Four-fold structure of vortex core states in Bi2Sr2CaCu2O8 (Bi2212)

We present a detailed study of vortex core spectroscopy in slightly overdoped Bi2Sr2CaCu2O8 using a low temperature scanning tunneling microscope. Inside the vortex core we observe a four-fold symmetric modulation of the local density of states with an energy-independent period of (4.3\pm 0.3)a0. Furthermore we demonstrate that this square modulation is related to the vortex core states which are located at ~6 meV. Since the core-state energy is proportional to the superconducting gap magnitude, our results strongly suggest the existence of a direct relation between the superconducting state and the local electronic modulations in the vortex core.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

Full contract verification for ATL using symbolic execution

The Atlas Transformation Language (ATL) is currently one of the most used model transformation languages and has become a de facto standard in model-driven engineering for implementing model transformations. At the same time, it is understood by the community that enhancing methods for exhaustively verifying such transformations allows for a more widespread adoption of model-driven engineering in industry. A variety of proposals for the verification of ATL transformations have arisen in the past few years. However, the majority of these techniques are either based on non-exhaustive testing or on proof methods that require human assistance and/or are not complete. In this paper, we describe our method for statically verifying the declarative subset of ATL model transformations. This verification is performed by translating the transformation (including features like filters, OCL expressions, and lazy rules) into our model transformation language DSLTrans. As we handle only the declarative portion of ATL, and DSLTrans is Turing-incomplete, this reduction in expressivity allows us to use a symbolic-execution approach to generate representations of all possible input models to the transformation. We then verify pre-/post-condition contracts on these representations, which in turn verifies the transformation itself. The technique we present in this paper is exhaustive for the subset of declarative ATL model transformations. This means that if the prover indicates a contract holds on a transformation, then the contract’s pre-/post-condition pair will be true for any input model for that transformation. We demonstrate and explore the applicability of our technique by studying several relatively large and complex ATL model transformations, including a model transformation developed in collaboration with our industrial partner. As well, we present our ‘slicing’ technique. This technique selects only those rules in the DSLTrans transformation needed for contract proof, thereby reducing proving timeComisión Interministerial de Ciencia y Tecnología TIN2015-70560-RJunta de Andalucía P10-TIC-5906Junta de Andalucía P12-TIC-186

Fully Verifying Transformation Contracts for Declarative ATL

The Atlas Transformation Language (ATL) is today a de-facto standard in model-driven development. It is understood by the community that methods for exhaustively verifying such transformations provide an important pillar for achieving a stronger adoption of model-driven development in industry. In this paper we propose a method for verifying ATL model transformations by translating them into DSLTrans, a transformation language with limited expressiveness. Pre-/postcondition contracts are then verified on the resulting DSLTrans specification using a symbolic-execution property prover. The technique we present in this paper is exhaustive for the declarative ATL subset, meaning that if a contract holds, it will hold when any input model is passed to the ATL transformation being checked. We explore the scalability of our technique using a set of examples, including a model transformation developed in collaboration with our industrial partner.European Commission ICT Policy Support Programme 31785

A century of warfare shoots holes in anti-Caulerpa campaign

Effort to have all varieties of the marine alga Caulerpa taxifolia listed as noxious weeds hinges on the argument that the alga's proliferation in the Mediterranean Sea is a cause and not a consequence of environmental degradation. Until now, the occurrence of two populations in a pristine part of the northern Mediterranean near the island of Porquerolles has upheld this claim. Here we show that the alga's development at Porquerolles is indeed a consequence of environmental degradation caused by military weapons' impacts on seagrass beds during the last century. The available data show that substratum enrichment plays a key role in fostering development of Caulerpa, irrespective of whether this results directly from pollution or from the impacts of pollution and other anthropogenic factors on benthic vegetation cover

Análise de conteúdo a sites de franchising em Portugal: traços de personalidade das empresas franchisadoras .

Mestrado em MarketingUm grande número de estudos académicos tem-se dedicado à conceptualização e medição do fenómeno "reputação da organização." Para este efeito, várias abordagens têm sido seguidas na identificação de indicadores de escalas de reputação da organização. A abordagem da personificação da marca é utilizada desde há muitos anos na identificação de associações à marca. Recentemente, houve interesse renovado nesta abordagem tendo surgido a escala de personalidade da marca de Aaker ( 1997) e, mais tarde, uma outra escala aplicada especificamente à marca institucional ( Davies et al. 2003). Qualquer destas escalas é multidimensional tendo os autores testado a sua validade em culturas anglo-saxónicas. Contudo, a generalização de uma escala para contextos culturais diferentes daqueles onde foi construída pode encontrar dificuldades relacionadas com a sua validade. Em Portugal está actualmente em curso um projecto que visa o desenvolvimento de uma escala de reputação da organização adaptada à realidade e cultura portuguesas. Este estudo tem um carácter exploratório e insere-se nesse projecto mais amplo. Especificamente, o seu foco é investigar a adequação dos indicadores das escalas de personalidade Aaker ( 1997) e Davies et al. (2003) ao contexto cultural português. Foi pesquisada a comunicação institucional incluída em sites da Internet de empresas franchisadoras que actuam em Portugal. Através da técnica de análise de conteúdo identificaram-se nesses textos os traços de personalidade incluídos na escala de personalidade da marca de Aaker ( 1997) e na escala de personalidade da marca institucional de Davies et al. (2003). Os resultados de frequência estatística mostram que 81,9% dos indicadores das escalas são utilizados nos sites estudados. É sugerido que as organizações atribuem níveis de importância aos traços de personalidade em função do valor que julgam que eles têm no desenvolvimento de reacções emocionais positivas sobre a marca institucional nos seus stakeholders. Assim, estes níveis de importância poderão ser utilizados para ajudar a justificar a adequação dos indicadores das escalas de personalidade Aaker ( 1997) e Davies et al. (2003) ao contexto cultural português.A substantial number of academic studies have been devoted to the conceptualization and measurement of corporate reputation. To accomplish this purpose several approaches have been followed to identify indicators of corporate reputation scales. The brand personification metaphor has been used for many years to identify brand associations. Following a renewed interest in this approach Aaker ( 1997) developed a brand personality scale and, later, another scale specifically relevant to the corporate brand was designed by Davies et al. (2003). Both scales are multidimensional and were tested for validity in the American and British contexts. However, the potential generalization of a scale to cultural contexts different to those were it was developed should be assessed for validity. It is currently in progress in Portugal a project with the purpose of developing a corporate personality scale adapted to the Portuguese reality and culture. The current study has an exploratory nature and it is under that wider project. Specifically, the focus of this study is to investigate the adequacy of the scale items of two personality scales — Aaker ( 1997) and Davies at al. (2003) — to the Portuguese cultural context. The research analysed corporate communication texts included in the Internet sites of franchising organizations that operate in Portugal. A content analysis of those texts was performed to identify the personality traits included in the brand personality scale of Aaker ( 1997) and the corporate personality scale of Davies et al. (2003). The results of statistical frequencies show that 81,9% of the scale items were used in the researched sites. Results suggest that organizations assign different innportance leveis to each personality trait which might express the perception that organizations have towards the value of each personality trait for the development of positive emotional reactions about the corporate brand by their stakeholders. Thus, these rankings might contribute to assess the adequacy of each researched personality trait to the Portuguese cultural context.N/

