118 results on '"Carson, J. C"'
Search Results
2. Multiwavelength study of Chandra X-ray sources in the Antennae.
- Author
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Clark, D. M., Eikenberry, S. S., Brandl, B. R., Wilson, J. C., Carson, J. C., Henderson, C. P., Hayward, T. L., Barry, D. J., Ptak, A. F., and Colbert, E. J. M.
- Subjects
WAVELENGTHS ,INFRARED imaging ,CAMERAS ,ASTRONOMICAL photometry ,STARBURSTS ,STAR clusters ,X-rays - Abstract
ABSTRACT We use Wide-field InfraRed Camera (WIRC) infrared (IR) images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources to search for counterpart candidates. Using our proven frame-tie technique, we find 38 X-ray sources with IR counterparts, almost doubling the number of IR counterparts to X-ray sources that we first identified. In our photometric analysis, we consider the 35 IR counterparts that are confirmed star clusters. We show that the clusters with X-ray sources tend to be brighter, K
s ≈ 16 mag, with ( J− Ks ) = 1.1 mag. We then use archival Hubble Space Telescope ( HST) images of the Antennae to search for optical counterparts to the X-ray point sources. We employ our previous IR-to-X-ray frame-tie as an intermediary to establish a precise optical-to-X-ray frame-tie with <0.6 arcsec rms positional uncertainty. Due to the high optical source density near the X-ray sources, we determine that we cannot reliably identify counterparts. Comparing the HST positions to the 35 identified IR star cluster counterparts, we find optical matches for 27 of these sources. Using Bruzual-Charlot spectral evolutionary models, we find that most clusters associated with an X-ray source are massive, and young, ∼ 106 yr. [ABSTRACT FROM AUTHOR]- Published
- 2011
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3. The influence of differences between venture studios on differences in venture outcomes.
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Patel, Pankaj C. and Chan, C. S. Richard
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ANALYSIS of variance ,TRANSACTION cost theory of the firm ,ASSEMBLY line methods ,TRANSACTION costs ,RESOURCE-based theory of the firm - Abstract
Venture studios present an intriguing proposition for entrepreneurship theory – a shift from venturing as an entrepreneur-driven activity to venturing as an "assembly line" serialization in an organization. We ask the question whether between-venture studio differences explain the differences in outcomes among the ventures they create. We hypothesize that venture studios explain meaningful variance in explaining venture outcomes. Our empirical study is based on a sample of 350 venture studios from 34 countries, 257 industries, and startup-founding years, ranging from 1994 to 2022. We focus on the sales, employees, and whether the venture was acquired or went IPO. Using variance decomposition analysis, we find that differences in venture studios explain most of the variance in differences in venture outcomes (~30%), with low teens to single-digit variances explained by studio-founding year, venture founding year, country, and industry effects. To our knowledge, this is the largest and most comprehensive empirical study of venture studios to date, and variance decomposition analysis presents an important first step to assessing whether the unique resources and the transaction cost benefits afforded by venture studios explain differences in performance between ventures. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Insights into embryonic chromosomal instability: mechanisms of DNA elimination during mammalian preimplantation development.
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Budrewicz, Jacqueline and Chavez, Shawn L.
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NUCLEAR membranes ,EMBRYO implantation ,MAMMALIAN embryos ,NUCLEAR DNA ,SOMATIC cells ,MEIOSIS - Abstract
Mammalian preimplantation embryos often contend with aneuploidy that arose either by the inheritance of meiotic errors from the gametes, or from mitotic mis-segregation events that occurred following fertilization. Regardless of the origin, mis-segregated chromosomes become encapsulated in micronuclei (MN) that are spatially isolated from the main nucleus. Much of our knowledge of MN formation comes from dividing somatic cells during tumorigenesis, but the error-prone cleavage-stage of early embryogenesis is fundamentally different. One unique aspect is that cellular fragmentation (CF), whereby small subcellular bodies pinch off embryonic blastomeres, is frequently observed. CF has been detected in both in vitro and in vivo-derived embryos and likely represents a response to chromosome mis-segregation since it only appears after MN formation. There are multiple fates for MN, including sequestration into CFs, but the molecular mechanism(s) by which this occurs remains unclear. Due to nuclear envelope rupture, the chromosomal material contained within MN and CFs becomes susceptible to double stranded-DNA breaks. Despite this damage, embryos may still progress to the blastocyst stage and exclude chromosome-containing CFs, as well as non-dividing aneuploid blastomeres, from participating in further development. Whether these are attempts to rectify MN formation or eliminate embryos with poor implantation potential is unknown and this review will discuss the potential implications of DNA removal by CF/blastomere exclusion. We will also extrapolate what is known about the intracellular pathways mediating MN formation and rupture in somatic cells to preimplantation embryogenesis and how nuclear budding and DNA release into the cytoplasm may impact overall development. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. ZnSSe Decorated Reduced Graphene Oxide for Enhanced Photoelectric Properties.
- Author
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Deng, Yifan, Lei, Yun, Tang, Zehui, Chen, Jiong, Luo, Linhui, Wang, Yongqin, Li, Can, Du, Beibei, Wang, Shiquan, and Sun, Zhengguang
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CARRIER density ,ELECTRON-hole recombination ,ZINC sulfide ,CHARGE transfer ,ZINC selenide ,GRAPHENE ,GRAPHENE oxide - Abstract
ZSSG (ZnSSe/rGO) composites are prepared by a hydrothermal method. The structure, morphology and material properties are investigated by various tests. Compared to ZnSe, the diffraction peaks of ZnSSe are moved to a larger angle and located between cubic phase ZnSe and cubic phase ZnS. The photocurrent density of ZSSG20 with 20 wt.% graphene is 2.17×10−5 A cm−2, which is 8.9 times higher than that of pure ZnSSe. ZSSG20 has the minimum charge transfer resistance and highest carrier density. The decreased fluorescence intensity in PL spectra indicates that graphene can effectively prevent the recombination of electron‐hole pairs. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Magnetic activity variability of nearby bright Sun-like stars by 4 yr intensive Hα line monitoring.
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Lee, Sanghee, Notsu, Yuta, and Sato, Bun'ei
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STELLAR chromospheres ,PLANETARY systems ,STELLAR activity - Abstract
We report intensive monitoring of the activity variability in the Hα line for 10 Sun-like stars using the 1.88 m reflector at Okayama Branch Office, Subaru Telescope, during the last four years (2019–2022). Our aim was to investigate features of the stellar magnetic activity behavior. We correlated the Hα line variability of each star with the stellar activity levels derived from the Ca ii H&K line, suggesting its efficiency as a magnetic activity indicator. In analyzing the Hα line variation, we observed that some stars exhibited linear or quadratic trends during the observation period. Among several G- and K-type stars expected to have co-existing activity cycles, we confirmed the 2.9 yr short cycle of ϵ Eri (K2V) from the Hα observations. Additionally, we established upper limits on the Hα variability of β Com (G0V) and κ
1 Cet (G5V) concerning their expected shorter cycles. We also detected the possibility of short-term activity cycles in two F-type stars, β Vir (F9V; ∼530 d) and α CMi (F5IV-V; ∼130 d). The cycle in α CMi was observed in only one season of our 4 yr observations, suggesting the temporal absence of the cycle period. However, for stars with planets, we did not observe significant magnetic activity variability likely associated with the planetary orbital period. It is speculated that the impact of Hα variability on radial velocity (RV) measurements may vary with spectral type. [ABSTRACT FROM AUTHOR]- Published
- 2024
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7. Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions.
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Punchihewa, Buwanila T., Minda, Vidit, Gutheil, William G., and Rafiee, Mohammad
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ELECTRIC batteries ,CHEMICAL reactions ,PIPETTES ,ELECTROCHEMISTRY ,ELECTROSYNTHESIS ,ELECTROLYSIS - Abstract
Electrochemistry represents unique approaches for the promotion and mechanistic study of chemical reactions and has garnered increasing attention in different areas of chemistry. This expansion necessitates the enhancement of the traditional electrochemical cells that are intrinsically constrained by mass transport limitations. Herein, we present an approach for designing an electrochemical cell by limiting the reaction chamber to a thin layer of solution, comparable to the thickness of the diffusion layer. This thin layer electrode (TLE) provides a modular platform to bypass the constraints of traditional electrolysis cells and perform electrolysis reactions in the timescale of electroanalytical techniques. The utility of the TLE for electrosynthetic applications benchmarked using NHPI‐mediated electrochemical C−H functionalization. The application of microscale electrolysis for the study of drug metabolites was showcased by elucidating the oxidation pathways of the paracetamol drug. Moreover, hosting a microelectrode in the TLE, was shown to enable real‐time probing of the profiles of redox‐active components of these rapid electrosynthesis reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. Do Firms Earn Rents from the Intangible Assets of Their Owners? Institution-Based Insights from the Energy Sector.
