A wide range of occupations require science, technology, engineering, and mathematics (STEM) skills, yet almost half of students who intend to pursue a postsecondary STEM education abandon these ...plans before graduating from college. This attrition is especially pronounced among underrepresented groups (i.e., racial/ethnic minorities and first-generation college students). We conducted a 2-year follow-up of a utility-value intervention that had been implemented in an introductory biology course. This intervention was previously shown to improve performance in the course, on average and especially among underrepresented students, reducing the achievement gap. The goal of the present study was to examine whether the intervention also impacted persistence in the biomedical track throughout college. The intervention had a more positive impact on long-term persistence for students who were more confident that they could succeed at the beginning of the course, and this effect was partially driven by the extent to which students reflected on the personal relevance of biological topics in their essays. This mechanism was distinct from the process that had been found to underlie intervention effects on performance-engagement with course material-suggesting that utility-value interventions may affect different academic outcomes by initiating distinct psychological processes. Although we did not find that the intervention was differentially effective for underrepresented students in terms of persistence, we found that positive effects on performance were associated with increased persistence for these students. Results suggest that utility-value interventions in an introductory course can be an effective strategy to promote persistence in the biomedical sciences throughout college.
Educational Impact and Implications Statement
We conducted a 2-year follow-up study of a utility-value intervention (UVI) in which students wrote about the personal value of course topics in an introductory biology course for biomedical majors, and examined persistence in terms of subsequent course-taking and whether students were biomedical majors. The original study found that the UVI improved course grades for all students, on average, as well as for underrepresented students, by promoting engagement with intervention writing assignments. In the current follow-up, we found that the UVI indirectly increased persistence through the original effects on course grades, for all students on average and for underrepresented students in particular: better course grades were associated with higher levels of persistence. In addition, we found that among students who received the UVI, those who were more confident that they could succeed in the course were more likely to persist in a biomedical education 2 years later, an effect explained by increased focus on personal relevance in students' biology writing assignments. This study has important implications for college science educators who seek to retain their students and promote diversity in the biomedical sciences.
Despite efforts to attract and maintain diverse students in the science, technology, engineering, and math (STEM) pipeline, issues with attrition from undergraduate STEM majors persist. The aim of ...this study was to examine how undergraduate science students’ competence beliefs, task values, and perceived costs in science combine into motivational profiles and to consider how such profiles relate to short‐term and long‐term persistence outcomes in STEM. We also examined the relations between underrepresented group membership and profile membership. Using latent profile analysis, we identified three profiles that characterized 600 participants’ motivation during their first semester in college: Moderate All, Very High Competence/Values‐Low Effort Cost, and High Competence/Values‐Moderate Low Costs. The Moderate All profile was associated with the completion of fewer STEM courses and lower STEM grade point averages relative to the other profiles after 1 and 4 years of college. Furthermore, underrepresented minority students were overrepresented in the Moderate All profile. Findings contribute to our understanding of how science competence beliefs, task values, and perceived costs may coexist and what combinations of these variables may be adaptive or deleterious for STEM persistence and achievement.
"Social psychological research on gendered persistence in science, technology, engineering, and mathematics (STEM) professions is dominated by two explanations: women leave because they perceive ...their family plans to be at odds with demands of STEM careers, and women leave due to low self-assessment of their skills in STEM's intellectual tasks, net of their performance. This study uses original panel data to examine behavioral and intentional persistence among students who enter an engineering major in college. Surprisingly, family plans do not contribute to women's attrition during college but are negatively associated with men's intentions to pursue an engineering career. Additionally, math self-assessment does not predict behavioral or intentional persistence once students enroll in a STEM major. This study introduces professional role confidence -- individuals' confidence in their ability to successfully fulfill the roles, competencies, and identity features of a profession -- and argues that women's lack of this confidence, compared to men, reduces their likelihood of remaining in engineering majors and careers. We find that professional role confidence predicts behavioral and intentional persistence, and that women's relative lack of this confidence contributes to their attrition." (Author's abstract, IAB-Doku). Die Untersuchung enthält quantitative Daten. Forschungsmethode: empirisch-quantitativ; empirisch; Längsschnitt. Die Untersuchung bezieht sich auf den Zeitraum 2003 bis 2007.
Prominent theoretical accounts of attention-deficit/hyperactivity-disorder (ADHD) hypothesize that reinforcement learning deficits underlie symptoms of ADHD. The Dynamic Developmental Theory and the ...Dopamine Transfer Deficit hypothesis assume impairments in both the acquisition and extinction of behavior, especially when learning occurs under partial (non-continuous) reinforcement, and subsequently the Partial Reinforcement Extinction Effect (PREE). Few studies have evaluated instrumental learning in ADHD and the results are inconsistent. The current study investigates instrumental learning under partial and continuous reinforcement schedules and subsequent behavioral persistence when reinforcement is withheld (extinction) in children with and without ADHD.
Large well-defined samples of children with ADHD (n = 93) and typically developing (TD) children (n = 73) completed a simple instrumental learning task. The children completed acquisition under continuous (100%) or partial (20%) reinforcement, followed by a 4-min extinction phase. Two-way (diagnosis by condition) ANOVAs evaluated responses needed to reach the learning criterion during acquisition, and target and total responses during extinction.
