200 research outputs found
Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega
High-statistics differential cross sections and spin density matrix elements
for the reaction gamma p -> p omega have been measured using the CLAS at
Jefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV.
Results are reported in 112 10-MeV wide CM energy bins, each subdivided into
cos(theta_CM) bins of width 0.1. These are the most precise and extensive omega
photoproduction measurements to date. A number of prominent structures are
clearly present in the data. Many of these have not previously been observed
due to limited statistics in earlier measurements
Exclusive electroproduction on the proton at CLAS
The reaction has been measured, using the 5.754
GeV electron beam of Jefferson Lab and the CLAS detector. This represents the
largest ever set of data for this reaction in the valence region. Integrated
and differential cross sections are presented. The , and
dependences of the cross section are compared to theoretical calculations based
on -channel meson-exchange Regge theory on the one hand and on quark handbag
diagrams related to Generalized Parton Distributions (GPDs) on the other hand.
The Regge approach can describe at the 30% level most of the features
of the present data while the two GPD calculations that are presented in this
article which succesfully reproduce the high energy data strongly underestimate
the present data. The question is then raised whether this discrepancy
originates from an incomplete or inexact way of modelling the GPDs or the
associated hard scattering amplitude or whether the GPD formalism is simply
inapplicable in this region due to higher-twists contributions, incalculable at
present.Comment: 29 pages, 29 figure
Lattice Boltzmann simulations of soft matter systems
This article concerns numerical simulations of the dynamics of particles
immersed in a continuum solvent. As prototypical systems, we consider colloidal
dispersions of spherical particles and solutions of uncharged polymers. After a
brief explanation of the concept of hydrodynamic interactions, we give a
general overview over the various simulation methods that have been developed
to cope with the resulting computational problems. We then focus on the
approach we have developed, which couples a system of particles to a lattice
Boltzmann model representing the solvent degrees of freedom. The standard D3Q19
lattice Boltzmann model is derived and explained in depth, followed by a
detailed discussion of complementary methods for the coupling of solvent and
solute. Colloidal dispersions are best described in terms of extended particles
with appropriate boundary conditions at the surfaces, while particles with
internal degrees of freedom are easier to simulate as an arrangement of mass
points with frictional coupling to the solvent. In both cases, particular care
has been taken to simulate thermal fluctuations in a consistent way. The
usefulness of this methodology is illustrated by studies from our own research,
where the dynamics of colloidal and polymeric systems has been investigated in
both equilibrium and nonequilibrium situations.Comment: Review article, submitted to Advances in Polymer Science. 16 figures,
76 page
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Influence of women's autonomy on infant mortality in Nepal
<p>Abstract</p> <p>Background</p> <p>Nepalese women lag behind men in many areas, such as educational attainment, participation in decision-making and health service utilization, all of which have an impact on reproductive health outcomes. This paper aims to examine the factors influencing infant mortality, specifically, whether women's autonomy has an impact on infant mortality in the Nepali context.</p> <p>Methods</p> <p>Data were drawn from the Nepal Demographic and Health Survey, 2006. The analysis is confined to 5,545 children who were born within the five years preceding the survey. Association between infant mortality and the explanatory variables was assessed using bivariate analysis. Variables were then re-examined in multivariate analysis to assess the net effect of women's autonomy on infant mortality after controlling for other variables.</p> <p>Results</p> <p>The infant mortality rate (IMR) in the five years preceding the survey was 48 deaths per one thousand live births. Infant mortality rate was high among illiterate women (56 per 1000 live births) and among those not involved in decision making for health care (54 per 1000 live births). Furthermore, infant mortality was high among those women who had more children than their comparison group, who had birth intervals of less than two years, who had multiple births, who were from rural areas, who were poor, whose source of water was the river or unprotected sources, and who did not have a toilet facility in their household.