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Aliyev, Murod and Kafouros, Mario
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BUSINESS ethics ,RENEWABLE energy transition (Government policy) ,RENT (Economic theory) ,BUSINESS planning ,ECONOMIC statistics ,COMPUTER software industry - Abstract
The article delves into how firms in the energy sector in Europe can earn economic rents from intangible assets, specifically firm-owned intangible assets (FIAs) and owner organizations' intangible assets (OIAs). It highlights the influence of institutional quality on rent creation, showing that FIAs benefit from higher quality institutions while OIAs are negatively affected. The study also emphasizes the advantage of OIAs in multiple-ownership settings, particularly in countries with better institutional quality. Overall, the research contributes to understanding how different types of intangible assets generate rents for firms and how institutional context shapes this process, with a focus on international business and corporate governance in emerging economies like China. [Extracted from the article]
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- 2023
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9. LABS: Laboratory Automation and Batch Scheduling – A Modular Open Source Python Program for the Control of Automated Electrochemical Synthesis with a Web Interface.
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Hielscher, Maximilian M., Dörr, Maurice, Schneider, Johannes, and Waldvogel, Siegfried R.
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AUTOMATION software ,PYTHON programming language ,OXIDATIVE coupling ,AUTOMATION ,ELECTROLYSIS ,SCHEDULING - Abstract
With LABS, an open source Python‐based lab software is established that enables users to orchestrate automated synthesis setups. The software consists of a user‐friendly interface for data input and system monitoring. A flexible backend architecture enables the integration of multiple lab devices. The software allows users to easily modify experimental parameters or routines and switch between different lab devices. Compared to previously published projects, we aim to provide a more widely applicable and easily customizable automation software for any experimental setup. The usefulness of this tool was demonstrated in the oxidative coupling of 2,4‐dimethyl‐phenol to the corresponding 2,2'‐biphenol. In this context, the suitable electrolysis parameters for flow electrolysis were optimized by way of design of experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. Anthropometrics and body composition predict performance during a simulated direct-fire engagement.
- Author
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Stein, Jesse A., Hepler, Timothy C., DeBlauw, Justin A., Beattie, Cassandra M., Beshirs, Chaddrick D., Holte, Kendra M., Kurtz, Brady K., Hatch-McChesney, Adrienne, Heinrich, Katie M., and Farina, Emily K.
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MILITARY education ,BODY composition ,EXPERIMENTAL design ,ANTHROPOMETRY ,SIMULATION methods in education ,PSYCHOLOGY of movement ,COGNITION ,ABILITY ,BODY movement ,VISUAL acuity ,RESEARCH funding ,BODY mass index ,FIRES ,MILITARY personnel - Abstract
This study determined anthropometric and body composition predictors of performance during a simulated direct-fire engagement. Healthy subjects (N = 33, age = 25.7 ± 7.0 yr) underwent anthropometric and body composition assessments before completing a simulated direct-fire engagement – consisting of marksmanship with cognitive workload assessment and a fire-and-move drill (16 × 6-m sprints) while wearing combat load. Susceptibility to enemy fire was modelled on sprint duration. Partial correlations and multiple linear regressions established the relationships between predictors and performance outcomes, controlling for age and sex. Significance was p ≤ 0.05. Higher percent body fat, fat mass, fight load index predicted greater susceptibility to enemy fire (r = 0.40 to 0.42) and lower cognitive performance (r= -0.45 to −0.49). Higher BMI also predicted lower cognitive performance (r= -0.49). Shorter stature/hand length predicted higher marksmanship accuracy (r= -0.40), while higher fat-free mass/fat-free mass index predicted slower reaction times (r = 0.36–0.41). These data suggest anthropometric and body composition measures modulate combat effectiveness and reinforce body composition standards in military organisations. Practitioner summary: This study identified field-expedient anthropometric and body composition predictors of a simulated direct-fire engagement that evaluated survivability (i.e. susceptibility to enemy fire) and lethality (i.e. marksmanship, cognitive performance) outcomes. Our findings suggest that anthropometric and body composition measures may play a role in soldier survivability and lethality during simulated direct-fire engagements. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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11. Sustainability and Semantic Diversity: A View from the Malayan Rainforest.
- Author
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Burenhult, Niclas
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RAIN forests ,SUSTAINABILITY ,COMMUNITIES ,UNIVERSAL language ,SUSTAINABLE development - Abstract
Sustainable development goals assume that basic notions, such as health, life, and water, can be universally and easily expressed and understood across diverse communities and stakeholders. Yet, there is growing evidence pointing to considerable semantic diversity in how humans represent the world in language. In this paper, I discuss such semantic diversity in the context of key notions of sustainability. Focusing on an environmental term of broad relevance to sustainability goals, forest, I explore how this notion compares with assumed equivalent notions in a non‐Western lesser‐known speech community. Specifically, I analyze representations of treed environments in the language of the Jahai, a forager community inhabiting the rainforests of the Malay Peninsula. The results show that an understanding of local indigenous systems of representation can be crucial to the communication and implementation of sustainability goals. Sustainable development goals assume that environmental notions can be universally expressed and understood across languages. In this paper I discuss the notion of forest in the context of an indigenous Jahai term, showing that there are significant challenges to translation and communication of such notions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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12. The Cornell High-Order Adaptive Optics Survey for Brown Dwarfs in Stellar Systems. I. Observations, Data Reduction, and Detection Analyses.
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Carson, J. C., Eikenberry, S. S., Brandl, B. R., Wilson, J. C., and Hayward, T. L.
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- 2005
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13. Observations of planet forming disks in multiple stellar systems.
- Author
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Zurlo, Alice, Gratton, Raffaele, Pérez, Sebastián, and Cieza, Lucas
- Abstract
The demographic of circumstellar disks, the birthplaces of planets, is diverse and rich in disks featuring rings, gaps, spirals, filaments, and arcs. Many studies revealing these disk structures have focused on objects around single stars and disks in isolation. The scenario is more complex if binarity or multiplicity is involved; most stars are part of multiple systems in crowded star-forming regions. How does the presence of one or more stellar companions affect the shape and size of the circumstellar disks? Here we review the landscape of results from optical, infrared, and (sub-) millimeter observations of the effects of multiplicity on protoplanetary disks, emphasizing the demographic studies of nearby molecular clouds and the high-resolution studies of multiple disk systems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. How Employees' Roles and Communication Responsibility Play a Role in an Ideation Process on Internal Social Media.
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Andersen, Mona Agerholm and Gode, Helle Eskesen
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SOCIAL media ,SOCIAL processes ,ROLE playing ,JOB security ,IDENTITY (Psychology) ,SHIFT systems ,DISCOURSE analysis ,INTERNAL auditing ,ABSORPTIVE capacity (Economics) - Abstract
This article contributes to the emerging research on employees' communication roles and responsibility. The article explores how and why employees act as responsible communicators while shifting between different roles in an ideation process on internal social media. The empirical material consists of online observations of employee ideation on internal social media and 14 interviews with employees in a Danish knowledge-intensive organization. Drawing on identity work and discourse analysis, this article analyzes the different roles that employees enact, shift and position themselves in when generating ideas on internal social media. The analysis identified eight different communication roles: Diplomat, Expert, Forecaster, Veteran, Facilitator, Investigator, Skeptic, and Apprentice. The role framework provides new knowledge on the diversity and characteristics of employees' roles on a micro-level and how they complement each other in driving the ideation process forward. This framework may provide managers with an analytical lens to identify potential challenges related to role enactment at different stages of the process. Awareness of the different roles and their significance for the process may also encourage employees to overcome barriers such as insecurity and fear of critical reactions from their colleagues when they generate ideas online in a context of volatility, uncertainty, complexity and ambiguity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Stable accretion and episodic outflows in the young transition disk system GM Aurigae: A semester-long optical and near-infrared spectrophotometric monitoring campaign.
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Bouvier, J., Sousa, A., Pouilly, K., Almenara, J. M., Donati, J.-F., Alencar, S. H. P., Frasca, A., Grankin, K., Carmona, A., Pantolmos, G., Zaire, B., Bonfils, X., Bayo, A., Rebull, L. M., Alonso-Santiago, J., Gameiro, J. F., Cook, N. J., and Artigau, E.
