Mean Group Tests for Stationarity in Heterogenous Panels

This paper proposes the panel-based mean group tests for the null of stationarity against the alternative of unit roots in the presence of both heterogeneity across crosssection units and serial correlation across time periods. Using both sequential and joint asymptotic analyses the proposed test statistic is shown to be distributed as standard normal under the null for large N (number of groups) and large T (number of time periods). Monte Carlo results support the use of join asymptotic limits (under further condition that N/T ? 0) as a guide to finite sample performance, but also clearly indicate that the power of our suggested panel-based test is substantially higher than that of the single time series-based test.Mean Group Tests, Heterogeneous Panels, Joint Asymptotic Theory, Stationarity, Unit Roots, Monte Carlo Simulation, Finite Sample Adjustment.

Testing for Cointegration in Nonlinear STAR Error Correction Models

In this paper we propose a new testing procedure to detect the presence of a cointegrating relationship that follows a globally stationary smooth transition autoregressive (STAR) process. We start from a general VAR model, embed the STAR error correction mechanism (ECM) and then derive the generalised nonlinear STAR error correction model. We provide two operational versions of the tests. Firstly, we obtain the associated nonlinear ECM-based test. Secondly, we generalise the well-known residual-based test for cointegration in linear models by Engle and Granger (1987) and obtain its nonlinear analogue. We derive the relevant asymptotic distributions of the proposed tests. We find via Monte Carlo simulation exercises that our proposed tests have much better power than the Engle and Granger test against the alternative of a globally stationary STAR cointegrating process. In an application to the price-dividend relationship, we also find that our test is able to find cointegration, whereas the linear-based tests fail to do so. Further analysis of impulse response functions of error correction terms (under the alternative) shows that the time taken to recover one half of a one standard deviation shock varies between five and twenty years, whereas the time taken to recover one half of a large shock varies between just 4 to 18 months. This clearly implies that data periods dominated by extreme volatility may display substantial mean reversion of the price-dividend relationship. By contrast this relationship may well look like a unit root when the underlying shocks take on smaller values.Unit roots, Globally stationary cointegrating processes, Nonlinear exponential smooth transition autoregressive error correction models, Monte Carlo simulations, Prices and dividends

Machine-Learning Based Smoke Detection

A machine learning based arrangement can be used to more accurately detect whether a smoke alarm should be sounded based on a determined rate of change in the measured amount of smoke. The machine learning model may be pre-trained based on training data then executed by a smoke detector to accurately distinguish between likely emergencies and nuisance conditions

A Panel Data Approach to Testing Anomaly Effects in Factor Pricing Models

There has been a large anomaly literature where firm specific characteristics such as earnings-to-price ratio and book-to-market ratio as well as size help explain cross sectional returns. These anomalies that have been attributed to market inefficiency could be the result of a misspecification of the underlying factor pricing model. The most popular approach to detecting these anomaly effects has been the two pass (TP) cross-sectional regression models, advanced by Black, Jensen and Scholes (1972) and Fama and MacBeth (1973). However, it is well-established that the TP method suffers from the errors in variables problem, because estimated betas are used in the second stage cross sectional regression. In this paper we address the issue of testing for factor price misspecification via the panel data approach. Perhaps one of the main reasons for the neglect of benefits of using panel data technique is that in factor pricing models, all betas are heterogeneous in the first pass time series regression. However, if our interest lies solely in testing the significance of the firm's characteristics in factor pricing models, we can show how to construct a theoretically coherent example to which panel data techniques dealing with both homogeneous and heterogeneous parameters can be applied. Panel-based anomaly tests have one clear advantage over TP-based tests; they are based on full information maximum likelihood estimates so that they do not su®er from the errors in variable problem and have all the usual asymptotic properties associated with likelihood tests. The empirical illustration shows the importance of Book-to-Market equity and market value in helping explain asset returns even in the three factor models.Excess returns, market efficiency, anomaly effects, pooled ML estimation.

