Recovery of a marker strain of Salmonella typhimurium in litter and aerosols from isolation rooms containing infected chickens

Screening of poultry flocks for foodborne pathogen Salmonella contamination is critical for Salmonella control in preharvest stages of poultry production. In this study, two sampling methods (litter and air filter) were compared for detection of S. typhimurium from experimentally infected chicks some of which had received either a probiotic competitive exclusion culture or transfer of cecal contents from salmonellae-free adult birds. At 4, 9, and 11 days after inoculation, S. typhimurium samples were enumerated by selective plating. For both types of sampling, the control birds yielded the greatest levels of environmental contamination followed by the samples from the probiotic inoculated birds with the birds receiving the cecal transfer culture having the lowest levels of contamination. Although the two sampling methods responded in a similar fashion, detection sensitivity needs to be increased for air filter sampling.     

Do we need to examine the quantitative data obtained from toxicity studies for both normality and homogeneity of variance?

Most of the statistical techniques used to evaluate the data obtained from toxicity studies are based on the assumption that the data show a normal distribution and homogeneity of variance. Literature review on toxicity studies on laboratory animals reveals that in most of the cases homogeneity of variance alone is examined for the data obtained from these studies. But the data that show homogeneity of variance need not always show a normal distribution. In fact, most of the data derived from toxicity studies, including hematological and biochemical parameters show a non-normal distribution. On examining normality of data obtained from various toxicity studies using different normality tests, we observed that Shapiro-Wilk test is more appropriate than Kolmogorov-Smimov test, Lilliefors test, the normal probability paper analysis and Chi square test. But there are situations, especially in the long-term toxicity studies, where normality is not shown by one or more than one of the dosage groups. In this situation, we propose that the data maybe analyzed using Dunnett multiple comparison test after excluding the data of the groups that do not show normality However, the biological relevance of the excluded data has to be carefully scrutinized. We also observed that the tendency of the data to show a normal distribution seems to be related to the age of the animals. Present paper describes various tests commonly used to test normality and their power, and also emphasizes the need of subjecting the data obtained from toxicity studies to both normality and homogeneity tests. A flow chart suggesting the statistical techniques that maybe used for both the types of data showing a normal or non-normal distribution is also proposed.     

Seasonal variation in male-female competition,cooperation and selfish hoarding in a monogamous songbird

Both cooperation and conflict between the sexes are commonplace in monogamous mating systems. However, little is known about how cooperation and competition varies seasonally in monogamous species that maintain permanent territories. We presented territorial pairs of male and female New Zealand robins (Petroica australis) with a large supply of insect prey at monthly intervals for 2 years. Behavioural observations after food presentation were then made to quantify seasonal and sexual differences in aggressive interactions over prey, prey acquisition rates, mate provisioning, offspring provisioning, selfish food hoarding and cache retrieval. Data were used to evaluate sex-specific behavioural strategies of mediating competition for food. Results showed that males aggressively excluded females from experimental food sources year-round. Females only accessed food sources when males left them unattended. Consequently, females acquired fewer prey than males. After controlling for differences in prey acquisition, both sexes consumed similar amounts of prey in the non-breeding season. Even though males aggressively excluded females from accessing food sources directly, males fed large amounts of prey to females during the breeding season. Both sexes provisioned young at similar rates. Males cached less prey than females in the breeding season but more prey than females in the non-breeding season. Females showed similar caching intensities year-round. Although males tried to defend their hoards, females frequently retrieved male-made caches. Overall, results showed that although New Zealand robins cooperate to raise offspring during the breeding season, conflict between the sexes occurs year-round. Males and females display different behavioural strategies to gain access to experimental food sources, which appear to lessen male–female competition for food and evenly distribute food resources between the sexes.     

Soil-catalyzed oxidation of aniline

Aniline partially degraded in sterile soil to azobenzene, azoxybenzene, phenazine, form=anilide, and acetanilide. Nitrobenzene, $\text{p}$-benzoquinone, and unidentified species were possible products; substantial bound residues may also have formed. Soil-catalyzed conversion of aniline or [$\text{d}$₅]aniline seems evidenced by 6-24X more product recovery in sterile soil than in sterile water alone, a process inhibited by Na₂S₂O₄. Freundlich adsorption constants showed: azobenzene > azoxybenzene > phenazine > aniline.     

