Boletim informativo NEPS
Universidade do Minho. Instituto de Ciências Sociais. Núcleo de Estudos de População e Sociedade
2001-11-01
Resultados de pesquisa
Foram encontrados 91 registos.
Os micoplasmas, organismos que integram a classe Mollicutis, constituem um vasto grupo de procariotas que se diferenciam das outras bactérias pelo seu pequeno tamanho celular, pela falta de parede celular e pelas dimensões reduzidas do seu genoma. Mycoplasma e Ureoplasma são os géneros com maior importância médica, com algumas das suas espécies envolvidas em pneumonias, infeções urinárias e artrites no Homem. A natural associação dos micoplasmas com os seus hospedeiros específicos e o estado do sistema imunológico dos mesmos constituem fatores importantes na disseminação e estabelecimento das micoplasmoses, tornando difícil a sua prevenção e controlo. Na identificação dos micoplasmas em cultura ou em amostras clínicas podem ser utlizados testes serológicos (imunofluorescência, fixação do complemento, imunoenzimáticos e moleculares
As bactérias são procariotas que pertencem ao domínio Bacteria e apresentam três formas básicas: esférica, cilíndrica e helicoidal. As células podem associar-se, formando arranjos característicos de alguns géneros bacterianos. A parede celular, além de conferir forma às bactérias, é responsável pela diferenciação entre bactérias Gram-positivo e Gram-negativo. Além disso, é um alvo preferencial para a atuação de alguns antibióticos.
As bactérias patogénicas para o Homem obtêm a sua energia pelo catabolismo de diferentes tipos de nutrientes. Esta energia é utilizada, por exemplo, para a mobilidade bacteriana e para a síntese de macromoléculas. O catabolismo dos açúcares (pentoses e hexoses) ocorre essencialmente através das vias de Embden-Meyerof-Parnas, das pentoses-fosfato e de Entner-Doudoroff. O NADH e o NADPH produzidos nestes proce...
We compare the magnetic field at the centre and the self-magnetic flux through a current-carrying circular loop, with those obtained for current-carrying polygons with the same perimeter. As the magnetic field diverges at the position of the wires, we compare the self-fluxes utilizing several regularization procedures. The calculation is best performed utilizing the vector potential, thus highlighting its usefulness in practical applications. Our analysis answers some of the intuition challenges students face when they encounter a related simple textbook example. These results can be applied directly to the determination of mutual inductances in a variety of situations.
Laser-assisted chemical vapour deposition (LCVD) has been extensively studied in the last two decades. A vast range of applications encompass various areas such as microelectronics, micromechanics, microelectromechanics and integrated optics, and a variety of metals, semiconductors and insulators have been grown by LCVD. In this article, we review briefly the LCVD process and present two case studies of thin film deposition related to laser thermal excitation (e.g., boron carbide) and non-thermal excitation (e.g., CrO(2)) of the gas phase.
We study a system of two RLC oscillators coupled through a variable mutual inductance. The system is interesting because it exhibits some peculiar features of coupled oscillators: (i) there are two natural frequencies; (ii) in general, the resonant frequencies do not coincide with the natural frequencies; (iii) the resonant frequencies of both oscillators differ; (iv) for certain choices of parameters, there is only one resonant frequency, instead of the two expected.
During the course of systemic infections, the liver is an organ which is frequently involved. The pathology of the human immunodeficiency virus with all its infections, opportunistic tumours and some parasitoses, such as amebiasis, kala-azar, hydatidosis, schistosomiasis and fascioliasis, evolve into hepatic compromise. This development is what we attempt to summarise.
Most of the patients with immunodeficiency virus infection (75%-85%) are coinfected with cytomegalovirus. It is estimated that cytomegalovirus disease develops in 45% of them, mainly those presenting low CD4 cell counts (< 100/mm3). Retinitis is the most common manifestation of reactivated cytomegalovirus disease (85%), followed by other extra ocular sites (central nervous system, lungs, gastrointestinal system, adrenal glands, etc.). The particularly high incidence of cytomegalovirus retinitis, the difficulties concerning its therapeutical approach and the relatively unsatisfactory results, justify this review, according to the new treatment options presented in recent literature.
Oxide based diluted magnetic semiconductor (DMS) materials have been a subject of increasing interest due to reports of room temperature ferromagnetism in several systems and their potential use in the development of spintronic devices. However, concerns on the stability of the magnetic properties of different DMS systems have been raised. Their magnetic moment is often unstable, vanishing with a characteristic decay time of weeks or months, which precludes the development of real applications.
This paper reports on the ferromagnetic properties of two-year-aged Ti1-xCoxO2-δ reduced anatase nanopowders with different Co contents (0.03≤x≤0.10). Aged samples retain rather high values of magnetization, remanence and coercivity which provide strong evidence for a quite preserved long-range ferromagnetic order. In what concern Co segregatio...
Chromia (Cr2O3) has been extensively explored for the purpose of developing widespread industrial applications, owing to the convergence of a variety of mechanical, physical and chemical properties in one single oxide material. Various methods have been used for large area synthesis of Cr2O3 films. However, for selective area growth and growth on thermally sensitive materials, laser-assisted chemical vapour deposition (LCVD) can be applied advantageously.
Here we report on the growth of single layers of pure Cr2O3 onto sapphire substrates at room temperature by low pressure photolytic LCVD, using UV laser radiation and Cr(CO)(6) as chromium precursor. The feasibility of the LCVD technique to access selective area deposition of chromia thin films is demonstrated. Best results were obtained for a laser fluence of 120 mJ cm(-2) and a ...
