209 research outputs found
A high resolution daily gridded rainfall dataset (1971-2005) for mesoscale meteorological studies
In this communication, we discuss the development of a very high resolution (0.5° 0.5°) daily rainfall dataset for mesoscale meteorological studies over the Indian region. The dataset was developed using quality-controlled rainfall data from more than 3000 rain gauge stations over India. The analysis consists of daily rainfall data for all the seasons for the period 1971-2005. A well-tested interpolation method (Shepard's method) was used to interpolate the station data into regular grids of 0.5° 0.5° lat. long. After proper validation, it has been found that the present dataset is better compared to other available datasets. A few case studies have been shown to demonstrate the utility of the dataset for different mesoscale meteorological analyses. However, since the data density is not kept uniform, there is a possibility of temporal inhomogeneity and therefore, the present dataset cannot be used for trend analysis. The dataset is freely available from the India Meteorological Department, Pune
Atomistic Simulations of the Motion of an Edge Dislocation in Aluminum Using the Embedded Atom Method
The motion of an edge dislocation is analyzed for temperatures ranging from 10 K to 200 K and for stresses up to 5 GPa. The dislocation velocity versus the applied shear stress curve can be divided into four regimes corresponding to successively higher shear stresses. In the first regime,
the applied shear stress is below the Peierls stress and the dislocation velocity is nominally zero. In the second regime, the dislocation velocity decreases with increasing temperature indicating the presence of a drag due to thermal phonons. In the third regime, the dislocation reaches a sub-sonic limiting velocity that can be predicted by a two-dimensional lattice-dynamics analysis. Such an
analysis predicts a limiting velocity for a moving defect when the phase velocity and the group velocity are equal. If even higher shear stresses are applied, the dislocation travels with a transonic velocity of √2 times the shear wave speed
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Comparison of ductus venosus Doppler and cerebroplacental ratio for the prediction of adverse perinatal outcome in high-risk pregnancies before and after 34 weeks.
INTRODUCTION: The objective of the study was to compare the accuracy of the ductus venosus pulsatility index (DV PI) with that of the cerebroplacental ratio (CPR) for the prediction of adverse perinatal outcome at two gestational ages:  0.05), and did not improve the predictive accuracy of CPR for adverse perinatal outcome (AUC 0.88, 95% CI: 0.79-0.97, AIC 52.9, p  0.05), that did not improve the CPR ability to predict adverse perinatal outcome (AUC 0.80, 95% CI: 0.67-0.92, AIC 106.8, p < 0.0001). The predictive accuracy of CPR prior to 34 weeks persisted when the gestational age at delivery was included in the model (AUC 0.91, 95% CI: 0.81-1.00, AIC 46.3, p < 0.0001, vs AUC 0.86, 95% CI: 0.72-1, AIC 56.1, p < 0.0001), and therefore was not determined by prematurity. CONCLUSIONS: CPR predicts adverse perinatal outcome better than DV PI, regardless of gestational age. Larger prospective studies are needed to delineate the role of ultrasound tools of fetal wellbeing assessment in predicting and preventing adverse perinatal outcome
Fracture in Mode I using a Conserved Phase-Field Model
We present a continuum phase-field model of crack propagation. It includes a
phase-field that is proportional to the mass density and a displacement field
that is governed by linear elastic theory. Generic macroscopic crack growth
laws emerge naturally from this model. In contrast to classical continuum
fracture mechanics simulations, our model avoids numerical front tracking. The
added phase-field smoothes the sharp interface, enabling us to use equations of
motion for the material (grounded in basic physical principles) rather than for
the interface (which often are deduced from complicated theories or empirical
observations). The interface dynamics thus emerges naturally. In this paper, we
look at stationary solutions of the model, mode I fracture, and also discuss
numerical issues. We find that the Griffith's threshold underestimates the
critical value at which our system fractures due to long wavelength modes
excited by the fracture process.Comment: 10 pages, 5 figures (eps). Added 2 figures and some text. Removed one
section (and a figure). To be published in PR
Severe Mental Illness Among Adults with Atopic Eczema or Psoriasis: Population-Based Matched Cohort Studies within UK Primary Care
