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Describes a type of high-power, high-voltage vacuum opening switch. Use of a Marx generator and pulse-forming elements in a liquid dielectric to generate high-voltage pulses; Problem with magnetic energy storage systems; Voltage-current characteristics of a reflex switch.

Many habitats in Europe have been managed by grazing for thousands of years. However, extensive grazing systems are becoming increasingly rare in the region, and there is a lack of understanding of the functioning of these systems. We carried out 147 structured interviews in 38 landscapes throughout the Carpathian Basin, with 3–5 informants/landscape. The number of actively grazing cattle, sheep and pigs, their year-round habitat use and the proportion of herds actively tended were documented for four characteristic historical periods (before, during and after socialist cooperatives and after EU Accession). The numbers of grazing cattle and sheep had decreased substantially by 2010 (by 71% and 49%, respectively), while pig grazing almost disappeared by the 1970s. Cattle primarily grazed habitats with taller vegetation. Sheep grazed dry pastures and stubbles, while pigs were driven into marshes and forests. In general, the importance of dry and wet grasslands increased, while the significance of marshes, stubble fields, vegetation along linear elements, second growth on hay meadows, wood-pastures and forests decreased over time. Approximately half of the grazed habitats were not typical pasture grasslands, and functioned as supplementary pastures during droughts, autumn and winter. The number of habitat types grazed per month per site dropped, and herding decreased substantially, in particular in the case of cattle and pigs. Contributing factors of the economic and social changes of the examined period included the collapse of the communist-era legal framework, the intensification of livestock husbandry, EU Common Agricultural Policy (CAP) regulations, and the rise of a nature conservation ethic. We conclude that agricultural policies should take into account the full spectrum of habitat types necessary for the effective operation of extensive grazing systems. We argue that conservation-oriented extensive grazing should use the traditional wisdom of herders but adapted to the present situations. [ABSTRACT FROM AUTHOR]

Habitat-based inventories provide critical reference data that are essential to track changes in amphibian communities and their habitats. We present the results of a pond inventory in a cultural landscape from central Romania. The presence/absence of amphibians was assessed through multiple-year surveys during the breeding season and larval development. Ten amphibian species and a species complex were identified: Triturus cristatus, T. vulgaris, Bombina variegata, Bufo bufo, B. viridis, Rana dalmatina, R. temporaria, R. arvalis, Hyla arborea, Pelobates fuscus and the R. esculenta complex. The species richness is larger in the permanent ponds than in the temporary ones. Rana dalmatina, B. bufo and the R. esculenta complex are the most frequent in the permanent ponds, while Bombina variegata and R. temporaria were the most common in temporary ponds. The scarcity of B. viridis and R. arvalis is explained by the lack of available habitats. Our data allow a more complex analysis of the spatial and temporal determinants of amphibian habitat use in this cultural landscape, and provide a consistent baseline for future surveys and monitoring programmes. [ABSTRACT FROM AUTHOR]

Background: A substantial proportion of patients with HIV infection will not respond to antiretroviral therapy. Early predictors of response to treatment are needed to identify patients who are at risk for treatment failure.Objective: To determine predictors of virologic and clinical response to indinavir, zidovudine, and lamivudine therapy.Design: Observational analysis of one treatment group in a phase III trial.Setting: 40 AIDS Clinical Trials units.Patients: 489 patients receiving indinavir, zidovudine, and lamivudine who had 1) a CD4 count of 0.200 x 10(9) cells/L or less after 8 or more weeks of study therapy and 2) plasma HIV-1 RNA measurements obtained at baseline and week 8.Measurements: HIV-1 RNA level and CD4 cell count at weeks 0, 4, 8, 24, and 40. Clinical progression was defined as a new AIDS-defining illness or death.Results: Patients' levels of HIV-1 RNA at the 8th study week of therapy predicted whether patients would achieve virologic suppression to below 500 (or 50) copies/mL at study week 24. An HIV-1 RNA level less than 500 copies/mL at week 24 was achieved in 71% of patients whose level at week 8 had been less than 500 copies/mL, 53% of those with a level of 500 copies/mL or more and at least 2-log(10) copies/mL reduction since baseline, 29% of those with a level of 500 copies/mL or more with a 1- to 1.99-log(10) copies/mL reduction, and 9% of those with a level of 500 copies/mL or greater and less than 1-log(10) copies/mL reduction since baseline (P < 0.001). HIV-1 RNA level at week 8 also predicted clinical progression. HIV-1 disease progressed in 2.2% of the patients with a week-8 HIV-1 RNA level less than 500 copies/mL, 2.3% of patients with 500 copies/mL or greater and at least 2-log(10) copies/mL reduction since baseline, 4.9% of patients with 500 copies/mL or greater and 1- to 1.99-log(10) copies/mL reduction since baseline, and 10.6% of patients with 500 copies/mL or greater and less than 1-log(10) copies/mL decrease since baseline (P = 0.009). After adjustment for HIV-1 RNA level, patients with a higher week-8 CD4 cell count were more likely to have a week-24 HIV-1 RNA level less than 500 copies/mL (relative risk for patients with a week-8 CD4 count >/= 0.10 x 10(9) cells/L, 1.47 [95% CI, 1.00 to 2.16] compared with <0.050 x 10(9) cells/L; relative risk for patients with a week-8 CD4 count of 0.05 to 0.099 x 10(9) cells/L, 0.98 [CI, 0.61 to 1.57] compared with <0.050 x 10(9) cells/L). After adjustment for HIV-1 RNA level, patients with a week-8 CD4 count of 0.05 x 10(9) cells/L or greater (compared with <0.05 x 10(9) cells/L) had a decreased hazard for clinical progression (hazard ratio, 0.25 [CI, 0.09 to 0.67]).Conclusions: The HIV-1 RNA level and CD4 cell count achieved at 8 weeks of treatment are important predictors of subsequent virologic and clinical outcomes. [ABSTRACT FROM AUTHOR]

Background and Objectives: Among the various treatment modalities for condyloma acuminatum, excisional cold-blade surgery appears excellent but it has been little studied and little used, particularly for lesions not located in the perianal area.Goals: To examine the efficacy and complications of scissors excision of single anogenital warts.Study Design: Retrospective analysis of single warts completely excised with scissors for the purpose of biopsy before patient entry in a randomized, placebo-controlled study of the efficacy and safety of various parenteral interferons in combination with cryotherapy.Results: Of 152 patients entered in the main study, 85 patients were available for analysis. At 4 and 16 weeks after excision, 16 of 85 (19%) and 14 of 68 (21%) of the excised lesions recurred. After at 6 least months of follow-up, 2 of 11 (18%) of the excision sites demonstrated some evidence of pigmentation changes.Conclusions: Scissors excision of single anogenital warts has a high rate of success and acceptable long-term side-effects. [ABSTRACT FROM AUTHOR]