Scientific reasoning abilities of non-science majors in physics-based courses

We have found that non-STEM majors taking either a conceptual physics or astronomy course at two regional comprehensive institutions score significantly lower pre-instruction on the Lawson's Classroom Test of Scientific Reasoning (LCTSR) in comparison to national average STEM majors. The majority of non-STEM students can be classified as either concrete operational or transitional reasoners in Piaget's theory of cognitive development, whereas in the STEM population formal operational reasoners are far more prevalent. In particular, non-STEM students demonstrate significant difficulty with proportional and hypothetico-deductive reasoning. Pre-scores on the LCTSR are correlated with normalized learning gains on various concept inventories. The correlation is strongest for content that can be categorized as mostly theoretical, meaning a lack of directly observable exemplars, and weakest for content categorized as mostly descriptive, where directly observable exemplars are abundant. Although the implementation of research-verified, interactive engagement pedagogy can lead to gains in content knowledge, significant gains in theoretical content (such as force and energy) are more difficult with non-STEM students. We also observe no significant gains on the LCTSR without explicit instruction in scientific reasoning patterns. These results further demonstrate that differences in student populations are important when comparing normalized gains on concept inventories, and the achievement of significant gains in scientific reasoning requires a re-evaluation of the traditional approach to physics for non-STEM students.Comment: 18 pages, 4 figures, 3 table

Matrix Completion Problems for the Positiveness and Contraction Through Graphs

In this work, we study contractive and positive real matrix completion problems which are motivated in part by studies on sparce (or dense) matrices for weighted sparse recovery problems and rating matrices with rating density in recommender systems. Matrix completions problems also have many applications in probability and statistics, chemistry, numerical analysis (e.g. optimization), electrical engineering, and geophysics. In this paper we seek to connect the contractive and positive completion property to a graph theoretic property. We then answer whether the graphs of real symmetric matrices having loops at every vertex have the contractive completion property if and only if the graph of said matrix is chordal. If this is not true, we characterize all graphs of real symmetric matrices having the contractive completion property

Religion, competition and liability: Dutch cooperative banking in crisis, 1919-1927

What accounts for the differences in the performance of cooperatively-owned banks in the Dutch financial crisis of the early 1920s? This thesis measures and explains the (relative) performance of boerenleenbanken (rural Raiffeisen banks) and middenstandsbanken (urban Schulze-Delitzsch banks) during the Netherlands' interwar banking crisis by applying various economic methods to new historical evidence. The thesis asks: (1) what were the effects on risk-taking behaviour of differences in the religious attitudes of bankers and their customers? (2) what was the relationship between interbank competition and financial stability? and (3) what was the consequence of the liability choices made by shareholders for their banks' continued survival? Using a combination of economic theory, quantitative financial analysis and qualitative business histories, this thesis finds that: (1) banks serving small religious groups were less willing, despite being more able, to take on risks than those serving majority denominations; (2) those banks that were subject to the lowest competitive pressures enjoyed the most liquid investment portfolios; and (3) the choice of liability limitation available to bankers in uenced their balance sheet risks, for the worse. Together, these findings lead to the conclusion that social, organisational and institutional factors each explain part of the heterogeneity in the fate of the Netherlands' cooperative banks during a period which includes unprecedented debt- deflationary financial turmoil: hence, (1) strict membership criteria and the use of personal guarantors in loan agreements acted as strong devices to allow banks for minorities, regardless of their denomination, to screen and monitor their customers; (2) the switching costs associated with religious affiliation resulted in a competition- stability tradeoff during periods of extreme distress; and (3) the stakeholders of the banks which failed were probably less risk-averse than those of banks which did not, the consequence of endogenous group formation by risk type

Automated SG-DBR Tunable Laser Calibration Optimized for Optical Coherence Tomography Applications

SG-DBR lasers look to solve many problems associated with present OCT sources by being cost effective, smaller in size, more robust, and by operating at faster repetition rates. Swept Source Optical Coherence Tomography (SS-OCT) requires a tunable laser source that exhibits linear frequency sweeps, large frequency spans, and high repetition rates. This work accomplishes this by using four synchronized waveforms sent to the input of a Sampled Grating-Distributed Bragg Reflector (SG-DBR) laser. Three mirrors control the wavelength, while an internal semiconductor optical amplifier controls the laser output power. In dealing with this complicated tuning mechanism, a manual sweep calibration is too time-consuming. This thesis demonstrates an efficient method for automating the calibration of tunable SG-DBR lasers by implementing a gain medium voltage sensing algorithm, as opposed to the previous inefficient manual efforts. Experimental OCT tests are also performed by utilizing a Mach-Zehnder interferometer as a device under test to verify the accuracy of the laser calibration methodology. The OCT response to a single reflection event is measured over a range of repetition rates. A method to reduce these spurious display responses caused by wavelength stitching imperfections is implemented through a self-generating optical clock

