13,549 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
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
Phytophthora nicotianae e Rhizoctonia solani: dois novos patógenos da vinca no Brasil.
bitstream/CNPH-2009/33351/1/bpd_30.pd
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
Experimental Determination of Thermal Entanglement in Spin Clusters using Magnetic Susceptibility Measurements
The present work reports an experimental observation of thermal entanglement
in a clusterized spin chain formed in the compound NaCuSiO.
The presence of entanglement was investigated through two measured quantities,
an Entanglement Witness and the Entanglement of Formation, both derived from
the magnetic susceptibility. It was found that pairwise entanglement exists
below K. Tripartite entanglement was also observed below K. A theoretical study of entanglement evolution as a function of applied
field and temperature is also presented.Comment: Submited to Phys. Rev.
Entanglement and Bell's inequality violation above room temperature in metal carboxylates
In the present work we show that a special family of materials, the metal
carboxylates, may have entangled states up to very high temperatures. From
magnetic susceptibility measurements, we have estimated the critical
temperature below which entanglement exists in the cooper carboxylate
\{Cu(OCH)\}\{Cu(OCH)(2-methylpyridine)\}, and we have
found this to be above room temperature ( K). Furthermore, the
results show that the system remains maximally entangled until close to K and the Bell's inequality is violated up to nearly room temperature
( K)
Influência de aléias de leguminosas arbóreas na infestação de bicho-mineiro em cafeeiro.
O bicho-mineiro, Leucoptera coffeella (Guérin - Mèneville, 1842) (Lepidoptera: Lyonetiidae), é talvez a principal praga do cafeeiro (Coffea spp.) na atualidade, principalmente nas regiões de temperaturas mais elevadas e de maior déficit hídrico. Vários estudos indicam que a abundância e diversidade de insetos dentro de um campo podem estar intimamente relacionadas com a natureza da vegetação circundante. Considerando o exposto, foi objetivo deste trabalho observar o efeito de espécies de leguminosas arbóreas utilizadas como quebra-ventos (aléias) sobre os aspectos fitossanitários do cafeeiro. As leguminosas utilizadas foram: o Guandu (Cajanus cajan Millsp.), Bracatinga (Mimosa scabrella Benth.), Leucena (Leucaena leucocephala (Lam.) De Wit) e Acácia (Acacia mangium Willd.), plantadas perpendiculares ao sentido dos ventos predominantes. Os resultados parciais, obtidos em 2003, 2004, 2005 e 2006, mostram que a menor porcentagem de folhas com minas intactas foi observada nos cafeeiros sob Leucena e Guandu e também a menor porcentagem de minas predadas. Os cafeeiros sob Leucena e Guandu apresentaram nível de controle (NC) para o bicho-mineiro (30% de folhas minadas sem sinais de predação) no final de agosto enquanto que aqueles sob Acácia e Bracatinga foram semelhantes à testemunha e apresentaram NC bem mais cedo, no mês de junho
Hyaluronan receptors as mediators and modulators of the tumor microenvironmen
The tumor microenvironment (TME) is a dynamic and complex matter shaped by heterogenous cancer and cancer-associated cells present at the tumor site. Hyaluronan (HA) is a major TME component that plays pro-tumorigenic and carcinogenic functions. These functions are mediated by different hyaladherins expressed by cancer and tumor-associated cells triggering downstream signaling pathways that determine cell fate and contribute to TME progression towards a carcinogenic state. Here, we review the interaction of HA with several cell-surface hyaladherins â CD44, RHAMM, TLR2 and 4, LYVE-1, HARE and layilin. We discuss the signaling pathways activated by these interactions and the respective response of different cell populations within the TME, and the modulation of the TME. Potential cancer therapies via targeting these interactions are also briefly discussed.The authors thank the Portuguese FCT and FSE (Grants no: SFRH/BD/114847/2016, PTDC/NAN-MAT/28468/2017, PTDC/CTM-REF/0022/2020) for providing financial support to this project
Syndemic contexts: findings from a review of research on non-communicable diseases and interviews with experts
Background Syndemics are characterized by the clustering of two or more health conditions, their adverse interaction, and contextual factors that create the conditions for clustering and/or interaction that worsens health outcomes. Studying syndemics entails drawing on diverse disciplines, including epidemiology and anthropology. This often means collaboration between researchers with different scholarly backgrounds, who share and – ideally – integrate their findings. Objective This article examines how context within syndemics has been defined and studied. Methods A literature review of empirical studies focusing on syndemics involving non-communicable diseases (NCDs) and mental health conditions was conducted and the full text of 13 articles was analyzed. The review was followed-up with semi-structured interviews with 11 expert researchers working in the field. Results The review and interviews highlighted a relatively consistent definition of syndemics. The reviewed studies of NCD-related syndemics tended to focus on micro-level context, suggesting a need to analyze further underlying structural factors. In their syndemics research, respondents described working with other disciplines and, although there were some challenges, welcomed greater disciplinary diversity. Methodological gaps, including a lack of mixed methods and longitudinal studies, were identified, for which further interdisciplinary collaborations would be beneficial. Conclusions NCD-related syndemics research would benefit from further analysis of structural factors and the interconnections between syndemic components across multiple levels, together with more ambitious research designs integrating quantitative and qualitative methods. Research on the COVID-19 pandemic can benefit from a syndemics approach, particularly to understand vulnerability and the unequal impacts of this public health crisis
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