Significance of durability of mineral fibers for their toxicity and carcinogenic potency in the abdominal cavity of rats in comparison with the low sensitivity of inhalation studies.

At the same time that carcinogenicity of very thin glass fibers after intrapleural and intraperitoneal (ip) administration was demonstrated (1,2) researchers found that gypsum fibers and HCI-leached chrysotile fibers were easily soluble in the peritoneal cavity. This led to the conclusion that the chemical composition of fibers was not responsible for the carcinogenesis but that the degree of carcinogenic potency of a fiber depended on the extent to which it retained its fibrous structure. A thin glass fiber with a low biodurability did not induce tumors after ip injection of a high dose, although the ip test had been criticized for being "overly sensitive." The ip model has been the most successful for determining carcinogenicity of inorganic fibers and establishing dose-response relationships; but to determine the possibilities and limitations of this test model, very high doses of nonfibrous silicon carbide and of a slightly durable glass fiber type were injected ip in Wistar rats. No obviously acute or chronic toxic effect was observed in 90 weeks, but there was a 40% incidence of serosal tumors in the group treated with glass fibers. A pilot study on the persistence of slag fibers in the omentum of rats after ip injection showed a half-time of about 1 year. It was calculated that an ip injection of 10(9) fibers would lead to a concentration of fiber numbers in the ash of the omentum in the same range as the concentration in the lung after 2 years of inhalation exposure. The long-term inhalation study with fibers in rats has been called the "gold standard" for risk characterization.(ABSTRACT TRUNCATED AT 250 WORDS

Empirical Evidences for Urban Influences on Public Health in Hamburg

Abstract: From the current perspectives of urban health and environmental justice research, health is the result of a combination of individual, social and environmental factors. Yet, there are only few attempts to determine their joint influence on health and well-being. Grounded in debates surrounding conceptual models and based on a data set compiled for the city of Hamburg, this paper aims to provide insights into the most important variables influencing urban health. Theoretically, we are primarily referring to the conceptual model of health-related urban well-being (UrbWellth), which systemizes urban influences in four sectors. The systematization of the conceptual model is empirically confirmed by a principal component analysis: the factors derived from the data correspond well with the deductively derived model. Additionally, a multiple linear regression analysis was used to identify the most important variables influencing the participant’s self-rated health (SRH): rating of one’s social network, rating of neighborhood air quality, rating of neighborhood health infrastructure, heat stress (day/outdoors), cold stress (night/indoors). When controlling for age, income and smoking behavior, these variables explain 12% of the variance of SRH. Thus, these results support the concept of UrbWellth empirically. Finally, the study design helped to identify hotspots with negative impact on SRH within the research areas

Dose-response relationship of fibrous dusts in intraperitoneal studies.

The relationship between the number of fibers injected intraperitoneally and the occurrence of peritoneal mesotheliomas in rats was investigated using data from a series of carcinogenicity studies with several fibrous dusts. Based on observed tumor incidences ranging between 10 and 90%, the hypothesis of a common slope of dose-response relationships (parallel probit lines in probit analysis) cannot be rejected. In general, parallelism of probit lines is considered an indication of a common mode of action. Analysis of the shape of the dose-response relationship, with one apparent exception, shows virtually linear or superlinear behavior, i.e., from these data, there is no indication of a decrease in carcinogenic potency of an elementary carcinogenic unit at lower doses

A EMBRAPA no Pantanal Mato-Grossense.

A Unidade de Execucao de Pesquisa de Ambito Estadual de Corumba, da Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA), tem como objetivos avaliar as potencialidades dos diferentes ecossistemas da regiao e estabelecer o suporte cientifico que devera nortear sua exploracao em bases economicas e ecologicas. Espera-se que, com a geracao e adaptacao de tecnologia, seja possivel, a curto e medio prazo, obter incrementos positivos nos indices de produtividade da pecuaria regional. Pesquisas em andamento estao mostrando esta tendencia, o que evidencia o potencial da regiao a novas tecnologias.bitstream/item/37788/1/DOC01.pd

Forrageamento e nutrição mineral de bovinos de corte no Pantanal.

Nutrição mineral de bovinos de corte no Pantanal; Concentração de minerais em pastagens cultivadas; Suplementação mineral em pastagens.bitstream/item/81200/1/DOC39.pd

Identificação preliminar de grupos funcionais em pastagens nativas no Pantanal.

As pastagens nativas do Pantanal são dinâmicas, principalmente devido às inundações periódicas. O conhecimento sobre os grupos funcionais dos estados de transição dessas comunidades é de extrema importância no manejo para resiliência do ecossistema. Este artigo objetivou identificar grupos funcionais de plantas em uma borda de baía, influenciada por inundação e superpastejo, de bovinos ao longo do tempo. O trabalho foi desenvolvido na borda de uma lagoa superpastejada na fazenda Nhumirim, sub-região da Nhecolândia, Pantanal, no período de setembro 2007 a março 2010

Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 $\mu$m). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feedforward approach to stabilize the path length fluctuations seen by the LBTI nuller.Comment: SPIE conference proceeding

Resposta de dois cultivares de aveia ao nitrogênio, em três freqüências de corte e duas épocas de plantio. II. Valor Nutritivo.

Este trabalho enfocou apenas a produção de forragem obtida na freqüência de dois cortes, em que foram avaliados efeitos de doses de nitrogênio (0, 40, 80, 160 e 320 kg ha ') e de duas épocas de plantio (abril e maio), no valor nutritivo da forragem de dois cultivares de aveia (São Carlos e UPF 3). 0 experimento foi conduzido em Latossolo Vermelho- Escuro, sob irrigação, na Embrapa Pecuária Sudeste, localizada em São Carlos, SP. Três blocos casualizados foram usados, com os tratamentos organizados em esquema fatorial (dois cortes X cinco doses de N). Na primeira época de plantio verificou-se que doses maiores de N acarretaram teores maiores de proteína bruta (PB) na forragem do segundo corte nos dois cultivares. No cultivar São Carlos, o teor de P no segundo corte decresceu com as doses de N. No cultivar UPF 3, o teor de Mg aumentou com as doses de N, no segundo corte. A forragem do primeiro corte nos dois cultivares apresentou teores de maiores de fibra em detergente neutro (FDN), e de Mg apenas no cultivar UPF 3; e a do segundo coite, valores maiores de PB, digestibilidade in vitro da matéria seca (DIVMS) P e Ca, exceto no cultivar UPF, 3, que nao apresentou diferença entre cortes nos teores de Ca. Na segunda época de plantio, verificou-se, no segundo corte, nos dois cultivares, que a dose maior de N gerou teores maiores de PB e que ocorreu decréscimo no teor de P com o aumento das doses de N, no cultivar São Carlos. No segundo corte ocorreram teoresmaiores de PB, CA, P. Mg, em ambos os cultivares, exceto no cultivar Sao Carlos, em que os teores de Mg foram iguais no dois cortes; e valores nemores de FDN e DIVMS, sendo a DIVMS semelhantes nos dois cortes no cultivar Sao Carlos