8,559 research outputs found
The First Measurement of Cassiopeia A's Forward Shock Expansion Rate
We have obtained a second epoch observation of the Cassiopeia A supernova
remnant (SNR) with the Chandra X-ray Observatory to measure detailed X-ray
proper motions for the first time. Both epoch observations are 50 ks exposures
of the ACIS-S3 chip and they are separated by 2 years. Measurements of the thin
X-ray continuum dominated filaments located around the edge of the remnant
(that are identified with the forward shock) show expansion rates from 0.02%/yr
to 0.33%/yr. Many of these filaments are therefore significantly decelerated.
Their median value of 0.21%/yr is equal to the median expansion of the bright
ring (0.21%/yr) as measured with Einstein and ROSAT. This presents a conundrum
if the motion of the bright ring is indicative of the reverse shock speed. We
have also re-evaluated the motion of the radio bright ring with emphasis on
angle-averaged emissivity profiles. Our new measurement of the expansion of the
angle-averaged radio bright ring is 0.07 plus or minus 0.03%/yr, somewhat
slower than the previous radio measurements of 0.11%/yr which were sensitive to
the motions of small-scale features. We propose that the expansion of the
small-scale bright ring features in the optical, X-ray, and radio do not
represent the expansion of the reverse shock, but rather represent a
brightness-weighted average of ejecta passing through and being decelerated by
the reverse shock. The motion of the reverse shock, itself, is then represented
by the motion of the angle-averaged emissivity profile of the radio bright
ring.Comment: accepted to Ap
Cognitive appraisal of dissertation stress among undergraduate students
The present study examined changes in primary and secondary appraisal, and coping strategies utilized in the final weeks leading to dissertation submission. Sixty volunteer Sports Studies dissertation students (male: n = 29; female: n = 31) completed an adapted Cognitive Appraisal of Health Scale (CAHS: Kessler, 1998), and Brief COPE (Carver, Scheier, & Weintraub, 1989) on 4 occasions over the 6 weeks before dissertation submission. Repeated measures multivariate analysis of variance indicated a significant main effect for gender, with no main effect for changes over time and no significant interaction effect. Results demonstrated that males perceived the dissertation to be significantly more threatening and iess challenging than females. With regard to coping, males used more active coping, positive reframing, planning, and acceptance of the stressor, with lower scores for self-blame, venting of emotions, and behavioral disengagement. The results suggest that, for this student population, the dissertation did not become increasingly stressful in the period before submission. Clear relationships were also evidenced between primary appraisal, secondary appraisal, and coping. Future research should seek to identify factors that moderate the influence of situational stressors on coping responses among undergraduate students
Still a Frightening Unknown: Achieving a Constitutional Balance between Civil Liberties and National Security during the War on Terror
Informing High School Choices: The Progress & Challenges of Small High Schools in Philadelphia
In the School District of Philadelphia in 2007-08, almost one third of high school students attend one of the district's 32 small high schools. Of these, 26 have been newly created or significantly changed since 2002. These small schools have a range of admissions criteria with two thirds being selective admission and one third neighborhood high schools. Along with this increase in high school options has been a growing interest in high school choice, with 73% of eighth graders applying to high schools outside their neighborhood in 2006. However, within the School District of Philadelphia, there is only one 'choice'-the neighborhood high school-for the 51% of rising ninth graders who try to exercise choice but are not accepted to any of their preferred choices. For those students who do attend small high schools, our research suggests that this more personalized environment is demonstrating promising outcomes with regard to improved school climate, improved interpersonal relationships between adults and students and student-to-student, and students' perceptions of their school experience. The small high school model is particularly promising for neighborhood high schools where positive relationships may help stem high dropout rates. Among our five case study high schools, the one small neighborhood high school reported great improvements in climate compared to its previous large configuration, although some lingering climate challenges remained. While positive relationships and improved climate create the conditions for learning, principals and teachers at all five case study schools reported that more was needed to develop and maintain a rigorous academic program for all students. They described the need for common faculty planning time to strengthen their academic program and more flexibility and resources to meet the unique staffing and rostering challenges of small high schools
Assessing the potential for reopening a building stone quarry : Newbigging Sandstone Quarry, Fife
Newbigging Sandstone Quarry in Fife is one of a number of former quarries in the Burntisland-
Aberdour district which exploited the pale-coloured Grange Sandstone from Lower
Carboniferous rocks. The quarry supplied building stone from the late 19th century, working
intermittently from 1914 until closure in 1937, and again when reopened in the 1970s to the
1990s. The stone was primarily used locally and to supply the nearby markets in the Scottish
Central Belt.
