94 research outputs found
Upper cervical cord atrophy is independent of cervical cord lesion volume in early multiple sclerosis: A two-year longitudinal study
Background: Upper cervical cord atrophy and lesions have been shown to be associated with disease and disability progression already in early relapsing-remitting multiple sclerosis (RRMS). However, their longitudinal relationship remains unclear.
Objective: To investigate the cross-sectional and longitudinal relation between focal T2 cervical cord lesion volume (CCLV) and regional and global mean upper cervical cord area (UCCA), and their relations with disability.
Methods: Over a two-year interval, subjects with RRMS (n = 36) and healthy controls (HC, n = 16) underwent annual clinical and MRI examinations. UCCA and CCLV were obtained from C1 through C4 level. Linear mixed model analysis was performed to investigate the relation between UCCA, CCLV, and disability over time.
Results: UCCA at baseline was significantly lower in RRMS subjects compared to HCs (p = 0.003), but did not decrease faster over time (p ā„ 0.144). UCCA and CCLV were independent of each other at any of the time points or cervical levels, and over time. Lower baseline UCCA, but not CCLV, was related to worsening of both upper and lower extremities function over time. Conclusion: UCCA and CCLV are independent from each other, both cross-sectionally and longitudinally, in early MS. Lower UCCA, but not CCLV, was related to increasing disability over time
Work in Progress: Rigorously Assessing the Anecdotal Evidence of Increased Student Persistence in an Active, Blended, and Collaborative Mechanical Engineering Environment
This work in progress describes an ongoing study of an active, blended, and collaborative (ABC) course environment used in a core mechanical engineering course. This course has built on the growing body of literature citing active learning (Freeman et al., 2014), blended structures (Bowen & Ithaka, 2012), and collaborative engagement (Jeong & Chi, 2007) as positive influences on college and university science, technology, engineering, and math (STEM) outcomes. For the last six years, āDynamicsā, a core mechanical engineering course at a large public university, has utilized in-class activities, frequently-watched problem-solving videos, and a collaborative blog space to realize an ABC environment.
On one key metric of course success, the rate of students who drop, fail, or withdraw from (DFW), the course has experienced near-constant improvements since the ABC structures were introduced. In this study, the authors utilize rigorous longitudinal methods to determine whether this drop in DFW rates can be directly attributed to increased implementation of ABC features. The authors hypothesize that as instructors become accustomed to the ABC environment and increase the level of in-class activity, use of blended resources, and collaboration, the likelihood of DFW in each subsequent year would drop. However, in the same time period, each subsequent class entered with higher levels of performance on proxy measures for prior knowledge.
We therefore build a logistic regression model to predict individual-level DFW and determine whether the anecdotal drops in DFW that we observe can be attributed to the expansion of the ABC environment. More specifically, we predict likelihood of DFW based on studentsā prior knowledge (grade in the preceding course, SAT math score), key demographics (gender, race/ethnicity), the semester and year they took Dynamics, their instructor, their year in school, and their major. We test for year fixed effects {year_t, t = 1, 2, ..., 7} to determine whether odds ratios for DFW consistently and significantly decrease over time. We also test for instructor effects, in particular for differences between the instructors who were involved in the design and development of the ABC environment and more independent instructors who only partially implemented the ABC course components. We anticipate results that will provide more rigorous, less biased, and efficient estimates for the individual- and class-level components that explain variance in DFW rates. These results would provide immediate implications for the next phase of our work, as we assess the next on-term implementation of the course in 2016. Our findings would also have long-term significance for other classes in mechanical engineering and related disciplines and for classes at other institutions that are considering implementing a comprehensive ABC learning environment
Transforming a Dynamics Course to an Active, Blended, and Collaborative Format: Focus on the Faculty
Mechanical engineering programs are increasingly applying educational research by transforming courses to be more interactive and to use a blend of online and face-to-face materials. However, the process of an existing course adopting these new practices is not well studied, and even less is understood about the faculty experience from on-boarding to delivery of a new curriculum or pedagogy. In this study, we follow the translation of an active, blended, and collaborative (ABC) curriculum for a core dynamics course from a large public university (where the ABC curriculum was developed) to a small private university. We use interpretive phenomenology to focus on the lived experience of the instructor newly implementing these course materials, format, and pedagogical approach. Specifically, we address the following research questions: (1) What is the lived experience of a mechanical engineering instructor at a different institution as she adopts and adapts