Prevention and control of contaminants of industrial processes and pesticides in the poultry production chain

The reduction in levels of organochlorine pesticide residues in food of animal origin in the past 30 years has been achieved especially by controlling entrance via the feed chain. A further reduction was achieved by registration and use of less persistent pesticides both for direct treatment of animals and of plant material. The remaining problems (e.g. dioxins and PCB's) are much harder to tackle. They are either of a ubiquitous nature and their impact might be enlarged by the present welfare trend requiring more contact of the animals with their environment, or they are of a sporadic nature making checking and control quite hard to execute. The present public demand for a farm animal production that is in balance with the animals' needs and a residue free product adds even more complications to the system

A general learning algorithm for solving optimization problems and its application to the spin glass problem

We propose a general learning algorithm for solving optimization problems, based on a simple strategy of trial and adaptation. The algorithm maintains a probability distribution of possible solutions (configurations), which is updated continuously in the learning process. As the probability distribution evolves, better and better solutions are shown to emerge. The performance of the algorithm is illustrated by the application to the problem of finding the ground state of the Ising spin glass. A simple theoretical understanding of the algorithm is also presented.Comment: 9 pages, 3 figure

Students' perceptions of learning through assessment for learning and technology.

This study investigates the implementation of the concept of assessment for learning in the context of computer education courses in teacher education in Macau. It aims to promote reflection in students' learning with the use of technology. The concept of assessment for learning was infused into the courses taught by the researcher. Opportunities for self-assessment, peer-assessment and constructive feedback were set up for students to examine their own learning through the online technoiogy, of blogging and digital portfolios. One hundred and seventeen teachers and teacher candidates, taking Computer, Applications, Educational Technology and Information Technology in Education experienced a curriculum based on the concept of assessment for learning for a period of thirteen to fourteen weeks. Nineteen of them experienced a longer period of about twenty-seven weeks. Students were requested to reflect on the course content weekly using blogs and the journal content of the blogs serves as the main source for data analysis. In addition, a questionnaire was given to students to seek their v'iew on the use of blogs for reflection and communication purposes. Analysis of data from different sources such as questionnaire, students' journals and their digital learning portfolios show that students do engage in the reflective process. However, the quality of reflection for most students was not deep. Students did make use of the journal to communicate with. the tutor. The communication pattern of students using online environment shows that they support their peers by words of encouragement, affirmation and empathy. Students value the feedback provided by both the tutor and their classmates. Major problems encountered by students are: the requirement to write a weekly journal and knowledge of what constitutes reflective journal content. The study concludes that assessment for learning is a viable approach that can be supported through blog and digital portfolios. However, the successful implementation of the assessment for learning requires the active facilitation of the tutor to engage students in the process of reflection and communication.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Residential Mobility and Social Capital

This paper empirically investigates the role of social capital in households’residential mobility behavior by considering its spatial dimension. This study focuses on a household’s social ties with people living nearby, which we refer to as its “local social capital”. Local social capital may deter residential mobility, because the resources stemming from them are location-specific and will be less valuable if a household moves. We conjecture that a household’s possession of local social capital has a negative effect on its residential mobility, and this negative effect of local social capital may be stronger on long-distance mobility than on short-distance mobility. Our empirical investigation is based on data from the Panel Study of Income Dynamics. We obtain evidence which is supportive of these conjectures.