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‣ Distribution of human immunodeficiency virus type 1 subtypes in the State of Amazonas, Brazil, and subtype C identification

Cunha, L. K. H.; Kashima, S.; Amarante, M. F. C.; Haddad, R.; Rodrigues, E. S.; Silva, K. L. T.; Lima, T. A.; Castro, D. B.; Brito, F. C.; Almeida, E. G.; Covas, D. T.; Malheiro, A.
Fonte: ASSOC BRAS DIVULG CIENTIFICA; SAO PAULO Publicador: ASSOC BRAS DIVULG CIENTIFICA; SAO PAULO
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.50309%
Few studies have reported the molecular epidemiological characterization of HIV-1 in the Northern region of Brazil. The present study reports the molecular and epidemiological characterization of 31 HIV-1 isolates from blood donors from the State of Amazonas who donated blood between April 2006 and March 2007. Serum/plasma samples from all donors were screened for HIV antibodies by ELISA and the results confirmed by Western blot analysis. Genomic DNA was extracted from the buffy coat using the Super Quik-Gene-DNA Isolation kit. Nested PCR was performed on the env, gag, and pol regions of HIV-1 using the Gene Amp PCR System 9700. Sequencing reactions were performed using the inner PCR primers and the DYEnamic (TM) ET Dye Terminator Kit, and phylogenetic analysis was performed using the gag, pol, and env gene sequences. We collected samples from 31 blood donors who tested positive for HIV-1 in confirmatory experiments. The male: female ratio of blood donors was 3.4:1, and the mean age was 32.4 years (range: 19 to 61 years). Phylogenetic analysis showed that subtype B is the most prevalent among Northern Brazilian HIV-1-seropositive blood donors. One HIV-1 subtype C and one circulating recombinant form (CRF_BF) of HIV-1 were identified in the State of Amazonas. This is the first study showing the occurrence of a possible "homogenous" subtype C in this region of Brazil. This finding could contribute to a better characterization of the HIV-1 strains that circulate in the country.; CNPq; CNPq; Fundacao de Amparo a Pesquisa do Estado do Amazonas; Fundacao de Amparo a Pesquisa do Estado do Amazonas; Center for Cell-Therapy (CTC)/Fundacao Hemocentro de Ribeirao Preto; Center for CellTherapy (CTC)/Fundacao Hemocentro de Ribeirao Preto; FAPESP; FAPESP

‣ Distribution of human immunodeficiency virus type 1 subtypes in the state of Amazonas, Brazil, and subtype C identification

Cunha, L.K.H.; Kashima, S.; Amarante, M.F.C.; Haddad, R.; Rodrigues, E.S.; Silva, K.L.T.; Lima, T.A.; Castro, D.B.; Brito, F.C.; Almeida, E.G.; Covas, D.T.; Malheiro, A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.49893%
Few studies have reported the molecular epidemiological characterization of HIV-1 in the Northern region of Brazil. The present study reports the molecular and epidemiological characterization of 31 HIV-1 isolates from blood donors from the State of Amazonas who donated blood between April 2006 and March 2007. Serum/plasma samples from all donors were screened for HIV antibodies by ELISA and the results confirmed by Western blot analysis. Genomic DNA was extracted from the buffy coat using the Super Quik-Gene-DNA Isolation kit. Nested PCR was performed on the env, gag, and pol regions of HIV-1 using the Gene Amp PCR System 9700. Sequencing reactions were performed using the inner PCR primers and the DYEnamic™ ET Dye Terminator Kit, and phylogenetic analysis was performed using the gag, pol, and env gene sequences. We collected samples from 31 blood donors who tested positive for HIV-1 in confirmatory experiments. The male:female ratio of blood donors was 3.4:1, and the mean age was 32.4 years (range: 19 to 61 years). Phylogenetic analysis showed that subtype B is the most prevalent among Northern Brazilian HIV-1-seropositive blood donors. One HIV-1 subtype C and one circulating recombinant form (CRF_BF) of HIV-1 were identified in the State of Amazonas. This is the first study showing the occurrence of a possible "homogenous" subtype C in this region of Brazil. This finding could contribute to a better characterization of the HIV-1 strains that circulate in the country.

