698 research outputs found
Simple computer method provides contours for radiological images
Computer is provided with information concerning boundaries in total image. Gradient of each point in digitized image is calculated with aid of threshold technique; then there is invoked set of algorithms designed to reduce number of gradient elements and to retain only major ones for definition of contour
Teaching and understanding of quantum interpretations in modern physics courses
Just as expert physicists vary in their personal stances on interpretation in
quantum mechanics, instructors vary on whether and how to teach interpretations
of quantum phenomena in introductory modern physics courses. In this paper, we
document variations in instructional approaches with respect to interpretation
in two similar modern physics courses recently taught at the University of
Colorado, and examine associated impacts on student perspectives regarding
quantum physics. We find students are more likely to prefer realist
interpretations of quantum-mechanical systems when instructors are less
explicit in addressing student ontologies. We also observe contextual
variations in student beliefs about quantum systems, indicating that
instructors who choose to address questions of ontology in quantum mechanics
should do so explicitly across a range of topics.Comment: 18 pages, references, plus 2 pages supplemental materials. 8 figures.
PACS: 01.40.Fk, 03.65.-
Development of quantum perspectives in modern physics
Introductory undergraduate courses in classical physics stress a perspective
that can be characterized as realist; from this perspective, all physical
properties of a classical system can be simultaneously specified and thus
determined at all future times. Such a perspective can be problematic for
introductory quantum physics students, who must develop new perspectives in
order to properly interpret what it means to have knowledge of quantum systems.
We document this evolution in student thinking in part through pre- and
post-instruction evaluations using the Colorado Learning Attitudes about
Science Survey. We further characterize variations in student epistemic and
ontological commitments by examining responses to two essay questions, coupled
with responses to supplemental quantum attitude statements. We find that, after
instruction in modern physics, many students are still exhibiting a realist
perspective in contexts where a quantum-mechanical perspective is needed. We
further find that this effect can be significantly influenced by instruction,
where we observe variations for courses with differing learning goals. We also
note that students generally do not employ either a realist or a quantum
perspective in a consistent manner.Comment: 18 pages, plus references; 3 figures; 9 tables. PACS: 01.40.Fk,
03.65._
Development and Uses of Upper-division Conceptual Assessment
The use of validated conceptual assessments alongside more standard course
exams has become standard practice for the introductory courses in many physics
departments. These assessments provide a more standard measure of certain
learning goals, allowing for comparisons of student learning across
instructors, semesters, and institutions. Researchers at the University of
Colorado Boulder have developed several similar assessments designed to target
the more advanced physics content of upper-division classical mechanics,
electrostatics, quantum mechanics, and electrodynamics. Here, we synthesize the
existing research on our upper-division assessments and discuss some of the
barriers and challenges associated with developing, validating, and
implementing these assessments as well as some of the strategies we have used
to overcome these barriers.Comment: 12 pages, 5 figures, submitted to the Phys. Rev. ST - PER Focused
collection on Upper-division PE
Concurrent Transitional Meningioma and Ceruminous Gland Adenocarcinoma in a Scottish Wildcat Hybrid (Felis silvestris)
The Scottish wildcat (Felis silvestris) is an iconic and endangered subpopulation of the European wildcat (F.silvestris silvestris). There is much research devoted to the ecology, genetics and conservation of this animal, but little published information on pathology and disease. The investigation and reporting of such information is vital to furthering understanding of the effects of hybridization, a factor that is crucial if we are to secure a future for the Scottish wildcat. This report describes the clinical presentation, gross post-mortem and histological findings in an elderly Scottish wildcat hybrid with concurrent transitional meningioma and ceruminous gland adenocarcinoma
Tuberculosis prevalence survey in Kashmir valley
A tuberculosis prevalence survey was conducted in about 18,000 persons in
Kashmir valley situated about 1650 m above the mean sea level. All persons
were tested with 3 IU of PPD-S and 10 units of PPD-B. Persons aged 5 yr
and above were X-rayed (70 mm X-ray), and from such persons whose photofluorograms
were interpreted as abnormal two specimens of sputum were
collected and bacteriologically examined. In addition, a large X-ray of the
chest was taken for children aged 0-4 yr who had reactions of 10 mm or more
to PPD-S. They were then clinically examined by a paediatrician, taking into
account all available data, for evaluation for any evidence of tuberculosis.
The results of the survey showed that the prevalence of non-specific sensitivity
(59%) in the Kashmir valley is significant. The prevalence of tuberculous infection
was 38 per cent. The prevalence of culture positive tuberculous patients
(3 per 1000) and that of abacillary X-ray positive patients (14 per 1000) were
found to be similar in the two sexes contrary to the usual experience of a
higher prevalence among males. Results from studies of phage typing, susceptibility
to thiophen-2-carbonic acid hydrazide (TCH) and virulence in the
guineapig of strains obtained from patients diagnosed in the survey showed
that most of these strains belonged to phage type A, were resistant to TCH
and were not of low virulence. Regional variations in the prevalence rates
were seen, the- problem of tuberculosis appeared to he more in the Baramulla
district as compared to Srinagar and Anantnag districts. A comparison of results
obtained from the present survey with those obtained from the BCG trial
in Chingleput (Tamil Nadu) revealed that the tuberculosis situation in the
two areas was quite different
The Clinical Alliance and Research in Electroconvulsive Therapy Network: An Australian Initiative for Improving Service Delivery of Electroconvulsive Therapy
Objective There is currently substantial heterogeneity in electroconvulsive therapy (ECT) treatment methods between clinical settings. Understanding how this variation in clinical practice is related to treatment outcomes is essential for optimizing service delivery. The Clinical Alliance and Research in ECT Network is a clinical and research framework with the aims of improving clinical practice, enabling auditing and benchmarking, and facilitating the collection of naturalistic clinical data. Methods The network framework and clinical and treatment variables collected and rationale for the use of particular outcome measures are described. Survey results detailing the use of ECT across initial participating clinical centers were examined. Results The data are reported from 18 of 22 participating centers, the majority based in Australia. Melancholic unipolar depression was the most common clinical indication (78%). Right unilateral (44%) and bifrontal (39%) were the most commonly used electrode placements. Eighty one percent of the centers used individual seizure titration for initial dosing. Conclusions There was substantial heterogeneity in the use of ECT between participating centers, indicating that the Network is representative of modern ECT practice. The Clinical Alliance and Research in ECT Network may therefore offer the opportunity to improve service delivery and facilitate the investigation of unresolved research questions pertaining to modern ECT practice
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