Peers' Emotionality and Children's Academic Achievement in Second Grade: Testing the Moderating Role of Children's Behavioral Self-Regulation

Although there is interest in the role of peers in children's schooling experiences, few researchers have examined associations and related underlying processes between peers' emotionality, an aspect of temperament, and children's academic achievement. This study evaluated whether target children's (N = 260) own self-regulation, assessed with two behavioral measures, served a moderating function for associations between peers' emotionality and children's own academic achievement in second grade. There was a positive association between peers' positive emotionality and reading scores for children with higher self-regulation. Peers' negative emotionality was negatively related to target children's reading scores, particularly for children with higher self-regulation levels, but was unrelated to math scores. Peers' positive and negative emotionality did not predict math scores, and there was no strong evidence for the moderating role of target children's self-regulation in this association. This study highlights the potential role of children's self-regulation in modulating peer effects on academic achievement, particularly reading.

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species-in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec's PRISM mode9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10-12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.

Longitudinal relations between behavioral engagement and academic achievement: The moderating roles of socio-economic status and early achievement

This study investigated developmental trajectories of observationally coded engagement across the early elementary years and whether these trajectories were associated with children's academic achievement. Furthermore, we evaluated if these relations varied as a function of children's family socio-economic status and early reading and math skills. Data were collected from 301 children who were studied from kindergarten (Mage = 65.74 months; 49% boys) to 2nd grade. Children's behavioral engagement was observed in kindergarten, 1st, and 2nd grade. Reading and math skills were assessed via standardized tests in kindergarten and 2nd grade. Growth mixture models identified two classes of behavioral engagement: most children (87.0%) displayed relatively high behavioral engagement in the fall of kindergarten and decreased significantly across time (referred to below as high-decreasing class), and other children (13.0%) exhibited moderate behavioral engagement in the fall of kindergarten that was stable across time (referred to below as moderate-stable class). After controlling for academic skills in kindergarten and demographic variables (i.e., child age, sex, ethnicity, and family socio-economic status), children in the high-decreasing class displayed higher reading skills, but not math skills, than children in the moderate-stable class. Additional analyses revealed that differences in reading skills between the two classes were present only for children from low socio-economic status families or for children low in kindergarten reading skills. The findings suggest that economically or academically at-risk students might benefit more than their peers from high behavioral engagement.

Similarities and differences between actigraphy and parent-reported sleep in a Hispanic and non-Hispanic White sample

OBJECTIVE

Despite concerns about the inaccuracy of parents' reports of children's sleep, it remains unclear whether the bias of parents' reports varies across racial/ethnic groups. To address this limitation, the current study systematically investigated the concordance among parent-reported sleep questionnaires, sleep diaries, and actigraphy-based sleep in a sample of Hispanic and non-Hispanic White children.

METHODS

Parents of 51 Hispanic and 38 non-Hispanic White children (N = 89; M_age = 6.46, SD = 0.62; 50.6% male) reported their child's bedtime and wake time on school days using sleep diaries and questionnaires. Children's sleep also was assessed with actigraphy for five consecutive school days.

RESULTS

Parents reported longer sleep duration, earlier bedtime, and later wake time using sleep diaries and questionnaires compared to actigraphy-based assessments. Larger discrepancies between diaries and actigraphy of sleep duration, and between questionnaires and actigraphy of wake time were found in non-Hispanic White children, compared to Hispanic children.

CONCLUSIONS

Although parents tended to overestimate their child's sleep as compared to actigraphy, parents of Hispanic children may be more accurate in some estimates of children's sleep than parents of non-Hispanic White children. Researchers, clinicians, and parents should be aware of the potential biases in parents' reports and estimates of their child's sleep and that the degree of bias could vary across racial/ethnic groups.

Effortful Control and Extensive Observations of Negative Emotion as Joint Predictors of Teacher-Student Conflict in Childhood

Studies with extensive observations of real-life emotions at school are rare but might be especially useful for predicting school-related outcomes. This study evaluated observations of negative emotion expressivity in lunch and recreation settings across kindergarten, first grade, and second grade (N = 301), kindergarten teachers' reports of children's effortful control, and kindergarten and second grade teachers' reports of their perceived conflict with children. In latent growth curve analyses, we tested whether individual trajectories of negative expressivity from kindergarten to second grade, based on estimated slopes, predicted teacher-student conflict in second grade, and whether effortful control in kindergarten moderated this association.

