147 results on '"Philip A. Bland"'
Search Results
2. The desert fireball network: A sensor network for meteorite tracking and recovery.
- Author
-
Jonathan P. Paxman, Philip A. Bland, Robert M. Howie, Martin C. Towner, Martin Cupak, Hadrien A. R. Devillepoix, and Eleanor K. Sansom
- Published
- 2016
- Full Text
- View/download PDF
3. The Winchcombe fireball—That lucky survivor
- Author
-
Sarah McMullan, Denis Vida, Hadrien A. R. Devillepoix, Jim Rowe, Luke Daly, Ashley J. King, Martin Cupák, Robert M. Howie, Eleanor K. Sansom, Patrick Shober, Martin C. Towner, Seamus Anderson, Luke McFadden, Jana Horák, Andrew R. D. Smedley, Katherine H. Joy, Alan Shuttleworth, Francois Colas, Brigitte Zanda, Áine C. O'Brien, Ian McMullan, Clive Shaw, Adam Suttle, Martin D. Suttle, John S. Young, Peter Campbell‐Burns, Richard Kacerek, Richard Bassom, Steve Bosley, Richard Fleet, Dave Jones, Mark McIntyre, Nick James, Derek Robson, Paul Dickinson, Philip A. Bland, Gareth S. Collins, McMullan, S [0000-0002-7194-6317], Vida, D [0000-0003-4166-8704], Devillepoix, HAR [0000-0001-9226-1870], Daly, L [0000-0002-7150-4092], King, AJ [0000-0001-6113-5417], Cupák, M [0000-0003-2193-0867], Howie, RM [0000-0002-5864-105X], Sansom, EK [0000-0003-2702-673X], Shober, P [0000-0003-4766-2098], Towner, MC [0000-0002-8240-4150], Anderson, S [0000-0002-8914-3264], Smedley, ARD [0000-0001-7137-6628], Joy, KH [0000-0003-4992-8750], Colas, F [0000-0002-0764-5042], O'Brien, ÁC [0000-0002-2591-7902], Suttle, MD [0000-0001-7165-2215], McIntyre, M [0000-0002-5769-4280], Bland, PA [0000-0002-4681-7898], Collins, GS [0000-0002-6087-6149], and Apollo - University of Cambridge Repository
- Subjects
Geophysics ,Space and Planetary Science ,5109 Space Sciences ,51 Physical Sciences - Abstract
On February 28, 2021, a fireball dropped ∼0.6 kg of recovered CM2 carbonaceous chondrite meteorites in South-West England near the town of Winchcombe. We reconstruct the fireball's atmospheric trajectory, light curve, fragmentation behavior, and pre-atmospheric orbit from optical records contributed by five networks. The progenitor meteoroid was three orders of magnitude less massive (∼13 kg) than any previously observed carbonaceous fall. The Winchcombe meteorite survived entry because it was exposed to a very low peak atmospheric dynamic pressure (∼0.6 MPa) due to a fortuitous combination of entry parameters, notably low velocity (13.9 km s−1). A near-catastrophic fragmentation at ∼0.07 MPa points to the body's fragility. Low entry speeds which cause low peak dynamic pressures are likely necessary conditions for a small carbonaceous meteoroid to survive atmospheric entry, strongly constraining the radiant direction to the general antapex direction. Orbital integrations show that the meteoroid was injected into the near-Earth region ∼0.08 Myr ago and it never had a perihelion distance smaller than ∼0.7 AU, while other CM2 meteorites with known orbits approached the Sun closer (∼0.5 AU) and were heated to at least 100 K higher temperatures.
- Published
- 2023
- Full Text
- View/download PDF
4. Taurid Stream #628: A Reservoir of Large Cometary Impactors
- Author
-
Hadrien A. R. Devillepoix, Peter Jenniskens, Philip A. Bland, Eleanor K. Sansom, Martin C. Towner, Patrick Shober, Martin Cupák, Robert M. Howie, Benjamin A. D. Hartig, Seamus Anderson, Trent Jansen-Sturgeon, and Jim Albers
- Published
- 2021
- Full Text
- View/download PDF
5. Trajectory, recovery, and orbital history of the Madura Cave meteorite
- Author
-
Hadrien A. R. Devillepoix, Eleanor K. Sansom, Patrick Shober, Seamus L. Anderson, Martin C. Towner, Anthony Lagain, Martin Cupák, Philip A. Bland, Robert M. Howie, Trent Jansen‐Sturgeon, Benjamin A. D. Hartig, Marcin Sokolowski, Gretchen Benedix, and Lucy Forman
- Subjects
Physics - Geophysics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Geophysics ,Space and Planetary Science ,FOS: Physical sciences ,Astrophysics - Earth and Planetary Astrophysics ,Geophysics (physics.geo-ph) - Abstract
On the 19th June 2020 at 20:05:07 UTC, a fireball lasting 5.5 s was observed above Western Australia by three Desert Fireball Network observatories. The meteoroid entered the atmosphere with a speed of $14.00 \pm 0.17$ km s$^{-1}$ and followed a $58^{\circ}$ slope trajectory from a height of 75 km down to 18.6 km. Despite the poor angle of triangulated planes between observatories (29$^{\circ}$) and the large distance from the observatories, a well constrained kilo-size main mass was predicted to have fallen just South of Madura in Western Australia. However, the search area was predicted to be large due to the trajectory uncertainties. Fortunately, the rock was rapidly recovered along the access track during a reconnaissance trip. The 1.072 kg meteorite called Madura Cave was classified as an L5 ordinary chondrite. The calculated orbit is of Aten type (mostly contained within the Earth's orbit), the second time only a meteorite is observed on such an orbit after Bunburra Rockhole. Dynamical modelling shows that Madura Cave has been in near-Earth space for a very long time. The NEO dynamical lifetime for the progenitor meteoroid is predicted to be $\sim87$ Myr. This peculiar orbit also points to a delivery from the main asteroid belt via the $\nu6$ resonance, and therefore an origin in the inner belt. This result contributes to drawing a picture for the existence of a present-day L chondrite parent body in the inner belt.
- Published
- 2022
- Full Text
- View/download PDF
6. Absolute time encoding for temporal super-resolution using de Bruijn coded exposures.
- Author
-
Robert M. Howie, Jonathan Paxman, Philip A. Bland, and Martin C. Towner
- Published
- 2020
- Full Text
- View/download PDF
7. Modeling of 3D trajectory of Hayabusa2 re-entry based on acoustic observations
- Author
-
Yasuhiro Nishikawa, Masa-yuki Yamamoto, Eleanor K Sansom, Hadrien A R Devillepoix, Martin C Towner, Yoshihiro Hiramatsu, Taichi Kawamura, Kazuhisa Fujita, Makoto Yoshikawa, Yoshiaki Ishihara, Islam Hamama, Norihisa Segawa, Yoshihiro Kakinami, Hiroshi Katao, Yuichiro Inoue, and Philip A Bland
- Subjects
Space and Planetary Science ,Astronomy and Astrophysics - Abstract
On 2020 December 5 at 17:28 UTC, Japan Aerospace Exploration Agency’s Hayabusa2 sample return capsule (SRC) re-entered Earth’s atmosphere. The capsule passed through the atmosphere at supersonic speeds, emitting sound and light. The inaudible sound was recorded by infrasound sensors installed by Kochi University of Technology and Curtin University. Based on analysis of the recorded infrasound, the trajectory of the SRC in two cases, one with constant-velocity linear motion and the other with silent flight, could be estimated with an accuracy of ${0{_{.}^{\circ}}5}$ in elevation and 1° in direction. A comparison with optical observations suggests a state of flight in which no light is emitted but sound is emitted. In this paper, we describe the method and results of the trajectory estimation.
- Published
- 2022
- Full Text
- View/download PDF
8. Mineralogy, petrology, geochemistry, and chronology of the Murrili (H5) meteorite fall: The third recovered fall from the Desert Fireball Network
- Author
-
K. Merigot, Philip A. Bland, Matthias M. M. Meier, Belinda Godel, Gretchen Benedix, Fred Jourdan, Marc W. Caffee, S. Wiggins, Ian A. Franchi, Trent Jansen-Sturgeon, Henner Busemann, Luke Daly, Trudi Kennedy, A. W. R. Bevan, J. M. Cadogan, Richard C. Greenwood, Martin C. Towner, Hadrien A. R. Devillepoix, Eleanor K. Sansom, Jon M. Friedrich, L. Esteban, Robert J. Macke, Robert M. Howie, Colin Maden, D. Stuart, D. Strangway, Seamus Anderson, Lucy V. Forman, Daniel T. Britt, Jonathan Paxman, Celia Mayers, Martin Cupak, and Kees C. Welten
- Subjects
Radionuclide ,Meteoroid ,Geochemistry ,Mineralogy ,Cosmic ray ,010502 geochemistry & geophysics ,01 natural sciences ,Texture (geology) ,Isotopes of oxygen ,Geophysics ,Meteorite ,13. Climate action ,Space and Planetary Science ,0103 physical sciences ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Chronology ,Ordinary chondrite - Abstract
Murrili, the third meteorite recovered by the Desert Fireball Network, is analyzed using mineralogy, oxygen isotopes, bulk chemistry, physical properties, noble gases, and cosmogenic radionuclides. The modal mineralogy, bulk chemistry, magnetic susceptibility, physical properties, and oxygen isotopes of Murrili point to it being an H5 ordinary chondrite. It is heterogeneously shocked (S2–S5), depending on the method used to determine it, although Murrili is not obviously brecciated in texture. Cosmogenic radionuclides yield a cosmic ray exposure age of 6–8 Ma, and a pre‐atmospheric meteoroid size of 15–20 cm in radius. Murrili’s fall and subsequent month‐long embedment into the salt lake Kati Thanda significantly altered the whole rock, evident in its Mossbauer spectra, and visual inspection of cut sections. Murrili may have experienced minor, but subsequent, impacts after its formation 4475.3 ± 2.3 Ma, which left it heterogeneously shocked.
- Published
- 2021
- Full Text
- View/download PDF
9. Tracing martian surface interactions with the triple O isotope compositions of meteoritic phosphates
- Author
-
Joshua F. Snape, Renaud E. Merle, Gavin G. Kenny, Philip A. Bland, Jeremy J. Bellucci, Gretchen Benedix, Alexander A. Nemchin, Martin J. Whitehouse, and Geology and Geochemistry
- Subjects
phosphates ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,Mars ,martian atmosphere ,010502 geochemistry & geophysics ,01 natural sciences ,Isotopes of oxygen ,Cl isotopes ,Perchlorate ,chemistry.chemical_compound ,martian surface ,Geochemistry and Petrology ,Martian surface ,Earth and Planetary Sciences (miscellaneous) ,triple oxygen ,0105 earth and related environmental sciences ,Martian ,Isotope ,Isotopes of chlorine ,Atmosphere of Mars ,Geophysics ,chemistry ,Meteorite ,13. Climate action ,Space and Planetary Science ,Geology - Abstract
The triple oxygen isotope compositions of phosphate grains in six martian meteorites have been measured by Secondary Ion Mass Spectrometry (SIMS) and combined together with their chlorine isotope and halogen concentrations have been used to constrain hydrosphere-lithosphere interactions on Mars. These samples include three enriched shergottites (Zagami, Roberts Massif 04262 and Larkman Nunatak 12011), one depleted shergottite (Tissint), an orthopyroxenite (Allan Hills 84001), and a regolith breccia (Northwest Africa 7533). The phosphates measured here have a range in δ18O [(18O/16O)sample/(18O/16O)Standard-1] × 103] from +1.0 to +6.8‰ and could be a result of indigenous mantle values, mixing with martian water, or replacement reactions taking place on the surface of Mars. Three samples have a Δ17O [δ17O-1000(1 + δ18O /1000)0.528-1] in equilibrium with the martian mantle (ALH 84001, Tissint, and Zagami), while three samples (LAR 12011, RBT 04262, and NWA 7533) have an elevated positive Δ17O outside of analytical uncertainty of the martian fractionation line (MFL). The phosphates in the latter group also have positive and negative δ37Cl [(37Cl/35Cl)sample/(37Cl/35Cl)standard – 1] × 103] and enrichments in halogens not seen in the rest of the sample suite. Perchlorate formation on Earth fractionates Cl in both positive and negative directions and generates a correlated positive Δ17O. Further, perchlorate has been detected in wt% amounts on the martian surface. Thus, these results strongly suggest the presence of multiple Cl isotope reservoirs on the martian surface that have interacted with the samples studied here over the last ca. 2 Ga of geologic time. The weighted average of Δ17O measurements from phosphate grains (n = 13) in NWA 7533, which are the explicit result of exchange reactions on the martian surface, yields a statistically robust mean value of 1.39 ± 0.19‰ (2σ, MSWD = 1.5, p = 0.13). This value likely represents an accurate estimate for an oxidized surface reservoir on Mars.
