1,638 research outputs found
The supercuspidal representations of p-adic classical groups
Let G be a unitary, symplectic or special orthogonal group over a locally
compact non-archimedean local field of odd residual characteristic. We
construct many new supercuspidal representations of G, and Bushnell-Kutzko
types for these representations. Moreover, we prove that every irreducible
supercuspidal representation of G arises from our constructions.Comment: 55 pages -- minor changes from 1st version (mostly in sections 2.2,
4.2 and 6.2). To appear in Inventiones mathematicae, 2008 (DOI is not yet
active as at 12 Nov 2007
Resistance of CCA and Boron-Treated Rubberwood Composites Against Termites, Coptotermes curvignathus Holmgren
A study was conducted to evaluate the resistance of copper-chromium-arsenic
(CCA)-and boron-treated rubberwood composites against subterranean termite,
Coptotermes curvignathus Holmgren. The materials tested were phenol
formaldehyde (PF)-bonded oriented strand board (OSB), melamine urea
formaldehyde (MUF)-bonded particleboard and urea formaldehyde (UF)bonded
laminated veneer lumber (LVL). Solutions of CCA (0.5-4.0%, w/w of
oven dry weight of particles) and boron compounds (boric acid equivalent (BAE) , 0.5 - 1.5% w/w) were separately sprayed onto the furnish during
boards manufacturing. The untreated LVL, some of the OSB and particleboard
were served as control for comparing purposes. Test blocks, 25 mm x 25 mm
x 12 mm were cut from each of the composites and were exposed to 1± 0.05 g
termites (10% soldiers and 90% workers) in test bottles for 28 days (ASTM D:
3345-92). Weight losses of the blocks and termite mortality were calculated.
OSB treated with 2.0% eGA had the lowest weight loss value (3.0%) compared
to those treated with other concentrations (weight loss values = 4.1-6.8%) and
those untreated (18.4%). The weight loss for 1.0% and 1.5% BAE-treated OSB
blocks were 6.9% and 3.8%, respectively. The resistance of particleboards
against termite attack increased by 77% when they were treated with 1% BAE.
The mean weight loss value for these boards was 6.13%. Among the untreated
rubberwood composites, PF-bonded OSB had the highest resistance against
termite attack. UF-bonded LVL was significantly more resistant to termite
attack than MUF-bonded particle boards. The weight loss value for the former
was 19.3% and the latter was 26.3%. At the end of the test periods, the
mortality of termites that were placed together with the treated blocks was
100%, whereas for those placed together with the untreated composites and
solid rubberwood, the mortality ranged from 0-16%
The steady state quantum statistics of a non-Markovian atom laser
We present a fully quantum mechanical treatment of a single-mode atomic
cavity with a pumping mechanism and an output coupling to a continuum of
external modes. This system is a schematic description of an atom laser. In the
dilute limit where atom-atom interactions are negligible, we have been able to
solve this model without making the Born and Markov approximations. When
coupling into free space, it is shown that for reasonable parameters there is a
bound state which does not disperse, which means that there is no steady state.
This bound state does not exist when gravity is included, and in that case the
system reaches a steady state. We develop equations of motion for the two-time
correlation in the presence of pumping and gravity in the output modes. We then
calculate the steady-state output energy flux from the laser.Comment: 14 pages (twocloumn), 6 figure
Electrostatics of ions inside the nanopores and trans-membrane channels
A model of a finite cylindrical ion channel through a phospholipid membrane
of width separating two electrolyte reservoirs is studied. Analytical
solution of the Poisson equation is obtained for an arbitrary distribution of
ions inside the trans-membrane pore. The solution is asymptotically exact in
the limit of large ionic strength of electrolyte on the two sides of membrane.
However, even for physiological concentrations of electrolyte, the
electrostatic barrier sizes found using the theory are in excellent agreement
with the numerical solution of the Poisson equation. The analytical solution is
used to calculate the electrostatic potential energy profiles for pores
containing charged protein residues. Availability of a semi-exact interionic
potential should greatly facilitate the study of ionic transport through
nanopores and ion channels
Structural basis of severe acute respiratory syndrome coronavirus ADP-ribose-1''-phosphate dephosphorylation by a conserved domain of nsP3.
