3,461 research outputs found
Stimulated resonant inelastic x-ray scattering with chirped, broadband pulses
We present an approach for initiating and tracing ultra-fast electron
dynamics in core-excited atoms, molecules and solids. The approach is based on
stimulated resonant inelastic x-ray scattering induced by a single, chirped,
broadband XUV/x-ray pulse. A first interaction with this pulse prepares a
core-excited state wave packet by resonant core-excitation. A second
interaction with the pulse at a later time induces the transition to
valence-excited states which is associated with stimulated emission. The
preparation of the core-excited wave packet and the transition from the
core-excited states to the valence-excited states occur at distinct
chirp-dependent times. As a consequence, the stimulated emission carries
information about the time evolution of the core-excited state wave packet
Local, Regional, or Global Asset Pricing?
Analyzing several developed and emerging international markets, I test the ability of global, regional, and local models to explain a large set of 134 cross-sectional anomalies. My main finding is that both global and regional factor models create substantially larger average absolute alphas than local factor models. Annual (absolute) anomaly portfolio alphas are on average 1.7 and 1.1 percentage points higher, respectively, with global and regional than with local factor models. Even for the most recent period, there is no evidence of a catch-up of global and regional factor models. There is substantial potential for international diversification of anomaly strategies
Development of Ultra High Performance Composite Impact Panels Using EMAA
UHPC with the addition of fibers is recognized for its increased impact resistance compared to typical strength concrete. To further increase the resilience, recent studies have been conducted to reinforce the UHPC with CFRTP on the front and rear face to create sandwich panels. These studies used PETg/E-glass CFRTP bonded to the UHPC using EMAA (Surlyn) in a stamp thermoforming process. Impact tests conducted on these panels have shown that delamination has been the initial and detrimental failure to the sandwich composite. Increasing the composites resistance to debonding will increase the impact energy required to debond the composite. In this study the bond capability of EMAA (Surlyn) was investigated in an attempt to increase the bond strength and improve the composite sandwich panels impact resilience. Single lap shear and CFRTP reinforced beam bending tests were conducted to investigate the bond of the EMAA to the CFRTP and UHPC respectively. The different glass transition temperatures of EMAA and PETg proved to cause the complication of bubbling in the EMAA between the PETg and UHPC. In an attempt to remove the need for PETg, trials were conducted to create a new CFRTP using CSM E-glass fibers and EMAA matrix. This new CFRTP was created and was able to successfully bond to the UHPC core to create a new Surlyn CSM impact panel. Impact tests of 50 J were i conducted on the two thermoplastic panels and two other panels fabricated using a two-part epoxy and a Urethane adhesive with the PETg CFRTP. The compliance was found before and after impact to measure the damage due to impact. The two-part epoxy and Surlyn CSM panel experienced the lowest amount of damage. However, the Surlyn CSM panel dissipated the least amount of energy due to impact.The original CFRTP/Surlyn Composite panel absorbed the most energy from the impact while presenting the most damage due to major delamination of the panel. The Surlyn CSM panel provided the lowest deflection during impact and the least amount of calculated and visualized damage
Variations in surface and thermocline conditions of the Western Pacific Warm Pool : Insights from Mg/Ca and stable isotopes in foraminifera tests
The Western Pacific Warm Pool (WPWP) is a major source of heat and moisture to the global atmosphere and thus plays a major role in the global climate system. This thesis deals with the reconstruction of past variations in WPWP surface and thermocline conditions with the overarching goal to better understand the regional ocean and climate variability over the last (two) glaciala interglacial cycle(s). The reconstruction is mainly based on records of stable oxygen isotopes (I 18O) and Mg/Ca in planktic foraminifera from marine sediment cores. First, the proxies are calibrated against modern water column data. Then, these calibrations are applied to records from the southern WPWP off Papua New Guinea. The records illustrate the interplay of local and remote forcing on the WPWP on glacial-interglacial and orbital timescales by indicating that (I) variations in the Pacific Walker circulation affect the WPWP on glacial-interglacial timescales, (II) climate variations in the extratropics influence the WPWP thermocline in response to astronomical forcing and (III) precession is the main driver for precipitation over the WPWP
“Empirical Asset Pricing” by Wayne Ferson
[no abstract available
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Planning decision for vacant lots in the context of shrinking cities : a survey and comparison of practices in the United States
textPlanning theory and practice in the United States has been dominated by a paradigm of growth; however, since the 1980s, many cities have faced prolonged population decline, prompting questions about how shrinkage is engaged as planners attempt to provide for health, safety, and welfare. This investigation surveys and compares lines of thought being used to make decisions regarding these properties, with particular emphasis on planners located within cities having dissimilar experiences of “shrinking.” Principally, it is focused on vacant and abandoned lots, which are the most immediately visible symptom of population decline and offer the greatest opportunity to reimagine urban form-and-function relationships. The investigation begins with a literature review of the causes and effects of shrinking as well as an investigation into historical research and contemporary thought on vacant land in the United States. Current reasoning supporting decisions about vacant and abandoned lots is identified through a national survey of planning professionals in fifteen cities with either stable-to-growing or shrinking populations. These are augmented by selected follow-up interviews. Both stratified sampling and matching were used to achieve a range of city characteristics and control for them across growth orientation. This approach is new in that while case studies of one or two shrinking cities have been undertaken, there has not been a national survey focused on shrinking cities and vacancy. The goal is to understand regional trends, tools, and obstacles to progress. The results indicate a range in which methods and techniques predicated on the dominant and normative growth paradigm have been both adopted or adapted for use in shrinking cities. Results suggest that concepts regarding quality of life, intentions for the future, and community goals have been reprioritized and redefined in shrinking cities. Finally, results indicate ways in which ideas regarding the built environment and the discontinuities of the urban fabric are being reconceptualized in the face of massive economic and demographic upheaval.Community and Regional Plannin
Social Studies in South Korea: Examining Teacher and Teacher Educator’s Views
The Republic of South Korea is a nation that has seen dramatic changes in its economic and educational systems over the course of the last 50 years. These circumstances present unique views of citizenship and the roles that teachers and teacher educators play in this process. This study presents two case studies, one a classroom teacher and the other a teacher educator. It examines their views of social studies and geography education, the process training new citizens, and offers insights into what the dynamic relationship between the two offers future educators and teacher educators.
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