BACKGROUND: Existing research exploring associations between atopic eczema (AE) or psoriasis, and severe mental illness (SMI – ie, schizophrenia, bipolar disorder, other psychoses) is limited, with longitudinal evidence particularly scarce. Therefore, temporal directions of associations are unclear. We aimed to investigate associations between AE or psoriasis and incident SMI among adults. METHODS: We conducted matched cohort studies using primary care electronic health records (January 1997 to January 2020) from the UK Clinical Practice Research Datalink GOLD. We identified two cohorts: 1) adults (≥ 18 years) with and without AE and 2) adults with and without psoriasis. We matched (on age, sex, general practice) adults with AE or psoriasis with up to five adults without. We used Cox regression, stratified by matched set, to estimate hazard ratios (HRs) comparing incident SMI among adults with and without AE or psoriasis. RESULTS: We identified 1,023,232 adults with AE and 4,908,059 without, and 363,210 with psoriasis and 1,801,875 without. After adjusting for matching variables (age, sex, general practice) and potential confounders (deprivation, calendar period) both AE and psoriasis were associated with at least a 17% increased hazard of SMI (AE: HR=1.17,95% CI=1.12– 1.22; psoriasis: HR=1.26,95% CI=1.18– 1.35). After additionally adjusting for potential mediators (comorbidity burden, harmful alcohol use, smoking status, body mass index, and, in AE only, sleep problems and high-dose glucocorticoids), associations with SMI did not persist for AE (HR=0.98,95% CI=0.93– 1.04), and were attenuated for psoriasis (HR=1.14,95% CI=1.05– 1.23). CONCLUSION: Our findings suggest adults with AE or psoriasis are at increased risk of SMI compared to matched comparators. After adjusting for potential mediators, associations with SMI did not persist for AE, and were attenuated for psoriasis, suggesting that the increased risk may be explained by mediating factors (eg, sleep problems). Our research highlights the importance of monitoring mental health in adults with AE or psoriasis
Simulated dynamics and thermodynamics processes leading to the rapid intensification of rare tropical cyclones over the North Indian Oceans
The life cycle dynamics and intensification processes of three long-duration tropical cyclones (TCs), viz., Fani (2019), Luban (2018), and Ockhi (2017) formed over the North Indian Ocean (NIO) have been investigated by developing a high-resolution (6 km × 6 km) mesoscale analysis using WRF and En3DVAR data assimilation system. The release of CAPE in nearly saturated middle-level relative humidity caused intense diabatic heating, leading to an increase in low-level convergence triggering rapid intensification (RI). The strengthening of the relative vorticity tendency terms was due to vertical stretching (TC Fani) and middle tropospheric advection (TCs Luban and Ockhi). The increase or decrease in upper-tropospheric divergence led to RI through two different mechanisms. The increase in upper divergence strengthens the vortical convection (in TC Luban and Fani) by enhancing the moisture and heat transport, whereas its decrease caused a reduction in the upper-level ventilation flow at 200 hPa followed by moisture accumulation, enhanced diabatic heating, and strengthened the warm core (TC Ockhi). The RI caused the vortex of three cyclones to extend up to the upper troposphere. The well organised wind during RI led the unorganised, weak, discontinuous vertical vortex columns to become organised with intense vertical velocity throughout the column. Spatial distributions of Okubo–Wiess (OW) parameter showed TC core dominated by vorticity than strain, since deep depression (DD) stages
Sequence dependence of the folding of collagen-like peptides: Single amino acids affect the rate of triple-helix nucleation
The refolding of thermally denatured model collagen-like peptides was studied for a set of 21 guest triplets embedded in a common host framework: acetyl-(Gly-Pro-Hyp)3-Gly-Xaa-Yaa-(Gly-Pro-Hyp)4-Gly-Gly-amide. The results show a strong dependence of the folding rate on the identity of the guest Gly-Xaa-Yaa triplet, with the half-times for refolding varying from 6 to 110 min (concentration = 1 mg/ml). All triplets of the form Gly-Xaa-Hyp promoted rapid folding, with the rate only marginally dependent on the residue in the Xaa position. In contrast, triplets of the form Gly-Pro-Yaa and Gly-Xaa-Yaa were slower and showed a wide range of half-times, varying with the identity of the residues in the triplet. At low concentrations, the folding can be described by third-order kinetics, suggesting nucleation is rate-limiting. Data on the relative nucleation ability of different Gly-Xaa-Yaa triplets support the favorable nature of imino acids, the importance of hydroxyproline, the varying effects of the same residue in the Xaa position versus the Yaa position, and the difficulties encountered when leucine or aspartic acid are in the Yaa position. Information on the relative propensities of different tripeptide sequences to promote nucleation of the triple-helix in peptides will aid in identification of nucleation sites in collagen sequences
Long-term oral antibiotic use in people with acne vulgaris in UK primary care: a drug utilization study