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ACCRETION (Astrophysics) ,NEAR infrared spectroscopy ,NEAR infrared radiation ,CIRCUMSTELLAR matter ,STARSPOTS ,STELLAR rotation ,BIPOLAR outflows (Astrophysics) - Abstract
Context. Young stellar systems actively accrete from their circumstellar disk and simultaneously launch outflows. The physical link between accretion and ejection processes remains to be fully understood. Aims. We investigate the structure and dynamics of magnetospheric accretion and associated outflows on a scale smaller than 0.1 au around the young transitional disk system GM Aur. Methods. We devised a coordinated observing campaign to monitor the variability of the system on timescales ranging from days to months, including partly simultaneous high-resolution optical and near-infrared spectroscopy, multiwavelength photometry, and lowresolution near-infrared spectroscopy, over a total duration of six months, covering 30 rotational cycles. We analyzed the photometric and line profile variability to characterize the accretion and ejection processes. Results. The optical and near-infrared light curves indicate that the luminosity of the system is modulated by surface spots at the stellar rotation period of 6.04 ± 0.15 days. Part of the Balmer, Paschen, and Brackett hydrogen line profiles as well as the HeI 5876Å and HeI 10830Å line profiles are modulated on the same period. The Pa line flux correlates with the photometric excess in the u0 band, which suggests that most of the line emission originates from the accretion process. High-velocity redshifted absorptions reaching below the continuum periodically appear in the near-infrared line profiles at the rotational phase in which the veiling and line fluxes are the largest. These are signatures of a stable accretion funnel flow and associated accretion shock at the stellar surface. This large-scale magnetospheric accretion structure appears fairly stable over at least 15 and possibly up to 30 rotational periods. In contrast, outflow signatures randomly appear as blueshifted absorption components in the Balmer and HeI 10830Å line profiles. They are not rotationally modulated and disappear on a timescale of a few days. The coexistence of a stable, large-scale accretion pattern and episodic outflows supports magnetospheric ejections as the main process occurring at the star-disk interface. Conclusions. Long-term monitoring of the variability of the GM Aur transitional disk system provides clues to the accretion and ejection structure and dynamics close to the star. Stable magnetospheric accretion and episodic outflows appear to be physically linked on a scale of a few stellar radii in this system. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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16. A machine learning approach for correcting radial velocities using physical observables.
- Author
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Perger, M., Anglada-Escudé, G., Baroch, D., Lafarga, M., Ribas, I., Morales, J. C., Herrero, E., Amado, P. J., Barnes, J. R., Caballero, J. A., Jeffers, S. V., Quirrenbach, A., and Reiners, A.
- Subjects
MACHINE learning ,NOISE control ,VELOCITY ,STELLAR chromospheres - Abstract
Context. Precision radial velocity (RV) measurements continue to be a key tool for detecting and characterising extrasolar planets. While instrumental precision keeps improving, stellar activity remains a barrier to obtaining reliable measurements below 1-2ms-1 accuracy. Aims. Using simulations and real data, we investigate the capabilities of a deep neural network approach to producing activity-free Doppler measurements of stars. Methods. As case studies we used observations of two known stars, Eridani and AUMicroscopii, both of which have clear signals of activity-induced Doppler variability. Synthetic observations using the starsim code were generated for the observables (inputs) and the resulting Doppler signal (labels), and then they were used to train a deep neural network algorithm to predict Doppler corrections. We identified a relatively simple architecture, consisting of convolutional layers followed by fully connected layers, that is adequate for the task. The indices investigated are mean line-profile parameters (width, bisector, and contrast) and multi-band photometry. Results. We demonstrate that the RV-independent approach can drastically reduce spurious Doppler variability from known physical effects, such as spots, rotation, and convective blueshift. We identify the combinations of activity indices with the most predictive power. When applied to real observations, we observe a good match of the correction with the observed variability, but we also find that the noise reduction is not as good as in the simulations, probably due to a lack of detail in the simulated physics. Conclusions. We demonstrate that a model-driven machine learning approach is sufficient to clean Doppler signals from activityinduced variability for well-known physical effects. There are dozens of known activity-related observables whose inversion power remains unexplored, indicating that the use of additional indicators, more complete models, and more observations with optimised sampling strategies can lead to significant improvements in our detrending capabilities for new and existing datasets. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. Stirring‐Free Scalable Electrosynthesis Enabled by Alternating Current.
- Author
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Bortnikov, Evgeniy O., Smith, Barbara S., Volochnyuk, Dmitriy M., and Semenov, Sergey N.
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ALTERNATING currents ,ELECTROSYNTHESIS ,ELECTROLYSIS ,SURFACE area ,SUSTAINABLE chemistry ,ELECTRODES - Abstract
Alternating current (AC) electrolysis is receiving increased interest as a versatile tool for mild and selective electrochemical transformations. This work demonstrates that AC can enable the concept of a stirring‐free electrochemical reactor where the periodic switch of electrode polarity, inherent to AC, provides uniform electrolysis across the whole volume of the reactor. Such design implies a straightforward approach for scaling up electrosynthesis. This was demonstrated on the range of electrochemical transformations performed in three different RVC‐packed reactors on up to a 50‐mmol scale. Redox‐neutral, oxidative, and reductive processes were successfully implemented using the suggested design and the applicable frequency ranges were further investigated for different types of reactions. The advantages of the AC‐enabled design – such as the absence of stirring and a maximized surface area of the electrodes – provide the possibility for its universal application both for small‐scale screening experimentation and large‐scale preparative electrosynthesis without significant optimization needed in between. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. Imaging of exocomets with infrared interferometry.
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Janson, Markus, Patel, Jayshil, Ringqvist, Simon C., Lu, Cicero, Rebollido, Isabel, Lichtenberg, Tim, Brandeker, Alexis, Angerhausen, Daniel, and Noack, Lena
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COMETS ,INFRARED imaging ,HALE-Bopp comet ,SPECTRAL imaging ,HABITABLE planets ,INNER planets - Abstract
Active comets have been detected in several exoplanetary systems, although so far only indirectly, when the dust or gas in the extended coma has transited in front of the stellar disk. The large optical surface and relatively high temperature of an active cometary coma also makes it suitable to study with direct imaging, but the angular separation is generally too small to be reachable with present-day facilities. However, future imaging facilities with the ability to detect terrestrial planets in the habitable zones of nearby systems will also be sensitive to exocomets in such systems. Here we examine several aspects of exocomet imaging, particularly in the context of the Large Interferometer for Exoplanets (LIFE), which is a proposed space mission for infrared imaging and spectroscopy through nulling interferometry. We study what capabilities LIFE would have for acquiring imaging and spectroscopy of exocomets, based on simulations of the LIFE performance as well as statistical properties of exocomets that have recently been deduced from transit surveys. We find that for systems with extreme cometary activities such as β Pictoris, sufficiently bright comets may be so abundant that they overcrowd the LIFE inner field of view. More nearby and moderately active systems such as є Eridani or Fomalhaut may turn out to be optimal targets. If the exocomets have strong silicate emission features, such as in comet Hale-Bopp, it may become possible to study the mineralogy of individual exocometary bodies. We also discuss the possibility of exocomets as false positives for planets, with recent deep imaging of α Centauri as one hypothetical example. Such contaminants could be common, primarily among young debris disk stars, but should be rare among the main sequence population. We discuss strategies to mitigate the risk of any such false positives. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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19. Beyond torture: Knowledge and power at the nexus of social science and national security.
- Author
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Rohde, Joy
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TORTURE ,NATIONAL security ,MILITARY discipline ,WAR on Terrorism, 2001-2009 ,MONETARY incentives ,INTELLIGENCE service - Abstract
In the wake of revelations about the American Psychological Association's complicity in the military's enhanced interrogation program, some psychologists have called upon the association to sever its ties to national security agencies. But psychology's relationship to the military is no short-term fling born of the War on Terror. This article demonstrates that psychology's close relationship to national security agencies and interests has long been a visible and consequential feature of the discipline. Drawing on social scientific debates about the relationship between national security agencies and the social sciences in the late 1960s and early 1970s, this article also provides cautionary lessons for psychologists confronting the torture controversy. It concludes that an ethically robust response to this controversy requires that psychologists engage in a sustained reckoning with the powerful institutional, epistemological, and financial incentives that have bound the discipline to the military and intelligence communities since World War I. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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20. Additional evidence that Fomalhaut b might be a non-exoplanet.
