Ocorrência dos genótipos g e p de rotavírus do grupo a em bezerros de rebanhos de corte no estado de São Paulo, Brasil.

Foi determinada a ocorrência de rotavírus do grupo A e a caracterização molecular G e P de estirpes detectadas em bezerros de rebanhos de corte em propriedades rurais do Estado de São Paulo, Brasil. Foram analisadas amostras de fezes de 649 bezerros de 14 rebanhos de corte com idade entre 1 e 60 dias, independentemente da manifestação clínica de diarréia, colhidas de julho de 2003 a julho de 2004. Por meio das técnicas de ELISA e de eletroforese em gel de poliacrilamida (PAGE), determinou-se a ocorrência de rotavírus do grupo A em 64,3% (09/14) dos rebanhos e em 6,2% (40/649) dos animais. A maior freqüência de infecção foi detectada em animais com idade entre 16 e 30 dias (10,5%). Foram diagnosticados bezerros infectados por rotavírus tanto em animais com sinais clínicos de diarréia (25,8%; 22/85) quanto naqueles assintomáticos (3,2%; 18/ 564), existindo, porém, uma correlação entre a presença da infecção e a manifestação clínica da diarréia (p < 0,01). A análise do perfil do genoma do rotavírus por PAGE identificou sete eletroferótipos distintos, indicando grande diversidade genômica dos rotavírus na região estudada. A genotipagem pela reação em cadeia da polimerase (RT-PCR) das amostras de rotavírus revelou que as estirpes circulantes nos rebanhos eram G6P[5], G6P[11], G6P[5]P[11] e G10P[11]

ArF excimer laser-enhanced photochemical vapor deposition of epitaxial Si from Si<SUB>2</SUB>H<SUB>6</SUB>: a simple growth kinetic model

Photolysis of Si2H6 using 193 nm radiation from an ArF excimer laser has been used to deposit homoepitaxial Si films in the temperature range of 250 to 350&#176;C. Photolytic decomposition of Si2H6 generates growth precursors which adsorb on to a hydrogenated Si surface. A growth kinetic model is proposed based on single-photon 193 nm absorption by Si2H6, and chemical reaction of the photofragments as they diffuse to the sub-strate surface. With the laser beam positioned parallel to the Si substrate, the deposi-tion yield of solid Si from photo-excited Si2H6 is estimated to be 0.20 &#177; 0.04. Growth rates vary linearly with laser intensity and Si2H6 partial pressure over a range of 1-15 mJ/cm2. pulse and 5-40 mTorr, respectively, and epitaxial films are deposited when laser intensity and Si2H6 partial pressure conditions are such that the initial photofragment concentration is less than ~1013 cm-3

Multimodal mate choice: exploring the effects of sight, sound, and scent on partner choice in a speed-date paradigm

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Territorial Tactics: The Socio-spatial Significance of Private Policing Strategies in Cape Town

This paper analyses the policing strategies of private security companies operating in urban space. An existing literature has considered the variety of ways that territory becomes of fundamental importance in the work of public police forces. However, this paper examines territory in the context of private security companies. Drawing on empirical research in Cape Town, it examines how demarcated territories become key subjects in private policing. Private security companies are responsible for a relatively small section of the city, while in contrast the public police ultimately have to see city space as a whole. Hence, private policing strategy becomes one of displacement, especially of so-called undesirables yielding a patchworked public space associated with private enclaves of consumption. The conclusions signal the historical resonances and comparative implications of these political-legal-security dynamics. © 2013 Urban Studies Journal Limited

Conditions determining the morphology and nanoscale magnetism of Co nanoparticles: Experimental and numerical studies

Co-based nanostructures ranging from core-shell to hollow nanoparticles were produced by varying the reaction time and the chemical environment during the thermal decomposition of Co2(CO)8. Both structural characterization and kinetic model simulation illustrate that the diffusivities of Co and oxygen determine the growth ratio and the final morphology of the nanoparticles. Exchange coupling between Co and Co-oxide in core/shell nanoparticles induced a shift of field-cooled hysteresis loops that is proportional to the shell thickness, as verified by numerical studies. The increased nanocomplexity when going from core/shell to hollow particles, also leads to the appearance of hysteresis above 300 K due to an enhancement of the surface anisotropy resulting from the additional spin-disordered surfaces.Comment: 29 pages including 11 figures embedded. Submitted to Phys. Rev.

