Science.gov

Sample records for longitudinal em cursos

  1. Longitudinal information and radiation damage in EM calorimetry

    SciTech Connect

    Green, D.

    1993-02-05

    The SCC radiation field is higher than that encountered by previous hadron collider detectors. In particular, the electromagnetic (EM) calorimeter compartment sees the highest radiation dose. Since an EM calorimeter also makes the most precise energy measurement, special care must be lavished on this part of a calorimeter. Previous studies have concentrated on Monte Carlo examinations of 2 longitudinal compartments within the EM which can alleviate radiation damage. Recently, it was realized that a ``shower maximum`` detector, such as exists in CDF, also contains information of the conversion point of an electromagnetic shower. As such, it can potentially be used in a fashion analogous to the longitudinal compartments, although it is not designed to be optimized for this role.

  2. Uso de modelos mecânicos em curso informal de astronomia para deficientes visuais. Resgate de uma experiência

    NASA Astrophysics Data System (ADS)

    Tavares, E. T., Jr.; Klafke, J. C.

    2003-08-01

    O presente trabalho propõe-se a resgatar uma experiência que teve lugar no Planetário de São Paulo nos anos 60. Em 1962, o Sr. Acácio, então com 37 anos, deficiente visual desde os 27, passou a assistir às aulas ministradas pelo Prof. Aristóteles Orsini aos integrantes do corpo de servidores do Planetário. O Sr. Acácio era o único deficiente da turma e, embora possuísse conhecimentos básicos e relativamente avançados de matemática, enfrentava dificuldades na compreensão e acompanhamento da exposição, como também em estudos posteriores. Com o intuito de auxiliá-lo na superação desses problemas, o Prof. Orsini solicitou a construção de modelos mecânicos que, através do sentido do tato, permitissem o acompanhamento das aulas e a transposição do modelo para o "constructo" mental. Essa prática mostrou-se tão eficaz que facilitou sobejamente o aprendizado da matéria pelo sujeito. O Sr. Acácio passou a integrar o corpo de professores do Planetário/Escola Municipal de Astrofísica, tendo ficado responsável pelo curso de "Introdução à Astronomia" por vários anos. Além disso, a experiência foi tão bem sucedida que alguns dos modelos tiveram seus elementos constitutivos pintados diferencialmente para serem utilizados em cursos regulares do Planetário, tornando-se parte integrante do conjunto de recursos didáticos da instituição. É pensando nessa eficácia, tanto em seu objetivo original permitir o aprendizado de um deficiente visual quanto no subsidiário recurso didático sistemático da instituição que decidimos resgatar essa experiência. Estribados nela, acreditamos ser extremamente produtivo, em termos educacionais, o aperfeiçoamento dos modelos originais, agora resgatados e restaurados, e a criação de outros que pudessem ser utilizados no ensino dessa ciência a deficientes visuais.

  3. Disciplines and Professors of Astronomy in Undergraduate Physics Teachers Formation Courses in Brazilian Universities. (Spanish Title: Disciplinas y Profesores de Astronomia en los Cursos de Licenciatura en Física en Las Universidades Brasileñas.) Disciplinas e Professores de Astronomia Nos Cursos de Licenciatura em Física das Universidades Brasileiras

    NASA Astrophysics Data System (ADS)

    Roberto, Artur Justiniano, Jr.; Reis, Thiago Henrique; dos Reis Germinaro, Daniel

    2014-12-01

    formación. Aparte de eso, los datos levantados en este trabajo apuntan para un número bajo de afiliados a la SAB (Sociedade Astronômica Brasileira) en los cursos investigados. Se verificó que tener astrónomos en una institución no implica tener una disciplina obligatoria de Astronomía en el curso de licenciatura en Física. Este artigo é o resultado de uma pesquisa sobre a formação básica em Astronomia nos cursos de Licenciatura em Física que fizeram o exame nacional ENADE 2011. O objetivo do trabalho foi identificar se há disciplinas de Astronomia nesses cursos, se ela é obrigatória ou optativa/eletiva, qual a sua carga horária e o período em que é oferecida. Pesquisou-se também a relação entre astrônomos, cursos de Licenciatura em Física e disciplinas de Astronomia. Para realizar essa pesquisa utilizamos os dados do ENADE 2011 e também do censo da Astronomia brasileira. Como resultado, se observa que em apenas 15% dos cursos existe uma disciplina obrigatória de Astronomia e que há uma grande probabilidade de que 85% dos professores de Física formados em 2011 não cursaram nenhuma disciplina de Astronomia durante a graduação. Além disso, os dados levantados nesse trabalho apontam um baixo número de filiados à SAB nos cursos pesquisados. Identifica-se que ter astrônomos na instituição não implica em disciplina obrigatória de Astronomia no curso de Licenciatura em Física.

  4. The Demographics and Education of Emergency Medical Services (EMS) Professionals: A National Longitudinal Investigation.

    PubMed

    Bentley, Melissa A; Shoben, Abigail; Levine, Roger

    2016-12-01

    The objectives of this study were to assess longitudinal and cross-sectional changes in Emergency Medical Technician (EMT)-Basics and Paramedics: (1) demographics, (2) employment characteristics, and (3) initial Emergency Medical Services (EMS) education. These data were collected between 1999 and 2008 employing survey techniques aimed at collecting valid data. A random, stratified sample was utilized to allow results to be generalizable to the nationally certified EMS population. Survey weights that were adjusted for each stratum's response were estimated. Weighted percentages, averages for continuous variables, and 95% confidence intervals (CIs) were calculated. Significant changes over time were noted when the CIs did not overlap. In all 10 years of data collection, the proportion of EMT-Paramedics who were male was greater than the proportion of EMT-Basics who were male. A substantial proportion of respondents performed EMS services for more than one agency: between 39.8% and 43.5% of EMT-Paramedics and 18.4% and 22.4% of EMT-Basic respondents reported this. The most common type of employer for both EMT-Basics and EMT-Paramedics was fire-based organizations. About one-third of EMT-Basics (32.3%-40.1%) and almost one-half of EMT-Paramedics (43.1%-45.3%) reported that these organizations were their main EMS employer. Rural areas (<25,000 residents) were the most common practice settings for EMT-Basics (52.1%-63.7%), while more EMT-Paramedics worked in urban settings (65.2%-77.7%). This analysis serves as a useful baseline to measure future changes in the EMS profession. This study described the demographic and work-life characteristics of a cohort of nationally certified EMT-Basics and Paramedics over a 10-year period. This analysis also summarized initial EMS education changes over time. Bentley MA , Shoben A , Levine R . The demographics and education of Emergency Medical Services (EMS) professionals: a national longitudinal investigation. Prehosp Disaster Med

  5. Essays on Eclipses, Transits and Occultations as Teaching Tools in the Introductory Astronomy College Course. (Spanish Title: Ensayos sobre Eclipses, Tránsitos y Ocultaciones Como Herramientas de Enseñanza en el Curso Universitario Introductorio a la Astronomía.) Ensaios sobre Eclipses, Trânsitos e Ocultações Como Ferramentas de Ensino em um Curso Universitário Introdutório de Astromomia

    NASA Astrophysics Data System (ADS)

    Dcruz, Noella L.

    2014-07-01

    estudiantes que escribieran dos ensayos cortos de tres que se proponían. Los ensayos contenían partes descriptivas y conceptuales. Los mismos estaban destinados a servir como herramientas de enseñanza. 62% de los 106 ensayos de 55 estudiantes obtuvo grados A, B o C. 21% de los 47 encuestados que respondieron al cuestionario posterior consideró que los ensayos aumentaron su interés por la astronomía. 49% de los encuestados consideró que los ensayos no eran educacionalmente útiles y que no deben ser propuestos de nuevo. Las respuestas escritas más comunes a nuestra encuesta indicaran que los estudiantes necesitan más orientación y una mejor preparación en la redacción de ensayos exitosos. Dado que los estudiantes encontraron las piezas conceptuales de los ensayos difíciles, en el futuro vamos a ofrecer actividades pertinentes antes de los plazos de redacción para ayudar a los estudiantes a crear ensayos de mayor calidad. Nós ocasionalmente incluímos projetos em nosso curso universitário introdutório centrado no aluno para permitir aos estudantes que pertencem às carreiras não científicas explorar alguns conceitos astronômicos em mais detalhes do que o normal. Tais projetos também enfatizam eventos astronômicos em curso ou futuros. Esperamos que os alunos se sintam mais interessados na astronomia através de projetos ligados a eventos astronômicos. No termo de Primavera de 2012 (EUA), propomos ensaios curtos focados em eclipses, trânsitos e ocultações para promover o raro trânsito de Vênus que ocorreu no dia 5 de junho de 2012. Pedimos aos alunos que escrevessem dois ensaios curtos dentre três que foram propostos. Os ensaios continham partes descritivas e conceituais. Eles foram feitos para servir como ferramentas de ensino. 62% de 106 ensaios de 55 alunos ganhou graus A, B ou C. 21% dos 47 entrevistados que responderam ao levantamento posterior sentiu que os ensaios aumentaram seu interesse na astronomia. 49% dos inquiridos consideraram que os

  6. The longitudinal study of turnover and the cost of turnover in EMS

    PubMed Central

    Patterson, P. Daniel; Jones, Cheryl B.; Hubble, Michael W.; Carr, Matthew; Weaver, Matthew D.; Engberg, John; Castle, Nicholas

    2010-01-01

    Purpose Few studies have examined employee turnover and associated costs in emergency medical services (EMS). The purpose of this study was to quantify the mean annual rate of turnover, total median cost of turnover, and median cost per termination in a diverse sample of EMS agencies. Methods A convenience sample of 40 EMS agencies was followed over a 6 month period. Internet, telephone, and on-site data collection methods were used to document terminations, new hires, open positions, and costs associated with turnover. The cost associated with turnover was calculated based on a modified version of the Nursing Turnover Cost Calculation Methodology (NTCCM). The NTCCM identified direct and indirect costs through a series of questions that agency administrators answered monthly during the study period. A previously tested measure of turnover to calculate the mean annual rate of turnover was used. All calculations were weighted by the size of the EMS agency roster. The mean annual rate of turnover, total median cost of turnover, and median cost per termination were determined for 3 categories of agency staff mix: all paid staff, mix of paid and volunteer (mixed), and all-volunteer. Results The overall weighted mean annual rate of turnover was 10.7%. This rate varied slightly across agency staffing mix: (all-paid=10.2%, mixed=12.3%, all-volunteer=12.4%). Among agencies that experienced turnover (n=25), the weighted median cost of turnover was $71,613.75, which varied across agency staffing mix: (all-paid=$86,452.05, mixed=$9,766.65, and all-volunteer=$0). The weighted median cost per termination was $6,871.51 and varied across agency staffing mix: (all-paid=$7,161.38, mixed=$1,409.64, and all-volunteer=$0). Conclusions Annual rates of turnover and costs associated with turnover vary widely across types of EMS agencies. The study’s mean annual rate of turnover was lower than expected based on information appearing in the news media and EMS trade magazines. Findings

  7. The Longitudinal Emergency Medical Technician (EMT) Attributes and Demographics Study (LEADS): The First 10 Years and a Look at Public Perception of Emergency Medical Services (EMS).

    PubMed

    Crowe, Remle P; Bentley, Melissa A; Levine, Roger

    2016-12-01

    Crowe RP , Bentley MA , Levine R . The Longitudinal Emergency Medical Technician (EMT) Attributes and Demographics Study (LEADS): the first 10 years and a look at public perception of Emergency Medical Services (EMS). Prehosp Disaster Med. 2016;31(Suppl. 1):s1-s6.

  8. Nonlocal Heat Transport by Longitudinal/Transverse EM Waves in Magnetically Confined Plasmas and Modelling of the Observed Nonlocal Phenomena in a Tokamak

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. B.

    1996-11-01

    The nonlocal transport approach is formulated, based on anomalous cross-field energy transport (ACFET) by the longitudinal/tranverse EM waves of the mean free path of the order and much larger than plasma characteristic size and, correspondingly, on integral equation in space variables. Self-consistency of this approach is shown in interpreting those observed phenomena of nonlocality whose interpretation in "local", diffusion-like approaches gives instant jumps of thermal diffusivities in a large part of plasma volume. The modelling is carried out of the initial stage of recently observed phenomena of fast nonlocal energy transport: (i) net inward flux of energy during off-axis heating (vs. ECRH experiments on D-III-D); (ii) prompt rise of temperature in the core in "cold pulse" experiments (fast cooling of the periphery) on TEXT and TFTR; (iii) fast "volumetric" response of energy transport to plasma edge behavior during L-H transitions (in JET and JT-60U). The results suggest (a) universal and transparent physical explanation of the mechanism of nonlocal inward energy flux, which is lost in diffusion-like approaches, and (b) necessity to append existing numerical codes with nonlocal transport term, an integral in space variables.

  9. Multivariate Longitudinal Analysis with Bivariate Correlation Test.

    PubMed

    Adjakossa, Eric Houngla; Sadissou, Ibrahim; Hounkonnou, Mahouton Norbert; Nuel, Gregory

    2016-01-01

    In the context of multivariate multilevel data analysis, this paper focuses on the multivariate linear mixed-effects model, including all the correlations between the random effects when the dimensional residual terms are assumed uncorrelated. Using the EM algorithm, we suggest more general expressions of the model's parameters estimators. These estimators can be used in the framework of the multivariate longitudinal data analysis as well as in the more general context of the analysis of multivariate multilevel data. By using a likelihood ratio test, we test the significance of the correlations between the random effects of two dependent variables of the model, in order to investigate whether or not it is useful to model these dependent variables jointly. Simulation studies are done to assess both the parameter recovery performance of the EM estimators and the power of the test. Using two empirical data sets which are of longitudinal multivariate type and multivariate multilevel type, respectively, the usefulness of the test is illustrated.

  10. Simultaneous maximum a posteriori longitudinal PET image reconstruction

    NASA Astrophysics Data System (ADS)

    Ellis, Sam; Reader, Andrew J.

    2017-09-01

    Positron emission tomography (PET) is frequently used to monitor functional changes that occur over extended time scales, for example in longitudinal oncology PET protocols that include routine clinical follow-up scans to assess the efficacy of a course of treatment. In these contexts PET datasets are currently reconstructed into images using single-dataset reconstruction methods. Inspired by recently proposed joint PET-MR reconstruction methods, we propose to reconstruct longitudinal datasets simultaneously by using a joint penalty term in order to exploit the high degree of similarity between longitudinal images. We achieved this by penalising voxel-wise differences between pairs of longitudinal PET images in a one-step-late maximum a posteriori (MAP) fashion, resulting in the MAP simultaneous longitudinal reconstruction (SLR) method. The proposed method reduced reconstruction errors and visually improved images relative to standard maximum likelihood expectation-maximisation (ML-EM) in simulated 2D longitudinal brain tumour scans. In reconstructions of split real 3D data with inserted simulated tumours, noise across images reconstructed with MAP-SLR was reduced to levels equivalent to doubling the number of detected counts when using ML-EM. Furthermore, quantification of tumour activities was largely preserved over a variety of longitudinal tumour changes, including changes in size and activity, with larger changes inducing larger biases relative to standard ML-EM reconstructions. Similar improvements were observed for a range of counts levels, demonstrating the robustness of the method when used with a single penalty strength. The results suggest that longitudinal regularisation is a simple but effective method of improving reconstructed PET images without using resolution degrading priors.

  11. Longitudinal impedance of RHIC

    SciTech Connect

    Blaskiewicz, M.; Brennan, J. M.; Mernick, K.

    2015-05-03

    The longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. For the blue RHIC ring Im(Z/n) = 1.5±0.2Ω. For the yellow ring Im(Z/n) = 5.4±1Ω.

  12. Longitudinal Multistage Testing

    ERIC Educational Resources Information Center

    Pohl, Steffi

    2013-01-01

    This article introduces longitudinal multistage testing (lMST), a special form of multistage testing (MST), as a method for adaptive testing in longitudinal large-scale studies. In lMST designs, test forms of different difficulty levels are used, whereas the values on a pretest determine the routing to these test forms. Since lMST allows for…

  13. Longitudinal Stability Calculations

    SciTech Connect

    Blaskiewicz,M.

    2009-01-02

    Coupled bunch longitudinal stability in the presence of high frequency impedances is considered. A frequency domain technique is developed and compared with simulations. The frequency domain technique allows for absolute stability tests and is applied to the problem of longitudinal stability in RHIC with the new 56 MHz RF system.

  14. Solar Physics Topics in High School: Analysis of a Course with Practical Activities at Dietrich Schiel Observatory. (Spanish Title: Temas de Física Solar Para Estudiantes de Escuelas Secundarias: un Análisis de un Curso con Enfoque Práctico en el Observatorio Dietrich Schiel.) Tópicos de Física Solar no Ensino Médio: Análise de um Curso com Atividades Práticas no Observatório Dietrich Schiel

    NASA Astrophysics Data System (ADS)

    Calbo Aroca, Silvia; Donizete Colombo, Pedro, Jr.; Celestino Silva, Cibelle

    2012-12-01

    algunos estudiantes sabían que un espectro puede estar formado por un prisma o red de difracción, la mayor parte de ellos desconocía la naturaleza de las líneas espectrales. A lo largo del curso, esta cuestión fue trabajada con un enfoque práctico mediante la observación del espectro solar y de las lámparas durante clases expositivas/dialogadas. Los resultados obtenidos en el curso mustran la importancia de los centros de ciencia como un apoyo en la educación formal. En este caso en particular, la Sala Solar del Observatorio Dietrich Schiel se destaca como un entorno favorable para la enseñanza de la física moderna en la escuela secundaria. Este trabalho analisa resultados obtidos em um curso sobre física solar para alunos do ensino médio promovido pelo Observatório Dietrich Schiel da USP. O curso foi elaborado pelos autores com a intenção de investigar concepções sobre o Sol, ensinar tópicos de física moderna relacionados ao Sol e conhecimentos gerais sobre o astro rei. A metodologia de coleta de dados consistiu em gravação em áudio e vídeo das aulas e das entrevistas semi-estruturadas, e respostas a questionários escritos. Os resultados mostraram que a maioria dos participantes concebeu o Sol como constituído por fogo e as manchas solares como buracos na superfície solar. Embora alguns alunos soubessem que um espectro pode ser formado por um prisma ou rede de difração, a maior parte deles desconhecia a natureza das linhas espectrais. Ao longo do curso, este tema foi trabalhado com uma abordagem prática com observação do espectro solar e de lâmpadas e em aulas expositivo-dialogadas. Os resultados obtidos no curso apontam para a importância dos centros de ciências como parceiros da educação formal. Neste caso específico, a Sala Solar do Observatório Dietrich Schiel é um ambiente propício para o ensino de física moderna no ensino médio.

  15. Longitudinal Magnification Drawing Mistake

    NASA Astrophysics Data System (ADS)

    Rabal, Héctor; Cap, Nelly; Trivi, Marcelo

    2004-01-01

    Lateral magnification in image formation by positive lenses, mirrors, and dioptrics is usually appropriately developed in most optics textbooks.1-9 However, the image of a three-dimensional object occupies a three-dimensional region of space. The optical system affects both the transverse and the longitudinal dimensions of the object and, in general, does it in different ways. The magnification in the direction of the optical axis (the longitudinal magnification) is seldom treated. In several texts, the concept of longitudinal magnification is not even considered. Symmetrical objects (such as arrows) are used and their images appear laterally inverted. It is not shown how a longitudinally nonsymmetric object is imaged. One of the few books where this subject is well treated is in the textbook by Hecht.10 We have repeatedly verified in our classes that there is some confusion related to this subject. Students tend to believe that the image is longitudinally symmetric with respect to the lens optic center. Some prestigious texts commit the same mistake. In addition, a very nice optics book,11 a catalogue of optical hardware,12 a worldwide scientific magazine,13 a paper in an optics journal,14 and a Spanish encyclopedia,15 for example, have also been found to contain this error in drawing the image of a three-dimensional object formed by a positive lens. In this paper we suggest that the teaching of longitudinal magnification should be done with some care and we include a figure showing a properly drawn image.

  16. Multivariate Longitudinal Analysis with Bivariate Correlation Test

    PubMed Central

    Adjakossa, Eric Houngla; Sadissou, Ibrahim; Hounkonnou, Mahouton Norbert; Nuel, Gregory

    2016-01-01

    In the context of multivariate multilevel data analysis, this paper focuses on the multivariate linear mixed-effects model, including all the correlations between the random effects when the dimensional residual terms are assumed uncorrelated. Using the EM algorithm, we suggest more general expressions of the model’s parameters estimators. These estimators can be used in the framework of the multivariate longitudinal data analysis as well as in the more general context of the analysis of multivariate multilevel data. By using a likelihood ratio test, we test the significance of the correlations between the random effects of two dependent variables of the model, in order to investigate whether or not it is useful to model these dependent variables jointly. Simulation studies are done to assess both the parameter recovery performance of the EM estimators and the power of the test. Using two empirical data sets which are of longitudinal multivariate type and multivariate multilevel type, respectively, the usefulness of the test is illustrated. PMID:27537692

  17. Longitudinal magnetoresistance of potassium

    NASA Astrophysics Data System (ADS)

    Huberman, M. L.

    1987-06-01

    Recently, Zhu and Overhauser showed that the Hall coefficient of potassium is anisotropic, depending on the angle between the applied magnetic field and the charge-density wave. It follows that the Hall coefficient of a polydomain sample is inhomogeneous. By means of effective-medium theory, the magnetoresistance of a domain structure has been evaluated. It is shown that both the longitudinal and transverse magnetoresistance increase with increasing field. The Kohler slope depends on the domain distribution. For a random distribution, the longitudinal and transverse Kohler slopes are about (1/2)% and 1(1/2)%, respectively.

