TRUE STATE DEPENDENCE IN MONTHLY WELFARE PARTICIPATION:A NONEXPERIMENTAL ANALYSIS

This paper provides an empirical evaluation of true state dependence in welfare participation using unique administrative data from California that is measured at the monthly frequency, which coincides with the welfare eligibility period and so is free of time aggregation bias. The analysis uses first- and second-order dynamic conditional logit models that non-parametrically control for permanent unobserved heterogeneity to test for state dependence in welfare behavior. The second-order model also absorbs individual-specific first-order Markov chains, and provides a more robust test for state dependence in high frequency data. The results using the first-order model show substantial first-order state dependence in monthly welfare participation. Absorbing heterogeneous first-order effects, the hypothesis of no second-order state dependence is also easily rejected. This suggests that past welfare participation predicts future participation, given unrestricted effects of both the present state and unobserved heterogeneity, and provides substantive evidence of duration dependence at the individual level.Binary response panel data, state dependence, unobserved heterogeneity, initialconditions, conditional logit models

Lecture videos to supplement electromagnetic classes at Cal Poly San Luis Obispo

Electromagnetics and Transmission Lines is a fundamental, yet difficult subject in the Electrical Engineering (EE) field. To help improve information retention, a series of lecture videos was created to supplement traditional lectures, to facilitate in-class discussions, and to improve students’ proficiency and interest in electromagnetics. Engineering electromagnetics classes at California Polytechnic State University, San Luis Obispo cover fundamentals to understand and analyze cell phone communications, radar systems (air traffic control, law enforcement), and biomedical imaging (MRI). However, this subject also requires considerable mathematics preparation in vector calculus, differential equations, linear algebra, and background in both physics and EE. Lecture videos were created on the Camtasia software to produce MP4 audio-visual files. All videos include a topic outline, stationary and animated visual displays of lecture topic applications, and a detailed discussion using outlines and handwritten notes. Example calculations and real-world applications, Smith Chart graphical analysis, and Matlab computations and visual animations (standing and traveling waves, dynamic vector field and scalar contour diagrams) augment theoretical discussions and help visualize course concepts. Real-world applications including the Large Hadron Collider (CERN), RF test equipment (network analyzers), cell phone tower antennas, and radar imaging systems are introduced in the videos and related to course topics. A total of 36 videos were recorded for EE 335 (junior-level electromagnetics); average video length is 20 to 25 minutes for each 50 minute lecture. All lecture videos were stored online (dropbox.com) and made available one week prior to each class session. A student survey was conducted to assess perceived video effectiveness, to compare to traditional lectures, and to estimate video usage (how often watched, how many hours per week). Questions also include overall suggestions for video improvement, favorite (and not so favorite) parts of the class, and overall impressions. Most students appeared to value the new videos: 55% agreed with the statement “the lecture videos helped me learn course concepts.” Video length (20 – 25 minute average) was between too long (43%) and just right (29%). The most common negative comment mentioned the additional time required to view the videos over a traditional lecture class. Future efforts toward a flipped (inverted) classroom format include the development of topic videos and post-video quizzes to encourage pre-lecture viewing, as suggested in [1]. Video production improvements including minimized length and enhanced information organization will be applied to future lecture videos. Practical lab projects [2] will also be explored and added as another method of enhancing student interest in electromagnetics. Finally, information retention between traditional and flipped classroom formats will be compared to determine the relative effectiveness of both approaches

An Investigation, Using Standard Experimental Techniques, to Determine FLCs at Elevated Temperature for Aluminium Alloys

An experimental procedure has been developed for the determination of FLCs at elevated temperatures. The GOM ARGUS system was employed for measuring surface strain based on pre-applied grids (pattern), and limit strains were determined according to the ISO 12004-2:2008 standard. Forming limit curves (FLCs) have been determined for AA5754 under warm forming conditions in an isothermal environment. The tests were carried out at various temperatures up to 300oC and forming speeds ranging from 5 – 300 mm s-1 . Results reveal the significant effect of both temperature and forming speed on FLCs of AA5754. Formability increases with increasing temperature above 200oC. Formability also increases with decreasing speed. The presented FLC results show that the best formability exists at low forming speed and the high temperature end of the warm forming range

