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 & Context (language use). The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.
Topics: Population, Context (language use), Medicine, Immune system, Health care
Papers published on a yearly basis
Papers
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TL;DR: A RRS study of samples of WSe2 with one, two, and three layers, as well as bulk 2H-WSe2, using up to 20 different laser lines covering the visible range shows that Raman enhancement is much stronger for the excited A' and B' states.
Abstract: Resonant Raman spectroscopy (RRS) is a very useful tool to study physical properties of materials since it provides information about excitons and their coupling with phonons. We present in this work a RRS study of samples of WSe2 with one, two, and three layers (1L, 2L, and 3L), as well as bulk 2H-WSe2, using up to 20 different laser lines covering the visible range. The first- and second-order Raman features exhibit different resonant behavior, in agreement with the double (and triple) resonance mechanism(s). From the laser energy dependence of the Raman intensities (Raman excitation profile, or REP), we obtained the energies of the excited excitonic states and their dependence with the number of atomic layers. Our results show that Raman enhancement is much stronger for the excited A' and B' states, and this result is ascribed to the different exciton-phonon coupling with fundamental and excited excitonic states.
208 citations
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TL;DR: In this paper, the structure and properties of bismuth nanowires and carbon nanotubes are discussed and compared with those of carbon nanostructures and nanoscience concepts.
207 citations
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University of São Paulo1, Rio de Janeiro State University2, Universidade Federal de Goiás3, Universidade Federal do Rio Grande do Sul4, Universidade Federal de Minas Gerais5, Federal University of São Paulo6, Federal Fluminense University7, Pontifícia Universidade Católica de Campinas8, Federal University of Maranhão9, Pontifícia Universidade Católica do Paraná10, Universidade Luterana do Brasil11, Pontifícia Universidade Católica do Rio Grande do Sul12, Universidade Estadual de Londrina13, Federal University of Rio de Janeiro14, Universidade Federal do Acre15
TL;DR: Parte 1: Diretriz Brasileira de Insuficiencia Cardiaca Cronica Cronica e Aguda.
Abstract: Parte 1: Diretriz Brasileira de Insuficiencia Cardiaca Cronica […] Diretriz Brasileira de Insuficiencia Cardiaca Cronica e Aguda
207 citations
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TL;DR: The objective of this systematic review was to identify determinants of health care‐seeking in studies with well‐defined groups of care‐seekers and non‐seekers with non‐specific low back pain.
207 citations
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19 May 2012
TL;DR: In this paper, it was shown that for any constant even integer q ≥ 4, a graph G is a small-set expander if and only if the projector into the span of the top eigenvectors of G's adjacency matrix has bounded 2-q norm.
Abstract: We study the computational complexity of approximating the 2-to-q norm of linear operators (defined as |A|2->q = maxv≠ 0|Av|q/|v|2) for q > 2, as well as connections between this question and issues arising in quantum information theory and the study of Khot's Unique Games Conjecture (UGC). We show the following: For any constant even integer q ≥ 4, a graph G is a small-set expander if and only if the projector into the span of the top eigenvectors of G's adjacency matrix has bounded 2->q norm. As a corollary, a good approximation to the 2->q norm will refute the Small-Set Expansion Conjecture --- a close variant of the UGC. We also show that such a good approximation can be obtained in exp(n2/q) time, thus obtaining a different proof of the known subexponential algorithm for Small-Set-Expansion. Constant rounds of the "Sum of Squares" semidefinite programing hierarchy certify an upper bound on the 2->4 norm of the projector to low degree polynomials over the Boolean cube, as well certify the unsatisfiability of the "noisy cube" and "short code" based instances of Unique-Games considered by prior works. This improves on the previous upper bound of exp(logO(1) n) rounds (for the "short code"), as well as separates the "Sum of Squares"/"Lasserre" hierarchy from weaker hierarchies that were known to require ω(1) rounds. We show reductions between computing the 2->4 norm and computing the injective tensor norm of a tensor, a problem with connections to quantum information theory. Three corollaries are: (i) the 2->4 norm is NP-hard to approximate to precision inverse-polynomial in the dimension, (ii) the 2->4 norm does not have a good approximation (in the sense above) unless 3-SAT can be solved in time exp(√n poly log(n)), and (iii) known algorithms for the quantum separability problem imply a non-trivial additive approximation for the 2->4 norm.
207 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 |