Regression Models for the Analysis of Longitudinal Gaussian Data from Multiple Sources

PubMed Central

O’Brien, Liam M.; Fitzmaurice, Garrett M.

2006-01-01

We present a regression model for the joint analysis of longitudinal multiple source Gaussian data. Longitudinal multiple source data arise when repeated measurements are taken from two or more sources, and each source provides a measure of the same underlying variable and on the same scale. This type of data generally produces a relatively large number of observations per subject; thus estimation of an unstructured covariance matrix often may not be possible. We consider two methods by which parsimonious models for the covariance can be obtained for longitudinal multiple source data. The methods are illustrated with an example of multiple informant data arising from a longitudinal interventional trial in psychiatry. PMID:15726666

Student Leadership Development: A Functional Framework

ERIC Educational Resources Information Center

Hine, Gregory Stephen Colin

2014-01-01

This article presents a longitudinal, qualitative case study of a student leadership program in a Catholic secondary school in Perth, Western Australia. Data were collected over a period of three years through multiple methods, including one-on-one interviewing, focus group interviewing, document searches, field notes, and researcher reflective…

L2 Learners' Informal Online Interactions in Social Network Communities

ERIC Educational Resources Information Center

Malerba, Maria-Luisa

2012-01-01

This paper reports on a study on the use of social network sites (SNSs) designed for L2 learning, such as "Livemocha" and "Busuu", where learners autonomously seek opportunities for authentic interaction in spontaneous ways. The study consists in a longitudinal multiple case study approach to investigate learners' informal…

Are We Preparing or Training Teachers? Developing Professional Judgment in and beyond Teacher Preparation Programs

ERIC Educational Resources Information Center

Scales, Roya Q.; Wolsey, Thomas DeVere; Lenski, Susan; Smetana, Linda; Yoder, Karen K.; Dobler, Elizabeth; Grisham, Dana L.; Young, Janet R.

2018-01-01

This three phase longitudinal multiple-case study, framed by positioning theory, investigated how four novice teachers learned to use professional judgment in their literacy instruction. Data sources from coursework, student teaching, and novice teaching were included. Interviews, observations, researchers' observational notes, and school and…

Intercultural Identity and Intercultural Experiences of American Students in China

ERIC Educational Resources Information Center

Tian, Mei; Lowe, John Anthony

2014-01-01

The number of international students in China is increasing rapidly, but their experiences in China remain largely unknown. This article reports an intensive longitudinal multiple case study that explores eight American students' intercultural experiences and the impacts of such experiences on individual identity during their study in a Chinese…

Deadlines at work and sleep quality. Cross-sectional and longitudinal findings among Danish knowledge workers.

PubMed

Rugulies, Reiner; Martin, Marie H T; Garde, Anne Helene; Persson, Roger; Albertsen, Karen

2012-03-01

Exposure to deadlines at work is increasing in several countries and may affect health. We aimed to investigate cross-sectional and longitudinal associations between frequency of difficult deadlines at work and sleep quality. Study participants were knowledge workers, drawn from a representative sample of Danish employees who responded to a baseline questionnaire in 2006 (n = 363) and a follow-up questionnaire in 2007 (n = 302). Frequency of difficult deadlines was measured by self-report and categorized into low, intermediate, and high. Sleep quality was measured with a Total Sleep Quality Score and two indexes (Awakening Index and Disturbed Sleep Index) derived from the Karolinska Sleep Questionnaire. Analyses on the association between frequency of deadlines and sleep quality scores were conducted with multiple linear regression models, adjusted for potential confounders. In addition, we used multiple logistic regression models to analyze whether frequency of deadlines at baseline predicted caseness of sleep problems at follow-up among participants free of sleep problems at baseline. Frequent deadlines were cross-sectionally and longitudinally associated with poorer sleep quality on all three sleep quality measures. Associations in the longitudinal analyses were greatly attenuated when we adjusted for baseline sleep quality. The logistic regression analyses showed that frequent deadlines at baseline were associated with elevated odds ratios for caseness of sleep problems at follow-up, however, confidence intervals were wide in these analyses. Frequent deadlines at work were associated with poorer sleep quality among Danish knowledge workers. We recommend investigating the relation between deadlines and health endpoints in large-scale epidemiologic studies. Copyright © 2011 Wiley Periodicals, Inc.

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nong, Hanond, E-mail: Nong.Hanond@rub.de; Markmann, Sergej; Hekmat, Negar

2014-09-15

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunesmore » the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.« less

Sustaining Online Teacher Professional Development through Community Design

ERIC Educational Resources Information Center

Henderson, Michael

2007-01-01

Purpose: The purpose of this paper is to explore the role of community of practice in sustaining teachers' participation in a blended (face-to-face and online) professional development course. Design/methodology/approach: A longitudinal multiple-case study methodology was used in researching groups of five teachers in Australia and four teachers…

A Longitudinal Perspective of Early Career Music Teachers: Contexts, Interactions, and Possible Selves

ERIC Educational Resources Information Center

Dabback, William

2018-01-01

The purpose of this multiple case study was to follow the development of three music educators during their student teaching semesters and into the first years of their careers. Possible selves theory provided a framework for exploring the links between cognition, expectations, and motivation. Interviewees negotiated their social and physical…

A Hot-Deck Multiple Imputation Procedure for Gaps in Longitudinal Recurrent Event Histories

PubMed Central

Wang, Chia-Ning; Little, Roderick; Nan, Bin; Harlow, Siobán D.

2012-01-01

Summary We propose a regression-based hot deck multiple imputation method for gaps of missing data in longitudinal studies, where subjects experience a recurrent event process and a terminal event. Examples are repeated asthma episodes and death, or menstrual periods and the menopause, as in our motivating application. Research interest concerns the onset time of a marker event, defined by the recurrent-event process, or the duration from this marker event to the final event. Gaps in the recorded event history make it difficult to determine the onset time of the marker event, and hence, the duration from onset to the final event. Simple approaches such as jumping gap times or dropping cases with gaps have obvious limitations. We propose a procedure for imputing information in the gaps by substituting information in the gap from a matched individual with a completely recorded history in the corresponding interval. Predictive Mean Matching is used to incorporate information on longitudinal characteristics of the repeated process and the final event time. Multiple imputation is used to propagate imputation uncertainty. The procedure is applied to an important data set for assessing the timing and duration of the menopausal transition. The performance of the proposed method is assessed by a simulation study. PMID:21361886

A case of seropositive Neuromyelitis Optica in a paediatric patient with co-existing acute nephrotic syndrome.

PubMed

Volkman, Thomas; Hemingway, Cheryl

2017-11-01

Neuromyelitis optica (NMO) and NMO spectrum disorder (NMOSD) is a rare relapsing autoimmune disease of the central nervous system constituting less than 1% of demyelinating diseases (Jeffery and Buncic, 1996). It preferentially affects the optic nerves and spinal cord, with the brain parenchyma generally spared. Demyelinating lesions are characterised by longitudinally extensive transverse myelitis (LETM) and often longitudinally extensive optic neuritis. Following the discovery of a novel pathogenic antibody, Aquaporin 4 in 2004 (Lennon et al., 2004) this disease has been seen as a separate entity from Multiple Sclerosis (MS). We report the case of a severe AQP4 IgG case of NMO in a 10 year old child. This case unusually had a coexisting diagnosis of acute nephrotic syndrome which has only been reported once previously in the literature 2 . This article will examine some of the treatment challenges and the spectrum of co-existing autoimmune disease in NMOSD. Copyright © 2017. Published by Elsevier B.V.

Significant geographic gradients in particulate sulfate over Japan determined from multiple-site measurements and a chemical transport model: Impacts of transboundary pollution from the Asian continent

NASA Astrophysics Data System (ADS)

Aikawa, Masahide; Ohara, Toshimasa; Hiraki, Takatoshi; Oishi, Okihiro; Tsuji, Akihiro; Yamagami, Makiko; Murano, Kentaro; Mukai, Hitoshi

2010-01-01

We found a significant geographic gradient (longitudinal and latitudinal) in the sulfate (SO 42-) concentrations measured at multiple sites over the East Asian Pacific Rim region. Furthermore, the observed gradient was well reproduced by a regional chemical transport model. The observed and modeled SO 42- concentrations were higher at the sites closer to the Asian continent. The concentrations of SO 42- from China as calculated by the model also showed the fundamental features of the longitudinal/latitudinal gradient. The proportional contribution of Chinese SO 42- to the total in Japan throughout the year was above 50-70% in the control case, using data for Chinese sulfur dioxide (SO 2) emission from the Regional Emission Inventory in Asia (40-60% in the low Chinese emissions case, using Chinese SO 2 emissions data from the State Environmental Protection Administration of China), with a winter maximum of approximately 65-80%, although the actual concentrations of SO 42- from China were highest in summer. The multiple-site measurements and the model analysis strongly suggest that the SO 42- concentrations in Japan were influenced by the outflow from the Asian continent, and this influence was greatest in the areas closer to the Asian continent. In contrast, we found no longitudinal/latitudinal gradient in SO 2 concentrations; instead SO 2 concentrations were significantly correlated with local SO 2 emissions. Our results show that large amounts of particulate sulfate are transported over long distances from the East Asian Pacific Rim region, and consequently the SO 42- concentrations in Japan are controlled by the transboundary outflow from the Asian continent.

Occurrence of Multiple Sclerosis After Drug Exposure: Insights From Evidence Mapping.

PubMed

Antonazzo, Ippazio Cosimo; Raschi, Emanuel; Vignatelli, Luca; Baldin, Elisa; Riise, Trond; D'Alessandro, Roberto; De Ponti, Fabrizio; Poluzzi, Elisabetta

2017-09-01

The role of drugs in the occurrence of multiple sclerosis (MS) is perceived to be insufficiently investigated. The aim of this study was to map and assess the evidence on MS occurrence after drug exposure, in order to identify possible signals of causal association. A search strategy was performed in MEDLINE and Embase as of July 2016; references consistent with the aim of the study were analysed to extract relevant measures of causal association between drugs and MS. The Newcastle-Ottawa Scale and appropriate guidelines from the International Society for Pharmacoepidemiology (ISPE) and the International Society of Pharmacovigilance (ISoP) were used to assess the quality of included studies. After screening 832 articles, 58 were selected (of which 14 were found by checking the reference lists of reviews): 30 case reports and case series, 24 longitudinal studies and four randomized controlled trials. Seven longitudinal studies had good (at least 7 out of 9) quality scores, whereas case reports/case series presented several limitations. Half of included articles focused on immunomodulatory drugs (etanercept, infliximab and adalimumab), especially in case reports/series, suggesting an association with MS occurrence. Contraceptives and antibacterials were investigated in some population-based studies, without definite results. A heterogeneous pharmacological profile of identified classes emerged. Low strength of evidence and conflicting results highlighted the difficulties in addressing the possible contribution of drugs in MS occurrence. Methodological advances are needed, especially to control the confounding role of underlying disease for specific drug classes.

"It's Different Lives": A Guatemalan American Adolescent's Construction of Ethnic and Gender Identities across Educational Contexts

ERIC Educational Resources Information Center

Ek, Lucila D.

2009-01-01

Drawing from a multiyear ethnography and a longitudinal case study, this article examines how one Guatemalan American teenager negotiates the multiple socializations to ethnic and gender identities in her home, her Pentecostal church, and her high school. She must face processes of Americanization and Mexicanization. Americanization's thrust is to…

Exploring Long-Term Productive Vocabulary Development in an EFL Context: The Role of Motivation

ERIC Educational Resources Information Center

Zheng, Yongyan

2012-01-01

The paper reports on a longitudinal multiple-case study that probed into four advanced university-level Chinese EFL learners' situated vocabulary learning experiences and explored the role of L2 motivation in their productive vocabulary development. In the study, Lexical Frequency Profile analysis and semi-structured interviews were conducted with…

The Role of Multiple-Group Measurement Invariance in Family Psychology Research

ERIC Educational Resources Information Center

Kern, Justin L.; McBride, Brent A.; Laxman, Daniel J.; Dyer, W. Justin; Santos, Rosa M.; Jeans, Laurie M.

2016-01-01

Measurement invariance (MI) is a property of measurement that is often implicitly assumed, but in many cases, not tested. When the assumption of MI is tested, it generally involves determining if the measurement holds longitudinally or cross-culturally. A growing literature shows that other groupings can, and should, be considered as well.…

Art Making as a Mental Health Recovery Tool for Change and Coping

ERIC Educational Resources Information Center

Van Lith, Theresa

2015-01-01

The intrinsic benefits of art making may be implicated in how and why people with mental illness turn to art therapy to aid their recovery. In this longitudinal multiple case study adult participants (N = 12) with severe and ongoing mental illness were recruited through their involvement in diverse community mental health art therapy programs. An…

Residual Strength Pressure Tests and Nonlinear Analyses of Stringer- and Frame-Stiffened Aluminum Fuselage Panels with Longitudinal Cracks

NASA Technical Reports Server (NTRS)

Young, Richard D.; Rouse, Marshall; Ambur, Damodar R.; Starnes, James H., Jr.

1999-01-01

The results of residual strength pressure tests and nonlinear analyses of stringer- and frame-stiffened aluminum fuselage panels with longitudinal cracks are presented. Two types of damage are considered: a longitudinal crack located midway between stringers, and a longitudinal crack adjacent to a stringer and along a row of fasteners in a lap joint that has multiple-site damage (MSD). In both cases, the longitudinal crack is centered on a severed frame. The panels are subjected to internal pressure plus axial tension loads. The axial tension loads are equivalent to a bulkhead pressure load. Nonlinear elastic-plastic residual strength analyses of the fuselage panels are conducted using a finite element program and the crack-tip-opening-angle (CTOA) fracture criterion. Predicted crack growth and residual strength results from nonlinear analyses of the stiffened fuselage panels are compared with experimental measurements and observations. Both the test and analysis results indicate that the presence of MSD affects crack growth stability and reduces the residual strength of stiffened fuselage shells with long cracks.

Residual Strength Pressure Tests and Nonlinear Analyses of Stringer-and Frame-Stiffened Aluminum Fuselage Panels with Longitudinal Cracks

NASA Technical Reports Server (NTRS)

Young, Richard D.; Rouse, Marshall; Ambur, Damodar R.; Starnes, James H., Jr.

1998-01-01

The results of residual strength pressure tests and nonlinear analyses of stringer- and frame-stiffened aluminum fuselage panels with longitudinal cracks are presented. Two types of damage are considered: a longitudinal crack located midway between stringers, and a longitudinal crack adjacent to a stringer and along a row of fasteners in a lap joint that has multiple-site damage (MSD). In both cases, the longitudinal crack is centered on a severed frame. The panels are subjected to internal pressure plus axial tension loads. The axial tension loads are equivalent to a bulkhead pressure load. Nonlinear elastic-plastic residual strength analyses of the fuselage panels are conducted using a finite element program and the crack-tip-opening-angle (CTOA) fracture criterion. Predicted crack growth and residual strength results from nonlinear analyses of the stiffened fuselage panels are compared with experimental measurements and observations. Both the test and analysis results indicate that the presence of MSD affects crack growth stability and reduces the residual strength of stiffened fuselage shells with long cracks.

Identifying reprioritization response shift in a stroke caregiver population: a comparison of missing data methods.

PubMed

Sajobi, Tolulope T; Lix, Lisa M; Singh, Gurbakhshash; Lowerison, Mark; Engbers, Jordan; Mayo, Nancy E

2015-03-01

Response shift (RS) is an important phenomenon that influences the assessment of longitudinal changes in health-related quality of life (HRQOL) studies. Given that RS effects are often small, missing data due to attrition or item non-response can contribute to failure to detect RS effects. Since missing data are often encountered in longitudinal HRQOL data, effective strategies to deal with missing data are important to consider. This study aims to compare different imputation methods on the detection of reprioritization RS in the HRQOL of caregivers of stroke survivors. Data were from a Canadian multi-center longitudinal study of caregivers of stroke survivors over a one-year period. The Stroke Impact Scale physical function score at baseline, with a cutoff of 75, was used to measure patient stroke severity for the reprioritization RS analysis. Mean imputation, likelihood-based expectation-maximization imputation, and multiple imputation methods were compared in test procedures based on changes in relative importance weights to detect RS in SF-36 domains over a 6-month period. Monte Carlo simulation methods were used to compare the statistical powers of relative importance test procedures for detecting RS in incomplete longitudinal data under different missing data mechanisms and imputation methods. Of the 409 caregivers, 15.9 and 31.3 % of them had missing data at baseline and 6 months, respectively. There were no statistically significant changes in relative importance weights on any of the domains when complete-case analysis was adopted. But statistical significant changes were detected on physical functioning and/or vitality domains when mean imputation or EM imputation was adopted. There were also statistically significant changes in relative importance weights for physical functioning, mental health, and vitality domains when multiple imputation method was adopted. Our simulations revealed that relative importance test procedures were least powerful under complete-case analysis method and most powerful when a mean imputation or multiple imputation method was adopted for missing data, regardless of the missing data mechanism and proportion of missing data. Test procedures based on relative importance measures are sensitive to the type and amount of missing data and imputation method. Relative importance test procedures based on mean imputation and multiple imputation are recommended for detecting RS in incomplete data.

A Critical Account of Employability Construction through the Eyes of Chinese Postgraduate Students in the UK

ERIC Educational Resources Information Center

Li, Zhen

2013-01-01

This paper presents a multiple ("n"?=?23), longitudinal case study of the construction of personal employability by Chinese students at a UK university. It draws on the work of Brown and Hesketh to frame notions of employability in order to understand how these students engage with the international and Chinese labour markets from their…

The Fluctuating Development of Cross-Linguistic Semantic Awareness: A Longitudinal Multiple-Case Study

ERIC Educational Resources Information Center

Zheng, Yongyan

2014-01-01

Second language (L2) learners' awareness of first language-second language (L1-L2) semantic differences plays a critical role in L2 vocabulary learning. This study investigates the long-term development of eight university-level Chinese English as a foreign language learners' cross-linguistic semantic awareness over the course of 10 months. A…

Measurement bias detection with Kronecker product restricted models for multivariate longitudinal data: an illustration with health-related quality of life data from thirteen measurement occasions

PubMed Central

Verdam, Mathilde G. E.; Oort, Frans J.

2014-01-01

Highlights Application of Kronecker product to construct parsimonious structural equation models for multivariate longitudinal data. A method for the investigation of measurement bias with Kronecker product restricted models. Application of these methods to health-related quality of life data from bone metastasis patients, collected at 13 consecutive measurement occasions. The use of curves to facilitate substantive interpretation of apparent measurement bias. Assessment of change in common factor means, after accounting for apparent measurement bias. Longitudinal measurement invariance is usually investigated with a longitudinal factor model (LFM). However, with multiple measurement occasions, the number of parameters to be estimated increases with a multiple of the number of measurement occasions. To guard against too low ratios of numbers of subjects and numbers of parameters, we can use Kronecker product restrictions to model the multivariate longitudinal structure of the data. These restrictions can be imposed on all parameter matrices, including measurement invariance restrictions on factor loadings and intercepts. The resulting models are parsimonious and have attractive interpretation, but require different methods for the investigation of measurement bias. Specifically, additional parameter matrices are introduced to accommodate possible violations of measurement invariance. These additional matrices consist of measurement bias parameters that are either fixed at zero or free to be estimated. In cases of measurement bias, it is also possible to model the bias over time, e.g., with linear or non-linear curves. Measurement bias detection with Kronecker product restricted models will be illustrated with multivariate longitudinal data from 682 bone metastasis patients whose health-related quality of life (HRQL) was measured at 13 consecutive weeks. PMID:25295016

Measurement bias detection with Kronecker product restricted models for multivariate longitudinal data: an illustration with health-related quality of life data from thirteen measurement occasions.

PubMed

Verdam, Mathilde G E; Oort, Frans J

2014-01-01

Application of Kronecker product to construct parsimonious structural equation models for multivariate longitudinal data.A method for the investigation of measurement bias with Kronecker product restricted models.Application of these methods to health-related quality of life data from bone metastasis patients, collected at 13 consecutive measurement occasions.The use of curves to facilitate substantive interpretation of apparent measurement bias.Assessment of change in common factor means, after accounting for apparent measurement bias.Longitudinal measurement invariance is usually investigated with a longitudinal factor model (LFM). However, with multiple measurement occasions, the number of parameters to be estimated increases with a multiple of the number of measurement occasions. To guard against too low ratios of numbers of subjects and numbers of parameters, we can use Kronecker product restrictions to model the multivariate longitudinal structure of the data. These restrictions can be imposed on all parameter matrices, including measurement invariance restrictions on factor loadings and intercepts. The resulting models are parsimonious and have attractive interpretation, but require different methods for the investigation of measurement bias. Specifically, additional parameter matrices are introduced to accommodate possible violations of measurement invariance. These additional matrices consist of measurement bias parameters that are either fixed at zero or free to be estimated. In cases of measurement bias, it is also possible to model the bias over time, e.g., with linear or non-linear curves. Measurement bias detection with Kronecker product restricted models will be illustrated with multivariate longitudinal data from 682 bone metastasis patients whose health-related quality of life (HRQL) was measured at 13 consecutive weeks.

Multivariate longitudinal data analysis with censored and intermittent missing responses.

PubMed

Lin, Tsung-I; Lachos, Victor H; Wang, Wan-Lun

2018-05-08

The multivariate linear mixed model (MLMM) has emerged as an important analytical tool for longitudinal data with multiple outcomes. However, the analysis of multivariate longitudinal data could be complicated by the presence of censored measurements because of a detection limit of the assay in combination with unavoidable missing values arising when subjects miss some of their scheduled visits intermittently. This paper presents a generalization of the MLMM approach, called the MLMM-CM, for a joint analysis of the multivariate longitudinal data with censored and intermittent missing responses. A computationally feasible expectation maximization-based procedure is developed to carry out maximum likelihood estimation within the MLMM-CM framework. Moreover, the asymptotic standard errors of fixed effects are explicitly obtained via the information-based method. We illustrate our methodology by using simulated data and a case study from an AIDS clinical trial. Experimental results reveal that the proposed method is able to provide more satisfactory performance as compared with the traditional MLMM approach. Copyright © 2018 John Wiley & Sons, Ltd.

Human longevity and variation in GH/IGF-1/insulin signaling, DNA damage signaling and repair and pro/antioxidant pathway genes: cross sectional and longitudinal studies.

PubMed

Soerensen, Mette; Dato, Serena; Tan, Qihua; Thinggaard, Mikael; Kleindorp, Rabea; Beekman, Marian; Jacobsen, Rune; Suchiman, H Eka D; de Craen, Anton J M; Westendorp, Rudi G J; Schreiber, Stefan; Stevnsner, Tinna; Bohr, Vilhelm A; Slagboom, P Eline; Nebel, Almut; Vaupel, James W; Christensen, Kaare; McGue, Matt; Christiansen, Lene

2012-05-01

Here we explore association with human longevity of common genetic variation in three major candidate pathways: GH/IGF-1/insulin signaling, DNA damage signaling and repair and pro/antioxidants by investigating 1273 tagging SNPs in 148 genes composing these pathways. In a case-control study of 1089 oldest-old (age 92-93) and 736 middle-aged Danes we found 1 pro/antioxidant SNP (rs1002149 (GSR)), 5 GH/IGF-1/INS SNPs (rs1207362 (KL), rs2267723 (GHRHR), rs3842755 (INS), rs572169 (GHSR), rs9456497 (IGF2R)) and 5 DNA repair SNPs (rs11571461 (RAD52), rs13251813 (WRN), rs1805329 (RAD23B), rs2953983 (POLB), rs3211994 (NTLH1)) to be associated with longevity after correction for multiple testing. In a longitudinal study with 11 years of follow-up on survival in the oldest-old Danes we found 2 pro/antioxidant SNPs (rs10047589 (TNXRD1), rs207444 (XDH)), 1 GH/IGF-1/INS SNP (rs26802 (GHRL)) and 3 DNA repair SNPs (rs13320360 (MLH1), rs2509049 (H2AFX) and rs705649 (XRCC5)) to be associated with mortality in late life after correction for multiple testing. When examining the 11 SNPs from the case-control study in the longitudinal data, rs3842755 (INS), rs13251813 (WRN) and rs3211994 (NTHL1) demonstrated the same directions of effect (p<0.05), while rs9456497 (IGF2R) and rs1157146 (RAD52) showed non-significant tendencies, indicative of effects also in late life survival. In addition, rs207444 (XDH) presented the same direction of effect when inspecting the 6 SNPs from the longitudinal study in the case-control data, hence, suggesting an effect also in survival from middle age to old age. No formal replications were observed when investigating the 11 SNPs from the case-control study in 1613 oldest-old (age 95-110) and 1104 middle-aged Germans, although rs11571461 (RAD52) did show a supportive non-significant tendency (OR=1.162, 95% CI=0.927-1.457). The same was true for rs10047589 (TNXRD1) (HR=0.758, 95%CI=0.543-1.058) when examining the 6 SNPs from the longitudinal study in a Dutch longitudinal cohort of oldest-old (age 85+, N=563). In conclusion, the present candidate gene based association study, the largest to date applying a pathway approach, not only points to potential new longevity loci, but also underlines the difficulties of replicating association findings in independent study populations and thus the difficulties in identifying universal longevity polymorphisms. Copyright © 2012 Elsevier Inc. All rights reserved.

Joint models for longitudinal and time-to-event data: a review of reporting quality with a view to meta-analysis.

PubMed

Sudell, Maria; Kolamunnage-Dona, Ruwanthi; Tudur-Smith, Catrin

2016-12-05

Joint models for longitudinal and time-to-event data are commonly used to simultaneously analyse correlated data in single study cases. Synthesis of evidence from multiple studies using meta-analysis is a natural next step but its feasibility depends heavily on the standard of reporting of joint models in the medical literature. During this review we aim to assess the current standard of reporting of joint models applied in the literature, and to determine whether current reporting standards would allow or hinder future aggregate data meta-analyses of model results. We undertook a literature review of non-methodological studies that involved joint modelling of longitudinal and time-to-event medical data. Study characteristics were extracted and an assessment of whether separate meta-analyses for longitudinal, time-to-event and association parameters were possible was made. The 65 studies identified used a wide range of joint modelling methods in a selection of software. Identified studies concerned a variety of disease areas. The majority of studies reported adequate information to conduct a meta-analysis (67.7% for longitudinal parameter aggregate data meta-analysis, 69.2% for time-to-event parameter aggregate data meta-analysis, 76.9% for association parameter aggregate data meta-analysis). In some cases model structure was difficult to ascertain from the published reports. Whilst extraction of sufficient information to permit meta-analyses was possible in a majority of cases, the standard of reporting of joint models should be maintained and improved. Recommendations for future practice include clear statement of model structure, of values of estimated parameters, of software used and of statistical methods applied.

A study of the temporal stability of multiple cell vortices

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R.

1989-01-01

The effect of initial mean velocity field on the stability characteristics of longitudinal vortices is documented in detail. The temporal stability of isolated multiple cell vortices is considered. The types of vortices studied include single cell as well as two and three cell vortices. It is shown that cell multiplicity in the vortex core has drastic effects on the stability characteristics. On the basis of numerical calculations, it is concluded that the growth rates of instabilities in multiple cell vortices are substantially larger (two to threefold increases are observed) than those of a single cell vortex. It is also determined that there is a substantial increase in the effective range of axial and azimuthal wavenumbers where instabilities are present. But most importantly, there is the appearance of a variety of viscous modes of instability. In the case of vortices, these latter instabilities which highlight the importance of viscous forces have never been reported before. These effects are discussed in detail for the case of a two cell vortex.

Identification of treatment responders based on multiple longitudinal outcomes with applications to multiple sclerosis patients.

PubMed

Kondo, Yumi; Zhao, Yinshan; Petkau, John

2017-05-30

Identification of treatment responders is a challenge in comparative studies where treatment efficacy is measured by multiple longitudinally collected continuous and count outcomes. Existing procedures often identify responders on the basis of only a single outcome. We propose a novel multiple longitudinal outcome mixture model that assumes that, conditionally on a cluster label, each longitudinal outcome is from a generalized linear mixed effect model. We utilize a Monte Carlo expectation-maximization algorithm to obtain the maximum likelihood estimates of our high-dimensional model and classify patients according to their estimated posterior probability of being a responder. We demonstrate the flexibility of our novel procedure on two multiple sclerosis clinical trial datasets with distinct data structures. Our simulation study shows that incorporating multiple outcomes improves the responder identification performance; this can occur even if some of the outcomes are ineffective. Our general procedure facilitates the identification of responders who are comprehensively defined by multiple outcomes from various distributions. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Family Implementation of Positive Behavior Support for a Child with Autism: Longitudinal, Single-Case, Experimental, and Descriptive Replication and Extension

ERIC Educational Resources Information Center

Lucyshyn, Joseph M.; Albin, Richard W.; Horner, Robert H.; Mann, Jane C.; Mann, James A.; Wadsworth, Gina

2007-01-01

This study examined the efficacy, social validity, and durability of a positive behavior support (PBS) approach with the family of a girl with autism and severe problem behavior. The study was conducted across a 10-year period beginning when the child was 5 years old. A multiple baseline across family routines design evaluated the functional…

Predicting Disease Progression in Scleroderma with Skin and Blood Biomarkers

DTIC Science & Technology

2016-12-01

epidermal differentiation in addition to those involved in extracel- lular matrix production and myofibroblast contractility (35). In a followup study ...important manifestation of SSc are needed. Several studies have linked autoantibody production with genetics in SSc. Multiple polymorphisms in the human...longitudinal clinical data and genetic markers. GENISOS is an inception cohort that avoids survival bias inherent in studies of prevalent cases (mean disease

A structured framework for assessing sensitivity to missing data assumptions in longitudinal clinical trials.

PubMed

Mallinckrodt, C H; Lin, Q; Molenberghs, M

2013-01-01

The objective of this research was to demonstrate a framework for drawing inference from sensitivity analyses of incomplete longitudinal clinical trial data via a re-analysis of data from a confirmatory clinical trial in depression. A likelihood-based approach that assumed missing at random (MAR) was the primary analysis. Robustness to departure from MAR was assessed by comparing the primary result to those from a series of analyses that employed varying missing not at random (MNAR) assumptions (selection models, pattern mixture models and shared parameter models) and to MAR methods that used inclusive models. The key sensitivity analysis used multiple imputation assuming that after dropout the trajectory of drug-treated patients was that of placebo treated patients with a similar outcome history (placebo multiple imputation). This result was used as the worst reasonable case to define the lower limit of plausible values for the treatment contrast. The endpoint contrast from the primary analysis was - 2.79 (p = .013). In placebo multiple imputation, the result was - 2.17. Results from the other sensitivity analyses ranged from - 2.21 to - 3.87 and were symmetrically distributed around the primary result. Hence, no clear evidence of bias from missing not at random data was found. In the worst reasonable case scenario, the treatment effect was 80% of the magnitude of the primary result. Therefore, it was concluded that a treatment effect existed. The structured sensitivity framework of using a worst reasonable case result based on a controlled imputation approach with transparent and debatable assumptions supplemented a series of plausible alternative models under varying assumptions was useful in this specific situation and holds promise as a generally useful framework. Copyright © 2012 John Wiley & Sons, Ltd.

Multiple imputation as one tool to provide longitudinal databases for modelling human height and weight development.

PubMed

Aßmann, C

2016-06-01

Besides large efforts regarding field work, provision of valid databases requires statistical and informational infrastructure to enable long-term access to longitudinal data sets on height, weight and related issues. To foster use of longitudinal data sets within the scientific community, provision of valid databases has to address data-protection regulations. It is, therefore, of major importance to hinder identifiability of individuals from publicly available databases. To reach this goal, one possible strategy is to provide a synthetic database to the public allowing for pretesting strategies for data analysis. The synthetic databases can be established using multiple imputation tools. Given the approval of the strategy, verification is based on the original data. Multiple imputation by chained equations is illustrated to facilitate provision of synthetic databases as it allows for capturing a wide range of statistical interdependencies. Also missing values, typically occurring within longitudinal databases for reasons of item non-response, can be addressed via multiple imputation when providing databases. The provision of synthetic databases using multiple imputation techniques is one possible strategy to ensure data protection, increase visibility of longitudinal databases and enhance the analytical potential.

Orthodontic exposure of multiple lmpactions: a case report.

PubMed

Munda-Lacson, Maridin C; Venugopal, Adith

2014-01-01

There are rare cases of impacted permanent central incisors with dilacerations, a dental deformity characterized by pronounced angulations of the longitudinal tooth axis. Impaction of maxillary canines is an orthodontic anomaly that causes facial and dentoalveolar system problems, both functional and esthetic. A combination of surgery and orthodontics is important in bringing impacted teeth to their ideal position in the dental arch. This is a case report of a 10-year-old patient with impacted and dilacerated right central incisor and impacted left maxillary canine, following surgical exposure and appropriate orthodontic traction, the impacted teeth were surgically exposed and aligned into the dental arch.

Patterns and correlates of co-occurrence among multiple types of child maltreatment

PubMed Central

Kim, Kihyun; Mennen, Ferol E.; Trickett, Penelope K.

2017-01-01

This study examined the patterns and correlates of the types of maltreatment experienced by adolescents aged 9–12, participating in an ongoing longitudinal study on the impact of neglect on children’s development. Using case record abstraction, the study compared the child protection classification and findings from the case record abstraction with regard to the rates of four types of maltreatment (i.e. physical, sexual, emotional abuse and neglect) as well as co-occurrence across multiple types of maltreatment. Next, the study examined the frequently observed patterns of child maltreatment. Finally, the study investigated whether aspects of caretaker functioning and the detailed incident characteristics in the cases of neglect differed by the number of different types of maltreatment the children experienced. Results showed significant discrepancies between the Child Protective Service classification and case record abstraction. Child Protective Service classification considerably underestimated the rate of co-occurrence across multiple types of maltreatment. Neglect accompanied by physical and emotional abuse was the most common form. Some of the caretaker functioning variables distinguished the number of types of maltreatment. Based on the findings, future-research directions and practice implication were discussed. PMID:29225485

"But Before I Go to My Next Step": A Longitudinal Study of Adolescent English Language Learners' Transitional Devices in Oral Presentations

ERIC Educational Resources Information Center

Kibler, Amanda K.; Salerno, April S.; Palacios, Natalia

2014-01-01

This multiple case study examines patterns in the oral second language use of three Spanish-speaking English language learners in rehearsed presentations produced annually over 4 years (Grades 9-12) in a U.S. high school. Analysis focuses on students' changing use of transitional devices called frame markers (Hyland, 2005) as a lens for…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samet, J.; Gilliland, F.D.

This project incorporates two related research projects directed toward understanding respiratory carcinogenesis in radon-exposed former uranium miners. The first project involved a continuation of the tissue resource of lung cancer cases from former underground uranium miners and comparison cases from non-miners. The second project was a pilot study for a proposed longitudinal study of respiratory carcinogenesis in former uranium miners. The objectives including facilitating the investigation of molecular changes in radon exposed lung cancer cases, developing methods for prospectively studying clinical, cytologic, cytogenetic, and molecular changes in the multi-event process of respiratory carcinogenesis, and assessing the feasibility of recruiting formermore » uranium miners into a longitudinal study that collected multiple biological specimens. A pilot study was conducted to determine whether blood collection, induced sputum, bronchial brushing, washings, and mucosal biopsies from participants at two of the hospitals could be included efficiently. A questionnaire was developed for the extended study and all protocols for specimen collection and tissue handling were completed. Resource utilization is in progress at ITRI and the methods have been developed to study molecular and cellular changes in exfoliated cells contained in sputum as well as susceptibility factors.« less

Cytomegalovirus Colitis in a Critically Ill Patient Following Severe Legionella Pneumonia with Multiple Organ Failure.

PubMed

Nakashima, Kei; Aoshima, Masahiro; Suzuki, Fumi; Watanabe, Junko; Otsuka, Yoshihito

2016-01-01

A 68-year-old man visited an emergency department complaining of dyspnea. He was diagnosed to have Legionella pneumonia with multiple organ failure. Although his multiple organ failure improved, he suffered from persistent abdominal pain and diarrhea with continuous minor bleeding. Colonoscopy revealed a longitudinal ulcer of the rectum, below the peritoneal reflection. He was diagnosed with cytomegalovirus (CMV) colitis. Antiviral therapy with ganciclovir was initiated. He finally underwent a colostomy after a bowel stricture caused an intestinal outlet obstruction, which made oral intake impossible. Based on the present case, we believe that CMV colitis must be considered as one of the differential diagnoses when critically ill patients develop continuous diarrhea and abdominal pain.

Multiple Kernel Learning with Random Effects for Predicting Longitudinal Outcomes and Data Integration

PubMed Central

Chen, Tianle; Zeng, Donglin

2015-01-01

Summary Predicting disease risk and progression is one of the main goals in many clinical research studies. Cohort studies on the natural history and etiology of chronic diseases span years and data are collected at multiple visits. Although kernel-based statistical learning methods are proven to be powerful for a wide range of disease prediction problems, these methods are only well studied for independent data but not for longitudinal data. It is thus important to develop time-sensitive prediction rules that make use of the longitudinal nature of the data. In this paper, we develop a novel statistical learning method for longitudinal data by introducing subject-specific short-term and long-term latent effects through a designed kernel to account for within-subject correlation of longitudinal measurements. Since the presence of multiple sources of data is increasingly common, we embed our method in a multiple kernel learning framework and propose a regularized multiple kernel statistical learning with random effects to construct effective nonparametric prediction rules. Our method allows easy integration of various heterogeneous data sources and takes advantage of correlation among longitudinal measures to increase prediction power. We use different kernels for each data source taking advantage of the distinctive feature of each data modality, and then optimally combine data across modalities. We apply the developed methods to two large epidemiological studies, one on Huntington's disease and the other on Alzheimer's Disease (Alzheimer's Disease Neuroimaging Initiative, ADNI) where we explore a unique opportunity to combine imaging and genetic data to study prediction of mild cognitive impairment, and show a substantial gain in performance while accounting for the longitudinal aspect of the data. PMID:26177419

DEMONSTRATION OF LOW COST, LOW BURDEN EXPOSURE MONITORING STRATEGIES FOR USE IN LONGITUDINAL COHORT STUDIES

EPA Science Inventory

A large longitudinal cohort study designed to evaluate the association between children's exposures to environmental agents and health outcomes presents many challenges for exposure monitoring. Exposure of the child must be measured for multiple chemicals through multiple path...

Spinal Cord Herniation After Cervical Corpectomy with Cerebrospinal Fluid Leak: Case Report and Review of the Literature.

PubMed

Guppy, Kern H; Silverthorn, James W

2017-04-01

Spinal cord herniation (SCH) is rare, is mostly idiopathic, and occurs predominantly in the thoracic spine. SCH is less common in the cervical spine and has been reported after posterior cervical spine surgery associated with the development of pseudomeningoceles. Two cases of SCH have been reported after anterior cervical corpectomies for ossified posterior longitudinal ligament with cerebrospinal fluid (CSF) leaks. We report the third such case, but the first in a patient without ossified posterior longitudinal ligament (degenerative disc disease and pseudarthrosis). A 56-year-old woman presented with bilateral arm pain and weakness. She had undergone 3 previous anterior cervical spine surgeries at an outside medical center with the most recent 7 years ago with C5 and C6 corpectomies and fusion with a persistent CSF leak. Magnetic resonance imaging and computed tomography myelography showed spinal cord herniation through the mesh cage at C6. The patient underwent a redo C5 and C6 corpectomy with untethering of the spinal cord. The patient was asymptomatic 2 years later. This is the first reported case of anterior cervical SCH in a patient without ossified posterior longitudinal ligament after multiple anterior cervical fusions including a cervical corpectomy for pseudarthrosis with a CSF leak. We hypothesize that persistent CSF leak causes a pressure gradient across the dura mater through the cage to the lower pressure in the retropharyngeal space, which led to herniation of the spinal cord into the anterior cage. We review the literature and discuss the treatment choices for anterior cervical SCH. Copyright © 2017 Elsevier Inc. All rights reserved.

The evaluation of complex interventions in palliative care: an exploration of the potential of case study research strategies.

PubMed

Walshe, Catherine

2011-12-01

Complex, incrementally changing, context dependent and variable palliative care services are difficult to evaluate. Case study research strategies may have potential to contribute to evaluating such complex interventions, and to develop this field of evaluation research. This paper explores definitions of case study (as a unit of study, a process, and a product) and examines the features of case study research strategies which are thought to confer benefits for the evaluation of complex interventions in palliative care settings. Ten features of case study that are thought to be beneficial in evaluating complex interventions in palliative care are discussed, drawing from exemplars of research in this field. Important features are related to a longitudinal approach, triangulation, purposive instance selection, comprehensive approach, multiple data sources, flexibility, concurrent data collection and analysis, search for proving-disproving evidence, pattern matching techniques and an engaging narrative. The limitations of case study approaches are discussed including the potential for subjectivity and their complex, time consuming and potentially expensive nature. Case study research strategies have great potential in evaluating complex interventions in palliative care settings. Three key features need to be exploited to develop this field: case selection, longitudinal designs, and the use of rival hypotheses. In particular, case study should be used in situations where there is interplay and interdependency between the intervention and its context, such that it is difficult to define or find relevant comparisons.

Leveraging electronic health records to support chronic disease management: the need for temporal data views.

PubMed

Samal, Lipika; Wright, Adam; Wong, Bang T; Linder, Jeffrey A; Bates, David W

2011-01-01

The ageing population worldwide is increasingly acquiring multiple chronic diseases. The complex management of chronic diseases could be improved with electronic health records (EHRs) tailored to chronic disease care, but most EHRs in use today do not adequately support longitudinal data management. A key aspect of chronic disease management is that it takes place over long periods, but the way that most EHRs display longitudinal data makes it difficult to trend changes over time and slows providers as they review each patient's unique course. We present five clinical scenarios illustrating longitudinal data needs in complex chronic disease management. These scenarios may function as example cases for software development. For each scenario, we describe and illustrate improvements in temporal data views. Two potential solutions are visualisation for numerical data and disease-oriented text summaries for non-numerical data. We believe that development and widespread implementation of improved temporal data views in EHRs will improve the efficiency and quality of chronic disease management in primary care.

Using multi-ring structure for suppression of mode competition in stable single-longitudinal-mode erbium fiber laser

NASA Astrophysics Data System (ADS)

Yeh, Chien-Hung; Huang, Tzu-Jung; Yang, Zi-Qing; Chow, Chi-Wai

2017-12-01

In this demonstration, a stable and tunable single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser with multiple-ring configuration is proposed and investigated. The proposed compound-ring structure can create different free spectrum ranges (FSRs) to result in the mode-filter effect based on the Vernier effect for suppressing the other modes. Additionally, the output stabilization of power and wavelength in the proposed EDF multiple-ring laser are also discussed.

Cognitive Performance in Older Adults with Stable Heart Failure: Longitudinal Evidence for Stability and Improvement

PubMed Central

Alosco, Michael L.; Garcia, Sarah; Spitznagel, Mary Beth; van Dulmen, Manfred; Cohen, Ronald; Sweet, Lawrence H.; Josephson, Richard; Hughes, Joel; Rosneck, Jim; Gunstad, John

2013-01-01

Cognitive impairment is prevalent in heart failure (HF), though substantial variability in the pattern of cognitive impairment is found across studies. To clarify the nature of cognitive impairment in HF, we examined longitudinal trajectories across multiple domains of cognition in HF patients using latent growth class modeling. 115 HF patients completed a neuropsychological battery at baseline, 3-months and 12-months. Participants also completed the Beck Depression Inventory-II (BDI-II). Latent class growth analyses revealed a three-class model for attention/executive function, four-class model for memory, and a three-class model for language. The slope for attention/executive function and language remained stable, while improvements were noted in memory performance. Education and BDI-II significantly predicted the intercept for attention/executive function and language abilities. The BDI-II also predicted baseline memory. The current findings suggest that multiple performance-based classes of neuropsychological test performance exist within cognitive domains, though case-controlled prospective studies with extended follow-ups are needed to fully elucidate changes and predictors of cognitive function in HF. PMID:23906182

Patterns of Doctoral Student Degree Completion: A Longitudinal Analysis

ERIC Educational Resources Information Center

Most, David E.

2008-01-01

Despite decades of interest in Ph.D. student outcomes, there have been few comprehensive studies of doctoral student completion. Compared to research on undergraduate students, longitudinal studies of doctoral student completion in multiple disciplines at multiple institutions are exceptionally rare. As a consequence, there is relatively scant…

Vibration Measurement on Reticular Lamina and Basilar Membrane at Multiple Longitudinal Locations

NASA Astrophysics Data System (ADS)

Chen, Fangyi; Zha, Dingjun; Choudhury, Niloy; Fridberger, Anders; Nuttall, Alfred L.

2011-11-01

The longitudinal distribution of the organ of Corti vibration is important for both understanding the energy delivery and the timing of the cochlear amplification. Recent development on low coherence interferomtry technique allows measuring vibration inside the cochlea. The reticular lamina (RL) vibration spectrum demonstrates that RL vibration leads the basilar membrane (BM). This phase lead is consistent with the idea that the active process may lead the BM vibration. In this study, measurements on multiple longitudinal locations demonstrated similar phase lead. Results on this study suggests that there may be another longitudinal coupling mechanism inside the cochlea other than the traveling wave on BM.

Longitudinal Analysis of the Premature Infant Intestinal Microbiome Prior to Necrotizing Enterocolitis: A Case-Control Study

PubMed Central

Zhou, Yanjiao; Shan, Gururaj; Sodergren, Erica; Weinstock, George; Walker, W. Allan; Gregory, Katherine E.

2015-01-01

Necrotizing enterocolitis (NEC) is an inflammatory disease of the newborn bowel, primarily affecting premature infants. Early intestinal colonization has been implicated in the pathogenesis of NEC. The objective of this prospective case-control study was to evaluate differences in the intestinal microbiota between infants who developed NEC and unaffected controls prior to disease onset. We conducted longitudinal analysis of the 16S rRNA genes of 312 samples obtained from 12 NEC cases and 26 age-matched controls with a median frequency of 7 samples per subject and median sampling interval of 3 days. We found that the microbiome undergoes dynamic development during the first two months of life with day of life being the major factor contributing to the colonization process. Depending on when the infant was diagnosed with NEC (i.e. early vs. late onset), the pattern of microbial progression was different for cases and controls. The difference in the microbiota was most overt in early onset NEC cases and controls. In proximity to NEC onset, the abundances of Clostridium sensu stricto from Clostridia class were significantly higher in early onset NEC subjects comparing to controls. In late onset NEC, Escherichia/Shigella among Gammaproteobacteria, showed an increasing pattern prior to disease onset, and was significantly higher in cases than controls six days before NEC onset. Cronobacter from Gammaproteobacteria was also significantly higher in late onset NEC cases than controls 1-3 days prior to NEC onset. Thus, the specific infectious agent associated with NEC may vary by the age of infant at disease onset. We found that intravenously administered antibiotics may have an impact on the microbial diversity present in fecal material. Longitudinal analysis at multiple time points was an important strategy utilized in this study, allowing us to appreciate the dynamics of the premature infant intestinal microbiome while approaching NEC at various points. PMID:25741698

Acute respiratory infection case definitions for young children: a systematic review of community-based epidemiologic studies in South Asia.

PubMed

Roth, Daniel E; Gaffey, Michelle F; Smith-Romero, Evelyn; Fitzpatrick, Tiffany; Morris, Shaun K

2015-12-01

To explore the variability in childhood acute respiratory infection case definitions for research in low-income settings where there is limited access to laboratory or radiologic investigations. We conducted a systematic review of community-based, longitudinal studies in South Asia published from January 1990 to August 2013, in which childhood acute respiratory infection outcomes were reported. Case definitions were classified by their label (e.g. pneumonia, acute lower respiratory infection) and clinical content 'signatures' (array of clinical features that would be always present, conditionally present or always absent among cases). Case definition heterogeneity was primarily assessed by the number of unique case definitions overall and by label. We also compared case definition-specific acute respiratory infection incidence rates for studies reporting incidence rates for multiple case definitions. In 56 eligible studies, we found 124 acute respiratory infection case definitions. Of 90 case definitions for which clinical content was explicitly defined, 66 (73%) were unique. There was a high degree of content heterogeneity among case definitions with the same label, and some content signatures were assigned multiple labels. Within studies for which incidence rates were reported for multiple case definitions, variation in content was always associated with a change in incidence rate, even when the content differed by a single clinical feature. There has been a wide variability in case definition label and content combinations to define acute upper and lower respiratory infections in children in community-based studies in South Asia over the past two decades. These inconsistencies have important implications for the synthesis and translation of knowledge regarding the prevention and treatment of childhood acute respiratory infection. © 2015 John Wiley & Sons Ltd.

Longitudinal Data on the Effectiveness of Mathematics Mini-Games in Primary Education

ERIC Educational Resources Information Center

Bakker, Marjoke; Van den Heuvel-Panhuizen, Marja; Robitzsch, Alexander

2015-01-01

This paper describes a dataset consisting of longitudinal data gathered in the BRXXX project. The aim of the project was to investigate the effectiveness of online mathematics mini-games in enhancing primary school students' multiplicative reasoning ability (multiplication and division). The dataset includes data of 719 students from 35 primary…

Latent Variable Regression 4-Level Hierarchical Model Using Multisite Multiple-Cohorts Longitudinal Data. CRESST Report 801

ERIC Educational Resources Information Center

Choi, Kilchan

2011-01-01

This report explores a new latent variable regression 4-level hierarchical model for monitoring school performance over time using multisite multiple-cohorts longitudinal data. This kind of data set has a 4-level hierarchical structure: time-series observation nested within students who are nested within different cohorts of students. These…

Generating qualitative data by design: the Australian Longitudinal Study on Women's Health qualitative data collection.

PubMed

Tavener, Meredith; Chojenta, Catherine; Loxton, Deborah

2016-07-15

Objectives and importance of study: The purpose of this study was to illustrate how qualitative free-text comments, collected within the context of a health survey, represent a rich data source for understanding specific phenomena. Work conducted with data from the Australian Longitudinal Study on Women's Health (ALSWH) was used to demonstrate the breadth and depth of qualitative information that can be collected. The ALSWH has been collecting data on women's health since 1996, and represents a unique opportunity for understanding lived experiences across the lifecourse. A multiple case study design was used to demonstrate the techniques that researchers have used to manage free-text qualitative comments collected by the ALSWH. Eleven projects conducted using free-text comments are discussed according to the method of analysis. These methods include coding (both inductively and deductively), longitudinal analyses and software-based analyses. This work shows that free-text comments are a data resource in their own right, and have the potential to provide rich and valuable information about a wide variety of topics.

Modeling Life-Span Growth Curves of Cognition Using Longitudinal Data with Multiple Samples and Changing Scales of Measurement

ERIC Educational Resources Information Center

McArdle, John J.; Grimm, Kevin J.; Hamagami, Fumiaki; Bowles, Ryan P.; Meredith, William

2009-01-01

The authors use multiple-sample longitudinal data from different test batteries to examine propositions about changes in constructs over the life span. The data come from 3 classic studies on intellectual abilities in which, in combination, 441 persons were repeatedly measured as many as 16 times over 70 years. They measured cognitive constructs…

Causal Latent Markov Model for the Comparison of Multiple Treatments in Observational Longitudinal Studies

ERIC Educational Resources Information Center

Bartolucci, Francesco; Pennoni, Fulvia; Vittadini, Giorgio

2016-01-01

We extend to the longitudinal setting a latent class approach that was recently introduced by Lanza, Coffman, and Xu to estimate the causal effect of a treatment. The proposed approach enables an evaluation of multiple treatment effects on subpopulations of individuals from a dynamic perspective, as it relies on a latent Markov (LM) model that is…

Multivariate longitudinal data analysis with mixed effects hidden Markov models.

PubMed

Raffa, Jesse D; Dubin, Joel A

2015-09-01

Multiple longitudinal responses are often collected as a means to capture relevant features of the true outcome of interest, which is often hidden and not directly measurable. We outline an approach which models these multivariate longitudinal responses as generated from a hidden disease process. We propose a class of models which uses a hidden Markov model with separate but correlated random effects between multiple longitudinal responses. This approach was motivated by a smoking cessation clinical trial, where a bivariate longitudinal response involving both a continuous and a binomial response was collected for each participant to monitor smoking behavior. A Bayesian method using Markov chain Monte Carlo is used. Comparison of separate univariate response models to the bivariate response models was undertaken. Our methods are demonstrated on the smoking cessation clinical trial dataset, and properties of our approach are examined through extensive simulation studies. © 2015, The International Biometric Society.

A Fast EM Algorithm for Fitting Joint Models of a Binary Response and Multiple Longitudinal Covariates Subject to Detection Limits

PubMed Central

Bernhardt, Paul W.; Zhang, Daowen; Wang, Huixia Judy

2014-01-01

Joint modeling techniques have become a popular strategy for studying the association between a response and one or more longitudinal covariates. Motivated by the GenIMS study, where it is of interest to model the event of survival using censored longitudinal biomarkers, a joint model is proposed for describing the relationship between a binary outcome and multiple longitudinal covariates subject to detection limits. A fast, approximate EM algorithm is developed that reduces the dimension of integration in the E-step of the algorithm to one, regardless of the number of random effects in the joint model. Numerical studies demonstrate that the proposed approximate EM algorithm leads to satisfactory parameter and variance estimates in situations with and without censoring on the longitudinal covariates. The approximate EM algorithm is applied to analyze the GenIMS data set. PMID:25598564

Factors affecting continuation of clean intermittent catheterisation in people with multiple sclerosis: Results of the COSMOS mixed-methods study.

PubMed

McClurg, Doreen; Bugge, Carol; Elders, Andrew; Irshad, Tasneem; Hagen, Suzanne; Moore, Katherine N; Buckley, Brian; Fader, Mandy

2018-04-01

Clean intermittent catheterisation (CIC) is often recommended for people with multiple sclerosis (MS). To determine the variables that affect continuation or discontinuation of the use of CIC. A three-part mixed-method study (prospective longitudinal cohort ( n = 56), longitudinal qualitative interviews ( n = 20) and retrospective survey ( n = 456)) was undertaken, which identified the variables that influenced CIC continuation/discontinuation. The potential explanatory variables investigated in each study were the individual's age, gender, social circumstances, number of urinary tract infections, bladder symptoms, presence of co-morbidity, stage of multiple sclerosis and years since diagnosis, as well as CIC teaching method and intensity. For some people with MS the prospect of undertaking CIC is difficult and may take a period of time to accept before beginning the process of using CIC. Ongoing support from clinicians, support at home and a perceived improvement in symptoms such as nocturia were positive predictors of continuation. In many cases, the development of a urinary tract infection during the early stages of CIC use had a significant detrimental impact on continuation. Procedures for reducing the incidence of urinary tract infection during the learning period (i.e. when being taught and becoming competent) should be considered, as well as the development of a tool to aid identification of a person's readiness to try CIC.

Comparing multiple imputation methods for systematically missing subject-level data.

PubMed

Kline, David; Andridge, Rebecca; Kaizar, Eloise

2017-06-01

When conducting research synthesis, the collection of studies that will be combined often do not measure the same set of variables, which creates missing data. When the studies to combine are longitudinal, missing data can occur on the observation-level (time-varying) or the subject-level (non-time-varying). Traditionally, the focus of missing data methods for longitudinal data has been on missing observation-level variables. In this paper, we focus on missing subject-level variables and compare two multiple imputation approaches: a joint modeling approach and a sequential conditional modeling approach. We find the joint modeling approach to be preferable to the sequential conditional approach, except when the covariance structure of the repeated outcome for each individual has homogenous variance and exchangeable correlation. Specifically, the regression coefficient estimates from an analysis incorporating imputed values based on the sequential conditional method are attenuated and less efficient than those from the joint method. Remarkably, the estimates from the sequential conditional method are often less efficient than a complete case analysis, which, in the context of research synthesis, implies that we lose efficiency by combining studies. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Refractory status epilepticus and autoimmune encephalitis with GABAAR and GAD65 antibodies: A case report.

PubMed

Gagnon, Maude-Marie; Savard, Martin; Mourabit Amari, Karim

2016-04-01

Autoimmune encephalitis is an inflammatory disorder of the brain that may be associated with different neuronal antibodies. Recently, an increasing number of valuable autoantibodies have been identified, including GABAAR antibodies, which appear to be associated with a severe form of encephalitis with refractory status epilepticus. We report here on a patient with encephalitis associated with GAD65 and GABAAR antibodies, an entity that remains an understudied topic, with an unanticipated clinical presentation and we describe the longitudinal follow-up. We report a case of encephalitis associated with GAD65 and GABAAR antibodies; we describe clinical and paraclinical features and the longitudinal follow-up. Our case presented with dysgueusia, dysosmia and episodes of hyperventilation that evolved into a refractory status epilepticus. Multiple anticonvulsant drugs were required. An aggressive immunotherapy was associated with a relative favorable outcome, in regard of epilepsy and cognitive functions. However, a relapse occurred and a full recovery was not observed at the last follow-up visit. There was no correlation between GAD65 antibodies titers and disease activity. Autoimmune encephalitis associated with GABAAR and GAD65 antibodies might be a severe and refractory disease. The appropriate treatment is currently unknown for those patients. Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Reconstruction of the Midfoot Using a Free Vascularized Fibular Graft After En Bloc Excision for Giant Cell Tumor of the Tarsal Bones: A Case Report.

PubMed

Hara, Hitomi; Kawamoto, Teruya; Onishi, Yasuo; Fujioka, Hiroyuki; Nishida, Kotaro; Kuroda, Ryosuke; Kurosaka, Masahiro; Akisue, Toshihiro

2016-01-01

We report the case of a 32-year-old Japanese female with a giant cell tumor of bone involving multiple midfoot bones. Giant cell tumors of bone account for approximately 5% of all primary bone tumors and most often arise at the ends of long bones. The small bones, such as those of the hands and feet, are rare sites for giant cell tumors. Giant cell tumors of the small bones tend to exhibit more aggressive clinical behavior than those of the long bones. The present patient underwent en bloc tumor excision involving multiple tarsals and metatarsals. We reconstructed the longitudinal arch of the foot with a free vascularized fibular graft. At the 2-year follow-up visit, bony union had been achieved, with no tumor recurrence. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

POSTOP: Postbuckled open-stiffener optimum panels, user's manual

NASA Technical Reports Server (NTRS)

Biggers, S. B.; Dickson, J. N.

1984-01-01

The computer program POSTOP developed to serve as an aid in the analysis and sizing of stiffened composite panels that may be loaded in the postbuckling regime, is intended for the preliminary design of metal or composite panels with open-section stiffeners, subjected to multiple combined biaxial compression (or tension), shear and normal pressure load cases. Longitudinal compression, however, is assumed to be the dominant loading. Temperature, initial bow eccentricity and load eccentricity effects are included. The panel geometry is assumed to be repetitive over several bays in the longitudinal (stiffener) direction as well as in the transverse direction. Analytical routines are included to compute panel stiffnesses, strains, local and panel buckling loads, and skin/stiffener interface stresses. The resulting program is applicable to stiffened panels as commonly used in fuselage, wing, or empennage structures. The capabilities and limitations of the code are described. Instructions required to use the program and several example problems are included.

Impact of integrated programs on general surgery operative volume.

PubMed

Jensen, Amanda R; Nickel, Brianne L; Dolejs, Scott C; Canal, David F; Torbeck, Laura; Choi, Jennifer N

2017-03-01

Integrated residencies are now commonplace, co-existing with categorical general surgery residencies. The purpose of this study was to define the impact of integrated programs on categorical general surgery operative volume. Case logs from categorical general, integrated plastics, vascular, and thoracic surgery residents from a single institution from 2008 to 2016 were collected and analyzed. Integrated residents have increased the number of cases they perform that would have previously been general surgery resident cases from 11 in 2009-2010 to 1392 in 2015-2016. Despite this, there was no detrimental effect on total major cases of graduating chief residents. Multiple integrated programs can co-exist with a general surgery program through careful collaboration and thoughtful consideration to longitudinal needs of individual trainees. As additional programs continue to be created, both integrated and categorical program directors must continue to collaborate to insure the integrity of training for all residents. Copyright © 2017 Elsevier Inc. All rights reserved.

Reducing Bias Due to Systematic Attrition in Longitudinal Studies: The Benefits of Multiple Imputation

ERIC Educational Resources Information Center

Asendorpf, Jens B.; van de Schoot, Rens; Denissen, Jaap J. A.; Hutteman, Roos

2014-01-01

Most longitudinal studies are plagued by drop-out related to variables at earlier assessments (systematic attrition). Although systematic attrition is often analysed in longitudinal studies, surprisingly few researchers attempt to reduce biases due to systematic attrition, even though this is possible and nowadays technically easy. This is…

Polydactylous Transverse Erythronychia: Report of a Patient with Multiple Horizontal Red Bands Affecting the Fingernails.

PubMed

Chang, Carina; Beutler, Bryce D; Cohen, Philip R

2017-06-01

Redness of the nail plate-erythronychia-is a common condition involving one or multiple digits. It may affect the entire nail or present as longitudinal red bands that extend from the proximal nail fold to the distal tip of the nail plate. Rarely, red bands may traverse the nail bed horizontally. Although erythronychia is often idiopathic, it has also been associated with amyloidosis, Darier's disease, lichen planus, and various other cutaneous conditions. We describe the clinical features of a 64-year-old Caucasian man who presented with transverse and longitudinal erythronychia affecting his fingernails. In addition, we review the classification of erythronychia and summarize the acute and chronic conditions that have been associated with this clinical finding. The features of a man with polydactylous transverse and longitudinal erythronychia are presented. In addition, PubMed was used to search the following terms: erythronychia, longitudinal erythronychia, red lunulae, and subungual. All papers were reviewed, and relevant articles, along with their references, were evaluated. Informed consent was obtained from the patient for being included in the study. A 64-year-old Caucasian man with a past medical history significant for testicular cancer and pulmonary embolism presented with multiple horizontal pink-red bands affecting his fingernails. The discoloration was most prominent in the region distal to the lunula. In addition, the nails of the fifth digit of his left hand and third digit of his right hand featured longitudinal red bands extending from the distal curvature of the lunula to the free edge of the nail plate. A diagnosis of polydactylous longitudinal and transverse erythronychia, based on the clinical presentation, was established. Our patient's red bands were asymptomatic and he was not concerned about the cosmetic appearance of his nails; therefore, no additional investigation or treatment was required. Polydactylous transverse erythronychia is a rare condition characterized by the development of horizontal red bands affecting the fingernails or toe nails. It has only been previously described in a man with multiple system atrophy. In our patient, both transverse and longitudinal red bands were present simultaneously. Therefore, it is possible that horizontal erythronychia is an early clinical manifestation of longitudinal erythronychia.

