Current Status of Simulations

As the title suggests, the purpose of this chapter is to review the current status of numerical simulations of black hole accretion disks. This chapter focuses exclusively on global simulations of the accretion process within a few tens of gravitational radii of the black hole. Most of the simulations discussed are performed using general relativistic magnetohydrodynamic (MHD) schemes, although some mention is made of Newtonian radiation MHD simulations and smoothed particle hydrodynamics. The goal is to convey some of the exciting work that has been going on in the past few years and provide some speculation on future directions.Comment: 15 pages, 14 figures, to appear in the proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 October 2012

Deaths due to differentiated thyroid cancer: A 46-year perspective

From 1940 to 1986, a total of 798 patients were treated for differentiated thyroid carcinoma. One hundred and seventy-two patients died during the follow-up period: 42 (24.4%) patients from thyroid cancer, 14 (8.1%) from other causes with extensive thyroid cancer present, 75 (43.6%) with no thyroid cancer, and 41 (23.8%) with an unknown status of thyroid cancer . Of the 42 patients dying due to thyroid cancer, 15 were male and 27, female. Mean age at diagnosis was 48.3±17.7 years with one-third of patients age 45 or younger at the time of the initial diagnosis. The primary tumors were large (>4 cm) and 59.5% of the patients had local invasion and/or cervical metastasis. Distant metastases were present in 9 (21.4%) patients at the time of diagnosis . Surgical therapy included total thyroidectomy (72.1%) and limited or radical neck dissection (69.4%). Radioactive iodine ( 131 I) was used to treat residual cancer and/or distant metastasis in 73.8% of the patients. External radiation therapy was used to treat locally advanced or recurrent disease in 52.3% of the patients. Distant metastases and local recurrence were identified earlier in patients with follicular thyroid cancer whose survival time and disease-free interval were significantly shorter ( p < 0.001) than that of patients with papillary neoplasms. However, the survival and disease-free intervals were often very long in both papillary and follicular thyroid cancer deaths . Onset of differentiated thyroid cancer before the age of 40 years does not preclude serious sequelae and death. Since no known histopathologic features can consistently predict outcome, we continue to advocate aggressive treatment of all patients with differentiated thyroid cancer . Entre 1940 et 1986, 798 patients au total ont été traités pour un cancer différencié de la thyroïde. Cent-soixant-douze patients sont morts par la suite: 42 (24.4%) de leur cancer, 14 (8.1%) d'une autre cause alors que des signes d'extension du cancer étaient présents, 75 (43.6%) d'une autre cause sans signe de cancer, et 41 (23.8%) sans qu'on ait pu connaître le stade du cancer. Des 42 patients morts de leur cancer, il y avait 15 hommes et 27 femmes. L'âge moyen au moment du diagnostic était de 48.3±17.7 ans: un tiers des patients avait 45 ans ou moins au moment du diagnostic. Les tumeurs primitives avaient plus de 4 cm et 59.5% des patients présentaient un envahissement local et/ou une métastase cervicale. Les métastases à distance ont été détectées chez 9 (21.4%) patients au moment du diagnostic. Une thyroïdectomie totale a été effectuée chez 72.1% des patients, associée à un curage cervical limité ou radical chez 69.4% des patients. Chez 73.8% des patients on a traité le tissu cancéreux résiduel et/ou des métastases à distance par de l'I 131. La radiothérapie a été utilisée pour traiter les patients présentant une extension importante ou une récidive chez 52.3% des patients. Des métastases à distance et des récidives ont été identifiées précocement chez les patients ayant un cancer folliculaire. Dans ce groupe de patients, la survie et l'intervalle de temps sans maladie étaient significativement plus courts ( p <0.001) que chez les patients ayant un cancer papillaire. Il faut cependant noter que la survie et l'intervalle de temps sans maladie étaient très longs dans les 2 groupes de patients. La découverte d'un cancer différencié de la thyroïde avant l'âge de 40 ans n'est pas un facteur pronostique particulier. Puisqu'il n'y pas de facteur histologique permettant de prévoir l'évolution, nous continuons de préconiser un traitement agressif chez tout patient présentant un cancer différencié de la thyroïde. En el período 1940–1986, un total de 798 pacientes recibieron tratamiento para carcinoma tiroideo; 172 murieron en el curso del seguimiento: 42 (24.4%) por cancer tiroideo, 14 (8.1%) por otras causas pero con presencia de extenso cáncer tiroideo, 75 (43.6%) libres de cáncer tiroideo, y 41 (23.8%) con estado desconocido en cuanto al cancer tiroideo.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41283/1/268_2005_Article_BF01655866.pd

Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo

GLE1 mutations cause lethal congenital contracture syndrome 1 (LCCS1), a severe autosomal recessive fetal motor neuron disease, and more recently have been associated with amyotrophic lateral sclerosis (ALS). The gene encodes a highly conserved protein with an essential role in mRNA export. The mechanism linking Gle1 function to motor neuron degeneration in humans has not been elucidated, but increasing evidence implicates abnormal RNA processing as a key event in the pathogenesis of several motor neuron diseases. Homozygous gle1−/− mutant zebrafish display various aspects of LCCS, showing severe developmental abnormalities including motor neuron arborization defects and embryonic lethality. A previous gene expression study on spinal cord from LCCS fetuses indicated that oligodendrocyte dysfunction may be an important factor in LCCS. We therefore set out to investigate the development of myelinating glia in gle1−/− mutant zebrafish embryos. While expression of myelin basic protein (mbp) in hindbrain oligodendrocytes appeared relatively normal, our studies revealed a prominent defect in Schwann cell precursor proliferation and differentiation in the posterior lateral line nerve. Other genes mutated in LCCS have important roles in Schwann cell development, thereby suggesting that Schwann cell deficits may be a common factor in LCCS pathogenesis. These findings illustrate the potential importance of glial cells such as myelinating Schwann cells in motor neuron diseases linked to RNA processing defects

General Overview of Black Hole Accretion Theory

I provide a broad overview of the basic theoretical paradigms of black hole accretion flows. Models that make contact with observations continue to be mostly based on the four decade old alpha stress prescription of Shakura & Sunyaev (1973), and I discuss the properties of both radiatively efficient and inefficient models, including their local properties, their expected stability to secular perturbations, and how they might be tied together in global flow geometries. The alpha stress is a prescription for turbulence, for which the only existing plausible candidate is that which develops from the magnetorotational instability (MRI). I therefore also review what is currently known about the local properties of such turbulence, and the physical issues that have been elucidated and that remain uncertain that are relevant for the various alpha-based black hole accretion flow models.Comment: To be published in Space Science Reviews and as hard cover in the Space Sciences Series of ISSI: The Physics of Accretion on to Black Holes (Springer Publisher

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo