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1. SN 2023ixf in Messier 101: Photo-ionization of Dense, Close-in Circumstellar Material in a Nearby Type II Supernova

Author

W. V. Jacobson-Galán, L. Dessart, R. Margutti, R. Chornock, R. J. Foley, C. D. Kilpatrick, D. O. Jones, K. Taggart, C. R. Angus, S. Bhattacharjee, L. A. Braff, D. Brethauer, A. J. Burgasser, F. Cao, C. M. Carlile, K. C. Chambers, D. A. Coulter, E. Dominguez-Ruiz, C. B. Dickinson, T. de Boer, A. Gagliano, C. Gall, H. Gao, E. L. Gates, S. Gomez, M. Guolo, M. R. J. Halford, J. Hjorth, M. E. Huber, M. N. Johnson, P. R. Karpoor, T. Laskar, N LeBaron, Z. Li, Y. Lin, S. D. Loch, P. D. Lynam, E. A. Magnier, P. Maloney, D. J. Matthews, M. McDonald, H.-Y. Miao, D. Milisavljevic, Y.-C. Pan, S. Pradyumna, C. L. Ransome, J. M. Rees, A. Rest, C. Rojas-Bravo, N. R. Sandford, L. Sandoval Ascencio, S. Sanjaripour, A. Savino, H. Sears, N. Sharei, S. J. Smartt, E. R. Softich, C. A. Theissen, S. Tinyanont, H. Tohfa, V. A. Villar, Q. Wang, R. J. Wainscoat, A. L. Westerling, E. Wiston, M. A. Wozniak, S. K. Yadavalli, and Y. Zenati

Subjects
Core-collapse supernovae, Circumstellar matter, Red supergiant stars, Sky surveys, Astrophysics, QB460-466
Abstract

We present UV and/or optical observations and models of SN 2023ixf, a type II supernova (SN) located in Messier 101 at 6.9 Mpc. Early time ( flash ) spectroscopy of SN 2023ixf, obtained primarily at Lick Observatory, reveals emission lines of H i , He i/ii , C iv , and N iii/iv/v with a narrow core and broad, symmetric wings arising from the photoionization of dense, close-in circumstellar material (CSM) located around the progenitor star prior to shock breakout. These electron-scattering broadened line profiles persist for ∼8 days with respect to first light, at which time Doppler broadened the features from the fastest SN ejecta form, suggesting a reduction in CSM density at r ≳ 10 ^15 cm. The early time light curve of SN 2023ixf shows peak absolute magnitudes (e.g., M _u = −18.6 mag, M _g = −18.4 mag) that are ≳2 mag brighter than typical type II SNe, this photometric boost also being consistent with the shock power supplied from CSM interaction. Comparison of SN 2023ixf to a grid of light-curve and multiepoch spectral models from the non-LTE radiative transfer code CMFGEN and the radiation-hydrodynamics code HERACLES suggests dense, solar-metallicity CSM confined to r = (0.5–1) × 10 ^15 cm, and a progenitor mass-loss rate of $\dot{M}={10}^{-2}\,{M}_{\odot }$ yr ^−1 . For the assumed progenitor wind velocity of v _w = 50 km s ^−1 , this corresponds to enhanced mass loss (i.e., superwind phase) during the last ∼3–6 yr before explosion.

Published
2023
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2. Abstracts of papers Pharmacological Meeting

Author

W. A. Bax, P. R. Saxena, Gerreke Ph. Biewenga, Jan Jong, Aalt Bast, Pauline G. M. Bloemen, Maria C. Tweel, Paul A. J. Henricks, Ferdi Engels, Frans P. Nijkamp, H. E. Molewijk, A. M. Poel, B. Olivier, M. R. Briejer, J. A. J. Schuurkes, L. M. A. Akkermans, T. A. Bruning, M. G. C. Hendriks, P. C. Chang, E. A. P. Kuypers, P. A. Zwieten, S. L. T. Cappendijk, R. Vries, M. R. Dzoljic, J. A. Bouwknecht, F. R. L. Crijns, M. S. P. Huijberts, H. A. J. Struijker Boudier, A. C. Nieuwenhuijzen Kruzeman, B. H. R. Wolffenbuttel, L. M. Lannov, A. H. J. Danser, R. G. Schoemakef, M. A. D. H. Schalekamp, Xiao Y. Du, Regien G. Schoemaker, Pramod R. Saxena, E. A. Dubois, H. D. Batink, M. Pfaffendorf, E. A. Roven, I. M. Garrelds, C. Graaf-in 't Veld, F. J. Ziilstra, A. P. H. Jansen, R. Gerth Wijk, B. C. G. Gho, R. G. Schoemaker, C. v. d. Lee, H. S. Sharma, P. D. Verdouw, L. Groenink, J. Gugten, T. J. J. Zethof, P. Hasselaar, J. W. C. M. Jansen, J. J. J. Giezen, G. H. Dreteler, A. Hulkenberq, J. H. Reinders, G. P. Toorop, A. H. J. Herremans, T. H. Hijzen, J. L. Slangen, E. M. Hessel, A. J. M. Oosterhout, C. Hofstra, J. Garssen, H. Loveren, H. F. J. Savelkoul, F. P. Nijkamp, Thorwald Hol, Jan M. Ree, Berry M. Spruijt, B. C. P. Hüsken, P. A. Zwieren, E. A. J. Kalkman, K. L. Kam, C. W. Keuzenkamp-Jansen, R. A. Abreu, J. P. M. Bökkerink, M. A. H. Heijden, J. M. F. Trijbels, A. D. Kraneveld, T. L. Buckley, Y. Schaik, A. Sj. Koster, R. A. A. Mathôt, B. C. F. M. Aarsen, M. W. E. Langemeijer, A. P. Ijzerman, M. Danhof, Inqe C. M. Mohede, Antoon J. M. Oosterhout, M. Monshouwer, R. F. Witkamp, S. M. Nijmeijer, A. S. J. P. A. M. Miert, J. Oosting, B. J. A. Janssen, A. J. Pijl, A. C. Wal, M. -J. Mathy, W. M. Pruimboom, A. P. M. Dijk, C. J. A. M. Tak, I. L. Bonta, J. H. P. Wilson, D. J. Bac, F. J. Zijlstra, G. Sadeghi Hashjin, G. Folkerts, P. A. J. Henricks, R. E. Santing, Y. Pasman, C. G. Olymulder, A. F. Roffel, J. Zaaqsma, H. Meurs, Heleen Scheerens, Theresa L. Buckley, Henk Loveren, H. Sipma, M. Duin, A. Hertog, A. Nelemans, J. Smit, R. P. Coppes, A. Geurtsen, J. Zaagsma, M. J. Smit, R. Leurs, A. Bast, H. Timmerman, F. R. M. Stassen, J. G. R. Mey, R. E. J. Berge, Guno H. K. Tjon, Taco J. Vries, Eric Ronken, François Hogenboom, George Warden, Arie H. Mulder, Anton N. M. Schoffelmeer, P. Bergen, J. A. Kleline, P. M. L. Janssen, J. G. M. Vaart, C. M. Kasbergen, D. H. G. Versteeg, D. J. Wildt, M. J. Velde, F. Engels, C. Berg, W. Vleeming, J. G. C. Amsterdam, J. Werner, L. Zee, A. Hertoe, E. Marcel Gelderen, Hendrik J. Agteresch, Emile L. E. Bruijne, J. P. Kats, L. M. A. Sassen, P. J. J. Admiraal, P. P. Verdouw, F. L. Muiswinkel, H. W. M. Steinhusch, B. Drukarch, J. C. Sloof, J. Vente, L. J. M. J. Vanderschuren, J. M. Ree, P. Verkade, A. J. Verkleij, W. H. Gispen, A. B. Oestreicher, R. J. Vermeulen, C. Goosen, E. Ch. Wolters, J. C. Stoof, V. A. M. Vincent, A. N. M. Schoffelmeer, H. W. M. Steinbush, F. Berlcenbosch, Hans-Peter Voss, David Donnell, J. P. M. Wesselman, E. VanBavel, J. A. E. Spaan, W. M. Zeilmaker, G. A. E. Klooster, G. J. M. J. Horbach, J. Zhang, J. S. Zhang, and J. C. A. Meet

