136 resultados para circular restricted three-body problem
Resumo:
Three types of shop scheduling problems, the flow shop, the job shop and the open shop scheduling problems, have been widely studied in the literature. However, very few articles address the group shop scheduling problem introduced in 1997, which is a general formulation that covers the three above mentioned shop scheduling problems and the mixed shop scheduling problem. In this paper, we apply tabu search to the group shop scheduling problem and evaluate the performance of the algorithm on a set of benchmark problems. The computational results show that our tabu search algorithm is typically more efficient and faster than the other methods proposed in the literature. Furthermore, the proposed tabu search method has found some new best solutions of the benchmark instances.
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In this paper, three metaheuristics are proposed for solving a class of job shop, open shop, and mixed shop scheduling problems. We evaluate the performance of the proposed algorithms by means of a set of Lawrence’s benchmark instances for the job shop problem, a set of randomly generated instances for the open shop problem, and a combined job shop and open shop test data for the mixed shop problem. The computational results show that the proposed algorithms perform extremely well on all these three types of shop scheduling problems. The results also reveal that the mixed shop problem is relatively easier to solve than the job shop problem due to the fact that the scheduling procedure becomes more flexible by the inclusion of more open shop jobs in the mixed shop.
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In this paper, we propose three meta-heuristic algorithms for the permutation flowshop (PFS) and the general flowshop (GFS) problems. Two different neighborhood structures are used for these two types of flowshop problem. For the PFS problem, an insertion neighborhood structure is used, while for the GFS problem, a critical-path neighborhood structure is adopted. To evaluate the performance of the proposed algorithms, two sets of problem instances are tested against the algorithms for both types of flowshop problems. The computational results show that the proposed meta-heuristic algorithms with insertion neighborhood for the PFS problem perform slightly better than the corresponding algorithms with critical-path neighborhood for the GFS problem. But in terms of computation time, the GFS algorithms are faster than the corresponding PFS algorithms.
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Nursing personnel are consistently identified as one of the occupational groups most at risk of work-related musculoskeletal disorders. During the moving and handling of bariatric patients, the weight of the patient combined with atypical body mass contributes to a significant risk of injury to the care provider and patient. This is further compounded by the shape, mobility and co-operation of the patient. The aim of this study was determine user experiences and design requirements for mobile hoists with bariatric patients. Structured interviews were conducted with six experienced injury management staff from the Manual Task Services department of three hospitals in Adelaide, South Australia. All staff had experience in patient handling, the use of patient handling equipment and the provision of patient handling training. A series of open-ended questions were structured around five main themes: 1) patient factors; 2) building/vehicle space and design; 3) equipment and furniture; 4) communication; and 5) staff issues. Questions focussed on the use of mobile hoists for lifting and transferring bariatric patients. Interviews were supplemented with a walk-through of the hospital to view the types of mobile hoists used, and the location and storage of equipment. Across the three hospitals there were differing classification systems to define bariatric patients. Ensuring patient dignity, respect and privacy were viewed as important in the management and rehabilitation of bariatric patients. Storage and space constraints were considered factors restricting the use of mobile floor hoists, with ceiling hoists being the preferred method for patient transfers. When using mobile floor hoists, the forces required to push, pull and manoeuvre, as well as sudden unstable movements of the hoist were considered important risks factors giving rise to a risk of injury to the care provider. Record keeping and purchasing policies appeared to inhibit the effective use of patient handling equipment. The moving and handling of bariatric patients presents complex and challenging issues. A co-ordinated and collaborative approach for moving and handling bariatric patients is needed across the range of care providers. Designers must consider both user and patient requirements.
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Background: Adolescent idiopathic scoliosis is a complex three-dimensional deformity, involving a lateral deformity in the coronal plane and axial rotation of the vertebrae in the transverse plane. Gravitational loading plays an important biomechanical role in governing the coronal deformity, however, less is known about how they influence the axial deformity. This study investigates the change in three-dimensional deformity of a series of scoliosis patients due to compressive axial loading. Methods: Magnetic resonance imaging scans were obtained and coronal deformity (measured using the coronal Cobb angle) and axial rotations measured for a group of 18 scoliosis patients (Mean major Cobb angle was 43.4 o). Each patient was scanned in an unloaded and loaded condition while compressive loads equivalent to 50% body mass were applied using a custom developed compressive device. Findings: The mean increase in major Cobb angle due to compressive loading was 7.4 o (SD 3.5 o). The most axially rotated vertebra was observed at the apex of the structural curve and the largest average intravertebral rotations were observed toward the limits of the coronal deformity. A level-wise comparison showed no significant difference between the average loaded and unloaded vertebral axial rotations (intra-observer error = 2.56 o) or intravertebral rotations at each spinal level. Interpretation: This study suggests that the biomechanical effects of axial loading primarily influence the coronal deformity, with no significant change in vertebral axial rotation or intravertebral rotation observed between the unloaded and loaded condition. However, the magnitude of changes in vertebral rotation with compressive loading may have been too small to detect given the resolution of the current technique.