Historical evidence indicates that prior to sandstone extraction, the area was dominated by largescale
quarrying and mining of limestone, and substantial sandstone quarrying is likely to have
begun after the arrival of the main railway line in 1890. It is probable that removal of the
sandstone was directly associated with limestone exploitation, and that the quarried sandstone
was effectively a by-product of limestone production. Sandstone extraction was probably viable
due to the existing limestone quarry infrastructure (workforce, equipment, transportation) and the
high demand for building stone in Central Scotland in the late 19th century.
The geology within Newbigging Sandstone Quarry is dominated by thick-bedded uniform
sandstone with a wide joint spacing, well-suited for obtaining large blocks. However, a
mudstone (shale) band is likely to be present within a few metres of the principal (north) face of
the quarry, around which the sandstone bed thickness and quality is likely to decrease. The
mudstone bed forms a plane sloping at a shallow angle to the north, so that expansion of the
quarry in this direction is likely to encounter a considerable volume of poor quality stone.
Additionally, an east-west trending fault is present approximately 100 metres north of the quarry
face, which is also likely to be associated with poor quality (fractured) stone
Insight for Teacher Preparation Program Administrators: Enhancing Pre-service Educators’ Intercultural Sensitivity and Deep Proficiency in Culturally Responsive Teaching through Short-term Study Abroad
Teacher preparation program administrators face the issue of expanding curricula to prepare teacher candidates for the diverse population of students they will encounter (Trent, Kea, Oh, 2008). Globalization demands that teacher candidates grasp how to function in a more integrated and interdependent society (McGrew, 2005). According to Smith-Davis (2004) students from non-English speaking countries compose the fastest growing United States K-12 student population, and those identified as limited English proficient were over 10 million in 2004. The United States Census reported in the \u27\u27New Census Bureau Report the number of individuals five and older who speak languages other than English at home more than doubled in the past three decades (2010). If teacher preparation program leaders fail to prepare future educators with the dispositions, knowledge, and skills necessary to meet the needs of the nation\u27s school population, the national security and economic development may be hindered, and the position of the United States in the world community may be challenged (Zanh, 2011).
Teacher preparation program leaders are faced with how to strengthen teacher candidates\u27 level of intercultural sensitivity and to prepare them to implement culturally responsive pedagogy through course content and other activities (Lin, Lake, & Rice, 2008, p. 188). Integrating multicultural education throughout all courses instead of adding a stand-alone course dedicated to cultural awareness and instruction is one manner to enhance candidates\u27 level of intercultural sensitivity, and this means is supported by many researchers (Cochran-Smith, Davis, & Fries, 2004). Another way to heighten intercultural sensitivity and gain skill in delivering culturally-responsive teaching
strategies is through cross-cultural experiences (Foster, 1995; Gay, 2000; McAllister & Irving, 2002; Nieto, 2006). One such cross-cultural experience that deans, department heads, and faculty may explore is short-term study abroad. Short-term study abroad is more affordable and attractive to university students who cannot or will not commit to a semester or yearlong study abroad experience (Donnelly-Smith, 2009). As defined by Donnelly-Smith (2009), short-term study abroad experiences are those where students participate for fewer than eight weeks. These experiences have the potential of positively impacting teacher candidates\u27 intercultural sensitivity (Lawton et al., 2006). DonnellySmith stated that little formal research was displayed in the literature that described study abroad outcomes (2009).
The purpose of this paper is to reveal how a short-term study abroad experience affected teacher candidates from a Texas regional university, and thus enhanced their intercultural sensitivity and deepened their knowledge and skill in culturally-responsive teaching strategies. This study was unique from other studies presented in the literature because the focus was how another country implements early childhood education and prepares future teachers. Teacher candidates were afforded an opportunity to compare Italy\u27s early childhood education system to the system they were more familiar with in the United States
Lean towards learning: connecting Lean Thinking and human resource management in UK higher education
From its origins in the automotive industry, Lean Thinking is increasingly being seen as a solution to problems of efficiency and quality in other industries and sectors. In recent years attempts have been made to transfer Lean principles and practice to the higher education sector with indications of mixed consequences and debate over its suitability. This paper contributes to the debate by drawing evidence from thirty-four interviews conducted across two UK universities that have implemented Lean in some of their activities and we pay particular attention to the role of the HR function in facilitating its introduction. The findings suggest there are problems in understanding, communicating and transferring Lean Thinking in the higher education context; that, despite HR systems being vital facets of Lean, HR professionals are excluded from participation; and that as a consequence the depth and breadth of Lean application in the two institutions is very limited
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