Modeling effects on the questioning strategies of the elderly.

Conducted an experiment with 42 70-90 yr old Ss which showed that modeling procedures rapidly increased the use of constraint-seeking questions in a guessing task and reduced the number of questions required to reach a correct answer. The changes took place easily, indicating that an intact and efficient questioning strategy is readily available as part of the problem-solving equipment of the elderly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A framework for testing first-order logic axioms in program verification

Program verification systems based on automated theorem provers rely on user-provided axioms in order to verify domain-specific properties of code. However, formulating axioms correctly (that is, formalizing properties of an intended mathematical interpretation) is non-trivial in practice, and avoiding or even detecting unsoundness can sometimes be difficult to achieve. Moreover, speculating soundness of axioms based on the output of the provers themselves is not easy since they do not typically give counterexamples. We adopt the idea of model-based testing to aid axiom authors in discovering errors in axiomatizations. To test the validity of axioms, users define a computational model of the axiomatized logic by giving interpretations to the function symbols and constants in a simple declarative programming language. We have developed an axiom testing framework that helps automate model definition and test generation using off-the-shelf tools for meta-programming, property-based random testing, and constraint solving. We have experimented with our tool to test the axioms used in Auto-Cert, a program verification system that has been applied to verify aerospace flight code using a first-order axiomatization of navigational concepts, and were able to find counterexamples for a number of axioms.     

Titrating methylphenidate in children with attention-deficit/hyperactivity disorder: is body mass predictive of clinical response?

We report here on strategies aimed at improving the frequency of detectable recombination in plants by increasing the efficiency of selecting double-recombinants in transgenic calli. Gene targeting was approached on the Gln1 and the Pzfloci of Lotus japonicus, using Agrobacterium tumefaciens T-DNA replacement vectors. Large flanking regions, up to 22.9 kb, surrounding a positive selection marker were presented as substrates for homologous recombination. For easier detection of putative recombinants the negative selectable marker cytosine deaminase was inserted at the outside borders of the flanking regions offered for cross-over. A combination of positive and negative selection allowing double-recombinants to grow, while counter-selecting random insertions, was used to select putative targeting events. The more than 1000-fold enrichment observed with replacement vectors designed to minimize gene silencing demonstrated the efficiency of the negative selection. Using five different replacement vectors an estimated total of 18,974 transformation events were taken through the positive-negative selection procedure and 185 resistant calli obtained. Targeting events could not be verified in the survivors by PCR screening and Southern blot analysis. With this approach the frequency of detectable gene targeting in L. japonicus was below 5.3 x 10(-5), despite the large flanking sequences offered for recombination.     

Dependency in day-care and home-care children.

Compared 32 4- and 5-year-old boys and girls who attended full-time group day care with 32 home-care matched Ss on proximity-seeking and attention-seeking measures of dependency. Ss were rated on these measures when they were alone with their mothers, with their mothers and a confederate adult, and with their mothers and a confederate child. No differences between day-care and home-care Ss were obtained. However, there was an interaction between type of care and sex: Although there was no difference between day-care boys and girls, home-care girls sought proximity toward their mothers significantly more often than home-care boys. Since dependency is one of the dimensions on which sex differences are frequently found, results suggest that day-care children may be less sex typed than home-care children. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lymphocyte subclasses and depression.

This study enumerated lymphocyte subclasses in the peripheral circulation of 15 patients with current diagnoses of major depressive disorder using monoclonal antibodies and flow cytometry. Depressed patients were found to have smaller numbers of helper (T4+), suppressor (T8+), and total T cells (T11+) relative to individually matched, normal controls, but no differences occurred between groups in the ratio of helper to suppressor cells. Furthermore, the helper, suppressor, and total T cell counts were found to be inversely related to patients' self-reported depression scores. The peripheral circulation of patients with major depression seems to be characterized by proportionately equal reductions in the numbers of helper and suppressor T cells, with the magnitude of these reductions being related to the severity of clinical depression among such patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in concept utilization among normal and retarded children.

Examined the concepts employed by 100 normal children in kindergarten-Grade 4 (Study 1), and by 48 retarded vs 48 normal children matched for mental ages ranging from 5 to 11 yrs (Study 2). Ss were required to select pairs of pictures from a large array of pictures depicting common objects and to explain the basis for their pairing responses. Factor analysis of the conceptual responses of normal Ss revealed factors for abstraction (nominal and functional concepts as opposed to perceptible concepts) and complimentarity ("go together" responses as opposed to similarity responses). Retarded Ss differed from normals primarily in their use of more complimentary and fewer similarity concepts. The developmental course of concept utilization for normals was characterized as a change from perceptible to nominal and functional concepts, while that for retarded Ss was characterized as a change from complimentary to similarity concepts. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal pulse shape for estimating positions of superimposed pulses

In this correspondence, we determine the optimal pulse shape for estimating positions of superimposed pulses by deriving the Cramer-Rao lower bound (CRLB) on the average estimation error variance and numerically optimizing it with respect to pulse shape. Our results show that a significant improvement in estimation error variance can be achieved relative to Gaussian and rectangular pulse shapes     

Test-case generation from Prolog-based specifications

Automatic test-case generation from Prolog specifications encounters problems due to recursion, evaluable predicates, and term ordering. A metainterpreter that controls recursion by using a deterministic automaton to monitor its progress through the specification is presented. The automaton is also used to define which paths through the specification are to be used as test cases, so the metainterpreter can compare where it is, with where it needs to go. The efficacy of the approach in dealing with evaluable predicates and term ordering problems is also examined     

A developmental study of practical problem solving in adults.

Previous research indicates that young and middle-aged adults perform better than other age groups on problems similar to those they might encounter in their everyday lives. However, elderly adults have not performed better than other age groups on problems designed to give them the advantage. In order to ensure that the problems used in the present study were ones that elderly adults might encounter, elderly adults were recruited to help develop the problems. The resulting problems were administered to adults between the ages of 20 and 80. Performance was found to increase from the 20- to 40-year-old age group and decrease thereafter. Thus, when elderly adults devise practical problems that are intended to give elderly adults the advantage, the elderly adults still perform less well than do middle-aged adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)