953 resultados para determinants of plant community diversity and structure


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While it is generally accepted in the learning and teaching literature that assessment is the single biggest influence on how students approach their learning, assessment methods within higher education are generally conservative and inflexible. Constrained by policy and accreditation requirements and the need for the explicit articulation of assessment standards for public accountability purposes, assessment tasks can fail to engage students or reflect the tasks students will face in the world of practice. Innovative assessment design can simultaneously deliver program objectives and active learning through a knowledge transfer process which increases student participation. This social constructivist view highlights that acquiring an understanding of assessment processes, criteria and standards needs active student participation. Within this context, a peer-assessed, weekly, assessment task was introduced in the first “serious” accounting subject offered as part of an undergraduate degree. The positive outcomes of this assessment innovation was that student failure rates declined 15%, tutorial participation increased fourfold, tutorial engagement increased six-fold and there was a 100% approval rating for the retention of the assessment task. In contributing to the core conference theme of “seismic” shifts within higher education, in stark contrast to the positive student response, staff-related issues of assessment conservatism and the necessity of meeting increasing research commitments, threatened the assessment task’s survival. These opposing forces to change have the potential to weaken the ability of higher education assessment arrangements to adequately serve either a new generation of students or the sector's community stakeholders.

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At the international level, the higher education sector is currently being subjected to increased calls for public accountability and the current move by the OECD to rank universities based on the quality of their teaching and learning outcomes. At the national level, Australian universities and their teaching staff face numerous challenges including financial restrictions, increasing student numbers and the reality of an increasingly diverse student population. The Australian higher education response to these competing policy and accreditation demands focuses on precise explicit systems and procedures which are inflexible and conservative and which ignore the fact that assessment is the single biggest influence on how students approach their learning. By seriously neglecting the quality of student learning outcomes, assessment tasks are often failing to engage students or reflect the tasks students will face in the world of practice. Innovative assessment design, which includes new paradigms of student engagement and learning and pedagogically based technologies have the capacity to provide some measure of relief from these internal and external tensions by significantly enhancing the learning experience for an increasingly time-poor population of students. That is, the assessment process has the ability to deliver program objectives and active learning through a knowledge transfer process which increases student participation and engagement. This social constructivist view highlights the importance of peer review in assisting students to participate and collaborate as equal members of a community of scholars with both their peers and academic staff members. As a result of increasing the student’s desire to learn, peer review leads to more confident, independent and reflective learners who also become more skilled at making independent judgements of their own and others' work. Within this context, in Case Study One of this project, a summative, peer-assessed, weekly, assessment task was introduced in the first “serious” accounting subject offered as part of an undergraduate degree. The positive outcomes achieved included: student failure rates declined 15%; tutorial participation increased fourfold; tutorial engagement increased six-fold; and there was a 100% student-based approval rating for the retention of the assessment task. However, in stark contrast to the positive student response, staff issues related to the loss of research time associated with the administration of the peer-review process threatened its survival. This paper contributes to the core conference topics of new trends and experiences in undergraduate assessment education and in terms of innovative, on-line, learning and teaching practices, by elaborating the Case Study Two “solution” generated to this dilemma. At the heart of the resolution is an e-Learning, peer-review process conducted in conjunction with the University of Melbourne which seeks to both create a virtual sense of belonging and to efficiently and effectively meet academic learning objectives with minimum staff involvement. In outlining the significant level of success achieved, student-based qualitative and quantitative data will be highlighted along with staff views in a comparative analysis of the advantages and disadvantages to both students and staff of the staff-led, peer review process versus its on-line counterpart.

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Arts managers play a critical role in creating a strong, sustainable arts and cultural sector. They operate as brokers, creating programs, and, more critically, coordinating the relationships between artists, audiences, communities, governments and sponsors required to make these programs a success. Based on study of model developed for a subject in the Master of Creative Industries (Creative Production & Arts Management) at Queensland University of Technology (QUT), this paper examines the pros and cons of a “community of practice” approach in training arts management students to act as cultural brokers. It provides data on the effectiveness of a range of activities – including Position Papers, Case Studies, Masterclasses, and offline and online conversations – that can be used facilitate the peer-to-peer engagement by which students work together to build their cultural brokering skills in a community of practice. The data demonstrates that, whilst students appreciate this approach, educators must provide enough access to voices of authority – that is, to arts professionals – to establish a well-functioning community of practice, and ensure that more expert students do not become frustrated when they are unwittingly and unwillingly thrust into this role by less expert classmates. This is especially important in arts management, where classes are always diverse, due to the fact that most dedicated programs in Australia, as in the US, UK and Europe, are taught via small-scale programs at graduate level which accept applicants from a wide variety of arts and non-arts backgrounds.