  18. Longitudinal Functional Data Analysis.

    PubMed

    Park, So Young; Staicu, Ana-Maria

    We consider dependent functional data that are correlated because of a longitudinal-based design: each subject is observed at repeated times and at each time a functional observation (curve) is recorded. We propose a novel parsimonious modeling framework for repeatedly observed functional observations that allows to extract low dimensional features. The proposed methodology accounts for the longitudinal design, is designed to study the dynamic behavior of the underlying process, allows prediction of full future trajectory, and is computationally fast. Theoretical properties of this framework are studied and numerical investigations confirm excellent behavior in finite samples. The proposed method is motivated by and applied to a diffusion tensor imaging study of multiple sclerosis.

  19. GATB LONGITUDINAL MATURATION STUDY.

    ERIC Educational Resources Information Center

    DROEGE, ROBERT C.

    THIS ARTICLE DESCRIBES RESULTS OF THE FIRST IN A SERIES OF THREE LARGE-SCALE LONGITUDINAL STUDIES CONDUCTED BY THE U.S. EMPLOYMENT SERVICE TO INCREASE THE USEFULNESS OF THE GENERAL APTITUDE TEST BATTERY (GATB) FOR COUNSELING HIGH SCHOOL STUDENTS. THE FINAL SAMPLE CONSISTED OF 26,708 HIGH SCHOOL STUDENTS. ALL WERE TESTED WITH THE GATB IN 1958, AND…

  20. Longitudinal discharge laser baffles

    DOEpatents

    Warner, B.E.; Ault, E.R.

    1994-06-07

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  1. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, B.E.; Miller, J.L.; Ault, E.R.

    1994-08-23

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window. 2 figs.

  2. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam.

  3. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, Bruce E.; Miller, John L.; Ault, Earl R.

    1994-01-01

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window.

  4. Joint Analysis of Survival Time and Longitudinal Categorical Outcomes

    PubMed Central

    Choi, Jaeun; Cai, Jianwen; Zeng, Donglin; Olshan, Andrew F.

    2013-01-01

    In biomedical or public health research, it is common for both survival time and longitudinal categorical outcomes to be collected for a subject, along with the subject’s characteristics or risk factors. Investigators are often interested in finding important variables for predicting both survival time and longitudinal outcomes which could be correlated within the same subject. Existing approaches for such joint analyses deal with continuous longitudinal outcomes. New statistical methods need to be developed for categorical longitudinal outcomes. We propose to simultaneously model the survival time with a stratified Cox proportional hazards model and the longitudinal categorical outcomes with a generalized linear mixed model. Random effects are introduced to account for the dependence between survival time and longitudinal outcomes due to unobserved factors. The Expectation-Maximization (EM) algorithm is used to derive the point estimates for the model parameters, and the observed information matrix is adopted to estimate their asymptotic variances. Asymptotic properties for our proposed maximum likelihood estimators are established using the theory of empirical processes. The method is demonstrated to perform well in finite samples via simulation studies. We illustrate our approach with data from the Carolina Head and Neck Cancer Study (CHANCE) and compare the results based on our simultaneous analysis and the separately conducted analyses using the generalized linear mixed model and the Cox proportional hazards model. Our proposed method identifies more predictors than by separate analyses. PMID:26052353

  5. Longitudinally graded optical fibers

    NASA Astrophysics Data System (ADS)

    Evert, A.; James, A.; Hawkins, T.; Foy, P.; Dong, L.; Stolen, R.; Ballato, J.; Dragic, P.; Rice, R.

    2013-03-01

    Described herein, for the first time to the best of our knowledge, are results on optical fibers possessing significant compositional gradations along its length due to longitudinal control of the core glass composition. More specifically, MCVD-derived germanosilicate fibers were fabricated that exhibited a gradient of up to about 0.55 weight % GeO2 per meter. These gradients are about 1900 times greater than previously reported fibers possessing longitudinal changes in composition. The refractive index difference is shown to change by about 0.001, representing a numerical aperture change of about 10%, over a fiber length of less than 20 m. The lowest attenuation measured from the present longitudinally-graded fiber (LGF) was 82 dB/km at a wavelength of 1550 nm, though this is shown to result from extrinsic process-induced factors and could be reduced with further optimization. The stimulated Brillouin scattering (SBS) spectrum from the LGF exhibited a 4.4 dB increase in the spectral width, and thus reduction in Brillouin gain, relative to a standard commercial single mode fiber, over a fiber length of only 17 m. The method employed is very straight-forward and provides for a wide variety of longitudinal refractive index and acoustic velocity profiles, as well as core shapes, which could be especially valuable for SBS suppression in high-energy laser systems. Next generation analogs, with longitudinally-graded compositional profiles that are very reasonable to fabricate, are shown computationally to be more effective at suppressing SBS than present alternatives, such as externally-applied temperature or strain gradients.

  6. Experimental Demonstration of Longitudinal Magnification

    ERIC Educational Resources Information Center

    Razpet, Nada; Susman, Katarina; Cepic, Mojca

    2009-01-01

    We describe an experiment which enables the observation of longitudinal magnification for the real image of a three-dimensional (3D) object formed by a converging lens. The experiment also shows the absence of longitudinal inversion. Possible reasons for misconceptions with respect to real images and longitudinal inversions are discussed and a…

  7. Experimental Demonstration of Longitudinal Magnification

    ERIC Educational Resources Information Center

    Razpet, Nada; Susman, Katarina; Cepic, Mojca

    2009-01-01

    We describe an experiment which enables the observation of longitudinal magnification for the real image of a three-dimensional (3D) object formed by a converging lens. The experiment also shows the absence of longitudinal inversion. Possible reasons for misconceptions with respect to real images and longitudinal inversions are discussed and a…

  8. Longitudinally Graded Optical Fibers

    NASA Astrophysics Data System (ADS)

    Evert, Alexander George

    Described herein, for the first time to the best of our knowledge, are optical fibers possessing significant compositional gradations along their length due to longitudinal control of the core glass composition. More specifically, MCVD-derived germanosilicate fibers were fabricated that exhibited a gradient of up to about 0.55 weight percent GeO2 per meter. These gradients are about 1900 times greater than previously reported for fibers possessing longitudinal changes in composition. The refractive index difference is shown to change by about 0.001, representing a numerical aperture change of about 10%, over a fiber length of less than 20 m. The lowest attenuation measured from the present longitudinally-graded fiber (LGF) was 82 dB/km at a wavelength of 1550 nm, though this is shown to result from extrinsic process-induced factors and could be reduced with further optimization. The stimulated Brillouin scattering (SBS) spectrum from the LGF exhibited a 4.4 dB increase in the spectral width, and thus reduction in Brillouin gain, relative to a standard commercial single mode fiber, over a fiber length of only 17 m. Fibers with longitudinally uniform (i.e., not gradient) refractive index profiles but differing chemical compositions among various core layers were also fabricated to determine acoustic effects of the core slug method. The refractive index of the resulting preform varies by about +/- 0.00013 from the average. Upon core drilling, it was found that the core slugs had been drilled off-center from the parent preform, resulting in semi-circular core cross sections that were unable to guide light. As a result, optical analysis could not be conducted. Chemical composition data was obtained, however, and is described herein. A third fiber produced was actively doped with ytterbium (Yb3 ) and fabricated similarly to the previous fibers. The preforms were doped via the solution doping method with a solution of 0.015 M Yb 3 derived from ytterbium chloride

  9. Muon cooling: longitudinal compression.

    PubMed

    Bao, Yu; Antognini, Aldo; Bertl, Wilhelm; Hildebrandt, Malte; Khaw, Kim Siang; Kirch, Klaus; Papa, Angela; Petitjean, Claude; Piegsa, Florian M; Ritt, Stefan; Sedlak, Kamil; Stoykov, Alexey; Taqqu, David

    2014-06-06

    A 10  MeV/c positive muon beam was stopped in helium gas of a few mbar in a magnetic field of 5 T. The muon "swarm" has been efficiently compressed from a length of 16 cm down to a few mm along the magnetic field axis (longitudinal compression) using electrostatic fields. The simulation reproduces the low energy interactions of slow muons in helium gas. Phase space compression occurs on the order of microseconds, compatible with the muon lifetime of 2  μs. This paves the way for the preparation of a high-quality low-energy muon beam, with an increase in phase space density relative to a standard surface muon beam of 10^{7}. The achievable phase space compression by using only the longitudinal stage presented here is of the order of 10^{4}.

  10. Random-effects models for longitudinal data

    SciTech Connect

    Laird, N.M.; Ware, J.H.

    1982-12-01

    Models for the analysis of longitudinal data must recognize the relationship between serial observations on the same unit. Multivariate models with general covariance structure are often difficult to apply to highly unbalanced data, whereas two-stage random-effects models can be used easily. In two-stage models, the probability distributions for the response vectors of different individuals belong to a single family, but some random-effects parameters vary across individuals, with a distribution specified at the second stage. A general family of models is discussed, which includes both growth models and repeated-measures models as special cases. A unified approach to fitting these models, based on a combination of empirical Bayes and maximum likelihood estimation of model parameters and using the EM algorithm, is discussed. Two examples are taken from a current epidemiological study of the health effects of air pollution.

  11. Diseased Region Detection of Longitudinal Knee Magnetic Resonance Imaging Data

    PubMed Central

    Huang, Chao; Shan, Liang; Charles, H. Cecil; Wirth, Wolfgang; Niethammer, Marc; Zhu, Hongtu

    2015-01-01

    Magnetic resonance imaging (MRI) has become an important imaging technique for quantifying the spatial location and magnitude/direction of longitudinal cartilage morphology changes in patients with osteoarthritis (OA). Although several analytical methods, such as subregion-based analysis, have been developed to refine and improve quantitative cartilage analyses, they can be suboptimal due to two major issues: the lack of spatial correspondence across subjects and time and the spatial heterogeneity of cartilage progression across subjects. The aim of this paper is to present a statistical method for longitudinal cartilage quantification in OA patients, while addressing these two issues. The 3D knee image data is preprocessed to establish spatial correspondence across subjects and/or time. Then, a Gaussian hidden Markov model (GHMM) is proposed to deal with the spatial heterogeneity of cartilage progression across both time and OA subjects. To estimate unknown parameters in GHMM, we employ a pseudo-likelihood function and optimize it by using an expectation-maximization (EM) algorithm. The proposed model can effectively detect diseased regions in each OA subject and present a localized analysis of longitudinal cartilage thickness within each latent subpopulation. Our GHMM integrates the strengths of two standard statistical methods including the local subregion-based analysis and the ordered value approach. We use simulation studies and the Pfizer longitudinal knee MRI dataset to evaluate the finite sample performance of GHMM in the quantification of longitudinal cartilage morphology changes. Our results indicate that GHMM significantly outperforms several standard analytical methods. PMID:25823031

  12. A Large, Longitudinal Dune

    NASA Image and Video Library

    2015-02-11

    Taken in late southern spring and when Mars is near perihelion (closest distance to the Sun), this image shows the effects of dry ice sublimation on a longitudinal dune in the far Southern hemisphere. The bright patches on the dune are still covered in frost, and the dark regions are frost-free. Longitudinal dunes form when the wind switches between two common directions*. Based on the direction of this dune's long crest and the orientation of the smaller ripples, it appears the wind blows from the east and from the northwest. However, it would require taking multiple HiRISE images of this location over time and noticing movement before we could say this definitively. The broad base of this dune may indicate that dune sand has spilled out from areas once covered in ice. During the next Martian Southern hemisphere winter (about half a Mars year or one Earth year from when this image was taken), this dune will again be covered in frost and possibly solid carbon dioxide ice, unable to blow in the wind until the volatiles begin to sublimate in the spring. *These are ripples indicating a wind out of the north/northwest. The scene is 250 m across. http://photojournal.jpl.nasa.gov/catalog/PIA19293

  13. Modeling nonstationary longitudinal data.

    PubMed

    Núñez-Antón, V; Zimmerman, D L

    2000-09-01

    An important theme of longitudinal data analysis in the past two decades has been the development and use of explicit parametric models for the data's variance-covariance structure. A variety of these models have been proposed, of which most are second-order stationary. A few are flexible enough to accommodate nonstationarity, i.e., nonconstant variances and/or correlations that are not a function solely of elapsed time between measurements. We review five nonstationary models that we regard as most useful: (1) the unstructured covariance model, (2) unstructured antedependence models, (3) structured antedependence models, (4) autoregressive integrated moving average and similar models, and (5) random coefficients models. We evaluate the relative strengths and limitations of each model, emphasizing when it is inappropriate or unlikely to be useful. We present three examples to illustrate the fitting and comparison of the models and to demonstrate that nonstationary longitudinal data can be modeled effectively and, in some cases, quite parsimoniously. In these examples, the antedependence models generally prove to be superior and the random coefficients models prove to be inferior. We conclude that antedependence models should be given much greater consideration than they have historically received.

  14. A Needs Assessment for a Longitudinal Emergency Medicine Intern Curriculum.

    PubMed

    Shappell, Eric; Ahn, James

    2017-01-01

    A key task of emergency medicine (EM) training programs is to develop a consistent knowledge of core content in recruits with heterogeneous training backgrounds. The traditional model for delivering core content is lecture-based weekly conference; however, a growing body of literature finds this format less effective and less appealing than alternatives. We sought to address this challenge by conducting a needs assessment for a longitudinal intern curriculum for millennial learners. We surveyed all residents from the six EM programs in the greater Chicago area regarding the concept, format, and scope of a longitudinal intern curriculum. We received 153 responses from the 300 residents surveyed (51% response rate). The majority of respondents (80%; 82% of interns) agreed or strongly agreed that a dedicated intern curriculum would add value to residency education. The most positively rated teaching method was simulation sessions (91% positive responses), followed by dedicated weekly conference time (75% positive responses) and dedicated asynchronous resources (71% positive responses). Less than half of respondents (47%; 26% of interns) supported use of textbook readings in the curriculum. There is strong learner interest in a longitudinal intern curriculum. This needs assessment can serve to inform the development of a universal intern curriculum targeting the millennial generation.

  15. A Needs Assessment for a Longitudinal Emergency Medicine Intern Curriculum

    PubMed Central

    Shappell, Eric; Ahn, James

    2017-01-01

    Introduction A key task of emergency medicine (EM) training programs is to develop a consistent knowledge of core content in recruits with heterogeneous training backgrounds. The traditional model for delivering core content is lecture-based weekly conference; however, a growing body of literature finds this format less effective and less appealing than alternatives. We sought to address this challenge by conducting a needs assessment for a longitudinal intern curriculum for millennial learners. Methods We surveyed all residents from the six EM programs in the greater Chicago area regarding the concept, format, and scope of a longitudinal intern curriculum. Results We received 153 responses from the 300 residents surveyed (51% response rate). The majority of respondents (80%; 82% of interns) agreed or strongly agreed that a dedicated intern curriculum would add value to residency education. The most positively rated teaching method was simulation sessions (91% positive responses), followed by dedicated weekly conference time (75% positive responses) and dedicated asynchronous resources (71% positive responses). Less than half of respondents (47%; 26% of interns) supported use of textbook readings in the curriculum. Conclusion There is strong learner interest in a longitudinal intern curriculum. This needs assessment can serve to inform the development of a universal intern curriculum targeting the millennial generation. PMID:28116005

  16. Longitudinal Stern-Gerlach

    NASA Astrophysics Data System (ADS)

    Higinbotham, Douglas

    2006-11-01

    In 1922 Otto Stern and Walther Gerlach split a beam of silver atoms using a transverse gradient field. This experiment, which lead to the understanding that electrons have intrinsic spin, oddly enough does not work for free electrons due to the interplay between the Lorentz force and Heisenberg uncertainly principle. Recent calculations, Phys. Rev. Lett. 79 (1997) 4517 and Phys. Rev. Lett. 86 (2001) 4508, have shown that a dismissed idea of L. Brillouin from 1928 to use a longitudinal gradient field to minimize the effect of the Lorentz force may in fact be possible. The history of the Stern-Gerlach device will be presented along with the revived ideas for separating a beam of free electrons into its two spin states.

  17. Digital Longitudinal Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Rimkus, Daniel Steven

    1985-12-01

    The purpose of this dissertation was to investigate the clinical utility of digital longitudinal tomosynthesis in radiology. By acquiring a finite group of digital images during a longitudinal tomographic exposure, and processing these images, tomographic planes, other than the fulcrum plane, can be reconstructed. This process is now termed "tomosynthesis". A prototype system utilizing this technique was developed. Both phantom and patient studies were done with this system. The phantom studies were evaluated by subjective, visual criterion and by quantitative analysis of edge sharpness and noise in the reconstructions. Two groups of patients and one volunteer were studied. The first patient group consisted of 8 patients undergoing intravenous urography (IVU). These patients had digital tomography and film tomography of the abdomen. The second patient group consisted of 4 patients with lung cancer admitted to the hospital for laser resection of endobronchial tumor. These patients had mediastinal digital tomograms to evaluate the trachea and mainstem bronchi. The knee of one volunteer was imaged by film tomography and digital tomography. The results of the phantom studies showed that the digital reconstructions accurately produced images of the desired planes. The edge sharpness of the reconstructions approached that of the acquired images. Adequate reconstructions were achieved with as few as 5 images acquired during the exposure, with the quality of the reconstructions improving as the number of images acquired increased. The IVU patients' digital studies had less contrast and spatial resolution than the film tomograms. The single renal lesion visible on the film tomograms was also visible in the digital images. The digital mediastinal studies were felt by several radiologists to be superior to a standard chest xray in evaluating the airways. The digital images of the volunteer's knee showed many of the same anatomic features as the film tomogram, but the digital

  18. Longitudinal space charge amplifier

    NASA Astrophysics Data System (ADS)

    Schneidmiller, E. A.; Yurkov, M. V.

    2013-05-01

    Longitudinal space charge (LSC) driven microbunching instability in electron beam formation systems of X-ray FELs is a recently discovered effect hampering beam instrumentation and FEL operation. The instability was observed in different facilities in infrared and visible wavelength ranges. In this paper we propose to use such an instability for generation of vacuum ultraviolet (VUV) and X-ray radiation. A typical longitudinal space charge amplifier (LSCA) consists of few amplification cascades (drift space plus chicane) with a short undulator behind the last cascade. If the amplifier starts up from the shot noise, the amplified density modulation has a wide band, on the order of unity. The bandwidth of the radiation within the central cone is given by inverse number of undulator periods. A wavelength compression could be an attractive option for LSCA since the process is broadband, and a high compression stability is not required. LSCA can be used as a cheap addition to the existing or planned short-wavelength FELs. In particular, it can produce the second color for a pump-probe experiment. It is also possible to generate attosecond pulses in the VUV and X-ray regimes. Some user experiments can profit from a relatively large bandwidth of the radiation, and this is easy to obtain in LSCA scheme. Finally, since the amplification mechanism is broadband and robust, LSCA can be an interesting alternative to self-amplified spontaneous emission free electron laser (SASE FEL) in the case of using laser-plasma accelerators as drivers of light sources.

  19. Current status of longitudinal stability

    NASA Technical Reports Server (NTRS)

    Donlan, Charles J

    1948-01-01

    The problems of static and dynamic longitudinal stability both at high speeds and at low speeds are discussed and data are presented which indicate recent progress made in the solution of these problems.

  20. Registration of Longitudinal Brain Image Sequences with Implicit Template and Spatial-Temporal Heuristics

    PubMed Central

    Wu, Guorong; Wang, Qian; Shen, Dinggang

    2011-01-01

    Accurate measurement of longitudinal changes of brain structures and functions is very important but challenging in many clinical studies. Also, across-subject comparison of longitudinal changes is critical in identifying disease-related changes. In this paper, we propose a novel method to meet these two requirements by simultaneously registering sets of longitudinal image sequences of different subjects to the common space, without assuming any explicit template. Specifically, our goal is to 1) consistently measure the longitudinal changes from a longitudinal image sequence of each subject, and 2) jointly align all image sequences of different subjects to a hidden common space. To achieve these two goals, we first introduce a set of temporal fiber bundles to explore the spatial-temporal behavior of anatomical changes in each longitudinal image sequence. Then, a probabilistic model is built upon the temporal fibers to characterize both spatial smoothness and temporal continuity. Finally, the transformation fields that connect each time-point image of each subject to the common space are simultaneously estimated by the expectation maximization (EM) approach, via the maximum a posterior (MAP) estimation of the probabilistic models. Promising results have been obtained in quantitative measurement of longitudinal brain changes, i.e., hippocampus volume changes, showing better performance than those obtained by either the pairwise or the groupwise only registration methods. PMID:21820065

  1. EMS Student Handbook.

    ERIC Educational Resources Information Center

    Ogle, Patrick

    This student guide is one of a series of self-contained materials for students enrolled in an emergency medical services (EMS) training program. Discussed in the individual sections of the guide are the following topics: the purpose and history of EMS professionals; EMS training, certification and examinations (national and state certification and…

  2. EM International. Volume 1

    SciTech Connect

    Not Available

    1993-07-01

    It is the intent of EM International to describe the Office of Environmental Restoration and Waste Management`s (EM`s) various roles and responsibilities within the international community. Cooperative agreements and programs, descriptions of projects and technologies, and synopses of visits to international sites are all highlighted in this semiannual journal. Focus on EM programs in this issue is on international collaboration in vitrification projects. Technology highlights covers: in situ sealing for contaminated sites; and remote sensors for toxic pollutants. Section on profiles of countries includes: Arctic contamination by the former Soviet Union, and EM activities with Germany--cooperative arrangements.

  3. Longitudinal dynamics in storage rings

    SciTech Connect

    Colton, E.P.

