Showing papers by "La Trobe University published in 2000"

Y-Chromosomal Diversity in Europe Is Clinal and Influenced Primarily by Geography, Rather than by Language

Abstract: Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups, to analyze a sample of 3,616 Y chromosomes belonging to 47 European and circum-European populations. Patterns of geographic differentiation are highly nonrandom, and, when they are assessed using spatial autocorrelation analysis, they show significant clines for five of six haplogroups analyzed. Clines for two haplogroups, representing 45% of the chromosomes, are continentwide and consistent with the demic diffusion hypothesis. Clines for three other haplogroups each have different foci and are more regionally restricted and are likely to reflect distinct population movements, including one from north of the Black Sea. Principal-components analysis suggests that populations are related primarily on the basis of geography, rather than on the basis of linguistic affinity. This is confirmed in Mantel tests, which show a strong and highly significant partial correlation between genetics and geography but a low, nonsignificant partial correlation between genetics and language. Genetic-barrier analysis also indicates the primacy of geography in the shaping of patterns of variation. These patterns retain a strong signal of expansion from the Near East but also suggest that the demographic history of Europe has been complex and influenced by other major population movements, as well as by linguistic and geographic heterogeneities and the effects of drift.

Movement Disorders in People With Parkinson Disease: A Model for Physical Therapy

Abstract: People who are diagnosed with idiopathic Parkinson disease (PD) experience movement disorders that, if not managed, can lead to considerable disability. The premise of this perspective is that physical therapy for people with PD relies on clinicians having: (1) up-to-date knowledge of the pathogenesis of movement disorders, (2) the ability to recognize common movement disorders in people with PD, (3) the ability to implement a basic management plan according to a person's stage of disability, and (4) problem-solving skills that enable treatment plans to be tailored to individual needs. This article will present a model of physical therapy management for people with idiopathic PD based on contemporary knowledge of the pathogenesis of movement disorders in basal ganglia disease as well as a review of the evidence for physical therapy interventions. The model advocates a task-specific approach to training, with emphasis on treating people with PD-related movement disorders such as hypokinesia and postural instability within the context of functional tasks of everyday living such as walking, turning over in bed, and manipulating objects. The effects of medication, cognitive impairment, the environment, and coexisting medical conditions are also taken into consideration. An argument is put forward that clinicians need to identify core elements of physical therapy training that apply to all people with PD as well as elements specific to the needs of each individual. A case history is used to illustrate how physical therapy treatment is regularly reviewed and adjusted according to the changing constellation of movement disorders that present as the disease progresses.

A New Chemolithoautotrophic Arsenite-Oxidizing Bacterium Isolated from a Gold Mine: Phylogenetic, Physiological, and Preliminary Biochemical Studies

Abstract: A previously unknown chemolithoautotrophic arsenite-oxidizing bacterium has been isolated from a gold mine in the Northern Territory of Australia. The organism, designated NT-26, was found to be a gram-negative motile rod with two subterminal flagella. In a minimal medium containing only arsenite as the electron donor (5 mM), oxygen as the electron acceptor, and carbon dioxide-bicarbonate as the carbon source, the doubling time for chemolithoautotrophic growth was 7.6 h. Arsenite oxidation was found to be catalyzed by a periplasmic arsenite oxidase (optimum pH, 5.5). Based upon 16S rDNA phylogenetic sequence analysis, NT-26 belongs to the Agrobacterium/Rhizobium branch of the a-Proteobacteria and may represent a new species. This recently discovered organism is the most rapidly growing chemolithoautotrophic arsenite oxidizer known.

Four approaches to capacity building in health: consequences for measurement and accountability

Abstract: SUMMARY The term capacity building has been used in respect of a wide range of strategies and processes which have the ultimate aim of improved health practices which are sustainable. After defining capacity building, this paper explores the processes and strategies associated with four distinct approaches to capacity building, considers the role of funding bodies and begins to question how these factors impact on the evaluation of capacity building.

Probability Density Function Estimation Using Gamma Kernels

Abstract: We consider estimating density functions which have support on [0, ∞) using some gamma probability densities as kernels to replace the fixed and symmetric kernel used in the standard kernel density estimator. The gamma kernels are non-negative and have naturally varying shape. The gamma kernel estimators are free of boundary bias, non-negative and achieve the optimal rate of convergence for the mean integrated squared error. The variance of the gamma kernel estimators at a distance x away from the origin is O(n−4/5x−1/2) indicating a smaller variance as x increases. Finite sample comparisons with other boundary bias free kernel estimators are made via simulation to evaluate the performance of the gamma kernel estimators.