the provided materials and format? (2) How does the experience of this instructor evolve throughout the semester? We use rich qualitative data to understand the experience of the instructor, who taught this course in its prior format and, in Fall 2015, taught the āoff-termā core dynamics course via the new ABC structure. Through weekly reflection prompts, pre- and post-semester interviews, and supplementary process data (e.g., notes of weekly meetings between the new implementer and ABC team at the large public university), we describe and characterize the multi-faceted instructor experience. This includes her experience learning about the curriculum and online tools, implementing the class and adjusting her teaching practices, and assessing her studentsā engagement with the course and understanding of dynamics concepts. Our findings suggest further areas of inquiry for studies of faculty practices around curriculum adoption, including probing opportunities for cross-institutional collaborations to share materials and transform courses, interrogating variation in mechanical engineering department and student cultures, and studying sources of faculty development and support throughout the course transformation process
Analyzing an Abbreviated Dynamics Concept Inventory and Its Role as an Instrument for Assessing Emergent Learning Pedagogies
The Dynamics Concept Inventory (DCI) is a validated assessment tool commonly used to evaluate student growth within core, gateway-level mechanics courses. This research explored the evaluative use of this tool within the context of Freeform ā an emergent course system that buttresses active class meetings with blended and collaborative virtual learning environments, themselves founded upon extensive multimedia content and interactive forums ā at Purdue University. The paper specifically considers a number of related issues including: (i) the thoughtful development (via expert content validation) and statistical reliability of an abbreviated DCI instrument, which is more amenable to in-class implementation than the much longer full DCI; (ii) the correlation of abbreviated-DCI performance with exam scores and final course grades for a dynamics course using the Freeform framework with an emphasis on both conceptual understanding and traditional problem-solving skills; and (iii) various inter-section performance metrics in a preliminary study on how an implementation of the abbreviated-DCI may help elucidate the impact of the instructor within the Freeform framework. The results of these analyses supported the validity and reliability of the abbreviated DCI tool, and demonstrated its usefulness in a formal research setting. The preliminary study suggested that the Freeform framework might normalize differences in instructor pedagogical choices and student performance across class sections. These findings indicate that the abbreviated DCI holds promise as a research instrument and lay the groundwork for future inquiry into the impact of the Freeform instructional framework on students and instructors alike
Hierarchical metabolomics demonstrates substantial compositional similarity between genetically-modified and conventional potato crops
There is current debate whether genetically modified (GM) plants might contain unexpected, potentially undesirable changes in overall metabolite composition. However, appropriate analytical technology and acceptable metrics of compositional similarity require development. We describe a comprehensive comparison of total metabolites in field-grown GM and conventional potato tubers using a hierarchical approach initiating with rapid metabolome āfingerprintingā to guide more detailed profiling of metabolites where significant differences are suspected. Central to this strategy are data analysis procedures able to generate validated, reproducible metrics of comparison from complex metabolome data. We show that, apart from targeted changes, these GM potatoes in this study appear substantially equivalent to traditional cultivars
cDNA Library Generation for the Analysis of Small RNAs by High-Throughput Sequencing
The RNome of a cell is highly diverse and consists besides messenger RNAs (mRNAs), transfer RNAs (tRNAs), and ribosomal RNAs (rRNAs) also of other small and long transcript entities without apparent coding potential. This class of molecules, commonly referred to as non-protein-coding RNAs (ncRNAs), is involved in regulating numerous biological processes and thought to contribute to cellular complexity. Therefore, much effort is put into their identification and further functional characterization. Here we provide a cost-effective and reliable method for cDNA library construction of small RNAs in the size range of 20-500 residues. The effectiveness of the described method is demonstrated by the analysis of ribosome-associated small RNAs in the eukaryotic model organism Trypanosoma brucei
Ethics-in-practice in fragile contexts: research in education for displaced persons, refugees and asylum seekers
