Science.gov

Sample records for academic growth trajectories

  1. Academic Growth Trajectories and Family Relationships among African American Youth

    PubMed Central

    Dotterer, Aryn M.; Lowe, Katie; McHale, Susan M.

    2016-01-01

    This study explored trajectories of African American youths’ academic functioning and assessed whether changes in parent-adolescent relationships were associated with changes in youths’ academic functioning. The data were drawn from a three-year longitudinal study of gender socialization and development in two-parent African American families and included 197 families. Findings revealed gender differences in achievement trajectories and indicated that boys not only had lower levels of academic achievement compared to girls, but also experienced steeper declines in school self-esteem during adolescence. Changes in parent-adolescent relationship quality were linked to changes in academic functioning: Increases in conflict were related to decreases in GPA, school bonding, and school self-esteem and increases in warmth were related to increases in school bonding and school self-esteem. PMID:27122959

  2. Academic Trajectories of Newcomer Immigrant Youth

    ERIC Educational Resources Information Center

    Suarez-Orozco, Carola; Gaytan, Francisco X.; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

    2010-01-01

    Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve…

  3. Academic trajectories of newcomer immigrant youth.

    PubMed

    Suárez-Orozco, Carola; Gaytán, Francisco X; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

    2010-05-01

    Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve analysis revealed that although some newcomer students performed at high or improving levels over time, others showed diminishing performance. Multinomial logistic regressions identified significant group differences in academic trajectories, particularly between the high-achieving youth and the other groups. In keeping with ecological-developmental and stage-environment fit theories, School Characteristics (school segregation rate, school poverty rate, and student perceptions of school violence), Family Characteristics (maternal education, parental employment, and household structure), and Individual Characteristics (academic English proficiency, academic engagement, psychological symptoms, gender, and 2 age-related risk factors, number of school transitions and being overaged for grade placement) were associated with different trajectories of academic performance. A series of case studies triangulate many of the quantitative findings as well as illuminate patterns that were not detected in the quantitative data. Thus, the mixed-methods approach sheds light on the cumulative developmental challenges that immigrant students face as they adjust to their new educational settings.

  4. Growth Trajectories of Task Value and Self-Efficacy across an Academic Semester

    ERIC Educational Resources Information Center

    Johnson, Marcus Lee; Edwards, Ordene V.; Dai, Ting

    2014-01-01

    Many scholars have argued that motivation is dynamic and malleable across time and contexts. In this article, we investigated changes in undergraduates' task value and self-efficacy across an academic semester. Sixty three undergraduate students completed the Motivated Strategies for Learning Questionnaire across five time points in their…

  5. Growth Trajectories of Mathematics Achievement: Longitudinal Tracking of Student Academic Progress

    ERIC Educational Resources Information Center

    Mok, Magdalena M. C.; McInerney, Dennis M.; Zhu, Jinxin; Or, Anthony

    2015-01-01

    Background: A number of methods to investigate growth have been reported in the literature, including hierarchical linear modelling (HLM), latent growth modelling (LGM), and multidimensional scaling applied to longitudinal profile analysis (LPAMS). Aims: This study aimed at modelling the mathematics growth of students over a span of 6 years from…

  6. Contributions to Variations in Academic Trajectories amongst Recent Immigrant Youth

    ERIC Educational Resources Information Center

    Suarez-Orozco, Carola; Bang, Hee Jin; Onaga, Marie

    2010-01-01

    Immigration presents both challenges and opportunities that affect students' academic achievement. Over the course of five years, varying academic trajectories were identified for recent immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve analysis revealed that although some students…

  7. Mothers' Depression and Educational Attainment and Their Children's Academic Trajectories

    ERIC Educational Resources Information Center

    Augustine, Jennifer March; Crosnoe, Robert

    2010-01-01

    In this study, we take a dynamic approach to studying the connections among mothers' education, their depression, and their children's academic trajectories during elementary school. Applying latent growth curve modeling to longitudinal data from the National Institute of Child Health and Human Development's Study of Early Child Care and Youth…

  8. Academic Achievement Trajectories of Adolescents from Mexican and East Asian Immigrant Families in the United States

    ERIC Educational Resources Information Center

    Jeong, Yu-Jin; Acock, Alan C.

    2014-01-01

    Drawing on the National Educational Longitudinal Survey 1988 (NELS:88), this study identified (1) the growth pattern of academic achievement of adolescent children from Mexican and East Asian immigrant families; (2) investigated to what extent ethnicity and family capital influenced the trajectories in the academic achievement of children from…

  9. Gene–Environment Interactions on Growth Trajectories

    PubMed Central

    Wang, Shuang; Xiong, Wei; Ma, Weiping; Chanock, Stephen; Jedrychowski, Wieslaw; Wu, Rongling; Perera, Frederica P.

    2012-01-01

    It has been suggested that children with larger brains tend to perform better on IQ tests or cognitive function tests. Prenatal head growth and head growth in infancy are two crucial periods for subsequent intelligence. Studies have shown that environmental exposure to air pollutants during pregnancy is associated with fetal growth reduction, developmental delay, and reduced IQ. Meanwhile, genetic polymorphisms may modify the effect of environment on head growth. However, studies on gene–environment or gene–gene interactions on growth trajectories have been quite limited partly due to the difficulty to quantitatively measure interactions on growth trajectories. Moreover, it is known that assessing the significance of gene–environment or gene–gene interactions on cross-sectional outcomes empirically using the permutation procedures may bring substantial errors in the tests. We proposed a score that quantitatively measures interactions on growth trajectories and developed an algorithm with a parametric bootstrap procedure to empirically assess the significance of the interactions on growth trajectories under the likelihood framework. We also derived a Wald statistic to test for interactions on growth trajectories and compared it to the proposed parametric bootstrap procedure. Through extensive simulation studies, we demonstrated the feasibility and power of the proposed testing procedures. We applied our method to a real dataset with head circumference measures from birth to age 7 on a cohort currently being conducted by the Columbia Center for Children's Environmental Health (CCCEH) in Krakow, Poland, and identified several significant gene–environment interactions on head circumference growth trajectories. PMID:22311237

  10. The Application of Various Nonlinear Models to Describe Academic Growth Trajectories: An Empirical Analysis Using Four-Wave Longitudinal Achievement Data from a Large Urban School District

    ERIC Educational Resources Information Center

    Shin, Tacksoo

    2012-01-01

    This study introduced various nonlinear growth models, including the quadratic conventional polynomial model, the fractional polynomial model, the Sigmoid model, the growth model with negative exponential functions, the multidimensional scaling technique, and the unstructured growth curve model. It investigated which growth models effectively…

  11. Linear growth trajectories in Zimbabwean infants12

    PubMed Central

    Gough, Ethan K; Moodie, Erica EM; Prendergast, Andrew J; Ntozini, Robert; Moulton, Lawrence H; Humphrey, Jean H; Manges, Amee R

    2016-01-01

    Background: Undernutrition in early life underlies 45% of child deaths globally. Stunting malnutrition (suboptimal linear growth) also has long-term negative effects on childhood development. Linear growth deficits accrue in the first 1000 d of life. Understanding the patterns and timing of linear growth faltering or recovery during this period is critical to inform interventions to improve infant nutritional status. Objective: We aimed to identify the pattern and determinants of linear growth trajectories from birth through 24 mo of age in a cohort of Zimbabwean infants. Design: We performed a secondary analysis of longitudinal data from a subset of 3338 HIV-unexposed infants in the Zimbabwe Vitamin A for Mothers and Babies trial. We used k-means clustering for longitudinal data to identify linear growth trajectories and multinomial logistic regression to identify covariates that were associated with each trajectory group. Results: For the entire population, the mean length-for-age z score declined from −0.6 to −1.4 between birth and 24 mo of age. Within the population, 4 growth patterns were identified that were each characterized by worsening linear growth restriction but varied in the timing and severity of growth declines. In our multivariable model, 1-U increments in maternal height and education and infant birth weight and length were associated with greater relative odds of membership in the least–growth restricted groups (A and B) and reduced odds of membership in the more–growth restricted groups (C and D). Male infant sex was associated with reduced odds of membership in groups A and B but with increased odds of membership in groups C and D. Conclusion: In this population, all children were experiencing growth restriction but differences in magnitude were influenced by maternal height and education and infant sex, birth weight, and birth length, which suggest that key determinants of linear growth may already be established by the time of birth

  12. Academic Growth Trajectories of ELLs in NAEP Data: The Case of Fourth- and Eighth-Grade ELLs and Non-ELLs on Mathematics and Reading Tests

    ERIC Educational Resources Information Center

    Polat, Nihat; Zarecky-Hodge, Ashley; Schreiber, James B.

    2016-01-01

    Utilizing the National Assessment of Educational Progress (NAEP) data, this study examined (1) how fourth and eighth-grade ELLs' mathematics and reading scores on national tests compared to their non-ELL peers' scores over the testing period between 2003 and 2011, and (2) if gender and ethnicity contributed to variation in the growth patterns…

  13. The academic trajectories of children of immigrants and their school environments.

    PubMed

    Han, Wen-Jui

    2008-11-01

    Data from approximately 14,000 children in the Early Childhood Longitudinal Survey--Kindergarten Cohort were analyzed to examine the associations between children's immigrant status and their academic trajectories from kindergarten to 3rd grade, with particular attention to the effects of school environments. Growth curve modeling results indicated that most children of Latin American origin improved their reading and math scores faster than non-Hispanic White children, thus narrowing their initial score gap and sometimes even surpassing White children by 3rd grade. In contrast, although they maintained higher reading and math scores, children from East Asia and India showed decreasing scores over time, which tended to narrow their initial score advantage over non-Hispanic White children. School-level factors accounted partially for these differences. Particularly in terms of the academic trajectories, children of Latin American origin responded more to school-level factors than did children of Asian origin, who responded more to child and family background, with the exception of children from Vietnam, Thailand, Cambodia, and Laos, who responded more to school-level factors. Simulation results point to the importance of school resources for the academic trajectories of children of immigrants.

  14. Academic Provenance: Mapping Geoscience Students' Academic Pathways to their Career Trajectories

    NASA Astrophysics Data System (ADS)

    Houlton, H. R.; Gonzales, L. M.; Keane, C. M.

    2011-12-01

    Targeted recruitment and retention efforts for the geosciences have become increasingly important with the growing concerns about program visibility on campuses, and given that geoscience degree production remains low relative to the demand for new geoscience graduates. Furthermore, understanding the career trajectories of geoscience degree recipients is essential for proper occupational placement. A theoretical framework was developed by Houlton (2010) to focus recruitment and retention efforts. This "pathway model" explicitly maps undergraduate students' geoscience career trajectories, which can be used to refine existing methods for recruiting students into particular occupations. Houlton's (2010) framework identified three main student population groups: Natives, Immigrants or Refugees. Each student followed a unique pathway, which consisted of six pathway steps. Each pathway step was comprised of critical incidents that influenced students' overall career trajectories. An aggregate analysis of students' pathways (Academic Provenance Analysis) showed that different populations' pathways exhibited a deviation in career direction: Natives indicated intentions to pursue industry or government sectors, while Immigrants intended to pursue academic or research-based careers. We expanded on Houlton's (2010) research by conducting a follow-up study to determine if the original participants followed the career trajectories they initially indicated in the 2010 study. A voluntary, 5-question, short-answer survey was administered via email. We investigated students' current pathway steps, pathway deviations, students' goals for the near future and their ultimate career ambitions. This information may help refine Houlton's (2010) "pathway model" and may aid geoscience employers in recruiting the new generation of professionals for their respective sectors.

  15. Optimal growth trajectories with finite carrying capacity.

    PubMed

    Caravelli, F; Sindoni, L; Caccioli, F; Ududec, C

    2016-08-01

    We consider the problem of finding optimal strategies that maximize the average growth rate of multiplicative stochastic processes. For a geometric Brownian motion, the problem is solved through the so-called Kelly criterion, according to which the optimal growth rate is achieved by investing a constant given fraction of resources at any step of the dynamics. We generalize these finding to the case of dynamical equations with finite carrying capacity, which can find applications in biology, mathematical ecology, and finance. We formulate the problem in terms of a stochastic process with multiplicative noise and a nonlinear drift term that is determined by the specific functional form of carrying capacity. We solve the stochastic equation for two classes of carrying capacity functions (power laws and logarithmic), and in both cases we compute the optimal trajectories of the control parameter. We further test the validity of our analytical results using numerical simulations.

  16. Optimal growth trajectories with finite carrying capacity

    NASA Astrophysics Data System (ADS)

    Caravelli, F.; Sindoni, L.; Caccioli, F.; Ududec, C.

    2016-08-01

    We consider the problem of finding optimal strategies that maximize the average growth rate of multiplicative stochastic processes. For a geometric Brownian motion, the problem is solved through the so-called Kelly criterion, according to which the optimal growth rate is achieved by investing a constant given fraction of resources at any step of the dynamics. We generalize these finding to the case of dynamical equations with finite carrying capacity, which can find applications in biology, mathematical ecology, and finance. We formulate the problem in terms of a stochastic process with multiplicative noise and a nonlinear drift term that is determined by the specific functional form of carrying capacity. We solve the stochastic equation for two classes of carrying capacity functions (power laws and logarithmic), and in both cases we compute the optimal trajectories of the control parameter. We further test the validity of our analytical results using numerical simulations.

  17. Parent-Child Acculturation Profiles as Predictors of Chinese American Adolescents’ Academic Trajectories

    PubMed Central

    Kim, Su Yeong; Wang, Yijie; Chen, Qi; Shen, Yishan; Hou, Yang

    2014-01-01

    Acculturation plays a critical role in the adjustment of Asian Americans, as a large proportion of them are immigrants in the U.S. However, little is known about how acculturation influences Asian American adolescents’ academic trajectories over time. Using a longitudinal sample of 444 Chinese American families (54% female children), the current study explored the effect of mothers’, fathers’, and adolescents’ individual acculturation profiles and parent-child acculturation dissonance on adolescents’ academic trajectories from 8th to 12th grade. Academic performance was measured by Grade Point Average (GPA), and by standardized test scores in English Language Arts (ELA) and Math every year. Latent growth modeling analyses showed that adolescents with a Chinese-oriented father showed faster decline in GPA, and Chinese-oriented adolescents had lower initial ELA scores. Adolescents whose parents had American-oriented acculturation profiles tended to have lower initial Math scores. These results suggest that Chinese and American profiles may be disadvantageous for certain aspects of academic performance, and bicultural adolescents and/or adolescents with bicultural parents are best positioned to achieve across multiple domains. In terms of the role of parent-child acculturation dissonance on academic trajectories, the current study highlighted the importance of distinguishing among different types of dissonance. Adolescents who were more Chinese-oriented than their parents tended to have the lowest initial ELA scores, and adolescents experiencing more normative acculturation dissonance (i.e., who were more American-oriented than their parents) had the highest initial ELA scores. No effects of parent-child acculturation dissonance were observed for GPAs or standardized Math scores. Altogether, the current findings add nuances to the current understanding of acculturation and adolescent adjustment. PMID:24820295

  18. Parent-child acculturation profiles as predictors of Chinese American adolescents' academic trajectories.

    PubMed

    Kim, Su Yeong; Wang, Yijie; Chen, Qi; Shen, Yishan; Hou, Yang

    2015-06-01

    Acculturation plays a critical role in the adjustment of Asian Americans, as a large proportion of them are immigrants in the US. However, little is known about how acculturation influences Asian American adolescents' academic trajectories over time. Using a longitudinal sample of 444 Chinese American families (54% female children), the current study explored the effect of mothers', fathers', and adolescents' individual acculturation profiles and parent-child acculturation dissonance on adolescents' academic trajectories from 8th to 12th grade. Academic performance was measured by grade point average (GPA), and by standardized test scores in English language arts (ELA) and Math every year. Latent growth modeling analyses showed that adolescents with a Chinese-oriented father showed faster decline in GPA, and Chinese-oriented adolescents had lower initial ELA scores. Adolescents whose parents had American-oriented acculturation profiles tended to have lower initial Math scores. These results suggest that Chinese and American profiles may be disadvantageous for certain aspects of academic performance, and bicultural adolescents and/or adolescents with bicultural parents are best positioned to achieve across multiple domains. In terms of the role of parent-child acculturation dissonance on academic trajectories, the current study highlighted the importance of distinguishing among different types of dissonance. Adolescents who were more Chinese-oriented than their parents tended to have the lowest initial ELA scores, and adolescents experiencing more normative acculturation dissonance (i.e., who were more American-oriented than their parents) had the highest initial ELA scores. No effects of parent-child acculturation dissonance were observed for GPAs or standardized Math scores. Altogether, the current findings add nuances to the current understanding of acculturation and adolescent adjustment.

  19. Genetic and environmental influences on academic achievement trajectories during adolescence.

    PubMed

    Johnson, Wendy; McGue, Matt; Iacono, William G

    2006-05-01

    Most studies have considered the effects of particular characteristics on academic achievement individually, which means that little is known about how they function together. Using the population-based Minnesota Twin Family Study, the authors investigated the effects of child academic engagement (interest, involvement, effort), IQ, depression, externalizing behavior, and family environmental risk on academic achievement (reported school grades) from ages 11 through 17. Hierarchical linear growth curve modeling showed main effects on initial reported Grades for all variables, and IQ mitigated the deleterious effects of family risk and externalizing. Only engagement affected change in Grades through adolescence. Influences on initial Grades were strongly genetically influenced, associated primarily with IQ, engagement, and externalizing behavior. Shared environmental influences on initial Grades linked engagement, IQ, and family risk. Genetic influences on change in Grades were substantial, but they were not associated with the academic, family risk, and mental health covarying factors. These results indicate that age 11 achievement and change in achievement through adolescence show systematic patterns and document the existence of individual differences in the commonly shared developmental experience of adapting to the school environment.

  20. Academic Outcome Trajectories of Students with ADHD: Does Exceptional Education Status Matter?

    ERIC Educational Resources Information Center

    Bussing, Regina; Porter, Phillip; Zima, Bonnie T.; Mason, Dana; Garvan, Cynthia; Reid, Robert

    2012-01-01

    Attention-deficit/hyperactivity disorder (ADHD) has been associated with poor academic performance, but little is known about learning trajectories and risk factors for poor academic outcomes. This study investigates the relationship between ADHD and academic performance in students with ADHD (n = 87), students with subclinical ADHD (n = 23), and…

  1. Differential Growth Trajectories for Achievement Among Children Retained in First Grade: A Growth Mixture Model

    PubMed Central

    Chen, Qi; Hughes, Jan N.; Kwok, Oi-Man

    2013-01-01

    The authors investigated the differential effect of retention on the development of academic achievement from grade one to five on children retained in first grade over six years. Growth Mixture Model (GMM) analyses supported the existence of two distinct trajectory groups of retained children for both reading and math among 125 ethnically and linguistically diverse retained children. For each achievement domain, a low intercept/higher growth group (Class 1) and a high intercept/slower growth group (Class 2) were identified. Furthermore, Class 1 children were found to score lower on several measures of learning related skills (LRS) variables and were characterized by having poorer self-regulation and less prosocial behaviors, compared to the other group. Findings suggest that some children appear to benefit more from retention, in terms of higher reading and math growth, than others. Study findings have implications for selecting children into retention intervention and early intervention. PMID:24771882

  2. Developmental Trajectories of Academic Achievement in Chinese Children: Contributions of Early Social-Behavioral Functioning

    ERIC Educational Resources Information Center

    Fu, Rui; Chen, Xinyin; Wang, Li; Yang, Fan

    2016-01-01

    This study explored the developmental trajectories of academic achievement and the contributions of early social behaviors and problems to these trajectories in Chinese children. Data were collected each year in 5 consecutive years from a sample of elementary schoolchildren in China (initially N = 1,146, 609 boys, initial M [subscript age] = 8.33…

  3. Developmental Trajectories of Adolescent Popularity: A Growth Curve Modelling Analysis

    ERIC Educational Resources Information Center

    Cillessen, Antonius H. N.; Borch, Casey

    2006-01-01

    Growth curve modelling was used to examine developmental trajectories of sociometric and perceived popularity across eight years in adolescence, and the effects of gender, overt aggression, and relational aggression on these trajectories. Participants were 303 initially popular students (167 girls, 136 boys) for whom sociometric data were…

  4. Growth Trajectories of Health Behaviors from Adolescence through Young Adulthood

    PubMed Central

    Wiium, Nora; Breivik, Kyrre; Wold, Bente

    2015-01-01

    Based on nine waves of data collected during a period of 17 years (1990–2007), the present study explored different developmental trajectories of the following unhealthy behaviors: regular smoking, lack of regular exercise, lack of daily fruit intake, and drunkenness. A baseline sample of 1195 13-year-old pupils was from 22 randomly selected schools in the Hordaland County in western Norway. Latent class growth analysis revealed three developmental trajectories. The first trajectory was a conventional trajectory, comprising 36.3% of participants, who showed changes in smoking, physical exercise, fruit intake, and drunkenness consistent with the prevailing age specific norms of these behaviors in the Norwegian society at the time. The second trajectory was a passive trajectory, comprising 25.5% of participants, who reported low levels of both healthy and unhealthy behaviors during the 17-year period. The third trajectory was an unhealthy trajectory, comprising 38.2% of participants, who had high levels of unhealthy behaviors over time. Several covariates were examined, but only sex and mother’s and father’s educational levels were found to be significantly associated with the identified trajectories. While these findings need to be replicated in future studies, the identification of the different trajectories suggests the need to tailor intervention according to specific needs. PMID:26516889

  5. Tutorship and Academic Trajectories in School: Comparative Study in Two Public Universities in Mexico

    ERIC Educational Resources Information Center

    Rodríguez, Emma Leticia Canales; Robelo, Octaviano García

    2015-01-01

    This work reports on the results of research on modalities of mentoring in the area of social sciences at two Mexican universities and their relationship with the academic trajectories of their students. The analysis focuses on the need to identify influences of different mentoring forms on students' academic performance. The theoretical…

  6. Trajectories of Chinese Students' Sense of School Belonging and Academic Achievement over the High School Transition Period

    ERIC Educational Resources Information Center

    Liu, Yangyang; Lu, Zuhong

    2011-01-01

    The present study identified the different patterns of Chinese students' academic achievement trajectories over the high school transition period and examined the relationships between students' sense of school belonging trajectories and the different patterns of academic achievement trajectories. In a sample of 567 Chinese high school students, a…

  7. Childhood trajectories of inattention-hyperactivity and academic achievement at 12 years.

    PubMed

    Salla, Julie; Michel, Grégory; Pingault, Jean Baptiste; Lacourse, Eric; Paquin, Stéphane; Galéra, Cédric; Falissard, Bruno; Boivin, Michel; Tremblay, Richard E; Côté, Sylvana M

    2016-11-01

    Few prospective studies spanning early childhood to early adolescence have examined separately the contribution of inattention and hyperactivity to academic achievement. The aim of the present study was to investigate whether the developmental trajectories of inattention and hyperactivity symptoms during early and middle childhood are independently associated with academic achievement at age 12 years. The independent associations between inattention and hyperactivity trajectories during early and middle childhood and academic performance at age 12 years were examined in a population-based longitudinal birth cohort (n = 2120). In adjusted analyses, high early childhood inattention trajectories were associated with teacher-rated academic performance in reading, writing and mathematics and with government exam score in writing. High and moderate inattention trajectories during middle childhood predicted lower performance on both teacher-rated academic performance and government exam scores in reading, writing, and mathematics. Hyperactivity was not a consistent predictor of educational outcomes. Childhood inattention symptoms rather than hyperactivity carry risk of poor educational outcomes at age 12 years. Children with high levels of inattention can be identified during the preschool years. Prevention programs supporting the development of attentional capacities and executive functions could help reduce the negative consequences of inattention.

  8. Trajectories of posttraumatic growth and depreciation after two major earthquakes.

    PubMed

    Marshall, Emma M; Frazier, Patricia; Frankfurt, Sheila; Kuijer, Roeline G

    2015-03-01

    This study examined trajectories of posttraumatic growth or depreciation (i.e., positive or negative life change) in personal strength and relationships after 2 major earthquakes in Canterbury, New Zealand using group-based trajectory modeling. Participants completed questionnaires regarding posttraumatic growth or depreciation in personal strength and relationship domains 1 month after the first earthquake in September 2010 (N = 185) and 3 months (n = 156) and 12 months (n = 144) after the more severe February 2011 earthquake. Three classes of growth or depreciation patterns were found for both domains. For personal strength, most of the participants were grouped into a "no growth or depreciation" class and smaller proportions were grouped into either a "posttraumatic depreciation" or "posttraumatic growth" class. The 3 classes for relationships all reported posttraumatic growth, differing only in degree. None of the slopes were significant for any of the classes, indicating that levels of growth or depreciation reported after the first earthquake remained stable when assessed at 2 time points after the second earthquake. Multinomial logistic regression analyses examining pre- and postearthquake predictors of trajectory class membership revealed that those in the "posttraumatic growth" personal strength class were significantly younger and had significantly higher pre-earthquake mental health than those in the "posttraumatic depreciation" class. Sex was the only predictor of the relationship classes: No men were assigned to the "high posttraumatic growth" class. Implications and future directions are discussed.

  9. Identity-Trajectory: Reframing Early Career Academic Experience

    ERIC Educational Resources Information Center

    McAlpine, Lynn; Amundsen, Cheryl; Turner, Gill

    2014-01-01

    Our longitudinal qualitative research program examining doctoral student, post-PhD researcher and new lecturer experience is situated in an international literature documenting how early career academics learn through experience. In common with others, our work is framed within an identity perspective. What makes our view of identity distinct is a…

  10. Classifying Academically At-Risk First Graders into Engagement Types: Association with Long-Term Achievement Trajectories.

    PubMed

    Luo, Wen; Hughes, Jan N; Liew, Jeffrey; Kwok, Oiman

    2009-03-01

    Based on a sample of 480 academically at-risk first graders, we used a cluster analysis involving multimethod assessment (i.e., teacher-report, peer-evaluation, and self-report) of behavioral and psychological engagement to identify subtypes of academic engagement. Four theoretically and practically meaningful clusters were identified and labeled as cooperative (n = 95), resistive (n =96), enthusiastic (n = 188), and disaffected (n = 101). The four types did not differ in IQ measured with the Universal Nonverbal Intelligence Test. The cooperative group consisted of more female and Hispanic students, whereas the resistive group consisted of more male and African American students. The cooperative group was the most popular among peers, followed by the enthusiastic group. The disaffected and resistive groups had more emotional symptoms than the cooperative and enthusiastic groups. Academic engagement types also differed in growth trajectories of academic achievement measured with Woodcock Johnson III Tests of Achievement from second to fourth grade. For reading, the cooperative and enthusiastic groups outperformed the resistive and disaffected groups at the beginning. However, the growth rate was similar across engagement types. For math, the engagement types did not differ at the beginning. However, the cooperative group developed at a faster rate and had higher math achievement by fourth grade than the other types. The findings support the importance of teaching temperament-based regulatory skills and of providing a positive psychological climate for children's academic learning.

  11. An Exponential Growth Learning Trajectory: Students' Emerging Understanding of Exponential Growth through Covariation

    ERIC Educational Resources Information Center

    Ellis, Amy B.; Ozgur, Zekiye; Kulow, Torrey; Dogan, Muhammed F.; Amidon, Joel

    2016-01-01

    This article presents an Exponential Growth Learning Trajectory (EGLT), a trajectory identifying and characterizing middle grade students' initial and developing understanding of exponential growth as a result of an instructional emphasis on covariation. The EGLT explicates students' thinking and learning over time in relation to a set of tasks…

  12. Approaches to Academic Growth Assessment

    ERIC Educational Resources Information Center

    Anderman, Eric M.; Gimbert, Belinda; O'Connell, Ann A.; Riegel, Lisa

    2015-01-01

    Background: There is much interest in assessing growth in student learning. Assessments of growth have important implications and affect many policy decisions at many levels. Aims: In the present article, we review some of the different approaches to measuring growth and examine the implications of their usage. Sample: Samples used in research on…

  13. Interrupted Trajectories: The Impact of Academic Failure on the Social Mobility of Working-Class Students

    ERIC Educational Resources Information Center

    Byrom, Tina; Lightfoot, Nic

    2013-01-01

    Higher education (HE) is often viewed as a conduit for social mobility through which working-class students can secure improved life-chances. However, the link between HE and social mobility is largely viewed as unproblematic. Little research has explored the possible impact of academic failure (in HE) on the trajectories of working-class students…

  14. Trajectories of Discrimination across Adolescence: Associations with Academic, Psychological, and Behavioral Outcomes

    ERIC Educational Resources Information Center

    Hughes, Diane; Del Toro, Juan; Harding, Jessica F.; Way, Niobe; Rarick, Jason R. D.

    2016-01-01

    The authors explored trajectories of perceived discrimination over a 6-year period (five assessments in 6th-11th grade) in relation to academic, behavioral, and psychological adjustment in 8th and 11th grades. They distinguished discrimination from adults versus peers in addition to overt versus covert discrimination from peers. The sample…

  15. Academic and Career Trajectories of African American Males in San Bernardino

    ERIC Educational Resources Information Center

    Lyles, Lolita Laree

    2013-01-01

    A qualitative grounded theory approach is utilized to study the academic and career trajectories of twenty African American male collegiate students living in San Bernardino, California. There is limited research that explores the positive educational experiences of young adult African American males. Therefore, the aim of the present study is to…

  16. School Engagement Trajectories of Immigrant Youth: Risks and Longitudinal Interplay with Academic Success

    ERIC Educational Resources Information Center

    Motti-Stefanidi, Frosso; Masten, Ann; Asendorpf, Jens B.

    2015-01-01

    We examined behavioral school engagement trajectories of immigrant and non-immigrant early adolescents in relation to their academic achievement. Data were based on teacher judgments and school records. Students from immigrant families living in Greece and their non-immigrant classmates (N = 1057) were assessed over the three years of middle…

  17. Exploring Growth Trajectories of Problem Behavior in Young Children

    ERIC Educational Resources Information Center

    McCaffrey, Bethany L.

    2012-01-01

    Given the negative outcomes associated with problem behavior and the heightened risk for children with disabilities to display problematic behavior, the current study implemented hierarchical linear modeling to explore the growth trajectories of problem behavior in a nationally representative sample of preschool children with disabilities. Results…

  18. A developmental perspective on full- versus part-day kindergarten and children's academic trajectories through fifth grade.

    PubMed

    Votruba-Drzal, Elizabeth; Li-Grining, Christine P; Maldonado-Carreño, Carolina

    2008-01-01

    Children's kindergarten experiences are increasingly taking place in full- versus part-day programs, yet important questions remain about whether there are significant and meaningful benefits to full-day kindergarten. Using the Early Childhood Longitudinal Study's Kindergarten Cohort (N= 13,776), this study takes a developmental approach to examining associations between kindergarten program type and academic trajectories from kindergarten (ages 4-6 years) through 5th grade (ages 9-12 years). Full-day kindergarten was associated with greater growth of reading and math skills from fall until spring of kindergarten. Initial academic benefits diminished soon after kindergarten. The fade-out of the full-day advantage is in part explained by differences in the children who attend part- and full-day kindergarten as well as school characteristics.

  19. Developmental trajectories of adolescent popularity: a growth curve modelling analysis.

    PubMed

    Cillessen, Antonius H N; Borch, Casey

    2006-12-01

    Growth curve modelling was used to examine developmental trajectories of sociometric and perceived popularity across eight years in adolescence, and the effects of gender, overt aggression, and relational aggression on these trajectories. Participants were 303 initially popular students (167 girls, 136 boys) for whom sociometric data were available in Grades 5-12. The popularity and aggression constructs were stable but non-overlapping developmental dimensions. Growth curve models were run with SAS MIXED in the framework of the multilevel model for change [Singer, J. D., & Willett, J. B. (2003). Applied longitudinal data analysis. Oxford, UK: Oxford University Press]. Sociometric popularity showed a linear change trajectory; perceived popularity showed nonlinear change. Overt aggression predicted low sociometric popularity but an increase in perceived popularity in the second half of the study. Relational aggression predicted a decrease in sociometric popularity, especially for girls, and continued high-perceived popularity for both genders. The effect of relational aggression on perceived popularity was the strongest around the transition from middle to high school. The importance of growth curve models for understanding adolescent social development was discussed, as well as specific issues and challenges of growth curve analyses with sociometric data.

  20. Detecting Appropriate Trajectories of Growth in Latent Growth Models: The Performance of Information-Based Criteria

    ERIC Educational Resources Information Center

    Whittaker, Tiffany A.; Khojasteh, Jam

    2017-01-01

    Latent growth modeling (LGM) is a popular and flexible technique that may be used when data are collected across several different measurement occasions. Modeling the appropriate growth trajectory has important implications with respect to the accurate interpretation of parameter estimates of interest in a latent growth model that may impact…

  1. Academic and Social Functioning Associated with Attention-Deficit/Hyperactivity Disorder: Latent Class Analyses of Trajectories from Kindergarten to Fifth Grade.

    PubMed

    DuPaul, George J; Morgan, Paul L; Farkas, George; Hillemeier, Marianne M; Maczuga, Steve

    2016-10-01

    Children with attention-deficit/hyperactivity disorder (ADHD) are known to exhibit significantly lower academic and social functioning than other children. Yet the field currently lacks knowledge about specific impairment trajectories experienced by children with ADHD, which may constrain early screening and intervention effectiveness. Data were analyzed from a nationally representative U.S. cohort in the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K) for 590 children (72.7 % male) whose parents reported a formal diagnosis of ADHD. Children's math, reading, and interpersonal skills were assessed at 5 time points between kindergarten and fifth grade. Growth mixture model analyses indicated 4 latent trajectory classes for reading, 8 classes for math, and 4 classes for interpersonal skills. Membership in reading and math trajectory classes was strongly related; overlaps with interpersonal skills classes were weaker. Trajectory class membership was correlated with demographic characteristics and behavioral functioning. Children with ADHD display substantial heterogeneity in their reading, math, and interpersonal growth trajectories, with some groups of children especially likely to display relatively severe levels of academic and social impairment over time. Early screening and intervention to address impairment, particularly reading difficulties, among kindergarten students with ADHD is warranted.

  2. Kindergarten children's growth trajectories in reading and mathematics: who falls increasingly behind?

    PubMed

    Morgan, Paul L; Farkas, George; Wu, Qiong

    2011-01-01

    The authors used a large sample of children (N ≈ 7,400) participating in the Early Childhood Longitudinal Study--Kindergarten Cohort (ECLS-K) to estimate kindergarten children's academic achievement growth trajectories in reading and mathematics. The authors were particularly interested in whether the growth trajectories of children with learning disabilities (LD) or speech language impairments (SLI)--as well as those of other groups of children--were consistent with a cumulative or compensatory developmental cycle. Both LD and SLI children displayed significantly lower levels of kindergarten reading achievement than nondisabled children. However, and over the subsequent 5 years of elementary school, only children with SLI lagged increasingly behind nondisabled peers in their reading skills growth. The authors observed a different pattern for mathematics achievement. Children with LD, but not SLI, lagged increasingly behind nondisabled children in their mathematics skills growth. The authors also observed some consistency in "poor-get-poorer" effects across reading and mathematic achievement for additional population subgroups. Those kindergarten children who were from lower socioeconomic status families, who were African American, and who more frequently displayed learning-related behavior problems initially had lower levels of reading and mathematics achievement and also lagged increasingly behind in their acquisition of these skills over time. Some groups of children, including those with SLI, experience a cumulative rather than a compensatory cycle of achievement growth.

  3. Dynamic trajectories of growth and nitrogen capture by competing plants.

    PubMed

    Trinder, Clare; Brooker, Rob; Davidson, Hazel; Robinson, David

    2012-03-01

    Although dynamic, plant competition is usually estimated as biomass differences at a single, arbitrary time; resource capture is rarely measured. This restricted approach perpetuates uncertainty. To address this problem, we characterized the competitive dynamics of Dactylis glomerata and Plantago lanceolata as continuous trajectories of biomass production and nitrogen (N) capture. Plants were grown together or in isolation. Biomass and N content were measured at 17 harvests up to 76 d after sowing. Data were fitted to logistic models to derive instantaneous growth and N capture rates. Plantago lanceolata was initially more competitive in terms of cumulative growth and N capture, but D. glomerata was eventually superior. Neighbours reduced maximum biomass, but influenced both maximum N capture and its rate constant. Timings of maximal instantaneous growth and N capture rates were similar between species when they were isolated, but separated by 16 d when they were competing, corresponding to a temporal convergence in maximum growth and N capture rates in each species. Plants processed N and produced biomass differently when they competed. Biomass and N capture trajectories demonstrated that competitive outcomes depend crucially on when and how 'competition' is measured. This potentially compromises the interpretation of conventional competition experiments.

  4. Childhood body mass index growth trajectories and endometrial cancer risk

    PubMed Central

    Aarestrup, Julie; Gamborg, Michael; Tilling, Kate; Ulrich, Lian G.; Sørensen, Thorkild I.A.

    2016-01-01

    Previously, we found that excess weight already in childhood has positive associations with endometrial cancer; however, associations with changes in body mass index (BMI) during childhood are not well understood. Therefore, we examined whether growth in childhood BMI is associated with endometrial cancer and its sub‐types. A cohort of 155,505 girls from the Copenhagen School Health Records Register with measured weights and heights at the ages of 6–14 years and born 1930–1989 formed the analytical population. BMI was transformed to age‐specific z scores. Using linear spline multilevel models, each girl's BMI growth trajectory was estimated as the deviance from the average trajectory for three different growth periods (6.25–7.99, 8.0–10.99, 11.0–14.0 years). Via a link to health registers, 1,020 endometrial cancer cases were identified, and Cox regressions were performed. A greater gain in BMI during childhood was positively associated with endometrial cancer but no differences between the different growth periods were detected in models adjusted for baseline BMI. The hazard ratios for the associations with overall growth during childhood per 0.1 z score increase were 1.15 (95% confidence interval [CI]: 1.07–1.24) for all endometrial cancers, 1.12 (95% CI: 1.04–1.21) for estrogen‐dependent cancers, 1.16 (95% CI: 1.06–1.26) for endometrioid adenocarcinomas and 1.46 (95% CI: 1.16–1.84) for non‐estrogen‐dependent cancers. Growth in BMI in early life is positively linked to later endometrial cancer risk. We did not identify any sensitive childhood growth period, which suggests that excess gain in BMI during the entire childhood period should be avoided. PMID:27718528

  5. Growth curve trajectories of distress in burn patients.

    PubMed

    Mason, Shawn T; Corry, Nida; Gould, Neda F; Amoyal, Nicole; Gabriel, Vincent; Wiechman-Askay, Shelly; Holavanahalli, Radha; Banks, Sean; Arceneaux, Lisa; Fauerbach, James A

    2010-01-01

    Psychological adjustment after a major burn injury is a significant concern to providers and patients alike. Although efforts have been made to identify associated risk factors, little is known about heterogeneity in the levels or trajectories of adjustment in this population. This study used a novel application of Growth Mixture Modeling to identify subgroups of patients based on their longitudinal self-reported distress using the Brief Symptom Inventory (BSI). Data were drawn from the database of the Burn Model Systems project, a prospective, multisite, cohort study of major burn injury survivors. The BSI was used to assess symptoms in-hospital and at 6, 12, and 24 months postburn. Participants' T scores on the BSIs Global Severity Index provided a continuous measure of psychological distress. Analyses were conducted using participants' Global Severity Index T scores to discern distinct classes of respondents with similar trajectories across the 2-year follow-up. Results from the Growth Mixture Modeling analysis produced an ordered four-class model of psychological recovery from a major burn. Groups represented the equivalent of high, subthreshold, mild, and minimal symptom severity. Covariates significantly affected the intercept and slope of each class, as well as prediction of group assignment. These analyses demonstrate differences between individual recoveries after a major burn. Psychological distress symptoms remain largely stable over time and highlight the psychological vulnerability of this patient population.

  6. Helical growth trajectories in plant roots interacting with stiff barriers

    NASA Astrophysics Data System (ADS)

    Gerbode, Sharon; Noar, Roslyn; Harrison, Maria

    2009-03-01

    Plant roots successfully navigate heterogeneous soil environments with varying nutrient and water concentrations, as well as a variety of stiff obstacles. While it is thought that the ability of roots to penetrate into a stiff lower soil layer is important for soil erosion, little is known about how a root actually responds to a rigid interface. We have developed a laser sheet imaging technique for recording the 3D growth dynamics of plant roots interacting with stiff barriers. We find that a root encountering an angled interface does not grow in a straight line along the surface, but instead follows a helical trajectory. These experiments build on the pioneering studies of roots grown on a tilted 2D surface, which reported ``root waving,'' a similar curved pattern thought to be caused by the root's sensitivity to both gravity and the rigid surface on which it is grown. Our measurements extend these results to the more physiologically relevant case of 3D growth, where the spiral trajectory can be altered by tuning the relative strengths of the gravity and touch stimuli, providing some intuition for the physical mechanism driving it.

  7. Early life growth trajectories and future risk for overweight

    PubMed Central

    Jones-Smith, J C; Neufeld, L M; Laraia, B; Ramakrishnan, U; Garcia-Guerra, A; Fernald, L C H

    2013-01-01

    Objective: Standard approaches have found that rapid growth during the first 2 years of life is a risk factor for overweight in later childhood. Our objective was to test whether growth velocity, independent of concurrent size, was associated with overweight using a nonlinear random-effects model that allows for enhanced specifications and estimations. Methods: Longitudinal data from a birth cohort in Mexico (n=586) were used to estimate growth trajectories over 0–24 months for body mass index (BMI), length and weight using the SuperImposition by Translation and Rotation (SITAR) models. The SITAR models use a nonlinear random-effects model to estimate an average growth curve for BMI, length and weight and each participant's deviation from this curve on three dimensions—size, velocity and timing of peak velocity. We used logistic regression to estimate the association between overweight status at 7–9 years and size, velocity and timing of BMI, length and weight trajectories during 0–24 months. We tested whether any association between velocity and overweight varied by relative size during 0–24 months or birth weight. Results: SITAR models explained the majority of the variance in BMI (73%), height (86%) and weight (85%) between 0–24 months. When analyzed individually, relative BMI/length/weight (size) and BMI/length/weight velocity during 0–24 months were each associated with increased odds of overweight in late childhood. Associations for timing of peak velocity varied by anthropometric measure. However, in the mutually adjusted models, only relative BMI/length/weight (size) remained statistically significant. We found no evidence that any association between velocity and overweight varied by size during 0–24 months or birth weight. Conclusions: After mutual adjustment, size during 0–24 months of life (as opposed to birth size), but not velocity or timing of peak velocity, was most consistently associated with overweight in later childhood. PMID

  8. Trajectories of Discrimination Across Adolescence: Associations With Academic, Psychological, and Behavioral Outcomes.

    PubMed

    Hughes, Diane; Del Toro, Juan; Harding, Jessica F; Way, Niobe; Rarick, Jason R D

    2016-09-01

    The authors explored trajectories of perceived discrimination over a 6-year period (five assessments in 6th-11th grade) in relation to academic, behavioral, and psychological adjustment in 8th and 11th grades. They distinguished discrimination from adults versus peers in addition to overt versus covert discrimination from peers. The sample included 226 African American, White, Dominican, Puerto Rican, and Chinese adolescents (ages 11-12 at Time 1) recruited in sixth grade from six public schools in New York City. All forms of discrimination increased during middle school and decreased during high school. The frequency with which adolescents reported different sources and types of discrimination varied across ethnicity/race, but not gender. Initial levels and rates of change in discrimination predicted academic, behavioral, and psychological adjustment in 8th and 11th grades, albeit in complex ways.

  9. Effects of Family Structure Type and Stability on Children's Academic Performance Trajectories

    ERIC Educational Resources Information Center

    Sun, Yongmin; Li, Yuanzhang

    2011-01-01

    Using five waves of panel data from 8,008 children in the ECLS-K, the current study compared children's academic performance growth curves from kindergarten through fifth grade among three types of nondisrupted and three types of disrupted families. The analyses found that children in nondisrupted two-biological-parent and nondisrupted stepparent…

  10. Towards analysis of growth trajectory through multimodal longitudinal MR imaging

    NASA Astrophysics Data System (ADS)

    Sadeghi, Neda; Prastawa, Marcel; Gilmore, John H.; Lin, Weili; Gerig, Guido

    2010-03-01

    The human brain undergoes significant changes in the first few years after birth, but knowledge about this critical period of development is quite limited. Previous neuroimaging studies have been mostly focused on morphometric measures such as volume and shape, although tissue property measures related to the degree of myelination and axon density could also add valuable information to our understanding of brain maturation. Our goal is to complement brain growth analysis via morphometry with the study of longitudinal tissue property changes as reflected in patterns observed in multi-modal structural MRI and DTI. Our preliminary study includes eight healthy pediatric subjects with repeated scans at the age of two weeks, one year, and two years with T1, T2, PD, and DT MRI. Analysis is driven by the registration of multiple modalities and time points within and between subjects into a common coordinate frame, followed by image intensity normalization. Quantitative tractography with diffusion and structural image parameters serves for multi-variate tissue analysis. Different patterns of rapid changes were observed in the corpus callosum and the posterior and anterior internal capsule, structures known for distinctly different myelination growth. There are significant differences in central versus peripheral white matter. We demonstrate that the combined longitudinal analysis of structural and diffusion MRI proves superior to individual modalities and might provide a better understanding of the trajectory of early neurodevelopment.

  11. Repositioning an Academic Department to Stimulate Growth

    ERIC Educational Resources Information Center

    Elrod, Cassandra C.; Daughton, William J.; Murray, Susan L.; Fisher, Caroline M.; Flachsbart, Barry B.

    2011-01-01

    The complexity of the market in higher education, and the lack of literature regarding marketing, particularly branding, at the academic department level, presented an opportunity to establish a systematic process for evaluating an academic department's brand meaning. A process for evaluating a brand's meaning for an academic department is…

  12. The Impact of Race and Socioeconomic Status on the Reading Comprehension Growth Trajectories of Adolescents

    ERIC Educational Resources Information Center

    Pickens, Tyra W.

    2016-01-01

    The purpose of the current study was to examine features of adolescent reading comprehension trajectories and make within-person and between-person analyses of growth that occurs during the high school grades. Racial and socioeconomic group differences of the adolescent reading trajectories were also investigated and compared. This examination…

  13. Association Between Early Life Growth and Blood Pressure Trajectories in Black South African Children.

    PubMed

    Kagura, Juliana; Adair, Linda S; Munthali, Richard J; Pettifor, John M; Norris, Shane A

    2016-11-01

    Early growth is associated with blood pressure measured on one occasion, but whether early life growth patterns are associated with longitudinal blood pressure trajectories is under-researched. Therefore, we sought to examine the association between early growth and blood pressure trajectories from childhood to adulthood. Blood pressure was measured on 7 occasions between ages 5 and 18 years in the Birth to Twenty cohort study, and conditional variables for growth in infancy and mid-childhood were computed from anthropometric measures (n=1937, 52% girls). We used a group-based trajectory modeling approach to identify distinct height-adjusted blood pressure trajectories and then tested their association with growth between birth and mid-childhood adjusting for several covariates. Three trajectory groups were identified for systolic and diastolic blood pressure: lower, middle, and upper in boys and girls, separately. In boys, predictors of the middle or upper systolic blood pressure trajectories versus the lower trajectory were in birth weight (odds ratio 0.75 [95% confidence interval 0.58-0.96] per SD) and relative weight gain in infancy (4.11 [1.25-13.51] per SD). In girls, greater relative weight gain and linear growth in both infancy and mid-childhood were consistently associated with an almost 2-fold higher likelihood of being in the upper versus lower systolic blood pressure trajectory. The associations for the diastolic blood pressure trajectories were inconsistent. These findings emphasize the importance of identifying children at risk of progression to high blood pressure. Accelerated growth in infancy and mid-childhood may be a key target for early life intervention in prevention of elevated blood pressure progression.

  14. Prey behaviour across antipredator adaptation types: how does growth trajectory influence learning of predators?

    PubMed

    Ferrari, Maud C O; Brown, Grant E; Bortolotti, Gary R; Chivers, Douglas P

    2011-11-01

    Despite the fact that the ability of animals to avoid being consumed by predators is influenced by their behaviour, morphology and life history, very few studies have attempted to integrate prey responses across these adaptation types. Here, our goal was to address the link between life-history traits (size and growth trajectory) of tadpoles and behavioural responses to predators. Specifically, we wanted to determine whether information learned about predators was influenced by prey growth trajectory before and after learning. We manipulated the size/growth trajectory of tadpoles by raising them under different temperatures. Tadpoles raised on a slow-growth trajectory (under cold conditions) and taught to recognize a salamander subsequently showed stronger responses after 2 weeks than tadpoles that were raised on a fast-growth trajectory (under warm conditions). When we account for the effect of size (r (2)=0.22) on the responses of prey to predator cues, we find that the growth trajectory pre-learning but not post-learning influences the learned responses of the tadpoles. The differences in responses to predators may reflect differential memory associated with the predator. To our knowledge, this is the first study that has attempted to link life-history traits (size and growth rate) with learning of predators. In order to gain a comprehensive understanding of antipredator responses of prey animals, we call for additional integrative studies that examine prey anti-predator responses across adaptation types.

  15. Developmental Growth Trajectories in Understanding of Fraction Magnitude from Fourth through Sixth Grade

    ERIC Educational Resources Information Center

    Resnick, Ilyse; Jordan, Nancy C.; Hansen, Nicole; Rajan, Vinaya; Rodrigues, Jessica; Siegler, Robert S.; Fuchs, Lynn S.

    2016-01-01

    Development of fraction number line estimation was assessed longitudinally over 5 time points between 4th and 6th grades. Although students showed positive linear growth overall, latent class growth analyses revealed 3 distinct growth trajectory classes: Students who were highly accurate from the start and became even more accurate (n = 154);…

  16. Developmental Growth Trajectories in Understanding of Fraction Magnitude from Fourth through Sixth Grade

    ERIC Educational Resources Information Center

    Resnick, Ilyse; Jordan, Nancy C.; Hansen, Nicole; Rajan, Vinaya; Rodrigues, Jessica; Siegler, Robert S.; Fuchs, Lynn S.