Work-related musculoskeletal disorders in physical therapists : prevalence, severity, risks, and Responses.

Abstract: Background and Purpose Physical therapists are at risk for work-related musculoskeletal disorders (WMSDs) Little is known of how therapists respond to injury or of what actions they take to prevent injury The purpose of this study was to investigate the prevalence and severity of WMSDs in physical therapists, contributing risk factors, and their responses to injury Subjects As part of a larger study, a systematic sample of 1 in 4 therapists on a state register (n=824) was surveyed Methods An 8-page questionnaire was mailed to each subject Questions investigated musculoskeletal symptoms, specialty areas, tasks and job-related risk factors, injury prevention strategies, and responses to injury Results Lifetime prevalence of WMSDs was 91%, and 1 in 6 physical therapists moved within or left the profession as a result of WMSDs Younger therapists reported a higher prevalence of WMSDs in most body areas Use of mobilization and manipulation techniques was related to increased prevalence of thumb symptoms Risk factors pertaining to workload were related to a higher prevalence of neck and upper-limb symptoms, and postural risk factors were related to a higher prevalence of spinal symptoms Conclusion and Discussion Strategies used to reduce work-related injury in industry may also apply to physical therapists Increased risk of thumb symptoms associated with mobilization techniques suggests that further research is needed to establish recommendations for practice The issues for therapists who move within or leave the profession are unknown, and further research is needed to better understand their needs and experiences

Explanation and Cognition

Abstract: Explanations seem to be a large and natural part of our cognitive lives. As Frank Keil and Robert Wilson write, "When a cognitive activity is so ubiquitous that it is expressed both in a preschooler's idle questions and in work that is the culmination of decades of scholarly effort, one has to ask whether we really have one and the same phenomenon or merely different cognitively based phenomena that are loosely, or even metaphorically, related." This book is unusual in its interdisciplinary approach to that ubiquitous activity. The essays address five basic questions about explanation: How do explanatory capacities develop? Are there kinds of explanation? Do explanations correspond to domains of knowledge? Why do we seek explanations, and what do they accomplish? How central are causes to explanation? The essays draw on work in the history and philosophy of science, the philosophy of mind and language, the development of concepts in children, conceptual change in adults, and reasoning in human and artificial systems. They also introduce emerging perspectives on explanation from computer science, linguistics, and anthropology. Contributors: Woo-kyoung Ahn, William F. Brewer, Patricia W. Cheng, Clark A. Chinn, Andy Clark, Robert Cummins, Clark Glymour, Alison Gopnik, Christine Johnson, Charles W. Kalish, Frank C. Keil, Robert N. McCauley, Gregory L. Murphy, Ala Samarapungavan, Herbert A. Simon, Paul Thagard, Robert A. Wilson.

A protein complex containing Tho2, Hpr1, Mft1 and a novel protein, Thp2, connects transcription elongation with mitotic recombination in Saccharomyces cerevisiae

Abstract: Transcription‐induced recombination has been reported in all organisms from bacteria to mammals. We have shown previously that the yeast genes HPR1 and THO2 may be keys to the understanding of transcription‐associated recombination, as they both affect transcription elongation and hyper‐recombination in a concerted manner. Using a yeast strain that has the wild‐type THO2 gene replaced by one encoding a His 6 ‐HA‐tagged version, we have isolated an oligomeric complex containing four proteins: Tho2, Hpr1, Mft1 and a novel protein that we have named Thp2. We have reciprocally identified a complex containing Hpr1, Tho2 and Mft1 using anti‐Mft1 antibodies in immunoprecipitation experiments. The protein complex is mainly nuclear; therefore, Tho2 and Hpr1 are physically associated. Like hpr1Δ and tho2Δ cells, mft1Δ and thp2Δ cells show mitotic hyper‐ recombination and impaired transcription elongation, in particular, through the bacterial lacZ sequence. Hyper‐recombination conferred by mft1Δ and thp2Δ is only observed in DNA regions under transcription conditions. We propose that this protein complex acts as a functional unit connecting transcription elongation with the incidence of mitotic recombination.

