Toward an Ecological Explanation of Agricultural Unemployment in Bangladesh

Cultural ecology theoretical framework was found suitable to explain unemployment in agriculture in three villages in Bangladesh. Path analysis and multiple regression statistics were used to examine the direct, indirect, and total effects of eight independent human, social, environmental, and technology variables as well as their aggregate contribution on agricultural unemployment. The multiple regression model explains 86.2% of the total variation in unemployment in agriculture; they were followed by environmental constraints and labor saving technology variables.     

Longitudinal vibration of non-homogeneous earth dams

Two-dimensional analytical elastic models are developed for evaluating dynamic characteristics, namely natural frequencies and modes of vibration of a wide class of earth dams in a direction parallel to the dam axis. In these models the non-homogeneity of the dam materials is taken into account by assuming a specific variation of the stiffness properties along the depth (due to the continuous increase in confining pressure). In addition, both shear and normal (axial) deformations are considered. Cases having constant elastic moduli, linear and trapezoidal variations of elastic moduli, and elastic moduli increasing as the one-half, one-third, two fifths, and a general (l/m)th powers of the depth are studied. Dynamic properties of three real earth dams in a seismically active area (Southern California) estimated from their earthquake records (input ground motion and crest response in the longitudinal direction) as well as results from full-scale dynamic tests on one of these dams (including ambient and forced vibration tests) are compared with those from the suggested models. It was found that the models in which the shear modulus and the modulus of elasticity of the dam material vary along the depth are the most appropriate representations for predicting the dynamic characteristics. The agreement between the experimental and earthquake data and the theoretical results from some of the models is reasonably good.     

Electrochemical studies of sulphides,I. The electrocatalytic activity of galena,pyrite and cobalt sulphide for oxygen reduction in relation to xanthate adsorption and flotation

The electrocatalytic activity of galena, pyrite and Co₃S₄ for oxygen reduction has been studied by potentiostatic methods. Open circuit potentials of the sulphide electrodes have also been measured as a function of pH in nitrogen, air and oxygen atmospheres and also in the presence of H₂O₂ and ethyl xanthate. The adsorption of xanthate on sulphides was followed by observing bubble attachment to the electrodes.The catalytic activity for oxygen (or H₂O₂) reduction (the cathodic currents), the electrode potentials and the xanthate adsorption as shown by bubble attachment within certain pH limits, all varied as $\text{Co}{}_3\text{S}{}_4\text{> pyrite (≈ PbS in H}{}_2\text{O}{}_2\text{) ? PbS}$ indicating considerable dependence of the redox processes in flotation on the d - electron character of the sulphides.In the absence of oxygen, xanthate is probably bonded to the water structure of the surface through hydrogen-bonding, thus keeping the surface hydrophilic. Such adsorption reduces the electrode potential and inhibits oxygen reduction.     

Evidence of the impacting body of the Ries crater — the discovery of Fe-Cr-Ni veinlets below the crater bottom

Fe-Cr-Ni particles and veinlets have been discovered in the top 15 m of the compressed zone with abundant shatter cones below the bottom of the Ries crater. The metallic particles are less than a few microns across. They occur in various minerals along healed intergranular and locally in intragranular microfractures in quartz diorite, amphibolite and chloritized granite of the basement crystalline rocks.The particles consist of major Fe, Cr, and Ni with minor Si and Ca. Origin due to contamination is absolutely ruled out. We believe that these Fe-Cr-Ni particles are probably condensed from the vaporized impacting body which produced the Ries crater. These particles were injected with high velocity into microfractures near the top of the compressed zone, implanted in and across various minerals before these microfractures were resealed. The presence of Si and Ca as well as the fact that the Cr content is nearly twice that of Ni, led us to conclude that the Ries impacting body is very likely not an iron meteorite but a stony meteorite.     

利用SRTM绘制东Sahara大型古排水盆地及其对南埃及新发展计划的影响(英文)

In the current study, the shuttle radar topography mission (SRTM) data, with～90 m horizontal resolution, were used to delineate the paleodrainage system and their mega basin extent in the East Sahara area. One mega-drainage basin has been detected, covering an area of 256 000 km2. It is classified into two sub mega basins. The Uweinate sub mega basin, which is composed of four main tributaries, collected water from a vast catchment region and drained eastward from the north, west, and southwest, starting at...     

