Maturation, Spawning Period, and Fecundity of the White Crappie, Pomoxis annularis Rafinesque, in Beaver Reservoir, Arkansas

Gonosomatic indices and ovum diameter frequency distributions showed that the Beaver Reservoir white crappie spawns from late April through May. During the spawning season females release eggs more than once. Various stages of ovarian ovum development were described. Sexual maturity was found in 2-year-old females of 197 mm and 3-year-old and older fish. Regression analyses of fecundity on total length, weight and age of white crappie indicated that the fish weight was the best predictor of fecundity

Analyzing Demand For Disposal And Recycling Services: A Systems Approach

Pricing municipal solid waste (MSW) services using a flat fee offers no incentive to conserve on disposal. This has prompted the use of unit pricing schemes, which should reduce disposal in accordance with demand theory and encourage alternatives such as recycling. Most studies estimate distinct demand equations for disposal and recycling, and none use a systems approach to simultaneous estimate them. To that end, this research estimates such a model, which also recognizes the endogeneity of policy variables. The results offer important policy insight and shed light on the effectiveness of unit pricing in reducing disposal and simultaneously encouraging recycling.

Longer Term Effects of Head Start

Little is known about the long-term effects of participation in Head Start. This paper draws on unique non-experimental data from the Panel Study of Income Dynamics to provide new evidence on the effects of participation in Head Start on schooling attainment, earnings, and criminal behavior. Among whites, participation in Head Start is associated with a significantly increased probability of completing high school and attending college, and we find some evidence of elevated earnings in one's early twenties. African Americans who participated in Head Start are significantly less likely to have been charged or convicted of a crime. The evidence also suggests that there are positive spillovers from older children who attended Head Start to their younger siblings.

Traceability and AOSD - From Requirements to Aspects

The traceability question is addressed through the development of a framework to go from requirements to aspects using the Design by Contract methodology. It is demonstrated that by starting at the requirements stage, and specifying an early aspect in the same semi-formal language as the system's existing requirements, we have the basis from which to design the aspects at the implementation stage. The language of pre- and post-conditions is shown to match closely that of aspects, in that pre-conditions match the aspect's pointcut, and the post-condition matches the advice part of the aspect. This thus gives us traceability from 'early aspects' to 'late aspects'. This approach will shed some light on the relationship between requirements and their refinements to pre- and post conditions, and the traceability of requirements in the face of reuse over time. The addition of a new crosscutting requirement is investigated in terms of the framework, demonstrating the relationship between early and late aspects and traceability. The framework promises to help with the design of the late aspects. We propose the concept of relevancy: information in a requirement beyond its specification as pre- and post-conditions, as a way of identifying join points

The Extent of Job Search during Layoff

macroeconomics,job search, layoff

Hard Choices: Navigating the Economic Shock of Unemployment

During the Great Recession of 2007 to 2009, millions of Americans faced severe economic hardship, forcing difficult decisions about how to stabilize their families' financial well-being and prevent downward economic mobility. Americans with savings were forced to weigh immediate needs against long-term investments, choosing whether to deplete personal assets in order to stay afloat. Those without wealth to fall back on were in an even more precarious position, leading them to turn to family assistance, debt, and other public and private supports when available.This study examines how families weather economic shocks through a close focus on one particular event -- the experience of unemployment, with specific attention to differences by race and family income. The analysis used a nationally representative sample of working-age families from the Panel Study of Income Dynamics or PSID, following the same households from 1999 to 2009. To provide greater insight into the challenges and choices families faced, the report also drew on a unique longitudinal data set of in-depth interviews with 51 families that endured one month or more of unemployment between 1998 and 2012

Preventing childhood obesity by reducing consumption of carbonated drinks: cluster randomised controlled trial

Objective To determine if a school based educational programme aimed at reducing consumption of carbonated drinks can prevent excessive weight gain in children. Design Cluster randomised controlled trial. Setting Six primary schools in southwest England. Participants 644 children aged 7-11 years. Intervention Focused educational programme on nutrition over one school year. Main outcome measures Drink consumption and number of overweight and obese children. Results Consumption of carbonated drinks over three days decreased by 0.6 glasses (average glass size 250 ml) in the intervention group but increased by 0.2 glasses in the control group (mean difference 0.7, 95% confidence interval 0.1 to 1.3). At 12 months the percentage of overweight and obese children increased in the control group by 7.5%, compared with a decrease in the intervention group of 0.2% (mean difference 7.7%, 2.2% to 13.1%). Conclusion A targeted, school based education programme produced a modest reduction in the number of carbonated drinks consumed, which was associated with a reduction in the number of overweight and obese children

Is what you see what you get? representations, metaphors and tools in mathematics didactics

This paper is exploratory in character. The aim is to investigate ways in which it is possible to use the theoretical concepts of representations, tools and metaphors to try to understand what learners of mathematics ‘see’ during classroom interactions (in their widest sense) and what they might get from such interactions. Through an analysis of a brief classroom episode, the suggestion is made that what learners see may not be the same as what they get. From each of several theoretical perspectives utilised in this paper, what learners ‘get’ appears to be something extra. According to our analysis, this something ‘extra’ is likely to depend on the form of technology being used and the representations and metaphors that are available to both teacher and learner