On The Panel Unit Root Tests Using Nonlinear Instrumental Variables

This paper re-examines the panel unit root tests proposed by Chang (2002). She establishes asymptotic independence of the t-statistics when integrable functions of lagged dependent variable are used as instruments even if the original series are cross sectionally dependent. She claims that her non-linear instrumental variable (NIV) panel unit root test is valid under general error cross correlations for any N (the cross section dimension) as T (the time dimension of the panel) tends to infinity. These results are largely due to her particular choice of the error correlation matrix which results in weak cross section dependence. Also, the asymptotic independence property of the t- statistics disappears when Chang's modified instruments are used. Using a common factor model with a sizeable degree of cross section correlations, we show that Chang's NIV panel unit root test suffers from gross size distortions, even when N is small relative to T

Chiral Restoration in the Early Universe: Pion Halo in the Sky

vanishing above $T_c$ indicates chiral symmetry restoration at high $T$. But is it the old $T=0$ chiral symmetry that is `restored'? In this talk, I report on the spacetime quantization of the BPFTW effective action for quarks in a hot environ. The fermion propagator is known to give a pseudo-Lorentz invariant particle pole as well as new spacelike cuts. Our quantization shows that the spacelike cuts directly lead to a thermal vacuum that is a generalized NJL state, with a curious $90^{o}$ phase. This $90^{o}$ is responsible for vanishing at high $T$. The thermal vacuum is invariant under a new chiral charge, but continues to break the old zero temperature chirality. Our quantization suggests a new class of order parameters that probe the physics of these spacelike cuts. In usual scenario, the pion dissociates in the early alphabet soup. With this new understanding of the thermal vacuum, the pion remains a Nambu-Goldstone particle at high $T$, and will not dissociate. It propagates at the speed of light but with a halo.Comment: 4 pages, LaTeX, CCNY-HEP-94-9 To appear in Proceedings of "Trends in Astroparticle Physics Workshop", Stockholm, Sweden, 22-25 September, 1994, Nuclear Physics B, Proceedings Supplement, edited by L. Bergstrom, P. Carlson, P.O. Hulth, and H. Snellman. (Only revision is in the header citation

Optimizing genetics online resources for diverse readers.

PurposeClear and accurate genetic information should be available to health-care consumers at an individualized level of comprehension. The objective of this study is to evaluate the complexity of common online resources and to simplify text content using automated text processing tools.MethodsWe extracted all text from Genetics Home Reference and MedlinePlus in bulk and analyzed content using natural language processing. We applied custom tools to improve the readability and compared readability before and after text optimization.ResultsCommonly used educational materials were more complex than the recommended reading level for the general public. Genetic health information entries from Genetics Home Reference (n = 1279) were written at a median 13.0 grade level. MedlinePlus entries, which are not exclusively genetic (n = 1030), had a median grade level of 7.7. When we optimized text for the 59 actionable conditions by prioritizing medical details using a standard structure, the average reading grade level improved.ConclusionFactors that increase complexity are long sentences and difficult words. Future strategies to reduce complexity include prioritizing relevant details and using more illustrations. Simplifying and providing standardized online health resources would benefit diverse consumers and promote inclusivity

An idea for a new modeling approach of climatic changes. A correlation study for Cyprus

Mathematical Modeling in climatic changes prediction has been based on more or less simple energy balances considering the Earth along with its atmosphere, with the so-called solar "constant" taken as an invariant. However evidence has been supplied in previous WSEAS Conferences that this constant, S, does not remain a constant but it does fluctuate, following the cycles of the solar activity. Furthermore the transmission parameters concerning the input and the output energy, τ V and τ IR from/to the system Earth-Atmosphere also vary and this reflects the human activity leading to increased greenhouse gas quantities, being blamed for a dramatic climatic change the last decades. Thus, considering those fluctuating properties, the following equation for Earth's mean temperature, T, has been developed (A being albedo equal to 0.3 and σ is the Stefan-Boltzmann constant) (Equation presented) with the following multivariate treatment: (Equation presented) We need to obtain the derivatives: (Equation presented) because all S, τ IR, τ V chang