RESEARCH FINDINGS

Negative expressivity levels in kindergarten significantly predicted higher levels of teacher-student conflict in second grade, controlling prior teacher-student conflict. Furthermore, greater increases in negative expressivity from kindergarten to second grade were associated with higher teacher-student conflict in second grade especially for children who had difficulties with effortful control in kindergarten.

PRACTICE OR POLICY

Results from this study have the potential to inform programs focused on reducing teacher-student conflict. The findings highlight the possibility of targeting both effortful control and negative emotion in the early elementary school transition as a means to improve teacher-student relationships.

The association between home chaos and academic achievement: The moderating role of sleep

The goal of this study was to understand the role young children's sleep plays in the association between their family environment and academic achievement (AA) by examining sleep as a moderator between home chaos (chaos) and children's AA. We examined this question in a sample of 103 kindergarteners and 1st graders. In the fall, parents reported on levels of chaos in their home. To measure sleep, early in the spring, children wore actigraphs for 5 consecutive school nights. Later in the spring, children completed standardized tests of achievement. Sleep duration, but not sleep efficiency, moderated relations between chaos and AA. Specifically, children with longer sleep durations (26% of the sample), compared to children with average or lower sleep durations, had significant negative associations between chaos and achievement, indicating that children in higher chaos homes had lower academic achievement. The findings enhance scholars' understanding of the relation between chaos and AA as well as highlight an important bioregulatory factor in the association between home family environment and children's academic outcomes. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Prediction of Children's Early Academic Adjustment from Their Temperament: The Moderating Role of Peer Temperament

The goal of the study was to examine whether target children's temperamental negative emotional expressivity (NEE) and effortful control in the fall of kindergarten predicted academic adjustment in the spring and whether a classmate's NEE and effortful control moderated these relations. Target children's NEE and effortful control were measured in the fall via multiple methods, academic adjustment was measured via reading and math standardized tests in the spring, and observations of engagement in the classroom were conducted throughout the year. In the fall, teachers nominated a peer with whom each target child spent the most time and rated that peer's temperament. Target children with high effortful control had high reading and math achievement (ps = .04 and < .001, respectively), and children with low NEE increased in engagement during the year (p < .001). Peers' temperament did not have a direct relation to target children's academic adjustment. Peers' negative emotion, however, moderated the relation between target children's effortful control, as well as NEE, and changes in engagement (ps = .03 and .05, respectively). Further, peers' effortful control moderated the relations between target children's NEE and reading and changes in engagement (ps = .02 and .04, respectively). In each case, target children's temperament predicted the outcome in expected directions more strongly when peers had low NEE or high effortful control. Results are discussed in terms of how children's temperamental qualities relate to academic adjustment, and how the relation between NEE and changes in engagement, in particular, depends on peers' temperament.

Emotions in school and symptoms of psychological maladjustment from kindergarten to first grade

The associations between children's (N = 301) observed expression of positive and negative emotion in school and symptoms of psychological maladjustment (i.e., depressive and externalizing symptoms) were examined from kindergarten to first grade. Positive and negative emotional expressivity levels were observed in school settings, and teachers reported on measures of children's externalizing and depressive symptoms. In longitudinal panel models testing bidirectional paths, depressive symptoms in kindergarten were negatively associated with positive expressivity in first grade but not vice versa. Children's externalizing symptoms in kindergarten predicted higher negative expressivity in school in first grade. There was also significant prediction of externalizing in first grade by negative expressivity during kindergarten. Implications about child psychological maladjustment in early schooling are discussed.