- Author
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Vecchio, Alexa Del and Stone, Jonathon Rick
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NEUTRON stars ,DATA analysis ,ASTROBIOLOGY ,EXTRASOLAR planets - Abstract
Fomalhaut b is an extrasolar object that was imaged directly in 2008. Its status since has changed from exoplanet – including super-Earth and low-mass candidates – to neutron star to dust cloud, generating contention, controversy, and confusion. We contribute to the discussion by reporting additional evidence that, given a set containing celestial objects classified as exoplanets, Fomalhaut b might be a non-member. We conducted a principal component (PC) analysis on a data set containing 425 extrasolar objects and 7 variables and found a single isolated point in PC space representing Fomalhaut b. Whatever its existential status, Fomalhaut b is characterized by properties very different from those characterizing exoplanets. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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21. Creation of a UX index to design human tasks and workstations.
- Author
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Grandi, Fabio, Peruzzini, Margherita, Cavallaro, Sara, Prati, Elisa, and Pellicciari, Marcello
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MANUFACTURING workstations ,USER experience ,ERGONOMICS ,TASKS - Abstract
Successful interaction with complex processes, like those in the modern factory, is based on the system's ability to satisfy the user needs during human tasks, mainly related to performances, physical comfort, usability, accessibility, visibility, and mental workload. However, the 'real' user perception is hidden and usually difficult to detect. User eXperience (UX) is a useful concept related to subjective perceptions and responses that result from the interaction with a product, system or process, including users' emotions, beliefs, preferences, perceptions, physical and psychological responses, behaviors and accomplishments that occur before, during and after use. The paper proposes the creation of a User eXperience Index (UXI) to assess the quality of human-system interaction during job tasks and, consequently, evaluate both process and workstation. The proposed approach has been applied to improve the design of assembly human tasks, using a virtual simulated case study focusing on tractor assembly. Tests with users, with different levels of expertise, allowed us to validate the proposed approach and to optimize the assembly task sequence. Results showed how the proposed UXI can validly objectify the workers' experience and can be validly used to improve the design of human tasks. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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22. Lower Extremity Impact and Injury Responses of Male and Female PMHS to High-Rate Vertical Loading.
- Author
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Cristino, D., Pietsch, H., Kemper, A., Bolte, J., Danelson, K., and Hardy, W.
- Abstract
Whole-body PMHS (Post Mortem Human Surrogate) testing was conducted on the Accelerative Loading Fixture (ALF), which is designed to generate floor and seat loading conditions at the level, rate, location, direction, and extent seen in UBB (Underbody Blast). The overarching goal of this research effort was to examine potential differences in the lower extremity response of females and males under UBB conditions. The ALF consists of an occupant platform that is driven upward by the detonation of an explosive charge. The floor plate undergoes plastic deformation. The occupant platform supports two rigid seats for surrogates. Twenty un-embalmed PMHS were tested, including 50th-percentile males, 75th-percentile females, and 5th-percentile females. Two test series were conducted. Series A had a target floor speed of 8 m/s (2-ms time-to-peak) with a target seat speed of 5 m/s (4-ms time-to-peak). Series B had a target floor speed of 20 m/s (2-ms time-to-peak) with a target seat speed of 4 m/s (7-ms time-to-peak). Major damage occurred to the femur, tibia, fibula, talus, and calcaneus. Lower extremity damage type, incidence, and extent varied between the two sexes. Fifty-percent probability of calcaneus fracture for less than 3-ms time-to-peak is associated with a 781-g peak tibia vertical acceleration for 50th-percentile males, 650-g for 75th-percentile females, and 396-g for 5th-percentile females. Fifty-percent probability of calcaneus fracture, regardless of time-to-peak, is associated with a 368-g peak femur vertical acceleration for 50th-percentile males, 332-g for 75th-percentile females, and 218-g for 5th-percentile females. These results show differences in kinematics and damage outcome between female and male PMHS in UBB conditions. These findings will inform future decisions regarding the requirements for test capabilities that incorporate the female Warfighter. Ultimately, advancements can be made in injury assessment tools such as improved physical surrogates, injury assessment and prediction criteria, modeling and simulation capabilities, test methods, and the optimization of military ground vehicles, personal protective equipment, and injury countermeasures. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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23. Sex differences in changes of protein synthesis with rapamycin treatment are minimized when metformin is added to rapamycin.
- Author
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Wolff, Christopher A., Lawrence, Marcus M., Porter, Hunter, Zhang, Qian, Reid, Justin J., Laurin, Jaime L., Musci, Robert V., Linden, Melissa A., Peelor III, Frederick F., Wren, Jonathan D., Creery, Joseph S., Cutler, Kyle J., Carson, Richard H., Price, John C., Hamilton, Karyn L., and Miller, Benjamin F.
- Subjects
PROTEIN synthesis ,DEUTERIUM oxide ,RAPAMYCIN ,METFORMIN ,SKELETAL muscle ,WESTERN diet - Abstract
Loss of protein homeostasis is a hallmark of the aging process. We and others have previously shown that maintenance of proteostasis is a shared characteristic of slowed-aging models. Rapamycin (Rap) exerts sex-specific effects on murine lifespan, but the combination of Rap with the anti-hyperglycemic drug metformin (Rap + Met) equally increases male and female mouse median lifespan. In the current investigation, we compare the effects of short-term (8 weeks) Rap and Rap + Met treatments on bulk and individual protein synthesis in two key metabolic organs (the liver and skeletal muscle) of young genetically heterogeneous mice using deuterium oxide. We report for the first time distinct effects of Rap and Rap + Met treatments on bulk and individual protein synthesis in young mice. Although there were decreases in protein synthesis as assessed by bulk measurements, individual protein synthesis analyses demonstrate there were nearly as many proteins that increased synthesis as decreased synthesis rates. While we observed the established sex- and tissue-specific effects of Rap on protein synthesis, adding Met yielded more uniform effects between tissue and sex. These data offer mechanistic insight as to how Rap + Met may extend lifespan in both sexes while Rap does not. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. The HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo.
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Defrčre, D., Hinz, P. M., Kennedy, G. M., Stone, J., Rigley, J., Ertel, S., Gaspar, A., Bailey, V. P., Hoffmann, W. F., Mennesson, B., Millan-Gabet, R., Danchi, W. C., Absil, O., Arbo, P., Beichman, C, Bonavita, M, Brusa, G., Bryden, G., Downey, E. C., and Esposito, S.
- Published
- 2021
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25. A Decade of Radial-velocity Monitoring of Vega and New Limits on the Presence of Planets.
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Hurt, Spencer A., Quinn, Samuel N., Latham, David W., Vanderburg, Andrew, Esquerdo, Gilbert A., Calkins, Michael L., Berlind, Perry, Angus, Ruth, Latham, Christian A., and Zhou, George
- Published
- 2021
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26. The Effect of Muscle Activation on Head Kinematics During Non-injurious Head Impacts in Human Subjects.
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Reynier, Kristen A., Alshareef, Ahmed, Sanchez, Erin J., Shedd, Daniel F., Walton, Samuel R., Erdman, Nicholas K., Newman, Benjamin T., Giudice, J. Sebastian, Higgins, Michael J., Funk, James R., Broshek, Donna K., Druzgal, Thomas J., Resch, Jacob E., and Panzer, Matthew B.
- Abstract
In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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27. Label-free adaptive optics imaging of human retinal macrophage distribution and dynamics.
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Hammer, Daniel X., Agrawal, Anant, Villanueva, Ricardo, Saeedi, Osamah, and Zhuolin Liu
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ADAPTIVE optics ,RETINAL imaging ,OPTICAL coherence tomography ,COHERENCE (Optics) ,CENTRAL nervous system - Abstract
Microglia are resident central nervous system macrophages and the first responders to neural injury. Until recently, microglia have been studied only in animal models with exogenous or transgenic labeling. While these studies provided a wealth of information on the delicate balance between neuroprotection and neurotoxicity within which these cells operate, extrapolation to human immune function has remained an open question. Here we examine key characteristics of retinal macrophage cells in live human eyes, both healthy and diseased, with the unique capabilities of our adaptive optics-optical coherence tomography approach and owing to their propitious location above the inner limiting membrane (ILM), allowing direct visualization of cells. Our findings indicate that human ILM macrophage cells may be distributed distinctly, age differently, and have different dynamic characteristics than microglia in other animals. For example, we observed a macular pattern that was sparse centrally and peaked peripherally in healthy human eyes. Moreover, human ILM macrophage density decreased with age (~2% of cells per year). Our results in glaucomatous eyes also indicate that ILM macrophage cells appear to play an early and regionally specific role of nerve fiber layer phagocytosis in areas of active disease. While we investigate ILM macrophage cells distinct from the larger sample of overall retinal microglia, the ability to visualize macrophage cells without fluorescent labeling in the live human eye represents an important advance for both ophthalmology and neuroscience, which may lead to novel disease biomarkers and new avenues of exploration in disease progression. [ABSTRACT FROM AUTHOR]
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- 2020
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28. Missed diagnoses: Clinically relevant lessons learned through medical mysteries solved by the Undiagnosed Diseases Network.