Multiple Imputation based Clustering Validation (MIV) for Big Longitudinal Trial Data with Missing Values in eHealth.

PubMed

Zhang, Zhaoyang; Fang, Hua; Wang, Honggang

2016-06-01

Web-delivered trials are an important component in eHealth services. These trials, mostly behavior-based, generate big heterogeneous data that are longitudinal, high dimensional with missing values. Unsupervised learning methods have been widely applied in this area, however, validating the optimal number of clusters has been challenging. Built upon our multiple imputation (MI) based fuzzy clustering, MIfuzzy, we proposed a new multiple imputation based validation (MIV) framework and corresponding MIV algorithms for clustering big longitudinal eHealth data with missing values, more generally for fuzzy-logic based clustering methods. Specifically, we detect the optimal number of clusters by auto-searching and -synthesizing a suite of MI-based validation methods and indices, including conventional (bootstrap or cross-validation based) and emerging (modularity-based) validation indices for general clustering methods as well as the specific one (Xie and Beni) for fuzzy clustering. The MIV performance was demonstrated on a big longitudinal dataset from a real web-delivered trial and using simulation. The results indicate MI-based Xie and Beni index for fuzzy-clustering are more appropriate for detecting the optimal number of clusters for such complex data. The MIV concept and algorithms could be easily adapted to different types of clustering that could process big incomplete longitudinal trial data in eHealth services.

Multiple Imputation based Clustering Validation (MIV) for Big Longitudinal Trial Data with Missing Values in eHealth

PubMed Central

Zhang, Zhaoyang; Wang, Honggang

2016-01-01

Web-delivered trials are an important component in eHealth services. These trials, mostly behavior-based, generate big heterogeneous data that are longitudinal, high dimensional with missing values. Unsupervised learning methods have been widely applied in this area, however, validating the optimal number of clusters has been challenging. Built upon our multiple imputation (MI) based fuzzy clustering, MIfuzzy, we proposed a new multiple imputation based validation (MIV) framework and corresponding MIV algorithms for clustering big longitudinal eHealth data with missing values, more generally for fuzzy-logic based clustering methods. Specifically, we detect the optimal number of clusters by auto-searching and -synthesizing a suite of MI-based validation methods and indices, including conventional (bootstrap or cross-validation based) and emerging (modularity-based) validation indices for general clustering methods as well as the specific one (Xie and Beni) for fuzzy clustering. The MIV performance was demonstrated on a big longitudinal dataset from a real web-delivered trial and using simulation. The results indicate MI-based Xie and Beni index for fuzzy-clustering is more appropriate for detecting the optimal number of clusters for such complex data. The MIV concept and algorithms could be easily adapted to different types of clustering that could process big incomplete longitudinal trial data in eHealth services. PMID:27126063

Total marrow irradiation using Helical TomoTherapy

NASA Astrophysics Data System (ADS)

Garcia-Fernandez, Lourdes Maria

Clinical dose response data of human tumours are limited or restricted to a radiation dose range determined by the level of toxicity to the normal tissues. This is the case for the most common disseminated plasma cell neoplasm, multiple myeloma, where the maximum dose deliverable to the entire bony skeleton using a standard total body irradiation (TBI) technique is limited to about 12 Gy. This study is part of scientific background of a phase I/II dose escalation clinical trial for multiple myeloma using image-guided intensity modulated radiotherapy (IG-IMRT) to deliver high dose to the entire volume of bone marrow with Helical TomoTherapy (HT). This relatively new technology can deliver highly conformal dose distributions to complex target shapes while reducing the dose to critical normal tissues. In this study tools for comparing and predicting the effectiveness of different approaches to total marrow irradiation (TMI) using HT were provided. The expected dose response for plasma cell neoplasms was computed and a radiobiological evaluation of different treatment cohorts in a dose escalating study was performed. Normal tissue complication probability (NTCP) and tumour control probability (TCP) models were applied to an actual TMI treatment plan for a patient and the implications of using different longitudinal field widths were assessed. The optimum dose was ˜39 Gy for which a predicted tumour control of 95% (+/-3%) was obtained, with a predicted 3% (0, 8%) occurrence of radiation pneumonitis. Tissue sparing was seen by using smaller field widths only in the organs of the head. This suggests it would be beneficial to use the small fields in the head only since using small fields for the whole treatment would lead to long treatment times. In TMI it may be necessary to junction two longitudinally adjacent treatment volumes to form a contiguous planning target volume PTV. For instance, this is the case when a different SUP-INF spatial resolution is required or when the PTV length exceeds the bed travel distance. In this work, the dosimetric challenges associated with junctioning longitudinally adjacent PTVs with HT were analyzed and the feasibility of PTV junctioning was demonstrated. The benefits of spatially dividing or splitting the treatment into a few sub-treatments along the longitudinal direction were also investigated.

Cognitive decline and brain volume loss are signatures of cerebral Aβ deposition identified with PIB

PubMed Central

Storandt, Martha; Mintun, Mark A.; Head, Denise; Morris, John C.

2009-01-01

Objective To examine the relation of amyloid-beta (Aβ) levels in cerebral cortex with structural brain integrity and cognitive performance in older people with a Clinical Dementia Rating (CDR) of 0 (cognitively normal). Methods The relations between mean cortical [11C] PIB binding potential values, proportional to the density of fibrillar Aβ binding sites in the brain, concurrent regional brain volumes as assessed by magnetic resonance imaging, and both concurrent and longitudinal (up to 19 years) cognitive performance in multiple domains were examined in 135 CDR 0 individuals aged 65 to 88 years. Results Elevated cerebral Aβ levels, in some cases comparable to that seen in individuals with Alzheimer's disease, were observed in 29 CDR 0 individuals. Significantly smaller regional volumes in the hippocampus, temporal neocortex, anterior cingulate, and posterior cingulate were observed in these CDR 0 individuals with elevated Aβ levels. Concurrent cognitive performance was unrelated to Aβ levels but was related to regional brain volumes with the exception of caudate. Longitudinal cognitive decline was associated with elevated Aβ levels and decreased hippocampal volume. Decline was not limited to episodic memory but included working memory and visuospatial abilities as well. Interpretation [11C] PIB, an in vivo measure of cerebral amyloidosis, is associated with regionally specific brain atrophy cross-sectionally and a pattern of longitudinal cognitive decline in multiple cognitive domains that occurs prior to the clinical diagnosis of Alzheimer' disease. These findings contribute to the understanding of the cognitive and structural consequences of Aβ levels in CDR 0 older adults. PMID:20008651

Longitudinal Associations between Observed and Perceived Neighborhood Food Availability and Body Mass Index in a Multiethnic Urban Sample

ERIC Educational Resources Information Center

Zenk, Shannon N.; Mentz, Graciela; Schulz, Amy J.; Johnson-Lawrence, Vicki; Gaines, Causandra R.

2017-01-01

Introduction: Blacks, Hispanics, and women of lower socioeconomic status tend to have a higher risk of obesity. Numerous studies over the past decade examined the role of the neighborhood food environment in body weight. However, few were longitudinal. Purpose: This longitudinal study examined whether multiple measures of neighborhood food…

Neurodevelopmental outcome in patients with terminal deletion of the short arm of chromosome 20

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frazer, C.H.; Hobbs, N.; Rappaport, L.

Clinical geneticists and genetic counselors are often expected to provide information concerning anticipated neurodevelopmental outcome in children with chromosome abnormalities. Accurate prediction, however, may be impossible, and is at the least hampered by insufficient data and by natural variation in expression. Our experience with a now 27-month-old boy with terminal 20p- underscores this issue. A newborn male with multiple congenital anomalies, including pulmonary artery stenosis, vertebral anomalies, posterior ocular embryotoxon and multiple dysmorphic features was found to have 46,XY,del(20)(p11.23ter) de novo, including the location for Alagille Syndrome (AS). Early clinical course was also notable for obstructive apnea and cardiorespiratory arrests.more » Available literature suggested a poor neurodevelopmental prognosis. At age 27 months, he exhibits hypotonia and gross motor skills assessed at 12-15 months. However, cognitive and language skills were at the 20 months level. No structural neurological lesions have been identified. We attempted to obtain updated outcome information on previous cases for comparison. 11 previously published reports with similar extent of deletion of 20p demonstrated varied, but often more severe neurodevelopmental impairment. The majority described early global delays, with significant motor delay. However, little longitudinal or functional information was available. In contrast, our patient demonstrates good neurodevelopmental and functional progress. Caution should be exercised in counseling regarding neurodevelopmental outcome in cases of chromosomal anomaly, due to lack of information and natural variability. Standardized assessment and reporting of longitudinal neurodevelopmental follow-up are necessary for more appropriate counseling concerning outcome in chromosomal anomalies.« less

The MONET code for the evaluation of the dose in hadrontherapy

NASA Astrophysics Data System (ADS)

Embriaco, A.

2018-01-01

The MONET is a code for the computation of the 3D dose distribution for protons in water. For the lateral profile, MONET is based on the Molière theory of multiple Coulomb scattering. To take into account also the nuclear interactions, we add to this theory a Cauchy-Lorentz function, where the two parameters are obtained by a fit to a FLUKA simulation. We have implemented the Papoulis algorithm for the passage from the projected to a 2D lateral distribution. For the longitudinal profile, we have implemented a new calculation of the energy loss that is in good agreement with simulations. The inclusion of the straggling is based on the convolution of energy loss with a Gaussian function. In order to complete the longitudinal profile, also the nuclear contributions are included using a linear parametrization. The total dose profile is calculated in a 3D mesh by evaluating at each depth the 2D lateral distributions and by scaling them at the value of the energy deposition. We have compared MONET with FLUKA in two cases: a single Gaussian beam and a lateral scan. In both cases, we have obtained a good agreement for different energies of protons in water.

New Methods to Address Old Challenges: The Use of Administrative Data for Longitudinal Replication Studies of Child Maltreatment

PubMed Central

Hurren, Emily; Stewart, Anna; Dennison, Susan

2017-01-01

Administrative data are crucial to the “big data” revolution of social science and have played an important role in the development of child maltreatment research. These data are also of value to administrators, policy makers, and clinicians. The focus of this paper is the use of administrative data to produce and replicate longitudinal studies of child maltreatment. Child protection administrative data have several advantages. They are often population-based, and allow longitudinal examination of child maltreatment and complex multi-level analyses. They also allow comparison across subgroups and minority groups, remove burden from individuals to disclose traumatic experiences, and can be less biased than retrospective recall. Finally, they can be linked to data from other agencies to explore comorbidity and outcomes, and are comparatively cost and time effective. The benefits and challenges associated with the use of administrative data for longitudinal child maltreatment research become magnified when these data are used to produce replications. Techniques to address challenges and support future replication efforts include developing a biographical understanding of the systems from which the data are drawn, using multiple data sources to contextualize the data and research results, recognizing and adopting various approaches to replication, and documenting all data coding and manipulation processes. These techniques are illustrated in this paper via a case study of previous replication work. PMID:28914775

New Methods to Address Old Challenges: The Use of Administrative Data for Longitudinal Replication Studies of Child Maltreatment.

PubMed

Hurren, Emily; Stewart, Anna; Dennison, Susan

2017-09-15

Administrative data are crucial to the "big data" revolution of social science and have played an important role in the development of child maltreatment research. These data are also of value to administrators, policy makers, and clinicians. The focus of this paper is the use of administrative data to produce and replicate longitudinal studies of child maltreatment. Child protection administrative data have several advantages. They are often population-based, and allow longitudinal examination of child maltreatment and complex multi-level analyses. They also allow comparison across subgroups and minority groups, remove burden from individuals to disclose traumatic experiences, and can be less biased than retrospective recall. Finally, they can be linked to data from other agencies to explore comorbidity and outcomes, and are comparatively cost and time effective. The benefits and challenges associated with the use of administrative data for longitudinal child maltreatment research become magnified when these data are used to produce replications. Techniques to address challenges and support future replication efforts include developing a biographical understanding of the systems from which the data are drawn, using multiple data sources to contextualize the data and research results, recognizing and adopting various approaches to replication, and documenting all data coding and manipulation processes. These techniques are illustrated in this paper via a case study of previous replication work.

A longitudinal study of self-control at the transition to secondary school: Considering the role of pubertal status and parenting.

PubMed

Ng-Knight, Terry; Shelton, Katherine H; Riglin, Lucy; McManus, I C; Frederickson, Norah; Rice, Frances

2016-07-01

Higher self-control in children and adolescents is associated with a range of positive outcomes in adulthood. However, little is known about the naturalistic development of self-control during early adolescence and the factors that affect this. We examined the role of puberty and parenting style as theoretically important influences on stability and change in self-control. A longitudinal (3 waves), multiple-informant dataset of children entering early adolescence (M = 11 years) was used to explore longitudinal change in self-control using latent growth curve modelling. Children's self-control declined during the one-year study period and declines were associated with children's behavioural and social functioning. Associations with self-control were found for pubertal status and parental warmth and hostility, but not for parental discipline. The findings suggest that during early adolescence, when children make the transition to secondary school, self-control declines. This is particularly the case for those experiencing puberty earlier than their peers. Parent warmth influences the trajectory of self-control during this period. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Bayesian quantile regression-based partially linear mixed-effects joint models for longitudinal data with multiple features.

PubMed

Zhang, Hanze; Huang, Yangxin; Wang, Wei; Chen, Henian; Langland-Orban, Barbara

2017-01-01

In longitudinal AIDS studies, it is of interest to investigate the relationship between HIV viral load and CD4 cell counts, as well as the complicated time effect. Most of common models to analyze such complex longitudinal data are based on mean-regression, which fails to provide efficient estimates due to outliers and/or heavy tails. Quantile regression-based partially linear mixed-effects models, a special case of semiparametric models enjoying benefits of both parametric and nonparametric models, have the flexibility to monitor the viral dynamics nonparametrically and detect the varying CD4 effects parametrically at different quantiles of viral load. Meanwhile, it is critical to consider various data features of repeated measurements, including left-censoring due to a limit of detection, covariate measurement error, and asymmetric distribution. In this research, we first establish a Bayesian joint models that accounts for all these data features simultaneously in the framework of quantile regression-based partially linear mixed-effects models. The proposed models are applied to analyze the Multicenter AIDS Cohort Study (MACS) data. Simulation studies are also conducted to assess the performance of the proposed methods under different scenarios.

Success in health information exchange projects: solving the implementation puzzle.

PubMed

Sicotte, Claude; Paré, Guy

2010-04-01

Interest in health information exchange (HIE), defined as the use of information technology to support the electronic transfer of clinical information across health care organizations, continues to grow among those pursuing greater patient safety and health care accessibility and efficiency. In this paper, we present the results of a longitudinal multiple-case study of two large-scale HIE implementation projects carried out in real time over 3-year and 2-year periods in Québec, Canada. Data were primarily collected through semi-structured interviews (n=52) with key informants, namely implementation team members and targeted users. These were supplemented with non-participants observation of team meetings and by the analysis of organizational documents. The cross-case comparison was particularly relevant given that project circumstances led to contrasting outcomes: while one project failed, the other was a success. A risk management analysis was performed taking a process view in order to capture the complexity of project implementations as evolving phenomena that are affected by interdependent pre-existing and emergent risks that tend to change over time. The longitudinal case analysis clearly demonstrates that the risk factors were closely intertwined. Systematic ripple effects from one risk factor to another were observed. This risk interdependence evolved dynamically over time, with a snowball effect that rendered a change of path progressively more difficult as time passed. The results of the cross-case analysis demonstrate a direct relationship between the quality of an implementation strategy and project outcomes. Copyright 2010 Elsevier Ltd. All rights reserved.

Estimating increment-decrement life tables with multiple covariates from panel data: the case of active life expectancy.

PubMed

Land, K C; Guralnik, J M; Blazer, D G

1994-05-01

A fundamental limitation of current multistate life table methodology-evident in recent estimates of active life expectancy for the elderly-is the inability to estimate tables from data on small longitudinal panels in the presence of multiple covariates (such as sex, race, and socioeconomic status). This paper presents an approach to such an estimation based on an isomorphism between the structure of the stochastic model underlying a conventional specification of the increment-decrement life table and that of Markov panel regression models for simple state spaces. We argue that Markov panel regression procedures can be used to provide smoothed or graduated group-specific estimates of transition probabilities that are more stable across short age intervals than those computed directly from sample data. We then join these estimates with increment-decrement life table methods to compute group-specific total, active, and dependent life expectancy estimates. To illustrate the methods, we describe an empirical application to the estimation of such life expectancies specific to sex, race, and education (years of school completed) for a longitudinal panel of elderly persons. We find that education extends both total life expectancy and active life expectancy. Education thus may serve as a powerful social protective mechanism delaying the onset of health problems at older ages.

Multivariate analysis of longitudinal rates of change.

PubMed

Bryan, Matthew; Heagerty, Patrick J

2016-12-10

Longitudinal data allow direct comparison of the change in patient outcomes associated with treatment or exposure. Frequently, several longitudinal measures are collected that either reflect a common underlying health status, or characterize processes that are influenced in a similar way by covariates such as exposure or demographic characteristics. Statistical methods that can combine multivariate response variables into common measures of covariate effects have been proposed in the literature. Current methods for characterizing the relationship between covariates and the rate of change in multivariate outcomes are limited to select models. For example, 'accelerated time' methods have been developed which assume that covariates rescale time in longitudinal models for disease progression. In this manuscript, we detail an alternative multivariate model formulation that directly structures longitudinal rates of change and that permits a common covariate effect across multiple outcomes. We detail maximum likelihood estimation for a multivariate longitudinal mixed model. We show via asymptotic calculations the potential gain in power that may be achieved with a common analysis of multiple outcomes. We apply the proposed methods to the analysis of a trivariate outcome for infant growth and compare rates of change for HIV infected and uninfected infants. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A model for incomplete longitudinal multivariate ordinal data.

PubMed

Liu, Li C

2008-12-30

In studies where multiple outcome items are repeatedly measured over time, missing data often occur. A longitudinal item response theory model is proposed for analysis of multivariate ordinal outcomes that are repeatedly measured. Under the MAR assumption, this model accommodates missing data at any level (missing item at any time point and/or missing time point). It allows for multiple random subject effects and the estimation of item discrimination parameters for the multiple outcome items. The covariates in the model can be at any level. Assuming either a probit or logistic response function, maximum marginal likelihood estimation is described utilizing multidimensional Gauss-Hermite quadrature for integration of the random effects. An iterative Fisher-scoring solution, which provides standard errors for all model parameters, is used. A data set from a longitudinal prevention study is used to motivate the application of the proposed model. In this study, multiple ordinal items of health behavior are repeatedly measured over time. Because of a planned missing design, subjects answered only two-third of all items at a given point. Copyright 2008 John Wiley & Sons, Ltd.

Multiple social identifications and adolescents' self-esteem.

PubMed

Benish-Weisman, Maya; Daniel, Ella; Schiefer, David; Möllering, Anna; Knafo-Noam, Ariel

2015-10-01

The research examined the relationship between multiple social identifications and self-esteem. Early adolescents (M = 11.4, SD = .95) and mid-adolescents (M = 15.9, SD = 1.18) from Germany and Israel (n = 2337) were studied. Respondents described their social identification as students, family members, and as members of the majority national group and reported self-esteem. A longitudinal, cross-sectional and cross-cultural design revealed, as predicted, multiple social identifications related positively to self-esteem concurrently; they also related positively to self-esteem longitudinally over the course of a year. Moreover, multiple social identifications were found to be antecedent to self-esteem, not vice versa. Finally, multiple social identifications were found to decrease over time. The article discusses the contribution of multiple social identifications to self-esteem at different ages and in various contexts. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Antenatal Workup of Early Megacystis and Selection of Candidates for Fetal Therapy.

PubMed

Fontanella, Federica; Duin, Leonie; Adama van Scheltema, Phebe N; Cohen-Overbeek, Titia E; Pajkrt, Eva; Bekker, Mireille; Willekes, Christine; Bax, Caroline J; Oepkes, Dick; Bilardo, Catia M

2018-05-17

To investigate the best criteria for discriminating fetuses with isolated posterior urethral valves from those theoretically not eligible for fetal treatment because of complex megacystis, high chance of spontaneous resolution, and urethral atresia. A retrospective national study was conducted in fetuses with megacystis detected before 17 weeks' gestation (early megacystis). In total, 142 cases with fetal megacystis were included in the study: 52 with lower urinary tract obstruction, 29 with normal micturition at birth, and 61 with miscellaneous syndromal associations, chromosomal and multiple structural abnormalities (complex megacystis). Only a nuchal translucency > 95th centile, and not a longitudinal bladder diameter ≤15 mm (p = 0.24), significantly increased the risk of complex megacystis (p < 0.01). Cases with a high chance of spontaneous resolution were identified by using the cut-off of 12 mm, as demonstrated in a previous study, and the finding of an associated umbilical cord cyst carried a high-risk of urethral atresia (odds ratio: 15; p = 0.026), an unfavorable condition for antenatal treatment. An algorithm encompassing these three criteria demonstrated good accuracy in selecting fetuses theoretically eligible for fetal treatment (specificity 73%; sensitivity 92%). Cases theoretically eligible for early fetal therapy are those with normal nuchal translucency, a longitudinal bladder diameter > 12 mm, and without ultrasound evidence of umbilical cord cysts. © 2018 The Author(s) Published by S. Karger AG, Basel.

Clinical Pharmacology Quality Assurance (CPQA) Program: Models for Longitudinal Analysis of Antiretroviral (ARV) Proficiency Testing for International Laboratories

PubMed Central

DiFrancesco, Robin; Rosenkranz, Susan L.; Taylor, Charlene R.; Pande, Poonam G.; Siminski, Suzanne M.; Jenny, Richard W.; Morse, Gene D.

2013-01-01

Among National Institutes of Health (NIH) HIV Research Networks conducting multicenter trials, samples from protocols that span several years are analyzed at multiple clinical pharmacology laboratories (CPLs) for multiple antiretrovirals (ARV). Drug assay data are, in turn, entered into study-specific datasets that are used for pharmacokinetic analyses, merged to conduct cross-protocol pharmacokinetic analysis and integrated with pharmacogenomics research to investigate pharmacokinetic-pharmacogenetic associations. The CPLs participate in a semi-annual proficiency testing (PT) program implemented by the Clinical Pharmacology Quality Assurance (CPQA) program. Using results from multiple PT rounds, longitudinal analyses of recovery are reflective of accuracy and precision within/across laboratories. The objectives of this longitudinal analysis of PT across multiple CPLs were to develop and test statistical models that longitudinally: (1)assess the precision and accuracy of concentrations reported by individual CPLs; (2)determine factors associated with round-specific and long-term assay accuracy, precision and bias using a new regression model. A measure of absolute recovery is explored as a simultaneous measure of accuracy and precision. Overall, the analysis outcomes assured 97% accuracy (±20% of the final target concentration of all (21)drug concentration results reported for clinical trial samples by multiple CPLs).Using the CLIA acceptance of meeting criteria for ≥2/3 consecutive rounds, all ten laboratories that participated in three or more rounds per analyte maintained CLIA proficiency. Significant associations were present between magnitude of error and CPL (Kruskal Wallis [KW]p<0.001), and ARV (KW p<0.001). PMID:24052065

Clinical pharmacology quality assurance program: models for longitudinal analysis of antiretroviral proficiency testing for international laboratories.

PubMed

DiFrancesco, Robin; Rosenkranz, Susan L; Taylor, Charlene R; Pande, Poonam G; Siminski, Suzanne M; Jenny, Richard W; Morse, Gene D

2013-10-01

Among National Institutes of Health HIV Research Networks conducting multicenter trials, samples from protocols that span several years are analyzed at multiple clinical pharmacology laboratories (CPLs) for multiple antiretrovirals. Drug assay data are, in turn, entered into study-specific data sets that are used for pharmacokinetic analyses, merged to conduct cross-protocol pharmacokinetic analysis, and integrated with pharmacogenomics research to investigate pharmacokinetic-pharmacogenetic associations. The CPLs participate in a semiannual proficiency testing (PT) program implemented by the Clinical Pharmacology Quality Assurance program. Using results from multiple PT rounds, longitudinal analyses of recovery are reflective of accuracy and precision within/across laboratories. The objectives of this longitudinal analysis of PT across multiple CPLs were to develop and test statistical models that longitudinally: (1) assess the precision and accuracy of concentrations reported by individual CPLs and (2) determine factors associated with round-specific and long-term assay accuracy, precision, and bias using a new regression model. A measure of absolute recovery is explored as a simultaneous measure of accuracy and precision. Overall, the analysis outcomes assured 97% accuracy (±20% of the final target concentration of all (21) drug concentration results reported for clinical trial samples by multiple CPLs). Using the Clinical Laboratory Improvement Act acceptance of meeting criteria for ≥2/3 consecutive rounds, all 10 laboratories that participated in 3 or more rounds per analyte maintained Clinical Laboratory Improvement Act proficiency. Significant associations were present between magnitude of error and CPL (Kruskal-Wallis P < 0.001) and antiretroviral (Kruskal-Wallis P < 0.001).

Coding response to a case-mix measurement system based on multiple diagnoses.

PubMed

Preyra, Colin

2004-08-01

To examine the hospital coding response to a payment model using a case-mix measurement system based on multiple diagnoses and the resulting impact on a hospital cost model. Financial, clinical, and supplementary data for all Ontario short stay hospitals from years 1997 to 2002. Disaggregated trends in hospital case-mix growth are examined for five years following the adoption of an inpatient classification system making extensive use of combinations of secondary diagnoses. Hospital case mix is decomposed into base and complexity components. The longitudinal effects of coding variation on a standard hospital payment model are examined in terms of payment accuracy and impact on adjustment factors. Introduction of the refined case-mix system provided incentives for hospitals to increase reporting of secondary diagnoses and resulted in growth in highest complexity cases that were not matched by increased resource use over time. Despite a pronounced coding response on the part of hospitals, the increase in measured complexity and case mix did not reduce the unexplained variation in hospital unit cost nor did it reduce the reliance on the teaching adjustment factor, a potential proxy for case mix. The main implication was changes in the size and distribution of predicted hospital operating costs. Jurisdictions introducing extensive refinements to standard diagnostic related group (DRG)-type payment systems should consider the effects of induced changes to hospital coding practices. Assessing model performance should include analysis of the robustness of classification systems to hospital-level variation in coding practices. Unanticipated coding effects imply that case-mix models hypothesized to perform well ex ante may not meet expectations ex post.

Accelerated longitudinal designs: An overview of modelling, power, costs and handling missing data.

PubMed

Galbraith, Sally; Bowden, Jack; Mander, Adrian

2017-02-01

Longitudinal studies are often used to investigate age-related developmental change. Whereas a single cohort design takes a group of individuals at the same initial age and follows them over time, an accelerated longitudinal design takes multiple single cohorts, each one starting at a different age. The main advantage of an accelerated longitudinal design is its ability to span the age range of interest in a shorter period of time than would be possible with a single cohort longitudinal design. This paper considers design issues for accelerated longitudinal studies. A linear mixed effect model is considered to describe the responses over age with random effects for intercept and slope parameters. Random and fixed cohort effects are used to cope with the potential bias accelerated longitudinal designs have due to multiple cohorts. The impact of other factors such as costs and the impact of dropouts on the power of testing or the precision of estimating parameters are examined. As duration-related costs increase relative to recruitment costs the best designs shift towards shorter duration and eventually cross-sectional design being best. For designs with the same duration but differing interval between measurements, we found there was a cutoff point for measurement costs relative to recruitment costs relating to frequency of measurements. Under our model of 30% dropout there was a maximum power loss of 7%.

Brain mechanisms of recovery from pure alexia: A single case study with multiple longitudinal scans.

PubMed

Cohen, Laurent; Dehaene, Stanislas; McCormick, Samantha; Durant, Szonya; Zanker, Johannes M

2016-10-01

Pure alexia is an acquired reading disorder, typically due to a left occipito-temporal lesion affecting the Visual Word Form Area (VWFA). It is unclear whether the VWFA acts as a unique bottleneck for reading, or whether alternative routes are available for recovery. Here, we address this issue through the single-case longitudinal study of a neuroscientist who experienced pure alexia and participated in 17 behavioral, 9 anatomical, and 9 fMRI assessment sessions over a period of two years. The origin of the impairment was assigned to a small left fusiform lesion, accompanied by a loss of VWFA responsivity and by the degeneracy of the associated white matter pathways. fMRI experiments allowed us to image longitudinally the visual perception of words, as compared to other classes of stimuli, as well as the mechanisms of letter-by-letter reading. The progressive improvement of reading was not associated with the re-emergence of a new area selective to words, but with increasing responses in spared occipital cortex posterior to the lesion and in contralateral right occipital cortex. Those regions showed a non-specific increase of activations over time and an increase in functional correlation with distant language areas. Those results confirm the existence of an alternative occipital route for reading, bypassing the VWFA, but they also point to its key limitation: the patient remained a slow letter-by-letter reader, thus supporting the critical importance of the VWFA for the efficient parallel recognition of written words. Copyright © 2016 Elsevier Ltd. All rights reserved.

Studying the Longitudinal Study. I. Introduction: Do Impromptu Essays Show Changes in Critical Thinking over the Span of College? Cautions and Insights from a Pilot Case Study.

ERIC Educational Resources Information Center

Clark, Francelia

The problematic results of longitudinal studies on college writing indicate the need for multidimensional studies to be able to explore perceptible changes in students' writing. Accordingly a small pilot case study, to explore the promise and the limitations of doing a longitudinal multidimensional study, investigated whether impromptu essays…

Lifestyle in Multiple Myeloma - a longitudinal cohort study protocol.

PubMed

Heinrich, M; Fisher, A; Paton, B; McCourt, O; Beeken, R J; Hackshaw, A; Wardle, J; Yong, K

2016-07-04

Deterioration in bone health is one of the presenting symptoms of Multiple Myeloma (MM), a cancer of plasma cells. As a consequence of this condition, patients suffer bone pain and bone damage and report cancer-related fatigue, resulting in deterioration in their quality of life. Evidence in patients with solid tumours shows promise for the positive effects of physical activity on quality of life. However, in the case of patients with MM a better understanding of the association between physical fitness and quality of life factors is still required. Therefore, this cohort study aims to objectively and longitudinally assess activity and fitness levels in patients with MM in order to explore their role in bone health, fatigue and quality of life for this patient population. The study is a prospective cohort study of MM patients in remission to assess physical activity, fatigue and bone health. Clinical markers of health, self-reported measures of psychological and physical well-being, and lifestyle behaviours are assessed at baseline, 3, 6 and 12 months. At each time point, patients complete cardiopulmonary exercise testing (CPET) along with a series of objective tests to assess physical fitness (eg accelerometry) and a number of self-report measures. A complementary qualitative study will be carried out in order to explore patients' desire for lifestyle advice and when in their cancer journey they deem such advice to be useful. This study will be the first to prospectively and longitudinally explore associations between physical fitness and well-being, bone health, and fatigue (along with a number of other physical and clinical outcomes) in a cohort of patients with MM with the use of objective measures. The findings will also help to identify time points within the MM pathway at which physical activity interventions may be introduced for maximum benefit.

Case Manager Perspectives on the Role of Treatment in Supportive Housing for People with Severe Mental Illness

PubMed Central

Stanhope, Victoria; Choy-Brown, Mimi; Tiderington, Emmy; Henwood, Benjamin F.; Padgett, Deborah K.

2016-01-01

Objective Growing recognition exists of housing as a social determinant of health, and thus, health care reform initiatives are expanding the reach of health care beyond traditional settings. One result of this expansion is increased Medicaid funds for supportive-housing programs for people with severe mental illnesses. This qualitative study explores the ways in which case managers working in a supportive housing program approach treatment and how their approach is influenced by both program requirements and their beliefs about mental illness. Method The study is part of a longitudinal qualitative study on recovery for people with severe mental illnesses living in supportive housing. Multiple interviews (n = 55) with 24 case managers from a residential-continuum supportive-housing program were conducted over 18 months. To provide an in-depth view of case manager perspectives, the study uses thematic analysis with multiple coders. Results Overall, case managers understand supportive housing as being a treatment program but predominantly characterize treatment as medication management. The following themes emerged: believing medication to be the key to success in the program, persuading residents to take medication, and questioning the utility of the program for residents who were not medication adherent. Conclusions Case managers understand supportive housing to be a treatment program; however, given the external constraints and their own beliefs about mental illness, case managers often equate treatment with taking medication. Study findings demonstrate the need to train case managers about mental health recovery and integrated health care. The findings also have implications for policies that tie housing to services. PMID:28163830

EU-AIMS Longitudinal European Autism Project (LEAP): the autism twin cohort.

PubMed

Isaksson, Johan; Tammimies, Kristiina; Neufeld, Janina; Cauvet, Élodie; Lundin, Karl; Buitelaar, Jan K; Loth, Eva; Murphy, Declan G M; Spooren, Will; Bölte, Sven

2018-01-01

EU-AIMS is the largest European research program aiming to identify stratification biomarkers and novel interventions for autism spectrum disorder (ASD). Within the program, the Longitudinal European Autism Project (LEAP) has recruited and comprehensively phenotyped a rare sample of 76 monozygotic and dizygotic twins, discordant, or concordant for ASD plus 30 typically developing twins. The aim of this letter is to complete previous descriptions of the LEAP case-control sample, clinically characterize, and investigate the suitability of the sample for ASD twin-control analyses purposes and share some 'lessons learnt.' Among the twins, a diagnosis of ASD is associated with increased symptom levels of ADHD, higher rates of intellectual disability, and lower family income. For the future, we conclude that the LEAP twin cohort offers multiple options for analyses of genetic and shared and non-shared environmental factors to generate new hypotheses for the larger cohort of LEAP singletons, but particularly cross-validate and refine evidence from it.

POSTOP: Postbuckled open-stiffener optimum panels-theory and capability

NASA Technical Reports Server (NTRS)

Dickson, J. N.; Biggers, S. B.

1984-01-01

The computer program POSTOP was developed to serve as an aid in the analysis and sizing of stiffened composite panels that are loaded in the postbuckling regime. A comprehensive set of analysis routines was coupled to a widely used optimization program to produce this sizing code. POSTOP is intended for the preliminary design of metal or composite panels with open-section stiffeners, subjected to multiple combined biaxial compression (or tension), shear and normal pressure load cases. Longitudinal compression, however, is assumed to be the dominant loading. Temperature, initial bow eccentricity and load eccentricity effects are included. The panel geometry is assumed to be repetitive over several bays in the longitudinal (stiffener) direction as well as in the transverse direction. Analytical routines are included to compute panel stiffnesses, strains, local and panel buckling loads, and skin/stiffener interface stresses. The resulting program is applicable to stiffened panels as commonly used in fuselage, wing, or empennage structures. The analysis procedures and rationale for the assumptions used therein are described in detail.

[SPECIFIC DIAGNOSTIC SIGNIFICANCE OF "RIPPLE SIGN" OF MEDIAL FEMORAL CONDYLE UNDER ARTHROSCOPE IN MEDIAL LONGITUDINAL MENISCAL TEARS].

PubMed

Ren Shiyou; Sun, Limang; Chen, Guofei; Jiang, Changqing; Zhang, Xintao; Zhang Wentao

2015-01-01

To investigate the reliability of the "ripple sign" on the upper surface of the medial femoral condyle in the diagnosis of medial longitudinal meniscal tears under arthroscope. Between June 2013 and June 2014, 56 patients with knee injuries were included. There were 35 males and 21 females with an average age of 22.2 years (range, 12-38 years). The causes of injury were sports in 40 cases, falling in 10 cases, and traffic accident in 6 cases. The injury was located at the left knee in 22 cases and at the right knee in 34 cases. The disease duration was 10-40 days (mean, 20.2 days). Of 56 patients, 15 cases had simple medial meniscal injury; 41 cases had combined injuries, including anterior cruciate ligament injury in 38 cases, posterior cruciate ligament injury in 2 cases, and patellar dislocation in 1 case. The "ripple sign" was observed under arthroscope before operation. Repair of medial meniscal injury and reconstruction of cruciate ligament were performed. The positive "ripple sign" was seen under arthroscope in all patients, who were diagnosed to have longitudinal meniscal tears, including 23 cases of mild "ripple sign" , 28 cases of moderate "ripple sign", and 5 cases of severe "ripple sign". The "ripple sign" on the upper surface of the medial femoral condyle is a reliable diagnostic evidence of medial longitudinal meniscal tears.

Multivariate Analysis of Longitudinal Rates of Change

PubMed Central

Bryan, Matthew; Heagerty, Patrick J.

2016-01-01

Longitudinal data allow direct comparison of the change in patient outcomes associated with treatment or exposure. Frequently, several longitudinal measures are collected that either reflect a common underlying health status, or characterize processes that are influenced in a similar way by covariates such as exposure or demographic characteristics. Statistical methods that can combine multivariate response variables into common measures of covariate effects have been proposed by Roy and Lin [1]; Proust-Lima, Letenneur and Jacqmin-Gadda [2]; and Gray and Brookmeyer [3] among others. Current methods for characterizing the relationship between covariates and the rate of change in multivariate outcomes are limited to select models. For example, Gray and Brookmeyer [3] introduce an “accelerated time” method which assumes that covariates rescale time in longitudinal models for disease progression. In this manuscript we detail an alternative multivariate model formulation that directly structures longitudinal rates of change, and that permits a common covariate effect across multiple outcomes. We detail maximum likelihood estimation for a multivariate longitudinal mixed model. We show via asymptotic calculations the potential gain in power that may be achieved with a common analysis of multiple outcomes. We apply the proposed methods to the analysis of a trivariate outcome for infant growth and compare rates of change for HIV infected and uninfected infants. PMID:27417129

Explicating the Conditions Under Which Multilevel Multiple Imputation Mitigates Bias Resulting from Random Coefficient-Dependent Missing Longitudinal Data.

PubMed

Gottfredson, Nisha C; Sterba, Sonya K; Jackson, Kristina M

2017-01-01

Random coefficient-dependent (RCD) missingness is a non-ignorable mechanism through which missing data can arise in longitudinal designs. RCD, for which we cannot test, is a problematic form of missingness that occurs if subject-specific random effects correlate with propensity for missingness or dropout. Particularly when covariate missingness is a problem, investigators typically handle missing longitudinal data by using single-level multiple imputation procedures implemented with long-format data, which ignores within-person dependency entirely, or implemented with wide-format (i.e., multivariate) data, which ignores some aspects of within-person dependency. When either of these standard approaches to handling missing longitudinal data is used, RCD missingness leads to parameter bias and incorrect inference. We explain why multilevel multiple imputation (MMI) should alleviate bias induced by a RCD missing data mechanism under conditions that contribute to stronger determinacy of random coefficients. We evaluate our hypothesis with a simulation study. Three design factors are considered: intraclass correlation (ICC; ranging from .25 to .75), number of waves (ranging from 4 to 8), and percent of missing data (ranging from 20 to 50%). We find that MMI greatly outperforms the single-level wide-format (multivariate) method for imputation under a RCD mechanism. For the MMI analyses, bias was most alleviated when the ICC is high, there were more waves of data, and when there was less missing data. Practical recommendations for handling longitudinal missing data are suggested.

Dovetail spoke internal permanent magnet machine

DOEpatents

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-08-23

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

Longitudinal erythronychia: individual or multiple linear red bands of the nail plate: a review of clinical features and associated conditions.

PubMed

Cohen, Philip R

2011-08-01

Longitudinal erythronychia is a linear red band on the nail plate that originates at the proximal nail fold, traverses the lunula, and extends to the free edge of the nail plate. Longitudinal erythronychia is classified based upon the number of nails affected and the number of red streaks present on each nail as follows: type Ia (monodactylous - single band), type Ib (monodactylous - bifid bands), type IIa (polydactylous - single band), and type IIb (polydactylous - multiple bands). Associated morphologic findings that can be present at the distal tip of the nail with longitudinal erythronychia include fragility, onycholysis, splinter hemorrhage, splitting, subungual keratosis, thinning, and V-shaped nick. Some patients with longitudinal erythronychia seek medical evaluation because of pain in the associated distal digit; however, the linear red nail plate dyschromia is often asymptomatic and the individual is concerned about the cosmetic appearance or distal nail fragility. Longitudinal erythronychia can be a clinical manifestation of an underlying local or systemic condition. Benign tumors (glomus tumor, onychopapilloma, and warty dyskeratoma), malignant neoplasms (malignant melanoma and squamous cell carcinoma), and other conditions (hemiplegia and postsurgical scar) can be associated with monodactylous longitudinal erythronychia or it may be idiopathic or the initial stage of polydactylous longitudinal erythronychia-associated systemic conditions. Polydactylous longitudinal erythronychia is most commonly reported in patients with Darier disease (keratosis follicularis); other associated conditions include acantholytic dyskeratotic epidermal nevus, acantholytic epidermolysis bullosa, acrokeratosis verruciformis of Hopf, amyloidosis, graft-versus-host disease, lichen planus, and pseudobulbar syndrome. Polydactylous longitudinal erythronychia has also been observed as an idiopathic finding. Biopsy of the nail matrix and nail bed may be necessary to establish the diagnosis of a longitudinal erythronychia-associated condition. Indeed, a biopsy should be seriously considered in patients aged more than 50 years who present with a monodactylous longitudinal red band to exclude squamous cell carcinoma. Treatment of longitudinal erythronychia depends on the etiology. For patients with longitudinal erythronychia-associated discomfort or severe nail splitting, a surgical excision may provide not only the underlying diagnosis of the nail dyschromia, but also relief of related symptoms.

Students' Classroom Engagement Produces Longitudinal Changes in Classroom Motivation

ERIC Educational Resources Information Center

Reeve, Johnmarshall; Lee, Woogul

2014-01-01

Changes in motivation anticipate changes in engagement, but the present study tested the reciprocal relation that changes in students' classroom engagement lead to corresponding longitudinal changes in their classroom motivation. Achievement scores and multiple measures of students' course-specific motivation (psychological need satisfaction,…

Longitudinal confinement and matching of an intense electron beam

NASA Astrophysics Data System (ADS)

Beaudoin, B.; Haber, I.; Kishek, R. A.; Bernal, S.; Koeth, T.; Sutter, D.; O'Shea, P. G.; Reiser, M.

2011-01-01

An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifth turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.

Longitudinally extensive transverse myelitis in neuromyelitis optica: a prospective study of 13 Caucasian patients and literature review.

PubMed

Bălaşa, Rodica; Maier, Smaranda; Bajko, Zoltan; Motataianu, Anca; Crişan, Alexandra; Bălaşa, Adrian

2015-12-01

Neuromyelitis optica (NMO) is a homogenous disease that can be diagnosed by an association of clinical, neuroimaging and serological aspects. We analysed our 4 years NMO series with longitudinally extensive transverse myelitis (LETM) during the disease course. We included consecutive adult Caucasian patients who were diagnosed with definite NMO, or cases of NMO-IgG seropositive LETM considered as limited forms of NMO. Patients included were negative for other diseases (autoimmune, infectious, etc.). We report the Expanded Disability Status Scale (EDSS), brain and spine MRI, CSF, NMO-IgG, treatment, motor and visual outcome. Thirteen cases fulfilled the inclusion criteria, and the mean follow-up period was 3.74 ± 1.8 years. The initial motor deficit was severe with the mean value of motor functional parameter of 4.46 ± 1 and improved at discharge to 2.53 ± 1.4 (p < 0.001). With treatment, the outcome after LETM attack was good in 10 patients, with a significant improvement of the EDSS mainly upon motor deficit, while visual function had a very slight amelioration. The CSF analysis was normal in 8 cases; spinal MRI showed evidence of LETM in all patients while brain MRI was normal in 7. NMO-IgG is a biomarker for NMO that is of diagnostic value in cases of isolated LETM. LETM has a better outcome than ON in NMO Caucasians. Spinal MRI is essential for NMO diagnosis in the presence of LETM and the absence of multiple brain MRI lesions. Maintenance immunosuppressive therapy reduces the frequency of attacks.

Longitudinal bracketed epiphysis of proximal phalanx of the great toe with congenital hallux varus managed simultaneously with monorail external fixator: a case report.

PubMed

Verma, Vineet; Batra, Amit; Singla, Rohit; Gogna, Paritosh; Magu, Narender; Gupta, Rakesh

2014-02-01

Longitudinal bracketed epiphysis (delta phalanx) is a rare congenital anomaly that affects phalanges in the hand more commonly than toes. We present a rare case of congenital hallux varus with longitudinal bracketed epiphysis of proximal phalanx with bifid distal phalanx of the great toe, which was managed with monorail type of external fixator. To the best of our knowledge, this is the first report of its successful implementation in simultaneous treatment of longitudinal bracketed epiphysis of the proximal phalanx of the great toe and hallux varus. Apart from adding to the literature a case of rare subtype of delta phalanx with hallux varus, the present study highlights the role of a reliable alternative in its management.

Revisiting the Dedifferentiation Hypothesis with Longitudinal Multi-Cohort Data

ERIC Educational Resources Information Center

de Frias, Cindy M.; Lovden, Martin; Lindenberger, Ulman; Nilsson, Lars-Goran

2007-01-01

The present longitudinal multi-cohort study examines whether interindividual variability in cognitive performance and change increases in old age, and whether associations among developments of different cognitive functions increase with adult age. Multivariate multiple-group latent growth modeling was applied to data from narrow cohorts separated…

Coding Response to a Case-Mix Measurement System Based on Multiple Diagnoses

PubMed Central

Preyra, Colin

2004-01-01

Objective To examine the hospital coding response to a payment model using a case-mix measurement system based on multiple diagnoses and the resulting impact on a hospital cost model. Data Sources Financial, clinical, and supplementary data for all Ontario short stay hospitals from years 1997 to 2002. Study Design Disaggregated trends in hospital case-mix growth are examined for five years following the adoption of an inpatient classification system making extensive use of combinations of secondary diagnoses. Hospital case mix is decomposed into base and complexity components. The longitudinal effects of coding variation on a standard hospital payment model are examined in terms of payment accuracy and impact on adjustment factors. Principal Findings Introduction of the refined case-mix system provided incentives for hospitals to increase reporting of secondary diagnoses and resulted in growth in highest complexity cases that were not matched by increased resource use over time. Despite a pronounced coding response on the part of hospitals, the increase in measured complexity and case mix did not reduce the unexplained variation in hospital unit cost nor did it reduce the reliance on the teaching adjustment factor, a potential proxy for case mix. The main implication was changes in the size and distribution of predicted hospital operating costs. Conclusions Jurisdictions introducing extensive refinements to standard diagnostic related group (DRG)-type payment systems should consider the effects of induced changes to hospital coding practices. Assessing model performance should include analysis of the robustness of classification systems to hospital-level variation in coding practices. Unanticipated coding effects imply that case-mix models hypothesized to perform well ex ante may not meet expectations ex post. PMID:15230940

Multiple Indicator Stationary Time Series Models.

ERIC Educational Resources Information Center

Sivo, Stephen A.

2001-01-01

Discusses the propriety and practical advantages of specifying multivariate time series models in the context of structural equation modeling for time series and longitudinal panel data. For time series data, the multiple indicator model specification improves on classical time series analysis. For panel data, the multiple indicator model…

Reoperative surgical stabilization of a painful nonunited rib fracture using bone grafting and a metal plate.

PubMed

Cho, Yang Hyun; Kim, Hyun Koo; Kang, Du-Young; Choi, Young Ho

2009-09-01

We report a case of a nonunited sixth rib in a patient with multiple rib fractures who underwent internal fixation using a wire and Judet strut 3 times. During the following 3 years, the patient continued to complain of pain and instability. At surgery, a pseudarthrosis between the ends of the sixth rib was excised. A longitudinal gutter crossing the fracture site was fashioned and splinted with an inlay block of cancellous bone grafted from the iliac crest; stabilization was accomplished with a reconstruction plate and screws. The following 2 years of follow-up demonstrated no instability or pain.

Evaluation of the role of Care Sport Connectors in connecting primary care, sport, and physical activity, and residents' participation in the Netherlands: study protocol for a longitudinal multiple case study design.

PubMed

Smit, E; Leenaars, K E F; Wagemakers, M A E; Molleman, G R M; Koelen, M A; van der Velden, J

2015-11-23

The number of people with one or more chronic diseases is increasing, but this trend could be reduced by promoting physical activity. Therefore, in 2012, the Dutch Ministry of Health, Welfare, and Sport introduced Care Sport Connectors (CSCs), to whom a broker role has been ascribed. The defined outcome of CSCs role is an increased number of residents participating in local sports facilities and being physically active in their own neighbourhood. To realize this, primary care and sports professionals need to collaborate, and local sports facilities and neighbourhoods need to offer accessible physical activities for people in the locality, including people with one or more chronic diseases or at increased risk of chronic disease(s). Adequate scientific research is needed to assess CSCs' impact on: 1) connecting primary care, sport, and physical activity and 2) increasing the number of residents who engage in physical activity to promote their health. To study the role and the impact of CSCs, a longitudinal multiple case study will be conducted, in nine municipalities spread over the Netherlands, from 2014 until 2017. A mixed methodology will be used to perform action research and process evaluation. Study I focuses on the expected alliances of CSCs and the preconditions that facilitate or hinder CSCs in the formation of these alliances. The study population will consist of intermediary target groups. A literature review, interviews, focus groups, and document analysis will be undertaken. Study II will concentrate on lifestyle program participants to identify health and physical activity behavior changes. For this purpose, interviews, literature studies, a Delphi study, fitness tests, and questionnaires will be used. Linking and integrating results gained by multiple methods, at different levels, will provide a validated assessment of CSCs' impact on connecting the primary care and sports sectors. This will reveal changes in residents' physical activity behavior, and also the circumstances under which this will happen. The assessment in combination with general lessons learned from the different case studies will make it possible to determine whether CSCs are able to fulfill the policy aspiration and whether it would be beneficial to extend this function. Nederlands Trialregister NTR4986 . Registered 14 December 2014.

A Comparison of Various MRA Methods Applied to Longitudinal Evaluation Studies in Vocational Education.

ERIC Educational Resources Information Center

Kapes, Jerome T.; And Others

Three models of multiple regression analysis (MRA): single equation, commonality analysis, and path analysis, were applied to longitudinal data from the Pennsylvania Vocational Development Study. Variables influencing weekly income of vocational education students one year after high school graduation were examined: grade point averages (grades…

Longitudinal Examination of Adaptive Behavior in Autism Spectrum Disorders: Influence of Executive Function

ERIC Educational Resources Information Center

Pugliese, Cara E.; Anthony, Laura Gutermuth; Strang, John F.; Dudley, Katerina; Wallace, Gregory L.; Naiman, Daniel Q.; Kenworthy, Lauren

2016-01-01

This study characterizes longitudinal change in adaptive behavior in 64 children and adolescents with autism spectrum disorder (ASD) without intellectual disability evaluated on multiple occasions, and examines whether prior estimate of executive function (EF) problems predicts future adaptive behavior scores. Compared to standardized estimates…

Longitudinal and Contextual Associations between Teacher-Student Relationships and Student Engagement: A Systematic Review

ERIC Educational Resources Information Center

Quin, Daniel

2017-01-01

This systematic review examined multiple indicators of adolescent students' engagement in school, and the indicators' associations with teacher-student relationships (TSRs). Seven psychology, education, and social sciences databases were systematically searched. From this search, 46 published studies (13 longitudinal) were included for detailed…

Data Integration Approaches to Longitudinal Growth Modeling

ERIC Educational Resources Information Center

Marcoulides, Katerina M.; Grimm, Kevin J.

2017-01-01

Synthesizing results from multiple studies is a daunting task during which researchers must tackle a variety of challenges. The task is even more demanding when studying developmental processes longitudinally and when different instruments are used to measure constructs. Data integration methodology is an emerging field that enables researchers to…

Congenital Malalignment of the Great Toenail.

PubMed

Fierro-Arias, Leonel; Morales-Martínez, André; Zazueta-López, Rosa María; Ramírez-Dovala, Silvia; Bonifaz, Alexandro; Ponce-Olivera, Rosa María

2015-01-01

Congenital malalignment of the great toenail (CMA) is a disorder of the anatomic orientation of the ungual apparatus, in which the longitudinal axis of the nail plate is not parallel with the axis of the distal phalanx but is deflected sideways. This disorder is understood to arise from multiple factors. Although many theories have been proposed about its origin, its pathogenesis is not fully known. Besides the cosmetic impact, this disorder causes such problems in the medium and long term as onychocryptosis and difficulty in motion. Some cases may regress spontaneously, although persistent cases may require a specialized surgical approach. Congenital malalignment of the great toenail is poorly understood and described medical condition that is often treated incorrectly; thus, reviewing the subject is important. A symptombased clinical classification system is proposed to guide diagnosis and treatment modality decisions.

An investigation of emotion dynamics in major depressive disorder patients and healthy persons using sparse longitudinal networks.

PubMed

de Vos, Stijn; Wardenaar, Klaas J; Bos, Elisabeth H; Wit, Ernst C; Bouwmans, Mara E J; de Jonge, Peter

2017-01-01

Differences in within-person emotion dynamics may be an important source of heterogeneity in depression. To investigate these dynamics, researchers have previously combined multilevel regression analyses with network representations. However, sparse network methods, specifically developed for longitudinal network analyses, have not been applied. Therefore, this study used this approach to investigate population-level and individual-level emotion dynamics in healthy and depressed persons and compared this method with the multilevel approach. Time-series data were collected in pair-matched healthy persons and major depressive disorder (MDD) patients (n = 54). Seven positive affect (PA) and seven negative affect (NA) items were administered electronically at 90 times (30 days; thrice per day). The population-level (healthy vs. MDD) and individual-level time series were analyzed using a sparse longitudinal network model based on vector autoregression. The population-level model was also estimated with a multilevel approach. Effects of different preprocessing steps were evaluated as well. The characteristics of the longitudinal networks were investigated to gain insight into the emotion dynamics. In the population-level networks, longitudinal network connectivity was strongest in the healthy group, with nodes showing more and stronger longitudinal associations with each other. Individually estimated networks varied strongly across individuals. Individual variations in network connectivity were unrelated to baseline characteristics (depression status, neuroticism, severity). A multilevel approach applied to the same data showed higher connectivity in the MDD group, which seemed partly related to the preprocessing approach. The sparse network approach can be useful for the estimation of networks with multiple nodes, where overparameterization is an issue, and for individual-level networks. However, its current inability to model random effects makes it less useful as a population-level approach in case of large heterogeneity. Different preprocessing strategies appeared to strongly influence the results, complicating inferences about network density.

Advancements in Nanomedicine for Multiple Myeloma.

PubMed

Detappe, Alexandre; Bustoros, Mark; Mouhieddine, Tarek H; Ghoroghchian, P Peter

2018-06-01

In the past decades, considerable progress has been made in our understanding and treatment of multiple myeloma. Several challenges remain including our abilities to longitudinally image tumor responses to treatment, to combine various therapeutic agents with different mechanisms of action but with overlapping toxicities, and to efficiently harness the power of the immune system to augment remission and/or to induce permanent cures. Nanomedicine may help to address many of these outstanding issues, affording novel diagnostic capabilities and offering disruptive technologies that promise to revolutionize treatment. Here, we review recent developments and the future of nanomedicine for multiple myeloma, highlighting new considerations in nanoparticle designs that may help to augment active targeting, to facilitate longitudinal imaging, and to improve drug delivery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Longitudinal development of muons in large air showers studies from the arrival time distributions measured at 900m above sea level

NASA Technical Reports Server (NTRS)

Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.

1985-01-01

The arrival time distributions of muons with energies above 1.0GeV and 0.5GeV have been measured in the Akeno air-shower array to study the longitudinal development of muons in air showers with primary energies in the range 10 to the 17th power to 10 to the 18th power ev. The average rise times of muons with energies above 1.0GeV at large core distances are consistent with those expected from very high multiplicity models and, on the contrary, with those expected from the low multiplicity models at small core distances. This implies that the longitudinal development at atmospheric depth smaller than 500 cm square is very fast and that at larger atmospheric depths is rather slow.

Bayesian Modeling of NMR Data: Quantifying Longitudinal Relaxation in Vivo, and in Vitro with a Tissue-Water-Relaxation Mimic (Crosslinked Bovine Serum Albumin).

PubMed

Meinerz, Kelsey; Beeman, Scott C; Duan, Chong; Bretthorst, G Larry; Garbow, Joel R; Ackerman, Joseph J H

2018-01-01

Recently, a number of MRI protocols have been reported that seek to exploit the effect of dissolved oxygen (O 2 , paramagnetic) on the longitudinal 1 H relaxation of tissue water, thus providing image contrast related to tissue oxygen content. However, tissue water relaxation is dependent on a number of mechanisms, and this raises the issue of how best to model the relaxation data. This problem, the model selection problem, occurs in many branches of science and is optimally addressed by Bayesian probability theory. High signal-to-noise, densely sampled, longitudinal 1 H relaxation data were acquired from rat brain in vivo and from a cross-linked bovine serum albumin (xBSA) phantom, a sample that recapitulates the relaxation characteristics of tissue water in vivo . Bayesian-based model selection was applied to a cohort of five competing relaxation models: (i) monoexponential, (ii) stretched-exponential, (iii) biexponential, (iv) Gaussian (normal) R 1 -distribution, and (v) gamma R 1 -distribution. Bayesian joint analysis of multiple replicate datasets revealed that water relaxation of both the xBSA phantom and in vivo rat brain was best described by a biexponential model, while xBSA relaxation datasets truncated to remove evidence of the fast relaxation component were best modeled as a stretched exponential. In all cases, estimated model parameters were compared to the commonly used monoexponential model. Reducing the sampling density of the relaxation data and adding Gaussian-distributed noise served to simulate cases in which the data are acquisition-time or signal-to-noise restricted, respectively. As expected, reducing either the number of data points or the signal-to-noise increases the uncertainty in estimated parameters and, ultimately, reduces support for more complex relaxation models.

A Multi-Dimensional Functional Principal Components Analysis of EEG Data

PubMed Central

Hasenstab, Kyle; Scheffler, Aaron; Telesca, Donatello; Sugar, Catherine A.; Jeste, Shafali; DiStefano, Charlotte; Şentürk, Damla

2017-01-01

Summary The electroencephalography (EEG) data created in event-related potential (ERP) experiments have a complex high-dimensional structure. Each stimulus presentation, or trial, generates an ERP waveform which is an instance of functional data. The experiments are made up of sequences of multiple trials, resulting in longitudinal functional data and moreover, responses are recorded at multiple electrodes on the scalp, adding an electrode dimension. Traditional EEG analyses involve multiple simplifications of this structure to increase the signal-to-noise ratio, effectively collapsing the functional and longitudinal components by identifying key features of the ERPs and averaging them across trials. Motivated by an implicit learning paradigm used in autism research in which the functional, longitudinal and electrode components all have critical interpretations, we propose a multidimensional functional principal components analysis (MD-FPCA) technique which does not collapse any of the dimensions of the ERP data. The proposed decomposition is based on separation of the total variation into subject and subunit level variation which are further decomposed in a two-stage functional principal components analysis. The proposed methodology is shown to be useful for modeling longitudinal trends in the ERP functions, leading to novel insights into the learning patterns of children with Autism Spectrum Disorder (ASD) and their typically developing peers as well as comparisons between the two groups. Finite sample properties of MD-FPCA are further studied via extensive simulations. PMID:28072468

A multi-dimensional functional principal components analysis of EEG data.

PubMed

Hasenstab, Kyle; Scheffler, Aaron; Telesca, Donatello; Sugar, Catherine A; Jeste, Shafali; DiStefano, Charlotte; Şentürk, Damla

2017-09-01

The electroencephalography (EEG) data created in event-related potential (ERP) experiments have a complex high-dimensional structure. Each stimulus presentation, or trial, generates an ERP waveform which is an instance of functional data. The experiments are made up of sequences of multiple trials, resulting in longitudinal functional data and moreover, responses are recorded at multiple electrodes on the scalp, adding an electrode dimension. Traditional EEG analyses involve multiple simplifications of this structure to increase the signal-to-noise ratio, effectively collapsing the functional and longitudinal components by identifying key features of the ERPs and averaging them across trials. Motivated by an implicit learning paradigm used in autism research in which the functional, longitudinal, and electrode components all have critical interpretations, we propose a multidimensional functional principal components analysis (MD-FPCA) technique which does not collapse any of the dimensions of the ERP data. The proposed decomposition is based on separation of the total variation into subject and subunit level variation which are further decomposed in a two-stage functional principal components analysis. The proposed methodology is shown to be useful for modeling longitudinal trends in the ERP functions, leading to novel insights into the learning patterns of children with Autism Spectrum Disorder (ASD) and their typically developing peers as well as comparisons between the two groups. Finite sample properties of MD-FPCA are further studied via extensive simulations. © 2017, The International Biometric Society.

High speed internal permanent magnet machine and method of manufacturing the same

DOEpatents

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-09-13

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple permanent magnets for generating a magnetic field, which interacts with the stator magnetic field to produce torque. The permanent magnets are disposed between the stacks. The rotor assembly also includes multiple bottom wedges disposed on the bottom structures of the shaft and configured to hold the multiple stacks and the multiple permanent magnets.

Generation of double giant pulses in actively Q-switched lasers

NASA Astrophysics Data System (ADS)

Korobeynikova, A. P.; Shaikin, I. A.; Shaykin, A. A.; Koryukin, I. V.; Khazanov, E. A.

2018-04-01

Generation of a second giant pulse in a longitudinal mode neighbouring to the longitudinal mode possessing minimal losses is theoretically and experimentally studied in actively Q-switched lasers. A mathematical model is suggested for explaining the giant pulse generation in a laser with multiple longitudinal modes. The model makes allowance for not only a standing, but also a running wave for each cavity mode. Results of numerical simulation and data of experiments with a Nd : YLF laser explain the effect of second giant pulse generation in a neighbouring longitudinal mode. After a giant pulse in the mode with minimal losses is generated, the threshold for the neighbouring longitudinal mode is still exceeded due to the effect of burning holes in the population inversion spatial distribution.

Investigating Stage-Sequential Growth Mixture Models with Multiphase Longitudinal Data

ERIC Educational Resources Information Center

Kim, Su-Young; Kim, Jee-Seon

2012-01-01

This article investigates three types of stage-sequential growth mixture models in the structural equation modeling framework for the analysis of multiple-phase longitudinal data. These models can be important tools for situations in which a single-phase growth mixture model produces distorted results and can allow researchers to better understand…

Automatic Rejection Of Multimode Laser Pulses

NASA Technical Reports Server (NTRS)

Tratt, David M.; Menzies, Robert T.; Esproles, Carlos

1991-01-01

Characteristic modulation detected, enabling rejection of multimode signals. Monitoring circuit senses multiple longitudinal mode oscillation of transversely excited, atmospheric-pressure (TEA) CO2 laser. Facility developed for inclusion into coherent detection laser radar (LIDAR) system. However, circuit described of use in any experiment where desireable to record data only when laser operates in single longitudinal mode.

