Energy transport in Heisenberg chains beyond the Luttinger liquid paradigm

We study the energy transport between two interacting spin chains which are initially separated, held at different temperatures and subsequently put in contact. We consider the spin-1/2 XXZ model in the gapless regime and exploit its integrability properties to formulate an analytical Ansatz for the non-equilibrium steady state even at temperatures where the low-energy Luttinger liquid description is not accurate. We apply our method to compute the steady energy current and benchmark it both with the known low-energy limit and at higher temperatures with numerical simulations. We find an excellent agreement even at high temperatures, where the Luttinger liquid prediction is shown to fail.Comment: 5 pages + 3 suppl. mat., 5 figure

Stable Torque Optimization for Redundant Robots Using a Short Preview

We consider the known phenomenon of torque oscillations and motion instabilities that occur in redundant robots during the execution of sufficiently long Cartesian trajectories when the joint torque is instantaneously minimized. In the framework of online local redundancy resolution methods, we propose basic variations of the minimum torque scheme to address this issue. Either the joint torque norm is minimized over two successive discrete-time samples using a short preview window, or we minimize the norm of the difference with respect to a desired momentum-damping joint torque, or the two schemes are combined together. The resulting local control methods are all formulated as well-posed linear quadratic problems, and their closed-form solutions also generate low joint velocities while addressing the primary torque optimization objectives. Stable and consistent behaviors are obtained along short or long Cartesian position trajectories, as illustrated with simulations on a 3R planar arm and with experiments on a 7R KUKA LWR robot

Energy transport between two integrable spin chains

We study the energy transport in a system of two half-infinite XXZ chains initially kept separated at different temperatures, and later connected and let free to evolve unitarily. By changing independently the parameters of the two halves, we highlight, through bosonisation and time-dependent matrix-product-state simulations, the different contributions of low-lying bosonic modes and of fermionic quasi-particles to the energy transport. In the simulations we also observe that the energy current reaches a finite value which only slowly decays to zero. The general pictures that emerges is the following. Since integrability is only locally broken in this model, a pre-equilibration behaviour may appear. In particular, when the sound velocities of the bosonic modes of the two halves match, the low-temperature energy current is almost stationary and described by a formula with a non-universal prefactor interpreted as a transmission coefficient. Thermalisation, characterized by the absence of any energy flow, occurs only on longer time-scales which are not accessible with our numerics.Comment: 15 pages, 14 figure

Velocity-gradient probability distribution functions in a lagrangian model of turbulence

The Recent Fluid Deformation Closure (RFDC) model of lagrangian turbulence is recast in path-integral language within the framework of the Martin–Siggia–Rose functional formalism. In order to derive analytical expressions for the velocity-gradient probability distribution functions (vgPDFs), we carry out noise renormalization in the low-frequency regime and find approximate extrema for the Martin–Siggia–Rose effective action. We verify, with the help of Monte Carlo simulations, that the vgPDFs so obtained yield a close description of the single-point statistical features implied by the original RFDC stochastic differential equations.Indisponível

Energy transport in an integrable parafermionic chain via generalized hydrodynamics

We study energy transport in the integrable Z3 parafermionic chain using the partitioning protocol. By exploiting the Bethe-ansatz solution for the thermodynamics of the system, we develop a generalized hydrodynamic description of the nonequilibrium steady states, which we benchmark using numerical simulations based on matrix product states. The model features a low-energy conformal limit with central charge c=45, which affects the low-temperature energy current, as we explicitly show. Moreover, we exploit that, for energies close to the maximally excited state, the system is also critical and described by a conformal field theory with c=1. By considering the two halves prepared at two temperatures both low in value but opposite in sign, we are able to investigate in an exact and controlled way the junction between two conformal field theories with different central charges. Notwithstanding the absence of global conformal invariance, we find results that approximate to a high degree those of out-of-equilibrium conformal field theories. Our study extends the generalized hydrodynamics to a framework where it can be profitably used for exploring new physical phenomena

Self-efficacy for coping. Utility of the Cancer behavior inventory (Italian) for use in palliative care

