903 resultados para September 11


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Sustainable aquaculture Contrasting community management and revenue sharing practices of culture-based fisheries in Lao PDR Saphakdy, B., Phomsouvanh, A., Davy, B., Nguyen, T.T.T. and De Silva, S.S.; Floodplain aquaculture in Begumgonj: New horizon for rural livelihoods in Bangladesh Hossain, M. S.; Promoting small-scale inland aquaculture in Papua New Guinea Edwards, P.; Group approach to shrimp farming: The key to sustainability Kumaran, M.; Research and farming techniques Native catfish culture - a technology package for fish farmers Haniffa, M. A.; An assessment on the influence of salinity in the growth of black clam (Villorita cyprinoides) in cages in Cochin estuary with a special emphasis on the impact of Thennermukkom Salinity Barrier Arun, A. U.; Aquatic animal health EUS in Asia and Africa: Stimulus for regional initiatives!!! Mohan, C.V. Marine Finfish Aquaculture Network Offshore opportunities for artisanal aquaculture Stock, C.; Grouper aquaculture in Brazil Sanches, E.G. and Von Seckendorff, R.W. NACA Newsletter

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Estimates of dolphin school sizes made by observers and crew members aboard tuna seiners or by observers on ship or aerial surveys are important components of population estimates of dolphins which are involved in the yellowfin tuna fishery in the eastern Pacific. Differences in past estimates made from tuna seiners and research ships and aircraft have been noted by Brazier (1978). To compare various methods of estimating dolphin school sizes a research cruise was undertaken with the following major objectives: 1) compare estimates made by observers aboard a tuna seiner and in the ship's helicopter, from aerial photographs, and from counts made at the backdown channel, 2) compare estimates of observers who are told the count of the school size after making their estimate to the observer who is not aware of the count to determine if observers can learn to estimate more accurately, and 3) obtain movie and still photographs of dolphin schools of known size at various stages of chase, capture and release to be used for observer training. The secondary objectives of the cruise were to: 1) obtain life history specimens and data from any dolphins that were killed incidental to purse seining. These specimens and data were to be analyzed by the U.S. National Marine Fisheries Service ( NMFS ) , 2) record evasion tactics of dolphin schools by observing them from the helicopter while the seiner approached the school, 3) examine alternative methods for estimating the distance and bearing of schools where they were first sighted, 4) collect the Commission's standard cetacean sighting, set log and daily activity data and expendable bathythermograph data. (PDF contains 31 pages.)

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The paper reports on a survey on gear assessment for the three intensive fishing seasons in Lake Chad (Nigeria). These seasons coincide with the flood period (Nov-Feb), the receding (March-June)and the recession period (July-September 2001). During this year the questionnaires were requested to ten fishers in each of the selected fishing islands. In the flood season, identified fishing gears on the lake included baited and un-baited Malian traps which constituted about 35% of the total gears recorded. While Ndurutu and Heri (Kung)traps represented, each, 3.2% of the total. About 15.9% of fishers employed hook lines of various length and sizes: Another 15.9% of fishers mounted fish fences (Dumba) during the season. Those that employ seine net accounted for about 11.1% while 9.5% use gill nets.The species belonging to the Cichilidae, Claridae and Osteoglossidae families dominated fish catches. During the receding period, hook lines and fences (Dumba) (6.20%) were found to be predominantly used on the lake due to reducing water level, followed by gill net and draw net which accounted for 17.9% and 16.1 % respectively. During the lake recession only two groups of active gears were recorded. Sixty percent of fishers use combined seine net with cutlass and scoop net, while 40% use to combine only cutlass with kabara net. Fish fences (Dumma)during the flood season were mounted with giant Malian traps of abut 1.5m by 0.5m diameter, covered with net of mesh size (6.3mm-25mm).Each Dumba contained between 150 and 2000 of such traps. Larger number of species was recorded from seine net followed by gill nets and the l kilometre multi mesh fleet drift net. The use of seine net and cutlass known as Genima was predominant during the lake recession

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In this thesis, a method to retrieve the source finiteness, depth of faulting, and the mechanisms of large earthquakes from long-period surface waves is developed and applied to several recent large events.

