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Energy-loss studies of hard particle probes produced in heavy-ion collisions have often been used to get information on the interactions within the medium of a quark-gluon plasma (QGP). However, with the study of in-medium energy-loss of individual particles alone, it remains still ambiguous, whether the occurred decrease in particle energy is caused by predominantly radiative or collisional energy-loss mechanisms. Focusing on the in-medium energy-loss of hard jet partons, we propose additional studies of the angular jet structure as a means to further constrain the energy-loss mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: We present a model for radiative energy loss of heavy quarks in quark gluon plasma which incorporates coherence effects. We then study its consequences on the radiation spectra as well as on the nuclear modification factor of open heavy mesons produced in ultrarelativistic heavy ion collisions. [Copyright &y& Elsevier]

This paper reports the first results from a program of work aimed at developing a swimming robot equipped with electric sense. After having presented the principles of a bioinspired electric sensor that is now working, we will build the models for electrolocation of objects that are suited to this kind of sensor. The produced models are in a compact analytical form in order to be tractable on the onboard computers of the future robot. These models are tested by comparing them with numerical simulations based on the boundary elements method. The results demonstrate the feasibility of the approach and its compatibility with online objects electrolocation, i.e., another parallel program of ours. [ABSTRACT FROM PUBLISHER]

Abstract: A promising probe to study deconfined matter created in high energy nuclear collisions is the energy loss of (heavy) quarks. Experiments at the Relativistic Heavy Ion Collider (RHIC) have shown that heavy quarks, i.e. charm and bottom quarks show a remarkable high momentum suppression, comparable to light quarks. In this exploratory study we investigate the energy loss of heavy quarks in high multiplicity proton proton collisions at LHC energies. We will find a small, however non-negligible energy loss of high momentum charm quarks. [Copyright &y& Elsevier]

This article describes an active learning method for the teaching of physical sciences and mathematics to engineers. After defining the challenges involved in the training of engineers, we shall describe the answers provided by our method, 'learning by doing' (named 'Apprentissage Par l'Action' in French), by introducing four key points: real-life simulation, the management of non-success, the result requirement and the different roles of the teachers. An assessment of this experience is carried out which emphasizes the factors paramount in the success of this pedagogical innovation. Similarities between our experience and other well-known methods such as problem-based learning, problem solving and, more generally, the concept of learning by doing coined by John Dewey in his philosophy of education, are mentioned. [ABSTRACT FROM AUTHOR]

Objective: To assess the morbidity and its main risk factors after major hepatic resection. Design: Retrospective study of prospectively collected data. Setting: University hospital, France. Subjects: 100 consecutive patients who underwent major hepatic resections, 1989-95. Interventions: Major hepatic resection, defined as resection involving 3 or more segments according to Couinaud's classification, in all cases. Main outcome measures: All complications that affected outcome or prolonged hospital stay. Risk factors identified by univariate and multivariate analysis. Results: 45 patients developed at least 1 complication and 7 died. The most common complications were: pleural effusion (n = 21), hepatic failure (n = 12), and ascites (n = 9). Univariate analysis showed that the following variables were significantly related to the morbidity: age >55 years, American Society of Anesthesiologists (ASA) grade II or more, bilirubin >80 μmol/L, alkaline phosphatase activity more than double the reference range, malignant tumours, abnormal liver parenchyma, simultaneous surgical procedures, operative time >4 hours, and perioperative blood transfusion ≥600 ml. The extent of resection did not correlate with postoperative complications. Multivariate analysis showed that volume of blood transfusion ≥600 ml and simultaneous surgical procedures were the most important independent risk factors for complicated outcome. Conclusions: The morbidity associated with major hepatic resections remains high, and the main determinants of outcome are intraoperative surgeon-related factors. [ABSTRACT FROM AUTHOR]

Master equations of the Lindblad type have recently been derived to describe the dynamics of quarkonium states in the quark–gluon plasma. Because their full resolution in three dimensions is very challenging, the equations are often reduced to one dimension. The main ingredient of these equations is the complex potential that describes the binding of the heavy quark-antiquark pairs and their interactions with the medium. In this work, we propose a one-dimensional complex potential parameterized to reproduce at best two key properties – the temperature-dependent masses of the eigenstates and their decay widths – of a three-dimensional lattice QCD inspired potential. Their spectral decompositions are calculated to check their compatibility with the positivity of the master equations. [ABSTRACT FROM AUTHOR]

