1,039 research outputs found
Signatures of Dark Matter Scattering Inelastically Off Nuclei
Direct dark matter detection focuses on elastic scattering of dark matter
particles off nuclei. In this study, we explore inelastic scattering where the
nucleus is excited to a low-lying state of 10-100 keV, with subsequent prompt
de-excitation. We calculate the inelastic structure factors for the odd-mass
xenon isotopes based on state-of-the-art large-scale shell-model calculations
with chiral effective field theory WIMP-nucleon currents. For these cases, we
find that the inelastic channel is comparable to or can dominate the elastic
channel for momentum transfers around 150 MeV. We calculate the inelastic
recoil spectra in the standard halo model, compare these to the elastic case,
and discuss the expected signatures in a xenon detector, along with
implications for existing and future experiments. The combined information from
elastic and inelastic scattering will allow to determine the dominant
interaction channel within one experiment. In addition, the two channels probe
different regions of the dark matter velocity distribution and can provide
insight into the dark halo structure. The allowed recoil energy domain and the
recoil energy at which the integrated inelastic rates start to dominate the
elastic channel depend on the mass of the dark matter particle, thus providing
a potential handle to constrain its mass.Comment: 9 pages, 7 figures. Matches resubmitted version to Phys. Rev. D. One
figure added; supplemental material (fits to the structure functions) added
as an Appendi
The Lopsidedness of Present-Day Galaxies: Results from the Sloan Digital Sky Survey
Large-scale asymmetries in the stellar mass distribution in galaxies are
believed to trace non-equilibrium situations in the luminous and/or dark matter
component. These may arise in the aftermath of events like mergers, accretion,
and tidal interactions. These events are key in the evolution of galaxies. In
this paper we quantify the large-scale lopsidedness of light distributions in
25155 galaxies at z < 0.06 from the Sloan Digital Sky Survey Data Release 4
using the m = 1 azimuthal Fourier mode. We show that the lopsided distribution
of light is primarily due to a corresponding lopsidedness in the stellar mass
distribution. Observational effects, such as seeing, Poisson noise, and
inclination, introduce only small errors in lopsidedness for the majority of
this sample. We find that lopsidedness correlates strongly with other basic
galaxy structural parameters: galaxies with low concentration, stellar mass,
and stellar surface mass density tend to be lopsided, while galaxies with high
concentration, mass, and density are not. We find that the strongest and most
fundamental relationship between lopsidedness and the other structural
parameters is with the surface mass density. We also find, in agreement with
previous studies, that lopsidedness tends to increase with radius. Both these
results may be understood as a consequence of several factors. The outer
regions of galaxies and low-density galaxies are more susceptible to tidal
perturbations, and they also have longer dynamical times (so lopsidedness will
last longer). They are also more likely to be affected by any underlying
asymmetries in the dark matter halo.Comment: 42 pages, 13 figures, 3 tables, accepted to Ap
Radio spectra and polarisation properties of radio-loud Broad Absorption Line Quasars
We present multi-frequency observations of a sample of 15 radio-emitting
Broad Absorption Line Quasars (BAL QSOs), covering a spectral range between 74
MHz and 43 GHz. They display mostly convex radio spectra which typically peak
at about 1-5 GHz (in the observer's rest-frame), flatten at MHz frequencies,
probably due to synchrotron self-absorption, and become steeper at high
frequencies, i.e., >~ 20 GHz. VLA 22-GHz maps (HPBW ~ 80 mas) show unresolved
or very compact sources, with linear projected sizes of <= 1 kpc. About 2/3 of
the sample look unpolarised or weakly polarised at 8.4 GHz, frequency in which
reasonable upper limits could be obtained for polarised intensity. Statistical
comparisons have been made between the spectral index distributions of samples
of BAL and non-BAL QSOs, both in the observed and the rest-frame, finding
steeper spectra among non-BAL QSOs. However constraining this comparison to
compact sources results in no significant differences between both
distributions. This comparison is consistent with BAL QSOs not being oriented
along a particular line of sight. In addition, our analysis of the spectral
shape, variability and polarisation properties shows that radio BAL QSOs share
several properties common to young radio sources like Compact Steep Spectrum
(CSS) or Gigahertz-Peaked Spectrum (GPS) sources.Comment: 18 pages, 11 Postscript figures, 12 Tables. Accepted for publication
in MNRA
Вплив екологічного стану Донецького регіону на його демографічний розвиток
В статті розглянуто важливу проблему впливу забрудненості навколишнього природного середовища на
захворюваність та смертність в регіоні.
Визначено кореляційну залежність між обсягом
викидів забруднюючих речовин та окремими видами
захворюваності, а також ступінь їх впливу, побудовано
функції, що описують їх.В статье рассмотрена важная проблема влияния
загрязненности окружающей естественной среды на
заболеваемость и смертность в регионе.
Определена корреляционная зависимость между
объемом выбросов загрязняющих веществ и отдельными видами заболеваемости, а также степень их влияния,
построены функции, которые описывают их.In the article the important problem of influence of
muddiness of natural environment is considered on morbidity
and death rate in a region.
Certainly cross-correlation dependence between the
volume of extrass of contaminents and separate types of
morbidity, and also degree of their influence, functions which
describe them are built.
