Search PubMed⌕ Search

Biomedical subjects

R A Caldwell

Publications and source records attributed to R A Caldwell.

At least 19 recordsLinked to original sources
PubMed1991

Mediational screening: is the benefit worth the cost?

Argued that Pillow et al. (1991) may have overestimated the benefits of mediational screening and underestimated the costs involved in the procedure. The three benefits they suggest: increased statistical power to detect prevention effects, increased cost-effectiveness, and decreased iatrogenic effects are shown to be modest at best. Costs associated with misclassifying people as either false positives or false negatives are considered in the total cost/benefit analysis of mediational screening. Because we cannot accurately predict who will react to the occurrence of life stress by developing the conditions we are interested in preventing, universal interventions are advocated.

Adaptation, Psychological↗
PubMed1991

Nanosecond kinetic absorption and calorimetric studies of cyclopentenone: the triplet, self-quenching, and the predimerization biradicals.

The photolysis of 2-cyclopentenone has been studied by a combination of kinetic absorption spectrophotometry and time-resolved photoacoustic calorimetry. The lifetime of the cyclopentenone triplet is strongly concentration dependent and corresponds to a value of 380 +/- 75 ns at infinite dilution in acetonitrile. The biradical intermediate (or pair of isomeric biradicals) immediately preceding formation of photodimer forms with very high efficiency upon quenching of triplet cyclopentenone by a second ground state cyclopentenone molecule and has an energy of 47 kcal/mol relative to two molecules of reactant. Quenching of the cyclopentenone triplet by conjugated dienes is much slower than expected, which is the reason that early estimates of the triplet lifetime were much too short.

Calorimetry↗
PubMed1990

Determination of triplet excitation energies of cyclic enones by time-resolved photoacoustic calorimetry.

Energies and lifetimes of triplet states of a series of 2-cyclohexenones have been measured in solution under ambient conditions by time-resolved photoacoustic calorimetry (PAC). The PAC triplet lifetimes are in excellent agreement with lifetimes measured by kinetic absorption spectrophotometry (KAS) using nanosecond flash techniques, indicating that the present data indeed pertain to the enone triplets previously studied using KAS. The data demonstrate that, as previously proposed, the pi pi triplet energies in these systems are indeed correlated with triplet lifetimes, and vary sensibly with the anticipated extent of conformational flexibility of the C = C bond. No evidence supporting formation of metastable trans-cyclohexenones was obtained. The data also demonstrate greater precision and, for lifetimes, greater accuracy than has hitherto been claimed for the PAC technique for study of transients with lifetimes in the 25 ns range.

Calorimetry↗
PubMed1988

The assessment of child abuse potential and the prevention of child abuse and neglect: a policy analysis.

A frequently advocated strategy for increasing the efficiency of child abuse prevention programs is to deliver prevention services to "high-risk" populations. This article critically reviews procedures for the reliable and valid assessment of child abuse potential within an ecological perspective. Factors that limit the usefulness of child abuse risk assessment are discussed. These factors include the uncertain criteria of child abuse and neglect, the low base rate of the phenomenon, and the financial and social costs of such procedures. Finally, the prevention implications of the current and future state of the art in child abuse risk assessment are considered and preventive interventions that do not depend on individual case risk screening are advocated.

Child↗
PubMed1988

Surgical spectrum of aortic stenosis in children: a thirty-year experience with 257 children.