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Cope, Heidi, Spillmann, Rebecca, Rosenfeld, Jill A., Brokamp, Elly, Signer, Rebecca, Schoch, Kelly, Kelley, Emily G., Sullivan, Jennifer A., Macnamara, Ellen, Lincoln, Sharyn, Golden‐Grant, Katie, Orengo, James P., Clark, Gary, Burrage, Lindsay C., Posey, Jennifer E., Punetha, Jaya, Robertson, Amy, Cogan, Joy, Phillips, John A., and Martinez‐Agosto, Julian
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GENETIC testing ,GENETIC counseling ,PHARMACOGENOMICS ,NUCLEOTIDE sequencing ,VIGNETTES ,DIAGNOSIS - Abstract
Background: Resources within the Undiagnosed Diseases Network (UDN), such as genome sequencing (GS) and model organisms aid in diagnosis and identification of new disease genes, but are currently difficult to access by clinical providers. While these resources do contribute to diagnoses in many cases, they are not always necessary to reach diagnostic resolution. The UDN experience has been that participants can also receive diagnoses through the thoughtful and customized application of approaches and resources that are readily available in clinical settings. Methods: The UDN Genetic Counseling and Testing Working Group collected case vignettes that illustrated how clinically available methods resulted in diagnoses. The case vignettes were classified into three themes; phenotypic considerations, selection of genetic testing, and evaluating exome/GS variants and data. Results: We present 12 participants that illustrate how clinical practices such as phenotype‐driven genomic investigations, consideration of variable expressivity, selecting the relevant tissue of interest for testing, utilizing updated testing platforms, and recognition of alternate transcript nomenclature resulted in diagnoses. Conclusion: These examples demonstrate that when a diagnosis is elusive, an iterative patient‐specific approach utilizing assessment options available to clinical providers may solve a portion of cases. However, this does require increased provider time commitment, a particular challenge in the current practice of genomics. [ABSTRACT FROM AUTHOR]
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- 2020
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29. Firm performance and regional economic freedom: the case of Russia.
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Bykova, Anna and Coates, Dennis
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ECONOMIC liberty ,ORGANIZATIONAL performance ,ECONOMIC expansion ,REGIONAL differences - Abstract
This study investigates whether the economic freedom of a region drives firm performance. Despite the large number of papers about the relationship between economic freedom and growth, there is still little evidence on the role of economic freedom in the performance of individual firms. We address this gap in the literature using hierarchical linear modeling, allowing us to investigate regional differences in company-level performance. The dataset consists of information about 1,096 companies combined with the Index of Economic Freedom for Russian regions during the period 2004–2014. [ABSTRACT FROM AUTHOR]
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- 2020
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30. Employee Ideation on Internal Social Media: Addressing Uncertainty through Dialogue Strategies.
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Gode, Helle Eskesen
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SOCIAL media ,UNCERTAINTY ,DIALOGUE ,EMPLOYEES - Abstract
This article examines employee ideation on internal social media, and how employees through dialogue strategies address uncertainty, a condition assumed inherent in ideation. The study explored online employee communication and interaction during 60 ideation sessions, including 2,420 suggested ideas, 6,558 comments, and 3,017 likes since the implementation in 2011 in a large, knowledge-intensive Danish organization. One ideation session counting 70 ideas, including 263 comments and 340 likes, was selected for an in-depth analysis of employee communication when generating ideas on internal social media. The study found that employees ideate mostly through three dialogue strategies: anticipating objections, asking directional questions, and opening up to other viewpoints. With these strategies, employees addressed uncertainty in mitigating interactions imagined to be face-threatening. Moreover, the present research suggests that uncertainty and dialogue strategies are considered resources for online employee ideation. Uncertainty may offer the opportunity for open, reflective, and stimulating dialogues, and the dialogue strategies may enhance online ideation. It is not until after an idea starts to develop through the multi-vocal dialogues that opportunities for innovation may emerge. In that sense, online employee communication about ideas is considered of strategic significance to one of the organization's goals of being an innovation leader. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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31. A half century of infrared astronomy--A personal recollection of the footprints in Japan.
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OKUDA, Haruyuki
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- 2019
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32. Beyond subjective judgments: Predicting evaluations of creative writing from computational linguistic features.
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Zedelius, Claire M., Mills, Caitlin, and Schooler, Jonathan W.
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CREATIVE writing ,READABILITY (Literary style) ,LINGUISTIC analysis ,SHORT story writing ,DIVERGENT thinking ,WORD frequency ,INTER-observer reliability - Abstract
The question of how to evaluate creativity in the context of creative writing has been a subject of ongoing discussion. A key question is whether something as elusive as creativity can be evaluated in a systematic way that goes beyond subjective judgments. To answer this question, we tested whether human evaluations of the creativity of short stories can be predicted by: (1) established measures of creativity and (2) computerized linguistic analyses of the stories. We conducted two studies, in which college students (with and without interest and experience in creative writing) wrote short stories based on a writing prompt. Independent raters (six in Study 1, five in Study 2) assessed the stories using an evaluation rubric specifically designed to assess aspects of creativity, on which they showed high interrater reliability. We provide evidence of convergent validity, in that the rubric evaluations correlated with established creativity measures, including measures of divergent thinking, associative fluency, and self-reported creative behavior and achievements. Linguistic properties of the short stories were analyzed with two computerized text analysis tools: Coh-Metrix, which analyzes aspects of text cohesion and readability, and Linguistic Inquiry and Word Count, which identifies meaningful psychological categories of the text content. Linguistic features predicted the human ratings of creativity to a significant degree. These results provide novel evidence that creative writing can be evaluated reliably and in a systematic way that captures objective features of the text. The results further establish our evaluation rubric as a useful tool to assess creative writing. [ABSTRACT FROM AUTHOR]
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- 2019
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33. Stellar and substellar companions of nearby stars from Gaia DR2: Binarity from proper motion anomaly.
- Author
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Kervella, Pierre, Arenou, Frédéric, Mignard, François, and Thévenin, Frédéric
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ASTROMETRY ,BROWN dwarf stars ,ORIGIN of planets ,STAR formation ,PLANETARY orbits ,MOTION - Abstract
Context. The census of stellar and substellar companions of nearby stars is largely incomplete, in particular toward the low-mass brown dwarf and long-period exoplanets. It is, however, fundamentally important in the understanding of the stellar and planetary formation and evolution mechanisms. Nearby stars are particularly favorable targets for high precision astrometry. Aims. We aim to characterize the presence of physical companions of stellar and substellar mass in orbit around nearby stars. Methods. Orbiting secondary bodies influence the proper motion of their parent star through their gravitational reflex motion. Using the HIPPARCOS and Gaia's second data release (GDR2) catalogs, we determined the long-term proper motion of the stars common to these two catalogs. We then searched for a proper motion anomaly (PMa) between the long-term proper motion vector and the GDR2 (or HIPPARCOS) measurements, indicative of the presence of a perturbing secondary object. We focussed our analysis on the 6741 nearby stars located within 50 pc, and we also present a catalog of the PMa for ≳99% of the HIPPARCOS catalog (≈117 000 stars). Results. 30% of the stars studied present a PMa greater than 3σ. The PMa allows us to detect orbiting companions, or set stringent limits on their presence. We present a few illustrations of the PMa analysis to interesting targets. We set upper limits of 0.1−0.3 M
J to potential planets orbiting Proxima between 1 and 10 au (Porb = 3 to 100 years). We confirm that Proxima is gravitationally bound to α Cen. We recover the masses of the known companions of ϵ Eri, ϵ Ind, Ross 614 and β Pic. We also detect the signature of a possible planet of a few Jovian masses orbiting τ Ceti. Conclusions. Based on only 22 months of data, the GDR2 has limitations. But its combination with the HIPPARCOS catalog results in very high accuracy PMa vectors, that already enable us to set valuable constraints on the binarity of nearby objects. The detection of tangential velocity anomalies at a median accuracy of σ(ΔvT ) = 1.0 m s−1 per parsec of distance is already possible with the GDR2. This type of analysis opens the possibility to identify long period orbital companions otherwise inaccessible. For long orbital periods, Gaia's complementarity to radial velocity and transit techniques (that are more sensitive to short orbital periods) already appears to be remarkably powerful. [ABSTRACT FROM AUTHOR]- Published
- 2019
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34. Feature reassembly in the acquisition of plural marking by Korean and Indonesian bilinguals.
