Allocating harmonic emission to MV customers in long feeder systems

Previous work has attempted to find satisfactory methods for the allocation of harmonic current emission MV subsystems containing long feeders. It has been proposed that best use of the network\u27s harmonic absorption capacity is made if the allocated current varies with the inverse square root of the harmonic impedance at the point of connection. It has been shown that an exact solution following this principle requires an impracticably large amount of data. Here it is assumed that each feeder supplied from a given substation has its load distributed uniformly and continuously along it, giving equations requiring only a modest amount of data. It is demonstrated by means of a suitable example that the method is sufficiently accurate for practical situations where loads are lumped non-uniformly

Perceptions of Australasian emergency department staff of the impact of alcohol-related presentations

Objectives: To survey emergency department (ED) clinical staff about their perceptions of alcohol-related presentations. Design, setting and participants: A mixed methods online survey of ED clinicians in Australia and New Zealand, conducted from 30 May to 7 July 2014. Main outcome measures: The frequency of aggression from alcoholaffected patients or their carers experienced by ED staff; the perceived impact of alcohol-related presentations on ED function, waiting times, other patients and staff. Results: In total, 2002 ED clinical staff completed the survey, including 904 ED nurses (45.2%) and 1016 ED doctors (50.7%). Alcohol-related verbal aggression from patients had been experienced in the past 12 months by 97.9% of respondents, and physical aggression by 92.2%. ED nurses were the group most likely to have felt unsafe because of the behaviour of these patients (92% reported such feelings). Alcohol-related presentations were perceived to negatively or very negatively affect waiting times (noted by 85.5% of respondents), other patients in the waiting room (94.4%), and the care of other patients (88.3%). Alcohol-affected patients were perceived to have a negative or very negative impact on staff workload (94.2%), wellbeing (74.1%) and job satisfaction (80.9%). Conclusions: Verbal and physical aggression by alcohol-affected patients is commonly experienced by ED clinical staff. This has a negative impact on the care of other patients, as well as on staff wellbeing. Managers of health services must ensure a safe environment for staff and patients. More importantly, a comprehensive public health approach to changing the prevailing culture that tolerates alcohol-induced unacceptable behaviour is required

Geolocator studies on Ruddy Turnstones Arenaria interpres and Greater Sandplovers Charadrius leschenaultii in the East Asian-Australasia Flyway reveal widely different migration strategies

In 2010, following successful trials with geolocators on Ruddy Turnstones in 2009, a total of 105 units, of four different models, were deployed at five locations on Ruddy Turnstones and Greater Sandplovers. Geolocator retrieval rates were 44% on Ruddy Turnstone and 27% on Greater Sandplover. Complete (59%) and partial (15%) technical failure rates on geolocators were high and were mostly the result of wear and saltwater corrosion. All 30 units from the Swiss Ornithological Institute failed. Only half of the Mk10 and Mk12 units from the British Antarctic Survey produced full migration histories. The northward migration of Ruddy Turnstones was on a narrow path with many birds completing an initial non-stop flight of 7,600 km to Taiwan. Later, most made a stopover in the Yellow Sea. Median migration duration was 39.5 days and average migration speed of the first major leg of the journey (assuming the birds followed the great circle route between stopovers) was 63.4 kph. Southward migration paths showed a much wider spread, ranging from Mongolia to the central Pacific. The latter involved the same bird that had been tracked along this route the previous year. It has now been logged on similar 27,000 km round trips in two successive years. The median duration of southward migration (78 days) was nearly twice that of northward migration and data on average migration speed for just two migration legs indicated that it might be lower, 30 and 40 kph being the values recorded. Greater Sandplovers were only tracked on northward migration but seemed to follow a similar migration strategy with a large initial non-stop flight followed by shorter flights and more regular stopovers. Plans are outlined for further analyses and future deployments of geolocators

Experience in the application of IEC/TR 61000-3-6 to harmonic allocation in transmission systems

Technical report IEC/TR 61000-3-6 is widely used as a guide to harmonic management in HV and MV networks, assisting in coordination of harmonic levels between utility and customer. In 2001, Australia and New Zealand adopted the harmonic standard AS/NZS 61000.3.6, which closely follows the above IEC technical report. As a result, transmission utilities and connected loads are required by government regulations to abide by the harmonic allocations set by the standard. The technical report contains some useful general principles which can be applied to the harmonic management of power systems. However, unexpected difficulties can be found when attempts are made to apply them to large power systems. The formal procedure recommended by the standard for calculation of harmonic emission levels limits the voltage at the point of connection. There can be situations where the highest harmonic voltages are remote from the PCC. This can be accounted for by taking into account interactions between each injecting load and all other busbars in one single step. This leads to the development of a harmonic allocation constant , which will apply to the entire transmission network, as a measure of the ability of the network to absorb harmonics without violating a set planning limit. At present, the allocation procedure given in the standard implies consideration of only a single network operation scenario. However, substantial variations have been identified in the harmonic behaviour of transmission networks, including harmonic absorption capacity, with changes in generator commitment and switching configuration. The proposed approach accounts for variations by taking data from multiple network scenarios. For the specification of an easily-measurable harmonic current emission level - rather than a harmonic voltage level - for a particular customer, the network harmonic impedance is necessary. This quantity can vary substantially at the one busbar in a transmission network. The application of a standardised hth harmonic impedance is proposed which is based on the fundamental frequency fault level at the PCC. IEC/TR 61000-3-6 gives no guidance as to methods of treating harmonic resonances in transmission systems. Resonances will occur in any transmission system with sufficient line lengths, and will impose substantial constraints on harmonic allocation if computer calculations are accepted without modification. It is unclear if these resonances are of practical importance, and it is proposed that resonance amplifications be limited to allow useful allocations until their importance has been established by field results