Subjects
Pharmacology, Pharmaceutical Science, Pharmacology (medical), Pharmacy, General Medicine, Toxicology
Published
1993
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3. Improved annotation of the domestic pig genome through integration of Iso-Seq and RNA-seq data

Author

H. Beiki, H. Liu, J. Huang, N. Manchanda, D. Nonneman, T. P. L. Smith, J. M. Reecy, and C. K. Tuggle

Subjects
Porcine, Transcriptome sequencing, PacBio, Iso-seq, Single molecule long read sequencing, RNA-seq, Biotechnology, TP248.13-248.65, Genetics, QH426-470
Abstract

Abstract Background Our understanding of the pig transcriptome is limited. RNA transcript diversity among nine tissues was assessed using poly(A) selected single-molecule long-read isoform sequencing (Iso-seq) and Illumina RNA sequencing (RNA-seq) from a single White cross-bred pig. Results Across tissues, a total of 67,746 unique transcripts were observed, including 60.5% predicted protein-coding, 36.2% long non-coding RNA and 3.3% nonsense-mediated decay transcripts. On average, 90% of the splice junctions were supported by RNA-seq within tissue. A large proportion (80%) represented novel transcripts, mostly produced by known protein-coding genes (70%), while 17% corresponded to novel genes. On average, four transcripts per known gene (tpg) were identified; an increase over current EBI (1.9 tpg) and NCBI (2.9 tpg) annotations and closer to the number reported in human genome (4.2 tpg). Our new pig genome annotation extended more than 6000 known gene borders (5′ end extension, 3′ end extension, or both) compared to EBI or NCBI annotations. We validated a large proportion of these extensions by independent pig poly(A) selected 3′-RNA-seq data, or human FANTOM5 Cap Analysis of Gene Expression data. Further, we detected 10,465 novel genes (81% non-coding) not reported in current pig genome annotations. More than 80% of these novel genes had transcripts detected in > 1 tissue. In addition, more than 80% of novel intergenic genes with at least one transcript detected in liver tissue had H3K4me3 or H3K36me3 peaks mapping to their promoter and gene body, respectively, in independent liver chromatin immunoprecipitation data. Conclusions These validated results show significant improvement over current pig genome annotations.

Published
2019
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4. Genome-wide association study for response to vaccination in Angus calves1

Author

L. M. Kramer, M. S. Mayes, E. D. Downey, R. G. Tait, A. Woolums, C. Chase, and J. M. Reecy

Subjects
Accuracy, Beef cattle, Bovine respiratory disease complex, Genome-wide association study, Heritability, Immune response, Genetics, QH426-470
Abstract

Abstract Background Bovine respiratory disease complex (BRDC) is one of the most important sources of loss within the beef cattle industry in the USA. Steps have been taken to reduce the incidence of BRDC through vaccination. Despite the effectiveness of vaccines, large proportions of cattle still experience morbidity and mortality. Identification of genomic regions that are associated with variation in response to vaccination would allow for the selection of individuals genetically predisposed to respond to vaccination based on specific markers, while heritability and accuracy estimates would help facilitate genomic selection. This in turn may lead to selection for beef cattle herds that may have lower incidence rate of BRDC after vaccination. This study utilizes an Angus herd of more than 2000 head of cattle to identify these regions of association. Results Genome wide association studies were performed for viral neutralization antibody level and response to vaccination traits against four different viruses associated with BRDC: bovine viral diarrhea virus 1 and 2 (BVDV1 and BVDV2), bovine respiratory syncytial virus (BRSV), and bovine herpesvirus (BHV1). A total of six 1-Mb windows were associated with greater than 1% of the genetic variance for the analyzed vaccination response traits. Heritabilities ranged from 0.08 to 0.21 and prediction accuracy ranged from 0.01 to 0.33 across 7 different vaccination traits. Conclusions Although six 1-Mb windows were identified as associated with 1% or greater genetic variance for viral neutralization antibody level and response to vaccination traits, few genes around these windows could readily be considered candidates. This indicates the need for further functional genomic annotation, as these regions appear to be gene deserts. Traits ranged from lowly to moderately heritable, which indicated the potential for selection of individuals that are genetically pre-disposed to respond to vaccination. The relatively low amount of genetic variance accounted for by any 1-Mb window indicated that viral neutralization antibody level and response to vaccination traits are polygenic in nature. Selection for these traits is possible, but likely to be slow due to the low heritabilities and absence of markers with high genetic variation associated with them.