    1986-01-01

    The single-particle equations of motion are derived for charged particles in a storage ring. Longitudinal space charge is included in the potential assuming an infinitely conducting circular beam pipe with a distributed inductance. The framework uses Hamilton's equations with the canonical variables phi and W. The Twiss parameters for longitudinal motion are also defined for the small amplitude synchrotron oscillations. The space-charge Hamiltonian is calculated for both parabolic bunches and ''matched'' bunches. A brief analysis including second-harmonic rf contributions is also given. The final sections supply calculations of dynamical quantities and particle simulations with the space-charge effects neglected.

  4. Longitudinal motion in circular accelerators

    SciTech Connect

    Cole, F.T.

    1985-01-01

    A general description is given of the longitudinal motion of an idealized synchronous particle, exactly in step with the radiofrequency field of a circular accelerator, and a domain in phase and energy, called a bucket, around this particle within which particles are focused around the synchronous particle. This general picture is then made more precise and quantitative. The equations of longitudinal motion and their solutions and the resulting motion are discussed, followed by applications and amplication of the theory. 7 refs., 8 figs. (LEW)

  5. Historia Oral, Experiencias de Aprendizagem e Enraizamento Sociocultural--Um Projeto em Curso (Oral History, Learning Experiences, and Sociocultural Setting--A Project in Process).

    ERIC Educational Resources Information Center

    Vidigal, Luis

    1995-01-01

    Examines education and childhood in Portugal. Uses oral history methods in an educational context, exploring oral statements pedagogically. Considers these statements especially suitable to maintaining aspects of collective memory and social identity, reinforcing students' national and regional identities. Suggests this is very important in…

  6. Historia Oral, Experiencias de Aprendizagem e Enraizamento Sociocultural--Um Projeto em Curso (Oral History, Learning Experiences, and Sociocultural Setting--A Project in Process).

    ERIC Educational Resources Information Center

    Vidigal, Luis

    1995-01-01

    Examines education and childhood in Portugal. Uses oral history methods in an educational context, exploring oral statements pedagogically. Considers these statements especially suitable to maintaining aspects of collective memory and social identity, reinforcing students' national and regional identities. Suggests this is very important in…

  7. Hemorrhagic Longitudinally Extensive Transverse Myelitis.

    PubMed

    Wu, Chris Y; Riangwiwat, Tanawan; Nakamoto, Beau K

    2016-01-01

    Longitudinally extensive transverse myelitis (LETM) may be associated with viral triggers, including both infections and vaccinations. We present a case of a healthy immunocompetent 33-year-old woman who developed a hemorrhagic LETM 2 weeks after seasonal influenza vaccination. Hemorrhagic LETM has not to our knowledge been reported after influenza vaccination. It may represent a forme fruste variant of acute hemorrhagic leukoencephalitis.

  8. Longitudinal Studies of Spelling Development.

    ERIC Educational Resources Information Center

    Ellis, Nick

    Noting that proposed models of literacy development suggest that reading and writing mutually influence and grow from each other, this paper summarizes aspects of stage theories of literacy development and an integrative model, and considers how the model fared in empirical longitudinal tests. The paper begins with a summary of the modal aspects…

  9. Students dance longitudinal standing waves

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.

    2017-05-01

    A demonstration is presented that involves students dancing longitudinal standing waves. The resulting kinaesthetic experience and visualization both contribute towards an understanding of the natural modes of vibrations in open and closed pipes. A video of this fun classroom activity is provided (http://mjtruiz.com/ped/dance/).

  10. Regression Splines with Longitudinal Data

    USDA-ARS?s Scientific Manuscript database

    In many clinical trial studies, patients are observed and/or measured on multiple occasions. To account for the longitudinal nature of the data, a mixed model analysis implemented using SAS PROC MIXED is commonly used. It is typical to make comparisons between dose or treatment groups, possibly cont...

  11. Concepciones Alternativas de "Fotosintesis" en estudiantes Universitarios del curso basico de Biologia y posibles correcciones con el Modelo Educativo MODEF

    NASA Astrophysics Data System (ADS)

    De Jesus Roman, Sandra

    Concepciones Alternativas de Fotosíntesis en estudiantes Universitariosdel curso básico de Biología y posibles correcciones con el Modelo Educativo MODEF El modelo educativo para la enseñanza de Fotosíntesis (MODEF) se implantó para trabajar el problema de las concepciones alternativas (CA) en un curso de Biología General. Se evaluaron los resultados en cuanto al logro del aprendizaje significativo. La pregunta central de la investigación fue: ¿Cómo aporta el modelo educativo en la didáctica y comprensión del tema de fotosíntesis? Se efectuó una investigación acción con una fase cuantitativa y una cualitativa. Para la fase cuantitativa se elaboró una prueba para determinar las concepciones alternativas, se validó y se sometió a los estudiantes que participaron en el estudio antes y después de ofrecer la unidad de metabolismo celular. Los participantes eran estudiantes de primer año de la Universidad de Puerto Rico en Bayamón (UPRB). Se llevó a cabo un análisis de consistencia interna de la prueba mediante el método Alfa de Cronbach. Se analizaron las contestaciones a cada pregunta mediante la prueba de Ji cuadrado de contingencia, se efectuó la prueba de t y el coeficiente r de Pearson. La fase cualitativa incluyó la observación participativa de la investigadora- profesora, las reflexiones de los estudiantes y la información de las entrevistas semi-estructuradas que se realizaron a tres estudiantes del curso. El análisis se llevó a cabo mediante el Modelo de Wolcott. Se trabajaron diez CA de las cuales siete fueron corregidas mediante el Modelo MODEF. Las actividades más importantes para el proceso de aprendizaje incluyeron el trabajo de investigación o búsqueda de información para hacer una presentación digital, la elaboración de tablas, los mapas de conceptos, el uso de visuales o videos y las analogías para explicar conceptos o procesos. En conclusión: se recomienda el uso del Modelo MODEF para la discusión del tema de

  12. Joint partially linear model for longitudinal data with informative drop-outs.

    PubMed

    Kim, Sehee; Zeng, Donglin; Taylor, Jeremy M G

    2017-03-01

    In biomedical research, a steep rise or decline in longitudinal biomarkers may indicate latent disease progression, which may subsequently cause patients to drop out of the study. Ignoring the informative drop-out can cause bias in estimation of the longitudinal model. In such cases, a full parametric specification may be insufficient to capture the complicated pattern of the longitudinal biomarkers. For these types of longitudinal data with the issue of informative drop-outs, we develop a joint partially linear model, with an aim to find the trajectory of the longitudinal biomarker. Specifically, an arbitrary function of time along with linear fixed and random covariate effects is proposed in the model for the biomarker, while a flexible semiparametric transformation model is used to describe the drop-out mechanism. Advantages of this semiparametric joint modeling approach are the following: 1) it provides an easier interpretation, compared to standard nonparametric regression models, and 2) it is a natural way to control for common (observable and unobservable) prognostic factors that may affect both the longitudinal trajectory and the drop-out process. We describe a sieve maximum likelihood estimation procedure using the EM algorithm, where the Akaike information criterion (AIC) and Bayesian information criterion (BIC) are considered to select the number of knots. We show that the proposed estimators achieve desirable asymptotic properties through empirical process theory. The proposed methods are evaluated by simulation studies and applied to prostate cancer data.

  13. Leveraging EMS and VPP

    DTIC Science & Technology

    2009-05-01

    Elements of EMS  International Standards Organization ( ISO ) 14001 , Environmental Management Systems  The Key Elements of EMS: - Policy - Planning...wingman-- ON and OFF duty Fully Conforming vs. Fully Implemented  “Fully Conforming”  Meets standards established in ISO 14001  ESOH council...e n c e Every airman looking out for his wingman-- ON and OFF duty EMS & VPP Commonalities Environmental Management System ISO 14001 : 2004 Voluntary

  14. Eosinophilia-myalgia syndrome: selective cognitive impairment, longitudinal effects, and neuroimaging findings

    PubMed Central

    Armstrong, C.; Lewis, T.; D'Esposito, M.; Freundlich, B.

    1997-01-01

    OBJECTIVE—To identify the specific nature of the neurocognitive impairments of eosinophilia-myalgia syndrome (EMS) in an unselected population, and to present longitudinal patterns.
METHODS—A consecutive sample of 23 patients with EMS and 18 age and education matched control subjects were assessed on a comprehensive neuropsycho- logical battery. Longitudinal results were gathered from six patients.
RESULTS—Neurocognitive impairments were found which represent a subset of deficits reported in previous group and case study reports. Deficits were limited to complex visual memory, conceptual set shifting, and attention, which suggest a selective dysexecutive syndrome. The motor slowing and verbal memory deficits previously reported were not found. Although depression, fatigue, sleep deprivation, and pain were significant symptoms, they were unassociated with deficits with the exception of an association of depression with one deficit. There was no pattern of overall decline over time in a subset of the group, although considerable heterogeneity in the longitudinal patterns of neurocognitive tests was found. Abnormalities of white matter appeared in the MRI of eight of 12patients.
CONCLUSIONS—The neurocognitive and neuroimaging findings contribute to the evidence which indicates that the neural substrate of EMS is white matter damage.

 PMID:9408106

  15. 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

  16. ANÁLISE DA INSERÇÃO DOS TEMAS DE HUMANIDADES E ÉTICA, COM METODOLOGIA DE APRENDIZAGEM BASEADA EM PROBLEMAS, EM CURRICULO MÉDICO INTEGRADO EM ESCOLA PÚBLICA NO DISTRITO FEDERAL, BRASIL

    PubMed Central

    Novaes, Maria Rita Carvalho Garbi; Novaes, Luiz Carlos Garcez; Guilhem, Dirce; Lolas, Fernando; Silveira, Carla; Guiotti, Murilo

    2009-01-01

    Objetivo Realizar uma análise da inserção da ética e humanidades no currículo do Curso de Medicina da Escola Superior em Ciências da Saúde - ESCS, escola pública do Distrito Federal, Brasil, de forma a contribuir com o processo de gestão curricular. Metodologia O Estudo é de coorte e documental. Foram pesquisados 37 termos relacionados à ética e 36 referentes à humanização nos objetivos educacionais e conteúdo dos módulos temáticos, habilidades e atitudes e interação ensino-serviço-comunidade, de 1a a 4a série e no programa do internato no currículo (ano 2006) e no projeto pedagógico do Curso de Medicina (2001). Resultados Maior inserção da humanização, ética e bioética na 1a e 2a série, quando comparado à inserção na 3a e 4a série e no internato, (IC95%-α=0,034, pvalue=0,007). Unidade de habilidades e atitudes: freqüência das 3 temáticas no currículo da 1a a 4a séries (IC95%-α=0,026, pvalue=0,013). Quando comparada a inserção entre o internato e as quatro primeiras séries, observa-se que nestas a inserção da temática humanização é superior (IC95%-α=0,042, pvalue=0,029). Conclusão O currículo desenvolvido no ano de 2006 na ESCS apresentou correlação com o projeto pedagógico do curso e contemplou a temática de forma abrangente, em todas as séries e internato. PMID:20396594

  17. LONGITUDINAL LASER WIRE AT SNS

    SciTech Connect

    Aleksandrov, Alexander V; Liu, Yun; Zhukov, Alexander P

    2014-01-01

    This paper describes a longitudinal H- beam profile scanner that utilizes laser light to detach convoy electrons and an MCP to collect and measure these electrons. The scanner is located in MEBT with H- energy of 2.5MeV and an RF frequency 402.5MHz. The picosecond pulsed laser runs at 80.5MHz in sync with the accelerator RF. The laser beam is delivered to the beam line through a 30m optical fiber. The pulse width after the fiber transmission measures about 10ps. Scanning the laser phase effectively allows measurements to move along ion bunch longitudinal position. We are able to reliably measure production beam bunch length with this method. The biggest problem we have encountered is background signal from electrons being stripped by vacuum. Several techniques of signal detection are discussed.

  18. The Importance of Longitudinal Studies

    NASA Astrophysics Data System (ADS)

    Knezek, Patricia

    2014-01-01

    It has been eight years since the AAS Council unanimously endorsed the document, known as "Equity Now: The Pasadena Recommendations for Gender Equality in Astronomy," in January 2005. This document was the main product of the conference entitled “Women in Astronomy II: Ten Years After” (WIA II), held in June 2003 in Pasadena, CA. One of the key recommendations represented in that document was the need for a longitudinal study of astronomers. It was recognized that in order to understand our own field, how it is evolving, and the impact on individuals, we need to track people over time. I will discuss the fundamental questions that led to the recommendation, and set the stage for the current (ongoing) longitudinal study.

  19. Longitudinal normals for piezoelectric elastic media

    NASA Astrophysics Data System (ADS)

    Duda, A.; Paszkiewicz, T.; Wolski, S.

    2006-02-01

    We show that the problem of finding components of longitudinal normals for all piezoelectric classes is equivalent to the problem of solving two sets of two polynomial equations up to 6th degree. It is proved that the number of longitudinal normals for triclinic media cannot exceed 36. If the number of longitudinal normals contained in any plane is finite, then it cannot be larger than 6. Directions of longitudinal normals are found for quartz, LiGaO2, and Ba2NaNb5O15. For these compounds we numerically studied how piezoelectric terms of the propagation matrix influence the number and directions of the longitudinal normals.

  20. Hemorrhagic Longitudinally Extensive Transverse Myelitis

    PubMed Central

    Wu, Chris Y.; Riangwiwat, Tanawan

    2016-01-01

    Longitudinally extensive transverse myelitis (LETM) may be associated with viral triggers, including both infections and vaccinations. We present a case of a healthy immunocompetent 33-year-old woman who developed a hemorrhagic LETM 2 weeks after seasonal influenza vaccination. Hemorrhagic LETM has not to our knowledge been reported after influenza vaccination. It may represent a forme fruste variant of acute hemorrhagic leukoencephalitis. PMID:27847660

  1. Longitudinal bulk acoustic mass sensor

    NASA Astrophysics Data System (ADS)

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10-15 g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  2. Longitudinal bulk acoustic mass sensor

    SciTech Connect

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-20

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  3. Parameterized Linear Longitudinal Airship Model

    NASA Technical Reports Server (NTRS)

    Kulczycki, Eric; Elfes, Alberto; Bayard, David; Quadrelli, Marco; Johnson, Joseph

    2010-01-01

    A parameterized linear mathematical model of the longitudinal dynamics of an airship is undergoing development. This model is intended to be used in designing control systems for future airships that would operate in the atmospheres of Earth and remote planets. Heretofore, the development of linearized models of the longitudinal dynamics of airships has been costly in that it has been necessary to perform extensive flight testing and to use system-identification techniques to construct models that fit the flight-test data. The present model is a generic one that can be relatively easily specialized to approximate the dynamics of specific airships at specific operating points, without need for further system identification, and with significantly less flight testing. The approach taken in the present development is to merge the linearized dynamical equations of an airship with techniques for estimation of aircraft stability derivatives, and to thereby make it possible to construct a linearized dynamical model of the longitudinal dynamics of a specific airship from geometric and aerodynamic data pertaining to that airship. (It is also planned to develop a model of the lateral dynamics by use of the same methods.) All of the aerodynamic data needed to construct the model of a specific airship can be obtained from wind-tunnel testing and computational fluid dynamics

  4. EMS in the pueblos.

    PubMed

    Vigil, M A

    1994-02-01

    Imagine creating a movie by excerpting scenes from "Dances With Wolves," splicing it with footage from "Code 3" or "Emergency Response" and then flavoring the script with the mystery of a Tony Hillerman novel. A film producer would probably find it quite difficult to choreograph a finished product from such a compilation of material. To hundreds of Native American EMS providers, however, such a movie is played out every day in Indian country. And with this movie come some real-life problems, including trauma, which is the number-one cause of premature death among Native Americans. But a high trauma rate is just one of the challenges facing tribal EMS responders. There's also prolonged response and transport, the problems involved in maintaining the unique culture and standard of care, the challenges of tribal EMS administration and EMS education of Native American students, and the unsure future of Native American EMS. Beyond that, there's the fact that EMS is a s unique to each Indian reservation as are the cultures of the native peoples who reside on these lands. Yet while no two systems are alike, most tribal EMS providers face similar challenges.

  5. Longitudinal Pulmonary Function in Newly Hired, Non-World Trade Center-Exposed Fire Department City of New York Firefighters

    PubMed Central

    Ye, Fen; Hall, Charles B.; Webber, Mayris P.; Cohen, Hillel W.; Dinkels, Michael; Cosenza, Kaitlyn; Weiden, Michael D.; Nolan, Anna; Christodoulou, Vasilios; Kelly, Kerry J.; Prezant, David J.

    2013-01-01

    Background: Few longitudinal studies characterize firefighters’ pulmonary function. We sought to determine whether firefighters have excessive FEV1 decline rates compared with control subjects. Methods: We examined serial measurements of FEV1 from about 6 months prehire to about 5 years posthire in newly hired male, never smoking, non-Hispanic black and white firefighters, hired between 2003 and 2006, without prior respiratory disease or World Trade Center exposure. Similarly defined Emergency Medical Service (EMS) workers served as control subjects. Results: Through June 30, 2011, 940 firefighters (82%) and 97 EMS workers (72%) who met study criteria had four or more acceptable posthire spirometries. Prehire FEV1% averaged higher for firefighters than EMS workers (99% vs 95%), reflecting more stringent job entry criteria. FEV1 (adjusted for baseline age and height) declined by an average of 45 mL/y both for firefighters and EMS workers, with Fire − EMS decline rate differences averaging 0.2 mL/y (CI, −9.2 to 9.6). Four percent of each group had FEV1 less than the lower limit of normal before hire, increasing to 7% for firefighters and 17.5% for EMS workers, but similar percentages of both groups had adjusted FEV1 decline rates ≥ 10%. Mixed effects modeling showed a significant influence of weight gain but not baseline weight: FEV1 declined by about 8 mL/kg gained for both groups. Adjusting for weight change, FEV1 decline averaged 38 mL/y for firefighters and 34 mL/y for EMS workers. Conclusions: During the first 5 years of duty, firefighters do not show greater longitudinal FEV1 decline than EMS control subjects, and fewer of them develop abnormal lung function. Weight gain is associated with a small loss of lung function, of questionable clinical relevance in this fit and active population. PMID:23188136

  6. Longitudinal Control of Intense Charged Particle Beams

    DTIC Science & Technology

    2011-01-01

    contained using longitudinal focusing, I have shown that errors in the applied focusing fields induce space-charge waves at the bunch edges that...profile along the bunch length. When the bunch is contained using longitudinal focusing, I have shown that errors in the applied focusing fields ...90 5.1.1 Beam Expansion without Longitudinal Containment................................ 90 5.1.2 Application of Focusing Fields

  7. Longitudinal study of fingerprint recognition.

    PubMed

    Yoon, Soweon; Jain, Anil K

    2015-07-14

    Human identification by fingerprints is based on the fundamental premise that ridge patterns from distinct fingers are different (uniqueness) and a fingerprint pattern does not change over time (persistence). Although the uniqueness of fingerprints has been investigated by developing statistical models to estimate the probability of error in comparing two random samples of fingerprints, the persistence of fingerprints has remained a general belief based on only a few case studies. In this study, fingerprint match (similarity) scores are analyzed by multilevel statistical models with covariates such as time interval between two fingerprints in comparison, subject's age, and fingerprint image quality. Longitudinal fingerprint records of 15,597 subjects are sampled from an operational fingerprint database such that each individual has at least five 10-print records over a minimum time span of 5 y. In regard to the persistence of fingerprints, the longitudinal analysis on a single (right index) finger demonstrates that (i) genuine match scores tend to significantly decrease when time interval between two fingerprints in comparison increases, whereas the change in impostor match scores is negligible; and (ii) fingerprint recognition accuracy at operational settings, nevertheless, tends to be stable as the time interval increases up to 12 y, the maximum time span in the dataset. However, the uncertainty of temporal stability of fingerprint recognition accuracy becomes substantially large if either of the two fingerprints being compared is of poor quality. The conclusions drawn from 10-finger fusion analysis coincide with the conclusions from single-finger analysis.

  8. Longitudinal study of fingerprint recognition

    PubMed Central

    Yoon, Soweon; Jain, Anil K.

    2015-01-01

    Human identification by fingerprints is based on the fundamental premise that ridge patterns from distinct fingers are different (uniqueness) and a fingerprint pattern does not change over time (persistence). Although the uniqueness of fingerprints has been investigated by developing statistical models to estimate the probability of error in comparing two random samples of fingerprints, the persistence of fingerprints has remained a general belief based on only a few case studies. In this study, fingerprint match (similarity) scores are analyzed by multilevel statistical models with covariates such as time interval between two fingerprints in comparison, subject’s age, and fingerprint image quality. Longitudinal fingerprint records of 15,597 subjects are sampled from an operational fingerprint database such that each individual has at least five 10-print records over a minimum time span of 5 y. In regard to the persistence of fingerprints, the longitudinal analysis on a single (right index) finger demonstrates that (i) genuine match scores tend to significantly decrease when time interval between two fingerprints in comparison increases, whereas the change in impostor match scores is negligible; and (ii) fingerprint recognition accuracy at operational settings, nevertheless, tends to be stable as the time interval increases up to 12 y, the maximum time span in the dataset. However, the uncertainty of temporal stability of fingerprint recognition accuracy becomes substantially large if either of the two fingerprints being compared is of poor quality. The conclusions drawn from 10-finger fusion analysis coincide with the conclusions from single-finger analysis. PMID:26124106

  9. The methodology of the Australian Prehospital Outcomes Study of Longitudinal Epidemiology (APOStLE) Project.

    PubMed

    Cone, David C; Irvine, Katrina A; Middleton, Paul M

    2012-01-01

    This paper describes the methodology of a large emergency medical services (EMS) data linkage research project currently under way in the statewide EMS system of New South Wales, Australia. The paper is intended to provide the reader with an understanding of how linkage techniques can be used to facilitate EMS research. This project, the Australian Prehospital Outcomes Study of Longitudinal Epidemiology (APOStLE) Project, links data from six statewide sources (computer-assisted dispatch, EMS patient health care reports, emergency department data, inpatient data, and two death registries) to enable researchers to examine the patient's entire journey through the health care system, from the emergency 0-0-0 call to the emergency department and inpatient setting, through to discharge or death, for approximately 2.6 million patients transported by the Ambulance Service of New South Wales to emergency departments between June 2006 and July 2009. Manual, deterministic, and probabilistic data linkages are described, and potential applications of linked data in EMS research are outlined.

