Laser absorption phenomena in flowing gas devices

A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster

The Concept of Man in the Spanish Renaissance

Paper by Otis H. Green, from the University of Pennsylvani

Metacognition : a valuable aid to understanding for medical students in problem-based learning

This study involved the first year medical students at the University of Glasgow and was designed to instil the students with metacognition. The students were briefly introduced to the concepts of context specificity, rote memorisation, and the variation in leaning styles. They were then given instruction in concept mapping stressing the metacognitive comfort of chunking and linking information. Emphasis was placed on thoughtful reflection and the integration of various disciplines. The students were told that the quality and effectiveness of their concept maps could not be assessed by anyone else. Following their normal process the students, in small groups, read the patient scenario, listed the main issues on the board and discussed each in turn. When the discussion was completed six to eight questions were generated based on gaps in knowledge highlighted during the discussion. The students individually sought answers to the questions posed. Before returning to their group for a final discussion of the questions the test subjects were asked to: put away all notes and texts, reread the scenario, using the 3-part NCR form provided construct a concept map indicating how you understand the problem, tear off bottom page of the form. The students were then instructed to take out notes and texts and make any corrections or additions desired, then tear off the bottom page of their form. The two concept maps were turned in at the beginning of the next PBL session. The students retained the top sheet of the 3-part form for their notes. Data was collected from 9 PBL groups for 10 scenarios, 546 2-part maps in all. The collected concept maps were analysed for general layout and quantity of data but not for accuracy. This analysis yielded some insight into concept formation and a quite surprising consistency of data bits for an individual over a variety of scenarios

A reinforcing circuit action of extrasynaptic GABAA receptor modulators on cerebellar granule cell inhibition.

GABAA receptors (GABARs) are the targets of a wide variety of modulatory drugs which enhance chloride flux through GABAR ion channels. Certain GABAR modulators appear to acutely enhance the function of δ subunit-containing GABAR subtypes responsible for tonic forms of inhibition. Here we identify a reinforcing circuit mechanism by which these drugs, in addition to directly enhancing GABAR function, also increase GABA release. Electrophysiological recordings in cerebellar slices from rats homozygous for the ethanol-hypersensitive (α6100Q) allele show that modulators and agonists selective for δ-containing GABARs such as THDOC, ethanol and THIP (gaboxadol) increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in granule cells. Ethanol fails to augment granule cell sIPSC frequency in the presence of glutamate receptor antagonists, indicating that circuit mechanisms involving granule cell output contribute to ethanol-enhancement of synaptic inhibition. Additionally, GABAR antagonists decrease ethanol-induced enhancement of Golgi cell firing. Consistent with a role for glutamatergic inputs, THIP-induced increases in Golgi cell firing are abolished by glutamate receptor antagonists. Moreover, THIP enhances the frequency of spontaneous excitatory postsynaptic currents in Golgi cells. Analyses of knockout mice indicate that δ subunit-containing GABARs are required for enhancing GABA release in the presence of ethanol and THIP. The limited expression of the GABAR δ subunit protein within the cerebellar cortex suggests that an indirect, circuit mechanism is responsible for stimulating Golgi cell GABA release by drugs selective for extrasynaptic isoforms of GABARs. Such circuit effects reinforce direct actions of these positive modulators on tonic GABAergic inhibition and are likely to contribute to the potent effect of these compounds as nervous system depressants

Mediation by Judges: A New Phenomenon in the Transformation of Justice

This article has three principal parts. In the first, we present an overview of judicial mediation and how it responds to some of the perceived problems with the classical model of adjudication. In this analysis, we draw especially on the experience with judicial mediation at the appellate level at the Quebec Court of Appeal. In the second part, we examine the unfolding of the mediation process itself, using an annotated guide to judicial mediation to address broader issues of both practical and theoretical concern. In the third part, we consider the crucial question of ethics in mediation, signaling some of the problems in applying ethical models developed in the context of classical adversarial litigation and advocacy to mediation. Finally, we conclude by suggesting some continuing challenges and subjects for further study

Quantified Uncertainty in Thermodynamic Modeling for Materials Design

Phase fractions, compositions and energies of the stable phases as a function of macroscopic composition, temperature, and pressure (X-T-P) are the principle correlations needed for the design of new materials and improvement of existing materials. They are the outcomes of thermodynamic modeling based on the CALculation of PHAse Diagrams (CALPHAD) approach. The accuracy of CALPHAD predictions vary widely in X-T-P space due to experimental error, model inadequacy and unequal data coverage. In response, researchers have developed frameworks to quantify the uncertainty of thermodynamic property model parameters and propagate it to phase diagram predictions. In previous studies, uncertainty was represented as intervals on phase boundaries (with respect to composition) or invariant reactions (with respect to temperature) and was unable to represent the uncertainty in eutectoid reactions or in the stability of phase regions. In this work, we propose a suite of tools that leverages samples from the multivariate model parameter distribution to represent uncertainty in forms that surpass previous limitations and are well suited to materials design. These representations include the distribution of phase diagrams and their features, as well as the dependence of phase stability and the distributions of phase fraction, composition activity and Gibbs energy on X-T-P location - irrespective of the total number of components. Most critically, the new methodology allows the material designer to interrogate a certain composition and temperature domain and get in return the probability of different phases to be stable, which can positively impact materials design