Published
2019
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5. Fast time response measurements of particle size distributions in the 3–60 nm size range with the nucleation mode aerosol size spectrometer

Author

C. Williamson, A. Kupc, J. Wilson, D. W. Gesler, J. M. Reeves, F. Erdesz, R. McLaughlin, and C. A. Brock

Subjects
Environmental engineering, TA170-171, Earthwork. Foundations, TA715-787
Abstract

Earth's radiation budget is affected by new particle formation (NPF) and the growth of these nanometre-scale particles to larger sizes where they can directly scatter light or act as cloud condensation nuclei (CCN). Large uncertainties remain in the magnitude and spatiotemporal distribution of nucleation (less than 10 nm diameter) and Aitken (10–60 nm diameter) mode particles. Acquiring size-distribution measurements of these particles over large regions of the free troposphere is most easily accomplished with research aircraft.We report on the design and performance of an airborne instrument, the nucleation mode aerosol size spectrometer (NMASS), which provides size-selected aerosol concentration measurements that can be differenced to identify aerosol properties and processes or inverted to obtain a full size distribution between 3 and 60 nm. By maintaining constant downstream pressure the instrument operates reliably over a large range of ambient pressures and during rapid changes in altitude, making it ideal for aircraft measurements from the boundary layer to the stratosphere.We describe the modifications, operating principles, extensive calibrations, and laboratory and in-flight performance of two NMASS instruments operated in parallel as a 10-channel battery of condensation particle counters (CPCs) in the NASA Atmospheric Tomography Mission (ATom) to investigate NPF and growth to cloud-active sizes in the remote free troposphere. An inversion technique to obtain size distributions from the discrete concentrations of each NMASS channel is described and evaluated.Concentrations measured by the two NMASS instruments flying in parallel are self-consistent and also consistent with measurements made with an optical particle counter. Extensive laboratory calibrations with a range of particle sizes and compositions show repeatability of the response function of the instrument to within 5–8 % and no sensitivity in sizing performance to particle composition. Particle number, surface area, and volume concentrations from the data inversion are determined to better than 20 % for typical particle size distributions. The excellent performance of the NMASS systems provides a strong analytical foundation to explore NPF around the globe in the ATom dataset.

Published
2018
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6. BrO and inferred Bry profiles over the western Pacific: relevance of inorganic bromine sources and a Bry minimum in the aged tropical tropopause layer

Author

T. K. Koenig, R. Volkamer, S. Baidar, B. Dix, S. Wang, D. C. Anderson, R. J. Salawitch, P. A. Wales, C. A. Cuevas, R. P. Fernandez, A. Saiz-Lopez, M. J. Evans, T. Sherwen, D. J. Jacob, J. Schmidt, D. Kinnison, J.-F. Lamarque, E. C. Apel, J. C. Bresch, T. Campos, F. M. Flocke, S. R. Hall, S. B. Honomichl, R. Hornbrook, J. B. Jensen, R. Lueb, D. D. Montzka, L. L. Pan, J. M. Reeves, S. M. Schauffler, K. Ullmann, A. J. Weinheimer, E. L. Atlas, V. Donets, M. A. Navarro, D. Riemer, N. J. Blake, D. Chen, L. G. Huey, D. J. Tanner, T. F. Hanisco, and G. M. Wolfe

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic bromine (Bry) over the tropical western Pacific Ocean (tWPO) during the CONTRAST field campaign (January–February 2014). The observed BrO and inferred Bry profiles peak in the marine boundary layer (MBL), suggesting the need for a bromine source from sea-salt aerosol (SSA), in addition to organic bromine (CBry). Both profiles are found to be C-shaped with local maxima in the upper free troposphere (FT). The median tropospheric BrO vertical column density (VCD) was measured as 1.6×1013 molec cm−2, compared to model predictions of 0.9×1013 molec cm−2 in GEOS-Chem (CBry but no SSA source), 0.4×1013 molec cm−2 in CAM-Chem (CBry and SSA), and 2.1×1013 molec cm−2 in GEOS-Chem (CBry and SSA). Neither global model fully captures the C-shape of the Bry profile. A local Bry maximum of 3.6 ppt (2.9–4.4 ppt; 95 % confidence interval, CI) is inferred between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective tropical tropopause layer (TTL) to the aged TTL, gas-phase Bry decreases from the convective TTL to the aged TTL. Analysis of gas-phase Bry against multiple tracers (CFC-11, H2O ∕ O3 ratio, and potential temperature) reveals a Bry minimum of 2.7 ppt (2.3–3.1 ppt; 95 % CI) in the aged TTL, which agrees closely with a stratospheric injection of 2.6 ± 0.6 ppt of inorganic Bry (estimated from CFC-11 correlations), and is remarkably insensitive to assumptions about heterogeneous chemistry. Bry increases to 6.3 ppt (5.6–7.0 ppt; 95 % CI) in the stratospheric "middleworld" and 6.9 ppt (6.5–7.3 ppt; 95 % CI) in the stratospheric "overworld". The local Bry minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-Chem, and suggests a more complex partitioning of gas-phase and aerosol Bry species than previously recognized. Our data provide corroborating evidence that inorganic bromine sources (e.g., SSA-derived gas-phase Bry) are needed to explain the gas-phase Bry budget in the upper free troposphere and TTL. They are also consistent with observations of significant bromide in Upper Troposphere–Lower Stratosphere aerosols. The total Bry budget in the TTL is currently not closed, because of the lack of concurrent quantitative measurements of gas-phase Bry species (i.e., BrO, HOBr, HBr, etc.) and aerosol bromide. Such simultaneous measurements are needed to (1) quantify SSA-derived Bry in the upper FT, (2) test Bry partitioning, and possibly explain the gas-phase Bry minimum in the aged TTL, (3) constrain heterogeneous reaction rates of bromine, and (4) account for all of the sources of Bry to the lower stratosphere.