  10. Modelo de accesibilidad de conceptos matematicos aplicados en el curso de Astronomia Descriptiva para estudiantes con impedimentos visuales en la UPR

    NASA Astrophysics Data System (ADS)

    Isidro Villamizar, Gloria Maria

    Este estudio utiliza metodologia de investigacion cualitativa, con el proposito de describir, analizar y evaluar los procesos de diseno y desarrollo de un modelo de accesibilidad que consiste en estrategias de ensenanza de las matematicas para estudiantes con impedimentos visuales matriculados en el curso de Astronomia Descriptiva en la UPR. Se utilizaron las siguientes estrategias para recopilar la informacion, 1) reflexiones de la investigadora en el proceso de diseno y desarrollo de las lecciones adaptadas, que se registraron en un diario reflexivo. 2) entrevista semiestructurada luego de haber trabajado las lecciones de aprendizaje adaptadas con los participantes. 3) observaciones y notas de la investigadora del trabajo de los participantes. Para obtener la informacion de los participantes se obtuvo los permisos institucionales necesarios; se seleccionaron los participantes y se validaron los instrumentos; se realizo el desarrollo de las lecciones adaptadas con los participantes; y finalmente, se analizo la informacion obtenida. El diseno de las lecciones de aprendizaje adaptadas se hizo siguiendo las recomendaciones curriculares de los temas de matematicas aplicados en el curso de Astronomia Descriptiva realizado por la investigadora durante su semestre de internado. El testimonio de las voces de los participantes se obtuvo del proceso de desarrollo de las lecciones de aprendizaje adaptadas de temas seleccionados de conceptos matematicos requeridos en el curso de Astronomia Descriptiva y de la entrevista semiestructurada con los participantes, luego de haber trabajado las lecciones de aprendizaje. Para el desarrollo de las lecciones de aprendizaje, se utilizaron materiales tactiles adaptados, materiales tactiles disenados y materiales disponibles comercialmente. Los textos de las lecciones se imprimieron en tinta y en Braille. Se exhorta a disenar y desarrollar estrategias de ensenanza accesibles, considerando como recursos para evaluar su efectividad a

  11. Comprension de los conceptos de los enlaces ionico y covalente en estudiantes universitarios del primer curso de quimica general

    NASA Astrophysics Data System (ADS)

    Ballesteros Benavides, Maria Elvira

    Para este trabajo utilizamos el estudio de casos cualitativo que se llevo a cabo en una universidad privada de Puerto Rico. Empleamos como unidad de analisis el concepto de enlace quimico, ionico y covalente. Los participantes fueron los estudiantes de la seccion nocturna del curso de Quimica General I. La investigacion se desarrollo por medio de dos entrevistas de persona a persona, observaciones de las expresiones no verbales y la hoja de identificacion de conceptos. Para la triangulacion tomamos en consideracion las preconcepciones erroneas, las concepciones alternativas y el mapa de conceptos de cada participante. Preparamos un mapa de conceptos para el enlace quimico validado por un comite de expertos. Tambien, elaboramos los mapas de conceptos de los participantes que sirvieron para varios propositos: conocer la estructura conceptual, expresar los logros, hacer comparaciones e identificar la presencia de concepciones alternativas. Entre los hallazgos encontramos que todos los participantes poseen conocimiento previo de los enlaces quimicos ionico y covalente y dentro de ese conocimiento existen preconcepciones erroneas mas numerosas para el enlace ionico. Al principio del semestre el 50% de los participantes demostraron tener "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente. Al finalizar el semestre encontramos en el 40% de los participantes concepciones alternativas tanto para el enlace ionico como para el covalente y el 90% no lograron distinguir un enlace del otro. Nuestras conclusiones fueron que los participantes sin distincion del aprovechamiento academico demostraron tener la tendencia de "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente, presentaron dificultad al integrar los conceptos de los enlaces quimicos ionico y covalente que se pusieron de manifiesto al dar los ejemplos. Las preconcepciones erroneas contribuyen en el desarrollo de las concepciones alternativas. Ademas, los

  12. A Model Longitudinal Observation Medicine Curriculum for an Emergency Medicine Residency.

    PubMed

    Wheatley, Matthew; Baugh, Christopher; Osborne, Anwar; Clark, Carol; Shayne, Philip; Ross, Michael

    2016-04-01

    The role of observation services for emergency department patients has increased in recent years. Driven by changing health care practices and evolving payer policies, many hospitals in the United States currently have or are developing an observation unit (OU) and emergency physicians are most often expected to manage patients in this setting. Yet, few residency programs dedicate a portion of their clinical curriculum to observation medicine. This knowledge set should be integrated into the core training curriculum of emergency physicians. Presented here is a model observation medicine longitudinal training curriculum, which can be integrated into an emergency medicine (EM) residency. It was developed by a consensus of content experts representing the observation medicine interest group and observation medicine section, respectively, from EM's two major specialty societies: the Society for Academic Emergency Medicine (SAEM) and the American College of Emergency Physicians (ACEP). The curriculum consists of didactic, clinical, and self-directed elements. It is longitudinal, with learning objectives for each year of training, focusing initially on the basic principles of observation medicine and appropriate observation patient selection; moving to the management of various observation appropriate conditions; and then incorporating further concepts of OU management, billing, and administration. This curriculum is flexible and designed to be used in both academic and community EM training programs within the United States. Additionally, scholarly opportunities, such as elective rotations and fellowship training, are explored.

  13. Transverse-longitudinal integrated resonator

    DOEpatents

    Hutchinson, Donald P [Knoxville, TN; Simpson, Marcus L [Knoxville, TN; Simpson, John T [Knoxville, TN

    2003-03-11

    A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.

  14. Modeling a Longitudinal Relational Research Data Systems

    ERIC Educational Resources Information Center

    Olsen, Michelle D. Hunt

    2010-01-01

    A study was conducted to propose a research-based model for a longitudinal data research system that addressed recommendations from a synthesis of literature related to: (1) needs reported by the U.S. Department of Education, (2) the twelve mandatory elements that define federally approved state longitudinal data systems (SLDS), (3) the…

  15. Colorado Longitudinal Twin Study of Reading Disability

    ERIC Educational Resources Information Center

    Wadsworth, Sally J.; DeFries, John C.; Olson, Richard K.; Willcutt, Erik G.

    2007-01-01

    The primary objectives of the present study are to introduce the Colorado Longitudinal Twin Study of Reading Disability, the first longitudinal twin study in which subjects have been specifically selected for having a history of reading difficulties, and to present some initial assessments of the stability of reading performance and cognitive…

  16. Fears in Czech Adolescents: A Longitudinal Study

    ERIC Educational Resources Information Center

    Michalcáková, Radka; Lacinová, Lenka; Kyjonková, Hana; Bouša, Ondrej; Jelínek, Martin

    2013-01-01

    The present study investigates developmental patterns of fear in adolescence. It is based on longitudinal data collected as a part of the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) project. A total of 186 Czech adolescents (43% girls) were assessed repeatedly at the age of 11, 13, and 15 years. The free-response method was…

  17. Fears in Czech Adolescents: A Longitudinal Study

    ERIC Educational Resources Information Center

    Michalcáková, Radka; Lacinová, Lenka; Kyjonková, Hana; Bouša, Ondrej; Jelínek, Martin

    2013-01-01

    The present study investigates developmental patterns of fear in adolescence. It is based on longitudinal data collected as a part of the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) project. A total of 186 Czech adolescents (43% girls) were assessed repeatedly at the age of 11, 13, and 15 years. The free-response method was…

  18. Colorado Longitudinal Twin Study of Reading Disability

    ERIC Educational Resources Information Center

    Wadsworth, Sally J.; DeFries, John C.; Olson, Richard K.; Willcutt, Erik G.

    2007-01-01

    The primary objectives of the present study are to introduce the Colorado Longitudinal Twin Study of Reading Disability, the first longitudinal twin study in which subjects have been specifically selected for having a history of reading difficulties, and to present some initial assessments of the stability of reading performance and cognitive…

  19. College Women's Female Friendships: A Longitudinal View

    ERIC Educational Resources Information Center

    Aleman, Ana M. Martinez

    2010-01-01

    This article presents a longitudinal qualitative study of the cognitive value of female friendships formed in college and seeks to appraise the meaning of the phenomenon for the participants. To grasp the temporal effects of the longitudinal data in this study, the author examines and assesses the relevant developmental literature, particularly…

  20. Modeling a Longitudinal Relational Research Data Systems

    ERIC Educational Resources Information Center

    Olsen, Michelle D. Hunt

    2010-01-01

    A study was conducted to propose a research-based model for a longitudinal data research system that addressed recommendations from a synthesis of literature related to: (1) needs reported by the U.S. Department of Education, (2) the twelve mandatory elements that define federally approved state longitudinal data systems (SLDS), (3) the…

  1. Longitudinal research in child and adolescent psychiatry.

    PubMed

    Verhulst, F C; Koot, H M

    1991-05-01

    An indispensable approach to the study of variations in individual development and of causal mechanisms and processes underlying the course of psychopathology is the longitudinal method. In this introductory review, the strengths and weaknesses of longitudinal research are discussed, and factors hampering progress in this field are outlined. The many advantages of this approach warrant continuing efforts to develop strategies that minimize its drawbacks.

  2. LSTGEE: longitudinal analysis of neuroimaging data

    NASA Astrophysics Data System (ADS)

    Li, Yimei; Zhu, Hongtu; Chen, Yasheng; An, Hongyu; Gilmore, John; Lin, Weili; Shen, Dinggang

    2009-02-01

    Longitudinal imaging studies are essential to understanding the neural development of neuropsychiatric disorders, substance use disorders, and normal brain. Using appropriate image processing and statistical tools to analyze the imaging, behavioral, and clinical data is critical for optimally exploring and interpreting the findings from those imaging studies. However, the existing imaging processing and statistical methods for analyzing imaging longitudinal measures are primarily developed for cross-sectional neuroimaging studies. The simple use of these cross-sectional tools to longitudinal imaging studies will significantly decrease the statistical power of longitudinal studies in detecting subtle changes of imaging measures and the causal role of time-dependent covariate in disease process. The main objective of this paper is to develop longitudinal statistics toolbox, called LSTGEE, for the analysis of neuroimaging data from longitudinal studies. We develop generalized estimating equations for jointly modeling imaging measures with behavioral and clinical variables from longitudinal studies. We develop a test procedure based on a score test statistic and a resampling method to test linear hypotheses of unknown parameters, such as associations between brain structure and function and covariates of interest, such as IQ, age, gene, diagnostic groups, and severity of disease. We demonstrate the application of our statistical methods to the detection of the changes of the fractional anisotropy across time in a longitudinal neonate study. Particularly, our results demonstrate that the use of longitudinal statistics can dramatically increase the statistical power in detecting the changes of neuroimaging measures. The proposed approach can be applied to longitudinal data with multiple outcomes and accommodate incomplete and unbalanced data, i.e., subjects with different number of measurements.

  3. EMS in Mauritius.

    PubMed

    Ramalanjaona, Georges; Brogan, Gerald X

    2009-02-01

    Mauritius lies in the southwest Indian Ocean about 1250 miles from the African coast and 500 miles from Madagascar. Mauritius (estimated population 1,230,602) became independent from the United Kingdom in 1968 and has one of the highest GDP per capita in Africa. Within Mauritius there is a well established EMS system with a single 999 national dispatch system. Ambulances are either publicly or privately owned. Public ambulances are run by the Government (SAMU). Megacare is a private subscriber only ambulance service. The Government has recently invested in new technology such as telemedicine to further enhance the role of EMS on the island. This article describes the current state of EMS in Mauritius and depicts its development in the context of Government effort to decentralise and modernise the healthcare system.

  4. EMS -- Error Message Service

    NASA Astrophysics Data System (ADS)

    Rees, P. C. T.; Chipperfield, A. J.; Draper, P. W.

    This document describes the Error Message Service, EMS, and its use in system software. The purpose of EMS is to provide facilities for constructing and storing error messages for future delivery to the user -- usually via the Starlink Error Reporting System, ERR (see SUN/104). EMS can be regarded as a simplified version of ERR without the binding to any software environment (e.g., for message output or access to the parameter and data systems). The routines in this library conform to the error reporting conventions described in SUN/104. A knowledge of these conventions, and of the ADAM system (see SG/4), is assumed in what follows. This document is intended for Starlink systems programmers and can safely be ignored by applications programmers and users.

  5. Left atrial longitudinal strain by speckle tracking echocardiography correlates well with left ventricular filling pressures in patients with heart failure

    PubMed Central

    2010-01-01

    Background The combination of early transmitral inflow velocity and mitral annular tissue Doppler imaging (E/Em ratio) is widely applied to noninvasively estimate left ventricular (LV) filling pressures. However E/Em ratio has a significant gray zone and its accuracy in patients with heart failure is debated. Left atrial (LA) deformation analysis by speckle tracking echocardiography (STE) was recently proposed as an alternative approach to estimate LV filling pressures. This study aimed at exploring the correlation of LA longitudinal function by STE and Doppler measurements with direct measurements of LV filling pressures in patients with heart failure. Methods A total of 36 patients with advanced systolic heart failure (ejection fraction ≤35%), undergoing right heart catheterization, were studied. Simultaneously to pulmonary capillary wedge pressure (PCWP) determination, peak atrial longitudinal strain (PALS) and mean E/Em ratio were measured in all subjects by two independent operators. PALS values were obtained by averaging all segments (global PALS), and by separately averaging segments measured in the 4-chamber and 2-chamber views. Results Not significant correlation was found between mean E/Em ratio and PCWP (R = 0.15). A close negative correlation between global PALS and the PCWP was found (R = -0.81, p < 0.0001). Furthermore, global PALS demonstrated the highest diagnostic accuracy (AUC of 0.93) and excellent sensitivity and specificity of 100% and 93%, respectively, to predict elevated filling pressure using a cutoff value less than 15.1%. Bland-Altman analysis confirmed this close agreement between PCWP estimated by global PALS and invasive PCWP (mean bias 0.1 ± 8.0 mmHg). Conclusion In a group of patients with advanced systolic heart failure, E/Em ratio correlated poorly with invasively obtained LV filling pressures. However, LA longitudinal deformation analysis by STE correlated well with PCWP, providing a better estimation of LV filling pressures in

  6. Joint modeling of survival time and longitudinal outcomes with flexible random effects.

    PubMed

    Choi, Jaeun; Zeng, Donglin; Olshan, Andrew F; Cai, Jianwen

    2017-08-30

    Joint models with shared Gaussian random effects have been conventionally used in analysis of longitudinal outcome and survival endpoint in biomedical or public health research. However, misspecifying the normality assumption of random effects can lead to serious bias in parameter estimation and future prediction. In this paper, we study joint models of general longitudinal outcomes and survival endpoint but allow the underlying distribution of shared random effect to be completely unknown. For inference, we propose to use a mixture of Gaussian distributions as an approximation to this unknown distribution and adopt an Expectation-Maximization (EM) algorithm for computation. Either AIC and BIC criteria are adopted for selecting the number of mixtures. We demonstrate the proposed method via a number of simulation studies. We illustrate our approach with the data from the Carolina Head and Neck Cancer Study (CHANCE).

  7. Breaking of longitudinal Akhiezer-Polovin waves.

    PubMed

    Verma, Prabal Singh; Sengupta, Sudip; Kaw, Predhiman

    2012-03-23

    The breaking of longitudinal Akhiezer-Polovin (AP) waves is demonstrated using a one-dimensional simulation based on the Dawson sheet model. It is found that the AP longitudinal waves break through the process of phase mixing at an amplitude well below the breaking amplitude for AP waves, when subjected to arbitrarily small longitudinal perturbations. Results from the simulation show a good agreement with the Dawson phase mixing formula modified to include relativistic mass variation effects. This result may be of direct relevance to the laser- or particle-beam plasma wakefield experiments.

  8. National EMS Research Agenda.

    PubMed

    Sayre, M R; White, L J; Brown, L H; McHenry, S D

    2002-01-01

    Now, more than ever before, the spirit of the emergency services professional is recognized by people everywhere. Individuals from every walk of life comprehend the reality of the job these professionals do each day. Placing the safety of others above their own is their acknowledged responsibility. Rescue and treatment of ill and injured patients are their purpose as well as their gratification. The men and women who provide prehospital care are well aware of the unpredictable nature of emergency medical services (EMS). Prehospital care is given when and where it is needed: in urban settings with vertical challenges and gridlock; in rural settings with limited access; in confined spaces; within entrapments; or simply in the street, exposed to the elements. Despite the challenges, EMS professionals rise to the occasion to do their best with the resources available. Despite more than 30 years of dedicated service by thousands of EMS professionals, academic researchers, and public policy makers, the nation's EMS system is treating victims of illness and injury with little or no evidence that the care they provide is optimal. A national investment in the EMS research infrastructure is necessary to overcome obstacles currently impeding the accumulation of essential evidence of the effectiveness of EMS practice. Funding is required to train new researchers and to help them establish their careers. Financial backing is needed to support the development of effective prehospital treatments for the diseases that drive the design of the EMS system, including injury and sudden cardiac arrest. Innovative strategies to make EMS research easier to accomplish in emergency situations must be implemented. Researchers must have access to patient outcome information in order to evaluate and improve prehospital care. New biomedical and technical advances must be evaluated using scientific methodology. Research is the key to maintaining focus on improving the overall health of the

  9. A longitudinal study of confabulation.

    PubMed

    Dalla Barba, Gianfranco; Brazzarola, Marta; Marangoni, Sara; Barbera, Claudia; Zannoni, Ilaria

    2017-02-01

    Confabulation, the production of statements and actions that are unintentionally incongruous to the subject's history, background, present and future situation, is a rather infrequent disorder, observed in several conditions affecting the nervous system. Little is known about the quantitative and qualitative evolution of confabulation in time. In this study we evaluated longitudinally the evolution of this disorder in a group of severe confabulators, using the Confabulation Battery (CB), a sensitive tool to detect confabulations in various memory domains. It was found that confabulations were stable over time and not temporally limited. It was also found that "Habits Confabulations" (HCs), i.e., habits and repeated personal events mistaken as specific, unique past and future personal episodes, or well-known public events when semantic knowledge is concerned, was the more frequently observed type of confabulation. Confabulations were also more prominent in the domain of Temporal Consciousness (TC), i.e., a specific form of consciousness that allows individuals to remember their personal past, to be oriented in their present world and to predict their personal future, than in Knowing Consciousness (KC), i.e., a specific form of consciousness allowing individuals to be aware of past, present and future impersonal knowledge and information. Confabulations showed also persistence, i.e., confabulations at the same questions over time, and consistency, i.e., same type of confabulation at the same question over time. These findings are discussed within the framework of the Memory, Consciousness and Temporality Theory.

  10. Longitudinal Variations in Jupiter's Winds

    NASA Technical Reports Server (NTRS)

    Simon-Miller, Amy A.; Gierasch, P. J.; Tierney, G.

    2010-01-01

    Long-term studies of Jupiter's zonal wind field revealed temporal variations on the order of 20 to 40 m/s at many latitudes, greater than the typical data uncertainties of 1 to 10 m/s. No definitive periodicities were evident, however, though some latitudinally-confined signals did appear at periods relevant to the Quasi- Quadrennial Oscillation (Simon-Miller & Gierasch, Icarus, in press). As the QQO appears, from vertical temperature profiles, to propagate downward, it is unclear why a signal is not more obvious, unless other processes dominate over possibly weaker forcing from the QQO. An additional complication is that zonal wind profiles represent an average over some particular set of longitudes for an image pair and most data sets do not offer global wind coverage. Lien avoiding known features, such as the large anticyclonic vortices especially prevalent in the south, there can be distinct variations in longitude. We present results on the full wind field from Voyager and Cassini data, showing apparent longitudinal variations of up to 60 m/s or more. These are particularly obvious near disruptions such as the South Equatorial Disturbance, even when the feature itself is not clearly visible. These two dates represent very different states of the planet for comparison: Voyagers 1 & 2 flew by Jupiter shortly after a global upheaval, while many regions were in a disturbed state, while the Cassini view is typical of a more quiescent period present during much of the 1990s and early 2000s.

  11. Underemployment and depression: longitudinal relationships.

    PubMed

    Dooley, D; Prause, J; Ham-Rowbottom, K A

    2000-12-01

    We conceptualize employment status not as a dichotomy of working versus not working but as a continuum ranging from adequate employment to inadequate employment (involuntary part-time or low wage) to unemployment. Will shifts from adequate to inadequate employment increase depression as do shifts from employment to unemployment, and to what extent does prior depression select workers into such adverse employment change? We analyze panel data from the National Longitudinal Survey of Youth for the years 1992-1994 for the 5,113 respondents who were adequately employed in 1992. Controlling for prior depression, both types of adverse employment change resulted in similar, significant increases in depression. These direct effects persisted despite inclusion of such potential mediators as changes in income, job satisfaction, and marital status. Marital status buffered the depressive effect of both types of adverse change, but education and job dissatisfaction amplified the effect of unemployment on depression. Prior depression did not predict higher risk of becoming inadequately employed but did predict increased risk of unemployment, particularly for those with less education. These results confirm that both unemployment and inadequate employment affect mental health, and they invite greater efforts to monitor the extent and impact of underemployment.