We present numerical solutions in a one-dimensional setting of quantum master equations that have been recently derived. We focus on the dynamics of a single heavy quark-antiquark pair in a Quark-Gluon Plasma in thermal equilibrium, in the so-called quantum Brownian regime where the temperature of the plasma is large in comparison with the spacing between the energy levels of the Q Q ¯ system. The one-dimensional potential used in the calculations has been adjusted so as to produce numbers that are relevant for the phenomenology of the charmonium. The equations are solved using different initial states and medium configurations. Various temperature regimes are studied and the effects of screening and collisions thoroughly analyzed. Technical features of the equations are analyzed. The contributions of the different operators that control the evolution are discussed as a function of the temperature. Some phenomenological consequences are addressed. [ABSTRACT FROM AUTHOR]

The suppression of D mesons in non-central heavy-ion collisions is investigated. The anisotropy in collisions at finite impact parameter leads to an ordering of all-angle, in- and out-of-plane nuclear modification factors due to the different in-medium path lengths. Within our MC@sHQ+EPOS model of heavy-quark propagation in the QGP we demonstrate that fluctuating initial conditions lead to an effective reduction of the energy loss of heavy quarks, which is seen in a larger nuclear modification factor at intermediate and high transverse momenta. The elliptic flow at small transverse momenta is reduced. [ABSTRACT FROM AUTHOR]

In this paper we study the azimuthal correlations of heavy quarks in Pb + Pb collisions with √s = 2.76 TeV at the Large Hadron Collider. Due to the interaction with the medium, heavy quarks and antiquarks are deflected from their original direction and the initial correlation of the pair is broadened. We investigate this effect for different transverse momentum classes. Low-momentum heavy-quark pairs lose their leading-order back-to-back initial correlation, while a significant residual correlation survives at large momenta. Due to the larger acquired average deflection from their original directions the azimuthal correlations of heavy-quark pairs are broadened more efficiently in a purely collisional energy loss mechanism compared to that including radiative corrections. This discriminatory feature survives when next-to-leading-order production processes are included. [ABSTRACT FROM AUTHOR]

We investigate how the possible existence of hadronic bound states above the deconfinement transition temperature Tc affects heavy-quark observables, such as the nuclear modification factor, the elliptic flow, and azimuthal correlations. Lattice QCD calculations suggest that above Tc the effective degrees of freedom might not be exclusively partonic but that a certain fraction of hadronic degrees of freedom might already form at higher temperatures. This is an interesting question by itself but also has a strong influence on other probes of the strongly interacting matter produced in ultrarelativistic heavy-ion collisions. A substantial fraction of hadronic bound states above Tc reduces on average the interaction of the heavy quarks with colored constituents of the medium. We find that all studied observables are highly sensitive to the active degrees of freedom in the quark-gluon plasma. [ABSTRACT FROM AUTHOR]

Heavy-quark observables in ultrarelativistic heavy-ion collisions, like the nuclear modification factor and the elliptic flow, give insight into the mechanisms of high-momentum suppression and low-momentum thermalization of heavy quarks. Here, we present a global study of these two observables within a coupled approach of the heavy-quark propagation in a realistic fluid dynamical medium, MC@sHQ+EPOS2, and compare with experimental data from the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider experiments. The heavy quarks scatter elastically and inelastically with the quasiparticles of the quark-gluon plasma (QGP), which are represented consistently with the underlying equation of state. We examine two scenarios: first, we interpret the lattice QCD equation of state as a sum of partonic and hadronic contributions and, second, as a gas of massive partonic quasiparticles. It is observed that, independent of their momentum, the energy loss of heavy quarks depends strongly on how the lattice QCD equation of state is translated into degrees of freedom of the QGP. [ABSTRACT FROM AUTHOR]

