The catalytic core of RNase P

A deletion mutant of the catalytic RNA component of Escherichia coli RNase P missing residues 87-241 retains the ability to interact with the protein component to form a functional catalyst. The deletion of this phylogenetically conserved region significantly increases the Km, indicating that the deleted structures may be important for binding to the precursor tRNA substrate but not for the cleavage reaction. Under some reaction conditions, this RNase P deletion mutant can become a relatively non-specific nuclease, indicating that this RNA's catalytic center may be more exposed. The catalytic core of the RNase P is formed by less than one third of the 377 residues of the RNase P RNA.     

Stick-slip vibrations of a two degree-of-freedom geophysical fault model

This paper considers the behaviour of a two degree-of-freedom autonomous system with static and dynamic friction consisting of two blocks linked by springs on a moving belt. This system is the simplest model which has been used to simulate the dynamics of seismic faults. The friction force is assumed to be a decreasing function of the relative sliding velocity. The motion of the blocks is composed of a uniform stick motion, during which the divergence of the system is zero, and an accelerated slip motion, during which the divergence is positive. The mathematical model by definition concentrates the dissipation on the point where the slip motion ceases. It is assumed that slip occurs only in one direction. A three-dimensional Poincaré map and a scalar single variable map are discussed which characterize the dynamics of the system in a simple way. The one-dimensional map can be used to diagnose the chaotic behaviour of the full system, and quantities, similar to Lyapunov exponents, can be easily calculated which provide information regarding the system-sensitive dependence on initial conditions. The system dynamics illustrate the idea of studying the earthquake generation mechanism as a chaotic phenomenon.     

铝－锂合金中δ’（Al＿3Li）沉淀相时效粗化行为及体积分数的测定

对经固溶处理的二种Ａｌ－Ｌｉ合金（１．９４ｗｔ．％Ｌｉ和２．７５ｗｔ．％Ｌｉ）的时效过程进行了研究。结果表明：δ’的生长速率遵从Ｏｓｔｗａｒｄ粗化动力学。１．９４ｗｔ．％Ｌｉ合金δ’产生于时效过程中，而２．７５ｗｔ．％Ｌｉ合金的δ’产生于时效的前期阶段。前者的表现体积分数明显大于根据相图估算的数伍，真实体积分数则与此值接近；后者的体积分数低于根据相图估算的数值，这可能归咎于δ’固相线的位置、统计学误差及Ｌｉ更易在时效过程中贫化。     

Ratings of Therapist Dynamic Activities and Alliance Early and Late in Psychotherapy.

The present study examines the concurrent and predictive relationships between therapist psychodynamic-interpersonal activity and therapist-rated alliance. Ratings from 45 patient and therapist dyads engaged in short term psychodynamic psychotherapy from a point early (3rd or 4th session) and late (the session at which 90% of the treatment was completed) in treatment were used. The results suggest that therapists who have positive views of the alliance early in treatment also have positive views of the alliance later in treatment. Therapists who used psychodynamic-interpersonal activities early in treatment also made use of psychodynamic-interpersonal activities later in treatment. Moreover, the use of psychodynamic-interpersonal activities early in treatment was positively related to both global and specific aspects of therapist-rated alliance late in treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

BRING PLANNING DOWN TO EARTH

Applying information systems strategic planning (ISSP) theory to a practical planning effort is not a straightforward endeavor, and the penalties of a misapplied planning exercise are high. IS managers do not need another conceptual framework for ISSP as much as they need a practical point of view on driving the planning effort to produce tangible, high-quality results.     

Completeness for nondeterministic complexity classes

We demonstrate differences between reducibilities and corresponding completeness notions for nondeterministic time and space classes. For time classes the studied completeness notions under polynomial-time bounded (even logarithmic-space bounded) reducibilities turn out to be different for any class containingNE. For space classes the completeness notions under logspace reducibilities can be separated for any class properly containingLOGSPACE. Key observation in obtaining the separations is the honesty property of reductions, which was recently observed to hold for the time classes and can be shown to hold for space classes.The work of S. Homer was supported in part by National Science Foundation Grants MIP-8608137 and CCR-8814339 and a Fulbright-Hays Research Fellowship. Some of this research was done while he was a Guest Professor at the Mathematics Institute of Heidelberg University.     

Claims of alleged medical negligence in refractive surgery: causes and avoidance.

PURPOSE: To identify the issues cited in claims for alleged medical negligence in cases of refractive surgery. METHODS: One hundred and one cases of alleged medical negligence following refractive surgery were analysed by a single expert witness. Valid features of the statement of claim and issues identified by the expert as being relevant to the outcome were assessed. RESULTS: Sixty-five percentage of claims included issues of consent. In one third of these cases the Claimant had particular risk factors for which especially careful counselling was warranted. For 29% of claims there were contraindications to surgery. In 24% there was surgical error resulting in a compromised outcome. In 23% there was avoidable delay in instituting medical management for post-operative complications. Four percentage of cases were precipitated by a second opinion where the clinician giving the opinion was not fully conversant with the facts. CONCLUSIONS: The number of claims could be substantially reduced by: (1) Instituting proper policies for consent with full documentation throughout the process; (2) Ensuring that surgeons are adequately trained in evaluating pre-operative tests and allowing surgeons adequate time to assess patients prior to surgery; (3) Moderating the case-load for surgery; (4) Ensuring that patients have easy access to medical care post-operatively; (5) Keeping comprehensive and accurate records.     

Visual insights into high-resolution earthquake Simulations.

This study focuses on the visualization of a series of large earthquake simulations collectively called TeraShake. The simulation series aims to assess the impact of San Andreas Fault earthquake scenarios in Southern California. We discuss the role of visualization in gaining scientific insight and aiding unexpected discoveries.     

Family-Responsive Interventions, Perceived Organizational and Supervisor Support, Work-Family Conflict, and Psychological Strain.

This study examined organizational family-responsive policies, perceptions of the organization as family supportive, and supervisor support as issues that may be salient to the experience of conflict between paid employment (work) and family roles. Data were collected from 355 managerial personnel in New Zealand. Although work-family conflict and psychological strain were strongly linked, the availability of organizational policies had no significant association with levels of conflict or strain, whereas policy usage was related only to work-to-family interference and not to family-to-work interference. On the other hand, perceptions of the organization as family supportive and supervisor support for work-family balance displayed significant relationships with key variables, highlighting the importance of these variables for interventions designed to ameliorate the negative impact of work-family conflict on managerial well-being. Implications for the effective implementation of family-responsive interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)