Growth of filamentous fungi in submerged culture: problems and possible solutions

Abstract: Filamentous fungi are important organisms industrially and continue to attract research interest as microbiologists attempt to overcome the problems associated with their behavior in submerged culture. This review critically examines the literature describing these problems and where available suggests possible solutions to them. The influence of the chemical and physical environment on culture morphology, the process engineering challenges presented by different fungal morphologies, and the relationship between fungal morphology and metabolite production are all discussed.

Team mental models: techniques, methods, and analytic approaches.

Abstract: Effective team functioning requires the existence of a shared or team mental model among members of a team However, the best method for measuring team mental models is unclear Methods reported vary in terms of how mental model content is elicited and analyzed or represented We review the strengths and weaknesses of vatrious methods that have been used to elicit, represent, and analyze individual and team mental models and provide recommendations for method selection and development We describe the nature of mental models and review techniques that have been used to elicit and represent them We focus on a case study on selecting a method to examine team mental models in industry The processes involved in the selection and development of an appropriate method for eliciting, representing, and analyzing team mental models are described The criteria for method selection were (a) applicability to the problem under investigation; (b) practical considerations - suitability for collecting data from the targeted research sample; and (c) theoretical rationale - the assumption that associative networks in memory are a basis for the development of mental models We provide an evaluation of the method matched to the research problem and make recommendations for future research The practical applications of this research include the provision of a technique for analyzing team mental models in organizations, the development of methods and processes for eliciting a mental model from research participants in their normal work environment, and a survey of available methodologies for mental model research

Phosphoglycerate kinase acts in tumour angiogenesis as a disulphide reductase.

Abstract: Disulphide bonds in secreted proteins are considered to be inert because of the oxidizing nature of the extracellular milieu An exception to this rule is a reductase secreted by tumour cells that reduces disulphide bonds in the serine proteinase plasmin1,2 Reduction of plasmin initiates proteolytic cleavage in the kringle 5 domain and release of the tumour blood vessel inhibitor angiostatin3 New blood vessel formation or angiogenesis is critical for tumour expansion and metastasis4,5 Here we show that the plasmin reductase isolated from conditioned medium of fibrosarcoma cells is the glycolytic enzyme phosphoglycerate kinase6 Recombinant phosphoglycerate kinase had the same specific activity as the fibrosarcoma-derived protein Plasma of mice bearing fibrosarcoma tumours contained several-fold more phosphoglycerate kinase, as compared with mice without tumours Administration of phosphoglycerate kinase to tumour-bearing mice caused an increase in plasma levels of angiostatin, and a decrease in tumour vascularity and rate of tumour growth Our findings indicate that phosphoglycerate kinase not only functions in glycolysis but is secreted by tumour cells and participates in the angiogenic process as a disulphide reductase

Laboratory selection experiments using Drosophila: what do they really tell us?

Abstract: Laboratory selection experiments using Drosophila, and other organisms, are widely used in experimental biology. In particular, such experiments on D. melanogaster life history and stress-related traits have been instrumental in developing the emerging field of experimental evolution. However, similar selection experiments often produce inconsistent correlated responses to selection. Unfortunately, selection experiments are vulnerable to artifacts that are difficult to control. In spite of these problems, selection experiments are a valuable research tool and can contribute to our understanding of evolution in natural populations.

Evolution and Structure of the Lachlan Fold Belt (Orogen) of Eastern Australia

Abstract: The Lachlan Fold Belt (Lachlan Orogen) of eastern Australia was part of a Paleozoic convergent plate margin that stretched around the supercontinent of Gondwana from South America to Australia. Lower Paleozoic (545–365 Ma) deep-water, quartz-rich turbidites, calcalkaline volcanic rocks, and voluminous granitic plutons dominate the Lachlan Orogen. These rocks overlie a mafic lower crust of oceanic affinity. Shortening and accretion of the Lachlan occurred through stepwise deformation and metamorphism from Late Ordovician (∼450 Ma) through early Carboniferous times, with dominant events at about 440–430 Ma and 400–380 Ma. The development and accretion of the Lachlan Orogen and other related belts within the Tasmanides added about 2.5 Mkm2 to the surface area of Gondwana. The sedimentary, magmatic, and deformational processes converted an oceanic turbidite fan system into continental crust of normal thickness. The addition of this recycled continental detritus and juvenile material to Australia represents an...