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‘Wearable technology’, or the use of specialist technology in garments, is promoted by the electronics industry as the next frontier of fashion. However the story of wearable technology’s relationship with fashion begins neither with the development of miniaturised computers in the 1970s nor with sophisticated ‘smart textiles’ of the twenty-first century, despite what much of the rhetoric suggests. This study examines wearable technology against a longer history of fashion, highlighted by the influential techno-sartorial experiments of a group of early twentieth century avant-gardes including Italian Futurists Giacomo Balla and F.T. Marinetti, Russian Constructivists Varvara Stepanova and Liubov Popova, and Paris-based Cubist, Sonia Delaunay. Through the interdisciplinary framework of fashion studies, the thesis provides a fuller picture of wearable technology framed by the idea of utopia. Using comparative analysis, and applying the theoretical formulations of Fredric Jameson, Louis Marin and Michael Carter, the thesis traces the appearance of three techno-utopian themes from their origins in the machine age experiments of Balla, Marinetti, Stepanova, Popova and Delaunay to their twenty-first century reappearance in a dozen wearable technology projects. By exploring the central thesis that contemporary wearable technology resurrects the techno-utopian ideas and expressions of the early twentieth century, the study concludes that the abiding utopian impetus to embed technology in the aesthetics (prints, silhouettes, and fabrication) and functionality of fashion is to unify subject, society and environment under a totalising technological order.
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For many years, computer vision has lured researchers with promises of a low-cost, passive, lightweight and information-rich sensor suitable for navigation purposes. The prime difficulty in vision-based navigation is that the navigation solution will continually drift with time unless external information is available, whether it be cues from the appearance of the scene, a map of features (whether built online or known a priori), or from an externally-referenced sensor. It is not merely position that is of interest in the navigation problem. Attitude (i.e. the angular orientation of a body with respect to a reference frame) is integral to a visionbased navigation solution and is often of interest in its own right (e.g. flight control). This thesis examines vision-based attitude estimation in an aerospace environment, and two methods are proposed for constraining drift in the attitude solution; one through a novel integration of optical flow and the detection of the sky horizon, and the other through a loosely-coupled integration of Visual Odometry and GPS position measurements. In the first method, roll angle, pitch angle and the three aircraft body rates are recovered though a novel method of tracking the horizon over time and integrating the horizonderived attitude information with optical flow. An image processing front-end is used to select several candidate lines in a image that may or may not correspond to the true horizon, and the optical flow is calculated for each candidate line. Using an Extended Kalman Filter (EKF), the previously estimated aircraft state is propagated using a motion model and a candidate horizon line is associated using a statistical test based on the optical flow measurements and location of the horizon in the image. Once associated, the selected horizon line, along with the associated optical flow, is used as a measurement to the EKF. To evaluate the accuracy of the algorithm, two flights were conducted, one using a highly dynamic Uninhabited Airborne Vehicle (UAV) in clear flight conditions and the other in a human-piloted Cessna 172 in conditions where the horizon was partially obscured by terrain, haze and smoke. The UAV flight resulted in pitch and roll error standard deviations of 0.42° and 0.71° respectively when compared with a truth attitude source. The Cessna 172 flight resulted in pitch and roll error standard deviations of 1.79° and 1.75° respectively. In the second method for estimating attitude, a novel integrated GPS/Visual Odometry (GPS/VO) navigation filter is proposed, using a structure similar to a classic looselycoupled GPS/INS error-state navigation filter. Under such an arrangement, the error dynamics of the system are derived and a Kalman Filter is developed for estimating the errors in position and attitude. Through similar analysis to the GPS/INS problem, it is shown that the proposed filter is capable of recovering the complete attitude (i.e. pitch, roll and yaw) of the platform when subjected to acceleration not parallel to velocity for both the monocular and stereo variants of the filter. Furthermore, it is shown that under general straight line motion (e.g. constant velocity), only the component of attitude in the direction of motion is unobservable. Numerical simulations are performed to demonstrate the observability properties of the GPS/VO filter in both the monocular and stereo camera configurations. Furthermore, the proposed filter is tested on imagery collected using a Cessna 172 to demonstrate the observability properties on real-world data. The proposed GPS/VO filter does not require additional restrictions or assumptions such as platform-specific dynamics, map-matching, feature-tracking, visual loop-closing, gravity vector or additional sensors such as an IMU or magnetic compass. Since no platformspecific dynamics are required, the proposed filter is not limited to the aerospace domain and has the potential to be deployed in other platforms such as ground robots or mobile phones.
