Intermediate ice scour disturbance is key to maintaining a peak in biodiversity within the shallows of the Western Antarctic Peninsula.

Climate-related disturbance regimes are changing rapidly with profound consequences for ecosystems. Disturbance is often perceived as detrimental to biodiversity; however, the literature is divided on how they influence each other. Disturbance events in nature are diverse, occurring across numerous interacting trophic levels and multiple spatial and temporal scales, leading to divergence between empirical and theoretical studies. The shallow Antarctic seafloor has one of the largest disturbance gradients on earth, due to iceberg scouring. Scour rates are changing rapidly along the Western Antarctic Peninsula because of climate change and with further changes predicted, the Antarctic benthos will likely undergo dramatic shifts in diversity. We investigated benthic macro and megafaunal richness across 10-100 m depth range, much of which, 40-100 m, has rarely been sampled. Macro and megafauna species richness peaked at 50-60 m depth, a depth dominated by a diverse range of sessile suspension feeders, with an intermediate level of iceberg disturbance. Our results show that a broad range of disturbance values are required to detect the predicted peak in biodiversity that is consistent with the Intermediate Disturbance Hypothesis, suggesting ice scour is key to maintaining high biodiversity in Antarctica's shallows.

Realization of Vertically Aligned, Ultrahigh Aspect Ratio InAsSb Nanowires on Graphite.

The monolithic integration of InAs(1-x)Sb(x) semiconductor nanowires on graphitic substrates holds enormous promise for cost-effective, high-performance, and flexible devices in optoelectronics and high-speed electronics. However, the growth of InAs(1-x)Sb(x) nanowires with high aspect ratio essential for device applications is extremely challenging due to Sb-induced suppression of axial growth and enhancement in radial growth. We report the realization of high quality, vertically aligned, nontapered and ultrahigh aspect ratio InAs(1-x)Sb(x) nanowires with Sb composition (xSb(%)) up to ∼12% grown by indium-droplet assisted molecular beam epitaxy on graphite substrate. Low temperature photoluminescence measurements show that the InAs(1-x)Sb(x) nanowires exhibit bright band-to-band related emission with a distinct redshift as a function of Sb composition providing further confirmation of successful Sb incorporation in as-grown nanowires. This study reveals that the graphite substrate is a more favorable platform for InAs(1-x)Sb(x) nanowires that could lead to hybrid heterostructures possessing potential device applications in optoelectronics.

The health status of people claiming compensation for musculoskeletal injuries following road traffic crashes is not altered by an early intervention programme: a comparative study.

OBJECTIVE: To compare health outcomes among claimants compared to those who were ineligible or choose not to lodge a compensation claim. We also evaluated the effect of an early intervention programme on the health outcomes of the participants. DESIGN: Prospective comparative study using sequential cohorts. SUBJECTS: People presenting to hospital emergency departments with mild to moderate musculoskeletal injuries following road traffic crashes. INTERVENTION: referral to an early intervention programme for assessment by musculoskeletal physician, pain management education, promotion of self-management and encouragement of early activity. MAIN OUTCOMES: The 36-Item Short-Form Survey (SF-36); Hospital Anxiety and Depression Scale (HADS) and Functional Rating Index (FRI) scores were assessed at post-crash and at 12 months. RESULTS: At 12 months, mean scores in six and five of the SF-36 domains were significantly lower among participants who claimed compensation versus those who chose not to claim or were ineligible, respectively. Differences in mean SF-36 scores ranged from 3.0 ('general health perception') to 8.0 units ('role limitations due to physical problems'). Participants who claimed compensation had 6.3- and 4.6-units lower SF-36 physical component score compared to those who were ineligible (p=0.001) or chose not to claim (p=0.01), respectively. Participants who claimed compensation reported a worse HADS-depression score of 6.46 versus 4.97 and 4.69 observed in those who were ineligible (p=0.04) or did not claim (p=0.01). Claimants had worse FRI scores compared to non-claimants (p=0.01) and those who were ineligible (p=0.01). The early intervention did not improve health outcomes, 12 months after injury. CONCLUSIONS: Claiming compensation was associated with a worse health status for people with soft tissue injuries caused by road traffic crashes. The health status in people claiming compensation was not altered by an early intervention programme.