    2016-01-01

    Development of fraction number line estimation was assessed longitudinally over five time points between fourth and sixth grades. Although students showed positive linear growth overall, latent class growth analyses revealed three distinct growth trajectory classes: Students who were highly accurate from the start and became even more accurate (n…

  17. Small Size at Birth or Abnormal Intrauterine Growth Trajectory: Which Matters More for Child Growth?

    PubMed

    Hutcheon, Jennifer A; Jacobsen, Geir W; Kramer, Michael S; Martinussen, Marit; Platt, Robert W

    2016-06-15

    Small size at birth is linked with lifelong adverse health implications. However, small size is only a proxy for the pathological process of interest, intrauterine growth restriction. We examined the extent to which information on intrauterine growth patterns improved prediction of childhood anthropometry, above and beyond birth weight alone. We obtained fetal weights estimated via serial ultrasound for 478 children in the Scandinavian Successive Small-for-Gestational-Age Births Study (1986-1988). Size at birth was classified using birth weight-for-gestational-age z scores and conditional fetal growth z scores (reflecting growth between 25 weeks' gestation and birth) using internal references. Conditional z scores were also expressed as residuals of birth weight z scores. Growth measures were linked with age-5-years anthropometric characteristics using linear regression. In univariable analyses, conditional fetal growth z scores were positively associated with z scores for child height, body mass index, total skinfold thickness, and head circumference (β = 0.24 (95% confidence interval (CI): 0.18, 0.31), β = 0.16 (95% CI: 0.09, 0.23), β = 0.08 (95% CI: 0.01, 0.16), and β = 0.37 (95% CI: 0.22, 0.52), respectively). However, conditional z scores were highly correlated with birth weight z scores (r = 0.9), and residuals explained minimal additional variation in anthropometric factors (null coefficients; adjusted R(2) increases < 0.01). Information on the intrauterine trajectory through which birth weight was attained provided little additional insight into child growth beyond that obtained from absolute size at birth.

  18. Additive genetic variance and developmental plasticity in growth trajectories in a wild cooperative mammal.

    PubMed

    Huchard, E; Charmantier, A; English, S; Bateman, A; Nielsen, J F; Clutton-Brock, T

    2014-09-01

    Individual variation in growth is high in cooperative breeders and may reflect plastic divergence in developmental trajectories leading to breeding vs. helping phenotypes. However, the relative importance of additive genetic variance and developmental plasticity in shaping growth trajectories is largely unknown in cooperative vertebrates. This study exploits weekly sequences of body mass from birth to adulthood to investigate sources of variance in, and covariance between, early and later growth in wild meerkats (Suricata suricatta), a cooperative mongoose. Our results indicate that (i) the correlation between early growth (prior to nutritional independence) and adult mass is positive but weak, and there are frequent changes (compensatory growth) in post-independence growth trajectories; (ii) among parameters describing growth trajectories, those describing growth rate (prior to and at nutritional independence) show undetectable heritability while associated size parameters (mass at nutritional independence and asymptotic mass) are moderately heritable (0.09 ≤ h(2) < 0.3); and (iii) additive genetic effects, rather than early environmental effects, mediate the covariance between early growth and adult mass. These results reveal that meerkat growth trajectories remain plastic throughout development, rather than showing early and irreversible divergence, and that the weak effects of early growth on adult mass, an important determinant of breeding success, are partly genetic. In contrast to most cooperative invertebrates, the acquisition of breeding status is often determined after sexual maturity and strongly impacted by chance in many cooperative vertebrates, who may therefore retain the ability to adjust their morphology to environmental changes and social opportunities arising throughout their development, rather than specializing early.

  19. How Well Does Growth Mixture Modeling Identify Heterogeneous Growth Trajectories? A Simulation Study Examining GMM's Performance Characteristics

    ERIC Educational Resources Information Center

    Peugh, James; Fan, Xitao

    2012-01-01

    Growth mixture modeling (GMM) has become a more popular statistical method for modeling population heterogeneity in longitudinal data, but the performance characteristics of GMM enumeration indexes in correctly identifying heterogeneous growth trajectories are largely unknown. Few empirical studies have addressed this issue. This study considered…

  20. A logistic mixture model for characterizing genetic determinants causing differentiation in growth trajectories.

    PubMed

    Wu, Rongling; Ma, Chang-Xing; Littell, Ramon C; Wu, Sameul S; Yin, Tongmingyin; Huang, Minren; Wang, Mingxiu; Casella, George

    2002-06-01

    The logistic or S-shaped curve of growth is one of the few universal laws in biology. It is certain that there exist specific genes affecting growth curves, but, due to a lack of statistical models, it is unclear how these genes cause phenotypic differentiation in growth and developmental trajectories. In this paper we present a statistical model for detecting major genes responsible for growth trajectories. This model is incorporated with pervasive logistic growth curves under the maximum likelihood framework and, thus, is expected to improve over previous models in both parameter estimation and inference. The power of this model is demonstrated by an example using forest tree data, in which evidence of major genes affecting stem growth processes is successfully detected. The implications for this model and its extensions are discussed.

  1. Trajectories of Posttraumatic Growth and Associated Characteristics in Women with Breast Cancer

    PubMed Central

    Danhauer, Suzanne C.; Russell, Greg; Case, L. Douglas; Sohl, Stephanie J.; Tedeschi, Richard G.; Addington, Elizabeth L.; Triplett, Kelli; Van Zee, Kimberly J.; Naftalis, Elizabeth Z.; Levine, Beverly; Avis, Nancy E.

    2015-01-01

    Background Cancer survivors may experience posttraumatic growth (PTG), positive psychological changes resulting from highly stressful events; however, the longitudinal course of PTG is poorly understood. Purpose To determine trajectories of PTG in breast cancer survivors and associated characteristics. Methods Women (N=653) participating in a longitudinal observational study completed questionnaires within 8 months of breast cancer diagnosis and 6, 12, and 18 months later. Group-based modeling identified PTG trajectories. Chi-square tests and ANOVA detected group differences in demographic, medical and psychosocial variables. Results Six trajectory groups emerged. Three were stable at different levels of PTG, two increased modestly, and one increased substantially over time. Trajectory groups differed by age, race, receipt of chemotherapy, illness intrusiveness, depressive symptoms, active-adaptive coping, and social support. Conclusions This first examination of PTG trajectories in US cancer survivors elucidates heterogeneity in longitudinal patterns of PTG. Future research should determine whether other samples exhibit similar trajectories and whether various PTG trajectories predict mental and physical health outcomes. PMID:25786706

  2. Modeling Math Growth Trajectory--An Application of Conventional Growth Curve Model and Growth Mixture Model to ECLS K-5 Data

    ERIC Educational Resources Information Center

    Lu, Yi

    2016-01-01

    To model students' math growth trajectory, three conventional growth curve models and three growth mixture models are applied to the Early Childhood Longitudinal Study Kindergarten-Fifth grade (ECLS K-5) dataset in this study. The results of conventional growth curve model show gender differences on math IRT scores. When holding socio-economic…

  3. The Role of Academic Achievement Growth in School Track Recommendations

    ERIC Educational Resources Information Center

    Caro, Daniel H.; Lenkeit, Jenny; Lehmann, Rainer; Schwippert, Knut

    2009-01-01

    Students in Germany are tracked into different forms of secondary schooling based on teachers' recommendations. The literature shows that school tracking is largely affected by academic achievement levels, but neglects the influence of individual achievement growth. The authors used data from the Berlin study ELEMENT (N = 2242) to characterize…

  4. Perinatal programming of childhood asthma: early fetal size, growth trajectory during infancy, and childhood asthma outcomes.

    PubMed

    Turner, Steve

    2012-01-01

    The "fetal origins hypothesis" or concept of "developmental programming" suggests that faltering fetal growth and subsequent catch-up growth are implicated in the aetiology of cardiovascular disease. Associations between reduced birth weight, rapid postnatal weight gain, and asthma suggest that there are fetal origins to respiratory disease. The present paper first summarises the literature relating birth weight and post natal growth trajectories to asthma outcomes. Second, issues regarding the interpretation of antenatal fetal ultrasound measurements are discussed. Finally, recent reports linking antenatal measurement and growth trajectory to early childhood asthma outcomes are discussed. Understanding the nature and timing of factors which influence antenatal growth may give important insight into the antecedents of early-onset asthma with implications for interventions.

  5. Deflecting the trajectory and changing the narrative: how self-affirmation affects academic performance and motivation under identity threat.

    PubMed

    Sherman, David K; Hartson, Kimberly A; Binning, Kevin R; Purdie-Vaughns, Valerie; Garcia, Julio; Taborsky-Barba, Suzanne; Tomassetti, Sarah; Nussbaum, A David; Cohen, Geoffrey L

    2013-04-01

    To the extent that stereotype and identity threat undermine academic performance, social psychological interventions that lessen threat could buffer threatened students and improve performance. Two studies, each featuring a longitudinal field experiment in a mixed-ethnicity middle school, examined whether a values affirmation writing exercise could attenuate the achievement gap between Latino American and European American students. In Study 1, students completed multiple self-affirmation (or control) activities as part of their regular class assignments. Latino American students, the identity threatened group, earned higher grades in the affirmation than control condition, whereas White students were unaffected. The effects persisted 3 years and, for many students, continued into high school by lifting their performance trajectory. Study 2 featured daily diaries to examine how the affirmation affected psychology under identity threat, with the expectation that it would shape students' narratives of their ongoing academic experience. By conferring a big-picture focus, affirmation was expected to broaden construals, prevent daily adversity from being experienced as identity threat, and insulate academic motivation from identity threat. Indeed, affirmed Latino American students not only earned higher grades than nonaffirmed Latino American students but also construed events at a more abstract than concrete level and were less likely to have their daily feelings of academic fit and motivation undermined by identity threat. Discussion centers on how social-psychological processes propagate themselves over time and how timely interventions targeting these processes can promote well-being and achievement.

  6. Trajectories of male sexual aggression from adolescence through college: A latent class growth analysis.

    PubMed

    Swartout, Kevin M; Swartout, Ashlyn G; Brennan, Carolyn L; White, Jacquelyn W

    2015-01-01

    Approximately 25% of male college students report engaging in some form of sexual coercion by the end of their fourth year of college. White and Smith (2004) found that negative childhood experiences-childhood sexual abuse, childhood physical abuse, and witnessing domestic violence-predicted sexual aggression perpetrated before college, but not during the subsequent college years, a puzzling finding in view of the reasonably consistent rates of sexual aggression from adolescence to the first 2 years of college. The current study takes a person-centered approach to sexual aggression in an attempt to resolve this discrepancy. We examined the possibility of cohesive subgroups of men in terms of their frequency of sexual aggression across the pre-college and college years. A series of latent class growth models were fit to an existing longitudinal dataset of sexual experiences collected across four time points-pre-college through year 3 of college. A four-trajectory model fit the data well, exhibiting significantly better fit than a three-trajectory model. The four trajectories are interpreted as men who perpetrate sexual aggression at (1) low (71.5% of the sample), (2) moderate (21.2%), (3) decreasing (4.2%), and (4) increasing (3.1%) frequencies across time. Negative childhood experiences predicted membership of the decreasing trajectory, relative to the low trajectory, but did not predict membership of the increasing trajectory, explaining the discrepancy uncovered by White and Smith. Implications for primary prevention of sexual aggression are discussed.

  7. High-Achieving and Average Students' Reading Growth: Contrasting School and Summer Trajectories

    ERIC Educational Resources Information Center

    Rambo-Hernandez, Karen E.; McCoach, D. Betsy

    2015-01-01

    Much is unknown about how initially high-achieving students grow academically, especially given the measurement issues inherent in assessing growth for the highest performing students. This study compared initially high-achieving and average students' growth in reading (in a cohort of third-grade students from 2,000 schools) over 3 years.…

  8. Reading and Math Achievement Profiles and Longitudinal Growth Trajectories of Children with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Wei, Xin; Christiano, Elizabeth R. A.; Yu, Jennifer W.; Wagner, Mary; Spiker, Donna

    2015-01-01

    This study examined the reading and math achievement profiles and longitudinal growth trajectories of a nationally representative sample of children ages 6 through 9 with an autism spectrum disorder. Four distinct achievement profiles were identified: higher-achieving (39%), hyperlexia (9%), hypercalculia (20%) and lower-achieving (32%). Children…

  9. Five-Year Growth Trajectories of Kindergarten Children with Learning Difficulties in Mathematics

    ERIC Educational Resources Information Center

    Morgan, Paul L.; Farkas, George; Wu, Qiong

    2009-01-01

    The investigators used data from the "Early Childhood Longitudinal Study-Kindergarten Cohort" (ECLS-K) to estimate whether and to what extent the timing and persistence of mathematics difficulties (MD) in kindergarten predicted children's first through fifth grade math growth trajectories. Results indicated that children persistently…

  10. Deep Processing Strategies and Critical Thinking: Developmental Trajectories Using Latent Growth Analyses

    ERIC Educational Resources Information Center

    Phan, Huy P.

    2011-01-01

    The author explored the developmental courses of deep learning approach and critical thinking over a 2-year period. Latent growth curve modeling (LGM) procedures were used to test and trace the trajectories of both theoretical frameworks over time. Participants were 264 (119 women, 145 men) university undergraduates. The Deep Learning subscale of…

  11. Timing and trajectories of fetal growth related to cognitive development in childhood.

    PubMed

    von Ehrenstein, Ondine S; Mikolajczyk, Rafael T; Zhang, Jun

    2009-12-01

    The authors investigated timing and trajectories of fetal growth in relation to childhood development in the National Institute of Child Health and Human Development-Scandinavian Study of Successive Small-for-Gestational Age Births (1986-1988) (n = 1,059). Fetal size was assessed by ultrasound at 17, 25, and 33 gestational weeks and at birth. Bayley Scales of Infant Development and the Wechsler Preschool and Primary Scale of Intelligence-Revised tests were conducted at ages 1 and 5 years, respectively, producing mental and psychomotor development indexes and verbal and performance intelligence quotients. Relative fetal size was calculated as a standard deviation score at each data point; growth trajectories were explored with longitudinal mixture models. Fetal size at 17, 25, and 33 weeks was positively associated with mental development index; larger size at 33 weeks and at birth was associated with higher verbal intelligence quotient scores (2.61, 95% confidence interval: 1.06, 4.15 and 1.90, 95% confidence interval: 0.67, 3.13 increase per 1 standard deviation score, respectively); findings were similar for performance intelligence quotient. Seven trajectories were identified; scores were lower for "small" and "medium-to-small" trajectories than for "medium" and "big" (representing normal size) trajectories: mental development index (P < 0.01), performance intelligence quotient (P < 0.001), and verbal intelligence quotient (P < 0.001). Overall, larger fetal size in the second and third trimesters was positively associated with childhood development. Fetal growth trajectories may matter beyond birth.

  12. Hailstone Growth Trajectories in the Dynamic Evolution of a Moderate Hailstorm.

    NASA Astrophysics Data System (ADS)

    Grenier, Jean-Claude; Admirat Sadok Zair, Pierre

    1983-06-01

    For the purpose of studying the growth environment of hailstones in a moderate storm, more than 200 hailstones, collected at several points along the storm path, were investigated by crystallographic and isotopic analysis. The majority of the embryos were frozen drops. The post-embryonic growth, generally observed in two growth layers, took place in a narrow range of altitudes. For six hailstones this range, inferred from isotopic data supported by a model accounting for entrainment, was between 5900 and 7100 m (11 to 19°C). The hailstone growth trajectories were in good agreement, in space and in time, with the cell dynamic evolution derived from radar data.

  13. Characterizing Resilience and Growth Among Soldiers: A Trajectory Study

    DTIC Science & Technology

    2013-10-01

    Accomplishments………………………………………….…….. 5 Reportable Outcomes ……………………………………………………………… 5 Conclusion…………………………………………………………………………… 6...will be the identification of specific intervention targets for resilience and growth training programs in the military that are conceptually...not continue with the project due to a profound grief. Therefore, we needed to hire and train new team members. Although we were committed to

  14. The shifting trajectory of growth in femur length during gestation.

    PubMed

    Bjørnerem, Ashild; Johnsen, Synnøve L; Nguyen, Tuan V; Kiserud, Torvid; Seeman, Ego

    2010-05-01

    Bone size is a determinant of bone strength and tracks in its percentile of origin during childhood and adolescence. We hypothesized that the ranking of an individual's femur length (FL) is established in early gestation and tracks thereafter. Fetal FL was measured serially using 2D ultrasound in 625 Norwegian fetuses. Tracking was assessed using Pearson correlation, a generalized estimating equation model, and by calculating the proportion of fetuses whose FL remained within the same quartile. Baseline FL Z-score (weeks 10 to 19) and later measurements correlated, but more weakly as gestation advanced: r = 0.59 (weeks 20 to 26); r = 0.45 (weeks 27 to 33); and r = 0.32 (weeks 34 to 39) (p < 0.001). Tracking within the same quartile throughout gestation occurred in 13% of fetuses. Of the 87% deviating, 21% returned to the quartile of origin, so 34% began and ended in the same quartile, 38% deviated by one quartile, and 28% deviated by two or more quartiles by the end of gestation. A standard deviation higher baseline FL Z-score, placental weight (150 g), maternal height (5 cm), and weight (10 kg), was associated with a 0.25, 0.15, 0.10, and 0.05 SD higher FL Z-score at the end of gestation, respectively (p ranging from <0.001 to 0.02). Tracking within the same percentile throughout the whole of gestation, as suggest by growth charts, is uncommon. Deviation from tracking is more common and is the result of changes in growth velocity within and between fetuses and is partly influenced by maternal, fetal, and placental factors.

  15. Identifying Finnish Children's Impulsivity Trajectories from Kindergarten to Grade 4: Associations with Academic and Socioemotional Development

    ERIC Educational Resources Information Center

    Hirvonen, Riikka; Poikkeus, Anna-Maija; Pakarinen, Eija; Lerkkanen, Marja-Kristiina; Nurmi, Jari-Erik

    2015-01-01

    Research Findings: The purpose of this study was to identify the developmental trajectories of impulsive behavior among 378 Finnish children who were followed from kindergarten to 4th grade. In addition to ratings of children's impulsivity, the analyses included measures of motivation, cognitive skills, socioemotional adjustment, and…

  16. Academically Elite Students in Singapore: A Collective Moral Stance toward Aspirations and Trajectories

    ERIC Educational Resources Information Center

    Lu, Luke

    2016-01-01

    This paper draws on a Linguistic Ethnography (Blommaert & Rampton 2011) of a group of academically elite students in Singapore. The group comprises locals born in Singapore, as well as immigrants from China and Vietnam. My informants all attended a top-ranked secondary school in Singapore. I present data from interviews and a focus group…

  17. Stay in the Game: Gender, Family Formation and Alternative Trajectories in the Academic Life Course

    ERIC Educational Resources Information Center

    Wolfinger, Nicholas H.; Mason, Mary Ann; Goulden, Marc

    2009-01-01

    Academic careers have traditionally been conceptualized as pipelines, through which young scholars move seamlessly from graduate school to tenure-track positions. This model often fails to capture the experiences of female Ph.D. recipients, who become tenure-track assistant professors at lower rates than do their male counterparts. What do these…

  18. Parents' Conceptions of School Readiness, Transition Practices, and Children's Academic Achievement Trajectories

    ERIC Educational Resources Information Center

    Puccioni, Jaime

    2015-01-01

    The author empirically tests the conceptual model of academic socialization, which suggests that parental cognitions about schooling influence parenting practices and child outcomes during the transition to school (Taylor, Clayton, & Rowley, 2004). More specifically, the author examines associations among parents' conceptions of school…

  19. L2 Academic Discourse Socialization through Oral Presentations: An Undergraduate Student's Learning Trajectory in Study Abroad

    ERIC Educational Resources Information Center

    Kobayashi, Masaki

    2016-01-01

    The present study provides an in-depth, longitudinal account of an undergraduate student's L2 discourse socialization in an academic exchange program in Canada. By invoking Rogoff's (1995) notion of participatory appropriation, this qualitative case study examined an L2 student's task-related strategies and performance as they evolved over time in…

  20. Year of the Woman, Decade of the Man: trajectories of growth in women's state legislative representation.

    PubMed

    Paxton, Pamela; Painter, Matthew A; Hughes, Melanie M

    2009-03-01

    The expansion of women's political representation ranks among the most significant trends in American politics of the last 100 years. In this paper, we develop two longitudinal theories to explain patterns of growth and change in women's state legislative representation over time. Gender salience suggests that years in which women's absence from politics is problematized (e.g., 1992-the Year of the Woman) will demonstrate higher levels of growth. Political climate suggests that periods in which domestic issues are stressed (e.g., the 1990s) will produce higher levels of growth than periods in which international issues are stressed (e.g., post 9/11). Combinations of these two theories create four possible trajectories of growth in women's representation that may be observed over time. We use latent growth curve models to assess the four theoretical trajectories, using data on women's state legislative representation from 1982 to 2006. We find that while women achieved fleeting success in the Year of the Woman, further gains were limited in the remainder of the 1990s and average growth stalled completely after 2001. Our results show futher that gender salience and, to a lesser extent political, climate matter to growth and change in women's political power over time.

  1. Growth mindset tempers the effects of poverty on academic achievement.

    PubMed

    Claro, Susana; Paunesku, David; Dweck, Carol S

    2016-08-02

    Two largely separate bodies of empirical research have shown that academic achievement is influenced by structural factors, such as socioeconomic background, and psychological factors, such as students' beliefs about their abilities. In this research, we use a nationwide sample of high school students from Chile to investigate how these factors interact on a systemic level. Confirming prior research, we find that family income is a strong predictor of achievement. Extending prior research, we find that a growth mindset (the belief that intelligence is not fixed and can be developed) is a comparably strong predictor of achievement and that it exhibits a positive relationship with achievement across all of the socioeconomic strata in the country. Furthermore, we find that students from lower-income families were less likely to hold a growth mindset than their wealthier peers, but those who did hold a growth mindset were appreciably buffered against the deleterious effects of poverty on achievement: students in the lowest 10th percentile of family income who exhibited a growth mindset showed academic performance as high as that of fixed mindset students from the 80th income percentile. These results suggest that students' mindsets may temper or exacerbate the effects of economic disadvantage on a systemic level.

  2. Growth mindset tempers the effects of poverty on academic achievement

    PubMed Central

    Claro, Susana; Paunesku, David; Dweck, Carol S.

    2016-01-01

    Two largely separate bodies of empirical research have shown that academic achievement is influenced by structural factors, such as socioeconomic background, and psychological factors, such as students’ beliefs about their abilities. In this research, we use a nationwide sample of high school students from Chile to investigate how these factors interact on a systemic level. Confirming prior research, we find that family income is a strong predictor of achievement. Extending prior research, we find that a growth mindset (the belief that intelligence is not fixed and can be developed) is a comparably strong predictor of achievement and that it exhibits a positive relationship with achievement across all of the socioeconomic strata in the country. Furthermore, we find that students from lower-income families were less likely to hold a growth mindset than their wealthier peers, but those who did hold a growth mindset were appreciably buffered against the deleterious effects of poverty on achievement: students in the lowest 10th percentile of family income who exhibited a growth mindset showed academic performance as high as that of fixed mindset students from the 80th income percentile. These results suggest that students’ mindsets may temper or exacerbate the effects of economic disadvantage on a systemic level. PMID:27432947

  3. The Role of Institutional, Family and Peer-Based Discourses and Practices in the Construction of Students' Socio-Academic Trajectories

    ERIC Educational Resources Information Center

    Poveda, David; Jociles, Maria Isabel; Franze, Adela; Moscoso, Maria Fernanda; Calvo, Albano

    2012-01-01

    In this article, we discuss findings from multi-level ethnography conducted in a secondary school located in Madrid (Spain). The study focuses on the variety of institutional, family and peer-based factors that contribute to the construction of students' socio-academic trajectories. In particular, we attempt to understand the role these social…

  4. A Growth Model for Academic Program Life Cycle (APLC): A Theoretical and Empirical Analysis

    ERIC Educational Resources Information Center

    Acquah, Edward H. K.

    2010-01-01

    Academic program life cycle concept states each program's life flows through several stages: introduction, growth, maturity, and decline. A mixed-influence diffusion growth model is fitted to enrolment data on academic programs to analyze the factors determining progress of academic programs through their life cycles. The regression analysis yield…

  5. Urban Growth Detection Using Filtered Landsat Dense Time Trajectory in an Arid City

    NASA Astrophysics Data System (ADS)

    Ye, Z.; Schneider, A.

    2014-12-01

    Among all remote sensing environment monitoring techniques, time series analysis of biophysical index is drawing increasing attention. Although many of them studied forest disturbance and land cover change detection, few focused on urban growth mapping at medium spatial resolution. As Landsat archive becomes open accessible, methods using Landsat time-series imagery to detect urban growth is possible. It is found that a time trajectory from a newly developed urban area shows a dramatic drop of vegetation index. This enable the utilization of time trajectory analysis to distinguish impervious surface and crop land that has a different temporal biophysical pattern. Also, the time of change can be estimated, yet many challenges remain. Landsat data has lower temporal resolution, which may be worse when cloud-contaminated pixels and SLC-off effect exist. It is difficult to tease apart intra-annual, inter-annual, and land cover difference in a time series. Here, several methods of time trajectory analysis are utilized and compared to find a computationally efficient and accurate way on urban growth detection. A case study city, Ankara, Turkey is chosen for its arid climate and various landscape distributions. For preliminary research, Landsat TM and ETM+ scenes from 1998 to 2002 are chosen. NDVI, EVI, and SAVI are selected as research biophysical indices. The procedure starts with a seasonality filtering. Only areas with seasonality need to be filtered so as to decompose seasonality and extract overall trend. Harmonic transform, wavelet transform, and a pre-defined bell shape filter are used to estimate the overall trend in the time trajectory for each pixel. The point with significant drop in the trajectory is tagged as change point. After an urban change is detected, forward and backward checking is undertaken to make sure it is really new urban expansion other than short time crop fallow or forest disturbance. The method proposed here can capture most of the urban

  6. Academic Achievement Trajectories of Homeless and Highly Mobile Students: Resilience in the Context of Chronic and Acute Risk

    PubMed Central

    Cutuli, J. J.; Desjardins, Christopher David; Herbers, Janette E.; Long, Jeffrey D.; Heistad, David; Chan, Chi-Keung; Hinz, Elizabeth; Masten, Ann S.

    2012-01-01

    Analyses examined academic achievement data across 3rd through 8th grades (N = 26,474), comparing students identified as homeless or highly mobile (HHM) to other students in the federal free meal program (FM), reduced-price meals (RM), or neither (General). Achievement was lower as a function of rising risk status (General > RM > FM > HHM). Achievement gaps appeared stable or widened between HHM students and lower-risk groups. Math and reading achievement were lower and growth in math was slower in years of HHM identification, suggesting acute consequences of residential instability. Nonetheless, 45% of HHM students scored within or above the average range, suggesting academic resilience. Results underscore the need for research on risk and resilience processes among HHM students to address achievement disparities. PMID:23110492

  7. Self-esteem growth trajectory from adolescence to mid-adulthood and its predictors in adolescence.

    PubMed

    Kiviruusu, Olli; Huurre, Taina; Aro, Hillevi; Marttunen, Mauri; Haukkala, Ari

    2015-03-01

    The present study examined the trajectory of self-esteem from adolescence to mid-adulthood and its predictors in adolescence in a prospective cohort sample with a 26-year follow-up. Participants of a Finnish cohort study in 1983 at 16 years (N = 2194) were followed up at ages 22 (N = 1656), 32 (N = 1471) and 42 (N = 1334) years. Self-esteem development was analyzed using latent growth curve models with parental socioeconomic status (SES), parental divorce, school achievement, daily smoking, and heavy drinking as time invariant covariates. Self-esteem grew linearly from 16 to 32 years, but stabilized after that with no growth between 32 and 42 years. Males had significantly higher self-esteem throughout the follow-up, although females had a faster growth rate. Better school performance and higher parental SES were associated with a higher initial level of self-esteem among both genders, while parental divorce among females and daily smoking among males were associated with a lower initial level of self-esteem. Among females the growth rate of self-esteem was practically unaffected by the studied covariates. Among males, however, the initial differences in self-esteem favouring those from a higher SES background were indicated to diminish, while the differences between non-smokers and smokers were indicated to increase. The studied adolescent covariates combined had only limited predictive value for the later self-esteem development. However, the effects of any covariate on the level and slope of the self-esteem trajectory, even if small, should be assessed in combination in order to identify whether they lead to converging, diverging or constantly equidistant self-esteem trajectories. The findings highlight the variety of roles that adolescent behaviours and social environments may have in the developmental process of self-esteem from adolescence into mid-adulthood.

  8. Canadian Youths' Trajectories of Psychosocial Competencies through University: Academic and Romantic Affairs Matter

    ERIC Educational Resources Information Center

    Lascano, Dayuma Ixchel Vargas; Galambos, Nancy L.; Hoglund, Wendy L.

    2014-01-01

    The increasingly prolonged transition to adulthood has raised concerns about the nature and timing of growth in the attainment of important psychosocial competencies in young people. Changes over time in self-reported competencies (work orientation, identity, intimacy) were examined in 198 Canadians, who were followed for the first 4 years of…

  9. Growth trajectories of early aggression, overactivity, and inattention: Relations to second-grade reading.

    PubMed

    Gray, Sarah A O; Carter, Alice S; Briggs-Gowan, Margaret J; Jones, Stephanie M; Wagmiller, Robert L

    2014-09-01

    The link between behavior problems and low academic achievement is well established, but few studies have examined longitudinal relations between early externalizing behaviors before school entry and low academic achievement following transition to formal schooling. Early inattention has been particularly overlooked, despite strong associations between inattention and reading difficulties later in development. Trajectories of infant and toddler aggression, overactivity, and inattention, developed from parent reports about 1- to 3-year-old children, were examined as predictors of direct assessments of 2nd-grade reading in an at-risk epidemiological study subsample (N = 359). Reports of inattentive and overactive behaviors at ages 1-3 years and changes in inattention through toddlerhood predicted reading achievement in 2nd grade. A parallel process model suggested that the effects of early inattention on reading appear to be most robust. Findings underscore the contribution of social-emotional development to school readiness and the importance of early identification of children with externalizing problems, as early interventions designed to reduce externalizing problems may improve later reading skills.

  10. Accurate estimates of age at maturity from the growth trajectories of fishes and other ectotherms.

    PubMed

    Honsey, Andrew E; Staples, David F; Venturelli, Paul A

    2017-01-01

    Age at maturity (AAM) is a key life history trait that provides insight into ecology, evolution, and population dynamics. However, maturity data can be costly to collect or may not be available. Life history theory suggests that growth is biphasic for many organisms, with a change-point in growth occurring at maturity. If so, then it should be possible to use a biphasic growth model to estimate AAM from growth data. To test this prediction, we used the Lester biphasic growth model in a likelihood profiling framework to estimate AAM from length at age data. We fit our model to simulated growth trajectories to determine minimum data requirements (in terms of sample size, precision in length at age, and the cost to somatic growth of maturity) for accurate AAM estimates. We then applied our method to a large walleye Sander vitreus data set and show that our AAM estimates are in close agreement with conventional estimates when our model fits well. Finally, we highlight the potential of our method by applying it to length at age data for a variety of ectotherms. Our method shows promise as a tool for estimating AAM and other life history traits from contemporary and historical samples.

  11. Trajectories of adolescent substance use development and the influence of healthy leisure: A growth mixture modeling approach.

    PubMed

    Weybright, Elizabeth H; Caldwell, Linda L; Ram, Nilam; Smith, Edward A; Wegner, Lisa

    2016-06-01

    Considerable heterogeneity exists in adolescent substance use development. To most effectively prevent use, distinct trajectories of use must be identified as well as differential associations with predictors of use, such as leisure experience. The current study used a person-centered approach to identify distinct substance use trajectories and how leisure is associated with trajectory classes. Data came from a larger efficacy trial of 2.249 South African high school students who reported substance use at any time across 8 waves. Growth mixture modeling was used to identify developmental trajectories of substance use and the influence of healthy leisure. Results identified three increasing and one stable substance use trajectory and subjective healthy leisure served to protect against use. This study is the first of its kind to focus on a sample of South African adolescents and serves to develop a richer understanding of substance use development and the role of healthy leisure.

  12. Academic and Workplace-related Visual Stresses Induce Detectable Deterioration Of Performance, Measured By Basketball Trajectories and Astigmatism Impacting Athletes Or Students In Military Pilot Training.

    NASA Astrophysics Data System (ADS)

    Mc Leod, Roger D.

    2004-03-01

    Separate military establishments across the globe can confirm that a high percentage of their prospective pilots-in-training are no longer visually fit to continue the flight training portion of their programs once their academic coursework is completed. I maintain that the visual stress induced by those intensive protocols can damage the visual feedback mechanism of any healthy and dynamic system beyond its usual and ordinary ability to self-correct minor visual loss of acuity. This deficiency seems to be detectable among collegiate and university athletes by direct observation of the height of the trajectory arc of a basketball's flight. As a particular athlete becomes increasingly stressed by academic constraints requiring long periods of concentrated reading under highly static angular convergence of the eyes, along with unfavorable illumination and viewing conditions, eyesight does deteriorate. I maintain that induced astigmatism is a primary culprit because of the evidence of that basketball's trajectory! See the next papers!

  13. Trajectories of growth in body mass index across childhood: Associations with maternal and paternal employment.

    PubMed

    Morrissey, Taryn W

    2013-10-01

    Research links mothers' employment to higher body mass index (BMI), a measure of weight-for-height, among their children. However, how maternal employment patterns relate to their children's BMI trajectories, and the role that fathers' employment plays in when and at what rate children grow, remain unclear. With data on children from 2 to 15 years of age living in two-parent families from the U.S. NICHD's Study of Early Child Care and Youth Development (N = 1107), individual growth models are used to describe American children's BMI trajectories as predicted by maternal and paternal employment characteristics. Results indicate that, by age 15, children's BMIs are, on average, nearly one-half of a standard deviation above recommended levels, and the majority of growth occurs during the preschool period. The duration of maternal employment, and combined measures of maternal and paternal employment duration, are both associated with higher child BMI across childhood. Associations are small but cumulative. Notably, the association between the duration of time children lived in dual-earner families and child BMI is larger than that between maternal employment duration alone and children's BMI, which is strongest during the preschool period. Combined measures of maternal and paternal employment intensity, defined as the number of periods both parents worked 35 or more hours per week, are associated with higher child BMI during the preschool period only. Findings highlight the importance of taking into account both parents' employment characteristics in investigating children's physical development.

  14. The contribution of feeding mode to obesogenic growth trajectories in American Samoan infants

    PubMed Central

    Hawley, Nicola L; Johnson, William; Nu’usolia, Ofeira; McGarvey, Stephen T

    2013-01-01

    Background Samoans are recognized for their particularly high body mass index and prevalent adult obesity but infants are understudied. Objective To examine the prevalence of overweight and obesity and determine the contribution of feeding mode to obesogenic growth trajectories in American Samoan infants. Methods Data were extracted from the well baby records of 795 (n=417 male) Samoan infants aged 0-15 months. Mixed-effects growth models were used to produce individual weight and length curves. Further mixed-effects models were fitted with feeding mode (breastfed, formula- or mixed-fed) as a single observation at age four (±2) months. Weight and length values were converted to Z-scores according to the CDC 2000 reference. Results At 15 months, 23.3% of boys and 16.7% of girls were obese (weight-for-length > 95th percentile). Feeding mode had a significant effect on weight and length trajectories. Formula-fed infants gained weight and length faster than breastfed infants. Formula-fed boys were significantly more likely to be obese at 15 months (38.6%) than breastfed boys (23.4%), χ2=8.4, P<0.01, odds ratio=2.05, 95% CI [1.04, 4.05]. Conclusion Obesity in American Samoans is not confined to adults. Obesity prevention efforts should be targeted at early life and promotion of breastfeeding may be a suitable intervention target. PMID:23386576

  15. Postdivorce Family Stability and Changes in Adolescents' Academic Performance: A Growth-Curve Model

    ERIC Educational Resources Information Center

    Sun, Yongmin; Li, Yuanzhang

    2009-01-01

    Three waves of panel data from 7,897 adolescents in the National Education Longitudinal Studies have been used to investigate whether a stabilized postdivorce family environment benefits adolescents' academic performance trajectories. The analyses indicate that compared with peers who grow up in stable postdivorce families, children of divorce who…

  16. Growth trajectory influences temperature preference in fish through an effect on metabolic rate.

    PubMed

    Killen, Shaun S

    2014-11-01

    Most animals experience temperature variations as they move through the environment. For ectotherms, in particular, temperature has a strong influence on habitat choice. While well studied at the species level, less is known about factors affecting the preferred temperature of individuals; especially lacking is information on how physiological traits are linked to thermal preference and whether such relationships are affected by factors such feeding history and growth trajectory. This study examined these issues in the common minnow Phoxinus phoxinus, to determine the extent to which feeding history, standard metabolic rate (SMR) and aerobic scope (AS), interact to affect temperature preference. Individuals were either: 1) food deprived (FD) for 21 days, then fed ad libitum for the next 74 days; or 2) fed ad libitum throughout the entire period. All animals were then allowed to select preferred temperatures using a shuttle-box, and then measured for SMR and AS at 10 °C, estimated by rates of oxygen uptake. Activity within the shuttle-box under a constant temperature regime was also measured. In both FD and control fish, SMR was negatively correlated with preferred temperature. The SMR of the FD fish was increased compared with the controls, probably due to the effects of compensatory growth, and so these growth-compensated fish preferred temperatures that were on average 2.85 °C cooler than controls fed a maintenance ration throughout the study. Fish experiencing compensatory growth also displayed a large reduction in activity. In growth-compensated fish and controls, activity measured at 10 °C was positively correlated with preferred temperature. Individual fish prefer temperatures that vary predictably with SMR and activity level, which are both plastic in response to feeding history and growth trajectories. Cooler temperatures probably allow individuals to reduce maintenance costs and divert more energy towards growth. A reduction in SMR at cooler

  17. Five-year growth trajectories of kindergarten children with learning difficulties in mathematics.

    PubMed

    Morgan, Paul L; Farkas, George; Qiong Wu

    2009-01-01

    The investigators used data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) to estimate whether and to what extent the timing and persistence of mathematics difficulties (MD) in kindergarten predicted children's first through fifth grade math growth trajectories. Results indicated that children persistently displaying MD (i.e., those experiencing MD in both fall and spring of kindergarten) had the lowest subsequent growth rates, children with MD in spring only had the second-lowest growth rates, and children with MD in the fall only (and who had thus recovered from their MD by the spring of kindergarten) had the next-lowest growth rates. The children who did not have MD in either fall or spring of kindergarten had the highest growth rates. These results were observed prior to and after statistical control for additional variables. They indicate that measuring the timing and persistence of kindergarten children's mathematics learning difficulties may help identify those most at risk for failing to become mathematically proficient during elementary school.

  18. Trajectories of acute low back pain: a latent class growth analysis.

    PubMed

    Downie, Aron S; Hancock, Mark J; Rzewuska, Magdalena; Williams, Christopher M; Lin, Chung-Wei Christine; Maher, Christopher G

    2016-01-01

    Characterising the clinical course of back pain by mean pain scores over time may not adequately reflect the complexity of the clinical course of acute low back pain. We analysed pain scores over 12 weeks for 1585 patients with acute low back pain presenting to primary care to identify distinct pain trajectory groups and baseline patient characteristics associated with membership of each cluster. This was a secondary analysis of the PACE trial that evaluated paracetamol for acute low back pain. Latent class growth analysis determined a 5 cluster model, which comprised 567 (35.8%) patients who recovered by week 2 (cluster 1, rapid pain recovery); 543 (34.3%) patients who recovered by week 12 (cluster 2, pain recovery by week 12); 222 (14.0%) patients whose pain reduced but did not recover (cluster 3, incomplete pain recovery); 167 (10.5%) patients whose pain initially decreased but then increased by week 12 (cluster 4, fluctuating pain); and 86 (5.4%) patients who experienced high-level pain for the whole 12 weeks (cluster 5, persistent high pain). Patients with longer pain duration were more likely to experience delayed recovery or nonrecovery. Belief in greater risk of persistence was associated with nonrecovery, but not delayed recovery. Higher pain intensity, longer duration, and workers' compensation were associated with persistent high pain, whereas older age and increased number of episodes were associated with fluctuating pain. Identification of discrete pain trajectory groups offers the potential to better manage acute low back pain.

  19. Bilingualism and Academic Achievement

    ERIC Educational Resources Information Center

    Han, Wen-Jui

    2012-01-01

    Using the Early Childhood Longitudinal Study, Kindergarten Cohort, this study examines the role that bilingualism plays in children's academic developmental trajectories during their early school years, with particular attention on the school environment (N = 16,380). Growth-curve results showed that despite starting with lower math scores in…

  20. Academic Socialization and the Transition to Elementary School: Parents' Conceptions of School Readiness, Practices, and Children's Academic Achievement Trajectories

    ERIC Educational Resources Information Center

    Puccioni, Jaime Lynn

    2012-01-01

    By the time children enter kindergarten, significant socioeconomic and racial gaps in academic achievement exist (Coley, 2002; Rouse, Brooks-Gunn, & Mclanahan, 2005). Kindergarten is considered to be a pivotal point of educational transition, as academic achievement upon kindergarten entry is associated with subsequent academic success…

  1. Reading and math achievement profiles and longitudinal growth trajectories of children with an autism spectrum disorder.

    PubMed

    Wei, Xin; Christiano, Elizabeth R A; Yu, Jennifer W; Wagner, Mary; Spiker, Donna

    2015-02-01

    This study examined the reading and math achievement profiles and longitudinal growth trajectories of a nationally representative sample of children ages 6 through 9 with an autism spectrum disorder. Four distinct achievement profiles were identified: higher-achieving (39%), hyperlexia (9%), hypercalculia (20%) and lower-achieving (32%). Children with hypercalculia and lower-achieving profiles were more likely to be from low socioeconomic families and had lower functional cognitive skills than the higher-achieving profile. All four profiles lost ground in passage comprehension over time. Slower improvement occurred for the higher-achieving group on letter-word identification, the hyperlexia group on conversation abilities and the hypercalculia group on calculation and functional cognitive skills relative to the lower-achieving group.

  2. Levers for Language Growth: Characteristics and Predictors of Language Trajectories between 4 and 7 Years

    PubMed Central

    McKean, Cristina; Eadie, Patricia; Bavin, Edith L.; Bretherton, Lesley; Cini, Eileen

    2015-01-01

    Background Evidence is required as to when and where to focus resources to achieve the greatest gains for children’s language development. Key to these decisions is the understanding of individual differences in children’s language trajectories and the predictors of those differences. To determine optimal timing we must understand if and when children’s relative language abilities become fixed. To determine where to focus effort we must identify mutable factors, that is those with the potential to be changed through interventions, which are associated with significant differences in children’s language scores and rate of progress. Methods Uniquely this study examined individual differences in language growth trajectories in a population sample of children between 4 and 7 years using the multilevel model for change. The influence of predictors, grouped with respect to their mutability and their proximity to the child (least-mutable, mutable-distal, mutable-proximal), were estimated. Results A significant degree of variability in rate of progress between 4 and 7 years was evident, much of which was systematically associated with mutable-proximal factors, that is, those factors with evidence that they are modifiable through interventions with the child or family, such as shared book reading, TV viewing and number of books in the home. Mutable-distal factors, such as family income, family literacy and neighbourhood disadvantage, hypothesised to be modifiable through social policy, were important predictors of language abilities at 4 years. Conclusions Potential levers for language interventions lie in the child’s home learning environment from birth to age 4. However, the role of a family’s material and cultural capital must not be ignored, nor should the potential for growth into the school years. Early Years services should acknowledge the effects of multiple, cascading and cumulative risks and seek to promote child language development through the

  3. Periconception Maternal Folate Status and Human Embryonic Cerebellum Growth Trajectories: The Rotterdam Predict Study

    PubMed Central

    Koning, Irene V.; Groenenberg, Irene A. L.; Gotink, Anniek W.; Willemsen, Sten P.; Gijtenbeek, Manon; Dudink, Jeroen; Go, Attie T. J. I.; Reiss, Irwin K. M.; Steegers, Eric A. P.; Steegers-Theunissen, Régine P. M.

    2015-01-01

    We aimed to investigate whether periconceptional maternal folate status affects human embryonic cerebellar size and growth trajectories. In a prospective periconceptional cohort participants filled out questionnaires and received weekly transvaginal 3D-ultrasounds between 7+0 and 12+6 weeks gestational age (GA). Viable non-malformed singleton pregnancies were selected for cerebellar measurements; transcerebellar diameter, (TCD), left and right cerebellar diameters (LCD, RCD). Linear mixed models were performed to estimate associations between questionnaire data on the timing of maternal folic acid supplement initiation and longitudinal cerebellar measurements as a function of crown-rump length (CRL) and GA. Maternal red blood cell folate concentrations were analysed before 8 weeks GA to validate the associations. A total of 263 serial high quality three-dimensional ultrasound scans of 135 pregnancies were studied. Preconceptional compared to postconceptional initiation of folic acid use was associated with slightly larger cerebellar diameters per millimetre increase of CRL (TCD: β = 0.260mm, 95%CI = 0.023–0.491, p<0.05; LCD: β = 0.171mm, 95%CI = 0.038–0.305, p<0.05; RCD: β = 0.156mm, 95%CI = 0.032–0.280, p<0.05) and with proportional cerebellar growth (TCD/CRL:β = 0.015mm/mm, 95%CI = 0.005–0.024, p<0.01; LCD/CRL:β = 0.012mm/mm, 95%CI = 0.005–0.018, p<0.01; RCD/CRL:β = 0.011mm/mm, 95%CI = 0.005–0.017, p<0.01). Cerebellar growth was significantly highest in the third quartile of maternal red blood cell folate levels (1538–1813 nmol/L). These first findings show that periconceptional maternal folate status is associated with human embryonic cerebellar development. Implications of these small but significant variations for fetal cerebellar growth trajectories and the child’s neurodevelopmental outcome are yet unknown and warrant further investigation. PMID:26491876

  4. Functional mapping of quantitative trait loci underlying growth trajectories using a transform-both-sides logistic model.

    PubMed

    Wu, Rongling; Ma, Chang-Xing; Lin, Min; Wang, Zuoheng; Casella, George

    2004-09-01

    The incorporation of developmental control mechanisms of growth has proven to be a powerful tool in mapping quantitative trait loci (QTL) underlying growth trajectories. A theoretical framework for implementing a QTL mapping strategy with growth laws has been established. This framework can be generalized to an arbitrary number of time points, where growth is measured, and becomes computationally more tractable, when the assumption of variance stationarity is made. In practice, however, this assumption is likely to be violated for age-specific growth traits due to a scale effect. In this article, we present a new statistical model for mapping growth QTL, which also addresses the problem of variance stationarity, by using a transform-both-sides (TBS) model advocated by Carroll and Ruppert (1984, Journal of the American Statistical Association 79, 321-328). The TBS-based model for mapping growth QTL cannot only maintain the original biological properties of a growth model, but also can increase the accuracy and precision of parameter estimation and the power to detect a QTL responsible for growth differentiation. Using the TBS-based model, we successfully map a QTL governing growth trajectories to a linkage group in an example of forest trees. The statistical and biological properties of the estimates of this growth QTL position and effect are investigated using Monte Carlo simulation studies. The implications of our model for understanding the genetic architecture of growth are discussed.

  5. Child Weight Growth Trajectory and its Determinants in a Sample of Iranian Children from Birth until 2 Years of Age

    PubMed Central

    Hosseini, Sayed-Mohsen; Maracy, Mohamad-Reza; Sarrafzade, Sheida; Kelishadi, Roya

    2014-01-01

    Background: Growth is one of the most important indices in child health. The best and most effective way to investigate child health is measuring the physical growth indices such as weight, height and head circumference. Among these measures, weight growth is the simplest and the most effective way to determine child growth status. Weight trend at a given age is the result of cumulative growth experience, whereas growth velocity represents what is happening at the time. Methods: This longitudinal study was conducted among 606 children repeatedly measured from birth until 2 years of age. We used linear mixed model to analyze repeated measures and to determine factors affecting the growth trajectory. LOWESS smooth curve was used to draw velocity curves. Results: Gender, child rank, birth status and feeding mode had a significant effect on weight trajectory. Boys had higher weight during the study. Infants with exclusive breast feeding had higher weight than other infants. Boys had higher growth velocity up to age 6 month. Breast fed infants had higher growth velocity up to 6 month, but thereafter the velocity was higher in other infants. Conclusions: Many of the studies have investigated child growth, but most of them used cross-sectional design. In this study, we used longitudinal method to determine effective factors on weight trend in children from birth until 2-year-old. The effects of perinatal factors on further growth should be considered for prevention of growth disorders and their late complications. PMID:24829720

  6. American Sign Language/English bilingual model: a longitudinal study of academic growth.

    PubMed

    Lange, Cheryl M; Lane-Outlaw, Susan; Lange, William E; Sherwood, Dyan L

    2013-10-01

    This study examines reading and mathematics academic growth of deaf and hard-of-hearing students instructed through an American Sign Language (ASL)/English bilingual model. The study participants were exposed to the model for a minimum of 4 years. The study participants' academic growth rates were measured using the Northwest Evaluation Association's Measure of Academic Progress assessment and compared with a national-normed group of grade-level peers that consisted primarily of hearing students. The study also compared academic growth for participants by various characteristics such as gender, parents' hearing status, and secondary disability status and examined the academic outcomes for students after a minimum of 4 years of instruction in an ASL/English bilingual model. The findings support the efficacy of the ASL/English bilingual model.

  7. Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss) The cost and scarcity of key ingredients for aquaculture feed formulation call for a wise use of resources, especially dietary proteins and energy. For years t...

  8. General Growth Mixture Analysis of Adolescents' Developmental Trajectories of Anxiety: The Impact of Untested Invariance Assumptions on Substantive Interpretations

    ERIC Educational Resources Information Center

    Morin, Alexandre J. S.; Maiano, Christophe; Nagengast, Benjamin; Marsh, Herbert W.; Morizot, Julien; Janosz, Michel

    2011-01-01

    Substantively, this study investigates potential heterogeneity in the developmental trajectories of anxiety in adolescence. Methodologically, this study demonstrates the usefulness of general growth mixture analysis (GGMA) in addressing these issues and illustrates the impact of untested invariance assumptions on substantive interpretations. This…

  9. Trajectories of Heroin Addiction: Growth Mixture Modeling Results Based on a 33-Year Follow-Up Study

    ERIC Educational Resources Information Center

    Hser, Yih-Ing; Huang, David; Chou, Chih-Ping; Anglin, M. Douglas

    2007-01-01

    This study investigates trajectories of heroin use and subsequent consequences in a sample of 471 male heroin addicts who were admitted to the California Civil Addict Program in 1964-1965 and followed over 33 years. Applying a two-part growth mixture modeling strategy to heroin use level during the first 16 years of the addiction careers since…

  10. Stability and Instability in Academic Growth--A Compilation of Longitudinal Data. Final Report.

    ERIC Educational Resources Information Center

    Hilton, Thomas L.; And Others

    This volume constitutes the final report of Phase I of the Analysis of Student Growth and Its Implications for Educational Policy, an investigation undertaken at the Educational Testing Service (ETS). The investigation was based on data from the Growth Study, a nationwide longitudinal study of academic growth. This first phase has been referred to…

  11. The introduction of trajectory oscillations to reduce emittance growth in the SLC linac

    SciTech Connect

    Seeman, J.T.; Decker, F.J. ); Hsu, I. . Inst. of Nuclear Science)

    1992-08-01

    Emittance growth of accelerated beams in the 50 GeV linear accelerator of the Stanford Linear Collider (SLC) arises from the effects of transverse wakefields and momentum dispersion. These effects are caused by small misalignments of the beam position monitors, lattice quadrupoles, and accelerating structure and by the energy spectrum of the beam which changes along the accelerator. The introduction of strategically placed trajectory oscillations over finite lengths of the linac has been used to generate beam errors which cancel the emittance accumulation from these small unknown, random alignment errors. Induced oscillations early in the linac cancel effects which filament along the accelerator affecting mostly the beam core. Induced oscillations located at the center of the accelerator or beyond cancel wakefield and dispersion errors which do not completely filament but cause the beams to have, in addition, an apparent betatron mismatch and transverse tails. The required induced oscillations of a few hundred microns are reasonably stable over a period of several weeks. Of course, the optimum induced oscillations depend upon the beam charge. Emittance reductions of 30 to 50% have been obtained.

