2,942 research outputs found
Novel Exploration Techniques (NETs) for Malaria Policy Interventions
The task of decision-making under uncertainty is daunting, especially for
problems which have significant complexity. Healthcare policy makers across the
globe are facing problems under challenging constraints, with limited tools to
help them make data driven decisions. In this work we frame the process of
finding an optimal malaria policy as a stochastic multi-armed bandit problem,
and implement three agent based strategies to explore the policy space. We
apply a Gaussian Process regression to the findings of each agent, both for
comparison and to account for stochastic results from simulating the spread of
malaria in a fixed population. The generated policy spaces are compared with
published results to give a direct reference with human expert decisions for
the same simulated population. Our novel approach provides a powerful resource
for policy makers, and a platform which can be readily extended to capture
future more nuanced policy spaces.Comment: Under-revie
The Association Between Latent Tuberculosis Infection and Diabetes Mellitus Control in the United States
Rationale: Diabetes mellitus (DM) is recognized as a common comorbid condition for tuberculosis (TB). Those with comorbid conditions are more likely to develop active TB, to have trouble with treatment, and to have more severe symptoms.
Objective: To measure the prevalence and distribution of latent tuberculosis infection (LTBI) and DM control in the United State and test their association when measured by tuberculin skin test (TST) or QuantiFERON®-TB Gold In-Tube blood test (QFT-GIT) and by HbA1c, respectively. Literature Review: One-third of the world population is infected with TB. Ten percent of TB cases worldwide are linked to diabetes mellitus. Studies have found that the risk of TB increases with the presence of DM.
Methods: This is a cross-sectional, secondary analysis study of the 2011-2012 National Health and Nutrition Examination Survey. The study population included 4,222 participants. Frequency and proportions of each variable were calculated. Then calculations of the frequency and conditional distribution of LTBI for the predictors were made. The chi-square test of association was used to test relationship between LTBI and DM control. Finally, unadjusted and adjusted odds of LTBI were calculated using binary and multiple logistic regressions, respectively.
Main Results: The chi-square test of association found that LTBI and DM control are not independent. The unadjusted logistic regression showed significantly increased odds of having LTBI for those with HbA1c levels corresponding prediabetes and diabetes compared to those with normal HbA1c levels, which the adjusted logistic regression did not.
Conclusion: This study found that LTBI and DM control were associated. There was increased likelihood of having LTBI with poorer diabetes mellitus control, however, the increased odds disappeared when accounting for covariates
Active elastohydrodynamics of vesicles in narrow, blind constrictions
Fluid-resistance limited transport of vesicles through narrow constrictions
is a recurring theme in many biological and engineering applications. Inspired
by the motor-driven movement of soft membrane-bound vesicles into closed
neuronal dendritic spines, here we study this problem using a combination of
passive three-dimensional simulations and a simplified semi-analytical theory
for active transport of vesicles that are forced through such constrictions by
molecular motors. We show that the motion of these objects is characterized by
two dimensionless quantities related to the geometry and the strength of
forcing relative to the vesicle elasticity. We use numerical simulations to
characterize the transit time for a vesicle forced by fluid pressure through a
constriction in a channel, and find that relative to an open channel, transport
into a blind end leads to the formation of an effective lubrication layer that
strongly impedes motion. When the fluid pressure forcing is complemented by
forces due to molecular motors that are responsible for vesicle trafficking
into dendritic spines, we find that the competition between motor forcing and
fluid drag results in multistable dynamics reminiscent of the real system. Our
study highlights the role of non-local hydrodynamic effects in determining the
kinetics of vesicular transport in constricted geometries
Influence of coating on the thermal resistance of a Ni-Based superalloy
In this paper, the influence of M-CrAlY polycrystalline coating on the thermal fatigue behavior of a Nickel-base superalloy has been investigated. A special device using a rotating bending machine and two thermal sources has been used to perform thermo-mechanical tests. The two thermal sources have been set to obtain temperature variations between 750 and 1120 °C in the central part of the specimens, with a frequency of 0.1 Hz. The results showed a deleterious effect of the coating on the fatigue resistance. Numerical simulations have been carried out on SAMCEF to determine the thermo-mechanical field of the so-tested specimens. Calculated thermo-mechanical cycles of critical sites are associated with microstructure evolution and damage by cracking observed on the specimens. Damage mechanisms related to the presence of coating are discussed
Assessment of RNAi-induced silencing in banana (Musa spp.)
In plants, RNA- based gene silencing mediated by small RNAs functions at the transcriptional or post-transcriptional level to negatively regulate target genes, repetitive sequences, viral RNAs and/or transposon elements. Post-transcriptional gene silencing (PTGS) or the RNA interference (RNAi) approach has been achieved in a wide range of plant species for inhibiting the expression of target genes by generating double-stranded RNA (dsRNA). However, to our knowledge, successful RNAi-application to knock-down endogenous genes has not been reported in the important staple food crop banana
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