Detecção de anticorpos heterólogos contra o vírus da leucose enzoótica bovina em caprinos.

O presente estudo foi idealizado com o intuito de investigar a possibilidade da transmissão do vírus da leucose enzoótica bovina (VLB) para cabritos recém-nascidos amamentados com colostro de vacas soropositivas para leucose enzoótica bovina (LEB). Para tanto, foram utilizados 31 caprinos que foram separados das mães logo após o nascimento, para em seguida receber colostro proveniente de 11vacas testadas sorologicamente para LEB. Amostras de soro sangüí neo dos caprinos foram colhidas ao 3, 45, 80,120 e 160 dias de idade e, depois, quando tinham aproximadamente 4 anos. Então, foram feitas as análises laboratoriais por meio do teste da imunodifusão em gel de ágar (IDGA) utilizando o antígeno gp51 para diagnóstico da LEB. Desse modo, constatou-se que uma parte dos cabritos que receberam colostro de vacas soropositivas para LEB estavam reagentes aos 3 dias de idade e negativos nas outras idades. Entretanto, todos os outros que receberam colostro de vacas soro negativas não reagiram nos testes sorológicos. Esses resultados permitiriam supor então que os anticorpos detectados eram de origem colostral. Após o declínio da imunidade passiva e na vida adulta, nenhum caprino soroconverteu. Portanto, pôde-se concluir que o colostro de vacas soropositivas para LEB não foi considerado um meio eficiente para a transmissão do VLB

Magnetic control of large room-temperature polarization

Numerous authors have referred to room-temperature magnetic switching of large electric polarizations as The Holy Grail of magnetoelectricity.We report this long-sought effect using a new physical process of coupling between magnetic and ferroelectric relaxor nano-regions. Here we report magnetic switching between the normal ferroelectric state and the ferroelectric relaxor state. This gives both a new room-temperature, single-phase, multiferroic magnetoelectric, PbZr0.46Ti0.34Fe0.13W0.07O3, with polarization, loss (<4%), and resistivity (typically 108 -109 ohm.cm) equal to or superior to BiFeO3, and also a new and very large magnetoelectric effect: switching not from +Pr to negative Pr with applied H, but from Pr to zero with applied H of less than a Tesla. This switching of the polarization occurs not because of a conventional magnetically induced phase transition, but because of dynamic effects: Increasing H lengthens the relaxation time by x500 from 100 ?s, and it couples strongly the polarization relaxation and spin relaxations. The diverging polarization relaxation time accurately fits a modified Vogel-Fulcher Equation in which the freezing temperature Tf is replaced by a critical freezing field Hf that is 0.92 positive/negative 0.07 Tesla. This field dependence and the critical field Hc are derived analytically from the spherical random bond random field (SRBRF) model with no adjustable parameters and an E2H2 coupling. This device permits 3-state logic (+Pr,0,negative Pr) and a condenser with >5000% magnetic field change in its capacitance.Comment: 20 pages, 5 figure

Materials with Colossal Dielectric Constant: Do They Exist?

Experimental evidence is provided that colossal dielectric constants, epsilon >= 1000, sometimes reported to exist in a broad temperature range, can often be explained by Maxwell-Wagner type contributions of depletion layers at the interface between sample and contacts, or at grain boundaries. We demonstrate this on a variety of different materials. We speculate that the largest intrinsic dielectric constant observed so far in non-ferroelectric materials is of order 100.Comment: 3 figure