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7. Implications of the delayed 2013 outburst of the ESO 243-49 HLX-1

Author

Godet, O., Lombardi, J., Antonini, F., Webb, N. A., Barret, D., Vingless, J., and Thomas, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

After showing four outbursts spaced by $\sim 1$ year from 2009 to 2012, the hyper luminous X-ray source ESO 243-49 HLX-1, currently the best intermediate mass black hole (IMBH) candidate, showed an outburst in 2013 delayed by more than a month. In Lasota et al. (2011), we proposed that the X-ray lightcurve is the result of enhanced mass transfer episodes at periapsis from a donor star orbiting the IMBH in a highly eccentric orbit. In this scenario, the delay can be explained only if the orbital parameters can change suddenly from orbit to orbit. To investigate this, we ran Newtonian smooth particle hydrodynamical simulations starting with an incoming donor approaching an IMBH on a parabolic orbit. We survey a large parameter space by varying the star-to-BH mass ratio ($10^{-5}-10^{-3}$) and the periapsis separation $r_p$ from 2.2 to $2.7~r_t$ with $r_t$, the tidal radius. To model the donor, we choose several polytropes ($\Gamma = 5/2,~n=3/2$; $\Gamma=3/2,~n=2$; $\Gamma=5/3,~n=2$ & $n=3$). Once the system is formed, the orbital period decreases until reaching a minimum. Then, the period tends to increase over several periapsis passages due to tidal effects and increasing mass transfer, leading ultimately to the ejection of the donor. The development of stochastic fluctuations inside the donor could lead to sudden changes in the orbital period from orbit to orbit with the appropriate order of magnitude of what has been observed for HLX-1. Given the constraints on the BH mass ($M_{\rm BH} > 10^4~M_\odot$) and assuming that HLX-1 is currently near a minimum in period of $\sim 1$ yr, the donor has to be a white dwarf or a stripped giant core. We predict that if HLX-1 is indeed emerging from a minimum in orbital period, then the period would generally increase with each passage, although substantial stochastic fluctuations can be superposed on this trend., Comment: 22 pages, 10 figures, accepted for publication in ApJ (acceptance date: 2014-08-01)

Published
2014
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8. On the origin of the metallicity dependence in dynamically formed extragalactic low-mass X-ray binaries

Author

Ivanova, N., Fragos, T., Kim, D. -W., Fabbiano, G., Nandez, J. L. Avendano, Lombardi, J. C., Sivakoff, G. R., Voss, R., and Jordan, A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract

Globular clusters (GCs) effectively produce dynamically-formed low-mass X-ray binaries (LMXBs). Observers detect ~100 times more LMXBs per stellar mass in GCs compared to stars in the fields of galaxies. It has also been observationally established that metal-rich GCs are about 3 times more likely to contain an X-ray source than their metal-poor counterparts. Recent observations have shown that this ratio holds in extragalactic GCs for all bright X-ray sources with Lx between 2X10^{37} and 5X10^{38} erg/s. In this Letter, we propose that the observed metallicity dependence of LMXBs in extragalactic GCs can be explained by the differences in the number densities and average masses of red giants in populations of different metallicities. Red giants serve as seeds for the dynamical production of bright LMXBs via two channels - binary exchanges and physical collisions - and the increase of the number densities and masses of red giants boost LMXB production, leading to the observed difference. We also discuss a possible effect of the age difference in stellar populations of different metallicities., Comment: 5 pages, 2 figures, submitted to ApJL

Published
2012
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16. Mixing in massive stellar mergers

Author

Gaburov, E., Lombardi, J. C., and Zwart, S. Portegies

Subjects
Astrophysics
Abstract

The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynamic simulations in three dimensions. We present a computationally inexpensive method in which we approximate the merger process, including shock heating, hydrodynamic mixing and mass loss, with a simple algorithm based on conservation laws and a basic qualitative understanding of the hydrodynamics of stellar mergers. The algorithm relies on Archimedes' principle to dictate the distribution of the fluid in the stable equilibrium situation. We calibrate and apply the method to mergers of massive stars, as these are expected to occur in young and dense star clusters. We find that without the effects of microscopic mixing, the temperature and chemical composition profiles in a collision product can become double-valued functions of enclosed mass. Such an unphysical situation is mended by simulating microscopic mixing as a post-collision effect. In this way we find that head-on collisions between stars of the same spectral type result in substantial mixing, while mergers between stars of different spectral type, such as type B and O stars ($\sim$10 and $\sim$40\msun respectively), are subject to relatively little hydrodynamic mixing., Comment: Accepted by MNRAS