In Chapter 1, source finiteness parameters of eleven large earthquakes were determined from long-period Rayleigh waves recorded at IDA and GDSN stations. The basic data set is the seismic spectra of periods from 150 to 300 sec. Two simple models of source finiteness are studied. The first model is a point source with finite duration. In the determination of the duration or source-process times, we used Furumoto's phase method and a linear inversion method, in which we simultaneously inverted the spectra and determined the source-process time that minimizes the error in the inversion. These two methods yielded consistent results. The second model is the finite fault model. Source finiteness of large shallow earthquakes with rupture on a fault plane with a large aspect ratio was modeled with the source-finiteness function introduced by Ben-Menahem. The spectra were inverted to find the extent and direction of the rupture of the earthquake that minimize the error in the inversion. This method is applied to the 1977 Sumbawa, Indonesia, 1979 Colombia-Ecuador, 1983 Akita-Oki, Japan, 1985 Valparaiso, Chile, and 1985 Michoacan, Mexico earthquakes. The method yielded results consistent with the rupture extent inferred from the aftershock area of these earthquakes.

In Chapter 2, the depths and source mechanisms of nine large shallow earthquakes were determined. We inverted the data set of complex source spectra for a moment tensor (linear) or a double couple (nonlinear). By solving a least-squares problem, we obtained the centroid depth or the extent of the distributed source for each earthquake. The depths and source mechanisms of large shallow earthquakes determined from long-period Rayleigh waves depend on the models of source finiteness, wave propagation, and the excitation. We tested various models of the source finiteness, Q, the group velocity, and the excitation in the determination of earthquake depths.

The depth estimates obtained using the Q model of Dziewonski and Steim (1982) and the excitation functions computed for the average ocean model of Regan and Anderson (1984) are considered most reasonable. Dziewonski and Steim's Q model represents a good global average of Q determined over a period range of the Rayleigh waves used in this study. Since most of the earthquakes studied here occurred in subduction zones Regan and Anderson's average ocean model is considered most appropriate.

Our depth estimates are in general consistent with the Harvard CMT solutions. The centroid depths and their 90 % confidence intervals (numbers in the parentheses) determined by the Student's t test are: Colombia-Ecuador earthquake (12 December 1979), d = 11 km, (9, 24) km; Santa Cruz Is. earthquake (17 July 1980), d = 36 km, (18, 46) km; Samoa earthquake (1 September 1981), d = 15 km, (9, 26) km; Playa Azul, Mexico earthquake (25 October 1981), d = 41 km, (28, 49) km; El Salvador earthquake (19 June 1982), d = 49 km, (41, 55) km; New Ireland earthquake (18 March 1983), d = 75 km, (72, 79) km; Chagos Bank earthquake (30 November 1983), d = 31 km, (16, 41) km; Valparaiso, Chile earthquake (3 March 1985), d = 44 km, (15, 54) km; Michoacan, Mexico earthquake (19 September 1985), d = 24 km, (12, 34) km.

In Chapter 3, the vertical extent of faulting of the 1983 Akita-Oki, and 1977 Sumbawa, Indonesia earthquakes are determined from fundamental and overtone Rayleigh waves. Using fundamental Rayleigh waves, the depths are determined from the moment tensor inversion and fault inversion. The observed overtone Rayleigh waves are compared to the synthetic overtone seismograms to estimate the depth of faulting of these earthquakes. The depths obtained from overtone Rayleigh waves are consistent with the depths determined from fundamental Rayleigh waves for the two earthquakes. Appendix B gives the observed seismograms of fundamental and overtone Rayleigh waves for eleven large earthquakes.