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Background Zambia is a sub-Saharan country with one of the highest prevalence rates of HIV, currently estimated at 14%. Poor nutritional status due to both protein-energy and micronutrient malnutrition has worsened this situation. In an attempt to address this combined problem, the government has instigated a number of strategies, including the provision of antiretroviral (ARV) treatment coupled with the promotion of good nutrition. High-energy protein supplement (HEPS) is particularly promoted; however, the impact of this food supplement on the nutritional status of people living with HIV/AIDS (PLHA) beyond weight gain has not been assessed. Techniques for the assessment of nutritional status utilising objective measures of body composition are not commonly available in Zambia. The aim of this study is therefore to assess the impact of a food supplement on nutritional status using a comprehensive anthropometric protocol including measures of skinfold thickness and circumferences, plus the criterion deuterium dilution technique to assess total body water (TBW) and derive fat-free mass (FFM) and fat mass (FM). Methods/Design This community-based controlled and longitudinal study aims to recruit 200 HIV-infected females commencing ARV treatment at two clinics in Lusaka, Zambia. Data will be collected at four time points: baseline, 4-month, 8-month and 12-month follow-up visits. Outcome measures to be assessed include body height and weight, body mass index (BMI), body composition, CD4, viral load and micronutrient status. Discussion This protocol describes a study that will provide a longitudinal assessment of the impact of a food supplement on the nutritional status of HIV-infected females initiating ARVs using a range of anthropometric and body composition assessment techniques.
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There is an abundance of books available on the topic of motherhood and mothering; the majority of these books focus on the vulnerability of babies and young children and the motherwork such vulnerability demands. In particular they focus on what it is right to do in the interests of the child, and particularly his or her growth and development. Such a focus is consistent in Western culture with modern moral frameworks where understandings of goodness have been assimilated to dimensions of human action rather than dimensions of human being, selfhood, or specific forms of life. As Charles Taylor has observed, much modern moral philosophy has focused =on what it is right to do rather than the nature of the good life‘ (1989, 13). The master narratives of motherhood and the prevailing social discourses of intensive1 and sacrificial2 mothering exemplify this view as such narratives and discourses depict =what mothers are expected to do [and] how mothers are supposed to be‘ (Nelson 2001, 140). From such infant/child-focused accounts a canonical maternal identity can be discerned; arguably, it is a restricted one. The majority of these books fail to address questions related to what it means be a mother in particular situated, existing, living realities. For instance, ask a mother with young children what being a mother means to her and she may speak of the challenges she faces balancing paid employment and her role as a mother, or the impact of the demands being made on her time and energy. However, ask a mother with young adult-children3 what being a mother means to her and she may speak in similar tones, but she may also speak in differing tones. For example, a "mature" mother may speak of the "empty nest", the "crowded house" and/or "its revolving front door". She may speak of issues related to the vulnerability of the long term marriage, elder care, or grandparenting, or even disillusionment and disenchantment. The purpose of this research is to explore the identity challenges and prospects of some mothers with young adult-children aged between 18 and 30 years of age in twenty-first century Australia. In interpreting the identity challenges and prospects this particular cohort of mothers encounter in their ordinary, everyday living, a diverse and particular range of maternal experiences.my own included5.have been traced, along with the social and ethical meanings ascribed in them. With an understanding and appreciation of voice as the medium which connects one's inner and outer worlds, this research illuminates the plurality of voices and the multiple layers of meaning in each of these mother's particular living and existing realities. Specifically, this research addresses the narrowly constructed, canonical maternal identity through a critical exploration and reflection on stories, shared in a research context, of the living realities of a group of self-identified "mature", middle-class, Australian mothers with children aged between 18 and 30 years of age6. By appraising the broader familial, historical, social, cultural, institutional, and, importantly, moral contexts in which these mothers are situated, 'thick descriptions' (Geertz 1973, 27)7 of maternal identities, and the challenges and prospects these mothers are negotiating, are provided. In terms of its ethical orientation, the frameworks which support and frame this research reject, repudiate and contest (Nelson 2001) the reduction of ethical concerns to individual or intellectual problems or dilemmas to be solved through the application of a theory derived from reasoned thinking. In dismissing deductive and =theoretical-juridical‘8 approaches, the individualistic orientation entrenched in contemporary Western moral thinking, expressed in the notion of '"what ought I to do" when faced with a problem, issue or dilemma of practical urgency' (Isaacs & Massey 1994, 1), is simultaneously rejected, repudiated