Is passive drag dependent on the interaction of kayak design and paddler weight in flat-water kayaking?

Abstract

Drag is one of the major factors that influences kayaking performance. To focus on the drag of the kayak’s hull shape and the paddlers’ weight per se, the passive drag (D_p) was measured on a flat-water sprint course for one paddler with added weights. D_p was measured by an electromechanical towing device using a load cell, at incremental and constant velocities from 2.78 to 5.56 m/s. Three kayaks of different sizes and shapes (Nelo® K1 Quattro-M, ML, and L) were used and the paddlers’ body weight was adjusted with weights so the total paddler weight in the kayak was 65, 75, and 85 kg. The mean D_p increased by the power function of D = kvⁿ (mean R² = .990; SD .006). The D_p went from 21.37?±?1.29 N at 2.78 m/s to 89.32?±?6.43 N at 5.56 m/s. For the two lighter weighted kayaks (65 and 75 kg), the lowest D_p was observed with different kayak sizes (M, ML, or L) depending on the target velocity. The manufacturers suggest that paddlers should select a kayak size according to their body weight to minimise drag; however, the results of this study suggest that target velocities, and thus competition distance should also be factored into kayak selection.     

A Hard Look at Ourselves: A Reception Study of Rhetoric of Science

This study traces the reception of rhetoric of science work in book reviews by science studies scholars, focusing particularly on critiques of the author's own book by historians of science, to ground recommendations for improving our status in the interdisciplinary conversation. In describing the work of other science studies scholars, rhetoricians of science should acknowledge the rhetorical contributions of nonrhetoricians and negotiate a shared space rather than attempt to fill perceived lacunae in the literature.     

Predicting acceptance of diversity in pre-kindergarten classrooms

This study examined classroom-level contributors to an acceptance of diversity in publicly supported pre-kindergarten classrooms across 11 states. Classroom composition, process quality, and teacher characteristics were examined as predictors of diversity-promoting practices as measured by the ECERS-R, acceptance of diversity construct. Findings reveal that emotional climate, bilingual classrooms, family poverty levels within classrooms, and Latino teacher ethnicity are predictive of diversity-promoting classrooms; while classroom-level ethnic sameness to teacher prohibits diversity-promoting practices in pre-kindergarten classrooms.     

Bioinformatics Education in High School: Implications for Promoting Science,Technology, Engineering,and Mathematics Careers

We investigated the effects of our Bio-ITEST teacher professional development model and bioinformatics curricula on cognitive traits (awareness, engagement, self-efficacy, and relevance) in high school teachers and students that are known to accompany a developing interest in science, technology, engineering, and mathematics (STEM) careers. The program included best practices in adult education and diverse resources to empower teachers to integrate STEM career information into their classrooms. The introductory unit, Using Bioinformatics: Genetic Testing, uses bioinformatics to teach basic concepts in genetics and molecular biology, and the advanced unit, Using Bioinformatics: Genetic Research, utilizes bioinformatics to study evolution and support student research with DNA barcoding. Pre–post surveys demonstrated significant growth (n = 24) among teachers in their preparation to teach the curricula and infuse career awareness into their classes, and these gains were sustained through the end of the academic year. Introductory unit students (n = 289) showed significant gains in awareness, relevance, and self-efficacy. While these students did not show significant gains in engagement, advanced unit students (n = 41) showed gains in all four cognitive areas. Lessons learned during Bio-ITEST are explored in the context of recommendations for other programs that wish to increase student interest in STEM careers.     

Being First Means Being Credible? Examining the Impact of Message Source on Organizational Reputation

Research in organizational communication and public relations suggest that in times of crises, messages generated by the organization are most likely to positively influence stakeholder perceptions, whereas those generated by the press may have negative ramifications. Although this advice seems logical, to date there is little research that investigates this claim empirically and directly. Two experiments were conducted to explore the separate and combined impact of print and televised messages concerning an organization in the midst of a crisis. The findings offer empirical evidence that statements from organizations experiencing crises may offset negative stakeholder responses. Theoretical and pragmatic implications are discussed regarding these findings.     

Information sources and voting in a primary and general election

There is a considerable variance in audience perceptions of media use and credibility between primary and general elections. The authors are in the School of Journalism and the Department of Speech, respectively, at Southern Illinois University, Carbondale. They gratefully acknowledge the assistance of Drs. Robert 0. Hirsch and Larry Kokkeler in the collection of data for this report.     

Contributions Of Teachers To Dental Health Knowledge And Behavior Of Students

For the K-sample Siegel-Tukey and Klotz tests on variance, Penfield and Koffler published, in this journal, test-statistic formulas that yield excessively liberal tests. The degree of liberalness is demonstrated, and corrected formulas are presented and illustrated in this paper.     

Emerging Adult Siblings' Use of Verbally Aggressive Messages as Hurtful Messages

The purpose of this study was to identify the specific types of verbally aggressive messages emerging adult siblings use with each other and to determine whether these types of verbally aggressive messages differ in perceived hurtfulness, intensity, and intent. Participants were 115 individuals who identified a verbally aggressive message recently used by a sibling. Results indicated that siblings use seven types of verbally aggressive messages (i.e., name calling, insults, withdrawal, physical acts or threats, repudiating the relationship, negative affect, unfair comparison), and the seven types of verbally aggressive messages do not differ in their perceived hurtfulness, intensity, and intent.