3,838 research outputs found
Finite-size scaling considerations on the ground state microcanonical temperature in entropic sampling simulations
In this work we discuss the behavior of the microcanonical temperature
obtained by means of numerical entropic
sampling studies. It is observed that in almost all cases the slope of the
logarithm of the density of states is not infinite in the ground state,
since as expected it should be directly related to the inverse temperature
. Here we show that these finite slopes are in fact due to
finite-size effects and we propose an analytic expression for the
behavior of when . To
test this idea we use three distinct two-dimensional square lattice models
presenting second-order phase transitions. We calculated by exact means the
parameters and for the two-states Ising model and for the and
states Potts model and compared with the results obtained by entropic sampling
simulations. We found an excellent agreement between exact and numerical
values. We argue that this new set of parameters and represents an
interesting novel issue of investigation in entropic sampling studies for
different models
Harmonic analysis on the Möbius gyrogroup
In this paper we propose to develop harmonic analysis on the Poincaré ball , a model of the n-dimensional real hyperbolic space. The Poincaré ball is the open ball of the Euclidean n-space with radius , centered at the origin of and equipped with Möbius addition, thus forming a Möbius gyrogroup where Möbius addition in the ball plays the role of vector addition in . For any and an arbitrary parameter we study the -translation, the -convolution, the eigenfunctions of the -Laplace-Beltrami operator, the -Helgason Fourier transform, its inverse transform and the associated Plancherel's Theorem, which represent counterparts of standard tools, thus, enabling an effective theory of hyperbolic harmonic analysis. Moreover, when the resulting hyperbolic harmonic analysis on tends to the standard Euclidean harmonic analysis on , thus unifying hyperbolic and Euclidean harmonic analysis. As an application we construct diffusive wavelets on
Building the Brazilian Academic Genealogy Tree
Along the history, many researchers provided remarkable contributions to
science, not only advancing knowledge but also in terms of mentoring new
scientists. Currently, identifying and studying the formation of researchers
over the years is a challenging task as current repositories of theses and
dissertations are cataloged in a decentralized way through many local digital
libraries. Following our previous work in which we created and analyzed a large
collection of genealogy trees extracted from NDLTD, in this paper we focus our
attention on building such trees for the Brazilian research community. For
this, we use data from the Lattes Platform, an internationally renowned
initiative from CNPq, the Brazilian National Council for Scientific and
Technological Development, for managing information about individual
researchers and research groups in Brazil
Differential Internalization of Amphotericin B - Conjugated Nanoparticles in Human Cells and the Expression of Heat Shock Protein 70
Although a variety of nanoparticles (NPs) functionalized with amphotericin B, an antifungal agent widely used in the clinic, have been studied in the last years their cytotoxicity profile remains elusive. Here we
show that human endothelial cells take up high amounts of silica nanoparticles (SNPs) conjugated with amphotericin B (AmB) (SNP-AmB) (65.4 12.4 pg of Si per cell) through macropinocytosis while human fibroblasts internalize relatively low amounts (2.3 0.4 pg of Si per cell) because of their low capacity for macropinocytosis. We further show that concentrations of SNP-AmB and SNP up to 400 mg/mL do not substantially affect fibroblasts. In contrast, endothelial cells are sensitive to low concentrations of NPs
(above 10 mg/mL), in particular to SNP-AmB. This is because of their capacity to internalize high concentration of NPs and high sensitivity of their membrane to the effects of AmB. Low-moderate concentrations
of SNP-AmB (up to 100 mg/mL) induce the production of reactive oxygen species (ROS), LDH release, high expression of pro-inflammatory cytokines and chemokines (IL-8, IL-6, G-CSF, CCL4, IL-1b and CSF2) and high expression of heat shock proteins (HSPs) at gene and protein levels. High concentrations
of SNP-AmB (above 100 ug/mL) disturb membrane integrity and kill rapidly human cells(60% after 5 h). This effect is higher in SNP-AmB than in SNP
Spontaneous Neonatal Humeral Artery Thromboembolism: a Case Report
info:eu-repo/semantics/publishedVersio
Patient-doctor continuity and diagnosis of cancer: electronic medical records study in general practice
