848 resultados para History of Concepts. Science
Resumo:
Although dogs are considered to be the principal transmitter of rabies in Brazil, dog rabies had never been recorded in South America before European colonization. In order to investigate the evolutionary history of dog rabies virus (RABV) in Brazil, we performed a phylogenetic analysis of carnivore RABV isolates from around the world and estimated the divergence times for dog RABV in Brazil. Our estimate for the time of introduction of dog RABV into Brazil was the late-19th to early-20th century, which was later than the colonization period but corresponded to a period of increased immigration from Europe to Brazil. In addition, dog RABVs appeared to have spread to indigenous animals in Brazil during the latter half of the 20th century, when the development and urbanization of Brazil occurred. These results suggest that the movement of rabid dogs, along with human activities since the 19th century, promoted the introduction and expansion of dog RABV in Brazil.
Resumo:
Histological studies of ischaemic liver injury performed between 1962 and 1964 distinguished two types of cell death: classical necrosis, and a process involving conversion of scattered cells into small round masses of cytoplasm that often contained specks of condensed nuclear chromatin. Enzyme histochemistry demonstrated rupture of lysosomes in the former, but preservation of lysosomes in the latter. Similar small round masses were also observed sparsely in normal liver. Electron microscopy showed that the small round bodies resulted from cellular condensation and budding, that they were bounded by membranes and contained intact organelles, and that they were phagocytosed and digested by resident tissue cells, including epithelial cells. In work done in association with Jeffrey Searle, the process was found to occur spontaneously in a variety of malignant tumours and to be enhanced in squamous cell carcinomas of skin responding to radiotherapy. During 1971-1972, I collaborated with Andrew Wyllie and Alastair Currie while on sabbatical leave in Scotland. The newly defined type of cell death was shown to be regulated by hormones in the adrenal cortex and in breast carcinomas. Further, review of published electron micrographs of the cell death known to play an essential role in normal development revealed the same morphological pattern. We proposed that this distinctive phenomenon subserves a general homoeostatic function and suggested it be called apoptosis. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
Resumo:
This survey intends to report some of the major documents and events in the area of fractional calculus that took place since 1974 up to the present date.
Resumo:
Sertraline is widely prescribed worldwide and frequently detected in aquatic systems. There is, however, a remarkable gap of information on its potential impact on estuarine and coastal invertebrates. This study investigated sertraline accumulation and effects in Carcinus maenas. Crabs from a moderately contaminated (Lima) and a low-impacted (Minho) estuary were exposed to environmental and high levels of sertraline (0.05, 5, 500 μg L−1). A battery of biomarkers related to sertraline mode of action was employed to assess neurotransmission, energy metabolism, biotransformation and oxidative stress pathways. After a seven-day exposure, sertraline accumulation in crabs’ soft tissues was found in Lima (5 μg L−1: 15.3 ng L−1 ww; 500 μg L−1: 1010 ng L−1 ww) and Minho (500 μg L−1: 605 ng L−1 ww) animals. Lima crabs were also more sensitive to sertraline than those from Minho, exhibiting decreased acetylcholinesterase activity, indicative of ventilatory and locomotory dysfunction, inhibition of anti-oxidant enzymes and increased oxidative damage at ≥0.05 μg L−1. The Integrated Biomarker Response (IBR) index indicated their low health status. In addition, Minho crabs showed non-monotonic responses of acetylcholinesterase suggestive of hormesis. The results pointed an influence of the exposure history on differential sensitivity to sertraline and the need to perform evaluations with site-specific ecological receptors to increase relevance of risk estimations when extrapolating from laboratory to field conditions.
Resumo:
This article aims to reconstruct the critical debate regarding the examination of the crisis in the disciplines of art history and criticism with a particular focus on the proposal formulated by U.S. theorists who contributed to October journal. The discrediting of many modernist critical methods, particularly that of Clement Greenberg – the formalist diktat – marked the birth of the journal and gave rise to proposals set forth by critics committed to a new approach. Their divergent positions, nonetheless, have contributed to undermining the traditional concepts of the autonomy of art and criticism. The proposals discussed over the course of publication were the result of a reappraisal of the disciplinary instruments of art history and criticism pursuant to the crucial cultural changes which took place in the 1980s.