Non-compliance with clinical guidelines increases the risk of complications after primary total hip and knee joint replacement surgery

Background Total hip and total knee replacement (THR/TKR) are common and effective surgeries to reduce the pain and disability associated with arthritis but are associated with small but significant risks of preventable complications such as surgical site infection (SSI) and venous-thrombo-embolism (VTE). This study aims to determine the degree to which hospital care was compliant with clinical guidelines for the prevention of SSI and VTE after THR/TKR; and whether non-compliant prophylaxis is associated with increased risk of complications. Methods and findings A prospective multi-centre cohort study was undertaken in consenting adults with osteoarthritis undergoing elective primary TKR/THR at one of 19 high-volume Australian public or private hospitals. Data were collected prior to surgery and for one-year post-surgery. Four adjusted logistic regression analyses were undertaken to explore associations between binary non-compliance and the risk of surgical complications: (1) composite (simultaneous) non-compliance with both (VTE and antibiotic) guidelines and composite complications [all-cause mortality, VTE, readmission/reoperation for joint-related reasons (one-year) and non-joint-related reasons (35-days)], (2) VTE non-compliance and VTE outcomes, (3) antibiotic non-compliance and any SSI, and (4) antibiotic non-compliance and deep SSI. Data were analysed for 1875 participants. Guideline non-compliance rates were high: 65% (VTE), 87% (antibiotics) and 95% (composite guideline). Composite non-compliance was not associated with composite complication (12.8% vs 8.3%, adjusted odds ratio [AOR] = 1.41, 95%CI 0.68–3.45, p = 0.40). Non-compliance with VTE guidelines was associated with VTE outcomes (5% vs 2.4%, AOR = 2.83, 95%CI 1.59–5.28,p < 0.001). Non-compliance with antibiotic guidelines was associated with any SSI (14.8% vs 6.1%, AOR = 1.98, 95%CI 1.17–3.62,p = 0.02) but not deep infection (3.7% vs 1.2%,AOR = 2.39, 95%CI 0.85–10.00, p = 0.15). Conclusions We found high rates of clinical variation and statistically significant associations between non-compliance with VTE and antibiotic guidelines and increased risk of VTE and SSI, respectively. Complications after THR/TKR surgery may be decreased by improving compliance with clinical guidelines

Carriage of an ACME II variant may have contributed to methicillin-resistant staphylococcus aureus sequence type 239-like strain replacement in Liverpool hospital, Sydney, Australia

Approximately 39% of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 239 (ST239)-like bloodstream isolates from Liverpool Hospital (obtained between 1997 and 2008) carry an arginine catabolic mobile element (ACME). Whole-genome sequencing revealed that an ACME II variant is located between orfX and SCCmec III, and based on pulsed-field gel electrophoresis patterns and temporal relationships of all ST239-like isolates (n = 360), ACME carriage may have contributed to subpulsotype strain replacement

Compliance with Australian Orthopaedic Association guidelines does not reduce the risk of venous thromboembolism after total hip and knee arthroplasty

Preventing avoidable venous-thrombo-embolism (VTE) is a priority to improve patient and service outcomes after total hip and total knee arthroplasty (THA, TKA), but compliance with relevant clinical guidelines varies. This study aims to determine the degree to which prophylaxis was compliant with Australian Orthopaedic Association (AOA) VTE prophylaxis guidelines and whether non-compliance is associated with increased risk of VTE. A prospective multi-centre cohort study of adults with osteoarthritis undergoing primary TKA/THA was completed at 19 high-volume public and private hospitals. Data were collected prior to surgery and for one-year post-surgery. Logistic regression was undertaken to explore associations between non-compliance with AOA VTE prophylaxis guidelines and symptomatic 90-day VTE outcomes. Data were analysed for 1838 participants from 19 sites. The rate of non-compliance with all clinical guideline recommendations was 20.1% (N = 369), with 14.1% (N = 259) non-compliance for risk-stratified prophylaxis, 35.8% (N = 658) for duration, and 67.8% (N = 1246) for other general recommendations. Symptomatic VTE was experienced up to 90-days post-surgery by 48 people (2.6%). Overall guideline non-compliance (AOR = 0.93, 95%CI = 0.4 to 1.3, p = 0.86) was not associated with a lower risk of symptomatic 90-day VTE. Results were consistent when people with high bleeding risk were excluded (AOR = 0.94, 95%CI = 0.44 to 2.34, p = 0.89). Non-compliance with the AOA VTE prophylaxis guidelines was not associated with risk of 90-day VTE after arthroplasty. This counterintuitive finding is concerning and necessitates a rigorous review of the AOA VTE prevention clinical guideline