  12. Supporting the students most in need: academic self-efficacy and perceived teacher support in relation to within-year academic growth.

    PubMed

    Mercer, Sterett H; Nellis, Leah M; Martínez, Rebecca S; Kirk, Megan

    2011-06-01

    Academic self-efficacy and perceived teacher support in relation to academic skill growth across one academic year were examined in the study. Participants included 193 5th-grade students. Teachers collected curriculum-based measures (CBM) of reading and math on three occasions as part of routine academic benchmarks, and researchers collected student-reported measures of academic self-efficacy and perceived teacher support in the spring of the same academic year. Results indicated that academic self-efficacy was positively related to fall reading and math CBM scores and that perceived teacher support was unrelated to fall scores or growth across the academic year. Academic self-efficacy and perceived teacher support interacted in relation to math CBM growth such that low levels of perceived teacher support were related to greater growth, particularly for students with high academic self-efficacy. Follow-up analyses indicated that students with the lowest fall CBM scores and smallest growth rates reported higher levels of perceived teacher support, suggesting that teachers support the students most in need.

  13. Growth trajectories of the human fetal brain tissues estimated from 3D reconstructed in utero MRI

    PubMed Central

    Scott, Julia A.; Habas, Piotr A.; Kim, Kio; Rajagopalan, Vidya; Hamzelou, Kia S.; Corbett-Detig, James M.; Barkovich, A. James; Glenn, Orit A.; Studholme, Colin

    2012-01-01

    In the latter half of gestation (20 to 40 gestational weeks), human brain growth accelerates in conjunction with cortical folding and the deceleration of ventricular zone progenitor cell proliferation. These processes are reflected in changes in the volume of respective fetal tissue zones. Thus far, growth trajectories of the fetal tissue zones have been extracted primarily from 2D measurements on histological sections and magnetic resonance imaging (MRI). In this study, the volumes of major fetal zones—cortical plate (CP), subplate and intermediate zone (SP+IZ), germinal matrix (GMAT), deep gray nuclei (DG), and ventricles (VENT)—are calculated from automatic segmentation of motion-corrected, 3D reconstructed MRI. We analyzed 48 T2-weighted MRI scans from 39 normally developing fetuses in utero between 20.57 and 31.14 gestational weeks (GW). The supratentorial volume (STV) increased linearly at a rate of 15.22% per week. The SP+IZ (14.75% per week) and DG (15.56% per week) volumes increased at similar rates. The CP increased at a greater relative rate (18.00% per week), while the VENT (9.18% per week) changed more slowly. Therefore, CP increased as a fraction of STV and the VENT fraction declined. The total GMAT volume slightly increased then decreased after 25 GW. We did not detect volumetric sexual dimorphisms or total hemispheric volume asymmetries, which may emerge later in gestation. Further application of the automated fetal brain segmentation to later gestational ages will bridge the gap between volumetric studies of premature brain development and normal brain development in utero. PMID:21530634

  14. Growth trajectories of the human fetal brain tissues estimated from 3D reconstructed in utero MRI.

    PubMed

    Scott, Julia A; Habas, Piotr A; Kim, Kio; Rajagopalan, Vidya; Hamzelou, Kia S; Corbett-Detig, James M; Barkovich, A James; Glenn, Orit A; Studholme, Colin

    2011-08-01

    In the latter half of gestation (20-40 gestational weeks), human brain growth accelerates in conjunction with cortical folding and the deceleration of ventricular zone progenitor cell proliferation. These processes are reflected in changes in the volume of respective fetal tissue zones. Thus far, growth trajectories of the fetal tissue zones have been extracted primarily from 2D measurements on histological sections and magnetic resonance imaging (MRI). In this study, the volumes of major fetal zones-cortical plate (CP), subplate and intermediate zone (SP+IZ), germinal matrix (GMAT), deep gray nuclei (DG), and ventricles (VENT)--are calculated from automatic segmentation of motion-corrected, 3D reconstructed MRI. We analyzed 48 T2-weighted MRI scans from 39 normally developing fetuses in utero between 20.57 and 31.14 gestational weeks (GW). The supratentorial volume (STV) increased linearly at a rate of 15.22% per week. The SP+IZ (14.75% per week) and DG (15.56% per week) volumes increased at similar rates. The CP increased at a greater relative rate (18.00% per week), while the VENT (9.18% per week) changed more slowly. Therefore, CP increased as a fraction of STV and the VENT fraction declined. The total GMAT volume slightly increased then decreased after 25 GW. We did not detect volumetric sexual dimorphisms or total hemispheric volume asymmetries, which may emerge later in gestation. Further application of the automated fetal brain segmentation to later gestational ages will bridge the gap between volumetric studies of premature brain development and normal brain development in utero.

  15. Expressing Academic Growth on a Conjoint Developmental Scale with General Objectivity

    NASA Astrophysics Data System (ADS)

    Williamson, G. L.

    2016-11-01

    Individual growth curves yield insights about growth that are not available from any other methodology; and, developmental scales based on conjoint measurement models provide unique interpretive advantages for investigations of academic growth. Benefits are demonstrated in three examples. First, a series of fifteen statewide reading growth curves is annotated with historical policy actions related to assessment, accountability and early interventions. Second, a common measurement framework simultaneously addresses five interpretive perspectives—student reading growth; achievement level standards; K-12 text complexity standards; postsecondary reading demands; and, occupational reading demands. Third, incremental velocity norms are introduced for average reading growth based on a parametric mathematical model for individual growth curves.

  16. Longitudinal Academic Achievement Outcomes: Modeling the Growth Trajectories of Montessori Elementary Public School Students

    ERIC Educational Resources Information Center

    Mallett, Jan Davis

    2014-01-01

    Elementary education has theoretical underpinnings based on cognitive psychology. Ideas from cognitive psychologists such as James, Dewey, Piaget, and Vygotsky coalesce to form constructivism (Cooper, 1993; Yager, 2000; Yilmaz, 2011). Among others, the Montessori Method (1912/1964) is an exemplar of constructivism. Currently, public education in…

  17. Measuring the Impact of Substance Abuse on Student Academic Achievement and Academic Growth

    ERIC Educational Resources Information Center

    Rattermann, Mary Jo

    2014-01-01

    This research presents data linking the impact of substance disorder to academic achievement, using data gathered at a recovery high school. Recovery schools provide recovery supports and a high-quality education to students with substance use disorders. The Global Appraisal of Individual Needs -- Short Screener and the Northwest Evaluation…

  18. Academic Growth: Strategies To Improve Student Engagement in Their Learning.

    ERIC Educational Resources Information Center

    Naffziger, Sue C.; Steele, Martha M.; Varner, Bruce O.

    This action research project evaluated a program of activities to increase the engagement of high school students in their learning. The targeted population consisted of freshman, sophomore, and senior students in a middle class community in central Illinois. The lack of student engagement that posed a problem in academic progress was documented…

  19. Evaluating Longitudinal Mathematics Achievement Growth: Modeling and Measurement Considerations for Assessing Academic Progress

    ERIC Educational Resources Information Center

    Shanley, Lina

    2016-01-01

    Accurately measuring and modeling academic achievement growth is critical to support educational policy and practice. Using a nationally representative longitudinal data set, this study compared various models of mathematics achievement growth on the basis of both practical utility and optimal statistical fit and explored relationships within and…

  20. Attaining the canopy in dry and moist tropical forests: strong differences in tree growth trajectories reflect variation in growing conditions

    PubMed Central

    Zuidema, Pieter A.; Martínez-Ramos, Miguel

    2009-01-01

    Availability of light and water differs between tropical moist and dry forests, with typically higher understorey light levels and lower water availability in the latter. Therefore, growth trajectories of juvenile trees—those that have not attained the canopy—are likely governed by temporal fluctuations in light availability in moist forests (suppressions and releases), and by spatial heterogeneity in water availability in dry forests. In this study, we compared juvenile growth trajectories of Cedrela odorata in a dry (Mexico) and a moist forest (Bolivia) using tree rings. We tested the following specific hypotheses: (1) moist forest juveniles show more and longer suppressions, and more and stronger releases; (2) moist forest juveniles exhibit wider variation in canopy accession pattern, i.e. the typical growth trajectory to the canopy; (3) growth variation among dry forest juveniles persists over longer time due to spatial heterogeneity in water availability. As expected, the proportion of suppressed juveniles was higher in moist than in dry forest (72 vs. 17%). Moist forest suppressions also lasted longer (9 vs. 5 years). The proportion of juveniles that experienced releases in moist forest (76%) was higher than in dry forest (41%), and releases in moist forests were much stronger. Trees in the moist forest also had a wider variation in canopy accession patterns compared to the dry forest. Our results also showed that growth variation among juvenile trees persisted over substantially longer periods of time in dry forest (>64 years) compared to moist forest (12 years), most probably because of larger persistent spatial variation in water availability. Our results suggest that periodic increases in light availability are more important for attaining the canopy in moist forests, and that spatial heterogeneity in water availability governs long-term tree growth in dry forests. Electronic supplementary material The online version of this article (doi:10.1007/s

  1. Growth Trajectories of Early Aggression, Overactivity, and Inattention: Relations to Second-Grade Reading

    ERIC Educational Resources Information Center

    Gray, Sarah A. O.; Carter, Alice S.; Briggs-Gowan, Margaret J.; Jones, Stephanie M.; Wagmiller, Robert L.

    2014-01-01

    The link between behavior problems and low academic achievement is well established, but few studies have examined longitudinal relations between early externalizing behaviors before school entry and low academic achievement following transition to formal schooling. Early inattention has been particularly overlooked, despite strong associations…

  2. The Growth of English for Academic Communication in the Nordic Countries

    NASA Astrophysics Data System (ADS)

    Brock-Utne, Birgit

    2001-07-01

    This article discusses the danger of subtractive English in higher education in Norway. If the use of a mother tongue as the medium of communication at the highest academic levels ceases, is drastically reduced and replaced through the use of a foreign tongue, we may speak of subtractive learning. If the mother tongue is being replaced by a foreign tongue in academic writing, in research and university level teaching, the mother tongue will stagnate. The vocabulary needed has not been allowed to develop at the highest academic level. The author maintains that the Norwegian language is threatened as an academic language and here discusses the following five phenomena, all contributing to this threat: 1. The increasing use of English words in Norwegian academic, bureaucratic or technological language. 2. The sale of more academic literature in English and stagnation of academic literature in Norwegian. 3. The recruitment of teaching staff who do not speak Norwegian. 4. The growth in Master degree courses taught in English. 5. The financial rewards being given to academic staff publishing in an international language (read: English) instead of in the mother tongue.

  3. Trajectories of Change and Relationship between Parent-Adolescent School-Related Conflict and Academic Achievement in Early Adolescence

    ERIC Educational Resources Information Center

    Brkovic, Irma; Keresteš, Gordana; Puklek Levpušc?ek, Melita

    2014-01-01

    The study explored changes in parent-adolescent school-related conflict rate and academic performance over a 5-year period among Croatian early adolescents and gender differences in these changes. Furthermore, it examined the relationship between conflict and achievement. The study was performed by applying an accelerated approach to overlapping…

  4. Neither Colorblind nor Oppositional: Perceived Minority Status and Trajectories of Academic Adjustment among Latinos in Elite Higher Education

    ERIC Educational Resources Information Center

    Rivas-Drake, Deborah; Mooney, Margarita

    2009-01-01

    As more Latinos experience upward social mobility, it is increasingly necessary to challenge oppositional cultural assumptions to explain how perceived minority status barriers may influence their academic achievement. The present study builds on previous work that identified 3 distinct minority status orientations among Latino college students…

  5. Academic Achievement Trajectories of Homeless and Highly Mobile Students: Resilience in the Context of Chronic and Acute Risk

    ERIC Educational Resources Information Center

    Cutuli, J. J.; Desjardins, Christopher David; Herbers, Janette E.; Long, Jeffrey D.; Heistad, David; Chan, Chi-Keung; Hinz, Elizabeth; Masten, Ann S.

    2013-01-01

    Analyses examined academic achievement data across third through eighth grades ("N" = 26,474), comparing students identified as homeless or highly mobile (HHM) with other students in the federal free meal program (FM), reduced price meals (RM), or neither (General). Achievement was lower as a function of rising risk status (General…

  6. Growth trajectories from conception through middle childhood and cognitive achievement at age 8 years: Evidence from four low- and middle-income countries.

    PubMed

    Georgiadis, Andreas; Benny, Liza; Crookston, Benjamin T; Duc, Le Thuc; Hermida, Priscila; Mani, Subha; Woldehanna, Tassew; Stein, Aryeh D; Behrman, Jere R

    2016-12-01

    Child chronic malnutrition is endemic in low- and middle-income countries and deleterious for child development. Studies investigating the relationship between nutrition at different periods of childhood, as measured by growth in these periods (growth trajectories), and cognitive development have produced mixed evidence. Although an explanation of this has been that different studies use different approaches to model growth trajectories, the differences across approaches are not well understood. Furthermore, little is known about the pathways linking growth trajectories and cognitive achievement. In this paper, we develop and estimate a general path model of the relationship between growth trajectories and cognitive achievement using data on four cohorts from Ethiopia, India, Peru, and Vietnam. The model is used to: a) compare two of the most common approaches of modelling growth trajectories in the literature, namely the lifecourse plot and the conditional body size model, and b) investigate the potential channels via which the association between growth in each period and cognitive achievement manifests. We show that the two approaches are expected to produce systematically different results that have distinct interpretations. Results suggest that growth from conception through age 1 year, between age 1 and 5 years, and between 5 and 8 years are each positively and significantly associated with cognitive achievement at age 8 years and that this may be partly explained by the fact that faster-growing children start school earlier. We also find that a significant share of the association between early growth and later cognitive achievement is mediated through growth in interim periods.

  7. Does academic performance or personal growth share a stronger association with learning environment perception?

    PubMed Central

    Tackett, Sean; Wright, Scott M.; Shochet, Robert S.

    2016-01-01

    Objectives This study was conducted to characterize the relative strength of associations of learning environment perception with academic performance and with personal growth. Methods In 2012-2014 second and third year students at Johns Hopkins University School of Medicine completed a learning environment survey and personal growth scale. Hierarchical linear regression analysis was employed to determine if the proportion of variance in learning environment scores accounted for by personal growth was significantly larger than the proportion accounted for by academic performance (course/clerkship grades). Results The proportion of variance in learning environment scores accounted for by personal growth was larger than the proportion accounted for by academic performance in year 2 [R2Δ of 0.09, F(1,175) = 14.99,  p < .001] and year 3 [R2Δ of 0.28, F(1,169) = 76.80, p < .001]. Learning environment scores shared a small amount of variance with academic performance in years 2 and 3.  The amount of variance between learning environment scores and personal growth was small in year 2 and large in year 3. Conclusions Since supportive learning environments are essential for medical education, future work must determine if enhancing personal growth prior to and during the clerkship year will increase learning environment perception. PMID:27570912

  8. Trajectory Pathways for Depressive Symptoms and Their Associated Factors in a Chinese Primary Care Cohort by Growth Mixture Modelling

    PubMed Central

    2016-01-01

    Background The naturalistic course for patients suffering from depressive disorders can be quite varied. Whilst some remit with little or no intervention, others may suffer a more prolonged course of symptoms. The aim of this study was to identify trajectory patterns for depressive symptoms in a Chinese primary care cohort and their associated factors. Methods and Results A 12-month cohort study was conducted. Patients recruited from 59 primary care clinics across Hong Kong were screened for depressive symptoms using the Centre for Epidemiologic Studies Depression Scale (CES-D) and monitored over 12 months using the Patient Health Questionnaire-9 items (PHQ-9) administered at 12, 26 and 52 weeks. 721 subjects were included for growth mixture modelling analysis. Using Akaike Information Criterion, Bayesian Information Criterion, Entropy and Lo-Mendell-Rubin adjusted likelihood ratio test, a seven-class trajectory path model was identified. Over 12 months, three trajectory groups showed improvement in depressive symptoms, three remained static, whilst one deteriorated. A mild severity of depressive symptoms with gradual improvement was the most prevalent trajectory identified. Multivariate, multinomial regression analysis was used to identify factors associated with each trajectory. Risk factors associated with chronicity included: female gender; not married; not in active employment; presence of multiple chronic disease co-morbidities; poor self-rated general health; and infrequent health service use. Conclusions Whilst many primary care patients may initially present with a similar severity of depressive symptoms, their course over 12 months can be quite heterogeneous. Although most primary care patients improve naturalistically over 12 months, many do not remit and it is important for doctors to be able to identify those who are at risk of chronicity. Regular follow-up and greater treatment attention is recommended for patients at risk of chronicity. PMID:26829330

  9. Webinar Presentation: Exposures to Polycyclic Aromatic Hydrocarbons and Childhood Growth Trajectories and Body Composition: Linkages to Disrupted Self-Regulatory Processes

    EPA Pesticide Factsheets

    This presentation, Exposures to Polycyclic Aromatic Hydrocarbons and Childhood Growth Trajectories and Body Composition: Linkages to Disrupted Self-Regulatory Processes, was given at the NIEHS/EPA Children's Centers 2016 Webinar Series: Childhood Obesity

  10. Organizational development trajectory of a large academic radiotherapy department set up similarly to a prospective clinical trial: the MAASTRO experience

    PubMed Central

    Boersma, L; Dekker, A; Hermanns, E; Houben, R; Govers, M; van Merode, F; Lambin, P

    2015-01-01

    Objective: To simultaneously improve patient care processes and clinical research activities by starting a hypothesis-driven reorganization trajectory mimicking the rigorous methodology of a prospective clinical trial. Methods: The design of this reorganization trajectory was based on the model of a prospective trial. It consisted of (1) listing problems and analysing their potential causes, (2) defining interventions, (3) defining end points and (4) measuring the effect of the interventions (i.e. at baseline and after 1 and 2 years). The primary end point for patient care was the number of organizational root causes of incidents/near incidents; for clinical research, it was the number of patients in trials. There were several secondary end points. We analysed the data using two sample z-tests, χ2 test, a Mann–Whitney U test and the one-way analysis of variance with Bonferroni correction. Results: The number of organizational root causes was reduced by 27% (p < 0.001). There was no effect on the percentage of patients included in trials. Conclusion: The reorganizational trajectory was successful for the primary end point of patient care and had no effect on clinical research. Some confounding events hampered our ability to draw strong conclusions. Nevertheless, the transparency of this approach can give medical professionals more confidence in moving forward with other organizational changes in the same way. Advances in knowledge: This article is novel because managerial interventions were set up similarly to a prospective clinical trial. This study is the first of its kind in radiotherapy, and this approach can contribute to discussions about the effectiveness of managerial interventions. PMID:25679320

  11. Functional Mapping of Quantitative Trait Loci That Interact With the hg Mutation to Regulate Growth Trajectories in Mice

    PubMed Central

    Wu, Rongling; Ma, Chang-Xing; Hou, Wei; Corva, Pablo; Medrano, Juan F.

    2005-01-01

    The high growth (hg) mutation increases body size in mice by 30–50%. Given the complexity of the genetic regulation of animal growth, it is likely that the effect of this major locus is mediated by other quantitative trait loci (QTL) with smaller effects within a web of gene interactions. In this article, we extend our functional mapping model to characterize modifier QTL that interact with the hg locus during ontogenetic growth. Our model is derived within the maximum-likelihood context, incorporated by mathematical aspects of growth laws and implemented with the EM algorithm. In an F2 population founded by a congenic high growth (HG) line and non-HG line, a highly additive effect due to the hg gene was detected on growth trajectories. Three QTL located on chromosomes 2 and X were identified to trigger significant additive and/or dominant effects on the process of growth. The most significant finding made from our model is that these QTL interact with the hg locus to affect the shapes of the growth process. Our model provides a powerful means for understanding the genetic architecture and regulation of growth rate and body size in mammals. PMID:15965258

  12. Family Background, School-Age Trajectories of Activity Participation, and Academic Achievement at the Start of High School

    PubMed Central

    Crosnoe, Robert; Smith, Chelsea; Leventhal, Tama

    2014-01-01

    Applying latent class and regression techniques to data from the NICHD Study of Early Child Care and Youth Development (n = 997), this study explored the potential academic advantages of time spent in out-of-school activities. Of particular interest was how these potential advantages played out in relation to the timing and duration of activity participation and the family contexts in which it occurred. Participation closer to the start of high school—including consistent participants and latecomers—was associated with higher grades at the transition into high school, especially for youth from low-income families. Sensitivity analyses indicated that this link between school-age activity participation and adolescent academic progress was unlikely to be solely a function of selection. It also tended to be more pronounced among youth from lower-income families, although without varying by other aspects of family status or process. PMID:26279615

  13. Factors Affecting the Adequacy and Preferability of Semiparametric Groups-Based Approximations of Continuous Growth Trajectories

    ERIC Educational Resources Information Center

    Sterba, Sonya K.; Baldasaro, Ruth E.; Bauer, Daniel J.

    2012-01-01

    Psychologists have long been interested in characterizing individual differences in change over time. It is often plausible to assume that the distribution of these individual differences is continuous in nature, yet theory is seldom so specific as to designate its parametric form (e.g., normal). Semiparametric groups-based trajectory models…

  14. Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

    PubMed Central

    McClelland, Megan M.; Cameron, Claire E.; Duncan, Robert; Bowles, Ryan P.; Acock, Alan C.; Miao, Alicia; Pratt, Megan E.

    2014-01-01

    Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics. PMID:25071619

  15. Stunted at 10 Years. Linear Growth Trajectories and Stunting from Birth to Pre-Adolescence in a Rural Bangladeshi Cohort

    PubMed Central

    Svefors, Pernilla; Rahman, Anisur; Ekström, Eva-Charlotte; Khan, Ashraful Islam; Lindström, Emma; Persson, Lars Åke; Ekholm Selling, Katarina

    2016-01-01

    Background Few studies in low-income settings analyse linear growth trajectories from foetal life to pre-adolescence. The aim of this study is to describe linear growth and stunting from birth to 10 years in rural Bangladesh and to analyse whether maternal and environmental determinants at conception are associated with linear growth throughout childhood and stunting at 10 years. Methods and Findings Pregnant women participating in the MINIMat trial were identified in early pregnancy and a birth cohort (n = 1054) was followed with 19 growth measurements from birth to 10 years. Analyses of baseline predictors and mean height-for-age Z-scores (HAZ) over time were modelled using GLMM. Logistic regression analysis was used to investigate the associations between baseline predictors and stunting (HAZ<-2) at 10 years. HAZ decreased to 2 years, followed by an increase up to 10 years, while the average height-for-age difference in cm (HAD) to the WHO reference median continued to increase up to 10 years. Prevalence of stunting was highest at 2 years (50%) decreasing to 29% at 10 years. Maternal height, maternal educational level and season of conception were all independent predictors of HAZ from birth to pre-adolescence (p<0.001) and stunting at 10 years. The highest probability to be stunted at 10 years was for children born by short mothers (<147.5 cm) (ORadj 2.93, 95% CI: 2.06–4.20), mothers with no education (ORadj 1.74, 95% CI 1.17–2.81) or those conceived in the pre-monsoon season (ORadj 1.94, 95% CI 1.37–2.77). Conclusions Height growth trajectories and prevalence of stunting in pre-adolescence showed strong intergenerational associations, social differentials, and environmental influence from foetal life. Targeting women before and during pregnancy is needed for the prevention of impaired child growth. PMID:26934484

  16. Enhancing Student Motivation as Evidenced by Improved Academic Growth and Increased Work Completion.

    ERIC Educational Resources Information Center

    Belcher, Gay; Macari, Nancy

    This project evaluated a program for enhancing student motivation as evidenced by improved academic growth and increased work completion. The targeted population consisted of fifth graders in a small school in a medium-sized rural community in the Midwest. The problem of lack of achievement motivation and lack of student concern about academic…

  17. The Impact of Course Rigor and Course-Taking Patterns on High School Student Academic Growth: A Quantitative Analysis

    ERIC Educational Resources Information Center

    Newkirk, Brad

    2013-01-01

    Because of national, state, and local accountability to prepare students to be college and career-ready, secondary schools are looking for ways to maximize student academic growth while in high school. The purpose of this study was to investigate the relation between academic growth as measured by the changes in performance from students' 8th…

  18. Identifying Latent Trajectories of Personality Disorder Symptom Change: Growth Mixture Modeling in the Longitudinal Study of Personality Disorders

    PubMed Central

    Hallquist, Michael N.; Lenzenweger, Mark F.

    2013-01-01

    Although previous reports have documented mean-level declines in personality disorder (PD) symptoms over time, little is known about whether personality pathology sometimes emerges among nonsymptomatic adults, or whether rates of change differ qualitatively among symptomatic persons. Our study sought to characterize heterogeneity in the longitudinal course of PD symptoms with the goal of testing for and describing latent trajectories. Participants were 250 young adults selected into two groups using a PD screening measure: those who met diagnostic criteria for a DSM-III-R PD (PPD, n = 129), and those with few PD symptoms (NoPD, n = 121). PD symptoms were assessed three times over a four-year study using semistructured interviews. Total PD symptom counts and symptoms of each DSM-III-R PD were analyzed using growth mixture modeling. In the NoPD group, latent trajectories were characterized by stable, minor symptoms; the rapid or gradual remission of subclinical symptoms; or the emergence of symptoms of Avoidant, Obsessive-Compulsive, or Paranoid PD. In the PPD group, three latent trajectories were evident: rapid symptom remission, slow symptom decline, or a relative absence of symptoms. Rapid remission of PD symptoms was associated with fewer comorbid disorders, lower negative emotionality, and greater positive emotionality and constraint, whereas emergent personality dysfunction was associated with comorbid PD symptoms and lower positive emotionality. In most cases, symptom change for one PD was associated with concomitant changes in other PDs, depressive symptoms, and anxiety. These results indicate that the longitudinal course of PD symptoms is heterogeneous, with distinct trajectories evident for both symptomatic and nonsymptomatic individuals. The prognosis of PD symptoms may be informed by an assessment of personality and comorbid psychopathology. PMID:23231459

  19. Generating Vocabulary Knowledge for At-Risk Middle School Readers: Contrasting Program Effects and Growth Trajectories

    ERIC Educational Resources Information Center

    Lawrence, Joshua F.; Rolland, Rebecca Givens; Branum-Martin, Lee; Snow, Catherine E.

    2014-01-01

    We tested whether urban middle-school students from mostly low-income homes had improved academic vocabulary when they participated in a freely available vocabulary program, Word Generation (WG). To understand how this program may support students at risk for long-term reading difficulty, we examined treatment interactions with baseline…

  20. Cluster Analysis as a Method of Recovering Types of Intraindividual Growth Trajectories: A Monte Carlo Study.

    ERIC Educational Resources Information Center

    Dumenci, Levent; Windle, Michael

    2001-01-01

    Used Monte Carlo methods to evaluate the adequacy of cluster analysis to recover group membership based on simulated latent growth curve (LCG) models. Cluster analysis failed to recover growth subtypes adequately when the difference between growth curves was shape only. Discusses circumstances under which it was more successful. (SLD)

  1. Implicit Theories about Intelligence and Growth (Personal Best) Goals: Exploring Reciprocal Relationships

    ERIC Educational Resources Information Center

    Martin, Andrew J.

    2015-01-01

    Background: There has been increasing interest in growth approaches to students' academic development, including value-added models, modelling of academic trajectories, growth motivation orientations, growth mindsets, and growth goals. Aims: This study sought to investigate the relationships between implicit theories about intelligence…

  2. The Interactive Role of Socioeconomic Status, Race/Ethnicity, and Birth Weight on Trajectories of Body Mass Index Growth in Children and Adolescents

    ERIC Educational Resources Information Center

    Danner, Fred W.; Toland, Michael D.

    2013-01-01

    This study assessed how socioeconomic status (SES), race/ethnicity, and birth weight interacted to predict differential patterns of body mass index (BMI) growth among U.S. children born in the early 1990s. Three BMI growth trajectories emerged--one above the 50th percentile across the age range of 5 to 14, one in which children rapidly became…

  3. Linear and ponderal growth trajectories in well-nourished, iron-sufficient infants are unimpaired by iron supplementation.

    PubMed

    Gahagan, Sheila; Yu, Sunkyung; Kaciroti, Niko; Castillo, Marcela; Lozoff, Betsy

    2009-11-01

    Iron deficiency remains the most common nutritional deficiency worldwide and supplementation is recommended during periods of high risk, including infancy. However, questions have been raised about possible adverse effects of iron on growth in iron-sufficient (IS) infants and the advisability of across-the-board iron supplementation. This study examined whether short- or long-term growth was impaired in IS infants who received iron supplementation. From a longitudinal study of healthy, breast-fed, low- to middle-income Chilean infants randomly assigned to iron supplementation or usual nutrition at 6 or 12 mo, we retrospectively identified infants meeting criteria for iron sufficiency at the time of random assignment (n = 273). Using multilevel analysis, ponderal and linear growth were modeled before, during, and after iron supplementation up to 10 y in 3 comparisons: 1) iron supplementation compared with usual nutrition from 6 to 12 mo; 2) iron supplementation compared with usual nutrition from 12 to 18 mo; and 3) 15 mg/d of iron as drops compared with iron-fortified formula (12 mg/L). Growth trajectories did not differ during or after supplementation indicating no adverse effect of iron in any comparison. These results suggest that, at least in some environments, iron does not impair growth in IS infants.

  4. Opportunity for academic research in a low-gravity environment - Crystal growth

    NASA Technical Reports Server (NTRS)

    Matthiesen, D. H.; Wargo, M. J.; Witt, A. F.

    1986-01-01

    The history of basic and applied research on crystal growth (CG), especially of semiconductor materials, is reviewed, stressing the dominance (at least in the U.S.) of industrial R&D projects over academic programs and the need for more extensive fundamental investigations. The NASA microgravity research program and the recommendations of the University Space Research Association are examined as they affect the availability of space facilities for academic CG research. Also included is a report on ground experiments on the effectiveness of magnetic fields in controlling vertical Bridgman CG and melt stability, using the apparatus employed in the Apollo-Soyuz experiments (Witt et al., 1978); the results are presented in graphs and briefly characterized. The role of NASA's microgravity CG program in stimulating academic work on CG, the importance of convection effects, CG work on materials other than semiconductors, and NSF support of CG research are discussed in a comment by R. F. Sekerka.

  5. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    PubMed

    Paul, Nicholas A; Svensson, Carl Johan; de Nys, Rocky; Steinberg, Peter D

    2014-01-01

    All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells). To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  6. Heterogeneity in Trajectories of Child Maltreatment Severity: A Two-Part Growth Mixture Model

    PubMed Central

    Yampolskaya, Svetlana; Greenbaum, Paul E.; Brown, C. Hendricks; Armstrong, Mary I.

    2016-01-01

    This study examined the trajectories of maltreatment severity and substantiation over a 24-month period among children (N = 82,396) with repeated maltreatment reports. Findings revealed two different longitudinal patterns. The first pattern, Elevated Severity, showed a higher level of maltreatment during the initial incident and increased maltreatment severity during subsequent incidents but the substantiation rates for this class decreased over time. The second pattern, Lowered Severity, showed a much lower level of severity, but the likelihood of substantiation increased over time. The Elevated Severity class was comprised of children with an elevated risk profile due to both individual and contextual risk factors including older age, female gender, caregivers’ substance use problems, and a higher number of previous maltreatment reports. Implications of the findings are discussed. PMID:26300381

  7. Growth in young Filipino children predicts schooling trajectories through high school.

    PubMed

    Daniels, Melissa C; Adair, Linda S

    2004-06-01

    Several studies link childhood malnutrition to adverse schooling outcomes, including delayed or diminished enrollment and increased grade repetition. However, the effects of nutrition on schooling trajectories are obscured by the cross-sectional nature of most previous research and the complex array of other phenomena that affect schooling outcomes. We explored the association between height-for-age Z-score (HAZ) at 2 y and schooling trajectory among 2198 children from the Cebu Longitudinal Health and Nutrition Survey. Parity, parental education, maternal height, household assets, environmental cleanliness, presence of electricity, and household income were identified as potential confounders. Crude and adjusted logistic and multinomial regressions of schooling outcomes (entrance age, grade repetition, and grades completed) were conducted. Entrance age and IQ were evaluated as potential mediators between HAZ and schooling outcomes. After adjustment for confounders, greater height for age protected against late enrollment among both boys and girls and predicted early enrollment among boys. Taller children were less likely to repeat grades [girls OR = 0.78 (0.67, 0.89); boys OR = 0.86 (0.74, 0.99)] and less likely to drop out during grade school rather than graduate from high school [girls OR = 0.74 (0.56, 0.98; boys OR = 0.66 (0.51, 0.84)]. Models predicting the changes in school outcomes associated with a change in overall height from -2 to 0 SD of HAZ were simulated. Absolute probability of late enrollment dropped substantially, from 6% for both boys and girls to 2% for boys and 1% for girls. Absolute grade repetition dropped approximately 7% for boys and 9% for girls. Improving early childhood nutrition may have long-lasting educational benefits, increasing the likelihood of high school completion in developing countries.

  8. Specification Search for Identifying the Correct Mean Trajectory in Polynomial Latent Growth Models

    ERIC Educational Resources Information Center

    Kim, Minjung; Kwok, Oi-Man; Yoon, Myeongsun; Willson, Victor; Lai, Mark H. C.

    2016-01-01

    This study investigated the optimal strategy for model specification search under the latent growth modeling (LGM) framework, specifically on searching for the correct polynomial mean or average growth model when there is no a priori hypothesized model in the absence of theory. In this simulation study, the effectiveness of different starting…

  9. Linear spline multilevel models for summarising childhood growth trajectories: A guide to their application using examples from five birth cohorts.

    PubMed

    Howe, Laura D; Tilling, Kate; Matijasevich, Alicia; Petherick, Emily S; Santos, Ana Cristina; Fairley, Lesley; Wright, John; Santos, Iná S; Barros, Aluísio Jd; Martin, Richard M; Kramer, Michael S; Bogdanovich, Natalia; Matush, Lidia; Barros, Henrique; Lawlor, Debbie A

    2016-10-01

    Childhood growth is of interest in medical research concerned with determinants and consequences of variation from healthy growth and development. Linear spline multilevel modelling is a useful approach for deriving individual summary measures of growth, which overcomes several data issues (co-linearity of repeat measures, the requirement for all individuals to be measured at the same ages and bias due to missing data). Here, we outline the application of this methodology to model individual trajectories of length/height and weight, drawing on examples from five cohorts from different generations and different geographical regions with varying levels of economic development. We describe the unique features of the data within each cohort that have implications for the application of linear spline multilevel models, for example, differences in the density and inter-individual variation in measurement occasions, and multiple sources of measurement with varying measurement error. After providing example Stata syntax and a suggested workflow for the implementation of linear spline multilevel models, we conclude with a discussion of the advantages and disadvantages of the linear spline approach compared with other growth modelling methods such as fractional polynomials, more complex spline functions and other non-linear models.

  10. Investigating trajectories of social recovery in individuals with first-episode psychosis: a latent class growth analysis

    PubMed Central

    Hodgekins, Jo; Birchwood, Max; Christopher, Rose; Marshall, Max; Coker, Sian; Everard, Linda; Lester, Helen; Jones, Peter; Amos, Tim; Singh, Swaran; Sharma, Vimal; Freemantle, Nick; Fowler, David

    2015-01-01

    Background Social disability is a hallmark of severe mental illness yet individual differences and factors predicting outcome are largely unknown. Aim To explore trajectories and predictors of social recovery following a first episode of psychosis (FEP). Method A sample of 764 individuals with FEP were assessed on entry into early intervention in psychosis (EIP) services and followed up over 12 months. Social recovery profiles were examined using latent class growth analysis. Results Three types of social recovery profile were identified: Low Stable (66%), Moderate-Increasing (27%), and High-Decreasing (7%). Poor social recovery was predicted by male gender, ethnic minority status, younger age at onset of psychosis, increased negative symptoms, and poor premorbid adjustment. Conclusions Social disability is prevalent in FEP, although distinct recovery profiles are evident. Where social disability is present on entry into EIP services it can remain stable, highlighting a need for targeted intervention. PMID:26294371

  11. Preweaning GH Treatment Normalizes Body Growth Trajectory and Reverses Metabolic Dysregulation in Adult Offspring After Maternal Undernutrition.

    PubMed

    Li, Minglan; Reynolds, Clare M; Gray, Clint; Vickers, Mark H

    2015-09-01

    Maternal undernutrition (UN) results in growth disorders and metabolic dysfunction in offspring. Although dysregulation of the GH-IGF axis in offspring is a known consequence of maternal UN, little is known about the efficacy of GH treatment during the period of developmental plasticity on later growth and metabolic outcomes. The present study investigated the effect of preweaning GH treatment on growth, glucose metabolism, and the GH-IGF axis in adult male and female offspring after maternal UN. Female Sprague Dawley rats were fed either a chow diet ad libitum (control [CON]) or 50% of ad libitum (UN) throughout pregnancy. From postnatal day 3, CON and UN pups received either saline (CON-S and UN-S) or GH (2.5 μg/g·d CON-GH and UN-GH) daily throughout lactation. At weaning, male and female offspring were randomly selected from each litter and fed a standard chow diet for the remainder of the study. Preweaning GH treatment normalized maternal UN-induced alterations in postweaning growth trajectory and concomitant adiposity in offspring. Plasma leptin concentrations were increased in UN-S offspring and normalized in the UN-GH group. Hepatic GH receptor expression was significantly elevated in UN-S offspring and normalized with GH treatment. Hepatic IGF binding protein-2 gene expression and plasma IGF-1 to IGF binding protein-3 ratio was reduced in UN-S offspring and elevated with GH treatment. GH treatment during a critical developmental window prevented maternal UN-induced changes in postnatal growth patterns and related adiposity, suggesting that manipulation of the GH-IGF-1 axis in early development may represent a promising avenue to prevent adverse developmental programming effects in adulthood.

  12. Intrauterine Cannabis Exposure Affects Fetal Growth Trajectories: The Generation R Study

    ERIC Educational Resources Information Center

    El Marroun, Hanan; Tiemeier, Henning; Steegers, Eric A. P.; Jaddoe, Vincent W. V.; Hofman, Albert; Verhulst, Frank C.; van den Brink, Wim; Huizink, Anja C.

    2009-01-01

    Objective: Cannabis is the most commonly consumed illicit drug among pregnant women. Intrauterine exposure to cannabis may result in risks for the developing fetus. The importance of intrauterine growth on subsequent psychological and behavioral child development has been demonstrated. This study examined the relation between maternal cannabis use…

  13. Examining the Earnings Trajectories of Community College Students Using a Piecewise Growth Curve Modeling Approach

    ERIC Educational Resources Information Center

    Jaggars, Shanna Smith; Xu, Di

    2016-01-01

    Policymakers have become increasingly concerned with measuring--and holding colleges accountable for--students' labor market outcomes. In this article we introduce a piecewise growth curve approach to analyzing community college students' labor market outcomes, and we discuss how this approach differs from two popular econometric approaches:…

  14. Childhood Body Mass Index in Community Context: Neighborhood Safety, Television Viewing, and Growth Trajectories of BMI

    ERIC Educational Resources Information Center

    Cecil-Karb, Rebecca; Grogan-Kaylor, Andrew

    2009-01-01

    The United States is currently experiencing an epidemic of children who are overweight or obese. Recently, research on child obesity has begun to examine the relationship between neighborhood environments and the health behaviors of youths. The current study used growth curve analysis based on multilevel modeling to examine the relationship…

  15. Identifying Longitudinal Growth Trajectories of Learning Domains in Problem-Based Learning: A Latent Growth Curve Modeling Approach Using SEM

    ERIC Educational Resources Information Center

    Wimmers, Paul F.; Lee, Ming

    2015-01-01

    To determine the direction and extent to which medical student scores (as observed by small-group tutors) on four problem-based-learning-related domains change over nine consecutive blocks during a two-year period (Domains: Problem Solving/Use of Information/Group Process/Professionalism). Latent growth curve modeling is used to analyze…

  16. Water resources management in a homogenizing world: Averting the Growth and Underinvestment trajectory

    NASA Astrophysics Data System (ADS)

    Mirchi, Ali; Watkins, David W.; Huckins, Casey J.; Madani, Kaveh; Hjorth, Peder

    2014-09-01

    Biotic homogenization, a de facto symptom of a global biodiversity crisis, underscores the urgency of reforming water resources management to focus on the health and viability of ecosystems. Global population and economic growth, coupled with inadequate investment in maintenance of ecological systems, threaten to degrade environmental integrity and ecosystem services that support the global socioeconomic system, indicative of a system governed by the Growth and Underinvestment (G&U) archetype. Water resources management is linked to biotic homogenization and degradation of system integrity through alteration of water systems, ecosystem dynamics, and composition of the biota. Consistent with the G&U archetype, water resources planning primarily treats ecological considerations as exogenous constraints rather than integral, dynamic, and responsive parts of the system. It is essential that the ecological considerations be made objectives of water resources development plans to facilitate the analysis of feedbacks and potential trade-offs between socioeconomic gains and ecological losses. We call for expediting a shift to ecosystem-based management of water resources, which requires a better understanding of the dynamics and links between water resources management actions, ecological side-effects, and associated long-term ramifications for sustainability. To address existing knowledge gaps, models that include dynamics and estimated thresholds for regime shifts or ecosystem degradation need to be developed. Policy levers for implementation of ecosystem-based water resources management include shifting away from growth-oriented supply management, better demand management, increased public awareness, and institutional reform that promotes adaptive and transdisciplinary management approaches.

  17. Changing brains: how longitudinal functional magnetic resonance imaging studies can inform us about cognitive and social-affective growth trajectories.

    PubMed

    Crone, Eveline A; Elzinga, Bernet M

    2015-01-01

    Brain imaging studies have demonstrated widespread changes in brain networks which support cognitive and social-affective development. These conclusions, however, are largely based on cross-sectional comparisons, which limits the possibility to investigate growth trajectories and detect individual changes. Understanding individual growth patterns is crucial if we want to ultimately understand how brain development is sensitive to environmental influences such as educational or psychological interventions or childhood maltreatment. Recently, longitudinal brain imaging studies in children and adolescents have taken the first steps into examining cognitive and social-affective brain functions longitudinally with several compelling findings. First, longitudinal measurements show that activations in some brain regions, such as the prefrontal, temporal, and parietal cortex, are relatively stable over time and can be used as predictors for cognitive functions, whereas activations in other brain regions, such as the amygdala and ventral striatum, are much more variable over time. Second, developmental studies reveal how these changes are related to age, puberty, and changes in performance. These findings have implications for understanding how environmental factors influence brain development. An important future direction will be to examine individual characteristics (e.g., genetic, temperamental, personality) which make individuals differentially susceptible to their environment.

  18. The application of time-dependent ice crystal trajectory and growth model for the evaluation of cloud seeding experiment using liquid carbon dioxide

    NASA Astrophysics Data System (ADS)

    Nishiyama, K.; Wakimizu, K.; Maki, T.; Suzuki, Y.; Morita, O.; Tomine, K.

    2012-12-01

    This study evaluated the results of cloud seeding experiment conducted on 17th January, 2008, in western Kyushu, Japan, using simplified time-dependent ice crystal growth and trajectory cloud model, which is characterized by 1) depositional diffusion growth process only of an ice crystal, and 2) the pursuit of the growing ice crystal based on wind field and ice crystal terminal velocity. For the estimation of the ice crystal growth and trajectory, the model specifies ice supersaturation ratio that expresses the degree of competition growth among ice crystals formed by LC seeding for existing water vapor, assuming no effect of natural ice crystals. The model is based on ice crystal growth along a- and c-axes depending on air temperature and ice supersatuation, according to Chen and Lamb (1994). The cloud seeding experiment was conducted by applying homogeneous nucleation (rapid cooling of air mass and subsequent formation of many ice crystals~1013/g LC) of Liquid Carbon (LC) dioxide seeding under typical winter-type snowfall-inducing weather situation characterized by the outbreak of cold air masses from the Siberia. The result of aircraft horizontally-penetrating seeding of LC into lower layer (-2 degree C) of supercooled convective cloud with 1km thickness above the freezing level led to the formation of an artificially-induced 'isolated' radar echo (the left figures of Fig. 1) in dominant 'no-natural radar echo region'. In other words, natural biases were eliminated by the formation of the isolated radar echo. This fact provides the shortcut for evaluating the result of cloud seeding experiment. In the next, the observed cloud seeding results were evaluated by estimating the trajectory of artificially-induced growing ice crystal. The results show that the trajectory of artificial ice crystals depends on the degree of completion growth mode. Free growth brings rapid growth of an ice crystal and, therefore, the ice crystal falls into lower layers for a short time

  19. A mathematical model for crop spectral-temporal trajectories based on a plant growth model

    NASA Technical Reports Server (NTRS)

    Woolford, T. L.

    1983-01-01

    The Kubelka-Munk radiative transfer model is combined with an approximation of Kauth-Thomas greeness and brightness transforms to derive approximate closed form expressions for crop greeness and brightness surrogates in terms of canopy biomass. The greeness relation derived resembles an existing empirical relation between leaf area index and greeness. A simple growth model based on interception and utilization of photosynthetically active radiation is developed and used to describe the time evolution of greeness and brightness. The model developed does not yet yield definitive profile calculations but suggests a conceptual framework which may be found useful for further profile analysis.

  20. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China

    PubMed Central

    Yuan, Feng

    2016-01-01

    Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing’s shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China. PMID:26845155

  1. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China.

    PubMed

    Chen, Jianglong; Gao, Jinlong; Yuan, Feng

    2016-01-01

    Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing's shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China.

  2. Growth trajectories of alcohol information processing and associations with escalation of drinking in early adolescence

    PubMed Central

    Colder, Craig R.; O’Connor, Roisin M.; Read, Jennifer P.; Eiden, Rina D.; Lengua, Liliana J.; Hawk, Larry W.; Wieczorek, William F.

    2014-01-01

    This longitudinal study provided a comprehensive examination of age-related changes in alcohol outcome expectancies, subjective evaluation of alcohol outcomes, and automatic alcohol associations in early adolescence. A community sample (52% female, 75% White/Non-Hispanic) was assessed annually for three years (mean age at the first assessment = 11.6 years). Results from growth modeling suggested that perceived likelihood of positive outcomes increased and that subjective evaluations of these outcomes were more positive with age. Perceived likelihood of negative outcomes declined with age. Automatic alcohol associations were assessed with an Implicit Association Task (IAT), and were predominantly negative, but these negative associations weakened with age. High initial levels of perceived likelihood of positive outcomes at age 11 were associated with escalation of drinking. Perceived likelihood of negative outcomes was associated with low risk for drinking at age 11, but not with changes in drinking. Increases in positive evaluations of positive outcomes were associated with increases in alcohol use. Overall, findings suggest that at age 11, youth maintain largely negative attitudes and perceptions about alcohol, but with the transition into adolescence, there is a shift toward a more neutral or ambivalent view of alcohol. Some features of this shift are associated with escalation of drinking. Our findings point to the importance of delineating multiple aspects of alcohol information processing for extending cognitive models of alcohol use to the early stages of drinking. PMID:24841180

  3. Growth trajectories of alcohol information processing and associations with escalation of drinking in early adolescence.

    PubMed

    Colder, Craig R; O'Connor, Roisin M; Read, Jennifer P; Eiden, Rina D; Lengua, Liliana J; Hawk, Larry W; Wieczorek, William F

    2014-09-01

    This longitudinal study provided a comprehensive examination of age-related changes in alcohol outcome expectancies, subjective evaluation of alcohol outcomes, and automatic alcohol associations in early adolescence. A community sample (52% female, 75% White/non-Hispanic) was assessed annually for 3 years (mean age at the first assessment = 11.6 years). Results from growth modeling suggested that perceived likelihood of positive outcomes increased and that subjective evaluations of these outcomes were more positive with age. Perceived likelihood of negative outcomes declined with age. Automatic alcohol associations were assessed with an Implicit Association Task (IAT), and were predominantly negative, but these negative associations weakened with age. High initial levels of perceived likelihood of positive outcomes at age 11 were associated with escalation of drinking. Perceived likelihood of negative outcomes was associated with low risk for drinking at age 11, but not with changes in drinking. Increases in positive evaluations of positive outcomes were associated with increases in alcohol use. Overall, findings suggest that at age 11, youth maintain largely negative attitudes and perceptions about alcohol, but with the transition into adolescence, there is a shift toward a more neutral or ambivalent view of alcohol. Some features of this shift are associated with escalation of drinking. Our findings point to the importance of delineating multiple aspects of alcohol information processing for extending cognitive models of alcohol use to the early stages of drinking.

  4. Latent Growth Trajectories of Substance Use among Pregnant and Parenting Adolescents

    PubMed Central

    Spears, Gwendolyn V.; Stein, Judith A.; Koniak-Griffin, Deborah

    2010-01-01

    We examine changes among adolescent girls in substance use during pregnancy and the postpartum period. Three separate latent growth curve analyses assessed the impact of psychosocial, behavioral, and sociodemographic factors on resumption of or change in use of cigarettes, alcohol, and marijuana. The Vulnerable Populations Model for Research and Clinical Practice (Flaskerud & Winslow, 1998) provided the theoretical foundation for this study. This is a secondary analysis of data from a sample of 305 ethnic minority females (245 Latina, 60 African-American), aged 13–18 years, who were pregnant at baseline and were participating in an HIV prevention study conducted in inner-city alternative schools in Los Angeles County. Data collected at four time points captured changes in substance use from pregnancy through the postpartum period. Baseline predictors included ethnicity/race, partner substance use, childhood abuse history, religiosity, acculturation, depressive symptoms, length of gestation at baseline, and prior substance use. Common predictors of greater resumption and/or greater level of use included greater history of use prior to pregnancy, partner substance use, childhood abuse, and a longer time since childbirth. African Americans were more likely to be smoking at baseline when they were still pregnant and to use marijuana postpartum; Latinas were more likely to use alcohol over the course of pregnancy and postpartum. Other variables exerted an influence on specific substances. For instance, religiosity impacted cigarette and alcohol use. Findings may assist prenatal care providers to identify and counsel pregnant adolescents at risk for perinatal substance use and to prevent resumption or initiation of substance use following childbirth. PMID:20565158

  5. Exponential growth of dental schools in Chile: effects on academic, economic and workforce issues.

    PubMed

    Cartes-Velásquez, Ricardo Andrés

    2013-01-01

    In the last 30 years, Chile has undergone noteworthy economic development and an exponential growth in the access of its population to higher education. The aim of this paper was to review the changes in academic, economic and workforce issues that occurred as a consequence of the growth in supply of undergraduate dental vacancies between 1997 and 2011. Data collected from the Consejo de Educación Superior - CES, Comisión Nacional de Acreditación - CNA, and Instituto Nacional de Estadísticas de Chile - INE included these variables: number of dental schools, school type (private or traditional, see explanation below), city where the school is located, entry vacancies, total student enrollment, admission scores, percentile rank of dentistry as a university career, tuition fees, accreditation status, and number of inhabitants. There was an exponential increase in dental schools in Chile (5 to 34) that occurred in association with the rise in tuition fees (US$ 3900 to US$ 9800), a deterioration in the academic level of dental students (650 to 550 points in admission scores) and a predicted 77.5% oversupply of dentists by 2025, according to WHO criteria. The exponential increase in dental schools in Chile brought about negative consequences, such as increasing career costs, deterioration in the academic level of dental students, and an oversupply of dentists, associated with lower incomes and possibly leading to unemployment. Additional research should be conducted to determine whether an increase in the number of dentists can improve the population's access to dental care and reduce the oral disease burden.

  6. Growth trajectories are influenced by breast-feeding and infant health in an afro-colombian community.

    PubMed

    Alvarado, Beatriz Eugenia; Zunzunegui, Maria Victoria; Delisle, Hélène; Osorno, Jairo

    2005-09-01

    We conducted a longitudinal study among an Afro-Colombian population to investigate the influence of feeding practices and child morbidity on linear and ponderal growth during infancy. We enrolled 133 children at 5-7 mo and followed them until 18 mo. Repeated anthropometric measures were taken every 2-3 mo, with monthly interviews on feeding practices and daily self-reports on morbid conditions by the mothers of the infants. Mothers' social conditions and infants' fixed variables (gender and gestational age at birth) were measured at baseline. Growth starting points and trajectories were modeled via Hierarchical Linear Models (HLM). Children started with a mean length of 64.8 cm (95% CI: 59.8-69.7) and a mean weight of 7.68 kg (95% CI: 5.37-9.9), and gained length at a rate of 1.13-1.70 cm/mo, and weight at 66.5-319 g/mo. Breast-feeding, defined as receiving breast milk at any time within a 2-3-mo interval, was positively related to length gain (regression coefficient = 0.27 cm/mo; P = 0.04), after adjusting for social conditions and food consumption. Among mothers with low levels of education, breast-feeding had a positive effect on weight gain (regression coefficient = 0.30 kg/mo; P = 0.04); among nonbreast-fed infants, complementary food diversity generated a positive effect on weight (regression coefficient = 0.14 kg/mo; P = 0.03). Mean differences in length were related to the total proportion of healthy time (regression coefficient = 3.1; P = 0.02), whereas weight-gain rates were negatively associated with changes during illness (regression coefficient = -0.70; P = 0.04 for fever). No association was found between diarrhea episodes and infant growth. Our study confirms that breast-feeding after 6 mo of life is important for nutrition and health, likely by mitigating the negative effects of poor social conditions and diarrhea on infant growth.

  7. Going for growth: improvement in the infrastructural and management support for clinical academic research

    PubMed Central

    Fowler Davis, Sally

    2015-01-01

    managers in each professional group to champion research and undertake the organisational change that would be needed. The two cycles of improvement over 14 months were used to achieve “academic status” within the organisation, to include clinical staff in the delivery of the research strategy and to create a clinical academic infrastructure that incorporated a well organised public and patient involvement (PPI) panel. Additional measures included the level of participation of clinical academic staff in grant capture and the level of income from research to sustain the growth in activity. PMID:26734386

  8. Going for growth: improvement in the infrastructural and management support for clinical academic research.

    PubMed

    Fowler Davis, Sally

    2015-01-01

    each professional group to champion research and undertake the organisational change that would be needed. The two cycles of improvement over 14 months were used to achieve "academic status" within the organisation, to include clinical staff in the delivery of the research strategy and to create a clinical academic infrastructure that incorporated a well organised public and patient involvement (PPI) panel. Additional measures included the level of participation of clinical academic staff in grant capture and the level of income from research to sustain the growth in activity.

  9. Effect of Trajectories of Friends' and Parents' School Involvement on Adolescents' Engagement and Achievement

    PubMed Central

    Im, Myung Hee; Hughes, Jan N.; West, Stephen G.

    2016-01-01

    In a sample of 527 academically at-risk youth, we investigated trajectories of friends' and parents' school involvement across ages 12–14 and the joint contributions of these trajectories to adolescents' age 15 school engagement and academic achievement. Girls reported higher levels of friends' and parents' school involvement than boys. Both parents' and friends' school involvement declined across ages 12–14. Combined latent growth models and structural equation models showed effects of the trajectories of friends' and parents' school involvement on adolescents' age 15 school engagement and academic achievement, over and above adolescents' prior performance. These effects were additive rather than interactive. Strategies for enhancing parent involvement in school and students' affiliation with peers who are positively engaged in school are discussed. PMID:28239244

  10. Effect of Trajectories of Friends' and Parents' School Involvement on Adolescents' Engagement and Achievement.

    PubMed

    Im, Myung Hee; Hughes, Jan N; West, Stephen G

    2016-12-01

    In a sample of 527 academically at-risk youth, we investigated trajectories of friends' and parents' school involvement across ages 12-14 and the joint contributions of these trajectories to adolescents' age 15 school engagement and academic achievement. Girls reported higher levels of friends' and parents' school involvement than boys. Both parents' and friends' school involvement declined across ages 12-14. Combined latent growth models and structural equation models showed effects of the trajectories of friends' and parents' school involvement on adolescents' age 15 school engagement and academic achievement, over and above adolescents' prior performance. These effects were additive rather than interactive. Strategies for enhancing parent involvement in school and students' affiliation with peers who are positively engaged in school are discussed.

  11. Developmental Growth Trajectories of Self-Esteem in Adolescence: Associations with Child Neglect and Drug Use and Abuse in Young Adulthood.

    PubMed

    Oshri, Assaf; Carlson, Matthew W; Kwon, Josephine A; Zeichner, Amos; Wickrama, Kandauda K A S

    2017-01-01

    Neglectful rearing is linked with young adults' substance use and abuse, though the developmental mechanisms that underlie this association are unclear. The present study examines links between self-esteem growth during adolescence, childhood supervisory versus physical neglect severity, and substance use and abuse in young adulthood. A sample of youth was obtained from the Add Health study (N = 8738; 55.4 %-Female; 20 %-African American, 14.7 %-Hispanic). Growth mixture modeling analyses supported declining, ascending, and stable high self-esteem trajectories. The declining and ascending trajectories reported greater neglect and alcohol abuse (but not use) as well as cannabis use and abuse. The findings suggest that compromised development of self-esteem underlies associations between neglect and substance use and abuse. Preventive interventions may benefit from targeting self-esteem among neglected youth.

  12. Identifying Trajectories of Borderline Personality Features in Adolescence

    PubMed Central

    Haltigan, John D.

    2016-01-01

    Objective: To examine trajectories of adolescent borderline personality (BP) features in a normative-risk cohort (n = 566) of Canadian children assessed at ages 13, 14, 15, and 16 and childhood predictors of trajectory group membership assessed at ages 8, 10, 11, and 12. Method: Data were drawn from the McMaster Teen Study, an on-going study examining relations among bullying, mental health, and academic achievement. Participants and their parents completed a battery of mental health and peer relations questionnaires at each wave of the study. Academic competence was assessed at age 8 (Grade 3). Latent class growth analysis, analysis of variance, and logistic regression were used to analyze the data. Results: Three distinct BP features trajectory groups were identified: elevated or rising, intermediate or stable, and low or stable. Parent- and child-reported mental health symptoms, peer relations risk factors, and intra-individual risk factors were significant predictors of elevated or rising and intermediate or stable trajectory groups. Child-reported attention-deficit hyperactivity disorder (ADHD) and somatization symptoms uniquely predicted elevated or rising trajectory group membership, whereas parent-reported anxiety and child-reported ADHD symptoms uniquely predicted intermediate or stable trajectory group membership. Child-reported somatization symptoms was the only predictor to differentiate the intermediate or stable and elevated or rising trajectory groups (OR 1.15, 95% CI 1.04 to 1.28). Associations between child-reported reactive temperament and elevated BP features trajectory group membership were 10.23 times higher among children who were bullied, supporting a diathesis–stress pathway in the development of BP features for these youth. Conclusions: Findings demonstrate the heterogeneous course of BP features in early adolescence and shed light on the potential prodromal course of later borderline personality disorder. PMID:27254092

  13. Bilingualism and academic achievement.

    PubMed

    Han, Wen-Jui

    2012-01-01

    Using the Early Childhood Longitudinal Study, Kindergarten Cohort, this study examines the role that bilingualism plays in children's academic developmental trajectories during their early school years, with particular attention on the school environment (N = 16,380). Growth-curve results showed that despite starting with lower math scores in kindergarten, Mixed Bilingual children fully closed the math gap with their White English Monolingual peers by fifth grade. However, because non-English-Dominant Bilinguals and non-English Monolinguals started kindergarten with significantly lower reading and math scores compared to their English Monolingual peers, by fifth grade the former groups still had significantly lower scores. School-level factors explained about one third of the reductions in the differences in children's academic performance.

  14. The Impact of Early Academic Growth on College Readiness: A Study of a Suburban Chicago School District

    ERIC Educational Resources Information Center

    Smith, JoAnne

    2015-01-01

    The purpose of this study is to find some of the key factors determining college readiness. School districts are under increased pressure to provide all students with experiences and the preparation to ensure they are college-ready. This study investigates a few key, potential factors in the journey to college readiness: early academic growth,…

  15. The Relationship of Selected Measures of Proprioception to Physical Growth, Motor Performance, and Academic Achievement in Young Children.

    ERIC Educational Resources Information Center

    Haubenstricker, John L.; Milne, D. Conrad

    This study investigates the relationship of selected measures of proprioception to measures of physical growth, motor performance, and academic achievement in young children. Measures were obtained from 321 boys and girls attending kindergarten and first and second grade. Sample correlation matrices were computed on all variables at each grade…

  16. Growth Mixture Modelling in Developmental Psychology: Overview and Demonstration of Heterogeneity in Developmental Trajectories of Adolescent Antisocial Behaviour

    ERIC Educational Resources Information Center

    Connell, Arin M.; Frye, Alice A.

    2006-01-01

    Recent advances in statistical techniques for longitudinal data analysis have provided increased capabilities for elucidating individual differences in trajectories of change in child behaviours and abilities. However, most techniques still assume that there is a single underlying distribution with respect to changes over time, about which…

  17. The Longitudinal Relation between Academic Support and Latino Adolescents' Academic Motivation

    ERIC Educational Resources Information Center

    Alfaro, Edna C.; Umaña-Taylor, Adriana J.

    2015-01-01

    This study examined whether longitudinal trajectories of academic support from mothers, fathers, and teachers predicted trajectories of Latino adolescents' (N = 323) academic motivation. Findings indicated those boys' perceptions of mothers' and fathers' academic support and girls' perceptions of mothers' academic support declined throughout high…

  18. Trajectories of Mentors' Perceived Self-Efficacy during an Academic Mentoring Experience: What They Look Like and What Are Their Personal and Experimental Correlates?

    ERIC Educational Resources Information Center

    Larose, Simon

    2013-01-01

    In my study, mentors matched with college mentees evaluated their self-efficacy nine times, during their participation in an academic mentoring program. Three distinct groups emerged as follows: (a) mentors who perceived themselves as moderately efficient throughout the mentoring relationship (the moderate stable (MS) group), (b) mentors who…

  19. OPTIMUM TRAJECTORIES

    DTIC Science & Technology

    trajectory and the transient trajectories from the steady-state path to the endpoints could be computed separately. The results using this method agreed well with the exact solution and gave a tremendous savings in computing time....described the motion of a body similar to the one under study. The nature of the REAC solutions suggested that the steady-state, or mid-path

  20. Fostering Academic and Social Growth in a Primary Literacy Workshop Classroom: "Restorying" Students with Negative Reputations

    ERIC Educational Resources Information Center

    Worthy, Jo; Consalvo, Annamary L.; Bogard, Treavor; Russell, Katie W.

    2012-01-01

    In most classrooms, there are students who have academic, behavioral, and/or interpersonal challenges that can disrupt the classroom community. In some cases, these challenges can build momentum, leading to a negative reputation or "story" that can follow the student throughout school. This academic, yearlong case study focused on Mae Graham, an…

  1. Perceived Social Support and Academic Achievement: Cross-Lagged Panel and Bivariate Growth Curve Analyses

    ERIC Educational Resources Information Center

    Mackinnon, Sean P.

    2012-01-01

    As students transition to post-secondary education, they experience considerable stress and declines in academic performance. Perceived social support is thought to improve academic achievement by reducing stress. Longitudinal designs with three or more waves are needed in this area because they permit stronger causal inferences and help…

  2. The relationship between internalising symptom development and academic attainment in early adolescence.

    PubMed

    Patalay, Praveetha; Deighton, Jessica; Fonagy, Peter; Wolpert, Miranda

    2015-01-01

    Evidence for the longitudinal associations between internalising symptom development and academic attainment is sparse and results from existing studies are largely inconclusive. The approaches that have been used in existing studies examining this relationship have in common the limitation of grouping together all individuals in the sample which makes the assumption that the relationship between time, symptoms and attainment across all individuals is the same. The current study aimed to use heterogeneous trajectories of symptom development to examine the longitudinal associations between internalising symptom development and change in academic attainment over a three years period in early adolescence, a key period for internalising symptom development. Internalising symptoms were assessed for 3 consecutive years in a cohort from age 11-14 years (n = 2647, mean age at T1 = 11.7 years). National standardised test scores prior to the first wave and subsequent to the last wave were used as measures of academic attainment. Heterogeneous symptom development trajectories were identified using latent class growth analysis and socio-demographic correlates, such as gender, SES and ethnicity, of the different trajectory groupings were investigated. Derived trajectory groupings were examined as predictors of subsequent academic attainment, controlling for prior attainment. Results demonstrate that symptom trajectories differentially predicted change in academic attainment with increasing trajectories associated with significantly worse academic outcomes when compared to pupils with low levels of symptoms in all waves. Hence, a trajectory based approach provides a more nuanced breakdown of complexities in symptom development and their differential relationships with academic outcomes and in doing so helps clarify the longitudinal relationship between these two key domains of functioning in early adolescence.

  3. Modeling Nonlinear Change via Latent Change and Latent Acceleration Frameworks: Examining Velocity and Acceleration of Growth Trajectories

    ERIC Educational Resources Information Center

    Grimm, Kevin; Zhang, Zhiyong; Hamagami, Fumiaki; Mazzocco, Michele

    2013-01-01

    We propose the use of the latent change and latent acceleration frameworks for modeling nonlinear growth in structural equation models. Moving to these frameworks allows for the direct identification of "rates of change" and "acceleration" in latent growth curves--information available indirectly through traditional growth…

  4. Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis).

    PubMed

    Owerkowicz, Tomasz; Elsey, Ruth M; Hicks, James W

    2009-05-01

    Recent palaeoatmospheric models suggest large-scale fluctuations in ambient oxygen level over the past 550 million years. To better understand how global hypoxia and hyperoxia might have affected the growth and physiology of contemporary vertebrates, we incubated eggs and raised hatchlings of the American alligator. Crocodilians are one of few vertebrate taxa that survived these global changes with distinctly conservative morphology. We maintained animals at 30 degrees C under chronic hypoxia (12% O(2)), normoxia (21% O(2)) or hyperoxia (30% O(2)). At hatching, hypoxic animals were significantly smaller than their normoxic and hyperoxic siblings. Over the course of 3 months, post-hatching growth was fastest under hyperoxia and slowest under hypoxia. Hypoxia, but not hyperoxia, caused distinct scaling of major visceral organs-reduction of liver mass, enlargement of the heart and accelerated growth of lungs. When absorptive and post-absorptive metabolic rates were measured in juvenile alligators, the increase in oxygen consumption rate due to digestion/absorption of food was greatest in hyperoxic alligators and smallest in hypoxic ones. Hyperoxic alligators exhibited the lowest breathing rate and highest oxygen consumption per breath. We suggest that, despite compensatory cardiopulmonary remodelling, growth of hypoxic alligators is constrained by low atmospheric oxygen supply, which may limit their food utilisation capacity. Conversely, the combination of elevated metabolism and low cost of breathing in hyperoxic alligators allows for a greater proportion of metabolised energy to be available for growth. This suggests that growth and metabolic patterns of extinct vertebrates would have been significantly affected by changes in the atmospheric oxygen level.

  5. Teacher-Student Interpersonal Relationships Do Change and Affect Academic Motivation: A Multilevel Growth Curve Modelling

    ERIC Educational Resources Information Center

    Maulana, Ridwan; Opdenakker, Marie-Christine; Bosker, Roel

    2014-01-01

    Background: Research has shown that the teacher-student interpersonal relationship (TSIR) is important for student motivation. Although TSIR has received a growing interest, there are only few studies that focus on changes and links between TSIR and student academic motivation in a longitudinal fashion in non-Western contexts. Aims: This study…

  6. Elementary to High School Students' Growth over an Academic Year in Understanding Concepts of Matter

    ERIC Educational Resources Information Center

    Liu, Xiufeng

    2007-01-01

    This paper reports findings on the changes in students' understandings of the concept of matter during an academic year, for students from grade 3 through high school chemistry. The instrument for measuring students' understandings of matter consists of three forms: one for grades 3-6, one for grades 7-9, and one for grades 10-12. The three forms…

  7. Journeys of Growth towards the Professional Learning of Academics: Understanding the Role of Educational Development

    ERIC Educational Resources Information Center

    van Schalkwyk, Susan; Cilliers, Francois; Adendorff, Hanelie; Cattell, Karin; Herman, Nicoline

    2013-01-01

    This article foregrounds the iterative journey of a group of educational development (ED) practitioners at a research-led university towards an enhanced understanding of the ED opportunities we offer. Reflecting on the intention of our interventions to facilitate academics' professional learning, we developed a framework within which the range of…

  8. Predictors of Early Growth in Academic Achievement: The Head-Toes-Knees-Shoulders Task

    ERIC Educational Resources Information Center

    McClelland, Megan M.; Cameron, Claire E.; Duncan, Robert; Bowles, Ryan P.; Acock, Alan C.; Miao, Alicia; Pratt, Megan E.

    2014-01-01

    Children's behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by…

  9. Holistic Growth of College Peer Study Group Participants: Prompting Academic and Personal Development

    ERIC Educational Resources Information Center

    Arendale, David R.; Hane, Amanda R.

    2014-01-01

    This qualitative study focused on observed and perceived changes in academic and personal attitudes and behaviors by student participants in the Peer Assisted Learning (PAL) program at the University of Minnesota (UMN). The PAL model employs best practices from national peer learning models including Supplemental Instruction, Peer-led Team…

  10. Self-Reflection, Growth Goals, and Academic Outcomes: A Qualitative Study

    ERIC Educational Resources Information Center

    Martin, Andrew; Travers, Cheryl J.; Morisano, Dominique; Locke, Edwin A.

    2015-01-01

    Background: Goal-setting theory continues to be among the most popular and influential theories of motivation and performance, although there have been limited academic applications relative to applications in other domains, such as organizational psychology. Aims: This paper summarizes existing quantitative research and then employs a qualitative…

  11. Trajectory Analysis

    NASA Technical Reports Server (NTRS)

    Burke, Laura M.

    2004-01-01

    The Systems Analysis Branch performs trajectory and systems analysis for next-generation launch vehicle and space transportation technologies. Currently the branch is supporting the Project Prometheus with analysis of nuclear electric and nuclear thermal propulsion missions to a variety of destinations. Within Project Prometheus a proposed mission to Jupiter and three of the planet sized icy moons that orbit it is developing. The Jupiter Icy Moons Orbiter (JIMO) as the project is being called will enable detailed scientific investigation of Jupiter's moons Callisto, Ganymede, and Europa. These moons were choose to orbit for intensive study in particular because they are each believed to have water, energy, and organic material. The JIMO mission will utilize nuclear fission power and electric propulsion in order to allow the spacecraft to orbit the moons at close range for long durations of time. My assignment this summer was to assist in developing a trajectory analysis for the spacecraft system the Jupiter Icy Moons Orbiter by rewriting an inefficient Excel file into a more efficient FORTRAN program. This program has been created for use planning the trajectory of the Jupiter Icy Moons Orbiter Mission. The program uses a database of thousands of data points representing flight time, burn time, thrust, mass of the propellant used, final mass of the spacecraft, ratio of finals mass to initial mass, and change in velocity that a spacecraft experiences during each phase in the Jupiter Icy Moons Orbiter Mission. The trajectory program is capable of taking a specific user entered specific impulse (isp), final mass fraction, and thrust (P(sub J)/m0) and through the use of cubic splines to fit specific data curves, the program can locate the exact flight time linked to the user specified values of specific impulse and final over initial mass fraction. Currently, the database used by the program to calculate flight times for a given thrust is only for isps in the range of

  12. Examining the Earnings Trajectories of Community College Students Using a Piecewise Growth Curve Modeling Approach. A CAPSEE Working Paper

    ERIC Educational Resources Information Center

    Jaggars, Shanna Smith; Xu, Di

    2015-01-01

    Policymakers have become increasingly concerned with measuring--and holding colleges accountable for--students' labor market outcomes. In this paper we introduce a piecewise growth curve approach to analyzing community college students' labor market outcomes, and we discuss how this approach differs from Mincerian and fixed-effects approaches. Our…

  13. Individual growth trajectories of sibling Brycon moorei raised in isolation since egg stage, and their relationship with aggressive behaviour.

    PubMed

    Baras, E; Lucas, M C

    2010-09-01

    The growth of sibling dorada Brycon moorei (Characidae) housed individually in small enclosures (0·25 l; 27·0° C, range ±0·5° C; 12L:12D) from the egg stage was examined at regular intervals until 36 days after hatching (dah) and compared with their behaviour. From 1 to 8 dah, when cannibalism is intense among B. moorei raised in groups, there was no significant increase of size heterogeneity among isolated fish (c.v. of total length of 3·1 and 3·6%, at 1 and 8 dah, respectively) and no primacy of early size differences either. These results suggest that cannibals of B. moorei raised in groups are not natural-born killers with greater growth capacities than others. Size heterogeneity among isolated fish increased significantly first when B. moorei were weaned on formulated feed (8-15 dah), then again from 24 to 36 dah when the average growth rate was half as fast as before (c. 0·5 v. 1·0 mm day(-1) ), despite fish consistently feeding. During both periods, there was a significant, positive relationship between individual growth and aggression or boldness. These results suggest that (1) boldness can favour the transition to a new food type and (2) fish exhibited a variable responsiveness to spatial restriction in small enclosures, which may have been alleviated in some individuals by establishment of territorial behaviour, as suggested by their enhanced aggression.

  14. Exploring the Different Trajectories of Analytical Thinking Ability Factors: An Application of the Second-Order Growth Curve Factor Model

    ERIC Educational Resources Information Center

    Saengprom, Narumon; Erawan, Waraporn; Damrongpanit, Suntonrapot; Sakulku, Jaruwan

    2015-01-01

    The purposes of this study were 1) Compare analytical thinking ability by testing the same sets of students 5 times 2) Develop and verify whether analytical thinking ability of students corresponds to second-order growth curve factors model. Samples were 1,093 eighth-grade students. The results revealed that 1) Analytical thinking ability scores…

  15. Self-Esteem Trajectories among Ethnic Minority Adolescents: A Growth Curve Analysis of the Patterns and Predictors of Change

    ERIC Educational Resources Information Center

    Greene, Melissa L.; Way, Niobe

    2005-01-01

    The current study presents a growth curve analysis of self-esteem among Black, Latino, and Asian American high school students. A series of hierarchical linear models were used to examine patterns and predictors of change in self-esteem over time. Results revealed an average increase in self-esteem with age. Although boys and girls experienced…

  16. The effect of sub-lethal increases in temperature on the growth and population trajectories of three scleractinian corals on the southern Great Barrier Reef.

    PubMed

    Edmunds, Peter J

    2005-12-01

    To date, coral death has been the most conspicuous outcome of warming tropical seas, but as temperatures stabilize at higher values, the consequences for the corals remaining will be mediated by their demographic responses to the sub-lethal effects of temperature. To gain insight into the nature of these responses, here I develop a model to test the effect of increased temperature on populations of three pocilloporid corals at One Tree Island, near the southern extreme of the Great Barrier Reef (GBR). Using Seriatopora hystrix, S. caliendrum and Pocillopora damicornis as study species, the effects of temperature on growth were determined empirically, and the dynamics of their populations determined under natural temperatures over a 6-month period between 1999 and 2000 [defined as the study year (SY)]. The two data sets were combined in a demographic test of the possibility that the thermal regime projected for the southern GBR in the next 55-83 years--warmer by 3 degrees C than the study year (the SY+3 regime), which is equivalent to 1.4 degrees C warmer than the recent warm year of 1998--would alter coral population trajectories through the effects on coral growth alone; the analyses first were completed by species, then by family after pooling among species. Laboratory experiments showed that growth rates (i.e., calcification) varied significantly among species and temperatures, and displayed curvilinear thermal responses with growth maxima at approximately 27.1 degrees C. Based on these temperature-growth responses, the SY+3 regime is projected to: (1) increase annualized growth rates of all taxa by 24-39%, and defer the timing of peak growth from the summer to the autumn and spring, (2) alter the intrinsic rate of population growth (lambda) for S. hystrix (lambda decreases 26%) and S. caliendrum (lambda increases 5%), but not for P. damicornis, and (3) have a minor effect on lambda (a 0.3% increase) for the Pocilloporidae, largely because lambda varies more

  17. Long-term growth trajectories in a changing climate: disentangling age from size effects in old Fagus trees from contrasting bioclimates

    NASA Astrophysics Data System (ADS)

    Di Filippo, Alfredo; Piovesan, Gianluca

    2016-04-01

    Understanding the drivers promoting exceptional longevity in trees and how their growth performances vary approaching maximum lifespan still represent intriguing challenges not only for tree biology, but also for modelling the long-term forest ecosystem functioning under a changing environment. Tree growth rate is expected to increase with increasing stem size, but higher risk of hydraulic failure and mortality can affect larger trees under increasingly dry conditions. In turn, very old trees are characterized by slow growth and smaller size, factors able to confer advantages against biotic and abiotic disturbances. Rising evidences that very old trees are negligibly affected by the progressive deterioration of physiological functions associated with age support the idea that size, not age, is the main constrain to tree lifespan, so that negative senescence has been proposed as a frequent phenomenon in trees. Additional empirical knowledge is needed to thoroughly assess how complex, uneven-aged old-growth forests cope under climate change in order to define their role in terrestrial carbon cycle. We used a tree-ring network of 8 European beech (Fagus sylvatica L.) old-growth forests containing several of the oldest crossdated broadleaf trees of the Northern Hemisphere (400-600 years old) to analyse how their growth rates vary along age/size development. We sampled advanced old-growth stands, where canopy tree mortality is naturally occurring, divided among contrasting bioclimatic conditions: eastern Alps and central Apennines (rainy vs. dry summer). To disentangle the long-term effects of size and age on long-term tree growth history, we reconstructed Basal Area Increment (BAI) along size (DBH) development, grouping growth trajectories in different age classes. On average, BAI increased continuously as stem size increased, regardless of bioclimatic region and age class. Old trees grew the slowest and kept increasing BAI trends. In turn, especially on the drier

  18. Brain-region–specific alterations of the trajectories of neuronal volume growth throughout the lifespan in autism

    PubMed Central

    2014-01-01

    Several morphometric studies have revealed smaller than normal neurons in the neocortex of autistic subjects. To test the hypothesis that abnormal neuronal growth is a marker of an autism-associated global encephalopathy, neuronal volumes were estimated in 16 brain regions, including various subcortical structures, Ammon’s horn, archicortex, cerebellum, and brainstem in 14 brains from individuals with autism 4 to 60 years of age and 14 age-matched control brains. This stereological study showed a significantly smaller volume of neuronal soma in 14 of 16 regions in the 4- to 8-year-old autistic brains than in the controls. Arbitrary classification revealed a very severe neuronal volume deficit in 14.3% of significantly altered structures, severe in 50%, moderate in 21.4%, and mild in 14.3% structures. This pattern suggests desynchronized neuronal growth in the interacting neuronal networks involved in the autistic phenotype. The comparative study of the autistic and control subject brains revealed that the number of structures with a significant volume deficit decreased from 14 in the 4- to 8-year-old autistic subjects to 4 in the 36- to 60-year-old. Neuronal volumes in 75% of the structures examined in the older adults with autism are comparable to neuronal volume in age-matched controls. This pattern suggests defects of neuronal growth in early childhood and delayed up-regulation of neuronal growth during adolescence and adulthood reducing neuron soma volume deficit in majority of examined regions. However, significant correction of neuron size but limited clinical improvements suggests that delayed correction does not restore functional deficits. PMID:24612906

  19. Fetal growth trajectories in pregnancies of European and South Asian mothers with and without gestational diabetes, a population-based cohort study

    PubMed Central

    Jenum, Anne Karen; Yajnik, Chittaranjan S.; Mørkrid, Kjersti; Nakstad, Britt; Rognerud-Jensen, Odd Harald; Birkeland, Kåre I.; Vangen, Siri

    2017-01-01

    Objective Our aim was to examine the impact of gestational diabetes (GDM), from before the GDM-diagnosis is made, on fetal growth trajectories, and to compare it in Europeans and South Asians; two ethnic groups with dissimilar fetal growth patterns. Methods We studied European (n = 349) and South Asian (n = 184) pregnant women, from the population-based STORK-Groruddalen cohort in Oslo, Norway. Mothers were enrolled in early pregnancy, screened for GDM in gestational week 28 ±2, and classified as “non-GDM”, “mild GDM” or “moderate/severe GDM”. We measured fetal head circumference, abdominal circumference and femur length by ultrasound, and estimated fetal weight in gestational week 24, 32 and 37, and performed corresponding measurements at birth. Results In non-GDM pregnancies, South Asian fetuses (n = 156) had a slower growth from gestational week 24, compared with Europeans (n = 310). More than two thirds of the European mothers later diagnosed with GDM were overweight or obese in early pregnancy, while this was not observed in South Asians. Fetuses of GDM mothers tended to be smaller than fetuses of non-GDM mothers in week 24, but thereafter grew faster until birth. This pattern was especially pronounced in fetuses of South Asian mothers with moderate/severe GDM. In week 24 these fetuses had a -0.95 SD (95% CI: -1.53, -0.36) lower estimated fetal weight than their non-GDM counterparts. In contrast, at birth they were 0.45 SD (0.09, 0.81) larger. Conclusions Offspring of GDM mothers were smaller in mid pregnancy, but subsequently grew faster until birth, compared with offspring of non-GDM mothers. This pattern was most prominent in South Asian mothers with moderate to severe GDM. However, the most remarkable characteristic of these fetuses was not a large size at birth, but the small size in mid pregnancy, before the GDM diagnosis was set. PMID:28253366

  20. First-grade retention in the Flemish educational context: Effects on children's academic growth, psychosocial growth, and school career throughout primary education.

    PubMed

    Goos, Mieke; Van Damme, Jan; Onghena, Patrick; Petry, Katja; de Bilde, Jerissa

    2013-06-01

    This study examined the effects of first-grade retention on children's academic growth, psychosocial growth, and future school career by following a cohort of first graders until the start of secondary school. The study took place in the Flemish educational context where primary school students are taught in uniform curricular year groups; the same curricular goals are set for all students, irrespective of ability; and grade retention is used as the main way to cater for students not reaching these goals. Propensity score stratification was used to deal with selection bias. Three-level curvilinear growth curve models, encompassing both grade and age comparisons, were used to model children's growth in math skills, reading fluency skills, and psychosocial skills. Two-level logistic regression models were used to model children's likelihood of repeating any grade between Grades 2 and 6, transitioning to a special education primary school, moving to another primary school, and transitioning to the A (versus B) track in secondary education. Overall, results showed that first-grade retention was less helpful for struggling students than generally thought by parents and educators. Limitations of the study and further research suggestions are provided, and practical implications are discussed.

  1. Distinct trajectories in the transition to adulthood: are children of immigrants advantaged?

    PubMed

    Hao, Lingxin; Woo, Han S

    2012-01-01

    Studies on children of immigrants have generally ignored distinct developmental trajectories during adolescence and their role in the transition to adulthood. This study identifies distinct trajectories in cognitive, sociobehavioral, and psychological domains and estimates their consequences for young adults. Drawing data from a nationally representative sample of 10,795 adolescents aged 13-17 who were followed up to ages 25-32, the study uses growth mixture modeling to test advantages for children of immigrants. The analysis shows a 1.5-generation advantage in academic achievement and school engagement, as well as a weaker second-generation advantage in academic achievement, but no disadvantage in depression for children of immigrants. In addition, these results hold for children of Hispanic origin. Theoretical and policy implications are discussed.

  2. RETADD-II: a long-range atmospheric trajectory model with consistent treatment of deposition loss and species growth and decay

    SciTech Connect

    Murphy, B.D.; Ohr, S.Y.; Begovich, C.L.

    1984-08-01

    A versatile model is described which estimates long-range atmospheric dispersion based on plume trajectories. This model allows the treatment of the dispersal from a source at an arbitrary height while taking account of plume depletion by dry and wet deposition together with the decay of material to successor species. The plume depletion, decay and growth equations are solved in an efficient manner which can accommodate up to eight pollutants (i.e., a parent and seven serial decay products). The code is particularly suitable for applications involving radioactive chain decay or for cases involving chemical species with successor decay products. Arbitrary emission rates can be specified for the members of the chain or, as is commonly the case, a sole emission rate can be specified for the first member. The code uses readily available upper-air wind data for the North American continent and it is therefore intended for the estimation of regional or continental scale dispersion patterns. This code is one of a group of codes, the Computerized Radiological Risk Investigation System (Baes and Miller, 1981), designed to simulate the transport of radionuclides through environmental pathways. 24 references, 5 figures.

  3. Direct and maternal genetic effects for preweaning growth in Retinta cattle estimated by a longitudinal approach throughout the calving trajectory of the cow.

    PubMed

    Morales, R; Menéndez-Buxadera, A; Avilés, C; Molina, A

    2013-12-01

    The direct and maternal genetic effects were estimated for the preweaning growth of Retinta calves with a multitrait model across parities, using a longitudinal approach with random regression models (RRM). The 120 (P120) and 180 days (P180) weights (5972 calves) were considered as different traits in each calving. The heritability of direct effect across parities was on average 0.37 for P120 and 0.58 for P180, slightly higher than the estimates by univariate (0.30 and 0.56) and bivariate models (0.30 and 0.51, respectively). The heritability for maternal effects was 0.16 for P120 and 0.26 for P180 and very similar by uni- (0.16 and 0.23) and multivariate model (0.16 and 0.22, respectively). The correlation between direct and maternal effects by RRM showed a pronounced antagonism -0.64 for P120 and -0.78 for P180), likewise uni- (-0.62 and -0.72) and multivariate case (-0.64 and -0.74, respectively). The preweaning weights should be considered as different traits across parities, because the genetic correlations were different from unity. The RRM also allowed us to estimate all the parameters throughout the calving trajectory of the cow. The use of multiple traits RRM across parities can provide very useful information for the breeding programmes.

  4. Fully aligned academic health centers: a model for 21st-century job creation and sustainable economic growth.

    PubMed

    Reece, E Albert; Chrencik, Robert A; Miller, Edward D

    2012-07-01

    Alignment is the degree to which component parts of academic health centers (AHCs) work cohesively. Full alignment allows AHCs to act quickly and cohesively toward common goals and to take advantage of opportunities that present themselves, particularly where collaboration is essential. Maryland's two major AHCs-University of Maryland Medicine (UMM) and Johns Hopkins Medicine (JHM)-have experienced periods of significant misalignment during each of their histories. Their most recent periods of misalignment caused significant negative economic and academic impacts. However, the process of realigning their clinical and research missions has not only given them a renewed economic vigor but has also paid significant dividends for the state of Maryland, helping it weather the current recession much better than other regions of the country. The two AHCs' continued economic success during the recession has led Maryland lawmakers to increasingly seek out their expertise in attempts to stimulate economic development. Indeed, UMM, JHM, and other fully aligned AHCs have shown that they can be powerful economic engines and offer a model of job growth and economic development in the 21st century.

  5. Psychological and demographic correlates of early academic skill development among American Indian and Alaska Native youth: a growth modeling study.

    PubMed

    Marks, Amy Kerivan; Coll, Cynthia García

    2007-05-01

    Research regarding the development of early academic skills among American Indian and Alaska Native (AIAN) students has been very limited to date. Using a nationally representative sample of AIAN, Hispanic, African American, and White children at school entry, the authors used latent growth models to estimate the associations among poverty, low parental education, living in a rural location, as well as child attitudes toward learning and internalizing/externalizing behaviors, with mathematical and reading cognitive skill development across the 1st 4 years of school. Results indicate that AIAN children entered kindergarten with scores on both mathematical and reading cognitive tests that were comparable to their peers from other ethnic groups of color. Importantly, all children who entered kindergarten with lower cognitive skill scores also acquired skills more slowly over the next 4 years. Having a positive approach to learning at the start of kindergarten was associated with cognitive skill levels at school entry nearly 1 standard deviation above the population average. Results are discussed with reference to the shared early educational profiles observed between AIAN and other children of color. These findings provide a much-needed update regarding early academic development among AIAN children.

  6. Effect of School Belonging Trajectories in Grades 6–8 on Achievement: Gender and Ethnic Differences

    PubMed Central

    Hughes, Jan N.; Im, Myung Hee; Allee, Paula J.

    2015-01-01

    This study investigated the association between trajectories of school belonging across grades 6–8 and academic achievement in grade 8 in an ethnically diverse sample of 527 academically at-risk adolescents. Students reported annually on school belonging. Reading and math achievement were assessed at grade 5 (baseline) and grade 8. Interactive effects of gender and ethnicity were found in the conditional growth models for school belonging. Girls of all ethnicities had identical growth trajectories and reported higher initial school belonging than Euro-American or Latino boys. Latino and Euro-American males had lower initial level of school belonging than African American males, and Latino males had lower growth in school belonging than Euro-American males. In structural equation modeling (SEM) analyses, initial level of school belonging predicted grade 8 reading for girls and grade 8 math for boys and girls, above prior achievement and school and child covariates, but growth in school belonging predicted grade 8 achievement only for African American students. Implications for strategies to improve school belonging among academically at-risk youth are discussed. PMID:26563601

  7. Benchmarks for Expected Annual Academic Growth for Students in the Bottom Quartile of the Normative Distribution

    ERIC Educational Resources Information Center

    Scammacca, Nancy K.; Fall, Anna-Mária; Roberts, Greg

    2015-01-01

    Effect sizes are commonly reported for the results of educational interventions. However, researchers struggle with interpreting their magnitude in a way that transcends generic guidelines. Effect sizes can be interpreted in a meaningful context by benchmarking them against typical growth for students in the normative distribution. Such benchmarks…

  8. The Effects of a Growth Mindset Intervention on the Beliefs about Intelligence, Effort Beliefs, Achievement Goal Orientations, and Academic Self-Efficacy of LD Students with Reading Difficulties

    ERIC Educational Resources Information Center

    Baldridge, Mary Caufield

    2010-01-01

    The overall purpose of this study was to examine the effects of a "growth mindset" intervention on the beliefs about intelligence, effort beliefs, achievement goals, and academic self-efficacy of learning disabled (LD) students with reading difficulties. The treatment group consisted of 12 high school LD students with reading difficulties. This…

  9. Native Language Proficiency, English Literacy, Academic Achievement, and Occupational Attainment in Limited-English-Proficient Students: A Latent Growth Modeling Perspective

    ERIC Educational Resources Information Center

    Guglielmi, R. Sergio

    2008-01-01

    The hypothesis that native language (L1) proficiency promotes English acquisition and overall academic achievement, a key theoretical assumption underlying bilingual education, was tested using latent growth modeling of data from 899 limited-English-proficient (LEP) eighth graders who were followed for 12 years in the National Education…

  10. Use of Hierarchical Linear Modeling and Curriculum-Based Measurement for Assessing Academic Growth and Instructional Factors for Students with Learning Difficulties

    ERIC Educational Resources Information Center

    Shin, Jongho; Espin, Christine A.; Deno, Stanley L.; McConnell, Scott

    2004-01-01

    The main purpose of this paper is to demonstrate how to apply the Hierarchical Linear Modeling (HLM) technique to multi-wave Curriculum-Based Measurement (CBM) measures in modeling academic growth and assessing its relations to student-and instruction-related variables. HLM has advantages over other statistical methods (e.g., repeated measures…

  11. Patterns of Crime and Drug Use Trajectories in Relation to Treatment Initiation and 5-Year Outcomes: An Application of Growth Mixture Modeling across Three Data Sets

    ERIC Educational Resources Information Center

    Prendergast, Michael; Huang, David; Hser, Yih-Ing

    2008-01-01

    Drug abusers vary considerably in their drug use and criminal behavior over time, and these trajectories are likely to influence drug treatment participation and treatment outcomes. Drawing on longitudinal natural history data from three samples of adult male drug users, we identify four groups with distinctive drug use and crime trajectories…

  12. A Case Study of Academic Growth in Schools for the Deaf: The Convergence of Educational Policy and Organizational Theory

    ERIC Educational Resources Information Center

    Virnig, Sean M.

    2013-01-01

    In this age of educational accountability, public schools are presumed to have the innate organizational capability to meet academic achievement benchmarks. Fair or not, this presumption also extends to schools serving students who are deaf, a population whose academic achievement continues to be unsatisfactory. This dissertation investigated how…

  13. Trajectories of Posttraumatic Stress Among Urban Residents

    PubMed Central

    Galea, Sandro; Uddin, Monica; Koenen, Karestan C.

    2014-01-01

    Urban residents experience a wide range of traumatic events and are at increased risk of assaultive violence. Although previous research has examined trajectories of posttraumatic stress (PTS) through latent class growth analysis (LCGA) among persons exposed to the same index events (e.g., a natural disaster), PTS trajectories have not been documented among urban residents. The aims of this study were to conduct LGCA with a sample of trauma survivors from Detroit, Michigan (N = 981), and to explore predictors of trajectory membership. Participants completed three annual telephone surveys, each of which included the posttraumatic stress disorder (PTSD) Check-list-Civilian Version. Four PTS trajectories were detected. Although the majority evidenced a trajectory of consistently few symptoms (Low: 72.5 %), 4.6 % were in a trajectory of chronic severe PTSD (High), and the remainder were in trajectories of consistently elevated, but generally subclinical, levels of PTS (Decreasing: 12.3 %; Increasing: 10.6 %). Socioeconomic disadvantage (e.g., lower income), more extensive trauma history (e.g., childhood abuse), and fewer social resources (e.g., lower social support) were associated with membership in higher PTS trajectories, relative to the Low trajectory. The results suggest that efforts to reduce PTS in urban areas need to attend to socioeconomic vulnerabilities in addition to trauma history and risk for ongoing trauma exposure. PMID:24469249

  14. Ascent trajectory dispersion analysis

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The results of a Space Transportation System ascent trajectory dispersion analysis are documented. Critical trajectory parameter values useful for the definition of lightweight external tank insulation requirements are provided. This analysis was conducted using two of the critical missions specified for the Space Transportation System: a 28.5 deg inclination trajectory launched from the Eastern Test Range (ETR) and a Western Test Range (WTR) trajectory launched into a 104 deg orbital inclination.

  15. The Effects of Middle School Bullying and Victimization on Adjustment through High School: Growth Modeling of Achievement, School Attendance, and Disciplinary Trajectories

    ERIC Educational Resources Information Center

    Feldman, Marissa A.; Ojanen, Tiina; Gesten, Ellis L.; Smith-Schrandt, Heather; Brannick, Michael; Wienke Totura, Christine M.; Alexander, Lizette; Scanga, David; Brown, Ken

    2014-01-01

    The current 5-year longitudinal study examined the effects of middle school bullying and victimization on adolescent academic achievement, disciplinary referrals, and school attendance through high school (N = 2030; 1016 both boys and girls). Greater engagement in bullying behaviors was concurrently associated with lower achievement and school…

  16. Variation in Trajectories of Women's Marital Quality

    PubMed Central

    James, Spencer L.

    2014-01-01

    I examine variation in trajectories of women's marital quality across the life course. The analysis improves upon earlier research in three ways: (1) the analysis uses a sequential cohort design and data from the first 35 years of marriage; (2) I analyze rich data from a national sample; (3) I examine multiple dimensions of marital quality. Latent class growth analyses estimated on data from women in the National Longitudinal Survey of Youth-1979 (N = 2604) suggest multiple trajectories for each of three dimensions of marital quality, including two trajectories of marital happiness, two trajectories of marital communication, and three trajectories of marital conflict. Socioeconomic and demographic covariates are then used to illustrate how factors such as income, cohabitation, and race-ethnicity set individuals at risk of poor marital quality throughout the life course by differentiating between high and low trajectories of marital quality. Women on low marital quality trajectories are, as expected, at much greater risk of divorce. Taken together, these findings show how fundamental socioeconomic and demographic characteristics contribute to subsequent marital outcomes via their influence on trajectories of marital quality as well as providing a better picture of the complexity in contemporary patterns of marital quality. PMID:25432600

  17. Variation in trajectories of women's marital quality.

    PubMed

    James, Spencer L

    2015-01-01

    I examine variation in trajectories of women's marital quality across the life course. The analysis improves upon earlier research in three ways: (1) the analysis uses a sequential cohort design and data from the first 35years of marriage; (2) I analyze rich data from a national sample; (3) I examine multiple dimensions of marital quality. Latent class growth analyses estimated on data from women in the National Longitudinal Survey of Youth-1979 (N=2604) suggest multiple trajectories for each of three dimensions of marital quality, including two trajectories of marital happiness, two trajectories of marital communication, and three trajectories of marital conflict. Socioeconomic and demographic covariates are then used to illustrate how factors such as income, cohabitation, and race-ethnicity set individuals at risk of poor marital quality throughout the life course by differentiating between high and low trajectories of marital quality. Women on low marital quality trajectories are, as expected, at much greater risk of divorce. Taken together, these findings show how fundamental socioeconomic and demographic characteristics contribute to subsequent marital outcomes via their influence on trajectories of marital quality as well as providing a better picture of the complexity in contemporary patterns of marital quality.

  18. Developmental Trajectories of Writing Skills in First Grade

    ERIC Educational Resources Information Center

    Kim, Young-Suk; Puranik, Cynthia; Al Otaiba, Stephanie

    2015-01-01

    We examined growth trajectories of writing and the relation of children's socioeconomic status and language and/or speech impairment to the growth trajectories. First-grade children (N = 304) were assessed on their written composition in the fall, winter, and spring, and their vocabulary and literacy skills in the fall. Children's SES had a…

  19. Trajectories of Martian Habitability

    PubMed Central

    2014-01-01

    Abstract Beginning from two plausible starting points—an uninhabited or inhabited Mars—this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments. Key Words: Mars—Habitability—Liquid water—Planetary science. Astrobiology 14, 182–203. PMID:24506485

  20. Proving Them Wrong: Academically Resilient First-Generation Latinas in College

    ERIC Educational Resources Information Center

    Reyes, Rosanna A.

    2012-01-01

    This study examined the educational trajectories of academically resilient first-generation Latinas in college. More specifically, the study focused on the factors that led them to become academically successful. The researcher of this study conducted a narrative inquiry analysis of the K-16 educational trajectories of five academically resilient…

  1. Optimization Of Simulated Trajectories

    NASA Technical Reports Server (NTRS)

    Brauer, Garry L.; Olson, David W.; Stevenson, Robert

    1989-01-01

    Program To Optimize Simulated Trajectories (POST) provides ability to target and optimize trajectories of point-mass powered or unpowered vehicle operating at or near rotating planet. Used successfully to solve wide variety of problems in mechanics of atmospheric flight and transfer between orbits. Generality of program demonstrated by its capability to simulate up to 900 distinct trajectory phases, including generalized models of planets and vehicles. VAX version written in FORTRAN 77 and CDC version in FORTRAN V.

  2. Music Strategies to Promote Engagement and Academic Growth of Young Children with ASD in the Inclusive Classroom

    ERIC Educational Resources Information Center

    Vaiouli, Potheini; Ogle, Lindsey

    2015-01-01

    Typical group activities for kindergarten children depend heavily on children's ability to follow directions, respond verbally to adults' prompts, take turns, initiate, and sustain peer interactions. Therefore, young children with autism may often be excluded from academic group activities because their social skills are under-developed or delayed…

  3. Changes in teachers' involvement versus rejection and links with academic motivation during the first year of secondary education: a multilevel growth curve analysis.

    PubMed

    Maulana, Ridwan; Opdenakker, Marie-Christine; Stroet, Kim; Bosker, Roel

    2013-09-01

    Research consistently shows that the learning environment plays an important role for early adolescents' learning and outcomes and suggests that good teacher-student relationships can serve as a protective factor for maintaining young adolescents' interest and active engagement in learning. However, less is known about the dynamic nature of teacher-student relationships and how they link with academic motivation development. Furthermore, little is known about the nature and the effects of teacher-student relationships in a cross-national context. The present study investigated changes in two components of teacher-student relationships (teachers' involvement vs. rejection) and examined links with students' academic motivation during the first grade of secondary school. Ten Dutch and ten Indonesian teachers (65 % female) from 24 classes were videoed 12 times across the school year, and four videos for each class were selected randomly and coded on teachers' involvement versus rejection. A total of 713 students (52 % girls) completed four-wave measures of their academic motivation after each video observation. Multilevel growth curve modeling revealed that the teacher's involvement changed in a curvilinear way and decreased across the first year of secondary education, while changes in the teacher's rejection did not follow a linear time function. Academic motivation changed in an undesirable way: controlled motivation increased, while autonomous motivation decreased over time. Teachers' involvement had a unique contribution in preventing high levels of controlled motivation in both countries. Findings suggest that teacher-student relationships (teachers' involvement) play an essential role in early adolescents' motivation regardless of the nations and should be a priority for schools.

