P wave velocity variations in the Coso Region, California, derived from local earthquake travel times

Inversion of 4036 P wave travel time residuals from 429 local earthquakes using a tomographic scheme provides information about three-dimensional upper crustal velocity variations in the Indian Wells Valley-Coso region of southeastern California. The residuals are calculated relative to a Coso-specific velocity model, corrected for station elevation, weighted, and back-projected along their ray paths through models defined with layers of blocks. Slowness variations in the surface layer reflect local geology, including slow velocities for the sedimentary basins of Indian Wells and Rose valleys and relatively fast velocities for the Sierra Nevada and Argus Mountains. In the depth range of 3–5 km the inversion images an area of reduced compressional velocity in western and northern Indian Wells Valley but finds no major velocity variations beneath the Coso volcanic field to the north. These results are consistent with a recent study of anomalous shear wave attenuation in the Coso region. Between 5 and 10 km depth, low-velocity areas (7% slow) appear at the southern end of the Coso volcanics, reaching east to the Coso Basin. Numerical tests of the inversion's resolution and sensitivity to noise indicate that these major anomalies are significant and well-resolved, while other apparent velocity variations in poorly sampled areas are probably artifacts. The seismic data alone are not sufficient to uniquely characterize the physical state of these low-velocity regions. Because of the Coso region's history of Pleistocene bimodal volcanism, high heat flow, geothermal activity, geodetic deformation, and seismic activity, one possibility is to link the zones of decreased P velocity to contemporary magmatic activity

Evaluation of Evidence-Based Practices in Online Learning: A Meta-Analysis and Review of Online Learning Studies

A systematic search of the research literature from 1996 through July 2008 identified more than a thousand empirical studies of online learning. Analysts screened these studies to find those that (a) contrasted an online to a face-to-face condition, (b) measured student learning outcomes, (c) used a rigorous research design, and (d) provided adequate information to calculate an effect size. As a result of this screening, 51 independent effects were identified that could be subjected to meta-analysis. The meta-analysis found that, on average, students in online learning conditions performed better than those receiving face-to-face instruction. The difference between student outcomes for online and face-to-face classes—measured as the difference between treatment and control means, divided by the pooled standard deviation—was larger in those studies contrasting conditions that blended elements of online and face-to-face instruction with conditions taught entirely face-to-face. Analysts noted that these blended conditions often included additional learning time and instructional elements not received by students in control conditions. This finding suggests that the positive effects associated with blended learning should not be attributed to the media, per se. An unexpected finding was the small number of rigorous published studies contrasting online and face-to-face learning conditions for K–12 students. In light of this small corpus, caution is required in generalizing to the K–12 population because the results are derived for the most part from studies in other settings (e.g., medical training, higher education)

A Tale of Two Cycles: Co-Fluctuations Between UK Regions and the Euro Zone

We examine the patterns and determinants of business-cycle correlations among eleven UK regions and six euro-zone countries over the 1966-1997 period, using GMM to allow for sampling error in comparing estimated correlations. The British business cycle is found to be persistently out of phase with that of the main euro-zone economies, and the trend is towards lower correlations. We detect only minor cyclical heterogeneity among UK regions. Differences in sectoral specialisation drive some of the asymmetry in GDP fluctuations, but they do not appear significant in explaining the observed reduction in UK-EU business-cycle correlations over time.business cycles; co-fluctuations; UK regions; European monetary union; optimum currency areas

The effect of prior upper body exercise on subsequent wingate performance

It has been reported previously that the upper body musculature is continually active during high intensity cycle ergometry. The aim of this study was to examine the effects of prior upper body exercise on subsequent Wingate (WAnT) performance. Eleven recreationally active males (20.8 ± 2.2 yrs; 77.7 ± 12.0 kg;  1.79 ± 0.04 m) completed two trials in a randomised order. In one trial participants completed 2 × 30 s WAnT tests (WAnT1 and WAnT2) with a 6 min recovery period; in the other trial, this protocol was preceded with 4 sets of biceps curls to induce localised arm fatigue. Prior upper body exercise was found to have a statistically significant detrimental effect on peak power output (PPO) during WAnT1 (P < 0.05) but no effect was observed for mean power output (MPO) (P > 0.05). Handgrip (HG) strength was also found to be significantly lower following the upper body exercise. These results demonstrate that the upper body  is meaningfully involved in the generation of leg power during intense cycling

Linking appearance to neural activity through the study of the perception of lightness in naturalistic contexts

