1,411 research outputs found
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False Discoveries: Winners and Losers in Mutual Fund Performance
We use a multiple hypothesis testing framework to estimate the false discovery rate (FDR) amongst UK equity mutual funds. For all funds, we find a relatively high FDR for the best funds of 67% (at a 10% significance level), which indicates that only around 2% of all funds truly outperform their benchmarks. For the worst funds the FDR (at a 10% significance level), is relatively small at 15.9% which results in 20% of funds which truly underperform their benchmarks. For different investment styles, this pattern of very few genuine winner funds is repeated for all companies, small companies and equity income funds. However, forming portfolios of funds based on a set of funds for which the FDR is relatively low, produces positive alphas
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A review of behavioural and management effects in mutual fund performance
This paper surveys and critically evaluates the literature on the role of management effects and fund characteristics in mutual fund performance. First, a brief overview of performance measures is provided. Second, empirical findings on the predictive power of fund characteristics in explaining future returns are discussed. Third, the paper reviews the literature on fund manager behavioural biases and the impact these have on risk taking and returns. Finally, the impact of organizational structure, governance and strategy on both fund risk taking and future performance is examined. While a number of surveys on mutual fund performance are available, these have not focused on the role of manager behavioural biases, manager characteristics and fund management strategic behavior on fund performance and risk taking. This review is an attempt to fill this gap. Empirical results indicate that finding successful funds ex-ante is extremely difficult, if not impossible. In contrast, there is strong evidence that poor performance persists for many of the prior "loser fractile" portfolios of funds. A number of manager behavioural biases are prevalent in the mutual fund industry and they generally detract from returns
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The Market Timing Ability of UK Equity Mutual Funds
We apply a recent nonparametric methodology to test the market timing skills of UK equity mutual funds. The methodology has a number of advantages over the widely used regression based tests of Treynor-Mazuy (1966) and Henriksson-Merton (1981). We find a relatively small number of funds (around 1.5%) demonstrate positive market timing ability at a 5% significance level, while around 10-20% of funds exhibit negative (perverse) timing and most funds do not time the market. Our findings indicate that the few skillful market timers possess private market timing signals so their performance cannot be attributed to publicly available information. In terms of fund classifications, there are a small number of successful positive market timers amongst equity income and general equity funds, while a few small company funds time a small company rather than a broad market index. We also apply regression based tests of volatility timing and find evidence that a slightly larger (around 5%) of funds successful time market volatility
Market and Style Timing: German Equity and Bond Funds
We apply parametric and non-parametric estimates to test market and style timing ability of individual German equity and bond mutual funds using a sample of over 500 equity and 350 bond funds, over the period 1990-2009. For equity funds, both approaches indicate no successful market timers in the 1990-1999 or 2000-2009 periods, but in 2000-2009 the non-parametric approach gives fewer unsuccessful market timers than the parametric approach. There is evidence of successful style timing using the parametric approach, and unsuccessful style timing, particularly in the 2000-2009 period. There is evidence of positive and negative bond timing in the 2000-09 period
Atomic oxygen beam source for erosion simulation
A device for the production of low energy (3 to 10 eV) neutral atomic beams for surface modification studies is described that reproduces the flux of atomic oxygen in low Earth orbit. The beam is produced by the acceleration of plasma ions onto a negatively biased plate of high-Z metal; the ions are neutralized and reflected by the surface, retaining some fraction of their incident kinetic energy, forming a beam of atoms. The plasma is generated by a coaxial RF exciter which produces a magnetically-confined (4 kG) plasma column. At the end of the column, ions fall through the sheath to the plate, whose bias relative to the plasma can be varied to adjust the beam energy. The source provides a neutral flux approximately equal to 5 x 10(exp 16)/sq cm at a distance of 9 cm and a fluence approximately equal to 10(exp 20)/sq cm in five hours. The composition and energy of inert gas beams was diagnosed using a mass spectometer/energy analyzer. The energy spectra of the beams demonstrate energies in the range 5 to 15 eV, and qualitatively show expected dependences upon incident and reflecting atom species and potential drop. Samples of carbon film, carbon-based paint, Kapton, mylar, and teflon exposed to atomic O beams show erosion quite similar to that observed in orbit on the space shuttle
Measurement of radiation-pressure-induced optomechanical dynamics in a suspended Fabry-Perot cavity
We report on experimental observation of radiation-pressure induced effects
in a high-power optical cavity. These effects play an important role in next
generation gravitational wave (GW) detectors, as well as in quantum
non-demolition (QND) interferometers. We measure the properties of an optical
spring, created by coupling of an intense laser field to the pendulum mode of a
suspended mirror; and also the parametric instability (PI) that arises from the
nonlinear coupling between acoustic modes of the cavity mirrors and the cavity
optical mode. Specifically, we measure an optical rigidity of N/m, and PI value .Comment: 4 pages, 3 figure
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What Does Rebalancing Really Achieve?