  4. PANTHER. Trajectory Analysis

    SciTech Connect

    Rintoul, Mark Daniel; Wilson, Andrew T.; Valicka, Christopher G.; Kegelmeyer, W. Philip; Shead, Timothy M.; Newton, Benjamin D.; Czuchlewski, Kristina Rodriguez

    2015-09-01

    We want to organize a body of trajectories in order to identify, search for, classify and predict behavior among objects such as aircraft and ships. Existing compari- son functions such as the Fr'echet distance are computationally expensive and yield counterintuitive results in some cases. We propose an approach using feature vectors whose components represent succinctly the salient information in trajectories. These features incorporate basic information such as total distance traveled and distance be- tween start/stop points as well as geometric features related to the properties of the convex hull, trajectory curvature and general distance geometry. Additionally, these features can generally be mapped easily to behaviors of interest to humans that are searching large databases. Most of these geometric features are invariant under rigid transformation. We demonstrate the use of different subsets of these features to iden- tify trajectories similar to an exemplar, cluster a database of several hundred thousand trajectories, predict destination and apply unsupervised machine learning algorithms.

  5. Unpacking the associations between heterogeneous externalising symptom development and academic attainment in middle childhood.

    PubMed

    Patalay, Praveetha; Fink, Elian; Fonagy, Peter; Deighton, Jessica

    2016-05-01

    This study explores children's externalising symptom development pathways between 8 and 11 years of age (three time points across 2 years) and examines their sociodemographic correlates and associations with change in academic attainment. Externalising symptoms were assessed for 5485 children across three consecutive years (M age = 8.7 years, SD = 0.30 at time 1). National standardised test scores served as an index of academic attainment. Using latent class growth analysis, six distinct trajectories of externalising symptom development were identified. Children who showed increasing externalising symptomatology across the three time points were more likely to be male or have special educational needs. These derived trajectories differentially predicted children's subsequent academic attainment (controlling for earlier attainment). Children with increasing externalising symptomatology were significantly more likely to demonstrate negative change in academic achievement compared with children with consistently low externalising problems. The study helps to clarify the longitudinal association between externalising symptom development and academic attainment, and highlights the importance of early intervention for children with increasing externalising symptoms across middle childhood.

  6. Trajectory Browser Website

    NASA Technical Reports Server (NTRS)

    Foster, Cyrus; Jaroux, Belgacem A.

    2012-01-01

    The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center to be used for the preliminary assessment of trajectories to small-bodies and planets and for providing relevant launch date, time-of-flight and V requirements. The site hosts a database of transfer trajectories from Earth to asteroids and planets for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and delta V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release as soon as development is complete.

  7. Academic Blogging: Academic Practice and Academic Identity

    ERIC Educational Resources Information Center

    Kirkup, Gill

    2010-01-01

    This paper describes a small-scale study which investigates the role of blogging in professional academic practice in higher education. It draws on interviews with a sample of academics (scholars, researchers and teachers) who have blogs and on the author's own reflections on blogging to investigate the function of blogging in academic practice…

  8. Psychological and sociocultural adjustment of first-year international students: Trajectories and predictors.

    PubMed

    Hirai, Reiko; Frazier, Patricia; Syed, Moin

    2015-07-01

    Despite the increasing number of international students in U.S. universities, the temporal course of international students' adjustment has not been adequately tested, and only 1 study to date has examined multiple trajectories of adjustment. Therefore, the first goal of the current study was to explore multiple trajectories of adjustment among first-year international students using a broader range of adjustment measures (i.e., psychological distress, positive psychological adjustment, sociocultural adjustment). The second goal was to identify important predictors of trajectories. A wide range of individual and interpersonal predictor variables was examined, including academic stress and perceived control over academic stress, personality, social relationships, and language-related factors. Undergraduate and graduate international students in their first semester at a large midwestern university participated in this 5-wave longitudinal study (N = 248) that spanned 1 academic year. Multiple trajectories emerged, and the trajectories varied across the 3 adjustment measures. Average trajectories masked the trajectories of small groups of students who maintained or increased in terms of adjustment difficulties across outcomes. Contrary to popular theories, the U-shape adjustment trajectory (characterized by initial euphoria, distress, and then recovery) did not emerge. The most consistent predictors of adjustment trajectories were perceived present control over academic stress and Neuroticism.

  9. Three-dimensional tracking of plus-tips by lattice light-sheet microscopy permits the quantification of microtubule growth trajectories within the mitotic apparatus

    NASA Astrophysics Data System (ADS)

    Yamashita, Norio; Morita, Masahiko; Legant, Wesley R.; Chen, Bi-Chang; Betzig, Eric; Yokota, Hideo; Mimori-Kiyosue, Yuko

    2015-10-01

    Mitotic apparatus, which comprises hundreds of microtubules, plays an essential role in cell division, ensuring the correct segregation of chromosomes into each daughter cell. To gain insight into its regulatory mechanisms, it is essential to detect and analyze the behavior of individual microtubule filaments. However, the discrimination of discrete microtubule filaments within the mitotic apparatus is beyond the capabilities of conventional light microscopic technologies. Recently, we detected three-dimensional (3-D) microtubule growth dynamics within the cellular cytoplasmic space using lattice light-sheet microscopy in conjunction with microtubule growth marker protein end-binding 1, a microtubule plus-end-tracking protein, which was fused to green fluorescent protein (EB1-GFP). This technique enables high-resolution 3-D imaging at subsecond intervals. We adapted mathematical computing and geometric representation techniques to analyze spatial variations in microtubule growth dynamics within the mitotic spindle apparatus. Our analytical approach enabled the different dynamic properties of individual microtubules to be determined, including the direction and speed of their growth, and their growth duration within a 3-D spatial map. Our analysis framework provides an important step toward a more comprehensive understanding of the mechanisms driving cellular machinery at the whole-cell level.

  10. Academic Hospitality

    ERIC Educational Resources Information Center

    Phipps, Alison; Barnett, Ronald

    2007-01-01

    Academic hospitality is a feature of academic life. It takes many forms. It takes material form in the hosting of academics giving papers. It takes epistemological form in the welcome of new ideas. It takes linguistic form in the translation of academic work into other languages, and it takes touristic form through the welcome and generosity with…

  11. Consultation-based academic interventions for children with ADHD: effects on reading and mathematics achievement.

    PubMed

    DuPaul, George J; Jitendra, Asha K; Volpe, Robert J; Tresco, Katy E; Lutz, J Gary; Vile Junod, Rosemary E; Cleary, Kristi S; Flammer, Lizette M; Mannella, Mark C

    2006-10-01

    The purpose of this investigation was to evaluate the relative efficacy of two consultation-based models for designing academic interventions to enhance the educational functioning of children with attention-deficit/hyperactivity disorder (ADHD). Children (N=167) meeting DSM-IV criteria for ADHD were randomly assigned to one of two consultation groups: Individualized Academic Intervention (IAI; interventions designed using a data-based decision-making model that involved ongoing feedback to teachers) and Generic Academic Intervention (GAI; interventions designed based on consultant-teacher collaboration, representing "consultation as usual"). Teachers implemented academic interventions over 15 months. Academic outcomes (e.g., standardized achievement test, and teacher ratings of academic skills) were assessed on four occasions (baseline, 3 months, 12 months, 15 months). Hierarchical linear modeling analyses indicated significant positive growth for 8 of the 14 dependent variables; however, trajectories did not differ significantly across consultation groups. Interventions in the IAI group were delivered with significantly greater integrity; however, groups did not differ with respect to teacher ratings of treatment acceptability. The results of this study provide partial support for the effectiveness of consultation-based academic interventions in enhancing educational functioning in children with ADHD; however, the relative advantages of an individualized model over "consultation as usual" have yet to be established.

  12. MAVEN's Trajectory to Mars

    NASA Video Gallery

    This movie shows the cruise trajectory of NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission, which was launched on Nov. 18, 2013. It will arrive at Mars on Sept. 21, 2014, to explore th...

  13. Exploration of Teaching Strategies That Stimulate the Growth of Academic Skills of Children with ASD in Special Education School

    ERIC Educational Resources Information Center

    Manti, Eirini; Scholte, Evert M.; Van Berckelaer-Onnes, Ina A.

    2013-01-01

    The cognitive growth of children with developmental disorders, like autism, can be seriously impaired due to the disorder. If so, in the Netherlands, these children can attend special schools where they are treated to ameliorate disorder symptoms and to stimulate cognitive growth. The aim of this paper was to identify teaching strategies that…

  14. The Use of Piecewise Growth Models to Estimate Learning Trajectories and RtI Instructional Effects in a Comparative Interrupted Time-Series Design

    ERIC Educational Resources Information Center

    Zvoch, Keith

    2016-01-01

    Piecewise growth models (PGMs) were used to estimate and model changes in the preliteracy skill development of kindergartners in a moderately sized school district in the Pacific Northwest. PGMs were applied to interrupted time-series (ITS) data that arose within the context of a response-to-intervention (RtI) instructional framework. During the…

  15. The role of energy composition of diet affects muscle programming and fiber recruitment, body composition, and growth trajectory in rainbow trout

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing production feed efficiency in aquaculture requires not only knowing the available energy for certain dietary components but understanding how they are interactively processed. For most aquaculture production muscle growth is of high priority. Nutrigenomics is a promising discipline to aug...

  16. The Impact of Salient Role Stress on Trajectories of Health in Late Life among Survivors of a Seven-Year Panel Study: Analyses of Individual Growth Curves

    ERIC Educational Resources Information Center

    Shaw, Benjamin A.; Krause, Neal

    2002-01-01

    The purpose of this study is twofold: 1) to model changes in health over time among older adults; and 2) to assess the degree to which stress arising in salient social roles accounts for individual variation in these changes. Individual growth curve analyses using Hierarchical Linear Modeling (HLM) software were employed with longitudinal data…

  17. Automated Cooperative Trajectories

    NASA Technical Reports Server (NTRS)

    Hanson, Curt; Pahle, Joseph; Brown, Nelson

    2015-01-01

    This presentation is an overview of the Automated Cooperative Trajectories project. An introduction to the phenomena of wake vortices is given, along with a summary of past research into the possibility of extracting energy from the wake by flying close parallel trajectories. Challenges and barriers to adoption of civilian automatic wake surfing technology are identified. A hardware-in-the-loop simulation is described that will support future research. Finally, a roadmap for future research and technology transition is proposed.

  18. Optimum Three Impulse Trajectory Generator with Patched Conic Trajectory Model

    NASA Technical Reports Server (NTRS)

    Payne, M. H.; Pines, S.; Horsewood, J. L.

    1972-01-01

    Optimal multi-impulse trajectories were investigated as a nominal about which asymptotic expansion was used to obtain approximations of optimal low thrust trajectories. The work consisted of the analysis and description of an optimal 3-impulse trajectory program. A patched-conic trajectory model was specifically designed for compatibility with the subsequent addition of the low thrust expansion approximation.

  19. An application of analyzing the trajectories of two disorders: A parallel piecewise growth model of substance use and attention-deficit/hyperactivity disorder.

    PubMed

    Mamey, Mary Rose; Barbosa-Leiker, Celestina; McPherson, Sterling; Burns, G Leonard; Parks, Craig; Roll, John

    2015-12-01

    Researchers often want to examine 2 comorbid conditions simultaneously. One strategy to do so is through the use of parallel latent growth curve modeling (LGCM). This statistical technique allows for the simultaneous evaluation of 2 disorders to determine the explanations and predictors of change over time. Additionally, a piecewise model can help identify whether there are more than 2 growth processes within each disorder (e.g., during a clinical trial). A parallel piecewise LGCM was applied to self-reported attention-deficit/hyperactivity disorder (ADHD) and self-reported substance use symptoms in 303 adolescents enrolled in cognitive-behavioral therapy treatment for a substance use disorder and receiving either oral-methylphenidate or placebo for ADHD across 16 weeks. Assessing these 2 disorders concurrently allowed us to determine whether elevated levels of 1 disorder predicted elevated levels or increased risk of the other disorder. First, a piecewise growth model measured ADHD and substance use separately. Next, a parallel piecewise LGCM was used to estimate the regressions across disorders to determine whether higher scores at baseline of the disorders (i.e., ADHD or substance use disorder) predicted rates of change in the related disorder. Finally, treatment was added to the model to predict change. While the analyses revealed no significant relationships across disorders, this study explains and applies a parallel piecewise growth model to examine the developmental processes of comorbid conditions over the course of a clinical trial. Strengths of piecewise and parallel LGCMs for other addictions researchers interested in examining dual processes over time are discussed.

  20. An application of analyzing the trajectories of two disorders: A parallel piecewise growth model of substance use and attention deficit/hyperactivity disorder

    PubMed Central

    Mamey, Mary Rose; Barbosa-Leiker, Celestina; McPherson, Sterling; Burns, G. Leonard; Parks, Craig; Roll, John

    2015-01-01

    Researchers often want to examine two comorbid conditions simultaneously. One strategy to do so is through the use of parallel latent growth curve modeling (LGCM). This statistical technique allows for the simultaneous evaluation of two disorders to determine the explanations and predictors of change over time. Additionally, a piecewise model can help identify whether there are more than two growth processes within each disorder (e.g., during a clinical trial). A parallel piecewise LGCM was applied to self-reported attention deficit/hyperactivity disorder (ADHD) and self-reported substance use symptoms in 303 adolescents enrolled in cognitive behavioral therapy treatment for a substance use disorder (SUD) and receiving either oral-methylphenidate or placebo for ADHD across 16 weeks. Assessing these two disorders concurrently allowed us to determine whether elevated levels of one disorder predicted elevated levels or increased risk of the other disorder. First, a piecewise growth model measured ADHD and SU separately. Next, a parallel piecewise LGCM was used to estimate the regressions across disorders to determine whether higher scores at baseline of the disorders (i.e., ADHD or SUD) predicted rates of change in the related disorder. Finally, treatment was added to the model to predict change. While the analyses revealed no significant relationships across disorders, this study explains and applies a parallel piecewise growth model to examine the developmental processes of comorbid conditions over the course of a clinical trial. Strengths of piecewise and parallel LGCMs for other addictions researchers interested in examining dual processes over time are discussed. PMID:26389639

  1. Charting Early Trajectories of Executive Control with the Shape School

    ERIC Educational Resources Information Center

    Clark, Caron A. C.; Sheffield, Tiffany D.; Chevalier, Nicolas; Nelson, Jennifer Mize; Wiebe, Sandra A.; Espy, Kimberly Andrews

    2013-01-01

    Despite acknowledgement of the importance of executive control for learning and behavior, there is a dearth of research charting its developmental trajectory as it unfolds against the background of children's sociofamilial milieus. Using a prospective, cohort-sequential design, this study describes growth trajectories for inhibitory control…

  2. Predictors of Latent Trajectory Classes of Physical Dating Violence Victimization

    ERIC Educational Resources Information Center

    Brooks-Russell, Ashley; Foshee, Vangie A.; Ennett, Susan T.

    2013-01-01

    This study identified classes of developmental trajectories of physical dating violence victimization from grades 8 to 12 and examined theoretically-based risk factors that distinguished among trajectory classes. Data were from a multi-wave longitudinal study spanning 8th through 12th grade (n = 2,566; 51.9 % female). Growth mixture models were…

  3. Exploring Categorical Body Mass Index Trajectories in Elementary School Children

    ERIC Educational Resources Information Center

    Moreno-Black, Geraldine; Boles, Shawn; Johnson-Shelton, Deb; Evers, Cody

    2016-01-01

    Background: Studies of body mass index (BMI) change have focused on understanding growth trajectories from childhood to adolescence and adolescence to adulthood, but few have explored BMI trajectories solely in elementary (grades K-5) school children. This report complements these studies by exploring changes in obesity status using analytic…

  4. Parental involvement and African American and European American adolescents' academic, behavioral, and emotional development in secondary school.

    PubMed

    Wang, Ming-Te; Hill, Nancy E; Hofkens, Tara

    2014-01-01

    This study examined longitudinal trajectories of parental involvement across middle and high school, and how these trajectories related to adolescents' academic, behavioral, and emotional adjustment. In addition, ethnic and socioeconomic status differences in longitudinal associations and the potential moderating role of parental warmth were assessed. Longitudinal growth modeling technique was used to describe trajectories of different types of parental involvement and adolescent outcomes over 7th, 9th, and 11th grades (mean ages = 12.9, 14.3, and 17.2 years, respectively) on an ethnically and economically diverse sample of 1,400 adolescents (51% female, 56% African American, 39% European American, 5% others). Each aspect of parental involvement contributed differentially but significantly to adolescent outcomes. Finally, parental warmth moderated the associations between providing structure at home and adolescent grade point average and problem behavior.

  5. Prosocial foundations of children's academic achievement.

    PubMed

    Caprara, G V; Barbaranelli, C; Pastorelli, C; Bandura, A; Zimbardo, P G

    2000-07-01

    The present longitudinal research demonstrates robust contributions of early prosocial behavior to children's developmental trajectories in academic and social domains. Both prosocial and aggressive behaviors in early childhood were tested as predictors of academic achievement and peer relations in adolescence 5 years later. Prosocialness included cooperating, helping, sharing, and consoling, and the measure of antisocial aspects included proneness to verbal and physical aggression. Prosocialness had a strong positive impact on later academic achievement and social preferences, but early aggression had no significant effect on either outcome. The conceptual model accounted for 35% of variance in later academic achievement, and 37% of variance in social preferences. Additional analysis revealed that early academic achievement did not contribute to later academic achievement after controlling for effects of early prosocialness. Possible mediating processes by which prosocialness may affect academic achievement and other socially desirable developmental outcomes are proposed.

  6. Academic writing

    NASA Astrophysics Data System (ADS)

    Eremina, Svetlana V.

    2003-10-01

    The series of workshops on academic writing have been developed by academic writing instructors from Language Teaching Centre, Central European University and presented at the Samara Academic Writing Workshops in November 2001. This paper presents only the part dealing with strucutre of an argumentative essay.

  7. F.A.C.E.S. (Faculty Academic Community Education Showcase): Professional Growth Experiences in a Career University

    ERIC Educational Resources Information Center

    Colbert, Paul J.

    2012-01-01

    Institutes of higher education exist for the purpose of developing, fostering, nurturing, and stimulating the intellectual growth and development of students. The core values of a college education provide students conceptual and practical educational opportunities that focus on improving their skills and knowledge. These skills and knowledge…

  8. The fastest evolutionary trajectory

    PubMed Central

    Traulsen, Arne; Iwasa, Yoh; Nowak, Martin A.

    2008-01-01

    Given two mutants, A and B, separated by n mutational steps, what is the evolutionary trajectory which allows a homogeneous population of A to reach B in the shortest time? We show that the optimum evolutionary trajectory (fitness landscape) has the property that the relative fitness increase between any two consecutive steps is constant. Hence, the optimum fitness landscape between A and B is given by an exponential function. Our result is precise for small mutation rates and excluding back mutations. We discuss deviations for large mutation rates and including back mutations. For very large mutation rates, the optimum fitness landscape is flat and has a single peak at type B. PMID:17900629

  9. How Academic Is Academic Development?

    ERIC Educational Resources Information Center

    Fraser, Kym; Ling, Peter

    2014-01-01

    University provision for academic development is well established in the USA, UK and many other countries. However, arrangements for its provision and staffing vary. In Australia, there has been a trend towards professional rather than academic staff appointments. Is this appropriate? In this paper, the domains of academic development work are…

  10. Embryonic developmental plasticity of the chick: increased CO(2) during early stages of incubation changes the developmental trajectories during prenatal and postnatal growth.

    PubMed

    De Smit, Lieve; Bruggeman, Veerle; Tona, Jacob K; Debonne, Marianne; Onagbesan, Okanlawon; Arckens, Lut; De Baerdemaeker, Josse; Decuypere, Eddy

    2006-10-01

    This study investigated the effect of non-ventilation of the incubator during the first 10 days of incubation on carbon dioxide (CO(2)) concentrations in the incubator and its effects on the embryonic and post-hatch development of the chicken (Gallus gallus). Two different incubation conditions were created, one incubator was kept at standard conditions, with adequate ventilation (V) and a second incubator was non-ventilated (NV) during the first ten days of incubation, allowing the CO(2) to rise. After the first 10 days, both incubations were continued under standard conditions. The experiment was repeated twice with different ages of the breeders (45 and 60 wks) which resulted in different CO(2) levels at ED10 (1.5 and 1%). The CO(2) concentration in the V incubators remained below 0.1% in these first 10 days. The eggs of the NV incubation showed higher pCO(2) levels in the air cell from ED10 until ED14 compared to the eggs of the V group. The NV embryos had significantly higher absolute and relative (to egg weight) body weights from ED10 until ED18, pointing to an accelerated embryonic growth. At internal pipping, the NV chick embryos had higher plasma corticosterone and T(3) levels and higher pCO(2) in the air cell. Chicks incubated under NV conditions hatched 10 h earlier in the first and 15 h earlier in the second experiment and the spread of hatch was narrower. During the post-hatch period, the NV chickens had a higher body weight compared to the V chickens. From these results, it is clear that higher levels of CO(2) during the first ten days of incubation have persistent (epigenetic) effects during the incubation and early post-hatch period.

  11. Patched Conic Trajectory Code

    NASA Technical Reports Server (NTRS)

    Park, Brooke Anderson; Wright, Henry

    2012-01-01

    PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semi-major axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory. The patched conic approximation divides the planetary mission into three parts: (1) the departure phase, in which the two relevant bodies are Earth and the spacecraft, and where the trajectory is a departure hyperbola with Earth at the focus; (2) the cruise phase, in which the two bodies are the Sun and the spacecraft, and where the trajectory is a transfer ellipse with the Sun at the focus; and (3) the arrival phase, in which the two bodies are the target planet and the spacecraft, where the trajectory is an arrival hyperbola with the planet as the focus.

  12. Mission objectives and trajectories

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The present state of the knowledge of asteroids was assessed to identify mission and target priorities for planning asteroidal flights in the 1980's and beyond. Mission objectives, mission analysis, trajectory studies, and cost analysis are discussed. A bibliography of reports and technical memoranda is included.

  13. Trajectory structures and transport

    SciTech Connect

    Vlad, Madalina; Spineanu, Florin

    2004-11-01

    The special problem of transport in two-dimensional divergence-free stochastic velocity fields is studied by developing a statistical approach, the nested subensemble method. The nonlinear process of trapping determined by such fields generates trajectory structures whose statistical characteristics are determined. These structures strongly influence the transport.

  14. Infant BMI trajectories are associated with young adult body composition

    PubMed Central

    Slining, M. M.; Herring, A. H.; Popkin, B. M.; Mayer-Davis, E. J.; Adair, L. S.

    2013-01-01

    The dynamic aspect of early life growth is not fully captured by typical analyses, which focus on one specific time period. To better understand how infant and young child growth relate to the development of adult body composition, the authors characterized body mass index (BMI) trajectories using latent class growth analysis (LCGA) and evaluated their association with adult body composition. Data are from the Cebu Longitudinal Health and Nutrition Survey, which followed a birth cohort to age 22 years (n=1749). In both males and females, LCGA identified seven subgroups of respondents with similar BMI trajectories from 0 to 24 months (assessed with bimonthly anthropometrics). Trajectory groups were compared with conventional approaches: (1) accelerated growth between two time points (0–4 months), (2) continuous BMI gain between two points (0–4 months and 0–24 months) and (3) BMI measured at one time point (24 months) as predictors of young adult body composition measures. The seven trajectory groups were distinguished by age-specific differences in tempo and timing of BMI gain in infancy. Infant BMI trajectories were better than accelerated BMI gain between 0 and 4 months at predicting young adult body composition. After controlling for BMI at age 2 years, infant BMI trajectories still explained variation in adult body composition. Using unique longitudinal data and methods, we find that distinct infant BMI trajectories have long-term implications for the development of body composition. PMID:24040489

  15. Beyond the deficit model: bullying and trajectories of character virtues in adolescence.

    PubMed

    Hilliard, Lacey J; Bowers, Edmond P; Greenman, Kathleen N; Hershberg, Rachel M; Geldhof, G John; Glickman, Samantha A; Lerner, Jacqueline V; Lerner, Richard M

    2014-06-01

    Previous work on peer victimization has focused primarily on academic outcomes and negative indicators of youth involved in bullying. Few studies have taken a strength-based approach to examine attributes associated with bullies and victims of bullying. As such, we examined developmental trajectories of moral, performance, and civic character components, and their links to bully status using data from 713 youth (63% female) who participated in Wave 3 (approximately Grade 7) through Wave 6 (approximately Grade 10) of the 4-H Study of Positive Youth Development. Latent growth curve analyses indicated that moral character was stable across waves, whereas civic character increased slightly by Wave 6. Trajectories for performance character varied; some youth alternatively displayed positive versus negative growth. Youth who reported bullying behavior reported lower initial levels of moral, performance, and civic character as compared to youth not involved in bullying. Bully-victims reported lower initial levels of moral and civic character as compared to youth not involved in bullying. Implications for future work examining character-related components in the context of peer victimization are discussed.

  16. Tracing Developmental Trajectories of Oppositional Defiant Behaviors in Preschool Children

    PubMed Central

    Ezpeleta, Lourdes; Granero, Roser; de la Osa, Núria; Navarro, José Blas; Penelo, Eva; Domènech, Josep M.

    2014-01-01

    Objective Previous studies on developmental trajectories have used ad hoc definitions of oppositional defiant behaviors (ODB), which makes it difficult to compare results. This article defines developmental trajectories of ODB from ages 3–5 based on five different standard measurements derived from three separate instruments. Method A sample of 622 three-year-old preschoolers, followed up at ages 4, 5, and 6, was assessed with the five measures of oppositionality answered by parents and teachers. Growth-Mixture-Modeling (GMM) estimated separate developmental trajectories for each ODB measure for ages 3 to 5. Results The number of classes-trajectories obtained in each GMM depended on the ODB measure, but two clear patterns emerged: four trajectories (persistent low, decreasers, increasers/high increasers, persistent moderate/persistent high) or three trajectories (persistent low, decreasers, increasers/high increasers). Persistent high trajectories accounted for 4.4%–9.5% of the children. The trajectories emerging from the different ODB measures at ages 3 to 5 discriminated disruptive disorders, comorbidity, use of services, and impairment at age 6, and globally showed a similar pattern, summarizing longitudinal information on oppositionality in preschool children in a similar way. Conclusions Trajectories resulting from standard scales of the questionnaires have predictive validity for identifying relevant clinical outcomes, but are measure-specific. The results contribute to knowledge about the development of ODB in preschool children. PMID:24972147

  17. TrackTable Trajectory Analysis

    SciTech Connect

    Wilson, Andrew T.

    2014-08-25

    Tracktable is designed for analysis and rendering of the trajectories of moving objects such as planes, trains, automobiles and ships. Its purpose is to operate on large sets of trajectories (millions) to help a user detect, analyze and display patterns. It will also be used to disseminate trajectory research results from Sandia's PANTHER Grand Challenge LDRD.

  18. Teacher-student relationship quality type in elementary grades: Effects on trajectories for achievement and engagement.

    PubMed

    Wu, Jiun-Yu; Hughes, Jan N; Kwok, Oi-Man

    2010-10-01

    Teacher, peer, and student reports of the quality of the teacher-student relationship were obtained for an ethnically diverse and academically at-risk sample of 706 second- and third-grade students. Cluster analysis identified four types of relationships based on the consistency of child reports of support and conflict in the relationship with reports of others: Congruent Positive, Congruent Negative, Incongruent Child Negative, and Incongruent Child Positive. The cluster solution evidenced good internal consistency and construct validity. Group membership predicted growth trajectories for teacher-rated engagement and standardized achievement scores over the following three years, above prior performance. The predictive associations between child reports of teacher support and conflict and the measured outcomes depended on whether child reports were consistent or inconsistent with reports of others. Study findings have implications for theory development, assessment of teacher-student relationships, and teacher professional development.

  19. Trajectory Code Studies, 1987

    SciTech Connect

    Poukey, J.W.

    1988-01-01

    The trajectory code TRAJ has been used extensively to study nonimmersed foilless electron diodes. The basic goal of the research is to design low-emittance injectors for electron linacs and propagation experiments. Systems studied during 1987 include Delphi, Recirc, and Troll. We also discuss a partly successful attempt to extend the same techniques to high currents (tens of kA). 7 refs., 30 figs.

  20. Surrealistic Bohm Trajectories

    NASA Astrophysics Data System (ADS)

    Englert, Berthold-Georg; Scully, Marian O.; Süssmann, Georg; Walther, Herbert

    1992-12-01

    A study of interferometers with one-bit which-way detectors demonstrates that the trajectories, which David Bohm invented in his attempt at a realistic interpretation of quantum mechanics, are in fact surrealistic, because they may be macroscopically at variance with the observed track of the particle. We consider a two-slit interferometer and an incomplete Stern-Gerlach interferometer, and propose an experimentum crucis based on the latter.

  1. Flight Trajectory Control Investigation

    DTIC Science & Technology

    1981-03-01

    control algorithms for four-dimensional guidance of a transport air- craft were investigated for feasibility. Cost function constraints on the ptimal...21 3.1.6 Solution Constraints .... ............. ... 25 3.1.7 Trajectory Generator Review .. ......... .. 25 3.2 OPTIMAl CONTROLLER ALGORITHM...value formulation to a six-degree-of-freedom point mass aircraft with all the structural, maneuver, and mission constraints accounted for by using pelalty

  2. Academic Vulnerability and Resilience during the Transition to High School: The Role of Social Relationships and District Context

    ERIC Educational Resources Information Center

    Langenkamp, Amy G.

    2010-01-01

    The transition to high school is a critical stage in students' academic trajectories and can be especially difficult for middle school students who struggle academically. Starting high school on a low academic track and with low academic performance often leads to dropping out of high school. This study investigates what might protect academically…

  3. Academic Bullies

    ERIC Educational Resources Information Center

    Fogg, Piper

    2008-01-01

    Many professors have been traumatized by academic bullies. Unlike bullies at school, the academic bully plays a more subtle game. Bullies may spread rumors to undermine a colleague's credibility or shut their target out of social conversations. The more aggressive of the species cuss out co-workers, even threatening to get physical. There is…

  4. Trajectory Optimization: OTIS 4

    NASA Technical Reports Server (NTRS)

    Riehl, John P.; Sjauw, Waldy K.; Falck, Robert D.; Paris, Stephen W.

    2010-01-01

    The latest release of the Optimal Trajectories by Implicit Simulation (OTIS4) allows users to simulate and optimize aerospace vehicle trajectories. With OTIS4, one can seamlessly generate optimal trajectories and parametric vehicle designs simultaneously. New features also allow OTIS4 to solve non-aerospace continuous time optimal control problems. The inputs and outputs of OTIS4 have been updated extensively from previous versions. Inputs now make use of objectoriented constructs, including one called a metastring. Metastrings use a greatly improved calculator and common nomenclature to reduce the user s workload. They allow for more flexibility in specifying vehicle physical models, boundary conditions, and path constraints. The OTIS4 calculator supports common mathematical functions, Boolean operations, and conditional statements. This allows users to define their own variables for use as outputs, constraints, or objective functions. The user-defined outputs can directly interface with other programs, such as spreadsheets, plotting packages, and visualization programs. Internally, OTIS4 has more explicit and implicit integration procedures, including high-order collocation methods, the pseudo-spectral method, and several variations of multiple shooting. Users may switch easily between the various methods. Several unique numerical techniques such as automated variable scaling and implicit integration grid refinement, support the integration methods. OTIS4 is also significantly more user friendly than previous versions. The installation process is nearly identical on various platforms, including Microsoft Windows, Apple OS X, and Linux operating systems. Cross-platform scripts also help make the execution of OTIS and post-processing of data easier. OTIS4 is supplied free by NASA and is subject to ITAR (International Traffic in Arms Regulations) restrictions. Users must have a Fortran compiler, and a Python interpreter is highly recommended.

  5. Academic Freedom and Academic Tenure.

    ERIC Educational Resources Information Center

    De George, Richard T.

    2001-01-01

    Asserts that Martin Michaelson's proposal in "Should Untenured as Well as Tenured Faculty Be Guaranteed Academic Freedom? A Few Observations," despite its good intentions, is seriously flawed and if adopted in preference to existing standards will weaken rather than strengthen academic freedom. (EV)

  6. The role of goal structures and peer climate in trajectories of social achievement goals during high school.

    PubMed

    Makara, Kara A; Madjar, Nir

    2015-04-01

    Students' social goals--reasons for engaging in interpersonal relationships with peers--are consequential for students' interactions with their peers at school and for their well-being. Despite the salience of peer relationships during adolescence, research on social goals is generally lacking compared with academic goals, and it is unknown how these social goals develop over time, especially among high school students. The aim of the study was to assess trajectories of students' social goals and to determine how relevant individual and contextual variables predicted initial levels and trajectories of students' social goals. Participants were 9th through 12th grade students (N = 526) attending a U.S. high school. Students filled out surveys of their social goals (social development, social demonstration-approach, and social demonstration-avoidance) 6 times across 2 school years. Nonlinear growth curve analyses and piecewise growth curve analyses were used to assess trajectories of social goals across time. Students' initial levels of social goals differed based on their gender, grade level, prior achievement, and perceptions of classroom goals structures and peer climate. Furthermore, despite substantial stability over time, the shapes of these goal trajectories were predicted by students' gender, grade level, and perceptions of classroom goal structures and peer climate. In particular, students who perceived an increase in performance-avoidance classroom goals maintained higher demonstration social goals and decreased in developmental social goals over time, and students who perceived an increase in positive peer climate decreased in demonstration-avoidance social goals. Implications and directions for future research on social goals are discussed.

  7. The Trajectories of Adolescents' Perceptions of School Climate, Deviant Peer Affiliation, and Behavioral Problems during the Middle School Years

    ERIC Educational Resources Information Center

    Wang, Ming-Te; Dishion, Thomas J.

    2012-01-01

    This longitudinal study examined trajectories of change in adolescents' perceptions of four dimensions of school climate (academic support, behavior management, teacher social support, and peer social support) and the effects of such trajectories on adolescent problem behaviors. We also tested whether school climate moderated the associations…

  8. Trajectories in parallel optics.

    PubMed

    Klapp, Iftach; Sochen, Nir; Mendlovic, David

    2011-10-01

    In our previous work we showed the ability to improve the optical system's matrix condition by optical design, thereby improving its robustness to noise. It was shown that by using singular value decomposition, a target point-spread function (PSF) matrix can be defined for an auxiliary optical system, which works parallel to the original system to achieve such an improvement. In this paper, after briefly introducing the all optics implementation of the auxiliary system, we show a method to decompose the target PSF matrix. This is done through a series of shifted responses of auxiliary optics (named trajectories), where a complicated hardware filter is replaced by postprocessing. This process manipulates the pixel confined PSF response of simple auxiliary optics, which in turn creates an auxiliary system with the required PSF matrix. This method is simulated on two space variant systems and reduces their system condition number from 18,598 to 197 and from 87,640 to 5.75, respectively. We perform a study of the latter result and show significant improvement in image restoration performance, in comparison to a system without auxiliary optics and to other previously suggested hybrid solutions. Image restoration results show that in a range of low signal-to-noise ratio values, the trajectories method gives a significant advantage over alternative approaches. A third space invariant study case is explored only briefly, and we present a significant improvement in the matrix condition number from 1.9160e+013 to 34,526.

  9. Academic Village.

    ERIC Educational Resources Information Center

    Boles, Rebecca

    2001-01-01

    Presents design features of the Renner Middle School (Plano, Texas) where the sprawling suburbs have been kept at bay while creating the atmosphere of an academic village. Photos and a floor plan are provided. (GR)

  10. Academic Libraries

    ERIC Educational Resources Information Center

    Library Journal, 1970

    1970-01-01

    Building data is given for the following academic libraries: (1) Rosary College, River Forest, Illinois; (2) Abilene Christian College, Abilene, Texas; (3) University of California, San Diego, La Jolla, California. (MF)

  11. Periodic billiard trajectories in polygons: generating mechanisms

    NASA Astrophysics Data System (ADS)

    Vorobets, Ya B.; Gal'perin, G. A.; Stepin, Anatolii M.

    1992-06-01

    CONTENTSIntroduction §1. Billiard trajectories in a plane domain §2. Fagnano's problem. Mechanical interpretations of periodic trajectories in triangles §3. An extremal property of billiard trajectories. Birkhoff's theorem. The non-existence of a unified construction of periodic trajectories in obtuse triangles §4. 'Perpendicular' trajectories in obtuse triangles of special shape §5. 'Perpendicular' trajectories in rational polygons and polyhedra §6. Stable trajectories §7. Stable perpendicular trajectories §8. Isolated trajectories §9. Isolated trajectories in acute and obtuse triangles. The bifurcation diagram of isolated trajectories (a 'hang-glider' configuration) §10. The density of F-triangles in a neighbourhood of (0, 0) §11. Generalization of the construction of isolated trajectories in obtuse triangles §12. Stable and unstable billiard trajectories in plane Weyl chambers §13. A criterion for the stability of periodic trajectories in a regular hexagonConclusionReferences

  12. Lessons in Learning: Understanding the Academic Trajectories of ESL Students

    ERIC Educational Resources Information Center

    Canadian Council on Learning, 2008

    2008-01-01

    Canada depends on a steady flow of immigrants to maintain a viable workforce within an aging population. Without immigration, Canada's dependency ratio--the number of employed versus non-employed individuals--would grow dangerously unbalanced. In recent years, most immigrants have come from countries where the spoken language is not English or…

  13. Academic dentistry.

    PubMed

    Rushton, Vivian E; Horner, Keith

    2008-07-01

    Since 1988, thirteen dental schools have provided dental undergraduate programmes within the United Kingdom (UK). In 2006, two new dental schools were created supporting dental education in the community. A further new dental school in Scotland will be accepting students in autumn 2008. In the past 25 years, extensive reorganisation of the NHS has resulted in long-term implications for the training of medical and dental academic staff. The number of academic clinicians is below the minimum viable level and external constraints, combined with a lack of suitable applicants, have led to a moratorium on academic recruitment within some Dental Schools. A detailed review of the historical and associated factors which have led to the problems presently besetting academic dentistry are discussed along with the initiatives introduced in the last 10 years to revitalise the speciality. Also, the present and future outlook for academic dentistry in other countries are discussed. Opinion is divided as to the appropriate setting for the training of undergraduate students between those who support community-based dental education and those who believe dental education should remain within research led dental establishments. External factors are moulding an unsatisfactory situation that is proving increasingly unattractive to the potential dental academic and the case for reform is obvious.

  14. Calculating Trajectories And Orbits

    NASA Technical Reports Server (NTRS)

    Alderson, Daniel J.; Brady, Franklyn H.; Breckheimer, Peter J.; Campbell, James K.; Christensen, Carl S.; Collier, James B.; Ekelund, John E.; Ellis, Jordan; Goltz, Gene L.; Hintz, Gerarld R.; Legerton, Victor N.; Mccreary, Faith A.; Mitchell, Robert T.; Mottinger, Neil A.; Moultrie, Benjamin A.; Moyer, Theodore D.; Rinker, Sheryl L.; Ryne, Mark S.; Stavert, L. Robert; Sunseri, Richard F.

    1989-01-01

    Double-Precision Trajectory Analysis Program, DPTRAJ, and Orbit Determination Program, ODP, developed and improved over years to provide highly reliable and accurate navigation capability for deep-space missions like Voyager. Each collection of programs working together to provide desired computational results. DPTRAJ, ODP, and supporting utility programs capable of handling massive amounts of data and performing various numerical calculations required for solving navigation problems associated with planetary fly-by and lander missions. Used extensively in support of NASA's Voyager project. DPTRAJ-ODP available in two machine versions. UNIVAC version, NPO-15586, written in FORTRAN V, SFTRAN, and ASSEMBLER. VAX/VMS version, NPO-17201, written in FORTRAN V, SFTRAN, PL/1 and ASSEMBLER.

  15. Jettison Engineering Trajectory Tool

    NASA Technical Reports Server (NTRS)

    Zaczek, Mariusz; Walter, Patrick; Pascucci, Joseph; Armstrong, Phyllis; Hallbick, Patricia; Morgan, Randal; Cooney, James

    2013-01-01

    The Jettison Engineering Trajectory Tool (JETT) performs the jettison analysis function for any orbiting asset. It provides a method to compute the relative trajectories between an orbiting asset and any jettisoned item (intentional or unintentional) or sublimating particles generated by fluid dumps to assess whether an object is safe to jettison, or if there is a risk with an item that was inadvertently lost overboard. The main concern is the interaction and possible recontact of the jettisoned object with an asset. This supports the analysis that jettisoned items will safely clear the vehicle, ensuring no collisions. The software will reduce the jettison analysis task from one that could take days to complete to one that can be completed in hours, with an analysis that is more comprehensive than the previous method. It provides the ability to define the jettison operation relative to International Space Station (ISS) structure, and provides 2D and 3D plotting capability to allow an analyst to perform a subjective clearance assessment with ISS structures. The developers followed the SMP to create the code and all supporting documentation. The code makes extensive use of the object-oriented format of Java and, in addition, the Model-View-Controller architecture was used in the organization of the code, allowing each piece to be independent of updates to the other pieces. The model category is for maintaining data entered by the user and generated by the analysis. The view category provides capabilities for data entry and displaying all or a portion of the analysis data in tabular, 2D, and 3D representation. The controller category allows for handling events that affect the model or view(s). The JETT utilizes orbital mechanics with complex algorithms. Since JETT is written in JAVA, it is essentially platform-independent.

  16. The Effect of Distinguished Educators on Academic Gain of Louisiana Academically Unacceptable Schools

    ERIC Educational Resources Information Center

    Scroggins, Ruby C.

    2012-01-01

    The purpose of this study was to examine the degree of academic growth of Academically Unacceptable schools in Louisiana which have been assigned a Distinguished Educator. Distinguished Educators are external change agents who are placed in Academically Unacceptable schools in Louisiana. The data were generated from the Louisiana Department of…

  17. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, T.J.

    1997-05-20

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile. 8 figs.

  18. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, Thomas J.

    1997-01-01

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile.

  19. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David; Dichmann, Donald James; Clark, Pamela E.; Haapala, Amanda; Howell, Kathleen

    2015-01-01

    Numerous Earth-Moon trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many trajectory options can b e considered which have a wide range of transfer duration, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO) geostationary transfer orbits (GTO) and higher energy direct lunar transfer and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory.

  20. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David; Dichmann, Donald J.; Clark, Pamela; Haapala, Amanda; Howell, Kathleen

    2015-01-01

    Numerous Earth-Moon trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many trajectory options can be considered which have a wide range of transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO), geostationary transfer orbits (GTO), and higher energy direct lunar transfers and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory.

  1. Optimal solar sail planetocentric trajectories

    NASA Technical Reports Server (NTRS)

    Sackett, L. L.

    1977-01-01

    The analysis of solar sail planetocentric optimal trajectory problem is described. A computer program was produced to calculate optimal trajectories for a limited performance analysis. A square sail model is included and some consideration is given to a heliogyro sail model. Orbit to a subescape point and orbit to orbit transfer are considered. Trajectories about the four inner planets can be calculated and shadowing, oblateness, and solar motion may be included. Equinoctial orbital elements are used to avoid the classical singularities, and the method of averaging is applied to increase computational speed. Solution of the two-point boundary value problem which arises from the application of optimization theory is accomplished with a Newton procedure. Time optimal trajectories are emphasized, but a penalty function has been considered to prevent trajectories which intersect a planet's surface.

  2. The Language Growth of Spanish-Speaking English Language Learners

    ERIC Educational Resources Information Center

    Rojas, Raul; Iglesias, Aquiles

    2013-01-01

    Although the research literature regarding language growth trajectories is burgeoning, the shape and direction of English Language Learners' (ELLs) language growth trajectories are largely not known. This study used growth curve modeling to determine the shape of ELLs' language growth trajectories across 12,248 oral narrative language samples…

  3. School life and adolescents' self-esteem trajectories.

    PubMed

    Morin, Alexandre J S; Maïano, Christophe; Marsh, Herbert W; Nagengast, Benjamin; Janosz, Michel

    2013-01-01

    This study investigates heterogeneity in adolescents' trajectories of global self-esteem (GSE) and the relations between these trajectories and facets of the interpersonal, organizational, and instructional components of students' school life. Methodologically, this study illustrates the use of growth mixture analyses, and how to obtain proper student-level effects when there are multiple schools, but not enough to support multilevel analyses. This study is based on a 4-year, six-measurement-point, follow-up of 1,008 adolescents (M(age) = 12.6 years, SD = 0.6 at Time 1.) The results show four latent classes presenting elevated, moderate, increasing, and low trajectories defined based on GSE levels and fluctuations. The results show that GSE becomes trait-like as it increases and that school life effects, moderated by gender, played an important role in predicting membership in these trajectories.

  4. Towards a hypothetical learning trajectory for rational number

    NASA Astrophysics Data System (ADS)

    Wright, Vince

    2014-09-01

    A hypothetical learning trajectory Simon ( Journal for Research in Mathematics Education, 26(2), 114-145, 1995) based on Kieren's (1980, 1988, 1993, 1995) sub-constructs for rational number was developed and used as a framework in a year-long design experiment in a New Zealand Middle School. Instructional sequences were designed using the trajectory. Case studies of six 12-13-year-old students provided evidence of their progression through phases of the hypothetical learning trajectory. The patterns of progress for individual students were displayed using visual maps which revealed considerable variability across the sub-constructs and predicted growth within sub-constructs. The findings supported the usefulness of the hypothetical learning trajectory as an instructional tool supported by other forms of pedagogical-content-knowledge. Developmental connections between the sub-constructs were also suggested.

  5. Employment Trajectories Beyond Retirement.

    PubMed

    Burkert, Carola; Hochfellner, Daniela

    2017-01-01

    Within the political and academic debate on working longer, post-retirement employment is discussed as an alternative to maintain older workers in the labor market. Our article enhances this discussion by studying determinants of transitions into post-retirement jobs within differing work environments of birth cohorts 1940-1942. We estimate proportional subhazard models accounting for competing risks using unique German social security data linked to pension accounts. Our findings suggest that individuals' preferences to take up post-retirement jobs are not mutually exclusive. Our study provides evidence that taking up post-retirement jobs is related to seeking financial security, continuity, and work ability, suggesting that public policy has to develop target-oriented support through a public policy mix of different measures aligned to the different peer groups in the labor market.

  6. Trauma and Posttraumatic Stress Symptoms Predict Alcohol and Other Drug Consequence Trajectories in the First Year of College

    PubMed Central

    Read, Jennifer P.; Colder, Craig R.; Merrill, Jennifer E.; Ouimette, Paige; White, Jacquelyn; Swartout, Ashlyn

    2012-01-01

    Objective College matriculation begins a period of transition into adulthood, one that is marked by new freedoms and responsibilities. This transition also is marked by an escalation in heavy drinking and other drug use, and a variety of use-related negative consequences. Trauma and symptoms of posttraumatic stress disorder (PTSD) may affect alcohol and drug problems, and thus may be a point of intervention. Yet no studies have examined trauma, PTSD, and alcohol and drug problem associations during this developmental period. The present study provides such an examination. Method Matriculating college students (N=997) completed surveys in September (T1) and at five subsequent time points (T2-T6) over their first year of college. With latent growth analysis, trajectories of alcohol and drug-related consequences were modeled to examine how trauma (No Criterion A Trauma, Criterion A Only, No PTSD symptoms) and PTSD (partial or full) symptom status predicted these trajectories. Results Results showed substantial risk for alcohol- and other drug-related negative consequences that is conferred by the presence of PTSD at matriculation. Those with both partial and full PTSD started the year with more alcohol and drug consequences. These individuals showed a steeper decrease in consequences in the first semester, which leveled off as the year progressed. Both alcohol and drug consequences remained higher for those in the PTSD group throughout the academic year. Hyper-arousal symptoms showed unique effects on substance consequence trajectories. Risk patterns were consistent for both partial and full PTSD symptom presentations. Trajectories did not vary by gender. Conclusions Interventions that offer support and resources to students entering college with PTSD may help to ameliorate problem substance use and may ultimately facilitate a stronger transition into college and beyond. PMID:22545739

  7. Trajectories of educational expectations from adolescence to young adulthood in Finland.

    PubMed

    Tynkkynen, Lotta; Tolvanen, Asko; Salmela-Aro, Katariina

    2012-11-01

    The purpose of this person-oriented, 5-wave longitudinal study was to examine the trajectories of educational expectations from adolescence to young adulthood in the context of the expectancy-value theory (Eccles et al., 1983). Altogether, 853 (48% female; M age = 16 years) Finnish adolescents reported their educational expectation, 1st in the last year of comprehensive school and 4 times during the following 5 years. Latent class analysis showed that 5 trajectories of educational expectations fit the data best: stable-university (38%), stable-vocational (18%), stable-polytechnic (24%), increasing-expectations (10%), and decreasing-expectations (10%). In line with the expectancy-value theory, adolescents' academic achievement, socioeconomic status (SES), perception of parents' aspirations for them, and ability-beliefs were all related to their trajectories of educational expectations. For example, the higher the adolescent's SES, perception of parents' educational aspirations, and grade point average (GPA), the more likely the participant was to be in the stable-university trajectory compared to the stable-vocational trajectory. Gender had an indirect effect on the trajectories via GPA. Moreover, participants with higher ability-beliefs were more likely to be in trajectories with high and stable educational expectations compared to the unstable trajectories. The trajectories were related to the participants' educational situation after comprehensive school.

  8. Leading Academics.

    ERIC Educational Resources Information Center

    Middlehurst, Robin

    This book aims to increase the level of interest and understanding of leadership within the academic context and to demonstrate the relevance of leadership for contemporary United Kingdom universities. The book considers the concept of leadership and its appropriateness and usefulness for nonprofit professional organizations such as universities,…

  9. Academic Aspirations

    ERIC Educational Resources Information Center

    Durant, Linda

    2013-01-01

    As colleges and universities become even more complex organizations, advancement professionals need to have the skills, experience, and academic credentials to succeed in this ever-changing environment. Advancement leaders need competencies that extend beyond fundraising, alumni relations, and communications and marketing. The author encourages…

  10. Academic Cloning.

    ERIC Educational Resources Information Center

    Sikula, John P.; Sikula, Andrew F.

    1980-01-01

    The authors define "cloning" as an integral feature of all educational systems, citing teaching practices which reward students for closely reproducing the teacher's thoughts and/or behaviors and administrative systems which tend to promote like-minded subordinates. They insist, however, that "academic cloning" is not a totally…

  11. The High-Technology Connection: Academic/Industrial Cooperation for Economic Growth. ASHE-ERIC Higher Education Research Report No. 6.

    ERIC Educational Resources Information Center

    Johnson, Lynn G.