Self-Regulation and Academic Measures Across the Early Elementary School Grades: Examining Longitudinal and Bidirectional Associations

This study evaluated the association between children's (N = 301) self-regulation and math and reading achievement in kindergarten, first grade, and second grade. Children's self-regulation was assessed using the Head-Toes-Knees-Shoulders (HTKS) task (involving control of gross body movements) and a computerized continuous performance task (CPT; assessing primarily inhibitory control) in kindergarten, first grade, and second grade. Research findings: Based on cross-lagged structural equation panel models, HTKS task performance positively predicted later math and reading achievement. Math achievement significantly and positively predicted later HTKS and CPT scores. Earlier math and reading achievement moderated the association between CPT scores and later math and reading achievement; inhibitory control-based self-regulation assessed with the CPT predicted higher math or reading achievement in subsequent grades for children with lower math or reading achievement in prior grades. Performance on the CPT moderated the paths from HTKS scores to later reading achievement; behavioral self-regulation assessed with the HTKS task predicted higher reading achievement in subsequent grades for children with low or average CPT performance in prior grades. Practice: Results from this study have the potential to inform targeted academic interventions focused on enhancing self-regulation in school contexts. The findings highlight the utility of assessing multiple measures of self-regulation.

Trajectories of the Expression of Negative Emotion from Kindergarten to First Grade: Associations with Academic Outcomes

We examined individual trajectories, across four time points, of children's (N = 301) expression of negative emotion in classroom settings and whether these trajectories predicted their observed school engagement, teacher-reported academic skills, and passage comprehension assessed with a standardized measure in first grade. In latent growth curve analyses, negative expressivity declined from kindergarten to first grade with significant individual differences in trajectories. Negative expressivity in kindergarten inversely predicted first grade school engagement and teacher-reported academic skills, and the slope of negative expressivity from kindergarten to first grade inversely predicted school engagement (e.g., increasing negative expressivity was associated with lower school engagement). In addition, we examined if prior academic functioning in kindergarten moderated the association between negative expressivity (level in kindergarten and change over time) and academic functioning in first grade. The slope of negative expressivity was negatively associated with first grade school engagement and passage comprehension for children who had lower kindergarten school engagement and passage comprehension, respectively, but was unrelated for those with higher academic functioning in kindergarten. That is, for children who had lower kindergarten school engagement and passage comprehension, greater declines in negative expressivity were associated with higher first grade school engagement and passage comprehension, respectively. The findings suggest that negative emotional expressivity in school is associated with academic outcomes in first grade and, in some cases, this association is more pronounced for children who had lower kindergarten academic functioning.

Sleep duration moderates the association between children's temperament and academic achievement

The primary goal of this study was to determine whether sleep duration moderated the relations of two dimensions of children's temperament, shyness and negative emotion, to academic achievement. In the autumn, parents and teachers reported on kindergarteners' and first graders' (N = 103) shyness and negative emotion and research assistants observed negative emotion in the classroom. In the spring, children wore actigraphs that measured their sleep for five consecutive school nights, and they completed the Woodcock Johnson-III standardized tests of achievement. Interactions between temperament and sleep duration predicting academic achievement were computed. Interactions of sleep duration with parent-reported shyness, teacher-reported negative emotion, and observed negative emotion indicated that the negative relations of shyness or negative emotion to academic achievement were strongest when children slept less. Results suggest that sleep duration may be an important bio-regulatory factor to consider in young children's early academic achievement.

Bidirectional associations between emotions and school adjustment

OBJECTIVE

We examined the relations of children's (N = 301) observed expression of negative and positive emotion in classes or nonclassroom school contexts (i.e., lunch and recess) to school adjustment from kindergarten to first grade.

METHOD

Naturalistic observations of children's emotional expressivity were collected, as were teachers' reports of children's school engagement and relationship quality with teachers and peers.

RESULTS

In longitudinal panel models, greater teacher-student conflict and lower student engagement in kindergarten predicted greater negative expressivity in both school contexts. School engagement and peer acceptance in kindergarten positively predicted first grade positive emotion in the classroom. Suggestive of possible bidirectional relations, there was also small unique prediction (near significant) from negative expressivity at lunch and recess to higher teacher-student conflict, from negative expressivity in the classroom to low peer acceptance, and from positive expressivity in the classroom to higher peer acceptance.

CONCLUSIONS

The pattern of findings suggests that the quality of experience at school uniquely predicts children's emotional expressivity at school more consistently than vice versa-a finding that highlights the important role of school context in young children's emotionality at school.