Published
2017
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7. The environmental and evolutionary history of Lake Ohrid (FYROM/Albania): interim results from the SCOPSCO deep drilling project

Author

B. Wagner, T. Wilke, A. Francke, C. Albrecht, H. Baumgarten, A. Bertini, N. Combourieu-Nebout, A. Cvetkoska, M. D'Addabbo, T. H. Donders, K. Föller, B. Giaccio, A. Grazhdani, T. Hauffe, J. Holtvoeth, S. Joannin, E. Jovanovska, J. Just, K. Kouli, A. Koutsodendris, S. Krastel, J. H. Lacey, N. Leicher, M. J. Leng, Z. Levkov, K. Lindhorst, A. Masi, A. M. Mercuri, S. Nomade, N. Nowaczyk, K. Panagiotopoulos, O. Peyron, J. M. Reed, E. Regattieri, L. Sadori, L. Sagnotti, B. Stelbrink, R. Sulpizio, S. Tofilovska, P. Torri, H. Vogel, T. Wagner, F. Wagner-Cremer, G. A. Wolff, T. Wonik, G. Zanchetta, and X. S. Zhang

Subjects
Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract

This study reviews and synthesises existing information generated within the SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismotectonic history, (iii) volcanic activity and climate change in the central northern Mediterranean region, and (iv) the influence of major geological events on the evolution of its endemic species. The Ohrid basin formed by transtension during the Miocene, opened during the Pliocene and Pleistocene, and the lake established de novo in the still relatively narrow valley between 1.9 and 1.3 Ma. The lake history is recorded in a 584 m long sediment sequence, which was recovered within the framework of the International Continental Scientific Drilling Program (ICDP) from the central part (DEEP site) of the lake in spring 2013. To date, 54 tephra and cryptotephra horizons have been found in the upper 460 m of this sequence. Tephrochronology and tuning biogeochemical proxy data to orbital parameters revealed that the upper 247.8 m represent the last 637 kyr. The multi-proxy data set covering these 637 kyr indicates long-term variability. Some proxies show a change from generally cooler and wetter to drier and warmer glacial and interglacial periods around 300 ka. Short-term environmental change caused, for example, by tephra deposition or the climatic impact of millennial-scale Dansgaard–Oeschger and Heinrich events are superimposed on the long-term trends. Evolutionary studies on the extant fauna indicate that Lake Ohrid was not a refugial area for regional freshwater animals. This differs from the surrounding catchment, where the mountainous setting with relatively high water availability provided a refuge for temperate and montane trees during the relatively cold and dry glacial periods. Although Lake Ohrid experienced significant environmental change over the last 637 kyr, preliminary molecular data from extant microgastropod species do not indicate significant changes in diversification rate during this period. The reasons for this constant rate remain largely unknown, but a possible lack of environmentally induced extinction events in Lake Ohrid and/or the high resilience of the ecosystems may have played a role.

Published
2017
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8. Dual-plane PIV investigation of acoustically excited jets in a swirl nozzle

Author

G. S. Regunath, W. B. Zimmerman, and J. M. Rees

Subjects
Science, Physics, QC1-999, Geophysics. Cosmic physics, QC801-809
Abstract

A novel dual-plane dye laser particle image velocimetry (PIV) technique used to analyze helicity and energy dissipation in an unexcited turbulent swirling jet of pressurized cold air has established that regions within the flow field of the jet exhibiting high helicity are correlated regions of high turbulent kinetic energy dissipation. This PIV configuration provides estimates of all components of the velocity gradient tensor, facilitating calculation of the helicity from the vorticity components. Application of this novel dual-plane PIV technique is extended in this study to investigate helical structures in a turbulent swirling jet where the underlying shear flow is subjected to external acoustic sinusoidal forcing in a plane perpendicular to the central axis of the jet. It was found that acoustic excitation had a significant effect on the mean velocity profile parallel to the direction of the jet. The horizontal forcing resulted in the generation of vorticity that was skewed with a pitch that favored a distribution of angles around 90° with respect to the velocity vector. The distribution of the time-averaged helicity angle indicated organized helical activity, but such activity is not dominated by large-scale coherent structures of maximal helicity.

Published
2016
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9. Complexity of diatom response to Lateglacial and Holocene climate and environmental change in ancient, deep and oligotrophic Lake Ohrid (Macedonia and Albania)

Author

X. S. Zhang, J. M. Reed, J. H. Lacey, A. Francke, M. J. Leng, Z. Levkov, and B. Wagner

Subjects
Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract

Lake Ohrid (Macedonia and Albania) is a rare example of a deep, ancient Mediterranean lake and is a key site for palaeoclimate research in the northeastern Mediterranean region. This study conducts the analysis of diatoms as a proxy for Lateglacial and Holocene climate and environmental change in Lake Ohrid at a higher resolution than in previous studies. While Lake Ohrid has the potential to be sensitive to water temperature change, the data demonstrate a highly complex diatom response, probably comprising a direct response to temperature-induced lake productivity in some phases and an indirect response to temperature-related lake stratification or mixing and epilimnetic nutrient availability in others. The data also demonstrate the possible influence of physical limnological (e.g. the influence of wind stress on stratification or mixing) and chemical processes (e.g. the influence of catchment dynamics on nutrient input) in mediating the complex response of diatoms. During the Lateglacial (ca. 12 300–11 800 cal yr BP), the low-diversity dominance of hypolimnetic Cyclotella fottii indicates low lake productivity, linked to low water temperature. Although the subsequent slight increase in small, epilimnetic C. minuscula during the earliest Holocene (ca. 11 800–10 600 cal yr BP) suggests climate warming and enhanced stratification, diatom concentration remains as low as during the Lateglacial, suggesting that water temperature increase was muted across this major transition. The early Holocene (ca. 10 600–8200 cal yr BP) is characterised by a sustained increase in epilimnetic taxa, with mesotrophic C. ocellata indicating high water-temperature-induced productivity between ca. 10 600–10 200 cal yr BP and between ca. 9500–8200 cal yr BP and with C. minuscula in response to low nutrient availability in the epilimnion between ca. 10 200–9500 cal yr BP. During the middle Holocene (ca. 8200–2600 cal yr BP), when sedimentological and geochemical proxies provide evidence for maximum Holocene water temperature, anomalously low C. ocellata abundance is probably a response to epilimnetic nutrient limitation, almost mimicking the Lateglacial flora apart from the occurrence of mesotrophic Stephanodiscus transylvanicus in the hypolimnion. During the late Holocene (ca. 2600 cal yr BP–present), high abundance and fluctuating composition of epilimnetic taxa are probably a response more to enhanced anthropogenic nutrient input, particularly nitrogen enrichment, than to climate. Overall, the data indicate that previous assumptions concerning the linearity of diatom response in this deep, ancient lake are invalid, and multi-proxy analysis is essential to improve understanding of palaeolimnological dynamics in future research on the long, Quaternary sequence.

