165 resultados para Complementarity Determining Regions
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We present a novel approach to network security against passive eavesdroppers by employing a configurable beam-forming technique to create tightly defined regions of coverage for targeted users. In contrast to conventional encryption methods, our security scheme is developed at the physical layer by configuring antenna array beam patterns to transmit the data to specific regions. It is shown that this technique can effectively reduce vulnerability of the physical regions to eavesdropping by adapting the antenna configuration according to the intended user's channel state information. In this paper we present the application of our concept to 802.11n networks where an antenna array is employed at the access point, and consider the issue of minimizing the coverage area of the region surrounding the targeted user. A metric termed the exposure region is formally defined and used to evaluate the level of security offered by this technique. A range of antenna array configurations are examined through analysis and simulation, and these are subsequently used to obtain the optimum array configuration for a user traversing a coverage area.
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The cultivation of genetically modified (GM) crops in the EU is highly harmonised, involving a central authorisation procedure that aims to ensure a high level of environmental and human health protection. However conflicts over authority persist and the Commission has responded to a combination of internal and external pressures with a more flexible approach to coexistence, a proposed opt-out clause and recently a promise by the head of the Commission to review the existing EU GM legislative regime, providing an opportunity to consider and suggest paths of development. In light of the significance of multilevel governance and subsidiarity for GM cultivation, this paper considers the policy-making powers of the Member States and subnational regions in this regime, focussing upon post-authorisation options in particular. A number of core mechanisms exist, including voluntary measures, safeguard clauses, coexistence measures, a proposed express opt-out and Article 4(2) TEU on ‘national identity. These mechanisms are examined in light of the goals and challenges of multilevel governance, in order to consider whether the relevant powers are located at the appropriate level. Overall, it is apparent that the developments occurring at the EU level are strengthening multilevel governance, but with significant opportunities to improve it further through focussing on the supporting roles and the regional levels in particular.
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During the benthic cultivation process of Mytilus edulis (blue mussels), wild mussel seed is often transplanted from naturally occurring subtidal beds to sheltered in-shore waters to be grown to a commercial size. The survival of these relaid mussels is ultimately a function of their quality and physiological condition upon relaying and it has been recognised that mussels can suffer from a loss in condition following transportation. We investigated whether the process of being transported to ongrowing plots had a negative effect on the physiological health and resultant behaviour of mussels by simulating transportation conditions in a controlled experiment. Mussels were kept, out of water, in plastic piping to recreate translocation conditions and further, we tested if depth held in a ship hold (0, 1.5 and 3 m) and length of time emersed (12, 24 and 48 h) affected mussel condition and behaviour. Physiological condition was assessed by quantifying mussel tissue pH and whole tissue glucose, glycogen, succinate and propionate concentrations. The rate of byssogenesis was also quantified to estimate recovery following a period of re-immersion. The depth at which mussels were held did not affect any of the physiological indicators of mussel stress but short-term byssus production was affected. Mussels held at 3 m produced fewer byssus threads during the first 72 h following re-immersion compared with mussels at 0 m (i.e. not buried) suggesting that depth held can impede recovery following transportation. Duration of emersion affected all stress indicators. Specifically, mussels held out of water for 48 h had a reduced physiological condition compared with those emersed for just 12 h. This work has practical implications for the benthic cultivation industry and based on these results we recommend that mussels are held out of water for less than 24 h prior to relaying to ensure physiological health and resultant condition is preserved.
