Institution
Universidade Federal de Minas Gerais
Education•Belo Horizonte, Minas Gerais, Brazil•
About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.
Papers published on a yearly basis
Papers
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TL;DR: It is shown that adipocyte platelet-derived growth factor receptor-α-positive progenitors adopt a fibrogenic phenotype in obese mice prone to visceral WAT fibrosis, and that in addition to representing a WAT adipogenic niche, different PDGFRα+ cell subsets modulate obesity-induced Wat fibrogenesis and are associated with loss of metabolic fitness.
170 citations
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TL;DR: This paper introduces a low cost and software-based method for detecting spoofing attempts in face recognition systems and extracts time-spectral feature descriptors from the video that can be understood as a low-level feature descriptor that gathers temporal and spectral information across the biometric sample.
Abstract: Despite important recent advances, the vulnerability of biometric systems to spoofing attacks is still an open problem. Spoof attacks occur when impostor users present synthetic biometric samples of a valid user to the biometric system seeking to deceive it. Considering the case of face biometrics, a spoofing attack consists in presenting a fake sample (e.g., photograph, digital video, or even a 3D mask) to the acquisition sensor with the facial information of a valid user. In this paper, we introduce a low cost and software-based method for detecting spoofing attempts in face recognition systems. Our hypothesis is that during acquisition, there will be inevitable artifacts left behind in the recaptured biometric samples allowing us to create a discriminative signature of the video generated by the biometric sensor. To characterize these artifacts, we extract time-spectral feature descriptors from the video, which can be understood as a low-level feature descriptor that gathers temporal and spectral information across the biometric sample and use the visual codebook concept to find mid-level feature descriptors computed from the low-level ones. Such descriptors are more robust for detecting several kinds of attacks than the low-level ones. The experimental results show the effectiveness of the proposed method for detecting different types of attacks in a variety of scenarios and data sets, including photos, videos, and 3D masks.
170 citations
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24 Feb 2017
TL;DR: In this article, a diagram can be built for disentangling contributions of point-like and line-like defects to the Raman spectra of graphene-related materials embracing, from the topology point of view, all possible structures from perfect to fully disordered sp2 bonded carbons.
Abstract: The transition from graphene to a fully disordered sp2 carbon material can be idealized by either cutting graphene into smaller and smaller pieces, or adding more and more point defects. In other words, from the dimensionality standpoint, defects in two-dimensional (2D) systems can be either one- (1D) or zero-dimensional (0D). From an application point of view, both in terms of bottom-up as well as top-down approaches, the discrimination between these two structural disorder in two-dimensional systems is urgently desired. In graphene, both types of defects produce changes in the Raman spectrum, but identifying separately the contribution from each defect-type has not yet been achieved. Here we show that a diagram can be built for disentangling contributions of point-like and line-like defects to the Raman spectra of graphene-related materials embracing, from the topology point of view, all possible structures from perfect to fully disordered sp2 bonded carbons. Two sets of graphene-related samples, produced by well-established protocols that generate either 0D or 1D defects in a controlled way, are analysed with our model and used to parameterize the limiting values of the phase space. We then discuss the limitations and apply our new methodology to analyse the structure of two-dimensional nanocarbons generated from renewable gas, used to produce inks and conducting coatings.
170 citations
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Santa Fe Institute1, University of Arizona2, Missouri Botanical Garden3, Conservation International4, New York Botanical Garden5, Xishuangbanna Tropical Botanical Garden6, University of Montpellier7, South African National Parks8, Royal Botanic Gardens9, University of Leeds10, Pontifical Catholic University of Chile11, University of Connecticut12, Stellenbosch University13, University of Copenhagen14, Universidade Federal de Minas Gerais15, University of California, Los Angeles16, Harvard University17, University of North Carolina at Chapel Hill18, University of Lorraine19, Santa Clara University20, University of California, Santa Barbara21, Charles University in Prague22, Paul Valéry University, Montpellier III23, Naturalis24, Landcare Research25, Aarhus University26, University of Maine27
TL;DR: The results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth’s plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species.
Abstract: A key feature of life’s diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant diversity to quantify the fraction of Earth’s plant biodiversity that are rare. A large fraction, ~36.5% of Earth’s ~435,000 plant species, are exceedingly rare. Sampling biases and prominent models, such as neutral theory and the k-niche model, cannot account for the observed prevalence of rarity. Our results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth’s plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species. Estimates of global species abundance distributions have important implications for risk assessments and conservation planning in this era of rapid global change.
170 citations
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TL;DR: The (12,0) imogolite tube has the highest stability of all tubes studied here, and an analysis of the electronic densities of states shows that all imoglite tubes, independent on their chirality and size, are insulators.
Abstract: The aluminosilicate mineral imogolite is composed of single-walled nanotubes with stoichiometry of (HO)(3)Al(2)O(3)SiOH and occurs naturally in soils of volcanic origin. In the present work we study the stability and the electronic and mechanical properties of zigzag and armchair imogolite nanotubes using the density-functional tight-binding method. The (12,0) imogolite tube has the highest stability of all tubes studied here. Uniquely for nanotubes, imogolite has a minimum in the strain energy for the optimum structure. This is in agreement with experimental data, as shown by comparison with the simulated X-ray diffraction spectrum. An analysis of the electronic densities of states shows that all imogolite tubes, independent on their chirality and size, are insulators.
169 citations
Authors
Showing all 42077 results
Name | H-index | Papers | Citations |
---|---|---|---|
Michael Marmot | 193 | 1147 | 170338 |
Pulickel M. Ajayan | 176 | 1223 | 136241 |
Alan D. Lopez | 172 | 863 | 259291 |
Jens Nielsen | 149 | 1752 | 104005 |
Mildred S. Dresselhaus | 136 | 762 | 112525 |
Jing Kong | 126 | 553 | 72354 |
Mauricio Terrones | 118 | 760 | 61202 |
Michael Brammer | 118 | 424 | 46763 |
Terence G. Langdon | 117 | 1158 | 61603 |
Caroline A. Sabin | 108 | 690 | 44233 |
Michael Brauer | 106 | 480 | 73664 |
Michael Bader | 103 | 735 | 37525 |
Michael S. Strano | 98 | 480 | 60141 |
Pablo Jarillo-Herrero | 91 | 245 | 39171 |
Riichiro Saito | 91 | 502 | 48869 |