Coordination dynamics and attentional costs of continuous and discontinuous bimanual circle drawing movements

It has been suggested that the temporal control of rhythmic unimianual movements is different between tasks requiring continuous (e.g., circle drawing) and discontinuous movements (e.g., finger tapping). Specifically, for continuous movements temporal regularities are ail emergent property, whereas for tasks that involve discontinuities timing is ail explicit part of the action goal. The present experiment further investigated the control of continuous and discontinuous movements by comparing the coordination dynamics and attentional demands of bimanual continuous circle drawing with bimanual intermittent circle drawing. The intermittent task required participants to insert a 400 ms pause between each cycle while circling. Using dual-task methodology, 15 right-handed participants performed the two circle drawing tasks, while vocally responding to randomly presented auditory probes. The circle drawing tasks were performed in symmetrical and asymmetrical coordination modes and at movement frequencies of 1 Hz and 1.7 Hz. Intermittent circle drawing exhibited superior spatial and temporal accuracy and stability than continuous circle drawing supporting the hypothesis that the two tasks have different underlying control processes. In terms of attentional cost, probe RT was significantly slower during the intermittent circle drawing task than the continuous circle drawing task across both coordination modes and movement frequencies. Of interest was the finding that in the intermittent circling task reaction time (RT) to probes presented during the pause between cycles did not differ from the RT to probes occurring during the circling movement. The differences in attentional demands between the intermittent and continuous circle drawing tasks may reflect the operation of explicit event timing and implicit emergent timing processes, respectively. (C) 2008 Elsevier B.V. All rights reserved.

Hybrid Method to Assess Sensitive Process Interruption Costs Due to Faults in Electric Power Distribution Networks

This paper shows a new hybrid method for risk assessment regarding interruptions in sensitive processes due to faults in electric power distribution systems. This method determines indices related to long duration interruptions and short duration voltage variations (SDVV), such as voltage sags and swells in each customer supplied by the distribution network. Frequency of such occurrences and their impact on customer processes are determined for each bus and classified according to their corresponding magnitude and duration. The method is based on information regarding network configuration, system parameters and protective devices. It randomly generates a number of fault scenarios in order to assess risk areas regarding long duration interruptions and voltage sags and swells in an especially inventive way, including frequency of events according to their magnitude and duration. Based on sensitivity curves, the method determines frequency indices regarding disruption in customer processes that represent equipment malfunction and possible process interruptions due to voltage sags and swells. Such approach allows for the assessment of the annual costs associated with each one of the evaluated power quality indices.

Reconfiguration of distribution networks to minimize loss and disruption costs using genetic algorithms

In this paper a computational implementation of an evolutionary algorithm (EA) is shown in order to tackle the problem of reconfiguring radial distribution systems. The developed module considers power quality indices such as long duration interruptions and customer process disruptions due to voltage sags, by using the Monte Carlo simulation method. Power quality costs are modeled into the mathematical problem formulation, which are added to the cost of network losses. As for the EA codification proposed, a decimal representation is used. The EA operators, namely selection, recombination and mutation, which are considered for the reconfiguration algorithm, are herein analyzed. A number of selection procedures are analyzed, namely tournament, elitism and a mixed technique using both elitism and tournament. The recombination operator was developed by considering a chromosome structure representation that maps the network branches and system radiality, and another structure that takes into account the network topology and feasibility of network operation to exchange genetic material. The topologies regarding the initial population are randomly produced so as radial configurations are produced through the Prim and Kruskal algorithms that rapidly build minimum spanning trees. (C) 2009 Elsevier B.V. All rights reserved.

Are there costs in the repeated mating activities of female Southern stink bugs Nezara viridula?

Mating is an energy demanding process, imposing risks to physical injuries, pathogen infection and predation. Nevertheless, repeated and multiple mating are widespread even in insect species where nuptial gifts are not involved. The effects of repeated mating, by the same male, are examined on the reproductive performance of female Southern green stink bug Nezara viridula (L.). Fecundity is reduced in females mated three or four times, although there is increased longevity. Females mated once or twice produce more egg clusters and concentrate egg-laying activity in the early part of adult life, whereas those mating more often lay eggs throughout the life span, with fewer egg clusters. Although fecundity is negatively affected by the number of matings, egg fertility remains unaffected.

A costs structure analysis of the Brazilian sugar and ethanol companies

The Brazil consolidated itself as the largest world producer of sugarcane, sugar and ethanol. The creation of the Programa Nacional do Alcool - PROALCOOL and the growing use of cars with flexible motors were some of the factors that helped to motivate still more the production. Evolutions in the agricultural and industrial research did the Brazilian competitiveness in sugar and ethanol globally elevated, what is evidenced when comparing the amount produced at the country and the production costs, which turned a big one differential. Therefore, the administration of costs is of great relevance to the sugar and ethanol companies, for representing a significant rationalization in the production processes, with economy of resources and the reach of better earnings, besides reducing the operational risk pertinent at the fixed costs of production. Thus, the present work has for objective to analyze the costs structure of sugar and ethanol companies of the Center-south area of the country through an empiric-analytical study based in methodologies and concepts extracted of the costs accounting. It is verified that great part of the costs and operational expenses have variable behavior, a positive factor for the sector reducing the operational risk of the activity. The main restraint of this study is the sample of five years and 10% of the number of plants in Brazil that although they represent 30% of the national production, don`t allow the generalization of the model.

