3,138 research outputs found
Regular string-like braneworlds
In this work, we propose a new class of smooth thick string-like braneworld
in six dimensions. The brane exhibits a varying brane-tension and an
asymptotic behavior. The brane-core geometry is parametrized by the Bulk
cosmological constant, the brane width and by a geometrical deformation
parameter. The source satisfies the dominant energy condition for the
undeformed solution and has an exotic asymptotic regime for the deformed
solution. This scenario provides a normalized massless Kaluza-Klein mode for
the scalar, gravitational and gauge sectors. The near-brane geometry allows
massive resonant modes at the brane for the state and nearby the brane for
.Comment: 14 pages, 12 figures. Some modifications to match the published
version in EPJ
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A Hidden Complication of Pigtail Catheter Insertion
Pigtail catheters have emerged as an effective and less morbid alternative to traditional chest tubes for evacuation of pleural air. Rare complications in the literature have been reported. We report a case of a 92-year-old male who presented with dyspnea and shock, noted to have a pneumothorax requiring tube thoracostomy. Computed tomography demonstrated pigtail within the lung parenchyma. We discuss the implications of this occurrence
On Mixed Convection in a Horizontal Channel, Viscous Dissipation and Flow Duality
The conditions defining a stationary fluid flow may lead to a multiplicity of solutions. This circumstance is widely documented in the literature when mixed convection in a vertical channel or duct is accompanied by an important effect of viscous dissipation. Usually, there are double stationary solutions with a parallel velocity field which satisfy given temperature boundary conditions and with a prescribed mass flow rate. However, in a vertical internal flow, the dual solutions can be determined only numerically as they do not have a closed analytical form. This study shows that, in a horizontal channel, stationary mixed convection with viscous dissipation shows up dual flow branches whose mathematical expressions can be determined analytically. The features of these dual flows are discussed
Spacetime could be simultaneously continuous and discrete in the same way that information can
There are competing schools of thought about the question of whether
spacetime is fundamentally either continuous or discrete. Here, we consider the
possibility that spacetime could be simultaneously continuous and discrete, in
the same mathematical way that information can be simultaneously continuous and
discrete. The equivalence of continuous and discrete information, which is of
key importance in information theory, is established by Shannon sampling
theory: of any bandlimited signal it suffices to record discrete samples to be
able to perfectly reconstruct it everywhere, if the samples are taken at a rate
of at least twice the bandlimit. It is known that physical fields on generic
curved spaces obey a sampling theorem if they possess an ultraviolet cutoff.
Most recently, methods of spectral geometry have been employed to show that
also the very shape of a curved space (i.e., of a Riemannian manifold) can be
discretely sampled and then reconstructed up to the cutoff scale. Here, we
develop these results further, and we here also consider the generalization to
curved spacetimes, i.e., to Lorentzian manifolds
Evidence for entanglement at high temperatures in an engineered molecular magnet
The molecular compound
[Fe(-oxo)(CHN)(CO)]
was designed and synthesized for the first time and its structure was
determined using single-crystal X-ray diffraction. The magnetic susceptibility
of this compound was measured from 2 to 300 K. The analysis of the
susceptibility data using protocols developed for other spin singlet
ground-state systems indicates that the quantum entanglement would remain at
temperatures up to 732 K, significantly above the highest entanglement
temperature reported to date. The large gap between the ground state and the
first-excited state (282 K) suggests that the spin system may be somewhat
immune to decohering mechanisms. Our measurements strongly suggest that
molecular magnets are promising candidate platforms for quantum information
processing
TECENDO Atividades Entre Valores, Tramas, Saberes E urdiduras: a Contribuição da Ergologia na Análise da Situação de Trabalho no Contexto da Economia solidária
RESUMO
Esta dissertação objetivou conhecer os saberes e valores da atividade no
contexto da Economia Solidária. Através de conceitos da Ergologia trouxemos
para o contexto da Economia Solidária as implicações normativas e as
ressignificações que nos possibilitou analisar as práticas observadas no cotidiano
da cooperativa que figurou como pano de fundo para nosso estudo, fazendo
circular saberes. Salientamos que entendemos o saber enquanto algo histórico, já
que sua produção vincula-se sempre enquanto possibilidade de criação. A partir
das demandas que acompanham o movimento do vivo, do pulsar, negamos um
pressuposto de neutralidade e passividade nas análises efetuadas no trabalho.
Por atividade, compreendemos o processo no espaço-tempo que põe em debate
as normas de quem realiza visando atingir os objetivos colocados, entre o trabalho
prescrito e o trabalho realizado, considerando os valores e saberes nesse
processo. Para a produção de dados utilizamos observação direta da situação de
trabalho, conversas com os trabalhadores enquanto realizavam suas tarefas; nos
corredores e intervalos de trabalho, questionário autopreenchido e diário de
campo. Na análise qualitativa dos dados produzidos, definimos as seguintes
categorias para nortearem nossa pesquisa: sustentabilidade econômica,
autogestão, solidariedade, saberes, valores e sustentabilidade ambiental. Os
resultados apontaram como tais valores compareciam no cotidiano de trabalho da
cooperativa, entendendo a atividade, enquanto debate destes valores.
