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The growth in the application of information technology to student and employee learning underscores the 1 need to understand the impact of technology-mediated learning (TML) methods. Using previous developed TML [...]

INTRODUCTION It is well known that malnutrition is common among patients with head and neck (HN) cancer, both during active treatment as well as for a long period after treatment. [...], BACKGROUND/OBJECTIVES: Malnutrition decreases the cancer patient's ability to manage treatment, affects quality of life and survival, and is common among head and neck (HN) cancer patients due to the tumour location and the treatment received. In this study, advanced HN cancer patients were included and followed during 2 years in order to measure their energy intake, choice of energy sources and to assess problems with dysphagia. The main purpose was to explore when and for how long the patients had dysphagia and lost weight due to insufficient intake and if having a PEG (percutaneous endoscopic gastrostomy) in place for enteral nutrition made a difference. SUBJECTS/METHODS: One hundred thirty-four patients were included and randomised to either a prophylactic PEG for early enteral feeding or nutritional care according to clinical praxis. At seven time points weight, dysphagia and energy intake (assessed as oral, nutritional supplements, enteral and parenteral) were measured. RESULTS: Both groups lost weight the first six months due to insufficient energy intake and used enteral nutrition as their main intake source; no significant differences between groups were found. Problems with dysphagia were vast during the 6 months. At the 6-, 12- and 24-month follow-ups both groups reached estimated energy requirements and weight loss ceased. Oral intake was the major energy source after 1 year. CONCLUSIONS: HN cancer patients need nutritional support and enteral feeding for a long time period during and after treatment due to insufficient energy intake. A prophylactic PEG did not significantly improve the enteral intake probably due to treatment side effects. European Journal of Clinical Nutrition (2013) 67, 47-52;doi: 10.1038/ejcn.2012.172;published online 21 November 2012 Keywords: head and neck cancer; energy intake; nutrition sources; enteral nutrition; weight loss; dysphagia

INTRODUCTION Prevention of dementia, and particularly of Alzheimer's disease (AD), is a major challenge for researchers and clinicians. As treatment options for dementia still are very limited, knowledge of whether [...], BACKGROUND/OBJECTIVES: It is unknown if a specific fatty-acid composition influences the development of Alzheimer's disease (AD). Nutrition is a possible target for prevention of dementia and especially omega-3-based fatty acids (n-3 FAs) have previously been suggested to be beneficial for cognition. The objective was to ascertain whether serum FAs predicts the risk of incident AD and dementia in a longitudinal population-based cohort. SUBJECTS/METHODS: Uppsala Longitudinal Study of Adult Men started in 1970. The proportions of FAs in serum cholesteryl esters were estimated in men (n = 2009) who were 50 years old at baseline. During a 35 year follow-up time, 213 men had developed dementia, out of which 91 AD. The associations were analyzed with Cox proportional hazards and logistic regression; adjusted for age, education and vascular risk factors. RESULTS: Subjects with a higher proportion of saturated FAs had a decreased risk of AD in crude and multi-adjusted models (hazard ratio for 1-s.d. increase in palmitic acid 0.72;95% confidence intervals: 0.59-0.89). These associations persisted even in the group of approximately 85-year-old survivors. n-3 FAs FAs were not associated with decreased risk of AD or dementia. CONCLUSIONS: In contrast to experimental studies, saturated FAs were inversely associated with risk of AD. No evidence of a protective effect of n-3 FAs against dementia was found. The results remained essentially unchanged if competing risk from mortality was taken into account. European Journal of Clinical Nutrition (2012) 66, 885-890; doi:10.1038/ejcn.2012.63; published online 20 June 2012 Keywords: fatty acid; dementia; Alzheimer's disease

A study of the differences in psychiatric symptoms between a group of parent bereaved youths, group of youths who experienced death of another relative and a group of nonbereaved youths is presented. The findings show that both bereaved groups have more potential to show symptoms of depression and separation anxiety during the wave of death than the nonbereaved groups.

