Atomic Charge Transfer-counter Polarization Effects Determine Infrared Ch Intensities Of Hydrocarbons: A Quantum Theory Of Atoms In Molecules Model.

Atomic charge transfer-counter polarization effects determine most of the infrared fundamental CH intensities of simple hydrocarbons, methane, ethylene, ethane, propyne, cyclopropane and allene. The quantum theory of atoms in molecules/charge-charge flux-dipole flux model predicted the values of 30 CH intensities ranging from 0 to 123 km mol(-1) with a root mean square (rms) error of only 4.2 km mol(-1) without including a specific equilibrium atomic charge term. Sums of the contributions from terms involving charge flux and/or dipole flux averaged 20.3 km mol(-1), about ten times larger than the average charge contribution of 2.0 km mol(-1). The only notable exceptions are the CH stretching and bending intensities of acetylene and two of the propyne vibrations for hydrogens bound to sp hybridized carbon atoms. Calculations were carried out at four quantum levels, MP2/6-311++G(3d,3p), MP2/cc-pVTZ, QCISD/6-311++G(3d,3p) and QCISD/cc-pVTZ. The results calculated at the QCISD level are the most accurate among the four with root mean square errors of 4.7 and 5.0 km mol(-1) for the 6-311++G(3d,3p) and cc-pVTZ basis sets. These values are close to the estimated aggregate experimental error of the hydrocarbon intensities, 4.0 km mol(-1). The atomic charge transfer-counter polarization effect is much larger than the charge effect for the results of all four quantum levels. Charge transfer-counter polarization effects are expected to also be important in vibrations of more polar molecules for which equilibrium charge contributions can be large.

Efeito das intera����es hiperconjugativas na constante de acoplamento ��J CH da hexametilenotetramina e do adamantano: estudo te��rico e experimental

The objective of this work was to determine the influence of hyperconjugative interactions on the ��J CH coupling constant for hexamethylenetetramine (1) and adamantane (2). For this end, theoretical and experimental ��J CH were obtained and hyperconjugative interactions were investigated using NBO. It was observed, theoretically and experimentally, that ��J CH in 1 is 20 Hz larger than in 2, mainly due to the nN��s*C-H hyperconjugative interaction. This interaction occurs only in 1, with an energy of 9.30 kcal mol-1. It increases the s-character of the carbon atom in the C-H bond and the occupancy of the sigma*C-H orbital in (1).

Influ��ncia da temperatura do ar de secagem no calor latente de vaporiza����o de ��gua em feij��o macassar (Vigna unguiculata (L.) Walp.), variedade sempre-verde

In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.

Entre o ocio e o negocio : teses acerca da anatomia do lazer

Universidade Estadual de Campinas . Faculdade de Educa����o F��sica

Avers��o alimentar adquirida e qualidade de vida em mulheres com neoplasia mam��ria

OBJETIVO: Avaliar o comportamento alimentar de mulheres com c��ncer de mama submetidas �� quimioterapia, e sua rela����o com a qualidade de vida destas pacientes. M��TODOS: A partir de um ensaio cl��nico do tipo antes e depois, selecionou-se 25 mulheres do Hospital AC Camargo (S��o Paulo, Brasil) durante o per��odo de outubro de 2005 a abril de 2006. As pacientes inclusas no estudo apresentavam diagn��stico de c��ncer de mama, com estadiamento I e II e indica����o de tratamento quimioter��pico adjuvante. Nos momentos T0 (antes) e T1 (ap��s o tratamento quimioter��pico), o comportamento alimentar (consumo e avers��o alimentar) foi avaliado por tr��s recordat��rios 24 horas e um question��rio Food Action, respectivamente. A qualidade de vida foi monitorada por meio do question��rio Functional Assessment of Cancer Therapy-Breast. RESULTADOS: Ap��s o tratamento quimioter��pico (T1), o consumo de macro e micronutrientes n��o apresentou altera����es significantes, mas o consumo de frutas e sucos aumentou (p=0,03). Perfil inverso foi observado em rela����o �� prefer��ncia por caf�� preto (p=0,01) e pelo grupo de bebidas (p<0,001). Alimentos gordurosos (38%), latic��nios (23%), caf�� preto (15%), chá (15%), chocolate (7%) e carne vermelha (7%) foram os principais alimentos associados ao desconforto das pacientes. An��lises de qualidade de vida mostraram que o tratamento quimioter��pico promoveu significante redu����o no bem estar f��sico (p<0,01). Ap��s o mesmo, algumas vari��veis do comportamento alimentar foram significantemente correlacionadas com os par��metros de qualidade de vida. CONCLUS��O: A rela����o bilateral entre comportamento alimentar e qualidade de vida foi modificada negativamente pelo tratamento quimioter��pico.

