20,459 research outputs found
Phase diagram of a 2D Ising model within a nonextensive approach
In this work we report Monte Carlo simulations of a 2D Ising model, in which
the statistics of the Metropolis algorithm is replaced by the nonextensive one.
We compute the magnetization and show that phase transitions are present for
. A phase diagram (critical temperature vs. the entropic
parameter ) is built and exhibits some interesting features, such as phases
which are governed by the value of the entropic index . It is shown that
such phases favors some energy levels of magnetization states. It is also
showed that the contribution of the Tsallis cutoff is essential to the
existence of phase transitions
Observational Constraints on Silent Quartessence
We derive new constraints set by SNIa experiments (`gold' data sample of
Riess et al.), X-ray galaxy cluster data (Allen et al. Chandra measurements of
the X-ray gas mass fraction in 26 clusters), large scale structure (Sloan
Digital Sky Survey spectrum) and cosmic microwave background (WMAP) on the
quartessence Chaplygin model. We consider both adiabatic perturbations and
intrinsic non-adiabatic perturbations such that the effective sound speed
vanishes (Silent Chaplygin). We show that for the adiabatic case, only models
with equation of state parameter are allowed: this
means that the allowed models are very close to \LambdaCDM. In the Silent case,
however, the results are consistent with observations in a much broader range,
-0.3<\alpha<0.7.Comment: 7 pages, 12 figures, to be submitted to JCA
Phytophthora nicotianae e Rhizoctonia solani: dois novos patógenos da vinca no Brasil.
bitstream/CNPH-2009/33351/1/bpd_30.pd
Vascularization in bone tissue engineering : physiology, current strategies, major hurdles and future challenges
The lack of a functional vascular supply has, to a large extent, hampered the whole range of
clinical applications of ‘successful’ laboratory-based bone tissue engineering strategies. To the
present, grafts have been dependent on post-implant vascularization, which jeopardizes graft
integration and often leads to its failure. For
this reason, the development of strategies that
could effectively induce the establishment of a
microcirculation in the engineered constructs
has become a major goal for the tissue engineering
research community. This review
addresses the role and importance of the development
of a vascular network in bone tissue
engineering and provides an overview of the
most up to date research efforts to develop such
a network.M. I. Santos would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her Ph.D. grant (SFRH/BD/13428/2003). This work was partially supported by FCT through funds from POCTI and/or FEDER programs and by the European Union funded STREP Project HIPPOCRATES (NMP3-CT-2003-505758). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283). The authors also acknowledge Gabriela A. Silva for critically reading the manuscript
Carotid Artery Dissection
A dissecção da artéria carótida interna é uma causa de AVC isquémico, particularmente em doentes jovens, sem aparentes factores de risco cérebro-vasculares. Métodos: Os autores descrevem o quadro clínico e achados imagiológicos (TAC, RMN e angiografia de subtracção digital) de cinco doentes internados consecutivamente na Unidade Cérebro-Vascular do Hospital de S. José, num período de dois meses, com o diagnóstico de oclusão da artéria carótida interna por provável dissecção. Discussão: O conjunto de casos clínicos apresentados salienta a heterogeneidade de formas de apresentação desta patologia, quer do ponto de vista clínico, quer imagiológico
Second Generation of 'Miranda Procedure' for CP Violation in Dalitz Studies of B (\& D \& \tau) Decays
The `Miranda Procedure' proposed for analyzing Dalitz plots for CP
asymmetries in charged B and D decays in a model-independent manner is extended
and refined. The complexity of CKM CP phenomenology through order
is needed in searches for New Dynamics (ND). Detailed analyses of three-body
final states other great advantages: (i) They give us more powerful tools for
deciding whether an observed CP asymmetry rep- resents the manifestation of ND
and its features. (ii) Many advantages can already be obtained by the `Miranda
Procedure' without construction of a detailed Dalitz plot de- scription. (iii)
One studies CP asymmetries independent of production asymmetries. We illustrate
the power of a second generation Miranda Procedure with examples with time
integrated rates for decays to final states as
trial runs with comments on .Comment: 29 pages, 7 figure
Slum health: diseases of neglected populations.
BackgroundUrban slums, like refugee communities, comprise a social cluster that engenders a distinct set of health problems. With 1 billion people currently estimated to live in such communities, this neglected population has become a major reservoir for a wide spectrum of health conditions that the formal health sector must deal with.DiscussionUnlike what occurs with refugee populations, the formal health sector becomes aware of the health problems of slum populations relatively late in the course of their illnesses. As such, the formal health sector inevitably deals with the severe and end-stage complications of these diseases at a substantially greater cost than what it costs to manage non-slum community populations. Because of the informal nature of slum settlements, and cultural, social, and behavioral factors unique to the slum populations, little is known about the spectrum, burden, and determinants of illnesses in these communities that give rise to these complications, especially of those diseases that are chronic but preventable. In this article, we discuss observations made in one slum community of 58,000 people in Salvador, the third largest city in Brazil, to highlight the existence of a spectrum and burden of chronic illnesses not likely to be detected by the formal sector health services until they result in complications or death. Lack of health-related data from slums could lead to inappropriate and unrealistic allocation of health care resources by the public and private providers. Similar misassumptions and misallocations are likely to exist in other nations with large urban slum populations.SummaryContinued neglect of ever-expanding urban slum populations in the world could inevitably lead to greater expenditure and diversion of health care resources to the management of end-stage complications of diseases that are preventable. A new approach to health assessment and characterization of social-cluster determinants of health in urban slums is urgently needed
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