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Background Cancer can be a distressing experience for cancer patients and carers, impacting on psychological, social, physical and spiritual functioning. However, health professionals often fail to detect distress in their patients due to time constraints and a lack of experience. Also, with the focus on the patient, carer needs are often overlooked. This study investigated the acceptability of brief distress screening with the Distress Thermometer (DT) and Problem List (PL) to operators of a community-based telephone helpline, as well as to cancer patients and carers calling the service. Methods Operators (n = 18) monitored usage of the DT and PL with callers (cancer patients/carers, >18 years, and English-speaking) from September-December 2006 (n = 666). The DT is a single item, 11-point scale to rate level of distress. The associated PL identifies the cause of distress. Results The DT and PL were used on 90% of eligible callers, most providing valid responses. Benefits included having an objective, structured and consistent means for distress screening and triage to supportive care services. Reported challenges included apparent inappropriateness of the tools due to the nature of the call or level of caller distress, the DT numeric scale, and the level of operator training. Conclusions We observed positive outcomes to using the DT and PL, although operators reported some challenges. Overcoming these challenges may improve distress screening particularly by less experienced clinicians, and further development of the PL items and DT scale may assist with administration. The DT and PL allow clinicians to direct/prioritise interventions or referrals, although ongoing training and support is critical in distress screening.

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Background: Panicum streak virus (PanSV; Family Geminiviridae; Genus Mastrevirus) is a close relative of Maize streak virus (MSV), the most serious viral threat to maize production in Africa. PanSV and MSV have the same leafhopper vector species, largely overlapping natural host ranges and similar geographical distributions across Africa and its associated Indian Ocean Islands. Unlike MSV, however, PanSV has no known economic relevance. Results: Here we report on 16 new PanSV full genome sequences sampled throughout Africa and use these together with others in public databases to reveal that PanSV and MSV populations in general share very similar patterns of genetic exchange and geographically structured diversity. A potentially important difference between the species, however, is that the movement of MSV strains throughout Africa is apparently less constrained than that of PanSV strains. Interestingly the MSV-A strain which causes maize streak disease is apparently the most mobile of all the PanSV and MSV strains investigated. Conclusion: We therefore hypothesize that the generally increased mobility of MSV relative to other closely related species such as PanSV, may have been an important evolutionary step in the eventual emergence of MSV-A as a serious agricultural pathogen. The GenBank accession numbers for the sequences reported in this paper are GQ415386-GQ415401. © 2009 Varsani et al; licensee BioMed Central Ltd.

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Psittacine beak and feather disease (PBFD) has a broad host range and is widespread in wild and captive psittacine populations in Asia, Africa, the Americas, Europe and Australasia. Beak and feather disease circovirus (BFDV) is the causative agent. BFDV has an ~2 kb single stranded circular DNA genome encoding just two proteins (Rep and CP). In this study we provide support for demarcation of BFDV strains by phylogenetic analysis of 65 complete genomes from databases and 22 new BFDV sequences isolated from infected psittacines in South Africa. We propose 94% genome-wide sequence identity as a strain demarcation threshold, with isolates sharing > 94% identity belonging to the same strain, and strain subtypes sharing> 98% identity. Currently, BFDV diversity falls within 14 strains, with five highly divergent isolates from budgerigars probably representing a new species of circovirus with three strains (budgerigar circovirus; BCV-A, -B and -C). The geographical distribution of BFDV and BCV strains is strongly linked to the international trade in exotic birds; strains with more than one host are generally located in the same geographical area. Lastly, we examined BFDV and BCV sequences for evidence of recombination, and determined that recombination had occurred in most BFDV and BCV strains. We established that there were two globally significant recombination hotspots in the viral genome: the first is along the entire intergenic region and the second is in the C-terminal portion of the CP ORF. The implications of our results for the taxonomy and classification of circoviruses are discussed. © 2011 SGM.