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This paper reports variations of polycyclic aromatic hydrocarbons (PAHs) features that were found in Spitzer Space Telescope spectra of carbon-rich post-asymptotic giant branch (post-AGB) stars in the Large Magellanic Cloud (LMC). The paper consists of two parts. The first part describes our Spitzer spectral observing programme of 24 stars including post-AGB candidates. The latter half of this paper presents the analysis of PAH features in 20 carbon-rich post-AGB stars in the LMC, assembled from the Spitzer archive as well as from our own programme.We found that five post-AGB stars showed a broad feature with a peak at 7.7 μm, that had not been classified before. Further, the 10-13 μm PAH spectra were classified into four classes, one of which has three broad peaks at 11.3, 12.3 and 13.3 μm rather than two distinct sharp peaks at 11.3 and 12.7 μm, as commonly found in HII regions. Our studies suggest that PAHs are gradually processed while the central stars evolve from post-AGB phase to planetary nebulae, changing their composition before PAHs are incorporated into the interstellar medium. Although some metallicity dependence of PAH spectra exists, the evolutionary state of an object is more significant than its metallicity in determining the spectral characteristics of PAHs for LMC and Galactic post-AGB stars. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
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A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth—including the potential for terrestrial microbial life to survive and replicate under martian environmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as “Uncertain” or “Special” as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation of where Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity. Key Words: Martian environments—Mars astrobiology—Extreme environment microbiology—Planetary protection—Exploration resources. Astrobiology 14, 887–968.
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Essay Review of Katarzyna Stokłosa and Gerhard Besier (eds) (2014) European Border Regions in Comparison: Overcoming Nationalistic Aspects or Re-Nationalization? (London: Routledge)
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Story understanding involves many perceptual and cognitive subprocesses, from perceiving individual words, to parsing sentences, to understanding the relationships among the story characters. We present an integrated computational model of reading that incorporates these and additional subprocesses, simultaneously discovering their fMRI signatures. Our model predicts the fMRI activity associated with reading arbitrary text passages, well enough to distinguish which of two story segments is being read with 74% accuracy. This approach is the first to simultaneously track diverse reading subprocesses during complex story processing and predict the detailed neural representation of diverse story features, ranging from visual word properties to the mention of different story characters and different actions they perform. We construct brain representation maps that replicate many results from a wide range of classical studies that focus each on one aspect of language processing and offer new insights on which type of information is processed by different areas involved in language processing. Additionally, this approach is promising for studying individual differences: it can be used to create single subject maps that may potentially be used to measure reading comprehension and diagnose reading disorders.
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This article reveals the effect of plasma pre-treatment on antimony tin oxide (ATO) nanoparticles. The effect is to allow Pt@Pd to be deposited homogeneously on the ATO surface with high dispersion and narrow particle size distribution. The Pt@Pd core–shell catalyst was prepared using the polyol method and shows a dramatic improvement towards ORR activity and durability.
Resumo:
Technological learning refers to the learning processes involved in improving the productive capabilities of an enterprise, sector or economy to enable it to produce higher quality goods or services with increasing levels of efficiency. Approaches to the study of technological learning include case studies of particular countries, sectors and firms; measures of export sophistication; and composite indicators of innovation and competitiveness. The present review draws on these approaches to provide an overview of the policies and practices that have been successful in different regions (East-Asia and Latin America) ; contexts (import substitution and liberalization) ; sectors (pulp and paper, IT services, electronics and passenger cars); and firms (Embrear and Lenovo). While it is clear that there is strong complementarity between domestic technological capability and the ability to absorb foreign technology, there is no simple policy recipe which is appropriate for all times, industries or places. Technological learning builds on and is shaped by what is already known. It requires time, space and resources all of which are influenced by the wider domestic and international context. The current international context is challenging but countries and firms have to find ways of moving forward despite the limited strategy space.
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The notion of privacy represents a central criterion for both indoor and outdoor social spaces in most traditional Arab settlements. This paper investigates privacy and everyday life as determinants of the physical properties of the built and urban fabric and will study their impact on traditional settlements and architecture of the home in the contemporary Iraqi city. It illustrates the relationship between socio-cultural aspects of public/private realms using the notion of the social sphere as an investigative tool of the concept of social space in Iraqi houses and local communities (Mahalla). This paper reports that in spite of the impact of other factors in articulating built forms, privacy embodies the primary role under the effects of Islamic rules, principles and culture. The crucial problem is the underestimation of traditional inherited values through opening social spaces to the outside that giving unlimited accesses to the indoor social environment creating many problems with regard to privacy and communal social integration.