- Published
- 2020
- Full Text
- View/download PDF
10. A morphologic and crystallographic comparison of CV chondrite matrices
- Author
-
Patrick Trimby, Lucy V. Forman, Nicholas E. Timms, Luke Daly, Gretchen Benedix, and Philip A. Bland
- Subjects
education.field_of_study ,Materials science ,Population ,Chondrule ,010502 geochemistry & geophysics ,01 natural sciences ,Parent body ,Grain size ,Crystallography ,Geophysics ,Allende meteorite ,Meteorite ,Space and Planetary Science ,Chondrite ,0103 physical sciences ,education ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Electron backscatter diffraction - Abstract
Meteoritic matrices are commonly classified by their modal mineralogy, alteration, and shock levels. Other “textural” characteristics are not generally considered in classification schemes, yet could carry important information about their genesis and evolution. Terrestrial rocks are routinely described by grain morphology, which has led to morphology‐driven classifications, and identification of controlling processes. This paper investigates three CV chondrites—Allende (CV3.2oxA), Kaba (CV3.0oxB), and Vigarano (CV3.3red)—to determine the morphologic signature of olivine matrix grains. 2D grain size and shape, and crystallographic preferred orientations (CPOs) are quantified via electron backscatter diffraction mapping. Allende contains the largest and most elongate olivine grains, while Vigarano contains the least elongate, and Kaba contains the smallest grains. Weak but notable CPOs exist in some regions proximal to chondrules and one region distal to chondrules, and CPO geometries reveal a weak flattening of the matrix grains against the edge of chondrules within Allende. Kaba contains the least plastically deformed grains, and Allende contains the most plastically deformed grains. We tentatively infer that morphology is controlled by the characteristics of the available population of accreting grains, and aqueous and thermal alteration of the parent body. The extent of overall finite deformation is likely dictated by the location of the sample with respect to compression, the localized environment of the matrix with respect to surrounding material, and the post deformation temperature to induce grain annealing. Our systematic, quantitative process for characterizing meteorite matrices has the potential to provide a framework for comparison within and across meteorite classes, to help resolve how parent body processing differed across and between chondritic asteroids.
- Published
- 2019
- Full Text
- View/download PDF
11. The main asteroid belt: the primary source of debris on comet-like orbits
- Author
-
Eleanor K. Sansom, Hadrien A. R. Devillepoix, Robert M. Howie, Martin Cupak, Philip A. Bland, Benjamin A. D. Hartig, Martin C. Towner, Patrick Shober, and Seamus Anderson
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Solar System ,Near-Earth object ,010504 meteorology & atmospheric sciences ,Meteoroid ,Comet ,FOS: Physical sciences ,Astronomy and Astrophysics ,01 natural sciences ,Astrobiology ,Jupiter ,Geophysics ,Meteorite ,Space and Planetary Science ,Primary (astronomy) ,0103 physical sciences ,Earth and Planetary Sciences (miscellaneous) ,Asteroid belt ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Jupiter family comets contribute a significant amount of debris to near-Earth space. However, telescopic observations of these objects seem to suggest they have short physical lifetimes. If this is true, the material generated will also be short-lived, but fireball observation networks still detect material on cometary orbits. This study examines centimeter-meter scale sporadic meteoroids detected by the Desert Fireball Network from 2014-2020 originating from Jupiter family comet-like orbits. Analyzing each event's dynamic history and physical characteristics, we confidently determined whether they originated from the main asteroid belt or the trans-Neptunian region. Our results indicate that $, Published in The Planetary Science Journal
- Published
- 2021
12. The Scientific Need for a Dedicated Interplanetary Dust Instrument at Mars
- Author
-
L. D. Graham, Philip A. Bland, Apostolos A. Christou, J. S. New, Michael E. Zolensky, L. C. Welzenbach, J. Rojas, K. Fisher, Anna L. Butterworth, M. J. Genge, J. W. Ashley, Emmanuel Dartois, Matteo Crismani, Andrew Steele, Diego Janches, George J. Flynn, I. L. ten Kate, John M. C. Plane, Luther W. Beegle, Rohit Bhartia, Marc Fries, Mihaly Horanyi, J. Duprat, Pamela G. Conrad, Mark V. Sykes, Cécile Engrand, William J. Cooke, Aaron S. Burton, Mark A. Sephton, Zack Gainsforth, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Interplanetary dust cloud ,13. Climate action ,[SDU]Sciences of the Universe [physics] ,Mars Exploration Program ,Astrobiology - Abstract
International audience; Interplanetary dust is a scientifically important constituent of the Solar System that consists of material shed by asteroids, comets, and other airless bodies. As used here, the term “dust” includes interplanetary dust particles and micrometeoroids. Dust has been studied by missions such as Mariner, Pioneer, and Voyager in both interplanetary space and in the vicinity of most of the planets.To date, however, no dedicated interplanetary dust instrument has yet been employed for detailed analysis of the dust environment of Mars. Partial data on dust flux has been provided by the 1965 Mariner IV flyby, the MAVEN orbiter, and other missions, but a complete understanding of interplanetary dust abundance, composition, debris hazard, annual flux variation, and origins is lacking. These data are critical for understanding the effects of dust upon the martian system, including the carbonaceous input into the regolith of Mars and its moons, the chemical input into the martian atmosphere, potential effects upon remote sensing data, the hypothesized existence of a Phobos dust ring, and possible annual variations from meteor shower infall. These effects have direct ramifications for interpretation of Mars/Phobos/Deimos mission science and analysis of returned samples from those worlds. To remediate this shortfall, the authors recommend that a dedicated interplanetary dust analysis instrument should be included in the instrument package for an upcoming martian orbiter in the near term. Such an interplanetary dust analysis instrument should collect data over a time period of several martian years in order to generate a statistically robust data set on interplanetary dust concentration and flux over a wide range of mass, and to discern temporal variation over multiple martian years.
- Published
- 2021
- Full Text
- View/download PDF
13. 3D functional genomics screens identify CREBBP as a targetable driver in aggressive triple-negative breast cancer
- Author
-
Jyoti S. Choudhary, Lu Yu, Snezana Susnjar, Andrew Tutt, Patty Wai, Frances Daley, Natasa Medic Milijic, Rachael Natrajan, Daniela Kolarevic, Sophie Postel-Vinay, Barrie Peck, Ioanna Mavrommati, Hannah Cottom, Gareth Muirhead, Gillian Farnie, Gerard P. Quinn, Eleanor Knight, Rebecca Marlow, Richard Buus, Patrycja Gazinska, Simon S. McDade, Sunil Pancholi, Lesley-Ann Martin, Philip A. Bland, Naomi Guppy, Maggie C.U. Cheang, Sarah Maguire, Fredrik Wallberg, Amy Gibson, Paul H. Huang, Daniela Novo, Keith Brennan, Divya Kriplani, Farzana Noor, Giulia Falgari, Erle Holgersen, Eamonn Morrison, Syed Haider, Holly E. Barker, Kalnisha Naidoo, Ioannis Roxanis, and Lukas Krasny
- Subjects
0301 basic medicine ,Cancer Research ,Carcinogenesis ,new treatment strategies ,Triple Negative Breast Neoplasms ,law.invention ,Mice ,Triple-negative breast cancers (TNBC) ,0302 clinical medicine ,law ,Mice, Inbred NOD ,Molecular Targeted Therapy ,Triple-negative breast cancer ,Cells, Cultured ,treatment ,Manchester Cancer Research Centre ,Genomics ,CREB-Binding Protein ,in vivo ,Oncology ,030220 oncology & carcinogenesis ,Biomarker (medicine) ,Female ,Functional genomics ,Mice, Nude ,Drug Screening Assays, Antitumor/methods ,Article ,genomic heterogeneity ,03 medical and health sciences ,Cell Proliferation/genetics ,Breast cancer ,SDG 3 - Good Health and Well-being ,Downregulation and upregulation ,medicine ,Animals ,Humans ,CDK4/6i ,Neoplasm Invasiveness ,Lung cancer ,Protein Kinase Inhibitors ,Cell Proliferation ,CREB-Binding Protein/genetics ,business.industry ,ResearchInstitutes_Networks_Beacons/mcrc ,FOXM1 ,medicine.disease ,HCT116 Cells ,Xenograft Model Antitumor Assays ,Genomics/methods ,030104 developmental biology ,HEK293 Cells ,Protein Kinase Inhibitors/pharmacology ,Mutation ,Cancer research ,Suppressor ,Carcinogenesis/genetics ,Drug Screening Assays, Antitumor ,Triple Negative Breast Neoplasms/genetics ,business - Abstract
Triple-negative breast cancers (TNBC) are resistant to standard-of-care chemotherapy and lack known targetable driver gene alterations. Identification of novel drivers could aid the discovery of new treatment strategies for this hard-to-treat patient population, yet studies using high-throughput and accurate models to define the functions of driver genes in TNBC to date have been limited. Here, we employed unbiased functional genomics screening of the 200 most frequently mutated genes in breast cancer, using spheroid cultures to model in vivo–like conditions, and identified the histone acetyltransferase CREBBP as a novel tumor suppressor in TNBC. CREBBP protein expression in patient tumor samples was absent in 8% of TNBCs and at a high frequency in other tumors, including squamous lung cancer, where CREBBP-inactivating mutations are common. In TNBC, CREBBP alterations were associated with higher genomic heterogeneity and poorer patient survival and resulted in upregulation and dependency on a FOXM1 proliferative program. Targeting FOXM1-driven proliferation indirectly with clinical CDK4/6 inhibitors (CDK4/6i) selectively impaired growth in spheroids, cell line xenografts, and patient-derived models from multiple tumor types with CREBBP mutations or loss of protein expression. In conclusion, we have identified CREBBP as a novel driver in aggressive TNBC and identified an associated genetic vulnerability in tumor cells with alterations in CREBBP and provide a preclinical rationale for assessing CREBBP alterations as a biomarker of CDK4/6i response in a new patient population. Significance: This study demonstrates that CREBBP genomic alterations drive aggressive TNBC, lung cancer, and lymphomas and may be selectively treated with clinical CDK4/6 inhibitors.