Effortful control and school adjustment: The moderating role of classroom chaos

Guided by the person by environment framework, the primary goal of this study was to determine whether classroom chaos moderated the relation between effortful control and kindergarteners' school adjustment. Classroom observers reported on children's (N = 301) effortful control in the fall. In the spring, teachers reported on classroom chaos and school adjustment outcomes (teacher-student relationship closeness and conflict, and school liking and avoidance). Cross-level interactions between effortful control and classroom chaos predicting school adjustment outcomes were assessed. A consistent pattern of interactions between effortful control and classroom chaos indicated that the relations between effortful control and the school adjustment outcomes were strongest in high chaos classrooms. Post-hoc analyses indicated that classroom chaos was associated with poor school adjustment when effortful control was low, suggesting that the combination of high chaos and low effortful control was associated with the poorest school outcomes.

Balance in Positive Emotional Expressivity Across School Contexts Relates to Kindergarteners' Adjustment

Positive emotional expressivity has been associated with increased social competence and decreased maladjustment in childhood. However, a few researchers have found null or even positive associations between positive emotional expressivity and maladjustment, which suggests that there may be nuanced associations of positive expressivity, perhaps as a function of the social context in which it is expressed. We examined whether observed positive emotional expressivity balance across peer-oriented/recreational and learning contexts predicted kindergarten children's adjustment (N = 301).

RESEARCH FINDINGS

Higher positive expressivity during lunch/recess compared to positive expressivity in the classroom was associated with lower teacher-student conflict, externalizing behaviors, and depressive symptoms. In addition, overall positive emotional expressivity predicted lower externalizing behaviors as well as lower depressive and anxiety symptoms.

PRACTICE OR POLICY

The results suggest the importance of assessing observed positive emotional expressivity in context as a potential indicator of children's maladjustment risk and the need for children to adapt their emotions to different contexts. Implications for assessing and supporting positive emotional expression balance and training emotional regulation in school are discussed.

Elementary Students' Effortful Control and Academic Achievement: The Mediating Role of Teacher-Student Relationship Quality

This study evaluated the association between effortful control in kindergarten and academic achievement one year later (N = 301), and whether teacher-student closeness and conflict in kindergarten mediated the association. Parents, teachers, and observers reported on children's effortful control, and teachers reported on their perceived levels of closeness and conflict with students. Students completed the passage comprehension and applied problems subtests of the Woodcock-Johnson tests of achievement, as well as a behavioral measure of effortful control. Analytical models predicting academic achievement were estimated using a structural equation model framework. Effortful control positively predicted academic achievement even when controlling for prior achievement and other covariates. Mediation hypotheses were tested in a separate model; effortful control positively predicted teacher-student closeness and strongly, negatively predicted teacher-student conflict. Teacher-student closeness and effortful control, but not teacher-student conflict, had small, positive associations with academic achievement. Effortful control also indirectly predicted higher academic achievement through its positive effect on teacher-student closeness and via its positive relation to early academic achievement. The findings suggest that teacher-student closeness is one mechanism by which effortful control is associated with academic achievement. Effortful control was also a consistent predictor of academic achievement, beyond prior achievement levels and controlling for teacher-student closeness and conflict, with implications for intervention programs on fostering regulation and achievement concurrently.

Observed Emotions as Predictors of Quality of Kindergartners' Social Relationships

This study evaluated whether positive and anger emotional frequency (the proportion of instances an emotion was observed) and intensity (the strength of an emotion when it was observed) uniquely predicted social relationships among kindergarteners (N = 301). Emotions were observed as naturally occurring at school in the fall term and multiple reporters (peers and teachers) provided information on quality of relationships with children in the spring term. In structural equation models, positive emotion frequency, but not positive emotion intensity, was positively related to peer acceptance and negatively related to peer rejection. In contrast, the frequency of anger provided unique positive prediction of teacher-student conflict and negative prediction of peer acceptance. Furthermore, anger intensity negatively predicted teacher-student closeness and positively predicted teacher-student conflict. Implications for promoting social relationships in school are discussed.

Concurrent and longitudinal associations of peers' acceptance with emotion and effortful control in kindergarten

The purpose of the study was to evaluate bidirectional associations between peer acceptance and both emotion and effortful control during kindergarten (N = 301). In both the fall and spring semesters, we obtained peer nominations of acceptance, measures of positive and negative emotion based on naturalistic observations in school (i.e., classroom, lunch/recess), and observers' reports of effortful control (i.e., inhibitory control, attention focusing) and emotions (i.e., positive, negative). In structural equation panel models, peer acceptance in fall predicted higher effortful control in spring. Effortful control in fall did not predict peer acceptance in spring. Negative emotion predicted lower peer acceptance across time for girls but not for boys. Peer acceptance did not predict negative or positive emotion over time. In addition, we tested interactions between positive or negative emotion and effortful control predicting peer acceptance. Positive emotion predicted higher peer acceptance for children low in effortful control.