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Lee, Eunji and Lardiere, Donna
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NUMBER (Grammar) ,LANGUAGE ability ,BILINGUALISM ,LANGUAGE & languages ,LINGUISTICS - Abstract
This bidirectional study investigated the L2 acquisition of plural marking in L2 Indonesian by native Korean speakers and in L2 Korean by native Indonesian speakers. Indonesian and Korean are classifier languages with partially overlapping restrictions on how pluralization interacts with quantification, allowing us to test the acquisition of new L2 features vs. the preemption of L1 features that are not in the L2. We also examined how the contextual complexity of new L2 features impacts development. Seventy learners at three L2 Korean proficiency levels and 40 native controls participated in Experiment 1; 61 learners at three L2 Indonesian proficiency levels and 39 native controls participated in Experiment 2. All participants completed three tasks – a Sentence Completion Task, a Grammaticality Judgment Task and a Multiple-Choice Task. Whereas learners were largely able to overcome the difficulty of preemption, they were less successful in acquiring new L2 feature contrasts in more complex conditioning environments. [ABSTRACT FROM AUTHOR]
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- 2019
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35. Reward-based crowdfunding success: decomposition of the project, product category, entrepreneur, and location effects.
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Chan, C.S. Richard, Park, Haemin Dennis, Patel, Pankaj, and Gomulya, David
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CROWD funding ,ENTREPRENEURSHIP ,VENTURE capital ,VECTOR error-correction models ,PROJECT finance - Abstract
We assess the relative importance of project, product category, entrepreneur, and location effects on reward-based crowdfunding success. Applying variance decomposition analysis to a sample of 98,336 crowdfunding projects launched between May 2009 and May 2014 on the Kickstarter platform, we find that agency factors, specifically the project and entrepreneur effects, explain the highest relative variance (over 80% of total variance) across three crowdfunding success outcomes - pledge amount, number of backers, and funding success. Structural factors, specifically product category and location effects, have lower but still significant effects. Our study extends prior variance decomposition studies in strategy and entrepreneurship research by incorporating location effects and examining the nascent stage of firm formation. It also contributes to crowdfunding research by providing a systematic framework to compare key determinants of reward-based crowdfunding outcomes. The findings are of practical relevance to aspiring entrepreneurs seeking funding through reward-based crowdfunding platforms. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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36. M-dwarf exoplanet surface density distribution A log-normal fit from 0.07 to 400 AU.
- Author
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Meyer, Michael R., Amara, Adam, Reggiani, Maddalena, and Quanz, Sascha P.
- Abstract
Aims. We fit a log-normal function to the M-dwarf orbital surface density distribution of gas giant planets, over the mass range 1–10 times that of Jupiter, from 0.07 to 400 AU. Methods. We used a Markov chain Monte Carlo approach to explore the likelihoods of various parameter values consistent with point estimates of the data given our assumed functional form. Results. This fit is consistent with radial velocity, microlensing, and direct-imaging observations, is well-motivated from theoretical and phenomenological points of view, and predicts results of future surveys. We present probability distributions for each parameter and a maximum likelihood estimate solution. Conclusions. We suggest that this function makes more physical sense than other widely used functions, and we explore the implications of our results on the design of future exoplanet surveys. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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37. A wide-orbit giant planet in the high-mass b Centauri binary system
- Author
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Markus Janson, Raffaele Gratton, Laetitia Rodet, Arthur Vigan, Mickaël Bonnefoy, Philippe Delorme, Eric E. Mamajek, Sabine Reffert, Lukas Stock, Gabriel-Dominique Marleau, Maud Langlois, Gaël Chauvin, Silvano Desidera, Simon Ringqvist, Lucio Mayer, Gayathri Viswanath, Vito Squicciarini, Michael R. Meyer, Matthias Samland, Simon Petrus, Ravit Helled, Matthew A. Kenworthy, Sascha P. Quanz, Beth Biller, Thomas Henning, Dino Mesa, Natalia Engler, Joseph C. Carson, University of Zurich, Janson, Markus, Stockholm University, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg] = Heidelberg University, Institut für Astronomie und Astrophysik [Tübingen] (IAAT), Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Franco-Chilien d'Astronomie (LFCA), Universidad de Chile = University of Chile [Santiago] (UCHILE)-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción - University of Concepcion [Chile], Universität Zürich [Zürich] = University of Zurich (UZH), Leiden Observatory [Leiden], Universiteit Leiden, SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,1000 Multidisciplinary ,astro-ph.SR ,Multidisciplinary ,530 Physics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Earth and planetary astrophysics ,Astrophysics - solar and stellar astrophysics ,[SDU]Sciences of the Universe [physics] ,10231 Institute for Computational Science ,astro-ph.EP ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
Planet formation occurs around a wide range of stellar masses and stellar system architectures. An improved understanding of the formation process can be achieved by studying it across the full parameter space, particularly toward the extremes. Earlier studies of planets in close-in orbits around high-mass stars have revealed an increase in giant planet frequency with increasing stellar mass until a turnover point at 1.9 solar masses, above which the frequency rapidly decreases. This could potentially imply that planet formation is impeded around more massive stars, and that giant planets around stars exceeding 3 solar masses may be rare or non-existent. However, the methods used to detect planets in small orbits are insensitive to planets in wide orbits. Here we demonstrate the existence of a planet at 560 times the Sun-Earth distance from the 6-10 solar mass binary b Centauri through direct imaging. The planet-to-star mass ratio of 0.10-0.17% is similar to the Jupiter-Sun ratio, but the separation of the detected planet is ~100 times wider than that of Jupiter. Our results show that planets can reside in much more massive stellar systems than what would be expected from extrapolation of previous results. The planet is unlikely to have formed in-situ through the conventional core accretion mechanism, but might have formed elsewhere and arrived to its present location through dynamical interactions, or might have formed via gravitational instability., Comment: Manuscript version. Published in Nature 9 December 2021
- Published
- 2021
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38. Dynamical models to explain observations with SPHERE in planetary systems with double debris belts.
- Author
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Lazzoni, C., Desidera, S., Marzari, F., Boccaletti, A., Langlois, M., Mesa, D., Gratton, R., Kral, Q., Pawellek, N., Olofsson, J., Bonnefoy, M., Chauvin, G., Lagrange, A. M., Vigan, A., Sissa, E., Antichi, J., Avenhaus, H., Baruffolo, A., Baudino, J. L., and Bazzon, A.
