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Introduction This study aimed to perform a preliminary validation of the Dental Clinical Learning Environment Instrument (DECLEI) in a Brazilian dental school. Material and methods Dental Clinical Learning Environment Instrument was translated into Brazilian-Portuguese, and Brazilian DECLEI's items relevance and content validity were assessed using the content validity index (CVI). DECLEI was then distributed to 155 Brazilian undergraduate dental students attending the 7th and 8th semester of dental studies. Principal Component Analysis (PCA) was used as an initial exploration of the Brazilian DECLEI's internal structure. Item-total correlations for the remaining items were calculated to identify items with poor discrimination coefficients. The internal consistency reliability for the final set of 17 items was calculated using Cronbach's alpha coefficient. The sensitivity of the instrument to measure differences between groups regarding year in dental school, race and sex was also assessed. Results The CVI was ≥0.80 for all 24 items of the Brazilian DECLEI indicating that all items were relevant to the local culture. Principal Components Analysis (PCA) provided evidence of a single dominant component containing 17 items (Cronbach's α = .86), and all 17 items met the benchmark of acceptable item-total correlation. Significant differences were found only when comparing 7th- and 8th-semester students. Conclusions Dental Clinical Learning Environment Instrument has the potential to be used as a reliable instrument to measure clinical learning environments for Brazilian dental students.

PURPOSES/OBJECTIVES Few tools assess the dental school clinical learning environment from students' perspectives. Considering previous efforts to validate the Dental Education Clinical Learning Instrument (DECLEI) in the United States, the goal of this study was to look for the fewest number of items that accounted for the most amount of variability in responses and/or had the highest correlation to the total DECLEI score using a larger, multi-center sample. METHODS The DECLEI was distributed to 286 students in two dental schools (University of Iowa and University of Texas at Houston) during the 2017-2018 academic year. Two alternative methods were applied. In the first approach, all 24-items were regressed on the total composite score using a forward conditional method. In the second approach, the item-total correlation for the full scale was calculated and then items with relatively poor coefficients were eliminated. A cutoff of 0.30 or less was used. RESULTS The first approach, Total R2 by Regression Model, produced a 9-item scale accounting for 90% of the variance in total score and a Cronbach's α coefficient of 0.79. The second approach, Item-Total Correlation, produced a larger scale (20 items), as well as a higher Cronbach's α coefficient of 0.89. The instrument also presented appropriate sensitivity to measure differences between race groups and school of origin. CONCLUSION DECLEI may have the potential to be used as an instrument to measure clinical learning environments for U.S. dental students using either a smaller, concise scale (Mini DECLEI-USA) or a larger (DECLEI-USA), more thorough scale.

Research on dental students' perceptions of clinical learning environments is needed to identify strengths, weaknesses, and need for interventions to sustain high-quality dental education, but a primary challenge has been the absence of an instrument designed to assess these perceptions. The Dental Clinical Learning Environment Instrument (DECLEI) is a new instrument developed specifically for dental clinical learning environments according to psychometric standards and validated in Europe. The aim of this study was to perform a preliminary validation of DECLEI in a U.S. dental school, thus providing data for subsequent validation in a larger, multi-institution sample. After five experienced faculty members assessed DECLEI's item relevance and content validity, the instrument was distributed in 2016 to 144 third- and fourth-year dental students at the University of Iowa College of Dentistry & Dental Clinics. All 144 questionnaires were completed (100% response rate). The results were tabulated and submitted to principal component analysis with an orthogonal rotation to assess internal structure of the measure. Internal consistency reliability was assessed using Cronbach's alpha coefficient and corrected item-total correlations. The results showed that, of the initial 24 items, principal component analysis allowed 18 items grouped in five domains: student-faculty interaction, equipment and patient issues, didactic-clinical components interaction, negative perceptions, and self-assessment. The Cronbach's alpha coefficients for these five domains ranged from 0.52 to 0.80. These results suggest that DECLEI has the potential for use as a reliable instrument to assess students' perceptions of clinical learning environments at U.S. dental schools, thus supporting the need for a definitive validation analysis in a larger sample.

Characterizing phenotypic differences between sexual and asexual organisms is a critical step towards understanding why sexual reproduction is so common. Because asexuals are often polyploid, understanding how ploidy influences phenotype is directly relevant to the study of sex and will provide key insights into the evolution of ploidy-level variation. The well-established association between genome size and cell cycle duration, evidence for a link between genome size and tissue regeneration rate and the growing body of research showing that ploidy influences growth rate and gene expression led us to hypothesize that healing and tissue regeneration might be affected by ploidy-level variation. We evaluated this hypothesis by measuring the rate of regeneration of antenna tissue of Potamopyrgus antipodarum , a New Zealand snail characterized by frequent coexistence between diploid sexuals and polyploid asexuals. Antennae of triploid and presumptive tetraploid asexuals regenerated more rapidly than the antennae of diploid sexuals, but regeneration rate did not differ between triploids and tetraploids. These results suggest either that ploidy elevation has nonlinear positive effects on tissue regeneration and/or that factors associated directly with reproductive mode affect regeneration rate more than ploidy level. The results of this study also indicate that the lower ploidy of sexual P. antipodarum is unlikely to confer advantages associated with more rapid regeneration.