5,193 research outputs found
Management of the Sawmill Slough Preserve, University of North Florida
Poster presented at the 2014 Ecological Society of America (ESA) 99th Annual Meeting: From Oceans to Mountains. Sacramento, California.https://digitalcommons.unf.edu/ecenter_presentations/1002/thumbnail.jp
Prospects for detection of detached double white dwarf binaries with Gaia, LSST and LISA
Double white dwarf (DWD) binaries are expected to be very common in the Milky
Way, but their intrinsic faintness challenges the detection of these systems.
Currently, only a few tens of detached DWDs are know. Such systems offer the
best chance of extracting the physical properties that would allow us to
address a wealth of outstanding questions ranging from the nature of white
dwarfs, over stellar and binary evolution to mapping the Galaxy. In this paper
we explore the prospects for detections of ultra-compact (with binary
separations of a few solar radii or less) detached DWDs in: 1) optical
radiation with Gaia and the LSST and 2) gravitational wave radiation with LISA.
We show that Gaia, LSST and LISA have the potential to detect respectively
around a few hundreds, a thousand, and 25 thousand DWD systems. Moreover, Gaia
and LSST data will extend by respectively a factor of two and seven the
guaranteed sample of binaries detected in electromagnetic and gravitational
wave radiation, opening the era of multi-messenger astronomy for these sources.Comment: submitted to MNRA
The Kindred Bonds of Mentally Ill Homeless Persons
While the unraveling of the kinship bond has long been suspected to play a role in the epidemiology of homelessness, the connection between kinship and homelessness has been little studied. Based on a normative analysis of the role of family structure in response to adversity, this article explores the impact of the amount and quality of kinship ties on episodes of homelessness experienced by discharged psychiatric patients in Ohio. Survey data derived from personal interviews with both former patients and their kin indicate more strain in relations with kin of the homeless than the nonhomeless. The strain in the kinship bond appears to emanate from a greater prevalence of chronic disabilities that undermine independent functioning and tax the resources of relatives who choose to remain involved. Consistent with this interpretation, patients with histories of homelessness reported more psychiatric symptoms, more deficits in daily living skills, and more contact with the criminal justice system. In general, patient variables were better able than family variables to differentiate the homeless from the nonhomeless. Nonetheless, the formulation of public policies for reducing the incidence and prevalence of homelessness will surely need to take account of the kinship bond and how it can be strengthened
Phosphoregulation of the cytokinetic protein Fic1 contributes to fission yeast growth polarity establishment
© 2020. Published by The Company of Biologists Ltd. Cellular polarization underlies many facets of cell behavior, including cell growth. The rod-shaped fission yeast Schizosaccharomyces pombe is a well-established, genetically tractable system for studying growth polarity regulation. S. pombe cells elongate at their two cell tips in a cell cycle-controlled manner, transitioning from monopolar to bipolar growth in interphase when new ends established by the most recent cell division begin to extend. We previously identified cytokinesis as a critical regulator of new end growth and demonstrated that Fic1, a cytokinetic factor, is required for normal polarized growth at new ends. Here, we report that Fic1 is phosphorylated on two C-terminal residues, which are each targeted by multiple protein kinases. Endogenously expressed Fic1 phosphomutants cannot support proper bipolar growth, and the resultant defects facilitate the switch into an invasive pseudohyphal state. Thus, phosphoregulation of Fic1 links the completion of cytokinesis to the re-establishment of polarized growth in the next cell cycle. These findings broaden the scope of signaling events that contribute to regulating S. pombe growth polarity, underscoring that cytokinetic factors constitute relevant targets of kinases affecting new end growth.This article has an associated First Person interview with Anthony M. Rossi, joint first author of the paper
Bremsstrahlung Suppression due to the LPM and Dielectric Effects in a Variety of Materials
The cross section for bremsstrahlung from highly relativistic particles is
suppressed due to interference caused by multiple scattering in dense media,
and due to photon interactions with the electrons in all materials. We present
here a detailed study of bremsstrahlung production of 200 keV to 500 MeV
photons from 8 and 25 GeV electrons traversing a variety of target materials.
For most targets, we observe the expected suppressions to a good accuracy. We
observe that finite thickness effects are important for thin targets.Comment: 52 pages, 13 figures (incorporated in the revtex LaTeX file
Influence of the LPM effect and dielectric suppression on particle air showers
An analysis of the influence of the Landau-Migdal-Pomeranchuk (LPM) effect on
the development of air showers initiated by astroparticles is presented. The
theory of Migdal is studied and compared with other theoretical methods,
particularly the Blankenbecler and Drell approach. By means of realistic
computer simulations and using algorithms that emulate Migdal's theory,
including also the so-called dielectric suppression, we study the behavior of
the relevant observables in the case of ultra-high energy primaries. We find
that the LPM effect can significantly modify the development of high energy
electromagnetic showers in certain cases.Comment: 18 pages, 13 figures, 1 table. To appear in Phys. Rev.
Polarized Virtual Photon Structure Function and Twist-3 Effects in QCD
We investigate the twist-3 effects in the polarized virtual photon structure.
The structure functions and of polarized photon could
be experimentally studied in the future polarized or colliders.
The leading contributions to are the twist-2 effects, while
another structure function , which only exists for the virtual
photon target, receives not only the twist-2 but also twist-3 contributions. We
first show that the twist-3 effects actually exist in the box-diagram
contributions and we extract the twist-3 part, which can also be reproduced by
the pure QED operator product expansion. We then calculate the non-trivial
lowest moment () of the twist-3 contribution to in QCD. For
large (the number of colors), the QCD analysis of the twist-3 effects in
the flavor nonsinglet part of becomes tractable and we can obtain
its moments in a compact form for all .Comment: 27 pages, LaTeX, 9 eps figures, eqsection.sty file included, Appendix
A added, some minor changes for Fig.
Propagation of Muons and Taus at High Energies
The photonuclear contribution to charged lepton energy loss has been
re-evaluated taking into account HERA results on real and virtual photon
interactions with nucleons. With large processes incorporated, the
average muon range in rock for muon energies of GeV is reduced by only
5% as compared with the standard treatment. We have calculated the tau energy
loss for energies up to GeV taking into consideration the decay of the
tau. A Monte Carlo evaluation of tau survival probability and range show that
at energies below GeV, depending on the material, only tau decays
are important. At higher energies the tau energy losses are significant,
reducing the survival probability of the tau. We show that the average range
for tau is shorter than its decay length and reduce to 17 km in water for an
incident tau energy of GeV, as compared with its decay length of 49 km
at that energy. In iron, the average tau range is 4.7 km for the same incident
energy.Comment: 25 pages including 8 figure
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