2,206 research outputs found
Topological Aspects of Epistemology and Metaphysics
The aim of this paper is to show that (elementary) topology may be useful for dealing with problems of epistemology and metaphysics. More precisely, I want to show that the introduction of topological structures may elucidate the role of the spatial structures (in a broad sense) that underly logic and cognition. In some detail Iâll deal with âCassirerâs problemâ that may be characterized as an early forrunner of Goodmanâs âgrue-bleenâ problem. On a larger scale, topology turns out to be useful in elaborating the approach of conceptual spaces that in the last twenty years or so has found quite a few applications in cognitive science, psychology, and linguistics. In particular, topology may help distinguish ânaturalâ from ânot-so-naturalâ concepts. This classical problem that up to now has withstood all efforts to solve (or dissolve) it by purely logical methods. Finally, in order to show that a topological perspective may also offer a fresh look on classical metaphysical problems, it is shown that Leibnizâs famous principle of the identity of indiscernibles is closely related to some well-known topological separation axioms. More precisely, the topological perspective gives rise in a natural way to some novel variations of Leibnizâs principle
Validation of learning style measures: implications for medical education practice
It is unclear which learners would most benefit from the more individualised, student-structured, interactive approaches characteristic of problem-based and computer-assisted learning. The validity of learning style measures is uncertain, and there is no unifying learning style construct identified to predict such learners. Objectiveâ This study was conducted to validate learning style constructs and to identify the learners most likely to benefit from problem-based and computer-assisted curricula. Methodsâ Using a cross-sectional design, 3 established learning style inventories were administered to 97 post-Year 2 medical students. Cognitive personality was measured by the Group Embedded Figures Test, information processing by the Learning Styles Inventory, and instructional preference by the Learning Preference Inventory. The 11 subscales from the 3 inventories were factor-analysed to identify common learning constructs and to verify construct validity. Concurrent validity was determined by intercorrelations of the 11 subscales. Resultsâ A total of 94 pre-clinical medical students completed all 3 inventories. Five meaningful learning style constructs were derived from the 11 subscales: student- versus teacher-structured learning; concrete versus abstract learning; passive versus active learning; individual versus group learning, and field-dependence versus field-independence. The concurrent validity of 10 of 11 subscales was supported by correlation analysis. Medical students most likely to thrive in a problem-based or computer-assisted learning environment would be expected to score highly on abstract, active and individual learning constructs and would be more field-independent. Conclusionsâ Learning style measures were validated in a medical student population and learning constructs were established for identifying learners who would most likely benefit from a problem-based or computer-assisted curriculum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72443/1/j.1365-2929.2006.02476.x.pd
A pedagogic appraisal of the Priority Heuristic
We have explored how science and mathematics teachers made decisions when confronted with a dilemma in which a fictitious young woman, Deborah, may choose to have an operation that might address a painful spinal condition. We sought to explore the extent to which psychological heuristic models, in particular the Priority Heuristic, might successfully describe the decision-making process of these teachers and how an analysis of the role of personal and emotional factors in shaping the decision-making process might inform pedagogical design. A novel aspect of this study is that the setting in which the decision-making process is examined contrasts sharply with those used in psychological experiments. We found that to some extent, even in this contrasting setting, the Priority Heuristic could describe these teachers' decision-making. Further analysis of the transcripts yielded some insights into limitations on scope as well the richness and complexity in how personal factors were brought to bear. We see these limitations as design opportunities for educational intervention
Pathologies in Asymptotically Lifshitz Spacetimes
There has been significant interest in the last several years in studying
possible gravitational duals, known as Lifshitz spacetimes, to anisotropically
scaling field theories by adding matter to distort the asymptotics of an AdS
spacetime. We point out that putative ground state for the most heavily studied
example of such a spacetime, that with a flat spatial section, suffers from a
naked singularity and further point out this singularity is not resolvable by
any known stringy effect. We review the reasons one might worry that
asymptotically Lifshitz spacetimes are unstable and employ the initial data