‣ Atmospheric electrical field suppression in the time of the M =4.1 Sousel earthquake (Portugal)

Silva, Hugo Gonçalves; Serrano, C.; Reis, A.H.; Bezzeghoud, Mourad; Rosa, R.N.; Borges, J.F.; Caldeira, B.; Tlemçani, M.
Fonte: Electrostatics 2011 - IOP Conferences Publicador: Electrostatics 2011 - IOP Conferences
Tipo: Aula
Português
Relevância na Pesquisa
56.55218%
In recent years different phenomena associated with seismic events have been referred in the literature. These include: unusual ultra-low-frequency electromagnetic emissions [1]; anomalies in very-low and low-frequencies radio transmissions [2]; variation of the ionosphere total electron content [3]; and anomalous levels of different geochemical elements (in particular radon) in the earthquake preparation zone have been reported [4]. Interestingly, an innovative paper has shown the possibility of enhanced air ionization, with consequent atmospheric electricity perturbations, in the preparatory stage of seismic events [5]. It relates possible atmospheric electrical field anomalies during the earthquake preparation with surface air ionization through radon emanations. In fact, this work presents the observation of a significant suppression of the vertical component of the atmospheric electrical field that occurred in Évora (Portugal) soon before the M = 4.1 Sousel earthquake of 27 March 2010. The observation is reported, followed by the analysis and interpretation. Preliminary conclusions and plans for future works are drawn. References [1] T. Bleier et al., Nat. Hazards Earth Syst. Sci. 9, 585, 2009. [2] P.F. Biagi, et al., Nat. Hazards Earth Syst. Sci. 9...

‣ Microalbuminúria em pacientes diabéticos tipo 1: prevalência e fatores associados

Piccirillo,Laura J.; Cunha,Edna F.; Gonçalves,Maria de F.R.; Clemente,Eliete L.S.; Neves,Ricardo; Gomes,Marília de B.
Fonte: Sociedade Brasileira de Endocrinologia e Metabologia Publicador: Sociedade Brasileira de Endocrinologia e Metabologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2002 Português
Relevância na Pesquisa
56.49893%
Para avaliar a freqüência da microalbuminúria e fatores clínicos e metabólicos associados, estudamos 72 pacientes com diabetes tipo 1 [DM1, 38F/34M, sendo 6 crianças, 17 adolescentes e 49 adultos, com 22,7±9,5 anos e 7 anos (0,1-37,5) de duração da doença]. A taxa de excreção de albumina (EUA) foi determinada em amostra noturna de urina de 10h. Microalbuminúria foi definida como EUA > ou = 20 e <200mig/min em pelo menos 2 de 3 amostras de urina, 25% mostraram-se microalbuminúricos (16 adultos e 2 adolescentes) e tinham maiores médias de idade (27,3±5,8 vs 20,9±10,1 anos, p<0,001), duração do DM [11,0 (0,1-17,0) vs 5,9 (1,0-37,5) anos, p<0,05], índice de massa corporal (22,7±2,6 vs 20,7±3,1, p<0,05), uréia (32,4±7,8 vs 28,3±5,9mg/dl, p<0,05), creatinina [0,7 (0,6-1,2) vs 0,6 (0,4-1,1) mg/dl, p<0,05] e maior freqüência de retinopatia (33% vs 9,4%, p<0,05) quando comparados aos normoalbuminúricos. Na regressão linear múltipla em stepwise, tendo a EUA como variável dependente, a única variável independente associada e preditora foi a idade (r²= 0,13, p<0,05). Concluímos que a idade foi um fator determinante no surgimento da microalbuminúria. Apesar de não termos observado microalbuminúria em crianças sugerimos que a triagem nesta faixa etária deve ser discutida no contexto específico de cada serviço de atendimento ao diabetes.

