1,158 research outputs found
A distinct plasmablast and naive B-cell phenotype in primary immune thrombocytopenia
Obtained from the Haematologica Journal website http://www.haematologica.org/content/101/6/698.full.pdf+html
Material published in Haematologica is covered by copyright. All rights reserved to Ferrata
Storti Foundation. Copies of articles are allowed for personal or internal use. A permission
in writing by the publisher is requested for any other use.Primary funding for this study was from GSK. SMF was
funded by a Translational Medicine and Therapeutics PhD studentship
jointly funded by the Wellcome Trust and GSK. The
UK ITP Registry (www.ukitpregistry.com) is supported through
unrestricted educational grants from GSK and Amgen
Ultrahard carbon film from epitaxial two-layer graphene
Atomically thin graphene exhibits fascinating mechanical properties, although
its hardness and transverse stiffness are inferior to those of diamond. To
date, there hasn't been any practical demonstration of the transformation of
multi-layer graphene into diamond-like ultra-hard structures. Here we show that
at room temperature and after nano-indentation, two-layer graphene on SiC(0001)
exhibits a transverse stiffness and hardness comparable to diamond, resisting
to perforation with a diamond indenter, and showing a reversible drop in
electrical conductivity upon indentation. Density functional theory
calculations suggest that upon compression, the two-layer graphene film
transforms into a diamond-like film, producing both elastic deformations and
sp2-to-sp3 chemical changes. Experiments and calculations show that this
reversible phase change is not observed for a single buffer layer on SiC or
graphene films thicker than 3 to 5 layers. Indeed, calculations show that
whereas in two-layer graphene layer-stacking configuration controls the
conformation of the diamond-like film, in a multilayer film it hinders the
phase transformation.Comment: Published online on Nature Nanotechnology on December 18, 201
Theory of Star Formation
We review current understanding of star formation, outlining an overall
theoretical framework and the observations that motivate it. A conception of
star formation has emerged in which turbulence plays a dual role, both creating
overdensities to initiate gravitational contraction or collapse, and countering
the effects of gravity in these overdense regions. The key dynamical processes
involved in star formation -- turbulence, magnetic fields, and self-gravity --
are highly nonlinear and multidimensional. Physical arguments are used to
identify and explain the features and scalings involved in star formation, and
results from numerical simulations are used to quantify these effects. We
divide star formation into large-scale and small-scale regimes and review each
in turn. Large scales range from galaxies to giant molecular clouds (GMCs) and
their substructures. Important problems include how GMCs form and evolve, what
determines the star formation rate (SFR), and what determines the initial mass
function (IMF). Small scales range from dense cores to the protostellar systems
they beget. We discuss formation of both low- and high-mass stars, including
ongoing accretion. The development of winds and outflows is increasingly well
understood, as are the mechanisms governing angular momentum transport in
disks. Although outstanding questions remain, the framework is now in place to
build a comprehensive theory of star formation that will be tested by the next
generation of telescopes.Comment: 120 pages, to appear in ARAA. No changes from v1 text; permission
statement adde
Very Cold Gas and Dark Matter
We have recently proposed a new candidate for baryonic dark matter: very cold
molecular gas, in near-isothermal equilibrium with the cosmic background
radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed
in a fractal structure, resembling the hierarchical structure of the detected
interstellar medium.
We present some perspectives of detecting this very cold gas, either directly
or indirectly. The H molecule has an "ultrafine" structure, due to the
interaction between the rotation-induced magnetic moment and the nuclear spins.
