325 resultados para open-circuit potential transients


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Mindfulness is a concept which has been widely used in studies on consciousness, but has recently been applied to the understanding of behaviours in other areas, including clinical psychology, meditation, physical activity, education and business. It has been suggested that mindfulness can also be applied to road safety, though this has not yet been researched. A standard definition of mindfulness is “paying attention in a particular way, on purpose in the present moment and non-judgemental to the unfolding of experience moment by moment” [1]. Scales have been developed to measure mindfulness; however, there are different views in the literature on the nature of the mindfulness construct. This paper reviews the issues raised in the literature and arrives at an operational definition of mindfulness considered relevant to road safety. It is further proposed that mindfulness is best construed as operating together with other psychosocial factors to influence road safety behaviours. The specific case of speeding behaviour is outlined, where the psychosocial variables in the Theory of Planned Behaviour (TPB) have been demonstrated to predict both intention to speed and actual speeding behaviour. A role is proposed for mindfulness in enhancing the explanatory and predictive powers of the TPB concerning speeding. The implications of mindfulness for speeding countermeasures are discussed and a program of future research is outlined.

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Following the position of Beer and Burrows (2007) this paper poses a re-conceptualization of Web 2.0 interaction in order to understand the properties of action possibilities in and of Web 2.0. The paper discusses the positioning of Web 2.0 social interaction in light of current descriptions, which point toward the capacities of technology in the production of social affordances within that domain (Bruns 2007; Jenkins 2006; O’Reilly 2005). While this diminishes the agency and reflexivity for users of Web 2.0 it also inadvertently positions tools as the central driver for the interactive potential available (Everitt and Mills 2009; van Dicjk 2009). In doing so it neglects the possibility that participants may be more involved in the production of Web 2.0 than the technology that underwrites it. It is this aspect of Web 2.0 that is questioned in the study with particular interest on how an analytical option may be made available to broaden the scope of investigations into Web 2.0 to include a study of the capacity for an interactive potential in light of how action possibilities are presented to users through communication with others (Bonderup Dohn 2009).

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Despite a central role in angiosperm reproduction, few gametophyte-specific genes and promoters have been isolated, particularly for the inaccessible female gametophyte (embryo sac). Using the Ds-based enhancer-detector line ET253, we have cloned an egg apparatus-specific enhancer (EASE) from Arabidopsis (Arabidopsis thaliana). The genomic region flanking the Ds insertion site was further analyzed by examining its capability to control gusA and GFP reporter gene expression in the embryo sac in a transgenic context. Through analysis of a 5' and 3' deletion series in transgenic Arabidopsis, the sequence responsible for egg apparatus-specific expression was delineated to 77 bp. Our data showed that this enhancer is unique in the Arabidopsis genome, is conserved among different accessions, and shows an unusual pattern of sequence variation. This EASE works independently of position and orientation in Arabidopsis but is probably not associated with any nearby gene, suggesting either that it acts over a large distance or that a cryptic element was detected. Embryo-specific ablation in Arabidopsis was achieved by transactivation of a diphtheria toxin gene under the control of the EASE. The potential application of the EASE element and similar control elements as part of an open-source biotechnology toolkit for apomixis is discussed.

