391 research outputs found

    Comparative genomics of bdelloid rotifers: Insights from desiccating and nondesiccating species.

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    Bdelloid rotifers are a class of microscopic invertebrates that have existed for millions of years apparently without sex or meiosis. They inhabit a variety of temporary and permanent freshwater habitats globally, and many species are remarkably tolerant of desiccation. Bdelloids offer an opportunity to better understand the evolution of sex and recombination, but previous work has emphasised desiccation as the cause of several unusual genomic features in this group. Here, we present high-quality whole-genome sequences of 3 bdelloid species: Rotaria macrura and R. magnacalcarata, which are both desiccation intolerant, and Adineta ricciae, which is desiccation tolerant. In combination with the published assembly of A. vaga, which is also desiccation tolerant, we apply a comparative genomics approach to evaluate the potential effects of desiccation tolerance and asexuality on genome evolution in bdelloids. We find that ancestral tetraploidy is conserved among all 4 bdelloid species, but homologous divergence in obligately aquatic Rotaria genomes is unexpectedly low. This finding is contrary to current models regarding the role of desiccation in shaping bdelloid genomes. In addition, we find that homologous regions in A. ricciae are largely collinear and do not form palindromic repeats as observed in the published A. vaga assembly. Consequently, several features interpreted as genomic evidence for long-term ameiotic evolution are not general to all bdelloid species, even within the same genus. Finally, we substantiate previous findings of high levels of horizontally transferred nonmetazoan genes in both desiccating and nondesiccating bdelloid species and show that this unusual feature is not shared by other animal phyla, even those with desiccation-tolerant representatives. These comparisons call into question the proposed role of desiccation in mediating horizontal genetic transfer

    Film support and the challenge of ‘sustainability’: on wing design, wax and feathers, and bolts from the blue

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    In recognition of the importance of film in generating both economic and cultural value, the UK Labour government set up a new agency – the United Kingdom Film Council (UKFC) – in 2000 with a remit to build a sustainable film industry. But, reflecting a plethora of differing expectations in relation to the purposes behind public support for film, the UKFC's agenda shifted and broadened over the organisation's lifetime (2000–11). Apparently unconvinced by the UKFC's achievements, the Coalition government which came to power in May 2010 announced the Council's abolition and reassigned its responsibilities as part of a general cost-cutting strategy. Based on original empirical research, this article examines how the UKFC's sense of strategic direction was determined, how and why the balance of objectives it pursued changed over time and what these shifts tell us about the nature of film policy and the challenges facing bodies that are charged with enacting it in the twenty-first century

    Natural Compatibilism, Indeterminism, and Intrusive Metaphysics

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    The claim that common sense regards free will and moral responsibility as compatible with determinism has played a central role in both analytic and experimental philosophy. In this paper, we show that evidence in favor of this “natural compatibilism” is undermined by the role that indeterministic metaphysical views play in how people construe deterministic scenarios. To demonstrate this, we re-examine two classic studies that have been used to support natural compatibilism. We find that although people give apparently compatibilist responses, this is largely explained by the fact that people import an indeterministic metaphysics into deterministic scenarios when making judgments about freedom and responsibility. We conclude that judgments based on these scenarios are not reliable evidence for natural compatibilism

    Framing the Real: Lefèbvre and NeoRealist Cinematic Space as Practice

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    In 1945 Roberto Rossellini's Neo-realist Rome, Open City set in motion an approach to cinema and its representation of real life – and by extension real spaces – that was to have international significance in film theory and practice. However, the re-use of the real spaces of the city, and elsewhere, as film sets in Neo-realist film offered (and offers) more than an influential aesthetic and set of cinematic theories. Through Neo-realism, it can be argued that we gain access to a cinematic relational and multidimensional space that is not made from built sets, but by filming the built environment. On the one hand, this space allows us to "notice" the contradictions around us in our cities and, by extension, the societies that have produced those cities, while on the other, allows us to see the spatial practices operative in the production and maintenance of those contradictions. In setting out a template for understanding the spatial practices of Neo-realism through the work of Henri Lefèbvre, this paper opens its films, and those produced today in its wake, to a spatio-political reading of contemporary relevance. We will suggest that the rupturing of divisions between real spaces and the spaces of film locations, as well the blurring of the difference between real life and performed actions for the camera that underlies much of the central importance of Neo-realism, echoes the arguments of Lefèbvre with regard the social production of space. In doing so, we will suggest that film potentially had, and still has, a vital role to play in a critique of contemporary capitalist spatial practices

