889 resultados para k-out-of-n system


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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

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The advent of next-generation sequencing has significantly reduced the cost of obtaining large-scale genetic resources, opening the door for genomic studies of non-model but ecologically interesting species. The shift in mating system, from outcrossing to selfing, has occurred thousands of times in angiosperms and is accompanied by profound changes in the population genetics and ecology of a species. A large body of work has been devoted to understanding why the shift occurs and the impact of the shift on the genetics of the resulting selfing populations, however, the causes and consequences of the transition to selfing involve a complicated interaction of genetic and demographic factors which are difficult to untangle. Abronia umbellata is a Pacific coastal dune endemic which displays a striking shift in mating system across its geographic range, with large-flowered outcrossing populations south of San Francisco and small-flowered selfing populations to the north. Abronia umbellata is an attractive model system for the study of mating system transitions because the shift appears to be recent and therefore less obscured by post-shift processes, it has a near one-dimensional geographic range which simplifies analysis and interpretation, and demographic data has been collected for many of the populations. In this study, we generated transcriptome-level data for 12 plants including individuals from both subspecies, along with a resequencing study of 48 individuals from populations across the range. The genetic analysis revealed a recent transition to selfing involving a drastic reduction in genetic diversity in the selfing lineage, potentially indicative of a recent population bottleneck and a transition to selfing due to reproductive assurance. Interestingly, the genetic structure of the populations was not coincident with the current subspecies demarcation, and two large-flowered populations were classified with the selfing subspecies, suggesting a potential need for re-evaluation of the current subspecies classification. Our finding of low diversity in selfing populations may also have implications for the conservation value of the threatened selfing subspecies.

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Major food adulteration and contamination events occur with alarming regularity and are known to be episodic, with the question being not if but when another large-scale food safety/integrity incident will occur. Indeed, the challenges of maintaining food security are now internationally recognised. The ever increasing scale and complexity of food supply networks can lead to them becoming significantly more vulnerable to fraud and contamination, and potentially dysfunctional. This can make the task of deciding which analytical methods are more suitable to collect and analyse (bio)chemical data within complex food supply chains, at targeted points of vulnerability, that much more challenging. It is evident that those working within and associated with the food industry are seeking rapid, user-friendly methods to detect food fraud and contamination, and rapid/high-throughput screening methods for the analysis of food in general. In addition to being robust and reproducible, these methods should be portable and ideally handheld and/or remote sensor devices, that can be taken to or be positioned on/at-line at points of vulnerability along complex food supply networks and require a minimum amount of background training to acquire information rich data rapidly (ergo point-and-shoot). Here we briefly discuss a range of spectrometry and spectroscopy based approaches, many of which are commercially available, as well as other methods currently under development. We discuss a future perspective of how this range of detection methods in the growing sensor portfolio, along with developments in computational and information sciences such as predictive computing and the Internet of Things, will together form systems- and technology-based approaches that significantly reduce the areas of vulnerability to food crime within food supply chains. As food fraud is a problem of systems and therefore requires systems level solutions and thinking.

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The possibility of the EU member states to adapt copyright legislation to new circumstances and to address unforeseen issues is limited by the list of exceptions and restrictions of the InfoSoc Directive. In spite of this constraint, the EU copyright framework provides for a possibility of introduction of non-voluntary forms of collective rights management that can help to tackle some of the contemporary problems with remuneration and access. This article is an attempt to deepen the understanding of non-voluntary collective management and its possible use. First, it provides a detailed description of the French mechanism adopted for facilitating mass digitization and making out-of-commerce books available, which was implemented through a new form of collective management of copyright. Then, it examines the mechanism’s compatibility with the InfoSoc Directive through comparison with the extended collective licensing.

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Thesis (Master's)--University of Washington, 2016-06

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Abstract Background: Paediatric oncology palliative care in the community is rare and nationally there is a lack of standardisation of out of hours nursing service provision. Objectives: This paper seeks to explore influences on the experiences of paediatric nurses providing out of hours palliative care within the family home to children with cancer. The study used social worlds theory to aid identification and demonstration of the findings. Methods: Twelve community-based palliative cases were purposively selected from children with cancer treated at one regional centre. Tape-recorded interviews were undertaken with 54 health professionals (general practitioners, community nurses and allied health professionals) involved in providing their palliative care and five facilitated case discussions completed. Data analysis followed a grounded theory approach; chronological comparative data analysis identifying generated themes. Social worlds theory was used as a framework to examine the data. Results: Nurses’ experiences are shaped by their social world and those of the nursing team,child and family and the inter-professional team providing the care. The lack of a formalised service, sub-optimal inter-professional working and impact of social worlds influence the experience of the nurse. Conclusions: Social worlds theory provided a new perspective in understanding these experiences based within a paediatric palliative care setting, knowledge that can be used to inform service provision.