Assessing Change in Latent Skills across Time with Longitudinal Cognitive Diagnosis Modeling: An Evaluation of Model Performance

ERIC Educational Resources Information Center

Kaya, Yasemin; Leite, Walter L.

2017-01-01

Cognitive diagnosis models are diagnostic models used to classify respondents into homogenous groups based on multiple categorical latent variables representing the measured cognitive attributes. This study aims to present longitudinal models for cognitive diagnosis modeling, which can be applied to repeated measurements in order to monitor…

Early Childhood Predictors of the Social Competence of Adults with Autism

ERIC Educational Resources Information Center

Gillespie-Lynch, Kristen; Sepeta, Leigh; Wang, Yueyan; Marshall, Stephanie; Gomez, Lovella; Sigman, Marian; Hutman, Ted

2012-01-01

Longitudinal research into adult outcomes in autism remains limited. Unlike previous longitudinal examinations of adult outcome in autism, the twenty participants in this study were evaluated across multiple assessments between early childhood (M = 3.9 years) and adulthood (M = 26.6 years). In early childhood, responsiveness to joint attention…

The Importance of Additive Reasoning in Children's Mathematical Achievement: A Longitudinal Study

ERIC Educational Resources Information Center

Ching, Boby Ho-Hong; Nunes, Terezinha

2017-01-01

This longitudinal study examines the relative importance of counting ability, additive reasoning, and working memory in children's mathematical achievement (calculation and story problem solving). In Hong Kong, 115 Chinese children aged 6 years old participated in 2 waves of assessments (T1 = first grade and T2 = second grade). Multiple regression…

Brief Report: A Growth Mixture Model of Occupational Aspirations of Individuals with High-Incidence Disabilities

ERIC Educational Resources Information Center

Lee, In Heok; Rojewski, Jay W.

2013-01-01

A previous longitudinal study of the occupational aspirations of individuals with high-incidence disabilities revealed multiple longitudinal patterns for individuals with learning disabilities or emotional-behavioral disorders. Growth mixture modeling was used to determine whether individuals in these two high-incidence disabilities groups (N =…

Quantification of right ventricular volumes and function by real time three-dimensional echocardiographic longitudinal axial plane method: validation in the clinical setting.

PubMed

Endo, Yuka; Maddukuri, Prasad V; Vieira, Marcelo L C; Pandian, Natesa G; Patel, Ayan R

2006-11-01

Measurement of right ventricular (RV) volumes and right ventricular ejection fraction (RVEF) by three-dimensional echocardiographic (3DE) short-axis disc summation method has been validated in multiple studies. However, in some patients, short-axis images are of insufficient quality for accurate tracing of the RV endocardial border. This study examined the accuracy of long-axis analysis in multiple planes (longitudinal axial plane method) for assessment of RV volumes and RVEF. 3DE images were analyzed in 40 subjects with a broad range of RV function. RV end-diastolic (RVEDV) and end-systolic volumes (RVESV) and RVEF were calculated by both short-axis disc summation method and longitudinal axial plane method. Excellent correlation was obtained between the two methods for RVEDV, RVESV, and RVEF (r = 0.99, 0.99, 0.94, respectively; P < 0.0001 for all comparisons). 3DE longitudinal-axis analysis is a promising technique for the evaluation of RV function, and may provide an alternative method of assessment in patients with suboptimal short-axis images.

The effects of cumulative risks and promotive factors on urban adolescent alcohol and other drug use: a longitudinal study of resiliency.

PubMed

Ostaszewski, Krzysztof; Zimmerman, Marc A

2006-12-01

Resiliency theory provides a conceptual framework for studying why some youth exposed to risk factors do not develop the negative behaviors they predict. The purpose of this study was to test compensatory and protective models of resiliency in a longitudinal sample of urban adolescents (80% African American). The data were from Years 1 (9th grade) and 4 (12th grade). The study examined effects of cumulative risk and promotive factors on adolescent polydrug use including alcohol, tobacco and marijuana. Cumulative measures of risk/promotive factors represented individual characteristics, peer influence, and parental/familial influences. After controlling for demographics, results of multiple regression of polydrug use support the compensatory model of resiliency both cross-sectionally and longitudinally. Promotive factors were also found to have compensatory effects on change in adolescent polydrug use. The protective model of resiliency evidenced cross-sectionally was not supported in longitudinal analysis. The findings support resiliency theory and the use of cumulative risk/promotive measures in resiliency research. Implications focused on utilizing multiple assets and resources in prevention programming are discussed.

High-frequency, silicon-based ultrasonic nozzles using multiple Fourier horns.

PubMed

Tsai, Shirley C; Song, Yu L; Tseng, Terry K; Chou, Yuan F; Chen, Wei J; Tsai, Chen S

2004-03-01

This paper presents the design, simulation, and characterization of microfabricated 0.5 MHz, silicon-based, ultrasonic nozzles. Each nozzle is made of a piezoelectric drive section and a silicon resonator consisting of multiple Fourier horns, each with half wavelength design and twice amplitude magnification. Results of finite element three-dimensional (3-D) simulation using a commercial program predicted existence of one resonant frequency of pure longitudinal vibration. Both impedance analysis and measurement of longitudinal vibration confirmed the simulation results with one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude at the nozzle tip increases as the number of Fourier horns (n) increases in good agreement with the theoretical values of 2(n). Using this design, very high vibration amplitude gain at the nozzle tip can be achieved with no reduction in the tip cross-sectional area for contact of liquid to be atomized. Therefore, the required electric drive power should be drastically reduced, decreasing the likelihood of transducer failure in ultrasonic atomization.

Using Faculty Evaluation to Improve Teaching Quality: A Longitudinal Case Study of Higher Education in Southeast Asia

ERIC Educational Resources Information Center

Hallinger, Philip

2010-01-01

This paper presents a case study of implementation of a new system of faculty teaching evaluation at a graduate school of business in Thailand. The research employed a non-experimental, longitudinal case study design in the analysis of student course evaluation data gathered over a period of 21 terms during a seven-year period. The report…

Teacher-student relationship quality and academic achievement in elementary school: A longitudinal examination of gender differences.

PubMed

Hajovsky, Daniel B; Mason, Benjamin A; McCune, Luke A

2017-08-01

Multiple group longitudinal cross-lagged panel models were implemented to understand the directional influences between teacher-student closeness and conflict and measured math and reading achievement across elementary grades and gender groups using the National Institute of Child Health and Human Development longitudinal sample (N=1133). Specifically, after testing multiple group longitudinal measurement invariance to ensure consistent measurement across genders and time, and tests of equivalence of the latent parameters, we were interested in whether longitudinal changes in teacher-rated closeness and conflict explained longitudinal changes in achievement, and vice versa, and whether those longitudinal influences varied by gender. Latent teacher-student closeness decreased for both genders over time (Cohen's d=-0.15 to -0.32), but latent conflict increased for males (Cohen's d=0.16). There was also increased heterogeneity in teacher-student relationship quality for males relative to females. Math and reading achievement had medium reciprocal effects (β=0.12 to 0.23), and previous math achievement had small to medium effects on subsequent teacher-student closeness (β=0.08 to 0.11) and conflict (β=-0.07 to -0.09). Teacher-student conflict and closeness did not influence subsequent levels of math or reading achievement once previous levels were controlled. Further, these influences were consistent across gender groups despite latent differences in teacher-student closeness and conflict with teachers reporting closer relationships with female students and more conflictual relationships with male students. Copyright © 2017 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Multiple Imputation of Cognitive Performance as a Repeatedly Measured Outcome

PubMed Central

Rawlings, Andreea M.; Sang, Yingying; Sharrett, A. Richey; Coresh, Josef; Griswold, Michael; Kucharska-Newton, Anna M.; Palta, Priya; Wruck, Lisa M.; Gross, Alden L.; Deal, Jennifer A.; Power, Melinda C.; Bandeen-Roche, Karen

2016-01-01

Background Longitudinal studies of cognitive performance are sensitive to dropout, as participants experiencing cognitive deficits are less likely to attend study visits, which may bias estimated associations between exposures of interest and cognitive decline. Multiple imputation is a powerful tool for handling missing data, however its use for missing cognitive outcome measures in longitudinal analyses remains limited. Methods We use multiple imputation by chained equations (MICE) to impute cognitive performance scores of participants who did not attend the 2011-2013 exam of the Atherosclerosis Risk in Communities Study. We examined the validity of imputed scores using observed and simulated data under varying assumptions. We examined differences in the estimated association between diabetes at baseline and 20-year cognitive decline with and without imputed values. Lastly, we discuss how different analytic methods (mixed models and models fit using generalized estimate equations) and choice of for whom to impute result in different estimands. Results Validation using observed data showed MICE produced unbiased imputations. Simulations showed a substantial reduction in the bias of the 20-year association between diabetes and cognitive decline comparing MICE (3-4% bias) to analyses of available data only (16-23% bias) in a construct where missingness was strongly informative but realistic. Associations between diabetes and 20-year cognitive decline were substantially stronger with MICE than in available-case analyses. Conclusions Our study suggests when informative data are available for non-examined participants, MICE can be an effective tool for imputing cognitive performance and improving assessment of cognitive decline, though careful thought should be given to target imputation population and analytic model chosen, as they may yield different estimands. PMID:27619926

Hypothesis testing in functional linear regression models with Neyman's truncation and wavelet thresholding for longitudinal data.

PubMed

Yang, Xiaowei; Nie, Kun

2008-03-15

Longitudinal data sets in biomedical research often consist of large numbers of repeated measures. In many cases, the trajectories do not look globally linear or polynomial, making it difficult to summarize the data or test hypotheses using standard longitudinal data analysis based on various linear models. An alternative approach is to apply the approaches of functional data analysis, which directly target the continuous nonlinear curves underlying discretely sampled repeated measures. For the purposes of data exploration, many functional data analysis strategies have been developed based on various schemes of smoothing, but fewer options are available for making causal inferences regarding predictor-outcome relationships, a common task seen in hypothesis-driven medical studies. To compare groups of curves, two testing strategies with good power have been proposed for high-dimensional analysis of variance: the Fourier-based adaptive Neyman test and the wavelet-based thresholding test. Using a smoking cessation clinical trial data set, this paper demonstrates how to extend the strategies for hypothesis testing into the framework of functional linear regression models (FLRMs) with continuous functional responses and categorical or continuous scalar predictors. The analysis procedure consists of three steps: first, apply the Fourier or wavelet transform to the original repeated measures; then fit a multivariate linear model in the transformed domain; and finally, test the regression coefficients using either adaptive Neyman or thresholding statistics. Since a FLRM can be viewed as a natural extension of the traditional multiple linear regression model, the development of this model and computational tools should enhance the capacity of medical statistics for longitudinal data.

Multiple Trajectories of Successful Aging of Older and Younger Cohorts

ERIC Educational Resources Information Center

Hsu, Hui-Chuan; Jones, Bobby L.

2012-01-01

Purpose: The purpose of this study was to apply group-based trajectory analysis to identify multiple successful aging trajectories by multiple indicators and to examine the factors related to successful aging among the elderly population in Taiwan. Design and Methods: Nation-representative longitudinal data collected from 1993 to 2007 and…

A mixed-effects regression model for longitudinal multivariate ordinal data.

PubMed

Liu, Li C; Hedeker, Donald

2006-03-01

A mixed-effects item response theory model that allows for three-level multivariate ordinal outcomes and accommodates multiple random subject effects is proposed for analysis of multivariate ordinal outcomes in longitudinal studies. This model allows for the estimation of different item factor loadings (item discrimination parameters) for the multiple outcomes. The covariates in the model do not have to follow the proportional odds assumption and can be at any level. Assuming either a probit or logistic response function, maximum marginal likelihood estimation is proposed utilizing multidimensional Gauss-Hermite quadrature for integration of the random effects. An iterative Fisher scoring solution, which provides standard errors for all model parameters, is used. An analysis of a longitudinal substance use data set, where four items of substance use behavior (cigarette use, alcohol use, marijuana use, and getting drunk or high) are repeatedly measured over time, is used to illustrate application of the proposed model.

Material mechanical characterization method for multiple strains and strain rates

DOEpatents

Erdmand, III, Donald L.; Kunc, Vlastimil; Simunovic, Srdjan; Wang, Yanli

2016-01-19

A specimen for measuring a material under multiple strains and strain rates. The specimen including a body having first and second ends and a gage region disposed between the first and second ends, wherein the body has a central, longitudinal axis passing through the first and second ends. The gage region includes a first gage section and a second gage section, wherein the first gage section defines a first cross-sectional area that is defined by a first plane that extends through the first gage section and is perpendicular to the central, longitudinal axis. The second gage section defines a second cross-sectional area that is defined by a second plane that extends through the second gage section and is perpendicular to the central, longitudinal axis and wherein the first cross-sectional area is different in size than the second cross-sectional area.

Adolescent Victimization and Early-Adult Psychopathology: Approaching Causal Inference Using a Longitudinal Twin Study to Rule Out Noncausal Explanations

PubMed Central

Schaefer, Jonathan D.; Moffitt, Terrie E.; Arseneault, Louise; Danese, Andrea; Fisher, Helen L.; Houts, Renate; Sheridan, Margaret A.; Wertz, Jasmin; Caspi, Avshalom

2017-01-01

Adolescence is the peak age for both victimization and mental disorder onset. Previous research has reported associations between victimization exposure and many psychiatric conditions. However, causality remains controversial. Within the Environmental Risk Longitudinal Twin Study, we tested whether seven types of adolescent victimization increased risk of multiple psychiatric conditions and approached causal inference by systematically ruling out noncausal explanations. Longitudinal within-individual analyses showed that victimization was followed by increased mental health problems over a childhood baseline of emotional/behavioral problems. Discordant-twin analyses showed that victimization increased risk of mental health problems independent of family background and genetic risk. Both childhood and adolescent victimization made unique contributions to risk. Victimization predicted heightened generalized liability (the “p factor”) to multiple psychiatric spectra, including internalizing, externalizing, and thought disorders. Results recommend violence reduction and identification and treatment of adolescent victims to reduce psychiatric burden. PMID:29805917

Longitudinal Prediction of Disruptive Behavior Disorders in Adolescent Males from Multiple Risk Domains

PubMed Central

Trentacosta, Christopher J.; Hyde, Luke W.; Goodlett, Benjamin D.; Shaw, Daniel S.

2012-01-01

The disruptive behavior disorders are among the most prevalent youth psychiatric disorders, and they predict numerous problematic outcomes in adulthood. This study examined multiple domains of risk during early childhood and early adolescence as longitudinal predictors of disruptive behavior disorder diagnoses among adolescent males. Early adolescent risks in the domains of sociodemographic factors, the caregiving context, and youth attributes were examined as mediators of associations between early childhood risks and disruptive behavior disorder diagnoses. Participants were 309 males from a longitudinal study of low-income mothers and their sons. Caregiving and youth risk during early adolescence each predicted the likelihood of receiving a disruptive behavior disorder diagnosis. Furthermore, sociodemographic and caregiving risk during early childhood were indirectly associated with disruptive behavior disorder diagnoses via their association with early adolescent risk. The findings suggest that preventive interventions targeting risk across domains may reduce the prevalence of disruptive behavior disorders. PMID:23239427

Widely distributed SEP events and pseudostreamers

NASA Astrophysics Data System (ADS)

Panasenco, O.; Panasenco, A.; Velli, M.

2017-12-01

Our analysis of the pseudostreamer magnetic topology reveals new interesting implications for understanding SEP acceleration in CMEs. The possible reasons for the wide distribution of some SEP events can be the presence of pseudostreamers in the vicinity of the SEP source region which creates conditions for the existence of strong longitudinal spread of energetic particles as well as an anomalous longitudinal solar wind magnetic field component. We reconstructed the 3D magnetic configurations of pseudostreamers with a potential field source surface (PFSS) model, which uses as a lower boundary condition the magnetic field derived from an evolving surface-flux transport model. In order to estimate the possible magnetic connections between the spacecraft and the SEP source region, we used the Parker spiral, ENLIL and PFSS models. We found that in cases of the wide SEP distributions a specific configuration of magnetic field appears to exist at low solar latitudes all the way around the sun, we named this phenomenon a pseudostreamers belt. It appears that the presence of the well developed pseudostreamer or, rather multiple pseudostreamers, organized into the pseudostreamer belt can be considered as a very favorable condition for wide SEP events.

Association of infectious mononucleosis with multiple sclerosis. A population-based study.

PubMed

Ramagopalan, Sreeram V; Valdar, William; Dyment, David A; DeLuca, Gabriele C; Yee, Irene M; Giovannoni, Gavin; Ebers, George C; Sadovnick, A Dessa

2009-01-01

Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. Several studies have attempted to correlate exposure to viral illness with the subsequent development of MS. Here in a population-based Canadian cohort, we investigate the relationship between prior clinical infection or vaccination and the risk of MS. Using the longitudinal Canadian database, 14,362 MS index cases and 7,671 spouse controls were asked about history of measles, mumps, rubella, varicella and infectious mononucleosis as well as details about vaccination with measles, mumps, rubella, hepatitis B and influenza vaccines. Comparisons were made between cases and spouse controls. Spouse controls and stratification by sex appear to correct for ascertainment bias because with a single exception we found no significant differences between cases and controls for all viral exposures and vaccinations. However, 699 cases and 165 controls reported a history of infectious mononucleosis (p < 0.001, corrected odds ratio 2.06, 95% confidence interval 1.71-2.48). Females were more aware of disease history than males (p < 0.001). The data further confirms a reporting distortion between males and females. Historically reported measles, mumps, rubella, varicella and vaccination for hepatitis B, influenza, measles, mumps and rubella are not associated with increased risk of MS later in life. A clinical history of infectious mononucleosis is conspicuously associated with increased MS susceptibility. These findings support studies implicating Epstein-Barr virus in MS disease susceptibility, but a co-association between MS susceptibility and clinically apparent infectious mononucleosis cannot be excluded.

Association of Genetic Risk for Schizophrenia With Nonparticipation Over Time in a Population-Based Cohort Study.

PubMed

Martin, Joanna; Tilling, Kate; Hubbard, Leon; Stergiakouli, Evie; Thapar, Anita; Davey Smith, George; O'Donovan, Michael C; Zammit, Stanley

2016-06-15

Progress has recently been made in understanding the genetic basis of schizophrenia and other psychiatric disorders. Longitudinal studies are complicated by participant dropout, which could be related to the presence of psychiatric problems and associated genetic risk. We tested whether common genetic variants implicated in schizophrenia were associated with study nonparticipation among 7,867 children and 7,850 mothers from the Avon Longitudinal Study of Parents and Children (ALSPAC; 1991-2007), a longitudinal population cohort study. Higher polygenic risk scores for schizophrenia were consistently associated with noncompletion of questionnaires by study mothers and children and nonattendance at data collection throughout childhood and adolescence (ages 1-15 years). These associations persisted after adjustment for other potential correlates of nonparticipation. Results suggest that persons at higher genetic risk for schizophrenia are likely to be underrepresented in cohort studies, which will underestimate risk of this and related psychiatric, cognitive, and behavioral phenotypes in the population. Statistical power to detect associations with these phenotypes will be reduced, while analyses of schizophrenia-related phenotypes as outcomes may be biased by the nonrandom missingness of these phenotypes, even if multiple imputation is used. Similarly, in complete-case analyses, collider bias may affect associations between genetic risk and other factors associated with missingness. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

Ratchet Transport of Chiral Particles Caused by the Transversal Asymmetry: Current Reversals and Particle Separation

NASA Astrophysics Data System (ADS)

Liu, Jian-li; Lu, Shi-cai; Ai, Bao-quan

2018-06-01

Due to the chirality of active particles, the transversal asymmetry can induce the the longitudinal directed transport. The transport of chiral active particles in a periodic channel is investigated in the presence of two types of the transversal asymmetry, the transverse force and the transverse rigid half-circle obstacles. For all cases, the counterclockwise and clockwise particles move to the opposite directions. For the case of the only transverse force, the chiral active particles can reverse their directions when increasing the transverse force. When the transverse rigid half-circle obstacles are introduced, the transport behavior of particles becomes more complex and multiple current reversals occur. The direction of the transport is determined by the competition between two types of the transversal asymmetry. For a given chirality, by suitably tailoring parameters, particles with different self-propulsion speed can move in different directions and can be separated.

Harmonic plasma waves excitation and structure evolution of intense ion beams in background plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Zhang-Hu, E-mail: zhanghu@dlut.edu.cn; Wang, You-Nian

2016-08-15

The long-term dynamic evolutions of intense ion beams in plasmas have been investigated with two-dimensional electromagnetic particle simulations, taking into account the effect of the two-stream instability between beam ions and plasma electrons. Depending on the initial beam radial density profile and velocity distribution, ring structures may be formed in the beam edge regions. At the later stage of beam-plasma interactions, the ion beams are strongly modulated by the two-stream instability and multiple density spikes are formed in the longitudinal direction. The formation of these density spikes is shown to result from the excitation of harmonic plasma waves when themore » instability gets saturated. Comparisons between the beam cases with initial flat-top and Gaussian radial density profiles are made, and a higher instability growth rate is observed for the flat-top profile case.« less

No More "Magic Aprons": Longitudinal Assessment and Continuous Improvement of Customer Service at the University of North Dakota Libraries

ERIC Educational Resources Information Center

Clark, Karlene T.; Walker, Stephanie R.

2017-01-01

The University of North Dakota (UND) Libraries have developed a multi-award winning Customer Service Program (CSP) involving longitudinal assessment and continuous improvement. The CSP consists of iterative training modules; constant reinforcement of Customer Service Principles with multiple communication strategies and tools, and incentives that…

The Development of Second Language Writing Complexity in Groups and Individuals: A Longitudinal Learner Corpus Study

ERIC Educational Resources Information Center

Vyatkina, Nina

2012-01-01

This study explores the development of multiple dimensions of linguistic complexity in the writing of beginning learners of German both as a group and as individuals. The data come from an annotated, longitudinal learner corpus. The development of lexicogrammatical complexity is explored at 2 intersections: (a) between cross-sectional trendlines…

NLS Handbook, 2005. National Longitudinal Surveys

ERIC Educational Resources Information Center

Bureau of Labor Statistics, 2006

2006-01-01

The National Longitudinal Surveys (NLS), sponsored by the U.S. Bureau of Labor Statistics (BLS), are a set of surveys designed to gather information at multiple points in time on the labor market experiences of groups of men and women. Each of the cohorts has been selected to represent all people living in the United States at the initial…

Longitudinal Indicators of the Social Context of Families: Beyond the Snapshot

ERIC Educational Resources Information Center

Moore, Kristin Anderson; Vandivere, Sharon

2007-01-01

Longitudinal indicators are measures of an individual or family behavior, interaction, attitude, or value that are assessed consistently or comparably across multiple points in time and cumulated over time. Examples include the percentage of time a family lived in poverty or the proportion of childhood a person lived in a single-parent family.…

Methods and Measures: Growth Mixture Modeling--A Method for Identifying Differences in Longitudinal Change among Unobserved Groups

ERIC Educational Resources Information Center

Ram, Nilam; Grimm, Kevin J.

2009-01-01

Growth mixture modeling (GMM) is a method for identifying multiple unobserved sub-populations, describing longitudinal change within each unobserved sub-population, and examining differences in change among unobserved sub-populations. We provide a practical primer that may be useful for researchers beginning to incorporate GMM analysis into their…

Etiology of Pervasive versus Situational Antisocial Behaviors: A Multi-informant Longitudinal Cohort Study

ERIC Educational Resources Information Center

Wertz, Jasmin; Zavos, Helena M. S.; Matthews, Timothy; Gray, Rebecca; Best-Lane, Janis; Pariante, Carmine M.; Moffitt, Terrie E.; Arseneault, Louise

2016-01-01

The aim of this study was to disentangle pervasive from situational antisocial behaviors using multiple informants, and to investigate their genetic and environmental etiologies in preadolescence and across time. Antisocial behaviors were assessed in 2,232 twins from the Environmental Risk (E-Risk) Longitudinal Twin Study at ages 5 and 12.…

Individual Differences in Pronoun Reversal: Evidence from Two Longitudinal Case Studies

ERIC Educational Resources Information Center

Evans, Karen E.; Demuth, Katherine

2012-01-01

Pronoun reversal, the use of "you" for self-reference and "I" for an addressee, has often been associated with Autism Spectrum Disorder (ASD) and impaired language. However, recent case studies have shown the phenomenon also to occur in typically developing and even precocious talkers. This study examines longitudinal corpus data from two…

Removed from the List: A Comparative Longitudinal Case Study of a Reconstitution-Eligible School.

ERIC Educational Resources Information Center

Mac Iver, Douglas J.; Ruby, Allen; Balfanz, Robert; Byrnes, Vaughan

2002-01-01

Longitudinal case study of reform efforts centering on the Talent Development Middle School model at low-performing, high-poverty middle school in Philadelphia. Finds that student gains in mathematics, science, and reading achievement at subject school exceeded that of students in comparable school. (Contains 19 references.) (PKP)

HRD: Past, Present and Future. Symposium.

ERIC Educational Resources Information Center

2002

This document contains three papers from a symposium on the past, present, and future of human resource development (HRD). "Revisiting the New Deal: A Longitudinal Case Study" (Judy Pate, Graeme Martin, Jim McGoldrick) draws upon data from a longitudinal case study of the links between job security and HRD to examine the new…

[Maternal and perinatal risk factors for neonatal morbidity: a narrative literature review].

PubMed

Hernández Núñez, Jónathan; Valdés Yong, Magel; Suñol Vázquez, Yoanca de la Caridad; López Quintana, Marelene de la Caridad

2015-07-14

Newborn diseases increase neonatal mortality rates, so a literature review was conducted to establish the risk factors related to maternal and peripartum morbidity affecting the newborn. We searched the following electronic databases: Cumed, EBSCO, LILACS, IBECS and PubMed/MEDLINE. We used specific terms and Boolean operators in Spanish, Portuguese and English. We included longitudinal and cross-sectional descriptive studies, as well as case-control and cohort studies, systematic reviews and meta-analysis, spanning from 2010 to 2015 that responded the topic of interest. The included studies show that multiple maternal and perinatal conditions are risk factors for significant increase of neonatal morbidity, which are described in this narrative review.

Multiple Dimensions of Teacher Identity Development from Pre-Service to Early Years of Teaching: A Longitudinal Study

ERIC Educational Resources Information Center

Hong, Ji; Greene, Barbara; Lowery, Jennifer

2017-01-01

Based on dialogical self theory framework that highlights three dimensions of identity construction (multiplicity vs. unity; social vs. individual; discontinuity vs. continuity), this study explored multiple aspects of teacher identity development over time, in relation to the unity of self, the way the social environment is negotiated, and the…

Multiple Threats: The Co-Occurrence of Teen Health Risk Behaviors.

ERIC Educational Resources Information Center

Lindberg, Laura Duberstein; Boggess, Scott; Williams, Sean

This document presents a portrait of multiple risk-taking among teens. Using recent data from the National Longitudinal Study of Adolescent Health (Add Health) and the 1995 National Survey of Adolescent Males, the report describes the extent to which teens engage in multiple health risk behaviors and contrast it with the extent to which teens…

Multivariate test power approximations for balanced linear mixed models in studies with missing data.

PubMed

Ringham, Brandy M; Kreidler, Sarah M; Muller, Keith E; Glueck, Deborah H

2016-07-30

Multilevel and longitudinal studies are frequently subject to missing data. For example, biomarker studies for oral cancer may involve multiple assays for each participant. Assays may fail, resulting in missing data values that can be assumed to be missing completely at random. Catellier and Muller proposed a data analytic technique to account for data missing at random in multilevel and longitudinal studies. They suggested modifying the degrees of freedom for both the Hotelling-Lawley trace F statistic and its null case reference distribution. We propose parallel adjustments to approximate power for this multivariate test in studies with missing data. The power approximations use a modified non-central F statistic, which is a function of (i) the expected number of complete cases, (ii) the expected number of non-missing pairs of responses, or (iii) the trimmed sample size, which is the planned sample size reduced by the anticipated proportion of missing data. The accuracy of the method is assessed by comparing the theoretical results to the Monte Carlo simulated power for the Catellier and Muller multivariate test. Over all experimental conditions, the closest approximation to the empirical power of the Catellier and Muller multivariate test is obtained by adjusting power calculations with the expected number of complete cases. The utility of the method is demonstrated with a multivariate power analysis for a hypothetical oral cancer biomarkers study. We describe how to implement the method using standard, commercially available software products and give example code. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Restoration of longitudinal images.

PubMed

Hu, Y; Frieden, B R

1988-01-15

In this paper, a method of restoring longitudinal images is developed. By using the transfer function for longitudinal objects, and inverse filtering, a longitudinal image may be restored. The Fourier theory and sampling theorems for transverse images cannot be used directly in the longitudinal case. A modification and reasonable approximation are introduced. We have numerically established a necessary relationship between just-resolved longitudinal separation (after inverse filtering), noise level, and the taking conditions of object distance and lens diameter. An empirical formula is also found to well-fit the computed results. This formula may be of use for designing optical systems which are to image longitudinal details, such as in robotics or microscopy.

Modeling Learning in Doubly Multilevel Binary Longitudinal Data Using Generalized Linear Mixed Models: An Application to Measuring and Explaining Word Learning.

PubMed

Cho, Sun-Joo; Goodwin, Amanda P

2016-04-01

When word learning is supported by instruction in experimental studies for adolescents, word knowledge outcomes tend to be collected from complex data structure, such as multiple aspects of word knowledge, multilevel reader data, multilevel item data, longitudinal design, and multiple groups. This study illustrates how generalized linear mixed models can be used to measure and explain word learning for data having such complexity. Results from this application provide deeper understanding of word knowledge than could be attained from simpler models and show that word knowledge is multidimensional and depends on word characteristics and instructional contexts.

Forward-backward multiplicity fluctuation and longitudinal harmonics in high-energy nuclear collisions

DOE PAGES

Jia, Jiangyong; Radhakrishnan, Sooraj; Zhou, Mingliang

2016-04-18

In this paper, an analysis method is proposed to study the forward-backward (FB) multiplicity fluctuation in high-energy nuclear collisions, built on the earlier work of Bzdak and Teaney [Phys. Rev. C 87, 024906 (2013)]. The method allows the decomposition of the centrality dependence of average multiplicity from the dynamical event-by-event (EbyE) fluctuation of multiplicity in pseudorapidity. Application of the method to AMPT (A Multi-Phase Transport model) and HIJING (Heavy Ion Jet INteraction Generator) models shows that the long-range component of the FB correlation is captured by a few longitudinal harmonics, with the first component driven by the asymmetry in themore » number of participating nucleons in the two colliding nuclei. The higher-order longitudinal harmonics are found to be strongly damped in AMPT compared to HIJING, due to weaker short-range correlations as well as the final-state effects present in the AMPT model. Two-particle pseudorapidity correlation reveals interesting charge-dependent short-range structures that are absent in HIJING model. Lastly, the proposed method opens an avenue to elucidate the particle production mechanism and early time dynamics in heavy-ion collisions. Future analysis directions and prospects of using the pseudorapidity correlation function to understand the centrality bias in p + p, p + A, and A + A collisions are discussed.« less

Do patient and proxy agree? Long-term changes in multiple sclerosis physical impact and walking ability on patient-reported outcome scales.

PubMed

Sonder, Judith M; Balk, Lisanne J; Bosma, Libertje V A E; Polman, Chris H; Uitdehaag, Bernard M J

2014-10-01

Patient-reported outcome scales (PROs) are useful in monitoring changes in multiple sclerosis (MS) over time. Although these scales are reliable and valid measures in longitudinal studies in MS patients, it is unknown what the impact is when obtaining longitudinal data from proxies. The objective of this paper is to compare longitudinal changes in patient and proxy responses on PROs assessing physical impact of MS and walking ability. In a prospective observational study, data on the Multiple Sclerosis Impact Scale (MSIS-29 physical) and Multiple Sclerosis Walking Scale (MSWS-12) were obtained from 137 patient-proxy couples at baseline and at two-year follow-up. Demographic and disease-related variables explaining agreement or disagreement between patients and proxies were investigated using linear regression analyses. Full agreement was found in 56% (MSIS) and 62% (MSWS) of the patient-proxy couples. Complete disagreement was very rare for both scales (2% MSIS, 5% MSWS). When patients were more positive than proxies, a higher age, longer disease duration, longer patient-proxy relationship and increased levels of depression, anxiety and caregiver burden in proxies were observed. In the majority of the patient-proxy couples there was agreement. Proxies can serve as a valuable source of information, but caution remains essential when using scores from proxies. © The Author(s), 2014.

Interaction between arsenic exposure from drinking water and genetic polymorphisms on cardiovascular disease in Bangladesh: a prospective case-cohort study.

PubMed

Wu, Fen; Jasmine, Farzana; Kibriya, Muhammad G; Liu, Mengling; Cheng, Xin; Parvez, Faruque; Islam, Tariqul; Ahmed, Alauddin; Rakibuz-Zaman, Muhammad; Jiang, Jieying; Roy, Shantanu; Paul-Brutus, Rachelle; Slavkovich, Vesna; Islam, Tariqul; Levy, Diane; VanderWeele, Tyler J; Pierce, Brandon L; Graziano, Joseph H; Ahsan, Habibul; Chen, Yu

2015-05-01

Epidemiologic data on genetic susceptibility to cardiovascular effects of arsenic exposure from drinking water are limited. We investigated whether the association between well-water arsenic and cardiovascular disease (CVD) differed by 170 single nucleotide polymorphisms (SNPs) in 17 genes related to arsenic metabolism, oxidative stress, inflammation, and endothelial dysfunction. We conducted a prospective case-cohort study nested in the Health Effects of Arsenic Longitudinal Study, with a random subcohort of 1,375 subjects and 447 incident fatal and nonfatal cases of CVD. Well-water arsenic was measured in 2000 at baseline. The CVD cases, 56 of which occurred in the subcohort, included 238 coronary heart disease cases, 165 stroke cases, and 44 deaths due to other CVD identified during follow-up from 2000 to 2012. Of the 170 SNPs tested, multiplicative interactions between well-water arsenic and two SNPs, rs281432 in ICAM1 (padj = 0.0002) and rs3176867 in VCAM1 (padj = 0.035), were significant for CVD after adjustment for multiple testing. Compared with those with GC or CC genotype in rs281432 and lower well-water arsenic, the adjusted hazard ratio (aHR) for CVD was 1.82 (95% CI: 1.31, 2.54) for a 1-SD increase in well-water arsenic combined with the GG genotype, which was greater than expected given aHRs of 1.08 and 0.96 for separate effects of arsenic and the genotype alone, respectively. Similarly, the joint aHR for arsenic and the rs3176867 CC genotype was 1.34 (95% CI: 0.95, 1.87), greater than expected given aHRs for their separate effects of 1.02 and 0.84, respectively. Associations between CVD and arsenic exposure may be modified by genetic variants related to endothelial dysfunction.

A review of the handling of missing longitudinal outcome data in clinical trials

PubMed Central

2014-01-01

The aim of this review was to establish the frequency with which trials take into account missingness, and to discover what methods trialists use for adjustment in randomised controlled trials with longitudinal measurements. Failing to address the problems that can arise from missing outcome data can result in misleading conclusions. Missing data should be addressed as a means of a sensitivity analysis of the complete case analysis results. One hundred publications of randomised controlled trials with longitudinal measurements were selected randomly from trial publications from the years 2005 to 2012. Information was extracted from these trials, including whether reasons for dropout were reported, what methods were used for handing the missing data, whether there was any explanation of the methods for missing data handling, and whether a statistician was involved in the analysis. The main focus of the review was on missing data post dropout rather than missing interim data. Of all the papers in the study, 9 (9%) had no missing data. More than half of the papers included in the study failed to make any attempt to explain the reasons for their choice of missing data handling method. Of the papers with clear missing data handling methods, 44 papers (50%) used adequate methods of missing data handling, whereas 30 (34%) of the papers used missing data methods which may not have been appropriate. In the remaining 17 papers (19%), it was difficult to assess the validity of the methods used. An imputation method was used in 18 papers (20%). Multiple imputation methods were introduced in 1987 and are an efficient way of accounting for missing data in general, and yet only 4 papers used these methods. Out of the 18 papers which used imputation, only 7 displayed the results as a sensitivity analysis of the complete case analysis results. 61% of the papers that used an imputation explained the reasons for their chosen method. Just under a third of the papers made no reference to reasons for missing outcome data. There was little consistency in reporting of missing data within longitudinal trials. PMID:24947664

Melorheostosis of the Foot: A Case Report of A rare entity with a Review of Multimodality Imaging Emphasizing the Importance of Conventional Radiography in Diagnosis

PubMed Central

Ashish, Gulia; Shashikant, Juvekar; Ajay, Puri; Subhash, Desai

2016-01-01

Introduction: Melorheostosis is a benign bone dysplasia affecting predominantly the appendicular skeleton and adjoining soft tissues. The diagnosis can be established on plain radiographs alone and advanced imaging modalities can be avoided. We hereby report a rare case of melorheostosis affecting the foot with a review of the role of various imaging modalities in diagnosis of this rare bone dysplasia. Case Report: We present the case of a 29 years old man who was diagnosed with melorheostosis affecting his left foot. The patient presented to the outpatient department of our tertiary care referral hospital with complains of pain in the left ankle and foot with imaging and evaluation done at a primary center. The radiograph revealed an irregular, longitudinal extraosseous hyperostosis along the body of the calcaneum and the metacarpals which was consistent with the classical radiological description of melorheostosis. The CT, MRI and bone scan findings corroborated our primary diagnosis. Conclusion: The purpose of this case report is to review the features of this rare disorder affecting the foot, on multiple imaging modalities and emphasizing the role of conventional radiology in its diagnosis. PMID:27299136

Perceptions of Critical Thinking, Task Value, Autonomy and Science Lab Self-Efficacy: A Longitudinal Examination of Students' CASE Experience

ERIC Educational Resources Information Center

Velez, Jonathan J.; Lambert, Misty D.; Elliott, Kristopher M.

2015-01-01

The purpose of this study was to begin examining the impact of the Curriculum for Agricultural Science Education (CASE). Under development since 2008, the curriculum is intended to integrate core academics and Science, Technology, Engineering, and Math (STEM) into agricultural education programs. This longitudinal descriptive correlational study…

Using Evidence in L2 Argumentative Writing: A Longitudinal Case Study across High School and University

ERIC Educational Resources Information Center

Kibler, Amanda K.; Hardigree, Christine

2017-01-01

This 8-year longitudinal case study of Fabiola, a Spanish-English bilingual, investigated her argumentative writing development, focusing on her use of evidence to support and develop arguments over time from high school through university. Data sources included 36 writing samples. Texts across grade levels and course types were analyzed to…

Code-Switching and Gender: A Longitudinal Study of Spanish/English Speaking Fraternal Boy-Girl Twins

ERIC Educational Resources Information Center

Robinson, Colin

2015-01-01

Researchers from Jean Piaget (1932) to Sehlauoi (2008) have utilized small case studies to intensively examine naturally occurring child language production in the home environment. This qualitative, 5-year longitudinal, five-year case study continues the focus of previous research on child bilingualism and code-switching; however, it aims to…

Dynamics of Complexity and Accuracy: A Longitudinal Case Study of Advanced Untutored Development

ERIC Educational Resources Information Center

Polat, Brittany; Kim, Youjin

2014-01-01

This longitudinal case study follows a dynamic systems approach to investigate an under-studied research area in second language acquisition, the development of complexity and accuracy for an advanced untutored learner of English. Using the analytical tools of dynamic systems theory (Verspoor et al. 2011) within the framework of complexity,…

Bias in Cross-Sectional Analyses of Longitudinal Mediation: Partial and Complete Mediation under an Autoregressive Model

ERIC Educational Resources Information Center

Maxwell, Scott E.; Cole, David A.; Mitchell, Melissa A.

2011-01-01

Maxwell and Cole (2007) showed that cross-sectional approaches to mediation typically generate substantially biased estimates of longitudinal parameters in the special case of complete mediation. However, their results did not apply to the more typical case of partial mediation. We extend their previous work by showing that substantial bias can…

Individuals with Single Versus Multiple Suicide Attempts Over 10 Years of Prospective Follow-Up

PubMed Central

Boisseau, Christina L.; Yen, Shirley; Markowitz, John C.; Grilo, Carlos M.; Sanislow, Charles A.; Shea, M. Tracie; Zanarini, Mary C.; Skodol, Andrew E.; Gunderson, John G.; Morey, Leslie C.; McGlashan, Thomas H.

2012-01-01

Background The study attempted to identify characteristics that differentiate multiple suicide attempters from single attempters in individuals with personality disorders (PDs) and/or major depression. Method Participants were 431 participants enrolled in the Collaborative Longitudinal Study of Personality Disorders from July 1996 to June 2008. Suicide attempts were assessed with the Longitudinal Interval Follow-up Evaluation at 6 and 12 months, then yearly through 10 years. Logistic regression was used to compare single attempters to multiple attempters on Axis I and II psychiatric disorders and personality trait variables. Results Twenty-one percent of participants attempted suicide during the 10 years of observation, with 39 (9.0%) reporting a single suicide attempt and 54 (12.5%) reporting multiple suicide attempts. Although no significant differences in were found in baseline Axis I disorders, multiple attempters were significantly more likely to meet criteria for borderline personality disorder and to have higher impulsivity scores than single attempters. Conclusion These results underscore the importance of considering both personality disorders and traits in the assessment of suicidality. PMID:22995448

Imputation of Test Scores in the National Education Longitudinal Study of 1988 (NELS:88). Working Paper Series.

ERIC Educational Resources Information Center

Bokossa, Maxime C.; Huang, Gary G.

This report describes the imputation procedures used to deal with missing data in the National Education Longitudinal Study of 1988 (NELS:88), the only current National Center for Education Statistics (NCES) dataset that contains scores from cognitive tests given the same set of students at multiple time points. As is inevitable, cognitive test…

Shyness-Sensitivity and Social, School, and Psychological Adjustment in Urban Chinese Children: A Four-Wave Longitudinal Study

ERIC Educational Resources Information Center

Yang, Fan; Chen, Xinyin; Wang, Li

2015-01-01

This study examined reciprocal contributions between shyness-sensitivity and social, school, and psychological adjustment in urban Chinese children. Longitudinal data were collected once a year from Grade 3 to Grade 6 (ages 9-12 years) for 1,171 children from multiple sources. Shyness-sensitivity positively contributed to social, school, and…

Perceived Discrimination and the Adjustment of African American Youths: A Five-Year Longitudinal Analysis with Contextual Moderation Effects

ERIC Educational Resources Information Center

Brody, Gene H.; Chen, Yi-Fu; Murry, Velma McBride; Ge, Xiaojia; Simons, Ronald L.; Gibbons, Frederick X.; Gerrard, Meg; Cutrona, Carolyn E.

2006-01-01

Longitudinal links between perceived racial discrimination and later conduct problems and depressive symptoms were examined among 714 African American adolescents who were 10-12 years old at recruitment. Data were gathered 3 times over a 5-year period. Hypotheses were tested via latent curve modeling and multiple-group latent growth modeling.…

Developing Cross-Racial Self-Efficacy: A Longitudinal Examination of the Role of Cross-Racial Mastery Experiences

ERIC Educational Resources Information Center

Liang, Christopher T. H.; Prince, Jessica K.

2008-01-01

A social-cognitive model for the development of cross-racial self-efficacy was developed and tested in a longitudinal study involving a racially and culturally diverse sample of undergraduate students (N = 879). Multiple group analyses indicated that the model fit equally well for men and women and for White students and ethnic minority students.…

Variety in Parental Use of "Want" Relates to Subsequent Growth in Children's Theory of Mind

ERIC Educational Resources Information Center

Ruffman, Ted; Puri, Aastha; Galloway, Olivia; Su, Japher; Taumoepeau, Mele

2018-01-01

In 2 cross-lagged, longitudinal studies we contrasted parental talk about want in a single context versus multiple contexts. Study 1 examined thirty-two 2 year olds, with mothers describing pictures to children. Mothers could use want in zero, one, or multiple contexts. Children whose mothers used want in multiple contexts experienced a…

Work-related heat stress concerns in automotive industries: a case study from Chennai, India

PubMed Central

Ayyappan, Ramalingam; Sankar, Sambandam; Rajkumar, Paramasivan; Balakrishnan, Kalpana

2009-01-01

Background Work-related heat stress assessments, the quantification of thermal loads and their physiological consequences have mostly been performed in non-tropical developed country settings. In many developing countries (many of which are also tropical), limited attempts have been made to create detailed job-exposure profiles for various sectors. We present here a case study from Chennai in southern India that illustrates the prevalence of work-related heat stress in multiple processes of automotive industries and the efficacy of relatively simple controls in reducing prevalence of the risk through longitudinal assessments. Methods We conducted workplace heat stress assessments in automotive and automotive parts manufacturing units according to the protocols recommended by NIOSH, USA. Sites for measurements included indoor locations with process-generated heat exposure, indoor locations without direct process-generated heat exposure and outdoor locations. Nearly 400 measurements of heat stress were made over a four-year period at more than 100 locations within eight units involved with automotive or automotive parts manufacturing in greater Chennai metropolitan area. In addition, cross-sectional measurements were made in select processes of glass manufacturing and textiles to estimate relative prevalence of heat stress. Results Results indicate that many processes even in organised large-scale industries have yet to control heat stress-related hazards adequately. Upwards of 28% of workers employed in multiple processes were at risk of heat stress-related health impairment in the sectors assessed. Implications of longitudinal baseline data for assessing efficacy of interventions as well as modelling potential future impacts from climate change (through contributions from worker health and productivity impairments consequent to increases in ambient temperature) are described. Conclusions The study re-emphasises the need for recognising heat stress as an important occupational health risk in both formal and informal sectors in India. Making available good baseline data is critical for estimating future impacts. PMID:20052426

A Green's function method for two-dimensional reactive solute transport in a parallel fracture-matrix system

NASA Astrophysics Data System (ADS)

Chen, Kewei; Zhan, Hongbin

2018-06-01

The reactive solute transport in a single fracture bounded by upper and lower matrixes is a classical problem that captures the dominant factors affecting transport behavior beyond pore scale. A parallel fracture-matrix system which considers the interaction among multiple paralleled fractures is an extension to a single fracture-matrix system. The existing analytical or semi-analytical solution for solute transport in a parallel fracture-matrix simplifies the problem to various degrees, such as neglecting the transverse dispersion in the fracture and/or the longitudinal diffusion in the matrix. The difficulty of solving the full two-dimensional (2-D) problem lies in the calculation of the mass exchange between the fracture and matrix. In this study, we propose an innovative Green's function approach to address the 2-D reactive solute transport in a parallel fracture-matrix system. The flux at the interface is calculated numerically. It is found that the transverse dispersion in the fracture can be safely neglected due to the small scale of fracture aperture. However, neglecting the longitudinal matrix diffusion would overestimate the concentration profile near the solute entrance face and underestimate the concentration profile at the far side. The error caused by neglecting the longitudinal matrix diffusion decreases with increasing Peclet number. The longitudinal matrix diffusion does not have obvious influence on the concentration profile in long-term. The developed model is applied to a non-aqueous-phase-liquid (DNAPL) contamination field case in New Haven Arkose of Connecticut in USA to estimate the Trichloroethylene (TCE) behavior over 40 years. The ratio of TCE mass stored in the matrix and the injected TCE mass increases above 90% in less than 10 years.

It's Deja Vu All over Again: Using Multiple-Spell Discrete-Time Survival Analysis.

ERIC Educational Resources Information Center

Willett, John B.; Singer, Judith D.

1995-01-01

The multiple-spell discrete-time survival analysis method is introduced and illustrated using longitudinal data on exit from and reentry into the teaching profession. The method is applicable to many educational problems involving the sequential occurrence of disparate events or episodes. (SLD)

Effects of an Incentive Based Budgeting System on Institutional Performance Indicators: An Exploratory Longitudinal Case Study of a Public University

ERIC Educational Resources Information Center

Willett, Michael S.

2013-01-01

The purpose of this exploratory longitudinal case study was to examine how the implementation of an Incentive Based Budgeting (IBB) system (i.e., Responsibility-Centered Management [RCM]) affected selected institutional performance indicators at the campus level and two comparable schools at a large Mid-Western public University. The value of…

Exploring the Evolution of a Teacher Professional Learning Community: A Longitudinal Case Study at a Taiwanese High School

ERIC Educational Resources Information Center

Chen, Peiying; Wang, Ting

2015-01-01

This article presents findings of a longitudinal case study conducted at a Taiwanese high school from 2006 to 2010. This school participated in the 'High Scope Programme' (HSP), which was sponsored by the Taiwanese National Science Council to promote curricular innovation in science education. Utilising interview data with 11 participating…

The Effects of CLIL on Oral Comprehension and Production: A Longitudinal Case Study

ERIC Educational Resources Information Center

Pérez Cañado, María Luisa; Lancaster, Nina Karen

2017-01-01

This article reports on the outcomes of a longitudinal case study to gauge the impact of content and language integrated learning (CLIL) on two of the least researched language skills: oral comprehension and production. It worked with 24 students in the fourth grade of Compulsory Secondary Education in a public school in Andalusia (southern Spain)…

The Development of Case Studies as a Method within a Longitudinal Study of Special Educational Needs Provision in the Republic of Ireland

ERIC Educational Resources Information Center

Rose, Richard; Shevlin, Michael

2016-01-01

When developing case studies within a longitudinal study of special educational needs provision within the Republic of Ireland, the authors were conscious of the critiques of the use of this approach within educational research. The difficulties associated with generalisation, challenges of ensuring trustworthiness and the possibilities of…

Development and Evaluation of a Longitudinal Case-Based Learning (CBL) Experience for a Geriatric Medicine Rotation

ERIC Educational Resources Information Center

Struck, Bryan D.; Teasdale, Thomas A.

2008-01-01

The DWR Department of Geriatric Medicine at OUHSC and the OKC VA Medical Center began a mandatory third-year geriatric medicine clerkship in 2003. As part of the didactic sessions, the Department created a longitudinal Case-Based Learning (CBL) experience. The purpose of this paper is to describe the CBL experience, report student satisfaction…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaudoin, B.; Haber, I.; Kishek, R. A.

An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifthmore » turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.« less

A research about characteristics of longitudinal variations of ES layers irregularities based on CHAMP occultation measurements

NASA Astrophysics Data System (ADS)

Liao, Sunmin

2018-04-01

Based on the data of CHAMP occultation measurements, this paper makes a preliminary analysis of the longitudinal variations of ES irregular structure by using Fourier decomposition and reconstruction technique. It is found that the longitudinal variations of the ES irregular structure show the features of multiple wave-numbers, which is dominated by the wave number 1 to the wave number 5 components, and decrease from the amplitudes of the wave number 6 components. The features of wave number structures are very different in different DIP latitude and different seasons. The number of crests in summer and autumn is mostly 3 or 4 crest structures, while the number of crests in spring achieves 5 at DIP 15°N with small fluctuates, the crests number of winter is the least. In the multiple wave-numbers structure, the wave number 4 component shows a significant dependence on the season, mainly in the summer and autumn, particularly obvious from July to October.

Child, Parent, and Peer Predictors of Early-Onset Substance Use: A Multisite Longitudinal Study

PubMed Central

Kaplow, Julie B.; Curran, Patrick J.; Dodge, Kenneth A.

2009-01-01

The purpose of this study was to identify kindergarten-age predictors of early-onset substance use from demographic, environmental, parenting, child psychological, behavioral, and social functioning domains. Data from a longitudinal study of 295 children were gathered using multiple-assessment methods and multiple informants in kindergarten and 1st grade. Annual assessments at ages 10, 11, and 12 reflected that 21% of children reported having initiated substance use by age 12. Results from longitudinal logistic regression models indicated that risk factors at kindergarten include being male, having a parent who abused substances, lower levels of parental verbal reasoning, higher levels of overactivity, more thought problems, and more social problem solving skills deficits. Children with no risk factors had less than a 10% chance of initiating substance use by age 12, whereas children with 2 or more risk factors had greater than a 50% chance of initiating substance use. Implications for typology, etiology, and prevention are discussed. PMID:12041707

Individual and social determinants of multiple chronic disease behavioral risk factors among youth.

PubMed

Alamian, Arsham; Paradis, Gilles

2012-03-22

Behavioral risk factors are known to co-occur among youth, and to increase risks of chronic diseases morbidity and mortality later in life. However, little is known about determinants of multiple chronic disease behavioral risk factors, particularly among youth. Previous studies have been cross-sectional and carried out without a sound theoretical framework. Using longitudinal data (n = 1135) from Cycle 4 (2000-2001), Cycle 5 (2002-2003) and Cycle 6 (2004-2005) of the National Longitudinal Survey of Children and Youth, a nationally representative sample of Canadian children who are followed biennially, the present study examines the influence of a set of conceptually-related individual/social distal variables (variables situated at an intermediate distance from behaviors), and individual/social ultimate variables (variables situated at an utmost distance from behaviors) on the rate of occurrence of multiple behavioral risk factors (physical inactivity, sedentary behavior, tobacco smoking, alcohol drinking, and high body mass index) in a sample of children aged 10-11 years at baseline. Multiple behavioral risk factors were assessed using a multiple risk factor score. All statistical analyses were performed using SAS, version 9.1, and SUDAAN, version 9.01. Multivariate longitudinal Poisson models showed that social distal variables including parental/peer smoking and peer drinking (Log-likelihood ratio (LLR) = 187.86, degrees of freedom (DF) = 8, p < .001), as well as individual distal variables including low self-esteem (LLR = 76.94, DF = 4, p < .001) increased the rate of occurrence of multiple behavioral risk factors. Individual ultimate variables including age, sex, and anxiety (LLR = 9.34, DF = 3, p < .05), as well as social ultimate variables including family socioeconomic status, and family structure (LLR = 10.93, DF = 5, p = .05) contributed minimally to the rate of co-occurrence of behavioral risk factors. The results suggest targeting individual/social distal variables in prevention programs of multiple chronic disease behavioral risk factors among youth.

Longitudinal Study Using a Standardized Test Battery as Predictors of Student Outcomes in a Rural County School System.

ERIC Educational Resources Information Center

Twale, Darla J.; Thompson, Mary J.

This longitudinal study focused on predicting student outcomes through multiple test scores and vocational preferences using standardized instruments and self-reports of career plans. A total of 444 students in the class of 1986 were enrolled in either a non-vocational or vocational curriculum at one of 4 high schools in a small, rural,…

A Comparison of Three IRT Approaches to Examinee Ability Change Modeling in a Single-Group Anchor Test Design

ERIC Educational Resources Information Center

Paek, Insu; Park, Hyun-Jeong; Cai, Li; Chi, Eunlim

2014-01-01

Typically a longitudinal growth modeling based on item response theory (IRT) requires repeated measures data from a single group with the same test design. If operational or item exposure problems are present, the same test may not be employed to collect data for longitudinal analyses and tests at multiple time points are constructed with unique…

A comparison of multiple imputation methods for handling missing values in longitudinal data in the presence of a time-varying covariate with a non-linear association with time: a simulation study.

PubMed

De Silva, Anurika Priyanjali; Moreno-Betancur, Margarita; De Livera, Alysha Madhu; Lee, Katherine Jane; Simpson, Julie Anne

2017-07-25

Missing data is a common problem in epidemiological studies, and is particularly prominent in longitudinal data, which involve multiple waves of data collection. Traditional multiple imputation (MI) methods (fully conditional specification (FCS) and multivariate normal imputation (MVNI)) treat repeated measurements of the same time-dependent variable as just another 'distinct' variable for imputation and therefore do not make the most of the longitudinal structure of the data. Only a few studies have explored extensions to the standard approaches to account for the temporal structure of longitudinal data. One suggestion is the two-fold fully conditional specification (two-fold FCS) algorithm, which restricts the imputation of a time-dependent variable to time blocks where the imputation model includes measurements taken at the specified and adjacent times. To date, no study has investigated the performance of two-fold FCS and standard MI methods for handling missing data in a time-varying covariate with a non-linear trajectory over time - a commonly encountered scenario in epidemiological studies. We simulated 1000 datasets of 5000 individuals based on the Longitudinal Study of Australian Children (LSAC). Three missing data mechanisms: missing completely at random (MCAR), and a weak and a strong missing at random (MAR) scenarios were used to impose missingness on body mass index (BMI) for age z-scores; a continuous time-varying exposure variable with a non-linear trajectory over time. We evaluated the performance of FCS, MVNI, and two-fold FCS for handling up to 50% of missing data when assessing the association between childhood obesity and sleep problems. The standard two-fold FCS produced slightly more biased and less precise estimates than FCS and MVNI. We observed slight improvements in bias and precision when using a time window width of two for the two-fold FCS algorithm compared to the standard width of one. We recommend the use of FCS or MVNI in a similar longitudinal setting, and when encountering convergence issues due to a large number of time points or variables with missing values, the two-fold FCS with exploration of a suitable time window.

Joint principal trend analysis for longitudinal high-dimensional data.

PubMed

Zhang, Yuping; Ouyang, Zhengqing

2018-06-01

We consider a research scenario motivated by integrating multiple sources of information for better knowledge discovery in diverse dynamic biological processes. Given two longitudinal high-dimensional datasets for a group of subjects, we want to extract shared latent trends and identify relevant features. To solve this problem, we present a new statistical method named as joint principal trend analysis (JPTA). We demonstrate the utility of JPTA through simulations and applications to gene expression data of the mammalian cell cycle and longitudinal transcriptional profiling data in response to influenza viral infections. © 2017, The International Biometric Society.

Association analysis of whole genome sequencing data accounting for longitudinal and family designs.

PubMed

Hu, Yijuan; Hui, Qin; Sun, Yan V

2014-01-01

Using the whole genome sequencing data and the simulated longitudinal phenotypes for 849 pedigree-based individuals from Genetic Analysis Workshop 18, we investigated various approaches to detecting the association of rare and common variants with blood pressure traits. We compared three strategies for longitudinal data: (a) using the baseline measurement only, (b) using the average from multiple visits, and (c) using all individual measurements. We also compared the power of using all of the pedigree-based data and the unrelated subset. The analyses were performed without knowledge of the underlying simulating model.

Long term outcome of neonatal meningitis

PubMed Central

Stevens, J; Eames, M; Kent, A; Halket, S; Holt, D; Harvey, D

2003-01-01

Objectives: To quantify long term impairment after neonatal meningitis. Design: Longitudinal case-control study over 9–10 years. Subjects and methods: A total of 111 children who had suffered neonatal meningitis were seen and compared with 113 matched controls from their birth hospital and 49 controls from general practices. Assessments included the WISC IIIUK , movement assessment battery for children (mABC), audiometry, vision testing, and social and medical data. Statistical analysis was by multiple regression, analysis of variance, and χ2 tests. Results: Some 10.8% of cases had a severe and 9% a moderate overall outcome compared with 0% and 1.8% for the hospital controls. The mean intelligence quotient (IQ) of the cases (88.8) was significantly less than that of the hospital controls (99.4) or the GP controls (99.6) . The mABC score was significantly worse for the cases (7.08) than the hospital (5) or GP (4) controls. Some 3.6% of cases had sensorineural hearing loss, 2.7% had persisting hydrocephalus; no controls did. Some 5.4% of cases and 1.7% of hospital controls had treatment for seizures. Conclusions: Severe neurodisability and milder motor and psychometric impairment result from neonatal meningitis. Both clinical follow up and comprehensive developmental assessment are needed after this disease. PMID:12719389

Use of missing data methods in longitudinal studies: the persistence of bad practices in developmental psychology.

PubMed

Jelicić, Helena; Phelps, Erin; Lerner, Richard M

2009-07-01

Developmental science rests on describing, explaining, and optimizing intraindividual changes and, hence, empirically requires longitudinal research. Problems of missing data arise in most longitudinal studies, thus creating challenges for interpreting the substance and structure of intraindividual change. Using a sample of reports of longitudinal studies obtained from three flagship developmental journals-Child Development, Developmental Psychology, and Journal of Research on Adolescence-we examined the number of longitudinal studies reporting missing data and the missing data techniques used. Of the 100 longitudinal studies sampled, 57 either reported having missing data or had discrepancies in sample sizes reported for different analyses. The majority of these studies (82%) used missing data techniques that are statistically problematic (either listwise deletion or pairwise deletion) and not among the methods recommended by statisticians (i.e., the direct maximum likelihood method and the multiple imputation method). Implications of these results for developmental theory and application, and the need for understanding the consequences of using statistically inappropriate missing data techniques with actual longitudinal data sets, are discussed.

Configurations of Multiple Disparities in Reading Performance: Longitudinal Observations across France, Germany, Sweden and the United Kingdom

ERIC Educational Resources Information Center

Lenkeit, Jenny; Schwippert, Knut; Knigge, Michel

2018-01-01

Research provides evidence that gender, immigrant background and socio-economic characteristics present multiple disadvantaging characteristics that change their relative importance and configurations over time. When evaluating inequalities researchers tend to focus on one particular aspect and often use composite measures when evaluating…

Application of the Levenshtein Distance Metric for the Construction of Longitudinal Data Files

ERIC Educational Resources Information Center

Doran, Harold C.; van Wamelen, Paul B.

2010-01-01

The analysis of longitudinal data in education is becoming more prevalent given the nature of testing systems constructed for No Child Left Behind Act (NCLB). However, constructing the longitudinal data files remains a significant challenge. Students move into new schools, but in many cases the unique identifiers (ID) that should remain constant…

Disclosure of disease status among employed multiple sclerosis patients: association with negative work events and accommodations.

PubMed

Frndak, Seth E; Kordovski, Victoria M; Cookfair, Diane; Rodgers, Jonathan D; Weinstock-Guttman, Bianca; Benedict, Ralph H B

2015-02-01

Unemployment is common in multiple sclerosis (MS) and detrimental to quality of life. Studies suggest disclosure of diagnosis is an adaptive strategy for patients. However, the role of cognitive deficits and psychiatric symptoms in disclosure are not well studied. The goals of this paper were to (a) determine clinical factors most predictive of disclosure, and (b) measure the effects of disclosure on workplace problems and accommodations in employed patients. We studied two overlapping cohorts: a cross-sectional sample (n = 143) to determine outcomes associated with disclosure, and a longitudinal sample (n = 103) compared at four time points over one year on reported problems and accommodations. A case study of six patients, disclosing during monitoring, was also included. Disclosure was associated with greater physical disability but not cognitive impairment. Logistic regression predicting disclosure status retained physical disability, accommodations and years of employment (p < 0.0001). Disclosed patients reported more work problems and accommodations over time. The case study revealed that reasons for disclosing are multifaceted, including connection to employer, decreased mobility and problems at work. Although cognitive impairment is linked to unemployment, it does not appear to inform disclosure decisions. Early disclosure may help maintain employment if followed by appropriate accommodations. © The Author(s), 2014.

