905 resultados para Advanced Encryption Standard


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Sea ice contains flaws including frictional contacts. We aim to describe quantitatively the mechanics of those contacts, providing local physics for geophysical models. With a focus on the internal friction of ice, we review standard micro-mechanical models of friction. The solid's deformation under normal load may be ductile or elastic. The shear failure of the contact may be by ductile flow, brittle fracture, or melting and hydrodynamic lubrication. Combinations of these give a total of six rheological models. When the material under study is ice, several of the rheological parameters in the standard models are not constant, but depend on the temperature of the bulk, on the normal stress under which samples are pressed together, or on the sliding velocity and acceleration. This has the effect of making the shear stress required for sliding dependent on sliding velocity, acceleration, and temperature. In some cases, it also perturbs the exponent in the normal-stress dependence of that shear stress away from the value that applies to most materials. We unify the models by a principle of maximum displacement for normal deformation, and of minimum stress for shear failure, reducing the controversy over the mechanism of internal friction in ice to the choice of values of four parameters in a single model. The four parameters represent, for a typical asperity contact, the sliding distance required to expel melt-water, the sliding distance required to break contact, the normal strain in the asperity, and the thickness of any ductile shear zone.

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Purpose – This paper extends the increasing debates about the role of international experience through mechanisms other than standard expatriation packages, in particular through the use of short-term assignments. It explores the different forms of short-term assignments (project work, commuter assignments, virtual international working and development assignments) and the different sets of positive and negative implications these can have for the company and the individuals concerned. The integration-differentiation debate is reflected here as elsewhere in IHRM, with the company moving towards greater centralization and control of its use of these assignments. Design/methodology/approach – Since the research is exploratory, we adopted a qualitative approach to get a more in-depth understanding on the realities the corporations and the assignees are facing. The study was implemented through a single case study setting in which the data were collected by interviewing (n=20) line managers, human resource management (HRM) staff and assignees themselves. In addition corporate documentation and other materials were reviewed. Findings – The present case study provides evidence about the characteristics of short-term assignments as well as the on the management of such assignments. The paper identifies various benefits and challenges involved in the use of short-term assignments both from the perspectives of the company and assignees. Furthermore, the findings support the view that a recent increase in the popularity of short-term assignments has not been matched by the development of HRM policies for such assignments. Research limitations/implications – As a single case study, limitations in the generalizability of the findings should be kept in mind. More large-scale research evidence is needed around different forms of international assignments beyond standard expatriation in order to fully capture the realities faced by international HRM specialists Practical implications – The paper identifies many challenges but also benefits of using short-term assignments. The paper reports in-depth findings on HR development needs that organizations face when expanding the use of such assignments. Social implications – The paper identifies many challenges but also benefits of using short-term assignments. The paper reports in-depth findings on HR development needs that organizations face when expanding the use of such assignments. Originality/value – Empirical research on short-term assignments is still very limited. In that way the paper provides much needed in-depth evidence on why such assignments are used, what challenges are involved in the use of such assignments and what kinds of HR-development needs are involved.

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Different theoretical accounts of second language (L2) acquisition differ with respect to whether or not advanced learners are predicted to show native like processing for features not instantiated in the native language (L1). We examined how native speakers of English, a language with number but not gender agreement, process number and gender agreement in Spanish. We compare agreement within a determiner phrase (órgano muy complejo “[DP organ-MASC-SG very complex-MASC-SG]”) and across a verb phrase (cuadro es auténtico “painting-MASC-SG [VP is authentic-MASC-SG]”) in order to investigate whether native like processing is limited to local domains (e.g. within the phrase), in line with Clahsen and Felser (2006). We also examine whether morphological differences in how the L1 and L2 realize a shared feature impact processing by comparing number agreement between nouns and adjectives, where only Spanish instantiates agreement, and between demonstratives and nouns, where English also instantiates agreement. Similar to Spanish natives, advanced learners showed a P600 for both number and gender violations overall, in line with the Full Transfer/Full Access Hypothesis (Schwartz and Sprouse, 1996), which predicts that learners can show native-like processing for novel features. Results also show that learners can establish syntactic dependencies outside of local domains, as suggested by the presence of a P600 for both within and across phrase violations. Moreover, similar to native speakers, learners were impacted by the structural distance (number of intervening phrases) between the agreeing elements, as suggested by the more positive waveforms for within than across-phrase agreement overall. These results are consistent with the proposal that learners are sensitive to hierarchical structure.

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In recent years both developed and developing countries have experienced an increasing number of government initiatives dedicated to reducing the administrative costs (AC) imposed on businesses by regulation. We use a bi-linear fixed-effects model to analyze the extent to which government initiatives to reduce AC through the Standard Cost Model (SCM) attract Foreign Direct Investment (FDI) among 32 developing countries. Controlling for standard determinants of the SCM, we find that the SCM in most cases leads to higher FDI and that the benefits are more significant where the SCM has been implemented for a longer period.