Studies on electrochemical recovery of silver from simulated waste water from Ag(II)/Ag(I) based mediated electrochemical oxidation process

In the Ag(II)/Ag(I) based mediated electrochemical oxidation (MEO) process, the spent waste from the electrochemical cell, which is integrated with the scrubber columns, contains high concentrations of precious silver as dissolved ions in both the anolyte and the catholyte. This work presents an electrochemical developmental study for the recovery of silver from simulated waste water from Ag(II)/Ag(I) based MEO process. Galvanostatic method of silver deposition on Ti cathode in an undivided cell was used, and the silver recovery rate kinetics of silver deposition was followed. Various experimental parameters, which have a direct bearing on the metal recovery efficiency, were optimized. These included studies with the nitric acid concentration (0.75-6M), the solution stirring rate (0-1400 rpm), the inter-electrode distance between the anode and the cathode (2-8 cm), the applied current density (29.4-88.2 mA cm(-2)), and the initial Ag(I) ion concentration (0.01-0.2M). The silver recovered by the present electrodeposition method was re-dissolved in 6M nitric acid and subjected to electrooxidation of Ag(I) to Ag(II) to ascertain its activity towards Ag(II) electrogeneration from Ag(I), which is a key factor for the efficient working of MEO process. Our studies showed that the silver metal recovered by the present electrochemical deposition method could be reused repeatedly for MEO process with no loss in its electrochemical activity. Some work on silver deposition from sulfuric acid solution of different concentrations was also done because of its promising features as the catholyte in the Ag(II) generating electrochemical cell used in MEO process, which include: (i) complete elimination of poisonous NO(x) gas liberation in the cathode compartment, (ii) reduced Ag(+) ion migration across Nafion membrane from anolyte to catholyte thereby diminished catholyte contamination, and (iii) lower cell voltage and hence lesser power consumption.     

Bioaerosols from land-applied biosolids: issues and needs.

Bioaerosols are a vehicle for the dissemination of human and animal pathogens. Because of land-filling costs and the ban on ocean dumping of municipal biosolids, land application of biosolids and animal manure is increasing all over the globe. There is no doubt that the creation, generation, and disposal of human and animal wastes increases the aerosolization potential of a wide variety of microbial pathogens and related pollutants. In an attempt to address public health issues associated with the land application of municipal biosolids, the U.S. National Research Council (Washington, D.C.) published a report on this issue in 2002. This paper focuses on the current information and technology gaps related to estimating the public health risks associated with bioaerosols during the land application of biosolids.     

Retarding fluoride accumulation in Amaranthes viridis through liming and implications of phosphorous treatment

With an objective to retard fluoride being taken up by the plants from soil, a study was carried out on Amaranthes viridis. Four groups of treatment were carried out vis-à-vis fluoride alone, fluoride and calcium, fluoride and phosphorous and fluoride, calcium and phosphorous together at three different concentration levels vis-à-vis 1, 10 and 25 mg/kg soil of each. Sampling was carried out first on day 45 and at the end of reproductive phase on leaf and seed for accumulation of fluoride in the plants. It was observed that fluoride accumulation in plants could be averted through soil amendment by calcium treatment in the form of calcium carbonate thereby reducing the risk of human and livestock exposure to abnormal levels of fluoride through food chain other than protecting plants from getting affected. At the same time, fertilizing the soil contaminated with fluoride by superphosphate would aggravate fluoride accumulation and exacerbate fluorosis problem in human and livestock through food chain. Therefore it is recommended to use acid water-soluble orthophosphate or anhydrous dicalcium phosphate or soluble pyrophosphate fertilizers as an alternative.     

Statistical tools for analysing the data obtained from repeated dose toxicity studies with rodents: a comparison of the statistical tools used in Japan with that of used in other countries

In the present study, an attempt was made to compare the statistical tools used for analysing the data of repeated dose toxicity studies with rodents conducted in 45 countries, with that of Japan. The study revealed that there was no congruence among the countries in the use of statistical tools for analysing the data obtained from the above studies. For example, to analyse the data obtained from repeated dose toxicity studies with rodents, Scheffé's multiple range and Dunnett type (joint type Dunnett) tests are commonly used in Japan, but in other countries use of these statistical tools is not so common. However, statistical techniques used for testing the above data for homogeneity of variance and inter-group comparisons do not differ much between Japan and other countries. In Japan, the data are generally not tested for normality and the same is true with the most of the countries investigated. In the present investigation, out of 127 studies examined, data of only 6 studies were analysed for both homogeneity of variance and normal distribution. For examining homogeneity of variance, we propose Levene's test, since the commonly used Bartlett's test may show heterogeneity in variance in all the groups, if a slight heterogeneity in variance is seen any one of the groups. We suggest the data may be examined for both homogeneity of variance and normal distribution. For the data of the groups that do not show heterogeneity of variance, to find the significant difference among the groups, we recommend Dunnett's test, and for those show heterogeneity of variance, we recommend Steel's test.     

Proposed city-specific interim targets for India based on WHO air quality guidelines 2021

Environmental Science and Pollution Research - The World Health Organization has proposed the ambient air quality guidelines 2021. The uniqueness of the guidelines of the World Health Organization...