</p> <p>Results from logistic regression show that women's autonomy plays a major role in infant mortality after controlling other variables, such as mother's sociodemographic characteristics, children's characteristics and other household characteristics. Children from literate women had a 32 percent lower chance (OR = 0.68) of experiencing infant mortality than did children from illiterate women. Furthermore, infants of women who were involved in decision-making regarding their own health care had a 25 percent lower (OR = 0.75) chance of dying than did infants whose mothers who were not involved in healthcare decisions.</p> <p>Conclusion</p> <p>Infant mortality is high in Nepal. In this context, mother's literacy and involvement in healthcare decision making appear to be the most powerful predictors for reducing infant mortality. Hence, in order to reduce infant mortality further, ongoing female education should be sustained and expanded to include all women so that the millennium development goals for the year 2015 can be attained. In addition, programs should focus on increasing women's autonomy so that infant mortality will decrease and the overall well being of the family can be maintained and enhanced.</p
Hydroclimatic Contrasts Over Asian Monsoon Areas and Linkages to Tropical Pacific SSTs
Knowledge of spatial and temporal hydroclimatic differences is critical in understanding climatic mechanisms. Here we show striking hydroclimatic contrasts between northern and southern parts of the eastern margin of the Tibetan Plateau (ETP), and those between East Asian summer monsoon (EASM) and Indian summer monsoon (ISM) areas during the past ~2,000 years. During the Medieval Period, and the last 100 to 200 years, the southern ETP (S-ETP) area was generally dry (on average), while the northern ETP (N-ETP) area was wet. During the Little Ice Age (LIA), hydroclimate over S-ETP areas was wet, while that over N-ETP area was dry (on average). Such hydroclimatic contrasts can be broadly extended to ISM and EASM areas. We contend that changes in sea surface temperatures (SSTs) of the tropical Pacific Ocean could have played important roles in producing these hydroclimatic contrasts, by forcing the north-south movement of the Intertropical Convergence Zone (ITCZ) and intensification/slowdown of Walker circulation. The results of sensitivity experiments also support such a proposition
A genome-wide association scan implicates <i>DCHS2, RUNX2, GLI3, PAX1</i> and <i>EDAR</i> in human facial variation
We report a genome-wide association scan for facial features in ∼6,000 Latin Americans. We evaluated 14 traits on an ordinal scale and found significant association (P values−8) at single-nucleotide polymorphisms (SNPs) in four genomic regions for three nose-related traits: columella inclination (4q31), nose bridge breadth (6p21) and nose wing breadth (7p13 and 20p11). In a subsample of ∼3,000 individuals we obtained quantitative traits related to 9 of the ordinal phenotypes and, also, a measure of nasion position. Quantitative analyses confirmed the ordinal-based associations, identified SNPs in 2q12 associated to chin protrusion, and replicated the reported association of nasion position with SNPs in PAX3. Strongest association in 2q12, 4q31, 6p21 and 7p13 was observed for SNPs in the EDAR, DCHS2, RUNX2 and GLI3 genes, respectively. Associated SNPs in 20p11 extend to PAX1. Consistent with the effect of EDAR on chin protrusion, we documented alterations of mandible length in mice with modified Edar function
The extraction of total cross section from
We report on the first measurement of the differential cross section of
-meson photoproduction for the exclusive
reaction channel. The experiment was performed using a
\textcolor{black}{tagged-photon} beam and the CEBAF Large Acceptance
Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the
channel and those from a previous publication on
coherent production on the deuteron has been carried out to extract the
total cross section, . The extracted total
cross section favors a value above 20 mb. This value is larger than the value
extracted using vector-meson dominance models for photoproduction on the
proton.Comment: 7 pages 4 figure
Review article: Use of ultrasound in the developing world
As portability and durability improve, bedside, clinician-performed ultrasound is seeing increasing use in rural, underdeveloped parts of the world. Physicians, nurses and medical officers have demonstrated the ability to perform and interpret a large variety of ultrasound exams, and a growing body of literature supports the use of point-of-care ultrasound in developing nations. We review, by region, the existing literature in support of ultrasound use in the developing world and training guidelines currently in use, and highlight indications for emergency ultrasound in the developing world. We suggest future directions for bedside ultrasound use and research to improve diagnostic capacity and patient care in the most remote areas of the globe
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