187 research outputs found
Nonlinear Schrodinger equation with chaotic, random, and nonperiodic nonlinearity
In this paper we deal with a nonlinear Schr\"{o}dinger equation with chaotic,
random, and nonperiodic cubic nonlinearity. Our goal is to study the soliton
evolution, with the strength of the nonlinearity perturbed in the space and
time coordinates and to check its robustness under these conditions. Comparing
with a real system, the perturbation can be related to, e.g., impurities in
crystalline structures, or coupling to a thermal reservoir which, on the
average, enhances the nonlinearity. We also discuss the relevance of such
random perturbations to the dynamics of Bose-Einstein Condensates and their
collective excitations and transport.Comment: 4 pages, 6 figure
Cerebral vasomotor reactivity assessment using transcranial doppler and MRI with apnea test
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULODifferently from previous studies that used Transcranial Doppler (TCD) and functional MRI (fMRI) for cerebral vasomotor reactivity (CVR) assessment in patients with carotid stenosis (CS), we assessed CVR using an identical stimulus, the Breath-Holding Test (BHT). We included 15 patients with CS and 7 age-matched controls to verify whether fMRI responded differently to BHT between groups and to calculate the agreement rate between tests. For TCD, impaired CVR was defined when the mean percentage increase on middle cerebral artery velocities was p31% on 3 consecutive 30-s apnea intercalated by 4-min normal breathing intervals. For fMRI, the percent variation on blood oxygen level-dependent (BOLD) signal intensity in the lentiform nucleus (LN) ipsilateral to the CS (or both LNs for controls) from baseline breathing to apnea was measured. The Euclidian differences between the series of each subject and the series of controls and patients classified it into normal or impaired CVR. We found different percent variations on BOLD-signal intensities between groups (P=0.032). The agreement was good in Controls (85.7%; kappa=0.69) and overall (77.3%; kappa=0.54). We conclude that BHT was feasible for CVR assessment on fMRI and elicited different BOLD responses in patients and controls, with a good overall agreement between the tests.Differently from previous studies that used Transcranial Doppler (TCD) and functional MRI (fMRI) for cerebral vasomotor reactivity (CVR) assessment in patients with carotid stenosis (CS), we assessed CVR using an identical stimulus, the Breath-Holding Test (BHT). We included 15 patients with CS and 7 age-matched controls to verify whether fMRI responded differently to BHT between groups and to calculate the agreement rate between tests. For TCD, impaired CVR was defined when the mean percentage increase on middle cerebral artery velocities was p31% on 3 consecutive 30-s apnea intercalated by 4-min normal breathing intervals. For fMRI, the percent variation on blood oxygen level-dependent (BOLD) signal intensity in the lentiform nucleus (LN) ipsilateral to the CS (or both LNs for controls) from baseline breathing to apnea was measured. The Euclidian differences between the series of each subject and the series of controls and patients classified it into normal or impaired CVR. We found different percent variations on BOLD-signal intensities between groups (P=0.032). The agreement was good in Controls (85.7%, kappa=0.69) and overall (77.3%, kappa=0.54). We conclude that BHT was feasible for CVR assessment on fMRI and elicited different BOLD responses in patients and controls, with a good overall agreement between the tests.491118CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2010/52027-1, 2013/07559-3480976/2010-4The institutional support of Prof. Fernando Cendes and the Neurovascular Study Group, as well as the kind assistance of Ms. Isilda Assumpcao (RN) and team, are gratefully acknowledged. This research was supported by FAPESP (Process 2010/52027-1 and 2013/07559-3) and CNPq (Process 480976/2010-4)
Cratylia argentea (Fabacea): parâmetros fitotécnicos e multifuncionalidade na bacia do Ribeirão Jequitibá, região central de Minas Gerais.
