Analytical study of tunneling times in flat histogram Monte Carlo

We present a model for the dynamics in energy space of multicanonical simulation methods that lends itself to a rather complete analytic characterization. The dynamics is completely determined by the density of states. In the \pm J 2D spin glass the transitions between the ground state level and the first excited one control the long time dynamics. We are able to calculate the distribution of tunneling times and relate it to the equilibration time of a starting probability distribution. In this model, and possibly in any model in which entering and exiting regions with low density of states are the slowest processes in the simulations, tunneling time can be much larger (by a factor of O(N)) than the equilibration time of the probability distribution. We find that these features also hold for the energy projection of single spin flip dynamics.Comment: 7 pages, 4 figures, published in Europhysics Letters (2005

Mass, angular-momentum, and charge inequalities for axisymmetric initial data

We present the key elements of the proof of an upper bound for angular-momentum and charge in terms of the mass for electro-vacuum asymptotically flat axisymmetric initial data sets with simply connected orbit space

Knowledge and attitude towards the gradual reduction of salt in bread – an online survey

Aim: Assess knowledge and attitude towards the gradual reduction of salt in bread and the potential impact on eating habits of children (6-18 years) and their families, as part as a Health Impact Assessment pilot study.N/

A Dain Inequality with charge

We prove an upper bound for angular-momentum and charge in terms of the mass for electro-vacuum asymptotically flat axisymmetric initial data sets with simply connected orbit space

Tools for online collaboration: do they contribute to improve teamwork?

In the last decades, the fast growth of Information and Communication Technologies changed our way to communicate and share information. Traditional groups or teams frequently give way to virtual teams, working with tools for online collaboration. Interaction between persons geographically dispersed has become easier. However, the use of new collaboration tools can also bring many challenges. Some technologies, like e-mail, can create delays on reply or even misunderstandings, case the message is not well understood by the recipient. Can these new technologies improve the productivity and enhance the creativity between group members, improving also their confidence and motivation? Although virtual teams have a high capacity to adapt to constant market changes, personal interactions are still important, mainly to clarify tasks and goals. The main purpose of this study is to understand how tools for online collaboration may improve the productivity (and enhance creativity) in teamwork. This study was conducted through an internet platform and the survey was hosted online by SurveyMonkey.com. We intended to verify, among other questions, what users think about different collaboration tools, how often they use these tools, and how they perceive these technologies as adequate ways to communicate, to work with, and to improve productivity. Findings show that e-mail is the most used tool, and personal contact is still more important for teamwork than any tools for online collaboration. Our results contribute to perceive in what extent collaboration tools are indeed an asset or a barrier in teamwork.info:eu-repo/semantics/publishedVersio

Using soil and canopy temperature to support efficient management of irrigated vineyards

Extreme heat and drought events are becoming more frequent and erratic in Mediterranean Europe. Better comprehension of spatial and temporal dynamics of heat fluxes and thermal microclimate in vineyards can support vineyard’s management and minimize the impact of climate variability. Field experiments were carried out in South Portugal with two red cvs. Touriga Nacional and Aragonez (syn. Tempranillo) under deficit irrigation. Canopy temperature (Tc) is a robust predictor of plant water status, especially when measured under more stressful conditions. In parallel, soil temperature (TS) had a positive influence on TC especially at the cluster zoneinfo:eu-repo/semantics/publishedVersio

VRIO: Static or dynamic?

During the 1980s, the principal concern of theorists in what regarded strategic management was linked to the analysis of the external environment. However, many researchers defend that considering the turbulence of today’s business environment with the technology’ advancement, the ever-changing industries and with an ever continuingly-increasing reduction in the time-frame of competitive advantage, a resource-based view has been gaining its own space regarding strategic formulation. Despite of the model’s capability, the theory has received diverse criticism during the last years, which we believe that some of these criticisms deserve to be analyzed. Therefore, the present article intends to illustrate a new theoretical basis for the analysis of the resources and capabilities in order to explain the advantages of applying a conceptual model that articulates the VRIO framework, initially developed by Barney (1991) with a new conceptual model that allow companies to perceive the dynamism of the company’s competitive advantage through the inclusion of the values, dynamic capabilities and governance concepts from the VDS acronym. The article is subdivided into six parts, the first part is referent to the theoretical exploitation of the RBV dematerialized in the creation of the VRIO model. The second part presents the main criticisms existent in the literature regarding the model and its limitations. The third, fourth and fifth parts refer to the approach in order to achieve the articulation between the VRIO model and the three additional parameters. In the sixth part, the new model will be presented and lastly, some considerations will be presented regarding this subject.info:eu-repo/semantics/submittedVersio

Estudo comparativo da artrodese posterolateral e PLIF no tratamento da espondilolistesis degenerativa grau I ou II ? análise de 124 casos

Objetivo: Posterior Lumbar Interbody Fusion (PLIF) ou artrodese posterolateral (APL) são técnicas cirúrgicas válidas na espondilolistese degenerativa. Alterações biomecânicas no nível adjacente à artrodese aceleram alterações degenerativas. Na literatura discute-se o tratamento adequado. Este estudo comparativo avalia clínica, taxa de fusão, complicações, alterações degenerativas e instabilidade no nível adjacente. Material e Métodos: Retrospectivamente foram analisadas espondilolisteses degenerativas grau I e II de Meyerding tratadas com PLIF ou APL de Janeiro 2000 a Dezembro 2010 num total de 124 doentes, 45 PLIF e 79 APL. Recorreu-se à escala visual analógica (VAS), Oswestry Disability Index (ODI) e Short Form-36 (SF-36). No PLIF foi determinada artrodese por estabelecimento de pontes ósseas estáveis. A instabilidade na APL foi definida quando osteolise adjacente aos parafusos, deslizamento ou angulação no nível da fusão. Resultados: O follow-up foi 4.5±2.7 e 3.9±2.6 anos (1-11 anos) no PLIF e APL, respectivamente. Ocorreu fusão em 93.3% no PLIF e 74.7% na APL (p=0.008). O PLIF apresenta superioridade no VAS pós-operatório (p=0.01) e variação geral (p=0.002). O ODI pós-operatório no PLIF foi menor (p<0.001) e 2.2% permanecem com disfunção severa comparativamente com 19% na APL. O PLIF é superior em escalas do SF-36: Função Física (p=0.034), Limitação Emocional (p=0.037), Função Social (p=0.05) e Saúde Geral (p=0.02). A taxa de complicações foi 4.4% no PLIF e 12.6% na APL (p=0.2). Ambas as técnicas desenvolveram doença do disco adjacente. Conclusões: Em ambos os grupos verifica-se melhoria da qualidade de vida, no entanto, a médio prazo o PLIF mostra superioridade. Instabilidade pré-operatória pode ser indicativa da eleição de PLIF

Rendimento de derruba e extração mecanizada em florestas de terra firme da Amazônia.

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