Magnetic Reconnection Triggered by the Parker Instability in the Galaxy: Two-Dimensional Numerical Magnetohydrodynamic Simulations and Application to the Origin of X-Ray Gas in the Galactic Halo

We propose the Galactic flare model for the origin of the X-ray gas in the Galactic halo. For this purpose, we examine the magnetic reconnection triggered by Parker instability (magnetic buoyancy instability), by performing the two-dimensional resistive numerical magnetohydrodynamic simulations. As a result of numerical simulations, the system evolves as following phases: Parker instability occurs in the Galactic disk. In the nonlinear phase of Parker instability, the magnetic loop inflates from the Galactic disk into the Galactic halo, and collides with the anti-parallel magnetic field, so that the current sheets are created in the Galactic halo. The tearing instability occurs, and creates the plasmoids (magnetic islands). Just after the plasmoid ejection, further current-sheet thinning occurs in the sheet, and the anomalous resistivity sets in. Petschek reconnection starts, and heats the gas quickly in the Galactic halo. It also creates the slow and fast shock regions in the Galactic halo. The magnetic field ($B\sim 3 \mu$G), for example, can heat the gas ($n\sim 10^{-3}$ cm$^{-3}$) to temperature of $\sim 10^6$ K via the reconnection in the Galactic halo. The gas is accelerated to Alfv\'en velocity ($\sim 300$ km s$^{-1}$). Such high velocity jets are the evidence of the Galactic flare model we present in this paper, if the Doppler shift of the bipolar jet is detected in the Galactic halo. Full size figures are available at http://www.kwasan.kyoto-u.ac.jp/~tanuma/study/ApJ2002/ApJ2002.htmlComment: 13 pages, 12 figures, uses emulateapj.sty, accepted by Ap

Resection Status, Age and Nodal Involvement Determine Survival among Patients Receiving Adjuvant Chemoradiotherapy in Pancreatic Adenocarcinoma

Context Pancreas cancer can potentially be cured by resection, but the role of adjuvant chemotherapy and/or chemoradiation has been controversial. Objectives To better define clinicopathological factors that may serve as predictive and/or prognostic variables. Patients Between 1984 and 2006, we retrospectively analyzed 91 patients with pancreas cancer treated with pancreaticoduodenectomy or total pancreatectomy followed by adjuvant 5-fluorouracil-based chemoradiation at the University of Pennsylvania. Final pathological coding including margin status was confirmed by a pathologist. Interventions Patients were treated with 48.6 to 63.0 Gy, and 96.7% completed their prescribed radiation dose. Main outcome measures The prognostic significance of demographic factors, stage, year of surgery, tumor location, grade, resection status, and number of positive lymph nodes on overall survival were examined. Results With a median follow-up of 6.5 years, the overall median survival was 2.3 years (95% CI 1.5-3.2 years), and the 5-year overall survival was 28.9%. In multivariate analysis, completeness of resection (P<0.001), fewer number of positive lymph nodes (0 vs. 1-2 vs. 3 or more) (P=0.004), and age less than, or equal to, 60 years (P=0.006) were all independently associated with improved overall survival. The overall survival reported in this study compares favorably with the results of other single-institution studies and with the RTOG 97-04 trial. Conclusions Adjuvant 5-FU-based chemoradiation following radical pancreatectomy can be delivered safely and results in comparatively good overall survival. The results of this analysis underscore the importance of resection status, number of involved lymph nodes and patient age as prognostic characteristics. These factors may be considered stratification variables for future post-pancreatectomy adjuvant therapy trials

Magnetoluminescence

Pulsar Wind Nebulae, Blazars, Gamma Ray Bursts and Magnetars all contain regions where the electromagnetic energy density greatly exceeds the plasma energy density. These sources exhibit dramatic flaring activity where the electromagnetic energy distributed over large volumes, appears to be converted efficiently into high energy particles and gamma-rays. We call this general process magnetoluminescence. Global requirements on the underlying, extreme particle acceleration processes are described and the likely importance of relativistic beaming in enhancing the observed radiation from a flare is emphasized. Recent research on fluid descriptions of unstable electromagnetic configurations are summarized and progress on the associated kinetic simulations that are needed to account for the acceleration and radiation is discussed. Future observational, simulation and experimental opportunities are briefly summarized.Comment: To appear in "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release" of the Space Science Reviews serie

