The orientation and temperature dependences of dislocation velocity in Ni 3 Al single crystals

The average velocities of screw dislocations in Ni 3 Al single crystals have been directly measured as a function of resolved shear stress (RSS) and orientation in the temperature domain of the flow stress anomaly using the etch-pit technique. The velocity was found to be extremely sensitive to the RSS in all cases. In contrast with ordinary metals, the screw dislocation velocities in Ni 3 Al show anomalous behaviour; under a constant RSS, the velocities decrease dramatically with increasing temperature. Furthermore, the velocities and the tension-compression asymmetry of the velocities depend on the orientation of applied stress.     

GAIA,OCKHAM'S RAZOR,THE SCIENCE OF COMPLEXITY

In this article, the author describes his sense of synchronicity with Edgar Morin's concepts of complexity. Although Morin only briefly addresses Gaia per se, the implications of Morin's work may reveal the Gaia concept as an element of the general breakthroughs of complexity science. Morin demonstrates a phase transition that is gaining momentum right now, whereby the new, more benign science is overwhelming the old Cartesian world.     

La naturaleza y medida de la ansiedad

RESUMEN

En este artículo se presenta una caracterización general de la naturaleza y medida de la ansiedad, a través de un enfoque factorial. Gracias a éste se consigue separar la ansiedad de dos cosas con las que se confunde constantemente: La reacción a la tensión y la inadaptación de la personalidad neurótica. Las medidas más precisas de la ansiedad que ahora son posibles aclaran también la relación entre la ansiedad y un factor tal como la inteligencia, y deben ayudar a contestar muchas preguntas similares sobre la relación entre la ansiedad y varias situaciones y actuaciones.     

Handedness and Hemispheric Asymmetry in the Control Of Movements

This study investigated the influence of hemispheric specialization of function on the motor performance of the hands. Right-handed (n=17), ambidextral (n=21), and ambisinistral (n=12) subjects performed Fitts' (1954) reciprocal tapping task under two conditions with each hand. Conditions had the same index of difficulty but differed in movement precision. The left hand of righthanders was superior in the condition requiring the greatest amount of preprogramming. Conversely, the right hand was not superior in the condition having the greatest demand for feedback control. For ambidextrals, left-hand superiority in the relatively preprogrammed condition was also revealed. Ambisinistrals showed no significant difference between conditions with either hand. The results partially support the hypothesis that the motor performance of the hands mirrors the dominant processing mode of their contralateral hemisphere. Failure to find supportive evidence in ambisinistrals is consistent with the contention that they lack hemispheric specialization of function.     

Bilateral Transfer as a Function of Mental Imagery

Three experiments are reported which investigate the role of mental imagery in the bilateral transfer from right to left hand of rotary pursuit skill. In Experiment 1 both mental imagery and physical rehearsal showed significant positive transfer relative to a control condition. However, work decrement may have accumulated and transferred in the physical rehearsal group thereby depressing this group’s left-hand performance. Experiment 2 was conducted under conditions designed to allow work decrement to dissipate prior to transfer to the contralateral limb. The data still showed no difference between physical re-hearsal and mental imagery. One interpretation of these data is that work decrement was present under both the physical rehearsal and mental imagery manipulations in Experiment 1. The data from Experiment 3 confirmed this interpretation as well as replicated the positive transfer effects found for mental imagery in Experiments 1 and 2. The data are discussed in terms of central versus peripheral explanatory mechanisms.     

Impaired finger dexterity in Parkinson's disease is associated with praxis function

A controversial concept suggests that impaired finger dexterity in Parkinson’s disease may be related to limb kinetic apraxia that is not explained by elemental motor deficits such as bradykinesia. To explore the nature of dexterous difficulties, the aim of the present study was to assess the relationship of finger dexterity with ideomotor praxis function and parkinsonian symptoms. Twenty-five patients with Parkinson’s disease participated in the study. Their left and right arms were tested independently. Testing was done in an OFF and ON state as defined by a modified version of the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). Finger dexterity was assessed by a coin rotation (CR) task and ideomotor praxis using a novel test of upper limb apraxia (TULIA), in which the patients were requested to imitate and pantomime 48 meaningless, as well as communicative and tool-related gestures. Coin rotation significantly correlated with TULIA irrespective of the motor state and arm involved, but not with the MDS-UPDRS. This association was significantly influenced by Hoehn and Yahr stage.The strong association of finger dexterity with praxis function but not the parkinsonian symptoms indicates that impaired finger dexterity in Parkinson’s disease may be indeed apraxic in nature, yet, predominantly in advanced stages of the disease when cortical pathology is expected to develop. The findings are discussed within a cognitive-motor model of praxis function.     

Creencias de los profesores y estrés docente en función de la experiencia profesional

Resumen

Se investigó la relación entre las creencias de los profesores, el burnout y las diferencias de edad. Participaron 165 profesores de educación secundaria. Se evaluó: actitud hacia la profesión, fuentes de estrés; burnout; eficacia docente, competencia personal, y afrontamiento. Los resultados indicaron que en el grupo de maestros entre 46 y 60 años difirieron del resto en su actitud hacia la profesión, estrategia de afrontamiento y valor de las fuentes de estrés. El burnout fue relacionado con la creencia en la eficacia de la docencia, con una percepción pobre de la propia competencia personal y con ver las condiciones laborales como una fuente importante de estrés. La conclusión fue que el burnout docente depende de una alta expectativa y motivación para enseñar, combinada con una baja percepción de la competencia personal para resolver problemas en general.     

A psychological model that integrates ethics in engineering education

Ethics has become an increasingly important issue within engineering as the profession has become progressively more complex. The need to integrate ethics into an engineering curriculum is well documented, as education does not often sufficiently prepare engineers for the ethical conflicts they experience. Recent research indicates that there is great diversity in the way institutions approach the problem of teaching ethics to undergraduate engineering students; some schools require students to take general ethics courses from philosophical or religious perspectives, while others integrate ethics in existing engineering courses. The purpose of this paper is to propose a method to implement the integration of ethics in engineering education that is pedagogically based on Kohlberg’s stage theory of moral development.