SUMMIT (Serially Unified Multicenter Multiple Sclerosis Investigation): creating a repository of deeply phenotyped contemporary multiple sclerosis cohorts.

PubMed

Bove, Riley; Chitnis, Tanuja; Cree, Bruce Ac; Tintoré, Mar; Naegelin, Yvonne; Uitdehaag, Bernard Mj; Kappos, Ludwig; Khoury, Samia J; Montalban, Xavier; Hauser, Stephen L; Weiner, Howard L

2017-08-01

There is a pressing need for robust longitudinal cohort studies in the modern treatment era of multiple sclerosis. Build a multiple sclerosis (MS) cohort repository to capture the variability of disability accumulation, as well as provide the depth of characterization (clinical, radiologic, genetic, biospecimens) required to adequately model and ultimately predict a patient's course. Serially Unified Multicenter Multiple Sclerosis Investigation (SUMMIT) is an international multi-center, prospectively enrolled cohort with over a decade of comprehensive follow-up on more than 1000 patients from two large North American academic MS Centers (Brigham and Women's Hospital (Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women's Hospital (CLIMB; BWH)) and University of California, San Francisco (Expression/genomics, Proteomics, Imaging, and Clinical (EPIC))). It is bringing online more than 2500 patients from additional international MS Centers (Basel (Universitätsspital Basel (UHB)), VU University Medical Center MS Center Amsterdam (MSCA), Multiple Sclerosis Center of Catalonia-Vall d'Hebron Hospital (Barcelona clinically isolated syndrome (CIS) cohort), and American University of Beirut Medical Center (AUBMC-Multiple Sclerosis Interdisciplinary Research (AMIR)). We provide evidence for harmonization of two of the initial cohorts in terms of the characterization of demographics, disease, and treatment-related variables; demonstrate several proof-of-principle analyses examining genetic and radiologic predictors of disease progression; and discuss the steps involved in expanding SUMMIT into a repository accessible to the broader scientific community.

Characterizing facial features in individuals with craniofacial microsomia: A systematic approach for clinical research.

PubMed

Heike, Carrie L; Wallace, Erin; Speltz, Matthew L; Siebold, Babette; Werler, Martha M; Hing, Anne V; Birgfeld, Craig B; Collett, Brent R; Leroux, Brian G; Luquetti, Daniela V

2016-11-01

Craniofacial microsomia (CFM) is a congenital condition with wide phenotypic variability, including hypoplasia of the mandible and external ear. We assembled a cohort of children with facial features within the CFM spectrum and children without known craniofacial anomalies. We sought to develop a standardized approach to assess and describe the facial characteristics of the study cohort, using multiple sources of information gathered over the course of this longitudinal study and to create case subgroups with shared phenotypic features. Participants were enrolled between 1996 and 2002. We classified the facial phenotype from photographs, ratings using a modified version of the Orbital, Ear, Mandible, Nerve, Soft tissue (OMENS) pictorial system, data from medical record abstraction, and health history questionnaires. The participant sample included 142 cases and 290 controls. The average age was 13.5 years (standard deviation, 1.3 years; range, 11.1-17.1 years). Sixty-one percent of cases were male, 74% were white non-Hispanic. Among cases, the most common features were microtia (66%) and mandibular hypoplasia (50%). Case subgroups with meaningful group definitions included: (1) microtia without other CFM-related features (n = 24), (2) microtia with mandibular hypoplasia (n = 46), (3) other combinations of CFM- related facial features (n = 51), and (4) atypical features (n = 21). We developed a standardized approach for integrating multiple data sources to phenotype individuals with CFM, and created subgroups based on clinically-meaningful, shared characteristics. We hope that this system can be used to explore associations between phenotype and clinical outcomes of children with CFM and to identify the etiology of CFM. Birth Defects Research (Part A) 106:915-926, 2016.© 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Participation Dynamics in Population-Based Longitudinal HIV Surveillance in Rural South Africa

PubMed Central

Larmarange, Joseph; Mossong, Joël; Bärnighausen, Till; Newell, Marie Louise

2015-01-01

Population-based HIV surveillance is crucial to inform understanding of the HIV pandemic and evaluate HIV interventions, but little is known about longitudinal participation patterns in such settings. We investigated the dynamics of longitudinal participation patterns in a high HIV prevalence surveillance setting in rural South Africa between 2003 and 2012, taking into account demographic dynamics. At any given survey round, 22,708 to 30,495 persons were eligible. Although the yearly participation rates were relatively modest (26% to 46%), cumulative rates increased substantially with multiple recruitment opportunities: 68% of eligible persons participated at least once, 48% at least twice and 31% at least three times after five survey rounds. We identified two types of study fatigue: at the individual level, contact and consent rates decreased with multiple recruitment opportunities and, at the population level, these rates also decreased over calendar time, independently of multiple recruitment opportunities. Using sequence analysis and hierarchical clustering, we identified three broad individual participation profiles: consenters (20%), switchers (43%) and refusers (37%). Men were over represented among refusers, women among consenters, and temporary non-residents among switchers. The specific subgroup of persons who were systemically not contacted or refusers constitutes a challenge for population-based surveillance and interventions. PMID:25875851

Tracing Beliefs and Behaviors of a Participant in a Longitudinal Study for the Development of Mathematical Ideas and Reasoning: A Case Study

ERIC Educational Resources Information Center

Steffero, Maria

2010-01-01

This research provides an analysis of the relationship between a student's beliefs and mathematical behaviors over a seventeen-year period. Romina, the student of focus in this case study, was among the original participants in a longitudinal study which explored how students build mathematical ideas when working collaboratively on problem-solving…

The Combined Quantification and Interpretation of Multiple Quantitative Magnetic Resonance Imaging Metrics Enlightens Longitudinal Changes Compatible with Brain Repair in Relapsing-Remitting Multiple Sclerosis Patients.

PubMed

Bonnier, Guillaume; Maréchal, Benedicte; Fartaria, Mário João; Falkowskiy, Pavel; Marques, José P; Simioni, Samanta; Schluep, Myriam; Du Pasquier, Renaud; Thiran, Jean-Philippe; Krueger, Gunnar; Granziera, Cristina

2017-01-01

Quantitative and semi-quantitative MRI (qMRI) metrics provide complementary specificity and differential sensitivity to pathological brain changes compatible with brain inflammation, degeneration, and repair. Moreover, advanced magnetic resonance imaging (MRI) metrics with overlapping elements amplify the true tissue-related information and limit measurement noise. In this work, we combined multiple advanced MRI parameters to assess focal and diffuse brain changes over 2 years in a group of early-stage relapsing-remitting MS patients. Thirty relapsing-remitting MS patients with less than 5 years disease duration and nine healthy subjects underwent 3T MRI at baseline and after 2 years including T1, T2, T2* relaxometry, and magnetization transfer imaging. To assess longitudinal changes in normal-appearing (NA) tissue and lesions, we used analyses of variance and Bonferroni correction for multiple comparisons. Multivariate linear regression was used to assess the correlation between clinical outcome and multiparametric MRI changes in lesions and NA tissue. In patients, we measured a significant longitudinal decrease of mean T2 relaxation times in NA white matter ( p  = 0.005) and a decrease of T1 relaxation times in the pallidum ( p  < 0.05), which are compatible with edema reabsorption and/or iron deposition. No longitudinal changes in qMRI metrics were observed in controls. In MS lesions, we measured a decrease in T1 relaxation time ( p -value < 2.2e-16) and a significant increase in MTR ( p -value < 1e-6), suggesting repair mechanisms, such as remyelination, increased axonal density, and/or a gliosis. Last, the evolution of advanced MRI metrics-and not changes in lesions or brain volume-were correlated to motor and cognitive tests scores evolution (Adj- R 2  > 0.4, p  < 0.05). In summary, the combination of multiple advanced MRI provided evidence of changes compatible with focal and diffuse brain repair at early MS stages as suggested by histopathological studies.

Asymptotic Laws of Thermovibrational Convecton in a Horizontal Fluid Layer

NASA Astrophysics Data System (ADS)

Smorodin, B. L.; Myznikova, B. I.; Keller, I. O.

2017-02-01

Theoretical study of convective instability is applied to a horizontal layer of incompressible single-component fluid subjected to the uniform steady gravity, longitudinal vibrations of arbitrary frequency and initial temperature difference. The mathematical model of thermovibrational convection has the form of initial boundary value problem for the Oberbeck-Boussinesq system of equations. The problems are solved using different simulation strategies, like the method of averaging, method of multiple scales, Galerkin approach, Wentzel-Kramers-Brillouin method and Floquet technique. The numerical analysis has shown that the effect of vibrations on the stability threshold is complex: vibrations can either stabilize or destabilize the basic state depending on values of the parameters. The influence of the Prandtl number on the instability thresholds is investigated. The asymptotic behaviour of critical values of the parameters is studied in two limiting cases: (i) small amplitude and (ii) low frequency of vibration. In case (i), the instability is due to the influence of thermovibrational mechanism on the classical Rayleigh-Benard convective instability. In case (ii), the nature of the instability is related to the instability of oscillating counter-streams with a cubic profile.

A Case Study of an Emerging Visual Artist with Frontotemporal Lobar Degeneration and Amyotrophic Lateral Sclerosis

PubMed Central

Liu, Anli; Werner, Kelly; Roy, Subhojit; Trojanowski, John Q.; Morgan-Kane, Ursula; Miller, Bruce L.; Rankin, Katherine P.

2009-01-01

Patients with presenting with left-sided FTLD syndromes sometimes develop a new preoccupation with art, greater attention to visual stimuli, and increased visual creativity. We describe the case of a 53-year-old, right-handed man with a history of bipolar disorder who presented with language and behavior impairments characteristic of FTLD, then developed motor symptoms consistent with a second diagnosis of amyotrophic lateral sclerosis. Though the patient had never created visual art before, he developed a compulsion for painting beginning at the earliest stages of his disease, and continued producing art daily until he could no longer lift a paintbrush because of his motor deficits. Upon autopsy, he was found to have ubiquitin and TDP43-positive inclusions with MND pathology. This case study details the patient’s longitudinal neuropsychological, emotional, behavioral, and motor symptoms, along with structural imaging, neurologic, and neuropathologic findings. Multiple examples of the patient’s art are depicted throughout all stages of his illness, and the possible cognitive, behavioral, and neurologic correlates of his new-onset visual artistry are discussed. PMID:19274573

An Inverse U-Shaped Curve of Resting-State Networks in Individuals at High Risk of Alzheimer's Disease.

PubMed

Ye, Qing; Chen, Haifeng; Su, Fan; Shu, Hao; Gong, Liang; Xie, Chunming; Zhou, Hong; Bai, Feng

Higher functional connectivity (FC) in resting-state networks has been shown in individuals at risk of Alzheimer's disease (AD) by many studies. However, the longitudinal trajectories of the FC remain unknown. The present 35-month follow-up study aimed to explore longitudinal changes in higher FC in multiple resting-state networks in subjects with the apolipoprotein E ε4 allele (ApoE4) and/or amnestic mild cognitive impairment (aMCI). Fifty-one subjects with aMCI and 64 cognitively normal (CN) subjects underwent neuropsychological tests and resting-state functional magnetic resonance imaging (fMRI) scans twice from April 2011 to June 2015. Subjects were divided into 4 groups according to diagnosis and ApoE4 status. The CN non-ApoE4 group served as a control group, and other groups served as AD risk groups. The cross-sectional and longitudinal patterns of multiple resting-state networks, including default mode network, hippocampus network, executive control network, and salience network, were explored by comparing FC data between groups and between time points, respectively. At baseline, compared with the control group, the AD risk groups showed higher FC with 8 regions in multiple networks. At follow-up, 6 of the regions displayed longitudinally decreased FC in AD risk groups. In contrast, the FC with all of these regions was maintained in the control group. Notably, among the 3 risk groups, most of the higher FC at baseline (5 of the 8 regions) and longitudinally decreased FC at follow-up (4 of the 6 regions) were shown in the aMCI ApoE4 group. Higher resting-state FC is followed by a decline in subjects at AD risk, and this inverse U-shaped trajectory is more notable in subjects with higher risk. © Copyright 2018 Physicians Postgraduate Press, Inc.

Multiple and multidimensional transitions from trainee to trained doctor: a qualitative longitudinal study in the UK.

PubMed

Gordon, Lisi; Jindal-Snape, Divya; Morrison, Jill; Muldoon, Janine; Needham, Gillian; Siebert, Sabina; Rees, Charlotte

2017-12-01

To explore trainee doctors' experiences of the transition to trained doctor, we answer three questions: (1) What multiple and multidimensional transitions (MMTs) are experienced as participants move from trainee to trained doctor? (2) What facilitates and hinders doctors' successful transition experiences? (3) What is the impact of MMTs on trained doctors? A qualitative longitudinal study underpinned by MMT theory. Four training areas (health boards) in the UK. 20 doctors, 19 higher-stage trainees within 6 months of completing their postgraduate training and 1 staff grade, associate specialist or specialty doctor, were recruited to the 9-month longitudinal audio-diary (LAD) study. All completed an entrance interview, 18 completed LADs and 18 completed exit interviews. Data were analysed cross-sectionally and longitudinally using thematic Framework Analysis. Participants experienced a multiplicity of expected and unexpected, positive and negative work-related transitions (eg, new roles) and home-related transitions (eg, moving home) during their trainee-trained doctor transition. Factors facilitating or inhibiting successful transitions were identified at various levels: individual (eg, living arrangements), interpersonal (eg, presence of supportive relationships), systemic (eg, mentoring opportunities) and macro (eg, the curriculum provided by Medical Royal Colleges). Various impacts of transitions were also identified at each of these four levels: individual (eg, stress), interpersonal (eg, trainees' children spending more time in childcare), systemic (eg, spending less time with patients) and macro (eg, delayed start in trainees' new roles). Priority should be given to developing supportive relationships (both formal and informal) to help trainees transition into their trained doctor roles, as well as providing more opportunities for learning. Further longitudinal qualitative research is now needed with a longer study duration to explore transition journeys for several years into the trained doctor role. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Results of endocapsular phacofracture debulking of hard cataracts.

PubMed

Davison, James A

2015-01-01

To present a phacoemulsification technique for hard cataracts and compare postoperative results using two different ultrasonic tip motions during quadrant removal. A phacoemulsification technique which employs in situ fracture and endocapsular debulking for hard cataracts is presented. The prospective study included 56 consecutive cases of hard cataract (LOCS III NC [Lens Opacification Classification System III, nuclear color], average 4.26), which were operated using the Infiniti machine and the Partial Kelman tip. Longitudinal tip movement was used for sculpting for all cases which were randomized to receive longitudinal or torsional/interjected longitudinal (Intelligent Phaco [IP]) strategies for quadrant removal. Measurements included cumulative dissipated energy (CDE), 3 months postoperative surgically induced astigmatism (SIA), and corneal endothelial cell density (ECD) losses. No complications were recorded in any of the cases. Respective overall and longitudinal vs IP means were as follows: CDE, 51.6±15.6 and 55.7±15.5 vs 48.6±15.1; SIA, 0.36±0.2 D and 0.4±0.2 D vs 0.3±0.2 D; and mean ECD loss, 4.1%±10.8% and 5.9%±13.4% vs 2.7%±7.8%. The differences between longitudinal and IP were not significant for any of the three categories. The endocapsular phacofracture debulking technique is safe and effective for phacoemulsification of hard cataracts using longitudinal or torsional IP strategies for quadrant removal with the Infiniti machine and Partial Kelman tip.

Transition from convective to absolute Raman instability via the longitudinal relativistic effect by using Vlasov-Maxwell simulations

NASA Astrophysics Data System (ADS)

Wang, Q.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Feng, Q. S.; Zhang, H. C.; He, X. T.

2018-01-01

The longitudinal relativistic effect on stimulated Raman backscattering (SRBS) is investigated by using one-dimensional (1D) Vlasov-Maxwell simulations. Using a short backscattered light seed pulse with a very small amplitude, the linear gain spectra of SRBS in the strongly convective regime is presented by combining the relativistic and non-relativistic 1D Vlasov-Maxwell simulations, which is in agreement with the steady-state linear theory. More interestingly, by considering transition from convective to absolute instability due to electron trapping, we successfully predict the critical duration of the seed which can just trigger the kinetic inflation of the excited SRBS after the seed leaves the simulation box. The critical duration in the relativistic case is much shorter than that in the nonrelativistic case, which indicates that the kinetic inflation more easily occurs in the relativistic case than in the nonrelativistic case. In the weakly convective regime, the transition from convective to absolute instability for SRBS can directly occur in the linear regime due to the longitudinal relativistic modification. For the same pump, our simulations first demonstrate that the SRBS excited by a short and small seed pulse is a convective instability in the nonrelativistic case but becomes an absolute instability due to the decrease of the linear Landau damping from the longitudinal relativistic modification in the relativistic case. In more detail, the growth rate of the backscattered light is also in excellent agreement with theoretical prediction.

The first year of practice: an investigation of the professional learning and development of promising novice physical therapists.

PubMed

Black, Lisa L; Jensen, Gail M; Mostrom, Elizabeth; Perkins, Jan; Ritzline, Pamela D; Hayward, Lorna; Blackmer, Betsy

2010-12-01

The goal in studying expertise is not merely to describe ways in which experts excel but also to understand how experts develop in order to better facilitate the development of novices. The study of novice progression helps us to understand what successful versus unsuccessful learning looks like. This understanding is critical, as autonomous practice places increased demands for advanced clinical judgments and the ability to assume professional responsibilities. The purpose of this study was to explore the experiences, learning, and development of promising novice therapists throughout their first year of practice in the United States. A longitudinal, multiple-site qualitative case study method was used for within-case and across-case analysis. A purposive sample of 11 promising new graduates from 4 physical therapist education programs participated. Investigators followed the graduates throughout their first year of practice. Data sources included: (1) semistructured interviews conducted at baseline and every 3 months thereafter for 1 year, (2) reflective journals completed at regular intervals, and (3) review of academic and clinical education records and résumés. Four themes emerged: (1) the clinical environment influenced the novice physical therapists' performance, (2) participants learned through experience and social interaction and learning was primarily directed toward self, (3) growing confidence was directly related to developing communication skills, and (4) therapists were engaged in professional identity formation and role transitions. The findings suggest there are common experiences and themes that emerge as novice physical therapists develop. Although research has been conducted on expertise in physical therapy, few longitudinal investigations have explored the development of therapists across transitions from graduate to novice to expert practitioner. This study explored and described the learning and development of graduates during their first year of practice.

Using Hand Grip Force as a Correlate of Longitudinal Acceleration Comfort for Rapid Transit Trains

PubMed Central

Guo, Beiyuan; Gan, Weide; Fang, Weining

2015-01-01

Longitudinal acceleration comfort is one of the essential metrics used to evaluate the ride comfort of train. The aim of this study was to investigate the effectiveness of using hand grip force as a correlate of longitudinal acceleration comfort of rapid transit trains. In the paper, a motion simulation system was set up and a two-stage experiment was designed to investigate the role of the grip force on the longitudinal comfort of rapid transit trains. The results of the experiment show that the incremental grip force was linearly correlated with the longitudinal acceleration value, while the incremental grip force had no correlation with the direction of the longitudinal acceleration vector. The results also show that the effects of incremental grip force and acceleration duration on the longitudinal comfort of rapid transit trains were significant. Based on multiple regression analysis, a step function model was established to predict the longitudinal comfort of rapid transit trains using the incremental grip force and the acceleration duration. The feasibility and practicably of the model was verified by a field test. Furthermore, a comparative analysis shows that the motion simulation system and the grip force based model were valid to support the laboratory studies on the longitudinal comfort of rapid transit trains. PMID:26147730

Melorheostosis of the Foot: A Case Report of A rare entity with a Review of Multimodality Imaging Emphasizing the Importance of Conventional Radiography in Diagnosis.

PubMed

Ashish, Gulia; Shashikant, Juvekar; Ajay, Puri; Subhash, Desai

2016-01-01

Melorheostosis is a benign bone dysplasia affecting predominantly the appendicular skeleton and adjoining soft tissues. The diagnosis can be established on plain radiographs alone and advanced imaging modalities can be avoided. We hereby report a rare case of melorheostosis affecting the foot with a review of the role of various imaging modalities in diagnosis of this rare bone dysplasia. We present the case of a 29 years old man who was diagnosed with melorheostosis affecting his left foot. The patient presented to the outpatient department of our tertiary care referral hospital with complains of pain in the left ankle and foot with imaging and evaluation done at a primary center. The radiograph revealed an irregular, longitudinal extraosseous hyperostosis along the body of the calcaneum and the metacarpals which was consistent with the classical radiological description of melorheostosis. The CT, MRI and bone scan findings corroborated our primary diagnosis. The purpose of this case report is to review the features of this rare disorder affecting the foot, on multiple imaging modalities and emphasizing the role of conventional radiology in its diagnosis.

Multiple cracking of unidirectional and cross-ply ceramic matrix composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, W.S.; Chou, T.W.

1995-03-01

This paper examines the multiple cracking behavior of unidirectional and cross-ply ceramic matrix composites. For unidirectional composites, a model of concentric cylinders with finite crack spacing and debonding length is introduced. Stresses in the fiber and matrix are found and then applied to predict the composite moduli. Using an energy balance method, critical stresses for matrix cracking initiation are predicted. Effects of interfacial shear stress, debonding length and bonding energy on the critical stress are studied. All the three composite systems examined show that the critical stress for the completely debonded case is lower than that for the perfectly bondedmore » case. For crossply composites, an extensive study has been made for the transverse cracking in 90{degree} plies and the matrix cracking in 0{degree} plies. One transverse cracking and four matrix cracking modes are studied, and closed-form solutions of the critical stresses are obtained. The results indicate that the case of combined matrix and transverse crackings with associated fiber/matrix interfacial sliding in the 0{degree} plies gives the lowest critical stress for matrix cracking. The theoretical predictions are compared with experimental data of SiC/CAS cross-ply composites; both results demonstrated that an increase in the transverse ply thickness reduces the critical stress for matrix cracking in the longitudinal plies. The effects of fiber volume fraction and fiber modulus on the critical stress have been quantified. Thermal residual stresses are included in the analysis.« less

The longitudinal and interactive effects of HIV status, stimulant use, and host genotype upon neurocognitive functioning.

PubMed

Levine, Andrew J; Reynolds, Sandra; Cox, Christopher; Miller, Eric N; Sinsheimer, Janet S; Becker, James T; Martin, Eileen; Sacktor, Ned

2014-06-01

Both human immunodeficiency virus (HIV)-1 infection and illicit stimulant use can adversely impact neurocognitive functioning, and these effects can be additive. However, significant variability exists such that as-of-yet unidentified exogenous and endogenous factors affect one's risk for neurocognitive impairment. Literature on both HIV and stimulant use indicates that host genetic variants in immunologic and dopamine-related genes are one such factor. In this study, the individual and interactive effects of HIV status, stimulant use, and genotype upon neurocognitive functioning were examined longitudinally over a 10-year period. Nine hundred fifty-two Caucasian HIV+ and HIV- cases from the Multicenter AIDS Cohort Study were included. All cases had at least two comprehensive neurocognitive evaluations between 1985 and 1995. Pre-highly active antiretroviral therapy (HAART) data were examined in order to avoid the confounding effect of variable drug regimens. Linear mixed models were used, with neurocognitive domain scores as the outcome variables. No four-way interactions were found, indicating that HIV and stimulant use do not interact over time to affect neurocognitive functioning as a function of genotype. Multiple three-way interactions were found that involved genotype and HIV status. All immunologically related genes found to interact with HIV status affected neurocognitive functioning in the expected direction; however, only C-C chemokine ligand 2 (CCL2) and CCL3 affected HIV+ individuals specifically. Dopamine-related genetic variants generally affected HIV-negative individuals only. Neurocognitive functioning among HIV+ individuals who also used stimulants was not significantly different from those who did not use stimulants. The findings support the role of immunologically related genetic differences in CCL2 and CCL3 in neurocognitive functioning among HIV+ individuals; however, their impact is minor. Being consistent with findings from another cohort, dopamine (DA)-related genetic differences do not appear to impact the longitudinal neurocognitive functioning of HIV+ individuals.

A two-step method for retrieving the longitudinal profile of an electron bunch from its coherent radiation

NASA Astrophysics Data System (ADS)

Pelliccia, Daniele; Sen, Tanaji

2014-11-01

The coherent radiation emitted by an electron bunch provides a diagnostic signal that can be used to estimate its longitudinal distribution. Commonly only the amplitude of the intensity spectrum can be measured and the associated phase must be calculated to obtain the bunch profile. Very recently an iterative method was proposed to retrieve this phase. However ambiguities associated with non-uniqueness of the solution are always present in the phase retrieval procedure. Here we present a method to overcome the ambiguity problem by first performing multiple independent runs of the phase retrieval procedure and then second, sorting the good solutions by means of cross-correlation analysis. Results obtained with simulated bunches of various shapes and experimental measured spectra are presented, discussed and compared with the established Kramers-Kronig method. It is shown that even when the effect of the ambiguities is strong, as is the case for a double peak in the profile, the cross-correlation post-processing is able to filter out unwanted solutions. We show that, unlike the Kramers-Kronig method, the combined approach presented is able to faithfully reconstruct complicated bunch profiles.

Mild traumatic brain injury and fatigue: a prospective longitudinal study.

PubMed

Norrie, Joan; Heitger, Marcus; Leathem, Janet; Anderson, Tim; Jones, Richard; Flett, Ross

2010-01-01

To examine fatigue prevalence, severity, predictors and co-variates over 6 months post-mild traumatic brain injury (MTBI). Longitudinal prospective study including 263 adults with MTBI. Participants completed the Fatigue Severity Scale (FSS), Rivermead Post-concussion Symptoms Questionnaire (RPSQ), Hospital Anxiety and Depression Scale (HADS) and the Short Form 36 Health Survey-Version 2 (SF-36v2). Complete data were available for 159 participants. Key measures; prevalence--RPSQ Item 6: severity--FSS. The effect of time on fatigue prevalence and severity was examined using ANOVA. Multiple regression analysis identified statistically significant covariates. Post-MTBI fatigue prevalence was 68%, 38% and 34% at 1 week, 3 and 6 months, respectively. There was a strong effect for time over the first 3 months and moderate-to-high correlations between fatigue prevalence and severity. Early fatigue strongly predicted later fatigue; depression, but not anxiety was a predictor. Fatigue was seen as laziness by family or friends in 30% of cases. Post-MTBI fatigue is a persistent post-concussion symptom, exacerbated by depression but not anxiety. It diminishes in the first 3 months and then becomes relatively stable, suggesting the optimum intervention placement is at 3 months or more post-MTBI.

The influence of network structure upon sediment routing in two disturbed catchments, East Cape, New Zealand

NASA Astrophysics Data System (ADS)

Walley, Yasmin; Tunnicliffe, Jon; Brierley, Gary

2018-04-01

Lateral inputs from hillslopes and tributaries exert a variable impact upon the longitudinal connectivity of sediment transfer in river systems with differing drainage network configurations. Network topology influences channel slope and confinement at confluence zones, thereby affecting patterns of sediment storage and the conveyance of sediments through catchments. Rates of disturbance response, patterns of sediment propagation, and the implications for connectivity and recovery were assessed in two neighbouring catchments with differing network configurations on the East Cape of New Zealand. Both catchments were subject to forest clearing in the late 1940s and a major cyclonic storm in 1988. However, reconstruction of landslide runout pathways, and characterization of connectivity using a Tokunaga framework, demonstrates different patterns and rates of sediment transfer and storage in a dendritic network relative to a more elongate, herringbone drainage network. The dendritic network has a higher rate of sediment transfer between storage sites in successive Strahler orders, whereas longitudinal connectivity along the fourth-order mainstem is disrupted by lateral sediment inputs from multiple low-order tributaries in the more elongate, herringbone network. In both cases the most dynamic ('hotspot') reaches are associated with a high degree of network side-branching.

A longitudinal analysis of nursing home outcomes.

PubMed

Porell, F; Caro, F G; Silva, A; Monane, M

1998-10-01

To investigate resident and facility attributes associated with long-term care health outcomes in nursing homes. Quarterly Management Minutes Questionnaire (MMQ) survey data for Medicaid case-mix reimbursement of nursing homes in Massachusetts from 1991 to 1994, for specification of outcomes and resident attributes. Facility attributes are specified from cost report data. Multivariate logistic and "state-dependence" regression models are estimated for survival, ADL functional status, incontinence status, and mental status outcomes from longitudinal residence histories of Medicaid residents spanning 3 to 36 months in length. Outcomes are specified to be a function of resident demographic and diagnostic attributes and facility-level operating and nurse staffing attributes. The estimated parameters for resident demographic and diagnostic attributes showed a great deal of construct validity with respect to clinical expectations regarding risk factors for adverse outcomes. Few facility attributes were associated with outcomes generally, and none was significantly associated with all four outcomes. The absence of uniform associations between facility attributes and the various long-term care health outcomes studied suggests that strong facility performance on one health outcome may coexist with much weaker performance on other outcomes. This has implications for the aggregation of individual facility performance measures on multiple outcomes and the development of overall outcome performance measures.

Estimating mono- and bi-phasic regression parameters using a mixture piecewise linear Bayesian hierarchical model

PubMed Central

Zhao, Rui; Catalano, Paul; DeGruttola, Victor G.; Michor, Franziska

2017-01-01

The dynamics of tumor burden, secreted proteins or other biomarkers over time, is often used to evaluate the effectiveness of therapy and to predict outcomes for patients. Many methods have been proposed to investigate longitudinal trends to better characterize patients and to understand disease progression. However, most approaches assume a homogeneous patient population and a uniform response trajectory over time and across patients. Here, we present a mixture piecewise linear Bayesian hierarchical model, which takes into account both population heterogeneity and nonlinear relationships between biomarkers and time. Simulation results show that our method was able to classify subjects according to their patterns of treatment response with greater than 80% accuracy in the three scenarios tested. We then applied our model to a large randomized controlled phase III clinical trial of multiple myeloma patients. Analysis results suggest that the longitudinal tumor burden trajectories in multiple myeloma patients are heterogeneous and nonlinear, even among patients assigned to the same treatment cohort. In addition, between cohorts, there are distinct differences in terms of the regression parameters and the distributions among categories in the mixture. Those results imply that longitudinal data from clinical trials may harbor unobserved subgroups and nonlinear relationships; accounting for both may be important for analyzing longitudinal data. PMID:28723910

An Historical Framework for Cohort Differences in Intelligence

PubMed Central

Schaie, K. Warner; Willis, Sherry L.; Pennak, Sara

2006-01-01

This article reviews key issues regarding the controversy on the direction and magnitude of cohort differences in intelligence. Data from the Seattle Longitudinal Study (SLS) illustrate why differences must be studied across multiple cohorts and multiple chronological ages. Differential cohort patterns for multiple dimensions of intelligence are described. A conceptual framework is suggested for the identification of historical influences important for developmental study of cohort differences. PMID:16858496

Ultrasonic input-output for transmitting and receiving longitudinal transducers coupled to same face of isotropic elastic plate

NASA Technical Reports Server (NTRS)

Williams, J. H., Jr.; Karagulle, H.; Lee, S. S.

1982-01-01

The quantitative understanding of ultrasonic nondestructive evaluation parameters such as the stress wave factor were studied. Ultrasonic input/output characteristics for an isotropic elastic plate with transmitting and receiving longitudinal transducers coupled to the same face were analyzed. The asymptotic normal stress is calculated for an isotropic elastic half space subjected to a uniform harmonic normal stress applied to a circular region at the surface. The radiated stress waves are traced within the plate by considering wave reflections at the top and bottom faces. The output voltage amplitude of the receiving transducer is estimated by considering only longitudinal waves. Agreement is found between the output voltage wave packet amplitudes and times of arrival due to multiple reflections of the longitudinal waves.

Spatiotemporal mode-locking in multimode fiber lasers

NASA Astrophysics Data System (ADS)

Wright, Logan G.; Christodoulides, Demetrios N.; Wise, Frank W.

2017-10-01

A laser is based on the electromagnetic modes of its resonator, which provides the feedback required for oscillation. Enormous progress has been made toward controlling the interactions of longitudinal modes in lasers with a single transverse mode. For example, the field of ultrafast science has been built on lasers that lock many longitudinal modes together to form ultrashort light pulses. However, coherent superposition of longitudinal and transverse modes in a laser has received little attention. We show that modal and chromatic dispersions in fiber lasers can be counteracted by strong spatial and spectral filtering. This allows locking of multiple transverse and longitudinal modes to create ultrashort pulses with a variety of spatiotemporal profiles. Multimode fiber lasers thus open new directions in studies of nonlinear wave propagation and capabilities for applications.

Political Violence and Child Adjustment: Longitudinal Tests of Sectarian Antisocial Behavior, Family Conflict and Insecurity as Explanatory Pathways

PubMed Central

Cummings, E. Mark; Merrilees, Christine E.; Schermerhorn, Alice C.; Goeke-Morey, Marcie C.; Shirlow, Peter; Cairns, Ed

2011-01-01

Understanding the impact of political violence on child maladjustment is a matter of international concern. Recent research has advanced a social ecological explanation for relations between political violence and child adjustment. However, conclusions are qualified by the lack of longitudinal tests. Towards examining pathways longitudinally, mothers and their adolescents (M = 12.33, SD =1.78, at time 1) from two-parent families in Catholic and Protestant working class neighborhoods in Belfast, Northern Ireland, completed measures assessing multiple levels of a social ecological model. Utilizing autoregressive controls, a three-wave longitudinal model test (T1, n = 299; T2, n = 248; T3, n = 197) supported a specific pathway linking sectarian community violence, family conflict, children’s insecurity about family relationships, and adjustment problems. PMID:22313052

Achievement, Motivation, and Educational Choices: A Longitudinal Study of Expectancy and Value Using a Multiplicative Perspective

ERIC Educational Resources Information Center

Guo, Jiesi; Parker, Philip D.; Marsh, Herbert W.; Morin, Alexandre J. S.

2015-01-01

Drawing on the expectancy-value model, the present study explored individual and gender differences in university entry and selection of educational pathway (e.g., science, technology, engineering, and mathematics [STEM] course selection). In particular, we examined the multiplicative effects of expectancy and task values on educational outcomes…

Multilevel Modeling: Overview and Applications to Research in Counseling Psychology

ERIC Educational Resources Information Center

Kahn, Jeffrey H.

2011-01-01

Multilevel modeling (MLM) is rapidly becoming the standard method of analyzing nested data, for example, data from students within multiple schools, data on multiple clients seen by a smaller number of therapists, and even longitudinal data. Although MLM analyses are likely to increase in frequency in counseling psychology research, many readers…

Mexican American Adolescents' Profiles of Risk and Mental Health: A Person-Centered Longitudinal Approach

ERIC Educational Resources Information Center

Zeiders, Katharine H.; Roosa, Mark W.; Knight, George P.; Gonzales, Nancy A.

2013-01-01

Although Mexican American adolescents experience multiple risk factors in their daily lives, most research examines the influences of risk factors on adjustment independently, ignoring the additive and interactive effects of multiple risk factors. Guided by a person-centered perspective and utilizing latent profile analysis, this study identified…

Transverse Diffusivity of Cerebral Parenchyma Predicts Visual Tracking Performance in Relapsing-Remitting Multiple Sclerosis

ERIC Educational Resources Information Center

Warlop, Nele P.; Achten, Eric; Fieremans, Els; Debruyne, Jan; Vingerhoets, Guy

2009-01-01

This study investigated the relation between cerebral damage related to multiple sclerosis (MS) and cognitive decline as determined by two classical mental tracking tests. Cerebral damage in 15 relapsing-remitting MS patients was measured by diffusion tensor imaging (DTI). Fractional anisotropy, longitudinal and transverse diffusivity were defined…

Scaling of charged particle production in d+Au collisions at √(sNN)=200GeV

NASA Astrophysics Data System (ADS)

Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

2005-09-01

The measured pseudorapidity distributions of primary charged particles over a wide pseudorapidity range of |η|≤5.4 and integrated charged particle multiplicities in d+Au collisions at √(sNN)=200GeV are presented as a function of collision centrality. The longitudinal features of d+Au collisions at √(sNN)=200GeV are found to be very similar to those seen in p+A collisions at lower energies. The total multiplicity of charged particles is found to scale with the total number of participants according to NdAuch=1/2Nppch, and the energy dependence of the density of charged particles produced in the fragmentation region exhibits extended longitudinal scaling.

Acoustic Longitudinal Field NIF Optic Feature Detection Map Using Time-Reversal & MUSIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehman, S K

2006-02-09

We developed an ultrasonic longitudinal field time-reversal and MUltiple SIgnal Classification (MUSIC) based detection algorithm for identifying and mapping flaws in fused silica NIF optics. The algorithm requires a fully multistatic data set, that is one with multiple, independently operated, spatially diverse transducers, each transmitter of which, in succession, launches a pulse into the optic and the scattered signal measured and recorded at every receiver. We have successfully localized engineered ''defects'' larger than 1 mm in an optic. We confirmed detection and localization of 3 mm and 5 mm features in experimental data, and a 0.5 mm in simulated datamore » with sufficiently high signal-to-noise ratio. We present the theory, experimental results, and simulated results.« less

Carotid endarterectomy: comparison of complications between transverse and longitudinal incision.

PubMed

Mendes, George A C; Zabramski, Joseph M; Elhadi, Ali M; Kalani, M Yashar S; Preul, Mark C; Nakaji, Peter; Spetzler, Robert F

2014-08-01

Cranial nerve injury (CNI) is the most common neurological complication associated with carotid endarterectomy (CEA). Some authors postulate that the transverse skin incision leads to increased risk of CNI. We compared the incidence of CNI associated with the transverse and longitudinal skin incisions in a high-volume cerebrovascular center. We reviewed the charts of 226 consecutive patients who underwent CEAs between January 2007 and August 2009. Pre- and postoperative standardized neurological evaluations were performed by faculty neurologists and neurosurgeons. One hundred sixty nine of 226 (75%) CEAs were performed with the use of a transverse incision. The longitudinal incision was generally reserved for patients with a high-riding carotid bifurcation. Mean patient age was 69 years (range, 45-91 years); 62% were men; 59% of patients were symptomatic and had high-grade stenosis (70%-99%). CNI occurred in 8 cases (3.5%): 5 (3%) in transverse and 3 (5.3%) with longitudinal incisions (P = .42). There were 2 marginal mandibular nerve injuries, 1 (0.6%) transverse and 1 longitudinal; 5 recurrent laryngeal nerve injuries, 4 transverse and 1 longitudinal; and 1 case of hypoglossal nerve injury associated with longitudinal incision. One hematoma was associated with CNI. All injuries were transient. Fourteen wound hematomas required surgical evacuation. The transverse skin incision for CEAs is not associated with an increased risk of CNI (P =.42). In this study, the incidence of CNI associated with the transverse incision was 3% (n = 5) vs 5% (n = 3) for longitudinal incisions. All CNIs were temporary.

Momentum loss in proton-nucleus and nucleus-nucleus collisions

NASA Technical Reports Server (NTRS)

Khan, Ferdous; Townsend, Lawrence W.

1993-01-01

An optical model description, based on multiple scattering theory, of longitudinal momentum loss in proton-nucleus and nucleus-nucleus collisions is presented. The crucial role of the imaginary component of the nucleon-nucleon transition matrix in accounting for longitudinal momentum transfer is demonstrated. Results obtained with this model are compared with Intranuclear Cascade (INC) calculations, as well as with predictions from Vlasov-Uehling-Uhlenbeck (VUU) and quantum molecular dynamics (QMD) simulations. Comparisons are also made with experimental data where available. These indicate that the present model is adequate to account for longitudinal momentum transfer in both proton-nucleus and nucleus-nucleus collisions over a wide range of energies.

Individual and Area-Based Socioeconomic Factors Associated With Dementia Incidence in England: Evidence From a 12-Year Follow-up in the English Longitudinal Study of Ageing.

PubMed

Cadar, Dorina; Lassale, Camille; Davies, Hilary; Llewellyn, David J; Batty, G David; Steptoe, Andrew

2018-05-16

Lower educational attainment is associated with a higher risk of dementia. However, less clear is the extent to which other socioeconomic markers contribute to dementia risk. To examine the relationship of education, wealth, and area-based deprivation with the incidence of dementia over the last decade in England and investigate differences between people born in different periods. Data from the English Longitudinal Study of Ageing, a prospective cohort study that is representative of the English population, were used to investigate the associations between markers of socioeconomic status (wealth quintiles and the index of multiple deprivation) and dementia incidence. To investigate outcomes associated with age cohorts, 2 independent groups were derived using a median split (born between 1902-1925 and 1926-1943) . Dementia as determined by physician diagnosis and the Informant Questionnaire on Cognitive Decline in the Elderly. A total of 6220 individuals aged 65 years and older enrolled in the study (median [interquartile range] age at baseline, 73.2 [68.1-78.3] years; 3410 [54.8%] female). Of these, 463 individuals (7.4%) had new cases of dementia ascertained in the 12 years between 2002-2003 and 2014-2015. The hazard of developing dementia was 1.68 times higher (hazard ratio [HR] = 1.68 [95% CI, 1.05-2.86]) for those in the lowest wealth quintile compared with those in the highest quintile, independent of education, index of multiple deprivation, and health indicators. Higher hazards were also observed for those in the second-highest quintile of index of multiple deprivation (HR = 1.62 [95% CI, 1.06-2.46]) compared with those in the lowest (least deprived) quintile. In an English nationally representative sample, the incidence of dementia appeared to be socioeconomically patterned primarily by the level of wealth. This association was somewhat stronger for participants born in later years.

Longitudinal Deformation of Distal Edge in a New-Generation Stent Caused by Guidewire Entrapment

PubMed Central

Taleb, Adam; Parikh, Gaurav

2018-01-01

Longitudinal stent deformation, described in some older stent geometries, prompted design modifications such as reinforcing struts on the proximal end. However, distal edges of stents—also subject to longitudinal force—have not been reinforced. We report a case of guidewire entrapment that deformed the distal edge of a new-generation stent during percutaneous coronary intervention, and we describe our efforts to restore the stent to its initial length. This case highlights the risk of manipulating equipment beyond the position of a newly deployed stent, the ongoing potential for deformation of distal edges in newer stent platforms, and the advisability of treating distal lesions before proximal ones. PMID:29556153

CBCT volumetric coverage extension using a pair of complementary circular scans with complementary kV detector lateral and longitudinal offsets

NASA Astrophysics Data System (ADS)

Yang, Deshan; Li, H. Harold; Goddu, S. Murty; Tan, Jun

2014-10-01

Onboard cone-beam CT (CBCT) has been widely used in image guided radiation therapy. However, the longitudinal coverage is only 15.5 cm in the pelvis scan mode. As a result, a single CBCT scan cannot cover the planning target volume in the longitudinal direction for over 80% of the patients. The common approach is to use double- or multiple-circular scans and then combine multiple CBCT volumes after reconstruction. However it raises concerns regarding doubled imaging dose at the imaging beam junctions due to beam divergence. In this work, we present a new method, DSCS (Dual Scan with Complementary Shifts), to address the CBCT coverage problem using a pair of complementary circular scans. In DSCS, two circular scans were performed at 39.5 cm apart longitudinally. In the superior scan, the detector panel was offset by 16 cm to the left, 15 cm to the inferior. In the inferior scan, the detector panel was shifted 16 cm to the right and 15 cm to the superior. The effective imaging volume is 39.5 cm longitudinally with a 45 cm lateral field-of-view (FOV). Half beam blocks were used to confine the imaging radiation inside the volume of interest. A new image reconstruction algorithm was developed, based on the Feldkamp-Davis-Kress cone-beam CT reconstruction algorithm, to support the DSCS scanning geometry. Digital phantom simulations were performed to demonstrate the feasibility of DSCS. Physical phantom studies were performed using an anthropomorphic phantom on a commercial onboard CBCT system. With basic scattering corrections, the reconstruction results were acceptable. Other issues, including the discrepancy in couch vertical at different couch longitudinal positions, and the inaccuracy in couch table longitudinal movement, were manually corrected during the reconstruction process. In conclusion, the phantom studies showed that, using DSCS, a 39.5 cm longitudinal coverage with a 45 cm FOV was accomplished. The efficiency of imaging dose usage was near 100%. This proposed method could be potentially useful for image guidance and subsequent treatment plan adaptation.

TH-C-19A-01: Analytic Design Method to Make a 2D Planar, Segmented Ion Chamber Water-Equivalent for Proton Dose Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, W; Hollebeek, R; Teo, B

2014-06-15

Purpose: Quality Assurance (QA) measurements of proton therapy fields must accurately measure steep longitudinal dose gradients as well as characterize the dose distribution laterally. Currently, available devices for two-dimensional field measurements perturb the dose distribution such that routine QA measurements performed at multiple depths require multiple field deliveries and are time consuming. Methods: A design procedure for a two-dimensional detector array is introduced whereby the proton energy loss and scatter are adjusted so that the downstream dose distribution is maintained to be equivalent to that which would occur in uniform water. Starting with the design for an existing, functional two-dimensionalmore » segmented ion chamber prototype, a compensating material is introduced downstream of the detector to simultaneously equate the energy loss and lateral scatter in the detector assembly to the values in water. An analytic formalism and procedure is demonstrated to calculate the properties of the compensating material in the general case of multiple layers of arbitrary material. The resulting design is validated with Monte Carlo simulations. Results: With respect to the specific prototype design considered, the results indicate that a graphite compensating layer of the proper dimensions can yield proton beam range perturbation less than 0.1mm and beam sigma perturbation less than 2% across the energy range of therapeutic proton beams. Conclusion: We have shown that, for a 2D gas-filled detector array, a graphite-compensating layer can balance the energy loss and multiple Coulomb scattering relative to uniform water. We have demonstrated an analytic formalism and procedure to determine a compensating material in the general case of multiple layers of arbitrary material. This work was supported by the US Army Medical Research and Materiel Command under Contract Agreement No. DAMD17-W81XWH-04-2-0022. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the US Army.« less

Results of endocapsular phacofracture debulking of hard cataracts

PubMed Central

Davison, James A

2015-01-01

Purpose/aim of the study To present a phacoemulsification technique for hard cataracts and compare postoperative results using two different ultrasonic tip motions during quadrant removal. Materials and methods A phacoemulsification technique which employs in situ fracture and endocapsular debulking for hard cataracts is presented. The prospective study included 56 consecutive cases of hard cataract (LOCS III NC [Lens Opacification Classification System III, nuclear color], average 4.26), which were operated using the Infiniti machine and the Partial Kelman tip. Longitudinal tip movement was used for sculpting for all cases which were randomized to receive longitudinal or torsional/interjected longitudinal (Intelligent Phaco [IP]) strategies for quadrant removal. Measurements included cumulative dissipated energy (CDE), 3 months postoperative surgically induced astigmatism (SIA), and corneal endothelial cell density (ECD) losses. Results No complications were recorded in any of the cases. Respective overall and longitudinal vs IP means were as follows: CDE, 51.6±15.6 and 55.7±15.5 vs 48.6±15.1; SIA, 0.36±0.2 D and 0.4±0.2 D vs 0.3±0.2 D; and mean ECD loss, 4.1%±10.8% and 5.9%±13.4% vs 2.7%±7.8%. The differences between longitudinal and IP were not significant for any of the three categories. Conclusion The endocapsular phacofracture debulking technique is safe and effective for phacoemulsification of hard cataracts using longitudinal or torsional IP strategies for quadrant removal with the Infiniti machine and Partial Kelman tip. PMID:26203213

Modeling Longitudinal Data Containing Non-Normal Within Subject Errors

NASA Technical Reports Server (NTRS)

Feiveson, Alan; Glenn, Nancy L.

2013-01-01

The mission of the National Aeronautics and Space Administration’s (NASA) human research program is to advance safe human spaceflight. This involves conducting experiments, collecting data, and analyzing data. The data are longitudinal and result from a relatively few number of subjects; typically 10 – 20. A longitudinal study refers to an investigation where participant outcomes and possibly treatments are collected at multiple follow-up times. Standard statistical designs such as mean regression with random effects and mixed–effects regression are inadequate for such data because the population is typically not approximately normally distributed. Hence, more advanced data analysis methods are necessary. This research focuses on four such methods for longitudinal data analysis: the recently proposed linear quantile mixed models (lqmm) by Geraci and Bottai (2013), quantile regression, multilevel mixed–effects linear regression, and robust regression. This research also provides computational algorithms for longitudinal data that scientists can directly use for human spaceflight and other longitudinal data applications, then presents statistical evidence that verifies which method is best for specific situations. This advances the study of longitudinal data in a broad range of applications including applications in the sciences, technology, engineering and mathematics fields.

Methodology to Estimate the Longitudinal Average Attributable Fraction of Guideline-recommended Medications for Death in Older Adults With Multiple Chronic Conditions

PubMed Central

Zhan, Yilei; Cohen, Andrew B.; Tinetti, Mary E.; Trentalange, Mark; McAvay, Gail

2016-01-01

Background: Persons with multiple chronic conditions receive multiple guideline-recommended medications to improve outcomes such as mortality. Our objective was to estimate the longitudinal average attributable fraction for 3-year survival of medications for cardiovascular conditions in persons with multiple chronic conditions and to determine whether heterogeneity occurred by age. Methods: Medicare Current Beneficiary Survey participants (N = 8,578) with two or more chronic conditions, enrolled from 2005 to 2009 with follow-up through 2011, were analyzed. We calculated the longitudinal extension of the average attributable fraction for oral medications (beta blockers, renin–angiotensin system blockers, and thiazide diuretics) indicated for cardiovascular conditions (atrial fibrillation, coronary artery disease, heart failure, and hypertension), on survival adjusted for 18 participant characteristics. Models stratified by age (≤80 and >80 years) were analyzed to determine heterogeneity of both cardiovascular conditions and medications. Results: Heart failure had the greatest average attributable fraction (39%) for mortality. The fractional contributions of beta blockers, renin–angiotensin system blockers, and thiazides to improve survival were 10.4%, 9.3%, and 7.2% respectively. In age-stratified models, of these medications thiazides had a significant contribution to survival only for those aged 80 years or younger. The effects of the remaining medications were similar in both age strata. Conclusions: Most cardiovascular medications were attributed independently to survival. The two cardiovascular conditions contributing independently to death were heart failure and atrial fibrillation. The medication effects were similar by age except for thiazides that had a significant contribution to survival in persons younger than 80 years. PMID:26748093

A Bayesian Semiparametric Approach for Incorporating Longitudinal Information on Exposure History for Inference in Case-Control Studies

PubMed Central

Bhadra, Dhiman; Daniels, Michael J.; Kim, Sungduk; Ghosh, Malay; Mukherjee, Bhramar

2014-01-01

In a typical case-control study, exposure information is collected at a single time-point for the cases and controls. However, case-control studies are often embedded in existing cohort studies containing a wealth of longitudinal exposure history on the participants. Recent medical studies have indicated that incorporating past exposure history, or a constructed summary measure of cumulative exposure derived from the past exposure history, when available, may lead to more precise and clinically meaningful estimates of the disease risk. In this paper, we propose a flexible Bayesian semiparametric approach to model the longitudinal exposure profiles of the cases and controls and then use measures of cumulative exposure based on a weighted integral of this trajectory in the final disease risk model. The estimation is done via a joint likelihood. In the construction of the cumulative exposure summary, we introduce an influence function, a smooth function of time to characterize the association pattern of the exposure profile on the disease status with different time windows potentially having differential influence/weights. This enables us to analyze how the present disease status of a subject is influenced by his/her past exposure history conditional on the current ones. The joint likelihood formulation allows us to properly account for uncertainties associated with both stages of the estimation process in an integrated manner. Analysis is carried out in a hierarchical Bayesian framework using Reversible jump Markov chain Monte Carlo (RJMCMC) algorithms. The proposed methodology is motivated by, and applied to a case-control study of prostate cancer where longitudinal biomarker information is available for the cases and controls. PMID:22313248

Chronic periodontitis with multiple risk factor syndrome: a case report.

PubMed

Shimoe, Masayuki; Yamamoto, Tadashi; Iwamoto, Yoshihiro; Shiomi, Nobuyuki; Maeda, Hiroshi; Nishimura, Fusanori; Takashiba, Shogo

2011-07-01

Multiple risk factor syndrome is a clustering of cardiovascular risk factors, such as diabetes, dyslipidemia, hypertension, and obesity associated epidemiologically with insulin resistance. This report describes the clinical course of a patient suffering from severe periodontitis with multiple risk factor syndrome, and discusses the association between periodontal infection and systemic health. The patient had a history of type 2 diabetes, dyslipidemia, and hypertension for over 10 years. At baseline, her hemoglobin A1 c was 8.1%. However, she had no diabetic complications except periodontitis. The IgG antibody titers against Porphyromonas gingivalis FDC 381 and SU63 were elevated above the mean of healthy subjects +2 standard deviations. Intensive periodontal treatment, including periodontal surgery, was performed to reduce periodontal infection and bacteremia. Her systemic and periodontal conditions were evaluated longitudinally for 10 years. Following periodontal treatment, antibody titers against Porphyromonas gingivalis and hemoglobin A1c values were significantly improved. The other clinical data and medication for her systemic condition also remained stable during supportive periodontal therapy. However, she developed myocardial infarction, and showed continuous deterioration of hemoglobin A1 c level and periodontitis. The long-term clustering of risk factors, such as diabetes, dyslipidemia, hypertension, and periodontitis, are associated with the development of myocardial infarction. Treatment of systemic conditions in combination with comprehensive periodontal treatment is important in management of patients with multiple risk factor syndrome.

Bayesian Covariate Selection in Mixed-Effects Models For Longitudinal Shape Analysis

PubMed Central

Muralidharan, Prasanna; Fishbaugh, James; Kim, Eun Young; Johnson, Hans J.; Paulsen, Jane S.; Gerig, Guido; Fletcher, P. Thomas

2016-01-01

The goal of longitudinal shape analysis is to understand how anatomical shape changes over time, in response to biological processes, including growth, aging, or disease. In many imaging studies, it is also critical to understand how these shape changes are affected by other factors, such as sex, disease diagnosis, IQ, etc. Current approaches to longitudinal shape analysis have focused on modeling age-related shape changes, but have not included the ability to handle covariates. In this paper, we present a novel Bayesian mixed-effects shape model that incorporates simultaneous relationships between longitudinal shape data and multiple predictors or covariates to the model. Moreover, we place an Automatic Relevance Determination (ARD) prior on the parameters, that lets us automatically select which covariates are most relevant to the model based on observed data. We evaluate our proposed model and inference procedure on a longitudinal study of Huntington's disease from PREDICT-HD. We first show the utility of the ARD prior for model selection in a univariate modeling of striatal volume, and next we apply the full high-dimensional longitudinal shape model to putamen shapes. PMID:28090246

I and Us: A Longitudinal Study on the Interplay of Personal and Social Identity in Adolescence.

PubMed

Albarello, Flavia; Crocetti, Elisabetta; Rubini, Monica

2018-04-01

The development of personal and social identity is crucial in adolescence. On the one hand, adolescents face the task of forming and consolidating their personal identity in multiple domains, with educational and interpersonal domains particularly salient. On the other hand, they enlarge their social horizon and increasingly define themselves as members of multiple peer groups, such as groups of classmates and friends met outside school. There is however a lack of integrative research on the interplay among and between personal and social identity processes. Hence the purpose of this study was threefold. First, we examined how personal identity processes in the educational and interpersonal domains are associated longitudinally. Second, we investigated to what extent social identifications with classmates and with the group of friends are associated over time. Third, with an original approach we examined the longitudinal interplay between personal and social identity processes, to connect theoretical contributions that have so far proceeded largely in parallel. Participants were 304 adolescents (61.84% female, M age  = 17.49) involved in a three-wave longitudinal study. We found that (a) the ways in which adolescents develop their identity in the educational and interpersonal domains become more closely intertwined over time; (b) identifications with classmates and with the group of friends are interconnected; and (c) personal and social identity processes are associated both concurrently and longitudinally, with most cross-lagged effects showing that social identifications influence personal identity formation and consolidation in the interpersonal identity domain. Theoretical implications are discussed.

Longitudinal relationships among posturography and gait measures in multiple sclerosis.

PubMed

Fritz, Nora E; Newsome, Scott D; Eloyan, Ani; Marasigan, Rhul Evans R; Calabresi, Peter A; Zackowski, Kathleen M

2015-05-19

Gait and balance dysfunction frequently occurs early in the multiple sclerosis (MS) disease course. Hence, we sought to determine the longitudinal relationships among quantitative measures of gait and balance in individuals with MS. Fifty-seven ambulatory individuals with MS (28 relapsing-remitting, 29 progressive) were evaluated using posturography, quantitative sensorimotor and gait measures, and overall MS disability with the Expanded Disability Status Scale at each session. Our cohort's age was 45.8 ± 10.4 years (mean ± SD), follow-up time 32.8 ± 15.4 months, median Expanded Disability Status Scale score 3.5, and 56% were women. Poorer performance on balance measures was related to slower walking velocity. Two posturography measures, the anterior-posterior sway and sway during static eyes open, feet apart conditions, were significant contributors to walk velocity over time (approximate R(2) = 0.95), such that poorer performance on the posturography measures was related to slower walking velocity. Similarly, the anterior-posterior sway and sway during static eyes closed, feet together conditions were also significant contributors to the Timed 25-Foot Walk performance over time (approximate R(2) = 0.83). This longitudinal cohort study establishes a strong relationship between clinical gait measures and posturography. The data show that increases in static posturography and reductions in dynamic posturography are associated with a decline in walk velocity and Timed 25-Foot Walk performance over time. Furthermore, longitudinal balance measures predict future walking performance. Quantitative walking and balance measures are important additions to clinical testing to explore longitudinal change and understand fall risk in this progressive disease population. © 2015 American Academy of Neurology.

A Longitudinal Field Study Comparing a Multiplicative and an Additive Model of Motivation and Ability. Technical Report No. 11.

ERIC Educational Resources Information Center

Barrett, Gerald V.; And Others

The relative contribution of motivation to ability measures in predicting performance criteria of sales personnel from successive fiscal periods was investigated. In this context, the merits of a multiplicative and additive combination of motivation and ability measures were examined. The relationship between satisfaction and motivation and…

A Collaboratively Designed Child Mental Health Service Model: Multiple Family Groups for Urban Children with Conduct Difficulties

ERIC Educational Resources Information Center

McKay, Mary M.; Gopalan, Geetha; Franco, Lydia; Dean-Assael, Kara; Chacko, Anil; Jackson, Jerrold M.; Fuss, Ashley

2011-01-01

This article presents preliminary outcomes associated with an experimental, longitudinal study of a Multiple Family Group (MFG) service delivery approach set within 13 urban outpatient clinics serving children and their families living in inner-city, primarily African American and Latino communities. Specifically, this article focuses on parent…

Effects of Multiple Context and Cumulative Stress on Urban Children's Adjustment in Elementary School

ERIC Educational Resources Information Center

Morales, Julie R.; Guerra, Nancy G.

2006-01-01

Using longitudinal data collected over 2 years on a sample of 2,745 urban elementary school children (1st-6th graders, ages 6-11 years) from economically disadvantaged communities, effects of stressful experiences within 3 contexts (school, family, neighborhood), cumulative stress, and multiple context stress on 3 indices of children's adjustment…

The impact of different strategies to handle missing data on both precision and bias in a drug safety study: a multidatabase multinational population-based cohort study

PubMed Central

Martín-Merino, Elisa; Calderón-Larrañaga, Amaia; Hawley, Samuel; Poblador-Plou, Beatriz; Llorente-García, Ana; Petersen, Irene; Prieto-Alhambra, Daniel

2018-01-01

Background Missing data are often an issue in electronic medical records (EMRs) research. However, there are many ways that people deal with missing data in drug safety studies. Aim To compare the risk estimates resulting from different strategies for the handling of missing data in the study of venous thromboembolism (VTE) risk associated with antiosteoporotic medications (AOM). Methods New users of AOM (alendronic acid, other bisphosphonates, strontium ranelate, selective estrogen receptor modulators, teriparatide, or denosumab) aged ≥50 years during 1998–2014 were identified in two Spanish (the Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria [BIFAP] and EpiChron cohort) and one UK (Clinical Practice Research Datalink [CPRD]) EMR. Hazard ratios (HRs) according to AOM (with alendronic acid as reference) were calculated adjusting for VTE risk factors, body mass index (that was missing in 61% of patients included in the three databases), and smoking (that was missing in 23% of patients) in the year of AOM therapy initiation. HRs and standard errors obtained using cross-sectional multiple imputation (MI) (reference method) were compared to complete case (CC) analysis – using only patients with complete data – and longitudinal MI – adding to the cross-sectional MI model the body mass index/smoking values as recorded in the year before and after therapy initiation. Results Overall, 422/95,057 (0.4%), 19/12,688 (0.1%), and 2,051/161,202 (1.3%) VTE cases/participants were seen in BIFAP, EpiChron, and CPRD, respectively. HRs moved from 100.00% underestimation to 40.31% overestimation in CC compared with cross-sectional MI, while longitudinal MI methods provided similar risk estimates compared with cross-sectional MI. Precision for HR improved in cross-sectional MI versus CC by up to 160.28%, while longitudinal MI improved precision (compared with cross-sectional) only minimally (up to 0.80%). Conclusion CC may substantially affect relative risk estimation in EMR-based drug safety studies, since missing data are not often completely at random. Little improvement was seen in these data in terms of power with the inclusion of longitudinal MI compared with cross-sectional MI. The strategy for handling missing data in drug safety studies can have a large impact on both risk estimates and precision.

The impact of different strategies to handle missing data on both precision and bias in a drug safety study: a multidatabase multinational population-based cohort study.

