Eigenvalue Separation in Some Random Matrix Models

The eigenvalue density for members of the Gaussian orthogonal and unitary ensembles follows the Wigner semi-circle law. If the Gaussian entries are all shifted by a constant amount c/Sqrt(2N), where N is the size of the matrix, in the large N limit a single eigenvalue will separate from the support of the Wigner semi-circle provided c > 1. In this study, using an asymptotic analysis of the secular equation for the eigenvalue condition, we compare this effect to analogous effects occurring in general variance Wishart matrices and matrices from the shifted mean chiral ensemble. We undertake an analogous comparative study of eigenvalue separation properties when the size of the matrices are fixed and c goes to infinity, and higher rank analogues of this setting. This is done using exact expressions for eigenvalue probability densities in terms of generalized hypergeometric functions, and using the interpretation of the latter as a Green function in the Dyson Brownian motion model. For the shifted mean Gaussian unitary ensemble and its analogues an alternative approach is to use exact expressions for the correlation functions in terms of classical orthogonal polynomials and associated multiple generalizations. By using these exact expressions to compute and plot the eigenvalue density, illustrations of the various eigenvalue separation effects are obtained.Comment: 25 pages, 9 figures include

Inverted orbital polarization in strained correlated oxide films

Manipulating the orbital occupation of valence electrons via epitaxial strain in an effort to induce new functional properties requires considerations of how changes in the local bonding environment affect the band structure at the Fermi level. Using synchrotron radiation to measure the x-ray linear dichroism of epitaxially strained films of the correlated oxide CaFeO3, we demonstrate that the orbital polarization of the Fe valence electrons is opposite from conventional understanding. Although the energetic ordering of the Fe 3d orbitals is confirmed by multiplet ligand field theory analysis to be consistent with previously reported strain-induced behavior, we find that the nominally higher energy orbital is more populated than the lower. We ascribe this inverted orbital polarization to an anisotropic bandwidth response to strain in a compound with nearly filled bands. These findings provide an important counterexample to the traditional understanding of strain-induced orbital polarization and reveal a new method to engineer otherwise unachievable orbital occupations in correlated oxides

The Role of Culture, Family Processes, and Anger Regulation in Korean American Adolescents’ Adjustment Problems

Using an ecologically informed, developmental psychopathology perspective, the present study examined contextual and intrapersonal predictors of depressive symptoms and externalizing problems among Korean American adolescents. Specifically, the role of cultural context (selfconstruals), family processes (family cohesion and conflict), and anger regulation (anger control, anger suppression, and outward anger expression) were examined. Study participants were N = 166 Korean American adolescents ranging from 11-15 (M = 13.0; SD = 1.2) years old. Results showed that depressive symptoms were significantly associated with lower levels of perceived family cohesion, higher levels of perceived family conflict intensity, and higher levels of anger suppression. Externalizing problems were associated with male gender, a weaker interdependent self-construal, higher levels of perceived family conflict, lower levels of anger control, and higher levels of outward anger expression. The distinction between specific vs. common factors associated with depressive symptoms and externalizing problems was discussed with an eye towards prevention or intervention strategies targeting specific coping mechanisms (e.g., generating alternatives to anger suppression) or developing psychoeducational approaches to facilitate family processes

Further insights into aspects of the EU illicit drugs market: summaries and key findings

This publication presents key findings and summaries of selected reports from the study ‘Further insights into aspects of the EU illicit drugs market’ (Trautmann, Kilmer and Turnbull, forthcoming 2013), which provides an analysis of characteristics and operations of the EU’s illicit drugs market, as called for by the European Commission. This study is a follow-up of the earlier European Commission study, which presented an analysis of the developments of the global illicit drug markets, the drug problems and drug policy responses in the period 1998-2007 (Reuter and Trautmann 2009). The discussions of that study resulted in a number of further research questions. Some of the questions considered most important by the European Commission have been put together in a call for a further analysis of the EU illicit drugs market and responses to it, focusing on a number of aspects in the following four areas: A. An analysis of specific characteristics, mechanisms and factors that govern the EU illicit drugs market, including a conceptual framework for thinking about the structure of drug suppliers in the EU, an assessment whether there have been significant shifts in how drugs are supplied in the EU and an assessment of the extent to which drug suppliers are involved in different drugs and other criminal activities. B. A detailed analysis of the size and share of the EU illicit drug market, providing an estimate of the volume of the ‘EU market’ in illicit drugs (production and trafficking), providing an estimate of the profits generated by this market, analysing whether the EU drugs market is more supply or demand driven and exploring various aspects of drug use: user types, availability and consumption estimates. C. A detailed analysis of a number of potential policy impacts on the EU drug market(s) in recent years, assessing the impact of opioid substitution treatment (OST) on the European heroin market and the impact of policy changes on two EU drug markets. D. Scanning the future – trends in the market and policy responses, exploring expert views on future key trends of the illicit drug markets and policy responses in the EU

Creating a National Coalition to Address Tractor Overturn Fatalities.

