How hole defects modify vortex dynamics in ferromagnetic nanodisks

Defects introduced in ferromagnetic nanodisks may deeply affect the structure and dynamics of stable vortex-like magnetization. Here, analytical techniques are used for studying, among other dynamical aspects, how a small cylindrical cavity modify the oscillatory modes of the vortex. For instance, we have realized that if the vortex is nucleated out from the hole its gyrotropic frequencies are shifted below. Modifications become even more pronounced when the vortex core is partially or completely captured by the hole. In these cases, the gyrovector can be partially or completely suppressed, so that the associated frequencies increase considerably, say, from some times to several powers. Possible relevance of our results for understanding other aspects of vortex dynamics in the presence of cavities and/or structural defects are also discussed.Comment: 9 pages, 4 page

Effect of nanosize BaZrO3 inclusions on vortex parameters in YBaCuO

We report on the field dependence of the microwave complex resistivity data in YBa$_2$Cu$_3$O$_{7-x}$/BaZrO$_3$ films grown by PLD at various BaZrO$_3$ content. The data, analyzed within a recently developed general framework for the mixed-state microwave response of superconductors, yield the field dependence of the fluxon parameters such as the vortex viscosity and the pinning constant. We find that pinning undergoes a change of regime when the BaZrO$_3$ content in the target increases from 2.5 mol.% to 5 mol.%. Simultaneously, the vortex viscosity becomes an increasing function of the applied magnetic field. We propose a scenario in which flux lines are pinned as bundles, and a crossover from dilute point pins to dense c-axis correlated defects takes place between 2.5 and 5 mol.% in the BZO concentration. Our data are inconsistent with vortices occupying mainly the BaZrO$_3$ sites at low fields, and suggest instead that vortices occupy both BaZrO$_3$ sites and interstitials in the YBa$_2$Cu$_3$O$_{7-x}$ matrix, even at low fields.Comment: Presented at EUCAS 2009, to be published in J. Phys.:Conf. Serie

Predicted defect induced vortex core switching in thin magnetic nanodisks

We investigate the influence of artificial defects (small holes) inserted into magnetic nanodisks on the vortex core dynamics. One and two holes (antidots) are considered. In general, the core falls into the hole but, in particular, we would like to remark an interesting phenomenon not yet observed, which is the vortex core switching induced by the vortex-hole interactions. It occurs for the case with only one hole and for very special conditions involving the hole size and position as well as the disk size. Any small deformation in the disk geometry such as the presence of a second antidot changes completely the vortex dynamics and the vortex core eventually falls into one of the defects. After trapped, the vortex center still oscillates with a very high frequency and small amplitude around the defect center.Comment: 11pages, Revtex format, 17 figure

Avaliação do sêmen fresco e pós-congelado de ovinos da raça Morada Nova na região semiárida do Nordeste.

Resumo: A criopreservação de sêmen permite o armazenamento de material genético por tempo indeterminado, transmitindo características desejáveis. Após o processo de congelação/descongelação ocorre uma redução da taxa de fertilidade relacionada, principalmente, aos danos causados às estruturas e propriedades bioquímicas da membrana dos espermatozóides, podendo comprometer os processos de capacitação espermática e a reação acrossomal. Em relação à espécie ovina e mais precisamente a raça Morada Nova pouco se encontra na literatura trabalhos relacionados aos efeitos do congelamento no sêmen desses animais. Foram utilizados quatro animais onde se coletou o sêmen semanalmente no período mais seco do ano (outubro e novembro/2008) com o objetivo de relacionar as avaliações do sêmen fresco e pós-congelamento de ovinos da raça Morada Nova durante a época mais seca do ano na região semi-árida do Nordeste brasileiro

Hospedeiros de Anastrepha striata Schiner (Diptera: Tephritidae) em cinco municípios do estado do Amapá.

Resumo 4

Proteínas do plasma seminal de ovinos da raça Morada Nova presentes no período de transição chuvoso-seco na região Norte do Estado do Ceará.

A identificação das proteínas é uma das principais alternativas para compreendermos as interações do plasma seminal com os espermatozóides. Em relação à espécie ovina e, mais precisamente a raça Morada Nova poucos trabalhos são encontrados na literatura relacionados a esses animais. Foram utilizados quatro animais em idade reprodutiva onde foi coletado o sêmen semanalmente, no período de transição chuvoso-seco, na região Norte do Estado do Ceará, referentes aos meses de julho e agosto/2009. Observou-se a presença de 20 e 19 bandas protéicas nos meses de julho e agosto/2009, com pesos moleculares variando de 22 a 115kDa e 20 a 98kDa, respectivamente. Foram identificadas as proteínas de peso 97, 79, 66, 55, 42, 29 e 22 kDa em todo o período estudado. Objetivou-se avaliar a variação protéica do plasma seminal presentes no período de transição chuvoso-seco em ovinos da raça Morada Nova. Abstract: The protein identification is an alternative in order to understand the seminal plasma and spermatozoid interaction. Concerning to ovine specie and specially the Morada Nova breed, are rare the works found in literature related to these animals. It were utilized four adults animals at reproductive aging where it was collected semen weekly during the transition rainy/dry period related to months of Juky and August, in the North region of Ceará State. It was observed the presence of 20 and 19 proteins bands on July and August with molecular weight varying from 22 to 115 and from 20 to 98 kDa, respectively. It were identified proteins with molecular weight of 97, 79, 66, 55, 42, 29 and 22 kDa along the period studied. Aimed to evaluate the variation of seminal plasma protein present in the transition period wetdry sheep Morada Nova

Household water security through stored rainwater and consumer acceptability: a case study of the Anuradhapura District

Rainwater harvesting has increased in popularity in Sri Lanka over the past two decades due to the number of water supply projects funded by the government and non-governmental organizations (NGOs). The stored rainwater can provide accessible, reliable, timely and adequate supplies of water to households but there are uncertainties as to safety, in terms of water quality, and consumer acceptability. A study was, therefore, conducted in the Anuradhapura District, in the dry zone, to assess consumer acceptability of stored rainwater for household purposes and to conduct rainwater quality tests in a laboratory. The majority of households in Anuradhapura meet their drinking water requirements from protected wells (59.6 %). Prior to the project, people greatly preferred open wells as a source of domestic water, followed by tubewells, because they believed that water in open wells is of good quality and drinkable. However, stored rainwater has become the priority source now, especially through roof rainwater harvesting (RRWH), which is used during the dry periods. The study revealed that more than 85 % of households use stored rainwater for drinking although some have concerns over the quality and only drink it after boiling. The easy accessibility of water and the assurance by the project team that it is of good quality are the main reasons that people are willing to drink it. The acceptability of stored rainwater for consumption was very high in water-scarce areas and with the increasing distance to the nearest and alternative sources of good-quality water. Of those who felt that they had adequate water, 84 % of the sample households found it adequate in the wet season but only 21 % in the dry season. Water quality analysis revealed that the chemical and physical quality of stored rainwater is within the acceptable range with respect to Sri Lankan Standards, SLS: 614, for potable water quality (SLIS 1983). Other domestic water sources exceeded standards for electrical conductivity, total alkalinity, hardness, ammonium nitrogen, fluorides and total iron. However, stored rainwater was of lower biological quality than other domestic water sources.Length: pp.87-97Domestic waterWater securityWater harvestingWater qualityRural areasCase studies