Children with ADHD required more trials to reach criterion compared to TD children under both continuous and partial reinforcement. After partial reinforcement, children with ADHD executed fewer target responses during extinction than TD children. Children with ADHD executed more responses than TD children during extinction, irrespective of learning condition.
The findings demonstrate general difficulties in instrumental learning in ADHD, that is, slower learning irrespective of reinforcement schedule. They also show faster extinction following learning under partial reinforcement in those with ADHD, that is, a diminished PREE. Children with ADHD executed more responses during extinction. Results are theoretically important, with clinical implications for understanding and managing learning difficulties in those with ADHD, as they suggest poorer reinforcement learning and lower behavioral persistence.
Biofilms on dry hospital surfaces can enhance the persistence of micro-organisms on dry harsh clinical surfaces and can potentially act as reservoirs of infectious agents on contaminated surfaces.
...This study was conducted to quantify the transfer of viable Staphylococcus aureus cells from dry biofilms through touching and to investigate the impact of nutrient and moisture deprivation on virulence levels in S. aureus.
Dry biofilms of S. aureus ATCC 25923 and a defective biofilm-forming ability mutant, S. aureus 1132, were formed in 24-well plates under optimized conditions mimicking dry biofilm formation on clinical surfaces. Microbial cell transfer was induced through the touching of the dry biofilms, which were quantified on nutrient agar. To investigate the impact of nutrient and moisture deprivation on virulence levels, dry and standard biofilms as well as planktonic cells of S. aureus ATCC 25923 were inoculated into Galleria mellonella and their kill rates compared.
Results of this study showed that viable cells from dry biofilms of S. aureus ATCC 25923 were significantly more virulent and readily transferrable from dry biofilms through a touch test, therefore representing a greater risk of infection. The biofilm-forming capability of S. aureus strains had no significant impact on their transferability with more cells transferring when biofilm surfaces were wet.
These findings indicate that dry biofilms on hospital surfaces may serve as a reservoir for the dissemination of pathogenic micro-organisms in hospitals, thus highlighting the importance of regular cleaning and adequate disinfection of hospital surfaces.
Through both casework and research, fibres have been found to have the particularly useful ability to persist and remain exploitable after submersion. However, direct analysis of the persistence ...ability remains in early stages, and in particular, submersion times above a day have not been thoroughly studied. This study aims to both extend understanding of the impact of flow rate and submersion periods of up to 28 days. A blended polyester/cotton green fabric was abraded to increase transfer and then dragged over a black cotton substrate. Six replicates of these substrates were then submerged in artificial flow cells at various flow rates for 28 days. These were illuminated under UV light and photographed prior to submersion, at set times during submersion and after submersion. Another set of six replicates were imaged, submerged into a river and then recovered and re-imaged after 28 days. The population of fibres was then counted using these photographs, and a mix of one-way and two-way ANOVA tests were applied, in combination with Tukey’s HSD, to detect significant differences across time and flow rate categories. Loss predominantly occurred on within the first 24 hours, in agreement with previous work. However, distinct from previous work there was a slow, approximately logarithmic loss over the balance of the submersion period. While significant differences were found between flow categories, there was no clear relationship between flow rate and persistence. The behaviour of the river samples was well-predicted by laboratory samples. 100 % fibre loss was never observed, with the maximum instead being 95.45 %. These results extend the understanding of fibre persistence on submerged substrates beyond the short submersion times in previous literature, and provide some deeper understanding of the impact of flow rate.
Duckworth, Peterson, Matthews, and Kelly (2007) defined grit as one's passion and perseverance toward long-term goals. They proposed that it consists of 2 components: consistency of interests and ...perseverance of effort. In a high school and college student sample, we used a multidimensional item response theory approach to examine (a) the factor structure of grit, and (b) grit's relations to and overlap with conceptually and operationally similar constructs in the personality, self-regulation, and engagement literatures, including self-control, conscientiousness, cognitive self-regulation, effort regulation, behavioral engagement, and behavioral disaffection. A series of multiple regression analyses with factor scores was used to examine (c) grit's prediction of end-of-semester course grades. Findings indicated that grit's factor structure differed to some degree across high school and college students. Students' grit overlapped empirically with their concurrently reported self-control, self-regulation, and engagement. Students' perseverance of effort (but not their consistency of interests) predicted their later grades, although other self-regulation and engagement variables were stronger predictors of students' grades than was grit.
Persistent homology is a recently developed theory in the field of algebraic topology to study shapes of datasets. It is an effective data analysis tool that is robust to noise and has been widely ...applied. We demonstrate a general pipeline to apply persistent homology to study time series, particularly the instantaneous heart rate time series for the heart rate variability (HRV) analysis. The first step is capturing the shapes of time series from two different aspects-the persistent homologies and hence persistence diagrams of its sub-level set and Taken's lag map. Second, we propose a systematic and computationally efficient approach to summarize persistence diagrams, which we coined
. To demonstrate our proposed method, we apply these tools to the HRV analysis and the sleep-wake, REM-NREM (rapid eyeball movement and non rapid eyeball movement) and sleep-REM-NREM classification problems. The proposed algorithm is evaluated on three different datasets via the cross-database validation scheme. The performance of our approach is better than the state-of-the-art algorithms, and the result is consistent throughout different datasets.
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