187 research outputs found
Non-perturbative renormalization of moments of parton distribution functions
We compute non-perturbatively the evolution of the twist-2 operators
corresponding to the average momentum of non-singlet quark densities. The
calculation is based on a finite-size technique, using the Schr\"odinger
Functional, in quenched QCD. We find that a careful choice of the boundary
conditions, is essential, for such operators, to render possible the
computation. As a by-product we apply the non-perturbatively computed
renormalization constants to available data of bare matrix elements between
nucleon states.Comment: Lattice2003(Matrix); 3 pages, 3 figures. Talk by A.
Continuous external momenta in non-perturbative lattice simulations: a computation of renormalization factors
We discuss the usage of continuous external momenta for computing
renormalization factors as needed to renormalize operator matrix elements.
These kind of external momenta are encoded in special boundary conditions for
the fermion fields. The method allows to compute certain renormalization
factors on the lattice that would have been very difficult, if not impossible,
to compute with standard methods. As a result we give the renormalization group
invariant step scaling function for a twist-2 operator corresponding to the
average momentum of non-singlet quark densities.Comment: 28 pages, 10 figure
The continuum limit of the quark mass step scaling function in quenched lattice QCD
The renormalisation group running of the quark mass is determined
non-perturbatively for a large range of scales, by computing the step scaling
function in the Schroedinger Functional formalism of quenched lattice QCD both
with and without O(a) improvement. A one-loop perturbative calculation of the
discretisation effects has been carried out for both the Wilson and the
Clover-improved actions and for a large number of lattice resolutions. The
non-perturbative computation yields continuum results which are regularisation
independent, thus providing convincing evidence for the uniqueness of the
continuum limit. As a byproduct, the ratio of the renormalisation group
invariant quark mass to the quark mass, renormalised at a hadronic scale, is
obtained with very high accuracy.Comment: 23 pages, 3 figures; minor changes, references adde
Pion parton distribution functions from lattice QCD
We report on recent results for the pion matrix element of the twist-2
operator corresponding to the average momentum of non-singlet quark densities.
For the first time finite volume effects of this matrix element are
investigated and come out to be surprisingly large. We use standard Wilson and
non-perturbatively improved clover actions in order to control better the
extrapolation to the continuum limit. Moreover, we compute, fully
non-perturbatively, the renormalization group invariant matrix element, which
allows a comparison with experimental results in a broad range of energy
scales. Finally, we discuss the remaining uncertainties, the extrapolation to
the chiral limit and the quenched approximation.Comment: Lattice2003(matrix), 3 pages, 4 figure
Utilizing a Multi-Step Consensus-Building Process to Create a Shared Departmental Definition of Community Engagement
A multidisciplinary department at a College of Pharmacy utilized a multi-step consensus-building process to create a shared departmental definition of community engagement that was consistent with the department’s mission and vision. Throughout the consensus building and engaged department process, faculty and staff were given opportunities to participate in community-engaged work and departmental activities, including updates in regular scheduled department meetings. This allowed faculty to have a reference and common understanding of the concept of community engagement when striving towards outlined promotion objectives. A shared understanding of what constitutes community engagement was necessary to ensure that all members of the interdisciplinary department are working toward a common goal and shared vision.
Article Type: Original Researc
Text-to-Movie Authoring of Anatomy Lessons
International audienceWith popular use of multimedia and 3D content in anatomy teaching there is a need for a simple yet comprehensive tool to create and edit pedagogical anatomy video lessons. In this paper we present an automated video authoring tool created for teachers. It takes text written in a novel domain specific language (DSL) called the Anatomy Storyboard Language (ASL) as input and translates it to real time 3D animation. Preliminary results demonstrates the ease of use and effectiveness of the tool for quickly drafting video lessons in realistic medical anatomy teaching scenarios
Extended antenatal antiretroviral use correlates with improved infant outcomes throughout the first year of life
OBJECTIVES: To evaluate the effect of extended antenatal triple antiretroviral therapy (ART) on infant outcomes.
DESIGN: Retrospective cohort study using pooled data from health clinics in Malawi and Mozambique from July 2005 to December 2009.
METHODS: Computerized records of 3273 HIV-infected pregnant women accessing Drug Resource Enhancement Against AIDS and Malnutrition centers were reviewed. ART regimens consisted of nevirapine-based HAART as of 14-25 weeks gestation until 6 months postpartum. Infant infection was determined at 1, 6 and 12 months of age by branched DNA.
