146 research outputs found
Graph Minors and Parameterized Algorithm Design
Abstract. The Graph Minors Theory, developed by Robertson and Sey-mour, has been one of the most influential mathematical theories in pa-rameterized algorithm design. We present some of the basic algorithmic techniques and methods that emerged from this theory. We discuss its direct meta-algorithmic consequences, we present the algorithmic appli-cations of core theorems such as the grid-exclusion theorem, and we give a brief description of the irrelevant vertex technique
Dimensão econômica de sistemas de integração lavoura-pecuária
Os sistemas de integração lavoura-pecuária (ILP) têm sido propostos como solução tecnológica para atender critérios de sustentabilidade, mas tal assertiva tem-se baseado principalmente em indicadores agronômicos e ambientais. Neste trabalho, explorou-se a perspectiva econômica da ILP. Os benefícios econômicos potenciais desses sistemas podem refletir-se em economia de escopo (diminuição do custo, em razão da produção de múltiplos produtos) ou nos efeitos de redução de risco pela diversificação. Além disso, eles podem envolver menor variabilidade produtiva e maior produtividade. A mensuração acurada das interações entre os componentes lavoura e animal (pastagem) é etapa-chave a ser perseguida. A tomada de decisão em prol de sistemas diversificados vis-à-vis sistemas especializados deve ser feita de acordo com os preços relativos. A ILP compete com sistemas especializados de pecuária, mas não apresenta taxas de retorno competitivas em comparação a sistemas especializados com soja. A elevada demanda por capital da ILP, particularmente para a aquisição de animais em recria para a engorda, explica as menores taxas de retorno da ILP e é vista como uma das principais restrições para a ampla adoção de sistemas mistos. O desenho de mecanismos de financiamento inovadores será essencial para promover e acelerar a adoção em larga escala da tecnologia
A2ML1 and otitis media: novel variants, differential expression, and relevant pathways
A genetic basis for otitis media is established, however, the role of rare variants in disease etiology is largely unknown. Previously a duplication variant within A2ML1 was identified as a significant risk factor for otitis media in an indigenous Filipino population and in US children. In this report exome and Sanger sequencing was performed using DNA samples from the indigenous Filipino population, Filipino cochlear implantees, US probands, Finnish, and Pakistani families with otitis media. Sixteen novel, damaging A2ML1 variants identified in otitis media patients were rare or low-frequency in population-matched controls. In the indigenous population, both gingivitis and A2ML1 variants including the known duplication variant and the novel splice variant c.4061 + 1 G>C were independently associated with otitis media. Sequencing of salivary RNA samples from indigenous Filipinos demonstrated lower A2ML1 expression according to the carriage of A2ML1 variants. Sequencing of additional salivary RNA samples from US patients with otitis media revealed differentially expressed genes that are highly correlated with A2ML1 expression levels. In particular, RND3 is upregulated in both A2ML1 variant carriers and high-A2ML1 expressors. These findings support a role for A2ML1 in keratinocyte differentiation within the middle ear as part of otitis media pathology and the potential application of ROCK inhibition in otitis media
Alcohol, tobacco and breast cancer – collaborative reanalysis of individual data from 53 epidemiological studies, including 58 515 women with breast cancer and 95 067 women without the disease
Alcohol and tobacco consumption are closely correlated and published results on their association with breast cancer have not always allowed adequately for confounding between these exposures. Over 80% of the relevant information worldwide on alcohol and tobacco consumption and breast cancer were collated, checked and analysed centrally. Analyses included 58 515 women with invasive breast cancer and 95 067 controls from 53 studies. Relative risks of breast cancer were estimated, after stratifying by study, age, parity and, where appropriate, women's age when their first child was born and consumption of alcohol and tobacco. The average consumption of alcohol reported by controls from developed countries was 6.0 g per day, i.e. about half a unit/drink of alcohol per day, and was greater in ever-smokers than never-smokers, (8.4 g per day and 5.0 g per day, respectively). Compared with women who reported drinking no alcohol, the relative risk of breast cancer was 1.32 (1.19–1.45, P<0.00001) for an intake of 35–44 g per day alcohol, and 1.46 (1.33–1.61, P<0.00001) for ⩾45 g per day alcohol. The relative risk of breast cancer increased by 7.1% (95% CI 5.5–8.7%; P<0.00001) for each additional 10 g per day intake of alcohol, i.e. for each extra unit or drink of alcohol consumed on a daily basis. This increase was the same in ever-smokers and never-smokers (7.1% per 10 g per day, P<0.00001, in each group). By contrast, the relationship between smoking and breast cancer was substantially confounded by the effect of alcohol. When analyses were restricted to 22 255 women with breast cancer and 40 832 controls who reported drinking no alcohol, smoking was not associated with breast cancer (compared to never-smokers, relative risk for ever-smokers=1.03, 95% CI 0.98–1.07, and for current smokers=0.99, 0.92–1.05). The results for alcohol and for tobacco did not vary substantially across studies, study designs, or according to 15 personal characteristics of the women; nor were the findings materially confounded by any of these factors. If the observed relationship for alcohol is causal, these results suggest that about 4% of the breast cancers in developed countries are attributable to alcohol. In developing countries, where alcohol consumption among controls averaged only 0.4 g per day, alcohol would have a negligible effect on the incidence of breast cancer. In conclusion, smoking has little or no independent effect on the risk of developing breast cancer; the effect of alcohol on breast cancer needs to be interpreted in the context of its beneficial effects, in moderation, on cardiovascular disease and its harmful effects on cirrhosis and cancers of the mouth, larynx, oesophagus and liver
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