620 research outputs found
The use of secondary school student ratings of their teacher’s skillfulness for low-stake assessment and high-stake evaluation
Previous studies in higher education have shown that the reliability of student ratings of teaching skill increases if multiple ratings by different students are aggregated. This study examines the generalizability of these findings to the context of secondary education. Also, it seeks to validate these findings by comparing reliability levels estimated by the routinely used nested design with those estimated using a more complex design. The sample consisted of 410 students from 17 classes rating 63 teachers working at eight schools across the Netherlands. Using the nested design, the study replicates findings of previous studies in higher education. The findings illustrate how the reliability level of secondary school students’ ratings increases with an increasing number of students. However, these replicated reliability levels were not validated by the more complex design which provided lower estimates. This indicates that the nested design may not provide accurate estimations of rating reliability
Next-to-leading-order predictions for t-channel single-top production at hadron colliders
We present the predictions at next-to-leading order (NLO) in the strong
coupling for the single-top cross section in the t channel at the Tevatron and
the LHC. Our calculation starts from the 2 -> 3 Born amplitude g q -> t bbar
q', keeping the b-quark mass non-zero. A comparison is performed with a
traditional NLO calculation of this channel based on the 2 -> 2 Born process
with a bottom quark in the initial state. In particular, the effect of using
kinematic approximations and resumming logarithms of the form log(Q^2/m_b^2) in
the 2 -> 2 process is assessed. Our results show that the 2 -> 3 calculation is
very well behaved and in substantial agreement with the predictions based on
the 2 -> 2 process.Comment: 5 pages, 5 figures. Updated results with more recent CTEQ6.6 PDF set.
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Screening for mild cognitive impairment in the preoperative setting: A narrative review
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251958.pdf (Publisher’s version ) (Open Access)Cognitive impairment predisposes patients to the development of delirium and postoperative cognitive dysfunction. In particular, in older patients, the adverse sequelae of cognitive decline in the perioperative period may contribute to adverse outcomes after surgical procedures. Subtle signs of cognitive impairment are often not previously diagnosed. Therefore, the aim of this review is to describe the available cognitive screeners suitable for preoperative screening and their psychometric properties for identifying mild cognitive impairment, as preoperative workup may improve perioperative care for patients at risk for postoperative cognitive dysfunction. Electronic systematic and snowball searches of PubMed, PsycInfo, ClinicalKey, and ScienceDirect were conducted for the period 2015–2020. Major inclusion criteria for articles included those that discussed a screener that included the cognitive domain ‘memory’, that had a duration time of less than 15 min, and that reported sensitivity and specificity to detect mild cognitive impairment. Studies about informant-based screeners were excluded. We provided an overview of the characteristics of the cognitive screener, such as interrater and test-retest reliability correlations, sensitivity and specificity for mild cognitive impairment and cognitive impairment, and duration of the screener and cutoff points. Of the 4775 identified titles, 3222 were excluded from further analysis because they were published prior to 2015. One thousand four hundred and forty-eight titles did not fulfill the inclusion criteria. All abstracts of 52 studies on 45 screeners were examined of which 10 met the inclusion criteria. For these 10 screeners, a further snowball search was performed to obtain related studies, resulting in 20 articles. Screeners included in this review were the Mini-Cog, MoCA, O3DY, AD8, SAGE, SLUMS, TICS(-M), QMCI, MMSE2, and Mini-ACE. The sensitivity and specificity range to detect MCI in an older population is the highest for the MoCA, with a sensitivity range of 81–93% and a specificity range of 74–89%. The MoCA, with the highest combination of sensitivity and specificity, is a feasible and valid routine screening of pre-surgical cognitive function. This warrants further implementation and validation studies in surgical pathways with a large proportion of older patients.21 p
PHYSICAL ACTIVITY AND COGNITIVE FUNCTION OF LONG DISTANCE WALKERS: STUDYING FOUR DAYS MARCHES PARTICIPANTS.
OBJECTIVE: Studies show physical activity to be beneficial for cognitive function. However, studies usually included individuals who were not particularly inclined to exercise. Following research among master athletes, we examined associations between physical activity and cognitive function in participants of the International Nijmegen Four Days Marches. These individuals are also inclined to exercise. On 4 consecutive days > 40,000 participants walk a daily distance of 30-50 km (120-200 km or 75-125 miles in total). METHOD: Four Days Marches participants and less active or inactive control participants from the Nijmegen Exercise Study were examined. Self-reported current and lifelong physical activities were quantified in Metabolic Equivalent of Task minutes/day and training walking speed was estimated in km/h. Cognitive functioning in the domains of working memory, executive function, and visuospatial short-term memory was assessed using the validated Brain Aging Monitor. RESULTS: Data from 521 participants (mean age 54.7, standard deviation 12.9) showed neither positive associations between lifelong physical activity and working memory, executive function, and visuospatial short-term memory nor positive associations between current physical activity and cognitive functioning in these domains (P-values > 0.05). However, a positive association between training walking speed and working memory was revealed (age adjusted Beta = 0.18, P-value < 0.01). CONCLUSION: Walking speed, as a surrogate marker of fitness, but not lifelong and current physical activity levels were associated with cognitive function. Therefore, walking speed deserves more attention in research aimed at unravelling associations between physical activity and cognitive function
On the "association between two things":the case of student surveys and classroom observations of teaching quality
This study examines the association between two measures of teaching effectiveness—a student survey measure and a classroom observation measure—to determine whether their correlation depends on the study design. The sample includes 160 classroom observations of 56 teachers across 15 classes, in which students also rated the teachers with a survey. Dependencies are examined using generalizability theory. Results suggest that the correlation between the survey and observation measures depends on the number of classroom observations, the number of student ratings, and whether the designs are nested or partially nested. The effect is substantial: Predicted correlations range between 0.10–0.80 for the same variables with different study designs. In particular, the number of classroom observations has a notable influence, such that across all investigated scenarios, the correlation doubles when observers visit three lessons instead of one. Correlations also tend to be positively biased when research designs are nested
Early postural blood pressure response and cause-specific mortality among middle-aged adults: what is the role of diastolic blood pressure?