‣ Anxiolytic-like effects of 4-phenyl-2-trichloromethyl-3H-1,5-benzodiazepine hydrogen sulfate in mice

Rubin,M.A.; Albach,C.A.; Berlese,D.B.; Bonacorso,H.G.; Bittencourt,S.R.T.; Queiroz,C.M.T.; Maixner,A.E.; Mello,C.F.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2000 Português
Relevância na Pesquisa
56.77408%
The pharmacological effects of 4-phenyl-2-trichloromethyl-3H-1,5-benzodiazepine hydrogen sulfate (PTMB), a novel synthetic benzodiazepine, were examined in mice. In the elevated plus-maze test of anxiety, 0.3-1 mg/kg diazepam ip (F(3,53) = 3.78; P<0.05) and 1-10 mg/kg PTMB ip increased (F(5,98) = 3.26; P<0.01), whereas 2 mg/kg picrotoxin ip decreased (F(3,59) = 8.32; P<0.001) the proportion of time spent in the open arms, consistent with an anxiolytic action of both benzodiazepines, and an anxiogenic role for picrotoxin. In the holeboard, 1.0 mg/kg diazepam ip increased (F(3,54) = 2.78; P<0.05) and 2 mg/kg picrotoxin ip decreased (F(3,59) = 4.69; P<0.01) locomotor activity. Rotarod assessment revealed that 1 mg/kg diazepam ip and 3, 10 and 30 mg/kg PTMB ip produced significant motor incoordination compared to vehicle control (F(4,70) = 7.6; P<0.001). These data suggest that the recently synthesized PTMB compound possesses anxiolytic activity and produces motor incoordination similar to those observed with diazepam.

‣ Distribution of human immunodeficiency virus type 1 subtypes in the state of Amazonas, Brazil, and subtype C identification

Cunha,L.K.H.; Kashima,S.; Amarante,M.F.C.; Haddad,R.; Rodrigues,E.S.; Silva,K.L.T.; Lima,T.A.; Castro,D.B.; Brito,F.C.; Almeida,E.G.; Covas,D.T.; Malheiro,A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2012 Português
Relevância na Pesquisa
56.49893%
Few studies have reported the molecular epidemiological characterization of HIV-1 in the Northern region of Brazil. The present study reports the molecular and epidemiological characterization of 31 HIV-1 isolates from blood donors from the State of Amazonas who donated blood between April 2006 and March 2007. Serum/plasma samples from all donors were screened for HIV antibodies by ELISA and the results confirmed by Western blot analysis. Genomic DNA was extracted from the buffy coat using the Super Quik-Gene-DNA Isolation kit. Nested PCR was performed on the env, gag, and pol regions of HIV-1 using the Gene Amp PCR System 9700. Sequencing reactions were performed using the inner PCR primers and the DYEnamic™ ET Dye Terminator Kit, and phylogenetic analysis was performed using the gag, pol, and env gene sequences. We collected samples from 31 blood donors who tested positive for HIV-1 in confirmatory experiments. The male:female ratio of blood donors was 3.4:1, and the mean age was 32.4 years (range: 19 to 61 years). Phylogenetic analysis showed that subtype B is the most prevalent among Northern Brazilian HIV-1-seropositive blood donors. One HIV-1 subtype C and one circulating recombinant form (CRF_BF) of HIV-1 were identified in the State of Amazonas. This is the first study showing the occurrence of a possible "homogenous" subtype C in this region of Brazil. This finding could contribute to a better characterization of the HIV-1 strains that circulate in the country.

‣ Homozygous 4.1(-) hereditary elliptocytosis associated with a point mutation in the downstream initiation codon of protein 4.1 gene.

