Gyrokinetic analysis of radial dependence and global effects on the zero particle flux condition in a TCV plasma

In small-sized tokamaks, finite Larmor radius effects could lead to a significant discrepancy between gyrokinetic local flux-tube results and global ones. This has been highlighted by previous turbulent transport studies as in McMillan et al (2010 Phys. Rev. Lett.). The impact of such effects on the zero particle flux condition is investigated here. The zero particle flux condition is useful to estimate the density peaking, reducing the uncertainty on physical input parameters derived from experimental measurements, for cases where the particle source is negligible. This constraint has been applied to the analysis of a particular TCV discharge, where a detailed reconstruction of the zero particle flux hyper-surface in the multidimensional physical parameter space at fixed radius had been presented in Mariani et al (2018 Phys. Plasmas). Here, we extend these results, investigating their radial dependence, together with the impact of global effects. These so-called rho* effects are analyzed by simulating a plasma annulus corresponding to the stiff region 0.4 <rho(tor)< 0.8. Because of the computational cost of the nonlinear global gyrokinetic simulations, we restrict to a two species plasma in the collisionless regime, with heavy electrons and simplified density and temperature radial profiles. With these simplifications, the results seem to point towards global effects on the zero particle flux condition being relatively weak

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

Enforced Expression of the Transcriptional Coactivator OBF1 Impairs B Cell Differentiation at the Earliest Stage of Development

OBF1, also known as Bob.1 or OCA-B, is a B lymphocyte-specific transcription factor which coactivates Oct1 and Oct2 on B cell specific promoters. So far, the function of OBF1 has been mainly identified in late stage B cell populations. The central defect of OBF1 deficient mice is a severely reduced immune response to T cell-dependent antigens and a lack of germinal center formation in the spleen. Relatively little is known about a potential function of OBF1 in developing B cells. Here we have generated transgenic mice overexpressing OBF1 in B cells under the control of the immunoglobulin heavy chain promoter and enhancer. Surprisingly, these mice have greatly reduced numbers of follicular B cells in the periphery and have a compromised immune response. Furthermore, B cell differentiation is impaired at an early stage in the bone marrow: a first block is observed during B cell commitment and a second differentiation block is seen at the large preB2 cell stage. The cells that succeed to escape the block and to differentiate into mature B cells have post-translationally downregulated the expression of transgene, indicating that expression of OBF1 beyond the normal level early in B cell development is deleterious. Transcriptome analysis identified genes deregulated in these mice and Id2 and Id3, two known negative regulators of B cell differentiation, were found to be upregulated in the EPLM and preB cells of the transgenic mice. Furthermore, the Id2 and Id3 promoters contain octamer-like sites, to which OBF1 can bind. These results provide evidence that tight regulation of OBF1 expression in early B cells is essential to allow efficient B lymphocyte differentiation

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p&lt;0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (&lt;1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (&lt;1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

Successional changes of phytodiversity on a short rotation coppice plantation in Oberschwaben, Germany

To allow for information on successional changes in phytodiversity over time and space, as well as information on differences between clones and treatments, phytodiversity was monitored on a poplar short rotation coppice plantation in Oberschwaben, Southwest Germany, in four consecutive years. The investigated plantation was divided into two core areas, one planted with poplar clone Max4, the other with Monviso; each core area was divided into two blocks with alternating treatments: i) irrigation and fertilization; ii) irrigation; and iii) no treatment. All vascular plant species of the ground vegetation were recorded in 72 permanent sampling plots of 25 m² each during vegetation periods using the Braun-Blanquet scale.Results showed that total number of species increased in first two years and declined after harvest of the SRC-trees. Total vegetation cover decreased during the four years of study. Especially for the two clones there was an opposed trend: grass layer had a high cover on Monviso plots, but low cover on Max4 plots; herb layer the very reverse. However, there was no significant difference between the three treatments compared within each year. Perennial species were dominating over all years, as well as light-demanding species, but their proportion decreased steadily. Our results confirm the conclusion of previous studies which indicate that plant community succession takes place in ground vegetation of SRC and imply that species composition is age-dependent. The selection of clones for SRC can influence ground vegetation; some floristic changes for example caused by different treatments may be visible only when monitored over a longer period of time

