531 resultados para CRITICAL MICELLE CONCENTRATION


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Food is a multidimensional construct. It has social, cultural, economic, psychological, emotional, biological, and political dimensions. It is both a material object and a catalyst for a range of social and cultural action. Richly implicated in the social and cultural milieu, food is a central marker of culture and society. Yet little is known about the messages and knowledges in the school curriculum about food. Popular debates around food in schools are largely connected with biomedical issues of obesity, exercise and nutrition. This is a study of the sociological dimensions of food-related messages, practices and knowledge formations in the primary school curriculum. It uses an exploratory, qualitative case study methodology to identify and examine the food activities of a Year 5 class in a Queensland school. Data was gathered over a twoyear period using observation, documentation and interviews methods. Food was found to be an integral part of the primary school's activity. It had economic, symbolic, pedagogic, and instrumental value. Messages about food were found in the official, enacted and hidden curricular which were framed by a food governance framework of legislation, procedures and norms. In the school studied, food knowledge was commodified as a part of a political economy that centred on an 'eat more' message. Certain foods were privileged over others while myths about energy, fruit, fruit juice and sugar shaped student dispositions, values, norms and action. There was little engagement with the cognitive and behavioural dimensions of food and nutrition. The thesis concludes with recommendations for a whole scale reconsideration of food in schools as curricular content and knowledge.

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While scientists are still debating the level of climate change impact to new weather patterns, there have been some devastating natural disasters worldwide in the last decade. From cyclones to earthquakes and from Tsunamis to landslides, these disasters occur with formidable forces and crushing effects. As one of the most important arrangements to erase the negative influence of natural disasters and help with the recovery and redevelopment of the hit area, reconstruction is of utmost importance in light of sustainable objectives. However, current reconstruction practice confronts quite a lot of criticisms for focusing on providing short-term necessities. How to conduct the post disaster reconstruction in a long-term perspective and achieve sustainable development is thereby a highlight for industry practice and research. This paper introduced an on-going research project which is aimed at establishing an operational framework for improving sustainability performance of post disaster reconstruction by identifying critical sustainable factors and exploring their internal relationships. The research reported in this paper is part of the project. After a comprehensive literature review, 17 potential critical sustainability factors for post disaster reconstruction were identified. Preliminary examination and discussion of the factors was conducted.

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Shaft fracture at an early stage of operation is a common problem for a certain type of wind turbine. To determine the cause of shaft failure a series of experimental tests were conducted to evaluate the chemical composition and mechanical properties. A detail analysis involving macroscopic feature and microstructure analysis of the material of the shaft was also performed to have an in depth knowledge of the cause of fracture. The experimental tests and analysis results show that there are no significant differences in the material property of the main shaft when comparing it with the Standard, EN10083-3:2006. The results show that stress concentration on the shaft surface close to the critical section of the shaft due to rubbing of the annular ring and coupled with high stress concentration caused by the change of inner diameter of the main shaft are the main reasons that result in fracture of the main shaft. In addition, inhomogeneity of the main shaft micro-structure also accelerates up the fracture process of the main shaft. In addition, the theoretical calculation of equivalent stress at the end of the shaft was performed, which demonstrate that cracks can easily occur under the action of impact loads. The contribution of this paper is to provide a reference in fracture analysis of similar main shaft of wind turbines.