Published
2007
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17. Cerebellar and subcortical atrophy contribute to psychiatric symptoms in frontotemporal dementia

Author

Bussy, A., Levy, J., Best, T., Patel, R., Cupo, L., Van Langenhove, T., Nielsen, J., Pijnenburg, Y., Waldö, M., Remes, A., Schroeter, M., Santana, I., Pasquier, F., Otto, M., Danek, A., Levin, J., Le Ber, I., Vandenberghe, R., Synofzik, M., Moreno, F., de Mendonça, A., Sanchez‐Valle, R., Laforce, R., Langheinrich, T., Gerhard, A., Graff, C., Butler, C., Sorbi, S., Jiskoot, L., Seelaar, H., van Swieten, J., Finger, E., Tartaglia, M., Masellis, M., Tiraboschi, P., Galimberti, D., Borroni, B., Rowe, J., Bocchetta, M., Rohrer, J., Devenyi, G., Chakravarty, M., Ducharme, S., Esteve, A., Nelson, A., Bouzigues, A., Heller, C., Greaves, C., Cash, D., Thomas, D., Todd, E., Benotmane, H., Zetterberg, H., Swift, I., Nicholas, J., Samra, K., Russell, L., Shafei, R., Convery, R., Timberlake, C., Cope, T., Rittman, T., Benussi, A., Premi, E., Gasparotti, R., Archetti, S., Gazzina, S., Cantoni, V., Arighi, A., Fenoglio, C., Scarpini, E., Fumagalli, G., Borracci, V., Rossi, G., Giaccone, G., Di Fede, G., Caroppo, P., Prioni, S., Redaelli, V., Tang‐Wai, D., Rogaeva, E., Castelo‐Branco, M., Freedman, M., Keren, R., Black, S., Mitchell, S., Shoesmith, C., Bartha, R., Rademakers, R., Poos, J., Papma, J., Giannini, L., van Minkelen, R., Nacmias, B., Ferrari, C., Polito, C., Lombardi, G., Bessi, V., Veldsman, M., Andersson, C., Thonberg, H., Öijerstedt, L., Jelic, V., Thompson, P., Lladó, A., Antonell, A., Olives, J., Balasa, M., Bargalló, N., Borrego‐Ecija, S., Verdelho, A., Maruta, C., Ferreira, C., Miltenberger, G., do Couto, F., Gabilondo, A., Gorostidi, A., Villanua, J., Cañada, M., Tainta, M., Zulaica, M., Barandiaran, M., Alves, P., Bender, B., Wilke, C., Graf, L., Vogels, A., Vandenbulcke, M., Van Damme, P., Bruffaerts, R., Poesen, K., Rosa‐Neto, P., Gauthier, S., Camuzat, A., Brice, A., Bertrand, A., Funkiewiez, A., Rinaldi, D., Saracino, D., Colliot, O., Sayah, S., Prix, C., Wlasich, E., Wagemann, O., Loosli, S., Schönecker, S., Hoegen, T., Lombardi, J., Anderl‐Straub, S., Rollin, A., Kuchcinski, G., Bertoux, M., Lebouvier, T., Deramecourt, V., Santiago, B., Duro, D., Leitão, M., Almeida, M., Tábuas‐Pereira, M., Afonso, S., Engel, A., Polyakova, M., Erasmus MC other, Neurology, Radiology & Nuclear Medicine, Clinical Genetics, GENetic Frontotemporal dementia Initiative (GENFI), Lombardi, Gemma, Bessi, Valentina, Veldsman, Michele, Andersson, Christin, Thonberg, Hakan, Öijerstedt, Linn, Jelic, Vesna, Thompson, Paul, Langheinrich, Tobias, Lladó, Albert, Antonell, Anna, Olives, Jaume, Balasa, Mircea, Bargalló, Nuria, Borrego-Ecija, Sergi, Verdelho, Ana, Maruta, Carolina, Ferreira, Catarina B, Miltenberger, Gabriel, do Couto, Frederico Simões, Gabilondo, Alazne, Gorostidi, Ana, Villanua, Jorge, Cañada, Marta, Tainta, Mikel, Zulaica, Miren, Barandiaran, Myriam, Alves, Patricia, Bender, Benjamin, Wilke, Carlo, Graf, Lisa, Vogels, Annick, Vandenbulcke, Mathieu, Van Damme, Philip, Bruffaerts, Rose, Poesen, Koen, Rosa-Neto, Pedro, Gauthier, Serge, Camuzat, Agnès, Brice, Alexis, Bertrand, Anne, Funkiewiez, Aurélie, Rinaldi, Daisy, Saracino, Dario, Colliot, Olivier, Sayah, Sabrina, Prix, Catharina, Wlasich, Elisabeth, Wagemann, Olivia, Loosli, Sandra, Schönecker, Sonja, Hoegen, Tobias, Lombardi, Jolina, Anderl-Straub, Sarah, Rollin, Adeline, Kuchcinski, Gregory, Bertoux, Maxime, Lebouvier, Thibaud, Deramecourt, Vincent, Santiago, Beatriz, Duro, Diana, Leitão, Maria João, Almeida, Maria Rosario, Tábuas-Pereira, Miguel, Afonso, Sónia, Engel, Annerose, Polyakova, Maryna, Esteve, Aitana Sogorb, Nelson, Annabel, Bouzigues, Arabella, Heller, Carolin, Greaves, Caroline V, Cash, David, Thomas, David L, Todd, Emily, Benotmane, Hanya, Zetterberg, Henrik, Swift, Imogen J, Nicholas, Jennifer, Samra, Kiran, Russell, Lucy L, Bocchetta, Martina, Shafei, Rachelle, Convery, Rhian S, Timberlake, Carolyn, Cope, Thomas, Rittman, Timothy, Benussi, Alberto, Premi, Enrico, Gasparotti, Roberto, Archetti, Silvana, Gazzina, Stefano, Cantoni, Valentina, Arighi, Andrea, Fenoglio, Chiara, Scarpini, Elio, Fumagalli, Giorgio, Borracci, Vittoria, Rossi, Giacomina, Giaccone, Giorgio, Di Fede, Giuseppe, Caroppo, Paola, Tiraboschi, Pietro, Prioni, Sara, Redaelli, Veronica, Tang-Wai, David, Rogaeva, Ekaterina, Castelo-Branco, Miguel, Freedman, Morris, Keren, Ron, Black, Sandra, Mitchell, Sara, Shoesmith, Christen, Bartha, Robart, Rademakers, Rosa, Poos, Jackie, Papma, Janne M, Giannini, Lucia, van Minkelen, Rick, Pijnenburg, Yolande, Nacmias, Benedetta, Ferrari, Camilla, Polito, Cristina, Bussy, Aurélie [0000-0001-6695-9941], Nielsen, Jørgen E [0000-0003-0453-5582], Borroni, Barbara [0000-0001-9340-9814], Bocchetta, Martina [0000-0003-1814-5024], Devenyi, Gabriel A [0000-0002-7766-1187], Apollo - University of Cambridge Repository, and Amsterdam Neuroscience - Neurodegeneration