- Published
- 2021
- Full Text
- View/download PDF
14. Taurid stream #628: a reservoir of large cometary impactors
- Author
-
Eleanor K. Sansom, Jim Albers, Robert M. Howie, Trent Jansen-Sturgeon, Martin Cupak, Peter Jenniskens, Benjamin A. D. Hartig, Patrick Shober, Hadrien A. R. Devillepoix, Seamus Anderson, Philip A. Bland, and Martin C. Towner
- Subjects
Meteor (satellite) ,Orbital elements ,Earth and Planetary Astrophysics (astro-ph.EP) ,education.field_of_study ,Meteoroid ,Population ,Comet ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Longitude of the periapsis ,Jupiter ,Geophysics ,Space and Planetary Science ,Asteroid ,Earth and Planetary Sciences (miscellaneous) ,education ,Geology ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The Desert Fireball Network observed a significant outburst of fireballs belonging to the Southern Taurid Complex of meteor showers between October 27 and November 17, 2015. At the same time, the Cameras for Allsky Meteor Surveillance project detected a distinct population of smaller meteors belonging to the irregular IAU shower #628, the s-Taurids. While this returning outburst was predicted and observed in previous work, the reason for this stream is not yet understood. 2015 was the first year that the stream was precisely observed, providing an opportunity to better understand its nature. We analyse the orbital elements of stream members, and establish a size frequency distribution from millimetre to metre size range. The stream is highly stratified with a large change of entry speed along Earth's orbit. We confirm that the meteoroids have orbital periods near the 7:2 mean-motion resonance with Jupiter. The mass distribution of this population is dominated by larger meteoroids, unlike that for the regular Southern Taurid shower. The distribution index is consistent with a gentle collisional fragmentation of weak material. A population of metre-sized objects is identified from satellite observations at a rate consistent with a continuation of the size-frequency distribution established at centimetre size. The observed change of longitude of perihelion among the s-Taurids points to recent (a few centuries ago) activity from fragmentation involving surviving asteroid 2015TX24. This supports a model for the Taurid Complex showers that involves an ongoing fragmentation cascade of comet 2P/Encke siblings following a breakup some 20,000 years ago., Comment: accepted in The Planetary Science Journal
- Published
- 2021
- Full Text
- View/download PDF
15. Statistical analysis of fireballs: Seismic signature survey
- Author
-
Hadrien A. R. Devillepoix, T. Neidhart, J.-L. Dimech, Eleanor K. Sansom, Katarina Miljković, Taichi Kawamura, Philip A. Bland, Mark A. Wieczorek, and Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- Subjects
Shock wave ,Seismometer ,010504 meteorology & atmospheric sciences ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,FOS: Physical sciences ,01 natural sciences ,Physics - Geophysics ,Atmosphere ,symbols.namesake ,[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology ,Observatory ,0103 physical sciences ,Range (statistics) ,Rayleigh wave ,Time series ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Astronomy and Astrophysics ,Geophysics (physics.geo-ph) ,Mach number ,13. Climate action ,Space and Planetary Science ,symbols ,Seismology ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Fireballs are infrequently recorded by seismic sensors on the ground. If recorded, they are usually reported as one-off events. This study is the first seismic bulk analysis of the largest single fireball data set, observed by the Desert Fireball Network (DFN) in Australia in the period 2014-2019. The DFN typically observes fireballs from cm-m scale impactors. We identified 25 fireballs in seismic time series data recorded by the Australian National Seismograph Network (ANSN). This corresponds to 1.8% of surveyed fireballs, at the kinetic energy range of 10$^6$ to 10$^{10}$ J. The peaks observed in the seismic time series data were consistent with calculated arrival times of the direct airwave or ground-coupled Rayleigh wave caused by shock waves by the fireball in the atmosphere (either due to fragmentation or the passage of the Mach cone). Our work suggests that identification of fireball events in the seismic time series data depends both on physical properties of a fireball (such as fireball energy and entry angle in the atmosphere) and the sensitivity of a seismic instrument. This work suggests that fireballs are likely detectable within 200 km direct air distance between a fireball and seismic station, for sensors used in the ANSN. If each DFN observatory had been accompanied by a seismic sensor of similar sensitivity, 50% of surveyed fireballs could have been detected. These statistics justify the future consideration of expanding the DFN camera network into the seismic domain., Comment: accepted for publication in PASA
- Published
- 2021
- Full Text
- View/download PDF
16. Author Correction: Shape of (101955) Bennu indicative of a rubble pile with internal stiffness
- Author
-
M. Lefevre, Aaron S. Burton, Carina Bennett, J. A. Mapel, Renu Malhotra, Peter Fleming, J. McAdams, N. Mogk, R. L. Ballouz, P. H. Smith, V. Nifo, C. K. Maleszewski, Timothy D. Swindle, E. Dotto, Stephen R. Schwartz, C. May, J. Bayron, D. Patterson, D. Guevel, Ellen S. Howell, Humberto Campins, J. Kissell, E. Brown, J. Wood, E. Muhle, John Robert Brucato, J. Small, B. Miller, Oleksiy Golubov, R. Pennington, K. Harshman, J. Nelson, Catherine Elder, M. McGee, R. Burns, J. Contreras, S. Hull, D. Kubitschek, D. Noss, Andrew J. Liounis, J. Backer, B. May, G. Fitzgibbon, J. Donaldson, D. Worden, Bashar Rizk, R. Witherspoon, Catherine L. Johnson, Erica Jawin, G. Shaw, A. Aqueche, Dolores H. Hill, D. Folta, S. Ferrone, M. Lujan, Giovanni Poggiali, B. G. Williams, S. Selznick, Melissa A. Morris, K. Rios, Sara S. Russell, D. Lambert, J. Hong, Jeffrey B. Plescia, H. Bloomenthal, D. Drinnon, Olivier S. Barnouin, Derek S. Nelson, Amanda E. Toland, Michael C. Moreau, J. A. Seabrook, K. Dill, A. Mirfakhrai, K. Hyde, J. D. P. Deshapriya, Hannah Kaplan, Timothy P. McElrath, Juliette I. Brodbeck, N. Ramos, S. Stewart, James B. Garvin, Sei-ichiro Watanabe, M. Arvizu-Jakubicki, Jason P. Dworkin, Matthew A. Siegler, Collin Lewin, Masatoshi Hirabayashi, L. Bloomquist, S. Gardner, Keiko Nakamura-Messenger, A. H. Nair, M. Schmitzer, P. Haas, Julie Bellerose, Dolan E. Highsmith, L. Koelbel, C. C. Lorentson, J. Zareski, E. Queen, S. R. Chesley, Philip A. Bland, A. Cheuvront, V. E. Hamilton, Ronald G. Mink, N. Mastrodemos, H. C. Connolly, K. Bellamy, M. Killgore, A. Gardner, Y. Takahashi, M. Lambert, R. C. Espiritu, Z. Zeszut, E. T. Morton, Kevin J. Walsh, Timothy D. Glotch, M. Skeen, Brian Kennedy, Matthew R.M. Izawa, G. Neumann, F. Teti, D. Doerres, A. Hasten, F. Ciceri, D. Howell, A. Deguzman, J. Nagy, D. Vaughan, H. Ma, C. Lantz, D. N. Brack, David K. Hammond, Erwan Mazarico, Leilah K. McCarthy, L. Rhoads, Kathleen L. Craft, C. Welch, Jay W. McMahon, C. L. Parish, D. C. Reuter, M. Giuntini, N. Castro, Clive Dickinson, J. Kreiner, K. Kingsbury, S. Dickenshied, Joseph A. Nuth, Alan R. Hildebrand, Erik Asphaug, H. Ido, Eric M. Sahr, A. Harbison, Arlin E. Bartels, T. Forrester, D. Eckart, R. Bandrowski, Michael K. Barker, Robert Gaskell, J. Wendel, S. Freund, Marc Bernacki, Ryan S. Park, A. Taylor, E. B. Bierhaus, S. Millington-Veloza, J. Stromberg, L. B. Breitenfeld, K. Stakkestad, D. Ellis, Timothy J. McCoy, M. Susak, Richard G. Cosentino, C. Manzoni, Hisayoshi Yurimoto, C. Drouet d'Aubigny, A. Bjurstrom, Masako Yoshikawa, S. Francis, J. Peachey, J. Geeraert, K. Marchese, O. Billett, M. Rascon, F. Jaen, B. Diallo, Martin Miner, Kris J. Becker, E. Mazzotta Epifani, Florian Thuillet, A. Knight, James H. Roberts, Pasquale Tricarico, Edward A. Cloutis, T. Fisher, Dale Stanbridge, A. Colpo, Osiris-Rex Team, S. Gonzales, Q. Tran, M. K. Crombie, John Marshall, N. Bojorquez-Murphy, David Vokrouhlický, Allen W. Lunsford, H. Bowles, K. L. Edmundson, R. A. Masterson, Peter G. Antreasian, N. Gorius, Benjamin Rozitis, D. Pino Muñoz, S. Carlson-Kelly, C. Thayer, J. Elsila Cook, B. C. Clark, N. Piacentine, José C. Aponte, M. Al Asad, M. A. Barucci, D. Blum, P. Falkenstern, Neil Bowles, Matthew Chojnacki, J. M. Leonard, J. Daly, K. Yetter, M. R. Fisher, Jeffrey N. Grossman, A. Boggs, N. Jayakody, Cristina A. Thomas, C.M. Ernst, Namrah Habib, J. N. Kidd, R. J. Steele, Andrew B. Calloway, Andrew Ryan, Kimberly T. Tait, Paul O. Hayne, J. Y. Li, K. L. Berry, William V. Boynton, Yanga R. Fernandez, D. A. Lorenz, M. Wasser, Daniel J. Scheeres, K. Fortney, A. Scroggins, B. Allen, B. Sutter, T. Ferro, Jonathan Joseph, Derek C. Richardson, D. Hoak, Brian Carcich, W. Chang, P. Wren, C. Boyles, Kaj E. Williams, B. Marty, J. Liang, J. Hoffman, A. Harch, Daniel R. Wibben, Jamie Molaro, S. Rieger, R. Enos, C. W. Hergenrother, Stephen R. Sutton, J. Grindlay, E. J. Lessac-Chenen, E. Huettner, C. Norman, P. Sherman, L. Swanson, M. Coltrin, S. Van wal, B. Buck, A. Fisher, Kevin Righter, Brian Rush, David D. Rowlands, Lauren McGraw, A. Levine, K. Drozd, D. Gaudreau, A. Nguyen, S. Sides, M. Chodas, R. Dubisher, B. Ashman, Michael Caplinger, Amy Simon, W. Moore, S. S. Balram-Knutson, R. Carpenter, S. Fornasier, Shogo Tachibana, Russell Turner, Ian A. Franchi, Trevor Ireland, Chloe B. Beddingfield, D. F. Everett, M. Corvin, Lindsay P. Keller, Tammy L. Becker, S. Carter, J. L. Rizos Garcia, Mark E. Perry, E. Keates, Michael C. Nolan, P. Vasudeva, C. Fellows, K. Herzog, Mark A. Jenkins, J. R. Weirich, J. Swenson, D. R. Golish, Davide Farnocchia, Lydia C. Philpott, Rebecca R. Ghent, Hannah C.M. Susorney, S. W. Squyres, Pedro Hasselmann, J. Hill, Thomas J. Zega, B. Key, Marco Delbo, A. S. French, P. Sánchez, A. Hilbert, J. Y. Pelgrift, R. P. Binzel, L. McNamara, Vishnu Reddy, Michael Daly, Scott Messenger, Daniella DellaGiustina, Maurizio Pajola, Charles Brunet, Joshua L. Bandfield, J. Padilla, A. Janakus, M. Moreau, R. Garcia, R. A. Chicoine, P. Michel, P. Kaotira, K. S. Johnson, J. Forelli, G. Miller, K. Martin, I. Galinsky, S. Desjardins, Naru Hirata, Christine Hartzell, M. L. Jones, S. Hooven, D. Velez, R. Munoz, Carolyn M. Ernst, C. Emr, N. Martinez-Vlasoff, S. Bendall, R. Zellar, E. Church, Theodore Kareta, T. Warren, P. Wolff, V. Morrison, C. Bryan, S. Bhaskaran, N. Jones, D. Hauf, Jeremy Bauman, R. T. Daly, R. Olds, M. M. Westermann, D. K. Hamara, E. Audi, G. Johnston, Eric Palmer, Courtney Mario, Daniel P. Glavin, T. Haltigin, J. Cutts, Javier Licandro, Xiao-Duan Zou, H. L. Roper, Gregory A. Neumann, William M. Owen, S. Sugita, Y. H. Tang, Kevin Burke, H. L. Enos, D. Gallagher, William F. Bottke, K. Getzandanner, Philip R. Christensen, C. W. V. Wolner, K. Fleshman, D. Poland, J. P. Emery, M.M. Riehl, D. Fennell, D. Sallitt, A. D. Rogers, M. Fitzgibbon, John H. Jones, S. Mullen, S. Salazar, S. Oliver, A. T. Polit, J. Cerna, A. Praet, Mark E. Holdridge, E. M. Ibrahim, Coralie D. Adam, J. de León, Christopher J. Miller, M. Ryle, J. Lyzhoft, M. Loveridge, C. Hoekenga, Brent J. Bos, S. Anwar, K. Chaffin, Devin L. Schrader, B. Lovelace, Romy D. Hanna, C. D. Adam, G. L. Mehall, K. L. Donaldson Hanna, F. Merlin, B. Wright, Guy Libourel, L. F. Lim, N. Shultz, Dante S. Lauretta, K. Hanley, Beth E. Clark, L. Le Corre, K. Thomas-Keprta, Moses Milazzo, W. Hagee, B. Page, M. Fisher, E. McDonough, D. Trang, S. Clemett, A. Rubi, A. Ingegneri, Scott A. Sandford, D. Dean, J. Freemantle, Michael D. Smith, Christopher W. Haberle, L. Nguyen, M. Fulchignoni, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL), Centre de Mise en Forme des Matériaux (CEMEF), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS]Physics [physics] ,010504 meteorology & atmospheric sciences ,Rubble ,Stiffness ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,[SDU]Sciences of the Universe [physics] ,engineering ,medicine ,General Earth and Planetary Sciences ,Geotechnical engineering ,medicine.symptom ,Pile ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Geology ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
International audience
- Published
- 2020
- Full Text
- View/download PDF
17. Using Atmospheric Impact Data to Model Meteoroid Close Encounters
- Author
-
Patrick Shober, Eleanor K. Sansom, Martin C. Towner, Philip A. Bland, Hadrien A. R. Devillepoix, Martin Cupak, Robert M. Howie, Trent Jansen-Sturgeon, and Benjamin A. D. Hartig
- Subjects
Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,education.field_of_study ,Solar System ,Meteoroid ,Population ,Flux ,FOS: Physical sciences ,Astronomy and Astrophysics ,Close encounter ,Astrophysics ,010502 geochemistry & geophysics ,01 natural sciences ,Meteorite ,13. Climate action ,Space and Planetary Science ,Asteroid ,0103 physical sciences ,Orbit (dynamics) ,education ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Based on telescopic observations of Jupiter-family comets (JFCs), there is predicted to be a paucity of objects at sub-kilometre sizes. However, several bright fireballs and some meteorites have been tenuously linked to the JFC population, showing metre-scale objects do exist in this region. In 2017, the Desert Fireball Network (DFN) observed a grazing fireball that redirected a meteoroid from an Apollo-type orbit to a JFC-like orbit. Using orbital data collected by the DFN, in this study, we have generated an artificial dataset of close terrestrial encounters that come within $1.5$ lunar distances (LD) of the Earth in the size-range of $0.01-100$kg. This range of objects is typically too small for telescopic surveys to detect, so using atmospheric impact flux data from fireball observations is currently one of the only ways to characterise these close encounters. Based on this model, we predict that within the considered size-range $2.5\times 10^{8}$ objects ($0.1\%$ of the total flux) from asteroidal orbits ($T_{J}>3$) are annually sent onto JFC-like orbits ($2, Comment: Accepted for publication in MNRAS
- Published
- 2020
18. Deriving Surface Ages on Mars Using Automated Crater Counting
- Author
-
Kevin Chai, Anthony Lagain, C. Norman, Seamus Anderson, Jonathan Paxman, Martin C. Towner, Gretchen Benedix, Shiv Meka, Tele Tan, and Philip A. Bland
- Subjects
Isochron ,Surface (mathematics) ,010504 meteorology & atmospheric sciences ,lcsh:Astronomy ,lcsh:QE1-996.5 ,geochronology ,Mars ,Mineralogy ,Mars Exploration Program ,Environmental Science (miscellaneous) ,01 natural sciences ,Crater counting ,lcsh:QB1-991 ,lcsh:Geology ,13. Climate action ,0103 physical sciences ,Geochronology ,isochron ,automated crater detection algorithm ,machine leaning ,General Earth and Planetary Sciences ,crater counting ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
Impact craters on solar system bodies are used to determine the relative ages of surfaces. The smaller the limiting primary crater size, the higher the spatial resolution in surface/resurfacing age dating. A manually counted database (Robbins & Hynek, 2012, https://doi.org/10.1029/2011JE003966) of >384,000 craters on Mars >1 km in diameter exists. But because crater size scales as a power law, the number of impact craters in the size range 10 m to 1 km is in the tens of millions, a number making precise analysis of local variations of age, over an entire surface, impossible to perform by manual counting. To decode this crater size population at a planetary scale, we developed an automated Crater Detection Algorithm based on the You Only Look Once v3 object detection system. The algorithm was trained by annotating images of the controlled Thermal Emission Imaging System daytime infrared data set. This training data set contains 7,048 craters that the algorithm used as a learning benchmark. The results were validated against the manually counted database as the ground truth data set. We applied our algorithm to the Thermal Emission Imaging System global mosaic between ±65° of latitude, returning a true positive detection rate of 91% and a diameter estimation error (~15%) consistent with typical manual count variation. Importantly, although a number of automated crater counting algorithms have been published, for the first time we demonstrate that automatic counting can be routinely used to derive robust surface ages.