Byline: Jonathan Zaff (1), Michelle Boyd (2), Yibing Li (2), Jacqueline V. Lerner (3), Richard M. Lerner (2) Keywords: Civic engagement; Confirmatory factor analysis (CFA); Measurement invariance; Multi-group CFA; Longitudinal research; Adolescence Abstract: Civic participation does not necessarily equate to civic engagement. However, to date, integrated measures of civic engagement that go beyond civic behaviors have not been developed. In this article, we propose an integrated construct of civic engagement, active and engaged citizenship (AEC), that includes behavioral, cognitive, and socioemotional constructs. Using data from 909 adolescents (62.4% girls) who took part in the Grades 8--10 assessments of the longitudinal 4-H Study of Positive Youth Development (PYD), we assessed the structure and measurement invariance of AEC. AEC was proposed as a second-order latent construct that encompasses four first-order latent factors: Civic Duty, Civic Skills, Neighborhood Social Connection, and Civic Participation. Measurement invariance was tested over time (from Grade 8 to Grade 10) and between boys and girls. The results supported strong invariance of AEC over time and between sexes. Implications of AEC for future research and practice are discussed. Author Affiliation: (1) America's Promise Alliance, 1110 Vermont Avenue, NW, Suite 900, Washington, DC, 20005, USA (2) Tufts University, Medford, USA (3) Boston College, Boston, USA Article History: Registration Date: 16/04/2010 Received Date: 21/12/2009 Accepted Date: 16/04/2010 Online Date: 15/05/2010

The present study was aimed at examining one relatively neglected part of the identity formation process: the short-term dynamics of identity formation. The short-term dynamics were assessed by examining (a) the day-to-day course of 2 key dimensions of identity formation (i.e., commitment and reconsideration) and (b) the impact of fluctuations in commitment and reconsideration on subsequent levels of these 2 dimensions. Longitudinal data on 580 early adolescents (54.8% boys, 45.2% girls) were used to test these assertions. The authors found evidence for a commitment-reconsideration dynamic that operated on a day-to-day basis. Furthermore, the findings confirmed E. H. Erikson's (1950) assertion that identity reflects a sense of sameness and continuity as a more stable identity (reflected by little day-to-day fluctuations) was predictive of higher levels of commitment and lower levels of reconsideration. Taken together, the present study underscores the importance of the short-term dynamics of identity formation. Keywords: identity formation, commitment, short-term dynamics, fluctuations, longitudinal DOI: 10.1037/a0019584

In this 2-year longitudinal study, we hypothesized that sex of the human child (Homo sapiens), differences in physical activity, and time of the year would interact to influence preschool children's sex segregation. We also hypothesized that activity would differentially relate to peer rejection for boys and girls. Consistent with the first hypothesis, high-activity girls started off as the most integrated group bur became more segregated with time, whereas high-activity boys remained the most segregated group across the duration of the study. The second hypothesis was also supported: For girls only, activity was significantly related to peer rejection during Year 1 only, the time when high-activity girls also interacted frequently with boys. Results are discussed in terms of sexual selection theory and gender boundary violations. Keywords: sexual segregation, physical activity, sex roles, sexual dimorphism DOI: 10.1037/a0018083

Longitudinal structural equation modeling was used to evaluate longitudinal relationships across adjacent grade levels 1 to 7 for levels of language in writing (Model 1, subword letter writing, word spelling, and text composing) or writing and reading (Model 2, subword letter writing and word spelling and reading; Model 3, word spelling and reading and text composing and comprehending). Significant longitudinal relationships were observed within and across levels of language: spelling to spelling and spelling to composing (Grades 1 to 7), Models 1 and 3, and composing to spelling (Grades 3 to 6, Model 1; Grades 4 to 6, Model 3); spelling to word reading and word reading to spelling (Grades 2 to 7), Models 2 and 3; spelling to word reading (Grade 1), Model 2, and word reading to spelling (Grade 1), Model 3: composition to comprehension (Grades 3 to 5), Model 3; comprehension to composition (Grades 2 to 6), Model 3; and comprehension to word reading (Grades 1 to 6), Model 3. Results are discussed in reference to the levels of language in translating ideas into written language and integrating writing and reading. Keywords: longitudinal structural equation modeling, writing development, writing--reading relationships, spelling, composing DOI: 10.1037/a0019318

Many areas of psychological, social, and health research are characterised by hierarchically structured data. Growth curves are usually represented by means of a two-level hierarchical structure in which observations are the first-level units nested within subjects, the second-level units. With data such as these, the best option for analysis is the general linear mixed model, which can be used even with longitudinal data series in which intervals are not constant or for which over the passage of time there is loss of data. In this paper an overview is given of the general linear mixed model approach to the analysis of longitudinal data in developmental research. The advantages of this model in comparison with the traditional approaches for analysing longitudinal data are shown, emphasising the usefulness of modelling the covariance structure properly to achieve a precise estimation of the parameters of the model. DOI 10.2466/PMS.110.2.547-566