Subjects
C9orf72 Protein, Radiological and Ultrasound Technology, Medizin, frontotemporal dementia, Neurology, Frontotemporal Dementia, Cerebellum, Humans, magnetic resonance imaging, genetics, neuropsychiatry, Radiology, Nuclear Medicine and imaging, Human medicine, ddc:610, Neurology (clinical), Atrophy, Anatomy, genetics [Frontotemporal Dementia], genetics [C9orf72 Protein]
Abstract

Funder: Alzheimer Society of Canada; Id: http://dx.doi.org/10.13039/501100000143, Funder: Weston Brain Institute; Id: http://dx.doi.org/10.13039/100012479, Funder: Fonds de Recherche du Québec ‐ Santé, Funder: Canadian Institutes of Health Research; Id: http://dx.doi.org/10.13039/501100000024, Funder: NIHR Rare Diseases Translational Research Collaboration, Funder: Deutsche Forschungsgemeinschaft; Id: http://dx.doi.org/10.13039/501100001659, Recent studies have reported early cerebellar and subcortical impact in the disease progression of genetic frontotemporal dementia (FTD) due to microtubule-associated protein tau (MAPT), progranulin (GRN) and chromosome 9 open reading frame 72 (C9orf72). However, the cerebello-subcortical circuitry in FTD has been understudied despite its essential role in cognition and behaviors related to FTD symptomatology. The present study aims to investigate the association between cerebellar and subcortical atrophy, and neuropsychiatric symptoms across genetic mutations. Our study included 983 participants from the Genetic Frontotemporal dementia Initiative including mutation carriers and noncarrier first-degree relatives of known symptomatic carriers. Voxel-wise analysis of the thalamus, striatum, globus pallidus, amygdala, and the cerebellum was performed, and partial least squares analyses (PLS) were used to link morphometry and behavior. In presymptomatic C9orf72 expansion carriers, thalamic atrophy was found compared to noncarriers, suggesting the importance of this structure in FTD prodromes. PLS analyses demonstrated that the cerebello-subcortical circuitry is related to neuropsychiatric symptoms, with significant overlap in brain/behavior patterns, but also specificity for each genetic mutation group. The largest differences were in the cerebellar atrophy (larger extent in C9orf72 expansion group) and more prominent amygdalar volume reduction in the MAPT group. Brain scores in the C9orf72 expansion carriers and MAPT carriers demonstrated covariation patterns concordant with atrophy patterns detectable up to 20 years before expected symptom onset. Overall, these results demonstrated the important role of the subcortical structures in genetic FTD symptom expression, particularly the cerebellum in C9orf72 and the amygdala in MAPT carriers.

Published
2023

21. Modest-2: A Summary

Author

Sills, A., Deiters, S., Eggleton, P., Freitag, M., Giersz, M., Heggie, D., Hurley, J., Hut, P., Ivanova, N., Klessen, R., Kroupa, P., Lombardi, J., McMillan, S., Zwart, S. Portegies, and Zinnecker, H.

Subjects
Astrophysics
Abstract

This is a summary paper of MODEST-2, a workshop held at the Astronomical Institute ``Anton Pannekoek'' in Amsterdam, 16-17 December 2002. MODEST is a loose collaboration of people interested in MOdelling DEnse STellar systems, particularly those interested in modelling these systems using all the available physics (stellar dynamics, stellar evolution, hydrodynamics and the interplay between the three) by defining interfaces between different codes. In this paper, we summarize 1) the main advances in this endeavour since MODEST-1; 2) the main science goals which can be and should be addressed by these types of simulations; and 3) the most pressing theoretical and modelling advances that we identified., Comment: Accepted by New Astronomy

Published
2003
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24. Motor symptoms in genetic frontotemporal dementia: developing a new module for clinical rating scales