PubMed

Martín-Merino, Elisa; Calderón-Larrañaga, Amaia; Hawley, Samuel; Poblador-Plou, Beatriz; Llorente-García, Ana; Petersen, Irene; Prieto-Alhambra, Daniel

2018-01-01

Missing data are often an issue in electronic medical records (EMRs) research. However, there are many ways that people deal with missing data in drug safety studies. To compare the risk estimates resulting from different strategies for the handling of missing data in the study of venous thromboembolism (VTE) risk associated with antiosteoporotic medications (AOM). New users of AOM (alendronic acid, other bisphosphonates, strontium ranelate, selective estrogen receptor modulators, teriparatide, or denosumab) aged ≥50 years during 1998-2014 were identified in two Spanish (the Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria [BIFAP] and EpiChron cohort) and one UK (Clinical Practice Research Datalink [CPRD]) EMR. Hazard ratios (HRs) according to AOM (with alendronic acid as reference) were calculated adjusting for VTE risk factors, body mass index (that was missing in 61% of patients included in the three databases), and smoking (that was missing in 23% of patients) in the year of AOM therapy initiation. HRs and standard errors obtained using cross-sectional multiple imputation (MI) (reference method) were compared to complete case (CC) analysis - using only patients with complete data - and longitudinal MI - adding to the cross-sectional MI model the body mass index/smoking values as recorded in the year before and after therapy initiation. Overall, 422/95,057 (0.4%), 19/12,688 (0.1%), and 2,051/161,202 (1.3%) VTE cases/participants were seen in BIFAP, EpiChron, and CPRD, respectively. HRs moved from 100.00% underestimation to 40.31% overestimation in CC compared with cross-sectional MI, while longitudinal MI methods provided similar risk estimates compared with cross-sectional MI. Precision for HR improved in cross-sectional MI versus CC by up to 160.28%, while longitudinal MI improved precision (compared with cross-sectional) only minimally (up to 0.80%). CC may substantially affect relative risk estimation in EMR-based drug safety studies, since missing data are not often completely at random. Little improvement was seen in these data in terms of power with the inclusion of longitudinal MI compared with cross-sectional MI. The strategy for handling missing data in drug safety studies can have a large impact on both risk estimates and precision.

Pooling Data from Multiple Longitudinal Studies: The Role of Item Response Theory in Integrative Data Analysis

PubMed Central

Curran, Patrick J.; Hussong, Andrea M.; Cai, Li; Huang, Wenjing; Chassin, Laurie; Sher, Kenneth J.; Zucker, Robert A.

2010-01-01

There are a number of significant challenges encountered when studying development over an extended period of time including subject attrition, changing measurement structures across group and developmental period, and the need to invest substantial time and money. Integrative data analysis is an emerging set of methodologies that overcomes many of the challenges of single sample designs through the pooling of data drawn from multiple existing developmental studies. This approach is characterized by a host of advantages, but this also introduces several new complexities that must be addressed prior to broad adoption by developmental researchers. In this paper we focus on methods for fitting measurement models and creating scale scores using data drawn from multiple longitudinal studies. We present findings from the analysis of repeated measures of internalizing symptomatology that were pooled from three existing developmental studies. We describe and demonstrate each step in the analysis and we conclude with a discussion of potential limitations and directions for future research. PMID:18331129

Higher Education and Religious Liberalization among Young Adults*

PubMed Central

Mayrl, Damon; Uecker, Jeremy E.

2012-01-01

Going to college has long been assumed to liberalize students’ religious beliefs. Using longitudinal data from the National Survey of Youth and Religion, we compare change in the content of religious beliefs of those who do and do not attend college. We find that, in general, college students are no more likely to develop liberal religious beliefs than nonstudents. In some cases, collegians actually appear more likely to retain their initial beliefs. Change in religious beliefs appears instead to be more strongly associated with network effects. These findings indicate that college’s effect on students’ religious beliefs is both weak and fragmented, and suggest that the multiplicity of social worlds on college campuses may help to sustain religious beliefs as well as religious practice and commitment. PMID:22665942

Aerodynamic preliminary analysis system. Part 2: User's manual and program description

NASA Technical Reports Server (NTRS)

Divan, P.; Dunn, K.; Kojima, J.

1978-01-01

A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies or noncircular contour are analyzed. Longitudinal and lateral-directional static and rotary derivative solutions are generated. The analysis is implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

Positive and negative effective mass of classical particles in oscillatory and static fields.

PubMed

Dodin, I Y; Fisch, N J

2008-03-01

A classical particle oscillating in an arbitrary high-frequency or static field effectively exhibits a modified rest mass m(eff) derived from the particle averaged Lagrangian. Relativistic ponderomotive and diamagnetic forces, as well as magnetic drifts, are obtained from the m(eff) dependence on the guiding center location and velocity. The effective mass is not necessarily positive and can result in backward acceleration when an additional perturbation force is applied. As an example, adiabatic dynamics with m||>0 and m||<0 is demonstrated for a wave-driven particle along a dc magnetic field, m|| being the effective longitudinal mass derived from m(eff). Multiple energy states are realized in this case, yielding up to three branches of m|| for a given magnetic moment and parallel velocity.

Peer Status and Victimization as Possible Reinforcements of Adolescent Girls’ and Boys’ Weight-Related Behaviors and Cognitions

PubMed Central

Prinstein, Mitchell J.

2010-01-01

Objective Reciprocal longitudinal associations among weight-related behaviors and cognitions and peer relations constructs were examined among adolescent males and females. Methods Participants included 576 adolescents aged 10–14 years, in grades 6–8. Measures assessed body dissatisfaction, negative weight-related cognitions, weight management behaviors, muscle-gaining behaviors, body mass index (BMI), likeability, popularity, and victimization at two time points, approximately 11 months apart. Multiple group path analyses were conducted to examine the reciprocal longitudinal associations between the peer relations constructs and weight-related behaviors and cognitions, controlling for participants’ Time 1 BMI, pubertal development, and age. Results Higher levels of body dissatisfaction were associated longitudinally with decreases in popularity. Higher popularity and lower likeability each were associated longitudinally with increases in negative body-related cognitions. Higher popularity was associated longitudinally with muscle-gaining behaviors for boys. Conclusions Findings suggest highly popular and disliked adolescents may be at greater risk of weight-related behaviors and cognitions than other adolescents. PMID:19667053

Accounting for dropout reason in longitudinal studies with nonignorable dropout.

PubMed

Moore, Camille M; MaWhinney, Samantha; Forster, Jeri E; Carlson, Nichole E; Allshouse, Amanda; Wang, Xinshuo; Routy, Jean-Pierre; Conway, Brian; Connick, Elizabeth

2017-08-01

Dropout is a common problem in longitudinal cohort studies and clinical trials, often raising concerns of nonignorable dropout. Selection, frailty, and mixture models have been proposed to account for potentially nonignorable missingness by relating the longitudinal outcome to time of dropout. In addition, many longitudinal studies encounter multiple types of missing data or reasons for dropout, such as loss to follow-up, disease progression, treatment modifications and death. When clinically distinct dropout reasons are present, it may be preferable to control for both dropout reason and time to gain additional clinical insights. This may be especially interesting when the dropout reason and dropout times differ by the primary exposure variable. We extend a semi-parametric varying-coefficient method for nonignorable dropout to accommodate dropout reason. We apply our method to untreated HIV-infected subjects recruited to the Acute Infection and Early Disease Research Program HIV cohort and compare longitudinal CD4 + T cell count in injection drug users to nonusers with two dropout reasons: anti-retroviral treatment initiation and loss to follow-up.

Preservation of person-specific knowledge in semantic memory disorder: a longitudinal investigation in two cases of dementia.

PubMed

Haslam, Catherine; Sabah, Mazen

2013-03-01

The double dissociation involving person-specific and general semantic knowledge is supported by numerous patient studies, though cases with preservation of the former are few. In this paper, we report longitudinal data from two cases. Their knowledge in both domains was preserved at the start of the investigation, but progressive deterioration was primarily observed on tests of general semantics. These data strengthen the evidence-base for preservation of person-specific knowledge in semantic memory disorder, and support its separate representation from object knowledge. © 2012 The British Psychological Society.

Intraoperative performance and postoperative outcome comparison of longitudinal, torsional, and transversal phacoemulsification machines.

PubMed

Christakis, Panos G; Braga-Mele, Rosa M

2012-02-01

To compare the intraoperative performance and postoperative outcomes of 3 phacoemulsification machines that use different modes. Kensington Eye Institute, Toronto, Ontario, Canada. Comparative case series. This chart and video review comprised consecutive eligible patients who had phacoemulsification by the same surgeon using a Whitestar Signature Ellips-FX (transversal), Infiniti-Ozil-IP (torsional), or Stellaris (longitudinal) machine. The review included 98 patients. Baseline characteristics in the groups were similar; the mean nuclear sclerosis grade was 2.0 ± 0.8. There were no significant intraoperative complications. The torsional machine averaged less phacoemulsification needle time (83 ± 33 seconds) than the transversal (99 ± 40 seconds; P=.21) or longitudinal (110 ± 45 seconds; P=.02) machines; the difference was accentuated in cases with high-grade nuclear sclerosis. The torsional machine had less chatter and better followability than the transversal or longitudinal machines (P<.001). The torsional and longitudinal machines had better anterior chamber stability than the transversal machine (P<.001). Postoperatively, the torsional machine yielded less central corneal edema than the transversal (P<.001) and longitudinal (P=.04) machines, corresponding to a smaller increase in mean corneal thickness (torsional 5%, transversal 10%, longitudinal 12%; P=.04). Also, the torsional machine had better 1-day postoperative visual acuities (P<.001). All 3 phacoemulsification machines were effective with no significant intraoperative complications. The torsional machine outperformed the transversal and longitudinal machines, with a lower mean needle time, less chatter, and improved followability. This corresponded to less corneal edema 1 day postoperatively and better visual acuity. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Increased cerebrospinal fluid albumin and immunoglobulin A fractions forecast cortical atrophy and longitudinal functional deterioration in relapsing-remitting multiple sclerosis.

PubMed

Kroth, Julia; Ciolac, Dumitru; Fleischer, Vinzenz; Koirala, Nabin; Krämer, Julia; Muthuraman, Muthuraman; Luessi, Felix; Bittner, Stefan; Gonzalez-Escamilla, Gabriel; Zipp, Frauke; Meuth, Sven G; Groppa, Sergiu

2017-12-01

Currently, no unequivocal predictors of disease evolution exist in patients with multiple sclerosis (MS). Cortical atrophy measurements are, however, closely associated with cumulative disability. Here, we aim to forecast longitudinal magnetic resonance imaging (MRI)-driven cortical atrophy and clinical disability from cerebrospinal fluid (CSF) markers. We analyzed CSF fractions of albumin and immunoglobulins (Ig) A, G, and M and their CSF to serum quotients. Widespread atrophy was highly associated with increased baseline CSF concentrations and quotients of albumin and IgA. Patients with increased CSF IgA and CSF IgM showed higher functional disability at follow-up. CSF markers of blood-brain barrier integrity and specific immune response forecast emerging gray matter pathology and disease progression in MS.

On Latent Growth Models for Composites and Their Constituents.

PubMed

Hancock, Gregory R; Mao, Xiulin; Kher, Hemant

2013-09-01

Over the last decade and a half, latent growth modeling has become an extremely popular and versatile technique for evaluating longitudinal change and its determinants. Most common among the models applied are those for a single measured variable over time. This model has been extended in a variety of ways, most relevant for the current work being the multidomain and the second-order latent growth models. Whereas the former allows for growth function characteristics to be modeled for multiple outcomes simultaneously, with the degree of growth characteristics' relations assessed within the model (e.g., cross-domain slope factor correlations), the latter models growth in latent outcomes, each of which has effect indicators repeated over time. But what if one has an outcome that is believed to be formative relative to its indicator variables rather than latent? In this case, where the outcome is a composite of multiple constituents, modeling change over time is less straightforward. This article provides analytical and applied details for simultaneously modeling growth in composites and their constituent elements, including a real data example using a general computer self-efficacy questionnaire.

Lesion registration for longitudinal disease tracking in an imaging informatics-based multiple sclerosis eFolder

NASA Astrophysics Data System (ADS)

Ma, Kevin; Liu, Joseph; Zhang, Xuejun; Lerner, Alex; Shiroishi, Mark; Amezcua, Lilyana; Liu, Brent

2016-03-01

We have designed and developed a multiple sclerosis eFolder system for patient data storage, image viewing, and automatic lesion quantification results stored in DICOM-SR format. The web-based system aims to be integrated in DICOM-compliant clinical and research environments to aid clinicians in patient treatments and data analysis. The system needs to quantify lesion volumes, identify and register lesion locations to track shifts in volume and quantity of lesions in a longitudinal study. In order to perform lesion registration, we have developed a brain warping and normalizing methodology using Statistical Parametric Mapping (SPM) MATLAB toolkit for brain MRI. Patients' brain MR images are processed via SPM's normalization processes, and the brain images are analyzed and warped according to the tissue probability map. Lesion identification and contouring are completed by neuroradiologists, and lesion volume quantification is completed by the eFolder's CAD program. Lesion comparison results in longitudinal studies show key growth and active regions. The results display successful lesion registration and tracking over a longitudinal study. Lesion change results are graphically represented in the web-based user interface, and users are able to correlate patient progress and changes in the MRI images. The completed lesion and disease tracking tool would enable the eFolder to provide complete patient profiles, improve the efficiency of patient care, and perform comprehensive data analysis through an integrated imaging informatics system.

The Oporto mixed-longitudinal growth, health and performance study. Design, methods and baseline results.

PubMed

Souza, Michele Caroline de; Chaves, Raquel Nichele de; Dos Santos, Fernanda Karina; Gomes, Thayse Natacha Queiroz Ferreira; Santos, Daniel Vilhena E; Borges, Alessandra Silva; Pereira, Sara Isabel Sampaio; Forjaz, Cláudia Lúcia de Moraes; Eisenmann, Joey; Maia, José António Ribeiro

2017-02-01

Studies concerning child and adolescent growth, development, performance and health aimed at the multiple interactions amongst this complex set of variables are not common in the Portuguese speaking countries. The aim of this paper is to address the key ideas, methodology and design of the Oporto Growth, Health and Performance Study (OGHPS). The OGHPS is a multidisciplinary mixed-longitudinal study whose main purpose is to examine the multiple interactions among biological, environmental and lifestyle indicators that affect growth, development, health and performance of Portuguese adolescents aged 10-18 years old. This study briefly presents baseline results for growth, physical fitness and lifestyle behaviours for those participating in the cross-sectional sample (n ≈ 8000). Approximately 30% were over-fat or obese. On average, boys were more physically fit and active than girls. Few adolescents meet the guidelines for sleep duration (≈10%) and eating habits (16.2-24.8%), while 76-85% meet the recommended levels of moderate-to-vigorous physical activity. The OGHPS has an innovative approach due to its mixed-longitudinal design and the broad array of variables. Furthermore, subsequent analyses of the longitudinal data will enable a detailed exploration of important factors affecting the growth trajectories of health and performance variables and will also help to identify some of the most opportune times for interventions in terms of health behaviours.

Acquired Bilateral Longitudinal True Leukonychia in a 35-year-old Woman

PubMed Central

Mokhtari, Fatemeh; Mozafarpoor, Samaneh; Nouraei, Saeid; Nilforoushzadeh, Mohammad Ali

2016-01-01

Acquired bilateral longitudinal true leukonychia is a rare disorder. We present a case of a 35-year-old healthy woman presented with this unusual and rare manifestation. She mentioned a history of unprotected exposure to detergents and bleaching chemical agents. Considering her low zinc level, she was prescribed with zinc capsules and recommended to avoid chemical substances for 6 months. During bimonthly follow-up, her zinc level turned normal, and leukonychia subsequently disappeared. Bilateral longitudinal true leukonychia in the nails due to zinc deficiency and exposure to chemical substances has not been reported previously. Direct and indirect effects of chemical substances on matrix and the effect of zinc deficiency on healing process should be considered in these cases. PMID:27857831

Cervical intradural disc herniation.

PubMed

Iwamura, Y; Onari, K; Kondo, S; Inasaka, R; Horii, H

2001-03-15

A case report of anterior en bloc resected cervical intradural disc herniation and a review of the literature. To discuss the pathogenesis of cervical intradural disc herniation. Including this study case, only 17 cases of cervical intradural disc herniation have been reported. There have been few detailed reports concerning the pathogenesis of cervical intradural disc herniation. A cervical intradural disc herniation at C6-C7, with localized hypertrophy and segmentally ossified posterior longitudinal ligament, is reported in a 45-year-old man who had Brown-Sequard syndrome diagnosed on neurologic examination. Neuroradiologic, operative, and histologic findings, particularly the pathology of the anterior en bloc resected posterior vertebral portion of C6 and C7, were evaluated for discussion of the pathogenesis. Adhesion of dura mater and hypertrophic posterior longitudinal ligament was observed around a perforated portion of the herniated disc, and histologic study showed irregularity in fiber alignment accompanied by scattered inflammatory cell infiltration and hypertrophy in the posterior longitudinal ligament. The cervical intradural disc herniation was removed successfully and followed by C5-Th1 anterior interbody fusion with fibular strut graft. Neurologic recovery was complete except for minor residual sensory disturbance in the leg 7 years after the surgery. Cervical intradural disc herniation is an extremely rare condition. The pathogenesis remains obscure. Only 16 cases have been reported in the literature, and there has been little discussion concerning the local pathology of the herniated portion. The pathogenesis of the disease in the patient reported here was considered to be the adhesion and fragility of dura mater and posterior longitudinal ligament. This was caused by hypertrophy, with chronic inflammation and ossification of the posterior longitudinal ligament sustaining chronic mechanical irritation to the dura mater, leading to perforation of the herniated disc by an accidental force.

An opposite view data replacement approach for reducing artifacts due to metallic dental objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yazdi, Mehran; Lari, Meghdad Asadi; Bernier, Gaston

Purpose: To present a conceptually new method for metal artifact reduction (MAR) that can be used on patients with multiple objects within the scan plane that are also of small sized along the longitudinal (scanning) direction, such as dental fillings. Methods: The proposed algorithm, named opposite view replacement, achieves MAR by first detecting the projection data affected by metal objects and then replacing the affected projections by the corresponding opposite view projections, which are not affected by metal objects. The authors also applied a fading process to avoid producing any discontinuities in the boundary of the affected projection areas inmore » the sinogram. A skull phantom with and without a variety of dental metal inserts was made to extract the performance metric of the algorithm. A head and neck case, typical of IMRT planning, was also tested. Results: The reconstructed CT images based on this new replacement scheme show a significant improvement in image quality for patients with metallic dental objects compared to the MAR algorithms based on the interpolation scheme. For the phantom, the authors showed that the artifact reduction algorithm can efficiently recover the CT numbers in the area next to the metallic objects. Conclusions: The authors presented a new and efficient method for artifact reduction due to multiple small metallic objects. The obtained results from phantoms and clinical cases fully validate the proposed approach.« less

A longitudinal test of the demand-control model using specific job demands and specific job control.

PubMed

de Jonge, Jan; van Vegchel, Natasja; Shimazu, Akihito; Schaufeli, Wilmar; Dormann, Christian

2010-06-01

Supportive studies of the demand-control (DC) model were more likely to measure specific demands combined with a corresponding aspect of control. A longitudinal test of Karasek's (Adm Sci Q. 24:285-308, 1) job strain hypothesis including specific measures of job demands and job control, and both self-report and objectively recorded well-being. Job strain hypothesis was tested among 267 health care employees from a two-wave Dutch panel survey with a 2-year time lag. Significant demand/control interactions were found for mental and emotional demands, but not for physical demands. The association between job demands and job satisfaction was positive in case of high job control, whereas this association was negative in case of low job control. In addition, the relation between job demands and psychosomatic health symptoms/sickness absence was negative in case of high job control and positive in case of low control. Longitudinal support was found for the core assumption of the DC model with specific measures of job demands and job control as well as self-report and objectively recorded well-being.

Effort-reward imbalance and work ability: cross-sectional and longitudinal findings from the Second German Sociomedical Panel of Employees

PubMed Central

2012-01-01

Background Although data from longitudinal studies are sparse, effort-reward imbalance (ERI) seems to affect work ability. However, the potential pathway from restricted work ability to ERI must also be considered. Therefore, the aim of our study was to analyse cross-sectional and longitudinal associations between ERI and work ability and vice versa. Methods Data come from the Second German Sociomedical Panel of Employees. Logistic regression models were estimated to determine cross-sectional and longitudinal associations. The sample used to predict new cases of poor or moderate work ability was restricted to cases with good or excellent work ability at baseline. The sample used to predict new cases of ERI was restricted to persons without ERI at baseline. Results The cross-sectional analysis included 1501 full-time employed persons. The longitudinal analyses considered 600 participants with good or excellent baseline work ability and 666 participants without baseline ERI, respectively. After adjustment for socio-demographic variables, health-related behaviour and factors of the work environment, ERI was cross-sectionally associated with poor or moderate work ability (OR = 1.980; 95% CI: 1.428 to 2.747). Longitudinally, persons with ERI had 2.1 times higher odds of poor or moderate work ability after one year (OR = 2.093; 95% CI: 1.047 to 4.183). Conversely, persons with poor or moderate work ability had 2.6 times higher odds of an ERI after one year (OR = 2.573; 95% CI: 1.314 to 5.041). Conclusions Interventions that enable workers to cope with ERI or address indicators of ERI directly could promote the maintenance of work ability. Integration management programmes for persons with poor work ability should also consider their psychosocial demands. PMID:23067110

Socioeconomic Outcomes in Adults Malnourished in the First Year of Life: A 40-Year Study

PubMed Central

Bryce, Cyralene; Waber, Deborah P.; Zichlin, Miriam L.; Fitzmaurice, Garret M.; Eaglesfield, David

2012-01-01

OBJECTIVE: Lifelong functional, adaptive, and economic outcomes of moderate to severe infantile malnutrition are not well known. We assessed social status and income at midlife in a cohort of Barbadian adults, hospitalized for protein-energy malnutrition (PEM) during the first year of life, with good nutrition and health thereafter, in the context of a 40-year longitudinal case-control study. We also examined to what extent childhood IQ mediated any group differences. METHODS: Educational achievement, occupational status, and standard of living were assessed by the Hollingshead scales and a site-specific Ecology Questionnaire in Barbadian adults (aged 37–43 years) with a history of malnutrition (n = 80) and a matched healthy control group (n = 63), classmates of the index cases. Malnutrition effects, adjusted for childhood standard of living, were estimated by longitudinal multiple regression analyses, with and without childhood IQ, in the models. RESULTS: PEM predicted poorer socioeconomic outcomes with medium to large effect sizes (0.50–0.94), but childhood IQ substantially attenuated the magnitude of these effects (adjusted effect sizes: 0.17–0.34). The gap in weekly household income between the PEM and control groups increased substantially over the life span (P < .001). CONCLUSIONS: Moderate to severe PEM during the first year of life with adequate nutrition and health care thereafter is associated with significant depression of socioeconomic outcomes in adulthood, mediated in part by cognitive compromise in affected individuals. This finding underscores the potential long-term economic burden of infant malnutrition, which is of major concern given the continued high prevalence of malnutrition worldwide. PMID:22732170

The effect of state medicaid case-mix payment on nursing home resident acuity.

PubMed

Feng, Zhanlian; Grabowski, David C; Intrator, Orna; Mor, Vincent

2006-08-01

To examine the relationship between Medicaid case-mix payment and nursing home resident acuity. Longitudinal Minimum Data Set (MDS) resident assessments from 1999 to 2002 and Online Survey Certification and Reporting (OSCAR) data from 1996 to 2002, for all freestanding nursing homes in the 48 contiguous U.S. states. We used a facility fixed-effects model to examine the effect of introducing state case-mix payment on changes in nursing home case-mix acuity. Facility acuity was measured by aggregating the nursing case-mix index (NCMI) from the MDS using the Resource Utilization Group (Version III) resident classification system, separately for new admits and long-stay residents, and by an OSCAR-derived index combining a range of activity of daily living dependencies and special treatment measures. We followed facilities over the study period to create a longitudinal data file based on the MDS and OSCAR, respectively, and linked facilities with longitudinal data on state case-mix payment policies for the same period. Across three acuity measures and two data sources, we found that states shifting to case-mix payment increased nursing home acuity levels over the study period. Specifically, we observed a 2.5 percent increase in the average acuity of new admits and a 1.3 to 1.4 percent increase in the acuity of long-stay residents, following the introduction of case-mix payment. The adoption of case-mix payment increased access to care for higher acuity Medicaid residents.

Policy, Service Pathways and Mortality: A 10-Year Longitudinal Study of People with Profound Intellectual and Multiple Disabilities

ERIC Educational Resources Information Center

Hogg, James; Juhlberg, K.; Lambe, L.

2007-01-01

Background: One hundred and forty-two children and adults with profound intellectual and multiple disabilities were identified in 1993 in a single Scottish region on whom detailed information was collected via a postal questionnaire survey. Methods: They were followed up in 2003. The time spanned represented a period of significant policy change…

Multiple-Group Confirmatory Factor Analysis in R--A Tutorial in Measurement Invariance with Continuous and Ordinal Indicators

ERIC Educational Resources Information Center

Hirschfeld, Gerrit; von Brachel, Ruth

2014-01-01

Multiple-group confirmatory factor analysis (MG-CFA) is among the most productive extensions of structural equation modeling. Many researchers conducting cross-cultural or longitudinal studies are interested in testing for measurement and structural invariance. The aim of the present paper is to provide a tutorial in MG-CFA using the freely…

Corpus Callosum Function in Verbal Dichotic Listening: Inferences from a Longitudinal Follow-Up of Relapsing-Remitting Multiple Sclerosis Patients

ERIC Educational Resources Information Center

Gadea, Marien; Marti-Bonmati, Luis; Arana, Estanislao; Espert, Raul; Salvador, Alicia; Casanova, Bonaventura

2009-01-01

This study conducted a follow-up of 13 early-onset slightly disabled Relapsing-Remitting Multiple Sclerosis (RRMS) patients within an year, evaluating both CC area measurements in a midsagittal Magnetic Resonance (MR) image, and Dichotic Listening (DL) testing with stop consonant vowel (C-V) syllables. Patients showed a significant progressive…

Reforming primary healthcare: from public policy to organizational change.

PubMed

Gilbert, Frédéric; Denis, Jean-Louis; Lamothe, Lise; Beaulieu, Marie-Dominique; D'amour, Danielle; Goudreau, Johanne

2015-01-01

Governments everywhere are implementing reform to improve primary care. However, the existence of a high degree of professional autonomy makes large-scale change difficult to achieve. The purpose of this paper is to elucidate the change dynamics and the involvement of professionals in a primary healthcare reform initiative carried out in the Canadian province of Quebec. An empirical approach was used to investigate change processes from the inception of a public policy to the execution of changes in professional practices. The data were analysed from a multi-level, combined contextualist-processual perspective. Results are based on a longitudinal multiple-case study of five family medicine groups, which was informed by over 100 interviews, questionnaires, and documentary analysis. The results illustrate the multiple processes observed with the introduction of planned large-scale change in primary care services. The analysis of change content revealed that similar post-change states concealed variations between groups in the scale of their respective changes. The analysis also demonstrated more precisely how change evolved through the introduction of "intermediate change" and how cycles of prescribed and emergent mechanisms distinctively drove change process and change content, from the emergence of the public policy to the change in primary care service delivery. This research was conducted among a limited number of early policy adopters. However, given the international interest in turning to the medical profession to improve primary care, the results offer avenues for both policy development and implementation. The findings offer practical insights for those studying and managing large-scale transformations. They provide a better understanding of how deliberate reforms coexist with professional autonomy through an intertwining of change content and processes. This research is one of few studies to examine a primary care reform from emergence to implementation using a longitudinal multi-level design.

Examining the Interplay of Processes Across Multiple Time-Scales: Illustration With the Intraindividual Study of Affect, Health, and Interpersonal Behavior (iSAHIB).

PubMed

Ram, Nilam; Conroy, David E; Pincus, Aaron L; Lorek, Amy; Rebar, Amanda; Roche, Michael J; Coccia, Michael; Morack, Jennifer; Feldman, Josh; Gerstorf, Denis

Human development is characterized by the complex interplay of processes that manifest at multiple levels of analysis and time-scales. We introduce the Intraindividual Study of Affect, Health and Interpersonal Behavior (iSAHIB) as a model for how multiple time-scale study designs facilitate more precise articulation of developmental theory. Combining age heterogeneity, longitudinal panel, daily diary, and experience sampling protocols, the study made use of smartphone and web-based technologies to obtain intensive longitudinal data from 150 persons age 18-89 years as they completed three 21-day measurement bursts ( t = 426 bursts, t = 8,557 days) wherein they provided reports on their social interactions ( t = 64,112) as they went about their daily lives. We illustrate how multiple time-scales of data can be used to articulate bioecological models of development and the interplay among more 'distal' processes that manifest at 'slower' time-scales (e.g., age-related differences and burst-to-burst changes in mental health) and more 'proximal' processes that manifest at 'faster' time-scales (e.g., changes in context that progress in accordance with the weekly calendar and family influence processes).

Temporal association of cannabis use with symptoms in individuals at clinical high risk for psychosis.

PubMed

Corcoran, Cheryl M; Kimhy, David; Stanford, Arielle; Khan, Shamir; Walsh, Julie; Thompson, Judy; Schobel, Scott; Harkavy-Friedman, Jill; Goetz, Ray; Colibazzi, Tiziano; Cressman, Victoria; Malaspina, Dolores

2008-12-01

Cannabis use is reported to increase the risk for psychosis, but no prospective study has longitudinally examined drug use and symptoms concurrently in clinical high risk cases. We prospectively followed for up to 2 years 32 cases who met research criteria for prodromal psychosis to examine the relationship between substance use and clinical measures. Cases with a baseline history of cannabis use (41%) were older, but did not differ in clinical measures. Longitudinal assessments showed these cases had significantly more perceptual disturbances and worse functioning during epochs of increased cannabis use that were unexplained by concurrent use of other drugs or medications. These data demonstrate that cannabis use may be a risk factor for the exacerbation of subthreshold psychotic symptoms, specifically perceptual disturbances, in high risk cases.

Sex Stratification, Technology and Organizational Change: A Longitudinal Case Study of AT&T.

ERIC Educational Resources Information Center

Hacker, Sally L.

1979-01-01

Recent technological displacement in AT&T affected workers differentially by sex. This longitudinal analysis of changes in AT&T's organizational structure addresses the tendency of organizational research to ignore the variable of sex in the study of change. (Author/RLV)

Investigation of 2‐stage meta‐analysis methods for joint longitudinal and time‐to‐event data through simulation and real data application

PubMed Central

Tudur Smith, Catrin; Gueyffier, François; Kolamunnage‐Dona, Ruwanthi

2017-01-01

Background Joint modelling of longitudinal and time‐to‐event data is often preferred over separate longitudinal or time‐to‐event analyses as it can account for study dropout, error in longitudinally measured covariates, and correlation between longitudinal and time‐to‐event outcomes. The joint modelling literature focuses mainly on the analysis of single studies with no methods currently available for the meta‐analysis of joint model estimates from multiple studies. Methods We propose a 2‐stage method for meta‐analysis of joint model estimates. These methods are applied to the INDANA dataset to combine joint model estimates of systolic blood pressure with time to death, time to myocardial infarction, and time to stroke. Results are compared to meta‐analyses of separate longitudinal or time‐to‐event models. A simulation study is conducted to contrast separate versus joint analyses over a range of scenarios. Results Using the real dataset, similar results were obtained by using the separate and joint analyses. However, the simulation study indicated a benefit of use of joint rather than separate methods in a meta‐analytic setting where association exists between the longitudinal and time‐to‐event outcomes. Conclusions Where evidence of association between longitudinal and time‐to‐event outcomes exists, results from joint models over standalone analyses should be pooled in 2‐stage meta‐analyses. PMID:29250814

Longitudinal plasma metanephrines preceding pheochromocytoma diagnosis: a retrospective case-control serum repository study.

PubMed

Olson, S W; Yoon, S; Baker, T; Prince, L K; Oliver, D; Abbott, K C

2016-03-01

Plasma metanephrines (PMN) are highly sensitive for diagnosis of pheochromocytoma, but the natural history of PMN before pheochromocytoma diagnosis has not been previously described. The aim of the study was to compare the progression of PMN before pheochromocytoma diagnosis to matched healthy and essential hypertension disease controls. A retrospective case-control Department of Defense Serum Repository (DoDSR) study. We performed a DoDSR study that compared three longitudinal pre-diagnostic PMN for 30 biopsy-proven pheochromocytoma cases to three longitudinal PMN for age, sex, race, and age of serum sample matched healthy and essential hypertension disease controls. Predominant metanephrine (MN) or normetanephrine (NMN) production was identified for each case and converted to a percentage of the upper limit of normal to allow analysis of all cases together. PMN were measured by Quest Diagnostics. The predominant plasma metanephrine (PPM) was >100 and 300% of the upper limit of normal a median of 6.6 and 4.1 years before diagnosis respectively. A greater percentage of pheochromocytoma patients had a PPM >100 and >300% of the upper limit of normal compared with combined healthy and essential hypertension disease controls <2, 2-8, and >8 years prior to diagnosis. For patients with a baseline PPM 90-300% of the upper limit of normal, a 25% rate of rise per year was 100% specific for pheochromocytoma. PPMs elevate years before diagnosis which suggests that delayed diagnoses are common. For mild PMN elevations, follow-up longitudinal PMN trends may provide a highly specific and economical diagnostic tool. © 2016 European Society of Endocrinology.

Mixed-effects location and scale Tobit joint models for heterogeneous longitudinal data with skewness, detection limits, and measurement errors.

PubMed

Lu, Tao

2017-01-01

The joint modeling of mean and variance for longitudinal data is an active research area. This type of model has the advantage of accounting for heteroscedasticity commonly observed in between and within subject variations. Most of researches focus on improving the estimating efficiency but ignore many data features frequently encountered in practice. In this article, we develop a mixed-effects location scale joint model that concurrently accounts for longitudinal data with multiple features. Specifically, our joint model handles heterogeneity, skewness, limit of detection, measurement errors in covariates which are typically observed in the collection of longitudinal data from many studies. We employ a Bayesian approach for making inference on the joint model. The proposed model and method are applied to an AIDS study. Simulation studies are performed to assess the performance of the proposed method. Alternative models under different conditions are compared.

Political violence and child adjustment: longitudinal tests of sectarian antisocial behavior, family conflict, and insecurity as explanatory pathways.

PubMed

Cummings, Edward M; Merrilees, Christine E; Schermerhorn, Alice C; Goeke-Morey, Marcie C; Shirlow, Peter; Cairns, Ed

2012-01-01

Understanding the impact of political violence on child maladjustment is a matter of international concern. Recent research has advanced a social ecological explanation for relations between political violence and child adjustment. However, conclusions are qualified by the lack of longitudinal tests. Toward examining pathways longitudinally, mothers and their adolescents (M = 12.33, SD = 1.78, at Time 1) from 2-parent families in Catholic and Protestant working class neighborhoods in Belfast, Northern Ireland, completed measures assessing multiple levels of a social ecological model. Utilizing autoregressive controls, a 3-wave longitudinal model test (T1, n = 299; T2, n = 248; T3, n = 197) supported a specific pathway linking sectarian community violence, family conflict, children's insecurity about family relationships, and adjustment problems. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc.

Lung function in type 2 diabetes: the Normative Aging Study.

PubMed

Litonjua, Augusto A; Lazarus, Ross; Sparrow, David; Demolles, Debbie; Weiss, Scott T

2005-12-01

Cross-sectional studies have noted that subjects with diabetes have lower lung function than non-diabetic subjects. We conducted this analysis to determine whether diabetic subjects have different rates of lung function change compared with non-diabetic subjects. We conducted a nested case-control analysis in 352 men who developed diabetes and 352 non-diabetic subjects in a longitudinal observational study of aging in men. We assessed lung function among cases and controls at three time points: Time0, prior to meeting the definition of diabetes; Time1, the point when the definition of diabetes was met; and Time2, the most recent follow-up exam. Cases had lower forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) at all time points, even with adjustment for age, height, weight, and smoking. In multiple linear regression models adjusting for relevant covariates, there were no differences in rates of FEV1 or FVC change over time between cases and controls. Men who are predisposed to develop diabetes have decreased lung function many years prior to the diagnosis, compared with men who do not develop diabetes. This decrement in lung function remains after the development of diabetes. We postulate that mechanisms involved in the insulin resistant state contribute to the diminished lung function observed in our subjects.

Composite marginal quantile regression analysis for longitudinal adolescent body mass index data.

PubMed

Yang, Chi-Chuan; Chen, Yi-Hau; Chang, Hsing-Yi

2017-09-20

Childhood and adolescenthood overweight or obesity, which may be quantified through the body mass index (BMI), is strongly associated with adult obesity and other health problems. Motivated by the child and adolescent behaviors in long-term evolution (CABLE) study, we are interested in individual, family, and school factors associated with marginal quantiles of longitudinal adolescent BMI values. We propose a new method for composite marginal quantile regression analysis for longitudinal outcome data, which performs marginal quantile regressions at multiple quantile levels simultaneously. The proposed method extends the quantile regression coefficient modeling method introduced by Frumento and Bottai (Biometrics 2016; 72:74-84) to longitudinal data accounting suitably for the correlation structure in longitudinal observations. A goodness-of-fit test for the proposed modeling is also developed. Simulation results show that the proposed method can be much more efficient than the analysis without taking correlation into account and the analysis performing separate quantile regressions at different quantile levels. The application to the longitudinal adolescent BMI data from the CABLE study demonstrates the practical utility of our proposal. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

A longitudinal multilevel CFA-MTMM model for interchangeable and structurally different methods

PubMed Central

Koch, Tobias; Schultze, Martin; Eid, Michael; Geiser, Christian

2014-01-01

One of the key interests in the social sciences is the investigation of change and stability of a given attribute. Although numerous models have been proposed in the past for analyzing longitudinal data including multilevel and/or latent variable modeling approaches, only few modeling approaches have been developed for studying the construct validity in longitudinal multitrait-multimethod (MTMM) measurement designs. The aim of the present study was to extend the spectrum of current longitudinal modeling approaches for MTMM analysis. Specifically, a new longitudinal multilevel CFA-MTMM model for measurement designs with structurally different and interchangeable methods (called Latent-State-Combination-Of-Methods model, LS-COM) is presented. Interchangeable methods are methods that are randomly sampled from a set of equivalent methods (e.g., multiple student ratings for teaching quality), whereas structurally different methods are methods that cannot be easily replaced by one another (e.g., teacher, self-ratings, principle ratings). Results of a simulation study indicate that the parameters and standard errors in the LS-COM model are well recovered even in conditions with only five observations per estimated model parameter. The advantages and limitations of the LS-COM model relative to other longitudinal MTMM modeling approaches are discussed. PMID:24860515

The case for causal influences of action videogame play upon vision and attention.

PubMed

Kristjánsson, Árni

2013-05-01

Over the past decade, exciting findings have surfaced suggesting that routine action videogame play improves attentional and perceptual skills. Apparently, performance during multiple-object tracking, useful-field-of-view tests, and task switching improves, contrast sensitivity and spatial-resolution thresholds decrease, and the attentional blink and backward masking are lessened by short-term training on action videogames. These are remarkable findings showing promise for the training of attention and the treatment of disorders of attentional function. While the findings are interesting, evidence of causal influences of videogame play is not as strong as is often claimed. In many studies, observers with game play experience and those without are tested. Such studies do not address causality, since preexisting differences are not controlled for. Other studies investigate the training of videogame play, with some evidence of training benefits. Methodological shortcomings and potential confounds limit their impact, however, and they have not always been replicated. No longitudinal studies on videogame training exist, but these may be required to provide conclusive answers about any benefits of videogame training and any interaction with preexisting differences. Suggestions for methodological improvement are made here, including recommendations for longitudinal studies. Such studies may become crucial for the field of attentional training to reach its full potential.

A longitudinal analysis of nursing home outcomes.

PubMed Central

Porell, F; Caro, F G; Silva, A; Monane, M

1998-01-01

OBJECTIVE: To investigate resident and facility attributes associated with long-term care health outcomes in nursing homes. DATA SOURCES: Quarterly Management Minutes Questionnaire (MMQ) survey data for Medicaid case-mix reimbursement of nursing homes in Massachusetts from 1991 to 1994, for specification of outcomes and resident attributes. Facility attributes are specified from cost report data. STUDY DESIGN: Multivariate logistic and "state-dependence" regression models are estimated for survival, ADL functional status, incontinence status, and mental status outcomes from longitudinal residence histories of Medicaid residents spanning 3 to 36 months in length. Outcomes are specified to be a function of resident demographic and diagnostic attributes and facility-level operating and nurse staffing attributes. PRINCIPAL FINDINGS: The estimated parameters for resident demographic and diagnostic attributes showed a great deal of construct validity with respect to clinical expectations regarding risk factors for adverse outcomes. Few facility attributes were associated with outcomes generally, and none was significantly associated with all four outcomes. CONCLUSIONS: The absence of uniform associations between facility attributes and the various long-term care health outcomes studied suggests that strong facility performance on one health outcome may coexist with much weaker performance on other outcomes. This has implications for the aggregation of individual facility performance measures on multiple outcomes and the development of overall outcome performance measures. PMID:9776939

Longitudinal patterns and predictors of multiple health risk behaviors among adolescents: The TRAILS study.

PubMed

de Winter, Andrea F; Visser, Leenke; Verhulst, Frank C; Vollebergh, Wilma A M; Reijneveld, Sijmen A

2016-03-01

Most studies on multiple health risk behaviors among adolescents have cross-sectionally studied a limited number of health behaviors or determinants. To examine the prevalence, longitudinal patterns and predictors of individual and multiple health risk behaviors among adolescents. Eight health risk behaviors (no regular consumption of fruit, vegetables or breakfast, overweight or obesity, physical inactivity, smoking, alcohol use and cannabis use) were assessed in a prospective population study (second and third wave). Participants were assessed in three waves between ages 10 and 17 (2001-2008; n=2230). Multiple linear regression was used to assess the influence of gender, self-control, parental health risk behaviors, parental monitoring and socioeconomic factors on the number of health risk behaviors adjusted for preceding multiple health risk behaviors (analysis: 2013-2014). Rates of >5 health risk behaviors were high: 3.6% at age 13.5 and 10.2% at age 16. Smoking at age 13.5 was frequently associated with health risk behaviors at age 16. No regular consumption of fruit, vegetables and breakfast, overweight or obesity, physical inactivity and smoking predicted the co-occurrence of health risk behaviors at follow-up. Significant predictors of the development of multiple health risk behaviors were adolescents' levels of self-control, socioeconomic status and maternal smoking. Multiple health risk behaviors are common among adolescents. Individual and social factors predict changes in multiple health risk behaviors, showing that prevention targeting multiple risk behaviors is needed. Special attention should be paid to adolescents with low self-control and families with low socioeconomic status or a mother who smokes. Copyright © 2015 Elsevier Inc. All rights reserved.

The Three-Year Course of Multiple Substance Use Disorders in the United States: A National Longitudinal Study

PubMed Central

McCabe, Sean Esteban; West, Brady T.

2016-01-01

Objectives This study examined the three-year course of multiple co-occurring substance use disorders (SUDs) based on longitudinal survey data from a large, nationally representative sample. Methods National estimates of the prevalence of DSM-IV SUDs were derived by analyzing data from structured, face-to-face diagnostic interviews as part of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), which collected data from a large nationally representative sample of non-institutionalized U.S. adults at two waves (2001–2002 and 2004–2005; n = 34,653). Results U.S. adults with multiple past-year SUDs at Wave 1 were more likely than those with an individual past-year SUD at Wave 1 to report at least one past-year SUD at Wave 2. There were several sociodemographic characteristics and psychiatric disorders (i.e., male, younger age, never married, sexual minority identity, nicotine dependence, and anxiety, mood and personality disorders) associated with increased odds of developing multiple SUDs and having three-year persistence of multiple SUDs. The majority of adults with multiple past-year SUDs had a lifetime personality disorder and did not utilize substance abuse treatment or other help-seeking. Conclusions Multiple SUDs are associated with a more persistent three-year course of disease over time relative to individual-SUDs. Despite a more severe three-year course and higher rates of comorbidity with other psychiatric disorders, the majority of U.S. adults with multiple SUDs do not utilize substance abuse treatment or other help-seeking. Clinical assessments and the substance abuse literature tend to focus on drug-specific individual SUDs rather than considering multiple SUDs, which are more complex in nature. PMID:28406266

TRAJECTORIES OF ACCULTURATION AND ENCULTURATION IN RELATION TO HEAVY EPISODIC DRINKING AND MARIJUANA USE IN A SAMPLE OF MEXICAN AMERICAN SERIOUS JUVENILE OFFENDERS

PubMed Central

Losoya, Sandra H.; Knight, George P.; Chassin, Laurie; Little, Michelle; Vargas-Chanes, Delfino; Mauricio, Anne; Piquero, Alex

2009-01-01

This study examines the longitudinal relations of multiple dimensions of acculturation and enculturation to heavy episodic drinking and marijuana use in a sample of 300 male, Mexican-American, serious juvenile offenders. We track trajectories between ages 15 and 20 and also consider the effects of participants’ time spent residing in supervised settings during these years. Results showed some (although not entirely consistent) support for the hypothesis that bicultural adaptation is most functional in terms of lowered substance use involvement. The current findings demonstrate the importance of examining these relations longitudinally and among multiple dimensions of acculturation and enculturation, and they call into question simple models that suggest that greater acculturation is associated with greater substance use among Mexican-American adolescents. PMID:20198119

Analyzing change in short-term longitudinal research using cohort-sequential designs.

PubMed

Anderson, E R

1993-12-01

This article illustrates a method for approximating longitudinal data analysis by combining information from different overlapping age groups to form a single developmental growth curve. Using this method, hypotheses about the form of growth, the extent of individual differences in growth, and factors that affect the rate and pattern of growth are investigated. The example used to illustrate this method examines the growth of externalizing behavior and of negativity in parent-child relationships during early adolescence using assessments from multiple methods and multiple informants. These 3 dimensions changed significantly during this period, with parental negativity increasing more rapidly after age 12. However, there were substantial individual differences in the pattern of change in these dimensions. Gender of child and type of family situation (nondivorced, divorced, and remarried) were investigated as possible factors affecting change.

In vivo longitudinal MRI and behavioral studies in experimental spinal cord injury.

PubMed

Sundberg, Laura M; Herrera, Juan J; Narayana, Ponnada A

2010-10-01

Comprehensive in vivo longitudinal studies that include multi-modal magnetic resonance imaging (MRI) and a battery of behavioral assays to assess functional outcome were performed at multiple time points up to 56 days post-traumatic spinal cord injury (SCI) in rodents. The MRI studies included high-resolution structural imaging for lesion volumetry, and diffusion tensor imaging (DTI) for probing the white matter integrity. The behavioral assays included open-field locomotion, grid walking, inclined plane, computerized activity box performance, and von Frey filament tests. Additionally, end-point histology was assessed for correlation with both the MRI and behavioral data. The temporal patterns of the lesions were documented on structural MRI. DTI studies showed significant changes in white matter that is proximal to the injury epicenter and persisted to day 56. White matter in regions up to 1 cm away from the injury epicenter that appeared normal on conventional MRI also exhibited changes that were indicative of tissue damage, suggesting that DTI is a more sensitive measure of the evolving injury. Correlations between DTI and histology after SCI could not be firmly established, suggesting that injury causes complex pathological changes in multiple tissue components that affect the DTI measures. Histological evidence confirmed a significant decrease in myelin and oligodendrocyte presence 56 days post-SCI. Multiple assays to evaluate aspects of functional recovery correlated with histology and DTI measures, suggesting that damage to specific white matter tracts can be assessed and tracked longitudinally after SCI.

Transfer of the second to the first metatarsal ray in a case of lawn mower injury: a case report.

PubMed

Sassu, Paolo; Tsai, Tsu Min

2009-01-01

The medial longitudinal arch of the foot plays a major role for a physiologic transfer of the load from the heel to the forefoot during walking and running. Traumatic amputation that involve either the great toe or the whole first metatarsal bone can lead to collapse of the medial longitudinal arch, overload of the metatarsal heads, and painful callus formation. If replant of the amputated part is not possible or has failed, it is advisable to reconstruct the medial longitudinal arch in order to re-establish a functional transfer of the load in the foot. We present a case of a young lady who suffered from traumatic amputation at the distal third of the first metatarsal. Replantation failed due to the severity of the initial injury. Despite a good coverage of the defect with a lateral arm flap, the patient developed a painful plantar callus underneath the amputated stump. The adjacent second metatarsal ray was then raised as a pedicled flap including bone and soft tissues and transferred to the first ray in order to reconstruct a physiologic medial longitudinal arch. The patient had excellent functional results with no recurrence of the callus. (c) 2008 Wiley-Liss, Inc.

Longitudinal association of hemostatic factors with risk for cancers of the breast, colorectum, and lung among postmenopausal women.

PubMed

Kabat, Geoffrey C; Salazar, Christian R; Zaslavsky, Oleg; Lane, Dorothy S; Rohan, Thomas E

2016-09-01

The aim of this study was to examine whether hemostatic factors associated with coagulation and inflammation pathways are associated with cancer risk in postmenopausal women. We used data from the Women's Health Initiative study to examine the association of plasma fibrinogen levels, factor VII antigen activity, and factor VII concentration measured at baseline and during follow-up with the risk for cancers of the breast, colorectum, and lung. Among 5287 women who were followed up for a median of 11.4 years, 275 cases of breast cancer, 102 cases of colorectal cancer, and 90 cases of lung cancer were identified. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for the association of hemostatic factors with each cancer. Hemostatic factors were not associated with breast cancer in either baseline or longitudinal analyses. Baseline hemostatic factors showed weak associations with colorectal cancer; however, no association was seen in longitudinal analyses. Fibrinogen was positively associated with lung cancer in both baseline and longitudinal analyses; the association was seen only in never and former smokers, not in current smokers. We found no evidence of an association between hemostatic factors and breast or colorectal cancer in postmenopausal women. The positive association of fibrinogen levels with lung cancer requires confirmation in larger studies.

Life Outcomes and Higher Education: The Need for Longitudinal Research Using a Broad Range of Quality of Life Indicators.

PubMed

Sheppard-Jones, Kathleen; Kleinert, Harold; Butler, Laura; Whaley, Barry

2018-02-01

Higher education is increasingly becoming an option for young adults with intellectual disability (ID). Although initial evaluations of postsecondary education for this population have been promising, a broader "quality of life" framework needs to be adopted in order to truly understand the impact of these programs. Moreover, researchers and program evaluators must collect longitudinal data that follows former students for multiple years and uses multiple measures. We conducted a pilot evaluation of the life outcomes of students who had attended at least two semesters in Kentucky's supported higher education program for students with ID, collecting data on life status and experiences using measures from the National Core Indicators-Adult Consumer Survey. The findings from this pilot study show better outcomes for young adults who participated in a postsecondary education program compared to young adults who did not, but these findings need to be considered in light of several limitations. In many respects, our data provided more new questions than answers. Recommendations for collecting and evaluating broad-based, longitudinal data to gain insight into the potential benefits of postsecondary education for people with intellectual disability are discussed.

Role of multiple cusps in tooth fracture.

PubMed

Barani, Amir; Bush, Mark B; Lawn, Brian R

2014-07-01

The role of multiple cusps in the biomechanics of human molar tooth fracture is analysed. A model with four cusps at the bite surface replaces the single dome structure used in previous simulations. Extended finite element modelling, with provision to embed longitudinal cracks into the enamel walls, enables full analysis of crack propagation from initial extension to final failure. The cracks propagate longitudinally around the enamel side walls from starter cracks placed either at the top surface (radial cracks) or from the tooth base (margin cracks). A feature of the crack evolution is its stability, meaning that extension occurs steadily with increasing applied force. Predictions from the model are validated by comparison with experimental data from earlier publications, in which crack development was followed in situ during occlusal loading of extracted human molars. The results show substantial increase in critical forces to produce longitudinal fractures with number of cuspal contacts, indicating a capacity for an individual tooth to spread the load during mastication. It is argued that explicit critical force equations derived in previous studies remain valid, at the least as a means for comparing the capacity for teeth of different dimensions to sustain high bite forces. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physical Aggression and Language Ability from 17 to 72 Months: Cross-Lagged Effects in a Population Sample

PubMed Central

Girard, Lisa-Christine; Pingault, Jean-Baptiste; Falissard, Bruno; Boivin, Michel; Dionne, Ginette; Tremblay, Richard E.

2014-01-01

Background Does poor language ability in early childhood increase the likelihood of physical aggression or is language ability delayed by frequent physical aggression? This study examined the longitudinal associations between physical aggression and language ability from toddlerhood to early childhood in a population sample while controlling for parenting behaviours, non-verbal intellectual functioning, and children’s sex. Methods Children enrolled in the Quebec Longitudinal Study of Child Development (QLSCD) (N = 2, 057) were assessed longitudinally from 17 to 72 months via parent reports and standardized assessments. Results The cross-lagged models revealed modest reciprocal associations between physical aggression and language performance from 17 to 41 months but not thereafter. Conclusions Significant associations between physical aggression and poor language ability are minimal and limited to the period when physical aggression and language performance are both substantially increasing. During that period parenting behaviours may play an important role in supporting language ability while reducing the frequency of physical aggression. Further studies are needed that utilize multiple assessments of physical aggression, assess multiple domains of language abilities, and that examine the potential mediating role of parenting behaviours between 12 and 48 months. PMID:25375971

A 20-Year multi-followup longitudinal study assessing whether antipsychotic medications contribute to work functioning in schizophrenia.

PubMed

Harrow, Martin; Jobe, Thomas H; Faull, Robert N; Yang, Jie

2017-10-01

To assess the long-term effectiveness of antipsychotic medications in facilitating work functioning in patients with schizophrenia we conducted longitudinal multifollowup research on 139 initially psychotic patients. The 70 patients with schizophrenia and 69 initially psychotic mood disordered control patients were followed up 6 times over 20 years. We compared the influence on work functioning of patients with schizophrenia continuously prescribed antipsychotics with patients with schizophrenia not prescribed antipsychotics, using statistical controls for inter-subject differences. While antipsychotics reduce or eliminate flagrant psychosis for most patients with schizophrenia at acute hospitalizations, four years later and continually until the 20 year followups, patients with schizophrenia not prescribed antipsychotics had significantly better work functioning. The work performance of the patients who were continuously prescribed antipsychotics was at a low rate and did not improve over time. Multiple other factors also interfere with work functioning. The data suggest that some patients with schizophrenia not prescribed antipsychotics for prolonged periods can function relatively well. Multiple other factors are associated with poor post-hospital work performance. The longitudinal data raise questions about prolonged treatment of schizophrenia with antipsychotic medications. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimation of the longitudinal and lateral-directional aerodynamic parameters from flight data for the NASA F/A-18 HARV

NASA Technical Reports Server (NTRS)

Napolitano, Marcello R.

1996-01-01

This progress report presents the results of an investigation focused on parameter identification for the NASA F/A-18 HARV. This aircraft was used in the high alpha research program at the NASA Dryden Flight Research Center. In this study the longitudinal and lateral-directional stability derivatives are estimated from flight data using the Maximum Likelihood method coupled with a Newton-Raphson minimization technique. The objective is to estimate an aerodynamic model describing the aircraft dynamics over a range of angle of attack from 5 deg to 60 deg. The mathematical model is built using the traditional static and dynamic derivative buildup. Flight data used in this analysis were from a variety of maneuvers. The longitudinal maneuvers included large amplitude multiple doublets, optimal inputs, frequency sweeps, and pilot pitch stick inputs. The lateral-directional maneuvers consisted of large amplitude multiple doublets, optimal inputs and pilot stick and rudder inputs. The parameter estimation code pEst, developed at NASA Dryden, was used in this investigation. Results of the estimation process from alpha = 5 deg to alpha = 60 deg are presented and discussed.

Optimization of Sample Preparation and Instrumental Parameters for the Rapid Analysis of Drugs of Abuse in Hair samples by MALDI-MS/MS Imaging

NASA Astrophysics Data System (ADS)

Flinders, Bryn; Beasley, Emma; Verlaan, Ricky M.; Cuypers, Eva; Francese, Simona; Bassindale, Tom; Clench, Malcolm R.; Heeren, Ron M. A.

2017-08-01

Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) has been employed to rapidly screen longitudinally sectioned drug user hair samples for cocaine and its metabolites using continuous raster imaging. Optimization of the spatial resolution and raster speed were performed on intact cocaine contaminated hair samples. The optimized settings (100 × 150 μm at 0.24 mm/s) were subsequently used to examine longitudinally sectioned drug user hair samples. The MALDI-MS/MS images showed the distribution of the most abundant cocaine product ion at m/z 182. Using the optimized settings, multiple hair samples obtained from two users were analyzed in approximately 3 h: six times faster than the standard spot-to-spot acquisition method. Quantitation was achieved using longitudinally sectioned control hair samples sprayed with a cocaine dilution series. A multiple reaction monitoring (MRM) experiment was also performed using the `dynamic pixel' imaging method to screen for cocaine and a range of its metabolites, in order to differentiate between contaminated hairs and drug users. Cocaine, benzoylecgonine, and cocaethylene were detectable, in agreement with analyses carried out using the standard LC-MS/MS method. [Figure not available: see fulltext.

Closing the gap: Longitudinal changes in employment for Australians with multiple sclerosis.

PubMed

Van Dijk, Pieter A; Kirk-Brown, Andrea K; Taylor, Bruce; van der Mei, Ingrid

2017-09-01

Previous studies have documented far lower employment participation rates for people with multiple sclerosis (PwMS) compared to the general population. In a large national sample of PwMS, we examined employment status, longitudinal changes in employment and the provision of modifications to work role/environment from 2010 to 2013. Employment data were collected through the Australian MS Longitudinal Study from 2010 to 2013, with 1260 people responding to all four surveys. Employment rates were compared with the Australian general population. The survey included questions on the provision of modifications to employees' work role and work environment. Employment (full- and part-time) increased from 48.8% in 2010 to 57.8% in 2013, mainly due to increases in male full-time employment. The employment gap between PwMS and the general population fell from 14.3% in 2010 to 3.5% in 2013. Male employment rates, however, remain significantly lower than the general population. The majority of PwMS who required adjustments to either their work role or environment received them. The gap in employment between PwMS and the general population has substantially reduced from 2010 to 2013, with organisations responding positively to requests for work role/environment adjustments.

The influence of interferon β-1b on gut microbiota composition in patients with multiple sclerosis.

PubMed

Castillo-Álvarez, F; Pérez-Matute, P; Oteo, J A; Marzo-Sola, M E

2018-06-09

The association between gut microbiota and animal models of multiple sclerosis has been well established; however, studies in humans are scarce. We performed a descriptive, cross-sectional study comparing the relative composition of gut microbiota in 30 patients with multiple sclerosis (15 treated with interferon β-1b, 15 not receiving this treatment) and 14 healthy controls using next generation sequencing. Patients with multiple sclerosis and controls showed differences in the proportion of Euryarchaeota, Firmicutes, Proteobacteria, Actinobacteria, and Lentisphaerae phyla and in 17 bacterial species. More specifically, we found significant differences in the proportion of Firmicutes, Actinobacteria, and Lentisphaerae and 6 bacteria species between controls and untreated patients; however, these differences disappeared when compared with treated patients. Untreated patients showed a significant reduction in the proportion of Prevotella copri compared to controls, while the bacteria was significantly more abundant in patients treated with interferon β-1b than in untreated patients, with levels resembling those observed in the healthy control group. We observed differences in gut microbiota composition between patients with multiple sclerosis and controls, and between patients treated and not treated with interferon β-1b. In most cases, no differences were observed between treated patients and healthy controls, particularly for P. copri levels. This suggests that the clinical improvements observed in patients with multiple sclerosis receiving interferon β-1b may result from the effect of the drug on gut microbiota. Longitudinal and functional studies are necessary to establish a causal relationship. Copyright © 2018 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Reliability of Classifying Multiple Sclerosis Disease Activity Using Magnetic Resonance Imaging in a Multiple Sclerosis Clinic

PubMed Central

Altay, Ebru Erbayat; Fisher, Elizabeth; Jones, Stephen E.; Hara-Cleaver, Claire; Lee, Jar-Chi; Rudick, Richard A.

2013-01-01

Objective To assess the reliability of new magnetic resonance imaging (MRI) lesion counts by clinicians in a multiple sclerosis specialty clinic. Design An observational study. Setting A multiple sclerosis specialty clinic. Patients Eighty-five patients with multiple sclerosis participating in a National Institutes of Health–supported longitudinal study were included. Intervention Each patient had a brain MRI scan at entry and 6 months later using a standardized protocol. Main Outcome Measures The number of new T2 lesions, newly enlarging T2 lesions, and gadolinium-enhancing lesions were measured on the 6-month MRI using a computer-based image analysis program for the original study. For this study, images were reanalyzed by an expert neuroradiologist and 3 clinician raters. The neuroradiologist evaluated the original image pairs; the clinicians evaluated image pairs that were modified to simulate clinical practice. New lesion counts were compared across raters, as was classification of patients as MRI active or inactive. Results Agreement on lesion counts was highest for gadolinium-enhancing lesions, intermediate for new T2 lesions, and poor for enlarging T2 lesions. In 18% to 25% of the cases, MRI activity was classified differently by the clinician raters compared with the neuroradiologist or computer program. Variability among the clinical raters for estimates of new T2 lesions was affected most strongly by the image modifications that simulated low image quality and different head position. Conclusions Between-rater variability in new T2 lesion counts may be reduced by improved standardization of image acquisitions, but this approach may not be practical in most clinical environments. Ultimately, more reliable, robust, and accessible image analysis methods are needed for accurate multiple sclerosis disease-modifying drug monitoring and decision making in the routine clinic setting. PMID:23599930

Prediction of Autism at 3 Years from Behavioural and Developmental Measures in High-Risk Infants: A Longitudinal Cross-Domain Classifier Analysis

ERIC Educational Resources Information Center

Bussu, G.; Jones, E. J. H.; Charman, T.; Johnson, M. H.; Buitelaar, J. K.; Baron-Cohen, S.; Bedford, R.; Bolton, P.; Blasi, A.; Chandler, S.; Cheung, C.; Davies, K.; Elsabbagh, M.; Fernandes, J.; Gammer, I.; Garwood, H.; Gliga, T.; Guiraud, J.; Hudry, K.; Liew, M.; Lloyd-Fox, S.; Maris, H.; O'Hara, L.; Pasco, G.; Pickles, A.; Ribeiro, H.; Salomone, E.; Tucker, L.; Volein, A.