Keywords: environment
Tissue inhibitor of metalloproteinases-3 mediates the death of immature oligodendrocytes via TNF-α/TACE in focal cerebral ischemia in mice
Abstract Background and Purpose Oligodendrocyte (OL) death is important in focal cerebral ischemia. TIMP-3 promotes apoptosis in ischemic neurons by inhibiting proteolysis of TNF-α superfamily of death receptors. Since OLs undergo apoptosis during ischemia, we hypothesized that TIMP-3 contributes to OL death. Methods Middle cerebral artery occlusion (MCAO) was induced in Timp-3 knockout (KO) and wild type (WT) mice with 24 or 72 h of reperfusion. Cell death in white matter was investigated by stereology and TUNEL. Mature or immature OLs were identified using antibodies against glutathione S-transferase-π (GST-π) and galactocerebroside (GalC), respectively. Expression and level of proteins were examined using immunohistochemistry and immunoblotting. Protein activities were determined using a FRET peptide. Results Loss of OL-like cells was detected at 72 h only in WT ischemic white matter where TUNEL showed greater cell death. TIMP-3 expression was increased in WT reactive astrocytes. GST-π was reduced in ischemic white matter of WT mice compared with WT shams with no difference between KO and WT at 72 h. GalC level was significantly increased in both KO and WT ischemic white matter at 72 h. However, the increase in GalC in KO mice was significantly higher than WT; most TUNEL-positive cells in ischemic white matter expressed GalC, suggesting TIMP-3 deficiency protects the immature OLs from apoptosis. There were significantly higher levels of cleaved caspase-3 at 72 h in WT white matter than in KO. Greater expression of MMP-3 and -9 was seen in reactive astrocytes and/or microglia/macrophages in WT at 72 h. We found more microglia/macrophages in WT than in KO, which were the predominant source of increased TNF-α detected in the ischemic white matter. TACE activity was significantly increased in ischemic WT white matter, which was expressed in active microglia/macrophages and OLs. Conclusions Our results suggested that focal ischemia leads to proliferation of immature OLs in white matter and that TIMP-3 contributes to a caspase-3-dependent immature OL death via TNF-α-mediated neuroinflammation. Future studies will be needed to delineate the role of MMP-3 and MMP-9 that were increased in the Timp-3 wild type
Fruit crops 1990: a summary of research
Orchard temperature profiles in spring frost conditions / R. D. Brazee, R. D. Fox and D. C. Ferree -- Orchard sprayers: how much spray moves out of the orchard? / R. D. Fox, D. L. Reichard, R. D. Brazee, and F. R. Hall -- Influence of pruning treatments on mature spur-bound 'Starkrimson Delicious' apple trees / D. C. Ferree, J. C. Schmid, J. R. Schupp and I. J. Warrington -- The winter of 1983-84: a test winter for Ohio's fruit crops / C. K. Chandler and D. C. Ferree -- Performance of apple roostock, cultivars and cultural treatments under the stress of the 1988 drought / D. C. Ferree and J. C. Schmid -- Performance of a spur and standard Delicious strain in a slender spindle system / D. C. Ferree and J. C. Schmid -- Survey of Ohio strawberry growers: present practice and future directions / J. C. Scheerens and G. L. Brenneman -- Orchard crop loss assessments: a precondition for improved crop protection decisions / F. R. Hall -- Evaluation of compounds for control of foliar grape phylloxera, Daktulosphaira vitifoliae (Fitch) in Ohio / M. J. McLeod and R. N. Williams -- Marketing Ohio Strawberries / W. T. Rhodus and R. C. Fun
Search for Event Rate Modulation in XENON100 Electronic Recoil Data
We have searched for periodic variations of the electronic recoil event rate
in the (2-6) keV energy range recorded between February 2011 and March 2012
with the XENON100 detector, adding up to 224.6 live days in total. Following a
detailed study to establish the stability of the detector and its background
contributions during this run, we performed an un-binned profile likelihood
analysis to identify any periodicity up to 500 days. We find a global
significance of less than 1 sigma for all periods suggesting no statistically
significant modulation in the data. While the local significance for an annual
modulation is 2.8 sigma, the analysis of a multiple-scatter control sample and
the phase of the modulation disfavor a dark matter interpretation. The
DAMA/LIBRA annual modulation interpreted as a dark matter signature with
axial-vector coupling of WIMPs to electrons is excluded at 4.8 sigma.Comment: 6 pages, 4 figure
Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment
The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410
has been developed by Hamamatsu for dark matter direct detection experiments
using liquid xenon as the target material. We present the results from the
joint effort between the XENON collaboration and the Hamamatsu company to
produce a highly radio-pure photosensor (version R11410-21) for the XENON1T
dark matter experiment. After introducing the photosensor and its components,
we show the methods and results of the radioactive contamination measurements
of the individual materials employed in the photomultiplier production. We then
discuss the adopted strategies to reduce the radioactivity of the various PMT
versions. Finally, we detail the results from screening 216 tubes with
ultra-low background germanium detectors, as well as their implications for the
expected electronic and nuclear recoil background of the XENON1T experiment.Comment: 10 pages, 5 figure
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