Does Morningstar Shine in the Universe of Mutual Funds? A Study on Morningstar Mutual Fund Ratings

Using data from Morningstar Principia CDs and employing standard methodologies, we examine the extent to which two mutual fund ratings: Morningstar star ratings and Morningstar stewardship grades can predict future fund performance. In particular, we investigate whether the combined predictive power of the two ratings exceeds that of a single rating. We decompose funds into various groups characterized by fund age and fund categories in order to address such issues as whether predictive performance is uniform across characteristic-based groups. Although our analysis shows that none of the ratings alone possesses strong predictive power, there is statistical evidence to support the notion that combined rating is superior to single rating in forecasting future returns. However, the evidence is not overwhelming enough to justify the efficacy of an investment strategy based primarily on Morningstar ratings. Besides studying predictability of ratings, we also construct a logistic regression model to seek potential determinants of the stewardship grades. We find that funds with good stewardship grades are generally those that incur low expenses, possess a large asset base and are managed by experienced fund managers. Finally, we investigate whether the two Morningstar ratings exhibit short-term persistence. Our findings indicate that the degree of persistence (as measured by the percentage of funds that retain their initial rating over a 12-month period) of the stewardship grades is much more pronounced than that of the star ratings

Controlling the state of a reverberation chamber by means of a random multiple-antenna stirring

International audienceIn this paper we introduce a novel technique based on the random excitation of several antennas. As opposed to previous attempts at this approach, the random signals are correlated by means of a pre-conditioning filter, in order to increase the number of accessible degrees of freedom and optimize the covariance matrix of the field measured in the chamber. A dramatic improvement is observed at those frequencies where standard mechanical stirrers fail

Theft prevention using wireless security system (WSS)

This paper presents a developed RFID based theft prevention system such that luxurious belongings, such as laptops which are monitored from being stolen. Global systems mobile (GSM) module is added to provide a complementary system to feedback to the users. The laptop tag ID and its timer sensed from RFID reader are registered in the system server. When the connectivity is broken when the laptop is taken away by more than its allowable distance, an alarm system will be alerted from server. A short message alerting the owner will be sent via the GSM module within a short period of time. This integrated system of RFID and GSM modules form a robust wireless security system. This system can be improved by using Bluetooth pervasive technology such that it can be exploited easily since it is been embedded in most of the mobile devices

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

AbstractObjective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05).Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA

DDX3X loss is an adverse prognostic marker in diffuse large B-cell lymphoma and is associated with chemoresistance in aggressive non-Hodgkin lymphoma subtypes.

Funder: addenbrooke's charitable trust, cambridge university hospital