Effects of collisionality and T e /T i on fluctuations in positive and negative δ tokamak plasmas

The effects of negative triangularity () on confinement and fluctuations in plasmas covering a large range of parameters were investigated on the tokamak à configuration variable (TCV). The conditions explored in this paper include discharges where neutral beam (NB) heating was employed to obtain an electron-ion temperature ratio across a large fraction of the plasma profile. This significantly extended the range of negative plasmas studied on TCV towards conditions more relevant to future reactor-like tokamaks. Negative triangularity was found to improve confinement over the full range of collisionality studied () and (). The amplitude of radiative temperature fluctuations, measured using a correlation electron cyclotron emission diagnostic over the range , was found to be reduced, in negative with respect to positive plasmas, for all combinations of parameters explored. This was, in particular, verified for a pair of positive and negative plasmas with comparable density and under different conditions of NB heating. Linear gyrokinetic simulations found the dominant turbulence regime, in the strongly NB heated discharges, to be a mixture of trapped electron modes (TEMs) and ion temperature gradient driven modes. This is in contrast to ohmic or electron cyclotron heated discharges, for which the dominant turbulence regime was found to be pure TEM. Negative triangularity was found to lead to partial stabilization of the most unstable modes for low wavenumbers in both turbulence regimes. These findings demonstrate that negative triangularity could provide significant confinement improvement over a large range of parameters, that include conditions closer to future reactor-like machines (, low collisionality)

Gemeinsam mit den Frauen - neue Wege in der Forschung

UuStB Koeln(38)-19A7249 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

On the non-stiffness of edge transport in L-modes

Transport analyses using first principle turbulence codes as well as 1½-D transport codes often study transport properties between the plasma axis and a normalized radius around 0.8. In this region, heat transport shows significant stiffness properties leading to R/LTe values that are relatively independent of auxiliary input power. In this work, we study experimentally in the TCV tokamak, the transport properties of the edge region, close to the last closed flux surface, namely between ρV=0.8 and 1 (ρψ≥0.9). It is shown that electron transport is not stiff in this region and extremely high R/LTe values can be attained even for L-mode confinement. These results bring a new perspective to several "accepted" understandings. In particular a specific study related to the Ip scaling of ohmic and ECH L-mode discharges shows that the strong Ip scaling is in fact related in a large part to this non-stiff edge region. The Te scale length is shown to be proportional to Ip in the edge region and constant (independent of Ip) in the core region. The relation with L-H transition and the I-modes will also be discussed, since it shows that the edge gradient can be continuously increased, by increasing the input power, even in the L-mode phase. It is also proposed that the pedestal width is related to the width over which the transport is non-stiff, and can be studied in detail already in L-mode. The present study also explains the large improved confinemet obtain with negative triangularity and a new model is proposed including non-stiff edge local transport which can recover the experimental observations. This work was supported in part by the Swiss National Science Foundation

Integration of the state observer RAPTOR in the real-time MARTe framework at RFX-mod

The RAPTOR - RApid Plasma Transport simulatOR code is a model-based control-oriented code that predicts Tokamak plasma profile evolution in real-time. One of its key applications is in a state observer, where the real-time predictions are combined with the measurements of the available diagnostics, yielding a complete estimate of the plasma profiles. The state observer RAPTOR is currently installed in the real-time control system of TCV, where it has been originally developed, ASDEX-Upgrade and recently RFX-mod. The latter has pioneered its integration in the real-time MARTe - Multi-threaded Application Real-Time executor framework, which will be the topic of this work. Thanks to this, RFX-mod can now contribute to develop integrated control techniques based on the state observer RAPTOR to avoid disruptions, which are highly reproducible in q(a) <2 RFX-mod Tokamak plasmas if they are left uncontrolled