943 resultados para Schubert, Otto.
Resumo:
In this report we analyze the Topic 5 report’s recommendations for reducing nitrogen losses to the Gulf of Mexico (Mitsch et al. 1999). We indicate the relative costs and cost-effectiveness of different control measures, and potential benefits within the Mississippi River Basin. For major nonpoint sources, such as agriculture, we examine both national and basin costs and benefits. Based on the Topic 2 economic analysis (Diaz and Solow 1999), the direct measurable dollar benefits to Gulf fisheries of reducing nitrogen loads from the Mississippi River Basin are very limited at best. Although restoring the ecological communities in the Gulf may be significant over the long term, we do not currently have information available to estimate the benefits of such measures to restore the Gulf’s long-term health. For these reasons, we assume that measures to reduce nitrogen losses to the Gulf will ultimately prove beneficial, and we concentrate on analyzing the cost-effectiveness of alternative reduction strategies. We recognize that important public decisions are seldom made on the basis of strict benefit–cost analysis, especially when complete benefits cannot be estimated. We look at different approaches and different levels of these approaches to identify those that are cost-effective and those that have limited undesirable secondary effects, such as reduced exports, which may result in lost market share. We concentrate on the measures highlighted in the Topic 5 report, and also are guided by the source identification information in the Topic 3 report (Goolsby et al. 1999). Nonpoint sources that are responsible for the bulk of the nitrogen receive most of our attention. We consider restrictions on nitrogen fertilizer levels, and restoration of wetlands and riparian buffers for denitrification. We also examine giving more emphasis to nitrogen control in regions contributing a greater share of the nitrogen load.
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We have studied the reproductive biology of the goldlined seabream (Rhabdosargus sarba) in the lower Swan River Estuary in Western Australia, focusing particularly on elucidating the factors influencing the duration, timing, and frequency of spawning and on determining potential annual fecundity. Our results demonstrate that 1) Rhabdosargus sarba has indeterminate fecundity, 2) oocyte hydration commences soon after dusk (ca. 18:30 h) and is complete by ca. 01:30−04:30 h and 3) fish with ovaries containing migratory nucleus oocytes, hydrated oocytes, or postovulatory follicles were caught between July and November. However, in July and August, their prevalence was low, whereas that of fish with ovaries containing substantial numbers of atretic yolk granule oocytes was high. Thus, spawning activity did not start to peak until September (early spring), when salinities were rising markedly from their winter minima. The prevalence of spawning was positively correlated with tidal height and was greatest on days when the tide changed from flood to ebb at ca. 06:00 h, i.e., just after spawning had ceased. Because our estimate of the average daily prevalence of spawning by females during the spawning season (July to November) was 36.5%, individual females were estimated to spawn, on average, at intervals of about 2.7 days and thus about 45 times during that period. Therefore, because female R. sarba with total lengths of 180, 220, and 260 mm were estimated to have batch fecundities of about 4500, 7700, and 12,400 eggs, respectively, they had potential annual fecundities of about 204,300, 346,100 and 557,500 eggs, respectively. Because spawning occurs just prior to strong ebb tides, the eggs of R. sarba are likely to be transported out of the estuary into coastal waters where salinities remain at ca. 35‰. Such downstream transport would account for the fact that, although R. sarba exhibits substantial spawning activity in the lower Swan River Estuary, few of its early juveniles are recruited into the nearshore shallow waters of this estuary.
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The relative abundance of Bristol Bay red king crab (Paralithodes camtschaticus) is estimated each year for stock assessment by using catch-per-swept-area data collected on the Alaska Fisheries Science Center’s annual eastern Bering Sea bottom trawl survey. To estimate survey trawl capture efficiency for red king crab, an experiment was conducted with an auxiliary net (fitted with its own heavy chain-link footrope) that was attached beneath the trawl to capture crabs escaping under the survey trawl footrope. Capture probability was then estimated by fitting a model to the proportion of crabs captured and crab size data. For males, mean capture probability was 72% at 95 mm (carapace length), the size at which full vulnerability to the survey trawl is assigned in the current management model; 84.1% at 135 mm, the legal size for the fishery; and 93% at 184 mm, the maximum size observed in this study. For females, mean capture probability was 70% at 90 mm, the size at which full vulnerability to the survey trawl is assigned in the current management model, and 77% at 162 mm, the maximum size observed in this study. The precision of our estimates for each sex decreased for juveniles under 60 mm and for the largest crab because of small sample sizes. In situ data collected from trawl-mounted video cameras were used to determine the importance of various factors associated with the capture of individual crabs. Capture probability was significantly higher when a crab was standing when struck by the footrope, rather than crouching, and higher when a crab was hit along its body axis, rather than from the side. Capture probability also increased as a function of increasing crab size but decreased with increasing footrope distance from the bottom and when artificial light was provided for the video camera.
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We report a facile strategy to tether lanthanide complexes to organic-inorganic hybrid titania materials via sol-gel processing by employing chemically modified titanium alkoxide as the precursor where the organic ligand sensitizing the luminescence of lanthanide ions is bonded to titanium.
Resumo:
Background: HIV infection leads to a decreasing immune response, thereby facilitating the appearance of other infections, one of the most important ones being HPV. However, studies are needed for determining associations between immunodeficiency caused by HIV and/or the presence of HPV during the course of cervical lesions and their degree of malignancy. This study describes the cytological findings revealed by the Papanicolaou test, laboratory characteristics and HPV molecular profile in women with and without HIV infection. Methods: A total of 216 HIV-positive and 1,159 HIV-negative women were invited to participate in the study; PCR was used for the molecular detection of HPV in cervical samples. Statistical analysis (such as percentages, Chi-square test and Fisher's exact test when applicable) determined human papillomavirus (HPV) infection frequency (single and multiple) and the distribution of six types of high-risk-HPV in women with and without HIV infection. Likewise, a logistic regression model was run to evaluate the relationship between HIV-HPV infection and different risk factors. Results: An association was found between the frequency of HPV infection and infection involving 2 or more HPV types (also known as multiple HPV infection) in HIV-positive women (69.0% and 54.2%, respectively); such frequency was greater than that found in HIV-negative women (44.3% and 22.7%, respectively). Statistically significant differences were observed between both groups (p = 0.001) regarding HPV presence (both in infection and multiple HPV infection). HPV-16 was the most prevalent type in the population being studied (p = 0.001); other viral types had variable distribution in both groups (HIV-positive and HIV-negative). HPV detection was associated with <500 cell/mm(3) CD4-count (p = 0.004) and higher HIV-viral-load (p = 0.001). HPV-DNA detection, <200 cell/mm(3) CD4-count (p = 0.001), and higher HIV-viral-load (p = 0.001) were associated with abnormal cytological findings. Conclusions: The HIV-1 positive population in this study had high multiple HPV infection prevalence. The results for this population group also suggested a greater association between HPV-DNA presence and cytological findings. HPV detection, together with low CD4 count, could represent useful tools for identifying HIV-positive women at risk of developing cervical lesions.
Resumo:
Estetyka w archeologii. Antropomorfizacje w pradziejach i starożytności, eds. E. Bugaj, A. P. Kowalski, Poznań: Wydawnictwo Poznańskie.
Resumo:
http://www.archive.org/details/bordenesreligiosas01maasrich/