984 resultados para electrochemistry C-V


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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We report results from a search for gravitational waves produced by perturbed intermediate mass black holes ( IMBH) in data collected by LIGO and Virgo between 2005 and 2010. The search was sensitive to astrophysical sources that produced damped sinusoid gravitational wave signals, also known as ringdowns, with frequency 50 <= f(0)/Hz <= 2000 and decay timescale 0.0001 less than or similar to tau/s less than or similar to 0.1 characteristic of those produced in mergers of IMBH pairs. No significant gravitational wave candidate was detected. We report upper limits on the astrophysical coalescence rates of IMBHs with total binary mass 50 <= M/ M circle dot <= 450 and component mass ratios of either 1: 1 or 4: 1. For systems with total mass 100 <= M/M circle dot <= 150, we report a 90% confidence upper limit on the rate of binary IMBH mergers with nonspinning and equal mass components of 6.9 x 10(-8) Mpc(-3) yr(-1). We also report a rate upper limit for ringdown waveforms from perturbed IMBHs, radiating 1% of their mass as gravitational waves in the fundamental, l = m = 2, oscillation mode, that is nearly three orders of magnitude more stringent than previous results.

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In this paper we report on a search for short-duration gravitational wave bursts in the frequency range 64 Hz-1792 Hz associated with gamma-ray bursts (GRBs), using data from GEO 600 and one of the LIGO or Virgo detectors. We introduce the method of a linear search grid to analyze GRB events with large sky localization uncertainties, for example the localizations provided by the Fermi Gamma-ray Burst Monitor (GBM). Coherent searches for gravitational waves (GWs) can be computationally intensive when the GRB sky position is not well localized, due to the corrections required for the difference in arrival time between detectors. Using a linear search grid we are able to reduce the computational cost of the analysis by a factor of O(10) for GBM events. Furthermore, we demonstrate that our analysis pipeline can improve upon the sky localization of GRBs detected by the GBM, if a high-frequency GW signal is observed in coincidence. We use the method of the linear grid in a search for GWs associated with 129 GRBs observed satellite-based gamma-ray experiments between 2006 and 2011. The GRBs in our sample had not been previously analyzed for GW counterparts. A fraction of our GRB events are analyzed using data from GEO 600 while the detector was using squeezed-light states to improve its sensitivity; this is the first search for GWs using data from a squeezed-light interferometric observatory. We find no evidence for GW signals, either with any individual GRB in this sample or with the population as a whole. For each GRB we place lower bounds on the distance to the progenitor, under an assumption of a fixed GW emission energy of 10(-2)M circle dot c(2), with a median exclusion distance of 0.8 Mpc for emission at 500 Hz and 0.3 Mpc at 1 kHz. The reduced computational cost associated with a linear search grid will enable rapid searches for GWs associated with Fermi GBM events once the advanced LIGO and Virgo detectors begin operation.

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We present the results of a search for gravitational waves associated with 223 gamma-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M(circle dot)c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

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The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave (GW) astrophysics communities. The purpose of NINJA is to study the ability to detect GWs emitted from merging binary black holes (BBH) and recover their parameters with next-generation GW observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete BBH hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a 'blind injection challenge' similar to that conducted in recent Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo science runs, we added seven hybrid waveforms to two months of data recoloured to predictions of Advanced LIGO (aLIGO) and Advanced Virgo (AdV) sensitivity curves during their first observing runs. The resulting data was analysed by GW detection algorithms and 6 of the waveforms were recovered with false alarm rates smaller than 1 in a thousand years. Parameter-estimation algorithms were run on each of these waveforms to explore the ability to constrain the masses, component angular momenta and sky position of these waveforms. We find that the strong degeneracy between the mass ratio and the BHs' angular momenta will make it difficult to precisely estimate these parameters with aLIGO and AdV. We also perform a large-scale Monte Carlo study to assess the ability to recover each of the 60 hybrid waveforms with early aLIGO and AdV sensitivity curves. Our results predict that early aLIGO and AdV will have a volume-weighted average sensitive distance of 300 Mpc (1 Gpc) for 10M circle dot + 10M circle dot (50M circle dot + 50M circle dot) BBH coalescences. We demonstrate that neglecting the component angular momenta in the waveform models used in matched-filtering will result in a reduction in sensitivity for systems with large component angular momenta. This reduction is estimated to be up to similar to 15% for 50M circle dot + 50M circle dot BBH coalescences with almost maximal angular momenta aligned with the orbit when using early aLIGO and AdV sensitivity curves.

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With aging, naturally occurs the decline of several functions. The depression (DP), pointed to be a risk factor for cognitive decline (DC), is frequent amongst elders. Activities aimed at cognitive rehabilitation (RC) can be protective for DP and DC. Objectives: Analyze the association between DC and DP on institutionalized elders (IDI) and non-institutionalized elders (IDNI) and verify the protective function (regarding DP and DC) of RC activities. Design and Method: For the analysis were selected 48 elders, from both genders, from where 24 were institutionalized and 24 were not. The subjects were distributed in four subgroups: 1) IDI participating RC (n=12); 2) non participant IDI on RC (n=12); 3) IDNI participating UNATI (“Open College for the Elderly”) and attendees of Memory Workshop (MW) (n=12) and; 4) IDNI participating UNATI, not attending MW (n=12). The data were gathered from the instruments: Mini Mental State Exam (MEEM) to determine the degree of DC and Beck Depression Inventory (BDI) to verify the symptomatology of DP. Results: From the general sample, 8,3% of the subjects presented indicatives of DC and 52,1% traces of DP. Lesser educated elders showed more incidence of DC and DP. There was no meaningful related to the DC prevalence and DP related to gender. Among the IDI there were more incidence of DC and DP than the IDNI. There were no meaningful differences in terms of scores acquired by MEEM and BDI for the subjects participating and not participating RC activities or MW. Conclusion: Therefore, it is necessary the development and application of curative and preventive strategies for depressive disorder. Special attention must be given for INI, more vulnerable to DP and DC.

