30 resultados para negative feedback loop

em Deakin Research Online - Australia


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This thesis tested several explanations for the underlying mechanisms of perseveration in populations with ASD. Explanations considered the role of executive dysfunction with particular emphasis on negative feedback, social interaction, and variations in autistic symptomology. The thesis found that negative feedback had the most infiuence on perseveration in ASD populations.

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Cytokine and growth factor signaling mediates essential roles in the differentiation, proliferation, survival and function of a number of cell lineages. This is achieved via specific receptors located on the surface of target cells, with ligand binding activating key intracellular signal transduction cascades to mediate the requisite cellular outcome. Effective resolution of receptor signaling is also essential, with excessive signaling having the potential for pathological consequences. The Suppressor of cytokine signaling (SOCS) family of proteins represent one important mechanism to extinguish cytokine and growth factor receptor signaling. There are 8 SOCS proteins in mammals; SOCS1-7 and the alternatively named Cytokine-inducible SH2-containing protein (CISH). SOCS1-3 and CISH are predominantly associated with the regulation of cytokine receptor signaling, while SOCS4-7 are more commonly involved in the control of Receptor tyrosine kinase (RTK) signaling. Individual SOCS proteins are typically induced by specific cytokines and growth factors, thereby generating a negative feedback loop. As a consequence of their regulatory properties, SOCS proteins have important functions in development and homeostasis, with increasing recognition of their role in disease, particularly their tumor suppressor and anti-inflammatory functions. This review provides a synthesis of our current understanding of the SOCS family, with an emphasis on their immune and hematopoietic roles.

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OBJECTIVE: Point of service feedback (POSF) enables patients to give health services feedback about their experiences during or immediately after care. Despite the increasing use of POSF, little is known regarding patients' and staffs' opinions of this practice and whether they consider it acceptable or useful. The study aimed to determine patient and staff opinions regarding POSF. DESIGN: A cross-sectional survey. SETTING: Acute and subacute healthcare facilities. PARTICIPANTS: Two hundred and forty-seven patients and 221 staff. RESULTS: Participants indicated that patients should be invited to evaluate health services when they are in hospital or subacute care and improving services was the most important reason for doing so. Staff indicated that:• collecting patients' feedback during their stay was an important part of providing care and not an interruption to it (n = 187 of 221, 85%).• collecting patients' feedback was best done with a variety of methods; talking directly with patients during their stay was the preferred option (n = 161 of 219, 74%).More patients preferred to:• give feedback during their stay (51%) than after discharge from care (15%).• give feedback by talking with someone (45%) than completing a questionnaire (31%).Some patients (14%) were concerned about reprisal from staff if they gave negative feedback. CONCLUSIONS: POSF can be acceptable and useful for evaluating health services and should be incorporated into a person-centred approach that allows patients to choose from a variety of feedback options both during and after their stay. To be most useful, feedback should be incorporated into a quality improvement system.

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The paper proposes an IS process model comprising inputs, development, outputs and a feedback loop based on performance measurement and its interpretation. The feedback impacts on the inputs and development components. Inputs are comprised of market information. human resources, diversity, value creation and host country environmental factors. Development includes preparation and learning. planning and scrutinising partnerships. anticipating impacts of globalisation and experience effects. Outputs comprise structure, scope of operations, target countries. facility location and positioning. Performance interpretation explains rapid and major changes in IS outputs, such as structure and business unit portfolios, whilst process complexity explains observed output similarities for organisations reacting to similar inputs and suggests an evolutionary approach in their determination.

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This paper describes the Mobile Architecture and Built Environment Laboratory (MABEL) and its application for systematic building performance evaluation for compliance testing, commissioning, strategic and operational facility management and continuous improvement in the built environment.

The first part of the paper introduces the application areas of on-site building performance evaluation and discusses the shortcomings in this regard in current practice. It emphasises the need for on-site investigations to generate information on 'as built performance' for the 'feedback' loop between design, operation and occupancy of new buildings, retrofit or adjustment.

The second part introduces the Energy-Comfort-Behaviour Framework for 'across-the-board' building evaluation and discusses MABEL's role in this scheme. MABEL's objectives, procedures and the performance measurement matrix are explained and discussed.

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International strategy (IS) is the approach by which an organisation's capabilities and resources are directed to generate value utilising the global market's opportunities (and risks). Many of the largest multinationals invest significant resources in their IS, however, the literature does not offer any substantive model for the process. This paper presents a model of the IS process which comprises two parts, the first part is made up of inputs, development and outputs and the second comprises a feedback loop based on organisational performance measurement and its interpretation which impacts on the first part stages of inputs and development. The content of the model is explained and justified using examples of practice. Inputs are comprised of market information, human resources, diversity and value creation and host country environmental factors. Development is comprised of preparation and learning, planning and scrutinising partnerships, anticipating impacts of globalisation, anticipating impacts of technology, location, experience effects, planning competencies, planning for cost effectiveness, scenario planning, planning structures and operations, leadership and ethics. Outputs are comprised of structure, scope of operations, target countries, facility location and positioning. Performance interpretation explains rapid and major changes in IS outputs, such as structure
and business unit portfolios, whilst process complexity explains observed output similarities for organisations reacting to similar inputs and suggests an evolutionary approach in their determination.

