Optical manipulation of quantum fluids in semiconductor microcavities

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Ciencias, [Departamento de Física de Materiales]. Fecha de lectura: 22-02-201

Hybrid Model For Word Prediction Using Naive Bayes and Latent Information

Historically, the Natural Language Processing area has been given too much attention by many researchers. One of the main motivation beyond this interest is related to the word prediction problem, which states that given a set words in a sentence, one can recommend the next word. In literature, this problem is solved by methods based on syntactic or semantic analysis. Solely, each of these analysis cannot achieve practical results for end-user applications. For instance, the Latent Semantic Analysis can handle semantic features of text, but cannot suggest words considering syntactical rules. On the other hand, there are models that treat both methods together and achieve state-of-the-art results, e.g. Deep Learning. These models can demand high computational effort, which can make the model infeasible for certain types of applications. With the advance of the technology and mathematical models, it is possible to develop faster systems with more accuracy. This work proposes a hybrid word suggestion model, based on Naive Bayes and Latent Semantic Analysis, considering neighbouring words around unfilled gaps. Results show that this model could achieve 44.2% of accuracy in the MSR Sentence Completion Challenge

Vortex stability and permanent flow in nonequilibrium polariton condensates

The following article appeared in Journal of Applied Physics 109.10 (2011): 102406 and may be found at http://scitation.aip.org/content/aip/journal/jap/109/10/10.1063/1.3576151We study the effects of imprinting a single-quantized vortex on the steady state of a microcavity exciton-polariton condensate generated via parametric scattering. Interestingly we observe two distinct regimes: In the first case, at low polariton densities, the effect of the pulsed probe, containing the vortex state, is to generate a gain response in the condensate lasting for tens of picoseconds during which no dissipation of the circulating currents is detected. In the second regime, at higher densities, the gain lasts much less and the circulation is imprinted directly into the steady state, which acquires permanent rotation for as long as the vortex remains within the condensate. We use two different ways of measuring the circulation of the condensate and demonstrate that in both cases, polariton condensation in the parametric scattering regime can sustain permanent supercurrentsThis work was partially supported by the Spanish MEC (MAT2008-01555 and QOIT-CSD2006-00019), the CAM (S2009/ESP-1503) and FP7 ITNs “Clermont4” (235114). D.S. acknowledges financial support from the Ramón y Cajal program. G.T. is grateful for the FPI scholarship from the Ministerio de Ciencia e Innovació

Sero-occurrence of anti-Toxoplasma gondii antibodies and vertical transmission in slaughtered beef cows (Bos indicus) Soro ocorrência de anticorpos contra Toxoplasma gondii e transmissão vertical em vacas de corte (Bos indicus) abatidas

Abstract Toxoplasma gondii is a protozoan parasite recognized as an important public health problem. The objective of the present study was to evaluate the occurrence of anti-T. gondii antibodies in pregnant and non pregnant zebus' breed beef cows (Bos indicus), their fetuses, killed at an abattoir in northern of Paraná state. In the present study 169 cows were evaluated, 92 pregnant (in different stages of gestation) and 77 non pregnant. Sero-occurrence of anti-T. gondii antibodies was performed by Indirect uorescent antibody test (IFAT) considering positive animals with titers ≥ 50 for cows and ≥ 25 for fetuses. Blood (with EDTA) from pregnant cows and blood and tissue samples (brain, lung, heart, and liver) from their fetuses were collected and used for mouse bioassay. Antibodies against T. gondii were observed in 26.0% of cows and 2.5% of fetuses. There was no statistical difference when prevalence of toxoplasmosis was compared between pregnant (23.9%), and non-pregnant (28.6%) animals, and age of gestation (p > 0.59). However, the occurrence of anti-T.gondii antibodies increased with age of animals (p=0.004). Mouse bioassay showed three fetuses positives (3.2%), however, none T. gondii strain was isolated. The present study showed that transplacental transmission of T. gondii naturally occurs in zebu beef cows from Brazil, however, in low rate (5.4%). The anti-T. gondii antibodies occurrence increase with the age of animals, which could be related to the fact that main transmission in cattle T. gondii is horizontal. Key words: Toxoplasmosis, zebu, vertical transmission Resumo Toxoplasma gondii é um protozoário reconhecido como um dos mais importantes parasitas em saúde pública. O objetivo do presente estudo foi avaliar a ocorrência de anticorpos contra T. gondii em vacas de corte zebuínas (Bos indicus) gestantes, e seus fetos, bem como, em vacas não gestantes abatidas em um matadouro no norte do Paraná. No presente estudo foram avaliadas 169 vacas, 92 prenhas (em diferentes fases de gestação) e 77 não prenhas. A ocorrência de anticorpos contra T. gondii foi realizada por meio da reação de imuno uorescência indireta (IFI) considerando animais positivos aqueles com títulos ≥ 50 para as vacas e ≥ 25 para os fetos. Sangue (EDTA) de vacas prenhas e amostras de sangue e tecidos (cérebro, pulmão, coração, e fígado) de seus fetos foram coletadas e utilizadas para o bioensaio em camundongos. Anticorpos contra T. gondii foram observados em 26,0% das vacas e em 2,5% dos fetos Não houve diferença quando a soropositividade de anticorpos foi comparado entre vacas gestantes (23,9%), e não gestantes (28,6%), bem como, a idade da gestação (p > 0,59). No entanto, a ocorrência de anticorpos aumentou com a idade dos animais (p = 0,004). O bioensaio mostrou três fetos positivos (3,2%), porém, nenhuma cepa foi isolada. O presente estudo mostrou que a transmissão transplacentária de T. gondii ocorre naturalmente em vacas de corte zebuínas do Brasil, no entanto, esta ocorrência foi baixa (5,4%). A maior ocorrência de anticorpos associada com a idade dos animais poderia estar relacionada a transmissão horizontal do T. gondii nestes animais