1,066 research outputs found
STAR inner tracking upgrade - A performance study
Anisotropic flow measurements have demonstrated development of partonic
collectivity in Au+Au collisions at RHIC. To understand the
partonic EOS, thermalization must be addressed. Collective motion of
heavy-flavor (c,b) quarks can be used to indicate the degree of thermalization
of the light-flavor quarks (u,d,s). Measurement of heavy-flavor quark
collectivity requires direct reconstruction of heavy-flavor hadrons in the low
\pt region. Measurement of open charm spectra to high \pt can be used to
investigate heavy-quark energy loss and medium properties. The Heavy Flavor
Tracker (HFT), a proposed upgrade to the STAR experiment at midrapidity, will
measure of open-charm hadrons to very low \pt by reconstructing their
displaced decay vertices. The innermost part of the HFT is the PIXEL detector
(made of two low mass monolithic active pixel sensor layers), which delivers a
high precision position measurement close to the collision vertex. The
Intermediate Silicon Tracker (IST), a 1-layer strip detector, is essential to
improve hit identification in the PIXEL detector when running at full RHIC-II
luminosity. Using a full GEANT simulation, open charm measurement capabilities
of STAR with the HFT will be shown. Its performance in a broad \pt range will
be demonstrated on (\pt > 0.5\mathrm{GeV}/c) and
(\pt < 10\mathrm{GeV}/c) measurements of \D meson. Results of
reconstruction of \Lc baryon in heavy-ion collisions are presented.Comment: to appear in EPJ C (Hot Quarks 2008 conference volume
Mpox Virus in Pregnancy, the Placenta, and Newborn.
Before its eradication, the smallpox virus was a significant cause of poor obstetric outcomes, including maternal and fetal morbidity and mortality. The mpox (monkeypox) virus is now the most pathogenic member of the Orthopoxvirus genus infecting humans. The 2022 global mpox outbreak has focused attention on its potential effects during pregnancy.
To understand the comparative effects of different poxvirus infections on pregnancy, including mpox virus, variola virus, vaccinia virus, and cowpox virus. The impact on the pregnant individual, fetus, and placenta will be examined, with particular attention to the occurrence of intrauterine vertical transmission and congenital infection.
The data are obtained from the authors' cases and from various published sources, including early historical information and contemporary publications.
Smallpox caused maternal and perinatal death, with numerous cases reported of intrauterine transmission. In endemic African countries, mpox has also affected pregnant individuals, with up to a 75% perinatal case fatality rate. Since the start of the 2022 mpox outbreak, increasing numbers of pregnant women have been infected with the virus. A detailed description is given of the congenital mpox syndrome in a stillborn fetus, resulting from maternal-fetal transmission and placental infection, and the potential mechanisms of intrauterine infection are discussed. Other poxviruses, notably vaccinia virus and, in 1 case, cowpox virus, can also cause perinatal infection. Based on the historical evidence of poxvirus infections, mpox remains a threat to the pregnant population, and it can be expected that additional cases will occur in the future
Atom gratings produced by large angle atom beam splitters
An asymptotic theory of atom scattering by large amplitude periodic
potentials is developed in the Raman-Nath approximation. The atom grating
profile arising after scattering is evaluated in the Fresnel zone for
triangular, sinusoidal, magneto-optical, and bichromatic field potentials. It
is shown that, owing to the scattering in these potentials, two
\QTR{em}{groups} of momentum states are produced rather than two distinct
momentum components. The corresponding spatial density profile is calculated
and found to differ significantly from a pure sinusoid.Comment: 16 pages, 7 figure
Heritability and correlations among learning and inhibitory control traits
To understand the evolution of cognitive abilities, we need to understand both how selection acts upon them and their genetic (co)variance structure. Recent work suggests that there are fitness consequences for free-living individuals with particular cognitive abilities. However, our current understanding of the heritability of these abilities is restricted to domesticated species subjected to artificial selection. We investigated genetic variance for, and genetic correlations among four cognitive abilities: inhibitory control, visual and spatial discrimination, and spatial ability, measured on >450 pheasants, Phasianus colchicus, over four generations. Pheasants were reared in captivity but bred from adults that lived in the wild and hence, were subject to selection on survival. Pheasant chicks are precocial and were reared without parents, enabling us to standardize environmental and parental care effects. We constructed a pedigree based on 15 microsatellite loci and implemented animal models to estimate heritability. We found moderate heritabilities for discrimination learning and inhibitory control (h2 = 0.17–0.23) but heritability for spatial ability was low (h2 = 0.09). Genetic correlations among-traits were largely positive but characterized by high uncertainty and were not statistically significant. Principle component analysis of the genetic correlation matrix estimate revealed a leading component that explained 69% of the variation, broadly in line with expectations under a general intelligence model of cognition. However, this pattern was not apparent in the phenotypic correlation structure which was more consistent with a modular view of animal cognition. Our findings highlight that the expression of cognitive traits is influenced by environmental factors which masks the underlying genetic structure