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The purpose of this thesis is to present new observations of thermal-infrared radiation from asteroids. Stellar photometry was performed to provide standards for comparison with the asteroid data. The details of the photometry and the data reduction are discussed in Part 1. A system of standard stars is derived for wavelengths of 8.5, 10.5 and 11.6 µm and a new calibration is adopted. Sources of error are evaluated and comparisons are made with the data of other observers.

The observations and analysis of the thermal-emission observations of asteroids are presented in Part 2. Thermal-emission lightcurve and phase effect data are considered. Special color diagrams are introduced to display the observational data. These diagrams are free of any model-dependent assumptions and show that asteroids differ in their surface properties.

On the basis of photometric models, (4) Vesta is thought to have a bolometric Bond albedo of about 0.1, an emissivity greater than 0.7 and a true radius that is close to the model value of 300^(+50)_(-30)km. Model albedos and model radii are given for asteroids 1, 2, 4, 5, 6, 7, 15, 19, 20, 27, 39, 44, 68, 80, 324 and 674. The asteroid (324) Bamberga is extremely dark with a model (~bolometric Bond) albedo in the 0.01 - 0.02 range, which is thought to be the lowest albedo yet measured for any solar-system body. The crucial question about such low-albedo asteroids is their number and the distribution of their orbits.

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O combate efetivo ao flagelo secular do terrorismo, ainda que possa se revestir de muitas formas, não prescinde da repressão penal de seus autores. Em vista da maciça internacionalização do terrorismo, a partir do Século XX, a cooperação jurídica internacional em matéria penal (aí incluída a extradição) consolida-se como instrumento de essencial importância para a repressão do terrorismo pela comunidade internacional, com a vantagem de resguardar o domínio do direito e, por conseguinte, de assegurar a paz e a segurança internacionais. A evolução do tratamento do crime de terrorismo pelo direito penal transnacional influenciada pelo direito da segurança coletiva, especialmente a partir dos atentados de 11 de setembro de 2001 exerceu expressivo impacto no direito extradicional. O entendimento desse efeito é fundamental para extrair-se do instituto da extradição todo o seu potencial para a repressão penal do terrorismo. Desde que presentes determinados requisitos, uma conduta de caráter terrorista à luz de parâmetros internacionais gera a obrigação estatal de extraditar ou processar seu autor, mesmo na ausência de tratado. Além disso, a extradição exercida ou não em decorrência de obrigação convencional tem seus princípios afetados pela obrigação internacional de repressão do terrorismo, particularmente no que se refere a questões como extraditabilidade, extradição por crimes políticos e extradição de refugiados. O direito brasileiro apresenta algumas vulnerabilidades para o cumprimento da obrigação aut dedere aut iudicare e a prática judicial brasileira relativa à extradição de acusados de atos de terrorismo poderia reportar-se mais ao direito internacional, com vistas a evitar o risco de violação de obrigações internacionais pelo Brasil.

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The intensities and relative abundances of galactic cosmic ray protons and antiprotons have been measured with the Isotope Matter Antimatter Experiment (IMAX), a balloon-borne magnet spectrometer. The IMAX payload had a successful flight from Lynn Lake, Manitoba, Canada on July 16, 1992. Particles detected by IMAX were identified by mass and charge via the Cherenkov-Rigidity and TOP-Rigidity techniques, with measured rms mass resolution ≤0.2 amu for Z=1 particles.

Cosmic ray antiprotons are of interest because they can be produced by the interactions of high energy protons and heavier nuclei with the interstellar medium as well as by more exotic sources. Previous cosmic ray antiproton experiments have reported an excess of antiprotons over that expected solely from cosmic ray interactions.

Analysis of the flight data has yielded 124405 protons and 3 antiprotons in the energy range 0.19-0.97 GeV at the instrument, 140617 protons and 8 antiprotons in the energy range 0.97-2.58 GeV, and 22524 protons and 5 antiprotons in the energy range 2.58-3.08 GeV. These measurements are a statistical improvement over previous antiproton measurements, and they demonstrate improved separation of antiprotons from the more abundant fluxes of protons, electrons, and other cosmic ray species.