Author

Samra, K, MacDougall, AM, Peakman, G, Bouzigues, A, Bocchetta, M, Cash, DM, Greaves, CV, Convery, RS, van Swieten, JC, Jiskoot, L, Seelaar, H, Butler, CR, Fenoglio, C, Rohrer, JD, Gerhard, A, Ducharme, S, Le Ber, I, Tiraboschi, P, Santana, I, Pasquier, F, Levin, J, Shoesmith, C, Otto, M, Russell, LL, Nelson, A, Cash, D, Thomas, DL, Todd, E, Ferrari, C, Benotmane, H, Timberlake, C, Gabilondo, A, Cope, T, Rittman, T, Benussi, A, Premi, E, Gasparotti, R, Thompson, P, Archetti, S, Fumagalli, G, do Couto, FS, Borracci, V, Polito, C, Rossi, G, Giaccone, G, Di Fede, G, Caroppo, P, Ferreira, CB, Prioni, S, Langheinrich, T, Redaelli, V, Lladó, A, Bartha, R, Tang-Wai, D, Rogaeva, E, Castelo-Branco, M, Freedman, M, Keren, R, Black, S, Mitchell, S, Miltenberger, G, Rademakers, R, Poos, J, Papma, JM, Giannini, L, van Minkelen, R, Pijnenburg, Y, Gauthier, S, Nacmias, B, Lombardi, G, Bessi, V, Veldsman, M, Andersson, C, Thonberg, H, Öijerstedt, L, Prix, C, Jelic, V, Antonell, A, Graff, C, Olives, J, Balasa, M, Bargalló, N, Borrego-Ecija, S, Verdelho, A, Kuchcinski, G, Maruta, C, Gorostidi, A, Laforce, R, Villanua, J, Wlasich, E, Cañada, M, Tainta, M, Zulaica, M, Barandiaran, M, Moreno, F, Alves, P, Bender, B, Bertoux, M, Wilke, C, Lebouvier, T, Camuzat, A, Graf, L, Vogels, A, Vandenbulcke, M, Van Damme, P, Bruffaerts, R, Poesen, K, Rosa-Neto, P, Sanchez-Valle, R, Brice, A, Bertrand, A, Funkiewiez, A, Rinaldi, D, Saracino, D, Colliot, O, Sorbi, S, Sayah, S, Wagemann, O, Loosli, S, Schönecker, S, Hoegen, T, Lombardi, J, Anderl-Straub, S, Nicholas, J, Rollin, A, Deramecourt, V, Arighi, A, Santiago, B, Duro, D, Leitão, MJ, Almeida, MR, Tábuas-Pereira, M, Gazzina, S, Afonso, S, Masellis, M, Tartaglia, C, Shafei, R, Rowe, JB, Borroni, B, Finger, E, Synofzik, M, Galimberti, D, Vandenberghe, R, de Mendonça, A, Cantoni, V, Genetic FTD Initiative (GENFI), Samra, Kiran [0000-0002-3105-7099], Apollo - University of Cambridge Repository, Maruta, Carolina, Ferreira, Catarina B, Miltenberger, Gabriel, do Couto, Frederico Simões, Gabilondo, Alazne, Gorostidi, Ana, Villanua, Jorge, Cañada, Marta, Tainta, Mikel, Zulaica, Miren, Barandiaran, Myriam, Alves, Patricia, Bender, Benjamin, Wilke, Carlo, Graf, Lisa, Vogels, Annick, Vandenbulcke, Mathieu, Van Damme, Philip, Bruffaerts, Rose, Poesen, Koen, Rosa-Neto, Pedro, Gauthier, Serge, Camuzat, Agnès, Brice, Alexis, Bertrand, Anne, Funkiewiez, Aurélie, Rinaldi, Daisy, Saracino, Dario, Colliot, Olivier, Sayah, Sabrina, Prix, Catharina, Wlasich, Elisabeth, Wagemann, Olivia, Loosli, Sandra, Schönecker, Sonja, Hoegen, Tobias, Lombardi, Jolina, Anderl-Straub, Sarah, Rollin, Adeline, Kuchcinski, Gregory, Bertoux, Maxime, Lebouvier, Thibaud, Deramecourt, Vincent, Santiago, Beatriz, Duro, Diana, Leitão, Maria João, Almeida, Maria Rosario, Tábuas-Pereira, Miguel, Afonso, Sónia, Nelson, Annabel, Bocchetta, Martina, Cash, David, Thomas, David L, Todd, Emily, Benotmane, Hanya, Nicholas, Jennifer, Samra, Kiran, Shafei, Rachelle, Timberlake, Carolyn, Cope, Thomas, Rittman, Timothy, Benussi, Alberto, Premi, Enrico, Gasparotti, Roberto, Archetti, Silvana, Gazzina, Stefano, Cantoni, Valentina, Arighi, Andrea, Fenoglio, Chiara, Fumagalli, Giorgio, Borracci, Vittoria, Rossi, Giacomina, Giaccone, Giorgio, Di Fede, Giuseppe, Caroppo, Paola, Tiraboschi, Pietro, Prioni, Sara, Redaelli, Veronica, Tang-Wai, David, Rogaeva, Ekaterina, Castelo-Branco, Miguel, Freedman, Morris, Keren, Ron, Black, Sandra, Mitchell, Sara, Shoesmith, Christen, Bartha, Robart, Rademakers, Rosa, Poos, Jackie, Papma, Janne M, Giannini, Lucia, van Minkelen, Rick, Pijnenburg, Yolande, Nacmias, Benedetta, Ferrari, Camilla, Polito, Cristina, Lombardi, Gemma, Bessi, Valentina, Veldsman, Michele, Andersson, Christin, Thonberg, Hakan, Öijerstedt, Linn, Jelic, Vesna, Thompson, Paul, Langheinrich, Tobias, Lladó, Albert, Antonell, Anna, Olives, Jaume, Balasa, Mircea, Bargalló, Nuria, Borrego-Ecija, Sergi, and Verdelho, Ana