2018-01-01

We integrated multiple behavioural and developmental measures from multiple time-points using machine learning to improve early prediction of individual Autism Spectrum Disorder (ASD) outcome. We examined Mullen Scales of Early Learning, Vineland Adaptive Behavior Scales, and early ASD symptoms between 8 and 36 months in high-risk siblings (HR; n…

Component mode synthesis and large deflection vibration of complex structures. Volume 3: Multiple-mode nonlinear free and forced vibrations of beams using finite element method

NASA Technical Reports Server (NTRS)

Mei, Chuh; Shen, Mo-How

1987-01-01

Multiple-mode nonlinear forced vibration of a beam was analyzed by the finite element method. Inplane (longitudinal) displacement and inertia (IDI) are considered in the formulation. By combining the finite element method and nonlinear theory, more realistic models of structural response are obtained more easily and faster.

High-frequency ultrasonic wire bonding systems

PubMed

Tsujino; Yoshihara; Sano; Ihara

2000-03-01

The vibration characteristics of longitudinal-complex transverse vibration systems with multiple resonance frequencies of 350-980 kHz for ultrasonic wire bonding of IC, LSI or electronic devices were studied. The complex vibration systems can be applied for direct welding of semiconductor tips (face-down bonding, flip-chip bonding) and packaging of electronic devices. A longitudinal-complex transverse vibration bonding system consists of a complex transverse vibration rod, two driving longitudinal transducers 7.0 mm in diameter and a transverse vibration welding tip. The vibration distributions along ceramic and stainless-steel welding tips were measured at up to 980 kHz. A high-frequency vibration system with a height of 20.7 mm and a weight of less than 15 g was obtained.

Use of administrative records to describe longitudinal patterns of health services use among veterans.

PubMed Central

Williams, B C; Mehr, D R; Fries, B E

1994-01-01

Administrative records of the Department of Veterans Affairs (DVA) and the National Death Index were linked to create a four-year longitudinal database that describes the clinical status, hospital and nursing home use, and mortality for a nationwide cohort of persons admitted to DVA nursing homes (n = 23,039). Using Social Security Numbers as identifiers, the records of only 6% of these persons had logically inconsistent or implausible patterns. Nineteen percent of the remaining records had correctable logical errors. Information on the creation, consistency, and potential uses of this database may prove useful to health services researchers interested in describing longitudinal patterns of health care use across multiple settings within and outside the DVA. PMID:7719818

Case Study: Longitudinal Treatment of Adolescents with Depression and Inflammatory Bowel Disease

ERIC Educational Resources Information Center

Szigethy, Eva; Carpenter, Johanna; Baum, Emily; Kenney, Elyse; Baptista-Neto, Lourival; Beardslee, William R.; DeMaso, David Ray

2006-01-01

Objective: To assess longitudinal maintenance of improvements in depression, anxiety, global functioning, and physical health perception in 11 adolescents at 6 and 12 months following completion of manual-based cognitive-behavioral therapy. Method: Standardized instruments assessed follow-up changes in depression, anxiety, physical health, and…

Age-specific prevalence of HPV genotypes in cervical cytology samples with equivocal or low-grade lesions

PubMed Central

Brismar-Wendel, S; Froberg, M; Hjerpe, A; Andersson, S; Johansson, B

2009-01-01

Background: To define the spectrum of human papillomavirus (HPV) types and establish an age limit for triage HPV testing in atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL). Materials and methods: 343 liquid-based cytological samples from the population-based screening programme with minor abnormalities were subjected to HPV genotyping (Linear Array, Roche, Basel, Switzerland). Results: High-risk human papillomavirus (HR-HPV) was found in 71% of LSIL and 49% of ASCUS cases (P<0.001). High-risk human papillomavirus prevalence was age-dependent in LSIL (P=0.01), with decreasing prevalence until the age of 50 years, followed by a slight increase. Human papillomavirus type 16 was the most common HR-HPV, found in 23% of HPV-positive women. Human papillomavirus type 18 was the sixth most common, found in 9.9% (P<0.001). An age-dependent quadratic trend was observed for multiple infections (P=0.01) with a trough at about 42 years. The most common HR-HPV types to show a coinfection with HPV16 (clade 9) were HPV39 (28%), 45 (38%), and 59 (46%), belonging to HPV18 clade 7. The frequency of low-risk (LR) vs probable HR and HR-HPV also followed an age-dependent quadratic trend. Conclusions: After the age of 25 years, HR-HPV prevalence is similar in LSIL and ASCUS cases, motivating a low age limit for triage HPV testing. Multiple infections and LR/HR-HPV dominance are age-dependent. Genotyping in longitudinal design is needed to elucidate the importance of multiple infections in cancer progression and in cross-protection from vaccination. PMID:19623178

Aerodynamic preliminary analysis system. Part 1: Theory. [linearized potential theory

NASA Technical Reports Server (NTRS)

Bonner, E.; Clever, W.; Dunn, K.

1978-01-01

A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple non-planar surfaces of arbitrary planform and open or closed slender bodies of non-circular contour may be analyzed. Longitudinal and lateral-directional static and rotary derivative solutions may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

Tuberculous otitis media: a significant diagnostic challenge.

PubMed

Vaamonde, Pedro; Castro, Crisanto; García-Soto, Nicolas; Labella, Torcuato; Lozano, Ascensión

2004-06-01

This study was undertaken to revise the diagnostic characteristics of tuberculous otitis media (TOM), a disorder that is often diagnosed late, leading to delay in specific treatment. Retrospective study of a longitudinal series of 10 TOM patients over a 7-year period at an institutional referral center. Most patients showed intractable otorrhea, moderately severe hearing loss, and necrotic eardrums with granulation tissue and single perforations. Multiple perforations, facial palsy, and cervical adenopathies were rare (<10% of patients). CT generally showed soft tissue involvement of the middle ear without bone erosion. The most effective laboratory test microbiological culture of exudate (diagnostic efficacy 71%). Specific antibiotic treatment was effective in all cases. The diagnosis of TOM remains a significant challenge for otorhinolaryngologists. If there are strong clinical grounds for suspicion, standard laboratory tests for tuberculosis should be repeated even if initially negative.

The CogBIAS longitudinal study protocol: cognitive and genetic factors influencing psychological functioning in adolescence.

PubMed

Booth, Charlotte; Songco, Annabel; Parsons, Sam; Heathcote, Lauren; Vincent, John; Keers, Robert; Fox, Elaine

2017-12-29

Optimal psychological development is dependent upon a complex interplay between individual and situational factors. Investigating the development of these factors in adolescence will help to improve understanding of emotional vulnerability and resilience. The CogBIAS longitudinal study (CogBIAS-L-S) aims to combine cognitive and genetic approaches to investigate risk and protective factors associated with the development of mood and impulsivity-related outcomes in an adolescent sample. CogBIAS-L-S is a three-wave longitudinal study of typically developing adolescents conducted over 4 years, with data collection at age 12, 14 and 16. At each wave participants will undergo multiple assessments including a range of selective cognitive processing tasks (e.g. attention bias, interpretation bias, memory bias) and psychological self-report measures (e.g. anxiety, depression, resilience). Saliva samples will also be collected at the baseline assessment for genetic analyses. Multilevel statistical analyses will be performed to investigate the developmental trajectory of cognitive biases on psychological functioning, as well as the influence of genetic moderation on these relationships. CogBIAS-L-S represents the first longitudinal study to assess multiple cognitive biases across adolescent development and the largest study of its kind to collect genetic data. It therefore provides a unique opportunity to understand how genes and the environment influence the development and maintenance of cognitive biases and provide insight into risk and protective factors that may be key targets for intervention.

The Effect of State Medicaid Case-Mix Payment on Nursing Home Resident Acuity

PubMed Central

Feng, Zhanlian; Grabowski, David C; Intrator, Orna; Mor, Vincent

2006-01-01

Objective To examine the relationship between Medicaid case-mix payment and nursing home resident acuity. Data Sources Longitudinal Minimum Data Set (MDS) resident assessments from 1999 to 2002 and Online Survey Certification and Reporting (OSCAR) data from 1996 to 2002, for all freestanding nursing homes in the 48 contiguous U.S. states. Study Design We used a facility fixed-effects model to examine the effect of introducing state case-mix payment on changes in nursing home case-mix acuity. Facility acuity was measured by aggregating the nursing case-mix index (NCMI) from the MDS using the Resource Utilization Group (Version III) resident classification system, separately for new admits and long-stay residents, and by an OSCAR-derived index combining a range of activity of daily living dependencies and special treatment measures. Data Collection/Extraction Methods We followed facilities over the study period to create a longitudinal data file based on the MDS and OSCAR, respectively, and linked facilities with longitudinal data on state case-mix payment policies for the same period. Principal Findings Across three acuity measures and two data sources, we found that states shifting to case-mix payment increased nursing home acuity levels over the study period. Specifically, we observed a 2.5 percent increase in the average acuity of new admits and a 1.3 to 1.4 percent increase in the acuity of long-stay residents, following the introduction of case-mix payment. Conclusions The adoption of case-mix payment increased access to care for higher acuity Medicaid residents. PMID:16899009

The "Nursing Home Compare" measure of urinary/fecal incontinence: cross-sectional variation, stability over time, and the impact of case mix.

PubMed

Li, Yue; Schnelle, John; Spector, William D; Glance, Laurent G; Mukamel, Dana B

2010-02-01

To assess the impact of facility case mix on cross-sectional variations and short-term stability of the "Nursing Home Compare" incontinence quality measure (QM) and to determine whether multivariate risk adjustment can minimize such impacts. Retrospective analyses of the 2005 national minimum data set (MDS) that included approximately 600,000 long-term care residents in over 10,000 facilities in each quarterly sample. Mixed logistic regression was used to construct the risk-adjusted QM (nonshrinkage estimator). Facility-level ordinary least-squares models and adjusted R(2) were used to estimate the impact of case mix on cross-sectional and short-term longitudinal variations of currently published and risk-adjusted QMs. At least 50 percent of the cross-sectional variation and 25 percent of the short-term longitudinal variation of the published QM are explained by facility case mix. In contrast, the cross-sectional and short-term longitudinal variations of the risk-adjusted QM are much less susceptible to case-mix variations (adjusted R(2)<0.10), even for facilities with more extreme or more unstable outcome. Current "Nursing Home Compare" incontinence QM reflects considerable case-mix variations across facilities and over time, and therefore it may be biased. This issue can be largely addressed by multivariate risk adjustment using risk factors available in the MDS.

A longitudinal examination of the interrelationship of multiple health behaviors.

PubMed

deRuiter, Wayne K; Cairney, John; Leatherdale, Scott T; Faulkner, Guy E J

2014-09-01

Evaluating the interrelationship of health behaviors could assist in the development of effective public health interventions. Furthermore, the ability to identify cognitive mediators that may influence multiple behavioral changes requires evaluation. To evaluate covariation among health behaviors, specifically alcohol consumption, leisure-time physical activity, and smoking, and examine whether mastery acts as a mediating social-cognitive mechanism that facilitates multiple health behavior change in a longitudinal analysis. In 2010, secondary data analysis was conducted on the first seven cycles of the Canadian National Population Health Survey. Data collection began in 1994-1995 and has continued biennially. At the time of this analysis, only seven cycles of data (2006-2007) were available. Parallel process growth curve models were used to analyze covariation between health behaviors and the potential mediating effects of perceived mastery. Increases in leisure-time physical activity were associated with reductions in tobacco use, whereas declines in alcohol consumption were associated with decreases in tobacco use. Covariation between alcohol consumption and leisure-time physical activity did not reach statistical significance. For the most part, mastery was unsuccessful in mediating the interrelationship of multiple behavioral changes. Health behaviors are not independent but rather interrelated. In order to optimize limited prevention resources, these results suggest that population-level intervention efforts targeting multiple modifiable behavioral risk factors may not need to occur simultaneously. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

A Longitudinal Test of the Demand–Control Model Using Specific Job Demands and Specific Job Control

PubMed Central

van Vegchel, Natasja; Shimazu, Akihito; Schaufeli, Wilmar; Dormann, Christian

2010-01-01

Background Supportive studies of the demand–control (DC) model were more likely to measure specific demands combined with a corresponding aspect of control. Purpose A longitudinal test of Karasek’s (Adm Sci Q. 24:285–308, 1) job strain hypothesis including specific measures of job demands and job control, and both self-report and objectively recorded well-being. Method Job strain hypothesis was tested among 267 health care employees from a two-wave Dutch panel survey with a 2-year time lag. Results Significant demand/control interactions were found for mental and emotional demands, but not for physical demands. The association between job demands and job satisfaction was positive in case of high job control, whereas this association was negative in case of low job control. In addition, the relation between job demands and psychosomatic health symptoms/sickness absence was negative in case of high job control and positive in case of low control. Conclusion Longitudinal support was found for the core assumption of the DC model with specific measures of job demands and job control as well as self-report and objectively recorded well-being. PMID:20195810

Investigation of 2-stage meta-analysis methods for joint longitudinal and time-to-event data through simulation and real data application.

PubMed

Sudell, Maria; Tudur Smith, Catrin; Gueyffier, François; Kolamunnage-Dona, Ruwanthi

2018-04-15

Joint modelling of longitudinal and time-to-event data is often preferred over separate longitudinal or time-to-event analyses as it can account for study dropout, error in longitudinally measured covariates, and correlation between longitudinal and time-to-event outcomes. The joint modelling literature focuses mainly on the analysis of single studies with no methods currently available for the meta-analysis of joint model estimates from multiple studies. We propose a 2-stage method for meta-analysis of joint model estimates. These methods are applied to the INDANA dataset to combine joint model estimates of systolic blood pressure with time to death, time to myocardial infarction, and time to stroke. Results are compared to meta-analyses of separate longitudinal or time-to-event models. A simulation study is conducted to contrast separate versus joint analyses over a range of scenarios. Using the real dataset, similar results were obtained by using the separate and joint analyses. However, the simulation study indicated a benefit of use of joint rather than separate methods in a meta-analytic setting where association exists between the longitudinal and time-to-event outcomes. Where evidence of association between longitudinal and time-to-event outcomes exists, results from joint models over standalone analyses should be pooled in 2-stage meta-analyses. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

Myalgic Encephalomyelitis: Symptoms and Biomarkers

PubMed Central

Jasona, Leonard A.; Zinn, Marcie L.; Zinn, Mark A.

2015-01-01

Myalgic Encephalomyelitis (ME) continues to cause significant morbidity worldwide with an estimated one million cases in the United States. Hurdles to establishing consensus to achieve accurate evaluation of patients with ME continue, fueled by poor agreement about case definitions, slow progress in development of standardized diagnostic approaches, and issues surrounding research priorities. Because there are other medical problems, such as early MS and Parkinson’s Disease, which have some similar clinical presentations, it is critical to accurately diagnose ME to make a differential diagnosis. In this article, we explore and summarize advances in the physiological and neurological approaches to understanding, diagnosing, and treating ME. We identify key areas and approaches to elucidate the core and secondary symptom clusters in ME so as to provide some practical suggestions in evaluation of ME for clinicians and researchers. This review, therefore, represents a synthesis of key discussions in the literature, and has important implications for a better understanding of ME, its biological markers, and diagnostic criteria. There is a clear need for more longitudinal studies in this area with larger data sets, which correct for multiple testing. PMID:26411464

From ICT Coordination to ICT Integration: A Longitudinal Case Study

ERIC Educational Resources Information Center

Tondeur, J.; Cooper, M.; Newhouse, C. P.

2010-01-01

This study utilizes a school-improvement perspective to examine the role of curriculum coordination in the integration of information and communication technologies (ICT) into primary schools. The nature and impact of this role is examined in seven primary schools in Australia. These seven schools were drawn from a longitudinal intervention that…

A Longitudinal Analysis of Students' Motives for Communicating with Their Instructors

ERIC Educational Resources Information Center

Myers, Scott A.

2017-01-01

This study utilized the longitudinal survey research design using students' motives to communicate with their instructors as a test case. Participants were 282 undergraduate students enrolled in introductory communication courses at a large Mid-Atlantic university who completed the Student Communication Motives scale at three points (Time 1:…

The effect of the masses of the controls on the longitudinal stability with free elevator. Part I

NASA Technical Reports Server (NTRS)

Schmidt, Rudolf

1939-01-01

In the present report, aerodynamic relations under the effect of the weight moments are investigated, and an example given of the computation of the stability for a practical case. Later, the effects of the masses of the controls on the dynamic longitudinal stability will be considered.

South Carolina Case Study: Building a Student-Level Longitudinal Data System

ERIC Educational Resources Information Center

Kugle, Cherry; Smith, Nancy

2007-01-01

The Data Quality Campaign is a national, collaborative effort to encourage and support state policymakers to improve the collection, availability and use of high-quality education data and to implement state longitudinal data systems to improve student achievement. The campaign aims to provide tools and resources that will assist state development…

"A Writer More than . . . A Child": A Longitudinal Study Examining Adolescent Writer Identity

ERIC Educational Resources Information Center

Lammers, Jayne C.; Marsh, Valerie L.

2018-01-01

This article reconsiders theoretical claims of identity fluidity, stability, and agency through a longitudinal case study investigating one adolescent's writing over time and across spaces. Qualitative data spanning her four years of high school were collected and analyzed using a grounded theory approach with literacy-and-identity theory…

Louisiana Case Study: Building a Student-Level Longitudinal Data System

ERIC Educational Resources Information Center

Kugle, Cherry; Smith, Nancy

2008-01-01

The Data Quality Campaign is a national, collaborative effort to encourage and support state policymakers to improve the collection, availability and use of high-quality education data and to implement state longitudinal data systems to improve student achievement. The campaign aims to provide tools and resources that will assist state development…

Longitudinal Examination of Optimism, Personal Self-Efficacy and Student Well-Being: A Path Analysis

ERIC Educational Resources Information Center

Phan, Huy P.

2016-01-01

The present longitudinal study, based on existing theoretical tenets, explored a conceptual model that depicted four major orientations: optimism, self-efficacy, and academic well-being. An important question for consideration, in this case, involved the testing of different untested trajectories that could explain and predict individuals'…

MODELING LEFT-TRUNCATED AND RIGHT-CENSORED SURVIVAL DATA WITH LONGITUDINAL COVARIATES

PubMed Central

Su, Yu-Ru; Wang, Jane-Ling

2018-01-01

There is a surge in medical follow-up studies that include longitudinal covariates in the modeling of survival data. So far, the focus has been largely on right censored survival data. We consider survival data that are subject to both left truncation and right censoring. Left truncation is well known to produce biased sample. The sampling bias issue has been resolved in the literature for the case which involves baseline or time-varying covariates that are observable. The problem remains open however for the important case where longitudinal covariates are present in survival models. A joint likelihood approach has been shown in the literature to provide an effective way to overcome those difficulties for right censored data, but this approach faces substantial additional challenges in the presence of left truncation. Here we thus propose an alternative likelihood to overcome these difficulties and show that the regression coefficient in the survival component can be estimated unbiasedly and efficiently. Issues about the bias for the longitudinal component are discussed. The new approach is illustrated numerically through simulations and data from a multi-center AIDS cohort study. PMID:29479122

Interviewer effects on non-response propensity in longitudinal surveys: a multilevel modelling approach

PubMed Central

Vassallo, Rebecca; Durrant, Gabriele B; Smith, Peter W F; Goldstein, Harvey

2015-01-01

The paper investigates two different multilevel approaches, the multilevel cross-classified and the multiple-membership models, for the analysis of interviewer effects on wave non-response in longitudinal surveys. The models proposed incorporate both interviewer and area effects to account for the non-hierarchical structure, the influence of potentially more than one interviewer across waves and possible confounding of area and interviewer effects arising from the non-random allocation of interviewers across areas. The methods are compared by using a data set: the UK Family and Children Survey. PMID:25598587

Neural-Based Compensation of Nonlinearities in an Airplane Longitudinal Model with Dynamic-Inversion Control

PubMed Central

Li, YuHui; Jin, FeiTeng

2017-01-01

The inversion design approach is a very useful tool for the complex multiple-input-multiple-output nonlinear systems to implement the decoupling control goal, such as the airplane model and spacecraft model. In this work, the flight control law is proposed using the neural-based inversion design method associated with the nonlinear compensation for a general longitudinal model of the airplane. First, the nonlinear mathematic model is converted to the equivalent linear model based on the feedback linearization theory. Then, the flight control law integrated with this inversion model is developed to stabilize the nonlinear system and relieve the coupling effect. Afterwards, the inversion control combined with the neural network and nonlinear portion is presented to improve the transient performance and attenuate the uncertain effects on both external disturbances and model errors. Finally, the simulation results demonstrate the effectiveness of this controller. PMID:29410680

Transverse versus Longitudinal Incisions for Femoral Artery Exposure in Treating Patients with Peripheral Vascular Disease.

PubMed

Parikh, Punam P; Rubio, Gustavo A; Patel, Kunal; Gupta, Kapil; Jones, Keith; Rey, Jorge; Robinson, Handel

2018-02-01

This study evaluates differences in wound complication rate when transverse versus longitudinal incision is utilized to expose femoral vessels in managing patients with peripheral vascular disease. A retrospective review from 2013 to 2015 was conducted of 150 patients undergoing 156 lower extremity revascularizations with femoral artery exposure through a groin incision. Patients were stratified into 2 groups, transverse versus longitudinal groin incision. Data were reviewed for 3 surgeons that utilize either transverse or longitudinal groin incision in patients undergoing common or iliofemoral endarterectomies, or where femoral artery was used as inflow and/or outflow vessel for limb revascularization. Each group had a comparative outcomes analysis based on incision type. The primary outcome was wound complication, defined as any wound infection, lymphocele, hematoma, dehiscence, pseudoaneurysm, or necrosis. Other outcomes studied included unplanned return to operating room for wound complication, wound vacuum therapy, and soft-tissue flap closure. Data were analyzed using 2-tailed chi-squared test and Student's t-test. Patients in the transverse (n = 85 cases) versus longitudinal (n = 71 cases) cohorts were similar in relation to demographics and comorbidities. Overall mean follow-up was 220 days. Patients with a transverse as compared to longitudinal incision had a significantly lower overall wound complication rate, 7% vs. 42%, respectively (P < 0.001). Furthermore, transverse incisions were associated with lower incidence of unplanned return to the operating room to manage wound complications than patients with a longitudinal incision (5% vs. 23%, respectively; P < 0.001). Transverse versus longitudinal incisions were also associated with significantly lower need for wound vacuum therapy (6% vs. 15%, respectively; P < 0.05) and muscle flap closure (0% vs. 13%, respectively; P < 0.001) for wound complications. Transverse groin incisions for femoral artery exposure may offer a lower risk of wound complications for open procedures as compared to a longitudinal incision. While longitudinal incisions may have higher wound complication rates, incisional approach is contingent on anatomical circumstance and treated disease pattern. Patients should undergo appropriate preoperative counseling regarding wound healing in preparation for limb revascularization. Copyright © 2017 Elsevier Inc. All rights reserved.

Making an unknown unknown a known unknown: Missing data in longitudinal neuroimaging studies.

PubMed

Matta, Tyler H; Flournoy, John C; Byrne, Michelle L

2017-10-28

The analysis of longitudinal neuroimaging data within the massively univariate framework provides the opportunity to study empirical questions about neurodevelopment. Missing outcome data are an all-to-common feature of any longitudinal study, a feature that, if handled improperly, can reduce statistical power and lead to biased parameter estimates. The goal of this paper is to provide conceptual clarity of the issues and non-issues that arise from analyzing incomplete data in longitudinal studies with particular focus on neuroimaging data. This paper begins with a review of the hierarchy of missing data mechanisms and their relationship to likelihood-based methods, a review that is necessary not just for likelihood-based methods, but also for multiple-imputation methods. Next, the paper provides a series of simulation studies with designs common in longitudinal neuroimaging studies to help illustrate missing data concepts regardless of interpretation. Finally, two applied examples are used to demonstrate the sensitivity of inferences under different missing data assumptions and how this may change the substantive interpretation. The paper concludes with a set of guidelines for analyzing incomplete longitudinal data that can improve the validity of research findings in developmental neuroimaging research. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Developing longitudinal qualitative designs: lessons learned and recommendations for health services research.

PubMed

Calman, Lynn; Brunton, Lisa; Molassiotis, Alex

2013-02-06

Longitudinal qualitative methods are becoming increasingly used in the health service research, but the method and challenges particular to health care settings are not well described in the literature.We reflect on the strategies used in a longitudinal qualitative study to explore the experience of symptoms in cancer patients and their carers, following participants from diagnosis for twelve months; we highlight ethical, practical, theoretical and methodological issues that need to be considered and addressed from the outset of a longitudinal qualitative study. Key considerations in undertaking longitudinal qualitative projects in health research, include the use of theory, utilizing multiple methods of analysis and giving consideration to the practical and ethical issues at an early stage. These can include issues of time and timing; data collection processes; changing the topic guide over time; recruitment considerations; retention of staff; issues around confidentiality; effects of project on staff and patients, and analyzing data within and across time. As longitudinal qualitative methods are becoming increasingly used in health services research, the methodological and practical challenges particular to health care settings need more robust approaches and conceptual improvement. We provide recommendations for the use of such designs. We have a particular focus on cancer patients, so this paper will have particular relevance for researchers interested in chronic and life limiting conditions.

Assessment of the effect of population and diary sampling methods on estimation of school-age children exposure to fine particles.

PubMed

Che, W W; Frey, H Christopher; Lau, Alexis K H

2014-12-01

Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified-random and random-random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov-chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM2.5 ) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m(3) for simulated children using the stratified population sampling method, and 12.2 μg/m(3) using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m(3) due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern. © 2014 Society for Risk Analysis.

Insights on the effectiveness of reward schemes from 10-year longitudinal case studies in 2 Italian regions.

PubMed

Vainieri, Milena; Lungu, Daniel Adrian; Nuti, Sabina

2018-01-30

Pay for performance (P4P) programs have been widely analysed in literature, and the results regarding their impact on performance are mixed. Moreover, in the real-life setting, reward schemes are designed combining multiple elements altogether, yet, it is not clear what happens when they are applied using different combinations. To provide insights on how P4P programs are influenced by 5 key elements: whom, what, how, how many targets, and how much to reward. A qualitative longitudinal analysis of 10 years of P4P reward schemes adopted by the regional administrations of Tuscany and Lombardy (Italy) was conducted. The effects of the P4P features on performance are discussed considering both overall and specific indicators. Both regions applied financial reward schemes for General Managers by linking the variable pay to performance. While Tuscany maintained a relatively stable financial incentive design and governance tools, Lombardy changed some elements of the design and introduced, in 2012, a P4P program aimed to reward the providers. The main differences between the 2 cases regard the number of targets (how many), the type (what), and the method applied to set targets (how). Considering the overall performance obtained by the 2 regions, it seems that whom, how, and how much to reward are not relevant in the success of P4P programs; instead, the number (how many) and the type (what) of targets set may influence the performance improvement processes driven by financial reward schemes. © 2018 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd.

E-cigarettes and equity: a systematic review of differences in awareness and use between sociodemographic groups

PubMed Central

Hartwell, Greg; Thomas, Sian; Egan, Matt; Gilmore, Anna; Petticrew, Mark

2017-01-01

Objective To assess whether electronic cigarette (e-cigarette) awareness, ‘ever use’ and current use vary significantly between different sociodemographic groups. Design Systematic review. Data sources Published and unpublished reports identified by searching seven electronic databases (PubMed, MEDLINE, Web of Science, EMBASE, Global Health, PsycINFO, CINAHL Plus) and grey literature sources. Study selection Systematic search for and appraisal of cross-sectional or longitudinal studies that assessed e-cigarette awareness, ‘ever use’ or current use, and included subgroup analysis of 1 or more PROGRESS Plus sociodemographic groups. No geographical or time restrictions imposed. Assessment by multiple reviewers, with 17% of full articles screened meeting the selection criteria. Data extraction Data extracted and checked by multiple reviewers, with quality assessed using an adapted tool developed by the Joanna Briggs Institute. Data synthesis Results of narrative synthesis suggest broadly that awareness, ‘ever use’ and current use of e-cigarettes may be particularly prevalent among older adolescents and younger adults, males, people of white ethnicity and—particularly in the case of awareness and ‘ever use’—those of intermediate or high levels of education. In some cases, results also varied within and between countries. Conclusions E-cigarette awareness, ‘ever use’ and current use appear to be patterned by a number of sociodemographic factors which vary between different countries and subnational localities. Care will therefore be required to ensure neither the potential benefits nor the potential risks of e-cigarettes exacerbate existing health inequalities. PMID:28003324

Mental health of adolescents before and after the death of a parent or sibling.

PubMed

Stikkelbroek, Yvonne; Bodden, Denise H M; Reitz, Ellen; Vollebergh, Wilma A M; van Baar, Anneloes L

2016-01-01

The death of a parent or sibling (family bereavement) is associated with mental health problems in approximately, 25 % of the affected children. However, it is still unknown whether mental health problems of family-bereaved adolescents are predicted by pre-existing mental health problems, pre-loss family functioning, or multiple bereavements. In this study, a prospective longitudinal assessment of change in mental health following bereavement was done in a large representative sample from the 'Tracking Adolescents Individual Lives Survey' (TRAILS). This is a four-wave prospective cohort study of Dutch adolescents (n = 2230) of whom 131 (5.9 %) had experienced family bereavement at the last wave (T4). Family-bereaved adolescents reported more internalizing problems, within 2 years after family bereavement, compared to the non-bereaved peers, while taking into account the level of internalizing problems before the bereavement. A clinically relevant finding was that 22 % new cases were found in family-bereaved, in comparison to 5.5 % new cases in non-bereaved. Low SES predicted more internalizing problems in family-bereaved but not in non-bereaved adolescents. Family functioning, reported by the adolescent, did not predict mental health problems within 2 years. Multiple family bereavements predicted fewer externalizing problems. In conclusion, internalizing problems increase in adolescents after family bereavement in comparison to non-bereaved and these can be predicted by pre-loss factors. Awareness among professionals regarding the risks for aggravation of mental health problems after family loss is needed.

A Non-Intrusive Pressure Sensor by Detecting Multiple Longitudinal Waves

PubMed Central

Zhou, Hongliang; Lin, Weibin; Ge, Xiaocheng; Zhou, Jian

2016-01-01

Pressure vessels are widely used in industrial fields, and some of them are safety-critical components in the system—for example, those which contain flammable or explosive material. Therefore, the pressure of these vessels becomes one of the critical measurements for operational management. In the paper, we introduce a new approach to the design of non-intrusive pressure sensors, based on ultrasonic waves. The model of this sensor is built based upon the travel-time change of the critically refracted longitudinal wave (LCR wave) and the reflected longitudinal waves with the pressure. To evaluate the model, experiments are carried out to compare the proposed model with other existing models. The results show that the proposed model can improve the accuracy compared to models based on a single wave. PMID:27527183

Estimating onset time from longitudinal and cross-sectional data with an application to estimating gestational age from longitudinal maternal anthropometry during pregnancy and neonatal anthropometry at birth.

PubMed

Ortega-Villa, Ana Maria; Grantz, Katherine L; Albert, Paul S

2018-06-01

Determining the date of conception is important for estimating gestational age and monitoring whether the fetus and mother are on track in their development and pregnancy. Various methods based on ultrasound have been proposed for dating a pregnancy in high resource countries. However, such techniques may not be available in under-resourced countries. We develop a shared random parameter model for estimating the date of conception using longitudinal assessment of multiple maternal anthropometry and cross-sectional neonatal anthropometry. The methodology is evaluated with a training-test set paradigm as well as with simulations to examine the robustness of the method to model misspecification. We illustrate this new methodology with data from the NICHD Fetal Growth Studies.

Analysis of the enablers of capacities to produce primary health care-based reforms in Latin America: a multiple case study

PubMed Central

Báscolo, Ernesto Pablo; Yavich, Natalia; Denis, Jean-Louis

2016-01-01

Abstract Background Primary health care (PHC)-based reforms have had different results in Latin America. Little attention has been paid to the enablers of collective action capacities required to produce a comprehensive PHC approach. Objective To analyse the enablers of collective action capacities to transform health systems towards a comprehensive PHC approach in Latin American PHC-based reforms. Methods We conducted a longitudinal, retrospective case study of three municipal PHC-based reforms in Bolivia and Argentina. We used multiple data sources and methodologies: document review; interviews with policymakers, managers and practitioners; and household and services surveys. We used temporal bracketing to analyse how the dynamic of interaction between the institutional reform process and the collective action characteristics enabled or hindered the enablers of collective action capacities required to produce the envisioned changes. Results The institutional structuring dynamics and collective action capacities were different in each case. In Cochabamba, there was an ‘interrupted’ structuring process that achieved the establishment of a primary level with a selective PHC approach. In Vicente López, there was a ‘path-dependency’ structuring process that permitted the consolidation of a ‘primary care’ approach, but with limited influence in hospitals. In Rosario, there was a ‘dialectic’ structuring process that favoured the development of the capacities needed to consolidate a comprehensive PHC approach that permeates the entire system. Conclusion The institutional change processes achieved the development of a primary health care level with different degrees of consolidation and system-wide influence given how the characteristics of each collective action enabled or hindered the ‘structuring’ processes. PMID:27209640

Hairline fractures following volar plating of the distal radius: a recently recognized hardware-related complication.

PubMed

Otremski, Hila; Dolkart, Oleg; Atlan, Franck; Hutt, Dan; Segev, Elad; Pritsch, Tamir; Rosenblatt, Yishai

2018-06-01

Intraoperative hairline longitudinal fractures were recently reported in association with distal radius volar plating. Our aim was to further analyze this newly described complication. A retrospective radiographic and chart review was performed on 225 patients who underwent distal radius plating between June 2013 and June 2015. The Acu-Loc/Acu-Loc2© plating system (Acumed, Hillsboro, OR, USA) was used in 208 cases, and the VariAx© plating system (Stryker, Kalamazoo, MI, USA) was used in 17 cases. Three independent reviewers performed a blind evaluation of all relevant radiographs for the occurrence of longitudinal fractures around the plate, and validity was considered only when there was agreement among all three of them. Hairline longitudinal fractures were identified in 57 cases (25%), 55 with the Acu-Loc/Acu-Loc2© system and 2 with the VariAx© system. All fractures occurred with volar plating. Fracture occurrence was associated with age over 59 years, female gender, extra-articular fractures, and the use of Hexalobe screws (Acu-Loc/Acu-Loc2© system). We believe that the source of fracture occurrence lies within the screw design and that better screw design and possibly tapping in patients at risk may reduce the occurrence of intraoperative hairline longitudinal fractures. Further clinical and biomechanical research is needed to better understand this newly reported complication.

Exploring Empirical Rank-Frequency Distributions Longitudinally through a Simple Stochastic Process

PubMed Central

Finley, Benjamin J.; Kilkki, Kalevi

2014-01-01

The frequent appearance of empirical rank-frequency laws, such as Zipf’s law, in a wide range of domains reinforces the importance of understanding and modeling these laws and rank-frequency distributions in general. In this spirit, we utilize a simple stochastic cascade process to simulate several empirical rank-frequency distributions longitudinally. We focus especially on limiting the process’s complexity to increase accessibility for non-experts in mathematics. The process provides a good fit for many empirical distributions because the stochastic multiplicative nature of the process leads to an often observed concave rank-frequency distribution (on a log-log scale) and the finiteness of the cascade replicates real-world finite size effects. Furthermore, we show that repeated trials of the process can roughly simulate the longitudinal variation of empirical ranks. However, we find that the empirical variation is often less that the average simulated process variation, likely due to longitudinal dependencies in the empirical datasets. Finally, we discuss the process limitations and practical applications. PMID:24755621

A Joint Model for Longitudinal Measurements and Survival Data in the Presence of Multiple Failure Types

PubMed Central

Elashoff, Robert M.; Li, Gang; Li, Ning

2009-01-01

Summary In this article we study a joint model for longitudinal measurements and competing risks survival data. Our joint model provides a flexible approach to handle possible nonignorable missing data in the longitudinal measurements due to dropout. It is also an extension of previous joint models with a single failure type, offering a possible way to model informatively censored events as a competing risk. Our model consists of a linear mixed effects submodel for the longitudinal outcome and a proportional cause-specific hazards frailty submodel (Prentice et al., 1978, Biometrics 34, 541-554) for the competing risks survival data, linked together by some latent random effects. We propose to obtain the maximum likelihood estimates of the parameters by an expectation maximization (EM) algorithm and estimate their standard errors using a profile likelihood method. The developed method works well in our simulation studies and is applied to a clinical trial for the scleroderma lung disease. PMID:18162112

Exploring empirical rank-frequency distributions longitudinally through a simple stochastic process.

PubMed

Finley, Benjamin J; Kilkki, Kalevi

2014-01-01

The frequent appearance of empirical rank-frequency laws, such as Zipf's law, in a wide range of domains reinforces the importance of understanding and modeling these laws and rank-frequency distributions in general. In this spirit, we utilize a simple stochastic cascade process to simulate several empirical rank-frequency distributions longitudinally. We focus especially on limiting the process's complexity to increase accessibility for non-experts in mathematics. The process provides a good fit for many empirical distributions because the stochastic multiplicative nature of the process leads to an often observed concave rank-frequency distribution (on a log-log scale) and the finiteness of the cascade replicates real-world finite size effects. Furthermore, we show that repeated trials of the process can roughly simulate the longitudinal variation of empirical ranks. However, we find that the empirical variation is often less that the average simulated process variation, likely due to longitudinal dependencies in the empirical datasets. Finally, we discuss the process limitations and practical applications.

Simulation and characterization of silicon-based 0.5-MHz ultrasonic nozzles

NASA Astrophysics Data System (ADS)

Song, Y. L.; Tsai, S. C.; Chen, W. J.; Chou, Y. F.; Tseng, T. K.; Tsai, C. S.

2004-01-01

This paper compares the simulation results with the experimental results of impedance analysis and longitudinal vibration measurement of micro-fabricated 0.5 MHz silicon-based ultrasonic nozzles. Impedance analysis serves as a good diagnostic tool for evaluation of longitudinal vibration of the nozzles. Each nozzle is made of a piezoelectric drive section and a silicon-resonator consisting of multiple Fourier horns each with half wavelength design and twice amplitude magnification. The experimental results verified the simulation prediction of one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude gain at the nozzle tip increases as the number of Fourier horns (n) increases in good agreement with the theoretical value of 2n. Using this design, very high vibration amplitude at the nozzle tip can be achieved with no reduction in the tip cross sectional area. Therefore, the required electric drive power should be drastically reduced, decreasing the likelihood of transducer failure in ultrasonic atomization.

Longitudinal performance of plasma neurofilament light and tau in professional fighters: The Professional Fighters Brain Health Study.

PubMed

Bernick, Charles; Zetterberg, Henrik; Shan, Guogen; Banks, Sarah; Blennow, Kaj

2018-04-02

The objective of this study is to evaluate longitudinal change in plasma neurofilament light (NF-L) and tau levels in relationship to clinical and radiological measures in professional fighters. Participants (active and retired professional fighters and control group) underwent annual blood sampling, 3 Tesla MRI brain imaging, computerized cognitive testing, and assessment of exposure to head trauma. Plasma tau and NF-L concentrations were measured using Simoa assays. Multiple linear regression models were used to compare the difference across groups in regard to baseline measurements, while mixed linear models was used for the longitudinal data with multiple measurements for each participant. Plasma samples were available on 471 participants. Baseline NF-L measures differed across groups (F_3,393=6.99, p=0.0001), with the active boxers having the highest levels. Higher NF-L levels at baseline were correlated with lower baseline MRI regional volumes and lower cognitive scores. The number of sparring rounds completed by the active fighters was correlated with NF-L (95% CI 0.0116-0.4053, p=0.0381), but not tau, levels. Among 126 subjects having multiple yearly samples, there was a significant difference in average yearly percentage change in tau across groups (F_3,83=3.87, p=0.0121).). We conclude that plasma NF-L and tau behave differently in a group of active and retired fighters; NF-L better reflects acute exposure whereas the role of plasma tau levels in signifying chronic change in brain structure over time requires further study.

Temporally-Constrained Group Sparse Learning for Longitudinal Data Analysis in Alzheimer’s Disease

PubMed Central

Jie, Biao; Liu, Mingxia; Liu, Jun

2016-01-01

Sparse learning has been widely investigated for analysis of brain images to assist the diagnosis of Alzheimer’s disease (AD) and its prodromal stage, i.e., mild cognitive impairment (MCI). However, most existing sparse learning-based studies only adopt cross-sectional analysis methods, where the sparse model is learned using data from a single time-point. Actually, multiple time-points of data are often available in brain imaging applications, which can be used in some longitudinal analysis methods to better uncover the disease progression patterns. Accordingly, in this paper we propose a novel temporally-constrained group sparse learning method aiming for longitudinal analysis with multiple time-points of data. Specifically, we learn a sparse linear regression model by using the imaging data from multiple time-points, where a group regularization term is first employed to group the weights for the same brain region across different time-points together. Furthermore, to reflect the smooth changes between data derived from adjacent time-points, we incorporate two smoothness regularization terms into the objective function, i.e., one fused smoothness term which requires that the differences between two successive weight vectors from adjacent time-points should be small, and another output smoothness term which requires the differences between outputs of two successive models from adjacent time-points should also be small. We develop an efficient optimization algorithm to solve the proposed objective function. Experimental results on ADNI database demonstrate that, compared with conventional sparse learning-based methods, our proposed method can achieve improved regression performance and also help in discovering disease-related biomarkers. PMID:27093313

Accounting for disease modifying therapy in models of clinical progression in multiple sclerosis.

PubMed

Healy, Brian C; Engler, David; Gholipour, Taha; Weiner, Howard; Bakshi, Rohit; Chitnis, Tanuja

2011-04-15

Identifying predictors of clinical progression in patients with relapsing-remitting multiple sclerosis (RRMS) is complicated in the era of disease modifying therapy (DMT) because patients follow many different DMT regimens. To investigate predictors of progression in a treated RRMS sample, a cohort of RRMS patients was prospectively followed in the Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women's Hospital (CLIMB). Enrollment criteria were exposure to either interferon-β (IFN-β, n=164) or glatiramer acetate (GA, n=114) for at least 6 months prior to study entry. Baseline demographic and clinical features were used as candidate predictors of longitudinal clinical change on the Expanded Disability Status Scale (EDSS). We compared three approaches to account for DMT effects in statistical modeling. In all approaches, we analyzed all patients together and stratified based on baseline DMT. Model 1 used all available longitudinal EDSS scores, even those after on-study DMT changes. Model 2 used only clinical observations prior to changing DMT. Model 3 used causal statistical models to identify predictors of clinical change. When all patients were considered using Model 1, patients with a motor symptom as the first relapse had significantly larger change in EDSS scores during follow-up (p=0.04); none of the other clinical or demographic variables significantly predicted change. In Models 2 and 3, results were generally unchanged. DMT modeling choice had a modest impact on the variables classified as predictors of EDSS score change. Importantly, however, interpretation of these predictors is dependent upon modeling choice. Copyright © 2011 Elsevier B.V. All rights reserved.

Large deep neural networks for MS lesion segmentation

NASA Astrophysics Data System (ADS)

Prieto, Juan C.; Cavallari, Michele; Palotai, Miklos; Morales Pinzon, Alfredo; Egorova, Svetlana; Styner, Martin; Guttmann, Charles R. G.

2017-02-01

Multiple sclerosis (MS) is a multi-factorial autoimmune disorder, characterized by spatial and temporal dissemination of brain lesions that are visible in T2-weighted and Proton Density (PD) MRI. Assessment of lesion burden and is useful for monitoring the course of the disease, and assessing correlates of clinical outcomes. Although there are established semi-automated methods to measure lesion volume, most of them require human interaction and editing, which are time consuming and limits the ability to analyze large sets of data with high accuracy. The primary objective of this work is to improve existing segmentation algorithms and accelerate the time consuming operation of identifying and validating MS lesions. In this paper, a Deep Neural Network for MS Lesion Segmentation is implemented. The MS lesion samples are extracted from the Partners Comprehensive Longitudinal Investigation of Multiple Sclerosis (CLIMB) study. A set of 900 subjects with T2, PD and a manually corrected label map images were used to train a Deep Neural Network and identify MS lesions. Initial tests using this network achieved a 90% accuracy rate. A secondary goal was to enable this data repository for big data analysis by using this algorithm to segment the remaining cases available in the CLIMB repository.

Longitudinal Neuroimaging Hippocampal Markers for Diagnosing Alzheimer's Disease.

PubMed

Platero, Carlos; Lin, Lin; Tobar, M Carmen

2018-05-21

Hippocampal atrophy measures from magnetic resonance imaging (MRI) are powerful tools for monitoring Alzheimer's disease (AD) progression. In this paper, we introduce a longitudinal image analysis framework based on robust registration and simultaneous hippocampal segmentation and longitudinal marker classification of brain MRI of an arbitrary number of time points. The framework comprises two innovative parts: a longitudinal segmentation and a longitudinal classification step. The results show that both steps of the longitudinal pipeline improved the reliability and the accuracy of the discrimination between clinical groups. We introduce a novel approach to the joint segmentation of the hippocampus across multiple time points; this approach is based on graph cuts of longitudinal MRI scans with constraints on hippocampal atrophy and supported by atlases. Furthermore, we use linear mixed effect (LME) modeling for differential diagnosis between clinical groups. The classifiers are trained from the average residue between the longitudinal marker of the subjects and the LME model. In our experiments, we analyzed MRI-derived longitudinal hippocampal markers from two publicly available datasets (Alzheimer's Disease Neuroimaging Initiative, ADNI and Minimal Interval Resonance Imaging in Alzheimer's Disease, MIRIAD). In test/retest reliability experiments, the proposed method yielded lower volume errors and significantly higher dice overlaps than the cross-sectional approach (volume errors: 1.55% vs 0.8%; dice overlaps: 0.945 vs 0.975). To diagnose AD, the discrimination ability of our proposal gave an area under the receiver operating characteristic (ROC) curve (AUC) [Formula: see text] 0.947 for the control vs AD, AUC [Formula: see text] 0.720 for mild cognitive impairment (MCI) vs AD, and AUC [Formula: see text] 0.805 for the control vs MCI.

The Pre-Incubator: A Longitudinal Study of 10 Years of University Pre-Incubation in Wales

ERIC Educational Resources Information Center

Voisey, Pamela; Jones, Paul; Thomas, Brychan

2013-01-01

This paper describes a longitudinal study of over 10 years of university pre-incubation in Wales, using case studies of incubated businesses to track their performance since 2001. Surviving "graduated" businesses were investigated and quantitative and qualitative data were gathered to profile the current status of these businesses and…

Educational Subculture and Dropping out in Higher Education: A Longitudinal Case Study

ERIC Educational Resources Information Center

Venuleo, C.; Mossi, P.; Salvatore, S.

2016-01-01

The paper tests longitudinally the hypothesis that educational subcultures in terms of which students interpret their role and their educational setting affect the probability of dropping out of higher education. A logistic regression model was performed to predict drop out at the beginning of the second academic year for the 823 freshmen of a…

Gifted Girls and Nonmathematical Aspirations: A Longitudinal Case Study of Two Gifted Korean Girls

ERIC Educational Resources Information Center

Lee, Kyeong Hwa; Sriraman, Bharath

2012-01-01

In this longitudinal study of two gifted Korean girls, experiences with early admittance into a gifted program are charted alongside their family and societal experiences that ultimately influenced their career choices in nonmathematical fields. The 8-year-long qualitative study involved extensive interviews with the two gifted girls and their…

WISC-R Verbal and Performance IQ Discrepancy in an Unselected Cohort: Clinical Significance and Longitudinal Stability.

ERIC Educational Resources Information Center

Moffitt, Terrie E.; Silva, P. A.

1987-01-01

Examined children whose Wechsler Intelligence Scale for Children-Revised (WISC-R) verbal and performance Intelligence Quotient discrepancies placed them beyond the 90th percentile. Longitudinal study showed 23 percent of the discrepant cases to be discrepant at two or more ages. Studied frequency of perinatal difficulties, early childhood…

Variability in Fundamental Frequency during Speech in Prodromal and Incipient Parkinson's Disease: A Longitudinal Case Study

ERIC Educational Resources Information Center

Harel, Brian; Cannizzaro, Michael; Snyder, Peter J.

2004-01-01

Nearly two centuries ago, Parkinson (1817) first observed that a particular pattern of speech changes occur in patients with idiopathic Parkinson's disease (PD). Numerous studies have documented these changes using a wide variety of acoustic measures, and yet few studies have attempted to quantify any such changes longitudinally, through the early…

"Many Moons": Understanding Teacher Learning from a Teacher Education Perspective. Issue Paper 88-5.

ERIC Educational Resources Information Center

McDiarmid, G. Williamson; Ball, Deborah Loewenberg

The Teacher Education and Learning to Teach Study of the National Center for Research on Teacher Education combines case studies of teacher education programs with longitudinal studies of teacher learning. In this paper, the development of the theoretical framework on which instrumentation for the longitudinal study is based is discussed.…

Predictors of the Acquisition and Portability of Transferable Skills: A Longitudinal Portuguese Case Study on Education

ERIC Educational Resources Information Center

Rocha, Magda

2015-01-01

The basis for this longitudinal study was to find the predictors of transferable skills acquisition and portability among university sophomore students. The method employed was the path analysis using as variables: (1) the theoretical framework of transferable skills representations (Evers and Rush in "Manag Learn" 27(4):275-300, 1996;…

Longitudinal Associations Between Observed and Perceived Neighborhood Food Availability and Body Mass Index in a Multiethnic Urban Sample.

PubMed

Zenk, Shannon N; Mentz, Graciela; Schulz, Amy J; Johnson-Lawrence, Vicki; Gaines, Causandra R

2017-02-01

Blacks, Hispanics, and women of lower socioeconomic status tend to have a higher risk of obesity. Numerous studies over the past decade examined the role of the neighborhood food environment in body weight. However, few were longitudinal. This longitudinal study examined whether multiple measures of neighborhood food availability were associated with body mass index (BMI) in a predominately Black and Hispanic adult sample living in low- to moderate-income urban neighborhoods. This longitudinal study used two waves of data (2002, 2008), including interviewer-measured height and weight, from a community survey of adults ( n = 219). In both 2002 and 2008, multiple measures characterized neighborhood food availability: GIS-derived availability of retail food outlets (large grocery store, small grocery store, convenience store, liquor stores), observed fruit and vegetable availability (count of stores selling 10 or more fresh fruit or vegetable varieties), and perceived fruit and vegetable access. Random intercept models estimated multivariable associations, controlling for individual-level demographics and neighborhood median household income. Small grocery store availability was associated with 1.22-unit increase in BMI ( p = .047), while each unit increase in perceived fruit and vegetable access was associated with a 0.69-unit decrease in BMI ( p = .055). BMI was not associated with large grocery store, convenience store, or liquor store availability, or with observed fruit and vegetable availability. Findings suggest that improving the neighborhood food environment, particularly at small grocery stores, may help urban residents living in low- to moderate-income neighborhoods achieve healthier body weights over time.

Computer-based tools for assessing micro-longitudinal patterns of cognitive function in older adults.

PubMed

Brown, Laura J E; Adlam, Tim; Hwang, Faustina; Khadra, Hassan; Maclean, Linda M; Rudd, Bridey; Smith, Tom; Timon, Claire; Williams, Elizabeth A; Astell, Arlene J

2016-08-01

Patterns of cognitive change over micro-longitudinal timescales (i.e., ranging from hours to days) are associated with a wide range of age-related health and functional outcomes. However, practical issues of conducting high-frequency assessments make investigations of micro-longitudinal cognition costly and burdensome to run. One way of addressing this is to develop cognitive assessments that can be performed by older adults, in their own homes, without a researcher being present. Here, we address the question of whether reliable and valid cognitive data can be collected over micro-longitudinal timescales using unsupervised cognitive tests.In study 1, 48 older adults completed two touchscreen cognitive tests, on three occasions, in controlled conditions, alongside a battery of standard tests of cognitive functions. In study 2, 40 older adults completed the same two computerized tasks on multiple occasions, over three separate week-long periods, in their own homes, without a researcher present. Here, the tasks were incorporated into a wider touchscreen system (Novel Assessment of Nutrition and Ageing (NANA)) developed to assess multiple domains of health and behavior. Standard tests of cognitive function were also administered prior to participants using the NANA system.Performance on the two "NANA" cognitive tasks showed convergent validity with, and similar levels of reliability to, the standard cognitive battery in both studies. Completion and accuracy rates were also very high. These results show that reliable and valid cognitive data can be collected from older adults using unsupervised computerized tests, thus affording new opportunities for the investigation of cognitive.

Longitudinal associations of hypersomnolence and depression in the Wisconsin Sleep Cohort Study.

PubMed

Plante, David T; Finn, Laurel A; Hagen, Erika W; Mignot, Emmanuel; Peppard, Paul E

2017-01-01

Hypersomnolence is common in depression, however longitudinal associations of excessive daytime sleepiness (EDS), long habitual sleep duration, and objective sleep propensity with depressive symptomatology are not well established. Data from adults participating in the Wisconsin Sleep Cohort Study who had multiple assessments at 4-year intervals were utilized in analyses. Conditional (intrasubject) logistic regression estimated the likelihood of development of depression and three primary hypersomnolence measures: subjective EDS [Epworth Sleepiness Scale (ESS) >10], habitual sleep duration ≥9h/day, and increased physiological sleep propensity [multiple sleep latency test (MSLT) mean sleep latency <8min]. After adjusting for all covariates, the odds for development of depression were significantly increased 1.67-fold (95% CI 1.02-2.73, p=0.04) in participants who also developed subjective EDS. However, development of increased physiological sleep propensity on the MSLT was associated with a trend towards reduced odds for development of depression (odds ratio 0.50, 95% CI 0.24-1.06, p=0.07). No significant longitudinal association between excessive sleep duration and depression was observed. Depression was not verified by psychiatric interview and an objective measure of sleep duration was not utilized. Our results demonstrate a significant longitudinal association between increased subjective EDS and depression. However, increased physiological sleep propensity on the MSLT was paradoxically marginally protective against the development of depression. Further research is indicated to determine the mechanism underling divergent effects of various aspects of hypersomnolence on the course of mood disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

Replication of an association of variation in the FOXO3A gene with human longevity using both case–control and longitudinal data

PubMed Central

Soerensen, Mette; Dato, Serena; Christensen, Kaare; McGue, Matt; Stevnsner, Tinna; Bohr, Vilhelm A.; Christiansen, Lene

2010-01-01

Summary Genetic variation in FOXO3A has previously been associated with human longevity. Studies published so far have been case–control studies and hence vulnerable to bias introduced by cohort effects. In this study we extended the previous findings in the cohorts of oldest old Danes (the Danish 1905 cohort, N = 1089) and middle-aged Danes (N = 736), applying a longitudinal study design as well as the case–control study design. Fifteen SNPs were chosen in order to cover the known common variation in FOXO3A. Comparing SNP frequencies in the oldest old with middle-aged individuals, we found association (after correction for multiple testing) of eight SNPs; 4 (rs13217795, rs2764264, rs479744, and rs9400239) previously reported to be associated with longevity and four novel SNPs (rs12206094, rs13220810, rs7762395, and rs9486902 (corrected P-values 0.001–0.044). Moreover, we found association of the haplotypes TAC and CAC of rs9486902, rs10499051, and rs12206094 (corrected P-values: 0.01–0.03) with longevity. Finally, we here present data applying a longitudinal study design; when using follow-up survival data on the oldest old in a longitudinal analysis, we found no SNPs to remain significant after the correction for multiple testing (Bonferroni correction). Hence, our results support and extent the proposed role of FOXO3A as a candidate longevity gene for survival from younger ages to old age, yet not during old age. PMID:20849522

Testing cross-phenotype effects of rare variants in longitudinal studies of complex traits.

PubMed

Rudra, Pratyaydipta; Broadaway, K Alaine; Ware, Erin B; Jhun, Min A; Bielak, Lawrence F; Zhao, Wei; Smith, Jennifer A; Peyser, Patricia A; Kardia, Sharon L R; Epstein, Michael P; Ghosh, Debashis

2018-06-01

Many gene mapping studies of complex traits have identified genes or variants that influence multiple phenotypes. With the advent of next-generation sequencing technology, there has been substantial interest in identifying rare variants in genes that possess cross-phenotype effects. In the presence of such effects, modeling both the phenotypes and rare variants collectively using multivariate models can achieve higher statistical power compared to univariate methods that either model each phenotype separately or perform separate tests for each variant. Several studies collect phenotypic data over time and using such longitudinal data can further increase the power to detect genetic associations. Although rare-variant approaches exist for testing cross-phenotype effects at a single time point, there is no analogous method for performing such analyses using longitudinal outcomes. In order to fill this important gap, we propose an extension of Gene Association with Multiple Traits (GAMuT) test, a method for cross-phenotype analysis of rare variants using a framework based on the distance covariance. The approach allows for both binary and continuous phenotypes and can also adjust for covariates. Our simple adjustment to the GAMuT test allows it to handle longitudinal data and to gain power by exploiting temporal correlation. The approach is computationally efficient and applicable on a genome-wide scale due to the use of a closed-form test whose significance can be evaluated analytically. We use simulated data to demonstrate that our method has favorable power over competing approaches and also apply our approach to exome chip data from the Genetic Epidemiology Network of Arteriopathy. © 2018 WILEY PERIODICALS, INC.

Crohn's disease in Japan: diagnostic criteria and epidemiology.

PubMed

Yao, T; Matsui, T; Hiwatashi, N

2000-10-01

New diagnostic criteria for Crohn's disease and a review of Japanese epidemiologic studies are presented. New diagnostic criteria for Crohn's disease were established by the Research Committee of Inflammatory Bowel Disease, set up by the Japanese Ministry of Health and Welfare. For a definite diagnosis one of the following three conditions is required: 1) longitudinal ulcer or luminal deformity induced by longitudinal ulcer or cobblestone pattern, 2) intestinal small aphthous ulcerations arranged in a longitudinal fashion for at least three months plus noncaseating granulomas, and 3) multiple small aphthous ulcerations in both the upper and lower digestive tract not necessarily with longitudinal arrangement, for at least three months, plus noncaseating granulomas. Moreover, ulcerative colitis, ischemic enterocolitis, and acute infectious enterocolitis should be excluded. Data from the Japanese Ministry of Health and Welfare, in addition to data collected from two study groups, these being the two largest studies in Japan, are reviewed with regard to epidemiology. The number of patients with Crohn's disease has increased remarkably. The prevalence and the annual incidence of patients with Crohn's disease in Japan were estimated to be approximately 2.9 and 0.6 per 10(5) population in 1986, respectively, and 13.5 and 1.2 per 10(5) population in 1998. Characteristic features of Crohn's disease in Japan are that the male-female ratio exceeds 2, and that there is no second peak of incidence in the age group of 55 to 65 years. Clinically, Crohn's disease with only multiple small aphthous ulcerations, which is the earliest stage of the disease that is diagnosable, was found in 5 percent of patients.

Genome-Level Longitudinal Expression of Signaling Pathways and Gene Networks in Pediatric Septic Shock

PubMed Central

Shanley, Thomas P; Cvijanovich, Natalie; Lin, Richard; Allen, Geoffrey L; Thomas, Neal J; Doctor, Allan; Kalyanaraman, Meena; Tofil, Nancy M; Penfil, Scott; Monaco, Marie; Odoms, Kelli; Barnes, Michael; Sakthivel, Bhuvaneswari; Aronow, Bruce J; Wong, Hector R

2007-01-01

We have conducted longitudinal studies focused on the expression profiles of signaling pathways and gene networks in children with septic shock. Genome-level expression profiles were generated from whole blood-derived RNA of children with septic shock (n = 30) corresponding to day one and day three of septic shock, respectively. Based on sequential statistical and expression filters, day one and day three of septic shock were characterized by differential regulation of 2,142 and 2,504 gene probes, respectively, relative to controls (n = 15). Venn analysis demonstrated 239 unique genes in the day one dataset, 598 unique genes in the day three dataset, and 1,906 genes common to both datasets. Functional analyses demonstrated time-dependent, differential regulation of genes involved in multiple signaling pathways and gene networks primarily related to immunity and inflammation. Notably, multiple and distinct gene networks involving T cell- and MHC antigen-related biology were persistently downregulated on both day one and day three. Further analyses demonstrated large scale, persistent downregulation of genes corresponding to functional annotations related to zinc homeostasis. These data represent the largest reported cohort of patients with septic shock subjected to longitudinal genome-level expression profiling. The data further advance our genome-level understanding of pediatric septic shock and support novel hypotheses. PMID:17932561

Applying the institutional review board data repository approach to manage ethical considerations in evaluating and studying medical education

PubMed Central

Thayer, Erin K.; Rathkey, Daniel; Miller, Marissa Fuqua; Palmer, Ryan; Mejicano, George C.; Pusic, Martin; Kalet, Adina; Gillespie, Colleen; Carney, Patricia A.

2016-01-01

Issue Medical educators and educational researchers continue to improve their processes for managing medical student and program evaluation data using sound ethical principles. This is becoming even more important as curricular innovations are occurring across undergraduate and graduate medical education. Dissemination of findings from this work is critical, and peer-reviewed journals often require an institutional review board (IRB) determination. Approach IRB data repositories, originally designed for the longitudinal study of biological specimens, can be applied to medical education research. The benefits of such an approach include obtaining expedited review for multiple related studies within a single IRB application and allowing for more flexibility when conducting complex longitudinal studies involving large datasets from multiple data sources and/or institutions. In this paper, we inform educators and educational researchers on our analysis of the use of the IRB data repository approach to manage ethical considerations as part of best practices for amassing, pooling, and sharing data for educational research, evaluation, and improvement purposes. Implications Fostering multi-institutional studies while following sound ethical principles in the study of medical education is needed, and the IRB data repository approach has many benefits, especially for longitudinal assessment of complex multi-site data. PMID:27443407

Changes in aerobic power of men, ages 25-70 yr

NASA Technical Reports Server (NTRS)

Jackson, A. S.; Beard, E. F.; Wier, L. T.; Ross, R. M.; Stuteville, J. E.; Blair, S. N.

1995-01-01

This study quantified and compared the cross-sectional and longitudinal influence of age, self-report physical activity (SR-PA), and body composition (%fat) on the decline of maximal aerobic power (VO2peak). The cross-sectional sample consisted of 1,499 healthy men ages 25-70 yr. The 156 men of the longitudinal sample were from the same population and examined twice, the mean time between tests was 4.1 (+/- 1.2) yr. Peak oxygen uptake was determined by indirect calorimetry during a maximal treadmill exercise test. The zero-order correlations between VO2peak and %fat (r = -0.62) and SR-PA (r = 0.58) were significantly (P < 0.05) higher that the age correlation (r = -0.45). Linear regression defined the cross-sectional age-related decline in VO2peak at 0.46 ml.kg-1.min-1.yr-1. Multiple regression analysis (R = 0.79) showed that nearly 50% of this cross-sectional decline was due to %fat and SR-PA, adding these lifestyle variables to the multiple regression model reduced the age regression weight to -0.26 ml.kg-1.min-1.yr-1. Statistically controlling for time differences between tests, general linear models analysis showed that longitudinal changes in aerobic power were due to independent changes in %fat and SR-PA, confirming the cross-sectional results.

