Finite group actions on products of spheres

In this work we make some contributions to the theory of actions of finite groups on products of spheres. Suppose that the group Z(q)(tau) acts freely on the product of k copies of spheres. Question: Is r less than or equal to k? We solve this question for several values of r and k.

On the hardy space H¹ on products of half-spaces

We show that the Hardy space H¹ anal (R2+ x R2+) can be identified with the class of functions f such that f and all its double and partial Hubert transforms Hk f belong to L¹ (R2). A basic tool used in the proof is the bisubharmonicity of |F|q, where F is a vector field that satisfies a generalized conjugate system of Cauchy-Riemann type.

Release of intermediate reactive hydrogen peroxide by macrophage cells activated by natural products

By determining the hydrogen peroxide (H2O2) released in cultures of peritoneal macrophage cells from Swiss mice, we evaluated the action of 27 vegetable compounds (pristimerin, tingenone, jatrophone, palustric acid, lupeol, cladrastin, ocoteine, boldine, tomatine, yohimbine, reserpine, escopoletin, esculine, plumericin, diosgenin, deoxyschizandrin, p-arbutin, mangiferin, and others) using a 2 mg/ml solution of each compound (100 mug/well). Macrophages are cells responsible for the development of the immunological response reaction, liberating more than one hundred compounds into the extracellular environment. Among these are the various cytokines and the intermediate compounds of nitrogen (NO) and oxygen (H2O2). This coordinated sequence of biochemical reactions is known as the oxidative burst. When we compared the results with those obtained with zymosan (an important stimulator of H2O2) we observed that the compounds showing the highest activity were substances 2 (tingenone), 16 (reserpine) and 20. Other substances such as compounds 1, 4, 5, 6, 8, 12, 13, 14, 15, 17, 19, 23, 24, 26, and 27 also showed a certain activity, but with less intensity than the aforementioned ones. Compounds 3, 7, 9, 10, 11, 18, 21, 22 and 25 presented no activity. These results suggest that natural products (mainly tingenone and reserpine and others) with different chemical structures are strong immunological modulators. However, further tests are needed to determine the 'oxidative burst' in future studies.

Charqui meats as fermented meat products: role of bacteria for some sensorial properties development

Jerked beef, a derivative of charqui meat, is a cured, salted and dried meat product. The presence of halotolerant bacteria, where Staphylococcus spp. (84.2%) were the predominant species, would act eventually as starter cultures and was followed throughout processing. Jerked beef prepared separately with exogenous S. carnosus and S. xylosus as starter cultures resulted in high proteolysis. Samples prepared with S. xylosus had the highest proteolysis and were preferred by the sensory panel. This research has suggested that jerked beef (and thus charqui meat) prepared under these conditions is a fermented meat product. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

A simple prescription for computing the stress-energy tensor

A non-variational technique for computing the stress-energy tensor is presented. The prescription is used, among other things, to obtain the correct field equations for Prasanna's highly nonlinear electrodynamics.

Detection of Listeria sp in meat and meat products using TECRA Listeria visual immunoassay and biocontrol visual immunoprecipitate assay for Listeria immunoassays and a cultural procedure

The routine methods for detecting Listeria sp. in foods are time consuming and involve using selective enrichments and plating on agars. In this study, the presence of Listeria sp. in 120 meat and meat product samples was investigated by two rapid immunoassays (TECRA Listeria Visual Immunoassay [VIA] and BioControl Visual Immunoprecipitate Assay [VIP] for Listeria) and a cultural procedure. The cultural method of detecting Listeria sp. followed Canada's Health Protection Branch Method, and the rapid tests followed the manufacturers' instructions. The agreement between the cultural and the rapid tests was established at a confidence limit of 95%. Seventy-nine samples (65.8%) were Listeria sp. positive in at least one of the three tests. There was no statistically significant difference between the cultural procedure and any of the rapid immunoassays. The agreement rates between the VIA and the cultural method and between the VIP and the cultural method were 87 and 84%, respectively. Both tests - the VIA and VIP - proved to be rapid, efficient and easy to perform.

Density, heat capacity and thermal conductivity of liquid egg products

Density, heat capacity and thermal conductivity of liquid egg products, such as egg white, egg yolk, whole egg and various white and yolk blends, were determined as affected by temperature and water content ranging from 273 to 311 K and 51.8 to 88.2% (mass), respectively. Polynomial models fitted the experimental data very well, showing a linear relationship both for temperature and water content. (c) 2005 Published by Elsevier Ltd.