Charged nano-domes and bubbles in epitaxial graphene.

For the first time, new epitaxial graphene nano-structures resembling charged 'bubbles' and 'domes' are reported. A strong influence, arising from the change in morphology, on the graphene layer's electronic, mechanical and optical properties has been shown. The morphological properties of these structures have been studied with atomic force microscopy (AFM), ultrasonic force microscopy (UFM) and Raman spectroscopy. After initial optical microscopy observation of the graphene, a detailed description of the surface morphology, via AFM and nanomechanical UFM measurements, was obtained. Here, graphene nano-structures, domes and bubbles, ranging from a few tens of nanometres (150­200 nm) to a few µm in size have been identified. The AFM topographical and UFM stiffness data implied the freestanding nature of the graphene layer within the domes and bubbles, with heights on the order of 5­12 nm. Raman spectroscopy mappings of G and 2D bands and their ratio confirm not only the graphene composition of these structures but also the existence of step bunching, defect variations and the carrier density distribution. In particular, inside the bubbles and substrate there arises complex charge redistribution; in fact, the graphene bubble­substrate interface forms a charged capacitance. We have determined the strength of the electric field inside the bubble­substrate interface, which may lead to a minigap of the order of 5 meV opening for epitaxial graphene grown on 4H-SiC face-terminated carbon.

An early intervention programme had no detectable influence on the health status of people with musculoskeletal injuries following road traffic crashes: comparative study.

OBJECTIVE: To compare the health status of people with minor injuries from road traffic crashes that are exposed to an early, active intervention programme (intervention group) with those receiving usual care (control group) over a 12 month period. DESIGN: Prospective comparative study using sequential cohorts. SUBJECTS: People presenting to hospital emergency departments with mild to moderate musculoskeletal injuries following road traffic crashes. MAIN OUTCOME MEASURES: Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure; Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI) recorded immediately post-crash, at 6 months and at 12 months after injury. RESULTS: There were 95 participants allocated to the control group and 98 allocated to the intervention group. Participants were enrolled at a mean of 9.3 days following the crash. There were no significant differences in baseline health measures between the groups. Apart from a small improvement in anxiety for the intervention group, there were no significant differences in health status between the groups. Twenty percent of participants in the intervention group received treatment from external healthcare providers that was inconsistent with the recommendations of the intervention programme. CONCLUSIONS: The intervention programme failed to result in a clinically significant improvement in health outcomes compared with usual care. There is some evidence to suggest that the intervention had some psychological benefits, as evidenced by the small improvement in anxiety levels. Limited adherence, frequent use of co-interventions, or other factors (such as intervention content or intensity) may have reduced its effect.

Optical investigation of the natural electron doping in thin MoS2 films deposited on dielectric substrates.

Two-dimensional (2D) compounds provide unique building blocks for novel layered devices and hybrid photonic structures. However, large surface-to-volume ratio in thin films enhances the significance of surface interactions and charging effects requiring new understanding. Here we use micro-photoluminescence (PL) and ultrasonic force microscopy to explore the influence of the dielectric environment on optical properties of a few monolayer MoS2 films. PL spectra for MoS2 films deposited on SiO2 substrates are found to vary widely. This film-to-film variation is suppressed by additional capping of MoS2 with SiO2 and Si(x)N(y), improving mechanical coupling of MoS2 with surrounding dielectrics. We show that the observed PL non-uniformities are related to strong variation in the local electron charging of MoS2 films. In completely encapsulated films, negative charging is enhanced leading to uniform optical properties. Observed great sensitivity of optical characteristics of 2D films to surface interactions has important implications for optoelectronics applications of layered materials.

Fifteen-hour day shifts have little effect on the performance of taskwork by anaesthesia trainees during uncomplicated clinical simulation.

