Evaluation of fixed sample-size plans for Plutella xylostella (Lepidoptera: Plutellidae) on broccoli crops in Australia

Fixed sample-size plans for monitoring Plutella xylostella (L.) (Lepidoptera: Plutellidae) on broccoli and other Brassica vegetable crops are popular in Australia for their simplicity and ease of application. But the sample sizes used are often small, ≈10–25 plants per crop, and it may be that they fail to provide sufficient information upon which to base pest control decisions. We tested the performance of seven fixed sample-size plans (10, 15, 20, 30, 35, 40, and 45 plants) by resampling a large data set on P. xylostella in commercial broccoli crops. For each sample size, enumerative and presence-absence plans were assessed. The precision of the plans was assessed in terms of the ratio of the standard error to the mean; and at least 45 and 35 samples were necessary for the enumerative and presence-absence plans, respectively, to attain the generally accepted benchmark of ≤0.3. Sample sizes of 10–20 were highly imprecise. We also assessed the consequences of classifications based on action thresholds (ATs) of 0.2 and 0.8 larvae per plant for the enumerative case, and 0.15 and 0.45 proportion of plants of infested for the presence-absence case. Operating characteristic curves and investigations of the frequency of correct decisions suggest improvements in the performance of plans with increased sample size. In both the enumerative and presence-absence cases, the proportion of incorrect decisions was much higher for the lower of the two ATs assessed, and type II errors (i.e., failure to suggest pest control upon the AT is exceeded) generally accounted for the majority of this error. Type II errors are the most significant from a producer’s standpoint. Further consideration is necessary to determine what is an acceptable type II error rate.

Womens satisfaction with their breast prosthesis: What determines a quality prosthesis

The aim of this study is to determine what factors constitute a quality prosthesis and ascertain which factors affect prosthesis satisfaction. Sixty-four women who received full funding for their prosthesis and 38 women who received their hospital’s usual fundingwere recruited. Women rated the information provided about breast prostheses very highly, with 85% reporting that it was "very good" or "excellent." Satisfaction was significantly associatedwith how well the prosthesis fit (1 week,p=.001; 3 months,p=.01), level of comfort (3 months,p=.005), and appearance of the prosthesis when worn (6 months,p = .001). Quality was significantly associated with how well it fit (1 week,p = .001; 3months,p = .001), how natural it felt (1 week,p = .001; 6months,p=.01), the weight of the prosthesis (3 months,p=.003), and appearance when worn (6 months,p = .03). The results will be used to improve women’s access to a quality prosthesis.

External breast prosthesis use: experiences and views of women with breast cancer, breast care nurses, and prosthesis fitters

After mastectomy, the provision of an appropriate breast prosthesis can help to improve body image and quality of life and reduce associated emotional distress. Although up to 90% of women use an external breast prosthesis after mastectomy, little is known about their experiences and satisfaction with breast prosthesis use. Focus groups were conducted with women who had been fitted with an external breast prosthesis, breast care nurses, and prosthesis fitters to explore women's experiences of prosthesis use. Qualitative thematic content analysis of focus group transcripts indicated that whereas women's initial reaction to the prosthesis generally was negative, this improved over time. Provision of adequate information and support, characteristics of the fitter and the fitting experience, and relationships with breast care nurses and prosthesis fitters were important to women's acceptance and satisfaction with their prosthesis. The study results highlighted the key role that breast care nurses play and the underestimation of the prosthesis fitter's role. Common themes concerning the impact of prosthesis use included body image, appearance, and feminine identity. These findings have important implications for professionals involved in the delivery of breast prostheses services.

Fixed and floating charges : the latest conflicting law and how to address the gaps

Can book debts be subject to a fixed charge? This question was considered by the House of Lords in National Westminster Bank v. Spectrum Plus Limited [2005] UKHL 41 where the full House was against the idea of a fixed charge on book debts and insisted that only a floating charge had been created. The law in this area is still vague and uncertain in Australia. This paper argues that the financiers and the companies should be given the freedom to decide how they wish to structure their charge documents. The paper sets out to argue that, in respect to the use of book debts as security for a loan, the only way for both the financiers and the companies to do business is to create a sustained workable fixed charge or even multiple fixed and floating charge on book debts. The author explains how this could be possible and how the proposed model would not deny the statutory priority rights of the preferential creditors.

Sequential fixed-width confidence bands for kernel regression estimation

We consider a random design model based on independent and identically distributed (iid) pairs of observations (Xi, Yi), where the regression function m(x) is given by m(x) = E(Yi|Xi = x) with one independent variable. In a nonparametric setting the aim is to produce a reasonable approximation to the unknown function m(x) when we have no precise information about the form of the true density, f(x) of X. We describe an estimation procedure of non-parametric regression model at a given point by some appropriately constructed fixed-width (2d) confidence interval with the confidence coefficient of at least 1−. Here, d(> 0) and 2 (0, 1) are two preassigned values. Fixed-width confidence intervals are developed using both Nadaraya-Watson and local linear kernel estimators of nonparametric regression with data-driven bandwidths.

The sample size was optimized using the purely and two-stage sequential procedure together with asymptotic properties of the Nadaraya-Watson and local linear estimators. A large scale simulation study was performed to compare their coverage accuracy. The numerical results indicate that the confidence bands based on the local linear estimator have the best performance than those constructed by using Nadaraya-Watson estimator. However both estimators are shown to have asymptotically correct coverage properties.