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O Autismo Infantil é um Transtorno Global do Desenvolvimento que se caracteriza pela presença de comprometimentos severos nas áreas de comunicação, interação social recíproca, interesses e comportamentos. Este trabalho teve como objetivos analisar o atendimento realizado com indivíduos autistas em uma instituição e verificar como a Terapia Ocupacional pode contribuir na atenção voltada aos alunos. A pesquisa foi realizada através da observação e registro em diário de campo das atividades realizadas por cinco indivíduos com Autismo em uma associação específica de Autismo e Transtornos no Desenvolvimento. Também foi realizada entrevista com os profissionais que atuam na instituição. No diário de campo, nota-se a prevalência das atividades pedagógicas. Por outro lado, observa-se escassez de atividades funcionais, de atividades básicas e instrumentais de vida diária, e de atividades direcionadas à comunicação e interação. Nas entrevistas, foi possível constatar que existe interesse dos profissionais na implantação do serviço de Terapia Ocupacional. Considerando as possibilidades de atuação da Terapia Ocupacional junto às crianças e jovens com autismo, conclui-se que a implantação desse setor nessa associação poderia trazer inúmeros benefícios para os usuários e equipe de profissionais da instituição.

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O presente trabalho propõe a análise da situação do idoso no contexto brasileiro, enfocando os idosos institucionalizados e as nuances do processo de institucionalização na saúde mental dos mesmos. Utilizou como metodologia a análise bibliográfica e observação participativa. Na discussão, o presente trabalho demonstra que a institucionalização tem efeitos danosos para o idoso em sua saúde mental, e a partir disto propõe uma perspectiva multidisciplinar do processo.

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A disfonia espasmódica é um distúrbio vocal grave, caracterizada por espasmos musculares laríngeos durante a fonação, produzindo voz tensa e estrangulada. Atualmente, acredita-se que tenha origem neurológica, mas há evidências que associam suas causas com alterações psicogênicas. O presente estudo visa descrever dois casos diagnosticados como disfonia espasmódica, com manifestações fonoaudiológicas e psicológicas distintas. O estudo descritivo foi realizado por meio de análise dos prontuários, incluindo avaliação otorrinolaringológica, neurológica, avaliação vocal perceptivo-auditiva, análise acústica e Protocolo de Qualidade de Vida e Voz (QVV). Caso 1: sexo feminino, 65 anos, discreta coaptação de bandas ventriculares, fenda fusiforme e intenso tremor laríngeo. Apresentou quadro de alucinação, diagnosticada, posteriormente, como Esquizofrenia. Faz uso de Risperidona e Pondera. Apresentou loudness rebaixado, pitch agravado, rouquidão, hipernasalidade leve, tempo máximo de fonação reduzido, incoordenação pneumofonoarticulátoria e G², R², Bº, Aº, S³. Caso 2: sexo feminino, 68 anos, alteração das pregas vocais e intenso estrangulamento de bandas ventriculares. Sofreu três acidentes vasculares encefálicos (AVE) e, após o primeiro, iniciou-se a rouquidão. Realiza atendimento psicológico, ainda sem diagnóstico fechado. Apresentou loudness rebaixado, pitch agudizado, diplofonia durante a conversação, tempo máximo de fonação reduzido, incoordenação pneumofonoarticulatória e G³, R², Bº, Aº, S³. Os dados demonstraram distintos graus de severidades nas manifestações otorrinolaringológicas e fonoaudiológicas, além de diferentes envolvimentos psicogênicos. O grau de severidade ficou implícito no impacto da voz na qualidade de vida das pacientes estudadas.

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We present an implementation of the F-statistic to carry out the first search in data from the Virgo laser interferometric gravitational wave detector for periodic gravitational waves from a priori unknown, isolated rotating neutron stars. We searched a frequency f(0) range from 100 Hz to 1 kHz and the frequency dependent spindown f(1) range from -1.6(f(0)/100 Hz) x 10(-9) Hz s(-1) to zero. A large part of this frequency-spindown space was unexplored by any of the all-sky searches published so far. Our method consisted of a coherent search over two-day periods using the F-statistic, followed by a search for coincidences among the candidates from the two-day segments. We have introduced a number of novel techniques and algorithms that allow the use of the fast Fourier transform (FFT) algorithm in the coherent part of the search resulting in a fifty-fold speed-up in computation of the F-statistic with respect to the algorithm used in the other pipelines. No significant gravitational wave signal was found. The sensitivity of the search was estimated by injecting signals into the data. In the most sensitive parts of the detector band more than 90% of signals would have been detected with dimensionless gravitational-wave amplitude greater than 5 x 10(-24).

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This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009-October 2010) and was sensitive to IMBHBs with a range up to similar to 200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M-circle dot and mass ratios between 0.25 and 1 were placed by combining this analysis with an analogous search performed on data from the first LIGO-Virgo joint science run (November 2005-October 2007). The most stringent limit was set for systems consisting of two 88 M-circle dot black holes and is equal to 0.12 Mpc(-3) Myr(-1) at the 90% confidence level. This paper also presents the first estimate, for the case of an unmodeled analysis, of the impact on the search range of IMBHB spin configurations: the visible volume for IMBHBs with nonspinning components is roughly doubled for a population of IMBHBs with spins aligned with the binary's orbital angular momentum and uniformly distributed in the dimensionless spin parameter up to 0.8, whereas an analogous population with antialigned spins decreases the visible volume by similar to 20%.