Expansion of a Bose-Einstein Condensate in an atomic waveguide

The expansion of a Bose-Einstein condensate in an atomic waveguide is analyzed. We study different regimes of expansion, and identify a transient regime between one-dimensional and three-dimensional dynamics, in which the properties of the condensate and its further expansion can be well explained by reducing the transversal dynamics to a two-level system. The relevance of this regime in current experiments is discussed.Comment: 4 pages, 3 figs, Accepted for publication in Phys. Rev.

Spatially Variable Reaction In The Formation Of Anodically Grown Porous Silicon Structures

In porous silicon formations there is an increase of dissolution rate at the fluorine-covered sites of the silicon surface due to the presence of excess electrons coming from oxidation of molecular hydrogen at the passivated (hydrogen-covered) sites. The dissolution rate increase in the presence of excess charge at the fluorine-covered sites is experimentally measured and a theoretical investigation is carried out by a semiempirical Hartree-Fock calculation. This spatially variable dissolution generates the porous silicon surface. © 1995 American Institute of Physics.78159059

Role Of Disorder In The Conduction Mechanism In Polyanilines

We present the first theoretical calculations of the electronic structure of long (200 rings) linear chains of polyaniline, ranging in composition from leucoemeraldine to emeraldine, allowing for compositional disorder in that the sequence of quinoid-benzenoid groups is random. We show that random protonation of the disordered polymers may induce p-type conductivity: This process pulls the Fermi energy down into the valence band, past localized band tails, to extended states. The effect is only seen if disorder is taken into account. © 1989 The American Physical Society.63778678

Mean field effects in a trapped classical gas

In this article, we investigate mean field effects for a bosonic gas harmonically trapped above the transition temperature in the collisionless regime. We point out that those effects can play also a role in low dimensional system. Our treatment relies on the Boltzmann equation with the inclusion of the mean field term. The equilibrium state is first discussed. The dispersion relation for collective oscillations (monopole, quadrupole, dipole modes) is then derived. In particular, our treatment gives the frequency of the monopole mode in an isotropic and harmonic trap in the presence of mean field in all dimensions.Comment: 4 pages, no figure submitted to Phys. Rev.

Antibiotic resistance genes detected in the marine sponge <i>Petromica citrina</i> from Brazilian coast

Although antibiotic-resistant pathogens pose a significant threat to human health, the environmental reservoirs of the resistance determinants are still poorly understood. This study reports the detection of resistance genes (ermB, mecA, mupA, qnrA, qnrB and tetL) to antibiotics among certain culturable and unculturable bacteria associated with the marine sponge Petromica citrina. The antimicrobial activities elicited by P. citrina and its associated bacteria are also described. The results indicate that the marine environment could play an important role in the development of antibiotic resistance and the dissemination of resistance genes among bacteria

Controlo químico de bebidas adulteradas em crimes facilitados com drogas

Although drugs are developed with therapeutics intentions, sometimes some substances are used for purposes other than those the pharmacologist had in mind. The word “drug” also involves psychoactive substances that can be used for medicinal or non-medicinal purposes in which it is included substances that are legal or illegal. The use of drugs for intentions other than their therapeutic purposes has become a growing public concern making their study very important from the toxicological standpoint. When alleged victims report that they were robbed or assaulted while incapacitated by a drug, toxicological chemical analysis is imperative to help substantiate the victim’s claim. These criminal offenses are known as drug facilitated crimes.The branch of science dedicated to toxicology studies has two application fields, forensic and analytical toxicology, that are interdisciplinary and that comprise all the scientific facts related with crimes committed through the use of drugs. Most often, the cases of crimes facilitated by drugs involve substances that have strong central nervous system depressant effects that are availed to easily render victims to robberies or sexual assaults. As new drugs are continuously being synthetized and new methods are used for drugging victims without their knowledge or consent it is important to develop new analytical methods that can assist in the investigation for figuring out all the details about this sort of crimes or enable ways of their prevention. For example, one way of drugging victims without being aware of is through drink spiking in social entertainment places, during parties, raves, etc. In these cases, the spiked beverages are the “crime weapons”. In this paper, it will be presented the relation of drug facilitated crimes and the toxicology science and also a review focused on the available analytical methods for the detection of adulterated beverages with drugs. Embora os fármacos sejam desenvolvidos com fins terapêuticos, às vezes algumas substâncias são uti- lizadas com objetivos diferentes daqueles que o farmacologista teve em mente. A palavra fármaco também contempla substâncias psicoativas que podem usar-se com objetivos medicinais ou não-medicinais nos quais são incluídas substâncias legais e ilegais (comummente designadas por “drogas”). O uso de algumas substâncias com intenções não terapêuticas tornou-se um problema de saúde pública crescente, muito importante do ponto de vista de estudos toxicológicos. Quando supostas vítimas informam que foram roubadas ou assaltadas enquanto incapacitadas por uma droga, a análise química toxicológica é imperativa para ajudar a fundamentar a denúncia da vítima. Este tipo de ofensas criminais denomina-se por crimes facilitados por drogas. O ramo da ciência dedicado a estudos de toxicologia envolve a toxicologia forense e analítica, que são interdisciplinares e que compreendem todos os factos científicos relacionados com crimes facilitados por drogas. Normalmente, os casos de crimes facilitados por drogas implicam substâncias com fortes efeitos depressores do sistema nervoso central, e que são usadas para transformar as pessoas em vítimas fáceis de roubos ou assaltos sexuais. Dado que novas drogas são continuamente sintetizadas e, também surgem novos métodos para drogar vítimas sem o seu consentimento ou conhecimento, é imperativo desenvolver novas metodologias de análise química e toxicológica, para auxiliar na investigação científica de todos os factos dos crimes cometidos com drogas, ou ainda possibilitar a implementação de medidas de prevenção. Por exem- plo, um modo de drogar vítimas sem o seu conhecimento é através da colocação disfarçada de drogas em bebidas, nos locais de diversão social, em festas, em “raves”, etc.. Nestes casos, as bebidas adulteradas são as “armas do crime”. Neste artigo, será abordado o enquadramento de crimes facilitados por drogas nas ciências de análise química toxicológica e também, será realizada uma revisão bibliográfica das metodologias analíticas disponíveis para o controlo químico toxicológico de bebidas adulteradas com drogas de abuso.