Voice characteristics in the progression of Parkinson’s disease

Abstract: This study examined the acoustic and perceptual voice characteristics of patients with Parkinson's disease according to disease severity. The perceptual and acoustic voice characteristics of 30 patients with early stage PD and 30 patients with later stage PD were compared with data from 30 normal control subjects. Voice recordings consisted of prolongation of the vowel /a/, scale singing, and a 1-min monologue. In comparison with controls and previously published normative data, both early and later stage PD patients' voices were characterized perceptually by limited pitch and loudness variability, breathiness, harshness and reduced loudness. High modal pitch levels also characterized the voices of males in both early and later stages of PD. Acoustically, the voices of both groups of PD patients demonstrated lower mean intensity levels and reduced maximum phonational frequency ranges in comparison with normative data. Although less clear, the present data also suggested that the PD patients' voices were characterized by excess jitter, a high-speaking fundamental frequency for males and a reduced fundamental frequency variability for females. While several of these voice features did not appear to deteriorate with disease progression (i.e. harshness, high modal pitch and speaking fundamental frequency in males, fundamental frequency variability in females, low intensity and jitter), breathiness, monopitch and monoloudness, low loudness and reduced maximum phonational frequency range were all worse in the later stages of PD. Tremor was the sole voice feature which was associated only with later stage PD.

Can simultaneous bilateral movement involve the undamaged hemisphere in reconstruction of neural networks damaged by stroke

Abstract: Normalization of upper limb movement remains a difficult problem for a significant subpopulation of hemiplegic stroke patients. Clinical observations prompted investigation of a novel approach using simultaneous identical bilateral movements performed independently. We briefly report 12 controlled single-case experiments using multiple-baseline designs across three separate grasp/reach activities. Unilateral performance tests with the hemiplegic arm using the bilaterally trained actions demonstrated clinically and statistically significant improvements in movement patterns. These improvements were specific to the trained movement and well maintained. Using recent literature we develop a theoretical model proposing that bilateral simultaneous movement promotes interhemispheric disinhibition likely to allow reorganization by sharing of normal movement commands from the undamaged hemisphere. Disinhibition may also encourage recruitment of undamaged neurones to construct new task-relevant neural networks. The...

A customer‐service worker relationship model

Abstract: True loyalty, defined by a high relative attitude in addition to high repeat purchase, is an extremely valuable asset to the service firm – as the customer’s search motivation for competitive alternatives is reduced, he/she shows an immunity to the pull of competition and provides favourable word of mouth. A conceptual model presents the likely influence of customer relationships with service workers on the development of true customer loyalty to the service firm. It is suggested that strong customer relationships with a firm’s service personnel lead to true customer loyalty to the service firm, as positive attitudes towards service staff are transferred directly to the firm. In situations where a strong relationship develops between the customer and only one particular service worker, true loyalty to the service firm will be an outcome of high personal loyalty and therefore be dependent on the continued availability of the service worker. To assist managers in encouraging relationship development between...

Randomised controlled trial of midwife led debriefing to reduce maternal depression after operative childbirth

Abstract: Objective: To assess the effectiveness of a midwife led debriefing session during the postpartum hospital stay in reducing the prevalence of maternal depression at six months postpartum among women giving birth by caesarean section, forceps, or vacuum extraction. Design: Randomised controlled trial. Setting: Large maternity teaching hospital in Melbourne, Australia. Participants: 1041 women who had given birth by caesarean section (n= 624) or with the use of forceps (n= 353) or vacuum extraction (n= 64). Main outcome measures: Maternal depression (score ≥13 on the Edinburgh postnatal depression scale) and overall health status (comparison of mean scores on SF-36 subscales) measured by postal questionnaire at six months postpartum. Results: 917 (88%) of the women recruited responded to the outcome questionnaire. More women allocated to debriefing scored as depressed six months after birth than women allocated to usual postpartum care (81 (17%) v 65 (14%)), although this difference was not significant (odds ratio=1.24, 95% confidence interval 0.87 to 1.77). They were also more likely to report that depression had been a problem for them since the birth, but the difference was not significant (123 (28%) v 94 (22%); odds ratio=1.37, 1.00 to 1.86). Women allocated to debriefing had poorer health status on seven of the eight SF-36 subscales, although the difference was significant only for role functioning (emotional): mean scores 73.32 v 78.98, t= −2.31, 95% confidence interval −10.48 to −0.84). Conclusions: Midwife led debriefing after operative birth is ineffective in reducing maternal morbidity at six months postpartum. The possibility that debriefing contributed to emotional health problems for some women cannot be excluded.

