Precocious egg development in the blowfly Calliphora vicina : implications for developmental studies and post-mortem interval estimation

The occurrence of precocious egg development in forensically important calliphorid species has previously been reported; however, the frequency of occurrence in both wild and captive colonies, and the consequent effects on developmental studies and post-m

Observer-based control for time-varying delay neural networks with nonlinear observation

This paper studies the problem of designing observer-based controllers for a class of delayed neural networks with nonlinear observation. The system under consideration is subject to nonlinear observation and an interval time-varying delay. The nonlinear observation output is any nonlinear Lipschitzian function and the time-varying delay is not required to be differentiable nor its lower bound be zero. By constructing a set of appropriate Lyapunov-Krasovskii functionals and utilizing the Newton-Leibniz formula, some delay-dependent stabilizability conditions which are expressed in terms of Linear Matrix Inequalities (LMIs) are derived. The derived conditions allow simultaneous computation of two bounds that characterize the exponential stability rate of the closed-loop system. The unknown observer gain and the state feedback observer-based controller are directly obtained upon the feasibility of the derived LMIs stabilizability conditions. A simulation example is presented to verify the effectiveness of the proposed result.

Metacognitive, cognitive and developmental predictors of generalised anxiety disorder symptoms

Generalised anxiety disorder (GAD) is the most significant and common of the anxiety disorders. Intolerance of uncertainty (IU) and negative metacognitive beliefs are two prominent cognitive factors in models of GAD, however only one study to date has examined the relative contribution of these factors. Therefore, this study aimed to investigate and compare these cognitive factors in their prediction of GAD symptoms, and also to examine possible developmental influences on GAD by examining the link between symptoms and the parentification style of childrearing. In this analogue study, 119 non-clinical participants (M age 22.90 years; 95 females, 24 males) completed measures of these constructs. Results indicated that both IU and negative beliefs about worry significantly related to GAD symptoms, however, the degree to which they predicted GAD symptoms did not significantly differ. Although a weak but significant relationship was found between parentification and GAD, this relationship did not remain significant after controlling for depression. Implications and limitations are discussed.

Iniatives to reduce the use of seclusion and restraints on people with developmental disabilities: a systematic review and quantitative synthesis

Contrary to the expectations articulated in public policy, restrictive interventions are commonly used in support services for people with developmental disabilities. This systematic review and quantitative synthesis was undertaken to investigate whether the use of seclusion and restraints on people with developmental disabilities can be reduced. Searches of the Academic Search Complete, CINAHL, MEDLINE, and PsycINFO electronic databases returned 7226 records, of which 11 met the inclusion criteria for this review. A further 3 papers were obtained through scanning the reference lists of those articles included from the initial literature search. All 14 studies were single-subject designs focusing on initiatives to reduce physical or mechanical restraint. Between the baseline and intervention phases, there were mean reductions in the frequency and duration of restraint use of 79% (SD = 21%, n = 13 subjects from 7 studies) and 45% (SD = 58%, n = 10 subjects from 6 studies), respectively. For studies in which restraint use to manage agitation and aggression was targeted, there was a 79% (SD = 21%, n = 13 subjects from 7 studies) decrease in the frequency and a 28% (SD = 67%, n = 6 subjects from 3 studies) reduction in the duration of restraint. With respect to studies in which restraint use to prevent self-harm was targeted, there was a 71% (SD = 34%, n = 4 subjects from 3 studies) reduction in restraint use. Effect sizes were calculable, using non-overlap approaches, for 9 of the 14 studies. The magnitudes of the effect sizes suggest that, on average, the interventions were effective in reducing the use of restraints. The effects generated in studies where restraint use for self-harm was targeted were typically more pronounced than those in which restraint use for agitation and aggression was addressed. There were broad variations, however, in the percentage reductions in restraint use and in the magnitudes of the effect sizes. Although the findings of this review are encouraging, more research is needed, in which greater attention must be paid to rigorous research design, application, and analysis.

