The X-C center dot center dot center dot pi (X = F, Cl, Br, CN) Carbon Bond

High-level ab initio calculations have been used to study the interactions between the CH3 group of CH3X (X = F, Cl, Br, CN) molecules and pi-electrons. These interactions are important because of the abundance of both the CH3 groups and pi-electrons in biological systems. Complexes between C2H4/C2H2 and CH3X molecules have been used as model systems. Various theoretical methods such as atoms in molecules theory, reduced density gradient analysis, and natural bond orbital analysis have been used to discern these interactions. These analyses show that the interaction of the p-electrons with the CH3X molecules leads to the formation of X-C...p carbon bonds. Similar complexes with other tetrel molecules, SiH3X and GeH3X, have also been considered.

Three centered hydrogen bonds of the type C=O...H(N)...X-C in diphenyloxamide derivatives involving halogens and a rotating CF3 group: NMR, QTAIM, NCI and NBO studies

The existence of three centered C=O...H(N)...X-C hydrogen bonds (H-bonds) involving organic fluorine and other halogens in diphenyloxamide derivatives has been explored by NMR spectroscopy and quantum theoretical studies. The three centered H-bond with the participation of a rotating CF3 group and the F...H-N intramolecular hydrogen bonds, a rare observation of its kind in organofluorine compounds, has been detected. It is also unambiguously established by a number of one and two dimensional NMR experiments, such as temperature perturbation, solvent titration, N-15-H-1 HSQC, and F-19-H-1 HOESY, and is also confirmed by theoretical calculations, such as quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) and non-covalent interaction (NCI).

Role of synergistic pi-pi stacking and X-H center dot center dot center dot Cl (X = C, N, O) H-bonding interactions in gelation and gel phase crystallization

The self-assembly of p-pyridyl-ended oligo-p-phenylenevinylenes (OPVs) in ethanol leads to the formation of either hollow or solid microrods. The corresponding protonated OPVs with n-butyl chains induce transparent gelation and also gel phase crystallization owing to various synergistic noncovalent interactions. The chloride ion-selective gelation, AIEE and stimuli responsiveness of the gel are also observed.

The X-C---Y (X = O/F, Y = O, S, F, Cl, Br, N, P,) Carbon bond and hydrophobic interactions

While the tetrahedral face of methane has an electron rich centre and can act as a hydrogen bond acceptor, substitution of one of its hydrogens with some electron withdrawing group (such as -F/OH) can make the opposite face electron deficient. Electrostatic potential calculations confirm this and high level quantum calculations show interactions between the positive face of methanol/methyl fluoride and electron rich centers of other molecules such as H2O. Analysis of the wave functions of atoms in molecules shows the presence of an unusual C···Y interaction, which could be called 'carbon bonding'. NBO analysis and vibrational frequency shifts confirm the presence of this interaction. Given the properties of alkyl groups bonded to electronegative elements in biological molecules, such interactions could play a significant role, which is yet to be recognized. This and similar interactions could give an enthalpic contribution to what is called the 'hydrophobic interactions'.

Effect of the catalyst composition in the Pt-x(Ru-Ir)(1-x)/C system on the electro-oxidation of methanol in acid media

The effect of variations in the composition for ternary catalysts of the type Pt-x(Ru-Ir)(1-x)/C on the methanol oxidation reaction in acid media for x values of 0.25, 0.50 and 0.75 is reported. The catalysts were prepared by the sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analyses. The nanometric character (2.8-3.2 nm) of the sol-gel deposits was demonstrated by XRD and TEM while EDX and AAS analyses showed that the metallic ratio in the compounds was very near to the expected one. Cyclic voltammograms for methanol oxidation revealed that the reaction onset occur at less positive potentials in all the ternary catalysts tested here when compared to a Pt-0.75-Ru-0.25/C (E-Tek) commercial composite. Steady-state polarization experiments (Tafel plots) showed that the Pt-0.25(Ru-Ir)(0.75)/C catalyst is the more active one for methanol oxidation as revealed by the shift of the reaction onset towards lower potentials. In addition, constant potential electrolyses suggest that the addition of Ru and Ir to Pt decreases the poisoning effect of the strongly adsorbed species generated during methanol oxidation. Consequently, the Pt-0.25 (Ru-Ir)(0.75)/C Composite catalyst is a very promising one for practical applications. (c) 2007 Elsevier B.V. All rights reserved.

