Highly virulent pathogens that cause host population declines confront the risk of fade-out, but if pathogen transmission dynamics are age-structured, pathogens can persist. Among other features of amphibian biology, variable larval developmental rates generate age-structured larval populations, which in theory can facilitate pathogen persistence. We investigated this possibility empirically in...

Game animals, such as the roe deer (Capreolus capreolus), have long been used as bioindicators of environmental contamination. Most ecotoxicological research on ungulates has focused on trace element content in soft tissues and antlers. Also, only fragmentary information exists about whether and how trace element concentrations vary with the age of wild-living animals and whether these age-rela...

(co) variance components and genetic parameters for growth traits in arman sheep were estimated, using data collected during an 11-year period (1999-2010), by applying the restricted maximum likelihood (reml) procedure under univariate and bivariate animal models. the studied traits were body weight of lamb at birth (bw), body weight at 3 months of age as weaning weight (ww), body weight at 6 m...

Article history: Received 21 January 2008 Received in revised form 12 September 2008 Accepted 10 November 2008 In this study a total of 6499 records were obtained for fibre diameter (FD) and coefficient of variation of FD (CV), 3283 records for greasy fleece weight (GFW), staple length (SL) and shearing interval (SI) and 1802 records of textile value index (TV) obtained from an experimental her...

We quantified the potential increase in accuracy of expected breeding value for weights of Nelore cattle, from birth to mature age, using multi-trait and random regression models on Legendre polynomials and B-spline functions. A total of 87,712 weight records from 8144 females were used, recorded every three months from birth to mature age from the Nelore Brazil Program. For random regression a...

The test-day yields of milk, fat and protein were analysed from 1433 first lactations of buffaloes of the Murrah breed, daughters of 113 sires from 12 herds in the state of São Paulo, Brazil, born between 1985 and 2007. For the test-day yields, 10 monthly classes of lactation days were considered. The contemporary groups were defined as the herd-year-month of the test day. Random additive genet...

the environmental problems, in different dimensions, are resulted from the lack of environmental considerations and criteria in locating new cities. the main purpose of this article is to compare different criteria based on library studies and expert opinions and determining suitable criteria in order to evaluate the environmental potential to establish new cities to achieve urban permanent dev...

A catalogue record for this title is available from the British Library. The publisher's policy is to use permanent paper from mills that operate a sustainable forestry policy, and which has been manufactured from pulp processed using acid-free and elementary chlorine-free practices. Furthermore, the publisher ensures that the text paper and cover board used have met acceptable environmental ac...

Single neurons in the kitten visual cortex can be induced to increase their responsiveness to a repeated stimulus applied while the neurons are under observation. These short-term changes are in the same direction as the permanent modifications produced in whole populations of neurons following environmental manipulations during the "critical period" of cortical development, but are less pronou...