IDIOSYNCRATIC RISK AND AUSTRALIAN EQUITY RETURNS

In this paper we investigate the relationship between portfolio returns and idiosyncratic risk for Australian stocks. We report that the portfolio with highest idiosyncratic volatility generates an average annual return of over 45%. We observe additionally that the outcome is consistent with an exponential growth process for stock prices. Further, consistent with Malkiel and Xu, we observe that a stock’s idiosyncratic volatility is inversely correlated with the size of the underlying firm. Thus, our model advances an interpretation of the Fama and French finding that portfolios of stocks of small firms offer superior risk-adjusted returns. Moreover, our findings challenge the portfolio theory of Markowitz (1959) and the asset-pricing model of Sharpe (1964).Idiosyncratic risk, Capital Asset Pricing Model, Size effect

There’s always the river: social and environmental equity in rapidly urbanising landscapes in India

In the pursuit of sustainable and liveable cities, Indian built environment practitioners and policymakers are understandably focused on aspects of infrastructure, sanitation and health, given the problems of pollution and environmental degradation are significant urban problems. However, there is little demonstration of understanding of the part that landscape could play in tackling such issues. To explore this, the paper examines two urban rivers in India. It calls on interviews with practitioners, residents and users in Madurai and Ahmedabad, focusing on access and use of the river to explore social and environmental equity. The findings suggest that free, public and safe access to the rivers have reduced over time in both cities, for different reasons. Perceived environmental quality of both rivers has also worsened. We suggest that urban river infrastructure should be reconceptualised to explore the feasibility and acceptability of a more holistic approach to understanding Indian riparian urban landscapes

Validation of Helicopter Gear Condition Indicators Using Seeded Fault Tests

A "seeded fault test" in support of a rotorcraft condition based maintenance program (CBM), is an experiment in which a component is tested with a known fault while health monitoring data is collected. These tests are performed at operating conditions comparable to operating conditions the component would be exposed to while installed on the aircraft. Performance of seeded fault tests is one method used to provide evidence that a Health Usage Monitoring System (HUMS) can replace current maintenance practices required for aircraft airworthiness. Actual in-service experience of the HUMS detecting a component fault is another validation method. This paper will discuss a hybrid validation approach that combines in service-data with seeded fault tests. For this approach, existing in-service HUMS flight data from a naturally occurring component fault will be used to define a component seeded fault test. An example, using spiral bevel gears as the targeted component, will be presented. Since the U.S. Army has begun to develop standards for using seeded fault tests for HUMS validation, the hybrid approach will be mapped to the steps defined within their Aeronautical Design Standard Handbook for CBM. This paper will step through their defined processes, and identify additional steps that may be required when using component test rig fault tests to demonstrate helicopter CI performance. The discussion within this paper will provide the reader with a better appreciation for the challenges faced when defining a seeded fault test for HUMS validation

Non-immune fetal hydrops: etiology and outcome according to gestational age at diagnosis.

OBJECTIVE: Fetal hydrops is associated with increased perinatal morbidity and mortality. The etiology and outcome of fetal hydrops may differ according to the gestational age at diagnosis. The aim of this study was to evaluate the cause, evolution and outcome of non-immune fetal hydrops (NIFH), according to the gestational age at diagnosis. METHODS: This was a retrospective cohort study of all singleton pregnancies complicated by NIFH, at the Fetal Medicine Unit at St George's University Hospital, London, UK, between 2000 and 2018. All fetuses had detailed anomaly and cardiac ultrasound scans, karyotyping and infection screening. Prenatal diagnostic and therapeutic intervention, gestational age at diagnosis and delivery, as well as pregnancy outcome, were recorded. Regression analysis was used to test for potential association between possible risk factors and perinatal mortality. RESULTS: We included 273 fetuses with NIFH. The etiology of the condition varied significantly in the three trimesters. Excluding 30 women who declined invasive testing, the cause of NIFH was defined as unknown in 62 of the remaining 243 cases (25.5%). Chromosomal aneuploidy was the most common cause of NIFH in the first trimester. It continued to be a significant etiologic factor in the second trimester, along with congenital infection. In the third trimester, the most common etiology was cardiovascular abnormality. Among the 152 (55.7%) women continuing the pregnancy, 48 (31.6%) underwent fetal intervention, including the insertion of pleuroamniotic shunts, fetal blood transfusion and thoracentesis. Fetal intervention was associated significantly with lower perinatal mortality (odds ratio (OR), 0.30 (95% CI, 0.14-0.61); P  0.05). CONCLUSIONS: An earlier gestational age at diagnosis of NIFH was associated with an increased risk of aneuploidy and worse pregnancy outcome, including a higher risk of perinatal loss. Fetal therapy was associated significantly with lower perinatal mortality. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology

