Transient Charging and Discharging of Spin-polarized Electrons in a Quantum Dot

We study spin-polarized transient transport in a quantum dot coupled to two ferromagnetic leads subjected to a rectangular bias voltage pulse. Time-dependent spin-resolved currents, occupations, spin accumulation, and tunneling magnetoresistance (TMR) are calculated using both nonequilibrium Green function and master equation techniques. Both parallel and antiparallel leads' magnetization alignments are analyzed. Our main findings are: a dynamical spin accumulation that changes sign in time, a short-lived pulse of spin polarized current in the emitter lead (but not in the collector lead), and a dynamical TMR that develops negative values in the transient regime. We also observe that the intra-dot Coulomb interaction can enhance even further the negative values of the TMR.Comment: 7 pages, 6 figures. Typos corrections corresponding to the published versio

Chronic meningococcemia

The spectrum of Neisseria meningitidis-associated clinical entities involves mild forms of disease, without neurological involvement or sepsis, and asymptomatic carrier states. Rarely, N. meningitidis bacteremia can be associated with a prolonged fever with or without arthritis, which we designate as chronic meningococcemia. Chronic meningococcemia is an uncommon entity, usually associated to serogroup B N. meningitidis. Diagnosis is frequently delayed as blood cultures collected outside febrile periods can be negative. We present a case of chronic meningococcemia in a 22-year-old woman with no relevant clinical background, presenting with fever, arthralgia and exanthem. Due to the potential for progression to more severe disease and the risk of N. meningitidis transmission and development of secondary cases, a high degree of clinical suspicion is required to ensure prompt recognition and adequate treatment. Our patient had a favorable outcome probably due to early recognition and adequate treatment, which is critical for the resolution of the disease without complications

Transanal total mesorectal excision with triangle rules: a road map to prevent injuries

[Extract] Transanal total mesorectal excision (TaTME) is presented as a promising new surgical technique for the approach to the distal rectum, providing the ability to perform a highquality resection, with technical advantages over the laparoscopic approach. However, the new surgical anatomy of the TaTME resection complicates surgical understanding and increases the risks of inadvertent injuries to important anatomic structures...info:eu-repo/semantics/publishedVersio

The Galactic O-Star Spectroscopic Survey (GOSSS). III. 142 additional O-type systems

This is the third installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R~2500 digital observations selected from the Galactic O-Star Catalog (GOSC). In this paper we present 142 additional stellar systems with O stars from both hemispheres, bringing the total of O-type systems published within the project to 590. Among the new objects there are 20 new O stars. We also identify 11 new double-lined spectroscopic binaries (SB2s), of which 6 are of O+O type and 5 of O+B type, and an additional new tripled-lined spectroscopic binary (SB3) of O+O+B type. We also revise some of the previous GOSSS classifications, present some egregious examples of stars erroneously classified as O-type in the past, introduce the use of luminosity class IV at spectral types O4-O5.5, and adapt the classification scheme to the work of Arias et al. (2016).Comment: Accepted for publication in ApJS. This version has minor corrections regarding typos and reference

Bovine embryos cultured in vitro in the presence of antioxidants: implications for blastocysts development, quality and cryotolerance.

(ISABR 2012)

Diagnóstico fitossanitário em sementes de cedro e tachi branco.

O trabalho objetivou diagnosticar fitopatógenos presentes em sementes de cedro vermelho (Cedrela odorata L.) e tachi branco (Sclerolobium paniculatum Vogel), espécies florestais nativas da Amazônia. A importância da patologia de sementes relaciona-se com a disseminação de doenças pelo fruto quando este é levado para beneficiamento e para evitar o apodrecimento das sementes, o que pode ocasionar perda pela presença de fitopatógenos nas mesmas. Os testes foram feitos com base nas Regras de Análise de Sementes (RAS) do Ministério da Agricultura, Pecuária e Abastecimento ? MAPA, pelo método de incubação em papel filtro ?Blotter Test?. Foram detectados os seguintes gêneros de fungos: Aspergillus sp., Penicillium spp. e Lasiodiplodia sp. em sementes de cedro e Penicillium spp. e Aspergillus sp. em tachi branco. As sementes de cedro apresentaram maiores níveis de incidência de fungos.PIBIC-2011