Improving statistical analysis of matched case-control studies

Matched case–control research designs can be useful because matching can increase power due to reduced variability between subjects. However, inappropriate statistical analysis of matched data could result in a change in the strength of association between the dependent and independent variables or a change in the significance of the findings. We sought to ascertain whether matched case–control studies published in the nursing literature utilized appropriate statistical analyses. Of 41 articles identified that met the inclusion criteria, 31 (76%) used an inappropriate statistical test for comparing data derived from case subjects and their matched controls. In response to this finding, we developed an algorithm to support decision-making regarding statistical tests for matched case–control studies.

Extreme temperatures and emergency department admissions for childhood asthma in Brisbane, Australia

Objectives To examine the effect of extreme temperatures on emergency department admissions (EDAs) for childhood asthma. Methods An ecological design was used in this study. A Poisson linear regression model combined with a distributed lag non-linear model was used to quantify the effect of temperature on EDAs for asthma among children aged 0–14 years in Brisbane, Australia, during January 2003–December 2009, while controlling for air pollution, relative humidity, day of the week, season and long-term trends. The model residuals were checked to identify whether there was an added effect due to heat waves or cold spells. Results There were 13 324 EDAs for childhood asthma during the study period. Both hot and cold temperatures were associated with increases in EDAs for childhood asthma, and their effects both appeared to be acute. An added effect of heat waves on EDAs for childhood asthma was observed, but no added effect of cold spells was found. Male children and children aged 0–4 years were most vulnerable to heat effects, while children aged 10–14 years were most vulnerable to cold effects. Conclusions Both hot and cold temperatures seemed to affect EDAs for childhood asthma. As climate change continues, children aged 0–4 years are at particular risk for asthma.

Complications of perioperative warfarin therapy in total knee arthroplasty

Patients presenting for knee replacement on warfarin for medical reasons often require higher levels of anticoagulation peri-operatively than primary thromboprophylaxis and may require bridging therapy with heparin. We performed a retrospective case control study on 149 consecutive primary knee arthroplasty patients to investigate whether anti-coagulation affected short-term outcomes. Specific outcome measures indicated significant increases in prolonged wound drainage (26.8% of cases vs 7.3% of controls, p<0.001); superficial infection (16.8% vs 3.3%, p<0.001); deep infection (6.0% vs 0%, p<0.001); return-to-theatre for washout (4.7% vs 0.7%, p=0.004); and revision (4.7% vs 0.3%, p=0.001). Management of patients on long-term warfarin therapy following TKR is particularly challenging, as the surgeon must balance risk of thromboembolism against post-operative complications on an individual patient basis in order to optimise outcomes.

An outbreak of salmonellosis linked to a marine turtle

In September 1998, an outbreak of gastroenteritis occurred in a coastal Aboriginal community in the Northern Territory over a seven day period. An investigation was conducted by the Center for Disease Control, Territory Health Services. Thirty-six cases were detected and 17% (n=6) were hospitalized. Salmonella chester was isolated from eight of nine stool specimens. Sixty-two percent of cases interviewed (n=28) reported consumption of a green turtle (Chelonia mydas) within a median of 24 hours prior to onset of illness. Of the remainder, all but two were contacts of other cases. Salmonella chester was isolated from a section of partially cooked turtle meat. There are no previous published reports of salmonellosis associated with consumption of sea turtles despite them being a popular food source in coastal communities in the Pacific.

The effect of extent of local resection on patterns of disease progression in malignant pleural mesothelioma

Background We sought to determine whether or not there are differences in disease progression after radical or nonradical (debulking) surgical procedures for malignant pleural mesothelioma. Methods Over a 49-month period, 132 patients with malignant pleural mesothelioma underwent surgery. Fifty-three underwent extrapleural pneumonectomy and 79 underwent nonradical procedures. Time to evidence of clinical disease progression was recorded, as was the site(s) of that disease. Results One-hundred nineteen patients were evaluable, of which 59% (22 radical; 48 nonradical) had disease progression. Overall 30-day mortality was 8.5% (7.5% radical; 9% nonradical). The median time to overall disease progression was considerably longer after extrapleural pneumonectomy than debulking surgery (319 days vs 197 days, p = 0.019), as was the time to local disease progression (631 days vs 218 days, p = 0.0018). There was no preponderance of earlier stage disease in the radical surgery group. There was a trend toward prolonged survival in those undergoing radical surgery, but no significant difference between the groups (497 days vs 324 days, p = 0.079). In those who had extrapleural pneumonectomy, time-to-disease progression significantly decreased with N2 disease compared with N0/1 involvement (197 days vs 358 days, p = 0.02). Conclusions Extrapleural pneumonectomy may be preferable to debulking surgery in malignant pleural mesothelioma to delay disease progression and give greater control of local disease. Involvement of N2 nodes is associated with accelerated disease progression and is therefore a contraindication to extrapleural pneumonectomy. © 2004 by The Society of Thoracic Surgeons.