Large Deviations of Extreme Eigenvalues of Random Matrices

We calculate analytically the probability of large deviations from its mean of the largest (smallest) eigenvalue of random matrices belonging to the Gaussian orthogonal, unitary and symplectic ensembles. In particular, we show that the probability that all the eigenvalues of an (N\times N) random matrix are positive (negative) decreases for large N as \exp[-\beta \theta(0) N^2] where the parameter \beta characterizes the ensemble and the exponent \theta(0)=(\ln 3)/4=0.274653... is universal. We also calculate exactly the average density of states in matrices whose eigenvalues are restricted to be larger than a fixed number \zeta, thus generalizing the celebrated Wigner semi-circle law. The density of states generically exhibits an inverse square-root singularity at \zeta.Comment: 4 pages Revtex, 4 .eps figures included, typos corrected, published versio

Extreme Value Statistics of Eigenvalues of Gaussian Random Matrices

We compute exact asymptotic results for the probability of the occurrence of large deviations of the largest (smallest) eigenvalue of random matrices belonging to the Gaussian orthogonal, unitary and symplectic ensembles. In particular, we show that the probability that all the eigenvalues of an (NxN) random matrix are positive (negative) decreases for large N as ~\exp[-\beta \theta(0) N^2] where the Dyson index \beta characterizes the ensemble and the exponent \theta(0)=(\ln 3)/4=0.274653... is universal. We compute the probability that the eigenvalues lie in the interval [\zeta_1,\zeta_2] which allows us to calculate the joint probability distribution of the minimum and the maximum eigenvalue. As a byproduct, we also obtain exactly the average density of states in Gaussian ensembles whose eigenvalues are restricted to lie in the interval [\zeta_1,\zeta_2], thus generalizing the celebrated Wigner semi-circle law to these restricted ensembles. It is found that the density of states generically exhibits an inverse square-root singularity at the location of the barriers. These results are confirmed by numerical simulations.Comment: 17 pages Revtex, 5 .eps figures include

A Survival Model for Unthinned Loblolly Pine Plantations That Incorporates Non-Planted Tree Competition, Site Quality, and Incidence of Fusiform Rust

Future biomass yields are functionally related to the number of trees surviving at a given age. A stand level survival model was developed that incorporates competition of non-planted trees, site quality, and the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). The model consists of a system of two equations, one of which represents the number of surviving trees infected by fusiform rust while the other represents the number of trees not infected by fusiform rust. Data from unthinned loblolly pine (Pinus taeda L.) plantations in East Texas were used to fit and evaluate the survival model and illustrate its use. The model successfully predicted that the number of surviving loblolly pine trees decreased as the number of non-planted trees increased. The model also successfully predicted the transition of loblolly pine trees from an uninfected to an infected status by fusiform rust

Role of the aryl hydrocarbon receptor in Sugen 5416-induced experimental pulmonary hypertension

Rationale: Rats dosed with the vascular endothelial growth factor (VEGF) inhibitor Sugen 5416 (Su), placed in hypoxia then restored to normoxia has become a widely used model of pulmonary arterial hypertension (PAH). The mechanism by which Su exaccerbates pulmonary hypertension is, however, unclear. Objectives: We investigated Su-activation of the aryl hydrocarbon receptor (AhR) in patient human pulmonary arterial smooth muscle cells (hPASMCs) and patient blood outgrowth endothelial cells (BOECs). We also examined the effect of AhR on aromatase and estrogen levels in the lung. Methods, Measurements and Main Results: Protein and mRNA analysis demonstrated that CYP1A1 was very highly induced in the lungs of Su/hypoxic (Su/Hx) rats. The AhR antagonist CH223191 (8mg/kg/day) reversed the development of PAH in this model in vivo and normalized lung CYP1A1 expression. Increased lung aromatase and estrogen levels in Su/Hx rats were also normalized by CH223191 as was AhR nuclear translocator (ARNT [HIF-1β]) which is shared by HIF-1α and AhR. Su reduced HIF1α expression in hPASMCs. Su induced proliferation in BOECs and increased apoptosis in human pulmonary microvascular endothelial cells (hPMECs) and also induced translocation of AhR to the nucleus in hPASMCs. Under normoxic conditions, hPASMCs do not proliferate to Su. However when grown in hypoxia (1%) Su induced hPASMC proliferation. Conclusion: In combination with hypoxia, Su is proliferative in patient hPASMCs and patient BOECs and Su/Hx-induced PAH in rats may be facilitated by AhR-induced CYP1A1, ARNT and aromatase. Inhibition of the AhR receptor may be a novel approach to the treatment of pulmonary hypertension