186 research outputs found
ON COMPUTING A BUY/COPY POLICY USING THE PITT-KRAFT MODEL
The Pitt-Kraft model of buying versus photocopying results in a small, but complex, nonlinear program. This paper identifies a Kuhn-Tucker point and demonstrates that for certain parameter values it is not optimal. A policy generation procedure is presented; the purpose is to prevent convergence of a primal algorithm to this inferior policy, which satisfies the Kuhn-Tucker optimality conditions
Centerscope
Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.
Information Literacy Competencies and Copyright in Brazilian Higher Education Institutions
RESUMEN: La competencia informacional o alfabetización informacional (COINFO/ALFIN) es la evolución natural de la antigua formación de usuarios en las bibliotecas adaptada a los nuevos tiempos, donde la tecnología juega un importante papel. Por su parte, el uso ético y legal de la información es una de las competencias que conforman este tipo de formación dentro de los estándares internacionales COINFO/ALFIN. Con el objetivo de conocer la repercusión del uso ético y legal de la información dentro de estos planes formativos de las bibliotecas de educación superior en Brasil, se diseñó un breve cuestionario en línea para averiguar si poseen un plan de COINFO o de formación de usuarios, si dentro de los planes se trata el uso ético y legal de la información y los derechos de autor, en qué consiste esta información cuando se produce, y si las bibliotecas disponen de personal preparado para atender dudas sobre estas cuestiones. De los resultados se desprende que las bibliotecas de educación superior en Brasil aún tienen un largo camino por recorrer en materia de COINFO. No todas tienen planes adecuados para sus usuarios y entre los que sí tienen, cuando se habla sobre derechos de autor, el discurso se centra en los aspectos sancionadores de los mismos, sin dar cabida a la formación que permita saber a autores y usuarios qué derechos tienen, cómo usar las obras de terceros o cómo pueden compartir sus obras, entre otros.ABSTRACT: Information literacy (IL) is the natural evolution of the old “user training” in libraries, adapted to the new times where technology plays an important role. Legal and ethical use of information is one of the competencies incorporated in important international standards of IL. In order to know the impact of the ethical and legal use of information within these training plans in libraries of higher education entities in Brazil, a brief online questionnaire was designed and executed. The questionnaire aimed to research the existence of plans for IL and/or user training , the ethical and legal use of information, copyright, what kind of information they show, and the availability of staff members at libraries to address concerns on these issues. The results show that libraries of higher education entities in Brazil still have a lot of work to do in our area. Not all of them have adequate education plans for their users and those who do have them, and also include some information about copyright, the discourse focuses on disciplinary aspects, without training authors nor users about their rights, how to use the work of others, how to share their own work, amongst others
Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. II. Test of Theoretical Stellar Isochrones
We perform an extensive test of theoretical stellar models for main-sequence
stars in ugriz, using cluster fiducial sequences obtained in the previous paper
of this series. We generate a set of isochrones using the Yale Rotating
Evolutionary Code (YREC) with updated input physics, and derive magnitudes and
colors in ugriz from MARCS model atmospheres. These models match cluster main
sequences over a wide range of metallicity within the errors of the adopted
cluster parameters. However, we find a large discrepancy of model colors at the
lower main sequence (Teff < ~4500 K) for clusters at and above solar
metallicity. We also reach similar conclusions using the theoretical isochrones
of Girardi et al. and Dotter et al., but our new models are generally in better
agreement with the data. Using our theoretical isochrones, we also derive
main-sequence fitting distances and turn-off ages for five key globular
clusters, and demonstrate the ability to derive these quantities from
photometric data in the Sloan Digital Sky Survey. In particular, we exploit
multiple color indices (g - r, g - i, and g - z) in the parameter estimation,
which allows us to evaluate internal systematic errors. Our distance estimates,
with an error of sigma(m - M) = 0.03-0.11 mag for individual clusters, are
consistent with Hipparcos-based subdwarf fitting distances derived in the
Johnson-Cousins or Stromgren photometric systems.Comment: 26 pages, 28 figures. Accepted for publication in ApJ. Version with
high resolution figures available at
http://spider.ipac.caltech.edu/~deokkeun/sdss_iso.pd
Bartonella seropositivity in children with Henoch-Schonlein purpura
BACKGROUND: An association between Henoch-Schonlein purpura (HSP) and seropositivity for Bartonella henselae (BH) has been described. The objective of this study was to see if such an association exists in northern Alberta. METHODS: Immunofluorescent antibody testing utilizing an antigen prepared from B. henselae was undertaken on sera from six children with current HSP, 22 children with remote HSP, and 28 controls that were matched for age. Blood from the six children with current HSP was analysed by polymerase chain reaction (PCR) assay with primers derived from the citrate synthase (gltA) gene for the detection of Bartonella DNA. RESULTS: The seropositivity rate for BH was 61% in cases versus 21% in controls (p < 0.03). The PCR assay was negative in all six current cases. CONCLUSION: There is an increased seropositivity rate for BH in children with HSP. However, it is not clear if infection with B. henselae or a related Bartonella species can result in HSP, or if the increased seropositivity is from non-specific or cross-reacting antibodies
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Estrogen pathway polymorphisms in relation to primary open angle glaucoma: An analysis accounting for gender from the United States
Purpose Circulating estrogen levels are relevant in glaucoma phenotypic traits. We assessed the association between an estrogen metabolism single nucleotide polymorphism (SNP) panel in relation to primary open angle glaucoma (POAG), accounting for gender. Methods: We included 3,108 POAG cases and 3,430 controls of both genders from the Glaucoma Genes and Environment (GLAUGEN) study and the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium genotyped on the Illumina 660W-Quad platform. We assessed the relation between the SNP panels representative of estrogen metabolism and POAG using pathway- and gene-based approaches with the Pathway Analysis by Randomization Incorporating Structure (PARIS) software. PARIS executes a permutation algorithm to assess statistical significance relative to the pathways and genes of comparable genetic architecture. These analyses were performed using the meta-analyzed results from the GLAUGEN and NEIGHBOR data sets. We evaluated POAG overall as well as two subtypes of POAG defined as intraocular pressure (IOP) ≥22 mmHg (high-pressure glaucoma [HPG]) or IOP 0.99). Among women, gene-based analyses revealed that the catechol-O-methyltransferase gene showed strong associations with HTG (permuted gene p≤0.001) and NPG (permuted gene p=0.01). Conclusions: The estrogen SNP pathway was associated with POAG among women
A Common Variant in MIR182 Is Associated With Primary Open-Angle Glaucoma in the NEIGHBORHOOD Consortium
PURPOSE. Noncoding microRNAs (miRNAs) have been implicated in the pathogenesis of glaucoma. We aimed to identify common variants in miRNA coding genes (MIR) associated with primary open-angle glaucoma (POAG).