  12. Longitudinal oscillation of launch vehicles

    NASA Technical Reports Server (NTRS)

    Glaser, R. F.

    1973-01-01

    During powered flight a vehicle may develop longitudinal self-excited oscillations, so-called oscillations, of its structure. The energy supplying the vibration is tapped from the thrust by the activity of the system itself; that is, oscillation of the structure causes oscillation of the propellant system, especially of the pumps. In this way an oscillating thrust can be created that, by a feedback loop, may sustain the structural oscillation under certain circumstances. Two special features of the system proved to be essential for creation of instability. One is the effect of the inherent time interval that the thrust oscillation is lagging behind the structural oscillation. The other is the decreased of system mass caused by the exhausting of gas. The latter feature may cause an initially stable system to become unstable. To examine the stability of the system, a single mass-spring model, which is the result of a one-term Galerkin approach to the equation of motion, has been considered. The Nyquist stability criterion leads to a stability graph that shows the stability conditions in terms of the system parameter and also demonstrates the significance of time lag, feedback magnitude, and loss of mass. An important conclusion can be drawn from the analysis: large relative displacements of the pump-engine masses favor instability. This is also confirmed by flight measurements.

  13. Longitudinal impedance of single frog muscle fibers

    PubMed Central

    1975-01-01

    The longitudinal impedance of single skeletal muscle fibers has been measured from1 to 10,000 Hz in an oil gap apparatus which forces current to flow longitudinally down the fiber. The impedance observed is purely resistive in some fibers from the semitendinosus muscle and in two fibers from the sartorius muscle. In other fibers from the semitendinosus muscle a small phase shift is observed. The mean value of the maximum phase shift observed from all fibers is 1.07 degrees. The artifacts associated with the apparatus and method are examined theoretically and it is shown that one of the likely artifacts could account for the small phase observed. It is concluded that the longitudinal impedance of skeletal muscle fibers is essentially resistive and that little, if any, longitudinal current crosses the membranes of the sarcoplasmic reticulum. PMID:1078575

  14. Longitudinally extensive optic neuritis in pediatric patients.

    PubMed

    Graves, Jennifer; Kraus, Verena; Soares, Bruno P; Hess, Christopher P; Waubant, Emmanuelle

    2015-01-01

    Extensive optic nerve demyelinating lesions on magnetic resonance imaging (MRI) in adults could indicate a diagnosis other than multiple sclerosis with worse prognosis such as neuromyelitis optica. We report the frequency of longitudinally extensive lesions in children with first events of optic neuritis. Subjects had brain or orbit MRI within 3 months of onset and were evaluated at the University of California, San Francisco, Pediatric Multiple Sclerosis Center. Lesion length, determined by T2 hyperintensity or contrast enhancement, was blindly graded as absent, focal or longitudinally extensive (at least 2 contiguous segments of optic nerve). Of 25 subjects, 9 (36%) had longitudinally extensive optic neuritis. Extensive lesions were not associated with non-multiple sclerosis versus multiple sclerosis diagnosis (P = 1.00). No association between age and lesion extent was observed (P = .26). Prospective studies are needed to determine if longitudinally extensive optic neuritis can predict visual outcome.

  15. Ultimate Longitudinal Strength of Composite Ship Hulls

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangming; Huang, Lingkai; Zhu, Libao; Tang, Yuhang; Wang, Anwen

    2017-01-01

    A simple analytical model to estimate the longitudinal strength of ship hulls in composite materials under buckling, material failure and ultimate collapse is presented in this paper. Ship hulls are regarded as assemblies of stiffened panels which idealized as group of plate-stiffener combinations. Ultimate strain of the plate-stiffener combination is predicted under buckling or material failure with composite beam-column theory. The effects of initial imperfection of ship hull and eccentricity of load are included. Corresponding longitudinal strengths of ship hull are derived in a straightforward method. A longitudinally framed ship hull made of symmetrically stacked unidirectional plies under sagging is analyzed. The results indicate that present analytical results have a good agreement with FEM method. The initial deflection of ship hull and eccentricity of load can dramatically reduce the bending capacity of ship hull. The proposed formulations provide a simple but useful tool for the longitudinal strength estimation in practical design.

  16. Transverse-longitudinal coupling in intense beams

    SciTech Connect

    Wang, T.S.F.; Smith, L.

    1981-03-01

    The coupling between transverse and longitudinal perturbations is studied self-consistently by considering a beam of K-V distribution. The analysis is carried out within the context of linearized Vlasov-Maxwell equations and electrostatic approximation. The perturbation is assumed to be azimuthally symmetric but axially non-uniform (k/sub z/ is not equal to 0). It is shown that the coupling affects both the longitudinal and transverse modes significantly in the high density and low frequency region. Two new classes of longitudinal modes are found which would not exist if the transverse motions of particles are neglected. The effect of resistive wall impedance on beam stability is also studied. It is found that the longitudinal impedance can cause the transverse modes also to be weakly unstable.

  17. The Lighthouse Program: A Longitudinal Research Project.

    ERIC Educational Resources Information Center

    LaRose, Barbara

    1986-01-01

    Longitudinal data are presented from the Lighthouse Program for gifted students which features cluster grouping and a quota identification systems to ensure proportionate inclusion of minority students. (Author/CL)

  18. Longitudinal research strategies: advantages, problems, and prospects.

    PubMed

    Farrington, D P

    1991-05-01

    The single-cohort, long-term longitudinal survey has many advantages in comparison with a cross-sectional survey in advancing knowledge about offending and other types of psychopathology, notably in providing information about onset and desistance, about continuity and prediction, and about within-individual change. However, the longitudinal survey also has significant problems, notably in confounding aging and period effects, delayed results, achieving continuity in funding and research direction, and cumulative attrition. This paper suggests the use of a multiple-cohort sequential strategy (the "accelerated longitudinal design") as a way of achieving the benefits of the longitudinal method while minimizing the problems in advancing knowledge about the natural history, causes, prevention, and treatment of psychopathological disorders.

  19. FDTD analysis of dielectric-loaded longitudinally slotted rectangular waveguides.

    PubMed

    Al-Rizzo, Hussain M; Younies, Hassan Z; Clark, Ken G; Tranquilla, Jim M

    2003-01-01

    A versatile electromagnetic (EM) computational algorithm, based on the Finite-Difference Time-Domain (FDTD) technique, is developed to analyze longitudinally oriented, square-ended, single slot fixtures and slot-pair configurations cut in the broad wall of a WR-975 guide operating at a frequency of 915 MHz. The finite conductivity of the waveguide walls is accounted for by employing a time-domain Surface-Impedance Boundary Conditions (SIBC) formulation. The proposed FDTD algorithm has been validated against measurements performed on a probe-excited slot cut along the center line of the broad wall of a WR-284 guide and available experimental data for energy coupled from a longitudinal slot pair in the broad wall of a WR-340 guide. Numerical results are-presented to exploit the influence of the constitutive parameters of the processed material as well as protective insulating window slabs mounted on the exterior surface of the slots. Particular attention is given to the resonant length, scattering parameters, and the electric field distribution within lossy objects placed in the near-field region over a range of slot offsets and workloads with extensive results being reported for the first time. It is shown that the FDTD technique can accurately predict the coupling and power absorption characteristics in loads located in the near field zone of the slotted waveguide structures and, therefore, should prove to be a powerful design tool applicable to a wide class of slotted waveguide applicators that may be difficult to analyze using other available techniques.

  20. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Longitudinal control. 23.145 Section 23.145... Maneuverability § 23.145 Longitudinal control. (a) With the airplane as nearly as possible in trim at 1.3 VS1, it... application of single-handed control forces exceeding those specified in § 23.143(c). The trimming...

  1. Longitudinal space charge effects near transition

    SciTech Connect

    Pozdeyev,E.; Rodriguez, J.A.; Marti, F.; York, R.C.

    2009-05-04

    Experimental and numerical studies of the longitudinal beam dynamics in the Small Isochronous Ring (SIR) at Michigan State University revealed a fast, space-charge driven instability that did not fit the model of the negative mass instability. This paper proposes a simple analytical model explaining these results. Also, the paper compares the model to result s of experimental and numerical studies of the longitudinal beam dynamics in SIR.

  2. Longitudinal study of keratoconus progression.

    PubMed

    Li, Xiaohui; Yang, Huiying; Rabinowitz, Yaron S

    2007-10-01

    To determine if differences in topographic progression between unaffected keratoconus relatives and normal controls can predict factors associated with the development of keratoconus in a longitudinal study. We recruited 369 unaffected keratoconus relatives and 119 normal controls in Los Angeles. Both eyes of subjects were examined at baseline clinically and by quantitative videokeratography and at a period ranging from 1 year to 8 years. Progression to keratoconus was evaluated by quantitative videokeratography variables. Unaffected relatives had higher Central K (CK), I-S and KISA values and were younger than normal controls (CK: 44.70 vs 44.01, P<0.01; I-S: 0.76 vs 0.58, P<0.01, KISA: 29.97 vs 23.89, P=0.02; age: 34.8 vs 41.0, P<0.01) at baseline. All three indices significantly increased with age, and CK and KISA values were associated with a positive family history for keratoconus (P<0.001 for CK and P=0.05 for KISA), however, the two groups were not statistically different in progression of keratoconus. After grouping unaffected relatives as high risk (age< or = 30 or Central K > or = 47.2 and I-S> or =1.2 or KISA> or = 60) and low risk (age>30 and Central K<47.2 and I-S<1.2 and KISA< 60), relatives in the high risk group had a greater increase in CK and I-S values than those in the low risk group (CK: P=0.009; I-S: P<0.001), which indicated that there were significantly different rates of progression between two groups. Unaffected relatives had higher videokeratography indices than normal controls, but overall they did not progress to keratoconus quicker than normal controls. However, relatives in the high risk group may have a greater risk of progression to keratoconus.

  3. Longitudinal study of keratoconus progression

    PubMed Central

    Li, Xiaohui; Yang, Huiying; Rabinowitz, Yaron S.

    2013-01-01

    To determine if differences in topographic progression between unaffected keratoconus relatives and normal controls can predict factors associated with the development of keratoconus in a longitudinal study. We recruited 369 unaffected keratoconus relatives and 119 normal controls in Los Angeles. Both eyes of subjects were examined at baseline clinically and by quantitative videokeratography and at a period ranging from 1 year to 8 years. Progression to keratoconus was evaluated by quantitative videokeratography variables. Unaffected relatives had higher Central K (CK), I-S and KISA values and were younger than normal controls (CK: 44.70 vs 44.01, P<0.01; I-S: 0.76 vs 0.58, P<0.01, KISA: 29.97 vs 23.89, P=0.02; age: 34.8 vs 41.0, P<0.01) at baseline. All three indices significantly increased with age, and CK and KISA values were associated with a positive family history for keratoconus (P<0.001 for CK and P=0.05 for KISA), however, the two groups were not statistically different in progression of keratoconus. After grouped unaffected relatives as the high risk (age<=30 or Central K>=47.2 or I-S >=1.2 or KISA>=60) and the low risk (age>30 and Central K<47.2 and I-S <1.2 and KISA<60), relatives in the high risk group had a greater increase in CK and I-S values than those in the low risk group (CK: p=0.009; I-S: p<0.001), which indicated that there were significantly different rates of progression between two groups. Unaffected relatives had higher videokeratography indices than normal controls, but overall they did not progress to keratoconus quicker than normal controls. However, relatives in a high risk group may have a greater risk of progression to keratoconus. PMID:17681291

  4. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Demonstration of static longitudinal... Demonstration of static longitudinal stability. Static longitudinal stability must be shown as follows: (a... need not be less than 1.3 V SR 1. (b) Cruise. Static longitudinal stability must be shown in the...

  5. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Demonstration of static longitudinal... Demonstration of static longitudinal stability. Static longitudinal stability must be shown as follows: (a... need not be less than 1.3 V SR 1. (b) Cruise. Static longitudinal stability must be shown in the...

  6. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Demonstration of static longitudinal... Demonstration of static longitudinal stability. Static longitudinal stability must be shown as follows: (a... need not be less than 1.3 V SR 1. (b) Cruise. Static longitudinal stability must be shown in the...

  7. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Demonstration of static longitudinal... Demonstration of static longitudinal stability. Static longitudinal stability must be shown as follows: (a... need not be less than 1.3 V SR 1. (b) Cruise. Static longitudinal stability must be shown in the...

  8. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Demonstration of static longitudinal... Demonstration of static longitudinal stability. Static longitudinal stability must be shown as follows: (a... need not be less than 1.3 V SR 1. (b) Cruise. Static longitudinal stability must be shown in the...

  9. The EM Earthquake Precursor

    NASA Astrophysics Data System (ADS)

    Jones, K. B., II; Saxton, P. T.

    2013-12-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

  10. Astronomia para/com crianças carentes em Limeira

    NASA Astrophysics Data System (ADS)

    Bretones, P. S.; Oliveira, V. C.

    2003-08-01

    Em 2001, o Instituto Superior de Ciências Aplicadas (ISCA Faculdades de Limeira) iniciou um projeto pelo qual o Observatório do Morro Azul empreendeu uma parceria com o Centro de Promoção Social Municipal (CEPROSOM), instituição mantida pela Prefeitura Municipal de Limeira para atender crianças e adolescentes carentes. O CEPROSOM contava com dois projetos: Projeto Centro de Convivência Infantil (CCI) e Programa Criança e Adolescente (PCA), que atendiam crianças e adolescentes em Centros Comunitários de diversas áreas da cidade. Esses projetos têm como prioridades estabelecer atividades prazerosas para as crianças no sentido de retirá-las das ruas. Assim sendo, as crianças passaram a ter mais um tipo de atividade - as visitas ao observatório. Este painel descreve as várias fases do projeto, que envolveu: reuniões de planejamento, curso de Astronomia para as orientadoras dos CCIs e PCAs, atividades relacionadas a visitas das crianças ao Observatório, proposta de construção de gnômons e relógios de Sol nos diversos Centros Comunitários de Limeira e divulgação do projeto na imprensa. O painel inclui discussões sobre a aprendizagem de crianças carentes, relatos que mostram a postura das orientadoras sobre a pertinência do ensino de Astronomia, relatos do monitor que fez o atendimento no Observatório e o que o número de crianças atendidas representou para as atividades da instituição desde o início de suas atividades e, em particular, em 2001. Os resultados são baseados na análise de relatos das orientadoras e do monitor do Observatório, registros de visitas e matérias da imprensa local. Conclui com uma avaliação do que tal projeto representou para as Instituições participantes. Para o Observatório, em particular, foi feita uma análise com relação às outras modalidades de atendimentos que envolvem alunos de escolas e público em geral. Também é abordada a questão do compromisso social do Observatório na educação do

  11. EMS & the DEA.

    PubMed

    Beeson, Jeff; Ayres, Chris

    2010-01-01

    It's clear that EMS medical directors and management staff must be vigilant in their oversight of implementation, administration and monitoring of controlled substances within their agencies to best serve the public and avoid running afoul of investigation and incurring significant penalties. Those potentially affected by the need for individual registrations of both emergency vehicles and central inventory systems should carefully monitor upcoming developments in the interpretation od DEA regulations.

  12. Monitoring Survivability and Infectivity of Porcine Epidemic Diarrhea Virus (PEDv) in the Infected On-Farm Earthen Manure Storages (EMS).

    PubMed

    Tun, Hein M; Cai, Zhangbin; Khafipour, Ehsan

    2016-01-01

    In recent years, porcine epidemic diarrhea virus (PEDv) has caused major epidemics, which has been a burden to North America's swine industry. Low infectious dose and high viability in the environment are major challenges in eradication of this virus. To further understand the viability of PEDv in the infected manure, we longitudinally monitored survivability and infectivity of PEDv in two open earthen manure storages (EMS; previously referred to as lagoon) from two different infected swine farms identified in the province of Manitoba, Canada. Our study revealed that PEDv could survive up to 9 months in the infected EMS after the initial outbreak in the farm. The viral load varied among different layers of the EMS with an average of 1.1 × 10(5) copies/ml of EMS, independent of EMS temperature and pH. In both studied EMS, the evidence of viral replication was observed through increased viral load in the later weeks of the samplings while there was no new influx of infected manure into the EMS, which was suggestive of presence of potential alternative hosts for PEDv within the EMS. Decreasing infectivity of virus over time irrespective of increased viral load suggested the possibility of PEDv evolution within the EMS and perhaps in the new host that negatively impacted virus infectivity. Viral load in the top layer of the EMS was low and mostly non-infective suggesting that environmental factors, such as UV and sunlight, could diminish the replicability and infectivity of the virus. Thus, frequent agitation of the EMS that could expose virus to UV and sunlight might be a potential strategy for reduction of PEDv load and infectivity in the infected EMS.

  13. Monitoring Survivability and Infectivity of Porcine Epidemic Diarrhea Virus (PEDv) in the Infected On-Farm Earthen Manure Storages (EMS)

    PubMed Central

    Tun, Hein M.; Cai, Zhangbin; Khafipour, Ehsan

    2016-01-01

    In recent years, porcine epidemic diarrhea virus (PEDv) has caused major epidemics, which has been a burden to North America’s swine industry. Low infectious dose and high viability in the environment are major challenges in eradication of this virus. To further understand the viability of PEDv in the infected manure, we longitudinally monitored survivability and infectivity of PEDv in two open earthen manure storages (EMS; previously referred to as lagoon) from two different infected swine farms identified in the province of Manitoba, Canada. Our study revealed that PEDv could survive up to 9 months in the infected EMS after the initial outbreak in the farm. The viral load varied among different layers of the EMS with an average of 1.1 × 105 copies/ml of EMS, independent of EMS temperature and pH. In both studied EMS, the evidence of viral replication was observed through increased viral load in the later weeks of the samplings while there was no new influx of infected manure into the EMS, which was suggestive of presence of potential alternative hosts for PEDv within the EMS. Decreasing infectivity of virus over time irrespective of increased viral load suggested the possibility of PEDv evolution within the EMS and perhaps in the new host that negatively impacted virus infectivity. Viral load in the top layer of the EMS was low and mostly non-infective suggesting that environmental factors, such as UV and sunlight, could diminish the replicability and infectivity of the virus. Thus, frequent agitation of the EMS that could expose virus to UV and sunlight might be a potential strategy for reduction of PEDv load and infectivity in the infected EMS. PMID:27014197

  14. LONGITUDINAL SPACE CHARGE EFFECT FOR SNS

    SciTech Connect

    ZHANG,S.Y.; WENG,W.T.

    1998-06-22

    One of performance requirements of the Spallation Neutron Source (SNS) is to keep the uncontrolled beam loss in the storage ring to less than 2 x 10{sup {minus}4} per pulse. For 2 MW SNS, the maximum beam intensity is N = 2 x 10{sup 14} protons per ring. Since the bunch lengthening has impact on both the extraction beam loss and the lowering of e-p instability threshold, the longitudinal space charge effect requires attentions. Such a space charge effect has been studied both analytically and using computer simulations. The longitudinal space charge effect, which is a defocusing force below transition, is a plausible source of the bunch leakage. In this article, the total RF potential, which takes into account the space charge effect together with the RF power, is used to provide analytical predictions for the bunch lengthening. The prediction is confirmed by the computer simulation. It is found that for 2 MW SNS storage ring, the longitudinal space charge induced bunch leakage into the interbunch gap is not significant. Therefore, corrections to the longitudinal space charge impedance, such as the proposed ferrite insertion in the PSR ring, are probably not necessary. Applying an RF voltage ramping from 20 KV to 40 KV during the multiturn injection can further cut the bunch leakage to a negligible degree. The same approach applied to the PSR shows that the longitudinal space charge effect does cause sizable bunch leakage at the intensity limit encountered there.

  15. Longitudinal stability in multiharmonic standing wave linacs

    DOE PAGES

    Carver, L. R.; Jones, R. M.; Jiang, Y.; ...

    2016-09-22

    Accelerating cavities that excite multiple modes at integer harmonics of the fundamental frequency have the potential to be used to suppress the onset of rf breakdown and reduce the pulsed surface heating at high accelerating gradients. Understanding the effect of an additional harmonic cavity mode on the longitudinal beam dynamics is important to their development and use. A Hamiltonian that describes the longitudinal motion of a particle as it traverses a chain of multiharmonic cavities has been derived and is applied to the case of a second harmonic cavity. The Hamiltonian is based upon formalisms found in literature for themore » fundamental harmonic and is extended to include different longitudinal field distributions and harmonic frequencies. The study initially explores the longitudinal motion for moderate accelerating gradients with high-β protons, as this will allow fundamental properties of the stable region (acceptance and shape of the rf bucket) to be determined. High accelerating gradients are also investigated but the focus will be on phase stability throughout. Finally, this work concludes by considering the longitudinal dynamics of a modified European Spallation Source accelerator, comprised of multiharmonic cavities that has specifications broadly consistent with the accelerator.« less

  16. Longitudinal stability in multiharmonic standing wave linacs

    NASA Astrophysics Data System (ADS)

    Carver, L. R.; Jones, R. M.; Jiang, Y.; Hirshfield, J. L.

