368 research outputs found
Optical Bell-state analysis in the coincidence basis
Many quantum information protocols require a Bell-state measurement of
entangled systems. Most optical Bell-state measurements utilize two-photon
interference at a beam splitter. By creating polarization-entangled photons
with spontaneous parametric down-conversion using a first-order
Hermite-Gaussian pump beam, we invert the usual interference behavior and
perform an incomplete Bell-state measurement in the coincidence basis. We
discuss the possibility of a complete Bell-state measurement in the coincidence
basis using hyperentangled states [Phys. Rev. A, \textbf{58}, R2623 (1998)].Comment: 5 pages, 5 figure
Interference and complementarity for two-photon hybrid entangled states
In this work we generate two-photon hybrid entangled states (HES), where the
polarization of one photon is entangled with the transverse spatial degree of
freedom of the second photon. The photon pair is created by parametric
down-conversion in a polarization-entangled state. A birefringent double-slit
couples the polarization and spatial degrees of freedom of these photons and
finally, suitable spatial and polarization projections generate the HES. We
investigate some interesting aspects of the two-photon hybrid interference, and
present this study in the context of the complementarity relation that exists
between the visibilities of the one- and two-photon interference patterns.Comment: 10 pages, 4 figures. Accepted in Physical Review
Efeito do pH da água no equilíbrio iônico de alevinos de Piaractus mesopotamicus.
Este trabalho teve objetivo de testar o equilíbrio iônico de alevinos de pacu (Piaractus mesopotamicus) em ambientes de pH ácido, neutro e alcalino
Natural polymorphisms of HIV type 2 pol sequences from drug-naive individuals
Until today, the susceptibility of human immunodeficiency virus type 2 (HIV-2) to protease and nucleosidic reverse-transcriptase inhibitors (PI and NRTI, respectively) has not been clearly documented. In this report we studied HIV-2 proviral sequences (n = 30) from drug-naive patients. Our results revealed that several amino acid positions in the protease and reverse transcriptase coding sequence harbored residues that have been associated with drug resistance in HIV-1-infected patients. In particular, the M46I substitution in the protease was detected in 90% of the sequences analyzed, which, together with the other substitutions identified, may indicate a reduced susceptibility of HIV-2-infected drug-naive patients to PI. Furthermore, interpretation of genotypic data with four available algorithms, developed for interpretation of HIV-1 sequence data, suggested nonoverlapping profiles of drug resistance
Multimode Hong-Ou-Mandel Interferometry
We review some recent experiments based upon multimode two-photon
interference of photon pairs created by spontaneous parametric down-conversion.
The new element provided by these experiments is the inclusion of the
transverse spatial profiles of the pump, signal and idler fields. We discuss
multimode Hong-Ou-Mandel interference, and show that the transverse profile of
the pump beam can be manipulated in order to control two-photon interference.
We present the basic theory and experimental results as well as several
applications to the field of quantum information.Comment: 20 pages, 14 figures, Brief Review to be published in Modern Physics
Letters
Anti-oxLDL autoantibodies and their correlation with lipid profile and nutritional status in adolescents
OBJECTIVE: To investigate whether levels of autoantibodies to oxidized LDL (anti-oxLDL) in the plasma of adolescents correlates with their anthropometric measurements and lipid profiles. METHODS: The study enrolled 150 adolescents aged between 10 and 15 years, recruited from the obesity clinic at Universidade Federal de São Paulo (UNIFESP) (SP) and from public schools in Piracicaba, SP, Brazil. Anthropometric measurements such as body mass index and waist and arm circumferences were used to classify the adolescents as having healthy weight, overweight or obesity. Colorimetric enzymatic methods were used for biochemical lipid profile analysis and ELISA was used to determine anti-oxLDL autoantibody levels. RESULTS: Analysis of anthropometric variables indicated that the obese group's profile was abnormal compared to the healthy weight and overweight groups (p < 0.01), indicating cardiovascular risk. Analysis of the lipid profiles demonstrated statistically significant differences in concentrations of total cholesterol (p = 0.011), HDL-cholesterol (p = 0.001) and LDL-cholesterol (p < 0.042) between the healthy weight group and the obese group. Analysis of plasma anti-oxLDL autoantibodies demonstrated that the overweight (p = 0.012) and obese groups (p < 0.001) had higher values than the healthy weight group. There were also correlations between anti-oxLDL autoantibody levels and anthropometric variables. CONCLUSIONS: In adolescents the presence of anti-oxLDL autoantibodies and metabolic changes to the lipid profile vary in proportion with anthropometric parameters, which makes anti-oxLDL concentration a potential biochemical indicator of risk of metabolic syndrome.OBJETIVO: Avaliar se o conteúdo de auto-anticorpos anti-LDL oxidada (anti-LDLox) no plasma de adolescentes correlaciona-se com suas medidas antropométricas e com o perfil lipídico. MÉTODOS: O estudo incluiu 150 adolescentes com idade entre 10 e 15 anos, recrutados do ambulatório de obesidade da Universidade Federal de São Paulo (UNIFESP) (SP) e de escolas públicas de Piracicaba (SP). Foram avaliadas medidas antropométricas, como índice de massa corporal, circunferência de cintura e do braço, classificando os adolescentes em eutrófico, sobrepeso e obeso. Para as análises bioquímicas, foi realizado o perfil lipídico através de métodos enzimáticos colorimétricos, e para detecção do conteúdo de auto-anticorpos anti-LDLox, utilizou-se o método de ELISA. RESULTADOS: Segundo análises das variáveis antropométricas, o grupo obeso apresentou perfil alterado em relação aos grupos eutrófico e sobrepeso (p < 0,01), indicando risco cardiovascular. Quando o perfil lipídico foi avaliado, observaram-se diferenças estatisticamente significativas para as concentrações de colesterol total (p = 0,011), HDL-colesterol (p = 0,001) e LDL-colesterol (p < 0,042) nos grupos eutrófico e obeso. Para as análises de auto-anticorpos anti-LDLox plasmática, os grupos sobrepeso (p = 0,012) e obeso (p < 0,001) apresentaram valores superiores ao grupo eutrófico. Também houve correlações entre os auto-anticorpos anti-LDLox e variáveis antropométricas. CONCLUSÃO: A presença de auto-anticorpos anti-LDLox em adolescentes e as alterações metabólicas no perfil lipídico variaram de modo proporcional com parâmetros antropométricos, o que torna o conteúdo de anti-LDLox um potencial indicador bioquímico de risco para síndrome metabólica.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade de São PauloUniversidade Federal de São Paulo (UNIFESP) Departamento de PediatriaUniversidade Federal de São Paulo (UNIFESP) Centro de Atendimento e Apoio ao AdolescenteUniversidade Federal de São Paulo (UNIFESP)Universidade Federal de São Paulo (UNIFESP) CAAAUSP Faculdade de Saúde PúblicaUNIFESP, Depto. de PediatriaUNIFESP, Centro de Atendimento e Apoio ao AdolescenteUNIFESP, CAAASciEL
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