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221.
The phylogenetic position of hyoliths has long been unsettled, with recent discoveries of a tentaculate feeding apparatus (‘lophophore’) and fleshy apical extensions from the shell (‘pedicle’) suggesting a lophophorate affinity. Here, we describe the first soft parts associated with the feeding apparatus of an orthothecid hyolith, Triplicatella opimus from the Chengjiang biota of South China. The tuft-like arrangement of the tentacles of T. opimus differs from that of hyolithids, suggesting they collected food directly from the substrate. A reassessment of the feeding organ in hyolithids indicates that it does not represent a lophophore and our analysis of the apical structures associated with some orthothecids show that these represent crushed portions of the shell and are not comparable to the brachiopod pedicle. The new information suggests that hyoliths are more likely to be basal members of the lophotrochozoans rather than lophophorates closely linked with the Phylum Brachiopoda.  相似文献   
222.
The aims of this study were to evaluate the accuracy of centre of pressure (COP) data obtained during transition of load across the boundary between two force plates, and secondly to examine the effect of such COP data on joint kinetics during sprint running performances. COP data were collected from two piezoelectric force plates as a trolley wheel was rolled across the boundary between the plates. Position data for the trolley were collected using an opto-electronic motion analysis system for comparison with COP data. Mean COP errors during transition across the plate boundary were 0.003 ± 0.002 m relative to a control point. Kinematic and kinetic data were also collected from eight athletes during sprint running trials to demonstrate the sensitivity of the inverse dynamics analysis to COP error for the ground contact phase of the dynamic movement trials. Kinetic sensitivity to the COP error was assessed during the entire stance phase for the ankle, knee, and hip joints and was less than 5% and 3% for joint moment and power data, respectively. Based on the small COP error during transition across plate boundaries, it is recommended that foot contacts overlapping two force plates may be included in inverse dynamics analyses.  相似文献   
223.
Railway transitions experience differential movements due to differences in track system stiffness, track damping characteristics, foundation type, ballast settlement from fouling and/or degradation, as well as fill and subgrade settlement. This differential movement is especially problematic for high speed rail infrastructure as the ??bump?? at the transition is accentuated at high speeds. Identification of different factors contributing towards this differential movement, as well as development of design and maintenance strategies to mitigate the problem is imperative for the safe and economical operation of both freight and passenger rail networks. This paper presents the research framework and initial instrumentation details from an ongoing research effort at the University of Illinois at Urbana-Champaign. Three bridge approaches experiencing recurrent geometry problems were instrumented using multidepth deflectometers (MDDs) and strain gages to identify different factors contributing to the development of differential movements.  相似文献   
224.
Many college counseling centers do not collect client data at each session because of perceived burdens. This study explored 55 clients’ and 16 doctoral counselor trainees’ experiences collecting and using data on client distress at each session over the course of counseling at a large public university's counseling center. Results indicated that the majority of both clients and counselors found the process convenient and clinically useful. Findings, clinical implications, and future directions are discussed.  相似文献   
225.
While participation in the activities like bondage, domination, submission/sadism, masochism that fall under the umbrella term BDSM is widespread, stigma surrounding BDSM poses risks to practitioners who wish to disclose their interest. We examined risk factors involved with disclosure to posit how sex education might diffuse stigma and warn of risks. Semi-structured interviews asked 20 adults reporting an interest in BDSM about their disclosure experiences. Most respondents reported their BDSM interests starting before age 15, sometimes creating a phase of anxiety and shame in the absence of reassuring information. As adults, respondents often considered BDSM central to their sexuality, thus disclosure was integral to dating. Disclosure decisions in nondating situations were often complex considerations balancing desire for appropriateness with a desire for connection and honesty. Some respondents wondered whether their interests being found out would jeopardize their jobs. Experiences with stigma varied widely.  相似文献   
226.