WIDESPREAD USE OF METHAMPHETAM1NE and cocaine has become a recent phenomenon in many rural areas of the United States, with some rural states overwhelmed dealing with the legal consequences and [...], Objective: Substance use is associated with poor mental health, but little is known regarding how use of multiple substances is associated with mental health, particularly longitudinally, in community studies. This article examines this issue in a large (N = 710), natural-history study of rural stimulant (cocaine and/or methamphetamine) users in three states. Method: Respondent-driven sampling recruited recent (past-30-day) stimulant users in three counties each in Arkansas, Kentucky, and Ohio. Participants were interviewed every 6 months for 3 years. Mental health was measured by the Brief Symptom Inventory, and prior 6 months' substance use was measured for 17 possible substances. Data analysis used generalized estimating equations for longitudinal data with the Global Severity Index of the Brief Symptom Inventory as the dependent variable at each interview and substance use as predictor variables measured by number of substances used in the past 6 months and, separately, the 17 individual substances, adjusting for use of substance-use treatment, demographics, and recruitment site. Results: On average, both Global Severity Index score and use of many substances declined over the course of study. Global Severity Index score was significantly associated with (a) greater number of substances used in the past 6 months (p < .0001) and (b) use of crack cocaine, methamphetamine, and nonprescription use of prescription painkillers and tranquilizers. Conclusions: Multiple and specific substances appear to incrementally increase psychological distress. Users of cocaine and methamphetamine are present in rural areas; these associations with poor psychological health raise concerns regarding availability of local treatment services for individuals with mental-health problems, as well as substance abuse. (J. Stud. Alcohol Drugs, 71, 258-267, 2010)

Our purpose in this article is to describe the objectives, design, overall coverage, and main domains of data collection of the Institute of Nutrition of Central America and Panama Oriente Longitudinal Study and subsequent follow-up studies. This supplementary feeding trial targeted to pregnant and lactating women and children from birth to 7 y of age, conducted in 4 rural Guatemalan villages (1969-77) with a series of follow-up studies (1988-2007), is one of the richest sources of information on the effects of nutrition, growth, development, and human capital in the developing world, with outstanding data from gestation to adult age and 40 y of follow-up. Its results have influenced nutrition knowledge and policy with over 300 scientific publications. We present brief descriptions of preliminary studies that were critical for the success of the trial and the design and methods used during the trial and in the follow-up studies, in chronological order. J. Nutr. 140: 397-401, 2010. doi: 10.3945/jn.109.114470.

Heterogeneity often exists among behavioral growth trajectories in a study population. In the evaluation of intervention effects for longitudinal randomized trials, it is informative to examine the impact of an intervention on subgroups characterized by different types of growth trajectories. This paper presents an application of growth mixture modeling to an ordinal-scale substance-use behavior outcome from the Aban Aya Youth Project (AAYP), a longitudinal preventive intervention trial targeting health-compromising behaviors among adolescents. Results suggested two classes of adolescent substance use growth trajectories: Class 1 (44.7% of the sample) started at a higher level and had a relatively shallow increase over time; Class 2 had a lower baseline level and a rapid increase over time. The intervention effectively reduced the rapid increase of substance use for the adolescents in the second class.

The group-based latent trajectory model allows investigators to identify distinctive trajectory groups based on relevant outcomes. Dual trajectory analysis enables examination of the interrelationship between two outcomes simultaneously. This paper describes the application of the group-based dual trajectory model in mental health and substance abuse research. We analyzed two related recovery outcomes: 1) social contact with non-substance abusing friends and 2) stage of substance abuse treatment. We identified four groups for social contact and four groups for substance abuse treatment. We then examined the interrelationship between the two outcomes across the trajectory groups over 10 years. The two outcomes are positively associated longitudinally and evolve in the same direction, although for specific groups, the two outcomes do not covary. By examining dynamic linkages across all trajectory groups between two longitudinal outcomes, the dual model provides a more comprehensive and realistic understanding of the underlying relationships between the two outcomes under investigation.

The growth curve modeling (GCM) technique has been widely adopted in longitudinal studies to investigate progression over time. The simplest growth profile involves two growth factors, initial status (intercept) and growth trajectory (slope). Conventionally, all repeated measures of outcome are included as components of the growth profile, and the first measure is used to reflect the initial status. Selection of the initial status, however, can greatly influence study findings, especially for randomized trials. In this article, we propose an alternative GCM approach involving only post-intervention measures in the growth profile and treating the first wave after intervention as the initial status. We discuss and empirically illustrate how choices of initial status may influence study conclusions in addressing research questions in randomized trials using two longitudinal studies. Data from two randomized trials are used to illustrate that the alternative GCM approach proposed in this article offers better model fitting and more meaningful results.

