560 research outputs found
Black-Hole Mass and Growth Rate at High Redshift
We present new H and K bands spectroscopy of 15 high luminosity active
galactic nuclei (AGNs) at redshifts 2.3-3.4 obtained on Gemini South. We
combined the data with spectra of additional 29 high-luminosity sources to
obtain a sample with 10^{45.2}<\lambda L_{\lambda}(5100A)<10^{47.3} ergs/sec
and black hole (BH) mass range, using reverberation mapping relationships based
on the H_beta method, of 10^{8.8}-10^{10.7} M_sun. We do not find a correlation
of L/L_Edd with M_BH but find a correlation with \lambda L_{\lambda}(5100A)
which might be due to selection effects. The L/L_Edd distribution is broad and
covers the range ~0.07-1.6, similar to what is observed in lower redshift,
lower luminosity AGNs. We suggest that this consistently measured and
calibrated sample gives the best representation of L/L_Edd at those redshifts
and note potential discrepancies with recent theoretical and observational
studies. The lower accretion rates are not in accord with growth scenarios for
BHs at such redshifts and the growth times of many of the sources are longer
than the age of the universe at the corresponding epochs. This suggests earlier
episodes of faster growth at z>~3 for those sources. The use of the C IV method
gives considerably different results and a larger scatter; this method seems to
be a poor M_BH and L/L_Edd estimator at very high luminosity.Comment: 8 pages (emulateapj), 4 figures. Accepted for publication in Ap
Accuracy of a teleported trapped field state inside a single bimodal cavity
We propose a simplified scheme to teleport a superposition of coherent states
from one mode to another of the same bimodal lossy cavity. Based on current
experimental capabilities, we present a calculation of the fidelity that can be
achieved, demonstrating accurate teleportation if the mean photon number of
each mode is at most 1.5. Our scheme applies as well for teleportation of
coherent states from one mode of a cavity to another mode of a second cavity,
both cavities embedded in a common reservoir.Comment: 4 pages, 2 figures, in appreciation for publication in Physical
Review
Strong structure recovery for partially observed discrete Markov random fields on graphs
We propose a penalized pseudo-likelihood criterion to estimate the graph of
conditional dependencies in a discrete Markov random field that can be
partially observed. We prove the convergence of the estimator in the case of a
finite or countable infinite set of variables. In the finite case the
underlying graph can be recovered with probability one, while in the countable
infinite case we can recover any finite sub-graph with probability one, by
allowing the candidate neighborhoods to grow with the sample size n and
provided the penalizing constant is sufficiently large. Our method requires
minimal assumptions on the probability distribution and contrary to other
approaches in the literature, the usual positivity condition is not needed. We
evaluate the performance of the estimator on simulated data and we apply the
methodology to a real dataset of stock index markets in different countries
Sex Determination of Pohnpei Micronesian Kingfishers Using Morphological and Molecular Genetic Techniques
Conservation-oriented studies of Micronesian Kingfishers (Todiramphus cinnamominus) have been hindered by a lack of basic natural history information, despite the status of the Guam subspecies (T. c. cinnamominus) as one of the most endangered species in the world. We used tissue samples and morphometric measures from museum specimens and wild-captured Pohnpei Micronesian Kingfishers (T. c. reichenbachii) to develop methods for sex determination. We present a modified molecular protocol and a discriminant function that yields the probability that a particular individual is male or female. Our results revealed that females were significantly larger than males, and the discriminant function correctly predicted sex in 73% (30/41) of the individuals. The sex of 86% (18/21) of individuals was correctly assigned when a moderate reliability threshold was set. Sex determination using molecular genetic techniques was more reliable than methods based on morphology. Our results will facilitate recovery efforts for the critically endangered Guam Micronesian Kingfisher and provide a basis for sex determination in the 11 other endangered congeners in the Pacific Basin
La evolución de la propuesta de valor de Recursos Humanos y la medición de su impacto
Dentro de un entorno de cambio y transformación a nivel global, el área de Recursos Humanos ha
evolucionado en los últimos 20 años. Empujada por la importancia creciente del lugar que adquiere el
Capital Humano, sin embargo, no siempre es considerada como un área que aporte valor a la gestión de
las personas en el marco del negocio. En muchas empresas hoy, aún no se sienta en la mesa de la toma
de decisiones.
