2,204 research outputs found
A principal component analysis of 39 scientific impact measures
The impact of scientific publications has traditionally been expressed in
terms of citation counts. However, scientific activity has moved online over
the past decade. To better capture scientific impact in the digital era, a
variety of new impact measures has been proposed on the basis of social network
analysis and usage log data. Here we investigate how these new measures relate
to each other, and how accurately and completely they express scientific
impact. We performed a principal component analysis of the rankings produced by
39 existing and proposed measures of scholarly impact that were calculated on
the basis of both citation and usage log data. Our results indicate that the
notion of scientific impact is a multi-dimensional construct that can not be
adequately measured by any single indicator, although some measures are more
suitable than others. The commonly used citation Impact Factor is not
positioned at the core of this construct, but at its periphery, and should thus
be used with caution
Structural shimming for high-resolution nuclear magnetic resonance spectroscopy in lab-on-a-chip devices
High-resolution proton NMR spectroscopy is well-established as a tool for metabolomic analysis of biological fluids at the macro scale. Its full potential has, however, not been realised yet in the context of microfluidic devices. While microfabricated NMR detectors offer substantial gains in sensitivity, limited spectral resolution resulting from mismatches in the magnetic susceptibility of the sample fluid and the chip material remains a major hurdle. In this contribution, we show that susceptibility broadening can be avoided even in the presence of substantial mismatch by including suitably shaped compensation structures into the chip design. An efficient algorithm for the calculation of field maps from arbitrary chip layouts based on Gaussian quadrature is used to optimise the shape of the compensation structure to ensure a flat field distribution inside the sample area. Previously, the complexity of microfluidic NMR systems has been restricted to simple capillaries to avoid susceptibility broadening. The structural shimming approach introduced here can be adapted to virtually any shape of sample chamber and surrounding fluidic network, thereby greatly expanding the design space and enabling true lab-on-a-chip systems suitable for high-resolution NMR detectio
The aDORe Federation Architecture
The need to federate repositories emerges in two distinctive scenarios. In
one scenario, scalability-related problems in the operation of a repository
reach a point beyond which continued service requires parallelization and hence
federation of the repository infrastructure. In the other scenario, multiple
distributed repositories manage collections of interest to certain communities
or applications, and federation is an approach to present a unified perspective
across these repositories. The high-level, 3-Tier aDORe federation architecture
can be used as a guideline to federate repositories in both cases. This paper
describes the architecture, consisting of core interfaces for federated
repositories in Tier-1, two shared infrastructure components in Tier-2, and a
single-point of access to the federation in Tier-3. The paper also illustrates
two large-scale deployments of the aDORe federation architecture: the aDORe
Archive repository (over 100,000,000 digital objects) at the Los Alamos
National Laboratory and the Ghent University Image Repository federation
(multiple terabytes of image files).Comment: 43 pages, 4 figures, 2 table
Duration of patients’ visits to the hospital emergency department
Background
Length of stay is an important indicator of quality of care in Emergency Departments (ED). This study explores the duration of patients’ visits to the ED for which they are treated and released (T&R). Methods
Retrospective data analysis and multivariate regression analysis were conducted to investigate the duration of T&R ED visits. Duration for each visit was computed by taking the difference between admission and discharge times. The Healthcare Cost and Utilization Project (HCUP) State Emergency Department Databases (SEDD) for 2008 were used in the analysis. Results
The mean duration of T&R ED visit was 195.7 minutes. The average duration of ED visits increased from 8 a.m. until noon, then decreased until midnight at which we observed an approximately 70-minute spike in average duration. We found a substantial difference in mean duration of ED visits (over 90 minutes) between Mondays and other weekdays during the transition time from the evening of the day before to the early morning hours. Black / African American patients had a 21.4-minute longer mean duration of visits compared to white patients. The mean duration of visits at teaching hospitals was substantially longer than at non-teaching hospitals (243.8 versus 175.6 minutes). Hospitals with large bed size were associated with longer duration of visits (222.2 minutes) when compared to hospitals with small bed size (172.4 minutes) or those with medium bed size (166.5 minutes). The risk-adjusted results show that mean duration of visits on Mondays are longer by about 4 and 9 percents when compared to mean duration of visits on non-Monday workdays and weekends, respectively. Conclusions
The duration of T&R ED visits varied significantly by admission hour, day of the week, patient volume, patient characteristics, hospital characteristics and area characteristics
Whole genome sequencing-based mapping and candidate identification of mutations from fixed zebrafish tissue
As forward genetic screens in zebrafish become more common, the number of mutants that cannot be identified by gross morphology or through transgenic approaches, such as many nervous system defects, has also increased. Screening for these difficult-to-visualize phenotypes demands techniques such as whole-mount in situ hybridization (WISH) or antibody staining, which require tissue fixation. To date, fixed tissue has not been amenable for generating libraries for whole genome sequencing (WGS). Here, we describe a method for using genomic DNA from fixed tissue and a bioinformatics suite for WGS-based mapping of zebrafish mutants. We tested our protocol using two known zebrafish mutant alleles, gpr126st49 and egr2bfh227, both of which cause myelin defects. As further proof of concept we mapped a novel mutation, stl64, identified in a zebrafish WISH screen for myelination defects. We linked stl64 to chromosome 1 and identified a candidate nonsense mutation in the F-box and WD repeat domain containing 7 (fbxw7) gene. Importantly, stl64 mutants phenocopy previously described fbxw7vu56 mutants, and knockdown of fbxw7 in wild-type animals produced similar defects, demonstrating that stl64 disrupts fbxw7. Together, these data show that our mapping protocol can map and identify causative lesions in mutant screens that require tissue fixation for phenotypic analysis
Secure Arcade: A Gamified Defense Against Cyber Attacks
In modernity, we continually receive increasingly intricate technologies that
allow us to increase our lives convenience and efficiency. Our technology,
particularly technology available over the internet, is advancing at
unprecedented speed. However, this speed of advancement allows those behind
malicious attacks to have an increasingly easier time taking advantage of those
who know little about computer security. Unfortunately, education in the
computer security field is generally limited only to tertiary education. This
research addresses this problem through a gamified web-based application that
drives users to reach learning goals to help them become more vigilant internet
users: 1. Learn and memorize general computer security terminology, 2. Become
familiar with basic cryptography concepts, 3. Learn to recognize potential
phishing scams via email quickly, and 4. Learn common attacks on servers and
how to deal with them
A study of carbon tetrachloride : VI. Aminoaciduria in response to carbon tetrachloride inhalation
The [alpha]-amino acid nitrogen to creatinine nitrogen ratio of normal rats on an ad libitum diet is quite constant and provides a reliable method for determining alterations in amino acid excretion.Exposure of rats to high levels of CCl4 vapor results in increased urinary excretion of free amino acids. There is a simultaneous increase in the corresponding free amino acids of the blood suggesting that increased urinary excretion is a reflection of elevated levels of free amino acids in the blood. The suggestion is made that the source of the elevated serum free amino acids is damaged tissue and, on the basis of the hepatotoxic action of CCl4, one would expect damaged liver cells to be the major source of these free amino acids.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32157/1/0000212.pd
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