SPH simulations of clumps formation by dissipative collision of molecular clouds - I. Non magnetic case

Computer experiments of interstellar cloud collisions were performed with a new smoothed-particle-hydrodynamics (SPH) code. The SPH quantities were calculated by using spatially adaptive smoothing lengths and the SPH fluid equations of motion were solved by means of a hierarchical multiple time-scale leapfrog. Such a combination of methods allows the code to deal with a large range of hydrodynamic quantities. A careful treatment of gas cooling by H, H(2), CO and H II, as well as a heating mechanism by cosmic rays and by H(2) production on grains surface, were also included in the code. The gas model reproduces approximately the typical environment of dark molecular clouds. The experiments were performed by impinging two dynamically identical spherical clouds onto each other with a relative velocity of 10 km s(-1) but with a different impact parameter for each case. Each object has an initial density profile obeying an r(-1)-law with a cutoff radius of 10 pc and with an initial temperature of 20 K. As a main result, cloud-cloud collision triggers fragmentation but in expense of a large amount of energy dissipated, which occurred in the head-on case only. Off-center collision did not allow remnants to fragment along the considered time (similar to 6 Myr). However, it dissipated a considerable amount of orbital energy. Structures as small as 0.1 pc, with densities of similar to 10(4) cm(-3), were observed in the more energetic collision.

Structural modifications in silica sonogels prepared with additions of poly(vinyl alcohol)

Silica wet gels were prepared from acid sonohydrolysis of tetraethoxysilane (TEOS) and additions of poly(vinyl alcohol) (PVA)-water solution. Aerogels were obtained from supercritical CO(2) extraction. The samples were studied by thermal gravimetric (TG) analysis, small-angle X-ray scattering (SAXS), and nitrogen adsorption. The structure of wet gels can be described as a mass fractal with dimension D equal to 2.0 on the whole length scale experimentally probed by SAXS, from similar to 0.3 to similar to 15 nm. Pure and low-PVA-addition wet gels exhibit an upper cutoff accounting for a finite characteristic length xi of the mass fractal structure. Additions , of PVA increase without modifying D, which was attributed to a steric effect of the polymer in the structure. The pore volume fraction of the aerogels diminishes typically about 11% with respect to that of the wet gels, although nitrogen adsorption could be underestimating some porosity. The pore size distribution of the aerogels is shifted toward the mesopore region with the additions of PVA, in a straight relationship with the increase of xi in the wet gels. The thermal stability of the pore size distribution of the aerogels was studied up to 1000 degrees C.

Atividade física habitual de crianças e adolescentes mensurada por pedômetro e sua relação com índices nutricionais

A monitoração dos níveis de prática de atividade física em segmentos da população jovem tem se tornado importante tema de interesse entre especialistas da área. O Objetivo do estudo foi verificar o nível de atividade física de escolares, baseando-se em duas recomendações vigentes, e analisar a existência de associações entre a quantidade de passos/dia e diferentes indicadores de adiposidade corporal. A casuística foi composta por 162 indivíduos de dez a 18 anos (65 do sexo masculino e 97 do sexo feminino). Foram calculados o Índice de Massa Corporal e o percentual de gordura por impedância bioelétrica. O nível de atividade física habitual foi mensurado por meio de pedômetro (New Lifestyles modelo NL-2000) e analisado de acordo com duas recomendações internacionais: Duncan et al. (masculino: 16.000 passos/dia e feminino: 13.000 passos/dia) e Tudor-Locke et al. (masculino: 15.000 passos/dia e feminino: 12.000 passos/dia). O teste t de Student e a ANOVA One-Away (Post Hoc - LSD) compararam os grupos formados. O nível de significância adotado foi de 5% (p£0,05). Dos resultados, apenas 18,5% da amostra cumpriu as recomendações propostas por Duncan e 25,9% cumpriram os pontos de corte propostos por Tudor-Locke et al.. Os adolescentes que não cumpriram as recomendações propostas por Duncan et al., apresentaram valores percentuais de gordura corporal maiores quando comparados aos jovens que cumpriram (p<0,05). Pode-se concluir que uma elevada taxa de jovens não cumpriu as duas recomendações analisadas, bem como, apenas um indicador de adiposidade associou-se com o cumprimento de umas das recomendações.