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Background: Critical care units are designed and resourced to save lives, yet the provision of end-of-life care is a significant component of nursing work in these settings. Limited research has investigated the actual practices of critical care nurses in the provision of end-of-life care, or the factors influencing these practices. To improve the care that patients at the end of life and their families receive, and to support nurses in the provision of this care, further research is needed. The purpose of this study was to identify critical care nurses' end-of-life care practices, the factors influencing the provision of end-of-life care and the factors associated with specific end-of-life care practices. Methods: A three-phase exploratory sequential mixed-methods design was utilised. Phase one used a qualitative approach involving interviews with a convenience sample of five intensive care nurses to identify their end-of-life care experiences and practices. In phase two, an online survey instrument was developed, based on a review of the literature and the findings of phase one. The survey instrument was reviewed by six content experts and pilot tested with a convenience sample of 28 critical care nurses (response rate 45%) enrolled in a postgraduate critical care nursing subject. The refined survey instrument was used in phase three of this study to conduct a national survey of critical care nurses. Descriptive analyses, exploratory factor analysis and univariate general linear modelling was undertaken on completed survey responses from 392 critical care nurses (response rate 25%). Results: Six end-of-life care practice areas were identified in this study: information sharing, environmental modification, emotional support, patient and family-centred decision making, symptom management and spiritual support. The items most frequently identified as always undertaken by critical care nurses in the provision of end-of-life care were from the information sharing and environmental modification practice areas. Items least frequently identified as always undertaken included items from the emotional support practice area. Eight factors influencing the provision of end-of-life care were identified: palliative values, patient and family preferences, knowledge, preparedness, organisational culture, resources, care planning, and emotional support for nurses. Strong agreement was noted with items reflecting values consistent with a palliative approach and inclusion of patient and family preferences. Variation was noted in agreement for items regarding opportunities for knowledge acquisition in the workplace and formal education, yet most respondents agreed that they felt adequately prepared. A context of nurse-led practice was identified, with variation in access to resources noted. Collegial support networks were identified as a source of emotional support for critical care nurses. Critical care nurses reporting values consistent with a palliative approach and/or those who scored higher on support for patient and family preferences were more likely to be engaged in end-of-life care practice areas identified in this study. Nurses who reported higher levels of preparedness and access to opportunities for knowledge acquisition were more likely to report engaging in interpersonal practices that supported patient and family centred decision making and emotional support of patients and their families. A negative relationship was identified between the explanatory variables of emotional support for nurses and death anxiety, and the patient and family centred decision making practice area. Contextual factors had a limited influence as explanatory variables of specific end-of-life care practice areas. Gender was identified as a significant explanatory variable in the emotional and spiritual support practice areas, with male gender associated with lower summated scores on these practice scales. Conclusions: Critical care nurses engage in practices to share control with and support inclusion of families experiencing death and dying. The most frequently identified end-of-life care practices were those that are easily implemented, practical strategies aimed at supporting the patient at the end of life and the patient's family. These practices arguably require less emotional engagement by the nurse. Critical care nurses' responses reflected values consistent with a palliative approach and a strong commitment to the inclusion of families in end-of-life care, and these factors were associated with engagement in all end-of-life care practice areas. Perceived preparedness or confidence with the provision of end-of-life care was associated with engagement in interpersonal caring practices. Critical care nurses autonomously engage in the provision of end-of-life care within the constraints of an environment designed for curative care and rely on their colleagues for emotional support. Critical care nurses must be adequately prepared and supported to provide comprehensive care in all areas of end-of-life care practice. The findings of this study raise important implications, and informed recommendations for practice, education and further research.

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A qualitative analysis of the expected dilatation strain field in the vicinity of an array of grain-boundary (GB) dislocations is presented. The analysis provides a basis for the prediction of the critical current densities (jc) across low-angle YBa2Cu3O7- (YBCO) GBs as a function of their energy. The introduction of the GB energy allows the extension of the analysis to high-angle GBs using established models which predict the GB energy as a function of misorientation angle. The results are compared to published data for jc across [001]-tilt YBCO GBs for the full range of misorientations, showing a good fit. Since the GB energy is directly related to the GB structure, the analysis may allow a generalization of the scaling behavior of jc with the GB energy. © 1995 The American Physical Society.

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We determined the effect of muscle glycogen concentration and postexercise nutrition on anabolic signaling and rates of myofibrillar protein synthesis after resistance exercise (REX). Sixteen young, healthy men matched for age, body mass, peak oxygen uptake (VO2peak) and strength (one repetition maximum; 1RM) were randomly assigned to either a nutrient or placebo group. After 48 h diet and exercise control, subjects undertook a glycogen-depletion protocol consisting of one-leg cycling to fatigue (LOW), whereas the other leg rested (NORM). The next morning following an overnight fast, a primed, constant infusion of L-[ring-13C6] phenylalanine was commenced and subjects completed 8 sets of 5 unilateral leg press repetitions at 80% 1RM. Immediately after REX and 2 h later, subjects consumed a 500 ml bolus of a protein/CHO (20 g whey + 40 g maltodextrin) or placebo beverage. Muscle biopsies from the vastus lateralis of both legs were taken at rest and 1 and 4 h after REX. Muscle glycogen concentration was higher in the NORM than LOW at all time points in both nutrient and placebo groups (P < 0.05). Postexercise Akt-p70S6K-rpS6 phosphorylation increased in both groups with no differences between legs (P < 0.05). mTORSer2448 phosphorylation in placebo increased 1 h after exercise in NORM (P < 0.05), whereas mTOR increased ?4-fold in LOW (P < 0.01) and ?11 fold in NORM with nutrient (P < 0.01; different between legs P < 0.05). Post-exercise rates of MPS were not different between NORM and LOW in nutrient (0.070 ± 0.022 vs. 0.068 ± 0.018 %/h) or placebo (0.045 ± 0.021 vs. 0.049 ± 0.017 %/h). We conclude that commencing high-intensity REX with low muscle glycogen availability does not compromise the anabolic signal and subsequent rates of MPS, at least during the early (4 h) postexercise recovery period.

