3,943 research outputs found
Quantifying the Effectiveness of Interactive Tutorials in Medical Library Instruction
The goal of this study was to determine whether a passive or an interactive tutorial design improves understanding of key concepts, as measured by pre- and post-test data. The authors also collected data regarding the participantsâ preference for taking an interactive versus a passive tutorial. The interactive tutorial group improved statistically significantly from pre-test to post-test for all three learning questions. While the passive tutorial group improved from pre-test to post-test on all three questions, the improvement was statistically significant for just two of the three questions. The majority of the participants preferred interactive tutorials (78%) to passive tutorials (22%)
Incipient order in the t-J model at high temperatures
We analyze the high-temperature behavior of the susceptibilities towards a
number of possible ordered states in the t-J-V model using the high-temperature
series expansion. From all diagrams with up to ten edges, reliable results are
obtained down to temperatures of order J, or (with some optimism) to J/2. In
the unphysical regime, t<J, large superconducting susceptibilities are found,
which moreover increase with decreasing temperatures, but for t>J, these
susceptibilities are small and decreasing with decreasing temperature; this
suggests that the t-J model does not support high-temperature
superconductivity. We also find modest evidence of a tendency toward nematic
and d-density wave orders.
ERRATUM: Due to an error in the calculation, the series for d-wave
supeconducting and extended s-wave superconducting orders were incorrect. We
recalculate the series and give the replacement figures. In agreement with our
earlier findings, we still find no evidence of any strong enhancement of the
superconducting susceptibility with decreasing temperature. However, because
different Pade approximants diverge from each other at somewhat higher
temperatures than we originally found, it is less clear what this implies
concerning the presence or absence of high-temperature superconductivity in the
t-J model.Comment: 4 pages, 5 eps figures included; ERRATUM 2 pages, 3 eps figures
correcting the error in the series for superconducting susceptibilitie
An improved long-wave radiometer
May also be cited as: WHOI-00-13This report describes the development of an improved long-wave radiometer (pyrgeometer) for deployment on ships and buoys. Standard pyrgeometers use a thermopile to measure the temperature gradient between the receiver surface and the instrument case, and thus infer the receiver temperature and incident radiation. The key design change employed in the new radiometer is to remove the thermopile and replace it with a small, glass-encapsulated thermistor to measure the receiver temperature directly. To prove the concept, a prototype radiometer was built and calibrated. It was then deployed outside for a period of a week on the roof of the Clark Laboratory (Quissett Campus, Woods Hole Oceanographic Institution) to demonstrate the feasability of the new concept. Data from the prototype were compared to those from a pair of standard radiometers. The intercomparison shows that the prototype performed surprisingly well. It was able to capture all the variability observed by the standards with only a small bias. The next step in the design process, which has been funded by the National Science Foundation, is to build a rugged version of the prototype that can be deployed in the field.Funding was provided by the Cecil H. and Ida M. Green Technology Innovations Awards Program and the National Science Foundation, Grant OCE98-18470
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Disparity between General Symptom Relief and Remission Criteria in the Positive and Negative Syndrome Scale (PANSS): A Post-treatment Bifactor Item Response Theory Model.