Confiabilidade e pontuação mínima relacionada à intervenção analgésica de uma escala multidimensional para avaliação de dor pós-operatória em gatos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Concordância entre duas classificações para a aptidão cardiorrespiratória em crianças

OBJETIVO: Analisar a concordância entre duas diferentes tabelas de pontos de corte para a classificação da aptidão cardiorrespiratória em escolares de sete a 10 anos de idade, de ambos os sexos. MÉTODOS: Estudo de delineamento transversal do qual participaram 184 escolares (106 meninos e 78 meninas) de sete a 10 anos de idade. A aptidão cardiorrespiratória dos escolares foi obtida por meio do teste de campo de corrida ou caminhada de nove minutos. Para a discriminação do desempenho no teste, foram utilizados dois critérios ajustados por sexo e idade: Fitnessgram (1987) e o de Bergmann et al (2010). A concordância entre os pontos de corte foi verificada pelo teste de McNemar e pelo índice Kappa, com significância estatística de p<0,05. RESULTADOS: As análises demonstraram que não houve diferença no percentual de jovens classificados como aptos fisicamente (Fitnessgram com 58,1% e Bergmann et al, 59,2%; p=0,864). de forma similar, a concordância entre os pontos de corte apresentou-se moderada (Kappa=0,61). CONCLUSÕES: Ambos os pontos de corte para aptidão cardiorrespiratória classificaram de maneira semelhante os escolares, independentemente do sexo.

Desempenho de diferentes valores críticos de índice de massa corporal na identificação de excesso de gordura corporal e obesidade abdominal em adolescentes

OBJETIVO: Analisar a concordância e eficiência de três valores críticos para índice de massa corporal (IMC) na indicação da obesidade abdominal e do excesso de gordura corporal em adolescentes. MÉTODOS: Análise transversal, em que participaram do estudo 807 jovens, de ambos os sexos (entre 11 e 17 anos), e foram aferidos valores de massa corporal, estatura, circunferência de cintura e gordura corporal relativa. A curva ROC analisou a eficiência dos pontos de corte para índice de massa corporal. RESULTADOS: Os três valores críticos analisados apresentaram moderada concordância na indicação da obesidade abdominal (0,54 a 0,66) e elevados valores de sensibilidade (77,4% a 92,8%) e especificidade (75,6% a 91,6%) para a indicação do estado nutricional. A proposta nacional foi mais sensível na indicação de concomitante excesso de gordura corporal e obesidade abdominal (97,8%). CONCLUSÃO: Todos os valores críticos analisados apresentaram desempenho similar na indicação do estado nutricional e da obesidade abdominal, no entanto a proposta nacional foi mais sensível na indicação de indivíduos obesos com elevado risco cardiovascular.

Utilização das recomendações de nutrientes para estimar prevalência de consumo insuficiente das vitaminas C e E em gestantes

Na gestação ocorrem adaptações que conduzem a um aumento da taxa metabólica basal, caracterizando um estado de alto nível de estresse oxidativo, tornando relevante a avaliação do consumo de nutrientes antioxidantes por mulheres grávidas. Este estudo teve como objetivo estimar a prevalência de consumo insuficiente das vitaminas C e E em gestantes assistidas em serviços públicos de saúde. Estudou-se amostra (n=107) representativa das mulheres no segundo trimestre gestacional atendidas durante o pré-natal nas unidades de atenção básica do município de Botucatu/SP. O consumo foi investigado mediante dois inquéritos recordatórios de 24 horas. Para estimar a prevalência de inadequação de consumo na população, foi utilizado o método EAR como ponto de corte. Diferenças de consumo (em tercis) em relação a fatores socioeconômicos, obstétricos e hábitos de vida foram pesquisadas mediante análise estratificada, adotando-se p<0.05 como nível de significância. As prevalências estimadas de consumo insuficiente das vitaminas C e E foram 60% e 91,5%, respectivamente. Houve associação inversa entre o consumo de vitamina E com paridade e o consumo de vitamina C foi menor nas adolescentes em relação às adultas. Estes resultados indicam a necessidade de intervenções individuais e coletivas de promoção e apoio ao consumo de alimentação saudável por mulheres em idade fértil. Conclui-se que a prevalência de inadequação do consumo das vitaminas C e E é elevada e sem contrastes socioeconômicos.