- Published
- 2020
- Full Text
- View/download PDF
19. A mouse SWATH-MS reference spectral library enables deconvolution of species-specific proteomic alterations in human tumour xenografts
- Author
-
Rachael Natrajan, Amanda Swain, Ping-Chih Ho, Yi-Ru Yu, Lukas Krasny, Jian Ning, Philip A. Bland, Sophie E. Acton, Paul H. Huang, Mark L Elms, Víctor G. Martínez, Peter T. Harrison, Nadia Carvalho Lima, Laura Pacini, Beatrice A. Howard, Jessica Burns, and Fernando Calvo
- Subjects
0303 health sciences ,Swath ms ,Proteomic Profiling ,ved/biology ,ved/biology.organism_classification_rank.species ,Cell migration ,Computational biology ,Biology ,03 medical and health sciences ,0302 clinical medicine ,Stroma ,030220 oncology & carcinogenesis ,Proteome ,Breast ductal carcinoma ,Deconvolution ,Model organism ,030304 developmental biology - Abstract
SWATH-mass spectrometry (MS) enables accurate and reproducible proteomic profiling in multiple model organisms including the mouse. Here we present a comprehensive mouse reference spectral library (MouseRefSWATH) that permits quantification of up to 10,597 proteins (62.2% of the mouse proteome) by SWATH-MS. We exploit MouseRefSWATH to develop an analytical pipeline for species-specific deconvolution of proteomic alterations in human tumour xenografts (XenoSWATH). This method overcomes the challenge of high sequence similarity between mouse and human proteins, facilitating the study of host microenvironment-tumour interactions from ‘bulk tumour’ measurements. We apply the XenoSWATH pipeline to characterise an intraductal xenograft model of breast ductal carcinoma in-situ and uncover complex regulation of cell migration pathways that are not restricted to tumour cells but also operate in the mouse stroma upon progression to invasive disease. MouseRefSWATH and XenoSWATH opens new opportunities for in-depth and reproducible proteomic assessment to address wide-ranging biological questions involving this important model organism.
- Published
- 2020
- Full Text
- View/download PDF
20. A Global Fireball Observatory
- Author
-
Jonathan Horner, Eleanor K. Sansom, Robert M. Howie, Tracy Rushmer, P. J. A. Hill, D. C. Busan, Jim Albers, Peter Brown, Martin Cupak, Marc Fries, P. Jenniskens, Gretchen Benedix, A.D. Mardon, H. Darhmaoui, Trent Jansen-Sturgeon, Jonathan Tate, C. Shaw, M. Guennoun, Trevor Ireland, Geoffrey P. Bonning, Luke Daly, Gordon R. Osinski, H. Chennaoui Aoudjehane, Diego Janches, Martin C. Towner, Christopher D. K. Herd, Craig O'Neill, Gareth S. Collins, Z. Krzeminski, José Luis Hormaechea, Hadrien A. R. Devillepoix, Andrew Langendam, Carl Hergenrother, R. Sayers, S. McMullan, John Young, T. Y. Alrefay, A. Jabiri, A. Barka, Seamus Anderson, Mike Alexander, Patrick Shober, Philip A. Bland, L. Baeza, M. D. Suttle, Zouhair Benkhaldoun, Andrew G. Tomkins, Timothy D. Swindle, Benjamin A. D. Hartig, Young, John [0000-0001-6583-7643], Apollo - University of Cambridge Repository, and Science and Technology Facilities Council (STFC)
- Subjects
Solar System ,010504 meteorology & atmospheric sciences ,Meteors ,IMPACT ,Computer science ,Population ,FOS: Physical sciences ,Astronomy & Astrophysics ,01 natural sciences ,Astrobiology ,Observatory ,0201 Astronomical and Space Sciences ,0103 physical sciences ,NETWORK ,education ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Earth and Planetary Astrophysics (astro-ph.EP) ,education.field_of_study ,Science & Technology ,Meteoroid ,Astronomy and Astrophysics ,Meteoroids ,RECOVERY ,SUTTERS MILL METEORITE ,ORBIT ,RADAR ,Planetary science ,Pathfinder ,Asteroids: general ,EVENT ,Meteorite ,13. Climate action ,Space and Planetary Science ,Asteroid ,Physical Sciences ,FALL ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The world's meteorite collections contain a very rich picture of what the early Solar System would have been made of, however the lack of spatial context with respect to their parent population for these samples is an issue. The asteroid population is equally as rich in surface mineralogies, and mapping these two populations (meteorites and asteroids) together is a major challenge for planetary science. Directly probing asteroids achieves this at a high cost. Observing meteorite falls and calculating their pre-atmospheric orbit on the other hand, is a cheaper way to approach the problem. The Global Fireball Observatory (GFO) collaboration was established in 2017 and brings together multiple institutions (from Australia, USA, Canada, Morocco, Saudi Arabia, the UK, and Argentina) to maximise the area for fireball observation time and therefore meteorite recoveries. The members have a choice to operate independently, but they can also choose to work in a fully collaborative manner with other GFO partners. This efficient approach leverages the experience gained from the Desert Fireball Network (DFN) pathfinder project in Australia. The state-of-the art technology (DFN camera systems and data reduction) and experience of the support teams is shared between all partners, freeing up time for science investigations and meteorite searching. With all networks combined together, the GFO collaboration already covers 0.6% of the Earth's surface for meteorite recovery as of mid-2019, and aims to reach 2% in the early 2020s. We estimate that after 5 years of operation, the GFO will have observed a fireball from virtually every meteorite type. This combined effort will bring new, fresh, extra-terrestrial material to the labs, yielding new insights about the formation of the Solar System., Accepted in PSS. 19 pages, 9 figures
- Published
- 2020
21. Murrili meteorite's fall and recovery from Kati Thanda
- Author
-
M. A. Cox, Martin Cupak, Philip A. Bland, Hadrien A. R. Devillepoix, Jonathan Paxman, Trent Jansen-Sturgeon, Lucy V. Forman, Martin C. Towner, Eleanor K. Sansom, Gretchen Benedix, Benjamin A. D. Hartig, and Robert M. Howie
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Solar System ,Meteoroid ,FOS: Physical sciences ,Context (language use) ,010502 geochemistry & geophysics ,Geodesy ,01 natural sciences ,Fall line ,Automated data ,Atmosphere ,Geophysics ,Meteorite ,Space and Planetary Science ,0103 physical sciences ,010303 astronomy & astrophysics ,Geology ,Astrophysics - Earth and Planetary Astrophysics ,0105 earth and related environmental sciences - Abstract
On the 27th of November 2015, at 10:43:45.526 UTC, a fireball was observed across South Australia by ten Desert Fireball Network observatories lasting 6.1 s. A $\sim37$ kg meteoroid entered the atmosphere with a speed of 13.68$\pm0.09\,\mbox{km s}^{-1}$ and was observed ablating from a height of 85 km down to 18 km, having slowed to 3.28$\pm0.21 \,\mbox{km s}^{-1}$. Despite the relatively steep 68.5$^\circ$ trajectory, strong atmospheric winds significantly influenced the darkfight phase and the predicted fall line, but the analysis put the fall site in the centre of Kati Thanda - Lake Eyre South. Kati Thanda has metres-deep mud under its salt-encrusted surface. Reconnaissance of the area where the meteorite landed from a low flying aircraft revealed a 60 cm circular feature in the muddy lake, less than 50 m from the predicted fall line. After a short search, which again employed light aircraft, the meteorite was recovered on the 31st December 2015 from a depth of 42 cm. Murrili is the first recovered observed fall by the digital Desert Fireball Network (DFN). In addition to its scientific value, connecting composition to solar system context via orbital data, the recover demonstrates and validates the capabilities of the DFN, with its next generation remote observatories and automated data reduction pipeline.
- Published
- 2020
- Full Text
- View/download PDF
22. A mouse SWATH-MS reference spectral library enables deconvolution of species-specific proteomic alterations in human tumour xenografts
- Author
-
Mark L Elms, Jessica Burns, Yi-Ru Yu, Rachael Natrajan, Fernando Calvo, Beatrice A. Howard, Ping-Chih Ho, Amanda Swain, Peter T. Harrison, Paul H. Huang, Lukas Krasny, Jian Ning, Nadia Carvalho Lima, Laura Pacini, Sophie E. Acton, Philip A. Bland, and Víctor G. Martínez
- Subjects
0301 basic medicine ,Stromal cell ,ved/biology ,Proteomic Profiling ,ved/biology.organism_classification_rank.species ,Neuroscience (miscellaneous) ,Medicine (miscellaneous) ,Cell migration ,Computational biology ,Biology ,Proteomics ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Immunology and Microbiology (miscellaneous) ,Stroma ,030220 oncology & carcinogenesis ,Proteome ,Model organism ,Reprogramming - Abstract
SWATH-mass spectrometry (MS) enables accurate and reproducible proteomic profiling in multiple model organisms including the mouse. Here we present a comprehensive mouse reference spectral library (MouseRefSWATH) that permits quantification of up to 10,597 proteins (62.2% of the mouse proteome) by SWATH-MS. We exploit MouseRefSWATH to develop an analytical pipeline for species-specific deconvolution of proteomic alterations in human tumour xenografts (XenoSWATH). This method overcomes the challenge of high sequence similarity between mouse and human proteins, facilitating the study of host microenvironment-tumour interactions from ‘bulk tumour’ measurements. We apply the XenoSWATH pipeline to characterise an intraductal xenograft model of breast ductal carcinoma in-situ and uncover complex regulation consistent with stromal reprogramming, where the modulation of cell migration pathways is not restricted to tumour cells but also operate in the mouse stroma upon progression to invasive disease. MouseRefSWATH and XenoSWATH opens new opportunities for in-depth and reproducible proteomic assessment to address wide-ranging biological questions involving this important model organism.
