The bispectrum of redshifted 21-cm fluctuations from the dark ages

Brightness-temperature fluctuations in the redshifted 21-cm background from the cosmic dark ages are generated by irregularities in the gas-density distribution and can then be used to determine the statistical properties of density fluctuations in the early Universe. We first derive the most general expansion of brightness-temperature fluctuations up to second order in terms of all the possible sources of spatial fluctuations. We then focus on the three-point statistics and compute the angular bispectrum of brightness-temperature fluctuations generated prior to the epoch of hydrogen reionization. For simplicity, we neglect redshift-space distortions. We find that low-frequency radio experiments with arcmin angular resolution can easily detect non-Gaussianity produced by non-linear gravity with high signal-to-noise ratio. The bispectrum thus provides a unique test of the gravitational instability scenario for structure formation, and can be used to measure the cosmological parameters. Detecting the signature of primordial non-Gaussianity produced during or right after an inflationary period is more challenging but still possible. An ideal experiment limited by cosmic variance only and with an angular resolution of a few arcsec has the potential to detect primordial non-Gaussianity with a non-linearity parameter of f_NL ~ 1. Additional sources of error as weak lensing and an imperfect foreground subtraction could severely hamper the detection of primordial non-Gaussianity which will benefit from the use of optimal estimators combined with tomographic techniques.Comment: 15 pages, 4 figures, revised version accepted for publication in ApJ (contains an improved discussion of gas temperature fluctuations

Evidence of Hantavirus Infection among Bats in Brazil

Citation: Sabino-Santos, G., Maia, F. G. M., Vieira, T. M., Muylaert, R. D., Lima, S. M., Goncalves, C. B., . . . Figueiredo, L. T. M. (2015). Evidence of Hantavirus Infection among Bats in Brazil. American Journal of Tropical Medicine and Hygiene, 93(2), 404-406. doi:10.4269/ajtmh.15-0032Hantaviruses are zoonotic viruses harbored by rodents, bats, and shrews. At present, only rodent-borne hantaviruses are associated with severe illness in humans. New species of hantaviruses have been recently identified in bats and shrews greatly expanding the potential reservoirs and ranges of these viruses. Brazil has one of the highest incidences of hantavirus cardiopulmonary syndrome in South America, hence it is critical to know what is the prevalence of hantaviruses in Brazil. Although much is known about rodent reservoirs, little is known regarding bats. We captured 270 bats from February 2012 to April 2014. Serum was screened for the presence of antibodies against a recombinant nucleoprotein (rN) of Araraquara virus (ARAQV). The prevalence of antibody to hantavirus was 9/53 with an overall seroprevalence of 17%. Previous studies have shown only insectivorous bats to harbor hantavirus; however, in our study, of the nine seropositive bats, five were frugivorous, one was carnivorous, and three were sanguivorous phyllostomid bats

AVALIAÇÃO DA REUTILIZAÇÃO DE IMPLANTES DE PROGESTERONA SOBRE A TAXA DE PRENHEZ DE RECEPTORAS INOVULADAS COM EMBRIÕES IN VITRO

Atualmente, biotecnologias são empregadas na forma de protocolos a fim de sincronizar o crescimento folicular e a ovulação, bem como permitir que vacas atuem como receptoras de embriões visando melhorar o potencial genético do rebanho. O objetivo desse estudo foi avaliar o efeito da utilização de implantes intravaginais de progesterona de 1º, 2º e 3º uso no protocolo de transferência de embriões em tempo fixo (TETF) sobre a taxa de prenhez em receptoras girolandas. O experimento ocorreu em uma fazenda localizada no município de São Sebastião do Maranhão (MG). Foram utilizadas 74 vacas submetidas aos seguintes protocolos: No dia 0 (D0) administrou-se 2 ml de 17β-Estradiol e progesterona e foi colocado o implante intravaginal de progesterona. Estes implantes foram colocados de forma aleatória, sendo de 1° uso (grupo 1; n=15), 2° (grupo 2; n=24) ou 3° (grupo 3; n=35).No D8, os implantes foram retirados e administrou-se 2 ml PGF2α; 1,5 ml de eCG e 1 ml de 17β-Estradiol e progesterona. A inovulação dos embriões in vitroo correu no D (16) para todas as vacas que apresentaram um corpo lúteo. As variáveis qualitativas (prenhe ou não prenhe) foram comparadas em tabelas de contingência e analisadas pelo teste de qui-quadrado a 5% de probabilidade. Neste estudo não houve diferença estatística entre os grupos protocolados em relação ao aproveitamento como receptoras: 1º uso (53,3%), 2º (79,2%) e 3º (68,65). Ademais, observou-se uma taxa de prenhez entre os grupos de 37,5% para o 1º uso, 42,1% para o 2º e 33,3% para o 3º (P\u3e0,05). Dentre as vantagens ao reaproveitamento dos implantes multiusos destaca-se a redução dos custos dos protocolos hormonais, já que a progesterona é o hormônio mais oneroso, desta forma, a maximização do uso reduz o valor final do protocolo sem prejuízos a taxa de prenhez

