824 resultados para Small sample
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Introduction: Research that has focused on the ability of self-report assessment tools to predict crash outcomes has proven to be mixed. As a result, researchers are now beginning to explore whether examining culpability of crash involvement can subsequently improve this predictive efficacy. This study reports on the application of the Manchester Driver Behaviour Questionnaire (DBQ) to predict crash involvement among a sample of general Queensland motorists, and in particular, whether including a crash culpability variable improves predictive outcomes. Surveys were completed by 249 general motorists on-line or via a pen-and-paper format. Results: Consistent with previous research, a factor analysis revealed a three factor solution for the DBQ accounting for 40.5% of the overall variance. However, multivariate analysis using the DBQ revealed little predictive ability of the tool to predict crash involvement. Rather, exposure to the road was found to be predictive of crashes. An analysis into culpability revealed 88 participants reported being “at fault” for their most recent crash. Corresponding between and multi-variate analyses that included the culpability variable did not result in an improvement in identifying those involved in crashes. Conclusions: While preliminary, the results suggest that including crash culpability may not necessarily improve predictive outcomes in self-report methodologies, although it is noted the current small sample size may also have had a deleterious effect on this endeavour. This paper also outlines the need for future research (which also includes official crash and offence outcomes) to better understand the actual contribution of self-report assessment tools, and culpability variables, to understanding and improving road safety.
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Background: Evolution in Australian community pharmacy and general practice environments has seen the emergence of a new opportunity for pharmacist practice, distinct from the conventional community and hospital settings, in which the pharmacist is integrated into the general practice setting to provide professional services. Aim: To characterise pharmacists practising in the Australian general practice setting. Method: An electronic questionnaire. Results: Twenty-six practice pharmacists completed the questionnaire. Practice pharmacists were more likely to be female, aged between 30 and 49 years, have postgraduate qualifications and also work in other pharmacy sectors. The general practice settings more frequently had multiple general practitioners and also housed multiple allied health professionals. The most commonly conducted services provided by the practice pharmacists were Home Medicine Reviews, responding to clinical enquiries from general practitioners and responding to enquiries from other health professionals. Most practice pharmacists worked as independent contractors for services provided. The practice pharmacists provided some services in the absence of remuneration. The majority of practice pharmacists agreed or strongly agreed that a set of competencies should be developed and a credentialing process required with experience of the pharmacist being regarded highly. Conclusion: The results of this study have described the variety of professional roles, remuneration and characteristics in a small sample of pharmacists practising in a general practice setting in Australia. For this model of pharmacist practice to expand an appropriate method of remuneration is required.
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Background: Due to improved screening and treatment for gynaecological cancers survivorship has increased. Use of supportive care services after treatment is important to improve quality of life. Objective: To assess self-reported lower-limb lymphoedema (LLL), depression, anxiety, quality of life, unmet supportive care needs, and service use among gynaecological cancer survivors. Methods: In 2010 a population-based cross-sectional mail survey was conducted (n=160 gynaecological cancer survivors 5 to 30 month post-diagnosis (53% response rate)). Results: Overall, 30% of women self-reported LLL, 21% and 24% depression or anxiety, respectively. Women with LLL were more likely to also report symptoms of depression or anxiety, and with these symptoms had higher unmet supportive care needs. Services needed but not used by 10-15% of women with LLL, anxiety or depression respectively were lymphoedema specialist, pain specialist and physiotherapist, or psychiatrists, psychologists and pain specialists. Limitations: Small sample size, self-report data, limited generalisation to other countries, underrepresentation of older women (age >70) and women from non-Caucasian backgrounds. Conclusions: Women with LLL or high distress were less likely to use services they needed. Funding: This study was funded by Cancer Australia.
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The ability to estimate the expected Remaining Useful Life (RUL) is critical to reduce maintenance costs, operational downtime and safety hazards. In most industries, reliability analysis is based on the Reliability Centred Maintenance (RCM) and lifetime distribution models. In these models, the lifetime of an asset is estimated using failure time data; however, statistically sufficient failure time data are often difficult to attain in practice due to the fixed time-based replacement and the small population of identical assets. When condition indicator data are available in addition to failure time data, one of the alternate approaches to the traditional reliability models is the Condition-Based Maintenance (CBM). The covariate-based hazard modelling is one of CBM approaches. There are a number of covariate-based hazard models; however, little study has been conducted to evaluate the performance of these models in asset life prediction using various condition indicators and data availability. This paper reviews two covariate-based hazard models, Proportional Hazard Model (PHM) and Proportional Covariate Model (PCM). To assess these models’ performance, the expected RUL is compared to the actual RUL. Outcomes demonstrate that both models achieve convincingly good results in RUL prediction; however, PCM has smaller absolute prediction error. In addition, PHM shows over-smoothing tendency compared to PCM in sudden changes of condition data. Moreover, the case studies show PCM is not being biased in the case of small sample size.
