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Longitudinal Sample (longitudinal + sample)
Selected AbstractsAn Investigation of FRAXA Intermediate Allele Phenotype in A Longitudinal SampleANNALS OF HUMAN GENETICS, Issue 2 2006S. Ennis Abstract The FRAXA trinucleotide repeat at Xq27.3 gives rise to fragile X syndrome when fully expanded, and both premature ovarian failure (POF) and fragile X tremor and ataxia syndrome (FXTAS) when in the premutation range. Reports of phenotypic effects extending into the intermediate repeat range are inconsistent but some studies suggest that these smaller expansions predispose to special educational needs (SEN). This study utilises the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort to investigate cognitive and behavioural variables that might be associated with FRAXA intermediate alleles. The current study failed to find any strong evidence of association of FRAXA intermediate alleles with SEN, behavioural problems or cognitive difficulties. However, our findings illustrate some of the difficulties encountered in identifying individuals with SEN. The power to identify specific components of cognitive and behavioural difficulties was reduced due to elective drop-out, which is characteristic of longitudinal studies. Our findings demonstrate the non-random loss of participants from this cohort and highlight problems that may arise when such data are used in genetic association studies. [source] The Effect of Venture Capital Financing on the Sensitivity to Cash Flow of Firm's InvestmentsEUROPEAN FINANCIAL MANAGEMENT, Issue 4 2010Fabio Bertoni G32; D92; G23 Abstract This work studies the effect of venture capital (VC) financing on firms' investments in a longitudinal sample of 379 Italian unlisted new-technology-based firms (NTBFs) observed over the 10-year period from 1994 to 2003. We distinguish the effects of VC financing according to the type of investor: independent VC (IVC) funds and corporate VC (CVC) investors. Previous studies argue that NTBFs are the firms most likely to be financially constrained. The technology-intensive nature of their activity and their lack of a track record increase adverse selection and moral hazard problems. Moreover, most of their assets are firm-specific or intangible and hence cannot be pledged as collateral. In accordance with this view, we show that the investment rate of NTBFs is strongly positively correlated with their current cash flows. We also find that after receiving VC financing, NTBFs increase their investment rate independently of the type of VC investor. However, the investments of CVC-backed firms remain sensitive to shocks in cash flows, whereas IVC-backed firms exhibit a low and statistically not significant investment,cash flow sensitivity that we interpret as a signal of the removal of financial constraints. [source] Determining the probability of future smoking among adolescentsADDICTION, Issue 2 2001Won S. Choi Aims. To determine whether the probability of future current established smoking among adolescents is related to both previous smoking experience and cognitions regarding future smoking. Design, setting and participants. The analyses used two principal datasets: (1) a US longitudinal sample of 7960 adolescents 12-18 years old in 1989 reinterviewed at 15-22 years in 1993, (2) a California longitudinal sample of 3376 adolescents 12-17 years old in 1993 reinterviewed at 15-20 years in 1996. Measures. Previous smoking experience was categorized as never smoked, puffed, non-recent or recent experimenting, and non-recent or current established smoking (, 100 cigarettes in life-time). Smoking intentions and efficacy expectations were used to classify adolescents as having low- or high-risk cognitions. Findings. High-risk cognitions (HRCs) increased the probability of future current established smoking (FCES) within each level of previous smoking experience over low-risk cognitions (LRCs); the probability of FCES for those with LRCs was about the same as those in the previous experience group with HRCs. In the US sample, the 4-year probability of FCES ranged from 5.6% for committed never smokers (with LRCs) to 83.0% for current established smokers with HRCs. Development of HRCs among middle-school never smokers occurred rapidly through age 14 years. However, current established smoking did not increase until age 14 years and stabilized by age 19 years. Where sample size was sufficient, these findings were validated in the California sample. Conclusions. Effective prevention programs should aim to convert HRCs to LRCs regardless of past behavior, particularly among middle-school never smokers and high-school experimenters. [source] Right-wing authoritarianism and social dominance orientation and the dimensions of generalized prejudice: A longitudinal testEUROPEAN JOURNAL OF PERSONALITY, Issue 4 2010Frank Asbrock Abstract A Dual Process Model (DPM) approach to prejudice proposes that there should be at least two dimensions of generalized prejudice relating to outgroup stratification and social perception, which should be differentially predicted by Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO). The current study assessed the causal effects of SDO and RWA on three dimensions of prejudice using a full cross-lagged longitudinal sample (N,=,127). As expected, RWA, but not SDO, predicted prejudice towards ,dangerous' groups, SDO, but not RWA, predicted prejudice towards ,derogated' groups, and both RWA and SDO predicted prejudice towards ,dissident' groups. Results support previously untested causal predictions derived from the DPM and indicate that different forms of prejudice result from different SDO- and RWA-based motivational