RESULTS: A total of 3071 pregnancies resulted in 3148 live births. Lost to follow-up, infant deaths and HIV-1 infection rates at 1 and 12 months were 1.3 and 11.5, 0.8 and 6.7 and 0.8 and 2.0, respectively. Infant HIV-1-free survival at 12 months was 92.5%. Mother-to-child transmission and/or infant deaths correlated with length of maternal antenatal ART by multivariate analysis at 1, 6 and 12 months: 14% in women with more than 30 days of triple antenatal ART and 6.9% in mothers receiving at least 90 days of antenatal ART, P = 0.001. Fifty percent of 54 episodes of transmission occurred in women with higher CD4 cell counts (>350 cells/ÎĽl). Infant mortality was 67/1000, lower than background rates (78-100/1000). Growth failure (weight-for-age Z score <-2) was present in 8% of infants around birth, 6% at 6 months, 23% at 12 months (lower than country-specific rates).
CONCLUSION: Extended antenatal ART is protective against adverse infant outcomes up to 12 months of age even in children born to mothers with higher CD4 cell counts.
PMID: 2088528
HAART as a Strategy for Reduction of HIV-1 Transmission in Sub-Saharan Africa: Survival and Virus Load Parameters from the Drug Resource Enhancement against AIDS and Malnutrition Program
Background: The concept of universal antiretroviral use as a strategy for reduction of new cases of HIV infection has been evaluated in mathematical models as a potential approach to curtailing the Sub-Saharan African epidemic. In order to further substantiate such models, additional strategic parameters based on robust patient data should be considered, including survival of HIV-infected populations under HAART and subject infectivity as determined by HIV RNA levels.
Methods: A retrospective cohort study was conducted in a population of patients enrolled in DREAMcenters throughout sub-Saharan Africa in order to determine survival under HAART. Cox regression analysis was performed evaluating parameters associated with survival such as CD4 cell count, viral load, body mass index (BMI) and hemoglobin (HB) levels. DREAM criteria for HAART initiation included (1) WHO stage 3-4 regardless of CD4 cell value (2) 100,000 copies in any subject. Virus load response to HAART was assessed in a subset of patients.
Results: Adult non-pregnant patients who accessed DREAM centers from 1/2002 to 7/2009 were evaluated. A total of 34,295 patients (22,249 females/12,041 males) were included. Median age was 34 years (IQR:29-42) and median observation time 476 days (IQR:206 –950). Baseline median viral load, CD4 cell counts, HB and BMI values were 4.4 (IQR:3.6-5.0), 243 (IQR:109-416), 10.8 (IQR:9.2-12.4), and 20.3 (IQR:18.3-22.7).Over time 23,795 patients initiated HAART. Cox survival analysis (adjusted for Viral Load and HB) according to CD4 cell strata was performed. The relative risk of death in the lowest CD4 stratum (500) was 3.3 [2.7 –4.1]. Survival estimates at >7 years of HAART ranged from 50% to 95% according to baseline CD4 cell count and HB levels. In a subset of 13,405 subjects who received HAART for >6 months with at least 2 virus load measures available, 55.9% achieved < 50 copies/ml and an additional 19.7% achieved levels < 400 copies/ml (75.6% total). Final median virus load value was 58 (IQ: 0 –2000).
Conclusions: Contrary to more conservative estimates used in mathematical modeling studies, patients in our cohort demonstrated a significant survival benefit even within the lowest CD4 cell stratum. Patients on HAART had low potential infectivity as measured by plasma virus load. Cohort data from African patients can contribute to the further refinement of predictive models
Plasma heavy metal levels correlate with deregulated gene expression of detoxifying enzymes in osteoporotic patients
Heavy metal levels appear to be associated with low bone mineral density (BMD) and the consequent osteoporosis risk, but the relationship with the disease has not been clearly defined. The altered expression pattern of numerous genes, including detoxifying genes, seems to play a pivotal role in this context, leading to increased susceptibility to several diseases, including osteoporosis. The purpose of this study is to analyse circulating heavy metals levels and the expression of detoxifying genes in osteoporotic patients (OPs, n = 31), compared with healthy subjects (CTRs, n = 32). Heavy metals concentration in plasma samples was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and the subsequent expression analysis of NAD(P)H quinone dehydrogenase 1 (NQO1), Catalase (CAT), and Metallothionein 1E (MT1E) genes in Peripheral Blood Mononuclear Cells (PBMCs) was assessed by real-time polymerase chain reaction (qRT-PCR). Copper (Cu), mercury (Hg), molybdenum (Mo) and lead (Pb) were found to be significantly higher in the plasma of OPs compared to CTRs. Analysis of the expression levels of detoxifying genes showed a significant decrease in CAT and MT1E in OP group. In addition, Cu correlated positively with the expression levels of both CAT and MT1E in CTRs group and MT1E in OPs. This study shows an increased circulating concentration of certain metals combined with an altered expression pattern of detoxifying genes in OPs, highlighting a novel aspect to be investigated in order to better characterize the role of metals in the pathogenesis of osteoporosis
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