High frequency longitudinal profiling reveals hydrologic controls on solute sourcing, transport and processing in a karst river

NASA Astrophysics Data System (ADS)

Hensley, R. T.; Cohen, M. J.; Spangler, M.; Gooseff, M. N.

2017-12-01

The lower Santa Fe River is a large, karst river of north Florida, fed by numerous artesian springs and also containing multiple sink-rise systems. We performed repeated longitudinal profiles collecting very high frequency measurements of multiple stream parameters including temperature, dissolved oxygen, carbon dioxide, pH, dissolved organic matter, nitrate, ammonium, phosphate and turbidity. This high frequency dataset provided a spatially explicit understanding of solute sources and coupled biogeochemical processing rates along the 25 km study reach. We noted marked changes in river profiles as the river transitioned from low to high flow during the onset of the wet season. The role of lateral inflow from springs as the primary solute source was greatly reduced under high flow conditions. Effects of sink-rise systems, which under low flow conditions allow the majority of flow to bypass several kilometer long sections of the main channel, virtually disappeared under high flow conditions. Impeded light transmittance at high flow reduced primary production and by extension assimilatory nutrient uptake. This study demonstrates how high frequency longitudinal profiling can be used to observe how hydrologic conditions can alter groundwater-surface water interactions and modulate the sourcing, transport and biogeochemical processing of stream solutes.

Point and Click, Carefully: Investigating Inconsistent Response Styles in Middle School and College Students Involved in Web-Based Longitudinal Substance Use Research

PubMed Central

Wardell, Jeffrey D.; Rogers, Michelle L.; Simms, Leonard J.; Jackson, Kristina M.; Read, Jennifer P.

2014-01-01

This study investigated inconsistent responding to survey items by participants involved in longitudinal, web-based substance use research. We also examined cross-sectional and prospective predictors of inconsistent responding. Middle school (N = 1,023) and college students (N = 995) from multiple sites in the United States responded to online surveys assessing substance use and related variables in three waves of data collection. We applied a procedure for creating an index of inconsistent responding at each wave that involved identifying pairs of items with considerable redundancy and calculating discrepancies in responses to these items. Inconsistent responding was generally low in the Middle School sample and moderate in the College sample, with individuals showing only modest stability in inconsistent responding over time. Multiple regression analyses identified several baseline variables—including demographic, personality, and behavioral variables—that were uniquely associated with inconsistent responding both cross-sectionally and prospectively. Alcohol and substance involvement showed some bivariate associations with inconsistent responding, but these associations largely were accounted for by other factors. The results suggest that high levels of carelessness or inconsistency do not appear to characterize participants’ responses to longitudinal web-based surveys of substance use and support the use of inconsistency indices as a tool for identifying potentially problematic responders. PMID:24092819

Continuity of Genetic and Environmental Influences on Cognition across the Life Span: A Meta-Analysis of Longitudinal Twin and Adoption Studies

PubMed Central

Tucker-Drob, Elliot M.; Briley, Daniel A.

2014-01-01

The longitudinal rank-order stability of cognitive ability increases dramatically over the lifespan. Multiple theoretical perspectives have proposed that genetic and/or environmental mechanisms underlie the longitudinal stability of cognition, and developmental trends therein. However, the patterns of stability of genetic and environmental influences on cognition over the lifespan largely remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically-informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,538 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 non-adoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were low during early childhood, increased sharply over child development, and remained relatively high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and increased gradually to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment interaction and correlation. PMID:24611582

Longitudinal Changes in Serum Glucose Levels are Associated with Metabolic Changes in Alzheimer's Disease Related Brain Regions.

PubMed

Burns, Christine M; Kaszniak, Alfred W; Chen, Kewei; Lee, Wendy; Bandy, Daniel J; Caselli, Richard J; Reiman, Eric M

2018-01-01

The association between longitudinal changes in serum glucose level and longitudinal changes in [18F] Fluorodeoxyglucose-PET (FDG PET) measurements of Alzheimer's disease (AD) risk are unknown. To investigate whether variation in serum glucose levels across time are associated with changes in FDG PET measurements of cerebral metabolic rate for glucose (rCMRgl) in brain regions preferentially affected by Alzheimer's disease (AD). Participants are a subset of a prospective cohort study investigating FDG PET, apolipoprotein E (APOE) ɛ4, and risk for AD which includes data from baseline, interim, and follow up visits over 4.4±1.0-years. An automated brain-mapping algorithm was utilized to characterize and compare associations between longitudinal changes in serum glucose levels and longitudinal changes in rCMRgl. This study included 80 adults aged 61.5±5 years, including 38 carriers and 42 non-carriers of the APOE ɛ4 allele. Longitudinal increases in serum glucose levels were associated with longitudinal CMRgl decline in the vicinity of parietotemporal, precuneus/posterior cingulate, and prefrontal brain regions preferentially affected by AD (p < 0.05, corrected for multiple comparisons). Findings remained significant when controlled for APOE ɛ4 status and baseline and advancing age. Additional studies are needed to clarify and confirm the relationship between longitudinal changes in peripheral glucose and FDG PET measurements of AD risk. Future findings will set the stage on the use of FDG PET in the evaluation of possible interventions that target risk factors for the development of AD.

Constitutional growth delay pattern of growth in velo-cardio-facial syndrome: longitudinal follow up and final height of two cases.

PubMed

Turan, Serap; Ozdemir, Nihal; Güran, Tülay; Akalın, Figen; Akçay, Teoman; Ayabakan, Canan; Yılmaz, Yüksel; Bereket, Abdullah

2008-01-01

We report two patients with velo-cardio-facial syndrome (VCFS) who were admitted to our pediatric endocrinology clinic because of short stature and followed longitudinally until attainment of final height. Both patients followed a growth pattern consistent with constitutional delay of puberty with normal and near normal final height. Case 2 also had partial growth hormone (GH) deficiency and severe short stature (height SDS -3.4 SDS), but showed spontaneous catch-up and ended up with a final height of -2 SDS. These cases suggest that short stature in children with VCFS is due to a pattern of growth similar to that observed in constitutional delay of growth and puberty.

On the Use of Diversity Measures in Longitudinal Sequencing Studies of Microbial Communities.

PubMed

Wagner, Brandie D; Grunwald, Gary K; Zerbe, Gary O; Mikulich-Gilbertson, Susan K; Robertson, Charles E; Zemanick, Edith T; Harris, J Kirk

2018-01-01

Identification of the majority of organisms present in human-associated microbial communities is feasible with the advent of high throughput sequencing technology. As substantial variability in microbiota communities is seen across subjects, the use of longitudinal study designs is important to better understand variation of the microbiome within individual subjects. Complex study designs with longitudinal sample collection require analytic approaches to account for this additional source of variability. A common approach to assessing community changes is to evaluate the change in alpha diversity (the variety and abundance of organisms in a community) over time. However, there are several commonly used alpha diversity measures and the use of different measures can result in different estimates of magnitude of change and different inferences. It has recently been proposed that diversity profile curves are useful for clarifying these differences, and may provide a more complete picture of the community structure. However, it is unclear how to utilize these curves when interest is in evaluating changes in community structure over time. We propose the use of a bi-exponential function in a longitudinal model that accounts for repeated measures on each subject to compare diversity profiles over time. Furthermore, it is possible that no change in alpha diversity (single community/sample) may be observed despite the presence of a highly divergent community composition. Thus, it is also important to use a beta diversity measure (similarity between multiple communities/samples) that captures changes in community composition. Ecological methods developed to evaluate temporal turnover have currently only been applied to investigate changes of a single community over time. We illustrate the extension of this approach to multiple communities of interest (i.e., subjects) by modeling the beta diversity measure over time. With this approach, a rate of change in community composition is estimated. There is a need for the extension and development of analytic methods for longitudinal microbiota studies. In this paper, we discuss different approaches to model alpha and beta diversity indices in longitudinal microbiota studies and provide both a review of current approaches and a proposal for new methods.

On the Use of Diversity Measures in Longitudinal Sequencing Studies of Microbial Communities

PubMed Central

Wagner, Brandie D.; Grunwald, Gary K.; Zerbe, Gary O.; Mikulich-Gilbertson, Susan K.; Robertson, Charles E.; Zemanick, Edith T.; Harris, J. Kirk

2018-01-01

Identification of the majority of organisms present in human-associated microbial communities is feasible with the advent of high throughput sequencing technology. As substantial variability in microbiota communities is seen across subjects, the use of longitudinal study designs is important to better understand variation of the microbiome within individual subjects. Complex study designs with longitudinal sample collection require analytic approaches to account for this additional source of variability. A common approach to assessing community changes is to evaluate the change in alpha diversity (the variety and abundance of organisms in a community) over time. However, there are several commonly used alpha diversity measures and the use of different measures can result in different estimates of magnitude of change and different inferences. It has recently been proposed that diversity profile curves are useful for clarifying these differences, and may provide a more complete picture of the community structure. However, it is unclear how to utilize these curves when interest is in evaluating changes in community structure over time. We propose the use of a bi-exponential function in a longitudinal model that accounts for repeated measures on each subject to compare diversity profiles over time. Furthermore, it is possible that no change in alpha diversity (single community/sample) may be observed despite the presence of a highly divergent community composition. Thus, it is also important to use a beta diversity measure (similarity between multiple communities/samples) that captures changes in community composition. Ecological methods developed to evaluate temporal turnover have currently only been applied to investigate changes of a single community over time. We illustrate the extension of this approach to multiple communities of interest (i.e., subjects) by modeling the beta diversity measure over time. With this approach, a rate of change in community composition is estimated. There is a need for the extension and development of analytic methods for longitudinal microbiota studies. In this paper, we discuss different approaches to model alpha and beta diversity indices in longitudinal microbiota studies and provide both a review of current approaches and a proposal for new methods. PMID:29872428

Nonparaxial propagation and focusing properties of azimuthal-variant vector fields diffracted by an annular aperture.

PubMed

Gu, Bing; Xu, Danfeng; Pan, Yang; Cui, Yiping

2014-07-01

Based on the vectorial Rayleigh-Sommerfeld integrals, the analytical expressions for azimuthal-variant vector fields diffracted by an annular aperture are presented. This helps us to investigate the propagation behaviors and the focusing properties of apertured azimuthal-variant vector fields under nonparaxial and paraxial approximations. The diffraction by a circular aperture, a circular disk, or propagation in free space can be treated as special cases of this general result. Simulation results show that the transverse intensity, longitudinal intensity, and far-field divergence angle of nonparaxially apertured azimuthal-variant vector fields depend strongly on the azimuthal index, the outer truncation parameter and the inner truncation parameter of the annular aperture, as well as the ratio of the waist width to the wavelength. Moreover, the multiple-ring-structured intensity pattern of the focused azimuthal-variant vector field, which originates from the diffraction effect caused by an annular aperture, is experimentally demonstrated.

POWER ANALYSIS FOR COMPLEX MEDIATIONAL DESIGNS USING MONTE CARLO METHODS

PubMed Central

Thoemmes, Felix; MacKinnon, David P.; Reiser, Mark R.

2013-01-01

Applied researchers often include mediation effects in applications of advanced methods such as latent variable models and linear growth curve models. Guidance on how to estimate statistical power to detect mediation for these models has not yet been addressed in the literature. We describe a general framework for power analyses for complex mediational models. The approach is based on the well known technique of generating a large number of samples in a Monte Carlo study, and estimating power as the percentage of cases in which an estimate of interest is significantly different from zero. Examples of power calculation for commonly used mediational models are provided. Power analyses for the single mediator, multiple mediators, three-path mediation, mediation with latent variables, moderated mediation, and mediation in longitudinal designs are described. Annotated sample syntax for Mplus is appended and tabled values of required sample sizes are shown for some models. PMID:23935262

Comparison of qualitative and quantitative CT and MRI parameters for monitoring of longitudinal spine involvement in patients with multiple myeloma.

PubMed

Horger, M; Fritz, J; Thaiss, W M; Ditt, H; Weisel, K; Haap, M; Kloth, Christopher

2018-03-01

To compare qualitative and quantitative computed tomography (CT) and magnetic resonance imaging (MRI) parameters for longitudinal disease monitoring of multiple myeloma (MM) of the axial skeleton. We included 31 consecutive patients (17 m; mean age 59.20 ± 8.08 years) with MM, who underwent all baseline (n = 31) and at least one or more (n = 47) follow-up examinations consisting of multi-parametric non-enhanced whole-body MRI ( WB MRI) and non-enhanced whole-body reduced-dose thin-section MDCT (NEWBMDCT) between 06/2013 and 09/2016. We classified response according to qualitative CT criteria into progression (PD), stable(SD), partial/very good partial (PR/VGPR) and complete response(CR), grouping the latter three together for statistical analysis because CT cannot reliably assess PR and CR. Qualitative MR-response criteria were defined and grouped similarly to CT using longitudinal quantification of signal-intensity changes on T1w/STIR/ T2*w and calculating ADC-values. Standard of reference was the hematological laboratory (M-gradient). Hematological response categories were CR (14/47, 29.7%), PR (2/47, 4.2%), SD (16/47, 34.0%) and PD (15/47, 29.9%). Qualitative-CT-evaluation showed PD in 12/47 (25.5%) and SD/PR/VGPR/CR in 35/47 (74.5%) cases. These results were confirmed by quantitative-CT in all focal lytic lesions (p < 0.001). Quantitative-CT at sites with diffuse bone involvement showed significant increase of maximum bone attenuation (p < 0.001*) and significant decrease of minimal bone (p < 0.002*) in the SD/PR/VGPR/CR group. Qualitative MRI showed PD in 14/47 (29.7%) and SD/PR/VGPR/CR in 33/47 (70.3%). Quantitative MRI diagnosis showed a statistically significant decrease in signal intensity on short tau inversion recovery sequences (STIR) in bone marrow in patients with diffuse bone marrow involvement achieving SD/PR/VGPR/CR (p < 0.001*). Imaging response monitoring using MRI is superior to CT only if qualitative parameters are used, whereas there was no definite benefit from using quantitative parameters with either CT or MRI.

Parental decision-making on utilisation of out-of-home respite in children's palliative care: findings of qualitative case study research - a proposed new model.

PubMed

Ling, J; Payne, S; Connaire, K; McCarron, M

2016-01-01

Respite in children's palliative care aims to provide a break for family's from the routine of caring. Parental decision-making regarding the utilisation of out-of-home respite is dependent on many interlinking factors including the child's age, diagnosis, geographical location and the family's capacity to meet their child's care needs. A proposed model for out-of-home respite has been developed based on the findings of qualitative case study research. Utilising multiple, longitudinal, qualitative case study design, the respite needs and experiences of parents caring for a child with a life-limiting condition were explored. Multiple, in-depth interviews were undertaken with the parents identified by a hospital-based children's palliative care team. Data were analysed using thematic analysis. Each individual case consists of a whole study. Cross-case comparison was also conducted. Nine families were recruited and followed for two years. A total of 19 in-depth interviews were conducted with mothers and fathers (one or both) caring for a child with a life-limiting condition in Ireland. Each family reported vastly different needs and experiences of respite from their own unique perspective. Cross-case comparison showed that for all parents utilising respite care, regardless of their child's age and condition, home was the location of choice. Many interlinking factors influencing these decisions included: past experience of in-patient care, and trust and confidence in care providers. Issues were raised regarding the impact of care provision in the home on family life, siblings and the concept of home. Respite is an essential element of children's palliative care. Utilisation of out-of-home respite is heavily dependent on a number of interlinked and intertwined factors. The proposed model of care offers an opportunity to identify how these decisions are made and may ultimately assist in identifying the elements of responsive and family-focused respite that are important to families of children with life-limiting conditions. © 2015 John Wiley & Sons Ltd.

Retention of Gadolinium-Based Contrast Agents in Multiple Sclerosis: Retrospective Analysis of an 18-Year Longitudinal Study.

PubMed

Forslin, Y; Shams, S; Hashim, F; Aspelin, P; Bergendal, G; Martola, J; Fredrikson, S; Kristoffersen-Wiberg, M; Granberg, T

2017-07-01

Gadolinium-based contrast agents have been associated with lasting high T1-weighted signal intensity in the dentate nucleus and globus pallidus, with histopathologically confirmed gadolinium retention. We aimed to longitudinally investigate the relationship of multiple gadolinium-based contrast agent administrations to the Signal Intensity Index in the dentate nucleus and globus pallidus and any associations with cognitive function in multiple sclerosis. The Signal Intensity Index in the dentate nucleus and globus pallidus was retrospectively evaluated on T1-weighted MR imaging in an 18-year longitudinal cohort study of 23 patients with MS receiving multiple gadolinium-based contrast agent administrations and 23 healthy age- and sex-matched controls. Participants also underwent comprehensive neuropsychological testing. Patients with MS had a higher Signal Intensity Index in the dentate nucleus ( P < .001), but not in the globus pallidus ( P = .19), compared with non-gadolinium-based contrast agent-exposed healthy controls by an unpaired t test. Increasing numbers of gadolinium-based contrast agent administrations were associated with an increased Signal Intensity Index in the dentate nucleus (β = 0.45, P < .001) and globus pallidus (β = 0.60, P < .001). This association remained stable with corrections for the age, disease duration, and physical disability for both the dentate nucleus (β = 0.43, P = .001) and globus pallidus (β = 0.58, P < .001). An increased Signal Intensity Index in the dentate nucleus among patients with MS was associated with lower verbal fluency scores, which remained significant after correction for several aspects of disease severity (β = -0.40 P = .013). Our data corroborate previous reports of lasting gadolinium retention in brain tissues. An increased Signal Intensity Index in the dentate nucleus and globus pallidus was associated with lower verbal fluency, which does not prove causality but encourages further studies on cognition and gadolinium-based contrast agent administration. © 2017 by American Journal of Neuroradiology.

Longitudinal Measurement Equivalence of Subjective Language Brokering Experiences Scale in Mexican American Adolescents

PubMed Central

Kim, Su Yeong; Hou, Yang; Shen, Yishan; Zhang, Minyu

2016-01-01

Objectives Language brokering occurs frequently in immigrant families and can have significant implications for the well-being of family members involved. The present study aimed to develop and validate a measure that can be used to assess multiple dimensions of subjective language brokering experiences among Mexican American adolescents. Methods Participants were 557 adolescent language brokers (54.2% female, Mage.wave1 =12.96, SD=.94) in Mexican American families. Results Using exploratory and confirmatory factor analyses, we were able to identify seven reliable subscales of language brokering: linguistic benefits, socio-emotional benefits, efficacy, positive parent-child relationships, parental dependence, negative feelings, and centrality. Tests of factorial invariance show that these subscales demonstrate, at minimum, partial strict invariance across time and across experiences of translating for mothers and fathers, and in most cases, also across adolescent gender, nativity, and translation frequency. Thus, in general, the means of the subscales and the relations among the subscales with other variables can be compared across these different occasions and groups. Tests of criterion-related validity demonstrated that these subscales correlated, concurrently and longitudinally, with parental warmth and hostility, parent-child alienation, adolescent family obligation, depressive symptoms, resilience, and life meaning. Conclusions This reliable and valid subjective language brokering experiences scale will be helpful for gaining a better understanding of adolescents’ language brokering experiences with their mothers and fathers, and how such experiences may influence their development. PMID:27362872

"Miss, How do you Write Hipotesis?" Learning to Teach Science to English Language Learners While Navigating Affordances and Constraints: A Longitudinal Multiple Case Study

NASA Astrophysics Data System (ADS)

Ortega, Irasema

Early career science teachers are often assigned to classrooms with high numbers of English language learners (ELL students). As these teachers learn to become effective practitioners, the circumstances surrounding them merit a thorough examination. This study examines the longitudinal changes in Pedagogical Content Knowledge (PCK) and practices of six early career science teachers who taught in urban schools. The teachers participated in the Alternative Support for Induction Science Teachers (ASIST) program during their initial two years of teaching. Our research team followed the participants over a five-year period. This study focuses on data from Years 1, 3, and 5. The data collected included classroom observations and interviews. In addition, classroom artifacts were collected periodically for the purpose of triangulation. The analysis of the data revealed that with the support of the ASIST program, the teachers implemented inquiry lessons and utilized instructional materials that promoted academic language skills and science competencies among their ELL students. Conversely, standardized testing, teaching assignment, and school culture played a role in constraining the implementation of inquiry-based practices. The results of this study call for collaborative efforts among university science educators and school administrators to provide professional development opportunities and support for the implementation of inquiry and language practices among early career science teachers of ELL students.

Longitudinal Average Attributable Fraction as a Method for Studying Time-Varying Conditions and Treatments on Recurrent Self-rated Health: The Case of Medications in Older Adults with Multiple Chronic Conditions

PubMed Central

Allore, Heather G.; Zhan, Yilei; Tinetti, Mary; Trentalange, Mark; McAvay, Gail

2015-01-01

Purpose The objective is to modify the longitudinal extension of the average attributable fraction (LE-AAF) for recurrent outcomes with time-varying exposures and control for covariates. Methods We included Medicare Current Beneficiary Survey participants with two or more chronic conditions enrolled from 2005-2009 with follow-up through 2011. Nine time-varying medications indicated for nine time-varying common chronic conditions and 14 out of 18 forward-selected participant characteristics were used as control variables in the generalized estimating equations step of the LE-AAF to estimate associations with the recurrent universal health outcome self-rated health (SRH). Modifications of the LE-AAF were made to accommodate these indicated medication-condition interactions and covariates. Variability was empirically estimated by bias-corrected and accelerated bootstrapping. Results In the adjusted LE-AAF, thiazide, warfarin and clopidogrel had significant contributions of 1.2%, 0.4%, 0.2% respectively to low (poor or fair) SRH; while there were no significant contributions of the other medications to SRH. Hyperlipidemia significantly contributed 4.6% to high SRH. All the other conditions except atrial fibrillation contributed significantly to low SRH. Conclusions Our modifications to the LE-AAF method apply to a recurrent binary outcome with time-varying factors accounting for covariates. PMID:26033374

Insights from the Global Longitudinal Study of Osteoporosis in Women (GLOW).

PubMed

Watts, Nelson B

2014-07-01

GLOW is an observational, longitudinal, practice-based cohort study of osteoporosis in 60,393 women aged ≥55 years in 10 countries on three continents. In this Review, we present insights from the first 3 years of the study. Despite cost analyses being frequently based on spine and hip fractures, we found that nonvertebral, nonhip fractures were around five times more common and doubled the use of health-care resources compared with hip and spine fractures combined. Fractures not at the four so-called major sites in FRAX(®) (upper arm, forearm, hip and clinical vertebral fractures) account for >40% of all fractures. The risk of fracture is increased by various comorbidities, such as Parkinson disease, multiple sclerosis and lung and heart disease. Obesity, although thought to be protective against all fractures, substantially increased the risk of fractures in the ankle or lower leg. Simple assessment by age plus fracture history has good predictive value for all fractures, but risk profiles differ for first and subsequent fractures. Fractures diminish quality of life as much or more than diabetes mellitus, arthritis and lung disease, yet women substantially underestimate their own fracture risk. Treatment rates in patients at high risk of fracture are below those recommended but might be too frequent in women at low risk. Comorbidities and the limits of current therapeutic regimens jeopardize the efficacy of drugs; new regimens should be explored for severe cases.

Estimation of True Change with Three-Wave Data.

ERIC Educational Resources Information Center

Gupta, J. K.; And Others

1988-01-01

A multiple regression model for estimating true change of an individual by using information in addition to pretest-posttest data is described. Longitudinal panel or multi-wave data taken between the pretest and the posttest constitute the additional information. (TJH)

Penalized maximum likelihood simultaneous longitudinal PET image reconstruction with difference-image priors.

PubMed

Ellis, Sam; Reader, Andrew J

2018-04-26

Many clinical contexts require the acquisition of multiple positron emission tomography (PET) scans of a single subject, for example, to observe and quantitate changes in functional behaviour in tumors after treatment in oncology. Typically, the datasets from each of these scans are reconstructed individually, without exploiting the similarities between them. We have recently shown that sharing information between longitudinal PET datasets by penalizing voxel-wise differences during image reconstruction can improve reconstructed images by reducing background noise and increasing the contrast-to-noise ratio of high-activity lesions. Here, we present two additional novel longitudinal difference-image priors and evaluate their performance using two-dimesional (2D) simulation studies and a three-dimensional (3D) real dataset case study. We have previously proposed a simultaneous difference-image-based penalized maximum likelihood (PML) longitudinal image reconstruction method that encourages sparse difference images (DS-PML), and in this work we propose two further novel prior terms. The priors are designed to encourage longitudinal images with corresponding differences which have (a) low entropy (DE-PML), and (b) high sparsity in their spatial gradients (DTV-PML). These two new priors and the originally proposed longitudinal prior were applied to 2D-simulated treatment response [ 18 F]fluorodeoxyglucose (FDG) brain tumor datasets and compared to standard maximum likelihood expectation-maximization (MLEM) reconstructions. These 2D simulation studies explored the effects of penalty strengths, tumor behaviour, and interscan coupling on reconstructed images. Finally, a real two-scan longitudinal data series acquired from a head and neck cancer patient was reconstructed with the proposed methods and the results compared to standard reconstruction methods. Using any of the three priors with an appropriate penalty strength produced images with noise levels equivalent to those seen when using standard reconstructions with increased counts levels. In tumor regions, each method produces subtly different results in terms of preservation of tumor quantitation and reconstruction root mean-squared error (RMSE). In particular, in the two-scan simulations, the DE-PML method produced tumor means in close agreement with MLEM reconstructions, while the DTV-PML method produced the lowest errors due to noise reduction within the tumor. Across a range of tumor responses and different numbers of scans, similar results were observed, with DTV-PML producing the lowest errors of the three priors and DE-PML producing the lowest bias. Similar improvements were observed in the reconstructions of the real longitudinal datasets, although imperfect alignment of the two PET images resulted in additional changes in the difference image that affected the performance of the proposed methods. Reconstruction of longitudinal datasets by penalizing difference images between pairs of scans from a data series allows for noise reduction in all reconstructed images. An appropriate choice of penalty term and penalty strength allows for this noise reduction to be achieved while maintaining reconstruction performance in regions of change, either in terms of quantitation of mean intensity via DE-PML, or in terms of tumor RMSE via DTV-PML. Overall, improving the image quality of longitudinal datasets via simultaneous reconstruction has the potential to improve upon currently used methods, allow dose reduction, or reduce scan time while maintaining image quality at current levels. © 2018 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

A novel statistical approach shows evidence for multi-system physiological dysregulation during aging.

PubMed

Cohen, Alan A; Milot, Emmanuel; Yong, Jian; Seplaki, Christopher L; Fülöp, Tamàs; Bandeen-Roche, Karen; Fried, Linda P

2013-03-01

Previous studies have identified many biomarkers that are associated with aging and related outcomes, but the relevance of these markers for underlying processes and their relationship to hypothesized systemic dysregulation is not clear. We address this gap by presenting a novel method for measuring dysregulation via the joint distribution of multiple biomarkers and assessing associations of dysregulation with age and mortality. Using longitudinal data from the Women's Health and Aging Study, we selected a 14-marker subset from 63 blood measures: those that diverged from the baseline population mean with age. For the 14 markers and all combinatorial sub-subsets we calculated a multivariate distance called the Mahalanobis distance (MHBD) for all observations, indicating how "strange" each individual's biomarker profile was relative to the baseline population mean. In most models, MHBD correlated positively with age, MHBD increased within individuals over time, and higher MHBD predicted higher risk of subsequent mortality. Predictive power increased as more variables were incorporated into the calculation of MHBD. Biomarkers from multiple systems were implicated. These results support hypotheses of simultaneous dysregulation in multiple systems and confirm the need for longitudinal, multivariate approaches to understanding biomarkers in aging. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The COMPASS study: a longitudinal hierarchical research platform for evaluating natural experiments related to changes in school-level programs, policies and built environment resources.

PubMed

Leatherdale, Scott T; Brown, K Stephen; Carson, Valerie; Childs, Ruth A; Dubin, Joel A; Elliott, Susan J; Faulkner, Guy; Hammond, David; Manske, Steve; Sabiston, Catherine M; Laxer, Rachel E; Bredin, Chad; Thompson-Haile, Audra

2014-04-08

Few researchers have the data required to adequately understand how the school environment impacts youth health behaviour development over time. COMPASS is a prospective cohort study designed to annually collect hierarchical longitudinal data from a sample of 90 secondary schools and the 50,000+ grade 9 to 12 students attending those schools. COMPASS uses a rigorous quasi-experimental design to evaluate how changes in school programs, policies, and/or built environment (BE) characteristics are related to changes in multiple youth health behaviours and outcomes over time. These data will allow for the quasi-experimental evaluation of natural experiments that will occur within schools over the course of COMPASS, providing a means for generating "practice based evidence" in school-based prevention programming. COMPASS is the first study with the infrastructure to robustly evaluate the impact that changes in multiple school-level programs, policies, and BE characteristics within or surrounding a school might have on multiple youth health behaviours or outcomes over time. COMPASS will provide valuable new insight for planning, tailoring and targeting of school-based prevention initiatives where they are most likely to have impact.

[Information management in multicenter studies: the Brazilian longitudinal study for adult health].

PubMed

Duncan, Bruce Bartholow; Vigo, Álvaro; Hernandez, Émerson; Luft, Vivian Cristine; Ahlert, Hubert; Bergmann, Kaiser; Mota, Eduardo

2013-06-01

Information management in large multicenter studies requires a specialized approach. The Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil - Brazilian Longitudinal Study for Adult Health) has created a Datacenter to enter and manage its data system. The aim of this paper is to describe the steps involved, including the information entry, transmission and management methods. A web system was developed in order to allow, in a safe and confidential way, online data entry, checking and editing, as well as the incorporation of data collected on paper. Additionally, a Picture Archiving and Communication System was implemented and customized for echocardiography and retinography. It stores the images received from the Investigation Centers and makes them available at the Reading Centers. Finally, data extraction and cleaning processes were developed to create databases in formats that enable analyses in multiple statistical packages.

Joint Models of Longitudinal and Time-to-Event Data with More Than One Event Time Outcome: A Review.

PubMed

Hickey, Graeme L; Philipson, Pete; Jorgensen, Andrea; Kolamunnage-Dona, Ruwanthi

2018-01-31

Methodological development and clinical application of joint models of longitudinal and time-to-event outcomes have grown substantially over the past two decades. However, much of this research has concentrated on a single longitudinal outcome and a single event time outcome. In clinical and public health research, patients who are followed up over time may often experience multiple, recurrent, or a succession of clinical events. Models that utilise such multivariate event time outcomes are quite valuable in clinical decision-making. We comprehensively review the literature for implementation of joint models involving more than a single event time per subject. We consider the distributional and modelling assumptions, including the association structure, estimation approaches, software implementations, and clinical applications. Research into this area is proving highly promising, but to-date remains in its infancy.

A Manual for the Illinois Student Longitudinal Case Study System (ISLCS). Procedures and Materials for Planning and Implementing the ISLCS.

ERIC Educational Resources Information Center

Carvell, Fred; Carvell, Joan B.

Designed for local school and district vocational educators, this manual contains instructions and materials necessary to plan and implement a student longitudinal followup system. Part 1 provides background information and definitions used in the system. In part 2 are described the 11 major activities that must be undertaken by local program…

Effects of Early and Later Family Violence on Children's Behavior Problems and Depression: A Longitudinal, Multi-Informant Perspective

ERIC Educational Resources Information Center

Sternberg, Kathleen J.; Lamb, Michael E.; Guterman, Eva; Abbott, Craig B.

2006-01-01

Objectives: To examine the effects of different forms of family violence at two developmental stages by assessing a sample of 110 Israeli children, drawn from the case files of Israeli family service agencies, studied longitudinally in both middle childhood and adolescence. Methods: Information about the children's adjustment was obtained from…

A Longitudinal Study of Environmental and Outdoor Education: A Cultural Change

ERIC Educational Resources Information Center

Tal, Tali; Morag, Orly

2013-01-01

In this case-study, we present a longitudinal study of one elementary (grades 1-6) school's environmental education (EE) in order to understand the ways in which the school culture supports outdoor EE as a critical component of their science education program. The school, which was known for its school-based EE curriculum that encompasses an…

Becoming (Less) Scientific: A Longitudinal Study of Students' Identity Work from Elementary to Middle School Science

ERIC Educational Resources Information Center

Carlone, Heidi B.; Scott, Catherine M.; Lowder, Cassi

2014-01-01

Students' declining science interest in middle school is often attributed to psychological factors like shifts of motivational values, decrease in self-efficacy, or doubts about the utility of schooling in general. This paper adds to accounts of the middle school science problem through an ethnographic, longitudinal case study of three…

A Longitudinal Study of Post-School Provision for Irish School-Leavers with Intellectual Disability

ERIC Educational Resources Information Center

McConkey, Roy; Kelly, Fionnola; Craig, Sarah; Keogh, Fiona

2017-01-01

Background: In recent years, efforts have been made to improve the transition of pupils with intellectual disabilities to adult services and to offer a wider range of choices. However, there have been few longitudinal studies to monitor the services provided to young adults post-school. This case study in the Republic of Ireland identified the…

Developmental Trajectories in Adolescents and Adults With Autism: The Case of Daily Living Skills

ERIC Educational Resources Information Center

Smith, Leann E.; Maenner, Matthew J.; Seltzer, Marsha Mailick

2012-01-01

Objective: This study aimed to investigate the longitudinal course of daily living skills in a large, community-based sample of adolescents and adults with autism spectrum disorders (ASD) over a 10-year period. Method: Adolescents and adults with ASD (n = 397) were drawn from an ongoing, longitudinal study of individuals with ASD and their…

Students' Understanding of the Nature of Matter and Chemical Reactions--A Longitudinal Study of Conceptual Restructuring

ERIC Educational Resources Information Center

Øyehaug, Anne Bergliot; Holt, Anne

2013-01-01

This longitudinal study aims to provide greater insight into how students' understanding of matter and chemical reactions develops over time and how their knowledge structures are restructured. Four case-study students in a Norwegian primary school were followed for two years from age 10-11 to age 12-13. Researchers were responsible for…

Traumatic longitudinal splitting of the inferior rectus muscle

PubMed Central

Laursen, Jessica; Demer, Joseph L.

2011-01-01

Orbital floor fractures and associated injuries can cause strabismus. We present the case of a 34-year-old man with incomitant strabismus following orbital reconstruction after a high-impact baseball injury. Multipositional, high-resolution magnetic resonance imaging (MRI) revealed extensive longitudinal splitting of the inferior rectus muscle by an orbital floor implant that separated its orbital and global layers. PMID:21463958

A long term study of pulmonary function among US refractory ceramic fibre workers

PubMed Central

LeMasters, Grace K; Hilbert, Timothy J; Levin, Linda S; Rice, Carol H; Borton, Eric K; Lockey, James E

2010-01-01

Background Cross-sectional studies have shown declines in lung function among refractory ceramic fibre (RCF) workers with increasing fibre exposure. This study followed current and former workers (n=1396) for up to 17 years and collected 5243 pulmonary function tests. Methods Cumulative fibre exposure and production years were categorised into exposure levels at five manufacturing locations. Conventional longitudinal models did not adequately partition age-related changes from other time-dependent variables. Therefore, a restricted cubic spline model was developed to account for the non-linear decline with age. Results Cumulative fibre >60 fibre-months/cc showed a significant loss in lung function at the first test. When results were examined longitudinally, cumulative exposure was confounded with age as workers with the highest cumulative exposure were generally older. A longitudinal model adjusted by age groups was implemented to control for this confounding. No consistent longitudinal loss in lung function was observed with RCF exposure. Smoking, initial weight and weight increase were significant factors. Conclusion No consistent decline was observed longitudinally with exposure to RCF, although cross-sectional and longitudinal findings were discordant. Confounding and accelerated lung function declines with ageing and the correlation of multiple time-dependent variables should be considered in order to minimise error and maximise precision. An innovative statistical methodology for these types of data is described. PMID:20798015

Data Use and Inquiry in Research-Practice Partnerships: Four Case Examples

ERIC Educational Resources Information Center

Biag, Manuelito; Gerstein, Amy; Fehrer, Kendra; Sanchez, Monika; Sipes, Laurel

2016-01-01

The four case examples presented in this brief are drawn from the Gardner Center's substantial experience conducting rigorous research in research-practice partnerships. The first case describes a partnership approach that enhances a school district's capacity to use integrated longitudinal data to tackle persistent problems of practice and…

Methodological issues underlying multiple decrement life table analysis.

PubMed

Mode, C J; Avery, R C; Littman, G S; Potter, R G

1977-02-01

In this paper, the actuarial method of multiple decrement life table analysis of censored, longitudinal data is examined. The discussion is organized in terms of the first segment of usage of an intrauterine device. Weaknesses of the actuarial approach are pointed out, and an alternative approach, based on the classical model of competing risks, is proposed. Finally, the actuarial and the alternative method of analyzing censored data are compared, using data from the Taichung Medical Study on Intrauterine Devices.

Exploring the Temperature Dependent Solid-State ALC Spectrum of the C6H6Mu• Radical with Ab-Initio Simulation Techniques

NASA Astrophysics Data System (ADS)

Sturniolo, S.; Liborio, L.; Pratt, F. L.; Cottrell, S. P.; Jochym, D. B.; Montanari, B.

The longitudinal field Avoided Level Crossing (ALC) muon spectrum of crystalline benzene is found to exhibit multiple complex features that strongly depend on temperature. In this work, a number of different computational techniques were used in conjunction to explain this behavior. An overall picture emerges in which the spectrum appears to be the result of an interplay of multiple dynamical effects, both classical and quantum mechanical.

Exposure enriched outcome dependent designs for longitudinal studies of gene-environment interaction.

PubMed

Sun, Zhichao; Mukherjee, Bhramar; Estes, Jason P; Vokonas, Pantel S; Park, Sung Kyun

2017-08-15

Joint effects of genetic and environmental factors have been increasingly recognized in the development of many complex human diseases. Despite the popularity of case-control and case-only designs, longitudinal cohort studies that can capture time-varying outcome and exposure information have long been recommended for gene-environment (G × E) interactions. To date, literature on sampling designs for longitudinal studies of G × E interaction is quite limited. We therefore consider designs that can prioritize a subsample of the existing cohort for retrospective genotyping on the basis of currently available outcome, exposure, and covariate data. In this work, we propose stratified sampling based on summaries of individual exposures and outcome trajectories and develop a full conditional likelihood approach for estimation that adjusts for the biased sample. We compare the performance of our proposed design and analysis with combinations of different sampling designs and estimation approaches via simulation. We observe that the full conditional likelihood provides improved estimates for the G × E interaction and joint exposure effects over uncorrected complete-case analysis, and the exposure enriched outcome trajectory dependent design outperforms other designs in terms of estimation efficiency and power for detection of the G × E interaction. We also illustrate our design and analysis using data from the Normative Aging Study, an ongoing longitudinal cohort study initiated by the Veterans Administration in 1963. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Conscience in Childhood: Old Questions, New Answers

ERIC Educational Resources Information Center

Aksan, Nazan; Kochanska, Grazyna

2005-01-01

Although conscience has been the focus of reflection for centuries, fundamental questions regarding its organization have not been fully answered. To address those questions, the authors applied structural equation modeling techniques to longitudinal data comprising multiple behavioral measures of children's conscience, obtained in parallel…

DIZZINESS AND HEAD INJURY.

PubMed

BARBER, H O

1965-05-01

Dizziness, whether vague or specifically rotational, is a common sequel to head injury, and is often postural. One hundred and sixty-five patients with this symptom were examined. The simple posture tests employed to detect positional nystagmus are described. This physical finding was present in one-quarter of the entire group, and in nearly one-half of cases of longitudinal fracture of temporal bone. In such cases, it is an objective finding that corresponds precisely to the patient's complaint of vertigo.Transverse fracture of temporal bone destroys the inner ear in both cochlear and vestibular parts. Longitudinal fracture is commoner and causes bleeding from the ear; inner-ear damage is usually minor.In the rare cases where persisting postural vertigo and positional nystagmus are disabling, relief of the symptom may be achieved by vestibular denervation of the affected side.

Constitutional Growth Delay Pattern of Growth in Velo−Cardio−Facial Syndrome: Longitudinal follow up and final height of two cases

PubMed Central

Özdemir, Nihal; Güran, Tülay; Akalın, Figen; Akçay, Teoman; Ayabakan, Canan; Yılmaz, Yüksel; Bereket, Abdullah

2008-01-01

We report two patients with velo−cardio−facial syndrome (VCFS) who were admitted to our pediatric endocrinology clinic because of short stature and followed longitudinally until attainment of final height. Both patients followed a growth pattern consistent with constitutional delay of puberty with normal and near normal final height. Case 2 also had partial growth hormone (GH) deficiency and severe short stature (height SDS −3.4 SDS), but showed spontaneous catch−up and ended up with a final height of −2 SDS. These cases suggest that short stature in children with VCFS is due to a pattern of growth similar to that observed in constitutional delay of growth and puberty. Conflict of interest:None declared. PMID:21318064

Longitudinal control effectiveness and entry dynamics of a single-stage-to-orbit vehicle

NASA Technical Reports Server (NTRS)

Vinh, N. X.; Lin, C. F.

1982-01-01

The classical theory of flight dynamics for airplane longitudinal stability and control analysis was extended to the case of a hypervelocity reentry vehicle. This includes the elements inherent in supersonic and hypersonic flight such as the influence of the Mach number on aerodynamic characteristics, and the effect of the reaction control system and aerodynamic controls on the trim condition through a wide range of speed. Phugoid motion and angle of attack oscillation for typical cases of cruising flight, ballistic entry, and glide entry are investigated. In each case, closed form solutions for the variations in altitude, flight path angle, speed and angle of attack are obtained. The solutions explicitly display the influence of different regions design parameters and trajectory variables on the stability of the motion.

Understanding developmental language disorder - the Helsinki longitudinal SLI study (HelSLI): a study protocol.

PubMed

Laasonen, Marja; Smolander, Sini; Lahti-Nuuttila, Pekka; Leminen, Miika; Lajunen, Hanna-Reetta; Heinonen, Kati; Pesonen, Anu-Katriina; Bailey, Todd M; Pothos, Emmanuel M; Kujala, Teija; Leppänen, Paavo H T; Bartlett, Christopher W; Geneid, Ahmed; Lauronen, Leena; Service, Elisabet; Kunnari, Sari; Arkkila, Eva

2018-05-21

Developmental language disorder (DLD, also called specific language impairment, SLI) is a common developmental disorder comprising the largest disability group in pre-school-aged children. Approximately 7% of the population is expected to have developmental language difficulties. However, the specific etiological factors leading to DLD are not yet known and even the typical linguistic features appear to vary by language. We present here a project that investigates DLD at multiple levels of analysis and aims to make the reliable prediction and early identification of the difficulties possible. Following the multiple deficit model of developmental disorders, we investigate the DLD phenomenon at the etiological, neural, cognitive, behavioral, and psychosocial levels, in a longitudinal study of preschool children. In January 2013, we launched the Helsinki Longitudinal SLI study (HelSLI) at the Helsinki University Hospital ( http://tiny.cc/HelSLI ). We will study 227 children aged 3-6 years with suspected DLD and their 160 typically developing peers. Five subprojects will determine how the child's psychological characteristics and environment correlate with DLD and how the child's well-being relates to DLD, the characteristics of DLD in monolingual versus bilingual children, nonlinguistic cognitive correlates of DLD, electrophysiological underpinnings of DLD, and the role of genetic risk factors. Methods include saliva samples, EEG, computerized cognitive tasks, neuropsychological and speech and language assessments, video-observations, and questionnaires. The project aims to increase our understanding of the multiple interactive risk and protective factors that affect the developing heterogeneous cognitive and behavioral profile of DLD, including factors affecting literacy development. This accumulated knowledge will form a heuristic basis for the development of new interventions targeting linguistic and non-linguistic aspects of DLD.

Longitudinal brain white matter alterations in minimal hepatic encephalopathy before and after liver transplantation.

PubMed

Lin, Wei-Che; Chou, Kun-Hsien; Chen, Chao-Long; Chen, Hsiu-Ling; Lu, Cheng-Hsien; Li, Shau-Hsuan; Huang, Chu-Chung; Lin, Ching-Po; Cheng, Yu-Fan

2014-01-01

Cerebral edema is the common pathogenic mechanism for cognitive impairment in minimal hepatic encephalopathy. Whether complete reversibility of brain edema, cognitive deficits, and their associated imaging can be achieved after liver transplantation remains an open question. To characterize white matter integrity before and after liver transplantation in patients with minimal hepatic encephalopathy, multiple diffusivity indices acquired via diffusion tensor imaging was applied. Twenty-eight patients and thirty age- and sex-matched healthy volunteers were included. Multiple diffusivity indices were obtained from diffusion tensor images, including mean diffusivity, fractional anisotropy, axial diffusivity and radial diffusivity. The assessment was repeated 6-12 month after transplantation. Differences in white matter integrity between groups, as well as longitudinal changes, were evaluated using tract-based spatial statistical analysis. Correlation analyses were performed to identify first scan before transplantation and interval changes among the neuropsychiatric tests, clinical laboratory tests, and diffusion tensor imaging indices. After transplantation, decreased water diffusivity without fractional anisotropy change indicating reversible cerebral edema was found in the left anterior cingulate, claustrum, postcentral gyrus, and right corpus callosum. However, a progressive decrease in fractional anisotropy and an increase in radial diffusivity suggesting demyelination were noted in temporal lobe. Improved pre-transplantation albumin levels and interval changes were associated with better recoveries of diffusion tensor imaging indices. Improvements in interval diffusion tensor imaging indices in the right postcentral gyrus were correlated with visuospatial function score correction. In conclusion, longitudinal voxel-wise analysis of multiple diffusion tensor imaging indices demonstrated different white matter changes in minimal hepatic encephalopathy patients. Transplantation improved extracellular cerebral edema and the results of associated cognition tests. However, white matter demyelination may advance in temporal lobe.

The Second-Generation Maturation Inhibitor GSK3532795 Maintains Potent Activity Toward HIV Protease Inhibitor-Resistant Clinical Isolates.

PubMed

Ray, Neelanjana; Li, Tianbo; Lin, Zeyu; Protack, Tricia; van Ham, Petronella Maria; Hwang, Carey; Krystal, Mark; Nijhuis, Monique; Lataillade, Max; Dicker, Ira

2017-05-01

Protease inhibitor (PI)-resistant HIV-1 isolates with primary substitutions in protease (PR) and secondary substitutions in Gag could potentially exhibit cross-resistance to maturation inhibitors. We evaluated the second-generation maturation inhibitor, GSK3532795, for activity toward clinical isolates with genotypic and phenotypic characteristics associated with PI resistance (longitudinal). Longitudinal clinical isolates from 15 PI-treated patients and 7 highly PI-resistant (nonlongitudinal) viruses containing major and minor PI resistance-associated mutations were evaluated for GSK3532795 sensitivity. Phenotypic sensitivity was determined using the PhenoSense Gag/PR assay (Monogram Biosciences) or in-house single- and multiple-cycle assays. Changes from baseline [CFB; ratio of post- to pre-treatment FC-IC50 (fold-change in IC50 versus wild-type virus)] <3 were considered to be within the no-effect level. All nonlongitudinal viruses tested were sensitive to GSK3532795 (FC-IC50 range 0.16-0.68). Among longitudinal isolates, all post-PI treatment samples had major PI resistance-associated mutations in PR and 17/21 had PI resistance-associated changes in Gag. Nineteen of the 21 post-PI treatment samples had GSK3532795 CFB <3. Median (range) CFB was 0.83 (0.05-27.4) [Monogram (11 patients)] and 1.5 (1.0-2.2) [single-cycle (4 patients)]. The 2 post-PI treatment samples showing GSK3532795 CFB >3 (Monogram) were retested using single- and multiple-cycle assays. Neither sample had meaningful sensitivity changes in the multiple-cycle assay. Gag changes were not associated with an increased GSK3532795 CFB. GSK3532795 maintained antiviral activity against PI-resistant isolates with emergent PR and/or Gag mutations. This finding supports continued development of GSK3532795 in treatment-experienced patients with or without previous PI therapy.

Longitudinal Relationship Between Psychological Distress and Multiple Substance Use: Results From a Three-Year Multisite Natural-History Study of Rural Stimulant Users*

PubMed Central

Booth, Brenda M.; Curran, Geoffrey; Han, Xiaotong; Wright, Patricia; Frith, Sarah; Leukefeld, Carl; Falck, Russel; Carlson, Robert G.

2010-01-01

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. PMID:20230724

A longitudinal model for functional connectivity networks using resting-state fMRI.

PubMed

Hart, Brian; Cribben, Ivor; Fiecas, Mark

2018-06-04

Many neuroimaging studies collect functional magnetic resonance imaging (fMRI) data in a longitudinal manner. However, the current fMRI literature lacks a general framework for analyzing functional connectivity (FC) networks in fMRI data obtained from a longitudinal study. In this work, we build a novel longitudinal FC model using a variance components approach. First, for all subjects' visits, we account for the autocorrelation inherent in the fMRI time series data using a non-parametric technique. Second, we use a generalized least squares approach to estimate 1) the within-subject variance component shared across the population, 2) the baseline FC strength, and 3) the FC's longitudinal trend. Our novel method for longitudinal FC networks seeks to account for the within-subject dependence across multiple visits, the variability due to the subjects being sampled from a population, and the autocorrelation present in fMRI time series data, while restricting the number of parameters in order to make the method computationally feasible and stable. We develop a permutation testing procedure to draw valid inference on group differences in the baseline FC network and change in FC over longitudinal time between a set of patients and a comparable set of controls. To examine performance, we run a series of simulations and apply the model to longitudinal fMRI data collected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Overall, we found no difference in the global FC network between Alzheimer's disease patients and healthy controls, but did find differing local aging patterns in the FC between the left hippocampus and the posterior cingulate cortex. Copyright © 2018 Elsevier Inc. All rights reserved.

Change in Psychosocial Health Status Over 5 Years in Relation to Adults' Hearing Ability in Noise.

PubMed

Stam, Mariska; Smit, Jan H; Twisk, Jos W R; Lemke, Ulrike; Smits, Cas; Festen, Joost M; Kramer, Sophia E

The aim of this study was to establish the longitudinal relationship between hearing ability in noise and psychosocial health outcomes (i.e., loneliness, anxiety, depression, distress, and somatization) in adults aged 18 to 70 years. An additional objective was to determine whether a change in hearing ability in noise over a period of 5 years was associated with a change in psychosocial functioning. Subgroup effects for a range of factors were investigated. Longitudinal data of the web-based Netherlands Longitudinal Study on Hearing (NL-SH) (N = 508) were analyzed. The ability to recognize speech in noise (i.e., the speech-reception-threshold [SRTn]) was measured with an online digit triplet test at baseline and at 5-year follow-up. Psychosocial health status was assessed by online questionnaires. Multiple linear regression analyses and longitudinal statistical analyses (i.e., generalized estimating equations) were performed. Poorer SRTn was associated longitudinally with more feelings of emotional and social loneliness. For participants with a high educational level, the longitudinal association between SRTn and social loneliness was significant. Changes in hearing ability and loneliness appeared significantly associated only for specific subgroups: those with stable pattern of hearing aid nonuse (increased emotional and social loneliness), who entered matrimony (increased social loneliness), and low educational level (less emotional loneliness). No significant longitudinal associations were found between hearing ability and anxiety, depression, distress, or somatization. Hearing ability in noise was longitudinally associated with loneliness. Decline in hearing ability in noise was related to increase in loneliness for specific subgroups of participants. One of these subgroups included participants whose hearing deteriorated over 5 years, but who continued to report nonuse of hearing aids. This is an important and alarming finding that needs further investigation.

Longitudinal comparative evaluation of the equivalence of an integrated peer-support and clinical staffing model for residential mental health rehabilitation: a mixed methods protocol incorporating multiple stakeholder perspectives.

PubMed

Parker, Stephen; Dark, Frances; Newman, Ellie; Korman, Nicole; Meurk, Carla; Siskind, Dan; Harris, Meredith

2016-06-02

A novel staffing model integrating peer support workers and clinical staff within a unified team is being trialled at community based residential rehabilitation units in Australia. A mixed-methods protocol for the longitudinal evaluation of the outcomes, expectations and experiences of care by consumers and staff under this staffing model in two units will be compared to one unit operating a traditional clinical staffing. The study is unique with regards to the context, the longitudinal approach and consideration of multiple stakeholder perspectives. The longitudinal mixed methods design integrates a quantitative evaluation of the outcomes of care for consumers at three residential rehabilitation units with an applied qualitative research methodology. The quantitative component utilizes a prospective cohort design to explore whether equivalent outcomes are achieved through engagement at residential rehabilitation units operating integrated and clinical staffing models. Comparative data will be available from the time of admission, discharge and 12-month period post-discharge from the units. Additionally, retrospective data for the 12-month period prior to admission will be utilized to consider changes in functioning pre and post engagement with residential rehabilitation care. The primary outcome will be change in psychosocial functioning, assessed using the total score on the Health of the Nation Outcome Scales (HoNOS). Planned secondary outcomes will include changes in symptomatology, disability, recovery orientation, carer quality of life, emergency department presentations, psychiatric inpatient bed days, and psychological distress and wellbeing. Planned analyses will include: cohort description; hierarchical linear regression modelling of the predictors of change in HoNOS following CCU care; and descriptive comparisons of the costs associated with the two staffing models. The qualitative component utilizes a pragmatic approach to grounded theory, with collection of data from consumers and staff at multiple time points exploring their expectations, experiences and reflections on the care provided by these services. It is expected that the new knowledge gained through this study will guide the adaptation of these and similar services. For example, if differential outcomes are achieved for consumers under the integrated and clinical staffing models this may inform staffing guidelines.

Tailored Panel Management: A Theory-Based Approach to Building and Maintaining Participant Commitment to a Longitudinal Study.

PubMed

Estrada, Mica; Woodcock, Anna; Schultz, P Wesley

2014-02-01

Many psychological processes unfold over time, necessitating longitudinal research designs. Longitudinal research poses a host of methodological challenges, foremost of which is participant attrition. Building on Dillman's work, we provide a review of how social influence and relationship research informs retention strategies in longitudinal studies. Objective: We introduce the tailored panel management (TPM) approach, which is designed to establish communal norms that increase commitment to a longitudinal study, and this commitment, in turn, increases response rates and buffers against attrition. Specifically, we discuss practices regarding compensation, communication, consistency, and credibility that increase longer term commitment to panel participation. Research design: Throughout the article, we describe how TPM is being used in a national longitudinal study of undergraduate minority science students. TheScienceStudy is a continuing panel, which has 12 waves of data collected across 6 academic years, with response rates ranging from 70% to 92%. Although more than 90% of participants have either left or graduated from their undergraduate degree program, this highly mobile group of people remains engaged in the study. TheScienceStudy has usable longitudinal data from 96% of the original panel. Conclusion: This article combines social psychological theory, current best practice, and a detailed case study to illustrate the TPM approach to longitudinal data collection. The approach provides guidance for other longitudinal researchers, and advocates for empirical research into longitudinal research methodologies. © The Author(s) 2014.

What Happens to a Nursing Home Chain When Private Equity Takes Over? A Longitudinal Case Study.

PubMed

Bos, Aline; Harrington, Charlene

2017-01-01

We analyzed what happens to a nursing home chain when private equity takes over, with regard to strategy, financial performance, and resident well-being. We conducted a longitudinal (2000-2012) case study of a large nursing home chain that triangulated qualitative and quantitative data from 5 different data sources. Results show that private equity owners continued and reinforced several strategies that were already put in place before the takeover, including a focus on keeping staffing levels low; the new owners added restructuring, rebranding, and investment strategies such as establishing new companies, where the nursing home chain served as an essential "launch customer."

Longitudinal assessment of short-term memory deterioration in a logopenic variant primary progressive aphasia with post-mortem confirmed Alzheimer's Disease pathology.

PubMed

Tree, Jeremy; Kay, Janice

2015-09-01

In the field of dementia research, there are reports of neurodegenerative cases with a focal loss of language, termed primary progressive aphasia (PPA). Currently, this condition has been further sub-classified, with the most recent sub-type dubbed logopenic variant (PPA-LV). As yet, there remains somewhat limited evaluation of the characteristics of this condition, with no studies providing longitudinal assessment accompanied by post-mortem examination. Moreover, a key characteristic of the PPA-LV case is a deterioration of phonological short-term memory, but again little work has scrutinized the nature of this impairment over time. The current study seeks to redress these oversights and presents detailed longitudinal examination of language and memory function in a case of PPA-LV, with special focus on tests linked to components of phonological short-term memory function. Our findings are then considered with reference to a contemporary model of the neuropsychology of phonological short-term memory. Additionally, post-mortem examinations indicated Alzheimer's disease type pathology, providing further evidence that the PPA-LV presentation may reflect an atypical presentation of this condition. © 2014 The British Psychological Society.

Longitudinal patient-oriented outcomes in neuropathy

PubMed Central

Kerber, Kevin; Langa, Kenneth M.; Banerjee, Mousumi; Rodgers, Ann; McCammon, Ryan; Burke, James; Feldman, Eva

2015-01-01

Objective: To evaluate longitudinal patient-oriented outcomes in peripheral neuropathy over a 14-year time period including time before and after diagnosis. Methods: The 1996–2007 Health and Retirement Study (HRS)–Medicare Claims linked database identified incident peripheral neuropathy cases (ICD-9 codes) in patients ≥65 years. Using detailed demographic information from the HRS and Medicare claims, a propensity score method identified a matched control group without neuropathy. Patient-oriented outcomes, with an emphasis on self-reported falls, pain, and self-rated health (HRS interview), were determined before and after neuropathy diagnosis. Generalized estimating equations were used to assess differences in longitudinal outcomes between cases and controls. Results: We identified 953 peripheral neuropathy cases and 953 propensity-matched controls. The mean (SD) age was 77.4 (6.7) years for cases, 76.9 (6.6) years for controls, and 42.1% had diabetes. Differences were detected in falls 3.0 years before neuropathy diagnosis (case vs control; 32% vs 25%, p = 0.008), 5.0 years for pain (36% vs 27%, p = 0.002), and 5.0 years for good to excellent self-rated health (61% vs 74%, p < 0.0001). Over time, the proportion of fallers increased more rapidly in neuropathy cases compared to controls (p = 0.002), but no differences in pain (p = 0.08) or self-rated health (p = 0.9) were observed. Conclusions: In older persons, differences in falls, pain, and self-rated health can be detected 3–5 years prior to peripheral neuropathy diagnosis, but only falls deteriorates more rapidly over time in neuropathy cases compared to controls. Interventions to improve early peripheral neuropathy detection are needed, and future clinical trials should incorporate falls as a key patient-oriented outcome. PMID:26019191

Longitudinal evaluation of corticospinal tract in patients with resected brainstem cavernous malformations using high-definition fiber tractography and diffusion connectometry analysis: preliminary experience.

PubMed

Faraji, Amir H; Abhinav, Kumar; Jarbo, Kevin; Yeh, Fang-Cheng; Shin, Samuel S; Pathak, Sudhir; Hirsch, Barry E; Schneider, Walter; Fernandez-Miranda, Juan C; Friedlander, Robert M

2015-11-01

Brainstem cavernous malformations (CMs) are challenging due to a higher symptomatic hemorrhage rate and potential morbidity associated with their resection. The authors aimed to preoperatively define the relationship of CMs to the perilesional corticospinal tracts (CSTs) by obtaining qualitative and quantitative data using high-definition fiber tractography. These data were examined postoperatively by using longitudinal scans and in relation to patients' symptomatology. The extent of involvement of the CST was further evaluated longitudinally using the automated "diffusion connectometry" analysis. Fiber tractography was performed with DSI Studio using a quantitative anisotropy (QA)-based generalized deterministic tracking algorithm. Qualitatively, CST was classified as being "disrupted" and/or "displaced." Quantitative analysis involved obtaining mean QA values for the CST and its perilesional and nonperilesional segments. The contralateral CST was used for comparison. Diffusion connectometry analysis included comparison of patients' data with a template from 90 normal subjects. Three patients (mean age 22 years) with symptomatic pontomesencephalic hemorrhagic CMs and varying degrees of hemiparesis were identified. The mean follow-up period was 37.3 months. Qualitatively, CST was partially disrupted and displaced in all. Direction of the displacement was different in each case and progressively improved corresponding with the patient's neurological status. No patient experienced neurological decline related to the resection. The perilesional mean QA percentage decreases supported tract disruption and decreased further over the follow-up period (Case 1, 26%-49%; Case 2, 35%-66%; and Case 3, 63%-78%). Diffusion connectometry demonstrated rostrocaudal involvement of the CST consistent with the quantitative data. Hemorrhagic brainstem CMs can disrupt and displace perilesional white matter tracts with the latter occurring in unpredictable directions. This requires the use of tractography to accurately define their orientation to optimize surgical entry point, minimize morbidity, and enhance neurological outcomes. Observed anisotropy decreases in the perilesional segments are consistent with neural injury following hemorrhagic insults. A model using these values in different CST segments can be used to longitudinally monitor its craniocaudal integrity. Diffusion connectometry is a complementary approach providing longitudinal information on the rostrocaudal involvement of the CST.

3D-MICE: integration of cross-sectional and longitudinal imputation for multi-analyte longitudinal clinical data.

PubMed

Luo, Yuan; Szolovits, Peter; Dighe, Anand S; Baron, Jason M

2018-06-01

A key challenge in clinical data mining is that most clinical datasets contain missing data. Since many commonly used machine learning algorithms require complete datasets (no missing data), clinical analytic approaches often entail an imputation procedure to "fill in" missing data. However, although most clinical datasets contain a temporal component, most commonly used imputation methods do not adequately accommodate longitudinal time-based data. We sought to develop a new imputation algorithm, 3-dimensional multiple imputation with chained equations (3D-MICE), that can perform accurate imputation of missing clinical time series data. We extracted clinical laboratory test results for 13 commonly measured analytes (clinical laboratory tests). We imputed missing test results for the 13 analytes using 3 imputation methods: multiple imputation with chained equations (MICE), Gaussian process (GP), and 3D-MICE. 3D-MICE utilizes both MICE and GP imputation to integrate cross-sectional and longitudinal information. To evaluate imputation method performance, we randomly masked selected test results and imputed these masked results alongside results missing from our original data. We compared predicted results to measured results for masked data points. 3D-MICE performed significantly better than MICE and GP-based imputation in a composite of all 13 analytes, predicting missing results with a normalized root-mean-square error of 0.342, compared to 0.373 for MICE alone and 0.358 for GP alone. 3D-MICE offers a novel and practical approach to imputing clinical laboratory time series data. 3D-MICE may provide an additional tool for use as a foundation in clinical predictive analytics and intelligent clinical decision support.