Liquid-phase blocking sandwich enzyme-linked immunosorbent assay for detection of antibodies against foot-and-mouth disease virus in water buffalo sera

Objective-To develop and apply the liquid-phase blocking sandwich ELISA (BLOCKING-ELISA) for the quantification of antibodies against foot-and-mouth disease virus (FMDV) strains O-1 Campos, A(24) Cruzeiro, and C-3 Indaial.Design-Antibody quantification.Sample Population-158 water buffalo from various premises of São Paulo Stale-Brazil. The sera were collected either from systemically vaccinated or nonvaccinated animals.Procedure-The basic reagents of BLOCKING-ELISA (capture and detector antibodies, virus antigens, and conjugate) were prepared and the reaction was optimized and standardized to quantify water buffalo antibodies against FMDV. An alternative procedure based on mathematical interpolation was adopted to estimate more precisely the antibody 50% competition liters in the BLOCKING-ELISA. These titers were compared with the virus-neutralization test (VNT) titers to determine the correlation between these techniques. The percentages of agreement, cutoff points, and reproducibility also were determined.Results-The antibody liters obtained in the BLOCKING-ELISA had high positive correlation coefficients with VNT, reaching values of 0.90 for O-1 Campos and C-3 Indaial, and 0.82 for the A(24) Cruzeiro (P < 0.0005). The cutoff points obtained by use of the copositivity and conegativity curves allowed determination of high levels of agreement between BLOCKLNG-ELISA and VNT antibody titers against the 3 FMDV strains analyzed.Conclusions-The results characterized by high cor relation coefficients, levels of agreement, and reproducibility indicate that the BLOCKING-ELISA may replace the conventional VNT for detection and quantification of antibodies from water buffalo sera to FMDV.

A MODEL OF THE DEUTERON BASED ON A BREIT TYPE EQUATION

A relativistic treatment of the deuteron and its observables based on a two-body Dirac (Breit) equation, with phenomenological interactions, associated to one-boson exchanges with cutoff masses, is presented. The 16-component wave function for the deuteron (J(pi) = 1+) solution contains four independent radial functions which obey a system of four coupled differential equations of first order. This radial system is numerically integrated, from infinity to the origin, by fixing the value of the deuteron binding energy and using appropriate boundary conditions at infinity. Specific examples of mixtures containing scalar, pseudoscalar and vector like terms are discussed in some detail and several observables of the deuteron are calculated. Our treatment differs from more conventional ones in that nonrelativistic reductions of the order c-2 are not used.

THE VACUUM ENERGY OF QED WITH 4-FERMION INTERACTION

We consider quantum electrodynamics in the quenched approximation including a four-fermion interaction with coupling constant g. The effective potential at stationary points is computed as a function of the coupling constants alpha and g and an ultraviolet cutoff LAMBDA, showing a minimum of energy in the (alpha, g) plane for alpha = alpha(c) = pi/3 and g = infinity. When we go to the continuum limit (LAMBDA --> infinity), keeping finite the dynamical mass, the minimum of energy moves to (alpha = 0, g = 1), which correspond to a point where the theory is trivial.