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We commend Swanenburg et al. (2013) on translation, development, and clinimetric analysis of the NDI-G. However, the dual-factor structure with factor analysis and the high level of internal consistency (IC) highlighted in their discussion were not emphasized in the abstract or conclusion. These points may imply some inconsistencies with the final conclusions since determination of stable point estimates with the study's small sample are exceedingly difficult.
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Working memory-related brain activation has been widely studied, and impaired activation patterns have been reported for several psychiatric disorders. We investigated whether variation in N-back working memory brain activation is genetically influenced in 60 pairs of twins, (29 monozygotic (MZ), 31 dizygotic (DZ); mean age 24.4 ± 1.7S.D.). Task-related brain response (BOLD percent signal difference of 2 minus 0-back) was measured in three regions of interest. Although statistical power was low due to the small sample size, for middle frontal gyrus, angular gyrus, and supramarginal gyrus, the MZ correlations were, in general, approximately twice those of the DZ pairs, with non-significant heritability estimates (14-30%) in the low-moderate range. Task performance was strongly influenced by genes (57-73%) and highly correlated with cognitive ability (0.44-0.55). This study, which will be expanded over the next 3 years, provides the first support that individual variation in working memory-related brain activation is to some extent influenced by genes.
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The pattern of structural brain alterations associated with major depressive disorder (MDD) remains unresolved. This is in part due to small sample sizes of neuroimaging studies resulting in limited statistical power, disease heterogeneity and the complex interactions between clinical characteristics and brain morphology. To address this, we meta-analyzed three-dimensional brain magnetic resonance imaging data from 1728 MDD patients and 7199 controls from 15 research samples worldwide, to identify subcortical brain volumes that robustly discriminate MDD patients from healthy controls. Relative to controls, patients had significantly lower hippocampal volumes (Cohen’s d=−0.14, % difference=−1.24). This effect was driven by patients with recurrent MDD (Cohen’s d=−0.17, % difference=−1.44), and we detected no differences between first episode patients and controls. Age of onset ⩽21 was associated with a smaller hippocampus (Cohen’s d=−0.20, % difference=−1.85) and a trend toward smaller amygdala (Cohen’s d=−0.11, % difference=−1.23) and larger lateral ventricles (Cohen’s d=0.12, % difference=5.11). Symptom severity at study inclusion was not associated with any regional brain volumes. Sample characteristics such as mean age, proportion of antidepressant users and proportion of remitted patients, and methodological characteristics did not significantly moderate alterations in brain volumes in MDD. Samples with a higher proportion of antipsychotic medication users showed larger caudate volumes in MDD patients compared with controls. This currently largest worldwide effort to identify subcortical brain alterations showed robust smaller hippocampal volumes in MDD patients, moderated by age of onset and first episode versus recurrent episode status.
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It has been 10 years since the seminal paper by Morrison and colleagues reporting the association of alleles of the vitamin D receptor and bone density [1], a paper which arguably kick-started the study of osteoporosis genetics. Since that report there have been literally thousands of osteoporosis genetic studies published, and large numbers of genes have been reported to be associated with the condition [2]. Although some of these reported associations are undoubtedly true, this snow-storm of papers and abstracts has clouded the field to such a great extent that it is very difficult to be certain of the veracity of most genetic associations reported hereto. The field needs to take stock and reconsider the best way forward, taking into account the biology of skeletal development and technological and statistical advances in human genetics, before more effort and money is wasted on continuing a process in which the primary achievement could be said to be a massive paper mountain. I propose in this review that the primary reasons for the paucity of success in osteoporosis genetics has been: •the absence of a major gene effect on bone mineral density (BMD), the most commonly studied bone phenotype; •failure to consider issues such as genetic heterogeneity, gene–environment interaction, and gene–gene interaction; •small sample sizes and over-optimistic data interpretation; and •incomplete assessment of the genetic variation in candidate genes studied.
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Tourism plays an important role in the development of Cook Islands. In this paper we examine the nexus between tourism and growth using quarterly data over the period 2009Q1–2014Q2 using the recently upgraded ARDL bounds test to cointegration tool, Microfit 5.01, which provides sample adjusted bounds and hence is more reliable for small sample size studies. We perform the cointegration using the ARDL bounds test and examine the direction of causality. Using visitor arrival and output in per capita terms as respective proxy for tourism development and growth, we examine the long-run association and report the elasticity coefficient of tourism and causality nexus, accordingly. Using unit root break tests, we note that 2011Q1 and 2011Q2 are two structural break periods in the output series. However, we note that this period is not statistically significant in the ARDL model and hence excluded from the estimation. Subsequently, the regression results show the two series are cointegrated. The long-run elasticity coefficient of tourism is estimated to be 0.83 and the short-run is 0.73. A bidirectional causality between tourism and income is noted for Cook Islands which indicates that tourism development and income mutually reinforce each other. In light of this, socio-economic policies need to focus on broad-based, inclusive and income-generating tourism development projects which are expected to have feedback effect.
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There is limited research on the driving performance and safety of bioptic drivers and even less regarding the driving skills that are most challenging for those learning to drive with bioptic telescopes. This research consisted of case studies of five trainee bioptic drivers whose driving skills were compared with those of a group of licensed bioptic drivers (n = 23) while they drove along city, suburban, and controlled-access highways in an instrumented dual-brake vehicle. A certified driver rehabilitation specialist was positioned in the front passenger seat to monitor safety and two backseat evaluators independently rated driving using a standardized scoring system. Other aspects of performance were assessed through vehicle instrumentation and video recordings. Results demonstrate that while sign recognition, lane keeping, steering steadiness, gap judgments and speed choices were significantly worse in trainees, some driving behaviors and skills, including pedestrian detection and traffic light recognition were not significantly different to those of the licensed drivers. These data provide useful insights into the skill challenges encountered by a small sample of trainee bioptic drivers which, while not generalizable because of the small sample size, provide valuable insights beyond that of previous studies and can be used as a basis to guide training strategies.
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The paper studies stochastic approximation as a technique for bias reduction. The proposed method does not require approximating the bias explicitly, nor does it rely on having independent identically distributed (i.i.d.) data. The method always removes the leading bias term, under very mild conditions, as long as auxiliary samples from distributions with given parameters are available. Expectation and variance of the bias-corrected estimate are given. Examples in sequential clinical trials (non-i.i.d. case), curved exponential models (i.i.d. case) and length-biased sampling (where the estimates are inconsistent) are used to illustrate the applications of the proposed method and its small sample properties.
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We have tested the efficacy of putative microsatellite single sequence repeat (SSR) markers, previously identified in a 2-49 (Gluyas Early/Gala) × Janz doubled haploid wheat (Triticum aestivum) population, as being linked to partial seedling resistance to crown rot disease caused by Fusarium pseudograminearum. The quantitative trait loci (QTLs) delineated by these markers have been tested for linkage to resistance in an independent Gluyas Early × Janz doubled haploid population. The presence of a major QTL on chromosome 1DL (QCr.usq-1D1) and a minor QTL on chromosome 2BS (QCr.usq-2B1) was confirmed. However, a putative minor QTL on chromosome 2A was not confirmed. The QTL on 1D was inherited from Gluyas Early, a direct parent of 2-49, whereas the 2B QTL was inherited from Janz. Three other putative QTLs identified in 2-49 × Janz (on 1AL, 4BL, and 7BS) were inherited by 2-49 from Gala and were not able to be confirmed in this study. The screening of SSR markers on a small sample of elite wheat genotypes indicated that not all of the most tightly linked SSR markers flanking the major QTLs on 1D and 1A were polymorphic in all backgrounds, indicating the need for additional flanking markers when backcrossing into some elite pedigrees. Comparison of SSR haplotypes with those of other genotypes exhibiting partial crown rot resistance suggests that additional, novel sources of crown rot resistance are available.