- Published
- 2020
- Full Text
- View/download PDF
23. The Dingle Dell meteorite: A Halloween treat from the Main Belt
- Author
-
Jonathan Paxman, Martin C. Towner, Gretchen Benedix, M. A. Cox, Hadrien A. R. Devillepoix, Martin Cupak, Benjamin A. D. Hartig, Philip A. Bland, Eleanor K. Sansom, Trent Jansen-Sturgeon, and Robert M. Howie
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Meteoroid ,FOS: Physical sciences ,Astrophysics ,Large fragment ,010502 geochemistry & geophysics ,01 natural sciences ,Jupiter ,Geophysics ,Meteorite ,Space and Planetary Science ,Chondrite ,0103 physical sciences ,010303 astronomy & astrophysics ,Geology ,Astrophysics - Earth and Planetary Astrophysics ,0105 earth and related environmental sciences - Abstract
We describe the fall of the Dingle Dell (L/LL 5) meteorite near Morawa in Western Australia on October 31, 2016. The fireball was observed by six observatories of the Desert Fireball Network (DFN), a continental scale facility optimised to recover meteorites and calculate their pre-entry orbits. The $30\,\mbox{cm}$ meteoroid entered at 15.44 $\mbox{km s}^{-1}$, followed a moderately steep trajectory of $51^{\circ}$ to the horizon from 81 km down to 19 km altitude, where the luminous flight ended at a speed of 3.2 $\mbox{km s}^{-1}$. Deceleration data indicated one large fragment had made it to the ground. The four person search team recovered a 1.15 kg meteorite within 130 m of the predicted fall line, after 8 hours of searching, 6 days after the fall. Dingle Dell is the fourth meteorite recovered by the DFN in Australia, but the first before any rain had contaminated the sample. By numerical integration over 1 Ma, we show that Dingle Dell was most likely ejected from the main belt by the 3:1 mean-motion resonance with Jupiter, with only a marginal chance that it came from the $nu_6$ resonance. This makes the connection of Dingle Dell to the Flora family (currently thought to be the origin of LL chondrites) unlikely., Comment: 23 pages, 13 figures, accepted for publication in MAPS (MAPS-2892)
- Published
- 2018
- Full Text
- View/download PDF
24. Hydrothermal dynamics in a <scp>CM</scp> ‐based model of Ceres
- Author
-
B. J. Travis, Mark V. Sykes, William C. Feldman, and Philip A. Bland
- Subjects
Geophysics ,010504 meteorology & atmospheric sciences ,Space and Planetary Science ,0103 physical sciences ,Dynamics (mechanics) ,Atmospheric sciences ,010303 astronomy & astrophysics ,01 natural sciences ,Geology ,Hydrothermal circulation ,0105 earth and related environmental sciences - Published
- 2018
- Full Text
- View/download PDF
25. Submillisecond fireball timing using de Bruijn timecodes
- Author
-
Philip A. Bland, Martin C. Towner, Jonathan Paxman, Robert M. Howie, Eleanor K. Sansom, and Hadrien A. R. Devillepoix
- Subjects
Meteor (satellite) ,De Bruijn sequence ,Physics ,Meteoroid ,business.industry ,Astronomy ,010502 geochemistry & geophysics ,01 natural sciences ,Arrival time ,Geophysics ,Optics ,Meteorite ,Space and Planetary Science ,GNSS applications ,Shutter ,0103 physical sciences ,Point (geometry) ,business ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
Long-exposure fireball photographs have been used to systematically record meteoroid trajectories, calculate heliocentric orbits, and determine meteorite fall positions since the mid-20th century. Periodic shuttering is used to determine meteoroid velocity, but up until this point, a separate method of precisely determining the arrival time of a meteoroid was required. We show it is possible to encode precise arrival times directly into the meteor image by driving the periodic shutter according to a particular pattern—a de Bruijn sequence—and eliminate the need for a separate subsystem to record absolute fireball timing. The Desert Fireball Network has implemented this approach using a microcontroller driven electro-optic shutter synchronized with GNSS UTC time to create small, simple, and cost-effective high-precision fireball observatories with submillisecond timing accuracy.
- Published
- 2017
- Full Text
- View/download PDF
26. How to build a continental scale fireball camera network
- Author
-
Martin Cupak, Philip A. Bland, Robert M. Howie, Martin C. Towner, Eleanor K. Sansom, Jonathan Paxman, and Hadrien A. R. Devillepoix
- Subjects
Physics ,business.product_category ,Meteoroid ,Concurrent engineering ,Astronomy and Astrophysics ,010502 geochemistry & geophysics ,01 natural sciences ,Network planning and design ,Space and Planetary Science ,Observatory ,Timecode ,Shutter ,0103 physical sciences ,Engineering design process ,business ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Digital camera ,Remote sensing - Abstract
The expansion of the Australian Desert Fireball Network has been enabled by the development of a new digital fireball observatory based around a consumer digital camera. The observatories are more practical and much more cost effective than previous solutions whilst retaining high imaging performance. This was made possible through a flexible concurrent design approach, a careful focus on design for manufacture and assembly, and by considering installation and maintenance early in the design process. A new timing technique for long exposure fireball observatories was also developed to remove the need for a separate timing subsystem and data integration from multiple instruments. A liquid crystal shutter is used to modulate light transmittance during the long exposure which embeds a timecode into the fireball images for determining fireball arrival times and velocities. Using these observatories, the Desert Fireball Network has expanded to cover approximately 2.5 million square kilometres (around one third of Australia). The observatory and network design has been validated via the recovery of the Murrili Meteorite in South Australia through a systematic search at the end of 2015 and the calculation of a pre-atmospheric entry orbit. This article presents an overview of the design, implementation and performance of the new fireball observatories.
- Published
- 2017
- Full Text
- View/download PDF
27. Impact-induced compaction of primitive solar system solids: The need for mesoscale modelling and experiments
- Author
-
James G. Derrick, David J. Chapman, Daniel E. Eakins, Michael E. Rutherford, Gareth S. Collins, Philip A. Bland, Thomas M. Davison, Science and Technology Facilities Council (STFC), AWE Plc, and Engineering and Physical Sciences Research Council
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,Compaction ,Chondrule ,Mineralogy ,General Medicine ,01 natural sciences ,Matrix (geology) ,Shock (mechanics) ,Meteorite ,MD Multidisciplinary ,0103 physical sciences ,Hypervelocity ,Composite material ,Porosity ,010303 astronomy & astrophysics ,Lithification ,0105 earth and related environmental sciences - Abstract
Primitive solar system solids were accreted as highly porous bimodal mixtures of mm-sized chondrules and sub-μm matrix grains. To understand the compaction and lithification of these materials by shock, it is necessary to investigate the process at the mesoscale; i.e., the scale of individual chondrules. Here we document simulations of hypervelocity compaction of primitive materials using the iSALE shock physics model. We compare the numerical methods employed here with shock compaction experiments involving bimodal mixtures of glass beads and silica powder and find good agreement in bulk material response between the experiments and models. The heterogeneous response to shock of bimodal porous mixtures with a composition more appropriate for primitive solids was subsequently investigated: strong temperature dichotomies between the chondrules and matrix were observed (non-porous chondrules remained largely cold, while the porous matrix saw temperature increases of 100’s K). Matrix compaction was heterogeneous, and post-shock porosity was found to be lower on the lee-side of chondrules. The strain in the matrix was shown to be higher near the chondrule rims, in agreement with observations from meteorites. Chondrule flattening in the direction of the shock increases with increasing impact velocity, with flattened chondrules oriented with their semi-minor axis parallel to the shock direction.
- Published
- 2017
- Full Text
- View/download PDF
28. Mammary lineage restriction in development
- Author
-
Beatrice A. Howard and Philip A. Bland
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,Lineage (genetic) ,medicine.anatomical_structure ,Mammary gland ,medicine ,Cell Biology ,Biology ,Embryonic stem cell ,Cell biology - Abstract
The establishment of the two distinct lineages that form the branched epithelial ductal tree of the mammary gland is a complex and essential developmental process. Two independent studies now describe the switch from multipotency to unipotency as an embryonic process and outline mechanisms of early lineage restriction.
- Published
- 2018
- Full Text
- View/download PDF
29. Absolute time encoding for temporal super-resolution using de Bruijn coded exposures
- Author
-
Jonathan Paxman, Robert M. Howie, Martin C. Towner, and Philip A. Bland
- Subjects
De Bruijn sequence ,Computer science ,business.industry ,Track (disk drive) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,010502 geochemistry & geophysics ,Tracking (particle physics) ,01 natural sciences ,Computer Science Applications ,Particle image velocimetry ,Hardware and Architecture ,Encoding (memory) ,0103 physical sciences ,Pattern recognition (psychology) ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,United States Space Surveillance Network ,business ,Orbit determination ,010303 astronomy & astrophysics ,Software ,0105 earth and related environmental sciences - Abstract
Many target tracking tasks require high spatial and temporal precision. High frame rate imaging at high spatial resolution is commonly used in these applications, but this approach is expensive and generates large amounts of data which can complicate implementation. When tracking a single object in motion, almost all of this information is unused. A technique has been developed to exploit this sparsity and track motion with a long exposure where absolute timing is encoded by modulating the exposure over time according to a de Bruijn sequence. This technique has been implemented in the Desert Fireball Network to track bright meteors entering the Earth’s atmosphere for orbit determination and successful meteorite recovery. An alternate proof of concept implementation was also developed demonstrating tracking at 36 megapixels and 1000 Hz using a consumer camera with an inexpensive modulated light source and retroreflective target. The technique could be applied to other tracking problems requiring high temporal and spatial precision such as particle image velocimetry and space surveillance and tracking.
- Published
- 2019
- Full Text
- View/download PDF
30. Where Did They Come From, Where Did They Go. Grazing Fireballs
- Author
-
Robert M. Howie, Eleanor K. Sansom, Benjamin A. D. Hartig, Philip A. Bland, Trent Jansen-Sturgeon, Patrick Shober, Hadrien A. R. Devillepoix, Martin C. Towner, and Martin Cupak
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,Solar System ,010504 meteorology & atmospheric sciences ,Meteoroid ,Event (relativity) ,Comet ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Close encounter ,01 natural sciences ,Jupiter ,Atmosphere ,Space and Planetary Science ,0103 physical sciences ,Orbit (control theory) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
For centuries extremely-long grazing fireball displays have fascinated observers and inspired people to ponder about their origins. The Desert Fireball Network (DFN) is the largest single fireball network in the world, covering about one third of Australian skies. This expansive size has enabled us to capture a majority of the atmospheric trajectory of a spectacular grazing event that lasted over90 seconds, penetrated as deep as ~58.5km, and traveled over 1,300 km through the atmosphere before exiting back into interplanetary space. Based on our triangulation and dynamic analyses of the event, we have estimated the initial mass to be at least 60 kg, which would correspond to a30 cm object given a chondritic density (3500 kg m-3). However, this initial mass estimate is likely a lower bound, considering the minimal deceleration observed in the luminous phase. The most intriguing quality of this close encounter is that the meteoroid originated from an Apollo-type orbit and was inserted into a Jupiter-family comet (JFC) orbit due to the net energy gained during the close encounter with the Earth. Based on numerical simulations, the meteoroid will likely spend ~200kyrs on a JFC orbit and have numerous encounters with Jupiter, the first of which will occur in January-March 2025. Eventually the meteoroid will likely be ejected from the Solar System or be flung into a trans-Neptunian orbit., Accepted for publication in AJ
- Published
- 2019
31. Recreating the OSIRIS-REx Slingshot Manoeuvre from a Network of Ground-Based Sensors
- Author
-
Martin Cupak, Alastair W. Tait, J. Calcino, Terence P. McClafferty, Eleanor K. Sansom, Robert M. Howie, M. A. Cox, Martin C. Towner, Gregory J. Madsen, Jennifer T. Mitchell, N. D. Nevill, Benjamin A. D. Hartig, B. M. Henson, Hadrien A. R. Devillepoix, Trent Jansen-Sturgeon, Geoffrey P. Bonning, Craig O'Neill, Jake T. Clark, Samuel J. Matthews, Zacchary N. P. Hoskins, Luke T. Smith, Philip A. Bland, and Andrew Langendam
- Subjects
Physics ,010504 meteorology & atmospheric sciences ,Spacecraft ,business.industry ,FOS: Physical sciences ,Astronomy and Astrophysics ,Field of view ,Tracking (particle physics) ,01 natural sciences ,Space and Planetary Science ,Observatory ,0103 physical sciences ,Orbit (dynamics) ,Trajectory ,United States Space Surveillance Network ,business ,Orbit determination ,Astrophysics - Instrumentation and Methods for Astrophysics ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,0105 earth and related environmental sciences ,Remote sensing - Abstract
Optical tracking systems typically trade off between astrometric precision and field of view. In this work, we showcase a networked approach to optical tracking using very wide field-of-view imagers that have relatively low astrometric precision on the scheduled OSIRIS-REx slingshot manoeuvre around Earth on 22 Sep 2017. As part of a trajectory designed to get OSIRIS-REx to NEO 101955 Bennu, this flyby event was viewed from 13 remote sensors spread across Australia and New Zealand to promote triangulatable observations. Each observatory in this portable network was constructed to be as lightweight and portable as possible, with hardware based off the successful design of the Desert Fireball Network. Over a 4-h collection window, we gathered 15 439 images of the night sky in the predicted direction of the OSIRIS-REx spacecraft. Using a specially developed streak detection and orbit determination data pipeline, we detected 2 090 line-of-sight observations. Our fitted orbit was determined to be within about 10 km of orbital telemetry along the observed 109 262 km length of OSIRIS-REx trajectory, and thus demonstrating the impressive capability of a networked approach to Space Surveillance and Tracking.
