Search results for "ROUGH"

Visual Contrast Modulates Operant Learning Responses in Larval Zebrafish.

2018

The larval zebrafish is a promising vertebrate model organism to study neural mechanisms underlying learning and memory due to its small brain and rich behavioral repertoire. Here, we report on a high-throughput operant conditioning system for zebrafish larvae, which can simultaneously train 12 fish to associate a visual conditioned pattern with electroshocks. We find that the learning responses can be enhanced by the visual contrast, not the spatial features of the conditioned patterns, highlighted by several behavioral metrics. By further characterizing the learning curves as well as memory extinction, we demonstrate that the percentage of learners and the memory length increase as the co…

The water shuttling hypothesis in Lithops

2011

Una más de la familia. Au pairs atrapadas entre el capital humano y la economía moral

2018

In contemporary societies we are witnessing an expansion of the messages of human capital. These messages have as their central dimension idea of the self-entrepreneur, which implies a deepening in the logic of activation, while blurring the wage relations. In this scenario, young people with university degrees are becoming a favourite target in the offensive of human capital. The penetration of these human capital messages can be seen in the discourses of young university students who have been forced to leave the country during the crisis. In the present text we approach the discourses of young women who came out as au pairs. The characteristics of this figure place it in a space halfway …

Underwater Multirobot Cooperative Intervention MAC Protocol

2020

This work introduces a Medium Access Control (MAC) protocol designed to allow a group of underwater robots that share a wireless communication channel to effectively communicate with each other. The goal of the Underwater Multirobot Cooperative Intervention MAC (UMCI-MAC) protocol presented in this work is to minimize the end to end delay and the jitter. The access to the medium in UMCI-MAC follows a Time Division Multiple Access (TDMA) strategy which is arbitrated by a master, which also has the capability to prioritize the transmission of some nodes over the rest of the network. Two experiments have been carried out with a team of four Autonomous Underwater Vehicles (AUV) in order to comp…

Trajectory Design and Resource Allocation for Multi-UAV Networks : Deep Reinforcement Learning Approaches

2023

The future mobile communication system is expected to provide ubiquitous connectivity and unprecedented services over billions of devices. The unmanned aerial vehicle (UAV), which is prominent in its flexibility and low cost, emerges as a significant network entity to realize such ambitious targets. In this work, novel machine learning-based trajectory design and resource allocation schemes are presented for a multi-UAV communications system. In the considered system, the UAVs act as aerial Base Stations (BSs) and provide ubiquitous coverage. In particular, with the objective to maximize the system utility over all served users, a joint user association, power allocation and trajectory desi…

Numerical analysis of the mechanical response of wood glulam beams reinforced through the thickness by FRP rods

2009

The modern use of through-thickness reinforcement in wood glulam (glued laminated) beams, bridging the potential delamination crack faces, has shown to be an effective technological solution to improve their interlaminar fracture strength. In this paper, the behaviour of wood glulam beams is investigated from an experimental and numerical point of view, comparing the mechanical response of unreinforced and reinforced (by FRP rods) beams subjected to four points bending tests. For the numerical analysis, a simple two-phases (joint and reinforcement) interface model has been formulated and implemented in a finite element code. In particular, the classical interface model for adhesive joint, a…

La organización del trabajo por proyectos: La fábrica de la precariedad laboral

2019

The project-based organization, considered as a radical reorganization of work around one or more simultaneous projects, is nowadays widespread in large companies and public administrations. According to the managerial way of thinking, this system would be virtuous: by giving more autonomy to the employees in the act of production and by developing their skills through mobility and interdisciplinarity of work teams, it would be able to arouse their full commitment. This study confirms in some way how this opinion has been imposed, but at the expense of precarious working conditions, increasing the dedication of employees and silencing any form of criticism. The research is based on a review…

Etude en champ proche et champ lointain de surfaces métalliques : apport des microscopies à sonde locale à l'étude des étalons de masse

2005

Among the international system of units (SI) the kilogram is the only one which is still defined by a material artefact, the international prototype of the platinum iridium kilogram. The instability of mass standards is one of the major concerns of national metrology institutes and the subject of numerous studies. Interest in microscopic studies of surface quality of a mass has grown, as it is well known that surface roughness is a factor in determining the long-term stability of mass standards. This thesis is devoted to the study in near field and far field for determining the topography and roughness of metallic surfaces, in related with different institute, national and international met…