Resilience Mediates the Longitudinal Relationships Between Social Support and Mental Health Outcomes in Multiple Sclerosis.

PubMed

Koelmel, Emily; Hughes, Abbey J; Alschuler, Kevin N; Ehde, Dawn M

2017-06-01

To investigate the longitudinal relationships between social support and subsequent mental health outcomes in individuals with multiple sclerosis (MS), and to examine resilience as a mediator between social support and subsequent mental health outcomes in this population. Observational, longitudinal cohort study. Participants were assessed at 4 time points over 12 months in the context of a previously reported randomized controlled trial. Telephone-based measures administered to community-based participants. Individuals (N=163) with MS and 1 or more of the following symptoms: depression, fatigue, and pain. Not applicable. Mental health outcomes included (1) depressive symptomatology, assessed using the Patient Health Questionnaire-9; (2) anxious symptomatology, assessed using the short form of the Emotional Distress-Anxiety Scale from the Patient-Reported Outcomes Measurement Information System; and (3) general mental health status, assessed using the Mental Component Summary score from the Short Form-8 Health Survey. Resilience was assessed using the Connor-Davidson Resilience Scale. At any given time, social support from significant others, family members, and friends was significantly associated with subsequent mental health outcomes for all 3 measures assessed (all P values <.05). Resilience measured concomitantly with social support significantly mediated the relationships between social support and subsequent mental health outcomes. After controlling for resilience, most of the direct relationships between social support and mental health outcomes were no longer significant. There are significant longitudinal relationships between social support, resilience, and mental health outcomes for people with MS. Given the mediating role of resilience in supporting better mental health outcomes, future clinical research and practice may benefit from an emphasis on resilience-focused psychological interventions. Copyright © 2016 American Congress of Rehabilitation Medicine. All rights reserved.

Longitudinal, transcranial measurement of functional activation in the rat brain by diffuse correlation spectroscopy.

PubMed

Blanco, Igor; Zirak, Peyman; Dragojević, Tanja; Castellvi, Clara; Durduran, Turgut; Justicia, Carles

2017-10-01

Neural activity is an important biomarker for the presence of neurodegenerative diseases, cerebrovascular alterations, and brain trauma; furthermore, it is a surrogate marker for treatment effects. These pathologies may occur and evolve in a long time-period, thus, noninvasive, transcutaneous techniques are necessary to allow a longitudinal follow-up. In the present work, we have customized noninvasive, transcutaneous, diffuse correlation spectroscopy (DCS) to localize changes in cerebral blood flow (CBF) induced by neural activity. We were able to detect changes in CBF in the somatosensory cortex by using a model of electrical forepaw stimulation in rats. The suitability of DCS measurements for longitudinal monitoring was demonstrated by performing multiple sessions with the same animals at different ages (from 6 to 18 months). In addition, functional DCS has been cross-validated by comparison with functional magnetic resonance imaging (fMRI) in the same animals in a subset of the time-points. The overall results obtained with transcutaneous DCS demonstrates that it can be utilized in longitudinal studies safely and reproducibly to locate changes in CBF induced by neural activity in the small animal brain.

Measuring change for a multidimensional test using a generalized explanatory longitudinal item response model.

PubMed

Cho, Sun-Joo; Athay, Michele; Preacher, Kristopher J

2013-05-01

Even though many educational and psychological tests are known to be multidimensional, little research has been done to address how to measure individual differences in change within an item response theory framework. In this paper, we suggest a generalized explanatory longitudinal item response model to measure individual differences in change. New longitudinal models for multidimensional tests and existing models for unidimensional tests are presented within this framework and implemented with software developed for generalized linear models. In addition to the measurement of change, the longitudinal models we present can also be used to explain individual differences in change scores for person groups (e.g., learning disabled students versus non-learning disabled students) and to model differences in item difficulties across item groups (e.g., number operation, measurement, and representation item groups in a mathematics test). An empirical example illustrates the use of the various models for measuring individual differences in change when there are person groups and multiple skill domains which lead to multidimensionality at a time point. © 2012 The British Psychological Society.

Human Behavior, Learning, and the Developing Brain: Typical Development

ERIC Educational Resources Information Center

Coch, Donna, Ed.; Fischer, Kurt W., Ed.; Dawson, Geraldine, Ed.

2010-01-01

This volume brings together leading authorities from multiple disciplines to examine the relationship between brain development and behavior in typically developing children. Presented are innovative cross-sectional and longitudinal studies that shed light on brain-behavior connections in infancy and toddlerhood through adolescence. Chapters…

Perceived Sibling Relationships and Adolescent Development.

ERIC Educational Resources Information Center

Yeh, Hsiu-Chen; Lempers, Jacques D.

2004-01-01

Utilizing longitudinal, 3-wave data collected from multiple informants (fathers, mothers, and target children) in 374 families, the potential effects of sibling relationships on adolescent development across early and middle adolescence were investigated. Adolescents who perceived their sibling relationships more positively at Time 1 tended to…

How Do We Match Instructional Effectiveness with Learning Curves?

ERIC Educational Resources Information Center

Branum-Martin, Lee; Mehta, Paras D.; Taylor, W. Patrick; Carlson, Coleen D.; Lei, Xiaoxuan; Hunter, C. Vincent; Francis, David J.

2015-01-01

In order to examine the effectiveness of instruction, the authors confront formidable statistical problems, including multivariate structure of classroom observations, longitudinal dependence of both classroom observations and student outcomes. As the authors begin to examine instruction, classroom observations involve multiple variables for which…

Mental and Motor Growth Patterns and Growth Velocity of Indian Babies. (Longitudinal Growth of Indian Children). Research Report No. 4.

ERIC Educational Resources Information Center

Phatak, Pramila; And Others

This study reports various aspects of the analyses carried out on the longitudinal data reported in a previous study (PS 007 345) for determining the general growth patterns and growth velocity of mental and motor development. Preliminary analyses focused on the selection of the growth curve, its evaluation in the 208 individual cases, and the…

49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a water... a maximum wall stress of 24,000 p.s.i. in the formula described in paragraph (f)(4) of this section... any case the minimum wall thickness must be such that the wall stress calculated by the formula listed...

49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

Code of Federal Regulations, 2010 CFR

2010-10-01

... DOT 4BW cylinder is a welded type steel cylinder with a longitudinal electric-arc welded seam, a water... a maximum wall stress of 24,000 p.s.i. in the formula described in paragraph (f)(4) of this section... any case the minimum wall thickness must be such that the wall stress calculated by the formula listed...

Vowel Development in an Emergent Mandarin-English Bilingual Child: A Longitudinal Study

ERIC Educational Resources Information Center

Yang, Jing; Fox, Robert A.; Jacewicz, Ewa

2015-01-01

This longitudinal case study documents the emergence of bilingualism in a young monolingual Mandarin boy on the basis of an acoustic analysis of his vowel productions recorded via a picture-naming task over 20 months following his enrollment in an all-English (L2) preschool at the age of 3;7. The study examined (1) his initial L2 vowel space, (2)…

A Longitudinal Study of the Educational and Career Trajectories of Female Participants of an Urban Informal Science Education Program

ERIC Educational Resources Information Center

Fadigan, Kathleen A.; Hammrich, Penny L.

2004-01-01

The purpose of this longitudinal case study is to describe the educational trajectories of a sample of 152 young women from urban, low-income, single-parent families who participated in the Women in Natural Sciences (WINS) program during high school. Utilizing data drawn from program records, surveys, and interviews, this study also attempts to…

Second Language Acquisition at the Early Childhood Level: A 5-Year Longitudinal Case Study of Pre-Kindergarten through First-Grade Students

ERIC Educational Resources Information Center

Billak, Bonnie

2013-01-01

This 5-year longitudinal study investigated the English language acquisition and development of students in pre-Kindergarten through Grade 1 at a U.S.-accredited international school. Of the 1,509 students tested, the overwhelming majority were nonnative English speakers. The data provide valuable insight into the rate of second language…

Assessing the Impact of Research: A Case Study of the LSAY Research Innovation and Expansion Fund. Longitudinal Surveys of Australian Youth. Occasional Paper

ERIC Educational Resources Information Center

Hargreaves, Jo

2012-01-01

The purpose of this project is to apply the framework developed by the National Centre for Vocational Education Research (NCVER) for measuring research impact to assess the outcomes of the research and activities funded under the Longitudinal Surveys of Australian Youth (LSAY) Research Innovation and Expansion Fund (RIEF). LSAY provides a rich…

Achievement, motivation, and educational choices: A longitudinal study of expectancy and value using a multiplicative perspective.

PubMed

Guo, Jiesi; Parker, Philip D; Marsh, Herbert W; Morin, Alexandre J S

2015-08-01

Drawing on the expectancy-value model, the present study explored individual and gender differences in university entry and selection of educational pathway (e.g., science, technology, engineering, and mathematics [STEM] course selection). In particular, we examined the multiplicative effects of expectancy and task values on educational outcomes during the transition into early adulthood. Participants were from a nationally representative longitudinal sample of 15-year-old Australian youths (N = 10,370). The results suggest that (a) both math self-concept and intrinsic value interact in predicting advanced math course selection, matriculation results, entrance into university, and STEM fields of study; (b) prior reading achievement has negative effects on advanced math course selection and STEM fields through math motivational beliefs; and (c) gender differences in educational outcomes are mediated by gender differences in motivational beliefs and prior academic achievement, while the processes underlying choice of educational pathway were similar for males and females. (c) 2015 APA, all rights reserved).

Efficacy of treatment of trochanteric bursitis: a systematic review.

PubMed

Lustenberger, David P; Ng, Vincent Y; Best, Thomas M; Ellis, Thomas J

2011-09-01

Trochanteric bursitis (TB) is a self-limiting disorder in the majority of patients and typically responds to conservative measures. However, multiple courses of nonoperative treatment or surgical intervention may be necessary in refractory cases. The purpose of this systematic review was to evaluate the efficacy of the treatment of TB. A literature search in the PubMed, MEDLINE, CINAHL, and ISI Web of Knowledge databases was performed for all English language studies up to April 2010. Terms combined in a Boolean search were greater trochanteric pain syndrome, trochanteric bursitis, trochanteric, bursitis, surgery, therapy, drug therapy, physical therapy, rehabilitation, injection, Z-plasty, Z-lengthening, aspiration, bursectomy, bursoscopy, osteotomy, and tendon repair. All studies directly involving the treatment of TB were reviewed by 2 authors and selected for further analysis. Expert opinion and review articles were excluded, as well as case series with fewer than 5 patients. Twenty-four articles were identified. According to the system described by Wright et al, 2 studies, each with multiple arms, qualified as level I evidence, 1 as level II, 1 as level III, and the rest as level IV. More than 950 cases were included. The authors extracted data regarding the type of intervention, level of evidence, mean age of patients, patient gender, number of hips in the study, symptom duration before the study, mean number of injections before the study, prior hip surgeries, patient satisfaction, length of follow-up, baseline scores, and follow-up scores for the visual analog scale (VAS) and Harris Hip Scores (HHS). Symptom resolution and the ability to return to activity ranged from 49% to 100% with corticosteroid injection as the primary treatment modality with and without multimodal conservative therapy. Two comparative studies (levels II and III) found low-energy shock-wave therapy (SWT) to be superior to other nonoperative modalities. Multiple surgical options for persistent TB have been reported, including bursectomy (n = 2), longitudinal release of the iliotibial band (n = 2), proximal or distal Z-plasty (n = 4), osteotomy (n = 1), and repair of gluteus medius tears (n = 4). Efficacy among surgical techniques varied depending on the clinical outcome measure, but all were superior to corticosteroid therapy and physical therapy according to the VAS and HHS in both comparison studies and between studies. This systematic review found that traditional nonoperative treatment helped most patients, SWT was a good alternative, and surgery was effective in refractory cases.

78 FR 15279 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-11

... altimeter with engaged flare and retard mode, in case of go-around, might lead to a temporary loss of... flare and retard mode, in case of go-around, the situation may lead to a temporary loss of aeroplane... and retard mode, in case of go-around, might lead to a temporary loss of airplane longitudinal control...

FUEL ROD CLUSTERS

DOEpatents

Schultz, A.B.

1959-08-01

A cluster of nuclear fuel rods and a tubular casing therefor through which a coolant flows in heat-exchange contact with the fuel rods is described. The fuel rcds are held in the casing by virtue of the compressive force exerted between longitudinal ribs of the fuel rcds and internal ribs of the casing or the internal surfaces thereof.

Description of congenital hand anomalies: a personal view.

PubMed

Tonkin, M A

2006-10-01

A series of four congenital hand cases exhibiting central clefting are presented. The cases are morphologically similar and exhibit characteristics of both symbrachydactyly and central longitudinal deficiency. The cases demonstrate difficulties in classification by either the IFSSH classification system or the JSSH modification of it. An alternative descriptive approach to classification is suggested.

Parental feeding style, energy intake and weight status in young Scottish children.

PubMed

Montgomery, Colette; Jackson, Diane M; Kelly, Louise A; Reilly, John J

2006-12-01

Parental feeding style, as measured by the Child Feeding Questionnaire (CFQ), may be an important influence on child feeding behaviour and weight status in early to mid childhood, but more evidence on parental feeding style is required from samples outside the USA. We aimed to use the CFQ in a sample of 117 Scottish children (boys n 53, girls n 64 mean age 4.6 (SD 0.5) years) to: characterise gender differences and changes over time (in forty of the 117 children studied over 2 years); test associations between parental feeding style, free-living energy intake (measured over 3 days using the multiple pass 24-h recall), and weight status (BMI SD score). No dimensions of parental feeding style changed significantly over 2 years in the longitudinal study (P>0.05 in all cases). No aspects of parental feeding style as measured by the CFQ differed significantly between the sexes (P>0.05 in all cases). Parental perceptions of child weight status were generally significantly positively correlated with child weight status as measured by the BMI SD score. In this sample and setting, measures of parental control over child feeding were generally not associated with child energy intake or weight status.

Team Leadership and Cancer End-of-Life Decision Making.

PubMed

Waldfogel, Julie M; Battle, Dena J; Rosen, Michael; Knight, Louise; Saiki, Catherine B; Nesbit, Suzanne A; Cooper, Rhonda S; Browner, Ilene S; Hoofring, Laura H; Billing, Lynn S; Dy, Sydney M

2016-11-01

End-of-life decision making in cancer can be a complicated process. Patients and families encounter multiple providers throughout their cancer care. When the efforts of these providers are not well coordinated in teams, opportunities for high-quality, longitudinal goals of care discussions can be missed. This article reviews the case of a 55-year-old man with lung cancer, illustrating the barriers and missed opportunities for end-of-life decision making in his care through the lens of team leadership, a key principle in the science of teams. The challenges demonstrated in this case reflect the importance of the four functions of team leadership: information search and structuring, information use in problem solving, managing personnel resources, and managing material resources. Engaging in shared leadership of these four functions can help care providers improve their interactions with patients and families concerning end-of-life care decision making. This shared leadership can also produce a cohesive care plan that benefits from the expertise of the range of available providers while reflecting patient needs and preferences. Clinicians and researchers should consider the roles of team leadership functions and shared leadership in improving patient care when developing and studying models of cancer care delivery.

A Pilot Study to Examine Maturation of Body Temperature Control in Preterm Infants

PubMed Central

Knobel, Robin B.; Levy, Janet; Katz, Laurence; Guenther, Bob; Holditch-Davis, Diane

2013-01-01

Objective To test instrumentation and develop analytic models to use in a larger study to examine developmental trajectories of body temperature and peripheral perfusion from birth in extremely low birth weight (EBLW) infants. Design A case study design. Setting The study took place in a level four neonatal intensive care unit (NICU) in North Carolina. Participants Four ELBW infants, less than 29 weeks gestational age at birth. Methods Physiologic data were measured every minute for the first 5 days of life: peripheral perfusion using perfusion index by Masimo and body temperature using thermistors. Body temperature was also measured using infrared thermal imaging. Stimulation and care events were recorded over the first 5 days using video which was coded with Noldus Observer software. Novel analytical models using the state space approach to time series analysis were developed to explore maturation of neural control over central and peripheral body temperature. Results/Conclusion Results from this pilot study confirmed the feasibility of using multiple instruments to measure temperature and perfusion in ELBW infants. This approach added rich data to our case study design and set a clinical context with which to interpret longitudinal physiological data. PMID:24004312

An educational strategy for treating chronic, noncancer pain with opioids: a pilot test.

PubMed

Elhwairis, Huda; Reznich, Christopher B

2010-12-01

Chronic pain is common and can be devastating to the patient and challenging to the health care provider. Despite the importance of the topic, pain management curricula are incomplete in health professionals' training. We developed a longitudinal curriculum to teach therapy for chronic noncancer pain over four units and pilot-tested the teaching of one unit (opioids) to internal medicine residents. The educational strategies we used included didactic sessions, write-up of a management plan following a model, case discussions, and role-play group activities. We pilot-tested one unit (opioid therapy) in March 2008. We performed learner evaluations, using a pretest and posttest, a write-up plan following a model, and a learner knowledge questionnaire. Results showed significant improvement in knowledge. Residents found the sessions and educational strategy to be excellent and reported higher confidence levels in managing patients with chronic noncancer pain. This article demonstrates that multiple teaching modalities-including didactic lectures, case discussions, write-up of a management plan following a model, and role-play group activities-are effective methods of teaching internal medicine residents how to use opioids to manage chronic noncancer pain. Copyright © 2010 American Pain Society. Published by Elsevier Inc. All rights reserved.

Investigation of the Multiple Method Adaptive Control (MMAC) method for flight control systems

NASA Technical Reports Server (NTRS)

Athans, M.; Baram, Y.; Castanon, D.; Dunn, K. P.; Green, C. S.; Lee, W. H.; Sandell, N. R., Jr.; Willsky, A. S.

1979-01-01

The stochastic adaptive control of the NASA F-8C digital-fly-by-wire aircraft using the multiple model adaptive control (MMAC) method is presented. The selection of the performance criteria for the lateral and the longitudinal dynamics, the design of the Kalman filters for different operating conditions, the identification algorithm associated with the MMAC method, the control system design, and simulation results obtained using the real time simulator of the F-8 aircraft at the NASA Langley Research Center are discussed.

The stochastic control of the F-8C aircraft using the Multiple Model Adaptive Control (MMAC) method

NASA Technical Reports Server (NTRS)

Athans, M.; Dunn, K. P.; Greene, E. S.; Lee, W. H.; Sandel, N. R., Jr.

1975-01-01

The purpose of this paper is to summarize results obtained for the adaptive control of the F-8C aircraft using the so-called Multiple Model Adaptive Control method. The discussion includes the selection of the performance criteria for both the lateral and the longitudinal dynamics, the design of the Kalman filters for different flight conditions, the 'identification' aspects of the design using hypothesis testing ideas, and the performance of the closed loop adaptive system.

Longitudinal MR cortical thinning of individuals and its correlation with PET metabolic reduction: a measurement consistency and correctness studies

NASA Astrophysics Data System (ADS)

Lin, Zhongmin S.; Avinash, Gopal; McMillan, Kathryn; Yan, Litao; Minoshima, Satoshi

2014-03-01

Cortical thinning and metabolic reduction can be possible imaging biomarkers for Alzheimer's disease (AD) diagnosis and monitoring. Many techniques have been developed for the cortical measurement and widely used for the clinical statistical studies. However, the measurement consistency of individuals, an essential requirement for a clinically useful technique, requires proper further investigation. Here we leverage our previously developed BSIM technique 1 to measure cortical thickness and thinning and use it with longitudinal MRI from ADNI to investigate measurement consistency and spatial resolution. 10 normal, 10 MCI, and 10 AD subjects in their 70s were selected for the study. Consistent cortical thinning patterns were observed in all baseline and follow up images. Rapid cortical thinning was shown in some MCI and AD cases. To evaluate the correctness of the cortical measurement, we compared longitudinal cortical thinning with clinical diagnosis and longitudinal PET metabolic reduction measured using 3D-SSP technique2 for the same person. Longitudinal MR cortical thinning and corresponding PET metabolic reduction showed high level pattern similarity revealing certain correlations worthy of further studies. Severe cortical thinning that might link to disease conversion from MCI to AD was observed in two cases. In summary, our results suggest that consistent cortical measurements using our technique may provide means for clinical diagnosis and monitoring at individual patient's level and MR cortical thinning measurement can complement PET metabolic reduction measurement.

Prevalence of associated extracardiac malformations in the congenital heart disease population.

PubMed

Egbe, Alexander; Uppu, Santosh; Lee, Simon; Ho, Deborah; Srivastava, Shubhika

2014-10-01

The authors hypothesized that changes in prenatal factors such as termination of pregnancy for fetal anomalies and prenatal vitamin supplementation have altered the epidemiology of patients with multiple congenital anomalies and may have had an impact on their prevalence in the current era. This study reviewed the Nationwide Inpatient Sample database from 1998 to 2008 and compared the prevalence of ECM among live births with a CHD diagnosis (case) and that among live births without a CHD diagnosis (control). For this study, 42 ECM and 10 CHD diagnoses were selected for subanalysis. Longitudinal analysis also was performed to determine temporal variation of ECM prevalence in the CHD population during the 11-year study period. The cohort in this study consisted of 97,154 patients in the case group and 12,078,482 subjects in the control group. The prevalences in the CHD population were 11.4 % for nonsyndromic congenital malformation (NSCM), 2.2 % for genetic syndrome (GS), and 13.6 % for overall extracardiac congenital malformation (ECM). The prevalences in the control group were 6.7 % for NSCM, 0.3 % for GS, and 7.0 % for ECM. The findings showed a strong association of NSCM [odds ratio (OR) 1.88; 95 % confidence interval (CI) 1.73-1.94], GS (OR 2.52; 95 % CI 2.44-2.61), and overall ECM (OR 2.01; 95 % CI 1.97-2.14) with CHD. The prevalences of GS and multiple organ system CM decreased significantly during the study period. This study was the largest and most comprehensive population-based study to evaluate the association between CHD and ECM in newborns.

Online versus offline spatiotemporal image correlation (STIC) M-mode for the evaluation of cardiac longitudinal annular displacement in fetal growth restriction.

PubMed

Tanis, Jozien C; Mohammed, Nuruddin; Bennasar, Mar; Martinez, Josep Maria; Bijnens, Bart; Crispi, Fatima; Gratacos, Eduard

2018-07-01

Our first aim was to compare online M-mode with offline spatiotemporal image correlation (STIC) M-mode for assessing longitudinal annular displacement (LAD) in growth-restricted fetuses (FGR). Our second aim was to compare LAD measures of FGR cases with controls. Prospective study including 40 FGR cases (defined estimated fetal weight and birth weight <10th centile) and 72 normally grown fetuses matched to cases by gestational age at scan. LAD was measured with online M-mode and offline STIC M-mode at the left and right ventricular free walls and septum in all fetuses. FGR cases had a significant decrease in LAD by STIC in all sites as compared to controls (e.g. right LAD in FGR mean 6.7 mm (SD 1.2) versus controls 7.2 mm (1.2), p = .033). There was a non-significant trend for lower values in FGR when using online M-mode (e.g. right LAD in FGR 6.9 mm (1.5) versus controls 7.4 mm (1.5), p = .084). STIC M-mode seems a better method than online M-mode for detecting subtle changes in myocardial motion. STIC presents more precise results and allows an ideal placement of the M-mode arrow. These results confirm previous data suggesting decreased longitudinal motion in FGR.

Prediction of Coronary Artery Disease Risk Based on Multiple Longitudinal Biomarkers

PubMed Central

Yang, Lili; Yu, Menggang; Gao, Sujuan

2016-01-01

In the last decade, few topics in the area of cardiovascular disease (CVD) research have received as much attention as risk prediction. One of the well documented risk factors for CVD is high blood pressure (BP). Traditional CVD risk prediction models consider BP levels measured at a single time and such models form the basis for current clinical guidelines for CVD prevention. However, in clinical practice, BP levels are often observed and recorded in a longitudinal fashion. Information on BP trajectories can be powerful predictors for CVD events. We consider joint modeling of time to coronary artery disease and individual longitudinal measures of systolic and diastolic BPs in a primary care cohort with up to 20 years of follow-up. We applied novel prediction metrics to assess the predictive performance of joint models. Predictive performances of proposed joint models and other models were assessed via simulations and illustrated using the primary care cohort. PMID:26439685

Meta-Analysis of Effect Sizes Reported at Multiple Time Points Using General Linear Mixed Model.

PubMed

Musekiwa, Alfred; Manda, Samuel O M; Mwambi, Henry G; Chen, Ding-Geng

2016-01-01

Meta-analysis of longitudinal studies combines effect sizes measured at pre-determined time points. The most common approach involves performing separate univariate meta-analyses at individual time points. This simplistic approach ignores dependence between longitudinal effect sizes, which might result in less precise parameter estimates. In this paper, we show how to conduct a meta-analysis of longitudinal effect sizes where we contrast different covariance structures for dependence between effect sizes, both within and between studies. We propose new combinations of covariance structures for the dependence between effect size and utilize a practical example involving meta-analysis of 17 trials comparing postoperative treatments for a type of cancer, where survival is measured at 6, 12, 18 and 24 months post randomization. Although the results from this particular data set show the benefit of accounting for within-study serial correlation between effect sizes, simulations are required to confirm these results.

Mapping longitudinal stream connectivity in the North St. Vrain Creek watershed of Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wohl, Ellen; Rathburn, Sara; Chignell, Stephen

We use reach-scale stream gradient as an indicator of longitudinal connectivity for water, sediment, and organic matter in a mountainous watershed in Colorado. Stream reaches with the highest gradient tend to have narrow valley bottoms with limited storage space and attenuation of downstream fluxes, whereas stream reaches with progressively lower gradients have progressively more storage and greater attenuation. We compared the distribution of stream gradient to stream-reach connectivity rankings that incorporated multiple potential control variables, including lithology, upland vegetation, hydroclimatology, road crossings, and flow diversions. We then assessed connectivity rankings using different weighting schemes against stream gradient and against field-basedmore » understanding of relative connectivity within the watershed. Here, we conclude that stream gradient, which is simple to map using publicly available data and digital elevation models, is the most robust indicator of relative longitudinal connectivity within the river network.« less

Examining Procrastination Across Multiple Goal Stages: A Longitudinal Study of Temporal Motivation Theory

PubMed Central

Steel, Piers; Svartdal, Frode; Thundiyil, Tomas; Brothen, Thomas

2018-01-01

Procrastination is among the most common of motivational failures, putting off despite expecting to be worse off. We examine this dynamic phenomenon in a detailed and realistic longitudinal design (Study 1) as well as in a large correlational data set (N = 7400; Study 2). The results are largely consistent with temporal motivation theory. People’s pacing style reflects a hyperbolic curve, with the steepness of the curve predicted by self-reported procrastination. Procrastination is related to intention-action gaps, but not intentions. Procrastinators are susceptible to proximity of temptation and to the temporal separation between their intention and the planned act; the more distal, the greater the gap. Critical self-regulatory skills in explaining procrastination are attention control, energy regulation and automaticity, accounting for 74% of the variance. Future research using this design is recommended, as it provides an almost ideal blend of realism and detailed longitudinal assessment. PMID:29666590

Examining Procrastination Across Multiple Goal Stages: A Longitudinal Study of Temporal Motivation Theory.

PubMed

Steel, Piers; Svartdal, Frode; Thundiyil, Tomas; Brothen, Thomas

2018-01-01

Procrastination is among the most common of motivational failures, putting off despite expecting to be worse off. We examine this dynamic phenomenon in a detailed and realistic longitudinal design (Study 1) as well as in a large correlational data set ( N = 7400; Study 2). The results are largely consistent with temporal motivation theory. People's pacing style reflects a hyperbolic curve, with the steepness of the curve predicted by self-reported procrastination. Procrastination is related to intention-action gaps, but not intentions. Procrastinators are susceptible to proximity of temptation and to the temporal separation between their intention and the planned act; the more distal, the greater the gap. Critical self-regulatory skills in explaining procrastination are attention control, energy regulation and automaticity, accounting for 74% of the variance. Future research using this design is recommended, as it provides an almost ideal blend of realism and detailed longitudinal assessment.

Mapping longitudinal stream connectivity in the North St. Vrain Creek watershed of Colorado

DOE PAGES

Wohl, Ellen; Rathburn, Sara; Chignell, Stephen; ...

2016-05-06

We use reach-scale stream gradient as an indicator of longitudinal connectivity for water, sediment, and organic matter in a mountainous watershed in Colorado. Stream reaches with the highest gradient tend to have narrow valley bottoms with limited storage space and attenuation of downstream fluxes, whereas stream reaches with progressively lower gradients have progressively more storage and greater attenuation. We compared the distribution of stream gradient to stream-reach connectivity rankings that incorporated multiple potential control variables, including lithology, upland vegetation, hydroclimatology, road crossings, and flow diversions. We then assessed connectivity rankings using different weighting schemes against stream gradient and against field-basedmore » understanding of relative connectivity within the watershed. Here, we conclude that stream gradient, which is simple to map using publicly available data and digital elevation models, is the most robust indicator of relative longitudinal connectivity within the river network.« less

Four-year longitudinal study of mandibular dysfunction in children.

PubMed

Magnusson, T; Egermark-Eriksson, I; Carlsson, G E

1985-04-01

A longitudinal study of clinical signs and subjective symptoms of mandibular dysfunction was performed with a 4-yr interval in 119 children, now 11 and 15 yr old. The results showed that 66% in both age groups had clinical signs while 62 and 66%, respectively, complained of subjective symptoms. In most cases the signs were mild, but 11% of the 11-yr-olds and 17% of the 15-yr-olds had moderate, or, in a few cases, severe signs of dysfunction. Most of the children with subjective symptoms had their symptoms occasionally but 3% in the younger and 11% in the older age group had frequent symptoms from the masticatory system. When comparisons were made with the findings 4 yr earlier, it was noted that the subjective symptoms had increased in frequency in the younger children, while the clinical signs had increased in both groups. These age differences, as well as the prevalence figures recorded longitudinally, agreed well with previous findings in cross-sectional investigations of different age groups.

Pure spinal multiple sclerosis: A possible novel entity within the multiple sclerosis disease spectrum.

PubMed

Schee, Jie Ping; Viswanathan, Shanthi

2018-05-01

We identified five female patients retrospectively with relapsing short-segment partial myelitis whose clinical and paraclinical features were suggestive of cord involvement of multiple sclerosis (MS)-type albeit not rigidly fulfilling the 2017 McDonald criteria. Notably, these patients had not developed any typical MS-like brain lesions despite repeated neuroimaging assessments over years. Comprehensive work-up for differential diagnoses of MS and other causes of transverse myelitis particularly neuromyelitis optica spectrum disorders had been consistently negative on longitudinal follow-up. Thus, we postulate a possible entity of pure spinal MS which may represent a novel forme fruste within the MS disease spectrum.

Serial Cohabitation and the Marital Life Course

ERIC Educational Resources Information Center

Lichter, Daniel T.; Qian, Zhenchao

2008-01-01

Using cohort data from the National Longitudinal Survey of Youth, this paper tracks the experiences of "serial cohabitors." Results indicate that only a minority of cohabiting women (about 15%-20%) were involved in multiple cohabitations. Serial cohabitations were overrepresented among economically disadvantaged groups, especially those with low…

School Contextual Experiences and Longitudinal Changes in Depressive Symptoms from Adolescence to Young Adulthood

ERIC Educational Resources Information Center

Wickrama, Thulitha; Vazsonyi, Alexander T.

2011-01-01

The current study examined the direct and multiplicative influences by adolescent school context experiences (disengagement and maltreatment) and contextual characteristics (school minority concentration and school aggregated family poverty) on changes in depressive symptoms from adolescence to young adulthood. Adolescent experiences with…

LONGITUDINAL EFFECTS OF MULTIPLE POLLUTANTS ON CHILD GROWTH, BLOOD PRESSURE AND COGNITION

EPA Science Inventory

Cognitive deficits and child behavior problems not only impose costs and burdens on children and their families, but also on their school systems. The origins of adult diseases, including elevated blood pressure are in childhood, and environmental controls in childhood may sig...

Interaction between Arsenic Exposure from Drinking Water and Genetic Polymorphisms on Cardiovascular Disease in Bangladesh: A Prospective Case-Cohort Study

PubMed Central

Wu, Fen; Jasmine, Farzana; Kibriya, Muhammad G.; Liu, Mengling; Cheng, Xin; Parvez, Faruque; Islam, Tariqul; Ahmed, Alauddin; Rakibuz-Zaman, Muhammad; Jiang, Jieying; Roy, Shantanu; Paul-Brutus, Rachelle; Slavkovich, Vesna; Islam, Tariqul; Levy, Diane; VanderWeele, Tyler J.; Pierce, Brandon L.; Graziano, Joseph H.; Ahsan, Habibul

2015-01-01

Background: Epidemiologic data on genetic susceptibility to cardiovascular effects of arsenic exposure from drinking water are limited. Objective: We investigated whether the association between well-water arsenic and cardiovascular disease (CVD) differed by 170 single nucleotide polymorphisms (SNPs) in 17 genes related to arsenic metabolism, oxidative stress, inflammation, and endothelial dysfunction. Method: We conducted a prospective case-cohort study nested in the Health Effects of Arsenic Longitudinal Study, with a random subcohort of 1,375 subjects and 447 incident fatal and nonfatal cases of CVD. Well-water arsenic was measured in 2000 at baseline. The CVD cases, 56 of which occurred in the subcohort, included 238 coronary heart disease cases, 165 stroke cases, and 44 deaths due to other CVD identified during follow-up from 2000 to 2012. Results: Of the 170 SNPs tested, multiplicative interactions between well-water arsenic and two SNPs, rs281432 in ICAM1 (padj = 0.0002) and rs3176867 in VCAM1 (padj = 0.035), were significant for CVD after adjustment for multiple testing. Compared with those with GC or CC genotype in rs281432 and lower well-water arsenic, the adjusted hazard ratio (aHR) for CVD was 1.82 (95% CI: 1.31, 2.54) for a 1-SD increase in well-water arsenic combined with the GG genotype, which was greater than expected given aHRs of 1.08 and 0.96 for separate effects of arsenic and the genotype alone, respectively. Similarly, the joint aHR for arsenic and the rs3176867 CC genotype was 1.34 (95% CI: 0.95, 1.87), greater than expected given aHRs for their separate effects of 1.02 and 0.84, respectively. Conclusions: Associations between CVD and arsenic exposure may be modified by genetic variants related to endothelial dysfunction. Citation: Wu F, Jasmine F, Kibriya MG, Liu M, Cheng X, Parvez F, Islam T, Ahmed A, Rakibuz-Zaman M, Jiang J, Roy S, Paul-Brutus R, Slavkovich V, Islam T, Levy D, VanderWeele TJ, Pierce BL, Graziano JH, Ahsan H, Chen Y. 2015. Interaction between arsenic exposure from drinking water and genetic polymorphisms on cardiovascular disease in Bangladesh: a prospective case-cohort study. Environ Health Perspect 123:451–457; http://dx.doi.org/10.1289/ehp.1307883 PMID:25575156

Dizziness and Head Injury

PubMed Central

Barber, H. O.

1965-01-01

Dizziness, whether vague or specifically rotational, is a common sequel to head injury, and is often postural. One hundred and sixty-five patients with this symptom were examined. The simple posture tests employed to detect positional nystagmus are described. This physical finding was present in one-quarter of the entire group, and in nearly one-half of cases of longitudinal fracture of temporal bone. In such cases, it is an objective finding that corresponds precisely to the patient's complaint of vertigo. Transverse fracture of temporal bone destroys the inner ear in both cochlear and vestibular parts. Longitudinal fracture is commoner and causes bleeding from the ear; inner-ear damage is usually minor. In the rare cases where persisting postural vertigo and positional nystagmus are disabling, relief of the symptom may be achieved by vestibular denervation of the affected side. PMID:14285289

Study of spin dynamics and damping on the magnetic nanowire arrays with various nanowire widths

NASA Astrophysics Data System (ADS)

Cho, Jaehun; Fujii, Yuya; Konioshi, Katsunori; Yoon, Jungbum; Kim, Nam-Hui; Jung, Jinyong; Miwa, Shinji; Jung, Myung-Hwa; Suzuki, Yoshishige; You, Chun-Yeol

2016-07-01

We investigate the spin dynamics including Gilbert damping in the ferromagnetic nanowire arrays. We have measured the ferromagnetic resonance of ferromagnetic nanowire arrays using vector-network analyzer ferromagnetic resonance (VNA-FMR) and analyzed the results with the micromagnetic simulations. We find excellent agreement between the experimental VNA-FMR spectra and micromagnetic simulations result for various applied magnetic fields. We find that the same tendency of the demagnetization factor for longitudinal and transverse conditions, Nz (Ny) increases (decreases) as increasing the nanowire width in the micromagnetic simulations while Nx is almost zero value in transverse case. We also find that the Gilbert damping constant increases from 0.018 to 0.051 as the increasing nanowire width for the transverse case, while it is almost constant as 0.021 for the longitudinal case.

Survey of A asymmetries in semi-exclusive electron scattering on 4He and 12C

NASA Astrophysics Data System (ADS)

Protopopescu, D.; Hersman, F. W.; Holtrop, M.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bertozzi, W.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Chen, S.; Cole, P. L.; Coleman, A.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Debruyne, D.; De Sanctis, E.; DeVita, R.; Degtyarenko, P. V.; Dennis, L.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hicks, K.; Hleiqawi, I.; Hu, J.; Hyde-Wright, C. E.; Ingram, W.; Ireland, D.; Ito, M. M.; Jenkins, D.; Joo, K.; Juengst, H. G.; Kelley, J. H.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McLauchlan, S. T.; McNabb, J. W. C.; Mecking, B. A.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Ryckebusch, J.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, B.; CLAS Collaboration

2005-02-01

Single spin azimuthal asymmetries A were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarised electrons incident on 4He and 12C targets in the CLAS detector. A is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state interactions (FSI). Experimental values of A were found to be below 5%, typically |A|⩽3% for data with good statistical precision. Optical model in eikonal approximation (OMEA) and relativistic multiple-scattering Glauber approximation (RMSGA) calculations are shown to be consistent with the measured asymmetries.

[Medial longitudinal fasciculus (MLF) syndrome in a patient with giant cell arteritis].

PubMed

Uenaka, Takeshi; Hamaguchi, Hirotoshi; Sekiguchi, Kenji; Kowa, Hisatomo; Kanda, Fumio; Toda, Tatsushi

2015-01-01

A 76-year-old female was referred to our department because of diplopia for two months and intermittent claudication for five months. She showed medial longitudinal fasciculus (MLF) syndrome. Brain MRI (T2WI) showed multiple infarctions in the right pontine tegmentum and left paramedian midbrain. A biopsy of superficial temporal artery showed the characteristic findings of glanulomatous inflammation indicative of giant cell arteritis. We thought the mechanism of this cerebral infarction as artery to artery embolization or intracranial arteritis. Treatment with oral prednisolone (1 mg/kg/day) improved her limb claudication and normalized serum C-reactive protein level.

Serum carotenoid and tocopherol concentrations and risk of asthma in childhood: a nested case-control study.

PubMed

Hämäläinen, N; Nwaru, B I; Erlund, I; Takkinen, H-M; Ahonen, S; Toppari, J; Ilonen, J; Veijola, R; Knip, M; Kaila, M; Virtanen, S M

2017-03-01

The antioxidant hypothesis regarding the risk of asthma in childhood has resulted in inconsistent findings. Some data indicate that the role of antioxidants in childhood asthma risk may have a critical time window of effect, but only a well-designed longitudinal cohort study can clarify this hypothesis. To study the longitudinal associations between serum carotenoid and tocopherol concentrations during the first 4 years of life and asthma risk by the age of 5 years. Based on a case-control design nested within a Finnish birth cohort, 146 asthma cases were matched to 270 controls on birth time, sex, genetic risk, and birth place. Non-fasting blood samples were collected at the ages of 1, 1.5, 2, 3, and 4 years and serum carotenoids and tocopherols were analysed. Parents reported the presence and age at start of persistent doctor-diagnosed asthma in the child at the age of 5 years. Data analyses were conducted using generalized estimating equations. We did not find strong associations between serum carotenoids and tocopherols and the risk of asthma based on age-specific and longitudinal analyses. Both lower and higher quarters of α-carotene and γ-tocopherol increased the risk of asthma. The current findings do not support the suggestion that the increased prevalence of asthma may be a consequence of decreased intake of antioxidant nutrients. Moreover, we did not confirm any critical time window of impact of antioxidants on asthma risk. Replication of these findings in similar longitudinal settings will strengthen this evidence base. © 2017 John Wiley & Sons Ltd.

How a Young Child Learns How to Take Part in Mealtimes in a Japanese Day-Care Center: A Longitudinal Case Study

ERIC Educational Resources Information Center

Ishiguro, Hiroaki

2016-01-01

This research is a longitudinal, ethnographic study that focuses on mealtimes with one boy from 9 to 78 months of age in a day-care center in Japan. It looks at routine interactions between a child, his nursery teachers, and the environment, which is a shared and mutually available communicative space between participants in collaboration. The aim…

Information Systems in Teacher Preparation Programs: What Can We Learn from a 5-Year Longitudinal Case Study of an Electronic Portfolio Database?

ERIC Educational Resources Information Center

Swan, Gerry

2009-01-01

In 2003, a portfolio system was implemented to manage the data associated with the field experiences in a teacher education program at a research institution in the southeast region of the United States. In this longitudinal study, the implementation trends from usage data extracted from the system are used to discuss the implications for the use…

Losing a Language in Childhood: A Longitudinal Case Study on Language Attrition

ERIC Educational Resources Information Center

Flores, Cristina

2015-01-01

This paper is based upon a longitudinal study of L2 attrition in a bilingual child who grew up in an L2 migration background (Germany) and moved to the country of origin (Portugal) at the age of nine, experiencing a "dominance shift from the L2 to the L1." The study aims to analyze the effects of language loss in L2 German. Data…

Linear mixed-effects modeling approach to FMRI group analysis

PubMed Central

Chen, Gang; Saad, Ziad S.; Britton, Jennifer C.; Pine, Daniel S.; Cox, Robert W.

2013-01-01

Conventional group analysis is usually performed with Student-type t-test, regression, or standard AN(C)OVA in which the variance–covariance matrix is presumed to have a simple structure. Some correction approaches are adopted when assumptions about the covariance structure is violated. However, as experiments are designed with different degrees of sophistication, these traditional methods can become cumbersome, or even be unable to handle the situation at hand. For example, most current FMRI software packages have difficulty analyzing the following scenarios at group level: (1) taking within-subject variability into account when there are effect estimates from multiple runs or sessions; (2) continuous explanatory variables (covariates) modeling in the presence of a within-subject (repeated measures) factor, multiple subject-grouping (between-subjects) factors, or the mixture of both; (3) subject-specific adjustments in covariate modeling; (4) group analysis with estimation of hemodynamic response (HDR) function by multiple basis functions; (5) various cases of missing data in longitudinal studies; and (6) group studies involving family members or twins. Here we present a linear mixed-effects modeling (LME) methodology that extends the conventional group analysis approach to analyze many complicated cases, including the six prototypes delineated above, whose analyses would be otherwise either difficult or unfeasible under traditional frameworks such as AN(C)OVA and general linear model (GLM). In addition, the strength of the LME framework lies in its flexibility to model and estimate the variance–covariance structures for both random effects and residuals. The intraclass correlation (ICC) values can be easily obtained with an LME model with crossed random effects, even at the presence of confounding fixed effects. The simulations of one prototypical scenario indicate that the LME modeling keeps a balance between the control for false positives and the sensitivity for activation detection. The importance of hypothesis formulation is also illustrated in the simulations. Comparisons with alternative group analysis approaches and the limitations of LME are discussed in details. PMID:23376789

Linear mixed-effects modeling approach to FMRI group analysis.

PubMed

Chen, Gang; Saad, Ziad S; Britton, Jennifer C; Pine, Daniel S; Cox, Robert W

2013-06-01

Conventional group analysis is usually performed with Student-type t-test, regression, or standard AN(C)OVA in which the variance-covariance matrix is presumed to have a simple structure. Some correction approaches are adopted when assumptions about the covariance structure is violated. However, as experiments are designed with different degrees of sophistication, these traditional methods can become cumbersome, or even be unable to handle the situation at hand. For example, most current FMRI software packages have difficulty analyzing the following scenarios at group level: (1) taking within-subject variability into account when there are effect estimates from multiple runs or sessions; (2) continuous explanatory variables (covariates) modeling in the presence of a within-subject (repeated measures) factor, multiple subject-grouping (between-subjects) factors, or the mixture of both; (3) subject-specific adjustments in covariate modeling; (4) group analysis with estimation of hemodynamic response (HDR) function by multiple basis functions; (5) various cases of missing data in longitudinal studies; and (6) group studies involving family members or twins. Here we present a linear mixed-effects modeling (LME) methodology that extends the conventional group analysis approach to analyze many complicated cases, including the six prototypes delineated above, whose analyses would be otherwise either difficult or unfeasible under traditional frameworks such as AN(C)OVA and general linear model (GLM). In addition, the strength of the LME framework lies in its flexibility to model and estimate the variance-covariance structures for both random effects and residuals. The intraclass correlation (ICC) values can be easily obtained with an LME model with crossed random effects, even at the presence of confounding fixed effects. The simulations of one prototypical scenario indicate that the LME modeling keeps a balance between the control for false positives and the sensitivity for activation detection. The importance of hypothesis formulation is also illustrated in the simulations. Comparisons with alternative group analysis approaches and the limitations of LME are discussed in details. Published by Elsevier Inc.

Recurrent longitudinal extensive transverse myelitis in a neuro-Behçet syndrome treated with infliximab

PubMed Central

Uygunoğlu, Uğur; Pasha, Maarya; Saip, Sabahattin; Siva, Aksel

2015-01-01

Background Spinal cord involvement is not common, but can be seen in neuro-Behçet's syndrome (NBS). The major site of involvement is the cervical spinal cord with the myelitis-like inflammatory lesions continuing more than two segments, and extending to the brainstem. Case A 30-year-old male patient who has been followed with a diagnosis of Behçet's syndrome admitted to our neurology department clinically and radiologically suggestive of recurrent and extensive longitudinal myelitis. His anti-aquaporine antibody was negative. Because of insufficient effect of azathioprine, cyclophosphamide, and corticosteroids, infliximab was started. His clinical and radiological status is stationary for 3 years under infliximab treatment. Discussion Myelitis such as that occurring in our patient may have a similar presentation like neuromyelitis optica (NMO), which should therefore be included in differential diagnosis. Myelitis observed in both NMO and NBS shows spinal cord lesions longer than three or more vertebrae. Anti-aquaporine antibody must be evaluated in all patients presenting with longitudinal myelitis. Anti-tumor necrosis factor agent infliximab might be an alternative treatment in severe form of NBS such as myelitis. Conclusion In our case, successful treatment of recurrent and extensive longitudinal transverse myelitis in NBS with infliximab was demonstrated. PMID:24673549

Early identification of autism in fragile X syndrome: a review

PubMed Central

McCary, L. M.; Roberts, J. E.

2014-01-01

Fragile X syndrome (FXS) is the leading genetic cause of autism, accounting for approximately 5% of autism cases with as many as 50% of individuals with FXS meeting DSM-IV-TR criteria for autistic disorder. Both FXS and idiopathic autism (IA) are attributed to genetic causes; however, FXS is an identified single gene disorder whereas autism is a complex disorder with multiple potential causes, some of which have been identified. Studies in IA have focused on the prospective longitudinal examination of infant siblings of children with autism as a target group due to their high risk of developing the disorder. We propose that this same model be applied to the study of infants with FXS. There is a lack of research focusing on the early development of autism within FXS and debate in the literature regarding how to best conceptualise this co-morbidity or whether it should be considered a co-morbid condition at all. Studying the emergence and stability of autism in infants with FXS has multiple benefits such as clarifying the underlying mechanisms of the development of autism in FXS and solidifying similarities and differences between co-morbid FXS with autism and IA. Infant research in both IA and FXS are discussed as well as conclusions and implications for practice and future research. PMID:22974167

Quantification of biological aging in young adults

PubMed Central

Belsky, Daniel W.; Caspi, Avshalom; Houts, Renate; Cohen, Harvey J.; Corcoran, David L.; Danese, Andrea; Harrington, HonaLee; Israel, Salomon; Levine, Morgan E.; Schaefer, Jonathan D.; Sugden, Karen; Williams, Ben; Yashin, Anatoli I.; Poulton, Richie; Moffitt, Terrie E.

2015-01-01

Antiaging therapies show promise in model organism research. Translation to humans is needed to address the challenges of an aging global population. Interventions to slow human aging will need to be applied to still-young individuals. However, most human aging research examines older adults, many with chronic disease. As a result, little is known about aging in young humans. We studied aging in 954 young humans, the Dunedin Study birth cohort, tracking multiple biomarkers across three time points spanning their third and fourth decades of life. We developed and validated two methods by which aging can be measured in young adults, one cross-sectional and one longitudinal. Our longitudinal measure allows quantification of the pace of coordinated physiological deterioration across multiple organ systems (e.g., pulmonary, periodontal, cardiovascular, renal, hepatic, and immune function). We applied these methods to assess biological aging in young humans who had not yet developed age-related diseases. Young individuals of the same chronological age varied in their “biological aging” (declining integrity of multiple organ systems). Already, before midlife, individuals who were aging more rapidly were less physically able, showed cognitive decline and brain aging, self-reported worse health, and looked older. Measured biological aging in young adults can be used to identify causes of aging and evaluate rejuvenation therapies. PMID:26150497

Multiple dimensions of spirituality in recovery: a lagged mediational analysis of Alcoholics Anonymous' principal theoretical mechanism of behavior change.

PubMed

Krentzman, Amy R; Cranford, James A; Robinson, Elizabeth A R

2013-01-01

Alcoholics Anonymous (AA) states that recovery is possible through spiritual experiences and spiritual awakenings. Research examining spirituality as a mediator of AA's effect on drinking has been mixed. It is unknown whether such findings are due to variations in the operationalization of key constructs, such as AA and spirituality. To answer these questions, the authors used a longitudinal model to test 2 dimensions of AA as focal predictors and 6 dimensions of spirituality as possible mediators of AA's association with drinking. Data from the first 18 months of a 3-year longitudinal study of 364 alcohol-dependent individuals were analyzed. Structural equation modeling was used to replicate the analyses of Kelly et al. (Alcohol Clin Exp Res. 2011;35:454-463) and to compare AA attendance and AA involvement as focal predictors. Multiple regression analyses were used to determine which spirituality dimensions changed as the result of AA participation. A trimmed, data-driven model was employed to test multiple mediation paths simultaneously. The findings of the Kelly et al. study were replicated. AA involvement was a stronger predictor of drinking outcomes than AA attendance. AA involvement predicted increases in private religious practices, daily spiritual experiences, and forgiveness of others. However, only private religious practices mediated the relationship between AA and drinking.

Trident sign trumps Aquaporin-4-IgG ELISA in diagnostic value in a case of longitudinally extensive transverse myelitis.

PubMed

Jolliffe, Evan A; Keegan, B Mark; Flanagan, Eoin P

2018-04-21

Longitudinally-extensive T2-hyperintense spinal cord lesions (≥3 vertebral segments) are associated with neuromyelitis optical spectrum disorder but occur with other disorders including spinal cord sarcoidosis. When linear dorsal subpial enhancement is accompanied by central cord/canal enhancement the axial post-gadolinium sequences may reveal a "trident" pattern that has previously been shown to be strongly suggestive of spinal cord sarcoidosis. We report a case in which the patient was initially diagnosed with neuromyelitis optical spectrum disorder, but where the "trident" sign ultimately led to the correct diagnosis of spinal cord sarcoidosis. Copyright © 2018. Published by Elsevier B.V.

What Happens to a Nursing Home Chain When Private Equity Takes Over? A Longitudinal Case Study

PubMed Central

Bos, Aline; Harrington, Charlene

2017-01-01

We analyzed what happens to a nursing home chain when private equity takes over, with regard to strategy, financial performance, and resident well-being. We conducted a longitudinal (2000-2012) case study of a large nursing home chain that triangulated qualitative and quantitative data from 5 different data sources. Results show that private equity owners continued and reinforced several strategies that were already put in place before the takeover, including a focus on keeping staffing levels low; the new owners added restructuring, rebranding, and investment strategies such as establishing new companies, where the nursing home chain served as an essential “launch customer.” PMID:29161948

Do Undergraduate Paramedic Students Embrace Case Based Learning Using a Blended Teaching Approach? A 3-Year Review

ERIC Educational Resources Information Center

Williams, Brett

2009-01-01

This paper presents the results of a descriptive longitudinal study which aimed to identify student paramedic perceptions of case based learning used in the clinical curriculum of the Bachelor of Emergency Health (BEH) degree at Monash University, Victoria, Australia. Case based learning and its integration within clinical curriculum is an…

Analysis of Speech Disorders in Acute Pseudobulbar Palsy: a Longitudinal Study of a Patient with Lingual Paralysis.

ERIC Educational Resources Information Center

Leroy-Malherbe, V.; Chevrie-Muller, C.; Rigoard, M. T.; Arabia, C.

1998-01-01

This case report describes the case of a 52-year-old man with bilateral central lingual paralysis following a myocardial infarction. Analysis of speech recordings 15 days and 18 months after the attack were acoustically analyzed. The case demonstrates the usefulness of acoustic analysis to detect slight acoustic differences. (DB)

Multiple Effects of Human Resource Development Interventions

ERIC Educational Resources Information Center

Rowold, Jens

2008-01-01

Purpose: This study aims to explore the simultaneous impact of employees participation in non-technical training, technical training, and coaching on subsequent job performance, job involvement, and job satisfaction. Design/methodology/approach: The present study was based on a sample of German call center employees and on a longitudinal,…

Achievement Goal Profiles and Developments in Effort and Achievement in Upper Elementary School

ERIC Educational Resources Information Center

Hornstra, Lisette; Majoor, Marieke; Peetsma, Thea

2017-01-01

Background: The multiple goal perspective posits that certain combinations of achievement goals are more favourable than others in terms of educational outcomes. Aims: This study aimed to examine longitudinally whether students' achievement goal profiles and transitions between profiles are associated with developments in self-reported and…

The Ecology of Early Reading Development for Children in Poverty

ERIC Educational Resources Information Center

Kainz, Kirsten; Vernon-Feagans, Lynne

2007-01-01

In this study we investigated reading development from kindergarten to third grade for 1,913 economically disadvantaged children from the Early Childhood Longitudinal Study-Kindergarten Cohort. Characteristics of the child, the family, classroom instruction, and school composition were used to model influences from multiple levels of children's…

Parental Behavioural Control and Academic Achievement: Striking the Balance between Control and Involvement

ERIC Educational Resources Information Center

Kramer, Karen Z.

2012-01-01

Using a longitudinal US dataset (N = 6,134) we examine the relationship between parental behavioural control and academic achievement and explore the moderating role of parental involvement and parental warmth. Analyses using multiple hierarchical regression with clustering controls shows that parental behavioural control is negatively associated…

Developmental Precursors of Young School-Age Children's Hostile Attribution Bias

ERIC Educational Resources Information Center

Choe, Daniel Ewon; Lane, Jonathan D.; Grabell, Adam S.; Olson, Sheryl L.

2013-01-01

This prospective longitudinal study provides evidence of preschool-age precursors of hostile attribution bias in young school-age children, a topic that has received little empirical attention. We examined multiple risk domains, including laboratory and observational assessments of children's social-cognition, general cognitive functioning,…

Longitudinal thermal heterogeneity in rivers and refugia for coldwater species: effects of scale and climate change

EPA Science Inventory

Climate-change driven increases in water temperature pose multiple challenges for aquatic organisms. Predictions of climate change impacts to biota typically do not account for fine-grained spatiotemporal patterns of stream networks; yet patches of cooler water within rivers c...

Factors Influencing the Academic Achievement of First-Generation College Students

ERIC Educational Resources Information Center

Strayhorn, Terrell L.

2006-01-01

First-generation college students face a number of unique challenges in college. These obstacles may have a disparate effect on educational outcomes such as academic achievement. This study presents findings from an analysis of the Baccalaureate & Beyond Longitudinal Study using hierarchical multiple regression techniques to measure the influence…

Music Acquisition of Children in Rural Zimbabwe: A Longitudinal Observation.

ERIC Educational Resources Information Center

Kreutzer, Natalie Jones

2001-01-01

This article provides qualitative description of behaviors that bring children to musical competence by age 5 in Nharira Communal Lands in Zimbabwe. Based on observation of three villages comprised of multiple extended family groups, the narrative focuses on area demographics, the community's people, musical influences, musical interactions of…

Examining Individual and Ecological Predictors of the Self-Determination of Students with Disabilities

ERIC Educational Resources Information Center

Shogren, Karrie A.; Wehmeyer, Michael L.; Palmer, Susan B.; Soukup, Jane Helen; Little, Todd D.; Garner, Nancy; Lawrence, Margaret

2007-01-01

This article examines the impact of multiple individual and ecological factors on the self-determination of students with learning disabilities, mild and moderate mental retardation, and other health impairments. Baseline data from a multistate, longitudinal research project evaluating interventions to promote self-determination were examined…

Changes in College Student Health:Implications for Academic Performance

ERIC Educational Resources Information Center

Ruthig, Joelle C.; Marrone, Sonia; Hladkyj, Steve; Robinson-Epp, Nancy

2011-01-01

This study investigated the longitudinal associations of health perceptions and behaviors with subsequent academic performance among college students. Multiple health perceptions and behaviors were assessed for 203 college students both at the beginning and end of an academic year. Students' academic performance was also measured at the end of the…

Perceived Competence and Depressive Symptoms among Adolescents: The Moderating Role of Attributional Style

ERIC Educational Resources Information Center

Kim-Spoon, Jungmeen; Ollendick, Thomas H.; Seligman, Laura D.

2012-01-01

This longitudinal study examined the interactive effects of depressive attributional style and multiple domains of perceived competence on depressive symptoms among 431 adolescents. Our structural equation modeling with latent factor interactions indicated that (1) for girls with a higher depressive attributional style, lower perceived competence…

Latino Adolescents' Academic Success: The Role of Discrimination, Academic Motivation, and Gender

ERIC Educational Resources Information Center

Alfaro, Edna C.; Umana-Taylor, Adriana J.; Gonzales-Backen, Melinda A.; Bamaca, Mayra Y.; Zeiders, Katharine H.

2009-01-01

Guided by the academic resilience perspective, the current longitudinal study examined whether academic motivation mediated the relation between Latino adolescents' (N = 221) experiences with discrimination and their academic success. The potential moderating role of gender was also examined. Using multiple group analysis in structural equation…

Individual Differences in Achievement Goals: A Longitudinal Study of Cognitive, Emotional, and Achievement Outcomes

ERIC Educational Resources Information Center

Daniels, Lia M.; Haynes, Tara L.; Stupnisky, Robert H.; Perry, Raymond P.; Newall, Nancy E.; Pekrun, Reinhard

2008-01-01

Within achievement goal theory debate remains regarding the adaptiveness of certain combinations of goals. Assuming a multiple-goals perspective, we used cluster analysis to classify 1002 undergraduate students according to their mastery and performance-approach goals. Four clusters emerged, representing different goal combinations: high…

Revision Knee Arthroplasty in Patients with Inherited Bleeding Disorders: A Single-Center Experience

PubMed Central

Kotela, Andrzej; Wilk-Frańczuk, Magdalena; Żbikowski, Piotr; Łęgosz, Paweł; Ambroziak, Paweł; Kotela, Ireneusz

2017-01-01

Background The results of total knee arthroplasty (TKA) in patients with inherited bleeding disorders (IBDs) are poorer when compared with those in the general population, with a notably higher risk of complications and higher revision rates. Thus, revision procedures are becoming a growing concern in this group of patients. The aim of this study was to evaluate the results of revision TKA in patients with IBD. Material/Methods A retrospective cohort study with longitudinal assessment of hemophilia patients scheduled for revision TKA between January 2010 and September 2015 was performed. The clinical status of the patients was assessed based on the Knee Society Score, and the Numeric Rating Scale was used to assess knee pain severity and patient satisfaction with the surgery. Radiological examination, post-operative complications, and reinterventions were recorded and analyzed. Results Very good results were obtained in all patients treated for aseptic loosening of the implant. However, inferior results were found in cases with infection. All patients operated on for aseptic loosening required only single-stage TKA, whereas patients with infection underwent multiple interventions. Complications were observed only in cases with infection. Conclusions Our study clearly outlined the differences in results based on failure mode, with far inferior results obtained in cases with infection. Given the lack of data in this area as well as the high specificity of this population, further high-quality studies are needed. PMID:28068306

A longitudinal investigation of work environment stressors on the performance and wellbeing of office workers.

PubMed

Lamb, S; Kwok, K C S

2016-01-01

This study uses a longitudinal within-subjects design to investigate the effects of inadequate Indoor Environmental Quality (IEQ) on work performance and wellbeing in a sample of 114 office workers over a period of 8 months. Participants completed a total of 2261 online surveys measuring perceived thermal comfort, lighting comfort and noise annoyance, measures of work performance, and individual state factors underlying performance and wellbeing. Characterising inadequate aspects of IEQ as environmental stressors, these stress factors can significantly reduce self-reported work performance and objectively measured cognitive performance by between 2.4% and 5.8% in most situations, and by up to 14.8% in rare cases. Environmental stressors act indirectly on work performance by reducing state variables, motivation, tiredness, and distractibility, which support high-functioning work performance. Exposure to environmental stress appears to erode individuals' resilience, or ability to cope with additional task demands. These results indicate that environmental stress reduces not only the cognitive capacity for work, but the rate of work (i.e. by reducing motivation). Increasing the number of individual stress factors is associated with a near linear reduction in work performance indicating that environmental stress factors are additive, not multiplicative. Environmental stressors reduce occupant wellbeing (mood, headaches, and feeling 'off') causing indirect reductions in work performance. Improving IEQ will likely produce small but pervasive increases in productivity. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.