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Early in 1992, Bangladesh experienced an influx of Burmese refugees, reaching a total of 263,000 by May. As the health and nutritional status of the refugee population was reportedly poor, a need was felt to collect dependable data through epidemiological surveillance, on which interventions could be based. The nutritional and health status of children was dramatically poor in all camps surveyed and a deterioration was expected in the coming monsoon. Several problem areas could be identified. Based on these findings it was possible to undertake appropriate action and to avert threatening calamities. Epidemiological surveillance is an important monitoring tool to provide reliable data on the health and nutritional status of refugee populations and to help the organizations involved to prioritize and evaluate their actions.  相似文献   
2.
Abstract: The effects of human activities in forests are often examined in the context of habitat conversion. Changes in habitat structure and composition are also associated with increases in the activity of people with vehicles and equipment, which results in increases in anthropogenic noise. Anthropogenic noise may reduce habitat quality for many species, particularly those that rely on acoustic signals for communication. We compared the density and occupancy rate of forest passerines close to versus far from noise‐generating compressor stations and noiseless well pads in the boreal forest of Alberta, Canada. Using distance‐based sampling, we found that areas near noiseless energy facilities had a total passerine density 1.5 times higher than areas near noise‐producing energy sites. The White‐throated Sparrow (Zonotrichia albicollis), Yellow‐rumped Warbler (Dendroica coronata), and Red‐eyed Vireo (Vireo olivaceus) were less dense in noisy areas. We used repeat sampling to estimate occupancy rate for 23 additional species. Seven had lower conditional or unconditional occupancy rates near noise‐generating facilities. One‐third of the species examined showed patterns that supported the hypothesis that abundance is influenced by anthropogenic noise. An additional 4 species responded negatively to edge effects. To mitigate existing noise impacts on birds would require approximately $175 million. The merits of such an effort relative to other reclamation actions are discussed. Nevertheless, given the $100 billion energy‐sector investment planned for the boreal forest in the next 10 years, including noise suppression technology at the outset of construction, makes noise mitigation a cost‐effective best‐management practice that might help conserve high‐quality habitat for boreal birds.  相似文献   
3.
Tropical forest ecosystems are threatened by habitat conversion and other anthropogenic actions. Timber production forests can augment the conservation value of primary forest reserves, but studies of logging effects often yield contradictory findings and thus inhibit efforts to develop clear conservation strategies. We hypothesized that much of this variability reflects a common methodological flaw, simple pseudoreplication, that confounds logging effects with preexisting spatial variation. We reviewed recent studies of the effects of logging on biodiversity in tropical forests (n = 77) and found that 68% were definitively pseudoreplicated while only 7% were definitively free of pseudoreplication. The remaining proportion could not be clearly categorized. In addition, we collected compositional data on 7 taxa in 24 primary forest research plots and systematically analyzed subsets of these plots to calculate the probability that a pseudoreplicated comparison would incorrectly identify a treatment effect. Rates of false inference (i.e., the spurious detection of a treatment effect) were >0.5 for 2 taxa, 0.3–0.5 for 2 taxa, and <0.3 for 3 taxa. Our findings demonstrate that tropical conservation strategies are being informed by a body of literature that is rife with unwarranted inferences. Addressing pseudoreplication is essential for accurately assessing biodiversity in logged forests, identifying the relative merits of specific management practices and landscape configurations, and effectively balancing conservation with timber production in tropical forests. Pseudoreplicación en Bosques Tropicales y Efectos Resultantes Sobre la Conservación de Biodiversidad  相似文献   
4.