    Cooperative arrangements between academic institutions and industry are examined, with attention to linkages in high technology research and development (R&D), the commercial application of R&D (technology transfer), and the preparation and continuing development of scientific and engineering personnel. Incentives and barriers to campus/corporate…

  12. Inequality from the First Day of School: The Role of Teachers' Academic Intensity and Sense of Responsibility in Moderating the Learning Growth Gap

    ERIC Educational Resources Information Center

    Youn, Minjong

    2016-01-01

    The author used the concepts of academic intensity and sense of responsibility to examine whether children with low school readiness may be moderated by the amount of exposure to learning activities and the attitudes that teachers hold toward these children. Analysis of the Early Childhood Longitudinal Study-Kindergarten Cohort revealed that…

  13. Flight test trajectory control analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1983-01-01

    Recent extensions to optimal control theory applied to meaningful linear models with sufficiently flexible software tools provide powerful techniques for designing flight test trajectory controllers (FTTCs). This report describes the principal steps for systematic development of flight trajectory controllers, which can be summarized as planning, modeling, designing, and validating a trajectory controller. The techniques have been kept as general as possible and should apply to a wide range of problems where quantities must be computed and displayed to a pilot to improve pilot effectiveness and to reduce workload and fatigue. To illustrate the approach, a detailed trajectory guidance law is developed and demonstrated for the F-15 aircraft flying the zoom-and-pushover maneuver.

  14. Galileo's Trajectory with Mild Resistance

    ERIC Educational Resources Information Center

    Groetsch, C. W.

    2012-01-01

    An aspect of Galileo's classical trajectory that persists in a simple resistance model is noted. The resistive model provides a case study for the classroom analysis of limiting behaviour of an implicitly defined function. (Contains 1 note.)

  15. Four-body trajectory optimization

    NASA Technical Reports Server (NTRS)

    Pu, C. L.; Edelbaum, T. N.

    1973-01-01

    A collection of typical three-body trajectories from the L1 libration point on the sun-earth line to the earth is presented. These trajectories in the sun-earth system are grouped into four distinct families which differ in transfer time and delta V requirements. Curves showing the variations of delta V with respect to transfer time, and typical two and three-impulse primer vector histories, are included. The development of a four-body trajectory optimization program to compute fuel optimal trajectories between the earth and a point in the sun-earth-moon system are also discussed. Methods for generating fuel optimal two-impulse trajectories which originate at the earth or a point in space, and fuel optimal three-impulse trajectories between two points in space, are presented. A brief qualitative comparison of these methods is given. An example of a four-body two-impulse transfer from the Li libration point to the earth is included.

  16. Hermes emergency reentry trajectories consequences on the Ariane 5 trajectories

    NASA Astrophysics Data System (ADS)

    Delattre, Ph.; Wagner, A.

    1990-06-01

    Hermes emergency reentry trajectories occur in case of any failure during that part of the launch phase from jettisoning the burn-out solid propellant boosters till the ignition of the MPH. In that case the Crew Escape Module cannot be used because of high Mach numbers and very severe constraints that would result of its low lift coefficient. The maximum constraints on the Hermes space plane are obtained in the atmospheric reentry phase of the emergency trajectories. Their important level is due to the deep flight path angle attained during the ballistic arc of the trajectory. Their values are depending on the instant of launch abort. These maximum constraints are very depending on the launch trajectory. The maximum Hermes constraints were represented in the altitude-velocity plane as a maximum altitude boundary for the Ariane 5 launch trajectory. Unfortunately a performance loss is the result of the requirement for a reduction of the culmination altitude. This has lead to a launch trajectory optimization that will be detailed in this paper. As an out-come of this study two important decisions have been made by CNES: choice of a L6 for the Hermes propulsion module; and the choice of the boundary that constraints the launch trajectory. Important efforts were made on Hermes in order to reduce the maximum constraints, in the field of aerodynamics (moment coefficient reduction, increase of the maximum angle of attack), center of gravity location (in order to reduce control surfaces hinge-moments and temperatures) and elevon-body-flap differential deflection.

  17. The ESA's Space Trajectory Analysis software suite

    NASA Astrophysics Data System (ADS)

    Ortega, Guillermo

    The European Space Agency (ESA) initiated in 2005 an internal activity to develop an open source software suite involving university science departments and research institutions all over the world. This project is called the "Space Trajectory Analysis" or STA. This article describes the birth of STA and its present configuration. One of the STA aims is to promote the exchange of technical ideas, and raise knowledge and competence in the areas of applied mathematics, space engineering, and informatics at University level. Conceived as a research and education tool to support the analysis phase of a space mission, STA is able to visualize a wide range of space trajectories. These include among others ascent, re-entry, descent and landing trajectories, orbits around planets and moons, interplanetary trajectories, rendezvous trajectories, etc. The article explains that STA project is an original idea of the Technical Directorate of ESA. It was born in August 2005 to provide a framework in astrodynamics research at University level. As research and education software applicable to Academia, a number of Universities support this development by joining ESA in leading the development. ESA and Universities partnership are expressed in the STA Steering Board. Together with ESA, each University has a chair in the board whose tasks are develop, control, promote, maintain, and expand the software suite. The article describes that STA provides calculations in the fields of spacecraft tracking, attitude analysis, coverage and visibility analysis, orbit determination, position and velocity of solar system bodies, etc. STA implements the concept of "space scenario" composed of Solar system bodies, spacecraft, ground stations, pads, etc. It is able to propagate the orbit of a spacecraft where orbital propagators are included. STA is able to compute communication links between objects of a scenario (coverage, line of sight), and to represent the trajectory computations and

  18. How Does Premarital Cohabitation Affect Trajectories of Marital Quality?

    ERIC Educational Resources Information Center

    Tach, Laura; Halpern-Meekin, Sarah

    2009-01-01

    We investigate the link between premarital cohabitation and trajectories of subsequent marital quality using random effects growth curve models and repeated measures of marital quality from married women in the NLSY-79 (N = 3,598). We find that premarital cohabitors experience lower quality marital relationships on average, but this is driven by…

  19. Negative Cognitive Style Trajectories in the Transition to Adolescence

    ERIC Educational Resources Information Center

    Mezulis, Amy; Funasaki, Kristyn; Hyde, Janet Shibley

    2011-01-01

    The development of negative cognitive style was examined in a longitudinal study of 366 community youth. Cognitive style and depressive symptoms were evaluated at ages 11, 13, and 15. Latent growth mixture modeling identified three unique trajectory patterns of negative cognitive style. The "normative" group (71% of the sample) displayed the least…

  20. Employment Trajectories: Exploring Gender Differences and Impacts of Drug Use

    ERIC Educational Resources Information Center

    Huang, David Y. C.; Evans, Elizabeth; Hara, Motoaki; Weiss, Robert E.; Hser, Yih-Ing

    2011-01-01

    This study investigated the impact of drug use on employment over 20 years among men and women, utilizing data on 7661 participants in the National Longitudinal Survey of Youth. Growth mixture modeling was applied, and five distinct employment trajectory groups were identified for both men and women. The identified patterns were largely similar…

  1. Classroom Effects on Children's Achievement Trajectories in Elementary School

    ERIC Educational Resources Information Center

    Pianta, Robert C.; Belsky, Jay; Vandergrift, Nathan; Houts, Renate; Morrison, Fred J.

    2008-01-01

    This nonexperimental, longitudinal field study examines the extent to which variation in observed classroom supports (quality of emotional and instructional interactions and amount of exposure to literacy and math activities) predicts trajectories of achievement in reading and math from 54 months to fifth grade. Growth mixture modeling detected…

  2. Trajectories of Internalizing Problems in War-Affected Sierra Leonean Youth: Examining Conflict and Postconflict Factors

    ERIC Educational Resources Information Center

    Betancourt, Theresa S.; McBain, Ryan; Newnham, Elizabeth A.; Brennan, Robert T.

    2013-01-01

    Three waves of data from a prospective longitudinal study in Sierra Leone were used to examine internalizing trajectories in 529 war-affected youth (ages 10-17 at baseline; 25% female). Latent class growth analyses identified 4 trajectories: A large majority of youth maintained lower levels of internalizing problems (41.4%) or significantly…

  3. Developmental Trajectories of Emotional Disengagement from Schoolwork and Their Longitudinal Associations in England

    ERIC Educational Resources Information Center

    Symonds, Jennifer; Schoon, Ingrid; Salmela-Aro, Katariina

    2016-01-01

    This study identified the varied ways in which emotional disengagement from schoolwork typically developed between 14 and 16 years of age, in the Longitudinal Study of Young People in England. Using growth mixture modelling we found eight main trajectories of (dis)engagement, with four trajectories of either increasing or stable emotional…

  4. Trajectories of Developmental Functioning among Children of Adolescent Mothers: Factors Associated with Risk for Delay

    ERIC Educational Resources Information Center

    Jahromi, Laudan B.; Umaña-Taylor, Adriana J.; Updegraff, Kimberly A.; Zeiders, Katharine H.

    2016-01-01

    Children of adolescent mothers are at risk for developmental delays. Less is known about the heterogeneity in these children's developmental trajectories, and factors associated with different patterns of development. This longitudinal study used latent class growth analysis (LCGA) to identify distinct trajectories in children of Mexican-origin…

  5. Trajectories in Operating a Handheld Tool

    ERIC Educational Resources Information Center

    Heuer, Herbert; Sulzenbruck, Sandra

    2009-01-01

    The authors studied the trajectories of the hand and of the tip of a handheld sliding first-order lever in aiming movements. With this kind of tool, straight trajectories of the hand are generally associated with curved trajectories of the tip of the lever and vice versa. Trajectories of the tip of the lever exhibited smaller deviations from…

  6. TAOS. Trajectory Analysis and Optimization System

    SciTech Connect

    Salguero, D.E.

    1995-12-09

    TAOS is a general-purpose software tool capable of analyzing nearly any type of three degree-of-freedom point-mass, high-speed trajectory. Input files contain aerodynamic coefficients, propulsion data, and a trajectory description. The trajectory description divides the trajectory into segments, and within each segment, guidance rules provided by the user describe how the trajectory is computed. Output files contain tabulated trajectory information such as position, velocity, and acceleration. Parametric optimization provides a powerful method for satisfying mission-planning constraints, and trajectories involving more than one vehicle can be computed within a single problem.

  7. English Vocabulary Trajectories of Students Whose Parents Speak a Language Other than English: Steep Trajectories and Sharp Summer Setback

    ERIC Educational Resources Information Center

    Lawrence, Joshua Fahey

    2012-01-01

    In this study, I used individual growth modeling methods to examine the English word-learning trajectories of adolescent students (N = 278) whose parents speak English at home (n = 210) and those whose parents speak a language other than English (n = 68). Sixth- (n = 130) and seventh-grade (n = 148) students attending an urban middle school took…

  8. Physics Academic Workforce Report, 2002. AIP Report.

    ERIC Educational Resources Information Center

    Ivie, Rachel; Stowe, Katie; Nies, Kimberley

    This report discusses trends in the physics academic workforce and the implications of these trends for the future academic job market. Data are from a survey of physics departments that was completed by 722 departments, a response rate of 94%. The number of physics faculty increased almost 5% since 2000, and much of this growth resulted from…

  9. Early Math Trajectories: Low-Income Children's Mathematics Knowledge from Age 4 to 11

    ERIC Educational Resources Information Center

    Rittle-Johnson, Bethany; Fyfe, Emily R.; Hofer, Kerry G.; Farran, Dale C.

    2016-01-01

    Early mathematics knowledge is a strong predictor of later academic achievement, but children from low-income families enter school with weak mathematics knowledge. An Early Math Trajectories model is proposed and evaluated within a longitudinal study of 517 low-income American children from age 4 to 11. This model includes a broad range of math…

  10. Adolescent Behavioral, Emotional, and Cognitive Engagement Trajectories in School and Their Differential Relations to Educational Success

    ERIC Educational Resources Information Center

    Wang, Ming-Te; Eccles, Jacquelynne S.

    2012-01-01

    The current study used a multidimensional approach to examine developmental trajectories of three dimension of school engagement (school participation, sense of school belonging, and self-regulated learning) from grades 7 to 11 and their relationships to changes in adolescents' academic outcomes over time. The sample includes 1,148 African…

  11. Self-Efficacy Beliefs as Shapers of Children's Aspirations and Career Trajectories.

    ERIC Educational Resources Information Center

    Bandura, Albert; Barbaranelli, Claudio; Caprara, Gian Vittorio; Pastorelli, Concetta

    2001-01-01

    Tested a structural model of the network of sociocognitive influences shaping children's career aspirations and trajectories among 272 early adolescents. Found that subjects' perceived efficacy rather than their actual academic achievement was the key determinant of their perceived occupational self-efficacy and preferred choice of worklife.…

  12. Understanding the Gender Gap in School Performance among Low-Income Children: A Developmental Trajectory Analysis

    ERIC Educational Resources Information Center

    Kingdon, Danielle; Serbin, Lisa A.; Stack, Dale M.

    2017-01-01

    Internationally, girls outperform boys in overall school performance. The gender gap is particularly large among those in at-risk groups, such as children from families at economic disadvantage. This study modeled the academic trajectories of a low-income sample of boys and girls from the Concordia Longitudinal Risk Project across the full course…

  13. Global Cultural Capital and Global Positional Competition: International Graduate Students' Transnational Occupational Trajectories

    ERIC Educational Resources Information Center

    Kim, Jongyoung

    2016-01-01

    International graduate students' occupational trajectories have rarely been studied, although many studies exist on their learning experiences in foreign universities. Based on 80 qualitative interviews, this article aims to understand how, where, and why these students obtain jobs in academe and corporations. I focus particularly on Korean…

  14. Early-childhood BMI trajectories: evidence from a prospective, nationally representative British cohort study

    PubMed Central

    Stuart, B; Panico, L

    2016-01-01

    Background and Objectives: By age 5, 20% of British children are classed as overweight or obese, suggesting that early childhood is crucial for lifelong body mass index (BMI) trajectories. In this paper, we identify latent trajectories of early-childhood BMI from ages 3 to 11 years. Given the current context of growing socio-economic inequalities in childhood and adult overweight and obesity, we examine the socio-economic characteristics and mechanisms during pregnancy and infancy which underscore these trajectories. Subject and Methods: We use a nationally representative, prospective cohort study of 9699 children born in 2000–2002, living in the United Kingdom shortly after birth, with complete information on height and weight (measured by an interviewer) at ages 3, 5, 7 and 11. Trajectories of BMI are calculated using latent growth mixture models. Multinomial models characterize these trajectories by their socio-economic profiles and mechanisms during pregnancy and infancy. Results: Four trajectories were identified: two separate trajectories where BMI remains within a normal range (85% of the sample), an overweight trajectory (14.4%), and an obese trajectory (3.1%). No ‘declining BMI' or late-onset groups were found. The obese group is already distinct from the other trajectories by age 3. The overweight group diverges from the normal groups around age 5. Strong socio-economic inequalities emerged; for the obese group, part of this disadvantage is mediated through early mechanisms such as pregnancy smoke and not initiating breastfeeding. Conclusions: This study provides strong evidence for the idea that childhood BMI trajectories develop early, especially for children who will follow an obese trajectory. Strong socio-economic patterns in these trajectories suggest that the observed trend in growing inequalities may be rooted in early life. Mediating mechanisms for the obese appear to be in the pregnancy and infant period, further research should explore

  15. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  16. Trajectories of Failure: The Educational Careers of Children with Mental Health Problems.

    PubMed

    McLeod, Jane D; Fettes, Danielle L

    2007-11-01

    The authors draw on developmental psychopathology, life course sociology, and scholarship on educational processes to develop a conceptual framework for understanding the association of children's mental health problems with educational attainment. They use this framework to address two empirical gaps in prior research: lack of attention to mental health trajectories and the failure to consider diverse explanations. Using data from the Children of the National Longitudinal Surveys of Youth data set, the authors identify latent classes that characterize trajectories of internalizing and externalizing problems from childhood through adolescence. Youths in the classes vary significantly in their likelihoods of high school completion and college entry. The authors evaluate the ability of three sets of mediators to explain these patterns: academic aptitude, disruptive behaviors, and educational expectations. Educational expectations are important mediators independent of academic aptitude and disruptive behaviors. Social responses to youths' mental health problems contribute importantly to their disrupted educational trajectories.

  17. Attachment security to mothers and fathers and the developmental trajectories of depressive symptoms in adolescence: which parent for which trajectory?

    PubMed

    Duchesne, Stéphane; Ratelle, Catherine F

    2014-04-01

    This longitudinal study investigated the links between adolescents' perceptions of attachment security in their relationships with their mothers and fathers and developmental trajectories of depressive symptoms in a community sample of 414 adolescents (45 % males). The participants were followed annually from age 11 (end of elementary school) to 16 (end of high school). Group-based trajectory modeling analyses conditional on risk and protective factors identified four trajectories of depressive symptoms across adolescence: moderate stable (MS; 54.57 % of the sample), low stable (LS; 27.16 %), moderate increasing (MI; 11.30 %), and high declining (HD; 6.97 %). Membership in the HD versus LS trajectory group was predicted by attachment security to both the mother and father at baseline (age 11), whereas attachment security to the mother increased the odds of belonging to the MS and MI groups. These relationships were statistically significant after controlling for gender, anxiety symptoms, and academic competence. The findings are discussed with respect to their contribution to attachment theory and the research on the complementary contributions of mothers and fathers to the prevention of depressive symptomatology during adolescence.

  18. Is Academic Feminism an Oxymoron?

    ERIC Educational Resources Information Center

    Stacey, Judith

    2000-01-01

    Discusses paradoxical challenges to the future of academic feminism, noting the growing conservatism of the surrounding political climate and the academy's increasing dependence on technological and managerial forces. Highlights two paradoxes: the growth of transdisciplinary feminist scholarship has generated greater disciplinary specialization,…

  19. Trajectories of Perceived Social Support Among Low-Income Female Survivors of Hurricane Katrina.

    PubMed

    Lowe, Sarah R

    2015-12-01

    The purpose of this study was to explore trajectories of perceived social support among low-income women who survived Hurricane Katrina, and were surveyed prior to the hurricane and approximately one and four years thereafter (N = 562). Latent class growth analysis provided evidence of four trajectories of perceived support: High Increasing (35.9%), High Decreasing (20.3%), Low Stable (41.1 %), and Low Decreasing (2.7%). Bereavement was significantly predictive of membership in the Low Stable trajectory, relative to the High Increasing and High Decreasing trajectories. Higher psychological distress and indicators of greater social network size, density and closeness were significantly predictive of membership in the Low Decreasing trajectory, relative to the High Increasing and High Decreasing trajectories.

  20. Ion drive performance and trajectories

    NASA Technical Reports Server (NTRS)

    Yen, C. L.

    1978-01-01

    The use of Solar Electric Propulsion (SEP) for the Solar Probe Mission is addressed. The dependence of the payload mass on the site of the SEP and the flight time are described on the basis of preliminary data. The range of hardware expected to be available in the 1980's is summarized. There are several classes of optimal low-thrust trajectories for the Solar Probe Mission. These are trajectory types A, B, C corresponding to one, two, or three orbital revolutions, respectively. Plots of transfer trajectories corresponding to type-A, type-A with a Venus Swingby, type-B, and type-C with ab Icarus Rendezvous are shown. A summary of the SEP performance is given.

  1. Trajectory generation of space telerobots

    NASA Technical Reports Server (NTRS)

    Lumia, R.; Wavering, A. J.

    1989-01-01

    The purpose is to review a variety of trajectory generation techniques which may be applied to space telerobots and to identify problems which need to be addressed in future telerobot motion control systems. As a starting point for the development of motion generation systems for space telerobots, the operation and limitations of traditional path-oriented trajectory generation approaches are discussed. This discussion leads to a description of more advanced techniques which have been demonstrated in research laboratories, and their potential applicability to space telerobots. Examples of this work include systems that incorporate sensory-interactive motion capability and optimal motion planning. Additional considerations which need to be addressed for motion control of a space telerobot are described, such as redundancy resolution and the description and generation of constrained and multi-armed cooperative motions. A task decomposition module for a hierarchical telerobot control system which will serve as a testbed for trajectory generation approaches which address these issues is also discussed briefly.

  2. Personal and Societal Construction of Illness Among Individuals With Rapid-Cycling Bipolar Disorder: A Life-Trajectory Perspective

    PubMed Central

    Sajatovic, Martha; Jenkins, Janis H.; Safavi, Roknedin; West, Jane A.; Cassidy, Kristin A.; Meyer, William J.; Calabrese, Joseph R.

    2011-01-01

    Objective Bipolar disorder is a chronic mental illness associated with substantial impairment in quality of life and function. Although there has been tremendous growth in understanding bipolar disorder with respect to treatments, very little study has focused on the viewpoint of affected individuals. The purpose of this study was to examine the subjective experience of illness among 19 men and women with rapid cycling bipolar disorder receiving treatment at an academic psychiatry clinic. Methods Personal constructs of illness with respect to life-trajectory and societal reaction to the individual, specifically the issue of stigma, were evaluated using a semistructured, open-ended anthropological interview. Results Participants perceived bipolar disorder as a disease with biologic underpinnings. Stigma was a major issue for all individuals. In common with individuals without serious mental illness, individuals with bipolar disorder work at mastering developmental tasks appropriate for their life stage. At times, younger individuals appeared to have difficulty separating their own identity from the effects of illness. For older individuals with bipolar disorder, life was perceived to be disrupted by bipolar disorder, with early plans and dreams often “derailed.” Conclusion Although bipolar disorder may severely alter an individual’s planned life trajectory, accomplishment of life goals can at least partially offset the sense of loss that is often seen in bipolar illness. PMID:18070834

  3. Ballute Aerocapture Trajectories at Neptune

    NASA Technical Reports Server (NTRS)

    Lyons, Daniel T.; Johnson, Wyatt

    2004-01-01

    Using an inflatable ballute system for aerocapture at planets and moons with atmospheres has the potential to provide significant performance benefits compared not only to traditional all propulsive capture, but also to aeroshell based aerocapture technologies. This paper discusses the characteristics of entry trajectories for ballute aerocapture at Neptune. These trajectories are the first steps in a larger systems analysis effort that is underway to characterize and optimize the performance of a ballute aerocapture system for future missions not only at Neptune, but also the other bodies with atmospheres.

  4. Predicting Adult Offenders' Criminal Trajectories from Their Juvenile Criminal Trajectories.

    ERIC Educational Resources Information Center

    Day, David M.; Bevc, Irene; Rosenthal, Jeffrey S.; Duchesne, Thierry; Rossman, Lianne; Theodor, Frances

    This study examined the relationship between adolescent (10-17 years) criminal offending and adult (18-33 years) offending. The sample comprised 378 Canadian male offenders whose criminal trajectory was tracked for an average of 12.1 years, from adolescence into adulthood. Their man age at the time of the most recent follow-up was 27.5 years. The…

  5. Educational trajectories and inequalities of political engagement among adolescents in England.

    PubMed

    Hoskins, Bryony; Janmaat, Jan Germen

    2016-03-01

    Through analysing longitudinal data this article explores the effect of education trajectories between the ages 14-19 on voting and protesting at age 20 taking into account both type of education (vocational/academic) and level of qualifications (Levels 1-3). We find that these trajectories exert an independent effect on both outcomes. Gaining low level qualifications (up to Level 2) and in particular low level vocational qualifications diminishes the chances of political participation relative to Level 3 and academic qualifications. Whilst a wider range of qualifications are conducive to voting, only Level 3 academic qualifications support protesting relative to other qualifications. Post-14 education thus seems to make protesting more of an elite affair. Considering that the vast majority of students in the vocational and lower-level pathways come from low SES families, the undermining influence of these pathways on political participation will be felt disproportionally among the group of socially disadvantaged students.

  6. When Can LEP Students Exit a BE/ESL Program: Predicting Academic Growth Using a Test That Measures Cognitive Language Proficiency.

    ERIC Educational Resources Information Center

    Oakeley, Cecilia; Urrabazo, Theresa; Yang, Hua

    This study looks at predicting the length of time the students in the Dallas Public School District (Texas) will remain in a limited English program. Student growth rates determined from 3 years of data were analyzed and compared to expected growth rates identified by the "Woodcock-Munoz Language Survey (WMLS)." The WMLS annual expected…

  7. Trajectories of internalizing, externalizing, and grades for children who have and have not experienced their parents' divorce or separation.

    PubMed

    Lansford, Jennifer E; Malone, Patrick S; Castellino, Domini R; Dodge, Kenneth A; Pettit, Gregory S; Bates, John E

    2006-06-01

    This study examined whether the occurrence and timing of parental separation or divorce was related to trajectories of academic grades and mother- and teacher-reported internalizing and externalizing problems. The authors used hierarchical linear models to estimate trajectories for children who did and did not experience their parents' divorce or separation in kindergarten through 10th grade (N = 194). A novel approach to analyzing the timing of divorce/separation was adopted, and trajectories were estimated from 1 year prior to the divorce/separation to 3 years after the event. Results suggest that early parental divorce/separation is more negatively related to trajectories of internalizing and externalizing problems than is later divorce/separation, whereas later divorce/separation is more negatively related to grades. One implication of these findings is that children may benefit most from interventions focused on preventing internalizing and externalizing problems, whereas adolescents may benefit most from interventions focused on promoting academic achievement.

  8. Group-based trajectory modeling in clinical research.

    PubMed

    Nagin, Daniel S; Odgers, Candice L

    2010-01-01

    Group-based trajectory models are increasingly being applied in clinical research to map the developmental course of symptoms and assess heterogeneity in response to clinical interventions. In this review, we provide a nontechnical overview of group-based trajectory and growth mixture modeling alongside a sampling of how these models have been applied in clinical research. We discuss the challenges associated with the application of both types of group-based models and propose a set of preliminary guidelines for applied researchers to follow when reporting model results. Future directions in group-based modeling applications are discussed, including the use of trajectory models to facilitate causal inference when random assignment to treatment condition is not possible.

  9. Childhood BMI Trajectories Predicting Cardiovascular Risk in Adolescence

    PubMed Central

    Boyer, Brittany P.; Nelson, Jackie A.; Holub, Shayla C.

    2015-01-01

    Objective The current study compared growth parameters of girls’ and boys’ BMI trajectories from infancy to middle childhood, and evaluated these parameters as predictors of cardiovascular disease (CVD) risk in adolescence. Methods Using 657 children from the NICHD Study of Early Child Care and Youth Development (SECCYD), quadratic growth curve analyses were conducted to establish growth parameters (intercept, slope, quadratic term) for girls and boys from 15 months to age 10 ½. Parameters were compared across gender and evaluated as predictors of a CVD risk index at age 15, controlling for characteristics of the adiposity rebound (AR) including age at which it occurred and children’s BMI at the rebound. Results Boys had more extreme trajectories of growth compared to girls with higher initial BMI at 15 months (intercept), more rapid declines in BMI before the AR (slope), and sharper rebound growth in BMI after the rebound (quadratic term). For boys and girls, higher intercept, slope, and quadratic term values predicted higher CVD risk at age 15, controlling for characteristics of the AR. Conclusions Findings suggest that individuals at risk for developing CVD later in life may be identified before the AR by elevated BMI at 15 months and slow BMI declines. Due to the importance of early intervention in altering lifelong health trajectories, consistent BMI monitoring is essential in identifying high-risk children. PMID:25746172

  10. Predictors and sequelae of trajectories of physical aggression in school-age boys and girls.

    PubMed

    Campbell, Susan B; Spieker, Susan; Vandergrift, Nathan; Belsky, Jay; Burchinal, Margaret

    2010-01-01

    Teacher-rated trajectories of physical aggression in boys and girls from first through sixth grade were examined using data from the NICHD Study of Early Child Care and Youth Development. In separate analyses, four trajectories were identified in boys and three in girls. Higher levels of aggression in both boys and girls were related to greater sociodemographic risk and higher maternal harshness in the preschool years; lower levels of observed maternal sensitivity during early childhood also predicted higher trajectories of aggression among girls. Trajectory groups also differed on a range of social and academic adjustment outcomes in sixth grade, with the most aggressive children and even moderately aggressive children evidencing some difficulties in adjustment. Patterns and levels of aggression in boys and girls are discussed as are their predictors and consequences.

  11. Tracking Identity: Academic Performance and Ethnic Identity among Ecuadorian Immigrant Teenagers in Madrid

    ERIC Educational Resources Information Center

    Lucko, Jennifer

    2011-01-01

    This article examines Ecuadorian students' attempts to contest immigrant stereotypes and redefine their social identities in Madrid, Spain. I argue that academic tracking plays a pivotal role in the trajectory of students' emergent ethnic identity. To illustrate this process, I focus on students who abandon their academic and professional…

  12. Social Competence, Social Support, and Academic Achievement in Minority, Low-Income, Urban Elementary School Children

    ERIC Educational Resources Information Center

    Elias, Maurice J.; Haynes, Norris M.

    2008-01-01

    Despite living in disadvantaged urban communities experiencing social and economic hardships, many children emerge with positive outcomes. Social-emotional competence and social support were hypothesized to have strong influences on academic trajectories during the critical period of academic skill acquisition. Participants were 282 third-grade…

  13. Are Approaches to Learning in Kindergarten Associated with Academic and Social Competence Similarly?

    ERIC Educational Resources Information Center

    Razza, Rachel A.; Martin, Anne; Brooks-Gunn, Jeanne

    2015-01-01

    Background: Approaches to learning (ATL) is a key domain of school readiness with important implications for children's academic trajectories. Interestingly, however, the impact of early ATL on children's social competence has not been examined. Objective: This study examines associations between children's ATL at age 5 and academic achievement…

  14. Distance Education: Educational Trajectory Control

    ERIC Educational Resources Information Center

    Isaev, Andrey; Kravets, Alla; Isaeva, Ludmila; Fomenkov, Sergey

    2013-01-01

    Distance education has become a rather popular form of education recently. The advantages of this form are obvious and well-known. They include asynchronous learning, individualized learning trajectories and convenient case technologies. However, the distance form of education is not able to form the trainee's hands-on experience, especially…

  15. Visiting Vehicle Ground Trajectory Tool

    NASA Technical Reports Server (NTRS)

    Hamm, Dustin

    2013-01-01

    The International Space Station (ISS) Visiting Vehicle Group needed a targeting tool for vehicles that rendezvous with the ISS. The Visiting Vehicle Ground Trajectory targeting tool provides the ability to perform both realtime and planning operations for the Visiting Vehicle Group. This tool provides a highly reconfigurable base, which allows the Visiting Vehicle Group to perform their work. The application is composed of a telemetry processing function, a relative motion function, a targeting function, a vector view, and 2D/3D world map type graphics. The software tool provides the ability to plan a rendezvous trajectory for vehicles that visit the ISS. It models these relative trajectories using planned and realtime data from the vehicle. The tool monitors ongoing rendezvous trajectory relative motion, and ensures visiting vehicles stay within agreed corridors. The software provides the ability to update or re-plan a rendezvous to support contingency operations. Adding new parameters and incorporating them into the system was previously not available on-the-fly. If an unanticipated capability wasn't discovered until the vehicle was flying, there was no way to update things.

  16. Classical Trajectories and Quantum Spectra

    NASA Technical Reports Server (NTRS)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  17. Trajectory optimization using regularized variables

    NASA Technical Reports Server (NTRS)

    Lewallen, J. M.; Szebehely, V.; Tapley, B. D.

    1969-01-01

    Regularized equations for a particular optimal trajectory are compared with unregularized equations with respect to computational characteristics, using perturbation type numerical optimization. In the case of the three dimensional, low thrust, Earth-Jupiter rendezvous, the regularized equations yield a significant reduction in computer time.

  18. Canonical Transformations of Kepler Trajectories

    ERIC Educational Resources Information Center

    Mostowski, Jan

    2010-01-01

    In this paper, canonical transformations generated by constants of motion in the case of the Kepler problem are discussed. It is shown that canonical transformations generated by angular momentum are rotations of the trajectory. Particular attention is paid to canonical transformations generated by the Runge-Lenz vector. It is shown that these…

  19. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two design techniques for linear flight test trajectory controllers (FTTCs) are described: Eigenstructure assignment and the minimum error excitation technique. The two techniques are used to design FTTCs for an F-15 aircraft model for eight different maneuvers at thirty different flight conditions. An evaluation of the FTTCs is presented.

  20. Experimental nonlocal and surreal Bohmian trajectories

    PubMed Central

    Mahler, Dylan H.; Rozema, Lee; Fisher, Kent; Vermeyden, Lydia; Resch, Kevin J.; Wiseman, Howard M.; Steinberg, Aephraim

    2016-01-01

    Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed “surreal” when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality. PMID:26989784

  1. Available Instruments for Analyzing Molecular Dynamics Trajectories

    PubMed Central

    Likhachev, I. V.; Balabaev, N. K.; Galzitskaya, O. V.

    2016-01-01

    Molecular dynamics trajectories are the result of molecular dynamics simulations. Trajectories are sequential snapshots of simulated molecular system which represents atomic coordinates at specific time periods. Based on the definition, in a text format trajectory files are characterized by their simplicity and uselessness. To obtain information from such files, special programs and information processing techniques are applied: from molecular dynamics animation to finding characteristics along the trajectory (versus time). In this review, we describe different programs for processing molecular dynamics trajectories. The performance of these programs, usefulness for analyses of molecular dynamics trajectories, strong and weak aspects are discussed. PMID:27053964

  2. Some Concepts for Target Trajectory Predictions

    DTIC Science & Technology

    1994-03-01

    Threat Acceleration 2-1 3 STATE-BASED PREDICTORS 3-1 CV Trajectory 3-1 CA Trajectory 3-1 CTR Trajectory 3-1 EDTR Trajectory 3-2 Helical Trajectory 3-6...8 CONCLUSIONS 8-1 REFERENCES 9-1 V I I NSWCDD/TR-92/445 I U ILLUSTRATIONS I Figure Pa•e 3-1 Typical EDTR trajectory and asymptote 3-5 6-1 True and...predictors. The new state-based predictors include Constant Turning Rate (CTR), Exponentially Decreasing Turning Rate ( EDTR ), and Helical. The CTR

  3. Trajectories and Predictors of Sexually Aggressive Behaviors during Emerging Adulthood

    PubMed Central

    Thompson, Martie P.; Swartout, Kevin M.; Koss, Mary P.

    2013-01-01

    Objective To assess longitudinal trajectories of college males’ sexually aggressive behaviors and determine time-varying individual- and peer-level risk factors that differentiate men who follow these different paths. Method Our analytic sample consisted of 795 men who participated in a longitudinal study on high-risk behaviors among college students. The sample was surveyed at the end of each of their four years at university on a variety of measures, including sexual aggression (SA) and its hypothesized risk factors (hostile masculinity, number of sexual partners, alcohol misuse, and peer norms). Results Using latent growth mixture modeling, we found four distinct SA trajectories – (1) consistently high, (2) decreasing, (3) increasing, and (4) consistently low. Multinomial logistic regression revealed that hostile masculinity and peer norms positively predicted trajectory membership at times when each trajectory reflected a high level of SA. Conclusions Our study adds to the knowledge base by elucidating the different ways sexually aggressive behaviors change during emerging adulthood and how confluence model-derived factors predict the different trajectories. The finding that changes over time in these risk factors correspond with SA perpetration risk informs prevention programming by illuminating the importance of continual focus on these risk factors throughout the college years, perhaps through annual self-assessments. PMID:23914305

  4. Flight trajectory simulation of fluid payload projectiles

    NASA Astrophysics Data System (ADS)

    Vaughn, H. R.; Wolfe, W. P.; Oberkampf, W. L.

    A flight trajectory simulation method has been developed for calculating the six degree-of-freedom motion of fluid filled projectiles. Numerically calculated internal fluid moments and experimentally known aerodynamic forces and moments are coupled to the projectile motion. Comparisons of predicted results with flight test data of an M483 155mm artillery projectile with a highly viscous payload confirm the accuracy of the simulation. This simulation clearly shows that the flight instability is due to the growth of the nutation component of angular motion caused by the viscous effects of the fluid payload. This simulation procedure, when used in conjunction with the previously developed method for calculating internal fluid moments, allows the designer to examine the effects of various liquid payloads and container geometries on the dynamic behavior of flight vehicles.

  5. Developmental Trajectories in Primary Schoolchildren Using n-Back Task

    PubMed Central

    López-Vicente, Mónica; Forns, Joan; Suades-González, Elisabet; Esnaola, Mikel; García-Esteban, Raquel; Álvarez-Pedrerol, Mar; Júlvez, Jordi; Burgaleta, Miguel; Sebastián-Gallés, Núria; Sunyer, Jordi

    2016-01-01

    Background: Neuropsychological instruments to assess cognitive trajectories during childhood in epidemiological studies are needed. This would improve neurodevelopment characterization in order to identify its potential determinants. We aimed to study whether repeated measures of n-back, a working memory task, detect developmental trajectories in schoolchildren during a 1-year follow-up. Methods: We administered the n-back task to 2897 healthy children aged 7–11 years old from 39 schools in Barcelona (Spain). The task consisted of 2 levels of complexity or loads (2- and 3-back) and 2 different stimuli (numbers and words). Participants performed the task four times from January 2012 to March 2013. To study the trajectories during the follow-up, we performed linear mixed-effects models including school, individual and age as random effects. Results: We observed improvements related to age in n-back outcomes d′, HRT and accuracy, as well as reduced cognitive growth at older ages in d′ and HRT. Greater improvements in performance were observed at younger ages, in 2-back, in verbal rather than numerical stimuli and in girls compared to boys. Boys responded faster at baseline, while girls showed increased growth in 2-back numbers. Children with ADHD (Attention Deficit and Hyperactivity Disorder) symptoms (15% of boys and 6% of girls) had a lower working memory at baseline, but they showed similar cognitive growth trajectories in numbers variants of the task, as compared to children without ADHD symptoms. However, the age-related improvement in response speed was not observed in children with ADHD symptoms. Conclusions: Changes in n-back outcomes reflected developmental trajectories in 1-year follow-up. The present results suggest that the repeated administration of this task can be used to study the factors that may alter the cognitive development during childhood. PMID:27242625

  6. A Study of the Trajectories of Projectiles.

    ERIC Educational Resources Information Center

    Grant, A. Ruari

    1990-01-01

    Described is a procedure for studying the trajectories of projectiles using ball bearings and aluminum foil. Trajectories were measured with and without the effects of air resistance. Multiflash photography was used to determine the flight paths of all objects. (KR)

  7. Trajectory Synthesis for Fisher Information Maximization

    PubMed Central

    Wilson, Andrew D.; Schultz, Jarvis A.; Murphey, Todd D.

    2015-01-01

    Estimation of model parameters in a dynamic system can be significantly improved with the choice of experimental trajectory. For general nonlinear dynamic systems, finding globally “best” trajectories is typically not feasible; however, given an initial estimate of the model parameters and an initial trajectory, we present a continuous-time optimization method that produces a locally optimal trajectory for parameter estimation in the presence of measurement noise. The optimization algorithm is formulated to find system trajectories that improve a norm on the Fisher information matrix (FIM). A double-pendulum cart apparatus is used to numerically and experimentally validate this technique. In simulation, the optimized trajectory increases the minimum eigenvalue of the FIM by three orders of magnitude, compared with the initial trajectory. Experimental results show that this optimized trajectory translates to an order-of-magnitude improvement in the parameter estimate error in practice. PMID:25598763

  8. The Trajectory Synthesizer Generalized Profile Interface

    NASA Technical Reports Server (NTRS)

    Lee, Alan G.; Bouyssounouse, Xavier; Murphy, James R.

    2010-01-01

    The Trajectory Synthesizer is a software program that generates aircraft predictions for Air Traffic Management decision support tools. The Trajectory Synthesizer being used by researchers at NASA Ames Research Center was restricted in the number of trajectory types that could be generated. This limitation was not sufficient to support the rapidly changing Air Traffic Management research requirements. The Generalized Profile Interface was developed to address this issue. It provides a flexible approach to describe the constraints applied to trajectory generation and may provide a method for interoperability between trajectory generators. It also supports the request and generation of new types of trajectory profiles not possible with the previous interface to the Trajectory Synthesizer. Other enhancements allow the Trajectory Synthesizer to meet the current and future needs of Air Traffic Management research.

  9. Trajectories of Autism Severity in Early Childhood

    ERIC Educational Resources Information Center

    Venker, Courtney E.; Ray-Subramanian, Corey E.; Bolt, Daniel M.; Weismer, Susan Ellis

    2014-01-01

    Relatively little is known about trajectories of autism severity using calibrated severity scores (CSS) from the Autism Diagnostic Observation Schedule, but characterizing these trajectories has important theoretical and clinical implications. This study examined CSS trajectories during early childhood. Participants were 129 children with autism…

  10. Academic detailing.

    PubMed

    Shankar, P R; Jha, N; Piryani, R M; Bajracharya, O; Shrestha, R; Thapa, H S

    2010-01-01

    There are a number of sources available to prescribers to stay up to date about medicines. Prescribers in rural areas in developing countries however, may not able to access some of them. Interventions to improve prescribing can be educational, managerial, and regulatory or use a mix of strategies. Detailing by the pharmaceutical industry is widespread. Academic detailing (AD) has been classically seen as a form of continuing medical education in which a trained health professional such as a physician or pharmacist visits physicians in their offices to provide evidence-based information. Face-to-face sessions, preferably on an individual basis, clear educational and behavioural objectives, establishing credibility with respect to objectivity, stimulating physician interaction, use of concise graphic educational materials, highlighting key messages, and when possible, providing positive reinforcement of improved practices in follow-up visits can increase success of AD initiatives. AD is common in developed countries and certain examples have been cited in this review. In developing countries the authors have come across reports of AD in Pakistan, Sudan, Argentina and Uruguay, Bihar state in India, Zambia, Cuba, Indonesia and Mexico. AD had a consistent, small but potentially significant impact on prescribing practices. AD has much less resources at its command compared to the efforts by the industry. Steps have to be taken to formally start AD in Nepal and there may be specific hindering factors similar to those in other developing nations.

  11. Geometric diffusion of quantum trajectories

    PubMed Central

    Yang, Fan; Liu, Ren-Bao

    2015-01-01

    A quantum object can acquire a geometric phase (such as Berry phases and Aharonov–Bohm phases) when evolving along a path in a parameter space with non-trivial gauge structures. Inherent to quantum evolutions of wavepackets, quantum diffusion occurs along quantum trajectories. Here we show that quantum diffusion can also be geometric as characterized by the imaginary part of a geometric phase. The geometric quantum diffusion results from interference between different instantaneous eigenstate pathways which have different geometric phases during the adiabatic evolution. As a specific example, we study the quantum trajectories of optically excited electron-hole pairs in time-reversal symmetric insulators, driven by an elliptically polarized terahertz field. The imaginary geometric phase manifests itself as elliptical polarization in the terahertz sideband generation. The geometric quantum diffusion adds a new dimension to geometric phases and may have applications in many fields of physics, e.g., transport in topological insulators and novel electro-optical effects. PMID:26178745

  12. Trajectory correction propulsion for TOPS

    NASA Technical Reports Server (NTRS)

    Long, H. R.; Bjorklund, R. A.

    1972-01-01

    A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

  13. Hierarchical Control and Trajectory Planning

    NASA Technical Reports Server (NTRS)

    Martin, Clyde F.; Horn, P. W.

    1994-01-01

    Most of the time on this project was spent on the trajectory planning problem. The construction is equivalent to the classical spline construction in the case that the system matrix is nilpotent. If the dimension of the system is n then the spline of degree 2n-1 is constructed. This gives a new approach to the construction of splines that is more efficient than the usual construction and at the same time allows the construction of a much larger class of splines. All known classes of splines are reconstructed using the approach of linear control theory. As a numerical analysis tool control theory gives a very good tool for constructing splines. However, for the purposes of trajectory planning it is quite another story. Enclosed in this document are four reports done under this grant.

  14. EPOXI Trajectory and Maneuver Analyses

    NASA Technical Reports Server (NTRS)

    Chung, Min-Kun J.; Bhaskaran, Shyamkumar; Chesley, Steven R.; Halsell, C. Allen; Helfrich, Clifford E.; Jefferson, David C.; McElrath, Timothy P.; Rush, Brian P.; Wang, Tseng-Chan M.; Yen, Chen-wan L.

    2011-01-01

    The EPOXI mission is a NASA Discovery Mission of Opportunity combining two separate investigations: Extrasolar Planet Observation and Characterization (EPOCh) and Deep Impact eXtended Investigation (DIXI). Both investigations reused the DI instruments and spacecraft that successfully flew by the comet Tempel-1 (4 July 2005). For EPOCh, the goal was to find exoplanets with the high resolution imager, while for DIXI it was to fly by the comet Hartley 2 (4 Nov 2010). This paper documents the navigation experience of the earlier ma-neuver analyses critical for the EPOXI mission including statistical ?V analyses and other useful analyses in designing maneuvers. It also recounts the trajectory design leading up to the final reference trajectory to Hartley 2.

  15. Trajectory structures in turbulent plasmas

    SciTech Connect

    Vlad, Madalina; Spineanu, Florin

    2006-11-03

    Particle stochastic advection in two dimensional divergence free velocity fields is studied. The special statistical properties of this process (non-Gaussian distribution, memory effects and quasi-coherent behavior) are determined using a new approach, the nested subensemble method. The effect of the statistics of trajectories on the evolution of drift turbulence in magnetized plasmas is studied. It essentialy consists in the tendency of structure formation.

  16. Fractional Trajectories: Decorrelation Versus Friction

    DTIC Science & Technology

    2013-07-27

    from the integration of fractional differential equations in time. In Section 2 we provide a general demonstration of the new perspective on fractional ...section we demonstrate the equivalence between a fractional trajectory that is the solution of a Caputo fractional differential equation , and the... fractional differential equation dα dtα V(t) = OV(t), (1) where 0 < α < 1 and O is an operator, either linear or nonlinear, acting on the vector V(t

  17. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

  18. Dynamic Scaling of Manipulator Trajectories.

    DTIC Science & Technology

    1983-01-01

    Manipulators Robotics Trajectory Planning Manipulator Dynamics 20. ABSTRACT (Conftnue wn reverse side ID neceeOor Oine Identlfy b? block nuemNer) A...receives a c factor for each b(i). ’lhus both terms change equally with differing movement speeds. This contradicts the normal assumption in the robotics ...as well since they share the same significance as the velocity terms, yet this is not done. In any case, future generations of robots will contain

  19. Bohmian trajectories of Airy packets

    SciTech Connect

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-15

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space–time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject’s theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  20. Trajectory versus probability density entropy.

    PubMed

    Bologna, M; Grigolini, P; Karagiorgis, M; Rosa, A

    2001-07-01

    We show that the widely accepted conviction that a connection can be established between the probability density entropy and the Kolmogorov-Sinai (KS) entropy is questionable. We adopt the definition of density entropy as a functional of a distribution density whose time evolution is determined by a transport equation, conceived as the only prescription to use for the calculation. Although the transport equation is built up for the purpose of affording a picture equivalent to that stemming from trajectory dynamics, no direct use of trajectory time evolution is allowed, once the transport equation is defined. With this definition in mind we prove that the detection of a time regime of increase of the density entropy with a rate identical to the KS entropy is possible only in a limited number of cases. The proposals made by some authors to establish a connection between the two entropies in general, violate our definition of density entropy and imply the concept of trajectory, which is foreign to that of density entropy.

  1. Perching aerodynamics and trajectory optimization

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim

    2007-04-01

    Advances in smart materials, actuators, and control architecture have enabled new flight capabilities for aircraft. Perching is one such capability, described as a vertical landing maneuver using in-flight shape reconfiguration in lieu of high thrust generation. A morphing, perching aircraft design is presented that is capable of post stall flight and very slow landing on a vertical platform. A comprehensive model of the aircraft's aerodynamics, with special regard to nonlinear affects such as flow separation and dynamic stall, is discussed. Trajectory optimization using nonlinear programming techniques is employed to show the effects that morphing and nonlinear aerodynamics have on the maneuver. These effects are shown to decrease the initial height and distance required to initiate the maneuver, reduce the bounds on the trajectory, and decrease the required thrust for the maneuver. Perching trajectories comparing morphing versus fixed-configuration and stalled versus un-stalled aircraft are presented. It is demonstrated that a vertical landing is possible in the absence of high thrust if post-stall flight capabilities and vehicle reconfiguration are utilized.

  2. Collaboration in Academic R&D: A Decade of Growth in Pass-Through Funding. InfoBrief. NSF 12-325

    ERIC Educational Resources Information Center

    Hale, Katherine

    2012-01-01

    Research collaboration involving multiple institutions is a growing trend. Contributing to this growth are federal initiatives as well as practical considerations, such as technological advances that facilitate communication and opportunities for division of labor, risk sharing, and increased research credibility. One measure of this research…

  3. How Do You Measure Success? Academic Wholism Bridges the Gap between High School and College

    ERIC Educational Resources Information Center

    Giuliano, Barbara A.; Sullivan, Judith L.

    2004-01-01

    We conducted a research case study to ascertain the effect of a bridge program on fostering self-growth and academic readiness for college. Academic wholism provided the vehicle to promote self-awareness, self-motivation, and academic maturity. The rippling effect of this program extended beyond academics to the personal level. (Contains 2…

  4. Designing Asteroid Impact Scenario Trajectories

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact

  5. Parental Involvement and African American and European American Adolescents' Academic, Behavioral, and Emotional Development in Secondary School

    ERIC Educational Resources Information Center

    Wang, Ming-Te; Hill, Nancy E.; Hofkens, Tara

    2014-01-01

    This study examined longitudinal trajectories of parental involvement across middle and high school, and how these trajectories related to adolescents' academic, behavioral, and emotional adjustment. In addition, ethnic and socioeconomic status differences in longitudinal associations and the potential moderating role of parental warmth were…

  6. Optimal Output Trajectory Redesign for Invertible Systems

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh

    1996-01-01

    Given a desired output trajectory, inversion-based techniques find input-state trajectories required to exactly track the output. These inversion-based techniques have been successfully applied to the endpoint tracking control of multi-joint flexible manipulators and to aircraft control. The specified output trajectory uniquely determines the required input and state trajectories that are found through inversion. These input-state trajectories exactly track the desired output; however, they might not meet acceptable performance requirements. For example, during slewing maneuvers of flexible structures, the structural deformations, which depend on the required state trajectories, may be unacceptably large. Further, the required inputs might cause actuator saturation during an exact tracking maneuver for example, in the flight control of conventional takeoff and landing aircraft. In such situations, a compromise is desired between the tracking requirement and other goals such as reduction of internal vibrations and prevention of actuator saturation; the desired output trajectory needs to be redesigned.

  7. Rapid Design of Gravity Assist Trajectories

    NASA Technical Reports Server (NTRS)

    Carrico, J.; Hooper, H. L.; Roszman, L.; Gramling, C.