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The Video Suggestibility Scale for Children (VSSC) was developed by Scullin and colleagues (Scullin & Ceci, 2000; Scullin & Hembrooke, 1998) as a tool for discriminating between children who have different levels of suggestibility. The scale requires children to view a 5-minute video about a birthday party, and to subsequently participate in an interview consisting of 18 yes/no questions. The VSSC consists of two main subscales; Yield (a measure of children's willingness to respond affirmatively to misleading questions about the video) and Shift (a measure of the children's tendency to change their responses after negative feedback from the interviewer). Preliminary research by Scullin and colleagues suggested that the scale possesses satisfactory internal consistency and that children's scores on the VSSC can predict their performance in another suggestibility paradigm. This thesis presents two studies, which further examine the validity and usefulness of the VSSC in an Australian sample of 3- to-5-year-old children. In Study One, children's performance on the VSSC (N = 77) was compared to their performance using other measures of suggestibility. These measures included children's willingness to assent to a false event as well as the number of false interviewer suggestions and new false details that the children provided in their accounts about an independent true-biased and an independent false (non-experienced) event. An independent samples t-test revealed that those children who assented to the false activity generated higher scores on the Yield measure. This pattern was also observed for the Shift subscale although it was not significant. Hierarchical regression analyses revealed that Yield was a significant predictor of the number of false details reported about the false activity, but not the true-biased activity. There was no significant relationship between the Shift Vlll subscale and any of the dependent variables. Overall this study provided partial support for the construct validity of the VSSC. However, it indicated that children's performance on this scale may not be generalisable across different contexts and interview paradigms, and that the Yield subscale is more generalisable than the Shift subscale. Study Two examined whether various group and individual factors that have previously been shown to relate suggestibility (i.e., age, IQ, memory, socio-economic status, gender, temperament) could predict suggestibility as measured by the VSSC. Two hundred and twenty children were recruited from kindergartens, and were divided into two broad socio-economic categories (based predominantly on income). Hierarchical regression analyses revealed that age, intelligence and memory inversely predicted children's Yield suggestibility. Further, children of low socio-economic backgrounds were more suggestible than children of high socio-economic background, and boys were more suggestible than girls on the Yield measure. Although shyness and other internalised and externalised characteristics were explored, no reliable significant relationships were found with Yield. With regard to the Shift subscale, no reliable relationships were found for any of the independent variables except for SES. Overall, results of Study 2 indicated that the VSSC is a potentially useful measure for discriminating between children's suggestibility on the basis on their individual characteristics, although benefits were observed mainly in relation to the Yield subscale. With reference to the findings of these two studies, the potential contribution of the VSSC for research and applied forensic contexts was discussed.

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The building profession is increasingly becoming more demanding with respect to building environmental performance. Intentions are to provide best practices into our buildings. In part, this is a response due to the Australian government and other independent organisations that have developed policy on rating tools and performance ranking measures, all with the intention of accomplishing environmentally sustainable buildings.

With rating systems endorsing innovative environmental design solutions, it could be asked: Are our buildings really operating as rated? Do we know whether our designs are in compliance with what was calculated or simulated? Is there a feedback loop informing the design process on successes or failures in our designs or mechanical services?

While ratings continue to focus on ‘by design’ or ‘as built’ rewards, few tools acknowledge perhaps the more crucial bottom line: ‘as performing’. With the exception of an AGBR (Australian Green Building Rating) scheme on actual annual energy consumption, there appears to be no ‘as performing’ assessment. Furthermore, practically every building is a prototype (a one-off) and requires commissioning, programming and scheduling of its services. It would certainly appear that as stakeholders (the procurers, owners, facilities managers and users) of the newly built environment, that what we really want to know is actual on-site confirmation of performance. It is the objective of the Mobile Architecture and Built Environment Laboratory (MABEL), to provide such a service.

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A conceptual knowledge management (KM) framework was developed and tested. The social bond combined with the expertise of a Community of Practice (CoP) constitutes a bottom-up aproach to KM, at the same time influencing top-down KM efforts by managers. A successful feedback loop between CoP and Management assists in establishing a collaborative and integrated top-down/bottom-up KM strategy.

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The authors have been involved in over ten years of environmental consulting and research on university buildings. Numerous simulations and measurement studies have occurred over this period of time. The intentions have always been to improve and optimise the environmental performing aspects of a building. This paper is a reporting of the implemented strategies, their pre-building research investigation as well as their operational outcomes. Their successes and failures are discussed here. This research is intended as a feedback loop to future design specification, commissioning and maintenance improvements. In hindsight many of the environmental concepts, when executed as planned, were successful. However, often those requiring extensive control, such as lighting, ventilation and mechanical air-conditioning were a failure. The observations between simulation and actual performance are also noted. The paper includes discussion about some of the obstacles in building procurement which can hinder the result of a good environmental performing building.

