Semiclassical theory for small displacements

Characteristic functions contain complete information about all the moments of a classical distribution and the same holds for the Fourier transform of the Wigner function: a quantum characteristic function, or the chord function. However, knowledge of a finite number of moments does not allow for accurate determination of the chord function. For pure states this provides the overlap of the state with all its possible rigid translations (or displacements). We here present a semiclassical approximation of the chord function for large Bohr-quantized states, which is accurate right up to a caustic, beyond which the chord function becomes evanescent. It is verified to pick out blind spots, which are displacements for zero overlaps. These occur even for translations within a Planck area of the origin. We derive a simple approximation for the closest blind spots, depending on the Schroedinger covariance matrix, which is verified for Bohr-quantized states.Comment: 16 pages, 4 figures

Are stealth scalar fields stable?

Non-gravitating (stealth) scalar fields associated with Minkowski space in scalar-tensor gravity are examined. Analytical solutions for both non-minimally coupled scalar field theory and for Brans-Dicke gravity are studied and their stability with respect to tensor perturbations is assessed using a covariant and gauge-invariant formalism developed for alternative gravity. For Brans-Dicke solutions, the stability with respect to homogeneous perturbations is also studied. There are regions of parameter space corresponding to stability and other regions corresponding to instability.Comment: 10 pages, 1 table, no figures, to appear in Phys. Rev,

Preservice Teachers\u27 Perceptions of the Influence and Value of an Embedded, School-Based Field Experience

This study explored how preservice teachers perceive the influence and value of an embedded, school-based field experience. Information was gathered from preservice teachers using surveys and a focus group interview. The data collected showed that an embedded field experience tied to a language arts methods course was generally a positive influence leading to great self-efficacy. Further, the data compared similarly to research supporting the notion that embedded field experiences generally have the effect of strengthening preservice teachers’ self-efficacy. Looking at Bandura’s work in Self-efficacy: Toward a unifying theory of behavioral change, it shows that early interactions and successes will boost the self-efficacy of preservice teachers. This study found that successful experiences help preservice teachers value their embedded, school-based field experiences and help view it as something positive. Even if the experience had its difficulties, preservice teachers were able to learn from the situation and if they ever find themselves in a similar circumstance, they will feel more confident about handling things. Therefore, when these preservice teachers become in-service teachers, they will feel more confident about their abilities compared to in-service teachers who did not have similar experiences in their teacher preparation program

Use of an artificial miniaturized enzyme in hydrogen peroxide detection by chemiluminescence

Advanced oxidation processes represent a viable alternative in water reclamation for potable reuse. Sensing methods of hydrogen peroxide are, therefore, needed to test both process progress and final quality of the produced water. Several bio-based assays have been developed so far, mainly relying on peroxidase enzymes, which have the advantage of being fast, efficient, reusable, and environmentally safe. However, their production/purification and, most of all, batch-to-batch consistency may inherently prevent their standardization. Here, we provide evidence that a synthetic de novo miniaturized designed heme-enzyme, namely Mimochrome VI*a, can be proficiently used in hydrogen peroxide assays. Furthermore, a fast and automated assay has been developed by using a lab-bench microplate reader. Under the best working conditions, the assay showed a linear response in the 10.0–120 µM range, together with a second linearity range between 120 and 500 µM for higher hydrogen peroxide concentrations. The detection limit was 4.6 µM and quantitation limits for the two datasets were 15.5 and 186 µM, respectively. In perspective, Mimochrome VI*a could be used as an active biological sensing unit in different sensor configurations

Useful thecniques to improve student's abilities to read in english : a study conduted with third grade students in the Oxforf School, Santiago.

Chapter 1 Statement of the Problem, Justification, Significance, Research Question, Definition of Key Terms, Chapter II Review of the Literature, Chapter III Methodology Procedure, Statistic Analysis, Sample, Chapter IV Observations, Firidings, Statistic Results, Conclusion, Recommendations, Bibliography