Electron exchange coupling for single-donor solid-state spin qubits

Intervalley interference between degenerate conduction band minima has been shown to lead to oscillations in the exchange energy between neighboring phosphorus donor electron states in silicon [B. Koiller, X. Hu, and S. Das Sarma, Phys. Rev. Lett. 88, 027903 (2002); Phys. Rev. B 66, 115201 (2002)]. These same effects lead to an extreme sensitivity of the exchange energy on the relative orientation of the donor atoms, an issue of crucial importance in the construction of silicon-based spin quantum computers. In this article we calculate the donor electron exchange coupling as a function of donor position incorporating the full Bloch structure of the Kohn-Luttinger electron wave functions. It is found that due to the rapidly oscillating nature of the terms they produce, the periodic part of the Bloch functions can be safely ignored in the Heitler-London integrals as was done by Koiller, Hu, and Das Sarma, significantly reducing the complexity of calculations. We address issues of fabrication and calculate the expected exchange coupling between neighboring donors that have been implanted into the silicon substrate using an 15 keV ion beam in the so-called top down fabrication scheme for a Kane solid-state quantum computer. In addition, we calculate the exchange coupling as a function of the voltage bias on control gates used to manipulate the electron wave functions and implement quantum logic operations in the Kane proposal, and find that these gate biases can be used to both increase and decrease the magnitude of the exchange coupling between neighboring donor electrons. The zero-bias results reconfirm those previously obtained by Koiller, Hu, and Das Sarma.

Broadening conceptions of curriculum for young people: Reports from three student-teachers on exchange

Research reports prepared by three Australian preservice teachers--Paula Shaw, Chris Sharp and Scott McDonald--undertaking their teacher education practicum in Canada, form the basis of this paper. The reports provide critical insights into three aspects of education for young people in both Canada and Australia. They also provide critical insight into the ways in which a practicum research project, along with the opportunities afforded through an international experience, enabled the preservice teachers to broaden their understanding of the curriculum for young people, of issues relevant to the diverse needs of young people, and of themselves and their priorities as teachers. The preservice teachers investigated three topics: attempts to reduce homophobia in schools; the presence or absence of Aboriginal content in the school curricula in British Columbia and Queensland; and "schools-within-schools" as a means to meet the needs of diverse student populations. Linda Farr Darling from the University of British Columbia provides a response to the three reports.

The European Union and the Member States: two different perceptions of border

Abstract In this article we analyze two different perceptions of border inside Europe. On the one hand, we have the perception idealized by the European Union as an international organization, which believes that states benefit more from cooperation and dilution of borders in a common space than from keeping its borders as a symbol of its sovereignty. On the other hand, we have the European member states, taken individually, with particular interests and goals that, given the threat of illegal immigration, which is currently felt in the large-scale Europe, adopt a realistic perception of the border, and look at each territory as a space that needs protection from external threats. Following this argument, we reason that the current construction of walls in several European countries reflects the rebirth of a realistic perception of the border, and this is one more challenge for Europe regarding its unity and solidarity. Is this the end of the Schengen Agreement? What is going to happen to the European project if each state unilaterally adopts a strategy to deal with illegal immigration and refugees that are coming to Europe? Can immigration lead to a retrocession of the EU idealist significance of border?

The ICT use in the implementation of Directive 2011/24/EU

This article has as main objective to evaluate the role of information and communication technologies (ICTs), in particular the eHealth (electronic health), in the implementation of the directive 2011/24/EU, of the European Parliament and of the Council of March 9th, on the exercise of patients' rights in cross-border healthcare within Member States of European Union. Being currently underway the deadline for transposition of the Directive, it is important to analyze the probable results for national health systems. Innovatively, the Directive specifically proposes the implementation of a European network of eHealth in the provision of cross-border healthcare. Within ICT, we focus on telemedicine as a key tool for the implementation, on a context of public budgets constrains. In this context, it is assumed that the EU will support and promote cooperation and the exchange of scientific information between member states within the framework of a voluntary network composed by the national authorities responsible for health (or eHealth). We apply the S.W.O.T. (strengths and weaknesses, opportunities and threats) analysis to forecast the main points that should be focused on deeper research. We discuss the technological, economic and social aspects of the use of ICT on the implementation of the directive. It is thus important to evaluate the context of ICT by S.W.O.T. tool to define strategies to sensitize policy-makers, health managers, and citizens, in order to be able to turn threats into opportunities and mitigating the weaknesses in the implementation of the Directive and to promote a better healthcare access for citizens, ensuring safe, effective healthcare and with different quality.

