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.
- Ultra light vertical array remote data acquisition system (ULVA RDAS)Publication . Felisberto, P.; Lopes, C.; Carmo, A.In 1997, CINTAL has requested Co.L.Mar Srl. (Italy) to provide the plans and the execution for a multichannel Ultra Light Vertical Array (ULVA) underwater acoustic passive system to support its research plans under project INTIMATE (FCT contract 2/2.1/MAR/1698/95). The solution proposed by Co.L.Mar was composed of a vertical line array (VLA) with 16 hydrophones, a radio buoy with an RF data link to a base station, interfaced to a DAT recorder. Under the same project, CINTAL has developed a PC based system that interfaced to the RF receiver on the base station would allow to acquire on computer disk and monitor the signals being received on line - this is the Data Acquisition and Monitoring System (DAMS). The ensemble composed of the receiving array, the RF link and the PC monitoring system will referred to in this report as the ULVA/DAMS system. The ULVA/DAMS system was first tested at sea in July 1999 and then sucessfully operated during the INTIFANTE 00 sea trial in October 2000.
- A construção da autonomia nas crianças em contexto de jardim de infânciaPublication . Afonso, Ana Margarida Bandarra Faustino; Gonçalves, José Alberto Mendonça; Sousa, Carolina Moreira deO presente estudo, de carácter exploratório, baseia-se no pressuposto de que a autonomia assume particular importância no desenvolvimento da pessoalidade. E portanto, uma dimensão integrante na estruturação da identidade pessoal, cujo desenvolvimento é influenciado pela qualidade das interacções que a criança estabelece nos diferentes contextos de vida em que se insere, do qual se destaca o contexto educativo.
- Shallow water tomography with a sparse array during the INTIMATE'98 sea trialPublication . Felisberto, P.; Jesus, S. M.; Stephan, Y.; Demoulin, X.Invert acoustic data using sparse arrays - at the limit with a single hydrophone - is a challenging task. The final goal is to obtain a rapid environmental assessment with systems both easier to deploy and less expensive than full vertical arrays. In this paper, it is shown that using a known broadband source signal and an array with few hydrophones, ocean acoustic tomography can be performed, even in a complex internal waves induced highly variable ocean. The inversion approach presented herein is based on an arrival matching processor and a genetic algorithm search procedure. Due to the poor accuracy on the a priori knowledge of the source range, source depth and water depth, the inversion procedure was split in two stages: in the first stage the geometric parameters where estimated and in the second stage sound speed estimates where obtained. This procedure was applied to field data, acquired during the INTIMATE'98 sea trial, in a shallow water area off the coast of France in the Gulf of Biscay. That area is expected to have a relatively high internal wave activity, specially during the summer. A 4 sec long - 700 Hz bandwidth linear frequency modulated signal was transmitted from a ship suspended sound source and received on a 4 element vertical array at a range of approximately 10.5 km, over a relatively range-independent area. The results from the inversion of the acoustic data are in line with those obtained by concurrent non acoustic data like GPS source range, measured source depth, XBT casts and temperature sensors.
- Parameters determination for the coupled electromagnetic transformer model, with particular reference to winding faults studiesPublication . Oliveira, L. M. R.; Cardoso, A. J. MarquesIn the past few years, a considerable research effort has been devoted to the development of transformer digital models in order to simulate its behaviour under transient and abnormal operating conditions. Although many three-phase transformer models have been presented in the literature, there is a surprisingly lack of studies regarding the incorporation of winding faults. This paper presents a coupled electromagnetic transformer model for the study of winding inter-turn short-circuits. Particular attention will be given to the model parameters determination, for both healthy and faulty operating conditions. Experimental and simulation test results are presented in the paper, demonstrating the adequacy of the model as well as the methodologies for the parameters determination.
- Nutrient deficiencies in carob (Ceratonia siliqua L.) grown in solution culturePublication . Correia, P. J.; Pestana, M.; Martins-Loução, M. A.The hypothesis was tested that carob (Ceratonia siliqua L.) is able to develop morphological and physiological adaptations to tolerate or at least mitigate soil nutrient deficiencies. In this work we studied the effects of N, P, Mg, Ca and Fe deficiencies on plant morphology, biomass partitioning, concentrations of chlorophyll, fluorescence and root tip ferric chelate-reductase in carob rootstocks grown in hydroponics. Young rootstock trees were grown in hydroponics with half-strength Hoagland's solution (control) or without N, P, Mg, Ca and Fe (treatments N0, P0, Mg0, Ca0 and Fe0). Nitrogen, and P deficiency affected shoot and root growth but not biomass partitioning or photosynthetic efficiency. Plants without Mg had a few large non-ramificated roots and low photosynthetic efficiency, similar to the Fe-starved plants. Root ferric chelate-reductase activity (FC-R) expressed on a fresh weight basis was higher under P and Mg deficiencies compared with control plants, but Fe0 plants had lower FC-R activity if dry weights are used. The response of carob-tree to these particular nutrients depletion may support the ecological plasticity of this species. Under natural conditions, lack of Fe and Mg in the soil is not likely to occur, but if N and P are limiting, carob growth (shoot and root dry weights) may be negatively affected. Even so, photosynthetic efficiency is maintained, and under P stress FC-R activity may increase.