Emotional expression in school context, social relationships, and academic adjustment in kindergarten

This study evaluated direct relations of both kindergarteners' (N = 301) naturalistically observed emotion in 2 different school contexts and early kindergarten verbal competence to academic adjustment (i.e., standardized measures of academic achievement, teacher-reported academic skills, teacher-reported and observed school engagement) and if these relations were mediated by teacher-reported conflict with students and by peer acceptance. When controlling for verbal competence, positive emotions expressed in the classroom context positively directly predicted academic skills, whereas positive emotions expressed outside class (lunch/recess) negatively predicted academic skills. Negative emotions observed in the classroom context and during lunch/recess negatively predicted academic achievement. Positive emotions observed in both contexts indirectly predicted higher school engagement through its positive relation to peer acceptance; positive emotions expressed in lunch and recess indirectly predicted higher school engagement via lower teacher-student conflict. Negative emotions observed in both contexts also indirectly predicted lower school engagement via higher teacher-student conflict. Furthermore, verbal competence indirectly predicted higher academic adjustment via lower teacher-student conflict. Moreover, verbal competence moderated the association between peer acceptance (but not teacher-student conflict) and academic adjustment. Because verbal competence moderated the associations from peer competence, positive emotions in both contexts indirectly predicted higher academic adjustment via higher peer acceptance primarily for children with low, but not high, initial verbal competence. (PsycINFO Database Record

Children's Sleep and Academic Achievement: The Moderating Role of Effortful Control

Poor sleep is thought to interfere with children's learning and academic achievement (AA). However, existing research and theory indicate there are factors that may mitigate the academic risk associated with poor sleep. The purpose of this study was to examine the moderating role of children's effortful control (EC) on the relation between sleep and AA in young children. One hundred and three 4.5- to 7-year-olds (M = 5.98 years, SD = 0.61) wore a wrist-based actigraph for five continuous weekday nights. Teachers and coders reported on children's EC. EC was also assessed with a computer-based task at school. Additionally, we obtained a standardized measure of children's AA. There was a positive main effect of sleep efficiency to AA. Several relations between sleep and AA were moderated by EC and examination of the simple slopes indicated that the negative relation between sleep and AA was only significant at low levels of EC.

Relations of Positive and Negative Expressivity and Effortful Control to Kindergarteners' Student-Teacher Relationship, Academic Engagement, and Externalizing Problems at School

The current study examined the role of naturally-occurring negative and positive emotion expressivity in kindergarten and children's effortful control (EC) on their relationships with teachers, academic engagement, and problems behaviors in school. Further, the potential moderating role of EC on these important school outcomes was assessed. Emotion and engagement were observed at school. EC was assessed by multiple methods. Teachers reported on their student-teacher relationships and student's externalizing behaviors. Children's emotion expressivity and EC were related to engagement and relationships with teachers as well as behavioral problems at school. Children low in EC may be particularly vulnerable to the poor outcomes associated with relatively intense emotion expressivity as they struggle to manage their emotions and behaviors in the classroom.

Observed emotion frequency versus intensity as predictors of socioemotional maladjustment

The purpose of this study was to assess whether observed emotional frequency (the proportion of instances an emotion was observed) and intensity (the strength of an emotion when it was observed) uniquely predicted kindergartners' (N = 301) internalizing and externalizing problems. Analyses were tested in a structural equation modeling (SEM) framework with data from multireporters (reports of problem behaviors from teachers and parents) and naturalistic observations of emotion in the fall semester. For observed positive emotion, both frequency and intensity negatively predicted parent- or teacher-reported internalizing symptoms. Anger frequency positively predicted parent- and teacher-reported externalizing symptoms, whereas anger intensity positively predicted parent- and teacher-reported externalizing and parent-reported internalizing symptoms. The findings support the importance of examining both aspects of emotion when predicting maladjustment.