There is now a substantial literature on the effects of rebalancing on portfolio performance. However, this literature contains frequent misattribution between ‘rebalancing returns’ which are specific to the act of rebalancing, and ‘diversification returns’ which can be earned by both rebalanced and unrebalanced strategies. Confusion on this issue can encourage investors to follow strategies which involve insufficient diversification and excessive transactions costs. This paper identifies the misleading claims that are made for rebalanced strategies and demonstrates theoretically and by simulation that the apparent advantages of rebalanced strategies over infinite horizons give an inaccurate impression of their performance over finite horizons
Threat assessment, sense making, and critical decision-making in police, military, ambulance, and fire services
Military and emergency response remain inherently dangerous occupations that require the ability to accurately assess threats and make critical decisions under significant time pressures. The cognitive processes associated with these abilities are complex and have been the subject of several significant, albeit service specific studies. Here, we present an attempt at finding the commonalities in threat assessment, sense making, and critical decision-making for emergency response across police, military, ambulance, and fire services. Relevant research is identified and critically appraised through a systematic literature review of English-language studies published from January 2000 through July 2020 on threat assessment and critical decision-making theory in dynamic emergency service and military environments. A total of 10,084 titles and abstracts were reviewed, with 94 identified as suitable for inclusion in the study. We then present our findings focused on six lines of enquiry: Bibliometrics, Language, Situation Awareness, Critical Decision Making, Actions, and Evaluation. We then thematically analyse these findings to reveal the commonalities between the four services. Despite existing single or dual service studies in the field, this research is significant in that it is the first examine decision making and threat assessment theory across all four contexts of military, police, fire and ambulance services, but it is also the first to assess the state of knowledge and explore the extent that commonality exists and models or practices can be applied across each discipline. The results demonstrate all military and emergency services personnel apply both intuitive and formal decision-making processes, depending on multiple situational and individual factors. Institutional restriction of decision-making to a single process at the expense of the consideration of others, or the inappropriate training and application of otherwise appropriate decision-making processes in certain circumstances is likely to increase the potential for adverse outcomes, or at the very least restrict peak performance being achieved. The applications of the findings of the study not only extend to facilitating improved practice in each of the individual services examined, but provide a basis to assist future research, and contribute to the literature exploring threat assessment and decision making in dynamic contexts
Cardio-protective effects of carnitine in streptozotocin-induced diabetic rats
BACKGROUND: Streptozotocin-induced diabetes (STZ-D) in rats has been associated with carnitine deficiency, bradycardia and left ventricular enlargement. AIM: The purpose of this study was to determine whether oral carnitine supplementation would normalize carnitine levels and cardiac function in STZ-D rats. METHODS: Wistar rats (48) were made hyperglycemic by STZ at 26 weeks of age. Same age normal Wistar rats (24) were used for comparison. Echocardiograms were performed at baseline 2, 6, 10, and 18 weeks after STZ administration in all animals. HbA1c, serum carnitine and free fatty acids (FFA) were measured at the same times. Since STZ-D rats become carnitine deficient, 15 STZ-D rats received supplemental oral carnitine for 16 weeks. RESULTS: The heart rates for the STZ-D rats (290 ± 19 bpm) were less than control rats (324 ± 20 bpm) (p < 0.05). After 4 weeks of oral carnitine supplementation, the serum carnitine and heart rates of the STZ-D rats returned to normal. Dobutamine stress increased the heart rates of all study animals, but the increase in STZ-D rats (141 ± 8 bpm) was greater than controls (79 ± 8 bpm) (p < 0.05). The heart rates of STZ-D rats given oral carnitine, however, were no different than controls (94 ± 9 bpm). The left ventricular mass/body weight ratio (LVM/BW) in the diabetic animals (2.7 ± 0.5) was greater than control animals (2.2 ± 0.3) (p < 0.05) after 18 weeks of diabetes. In contrast, the LVM/BW (2.3 ± .2) of the STZ-D animals receiving supplemental carnitine was the same as the control animals at 18 weeks. CONCLUSION: Thus, supplemental oral carnitine in STZ-D rats normalized serum carnitine, heart rate regulation and left ventricular size. These findings suggest a metabolic mechanism for the cardiac dysfunction noted in this diabetic animal model
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