Published
2016
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10. HLA, AND THE RESPONSE TO TREATMENT WITH ?-TYPE ENDORPHINS IN SCHIZOPHRENIA

Author

W. M. A. Verhoeven, J. M. Ree, D. de Wied, Jon J. van Rood, and B. M. De Jongh

Subjects
medicine.medical_specialty, Paranoid schizophrenia, Immunology, HLA-C Antigens, Human leukocyte antigen, HLA-B15 Antigen, Biology, chemistry.chemical_compound, Antigen, HLA Antigens, Internal medicine, Genetics, medicine, HLA-B Antigens, Humans, Endorphins, Patient group, beta-Endorphin, gamma-Endorphin, medicine.disease, Response to treatment, Peptide Fragments, Endocrinology, chemistry, Schizophrenia
Abstract

In order to investigate whether genetic factors are involved in the response of schizophrenic patients to treatment with gamma-type endorphins, we typed 32 Dutch schizophrenic patients for the HLA-A, -B, -C and -DR antigens. The total patient group showed an increase of HLA-Bw4 and HLA-Cw1. A subgroup of 20 paranoid patients showed an increase of HLA-Cw1 and a significant heterogeneity for the HLA-C locus. In 16 patients who responded moderately or markedly to treatment with gamma-type endorphins, an increase of HLA-B15/Cw3 and a decrease of HLA-B17 were found as compared to 16 patients with no or a slight response. Moreover, HLA-B15 was particularly increased in those patients who responded markedly and remained free of psychotic symptoms for a period of at least 6 months after treatment with gamma-type endorphins (RR = 24.6, Puncorr. = 0.0015). Our results suggest that genetic factors coded for within the HLA region are associated with paranoid schizophrenia, and that HLA-B15/Cw3 is associated with a marked and prolonged response to treatment with gamma-type endorphins.

Published
1982
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11. The SCOPSCO drilling project recovers more than 1.2 million years of history from Lake Ohrid

Author

B. Wagner, T. Wilke, S. Krastel, G. Zanchetta, R. Sulpizio, K. Reicherter, M. J. Leng, A. Grazhdani, S. Trajanovski, A. Francke, K. Lindhorst, Z. Levkov, A. Cvetkoska, J. M. Reed, X. Zhang, J. H. Lacey, T. Wonik, H. Baumgarten, and H. Vogel

Subjects
Geology, QE1-996.5
Abstract

The Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project is an international research initiative to study the influence of major geological and environmental events on the biological evolution of lake taxa. SCOPSCO drilling campaigns were carried out in 2011 and 2013. In 2011 we used gravity and piston coring at one of the five proposed drill sites, and in 2013 we undertook deep drilling with the Deep Lake Drilling System (DLDS) of Drilling, Observation and Sampling of the Earth's Continental Crust (DOSECC). In April and May 2013, a total of 2100 m sediments were recovered from four drill sites with water depths ranging from 125 to 260 m. The maximum drill depth was 569 m below the lake floor in the centre of the lake. By retrieving overlapping sediment sequences, 95% of the sediment succession was recovered. Initial data from borehole logging, core logging and geochemical measurements indicate that the sediment succession covers >1.2 million years (Ma) in a quasi-continuous sequence. These early findings suggest that the record from Lake Ohrid will substantially improve the knowledge of long-term environmental change and short-term geological events in the northeastern Mediterranean region, which forms the basis for improving understanding of the influence of major geological and environmental events on the biological evolution of endemic species.

Published
2014
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12. In situ observations of new particle formation in the tropical upper troposphere: the role of clouds and the nucleation mechanism

Author

R. Weigel, S. Borrmann, J. Kazil, A. Minikin, A. Stohl, J. C. Wilson, J. M. Reeves, D. Kunkel, M. de Reus, W. Frey, E. R. Lovejoy, C. M. Volk, S. Viciani, F. D'Amato, C. Schiller, T. Peter, H. Schlager, F. Cairo, K. S. Law, G. N. Shur, G. V. Belyaev, and J. Curtius