problem to study the stability of such systems. Rather surprisingly this
question, and even the initial value problem itself, for these spacetimes turns
out to generically not be well-posed. A generic normalizable state will evolve
in such a way to violate Lifshitz asymptotics in finite time. Conversely,
enforcing the desired asymptotics at all times puts strong restrictions not
just on the metric and fields in the asymptotic region but in the deep interior
as well. Generically, even perturbations of the matter field of compact support
are not compatible with the desired asymptotics.Comment: 36 pages, 1 figure, v2: Enhanced discussion of singularity, including
relationship to Gubser's conjecture and singularity in RG flow solution, plus
minor clarification
Coarse-grained reconfigurable array architectures
Coarse-Grained ReconïŹgurable Array (CGRA) architectures accelerate the same inner loops that beneïŹt from the high ILP support in VLIW architectures. By executing non-loop code on other cores, however, CGRAs can focus on such loops to execute them more efïŹciently. This chapter discusses the basic principles of CGRAs, and the wide range of design options available to a CGRA designer, covering a large number of existing CGRA designs. The impact of different options on ïŹexibility, performance, and power-efïŹciency is discussed, as well as the need for compiler support. The ADRES CGRA design template is studied in more detail as a use case to illustrate the need for design space exploration, for compiler support and for the manual ïŹne-tuning of source code
Random walk with barriers: Diffusion restricted by permeable membranes
Restrictions to molecular motion by barriers (membranes) are ubiquitous in
biological tissues, porous media and composite materials. A major challenge is
to characterize the microstructure of a material or an organism
nondestructively using a bulk transport measurement. Here we demonstrate how
the long-range structural correlations introduced by permeable membranes give
rise to distinct features of transport. We consider Brownian motion restricted
by randomly placed and oriented permeable membranes and focus on the
disorder-averaged diffusion propagator using a scattering approach. The
renormalization group solution reveals a scaling behavior of the diffusion
coefficient for large times, with a characteristically slow inverse square root
time dependence. The predicted time dependence of the diffusion coefficient
agrees well with Monte Carlo simulations in two dimensions. Our results can be
used to identify permeable membranes as restrictions to transport in disordered
materials and in biological tissues, and to quantify their permeability and
surface area.Comment: 8 pages, 3 figures; origin of dispersion clarified, refs adde
Multilevel Deconstruction of the In Vivo Behavior of Looped DNA-Protein Complexes
Protein-DNA complexes with loops play a fundamental role in a wide variety of
cellular processes, ranging from the regulation of DNA transcription to
telomere maintenance. As ubiquitous as they are, their precise in vivo
properties and their integration into the cellular function still remain
largely unexplored. Here, we present a multilevel approach that efficiently
connects in both directions molecular properties with cell physiology and use
it to characterize the molecular properties of the looped DNA-lac repressor
complex while functioning in vivo. The properties we uncover include the
presence of two representative conformations of the complex, the stabilization
of one conformation by DNA architectural proteins, and precise values of the
underlying twisting elastic constants and bending free energies. Incorporation
of all this molecular information into gene-regulation models reveals an
unprecedented versatility of looped DNA-protein complexes at shaping the
properties of gene expression.Comment: Open Access article available at
http://www.plosone.org/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1371%2Fjournal.pone.000035
Pathology Informatics Essentials for Residents: A Flexible Informatics Curriculum Linked to Accreditation Council for Graduate Medical Education Milestones (a secondary publication)*
Context: Recognition of the importance of informatics to the practice of pathology has surged. Training residents in pathology
informatics has been a daunting task for most residency programs in the United States because faculty often lacks experience and
training resources. Nevertheless, developing resident competence in informatics is essential for the future of pathology as a
specialty.
Objective: To develop and deliver a pathology informatics curriculum and instructional framework that guides pathology
residency programs in training residents in critical pathology informatics knowledge and skills, and meets Accreditation Council
for Graduate Medical Education Informatics Milestones.
Design: The College of American Pathologists, Association of Pathology Chairs, and Association for Pathology Informatics
formed a partnership and expert work group to identify critical pathology informatics training outcomes and to create a highly
adaptable curriculum and instructional approach, supported by a multiyear change management strategy.