- Published
- 2019
32. Fireball streak detection with minimal CPU processing requirements for the Desert Fireball Network data processing pipeline
- Author
-
Eleanor K. Sansom, Martin C. Towner, Jean Deshayes, Philip A. Bland, Trent Jansen-Sturgeon, Hadrien A. R. Devillepoix, Martin Cupak, Jonathan Paxman, Robert M. Howie, and Ben Hartig
- Subjects
Pipeline (computing) ,Streak ,FOS: Physical sciences ,Image processing ,Processing ,010502 geochemistry & geophysics ,01 natural sciences ,Hough transform ,law.invention ,law ,0103 physical sciences ,False positive paradox ,Computer vision ,Sensitivity (control systems) ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,computer.programming_language ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,Artificial neural network ,business.industry ,Astronomy and Astrophysics ,Space and Planetary Science ,Artificial intelligence ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,computer ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The detection of fireballs streaks in astronomical imagery can be carried out by a variety of methods. The Desert Fireball Network--DFN--uses a network of cameras to track and triangulate incoming fireballs to recover meteorites with orbits. Fireball detection is done on-camera, but due to the design constraints imposed by remote deployment, the cameras are limited in processing power and time. We describe the processing software used for fireball detection under these constrained circumstances. A cascading approach was implemented, whereby computationally simple filters are used to discard uninteresting portions of the images, allowing for more computationally expensive analysis of the remainder. This allows a full night's worth of data; over 1000 36 megapixel images to be processed each day using a low power single board computer. The algorithms chosen give a single camera successful detection large fireball rate of better than 96 percent, when compared to manual inspection, although significant numbers of false positives are generated. The overall network detection rate for triangulated large fireballs is estimated to be better than 99.8 percent, by ensuring that there are multiple double stations chances to detect one fireball., 20 pages, 5 figures
- Published
- 2019
33. Amazonian chemical weathering rate derived from stony meteorite finds at Meridiani Planum on Mars
- Author
-
M. P. Golombek, John A. Grant, Nicholas H. Warner, Philip A. Bland, Christian Schröder, and J. W. Ashley
- Subjects
Meridiani Planum ,Multidisciplinary ,010504 meteorology & atmospheric sciences ,Water on Mars ,Amazonian ,Science ,General Physics and Astronomy ,General Chemistry ,Mars Exploration Program ,010502 geochemistry & geophysics ,Exploration of Mars ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Article ,Astrobiology ,Mars rover ,Meteorite ,Composition of Mars ,Geology ,0105 earth and related environmental sciences - Abstract
Spacecraft exploring Mars such as the Mars Exploration Rovers Spirit and Opportunity, as well as the Mars Science Laboratory or Curiosity rover, have accumulated evidence for wet and habitable conditions on early Mars more than 3 billion years ago. Current conditions, by contrast, are cold, extremely arid and seemingly inhospitable. To evaluate exactly how dry today's environment is, it is important to understand the ongoing current weathering processes. Here we present chemical weathering rates determined for Mars. We use the oxidation of iron in stony meteorites investigated by the Mars Exploration Rover Opportunity at Meridiani Planum. Their maximum exposure age is constrained by the formation of Victoria crater and their minimum age by erosion of the meteorites. The chemical weathering rates thus derived are ∼1 to 4 orders of magnitude slower than that of similar meteorites found in Antarctica where the slowest rates are observed on Earth., Little is known about the impacts of Mars' contemporary dryness on weathering processes. Here, using iron oxidation estimates from the Mars Rover Opportunity, the authors quantify chemical weathering rates for Mars, finding appreciably slower rates compared with the lowest values on Earth.
- Published
- 2016
34. A Pb isotopic resolution to the Martian meteorite age paradox
- Author
-
Martin J. Whitehouse, Gretchen Benedix, Jeremy J. Bellucci, Joshua F. Snape, Philip A. Bland, Alexander A. Nemchin, and Ross Kielman
- Subjects
Martian ,Radiogenic nuclide ,010504 meteorology & atmospheric sciences ,Isotope ,Geochemistry ,Northern Hemisphere ,Crust ,Mars Exploration Program ,010502 geochemistry & geophysics ,01 natural sciences ,Astrobiology ,Geophysics ,Meteorite ,Space and Planetary Science ,Geochemistry and Petrology ,Clastic rock ,Earth and Planetary Sciences (miscellaneous) ,Geology ,0105 earth and related environmental sciences - Abstract
Determining the chronology and quantifying various geochemical reservoirs on planetary bodies is fundamental to understanding planetary accretion, differentiation, and global mass transfer. The Pb isotope compositions of individual minerals in the Martian meteorite Chassigny have been measured by Secondary Ion Mass Spectrometry (SIMS). These measurements indicate that Chassigny has mixed with a Martian reservoir that evolved with a long-term 238U/204Pb (μ) value ∼ two times higher than those inferred from studies of all other Martian meteorites except 4.428 Ga clasts in NWA7533. Any significant mixing between this and an unradiogenic reservoir produces ambiguous trends in Pb isotope variation diagrams. The trend defined by our new Chassigny data can be used to calculate a crystallization age for Chassigny of 4.526 ± 0.027 Ga (2σ) that is clearly in error as it conflicts with all other isotope systems, which yield a widely accepted age of 1.39 Ga. Similar, trends have also been observed in the Shergottites and have been used to calculate a >4 Ga age or, alternatively, attributed to terrestrial contamination. Our new Chassigny data, however, argue that the radiogenic component is Martian, mixing occurred on the surface of Mars, and is therefore likely present in virtually every Martian meteorite. The presence of this radiogenic reservoir on Mars resolves the paradox between Pb isotope data and all other radiogenic isotope systems in Martian meteorites. Importantly, Chassigny and the Shergottites are likely derived from the northern hemisphere of Mars, while NWA 7533 originated from the Southern hemisphere, implying that the U-rich reservoir, which most likely represents some form of crust, must be widespread. The significant age difference between SNC meteorites and NWA 7533 is also consistent with an absence of tectonic recycling throughout Martian history.
- Published
- 2016
- Full Text
- View/download PDF
35. A Dynamic Trajectory Fit to Multisensor Fireball Observations
- Author
-
Robert M. Howie, Eleanor K. Sansom, Martin C. Towner, Hadrien A. R. Devillepoix, Philip A. Bland, Benjamin A. D. Hartig, and Trent Jansen-Sturgeon
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,010504 meteorology & atmospheric sciences ,Meteoroid ,business.industry ,FOS: Physical sciences ,Astronomy and Astrophysics ,01 natural sciences ,Physics::Geophysics ,13. Climate action ,Space and Planetary Science ,Physics::Space Physics ,0103 physical sciences ,Trajectory ,Astrophysics::Earth and Planetary Astrophysics ,Aerospace engineering ,business ,010303 astronomy & astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,0105 earth and related environmental sciences - Abstract
Meteorites with known orbital origins are key to our understanding of Solar System formation and the source of life on Earth. However, these pristine samples of space material are incredibly rare. Less than 40 of the 60,000 meteorites held in collections around the world have known dynamical origins. Fireball networks have been developed globally in a unified effort to increase this number by using multiple observatories to record, triangulate, and dynamically analyse ablating meteoroids as they enter our atmosphere. The accuracy of the chosen meteoroid triangulation method directly influences the accuracy of the determined orbit and the likelihood of possible meteorite recovery. There are three leading techniques for meteoroid triangulation discussed in the literature: the Method of Planes, the Straight Line Least Squares method, and the Multi-Parameter Fit method. Here we describe an alternative method to meteoroid triangulation, called the Dynamic Trajectory Fit. This approach uses the meteoroid's 3D dynamic equations of motion to fit a realistic trajectory directly to multi-sensor line-of-sight observations. This method has the ability to resolve fragmentation events, fit systematic observatory timing offsets, and determine mass estimates of the meteoroid along its observable trajectory. Through a comprehensive Monte-Carlo analysis of over 100,000 trajectory simulations, we find this new method to more accurately estimate meteoroid trajectories of slow entry events ($
- Published
- 2020
- Full Text
- View/download PDF
36. Sox9 regulates cell state and activity of embryonic mouse mammary progenitor cells
- Author
-
Mandy Tsang, Erik Oliemuller, Naoko Kogata, Philip A. Bland, Anne Lowe, and Beatrice A. Howard
- Subjects
0301 basic medicine ,education.field_of_study ,Population ,Mammary gland ,Medicine (miscellaneous) ,Biology ,Embryonic stem cell ,General Biochemistry, Genetics and Molecular Biology ,Article ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,lcsh:Biology (General) ,Downregulation and upregulation ,Cell culture ,030220 oncology & carcinogenesis ,medicine ,Progenitor cell ,Stem cell ,General Agricultural and Biological Sciences ,education ,Clone (B-cell biology) ,lcsh:QH301-705.5 - Abstract
Embryonic mammary cells are a unique population comprised of undifferentiated, highly plastic progenitor cells that create normal mammary tissues. The mammary gland continues to develop after birth from descendants of embryonic mammary cells. Here, we establish cell lines from mouse mammary organs, immediately after they formed during prenatal development, to facilitate studies of primitive mammary cells, which are difficult to isolate in sufficient quantities for use in functional experiments. We show that some lines can be induced to secrete milk, a distinguishing feature of mammary epithelial cells. Targeted deletion of Sox9, from one clone, decreases the ability to respond to lactogenic stimuli, consistent with a previously identified role for Sox9 in regulating luminal progenitor function. Sox9 ablation also leads to alterations in 3D morphology and downregulation of Zeb1, a key epithelial–mesenchymal transition regulator. Prenatal mammary cell lines are an invaluable resource to study regulation of mammary progenitor cell biology and development., Naoko Kogata et al. generated murine mammary progenitor cell lines that form spheres and secrete milk upon hormonal stimulation. Deletion of Sox9 increased the ability of these cells to forms spheres but decreased milk production induced by lactogenic stimuli, consistent with the role of this transcription factor on maintaining the stem cell state.
