12,527 research outputs found
Anisotropic superconducting properties of aligned MgB2 crystallites
Samples of aligned MgB2 crystallites have been prepared, allowing for the
first time the direct identification of an upper critical field anisotropy
Hc2^{ab}/Hc2^{c}= xi_{ab}/xi_{c} ~ 1.73; with xi_{o,ab} ~ 70 A, xi_{o,c} ~ 40
A, and a mass anisotropy ratio m_{ab}/m_{c} ~ 0.3. A ferromagnetic background
signal was identified, possibly related to the raw materials purity.Comment: 4 pages, 4 figures; Revised version to appear in Phys. Rev. Let
Assessment of the executive functions of moderate preterm children in preschool age
This study assesses EF and socioemotional development in 30 MPT children between 4 and 6 years, comparing them with 31 FT children. Working Memory was assessed with Digit Span and Corsi Block, verbal inhibitory control and cognitive flexibility with The Shape School Test, visuomotor inhibition with Go/No-Go and socioemotional development with SDQ for parents. In our study, MPT preschoolers had a poorer working memory, inhibitory control and verbal cognitive flexibility, and more emotional problems compared. Our results suggest that there is no safe gestational age in prematurity, for this reason, EF of preterm children should be evaluated at an early age, so early intervention plans can be implemented, preventing preterm from entering primary education in disadvantage.info:eu-repo/semantics/acceptedVersio
Crescimento e qualidade química de frutos de Mangueira kent sob secamento parcial de raiz.
O objetivo deste trabalho foi avaliar o crescimento e a qualidade de frutos da mangueira ?Kent? sob secamento parcial de raiz (PRD) em condições do semiárido baiano. O estudo foi conduzido na área experimental em 0,48 ha da fazenda Boa Vista, no município de Iaçu, BA entre agosto e novembro de 2009 com 144 plantas. Os tratamentos com PRD foram baseados no percentual da lâmina bruta aplicada (LBA) pela fazenda, estimada pela evapotranspiração da cultura para irrigação localizada (ETc). O gotejamento foi o sistema de irrigação utilizado, com duas linhas laterais por fileira de plantas, entretanto, para a aplicação do PRD foi utilizada uma linha alternadamente com três emissores. O delineamento foi em blocos casualizados com três repetições, sendo oito tratamentos: T1, T2 e T3 (PRD 50% com alternância aos 7, 14 e 21 dias); T4, T5 e T6 (100% na fase de floração e 50% nas fases frutificação e estabilidade de frutos, com mesma ordem de alternância); T7 (50% fixo) e T8-testemunha (100% da LBA nos dois lados). Foram avaliados parâmetros físicos (taxa de pegamento e crescimento dos frutos) que não sofreram influência do PRD e químicos (sólidos solúveis e acidez total) que sob lâminas menores tiveram aumentos significantes
HIV-1 mother-to-child transmission in Brazil (1994\u20132016): a time series modeling
HIV-1 mother-to-child transmission (HIV-1 MTCT), is an important cause of children mortality worldwide. Brazil has been traditionally praised by its HIV/Aids program, which provides free-of-charge care for people living with HIV-1. Using public epidemiology and demographic databases, we aimed at modeling HIV-1 MTCT prevalence in Brazil through the years (1994\u20132016) and elaborate a statistical model for forecasting, contributing to HIV-1 epidemiologic surveillance and healthcare decision-making. We downloaded sets of live births and mothers\u2019 data alongside HIV-1 cases notification in children one year old or less. Through time series modeling, we estimated prevalence along the years in Brazil, and observed a remarkable decrease of HIV-1 MTCT between 1994 (10 cases per 100,000 live births) and 2016 (five cases per 100,000 live births), a reduction of 50%. Using our model, we elaborated a prognosis for each Brazilian state to help HIV-1 surveillance decision making, indicating which states are in theory in risk of experiencing a rise in HIV-1 MTCT prevalence. Ten states had good (37%), nine had mild (33%), and eight had poor prognostics (30%). Stratifying the prognostics by Brazilian region, we observed that the Northeast region had more states with poor prognosis, followed by North and Midwest, Southeast and South with one state of poor prognosis each. Brazil undoubtedly advanced in the fight against HIV-1 MTCT in the past two decades. We hope our model will help indicating where HIV-1 MTCT prevalence may rise in the future and support government decision makers regarding HIV-1 surveillance and prevention
Magnetic reconfiguration of MnAs/GaAs(001) observed by Magnetic Force Microscopy and Resonant Soft X-ray Scattering
We investigated the thermal evolution of the magnetic properties of MnAs
epitaxial films grown on GaAs(001) during the coexistence of
hexagonal/orthorhombic phases using polarized resonant (magnetic) soft X-ray
scattering and magnetic force microscopy. The results of the diffuse satellite
X-ray peaks were compared to those obtained by magnetic force microscopy and
suggest a reorientation of ferromagnetic terraces as temperature rises. By
measuring hysteresis loops at these peaks we show that this reorientation is
common to all ferromagnetic terraces. The reorientation is explained by a
simple model based on the shape anisotropy energy. Demagnetizing factors were
calculated for different configurations suggested by the magnetic images. We
noted that the magnetic moments flip from an in-plane mono-domain orientation
at lower temperatures to a three-domain out-of-plane configuration at higher
temperatures. The transition was observed when the ferromagnetic stripe width L
is equal to 2.9 times the film thickness d. This is in good agreement with the
expected theoretical value of L = 2.6d.Comment: 16 pages in PD
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