This mixed-methods study explores differences in novice and experienced undergraduate students' perceptions of their cognitive, personal, and professional gains from engaging in scientific research. The study was conducted in four different undergraduate research (UR) programs at two research-extensive universities; three of these programs had a focus on the biosciences. Seventy-three entry-level and experienced student researchers participated in in-depth, semi-structured interviews and completed the quantitative Undergraduate Research Student Self-Assessment (URSSA) instrument. Interviews and surveys assessed students' developmental outcomes from engaging in UR. Experienced students reported distinct personal, professional, and cognitive outcomes relative to their novice peers, including a more sophisticated understanding of the process of scientific research. Students also described the trajectories by which they developed not only the intellectual skills necessary to advance in science, but also the behaviors and temperament necessary to be a scientist. The findings suggest that students benefit from multi-year UR experiences. Implications for UR program design, advising practices, and funding structures are discussed.  相似文献   
227.
Flipped classrooms represent a new instructional paradigm for presenting K-12 instruction. Whereas in traditional classrooms new content is taught during the school day and application activities are assigned for homework, in flipped classrooms students are expected to acquire new content by working through assigned tasks at home prior to the next day’s class. Subsequently, class time is used for application activities. To date, limited, conflicting analyses of research about the efficacy of the flipped classroom paradigm have been reported. This lack of a clear consensus is of concern for students with serious learning and/or behavioural challenges who have not been the focus of these analyses and whose learning characteristics arguably run counter to what students must do to be successful in flipped classrooms. The investigation reported herein addresses one aspect of the aforementioned void in the literature. Data from an international survey of teacher educators from 33 countries that ascertained their thoughts about the appropriateness of the flipped classroom paradigm for students with serious learning and/or behavioural challenges are reported. Results indicate that teacher educators have reservations about the appropriateness of flipped classrooms, but that their opinions are not fully informed by knowledge about, and experience with, these classrooms.  相似文献   
228.
The current study examined the effects of stress and campus climate perceptions on the persistence decisions of students of color and White students using Bean and Eaton’s (2000) Psychological Model of College Student Retention. A sample of first-year students (N = 1,491) at a predominantly White research university were survey enduring their second semester and their enrollment status was subsequently tracked after 2 years. Path analysis was conducted on the sample of students of color (n = 548) and White students (n = 943). Results indicated models that explained 27 % of the variance for students of color and 44 % of the variance for White students in persistence after 2 years of college. Among the initial 37 variables included in the models, 17 had significant direct and indirect effects on students’ of color persistence including observing racism on campus, having comfortable academic interactions, stress related to the academic environment, and feelings about the campus environment. For White students, 13 variables had significant direct and indirect effects on persistence, including having opportunities for diverse peer interactions and comfortable academic interactions, stress related to the social environment on campus, and feelings about the campus environment. The discussion highlights the usefulness of the Bean and Eaton model for examining retention for students of color and White students.  相似文献   
229.
Student evaluations of teaching are ubiquitous and impactful on the careers of college teachers. However, there is limited empirical research documenting the accuracy of people’s efforts in interpreting teaching evaluations. The current research consisted of three studies documenting the effect of small mean differences in teaching evaluations on judgements about teachers. Differences in means small enough to be within the margin of error significantly impacted faculty members’ assignment of merit-based rewards (Study 1), department heads’ evaluation of teaching techniques (Study 2) and faculty members’ evaluation of specific teaching skills (Study 3). The results suggest that faculty and administrators do not apply appropriate statistical principles when evaluating teaching evaluations and instead use a general heuristic that higher evaluations are better.  相似文献   
230.
Faculty frequently express concerns about students’ personal use of information and communication technologies in today’s university classrooms. As a requirement of a graduate research methodology course in a university in Ontario, Canada, the authors conducted qualitative research to gain an in-depth understanding of students’ perceptions of this issue. Their findings reveal students’ complex considerations about the acceptability of technology use. Their analysis of the broader contexts of students’ use reveals that despite a technological revolution, university teaching practices have remained largely the same, resulting in ‘cultural lag’ within the classroom. While faculty are technically ‘in charge’, students wield power through course evaluations, surveillance technologies and Internet postings. Neoliberalism and the corporatisation of the university have engendered an ‘entrepreneurial student’ customer who sees education as a means to a career. Understanding students’ perceptions and their technological, social and political contexts offers insights into the tensions within today’s classrooms.  相似文献   
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