and contested (Nelson 2001). In countering such understandings, this research reorients us to the illumination and articulation of who it is good to be, for each of these mothers, in allegiance with those goods which guide and inspire her orientations towards living a good life—a life which embraces and enhances the flourishing of herself and her significant others. With an understanding and appreciation that 'mind is never free of precommitment[—t]here is no innocent eye, nor is there one that penetrates aboriginal reality' (Bruner 1987, 32), this thesis is written with the voices of other interlocutors9. These interlocutors include the voices of my research participants whom I refer to as "research interlocutors", my textual "friends" — those scholars whose work resonates strongly with my orientations—as well as the myriad other voices that speak to mothers, for mothers and about mothers, such as those found in popular and mainstream press and culture. Sometimes these voices resonate; other times dissonance may be heard. In situating this research within these complementary frameworks, this research invites readers to join with me in considering, appreciating and appraising the narrow construction of maternal identity. I seek for this engagement, like the engagements with my research interlocutors, to be 'a meeting of voices, an authentic dialogue that is inclusive of the voices of all concerned participants' (Isaacs 2001, 6). I hope that the voices in this thesis resonate with yours (although, at times, you may feel some dissonance) and that together we can draw closer to the accounting, re-counting and re-stor(y)ing of maternal identities; like concentric circles of witness, the dialogue, ...will thus be expanded rippling into corners where one might both imagine, and least expect. Possibilities, then, are vast; the future exciting (Smith 2007, 397). This research is also shaped and guided by maternal scholarship, a relatively new field of inquiry known as 'motherhood studies' (O'Reilly 2011, xvii) which has its origins within the broader terrain of feminist scholarship. As a work of maternal scholarship, this thesis draws upon and continues the tradition of examining motherhood as it is experienced 'in a social context, as embedded in a political institution: in feminist terms' (Rich 1995, ix). It values mothers, their experiences, their stories, their lives. As such, this research is oriented towards 'matricentric feminism', a particular form of feminist inquiry, politics and theory which is consistent with and receptive to feminist frameworks of care and equal rights (O‘Reilly 2011, 25). A number of complementary conceptual frameworks have been engaged in this research with the thesis presented in three parts: the pre-figurative, configurative and re-configurative. As my particular living experiences provided the initial motivation for this research, an account of the challenges I experienced as a mother with young adult-children are outlined as a Prelude to this thesis. Attention then turns to Part One – Pre-figuring Maternal Identities in which the contextual, conceptual and methodological foundations underpinning this research are explored and outlined. In Chapter One, the prevailing cultural narratives and social discourses supporting and shaping the construction of the canonical maternal identity are outlined. Next, in setting the scholarly context, the critiques — arising from feminist and maternal scholarship — of motherhood as a patriarchal institution, mothering as experience, and mothering as work, are explored. As this research engaged with participants who are embedded in particular middle-class, heterosexual, familial and cultural structures, an exploration of family life cycle theory and main stream media accounts are also incorporated. The terrain in which "mature" mothering within an Australian context is experienced is also outlined, including the notions of "empty nests" and "crowded houses", grandparenting, elder care and women's midlife transition. Chapter Two gives an account of the conceptual ontological, ethical, identity and narrative frameworks underpinning this research. In setting the context for rich interpretations, the characteristics of being human10 are outlined before attention turns to our embodiment and embeddedness in our shared human condition11. From this point, attention then turns to understanding the moral form of human living12. In appreciating the vulnerability inherent in our shared human condition, the ways in which we may experience trouble in our lives is noted. The framing of identity constitution13 as complex, multi-faceted, relationally negotiated and composed is then outlined, followed by an understanding of why narrative is a valuable interpretive tool for interpreting and understanding human experiences. This chapter concludes with an appreciation of the ethical significance of storytelling. The research methodology is then outlined in Chapter Three. The rationale underpinning the adoption of the narrative interviewing technique of in-depth interviewing is explored. In exploring these methodological frameworks, the recruitment and interview processes involved in gathering and interpreting the recorded transcripts of ten Australian mothers with young adult-children are outlined. The method of analysis known as the Listening Guide14 best complements the multi-layered, pluri-vocal nature of narrative accounting. The final section of Chapter Three outlines The Guide, with one mother's recorded transcript used to illustrate this method's step-by-step process. Having gathered an understanding and appreciation of the pluri-vocal, multi-layered nature of narrative and identity constitution, the tone of this thesis changes in Part Two . Configuring Maternal Identities. This section