963 resultados para RETRACTED ARTICLE. SEE


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Timberland is seen as a long-term investment which has recently received increased institutional investor attention in many countries and potentially provides added value in a mixed-asset portfolio. Using the National Council of Real Estate Investment Fiduciaries (NCREIF) timberland series, this paper analyses the risk-adjusted performance and portfolio diversification benefits of timberland in the United States over the period of 1987-2007. U.S. timberland is seen to have been a strongly performed asset class with significant portfolio diversification benefits over this period; with a significant portfolio role separate to that of real estate. However, recent years have seen reduced risk-adjusted returns, with some loss of portfolio diversification benefits of timberland with stocks and real estate. Global drivers are likely to see increased future demand for timberland investment.

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In the study of student learning literature, the traditional view holds that when students are faced with heavy workload, poor teaching, and content that they cannot relate to – important aspects of the learning context, they will more likely utilise the surface approach to learning due to stresses, lack of understanding and lack of perceived relevance of the content (Kreber, 2003; Lizzio, Wilson, & Simons, 2002; Ramdsen, 1989; Ramsden, 1992; Trigwell & Prosser, 1991; Vermunt, 2005). For example, in studies involving health and medical sciences students, courses that utilised student-centred, problem-based approaches to teaching and learning were found to elicit a deeper approach to learning than the teacher-centred, transmissive approach (Patel, Groen, & Norman, 1991; Sadlo & Richardson, 2003). It is generally accepted that the line of causation runs from the learning context (or rather students’ self reported data on the learning context) to students’ learning approaches. That is, it is the learning context as revealed by students’ self-reported data that elicit the associated learning behaviour. However, other research studies also found that the same teaching and learning environment can be perceived differently by different students. In a study of students’ perceptions of assessment requirements, Sambell and McDowell (1998) found that students “are active in the reconstruction of the messages and meanings of assessment” (p. 391), and their interpretations are greatly influenced by their past experiences and motivations. In a qualitative study of Hong Kong tertiary students, Kember (2004) found that students using the surface learning approach reported heavier workload than students using the deep learning approach. According to Kember if students learn by extracting meanings from the content and making connections, they will more likely see the higher order intentions embodied in the content and the high cognitive abilities being assessed. On the other hand, if they rote-learn for the graded task, they fail to see the hierarchical relationship in the content and to connect the information. These rote-learners will tend to see the assessment as requiring memorising and regurgitation of a large amount of unconnected knowledge, which explains why they experience a high workload. Kember (2004) thus postulate that it is the learning approach that influences how students perceive workload. Campbell and her colleagues made a similar observation in their interview study of secondary students’ perceptions of teaching in the same classroom (Campbell et al., 2001). The above discussions suggest that students’ learning approaches can influence their perceptions of assessment demands and other aspects of the learning context such as relevance of content and teaching effectiveness. In other words, perceptions of elements in the teaching and learning context are endogenously determined. This study attempted to investigate the causal relationships at the individual level between learning approaches and perceptions of the learning context in economics education. In this study, students’ learning approaches and their perceptions of the learning context were measured. The elements of the learning context investigated include: teaching effectiveness, workload and content. The authors are aware of existence of other elements of the learning context, such as generic skills, goal clarity and career preparation. These aspects, however, were not within the scope of this present study and were therefore not investigated.

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Machine vision represents a particularly attractive solution for sensing and detecting potential collision-course targets due to the relatively low cost, size, weight, and power requirements of vision sensors (as opposed to radar and TCAS). This paper describes the development and evaluation of a real-time vision-based collision detection system suitable for fixed-wing aerial robotics. Using two fixed-wing UAVs to recreate various collision-course scenarios, we were able to capture highly realistic vision (from an onboard camera perspective) of the moments leading up to a collision. This type of image data is extremely scarce and was invaluable in evaluating the detection performance of two candidate target detection approaches. Based on the collected data, our detection approaches were able to detect targets at distances ranging from 400m to about 900m. These distances (with some assumptions about closing speeds and aircraft trajectories) translate to an advanced warning of between 8-10 seconds ahead of impact, which approaches the 12.5 second response time recommended for human pilots. We overcame the challenge of achieving real-time computational speeds by exploiting the parallel processing architectures of graphics processing units found on commercially-off-the-shelf graphics devices. Our chosen GPU device suitable for integration onto UAV platforms can be expected to handle real-time processing of 1024 by 768 pixel image frames at a rate of approximately 30Hz. Flight trials using manned Cessna aircraft where all processing is performed onboard will be conducted in the near future, followed by further experiments with fully autonomous UAV platforms.

