Comparison of non-Ohmic accelerated ageing of the ZnO- and SnO2-based voltage dependent resistors

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

Analysis of biological tissues in infant chest for the development of an equivalent radiographic phantom

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

Importance of sperm genotype (indicus versus taurus) for fertility and embryonic development at elevated temperatures

Heat stress has negative effects on bovine reproduction, particularly for European breeds (Bos taurus taurus) that are less thermotolerant than zebu cattle (Bos taurus indicus). Here, the evidence that spermatozoa and oocyte both contribute to early embryonic resistance to heat shock is demonstrated. In addition, the use of reproductive biotechnologies to improve bovine thermotolerance, are outlined by comparing data from taurus, indicus and crossbred genotypes. (c) 2005 Published by Elsevier B.V.

Digestibility of feeds containing sorghum, with and without tannin, for broiler chickens submitted to three room temperatures

The traditional method of total excreta collection was applied, using 30 to 40 day old male Ross 308 broiler chickens. One hundred and eight broiler chickens were used, randomly assigned to a 3x3 factorial experimental design. The room temperatures were 14 C (cold), 25 °C (thermoneutral) and 32 °C (hot) and the three diets were 100% maize, 100% sorghum with tannin and 100% sorghum without tannin, with four replicates of each. The digestibility coefficients for the dry matter, crude protein, crude fibre, neutral detergent fibre, acid detergent fibre, ether extract, mineral matter and nitrogen-free extract were determined. It was observed that all the digestibility coefficients were higher in the hot chamber and lower in the cold chamber, and that these values tended to be higher for maize.

Effects of dietary trace mineral sources and levels fed to layers in their second laying cycle on the quality of eggs stored at different temperatures and for different periods

This study aimed at evaluating the effects of trace mineral levels and sources supplemented to diets fed to semi-heavy layers in their second laying cycle on the quality of eggs stored for 14 days at different temperatures. The experimental diets consisted of the inclusion of inorganic trace minerals (T1 - control: 100% ITM) and five supplementation levels of organic trace minerals (carboaminophopho chelates) (110, 100, 90, 80, and 70% OTM). Trace mineral inclusion levels (mg/kg feed) were: T1: control - 100% ITM: Zn (54), Fe (54), Mn (72), Cu (10), I (0.61) Se (0.3); T2 - 110% OTM: Zn (59.4), Fe (59.4), Mn (79.2), Cu (11.88), I (1.21) Se (0.59); T3 - 100%: OTM: Zn (54), Fe (54), Mn (72), Cu (10.8), I (1.10) Se (0.54); T4 - 90% OTM: Zn (48.6), Fe (48.6), Mn (64.8), Cu (9.72), I (0.99) Se (0.49); T5 - 80% OTM: Zn (43.2), Fe (43.2), Mn (57.6), Cu (8.64), I (0.88), Se (0.43); T6 - 70% OTM: Zn (37.8), Fe (37.8), Mn (50.4), Cu (7.56), I (0.77) Se (0.38). A completely randomized experimental design in a split-plot arrangement with 60 treatments of four replicates each was applied. The combination of six diets versus storage temperature (room or under refrigeration) was randomized in plots, whereas the sub-plots consisted of storage times (0, 3, 7, 10, and 14 days). Data were submitted to analysis of variance of a model in slip-plots in time using the software package SAS (2000) at 5% probability level. It was concluded that 70% OTM supplementation can be used with no damage to egg quality, independently from storage temperature or time. The quality of refrigerated eggs stored up to 14 days is better than those stored at room temperature.

Evaluation of Cu, Mn, and Se in Vegetables Using Ultrasonic Extraction and GFAAS Quantification

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

Population dynamics of Musca domestica (Diptera: Muscidae): experimental and theoretical studies at different temperatures

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

Subterranean termites (Isoptera: Rhinotermitidae): Exploitation of equivalent food resources with different forms of placement

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

Population dynamics of Chrysomya megacephala (Diptera : Calliphoridae) at different temperatures

In this study we analysed the theoretical population dynamics of C. megacephala, an exotic blowfly, kept at 25 and 30degreesC, using a density-dependent mathematical model, with parametric estimates of survival and fecundity in the laboratory. No change in terms of oscillation patterns was found for the two temperatures. The populations exhibited a two-point limit cycle, i.e. oscillations between two fixed points, at 25 and 30degreesC. However a quantitative change was observed, indicating that at 25degreesC the number of immatures in equilibrium is 1176 and at 30degreesC, 1944. The implications of this difference in terms of equilibrium for population dynamics of C. megacephala are discussed.