Dalla Venezia, N; Gilsanz, F; Alloisio, N; Ducluzeau, M T; Benz, E J; Delaunay, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1992 Português
Relevância na Pesquisa
56.5162%
We studied a 43 yr-old Spanish patient with homozygous 4.1(-) hereditary elliptocytosis. Any form of protein 4.1 was missing in the red cells. Spectrin and actin were slightly, yet significantly, diminished. Alterations appeared at the level of proteins 4.5 and 4.9. Glycophorin C was sharply reduced. The abnormal allele was associated with the -++-- haplotype (Pvu II, Bgl II, Bgl II, Pvu II, Pvu II). mRNA 4.1(-) had an apparently normal size but was diminished by about two-thirds. Because the abnormal phenotype pertained to the red cell, we sequenced the 4.1 cDNA regions that appear critical to this cell type. The ultimate change turned out to be a point mutation of the downstream translation initiation codon (AUG-->AGG). No disorders in other cell types could be related with certainty to the present 4.1(-) HE allele.

‣ The 4.1/ezrin/radixin/moesin domain of the DAL-1/Protein 4.1B tumour suppressor interacts with 14-3-3 proteins.

Yu, Tingxi; Robb, Victoria A; Singh, Vinita; Gutmann, David H; Newsham, Irene F
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/08/2002 Português
Relevância na Pesquisa
56.57517%
The Protein 4.1 family contains at least two members that function as tumour suppressors, the neurofibromatosis 2 gene product merlin and the recently identified differentially expressed in adenocarcinoma of the lung (DAL-1)/Protein 4.1B molecule. DAL-1/Protein 4.1B loss is observed in a variety of tumours, including breast and lung cancers as well as meningiomas. We have previously demonstrated that DAL-1/Protein 4.1B interacts with some but not all merlin-binding proteins, raising the possibility that DAL-1/Protein 4.1B associates with additional unique proteins specific to its function as a negative growth regulator. Using yeast two-hybrid interaction cloning, we identified three 14-3-3 isoforms, beta, gamma and eta, to be DAL-1/Protein 4.1B-binding proteins. These interactions were verified by using glutathione S-transferase affinity chromatography in vitro and co-immunoprecipitation in vivo. The interaction of 14-3-3 with DAL-1/Protein 4.1B was specific, as 14-3-3 did not bind to the related Protein 4.1 family members merlin, ezrin or radixin. The DAL-1/Protein 4.1B domain that mediates 14-3-3 binding was mapped to residues Pro(244) and Leu(280) within the 4.1/ezrin/radixin/moesin domain. The identification of this novel DAL-1/Protein 4.1B-interacting protein represents the first step towards elucidating its potentially unique mechanism of action.

‣ Interactions of thrombospondins with α4β1 integrin and CD47 differentially modulate T cell behavior

Li, Zhuqing; Calzada, Maria J.; Sipes, John M.; Cashel, Jo Anne; Krutzsch, Henry C.; Annis, Douglas S.; Mosher, Deane F.; Roberts, David D.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 29/04/2002 Português
Relevância na Pesquisa
56.496064%
Thrombospondin (TSP)-1 has been reported to modulate T cell behavior both positively and negatively. We found that these opposing responses arise from interactions of TSP1 with two different T cell receptors. The integrin α4β1 recognizes an LDVP sequence in the NH2-terminal domain of TSP1 and was required for stimulation of T cell adhesion, chemotaxis, and matrix metalloproteinase gene expression by TSP1. Recognition of TSP1 by T cells depended on the activation state of α4β1 integrin, and TSP1 inhibited interaction of activated α4β1 integrin on T cells with its counter receptor vascular cell adhesion molecule-1. The α4β1 integrin recognition site is conserved in TSP2. A recombinant piece of TSP2 containing this sequence replicated the α4β1 integrin–dependent activities of TSP1. The β1 integrin recognition sites in TSP1, however, were neither necessary nor sufficient for inhibition of T cell proliferation and T cell antigen receptor signaling by TSP1. A second TSP1 receptor, CD47, was not required for some stimulatory responses to TSP1 but played a significant role in its T cell antigen receptor antagonist and antiproliferative activities. Modulating the relative expression or function of these two TSP receptors could therefore alter the direction or magnitude of T cell responses to TSPs.

