Browsing by Issue Date, starting with "2003"
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- Sociologia das organizações: sistemas de informação e desempenho profissionalPublication . Carreira, Teresa Pires; Sequeira, BernardeteEsta artigo assenta numa triologia conceptual dos domínios da sociologia do trabalho e das organizações.
- Contrasting portuguese and international service quality management in the Algarve hotel industryPublication . Cândido, CarlosThis paper establishes a contrast between the management of three different kinds of hotels operating in the Algarve: international chain hotels, portuguese chain hotels and independent hotels. The dimensions along which the contrast is established are fourteen service quality gaps (SQGs), taken from a model which has been developed in a previous paper by the author and a co-author (Cândido et al., 2000). Sample data has been collected through a questionnaire implemented in the population of four and five star hotels of the Algarve (FFSHA). Data analysis involves descriptive statistics and some statistical tests. In general, descriptives emphasise differences between the hotel groups and raise concerns about possible inconsistent management practices. The paper concludes with several specific suggestions to improve service quality in the FFSHA.
- Novel laser-induced luminescence resulting from benzophenone/O-propylated p-tert-butylcalix[4]arene complexes. A diffuse reflectance studyPublication . Ferreira, Luís F. Vieira; Ferreira, Margarida R. Vieira; Silva, José P. da; Machado, Isabel Ferreira; Oliveira, A. S.; Prata, José V.Laser-induced room temperature luminescence of air-equilibrated benzophenone/O-propylated p-tert-butylcalix[ 4] arene solid powdered samples revealed the existence of a novel emission, in contrast with benzophenone/p-tertbutylcalix[ 4] arene complexes, where only benzophenone emits. This novel emission was identified as phosphorescence of 1-phenyl-1,2-propanedione, which is formed as the result of an hydrogen atom abstraction reaction of the triplet excited benzophenone from the propoxy substituents of the calixarene. Room temperature phosphorescence was obtained in air-equilibrated samples in all propylated hosts. The decay times of the benzophenone emission vary greatly with the degree of propylation, the shortest lifetimes being obtained in the tri- and tetrapropylated calixarenes. Triplet - triplet absorption of benzophenone was detected in all cases, and is the predominant absorption in the p-tert-butylcalix[ 4] arene case, where an endo-calix complex is formed. Benzophenone ketyl radical formation occurs with the O-propylated p-tert-butylcalix[ 4] arenes hosts, suggesting a different type of host/guest molecular arrangement. Diffuse reflectance laser. ash photolysis and gas chromatography - mass spectrometry techniques provided complementary information, the former about transient species and the latter regarding the final products formed after light absorption. Product analysis and identification clearly show that the two main degradation photoproducts following laser excitation in the propylated substrates are 1-phenyl-1,2- propanedione and 2- hydroxybenzophenone, although several other minor photodegradation products were identified. A detailed mechanistic analysis is proposed. While the solution photochemistry of benzophenone is dominated by the hydrogen abstraction reaction from suitable hydrogen donors, in these solid powdered samples, the alpha-cleavage reaction also plays an important role. This finding occurs even with one single laser pulse which lasts only a few nanoseconds, and is apparently related to the fact that scattered radiation exists, due to multiple internal reflections possibly trapping light within non-absorbing microcrystals in the sample, and is detected until at least 20 mus after the laser pulse. This could explain how photoproducts thus formed could also be excited with only one laser pulse.
- Temperature and salinity regimes in a shallow, mesotidal lagoon, the Ria Formosa, PortugalPublication . Newton, Alice; Mudge, S.In a recent study of the mesotidal Ria Formosa, a coastal lagoon in southern Portugal, water temperature in the channels ranged from 12 C in winter to 27 C in summer and salinity from 13 to 36.5, although much higher values were observed in saltpans. Conditions in the Ria Formosa were not homogeneous despite a large tidal exchange of water; the inner channels of the Ria Formosa were brackish in winter but hypersaline in summer. Water in inner areas of lagoon had significantly different temperature and salinity characteristics compared to the inflowing coastal water, both in winter and in summer. Areas with these differences in temperature and salinity were detectable both at low water and at high water neaps. Deterioration of water quality is therefore more probable in these areas. The waters went through a complex heating and cooling cycle in summer with diurnal difference of 6 C and 2 in temperature and salinity, respectively. The lack of freshwater input and high insolation meant the outflowing water of the lagoon was more saline that the inflowing coastal waters. In summer, the temperature controlled density with the least dense waters also being the most saline, whereas in winter salinity was the major density controlling parameter. The effects of these freshwater inputs were localised to the vicinity of the Gila˜o River. No evidence was found of persistent or widespread temperature or salinity stratification in the Ria Formosa and so this shallow lagoon appears to be vertically well mixed. Vertical mixing does not allow a dense, stagnant, bottom layer of water to form that would aggravate a deterioration of water quality. The net effect of these processes is a parcel of water that moves through the lagoon with minimal dilution and potentially receiving waste discharges.
- Carlos Nogueira. O essencial sobre o cancioneiro narrativo tradicional, Lisboa, Imprensa Nacional - Casa da Moeda, 2003, 96 páginasPublication . Galhoz, Maria AlieteCarlos Nogueira é docente no Ensino Superior e jovem investigador institucional (C. T. P. P.) na área das “artes da fala” e da cultura popular e está perfeitamente vocacionado para poder intentar a abordagem que faz n’ O Essencial sobre o Cancioneiro Narrativo Tradicional. Sem dúvida, este estudo (e antologia), tal como no-lo propõe, partindo de propostas teóricas de ponta nos estudos literários, representa um percurso de pioneirismo hermenêutico em relação a este subgénero da poesia tradicional, percurso já substancialmente atentado com outros contributos, sistematizados, no campo da literatura tradicional popular.
