Showing papers by "University of Lisbon published in 1982"
TL;DR: Results suggest that the majority of the abnormalities which appear in larval fish are lethal, while those which become apparent only in the post-larval fish (after 40 days) do not interfere with survival.
Abstract: The main types of body deformation found in sea bass, Dicentrarchus labrax (L), reared at the Centre Oceanologique de Bretagne, from hatching to 100 days, are described and classified. Frequency of occurrence of each type of abnormality was followed in different batches of reared fishes. Results suggest that the majority of the abnormalities which appear in larval fish are lethal (from 0 to 40 days), while those which become apparent only in the post-larval fish (after 40 days) do not interfere with survival.
108 citations
TL;DR: Two ferredoxins from Desulfovibrio desulfuricans, Norway Strain, were investigated by EPR spectroscopy and showed a more complex spectrum, indicating an interaction between two [4Fe-4S] clusters, and probably, has two clusters per protein subunit.
27 citations
01 Jan 1982
11 citations
TL;DR: In this paper, Deuteron and proton-induced cross sections and cross section ratios for In, Sb and Ce in the incident energy range 0.3 to 1 MeV/amu obtained from thin target measurements are presented.
10 citations
TL;DR: In this paper, the authors present a dynamic model which explains output, enployment and energy consumption in the French manufacturing sector in terms of the expected and actual path of wage rates and energy prices in units of output.
Abstract: In this paper, we present a dynamic model which explains output, enployment and energy consumption in the French manufacturing sector in terms of the expectedand actual path of wage rates and energy prices in units of output. The modelhas two distinguishing features: First, the rate of capacity utilization isdetermined explicitly from profit-maximizing behavior and it is viewed as the crucial adjusting variable in the short run. Second, we assume complete lack of substitutability between capital, labor and energy inputs ex post.The model is motivated by a brief discussion of French growth, focusing on the decline of profitability and employment in manufacturing, and simulated using annual data from 1950 to 1979. The wage explosion and the energy shock of the early seventies are interpreted (in a model allowing for overhead labor) in terms of changes in expected real factor prices,and their effects on the utilizationand the profitability of each vintage are quantified. Aggregating over vintages,the model generates the observed decline in profitability and utilization of existing capacity. The results of the simulation are very encouraging, and a simultaneous estimation of the model under static expectations is rejected by the data. There are two limitations of the analysis which will be relaxed in further work. Investment is exogenous and open-economy aspects only appear indirectly, say via constraints on the energy price and the price of output.
10 citations
TL;DR: Although this method tended to attenuate major spectral peaks drastically few classification errors occured, the experiment can be taken as a demonstration of an unexpected ability of the perceptual system to compensate for static filtering effects.
9 citations
TL;DR: In this article, the optimal portfolio of an international investor who consumes N national composite goods and who holds N domestic-currency-denominated assets with known nominal interest rates in an environment where prices of goods, assets and exchange rates follow geometric Brownian motion is presented.
Abstract: Using a continuous-time finance-theoretic framework, this paper presents the optimal portfolio rule of an international investor who consumes N national composite goods and who holds N domestic-currency-denominated assets with known nominal interest rates in an environment where prices of goods, assets and exchange rates follow geometric Brownian motion. It is shown that the currency portfolio rule described in Macedo (1982a) is applicable to the case where there are N assets with a known price and one asset, gold, with a random rice in terms of the numeraire. Under these assumptions, it is found that the optimal portfolio of an investor consuming goods from all major industrialized countries (according to their weight in total trade) would be dominated in March 1981 by long positions in U.S. dollars (25%), yen (17%), D. marks (16%), French francs (15%) and pounds sterling (10%). An investor consuming only U.S. goods, by contrast, would hold 96% of his optimal portfolio in U.S. dollars. Because of the covariance of exchange rates and gold, the exclusion of the latter generates substantial reshuffling. The analysis of the evolution of portfolios over time shows that shares changed dramatically at the beginning of the period and did not begin to approach their March 1981 values until the end of 1975. In the case of the yen and the pound there were oscillations throughout the period. With respect to the dollar share in the optimal portfolio of the U.S. and international investor, it is found that, in the period between late 1974 and mid-1976, a period in which the dollar is considered to have been "strong", a large decline in its optimal share took place.
8 citations
4 citations
Posted Content•
TL;DR: In this paper, the optimal consumption and portfolio rules for an international investor with constant expenditure shares [alpha, sub j] and constant relative risk aversion [1-gamma] in a dynamic context were derived.