consists of Chapters Four and Five and seeks to find meaning in, and make sense of, the differences and commonalities across these particular accounts. Chapter Four explores the living realities of four Australian mothers with young adult-children: Poppy, Honey, Lily and Heather. In presenting a thick description of these mothers' situated realities, the frameworks.the familial, social, cultural, historical and institutional backgrounds.which have supported and shaped each mother's experiences are illuminated. Simultaneously revealed through these particular accounts are the plurality of goods focusing and moving each mother to the moral form of life, a life of meaning and purpose. The harms challenging some mothers' moral motivations are also revealed in this chapter. Specifically illustrated in Chapter Four are the unique and qualitative differences of particular maternal identity configurations. Chapter Five reveals the commonalities amongst all of the research interlocutors' accounts. This chapter contests the individualistic orientation of many contemporary accounts of motherhood which are aimed at defining or contesting what a "good" mother ought to do. By turning away from such individualistic orientations, the chapter does not seek to define 'the content of obligation' (Taylor 1989, 3) but rather seeks to illuminate and articulate a richer, deeper understanding and appreciation of maternal be-ing and be-coming - that is, who it is good to be, for each of these mothers - in allegiance with those goods that focus and inspire her moral motivations. Part Three - Re-Configuring Maternal Identities, which is comprised of Chapter Six, draws this thesis to a close. In this final chapter, the preconceptions, conditions and aspirations for this mother-centred account of the living realities of a small, local cohort of mothers are reiterated. The insights gathered from the rich, descriptive accounts are illuminated and articulated, and the chapter closes with some suggestions for future research. In a Postlude, I reflect on how this research has been a transformative learning experience in my own life.an experience in which I have been able to not only deeply understand and appreciate the challenges and disorientation I was experiencing but also to identify and reorient my stance in relation to the good. In a practical sense, by offering thick descriptions of the living realities of this cohort of "mature" mothers, this research challenges the canonical maternal identity and questions its relevance for, and effect on, "mature" mothers' identity constitution. By bringing to light the complex existing realities of these particular mothers, this research critiques the canonical maternal identity by illustrating that each mother's life and her identity constitutions are complex, relationally negotiated and composed and that motherhood is an enduring way of being. Through these illustrations, this research engages with and extends understandings of difference feminism. This research, however, not only rejects, repudiates and contests (Nelson 2001) the narrowly defined canonical maternal identity. By illuminating and articulating the goods which shape and inspire these "mature" mothers' motherwork, this research offers a matricentric account which is consistent with and respectful of the particular, situated realities—the broader familial, social, institutional, but most importantly, moral values and frameworks—in which each mother‘s life is embedded and her motherwork oriented. By understanding and appreciating the complex and multiple webs of relationships in which each mother exists, this matricentric re-stor(y)ing of maternal experiences not only understands and appreciates the unique nature of each mother‘s existing realities, it is oriented to the continuing enhancing of the shared pursuit of the good which underpins particular maternal practices and particular maternal ways of being.
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Aim: Up to 60% of older medical patients are malnourished with further decline during hospital stay. There is limited evidence for effective nutrition intervention. Staff focus groups were conducted to improve understanding of potential contextual and cultural barriers to feeding older adults in hospital. Methods: Three focus groups involved 22 staff working on the acute medical wards of a large tertiary teaching hospital. Staff disciplines were nursing, dietetics, speech pathology, occupational therapy, physiotherapy, pharmacy. A semistructured topic guide was used by the same facilitator to prompt discussions on hospital nutrition care including barriers. Focus groups were tape-recorded, transcribed and analysed thematically. Results: All staff recognised malnutrition to be an important problem in older patients during hospital stay and identified patient-level barriers to nutrition care such as non-compliance to feeding plans and hospital-level barriers including nursing staff shortages. Differences between disciplines revealed a lack of a coordinated approach, including poor knowledge of nutrition care processes, poor interdisciplinary communication, and a lack of a sense of shared responsibility/coordinated approach to nutrition care. All staff talked about competing activities at meal times and felt disempowered to prioritise nutrition in the acute medical setting. Staff agreed education and ‘extra hands’ would address most barriers but did not consider organisational change. Conclusions: Redesigning the model of care to reprioritise meal-time activities and redefine multidisciplinary roles and responsibilities would support coordinated nutrition care. However, effectiveness may also depend on hospitalwide leadership and support to empower staff and increase accountability within a team-led approach.