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

New particle formation (NPF), which generates nucleation mode aerosol, was observed in the tropical Upper Troposphere (UT) and Tropical Tropopause Layer (TTL) by in situ airborne measurements over South America (January–March 2005), Australia (November–December 2005), West Africa (August 2006) and Central America (2004–2007). Particularly intense NPF was found at the bottom of the TTL. Measurements with a set of condensation particle counters (CPCs) with different dp50 (50% lower size detection efficiency diameter or "cut-off diameter") were conducted on board the M-55 Geophysica in the altitude range of 12.0–20.5 km and on board the DLR Falcon-20 at up to 11.5 km altitude. On board the NASA WB-57F size distributions were measured over Central America in the 4 to 1000 nm diameter range with a system of nucleation mode aerosol spectrometers. Nucleation mode particle concentrations (NNM) were derived from these measurements which allow for identifying many NPF events with NNM in the range of thousands of particles per cm3. Over Australia and West Africa, we identified NPF in the outflow of tropical convection, in particular of a Mesoscale Convective System (MCS). Newly formed particles with NNM > 1000 cm−3 were found to coexist with ice cloud particles (dp > 2 μm) as long as cloud particle concentrations remained below 2 cm−3. The occurrence of NPF within the upper troposphere and the TTL was generally confined within 340 K to 380 K potential temperature, but NPF was of particular strength between 350 K and 370 K (i.e. ~1–4 km below the cold point tropopause). Analyses of the aerosol volatility (at 250 °C) show that in the TTL on average 75–90% of the particles were volatile, compared to typically only 50% in the extra-tropical UT, indicative for the particles to mainly consist of H2SO4-H2O and possibly organic compounds. Along two flight segments over Central and South America (24 February 2005 and 7 August 2006, at 12.5 km altitude) in cloud free air, above thin cirrus, particularly high NNM were observed. Recent lifting had influenced the probed air masses, and NNM reached up to 16 000 particles cm−3 (ambient concentration). A sensitivity study using an aerosol model, which includes neutral and ion induced nucleation processes, simulates NNM in reasonable agreement with the in situ observations of clear-air NPF. Based on new, stringent multi-CPC criteria, our measurements corroborate the hypothesis that the tropical UT and the TTL are regions supplying freshly nucleated particles. Our findings narrow the altitude of the main source region to the bottom TTL, i.e. to the level of main tropical convection outflow, and, by means of measurements of carbon monoxide, they indicate the importance of anthropogenic emissions in NPF. After growth and/or coalescence the nucleation mode particles may act as cloud condensation nuclei in the tropical UT, or, upon ascent into the stratosphere, contribute to maintain the stratospheric background aerosol.

Published
2011
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13. The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate

Author

J. M. Reed, A. Cvetkoska, Z. Levkov, H. Vogel, and B. Wagner

Subjects
Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract

Lake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the Last Glacial, while setting up taxonomic protocols for future research. The results are outstanding in demonstrating the sensitivity of diatoms to climate change, providing proxy evidence for temperature change marked by glacial-interglacial shifts between the dominant planktonic taxa, Cyclotella fottii and C. ocellata, and exact correlation with geochemical proxies to mark the start of the Last Interglacial at ca. 130 ka. Importantly, diatoms show much stronger evidence in this site for warming during MIS3 than recorded in other productivity-related proxies, peaking at ca. 39 ka, prior to the extreme conditions of the Last Glacial maximum. In the light of the observed patterns, and from the results of analysis of early Holocene sediments from a second core, Lz1120, the lack of a response to Late Glacial and early Holocene warming from ca. 14.7–6.9 ka suggests the Co1202 sequence may be compromised during this phase. After ca. 7.4 ka, there is evidence for enhanced nutrient enrichment compared to the Last Interglacial, followed by a post-Medieval loss of diversity which is consistent with cooling, but not definitive. Taxonomically, morphological variability in C. fottii shows no clear trends linked to climate, but an intriguing change in central area morphology occurs after ca. 48.7 ka, coincident with a tephra layer. In contrast, C. ocellata shows morphological variation in the number of ocelli between interglacials, suggesting climatically-forced variation or evolutionary selection pressure. The application of a simple dissolution index does not track preservation quality very effectively, underlining the importance of diatom accumulation data in future studies.

Published
2010
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14. Steady-state aerosol distributions in the extra-tropical, lower stratosphere and the processes that maintain them

Author

J. C. Wilson, S.-H. Lee, J. M. Reeves, C. A. Brock, H. H. Jonsson, B. G. Lafleur, M. Loewenstein, J. Podolske, E. Atlas, K. Boering, G. Toon, D. Fahey, T. P. Bui, G. Diskin, and F. Moore

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Measurements of aerosol, N2O and OCS made in the Northern Hemisphere below 21 km altitude following the eruption of Pinatubo are presented and analyzed. After September 1999, the oxidation of OCS and sedimentation of particles in the extra-tropical overworld north of 45 N are found to maintain the aerosol in a steady state. This analysis empirically links precursor gas to aerosol abundance throughout this region. These processes are tracked with age-of-air which offers advantages over tracking as a function of latitude and altitude. In the extra-tropical, lowermost stratosphere, normalized volume distributions appear constant in time after the fall of 1999. Exchange with the troposphere is important in understanding aerosol evolution there. Size distributions of volcanically perturbed aerosol are included to distinguish between volcanic and non-volcanic conditions. This analysis suggests that model failures to correctly predict OCS and aerosol properties below 20 km in the Northern Hemisphere extra tropics result from inadequate descriptions of atmospheric circulation.

Published
2008

15. Long solitary internal waves in stable stratifications

Author

W. B. Zimmerman and J. M. Rees

Subjects
Science, Physics, QC1-999, Geophysics. Cosmic physics, QC801-809
Abstract

Observations of internal solitary waves over an antarctic ice shelf (Rees and Rottman, 1994) demonstrate that even large amplitude disturbances have wavelengths that are bounded by simple heuristic arguments following from the Scorer parameter based on linear theory for wave trapping. Classical weak nonlinear theories that have been applied to stable stratifications all begin with perturbations of simple long waves, with corrections for weak nonlinearity and dispersion resulting in nonlinear wave equations (Korteweg-deVries (KdV) or Benjamin-Davis-Ono) that admit localized propagating solutions. It is shown that these theories are apparently inappropriate when the Scorer parameter, which gives the lowest wavenumber that does not radiate vertically, is positive. In this paper, a new nonlinear evolution equation is derived for an arbitrary wave packet thus including one bounded below by the Scorer parameter. The new theory shows that solitary internal waves excited in high Richardson number waveguides are predicted to have a halfwidth inversely proportional to the Scorer parameter, in agreement with atmospheric observations. A localized analytic solution for the new wave equation is demonstrated, and its soliton-like properties are demonstrated by numerical simulation.