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Background Dieting has historically been the main behavioural treatment paradigm for overweight/obesity, although a non-dieting paradigm has more recently emerged based on the criticisms of the original dieting approach. There is a dearth of research contrasting why these approaches are adopted. To address this, we conducted a qualitative investigation into the determinants of dieting and non-dieting approaches based on the perspectives and experiences of overweight/obese Australian adults. Methods Grounded theory was used inductively to generate a model of themes contrasting the determinants of dieting and non-dieting approaches based on the perspectives of 21 overweight/obese adults. Data was collected using semi-structured interviews to elicit in-depth individual experiences and perspectives. Results Several categories emerged which distinguished between the adoption of a dieting or non-dieting approach. These categories included the focus of each approach (weight/image or lifestyle/health behaviours); internal or external attributions about dieting failure; attitudes towards established diets, and personal autonomy. Personal autonomy was also influenced by another category; the perceived knowledge and self-efficacy about each approach, with adults more likely to choose an approach they knew more about and were confident in implementing. The time perspective of change (short or long-term) and the perceived identity of the person (fat/dieter or healthy person) also emerged as determinants of dieting or non-dieting approaches respectively. Conclusions The model of determinants elicited from this study assists in understanding why dieting and non-dieting approaches are adopted, from the perspectives and experiences of overweight/obese adults. Understanding this decision-making process can assist clinicians and public health researchers to design and tailor dieting and non-dieting interventions to population subgroups that have preferences and characteristics suitable for each approach.

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Several major human pathogens, including the filoviruses, paramyxoviruses, and rhabdoviruses, package their single-stranded RNA genomes within helical nucleocapsids, which bud through the plasma membrane of the infected cell to release enveloped virions. The virions are often heterogeneous in shape, which makes it difficult to study their structure and assembly mechanisms. We have applied cryo-electron tomography and sub-tomogram averaging methods to derive structures of Marburg virus, a highly pathogenic filovirus, both after release and during assembly within infected cells. The data demonstrate the potential of cryo-electron tomography methods to derive detailed structural information for intermediate steps in biological pathways within intact cells. We describe the location and arrangement of the viral proteins within the virion. We show that the N-terminal domain of the nucleoprotein contains the minimal assembly determinants for a helical nucleocapsid with variable number of proteins per turn. Lobes protruding from alternate interfaces between each nucleoprotein are formed by the C-terminal domain of the nucleoprotein, together with viral proteins VP24 and VP35. Each nucleoprotein packages six RNA bases. The nucleocapsid interacts in an unusual, flexible "Velcro-like" manner with the viral matrix protein VP40. Determination of the structures of assembly intermediates showed that the nucleocapsid has a defined orientation during transport and budding. Together the data show striking architectural homology between the nucleocapsid helix of rhabdoviruses and filoviruses, but unexpected, fundamental differences in the mechanisms by which the nucleocapsids are then assembled together with matrix proteins and initiate membrane envelopment to release infectious virions, suggesting that the viruses have evolved different solutions to these conserved assembly steps.

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We focus on understanding the role of productivity in determining wage structure differences between men and women in academia. The data arise from a pay-equity study carried out in a single Midwestern U.S. university over the 1996–7 academic year. Econometric results confirm that external market forces exert influence over both male and female salary. But peer review ratings play a significant role in male but not female earnings determination, with similar results for objective measures of research, teaching and service.

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A major priority for cancer control agencies is to reduce geographical inequalities in cancer outcomes. While the poorer breast cancer survival among socioeconomically disadvantaged women is well established, few studies have looked at the independent contribution that area- and individual-level factors make to breast cancer survival. Here we examine relationships between geographic remoteness, area-level socioeconomic disadvantage and breast cancer survival after adjustment for patients’ socio- demographic characteristics and stage at diagnosis. Multilevel logistic regression and Markov chain Monte Carlo simulation were used to analyze 18 568 breast cancer cases extracted from the Queensland Cancer Registry for women aged 30 to 70 years diagnosed between 1997 and 2006 from 478 Statistical Local Areas in Queensland, Australia. Independent of individual-level factors, area-level disadvantage was associated with breast-cancer survival (p=0.032). Compared to women in the least disadvantaged quintile (Quintile 5), women diagnosed while resident in one of the remaining four quintiles had significantly worse survival (OR 1.23, 1.27, 1.30, 1.37 for Quintiles 4, 3, 2 and 1 respectively).) Geographic remoteness was not related to lower survival after multivariable adjustment. There was no evidence that the impact of area-level disadvantage varied by geographic remoteness. At the individual level, Indigenous status, blue collar occupations and advanced disease were important predictors of poorer survival. A woman’s survival after a diagnosis of breast cancer depends on the socio-economic characteristics of the area where she lives, independently of her individual-level characteristics. It is crucial that the underlying reasons for these inequalities be identified to appropriately target policies, resources and effective intervention strategies.

