Regular modes of a mixed dynamical based optical fiber

A multimode optical fiber with a truncated transverse cross section acts as a powerful versatile support to investigate the wave features of complex ray dynamics. In this paper, we concentrate on the case of a geometry inducing a mixed dynamics. We highlight the properties of regular modes associated to stable periodic orbits such as an enhanced intensity localization and report unexpected attributes such as the statistics of the Inverse Participation Ratio that present features analogous to those of Anderson localized modes. Our study is supported by both numerical and experimental results.Comment: 12 pages, 13 figure

A grid search optimization subroutine for use with the GOSPEL optimization software package

Grid search optimization subroutine for analyses on distributed lumped activity network

Representing science education in UK newspapers : a case study on the controversy surrounding teaching the theory of evolution and creationism in science classes

The thesis examines representations of science education in UK newspapers and focuses on the role of expert sources in a controversy about the teaching of creationism alongside the theory of evolution in science classrooms. The newspaper reporting revolved around the City Technology College Emmanuel College in Gateshead, mainly in Spring 2002. The empirical research focused on two connected media elements: newspaper content and newspaper production. A quantitative and qualitative approach to analysing media content examined 287 newspaper articles from 20 UK newspapers, from I January 2002 to 20 February 2004, inclusive. The production analysis was based on semi-structured interviews with media professionals. The analysis of media content shows that the debate around Emmanuel College consisted of several related controversial issues. A range of expert sources were quoted in the articles, using various argumentation lines to address the issues of the controversy. The way expert sources were described by the journalists mainly seemed to enhance the credibility of those supporting the scientific consensus. Further analysis shows that some experts formed heterogeneousc oalitions of experts calling for action. Collaborative networks of experts appeared as efforts to enhance credibility and gain access to the media. The evidence presented in this thesis points to the importance of understanding expertise not only in individual but also in collective terms and to investigate expertise in terms of the argumentation lines reported. The analysis of semistructured interviews with media professionals demonstrates that the specialism of correspondents (e. g. on covering science or education) could influence which expert sources were selected, how they were represented and whether newspaper accounts were balanced or not. This influenced how reports were framed. Overall, the thesis demonstrates a more complex conceptualisation of expertise, one where experts are mobilised to conduct boundary work in key sites: media reporting and the National Curriculum for Science

The Impact of Mentoring At-risk Youth on the Socialization Process of Pre-Service Teachers

While much is known about how traditional field based practical experiences in teacher preparation programs impact the socialization of pre-service teachers, less is known about how practical experiences within after-school programs and other contexts influence pre-service teacher socialization. Relatedly, many scholars have sought to understand at-risk youth and have investigated teachers’ experiences with these students within the context of schools and the gym. The purpose of this study was to understand how mentoring at-risk youth in an after-school program impacted the socialization of six pre-service teachers. Occupational Socialization Theory provided the theoretical framework for this study. Six PETE majors, in their first year of the PETE program participated in the study which occurred concurrently with their involvement in the after-school program. Data sources included four semi-structured interviews with each participant and four critical incident accounts. Findings indicated that the PSTs described three important outcomes resulting from working as mentors to at-risk youth in the after-school program. First, PSTs discussed the significance of having additional practical experience teaching and how this furthered their teacher development. PSTs also described an impassioned appreciation for knowing students. Finally, as a result of mentoring at-risk children, PSTs felt an overwhelming personal responsibility to demonstrate healthy social and emotional behaviors. This provides further insights into the degree to which pre-service teachers are active agents in constructing their own conceptions of teaching through the dialectical nature of socialization. The experiences and knowledge gained by the pre-service teachers in this study served to construct a view of teaching that includes a strong emphasis on knowledge of students and focus on affective skill development. Consistent with previous literature, the importance of practical experiences to pre-service teachers like the one in this study may facilitate pre-service teachers in moving toward a focus on students earlier in teacher training programs

A Criterion of Driving Ability

In the field of highway safety considerable work has been done to develop various tests of driving ability. In this development two major problems present themselves. First, the test itself must be perfected so as to be reliable, that is, the test must give the same result when repeated. Second, the validity of the test must be determined by comparing the results of the test with actual performance. To do this a criterion of driving ability must be established. Rating of drivers from general observation does not yield satisfactory results. As an instance of this the correlation between accidents per year and a typical rating was found to be +.01 for a group of 43 bus drivers

Spectral properties of microwave graphs with local absorption

The influence of absorption on the spectra of microwave graphs has been studied experimentally. The microwave networks were made up of coaxial cables and T junctions. First, absorption was introduced by attaching a 50 Ohm load to an additional vertex for graphs with and without time-reversal symmetry. The resulting level-spacing distributions were compared with a generalization of the Wigner surmise in the presence of open channels proposed recently by Poli et al. [Phys. Rev. Lett. 108, 174101 (2012)]. Good agreement was found using an effective coupling parameter. Second, absorption was introduced along one individual bond via a variable microwave attenuator, and the influence of absorption on the length spectrum was studied. The peak heights in the length spectra corresponding to orbits avoiding the absorber were found to be independent of the attenuation, whereas, the heights of the peaks belonging to orbits passing the absorber once or twice showed the expected decrease with increasing attenuation.Comment: 7 pages, 7 figure