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Thesis (Ph.D.)--University of Washington, 2016-08

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This purely theoretical thesis covers aspects of two contemporary research fields: the non-equilibrium dynamics in quantum systems and the electronic properties of three-dimensional topological insulators. In the first part we investigate the non-equilibrium dynamics in closed quantum systems. Thanks to recent technologies, especially from the field of ultracold quantum gases, it is possible to realize such systems in the laboratory. The focus is on the influence of hydrodynamic slow modes on the thermalization process. Generic systems in equilibrium, either classical or quantum, in equilibrium are described by thermodynamics. This is characterized by an ensemble of maximal entropy, but constrained by macroscopically conserved quantities. We will show that these conservation laws slow down thermalization and the final equilibrium state can be approached only algebraically in time. When the conservation laws are violated thermalization takes place exponential in time. In a different study we calculate probability distributions of projective quantum measurements. Newly developed quantum microscopes provide the opportunity to realize new measurement protocols which go far beyond the conventional measurements of correlation functions. The second part of this thesis is dedicated to a new class of materials known as three-dimensional topological insulators. Also here new experimental techniques have made it possible to fabricate these materials to a high enough quality that their topological nature is revealed. However, their transport properties are not fully understood yet. Motivated by unusual experimental results in the optical conductivity we have investigated the formation and thermal destruction of spatially localized electron- and hole-doped regions. These are caused by charged impurities which are introduced into the material in order to make the bulk insulating. Our theoretical results are in agreement with the experiment and can explain the results semi-quantitatively. Furthermore, we study emergent lengthscales in the bulk as well as close to the conducting surface.

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Seaports play a critical role as gateways and facilitators of economic interchange and logistics processes and thus have become crucial nodes in globalised production networks andmobility systems. Both the physical port infrastructure and its operational superstructure have undergone intensive evolution processes in an effort to adapt to changing economic environments, technological advances,maritime industry expectations and institutional reforms. The results, in terms of infrastructure, operator models and the role of an individual port within the port system, vary by region, institutional and economic context. While ports have undoubtedly developed in scale to respond to the changing volumes and structures in geographies of trade (Wilmsmeier, 2015), the development of hinterland access infrastructure, regulatory systems and institutional structures have in many instances lagged behind. The resulting bottlenecks reflect deficits in the interplay between the economic system and the factors defining port development (e.g. transport demand, the structure of trade, transport services, institutional capacities, etc. cf. Cullinane and Wilmsmeier, 2011). There is a wide range of case study approaches and analyses of individual ports, but analyses from a port system perspective are less common, and those that exist are seldom critical of the dominant discourse assuming the efficiency of market competition (cf. Debrie et al., 2013). This special section aims to capture the spectrum of approaches in current geography research on port system evolution. Thus, the papers reach from the traditional spatial approach (Rodrigue and Ashar, this volume) to network analysis (Mohamed-Chérif and Ducruet, this volume) to institutional discussions (Vonck and Notteboom, this volume; Wilmsmeier and Monios, this volume). The selection of papers allows an opening of discussion and reflection on current research, necessary critical analysis of the influences on port systemevolution and,most importantly, future directions. The remainder of this editorial aims to reflect on these challenges and identify the potential for future research.

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“Falling Out of the Sky” is a collection of poems, both formal and free verse, that explores an intimate familial landscape. In particular, these poems raise the question of what it means to be human through examinations of family mythology and its changes as bodies and memories become unreliable with time.

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La pobreza es un problema mundial que afecta a personas de diferentes maneras. El propósito de este artículo es explorar dos teorías principales que abordan la pobreza y la posibilidad de su superación, que son los enfoques de capital humano y de capacidades humanas. El enfoque del capital humano se centra exclusivamente en la faceta económica de la pobreza; en esta perspectiva, la pobreza se define como la falta de dinero y puede abordarse mediante el aumento de los ingresos financieros de las personas que viven en la pobreza. El enfoque de las capacidades humanas ve la pobreza como un problema multidimensional que va más allá de la economía para áreas como la salud, la educación y la libertad. Este enfoque se orienta hacia el cambio social y ayudar a las personas en situación de pobreza para descubrir y desarrollar su potencial. El autor considera que las capacidades humanas abarcan con mayor precisión el alcance de la pobreza y las personas afectadas por el mismo, aunque debido a su amplia gama ha sido difícil diseñar e implementar políticas eficaces que aborden todas las facetas de la pobreza.

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This article contests Sean McMeekin’s claims concerning Russian culpability for the First World War. McMeekin maintains that Ottoman rearmament, particularly the purchase of several battleships released onto the global arms market by South American states, threatened to create a situation where the Russian Black Sea Fleet would be outclassed by its Ottoman opposite number. Rather than waiting for this to happen, the tsarist regime chose to go to war. Yet, contrary to McMeekin’s claims, the Ottoman naval expansion never assumed threatening dimensions because the Porte was unable to purchase battleships from Chile or Argentina. As a result, it provided no incentive for Russia to go to war in 1914.