The Australian race : its origin, languages, customs, place of landing in Australia and the routes by which it spread itself over the continent /

Mode of access: Internet.

Determinantes da remuneração do spread de certificados de recebíveis do agronegócio no mercado brasileiro

O objetivo deste trabalho é avaliar os fatores que afetam a determinação dos spreads nas operações de Certificado de Recebível do Agronegócio (CRA). Foram selecionadas na amostra todas as emissões registradas na ANBIMA entre os anos de 2012 e maio de 2016. Verificou-se que a remuneração desse título é influenciada principalmente pela presença de reforço de crédito/garantias, pelo setor originador dos recebíveis e pela companhia securitizadora. Em uma segunda análise mais detalhada e acrescentando as variáveis uma a uma de forma a testar a aderência do modelo, encontraram-se evidências de que o tamanho da emissão e o percentual de subordinação são importantes variáveis de controle na determinação do spread. Ao incluirmos a variável rating, esta passa a ser relevante e da mesma forma acontece com a garantia, demonstrando que o percentual de subordinação reduz o spread do título, mas quando se acrescenta garantia, ele deixa de ser significativo. O sinal da variável garantia é positivo e demonstra que se há a necessidade de incluir garantias na emissão, é porque provavelmente é essencial para que a emissão ocorra. Por fim, a variável securitizadora mostrou-se relevante, indicando que o investidor leva em consideração a qualidade da mesma para a precificação do título.

Influence of geomagnetic activity on the occurrence of midlatitude ionogram-recorded spread-F

Delayed spread-F occurrence as recorded by ionograms, following geomagnetic activity (GA) has been investigated using data from 88 stations located around the world. The spread-F occurrence is delayed progressively from one to three days, from subauroral to midlatitude regions. The equatorial latitudes show suppressed activity. An examination of daily spread-F occurrence values relative to the AE index reveals not only a main delay of one day, but also delays of two and three days. These delays involve principally GA occurring around 0600 hrs LT.

Rates of spread of marine pathogens

Epidemics of marine pathogens can spread at extremely rapid rates. For example, herpes virus spread through pilchard populations in Australia at a rate in excess of 10 000 km year(-1), and morbillivirus infections in seals and dolphins have spread at more than 3000 km year(-1). In terrestrial environments, only the epidemics of myxomatosis and calicivirus in Australian rabbits and West Nile Virus in birds in North America have rates of spread in excess of 1000 km year(-1). The rapid rates of spread of these epidemics has been attributed to flying insect vectors, but flying vectors have not been proposed for any marine pathogen. The most likely explanation for the relatively rapid spread of marine pathogens is the lack of barriers to dispersal in some parts of the ocean, and the potential for long-term survival of pathogens outside the host. These findings caution that pathogens may pose a particularly severe problem in the ocean. There is a need to develop epidemic models capable of generating these high rates of spread and obtain more estimates of disease spread rate.

Does the neuropathology of human patients with variant Creutzfeldt-Jakob disease reflect haematogenous spread of the disease?

To test the hypothesis that the distribution of the pathology in variant Creutzfeldt-Jakob disease (vCJD) represents haematogenous spread of the disease, we studied the spatial correlation between the vacuolation, prion protein (PrP) deposits, and the blood vessel profiles in the cerebral cortex, hippocampus, dentate gyrus, and cerebellum of 11 cases of the disease. In the majority of areas, there were no significant spatial correlations between either the vacuolation or the diffuse type of PrP deposit and the blood vessels. By contrast, a consistent pattern of spatial correlation was observed between the florid PrP deposits and blood vessels mainly in the cerebral cortex. The frequency of positive spatial correlations was similar in different anatomical areas of the cerebral cortex and in the upper compared with the lower laminae. Hence, with the exception of the florid deposits, the data do not demonstrate a spatial relationship between the pathological features of vCJD and blood vessels. The spatial correlation of the florid deposits and blood vessels may be attributable to factors associated with the blood vessels that promote the aggregation of PrP to form a condensed core rather than reflecting the haematogenous spread of the disease. © 2003 Elsevier Ireland Ltd. All rights reserved.

Does the neurodegeneration of Alzheimer’s disease spread between visual cortical regions B17 and B18 via the feedforward or feedback short cortico-cortical projections?

The laminar distribution of senile plaques (SP) and neurofibrillary tangles (NFT) was studied in areas B17 and B18 of the visual cortex in 18 cases of Alzheimer’s disease which varied in disease onset and duration. The objective was to test the hypothesis that SP and NFT could spread via either the feedforward or feedback short cortico-cortical projections. In area B17, the mean density of SP and NFT reached a maximum in lamina III and in laminae II and III respectively. In B18, mean SP density was maximal in laminae III and IV and NFT density in laminae II and III. No significant correlations were observed in any cortical lamina between the density of SP and patient age. However, the density of NFT in laminae III, IV and VI in B18 was negatively correlated with patient age. In addition, in B18, the density of SP in lamina II and lamina V was negatively correlated with disease duration and disease onset respectively. Although these results suggest that SP and NFT might spread between B17 and B18 via the feedforward short cortico-cortical projections, it is also possible that the longer cortico-cortical and cortico-subcortical connections may be involved.

Sparsely spread CDMA - A statistical mechanics-based analysis

Sparse code division multiple access (CDMA), a variation on the standard CDMA method in which the spreading (signature) matrix contains only a relatively small number of nonzero elements, is presented and analysed using methods of statistical physics. The analysis provides results on the performance of maximum likelihood decoding for sparse spreading codes in the large system limit. We present results for both cases of regular and irregular spreading matrices for the binary additive white Gaussian noise channel (BIAWGN) with a comparison to the canonical (dense) random spreading code. © 2007 IOP Publishing Ltd.

AIDS: structure, replication and spread of the AIDS virus

AIDS (Acquired Immune Deficiency Syndrome)was first, described as a new disease of humans in 1981. The origins of the disease are controversial. AIDS is caused by a retrovirus, a type of virus which rarely attacks human cells. The first virus of this type recorded in humans is reponsible for a type of leukaemia and was identified in 1978. AIDS is thus the third type of human retrovirus to be discovered and hence, is referred to as T-lymphotrophic virus III (HTLV-III). For viruses to replicate, they have to invade a host cell which in this case is a T4-lymphocyte, a type of white blood cell that regulates the immune system. The problems of the disease result directly from the death of these cells. As a consequence, the immune system is compromised leading to a number of opportunistic secondary infections and other disorders.

Impact of linear mode coupling on the group delay spread in few-mode fibers

We report an investigation on the group delay spread in few-mode fibers operating in the weak and strong linear coupling regimes, and for the first time, we study the transition region between them. A single expression linking the group delay spread to the fiber correlation length is validated for any coupling regime, considering 3 guided modes.