Short- and long-term consequences of early developmental conditions : a case study on wild and domesticated zebra finches

Divergent selection pressures among populations can result not only in significant differentiation in morphology, physiology and behaviour, but also in how these traits are related to each other, thereby driving the processes of local adaptation and speciation. In the Australian zebra finch, we investigated whether domesticated stock, bred in captivity over tens of generations, differ in their response to a life-history manipulation, compared to birds taken directly from the wild. In a ‘common aviary’ experiment, we thereto experimentally manipulated the environmental conditions experienced by nestlings early in life by means of a brood size manipulation, and subsequently assessed its short- and long-term consequences on growth, ornamentation, immune function and reproduction. As expected, we found that early environmental conditions had a marked effect on both short- and long-term morphological and life-history traits in all birds. However, although there were pronounced differences between wild and domesticated birds with respect to the absolute expression of many of these traits, which are indicative of the different selection pressures wild and domesticated birds were exposed to in the recent past, manipulated rearing conditions affected morphology and ornamentation of wild and domesticated finches in a very similar way. This suggests that despite significant differentiation between wild and domesticated birds, selection has not altered the relationships among traits. Thus, life-history strategies and investment trade-offs may be relatively stable and not easily altered by selection. This is a reassuring finding in the light of the widespread use of domesticated birds in studies of life-history evolution and sexual selection, and suggests that adaptive explanations may be legitimate when referring to captive bird studies.

Impaired online control in children with developmental coordination disorder reflects development immaturity

The present study aimed to clarify whether a reduced ability to correct movements in-flight observed in children with developmental coordination disorder (DCD) reflects a developmental immaturity or deviance from the typical trajectory. Eighteen children with DCD (8–12 years), 18 age-matched controls, and 12 younger controls (5–7 years) completed a double-step reaching task. Compared to older controls, children with DCD and younger controls showed similarly prolonged reaching when the target unexpectedly shifted at movement onset and were equally slow to correct their reaching trajectory. These results suggest that impaired online control in DCD reflects developmental immaturity, possibly implicating the parietal-cerebellar cortices.

Online motor control in children with developmental coordination disorder: chronometric analysis of double-step reaching performance

Background
Although there are a number of plausible accounts to explain movement clumsiness in children [or developmental coordination disorder (DCD)], the cause(s) of the disorder remain(s) an issue of debate. One aspect of motor control that is particularly important to the fluid expression of skill is rapid online control (ROC). Data on DCD have been conflicting. While some recent work using double-step reaching suggests no difficulty in online control, others suggest deficits (e.g. based on sequential pointing). To help resolve this debate, we suggest two things: use of recent neuro-computational models as a framework for investigating motor control in DCD, and more rigorous investigation of double-step reaching. Our working assumption here is that ROC is only viable through the seamless integration of predictive (or forward) models of movement and feedback-based mechanisms.

Aim
The aim of this chronometric study was to explore ROC in children with DCD using a double-step reaching paradigm. We predicted slower online adjustments in DCD based on the argument that these children manifest a core difficulty in predictive control.

Methods
Participants were a group of 17 children with DCD and 27 typically developing children aged between 7 and 12 years. Visual targets were presented on a 17-inch LCD touch screen, inclined to an angle of 15° from horizontal. The children were instructed to press each target as it appeared as quickly and accurately as possible. For 80% of the trials, the central target location remained unchanged for the duration of the movement (non-jump trials), while for the remaining 20% of trials, the target jumped at movement onset to one of the two peripheral locations (jump trials). Reaction time (RT), movement time (MT) and reaching errors were recorded.

Results
For both groups, RT did not vary according to trial condition, while children with DCD were slower to initiate movement. Further, the MT of children with DCD was prolonged to a far greater extent on jump trials relative to controls, with a large effect size. As well, children with DCD committed significantly more errors, notably a reduced ability to inhibit central responses on jump trials.

Conclusion
Our findings help reconcile some disparate findings in the literature using similar tasks. The pattern of performance in children with DCD suggests impairment in the ability to make rapid online adjustments that are based on a predictive (or internal) model of the action. These results pave the way for future kinematic investigation.