An Analysis of Teachers’ Perceptions of Classroom Management

The purpose of this study was twofold: (1) to compile data supplied by educators of the Tacoma Public School District who responded to questionnaires designed to report information related to classroom management; and (2) to analyze the above mentioned data in an effort to determine how beginning teachers perceive classroom management practices and procedures, and to note changes of practice during initial teaching experiences

Laser diffraction particle sizing: Instrument probe volume relocation and elongation

The effective probe volume of laser diffraction particle sizing instruments depends on many instrument parameters. In particular the probe volume axial boundaries and its location along laser beam are essentially defined by the onset of a vignetting effect where light scattered at large angles from small particles misses the transform lens. This vignetting effect results in a probe volume that must be inconveniently close to the lens in order to detect smaller diameter particles (less than 100 micrometers). With the addition of an appropriately designed Keplerian telescope, the probe volume may be relocated and elongated. The theory of operation of this supplemental optical system is described. Design considerations for these supplemental optical systems are described, including recommendations for lens specifications, assembly and use. An image transfer system is described which has been designed for use on a Malvern 2600HSD instrument. Experimental validation of this image transfer system is described

Decay of Intensity of Certain Hg Lines in an Hg-Ar Discharge

The afterglow of four mercury spectral lines was examined in a mercury-argon electric discharge. The 2537- Å line decays in a complex fashion with three definite modes of decay. The 4077-, 4358-, and 5461- Å lines exhibited an even more complicated decay. These lines exhibited an initial rapid decay followed by an increase in intensity. Finally the intensity of these lines went through two maxima before they decayed in intensity at a slow constant rate. The actual intensity behavior of the 2537- Å line was masked by the imprisonment of resonance radiation. It is postulated that the main processes governing the initial decay were spontaneous radiative decay coupled with electron and ion repopulation of the excited mercury states. The negative decay constant occurring around 100 μsec was probably controlled by the group action of the following processes: ionization of mercury by argon and the resultant recombination, thermalization of discharge electrons and their resultant recombination, and production of electrons by the -interaction of mercury metastable atoms and their recombination. The final slow rate of decay was probably controlled by mercury molecular dissociative recombination

The Contrasting Effects of an Action Video Game on Visuo-Spatial Processing and Proactive Cognitive Control

First person shooter or action video games represent one of the most popular genres within the gaming industry. Studies reveal that action gaming experience leads to enhancements of visuo-spatial processing. In contrast, some correlational evidence reveals that experience with action video games may be associated with reduced proactive cognitive control. The two primary goals of the current study were to test the causal nature of the effect of action gaming on proactive cognitive control and to examine whether an increase in visuo-spatial processing and a decrease in proactive cognitive control arise from the same amount of experience playing an action video game. Participants completed tasks measuring visuo-spatial processing and cognitive control before and after 10 practice sessions involving one of three video games or were assigned to a no gaming experience control group. The data revealed the typical increase in visuo-spatial processing and a decrease in proactive, but not reactive, cognitive control following action game training. The sizes of these two training effects were similar in magnitude, but interpretation of the effects was constrained by baseline differences between the four groups of subjects. The possibility of a causal effect of action gaming on proactive cognitive control is interesting within the context of correlational evidence linking greater action gaming experience to reduced cognitive control, poor decision making, and increased impulsivity

TEXAS AGRICULTURE BY CONGRESSIONAL DISTRICT: 1993-1996

Texas Agriculture by Congressional Districts: 1993-96 is an update of previous editions of this publication. Commodity sales by county are estimates made by county agents and, therefore, are not official. In all but 4 of 30 Texas congressional districts, production agriculture accounts for over $100 million in sales. In 18 of the districts, farm program commodities represent over$50 million in sales.Production Economics,