    1991-01-01

    Several International Solar Terrestrial Physics (ISTP) missions require the design of complex gravity assisted trajectories in order to investigate the interaction of the solar wind with the Earth's magnetic field. These trajectories present a formidable trajectory design and optimization problem. The philosophy and methodology that enable an analyst to design and analyse such trajectories are discussed. The so called 'floating end point' targeting, which allows the inherently nonlinear multiple body problem to be solved with simple linear techniques, is described. The combination of floating end point targeting with analytic approximations with a Newton method targeter to achieve trajectory design goals quickly, even for the very sensitive double lunar swingby trajectories used by the ISTP missions, is demonstrated. A multiconic orbit integration scheme allows fast and accurate orbit propagation. A prototype software tool, Swingby, built for trajectory design and launch window analysis, is described.

  8. Emergent patterns of risk for psychopathology: The influence of infant avoidance and maternal caregiving on trajectories of social reticence.

    PubMed

    Degnan, Kathryn A; Hane, Amie Ashley; Henderson, Heather A; Walker, Olga L; Ghera, Melissa M; Fox, Nathan A

    2015-11-01

    The current study investigated the influential role of infant avoidance on links between maternal caregiving behavior and trajectories at risk for psychopathology. A sample of 153 children, selected for temperamental reactivity to novelty, was followed from infancy through early childhood. At 9 months, infant avoidance of fear-eliciting stimuli in the laboratory and maternal sensitivity at home were assessed. At 36 months, maternal gentle discipline was assessed at home. Children were repeatedly observed in the lab with an unfamiliar peer across early childhood. A latent class growth analysis yielded three longitudinal risk trajectories of social reticence behavior: a high-stable trajectory, a high-decreasing trajectory, and a low-increasing trajectory. For infants displaying greater avoidance, 9-month maternal sensitivity and 36-month maternal gentle discipline were both positively associated with membership in the high-stable social reticence trajectory, compared to the high-decreasing social reticence trajectory. For infants displaying lower avoidance, maternal sensitivity was positively associated with membership in the high-decreasing social reticence trajectory, compared to the low-increasing trajectory. Maternal sensitivity was positively associated with the high-stable social reticence trajectory when maternal gentle discipline was lower. These results illustrate the complex interplay of infant and maternal behavior in early childhood trajectories at risk for emerging psychopathology.

  9. Two Paths Diverged: Exploring Trajectories, Protocols, and Dynamic Phases

    NASA Astrophysics Data System (ADS)

    Gingrich, Todd Robert

    -dimensional state space, the trajectory space may also be analytically studied using methods of large deviation theory. We review these methods and introduce a simple class of dynamical models whose dynamical fluctuations we compute exactly. The simplest such model is an asymmetric random walker on a one-dimensional ring with a single heterogeneous link connecting two sites of the ring. We derive conditions for the existence of a dynamic phase transition, which separates two dynamical phases---one localized and the other delocalized. The presence of distinct classes trajectories results in profoundly non-Gaussian fluctuations in dynamical quantities. We discuss the implications of such large dynamical fluctuations in the context of simple stochastic models for biological growth.

  10. Trajectories of Quality of Life among Chinese Patients Diagnosed with Nasopharynegeal Cancer

    PubMed Central

    Lam, Wendy W. T.; Ye, Michelle; Fielding, Richard

    2012-01-01

    Objective This secondary longitudinal analysis describes distinct quality of life trajectories during eight months of radiation therapy (RT) among patients with nasopharyngeal cancer (NPC) and examines factors differentiating these trajectories. Methods 253 Chinese patients with NPC scheduled for RT were assessed at pre-treatment, and 4 months and 8 months later on QoL (Chinese version of the FACT-G), optimism, pain, eating function, and patient satisfaction. Latent growth mixture modelling identified different trajectories within each of four QoL domains: Physical, Emotional, Social/family, and Functional well-being. Multinomial logistic regression compared optimism, pain, eating function, and patient satisfaction by trajectories adjusted for demographic and medical characteristics. Results We identified three distinct trajectories for physical and emotional QoL domains, four trajectories for social/family, and two trajectories for functional domains. Within each domain most patients (physical (77%), emotional (85%), social/family (55%) and functional (63%)) experienced relatively stable high levels of well-being over the 8-month period. Different Physical trajectory patterns were predicted by pain and optimism, whereas for Emotion-domain trajectories pain, optimism, eating enjoyment, patient satisfaction with information, and gender were predictive. Age, appetite, optimism, martial status, and household income predicted Social/family trajectories; household income, eating enjoyment, optimism, and patient satisfaction with information predicted Functional trajectories. Conclusion Most patients with NPC showed high stable QoL during radiotherapy. Optimism predicted good QoL. Symptom impacts varied by QoL domain. Information satisfaction was protective in emotional and functional well-being, reflecting the importance in helping patients to establish a realistic expectation of treatment impacts. PMID:23028484

  11. Trajectories of Delinquent Behaviour in Adolescence and Their Covariates: Relations with Initial and Time-Averaged Factors

    ERIC Educational Resources Information Center

    Wiesner, Margit; Silbereisen, Rainer K.

    2003-01-01

    This longitudinal study examined individual, family, and peer covariates of distinctive trajectories of juvenile delinquency, using data from a community sample of 318 German adolescents (mean age at the first wave was 11.45 years). Latent growth mixture modelling analysis revealed four trajectory groups: high-level offenders, medium-level…

  12. Group-Based Modeling of Time Spent in Structured Activity Trajectories from Middle Childhood into Early Adolescence

    ERIC Educational Resources Information Center

    Mata, Andrea D.; van Dulmen, Manfred H. M.

    2012-01-01

    This study investigated trajectories of time spent in structured activities from middle childhood to early adolescence by using data from the National Institute of Child Health & Human Development (NICHD) Study of Early Child Care. We used latent class growth analyses and identified five trajectories (stable low, increasing high, decreasing low,…

  13. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David C.; Dichman, Don; Clark, Pamela; Haapala, Amanda; Howell, Kathleen

    2014-01-01

    Contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these designs can be restricted by the selection of the Cubesat subsystem design such as propulsion or communication. Nonetheless, many trajectory options can be designed with have a wide range of transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several design options including deployment into low Earth orbit (LEO), geostationary transfer orbits (GTO), and higher energy direct lunar transfer orbits. In addition to direct transfer options from these initial orbits, we also investigate the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory. In this article we examine several design options that meet the above limited deployment and subsystem drivers. We study ways that both impulsive and low-thrust Solar Electric Propulsion (SEP) engines can be used to place the Cubesat first into a highly eccentric Earth orbit, enter the Moon's Sphere of Influence, and finally achieve a highly eccentric lunar orbit. We show that such low-thrust transfers are feasible with a realistic micro-thruster model, assuming that the Cubesat can generate sufficient power for the SEP. Two examples are shown here: (1) A Cubestat injected by Exploration Mission 1 (EM-1) then employing low thrust; and (2) a CubSat deployed in a GTO, then employing impulsive maneuvers. For the EM-1 injected initial design, we increase the EM-1 targeted lunar flyby distance to reduce the energy of the lunar flyby to match that of a typical lMoon system heteroclinic manifold. Figure 1 presents an option that encompasses the similar dynamics as that of the ARTEMIS

  14. Quantum Tunneling and Complex Trajectories

    NASA Astrophysics Data System (ADS)

    Meynig, Max; Haggard, Hal

    2017-01-01

    In general, the semiclassical approximation of quantum mechanical tunneling fails to treat tunneling through barriers if real initial conditions and trajectories are used. By analytically continuing classical dynamics to the complex plane the problems encountered in the approximation can be resolved. While, the complex methods discussed here have been previously explored, no one has exhibited an analytically solvable case. The essential features of the complex method will be discussed in the context of a novel, analytically solvable problem. These methods could be useful in quantum gravity, with applications to the tunneling of spacetime geometries.

  15. Trajectory constraints in qualitative simulation

    SciTech Connect

    Brajnik, G.; Clancy, D.J.

    1996-12-31

    We present a method for specifying temporal constraints on trajectories of dynamical systems and enforcing them during qualitative simulation. This capability can be used to focus a simulation, simulate non-autonomous and piecewise-continuous systems, reason about boundary condition problems and incorporate observations into the simulation. The method has been implemented in TeQSIM, a qualitative simulator that combines the expressive power of qualitative differential equations with temporal logic. It interleaves temporal logic model checking with the simulation to constrain and refine the resulting predicted behaviors and to inject discontinuous changes into the simulation.

  16. Rocket Launch Trajectory Simulations Mechanism

    NASA Technical Reports Server (NTRS)

    Margasahayam, Ravi; Caimi, Raoul E.; Hauss, Sharon; Voska, N. (Technical Monitor)

    2002-01-01

    The design and development of a Trajectory Simulation Mechanism (TSM) for the Launch Systems Testbed (LST) is outlined. In addition to being one-of-a-kind facility in the world, TSM serves as a platform to study the interaction of rocket launch-induced environments and subsequent dynamic effects on the equipment and structures in the close vicinity of the launch pad. For the first time, researchers and academicians alike will be able to perform tests in a laboratory environment and assess the impact of vibroacoustic behavior of structures in a moving rocket scenario on ground equipment, launch vehicle, and its valuable payload or spacecraft.

  17. Driving trajectories in chaotic scattering.

    PubMed

    Macau, Elbert E N; Caldas, Iberê L

    2002-02-01

    In this work we introduce a general approach for targeting in chaotic scattering that can be used to find a transfer trajectory between any two points located inside the scattering region. We show that this method can be used in association with a control of chaos strategy to drive around and keep a particle inside the scattering region. As an illustration of how powerful this approach is, we use it in a case of practical interest in celestial mechanics in which it is desired to control the evolution of two satellites that evolve around a large central body.

  18. Self-efficacy beliefs as shapers of children's aspirations and career trajectories.

    PubMed

    Bandura, A; Barbaranelli, C; Caprara, G V; Pastorelli, C

    2001-01-01

    This prospective study tested with 272 children a structural model of the network of sociocognitive influences that shape children's career aspirations and trajectories. Familial socioeconomic status is linked to children's career trajectories only indirectly through its effects on parents' perceived efficacy and academic aspirations. The impact of parental self-efficacy and aspirations on their children's perceived career efficacy and choice is, in turn, entirely mediated through the children's perceived efficacy and academic aspirations. Children's perceived academic, social, and self-regulatory efficacy influence the types of occupational activities for which they judge themselves to be efficacious both directly and through their impact on academic aspirations. Perceived occupational self-efficacy gives direction to the kinds of career pursuits children seriously consider for their life's work and those they disfavor. Children's perceived efficacy rather than their actual academic achievement is the key determinant of their perceived occupational self-efficacy and preferred choice of worklife. Analyses of gender differences reveal that perceived occupational self-efficacy predicts traditionality of career choice.

  19. Trajectories of depressive symptoms after hip fracture

    PubMed Central

    Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.

    2016-01-01

    Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed ‘resilient’, ‘distressed’, and ‘depressed’. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698

  20. Trajectories of premorbid childhood and adolescent functioning in schizophrenia-spectrum psychoses: A first-episode study

    PubMed Central

    Horton, Leslie E.; Tarbox, Sarah I.; Olino, Thomas M.

    2015-01-01

    Evidence of social and behavioral problems preceding the onset of schizophrenia-spectrum psychoses is consistent with a neurodevelopmental model of these disorders. Here we predict that individuals with a first episode of schizophrenia-spectrum psychoses will evidence one of three patterns of premorbid adjustment: an early deficit, a deteriorating pattern, or adequate or good social adjustment. Participants were 164 (38% female; 31% black) individuals ages 15–50 with a first episode of schizophrenia-spectrum psychoses. Premorbid adjustment was assessed using the Cannon-Spoor Premorbid Adjustment Scale. We compared the fit of a series of growth mixture models to examine premorbid adjustment trajectories, and found the following 3-class model provided the best fit with: a “stable-poor” adjustment class (54%), a “stable-good” adjustment class (39%), and a “deteriorating” adjustment class (7%). Relative to the “stable-good” class, the “stable-poor” class experienced worse negative symptoms at 1-year follow-up, particularly in the social amotivation domain. This represents the first known growth mixture modeling study to examine premorbid functioning patterns in first-episode schizophrenia-spectrum psychoses. Given that the stable-poor adjustment pattern was most prevalent, detection of social and academic maladjustment as early as childhood may help identify people at increased risk for schizophrenia-spectrum psychoses, potentially increasing feasibility of early interventions. PMID:25829134

  1. A Critical Review of the Canadian Empirical Literature: Documenting Generation 1.5's K-16 Trajectories

    ERIC Educational Resources Information Center

    Garnett, Bruce

    2012-01-01

    Little empirical research has ever systematically documented the academic trajectories of Generation 1.5 in Canadian schools. Indeed, this label has not even been used to define the population of interest in the studies reviewed here. Nonetheless, some earlier work, along with more current studies made possible by recent availability of data, has…

  2. Super Seniors: The Educational Trajectories and Experiences of Graduate(d) Student Athletes in Division I Football

    ERIC Educational Resources Information Center

    Haslerig, Siduri

    2013-01-01

    Using narrative data collected through semi-structured phone interviews with eleven "graduate(d) student athletes," this dissertation examines participants' academic trajectories and experiences. Theories regarding role-conflict, attribution, college choice and career maturity undergird analysis. Findings are divided into four chapters:…

  3. Debt trajectories and mental health.

    PubMed

    Hojman, Daniel A; Miranda, Álvaro; Ruiz-Tagle, Jaime

    2016-10-01

    In the last few decades, there was a marked increase in consumer debt in the United States, Latin America and other emerging countries, spurring a debate about the real costs and benefits of household credit. Using a unique longitudinal dataset with detailed health and balance sheet information from a large sample of 10,900 Chilean households we study the relationship between debt trajectories in a three-year time window and mental health. We find that depressive symptoms are higher for those who have been persistently over-indebted, followed by those who transit from moderate to high debt levels. We also find that those who transition from over-indebtedness to moderate debt levels have no additional depressive symptoms compared to those with trajectories of moderate debt throughout (never over-indebted). This suggests that the debt-related contribution to depressive symptoms vanishes as debt levels fall. The association between debt and depressive symptoms seems to be driven by non-mortgage debt -primarily consumer credit- or late mortgage payments; secured debt (secured by collateral) per se is not associated with depressive symptoms. Policy interventions to reduce the negative association of over-indebtedness on mental health are discussed.

  4. TOPTRAC: Topical Trajectory Pattern Mining

    PubMed Central

    Kim, Younghoon; Han, Jiawei; Yuan, Cangzhou

    2015-01-01

    With the increasing use of GPS-enabled mobile phones, geo-tagging, which refers to adding GPS information to media such as micro-blogging messages or photos, has seen a surge in popularity recently. This enables us to not only browse information based on locations, but also discover patterns in the location-based behaviors of users. Many techniques have been developed to find the patterns of people's movements using GPS data, but latent topics in text messages posted with local contexts have not been utilized effectively. In this paper, we present a latent topic-based clustering algorithm to discover patterns in the trajectories of geo-tagged text messages. We propose a novel probabilistic model to capture the semantic regions where people post messages with a coherent topic as well as the patterns of movement between the semantic regions. Based on the model, we develop an efficient inference algorithm to calculate model parameters. By exploiting the estimated model, we next devise a clustering algorithm to find the significant movement patterns that appear frequently in data. Our experiments on real-life data sets show that the proposed algorithm finds diverse and interesting trajectory patterns and identifies the semantic regions in a finer granularity than the traditional geographical clustering methods. PMID:26709365

  5. Discrimination and identification of periodic motion trajectories.

    PubMed

    Or, Charles C-F; Thabet, Michel; Wilkinson, Frances; Wilson, Hugh R

    2011-07-12

    Humans are extremely sensitive to radial deformations of static circular contours (F. Wilkinson, H. R. Wilson, & C. Habak, 1998). Here, we investigate detection and identification of periodic motion trajectories defined by these radial frequency (RF) patterns over a range of radial frequencies of 2-5 cycles. We showed that the average detection thresholds for RF trajectories range from 1 to 4 min of arc and performance improves as a power-law function of radial frequency. RF trajectories are also detected for a range of speeds. We also showed that spatiotemporal global processing is involved in trajectory detection, as improvement in detection performance with increasing radial deformation displayed cannot be accounted for by local probability summation. Finally, identification of RF trajectories is possible over this RF range. Overall thresholds are about 6 times higher than previously reported for static stimuli. These novel stimuli should be a useful tool to investigate motion trajectory learning and discrimination in humans and other primates.

  6. Computer optimization of a linac injector trajectory

    SciTech Connect

    Sawyer, C.; Detch, J.L. Jr.

    1984-01-01

    One can determine a computer prediction of the beam radius as a function of axial distance for a linac beam by providing a set of inputs to the computer code, ZFIELD. The trajectory may be improved by varying the magnet current values in the code, but repeated trails may still not attain the best trajectory. Starting with a set of points containing the desired trajectory, one may work the problem backwards and obtain the necessary magnet currents required by the trajectory. In the examples given, a portion of the trajectory is chosen to be parabolic. The trajectory information is used with a differential equation involving beam radius and its derivatives to yield the magnetic field as a function of axial position. Matrix methods are used to obtain the magnet currents from the magnetic field. 4 references, 6 figures.

  7. Stochastic and fractal analysis of fracture trajectories

    NASA Technical Reports Server (NTRS)

    Bessendorf, Michael H.

    1987-01-01

    Analyses of fracture trajectories are used to investigate structures that fall between 'micro' and 'macro' scales. It was shown that fracture trajectories belong to the class of nonstationary processes. It was also found that correlation distance, which may be related to a characteristic size of a fracture process, increases with crack length. An assemblage of crack trajectory processes may be considered as a diffusive process. Chudnovsky (1981-1985) introduced a 'crack diffusion coefficient' d which reflects the ability of the material to deviate the crack trajectory from the most energetically efficient path and thus links the material toughness to its structure. For the set of fracture trajectories in AISI 304 steel, d was found to be equal to 1.04 microns. The fractal dimension D for the same set of trajectories was found to be 1.133.

  8. Strategies for developing biostatistics resources in an academic health center.

    PubMed

    Welty, Leah J; Carter, Rickey E; Finkelstein, Dianne M; Harrell, Frank E; Lindsell, Christopher J; Macaluso, Maurizio; Mazumdar, Madhu; Nietert, Paul J; Oster, Robert A; Pollock, Brad H; Roberson, Paula K; Ware, James H

    2013-04-01

    Biostatistics--the application of statistics to understanding health and biology-provides powerful tools for developing research questions, designing studies, refining measurements, analyzing data, and interpreting findings. Biostatistics plays an important role in health-related research, yet biostatistics resources are often fragmented, ad hoc, or oversubscribed within academic health centers (AHCs). Given the increasing complexity and quantity of health-related data, the emphasis on accelerating clinical and translational science, and the importance of conducting reproducible research, the need for the thoughtful development of biostatistics resources within AHCs is growing.In this article, the authors identify strategies for developing biostatistics resources in three areas: (1) recruiting and retaining biostatisticians, (2) efficiently using biostatistics resources, and (3) improving biostatistical contributions to science. AHCs should consider these three domains in building strong biostatistics resources, which they can leverage to support a broad spectrum of research. For each of the three domains, the authors describe the advantages and disadvantages of AHCs creating centralized biostatistics units rather than dispersing such resources across clinical departments or other research units. They also address the challenges that biostatisticians face in contributing to research without sacrificing their individual professional growth or the trajectory of their research teams. The authors ultimately recommend that AHCs create centralized biostatistics units because this approach offers distinct advantages both to investigators who collaborate with biostatisticians as well as to the biostatisticians themselves, and it is better suited to accomplish the research and education missions of AHCs.

  9. Academic Probation Intervention through Academic Assistance Advising

    ERIC Educational Resources Information Center

    Preuss, Michael; Switalski, Rachael

    2008-01-01

    Retaining and aiding students on academic probation is a concern for all institutions of higher education. Students placed on academic probation by Rockingham Community College (RCC) have been encouraged to participate in an intervention program since the summer of 2006. When treated as an aggregate, the data regarding the program indicates that…

  10. Random Trajectory Modeling of Limited-Volume Percolation in a Microporous Structure.

    PubMed

    Romm, Freddy

    2001-08-01

    The limited-volume analytical method for the evaluation of the probability of percolation (random trajectory approach) is developed. The model uses probabilistic analysis of possible percolation ways. The main equation for the probability of percolation contains parameters related to the conditions of formation of the microporous medium. Results of some computer estimations of the influence of various formation-related parameters (porosity, surface tension, coordination number, etc.) are presented. Copyright 2001 Academic Press.

  11. Numerical Study of Orbital Trajectories about Phobos

    DTIC Science & Technology

    1988-12-01

    COF NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain, USAF AFIT/GS0/AA/8 8D- 16 ..................D TIC SELECTEh...ful em t%... . 𔄂 9 ... 3 ...29 ...058_... AFIT/GSO/AA/88D-16 0 NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain...ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Presented to the Faculty of the School of Engineering of the Air Force Institute of Technology Air University In

  12. Anomaly Detection and Modeling of Trajectories

    DTIC Science & Technology

    2012-08-01

    unsupervised fashion using support vector machines (SVMs) and various spatial representations of trajectories. This thesis will also focus on...empirically to provide a rich analysis of trajectory datasets. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as...based on the rest of the dataset. This thesis develops a technique for detecting anoma- lous trajectories in a dataset in an unsupervised fashion using

  13. The Jupiter Icy Moons Orbiter reference trajectory

    NASA Technical Reports Server (NTRS)

    Whiffen, Gregory J.; Lam, Try

    2006-01-01

    The proposed NASA Jupiter Icy Moons Orbiter (JIMO) mission would have used a single spacecraft to orbit Callisto, Ganymede, and Europa in succession. The enormous Delta-Velocity required for this mission (nearly [25 km/s]) would necessitate the use of very high efficiency electric propulsion. The trajectory created for the proposed baseline JIMO mission may be the most complex trajectory ever designed. This paper describes the current reference trajectory in detail and describes the processes that were used to construct it.

  14. Association of Academic Physiatrists

    MedlinePlus

    Donate Member Portal Search Search » Donate | Member Portal | Sign In | Join Membership Join the AAP Coming Home Member Benefits Top 5 Reasons to Join Categories & Dues Academic Partnership Program Current Academic ...

  15. Trajectories of youthful antisocial behavior: categories or continua?

    PubMed

    Walters, Glenn D; Ruscio, John

    2013-05-01

    The purpose of this study was to determine whether qualitatively distinct trajectories of antisocial behavior could be identified in 1,708 children (843 boys, 865 girls) from the 1979 National Longitudinal Survey of Youth-Child Data (NLSY-C). Repeated ratings were made on the Behavior Problems Index (BPI: Peterson and Zill Journal of Marriage and the Family, 48, 295-307, 1986) antisocial scale by the mothers of these children when the children were 6, 8, 10, 12, and 14 years of age. Scores on three indicators constructed from the six BPI Antisocial items (callousness, aggression, noncompliance) were then analyzed longitudinally (by summing across the rating periods) and cross-sectionally (by testing each individual rating period) in the full sample as well as in subsamples of boys and girls. Results obtained with the mean above minus below a cut (MAMBAC), maximum covariance (MAXCOV), and latent mode factor analysis (L-Mode) taxometric procedures revealed consistent evidence of continuous latent structure despite the fact Growth Mixture Modeling (GMM) and Latent Class Growth Analysis (LCGA) identified between two and eight trajectories, depending on the stopping rule, in the three antisocial indicators. From these results, it is concluded that the structural model underlying these data is better represented as continuous rather than as categorical. The implications of these results for future research on developmental trajectories of antisocial behavior are discussed.

  16. Trajectory analysis of a soccer ball

    NASA Astrophysics Data System (ADS)

    Goff, John Eric; Carré, Matt J.

    2009-11-01

    We performed experiments in which a soccer ball was launched from a machine while two cameras recorded portions of its trajectory. Drag coefficients were obtained from range measurements for no-spin trajectories, for which the drag coefficient does not vary appreciably during the ball's flight. Lift coefficients were obtained from the trajectories immediately following the ball's launch, in which Reynolds number and spin parameter do not vary much. We obtain two values of the lift coefficient for spin parameters that had not been obtained previously. Our codes for analyzing the trajectories are freely available to educators and students.

  17. NBODY - a multipurpose trajectory optimization computer program

    NASA Technical Reports Server (NTRS)

    Strack, W. C.

    1974-01-01

    Documentation of the NBODY trajectory optimization program is presented in the form of a mathematical development plus a user's manual. Optimal multistage-launch ascent trajectories may be determined by variational thrust steering during the upper phase. Optimal low-thrust interplanetary spacecraft trajectories may also be calculated with solar power or constant power, all-propulsion or embedded coast arcs, fixed or optimal thrust angles, and a variety of terminal end conditions. A hybrid iteration scheme solves the boundary-value problem, while either transversality conditions or a univariate search scheme optimize vehicle or trajectory parameters.

  18. Global trajectory targeting via computer graphics

    NASA Technical Reports Server (NTRS)

    Mann, F. I.

    1971-01-01

    A technique is described in which the two-point boundary value problem (TPBVP) may be solved with the aid of interactive computer graphics. The particular TPBVP considered is the optimal electric propulsion space trajectory problem. An appropriate two-dimensional projection of the TPBVP mapping, or trajectory, is displayed on the computer's television screen, and a man-in-the-loop varies selected trajectory starting conditions in the fashion of a nonlinear walk until the viewed trajectory endpoint lies near a displayed target. Once global targeting is accomplished in this manner, program internal logic can easily handle local targeting to strongly solve the TPBVP.

  19. Growth curve analyses of the relationship between early maternal age and children's mathematics and reading performance.

    PubMed

    Torres, D Diego

    2015-03-01

    Regarding the methods used to examine the early maternal age-child academic outcomes relationship, the extant literature has tended to examine change using statistical analyses that fail to appreciate that individuals vary in their rates of growth. Of the one study I have been able to find that employs a true growth model to estimate this relationship, the authors only controlled for characteristics of the maternal household after family formation; confounding background factors of mothers that might select them into early childbearing, a possible source of bias, were ignored. The authors' findings nonetheless suggested an inverse relationship between early maternal age, i.e., a first birth between the ages of 13 and 17, and Canadian adolescents' mean math performance at age 10. Early maternal age was not related to the linear slope of age. To elucidate whether the early maternal age-child academic outcomes association, treated in a growth context, is consistent with this finding, the present study built on it using US data and explored children's mathematics and reading trajectories from age 5 on. Its unique contribution is that it further explicitly controlled for maternal background factors and employed a three-level growth model with repeated measures of children nested within their mothers. Though the strength of the relationship varied between mean initial academic performance and mean academic growth, results confirmed that early maternal age was negatively related to children's mathematics and reading achievement, net of post-teen first birth child-specific and maternal household factors. Once maternal background factors were included, there was no statistically significant relationship between early maternal age and either children's mean initial mathematics and reading scores or their mean mathematics and reading growth.

  20. Two-year trajectory of fall risk in people with Parkinson’s disease: a latent class analysis

    PubMed Central

    Paul, Serene S; Thackeray, Anne; Duncan, Ryan P; Cavanaugh, James T; Ellis, Theresa D; Earhart, Gammon M; Ford, Matthew P; Foreman, K Bo; Dibble, Leland E

    2015-01-01

    Objective To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson’s disease (PD). Design Latent class analysis, specifically growth mixture modeling (GMM) of longitudinal fall risk trajectories. Setting Not applicable. Participants 230 community-dwelling PD participants of a longitudinal cohort study who attended at least two of five assessments over a two year period. Interventions Not applicable. Main Outcome Measures Fall risk trajectory (low, medium or high risk) and stability of fall risk trajectory (stable or fluctuating). Fall risk was determined at 6-monthly intervals using a simple clinical tool based on fall history, freezing of gait, and gait speed. Results The GMM optimally grouped participants into three fall risk trajectories that closely mirrored baseline fall risk status (p=.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium risk trajectories (p<.001). Fluctuating fall risk (posterior probability <0.8 of belonging to any trajectory) was found in only 22.6% of the sample, most commonly among individuals who were transitioning to PIGD predominance. Conclusions Regardless of their baseline characteristics, most participants had clear and stable fall risk trajectories over two years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD. PMID:26606871

  1. Longitudinal Trajectories of Marijuana Use from Adolescence to Young Adulthood

    PubMed Central

    Passarotti, A.M.; Crane, Natania A.; Hedeker, Donald; Mermelstein, Robin J.

    2015-01-01

    Background Marijuana use is increasingly widespread among adolescents and young adults; however, few studies have examined longitudinal trajectories of marijuana use during this important developmental period. As such, we examined adolescent trajectories of marijuana use and the psychosocial factors that may differentiate individuals who escalate their marijuana use over adolescence and young adulthood from those who do not. Methods Participants were 1,204 9th and 10th graders at baseline who were over-sampled for cigarette use and were followed over 6-years, as part of an extensive longitudinal study, the Social and Emotional Contexts of Adolescent Smoking Patterns (SECASP) study. Growth Mixture Modeling (GMM) was used to model trajectories of marijuana use and Mixed Effects Regression analyses were used to examine psychosocial correlates of marijuana use escalation over time. Results Our results revealed three trajectories of non-escalating users (low users, medium users, and high users) and one escalating user trajectory. We found that relative to Non-escalators the Escalators had higher cigarette smoking (p<.0001), novelty-seeking (p=.02), aggressive and anti-social behavior (p<.007), and problem behavior related to peer context (p=.04). Moreover, there were important time and group by time interactions in some of these relationships. On the other hand, parental control and depression did not differ between escalators and low and medium non-escalating users. Conclusions Cigarette smoking, novelty-seeking, aggressive and anti-social behavior, and peer influence are related to ‘escalating’ marijuana use throughout adolescence and young adulthood. PMID:25792233

  2. Retired Status and Older Adults’ 10-Year Drinking Trajectories*

    PubMed Central

    Brennan, Penny L.; Schutte, Kathleen K.; Moos, Rudolf H.

    2010-01-01

    Objective: Little research has examined the role of retirement in shaping late-life drinking careers, and it has generally been limited to cross-sectional designs or short-term follow-ups that emphasize group-level comparisons of retirees and nonretirees. The purpose of this study was to determine the following: (a) the effect of retired status on older adults’ 10-year within-person drinking trajectories and (b) whether age, gender, income, health, and problem-drinker status account for or moderate this effect. Method: We first estimated older adults’ (baseline M= 62 years; n = 595) 10-year within-person drinking trajectories using three successively predictive multilevel regression models: unconditional growth, retired status alone, and retired status controlling for covariates. Next, we determined whether inclusion of Retired Status × Covariate interactions would improve prediction of the trajectories. Results: Participants’ drinking frequency declined moderately over the 10-year interval, and retired status hastened the decline. However, this effect disappeared once covariates were added to the model: Baseline poorer health, lower income, and current problem-drinker status predicted steeper decline in drinking frequency, whereas former problem-drinker status predicted slower decline. Lower income and current drinking problems also predicted steeper declines in amount of alcohol consumed. There were no statistically significant or uniquely contributive interactions between retired status and age, gender, health, income, or drinking problems for predicting late-life drinking trajectories. Conclusions: Baseline health, income, and problem-drinking history are more important than retired status for predicting older adults’ long-term within-person drinking trajectories. These factors—and recency of drinking problems—should be considered in future studies of retirement and late-life drinking patterns. PMID:20230712

  3. Nonadiabatic Molecular Dynamics with Trajectories

    NASA Astrophysics Data System (ADS)

    Tavernelli, Ivano

    2012-02-01

    In the mixed quantum-classical description of molecular systems, only the quantum character of the electronic degrees of freedom is considered while the nuclear motion is treated at a classical level. In the adiabatic case, this picture corresponds to the Born-Oppenheimer limit where the nuclei move as point charges on the potential energy surface (PES) associated with a given electronic state. Despite the success of this approximation, many physical and chemical processes do not fall in the regime where nuclei and electrons can be considered decoupled. In particular, most photoreactions pass through regions of the PES in which electron-nuclear quantum interference effects are sizeable and often crucial for a correct description of the phenomena. Recently, we have developed a trajectory-based nonadiabatic molecular dynamics scheme that describes the nuclear wavepacket as an ensemble of particles following classical trajectories on PESs derived from time-dependent density functional theory (TDDFT) [1]. The method is based on Tully's fewest switches trajectories surface hopping (TSH) where the nonadiabatic coupling elements between the different potential energy surfaces are computed on-the-fly as functionals of the ground state electron density or, equivalently, of the corresponding Kohn-Sham orbitals [2]. Here, we present the theoretical fundamentals of our approach together with an extension that allows for the direct coupling of the dynamics to an external electromagnetic field [3] as well as to the external potential generated by the environment (solvent effects) [4]. The method is applied to the study of the photodissociation dynamics of simple molecules in gas phase and to the description of the fast excited state dynamics of molecules in solution (in particular Ruthenium (II) tris(bipyridine) in water). [4pt] [1] E. Tapavicza, I. Tavernelli, U. Rothlisberger, Phys. Rev. Lett., 98, (2007) 023001. [0pt] [2] Tavernelli I.; Tapavicza E.; Rothlisberger U., J. Chem

  4. Academic Inbreeding in Nursing

    ERIC Educational Resources Information Center

    Miller, Michael H.

    1977-01-01

    Academic inbreeding, the employment for faculty positions of persons who receive their graduate training at the same academic institution, is considered detrimental to an institution's academic environment. Results of a study conducted at 54 universities revealed that almost half the faculty (48 percent) in collegiate nursing programs are drawn…

  5. The Academic Adviser

    ERIC Educational Resources Information Center

    Darling, Ruth

    2015-01-01

    In this essay, I explore the idea that "academic" advisers are "academics" who play a major role in connecting the general education curriculum to the students' experience as well as connecting the faculty to the students' holistic experience of the curriculum. The National Academic Advising Association Concept of Academic…

  6. What Is Academic Vocabulary?

    ERIC Educational Resources Information Center

    Baumann, James F.; Graves, Michael F.

    2010-01-01

    In this article, the authors address the construct of "academic vocabulary." First, they attempt to bring some clarity to a constellation of terms surrounding academic vocabulary. Second, they compare and contrast definitions of academic vocabulary. Third, they review typologies that researchers and writers have proposed to organize academic…

  7. Longitudinal Trajectories of Food Insecurity Among Children of Immigrants.

    PubMed

    Miller, Daniel P; Chang, Jina; Ha, Yoonsook; Sprague Martinez, Linda

    2016-11-09

    Although research consistently points to higher rates of food insecurity (FI) among children of immigrants (COI), this is the first study to examine longitudinal trajectories of FI for this group. We used growth curve modeling and data from the 1998 Early Childhood Longitudinal Study-Kindergarten Cohort to compare trajectories of FI for COI and children of U.S.-born parents. After controlling for socioeconomic status and participation in nutrition programs, first- and second-generation COI had significantly higher initial and ongoing rates of FI compared to children of U.S.-born parents. Additional analyses found that all differences between COI and children of U.S.-born parents occurred for families in poverty. We find that COI from poor families have higher rates of FI, with some differences among COI by immigrant generation. Policymakers may need to focus on avenues other than public assistance to reduce FI among COI living in poverty.

  8. Trajectories of Conflict over Raising Adolescent Children and Marital Satisfaction

    PubMed Central

    Cui, Ming; Donnellan, M. Brent

    2009-01-01

    The present study examined trajectories of marital satisfaction among couples with adolescent children and evaluated how changes in parents’ conflict over raising adolescent children were associated with changes in marital satisfaction over four years. Using a prospective, longitudinal research design and controlling for family socioeconomic status, dyadic growth curve analysis from a sample of 431 couples with adolescent children indicated that marital satisfaction decreased over time for parents with adolescent children, and that the trajectories for mothers and fathers were substantially linked. More importantly, the study demonstrated that increases or decreases in parents’ marital conflict over raising adolescent children were associated with corresponding decreases or increases in marital satisfaction for both mothers and fathers. PMID:20161030

  9. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1986-01-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

  10. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1987-03-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

  11. Curved dyke trajectories beneath a mature volcanic edifice

    NASA Astrophysics Data System (ADS)

    Roman, A. M.; Jaupart, C. P.

    2013-12-01

    Curved dyke trajectories, prominently displayed at Spanish Peaks, Colorado, and observed in many different volcanic areas on Earth as well as on Venus, have been attributed to horizontal dyke propagation in a stress field that involves two different components: one due to magmatic overpressure in an central reservoir and another due to the regional tectonics. This model is not consistent with petrological and chronological constraints at Spanish Peaks: the dykes are filled with more evolved magmas than those of the central stock and are unambiguously younger than the stock (by about 1 My). These dykes are nowhere in contact with the stock and only appear at significant distances from it. For consistency with the observed trajectories, quantitative models of dyke propagation lead to very small values of the far-field tectonic stress that indicate very shallow levels of emplacement (≈1-2 km at most). At such small depths, the mechanics of deformation do not allow the growth of sizeable magmatic reservoirs. We propose instead that curved dyke trajectories are due to the combined effects of loading by a volcanic edifice in the axial zone and tectonic stresses in the far-field. We calculate principal stress trajectories and show that they exhibit the desired features. These trajectories are radially oriented beneath the edifice and bend away with increasing distance to align themselves with the tectonic stress. This model requires edifices with radii in the 5-15 km range and heights in the 1-3 km range, which are typical of mature stratovolcanoes worldwide. At Spanish Peaks, this model implies that the magmatic plumbing system that fed volcanic and intrusive activity developed in a manner consistent with the mechanics of dyke propagation beneath an edifice. Loading by a mature edifice generated a compressive stress field that prevented eruption in the central area. Dyke growth in the vertical direction was hampered beneath the highest part of the edifice and could

  12. Academic adjustment across middle school: the role of public regard and parenting.

    PubMed

    McGill, Rebecca Kang; Hughes, Diane; Alicea, Stacey; Way, Niobe

    2012-07-01

    In the current longitudinal study, we examined associations between Black and Latino youths' perceptions of the public's opinion of their racial/ethnic group (i.e., public regard) and changes in academic adjustment outcomes across middle school. We also tested combinations of racial/ethnic socialization and parent involvement in academic activities as moderators of this association. We used a 2nd-order latent trajectory model to test changes in academic adjustment outcomes in a sample of 345 Black and Latino urban youth across 6th, 7th, and 8th grades (51% female). Results revealed a significant average linear decline in academic adjustment from 6th to 8th grade, as well as significant variation around this decline. We found that parenting moderated the association between public regard and the latent trajectory of academic adjustment. Specifically, for youth who reported high racial/ethnic socialization and low parent academic involvement, lower public regard predicted lower academic adjustment in 6th grade. For youth who reported both low racial/ethnic socialization and low parent academic involvement, lower public regard predicted a steeper decline in academic adjustment over time. Finally, among youth who reported high racial/ethnic socialization and high parent academic involvement, public regard was not associated with either the intercept or the slope of academic adjustment. Thus, the combination of high racial/ethnic socialization and parent academic involvement may protect youths' academic motivation and performance from the negative effects of believing the public has low opinions of one's racial/ethnic group. Implications for protecting Black and Latino youths' academic outcomes from decline during middle school are discussed.

  13. Automating Initial Guess Generation for High Fidelity Trajectory Optimization Tools

    NASA Technical Reports Server (NTRS)

    Villa, Benjamin; Lantoine, Gregory; Sims, Jon; Whiffen, Gregory

    2013-01-01

    Many academic studies in spaceflight dynamics rely on simplified dynamical models, such as restricted three-body models or averaged forms of the equations of motion of an orbiter. In practice, the end result of these preliminary orbit studies needs to be transformed into more realistic models, in particular to generate good initial guesses for high-fidelity trajectory optimization tools like Mystic. This paper reviews and extends some of the approaches used in the literature to perform such a task, and explores the inherent trade-offs of such a transformation with a view toward automating it for the case of ballistic arcs. Sample test cases in the libration point regimes and small body orbiter transfers are presented.

  14. Trajectories of parenting behavior and maternal depression.

    PubMed

    Azak, Schale; Raeder, Sabine

    2013-06-01

    This study investigated trajectories of maternal parenting behavior across the infants' first 18 months of life in relation to maternal depression. Furthermore, predictors of the quality of the mother-infant relationship at 18 months were examined. Participants consisted of three types of mother-infant dyads: mothers with comorbid depression and anxiety (n=19), mothers with depression (n=7) and nondepressed mothers (n=24). Maternal behaviors and the quality of relationship were rated on a global scale (NICHD) from video-taped mother-infant interactions. Maternal behaviors rated at six, 12 and 18 months were collapsed into a composite variable maternal style. The quality of the relationship captured as dyadic mutuality was rated at 18 months. Comorbid and depressed mothers showed lower quality in maternal style compared with the nondepressed mothers at six months. Over the follow-up the comorbid mothers were lower in maternal style compared to the nondepressed mothers, but the comorbid mothers increased significantly in maternal style despite elevated depression symptoms. Mean maternal style and infant cognitive skills predicted the quality in relationship at 18 months suggesting that the mother-toddler relationship depends on contributions from the mother and the child. Higher growth in maternal style despite of depression symptoms among comorbid mothers was interpreted against the background that the majority of the comorbid mother-infant dyads received several treatments.

  15. Explaining Asian Americans' academic advantage over whites.

    PubMed

    Hsin, Amy; Xie, Yu

    2014-06-10

    The superior academic achievement of Asian Americans is a well-documented phenomenon that lacks a widely accepted explanation. Asian Americans' advantage in this respect has been attributed to three groups of factors: (i) socio-demographic characteristics, (ii) cognitive ability, and (iii) academic effort as measured by characteristics such as attentiveness and work ethic. We combine data from two nationally representative cohort longitudinal surveys to compare Asian-American and white students in their educational trajectories from kindergarten through high school. We find that the Asian-American educational advantage is attributable mainly to Asian students exerting greater academic effort and not to advantages in tested cognitive abilities or socio-demographics. We test explanations for the Asian-white gap in academic effort and find that the gap can be further attributed to (i) cultural differences in beliefs regarding the connection between effort and achievement and (ii) immigration status. Finally, we highlight the potential psychological and social costs associated with Asian-American achievement success.

  16. Challenges in Modeling and Measuring Learning Trajectories

    ERIC Educational Resources Information Center

    Confrey, Jere; Jones, R. Seth; Gianopulos, Garron

    2015-01-01

    Briggs and Peck make a compelling case for creating new, more intuitive measures of learning, based on creating vertical scales using learning trajectories (LT) in place of "domain sampling." We believe that the importance of creating measurement scales that coordinate recognizable landmarks in learning trajectories with interval scales…

  17. Guidance trajectories for aeroassisted orbital transfer

    NASA Technical Reports Server (NTRS)

    Miele, A.

    1990-01-01

    Research on aerobraking guidance schemes is presented. The intent is to produce aerobraking guidance trajectories exhibiting many of the desirable characteristics of optimal aerobraking trajectories. Both one-control schemes and two-control schemes are studied. The research is in the interest of aeroassisted flight experiment vehicles (AFE) and aeroassisted orbital transfer (AOT) vehicles.

  18. Projecting uncertainty onto marine megafauna trajectories

    NASA Astrophysics Data System (ADS)

    Robel, Alexander A.; Susan Lozier, M.; Gary, Stefan F.; Shillinger, George L.; Bailey, Helen; Bograd, Steven J.

    2011-09-01

    In this study, a method is proposed for estimating the uncertainty of a Lagrangian pathway calculated from an undersampled ocean surface velocity field. The primary motivation and application for this method is the differentiation between active and passive movements for sea turtles whose trajectories are observed with satellite telemetry. Synthetic trajectories are launched within a reconstructed surface velocity field and integrated forward in time to produce likely trajectories of an actual turtle or drifter. Uncertainties in both the initial conditions at launch and the velocity field along the trajectory are used to yield an envelope of possible synthetic trajectories for each actual trajectory. The juxtaposition of the actual trajectory with the resulting cloud of synthetic trajectories provides a means to distinguish between active and passive movements of the turtle. The uncertainty estimates provided by this model may lead to improvements in our understanding of where and when turtles are engaged in specific behaviors (i.e. migration vs. foraging)—for which potential management efforts may vary accordingly.

  19. Soccer Ball Lift Coefficients via Trajectory Analysis

    ERIC Educational Resources Information Center

    Goff, John Eric; Carre, Matt J.

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

  20. Minimum jerk trajectory planning for robotic manipulators

    NASA Technical Reports Server (NTRS)

    Kyriakopoulos, K. J.; Saridis, G. N.

    1991-01-01

    It has been experimentally verified that the jerk of the desired trajectory adversely affects the performance of the tracking control algorithms for robotic manipulators. In this paper, the reasons behind this effect are investigated, and an optimization problem that minimizes joint jerk over a prespecified Cartesian space trajectory is stated. The necessary conditions are derived, and a numerical algorithm is presented.

  1. Simulation of Airplane and Rocket Trajectories

    NASA Technical Reports Server (NTRS)

    Wahbah, Magdy M.; Berning, Michael J.; Choy, Tony S.

    1987-01-01

    Simulation and Optimization of Rocket Trajectories program (SORT) contains comprehensive mathematical models for simulating aircraft dynamics, freely falling objects, and many types of ballistic trajectories. Provides high-fidelity, three-degrees-of-freedom simulation for atmospheric and exoatmospheric flight. It numerically models vehicle subsystems and vehicle environment. Used for wide range of simulations. Written in machine-independent FORTRAN 77.

  2. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... a programmed thrust termination. (3) For launch vehicles flown with a flight safety system, a... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.207 Trajectory analysis. (a) General. A flight safety analysis must include a trajectory analysis that establishes: (1) For any...

  3. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... a programmed thrust termination. (3) For launch vehicles flown with a flight safety system, a... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.207 Trajectory analysis. (a) General. A flight safety analysis must include a trajectory analysis that establishes: (1) For any...

  4. Trajectories of Delinquency and Parenting Styles

    ERIC Educational Resources Information Center

    Hoeve, Machteld; Blokland, Arjan; Dubas, Judith Semon; Loeber, Rolf; Gerris, Jan R. M.; van der Laan, Peter H.

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering ages 10-19, we identified five distinct…

  5. Application of Taylor's series to trajectory propagation

    NASA Technical Reports Server (NTRS)

    Stanford, R. H.; Berryman, K. W.; Breckheimer, P. J.

    1986-01-01

    This paper describes the propagation of trajectories by the application of the preprocessor ATOMCC which uses Taylor's series to solve initial value problems in ordinary differential equations. Comparison of the results obtained with those from other methods are presented. The current studies indicate that the ATOMCC preprocessor is an easy, yet fast and accurate method for generating trajectories.

  6. Positive Illusions in the Academic Context: A Longitudinal Study of Academic Self-Enhancement in College.

    PubMed

    Chung, Joanne; Schriber, Roberta A; Robins, Richard W

    2016-10-01

    In the present research, we examined academic self-enhancement in students (N = 264) followed longitudinally through 4 years of college. We used social comparison (i.e., better-than-average ratings) and self-insight (i.e., criterion-based) approaches to assess the degree to which students self-enhanced in their self-perceptions of academic ability, with SAT scores, high school grade point average (GPA), and college GPA used as criterion measures. We also examined ethnic variability in academic self-enhancement. We found that academic self-enhancement (a) increased or decreased over the 4 years of college, depending on its operationalization, (b) tended to be adaptive according to social comparison indices, and (c) demonstrated a trajectory that differed by ethnicity, but ethnicity did not moderate the effect of academic self-enhancement on outcomes. We discuss the implications of the findings for debates about the adaptive value of self-enhancement, the magnitude of cultural differences, and how best to conceptualize and operationalize the construct.

  7. Physical exercise alleviates ADHD symptoms: regional deficits and development trajectory.

    PubMed

    Archer, Trevor; Kostrzewa, Richard M

    2012-02-01

    The heterogeneous, chronic, and proliferating aspect of attention deficit hyperactivity disorder (ADHD) and comorbidities covers heritability, cognitive, emotional, motor, and everyday behavioral domains that place individuals presenting the condition at some considerable disadvantage. Disruption of "typical developmental trajectories" in the manifestation of gene-environment interactive predispositions implies that ADHD children and adolescents may continue to perform at defective levels as adults with regard to academic achievement, occupational enterprises, and interpersonal relationships, despite the promise of pharmacotherapeutic treatments. Physical exercise provides a plethora of beneficial effects against stress, anxiety, depression, negative affect and behavior, poor impulse control, and compulsive behavior concomitant with improved executive functioning, working memory and positive affect, as well as improved conditions for relatives and care-givers. Brain-derived neurotrophic factor, an essential element in normal brain development that promotes health-associated behaviors and quality-of-life, though reduced in ADHD, is increased markedly by the intervention of regular physical exercise. Functional, regional, and biomarker deficits, as well as hypothalamic-pituitary-adrenal disruptions, have been improved through regular and carefully applied exercise programs. In view of the complications involving ADHD with co-morbidities, such as obesity, the influence of regular physical exercise has not been found negligible. Physical exercise bestows a propensity for eventual manifestation of "redifferentiated" developmental trajectories that may equip ADHD adults with a prognosis that is more adaptive functionally, independent of the applications of other therapeutic agents and treatments.

  8. Unique Associations between Childhood Temperament Characteristics and Subsequent Psychopathology Symptom Trajectories from Childhood to Early Adolescence.

    PubMed

    Forbes, Miriam K; Rapee, Ronald M; Camberis, Anna-Lisa; McMahon, Catherine A

    2016-12-09

    Existing research suggests that temperamental traits that emerge early in childhood may have utility for early detection and intervention for common mental disorders. The present study examined the unique relationships between the temperament characteristics of reactivity, approach-sociability, and persistence in early childhood and subsequent symptom trajectories of psychopathology (depression, anxiety, conduct disorder, and attention-deficit hyperactivity disorder; ADHD) from childhood to early adolescence. Data were from the first five waves of the older cohort from the Longitudinal Study of Australian Children (n = 4983; 51.2% male), which spanned ages 4-5 to 12-13. Multivariate ordinal and logistic regressions examined whether parent-reported child temperament characteristics at age 4-5 predicted the study child's subsequent symptom trajectories for each domain of psychopathology (derived using latent class growth analyses), after controlling for other presenting symptoms. Temperament characteristics differentially predicted the symptom trajectories for depression, anxiety, conduct disorder, and ADHD: Higher levels of reactivity uniquely predicted higher symptom trajectories for all 4 domains; higher levels of approach-sociability predicted higher trajectories of conduct disorder and ADHD, but lower trajectories of anxiety; and higher levels of persistence were related to lower trajectories of conduct disorder and ADHD. These findings suggest that temperament is an early identifiable risk factor for the development of psychopathology, and that identification and timely interventions for children with highly reactive temperaments in particular could prevent later mental health problems.