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The present paper deals with the classical question how a psychological experience, in this case apparent lightness, is linked by intervening neural processing to physical variables. We address two methodological issues: (a) how does one know the appropriate physical variable (what is the right x ?) to look at, and (b) how can behavioral measurements be used to probe the internal transformation that leads to psychological experience. We measured so-called lightness transfer functions (LTFs), that is the functions that describe the mapping between retinal luminance and perceived lightness for naturalistic checkerboard stimuli. The LTFs were measured for different illumination situations: plain view, a cast shadow, and an intervening transparent medium. Observers adjusted the luminance of a comparison patch such that it had the same lightness as each of the test patches. When the data were plotted in luminance–luminance space, we found qualitative differences between mapping functions in different contexts. These differences were greatly diminished when the data were plotted in terms of contrast. On contrast–contrast coordinates, the data were compatible with a single linear generative model. This result is an indication that, for the naturalistic scenes used here, lightness perception depends mostly on local contrast. We further discuss that, in addition to the mean adjustments, one may fi nd it useful to consider also the variability of an observer’s adjustments in order to infer the true luminance-to-lightness mapping function.DFG, MA5127/1-1, Die Bestimmung der Beziehung zwischen subjektiver Empfindung und Diskriminationsvermögen durch eine Kombination aus Psychophysik, Computationaler Modellierung und der Messung neuronaler Antworte

A transformação pessoal e política: dois estudos de caso de um estágio universitário do aprendizagem-serviço internacional

This article presents the results of two related studies that were interested in exploring the impact of international service learning (ISL) experiences on university student interns in terms of personal and political transformation. We report on the findings related to the question: “How do university students envision social change, and experience personal and political transformation following a long-term international service learning internship?” We begin by providing a background context for the studies, followed by a review of the theoretical framework, transformational learning theory, within which the studies were situated. This is followed by an overview of the research methods used to carry out this study, the findings and our analysis of the data. These were mixed methods studies using three data sources: survey questionnaires, interviews, and student blogs. Our studies demonstrate that while there is clear evidence of envisioning, personal and political transformation amongst the students who participated in this ISL internships, their experiences and the degrees of transformation varied. Our research points to the need for structured activities related to critical reflection to be built into all stages of ISL program planning, from pre-departure throughout and after the internship.En este artículo se presentan los resultados de dos estudios relacionados que estuvieron orientados a explorar el impacto de las experiencias del Aprendizaje-Servicio Internacional (ASI), en términos de transformación personal y política, en estudiantes universitarios que hicieron la pasantía. Este reporte es acerca de los hallazgos encontrados en relación a la siguiente pregunta: “Cómo conciben los estudiantes universitarios el cambio social, y cómo experiencian su transformación personal y política durante una pasantía de largo plazo del aprendizaje-servicio internacional?” Comenzamos ofreciendo un contexto de fondo para los estudios de caso, seguido de una revisión del marco teórico, la teoría de aprendizaje transformacional, en los cuales estaban situado los estudios. Esto es seguido por una revisión general de los métodos de investigación usados para llevar a cabo este estudio, los hallazgos, y nuestro análisis de los datos. Estos fueron estudios de métodos mixtos con tres fuentes de datos: cuestionarios de encuestas, entrevistas y blogs de los estudiantes. Nuestros estudios demuestran que si bien existe una clara evidencia de la conceptualización, y de la transformación personal y política de los estudiantes que participaron en esta pasantía del ASI, sus experiencias y sus grados de transformación variaron. Nuestra investigación señala la necesidad de actividades estructuradas relacionadas con una reflexión crítica para ser construida en todas las etapas de la planificación del programa del ASI antes de salir, durante, y después de la pasantía.Neste artigo apresentam-se os resultados de dois estudos relacionados que estiveram orientados a explorar o impacto das experiências do Aprendizagem-Serviço Internacional (ASI) em termos de transformação pessoal e política em estudantes universitários que realizaram o estágio. Este escrito é acerca das descobertas encontradas em relação à seguinte pregunta: “Como concebem os estudantes universitários a transformação social, e como experenciam sua transformação pessoal e política durante um estágio de larga duração do aprendizagem-serviço internacional?” Começamos oferecendo um contexto de fundo para os estudos de caso, seguido de uma revisão do marco teórico, a teoria de aprendizagem transformacional, na qual estavam situados os estudos. Isto é seguido por uma revisão geral dos métodos de investigação usados para realizar este estudo, os achados e nossas análises dos dados. Estes estudos foram de métodos mistos com três fontes de dados: questionários de opinião, entrevistas, e blogs dos estudantes. Nossos estudos demonstram que ainda que exista una clara evidência da conceptualização e da transformação pessoal e política dos estudantes que participaram neste estágio do ASI, suas experiências e seus graus de transformação variaram. Nossa investigação assinala a necessidade de atividades estruturadas relacionadas com uma reflexão crítica para ser construída em todas as etapas de planificação do programa do ASI antes de sair, durante, e depois do estágio