processes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Stability and change in adolescents' personality: a longitudinal studyEUROPEAN JOURNAL OF PERSONALITY, Issue 6 2006Helle Pullmann Abstract The present study examined three types of personality change and continuity (mean-level, individual-level, and rank-order stability) over the 2-year period in a nationally representative longitudinal sample of Estonian adolescents (N,=,876) aged 12,18. According to the Reliable Change Index, 82.1% of adolescents maintained the same level on any given personality trait measured by the NEO Five-Factorial Inventory (NEO-FFI) indicating that the individual-level continuity of adolescents did not differ compared to young adults. A reliable increase was found in Openness. Across the five dimensions, the average test,retest correlations were 0.51, 0.56 and 0.67, and the computed biennial stability values were 0.80, 0.83 and 0.89 for age groups 12,,,14, 14,,,16 and 16,,,18 years, respectively. Neither intelligence nor school performance moderated the differential continuity. Copyright © 2006 John Wiley & Sons, Ltd. [source] The behaviour style observation system for young children predicts teacher-reported externalizing behaviour in middle childhoodINFANT AND CHILD DEVELOPMENT, Issue 4 2009Alexa Martin-Storey Abstract The Behaviour Style Observation System for Young Children (BSOS) was used to predict preschool-aged children's externalizing and internalizing behaviour problems in middle childhood, 3,5 years after the initial assessment. This observational measurement tool was designed to sample and assess young children's disruptive, non-compliant, and unresponsive behaviour, during a brief (11,min) observation in the child's home. In the current study, the BSOS was used to predict parent and teacher ratings of child behaviour problems after school entry in a longitudinal sample (N=81) of at-risk children at time 2. The BSOS predicted teacher-reported externalizing problems at time 2. In contrast, parent reports of behaviour problems, although correlated with repeated parent reports at time 2, were not significantly predictive of teacher-reported behaviour problems at school age. The BSOS was not associated with either parent or teacher reports of internalizing problems. These findings emphasize the importance and utility of using observational measures when examining the continuity of behaviour problems in young children over time. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dynamic treatment effect analysis of TV effects on child cognitive developmentJOURNAL OF APPLIED ECONOMETRICS, Issue 3 2010Fali Huang We investigate whether TV watching at ages 6,7 and 8,9 affects cognitive development measured by math and reading scores at ages 8,9, using a rich childhood longitudinal sample from NLSY79. Dynamic panel data models are estimated to handle the unobserved child-specific factor, endogeneity of TV watching, and dynamic nature of the causal relation. A special emphasis is placed on the last aspect, where TV watching affects cognitive development, which in turn affects future TV watching. When this feedback occurs, it is not straightforward to identify and estimate the TV effect. We develop a two-stage estimation method which can deal with the feedback feature; we also apply the ,standard' econometric panel data approaches. Overall, for math score at ages 8,9, we find that watching TV during ages 6,7 and 8,9 has a negative total effect, mostly due to a large negative effect of TV watching at the younger ages 6,7. For reading score, there is evidence that watching no more than 2 hours of TV per day has a positive effect, whereas the effect is negative outside this range. In both cases, however, the effect magnitudes are economically small. Copyright © 2010 John Wiley & Sons, Ltd. [source] The influence of top management team attention patterns on global strategic posture of firmsJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 7 2005Orly Levy Drawing upon the managerial cognition and the upper echelons perspectives, this study proposes that the cognitive capabilities of top executives significantly affect globalization efforts. Specifically, the study suggests that managerial attention patterns or the cognitive processes of [noticing and constructing meaning] about the environment influence strategic posture of firms. Based on a longitudinal sample of U.S. firms operating in technologically intensive industries, the results indicate that firms were more likely to develop an expansive global strategic posture when their top management paid attention to the external environment and considered a diverse set of elements in this environment. On the other hand, firms led by top management that paid more attention to the internal environment were less likely to be global. Copyright © 2005 John Wiley & Sons, Ltd. [source] "I Speak a Different Dialect": Teen Explanatory Models of Difference and DisabilityMEDICAL ANTHROPOLOGY QUARTERLY, Issue 1 2003Tamara C. Daley What do teens with disabilities believe about their conditions, and what do they understand to be the causes, correlates, and consequences of disability? We elicited a cultural explanatory model (EM) of disability from longitudinal sample of 23 European American adolescents with varied cognitive disabilities and delay. We asked teens how they were similar to different from others; the name of this difference; its causes, severity, course, effects, associated problems and benefits; and need for treatment. IQ and type of disability strongly affected quality of responses only from the lowest functioning teens. A majority of teens had a reasonably rich and coherent EM, blending typical and disability themes of cultural knowledge and identity. The EM