Subjects
Progranulin, Clinical Neurology, C9ORF72, tau Proteins, AMYOTROPHIC-LATERAL-SCLEROSIS, diagnosis [Frontotemporal Dementia], C9orf72, Tremor, Genetics, Humans, ddc:610, genetics [Frontotemporal Dementia], genetics [C9orf72 Protein], MUTATION, Science & Technology, C9orf72 Protein, HERITABILITY, Amyotrophic Lateral Sclerosis, PROGRESSIVE SUPRANUCLEAR PALSY, COGNITIVE IMPAIRMENT, REPEAT EXPANSION, genetics [tau Proteins], Motor, PATHOLOGICAL FEATURES, Neurology, FOS: Biological sciences, Frontotemporal Dementia, Mutation, Human medicine, Neurosciences & Neurology, Neurology (clinical), Tau, TAU, Life Sciences & Biomedicine, Frontotemporal dementia, PARKINSONISM
Abstract

Funder: CIBERNED, Funder: Canadian Institutes of Health Research; doi: http://dx.doi.org/10.13039/501100000024, Funder: Lemaire Family Foundation, Funder: Swedish Frontotemporal Dementia Initiative, Funder: Italian Ministry of Health, Funder: Weston Brain Institute; doi: http://dx.doi.org/10.13039/100012479, Funder: Mady Browaaeys Fund, Funder: Miriam Marks Brain Research UK, Funder: Bluefield Project, OBJECTIVE: To investigate the optimal method of adding motor features to a clinical rating scale for frontotemporal dementia (FTD). METHODS: Eight hundred and thirty-two participants from the international multicentre Genetic FTD Initiative (GENFI) study were recruited: 522 mutation carriers (with C9orf72, GRN and MAPT mutations) and 310 mutation-negative controls. A standardised clinical questionnaire was used to assess eight motor symptoms (dysarthria, dysphagia, tremor, slowness, weakness, gait disorder, falls and functional difficulties using hands). Frequency and severity of each motor symptom was assessed, and a principal component analysis (PCA) was performed to identify how the different motor symptoms loaded together. Finally, addition of a motor component to the CDR® plus NACC FTLD was investigated (CDR® plus NACC FTLD-M). RESULTS: 24.3% of mutation carriers had motor symptoms (31.7% C9orf72, 18.8% GRN, 19.3% MAPT) compared to 6.8% of controls. Slowness and gait disorder were the commonest in all genetic groups while tremor and falls were the least frequent. Symptom severity scores were similar to equivalent physical motor examination scores. PCA revealed that all motor symptoms loaded together so a single additional motor component was added to the CDR® plus NACC FTLD to form the CDR® plus NACC FTLD-M. Individual global scores were more severe with the CDR® plus NACC FTLD-M, and no patients with a clinically diagnosed motor disorder (ALS/FTD-ALS or parkinsonism) were classified anymore as asymptomatic (unlike the CDR® plus NACC FTLD alone). CONCLUSIONS: Motor features are present in mutation carriers at all disease stages across all three genetic groups. Inclusion of motor symptoms in a rating scale that can be used in future clinical trials will not only ensure a more accurate severity measure is recorded but that a wider spectrum of FTD phenotypes can be included in the same trial.

Published
2022

26. Collisions of Main-Sequence Stars and the Formation of Blue Stragglers in Globular Clusters

Author

Lombardi, J. C., Rasio, F. A., and Shapiro, S. L.

Subjects
Astrophysics
Abstract

We report the results of new SPH calculations of parabolic collisions between two main-sequence stars in a globular cluster. Such collisions are directly relevant to the formation of blue stragglers. In particular, we consider parent stars of mass $M/M_{TO}=0.2,0.5,0.75$, and $1$, where $M_{TO}$ is the cluster turnoff mass (typically about $0.8\,M_\odot$). Low-mass stars (with $M=0.2 M_{TO}$ or $0.5 M_{TO}$) are assumed to be fully convective and are therefore modeled as $n=1.5$ polytropes. Stars at the turnoff (with $M= M_{TO}$) are assumed to be mostly radiative and are modeled as $n=3$ polytropes. Intermediate-mass stars (with $M=0.75 M_{TO}$) are modeled as composite polytropes consisting of a radiative core with polytropic index $n=3$ and a convective envelope with $n=1.5$. We focus our study on the question of hydrodynamic mixing of helium and hydrogen, which plays a crucial role in determining the observable characteristics of blue stragglers. In all cases we find that there is negligible hydrodynamic mixing of helium into the outer envelope of the merger remnant. The amount of hydrogen mixed into the core of the merger depends strongly on the entropy profiles of the two colliding stars. In contrast to what has been done in previous studies, blue stragglers formed by direct stellar collisions should not necessarily be assumed to have initially homogeneous composition profiles., Comment: uses AAS latex macros v3, 66 pages with tables and figures, submitted to ApJ, complete postscript also available at http://ensor.mit.edu/~rasio/papers