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Solid-phase organic chemistry has rapidly expanded in the last decade, and, as a consequence, so has the need for the development of supports that can withstand the extreme conditions required to facilitate some reactions. The authors here prepare a thermally stable, grafted fluoropolymer support (see Figure for an example) in three solvents, and found that the penetration of the graft was greatest in dichloromethane.

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The genre of narratives has become the genre of choice in many classrooms since the introduction of NAPLAN into Australian schools. Yet, Knapp and Watkins (2005) argue that narratives are the least understood of all the genres. Despite wide-spread acceptance that narratives serve the social purpose of entertaining, they can also be more edgy, offering a powerful social or information role. This paper considers the effects of exposing novices to less standard realms of social discourse and disciplinary knowledge vis-a-vis a more clinical treatment focused on ‘standard’ narratives. I argue that we should not shy away from the challenges of edgy narratives just because our students are novice readers. The same holds true for our work in communities on the edge, that is where poverty, multiculturalism or multilingualism and systemic failure are the norm. I am part of an Australian Research Council (ARC) Linkage Grant (LP 0990289) working in such a community. Like many such situations, teachers in these communities are caught in the fray of establishing a dialogue between the culture of federally mandated performance orientated reforms and the cultures and discourses of the lives and future needs of their students (see Exley & Singh, in press).

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If one clear argument emerged from my doctoral thesis in political science, it is that there is no agreement as to what democracy is. There are over 40 different varieties of democracy ranging from those in the mainstream with subtle or minute differences to those playing by themselves in the corner. And many of these various types of democracy are very well argued, empirically supported, and highly relevant to certain polities. The irony is that the thing which all of these democratic varieties or the ‘basic democracy’ that all other forms of democracy stem from, is elusive. There is no international agreement in the literature or in political practice as to what ‘basic democracy’ is and that is problematic as many of us use the word ‘democracy’ every day and it is a concept of tremendous importance internationally. I am still uncertain as to why this problem has not been resolved before by far greater minds than my own, and it may have something to do with the recent growth in democratic theory this past decade and the innovative areas of thought my thesis required, but I think I’ve got the answer. By listing each type of democracy and filling the column next to this list with the literature associated with these various styles of democracy, I amassed a large and comprehensive body of textual data. My research intended to find out what these various styles of democracy had in common and to create a taxonomy (like the ‘tree of life’ in biology) of democracy to attempt at showing how various styles of democracy have ‘evolved’ over the past 5000 years.ii I then ran a word frequency analysis program or a piece of software that counts the 100 most commonly used words in the texts. This is where my logic came in as I had to make sense of these words. How did they answer what the most fundamental commonalities are between 40 different styles of democracy? I used a grounded theory analysis which required that I argue my way through these words to form a ‘theory’ or plausible explanation as to why these particular words and not others are the important ones for answering the question. It came down to the argument that all 40 styles of democracy analysed have the following in common 1) A concept of a citizenry. 2) A concept of sovereignty. 3) A concept of equality. 4) A concept of law. 5) A concept of communication. 6) And a concept of selecting officials. Thus, democracy is a defined citizenry with its own concept of sovereignty which it exercises through the institutions which support the citizenry’s understandings of equality, law, communication, and the selection of officials. Once any of these 6 concepts are defined in a particular way it creates a style of democracy. From this, we can also see that there can be more than one style of democracy active in a particular government as a citizenry is composed of many different aggregates with their own understandings of the six concepts.

