Tel Aviv University

About: Tel Aviv University is a education organization based out in Tel Aviv, Israel. It is known for research contribution in the topics: Population & Medicine. The organization has 47791 authors who have published 115959 publications receiving 3904391 citations. The organization is also known as: TAU & Universiṭat Tel-Aviv.

Risk Sharing and Industrial Specialization: Regional and International Evidence

Abstract: We provide empirical evidence that risk sharing enhances specialization in production. First, we calculate an index of specialization for each of the European Community (EC) and non-EC OECD countries, U.S. states, Canadian provinces, Japanese prefectures, Latin American countries, and regions of Italy, Spain, and the United Kingdom. Then, we estimate the degree of capital market integration (risk sharing) within each of these groups of regions. Finally, we perform a regression of the specialization index on the degree of risk sharing, controlling for relevant economic variables and find a positive relation between the degree of specialization and the amount of risk sharing within a group. Instrumental variables regressions confirm that risk sharing is a causal determinant of specialization.

A myosignal-based powered exoskeleton system

Abstract: This paper studies the integration of a human arm with a powered exoskeleton (orthotic device) and its experimental implementation in an elbow joint, naturally controlled by the human. The human-machine interface was set at the neuromuscular level, by using the neuromuscular signal (EMG) as the primary command signal for the exoskeleton system. The EMG signal along with the joint kinematics were fed into a myoprocessor which in turn predicted the muscle moments on the elbow joint. The moment-based control system integrated myoprocessor moment prediction with feedback moments measured at the human arm/exoskeleton and external load/exoskeleton interfaces. The exoskeleton structure under study was a two-link, two-joint mechanism, corresponding to the arm limbs and joints, which was mechanically linked by the human operator. Four indices of performance were used to define the quality of the human/machine integration and to evaluate the operational envelope of the system. Experimental results indicate the feasibility of an EMG-based power exoskeleton system as an integrated human-machine system using high-level neurological signals.

Superluminal motion of a relativistic jet in the neutron-star merger GW170817

Abstract: The binary neutron-star merger GW1708171 was accompanied by radiation across the electromagnetic spectrum2 and localized2 to the galaxy NGC 4993 at a distance3 of about 41 megaparsecs from Earth. The radio and X-ray afterglows of GW170817 exhibited delayed onset4–7, a gradual increase8 in the emission with time (proportional to t0.8) to a peak about 150 days after the merger event9, followed by a relatively rapid decline9,10. So far, various models have been proposed to explain the afterglow emission, including a choked-jet cocoon4,8,11–13 and a successful-jet cocoon4,8,11–18 (also called a structured jet). However, the observational data have remained inconclusive10,15,19,20 as to whether GW170817 launched a successful relativistic jet. Here we report radio observations using very long-baseline interferometry. We find that the compact radio source associated with GW170817 exhibits superluminal apparent motion between 75 days and 230 days after the merger event. This measurement breaks the degeneracy between the choked- and successful-jet cocoon models and indicates that, although the early-time radio emission was powered by a wide-angle outflow8 (a cocoon), the late-time emission was most probably dominated by an energetic and narrowly collimated jet (with an opening angle of less than five degrees) and observed from a viewing angle of about 20 degrees. The imaging of a collimated relativistic outflow emerging from GW170817 adds substantial weight to the evidence linking binary neutron-star mergers and short γ-ray bursts.

A survey of visibility for walkthrough applications

Abstract: Visibility algorithms for walkthrough and related applications have grown into a significant area, spurred by the growth in the complexity of models and the need for highly interactive ways of navigating them. In this survey, we review the fundamental issues in visibility and conduct an overview of the visibility culling techniques developed in the last decade. The taxonomy we use distinguishes point-based methods from-region methods. Point-based methods are further subdivided into object and image-precision techniques, while from-region approaches can take advantage of the cell-and-portal structure of architectural environments or handle generic scenes.