26,691 research outputs found
The 2009 National School Climate Survey: The Experiences of Lesbian, Gay, Bisexual and Transgender Youth in Our Nation's Schools
National survey of the school experiences of 7,261 lesbian, gay, bisexual and trasngender secondary school students.In our 2009 survey, we examine the experiences of LGBT students with regard to indicators of negative school climate:hearing biased remarks, including homophobic remarks, in school;feeling unsafe in school because of personal characteristics, such as sexual orientation, gender expression, or race/ethnicity;missing classes or days of school because of safety reasons; andexperiences of harassment and assault in school. We also examine the possible negative effects of a hostile school climate on LGBT students' academic achievement, educational aspirations, and psychological well-being. We explore the diverse nature of LGBT students' experiences by reporting on how these differ by students' personal and community characteristics. We also examine whether or not students report experiences of victimization to school officials or to family members and how these adults address the problem. In addition, we demonstrate the degree to which LGBT students have access to supportive resources in school, and we explore the possible benefits of these resources, including Gay-Straight Alliances (GSAs), school harassment/assault policies, supportive school staff, and curriculum that is inclusive of LGBT-related topics.Given that we now have 10 years of data, we examine changes over the past decade on both indicators of negative school climate and levels of access to LGBT-related resources in schools
Magnetic frustration in the spinel compounds Ge Co_2 O_4 and Ge Ni_2 O_4
In both spinel compounds GeCoO and GeNiO which order
antiferromagnetically (at and , ) with different Curie Weiss temperatures (=80.5 K and -15 K),
the usual magnetic frustration criterion is not fulfilled.
Using neutron powder diffraction and magnetization measurements up to 55 T,
both compounds are found with a close magnetic ground state at low temperature
and a similar magnetic behavior (but with a different energy scale), even
though spin anisotropy and first neighbor exchange interactions are quite
different. This magnetic behavior can be understood when considering the main
four magnetic exchange interactions. Frustration mechanisms are then
enlightened.Comment: submitted to Phys.Rev.B (2006
A mid-IR study of Hickson Compact Groups II. Multi-wavelength analysis of the complete GALEX-Spitzer Sample
We present a comprehensive study on the impact of the environment of compact
galaxy groups on the evolution of their members using a multi-wavelength
analysis, from the UV to the infrared, for a sample of 32 Hickson compact
groups (HCGs) containing 135 galaxies. Fitting the SEDs of all galaxies with
the state-of-the-art model of da Cunha (2008) we can accurately calculate their
mass, SFR, and extinction, as well as estimate their infrared luminosity and
dust content. We compare our findings with samples of field galaxies,
early-stage interacting pairs, and cluster galaxies with similar data. We find
that classifying the groups as dynamically "old" or "young", depending on
whether or not at least one quarter of their members are early-type systems, is
physical and consistent with past classifications of HCGs based on their atomic
gas content. [...ABRIDGED...] We also examine their SF properties, UV-optical
and mid-IR colors, and we conclude that all the evidence point to an
evolutionary scenario in which the effects of the group environment and the
properties of the galaxy members are not instantaneous. Early on, the influence
of close companions to group galaxies is similar to the one of galaxy pairs in
the field. However, as the time progresses, the effects of tidal torques and
minor merging, shape the morphology and star formation history of the group
galaxies, leading to an increase of the fraction of early-type members and a
rapid built up of the stellar mass in the remaining late-type galaxies.Comment: Accepted for publication in A&A. Figure resolution degraded for arXiv
limits, full resolution paper available at
http://www.physics.uoc.gr/~bitsakis/paperII_bitsakis.pd
High velocity blue-shifted FeII absorption in the dwarf star-forming galaxy PHL293B: Evidence for a wind driven supershell?
X-shooter and ISIS WHT spectra of the starforming galaxy PHL 293B also known
as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper.
We find broad (FWHM = 1000km/s) and very broad (FWZI = 4000km/s) components
in the Balmer lines, narrow absorption components in the Balmer series
blueshifted by 800km/s, previously undetected FeII multiplet (42) absorptions
also blueshifted by 800km/s, IR CaII triplet stellar absorptions consistent
with [Fe/H] < -2.0 and no broad components or blushifted absorptions in the HeI
lines. Based on historical records, we found no optical variability at the 5
sigma level of 0.02 mag between 2005 and 2013 and no optical variability at the
level of 0.1mag for the past 24 years.
The lack of variability rules out transient phenomena like luminous blue
variables or SN IIn as the origin of the blue shifted absorptions of HI and
FeII. The evidence points to either a young and dense expanding supershell or a
stationary cooling wind, in both cases driven by the young cluster wind.Comment: Accepted for publication in MNRAS; 15 pages, 10 figure
A note on a gauge-gravity relation and functional determinants
We present a refinement of a recently found gauge-gravity relation between
one-loop effective actions: on the gauge side, for a massive charged scalar in
2d dimensions in a constant maximally symmetric electromagnetic field; on the
gravity side, for a massive spinor in d-dimensional (Euclidean) anti-de Sitter
space. The inclusion of the dimensionally regularized volume of AdS leads to
complete mapping within dimensional regularization. In even-dimensional AdS, we
get a small correction to the original proposal; whereas in odd-dimensional
AdS, the mapping is totally new and subtle, with the `holographic trace
anomaly' playing a crucial role.Comment: 6 pages, io
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