Ressaltamos uma heterogeneidade de práticas com diferenças sutis na
organização do trabalho em questão, mediante a constatação de que, embora a
Economia Solidária desenhe pressupostos básicos que a diferencie no
entendimento que se faz do trabalho sob o paradigma capitalista, no dia a dia, nos
deparamos com a dificuldade de manter o empreendimento economicamente
ativo, mediante exigências legais e fiscais, entre outras. E como os trabalhadores
através de renormatizações lidam com as exigências colocadas. Dessa
forma, esperou-se contribuir para o estudo da Ergologia e da Economia Solidária.
Palavras-chaves: Economia Solidária, Ergologia, Valores, Saberes
Domain-specific trust for context-aware BDI Agents: preliminary work
Context-aware systems are capable of perceiving the physical environment where they are deployed and adapt
their behavior accordingly. Multiagent systems based on the BDI architecture can be used to process contextual
information in the form of beliefs. Contextual information can be divided and structured in the form of
information domains. Information and experience sharing enables a single agent to receive data on different
information domains from another agent. In this scenario, establishing a trust model between agents can take
into account the relative perceptions each agent has of the others, as well as different trust degrees for different
information domains. The objective of this work is to adapt an epistemic model to be used by agents with their
belief revision in order to establish a mechanism of domain-specific relative trust attribution. Such mechanism
will allow for each agent to possess different trust degrees associated with other agents regarding different
information domains.info:eu-repo/semantics/publishedVersio
Ductus venosus agenesis and fetal malformations: what can we expect? - a systematic review of the literature
Background: The ductus venosus agenesis (DVA) is a rare condition with a variable prognosis that relies partly on the presence of associated conditions. The purpose of our study was to analyze the literature regarding the postnatal outcome of fetuses with DVA associated with fetal malformations, in order to discuss the best management options for couples. Methods: We performed a systematic review of the literature of MEDLINE and SCOPUS electronic databases in a 25-year period from 1992 to September 2017. Results: We found 340 cases of DVA associated with fetal abnormalities. The most common chromosomal abnormalities were: monosomy X (12/48, 25%), trisomy 21 (11/48, 22.9%) and trisomy 18 (6/48, 12.5%). From the 340 cases with DVA, in 31 cases the umbilical venous shunt type was not reported. Of the fetuses, 60.8% (188/309) had an extrahepatic umbilical venous drainage while 39.2% (121/309) presented an intrahepatic connection. The DVA was associated in 71 cases (23.0%) with cardiac abnormalities, in 82 cases (26.5%) with extracardiac abnormalities and in 85 cases (27.5%) with both cardiac and extracardiac abnormalities. Conclusion: DVA associated with both cardiac and extracardiac malformations may confer a poorer fetal outcome, a clinically relevant fact that should clarify what can be expected from this entity and help prenatal counseling
Sustainability assessment of future-oriented scenarios: a review of data modelling approaches in Life Cycle Assessment
Steering policy-making processes and business long term strategies entails tasks such as e.g. setting up sound environmental long term
objectives and targets, assessing implications, and comparing options. To best run these tasks in the context of sustainability
assessment, two fundamental ingredients are indispensable: life cycle thinking and analysis of future-oriented scenarios.
Considering the whole life cycle of goods and services is necessary to avoid the shifting of problems from one life cycle stage to another,
from one geographic area to another and from one environmental medium or protection target to another.
Given the proliferation of life cycle thinking-based data modelling approaches, a review was conducted to detect where we stand in
defining and framing life cycle thinking-based approaches and related data modelling approaches, what their key features are, and how
mature they are. In addition, a scientific workshop was arranged to further discuss data modelling approaches and to screen how
Environmental Footprint methodologies can be used to assess future-oriented scenarios.
This review represents a stepping stone towards recommendations for sustainability assessment of future-oriented scenarios.JRC.H.8-Sustainability Assessmen
TEMPORAL AND SPATIAL DISTRIBUTION OF POACEAE POLLEN IN AREAS OF SOUTHERN UNITED KINGDOM, SPAIN AND PORTUGAL
Overall, longer Poaceae pollen seasons coincided with earlier pollen season start dates. Winter rainfall noticeably affects
the intensity of Poaceae pollen seasons in Mediterranean areas, but this was not as important in Worcester. Weekly data
from Worcester followed a similar pattern to that of Badajoz and Évora but at a distance of more than 1500 km and 4-5
weeks later
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