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Articles > Journals > Health journals > Nutrition & Dietetics: The Journal of the Dieticians Association of Australia articles > March 2003 Article: An assessment of the potential of Family Day Care as a nutrition promotion setting in South Australia. (Original Research). Article from:Nutrition & Dietetics: The Journal of the Dieticians Association of Australia Article date:March 1, 2003 Author:Daniels, Lynne A.; Franco, Bunny; McWhinnie, Julie-Anne CopyrightCOPYRIGHT 2006 Dietitians Association of Australia. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights or concerns about this content should be directed to customer service. (Hide copyright information) Related articles Ads by Google TAFE Child Care Courses Government accredited courses. Study anytime, anywhere. www.seeklearning.com.au Get Work in Child Care Certificate III Children's Services 4 Day Course + Take Home Assessment HBAconsult.com.au Abstract Objective: To assess the potential role of Family Day Care in nutrition promotion for preschool children. Design and setting: A questionnaire to examine nutrition-related issues and practices was mailed to care providers registered in the southern region of Adelaide, South Australia. Care providers also supplied a descriptive, qualitative recall of the food provided by parents or themselves to each child less than five years of age in their care on the day closest to completion of the questionnaire. Subjects: 255 care providers. The response rate was 63% and covered 643 preschool children, mean 4.6 (SD 2.8) children per carer. Results: There was clear agreement that nutrition promotion was a relevant issue for Family Day Care providers. Nutrition and food hygiene knowledge was good but only 54% of respondents felt confident to address food quality issues with parents. Sixty-five percent of respondents reported non-neutral approaches to food refusal and dawdling (reward, punishment, cajoling) that overrode the child's control of the amount eaten. The food recalls indicated that most children (> 75%) were offered fruit at least once. Depending on the hours in care, (0 to 4, 5 to 8, greater than 8 hours), 20%, 32% and 55%, respectively, of children were offered milk and 65%, 82% and 87%, respectively, of children were offered high fat and sugar foods. Conclusions: Questionnaire responses suggest that many care providers are committed to and proactive in a range of nutrition promotion activities. There is scope for strengthening skills in the management of common problems, such as food refusal and dawdling, consistent with the current evidence for approaches to early feeding management that promote the development of healthy food preferences and eating patterns. Legitimising and empowering care providers in their nutrition promotion role requires clear policies, guide lines, adequate pre- and in-service training, suitable parent materials, and monitoring.

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Bearing damage in modern inverter-fed AC drive systems is more common than in motors working with 50 or 60 Hz power supply. Fast switching transients and common mode voltage generated by a PWM inverter cause unwanted shaft voltage and resultant bearing currents. Parasitic capacitive coupling creates a path to discharge current in rotors and bearings. In order to analyze bearing current discharges and their effect on bearing damage under different conditions, calculation of the capacitive coupling between the outer and inner races is needed. During motor operation, the distances between the balls and races may change the capacitance values. Due to changing of the thickness and spatial distribution of the lubricating grease, this capacitance does not have a constant value and is known to change with speed and load. Thus, the resultant electric field between the races and balls varies with motor speed. The lubricating grease in the ball bearing cannot withstand high voltages and a short circuit through the lubricated grease can occur. At low speeds, because of gravity, balls and shaft voltage may shift down and the system (ball positions and shaft) will be asymmetric. In this study, two different asymmetric cases (asymmetric ball position, asymmetric shaft position) are analyzed and the results are compared with the symmetric case. The objective of this paper is to calculate the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

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This study was designed to derive central and peripheral oxygen transmissibility (Dk/t) thresholds for soft contact lenses to avoid hypoxia-induced corneal swelling (increased corneal thickness) during open eye wear. Central and peripheral corneal thicknesses were measured in a masked and randomized fashion for the left eye of each of seven subjects before and after 3 h of afternoon wear of five conventional hydrogel and silicone hydrogel contact lens types offering a range of Dk/t from 2.4 units to 115.3 units. Curve fitting for plots of change in corneal thickness versus central and peripheral Dk/t found threshold values of 19.8 and 32.6 units to avoid corneal swelling during open eye contact lens wear for a typical wearer. Although some conventional hydrogel soft lenses are able to achieve this criterion for either central or peripheral lens areas (depending on lens power), in general, no conventional hydrogel soft lenses meet both the central and peripheral thresholds. Silicone hydrogel contact lenses typically meet both the central and peripheral thresholds and use of these lenses therefore avoids swelling in all regions of the cornea. ' 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 92B: 361–365, 2010

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No-tillage (NT) management has been promoted as a practice capable of offsetting greenhouse gas (GHG) emissions because of its ability to sequester carbon in soils. However, true mitigation is only possible if the overall impact of NT adoption reduces the net global warming potential (GWP) determined by fluxes of the three major biogenic GHGs (i.e. CO2, N2O, and CH4). We compiled all available data of soil-derived GHG emission comparisons between conventional tilled (CT) and NT systems for humid and dry temperate climates. Newly converted NT systems increase GWP relative to CT practices, in both humid and dry climate regimes, and longer-term adoption (>10 years) only significantly reduces GWP in humid climates. Mean cumulative GWP over a 20-year period is also reduced under continuous NT in dry areas, but with a high degree of uncertainty. Emissions of N2O drive much of the trend in net GWP, suggesting improved nitrogen management is essential to realize the full benefit from carbon storage in the soil for purposes of global warming mitigation. Our results indicate a strong time dependency in the GHG mitigation potential of NT agriculture, demonstrating that GHG mitigation by adoption of NT is much more variable and complex than previously considered, and policy plans to reduce global warming through this land management practice need further scrutiny to ensure success.