Cataract surgery in eyes with low corneal astigmatism : implantation of the AcrySof IQ Toric SN6AT2 intraocular lens

Purpose The aim of this study is to assess the refractive and visual outcomes following cataract surgery and implantation of the AcrySof IQ Toric SN6AT2 intraolcular lens (IOL) (Alcon Laboratories, Inc) in patients with low corneal astigmatism. Materials and Methods A retrospective, consecutive, single surgeon series of ninety-eight eyes of 88 patients following cataract surgery and implantation of the AcrySof IQ Toric SN6AT2 IOL in eyes with low preoperative corneal astigmatism. Postoperative measurements were obtained at one month post surgery. Main outcome measures were monocular distance visual acuity and residual refractive astigmatism. Results The mean preoperative corneal astigmatic power vector (APV) was 0.38 ± 0.09 D. Following surgery and implantation of the toric IOL, mean postoperative refractive APV was 0.13 ± 0.10 D. Mean postoperative distance uncorrected visual acuity (UCVA) was 0.08 ± 0.09 logMAR. Postoperative spherical equivalent refraction (SER) resulted in a mean of - 0.23 ± 0.22 D, with 96% of eyes falling within 0.50 D of the target SER. Conclusions The AcrySof IQ Toric SN6AT2 IOL is a safe and effective option for eyes undergoing cataract surgery with low amounts of preoperative corneal astigmatism.

‘Doing’ social justice in early childhood : the potential of leadership

Early childhood education has long been connected with objectives related to social justice. Australian Early Childhood Education and Care (ECEC) has its roots in philanthropic and educational reform movements prevalent at the turn of the 20th century. More recently, with the introduction of the National Early Childhood Reform Agenda, early childhood education has once more been linked to the achievement of aims associated with redressing inequality and disadvantage. According to Jean-Marie, Normore and Brooks (2009), educational leaders have a moral and social obligation to foster equitable practices through advocating for traditionally marginalised and poorly served students while creating a new social order “...that subverts the long standing system that has privileged certain students while oppressing or neglecting others” (p.4). Drawing on extant literature, including data from two previously reported Australian studies in which leadership emerged as having a transformational impact on service delivery, this paper examines the potential of early childhood leadership to generate ‘socially just’ educational communities. With reference to critical theory, we argue that critically informed, intentional and strategic organisational leadership can play a pivotal role in creating changed circumstances and opportunities for children and families. Such leadership includes positional and distributed elements, articulation of values and beliefs, and collective action that is mindful and informed.

Silk purse, sow’s ear : transforming second-Hand clothing into luxury fashion through craft practice

There is more apparel being created than ever before in history. The unsustainable production of materials and the clothing and textile waste that contributes annually to landfill, an estimated 500 000 tonnes of clothing per year in the UK (Gray, 2012) are significant issues inspiring the practice of Australian fashion designers, Carla van Lunn and Carla Binotto. While the contemporary fashion industry is built upon a production and consumption model that is younger than the industrial revolution, the traditions of costume, craft, and bodily adornment are ancient practices. Binotto and van Lunn believe that the potential for sustainable fashion practice lies outside the current industrial manufacturing model. This case study will discuss their fashion label, Maison Briz Vegas, and examine how recycling and traditional craft practices can be used to address the problem of clothing waste and offer an alternative idea of value in fashion and materials, addressing the indicative conference theme, Craft as Sustainability Activism in Practice. “Maison Briz Vegas”, a play on the notion of French luxury and the designers’ new world and sub-tropical home town, Brisbane, is an experimental and craft-based fashion label that uses second-hand cotton T-shirts and wool sweaters as primary materials to create designer fashion. The first collection, titled “The Wasteland”, was conceived and created in Paris in 2011, where designer Carla van Lunn had been living and working for several years. The collection was inspired by the precariousness of the global economy and concerns about climate change. The mountains of discarded clothing found at flea markets provided a textile resource from which van Lunn created a recycled hand-crafted fashion collection with an activist message and was shown to buyers and press during Paris Fashion Week. The label has since become a collaboration with fellow Australian designer Carla Binotto. The craft processes employed in Maison Briz Vegas’ up-cycled fashion collections include original hand block-printing, hand embroidery, quilting and patchwork. Taking an artisanal and slow approach, the designers work to create a hand touched imperfect style in a fashion market flooded with digital printing and fast mass-produced garments. The recycling extends to garment fastenings and embellishments, with discarded jar lids and bottle tops being used as buttons and within embroidery. This process transforms the material and aesthetic value of cheap and generic second-hand clothing and household waste. Maison Briz Vegas demonstrates the potential for craft and design to be an interface for environmental activism within the world of fashion. Presenting garments that are both high-design and thoughtfully recycled in a significant fashion context, such as Paris Fashion Week, Maison Briz Vegas has been able to engage a high-profile luxury fashion audience which has not traditionally considered sustainable or eco practices as relevant or desirable in themselves. The designers are studying how to apply their production model on a greater scale in order to fill commercial orders and reach a wider audience whilst maintaining the element of bespoke, limited edition, and slow hand-craft within their work.