- Published
- 2018
37. Observation of metre-scale impactors by the Desert Fireball Network
- Author
-
Trent Jansen-Sturgeon, Benjamin A. D. Hartig, Martin Cupak, Eleanor K. Sansom, Martin C. Towner, Philip A. Bland, Hadrien A. R. Devillepoix, Robert M. Howie, and M. A. Cox
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,Meteoroid ,010308 nuclear & particles physics ,Desert (particle physics) ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,01 natural sciences ,Orbit ,Meteorite ,Space and Planetary Science ,Asteroid ,Planet ,0103 physical sciences ,Low Mass ,Scale (map) ,010303 astronomy & astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The Earth is impacted by 35-40 metre-scale objects every year. These meteoroids are the low mass end of impactors that can do damage on the ground. Despite this they are very poorly surveyed and characterised, too infrequent for ground based fireball bservation efforts, and too small to be efficiently detected by NEO telescopic surveys whilst still in interplanetary space. We want to evaluate the suitability of different instruments for characterising metre-scale impactors and where they come from. We use data collected over the first 3 years of operation of the continent-scale Desert Fireball Network, and compare results with other published results as well as orbital sensors. We find that although the orbital sensors have the advantage of using the entire planet as collecting area, there are several serious problems with the accuracy of the data, notably the reported velocity vector, which is key to getting an accurate pre-impact orbit and calculating meteorite fall positions. We also outline dynamic range issues that fireball networks face when observing large meteoroid entries., 13 pages, 6 figures
- Published
- 2018
38. Comparing Analytical and Numerical Approaches to Meteoroid Orbit Determination using Hayabusa Telemetry
- Author
-
Eleanor K. Sansom, Trent Jansen-Sturgeon, and Philip A. Bland
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Meteoroid ,Spacecraft ,business.industry ,FOS: Physical sciences ,Perturbation (astronomy) ,Atmospheric model ,010502 geochemistry & geophysics ,Geodesy ,01 natural sciences ,Geophysics ,Space and Planetary Science ,Asteroid ,0103 physical sciences ,Physics::Space Physics ,Trajectory ,Orbit (dynamics) ,Astrophysics::Earth and Planetary Astrophysics ,business ,Orbit determination ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Fireball networks establish the trajectories of meteoritic material passing through Earth's atmosphere, from which they can derive pre-entry orbits. Triangulated atmospheric trajectory data requires different orbit determination methods to those applied to observational data beyond the Earth's sphere-of-influence, such as telescopic observations of asteroids. Currently, the vast majority of fireball networks determine and publish orbital data using an analytical approach, with little flexibility to include orbital perturbations. Here we present a novel numerical technique for determining meteoroid orbits from fireball network data and compare it to previously established methods. The re-entry of the Hayabusa spacecraft, with its known pre-Earth orbit, provides a unique opportunity to perform this comparison as it was observed by fireball network cameras. As initial sightings of the Hayabusa spacecraft and capsule were made at different altitudes, we are able to quantify the atmosphere's influence on the determined pre-Earth orbit. Considering these trajectories independently, we found the orbits determined by the novel numerical approach to align closer to JAXA's telemetry in both cases. Comparing the orbits determined from the capsule's re-entry shows the need for an atmospheric model, which the prevailing analytical approach lacks. Using simulations, we determine the atmospheric perturbation to become significant at ~90 km; higher than the first observations of typical meteorite dropping events. Using further simulations, we find the most substantial differences between techniques to occur at both low entry velocities and Moon passing trajectories. These regions of comparative divergence demonstrate the need for perturbation inclusion within the chosen orbit determination algorithm., 17 pages, 8 figures
- Published
- 2018
39. Opening the dynamic infrared sky
- Author
-
Anna M. Moore, Jarek Antoszewski, Roberto Soria, Jennifer L. Sokoloski, Michael C. B. Ashley, Robert A. Simcoe, Jeff Cooke, Eran O. Ofek, Jill Burnham, Kaushik De, Alexander Heger, Kenneth C. Freeman, Tony Travouillon, J. Soon, Jacob E. Jencson, David Hale, Lee R. Spitler, Stuart D. Ryder, Roger Smith, Orsola De Marco, Mansi M. Kasliwal, D. McKenna, Alexandre Delacroix, Scott M. Adams, Valery Terebizh, Joss Bland-Hawthorn, Ryan M. Lau, Michael Jones, Philip A. Bland, Marshall, Heather K., Spyromilio, Jason, and Gilmozzi, Roberto
- Subjects
010308 nuclear & particles physics ,Infrared ,media_common.quotation_subject ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,The Renaissance ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Stars ,Sky ,Observatory ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Geology ,media_common - Abstract
While optical and radio transient surveys have enjoyed a renaissance over the past decade, the dynamic infrared sky remains virtually unexplored from the ground. The infrared is a powerful tool for probing transient events in dusty regions that have high optical extinction, and for detecting the coolest of stars that are bright only at these wavelengths. The fundamental roadblocks in studying the infrared time-domain have been the overwhelmingly bright sky background (250 times brighter than optical) and the narrow field-of-view of infrared cameras (largest is VISTA at 0.6 sq deg). To address these challenges, Palomar Gattini-IR is currently under construction at Palomar Observatory and we propose a further low risk, economical, and agile instrument to be located at Siding Spring Observatory, as well as further instruments which will be located at the high polar regions to take advantage of the low thermal sky emission, particularly in the 2.5 micron region.
- Published
- 2018
- Full Text
- View/download PDF
40. Planetary Surface Processes
- Author
-
Susanne P. Schwenzer and Philip A. Bland
- Subjects
Planetary surface ,Geology ,Astrobiology - Published
- 2018
- Full Text
- View/download PDF
41. A novel approach to fireball modeling: The observable and the calculated
- Author
-
Martin C. Towner, Philip A. Bland, Jonathan Paxman, and Eleanor K. Sansom
- Subjects
Physics ,Meteoroid ,Cosmic ray ,Observable ,Astrophysics ,Extended Kalman filter ,Geophysics ,Meteorite ,Space and Planetary Science ,Parametric model ,Determination methods ,Astrophysics::Earth and Planetary Astrophysics ,Statistical physics ,Dynamic method - Abstract
Estimating the mass of a meteoroid passing through the Earth's atmosphere is essential to determining potential meteorite fall positions. High-resolution fireball images from dedicated camera networks provide the position and timing for fireball bright flight trajectories. There are two established mass determination methods: the photometric and the dynamic. A new approach is proposed, based on the dynamic method. A dynamic optimization initially constrains unknown meteoroid characteristics which are then used in a parametric model for an extended Kalman filter. The extended Kalman filter estimates the position, velocity, and mass of the meteoroid body throughout its flight, and quantitatively models uncertainties. Uncertainties have not previously been modeled so explicitly and are essential for determining fall distributions for potential meteorites. This two-step method aims to automate the process of mass determination for application to any trajectory data set and has been applied to observations of the Bunburra Rockhole fireball. The new method naturally handles noisy raw data. Initial and terminal bright flight mass results are consistent with other works based on the established photometric method and cosmic ray analysis. A full analysis of fragmentation and the variability in the heat-transfer coefficient will be explored in future versions of the model.
- Published
- 2015
- Full Text
- View/download PDF
42. Geochemistry and chronology of the Bunburra Rockhole ungrouped achondrite
- Author
-
Martin C. Towner, Gregory A. Brennecka, Philip A. Bland, Meenakshi Wadhwa, L. J. Spivak-Birndorf, Audrey Bouvier, Gretchen Benedix, Pavel Spurný, Kieren T. Howard, Samantha J. Hammond, and Nick Rogers
- Subjects
Isochron ,Radiogenic nuclide ,Extinct radionuclide ,Geochemistry ,Pyroxene ,engineering.material ,Geophysics ,Meteorite ,Space and Planetary Science ,engineering ,Plagioclase ,Achondrite ,Geology ,Petrogenesis - Abstract
Bunburra Rockhole is a unique basaltic achondrite that has many mineralogical and petrographic characteristics in common with the noncumulate eucrites, but differs in its oxygen isotope composition. Here, we report a study of the mineralogy, petrology, geochemistry, and chronology of Bunburra Rockhole to better understand the petrogenesis of this meteorite and compare it to the eucrites. The geochemistry of bulk samples and of pyroxene, plagioclase, and Ca-phosphate in Bunburra Rockhole is similar to that of typical noncumulate eucrites. Chronological data for Bunburra Rockhole indicate early formation, followed by slow cooling and perhaps multiple subsequent heating events, which is also similar to some noncumulate eucrites. The 26 Al- 26 Mg extinct radionuclide chronometer was reset in Bunburra Rockhole after the complete decay of 26 Al, but a slight excess in the radiogenic 26 Mg in a bulk sample allows the determination of a model 26 Al- 26 Mg age that suggests formation of the parent melt for this meteorite from its source magma within the first ~3 Ma of the beginning of the solar system. The 207 Pb- 206 Pb absolute chronometer is also disturbed in Bunburra Rockhole minerals, but a whole-rock isochron provides a re-equilibration age of ~4.1 Ga, most likely caused by impact heating. The mineralogy, geochemistry, and chronology of Bunburra Rockhole demonstrate the similarities of this achondrite to the eucrites, and suggest that it formed from a parent melt with a composition similar to that for noncumulate eucrites and subsequently experienced a thermal history and evolution comparable to that of eucritic basalts. This implies the formation of multiple differentiated parent bodies in the early solar system that had nearly identical bulk elemental compositions and petrogenetic histories, but different oxygen isotope compositions inherited from the solar nebula.
- Published
- 2015
- Full Text
- View/download PDF
43. Corrigendum: Probing the early stages of shock-induced chondritic meteorite formation at the mesoscale
- Author
-
David J. Chapman, Gareth S. Collins, Alexander Rack, Daniel E. Eakins, Michael E. Rutherford, Jack R.W. Patten, James G. Derrick, Philip A. Bland, and Science and Technology Facilities Council (STFC)
- Subjects
Multidisciplinary ,Meteorite ,Beamline ,010308 nuclear & particles physics ,0103 physical sciences ,Mesoscale meteorology ,Astronomy ,010306 general physics ,01 natural sciences ,Corrigenda ,Geology ,Storage ring ,Shock (mechanics) - Abstract
Chondritic meteorites are fragments of asteroids, the building blocks of planets, that retain a record of primordial processes. Important in their early evolution was impact-driven lithification, where a porous mixture of millimetre-scale chondrule inclusions and sub-micrometre dust was compacted into rock. In this Article, the shock compression of analogue precursor chondrite material was probed using state of the art dynamic X-ray radiography. Spatially-resolved shock and particle velocities, and shock front thicknesses were extracted directly from the radiographs, representing a greatly enhanced scope of data than could be measured in surface-based studies. A statistical interpretation of the measured velocities showed that mean values were in good agreement with those predicted using continuum-level modelling and mixture theory. However, the distribution and evolution of wave velocities and wavefront thicknesses were observed to be intimately linked to the mesoscopic structure of the sample. This Article provides the first detailed experimental insight into the distribution of extreme states within a shocked powder mixture, and represents the first mesoscopic validation of leading theories concerning the variation in extreme pressure-temperature states during the formation of primordial planetary bodies.
- Published
- 2017
44. Giant convecting mud balls of the early solar system
- Author
-
B. J. Travis and Philip A. Bland
- Subjects
Solar System ,education.field_of_study ,Multidisciplinary ,Astronomy ,Population ,SciAdv r-articles ,Chondrule ,010502 geochemistry & geophysics ,01 natural sciences ,Astrobiology ,Meteorite ,13. Climate action ,Chondrite ,Asteroid ,0103 physical sciences ,Terrestrial planet ,education ,010303 astronomy & astrophysics ,Lithification ,Research Articles ,Research Article ,0105 earth and related environmental sciences - Abstract
Primitive meteorites may have come from objects that were once an unconsolidated mixture of mud and clasts., Carbonaceous asteroids may have been the precursors to the terrestrial planets, yet despite their importance, numerous attempts to model their early solar system geological history have not converged on a solution. The assumption has been that hydrothermal alteration was occurring in rocky asteroids with material properties similar to meteorites. However, these bodies would have accreted as a high-porosity aggregate of igneous clasts (chondrules) and fine-grained primordial dust, with ice filling much of the pore space. Short-lived radionuclides melted the ice, and aqueous alteration of anhydrous minerals followed. However, at the moment when the ice melted, no geological process had acted to lithify this material. It would have been a mud, rather than a rock. We tested the effect of removing the assumption of lithification. We find that if the body accretes unsorted chondrules, then large-scale mud convection is capable of producing a size-sorted chondrule population (if the body accretes an aerodynamically sorted chondrule population, then no further sorting occurs). Mud convection both moderates internal temperature and reduces variation in temperature throughout the object. As the system is thoroughly mixed, soluble elements are not fractionated, preserving primitive chemistry. Isotopic and redox heterogeneity in secondary phases over short length scales is expected, as individual particles experience a range of temperature and water-rock histories until they are brought together in their final configuration at the end of convection. These results are consistent with observations from aqueously altered meteorites (CI and CM chondrites) and spectra of primitive asteroids. The “mudball” model appears to be a general solution: Bodies spanning a ×1000 mass range show similar behavior.
- Published
- 2017
- Full Text
- View/download PDF
45. Bunburra Rockhole: Exploring the geology of a new differentiated asteroid
- Author
-
Jon M. Friedrich, Stanley A. Mertzman, David W. Mittlefehldt, Philip A. Bland, Qing-Zhu Yin, Matthew E. Sanborn, Richard C. Greenwood, Grace C. Perrotta, A. W. R. Bevan, Martin C. Towner, Gretchen Benedix, and Ian A. Franchi
- Subjects
Eucrite ,Basalt ,Solar System ,Geochemistry ,Trace element ,010502 geochemistry & geophysics ,01 natural sciences ,Isotopes of oxygen ,Parent body ,Astrobiology ,Meteorite ,Geochemistry and Petrology ,Asteroid ,0103 physical sciences ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
Bunburra Rockhole is the first recovered meteorite of the Desert Fireball Network. We expanded a bulk chemical study of the Bunburra Rockhole meteorite to include major, minor and trace element analyses, as well as oxygen and chromium isotopes, in several different pieces of the meteorite. This was to determine the extent of chemical heterogeneity and constrain the origin of the meteorite. Minor and trace element analyses in all pieces are exactly on the basaltic eucrite trend. Major element analyses show a slight deviation from basaltic eucrite compositions, but not in any systematic pattern. New oxygen isotope analyses on 23 pieces of Bunburra Rockhole shows large variation in both δ17O and δ18O, and both are well outside the HED parent body fractionation line. We present the first Cr isotope results of this rock, which are also distinct from HEDs. Detailed computed tomographic scanning and back-scattered electron mapping do not indicate the presence of any other meteoritic contaminant (contamination is also unlikely based on trace element chemistry). We therefore conclude that Bunburra Rockhole represents a sample of a new differentiated asteroid, one that may have more variable oxygen isotopic compositions than 4 Vesta. The fact that Bunburra Rockhole chemistry falls on the eucrite trend perhaps suggests that multiple objects with basaltic crusts accreted in a similar region of the Solar System.