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Purpose: Motor skills are considered a prerequisite to physical activity, yet the relationship may be reciprocal and perceived sports competence might mediate associations.
Methods: In 2006/2007, 215 adolescents completed motor skill proficiency (Get Skilled Get Active), perceived sport competence (Physical Self-Perception Profile) and physical activity assessments (Adolescent Physical Activity Recall Questionnaire) as part of the Physical Activity and Skills Study. Using AMOS (Version 7.0), reciprocal relationships were examined between motor skill (object control and locomotor) and moderate to vigorous physical activity (MVPA). Both models were then run in different versions to understand the role of perceived sports competence as a potential mediator.
Results: Mean age was 16.4 yr (SD = 0.6), 51.6% (111/215) were females. A reciprocal relationship between object control and MVPA and a one-way relationship from MVPA to locomotor skill was found. When perceived sports competence was examined as a mediator, the best-fitting model versions explained 16% (R² = 0.16)
MVPA variation, and 30% object control (R² = 0.30), and 12% locomotor skill variation (R² = 0.12) (reverse relationship). Perceived sports competence partially mediates the relationship between object control proficiency and physical activity for both directions and fully mediates the relationship between physical activity and locomotor skill; but only when locomotor skill is the outcome.
Conclusions: If the relationship between object control skill and physical activity is viewed as a ‘‘positive feedback loop,’’ skill development and increasing physical activity should simultaneously be targeted in physical activity interventions. Increasing perceived sport competence should also be an intervention focus.

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Sometimes success can be detrimental to learning while failure can be good. What appears as a disaster can often lay the foundations for future success.

Usually, educators and students focus on building confidence through successful completion of learning tasks, summarised by Vygotsky’s zone of proximal development. A positive feedback loop is established if learners are successful in mastering new ideas and skills. The problem is if teachers, trainers and instructors never challenge students to the fullest extent of their abilities, as this might also ensure overconfidence, slow progress and boredom.

We should not avoid the risk of failure; science is all about the possible risk of failure. Testable hypotheses have the potential to fail an experimental or computational test; ideas that are not testable are considered to be outside the realm of science. The occasional failure shows the limits and scope of an idea’s validity and enables us to advance scientific ideas.

There is a need to find the balance between challenge that extends students, and over-extension. The former results in greater and true confidence and ability, while the latter leads to catastrophic failure and crises of confidence. Education, like life and like all scientific endeavour is about taking responsible risks safely. When we cultivate the roses of success that grow from the ashes of disaster, we must not forget that roses have thorns, or that the occasional setback or failure is just as important for learning as a succession of successes.

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Secondary sexual signals are thought to indicate individual quality. In order to understand the evolutionary pressures that give rise to such traits it is important to understand the physiological mechanisms underlying their production. The black bib of the house sparrow Passer domesticus is known to function as a badge of social status in males. Past studies have found that the size of the bib in older males is determined, at least partly, by the androgen testosterone. The immunocompetence handicap hypothesis suggests that testosterone has a key role in maintaining honest signalling – it is both involved in the development or expression of sexual signals and is immunosuppressive. In this paper we test experimentally two hypo theses relating to bib size development, whether 1) testosterone is only immunosuppressive in conditions where the natural feedback loop from the testes has been removed, and 2) testosterone is, in addition to influencing the bib size of older males, responsible for the size of the bib in juvenile sparrows. In the first experiment we found that exogenous testosterone administered to intact males during the winter (when LH and FSH levels are very low and were not artificially increased by castration) caused significant immunosuppression, albeit in interaction with the stress hormone corticosterone. Second, we found that exogenous testosterone administration in castrated fledgling male house sparrows had no effect on subsequent post-juvenile moult bib size relative to controls. Our results suggest that in some circumstances testosterone can be immunosuppressive, but that its role in bib size determination is age-dependent.

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A large corpus of data obtained by means of empirical study of neuromuscular adaptation is currently of limited use to athletes and their coaches. One of the reasons lies in the unclear direct practical utility of many individual trials. This paper introduces a mathematical model of adaptation to resistance training, which derives its elements from physiological fundamentals on the one side, and empirical findings on the other. The key element of the proposed model is what is here termed the athlete’s capability profile. This is a generalization of length and velocity dependent force production characteristics of individual muscles, to an exercise with arbitrary biomechanics. The capability profile, a two-dimensional function over the capability plane, plays the central role in the proposed model of the training-adaptation feedback loop. Together with a dynamic model of resistance the capability profile is used in the model’s predictive stage when exercise performance is simulated using a numerical approximation of differential equations of motion. Simulation results are used to infer the adaptational stimulus, which manifests itself through a fed back modification of the capability profile. It is shown how empirical evidence of exercise specificity can be formulated mathematically and integrated in this framework. A detailed description of the proposed model is followed by examples of its application—new insights into the effects of accommodating loading for powerlifting are demonstrated. This is followed by a discussion of the limitations of the proposed model and an overview of avenues for future work.