Building a case against economic development

Although development is widely held to be the solution to poverty in the Third World, a case can be made that it is a part of the problem. It is commonly believed that development eradicates poverty through increased production of goods and services, but the past history of that activity also contains an unacknowledged history of socially-constructed scarcity. Poverty is a form of development-induced scarcity caused by the playing out of production relations located within a nexus of interacting technical, social, political, cultural, ecological, and academic relations. In that sense poverty is caused by multiple forces acting within a discursive materialist formation. We have used an analytical framework called the nexus of production relations to elucidate these ideas. This framework also suggests that the opportunities available to the poor for meeting their needs are far more varied and numerous than theories of economic development would have us believe.     

养殖对虾细菌性红体病的初步研究

从海南琼山患红体病的养殖南美白对虾(Penaeus vannamei)的肝胰脏和肌肉中分离出2株细菌，经纯化培养后的人工感染结果表明，该2株菌均为引起对虾红体病的细菌性病原菌；根据对这2株菌的形态及生理生化特征检测结果，确定这2株菌分别为溶藻弧菌(Vibrioalginolyticus)和副溶血弧菌(V.parahaemolyticus)。药敏试验表明，氮霉素、链霉素和庆大霉素等7种抗生素对抑制这2种致病菌具有良好作用。     

Apparent lack of CYP1A response to high PCB body burdens in fish from a chronically contaminated PCB site

Chronic exposure to organic contaminants such as polychlorinated biphenyls (PCBs) can lead to the development of resistance to these chemicals, a condition associated with reduced response of CYP1A1, a pollutant-inducible biomarker. We measured CYP1A activity (ethoxyresorufin o-deethylase, EROD) and PCB concentrations in feral fish from the Town Branch/Mud River system (Logan County, KY), a stream historically contaminated with PCBs and partially remediated. As a first step in evaluating the possible development of resistant populations in this system, we measured CYP1A expression and PCB body burdens in resident fish from sites we previously characterized as containing biologically significant levels of CYP1A inducing compounds. Mean PCB concentrations in edible flesh ranged from 75.2 to 16.7 microg/g in fish collected from Town Branch remediated sites and were relatively low (1.23 microg/g) in Town Branch reference site fish. However, hepatic CYP1A activity was similar among individuals of most species collected from reference and contaminated/remediated sites. The absence of elevated CYP1A levels in resident fish species despite the presence of significant PCB body burdens may indicate these fish have developed reduced sensitivity to CYP1A induction, a condition associated with acquired resistance to toxicants.     

广西北海湾COD与水文生物要素及不同形态氮磷的关系

本文探讨了北海深COD值的分布特征及其与水文，生物要素及不同形态氮，磷含量的关系，结果表明；河流输入对本湾COD值的影响突出表现在春、夏季、冬季最小，秋季则以沿岸排废，排污影响为主，水文要素对COD值的分布起主导控制作用，生物化学作用仅占次要地位；春、夏、冬三个季度月COD值与氮含量的相关性较为显著，秋季则与磷含量的相关性较为显著。     

Fast diffusion along mobile grain boundaries in calcite

Experimental measurements of grain boundary diffusion are usually conducted on static boundaries, despite the fact that grain boundaries deep in the Earth are frequently mobile. In order to explore the possible effect of boundary mobility on grain boundary diffusion rates we have measured the uptake of ⁴⁴Ca from a layer of ⁴⁴Ca-enriched calcite powder during the static recrystallization of a single crystal of calcite at 900°C. A region about 500 μm wide adjacent to the powder layer is heterogeneously enriched in ⁴⁴Ca, and complex zoning patterns, including sharp steps in composition and continuous increases and decreases in ⁴⁴Ca content, are developed. In metamorphic rocks, these would normally be interpreted in terms of changes in pressure or temperature, Rayleigh fractionation, or episodic fluid infiltration. These explanations cannot apply to our experiments, and instead the zoning patterns are interpreted as being due to variations in grain boundary migration rate. We have applied an analytical model which allows the product of grain boundary diffusion coefficient and grain boundary width (D _GB δ) to be calculated from the grain boundary migration rate and the compositional gradient away from the powder layer. The value of D _GB δ in the mobile grain boundaries is at least five orders of magnitude greater than the published value for static boundaries under the same conditions. In order to allow the scale of chemical equilibrium (and hence textural evolution) to be predicted under both experimental and geological conditions, we present quantitative diffusion-regime maps for static and mobile boundaries in calcite, using both published values and our new values for grain boundary diffusion in mobile boundaries. Enhanced diffusion in mobile boundaries has wide implications for the high temperature rheology of Earth materials, for geochronology, and for interpretations of the length- and time-scales of chemical mass-transport. Moreover, zones of anomalously high electrical conductivity in the crust and mantle could be regions undergoing recrystallization such as active shear zones, rather than regions of anomalous mineralogy, water- or melt-content as is generally suggested.     