is a window into social context (schools, services, parents, and peers) as well as personal experience. Eliciting explanatory models from teens with disabilities is not only possible but also can enhance understanding of identity, family influence, and appropriate services, [disability; explanatory models; adolescence; culture] [source] UNEMPLOYMENT DURATION, BENEFIT DURATION AND THE BUSINESS CYCLETHE ECONOMIC JOURNAL, Issue 479 2002Olympia Bover In this paper we study the effects of unemployment benefit duration and the business cycle on unemployment duration. We construct durations for individuals entering unemployment from a longitudinal sample of Spanish men in 1987,94. Estimated discrete hazard models indicate that receipt of unemployment benefits significantly reduces the hazard of leaving unemployment. At durations of three months, when the largest effects occur, the hazard for workers without benefits is twice as large as that for workers with benefits. Favourable business conditions increase the hazard of leaving unemployment. At sample-period magnitudes, this effect is significantly smaller than that of benefit receipt. [source] The Status Model of Racial Identity Development in African American Adolescents: Evidence of Structure, Trajectories, and Well-BeingCHILD DEVELOPMENT, Issue 5 2006Eleanor K. Seaton Although the identity formation model is widely used to assess adolescent ethnic identity development, the model propositions have rarely been tested. The existence of the identity statuses (diffuse, foreclosed, moratorium, achieved), the proposed developmental trajectories, and whether youth in the achieved status report higher levels of psychological well-being were examined among a longitudinal sample of 224 African American adolescents, aged 11,17. Cluster analyses were used to create 4 identity statuses consistent with the theoretical model at both time points. The findings indicate that some adolescents progressed, while others regressed or remained constant across time periods. Lastly, the results generally support the assumption that individuals in the achieved status had the highest levels of psychological well-being at both time periods. [source] Development of Self-Recognition, Personal Pronoun Use, and Pretend Play During the 2nd YearCHILD DEVELOPMENT, Issue 6 2004Michael Lewis This study examined the relation of visual self-recognition to personal pronoun use and pretend play. For a longitudinal sample (N=66) at the ages when self-recognition was emerging (15, 18, and 21 months), self-recognition was related to personal pronoun use and pretend play such that children showing self-recognition used more personal pronouns and demonstrated more advanced pretend play than did children not showing self-recognition. The finding of a relation among these measures provides additional evidence that in the middle of the 2nd year of life a metarepresentation of self emerges in the human child. [source] Gene,environment interactions and alcohol use and dependence: current status and future challengesADDICTION, Issue 6 2009Carmen S. Van Der Zwaluw ABSTRACT Aim To discuss the current status of gene,environment interaction research with regard to alcohol use and dependence. Further, we highlight the difficulties concerning gene,environment studies. Methods Overview of the current evidence for gene,environment interactions in alcohol outcomes, and of the associated challenges in gene,environment studies. Results Attention to the causative roles of gene,environment interactions in alcohol use and dependence is increasing. Studies with twin designs are beginning to examine gene-shared environment effects, and animal studies have investigated gene,environment interaction effects on alcohol intake in primates. Thirteen studies incorporated gene,environment interactions in examining alcohol use or dependence in humans. These studies held a variety of candidate genes and environmental risk factors and their heterogeneity made it impossible to draw firm general conclusions. Conclusions Challenges for future gene,environment studies are abundant, and consist of, for example, the development of clear theoretical assumptions about neurobiological mechanisms and the recruitment of large longitudinal samples that already start in childhood. Replication is essential to prevent an overload of false-positive results. Despite the difficulties, it is crucial to include gene,environment interactions in future studies in order to unravel the aetiological factors of human alcohol outcomes. [source] The Association Between Partner Enhancement and Self-Enhancement and Relationship Quality OutcomesJOURNAL OF MARRIAGE AND FAMILY, Issue 3 2009Dean M. Busby The purpose of this research was to understand in greater detail, using 2 samples (Study 1 N = 4,881 heterosexual couples; Study 2 N = 335 heterosexual couples who completed the Relationship Evaluation Questionnaire), how partner or self-enhancement patterns differentially influence relationship outcomes. A multivariate analysis of covariance was conducted comparing 4 outcome measures for different couple types in which individuals rated the partner higher, the same, or lower than they rated themselves on affability. Couples in which both individuals perceived themselves as more affable than the partner experienced poorer results on the relationship outcome measures, whereas couples in which both individuals perceived the partner's personality as more affable than their own experienced more positive relationship outcomes. Additional analyses with structural equation models demonstrated the consistent influence of enhancement measures on relationship outcomes for cross-sectional and longitudinal samples. [source] | ||||||||||||||||