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On 3 February 2011, Cyclone Yasi struck the coast of North Queensland, causing widespread damage. The cyclone destroyed the small coastal town of Cardwell, about 165 kilometres north of Townsville, Queensland. This chapter serves as a case study of a collaborative outreach project mobilised in response to this disaster in North Queensland. A public history research team, consisting of practitioners from the Queensland University of Technology’s Creative Industries Faculty, with the support of the Oral History Association of Australia, Queensland branch, partnered with the Cardwell and District Historical Society to support the society to collect community narratives in the wake of Cyclone Yasi.

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This research examines the effects of expectation (perceived attractiveness) on satisfaction, place identity, and place dependence. Place identity and place dependence are viewed as relational components of choice and relate to deeper needs. This study proposes that these two relational components depend on transactional expectations, which are emergent and determined by past experiences and visitor goals. In a theoretically elaborated and tested Structural Equation Model (SEM) this study assumes that these relationships vary according to intentions to return. The study addresses the conditions under which loyalty intentions influence the deeper place attachments (place identity and place dependence) that visitors associate with attractive cultural and natural destinations. The model is tested on a sample of 504 international tourists visiting Tanzania during fall 2010, and explains 59% of variance in the predicted dependent variables. The results are linked to a discussion on loyalty programs.

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Small-angle and ultra-small-angle neutron scattering (SANS and USANS) measurements were performed on samples from the Triassic Montney tight gas reservoir in Western Canada in order to determine the applicability of these techniques for characterizing the full pore size spectrum and to gain insight into the nature of the pore structure and its control on permeability. The subject tight gas reservoir consists of a finely laminated siltstone sequence; extensive cementation and moderate clay content are the primary causes of low permeability. SANS/USANS experiments run at ambient pressure and temperature conditions on lithologically-diverse sub-samples of three core plugs demonstrated that a broad pore size distribution could be interpreted from the data. Two interpretation methods were used to evaluate total porosity, pore size distribution and surface area and the results were compared to independent estimates derived from helium porosimetry (connected porosity) and low-pressure N2 and CO2 adsorption (accessible surface area and pore size distribution). The pore structure of the three samples as interpreted from SANS/USANS is fairly uniform, with small differences in the small-pore range (<2000 Å), possibly related to differences in degree of cementation, and mineralogy, in particular clay content. Total porosity interpreted from USANS/SANS is similar to (but systematically higher than) helium porosities measured on the whole core plug. Both methods were used to estimate the percentage of open porosity expressed here as a ratio of connected porosity, as established from helium adsorption, to the total porosity, as estimated from SANS/USANS techniques. Open porosity appears to control permeability (determined using pressure and pulse-decay techniques), with the highest permeability sample also having the highest percentage of open porosity. Surface area, as calculated from low-pressure N2 and CO2 adsorption, is significantly less than surface area estimates from SANS/USANS, which is due in part to limited accessibility of the gases to all pores. The similarity between N2 and CO2-accessible surface area suggests an absence of microporosity in these samples, which is in agreement with SANS analysis. A core gamma ray profile run on the same core from which the core plug samples were taken correlates to profile permeability measurements run on the slabbed core. This correlation is related to clay content, which possibly controls the percentage of open porosity. Continued study of these effects will prove useful in log-core calibration efforts for tight gas.

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This paper discusses the primacy of communities of practice within learning contexts at university and during practicum for culturally and linguistically diverse preservice teachers. The study illustrates that learning occurs when there are adequate opportunities for participation and practice. Data from interviews with 28 culturally and linguistically diverse preservice teachers illustrate that tensions created by social, cultural differences impact upon modes of identification and dimensions of practice (Lave & Wenger, 1991; Wenger, 1998). The study concludes by reiterating the importance of establishing proactive communities of practice to ensure success in learning and practice for this group of preservice teachers.