Results: Pathology Informatics Essentials for Residents (PIER) is a rigorous approach for educating all pathology residents in
important pathology informatics knowledge and skills. PIER includes an instructional resource guide and toolkit for incorporating informatics training into residency programs that vary in needs, size, settings, and resources. PIER is available at http://
www.apcprods.org/PIER (accessed April 6, 2016).
Conclusions: PIER is an important contribution to informatics training in pathology residency programs. PIER introduces
pathology trainees to broadly useful informatics concepts and tools that are relevant to practice. PIER provides residency program
directors with a means to implement a standardized informatics training curriculum, to adapt the approach to local program
needs, and to evaluate resident performance and progress over time
Fecal occult blood and fecal calprotectin as point-of-care markers of intestinal morbidity in Ugandan children with Schistosoma mansoni infection.
BACKGROUND: Calprotectin is a calcium-binding cytoplasmic protein found in neutrophils and increasingly used as a marker of bowel inflammation. Fecal occult blood (FOB) is also a dependable indicator of bowel morbidity. The objective of our study was to determine the applicability of these tests as surrogate markers of Schistosoma mansoni intestinal morbidity before and after treatment with praziquantel (PZQ).
METHODS: 216 children (ages 3-9 years old) from Buliisa District in Lake Albert, Uganda were examined and treated with PZQ at baseline in October 2012 with 211 of them re-examined 24 days later for S. mansoni and other soil transmitted helminths (STH). POC calprotectin and FOB assays were performed at both time points on a subset of children. Associations between the test results and infection were analysed by logistic regression.
RESULTS: Fecal calprotectin concentrations of 150-300 ”g/g were associated with S. mansoni egg patent infection both at baseline and follow up (OR: 12.5 P = 0.05; OR: 6.8 P = 0.02). FOB had a very strong association with baseline anemia (OR: 9.2 P = 0.03) and medium and high egg intensity schistosomiasis at follow up (OR: 6.6 P = 0.03; OR: 51.3 P = 0.003). Both tests were strongly associated with heavy intensity S. mansoni infections. There was a significant decrease in FOB and calprotectin test positivity after PZQ treatment in those children who had egg patent schistosomiasis at baseline.
CONCLUSIONS: Both FOB and calprotectin rapid assays were found to correlate positively and strongly with egg patent S. mansoni infection with a positive ameloriation response after PZQ treatment indicative of short term reversion of morbidity. Both tests were appropriate for use in the field with excellent operational performance and reliability. Due to its lower-cost which makes its scale-up of use affordable, FOB could be immediately adopted as a monitoring tool for PC campaigns for efficacy evaluation before and after treatment
Intravascular Ultrasound (IVUS): A Potential Arthroscopic Tool for Quantitative Assessment of Articular Cartilage
Conventional ultrasound examination of the articular cartilage performed externally on the body surface around the joint has limited accuracy due to the inadequacy in frequency used. In contrast to this, minimally invasive arthroscopy-based ultrasound with adequately high frequency may be a better alternative to assess the cartilage. Up to date, no special ultrasound transducer for imaging the cartilage in arthroscopic use has been designed. In this study, we introduced the intravascular ultrasound (IVUS) for this purpose. An IVUS system with a catheter-based probe (Ă â 1mm) was used to measure the thickness and surface acoustical reflection of the bovine patellar articular cartilage in vitro before and after degeneration induced by enzyme treatments. Similar measurement was performed using another high frequency ultrasound system (Vevo) with a probe of much larger size and the results were compared between the two systems. The thickness measured using IVUS was highly correlated (r = 0.985, p < 0.001) with that obtained by Vevo. Thickness and surface reflection amplitude measured using IVUS on the enzymatically digested articular cartilage showed changes similar to those obtained by Vevo, which were expectedly consistent with previous investigations. IVUS can be potentially used for the quantitative assessment of articular cartilage, with its ready-to-use arthroscopic feature
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