    2016-09-01

    Accelerating cavities that excite multiple modes at integer harmonics of the fundamental frequency have the potential to be used to suppress the onset of rf breakdown and reduce the pulsed surface heating at high accelerating gradients. Understanding the effect of an additional harmonic cavity mode on the longitudinal beam dynamics is important to their development and use. A Hamiltonian that describes the longitudinal motion of a particle as it traverses a chain of multiharmonic cavities has been derived and is applied to the case of a second harmonic cavity. The Hamiltonian is based upon formalisms found in literature for the fundamental harmonic and is extended to include different longitudinal field distributions and harmonic frequencies. The study initially explores the longitudinal motion for moderate accelerating gradients with high-β protons, as this will allow fundamental properties of the stable region (acceptance and shape of the rf bucket) to be determined. High accelerating gradients are also investigated but the focus will be on phase stability throughout. This work concludes by considering the longitudinal dynamics of a modified European Spallation Source accelerator, comprised of multiharmonic cavities that has specifications broadly consistent with the accelerator.

  17. Longitudinal fluctuations and decorrelation of anisotropic flow

    NASA Astrophysics Data System (ADS)

    Pang, Long-Gang; Petersen, Hannah; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian

    2016-12-01

    We investigate the decorrelation of 2nd and 3rd order anisotropic flow for charged particles in two different pseudo rapidity (η) windows by varying the pseudo rapidity gap, in an event-by-event (3+1)D ideal hydrodynamic model, with fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. We visualize the parton distribution at initial state for Pb+Pb collisions at LHC and Au+Au collisions at RHIC, and demonstrate the longitudinal fluctuations originating from the asymmetry between forward and backward going participants, the fluctuations of the string length and the fluctuations due to finite number of partons at different beam energies. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation than at LHC, indicating larger longitudinal fluctuations at lower beam energies.

  18. 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.

  19. Bunched beam longitudinal instability: Coherent dipole motion

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1993-04-23

    In this paper, the authors present a new formulation for the longitudinal coherent dipole motion, where a quadrature response of the environmental impedance is shown to be the effective longitudinal impedance for the beam instability. The Robinson-Pedersen formulation for the longitudinal dipole motion is also presented, the difference of the two approaches is discussed in the comparison. The results by using the Sacherer integral equation for the coherent dipole motion can generate the same results as by using the other two approaches, except for a scaling difference. The formulation is further generalized to the rigid bunch motion using signal analysis method, where a form factor shows up naturally. Finally, the formulation is applied to solve the coupled bunch instabilities. Examples of the AGS Booster and the AGS coupled bunch instabilities are used to illustrate the applications of the formulation.

  20. Entanglement from longitudinal and scalar photons

    SciTech Connect

    Franson, J. D

    2011-09-15

    The covariant quantization of the electromagnetic field in the Lorentz gauge gives rise to longitudinal and scalar photons in addition to the usual transverse photons. It is shown here that the exchange of longitudinal and scalar photons can produce entanglement between two distant atoms or harmonic oscillators. The form of the entangled states produced in this way is very different from that obtained in the Coulomb gauge, where the longitudinal and scalar photons do not exist. A generalized gauge transformation is used to show that all physically observable effects are the same in the two gauges, despite the differences in the form of the entangled states. An approach of this kind may be useful for a covariant description of the dynamics of quantum information processing.

  1. Symmetric diffeomorphic modeling of longitudinal structural MRI.

    PubMed

    Ashburner, John; Ridgway, Gerard R

    2012-01-01

    This technology report describes the longitudinal registration approach that we intend to incorporate into SPM12. It essentially describes a group-wise intra-subject modeling framework, which combines diffeomorphic and rigid-body registration, incorporating a correction for the intensity inhomogeneity artifact usually seen in MRI data. Emphasis is placed on achieving internal consistency and accounting for many of the mathematical subtleties that most implementations overlook. The implementation was evaluated using examples from the OASIS Longitudinal MRI Data in Non-demented and Demented Older Adults.

  2. Symmetric Diffeomorphic Modeling of Longitudinal Structural MRI

    PubMed Central

    Ashburner, John; Ridgway, Gerard R.

    2013-01-01

    This technology report describes the longitudinal registration approach that we intend to incorporate into SPM12. It essentially describes a group-wise intra-subject modeling framework, which combines diffeomorphic and rigid-body registration, incorporating a correction for the intensity inhomogeneity artifact usually seen in MRI data. Emphasis is placed on achieving internal consistency and accounting for many of the mathematical subtleties that most implementations overlook. The implementation was evaluated using examples from the OASIS Longitudinal MRI Data in Non-demented and Demented Older Adults. PMID:23386806

  3. Why do Emergency Medical Services (EMS) Professionals Leave EMS?

    PubMed

    Blau, Gary; Chapman, Susan A

    2016-12-01

    The objective was to determine why Emergency Medical Technician (EMT)-Basics and Paramedics leave the Emergency Medical Services (EMS) workforce. Data were collected through annual surveys of nationally registered EMT-Basics and Paramedics from 1999 to 2008. Survey items dealing with satisfaction with the EMS profession, likelihood of leaving the profession, and likelihood of leaving their EMS job were assessed for both EMT-Basics and Paramedics, along with reasons for leaving the profession. Individuals whose responses indicated that they were not working in EMS were mailed a special exit survey to determine the reasons for leaving EMS. The likelihood of leaving the profession in the next year was low for both EMT-Basics and Paramedics. Although overall satisfaction levels with the profession were high, EMT-Basics were significantly more satisfied than Paramedics. The most important reasons for leaving the profession were choosing to pursue further education and moving to a new location. A desire for better pay and benefits was a significantly more important reason for EMT-Paramedics' exit decisions than for EMT-Basics. Given the anticipated increased demand for EMS professionals in the next decade, continued study of issues associated with retention is strongly recommended. Some specific recommendations and suggestions for promoting retention are provided. Blau G , Chapman SA . Why do Emergency Medical Services (EMS) professionals leave EMS? Prehosp Disaster Med. 2016;31(Suppl. 1):s105-s111.

  4. Compensation, benefits, and satisfaction: the Longitudinal Emergency Medical Technician Demographic Study (LEADS) Project.

    PubMed

    Brown, William E; Dawson, Drew; Levine, Roger

    2003-01-01

    To determine the compensation, benefit package, and level of satisfaction with the benefits of nationally registered emergency medical technicians (NREMTs) in 2001. The Longitudinal EMT Attribute Demographic Study (LEADS) Project included an 18-question snapshot survey on compensation with the 2001 core survey. This survey was sent to 4,835 randomly selected NREMTs. A total of 1,718 NREMT-Basics and NREMT-Paramedics, from 1,317 different postal zip codes, responded to the survey. Most NREMTs in the survey (86% of the compensated NREMT-Basics and 85% of the compensated NREMT-Paramedics) were employed primarily as patient care providers. For their emergency medical services (EMS) work in the previous 12 months, compensated NREMT-Basics had mean earnings of 18,324 US dollars (standard error, 978 US dollars) and compensated NREMT-Paramedics had mean earnings of 34,654 US dollars (standard error, 646 US dollars). At least 26% of compensated NREMT-Basics and 9% of compensated NREMT-Paramedics had no health insurance. The majority of compensated NREMTs (62% of the Basics and 57% of the Paramedics) reported their retirement plans were not adequate to meet their financial needs. EMTs are not satisfied with the appreciation and recognition they receive from EMS employers. About one-third (35% of the compensated NREMT-Basics and 30% of the compensated NREMT-Paramedics) were not satisfied with all of the benefits they receive from their EMS employer. Nearly all (94% of both compensated NREMT-Basics and NREMT-Paramedics) believed that EMTs should be paid more for the job that they do. The adequacy of EMT compensation and benefit packages is an area of concern. It is not unreasonable to believe that these factors are associated with EMT retention and attrition. Additional longitudinal EMT information on compensation and benefits are anticipated to determine the extent to which compensation and benefits are factors in EMT retention.

  5. What Can We Learn From Longitudinal Studies of Adult Development?

    PubMed Central

    Schaie, K. Warner

    2005-01-01

    This article distinguishes between normal and pathological aging, provides an interdisciplinary context, and then considers a sample case of cognitive aging. Developmental influences on cognition include the physiological infrastructure, genetic predispositions, and environmental influences. Different types of longitudinal studies are distinguished, and contrasting findings of cross-sectional and longitudinal are examined in the sample case of the Seattle Longitudinal Study. Also considered is the longitudinal context for intervention studies and the role of longitudinal family studies in assessing rate of aging and generational differences in rates of aging. Finally, attention is given to the role of longitudinal studies in the early detection of risk for dementia in advanced age. PMID:16467912

  6. Combined longitudinal and lateral control for automated vehicle guidance

    NASA Astrophysics Data System (ADS)

    Attia, Rachid; Orjuela, Rodolfo; Basset, Michel

    2014-02-01

    This paper deals with the longitudinal and lateral control of an automotive vehicle within the framework of fully automated guidance. The automotive vehicle is a complex system characterised by highly nonlinear longitudinal and lateral coupled dynamics. Consequently, automated guidance must be simultaneously performed with longitudinal and lateral control. This work presents an automated steering strategy based on nonlinear model predictive control. A nonlinear longitudinal control strategy considering powertrain dynamics is also proposed to cope with the longitudinal speed tracking problem. Finally, a simultaneous longitudinal and lateral control strategy helps to improve the combined control performance. This whole control strategy is tested through simulations showing the effectiveness of the present approach.

  7. Longitudinal magnetization loss in twisted multifilamentary Bi2223 tape

    NASA Astrophysics Data System (ADS)

    Amemiya, N.; Rabbers, J.-J.; Krooshoop, B. E.; ten Haken, B.; ten Kate, H.; Ayai, N.; Hayashi, K.

    2002-08-01

    Multifilamentary Bi2223 tapes are exposed to the longitudinal magnetic field as well as the transverse one in some electrical power apparatuses such as multilayer power transmission cables. Here, we define the longitudinal and transverse magnetic fields as the field components parallel and perpendicular to the tape axis, respectively. If the filament-bundle is twisted, it can couple to the AC longitudinal magnetic field to generate the longitudinal magnetization loss. Furthermore, the AC transport current flowing spirally in the twisted filament-bundle possibly influences the longitudinal magnetization. The longitudinal magnetization loss was measured in a twisted multifilamentary Bi2223 tape exposed to longitudinal magnetic field and carrying the transport current. The measured longitudinal magnetization loss in the twisted tape exposed to the longitudinal magnetic field is larger than that in another untwisted tape. Supplying the AC transport current changes the longitudinal magnetization loss in the twisted tape exposed to the AC longitudinal magnetic field. The influence of the transport current depends on the phase relation between the longitudinal magnetic field and the transport current. If their phase difference is 0°, the longitudinal magnetization loss decreases remarkably with increasing amplitude of the transport current. It means that the change in the current distribution due to the transport current results in the decrease in the power flow from the magnet power supply. But, a preliminary measurement of the transport loss shows that the total loss increases with increasing transport current.

  8. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  9. Collaborative Knowledge-Building: A Longitudinal Study

    ERIC Educational Resources Information Center

    Li, Qing

    2009-01-01

    The focus of this paper is on knowledge-building in a technology-supported learning environment in higher education through a longitudinal study of a graduate course from 2003 to 2007. The primary question is: how do learning conditions designed into a graduate course contribute to collaborative knowledge building? In particular, two major…

  10. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  11. Delinquency Prone Youth: Longitudinal and Preventive Research.

    ERIC Educational Resources Information Center

    Benning, James J.; And Others

    The first two phases of the EAU Claire County Youth Study were concerned with the relationships between classroom behavior and various facets of the child's family life. Phase II took two forms: (1) a major longitudinal evaluation of the relationships among classroom aggression, social adjustment, subsequent academic achievement, and juvenile…

  12. Managing Organizational Commitment: Insights from Longitudinal Research

    ERIC Educational Resources Information Center

    Morrow, Paula C.

    2011-01-01

    This article summarizes what is known about the "active" management of affective organizational commitment (AOC) through a review of 58 studies employing longitudinal research designs. The review yields six broad categories of antecedents that have empirically demonstrated effects on AOC: socialization practices, organizational changes, human…

  13. Teaching Technology Longitudinally to Virtual Children

    ERIC Educational Resources Information Center

    Matthews, Lynley

    2010-01-01

    Children of Generation Y are entering our schooling system. These children have always known instant communication and the internet. They possess basic skills in using technology, but they still need to develop a deeper understanding of technology. Teaching longitudinally will increase the learner's confidence and develop a deeper understanding.…

  14. Conducting Three-Level Longitudinal Analyses

    ERIC Educational Resources Information Center

    Peugh, James L.; Heck, Ronald H.

    2017-01-01

    Researchers in the field of early adolescence interested in quantifying the environmental influences on a response variable of interest over time would use cluster sampling (i.e., obtaining repeated measures from students nested within classrooms and/or schools) to obtain the needed sample size. The resulting longitudinal data would be nested at…

  15. Longitudinal Predictors of High School Completion

    ERIC Educational Resources Information Center

    Barry, Melissa; Reschly, Amy L.

    2012-01-01

    This longitudinal study examined predictors of dropout assessed in elementary school. Student demographic data, achievement, attendance, and ratings of behavior from the Behavior Assessment System for Children were used to predict dropout and completion. Two models, which varied on student sex and race, predicted dropout at rates ranging from 75%…

  16. The Tevatron bunch by bunch longitudinal dampers

    SciTech Connect

    Cheng-Yang Tan and James Steimel

    2002-09-25

    We describe in this paper the Tevatron bunch by bunch dampers. The goal of the dampers is to stop the spontaneous longitudinal beam size blowup of the protons during a store. We will go through the theory and also show the measured results during the commissioning of this system. The system is currently operational and have stopped the beam blowups during a store.

  17. Religion and Aging in a Longitudinal Panel

    ERIC Educational Resources Information Center

    Blazer, Dan; Palmore, Erdman

    1976-01-01

    Analysis of religious activities and attitudes in a longitudinal panel of 272 community residents showed there were several significant and substantial correlations between religion and happiness, feelings of usefulness, and adjustment; these correlations also tended to be stronger for older persons and tended to increase over time. (Author)

  18. The Merits of Using Longitudinal Mediation

    ERIC Educational Resources Information Center

    Jose, Paul E.

    2016-01-01

    Many of the mediation analyses reported in the literature are based on concurrent or single-occasion data sets. The 2 overarching themes of the present article are: Results of concurrent mediations are inherently ambiguous, and researchers would be wise to conduct mediations on longitudinal data sets instead. An example included here demonstrates…

  19. Issues in Longitudinal Research on Motivation

    ERIC Educational Resources Information Center

    Stoel, Reinoud D.; Roeleveld, Jaap; Peetsma, Thea; van den Wittenboer, Godfried; Hox, Joop

    2006-01-01

    This paper discusses two methodological issues regarding the analysis of longitudinal data using structural equation modeling that emerged during the reconsideration of the analysis of a recent study on the relationship between academic motivation and language achievement in elementary education [Stoel R.D., Peetsma, T.T.D. and Roeleveld, J.…

  20. The Merits of Using Longitudinal Mediation

    ERIC Educational Resources Information Center

    Jose, Paul E.

    2016-01-01

    Many of the mediation analyses reported in the literature are based on concurrent or single-occasion data sets. The 2 overarching themes of the present article are: Results of concurrent mediations are inherently ambiguous, and researchers would be wise to conduct mediations on longitudinal data sets instead. An example included here demonstrates…

  1. MPCP Longitudinal Educational Growth Study Baseline Report

    ERIC Educational Resources Information Center

    Witte, John F.; Wolf, Patrick J.; Cowen, Joshua M.; Fleming, David J.; Lucas-McLean, Juanita

    2008-01-01

    This report focuses on the initial design, implementation and baseline results of the five-year Longitudinal Educational Growth Study (LEGS) of the Milwaukee Parental Choice Program (MPCP) being conducted by the School Choice Demonstration Project (SCDP). The LEGS will be the first evaluation of the participant effects of the MPCP using…

  2. Emotion Regulation and Childhood Aggression: Longitudinal Associations

    ERIC Educational Resources Information Center

    Roll, Judith; Koglin, Ute; Petermann, Franz

    2012-01-01

    Accumulating evidence suggests that emotion dysregulation is associated with psychopathology. This paper provides a review of recent longitudinal studies that investigate the relationship between emotion regulation and aggressive behavior in childhood age. While there is substantial evidence for assuming a close relation of emotion regulation and…

  3. Conducting Three-Level Longitudinal Analyses

    ERIC Educational Resources Information Center

    Peugh, James L.; Heck, Ronald H.

    2017-01-01

    Researchers in the field of early adolescence interested in quantifying the environmental influences on a response variable of interest over time would use cluster sampling (i.e., obtaining repeated measures from students nested within classrooms and/or schools) to obtain the needed sample size. The resulting longitudinal data would be nested at…

  4. Design and Implementation Issues in Longitudinal Research

    ERIC Educational Resources Information Center

    Ludlow, Larry H.; Pedulla, Joseph; Reagan, Emile Mitescu; Enterline, Sarah; Cannady, Mac; Chappe, Stephanie

    2011-01-01

    To meet demands for accountability, most schools and departments of education at institutions of higher education (IHEs) gather information on their current students and graduates. This paper describes issues to consider when designing a longitudinal data collection and management system, drawing on seven years' experience developing such a…

  5. Longitudinal Studies--Are They Worth It?

    ERIC Educational Resources Information Center

    Cowley, Judith

    A longitudinal study of otitis media in young children, begun in 1981, aimed to provide information on the incidence and prevalence of otitis media in young children in the Newcastle (England) region and to follow their academic progress. Subjects selected for the study were kindergartners in five schools and represented an ethnically homogeneous…

  6. An Early Intervention Project: A Longitudinal Look.

    ERIC Educational Resources Information Center

    Gordon, Ira J.

    This report describes the longitudinal research conducted in an early intervention program since 1966. The program is characterized by the use of paraprofessionals serving as home visitors and parent educators. Data collection has included measures of children's behavior and development, parent-child interactions, and parent variables such as…

  7. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Maneuverability § 23.145 Longitudinal control. (a) With the airplane as nearly as possible in trim at 1.3 VS1, it must be possible, at speeds below the trim speed, to pitch the nose downward so that the rate of increase in airspeed allows prompt acceleration to the trim speed with— (1) Maximum continuous power...

  8. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Maneuverability § 23.145 Longitudinal control. (a) With the airplane as nearly as possible in trim at 1.3 VS1, it must be possible, at speeds below the trim speed, to pitch the nose downward so that the rate of increase in airspeed allows prompt acceleration to the trim speed with— (1) Maximum continuous power...

  9. Longitudinal Predictors of High School Completion

    ERIC Educational Resources Information Center

    Barry, Melissa; Reschly, Amy L.

    2012-01-01

    This longitudinal study examined predictors of dropout assessed in elementary school. Student demographic data, achievement, attendance, and ratings of behavior from the Behavior Assessment System for Children were used to predict dropout and completion. Two models, which varied on student sex and race, predicted dropout at rates ranging from 75%…

  10. Longitudinal photosynthetic gradient in crust lichens' thalli.

    PubMed

    Wu, Li; Zhang, Gaoke; Lan, Shubin; Zhang, Delu; Hu, Chunxiang

    2014-05-01

    In order to evaluate the self-shading protection for inner photobionts, the photosynthetic activities of three crust lichens were detected using Microscope-Imaging-PAM. The false color images showed that longitudinal photosynthetic gradient was found in both the green algal lichen Placidium sp. and the cyanolichen Peltula sp. In longitudinal direction, all the four chlorophyll fluorescence parameters Fv/Fm, Yield, qP, and rETR gradually decreased with depth in the thalli of both of these two lichens. In Placidium sp., qN values decreased with depth, whereas an opposite trend was found in Peltula sp. However, no such photosynthetic heterogeneity was found in the thalli of Collema sp. in longitudinal direction. Microscope observation showed that photobiont cells are compactly arranged in Placidium sp. and Peltula sp. while loosely distributed in Collema sp. It was considered that the longitudinal photosynthetic heterogeneity was ascribed to the result of gradual decrease of incidence caused by the compact arrangement of photobiont cells in the thalli. The results indicate a good protection from the self-shading for the inner photobionts against high radiation in crust lichens.

  11. Emotion Regulation and Childhood Aggression: Longitudinal Associations

    ERIC Educational Resources Information Center

    Roll, Judith; Koglin, Ute; Petermann, Franz

    2012-01-01

    Accumulating evidence suggests that emotion dysregulation is associated with psychopathology. This paper provides a review of recent longitudinal studies that investigate the relationship between emotion regulation and aggressive behavior in childhood age. While there is substantial evidence for assuming a close relation of emotion regulation and…

  12. Investigating Ceiling Effects in Longitudinal Data Analysis

    ERIC Educational Resources Information Center

    Wang, Lijuan; Zhang, Zhiyong; McArdle, John J.; Salthouse, Timothy A.

    2008-01-01

    Score limitation at the top of a scale is commonly termed "ceiling effect." Ceiling effects can lead to serious artifactual parameter estimates in most data analysis. This study examines the consequences of ceiling effects in longitudinal data analysis and investigates several methods of dealing with ceiling effects through Monte Carlo simulations…

  13. Preschool Fears: Longitudinal Sequence and Cohort Changes.

    ERIC Educational Resources Information Center

    Draper, Thomas W.; James, Rebecca Smoak

    1985-01-01

    Using longitudinal data gathered between 1966 and 1981, parent-reported fears of 49 university preschool children were examined with particular attention given to age changes and sex differences. Categories of types of fears reported by Jersild and Holmes (1933) determined a substantial increase in preschool children's fears of the dark, being…

  14. The National Longitudinal Surveys Handbook. Revised.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center for Human Resource Research.