Shiftwork and work-hour limits for junior doctors are now well established in hospital work patterns. In order to ensure that trainees have adequate exposure to daytime elective surgical procedures, there is a tendency to have long shifts that include an after-hours component. However, long shifts can cause performance decrement due to time-on-task fatigue. In addition, shifts that encroach upon sleep time result in sleep loss. Using a high-fidelity patient simulation environment, we undertook a randomised, controlled trial to examine fatigue effects. A within-subjects comparison was used to evaluate the effect of 15-hour day shifts on the performance of 12 anaesthesia registrars. Preoperative assessment, machine check and taskwork using 42 task categories were evaluated. In both conditions, there was failure to meet current guidelines for preoperative evaluation or machine check, and when fatigued there was a 'trend' (P=0.06) to a reduction in the number of items in the machine check. With increase in time awake, there was an increase in time taken for explanation to the patient, an increase in mean duration of explanation to the patient, more time looking at the intravenous line or fluids when multi-tasking but less time adjusting the intravenous fluid. These effects are minor during routine uncomplicated induction of anaesthesia, but further investigation is needed to examine fatigue effects during non-routine circumstances.

The influence of fault on health in the immediate post-crash period following road traffic crashes.

OBJECTIVE: To compare the early health status of people who sustained injuries during road traffic crashes (RTC) in which they were at fault (AF), with people who sustained injuries in RTC in which they were not at fault (NAF). DESIGN: Prospective cohort study. SUBJECTS: People presenting to the emergency department with mild to moderate musculoskeletal injuries following RTC. MAIN OUTCOME MEASURES: Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure; Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI) recorded immediately post-crash. RESULTS: 193 people participated in the study and were enrolled a mean of 9.3 days following the crash. The mean age was 37 years and 60% were female. 71% were NAF. There was a significantly higher number of females in the NAF group (65% compared with 35% males; p<0.001). Neck and back injuries were reported by 90.4% of the NAF group compared to 69.1% of the AF group (p<0.001). There were no significant differences in PCS, FRI or pain intensity between the two groups at a mean of 9.3 days after the crash. The mean MCS for the NAF group was significantly worse than for the AF group (31.4 compared to 37.3; p = 0.005). The SF-36 domain revealed a significantly worse adjusted mean role emotional score for the NAF group (23.4 compared to 32.5, p = 0.002). Females had significantly worse MCS score than males (30.6 and 38.1 respectively; p<0.001) and worse adjusted mean anxiety and depression scores (10 compared to 7.8; p = 0.002 and 7.6 compared to 5.5; p = 0.002 respectively). CONCLUSIONS: Despite there being no difference in physical health status, the NAF group demonstrated more emotional and mental disturbance than the AF group; and this was significantly worse for females. Treatment strategies should focus on addressing early pain and disability as well as providing appropriate psychological interventions, particularly for people not at fault following RTC.

The association of compensation on longer term health status for people with musculoskeletal injuries following road traffic crashes: emergency department inception cohort study.

OBJECTIVE: To compare the health status of people claiming compensation for injuries sustained in road traffic crashes (RTC), with people who do not claim compensation. DESIGN: Prospective cohort study. SETTING: Australian Capital Territory, Australia and a fault based common law compensation scheme. SUBJECTS: People presenting to the emergency department with mild to moderate musculoskeletal injury following RTC. MAIN OUTCOME MEASURES: Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure, Hospital Anxiety and Depression Scale (HADS) and the Functional Rating Index (FRI). These measures are recorded immediately post crash, at 6 and 12 months post crash. RESULTS: 95 people participated in the study and were enrolled a mean of 8.6 (median 8) days following the crash. 86% were followed up to 12 months after injury. Mean age was 37 years, 61% were female and 91% were employed at the time of their injury.33%ultimately claimed compensation, and 25% engaged a lawyer. There were no major differences in baseline personal characteristics or injury related factors between the groups. As expected, involvement as a passenger and in multiple vehicle crashes, were more frequent in the group claiming compensation. Over the duration of the study claiming compensation was associated with lower SF-36 PCS (5.5 (95%CI 8.6 to 2.4), p = 0.001), greater HADS-Anxiety (1.7 (95%CI 0.2­3.3), p = 0.048), and worse FRI (11.2 (95%CI 3.9­18.5), p = 0.003). There was a highly significant improvement in health status between baseline and 6 months after injury, but no further significant change between 6 and 12 months after injury. There was no difference in rate of improvement between the groups. Claiming compensation and psychological factors were independent predictors of worse health status at 12 months. CONCLUSION: In this study the group claiming compensation had overall worse health status following mild to moderate musculoskeletal injuries over the course of the study. There was no difference in rate of improvement between the groups. However, it is not possible to determine whether this negative effect was due to claiming compensation itself or the presence of other unmeasured factors.

