40 research outputs found

    Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

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    During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly

    Experimental progress in positronium laser physics

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    Multi-trait genome-wide association study identifies new loci associated with optic disc parameters

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    A new avenue of mining published genome-wide association studies includes the joint analysis of related traits. The power of this approach depends on the genetic correlation of traits, which reflects the number of pleiotropic loci, i.e. genetic loci influencing multiple traits. Here, we applied new meta-analyses of optic nerve head (ONH) related traits implicated in primary open-angle glaucoma (POAG); intraocular pressure and central corneal thickness using Haplotype reference consortium imputations. We performed a multi-trait analysis of ONH parameters cup area, disc area and vertical cup-disc ratio. We uncover new variants; rs11158547 in PPP1R36-PLEKHG3 and rs1028727 near SERPINE3 at genome-wide significance that replicate in independent Asian cohorts imputed to 1000 Genomes. At this point, validation of these variants in POAG cohorts is hampered by the high degree of heterogeneity. Our results show that multi-trait analysis is a valid approach to identify novel pleiotropic variants for ONH

    Predictors of Holding Consumer and Mortgage Debt among Older Americans

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    Using data from the 2000 Health and Retirement Study (HRS), this study examined the probability of older Americans holding consumer and mortgage debt. The specific objectives of this study were to identify to what extent individuals aged 65 and over hold consumer or mortgage debt and to investigate factors that influence the probability of holding consumer or mortgage debt in old age. The results of logistic regression analysis indicated that older individuals who had larger households, had higher levels of education, were aged 65–74, were married, were Black, and were employed, were more likely to hold consumer or mortgage debt. This study concluded that holding one kind of debt is associated with probability of holding another kind of debt. Copyright Springer Science+Business Media, LLC 2007Aging, Consumer debts, Mortgages, Economic well-being,

    Metabolismo oxidativo de neutrófilos em ovelhas naturalmente infectadas por nematódeos gastrintestinais e correlação entre nível sérico de cortisol e carga parasitária Neutrophils oxidative metabolism in sheep naturally infected by gastrointestinal nematodes and correlation between serum level of cortisol and parasitary burden

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    Estudaram-se as relações entre o metabolismo oxidativo dos neutrófilos, os níveis séricos de cortisol e a carga parasitária estimada pela contagem de ovos por grama de fezes (OPG) no final da gestação, durante a lactação e após o desmame de ovelhas naturalmente infectadas por nematódeos gastrintestinais. Utilizaram-se 22 ovelhas da raça Suffolk, homogêneas quanto à idade (três a quatro anos), número de parições (terceira) e época de parição. O cortisol sérico foi determinado por radioimunoensaio e o metabolismo oxidativo dos neutrófilos pelo teste de redução do tetrazólio nitroazul (NBT). Os maiores valores de OPG foram observados na quinta semana de lactação, e as maiores taxas de cortisol e de redução do NBT ocorreram na quarta semana pós-desmame. Verificou-se correlação positiva (r = 0,52; P<0,05) entre a capacidade dos neutrófilos reduzirem o NBT e a concentração sérica de cortisol no período pré-parto. Próximo ao parto o metabolismo oxidativo dos neutrófilos diminuiu. Após o desmame a correlação entre o OPG e o teste de redução do NBT foi negativa (r = -0,39; P<0,01). A diminuição do OPG observada após o desmame coincidiu com o aumento da capacidade de os neutrófilos reduzirem o NBT, indicando que animais com melhor resposta imune pós-desmame possuem neutrófilos com metabolismo oxidativo maior e menor carga parasitária.<br>The relationships between neutrophils oxidative metabolism, cortisol serum levels and worm burden, estimated by fecal egg count (EPG), were studied in sheep naturally infected by gastrointestinal parasites at the end of pregnancy, during lactation, and after weaning. Twenty-two Suffolk sheep three to four year-old, of same parity and season of parturition were used. Serum cortisol was determined by radioimmunoassay and the neutrophils oxidative metabolism by the nitroblue tetrazolium (NBT) reduction test. The highest EPG values were observed on the fifth week of lactation while the highest rates of cortisol and reduction of NBT occurred on the fourth week after weaning. A positive correlation (r = 0.52; P<0.01) was observed between the neutrophils capacity to reduce the NBT and the serum cortisol concentration in the pre-parturition period. Otherwise, the neutrophils oxidative metabolism decreased near to the parturition. A negative correlation (r = -0.39; P<0.01) between EPG and NBT reduction test was observed after weaning, which was coincident with the increase in the neutrophils capacity to reduce NBT, indicating that animals showing better immune response after weaning have neutrophils with higher oxidative metabolism and lower worm burden
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