BACKGROUND: The inappropriate use of antibiotics is understood to contribute to antimicrobial resistance. Oral antibiotics are regularly used to treat moderate-to-severe acne vulgaris. In practice, we do not know the typical length of oral antibiotic treatment courses for acne in routine primary care and what proportion of people receive more than one course of treatment following a new acne diagnosis. OBJECTIVES: To describe how oral antibiotics are prescribed for acne over time in UK primary care. METHODS: We conducted a descriptive longitudinal drug utilization study using routinely collected primary care data from the Clinical Practice Research Datalink GOLD (2004-2019). We included individuals (8-50 years) with a new acne diagnosis recorded between 1 January 2004 and 31 July 2019. RESULTS: We identified 217 410 people with a new acne diagnosis. The median age was 17 years [interquartile range (IQR) 15-25] and median follow-up was 4.3 years (IQR 1.9-7.6). Among people with a new acne diagnosis, 96 703 (44.5%) received 248 560 prescriptions for long-term oral antibiotics during a median follow-up of 5.3 years (IQR 2.8-8.5). The median number of continuous courses of antibiotic therapy (≥ 28 days) per person was four (IQR 2-6). The majority (n = 59 010, 61.0%) of first oral antibiotic prescriptions in those with a recorded acne diagnosis were between the ages of 12 and 18. Most (n = 71 544, 74.0%) first courses for oral antibiotics were for between 28 and 90 days. The median duration of the first course of treatment was 56 days (IQR 50-93 days) and 18 127 (18.7%) of prescriptions of ≥ 28 days were for < 6 weeks. Among people who received a first course of oral antibiotic for ≥ 28 days, 56 261 (58.2%) received a second course after a treatment gap of ≥ 28 days. The median time between first and second courses was 135 days (IQR 67-302). The cumulative duration of exposure to oral antibiotics during follow-up was 255 days (8.5 months). CONCLUSIONS: Further work is needed to understand the consequences of using antibiotics for shorter periods than recommended. Suboptimal treatment duration may result in reduced clinical effectiveness or repeated exposures, potentially contributing to antimicrobial resistance
Atomistic simulations of dislocation mobility in Al, Ni and Al/Mg alloys
Dislocation velocities and mobilities are studied by Molecular Dynamics
simulations for edge and screw dislocations in pure aluminum and nickel, and
edge dislocations in Al-2.5%Mg and Al-5.0%Mg random substitutional alloys using
EAM potentials. In the pure materials, the velocities of all dislocations are
close to linear with the ratio of (applied stress)/(temperature) at low
velocities, consistent with phonon drag models and quantitative agreement with
experiment is obtained for the mobility in Al. At higher velocities, different
behavior is observed. The edge dislocation velocity remains dependent solely on
(applied stress)/(temperature) up to approximately 1.0 MPa/K, and approaches a
plateau velocity that is lower than the smallest "forbidden" speed predicted by
continuum models. In contrast, above a velocity around half of the smallest
continuum wave speed, the screw dislocation damping has a contribution
dependent solely on stress with a functional form close to that predicted by a
radiation damping model of Eshelby. At the highest applied stresses, there are
several regimes of nearly constant (transonic or supersonic) velocity separated
by velocity gaps in the vicinity of forbidden velocities; various modes of
dislocation disintegration and destabilization were also encountered in this
regime. In the alloy systems, there is a temperature- and
concentration-dependent pinning regime where the velocity drops sharply below
the pure metal velocity. Above the pinning regime but at moderate stresses, the
velocity is again linear in (applied stress)/(temperature) but with a lower
mobility than in the pure metal.Comment: PDF, 30 pages including figures, submitted to Modelling Simul. Mater.
Sci. En
Coordinated Cellular Neighborhoods Orchestrate Antitumoral Immunity at the Colorectal Cancer Invasive Front.
Antitumoral immunity requires organized, spatially nuanced interactions between components of the immune tumor microenvironment (iTME). Understanding this coordinated behavior in effective versus ineffective tumor control will advance immunotherapies. We re-engineered co-detection by indexing (CODEX) for paraffin-embedded tissue microarrays, enabling simultaneous profiling of 140 tissue regions from 35 advanced-stage colorectal cancer (CRC) patients with 56 protein markers. We identified nine conserved, distinct cellular neighborhoods (CNs)-a collection of components characteristic of the CRC iTME. Enrichment of PD-1+CD4+ TÂ cells only within a granulocyte CN positively correlated with survival in a high-risk patient subset. Coupling of tumor and immune CNs, fragmentation of TÂ cell and macrophage CNs, and disruption of inter-CN communication was associated with inferior outcomes. This study provides a framework for interrogating how complex biological processes, such as antitumoral immunity, occur through concerted actions of cells and spatial domains
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