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This study investigated Chinese College English students. perceptions of pragmatics, their pragmatic competence in selected speech acts, strategies they employed in acquiring pragmatic knowledge, as well as their general approach to learning English as a foreign language. The research was triggered by a national curriculum initiative that prioritizes the need for College English students to enhance their ability to use English effectively in different social interactions (Chinese College English Education and Supervisory Committee, 2007). The traditional "grammar-translation" and "examination-oriented" method is believed to have reduced Chinese College English students to what is dubbed "mute" and "deaf" language learners (Zhang, 2008; Zhao, 2009). Many students lack pragmatic knowledge on how to interpret discourse by relating utterances to their meanings, understanding the intention of language users, and how language is used in specific settings (Bachman & Palmer, 1996, 2010). There is an increasing body of literature on awareness-raising of the importance of pragmatic knowledge and strategies for classroom instruction. However, to date, researchers have tended to focus largely on the teaching of pragmatics, rather than on how students acquire pragmatic competence (Bardovi-Harlig & Dornyei, 1998; Du, 2004; Hou, 2007; Ruan, 2007; Schauer, 2009). It is this gap in the research that this study fills, with a focus on different types of pragmatic knowledge, learner perceptions of such knowledge, and learning strategies that College English students employ in the process of learning English in general, and pragmatics in particular. Three strands of theories of second language acquisition (Ellis, 1985, 1994): pragmatics (Levinson, 1983; Mey, 2001; Yule, 1996), intercultural communications (Kramsch, 1998; Samovar & Porter, 1997; Samovar, Porter & McDaniel, 2009) and English as a lingua franca (ELF) (Canagarajah, 2006; Firth, 1996; Pennycook, 2010) were employed to establish a conceptual framework for data collection and analyses. Key constructs derived from the three related theories helped to form a typology for a detailed examination and theorization of the empirical evidence gathered from different sources. Four research instruments: a questionnaire (N=237), Discourse Completion Tasks (DCTs) (N=55), focus group interviews (N=18), and a textbook tasks analysis were employed to collect data for this systematic inquiry. Data collected by different instruments were analyzed and compared by way of a triangulation to enhance its validity and reliability. Major findings derived from different sources highlighted that, although College English students were grammatically advanced language learners, they displayed limited pragmatic knowledge and a highly restricted repertoire of language learning strategies. The majority of the respondents, however, believed that pragmatic knowledge was as important as linguistic knowledge in the process of developing communicative competence for interaction in different contexts. It was argued that a combination of a less than sufficient English proficiency, limited knowledge of pragmatics, inadequate language materials and tasks, and a small stock of language learning strategies, were a major hindrance to effective learning and communication, resulting in pragmatic failures in many intercultural communication situations. As the first systematic study of how Chinese College English students learned pragmatics, the research provided a solid empirical base for developing a tentative model for the learning of pragmatics in a College English classroom in China and similar educational contexts. The model was strengthened by a unique combination of theories of pragmatics, intercultural communication and ELF. Findings from this research provided insights into how Chinese College English students perceived pragmatics in the English as foreign language (EFL) curriculum, the processes of learning, as well as strategies they utilized in developing linguistic and pragmatic knowledge and competence.
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Outdoor workers are exposed to high levels of ultraviolet radiation (UVR) and may thus be at greater risk to experience UVR-related health effects such as skin cancer, sun burn, and cataracts. A number of intervention trials (n=14) have aimed to improve outdoor workers’ work-related sun protection cognitions and behaviours. Only one study however has reported the use of UV-photography as part of a multi-component intervention. This study was performed in the USA and showed long-term (12 months) improvements in work-related sun protection behaviours. Intervention effects of the other studies have varied greatly, depending on the population studied, intervention applied, and measurement of effect. Previous studies have not assessed whether: - Interventions are similarly effective for workers in stringent and less stringent policy organisations; - Policy effect is translated into workers’ leisure time protection; - Implemented interventions are effective in the long-term; - The facial UV-photograph technique is effective in Australian male outdoor workers without a large additional intervention package, and; - Such interventions will also affect workers’ leisure time sun-related cognitions and behaviours. Therefore, the present Protection of Outdoor Workers from Environmental Radiation [POWER]-study aimed to fill these gaps and had the objectives of: a) assessing outdoor workers’ sun-related cognitions and behaviours at work and during leisure time in stringent and less stringent sun protection policy environments; b) assessing the effect of an appearance-based intervention on workers’ risk perceptions, intentions and behaviours over time; c) assessing whether the intervention was equally effective within the two policy settings; and d) assessing the immediate post-intervention effect. Effectiveness was described in terms of changes in sun-related risk perceptions and intentions (as these factors were shown to be main precursors of behaviour change in many health promotion theories) and behaviour. The study purposefully selected and recruited two organisations with a large outdoor worker contingent in Queensland, Australia within a 40 kilometre radius of Brisbane. The two organisations differed in the stringency of implementation and reinforcement of their organisational sun protection policy. Data were collected from 154 male predominantly Australian born outdoor workers with an average age of 37 years and predominantly medium to fair skin (83%). Sun-related cognitions and behaviours of workers were assessed using self-report questionnaires at baseline and six to twelve months later. Variation in follow-up time was due to a time difference in the recruitment of the two organisations. Participants within each organisation were assigned to an intervention or control group. The intervention group participants received a one-off personalised Skin Cancer Risk Assessment Tool [SCRAT]-letter and a facial UV-photograph with detailed verbal information. This was followed by an immediate post-intervention questionnaire within three months of the start of the study. The control group only received the baseline and follow-up questionnaire. Data were analysed using a variety of techniques including: descriptive analyses, parametric and non-parametric tests, and generalised estimating equations. A 15% proportional difference observed was deemed of clinical significance, with the addition of reported statistical significance (p<0.05) where applicable. Objective 1: Assess and compare