‣ Expression of functionally active α4β1 integrin by thymic epithelial cells

NIETO, M; GÓMEZ, M; SÁNCHEZ-MATEOS, P; FERNÁNDEZ, E; MARAZUELA, M; SACEDÓN, R; VARAS, A; GONZÁLEZ-AMARO, R; ZAPATA, A G; TORIBIO, M L; SÁNCHEZ-MADRID, F
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /10/1996 Português
Relevância na Pesquisa
56.54065%
We have investigated the expression and function of the VLA-4 heterodimer α4β1, a member of the β1 integrin subfamily, on human thymic epithelial cells (TEC) derived from cortical epithelium. The expression of the α4 integrin chain was studied in four different cloned TEC lines derived from either fetal or post-natal human thymus by both flow cytometry and immunoprecipitation techniques with anti-α4 MoAbs. All different cell lines assayed expressed significant levels of α4, as revealed by their reactivity with MoAbs specific for distinct α4epitopes. The α4 subunit expressed by TEC was associated to β1 but not to β7 chain, and displayed the characteristic 80/70 kD pattern of proteolytic cleavage. The VLA-4 integrin in these cells was constitutively active in terms of adhesiveness to both fibronectin and vascular cell adhesion molecule-1 (VCAM-1). In addition, this heterodimer localized to punctate regions of the cell in the area of contact with the substratum, named point contacts assessed by staining with the anti-β1 activation epitope 15/7 MoAb. According to the cortical origin of the TEC lines expressing VLA-4, human thymus sections stained with different anti-α4 antibodies revealed the presence of cortical, and in smaller numbers medullary epithelial cells bearing α4 integrin. The expression of α4 in the thymus was also found in both adult and fetal rats...

‣ Protein 4.1 deficiency associated with an altered binding to the spectrin-actin complex of the red cell membrane skeleton.

Lorenzo, F; Dalla Venezia, N; Morlé, L; Baklouti, F; Alloisio, N; Ducluzeau, M T; Roda, L; Lefrançois, P; Delaunay, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1994 Português
Relevância na Pesquisa
56.57963%
Protein 4.1 has been defined as a major component of the subcortical skeleton of erythrocytes. It binds the spectrin--actin scaffold through a 10-kD internal domain. This binding requires an essential 21-amino acid sequence motif, Motif I, which is retained by alternative splicing at the late stage of erythroid differentiation. We here analyze the molecular basis of heterozygous 4.1(-) hereditary elliptocytosis, associated with protein 4.1 partial deficiency, in nine related French families. cDNA sequencing revealed a single codon deletion (AAA) resulting in a lysine residue deletion within the 10-kD binding domain, 3' of Motif I. The mutated allele was designated allele 4.1 Aravis. In order to assess the functional effect of the codon deletion, recombinant 10-kD constructs were made and various binding assays were performed using spectrin, purified spectrin-actin complex, or red cell membranes. These experiments demonstrated that the deletion of the Lys residue clearly prevents the binding capacity. Similar results were obtained with a construct containing the Lys residue but lacking Motif I. These data strongly suggest that the binding site to the spectrin-actin complex must contain the Lys 447 (or 448), and therefore resides not only on Motif I but extends 3' of this essential motif.