- Subjects
SPECTRAL energy distribution ,PLANETARY systems ,ASTRONOMICAL observations ,EXTRASOLAR planets ,VERY large telescopes - Abstract
A large number of systems harboring a debris disk show evidence for a double belt architecture. One hypothesis for explaining the gap between the debris belts in these disks is the presence of one or more planets dynamically carving it. For this reason these disks represent prime targets for searching planets using direct imaging instruments, like the Spectro-Polarimetric High-constrast Exoplanet Research (SPHERE) at the Very Large Telescope. Aims. The goal of this work is to investigate this scenario in systems harboring debris disks divided into two components, placed, respectively, in the inner and outer parts of the system. All the targets in the sample were observed with the SPHERE instrument, which performs highcontrast direct imaging, during the SHINE guaranteed time observations. Positions of the inner and outer belts were estimated by spectral energy distribution fitting of the infrared excesses or, when available, from resolved images of the disk. Very few planets have been observed so far in debris disks gaps and we intended to test if such non-detections depend on the observational limits of the present instruments. This aim is achieved by deriving theoretical predictions of masses, eccentricities and semi-major axes of planets able to open the observed gaps and comparing such parameters with detection limits obtained with SPHERE. Methods. The relation between the gap and the planet is due to the chaotic zone neighboring the orbit of the planet. The radial extent of this zone depends on the mass ratio between the planet and the star, on the semi-major axis and on the eccentricity of the planet and it can be estimated analytically. We first tested the di erent analytical predictions using a numerical tool for the detection of chaotic behavior and then selected the best formula for estimating a planet's physical and dynamical properties required to open the observed gap. We then apply the formalism to the case of one single planet on a circular or eccentric orbit. We then consider multi-planetary systems: two and three equal-mass planets on circular orbits and two equal-mass planets on eccentric orbits in a packed configuration. As a final step, we compare each couple of values (Mp, ap), derived from the dynamical analysis of single and multiple planetary models, with the detection limits obtained with SPHERE. Results. For one single planet on a circular orbit we obtain conclusive results that allow us to exclude such a hypothesis since in most cases this configuration requires massive planets which should have been detected by our observations. Unsatisfactory is also the case of one single planet on an eccentric orbit for which we obtained high masses and/or eccentricities which are still at odds with observations. Introducing multi planetary architectures is encouraging because for the case of three packed equal-mass planets on circular orbits we obtain quite low masses for the perturbing planets which would remain undetected by our SPHERE observations. The case of two equal-mass planets on eccentric orbits is also of interest since it suggests the possible presence of planets with masses lower than the detection limits and with moderate eccentricity. Our results show that the apparent lack of planets in gaps between double belts could be explained by the presence of a system of two or more planets possibly of low mass and on eccentric orbits whose sizes are below the present detection limits. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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39. Real-time gaze estimation via pupil center tracking.
- Author
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Cazzato, Dario, Dominio, Fabio, Manduchi, Roberto, and Castro, Silvia M.
- Subjects
HUMAN-computer interaction ,GAZE ,HUMAN behavior ,EYE tracking ,REGRESSION trees - Abstract
Automatic gaze estimation not based on commercial and expensive eye tracking hardware solutions can enable several applications in the fields of humancomputer interaction (HCI) and human behavior analysis. It is therefore not surprising that several related techniques and methods have been investigated in recent years. However, very few camera-based systems proposed in the literature are both real-time and robust. In thiswork, we propose a real-time user-calibration-free gaze estimation system that does not need person-dependent calibration, can deal with illumination changes and head pose variations, and can work with a wide range of distances from the camera. Our solution is based on a 3-D appearance-based method that processes the images from a built-in laptop camera. Real-time performance is obtained by combining head pose information with geometrical eye features to train a machine learning algorithm. Our method has been validated on a data set of images of users in natural environments, and shows promising results. The possibility of a real-time implementation, combined with the good quality of gaze tracking, make this system suitable for various HCI applications. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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40. Characterization of exoplanets from their formation III. The statistics of planetary luminosities.
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Mordasini, C., Marleau, G.-D., and Mollière, P.
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EXTRASOLAR planets ,STAR formation ,LUMINOSITY ,ASTRONOMICAL observations ,NATURAL satellites - Abstract
Context. A first characterization of extrasolar planets by the observational determination of the radius has recently been achieved for a large number of planets. For some planets, a measurement of the luminosity has also been possible, with many more directly imaged planets expected in the near future. The statistical characterization of exoplanets through their mass-radius and mass-luminosity diagram is becoming possible. This is for planet formation and evolution theory of similar importance as the mass-distance diagram. Aims. Our aim is to extend our planet-formation model into a coupled formation and evolution model. We want to calculate from one single model in a self-consistent way all basic quantities describing a planet: its mass, semimajor axis, composition, radius, and luminosity. We then want to use this model for population synthesis calculations. Methods. In this and a companion paper, we show how we solve the structure equations describing the gaseous envelope of a protoplanet during the early-formation phase, the gas runaway accretion phase, and the evolutionary phase at constant mass on Gyr timescales. We improve the model further with a new prescription for the disk-limited gas accretion rate, an internal structure model for the planetary core assuming a differentiated interior, and the inclusion of radioactive decay as an additional heat source in the core. Results. We study the in situ formation and evolution of Jupiter, the mass-radius relationship of giant planets, the influence of the core mass on the radius, and the luminosity both in the "hot start" and the "cold start" scenario. Special emphasis is placed on the validation of the model by comparing it with other models of planet formation and evolution. We find that our results agree very well with those of more complex models, despite a number of simplifications we make in our calculations. Conclusions. The upgraded model yields the most important physical quantities describing a planet from its beginning as a tiny seed embryo to a Gyr-old planet. This is the case for all planets in a synthetic planetary population. Therefore, we can now use self-consistently the observational constraints coming from all major observational techniques. This is important in a time where different techniques yield constraints on very diverse sub-populations of planets, and where it is difficult to put all these constraints together in one coherent picture. Our comprehensive formation and evolution model should be helpful in this situation for the understanding of exoplanets. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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41. Anthropometry of Brazilian Air Force pilots.
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da Silva, Gilvan V., Halpern, Manny, and Gordon, Claire C.
- Subjects
AIRPLANE equipment ,AIR pilots ,ANTHROPOMETRY ,COMPUTER simulation ,ERGONOMICS ,MEDICAL protocols ,SEX distribution ,MILITARY personnel ,SURVEYS - Abstract
Anthropometric data are essential for the design of military equipment including sizing of aircraft cockpits and personal gear. Currently, there are no anthropometric databases specific to Brazilian military personnel. The aim of this study was to create a Brazilian anthropometric database of Air Force pilots. The methods, protocols, descriptions, definitions, landmarks, tools and measurements procedures followed the instructions outlined in Measurer’s Handbook: US Army and Marine Corps Anthropometric Surveys, 2010–2011 – NATICK/TR-11/017. The participants were measured countrywide, in all five Brazilian Geographical Regions. Thirty-nine anthropometric measurements related to cockpit design were selected. The results of 2133 males and 206 females aged 16–52 years constitute a set of basic data for cockpit design, space arrangement issues and adjustments, protective gear and equipment design, as well as for digital human modelling. Another important implication is that this study can be considered a starting point for reducing gender bias in women’s career as pilots. Practitioner Summary:This paper describes the first large-scale anthropometric survey of the Brazilian Air Force pilots and the development of the related database. This study provides critical data for improving aircraft cockpit design for ergonomics and comprehensive pilot accommodation, protective gear and uniform design, as well as digital human modelling. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
42. Development of seating accommodation models for soldiers in vehicles.
- Author
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Zerehsaz, Yaser, Jin, Jionghua (Judy), Ebert, Sheila M., and Reed, Matthew P.
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INTERIOR decoration ,ANTHROPOMETRY ,AUTOMOBILE driving ,ERGONOMICS ,LABORATORIES ,PROTECTIVE clothing ,RESEARCH methodology ,MOTOR vehicles ,POSTURE ,REGRESSION analysis ,MILITARY personnel ,STATISTICAL models - Abstract
Data from a previous study of soldier driving postures and seating positions were analysed to develop statistical models for defining accommodation of driver seating positions in military vehicles. Regression models were created for seating accommodation applicable to driver positions with a fixed heel point and a range of steering wheel locations in typical tactical vehicles. The models predict the driver-selected seat position as a function of population anthropometry and vehicle layout. These models are the first driver accommodation models considering the effects of body armor and body-borne gear. The obtained results can benefit the design of military vehicles, and the methods can also be extended to be utilised in the development of seating accommodation models for other driving environments where protective equipment affects driver seating posture, such as vehicles used by law-enforcement officers and firefighters. Practitioner Summary:A large-scale laboratory study of soldier driving posture and seating position was designed to focus on tactical vehicle (truck) designs. Regression techniques are utilised to develop accommodation models suitable for tactical vehicles. These are the first seating accommodation models based on soldier data to consider the effects of personal protective equipment and body-borne gear. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
43. El “eterno retorno" de los esencialismos psicológicos: Los “indicios" del carácter.
- Author
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CHRISTIANSEN, MARÍA and VELÁZQUEZ DELGADO, GRACIELA
- Subjects
HUMAN behavior ,CRANIOLOGY ,HYPOTHESIS ,PSEUDOSCIENCE ,PHYSIOGNOMY ,PHYSIOLOGY - Abstract
Copyright of Revista Austral de Ciencias Sociales is the property of Facultad de Filosofia y Humanidades, Intituto de Ciencias Sociales, Universidad Austral de Chile and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2016
