797 research outputs found
An exploration of the benefits and challenges associated with introducing point-of-care ultrasound to a rural primary care setting
Castleton Family Health Center serves the western portion of Rutland County, which is designated as both rural and medically underserved. The regional Community Health Needs Assessment set goals to increase primary care visits, decrease inappropriate utilization of the emergency department, and work towards seamless care transitions without loss of information or gaps in care. Additionally, the Vermont Department of Health (Rutland region) identified both transportation limitations and a shortage of medical specialists as significant barriers to accessing care in the region. Point-of-care ultrasound may serve to address these community needs by improving the quality and continuity of care provided by primary care physicians.https://scholarworks.uvm.edu/fmclerk/1529/thumbnail.jp
A study of the CDGSH protein family: biophysical and bioinformatic analysis of the [2FE-2S] cluster protein mitoneet
Iron-sulfur clusters, an important class of redox active cofactors, are ligated by protein-based Cys ligands in a variety of nuclearities. Traditionally, these clusters serve as one-electron transfer units, though many clusters are capable of catalytic activity and sensing functions. Recently, a greater number of iron-sulfur clusters with non-Cys ligation have been identified, wherein one or more of the Cys ligands are replaced by an alternative amino acid residue such as His or Asp. In most cases the role of this ligand substitution is unknown. Some hypotheses are that non-Cys ligation may modify reduction potential, allow for proton-coupled electron transfer, or modulate cluster stability. The human mitoNEET protein contains a 1-His, 3-Cys ligated [2Fe-2S] cluster, identified by the presence of a CDGSH peptide motif. MitoNEET is a binding target for the type II-diabetes drug, pioglitazone, and is implicated in controlling mitochondrial iron levels. How exactly mitoNEET functions in the cell is unknown, as is the role its uniquely ligated FeS cluster may play. This thesis uses mitoNEET as a model for the study of non-Cys ligated FeS clusters and their biological function. Protein film voltammetry was used to examine the pH-dependent electrochemical properties of the mitoNEET cluster, indicating that multiple as yet unidentified protonations control redox potential and that drug binding impacts cluster reduction and protonation. Additionally, the effect of reduction and protonation on cluster and protein structure instability was examined through absorbance and circular dichroism measurements, suggesting an important role for cluster lability in protein function. The CDGSH-motif family of [2Fe-2S] cluster-binding proteins was examined using protein similarity networks. This technique highlights the evolutionary relationship among these proteins, and has led to further work examining the DUF1271 domain containing proteins E. coli YjdI and A. vinosum Alvin0680 (a CDGSH-DUF1271 fusion). This work furthers the scientific knowledge of non-Cys ligated Fe-S clusters by improving our understanding of how the mitoNEET His-ligand contributes to proton-coupled electron transfer and cluster instability, and how the broader class of CDGSH-motif proteins is organized
Restriction of Fourier transforms to curves, II: Some classes with vanishing torsion
We consider the Fourier restriction operators associated to certain
degenerate curves in R^d for which the highest torsion vanishes. We prove
estimates with respect to affine arclength and with respect to the Euclidean
arclength measure on the curve. The estimates have certain uniform features,
and the affine arclength results cover families of flat curves.Comment: 26 pages, Final version to appear in the Journal of the Australian
Mathematical Societ
Restriction of Fourier transforms to curves and related oscillatory integrals
We prove sharp endpoint results for the Fourier restriction operator
associated to nondegenerate curves in , , and related
estimates for oscillatory integral operators. Moreover, for some larger classes
of curves in we obtain sharp uniform bounds with
respect to affine arclength measure, thereby resolving a problem of Drury and
Marshall.Comment: Minor changes in the version to appear in American Journal of
Mathematic
A power-law distribution for tenure lengths of sports managers
We show that the tenure lengths for managers of sport teams follow a power law distribution with an exponent between 2 and 3. We develop a simple theoretical model which replicates this result. The model demonstrates that the empirical phenomenon can be understood as the macroscopic outcome of pairwise interactions among managers in a league, threshold effects in managerial performance evaluation, competitive market forces, and luck at the microscopic level
On the Approximability of the Traveling Salesman Problem with Line Neighborhoods
We study the variant of the Euclidean Traveling Salesman problem where
instead of a set of points, we are given a set of lines as input, and the goal
is to find the shortest tour that visits each line. The best known upper and
lower bounds for the problem in , with , are
-hardness and an -approximation algorithm which is
based on a reduction to the group Steiner tree problem.
We show that TSP with lines in is APX-hard for any .
More generally, this implies that TSP with -dimensional flats does not admit
a PTAS for any unless , which gives a
complete classification of the approximability of these problems, as there are
known PTASes for (i.e., points) and (hyperplanes). We are able to
give a stronger inapproximability factor for by showing that TSP
with lines does not admit a -approximation in dimensions
under the unique games conjecture. On the positive side, we leverage recent
results on restricted variants of the group Steiner tree problem in order to
give an -approximation algorithm for the problem, albeit with a
running time of
Built-up structure criticality
The built-up land represents an important type of overall landscape. In this
paper the built-up land structure in the largest cities in the Czech Republic
and selected cities in the U.S.A. is analysed using the framework of
statistical physics. We calculate the variance of the built-up area and the
number variance of built-up landed plots in discs. In both cases the variance
as a function of a disc radius follows a power law. The obtained values of
power law exponents are comparable through different cities. The study is based
on cadastral data from the Czech Republic and building footprints from GIS data
in the U.S.A.Comment: 14 pages, 11 figure
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