STOCK EXCHANGE LISTING INDUCES SOPHISTICATION OF CAPITAL BUDGETING

This article compares capital budgeting techniques employed in listed and unlisted companies in Brazil. We surveyed the Chief Financial Officers (CFOs) of 398 listed companies and 300 large unlisted companies, and based on 91 respondents, the results suggest that the CFOs of listed companies tend to use less simplistic methods more often, for example: NPV and CAPM, and that CFOs of unlisted companies are less likely to estimate the cost of equity, despite being large companies. These findings indicate that stock exchange listing may require greater sophistication of the capital budgeting process.

La social stock exchange au Portugal: un nouvel allié de l'économie sociale

Résumé Cet article vise à contribuer à la connaissance de la Bolsa de Valores Sociais (BVS) — Social Stock Exchange — récemment créé au Portugal, dont le but primatial était de permettre la prise de moyens de financement des entités de l'Économie Sociale engagées dans des projets d'éducation et d'entreprenariat. Il se penchera sur la qualification juridique des divers types d'entités cotées dans la BVS, sur le concept d'investisseur social et sur la protection dont il jouira, vis-à-vis des exigences de transparence et de gouvernance qui incombent à ces entités. Le thème proposé sera examiné en soulignant les virtualités et le potentiel de la BVS, faisant référence à l'un ou à l'autre sujet qui viennent à effet, avec un accent particulier sur l'avantage d'élaborer un code de gouvernance corporative pour les entités de l'Économie Sociale. Abstract This article aims to contribute to the knowledge of the Bolsa de Valores Sociais (BVS) — Social Stock Exchange — recently created in Portugal, whose primatial purpose was to allow the taking of means of financing the Social Economy entities, engaged in projects in education and entrepreneurship. It will reflect on the legal classification of the various types of entities rated in the BVS, on the concept of social investor and on the protection he will enjoy, leading to the consequent demands for transparency and governance that falls upon those entities. The proposed theme will be discussed highlighting the virtues and potential of BVS, playing in one or two topics that comes to purpose, with particular emphasis on the relevance of drawing up a code of corporate governance for entities of the Social Economy. Resumen Este artículo tiene como objetivo contribuir al conocimiento de la Bolsa de Valores Sociales (BVS), recientemente creada en Portugal, cuya finalidad principal es que las entidades de la economía social dedicadas a proyectos en las áreas de educación y de iniciativa empresarial puedan obtener medios financieros. Se abordará la calificación jurídica de los diversos tipos de entidades que cotizan en la BVS, así como el concepto de inversor social y la protección de que éste goza, con las consiguientes exigencias en materia de transparencia y de gobierno que recaen sobre esas entidades. Se analizará la temática propuesta destacando las virtudes y potencialidades de la BVS, sin omitir algún otro tópico adyacente que resulte relevante, en especial la conveniencia de que sea elaborado un código de gobernanza corporativa para las entidades de la economía social.

