92 research outputs found

    Can forest management based on natural disturbances maintain ecological resilience?

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    Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

    ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a

    Meta-analysis of type 2 Diabetes in African Americans Consortium

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    Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

    Níveis de Proteína Bruta da Ração para Marrãs em Gestação Levels of Crude Protein of the Ration for Gilts in Gestation

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    Foram utilizadas 50 marrãs mestiças (Landrace, Large White e Pietrain) com média de peso de 136,34 ±16,05 kg e idade média de 220 dias, respectivamente, para avaliar diferentes níveis de proteína bruta da ração desses animais. Foi empregado o delineamento de blocos ao acaso, com cinco tratamento, 10 repetições e um animal por unidade experimental. Os tratamentos corresponderam a rações com 10,0; 11,5; 13,0; 14,5; e 16,0% de proteína bruta. O ganho de peso das marrãs até os 90 dias de gestação e o peso dos leitões e da leitegada se elevaram de forma linear com o aumento do nível de proteína da ração. Houve efeito quadrático dos níveis de proteína sobre o consumo da porca na lactação, que aumentou até o nível de 12,96% de PB. Não se verificou efeito dos tratamentos sobre o número de leitões nascidos, o número de dias desmame-cio e sobre o ganho de peso da porca durante todo o ciclo reprodutivo. Entretanto, houve efeito quadrático sobre o número de leitões desmamados, que aumentou até o nível de 13,33% de PB. Os níveis de proteína bruta que propiciaram menor taxa de mortalidade dos leitões na fase de lactação situaram-se entre 11,5 e 16% de PB. O melhor nível de proteína bruta nas dietas no período de gestação para marrãs pesando 136,34 ±16,05 kg e idade média de 220 dias foi de 13,31%, correspondendo a um consumo estimado de 240 g de proteína/dia ou 0,67% de lisina (12,06 g/dia), respectivamente.<br>Fifty crossbreed gilts (Landrace, Large White and Pietrain) with 136.34±16.05 and 220 days of average weight and age, respectively, were used to evaluate diets with different crude protein levels, at the gestation period. A complete randomized blocks design, with five treatments, ten replicates and one animal per experimental unit, was used. The treatments corresponded to the diets with 10.0, 11.5, 13.0, 14.5 and 16.0% of crude protein. The weight gains of the gilts at the 90 days of the gestation period and the individual and total weight of the pigs and litter linearly increased in function of the crescent crude protein level in the diets. There was quadratic effect of the crude protein levels in the diets on the gilts dry matter consumption in the subsequent lactation period. This may be a consequence response of the crude protein level in the diets fed to the gilts at the gestation period. The highest calculated dry matter consumption was at 12.96% of crude protein. No effect of the treatments on the number of weaned pigs was observed, but it increased up to the level of 13.33% of crude protein. A linear decreasing effect was observed on the relative weight of the gilts at the weaning time of the pigs also in function of the crescent crude protein levels in the diets at the gestation period. The best crude protein level in the diets at the gestation period for gilts weighting 136,34±16.05 and with 220 days of age was 13.31% crude protein, corresponding to a dry matter consumption of 240 g of protein/day or 0.67% of lysine (12.06 g/day)
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