The impact of trained assistance on error rates in anaesthesia: a simulation-based randomised controlled trial.

Trained assistance for the anaesthetist appears likely to improve safety in anaesthesia. However, there are few objective data to support this assumption, and the requirement for a trained assistant is not universally enforced. We applied a simulation-based model developed in previous work to test the hypothesis that the presence of a trained assistant reduces error in anaesthesia. Ten randomly selected anaesthetists, five trained anaesthetic technicians and five theatre nurses without training in anaesthesia participated in two simulated emergencies, with anaesthetists working alternately with a technician or a nurse. The mean (SD) error rate per scenario was 4.75 (2.9). There were significantly fewer errors in the technician group than the nurse group (33 vs 62, p = 0.01) and this difference remained significant when errors were weighted for severity. This provides objective evidence supporting the requirement for trained assistance to the anaesthetist, and furthermore, demonstrates that a simulation-based model can provide rigorous evidence on safety interventions in anaesthesia.

A simulation design for research evaluating safety innovations in anaesthesia*.

SUMMARY: It is notoriously difficult to obtain evidence from clinical randomised controlled trials for safety innovations in healthcare. We have developed a research design using simulation for the evaluation of safety initiatives in anaesthesia. We used a standard and a modified scenario in a human-patient simulator, involving a potentially life-threatening problem requiring prompt attention--either a cardiac arrest or a failure in oxygen supply. The modified scenarios involved distractions such as loud music, a demanding and uncooperative surgeon, telephone calls and frequent questions from a medical student. Twenty anaesthetics were administered by 10 anaesthetists. A mean (SD) of 11.3 (2.8) errors per anaesthetic were identified in the oxygen failure scenarios, compared with 8.0 (3.4) in the cardiac arrest scenarios (ANOVA: p = 0.04). The difference between the combined standard scenarios and the combined modified scenarios was not significant. The mean rate of errors overall was 9.7 per simulation, with a pooled SD of 4.46, so in future studies 21 subjects would provide 80% statistical power to show a reduction in error rate of 30% from baseline with p

Psychometric characteristics of simulation-based assessment in anaesthesia and accuracy of self-assessed scores.

The purpose of this study was to define the psychometric properties of a simulation-based assessment of anaesthetists. Twenty-one anaesthetic trainees took part in three highly standardised simulations of anaesthetic emergencies. Scenarios were videotaped and rated independently by four judges. Trainees also assessed their own performance in the simulations. Results were analysed using generalisability theory to determine the influence of subject, case and judge on the variance in judges' scores and to determine the number of cases and judges required to produce a reliable result. Self-assessed scores were compared to the mean score of the judges. The results suggest that 12-15 cases are required to rank trainees reliably on their ability to manage simulated crises. Greater reliability is gained by increasing the number of cases than by increasing the number of judges. There was modest but significant correlation between self-assessed scores and external assessors' scores (rho = 0.321; p = 0.01). At the lower levels of performance, trainees consistently overrated their performance compared to those performing at higher levels (p = 0.0001).

Dislocation of the bearing of the Oxford lateral unicompartmental arthroplasty. A radiological assessment.

