133,051 research outputs found
The role of vitamin D in glycaemic control
No full textLips, P.T.A.M. [Promotor]Simsek, S. [Copromotor
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
APPLICATIONS OF POINT PROCESS MODELS TO IMAGING AND BIOLOGY
No full textThis dissertation deals with point process models and their applications to imaging and messenger RNA (mRNA) transcription. We address three problems. The first problem arises in two-photon laser scanning microscopy. We model the process by which photons are counted by a detector which suffers from a dead period upon registration of a photon. In this model, we assume that there are a Poisson (α) number of excited molecules, with exponentially distributed waiting times for the emissions of photons. We derive the exact distribution of all observed counts, rather than grouped counts which were used earlier. We use it to get improved estimates of the Poisson intensity, which leads to images with higher signal-to-noise ratio. This improvement is because grouping of count data results in loss of information. We illustrate this improvement on imaging data of paper fibers. Next, we study two variants of this model: the first uses a finite time horizon and the second considers gamma waiting times for the emissions.
The second problem concerns the Conway-Maxwell-Poisson distribution for count data. This family has been proposed as a generalization of the Poisson for handling overdispersion and underdisperson. Because the normalizing constant of this family is hard to compute, good approximations for it are needed. We provide a statistical approach to derive an existing approximation more simply. However, this approximation does not perform well across all the parameter ranges. Therefore, we introduce correction terms to improve its performance. For other parts of the parameter space, we use the geometric and Bernoulli distributions, with correction terms based on Taylor expansions. Using numerical examples, we show that our approximations are much better than earlier proposed methods.
In the last problem, we present a new application for Conway-Maxwell-Poisson family.
We use the generalized linear model setting of this family to study mRNA counts. We then compare its performance with the existing methods used for modeling mRNAs, such as the negative binomial. This empirical model can be a good modeling tool for dispersed mRNA count data when a biophysically based model is not available
"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 Vitamin D treatment on thyroid autoimmunity
No full textBackground: Vitamin D was shown to be related to autoimmune thyroid diseases (AITDs) in the previous studies. We aimed to investigate the relationship between Vitamin D and thyroid autoimmunity. Materials and Methods: Eighty-two patients, diagnosed with AITD by the endocrinology outpatient clinic, were included in this prospective study. All of the patients had both AITD and Vitamin D deficiency, defined as serum values <20 ng/mL. They were randomly assigned into two groups. The first group included 46 patients and the second one included 36 patients. The first group was treated with Vitamin D for 1 month at 1000 IU/day. The second group served as the control group and was not treated with Vitamin D replacement. Serum thyroid-stimulating hormone, free T4 (fT4), thyroid peroxidase antibody (TPO-Ab), thyroglobulin antibody (TgAb), and Vitamin D levels were measured at the initiation of the study and again at 1 month in all patients. Results: Two groups were similar with regard to age, sex, and type of thyroid disease. Whereas TPO-Ab (before; 278.3 ± 218.4 IU/ml and after; 267.9 ± 200.7 IU/ml) and TgAb (before; 331.9 ± 268.1 IU/ml and after; 275.4 ± 187.3 IU/ml) levels were significantly decreased by the Vitamin D replacement therapy in group 1 (P = 0.02, P = 0.03, respectively), the evaluated parameters in the control group did not significantly change (P = 0.869, P = 0.530, respectively). In addition, thyroid function tests did not significantly change with Vitamin D replacement in two groups. Conclusion: Vitamin D deficiency may contribute to the pathogenesis of AITDs. Since supplementation of the Vitamin D decreased thyroid antibody titers in this study in Vitamin D deficient subjects, in the future Vitamin D may become a part of AITDs' treatment, especially in those with Vitamin D insufficiency. Further clinical and experimental studies are required to understand the effect of Vitamin D on AITD
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
Emergency room management of acute bronchiolitis: a randomized trial of nebulized epinephrine
No full textSimsek-Kiper PO, Kiper N, Hascelik G, Dolgun A, Yalcin E, Dogru-Ersoz D, Ozcelik U. Emergency room management of acute bronchiolitis: a randomized trial of nebulized epinephrine. Turk J Pediatr 2011; 53: 651-660
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