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Institution

University of North Carolina at Charlotte

EducationCharlotte, North Carolina, United States
About: University of North Carolina at Charlotte is a education organization based out in Charlotte, North Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 8772 authors who have published 22239 publications receiving 562529 citations. The organization is also known as: UNC Charlotte & UNCC.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a weighted Nadaraya-Watson (WNW) estimator of conditional distribution function was used for regression quantiles for α-mixing time series at both boundary and interior points, and the WNW conditional distribution estimator not only preserves the bias, variance and, more important, automatic good boundary behavior properties of local linear estimators introduced by Yu and Jones (1998, Journal of the American Statistical Association 93, 228-237), but also has the additional advantage of always being a distribution itself.
Abstract: In this paper we study nonparametric estimation of regression quantiles for time series data by inverting a weighted Nadaraya–Watson (WNW) estimator of conditional distribution function, which was first used by Hall, Wolff, and Yao (1999, Journal of the American Statistical Association 94, 154–163). First, under some regularity conditions, we establish the asymptotic normality and weak consistency of the WNW conditional distribution estimator for α-mixing time series at both boundary and interior points, and we show that the WNW conditional distribution estimator not only preserves the bias, variance, and, more important, automatic good boundary behavior properties of local linear “double-kernel” estimators introduced by Yu and Jones (1998, Journal of the American Statistical Association 93, 228–237), but also has the additional advantage of always being a distribution itself. Second, it is shown that under some regularity conditions, the WNW conditional quantile estimator is weakly consistent and normally distributed and that it inherits all good properties from the WNW conditional distribution estimator. A small simulation study is carried out to illustrate the performance of the estimates, and a real example is also used to demonstrate the methodology.

192 citations

Journal ArticleDOI
TL;DR: In this study, student perception on the helpfulness of the twelve different facilitation strategies used by instructors on establishing instructor presence, instructor connection, engagement and learning is examined.
Abstract: Instructors use various strategies to facilitate learning and actively engage students in online courses. In this study, we examine student perception on the helpfulness of the twelve different facilitation strategies used by instructors on establishing instructor presence, instructor connection, engagement and learning. One hundred and eighty eight graduate students taking online courses in Fall 2016 semester in US higher education institutions responded to the survey. Among the 12 facilitation strategies, instructors' timely response to questions and instructors' timely feedback on assignments/projects were rated the highest in all four constructs (instructor presence, instructor connection, engagement and learning). Interactive visual syllabi of the course was rated the lowest, and video based introduction and instructors' use of synchronous sessions to interact were rated lowest among two of the four constructs. Descriptive statistics for each of the construct (instructor presence, instructor connection, engagement and learning) by gender, status, and major of study are presented. Confirmative factor analysis of the data provided aspects of construct validity of the survey. Analysis of variance failed to detect differences between gender and discipline (education major versus non-education major) on all four constructs measured. However, undergraduate students rated significantly lower on engagement and learning in comparison to post-doctoral and other post graduate students.

192 citations

Journal ArticleDOI
TL;DR: In this article, a coherent coupling between surface plasmon polaritons (SPP) and quantum well excitons in a hybrid metal-semiconductor nanostructure is reported.
Abstract: We report measurements of a coherent coupling between surface plasmon polaritons (SPP) and quantum well excitons in a hybrid metal-semiconductor nanostructure. The hybrid structure is designed to optimize the radiative exciton-SPP interaction which is probed by low-temperature, angle-resolved, far-field reflectivity spectroscopy. As a result of the coupling, a significant shift of $\ensuremath{\sim}7\text{ }\text{ }\mathrm{meV}$ and an increase in broadening by $\ensuremath{\sim}4\text{ }\text{ }\mathrm{meV}$ of the quantum well exciton resonance are observed. The experiments are corroborated by a phenomenological coupled-oscillator model predicting coupling strengths as large as 50 meV in structures with optimized detunings between the coupled exciton and SPP resonances. Such a strong interaction can, e.g., be used to enhance the luminescence yield of semiconductor quantum structures or to amplify SPP waves.

191 citations

Journal ArticleDOI
TL;DR: Techniques developed to model and estimate task specific uncertainty for coordinate measuring systems, primarily coordinate measuring machines using contacting probes are surveyed.

191 citations

Journal ArticleDOI
TL;DR: Examination of the role of the dormant-like viable but nonculturable (VBNC) condition in the etiology of bacterial infection provided evidence that the VBNC state may be involved in explaining the persistent nature of some infections.
Abstract: The role of the dormant-like viable but nonculturable (VBNC) condition in the etiology of bacterial infection was examined using a plant system. The plant-pathogenic bacterium Ralstonia solanacearum was first shown to enter into the VBNC state both in response to cupric sulfate when in a saline solution and when placed in autoclaved soil. To determine if the VBNC condition is related to pathogenesis, the physiological status of bacteria recovered from different regions of inoculated tomato plants was determined at different stages of infection. The fraction of in planta bacteria that were VBNC increased during infection and became greater than 99% by the late stage of disease. The possibility that soil-dwelling VBNC bacteria may resuscitate and infect plants was also examined. When tomato seeds were germinated in sterile soil that contained VBNC but no detectable culturable forms of R. solanacearum cells, resuscitation was observed to occur in soil adjacent to plant roots; these resuscitated bacteria were able to infect plants. This is the first report of R. solanacearum entering the VBNC state and of resuscitation of any VBNC plant-pathogenic bacteria and provides evidence that the VBNC state may be involved in explaining the persistent nature of some infections.

191 citations


Authors

Showing all 8936 results

NameH-indexPapersCitations
Chao Zhang127311984711
E. Magnus Ohman12462268976
Staffan Kjelleberg11442544414
Kenneth L. Davis11362261120
David Wilson10275749388
Michael Bauer100105256841
David A. B. Miller9670238717
Ashutosh Chilkoti9541432241
Chi-Wang Shu9352956205
Gang Li9348668181
Tiefu Zhao9059336856
Juan Carlos García-Pagán9034825573
Denise C. Park8826733158
Santosh Kumar80119629391
Chen Chen7685324974
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202361
2022231
20211,470
20201,561
20191,489
20181,318