En este trabajo se busca como objetivo principal, describir la evolución del área de Recursos Humanos,
comprender cuál es su situación actual e identificar aquellas nuevas capacidades que debiera adquirir
para lograr obtener un mayor posicionamiento estratégico y dejar de ser un área meramente transaccional.
A partir de una investigación empírica con un enfoque cualitativo descriptivo, de la situación actual, se
corrobora que la percepción del área como socio estratégico del negocio, lo cual daría cuenta de su grado
de posicionamiento, aún requiere de un gran recorrido. Siendo como uno de los principales desafíos la
transformación del departamento hacia una gestión ágil, acompañando su propuesta de valor a
compañías que también transitan hacia la agilidad. Es claro que si bien ha habido una evolución concreta
en el área de recursos humanos, sus progresos son más lentos que los cambios que ocurren en las
empresas
Viral hepatitis and the immunological response: a review
Introduction: In Brazil, viral hepatitis is infectious disease of compulsory notification and is considered a serious public health problem. Infections with A, B, C, D or E viruses trigger the activation of immune system molecules and cells at the level of innate and acquired immunity. Objective: The present study aimed to review the knowledge about viral hepatitis and the immune system's performance against these infections. Methods: This is a literature overview from academic books and scientific articles available in the Scientific Electronic Library Online, US National Library of Medicine National Institutes of Health and Google Scholar databases. Having as key words hepatitis A, hepatitis B, hepatitis C, hepatitis D, hepatitis E and immune system. The relevant articles corresponding to the period between 1974 and 2017 were selected. Development: Viral hepatitis is characterized by inflammation in liver cells caused by groups of viruses that have hepatotropism in common. The diagnosis is made through serological methods and molecular biology techniques. The approach of the immune system in relation to the combat of this infection follows same particularities. Conclusion: This review demonstrated that the determination of the etiologic agent is essential for the conduct to be taken with the infected individual. Moreover, the immune system is directed related to the viruses elimination, presenting some particularities. In addition, this review highlights that the vaccination is the main responsible for reducing people infected by viruses A and B
Isolamento e caracterização de cepas de Saccharomyces cerevisiae de interesse em produção de vinho
Despite the availability of several Saccharomyces cerevisiae commercial strains intended for wine production, strains isolated from winery regions are usually more adapted to their own climatic conditions, grapes and also partially responsible for particular characteristics that frequently identify specific wines and regions. Thus the microbiota of an important winery region (Colombo) was studied in order to isolate and characterize S. cerevisiae strains that could be used on wine production. From 61 yeasts isolated, 14 were identified as S. cerevisiae. Some of them showed fermentative characteristics even better than commercial strains indicating that they could be applied on wine production in order to increase the quality and assure the particular wine characteristics of that region
Estimativa de risco devido à ingestão de isótopos de urânio em fontes de águas minerais
OBJETIVOS: Complementar dados de investigação anterior sobre o risco de indução de câncer devido à ingestão de 226Ra, 228Ra e 222Rn em fontes de águas minerais de uma região de altos níveis de radioatividade natural, do Brasil. Desta forma, foi realizada a estimativa de indução de câncer devido à ingestão de 238U e 234U nessas mesmas águas. MÉTODO: O coeficiente de risco para os isótopos naturais de urânio foi considerado como sendo o mesmo daquele utilizado para a indução de sarcoma ósseo pelo 226Ra e que a quantidade depositada no osso corresponde a 25 vezes a ingestão diária de 226Ra e a 11 vezes a ingestão diária dos isótopos de urânio de meia-vida longa. Amostras de água das fontes ultilizadas pela população de Água da Prata, Estado de São Paulo, foram coletadas, num período de um ano, de forma