Scale, Variable Density, and Conservation Planning for Mammalian Carnivores   总被引:2,自引:0,他引:2  
Abstract: Many mammalian carnivores are in local or global decline. To slow this process, continued planning to protect these species is warranted, Still, the data bases that we have at our disposal do not adequately document population requirements for space at scales appropriate for conservation planning. To illustrate this problem, we have collected published data for 214 population censuses of carnivores. We tested for a relationship between the number of individuals censused and the size of study site for our entire data set. We conducted the same test for each family, for which we obtained sufficient and qualifying census data With areas ranging from less than 10 km2 to over 40,000 km2, we obtained a significant regression (p < .001; r2= 76%) for the sample as a whole. We examined the distribution of densities with increasing area and found that the relationship was not constant but decreased We noticed that numbers per census-area size increased with a slope (m < 1). We also noticed that the sizes of study areas were unevenly distributed Only 7% of the studies in our sample censused regions larger than 10,000 km2. It remains unclear to what extent and how the density decreases with increasing scale We expect that extrapolations from small scales to larger ones are likely to underestimate space requirements for carnivores.  相似文献   
5.
Biofilm fermentation is a newly developed promising technique in fermentation technology. In this study no.3 and no.3S media have been used for the lipopeptide antibiotic iturin A production by Bacillus subtilis RB14. The main component of no.3 and no.3S media is Polypepton and Polypepton S, respectively. B. subtilis RB14 produces thick stable biofilm and high amount of iturin A in no.3S medium. Whereas, impaired biofilm formation and lower iturin A production was observed in no.3 medium. From the analytical information it was observed that the amounts of metal ions, such as K+, Ca2+ and Mn2+, cysteine and cellulose are lower in Polypepton compared to the Polypepton S. To investigate their effect on biofilm formation and iturin A production cysteine, cellulose, K+, Ca2+ and Mn2+ were added respectively into the no.3 medium at similar amount that Polypepton S contains. It was observed that individual addition of K+, Ca2+, cysteine and cellulose had no effect on biofilm formation, cellular growth induction or iturin A production. However, when Mn2+ was supplemented in no.3 medium, biofilm development was restored with an improved production of iturin A. Finally, combined addition of investigated substances into the no.3 medium resulted with highly folded, thick biofilm with high cellular growth and iturin A production compared to the original no.3 medium.  相似文献   
6.
In biofilm fermentation, from the very early moments, surfactin was produced along with the biofilm development in the lipopeptide antibiotic production medium by using Bacillus subtilis. However, almost no iturin A was produced in its first 24 hours of cultivation and the production of iturin A began much later. Volumes of the nutrient medium and available surface area of the biofilm reactors were found to be important with the relative production of these two antibiotics. Production of iturin A was increased from 12 mg to about 50 mg per reactor when the culture size was increased from 5 mL to 20 mL, as the depth of the medium was increased. The production level was saturated thereafter with larger volumes. On the other hand, surfactin production was remained similar, which was about 10 mg per reactor, from all the 5 mL to 80 mL of biofilm culture. Optimized temperature for iturin A and surfactin production was observed at 25 and 37°C, respectively. In the biofilm fermentation, production of surfactin was increased when the incubation temperature was increased within the temperature range of 25 to 37°C, on the other hand, iturin A production was gradually decreased with the increase of the incubation temperature.  相似文献   
7.
Malt residue is a common waste or byproduct from beer industries after brewing and milling of malted barley. In this work, Bacillus subtilis RB14 was used to study the microbial growth and production of secondary metabolites like lipopeptide antibiotic iturin A in the malt residue for its effective recycling. B. subtilis RB14 could grow in submerged fermentation of malt residue and significant growth (109 CFU/mL) was observed without any supplementation. In submerged fermentation iturin A production using malt residue was about 170 mg/L, which was found to be higher than its production in No.3 (Polypepton, glucose, KH2PO4, MgSO4·7H2O) medium where production was about 120 mg/L. More than 600 mg/L of iturin A production was observed when malt residue was combinedly used with No.3 medium. This production was significantly higher than their summation of their individual production. However, the growth of B. subtilis in combined medium was found to be similar to that of the submerged fermentation in simple malt residue. Therefore, the remarkable enhancement in production of iturin A in supplemented malt residue was attributed to the nutrients supplied from No.3 medium.  相似文献   
8.
