Laboratory simulations of astrophysical jets and solar coronal loops: new results

An experimental program underway at Caltech has produced plasmas where the shape is neither fixed by the vacuum chamber nor fixed by an external coil set, but instead is determined by self-organization. The plasma dynamics is highly reproducible and so can be studied in considerable detail even though the morphology of the plasma is both complex and time-dependent. A surprising result has been the observation that self-collimating MHD-driven plasma jets are ubiquitous and play a fundamental role in the self-organization. The jets can be considered lab-scale simulations of astrophysical jets and in addition are intimately related to solar coronal loops. The jets are driven by the combination of the axial component of the J×B force and the axial pressure gradient resulting from the non-uniform pinch force associated with the flared axial current density. Behavior is consistent with a model showing that collimation results from axial non-uniformity of the jet velocity. In particular, flow stagnation in the jet frame compresses frozen-in azimuthal magnetic flux, squeezes together toroidal magnetic field lines, thereby amplifying the embedded toroidal magnetic field, enhancing the pinch force, and hence causing collimation of the jet

Seasonal variability of the warm Atlantic Water layer in the vicinity of the Greenland shelf break

The warmest water reaching the east and west coast of Greenland is found between 200?m and 600?m. Whilst important for melting Greenland's outlet glaciers, limited winter observations of this layer prohibit determination of its seasonality. To address this, temperature data from Argo profiling floats, a range of sources within the World Ocean Database and unprecedented coverage from marine-mammal borne sensors have been analysed for the period 2002-2011. A significant seasonal range in temperature (~1-2?°C) is found in the warm layer, in contrast to most of the surrounding ocean. The phase of the seasonal cycle exhibits considerable spatial variability, with the warmest water found near the eastern and southwestern shelf-break towards the end of the calendar year. High-resolution ocean model trajectory analysis suggest the timing of the arrival of the year's warmest water is a function of advection time from the subduction site in the Irminger Basin

The Scalar Meson f0(980) in Heavy-Meson Decays

A phenomenological analysis of the scalar meson f0(980) is performed that relies on the quasi-two body decays D and Ds -> f0(980)P, with P=pi, K. The two-body branching ratios are deduced from experimental data on D or Ds -> pi pi pi, K Kbar pi and from the f0(980) -> pi+ pi- and f0(980) -> K+ K- branching fractions. Within a covariant quark model, the scalar form factors F0(q2) for the transitions D and Ds -> f0(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a quark-antiquark state for the scalar and pseudoscalar mesons. They allow to extract information on the f0(980) wave function in terms of u-ubar, d-dbar and s-sbar pairs as well as on the mixing angle between the strange and non-strange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f0(980) structure to evaluate the scalar and vector form factors in the transitions D and Ds -> f0(980), as well as to make predictions for B and Bs -> f0(980), for the entire kinematically allowed momentum range of q2.Comment: 45 pages, 9 figures and 9 tables. The use of dispersion relations to calculate the weak transition form factors is better justified. A more extensive discussion on the strange and non-strange flavor content mixing is introduced. Results unchanged. Version to appear in Phys. Rev.

The Pediatric Sepsis Biomarker Risk Model (PERSEVERE) Biomarkers Predict Clinical Deterioration and Mortality in Immunocompromised Children Evaluated for Infection

Pediatric sepsis and bacterial infection cause significant morbidity and mortality worldwide, with immunocompromised patients being at particularly high risk of rapid deterioration and death. This study evaluated if PERSEVERE, PERSEVERE-II, or the PERSEVERE biomarkers, can reliably estimate the risk of clinical deterioration and 28-day mortality among immunocompromised pediatric patients. This is a single-center prospective cohort study conducted from July 2016 through September 2017 incorporating 400 episodes of suspected bacterial infection from the inpatient units at Cincinnati Children's Hospital Medical Center, a large, tertiary care children's hospital. The primary analysis assessed clinical deterioration within 72 hours of evaluation for infection. Secondarily, we assessed 28-day mortality. Clinical deterioration was seen in 15% of subjects. Twenty-eight day mortality was 5%, but significantly higher among critically ill patients. Neither PERSEVERE nor PERSEVERE-II performed well to predict clinical deterioration or 28-day mortality, thus we derived new stratification models using the PERSEVERE biomarkers with both high sensitivity and negative predictive value. In conclusion, we evaluated previously validated biomarker risk models in a novel population of largely non-critically ill immunocompromised pediatric patients, and attempted to stratify patients based on a new outcome metric, clinical deterioration. The new highly predictive models indicate common physiologic pathways to clinical deterioration or death from bacterial infection

