Depression in adolescence.

Adolescence is an important developmental period for understanding the nature, course, and treatment of depression. Recent research concerned with depressive mood, syndromes, and disorders during adolescence is reviewed, including investigations of the prevalence, course, risk factors, and prevention and treatment programs for each of these 3 levels of depressive phenomena in adolescence. A broad biopsychosocial perspective on adolescent depression is recommended, and possible directions for future integrative research are proposed. Based on current research and knowledge, implications for research, program, and national policy are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A normal offsetting technique for automatic mesh generation in three dimensions

A technique, based on a normal offsetting procedure, for the fully automatic generation of meshes suitable for finite element analysis in three dimensions is presented. The method is completely automatic, requiring no user intervention in the process and no special modelling procedures. The method is applied to three-dimensional solid geometries. The procedure positions nodes in the interior domain of an object by offsetting an initial set of nodes on the object boundary along vectors normal to the boundary to define a layer of new interior point locations. The offset points are processed to ensure good nodal spacing appropriate for generating well-shaped elements. Following processing, the offset points become a new boundary surrounding the remaining unmeshed region in the interior of the geometric domain. The offsetting procedure is applied again to this new boundary layer to form another offset layer farther into the domain interior. The offset-process-offset cycle is repeated until the entire region is filled with nodes. Tetrahedral elements are then formed by triangulation of the nodes. The boundary-based technique ensures good quality element shapes for analysis in critical boundary regions and facilitates applications involving integration of mesh generation with design geometry databases. Calculation of nodal locations are based on local parameters avoiding the higher-order time complexities associated with global calculations.     

On the computation of reference signal constraints for guaranteed tracking performance

This paper concerns the problem of determining constraints on reference signals for tracking systems such that the tracking performance can be guaranteed within a specified tolerance for any reference signal satisfying the constraints. We first consider the problem of computing derivative constraints, which are linear constraints on the (vector-valued) reference signal and its time derivatives, and present an off-line algorithm for computing inner approximations to supremal derivative constraint sets based on the hyperplane method for generating inner and outer approximations to the reachable set of states for the controlled system. No simulation is required. We then consider planning problems in which a finite number of parameters are selected to generate the reference signal. The derivative constraints are mapped into this parameter space. The simplicial approximation method is proposed as a method for computing an approximation to the set of admissible parameters. The resulting (linear) parameter constraints characterize a class of reference signals which can be successfully executed by the tracking system, thereby permitting supervisory planning and control to be carried out in the reference signal parameter space without simulating detailed models of the underlying system dynamics. We illustrate the computational algorithm and the application of derivative and parameter constraints for the problem of generating trajectories for a two-axis computer numerical control (CNC) cutting tool.     

Predicting achievement of a low-fat diet: a nutrition intervention for adults with low literacy skills

We investigated serine/threonine protein phosphatase (PP) activity and the expression of PP2A during growth and differentiation of epidermal keratinocytes in culture. Keratinocyte PP activity was strongly inhibited by calyculin A and okadaic acid, indicating that the activity was mainly due to PP2A and PP1. The phosphatase activity decreased to about 20% of the initial (day 1) level by the time of confluence and to about 10% at day 7 postconfluence. In contrast to activity, the level of expression of the PP2A catalytic subunit protein and the mRNA for the two isoforms increased slightly over the period of growth. Keratinocyte differentiation was shown by a significant increase in profilaggrin expression after confluence. Keratinocytes were also cultured from individuals affected with harlequin ichthyosis. This severe hyperkeratotic skin disorder has abnormal lipid structures and is blocked in the PP2A-dependent conversion of phosphorylated profilggrin to the non-phosphorylated filaggrin. The PP activity in harlequin cultures was lower than in normal cultures (about 20% of the subconfluent normal control value) and decreased even further in confluent cultures. In contrast, the level of expression of the PP2A catalytic subunit protein and mRNA for the two isoforms was similar to that of normal keratinocytes and increased with confluence. These results suggest that PP activity in keratinocytes is regulated in a post-translational manner; they also support the possibility of impaired or reduced function of PPs in harlequin ichthyosis.     