Background: Newer models of palliative and supportive cancer care view the person as an active agent in managing physical and psychosocial challenges. Therefore, personal efficacy is an integral part of this model. Due to the lack of instruments in Italian to assess coping self-efficacy, the present study included the translation and validation of the Italian version of the Cancer Behavior Inventory-Brief (CBI-B/I) and an initial analysis of the utility of self-efficacy for coping in an Italian sample of palliative care patients. Methods: 216 advanced cancer patients who attended palliative care clinics were enrolled. The CBI-B/I was administered along with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), the Mini Mental Adjustment to Cancer Scale (Mini-MAC), the Cancer Concerns Checklist (CCL), and the Hospital Anxiety and Depression Scale (HADS). The Eastern Cooperative Oncology Group Performance Status (ECOG-PS) ratings of functional capacity were completed by physicians. Results: Factor analysis confirmed that the structure of the CBI-B/I was consistent with the English version. Internal consistency reliability and significant correlations with the EORTC QLQ-C30, Mini-MAC, and HADS supported the concurrent validity of the CBI-B/I. Differences in CBI-B/I scores for high versus low levels of the CCL and ECOG-PS supported the clinical utility of the CBI-B/I. Conclusions: The CBI-B/I has strong psychometric properties and represents an important addition to newer model of palliative and supportive care. In order to improve clinical practice, the CBI-B/I could be useful in identifying specific self-efficacy goals for coping in structured psychosocial intervention

Evaluation of the effects of cyclododecane on oil paintings

The solubility of oil paint components during the application of cyclododecane in solvent mixtures was evaluated in order to predict if the application of cyclododecane during restoration may significantly alter the chemical state of the paint layer in oil paintings. The chemical affinity between some of the oil binder components and non-polar cyclododecane could potentially lead to interactions or leaching during the application. In order to investigate these effects a set of samples taken from oil paintings from the early 1900s and 2008, were treated with cyclododecane in a solution, melted, and sprayed as aerosol. The samples were also submitted to a comparative extractive treatment with cyclododecane and organic solvents of different polarities. After the treatments, the extracted components were analysed by gas chromatography-mass spectrometry (GC/MS), which provided detailed molecular information on the composition of the extracts, together with a quantitative profile of fatty acids in extracted triglycerides, after saponification and derivatisation. The results show that applications of cyclododecane both as a spray and in a saturated solution in a hydrocarbon solvent determine the extraction of a low amount of lipids from the paint. On the other hand, when cyclododecane is applied in the melted form, there is an extraction of lipid components of the paint into the treatment solution

Intensive Care Unit Acquired Weakness (ICU-AW): a brief and practical review

Intensive care unit-acquired weakness (ICU-AW) is an increasingly complication of survivors of critical illness. It should be suspected in the presence of  a patient with a flaccid  tetraparesis or tetraplegia with hyporeflexia or absent deep tendon reflexes and difficult to weaning from mechanical ventilation in the absence of different diagnoses. Important risk factors are age, sepsis, illness duration and severity, some drugs (neuromuscular blockers, steroids). Electrophysiological studies have shown an axonal damage of involved peripheral nerves (critical illness polyneuropathy). However, muscle can also be primitively affected (critical illness myopathy) leading to ICUAW with inconstant myopathic damage patterns in electromyographic studies. Mixed forms can are present (critical illness polyneuromyopathy. Although the pathophysiology remains obscure, the hypothesis of an acquired channelopathy is substantial.Electroneuromyography is crucial for diagnosis. Muscular and nerve biopsy are necessary for diagnosis confirmation. Aggressive treatment of baseline disease, prevention, through avoiding or minimizing precipitating factors, strict glycemic control, and early rehabilitation combining mobilization with physiotherapy and muscle electrical muscle stimulation, are the keys to improving recovery of the affected individuals. This narrative review highlights the current literature regarding the etiology and diagnosis of ICU-AW

Lightweight and Effective Convolutional Neural Networks for Vehicle Viewpoint Estimation From Monocular Images

Vehicle viewpoint estimation from monocular images is a crucial component for autonomous driving vehicles and for fleet management applications. In this paper, we make several contributions to advance the state-of-the-art on this problem. We show the effectiveness of applying a smoothing filter to the output neurons of a Convolutional Neural Network (CNN) when estimating vehicle viewpoint. We point out the overlooked fact that, under the same viewpoint, the appearance of a vehicle is strongly influenced by its position in the image plane, which renders viewpoint estimation from appearance an ill-posed problem. We show how, by inserting in the model a CoordConv layer to provide the coordinates of the vehicle, we are able to solve such ambiguity and greatly increase performance. Finally, we introduce a new data augmentation technique that improves viewpoint estimation on vehicles that are closer to the camera or partially occluded. All these improvements let a lightweight CNN reach optimal results while keeping inference time low. An extensive evaluation on a viewpoint estimation benchmark and on actual vehicle camera data shows that our method significantly outperforms the state-of-the-art in vehicle viewpoint estimation, both in terms of accuracy and memory footprint