44. Improving Perceptions of the Insurance Industry: The Influence of Insurance Professionals.
- Author
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Karl, J. Bradley and Wells, Brenda
- Subjects
INSURANCE company personnel ,EMPLOYEE recruitment ,LABOR market research ,LABOR supply ,HUMAN capital - Abstract
The 'talent crisis' in the insurance industry is well documented. Solutions to this crisis, however, are not plentiful. One of the major challenges faced by the industry is its reputation. We hypothesize that opinions of the industry can be changed through brief but specific education efforts. We test our hypothesis at a major university and find very strong support for our hypothesis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
45. A Possible Dynamical History for the Fomalhaut System.
- Author
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Faramaz, Virginie
- Abstract
Fomalhaut b was long thought to shape the eccentric debris belt in the Fomalhaut system, but its orbit was found to be too eccentric for it to be the dominant belt-shaping perturber. This indicates that Fomalhaut b is Earth-sized at most and that the belt-shaping perturber, hereafter named Fomalhaut c, remains to be discovered. In addition, since its orbit more or less crosses that of Fomalhaut b, it also indicates that the current configuration of the system is transient and was reached recently. In this talk, we show that this current configuration can be explained if Fomalhaut c is Saturn- to Neptune-sized, and Fomalhaut b originates from a mean-motion resonance with Fomalhaut c. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. 1,2,3-Dithiazoles – new reversible melanin synthesis inhibitors: a chemical genomics study.
- Author
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Charalambous, Anna, Koyioni, Maria, Antoniades, Ioanna, Pegeioti, Despoina, Eleftheriou, Iro, Michaelidou, Sophia S., Amelichev, Stanislav A., Konstantinova, Lidia S., Rakitin, Oleg A., Koutentis, Panayiotis A., and Skourides, Paris A.
- Published
- 2015
- Full Text
- View/download PDF
47. PTEN inhibits PREX2-catalyzed activation of RAC1 to restrain tumor cell invasion.
- Author
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Mense, Sarah M., Hodakoski, Cindy, Su, William, Hopkins, Benjamin D., Parsons, Ramon, Barrows, Douglas, Steinbach, Nicole, Schoenfeld, David, Tao Su, Hanina Hibshoosh, and Fine, Barry
- Published
- 2015
- Full Text
- View/download PDF
48. High-contrast imaging with Spitzer: deep observations of Vega, Fomalhaut, and ∊ Eridani.
- Author
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Janson, Markus, Quanz, Sascha P., Carson, Joseph C., Thalmann, Christian, Lafrenière, David, and Amara, Adam
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EXTRASOLAR planets ,BRIGHTEST stars ,SPACE debris ,DISKS (Astrophysics) ,VARIABLE stars ,JUPITER (Planet) ,ASTRONOMICAL image processing - Abstract
Stars with debris disks are intriguing targets for direct-imaging exoplanet searches, owing both to previous detections of wide planets in debris disk systems, and to commonly existing morphological features in the disks themselves that may be indicative of a planetary influence. Here we present observations of three of the most nearby young stars, which are also known to host massive debris disks: Vega, Fomalhaut, and ∊ Eri. The Spitzer Space Telescope is used at a range of orientation angles for each star to supply a deep contrast through angular differential imaging combined with high-contrast algorithms. The observations provide the opportunity to probe substantially colder bound planets (120-330 K) than is possible with any other technique or instrument. For Vega, some apparently very red candidate point sources detected in the 4.5 Ìm image remain to be tested for common proper motion. The images are sensitive to ~2 M
jup companions at 150 AU in this system. The observations presented here represent the first search for planets around Vega using Spitzer. The upper 4.5 μm flux limit on Fomalhaut b could be further constrained relative to previous data. In the case of ∊ Eri, planets below both the effective temperature and the mass of Jupiter could be probed from 80 AU and outward, although no such planets were found. The data sensitively probe the regions around the edges of the debris rings in the systems where planets can be expected to reside. These observations validate previous results showing that more than an order of magnitude improvement in performance in the contrast-limited regime can be acquired with respect to conventional methods by applying sophisticated high-contrast techniques to space-based telescopes, thanks to the high degree of PSF stability provided in this environment. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
49. Insights on the dynamical history of the Fomalhaut system.
- Author
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Faramaz, V., Beust, H., Augereau, J.-C., Kalas, P., and Graham, J. R.
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CIRCUMSTELLAR matter ,CELESTIAL mechanics ,PLANETARY orbits ,MASS (Physics) - Abstract
Context. The eccentric shape of the debris disk observed around the star Fomalhaut was first attributed to Fom b, a companion detected near the belt inner edge, but new constraints on its orbit revealed that it is belt-crossing, highly eccentric (e ~ 0.6-0.9), and can hardly account for the shape of the belt. The best scenario to explain this paradox is that there is another massive body in this system, Fomc, which drives the debris disk shape. The resulting planetary system is highly unstable, which hints at a dynamical scenario involving a recent scattering of Fom b on its current orbit, potentially with the putative Fom c. Aims. Our goal is to give insights on the probability for Fomb to have been set on its highly eccentric orbit by a close encounter with the putative Fom c. We aim to study in particular the part played by mean-motion resonances with Fom c, which could have brought Fom b sufficiently close to Fomc for it to be scattered on its current orbit, but also delay this scattering event. Methods. We assumed that Fomc is much more massive than Fom b, that is, Fom b behaves as a massless test particle compared to Fomc. This allowed us to use N-body numerical simulations and to study the influence of a fixed orbit Fom c on a population of massless test particles, that is, to study the generation of Fomb-like orbits by direct scattering events or via mean-motion resonance processes. We assumed that Fomb originated from an orbit inner to that of the putative Fomc. Results. We found that the generation of orbits similar to that of Fom b, either in terms of dimensions or orientation, is a robust process involving a scattering event and a further secular evolution of inner material with an eccentric massive body such as the putative Fom c. We found in particular that mean-motion resonances can delay scattering events, and thus the production of Fom b-like orbits, on timescales comparable to the age of the system, thus explaining the witnessing of an unstable configuration. Conclusions. We conclude that Fom b probably originated from an inner resonance with a Neptune-Saturn mass Fom c, and was set on its current orbit by a scattering event with Fomc. Since Fomb could not have formed from material in resonance, our scenario also hints at former migration processes in this planetary system. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
50. Planets around stars in young nearby associations Radial velocity searches: a feasibility study and first results.
- Author
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Lagrange, A.-M., Meunier, N., Chauvin, G., Sterzik, M., Galland, F., Lo Curto, G., Rameau, J., and Sosnowska, D.
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PLANETS ,RADIAL velocity of stars ,FEASIBILITY studies ,IMAGING systems in astronomy ,STELLAR activity ,ACQUISITION of data - Abstract
Context. Stars in young nearby associations are the only targets that allow giant planet searches in the near future, at all separations by coupling indirect techniques, such as radial velocity (RV) and deep imaging. These stars are first priority targets for the forthcoming planet imagers on eight- to ten-metre class telescopes. Young stars rotate more rapidly and are more active than their older counterparts. Both effects can limit the ability to detect planets using RV. Aims. We wish to explore the planet detection abilities of a representative sample of stars in close and young associations with RV data and to explore the complementarity between this technique and direct imaging. Methods. We observed 26 such targets with spectral types from A to K and ages from 8 to 300 Myr with HARPS. We computed the detection limits with two methods, in particular, a method we have recently developed that takes the frequency distribution of the RV variations into account. We also attempted to improve the detection limits in a few cases by correcting for the stellar activity. Results. Our A-type stars RV show high-frequency variations due to pulsations, while our F-K stars clearly show activity with more or less complex patterns. For F-K stars, the RV jitter and v sin i rapidly decrease with star age. The data allow us to search for planets with periods typically ranging from 1 day to 100 days, and up to more than 500 days in a few cases. Within the present detection limits, no planet was found in our sample. For the bulk of our F-K stars, the detection limits fall to sub-Jupiter masses. We show that these limits can be significantly improved by correcting even partially for stellar activity, down to a few Neptune masses for the least active stars. The detection limits on A-type stars can be significantly improved, down to a few Jupiter-mass planets, provided an appropriate observing strategy. We finally show the tremendous potential of coupling RV and adaptive-optics deep imaging results. Conclusions. The RV technique allows the detection of planets lighter than Jupiter, reaching a few Neptune masses around young stars aged typically 30 Myr or more. Detection limits increase at younger ages, but (sub-)Jupiter mass planets are still detectable. In the next few years, using complementary techniques will allow a full exploration of the Jupiter-mass planets' content of many of these stars. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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