Objective: Total scale scores derived by summing ratings from the 30-item PANSS are commonly used in clinical trial research to measure overall symptom severity, and percentage reductions in the total scores are sometimes used to document the efficacy of treatment. Acknowledging that some patients may have substantial changes in PANSS total scores but still be sufficiently symptomatic to warrant diagnosis, ratings on a subset of 8 items, referred to here as the "Remission set," are sometimes used to determine if patients' symptoms no longer satisfy diagnostic criteria. An unanswered question remains: is the goal of treatment better conceptualized as reduction in overall symptom severity, or reduction in symptoms below the threshold for diagnosis? We evaluated the psychometric properties of PANSS total scores, to assess whether having low symptom severity post-treatment is equivalent to attaining Remission. Design: We applied a bifactor item response theory (IRT) model to post-treatment PANSS ratings of 3,647 subjects diagnosed with schizophrenia assessed at the termination of 11 clinical trials. The bifactor model specified one general dimension to reflect overall symptom severity, and five domain-specific dimensions. We assessed how PANSS item discrimination and information parameters varied across the range of overall symptom severity (θ), with a special focus on low levels of symptoms (i.e., θ<-1), which we refer to as "Relief" from symptoms. A score of θ=-1 corresponds to an expected PANSS item score of 1.83, a rating between "Absent" and "Minimal" for a PANSS symptom. Results: The application of the bifactor IRT model revealed: (1) 88% of total score variation was attributable to variation in general symptom severity, and only 8% reflected secondary domain factors. This implies that a general factor may provide a good indicator of symptom severity, and that interpretation is not overly complicated by multidimensionality; (2) Post-treatment, 534 individuals (about 15% of the whole sample) scored in the "Relief" range of general symptom severity, but more than twice that number (n = 1351) satisfied Remission criteria (37%). 2 in 3 Remitted patients had scores that were not in a low symptom range (corresponding to Absent or Minimal item scores); (3) PANSS items vary greatly in their ability to measure the general symptom severity dimension; while many items are highly discriminating and relatively "pure" indicators of general symptom severity (delusions, conceptual disorganization), others are better indicators of specific dimensions (blunted affect, depression). The utility of a given PANSS item for assessing a patient depended on the illness level of the patient. Conclusion: Satisfying conventional Remission criteria was not strongly associated with low levels of symptoms. The items providing the most information for patients in the symptom Relief range were Delusions, Preoccupation, Suspiciousness Persecution, Unusual Thought Content, Conceptual Disorganization, Stereotyped Thinking, Active Social Avoidance, and Lack of Judgment and Insight. Lower scores on these items (item scores â¤2) were strongly associated with having a low latent trait θ or experiencing overall symptom relief. The inter-rater agreement between Remission and Relief subjects suggested that these criteria identified different subsets of patients. Alternative subsets of items may offer better indicators of general symptom severity and provide better discrimination (and lower standard errors) for scaling individuals and judging symptom relief, where the "best" subset of items ultimately depends on the illness range and treatment phase being evaluated
Analysis of H.R. 2646 on Land Tenure Arrangements on U.S. Representative and Texas FARM Assistance Farms
This report analyzes whether H.R. 2646 may provide economic incentives for landlords to end current land tenure arrangements with tenants and take over management (and government payments) associated with their land. This work is a followup to Briefing Paper 01-9, Representative Farm Analysis of the H.R. 2646 Farm Bill Proposal that analyzes the impacts of H.R. 2646 on the representative crop farms maintained by the Agricultural and Food Policy Center (AFPC).Agribusiness, Agricultural and Food Policy, Land Economics/Use,
Representative Farm Analysis of the S. 1731 Farm Bill Proposal
Agribusiness, Agricultural and Food Policy,
Analysis of the Effects of Proposed House and Senate Farm Bills on Rice Returns
This report reflects analysis of projected gross returns under the proposed farm programs â H.R. 2646 the House Bill that passed the House floor on October 5th, the Senate Bill that passed the Senate Agriculture Committee on November 15th and the Cochran/Roberts Bill that was defeated previously in committee.Agricultural and Food Policy,
A Unitary Measure of L2 Silent Reading Fluency Accounting for Comprehension
This research presents a novel reading fluency (rf) measurement formula that accounts for both reading rate and comprehension. Possible formulas were investigated with 68 participants in a strategic reading course in an IEP at a small Pacific Island university. The selected formulaâs scores demonstrated concurrent validity through strong correlation (r[66] = .680, p < .001) with the Adaptive Reading Test (ART), an assessment aligned with ACTFLâs proficiency levels. Furthermore, when ART scores were regressed onto formula scores, formula scores accounted for 49% of the variance in ART scores (R2 = .488, F[1, 66] = 62.88, p < .001); these results were comparable to a model in which comprehension and rate were the independent variables (R2 = .514, F[2, 65] = 34.38, p < .001). The formula appears preferable to currently available alternatives and ensures that high performance in reading rate cannot compensate for low performance in comprehension nor vice versa. An Excel workbook for exploring formula variants and tracking learnersâ fluency is provided to readers of Reading in a Foreign Language
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