Age- and sex-dependent distribution of persistent organochlorine pollutants in urban foxes

The colonization of urban and suburban habitats by red foxes (Vulpes vulpes) provides a novel sentinel species to monitor the spread of anthropogenic pollutants in densely populated human settlements. Here, red foxes were collected in the municipal territory of Zürich, Switzerland, and their perirenal adipose tissue was examined for persistent organochlorine residues. This pilot study revealed an unexpected pattern of contamination by polychlorinated biphenyls (PCBs), with significantly higher levels of the predominant congeners PCB-138, PCB-153, and PCB-180 in juvenile foxes relative to adult animals. Further data analysis demonstrated that the observed difference was attributable to an age-dependent reduction of PCB concentrations in females, whereas male foxes retained approximately the same PCB burden throughout their life span. A similar sex-related bias between population members has been observed, primarily in marine mammals. Interestingly, the reduction of organochlorine contents with progressive age is reminiscent of human studies, where an extensive maternal transfer of xenobiotics to the offspring has been shown to result in increased exposure levels of infants relative to adults. To our knowledge, this is the first example of an urban wildlife species that faithfully reflects the dynamic distribution of toxic contaminants in the corresponding human population. Suburban and urban foxes occupy habitats in close proximity to humans, depend on anthropogenic food supplies, are relatively long-lived and readily available for sampling, can be easily aged and sexed, have a limited home range, and, therefore, meet several important requirements to serve as a surrogate species for the assessment of toxic health hazards

Influência da soma térmica e da chuva durante o desenvolvimento de laranjas-'Valência' e 'Natal' na relação entre sólidos solúveis e acidez e no índice tecnológico do suco Influence of the accumulated heat unit and rainfall on the ratio and technological index of sweet oranges 'Valência' and 'Natal'

Este trabalho foi realizado com o objetivo de conhecer a influência que algumas variáveis meteorológicas exercem na razão entre sólidos solúveis totais e acidez total titulável ("ratio") e no índice tecnológico dos frutos da primeira florada das laranjeiras-'Natal' e 'Valência', na região de Bebedouro-SP, mediante a utilização de métodos estatísticos de regressão. Foram utilizados dados de amostragens de rotina para o processamento industrial durante 4 anos, os quais permitiram desenvolver equações de regressão linear e quadrática, com a soma térmica (graus-dia) como variável independente, e de regressão múltipla, utilizando graus-dia e chuva como variáveis independentes. A equação de melhor ajuste para o índice tecnológico foi a quadrática, enquanto para o "ratio" a equação linear apresentou o melhor ajuste. A temperatura do ar, representada por graus-dia, foi a variável que exerceu maior influência nos indicadores de qualidade dos frutos.<br>This study aimed to know the influence of some meteorological variables on the ratio and technological index for oranges provided from 'Natal' and 'Valencia' orchards, from field plots, located at Bebedouro - São Paulo - Brazil. The quality indicators, ratio and technological index, were obtained from routine processing plant tests. These parameters were related to the meteorological variables: degree-day and rainfall. In order to determine which independent variable had a stronger influence on the fruit quality indicators, single and multiple linear regressions analysis were applied. The results have shown that technological index is better described by a quadratic function, and ratio is better described by a linear regression, as function of independent variables. The statistical analysis have indicated that the air temperature, expressed by accumulated degree day, is the meteorological aspect that had greater influence in fruit quality indicators

Investigation of photochemical paths by a combined theoretical and experimental approach.

Investigation of photochemical paths in condensed phases by a combined theoretical and experimental approac