Corrosion behaviour of porous Ti intended for biomedical applications

Porous Ti implants are being developed inorder to reduce the biomechanical mismatch between theimplant and the bone, as well as increasing the osseointegrationby improving the bone in-growth. Most of the focusin the literature has been on the structural, biological andmechanical characterization of porous Ti whereas there islimited information on the electrochemical characterization.Therefore, the present work aims to study the corrosionbehaviour of porous Ti having 30 and 50 % ofnominal porosity, produced by powder metallurgy routeusing the space holder technique. The percentage, size anddistribution of the pores were determined by image analysis.Electrochemical tests consisting of potentiodynamicpolarization and electrochemical impedance spectroscopywere performed in 9 g/L NaCl solution at body temperature.Electrochemical studies revealed that samples presenteda less stable oxide film at increased porosity, morespecifically, the complex geometry and the interconnectivityof the pores resulted in formation of less protectiveoxide film in the pores.This study was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalizac¸a˜o (POCI) with the reference project POCI-01-0145- FEDER-006941, Programa de Acc¸o˜es Universita´rias Integradas LusoFrancesas’ (PAUILF TC-12_14), and The Calouste Gulbenkian Foundation through ‘‘Programa de Mobilidade Acade´mica para Professores’’. The authors would also like to acknowledge Prof. Ana Senos (University of Aveiro) and Prof. Jose´ Carlos Teixeira (University of Minho) for the provision of the characterization facilities.info:eu-repo/semantics/publishedVersio

Generalized Learning Problems and Applications to Non-commutative Cryptography

Abstract. We propose a generalization of the learning parity with noise (LPN) and learning with errors (LWE) problems to an abstract class of group-theoretic learning problems that we term learning homomorphisms with noise (LHN). This class of problems contains LPN and LWE as spe-cial cases, but is much more general. It allows, for example, instantiations based on non-abelian groups, resulting in a new avenue for the applica-tion of combinatorial group theory to the development of cryptographic primitives. We then study a particular instantiation using relatively free groups and construct a symmetric cryptosystem based upon it

The Opinions of Italian Psychology Students About People Diagnosed with Depression and Schizophrenia: A Comparative Study

This study explored the opinions about depression and schizophrenia among Italian psychology students, and whether students’ opinions changed during education. Of the 705 students who read a description of depression (N = 275) or schizophrenia (N = 430) and then completed a questionnaire on their opinions about the disorder, 490 made a correct diagnosis (depression = 243/275; schizophrenia: 247/430) and were included in the study. Compared to schizophrenia-group students, depression-group students: more frequently mentioned psychosocial factors and less frequently heredity among the causes; were more convinced about the usefulness of psychological therapies and less about pharmacotherapies; had more prognostic optimism; had lower perception of unpredictability and dangerousness. Compared to first-year students, fifth-year students (depression = 105; schizophrenia = 162): in both diagnostic groups more frequently cited heredity among the causes; in depression group, had lower perception of unpredictability; in schizophrenia group, had higher perception of dangerousness and more prognostic pessimism. More education about stigma should be provided to psychology students

Avoiding Deadlock Using Pricing Strategies for Networks of Intelligent Personal Assistants

this paper, we investigate the robustness of one strategy, via simulations. A lot of work still needs to be done to find robust strategies in general. Our notion of stability di#ers from the conjectural equilibrium of Wellman and Hu [13]. We are not able yet to prove an optimum, as for Nash equilibria. Our agents are myopic, similar to [1, 8]. Our approach can also be seen as money-based negotiation in contract nets. We have explored this further in [5] 2 Network of intelligent personal assistants In the sequel, PA or automatic PA refers to a computer. The term real PA refers to a human being. A PA's user can be a real PA, or the boss of a real PA. Many statements apply to automatic PA's as well as real PA'

Building Electronic Marketplaces with the ZEUS Agent Toolkit

There is an emerging desire amongst agent researchers to move away from point solutions in favour of developing methodologies and tool-kits for building distributed multi-agent systems. This philosophy has led researchers at BT Labs to develop the ZEUS Agent Building Tool-kit, which facilitates the engineering of future agent applications through a library of agent-level components. The ZEUS tool-kit is currently being used to create a prototype distributed multi-agent electronic marketplace within our local area network. By employing the ZEUS agent class library this application has been implemented rapidly by two developers. ZEUS agents were not specifically designed for electronic commerce applications and so new functionality has been added that enables our agents to participate in auctions, and enables users to communicate information about transactions to their agents. Our experimental marketplace shares many features with existing agent-based auction systems, such as the dynamic..

Robust Stable Strategies for Networks of Intelligent Personal Assistants

. The first half of this paper defines a realistic automatic personal assistant. Such an assistant is a process that controls a single resource in time. The resource has a location, a value, and a descriptor. All three can change in time. In the second half, we consider a network of automatic personal assistants that exchange resources, either immediately, or at a certain moment in the future. In practice, this means that the personal assistant book time-slots with other assistants. We show that a network of such assistants will continue operating without deadlock if the personal assistants can buy and sell time-slots in a free market with inflation and discount on bankruptcy. We found that this strategy is robust. 1. Stable strategies In this work, we describe a stable strategy for a realistic large scale distributed system. This system consists of automatic personal assistants (PA's) that can book time-slots in each other's diaries, and that have to pay for doing so. Stability of st..

Stability, Fairness and Scalability of Multi-Agent Systems

: We study a general network of agents that can be built with Zeus [18]. Relationships between agents can be peer, slave, master, discounter, or no relation at all. There are four possible strategies: the cheapest agent is selected, preference to slaves rst, cut-price discounting based on the utility, and cheapest agent chosen, but preference given to cheapest slave. The cost of a task for the agent originating it, is the cost of the resources used. The size of the initial endowment is determined so that there are never any lost tasks in the system. We also establish the inuence of agent strategies on stability and fairness. We were able to determine how much discounting the agents can allow, and how to control the coordination time. The growth of the maximum communication load with respect to the number of agents is calculated for various topologies of networks of agents. A performance measure related to the speed of the network is also calculated. Keywords: Intelligent ag..