Published
1995
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31. <scp>SNAPSHOT USA</scp> 2020: A second coordinated national camera trap survey of the United States during the <scp>COVID</scp> ‐19 pandemic

Author

Kays R., Cove M. V., Diaz J., Todd K., Bresnan C., Snider M., Lee T. E., Jasper J. G., Douglas B., Crupi A. P., Weiss K. C. B., Rowe H., Sprague T., Schipper J., Lepczyk C. A., Fantle-Lepczyk J. E., Davenport J., Zimova M., Farris Z., Williamson J., Fisher-Reid M. C., Rezendes D., King S. M., Chrysafis P., Jensen A. J., Jachowski D. S., King K. C., Herrera D. J., Moore S., van der Merwe M., Lombardi J. V., Sergeyev M., Tewes M. E., Horan R. V., Rentz M. S., Driver A., Brandt L. R. S. E., Nagy C., Alexander P., Maher S. P., Darracq A. K., Barr E. G., Hess G., Webb S. L., Proctor M. D., Vanek J. P., Lafferty D. J. R., Hubbard T., Jimenez J. E., McCain C., Favreau J., Fogarty J., Hill J., Hammerich S., Gray M., Rega-Brodsky C. C., Durbin C., Flaherty E. A., Brooke J., Coster S. S., Lathrop R. G., Russell K., Bogan D. A., Shamon H., Rooney B., Rockhill A., Lonsinger R. C., O'Mara M. T., Compton J. A., Barthelmess E. L., Andy K. E., Belant J. L., Petroelje T., Wehr N. H., Beyer D. E., Scognamillo D. G., Schalk C., Day K., Ellison C. N., Ruthven C., Nunley B., Fritts S., Whittier C. A., Neiswenter S. A., Pelletier R., DeGregorio B. A., Kuprewicz E. K., Davis M. L., Baruzzi C., Lashley M. A., McDonald B., Mason D., Risch D. R., Allen M. L., Whipple L. S., Sperry J. H., Alexander E., Wolff P. J., Hagen R. H., Mortelliti A., Bolinjcar A., Wilson A. M., Van Norman S., Powell C., Coletto H., Schauss M., Bontrager H., Beasley J., Ellis-Felege S. N., Wehr S. R., Giery S. T., Pekins C. E., LaRose S. H., Revord R. S., Hansen C. P., Hansen L., Millspaugh J. J., Zorn A., Gerber B. D., Rezendes K., Adley J., Sevin J., Green A. M., Sekercioglu C. H., Pendergast M. E., Mullen K., Bird T., Edelman A. J., Romero A., O'Neill B. J., Schmitz N., Vandermus R. A., Alston J. M., Kuhn K. M., Hasstedt S. C., Lesmeister D. B., Appel C. L., Rota C., Stenglein J. L., Anhalt-Depies C., Nelson C. L., Long R. A., Remine K. R., Jordan M. J., Elbroch L. M., Bergman D., Cendejas-Zarelli S., Sager-Fradkin K., Conner M., Morris G., Parsons E., Hernandez-Yanez H., McShea W. J., Kays, R., Cove, M. V., Diaz, J., Todd, K., Bresnan, C., Snider, M., Lee, T. E., Jasper, J. G., Douglas, B., Crupi, A. P., Weiss, K. C. B., Rowe, H., Sprague, T., Schipper, J., Lepczyk, C. A., Fantle-Lepczyk, J. E., Davenport, J., Zimova, M., Farris, Z., Williamson, J., Fisher-Reid, M. C., Rezendes, D., King, S. M., Chrysafis, P., Jensen, A. J., Jachowski, D. S., King, K. C., Herrera, D. J., Moore, S., van der Merwe, M., Lombardi, J. V., Sergeyev, M., Tewes, M. E., Horan, R. V., Rentz, M. S., Driver, A., Brandt, L. R. S. E., Nagy, C., Alexander, P., Maher, S. P., Darracq, A. K., Barr, E. G., Hess, G., Webb, S. L., Proctor, M. D., Vanek, J. P., Lafferty, D. J. R., Hubbard, T., Jimenez, J. E., Mccain, C., Favreau, J., Fogarty, J., Hill, J., Hammerich, S., Gray, M., Rega-Brodsky, C. C., Durbin, C., Flaherty, E. A., Brooke, J., Coster, S. S., Lathrop, R. G., Russell, K., Bogan, D. A., Shamon, H., Rooney, B., Rockhill, A., Lonsinger, R. C., O'Mara, M. T., Compton, J. A., Barthelmess, E. L., Andy, K. E., Belant, J. L., Petroelje, T., Wehr, N. H., Beyer, D. E., Scognamillo, D. G., Schalk, C., Day, K., Ellison, C. N., Ruthven, C., Nunley, B., Fritts, S., Whittier, C. A., Neiswenter, S. A., Pelletier, R., Degregorio, B. A., Kuprewicz, E. K., Davis, M. L., Baruzzi, C., Lashley, M. A., Mcdonald, B., Mason, D., Risch, D. R., Allen, M. L., Whipple, L. S., Sperry, J. H., Alexander, E., Wolff, P. J., Hagen, R. H., Mortelliti, A., Bolinjcar, A., Wilson, A. M., Van Norman, S., Powell, C., Coletto, H., Schauss, M., Bontrager, H., Beasley, J., Ellis-Felege, S. N., Wehr, S. R., Giery, S. T., Pekins, C. E., Larose, S. H., Revord, R. S., Hansen, C. P., Hansen, L., Millspaugh, J. J., Zorn, A., Gerber, B. D., Rezendes, K., Adley, J., Sevin, J., Green, A. M., Sekercioglu, C. H., Pendergast, M. E., Mullen, K., Bird, T., Edelman, A. J., Romero, A., O'Neill, B. J., Schmitz, N., Vandermus, R. A., Alston, J. M., Kuhn, K. M., Hasstedt, S. C., Lesmeister, D. B., Appel, C. L., Rota, C., Stenglein, J. L., Anhalt-Depies, C., Nelson, C. L., Long, R. A., Remine, K. R., Jordan, M. J., Elbroch, L. M., Bergman, D., Cendejas-Zarelli, S., Sager-Fradkin, K., Conner, M., Morris, G., Parsons, E., Hernandez-Yanez, H., and Mcshea, W. J.

