Three-Dimensional Magnetohydrodynamics Simulations Of Counter-Helicity Spheromak Merging In The Swarthmore Spheromak Experiment

Recent counter-helicity spheromak merging experiments in the Swarthmore Spheromak Experiment (SSX) have produced a novel compact torus (CT) with unusual features. These include a persistent antisymmetric toroidal magnetic field profile and a slow, nonlinear emergence of the n = 1 tilt mode. Experimental measurements are inconclusive as to whether this unique CT is a fully merged field-reversed configuration (FRC) with strong toroidal field or a partially merged doublet CT configuration with both spheromak- and FRC-like characteristics. In this paper, the SSX merging process is studied in detail using three-dimensional resistive MHD simulations from the Hybrid Magnetohydrodynamics (HYM) code. These simulations show that merging plasmas in the SSX parameter regime only partially reconnect, leaving behind a doublet CT rather than an FRC. Through direct comparisons, we show that the magnetic structure in the simulations is highly consistent with the SSX experimental observations. We also find that the n = 1 tilt mode begins as a fast growing linear mode that evolves into a slower-growing nonlinear mode before being detected experimentally. A simulation parameter scan over resistivity, viscosity, and line-tying shows that these parameters can strongly affect the behavior of both the merging process and the tilt mode. In fact, merging in certain parameter regimes is found to produce a toroidal-field-free FRC rather than a doublet CT. (C) 2011 American Institute of Physics. [doi:10.1063/1.3660533

Challenges and Successes Managing Eurasian Watermilfoil in Lake Luzerne: A 25 Year Citizen-Government Partnership

A 25-year, grassroots initiative to manage the spread of Eurasian watermilfoil, an invasive aquatic plant, in a Southern Adirondack lake is described. A dedicated group of long-term volunteers, together with local government and lake association support, employed a variety of management methods to control the Eurasian watermilfoil, keeping the lake attractive for recreational use. The management methods, volunteer effort, funding, and outcome for each epoch are included, along with keys to success, lessons learned, and future challenges

Mental Health Status and Perceived Barriers to Seeking Treatment in Rural Reserve Component Veterans

National Guard and Reserve (RC) troops (N=617) primarily from the Appalachian Region in Southwestern Pennsylvania who recently returned from deployment in support of current military conflicts responded to a survey that assessed their demographics, mental health symptoms, help-seeking behaviors, barriers for not seeking treatment, deployment history, and stressors. Veterans were classified as rural (N = 334) or non-rural (N = 283). Rural participants reported a significantly greater number of issues with transportation/access in seeking mental health treatment, were more likely to perceive others as worse off as a reason not to seek treatment, had a more negative attitude toward seeking treatment for mental health problems, and reported fewer concerns about a mental health problem affecting their career. Recommendations for mental health care providers and policymakers are offered based on the results, including the importance of recognizing the distinctive barriers to care that RC Appalachian veterans face when they come back into civilian communities, many of them rural

Why Compact Tori For Fusion?

A compact torus (CT) has a toroidal magnetic and plasma geometry, but is contained within a simply-connected vacuum vessel such as a cylinder. Spheromaks and field-reversed configurations fall into this category. Compact tori are translatable and have a high engineering beta. The primary benefit of CTs for fusion is the absence of toroidal field and Ohmic Heating coils and the many problems brought on by them. Studying fusion-relevant plasma in simply-connected geometries affords the world fusion program both physics and technology opportunities not found in other configurations. This paper outlines the technology and physics opportunities of compact tori, and presents a cost model based on geometry for comparison with less compact configurations

First recorded outbreak of Veronaea botryosa in North American amphibians: Clinicopathologic features of a rare cause of phaeohyphomycosis in captive White’s tree frogs (Litoria caerulea)

We describe fatal phaeohyphomycosis due to Veronaea botryosa in captive White’s tree frogs (Litoria caerulea), the first confirmed report in amphibians in North America. Over 15 months, six frogs developed ulcerative dermatitis on distal extremities/ventrum, which in one animal progressed to vasculitis and necrotizing osteomyelitis. All six frogs died. Clinicopathologic findings, diagnostic challenges, and control are discussed. Emerging fungi such as V. botryosa pose serious concerns for zoonosis and potential spread through the pet trade

Device Closure of Secundum Atrial Septal Defects in Children <15 kg Complication Rates and Indications for Referral

ObjectivesThis study sought to determine institutional complication rates in a previously underreported patient population and discuss referral indications.BackgroundThere has been a trend over the years for referral of younger and smaller patients for “elective” closure of atrial septal defects (ASD). In general, the risks associated with ASD device closure are believed and reported to be relatively low. Complication rates in this group of smaller patients are not well described in the literature for either percutaneous or surgical approaches.MethodsRetrospective review of all patients who underwent elective transcatheter closure of secundum ASD between March 2000 and April 2010. We excluded all children >15 kg, as well as those with complex congenital heart defects. Major and minor complications were predefined and indications for referral were evaluated.ResultsWe identified 128 patients meeting criteria with a median procedural age of 1.92 years (3 months to 4.92 years), and median weight of 10.8 kg (4.3 to 14.9 kb). There were 7 major (5.5%) and 12 minor (9.4%) complications. Nearly two-thirds of referrals were for right heart enlargement or poor growth. Rate of resolution of residual shunt was 99%. When compared with age, there was no difference in the rate of resolution of right heart enlargement. No clinically significant improvement in growth was observed.ConclusionsTranscatheter ASD closure in small children is highly successful, but with an increase in previously perceived complication rates. In small, asymptomatic patients, deferral of closure until the historically established timeline of around 4 to 5 years of age should be strongly considered