What university teachers teach and how they teach it

Abstract: In this chapter we make three related arguments. The first, is that different teachers have different intentions concerning what students will learn and consequently in their teaching they constitute the topic or subject to be taught quite differently. The second is that a teacher’s intentions concerning what it is that students should learn is closely aligned with a teacher’s expectation of how students learn and how they can be helped to learn through teaching. The third is that when teachers focus specifically on the teaching of a particular topic within a specific context, there is a close relationship between their intentions and their teaching practice. In this chapter we explore these arguments through an empirical study which considers the different ways in which 26 university teachers intended to constitute a subject or topic for their students to study, how they then taught the subject and subsequently how consistent were their intentions and their practice. The analysis shows that when the context of teaching and learning is tightly defined there is a clear relationship between a teacher’s intention and their practice. In particular, university teachers who adopt more conceptual change and student-focussed approaches to teaching constitute objects of study which are more relational and focus on the student’s knowledge.

Do executive function deficits differentiate between adolescents with ADHD and oppositional defiant/conduct disorder? A neuropsychological study using the Six Elements Test and Hayling Sentence Completion Test.

Abstract: Two neuropsychological measures of executive functions--Six Elements Tests (SET) and Hayling Sentence Completion Test (HSCT)--were administered to 110 adolescents, aged 12-15 years. Participants comprised four groups: Attention Deficit Hyperactivity Disorder (ADHD) only (n = 35). ADHD and Oppositional Defiant Disorder/Conduct Disorder (ODD/CD) (n = 38), ODD/CD only (n = 11), and a normal community control group (n = 26). Results indicated that adolescents with ADHD performed significantly worse on both the SET and HSCT than those without ADHD, whether or not they also had ODD/CD. The adolescents with ADHD and with comorbid ADHD and ODD/CD were significantly more impaired in their ability to generate strategies and to monitor their ongoing behavior compared with age-matched controls and adolescents with ODD/CD only. It is argued that among adolescents with clinically significant levels of externalizing behavior problems, executive function deficits are specific to those with ADHD. The findings support the sensitivity of these two relatively new tests of executive functions and their ecological validity in tapping into everyday situations, which are potentially problematic for individuals with ADHD.

Two new arsenate/sulfate-reducing bacteria : mechanisms of arsenate reduction

Abstract: Two sulfate-reducing bacteria, which also reduce arsenate, were isolated; both organisms oxidized lactate incompletely to acetate. When using lactate as the electron donor, one of these organisms, Desulfomicrobium strain Ben-RB, rapidly reduced (doubling time = 8 h) 5.1 mM arsenate at the same time it reduced sulfate (9.6 mM). Sulfate reduction was not inhibited by the presence of arsenate. Arsenate could act as the terminal electron acceptor in minimal medium (doubling time = 9 h) in the absence of sulfate. Arsenate was reduced by a membrane-bound enzyme that is either a c-type cytochrome or is associated with such a cytochrome; benzyl-viologen-dependent arsenate reductase activity was greater in cells grown with arsenate/sulfate than in cells grown with sulfate only. The second organism, Desulfovibrio strain Ben-RA, also grew (doubling time = 8 h) while reducing arsenate (3.1 mM) and sulfate (8.3 mM) concomitantly. No evidence was found, however, that this organism is able to grow using arsenate as the terminal electron acceptor. Instead, it appears that arsenate reduction by the Desulfovibrio strain Ben-RA is catalyzed by an arsenate reductase that is encoded by a chromosomally-borne gene shown to be homologous to the arsC gene of the Escherichia coli plasmid, R773 ars system.

An optimized method for estimating intracranial volume from magnetic resonance images

Abstract: The accuracy and efficiency of protocols to measure intracranial volume (ICV) from volumetric magnetic resonance imaging (MRI) studies has not been formally analyzed. The ICV of 30 control participants was obtained by tracing every slice of a MRI data set on which the cranial cavity appeared, and compared with estimated ICVs calculated by progressively selecting one of every x slices (i.e., "1-in-x") as a sampling strategy. The reliability and precision of each sampling strategy was then determined. There was virtually no reduction in reliability at the 1-in-10 sampling strategy, with a reliability exceeding 0.999. ICV can be confidently traced using a 1-in-10 sampling strategy, which should result in significant time savings.