132,588 research outputs found
Waiting-time distribution of a discrete-time multiserver queue with correlated arrivals and deterministic service times: D-MAP/D/k system
No full textWe derive the waiting-time distribution of a discrete-time multiserver queue with correlated arrivals and deterministic (or constant) service times. We show that the procedure for obtaining the waiting-time distribution of a multiserver queue is reduced to that of a single-server queue. We present a complete solution to the waiting-time distribution of D-MAP/D/k queue together with some computational results. (C) 2002 Elsevier Science B.V. All rights reserved.BK 21 project, the Department of Industrial Engineering, KAIST, NSER
Quality-of-life indicators and falls due to vitamin D deficiency
No full textMuhammad Raza Cheema, Ahmad Yar Chaudhry Department of Geriatrics, University Hospitals Coventry and Warwickshire, NHS Hospitals, Coventry, UK Objective: To determine whether the number of falls and quality-of-life indicators relate to serum levels of vitamin D, parathyroid hormone (PTH), and calcium levels.Design: A prospective study.Participants: Patients being admitted with a fall with or without sustaining a fragility fracture post fall.Measurements: Measured frequency of falling, SF-12 questionnaire, serum concentrations of 25-hydroxyvitamin D, calcium, and PTH levels before and after treatment with vitamin D supplementation.Results: The mean age (N=38) of the cohort was 80.2±12. In all, 76.3% of the cohort had sustained a fragility fracture after the fall. The cohort was vitamin D deficient with the pretreatment mean value of 24.2±17 nmol/L and posttreatment mean value of 99±40 nmol/L with a statistically significant mean difference of 74.7 nmol/L (confidence interval [CI] 61.27–88.3), P=0.001. The levels of calcium and PTH were statistically significant after treatment with a mean difference of 0.16 (CI 0.1–0.2), P=0.001, and 3.7 (CI –4.8 to –2.5), P=0.001, respectively. After treatment, the mean difference of physical component score (PCS) and mental component score for the whole cohort was 2.9 (CI –0.69 to 6.6), P=0.10, and 1.05 (CI –2.6 to 4.7), P=0.56, respectively. However, a subgroup analysis for cohort aged ≤70 years provided a statistically significant effect on PCS with a mean difference of 8.9 (CI 1.3–16.4), P=0.03, but a statistically insignificant improvement in mental component score with a mean difference of 6.0 (CI –17 to –5.0), P=0.20. However, a statistically significant improvement in PCS SF-12 was observed in patients ≤70 years of age 2.9 (1.3–16.4), P=0.03. The mean number of falls for the whole cohort pre- and posttreatment was 1.11±0.92 vs 0.97±0.99 (P=0.68), respectively.Conclusion: Patients who had fallen and sustained fragility fracture had lower serum 25-dihydroxyvitamin D and higher serum PTH levels. Our study demonstrates that there is no statistically significant improvement in the number of falls after treatment with vitamin D. Overall, vitamin D levels improved significantly, this is despite quality-of-life indicators showing a mean increase in PCS but not a statistically significant improvement. However, statistically significant improvement in PCS was observed in group aged ≤70 years after vitamin D supplementation. Keywords: vitamin D, calcium, SF-12 questionnaire, parathyroid hormon
A novel metabarcoded deep amplicon sequencing tool for the detection of diminazene drug resistance mutations in Trypanosoma evansi
No full textDiminazene resistance of Trypanosoma is an increasing problem whose underlying genetics are not fully understood. The development of diminazene resistance in Trypanosoma brucei is associated with loss of drug uptake by the P2 aminopurine due to alteration in the corresponding adenosine transporter-1 (AT-1) domain. Specific mutant-type alleles (71V, 178T, 181E, 239G, 286S and 380P) linked to resistance were more prevalent in T. brucei subspecies gambiense in humans. In the present study, we have analysed the adenosine transporter-1 (AT-1) domain of the P2 aminopurine from Trypanosoma evansi to explore a possible genetic link between the presence of mutations in this gene and diminazene treatment in ruminants. The genetic basis of diminazene resistance was investigated with a new high-throughput metabarcoded deep amplicon sequencing tool in T. evansi field isolates. We examined Trypanosoma isolates collected from ruminants (Camel, Buffalo, Cattle, Goat, Sheep) in seven known endemic regions of the Punjab province of Pakistan, where animals are treated in a sporadic manner, often with generic diminazene drugs of unknown quality. Blood samples were collected for DNA preparation, adapter/barcoded PCR amplification and Illumina Mi-Seq based sequencing. Our results indicate that 7 T. evansi field isolates had resistance mutations at codon 178E/S, 239Y/A/E, 286S/H/I/D/T in the adenosine transporter-1 (AT-1) domain. In contrast, 26 T. evansi field isolates had susceptible mutations at codon A178, G181, D239 and N286 in the adenosine transporter-1 (AT-1) domain. The overall outcomes will be useful in understanding the emergence of diminazene resistance. This information will help design strategies to optimize the use and lifespan of the most important drug to control trypanosomiasis
Computational analysis of stationary waiting-time distributions of GI(x)/R/1 and GIx/D/1 queues
No full textIn this article, we obtain, in a unified way a closed-form analytic expression, in terms of roots of the so-called characteristic equation of the stationary waiting-time distribution for the Gl/(x)/R/1 queue, where R denotes the class of distributions whose Laplace-Stielijes transforms are rational functions (ratios of a polynomial of degree at most it to a polynomial of degree it). The analysis is not restricted to generalized distributions with phases such as Coxian-n (C-n) but also covers nonphase-type distributions such as deterministic (D). In the latter case, we get approximate results. Numerical results are presented only for (1) the first two moments of waiting time and (2) the probability that waiting time is zero. It is expected that the results obtained from the present study should prove to be useful not only for practitioners but also for queuing theorists who would like to test the accuracies of inequalities. bounds. or approximations
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
REITs and Idiosyncratic Risk
No full textThis study examines various determinants of idiosyncratic risk from the perspective of un-diversified REIT investors, managers holding options, other option holders, and arbitrageurs. Since real estate investment trusts (REITs) enjoy a unique organizational structure and tax status, the relevant determinants derived from the two-stage regression model are different from other industrial firms. Results suggest that efficiency, liquidity and earnings variability are the important determinants of idiosyncratic risk, whereas size and capital do not
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Effects of force detecting sense organs on muscle synergies are correlated with their response properties
No full textZill S, Neff D, Chaudhry S, Exter A, Schmitz J, Büschges A. Effects of force detecting sense organs on muscle synergies are correlated with their response properties. Arthropod Structure & Development. 2017;46(4):564-578
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