Subjects
United State, Carnivora, Wild, mammal, Animals, Wild, Didelphimorphia, species distribution modeling, Birds, Bird, camera traps, biodiversity, biogeography, Cetartiodactyla, Lagomorpha, mammals, occupancy modeling, Animals, Humans, Mammals, Pandemics, United States, COVID-19, Ecology, Evolution, Behavior and Systematics, Pandemic, camera trap, Animal, Human
Abstract

Managing wildlife populations in the face of global change requires regular data on the abundance and distribution of wild animals, but acquiring these over appropriate spatial scales in a sustainable way has proven challenging. Here we present the data from Snapshot USA 2020, a second annual national mammal survey of the USA. This project involved 152 scientists setting camera traps in a standardized protocol at 1485 locations across 103 arrays in 43 states for a total of 52,710 trap-nights of survey effort. Most (58) of these arrays were also sampled during the same months (September and October) in 2019, providing a direct comparison of animal populations in 2 years that includes data from both during and before the COVID-19 pandemic. All data were managed by the eMammal system, with all species identifications checked by at least two reviewers. In total, we recorded 117,415 detections of 78 species of wild mammals, 9236 detections of at least 43 species of birds, 15,851 detections of six domestic animals and 23,825 detections of humans or their vehicles. Spatial differences across arrays explained more variation in the relative abundance than temporal variation across years for all 38 species modeled, although there are examples of significant site-level differences among years for many species. Temporal results show how species allocate their time and can be used to study species interactions, including between humans and wildlife. These data provide a snapshot of the mammal community of the USA for 2020 and will be useful for exploring the drivers of spatial and temporal changes in relative abundance and distribution, and the impacts of species interactions on daily activity patterns. There are no copyright restrictions, and please cite this paper when using these data, or a subset of these data, for publication.

Published
2022

49. THE FIRST 70NM 6-INCH GaAs PHEMT MMIC PROCESS

Author

KARIMY, H., primary, GUNTER, L., additional, DUGAS, D., additional, CHAO, P. C., additional, KONG, W., additional, YANG, S., additional, SEEKELL, P., additional, DUH, K. H. G., additional, LOMBARDI, J., additional, and MT PLEASANT, L., additional

Published
2009
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