- Published
- 2017
46. A geochemical study of the winonaites: Evidence for limited partial melting and constraints on the precursor composition
- Author
-
A. C. Hunt, Katharina Kreissig, Philip A. Bland, Mark Rehkämper, Gretchen Benedix, Stanislav Strekopytov, Samantha J. Hammond, and Science and Technology Facilities Council (STFC)
- Subjects
Geochemistry & Geophysics ,FORSTERITE CHONDRITES ,010504 meteorology & atmospheric sciences ,Primitive achondrite ,Geochemistry ,Mineralogy ,Precursor material ,CHEMICAL-ANALYSES ,010502 geochemistry & geophysics ,01 natural sciences ,Parent body ,LODRANITE PARENT BODY ,Metal-silicate separation ,SOLAR-SYSTEM ,chemistry.chemical_compound ,ACHONDRITES ,Geochemistry and Petrology ,Chondrite ,IAB iron meteorite ,ICP-MS ,0402 Geochemistry ,Achondrite ,0105 earth and related environmental sciences ,IAB IRON-METEORITES ,Science & Technology ,Partial melting ,Winonaite ,Silicate ,EVOLUTION ,SILICATE INCLUSIONS ,OXYGEN-ISOTOPE ,STONY METEORITES ,chemistry ,Meteorite ,0403 Geology ,Physical Sciences ,Geology - Abstract
The winonaites are primitive achondrites which are associated with the IAB iron meteorites. Textural evidence implies heating to at least the Fe, Ni–FeS cotectic, but previous geochemical studies are ambiguous about the extent of silicate melting in these samples. Oxygen isotope evidence indicates that the precursor material may be related to the carbonaceous chondrites. Here we analysed a suite of winonaites for modal mineralogy and bulk major- and trace-element chemistry in order to assess the extent of thermal processing as well as constrain the precursor composition of the winonaite-IAB parent asteroid.\ud \ud Modal mineralogy and geochemical data are presented for eight winonaites. Textural analysis reveals that, for our sub-set of samples, all except the most primitive winonaite (Northwest Africa 1463) reached the Fe, Ni–FeS cotectic. However, only one (Tierra Blanca) shows geochemical evidence for silicate melting processes. Tierra Blanca is interpreted as a residue of small-degree silicate melting. Our sample of Winona shows geochemical evidence for extensive terrestrial weathering. All other winonaites studied here (Fortuna, Queen Alexander Range 94535, Hammadah al Hamra 193, Pontlyfni and NWA 1463) have chondritic major-element ratios and flat CI-normalised bulk rare-earth element patterns, suggesting that most of the winonaites did not reach the silicate melting temperature. The majority of winonaites were therefore heated to a narrow temperature range of between ∼1220 (the Fe, Ni–FeS cotectic temperature) and ∼1370 K (the basaltic partial melting temperature). Silicate inclusions in the IAB irons demonstrate partial melting did occur in some parts of the parent body (Ruzicka and Hutson, 2010), thereby implying heterogeneous heat distribution within this asteroid. Together, this indicates that melting was the result of internal heating by short-lived radionuclides. The brecciated nature of the winonaites suggests that the parent body was later disrupted by a catastrophic impact, which allowed the preservation of the largely unmelted winonaites.\ud \ud Despite major-element similarities to both ordinary and enstatite chondrites, trace-element analysis suggests the winonaite parent body had a carbonaceous chondrite-like precursor composition. The parent body of the winonaites was volatile-depleted relative to CI, but enriched compared to the other carbonaceous classes. The closest match are the CM chondrites; however, the specific precursor is not sampled in current meteorite collections.
- Published
- 2017
47. Halogen and Cl isotopic systematics in Martian phosphates: Implications for the Cl cycle and surface halogen reservoirs on Mars
- Author
-
Joshua F. Snape, Timm John, Jeremy J. Bellucci, Gretchen Benedix, Alexander A. Nemchin, Martin J. Whitehouse, and Philip A. Bland
- Subjects
Basalt ,Martian ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,Mineralogy ,Geokemi ,010502 geochemistry & geophysics ,01 natural sciences ,Perchlorate ,chemistry.chemical_compound ,Geophysics ,Geochemistry ,Meteorite ,chemistry ,Space and Planetary Science ,Geochemistry and Petrology ,Martian surface ,Halogen ,Breccia ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Earth (classical element) ,0105 earth and related environmental sciences - Abstract
The Cl isotopic compositions and halogen (Cl, F, Br, and I) abundances in phosphates from eight Martian meteorites, spanning most rock types and ages currently available, have been measured in situ by Secondary Ion Mass Spectrometry (SIMS). Likewise, the distribution of halogens has been documented by x-ray mapping. Halogen concentrations range over several orders of magnitude up to some of the largest concentrations yet measured in Martian samples or on the Martian surface, and the inter-element ratios are highly variable. Similarly, Cl isotope compositions exhibit a larger range than all pristine terrestrial igneous rocks. Phosphates in ancient (>4 Ga) meteorites (orthopyroxenite ALH 84001 and breccia NWA 7533) have positive δ 37 Cl anomalies (+1.1 to + 2.5 ‰ ). These samples also exhibit explicit whole rock and grain scale evidence for hydrothermal or aqueous activity. In contrast, the phosphates in the younger basaltic Shergottite meteorites ( δ 37 Cl anomalies (−0.2 to − 5.6 ‰ ). Phosphates with the largest negative δ 37 Cl anomalies display zonation in which the rims of the grains are enriched in all halogens and have significantly more negative δ 37 Cl anomalies suggestive of interaction with the surface of Mars during the latest stages of basalt crystallization. The phosphates with no textural, major element, or halogen enrichment evidence for mixing with this surface reservoir have an average δ 37 Cl of − 0.6 ‰ , supporting a similar initial Cl isotope composition for Mars, the Earth, and the Moon. Oxidation and reduction of chlorine are the only processes known to strongly fractionate Cl isotopes, both positively and negatively, and perchlorate has been detected in weight percent concentrations on the Martian surface. The age range and obvious mixing history of the phosphates studied here suggest perchlorate formation and halogen cycling via brines, which have been documented on the Martian surface, has been active throughout Martian history.
- Published
- 2017
48. Identification of a Minimoon Fireball
- Author
-
Hadrien A. R. Devillepoix, Robert M. Howie, Martin C. Towner, Benjamin A. D. Hartig, Trent Jansen-Sturgeon, Philip A. Bland, Eleanor K. Sansom, Patrick Shober, and Martin Cupak
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,010504 meteorology & atmospheric sciences ,Meteoroid ,Desert (particle physics) ,FOS: Physical sciences ,Astronomy ,Triangulation (social science) ,Astronomy and Astrophysics ,Large Synoptic Survey Telescope ,01 natural sciences ,Meteorite ,13. Climate action ,Space and Planetary Science ,0103 physical sciences ,Trajectory ,010303 astronomy & astrophysics ,Event (particle physics) ,Astrophysics - Earth and Planetary Astrophysics ,0105 earth and related environmental sciences ,Asteroid mining - Abstract
Objects gravitationally captured by the Earth-Moon system are commonly called temporarily captured orbiters (TCOs), natural Earth satellites, or minimoons. TCOs are a crucially important subpopulation of near-Earth objects (NEOs) to understand because they are the easiest targets for future sample-return, redirection, or asteroid mining missions. Only one TCO has ever been observed telescopically, 2006 RH 120, and it orbited Earth for about 11 months. Additionally, only one TCO fireball has ever been observed prior to this study. We present our observations of an extremely slow fireball (codename DN160822_03) with an initial velocity of around 11.0 km s-1 that was detected by six of the high-resolution digital fireball observatories located in the South Australian region of the Desert Fireball Network. Due to the inherent dynamics of the system, the probability of the meteoroid being temporarily captured before impact is extremely sensitive to its initial velocity. We examine the sensitivity of the fireball's orbital history to the chosen triangulation method. We use the numerical integrator REBOUND to assess particle histories and assess the statistical origin of DN160822_03. From our integrations we have found that the most probable capture time, velocity, semimajor axis, NEO group, and capture mechanism vary annually for this event. Most particles show that there is an increased capture probability during Earth's aphelion and perihelion. In the future, events like these may be detected ahead of time using telescopes like the Large Synoptic Survey Telescope, and the pre-atmospheric trajectory can be verified.
- Published
- 2019
- Full Text
- View/download PDF
49. Morphology and population of binary asteroid impact craters
- Author
-
Sahil Mannick, Gareth S. Collins, Philip A. Bland, and Katarina Miljković
- Subjects
education.field_of_study ,Near-Earth object ,Planetary surface ,Population ,Binary number ,Mars Exploration Program ,Astrobiology ,Geophysics ,Impact crater ,Space and Planetary Science ,Geochemistry and Petrology ,Asteroid ,Earth and Planetary Sciences (miscellaneous) ,education ,Earth (classical element) ,Geology - Abstract
Observational data show that in the Near Earth Asteroid (NEA) region 15% of asteroids are binary. However, the observed number of plausible doublet craters is 2–4% on Earth and 2–3% on Mars. This discrepancy between the percentage of binary asteroids and doublets on Earth and Mars may imply that not all binary systems form a clearly distinguishable doublet crater owing to insufficient separation between the binary components at the point of impact. We simulate the crater morphology formed in close binary asteroid impacts in a planetary environment and the range of possible crater morphologies includes: single (circular or elliptical) craters, overlapping (tear-drop or peanut shaped) craters, as well as clearly distinct, doublet craters. While the majority of binary asteroids impacting Earth or Mars should form a single, circular crater, about one in four are expected to form elongated or overlapping impact craters and one in six are expected to be doublets. This implies that doublets are formed in approximately 2% of all asteroid impacts on Earth and that elongated or overlapping binary impact craters are under-represented in the terrestrial crater record. The classification of a complete range of binary asteroid impact crater structures provides a template for binary asteroid impact crater morphologies, which can help in identifying planetary surface features observed by remote sensing.
- Published
- 2013
- Full Text
- View/download PDF
50. Utilizing functional genomics screening to identify potentially novel drug targets in cancer cell spheroid cultures
- Author
-
Andri Leonidou, Patty Wai, Gillian Farnie, Saira Khalique, Philip A. Bland, Barrie Peck, Frances Daley, Rachael Natrajan, and Eamonn Morrison
- Subjects
0301 basic medicine ,tumor ,Cancer Research ,Microenvironment ,Class I Phosphatidylinositol 3-Kinases ,Receptor, ErbB-2 ,General Chemical Engineering ,Antineoplastic Agents ,Genomics ,Computational biology ,Bioinformatics ,medicine.disease_cause ,General Biochemistry, Genetics and Molecular Biology ,Phosphatidylinositol 3-Kinases ,03 medical and health sciences ,In vivo ,Cell Line, Tumor ,Neoplasms ,Spheroids, Cellular ,SiRNA ,medicine ,Humans ,Issue 118 ,Epidermal growth factor receptor ,Tumor ,General Immunology and Microbiology ,biology ,Functional ,Manchester Cancer Research Centre ,General Neuroscience ,ResearchInstitutes_Networks_Beacons/mcrc ,Cancer ,medicine.disease ,microenvironment ,030104 developmental biology ,Spheroid ,spheroid ,Cell culture ,siRNA ,Cancer cell ,biology.protein ,Carcinogenesis ,Functional genomics - Abstract
The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery of the next generation of novel drug targets. It is becoming apparent that more complex models of cancer are required to fully appreciate the contributing factors that drive tumorigenesis in vivo and increase the efficacy of novel therapies that make the transition from preclinical models to clinical trials. Here we present a methodology for generating uniform and reproducible tumor spheroids that can be subjected to siRNA functional screening. These spheroids display many characteristics that are found in solid tumors that are not present in traditional two-dimension culture. We show that several commonly used breast cancer cell lines are amenable to this protocol. Furthermore, we provide proof-of-principle data utilizing the breast cancer cell line BT474, confirming their dependency on amplification of the epidermal growth factor receptor HER2 and mutation of phosphatidylinositol-4,5-biphosphate 3-kinase (PIK3CA) when grown as tumor spheroids. Finally, we are able to further investigate and confirm the spatial impact of these dependencies using immunohistochemistry.
- Published
- 2016
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.