NLO predictions for t-channel production of single top and fourth generation quarks at hadron colliders
We present updated NLO predictions for the electroweak t-channel production
of heavy quarks at the Tevatron and at the LHC. We consider production of
single top and fourth generation t' starting from both 2 to 2 and 2 to 3 Born
processes. Predictions for tb' and t'b' cross sections at NLO are also given
for the first time. A thorough study of the theoretical uncertainties coming
from parton distribution functions, renormalisation and factorisation scale
dependence and heavy quark masses is performed.Comment: 25 pages, 8 figure
A Simple and Practical Index to Measure Dementia-Related Quality of Life
AbstractBackgroundResearch on new treatments for dementia is gaining pace worldwide in an effort to alleviate this growing health care problem. The optimal evaluation of such interventions, however, calls for a practical and credible patient-reported outcome measure.ObjectivesTo describe the refinement of the Dementia Quality-of-life Instrument (DQI) and present its revised version.MethodsA prototype of the DQI was adapted to cover a broader range of health-related quality of life (HRQOL) and to improve consistency in the descriptions of its domains. A valuation study was then conducted to assign meaningful numbers to all DQI health states. Pairs of DQI states were presented to a sample of professionals working with people with dementia and a representative sample of the Dutch population. They had to repeatedly select the best DQI state, and their responses were statistically modeled to obtain values for each health state.ResultsIn total, 207 professionals working with people with dementia and 631 members of the general population completed the paired comparison tasks. Statistically significant differences between the two samples were found for the domains of social functioning, mood, and memory. Severe problems with physical health and severe memory problems were deemed most important by the general population. In contrast, severe mood problems were considered most important by professionals working with people with dementia.DiscussionThe DQI is a simple and feasible measurement instrument that expresses the overall HRQOL of people suffering from dementia in a single meaningful number. Current results suggest that revisiting the discussion of using values from the general population might be warranted in the dementia context
The effect of an interactive cycling training on cognitive functioning in older adults with mild dementia: study protocol for a randomized controlled trial
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168861.pdf (publisher's version ) (Open Access)Background: To date there is no cure or an effective disease-modifying drug to treat dementia. Available acetylcholine-esterase inhibiting drugs or memantine only produce small benefits on cognitive and behavioural functioning and their clinical relevance remains controversial. Combined cognitive-aerobic interventions are an appealing alternative or add-on to current pharmacological treatments. The primary aim of this study is to investigate the efficacy of a combined cognitive-aerobic training and a single aerobic training compared to an active control group in older adults with mild dementia. We expect to find a beneficial effect on executive functioning in both training regimes, compared to the control intervention, with the largest effect in the combined cognitive-aerobic group. Secondary, intervention effects on cognitive functioning in other domains, physical functioning, physical activity levels, activities of daily living, frailty and quality of life are studied. Methods: The design is a single-blind, randomized controlled trial (RCT) with three groups: a combined cognitive-aerobic bicycle training (interactive cycling), a single aerobic bicycle training and a control intervention, which consists of stretching and toning exercises. Older adults with mild dementia follow a 12-week training program consisting of three training sessions of 30-40 min per week. The primary study outcome is objective executive functioning measured with a neuropsychological assessment. Secondary measures are objective cognitive functioning in other domains, physical functioning, physical activity levels, activities of daily living, frailty, mood and quality of life. The three groups are compared at baseline, after 6 and 12 weeks of training, and at 24-week follow-up. Discussion: This study will provide novel information on the effects of an interactive cycling training on executive function in older adults with mild dementia. Furthermore, since this study has both a combined cognitive-aerobic training and a single aerobic training group the effectiveness of the different components of the intervention can be identified. The results of this study may be used for physical and mental activity recommendations in older adults with dementia.8 p
Precondition Inference via Partitioning of Initial States
Precondition inference is a non-trivial task with several applications in
program analysis and verification. We present a novel iterative method for
automatically deriving sufficient preconditions for safety and unsafety of
programs which introduces a new dimension of modularity. Each iteration
maintains over-approximations of the set of \emph{safe} and \emph{unsafe}
\emph{initial} states. Then we repeatedly use the current abstractions to
partition the program's \emph{initial} states into those known to be safe,
known to be unsafe and unknown, and construct a revised program focusing on
those initial states that are not yet known to be safe or unsafe. An
experimental evaluation of the method on a set of software verification
benchmarks shows that it can solve problems which are not solvable using
previous methods.Comment: 19 pages, 8 figure
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