Eficácia de uma nova formulação de glifosato para o controle de grama-seda (Cynodon dactylon), em pomar de citros.

Avaliou-se a eficácia do herbicida glifosato potássico, comparado ao sulfosato e ao glifosato amínico, utilizados como padrões comerciais. Os herbicidas foram aplicados em um pomar de laranja da variedade Pêra-rio, infestado por grama-seda (Cynodon dactylon) com aproximadamente 25 cm de altura, em 70% da área. O experimento foi instalado no município de Taiúva-SP, em solo Podzólico Vermelho-Amarelo, distrófico, de textura arenosa, com relevo suave ondulado. Os tratamentos testados foram: glifosato potássico (ZAPP Qi) a 1,05; 2,10 e 2,50 kg e.a./ha, sulfosato (ZAPP) e glifosato amínico (ROUNDUP CS) a 1,98 e 2,16 kg e.a./ha, respectivamente, além da testemunha sem capina. Os herbicidas foram aplicados em pós-emergência da planta daninha, com pulverizador costal, à pressão constante (mantida por CO2 comprimido) de 2,5 kg/cm², munido de barra com seis bicos de jato plano (leque) DG 11002, com um consumo de calda equivalente a 200 L/ha. Os melhores resultados de controle foram obtidos com 2,5 kg e.a./ha do glifosato potássico, que também garantiu menor brotação da grama-seda. No entanto, a dosagem de 2,10 kg e.a./ha deste mesmo herbicida não foi menos eficaz que o sulfosato e o glifosato, com 1,98 e 2,16 kg e.a./ha, respectivamente.

Boundary of the rauzy fractal sets in R x C generated by P(x)=x(4)-x(3)-x(2)-x-1

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desempenho de bezerros da raça Nelore e cruzados desmamados recebendo concentrado em pastagem adubada de Cynodon dactylon cv. Coastcross

Em três anos de pesquisa, avaliou-se o desempenho de bezerros desmamados de quatro grupos genéticos (Nelore; Canchim × Nelore; Angus × Nelore; e Simental × Nelore) em pastagem de Cynodon dactylon, cv. Coastcross, adubada, sob manejo rotacionado, recebendo mistura mineral ou concentrado. O concentrado foi fornecido na quantidade de 3 kg/animal/dia e continha 18,8% de proteína bruta e 81,5% de nutrientes digestíveis totais na matéria seca. A quantidade de forragem disponível diferiu com a utilização de mistura mineral e concentrado (2.961 kg e 3.383 kg de matéria seca (MS) por hectare, respectivamente). A oferta de MS/animal/dia foi 9,9 kg/dia (3,9% PV) para mistura mineral e 9,0 kg/dia (3,3% PV) para concentrado. A forragem disponível possuía, na matéria seca, 13,6% de proteína bruta, 79,8% de fibra em detergente neutro; 62,3% de digestibilidade in vitro da matéria seca, 3,9 g/kg de cálcio, 2,0 g/kg magnésio, 2,5 g/kg de fósforo, 22,7 g/kg de potássio, 2,8 g/kg de enxofre, 9,9 mg/kg de cobre, 22,5 mg/kg de zinco, 98 mg/kg de manganês e 188 mg/kg de ferro. Foram observadas interações grupo genético × suplementação e ano × suplementação para ganho diário de peso e taxa de lotação das pastagens e ciclo de pastejo × suplementação para a taxa de lotação. O ganho diário de peso nos animais Nelore, Canchim × Nelore, Angus × Nelore e Simental × Nelore criados com suplementação do pasto com mistura mineral foi de 0,48; 0,63; 0,68 e 0,50 kg, enquanto naqueles que receberam concentrado foi de 0,87; 0,95; 0,99 e 0,95 kg, respectivamente. As médias estimadas das taxas de lotação das pastagens foram 6,1 para todos os grupos genéticos que receberam mistura mineral e 7,5; 7,6; 8,8 e 9,0 unidades animais/ha para os grupos genéticos Nelore, Canchim × Nelore, Angus × Nelore e Simental × Nelore que receberam concentrado, respectivamente. O grupo genético influencia o desempenho de bovinos em pastagem de capim-coastcross e interage com a suplementação com concentrado.

Efeitos da amonização sobre a ocorrência de fungos, composição química e digestibilidade in vitro de fenos de grama Seda (Cynodon dactylon (L.) Pers.)