a abranger todas as estações. RESULTADOS: Foram encontradas concentrações variando de 2,0 a 28,4 mBq/L e de 4,7 a 143m Bq/L para 238U e 234U, respectivamente. Baseando-se nessas concentrações foi estimado o risco devido à ingestão dos isótopos de urânio: um total de 0,3 casos de câncer por 10(6) indivíduos expostos. Este dado indica que a ingestão crônica de urânio nas concentrações observadas nas fontes analisadas resultará em um acréscimo no número de casos de câncer fatais de 0,1 %. CONCLUSÕES: Se as incertezas na estimativa dos efeitos carcinogênicos forem levadas em consideração, pode-se concluir que praticamente nenhum caso de câncer ocorrerá devido à ingestão de urânio presente nas águas minerais analisadas.OBJETIVOS: Complementar dados de investigação anterior sobre o risco de indução de câncer devido à ingestão de 226Ra, 228Ra e 222Rn em fontes de águas minerais de uma região de altos níveis de radioatividade natural, do Brasil. Desta forma, foi realizada a estimativa de indução de câncer devido à ingestão de 238U e 234U nessas mesmas águas. MÉTODO: O coeficiente de risco para os isótopos naturais de urânio foi considerado como sendo o mesmo daquele utilizado para a indução de sarcoma ósseo pelo 226Ra e que a quantidade depositada no osso corresponde a 25 vezes a ingestão diária de 226Ra e a 11 vezes a ingestão diária dos isótopos de urânio de meia-vida longa. Amostras de água das fontes ultilizadas pela população de Água da Prata, Estado de São Paulo, foram coletadas, num período de um ano, de forma a abranger todas as estações. RESULTADOS: Foram encontradas concentrações variando de 2,0 a 28,4 mBq/L e de 4,7 a 143m Bq/L para 238U e 234U, respectivamente. Baseando-se nessas concentrações foi estimado o risco devido à ingestão dos isótopos de urânio: um total de 0,3 casos de câncer por 10(6) indivíduos expostos. Este dado indica que a ingestão crônica de urânio nas concentrações observadas nas fontes analisadas resultará em um acréscimo no número de casos de câncer fatais de 0,1 %. CONCLUSÕES: Se as incertezas na estimativa dos efeitos carcinogênicos forem levadas em consideração, pode-se concluir que praticamente nenhum caso de câncer ocorrerá devido à ingestão de urânio presente nas águas minerais analisadas
Elaboração da pesquisa bibliográfica
Elaboração da pesquisa bibliográfic
Frequency of interleukin-4 (IL-4) -589 gene polymorphism and vaginal concentrations of IL-4, nitric oxide, and mannose-binding lectin in women with recurrent vulvovaginal candidiasis
Background. A C→T substitution at position -589 in the interleukin-4 (IL-4) gene is associated with increased production of IL-4. Associations between this polymorphism and recurrent vulvovaginal candidiasis (RVVC), as well as vaginal concentrations of IL-4 and the anticandidal compounds nitric oxide (NO) and mannose binding lectin (MBL), were evaluated. Methods. Vaginal samples obtained by lavage from 42 women with RVVC during the acute stage of the disease and 43 control samples were assayed by enzyme-linked immunosorbent assay for IL-4 and NO metabolites. The -589 IL-4 gene polymorphism was detected by polymerase chain reaction and endonuclease digestion. Data were analyzed by Fisher's exact test, the nonparametric Mann-Whitney and Kruskal-Wallis tests, and Spearman rank correlation. P < .05 was considered significant. Results. Candida albicans was identified in 38 patients with RVVC; 3 others had infection due to Candida tropicalis, and 1 had infection due to Candida krusei. The IL-4 T,T genotype was detected in 59.5% of patients with RVVC and in 7.0% of control subjects (P < .0001). The frequency of IL-4*T was 76.2% in patients with RVVC and 23.3% in control subjects (P < .0001). The median concentration of vaginal IL-4 was elevated in patients with RVVC, compared with control subjects (P < .0001). Conversely, vaginal concentrations of NO metabolites (P = .02) and MBL (P < .0001) were reduced in patients with RVVC. There was a positive association between IL-4*T homozygosity and vaginal IL-4 levels (P < .0001) and negative associations between this genotype and vaginal NO (P = .01) and MBL (P < .0001) concentrations. Conclusions. Reduced vaginal levels of anticandidal factors in IL-4*T homozygotes may increase susceptibility to RVVC.Peer reviewe
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