‣ Linear competitive inhibition of human tissue kallikrein by 4-aminobenzamidine and benzamidine and linear mixed inhibition by 4-nitroaniline and aniline

Sousa,M.O.; Miranda,T.L.S.; Costa,E.B.; Bittar,E.R.; Santoro,M.M.; Figueiredo,A.F.S.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2001 Português
Relevância na Pesquisa
56.501206%
Hydrolysis of D-valyl-L-leucyl-L-arginine p-nitroanilide (7.5-90.0 µM) by human tissue kallikrein (hK1) (4.58-5.27 nM) at pH 9.0 and 37ºC was studied in the absence and in the presence of increasing concentrations of 4-aminobenzamidine (96-576 µM), benzamidine (1.27-7.62 mM), 4-nitroaniline (16.5-66 µM) and aniline (20-50 mM). The kinetic parameters determined in the absence of inhibitors were: Km = 12.0 ± 0.8 µM and k cat = 48.4 ± 1.0 min-1. The data indicate that the inhibition of hK1 by 4-aminobenzamidine and benzamidine is linear competitive, while the inhibition by 4-nitroaniline and aniline is linear mixed, with the inhibitor being able to bind both to the free enzyme with a dissociation constant Ki yielding an EI complex, and to the ES complex with a dissociation constant Ki', yielding an ESI complex. The calculated Ki values for 4-aminobenzamidine, benzamidine, 4-nitroaniline and aniline were 146 ± 10, 1,098 ± 91, 38.6 ± 5.2 and 37,340 ± 5,400 µM, respectively. The calculated Ki' values for 4-nitroaniline and aniline were 289.3 ± 92.8 and 310,500 ± 38,600 µM, respectively. The fact that Ki'>Ki indicates that 4-nitroaniline and aniline bind to a second binding site in the enzyme with lower affinity than they bind to the active site. The data about the inhibition of hK1 by 4-aminobenzamidine and benzamidine help to explain previous observations that esters...

‣ Vertex operator algebra analogue of embedding of $B_4$ into $F_4$

Perse, Ozren
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.64642%
Let L_{B}(-5/2,0) (resp. L_{F}(-5/2,0)) be the simple vertex operator algebra associated to affine Lie algebra of type $B_{4}^{(1)}$ (resp. $F_{4}^{(1)}$) with the lowest admissible half-integer level -5/2. We show that L_{B}(-5/2,0) is a vertex subalgebra of L_{F}(-5/2,0) with the same conformal vector, and that L_{F}(-5/2,0) is isomorphic to the extension of L_{B}(-5/2,0) by its only irreducible module other than itself. We also study the representation theory of L_{F}(-5/2,0), and determine the decompositions of irreducible weak L_{F}(-5/2,0)-modules from the category $\mathcal{O}$ into direct sums of irreducible weak L_{B}(-5/2,0)-modules.; Comment: 31 pages, LaTeX; revised version

‣ Reducing multi-qubit interactions in adiabatic quantum computation without adding auxiliary qubits. Part 1: The "deduc-reduc" method and its application to quantum factorization of numbers

Tanburn, Richard; Okada, Emile; Dattani, Nike
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.728965%
Adiabatic quantum computing has recently been used to factor 56153 [Dattani & Bryans, arXiv:1411.6758] at room temperature, which is orders of magnitude larger than any number attempted yet using Shor's algorithm (circuit-based quantum computation). However, this number is still vastly smaller than RSA-768 which is the largest number factored thus far on a classical computer. We address a major issue arising in the scaling of adiabatic quantum factorization to much larger numbers. Namely, the existence of many 4-qubit, 3-qubit and 2-qubit interactions in the Hamiltonians. We showcase our method on various examples, one of which shows that we can remove 94% of the 4-qubit interactions and 83% of the 3-qubit interactions in the factorization of a 25-digit number with almost no effort, without adding any auxiliary qubits. Our method is not limited to quantum factoring. Its importance extends to the wider field of discrete optimization. Any CSP (constraint-satisfiability problem), psuedo-boolean optimization problem, or QUBO (quadratic unconstrained Boolean optimization) problem can in principle benefit from the "deduction-reduction" method which we introduce in this paper. We provide an open source code which takes in a Hamiltonian (or a discrete discrete function which needs to be optimized)...