Personality, emotion, and mood in agent-based group decision making

Group decision making plays an important role in organizations, especially in the present-day economy that demands high-quality, yet quick decisions. Group decision-support systems (GDSSs) are interactive computer-based environments that support concerted, coordinated team efforts toward the completion of joint tasks. The need for collaborative work in organizations has led to the development of a set of general collaborative computer-supported technologies and specific GDSSs that support distributed groups (in time and space) in various domains. However, each person is unique and has different reactions to various arguments. Many times a disagreement arises because of the way we began arguing, not because of the content itself. Nevertheless, emotion, mood, and personality factors have not yet been addressed in GDSSs, despite how strongly they influence results. Our group’s previous work considered the roles that emotion and mood play in decision making. In this article, we reformulate these factors and include personality as well. Thus, this work incorporates personality, emotion, and mood in the negotiation process of an argumentbased group decision-making process. Our main goal in this work is to improve the negotiation process through argumentation using the affective characteristics of the involved participants. Each participant agent represents a group decision member. This representation lets us simulate people with different personalities. The discussion process between group members (agents) is made through the exchange of persuasive arguments. Although our multiagent architecture model4 includes two types of agents—the facilitator and the participant— this article focuses on the emotional, personality, and argumentation components of the participant agent.

New insights on integer-programming models for the kidney exchange problem

In recent years several countries have set up policies that allow exchange of kidneys between two or more incompatible patient–donor pairs. These policies lead to what is commonly known as kidney exchange programs. The underlying optimization problems can be formulated as integer programming models. Previously proposed models for kidney exchange programs have exponential numbers of constraints or variables, which makes them fairly difficult to solve when the problem size is large. In this work we propose two compact formulations for the problem, explain how these formulations can be adapted to address some problem variants, and provide results on the dominance of some models over others. Finally we present a systematic comparison between our models and two previously proposed ones via thorough computational analysis. Results show that compact formulations have advantages over non-compact ones when the problem size is large.

The capacity exchange protocol

This paper proposes a new strategy to integrate shared resources and precedence constraints among real-time tasks, assuming no precise information on critical sections and computation times is available. The concept of bandwidth inheritance is combined with a capacity sharing and stealing mechanism to efficiently exchange bandwidth among tasks to minimise the degree of deviation from the ideal system’s behaviour caused by inter-application blocking. The proposed Capacity Exchange Protocol (CXP) is simpler than other proposed solutions for sharing resources in open real-time systems since it does not attempt to return the inherited capacity in the same exact amount to blocked servers. This loss of optimality is worth the reduced complexity as the protocol’s behaviour nevertheless tends to be fair and outperforms the previous solutions in highly dynamic scenarios as demonstrated by extensive simulations. A formal analysis of CXP is presented and the conditions under which it is possible to guarantee hard real-time tasks are discussed.

Impact of europeanization in policy network governance pattrons

Comunicação apresentada na 30th Sunbelt Social Networks Conference, em Riva del Garda, Itália, a 3 de Julho de 2010.

Cantor exchange systems and renormalization

We prove a one-to-one correspondence between (i) C1+ conjugacy classes of C1+H Cantor exchange systems that are C1+H fixed points of renormalization and (ii) C1+ conjugacy classes of C1+H diffeomorphisms f with a codimension 1 hyperbolic attractor Lambda that admit an invariant measure absolutely continuous with respect to the Hausdorff measure on Lambda. However, we prove that there is no C1+alpha Cantor exchange system, with bounded geometry, that is a C1+alpha fixed point of renormalization with regularity alpha greater than the Hausdorff dimension of its invariant Cantor set.

Arc exchange systems and renormalization

We exhibit the construction of stable arc exchange systems from the stable laminations of hyperbolic diffeomorphisms. We prove a one-to-one correspondence between (i) Lipshitz conjugacy classes of C(1+H) stable arc exchange systems that are C(1+H) fixed points of renormalization and (ii) Lipshitz conjugacy classes of C(1+H) diffeomorphisms f with hyperbolic basic sets Lambda that admit an invariant measure absolutely continuous with respect to the Hausdorff measure on Lambda. Let HD(s)(Lambda) and HD(u)(Lambda) be, respectively, the Hausdorff dimension of the stable and unstable leaves intersected with the hyperbolic basic set L. If HD(u)(Lambda) = 1, then the Lipschitz conjugacy is, in fact, a C(1+H) conjugacy in (i) and (ii). We prove that if the stable arc exchange system is a C(1+HDs+alpha) fixed point of renormalization with bounded geometry, then the stable arc exchange system is smooth conjugate to an affine stable arc exchange system.