When these results are corrected for instrumental and atmospheric background and losses, the ratios at the top of the atmosphere are p/p=3.21(+3.49, -1.97)x10^(-5) in the energy range 0.25-1.00 GeV, p/p=5.38(+3.48, -2.45) x10^(-5) in the energy range 1.00-2.61 GeV, and p/p=2.05(+1.79, -1.15) x10^(-4) in the energy range 2.61-3.11 GeV. The corresponding antiproton intensities, also corrected to the top of the atmosphere, are 2.3(+2.5, -1.4) x10^(-2) (m^2 s sr GeV)^(-1), 2.1(+1.4, -1.0) x10^(-2) (m^2 s sr GeV)^(-1), and 4.3(+3.7, -2.4) x10^(-2) (m^2 s sr GeV)^(-1) for the same energy ranges.

The IMAX antiproton fluxes and antiproton/proton ratios are compared with recent Standard Leaky Box Model (SLBM) calculations of the cosmic ray antiproton abundance. According to this model, cosmic ray antiprotons are secondary cosmic rays arising solely from the interaction of high energy cosmic rays with the interstellar medium. The effects of solar modulation of protons and antiprotons are also calculated, showing that the antiproton/proton ratio can vary by as much as an order of magnitude over the solar cycle. When solar modulation is taken into account, the IMAX antiproton measurements are found to be consistent with the most recent calculations of the SLBM. No evidence is found in the IMAX data for excess antiprotons arising from the decay of galactic dark matter, which had been suggested as an interpretation of earlier measurements. Furthermore, the consistency of the current results with the SLBM calculations suggests that the mean antiproton lifetime is at least as large as the cosmic ray storage time in the galaxy (~10^7 yr, based on measurements of cosmic ray ^(10)Be). Recent measurements by two other experiments are consistent with this interpretation of the IMAX antiproton results.

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Recent research has shown that the biomass of bacteria in lakes and other water-bodies can attain significant values. The huge production of bacteria is brought about by their great rate of reproduction. In a series of cases their biomass exceeds the biomass of phytoplankton. Therefore in a study of the biological productivity of water bodies it is necessary to calculate the biomass and production not only of the phyto- and zooplankton, but also of bacteria.The authors uses different methods and formulae to to compare the time of one generation of the bacteria.

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The original method, proposed by Yentsch (1957), of determination of chlorophyll directly in the cells, attracts attention by its simplicity. In order to measure the content of chlorophyll by this method, a determined volume of suspension of algae is filtered through a membrane filter. The latter is dried a little, clarified by immersion oil, clamped between two glasses, and spectrophotometrized. Extinction is read off at , wavelengths equal to 670 millimicrons (around the maximum absorption of chlorophyll a in the cell) and 750 millimicrons (correction for non- specific absorption and dispersion of light by particles of the preparation). The method of Yentsch was employed by the authors for determination of chlorophyll-a in samples of phytoplankton. They conclude that in spite of the simplicity and convenience of determination the method must be applied sufficiently carefully. It is more suitable for analysis of cultures of algae, where, non-specific absorption of light is insignificant.

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The study of enzymatic activity is of great importance in the immunology of fungi. Indeed, knowledge of biological activity of antigenic structures is important for the elucidation of host-parasite relations as well as in the search for a taxonomic factor permitting differential diagnoses. The authors used Saprolegnia cultures to analyse soluble antigenic fractions arising from the mycelium of cultures of 4 species of Saprolegnia, which are found most frequently in the parasitic state on fish: S. parasitica, S. ferax, S. delica, S. diclina. The authors conclude that in the study of saprolegniasis, the enzymatic approach affords new elements for the examination of the etiology of fungi as well as an element of gravity concerning the biochemical modifications necessary to the change of saprophytism to parasitism.

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This partial translation of a longer article describes the phenomenon of ”Blasensand”. Blasensand is formed when sedimentation of dried out sand is suddenly flooded from above. A more detailed explanation of Blasensand is given in this translated part of the paper.