Ghost poles in the nucleon propagator in the linear sigma model approach and its role in pi N low-energy theorems

Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff and Wilets (BPW), These ghosts violate basic theorems of quantum field theory and their origin is related to the ultraviolet behavior of the model interactions, Recently, Krein et.al, proved that the ghosts disappear when vertex corrections are included in a self-consistent way, softening the interaction sufficiently in the ultraviolet region. In previous studies of pi N scattering using ''dressed'' nucleon propagator and bare vertices, did by Nutt and Wilets in the 70's (NW), it was found that if these poles are explicitly included, the value of the isospin-even amplitude A((+)) is satisfied within 20% at threshold. The absence of a theoretical explanation for the ghosts and the lack of chiral symmetry in these previous studies led us to re-investigate the subject using the approach of the linear sigma-model and study the interplay of low-energy theorems for pi N scattering and ghost poles. For bare interaction vertices we find that ghosts are present in this model as well and that the A((+)) value is badly described, As a first approach to remove these complex poles, we dress the vertices with phenomenological form factors and a reasonable agreement with experiment is achieved, In order to fix the two cutoff parameters, we use the A((+)) value for the chiral limit (m(pi) --> 0) and the experimental value of the isoscalar scattering length, Finally, we test our model by calculating the phase shifts for the S waves and we find a good agreement at threshold. (C) 1997 Elsevier B.V. B.V.

EXPLICIT SOLUTIONS FOR TRUNCATED COULOMB POTENTIAL OBTAINED FROM SUPERSYMMETRY

The Schrodinger equation with the truncated Coulomb potential is solved using the supersymmetric quantum mechanics formalism, with and without the cutoff in the angular momentum potential. We obtain some analytical eigenfunctions and eigenvalues for particular values of the cutoff parameter.

HEAT-KERNEL EXPANSION AT FINITE TEMPERATURE

We show how the zero-temperature result for the heat-kernel asymptotic expansion can be generalized to the finite-temperature one. We observe that this general result depends on the interesting ratio square-root tau/beta, where tau is the regularization parameter and beta = 1/T, so that the zero-temperature limit beta --> infinity corresponds to the cutoff limit tau --> 0. As an example, we discuss some aspects of the axial model at finite temperature.

Electrochemical measurements of oligonucleotides in the presence of chromosomal DNA using membrane-covered carbon electrodes

Substantial improvements in the selectivity of electrochemical measurements of trace nucleic adds are obtained by using membrane-covered carbon disk electrodes. Access to the electrode surface can be manipulated via a judicious choice of the membrane molecular weight cutoff (MWCO). The resulting separation step, performed in situ at the electrode surface, adds a new dimension of selectivity based on molecular size to electroanalysis of nucleic acids, Transport properties are evaluated with respect to the oligonucleotide length and membrane MWCO. A highly selective response is observed for synthetic oligonucleotides in the presence of otherwise interfering chromosomal DNAs. Discrimination among oligonucleotides of different lengths is also possible, Short accumulation periods (1-5 min) are sufficient for convenient measurements of low milligram per liter concentrations.

Detection and quantification of antibodies to Newcastle disease virus in ostrich and rhea sera using a liquid phase blocking enzyme-linked immunosorbent assay

A liquid phase blocking ELISA (LPB-ELISA) was adapted for the detection and quantification of antibodies to Newcastle disease virus. Sera from vaccinated and unvaccinated commercial flocks of ostriches (Struthio camelus) and rheas (Rhea americana) were tested. The purified and nonpurified virus used as the antigen and the capture and detector antibodies were prepared and standardized for this purpose. The hemagglutination-inhibition (HI) test was regarded as the reference method, the cutoff point for the LPB-ELISA was determined by a two-graph receiver operating characteristic analysis. The LPB-ELISA titers regressed significantly (P < 0.0001) on the HI titers with a high correlation coefficient (r = 0.875). The two tests showed good agreement ( = 0.82; P < 0.0001), relative sensitivity (90.91%) and specificity (91.18%), and accuracy (91.02%), suggesting that they are interchangeable.