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Studies of code-switching in writing are very limited in comparison with the numerous investigations of this phenomenon in oral communication. Recent research has revealed that in text-based computer-mediated communication internet users bring into play the various languages available in their linguistic repertoire and, consequently, switch between them. In this case study, I investigate digital code-switching between Cypriot and Standard Greek, the two varieties of Greek spoken on the island of Cyprus. Following Auer’s conversation analytic approach and Gafaranga’s view that conversational structure coexists with social structure, I investigate code-switching in online interactions. The data to be analysed here, unlike those considered in most studies of code-switching, are written data, obtained from channel #Cyprus of Internet Relay Chat. The results suggest that code-switching in writing is influenced not only by macro-sociolinguistic factors, but they are also shaped by the medium- and social-specific characteristics of Internet Relay Chat. This, in turn, allows internet users to gain access to different roles and perform various identities within this online context.

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Cypriot Greek, a variety of Greek spoken in the island of Cyprus, is relatively distinct from Standard Greek in all linguistic domains. The regional variety does not have a standard, official orthography and it is rarely used for everyday written purposes. Following technological development and the emergence of Computer-mediated Communication, a Romanized version of written CG is now widely used in online text-based communication, among teenagers and young adults (Themistocleous, C. (2008), The use of Cypriot-Greek in synchronous computer-mediated communication (PhD thesis), University of Manchester). In this study, I present the innovative ways that Greek-Cypriots use Roman characters in an effort to represent features of their spoken language in their online writings. By analysing data obtained from channel #Cyprus of Internet Relay Chat, I demonstrate how the choice of writing in CG affects the ways that Roman characters are used. I argue that this practice is not just a response to technological constrains but it actually has a wider social significance.

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The encoding of goal-oriented motion events varies across different languages. Speakers of languages without grammatical aspect (e.g., Swedish) tend to mention motion endpoints when describing events, e.g., “two nuns walk to a house,”, and attach importance to event endpoints when matching scenes from memory. Speakers of aspect languages (e.g., English), on the other hand, are more prone to direct attention to the ongoingness of motion events, which is reflected both in their event descriptions, e.g., “two nuns are walking.”, and in their non-verbal similarity judgements. This study examines to what extent native speakers of Swedish (n = 82) with English as a foreign language (FL) restructure their categorisation of goal-oriented motion as a function of their English proficiency and experience with the English language (e.g., exposure, learning). Seventeen monolingual native English speakers from the United Kingdom (UK) were engaged for comparison purposes. Data on motion event cognition were collected through a memory-based triads matching task, in which a target scene with an intermediate degree of endpoint orientation was matched with two alternative scenes with low and high degrees of endpoint orientation, respectively. Results showed that the preference among the Swedish speakers of L2 English to base their similarity judgements on ongoingness rather than event endpoints was correlated with their use of English in their everyday lives, such that those who often watched television in English approximated the ongoingness preference of the English native speakers. These findings suggest that event cognition patterns may be restructured through the exposure to FL audio-visual media. The results thus add to the emerging picture that learning a new language entails learning new ways of observing and reasoning about reality.

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A set of high-resolution radar observations of convective storms has been collected to evaluate such storms in the UK Met Office Unified Model during the DYMECS project (Dynamical and Microphysical Evolution of Convective Storms). The 3-GHz Chilbolton Advanced Meteorological Radar was set up with a scan-scheduling algorithm to automatically track convective storms identified in real-time from the operational rainfall radar network. More than 1,000 storm observations gathered over fifteen days in 2011 and 2012 are used to evaluate the model under various synoptic conditions supporting convection. In terms of the detailed three-dimensional morphology, storms in the 1500-m grid-length simulations are shown to produce horizontal structures a factor 1.5–2 wider compared to radar observations. A set of nested model runs at grid lengths down to 100m show that the models converge in terms of storm width, but the storm structures in the simulations with the smallest grid lengths are too narrow and too intense compared to the radar observations. The modelled storms were surrounded by a region of drizzle without ice reflectivities above 0 dBZ aloft, which was related to the dominance of ice crystals and was improved by allowing only aggregates as an ice particle habit. Simulations with graupel outperformed the standard configuration for heavy-rain profiles, but the storm structures were a factor 2 too wide and the convective cores 2 km too deep.