    Designed as a comprehensive guide to the National Longitudinal Surveys of Labor Market Experience (NLS), this handbook is intended for two major categories of readers. For persons who wish to ascertain whether their research interests can be served by the NLS data, the handbook can provide the detailed description of the objectives of the surveys,…

  15. Are Sibling Relationships Protective? A Longitudinal Study

    ERIC Educational Resources Information Center

    Gass, Krista; Jenkins, Jennifer; Dunn, Judy

    2007-01-01

    Background: Although the protective effects of familial and parental support have been studied extensively in the child psychopathology literature, few studies have explored the protective quality of positive sibling relationships. Methods: A two-wave longitudinal design was used to examine the protective effect of positive sibling relationships…

  16. Identified EM Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth, II; Saxton, Patrick

    2014-05-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After a number of custom rock experiments, two hypotheses were formed which could answer the EM wave model. The first hypothesis concerned a sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio transmission. Electron flow along fracture surfaces was determined to be inadequate in creating strong EM fields, because rock has a very high electrical resistance making it a high quality insulator. Penetrative flow could not be corroborated as well, because it was discovered that rock was absorbing and confining electrons to a very thin skin depth. Radio wave transmission and detection worked with every single test administered. This hypothesis was reviewed for propagating, long-wave generation with sufficient amplitude, and the capability of penetrating solid rock. Additionally, fracture spaces, either air or ion-filled, can facilitate this concept from great depths and allow for surficial detection. A few propagating precursor signals have been detected in the field occurring with associated phases using custom-built loop antennae. Field testing was conducted in Southern California from 2006-2011, and outside the NE Texas town of Timpson in February, 2013. The antennae have mobility and observations were noted for

  17. Titan's Longitudinal Dunes in the Lab.

    NASA Astrophysics Data System (ADS)

    Reffet, Erwan; Courrech du Pont, S.; Hersen, P.; Douady, S.; Radebaugh, J.; Lorenz, R.; Lunine, J.; Boubin, G.; Fulchignoni, M.

    2007-10-01

    Cassini Radar observations of Titan's surface have revealed various landscapes. In particular, flybys probing Titan's equator unveiled linear features [1], which are morphologically similar to longitudinal dunes [2,3]. They appear pervasive in the range +-30° in latitude and could cover up to 20% of Titan's surface [4]. Their characteristics in term of width, length and spacing [1,4,5], or height and slope [6] are comparable to dunes of the Namib Desert [2]. On Earth, longitudinal dunes are the most commonly encountered dune and are observed in regions where the wind regime is composed of two main directions, the dunes orientation giving the mean sand transport. While terrestrial dunes are mostly formed by quartz sand grains, Titan's dunes are likely to be composed of hydrocarbon particulates [7]. Despite their different compositions, their morphological resemblances suggest similar processes of formation. Thus studying the formation of such structures could help to constrain models of Titan's winds [8]. However, formation of longitudinal dunes or even more generally longitudinal bedforms [9] have rarely been observed or reproduced in controlled conditions. Underwater experiments, in which sand transport timescale and lengthscale are decreased, have been used to successfully reproduce the dynamics of barchan dunes [10]. We show here how it is possible to explore the morphogenesis of longitudinal dunes using such a method combined with a numerical model. References: [1] Boubin et al. DPS 2005. [2] Lorenz et al. LPSC 2006. [3] Lorenz et al. Science 2006. [4] Radebaugh et al. Icarus (in revision). [5] Radebaugh et al. LPSC 2006. [6] Kirk et al. LPSC 2005. [7] Soderblom et al. P&SS (in press). [8] Tokano et al. Icarus 2002. [9] Rubin et al. Science 1987. [10] Hersen et al. PRL, 2003.

  18. Using the Longitudinal Study as a Central Teaching Focus.

    ERIC Educational Resources Information Center

    Demchik, Michael J.

    1999-01-01

    Argues that treatment of one investigative longitudinal topic from start to finish in a high school biology class can illustrate many major ideas and concepts. Discusses ways to use various longitudinal studies of plant growth with General Biology classes. (WRM)

  19. 115. DETAILS OF REINFORCEMENT: TYPICAL CROSSSECTION, LONGITUDINAL BRACE OF CENTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    115. DETAILS OF REINFORCEMENT: TYPICAL CROSS-SECTION, LONGITUDINAL BRACE OF CENTER PILES, OUTSIDE LONGITUDINAL GIRDER Sheet 6 of 9 (#3257) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  20. Longitudinal Multitrait-Multimethod Models for Developmental Research

    ERIC Educational Resources Information Center

    Grimm, Kevin J.; Pianta, Robert C.; Konold, Timothy

    2009-01-01

    Multitrait-multimethod (MTMM) confirmatory factor models were combined with longitudinal structural equation models to examine trait and method stability over time. A longitudinal correlated-trait correlated-method (CT-CM) model allowed for the study of trait and method variance in observed scores over time. Longitudinal measurement invariance was…

  1. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static longitudinal stability. 29.173 Section 29.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Static longitudinal stability. (a) The longitudinal control must be designed so that a rearward...

  2. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Longitudinal static compressive strength. 238.405... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an effective... shall resist a minimum longitudinal static compressive force of 2,100,000 pounds without...

  3. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 29.173 Section 29.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Static longitudinal stability. (a) The longitudinal control must be designed so that a rearward...

  4. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Demonstration of static longitudinal stability. 23.175 Section 23.175 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Flight Stability § 23.175 Demonstration of static longitudinal stability. Static longitudinal...

  5. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Demonstration of static longitudinal stability. 23.175 Section 23.175 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Flight Stability § 23.175 Demonstration of static longitudinal stability. Static longitudinal...

  6. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Longitudinal static compressive strength. 238.405... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an effective... shall resist a minimum longitudinal static compressive force of 2,100,000 pounds without...

  7. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Longitudinal static compressive strength. 238.405... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an effective... shall resist a minimum longitudinal static compressive force of 2,100,000 pounds without...

  8. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Longitudinal static compressive strength. 238.405... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an effective... shall resist a minimum longitudinal static compressive force of 2,100,000 pounds without...

  9. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Demonstration of static longitudinal stability. 23.175 Section 23.175 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Flight Stability § 23.175 Demonstration of static longitudinal stability. Static longitudinal...

  10. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static longitudinal stability. 29.173 Section 29.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Static longitudinal stability. (a) The longitudinal control must be designed so that a rearward...

  11. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Demonstration of static longitudinal stability. 23.175 Section 23.175 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Flight Stability § 23.175 Demonstration of static longitudinal stability. Static longitudinal...

  12. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Longitudinal static compressive strength. 238.405... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an effective... shall resist a minimum longitudinal static compressive force of 2,100,000 pounds without...

  13. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Demonstration of static longitudinal stability. 23.175 Section 23.175 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Flight Stability § 23.175 Demonstration of static longitudinal stability. Static longitudinal...

  14. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static longitudinal stability. 29.173 Section 29.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Static longitudinal stability. (a) The longitudinal control must be designed so that a rearward...

  15. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static longitudinal stability. 29.173 Section 29.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Static longitudinal stability. (a) The longitudinal control must be designed so that a rearward...

  16. 46 CFR 154.176 - Longitudinal contiguous hull structure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet...

  17. Diseno de una Actividad de Aprendizaje Basada en la Argumentacion Dialogica en un curso Virtual de Biotecnologia y su Incidencia en el Desarrollo de Competencias Cientificas

    NASA Astrophysics Data System (ADS)

    Ortiz Benavides, Fedra Lorena

    El proposito de la investigacion fue evaluar la efectividad de una actividad de aprendizaje basado en la argumentacion dialogica en linea y su incidencia en el desarrollo de competencias cientificas. Se fundamenta en la teoria del aprendizaje socio cultural de Vigotsky (1984), los principios del diseno instruccional de la cognicion situada por Hung y Der-Thang (2001) y como estrategia se aplico la argumentacion dialogica utilizando el Modelo Argumentativo de Toulmin MAT (1984). El diseno experimental comparo dos grupos de estudiantes A y B en el curso virtual de Biotecnologia. El grupo A (experimental) desarrollo la discusion a partir de la estrategia disenada para este estudio y el grupo B (control) realizo la discusion desde las actividades tradicionales. El desarrollo de la competencia argumentativa se valoro con el instrumento de evaluacion para argumentacion dialogica en linea propuesta por Clark y Sampson (2008). La evaluacion de las competencias cientificas se realizo a partir de una postprueba. Los datos fueron analizados con pruebas estadisticas no parametricas. Los resultados de la investigacion, indicaron diferencias significativas en el nivel de la competencia argumental en el grupo experimental en comparacion al grupo control. Igualmente se demostro que existe una relacion positiva entre el nivel de desarrollo de la competencia argumentativa y el nivel de desarrollo de las competencias cientificas.

  18. Discussions about the Nature of Science in a Course on the History of Astronomy. (Spanish Title: Discusiones sobre la Naturaleza de la Ciencia en un Curso sobre Historia de la Astronomía.) Discussões sobre a Natureza da Ciência em um Curso sobre a História da Astronomia

    NASA Astrophysics Data System (ADS)

    Pires de Andrade, Victória Flório; L'Astorina, Bruno

    2010-07-01

    There are an increasing number of researches in science education that affirm the importance of discussions on the "nature of science" in basic education level as well as in teacher training. The history of science applied to education is a way to contextualize epistemological discussions, allowing both the understanding of scientific content and learning about science concepts. We present some reasonably consensual definitions on the nature of science that have been widely discussed by the academic community. We show also some episodes in the history of astronomy which can lead to discussions involving some aspects of the nature of science, and how they can do it. Hay un número creciente de investigaciones en la enseñanza de las ciencias que afirman la importancia de debates sobre la "naturaleza de la ciencia" en la educación básica y formación del profesorado. La historia de la ciencia aplicada a la educación es una manera de contextualizar los debates de la epistemología, lo que permite tanto la comprensión de los contenidos científicos como el aprendizaje de conceptos científicos. En esto trabajo, presentamos algunas definiciones bastante consensuales sobre la naturaleza de la ciencia que han sido ampliamente discutidas por la comunidad académica y mostramos cómo algunos episodios en la historia de la astronomía pueden llevar a discusiones sobre algunos aspectos de la naturaleza de la ciencia. Há um número crescente de pesquisas na área de ensino de ciências que afirmam a importância de discussões sobre a "natureza da ciência" na educação básica e na formação de professores. A história da ciência aplicada ao ensino é uma maneira de contextualizar discussões epistemológicas, permitindo tanto a compreensão de conteúdos científicos quanto o aprendizado de noções sobre as ciências. Neste trabalho apresentamos algumas definições razoavelmente consensuais sobre a natureza da ciência que foram amplamente discutidas pela comunidade acadêmica e mostramos como alguns episódios da história da astronomia podem levar a discussões envolvendo alguns dos aspectos da natureza da ciência.

  19. A 2-D numerical simulation study on longitudinal solute transport and longitudinal dispersion coefficient

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    2011-07-01

    The longitudinal dispersion coefficient, DL, is a fundamental parameter of longitudinal solute transport models: the advection-dispersion (AD) model and various deadzone models. Since DL cannot be measured directly, and since its calibration using tracer test data is quite expensive and not always available, researchers have developed various methods, theoretical or empirical, for estimating DL by easier available cross-sectional hydraulic measurements (i.e., the transverse velocity profile, etc.). However, for known and unknown reasons, DL cannot be satisfactorily predicted using these theoretical/empirical formulae. Either there is very large prediction error for theoretical methods, or there is a lack of generality for the empirical formulae. Here, numerical experiments using Mike21, a software package that implements one of the most rigorous two-dimensional hydrodynamic and solute transport equations, for longitudinal solute transport in hypothetical streams, are presented. An analysis of the evolution of simulated solute clouds indicates that the two fundamental assumptions in Fischer's longitudinal transport analysis may be not reasonable. The transverse solute concentration distribution, and hence the longitudinal transport appears to be controlled by a dimensionless number ?, where Q is the average volumetric flowrate, Dt is a cross-sectional average transverse dispersion coefficient, and W is channel flow width. A simple empirical ? relationship may be established. Analysis and a revision of Fischer's theoretical formula suggest that ɛ influences the efficiency of transverse mixing and hence has restraining effect on longitudinal spreading. The findings presented here would improve and expand our understanding of longitudinal solute transport in open channel flow.

  20. Longitudinal Trajectories of Cigarette Smoking Following Rape

    PubMed Central

    Amstadter, Ananda B.; Resnick, Heidi S.; Nugent, Nicole R.; Acierno, Ron; Rheingold, Alyssa A.; Minhinnett, Robin; Kilpatrick, Dean G.

    2009-01-01

    Although prior research has identified increases in cigarette smoking following trauma exposure, no studies have examined longitudinal trajectories of smoking following rape. The present investigation identifies and characterizes longitudinal (< 3 months, 3-6 months, and > 6 months post-assault) trajectories of smoking (N = 152) following a rape in a sample of 268 sexual assault victims participating in a forensic medical exam. Further, we examine acute predictors of subsequent smoking trajectories. Of participants endorsing smoking post-rape, a two-class solution was identified, with the majority of participants (74.6%) evidencing moderate smoking with a slight decrease over time and remaining participants showing heavy smoking with a slight increase over time. Having sustained an injury, minority status, and post-exam distress all predicted subsequent smoking trajectory. PMID:19370699

  1. Longitudinal variations of the equatorial electojet

    NASA Astrophysics Data System (ADS)

    Shume, Esayas

    We have utilized a three dimensional electrostatic potential model to explain the longitudinal variations of the equatorial electrojet. The model runs were constrained by net H component magnetic field measurements from three equatorial stations, namely, Huancayo (Peru) 12.05 S, 284.67 E; Addis Ababa (Ethiopia) 9.8 N, 38.8 E; Tirunelveli (India) 8.42 N, 77.48 E. The model runs were done in an iterative fashion until the computed and measured H component magnetic field values come into a close agreement. The physical mechanisms for the longitudinal variations of the equatorial electrojet were inferred by comparing and contrasting the resulting computed vertical polarization electric field (which drives the equatorial electrojet), and zonal current density profiles for the three stations mentioned above.

  2. Linac Coherent Light Source Longitudinal Feedback Model

    SciTech Connect

    Wu, Juhao; Emma, P.; Hendrickson, L.; /SLAC

    2005-06-15

    The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, it is critical to preserve the high quality of the electron beam during acceleration and compression. The peak current and final energy are very sensitive to system jitter. To minimize this sensitivity, a longitudinal feedback system on the bunch length and energy is required, together with other diagnostics and feedback systems (e.g., on transverse phase space). Here, we describe a simulation framework, which includes a realistic jitter model for the LCLS accelerator system, the RF acceleration, structure wakefield, and second order optics. Simulation results show that to meet the tight requirements set by the FEL, such a longitudinal feedback system is mandatory.

  3. Left ventricular longitudinal strain in soccer referees.

    PubMed

    Gianturco, Luigi; Bodini, Bruno; Gianturco, Vincenzo; Lippo, Giuseppina; Solbiati, Agnese; Turiel, Maurizio

    2017-02-09

    Along the years, the analysis of soccer referees perfomance has interested the experts and we can find several types of studies in literature using in particular cardiac imaging. The aim of this retrospective study was to observe relationship between VO2max uptake and some conventional and not-conventional echocardiographic parameters. In order to perform this evaluation, we have enrolled 20 referees, belonging to Italian Soccer Referees' Association and we have investigated cardiovascular profile of them. We found a strong direct relationship between VO2max and global longitudinal strain of left ventricle assessed by means of speckle tracking echocardiographic analysis (R2=0.8464). The most common classic echocardiographic indexes have showed mild relations (respectively, VO2max vs EF: R2=0.4444; VO2max vs LV indexed mass: R2=0.2268). Therefore, our study suggests that longitudinal strain could be proposed as a specific echocardiographic parameter to evaluate the soccer referees performance.

  4. A longitudinal analysis of teenage drinking patterns.

    PubMed

    Shahtahmasebi, Said; Berridge, Damon

    2009-01-01

    This paper examines the multinomial recurrent outcome 'teenage drinking' within a statistical modeling paradigm. The proposed statistical modeling relates drinking to a set of explanatory variables, which include subjective as well as objective measures. In order to assess the degree to which explanatory variables influence smoking, an adequate statistical model must handle the possibility that substantial variation between respondents will be due to omitted variables, multicollinearity and past behavior. To address these issues, longitudinal data using appropriate statistical modeling are essential. In this paper we demonstrate the application of appropriate longitudinal modeling using data from the Yorkshire (UK) Health Related Behavior Questionnaire. The results suggest there may be substantial heterogeneity due to omitted variables in the data and complex inter-relationships between observed explanatory variables. For example, social cultures of drinking and parental involvement appear to influence heavy drinking and drug use.

  5. Left ventricular longitudinal strain in soccer referees

    PubMed Central

    Gianturco, Luigi; Bodini, Bruno; Gianturco, Vincenzo; Lippo, Giuseppina; Solbiati, Agnese; Turiel, Maurizio

    2017-01-01

    Along the years, the analysis of soccer referees perfomance has interested the experts and we can find several types of studies in literature using in particular cardiac imaging. The aim of this retrospective study was to observe relationship between VO2max uptake and some conventional and not-conventional echocardiographic parameters. In order to perform this evaluation, we have enrolled 20 referees, belonging to Italian Soccer Referees' Association and we have investigated cardiovascular profile of them. We found a strong direct relationship between VO2max and global longitudinal strain of left ventricle assessed by means of speckle tracking echocardiographic analysis (R2=0.8464). The most common classic echocardiographic indexes have showed mild relations (respectively, VO2max vs EF: R2=0.4444; VO2max vs LV indexed mass: R2=0.2268). Therefore, our study suggests that longitudinal strain could be proposed as a specific echocardiographic parameter to evaluate the soccer referees performance. PMID:28199991

  6. Longitudinal multiple sclerosis lesion segmentation data resource.

    PubMed

    Carass, Aaron; Roy, Snehashis; Jog, Amod; Cuzzocreo, Jennifer L; Magrath, Elizabeth; Gherman, Adrian; Button, Julia; Nguyen, James; Bazin, Pierre-Louis; Calabresi, Peter A; Crainiceanu, Ciprian M; Ellingsen, Lotta M; Reich, Daniel S; Prince, Jerry L; Pham, Dzung L

    2017-06-01

    The data presented in this article is related to the research article entitled "Longitudinal multiple sclerosis lesion segmentation: Resource and challenge" (Carass et al., 2017) [1]. In conjunction with the 2015 International Symposium on Biomedical Imaging, we organized a longitudinal multiple sclerosis (MS) lesion segmentation challenge providing training and test data to registered participants. The training data consists of five subjects with a mean of 4.4 (±0.55) time-points, and test data of fourteen subjects with a mean of 4.4 (±0.67) time-points. All 82 data sets had the white matter lesions associated with multiple sclerosis delineated by two human expert raters. The training data including multi-modal scans and manually delineated lesion masks is available for download. In addition, the testing data is also being made available in conjunction with a website for evaluating the automated analysis of the testing data.

  7. A Sparse Bayesian Learning Algorithm for Longitudinal Image Data.

    PubMed

    Sabuncu, Mert R

    2015-10-01

    Longitudinal imaging studies, where serial (multiple) scans are collected on each individual, are becoming increasingly widespread. The field of machine learning has in general neglected the longitudinal design, since many algorithms are built on the assumption that each datapoint is an independent sample. Thus, the application of general purpose machine learning tools to longitudinal image data can be sub-optimal. Here, we present a novel machine learning algorithm designed to handle longitudinal image datasets. Our approach builds on a sparse Bayesian image-based prediction algorithm. Our empirical results demonstrate that the proposed method can offer a significant boost in prediction performance with longitudinal clinical data.

  8. Nonlinear longitudinal control of a supermaneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Snell, Anthony; Enns, Dale F.

    1989-01-01

    A technique is described which can be used for design of feedback controllers for high-performance aircraft operating in flight conditions in which nonlinearities significantly affect performance. Designs are performed on a mathematical model of the longitudinal dynamics of a hypothetical aircraft similar to proposed supermaneuverable flight test vehicles. Nonlinear controller designs are performed using truncated solutions of the Hamilton-Jacobi-Bellman equation. Preliminary results show that the method yields promising results.

  9. Nonlinear longitudinal control of a supermaneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Snell, Anthony; Enns, Dale F.

    1989-01-01

    A technique is described which can be used for design of feedback controllers for high-performance aircraft operating in flight conditions in which nonlinearities significantly affect performance. Designs are performed on a mathematical model of the longitudinal dynamics of a hypothetical aircraft similar to proposed supermaneuverable flight test vehicles. Nonlinear controller designs are performed using truncated solutions of the Hamilton-Jacobi-Bellman equation. Preliminary results show that the method yields promising results.

  10. Marginal longitudinal semiparametric regression via penalized splines

    PubMed Central

    Kadiri, M. Al; Carroll, R.J.; Wand, M.P.