Background & Aims Transarterial chemoembolization (TACE) is the standard of care for intermediate stage hepatocellular carcinoma (HCC) and it is the most commonly used treatment for HCC worldwide. However, no prognostic indices, designed to select appropriate candidates for repeat conventional TACE, have been incorporated in the guidelines. Methods From January 2007 to April 2012, 139 consecutive HCC patients, mainly with an alcohol- or viral-induced disease, were treated with TACE. Using a regression model on the prognostic variables of our population, we determined a score designed to help for repeat TACE and we validated it in two cohorts. We also compared it to the ART score. Results In the multivariate analysis, four prognostic factors were associated with overall survival: BCLC and AFP (>200 ng/ml) at baseline, increase in Child-Pugh score by ⩾2 from baseline, and absence of radiological response. These factors were included in a score (ABCR, ranging from −3 to +6), which correlates with survival and identifies three groups. The ABCR score was validated in two different cohorts of 178 patients and proofed to perform better than the ART score in distinguishing between patients’ prognosis. Conclusions The ABCR score is a simple and clinically relevant index, summing four prognostic variables endorsed in HCC. An ABCR score ⩾4 prior to the second TACE identifies patients with dismal prognosis who may not benefit from further TACE sessions. [ABSTRACT FROM AUTHOR]

We investigate the elliptic and the triangular (low of heavy mesons in ultrarelativistic heavy-ion collisions at the BNL Relativistic Heavy-Ion Collider and the CERN Large Hadron Collider (LHC). The dynamics of heavy quarks is coupled to the locally thermalized and fluid dynamically evolving quark-gluon plasma. The elliptic flow of D mesons and the centrality dependence measured at the LHC is well reproduced for purely collisional and bremsstrahlung interactions. Due to the event-by-event fluctuating initial conditions from the EPOS2 model, the D meson triangular flow is predicted to be nonzero at √s = 200 GeV and √s = 2.76 TeV. We study the centrality dependence and quantify the contributions stemming from flow of the light bulk event and the hadronization process. The flow coefficients as responses to the initial eccentricities behave differently for heavy mesons than for light hadrons due to their inertia. Higher-order flow coefficients of heavy flavor become important in order to quantify the degree of thermalization. [ABSTRACT FROM AUTHOR]

Electric fish sense the perturbations of a self-generated electric field through their electro-receptive skin. This sense allows them to navigate and reconstruct their environment in conditions where vision and sonar cannot work. In this article, we use a sensor inspired by this sense to address both problems of locating and estimating the size of small objects (electrolocation) and navigating in a tank. Based on a Kalman filter, any small object in the surroundings of the motion-controlled sensor can be modeled as an equivalent sphere whose location is well estimated by the filter. As a first application to the problem of navigation, the filter is included into a closed feedback loop in order to achieve wall following in a tank. Our experimental results demonstrate the feasibility of this approach. [ABSTRACT FROM AUTHOR]

Prospects for quarkonium-production studies accessible during the upcoming high-luminosity phases of the CERN Large Hadron Collider operation after 2021 are reviewed. Current experimental and theoretical open issues in the field are assessed together with the potential for future studies in quarkonium-related physics. This will be possible through the exploitation of the huge data samples to be collected in proton–proton, proton–nucleus and nucleus–nucleus collisions, both in the collider and fixed-target modes. Such investigations include, among others, those of: (i) J / ψ and Υ produced in association with other hard particles; (ii) χ c , b and η c , b down to small transverse momenta; (iii) the constraints brought in by quarkonia on gluon PDFs, nuclear PDFs, TMDs, GPDs and GTMDs, as well as on the low- x parton dynamics; (iv) the gluon Sivers effect in polarised-nucleon collisions; (v) the properties of the quark–gluon plasma produced in ultra-relativistic heavy-ion collisions and of collective partonic effects in general; and (vi) double and triple parton scatterings. [ABSTRACT FROM AUTHOR]

Several transport models have been employed in recent years to analyze heavy-flavor meson spectra in high-energy heavy-ion collisions. Heavy-quark transport coefficients extracted from these models with their default parameters vary, however, by up to a factor of 5 at high momenta. To investigate the origin of this large theoretical uncertainty, a systematic comparison of heavy-quark transport coefficients is carried out between various transport models. Within a common scheme devised for the nuclear modification factor of charm quarks in a brick medium of a quark-gluon plasma, the systematic uncertainty of the extracted drag coefficient among these models is shown to be reduced to a factor of 2, which can be viewed as the smallest intrinsic systematical error band achievable at present time. This indicates the importance of a realistic hydrodynamic evolution constrained by bulk hadron spectra and of heavy-quark hadronization for understanding the final heavy-flavor hadron spectra and extracting heavy-quark drag coefficient. The transverse transport coefficient is less constrained due to the influence of the underlying mechanism for heavy-quark medium interaction. Additional constraints on transport models such as energy loss fluctuation and transverse-momentum broadening can further reduce theoretical uncertainties in the extracted transport coefficients. [ABSTRACT FROM AUTHOR]