82 research outputs found
Microwave conductivity in polycrystalline (BEDT-TTF)2I3 material
Polycrystalline material of the α-phase of (BEDT-TTF)2I3 was compressed to small samples (4-mm x 1mm, thickness 0.3 mm typically) at a pressure of 10 kbar. Annealing at 70°C yields the superconducting αt-phase. Microwaves (10,2 GHz) enable the measurements of the conductivity for stepwise annealing after every annealing step in always the same sample. For annealing times 10 min all conductivity versus temperature curves are intersecting in an isosbestlc point at 190 K. This behaviour can be described by a conductivity relation for a two component system, from which was determined the volume fraction of the new grown αt-phase in dependence of the annealing time. Starting annealing (annealing times < 10 min) shows another unexpected phase transformation. After 2 min annealing the conductivity at 200 K increases by more than one order of magnitude, but then decreases of further annealing (5-10 min) down to the value for the unannealed sample
Cerebrospinal fluid findings in patients with neurological manifestations in post-COVID-19 syndrome
BACKGROUND: Information on cerebrospinal fluid (CSF) findings in patients with neurological manifestations in post-COVID-19 syndrome is scarce. METHODS: Retrospective evaluation of 84 CSF samples in patients fulfilling post-COVID-19 criteria in two neurological post-COVID-19 outpatient clinics. RESULTS: In 68% of samples, all CSF parameters were normal. The most frequent pathological CSF finding was elevation of total protein (median total protein 33.3 mg/dl [total range 18.5-116.2]) in 20 of 83 (24%) samples. The second most prevalent pathological finding was a blood-CSF barrier dysfunction as measured by elevation of QAlb (median QAlb 4.65 [2.4-13.2]) in 11/84 (13%). Pleocytosis was found in only 5/84 (6%) samples and was mild in all of them. CSF-restricted oligoclonal bands were found in 5/83 (6%) samples. Anti-neuronal autoantibodies in CSF were negative in most cases, whilst 12/68 (18%) samples were positive for anti-myelin autoantibodies in serum. PCR for herpesviridae (HSV-1/-2, VZV, EBV, CMV, HHV6) showed, if at all, only weakly positive results in CSF or EDTA whole blood/plasma. CONCLUSIONS: The majority of samples did not show any pathologies. The most frequent findings were elevation of total protein and blood-CSF barrier dysfunction with no signs of intrathecal inflammation. CSF analysis still keeps its value for exclusion of differential diagnoses
Femtosecond Coherence and Quantum Control of Single Molecules at Room Temperature
Quantum mechanical phenomena, such as electronic coherence and entanglement,
play a key role in achieving the unrivalled efficiencies of light-energy
conversion in natural photosynthetic light-harvesting complexes, and triggered
the growing interest in the possibility of organic quantum computing. Since
biological systems are intrinsically heterogeneous, clear relations between
structural and quantum-mechanical properties can only be obtained by
investigating individual assemblies. However, single-molecule techniques to
access ultrafast coherences at physiological conditions were not available so
far. Here we show by employing femtosecond pulse-shaping techniques that
quantum coherences in single organic molecules can be created, probed, and
manipulated at ambient conditions even in highly disordered solid environments.
We find broadly distributed coherence decay times for different individual
molecules giving direct insight into the structural heterogeneity of the local
surroundings. Most importantly, we induce Rabi-oscillations and control the
coherent superposition state in a single molecule, thus performing a basic
femtosecond single-qubit operation at room temperature
Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes
Structure and Formation of Elliptical and Spheroidal Galaxies
New surface photometry of all known elliptical galaxies in the Virgo cluster
is added to published data to derive composite profiles over large dynamic
ranges. Sersic functions fit them remarkably well. Effective brightnesses and
radii are derived via Sersic fits and by integrating the profiles
nonparametrically. We strongly confirm two dichotomies: (1) Elliptical galaxies
from cDs to M32 form a tight sequence in Fundamental Plane parameter space that
is almost perpendicular to the sequence of spheroidal galaxies from NGC 205 to
Draco. This is consistent with our understanding of their different formation
processes: mergers for Es and conversion of late-type galaxies into spheroidals
by environmental effects and by energy feedback from supernovae. (2)
Ellipticals come in two varieties: e.g., our 10 brightest Es have cuspy cores;
our 17 fainter Es do not have cores. We find a new distinct component in
coreless Es. All have extra light at the center above the inward extrapolation
of the outer Sersic profile. We suggest that extra light is made by starbursts
in dissipational (wet) mergers, as in numerical simulations. Three other new
aspects also point to an explanation of how the E-E dichotomy formed: extra
light Es were made in wet mergers while core Es were made in dry mergers. We
confirm that core Es do and extra light Es generally do not contain X-ray gas.
This suggests why the E-E dichotomy arose. Only core Es and their progenitors
are massive enough to retain hot gas that can make dry mergers dry and protect
old star populations from late star formation.Comment: 94 pages, 77 figures from 170 Postscript files; requires
emulateapj.sty, apjfonts.sty, and psfig.sty; accepted for publication in
ApJS; for a version with full resolution figures, see
http://chandra.as.utexas.edu/~kormendy/kfcb.htm
Dark Matter in the Milky Way's Dwarf Spheroidal Satellites
The Milky Way's dwarf spheroidal satellites include the nearest, smallest and
least luminous galaxies known. They also exhibit the largest discrepancies
between dynamical and luminous masses. This article reviews the development of
empirical constraints on the structure and kinematics of dSph stellar
populations and discusses how this phenomenology translates into constraints on
the amount and distribution of dark matter within dSphs. Some implications for
cosmology and the particle nature of dark matter are discussed, and some
topics/questions for future study are identified.Comment: A version with full-resolution figures is available at
http://www.cfa.harvard.edu/~mwalker/mwdsph_review.pdf; 70 pages, 22 figures;
invited review article to be published in Vol. 5 of the book "Planets, Stars,
and Stellar Systems", published by Springe
Identification of regulatory variants associated with genetic susceptibility to meningococcal disease.
Non-coding genetic variants play an important role in driving susceptibility to complex diseases but their characterization remains challenging. Here, we employed a novel approach to interrogate the genetic risk of such polymorphisms in a more systematic way by targeting specific regulatory regions relevant for the phenotype studied. We applied this method to meningococcal disease susceptibility, using the DNA binding pattern of RELA - a NF-kB subunit, master regulator of the response to infection - under bacterial stimuli in nasopharyngeal epithelial cells. We designed a custom panel to cover these RELA binding sites and used it for targeted sequencing in cases and controls. Variant calling and association analysis were performed followed by validation of candidate polymorphisms by genotyping in three independent cohorts. We identified two new polymorphisms, rs4823231 and rs11913168, showing signs of association with meningococcal disease susceptibility. In addition, using our genomic data as well as publicly available resources, we found evidences for these SNPs to have potential regulatory effects on ATXN10 and LIF genes respectively. The variants and related candidate genes are relevant for infectious diseases and may have important contribution for meningococcal disease pathology. Finally, we described a novel genetic association approach that could be applied to other phenotypes
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