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Various reasons, such as ethical issues in maintaining blood resources, growing costs, and strict requirements for safe blood, have increased the pressure for efficient use of resources in blood banking. The competence of blood establishments can be characterized by their ability to predict the volume of blood collection to be able to provide cellular blood components in a timely manner as dictated by hospital demand. The stochastically varying clinical need for platelets (PLTs) sets a specific challenge for balancing supply with requests. Labour has been proven a primary cost-driver and should be managed efficiently. International comparisons of blood banking could recognize inefficiencies and allow reallocation of resources. Seventeen blood centres from 10 countries in continental Europe, Great Britain, and Scandinavia participated in this study. The centres were national institutes (5), parts of the local Red Cross organisation (5), or integrated into university hospitals (7). This study focused on the departments of blood component preparation of the centres. The data were obtained retrospectively by computerized questionnaires completed via Internet for the years 2000-2002. The data were used in four original articles (numbered I through IV) that form the basis of this thesis. Non-parametric data envelopment analysis (DEA, II-IV) was applied to evaluate and compare the relative efficiency of blood component preparation. Several models were created using different input and output combinations. The focus of comparisons was on the technical efficiency (II-III) and the labour efficiency (I, IV). An empirical cost model was tested to evaluate the cost efficiency (IV). Purchasing power parities (PPP, IV) were used to adjust the costs of the working hours and to make the costs comparable among countries. The total annual number of whole blood (WB) collections varied from 8,880 to 290,352 in the centres (I). Significant variation was also observed in the annual volume of produced red blood cells (RBCs) and PLTs. The annual number of PLTs produced by any method varied from 2,788 to 104,622 units. In 2002, 73% of all PLTs were produced by the buffy coat (BC) method, 23% by aphaeresis and 4% by the platelet-rich plasma (PRP) method. The annual discard rate of PLTs varied from 3.9% to 31%. The mean discard rate (13%) remained in the same range throughout the study period and demonstrated similar levels and variation in 2003-2004 according to a specific follow-up question (14%, range 3.8%-24%). The annual PLT discard rates were, to some extent, associated with production volumes. The mean RBC discard rate was 4.5% (range 0.2%-7.7%). Technical efficiency showed marked variation (median 60%, range 41%-100%) among the centres (II). Compared to the efficient departments, the inefficient departments used excess labour resources (and probably) production equipment to produce RBCs and PLTs. Technical efficiency tended to be higher when the (theoretical) proportion of lost WB collections (total RBC+PLT loss) from all collections was low (III). The labour efficiency varied remarkably, from 25% to 100% (median 47%) when working hours were the only input (IV). Using the estimated total costs as the input (cost efficiency) revealed an even greater variation (13%-100%) and overall lower efficiency level compared to labour only as the input. In cost efficiency only, the savings potential (observed inefficiency) was more than 50% in 10 departments, whereas labour and cost savings potentials were both more than 50% in six departments. The association between department size and efficiency (scale efficiency) could not be verified statistically in the small sample. In conclusion, international evaluation of the technical efficiency in component preparation departments revealed remarkable variation. A suboptimal combination of manpower and production output levels was the major cause of inefficiency, and the efficiency did not directly relate to production volume. Evaluation of the reasons for discarding components may offer a novel approach to study efficiency. DEA was proven applicable in analyses including various factors as inputs and outputs. This study suggests that analytical models can be developed to serve as indicators of technical efficiency and promote improvements in the management of limited resources. The work also demonstrates the importance of integrating efficiency analysis into international comparisons of blood banking.
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Social audit is one of those important mechanisms for strengthening NGOs’ accountability to poor communities (as NGOs’ key beneficiaries). However, conducting social audits within the NGO sector often rests on the individual interests and priorities of donors or NGOs themselves, effectively resulting in self-selection bias, and limiting the effectiveness and usefulness of social audits as a control and evaluation mechanism. The purpose of this chapter is to identify the prevalence, scale, and scope of social audits within the NGO sector, particularly NGOs engaging in microenterprise development programs. Accordingly, this study examined 20 NGOs operating in two countries - Bangladesh and Indonesia. Data were collected from publicly available sources and in-depth interviews with senior executives of the participating NGOs. Further, 10 interviews were conducted with a small sample of beneficiaries (individuals or groups from four of the participating NGOs) in order to gain an understanding of beneficiaries’ perceptions of the NGOs’ social audit mechanism. The findings reveal a range of approaches to social audit among NGOs, as well as the usefulness and limitations of this mechanism for strengthening NGO accountability, particularly to beneficiaries. Findings highlight that within the NGOs investigated the conduct of social audits remained voluntary and was strongly dependant on donors’ requirements. As social audit regulation within the NGO sector is minimal, the findings provide regulators with valuable guidance for better understanding the value of social audit as a mechanism to strengthen accountability of the NGO sector, particularly accountability to beneficiaries.
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Purpose The purpose of this paper is to report the first empirical test of the recently proposed ambidexterity theory of leadership for innovation (Rosing et al., 2011). This theory proposes that the interaction between two complementary leadership behaviors – opening and closing – predicts team innovation, such that team innovation is highest when both opening and closing leadership behaviors are high. Design/methodology/approach Multi-source survey data came from 33 team leaders of architectural and interior design firms and 90 of their employees. Findings Results supported the interaction hypothesis, even after controlling for leaders’ transformational leadership behavior and general team success. Research limitations/implications The relatively small sample size and the cross-sectional design are potential limitations of the study. The findings provide initial support for the central hypothesis of the ambidexterity theory of leadership for innovation. Practical implications The results suggest that organizations could train team leaders’ ambidextrous leadership behaviors to increase team innovation. Social implications Identifying ways to facilitate organizational innovation is important, as it contributes to employment and company growth as well as individual and societal well-being. Originality/value This multi-source study contributes to the literatures on leadership and innovation in organizations by showing that ambidextrous leadership behaviors predict team innovation above and beyond transformational leadership behavior.