Exploring the Influence of Price and Convenience on Perceived Usefulness of On-line Banking within the TAM Framework: A Cross National (Canada and Spain) Decision Model

Nowadays, the Internet is a powerful mean to complement the traditional marketing channels used by banks. Based on the Technology Acceptance Model, this paper explores the importance of two external latent variables—‘Price’ and ‘Convenience’ —as antecedents of ‘Perceived Usefulness’ and consumer acceptance of on-line banking in a Canadian and Spanish environment; the results highlight the predictive power and accuracy of the model cross-nationally. In fact, the findings were quite similar in the Canadian and Spanish samples, and stress that ‘Perceived Usefulness’ and ‘Attitude’ are the key drivers of the consumers’ on-line banking acceptance. Conclusions and recommendations for future research are also provided

A Re-Examination of Hebbian-Covariance Rules and Spike Timing-Dependent Plasticity in Cat Visual Cortex in vivo

Spike timing-dependent plasticity (STDP) is considered as an ubiquitous rule for associative plasticity in cortical networks in vitro. However, limited supporting evidence for its functional role has been provided in vivo. In particular, there are very few studies demonstrating the co-occurrence of synaptic efficiency changes and alteration of sensory responses in adult cortex during Hebbian or STDP protocols. We addressed this issue by reviewing and comparing the functional effects of two types of cellular conditioning in cat visual cortex. The first one, referred to as the “covariance” protocol, obeys a generalized Hebbian framework, by imposing, for different stimuli, supervised positive and negative changes in covariance between postsynaptic and presynaptic activity rates. The second protocol, based on intracellular recordings, replicated in vivo variants of the theta-burst paradigm (TBS), proven successful in inducing long-term potentiation in vitro. Since it was shown to impose a precise correlation delay between the electrically activated thalamic input and the TBS-induced postsynaptic spike, this protocol can be seen as a probe of causal (“pre-before-post”) STDP. By choosing a thalamic region where the visual field representation was in retinotopic overlap with the intracellularly recorded cortical receptive field as the afferent site for supervised electrical stimulation, this protocol allowed to look for possible correlates between STDP and functional reorganization of the conditioned cortical receptive field. The rate-based “covariance protocol” induced significant and large amplitude changes in receptive field properties, in both kitten and adult V1 cortex. The TBS STDP-like protocol produced in the adult significant changes in the synaptic gain of the electrically activated thalamic pathway, but the statistical significance of the functional correlates was detectable mostly at the population level. Comparison of our observations with the literature leads us to re-examine the experimental status of spike timing-dependent potentiation in adult cortex. We propose the existence of a correlation-based threshold in vivo, limiting the expression of STDP-induced changes outside the critical period, and which accounts for the stability of synaptic weights during sensory cortical processing in the absence of attention or reward-gated supervision

Interaction between HFE and haptoglobin polymorphisms and its relation with plasma glutathione levels in obese children

Short CommunicationObesity among children has emerged as a serious public health problem. The growing prevalence of childhood obesity has led to the appearance of serious complications, including a chronic systemic inflammation associated with oxidative stress. In the present study, we analysed the interaction between two genes related with iron metabolism - HFE and haptoglobin – and the plasmatic concentration of glutathione, as a way to evaluate the antioxidant response capacity in obesity. To achieve this, 118 obese children and 89 eutrophic children were recruited for the study. Results showed that although obese children present a significantly decreased tGSH levels, once we analysed separately children based on their haptoglobin phenotype, the decreased tGSH levels is significant only for the Hp 2 allele. Additionally, Hp 2.2 obese children carrying H63D polymorphism show significantly lower tGSH/GSSG values. Our results found an association of haptoglobin and HFE with oxidative stress in childhood obesity.The authors are grateful to all study participants and their families and would like to thank the Instituto de Investigação Científica Bento da Rocha Cabral for financial support.info:eu-repo/semantics/publishedVersio