Electromyographic activity in a distant muscle during simple voluntary movements: an unexpected hand-eye linkage

PURPOSE: Supraspinal sensorimotor maps contain adjacent representations of the hand and face. These experiments were designed to determine whether interactions between the representations could be detected at the periphery. METHODS: Simultaneous EMG recordings were made from orbicularis oculi and wrist flexor during three conditions, with 50 repetitions each: during exposure to an auditory cue; responding to the auditory cue by wrist flexion; and performing a self-paced wrist flexion in the absence of an auditory cue. RESULTS: In 8 of 10 healthy volunteers, the rectified, averaged EMGs showed small but consistent increases in orbicularis oculi activity during wrist flexion in the two tasks involving that movement, but not in the auditory task alone. CONCLUSION: In one or more of the central sensorimotor maps, voluntary activation of the wrist flexor representation is accompanied by liminal activation of a nearby facial representation which projects to the motoneurons of orbicularis oculi.     

Framing the construct of life satisfaction in terms of older adults' personal goals.

Older adults' life satisfaction can be better understood in light of their personal goals. This study of 179 elders examined (1) how goals correlate with satisfaction, (2) whether elders maintain satisfaction by accommodating goals to past losses, and (3) how correlations between satisfaction and key predictors differ among groups with different goals. Satisfaction was related positively to social maintenance and energetic lifestyle goals and negatively to concerns for improvement, disengagement, stability, and reduced activity. Past losses were correlated with current goals but not with satisfaction, consistent with the notion of accommodation. A cluster analysis identified 5 patterns of goals: high demand, age prescribed, self-focused, socially engaged, and low demand. Correlations between satisfaction and other predictors differed by cluster, suggesting that the determinants of elders' satisfaction depend on personal goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specificity Theory and Optimal Responsiveness: An Outline.

Specificity theory legitimizes the analyst's attempts to tailor the treatment process to improve its efficacy. It recognizes that the analyst's responsiveness effectively draws upon a rich palette of both verbal and nonverbal interventions for therapeutic relating. Dispensing with the notion of analytic neutrality, specificity theory recognizes that each therapist offers something therapeutically unique to a particular patient, which includes but also transcends both theory and technique, encompassing who the therapist is as an individual in innumerable respects. It requires that the therapeutic engagement be continually monitored and adjusted to fit the changing capacities and limitations of the particular therapeutic dyad. The principles of specificity theory are suitable to be used by therapists of different theoretical backgrounds--and further, can be applied as an overarching principle functioning to integrate diverse theoretical approaches. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eliciting reliable uncertainty estimates

Abstract: Knowledge engineers often find that experts' estimates of uncertainty change from one day to the next and therefore often seem unreliable. This article explores the unreliability of probability estimates. Forty undergraduates answered 31 questions concerning the probability of daily events at two separate times. Three answer modalities were available: probability, chances and percent of the time. This paper finds that reliability decreases when answer modalities change from one time to the next. It is hypothesized that problem-solving approaches changed along with the modalities. The subjects represented a wide range in reliability, with the most reliable subjects changing answer modalities less than the unreliable subjects. These results suggest that knowledge engineers should endeavor to have experts express their uncertainty estimates using consistent modalities.     

The thermooxidative stability of cured epoxy resins. I

Prior studies have shown that for many epoxy resin systems significant oxidative degradation occurs in air at temperatures as low as 100°C and that thin oxidized surface layers serve as crack initiators in flexural samples at low strains and can reduce flexural strengths to less than 25% of the original values. This study was undertaken in an attempt to identify predominant degradation pathways and cured resin systems that are thermooxidatively stable in 125°C air. Based on flexural property retention and IR spectral data, the thermooxidative resistance ranking of D.E.R.*332 epoxy resin polymerized with the following is p-toluenesulfonamide > 4,4′-diaminodiphenyl sulfone or sulfanilamide > methylene dianiline ? triethylenetetraamine > 2,5-dimethyl-2,5-diaminohexane. Oxidation of aliphatic amine-cured D.E.R. 332 epoxy resin is initiated by electrophilic attack of oxygen on the lone-pair electrons of the nitrogen to form an amine oxide. Polymer chain cleavage then occurs via Cope reactions. A newly proposed oxidative degradation pathway is described wherein the hydroxylamine products of Cope reactions are further oxidized to nitrones, which then decompose to amides via oxaziridine intermediates. Commercial antioxidants added to an aliphatic amine-cured epoxy resin were ineffective, supporting the conclusion that the predominant degradation mechanism is not free radical in nature. © 1993 John Wiley & Sons, Inc.