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The purpose of this study was to compare the effectiveness of three different recovery modalities - active (ACT), passive (PAS) and contrast temperature water immersion (CTW) - on the performance of repeated treadmill running, lactate concentration and pH. Fourteen males performed two pairs of treadmill runs to exhaustion at 120% and 90% of peak running speed (PRS) over a 4-hour period. ACT, PAS or CTW was performed for 15-min after the first pair of treadmill runs. ACT consisted of running at 40% PRS, PAS consisted of standing stationary and CTW consisted of alternating between 60-s cold (10°C) and 120-s hot (42°C) water immersion. Run times were converted to time to cover set distance using critical power. Type of recovery modality did not have a significant effect on change in time to cover 400 m (Mean±SD; ACT 2.7±3.6 s, PAS 2.9±4.2 s, CTW 4.2±6.9 s), 1000 m (ACT 2.2±4.0 s, PAS 4.8±8.6 s, CTW 2.1±7.2 s) or 5000 m (ACT 1.4±29.0 s, PAS 16.7±58.5 s, CTW 11.7±33.0 s). Post exercise blood lactate concentration was lower in ACT and CTW compared with PAS. Participants reported an increased perception of recovery in the CTW compared with ACT and PAS. Blood pH was not significantly influenced by recovery modality. Data suggest both ACT and CTW reduce lactate accumulation after high intensity running, but high intensity treadmill running performance is returned to baseline 4-hours after the initial exercise bout regardless of the recovery strategy employed.

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Defence projects are typically undertaken within a multi-project-management environment where a common agenda of project managers is to achieve higher project efficiency. This study adopted a multi-facet qualitative approach to investigate factors contributing to or impeding project efficiency in the Defence sector. Semi-structured interviews were undertaken to identify additional factors to those compiled from the literature survey. This was followed by a three-round Delphi study to examine the perceived critical factors of project efficiency. The results showed that project efficiency in the Defence sector went beyond its traditional internally focused scope to one that is externally focused. As a result, efforts are needed on not only those factors related to individual projects but also those factors related to project inter-dependencies and external customers. The management of these factors will help to enhance the efficiency of a project within the Defence sector.

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Railway Bridges deteriorate over time due to different critical factors including, flood, wind, earthquake, collision, and environment factors, such as corrosion, wear, termite attack, etc. In current practice, the contributions of the critical factors, towards the deterioration of railway bridges, which show their criticalities, are not appropriately taken into account. In this paper, a new method for quantifying the criticality of these factors will be introduced. The available knowledge as well as risk analyses conducted in different Australian standards and developed for bridge-design will be adopted. The analytic hierarchy process (AHP) is utilized for prioritising the factors. The method is used for synthetic rating of railway bridges developed by the authors of this paper. Enhancing the reliability of predicting the vulnerability of railway bridges to the critical factors, will be the significant achievement of this research.

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The formation of readily recoverable and reusable organic semiconducting Cu- and AgTCNQ (TCNQ=7,7,8,8-tetracyanoquinodimethane) microstructures decorated with Pt and Pd metallic nanoparticles is described for the effective reduction of CrVI ions in aqueous solution at room temperature using both formic acid and an environmentally friendly thiosulfate reductant. The M-TCNQ (M=metal) materials were formed by electrocrystallisation onto a glassy carbon surface followed by galvanic replacement in the presence of H2PtCl6 or PdCl2 to form the composite material. It was found that loading of the surface with nanoparticles could easily be controlled by changing the metal salt concentration. Significantly, the M-TCNQ substrates facilitated the formation of well-isolated metal nanoparticles on their surfaces under appropriate galvanic replacement conditions. The semiconductor–metal nanoparticle combination was also found to be critical to the catalyst performance, wherein the best-performing material was CuTCNQ modified by well-isolated Pt nanoparticles with both formic acid and thiosulfate ions as the reductant.