- In vitro metabolism of pregnenolone to 7 alpha-hydroxypregnenolone by rainbow trout embryosPublication . Petkam, R.; Renaud, R. L.; Freitas, A. M. M. S.; Canario, Adelino V. M.; Raeside, J. I.; Kime, D. E.; Leatherland, J. F.Tissues taken from rainbow trout embryos at several developmental stages, were incubated in the presence of radioactively-labelled pregnenolone in order to determine the capability of salmonid embryos to metabolize steroids, such as pregnenolone, that are incorporated into the oocyte during gonadal growth and maturation. High performance liquid chromatography was used to separate the steroid products, and gas chromatography–mass spectrometry was applied for the chemical identification of the product. 7α-Hydroxypregnenolone, previously known to be produced only by ovarian tissues, was found to be the sole metabolite of pregnenolone metabolism by rainbow trout embryos. Sulfate and glucuronide conjugated forms of 7α-hydroxypregnenolone were also produced. We hypothesize that this metabolite provides a pathway for excretion of pregnenolone, enabling the embryo to maintain its own steroid milieu, although the possibility of 7α-hydroxypregnenolone also playing a physiological role cannot be excluded.
- Consequências do polimorfismo das ceras cuticulares para a função de barreira da cutícula vegetal: estudos em sistemas modeloPublication . Carreto, Laura Cristina da Silva; Vaz, WinchilMuito embora a especiação das plantas vasculares se tenha traduzido na evolução de uma larga variedade de cutículas, algumas das características que determinam a função desta membrana, encontrada a revestir as partes não lenhificadas das plantas, foram conservadas evolutivamente. Não se conhecem excepções à regra de que a cutícula vegetal é uma estrutura de dupla-face, composta por dois meios distintos tanto em composição como em estrutura molecular, ambos acessíveis à difusão de permeantes. São eles, uma matriz polimérica de cutina, concentrada no lado mais interno da cutícula, e as ceras cuticularcs, acumuladas junto da superfície externa.
- A estrutura de capital e o ciclo de vida das empresasPublication . Rebelo, Sandra; Matias, Maria Fernanda Ludovina InácioEste estudo pretende verificar se o ciclo de vida das empresas contribui para aumentar o poder explicativo do modelo financeiro da estrutura de capital. Além disso, analisa determinantes da estrutura de capital sugeridos pelas várias teorias que emergiram no último quarto do século passado, nomeadamente, a teoria do efeito fiscal, a teoria dos custos de falência, a teoria da agência e a teoria da informação assimétrica. O estudo incidiu sobre empresas de tecnologias de informação e baseou-se em dados recolhidos através de questionário. Utilizando a análise de clusters, para desenvolver uma taxonomia do ciclo de vida das empresas, e a análise de regressão linear múltipla, para avaliar o poder explicativo de cada determinante proposto para o estudo da estrutura de capital, verificou-se que: (i) as empresas da amostra encontram-se ou na fase de expansão ou na fase de maturidade; (ii) existe uma relação negativa entre o nível de endividamento e os determinantes crescimento e rendibilidade; (iii) as empresas mais jovens recorrem mais ao endividamento; (iv) o nível de endividamento depende directamente do valor colateral dos activos; (v) a dimensão, a poupança fiscal não associada ao endividamento, o risco e o ciclo de vida das empresas parecem não ser determinantes da estrutura de capital das empresas do sector das tecnologias de informação. A evidência reforça o poder explicativo da teoria da pecking order e refuta a possibilidade do ciclo de vida contribuir para as decisões de financiamento.
- Diagnosis and correction of iron chlorosis in fruit trees: a reviewPublication . Correia, Maribela Pestana; de Varennes, A.; Faria, E. A.Several plant species grown in calcareous soils in arid and semiarid regions are iron-deficient, a condition known as lime-induced iron chlorosis, or simply as iron chlorosis. The nutritional status of perennial plants is commonly evaluated by leaf analysis. However, there is often no correlation between iron in leaves and degree of chlorosis, and therefore leaf analysis presents serious limitations as a technique to evaluate lime-induced iron chlorosis. Recently, a technique for the early prognosis of iron chlorosis based on floral analysis was developed for fruit trees to help prevent the development of iron deficiency and avoid losses in yield and quality. Correction of iron chlorosis is commonly carried out by massive applications of synthetic iron chelates to soils. Since iron is rapidly immobilised in the soil, this treatment has to be repeated each year, representing a major part of fertilizer costs. Environmental impacts of chelates in soils have not been properly investigated, but it is known that they also result in enhanced plant uptake of metals such as copper and nickel. Alternative, more environment-friendly treatments are being evaluated. In this article we concentrate on reviewing current methods to detect and correct iron chlorosis in fruit trees.
- Intermolecular alkyl radical addition to methyl 2-(2,6-Dichlorophenyl)-2H-azirine-3-carboxylatePublication . Lemos, A.; Guimaraes, Emanuel; Fortes, Gil; Alves, Maria José ChãoThe 2H-azirine 1 acts as an effective radical acceptor for secondary and tertiary alkyl iodides mediated by triethylborane. The addition proceeds with high regio- and diastereo-selectivity.