‣ Branching Rule Decomposition of Irreducible Level-1 E_6^(1)-modules with respect to F_4^(1)

Mauriello, Chris
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/07/2013 Português
Relevância na Pesquisa
66.66377%
It is well known that using the weight lattice of type $E_6$, $P$, and the lattice construction for vertex operator algebras one can obtain all three level 1 irreducible $\tilde{g}$-modules with $V_P = V^{\Lamba_0} \oplus V^{\Lamba_1} \oplus V^{\Lamba_6}$. The Dynkin diagram of type $E_6$ has an order 2 automorphism, $\tau$, which can be lifted to $\tilde{{\tau}}$, a Lie algebra automorphism of $\tilde{g}$ of type $E_6^(1)$. The fixed points of $\tilde{{\tau}}$ are a subalgebra $\tilde{a}$ of type $F_4^(1)$. The automorphism $\tau$ lifts further to $\hat{{\tau}}$ a vertex operator algebra automorphism of $V_P$. We investigate the branching rules, how these three modules for the affine Lie algebra $\tilde{g}$ decompose as a direct sum of irreducible $\tilde{a}$-modules. To complete the decomposition we use the Godard-Kent-Olive coset construction which gives a $c = \frac{4}{5}$ module for the Virasoro algebra on $V_P$ which commutes with $\tilde{a}$. We use the irreducible modules for this coset Virasoro to give the space of highest weight vectors for $\tilde{a}$ in each $V^{\Lamba_i}$. The character theory related to this decomposition is examined and we make a connection to one of the famous Ramanujan identities. This dissertation constructs coset Virasoro operators $Y(\omg...

‣ Extended F_4-buildings and the Baby Monster

Ivanov, A. A.; Pasechnik, D. V.; Shpectorov, S. V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/12/2000 Português
Relevância na Pesquisa
56.7529%
The Baby Monster group B acts naturally on a geometry E(B) with diagram c.F_4(t) for t=4 and the action of B on E(B) is flag-transitive. It possesses the following properties: (a) any two elements of type 1 are incident to at most one common element of type 2, and (b) three elements of type 1 are pairwise incident to common elements of type 2 iff they are incident to a common element of type 5. It is shown that E(B) is the only (non-necessary flag-transitive) c.F_4(t)-geometry, satisfying t=4, (a) and (b), thus obtaining the first characterization of B in terms of an incidence geometry, similar in vein to one known for classical groups acting on buildings. Further, it is shown that E(B) contains subgeometries E(^2E_6(2)) and E(Fi22) with diagrams c.F_4(2) and c.F_4(1). The stabilizers of these subgeometries induce on them flag-transitive actions of ^2E_6(2):2 and Fi22:2, respectively. Three further examples for t=2 with flag-transitive automorphism groups are constructed. A complete list of possibilities for the isomorphism type of the subgraph induced by the common neighbours of a pair of vertices at distance 2 in an arbitrary c.F_4(t) satisfying (a) and (b) is obtained.; Comment: to appear in Inventiones Mathematicae

‣ A $N_f = 2 + 1 + 1$ "twisted" determination of the $b$-quark mass, $f_{B}$ and $f_{B_s}$

Carrasco, N.; Dimopoulos, P.; Frezzotti, R.; Giménez, V.; Lami, P.; Lubicz, V.; Picca, E.; Riggio, L.; Rossi, G. C.; Sanfilippo, F.; Simula, S.; Tarantino, C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/11/2013 Português
Relevância na Pesquisa
56.616304%
We present a lattice QCD determination of the $b$-quark mass and of the $f_{B_s}$ and $f_B$ decay constants performed with $N_f = 2 + 1 + 1$ twisted mass Wilson fermions. We have used simulations at three values of the lattice spacing generated by ETMC with pion masses ranging from 210 to 440 MeV. To obtain physical quantities we performed a combined chiral and continuum limit and an extrapolation in the heavy quark mass from the charm to the $b$-quark region using suitable ratios calculated at nearby heavy-quark masses having an exactly known static limit. Our results are: $m_b(m_b) = 4.29 (13)$ GeV, $f_B = 196 (9)$ MeV, $f_{B_s} = 235 (9)$ MeV, $f_{B_s} / f_B = 1.201 (25)$, $(f_{B_s}/f_B)/(f_K/f_\pi) = 1.007 (16)$ and $(f_{B_s}/f_B)/(f_{D_s}/f_D) = 1.008 (13)$.; Comment: 7 pages, 7 figures, presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany

‣ Pseudoscalar decay constants $f_K/f_\pi$, $f_D$ and $f_{D_s}$ with $N_f = 2 + 1 + 1$ ETMC configurations

Dimopoulos, P.; Frezzotti, R.; Lami, P.; Lubicz, V.; Picca, E.; Riggio, L.; Rossi, G. C.; Sanfilippo, F.; Simula, S.; Tarantino, C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/11/2013 Português
Relevância na Pesquisa
56.6369%
We present a lattice QCD calculation of the pseudoscalar decay constants $f_K$, $f_D$ and $f_{D_s}$ performed by the European Twisted Mass Collaboration with $N_f = 2 + 1 + 1$ dynamical fermions. We simulated at three different values of the lattice spacing, the smallest being approximately $0.06fm$, and with pion masses as small as $210$MeV. Our main results are: $f_{K^+}/f_{\pi^+}=1.183(17)$, $f_{K^+}=154.4(2.1)$MeV, $f_{D_s}=242.1(8.3)$MeV, $f_D=201.9(8.0)$MeV, $f_{D_s}/f_D=1.199(25)$ and $(f_{D_s}/f_D) / (f_K/f_\pi) = 1.005(15)$.; Comment: 7 pages, 5 figures, presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany

‣ Quantum factorization of 56153 with only 4 qubits

Dattani, Nikesh S.; Bryans, Nathaniel
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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The largest number factored on a quantum device reported until now was 143. That quantum computation, which used only 4 qubits at 300K, actually also factored much larger numbers such as 3599, 11663, and 56153, without the awareness of the authors of that work. Furthermore, unlike the implementations of Shor's algorithm performed thus far, these 4-qubit factorizations do not need to use prior knowledge of the answer. However, because they only use 4 qubits, these factorizations can also be performed trivially on classical computers. We discover a class of numbers for which the power of quantum information actually comes into play. We then demonstrate a 3-qubit factorization of 175, which would be the first quantum factorization of a triprime.; Comment: Replaced 44929 with larger number (56153) that results in same Hamiltonian as 143, edited corresponding table and equations. Similarly replaced 13081 with 11663. Fixed typo in equations 14, 15, 19-21

‣ RI/MOM renormalization constants (N_f=4) and the strong coupling constant (N_f=2+1+1) from twisted-mass QCD

Blossier, B.; Boucaud, Ph.; Brinet, M.; De Soto, F.; Du, X.; Gravina, M.; Liu, Z.; Morenas, V.; Pène, O.; Petrov, K.; Rodríguez-Quintero, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/11/2011 Português
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We study RI/MOM renormalization constants of bilinear quark operators for $N_f=4$ and the strong coupling constant for $N_f=2+1+1$ using Wilson twisted-mass fermions. We use the "egalitarian" method to remove H(4) hypercubic artifacts non-perturbatively, which enables us to study physical quantities in a wide range of momenta. We then apply OPE in studying the running behavior of $Z_q$ and $\alpha_s$, from which we are able to extract the Landau gauge dimension-two gluon condensate $$ which is of phenomenological interest.; Comment: 7 pages, talk presented at The XXIX International Symposium on Lattice Field Theory - Lattice 2011, July 10-16, 2011, Squaw Valley, Lake Tahoe, California