Ecological quality of some Tunisian coast and lagoon locations,by using benthic community parameters and biotic indices

Three Tunisian coastal and lagoon sites, variously affected by human activities, and differing according to their degree of communication with the sea, were studied. The total organic matter content and the granulometry of the sediment were measured and the macro-invertebrates were sampled and identified. Currently due to the lack of an efficient single biotic index for quality assessment, indications from these measurements can contribute to enrich our knowledge of the southern Mediterranean areas. Several biotic indices (AMBI, BENTIX, BOPA, BOPA modified, I2EC, ITI), most of which have been used in the context of the European Water Framework Directive, and some other structural parameters were used. The results show that the Bizerte lagoon, an almost closed area characterized mainly by extreme salinity/temperature and with a strong fluctuation of nutrients, appears biologically more impoverished. The Dkhila coast, which is more open to the sea, however, appears to be less dominated by the principal species. Biotic indices showed that the most polluted areas included the region exposed to urban inputs of Bizerte, the mouth of Hamdoun wadi and the harbour areas. In these locations, benthic macrofauna is dominated by opportunistic species like Capitella capitata, Scolelepis fuliginosa, Prionospio malmgreni, Polydora sp., Cirratulus cirratus and Cirriformia tentaculata. Other stations, which are farther from the sources of disturbance such as the mouths of the principal Wadis, the south of the Bizerte ship canal and the south of the Tunis bay, appear to be in good ecological condition and hosted a variety of sensitive species, Other stations were classified differently by the biotic indices used mainly because of the lack of a real inter-calibration of the various classification methodologies used by these indices.     

Intellectual property rights and the transfer of climate change technologies: issues,challenges, and way forward

The role of intellectual property rights (IPRs) in the development and transfer of climate change technologies has been a contentious issue in negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). Irreconcilable differences seem to oppose those who believe IPRs are an inherent barrier to the transfer of climate change technologies and those who argue they are an essential incentive to innovation. After providing an overview of the polarized debate on this issue, this article reviews the existing literature and empirical evidence and looks into some practical initiatives and recent developments. Finally, it seeks to identify a way forward that could help overcome the current stalemate in international deliberations by suggesting a number of parameters to structure the discussion on this complex issue.     

High oxidation state during formation of Martian nakhlites

Abstract– The oxygen fugacities recorded in the nakhlites Nakhla, Yamato‐000593 (Y‐000593), Lafayette, and NWA998 were studied by applying the Fe,Ti‐oxide oxybarometer. Oxygen fugacities obtained cluster closely around the FMQ (Fayalite–Magnetite–Quartz) buffer (NWA998 = FMQ ? 0.8; Y‐000593 = FMQ ? 0.7; Nakhla = FMQ; Lafayette = FMQ + 0.1). The corresponding equilibration temperatures are 810 °C for Nakhla and Y‐000593, 780 °C for Lafayette and 710 °C for NWA998. All nakhlites record oxygen fugacities significantly higher and with a tighter range than those determined for Martian basalts, i.e., shergottites whose oxygen fugacities vary from FMQ ? 1 to FMQ ? 4. It has been known for some time that nakhlites are different from other Martian meteorites in chemistry, mineralogy, and crystallization age. The present study adds oxygen fugacity to this list of differences. The comparatively large variation in fO₂ recorded by shergottites was interpreted by Herd et al. (2002) as reflecting variable degrees of contamination with crustal fluids that would also carry a light rare earth element (REE)‐enriched component. The high oxygen fugacities and the large light REE enrichment of nakhlites fit qualitatively in this model. In detail, however, it is found that the inferred contaminating phase in nakhlites must have been different from those in shergottites. This is supported by unique ¹⁸²W/¹⁸⁴W and ¹⁴²Nd/¹⁴⁴Nd ratios in nakhlites, which are distinct from other Martian meteorites. It is likely that the differences in fO₂ between nakhlites and other Martian meteorites were established very early in the history of Mars. Parental trace element rich and trace element poor regions (reservoirs) of Mars mantle ( Brandon et al. 2000 ) must have been kept isolated throughout Martian history. Our results further show significant differences in closure temperature among the different nakhlites. The observed range in equilibration temperatures together with similar fO₂ values is attributable to crystallization of nakhlites in the same cumulate pile or lava layer at different burial depths from 0.5 to 30 m below the Martian surface in agreement with Mikouchi et al. (2003) and is further confirmed by similar crystallization ages of about 1.3 Ga ago (e.g., Misawa et al. 2003 ).