Mesoscopic Effects in the Fractional Quantum Hall Regime: Chiral Luttinger versus Fermi Liquid

We study tunneling through an edge state formed around an antidot in the fractional quantum Hall regime using Wen's chiral Luttinger liquid theory extended to include mesoscopic effects. We identify a new regime where the Aharonov-Bohm oscillation amplitude exhibits a distinctive crossover from Luttinger liquid power-law behavior to Fermi-liquid-like behavior as the temperature is increased. Near the crossover temperature the amplitude has a pronounced maximum. This non-monotonic behavior and novel high-temperature nonlinear phenomena that we also predict provide new ways to distinguish experimentally between Luttinger and Fermi liquids.Comment: 13 pages, Revtex, Figure available from [email protected]

Home Mirror Therapy: A Randomized Control Study Comparing Unimanual and Bimanual Mirror Therapy for Improved Arm and Hand Function Post-stroke

Stroke is the leading cause of disability in the United States. The majority of stroke survivors have persistent arm dysfunction, which impedes their daily task performance. Mirror therapy (MT) as an adjunct to occupational therapy (OT) has been shown to be effective in upper extremity (UE) recovery post-stroke. Two protocols, unimanual mirror therapy (UMT) and bimanual mirror therapy (BMT), have been used in OT practice; however, research specifically comparing these two intervention protocols is absent. The purpose of this study was to compare: (a) home-based UMT and BMT protocols, and (b) both MT protocols to home-based traditional occupational therapy (TOT) regarding upper limb recovery post-stroke. Twenty-two chronic stroke participants were randomized into one of three groups: UMT, BMT, or TOT. The Action Research Arm Test (ARAT), Fugl-Meyer Assessment (FMA), ABILHAND, grip strength, and the Stroke Impact Scale (SIS) were administered pre- and post-intervention. Participants received outpatient OT 2 days/week for 45 minutes, plus a home program 30 minutes a day, 5 days/week for 6 weeks. A repeated measure ANOVA, Kruskal-Wallis Test, and Wilcoxon Ranked-Signed Test were used to compare the three groups, and 95% confidence intervals (CI) and effect sizes were calculated. There was a main effect of time for all groups, except for SIS-strength and activities of daily living (ADL); however, no group differences were noted on any of the measures. When comparing UMT and BMT, the effect size for all measures, except for grip strength, favored UMT. In comparing both mirror groups to TOT, UMT had a moderate to large effect size on the ARAT, FMA, and ABILHAND, as compared to the small effect size for BMT. Furthermore, 95% CI data for the ABILHAND showed clinical significance in favor of UMT compared to TOT, but not for BMT. This study showed that all groups improved over time and UMT may be more beneficial for UE recovery in chronic stroke individuals, compared to either BMT or TOT. However, given the small sample size, future studies comparing the two mirror protocols are necessary for more definitive conclusions to better inform clinicians of the optimal mode of MT treatment

A Morphology--Cosmology Connection for X--Ray Clusters

We employ N--body/$3D$ gas dynamic simulations of the formation of galaxy clusters to determine whether cluster X--ray morphologies can be used as cosmological constraints. Confirming the analytic expectations of Richstone, Loeb, \& Turner, we demonstrate that cluster evolution is sensitive to the cosmological model in which the clusters form. We further show that evolutionary differences are echoed in the gross morphological features of the cluster X--ray emission. We examine current--epoch X--ray images of models originating from the same initial density fields evolved in three different cosmologies: (i) an unbiased, low density universe with \Omega_o \se 0.2; (ii) an unbiased universe dominated by vacuum energy with \Omega_o \se 0.2 and \lambda_o \se 0.8 and (iii) a biased Einstein--deSitter model (\Omega \se 1, $\sigma_8=0.59$). Using measures of X--ray morphology such as the axial ratio and centroid shifting, we demonstrate that clusters evolved in the two low $\Omega_o$ models are much more regular, spherically symmetric, and centrally condensed than clusters evolved in the Einstein--deSitter model. This morphology--cosmology connection, along with the availability of a large body of cluster X--ray observations, makes cluster X--ray morphology both a powerful and a practical cosmological discriminant.Comment: (uuencoded, compressed postscript, 9 pages including figures), CFA-370

A Complete Spectroscopic Census of Abell 2029: A Tale of Three Histories

A rich spectroscopic census of members of the local massive cluster Abell 2029 includes 1215 members of A2029 and its two infalling groups, A2033 and a Southern Infalling Group (SIG). The two infalling groups are identified in spectroscopic, X-ray and weak lensing maps. We identify active galactic nuclei (AGN), star-forming galaxies, E+A galaxies, and quiescent galaxies based on the spectroscopy. The fractions of AGN and post-starburst E+A galaxies in A2029 are similar to those of other clusters. We derive the stellar mass ($M_{*}$)-metallicity of A2029 based on 227 star-forming members; A2029 members within $10^{9} M_{\odot} < M _{*} < 10^{9.5} M_{\odot}$ are more metal rich than SDSS galaxies within the same mass range. We utilize the spectroscopic index $D_{n}4000$, a strong age indicator, to trace past and future evolution of the A2029 system. The median $D_{n}4000$ of the members decreases as the projected clustercentric distance increases for all three subsystems. The $D_{n}4000 - M_{*}$ relations of the members in A2029 and its two infalling groups differ significantly indicating the importance of stochastic effects for understanding the evolution of cluster galaxy populations. In the main cluster, an excess around $D_{n}4000 \sim 1.8$ indicates that some A2029 members became quiescent galaxies 2-3 Gyr ago consistent with the merger epoch of the X-ray sloshing pattern.Comment: 17 pages, 11 figures, submitted to Ap

Applying Kolb\u27s Theory to Distance Learning

Recent advances in technology have brought major changes in pedagogy methods. Distance Learning (DL) has emerged as an innovative teaching method and it is becoming very popular in today’s education. We study a business simulation game in a DL environment and examine the learning outcomes and benefits of using the game in this environment. We also compare our test results to a game conducted in a traditional face-to-face class. Our findings show that students do not consider the DL teaching method to be worst than the traditional one. However, technical difficulties deterred the students to declare this method s superior. We conclude that further study of DL is necessary to: (1) realize its benefits; and (2) address the many challenges the creation of a DL learning environment poses

Practice Parameter for the Assessment and Treatment of Children and Adolescents With Obsessive-Compulsive Disorder

Research in etiology, neurobiology, genetics, clinical correlates, and evidence-based treatments in children and adolescents with obsessive-compulsive disorder indicate a need for the revision of the Practice Parameters for the Assessment and Treatment of Children and Adolescents with Obsessive-Compulsive Disorder first published a decade ago. The present article highlights the clinical assessment and reviews and summarizes the evidence base for treatment. Based on this evidence, specific recommendations are provided for assessment, cognitive behavioral therapy, pharmacotherapy, combined treatment, and other interventions

Novel approaches in treatment of pediatric anxiety

Pediatric anxiety disorders have high prevalence rates and morbidity and are associated with considerable functional impairment and distress. They may be predictors for the development of other psychiatric disorders and, without intervention, are more likely to persist into adulthood. While evidence-based pharmacological and behavioral interventions are currently available, there remains a sizable subset of youth who remain only partially treatment-responsive and therefore symptomatic following treatment. Novel methods of treatment, pharmacologic and non-pharmacologic, including acceptance and commitment therapy (ACT), attention bias modification (ABM), d-cycloserine (DCS) augmentation of cognitive behavioral treatment (CBT), and glutamatergic agents such as riluzole, are briefly introduced and discussed