276 research outputs found

    Meiofauna as descriptor of tourism-induced changes at sandy beaches

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    Tourism has long been considered as a ‘clean industry’ with almost no negative effects on the environment. This study demonstrated, in two different coastal systems (Mediterranean and Baltic), that tourism related activities are particularly affecting the sandy beach meio- and nematofauna in the upper beach zone, the specific ecotone in which many meiofauna species from both the marine and the terrestrial environment congregate. Tourist upper beaches are characterized by a lower % total organic matter (%TOM), lower densities, lower diversities (absence of Insecta, Harpacticoida, Oligochaeta, terrestrial nematodes and marine Ironidae nematodes) and higher community stress compared to nearby non-tourist locations. The %TOM was found to be the single most important factor for the observed differences in meiofauna assemblage structure at tourist versus non-tourist beaches in both the Mediterranean and the Baltic region. The free-living nematode assemblages from tourist upper zones depart significantly from expectations based on random selections from the regional nematode species pool. Furthermore upper zone assemblages are characterised by a low species diversity consisting of taxonomically closely related nematode species with r-strategist features. Generally, faunal differences between tourist and non-tourist beaches are decreasing towards the lower beach zones

    Variation of genetic and behavioural traits in the sandhopper Talitrus saltator (Crustacea Amphipoda) along a dynamic sand beach

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    In an attempt to unravel the possible relationships among coastal stability, genetic variability and orientation behaviour in the sandhopper Talitrus saltator, we have screened four subpopulations of this species. Sandhoppers along 3 km of a dynamic sand beach were studied for orientation performance (i.e. adherence to the seaward theoretical escape direction (TED)) and sequence variation for a fragment of the mitochondrial (mt) gene encoding for the cytochrome oxidase Subunit I (COI). The sampling sites differed in the stability of the shoreline (from severely eroded to accreting). Analysis of molecular variance (AMOVA) revealed significant subdivisions among the four locations. The subpopulation sampled at the most eroded point showed no haplotype diversity and had the highest scatter in orientation. Genetic diversity increased with decreasing erosion. Orientation performances were best where the beach is in dynamic equilibrium, and were progressively more scattered at the accreting points. Multiple linear regression analyses demonstrated that the variables and factors that affected orientation significantly were daytime, global solar radiation, sex of individuals and haplotype diversity. Environmental factors are likely to influence sandhopper behaviour on a short and medium time scale (i.e. from single individual life span to a few generations). The data also suggest that temporal stability of the shoreline has a positive effect on the genetic variability of the resident sandhopper populations

    Energia metabolizável da glicerina bruta e de dietas contendo glicerina bruta para frangos de corte na fase inicial.

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    Com a variação nos preços dos alimentos a glicerina bruta (GB) pode se tornar uma realidade na substituição parcial ao milho, tornando-se importante a determinação da energia metabolizável aparente (EMAn) deste alimento. Assim sendo, objetivou-se determinar a EMAn da GB e de rações formuladas com níveis crescentes de GB para frangos de corte na fase inicial (7 a 21 dias). Para a avaliação da EMAn das rações foi realizada coleta total de excretas dos 10 aos 18 dias de idade, sendo que os primeiros 4 dias foram de adaptação e os últimos 5 de coleta. Foi utilizado o delineamento experimental inteiramente casualizado com 4 tratamentos (0, 4, 8 e 12% de inclusão de GB nas rações) e 9 repetições de 10 aves por tratamento. Para a avaliação da EMAn da GB foi adicionado um tratamento com a inclusão de 8% de GB na ração referência (0% de GB) e utilizado nove repetições de 10 aves por gaiola. Não houve diferença significativa na EMAn entre os níveis de inclusão de 4 e 8% quando comparados ao controle (0%). Houve efeito linear decrescente para EMAn das dietas avaliadas com a inclusão de GB. A EMAn da GB determinada no ensaio foi de 2651 kcal/kg. Observou-se redução na matéria seca (MS) das excretas e aumento na produção de excretas na MS com o aumento dos níveis de inclusão, fato que pode explicar a reduzida EMAn da GB em inclusões acima de 4%. É necessária a correção do valor de EMAn da GB nas dietas em função do nível de inclusão

    CXCR2 deficient mice display macrophage-dependent exaggerated acute inflammatory responses

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    CXCR2 is an essential regulator of neutrophil recruitment to inflamed and damaged sites and plays prominent roles in inflammatory pathologies and cancer. It has therefore been highlighted as an important therapeutic target. However the success of the therapeutic targeting of CXCR2 is threatened by our relative lack of knowledge of its precise in vivo mode of action. Here we demonstrate that CXCR2-deficient mice display a counterintuitive transient exaggerated inflammatory response to cutaneous and peritoneal inflammatory stimuli. In both situations, this is associated with reduced expression of cytokines associated with the resolution of the inflammatory response and an increase in macrophage accumulation at inflamed sites. Analysis using neutrophil depletion strategies indicates that this is a consequence of impaired recruitment of a non-neutrophilic CXCR2 positive leukocyte population. We suggest that these cells may be myeloid derived suppressor cells. Our data therefore reveal novel and previously unanticipated roles for CXCR2 in the orchestration of the inflammatory response
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