124 research outputs found
Classical Yang-Mills Black hole hair in anti-de Sitter space
The properties of hairy black holes in Einstein–Yang–Mills (EYM) theory are reviewed, focusing on spherically symmetric solutions. In particular, in asymptotically anti-de Sitter space (adS) stable black hole hair is known to exist for frak su(2) EYM. We review recent work in which it is shown that stable hair also exists in frak su(N) EYM for arbitrary N, so that there is no upper limit on how much stable hair a black hole in adS can possess
Comparison of single current dipole and Magnetic Field Tomography analyses of the cortical response to auditory stimuli
Atividades biológicas de espécies amazônicas de Rubiaceae
Rubiaceae is a plant family with great chemical and biological potential. In this work a phytochemical prospection was performed and it was assessed the cytotoxic, antioxidant and antifungal activities of dichloromethanic and methanolic extracts of the leaves of Duroia saccifera, Ferdinandusa goudotiana, F. hirsuta, F. paraensis, Ferdinandusa sp., Palicourea corymbifera and P. guianensis. The cytotoxicity evaluation was carried out using the test toxicity on Artemia salina. The antifungal activity was determined by agar diffusion method using fungi: Epidermophyton floccosum, Microsporum canis 32905, M. gipseum 29/00, Trichophyton mentagrophytes ATCC 9533/03, T. rubrum ATCC 28189, T. tonsurans 21/97, Cladosporium cladosporioides, C. sphaerospermum, Fusarium U. 662/06, Scytalidium U. 661/06, Candida albicans ATCC 3632 and C. albicans U. 5/99. The antioxidant activity was determined by testing the amount of free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the discoloration of the radical cation 6-sulfonic acid-2,2-azinobis-3-ethylbenzothiazoline (ABTS). For the toxicity test on A. salina greater toxicity in the methanol extract of F. goudotiana was observed, which proved to be toxic up to a concentration of 5 μg mL-1. The presence of antifungal principles was observed in the F. hirsuta and F. paraensis against four tested fungi. In the evaluation of the antioxidant activity, the methanol extracts showed greater activity than the dichloromethanic ones, being similar the obtained result through both methods (reduction of DDPH and ABTS decolorization). The results create possibilities for future researches related to the structure and activity of the components of each active extract. © 2015, Instituto de Biociencias. All rights reserved
Homogeneous cosmologies in generalized modified gravity
Dynamical system methods are used in the study of the stability of spatially
flat homogeneous cosmologies within a large class of generalized modified
gravity models in the presence of a relativistic matter-radiation fluid. The
present approach can be considered as the generalization of previous works in
which only cases were considered. Models described by an arbitrary
function of all possible geometric invariants are investigated and general
equations giving all critical points are derived.Comment: 13 pages, no figure
Effects of sleep deprivation on neural functioning: an integrative review
Sleep deprivation has a broad variety of effects on human performance and neural functioning that manifest themselves at different levels of description. On a macroscopic level, sleep deprivation mainly affects executive functions, especially in novel tasks. Macroscopic and mesoscopic effects of sleep deprivation on brain activity include reduced cortical responsiveness to incoming stimuli, reflecting reduced attention. On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity. In general, however, the relationships between the neural effects of sleep deprivation across observation scales are poorly understood and uncovering these relationships should be a primary target in future research
Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018
Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe
Mapping subnational HIV mortality in six Latin American countries with incomplete vital registration systems
BackgroundHuman immunodeficiency virus (HIV) remains a public health priority in Latin America. While the burden of HIV is historically concentrated in urban areas and high-risk groups, subnational estimates that cover multiple countries and years are missing. This paucity is partially due to incomplete vital registration (VR) systems and statistical challenges related to estimating mortality rates in areas with low numbers of HIV deaths. In this analysis, we address this gap and provide novel estimates of the HIV mortality rate and the number of HIV deaths by age group, sex, and municipality in Brazil, Colombia, Costa Rica, Ecuador, Guatemala, and Mexico.MethodsWe performed an ecological study using VR data ranging from 2000 to 2017, dependent on individual country data availability. We modeled HIV mortality using a Bayesian spatially explicit mixed-effects regression model that incorporates prior information on VR completeness. We calibrated our results to the Global Burden of Disease Study 2017.ResultsAll countries displayed over a 40-fold difference in HIV mortality between municipalities with the highest and lowest age-standardized HIV mortality rate in the last year of study for men, and over a 20-fold difference for women. Despite decreases in national HIV mortality in all countries-apart from Ecuador-across the period of study, we found broad variation in relative changes in HIV mortality at the municipality level and increasing relative inequality over time in all countries. In all six countries included in this analysis, 50% or more HIV deaths were concentrated in fewer than 10% of municipalities in the latest year of study. In addition, national age patterns reflected shifts in mortality to older age groups-the median age group among decedents ranged from 30 to 45years of age at the municipality level in Brazil, Colombia, and Mexico in 2017.ConclusionsOur subnational estimates of HIV mortality revealed significant spatial variation and diverging local trends in HIV mortality over time and by age. This analysis provides a framework for incorporating data and uncertainty from incomplete VR systems and can help guide more geographically precise public health intervention to support HIV-related care and reduce HIV-related deaths.Peer reviewe
The energy spectrum of cosmic rays beyond the turn-down around 10^17 eV as measured with the surface detector of the Pierre Auger Observatory
We present a measurement of the cosmic-ray spectrum above 100 PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750 m. An inflection of the spectrum is observed, confirming the presence of the so-called second-knee feature. The spectrum is then combined with that of the 1500 m array to produce a single measurement of the flux, linking this spectral feature with the three additional breaks at the highest energies. The combined spectrum, with an energy scale set calorimetrically via fluorescence telescopes and using a single detector type, results in the most statistically and systematically precise measurement of spectral breaks yet obtained. These measurements are critical for furthering our understanding of the highest energy cosmic rays
Efeito fitotóxico do óleo volátil de Cleome guianensis Aubl. sobre o crescimento inicial de Senna occidentalis L.
Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018
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