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Bone generation by autogenous cell transplantation in combination with a biodegradable scaffold is one of the most promising techniques being developed in craniofacial surgery. The objective of this combined in vitro and in vivo study was to evaluate the morphology and osteogenic differentiation of bone marrow derived mesenchymal progenitor cells and calvarial osteoblasts in a two-dimensional (2-D) and three-dimensional (3-D) culture environment (Part I of this study) and their potential in combination with a biodegradable scaffold to reconstruct critical-size calvarial defects in an autologous animal model [Part II of this study; see Schantz, J.T., et al. Tissue Eng. 2003;9(Suppl. 1):S-127-S-139; this issue]. New Zealand White rabbits were used to isolate osteoblasts from calvarial bone chips and bone marrow stromal cells from iliac crest bone marrow aspirates. Multilineage differentiation potential was evaluated in a 2-D culture setting. After amplification, the cells were seeded within a fibrin matrix into a 3-D polycaprolactone (PCL) scaffold system. The constructs were cultured for up to 3 weeks in vitro and assayed for cell attachment and proliferation using phase-contrast light, confocal laser, and scanning electron microscopy and the MTS cell metabolic assay. Osteogenic differentiation was analyzed by determining the expression of alkaline phosphatase (ALP) and osteocalcin. The bone marrow-derived progenitor cells demonstrated the potential to be induced to the osteogenic, adipogenic, and chondrogenic pathways. In a 3-D environment, cell-seeded PCL scaffolds evaluated by confocal laser microscopy revealed continuous cell proliferation and homogeneous cell distribution within the PCL scaffolds. On osteogenic induction mesenchymal progenitor cells (12 U/L) produce significantly higher (p < 0.05) ALP activity than do osteoblasts (2 U/L); however, no significant differences were found in osteocalcin expression. In conclusion, this study showed that the combination of a mechanically stable synthetic framework (PCL scaffolds) and a biomimetic hydrogel (fibrin glue) provides a potential matrix for bone tissue-engineering applications. Comparison of osteogenic differentiation between the two mesenchymal cell sources revealed a similar pattern.

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In this conversation, Kevin K. Kumashiro shares his reflections on challenges to publishing anti-oppressive research in educational journals. He then invites eight current and former editors of leading educational research journals--William F. Pinar, Elizabeth Graue, Carl A. Grant, Maenette K. P. Benham, Ronald H. Heck, James Joseph Scheurich, Allan Luke, and Carmen Luke--to critique and expand on his analysis. Kumashiro begins the conversation by describing his own experiences submitting manuscripts to educational research journals and receiving comments by anonymous reviewers and journal editors. He suggests three ways to rethink the collaborative potential of the peer-review process: as constructive, as multilensed, and as situated. The eight current and former editors of leading educational research journals then critique and expand Kumashiro's analysis. Kumashiro concludes the conversation with additional reflections on barriers and contradictions involved in advancing anti-oppressive educational research in educational journals. (Contains 3 notes.)

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In order to estimate the safety impact of roadway interventions engineers need to collect, analyze, and interpret the results of carefully implemented data collection efforts. The intent of these studies is to develop Accident Modification Factors (AMF's), which are used to predict the safety impact of various road safety features at other locations or in upon future enhancements. Models are typically estimated to estimate AMF's for total crashes, but can and should be estimated for crash outcomes as well. This paper first describes data collected with the intent estimate AMF's for rural intersections in the state of Georgia within the United Sates. Modeling results of crash prediction models for the crash outcomes: angle, head-on, rear-end, sideswipe (same direction and opposite direction) and pedestrian-involved crashes are then presented and discussed. The analysis reveals that factors such as the Annual Average Daily Traffic (AADT), the presence of turning lanes, and the number of driveways have a positive association with each type of crash, while the median width and the presence of lighting are negatively associated with crashes. The model covariates are related to crash outcome in different ways, suggesting that crash outcomes are associated with different pre-crash conditions.

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Introduction: Nurse Practitioners (NPs) have an emerging role in the Australian healthcare system. However, there remains a dearth of available data about public understanding of the NP role. ---------- Aim: To evaluate clients’ understanding of the role of the NP and their satisfaction with education received, quality of care and NP knowledge and skill. ---------- Method: All authorised NPs working in a designated NP position in Western Australia and those working in three area health services in New South Wales (NSW) were invited to recruit five consecutive clients to complete the self-administered survey. ---------- Results: Thirty two NPs (NP response rate 93%) recruited 129 clients (client response rate 90%). Two thirds of clients (63%) were aware they were consulting an NP. The majority rated the following NP related outcomes as ‘excellent’ or ‘very good’: education provided (89%); quality of care (95%); and knowledge and skill (93%). Less than half reported an understanding that NPs could prescribe medications (40.5%) or interpret X-rays (33.6%). Clients of NPs practising in a rural or remote setting were more likely than those in an urban setting to have previously consulted an NP (p=0.005), and where applicable would to prefer to see a NP rather than a doctor (p=0.022). ---------- Discussion: Successful implementation and expansion of the NP role requires NP visibility in the community. Despite high levels of satisfaction more awareness of the scope of the NP role is required.