Aortic stenosis accounts for 5 to 6% of infants and children seen for surgical repair of congenital heart disease. The clinical presentation and reported results of operation for aortic stenosis are highly variable. This retrospective review was undertaken to assess our operative mortality and the degree of gradient reduction afforded by each of several surgical techniques used to treat aortic stenosis in children over a 30-year period. Two hundred fifty-seven patients ranging in age from 1 day to 19 years were operated on between 1957 and 1986. The indication for operation included asymptomatic patients with gradients greater than 50 mm Hg to patients in profound cardiogenic shock. The operative mortality for children older than 6 months was 4%, whereas neonates seen with critical aortic stenosis had a 60% mortality. The late mortality was 2%. Eighty percent of surviving patients to date have undergone cardiac catheterization after repair. This shows an overall reduction of 57 mm Hg in the left ventricular-aortic gradient. Patients with supravalvular aortic stenosis and discrete subvalvular aortic stenosis as well as patients undergoing aortic valve replacement showed a reduction in or elimination of associated aortic insufficiency, whereas patients undergoing aortic valvotomy or neonates having valvotomy had a significant increase in demonstrable aortic insufficiency. The incidence of third-degree heart block or cerebral emboli following operation for aortic stenosis was less than 1%. However, the incidence of late bacterial endocarditis following repair was nearly 5%; six of eleven cases occurred in the group with discrete subvalvular aortic stenosis. Twenty-nine (13%) of the 223 long-term survivors have undergone a subsequent procedure for relief of residual or recurrent obstruction; 12 have had insertion of an aortic valve prosthesis, 12 have had insertion of an apicoaortic conduit, and 6 have required repeat aortic valvotomy. These data demonstrate the low operative mortality and excellent hemodynamic benefit of surgical relief of single-level aortic stenosis in children older than neonates. Conduits placed for complex obstructions or operative procedures in neonates have acceptable hemodynamic benefits, but operative mortality remains high.

Adolescent↗
PubMed1982

A preventive program for the newly separated: initial evaluation.

A 6-month long preventive intervention program for newly separated persons was designed on the basis of an analysis of the literature that identified the major stressful elements in the separation experience. Following the implementation of the program, its impact was assessed by contrasting persons who were assigned to the program (n = 100) with newly separated persons who were randomly selected to serve as a no-treatment control group (n = 50). Of the nine dependent measures of adjustment used in this evaluation, five significant posttreatment differences were found, in each case favoring the intervention group. The nature of these significant differences is particularly encouraging in light of the preventively oriented objectives of the intervention program. Detailed analysis of program characteristics resulted in the identification of desirable program modifications that could be implemented when the program is reinstituted.

Adaptation, Psychological↗
PubMed1982

Social support: its structure and impact on marital disruption.

Availability of social support has been hypothesized to play a role in influencing adjustment to marital disruption either directly or by moderating the debilitating effects of stress. Yet previous research has not adequately conceptualized or measured the nature and availability of social support. In an effort to learn more about the structure and impact of social support as it relates to marital disruption, 50 newly separated men and women were interviewed at 2 months and again at 8 months after their separations. The structure of social support was found to include (a) several important sources of support, including family, friends, and the larger community; (b) an index of social activity; and (c) a sense of satisfaction with present marital status. Although the stress associated with separation was positively related to poorer adjustment, certain aspects of social support were found to moderate this relationship.

Adaptation, Psychological↗
PubMed1975

Normative and parametric analyses of school maladjustment.

Format and instructional revisions were made in the TRF, a previously reported school adjustment measure, to extend its diagnostic, prescriptive, and empirical utility. Factor analyses of school adjustment ratings on the revised CARS with a normative sample of "healthy" primary graders demonstrated that while the revisions maintained the scale's original three-factor structure, they increased specific item factor loadings and accounted scale variance. To extend the screening utility of the proposed measure, normative and parametric comparisons are reported describing adjustment ratings for sex, age, and city/country subgroups. Comparisons of children who are or are not referred to a secondary prevention program provide evidence of the CARS discriminative validity and screening potential.

Age Factors↗
PubMedDate not supplied

Child provocativeness and gender as factors contributing to the blaming of victims of physical child abuse.

This study was an investigation of factors contributing to blame attributions directed toward victims of physical child abuse. The total sample consisted of 897 college undergraduates. Subjects read eight vignettes describing physically abusive parent-child interactions, and indicated their attributions of responsibility toward parent and child. We predicted that: (a) aggressively provocative children (compared to nonprovocative) would be ascribed greater blame; (b) male subjects would be more likely to blame the child; (c) in situations in which the abusive parent is male (compared to female), the child would be blamed more; and (d) male children (compared to females) would receive greater blame. The results supported all hypotheses. The data also suggested several interaction effects. Significance tests were supplemented with effect size analyses.

Adolescent↗