Edição dos resumos do VIII Congresso Brasileiro de Agroecologia, Porto Alegre, 2013
Generation of two-photon EPR and Wstates
In this paper we present a scheme for generation of two-photon EPR and W
states in the cavity QED context. The scheme requires only one three-level
Rydberg atom and two or three cavities. The atom is sent to interact with
cavities previously prepared in vacuum states, via two-photon process. An
appropriate choice of the interaction times one obtains the mentioned state
with maximized fidelities. These specific times and the values of success
probability and fidelity are discussed.Comment: 4 pages, 5 figure
Density matrix reconstruction from displaced photon number distributions
We consider state reconstruction from the measurement statistics of phase
space observables generated by photon number states. The results are obtained
by inverting certain infinite matrices. In particular, we obtain reconstruction
formulas, each of which involves only a single phase space observable.Comment: 19 page
Negativity of the Wigner function as an indicator of nonclassicality
A measure of nonclassicality of quantum states based on the volume of the
negative part of the Wigner function is proposed. We analyze this quantity for
Fock states, squeezed displaced Fock states and cat-like states defined as
coherent superposition of two Gaussian wave packets.Comment: 10 pages, 7 figure
Impact of changes at the Candida albicans cell surface upon immunogenicity and colonisation in the gastrointestinal tract
Acknowledgements This work was supported by a programme grant from the UK Medical Research Council (MR/M026663/1; MR/M026663/2) and by the Medical Research Council Centre for Medical Mycology (MR/N006364/1; MR/N006364/2). NARG acknowledges Wellcome support for a Senior Investigator (101873/Z/13/Z), Collaborative (200208/A/15/Z; 215599/Z/19/Z) and Strategic Awards (097377/Z11/Z). LR, SHD and AWW received core funding support from the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS) division. MGN was supported by an ERC Advanced Grant (833247) and a Spinoza Grant of the Netherlands Organization for Scientific Research.Peer reviewedPublisher PD
Recommended from our members
Retrospective analysis of risk factors and gaps in prevention strategies for mother-to-child HIV transmission in Rio de Janeiro, Brazil
Background
Despite great progress made in methods to prevent mother-to-child transmission of HIV (MTCT), delivery and uptake of these measures remains a challenge in many countries. Although the Brazilian Ministry of Health aimed to eliminate MTCT by 2015, infection still occured in 15–24% of infants born to HIV-infected mothers. We sought to identify remaining factors that constrain MTCT elimination.
Methods
We conducted a retrospective, matched case-control study by reviewing hospital charts of infants born to HIV-infected mothers between 1997 and 2014 at three MTCT reference hospitals in the Rio de Janeiro metropolitan area. Cases were defined as HIV-exposed children with two positive HIV tests before 18 months of age; controls were defined as HIV-exposed children with two negative HIV tests before 18 months of age. We performed bivariate and MTCT cascade analyses to identify risk factors for MTCT and gaps in prevention services.
Results
We included 435 infants and their mothers (145 cases, 290 controls). Bivariate analyses of MTCT preventative care (PMTCT) indicated that cases were less likely to complete all individual measures in the antenatal, delivery, and postnatal period (p < 0.05). Assessing completion of the PMTCT cascade, the sequential steps of PMTCT interventions, we found inadequate retention in care among both cases and controls, and cases were significantly less likely than controls to continue receiving care throughout the cascade (p < 0.05). Motives for incompletion of PMTCT measures included infrastructural issues, such as HIV test results not being returned, but were most often due to lack of care-seeking. Over the course of the study period, PMTCT completion improved, although it remained below the 95% target for antenatal care, HIV testing, and antenatal ART set by the WHO. Adding concern, evaluation of co-infections indicated that case infants were also more likely to have congenital syphilis (OR: 4.29; 95% CI: 1.66 to 11.11).
Conclusions
While PMTCT coverage has improved over the years, completion of services remains insufficient. Along with interventions to promote care-seeking behaviour, increased infrastructural support for PMTCT services is needed to meet the HIV MTCT elimination goal in Brazil as well as address rising national rates of congenital syphilis
- …