But the lines fall in the km domain, and are very weak. The best opportunity
might be the UV absorption of H in front of quasars. The unexpected cold
dust component, revealed by the COBE/FIRAS submillimetric results, could also
be due to this very cold H gas, through collision-induced radiation, or
solid H grains or snowflakes. The -ray distribution, much more
radially extended than the supernovae at the origin of cosmic rays
acceleration, also points towards and extended gas distribution.Comment: 16 pages, Latex pages, crckapb macro, 3 postscript figures, uuencoded
compressed tar file. To be published in the proceeedings of the
"Dust-Morphology" conference, Johannesburg, 22-26 January, 1996, D. Block
(ed.), (Kluwer Dordrecht
Search for sterile neutrino mixing in the MINOS long-baseline experiment
A search for depletion of the combined flux of active neutrino species over a 735 km baseline is reported using neutral-current interaction data recorded by the MINOS detectors in the NuMI neutrino beam. Such a depletion is not expected according to conventional interpretations of neutrino oscillation data involving the three known neutrino flavors. A depletion would be a signature of oscillations or decay to postulated noninteracting sterile neutrinos, scenarios not ruled out by existing data. From an exposure of 3.18×1020 protons on target in which neutrinos of energies between ~500¿¿MeV and 120 GeV are produced predominantly as ¿µ, the visible energy spectrum of candidate neutral-current reactions in the MINOS far detector is reconstructed. Comparison of this spectrum to that inferred from a similarly selected near-detector sample shows that of the portion of the ¿µ flux observed to disappear in charged-current interaction data, the fraction that could be converting to a sterile state is less than 52% at 90% confidence level (C.L.). The hypothesis that active neutrinos mix with a single sterile neutrino via oscillations is tested by fitting the data to various models. In the particular four-neutrino models considered, the mixing angles ¿24 and ¿34 are constrained to be less than 11° and 56° at 90% C.L., respectively. The possibility that active neutrinos may decay to sterile neutrinos is also investigated. Pure neutrino decay without oscillations is ruled out at 5.4 standard deviations. For the scenario in which active neutrinos decay into sterile states concurrently with neutrino oscillations, a lower limit is established for the neutrino decay lifetime t3/m3>2.1×10-12¿¿s/eV at 90% C.L
Long-term and trans-life-cycle effects of exposure to ocean acidification in the green sea urchin Strongylocentrotus droebachiensis
Anthropogenic CO2 emissions are acidifying the world’s oceans. A growing body of evidence demonstrates that ocean acidification can impact survival, growth, development and physiology of marine invertebrates. Here, we tested the impact of long-term (up to 16 months) and trans-life-cycle (adult, embryo/larvae and juvenile) exposure to elevated pCO2 (1,200 μatm, compared to control 400 μatm) on the green sea urchin Strongylocentrotus droebachiensis. Female fecundity was decreased 4.5-fold when acclimated to elevated pCO2 for 4 months during reproductive conditioning, while no difference was observed in females acclimated for 16 months. Moreover, adult pre-exposure for 4 months to elevated pCO2 had a direct negative impact on subsequent larval settlement success. Five to nine times fewer offspring reached the juvenile stage in cultures using gametes collected from adults previously acclimated to high pCO2 for 4 months. However, no difference in larval survival was observed when adults were pre-exposed for 16 months to elevated pCO2. pCO2 had no direct negative impact on juvenile survival except when both larvae and juveniles were raised in elevated pCO2. These negative effects on settlement success and juvenile survival can be attributed to carry-over effects from adults to larvae and from larvae to juveniles. Our results support the contention that adult sea urchins can acclimate to moderately elevated pCO2 in a matter of a few months and that carry-over effects can exacerbate the negative impact of ocean acidification on larvae and juveniles
Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments
Peer reviewedPublisher PD
Measurement of the multiple-muon charge ratio in the MINOS Far Detector
The charge ratio, Rμ=Nμ+/Nμ−, for cosmogenic multiple-muon events observed at an underground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be Rμ=1.104±0.006(stat)+0.009−0.010(syst). This measurement complements previous determinations of single-muon and multiple-muon charge ratios at underground sites and serves to constrain models of cosmic-ray interactions at TeV energies
Search for Sterile Neutrinos Mixing with Muon Neutrinos in MINOS
We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and 735 km in a νμ-dominated beam with a peak energy of 3 GeV. The data, from an exposure of 10.56 × 10^20 protons on target, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters θ24 and Δm41^2 and set limits on parameters of the four-dimensional Pontecorvo-Maki- Nakagawa-Sakata matrix, |Uμ4|2 and |Uτ4|2, under the assumption that mixing between νe and νs is negligible (|Ue4|^2 = 0). No evidence for νμ → νs transitions is found and we set a world-leading limit on θ24 for values of Δm41^2 ≲ 1 eV^2
Research data supporting "Brain derived neurotrophic factor (BDNF) and secreted amyloid precursor protein-α (sAPPα) response to moderate and high intensity exercise"
The attached data files include the raw data from the paper entitled ‘Brain derived neurotrophic factor (BDNF) and secreted amyloid precursor protein-α (sAPPα) response to moderate and high intensity exercise’. The excel file contains individual data on participant demographics, heart rate and rate of perceived exertion, BDNF levels in serum, plasma, platelet-poor-plasma, and per platelet, and sAPPa levels in serum before and after moderate and high intensity exercise. The word document includes some additional statistical analysis examining the relationship between sample timing, session, and BDNF levels
- …