Published
2004

16. Exposed water ice on the nucleus of comet 67P/Churyumov-Gerasimenko

Author

Giancarlo Bellucci, Katrin Stephan, Yves Langevin, Sergio Fonti, G. Peter, Gianrico Filacchione, Ulrich Schade, G. P. Tozzi, Jacques Crovisier, Costanzo Federico, Eleonora Ammannito, M. I. Blecka, S. Jacquinod, Jean-Michel Reess, M. Cartacci, Michael R. Combi, Vito Mennella, Federico Tosi, Marcello Fulchignoni, Armando Blanco, Giuseppe Piccioni, Roberto Orosei, Bernard Schmitt, Andrea Longobardo, Giovanna Rinaldi, Ralf Jaumann, Vincenzo Orofino, Alessandra Migliorini, Andrea Raponi, Pierre Drossart, M. Combes, David Kappel, Mauro Ciarniello, D. Despan, Murthy S. Gudipati, C. Leyrat, T. Encrenaz, Ernesto Palomba, Andrea Cicchetti, Fabrizio Capaccioni, Michelangelo Formisano, Maria Teresa Capria, Romolo Politi, Dominique Bockelée-Morvan, Stefano Mottola, Enrico Flamini, Pierre Beck, L. Moroz, Gianfranco Magni, U. Fink, Eric Quirico, Fredric W. Taylor, Sonia Fornasier, J-Ph. Combe, F. Merlin, Jean-Pierre Bibring, N. Biver, M. C. De Sanctis, Florence Henry, Uri Carsenty, M. A. Barucci, Gabriele Arnold, Y. Hello, Patrick G. J. Irwin, R. W. Carlson, Wing-Huen Ip, E. Kuehrt, Kathrin Markus, Davide Grassi, S. Giuppi, Raffaella Noschese, Alessandro Frigeri, F. Mancarella, Stéphane Erard, Luigi Colangeli, Lydie Bonal, T. B. McCord, J. Benkhoff, D. Tiphene, Priscilla Cerroni, G., Filacchione, M. C., De Sancti, F., Capaccioni, A., Raponi, F., Tosi, M., Ciarniello, P., Cerroni, G., Piccioni, M. T., Capria, E., Palomba, G., Bellucci, S., Erard, D., Bockelee Morvan, C., Leyrat, G., Arnold, M. A., Barucci, M., Fulchignoni, B., Schmitt, E., Quirico, R., Jaumann, K., Stephan, A., Longobardo, V., Mennella, A., Migliorini, E., Ammannito, J., Benkhoff, J. P., Bibring, Blanco, Armando, M. I., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, M., Combi, J., Crovisier, P., Drossart, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, W. H., Ip, P., Irwin, E., Kuehrt, Y., Langevin, G., Magni, T., Mccord, L., Moroz, S., Mottola, Orofino, Vincenzo, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, P., Beck, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, M., Formisano, S., Fornasier, A., Frigeri, D., Grassi, M. S., Gudipati, D., Kappel, Mancarella, Francesca, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, J. M., Ree, R., Noschese, R., Politi, G., Peter, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Mécanique Textiles (LPMT), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), German Aerospace Center (DLR), Deutsches Zentrum für Luft- und Raumfahrt (DLR), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Capodimonte (OAC), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Instituto de Estudos Avançados (IEAV), Institut, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Dipartimento di Fisica, Università degli studi di Lecce, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Physics [Oxford], University of Oxford, Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], DLR Institute of Planetary Research, Department of Physics [Lecce], Università del Salento [Lecce], INAF - Osservatorio Astrofisico di Arcetri (OAA), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Alenia Aerospazio, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), JDS Uniphase/Cronos, USA, JDS Uniphase/Cronos, CNR-IASF, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Consiglio Nazionale delle Ricerche (CNR), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-ENSITM-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Polska Akademia Nauk (PAN), University of Oxford [Oxford], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Centre National de la Recherche Scientifique (CNRS), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), ENSITM-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 010504 meteorology & atmospheric sciences, Extraterrestrial Environment, Comet, Mineralogy, comet 67P, 01 natural sciences, water ice, Astrobiology, Diffusion, 0103 physical sciences, Rosetta, medicine, Diffusion (business), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Meteoroid, Spectrum Analysis, Ice, food and beverages, Meteoroids, VIRTIS, Debris, Asteroids, Grain growth, medicine.anatomical_structure, 13. Climate action, comets and Kuiper belt Early solar system, Gases, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Water vapor
Abstract

Although water vapour is the main species observed in the coma of comet 67P/Churyumov–Gerasimenko1, 2 and water is the major constituent of cometary nuclei3, 4, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far5, 6. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far7, 8, 9. The nucleus of 67P/Churyumov–Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material10. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations6, 7, 8, 9. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers6, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust10 is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov–Gerasimenko11, 12 is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet’s formation.

Published
2016
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17. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author

