Self-aligning fixture used in lathe chuck jaw refacing

Self-aligning tool positions and rigidly holds lathe chuck jaws for refacing and truing of the clamping surface. The jaws clamp the fixture in the manner of clamping a workpiece. The fixture can be modified to accommodate four-jawed checks

Promover la educación científica a través de las tecnologías de la información y comunicación (TIC)

La educación científica debe preparar a los estudiantes para analizar y evaluar los avances tecnológicos, desde el láser al genoma humano. A fin de planificar el cuidado de la propia salud o elegir una nueva residencia, los ciudadanos deben evaluar alternativas que reflejan avances tecnológicos. A medida que la ciencia y la tecnología avanzan, los ciudadanos necesitan desarrollar la capacidad de responder a nuevas alternativas y de criticar mensajes persuasivos sobre muchas cosas, desde medicamentos hasta materiales de construcción. El Web-based Inquiry Science Environment (WISE) ayuda a los estudiantes y diseñadores de currículo que buscan alcanzar estos objetivos. A medida que experimentamos con programas educativos para alcanzar estos objetivos, nos beneficiamos de la colaboración internacional y de la comunicación. Cuanto más podamos aprender los unos de los otros, más puede mejorar nuestra educación científica.Science education must prepare students to analyze and assess advances in technology from lasers to the human genome. To plan one's health care or select a new residence, citizens must evaluate alternatives that reflect technological advances. As science and technology advance, citizens need the ability to respond to new alternatives and to criticize persuasive messages about everything from drugs to building materials. The Web-based Inquiry Science Environment (WISE) supports students and curriculum designers who seek to achieve these goals. As we experiment with educational programs to meet these goals we benefit from international collaborations and communication. The more we can learn from each other the better our science education can become

International Security and the War Powers Resolution

In recent history, the authority to commit US. troops to theaters of conflict has shifted from Congress to the President. After the Vietnam War, the War Powers Resolution was written to reestablish balanced authority over war between the political branches of government. In the post-Cold War era, forces frequently are deployed as part of multilateral UN. operations. This trend creates two contradictory needs: first, the need for the Executive to be able to act swiftly and decisively in formulating military commitments to the United Nations, and second, the need for Congress to authorize potentially long-term military deployments. To reconcile these contradictory needs, the President should be required to consult with a small group of key congressional actors before committing US. troops. to multilateral UN, military operations. There are both legal and security rationales for this. Centrally, Executive-congressional consultation re-solidifies the constitutional allocation of war powers and may bolster US. credibility in multilateral operations

An Empirical Investigation of Debt Contract Design: The Determinants of the Choice of Debt Terms in Eurobond Issues

This paper provides a comprehensive analysis of the determinants for the optimal choice of contract terms on Eurobonds issued by UK companies. We examine predictions of extant theories that associate the choice of debt features namely, maturity, call options, convertible options, and protective covenants to firm and market characteristics. Like in Correia (2003), a simultaneous equations approach is adopted to test the alternative use of contract features for mitigating debt-contracting costs. The evidence provides strong support to the prediction that both callable and short-term debt and convertible and debt with protective covenants are used as alternative control devises to mitigate agency costs. Further evidence suggests, however, that contrary to the fundamentals guiding the choice of maturity and callability structures, the use of conversion options and protective covenants in Eurobond contracts seems to be determined by equity agency costs rather than debt agency costs. Also, some support is found for the risk uncertainty theory underlying the use of convertibles and for liquidity risk arguments regarding the choice to include protective covenants.

Corporate Governance and Executive Perquisites

Purpose The purpose of this paper is to examine the relation between executive perquisite consumption and indicators of corporate governance after the Securities and Exchange Commission (SEC) expanded the disclosure requirements related to perquisites. Design/methodology/approach This study uses ordinary least squares and Tobit regressions to examine the dollar value of perquisites consumed, the number of perquisites consumed and the types of perquisites consumed. Findings The analysis shows that firms with weak corporate governance are more likely to award perquisites to executives. Firms characterized as being more prone to the presence of agency problems are associated with greater levels of perquisite consumption. Finally, there is evidence that not all perquisite consumptions can be attributed to an agency problem. Efficiently operating firms are associated with greater levels of perquisite consumption as are larger firms. Research limitations/implications The authors examine firms in the period immediately after the SEC initiated the expanded disclosures. This may limit the generalizability of the results to other exchange-listed firms that changed their perquisite policy as a result of the rule change. Originality/value The paper extends the literature on corporate governance and mandatory corporate disclosure by investigating the association between corporate governance characteristics and perquisite consumption. This paper examines this relation immediately after the SEC expanded the disclosures surrounding perquisites to provide the public with more transparent disclosures

Corporate governance and the nature of takeover resistance

We investigate the relation between corporate governance characteristics of hostile takeover targets and the choice to employ 'harmful' resistance that is not perceived as being motivated by shareholders' interests. We find that harmful resistance is associated with firms where managers have more pronounced ownership-based and age-related incentives for control, and directors have equity interests less aligned to stockholders. These firms also have less independent boards, are exposed to weaker discipline from outside blockholders, and are inferior performers. In the presence of harmful resistance, the market is less optimistic about the chances of bid completion, and there is a greater likelihood of managerial turnover

Toward a script theory of guidance in computer-supported collaborative learning

This article presents an outline of a script theory of guidance for computer-supported collaborative learning (CSCL). With its four types of components of internal and external scripts (play, scene, role, and scriptlet) and seven principles, this theory addresses the question how CSCL practices are shaped by dynamically re-configured internal collaboration scripts of the participating learners. Furthermore, it explains how internal collaboration scripts develop through participation in CSCL practices. It emphasizes the importance of active application of subject matter knowledge in CSCL practices, and it prioritizes transactive over non-transactive forms of knowledge application in order to facilitate learning. Further, the theory explains how external collaboration scripts modify CSCL practices and how they influence the development of internal collaboration scripts. The principles specify an optimal scaffolding level for external collaboration scripts and allow for the formulation of hypotheses about the fading of external collaboration scripts. Finally, the article points towards conceptual challenges and future research questions

Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme

Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning

Design approaches in technology enhanced learning

Design is a critical to the successful development of any interactive learning environment (ILE). Moreover, in technology enhanced learning (TEL), the design process requires input from many diverse areas of expertise. As such, anyone undertaking tool development is required to directly address the design challenge from multiple perspectives. We provide a motivation and rationale for design approaches for learning technologies that draws upon Simon's seminal proposition of Design Science (Simon, 1969). We then review the application of Design Experiments (Brown, 1992) and Design Patterns (Alexander et al., 1977) and argue that a patterns approach has the potential to address many of the critical challenges faced by learning technologists