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Emotions play a central role in mediation as they help to define the scope and direction of a conflict. When a party to mediation expresses (and hence entrusts) their emotions to those present in a mediation, a mediator must do more than simply listen - they must attend to these emotions. Mediator empathy is an essential skill for communicating to a party that their feelings have been heard and understood, but it can lead mediators into trouble. Whilst there might exist a theoretical divide between the notions of empathy and sympathy, the very best characteristics of mediators (caring and compassionate nature) may see empathy and sympathy merge - resulting in challenges to mediator neutrality. This article first outlines the semantic difference between empathy and sympathy and the role that intrapsychic conflict can play in the convergence of these behavioural phenomena. It then defines emotional intelligence in the context of a mediation, suggesting that only the most emotionally intelligent mediators are able to emotionally connect with the parties, but maintain an impression of impartiality – the quality of remaining ‘attached yet detached’ to the process. It is argued that these emotionally intelligent mediators have the common qualities of strong self-awareness and emotional self-regulation.

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Background: A bundled approach to central venous catheter care is currently being promoted as an effective way of preventing catheter-related bloodstream infection (CR-BSI). Consumables used in the bundled approach are relatively inexpensive which may lead to the conclusion that the bundle is cost-effective. However, this fails to consider the nontrivial costs of the monitoring and education activities required to implement the bundle, or that alternative strategies are available to prevent CR-BSI. We evaluated the cost-effectiveness of a bundle to prevent CR-BSI in Australian intensive care patients. ---------- Methods and Findings: A Markov decision model was used to evaluate the cost-effectiveness of the bundle relative to remaining with current practice (a non-bundled approach to catheter care and uncoated catheters), or use of antimicrobial catheters. We assumed the bundle reduced relative risk of CR-BSI to 0.34. Given uncertainty about the cost of the bundle, threshold analyses were used to determine the maximum cost at which the bundle remained cost-effective relative to the other approaches to infection control. Sensitivity analyses explored how this threshold alters under different assumptions about the economic value placed on bed-days and health benefits gained by preventing infection. If clinicians are prepared to use antimicrobial catheters, the bundle is cost-effective if national 18-month implementation costs are below $1.1 million. If antimicrobial catheters are not an option the bundle must cost less than $4.3 million. If decision makers are only interested in obtaining cash-savings for the unit, and place no economic value on either the bed-days or the health benefits gained through preventing infection, these cost thresholds are reduced by two-thirds.---------- Conclusions: A catheter care bundle has the potential to be cost-effective in the Australian intensive care setting. Rather than anticipating cash-savings from this intervention, decision makers must be prepared to invest resources in infection control to see efficiency improvements.

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It is noted from observations of Compton (2009), Richards (2008), Taylor and Bennett (2002), and others that succession leadership planning and development fails to receive adequate attention in the corporate sector (see Byham 2002; Richards 2008; Wellins and Byham 2001). This paper acknowledges a marked paucity of systematic succession leadership development in education organisations. The need would seem to be compounded at a time when substantial attrition in the leadership ranks is expected over the next five years, reflecting widespread workforce demographics (Busine and Watt 2005; Jacobzone, Cambois, Chaplain, and Robine 1998; Taylor and Bennett 2002). The Lantern model has been developed in response to a perceived need to offer an integrated, systematic approach to organisational and succession leadership development. The model offers an organising framework for considering succession leadership development in a strategic, integrated way. The concept is based on organisational development and leadership literature which sees leadership development not as a series of 'tacked on' activities but as an organic 'whole of organisation' approach fostering the relevant knowledge, skills and understandings which support and 'grow' leaders as the organisation goes about its business. This paper explores how such an ideal might happen, and it suggests that pursuing such an ideal is timely. The leadership baton is set to shift at an accelerated rate in universities, as for organisations broadly, owing to age-related attrition. Moreover, given the increased complexity and demands of the leadership remit in the education leadership environment, it would seem particularly opportune to explore a framework concentrating on engendering a positive, connected organisational climate capable of growing strategic leadership strength from within. Eight core elements of the model, derived from the literature and practice research, are explored. The Lantern model purports to 'cover the bases' of succession leadership development, with particular reference to the education environment. The model is next described

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Number lines are part of our everyday life (e.g., thermometers, kitchen scales) and are frequently used in primary mathematics as instructional aids, in texts and for assessment purposes on mathematics tests. There are two major types of number lines; structured number lines, which are the focus of this paper, and empty number lines. Structured number lines represent mathematical information by the placement of marks on a horizontal or vertical line which has been marked into proportional segments (Figure 1). Empty number lines are blank lines which students can use for calculations (Figure 2) and are not discussed further here (see van den Heuvel-Panhuizen, 2008, on the role of empty number lines). In this article, we will focus on how students’ knowledge of the structured number line develops and how they become successful users of this mathematical tool.

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This paper was retracted by the Journal of Stem Cells and Development on February 15, 2013.