The crystal structure of a conserved domain of nonstructural protein 3 (nsP3) from severe acute respiratory syndrome coronavirus (SARS-CoV) has been solved by single-wavelength anomalous dispersion to 1.4 A resolution. The structure of this "X" domain, seen in many single-stranded RNA viruses, reveals a three-layered alpha/beta/alpha core with a macro-H2A-like fold. The putative active site is a solvent-exposed cleft that is conserved in its three structural homologs, yeast Ymx7, Archeoglobus fulgidus AF1521, and Er58 from E. coli. Its sequence is similar to yeast YBR022W (also known as Poa1P), a known phosphatase that acts on ADP-ribose-1''-phosphate (Appr-1''-p). The SARS nsP3 domain readily removes the 1'' phosphate group from Appr-1''-p in in vitro assays, confirming its phosphatase activity. Sequence and structure comparison of all known macro-H2A domains combined with available functional data suggests that proteins of this superfamily form an emerging group of nucleotide phosphatases that dephosphorylate Appr-1''-p
A biophysical Raman spectroscopic model for noninvasive screening of skin cancer
Raman spectroscopy (RS) is sensitive to the molecular composition of biological tissues. Raman optical fiber- based probes have demonstrated efficacy in noninvasive cancer screening of the skin, breast, stomach, cervical, lung and brain. Currently, statistical algorithms such as principle component analysis (PCA) are the standard approaches for describing the spectral variance of the RS data and providing tissue classification. However, a PCA-based analysis does not allow for an examination of the biophysical basis of disease, such as microstructural organization of proteins and lipids. Understanding those biophysical parameters is essential to interpret the diagnostic result similar to that a pathologist is familiar reading, and develop diagnostic algorithms for fast and accurate cancer screening.
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Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory
During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo. Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9−/− adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9−/− mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors
ESO Imaging Survey: infrared observations of CDF-S and HDF-S
This paper presents infrared data obtained from observations carried out at
the ESO 3.5m New Technology Telescope (NTT) of the Hubble Deep Field South
(HDF-S) and the Chandra Deep Field South (CDF-S). These data were taken as part
of the ESO Imaging Survey (EIS) program, a public survey conducted by ESO to
promote follow-up observations with the VLT. In the HDF-S field the infrared
observations cover an area of ~53 square arcmin, encompassing the HST WFPC2 and
STIS fields, in the JHKs passbands. The seeing measured in the final stacked
images ranges from 0.79" to 1.22" and the median limiting magnitudes (AB
system, 2" aperture, 5sigma detection limit) are J_AB~23.0, H_AB~22.8 and
K_AB~23.0 mag. Less complete data are also available in JKs for the adjacent
HST NICMOS field. For CDF-S, the infrared observations cover a total area of
\~100 square arcmin, reaching median limiting magnitudes (as defined above) of
J_AB~23.6 and K_AB~22.7 mag. For one CDF-S field H-band data are also
available. This paper describes the observations and presents the results of
new reductions carried out entirely through the un-supervised, high-throughput
EIS Data Reduction System and its associated EIS/MVM C++-based image processing
library developed, over the past 5 years, by the EIS project and now publicly
available. The paper also presents source catalogs extracted from the final
co-added images which are used to evaluate the scientific quality of the survey
products, and hence the performance of the software. This is done comparing the
results obtained in the present work with those obtained by other authors from
independent data and/or reductions carried out with different software packages
and techniques. The final science-grade catalogs and co-added images are
available at CDS.Comment: Accepted for publication in A&A, 13 pages, 12 figures; a full
resolution version of the paper is available from
http://www.astro.ku.dk/~lisbeth/eisdata/papers/4528.pdf ; related catalogs
and images are available through http://www.astro.ku.dk/~lisbeth/eisdata
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A 2000-year annual record of snow accumulation rates for Law Dome, East Antarctica
Accurate high-resolution records of snow accumulation rates in Antarctica are crucial for estimating ice sheet mass balance and subsequent sea level change. Snowfall rates at Law Dome, East Antarctica, have been linked with regional atmospheric circulation to the mid-latitudes as well as regional Antarctic snowfall. Here, we extend the length of the Law Dome accumulation record from 750 years to 2035 years, using recent annual layer dating that extends to 22 BCE. Accumulation rates were calculated as the ratio of measured to modelled layer thicknesses, multiplied by the long-term mean accumulation rate. The modelled layer thicknesses were based on a power-law vertical strain rate profile fitted to observed annual layer thickness. The periods 380–442, 727–783 and 1970–2009 CE have above-average snow accumulation rates, while 663–704, 933–975 and 1429–1468 CE were below average, and decadal-scale snow accumulation anomalies were found to be relatively common (74 events in the 2035-year record). The calculated snow accumulation rates show good correlation with atmospheric reanalysis estimates, and significant spatial correlation over a wide expanse of East Antarctica, demonstrating that the Law Dome record captures larger-scale variability across a large region of East Antarctica well beyond the immediate vicinity of the Law Dome summit. Spectral analysis reveals periodicities in the snow accumulation record which may be related to El Niño–Southern Oscillation (ENSO) and Interdecadal Pacific Oscillation (IPO) frequencies
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