Abstract: In the framework of continuous-time finance theory, this paper derives the optimal consumption and portfolio rules for an international investor with constant expenditure shares [alpha, sub j] and constant relative risk aversion [1-gamma] in a dynamic context. The index of value obtained from the consumption rule is used to obtain real returns on N different currencies in terms of their purchasing power over N goods. The portfolio rule is expressed in terms of the determinants of the purchasing powers, namely exchange rates and prices expressed in the numeraire currency. The optimal portfolio is interpreted as a capital position given by the expenditure shares and hedging zero net-worth portfolios depending on unanticipated inflation and risk aversion. It is shown that the minimum variance portfolio is independent of returns, but depends on expenditure patterns. While the speculative portfolio depends on risk aversion and real return differentials. When the effect of references on real return differentials is made explicit, it is shown that the minimum variance portfolio is affected by risk aversion. In that case, the effect of an increase in [alpha, sub i] on the portfolio proportions [x, sub i] will be positive when relative risk aversion is greater than one, as generally presumed. Actual data from eight major countries is used to compute optimal portfolios based on real return differentials for different weighting schemes, degrees of risk aversion and sample periods when exchange rates and prices are assumed to be Brownian.
4 citations
TL;DR: In this article, the gamma-gamma time differential perturbed angular correlation method was used to measure the half-life of the 53-kV state in an external magnetic field of 25.1 kG using the 346-53 keV gamma cascade.
Abstract: The nuclear levels in $^{197}\mathrm{Pt}$ have been studied from the decay of 95.4 min $^{197}\mathrm{Pt}^{m}$. The isomeric state was produced by ($n$,$\ensuremath{\gamma}$) reaction on the enriched $^{196}\mathrm{Pt}$. The $\ensuremath{\gamma}$-ray spectra have been observed with a hyperpure Ge detector and a large volume Ge(Li) detector. The half-lives of the 399 keV and the 53 keV states were determined with improved precision. The results are ${T}_{\frac{1}{2}}$ (399 keV) =95.41\ifmmode\pm\else\textpm\fi{}0.18 min and ${T}_{\frac{1}{2}}$ (53 keV)=16.58\ifmmode\pm\else\textpm\fi{}0.17 ns. The $g$ factor of the 53 keV ${\frac{5}{2}}^{\ensuremath{-}}$ state has been measured by the gamma-gamma time differential perturbed angular correlation method in an external magnetic field of 25.1 kG using the 346-53 keV gamma cascade. The value of the $g$ factor was obtained to be +0.335\ifmmode\pm\else\textpm\fi{}0.010. This result is compared with the known $g$ factors of the similar states in $^{195}\mathrm{Pt}$, and in $^{197}\mathrm{Hg}$ and $^{199}\mathrm{Hg}$, and also with theoretical calculations based on the quasiparticle-phonon coupling scheme. The possibility of using the 346-53 keV gamma cascade in $^{197}\mathrm{Pt}$ in the future time differential perturbed angular correlation studies is discussed.RADIOACTIVITY $^{197}\mathrm{Pt}^{m}$ [from $^{196}\mathrm{Pt}$$(n,\ensuremath{\gamma})^{197}\mathrm{Pt}^{m}$]; measured ${E}_{\ensuremath{\gamma}}$, ${I}_{\ensuremath{\gamma}}(t)$, $\ensuremath{\gamma}\ensuremath{\gamma}(t)$, $\ensuremath{\gamma}\ensuremath{\gamma}(\ensuremath{\theta},T,H)$, ${T}_{\frac{1}{2}}$; deduced $B(E2)$, $\ensuremath{\mu}$; calculated $B(E2)$, $\ensuremath{\mu}$; Ge(Li), Ge hyperpure, NaI(T1) detectors. Enriched target.
4 citations
TL;DR: A microprocessor controlled MCA, in which direct memory access techniques are used to allow fast acquisition rates, is presented and the corresponding programs and subroutines are described and their source and object codes are made available.
01 Dec 1982
TL;DR: In this article, the spatial distribution of various energy forms, for each of the three periods October-March (summer semester), April-September (winter semester) and the year is shown in tabular and graphical forms, including latitudinal and vertical cross sections.
Abstract: Results of evaluation of different forms of available potential energy and kinetic energy based on direct observations of temperature, wind and geopotential carried out in southern hemisphere during the IGY, are presented. The spatial distribution of various energy forms, for each of the three periods October–March (summer semester), April–September (winter semester) and the year is shown in tabular and graphical forms, including latitudinal and vertical cross sections. The theoretical framework this investigation is based on, consists of the general equations of atmospheric energetics in the space-time domain. It is found that the highest seasonal values occur generally in winter, the most important contributions to eddy energy forms being due to transient eddies.
01 Jan 1982
01 Jan 1982
TL;DR: In this article, a comparison of reference systems employed by classical and modern techniques of observing the Earth's rotation is presented, and advantages and disadvantages of the systems so far employed are discussed.
Abstract: A comparison is presented of reference systems employed by classical and modern techniques of observing the Earth’s rotation. Advantages and disadvantages of the systems so far employed are discussed. The observing campaign of project “MERIT” emphasizes the need for consistent systems of reference. Any future system of reference for the Earth’s dynamics should be well defined in order to avoid past ambiguities. The future of the Conventional International Origin and proposals about the Conventional Terrestrial System to be adopted by international agreement are presented.