A gaseous metal disk around a white dwarf

The destiny of planetary systems through the late evolution of their host stars is very uncertain. We report a metal-rich gas disk around a moderately hot and young white dwarf. A dynamical model of the double-peaked emission lines constrains the outer disk radius to just 1.2 solar radii. The likely origin of the disk is a tidally disrupted asteroid, which has been destabilized from its initial orbit at a distance of more than 1000 solar radii by the interaction with a relatively massive planetesimal object or a planet. The white dwarf mass of 0.77 solar mass implies that planetary systems may form around high-mass stars.

Use of praziquantel for the control ofMoniezia expansain lambs

The efficacy of a drench containing praziquantel in combination with levamisole was evaluated in four trials performed in the 1990-91 and 1992-93 seasons in the Waikato Region of New Zealand. The trials involved 93 naturally infected lambs and compared the efficacy of a 3.75 mg/kg praziquantel 7.5mg/kg levamisole drench against Moniezia expansa, with albendazole, an albendazole-levamisole combination and oxyclozanide-levamisole combination in controlled trials. There was no significant reduction in the number of Moniezia expansa scoleces or proglottids in the control, albendazole and albendazole-levamisole groups. Oxyclozanide gave a high clearance of proglottids, but a 28% reduction of scoleces. The praziquantel-levamisole combination demonstrated complete removal of segments in all trials, and of scoleces in two trials. One scolex was found in each of the two other trials. The combination was also tested for efficacy against nematode parasites. Total worm counts indicated that levamisole in the praziquantel-levamisole combination drench retained its efficacy. The economic benefits of the use of the praziquantel-levamisole drench were investigated. This trial compared the liveweight gains of three groups of 100 lambs treated twice 4 weeks apart with either levamisole or with the praziquantel-levamisole combination or acting as untreated control group. The group treated with the praziquantel-levamisole combination gained significantly more weight in both 4-week periods and overall, when compared with either the control or levamisole treated animals.

A hemodynamic comparison of Omniscience and Medtronic Hall aortic prostheses

BACKGROUND AND AIMS OF THE STUDY

Preliminary reports have suggested hemodynamic disparities between single leaflet tilting disc prostheses. We tested the hypothesis that similarities in prosthetic design may not necessarily indicate hemodynamic equivalence.

MATERIALS AND METHODS

In a retrospective analysis, we compared the functional characteristics of two single tilting disc (Omniscience and Medtronic Hall) prostheses implanted in the aortic position in 30 patients matched for valve size and left ventricular systolic function.

RESULTS

Echocardiographic and Doppler analysis blinded to patient and valve type indicated similar quantitative left ventricular ejection fractions (64% +/- 6% for both) and cardiac outputs (4.8 +/- 1.2 vs. 4.6 +/- 1.2 l/min, p = 0.65) in the Onmiscience and Medtronic Hall groups, respectively. Transprosthetic instantaneous peak gradients were greater for Omniscience than for Medtronic Hall valves (44 +/- 8 vs. 35 +/- 11 mmHg, p < or = 0.02), as were the mean values (24 +/- 6 vs. 18 +/- 6 mmHg, p = 0.01). Even when 21 and 23 mm prostheses were analyzed separately to allow for unequal sewing ring diameters in the smallest valve sizes (Omniscience = 19 mm, Medtronic Hall = 20 mm), higher gradients were noted in the Omniscience prostheses. Effective orifice areas were smaller in the Omniscience than Medtronic Hall prostheses whether data from all prostheses (0.92 +/- 0.11 cm2 vs. 1.09 +/- 0.18 cm2, p < or = 0.05), or only data from 21 and 23 mm valves (0.94 +/- 0.11 cm2 vs. 1.10 +/- 0.18 cm2, p < 0.05) were included. Similarly, the dimensionless obstructive index, a parameter independent of left ventricular flow and annular size, was reduced in the Omniscience valves, indicating greater obstruction, whether all valves (0.31 +/- 0.04 vs. 0.36 +/- 0.07, p < or = 0.01) or only 21 and 23 mm valves (0.31 +/- 0.04 vs. 0.36 +/- .04, p < 0.001) were analyzed.

CONCLUSION

Despite prosthetic design similarities, resting hemodynamic assessment indicates greater stenosis in Omniscience than Medtronic Hall valves when placed in the aortic position. The long term effects of these differences in terms of ventricular diastolic and systolic function and mass regression requires further evaluation.