Do sex and atopy influence cough outcome measurements in children?

Background Despite the commonality of cough and its burden, there are no published data on the relationship between atopy or sex on objectively measured cough frequency or subjective cough scores in children. In 202 children with and without cough, we determined the effect of sex and atopy on validated cough outcome measurements (cough receptor sensitivity [CRS], objective cough counts, and cough scores). We hypothesized that in contrast to adult data, sex does not influence cough outcome measures, and atopy is not a determinant of these cough measurements. Methods We combined data from four previous studies. Atopy (skin prick test), the concentration of capsaicin causing two and five or more coughs (C2 and C5, respectively), objectively measured cough frequency, and cough scores were determined and their relationship explored. The children’s (93 girls, 109 boys) mean age was 10.6 years (SD 2.9), and 56% had atopy. Results In multivariate analysis, CRS was influenced by age (C2 coefficient, 5.9; P = .034; C5 coefficient, 29.1; P = .0001). Atopy and sex did not significantly influence any of the cough outcomes (cough counts, C2, C5, cough score) in control subjects and children with cough. Conclusions Atopy does not influence important cough outcome measures in children with and without chronic cough. However, age, but not sex, influences CRS in children. Unlike adult data, sex does not affect objective counts or cough score in children with and without chronic cough. Studies on cough in children should be age matched, but matching for atopic status and sex is less important.

Adolescent pedometer protocols : examining reactivity, tampering and participants' perceptions

The aim of this study was to investigate adolescents' potential reactivity and tampering while wearing pedometers by comparing different monitoring protocols to accelerometer output. The sample included adolescents (N=123, age range=14-15 years) from three secondary schools in New South Wales, Australia. Schools were randomised to one of the three pedometer monitoring protocols: (i) daily sealed (DS) pedometer group, (ii) unsealed (US) pedometer group or (iii) weekly sealed (WS) pedometer group. Participants wore pedometers (Yamax Digi-Walker CW700, Yamax Corporation, Kumamoto City, Japan) and accelerometers (Actigraph GT3X+, Pensacola, USA) simultaneously for seven days. Repeated measures analysis of variance was used to examine potential reactivity. Bivariate correlations between step counts and accelerometer output were calculated to explore potential tampering. The correlation between accelerometer output and pedometer steps/day was strongest among participants in the WS group (r=0.82, P <= 0.001), compared to the US (r=0.63, P <= 0.001) and DS (r=0.16, P=0.324) groups. The DS (P <= 0.001) and US (P=0.003), but not the WS (P=0.891), groups showed evidence of reactivity. The results suggest that reactivity and tampering does occur in adolescents and contrary to existing research, pedometer monitoring protocols may influence participant behaviour.

Applying academagogy : the transference of an organised heuristic teaching approach to the digital realm

Much has been written about transferring class materials and teaching techniques to digital platforms, but less has been written about applying heuristic organizing constructs in the same manner. With the transformation of learning ecologies over the past decades as well as requirements to adjust to constantly shifting digital tools and environments, the challenges for learning facilitators are to readily adapt and change, as well as to engage a changing learner demographic. However, most importantly is to engage most effectively with learners in these online environments. This article reviews the existing literature in the heuristic construct of academagogy [1] and applies a case study methodology to discussion of the first application of academagogy to the online delivery of an undergraduate design unit. Through a focus on effective teaching and learning techniques, the transfer from face-to-face (f2f) to the digital realm is explored through four main focal points: Tools for teaching, teaching and learning, communicating with students, and effective teaching methods. These four focal points are then used to discuss ways to meet the challenges of teaching online including how they create new dimensions in teaching practice and how the digital experience changes learning experiences. The article concludes with reflection and consolidation of the similarities and differences between the face-to-face and digital deliveries, and by suggesting changes to the academagogic heuristic to enable its use more easily in a digital space.

