Performance assessment and teacher professional development.

This study investigates the relationship between performance assessment and teacher professional development. It explores how the process of learning to implement a novel, comprehensive assessment system contributes to the development of teachers' understandings about teaching, learning, and assessment. A staff development framework was implemented to support collegial dialogue and collaboration as teachers learned to implement the system. Interpretive methods of analysis were used to explore the teachers' understandings of the Work Sampling System (WSS), a comprehensive performance assessment for age three to grade five. Eleven teachers participated in group and individual meetings with the researcher, and used WSS materials exclusively for assessment and reporting. All meetings were audiotaped, field notes of observations were kept, and assessment materials reviewed. Methods of qualitative analysis--narrative analysis, argument analysis, conversation analysis, and thematic analysis--were employed to analyze the information, and to articulate the teachers' understandings from their perspectives. Results demonstrate that documentation and evaluation of student learning spurred teachers to reflect upon their practices, beliefs, and knowledge. Shared engagement with performance assessment facilitated professional growth. This study documents how teachers learned to use the assessment system, the range and complexity of their responses to the system, and issues that contribute to teachers' differential responses to change. Recommendations for the improvement of staff development and lasting adaptation of such major innovations as performance assessments are made.Ph.D.EducationEducational tests and measurementsTeacher educationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/130461/2/9732069.pd

Disease resistance and infectivity of virus susceptible and resistant common carp strains

Abstract Infectious diseases challenge health and welfare of humans and animals. Unlike for humans, breeding of genetically resistant animals is a sustainable solution, also providing unique research opportunities. Chances to survive a disease are improved by disease resistance, but depend also on chances to get infected and infect others. Considerable knowledge exists on chances of susceptible and resistant animals to survive a disease, yet, almost none on their infectivity and if and how resistance and infectivity correlate. Common carp (Cyprinus carpio) is widely produced in aquaculture, suffering significantly from a disease caused by cyprinid herpes virus type 3 (CyHV-3). Here, the infectivity of disease-resistant and susceptible fish types was tested by playing roles of shedders (infecting) and cohabitants (infected) in all four type-role combinations. Resistant shedders restricted spleen viral load and survived more than susceptible ones. However, mortality of susceptible cohabitants infected by resistant shedders was lower than that of resistant cohabitants infected by susceptible shedders. Virus levels in water were lower in tanks with resistant shedders leading to lower spleen viral loads in cohabitants. Thus, we empirically demonstrated that disease resistant fish survive better and infect less, with implications to epidemiology in general and to the benefit of aquaculture production