The importance of spatial ability in educational pursuits and the world of work was examined, with particular attention devoted to STEM (science, technology, engineering, and mathematics) domains. Participants were drawn from a stratified random sample of U.S. high schools (Grades 9-12, N = 400,000) and were tracked for 11 + years; their longitudinal findings were aligned with pre-1957 findings and with contemporary data from the Graduate Record Examination and the Study of Mathematically Precocious Youth. For decades, spatial ability assessed during adolescence has surfaced as a salient psychological attribute among those adolescents who subsequently go on to achieve advanced educational credentials and occupations in STEM. Results solidify the generalization that spatial ability plays a critical role in developing expertise in STEM and suggest, among other things, that including spatial ability in modern talent searches would identify many adolescents with potential for STEM who are currently being missed. Keywords: spatial ability, talent searches, longitudinal study, STEM, constructive replication DOI: 10.1037/a0016127

Both cross-sectional and longitudinal research depict a decline in the fruit and vegetable consumption (FVC) of children and youths with age, but identifying developmental changes and their influences with regard to FVC cannot be fully explained with application of only one of these research designs. Reviewed here are results from longitudinal and cross-sectional research, and a proposal is presented for a lifespan development methodology that uses a sequential design strategy to illuminate the multilevel processes that determine FVC. Conclusions from the review were similar for both cross-sectional and longitudinal research, with fruit and vegetable (FV) preferences and FV accessibility/availability being the most consistent influences on FVC Furthermore, this review illuminates several methodological issues, offering suggestions to strengthen comparisons between studies. Research designs that incorporate longitudinal, cross-sectional, and time-lag data are warranted.

Studying human development involves describing, explaining, and optimizing intraindividual change and interindividual differences in such change and, as such, requires longitudinal research. The selection of the appropriate type of longitudinal design requires selecting the option that best addresses the theoretical questions asked about developmental process and the use of appropriate statistical procedures to best exploit data derived from theory-predicated longitudinal research. This paper focuses on several interrelated problematics involving the treatment of time and the timing of observations that developmental scientists face in creating theory-design fit and in charting in change-sensitive ways developmental processes across life. We discuss ways in which these problematics may be addressed to advance theory-predicated understanding of the role of time in processes of individual development. Key Words Individual development * Intraindividual change * Longitudinal research * Time and timing of observations

This article reviews the premises of configural frequency analysis (CFA), including methods of choosing significance tests and base models, as well as protecting [alpha], and discusses why CFA is a useful approach when conducting longitudinal person-oriented research. CFA operates at the manifest variable level. Longitudinal CFA seeks to identify those temporal patterns that stand out as more frequent (CFA types) or less frequent (CFA antitypes) than expected with reference to a base model. A base model that has been used frequently in CFA applications, prediction CFA, and a new base model, auto--association CFA, are discussed for analysis of cross-classifications of longitudinal data. The former base model takes the associations among predictors and among criteria into account. The latter takes the auto-associations among repeatedly observed variables into account. Application examples of each are given using data from a longitudinal study of domestic violence. It is demonstrated that CFA results are not redundant with results from log-linear modeling or multinomial regression and that, of these approaches, CFA shows particular utility when conducting person-oriented research. Keywords: configural frequency analysis, longitudinal models, prediction configural frequency analysis, auto-association configural frequency analysis, person-oriented research Supplemental materials: http://dx.doi.org/10.1037/0012-1649.44.2.437.supp

This study estimates the prevalence of productive engagement among adults aged 60 and over residing in the United States over a nine-year period. We analyze three waves of data from the Americans' Changing Lives Study, which allows the findings to describe the non-institutionalized older American population. Focusing upon five activities--formal paid employment, irregular paid work, unpaid volunteerism, caregiving, and informal assistance to others--we identify changes in the engagement rates, examine the extent to which engagement occurs through single or multiple concurrent activities, and document intra-individual patterns of engagement within and across forms of productive activity, including the continuity, initiation, and cessation of involvement. The findings reveal that late-life productive engagement is widespread, with the majority of older individuals involved in multiple forms of activity concurrently. Non--market-based activities such as caregiving, informal assistance, and volunteering are most prevalent. Initiation and cessation of activities are common and yield more complex patterns and lower rates of non-participation than are revealed in cross-sectional analyses. Time spent in productive engagement is highly variable and exhibits an overall decline across time. We conclude by highlighting policy strategies to increase the availability and quality of opportunities for productive engagement and promote planning for engagement in late life. KEYWORDS. Productive engagement, longitudinal analyses, employment, caregiving, voluntarism, civic engagement, public policy

We analyze measurement and classification errors in several key variables in a matched sample of survey and administrative longitudinal data on employees spanning 1994-2001. The data are much more comprehensive than usually seen in validation studies. Measurement errors in earnings are found to be much larger than reported in previous studies limited to one single firm. A key finding is that employees who attrite from the panel report their earnings significantly less accurate than individuals who are observed throughout the entire sampling period. Keywords: Measurement error, classification error, validation

Research shows that Dutch smokers with lower education level engage in smoking, suggesting that the general perception of health and age of smoking initiation are indicators of educational differences and ccontinuation of smoking by a population of 1,354 smoking adults.