Parkinson\u27s Disease, Amantadine Hydrochloride Therapy and Dopa Metabolites

In an attempt to clarify the effect of amantadine hydrochloride therapy in Parkinson\u27s disease, dopa metabolites were measured in the urine of 15 patients who were taking this medication. The results indicated that patients on amantadine therapy had lower urinary levels of epinephrine plus norepinephrine than either normal individuals or parkinsonian patients not receiving amantadine. Patients who developed livedo reticularis during amantadine therapy showed a small but significant increase in urinary dopamine levels and a similar decrease in dopac levels, when compared to other patients on amantadine who did not develop livedo reticularis

Quantum Cosmological Relational Model of Shape and Scale in 1-d

Relational particle models are useful toy models for quantum cosmology and the problem of time in quantum general relativity. This paper shows how to extend existing work on concrete examples of relational particle models in 1-d to include a notion of scale. This is useful as regards forming a tight analogy with quantum cosmology and the emergent semiclassical time and hidden time approaches to the problem of time. This paper shows furthermore that the correspondence between relational particle models and classical and quantum cosmology can be strengthened using judicious choices of the mechanical potential. This gives relational particle mechanics models with analogues of spatial curvature, cosmological constant, dust and radiation terms. A number of these models are then tractable at the quantum level. These models can be used to study important issues 1) in canonical quantum gravity: the problem of time, the semiclassical approach to it and timeless approaches to it (such as the naive Schrodinger interpretation and records theory). 2) In quantum cosmology, such as in the investigation of uniform states, robustness, and the qualitative understanding of the origin of structure formation.Comment: References and some more motivation adde

Triangleland. I. Classical dynamics with exchange of relative angular momentum

In Euclidean relational particle mechanics, only relative times, relative angles and relative separations are meaningful. Barbour--Bertotti (1982) theory is of this form and can be viewed as a recovery of (a portion of) Newtonian mechanics from relational premises. This is of interest in the absolute versus relative motion debate and also shares a number of features with the geometrodynamical formulation of general relativity, making it suitable for some modelling of the problem of time in quantum gravity. I also study similarity relational particle mechanics (`dynamics of pure shape'), in which only relative times, relative angles and {\sl ratios of} relative separations are meaningful. This I consider firstly as it is simpler, particularly in 1 and 2 d, for which the configuration space geometry turns out to be well-known, e.g. S^2 for the `triangleland' (3-particle) case that I consider in detail. Secondly, the similarity model occurs as a sub-model within the Euclidean model: that admits a shape--scale split. For harmonic oscillator like potentials, similarity triangleland model turns out to have the same mathematics as a family of rigid rotor problems, while the Euclidean case turns out to have parallels with the Kepler--Coulomb problem in spherical and parabolic coordinates. Previous work on relational mechanics covered cases where the constituent subsystems do not exchange relative angular momentum, which is a simplifying (but in some ways undesirable) feature paralleling centrality in ordinary mechanics. In this paper I lift this restriction. In each case I reduce the relational problem to a standard one, thus obtain various exact, asymptotic and numerical solutions, and then recast these into the original mechanical variables for physical interpretation.Comment: Journal Reference added, minor updates to References and Figure

New interpretation of variational principles for gauge theories. I. Cyclic coordinate alternative to ADM split

I show how there is an ambiguity in how one treats auxiliary variables in gauge theories including general relativity cast as 3 + 1 geometrodynamics. Auxiliary variables may be treated pre-variationally as multiplier coordinates or as the velocities corresponding to cyclic coordinates. The latter treatment works through the physical meaninglessness of auxiliary variables' values applying also to the end points (or end spatial hypersurfaces) of the variation, so that these are free rather than fixed. [This is also known as variation with natural boundary conditions.] Further principles of dynamics workings such as Routhian reduction and the Dirac procedure are shown to have parallel counterparts for this new formalism. One advantage of the new scheme is that the corresponding actions are more manifestly relational. While the electric potential is usually regarded as a multiplier coordinate and Arnowitt, Deser and Misner have regarded the lapse and shift likewise, this paper's scheme considers new {\it flux}, {\it instant} and {\it grid} variables whose corresponding velocities are, respectively, the abovementioned previously used variables. This paper's way of thinking about gauge theory furthermore admits interesting generalizations, which shall be provided in a second paper.Comment: 11 page