Investigación pesquera: perspectiva actual, tensiones y aspectos emergentes. El futuro y su aproximación

[EN] The current development of fishery research can be considered as much a technical development as a scientific-conceptual one. In relation to the technical development we analyse the evolution of the concepts fishing effort and fishing power, as well as vulnerability, availability and accessibility. In the conceptual analysis of the basic parameters we consider new contributions with regards to recruitment and evolution of populations based on concepts such as the system’s carrying capacity and the effect of inverse density dependence. The impact of the available space is analysed as well as the effect of the prey-predator relationship in the context of the flows between the different levels in the trophic web. We point out that fishery analysis strategies need to consider that, from both the biological and socio-economic points of view, the system is never balanced but rather is at the very limit or even over the limit. On the whole, fishing (human action on the resource) can be understood within the context of the ecosystem. This situation implies introducing the concept of uncertainty. Aspects such as ecosystem elasticity are analysed in their broadest sense. In these terms, recovery of an ecosystem and of Large Marine Ecosystems (LME) is still possible, but the result can be different due to the appearance of opportunistic species. Some concepts such as fuzzy sets, and chaos and fractal analysis are important tools for analysing the evolution and management of ecosystems exploited by fisheries[ES] El desarrollo actual de la ciencia de las pesquerías es considerado tanto como desarrollo técnico como desarrollo científico-conceptual. En el primer aspecto se analiza la evolución de los conceptos: esfuerzo de pesca y poder de pesca. Así como la vulnerabilidad disponibilidad y accesibilidad. Se considera el análisis conceptual de los parámetros básicos con nuevas aportaciones sobre el reclutamiento y la evolución de las poblaciones a partir de conceptos como la capacidad de carga del sistema y el efecto de la densodependencia inversa. Se analiza el impacto del espacio disponible así como el efecto de la relación presa-depredador en el contexto de los flujos entre los diversos niveles de la relación trófica. La estrategia se sitúa considerando que tanto desde el punto de vista biológico como socieconómico el sistema no está nunca en equilibrio sino en el límite o fuera del mismo. En conjunto la pesca –acción del hombre sobre el recurso– se sitúa en el contexto del ecosistema. Esta situación implica introducir situaciones de incertidumbre. Se analizan aspectos como la elasticidad de los ecosistemas en su aspecto amplio. En estos términos la recomposición de un ecosistema y también de Large Marine Ecosystems (LME) es posible, pero el resultado puede ser diferente –aparición de especies oportunistas. Algunos conceptos como los conjuntos borrosos, el análisis caótico y la fractalidad son instrumentos importantes en el análisis de la evolución y el control de los ecosistemas depredados por la pescaPeer reviewe

Stochastic analysis of different rough surfaces

This paper shows in detail the application of a new stochastic approach for the characterization of surface height profiles, which is based on the theory of Markov processes. With this analysis we achieve a characterization of the scale dependent complexity of surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities. The method is applied to several surfaces with different properties, for the purpose of showing the utility of this method in more details. In particular we show the evidence of Markov properties, and we estimate the parameters of the Fokker-Planck equation by pure, parameter-free data analysis. The resulting Fokker-Planck equations are verified by numerical reconstruction of conditional probability density functions. The results are compared with those from the analysis of multi-affine and extended multi-affine scaling properties which is often used for surface topographies. The different surface structures analysed here show in details advantages and disadvantages of these methods.Comment: Minor text changes to be identical with the published versio

ANOMALOUS GAUGE BOSON INTERACTIONS

We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge boson self-interactions. If the energy scale of the new physics is $\sim 1$ TeV, these low energy anomalous couplings are expected to be no larger than ${\cal O}(10^{-2})$. Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.Comment: 53 pages with 17 embedded figures, LaTeX, uses axodraw.sty, figures available on request. The complete paper, is available at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z or http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z Summary of the DPF Working Subgroup on Anomalous Gauge Boson Interactions of the DPF Long Range Planning Stud

Organizing Equity Exchanges

In the last years equity exchanges have diversified their operations into business areas such as derivatives trading, posttrading services, and software sales. Securities trading and post-trading are subject to economies of scale and scope. The integration of these functions into one institution ensures efficiency by economizing on transactions costs. Using balanced panel data from major equity exchanges over the period 2005-2007, we examine empirically the presence of economies of scale in securities trading. Moreover, we analyze the impact of vertical integration of trading, clearing, and settlement, the impact of the size of an exchange, and the impact of diversification on the profitability of exchanges. The evidence confirms that a large number of transactions leads to low costs per trade. The evidence shows that the profitability of equity exchanges is highest for vertically integrated exchanges and that diversification and size have a negative impact on their profitability

B-mode and colour Doppler sonographic examination of the milk vein and musculophrenic vein in dry cows and cows with a milk yield of 10 and 20 kg

BACKGROUND: This study investigated the effect of milk yield on blood flow variables in the milk vein and musculophrenic vein in dairy cows. METHODS: Five healthy dry cows, five cows with a daily milk yield of 10 kg and five others with a daily milk yield of 20 kg underwent B-mode and colour Doppler sonographic examination. The diameter of the veins, blood flow velocities and blood flow volumes were measured on both sides in standing, non-sedated cows using a 7.5 MHz linear transducer. RESULTS: Lactating cows had significantly higher blood flow velocities in the milk vein than dry cows; the maximum blood flow velocity of dry cows and those with a daily milk yield of 10 and 20 kg were 14.04, 38.77 and 39.49 cm/s, respectively, the minimum velocities were 0.63, 3.02 and 2.64 cm/s, respectively, and the mean maximum velocities were 8.21, 26.67 und 28.22 cm/s, respectively. Cows producing 20 kg of milk a day had a blood flow volume of 3.09 l/min, which was significantly higher than 0.79 l/min recorded in dry cows. Lactating cows had significantly higher mean maximum blood flow velocities in the musculophrenic vein than dry cows. Blood flow variables of both veins did not differ significantly between the left and right side. CONCLUSION: This study showed that milk yield has a profound effect on blood flow variables in the milk vein and to a lesser extent the musculophrenic vein. This must be taken into consideration in future Doppler sonographic studies of these veins and possibly other vessels. Furthermore, measurements on one side are representative of both sides

Atomic spectroscopy studies of short-lived isotopes and nuclear isomer separation with the ISOLDE RILIS

The Resonance Ionization Laser Ion Source (RILIS) at the ISOLDE on-line isotope separator is based on the selective excitation of atomic transitions by tunable laser radiation. Ion beams of isotopes of 20 elements have been produced using the RILIS setup. Together with the mass separator and a particle detection system it represents a tool for high-sensitive laser spectroscopy of short-lived isotopes. By applying narrow-bandwidth lasers for the RILIS one can study isotope shifts (IS) and hyperfine structure (HFS) of atomic optical transitions. Such measurements are capable of providing data on nuclear charge radii, spins and magnetic moments of exotic nuclides far from stability. Although the Doppler broadening of the optical absorption lines limits the resolution of the technique, the accuracy of the HFS measurements examined in experiments with stable Tl isotopes approaches a value of 100 MHz. Due to the hyperfine splitting of atomic lines the RILIS gives an opportunity to separate nuclear isomers. Isomer selectivity of the RILIS has been used in studies of short-lived Ag, Cu and Pb isotopes