Image magnification adapter for cameras Patent

Camera adapter design for image magnification including lens and illuminato

Camera lens adapter magnifies image

Polaroid Land camera with an illuminated 7-power magnifier adapted to the lens, photographs weld flaws. The flaws are located by inspection with a 10-power magnifying glass and then photographed with this device, thus providing immediate pictorial data for use in remedial procedures

Estimating Marginal Returns to Higher Education in the UK

A long-standing issue in the literature on education is whether marginal returns to education fall as education rises. If the population differs in its rate of return, a closely related question is whether marginal returns to higher education fall as a greater fraction of the population enrolls. This paper proposes a nonparametric method of estimating marginal treatment effects in heterogeneous populations, and applies it to this question, examining returns to higher education in the UK. The results indicate that marginal returns to higher education fall as the proportion of the population with higher education rises, consistent with the Becker Woytinsky Lecture hypothesis.

Welfare Work Requirements with Paternalistic Government Preferences

Work requirements in means-tested transfer programs have grown in importance in the U.S. and in some other countries. The theoretical literature which considers their possible optimality generally operates within a traditional welfarist framework where some function of the utility of the poor is maximized. Here we consider a case where society is paternalistic and instead has preferences over the actual work allocations of welfare recipients. With this social welfare function, optimality of work requirements is possible but depends on the accuracy of the screening mechanism which assigns work requirements to some benefit recipients and not others. Numerical simulations show that the accuracy must be high for such optimality to occur. The simulations also show that earnings subsidies can be justified with the type of social welfare function used here.

The Role of Randomized Field Trials in Social Science Research: A Perspective from Evaluations of Reforms of Social Welfare Programs

One of the areas of policy research where randomized field trials have been utilized most intensively is welfare reform. Starting in the late 1960s with experimental tests of a negative income tax and continuing through current experimental tests of recent welfare reforms, randomized evaluations have played a strong and increasing role in informing policy. This paper reviews the record of these experiments and assesses the implications of that record for the use of randomization. The review demonstrates that, while randomized field trials in the area of welfare reform have been professionally conducted and well-run, and have yielded much valuable and credible information, their usefulness has been limited by a number of weaknesses, some of which are inherent in the method and some of which result from constraints imposed by the political process. The conclusion is that randomized field trials have an important but limited role to play in future welfare reform evaluations, and that it is essential that they be supplemented by nonexperimental research.

CHARACTERIZING UNCERTAIN OUTCOMES WITH THE RESTRICTED HT TRANSFORMATION

Restrictions on the hyperbolic trigonometric (HT) transformation are imposed to guarantee that a probability density function is obtained from the maximum likelihood estimation. Performance of the restricted HT transformation using data generated from normal, beta, gamma, logistic, log-normal, Pareto, Weibull, order statistic, and bimodal populations is investigated via sampling experiments. Results suggest that the restricted HT transformaltion is sufficiently flexible to compete with the actual population distributions in most cases. Application of the restricted HT transformation is illustrated by characterizing uncertain net income per acre for community-supported agriculture farms in the northeastern United States.farm management, hyperbolic trigonometric transformation, uncertainty, Farm Management, C2, Q1,