the current sun-related risk perceptions, intentions, behaviours, and policy awareness of outdoor workers in stringent and less stringent sun protection policy settings. Workers within the two organisations (stringent n=89 and less stringent n=65) were similar in their knowledge about skin cancer, self efficacy, attitudes, and social norms regarding sun protection at work and during leisure time. Participants were predominantly in favour of sun protection. Results highlighted that compared to workers in a less stringent policy organisation working for an organisation with stringent sun protection policies and practices resulted in more desirable sun protection intentions (less willing to tan p=0.03) ; actual behaviours at work (sufficient use of upper and lower body protection, headgear, and sunglasses (p<0.001 for all comparisons), and greater policy awareness (awareness of repercussions if Personal Protective Equipment (PPE) was not used, p<0.001)). However the effect of the work-related sun protection policy was found not to extend to leisure time sun protection. Objective 2: Compare changes in sun-related risk perceptions, intentions, and behaviours between the intervention and control group. The effect of the intervention was minimal and mainly resulted in a clinically significant reduction in work-related self-perceived risk of developing skin cancer in the intervention compared to the control group (16% and 32% for intervention and control group, respectively estimated their risk higher compared to other outdoor workers: , p=0.11). No other clinical significant effects were observed at 12 months follow-up. Objective 3: Assess whether the intervention was equally effective in the stringent sun protection policy organisation and the less stringent sun protection policy organisation. The appearance-based intervention resulted in a clinically significant improvement in the stringent policy intervention group participants’ intention to protect from the sun at work (workplace*time interaction, p=0.01). In addition to a reduction in their willingness to tan both at work (will tan at baseline: 17% and 61%, p=0.06, at follow-up: 54% and 33%, p=0.07, stringent and less stringent policy intervention group respectively. The workplace*time interaction was significant p<0.001) and during leisure time (will tan at baseline: 42% and 78%, p=0.01, at follow-up: 50% and 63%, p=0.43, stringent and less stringent policy intervention group respectively. The workplace*time interaction was significant p=0.01) over the course of the study compared to the less stringent policy intervention group. However, no changes in actual sun protection behaviours were found. Objective 4: Examine the effect of the intervention on level of alarm and concern regarding the health of the skin as well as sun protection behaviours in both organisations. The immediate post-intervention results showed that the stringent policy organisation participants indicated to be less alarmed (p=0.04) and concerned (p<0.01) about the health of their skin and less likely to show the facial UV-photograph to others (family p=0.03) compared to the less stringent policy participants. A clinically significantly larger proportion of participants from the stringent policy organisation reported they worried more about skin cancer (65%) and skin freckling (43%) compared to those in the less stringent policy organisation (46%,and 23% respectively , after seeing the UV-photograph). In summary the results of this study suggest that the having a stringent work-related sun protection policy was significantly related to for work-time sun protection practices, but did not extend to leisure time sun protection. This could reflect the insufficient level of sun protection found in the general Australian population during leisure time. Alternatively, reactance caused by being restricted in personal decisions through work-time policy could have contributed to lower leisure time sun protection. Finally, other factors could have also contributed to the less than optimal leisure time sun protection behaviours reported, such as unmeasured personal or cultural barriers. All these factors combined may have lead to reduced willingness to take proper preventive action during leisure time exposure. The intervention did not result in any measurable difference between the intervention and control groups in sun protection behaviours in this population, potentially due to the long lag time between the implementation of the intervention and assessment at 12-months follow-up. In addition, high levels of sun protection behaviours were found at baseline (ceiling effect) which left little room for improvement. Further, this study did not assess sunscreen use, which was the predominant behaviour assessed in previous effective appearance-based interventions trials. Additionally, previous trials were mainly conducted in female populations, whilst the POWER-study’s population was all male. The observed immediate post-intervention result could be due to more emphasis being placed on sun protection and risks related to sun exposure in the stringent policy organisation. Therefore participants from the stringent policy organisation could have been more aware of harmful effects of UVR and hence, by knowing that they usually protect adequately, not be as alarmed or concerned as the participants from the less stringent policy organisation. In conclusion, a facial UV-photograph and SCRAT-letter information alone may not achieve large changes in sun-related cognitions and behaviour, especially of assessed 6-12 months after the intervention was implemented and in workers who are already quite well protected. Differences found between workers in the present study appear to be more attributable to organisational policy. However, against a background of organisational policy, this intervention may be a useful addition to sun-related workplace health and safety programs. The study findings have been interpreted while respecting a number of limitations. These have included non-random allocation of participants due to pre-organised allocation of participants to study group in one organisation and difficulty in separating participants from either study group. Due to the transient nature of the outdoor worker population, only 105 of 154 workers available at baseline could be reached for follow-up. (attrition rate=32%). In addition the discrepancy in the time to follow-up assessment between the two organisations was a limitation of the current study. Given the caveats of this research, the following recommendations were made for future research: - Consensus should be reached to define "outdoor worker" in terms of time spent outside at work as well as in the way sun protection behaviours are measured and reported. - Future studies should implement and assess the value of the facial UV-photographs in a wide range of outdoor worker organisations and countries. - More timely and frequent follow-up assessments should be implemented in intervention studies to determine the intervention effect and to identify the best timing of booster sessions to optimise results. - Future research should continue to aim to target outdoor workers’ leisure time cognitions and behaviours and improve these if possible. Overall, policy appears to be an important factor in workers’ compliance with work-time use of sun protection. Given the evidence generated by this research, organisations employing outdoor workers should consider stringent implementation and reinforcement of a sun protection policy. Finally, more research is needed to improve ways to generate desirable behaviour in this population during leisure time.
