Birthweight of children with phenylketonuria

The assumption that children with phenylketonuria (PKU) develop normally until birth was brought into question by the recent report that PKU children weigh several hundred grams less at birth than their unaffected siblings. We have examined intrafamily differences in birthweight in 40 sibships with at least one affected and one unaffected child. The difference in mean birthweights computed by taking a weighted average of the intrafamily differences was 69 gm, and the adjusted estimate of the birthweight difference between children with PKU and their siblings, obtained from a fitted multiple regression function, is -51 gm. The findings are not consistent with the large difference in birthweight reported previously and are compatible with the assumption that the intrauterine physical growth of children with classical PKU is not adversely affected.     

The impact of self-efficacy on behavior change and weight change among overweight participants in a weight loss trial.

Despite considerable clinical interest, attempts to link perceived self-efficacy with successful weight control have had mixed success. Definitive data on prospective associations between self-efficacy and weight loss are particularly sparse. This study examined relationships between self-efficacy beliefs, weight control behaviors, and weight change among individuals participating in a weight loss trial (N = 349, 87% women). Cross-sectionally, eating and exercise self-efficacy beliefs were strongly associated with corresponding weight loss behaviors. Self-efficacy beliefs prospectively predicted weight control behavior and weight change during active treatment but not during follow-up. Mediational models indicate that people's weight control behaviors mediate the impact of self-efficacy on weight change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

History-Dependent Impact Ionization Theory Applied to HgCdTe e-APDs

The variation of the gain and the excess noise factor in HgCdTe avalanche photodiodes (APDs) with different junction geometries are compared with published theoretical and numerical work. It is shown that, although some features of the gain curves are reproduced, such as the constant exponential increase in the gain, the theoretical work fails to predict the observed variation of the gain as a function of multiplication layer width. In contrast, a new analytical gain model based on local impact ionization coefficients and a first direct comparison of the prediction of history-dependent impact ionization theory are shown to give a good general fit to the experimental gain data. A generic model of the gain in HgCdTe APDs has been obtained by fitting the analytical local model to gain curves of APDs with various geometries and cut-off wavelengths. The study of different hypotheses on the electric field dependence of the dead-space length and the saturation value of the impact ionization coefficient has shown that a variable dead-space effect has a direct impact on the excess noise of APDs, which is why exact excess noise measurements are necessary to achieve a pertinent estimation of the nonlocal impact ionization function.     

Are You Done Yet?

The single biggest wedge between programmer and manager is arguing over the schedule. Johanna Rothman provides a managerís perspective on how programmers and managers can collaborate effectively.     

Inhibition of migration of neural crest-derived cells by the abnormal mesenchyme of the presumptive aganglionic bowel of ls/ls mice: analysis with aggregation and interspecies chimeras

The terminal bowel is congenitally aganglionic in ls/ls mice. The condition has been associated with an overabundance of laminin and other matrix molecules. Aggregation ls/ls<==>C3H chimeric mice and interspecies mouse<==>quail chimeras were constructed to test the hypothesis that the aganglionosis arises because the ls/ls gut and not the neural crest is abnormal. Demonstration of beta-glucuronidase activity permitted genotypically ls/ls and C3H cells to be distinguished in the ls/ls<==>C3H chimeras. Aganglionosis did not occur in the ls/ls<==>C3H mice and ls/ls neurons were observed in the terminal bowel. Following bactransplantation of control segments of mouse gut into quail host embryos, mouse cells migrated to host targets normally colonized by cells from the neural crest; moreover, quail crest-derived cells entered the mouse gut. In contrast, cells did not migrate to these targets from presumptive aganglionic ls/ls bowel and quail crest-derived cells neither entered the ls/ls gut nor migrated through it. Laminin immunoreactivity was present in the backgrafts of murine colon and was far more abundant and widespread in those from ls/ls than in those from control animals. These data suggest that the presumptive aganglionic ls/ls bowel does not contain crest-derived cells because these cells, which are normal in ls/ls mice, do not enter it. This failure of colonization may be related to the premature formation of neurons outside the abnormal gut, a response that may be promoted by the excessive secretion of laminin by the ls/ls enteric mesenchyme.     

Lessons in solid-state kinetics from nuclear energy research

Studies of solid-state kinetics and related point-defect behavior grew together with the atomic age. As a result of work carried out under the auspices of the atomic energy agencies in various countries, there is now a good understanding of this field, both in its broad outlines and in many of the details. In addition, many problems in the field of reactor materials have been solved, or ways of bypassing them indicated. A further benefit has been the applicability of the knowledge and methodologies developed in this program to new technologies and new materials.