  9. Developmental trajectories of marital happiness in continuously married individuals: a group-based modeling approach.

    PubMed

    Anderson, Jared R; Van Ryzin, Mark J; Doherty, William J

    2010-10-01

    Most contemporary studies of change in marital quality over time have used growth curve modeling to describe continuously declining mean curves. However, there is some evidence that different trajectories of marital quality exist for different subpopulations. Group-based trajectory modeling provides the opportunity to conduct an empirical investigation of the variance in marital quality trajectories. We applied this method to analyze data from continuously married individuals from the Marital Instability over the Life Course Study (N = 706). Instead of a single continuously declining trajectory of marital happiness, we found 5 distinct trajectories. Nearly two thirds of participants reported high and stable levels of happiness over time, and the other one third showed either a pattern of continuous low happiness, low happiness that subsequently declined, or a curvilinear pattern of high happiness, decline, and recovery. Marital problems, time spent in shared activities, and (to a lesser degree) economic hardship were able to distinguish trajectory group membership. Our results suggest that marital happiness may have multiple distinct trajectories across reasonably diverse populations. Implications for theory, research, and practice are discussed.

  10. Housing Trajectories of Forensic Psychiatric Patients.

    PubMed

    Salem, Leila; Crocker, Anne G; Charette, Yanick; Earls, Christopher M; Nicholls, Tonia L; Seto, Michael C

    2016-03-01

    The objectives of this study were to describe the disposition and housing trajectories of individuals found Not Criminally Responsible on account of Mental Disorder (NCRMD), and the factors that predict different trajectories. To do so, disposition and housing status were coded for 934 NCRMD patients over a 36-month follow-up period. Sequential data analysis resulted in four distinct trajectories: detention in hospital, conditional discharge in supportive housing, conditional discharge in independent housing, and absolute discharge to unknown housing. The likelihood of a placement in supportive housing compared with detention significantly decreased for individuals with a higher index offense severity. Less restrictive trajectories were significantly predicted by clinical factors. The results revealed little change in the disposition and housing trajectories of NCRMD patients. Furthermore, decisions about disposition and housing placement reflect a knowledge-practice gap between risk factors known to be predictive of community resources use in the forensic population. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Academic Self-Concept, Autonomous Academic Motivation, and Academic Achievement: Mediating and Additive Effects

    ERIC Educational Resources Information Center

    Guay, Frederic; Ratelle, Catherine F.; Roy, Amelie; Litalien, David

    2010-01-01

    Three conceptual models were tested to examine the relationships among academic self-concept, autonomous academic motivation, and academic achievement. This allowed us to determine whether 1) autonomous academic motivation mediates the relation between academic self-concept and achievement, 2) academic self-concept mediates the relation between…

  12. What Is Academic Momentum? and Does It Matter?

    ERIC Educational Resources Information Center

    Attewell, Paul; Heil, Scott; Reisel, Liza

    2012-01-01

    The academic momentum perspective suggests that the speed with which undergraduates initially progress in college significantly affects their likelihood of completing a degree, an effect separate from those of high school academic preparation and family socioeconomic status. Growth curve modeling of undergraduate transcript data reveals that the…

  13. Performance Measurement of Academic Liaison in Higher Education Libraries.

    ERIC Educational Resources Information Center

    Johnson, Hilary

    Academic liaison--the two-way communication between a particular academic area and the library, focused through an individual or group of library staff--has received little attention in the debate about performance measurement. Changes have taken place in higher education libraries in both scale, with the growth of student numbers, and intent,…

  14. Convergence and Professional Identity in the Academic Library

    ERIC Educational Resources Information Center

    Wilson, Kerry M.; Halpin, Eddie

    2006-01-01

    This paper discusses the effects of operational convergence, and the subsequent growth of the hybrid library model, upon the professional self-identity of academic library staff. The role of professionalism as a concept and motivational driver within contemporary academic librarianship is examined. Main themes of investigation include the extent…

  15. Sociodemographic Moderators of Middle School Transition Effects on Academic Achievement

    ERIC Educational Resources Information Center

    Akos, Patrick; Rose, Roderick A.; Orthner, Dennis

    2015-01-01

    The academic impact of the transition from elementary to middle school has significant consequences for many early adolescents. This study examines academic growth across the transition, as well as sociodemographic moderators. Rather than defining the transition effect as a decline in student achievement between fifth and sixth grade, these data…

  16. Mathematical difficulties as decoupling of expectation and developmental trajectories

    PubMed Central

    McLean, Janet F.; Rusconi, Elena

    2014-01-01

    Recent years have seen an increase in research articles and reviews exploring mathematical difficulties (MD). Many of these articles have set out to explain the etiology of the problems, the possibility of different subtypes, and potential brain regions that underlie many of the observable behaviors. These articles are very valuable in a research field, which many have noted, falls behind that of reading and language disabilities. Here will provide a perspective on the current understanding of MD from a different angle, by outlining the school curriculum of England and the US and connecting these to the skills needed at different stages of mathematical understanding. We will extend this to explore the cognitive skills which most likely underpin these different stages and whose impairment may thus lead to mathematics difficulties at all stages of mathematics development. To conclude we will briefly explore interventions that are currently available, indicating whether these can be used to aid the different children at different stages of their mathematical development and what their current limitations may be. The principal aim of this review is to establish an explicit connection between the academic discourse, with its research base and concepts, and the developmental trajectory of abstract mathematical skills that is expected (and somewhat dictated) in formal education. This will possibly help to highlight and make sense of the gap between the complexity of the MD range in real life and the state of its academic science. PMID:24567712

  17. Challenges and perspectives of academic evaluation.

    PubMed

    Bastos, Francisco Inácio P M

    2013-08-01

    Academic evaluation has been an essential component of modern science since its inception, as science has moved away from personalized patronage toward its contemporary role as an essential enterprise of contemporary, democratic societies. In recent years, Brazil has experienced sustained growth in its scientific output, which is nowadays fully compatible with its status as a high middle-income country striving to become a fully developed, more equitable country in the years to come. Growth usually takes place amidst challenges and dilemmas and, in Brazil as elsewhere, academic evaluation is not exempt from such difficulties. In a large, profoundly heterogeneous country with a national evaluation system and nationwide on-line platforms disseminating information on the most disparate fields of knowledge, the main challenges refer to how to pay attention to detail without losing sight of comprehensiveness and how to handle social and regional diversity while preserving academic excellence as the fundamental benchmark.

  18. Freezing Behavior of Stratospheric Sulfate Aerosols Inferred from Trajectory Studies

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Toon, O. B.; Hamill, Patrick

    1995-01-01

    Based on the trajectory analysis presented in this paper, a new mechanism is described for the freezing of the stratospheric sulfate aerosols. Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE-I (1989) and AAOE (1987) are presented. The mechanism requires, as an initial step, the cooling of a H2SO4/H2O aerosol to low temperatures. If a cooling cycle is then followed up by a warming to approximately 196-198 K, the aerosols may freeze due to the growth of the crystallizing embryos formed at the colder temperature. The HNO3 absorbed at colder temperatures may increase the nucleation rate of the crystalling embryos and therefore influence the crystallization of the supercooled aerosols upon warming. Of all the ER-2 flights described, only the polar stratospheric clouds (PSC), observed on the flights of January 24, and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3/H2O (type Ib PSCs). For those two days, back trajectories indicate that the air mass was exposed to sulfuric acid tetrahydrate (SAT) melting temperatures about 24 hours prior to being sampled by the ER-2. Temperature histories, recent laboratory measurements, and the properties of glassy solids suggest that stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at approximately 198 K after going through a cooling cycle to about 194 K or lower.

  19. Parental Work Schedules and Children’s Cognitive Trajectories

    PubMed Central

    Fox, Liana E.

    2011-01-01

    Previous work has shown an association between mothers’ nonstandard work schedules and children’s well-being. We built on this research by examining the relationship between parental shift work and children’s reading and math trajectories from age 5/6 to 13/14. Using data (N=7,105) from the National Longitudinal Survey of Youth and growth curve modeling, we found that children’s math and reading trajectories were related to parents’ type of nonstandard shifts (i.e., evening, night, or variable). We found that having a mother who worked more years at a night shift was associated with lower reading scores, having a mother work more years at evening or night shifts was associated with reduced math trajectories, and having a father work more years at an evening shift was associated with reduced math scores. Mediation tests suggest that eating meals together, parental knowledge about children’s whereabouts, and certain after-school activities might help explain these results. PMID:22058571

  20. Challenges in Achieving Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Cate, Karen Tung

    2012-01-01

    In the past few years much of the global ATM research community has proposed advanced systems based on Trajectory-Based Operations (TBO). The concept of TBO uses four-dimensional aircraft trajectories as the base information for managing safety and capacity. Both the US and European advanced ATM programs call for the sharing of trajectory data across different decision support tools for successful operations. However, the actual integration of TBO systems presents many challenges. Trajectory predictors are built to meet the specific needs of a particular system and are not always compatible with others. Two case studies are presented which examine the challenges of introducing a new concept into two legacy systems in regards to their trajectory prediction software. The first case describes the issues with integrating a new decision support tool with a legacy operational system which overlap in domain space. These tools perform similar functions but are driven by different requirements. The difference in the resulting trajectories can lead to conflicting advisories. The second case looks at integrating this same new tool with a legacy system originally developed as an integrated system, but diverged many years ago. Both cases illustrate how the lack of common architecture concepts for the trajectory predictors added cost and complexity to the integration efforts.

  1. Six Developmental Trajectories Characterize Children With Autism

    PubMed Central

    Fountain, Christine; Winter, Alix S.

    2012-01-01

    OBJECTIVE: The goal of this study was to describe the typical longitudinal developmental trajectories of social and communication functioning in children with autism and to determine the correlates of these trajectories. METHODS: Children with autism who were born in California from 1992 through 2001 and enrolled with the California Department of Developmental Services were identified. Subjects with <4 evaluations present in the database were excluded, resulting in a sample of 6975 children aged 2 to 14 years. Score sequences were constructed based on 9 evaluative items for social, communication, and repetitive behavior functioning. Typical trajectories were identified by using group-based latent trajectory modeling, and multinomial logistic regression models were used to determine the odds of classification within each trajectory varied by individual and family-level factors. RESULTS: Six typical patterns of social, communication, and repetitive behavior functioning were identified. These trajectories displayed significant heterogeneity in developmental pathways, and children whose symptoms were least severe at first diagnosis tended to improve more rapidly than those severely affected. One group of ∼10% of children experienced rapid gains, moving from severely affected to high functioning. Socioeconomic factors were correlated with trajectory outcomes; children with non-Hispanic, white, well-educated mothers were more likely to be high functioning, and minority children with less-educated mothers or intellectual disabilities were very unlikely to experience rapid gains. CONCLUSIONS: Children with autism have heterogeneous developmental pathways. One group of children evidenced remarkable developmental change over time. Understanding what drives these outcomes is thus critical. PMID:22473372

  2. Trajectory Based Behavior Analysis for User Verification

    NASA Astrophysics Data System (ADS)

    Pao, Hsing-Kuo; Lin, Hong-Yi; Chen, Kuan-Ta; Fadlil, Junaidillah

    Many of our activities on computer need a verification step for authorized access. The goal of verification is to tell apart the true account owner from intruders. We propose a general approach for user verification based on user trajectory inputs. The approach is labor-free for users and is likely to avoid the possible copy or simulation from other non-authorized users or even automatic programs like bots. Our study focuses on finding the hidden patterns embedded in the trajectories produced by account users. We employ a Markov chain model with Gaussian distribution in its transitions to describe the behavior in the trajectory. To distinguish between two trajectories, we propose a novel dissimilarity measure combined with a manifold learnt tuning for catching the pairwise relationship. Based on the pairwise relationship, we plug-in any effective classification or clustering methods for the detection of unauthorized access. The method can also be applied for the task of recognition, predicting the trajectory type without pre-defined identity. Given a trajectory input, the results show that the proposed method can accurately verify the user identity, or suggest whom owns the trajectory if the input identity is not provided.

  3. Longitudinal predictors of reading and math trajectories through middle school for African American versus Caucasian students across two samples.

    PubMed

    Hooper, Stephen R; Roberts, Joanne; Sideris, John; Burchinal, Margaret; Zeisel, Susan

    2010-09-01

    This study's primary purpose was to examine the relative contribution of social-behavioral predictors to reading and math skills. The study expands on Duncan et al.'s (2007) work by using longitudinal methodology from the National Institute of Child Health and Human Development's Study of Child Care and Youth Development (SECCYD) and the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K) databases, and by focusing on potential differences in patterns of early predictors of later reading and math trajectories for African American versus Caucasian students. Predictor measures were selected at kindergarten, and the outcomes included standardized reading and math scores obtained from Grades 1, 3, 5, and 9 for the SECCYD sample, and Grades 3, 5, and 8 for the ECLS-K sample. Consistent with Duncan et al.'s findings, results reflect the relative contributions of early reading and math skills to later functioning in these respective academic domains for both samples, and there are indications for the importance of early expressive language skills to both reading and math in the SECCYD sample. Findings related to the power of social-behavioral predictors, however, are not consistent across samples. Although the SECCYD sample evidenced no such predictors, several interactions in the ECLS-K sample suggested the moderating effects of early ratings of aggressive behaviors and internalizing behaviors on later reading and math for African American students. The moderating effects of early teacher ratings of attention and internalizing behaviors for African American students as compared with Caucasian students in later math growth also were noted. The importance of early social-behavioral functions as related to later academic skills remains an important area of inquiry.

  4. The Academic Structure in Japan: Institutional Hierarchy and Academic Mobility.

    ERIC Educational Resources Information Center

    Arimoto, Akira

    The characteristics of the Japanese academic structure are examined with attention to the evolution of institutional hierarchy, the closed academic structure, and the effects of the academic structure upon academic research. The evolution of Japan's institutional hierarchy in academics has been tightly related to factors of nationalism,…

  5. Associations between trajectories of perceived racial discrimination and psychological symptoms among African American adolescents

    PubMed Central

    Smith-Bynum, Mia A.; Lambert, Sharon F.; English, Devin; Ialongo, Nicholas S.

    2014-01-01

    Many African American adolescents experience racial discrimination, with adverse consequences; however, stability and change in these experiences over time have not been examined. We examined longitudinal patterns of perceived racial discrimination assessed in grades 7 – 10 and how these discrimination trajectories related to patterns of change in depressive and anxious symptoms and aggressive behaviors assessed over the same 4-year period. Growth mixture modeling performed on a community epidemiologically-defined sample of urban African American adolescents (n = 504) revealed three trajectories of discrimination: (1) increasing, (2) decreasing, and (3) stable low. As predicted, African American boys were more frequent targets for racial discrimination as they aged, and were more likely to be in the increasing group. Results of parallel process growth mixture modeling revealed that youth in the increasing racial discrimination group were four times more likely to be in an increasing depression trajectory than youth in the low stable discrimination trajectory. Though youth in the increasing racial discrimination group were nearly twice as likely to be in the high aggression trajectory, results were not statistically significant. These results indicate an association between variation in the growth of perceived racial discrimination and youth behavior and psychological well-being over the adolescent years. PMID:24955844

  6. Impacts of Drought Legacies on Tree Demography and Successional Trajectories of Tropical Forests

    NASA Astrophysics Data System (ADS)

    Uriarte, M.; Chazdon, R.; Boukili, V.

    2015-12-01

    Regenerating tropical forests account for 70% of all remaining tropical forest cover and 50% of the terrestrial carbon sink. Despite the importance of successional vegetation in tropical regions for global climate, how inter-annual climate variability influences successional trajectories and biomass accumulation remains poorly understood. Lagged effects of climate extremes on tropical tree demography and successional trajectories represent one key uncertainty. We couple 15 years of climate records and tree growth and survival data with functional trait information for 172 tree species to parameterize Stochastic Antecedent Models (SAMs) of lagged effects of drought on tree demography in second-growth tropical forests in Costa Rica. We also quantify how these legacies influence successional trajectories and biomass accumulation. Drought legacies on tree growth were particularly marked for species with high Specific Leaf Area and low wood density. These legacies led to elevated rates of tree mortality, particularly for large (>10 cm in diameter) up to 4 years after the occurrence of extreme droughts. Simulations of successional trajectories using immediate and lagged drought effects demonstrate that lagged effects lead to shifts in successional trajectories and substantial losses in biomass accumulation.

  7. Associations between trajectories of perceived racial discrimination and psychological symptoms among African American adolescents.

    PubMed

    Smith-Bynum, Mia A; Lambert, Sharon F; English, Devin; Ialongo, Nicholas S

    2014-11-01

    Many African American adolescents experience racial discrimination, with adverse consequences; however, stability and change in these experiences over time have not been examined. We examined longitudinal patterns of perceived racial discrimination assessed in Grades 7-10 and how these discrimination trajectories related to patterns of change in depressive and anxious symptoms and aggressive behaviors assessed over the same 4-year period. Growth mixture modeling performed on a community epidemiologically defined sample of urban African American adolescents (n = 504) revealed three trajectories of discrimination: increasing, decreasing, and stable low. As predicted, African American boys were more frequent targets for racial discrimination as they aged, and they were more likely to be in the increasing group. The results of parallel process growth mixture modeling revealed that youth in the increasing racial discrimination group were four times more likely to be in an increasing depression trajectory than were youth in the low stable discrimination trajectory. Though youth in the increasing racial discrimination group were nearly twice as likely to be in the high aggression trajectory, results were not statistically significant. These results indicate an association between variation in the growth of perceived racial discrimination and youth behavior and psychological well-being over the adolescent years.

  8. Publishing and academic promotion.

    PubMed

    Dixon, A K

    2009-09-01

    Clearly, academic endeavour has to be the single most important criterion for appointment to an academic position and for subsequent promotion. It is rare for excellence either in teaching or clinical practice to offset a poor publication record. However, the pressure to publish and gain related grant income can lead to problems in the normal academic pursuits of a department or institution. These and other related issues will be explored in this editorial.

  9. Soccer ball lift coefficients via trajectory analysis

    NASA Astrophysics Data System (ADS)

    Goff, John Eric; Carré, Matt J.

    2010-07-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  10. Helicopter trajectory planning using optimal control theory

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1988-01-01

    A methodology for optimal trajectory planning, useful in the nap-of-the-earth guidance of helicopters, is presented. This approach uses an adjoint-control transformation along with a one-dimensional search scheme for generating the optimal trajectories. In addition to being useful for helicopter nap-of-the-earth guidance, the trajectory planning solution is of interest in several other contexts, such as robotic vehicle guidance and terrain-following guidance for cruise missiles and aircraft. A distinguishing feature of the present research is that the terrain constraint and the threat envelopes are incorporated in the equations of motion. Second-order necessary conditions are examined.

  11. Mars Ascent Propulsion Trades with Trajectory Analysis

    SciTech Connect

    Whitehead, J

    2004-04-22

    Optimized trajectories to a 500 km circular orbit are calculated for vehicles having a 100 kg Mars launch mass. Staging trades, thrust optimization, and the importance of vehicle shape for drag are all taken into consideration. The high acceleration of solid rockets requires a steep trajectory for drag avoidance, followed by a relatively large circularization burn, appropriate for a second stage. Liquid thrust reduces drag, resulting in less steep trajectories which have small circularization burns. Liquid propulsion requires less total {Delta}v, and offers options for multiple stages or just one. Graphs of payload mass versus stage propellant fractions are compared for liquid and solid propulsion.

  12. An Examination of "The Martian" Trajectory

    NASA Technical Reports Server (NTRS)

    Burke, Laura

    2015-01-01

    This analysis was performed to support a request to examine the trajectory of the Hermes vehicle in the novel "The Martian" by Andy Weir. Weir developed his own tool to perform the analysis necessary to provide proper trajectory information for the novel. The Hermes vehicle is the interplanetary spacecraft that shuttles the crew to and from Mars. It is notionally a Nuclear powered vehicle utilizing VASIMR engines for propulsion. The intent of this analysis was the determine whether the trajectory as it was outlined in the novel is consistent with the rules of orbital mechanics.

  13. The Academic Integrity of Study Abroad.

    ERIC Educational Resources Information Center

    Stryker, Richard E.

    1997-01-01

    If education is intrinsically about learning to cope with change, encouraging personal growth and self-knowledge, and expanding horizons to encompass the wider world, study abroad ought to be part of the undergraduate experience of every student. Financial aid and academic standards belong at the core of institutional efforts to expand overseas…

  14. International Students' Confidence and Academic Success

    ERIC Educational Resources Information Center

    Telbis, Nicola Miky; Helgeson, Lars; Kingsbury, Cheryl

    2014-01-01

    Research shows that the international student population is showing significant growth. This article deals with issues affecting a growing international student population. Studies show that foreign students are encountering difficulties in social adaptability, language barriers, academic ability, and financial need. There is evidence that a…

  15. Student Attitudes on Academic Integrity Violations

    ERIC Educational Resources Information Center

    Baker, Russell K.; Berry, Priscilla; Thornton, Barry

    2008-01-01

    Cheating is a continual dilemma on university campuses, and academic integrity violations have reached epidemic proportions according to current literature. The rapid growth of computer technologies and their application in education has provided unethical students, and otherwise ethical students, with new tools for their cheating activities.…

  16. International Students' Confidence and Academic Success

    ERIC Educational Resources Information Center

    Telbis, Nicola Miky

    2013-01-01

    Research shows that the international student population is showing significant growth. Studies also show that foreign students are encountering difficulties such as social adaptability, language barriers, academic ability, and financial need. There is compelling evidence that establishes a correlation between a person's self-efficacy and his or…

  17. Ascent trajectory dispersion analysis for WTR heads-up space shuttle trajectory

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The results of a Space Transportation System ascent trajectory dispersion analysis are discussed. The purpose is to provide critical trajectory parameter values for assessing the Space Shuttle in a heads-up configuration launched from the Western Test Range (STR). This analysis was conducted using a trajectory profile based on a launch from the WTR in December. The analysis consisted of the following steps: (1) nominal trajectories were simulated under the conditions as specified by baseline reference mission guidelines; (2) dispersion trajectories were simulated using predetermined parametric variations; (3) requirements for a system-related composite trajectory were determined by a root-sum-square (RSS) analysis of the positive deviations between values of the aerodynamic heating indicator (AHI) generated by the dispersion and nominal trajectories; (4) using the RSS assessment as a guideline, the system related composite trajectory was simulated by combinations of dispersion parameters which represented major contributors; (5) an assessment of environmental perturbations via a RSS analysis was made by the combination of plus or minus 2 sigma atmospheric density variation and 95% directional design wind dispersions; (6) maximum aerodynamic heating trajectories were simulated by variation of dispersion parameters which would emulate the summation of the system-related RSS and environmental RSS values of AHI. The maximum aerodynamic heating trajectories were simulated consistent with the directional winds used in the environmental analysis.

  18. The Hungry Mind: Intellectual Curiosity Is the Third Pillar of Academic Performance.

    PubMed

    von Stumm, Sophie; Hell, Benedikt; Chamorro-Premuzic, Tomas

    2011-11-01

    Over the past century, academic performance has become the gatekeeper to institutions of higher education, shaping career paths and individual life trajectories. Accordingly, much psychological research has focused on identifying predictors of academic performance, with intelligence and effort emerging as core determinants. In this article, we propose expanding on the traditional set of predictors by adding a third agency: intellectual curiosity. A series of path models based on a meta-analytically derived correlation matrix showed that (a) intelligence is the single most powerful predictor of academic performance; (b) the effects of intelligence on academic performance are not mediated by personality traits; (c) intelligence, Conscientiousness (as marker of effort), and Typical Intellectual Engagement (as marker of intellectual curiosity) are direct, correlated predictors of academic performance; and (d) the additive predictive effect of the personality traits of intellectual curiosity and effort rival that the influence of intelligence. Our results highlight that a "hungry mind" is a core determinant of individual differences in academic achievement.

  19. Partnerships with Academic Departments

    ERIC Educational Resources Information Center

    English, Anthony M.

    2013-01-01

    This chapter describes how professional and continuing higher education units can develop and sustain successful partnerships with academic departments in order to deliver educational programs effectively to students.

  20. Analysis of flight trajectories of a ramjet-powered vehicle

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Aulchenko, S. M.; Zvegintsev, V. I.; Ustinov, L. A.

    2014-11-01

    Based on numerical simulations of flight trajectories with ramjet-powered flying vehicles, it is found that all possible flight trajectories can be classified into three groups: ballistic trajectories, trajectories with a horizontal segment, and skipping trajectories. Trajectories of each group can be optimized, for instance, to ensure the maximum flight range under given initial conditions and constraints. Examples of optimal trajectories for a given amount of available fuel are presented as functions of the initial slope of the trajectory, angle of attack of the vehicle, instants of engine actuation, and engine operation time.

  1. Reinventing the academic health center.

    PubMed

    Kirch, Darrell G; Grigsby, R Kevin; Zolko, Wayne W; Moskowitz, Jay; Hefner, David S; Souba, Wiley W; Carubia, Josephine M; Baron, Steven D

    2005-11-01

    Academic health centers have faced well-documented internal and external challenges over the last decade, putting pressure on organizational leaders to develop new strategies to improve performance while simultaneously addressing employee morale, patient satisfaction, educational outcomes, and research growth. In the aftermath of a failed merger, new leaders of The Pennsylvania State University College of Medicine and Milton S. Hershey Medical Center encountered a climate of readiness for a transformational change. In a case study of this process, nine critical success factors are described that contributed to significant performance improvement: performing a campus-wide cultural assessment and acting decisively on the results; making values explicit and active in everyday decisions; aligning corporate structure and governance to unify the academic enterprise and health system; aligning the next tier of administrative structure and function; fostering collaboration and accountability-the creation of unified campus teams; articulating a succinct, highly focused, and compelling vision and strategic plan; using the tools of mission-based management to realign resources; focusing leadership recruitment on organizational fit; and "growing your own" through broad-based leadership development. Outcomes assessment data for academic, research, and clinical performance showed significant gains between 2000 and 2004. Organizational transformation as a result of the nine factors is possible in other institutional settings and can facilitate a focus on crucial quality initiatives.

  2. Personality development from adolescence to emerging adulthood: linking trajectories of ego development to the family context and identity formation.

    PubMed

    Syed, Moin; Seiffge-Krenke, Inge

    2013-02-01

    This longitudinal study analyzed personality development using an individual approach by examining changes in ego development across the transition from adolescence to emerging adulthood. Specifically, the study mapped the heterogeniety in ego development growth trajectories and linked the different trajectories to the family context in adolescence and identity development in emerging adulthood. Participants were 98 families with a child who were followed from age 14 to age 24. Latent class growth analysis identified 4 distinct trajectories of growth in ego development of the children over the 10-year period. The results indicated that growth was more rapid during adolescence and tended to taper off in emerging adulthood. In addition, promotion of personal growth within the family and parents' ego development were particulary instrumental in children's ego developmental gains in adolescence. Finally, youth who demonstrated continued ego development into emerging adulthood also demonstrated heightened levels of identity exploration.

  3. Longitudinal trajectories of ethnic identity among urban Black and Latino adolescents.

    PubMed

    Pahl, Kerstin; Way, Niobe

    2006-01-01

    The current study modeled developmental trajectories of ethnic identity exploration and affirmation and belonging from middle to late adolescence (ages 15-18) and examined how these trajectories varied according to ethnicity, gender, immigrant status, and perceived level of discrimination. The sample consisted of 135 urban low-income Black and Latino adolescents (42% male, 34% Black, 66% Latino). Consistent with developmental theory, individual growth modeling identified an average quadratic trajectory of ethnic identity exploration characterized by decelerating levels of exploration after 10th grade. However, ethnicity and perceived discrimination by peers moderated this pattern. No uniform growth pattern in affirmation was found and Black and Latino adolescents displayed equally high levels of affirmation over time.

  4. Algorithm for fuel conservative horizontal capture trajectories

    NASA Technical Reports Server (NTRS)

    Neuman, F.; Erzberger, H.

    1981-01-01

    A real time algorithm for computing constant altitude fuel-conservative approach trajectories for aircraft is described. The characteristics of the trajectory computed were chosen to approximate the extremal trajectories obtained from the optimal control solution to the problem and showed a fuel difference of only 0.5 to 2 percent for the real time algorithm in favor of the extremals. The trajectories may start at any initial position, heading, and speed and end at any other final position, heading, and speed. They consist of straight lines and a series of circular arcs of varying radius to approximate constant bank-angle decelerating turns. Throttle control is maximum thrust, nominal thrust, or zero thrust. Bank-angle control is either zero or aproximately 30 deg.

  5. Trajectory of the index finger during grasping.

    PubMed

    Friedman, Jason; Flash, Tamar

    2009-07-01

    The trajectory of the index finger during grasping movements was compared to the trajectories predicted by three optimization-based models. The three models consisted of minimizing the integral of the weighted squared joint derivatives along the path (inertia-like cost), minimizing torque change, and minimizing angular jerk. Of the three models, it was observed that the path of the fingertip and the joint trajectories, were best described by the minimum angular jerk model. This model, which does not take into account the dynamics of the finger, performed equally well when the inertia of the finger was altered by adding a 20 g weight to the medial phalange. Thus, for the finger, it appears that trajectories are planned based primarily on kinematic considerations at a joint level.

  6. Trajectories of Alcohol Consumption Following Liver Transplantation

    PubMed Central

    DiMartini, Andrea; Dew, Mary Amanda; Day, Nancy; Fitzgerald, Mary Grace; Jones, Bobby L.; deVera, Michael; Fontes, Paulo

    2010-01-01

    Any use of alcohol in the years following liver transplantation (LTX) approaches 50% of patients transplanted for alcoholic liver disease (ALD). We collected detailed prospective data on alcohol consumption following LTX for ALD to investigate ongoing patterns of use. Using trajectory modeling we identified four distinct alcohol use trajectories. One group had minimal use over time. Two other groups developed early onset moderate to heavy consumption and one group developed late onset moderate use. These trajectories demonstrate that alcohol use varies based on timing of onset, quantity, and duration. Using discriminant function analysis, we examine characteristics of recipient’s pre-LTX alcohol histories and early post-LTX psychological stressors to identify the profile of those at risk for these specific trajectories. We discuss the relevance of these findings to clinical care and preliminarily to outcomes. PMID:20726963

  7. Goddard trajectory determination subsystem: Mathematical specifications

    NASA Technical Reports Server (NTRS)

    Wagner, W. E. (Editor); Velez, C. E. (Editor)

    1972-01-01

    The mathematical specifications of the Goddard trajectory determination subsystem of the flight dynamics system are presented. These specifications include the mathematical description of the coordinate systems, dynamic and measurement model, numerical integration techniques, and statistical estimation concepts.

  8. Algorithm for fixed-range optimal trajectories

    NASA Technical Reports Server (NTRS)

    Lee, H. Q.; Erzberger, H.

    1980-01-01

    An algorithm for synthesizing optimal aircraft trajectories for specified range was developed and implemented in a computer program written in FORTRAN IV. The algorithm, its computer implementation, and a set of example optimum trajectories for the Boeing 727-100 aircraft are described. The algorithm optimizes trajectories with respect to a cost function that is the weighted sum of fuel cost and time cost. The optimum trajectory consists at most of a three segments: climb, cruise, and descent. The climb and descent profiles are generated by integrating a simplified set of kinematic and dynamic equations wherein the total energy of the aircraft is the independent or time like variable. At each energy level the optimum airspeeds and thrust settings are obtained as the values that minimize the variational Hamiltonian. Although the emphasis is on an off-line, open-loop computation, eventually the most important application will be in an on-board flight management system.

  9. Numerical Calculation of Model Rocket Trajectories.

    ERIC Educational Resources Information Center

    Keeports, David

    1990-01-01

    Discussed is the use of model rocketry to teach the principles of Newtonian mechanics. Included are forces involved; calculations for vertical launches; two-dimensional trajectories; and variations in mass, drag, and launch angle. (CW)

  10. Trajectory tracking control for underactuated stratospheric airship

    NASA Astrophysics Data System (ADS)

    Zheng, Zewei; Huo, Wei; Wu, Zhe

    2012-10-01

    Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

  11. The Trajectories of Saccadic Eye Movements.

    ERIC Educational Resources Information Center

    Bahill, A. Terry; Stark, Lawrence

    1979-01-01

    Investigates the trajectories of saccadic eye movements, the control signals of the eye, and nature of the mechanisms that generate them, using the techniques of bioengineering in collecting the data. (GA)

  12. Trajectory Browser: An Online Tool for Interplanetary Trajectory Analysis and Visualization

    NASA Technical Reports Server (NTRS)

    Foster, Cyrus James

    2013-01-01

    The trajectory browser is a web-based tool developed at the NASA Ames Research Center for finding preliminary trajectories to planetary bodies and for providing relevant launch date, time-of-flight and (Delta)V requirements. The site hosts a database of transfer trajectories from Earth to planets and small-bodies for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and (Delta)V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies.

  13. Perceived Social Support Trajectories and the All-Cause Mortality Risk of Older Mexican American Women and Men

    PubMed Central

    Hill, Terrence D.; Uchino, Bert N.; Eckhardt, Jessica L.; Angel, Jacqueline L.

    2016-01-01

    Although numerous studies of non-Hispanic whites and blacks show that social integration and social support tend to favor longevity, it is unclear whether this general pattern extends to the Mexican American population. Building on previous research, we employed seven waves of data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly to examine the association between perceived social support trajectories and the all-cause mortality risk of older Mexican Americans. Growth mixture estimates revealed three latent classes of support trajectories: high, moderate, and low. Cox regression estimates indicated that older Mexican American men in the low support trajectory tend to exhibit a higher mortality risk than their counterparts in the high support trajectory. Social support trajectories were unrelated to the mortality risk of older Mexican American women. A statistically significant interaction term confirmed that social support was more strongly associated with the mortality risk of men. PMID:26966256

  14. Perceived Social Support Trajectories and the All-Cause Mortality Risk of Older Mexican American Women and Men.

    PubMed

    Hill, Terrence D; Uchino, Bert N; Eckhardt, Jessica L; Angel, Jacqueline L

    2016-04-01

    Although numerous studies of non-Hispanic Whites and Blacks show that social integration and social support tend to favor longevity, it is unclear whether this general pattern extends to the Mexican American population. Building on previous research, we employed seven waves of data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly to examine the association between perceived social support trajectories and the all-cause mortality risk of older Mexican Americans. Growth mixture estimates revealed three latent classes of support trajectories: high, moderate, and low. Cox regression estimates indicated that older Mexican American men in the low support trajectory tend to exhibit a higher mortality risk than their counterparts in the high support trajectory. Social support trajectories were unrelated to the mortality risk of older Mexican American women. A statistically significant interaction term confirmed that social support was more strongly associated with the mortality risk of men.

  15. Trajectory options for the DART mission

    NASA Astrophysics Data System (ADS)

    Atchison, Justin A.; Ozimek, Martin T.; Kantsiper, Brian L.; Cheng, Andrew F.

    2016-06-01

    This study presents interplanetary trajectory options for the Double Asteroid Redirection Test (DART) spacecraft to reach the near Earth object, Didymos binary system, during its 2022 Earth conjunction. DART represents a component of a joint NASA-ESA mission to study near Earth object kinetic impact deflection. The DART trajectory must satisfy mission objectives for arrival timing, geometry, and lighting while minimizing launch vehicle and spacecraft propellant requirements. Chemical propulsion trajectories are feasible from two candidate launch windows in late 2020 and 2021. The 2020 trajectories are highly perturbed by Earth's orbit, requiring post-launch deep space maneuvers to retarget the Didymos system. Within these windows, opportunities exist for flybys of additional near Earth objects: Orpheus in 2021 or 2007 YJ in 2022. A second impact attempt, in the event that the first impact is unsuccessful, can be added at the expense of a shorter launch window and increased (∼3x) spacecraft ΔV . However, the second impact arrival geometry has poor lighting, high Earth ranges, and would require additional degrees of freedom for solar panel and/or antenna gimbals. A low-thrust spacecraft configuration increases the trajectory flexibility. A solar electric propulsion spacecraft could be affordably launched as a secondary spacecraft in an Earth orbit and spiral out to target the requisite interplanetary departure condition. A sample solar electric trajectory was constructed from an Earth geostationary transfer using a representative 1.5 kW thruster. The trajectory requires 9 months to depart Earth's sphere of influence, after which its interplanetary trajectory includes a flyby of Orpheus and a second Didymos impact attempt. The solar electric spacecraft implementation would impose additional bus design constraints, including large solar arrays that could pose challenges for terminal guidance. On the basis of this study, there are many feasible options for DART to

  16. Filtering Drifter Trajectories Sampled at Submesoscale Resolution

    DTIC Science & Technology

    2015-05-11

    40, NO. 3, JULY 2015 497 Filtering Drifter Trajectories Sampled at Submesoscale Resolution Max Yaremchuk and Emanuel F. Coelho Abstract—In this paper...accel- erations while keeping the difference between the filtered and ob- served trajectories within the error bars of the positioning noise...Mexico in 2012. Index Terms—Computers and information processing/data pro- cessing,mathematics/ filtering algorithms, optimization, smoothing methods

  17. Optimizing Simulated Trajectories Of Rigid Bodies

    NASA Technical Reports Server (NTRS)

    Brauer, Garry L.; Olson, David W.; Stevenson, Robert

    1989-01-01

    6D POST is general-purpose, six-degree-of-freedom computer program for optimization of simulated trajectories of rigid bodies. Direct extension of three-degree-of-freedom POST program. 6D POST program models trajectory of powered or unpowered vehicle operating at or near rotating planet. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Written in FORTRAN 77 and FORTRAN V.

  18. Systematic Disturbance Of Optimal Rotational Trajectory

    NASA Technical Reports Server (NTRS)

    Grunwald, Arthur J.; Kaiser, Mary K.

    1992-01-01

    Algorithm introduces systematic disturbance into otherwise optimal rotation of body from prescribed initial to prescribed final orientation. Disturbance introduced as deviation of actual axis of rotation from optimal one, like wobble of top. Algorithm effects rotational transformations and solves differential equations necessary to compute disturbed trajectory. Devised for use with motion-control program and three-dimensional computer-graphical display to study ability of observers to distinguish between optimal and suboptimal rotational trajectories.

  19. Machine Learning for Biological Trajectory Classification Applications

    NASA Technical Reports Server (NTRS)

    Sbalzarini, Ivo F.; Theriot, Julie; Koumoutsakos, Petros

    2002-01-01

    Machine-learning techniques, including clustering algorithms, support vector machines and hidden Markov models, are applied to the task of classifying trajectories of moving keratocyte cells. The different algorithms axe compared to each other as well as to expert and non-expert test persons, using concepts from signal-detection theory. The algorithms performed very well as compared to humans, suggesting a robust tool for trajectory classification in biological applications.

  20. Characterizing Resilience and Growth Among Soldiers: A Trajectory Study

    DTIC Science & Technology

    2014-04-01

    positive affect, and optimism; flexible attitude; problem-focused coping strategies with stress; social and family support; and life meaning. These...are following: 1) completed follow-up survey data collection, 2) hired research assistants and provided training, 3) developed data management ...University 5 of Michigan and HRPO (see Appendix), 7) attended data analyses workshops on longitudinal data analyses and data management , 8) presented

  1. Characterizing Resilience and Growth Among Soldiers: A Trajectory Study

    DTIC Science & Technology

    2012-04-01

    Outcome Change from Wave 1 to Wave 3 Standardized Beta Coefficient* Wave 2 Predictor Life satisfaction Depression PTSD Emotion 8...4 Key Research Accomplishments………………………………………….…….. 5 Reportable Outcomes ……………………………………………………………… 14 Conclusion... training programs in the military that are conceptually-grounded and empirically-informed. Body At the initial stage of our project, our

  2. Corporal punishment and the growth trajectory of children's antisocial behavior.

    PubMed

    Grogan-Kaylor, Andrew

    2005-08-01

    Despite considerable research, the relationship between corporal punishment and antisocial behavior is unclear. This analysis examined (a) the functional form of this relationship, (b) the correlation of initial antisocial behavior and changes in antisocial behavior, (c) differences in the relationship of corporal punishment and antisocial behavior by race, and (d) whether this relationship could be accounted for by unmeasured characteristics of children and their families. Data from 6,912 children in the National Longitudinal Survey of Youth were analyzed using hierarchical linear models. Findings suggested that corporal punishment has a relationship with children's initial antisocial behavior and with changes in antisocial behavior. No evidence was found for differences in the effect of corporal punishment across racial groups. The relationship between corporal punishment and antisocial behavior persists even when accounting for unmeasured time invariant characteristics of children and families. The findings suggest that corporal punishment is not a preferable technique for disciplining children.

  3. Growth Trajectories of Mexican-Origin Adolescent Mothers' Educational Expectations

    ERIC Educational Resources Information Center

    Bravo, Diamond Y.; Toomey, Russell B.; Umaña-Taylor, Adriana J.; Updegraff, Kimberly A.; Jahromi, Lauden B.

    2017-01-01

    Pregnant and parenting adolescents are at significant risk for educational underachievement. Educational expectations play a critical role for understanding subsequent educational attainment; yet, limited empirical attention has been given to changes in educational expectations across the transition to parenthood among adolescent mothers. This…

  4. Modeling phenotypic plasticity in growth trajectories: a statistical framework.

    PubMed

    Wang, Zhong; Pang, Xiaoming; Wu, Weimiao; Wang, Jianxin; Wang, Zuoheng; Wu, Rongling

    2014-01-01

    Phenotypic plasticity, that is multiple phenotypes produced by a single genotype in response to environmental change, has been thought to play an important role in evolution and speciation. Historically, knowledge about phenotypic plasticity has resulted from the analysis of static traits measured at a single time point. New insight into the adaptive nature of plasticity can be gained by an understanding of how organisms alter their developmental processes in a range of environments. Recent advances in statistical modeling of functional data and developmental genetics allow us to construct a dynamic framework of plastic response in developmental form and pattern. Under this framework, development, genetics, and evolution can be synthesized through statistical bridges to better address how evolution results from phenotypic variation in the process of development via genetic alterations.

  5. Twenty-First Century Academic Feminism in the United States: Utopian Visions and Practical Actions.

    ERIC Educational Resources Information Center

    Laslett, Barbara; Brenner, Johanna

    2000-01-01

    Academic feminists must confront class structure within the academy and women's studies. Changes in the academic work environment include: funding cuts, rapid growth of non-tenure-track faculty, and overproduction of Ph.D.s relative to jobs available (which exemplifies the class structure of academic feminists). Education is a social institution,…

  6. Mars interplanetary trajectory design via Lagrangian points

    NASA Astrophysics Data System (ADS)

    Eapen, Roshan Thomas; Sharma, Ram Krishan

    2014-09-01

    With the increase in complexities of interplanetary missions, the main focus has shifted to reducing the total delta-V for the entire mission and hence increasing the payload capacity of the spacecraft. This paper develops a trajectory to Mars using the Lagrangian points of the Sun-Earth system and the Sun-Mars system. The whole trajectory can be broadly divided into three stages: (1) Trajectory from a near-Earth circular parking orbit to a halo orbit around Sun-Earth Lagrangian point L2. (2) Trajectory from Sun-Earth L2 halo orbit to Sun-Mars L1 halo orbit. (3) Sun-Mars L1 halo orbit to a circular orbit around Mars. The stable and unstable manifolds of the halo orbits are used for halo orbit insertion. The intermediate transfer arcs are designed using two-body Lambert's problem. The total delta-V for the whole trajectory is computed and found to be lesser than that for the conventional trajectories. For a 480 km Earth parking orbit, the total delta-V is found to be 4.6203 km/s. Another advantage in the present approach is that delta-V does not depend upon the synodic period of Earth with respect to Mars.

  7. A method for balloon trajectory control

    NASA Astrophysics Data System (ADS)

    Aaron, K. M.; Heun, M. K.; Nock, K. T.

    A balloon trajectory control system is discussed that is under development for use on NASA's Ultra Long Duration Balloon Project. The trajectory control system exploits the natural wind field variation with altitude to generate passive lateral control forces on a balloon using a tether-deployed aerodynamic surface below the balloon. A lifting device, such as a wing on end, is suspended on a tether well beneath the balloon to take advantage of this variation in wind velocity with altitude. The wing generates a horizontal lift force that can be directed over a wide range of angles. This force, transmitted to the balloon by a tether, alters the balloon's path providing a bias velocity of a few meters per second to the balloon drift rate. The trajectory control system enables the balloon to avoid hazards, reach targets, steer around avoidance countries and select convenient landing zones. No longer will balloons be totally at the mercy of the winds. Tests in April 1999 of a dynamically-scaled model of the trajectory control system were carried out by Global Aerospace Corporation in ground level winds up to 15 m/s. The size of the scale model was designed to simulate the behavior of the full scale trajectory control system operating at 20 km altitude. The model confirmed many aspects of trajectory control system performance and the results will be incorporated into future development.

  8. A demonstration and evaluation of trajectory mapping

    SciTech Connect

    Morris, G.A.

    1994-09-01

    Problem of creating synoptic maps from asynoptically gathered data has prompted the development of a number schemes, the most notable being the Kalman filter, Salby-Fourier technique, and constituent reconstruction. This thesis presents a new technique, called trajectory mapping, which employs a simple model of air parcel motion to create synoptic maps from asynoptically gathered data. Four sources of trajectory mapping errors were analyzed; results showed that (1) the computational error is negligible; (2) measurement uncertainties can result in errors which grow with time scales of a week; (3) isentropic approximations lead to errors characterized by time scales of a week; and (4) wind field inaccuracies can cause significant errors in individual parcel trajectories in a matter of hours. All the studies, however, indicated that while individual trajectory errors can grow rapidly, constituent distributions, such as on trajectory maps, are much more robust, maintaining a high level of accuracy for periods on the order of several weeks. This technique was successfully applied to a variety of problems:(1) dynamical wave- breaking events; (2) satellite data validation for both instrument accuracy and precision; and (3) accuracy of meteorological wind fields. Such demonstrations imply that trajectory mapping will become an important tool in answering questions of global change, particularly the issue of ozone depletion.

  9. A Study of Shuttlecock's Trajectory in Badminton.

    PubMed

    Chen, Lung-Ming; Pan, Yi-Hsiang; Chen, Yung-Jen

    2009-01-01

    The main purpose of this study was to construct and validate a motion equation for the flight of the badminton and to find the relationship between the air resistance force and a shuttlecock's speed. This research method was based on motion laws of aerodynamics. It applied aerodynamic theories to construct motion equation of a shuttlecock's flying trajectory under the effects of gravitational force and air resistance force. The result showed that the motion equation of a shuttlecock's flight trajectory could be constructed by determining the terminal velocity. The predicted shuttlecock trajectory fitted the measured data fairly well. The results also revealed that the drag force was proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. Finally, this study suggested that we could use a scientific approach to measure a shuttlecock's velocity objectively when testing the quality of shuttlecocks. And could be used to replace the traditional subjective method of the Badminton World Federation based on players' striking shuttlecocks, as well as applying research findings to improve professional knowledge of badminton player training. Key pointsThe motion equation of a shuttlecock's flying trajectory could be constructed by determining the terminal velocity in aerodynamics.Air drag force is proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory.

  10. Optimizing interplanetary trajectories with deep space maneuvers

    NASA Astrophysics Data System (ADS)

    Navagh, John

    1993-09-01

    Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

  11. Academic Women in Protest.

    ERIC Educational Resources Information Center

    Theodore, Athena

    This paper is an exploratory inquiry into some aspects of protest for sex equality by academic women. The analysis is based on published and unpublished information on sex discrimination in academia, as well as a sample of 65 cases of academic women obtained from a pilot survey. Following introductory material, Part II emphasizes patterns of…

  12. Thinking Academic Freedom

    ERIC Educational Resources Information Center

    Lange, Lis

    2016-01-01

    This lecture argues that the politicisation and instrumentalisation of the university caused by neoliberal frames has as a result the depoliticisation of knowledge and of the academic as individual. This depoliticisation has turned academic freedom into a right to disengage not only from the political fight around these issues but also from the…

  13. Leaving the Academic Library

    ERIC Educational Resources Information Center

    Luzius, Jeff; Ard, Allyson

    2006-01-01

    A survey was distributed to former academic librarians to determine why they left the field and which career they pursued afterward. Results suggest that former academic librarians are unhappy with administration, image, and salary. Time spent as librarians helped individuals in their new careers.

  14. Impulsivity and Academic Cheating

    ERIC Educational Resources Information Center

    Anderman, Eric M.; Cupp, Pamela K.; Lane, Derek

    2009-01-01

    The authors examined the relations between academic cheating and impulsivity in a large sample of adolescents enrolled in high school health education classes. Results indicated that impulsivity predicts academic cheating for students who report extensive involvement in cheating. However, students who engage in extensive cheating are less likely…

  15. Understanding Academic Confidence

    ERIC Educational Resources Information Center

    Sander, Paul; Sanders, Lalage

    2006-01-01

    This paper draws on the psychological theories of self-efficacy and the self-concept to understand students' self-confidence in academic study in higher education as measured by the Academic Behavioural Confidence scale (ABC). In doing this, expectancy-value theory and self-efficacy theory are considered and contrasted with self-concept and…

  16. Marketing Academic Libraries

    ERIC Educational Resources Information Center

    Mallon, Melissa, Ed.

    2013-01-01

    Ask any academic librarian if marketing their library and its services is an important task, and the answer will most likely be a resounding "yes!" Particularly in economically troubled times, librarians are increasingly called upon to promote their services and defend their library's worth. Since few academic libraries have in-house marketing…

  17. Academic Freedom Revisited

    ERIC Educational Resources Information Center

    Doughty, Howard A.

    2010-01-01

    One of the author's enduring concerns about the concept of academic freedom is with semantics. It has seemed to him that one of the biggest difficulties with discussions of academic freedom (as with many conversations about "value-laden" terms such as "democracy," "equity," and "justice") is that people begin from different positions and with…

  18. The Academic Generation Gap

    ERIC Educational Resources Information Center

    Dronzek, Anna

    2008-01-01

    The current generation gap in academia is different--fundamentally shaped by the structural problems of academic employment. The job market has especially exacerbated tensions between senior and junior faculty by ratcheting up expectations and requirements at every stage of the academic career. The disparities have been mentioned often enough to…

  19. Becoming an Academic Researcher

    ERIC Educational Resources Information Center

    Angervall, Petra; Gustafsson, Jan

    2014-01-01

    The neo-liberal restructuring of academia justifies research concerning what constitutes academic work, what it means to be an academic researcher and how researchers manoeuvre in academia. The aim of this article is to investigate how this reshaping of higher education affects how research careers are formed and impacts on "becoming…

  20. Recalibrating Academic Bias

    ERIC Educational Resources Information Center

    Yancey, George

    2012-01-01

    Whether political and/or religious academic bias exists is a question with important ramifications for the educational institutions. Those arguing for the presence of such bias contend that political conservatives and the highly religious in academia are marginalized and face discrimination. The question of academic bias tends to be cast in a…