Impact of nitrification inhibitor (DMPP) on soil nitrous oxide emissions from an intensive broccoli production system in sub-tropical Australia

Vegetable cropping systems are often characterised by high inputs of nitrogen fertiliser. Elevated emissions of nitrous oxide (N2O) can be expected as a consequence. In order to mitigate N2O emissions from fertilised agricultural fields, the use of nitrification inhibitors, in combination with ammonium based fertilisers, has been promoted. However, no data is currently available on the use of nitrification inhibitors in sub-tropical vegetable systems. A field experiment was conducted to investigate the effect of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on N2O emissions and yield from broccoli production in sub-tropical Australia. Soil N2O fluxes were monitored continuously (3 h sampling frequency) with fully automated, pneumatically operated measuring chambers linked to a sampling control system and a gas chromatograph. Cumulative N2O emissions over the 5 month observation period amounted to 298 g-N/ha, 324 g-N/ha, 411 g-N/ha and 463 g-N/ha in the conventional fertiliser (CONV), the DMPP treatment (DMPP), the DMMP treatment with a 10% reduced fertiliser rate (DMPP-red) and the zero fertiliser (0N), respectively. The temporal variation of N2O fluxes showed only low emissions over the broccoli cropping phase, but significantly elevated emissions were observed in all treatments following broccoli residues being incorporated into the soil. Overall 70–90% of the total emissions occurred in this 5 weeks fallow phase. There was a significant inhibition effect of DMPP on N2O emissions and soil mineral N content over the broccoli cropping phase where the application of DMPP reduced N2O emissions by 75% compared to the standard practice. However, there was no statistical difference between the treatments during the fallow phase or when the whole season was considered. This study shows that DMPP has the potential to reduce N2O emissions from intensive vegetable systems, but also highlights the importance of post-harvest emissions from incorporated vegetable residues. N2O mitigation strategies in vegetable systems need to target these post-harvest emissions and a better evaluation of the effect of nitrification inhibitors over the fallow phase is needed.

The effect of trade openness on deforestation: empirical analysis for 142 countries

This study explores the effect of trade openness on deforestation. Previous studies do not find a clear effect of trade openness on deforestation. We use updated data on the annual rate of deforestation for 142 countries from 1990 to 2003, treat trade and income as endogenous, and take into consideration an adjustment process by applying a dynamic model. We find that an increase in trade openness increases deforestation for non-OECD countries while slowing down deforestation for OECD countries. There is a possibility that both capital-labor and environmental-regulation effects have a negative impact on deforestation in developing countries, whereas the opposite holds in developed countries. © 2012 Springer Japan.

In-hospital mortality rates after a cemented femoral component for displaced neck of femur fractures

Aim This prospective cohort study investigated whether the use of preoperative anticoagulants is an independent risk factor for the outcomes of surgical treatment of patients with a neck of femur fracture. Methods Data was obtained from a prospectively collected database. All patients admitted for a neck of femur fracture between Nov 2010 and Oct 2011 were included. This resulted in three hundred twenty-eight patients with 330 neck of femur fractures. Four groups were defined; patients preoperatively (i) on aspirin (n = 105); (ii) on clopidogrel (n = 28); (iii) on warfarin (n = 30), and; (iv) without any anticoagulation history (n = 167, the control group). The non-warfarin group included the aspirin group, clopidogrel group and the control group. Primary outcome was the in-hospital mortality. Secondary outcomes were the postoperative complications, return to theatre and length of stay. Results Thirteen in-hospital deaths were identified, 4 deaths in the aspirin group, 1 death in the clopidogrel group, 2 deaths in the warfarin group and 6 deaths in the control group. No significant difference in the mortality rates was found between the different groups. Also in the secondary outcomes, no significant difference was found between the four groups. A trend to a higher wound complication rate for the warfarin group was detected. Conclusion The use of clopidrogel or aspirin pre operatively is not an influence on short term patient outcome for patients with a neck of femur fracture. Surgical procedures should not be delayed to reverse their influence.