    Search for the standard model Higgs boson at LEP

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    Quantitative Interpretation of a Genetic Model of Carcinogenesis Using Computer Simulations

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    The genetic model of tumorigenesis by Vogelstein et al. (V theory) and the molecular definition of cancer hallmarks by Hanahan and Weinberg (W theory) represent two of the most comprehensive and systemic understandings of cancer. Here, we develop a mathematical model that quantitatively interprets these seminal cancer theories, starting from a set of equations describing the short life cycle of an individual cell in uterine epithelium during tissue regeneration. The process of malignant transformation of an individual cell is followed and the tissue (or tumor) is described as a composite of individual cells in order to quantitatively account for intra-tumor heterogeneity. Our model describes normal tissue regeneration, malignant transformation, cancer incidence including dormant/transient tumors, and tumor evolution. Further, a novel mechanism for the initiation of metastasis resulting from substantial cell death is proposed. Finally, model simulations suggest two different mechanisms of metastatic inefficiency for aggressive and less aggressive cancer cells. Our work suggests that cellular de-differentiation is one major oncogenic pathway, a hypothesis based on a numerical description of a cell's differentiation status that can effectively and mathematically interpret some major concepts in V/W theories such as progressive transformation of normal cells, tumor evolution, and cancer hallmarks. Our model is a mathematical interpretation of cancer phenotypes that complements the well developed V/W theories based upon description of causal biological and molecular events. It is possible that further developments incorporating patient- and tissue-specific variables may build an even more comprehensive model to explain clinical observations and provide some novel insights for understanding cancer

    Multiple Analytical Approaches Reveal Distinct Gene-Environment Interactions in Smokers and Non Smokers in Lung Cancer

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    Complex disease such as cancer results from interactions of multiple genetic and environmental factors. Studying these factors singularly cannot explain the underlying pathogenetic mechanism of the disease. Multi-analytical approach, including logistic regression (LR), classification and regression tree (CART) and multifactor dimensionality reduction (MDR), was applied in 188 lung cancer cases and 290 controls to explore high order interactions among xenobiotic metabolizing genes and environmental risk factors. Smoking was identified as the predominant risk factor by all three analytical approaches. Individually, CYP1A1*2A polymorphism was significantly associated with increased lung cancer risk (OR = 1.69;95%CI = 1.11–2.59,p = 0.01), whereas EPHX1 Tyr113His and SULT1A1 Arg213His conferred reduced risk (OR = 0.40;95%CI = 0.25–0.65,p<0.001 and OR = 0.51;95%CI = 0.33–0.78,p = 0.002 respectively). In smokers, EPHX1 Tyr113His and SULT1A1 Arg213His polymorphisms reduced the risk of lung cancer, whereas CYP1A1*2A, CYP1A1*2C and GSTP1 Ile105Val imparted increased risk in non-smokers only. While exploring non-linear interactions through CART analysis, smokers carrying the combination of EPHX1 113TC (Tyr/His), SULT1A1 213GG (Arg/Arg) or AA (His/His) and GSTM1 null genotypes showed the highest risk for lung cancer (OR = 3.73;95%CI = 1.33–10.55,p = 0.006), whereas combined effect of CYP1A1*2A 6235CC or TC, SULT1A1 213GG (Arg/Arg) and betel quid chewing showed maximum risk in non-smokers (OR = 2.93;95%CI = 1.15–7.51,p = 0.01). MDR analysis identified two distinct predictor models for the risk of lung cancer in smokers (tobacco chewing, EPHX1 Tyr113His, and SULT1A1 Arg213His) and non-smokers (CYP1A1*2A, GSTP1 Ile105Val and SULT1A1 Arg213His) with testing balance accuracy (TBA) of 0.6436 and 0.6677 respectively. Interaction entropy interpretations of MDR results showed non-additive interactions of tobacco chewing with SULT1A1 Arg213His and EPHX1 Tyr113His in smokers and SULT1A1 Arg213His with GSTP1 Ile105Val and CYP1A1*2C in nonsmokers. These results identified distinct gene-gene and gene environment interactions in smokers and non-smokers, which confirms the importance of multifactorial interaction in risk assessment of lung cancer
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