When the Oxford unicompartmental meniscal bearing arthroplasty is used in the lateral compartment of the knee, 10% of the bearings dislocate. A radiological review was carried out to establish if dislocation was related to surgical technique. The postoperative radiographs of 46 lateral unicompartmental arthroplasties were analysed. Five variables which related to the position and alignment of the components were measured. Dislocations occurred in six knees. Only one of the five variables, the proximal tibial varus angle, had a statistically significant relationship to dislocation. This variable quantifies the height of the lateral joint line. The mean proximal tibial varus angle for knees the bearings of which had dislocated was 9 degrees and for those which had not it was 5 degrees. In both groups it was greater than would be expected in the normal knee (3 degrees). Our study suggests that a high proximal tibial varus angle is associated with dislocation. The surgical technique should be modified to account for this, with care being taken to avoid damage to or overdistraction of the lateral soft tissues.

A kinematic study of lateral unicompartmental arthroplasty.

When the Oxford unicompartmental meniscal bearing arthroplasty (UCA) is used in the lateral compartment 10% of the bearings dislocate. A fluoroscopic study was performed to investigate if abnormal mid-sagittal plane kinematics was related to bearing dislocation. Video fluoroscopy is an accepted means of determining in-vivo knee kinematics in the sagittal plane. Video fluoroscopy was obtained of 5 Oxford lateral UCAs 10 years post-operatively and of five normal knees. Patellar tendon angle (PTA), derived from dynamic fluoroscopic images, was used to describe the joint kinematics. This in-vivo experiment demonstrated that the PTA/knee relationship for the Oxford lateral UCA is similar to the normal knee. Both the normal knee (r(2)=0.99) and the Oxford lateral UCA (r(2)=0.98) demonstrated a linear relationship between flexion angle and PTA. No significant difference in PTA was found between the normal knee and the Oxford lateral UCA. This study demonstrated normal kinematics, as indicated by PTA, ten years after implantation of the Oxford lateral UCA. It is therefore reasonable to suggest that abnormal kinematics is not a significant factor relating to meniscal bearing dislocation in the lateral compartment.

Defining the femoral axis on lateral knee fluoroscopy.

The methodological detail about determining the femoral axis on lateral fluoroscopic images of the knee is lacking. This paper reports on the use of the posterior border of the lower femoral diaphysis to represent the axis. This method is accurate, simple, reliable and can be used by researchers studying knee joint kinematics using dynamic video fluoroscopy. It is also useful in the outpatient clinic to assess the flexion/extension position of femoral components after knee arthroplasty.

Clinical risk factors for venous thrombosis associated with air travel.

BACKGROUND: Recent reports have linked air travel with venous thrombo-embolism (VTE). Risk factors and associated features of this link are poorly understood. We have accumulated clinical data from a relatively large cohort of patients with traveler's thrombosis. METHODS: A total of 86 patients who developed venous thromboembolism within 28 d of flying were questioned concerning traveling habits, medical history (including risk factors for VTE) and characteristics of the index flight. RESULTS: Of the patients, 72% had at least one risk factor for VTE (excluding thrombophilia) prior to their flight. Of interest, 87% of VTE cases occurred following either a return trip or after an outward journey involving long trips made up of sequential flights. In only two cases could no identifiable risk factor or earlier journey be found. Duration of flights ranged from 2 to 30 h. Of responders, 38% presented with chest symptoms; 92% with VTE developed symptoms within 96 h of their flight. CONCLUSION: We conclude that the majority of VTE associated with air travel occur in those with identifiable risk factors prior to their flight, and that sequential flights may increase this risk.

Achilles tendon rupture associated with ankle fracture.

The case of a 40-year-old man who sustained a medial malleolar fracture with extension of the fracture into the tibial plafond is discussed. Before surgery, the physical examination revealed an Achilles tendon rupture. Surgical treatment to repair the bone and tendon injury was performed. Achilles tendon rupture is not an uncommon injury, but it is rarely associated with a fracture. When a fracture is present, the Achilles tendon injury can be overlooked, which may result in a delay of treatment or residual morbidity.