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Crest-fixed steel claddings made of thin, high strength steel often suffer from local pull-through failures at their screw connections during high wind events such as storms and hurricanes. Currently there aren't any adequate design provisions for these cladding systems except for the expensive testing provisions. Since the local pull-through failures in the less ductile steel claddings are initiated by transverse splitting at the fastener hole, analytical studies have not been able to determine the pull-through failure loads. Analytical studies could be used if a reliable splitting criterion is available. Therefore a series of two-span cladding tests was conducted on a range of crest-fixed steel cladding systems under simulated wind uplift loads. The strains in the sheeting around the critical fastener holes were measured until the pull-through failure. This paper presents the details of the experimental investigation and the results including a strain criterion for the local pull-through failure.

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In response to a growing interest in art and science interactions and transdisciplinary research strategies, this research project examines the critical and conceptual affordances of ArtScience practice and outlines a new experiential methodology for practice-lead research using a framework of creative becoming. In doing so, the study contributes to the field of ArtScience and transdisciplinary practice, by providing new strategies for creative development and critical enquiry across art and science.

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Purpose: This randomised trial was designed to investigate the activity and toxicity of continuous infusion etoposide phosphate (EP), targeting a plasma etoposide concentration of either 3 μg/ml for five days (5d) or 1 μg/ml for 15 days (15d), in previously untreated SCLC patients with extensive disease. Patients and methods: EP was used as a single agent. Plasma etoposide concentration was monitored on days 2 and 4 in patients receiving 5d EP and on days 2, 5, 8 and 11 in patients receiving 15d EP, with infusion modification to ensure target concentrations were achieved. Treatment was repeated every 21 days for up to six cycles, with a 25% reduction in target concentration in patients with toxicity. Results: The study has closed early after entry of 29 patients (14 with 5d EP, 15 with 15d EP). Objective responses were seen in seven of 12 (58%, confidence interval (CI): 27%-85%) evaluable patients after 5d EP, and two of 14 (14%, CI: 4%42%) evaluable patients after 15d EP (P = 0.038). Grade 3 or 4 neutropenia or leucopenia during the first cycle of treatment was observed in six of 12 patients after 5d EP and 0/14 patients after 15d EP (P = 0.004), with median nadir WBC count of 2.6 x 109/1 after 5d and 5.0 x 109/1 after 15d EP (P = 0.017). Only one of 49 cycles of 15d EP was associated with grade 3 or worse haematological toxicity, compared to 14 of 61 cycles of 5d EP. Conclusions: Although the number of patients entered into this trial was small, the low activity seen at 1 μg/ml in the 15d arm suggests that this concentration is below the therapeutic window in this setting. Further concentration- controlled studies with prolonged EP infusions are required.

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This paper investigates how Enterprise Architecture (EA) evolves due to emerging trends. It specifically explores how EA integrates the Service-oriented Architecture (SOA). Archer’s Morphogenetic theory is used as an analytical approach to distinguish the architectural conditions under which SOA is introduced, to study the relationships between these conditions and SOA introduction, and to reflect on EA evolution (elaborations) that then take place. The paper focuses on reasons for why EA evolution could take place, or not and what architectural changes could happen due to SOA integration. The research builds on sound theoretical foundations to discuss EA evolution in a field that often lacks a solid theoretical groundwork. Specifically, it proposes that critical realism, using the morphogenetic theory, can provide a useful theoretical foundation to study enterprise architecture (EA) evolution. The initial results of a literature review (a-priori model) were extended using explorative interviews. The findings of this study are threefold. First, there are five different levels of EA-SOA integration outcomes. Second, a mature EA, flexible and well-defined EA framework and comprehensive objectives of EA improve the integration outcomes. Third, the analytical separation using Archer’s theory is helpful in order to understand how these different integration outcomes are generated.

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This paper presents a strategy to predict the lifetime of rails subjected to large rolling contact loads that induce ratchetting strains in the rail head. A critical element concept is used to calculate the number of loading cycles needed for crack initiation to occur in the rail head surface. In this technique the finite element method (FEM) is used to determine the maximum equivalent ratchetting strain per load cycle, which is calculated by combining longitudinal and shear stains in the critical element. This technique builds on a previously developed critical plane concept that has been used to calculate the number of cycles to crack initiation in rolling contact fatigue under ratchetting failure conditions. The critical element concept simplifies the analytical difficulties of critical plane analysis. Finite element analysis (FEA) is used to identify the critical element in the mesh, and then the strain values of the critical element are used to calculate the ratchetting rate analytically. Finally, a ratchetting criterion is used to calculate the number of cycles to crack initiation from the ratchetting rate calculated.