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991.
Rebekka Darner Gougis Janet F. Stomberg Alicia T. O’Hare Catherine M. O’Reilly Nicholas E. Bader Thomas Meixner Cayelan C. Carey 《International Journal of Science and Mathematics Education》2017,15(6):1039-1056
The concepts of randomness and variation are pervasive in science. The purpose of this study was to document how post-secondary life science students explain randomness and variation, infer relationships between their explanations, and ability to describe and identify appropriate and inappropriate variation, and determine if students can identify sources of variation. An instrument designed to test statistical concepts was administered to 282 college students from three universities, ranging from introductory non-science majors to science graduate students. Students readily distinguished between causes of variation. A naïve no-pattern concept of randomness persisted from first-year non-science majors to senior-level science majors, contributing to incorrect responses on the variation instrument. Students’ expressions of randomness were better predictors of performance on the variation instrument than their expressions of variation. It is argued that inclusion of everyday language uses of randomness in instruction can bridge the gap between vernacular and scientific uses of this term. 相似文献
992.
Solution to impedance distribution in electrical impedance tomography (EIT) is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. Tikhonov regularization with some prior information is a sound regnlarization method for static electrical impedance tomography under the condition that some true impedance distribution information is known a priori. This paper presents a direct search method (DSM) as pretreatment of image reconstruction through which one not only can construct a regularization matrix which may locate in areas of impedance change, but also can obtain an initial impedance distribution more similar to the true impedance distribution, as well as better current modes which can better distinguish the initial distribution and the true distribution. Simulation results indicate that, by using DSM, resolution in the center area of the measured object can be improved significantly. 相似文献
993.
994.
Anthony Bigot Claude Chrisment Taoufiq Dkaki Gilles Hubert Josiane Mothe 《Information Retrieval》2011,14(6):617-648
To evaluate Information Retrieval Systems on their effectiveness, evaluation programs such as TREC offer a rigorous methodology
as well as benchmark collections. Whatever the evaluation collection used, effectiveness is generally considered globally,
averaging the results over a set of information needs. As a result, the variability of system performance is hidden as the
similarities and differences from one system to another are averaged. Moreover, the topics on which a given system succeeds
or fails are left unknown. In this paper we propose an approach based on data analysis methods (correspondence analysis and
clustering) to discover correlations between systems and to find trends in topic/system correlations. We show that it is possible
to cluster topics and systems according to system performance on these topics, some system clusters being better on some topics.
Finally, we propose a new method to consider complementary systems as based on their performances which can be applied for
example in the case of repeated queries. We consider the system profile based on the similarity of the set of TREC topics
on which systems achieve similar levels of performance. We show that this method is effective when using the TREC ad hoc collection. 相似文献
995.
Gupta S Verma M Gupta AK Kaur A Kaur V Singh K 《Indian journal of clinical biochemistry : IJCB》2011,26(2):178-181
Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines
recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism
and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and
the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples
(87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently
as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests.
77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7%
in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction
and order the appropriate test in a rational and cost effective manner. 相似文献
996.
Yuan Gao Ling Xia Ying-lan Gong Ding-chang Zheng 《Journal of Zhejiang University. Science. B》2018,19(1):49-56
Left anterior fascicular block (LAFB) is a heart disease identifiable from an abnormal electrocardiogram (ECG). It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intraventricular conduction delay due to the lesions of the conduction bundles and slow cell to cell conduction has also been considered as another cause of heart failure. Since the location and mechanism of conduction delay have notable variability between individual patients, we hypothesized that the impaired conduction in the ventricular myocardium may lead to abnormal ECGs similar to LAFB ECG patterns. To test this hypothesis, based on a computer model with a three dimensional whole-heart anatomical structure, we simulated the cardiac exciting sequence map and 12-lead ECG caused by the block in the left anterior fascicle and by the slowed conduction velocity in the ventricular myocardium. The simulation results showed that the typical LAFB ECG patterns can also be observed from cases with slowed conduction velocity in the ventricular myocardium. The main differences were the duration of QRS and wave amplitude. In conclusion, our simulations provide a promising starting point to further investigate the underlying mechanism of heart failure with LAFB, which would provide a potential reference for LAFB diagnosis. the angulation of impaction having little effect on facture risk. 相似文献
997.
Catherine Forde Deirdre Horgan Shirley Martin Aisling Parkes 《Journal of Educational Change》2018,19(4):489-509
In Ireland there is progressive legislation on children’s participation in the education system. The Education Act 1998 advocates that school boards should involve students in the school and establish student councils in second-level schools. Since the publication of this legislation progress on realising students’ participation in schools has been slow. In 2006 the UN Committee on the Rights of the Child recommended that Ireland strengthen its efforts to enable children to express their views in schools and other educational institutions. The National Strategy on Children and Young People’s Participation in Decision-making (2015), the first to be produced internationally, commits to facilitating children and young people’s voice in the development of education policy, the running of schools and in other areas of school policy. This paper presents and discusses the results of qualitative participatory research with children and young people aged between 7 and 17 years, teachers and school principals, and parents, on their attitudes towards and opportunities for participation by students in schools in Ireland. The data reveal that students are keen to participate in school but recognise that their opportunities to do so are inadequate, that teachers understand participation very differently from students, and that parents have little knowledge of their children’s participatory experiences in school. It concludes that effective participation in schools requires policy, practical and cultural change. 相似文献
998.
999.
1000.
Beatrice S. Bartlett 《Archival Science》2007,7(4):369-390
This article describes the first half century of the Communist government’s supervision and management of the central-government
archives of the last two dynasties. Immediately with the Communist ascent to power in 1949, the new government took great
interest in assembling and protecting the country’s archival documents, readying the Ming-Qing archives for access to scholars,
and preparing for publication of selected materials. By the 1980s Beijing’s Number One Historical Archives, in charge of the
largest holding of Ming-Qing documents, had become the first Chinese authority to complete a full sorting and preliminary
catalogues for such a collection. Moreover, to facilitate searches, an attempt has recently begun to create a subject-heading
system for these and other holdings in the country. In the first half century’s final decades, foreign researchers were admitted
for the first time and tours and international exchanges began to take place.
相似文献
Beatrice S. BartlettEmail: |