Eating disorders: from twin studies to candidate genes and beyond

Substantial effort has been put into the exploration of the biological background of eating disorders, through family, twin and molecular genetic studies. Family studies have shown that anorexia (AN) and bulimia nervosa (BN) are strongly familial, and that familial etiologic factors appear to be shared by both disorders. Twin studies often focus on broader phenotypes or subthreshold eating disorders. These studies consistently yielded moderate to substantial heritabilities. In addition, there has been a proliferation of molecular genetic studies that focused on Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) AN and BN. Seven linkage regions have been identified in genome-wide screens. Many genetic association studies have been performed, but no consistent association between a candidate gene and AN or BN has been reported. Larger genetic association studies and collaborations are needed to examine the involvement of several candidate genes and biological pathways in eating disorders. In addition, twin studies should be designed to assist the molecular work by further exploring genetic determinants of endophenotypes, evaluating the magnitude of contribution to liability of measured genotypes as well as environmental risk factors related to eating disorders. In this manner twin and molecular studies can move the field forward in a mutually informative way

Fractal Reconnection in Solar and Stellar Environments

Recent space based observations of the Sun revealed that magnetic reconnection is ubiquitous in the solar atmosphere, ranging from small scale reconnection (observed as nanoflares) to large scale one (observed as long duration flares or giant arcades). Often the magnetic reconnection events are associated with mass ejections or jets, which seem to be closely related to multiple plasmoid ejections from fractal current sheet. The bursty radio and hard X-ray emissions from flares also suggest the fractal reconnection and associated particle acceleration. We shall discuss recent observations and theories related to the plasmoid-induced-reconnection and the fractal reconnection in solar flares, and their implication to reconnection physics and particle acceleration. Recent findings of many superflares on solar type stars that has extended the applicability of the fractal reconnection model of solar flares to much a wider parameter space suitable for stellar flares are also discussed.Comment: Invited chapter to appear in "Magnetic Reconnection: Concepts and Applications", Springer-Verlag, W. D. Gonzalez and E. N. Parker, eds. (2016), 33 pages, 18 figure

Disparities in dialysis treatment and outcomes for Dutch and Belgian children with immigrant parents

BACKGROUND: In Belgium and the Netherlands, up to 40% of the children on dialysis are children with immigrant parents of non-Western European origin (non-Western). Concerns exist regarding whether these non-Western patients receive the same quality of care as children with parents of Western European origin (Western). We compared initial dialysis, post-initial treatment, and outcomes between non-Western and Western patients on dialysis. METHODS: All children <19 years old on chronic dialysis in the Netherlands and Belgium between September 2007 and May 2011 were included in the study. Non-Western patients were defined as children of whom one or both parents were born in non-Western countries. RESULTS: Seventy-nine of the 179 included patients (44%) were non-Western children. Compared to Western patients, non-Western patients more often were treated with hemodialysis (HD) instead of peritoneal dialysis (PD) as first dialysis mode (52 vs. 37%, p = 0.046). Before renal transplantation, non-Western patients were on dialysis for a median (range) of 30 (5-99) months, vs. 15 (0-66) months in Western patients (p = 0.007). Renal osteodystrophy was diagnosed in 34% of non-Western vs. 18% of Western patients (p = 0.028). The incidence rate ratio [95% confidence interval] for acute peritonitis was 2.44 [1.43-4.17] (p = 0.032) for non-Western compared to Western patients. CONCLUSIONS: There are important disparities between children on chronic dialysis with parents from Western European origin and those from non-Western European origin in the choice of modality, duration, and outcomes of dialysis therapy

Physics of Solar Prominences: II - Magnetic Structure and Dynamics

Observations and models of solar prominences are reviewed. We focus on non-eruptive prominences, and describe recent progress in four areas of prominence research: (1) magnetic structure deduced from observations and models, (2) the dynamics of prominence plasmas (formation and flows), (3) Magneto-hydrodynamic (MHD) waves in prominences and (4) the formation and large-scale patterns of the filament channels in which prominences are located. Finally, several outstanding issues in prominence research are discussed, along with observations and models required to resolve them.Comment: 75 pages, 31 pictures, review pape

Inducible Transgenic Rat Model for Diabetes Mellitus Based on shRNA-Mediated Gene Knockdown

The rat is an important animal model in biomedical research, but gene targeting technology is not established for this species. Therefore, we aimed to produce transgenic knockdown rats using shRNA technology and pronuclear microinjection. To this purpose, we employed a tetracycline-inducible shRNA expression system targeting the insulin receptor (IR). Doxycycline (DOX) treatment of the resulting transgenic rats led to a dose-dependent and reversible increase in blood glucose caused by ubiquitous inhibition of IR expression and signalling. We could neither detect an interferon response nor disturbances in microRNA processing after DOX treatment excluding toxic effects of shRNA expression. Low dose DOX treatment induced a chronic state of diabetes mellitus. In conclusion, we have developed a technology which allows the specific, inducible, and reversible suppression of any gene of interest in the rat. Our first transgenic rat line generated with this method represents an inducible model for diabetes mellitus