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Excessive grazing pressure is detrimental to plant productivity and may lead to declines in soil organic matter. Soil organic matter is an important source of plant nutrients and can enhance soil aggregation, limit soil erosion, and can also increase cation exchange and water holding capacities, and is, therefore, a key regulator of grassland ecosystem processes. Changes in grassland management which reverse the process of declining productivity can potentially lead to increased soil C. Thus, rehabilitation of areas degraded by overgrazing can potentially sequester atmospheric C. We compiled data from the literature to evaluate the influence of grazing intensity on soil C. Based on data contained within these studies, we ascertained a positive linear relationship between potential C sequestration and mean annual precipitation which we extrapolated to estimate global C sequestration potential with rehabilitation of overgrazed grassland. The GLASOD and IGBP DISCover data sets were integrated to generate a map of overgrazed grassland area for each of four severity classes on each continent. Our regression model predicted losses of soil C with decreased grazing intensity in drier areas (precipitation less than 333 mm yr(-1)), but substantial sequestration in wetter areas. Most (93%) C sequestration potential occurred in areas with MAP less than 1800 mm. Universal rehabilitation of overgrazed grasslands can sequester approximately 45 Tg C yr(-1), most of which can be achieved simply by cessation of overgrazing and implementation of moderate grazing intensity. Institutional level investments by governments may be required to sequester additional C.

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In open railway access markets, a train service provider (TSP) negotiates with an infrastructure provider (IP) for track access rights. This negotiation has been modeled by a multi-agent system (MAS) in which the IP and TSP are represented by separate software agents. One task of the IP agent is to generate feasible (and preferably optimal) track access rights, subject to the constraints submitted by the TSP agent. This paper formulates an IP-TSP transaction and proposes a branch-and-bound algorithm for the IP agent to identify the optimal track access rights. Empirical simulation results show that the model is able to emulate rational agent behaviors. The simulation results also show good consistency between timetables attained from the proposed methods and those derived by the scheduling principles adopted in practice.

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In an open railway access market, the Infrastructure Provider (IP), upon the receipts of service bids from the Train Service Providers (TSPs), assigns track access rights according to its own business objectives and the merits of the bids; and produces the train service timetable through negotiations. In practice, IP chooses to negotiate with the TSPs one by one in such a sequence that IP optimizes its objectives. The TSP bids are usually very complicated, containing a large number of parameters in different natures. It is a difficult task even for an expert to give a priority sequence for negotiations from the contents of the bids. This study proposes the application of fuzzy ranking method to compare and prioritize the TSP bids in order to produce a negotiation sequence. The results of this study allow investigations on the behaviors of the stakeholders in bid preparation and negotiation, as well as evaluation of service quality in the open railway market.

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In an open railway access market, the provisions of railway infrastructures and train services are separated and independent. Negotiations between the track owner and train service providers are thus required for the allocation of the track capacity and the formulation of the services timetables, in which each party, i.e. a stakeholder, exhibits intelligence from the previous negotiation experience to obtain the favourable terms and conditions for the track access. In order to analyse the realistic interacting behaviour among the stakeholders in the open railway access market schedule negotiations, intelligent learning capability should be included in the behaviour modelling. This paper presents a reinforcement learning approach on modelling the intelligent negotiation behaviour. The effectiveness of incorporating learning capability in the stakeholder negotiation behaviour is then demonstrated through simulation.

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Open access reforms to railway regulations allow multiple train operators to provide rail services on a common infrastructure. As railway operations are now independently managed by different stakeholders, conflicts in operations may arise, and there have been attempts to derive an effective access charge regime so that these conflicts may be resolved. One approach is by direct negotiation between the infrastructure manager and the train service providers. Despite the substantial literature on the topic, few consider the benefits of employing computer simulation as an evaluation tool for railway operational activities such as access pricing. This article proposes a multi-agent system (MAS) framework for the railway open market and demonstrates its feasibility by modelling the negotiation between an infrastructure provider and a train service operator. Empirical results show that the model is capable of resolving operational conflicts according to market demand.