Results do not support a relationship between changes in smoking and changes in drinking. The structural equation model incorporating data from 344 adults suggests that changes in the drinking behavior are not related to changes in smoking behavior.

Analysis of individual growth curves is a useful technique in analyzing longitudinal data in marital research. This method assesses individual change over time, or growth curves, using multiple waves of data. Approaches currently in use generate incomplete and potentially inaccurate descriptions of how marriages change since they use only two waves of data at a time. A step-by-step guide to the technique is presented.

Many clinical studies require the longitudinal collection of data over time. As data collection may not be uniformly collected on each patient (e.g., blood tests may be performed regularly in some patients and sporadically in others), it is important to understand the frequency and patterns of data collection events over time so that statistical analyses can be planned. We demonstrate the use of a graphical technique, the FU-PLOT (short for Follow-Up PLOT), that can assist research investigators and statisticians in visualizing the frequency and patterns of follow-up data collection. Examples are from a longitudinal study of children born to mothers infected with the human immunodeficiency virus (HIV). The method can be adapted to a variety of situations, and is easily programmed in most graphics, spreadsheet, and statistical packages. KEY WORDS: Clinical trials; Follow-up; Graphics; Longitudinal studies., 1. INTRODUCTION The longitudinal follow-up of patients is a feature of many clinical studies. To facilitate data collection and eventual statistical analysis, the investigator may try to collect follow-up data [...]

Cohort studies typically require repeated contacts with the same study participants over many years. In large-scale follow-up studies of women, it can be difficult to locate and maintain contact with participants because women are more likely to experience name changes through marriage and divorce and may be less visible in public records, particularly contemporary elderly women. This article reports on the methods used in 1990 and 1991 to trace 998 participants of the Women's Health Study (WHS) who were enrolled during the 1930s in the Menstruation and Reproductive History study, a longitudinal study on menstruation and reproduction. Some of these women had been lost to follow-up for nearly 50 years. This article reviews the strategies used to locate the WHS participants.

A multimode field design was used to assess reasons for participant refusal as well as to study the effect of specific field procedures to minimize drop-out by refusal. This includes theuse of proxy respondents to study the reasons for participant refusal in a random sample of elderly individuals. Subjects who initially refused were functionally independent and cited disinterest as reason for refusal. About 43%of those who initially refused and only 27% of those with proxy respondents were convinced to continue participation usually by a phone call. Results also show that the very old and disabled may be included in longitudinal studies.

The paper examines some of the technical and epistemological questions raised by the debate on linking qualitative and quantitative research methodologies. (1) For illustrative purposes, we discuss a qualitative research project on the distribution of resources within households currently being conducted by the British Household Panel Study at the University of Essex. Initially, we provide a general background to the current research, moving on to examine some of the methodological problems which emerge and the epistemological questions which they raise. These include the general issue of classification; the difficulties of defining the analytical boundaries of households; the particular problems associated with using households as longitudinal units of analysis; and the relationship between actors' accounts and the conceptual categories which we use to describe behaviour. We suggest that the tendency to see qualitative and quantitative methodologies as mutually exclusive and antagonistic paradigms is a misleading representation of the reality of social research practice, and argue for the importance of maintaining a qualitative component in the BHPS in order to understand the complex processes involved in the intra-household distribution of resources.

Longitudinal studies of aboriginal children over a 20-year period have drawn attention to the wide variation in morphological features of the dentition and the way in which occlusal relationships develop. This paper summarizes some important determinants of optimal occlusal development, namely, tooth size relationships within and between dentitions, the patterns of alveolar growth, and tooth migrations during the transition from primary to permanent teeth and the nature of growth changes in the dental arches. Dental occlusion constantly changes throughout life in response to changing functional requirements. Observations limited to cross-sectional material provide an incomplete, and sometimes misleading, concept of dental occlusion and masticatory function.

Abstract. This study, set in the context of a longitudinal interpretative case study of the literacy learning of one child, Sarah, from age 2-5, documents the role and significance Sarah's [...]