The rising numbers of forcibly displaced peoples on the move globally, and the challenges with providing access to education, reflects the shifting and complex times that we live in. Even though there has been a proliferation in educational research in the context of forced migration, in line with the increasing number of forced migrants, there has not been a commensurate focus on unpicking the increasingly complex ethical conditions within which researchers and participants operate. To examine this issue, the article provides three narrated accounts by researchers in this field and explores the interaction of researcher and researcher-author voice to critically appraise their research experience and identify critical reflections of understanding of ethics-in-practice in fragile contexts. These narratives are framed by the CERD ethical appraisal framework which explores ethical thinking through four ethical lenses ā Consequential, Ecological, Relational and Deontological. The article contributes to a deeper understanding of ethics-in-practice as a central dimension in educational research. The implications of this work show how one-size-fits-all approach to ethical appraisal is inappropriate for a socially just educational research. This work also illustrates the importance of attending to relationships and voice of the forcibly displaced, both of which are often lacking in educational research in fragile contexts
2D characterization of near-surface V P/V S: surface-wave dispersion inversion versus refraction tomography
International audienceThe joint study of pressure (P-) and shear (S-) wave velocities (Vp and Vs ), as well as their ratio (Vp /Vs), has been used for many years at large scales but remains marginal in near-surface applications. For these applications, and are generally retrieved with seismic refraction tomography combining P and SH (shear-horizontal) waves, thus requiring two separate acquisitions. Surface-wave prospecting methods are proposed here as an alternative to SH-wave tomography in order to retrieve pseudo-2D Vs sections from typical P-wave shot gathers and assess the applicability of combined P-wave refraction tomography and surface-wave dispersion analysis to estimate Vp/Vs ratio. We carried out a simultaneous P- and surface-wave survey on a well-characterized granite-micaschists contact at Ploemeur hydrological observatory (France), supplemented with an SH-wave acquisition along the same line in order to compare Vs results obtained from SH-wave refraction tomography and surface-wave profiling. Travel-time tomography was performed with P- and SH- wave first arrivals observed along the line to retrieve Vtomo p and Vtomo s models. Windowing and stacking techniques were then used to extract evenly spaced dispersion data from P-wave shot gathers along the line. Successive 1D Monte Carlo inversions of these dispersion data were performed using fixed Vp values extracted from Vtomo p the model and no lateral constraints between two adjacent 1D inversions. The resulting 1D Vsw s models were then assembled to create a pseudo-2D Vsw s section, which appears to be correctly matching the general features observed on the section. If the pseudo-section is characterized by strong velocity incertainties in the deepest layers, it provides a more detailed description of the lateral variations in the shallow layers. Theoretical dispersion curves were also computed along the line with both and models. While the dispersion curves computed from models provide results consistent with the coherent maxima observed on dispersion images, dispersion curves computed from models are generally not fitting the observed propagation modes at low frequency. Surface-wave analysis could therefore improve models both in terms of reliability and ability to describe lateral variations. Finally, we were able to compute / sections from both and models. The two sections present similar features, but the section obtained from shows a higher lateral resolution and is consistent with the features observed on electrical resistivity tomography, thus validating our approach for retrieving Vp/Vs ratio from combined P-wave tomography and surface-wave profiling
Fructan and its relationship to abiotic stress tolerance in plants
Numerous studies have been published that attempted to correlate fructan concentrations with freezing and drought tolerance. Studies investigating the effect of fructan on liposomes indicated that a direct interaction between membranes and fructan was possible. This new area of research began to move fructan and its association with stress beyond mere correlation by confirming that fructan has the capacity to stabilize membranes during drying by inserting at least part of the polysaccharide into the lipid headgroup region of the membrane. This helps prevent leakage when water is removed from the system either during freezing or drought. When plants were transformed with the ability to synthesize fructan, a concomitant increase in drought and/or freezing tolerance was confirmed. These experiments indicate that besides an indirect effect of supplying tissues with hexose sugars, fructan has a direct protective effect that can be demonstrated by both model systems and genetic transformation
The Bankruptcy Abuse Prevention and Consumer Protection Act: Means-Testing or Mean Spirited?
Thousands of U.S. households filed for bankruptcy just before the bankruptcy law changed in 2005. That rush-to-file was more pronounced, we find, in states with more generous bankruptcy exemptions and lower credit scores. We take that finding as evidence that the new law effectively reduces exemptions, which in turn should reduce the ādemandā for bankruptcy and the resulting losses to suppliers of consumer credit. We expect the savings to suppliers will be shared with borrowers by way of lower credit card rates, although credit card spreads have not yet fallen. If cheaper credit is the upside of the new law, the downside is reduced bankruptcy āinsuranceā against bad luck. The overall impact of the new law on the average household depends on how one weighs those two sides
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