Contraceptive use and associated factors among adolescents on Santiago Island - Cape Verde - Western Africa

OBJECTIVE: to estimate the prevalence of contraceptive use and associated factors among adolescents attending public schools on Santiago Island, Cape Verde. METHODS: a cross-sectional study was carried out with 368 sexually active adolescents aged 13-17years attending eight public elementary and high schools, randomly selected, on Santiago Island, Cape Verde, between January and March 2007. Poisson regression with robust variance was used for the multiple analysis of risk factors, at a 5% level of significance. RESULTS: among 368 adolescents, 69.3% reported having used a contraceptive method during the last act of sexual intercourse. The most frequently used method were condom (94.9%) and pill (26.4%). Factors significantly and positively associated with contraceptive use were: living in the capital (PR=1.23; CI95%: 1.07; 1.39); having dated and had sexual intercourse (PR =1.53; CI95%: 1.14;2.06); and having more than nine years of schooling (PR=1.19; CI95%: 1.02; 1.38). CONCLUSIONS: more educated adolescents who studied in Praia (the capital city) and were dating at the time of the study were more likely to use contraception. The high prevalence of condom use and the association between contraception use and years of schooling among adolescents may indicate that sexual and reproductive health policies have produced positive outcomes that may account for the decrease in HIV infection.

Agricultura e meio ambiente em Rio Verde (GO)

A moderniza����o da agropcu��ria brasileira possibilitou aumento da produ����o atrav��s da expans��o das monoculturas, como a soja. Alta demanda e bons pre��os no mercado internacional incentivaram o cultivo dessa oleaginosa, principalmente no Cerrado. Em que pese seus benef��cios econ��micos, a sojicultura realizada nestes moldes, com grandes aportes mec��nicos e qu��micos e concentra����o fundi��ria, causa impactos ambientais e sociais. Desmatamento, polui����o de cursos d����gua, eros��o, compacta����o de solos, intoxica����o e concentra����o de terra s��o alguns desses problemas. Esta pesquisa objetivou verificar desmatamento, contamina����o de cursos d����gua por agrot��xico e intoxica����o no munic��pio maior produtor de soja de Goi��s, Rio Verde. Foram utilizados mapas de uso do solo de Rio Verde, dos anos 1975, 1989 e 2005, autos de infra����o emitidos por ��rg��os de fiscaliza����o ambiental, resultado de an��lises de res��duos de agrot��xicos na ��gua destinada ao abastecimento p��blico e casos de intoxica����o por agrot��xico. A presen��a e gravidade do desmatamento, que ocorreu entre 1975 e 2005, puderam ser detectadas pelos dados analisados. J�� os dados sobre intoxica����o, por possivelmente serem subnotificados, revelaram um problema de sa��de p��blica. Concluiu-se a necessidade de a����es pelo poder p��blico de fiscaliza����o ambiental em Rio Verde, de medidas que melhorem a notifica����o de casos de intoxica����o, e da promo����o de incentivos ��queles agricultores que respeitam as leis ambientais

Factors associated with sexual initiation and condom use among adolescents on Santiago Island, Cape Verde, West Africa

Foram analisados fatores associados ao in��cio da vida sexual de adolescentes na Ilha de Santiago, Cabo Verde, segundo sexo. Estudo realizado com amostra probabil��stica e representativa de 768 adolescentes, age 13-17 anos, de escolas secund��rias p��blicas da Ilha de Santiago em 2007. A associa����o foi testada pelo teste de propor����o, qui-quadrado de Pearson ou Fisher e regress��o log��stica. Nos rapazes, os fatores associados ao in��cio da vida sexual foram: idade maior que 14 anos, ser cat��lico e consumo de bebidas alco��licas. Para meninas: escolaridade maior que nove anos e ter parceiro afetivo-sexual. Ao contr��rio de outros contextos da ��frica Subsaariana, foram constatadas taxas elevadas de uso de preservativo por adolescentes no in��cio da vida sexual. Os adolescentes podem iniciar a vida sexual de maneira mais segura se tiverem informa����o, educa����o sexual e acesso a m��todos de preven����o �� gravidez e ��s DST. Este artigo oferece elementos para a reflex��o sobre o delineamento de pol��ticas de redu����o da vulnerabilidade dos jovens ��s DST/AIDS e sobre os limites e desafios da promo����o do uso do preservativo e educa����o sexual, focando as rela����es desiguais de g��nero