METHODS. Using the NEIGHBORHOOD data set (3853 cases/33,480 controls with European ancestry), we first assessed the relation between 85 variants in 76 MIR genes and overall POAG. Subtype-specific analyses were performed in high-tension glaucoma (HTG) and normal-tension glaucoma subsets. Second, we examined the expression of miR-182, which was associated with POAG, in postmortem human ocular tissues (ciliary body, cornea, retina, and trabecular meshwork [TM]), using miRNA sequencing (miRNA-Seq) and droplet digital PCR (ddPCR). Third, miR-182 expression was also examined in human aqueous humor (AH) by using miRNA-Seq. Fourth, exosomes secreted from primary human TM cells were examined for miR-182 expression by using miRNA-Seq. Fifth, using ddPCR we compared miR182 expression in AH between five HTG cases and five controls.
RESULTS. Only rs76481776 in MIR182 gene was associated with POAG after adjustment for multiple comparisons (odds ratio [OR] ¼ 1.23, 95% confidence interval [CI]: 1.11–1.42, P ¼ 0.0002). Subtype analysis indicated that the association was primarily in the HTG subset (OR ¼ 1.26, 95% CI: 1.08–1.47, P ¼ 0.004). The risk allele T has been associated with elevated miR-182 expression in vitro. Data from ddPCR and miRNA-Seq confirmed miR-182 expression in all examined ocular tissues and TM-derived exosomes. Interestingly, miR-182 expression in AH was 2-fold higher in HTG patients than nonglaucoma controls (P ¼ 0.03) without controlling for medication treatment.
CONCLUSIONS. Our integrative study is the first to associate rs76481776 with POAG via elevated miR-182 expression
A Common Variant in MIR182 Is Associated With Primary Open-Angle Glaucoma in the NEIGHBORHOOD Consortium
PURPOSE. Noncoding microRNAs (miRNAs) have been implicated in the pathogenesis of glaucoma. We aimed to identify common variants in miRNA coding genes (MIR) associated with primary open-angle glaucoma (POAG).
METHODS. Using the NEIGHBORHOOD data set (3853 cases/33,480 controls with European ancestry), we first assessed the relation between 85 variants in 76 MIR genes and overall POAG. Subtype-specific analyses were performed in high-tension glaucoma (HTG) and normal-tension glaucoma subsets. Second, we examined the expression of miR-182, which was associated with POAG, in postmortem human ocular tissues (ciliary body, cornea, retina, and trabecular meshwork [TM]), using miRNA sequencing (miRNA-Seq) and droplet digital PCR (ddPCR). Third, miR-182 expression was also examined in human aqueous humor (AH) by using miRNA-Seq. Fourth, exosomes secreted from primary human TM cells were examined for miR-182 expression by using miRNA-Seq. Fifth, using ddPCR we compared miR182 expression in AH between five HTG cases and five controls.
RESULTS. Only rs76481776 in MIR182 gene was associated with POAG after adjustment for multiple comparisons (odds ratio [OR] ¼ 1.23, 95% confidence interval [CI]: 1.11–1.42, P ¼ 0.0002). Subtype analysis indicated that the association was primarily in the HTG subset (OR ¼ 1.26, 95% CI: 1.08–1.47, P ¼ 0.004). The risk allele T has been associated with elevated miR-182 expression in vitro. Data from ddPCR and miRNA-Seq confirmed miR-182 expression in all examined ocular tissues and TM-derived exosomes. Interestingly, miR-182 expression in AH was 2-fold higher in HTG patients than nonglaucoma controls (P ¼ 0.03) without controlling for medication treatment.
CONCLUSIONS. Our integrative study is the first to associate rs76481776 with POAG via elevated miR-182 expression
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