Time- and Fluid-Sensitive Resuscitation for Hemodynamic Support of Children in Septic Shock Barriers to the Implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support Guidelines in a Pediatric Intensive Care Unit in a Developing World

Objectives: To analyze mortality rates of children with severe sepsis and septic shock in relation to time-sensitive fluid resuscitation and treatments received and to define barriers to the implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support guidelines in a pediatric intensive care unit in a developing country. Methods: Retrospective chart review and prospective analysis of septic shock treatment in a pediatric intensive care unit of a tertiary care teaching hospital. Ninety patients with severe sepsis or septic shock admitted between July 2002 and June 2003 were included in this study. Results: Of the 90 patients, 83% had septic shock and 17% had severe sepsis; 80 patients had preexisting severe chronic diseases. Patients with septic shock who received less than a 20-mL/kg dose of resuscitation fluid in the first hour of treatment had a mortality rate of 73%, whereas patients who received more than a 40-mL/kg dose in the first hour of treatment had a mortality rate of 33% (P < 0.05.) Patients treated less than 30 minutes after diagnosis of severe sepsis and septic shock had a significantly lower mortality rate (40%) than patients treated more than 60 Minutes after diagnosis (P < 0.05). Controlling for the risk of mortality, early fluid resuscitation was associated with a 3-fold reduction in the odds of death (odds ratio, 0.33; 95% confidence interval, 0.13-0.85). The most important barriers to achieve adequate severe sepsis and septic shock treatment were lack of adequate vascular access, lack of recognition of early shock, shortage of health care providers, and nonuse of goals and treatment protocols. Conclusions: The mortality rate was higher for children older than years, for those who received less than 40 mL/kg in the first hour, and for those whose treatment was not initiated in the first 30 Minutes after the diagnosis of septic shock. The acknowledgment of existing barriers to a timely fluid administration and the establishment of objectives to overcome these barriers may lead to a more successful implementation of the American College of Critical Care Medicine guidelines and reduced mortality rates for children with septic shock in the developing world.

Associations of serious mental illness with earnings: results from the WHO World Mental Health surveys

Background Burden-of-illness data, which are often used in setting healthcare policy-spending priorities, are unavailable for mental disorders in most countries. Aims To examine one central aspect of illness burden, the association of serious mental illness with earnings, in the World Health Organization (WHO) World Mental Health (WMH) Surveys. Method The WMH Surveys were carried out in 10 high-income and 9 low- and middle-income countries. The associations of personal earnings with serious mental illness were estimated. Results Respondents with serious mental illness earned on average a third less than median earnings, with no significant between-country differences (chi(2)(9)=5.5-8.1, P=0.5-0.79). These losses are equivalent to 0.3-0.8% of total national earnings. Reduced earnings among those with earnings and the increased probability of not earning are both important components of these associations: Conclusions These results add to a growing body of evidence that mental disorders have high societal costs. Decisions about healthcare resource allocation should take these costs into consideration.

The Provisional Paediatric Rheumatology International Trials Organisation/American College of Rheumatology/European League Against Rheumatism disease activity core set for the evaluation of response to therapy in juvenile dermatomyositis: A prospective validation study

Objective. To validate a core set of outcome measures for the evaluation of response to treatment in patients with juvenile dermatomyositis (DM). Methods. In 2001, a preliminary consensus-derived core set for evaluating response to therapy in juvenile DM was established. In the present study, the core set was validated through an evidence-based, large-scale data collection that led to the enrollment of 294 patients from 36 countries. Consecutive patients with active disease were assessed at baseline and after 6 months. The validation procedures included assessment of feasibility, responsiveness, discriminant and construct ability, concordce in the evaluation of response to therapy between physicians and parents, redundancy, internal consistency, and ability to predict a therapeutic response. Results. The following clinical measures were found to be feasible, and to have good construct validity, discriminative ability, and internal consistency; furthermore, they were not redundant, proved responsive to clinically important changes in disease activity, and were associated strongly with treatment outcome and thus were included in the final core set: 1) physician`s global assessment of disease activity, 2) muscle strength, 3) global disease activity measure, 4) parent`s global assessment of patient`s well-being, 5) functional ability, and 6) health-related quality of life. Conclusion. The members of the Paediatric Rheumatology International Trials Organisation, with the endorsement of the American College of Rheumatology and the European Leauge Against Rheumatism, propose a core set of criteria for the evaluation of response of therapy that is scientifically and clinically relevant and statistically validated. The core set will help standardize the conduct and reporting of clinical trials and assist practitioners in deciding whether a child with juvenile DM has responded adequately to therapy.