7,064 research outputs found
Spatial resolution of a GEM readout TPC using the charge dispersion signal
A large volume Time Projection Chamber (TPC) is being considered for the
central charged particle tracker for the detector for the proposed
International Linear Collider (ILC). To meet the ILC-TPC spatial resolution
challenge of ~100 microns with a manageable number of readout pads and channels
of electronics, Micro Pattern Gas Detectors (MPGD) are being developed which
could use pads comparable in width to the proportional-wire/cathode-pad TPC. We
have built a prototype GEM readout TPC with 2 mm x 6 mm pads using the new
concept of charge dispersion in MPGDs with a resistive anode. The dependence of
transverse resolution on the drift distance has been measured for small angle
tracks in cosmic ray tests without a magnetic field for Ar/CO2 (90:10). The
GEM-TPC resolution with charge dispersion readout is significantly better than
previous measurements carried out with conventional direct charge readout
techniques.Comment: 5 figures, 10 page
Micromegas TPC studies at high magnetic fields using the charge dispersion signal
The International Linear Collider (ILC) Time Projection Chamber (TPC)
transverse space-point resolution goal is 100 microns for all tracks including
stiff 90 degree tracks with the full 2 meter drift. A Micro Pattern Gas
Detector (MPGD) readout TPC can achieve the target resolution with existing
techniques using 1 mm or narrower pads at the expense of increased detector
cost and complexity. The new MPGD readout technique of charge dispersion can
achieve good resolution without resorting to narrow pads. This has been
demonstrated previously for 2 mm x 6 mm pads with GEMs and Micromegas in cosmic
ray tests and in a KEK beam test in a 1 Tesla magnet. We have recently tested a
Micromegas-TPC using the charge dispersion readout concept in a high field
super-conducting magnet at DESY. The measured Micromegas gain was found to be
constant within 0.5% for magnetic fields up to 5 Tesla. With the strong
suppression of transverse diffusion at high magnetic fields, we measure a flat
50 micron resolution at 5 Tesla over the full 15 cm drift length of our
prototype TPC.Comment: 7 pages, 3 figure
Psychological Morbidity in Students of Medical College and Science and Art College Students - A Comparative Study
Considering the importance of quality of life in medical students we have conducted a cross sectional & descriptive study on screening of mental illness of 60 medical students of prefinal year and comparing it with 60 students of third year of Science and Art College. Students were selected via random sampling. GHQ-12 was used as a screening tool and after obtaining scores students were graded in 3 categories - individuals screened positive for psychological morbidity were of Grades 2 and 3 and individuals screened negative for psychological morbidity were of Grade 1 and they were compared according to college, gender & residence. Students screened positive for psychological morbidity as per GHQ-12 were found higher in medical college (87%) as compared to Science and Art College (45%) and a statistically significant association was found between psychological morbidity and medical students. Psychological morbidity was not significantly associated with residence and gender
Analysis of Hepatitis C Viral Dynamics Using Latin Hypercube Sampling
We consider a mathematical model comprising of four coupled ordinary
differential equations (ODEs) for studying the hepatitis C (HCV) viral
dynamics. The model embodies the efficacies of a combination therapy of
interferon and ribavirin. A condition for the stability of the uninfected and
the infected steady states is presented. A large number of sample points for
the model parameters (which were physiologically feasible) were generated using
Latin hypercube sampling. Analysis of our simulated values indicated
approximately 24% cases as having an uninfected steady state. Statistical tests
like the chi-square-test and the Spearman's test were also done on the sample
values. The results of these tests indicate a distinctly differently
distribution of certain parameter values and not in case of others, vis-a-vis,
the stability of the uninfected and the infected steady states
PdTe a 4.5K Type II BCS Superconductor
We report on the structure and physical properties of bulk Palladium
Tellurium superconductor, which is synthesized via quartz vacuum encapsulation
technique at 750 C. The as synthesized compound is crystallized in hexagonal
crystal structure. Magnetization and Magneto-transport measurements provided
the values of lower and upper critical field to be 250 and 1200 Gauss