Validation of the Vaccination Confidence Scale: A Brief Measure to Identify Parents at Risk for Refusing Adolescent Vaccines

Objective To validate a brief measure of vaccination confidence using a large, nationally representative sample of parents. Methods We analyzed weighted data from 9018 parents who completed the 2010 National Immunization Survey–Teen, an annual, population-based telephone survey. Parents reported on the immunization history of a 13- to 17-year-old child in their households for vaccines including tetanus, diphtheria, and acellular pertussis (Tdap), meningococcal, and human papillomavirus vaccines. For each vaccine, separate logistic regression models assessed associations between parents\u27 mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status. We repeated analyses for the scale\u27s 4-item short form. Results One quarter of parents (24%) reported refusal of any vaccine, with refusal of specific vaccines ranging from 21% for human papillomavirus to 2% for Tdap. Using the full 8-item scale, vaccination confidence was negatively associated with measures of vaccine refusal and positively associated with measures of vaccination status. For example, refusal of any vaccine was more common among parents whose scale scores were medium (odds ratio, 2.08; 95% confidence interval, 1.75–2.47) or low (odds ratio, 4.61; 95% confidence interval, 3.51–6.05) versus high. For the 4-item short form, scores were also consistently associated with vaccine refusal and vaccination status. Vaccination confidence was inconsistently associated with vaccine delay. Conclusions The Vaccination Confidence Scale shows promise as a tool for identifying parents at risk for refusing adolescent vaccines. The scale\u27s short form appears to offer comparable performance

Investment Opportunities Forecasting: Extending the Grammar of a GP-based Tool

In this paper we present a new version of a GP financial forecasting tool, called EDDIE 8. The novelty of this version is that it allows the GP to search in the space of indicators, instead of using pre-specified ones. We compare EDDIE 8 with its predecessor, EDDIE 7, and find that new and improved solutions can be found. Analysis also shows that, on average, EDDIE 8's best tree performs better than the one of EDDIE 7. The above allows us to characterize EDDIE 8 as a valuable forecasting tool

Health Monitoring Survey of Bell 412EP Transmissions

Health and usage monitoring systems (HUMS) use vibration-based Condition Indicators (CI) to assess the health of helicopter powertrain components. A fault is detected when a CI exceeds its threshold value. The effectiveness of fault detection can be judged on the basis of assessing the condition of actual components from fleet aircraft. The Bell 412 HUMS-equipped helicopter is chosen for such an evaluation. A sample of 20 aircraft included 12 aircraft with confirmed transmission and gearbox faults (detected by CIs) and eight aircraft with no known faults. The associated CI data is classified into "healthy" and "faulted" populations based on actual condition and these populations are compared against their CI thresholds to quantify the probability of false alarm and the probability of missed detection. Receiver Operator Characteristic analysis is used to optimize thresholds. Based on the results of the analysis, shortcomings in the classification method are identified for slow-moving CI trends. Recommendations for improving classification using time-dependent receiver-operator characteristic methods are put forth. Finally, lessons learned regarding OEM-operator communication are presented

Visit complexity, diagnostic uncertainty, and antibiotic prescribing for acute cough in primary care: a retrospective study