The experiment was conducted with grama seda (Cynodon dactylon (L.) Pers.) hays stored with a low moisture content (12-15%) and without chemical treatment, and hays stored with a high moisture content (20-25%) and treated with anhydrous ammonia (NH3) al 0.5 and 1.0% of DM, and urea at 0.9 and 1.8% of DM. At 65 days after treatment (AT) under a plastic cover, the bales were opened and samples were taken at 3, 15 and 30 days to determine the chemical composition and in vitro digestibility (IVDMD) of the hays. For the identification of fungi, samples were taken at 0, 15 and 30 days AT. The data were analyzed according to a split-plot design with the effects of the chemical treatments studied in the main plot and the effects of the periods of post-treatment studied in the sub-plots, Fourteen genera of fungi were observed in the hays, not treated and treated with NH3 and urea, with a higher occurrence of Cladosporium, Curvularia, Aspergillus, and Penicillium. Treatment with anhydrous ammonia and 1.8% urea controlled the occurrence of Aspergillus; however, Penicillium decreased in hays treated with ammonia 30 days AT. Ammoniation did not influence the contents of ADF, cellulose and lignin in the hays, but NDF and hemicellulose decreased with the use of ammonia 30 days AT. The CP contents and the IVDMD increased with ammoniation. The CP contents decreased in hays treated with NH3 as days AT increase, while hays treated with urea did not change.

Biofertilizante na produção do capim Cynodon dactylon cv. Tierra Verde: Amanda de Castro Correia. -

Pós-graduação em Ciência Animal - FMVA

Efeito da tosquia estratégica no comportamento ingestivo de ovelhas Ile de France em pastagem de capim vaquero (Cynodon dactylon cv Vaquero) durante a estação de monta

The experiment evaluated the effects of strategic shearing on feeding behavior in Ile de France ewes in Bermudagrass (Cynodon dactylon) grazing during breeding season. A total of 20 ewes, female, Ile de France breed, 4 years old, 71.10 kg of body weight, in grazing, in a completely randomized design with two treatments and ten repetitions, in which the treatments were composed by shorn and non-shorn animals. The length of the breeding season was 90 days, where the evaluations occurred in the 86th, 87th and 88th day of the experimental period. The grazing time (6.50 hours), rumination (1.59 hours) and idle (3.97 hours) have not changed (P> 0.05) by strategic shearing of the animals, as well as the frequency and the time by frequency grazing (18.33 grazing and 21.49 min/grazing), rumination (10.71 ruminations and 8.83 min/rumination) and idle (18.83 idles and 12.66 min/idle). In the same way, the number of bits per minute (26.37 bits) and the total daily bits (19.116 bits) of the animals were not affected. Thus, the strategic shearing in Ile de France ewes in Bermudagrass grazing during the breeding season does not alter animal feeding behavior.

Quantum Aspects of Solitons and Deformations on Ad'S IND. 4'x C'P POT.3' ('S POT. 7')

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atributos químicos no solo e produção de Cynodon dactylon cv. Tierra Verde sob doses de biofertilizante orgânico

The concentration of nutrients in plant is related to the soil, fertilization, climate, season, cultivar and cultural practices. Aiming to evaluate the soil chemical properties, the dry matter production of shoots and roots, nutrient content in the plant and the chemical composition of the grass Tierra Verde subjected to levels of organic biofertilizer as nitrogen source, an experiment was conducted in a greenhouse at the Faculty of Veterinary Medicine , UNESP, Araçatuba-SP, January-September 2010. Treatments were arranged in a completely randomized design with six fertilized biofertilizer doses (0, 33, 66, 132, 264, 528 m3 ha-1) and five repetitions for three cuts. We used the model split plot, with doses of biofertilizer considered as main treatments and cuts as sub-plots. We obtained a linear response in the production of dry mass of shoots and roots to the dose of 528 m3 ha-1 of organic biofertilizer. Nitrogen fertilization influenced the soil chemical properties and levels of organic matter, sulfur, boron and manganese, and in foliar levels of phosphorus, potassium and copper. The chemical composition was not altered by the influence of organic biofertilizer doses applied to the soil.

Desenvolvimento de grama-esmeralda, grama-bermudas 'Tifway 419' e 'Celebration' submetidas a aplicação de reguladores de crescimento

Pós-graduação em Agronomia (Produção Vegetal) - FCAV