Gabriele Arnold, Maria Teresa Capria, Y. Hello, Kathrin Markus, Vincenzo Orofino, A. Semery, Romolo Politi, Stéphane Erard, Roberto Orosei, Robert W. Carlson, Davide Grassi, M. Combes, J. Crovisier, Gianfranco Magni, Andrea Raponi, Michael R. Combi, Priscilla Cerroni, Yves Langevin, L. Moroz, Pierre Drossart, Ulrich Schade, G. P. Tozzi, Wing-Huen Ip, Luigi Colangeli, Fredric W. Taylor, Angioletta Coradini, J. Ph. Combe, Raffaella Noschese, Enrico Flamini, Giancarlo Bellucci, Ernesto Palomba, Sonia Fornasier, F. Merlin, Lydie Bonal, Andrea Longobardo, G. Peter, M. Cartacci, Alessandro Frigeri, Giuseppe Piccioni, Bernard Schmitt, Uwe Fink, Ralf Jaumann, Mauro Ciarniello, D. Despan, M. A. Barucci, Giovanna Rinaldi, Pierre Beck, M. C. De Sanctis, S. Giuppi, S. Jacquinod, Uri Carsenty, D. Bockelee-Morvan, Eric Quirico, Stefano Mottola, F. Henry, N. Biver, Jean-Pierre Bibring, Patrick G. J. Irwin, T. Encrenaz, Katrin Stephan, Andrea Cicchetti, Johannes Benkhoff, C. Leyrat, Gianrico Filacchione, D. Tiphene, J. M. Reess, T. B. McCord, Sergio Fonti, Costanzo Federico, Eleonora Ammannito, M. I. Blecka, Pasquale Palumbo, Armando Blanco, M. Gudipati, Fabrizio Capaccioni, Vito Mennella, Federico Tosi, E. Kuehrt, F., Capaccioni, A., Coradini, G., Filacchione, S., Erard, G., Arnold, P., Drossart, M. C., De Sancti, D., Bockelee Morvan, M. T., Capria, F., Tosi, C., Leyrat, B., Schmitt, E., Quirico, P., Cerroni, V., Mennella, A., Raponi, M., Ciarniello, T., Mccord, L., Moroz, E., Palomba, E., Ammannito, M. A., Barucci, G., Bellucci, J., Benkhoff, J. P., Bibring, Blanco, Armando, M., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, M., Combi, J., Crovisier, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, W. H., Ip, P., Irwin, R., Jaumann, E., Kuehrt, Y., Langevin, G., Magni, S., Mottola, Orofino, Vincenzo, P., Palumbo, G., Piccioni, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, P., Beck, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, S., Fornasier, A., Frigeri, D., Grassi, M., Gudipati, A., Longobardo, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, K., Stephan, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, R., Noschese, G., Peter, R., Politi, J. M., Ree, A., Semery, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Polska Akademia Nauk (PAN), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, German Aerospace Center (DLR), Department of Physics [Imperial College London], Imperial College London, Instituto de Estudos Avançados (IEAV), Institut, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Dipartimento di Fisica, Università degli studi di Lecce, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], DLR Institute of Planetary Research, Department of Physics [Lecce], Università del Salento [Lecce], INAF - Osservatorio Astrofisico di Arcetri (OAA), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Alenia Aerospazio, JDS Uniphase/Cronos, USA, JDS Uniphase/Cronos, CNR-IASF, IASI (IASI), Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Polska Akademia Nauk = Polish Academy of Sciences (PAN), NASA-California Institute of Technology (CALTECH), University of Oxford, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, DEU, TWN, NLD, and POL

Subjects
67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Opacity, Rosetta mission, VIRTIS, comets, Infrared, Comet, Imaging spectrometer, Astrophysics, 01 natural sciences, Astrobiology, comet, 0103 physical sciences, Spectral slope, Thermal, Rosetta, Rosetta mission, comets, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Chemistry, Albedo, VIRTIS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], organic-rich
Abstract

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ −1 ), and the broad absorption feature in the 2.9-to-3.6–micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Published
2015
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18. The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko

Author

DE SANCTIS, MARIA CRISTINA, CAPACCIONI, FABRIZIO, CIARNIELLO, Mauro, FILACCHIONE, GIANRICO, FORMISANO, Michelangelo, Mottola, S., RAPONI, Andrea, TOSI, Federico, Bockelée-Morvan, D., Erard, S., Leyrat, C., Schmitt, B., Ammannito, E., Arnold, G., Barucci, M. A., Combi, M., Capria, M. T., Cerroni, P., Ip, W. -H., Kuehrt, E., McCord, T. B., PALOMBA, Ernesto, Beck, P., Quirico, E., VIRTIS Team, PICCIONI, GIUSEPPE, BELLUCCI, Giancarlo, Fulchignoni, M., Jaumann, R., Stephan, K., Longobardo, A., MENNELLA, Vito, MIGLIORINI, Alessandra, Benkhoff, J., Bibring, J. P., Blanco, A., Blecka, M., Carlson, R., Carsenty, U., Colangeli, L., Combes, M., Crovisier, J., Drossart, P., Encrenaz, T., Federico, C., Fink, U., Fonti, S., Irwin, P., Langevin, Y., Magni, G., Moroz, L., Orofino, V., Schade, U., Taylor, F., Tiphene, D., Tozzi, G. P., Biver, N., Bonal, L., Combe, J. -Ph., Despan, D., Flamini, E., Fornasier, S., FRIGERI, ALESSANDRO, GRASSI, Davide, Gudipati, M. S., Mancarella, F., Markus, K., Merlin, F., OROSEI, ROBERTO, RINALDI, GIOVANNA, CARTACCI, MARCO, Cicchetti, A., GIUPPI, Stefano, Hello, Y., Henry, F., Jacquinod, S., Rees, J. M., NOSCHESE, RAFFAELLA, POLITI, ROMOLO, Peter, G., M. C., De Sancti, F., Capaccioni, M., Ciarniello, G., Filacchione, M., Formisano, S., Mottola, A., Raponi, F., Tosi, D., Bockele´e Morvan, S., Erard, C., Leyrat, B., Schmitt, E., Ammannito, G., Arnold, M. A., Barucci, M., Combi, M. T., Capria, P., Cerroni, W. H., Ip, E., Kuehrt, T. B., Mccord, E., Palomba, P., Beck, E., Quirico, G., Piccioni, G., Bellucci, M., Fulchignoni, R., Jaumann, K., Stephan, A., Longobardo, V., Mennella, A., Migliorini, J., Benkhoff, J. P., Bibring, Blanco, Armando, M., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, J., Crovisier, P., Drossart, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, P., Irwin, Y., Langevin, G., Magni, L., Moroz, Orofino, Vincenzo, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, S., Fornasier, A., Frigeri, D., Grassi, M. S., Gudipati, Mancarella, Francesca, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, J. M., Ree, R., Noschese, R., Politi, G., Peter, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Laboratoire de Sciences de la Terre, ITA, USA, GBR, FRA, DEU, TWN, NLD, POL, and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
67P/Churyumov-Gerasimenko, Time Factors, Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Comet, 01 natural sciences, water ice, Astrobiology, comet, Diurnal cycle, 0103 physical sciences, Sunrise, Water cycle, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Meteoroid, Ice, Diurnal temperature variation, Temperature, food and beverages, Meteoroids, Environmental science, Volatilization, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Surface water, cycle of water ice, Water vapor
Abstract

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

Published
2015
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