带压开采煤层底板的承压能力研究

通过实测资料揭示了煤层底板保护层在一定条件下存在导水和贮水的性能,并剖析了这种性能的水理性质和规律,阐明了起始水力梯度、消压强度、抗水压强度、临界突水系数在概念上的统一性;在此基础上,分析了煤矿突水的机理与模式;并指明了探测研究保护层这一特性在确定开采煤层底板抗水压能力和带压开采安全性等方面的重要意义。     

Towards quantifying uncertainty in transient climate change

Ensembles of coupled atmosphere–ocean global circulation model simulations are required to make probabilistic predictions of future climate change. “Perturbed physics” ensembles provide a new approach in which modelling uncertainties are sampled systematically by perturbing uncertain parameters. The aim is to provide a basis for probabilistic predictions in which the impact of prior assumptions and observational constraints can be clearly distinguished. Here we report on the first perturbed physics coupled atmosphere–ocean model ensemble in which poorly constrained atmosphere, land and sea-ice component parameters are varied in the third version of the Hadley Centre model (the variation of ocean parameters will be the subject of future study). Flux adjustments are employed, both to reduce regional sea surface temperature (SST) and salinity biases and also to admit the use of combinations of model parameter values which give non-zero values for the global radiation balance. This improves the extent to which the ensemble provides a credible basis for the quantification of uncertainties in climate change, especially at a regional level. However, this particular implementation of flux-adjustments leads to a weakening of the Atlantic overturning circulation, resulting in the development of biases in SST and sea ice in the North Atlantic and Arctic Oceans. Nevertheless, model versions are produced which are of similar quality to the unperturbed and un-flux-adjusted version. The ensemble is used to simulate pre-industrial conditions and a simple scenario of a 1% per year compounded increase in CO₂. The range of transient climate response (the 20 year averaged global warming at the time of CO₂ doubling) is 1.5–2.6°C, similar to that found in multi-model studies. Measures of global and large scale climate change from the coupled models show simple relationships with associated measures computed from atmosphere-mixed-layer-ocean climate change experiments, suggesting that recent advances in computing the probability density function of climate change under equilibrium conditions using the perturbed physics approach may be extended to the transient case.     

An analysis of short-term albedo variations at Haut Glacier d'Arolla, Switzerland

Abstract An analysis of ten‐minute albedo variations, recorded on Haut Glacier d'Arolla, Switzerland, over an 11 day period in the 1999 ablation season is presented. Most of the short‐term (<1 day) albedo variability is caused by variations in cloud cover, while solar zenith angle variations in the range 25° to 75° are of minor importance, probably due to the predominantly cloudy conditions during the measurement period. A new method to calculate albedo variation as a function of cloud cover is developed. Short‐term albedo variations are expressed by the ratio of the measured albedo to the daily albedo ‘minimum’, defined as the albedo under cloud‐free conditions when the solar zenith angle is <50°. Variations in cloud cover are quantified by the ratio of the measured incoming shortwave radiation flux to the theoretical direct‐beam shortwave radiation flux. The resulting relationships are successful, explaining 83% and 87–90% of short‐term albedo variation on snow and ice respectively, and may be incorporated into albedo parameterizations already used in numerical energy balance melt models, without the need for additional data. Simulations with a glacier energy balance model suggest that melt rates are overestimated by between 1 and 3 mm water equivalent per day if a correction is not made for the increase in albedo under cloudy conditions. Other causes of albedo variation are identified and evidence is found for the removal of fine debris from the glacier surface by intense rainfall, leading to an albedo increase. The implications for energy balance models and satellite‐derived albedo measurements are discussed.