Iturin A is a cyclic lipopeptide antibiotic and eight different kinds of iturin A have been reported based on its alkyl side chains. As iturin A is a promising biocontrol agent, total production of iturin A was tried to enhance and comparative production of its homologues was investigated by using different nitrogen and carbon sources. When Polypepton S and defatted soybean meal were used, total production as well as the ratio of the iturin A homologues were similar. However, production of iturin A was relatively lower and also the ratio of the iturin A homologues was different when Polypepton was used, where A2 was decreased and A4 was increased. Production ratio of the iturin A homologues was similar for the carbon sources like maltose, mannitol, sucrose and starch but relative production of iturin A2 was much enhanced compared to A3 when lactose or galactose was used. Interestingly production ratio of A4 was increased and A2 and A3 were decreased when no additional carbon source was used, and similar tendency was observed in the homologue ratio with glucose and fructose. Production of iturin A homologue A6 was significantly increased whereas A2 and A3 were decreased when defatted rapeseed cake was used. Utilization of different amino acids did not show significant differences in their production of the iturin A homologues. Oxygen supply found to be the factor affecting the production of iturin A homologues when it was investigated in a varied culture volume size and shaking speed. A2 found to be increased with increased oxygen supply where the production of A3 was affected inversely.  相似文献   
9.
A new solid state fermentation reactor (SSFR) for solid substrate was used for the production of lipopeptide antibiotic iturin A using Bacillus subtilis RB14-CS. Solid state fermentation (SSF) is the technique of cultivation of microorganisms on solid and moist substrates in the absence of free water. SSF has shown much promise in the development of several bioprocesses and products because of their several advantages like absence of free water that allows simplified downstream processing and low cost. SSFR allows agitation of the SSF culture with improved temperature control and air supply. Interestingly, when okara, the widely available waste product from the tofu industries, was used as the solid substrate for the SSFR, no iturin A production was observed. However, without agitation, production of iturin A was observed in the SSFR but the production level remained low. The low production of iturin A was found to be due to the heat generation and excess temperature rise inside the reactor system during the fermentation process. Maintaining the temperature within a range of 25–30°C, production of iturin A was significantly improved in the SSFR. This was comparable to the laboratory scale production, and signifies the potential application of the SSFR for SSF.  相似文献   
10.
Economic and Ecological Outcomes of Flexible Biodiversity Offset Systems   总被引:1,自引:0,他引:1  
The commonly expressed goal of biodiversity offsets is to achieve no net loss of specific biological features affected by development. However, strict equivalency requirements may complicate trading of offset credits, increase costs due to restricted offset placement options, and force offset activities to focus on features that may not represent regional conservation priorities. Using the oil sands industry of Alberta, Canada, as a case study, we evaluated the economic and ecological performance of alternative offset systems targeting either ecologically equivalent areas (vegetation types) or regional conservation priorities (caribou and the Dry Mixedwood natural subregion). Exchanging dissimilar biodiversity elements requires assessment via a generalized metric; we used an empirically derived index of biodiversity intactness to link offsets with losses incurred by development. We considered 2 offset activities: land protection, with costs estimated as the net present value of profits of petroleum and timber resources to be paid as compensation to resource tenure holders, and restoration of anthropogenic footprint, with costs estimated from existing restoration projects. We used the spatial optimization tool MARXAN to develop hypothetical offset networks that met either the equivalent‐vegetation or conservation‐priority targets. Networks that required offsetting equivalent vegetation cost 2–17 times more than priority‐focused networks. This finding calls into question the prudence of equivalency‐based systems, particularly in relatively undeveloped jurisdictions, where conservation focuses on limiting and directing future losses. Priority‐focused offsets may offer benefits to industry and environmental stakeholders by allowing for lower‐cost conservation of valued ecological features and may invite discussion on what land‐use trade‐offs are acceptable when trading biodiversity via offsets. Resultados Económicos y Ecológicos de Sistemas de Compensación de Biodiversidad Flexible Habib et al.  相似文献   
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