Electron collisions with the CH(2)O-H(2)O complex

We report cross sections for elastic collisions of low-energy electrons with the CH(2)O-H(2)O complex. We employed the Schwinger multichannel method with pseudopotentials in the static-exchange and in the static-exchange-polarization approximations for energies from 0.1 to 20 eV. We considered four different hydrogen-bonded structures for the complex that were generated by classical Monte Carlo simulations. Our aim is to investigate the effect of the water molecule on the pi* shape resonance of formaldehyde. Previous studies reported a pi* shape resonance for CH(2)O at around 1 eV. The resonance positions of the complexes appear at lower energies in all cases due to the mutual polarization between the two molecules. This indicates that the presence of water may favor dissociation by electron impact and may lead to an important effect on strand breaking in wet DNA by electron impact.

Synthesis and characterization of the [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl](PF(6))(2) dimer

The polymetallic [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru( bpy)(2)Cl](PF(6))(2) complex (bpy = 2,2`-bipyridine, BPE = trans- 1,2-bis(4-pyridil) ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru(3)O] moiety with a [ Ru( bpy) 2( BPE) Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS) spectrometry. The [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl] (2+) doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)(2)(BPE)] charge-transfer bands and to the [Ru(3)O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at - 1.07 V, 0.13 V, 1.17 V, 2.91 V and - 1.29 V (vs SHE) assigned to the [Ru(3)O](-1/0/+ 1/+ 2/+3) and to the bpy (0/-1) redox processes; also a wave is observed at 0.96 V, assigned to the Ru (+2/+ 3) pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling through the pi-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation.

Stereochemistry of cyclopentane derivatives from (2,3)J(CH) dependence on dihedral angle (theta H-C-C-X)

The (2,3)J(CH) dependence on dihedral angle (theta H-C-C-X) for cyclopentane derivatives was investigated. We observed that the combined use of experimentally obtained (2,3)J(CH) values and the theoretically determined dihedral angles between the corresponding nuclei can be used to infer the relative stereochemistry of the ring substituents in cyclopentane derivatives. There is a good correlation between the magnitude of (3)J(CH) and the dihedral angle between the hydrogen and the coupled carbon (R-2 = 0.88). Copyright (C) 2008 John Wiley & Sons, Ltd.

A inform??tica de ???p??s no ch??o???: um suporte ?? reforma agr??ria

Fazia algum tempo que o Incra via, na informatiza????o, um instrumento eficiente e eficaz para a obten????o do seu prop??sito final. Al??m disso, a Divis??o de Recursos Humanos da Superintend??ncia Regional do Incra no Acre enxergava, na informatiza????o, a oportunidade de melhorar o atendimento ao p??blico interno e externo da institui????o. Entretanto, entre os diversos obst??culos ?? generaliza????o do uso dos recursos de microinform??tica na institui????o, destacavam-se o alto custo e o tempo dispendido para o treinamento dos servidores.Para solucionar o problema, a Superintend??ncia Regional do Incra no Acre montou, em suas pr??prias instala????es, um Centro de Treinamento de Inform??tica. A iniciativa resultou no treinamento de 115 servidores no per??odo de um ano, com uma economia de custos financeiros de mais de 400%, elevado aproveitamento entre servidores que nunca tinham tido contato com computadores, surgimento de pelo menos treze novos treinadores entre os servidores, elabora????o de novas t??cnicas, que s??o incorporadas ao cotidiano de atividades do Incra, contribuindo para um padr??o de trabalho cada vez mais preciso e amplia????o do acesso ao treinamento em microinform??tica aos servidores de outros ??rg??os p??blicos na regi??o