Gas exchange and ventilation during dormancy in the tegu lizard Tupinambis merianae

The tegu lizard Tupinambis merianae exhibits an episodic ventilatory pattern when dormant at 17 degrees C but a uniform ventilatory pattern when dormant at 25 degrees C. At 17 degrees C, ventilatory episodes were composed of 1-22 breaths interspaced by non-ventilatory periods lasting 1.8-26min, Dormancy at the higher body temperature was accompanied by higher rates of O-2 consumption and ventilation. The increase in ventilation was due only to increases in breathing frequency with no change observed in tidal volume. The air convection requirement for O-2 did not differ at the two body temperatures. The respiratory quotient was 0.8 at 17 degrees C and 1.0 at 25 degrees C. We found no consistent relationship between expired gas composition and the start/end of the ventilatory period during episodic breathing at 17 degrees C. However, following non-ventilatory periods of increasing duration, there was an increase in the pulmonary O-2 extraction that was not coupled to an equivalent increase in elimination of CO2 from the lungs. None of the changes in the variables studied could alone explain the initiation/termination of episodic ventilation in the tegus, suggesting that breathing episodes are shaped by a complex interaction between many variables. The estimated oxidative cost of breathing in dormant tegus at 17 degrees C was equivalent to 52.3% of the total metabolic rate, indicating that breathing is the most costly activity during dormancy.

Teleparallel equivalent of non-Abelian Kaluza-Klein theory

Based on the equivalence between a gauge theory for the translation group and general relativity, a teleparallel version of the non-Abelian Kaluza-Klein theory is constructed. In this theory, only the fiber-space turns out to be higher dimensional, spacetime being kept always four dimensional. The resulting model is a gauge theory that unifies, in the Kaluza-Klein sense, gravitational and gauge fields. In contrast with the ordinary Kaluza-Klein models, this theory defines a natural length scale for the compact submanifold of the fiber space, which is shown to be of the order of the Planck length.

Intersubband plasmon-phonon modes in quantum wires at high temperatures

Coupled intersubband plasmon-phonon modes are studied in a multisubband parabolic quantum wire at room temperatures. These modes are found by calculating the spectral weight function which is related to the inelastic Raman spectra. We use a 13 subband model. The plasmon-phonon coupling strongly modifies the dispersion relation of the intersubband modes in the vicinity of the optical phonon frequency omega(LO). Extra modes show up as a result of the electron-phonon interaction. We carefully study the density and temperature dependence of these extra modes. We also show that coupled intersubband plasmon-phonon modes should be observed for temperatures as high as 300 K.

Three-boson recombination at ultralow temperatures

The effects of trimer continuum resonances are considered in the three-body recombination rate of a Bose system at finite energies for large and negative two-body scattering lengths (a). The thermal average of the rate allows to apply our formula to Bose gases at ultra-low temperatures. We found a good quantitative description of the experimental three-body recombination length of cesium atoms to deeply bound molecules up to 500 nK. Consistent with the experimental data, the increase of the temperature moves the resonance peak of the three-body recombination rate to lower values of vertical bar a vertical bar exhibiting a saturation behavior. (C) 2006 Elsevier B.V. All rights reserved.

Screened potential and quarkonia properties at high temperatures

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Extension of the Nambu-Jona-Lasinio model predictions at high densities and temperatures using an implicit regularization scheme

Traditional cutoff regularization schemes of the Nambu-Jona-Lasinio model limit the applicability of the model to energy-momentum scales much below the value of the regularizing cutoff. In particular, the model cannot be used to study quark matter with Fermi momenta larger than the cutoff. In the present work, an extension of the model to high temperatures and densities recently proposed by Casalbuoni, Gatto, Nardulli, and Ruggieri is used in connection with an implicit regularization scheme. This is done by making use of scaling relations of the divergent one-loop integrals that relate these integrals at different energy-momentum scales. Fixing the pion decay constant at the chiral symmetry breaking scale in the vacuum, the scaling relations predict a running coupling constant that decreases as the regularization scale increases, implementing in a schematic way the property of asymptotic freedom of quantum chromodynamics. If the regularization scale is allowed to increase with density and temperature, the coupling will decrease with density and temperature, extending in this way the applicability of the model to high densities and temperatures. These results are obtained without specifying an explicit regularization. As an illustration of the formalism, numerical results are obtained for the finite density and finite temperature quark condensate and applied to the problem of color superconductivity at high quark densities and finite temperature.