This is the final version of the article. Available from Royal College of General Practitioners via the DOI in this record.BACKGROUND: Continuity of care may affect the diagnostic process in cancer but there is little research. AIM: To estimate associations between patient-doctor continuity and time to diagnosis and referral of three common cancers. DESIGN AND SETTING: Retrospective cohort study in general practices in England. METHOD: This study used data from the General Practice Research Database for patients aged ≥40 years with a diagnosis of breast, colorectal, or lung cancer. Relevant cancer symptoms or signs were identified up to 12 months before diagnosis. Patient-doctor continuity (fraction-of-care index adjusted for number of consultations) was calculated up to 24 months before diagnosis. Time ratios (TRs) were estimated using accelerated failure time regression models. RESULTS: Patient-doctor continuity in the 24 months before diagnosis was associated with a slightly later diagnosis of colorectal (time ratio [TR] 1.01, 95% confidence interval [CI] =1.01 to 1.02) but not breast (TR = 1.00, 0.99 to 1.01) or lung cancer (TR = 1.00, 0.99 to 1.00). Secondary analyses suggested that for colorectal and lung cancer, continuity of doctor before the index consultation was associated with a later diagnosis but continuity after the index consultation was associated with an earlier diagnosis, with no such effects for breast cancer. For all three cancers, most of the delay to diagnosis occurred after referral. CONCLUSION: Any effect for patient-doctor continuity appears to be small. Future studies should compare investigations, referrals, and diagnoses in patients with and without cancer who present with possible cancer symptoms or signs; and focus on 'difficult to diagnose' types of cancer.This work was funded by Cancer Research UK (C41384/A13266)
Analise Comparativa Dos Produtos Modis Ecologia Para O Monitoramento Biofisico Ambiental Do Bioma Cerrado
The Brazilian Cerrado is an extensive and complex biome, characterized by rapid and abrupt land cover changes. Due to its dimensions and physiognomic variations, the Cerrado plays an important role regarding the water, energy, and carbon fluxes at both the regional and global scales. Therefore, the correct understanding of the structure and ecological functioning of this biome, particularly in the temporal domain, is of great importance. With this respect, in this study we compared the seasonal response and land cover discrimination of the major MODIS (MODerate resolution Imaging Spectroradiometer) biophysical indices: the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), the leaf area index (LAI), and the fraction of absorbed photosynthetically active radiation (fAPAR). In spite of the fact the four indices showed similar temporal trends, the LAI showed the highest sensitivity to the seasonal variations of the natural and converted landscapes. On the other hand, the NDVI showed the best performance regarding land cover discrimination. Our results suggest a synergistic approach concerning the MODIS biophysical / ecological variables for land cover assessments and environmental monitoring of the Cerrado biome
Field theory of scaling lattice models. The Potts antiferromagnet
In contrast to what happens for ferromagnets, the lattice structure
participates in a crucial way to determine existence and type of critical
behaviour in antiferromagnetic systems. It is an interesting question to
investigate how the memory of the lattice survives in the field theory
describing a scaling antiferromagnet. We discuss this issue for the square
lattice three-state Potts model, whose scaling limit as T->0 is argued to be
described exactly by the sine-Gordon field theory at a specific value of the
coupling. The solution of the scaling ferromagnetic case is recalled for
comparison. The field theory describing the crossover from antiferromagnetic to
ferromagnetic behaviour is also introduced.Comment: 11 pages, to appear in the proceedings of the NATO Advanced Research
Workshop on Statistical Field Theories, Como 18-23 June 200
Universality in Systems with Power-Law Memory and Fractional Dynamics
There are a few different ways to extend regular nonlinear dynamical systems
by introducing power-law memory or considering fractional
differential/difference equations instead of integer ones. This extension
allows the introduction of families of nonlinear dynamical systems converging
to regular systems in the case of an integer power-law memory or an integer
order of derivatives/differences. The examples considered in this review
include the logistic family of maps (converging in the case of the first order
difference to the regular logistic map), the universal family of maps, and the
standard family of maps (the latter two converging, in the case of the second
difference, to the regular universal and standard maps). Correspondingly, the
phenomenon of transition to chaos through a period doubling cascade of
bifurcations in regular nonlinear systems, known as "universality", can be
extended to fractional maps, which are maps with power-/asymptotically
power-law memory. The new features of universality, including cascades of
bifurcations on single trajectories, which appear in fractional (with memory)
nonlinear dynamical systems are the main subject of this review.Comment: 23 pages 7 Figures, to appear Oct 28 201
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