Seminal quality, testicle and epididymis morphology of bulls fed a diet containing gossypol

The objective was to evaluate the effect of intake of free gossypol on sperm quality and morphology of the testicles and epididymis of Nelore bulls. Twelve bulls were fed diets containing 3.3g of free gossypol/bull/day (cottonseed) (Group 1, n = 6) and a diet free of gossypol (Group 2, n = 6), respectively. Semen samples were collected in the beginning and end of the experiment which lasted 73 days. In the end of the study the testes and epididymis of bulls were removed to study the effect of free gossypol on histological characteristics. The average consumption of 3.3g of free gossypol/bull/day (mean 7.1mg of free gossypol/kg/day) reduced motility and sperm concentration and increased the percentage of major and total sperm defects, as well as the animals showing testes with seminiferous tubules of smaller thickness, fewer layers of spermatogenic lineage cells, smaller epididymal epithelium thickness and smaller number of sperm within the epididymal ducts, compared to animals with a diet free of gossypol (Group 2). The consumption of 3.3g of free gossypol/bull/day led to changes in morphology and morphometry of the testes and epididymis and reduced sperm quality of bulls.Objetivou-se avaliar o efeito da ingestão de gossipol livre sobre a qualidade espermática e a morfologia dos testículos e dos epidídimos de touros da raça Nelore. Doze touros receberam dieta contendo 3,3g de gossipol livre/touro/dia (caroço de algodão) (Grupo 1, n=6) e dieta isenta de gossipol (Grupo 2, n=6), respectivamente. Foram realizadas coletas de sêmen no início e no final do experimento, que teve duração de 73 dias. Ao final do estudo, foram retirados os testículos e os epidídimos dos touros para se estudar o efeito do gossipol livre sobre as características histológicas. O consumo médio de 3,3g de gossipol livre/touro/dia (média 7,1mg de gossipol livre/kg/dia) reduziu a motilidade e a concentração espermática e aumentou a porcentagem de defeitos espermáticos maiores e totais. Além disso, os animais apresentaram testículos com túbulos seminíferos de menor espessura de parede, menor número de camadas de células espermatogênicas, menor espessura do epitélio epididimário e menor número de espermatozoide no interior dos ductos epidídimários, em relação aos animais com dieta isenta de gossipol (Grupo 2). O consumo de 3,3g de gossipol livre/touro/dia acarretou alterações na morfologia e na morfometria dos testículos e dos epidídimos e reduziu a qualidade espermática dos touros.Universidade de Cuiabá Faculdade de Medicina VeterináriaUFMS Faculdade de Medicina Veterinária e ZootecniaEpamigUniversidade Federal do Mato GrossoUNIFESP-EPMUNIFESP, EPMSciEL

Inflationary models inducing non-Gaussian metric fluctuations

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then transferred into curvature fluctuations. The probability distribution functions of the metric perturbation at the end of inflation are computed. This provides a guideline for designing strategies to search for non-Gaussian signals in future CMB and large scale structure surveys.Comment: 4 pages, 7 figure

Síndrome De Transfusão Feto-fetal: Neurodesenvolvimento De Lactentes Tratados Com Cirurgia A Laser

To assess the neurodevelopmental functions of survivors of twin-twin transfusion syndrome (TTTS) treated by fetoscopic laser coagulation (FLC), during the first year of life, comparing them to a control group; and to verify the influence of specific variables on neurodevelopment. Method: This was a prospective, longitudinal study. The sample comprised 33 monochorionic diamniotic twins who underwent FLC for treatment of TTTS and 22 full-term infants of single-fetus pregnancies. Bayley Scales of Infant and Toddler Development Screening Test were used for evaluation. Prenatal, perinatal and postnatal information were obtained. Results: There was an increased frequency of infants in the TTTS group with inadequate performance compared to the control group. The identified variables (fetal donor, low economic income and cardiorespiratory disease) negatively impacted expressive communication and fine motor skills. Conclusion: Although through follow-up is recommended in all TTTS survivors, particular attention is required for the high-risk group as defined in this study. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All rights reserved.74430731