3,177 research outputs found
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Dynamic MAIT cell response with progressively enhanced innateness during acute HIV-1 infection.
Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre- and post-infection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality
Sonoluminescing air bubbles rectify argon
The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the
percentage of inert gas within the bubble. We propose a theory for this
dependence, based on a combination of principles from sonochemistry and
hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent
reaction to water soluble gases implies that strongly forced air bubbles
eventually consist of pure argon. Thus it is the partial argon (or any other
inert gas) pressure which is relevant for stability. The theory provides
quantitative explanations for many aspects of SBSL.Comment: 4 page
A New Method to Estimate the Noise in Financial Correlation Matrices
Financial correlation matrices measure the unsystematic correlations between
stocks. Such information is important for risk management. The correlation
matrices are known to be ``noise dressed''. We develop a new and alternative
method to estimate this noise. To this end, we simulate certain time series and
random matrices which can model financial correlations. With our approach,
different correlation structures buried under this noise can be detected.
Moreover, we introduce a measure for the relation between noise and
correlations. Our method is based on a power mapping which efficiently
suppresses the noise. Neither further data processing nor additional input is
needed.Comment: 25 pages, 8 figure
Trends in alcohol use among Hawai‘i adolescents
It is important to review trends in youth alcohol use over time in order to effectively tailor prevention programs to address those trends. This article reviews data on alcohol use behaviors from the Centers for Disease Control and Prevention\u27s Youth Risk Behavior Survey in Hawai‘i from 1993 to 2007. Five alcohol use indicators were examined and stratified by grade level, from 9th grade through 12th grade. Significant drops in nearly all indicators are seen among 9th through 11th graders, but not among 12th graders. This suggests that Hawai‘i youth are responding well to anti-alcohol messaging as young teens, but a different approach may be needed to target older teens
Genome-wide association studies identify multiple genetic loci influencing eyebrow color variation in Europeans
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Redox Bias in Loss on Ignition Moisture Measurement for Relatively Pure Plutonium-Bearing Oxide Materials
This paper evaluates potential analytical bias in application of the Loss on Ignition (LOI) technique for moisture measurement to relatively pure (plutonium assay of 80 wt.% or higher) oxides containing uranium that have been stabilized according to stabilization and storage standard DOE-STD-3013-2000 (STD- 3013). An immediate application is to Rocky Flats (RF) materials derived from high-grade metal hydriding separations subsequently treated by multiple calcination cycles. Specifically evaluated are weight changes due to oxidation/reduction of multivalent impurity oxides that could mask true moisture equivalent content measurement. Process knowledge and characterization of materials representing complex-wide materials to be stabilized and packaged according to STD-3013, and particularly for the immediate RF target stream, indicate that oxides of uranium, iron and gallium are the only potential multivalent constituents expected to be present above 0.5 wt.%. The evaluation show s that of these constituents, with few exceptions, only uranium oxides can be present at a sufficient level to produce weight gain biases significant with respect to the LOI stability test. In general, these formerly high-value, high-actinide content materials are reliably identifiable by process knowledge and measurement. Significant bias also requires that UO2 components remain largely unoxidized after calcination and are largely converted to U3O8 during LOI testing at only slightly higher temperatures. Based on well-established literature, it is judged unlikely that this set of conditions will be realized in practice. We conclude that it is very likely that LOI weight gain bias will be small for the immediate target RF oxide materials containing greater than 80 wt.% plutonium plus a much smaller uranium content. Recommended tests are in progress to confirm these expectations and to provide a more authoritative basis for bounding LOI oxidation/reduction biases. LOI bias evaluation is more difficult for lower purity materials and for fuel-type uranium-plutonium oxides. However, even in these cases testing may show that bias effects are manageable
RPA for Light-Front Hamiltonian Field Theory
A self-consistent random phase approximation (RPA) is proposed as an
effective Hamiltonian method in Light-Front Field Theory (LFFT). We apply the
general idea to the light-front massive Schwinger model to obtain a new bound
state equation and solve it numerically.Comment: A major revision in presentation, while the results essentially
unchanged. 2 figs. replaced, 1 fig. added, some parts of Sec. V moved to Sec.
IV, some wording changed, typos correcte
Zero Mode and Symmetry Breaking on the Light Front
We study the zero mode and the spontaneous symmetry breaking on the light
front (LF). We use the discretized light-cone quantization (DLCQ) of
Maskawa-Yamawaki to treat the zero mode in a clean separation from all other
modes. It is then shown that the Nambu-Goldstone (NG) phase can be realized on
the trivial LF vacuum only when an explicit symmetry-breaking mass of the NG
boson is introduced. The NG-boson zero mode integrated over the LF
must exhibit singular behavior in the symmetric limit
, which implies that current conservation is violated at zero
mode, or equivalently the LF charge is not conserved even in the symmetric
limit. We demonstrate this peculiarity in a concrete model, the linear sigma
model, where the role of zero-mode constraint is clarified. We further compare
our result with the continuum theory. It is shown that in the continuum theory
it is difficult to remove the zero mode which is not a single mode with measure
zero but the accumulating point causing uncontrollable infrared singularity. A
possible way out within the continuum theory is also suggested based on the
`` theory''. We finally discuss another problem of the zero mode in the
continuum theory, i.e., no-go theorem of Nakanishi-Yamawaki on the
non-existence of LF quantum field theory within the framework of Wightman
axioms, which remains to be a challenge for DLCQ, `` theory'' or any other
framework of LF theory.Comment: 60 pages, the final section has been expanded. A few minor
corrections; version to be published in Phys. Rev.
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