Perturbations of spacetime: gauge transformations and gauge invariance at second order and beyond

We consider in detail the problem of gauge dependence that exists in relativistic perturbation theory, going beyond the linear approximation and treating second and higher order perturbations. We first derive some mathematical results concerning the Taylor expansion of tensor fields under the action of one-parameter families (not necessarily groups) of diffeomorphisms. Second, we define gauge invariance to an arbitrary order $n$. Finally, we give a generating formula for the gauge transformation to an arbitrary order and explicit rules to second and third order. This formalism can be used in any field of applied general relativity, such as cosmological and black hole perturbations, as well as in other spacetime theories. As a specific example, we consider here second order perturbations in cosmology, assuming a flat Robertson-Walker background, giving explicit second order transformations between the synchronous and the Poisson (generalized longitudinal) gauges.Comment: slightly revised version, accepted for publication in Classical and Quantum Gravity. 27 pages including 4 figures, latex using 2 CQG style files: ioplppt.sty, iopl10.st

Constraining Primordial Non-Gaussianity with High-Redshift Probes

We present an analysis of the constraints on the amplitude of primordial non-Gaussianity of local type described by the dimensionless parameter $f_{\rm NL}$. These constraints are set by the auto-correlation functions (ACFs) of two large scale structure probes, the radio sources from NRAO VLA Sky Survey (NVSS) and the quasar catalogue of Sloan Digital Sky Survey Release Six (SDSS DR6 QSOs), as well as by their cross-correlation functions (CCFs) with the cosmic microwave background (CMB) temperature map (Integrated Sachs-Wolfe effect). Several systematic effects that may affect the observational estimates of the ACFs and of the CCFs are investigated and conservatively accounted for. Our approach exploits the large-scale scale-dependence of the non-Gaussian halo bias. The derived constraints on {$f_{\rm NL}$} coming from the NVSS CCF and from the QSO ACF and CCF are weaker than those previously obtained from the NVSS ACF, but still consistent with them. Finally, we obtain the constraints on $f_{\rm NL}=53\pm25$ ($1\,\sigma$) and $f_{\rm NL}=58\pm24$ ($1\,\sigma$) from NVSS data and SDSS DR6 QSO data, respectively.Comment: 16 pages, 8 figures, 1 table, Accepted for publication on JCA

Accessible technologies for kinetic and kinematic analysis of people with disabilities: a literature review/ Tecnologias acessíveis para análise cinética e cinemática da pessoa com deficiência: uma revisão da literatura

Locomotion is the process by which a being moves from one place to another, including stopping, changing speed, changes in direction and adaptation to changes in terrain. Human walking follows a pattern, and it is one of the forms of locomotion that most calls the attention of researchers. Its variation among a group may indicate pathological conditions that influence the treatment and rehabilitation of patients with low mobility. The objective of this article is to carry out a review for the development of a low-cost instrumented treadmill that can assist in the rehabilitation, treatment and follow-up of patients with stroke, and for that, a search of articles related to the topic was carried out in databases such as ScienceDirect, PubMed and others. The results obtained were satisfactory and enabled the creation of a good database. It was possible to conclude that there is a diversity of existing resources and that it is up to the professionals to direct their choice to the one that suits them best

Diet and primary prevention of stroke: Systematic review and dietary recommendations by the ad hoc Working Group of the Italian Society of Human Nutrition

Abstract Background and aims To systematically review the latest evidence on established and emerging nutrition-related risk factors for incidence of and mortality from total, ischemic and haemorrhagic strokes. The present review was conducted in the framework of the work carried out through 2015 and 2016 for the preparation of the Italian Guidelines for the Prevention and Treatment of Stroke, 8th Edition, by ISO-SPREAD (Italian Stroke Organization and the Stroke Prevention and Educational Awareness Diffusion). Methods and results Systematic review of articles focused on primary prevention of stroke published between January 2013 to May 2016 through an extensive search of the literature using MEDLINE/PUBMED, EMBASE and the Cochrane Library. Articles were ranked according to the SIGN methodology while the GRADE system was used to establish the strength of recommendations. As a result of our literature search, we examined 87 meta-analyses overall (mainly of prospective studies), a few isolated more recent prospective studies not included in the meta-analyses, and a smaller number of available randomized controlled trials and case–control studies. Based on the analysis of the above articles, 36 Syntheses of the available evidence and 36 Recommendations were eventually prepared. The present document was developed by organizing the available evidence into three individual areas (nutrients, food groups and dietary patterns) to provide a systematic and user-friendly overview of the available evidence on the relationship between nutrition and primary prevention of stroke. Yet analysis of foods and food patterns allowed translating the information about nutrients in a tool more amenable to use in daily life also in the light of the argument that people eat foods rather than nutrients. Conclusions The present literature review and dietary recommendations provide healthcare professionals and all interested readers with a useful overview for the reduction of the risk of total, ischemic and haemorrhagic stroke through dietary modifications