Resumo:
BACKGROUND: Frequent illness and injury among workers with high body mass index (BMI) can raise the costs of employee healthcare and reduce workforce maintenance and productivity. These issues are particularly important in vocational settings such as the military, which require good physical health, regular attendance and teamwork to operate efficiently. The purpose of this study was to compare the incidence of injury and illness, absenteeism, productivity, healthcare usage and administrative outcomes among Australian Defence Force personnel with varying BMI. METHODS: Personnel were grouped into cohorts according to the following ranges for (BMI): normal (18.5-24.9 kg/m²; n = 197), overweight (25-29.9 kg/m²; n = 154) and obese (≥30 kg/m²) with restricted body fat (≤28 % for females, ≤24 % for males) (n = 148) and with no restriction on body fat (n = 180). Medical records for each individual were audited retrospectively to record the incidence of injury and illness, absenteeism, productivity, healthcare usage (i.e., consultation with medical specialists, hospital stays, medical investigations, prescriptions) and administrative outcomes (e.g., discharge from service) over one year. These data were then grouped and compared between the cohorts. RESULTS: The prevalence of injury and illness, cost of medical specialist consultations and cost of medical scans were all higher (p <0.05) in both obese cohorts compared with the normal cohort. The estimated productivity losses from restricted work days were also higher (p <0.05) in the obese cohort with no restriction on body fat compared with the normal cohort. Within the obese cohort, the prevalence of injury and illness, healthcare usage and productivity were not significantly greater in the obese cohort with no restriction on body fat compared with the cohort with restricted body fat. The number of restricted work days, the rate of re-classification of Medical Employment Classification and the rate of discharge from service were similar between all four cohorts. CONCLUSIONS: High BMI in the military increases healthcare usage, but does not disrupt workforce maintenance. The greater prevalence of injury and illness, greater healthcare usage and lower productivity in obese Australian Defence Force personnel is not related to higher levels of body fat.
Resumo:
Pronounced phenotypic shifts in island populations are typically attributed to natural selection, but reconstructing heterogeneity in long-term selective regimes remains a challenge. We examined a scenario of divergence proposed for species colonizing a new environment, involving directional selection with a rapid shift to a new optimum and subsequent stabilization. We provide some of the first empirical evidence for this model of evolution using morphological data from three timescales in an island bird, Zosterops lateralis chlorocephalus. In less than four millennia since separation from its mainland counterpart, a substantial increase in body size has occurred and was probably achieved in fewer than 500 generations after colonization. Over four recent decades, morphological traits have fluctuated in size but showed no significant directional trends, suggesting maintenance of a relatively stable phenotype. Finally, estimates of contemporary selection gradients indicated generally weak directional selection. These results provide a rare description of heterogeneity in long-term natural regimes, and caution that observations of current selection may be of limited value in inferring mechanisms of past adaptation due to a lack of constancy even over short time-frames.
Resumo:
Island races of passerine birds display repeated evolution towards larger body size compared with their continental ancestors. The Capricorn silvereye (Zosterops lateralis chlorocephalus) has become up to six phenotypic standard deviations bigger in several morphological measures since colonization of an island approximately 4000 years ago. We estimated the genetic variance-covariance (G) matrix using full-sib and 'animal model' analyses, and selection gradients, for six morphological traits under field conditions in three consecutive cohorts of nestlings. Significant levels of genetic variance were found for all traits. Significant directional selection was detected for wing and tail lengths in one year and quadratic selection on culmen depth in another year. Although selection gradients on many traits were negative, the predicted evolutionary response to selection of these traits for all cohorts was uniformly positive. These results indicate that the G matrix and predicted evolutionary responses are consistent with those of a population evolving in the manner observed in the island passerine trend, that is, towards larger body size.