Introduction to customized occupational safety and health website and its effectiveness in improving psychosocial safety climate (PSC) among police officers

Introduction: The prevalence of stress among Malaysian police is high in which 38.8% polices have severe stress related to work resources and workplace environment. Psychosocial safety climate is one of the indicators that can be used to avoid psychosocial health problems. Objective: This study was conducted to determine the risk factors of psychosocial safety climate and to measure the effectiveness of a customised safety website in improving the safety climate. Methodology: This study involved 105 police officers who were randomly selected from nine different departments in PDRM Bukit Aman. A survey adapted from previous study was used to determine the psychosocial safety climate levels among respondents. Then, occupational safety website was introduced to the respondents and being used for two weeks. Lastly, post survey was done to see the difference of psychosocial safety climate before and after the use of the website. Results and Discussion: Findings showed that team psychological safety (r=0.381, p=<0.001) and physical safety climate (r=0.657, p=<0.001) were significantly associated with psychosocial safety climate level. The means before (36.095 ± 5.6202) and after (37.742 ± 4.7069) the introduction of occupational safety website was good. Still, there was a significant improvement of psychosocial safety climate level after the introduction of occupational safety website. Conclusion: This study showed that psychosocial safety climate level in an organization can be improved by introducing an informative website specific for police

Polarization controllable Fresnel lens using dye-doped liquid crystals

A scattering-free, polarization controllable Fresnel zone plate lens is demonstrated using a photo-induced alignment of the dye-doped liquid crystal film. This photo-aligned liquid crystal zone plate provides orthogonal polarization states for odd and even zones. The different focus orders can be separated because of their different polarization states. The fabrication process is relatively simple and the operation voltage is less than 5 V-rms

NASA - GRC Materials Research Activities in High Voltage High Frequency Power Transmission Systems for Electrified Aircraft

This presentation describes the NASA GRC Multifunctional Materials Team activities in high voltage materials testing capabilities build up and recent research activities

The BAF chromatin remodelling complex is an epigenetic regulator of lineage specification in the early mouse embryo.

Dynamic control of gene expression is essential for the development of a totipotent zygote into an embryo with defined cell lineages. The accessibility of genes responsible for cell specification to transcriptional machinery is dependent on chromatin remodelling complexes such as the SWI\SNF (BAF) complex. However, the role of the BAF complex in early mouse development has remained unclear. Here, we demonstrate that BAF155, a major BAF complex subunit, regulates the assembly of the BAF complex in vivo and regulates lineage specification of the mouse blastocyst. We find that associations of BAF155 with other BAF complex subunits become enriched in extra-embryonic lineages just prior to implantation. This enrichment is attributed to decreased mobility of BAF155 in extra-embryonic compared with embryonic lineages. Downregulation of BAF155 leads to increased expression of the pluripotency marker Nanog and its ectopic expression in extra-embryonic lineages, whereas upregulation of BAF155 leads to the upregulation of differentiation markers. Finally, we show that the arginine methyltransferase CARM1 methylates BAF155, which differentially influences assembly of the BAF complex between the lineages and the expression of pluripotency markers. Together, our results indicate a novel role of BAF-dependent chromatin remodelling in mouse development via regulation of lineage specification.We are grateful to: W. Xu for an antibody against methylated BAF155; R. Kemler for an antibody against Troma1, A. Surani for TS cells, P. Almeida Coelho, S. Vuoristo and A. Hupalowska for technical assistance; M. Bredford for the CARM1 -/- line; D. Glover, M-E Torres-Padilla, P. P. Amaral, K. Miyamoto, A. Bruce, I. Bedzhov and J. Gurdon for helpful suggestions. This work was supported by The Wellcome Trust Senior Fellowship to MZG; M.P. is supported by the Darwin Trust of Edinburgh.This is the final version of the article. It first appeared from The Company of Biologists via https://doi.org/10.1242/dev.13196