Tractor overturns continue to be the leading cause of death on U.S. farms. While rollover protective structures (ROPS) are effective in preventing these fatalities, they are underutilized due to a number of barriers. Past programs in the U.S. and abroad have targeted this area of agricultural safety; however, a national program is not yet in place for U.S. farmers. This study seeks to build a national partnership to address tractor overturn fatalities by increasing the number of tractors with ROPS. A diverse, multisector steering committee has been organized and is working together using Whole System in a Room methods. This method brings together partners from nine stakeholder groups to identify and commit to a collaborative solution to the issue

A perioculomotor nitridergic population in the macaque and cat

Purpose. To determine the distribution of cells containing synthetic enzymes for the unconventional neurotransmitter, nitric oxide, with respect to the known populations within the oculomotor complex. Methods. The oculomotor complex was investigated in monkeys and cats by use of histochemistry to demonstrate nicotinamide adenine dinucleotide phosphate diaphorase positive (NADPHd+) cells and antibodies to localize neuronal nitric oxide synthase positive (NOS+) cells. In some cases, wheatgerm agglutinin conjugated horseradish peroxidase (WGA-HRP) was injected into extraocular muscles to allow comparison of retrogradely labeled and NADPHd+ cell distributions. Results. The distribution of the NADPHd+ and NOS+ neurons did not coincide with that of preganglionic and extraocular motoneurons in the oculomotor complex. However, labeled perioculomotor neurons were observed. Specifically, in monkeys, they lay in an arc that extended from between the oculomotor nuclei into the supraoculomotor area (SOA). Comparison of WGA-HRP labeled medial and superior rectus motoneurons with NADPHd staining confirmed that the distributions overlapped, but showed that the C- and S-group cells were not NADPHd+. This suggested that NADPHd+ cells are part of the centrally projecting Edinger-Westphal population (EWcp). Examination of the NADPHd+ cell distribution in the cat showed that these cells were indeed found primarily within its well-defined EWcp. Conclusions. Based on their similar distributions, it appears that the peptidergic EWcp neurons, which project widely in the brain, may also be nitridergic. While the preganglionic and C- and S- group motoneuron populations do not utilize this non-synaptic neurotransmitter, nitric oxide produced by surrounding NADPHd+ cells may modulate the activity of these motoneurons

The pupillary and ciliary components of the cat Edinger-Westphal nucleus: a transsynaptic transport investigation

The distribution of preganglionic motoneurons supplying the ciliary ganglion in the cat was defined both qualitatively and quantitatively. These cells were retrogradely labeled directly, following injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the ciliary ganglion, or were transsynaptically labeled following injections of WGA into the vitreous chamber. Almost half of the cells are distributed rostral to the oculomotor nucleus, both in and lateral to the anteromedian nucleus. Of the remaining preganglionic motoneurons, roughly 20% of the total are located dorsal to the oculomotor nucleus. Strikingly few of these neurons are actually found within the Edinger-Westphal nucleus proper. Instead, the majority are found in the adjacent supraoculomotor area or along the midline between the two somatic nuclei. An additional population, roughly 30% of the total, is located ventral to the oculomotor nucleus. This study also provides evidence for a functional subdivision of this preganglionic population. Pupil-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the anterior chamber, while lens-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the ciliary muscle. The results suggest that the pupil-related preganglionic motoneurons, that is, those controlling the iris sphincter pupillae muscle, are located rostrally, in and lateral to the anteromedian nucleus. In contrast, lens-related preganglionic motoneurons, that is, those controlling the ciliary muscle are particularly prevalent caudally, both dorsal and ventral to the oculomotor nucleus. Thus, the cat intraocular muscle preganglionic innervation is spatially organized with respect to function, despite the dispersed nature of its distribution

Using Light Charged Particles to Probe the Asymmetry Dependence of the Nuclear Caloric Curve

Recently, we observed a clear dependence of the nuclear caloric curve on neutron-proton asymmetry $\frac{N-Z}{A}$ through examination of fully reconstructed equilibrated quasi-projectile sources produced in heavy ion collisions at E/A = 35 MeV. In the present work, we extend our analysis using multiple light charged particle probes of the temperature. Temperatures are extracted with five distinct probes using a kinetic thermometer approach. Additionally, temperatures are extracted using two probes within a chemical thermometer approach (Albergo method). All seven measurements show a significant linear dependence of the source temperature on the source asymmetry. For the kinetic thermometer, the strength of the asymmetry dependence varies with the probe particle species in a way which is consistent with an average emission-time ordering.Comment: 7 pages, 4 figure