221 research outputs found

    SU(3) Quantum Interferometry with single-photon input pulses

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    We develop a framework for solving the action of a three-channel passive optical interferometer on single-photon pulse inputs to each channel using SU(3) group-theoretic methods, which can be readily generalized to higher-order photon-coincidence experiments. We show that features of the coincidence plots vs relative time delays of photons yield information about permanents, immanants, and determinants of the interferometer SU(3) matrix

    Lost and found: the radial quantum number of Laguerre-Gauss modes

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    We introduce an operator linked with the radial index in the Laguerre-Gauss modes of a two-dimensional harmonic oscillator in cylindrical coordinates. We discuss ladder operators for this variable, and confirm that they obey the commutation relations of the su(1,1) algebra. Using this fact, we examine how basic quantum optical concepts can be recast in terms of radial modes.Comment: Some minor typos fixed

    Exchange Gate on the Qudit Space and Fock Space

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    We construct the exchange gate with small elementary gates on the space of qudits, which consist of three controlled shift gates and three "reverse" gates. This is a natural extension of the qubit case. We also consider a similar subject on the Fock space, but in this case we meet with some different situation. However we can construct the exchange gate by making use of generalized coherent operator based on the Lie algebra su(2) which is a well--known method in Quantum Optics. We moreover make a brief comment on "imperfect clone".Comment: Latex File, 12 pages. I could solve the problems in Sec. 3 in the preceding manuscript, so many corrections including the title were mad

    Performance of cryptococcal antigen lateral flow assay in serum, cerebrospinal fluid, whole blood, and urine in HIV-infected patients with culture-proven cryptococcal meningitis admitted at a Brazilian referral center

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    Cryptococcal meningitis is the most common cause of opportunistic meningitis in HIV-infected patients in Brazil and causes unacceptable high mortality rates. In this study, HIV-infected patients with a first episode of culture-proven cryptococcal meningitis in cerebrospinal fluid (CSF) were prospectively included in order to evaluate sensitivity of cryptococcal antigen (CrAg) lateral flow assay (LFA) in serum, CSF, whole blood (fingerstick), and fresh urine. In addition, HIV-infected patients with other neurological confirmed diseases were included in order to evaluate the specificity of CrAg LFA in serum. Twenty patients with cryptococcal meningitis were included and in 19 of them, CrAg LFA in CSF, serum, and whole blood were positive (95% sensitivity). In 18 patients, India ink test was positive in CSF (90% sensitivity), and in 16 cases, CrAg LFA was positive in urine (80% sensitivity). Thirty-six HIV-infected patients with other neurological diseases had negative results of CrAg LFA in serum (100% specificity). In conclusion, CrAg LFA in serum, CSF, and whole blood showed high sensitivity and specificity. Whole blood CrAg LFA seems to be a good and reliable strategy to improve AIDS-related cryptococcal meningitis diagnosis in Brazil

    Nutritional status of iodine in pregnant women in Catalonia (Spain): study on hygiene-dietetic habits and iodine in urine

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    <p>Abstract</p> <p>Background</p> <p>It is a priority to achieve an adequate nutritional status of iodine during pregnancy since iodine deficiency in this population may have repercussions on the mother during both gestation and post partum as well as on the foetus, the neonate and the child at different ages. According to the WHO, iodine deficiency is the most frequent cause of mental retardation and irrreversible cerebral lesions around the world. However, few studies have been published on the nutritional status of iodine in the pregnant population within the Primary Care setting, a health care level which plays an essential role in the education and control of pregnant women. Therefore, <b>the aim of the present study </b>is: 1.- To know the hygiene-dietetic habits related to the intake of foods rich in iodine and smoking during pregnancy. 2.- To determine the prevalence of iodine deficiency and the factors associated with its appearance during pregnancy.</p> <p>Methods/design</p> <p>We will perform a cluster randomised, controlled, multicentre trial. Randomisation unit: Primary Care Team. Study population: 898 pregnant women over the age of 17 years attending consultation to a midwife during the first trimester of pregnancy in the participating primary care centres. Outcome measures: consumption of iodine-rich foods and iodine deficiency. Points of assessment: each trimester of the gestation. Intervention: group education during the first trimester of gestation on healthy hygiene-dietetic habits and the importance of an adequate iodine nutritional status. Statistical analysis: descriptive analysis of all variables will be performed as well as multilevel logistic regression. All analyses will be done carried out on an intention to treat basis and will be fitted for potential confounding factors and variables of clinical importance.</p> <p>Discussion</p> <p>Evidence of generalised iodine deficiency during pregnancy could lead to the promotion of interventions of prevention such as how to improve and intensify health care educational programmes for pregnant women.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01301768">NCT01301768</a></p

    Phocine distemper Virus: Current knowledge and future directions

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    Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years
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