Sample size determination for kernel regression estimation using sequential fixed-width confidence bands

We consider a random design model based on independent and identically distributed pairs of observations (Xi, Yi), where the regression function m(x) is given by m(x) = E(Yi|Xi = x) with one independent variable. In a nonparametric setting the aim is to produce a reasonable approximation to the unknown function m(x) when we have no precise information about the form of the true density, f(x) of X. We describe an estimation procedure of non-parametric regression model at a given point by some appropriately constructed fixed-width (2d) confidence interval with the confidence coefficient of at least 1−. Here, d(> 0) and 2 (0, 1) are two preassigned values. Fixed-width confidence intervals are developed using both Nadaraya-Watson and local linear kernel estimators of nonparametric regression with data-driven bandwidths. The sample size was optimized using the purely and two-stage sequential procedures together with asymptotic properties of the Nadaraya-Watson and local linear estimators. A large scale simulation study was performed to compare their coverage accuracy. The numerical results indicate that the confi dence bands based on the local linear estimator have the better performance than those constructed by using Nadaraya-Watson estimator. However both estimators are shown to have asymptotically correct coverage properties.

A novel monotonic fixed-point algorithm for l1-regularized least square vector and matrix problem

Least square problem with l₁ regularization has been proposed as a promising method for sparse signal reconstruction (e.g., basis pursuit de-noising and compressed sensing) and feature selection (e.g., the Lasso algorithm) in signal processing, statistics, and related fields. These problems can be cast as l₁-regularized least-square program (LSP). In this paper, we propose a novel monotonic fixed point method to solve large-scale l₁-regularized LSP. And we also prove the stability and convergence of the proposed method. Furthermore we generalize this method to least square matrix problem and apply it in nonnegative matrix factorization (NMF). The method is illustrated on sparse signal reconstruction, partner recognition and blind source separation problems, and the method tends to convergent faster and sparser than other l₁-regularized algorithms.

Fixed-angle locking proximal humerus plate: an evaluation of functional results and implant-related outcomes

Background
Displaced and unstable proximal humeral fractures are challenging injuries to treat. Proximal humeral locking plates are a recent development for the treatment of these complex fractures.

Methods
Retrospective analysis of 23 patients with 23 proximal humeral fractures treated with the Synthes locking proximal humerus plate. These were Neer two-, three- and four-part fractures. Follow-up was at a mean of 22 months and included clinical assessment using the Constant score (CS) and the Short Form-12 health questionnaire. Radiographic assessment was performed to assess implant-related complication in relation to the initial fracture pattern and the presence of adequate medial support.

Results
The mean CS for all patients was 60.4 (range, 29–85). The mean adjusted CS was 82% (range, 30–117), active forward flexion 127 degrees and the active abduction 115 degrees. Initial fracture pattern, the presence or absence of adequate medial support and age did not significantly influence the clinical scores. Complications included one infection, two cases of avascular necrosis, two cases of varus collapse with screw penetration and one non-union. The overall reoperation rate was 26%. There was an increased rate of complications in those with inadequate medial support (P = 0.0183) and a trend to higher complication rates in four-part fractures.

Conclusion
Using the locking proximal humerus plate for the treatment of proximal humeral fractures is an acceptable procedure with comparable outcomes with historical controls, but with a complication rate of 30%. More important than implant selection, however, is the ability to achieve a stable reduction with calcar support.

Does disability status modify the association between psychosocial job quality and mental health? A longitudinal fixed-effects analysis

BACKGROUND: People with disabilities have difficulties in obtaining work. However, evidence suggests that those with disabilities derive substantial mental health benefits from employment. This paper assesses how the relationship between work and mental health is influenced by psychosocial job quality for people working with a disability. METHODS: The study design was a longitudinal cohort with 13 annual waves of data collection, yielding a sample of 122,883 observations from 21,848 people. Fixed-effects within-person regression was used to control for time invariant confounding. The Mental Component Summary (MCS) of the Short Form 36 (SF-36) measure was used as the primary outcome measure. The main exposure was a six-category measure of psychosocial job quality and employment status (including 'not in the labour force' [NILF] and unemployment). Disability status ('no waves of disability reported' and 'all contributed waves with reported disability') was assessed as an effect modifier. We also conducted a secondary analysis on respondents contributing both disability and non-disability waves. RESULTS: For those with no disability, the greatest difference in mental health (compared to optimal employment) occurs when people have the poorest quality jobs (-2.12, 95% CI -2.48, -1.75, p < 0.001). The relative difference in mental health was less in relation to NILF and unemployment (-0.39 and -0.66 respectively). For those with consistent disability, the difference in mental health when employed in an optimal job was similar between the poorest quality jobs (-2.25, 95% CI -3.84, -0.65, p = 0.006), NILF (-2.84, 95% CI -4.49, -1.20, p = 0.001) or unemployment (-2.56, 95% CI -4.32, -0.80, p = 0.004). These results were confirmed by the secondary analysis. CONCLUSIONS: Efforts to improve psychosocial job quality may have significant mental health benefits for people with disabilities. This will contribute to the economic viability of disability employment insurance schemes in Australia and other high-income countries.