1,317 research outputs found

    Experimental investigation of the excess charge and time constant of minority carriers in the thin diffused layer of 0.1 ohm-cm silicon solar cells

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    An experimental method is presented that can be used to interpret the relative roles of bandgap narrowing and recombination processes in the diffused layer. This method involves measuring the device time constant by open-circuit voltage decay and the base region diffusion length by X-ray excitation. A unique illuminated diode method is used to obtain the diode saturation current. These data are interpreted using a simple model to determine individually the minority carrier lifetime and the excess charge. These parameters are then used to infer the relative importance of bandgap narrowing and recombination processes in the diffused layer

    Monitoring of organochlorine pesticide residues from bovine milk in Patna (Bihar), INDIA

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     The milk has high nutritional properties and is widely used as baby food in different forms. The present study was undertaken to evaluate pesticide contamination in bovine milk samples from Patna district of Bihar. Out of 24 samples analyzed during 2012, 18 samples (75 %) were found to be contaminated with HCH residues varying from ND-0.178 mg kg-1 (mean value 0.135 mg kg-1). Seven samples (29.2 %) had HCH exceeding MRL of 0.01 mg kg-1. DDT residues were detected in 20 samples (83.3 %) and ranged from ND-0.132 mg kg-1 (mean value 0.122 mg kg-1). Five samples (20.8 %) contained DDT residues above the prescribed MRL of 0.05 mg kg-1. Out of 24 samples of bovine milk analyzed during 2013, 16 samples (66.7 %) were found to be contaminated with HCH and 15 samples (62.5%) with DDT residues. The residues of HCH varied from ND-0.154 mg kg-1 (mean value 0.053 mg kg-1) and DDT from ND-0.120 mg kg-1 (mean value 0.122 mg kg-1). The residues of HCH and DDT were above MRL in four samples (16.7 %) and three samples (12.5 %) respectively. The management practices of animals and legal punishment on using banned pesticides are the alternatives to reduce pesticide contamination incidences in milk

    On the Road to Sustainability? A Review of a Half-Century of Biodiversity Conservation Successes in Nepal and Some Thoughts on Future Needs

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    We review the history, over the past half-century, of biodiversity conservation legislation and programs in Nepal. We especially consider how they have evolved in light of some earlier concerns resulting from, for example, the strict “fines and fences” conservation approaches first implemented in the 1970s, to pressing issues that emerged over time such as park-people and wildlife-human conflicts, poaching and illegal wildlife trade. We also consider how the implementation of international conservation agreements and demographic and political changes have affected conservation programs in Nepal. We finish by discussing conservation in the context of sustainable development and conclude with some thoughts on future research and managerial needs in a rapidly-changing world

    Fluctuation induces evolutionary branching in a modeled microbial ecosystem

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    The impact of environmental fluctuation on species diversity is studied with a model of the evolutionary ecology of microorganisms. We show that environmental fluctuation induces evolutionary branching and assures the consequential coexistence of multiple species. Pairwise invasibility analysis is applied to illustrate the speciation process. We also discuss how fluctuation affects species diversity.Comment: 4 pages, 4 figures. Submitted to Physical Review Letter

    A cross-cultural comparison of the link between modernization, anthropomorphism and attitude to wildlife

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    Anthropogenic pressure has significantly increased in the last decades, often enhancing conflicts at the humanndash;wildlife interface. Therefore, understanding peoplesrsquo; value orientations, attitudes and behavioural intentions towards wildlife is a crucial endeavour to reduce the occurrence of conflicts between humans and wildlife. Previous research in the USA has shown a consistent link between modernization and increased anthropomorphism (i.e., the tendency to attribute human mental or physical characteristics to other entities), leading to positive changes in value orientations, attitudes, and behavioural intentions towards wildlife. In this paper, we aimed to address whether this link is also present in other cultures, by testing participants (N = 741) in five different countries (Brazil, Indonesia, Malaysia, Mexico, and Spain). Our study shows that while the positive link between anthropomorphism, positive attitudes and behavioural intentions towards wildlife is universal, the link between modernization and anthropomorphism is culturally mediated. In some countries (Indonesia, Malaysia, Spain), modernization increased anthropomorphism, while in others modernization predicted no differences (Brazil) or even a decrease in anthropomorphism (Mexico), ultimately deteriorating individualsrsquo; attitude and behavioural intentions towards wildlife. These results call for caution when generalizing findings from western industrialized countries to inform conservation policies worldwide

    Approximate Hermitian-Yang-Mills structures and semistability for Higgs bundles. II: Higgs sheaves and admissible structures

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    We study the basic properties of Higgs sheaves over compact K\"ahler manifolds and we establish some results concerning the notion of semistability; in particular, we show that any extension of semistable Higgs sheaves with equal slopes is semistable. Then, we use the flattening theorem to construct a regularization of any torsion-free Higgs sheaf and we show that it is in fact a Higgs bundle. Using this, we prove that any Hermitian metric on a regularization of a torsion-free Higgs sheaf induces an admissible structure on the Higgs sheaf. Finally, using admissible structures we proved some properties of semistable Higgs sheaves.Comment: 18 pages; some typos correcte

