PhenoWorld : a new paradigm to screen rodent behavior

Modeling depression in animals has inherent complexities that are augmented by intrinsic difficulties to measure the characteristic features of the disorder. Herein, we describe the PhenoWorld (PhW), a new setting in which groups of six rats lived in an ethological enriched environment, and have their feeding, locomotor activity, sleeping and social behavior automatically monitored. A battery of emotional and cognitive tests was used to characterize the behavioral phenotype of animals living in the PhW and in standard conditions (in groups of six and two rats), after exposure to an unpredictable chronic mild stress paradigm (uCMS) and antidepressants. Data reveal that animals living in the PhW displayed similar, but more striking, behavioral differences when exposed to uCMS, such as increased behavioral despair shown in the forced swimming test, resting/sleep behavior disturbances and reduced social interactions. Moreover, several PhW-cage behaviors, such as spontaneous will to go for food or exercise in running wheels, proved to be sensitive indicators of depressive-like behavior. In summary, this new ethological enriched paradigm adds significant discriminative power to screen depressive-like behavior, in particularly rodent's hedonic behavior

LOW-Γ JETS from COMPACT STELLAR MERGERS: CANDIDATE ELECTROMAGNETIC COUNTERPARTS to GRAVITATIONAL WAVE SOURCES

The American Astronomical Society. All rights reserved.Short gamma-ray bursts (GRBs) are believed to be produced by relativistic jets from mergers of neutron stars (NSs) or NSs and black-holes (BHs). If the Lorentz-factors Γ of jets from compact stellar mergers follow a similar power-law distribution to those observed for other high-energy astrophysical phenomena (e.g., blazars, active galactic nuclei), the population of jets should be dominated by low-Γ outflows. These jets will not produce prompt gamma-rays, but jet energy will be released as X-ray/optical/radio transients when they collide with the ambient medium. Using Monte Carlo simulations, we study the properties of such transients. Approximately 78% of merger jets Mpc result in failed GRBs if the jet Γ follows a power-law distribution of index -1.75. X-ray/optical transients from failed GRBs will have broad distributions of their characteristics: light-curves peak tp ∼ 0.1-10 days after a merger; flux peaks for X-ray 10-6 mJy ≲ Fx ≲ 10-2 mJy; and optical flux peaks at 14 ≲ mg ≲ 22. X-ray transients are detectable by Swift XRT, and ∼85% of optical transients will be detectable by telescopes with limiting magnitude mg ≳ 21, for well localized sources on the sky. X-ray/optical transients are followed by radio transients with peak times narrowly clustered around tp ∼ 10 days, and peak flux of ∼10-100 mJy at 10 GHz and ∼0.1 mJy at 150 MHz. By considering the all-sky rate of short GRBs within the LIGO/Virgo range, the rate of on-axis orphan afterglows from failed GRBs should be 2.6(26) per year for NS-NS(NS-BH) mergers, respectively. Since merger jets from gravitational-wave (GW) trigger events tend to be directed to us, a significant fraction of GW events could be associated with the on-axis orphan afterglow

Interests of 5 axis toolpaths generation for Wire Arc Additive Manufacturing of aluminum alloys

Additive Manufacturing (AM) for metal part can be divided into two different types: The powder technology and the wire technology. Usually, powder is adapted for fine components and small parts whereas wire is used for structural components and large scale part. One of the main benefits of AM is to simplify assemblies by reducing the number of components and to provide a large freedom of design. A standard AM system consists of a combination of three blocks: a motion system, a heat source and a feedstock. For Wire Arc Additive Manufacturing (WAAM), the heat source is a welding generator and the feedstock is a wire. The motion system generally used is a 6 axis robot or a CNC machine. This paper aims to propose a methodology to generate 5 axis toolpaths for WAAM and highlight the main parameters which selection is a key issue to resolve. The goal is to compare 3 axis and 5 axis toolpaths on part accuracy, depending the clearance angle of the part

VERNE - A five-axis parallel kinematics milling machine

Ten years ago a new kind of machine tool was presented in Chicago, based on parallel kinematics architectures. Since then, many of these parallel kinematics machines (PKMs) have been developed around the world. Their main interest lies in their high dynamic characteristics, which could help in going faster in high-speed milling. In order to develop high-speed milling on PKM tools and to highlight their potentialities, the French laboratory IRCCyN is now equipped with the VERNE. This PKM tool has been developed by the Spanish company Fatronik. However, the high-speed milling production process is a complex task, in which a great number of parameters influence the final precision of the part and the productivity of the machine. For example, the NC (numerical control) and computer-aided manufacturing (CAM) parameters (feed forward, milling strategies, etc.), the piece geometry, the machine structure, the tool, etc., have a direct consequence on the final part. Hence, a method has been developed in order to check the capability of the machine (either serial or parallel) in milling, which relies on two approaches. The first one is an experimental approach (either using a coordinate measuring machine or acquiring the output axis encoders), while the second one is a simulated approach. After introducing the kinematics of the VERNE, the experimental approach performed so far will be presented.Peer reviewe

A New Strategy of Tool Path Planning Based on Hydrodynamic Data to Machine Marine Propeller

Marine propellers are complex surfaces that are usually machined with a perfect roughness in order not to disturb the theoretical flow. Because this requirement is penalizing from a manufacturing point of view, the global objective of the study is to propose an approach in which the machining parameters are linked to functional properties of the blade in order to remove the polishing phase. To reach this objective, hydrodynamic data are used: streak lines, that are computed during the propeller design phase, characterize the fluid behavior at the close vicinity of the blade. Those lines, which are theoretically continuous at the leading edge, turn out to be discontinuous, due to the computing method. To be consistent with the fluid behavior as much as possible, the idea presented in the paper is to compose a continuous trajectory, especially at the leading edge, to mill the surface. Thus, an algorithm is developed to plan tool paths which are smoothed at leading edge using Bezier curves. Moreover, this algorithm allows to quantify the cusp height at the leading edge to avoid a drop in performance using criteria linked to the dynamical behavior of a five axis machine tool. In this work, a strategy is developed and enables multiaxial milling of a blade surface by using geometric and hydrodynamic data and by respecting the associated constraints

Design for manufacturing with tool paths adapted to marine propeller

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