Genome-wide changes in protein translation efficiency are associated with autism

We previously proposed that changes in the efficiency of protein translation are associated with autism spectrum disorders (ASDs). This hypothesis connects environmental factors and genetic factors because each can alter translation efficiency. For genetic factors, we previously tested our hypothesis using a small set of ASD-associated genes, a small set of ASD-associated variants, and a statistic to quantify by how much a single nucleotide variant (SNV) in a protein coding region changes translation speed. In this study, we confirm and extend our hypothesis using a published set of 1,800 autism quartets (parents, one affected child and one unaffected child) and genome-wide variants. Then, we extend the test statistic to combine translation efficiency with other possibly relevant variables: ribosome profiling data, presence/absence of CpG dinucleotides, and phylogenetic conservation. The inclusion of ribosome profiling abundances strengthens our results for male–male sibling pairs. The inclusion of CpG information strengthens our results for female–female pairs, giving an insight into the significant gender differences in autism incidence. By combining the single-variant test statistic for all variants in a gene, we obtain a single gene score to evaluate how well a gene distinguishes between affected and unaffected siblings. Using statistical methods, we compute gene sets that have some power to distinguish between affected and unaffected siblings by translation efficiency of gene variants. Pathway and enrichment analysis of those gene sets suggest the importance of Wnt signaling pathways, some other pathways related to cancer, ATP binding, and ATP-ase pathways in the etiology of ASDs

Fish Bulletin 180. California Coastal Salmonid Population Monitoring: Strategy, Design, and Methods

California’s salmon and steelhead populations have experienced marked declines leading to listing of almost all of California’s anadromous salmonids under the California Endangered Species Act (CESA) and Federal Endan-gered Species Act (ESA). Both CESA and ESA listings require recovery plans that call for monitoring to provide some measure of progress toward recovery. In addition, there are related monitoring needs for other management activi-ties such as hatchery operations and fisheries management

Phosphatidylinositol 3-kinase signaling in proliferating cells maintains an anti-apoptotic transcriptional program mediated by inhibition of FOXO and non-canonical activation of NFκB transcription factors

<p>Abstract</p> <p>Background</p> <p>Phosphatidylinositol (PI) 3-kinase is activated by a variety of growth factor receptors and the PI 3-kinase/Akt signaling pathway is a key regulator of cell proliferation and survival. The downstream targets of PI 3-kinase/Akt signaling include direct regulators of cell cycle progression and apoptosis as well as a number of transcription factors. Growth factor stimulation of quiescent cells leads to robust activation of PI 3-kinase, induction of immediate-early genes, and re-entry into the cell cycle. A lower level of PI 3-kinase signaling is also required for the proliferation and survival of cells maintained in the presence of growth factors, but the gene expression program controlled by PI 3-kinase signaling in proliferating cells has not been elucidated.</p> <p>Results</p> <p>We used microarray analyses to characterize the changes in gene expression resulting from inhibition of PI 3-kinase in proliferating cells. The genes regulated by inhibition of PI 3-kinase in proliferating cells were distinct from genes induced by growth factor stimulation of quiescent cells and highly enriched in genes that regulate programmed cell death. Computational analyses followed by chromatin immunoprecipitations demonstrated FOXO binding to both previously known and novel sites in promoter regions of approximately one-third of the up-regulated genes, consistent with activation of FOXO1 and FOXO3a in response to inhibition of PI 3-kinase. NFκB binding sites were similarly identified in promoter regions of over one-third of the down-regulated genes. RelB was constitutively bound to promoter regions in cells maintained in serum, however binding decreased following PI 3-kinase inhibition, indicating that PI 3-kinase signaling activates NFκB via the non-canonical pathway in proliferating cells. Approximately 70% of the genes targeted by FOXO and NFκB regulate cell proliferation and apoptosis, including several regulators of apoptosis that were not previously known to be targeted by these transcription factors.</p> <p>Conclusion</p> <p>PI 3-kinase signaling in proliferating cells regulates a novel transcriptional program that is highly enriched in genes that regulate apoptosis. At least one-third of these genes are regulated either by FOXO transcription factors, which are activated following PI 3-kinase inhibition, or by RelB, which is activated by PI 3-kinase via the non-canonical pathway in proliferating cells.</p

Dipole Trapped Spheromak In A Prolate Flux Conserver

This paper reports the observation and characterization of a spheromak formed in the Swarthmore Spheromak Experiment (SSX, [M. R. Brown, Phys. Plasmas 6, 1717 (1999)]) and trapped in a simple dipole magnetic field. The spheromak is studied in a prolate (tilt unstable) 0.4 m diameter, 0.6 m length copper flux conserver in SSX. This plasma does not tilt, despite the prolate flux conserver. The spheromak is characterized by a suite of magnetic probe arrays for magnetic structure B(r,t), ion Doppler spectroscopy for T-i and flow, and interferometry for n(e). Three-dimensional magnetohydrodynamics simulations of this configuration verify its gross sta-bility. (c) 2006 American Institute of Physics