    Effect of Hydrologic Restoration on the Habitat of The Cape Sable Seaside Sparrow, Annual Report of 2003-2004

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    Following on our previous year’s work on ‘Effect of hydrologic restoration on the habitat of the Cape Sable seaside sparrow (CSSS)’, we presented first year results at the Cape Sable seaside sparrow – fire planning workshop at Everglades National Park in December 2003. Later, with almost the same set of crews as in the previous year, we started field work in the first week of January and continued till May 26, 2004. Protocols for sampling topography and vegetation in 2004 were identical to the previous year. In the early season, we completed topographic surveys along two remaining transects, B and E (~16.5 km), and vegetation surveys along three transects, D, E and F (~10.8 km), leaving only the vegetation sampling on transects B and C to be completed in 2005. During April and May, vegetation sampling was completed at 230 census sites, making the total of 409 CSSS census sites for which we have complete vegetation data. We updated data sets from both 2003 and 2004, and analyzed them together using cluster analysis, ordination, weighted-averaging regression and analysis of variance, as we had in 2003. Additionally, we used logistic regression to examine the effect of vegetation structural parameters on the recent occurrence of CSSS. We also analyzed vegetation observations recorded by the sparrow census team in 1981 and annually between 1992 and 2004 to assess historical patterns of vegetation change in CSSS habitat

    Effect of Hydrologic Restoration on the Habitat of The Cape Sable Seaside Sparrow, Annual Report of 2002-2003

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    After developing field sampling protocols and making a series of consultations with investigators involved in research in CSSS habitat, we determined that vegetationhydrology interactions within this landscape are best sampled at a combination of scales. At the finer scale, we decided to sample at 100 m intervals along transects that cross the range of habitats present, and at the coarser scale, to conduct an extensive survey of vegetation at sites of known sparrow density dispersed throughout the range of the CSSS. We initiated sampling in the first week of January 2003 and continued it through the last week of May. During this period, we established 6 transects, one in each CSSS subpopulation, completed topographic survey along the Transects A, C, D, and F, and sampled herb and shrub stratum vegetation, soil depth and periphyton along Transects A, and at 179 census points. We also conducted topographic surveys and completed vegetation and soil depth sampling along two of five transects used by ENP researchers for monitoring long-term vegetation change in Taylor Slough. We analyzed the data by summarizing the compositional and structural measures and by using cluster analysis, ordination, weighted averaging regression, and weighted averaging calibration. The mean elevation of transects decreased from north to south, and Transect F had greater variation than other transects. We identified eight vegetation assemblages that can be grouped into two broad categories, ‘wet prairie’ and ‘marsh’. In the 2003 survey, wet prairies were most dominant in the northeastern sub-populations, and had shorter inferred-hydroperiod, higher species richness and shallower soils than marshes, which were common in Subpopulations A, D, and the southernmost regions of Sub-population B. Most of the sites at which birds were observed during 2001 or 2002 had an inferred-hydroperiod of 120-150 days, while no birds were observed at sites with an inferred-hydroperiod less than 120 days or more than 300 days. Management-induced water level changes in Taylor Slought during the 1980’s and 1990’s appeared to elicit parallel changes in vegetation. The results described in detail in the following pages serve as a basis for evaluating and modifying, if necessary, the sampling design and analytical techniques to be used in the next three years of the project

    Effect of Hydrologic Restoration on the Habitat of The Cape Sable Seaside Sparrow, Annual Report of 2004-2005

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    The major activities in Year 3 on ‘Effect of hydrologic restoration on the habitat of the Cape Sable seaside sparrow (CSSS)’ included presentations, field work, data analysis, and report preparation. During this period, we made 4 presentations, two at the CSSS – fire planning workshops at Everglades National Park (ENP), one at the Society of Wetland Scientists’ meeting in Charleston, SC, and a fourth at the Marl Prairie/CSSS performance measure workshop at ENP. We started field work in the third week of January and continued till June 3, 2005. Early in the field season, we completed vegetation surveys along two transects, B and C (~15.1 km). During April and May, vegetation sampling was completed at 199 census sites, bringing to 608 the total number of CSSS census sites with quantitative vegetation data. We updated data sets from all three years, 2003-05, and analyzed them using cluster analysis and ordination as in previous two years. However, instead of weighted averaging, we used weighted-averaging partial least square regression (WA-PLS) model, as this method is considered an improvement over WA for inferring values of environmental variables from biological species composition. We also validated the predictive power of the WA-PLS regression model by applying it to a sub-set of 100 census sites for which hydroperiods were “known” from two sources, i.e., from elevations calculated from concurrent water depth measurements onsite and at nearby water level recorders, and from USGS digital elevation data. Additionally, we collected biomass samples at 88 census sites, and determined live and dead aboveground plant biomass. Using vegetation structure and biomass data from those sites, we developed a regression model that we used to predict aboveground biomass at all transects and census sites. Finally, biomass data was analyzed in relation to hydroperiod and fire frequency
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