On the dissimilarity between the algorithms for computing the symmetric energy-momentum tensor in ordinary field theory and general relativity

The recipe used to compute the symmetric energy-momentum tensor in the framework of ordinary field theory bears little resemblance to that used in the context of general relativity, if any. We show that if one stal ts fi om the field equations instead of the Lagrangian density, one obtains a unified algorithm for computing the symmetric energy-momentum tensor in the sense that it can be used for both usual field theory and general relativity.

Predicting beef carcass retail products of Mediterranean buffaloes by real-time ultrasound measures

Twenty eight Mediterranean buffaloes bulls were scanned with real-time ultrasound (RTU), slaughtered, and fabricated into retail cuts to determine the potential for ultrasound measures to predict carcass retail yield. Ultrasound measures of fat thickness, ribeye area and rump fat thickness were recorded three to five days prior to slaughter. Carcass measurements were taken, and one side of each carcass was fabricated into retail cuts. Stepwise regression analysis was used to compare possible models for prediction of either kilograms or percent retail product from carcass mesaurements and ultrasound measures. Results indicate that possible prediction models for percent or kilograms of retail products using RTU measures were similar in their predictive power and accuracy when compared to models derived from carcass measurements. Both fat thickness and ribeye area were over-predicted when measured ultrasonically compared to measurements taken on the carcass in the cooler. The mean absolute differences for both traits are larger than the mean differences, indicating that some images were interpreted to be larger and some smaller than actual carcass measurements. Ultrasound measurements of REA and FT had positive correlations with carcass measures of the same traits (r=.96 for REA and r=.99 for FT). Standard errors of prediction currently are being used as the standard to certify ultrasound technicians for accuracy. Regression equations using live weight (LW), rib eye area (REAU) and subcutaneous fat thickness (FTU) between 12(th) and 13 (th) ribs and also over the biceps femoris muscle (FTP8) by ultrasound explained 95% of the variation in the hot carcass weight when measure immediately before slaughter.

Antibacterial properties of propolis and products containing propolis from Brazil

Crude propolis and commercial products containing propolis, such as ethanolic extracts, tablets, capsules and powders acquired in São Paulo City (Brazil) were analyzed. The resins of the solid products were extracted with ethanol and found to be present at various concentrations, independently of the propolis concentration specified on the label of the commercial products. The in vitro activity of these resins against S aureus, B cereus and B subrilis was also determined. The results showed that the antibacterial activity rather than the propolis concentration itself should be considered for quality control and that some resins are likely to display a species-specific action.

VACUUM POLARIZATION TENSOR IN 3-DIMENSIONAL QUANTUM ELECTRODYNAMICS

We evaluate the one-loop vacuum polarization tensor for three-dimensional quantum electrodynamics (QED), using an analytic regularization technique, implemented in a gauge-invariant way. We show thus that a gauge boson mass is generated at this level of radiative correction to the photon propagator. We also point out in our conclusions that the generalization for the non Abelian case is straightforward.

Assessment of the application of cathodic stripping voltammetry to the analysis of diazo reactive dyes and their hydrolysis products

Two reactive dyes, C.I. Reactive Red 120 (RR120) and C.I. Reactive Green 19 (RG19), each bearing two azo groups as the chromophoric moiety and two monochloro-s-triazine groups as reactive groups, can be detected at nanomolar levels using cathodic stripping voltammetry. Linear calibration graphs were obtained for both reactive dyes, from 0.015 to 0.14 mu mol l(-1) for RR120 in pH 4 buffer and from 0.012 to 0.26 mu mol l(-1) for RG19 in pH 3 buffer, using a preconcentration at 0 V during 180 and 240 s on the mercury electrode, respectively. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Mutagenic activity in waste from an aluminum products factory in Salmonella/microsome assay

The mutagenic activity of waste material originating from an aluminum products factory was determined by the Salmonella/microsome assay, using the bacterial strains TA100, TA98 and YG1024. The material was obtained by sweeping the factory floor at the end of the work shift. Organic compounds were extracted by ultrasound for 30 min in dichloromethane or 70% ethanol. After evaporation of solvent, these extracts were dissolved in dimethylsulfoxide, and tested for the mutagenic activity at varying concentrations. All the extracts from the factory had mutagenic activity, especially in the YG1024 strain, suggesting the presence of aromatic amines, later confirmed by chemical analysis. The TA98 strain also showed mutagenic activity, though it did not exhibit the highest mutagenicity index observed with the YG1024 strain. In TA100, mutagenic activity was not observed. This study should serve as an alert to management and those who are occupationally exposed, and as a warning that this type of waste should not be discarded in the environment without any control. (C) 2004 Elsevier Ltd. All rights reserved.