Search for supersymmetry in final states with two or three soft leptons and missing transverse momentum in proton-proton collisions at root s=13 TeV

A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at s&radic; = 13 TeV collected in the three-year period 2016&ndash;2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb&minus;1. The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on &chi;&sim;02/&chi;&sim;&plusmn;1 masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter &mu; up to 180 GeV with the bino mass parameter M1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV.</p

Who are these youths? Language in the service of policy

In the 1990s policy relating to children and young people who offend developed as a result of the interplay of political imperatives and populist demands. The ‘responsibilisation’ of young offenders and the ‘no excuses’ culture of youth justice have been ‘marketed’ through a discourse which evidences linguistic changes. This article focuses on one particular area of policy change, that relating to the prosecutorial decision, to show how particular images of children were both reflected and constructed through a changing selection of words to describe the non-adult suspect and offender. In such minutiae of discourse can be found not only the signifiers of public attitudinal and policy change but also the means by which undesirable policy developments can be challenged

Measurements of the associated production of a W boson and a charm quark in proton-proton collisions at √s=8TeV

Measurements of the associated production of aW boson and a charm (c) quark in proton&ndash;proton collisionsat a centre-of-mass energy of 8 TeV are reported. The anal-ysis uses a data sample corresponding to a total integratedluminosity of 19.7 fb&minus;1 collected by the CMS detector atthe LHC. The W bosons are identified through their leptonicdecays to an electron or a muon, and a neutrino. Charm quarkjets are selected using distinctive signatures of charm hadrondecays. The product of the cross section and branching frac-tion &sigma; (pp &rarr; W + c + X)B(W &rarr; �&nu;), where � = e or &mu;,and the cross section ratio &sigma; (pp &rarr; W+ + &macr;c + X)/&sigma; (pp &rarr;W&minus; + c + X) are measured in a fiducial volume and differ-entially as functions of the pseudorapidity and of the trans-verse momentum of the lepton from the W boson decay. Theresults are compared with theoretical predictions. The impactof these measurements on the determination of the strangequark distribution is assessed.</p

Still policing the crisis?

Writing this has been a troubling experience. Returning to a text 30 years on in this way combines intellectual, political and personal reflections in an unsettling way. These range from a powerful attachment to processes of collective or collaborative intellectual work that Policing the Crisis (PTC; Hall et al., 1978) embodied and enhanced to a rather depressed sense of how many things the book got right about the trajectory of the British social formation in the mid 1970s (other futures might have been preferable). And above all, there is a sense of what the book stands for in the emergence of cultural studies as an institutionalized academic field. As a way of trying to digest these different responses, I have tried to address three sorts of questions: why PTC mattered, where it belongs and why it continues to have echoes in the present

Study of dijet events with large rapidity separation in proton-proton collisions at root s=2.76 TeV

The cross sections for inclusive and Mueller-Navelet dijet production are measured as a function of the rapidity separation between the jets in proton-proton collisions at s&radic; = 2.76 TeV for jets with transverse momentum pT &gt; 35 GeV and rapidity |y| &lt; 4.7. Various dijet production cross section ratios are also measured. A veto on additional jets with pT &gt; 20 GeV is introduced to improve the sensitivity to the effects of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution. The measurement is compared with the predictions of various Monte Carlo models based on leading-order and next-to-leading-order calculations including the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi leading-logarithm (LL) parton shower as well as the LL BFKL resummation.</p