Background: Guidelines and performance measures recommend avoiding antibiotics for acute cough/acute bronchitis and presume visits are straightforward with simple diagnostic decision-making. We evaluated clinician-assigned diagnoses, diagnostic uncertainty, and antibiotic prescribing for acute cough visits in primary care. Methods: We conducted a retrospective analysis of acute cough visits – cough lasting ≤21 days in adults 18–64 years old without chronic lung disease – in a primary care practice from March 2011 through June 2012. Results: Of 56,301 visits, 962 (2%) were for acute cough. Clinicians diagnosed patients with 1, 2, or ≥ 3 cough-related diagnoses in 54%, 35%, and 11% of visits, respectively. The most common principal diagnoses were upper respiratory infection (46%), sinusitis (10%), acute bronchitis (9%), and pneumonia (8%). Clinicians prescribed antibiotics in 22% of all visits: 65% of visits with antibiotic-appropriate diagnoses and 4% of visits with non-antibiotic-appropriate diagnoses. Clinicians expressed diagnostic uncertainty in 16% of all visits: 43% of visits with antibiotic-appropriate diagnoses and 5% of visits with non-antibiotic-appropriate diagnoses. Clinicians expressed uncertainty more often when prescribing antibiotics than when not prescribing antibiotics (30% vs. 12%; p < 0.001). As the number of visit diagnoses increased from 1 to 2 to ≥ 3, clinicians were more likely to express diagnostic uncertainty (5%, 25%, 40%, respectively; p < 0.001) and prescribe antibiotics (16%, 25%, 41%, respectively; p < 0.001). Conclusions: Acute cough may be more complex and have more diagnostic uncertainty than guidelines and performance measures presume. Efforts to reduce antibiotic prescribing for acute cough should address diagnostic complexity and uncertainty that clinicians face

The deep distributions of helium isotopes, radiocarbon, and noble gases along the U.S. GEOTRACES East Pacific Zonal Transect (GP16)

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Marine Chemistry 201 (2018): 167-182, doi:10.1016/j.marchem.2017.03.009.We report the deep distributions of noble gases, helium isotopes, and radiocarbon measured during the U.S. GEOTRACES GP16 East Pacific Zonal Transect between 152 and 77°W at 12- 15°S in the South Pacific. The dominant feature is an intense tongue of hydrothermal effluent that extends more than 4,000 km westward from the East Pacific Rise (EPR) at ~2500m depth. The patterns reveal significant “downstream” variations in water mass structure, advection, and mixing that belie the simple perception of a continuous plume extending westward from the EPR. For example, one feature observed at 120°W, 14°S has tracer signatures that are consistent with a water mass originating from an area as much as 2,000 km south of this section, suggesting a quasi-permanent northward flow on the western flank of the EPR. Helium isotope variations in the plume show a uniquely high 3He/4He source in the tongue compared with typical mid-ocean ridge basalts (MORB), consistent with the anomalously high ratios observed in MORB glasses from the EPR segment just south of this transect. The water column data also reveal that the background 3He/4He east of the EPR is significantly lower than values characteristic of MORB, suggesting an additional, more geographically distributed radiogenic 4He flux of order 107 mol/y into the deep Pacific. In the western end of the section, incoming bottom waters have relatively less hydrothermal hydrothermal helium, more radiocarbon, and more oxygen, as well as negative saturation anomalies for the heavy noble gases (Ar, Kr, and Xe). During the basin-scale upwelling of this water, diapycnal mixing serves to erase these negative anomalies. The relative magnitudes of the increases for the heavy noble gases (Ar, Kr, and Xe) are quantitatively consistent with this process. This leads us to estimate the relatively smaller effects on He and Ne saturations, which range from near zero to 0.2% and 0.3% respectively. With this information, we are able to refine our estimates of the magnitude of 3He and 4He excesses and the absolute 3He/4He ratio of non-atmospheric helium introduced into deep Pacific waters.The work was funded under National Science Foundation grant number OCE-1232991 for WJJ and OCE-1130870 for CRG