respectively at 2 Kelvin. The Coherence length and GL parameter are estimated
from the experimentally determined upper and lower critical fields, which are
45 nm and 1.48 respectively. The jump in Cp(T) at Tc is found to be 1.33 and
the Debye temperature and electronic specific heat constant are 203 Kelvin and
6.01mJ/mole-K2 respectively.Comment: 13 pages Text + Figs: Accepted in Sup. Sci. and Tec
Ion-water clusters, bulk medium effects, and ion hydration
Thermochemistry of gas-phase ion-water clusters together with estimates of
the hydration free energy of the clusters and the water ligands are used to
calculate the hydration free energy of the ion. Often the hydration
calculations use a continuum model of the solvent. The primitive quasichemical
approximation to the quasichemical theory provides a transparent framework to
anchor such efforts. Here we evaluate the approximations inherent in the
primitive quasichemical approach and elucidate the different roles of the bulk
medium. We find that the bulk medium can stabilize configurations of the
cluster that are usually not observed in the gas phase, while also
simultaneously lowering the excess chemical potential of the ion. This effect
is more pronounced for soft ions. Since the coordination number that minimizes
the excess chemical potential of the ion is identified as the optimal or most
probable coordination number, for such soft ions, the optimum cluster size and
the hydration thermodynamics obtained without account of the bulk medium on the
ion-water clustering reaction can be different from those observed in
simulations of the aqueous ion. The ideas presented in this work are expected
to be relevant to experimental studies that translate thermochemistry of
ion-water clusters to the thermodynamics of the hydrated ion and to evolving
theoretical approaches that combine high-level calculations on clusters with
coarse-grained models of the medium
Rate Determining Factors in Protein Model Structures
Previous research has shown a strong correlation of protein folding rates to
the native state geometry, yet a complete explanation for this dependence is
still lacking. Here we study the rate-geometry relationship with a simple
statistical physics model, and focus on two classes of model geometries,
representing ideal parallel and antiparallel structures. We find that the
logarithm of the rate shows an almost perfect linear correlation with the
"absolute contact order", but the slope depends on the particular class
considered. We discuss these findings in the light of experimental results.Comment: 4 pages, 2 figure
Race affects SVR12 in a large and ethnically diverse hepatitis C-infected patient population following treatment with direct-acting antivirals: Analysis of a single-center Department of Veterans Affairs cohort.
Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. HCV cure has been linked to improved patient outcomes. In the era of direct-acting antivirals (DAAs), HCV cure has become the goal, as defined by sustained virological response 12 weeks (SVR12) after completion of therapy. Historically, African-Americans have had lower SVR12 rates compared to White people in the interferon era, which had been attributed to the high prevalence of non-CC interleukin 28B (IL28B) type. Less is known about the association between race/ethnicity and SVR12 in DAA-treated era. The aim of the study is to evaluate the predictors of SVR12 in a diverse, single-center Veterans Affairs population. We conducted a retrospective study of patients undergoing HCV therapy with DAAs from 2014 to 2016 at the VA Greater Los Angeles Healthcare System. We performed a multivariable logistic regression analysis to determine predictors of SVR12, adjusting for age, HCV genotype, DAA regimen and duration, human immunodeficiency virus (HIV) status, fibrosis, nonalcoholic fatty liver disease (NAFLD) fibrosis score, homelessness, mental health, and adherence. Our cohort included 1068 patients, out of which 401 (37.5%) were White people and 400 (37.5%) were African-American. Genotype 1 was the most common genotype (83.9%, N = 896). In the adjusted models, race/ethnicity and the presence of fibrosis were statistically significant predictors of non-SVR. African-Americans had 57% lower odds for reaching SVR12 (adj.OR = 0.43, 95% CI = 1.5-4.1) compared to White people. Advanced fibrosis (adj.OR = 0.40, 95% CI = 0.26-0.68) was also a significant predictor of non-SVR. In a single-center VA population on DAAs, African-Americans were less likely than White people to reach SVR12 when adjusting for covariates
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