The transformation of community hospitals through the transition to value-based care: Lessons from Massachusetts

Enabling community hospitals to provide efficient and effective care and maintain competition on par with their academic medical center (AMC) counterparts remain challenges for most states. Advancing accountable care readiness adds to the complexity of these challenges. Community hospitals experience narrower operating margins and more limited access to large populations than their AMC counterparts, making the shift to value-based care difficult. Massachusetts has taken legislative action to ensure a statewide focus on reducing healthcare costs, which includes a nearly $120-million grant program supporting community hospital and system transformation toward a value-based environment. The Massachusetts Health Policy Commission’s Community Hospital Acceleration, Revitalization and Transformation (CHART) investment program is the state’s largest effort to date aimed at readying community hospitals for value-based care. In doing so, Massachusetts has created the largest state-driven, all-payer (payer-blind) readmission reduction initiative in the country. n this paper, we examine the design and evolution of CHART Phases 1 and 2 and offer insights for other states contemplating innovative approaches to bolstering community hospital participation in value-based care models

FUNDAMENTAL STUDIES OF COLLISION-ACTIVATED DISSOCIATION (CAD) OF DEPROTONATED MODEL COMPOUNDS RELEVANT TO LIGNIN DEGRADATION PRODUCTS

ABSTRAC

Developmental Potential Of Rat Myoblast Lineages

Skeletal muscle consists of multinucleated fibres which are classified as slow (I) or fast (IIA, IIB, IIX) muscle fibre types which differ in their contractile properties and their expression of contractile protein isoforms. Individual muscles contain characteristic distributions of fibre types which can be identified based on their myosin heavy chain (MyHC) content. While classical studies have demonstrated that the fibre type composition of adult muscles can be altered by extrinsic factors (such as changes in the pattern of innervation), recent studies suggest that different fibre types may be formed from distinct myoblast lineages. The purpose of this study was to test the hypothesis that myoblasts from early and late stages of development represent distinct myoblast lineages, which differ in their developmental potential. The goals of this project were to (a) determine if developmental populations of myoblasts in the rat exhibit different fibre type potentials, (b) determine when lineages are established during myogenesis, and (c) determine if extrinsic factors can modulate their expression.;To address these questions, myoblasts obtained from embryonic day (ED) 14 (embryonic) and ED20 (fetal) rat hindlimbs were grown in culture and analyzed for MyHC expression using a panel of monoclonal antibodies specific for MyHC isoforms. Embryonic myoblasts expressed both embryonic and slow MyHCs while fetal myoblasts expressed embryonic, neonatal fast and adult fast isoforms, suggesting that these populations have different default patterns of expression and may be programmed to form slow or fast fibre types, respectively. To determine if these two populations could fuse with each other and if fusion altered MyHC expression, individual populations were specifically labelled and then co-cultured. Examination of these co-cultures revealed muscle heterokaryons containing nuclei from both embryonic and fetal myoblast populations. Individual nuclei maintained their characteristic MyHC expression as nuclear domains within these muscle heterokaryons indicating that distinct developmental potentials are established prior to fusion.;To determine if external cues could affect the developmental potential of these myoblast populations, both embryonic and fetal myoblasts were injected in the caudate-putamen of adult rats. Myotubes expressing slow, IIA, IIB and IIX MyHCs were observed in both types of injection grafts. However, myotubes which expressed exclusively slow MyHC were only found in the embryonic injection sites, indicating the existence of a slow only myoblast population only at early time points in development. Therefore, it appears that fetal myogenic precursor cells are present in embryonic cultures, but only differentiate in vivo.;These studies support the existence of myoblast lineages and suggest that, although environmental cues can modulate fibre type expression, the intrinsic program of the myogenic lineage determines the extent of modulation that can occur. This restriction in developmental potential represents the adaptive range of a myoblast lineage. The delineation of muscle precursor cells with different developmental potentials follows myogenic determination and precedes myogenic differentiation. (Abstract shortened by UMI.