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Recent studies showed that features extracted from brain MRIs can well discriminate Alzheimer’s disease from Mild Cognitive Impairment. This study provides an algorithm that sequentially applies advanced feature selection methods for findings the best subset of features in terms of binary classification accuracy. The classifiers that provided the highest accuracies, have been then used for solving a multi-class problem by the one-versus-one strategy. Although several approaches based on Regions of Interest (ROIs) extraction exist, the prediction power of features has not yet investigated by comparing filter and wrapper techniques. The findings of this work suggest that (i) the IntraCranial Volume (ICV) normalization can lead to overfitting and worst the accuracy prediction of test set and (ii) the combined use of a Random Forest-based filter with a Support Vector Machines-based wrapper, improves accuracy of binary classification.

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The paper seeks to draw attention to some of the recent cases relating to child custody law in Bangladesh where, deviating from orthodox Shari’a rules, courts have looked to ‘the welfare’ of the child in determining which parent shall have custody. In studying the recent ‘welfare of child’ standard that has been advanced by the courts in Bangladesh, the paper aims to explore its implications for Muslim women from a feminist perspective.

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Designing for indoor thermal environmental conditions is one of the key elements in the energy efficient building design process. This paper introduces a development of the Chinese national Evaluation Standard for indoor thermal environments (Evaluation Standard). International standards including the ASHRAE55, ISO7730, DIN EN, and CIBSE Guide-A have been reviewed and referenced for the development of the Evaluation Standard. In addition, over 28,000 subjects participated in the field study from different climate zones in China and over 500 subjects have been involved in laboratory studies. The research findings reveal that there is a need to update the Chinese thermal comfort standard based on local climates and people's habitats. This paper introduces in detail the requirements for the thermal environment for heated and cooled buildings and free-running buildings in China.

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Sea surface temperature (SST) datasets have been generated from satellite observations for the period 1991–2010, intended for use in climate science applications. Attributes of the datasets specifically relevant to climate applications are: first, independence from in situ observations; second, effort to ensure homogeneity and stability through the time-series; third, context-specific uncertainty estimates attached to each SST value; and, fourth, provision of estimates of both skin SST (the fundamental measure- ment, relevant to air-sea fluxes) and SST at standard depth and local time (partly model mediated, enabling comparison with his- torical in situ datasets). These attributes in part reflect requirements solicited from climate data users prior to and during the project. Datasets consisting of SSTs on satellite swaths are derived from the Along-Track Scanning Radiometers (ATSRs) and Advanced Very High Resolution Radiometers (AVHRRs). These are then used as sole SST inputs to a daily, spatially complete, analysis SST product, with a latitude-longitude resolution of 0.05°C and good discrimination of ocean surface thermal features. A product user guide is available, linking to reports describing the datasets’ algorithmic basis, validation results, format, uncer- tainty information and experimental use in trial climate applications. Future versions of the datasets will span at least 1982–2015, better addressing the need in many climate applications for stable records of global SST that are at least 30 years in length.

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MAGIC populations represent one of a new generation of crop genetic mapping resources combining high genetic recombination and diversity. We describe the creation and validation of an eight-parent MAGIC population consisting of 1091 F7 lines of winter-sown wheat (Triticum aestivum L.). Analyses based on genotypes from a 90,000-single nucleotide polymorphism (SNP) array find the population to be well-suited as a platform for fine-mapping quantitative trait loci (QTL) and gene isolation. Patterns of linkage disequilibrium (LD) show the population to be highly recombined; genetic marker diversity among the founders was 74% of that captured in a larger set of 64 wheat varieties, and 54% of SNPs segregating among the 64 lines also segregated among the eight founder lines. In contrast, a commonly used reference bi-parental population had only 54% of the diversity of the 64 varieties with 27% of SNPs segregating. We demonstrate the potential of this MAGIC resource by identifying a highly diagnostic marker for the morphological character "awn presence/absence" and independently validate it in an association-mapping panel. These analyses show this large, diverse, and highly recombined MAGIC population to be a powerful resource for the genetic dissection of target traits in wheat, and it is well-placed to efficiently exploit ongoing advances in phenomics and genomics. Genetic marker and trait data, together with instructions for access to seed, are available at http://www.niab.com/MAGIC/.

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This study describes a simple technique that improves a recently developed 3D sub-diffraction imaging method based on three-photon absorption of commercially available quantum dots. The method combines imaging of biological samples via tri-exciton generation in quantum dots with deconvolution and spectral multiplexing, resulting in a novel approach for multi-color imaging of even thick biological samples at a 1.4 to 1.9-fold better spatial resolution. This approach is realized on a conventional confocal microscope equipped with standard continuous-wave lasers. We demonstrate the potential of multi-color tri-exciton imaging of quantum dots combined with deconvolution on viral vesicles in lentivirally transduced cells as well as intermediate filaments in three-dimensional clusters of mouse-derived neural stem cells (neurospheres) and dense microtubuli arrays in myotubes formed by stacks of differentiated C2C12 myoblasts.