- José Manuel Fraile Gil, Romances de Salio (Riaño - León). Una tradición ahogada, [Torrelavea], Cantabria Tradicional, 2001, 118 pp. + 1 CDPublication . Galhoz, Maria AlieteNão é uma obra documentando só o subgénero do romance, como o título levaria a supor. O autor levanta a memória, vivencial e cultural, de uma pequena povoação leonesa, Salio, desaparecida, com outras, na execução de um planeamento de retenção de recursos hídricos, para efeitos de irrigação mais vasta — com a consequência de dispersão e realojamento, em outros lugares, dos habitantes dali retirados.
- Endocrine correlates of intra-specific variation in the mating system of the St. Peter's fish (Sarotherodon galilaeus)Publication . Ros, A. F. H.; Canario, Adelino V. M.; Couto, Elsa; Zeilstra, IIja; Oliveira, R. F.The Challenge Hypothesis postulates that androgen levels are a function of the social environment in which the individual is living. Thus, it is predicted that in polygynous males that engage in social interactions, androgen levels should be higher than in monogamous animals that engage in parental care. In this study, we tested this hypothesis at the intra-specific level using a teleost species, Sarotherodon galilaeus, which exhibits a wide variation in its mating system. Experimental groups of individually marked fish were formed in large ponds with different operational sex-ratios (OSR) to study the effects of partner availability on blood plasma levels of sex steroids [11-ketotestosterone (11-KT), testosterone (T), and 17,20B-dihydroxy-4-pregnen-3-one (17,20B-P)] and gonadosomatic index (GSI). Polygyny mostly occurred in the female biased OSR groups. 17,20B-P and gonadosomatic index did not differ among OSR groups. However, 11-KT was high in male biased OSR and positively correlated with aggressive challenges, thereby supporting the central postulate of the Challenge Hypothesis. The results of T were the inverse of those of 11-KT, probably because 11-KT is metabolized from T. 11-KT levels of polygynous males did not differ neither from those of monogamous males, nor from those of males that participated in parental care. These results do not support the expected relationships between polygyny, parental care, and androgen levels. The differences from expectations for 11-KT may be related to the fact that in S. galilaeus, the mating and the parenting phase are not clearly separated and thus, males may still fight and court while they are brooding.
- Aqueous photochemistry of pesticides triadimefon and triadimenolPublication . Silva, José P. da; Ferreira, Luís F. Vieira; Silva, Abílio M. daThe photochemistry of pesticides triadimefon and triadimenol was studied in aqueous solution and in methanol/water mixtures, in controlled and natural conditions. The photodegradation kinetics and product distribution are strongly dependent on the solvent and on the irradiation wavelength. The degradation rates are faster at 254 nm than at 313 nm. The kinetics is faster in water than methanol. Direct photoreaction is an important dissipation pathway of triadimefon in natural water systems while triadimenol is stable in these conditions. 1,2,4-Triazole and 4-chlorophenol are two of the major photodegradation products. The formation of the 4-chlorophenoxyl radical was detected for both pesticides in methanol and methanol/water mixtures. In methanol/water mixtures the reaction of both pesticides also occurs with 4-chlorophenolate formation, which increases with the water content. The photochemical studies of pesticides and other pollutants should be made in conditions as similar as possible to those observed in environmental systems. (C) 2003 Elsevier Science B.V. All rights reserved.
- Effect of the essential volatile oils isolated from Thymbra capitata (L.) Cav. on olive and sunflower oilsPublication . Miguel, Maria Graça; Figueiredo, A. C.; Costa, M. M.; Martins, D.; Barroso, J. G.; Pedro, L. G.The chemical composition of the volatile constituents of the oils isolated from different parts of Thymbra capitata collected at different developmental stages were analysed by GC and GC/MS. The antioxidant ability of the oils isolated from T capitata was evaluated determining the peroxide values, on olive and sunflower oils, stored at 60 degreesC. These peroxide values were compared with those obtained when BHT, carvacrol and control (without adding antioxidants) were used and subjected to the same conditions. The best yield oil was obtained from the whole aerial part of T capitata collected during the flowering phase. The major component of the oils was carvacrol. Relative high amounts of p-cymene, gamma-terpinene and beta-caryophyllene were also found. BHT revealed to be the best antioxidant when the olive oil was used. On sunflower oil, the antioxidant ability of BHT was not so evident, being the carvacrol-rich essential oils of T capitata or carvacrol more important antioxidants.
- Diets of the sole Solea vulgaris Quensel, 1806 and Solea senegalensis Kaup, 1858 in the lower estuary of the Guadiana River (Algarve, southern Portugal): Preliminary resultsPublication . Sá, R.; Bexiga, C.; Vieira, L.; Veiga, Pedro; Erzini, KarimThe feeding habits of two major species of sole, the common sole Solea vulgaris Quensel, 1806 and the Senegalese sole Solea senegalensis Kaup, 1858 were studied in the lower estuary of the Guadiana River (Algarve, southern Portugal). An evaluation of the number, weight, and feeding coefficient of prey types showed that S. vulgaris feed on a limited variety of prey (only Polychaeta and Tanaidacea) and present low-intensity feeding activity, with small differences in diet between seasons. S. senegalensis also have a low-diversity diet (with only one more taxa, Amphipoda), but exhibit more intense feeding activity which varies seasonally, although with little seasonal variation in the relative importance of the main preys. The diet composition of these two species suggests feeding specialization.