Magnetic trapping of ultracold neutrons
Three-dimensional magnetic confinement of neutrons is reported. Neutrons are
loaded into an Ioffe-type superconducting magnetic trap through inelastic
scattering of cold neutrons with 4He. Scattered neutrons with sufficiently low
energy and in the appropriate spin state are confined by the magnetic field
until they decay. The electron resulting from neutron decay produces
scintillations in the liquid helium bath that results in a pulse of extreme
ultraviolet light. This light is frequency downconverted to the visible and
detected. Results are presented in which 500 +/- 155 neutrons are magnetically
trapped in each loading cycle, consistent with theoretical predictions. The
lifetime of the observed signal, 660 s +290/-170 s, is consistent with the
neutron beta-decay lifetime.Comment: 17 pages, 18 figures, accepted for publication in Physical Review
Foreword: Control and Conservation of Lampreys Beyond 2020 – Proceedings from the 3rd Sea Lamprey International Symposium (SLIS III)
This special issue summarizes outcomes from the 3rd Sea Lamprey International Symposium (SLIS III; Fig. 1) held 28 July – 2 August 2019 at Wayne State University in Detroit, Michigan, U.S.A. The first two symposia (SLIS I and SLIS II) were held 30 July – 8 August 1979 at Northern Michigan University in Marquette, Michigan and 14–18 August 2000 at Lake Superior State University in Sault Ste. Marie, Michigan, respectively. The published volumes from these symposia in 1980 (Canadian Journal of Fisheries and Aquatic Sciences, Volume 37, Issue 11) and 2003 (Journal of Great Lakes Research Volume 29, Supplement 1) have been invaluable references for the broader scientific community and for management agencies around the Laurentian Great Lakes; cited over 4800 and 3300 times, respectively. SLIS III was attended by over 150 scientists, biologists, resource managers, graduate students, and Commission advisors, including participants from Australia, Canada, China, Japan, New Zealand, Portugal, Spain, the United Kingdom, and the United States (Fig. 2). Similar to SLIS I and SLIS II, the goals of SLIS III were to provide a forum to (i) update and publish information on sea lamprey control and research on lampreys since SLIS II, (ii) exchange knowledge and ideas to bring practitioners to a common plateau of understanding, and (iii) develop innovative initiatives and stimulate new vigor in efforts to control sea lamprey in the Great Lakes and to conserve lampreys in their native ranges. The emphasis on conservation of lampreys is unique to SLIS III and reflects a heightened international recognition that scientific and management advances supporting sea lamprey control in the Great Lakes can benefit the global effort to conserve native lampreys and vice versa
Momentum transfer using chirped standing wave fields: Bragg scattering
We consider momentum transfer using frequency-chirped standing wave fields.
Novel atom-beam splitter and mirror schemes based on Bragg scattering are
presented. It is shown that a predetermined number of photon momenta can be
transferred to the atoms in a single interaction zone.Comment: 4 pages, 3 figure
Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula
[EN] 1,8-cineole defines a typical chemotype of Thymus vulgaris L. in Iberian Peninsula. This compound has a wide range of potentially useful bioactive properties. In order to study the influence of drought stress in the essential oil (EO) composition of this chemotype, sixty plants from six wild populations of Eastern Iberian Peninsula were distilled and analyzed by GC and GC/MS. The harvest dates (May and August) were selected in such a way that the typical summer drought in Mediterranean climates was the critical factor affecting EO composition. Despite the high intrapopulational variability, significant increases of 1,8-cineole were found after the drought period (21.8%-43.2%, in May, up to 42.6%-68.5% in August). On the other hand, individuals from one of the populations showed different profiles rich in linalool and camphor or sesquiterpenoid compounds, such as a-cadinol.Llorens Molina, JA.; Vacas González, S. (2016). Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula. Journal of Essential Oil Research. 29(2):145-155. doi:10.1080/10412905.2016.1211561S14515529
Decays of the Exotic Hybrid and - Mixing
QCD sum-rules are used to calculate the decay widths of the exotic hybrid in two different
mixing schemes.
In the conventional flavour octet-singlet mixing scheme, the decay widths are
both found to be small, while in the recently-proposed quark mixing scheme, the
decay width is large compared with
the decay width . These
results provide some insight into - mixing and hybrid decay
features.Comment: latex2e, 11 pages with 4 embedded eps figures. v 2 corrects reference
[5] and minor error in equation (11
Improved Determination of the Mass of the Light Hybrid Meson From QCD Sum Rules
We calculate the next-to-leading order (NLO) -corrections to the
contributions of the condensates and in the
current-current correlator of the hybrid current
g\barq(x)\gamma_{\nu}iF_{\mu\nu}^aT^aq(x) using the external field method in
Feynman gauge. After incorporating these NLO contributions into the Laplace
sum-rules, the mass of the = light hybrid meson is recalculated
using the QCD sum rule approach. We find that the sum rules exhibit enhanced
stability when the NLO -corrections are included in the sum rule
analysis, resulting in a light hybrid meson mass of approximately 1.6
GeV.Comment: revtex4, 10 pages, 7 eps figures embedded in manuscrip
- …