Association between VTE and antibiotic prophylaxis guideline compliance and patient-reported outcomes after total hip and knee arthroplasty : an observational study

Background: Surgical site infection (SSI) and venous thromboembolism (VTE) are associated with high burden and cost and are considered largely preventable following total knee or hip arthroplasty (TKA, THA). The risk of developing VTE and SSI is reduced when prophylaxis is compliant with evidence-based clinical guidelines. However, the association between VTE and antibiotic prophylaxis clinical guideline compliance and patient-reported outcome measures (PROMs) after THA/TKA is unknown. This study aims to explore whether care that is non-compliant with VTE and antibiotic guideline recommendations is associated with PROMs (Oxford Hip/Knee Score and EQ-5D Index scores) at 90- and 365-days after surgery. Methods: This prospective observational study included high-volume arthroplasty public and private sites and consenting eligible participants undergoing elective primary THA/TKA. We conducted multiple linear regression and linear mixed-effects modelling to explore the associations between non-compliance with VTE and antibiotic guidelines, and PROMs. Results: The sample included 1838 participants. Compliance with VTE and antibiotic guidelines was 35% and 13.2% respectively. In adjusted modelling, non-compliance with VTE guidelines was not associated with 90-day Oxford score (β = − 0.54, standard error [SE] = 0.34, p = 0.112) but was significantly associated with lower (worse) 365-day Oxford score (β = − 0.76, SE = 0.29, p = 0.009), lower EQ-5D Index scores at 90- (β = − 0.02 SE = 0.008, p = 0.011) and 365-days (β = − 0.03, SE = 0.008, p = 0.002). The changes in Oxford and EQ-5D Index scores were not clinically important. Noncompliance with antibiotic guidelines was not associated with either PROM at 90- (Oxford: β = − 0.45, standard error [SE] = 0.47, p = 0.341; EQ-5D: β = − 0.001, SE = 0.011, p = 0.891) or 365-days (Oxford score: β = − 0.06, SE = 0.41, p = 0.880 EQ-5D: β = − 0.010, SE = 0.012, p = 0.383). Results were consistent when complications were included in the model and in linear mixed-effects modelling with the insurance sector as a random effect. Conclusions: Non-compliance with VTE prophylaxis guidelines, but not antibiotic guidelines, is associated with statistically significant but not clinically meaningful differences in Oxford scores and EQ-5D Index scores at 365 days

Rapid population decline in migratory shorebirds relying on Yellow Sea tidal mudflats as stopover sites

Migratory animals are threatened by human-induced global change. However, little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. Using 20 years of continent-wide citizen science data, we assess population trends of ten shorebird taxa that refuel on Yellow Sea tidal mudflats, a threatened ecosystem that has shrunk by >65% in recent decades. Seven of the taxa declined at rates of up to 8% per year. Taxa with the greatest reliance on the Yellow Sea as a stopover site showed the greatest declines, whereas those that stop primarily in other regions had slowly declining or stable populations. Decline rate was unaffected by shared evolutionary history among taxa and was not predicted by migration distance, breeding range size, non-breeding location, generation time or body size. These results suggest that changes in stopover habitat can severely limit migratory populations

SARS Coronavirus-2 microneutralisation and commercial serological assays correlated closely for some but not all enzyme immunoassays

Serological testing for SARS-CoV-2-specific antibodies provides important research and diagnostic information relating to COVID-19 prevalence, incidence and host immune response. A greater understanding of the relationship between functionally neutralising antibodies detected using microneutralisation assays and binding antibodies detected using scalable enzyme immunoassays (EIA) is needed in order to address protective immunity post-infection or vaccination, and assess EIA suitability as a surrogate test for screening of convalescent plasma donors. We assessed whether neutralising antibody titres correlated with signal cut-off ratios in five commercially available EIAs, and one in-house assay based on expressed spike protein targets. Sera from recovered patients or convalescent plasma donors who reported laboratory-confirmed SARS-CoV-2 infection (n = 200), and negative control sera collected prior to the COVID-19 pandemic (n = 100), were assessed in parallel. Performance was assessed by calculating EIA sensitivity and specificity with reference to microneutralisation. Neutralising antibodies were detected in 166 (83%) samples. Compared with this, the most sensitive EIAs were the Cobas Elecsys Anti-SARS-CoV-2 (98%) and Vitros Immunodiagnostic Anti-SARS-CoV-2 (100%), which detect total antibody targeting the N and S1 antigens, respectively. The assay with the best quantitative relationship with microneutralisation was the Euroimmun IgG. These results suggest the marker used (total Ab vs. IgG vs. IgA) and the target antigen are important determinants of assay performance. The strong correlation between microneutralisation and some commercially available assays demonstrates their potential for clinical and research use in assessing protection following infection or vaccination, and use as a surrogate test to assess donor suitability for convalescent plasma donation