    2010-01-01

    We study the marginal longitudinal nonparametric regression problem and some of its semiparametric extensions. We point out that, while several elaborate proposals for efficient estimation have been proposed, a relative simple and straightforward one, based on penalized splines, has not. After describing our approach, we then explain how Gibbs sampling and the BUGS software can be used to achieve quick and effective implementation. Illustrations are provided for nonparametric regression and additive models. PMID:21037941

  11. Moving Block Bootstrap for Analyzing Longitudinal Data

    PubMed Central

    Ju, Hyunsu

    2015-01-01

    In a longitudinal study subjects are followed over time. I focus on a case where the number of replications over time is large relative to the number of subjects in the study. I investigate the use of moving block bootstrap methods for analyzing such data. Asymptotic properties of the bootstrap methods in this setting are derived. The effectiveness of these resampling methods is also demonstrated through a simulation study. PMID:26023251

  12. Anterior longitudinal aortotomy in aortic valve replacement.

    PubMed

    Matsuzaki, Kanji; Kudo, Yohei; Ikeda, Akihiko; Konishi, Taisuke; Jikuya, Tomoaki

    2016-02-01

    We adopted an anterior longitudinal aortotomy in some cases of aortic valve replacement (AVR), and report them here. The potential of this method is also discussed. We analyzed the data on 24 patients (75.5 ± 7.8 years of age) who had undergone AVR through anterior longitudinal aortotomy. The indications for surgery were prosthetic valve complication in 5 patients, aortic stenosis (AS) with left ventricular outflow tract stenosis (LVOTS) in 16 patients, and aortic regurgitation with moderately dilated ascending aorta in 3 patients. The Konno procedure was performed in 6 cases with small aortic annuli. A longitudinal aortotomy was made at the aortic root along the left side of the right coronary ostium, and extended beyond the right coronary annulus to the interventricular septum as needed. Bioprostheses (21.1 ± 1.7 mm) were used in 23 patients and a 21-mm mechanical valve for one (a 59-year-old man). One high-risk patient died of low output syndrome, leading to a mortality rate of 4.2 %. All other patients recovered well, though atrioventricular block occurred in 2 cases. Anterior longitudinal aortotomy provides a good field of vision at the aortic annulus and the flexibility to develop into anterior annular enlargement. Major indications for this approach are small sino-tubular junction and very small aortic annulus. This approach could be an attractive option in AVR for cases of AS with small aortic annuli and LVOTS. It could also be useful for AVR cases with moderately dilated ascending aorta requiring aortoplasty.

  13. Predictors of Transfer Adjustment: A Longitudinal Study.

    DTIC Science & Technology

    1985-01-01

    Department of Psychology . : PREDICTORS OF TRANSFER AIIJUSTNEN: . A LONGITUDIN4AL STUDY"- Jaues B. Shaw Cynthia D. Fisher and Richard W. Woodman...1985 Acssa o NTIS GRA&I TR-ONR-7 DTIC TAB Unannounced E Just ification Distribution/ Department of Psychology Availability Codes Department of...PROJECT. TASKAREA & WORK UNIT NUMIBERS Departments of Management and Psychology 62763 N Texas.A&M University RF 63521 College Station, TX 77843 RF

  14. RADON reconstruction in longitudinal phase space

    SciTech Connect

    Mane, V.; Peggs, S.; Wei, J.

    1997-07-01

    Longitudinal particle motion in circular accelerators is typically monitoring by one dimensional (1-D) profiles. Adiabatic particle motion in two dimensional (2-D) phase space can be reconstructed with tomographic techniques, using 1-D profiles. A computer program RADON has been developed in C++ to process digitized mountain range data and perform the phase space reconstruction for the AGS, and later for Relativistic Heavy Ion Collider (RHIC).

  15. CLADA: cortical longitudinal atrophy detection algorithm.

    PubMed

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2011-01-01

    Measurement of changes in brain cortical thickness is useful for the assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for the measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower resolution images, such as the MRIs with 1×1×5 mm(3) voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm(3) isotropic voxels and 0.77% for images with 1×1×5 mm(3) voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post-mortem tissue. CLADA's sensitivity for correctly detecting at least 0.1mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation=0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images.

  16. CLADA: Cortical Longitudinal Atrophy Detection Algorithm

    PubMed Central

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2010-01-01

    Measurement of changes in brain cortical thickness is useful for assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower-resolution images, such as the MRIs with 1×1×5mm3 voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm3 isotropic voxels and 0.77% for images with 1×1×5 mm3 voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post- mortem tissue. CLADA’s sensitivity for correctly detecting at least 0.1 mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation = 0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images. PMID:20674750

  17. Moving Block Bootstrap for Analyzing Longitudinal Data.

    PubMed

    Ju, Hyunsu

    In a longitudinal study subjects are followed over time. I focus on a case where the number of replications over time is large relative to the number of subjects in the study. I investigate the use of moving block bootstrap methods for analyzing such data. Asymptotic properties of the bootstrap methods in this setting are derived. The effectiveness of these resampling methods is also demonstrated through a simulation study.

  18. PREPROCESSING MAGNETIC FIELDS WITH CHROMOSPHERIC LONGITUDINAL FIELDS

    SciTech Connect

    Yamamoto, Tetsuya T.; Kusano, K.

    2012-06-20

    Nonlinear force-free field (NLFFF) extrapolation is a powerful tool for the modeling of the magnetic field in the solar corona. However, since the photospheric magnetic field does not in general satisfy the force-free condition, some kind of processing is required to assimilate data into the model. In this paper, we report the results of new preprocessing for the NLFFF extrapolation. Through this preprocessing, we expect to obtain magnetic field data similar to those in the chromosphere. In our preprocessing, we add a new term concerning chromospheric longitudinal fields into the optimization function proposed by Wiegelmann et al. We perform a parameter survey of six free parameters to find minimum force- and torque-freeness with the simulated-annealing method. Analyzed data are a photospheric vector magnetogram of AR 10953 observed with the Hinode spectropolarimeter and a chromospheric longitudinal magnetogram observed with SOLIS spectropolarimeter. It is found that some preprocessed fields show the smallest force- and torque-freeness and are very similar to the chromospheric longitudinal fields. On the other hand, other preprocessed fields show noisy maps, although the force- and torque-freeness are of the same order. By analyzing preprocessed noisy maps in the wave number space, we found that small and large wave number components balance out on the force-free index. We also discuss our iteration limit of the simulated-annealing method and magnetic structure broadening in the chromosphere.

  19. Longitudinal analysis of mouse SDOCT volumes

    NASA Astrophysics Data System (ADS)

    Antony, Bhavna J.; Carass, Aaron; Lang, Andrew; Kim, Byung-Jin; Zack, Donald J.; Prince, Jerry L.

    2017-03-01

    Spectral-domain optical coherence tomography (SDOCT), in addition to its routine clinical use in the diagnosis of ocular diseases, has begun to fund increasing use in animal studies. Animal models are frequently used to study disease mechanisms as well as to test drug efficacy. In particular, SDOCT provides the ability to study animals longitudinally and non-invasively over long periods of time. However, the lack of anatomical landmarks makes the longitudinal scan acquisition prone to inconsistencies in orientation. Here, we propose a method for the automated registration of mouse SDOCT volumes. The method begins by accurately segmenting the blood vessels and the optic nerve head region in the scans using a pixel classification approach. The segmented vessel maps from follow-up scans were registered using an iterative closest point (ICP) algorithm to the baseline scan to allow for the accurate longitudinal tracking of thickness changes. Eighteen SDOCT volumes from a light damage model study were used to train a random forest utilized in the pixel classification step. The area under the curve (AUC) in a leave-one-out study for the retinal blood vessels and the optic nerve head (ONH) was found to be 0.93 and 0.98, respectively. The complete proposed framework, the retinal vasculature segmentation and the ICP registration, was applied to a secondary set of scans obtained from a light damage model. A qualitative assessment of the registration showed no registration failures.

  20. Partly conditional survival models for longitudinal data.

    PubMed

    Zheng, Yingye; Heagerty, Patrick J

    2005-06-01

    It is common in longitudinal studies to collect information on the time until a key clinical event, such as death, and to measure markers of patient health at multiple follow-up times. One approach to the joint analysis of survival and repeated measures data adopts a time-varying covariate regression model for the event time hazard. Using this standard approach, the instantaneous risk of death at time t is specified as a possibly semi-parametric function of covariate information that has accrued through time t. In this manuscript, we decouple the time scale for modeling the hazard from the time scale for accrual of available longitudinal covariate information. Specifically, we propose a class of models that condition on the covariate information through time s and then specifies the conditional hazard for times t, where t > s. Our approach parallels the "partly conditional" models proposed by Pepe and Couper (1997, Journal of the American Statistical Association 92, 991-998) for pure repeated measures applications. Estimation is based on the use of estimating equations applied to clusters of data formed through the creation of derived survival times that measure the time from measurement of covariates to the end of follow-up. Patient follow-up may be terminated either by the occurrence of the event or by censoring. The proposed methods allow a flexible characterization of the association between a longitudinal covariate process and a survival time, and facilitate the direct prediction of survival probabilities in the time-varying covariate setting.

  1. Longitudinal Electroproduction of Charged Pions from

    SciTech Connect

    David Gaskell; Abdellah Ahmidouch; Pawel Ambrozewicz; H. Anklin; John Arrington; K. Assamagan; Steven Avery; Kevin Bailey; Oliver K. Baker; Shelton Beedoe; Elizabeth Beise; Herbert Breuer; D. S. Brown; Roger Carlini; Jinseok Cha; Nicholas Chant; Anthony Cowley; Samuel Danagoulian; D. De Schepper; Jim Dunne; Dipangkar Dutta; Rolf Ent; Liping Gan; Ashot Gasparian; Donald Geesaman; Ron Gilman; Charles Glashausser; Paul Gueye; M. Harvey; O. Hashimoto; Wendy Hinton; G. Hofman; Ceasar Jackson; Hal Jackson; Cynthia Keppel; Ed Kinney; Doug Koltenuk; G. Kyle; Allison Lung; David Mack; D. McKee; Joseph Mitchell; Hamlet Mkrtchyan; B. Mueller; Gabriel Niculescu; Ioana Niculescu; Tom O'Neill; V. Papavassiliou; Dave Potterveld; Juerg Reinhold; Philip Roos; Reyad Sawafta; Ralph Segel; Stepan Stepanyan; Vardan Tadevosyan; T. Takahashi; Liguang Tang; B. Terburg; D. Van Westrum; J. Volmer; T. P. Welch; Stephen Wood; Lulin Yuan; Ben Zeidman; Beni Zihlmann

    2001-11-12

    Separated longitudinal and transverse cross sections for charged pion electroproduction from {sup 1}H, {sup 2}H, and {sup 3}He were measured at Q{sup 2} = 0.4 (GeV/c){sup 2} for two values of the invariant mass, {bar W} = 1.15 GeV and {bar W} = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil momenta significantly above the Fermi surface. The longitudinal cross section, if dominated by the pion-pole process, should be sensitive to nuclear pion currents. Comparisons of the longitudinal cross section target ratios to a quasifree calculation reveal a significant suppression in {sup 3>}He at {bar W} = 1.60 GeV. The {bar W} = 1.15 GeV results are consistent with simple estimates of the effect of nuclear pion currents, but are also consistent with pure quasifree production.

  2. Longitudinal wakefield for an axisymmetric collimator

    SciTech Connect

    Blednykh A.; Krinsky, S.

    2012-05-25

    We consider the longitudinal point-charge wakefield, w(s), for an axisymmetric collimator having inner radius b, outer radius d, inner length g, and taper length L. The taper angle {alpha} is defined by tan {alpha} = (d-b)/L. Using the electromagnetic simulation code ECHO, we explore the dependence of the wakefield on a collimator's geometric parameters over a wide range of profiles: from small-angle tapers to step-function transitions. The point-charge wakefield is determined using an approximation introduced by Podobedov and Stupakov. We have found it useful to exhibit the wakefield as a function of the scaled variable s/d{alpha}. For small taper angles, our results illustrate the satisfaction of the longitudinal scaling found by Stupakov, Bane, and Zagorodnov; and for larger taper angles, the breaking of this longitudinal scaling is clearly depicted. The use of the scaled variable s/d{alpha} turns out to be especially well suited to describing the wakefield for a collimator with step-function profile ({alpha} = {pi}/2).

  3. Longitudinal analysis of attitudes toward wolves.

    PubMed

    Treves, Adrian; Naughton-Treves, Lisa; Shelley, Victoria

    2013-04-01

    Understanding individual attitudes and how these predict overt opposition to predator conservation or direct, covert action against predators will help to recover and maintain them. Studies of attitudes toward wild animals rely primarily on samples of individuals at a single time point. We examined longitudinal change in individuals' attitudes toward gray wolves (Canis lupus). In the contiguous United States, amidst persistent controversy and opposition, abundances of gray wolves are at their highest in 60 years. We used mailed surveys to sample 1892 residents of Wisconsin in 2001 or 2004 and then resampled 656 of these individuals who resided in wolf range in 2009. Our study spanned a period of policy shifts and increasing wolf abundance. Over time, the 656 respondents increased agreement with statements reflecting fear of wolves, the belief that wolves compete with hunters for deer (Odocoileus virginianus), and inclination to poach a wolf. Endorsement of lethal control of wolves by the state and public hunting of wolves also increased. Neither the time span over which respondents reported exposure to wolves locally nor self-reported losses of domestic animals to wolves correlated with changes in attitude. We predict future increases in legal and illegal killing of wolves that may reduce their abundance in Wisconsin unless interventions are implemented to improve attitudes and behavior toward wolves. To assess whether interventions change attitudes, longitudinal studies like ours are needed. Análisis Longitudinal de las Actitudes Hacia Lobos. © 2013 Society for Conservation Biology.

  4. Material deprivation and health: a longitudinal study.

    PubMed

    Tøge, Anne Grete; Bell, Ruth

    2016-08-08

    Does material deprivation affect the consequences of ill health? Answering this question requires that we move beyond the effects of income. Longitudinal data on material deprivation, longstanding illness and limiting longstanding illness enables investigations of the effects of material deprivation on risk of limiting longstanding illness. This study investigates whether a shift from affording to not affording a car predicts the probability of limiting longstanding ill (LLSI). The 2008-2011 longitudinal panel of Statistics on Income, Social Inclusion and Living Conditions (EU-SILC) is utilised. Longitudinal fixed effects logit models are applied, using LLSI as dependent variable. Transition from affording a car to not affording a car is used as a proxy for material deprivation. All models are controlled for whether the person becomes longstanding ill (LSI) as well as other time-variant covariates that could affect the results. The analysis shows a statistically significant increased odds ratio of LLSI when individuals no longer can afford a car, after controlling for confounders and LSI in the previous year (1.129, CI = 1.022-1.248). However, when restricting the sample to observations where respondents report longstanding illness the results are no longer significant (1.032, CI = 0.910-1.171). The results indicate an individual level effect of material deprivation on LLSI, suggesting that material resources can affect the consequences of ill health.

  5. Quality of reporting of observational longitudinal research.

    PubMed

    Tooth, Leigh; Ware, Robert; Bain, Chris; Purdie, David M; Dobson, Annette

    2005-02-01

    Observational longitudinal research is particularly useful for assessing etiology and prognosis and for providing evidence for clinical decision making. However, there are no structured reporting requirements for studies of this design to assist authors, editors, and readers. The authors developed and tested a checklist of criteria related to threats to the internal and external validity of observational longitudinal studies. The checklist criteria concerned recruitment, data collection, biases, and data analysis and descriptive issues relevant to study rationale, study population, and generalizability. Two raters independently assessed 49 randomly selected articles describing stroke research published from 1999 to 2003 in six journals: American Journal of Epidemiology, Journal of Epidemiology and Community Health, Stroke, Annals of Neurology, Archives of Physical Medicine and Rehabilitation, and American Journal of Physical Medicine and Rehabilitation. On average, 17 of the 33 checklist criteria were reported. Criteria describing the study design were better reported than those related to internal validity. No relation was found between study type (etiologic or prognostic) or word count and quality of reporting. A flow diagram for summarizing participant flow through a study was developed. Editors and authors should consider using a checklist and flow diagram when reporting on observational longitudinal research.

  6. Magnetization Transfer Induced Biexponential Longitudinal Relaxation

    PubMed Central

    Prantner, Andrew M.; Bretthorst, G. Larry; Neil, Jeffrey J.; Garbow, Joel R.; Ackerman, Joseph J.H.

    2009-01-01

    Longitudinal relaxation of brain water 1H magnetization in mammalian brain in vivo is typically analyzed on a per voxel basis using a monoexponential model, thereby assigning a single relaxation time constant to all 1H magnetization within a given voxel. This approach was tested by obtaining inversion recovery data from grey matter of rats at 64 exponentially-spaced recovery times. Using Bayesian probability for model selection, brain water data were best represented by a biexponential function characterized by fast and slow relaxation components. At 4.7 T, the amplitude fraction of the rapidly relaxing component is 3.4 ± 0.7 % with a rate constant of 44 ± 12 s-1 (mean ± SD; 174 voxels from 4 rats). The rate constant of the slow relaxing component is 0.66 ± 0.04 s-1. At 11.7 T, the corresponding values are 6.9 ± 0.9 %, 19 ± 5 s-1, and 0.48 ± 0.02 s-1 (151 voxels from 4 rats). Several putative mechanisms for biexponential relaxation behavior were evaluated, and magnetization transfer between bulk water protons and non-aqueous protons was determined to be the source of biexponential longitudinal relaxation. MR methods requiring accurate quantification of longitudinal relaxation may need to take this effect explicitly into account. PMID:18759367

  7. Nucleon Spin Structure: Longitudinal and Transverse

    SciTech Connect

    Jian-Ping Chen

    2011-02-01

    Inclusive Deep-Inelastic Scattering (DIS) experiments have provided us with the most extensive information on the unpolarized and longitudinal polarized parton (quark and gluon) distributions in the nucleon. It has becoming clear that transverse spin and transverse momentum dependent distributions (TMDs) study are crucial for a more complete understanding of the nucleon structure and the dynamics of the strong interaction. The transverse spin structure and the TMDs are the subject of increasingly intense theoretical and experimental study recently. With a high luminosity electron beam facility, JLab has played a major role in the worldwide effort to study both the longitudinal and transverse spin structure. Highlights of recent results will be presented. With 12-GeV energy upgrade, JLab will provide the most precise measurements in the valence quark region to close a chapter in longitudinal spin study. JLab will also perform a multi-dimensional mapping of the transverse spin structure and TMDs in the valence quark region through Semi-Inclusive DIS (SIDIS) experiments, providing a 3-d partonic picture of the nucleon in momentum space and extracting the u and d quark tensor charges of the nucleon. The precision mapping of TMDs will also allow a detailed study of the quark orbital motion and its dynamics.

  8. EPA LABORATORIES IMPLEMENT EMS PROGRAM

    EPA Science Inventory

    This paper highlights the breadth and magnitude of carrying out an effective Environmental Management System (EMS) program at the U.S. EPA's research and development laboratories. Federal research laboratories have unique operating challenges compared to more centralized industr...

  9. Joint multiple imputation for longitudinal outcomes and clinical events that truncate longitudinal follow-up.

    PubMed

    Hu, Bo; Li, Liang; Greene, Tom

    2016-07-30

    Longitudinal cohort studies often collect both repeated measurements of longitudinal outcomes and times to clinical events whose occurrence precludes further longitudinal measurements. Although joint modeling of the clinical events and the longitudinal data can be used to provide valid statistical inference for target estimands in certain contexts, the application of joint models in medical literature is currently rather restricted because of the complexity of the joint models and the intensive computation involved. We propose a multiple imputation approach to jointly impute missing data of both the longitudinal and clinical event outcomes. With complete imputed datasets, analysts are then able to use simple and transparent statistical methods and standard statistical software to perform various analyses without dealing with the complications of missing data and joint modeling. We show that the proposed multiple imputation approach is flexible and easy to implement in practice. Numerical results are also provided to demonstrate its performance. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Family-Based Association Tests with longitudinal measurements: handling missing data.

    PubMed

    Ding, Xiao; Laird, Nan

    2009-01-01

    Several family-based approaches have been previously proposed to enhance the power for testing genetic association when the traits are measured longitudinally or repeatedly. In this paper, we show that some of these FBAT approaches can be easily extended to accommodate incomplete data and remain unbiased tests. We also show that because of the nature of FBAT approaches, we can impute the missing phenotypes without biasing our tests and achieve higher power. We propose two imputation techniques based on E-M algorithm and the conditional mean model, respectively. Through simulation studies, these two imputation techniques are shown to have correct false positive rate and generally achieve higher power than complete case analysis or simple mean-imputation. Application of these approaches for testing an association between Body Mass Index and a previously reported candidate SNP confirms our results.

  11. Family-Based Association Tests with Longitudinal Measurements: Handling Missing Data

    PubMed Central

    Ding, Xiao; Laird, Nan

    2009-01-01

    Several family-based approaches have been previously proposed to enhance the power for testing genetic association when the traits are measured longitudinally or repeatedly. In this paper, we show that some of these FBAT approaches can be easily extended to accommodate incomplete data and remain unbiased tests. We also show that because of the nature of FBAT approaches, we can impute the missing phenotypes without biasing our tests and achieve higher power. We propose two imputation techniques based on E-M algorithm and the conditional mean model, respectively. Through simulation studies, these two imputation techniques are shown to have correct false positive rate and generally achieve higher power than complete case analysis or simple mean-imputation. Application of these approaches for testing an association between Body Mass Index and a previously reported candidate SNP confirms our results. PMID:19365136

  12. Longitudinal elliptically polarized electromagnetic waves in off-diagonal magnetoelectric split-ring composites.

    PubMed

    Chui, S T; Wang, Weihua; Zhou, L; Lin, Z F

    2009-07-22

    We study the propagation of plane electromagnetic waves through different systems consisting of arrays of split rings of different orientations. Many extraordinary EM phenomena were discovered in such systems, contributed by the off-diagonal magnetoelectric susceptibilities. We find a mode such that the electric field becomes elliptically polarized with a component in the longitudinal direction (i.e. parallel to the wavevector). Even though the group velocity [Formula: see text] and the wavevector k are parallel, in the presence of damping, the Poynting vector does not just get 'broadened', but can possess a component perpendicular to the wavevector. The speed of light can be real even when the product ϵμ is negative. Other novel properties are explored.

  13. "Curso de Vulcanología General": Web-education efforts on volcanic hazards for the Latin American region from Mexico.

    NASA Astrophysics Data System (ADS)

    Delgado, Hugo

    2016-04-01

    Education of volcanic hazards is a never-ending task in countries where volcanoes erupt very frequently as they do in the Latin American region (LAR). Eleven countries in the LAR have active volcanoes within their territories and some volcanoes are located in between countries so the volcanic hazards associated to the eruption of those volcanoes affect more than one country. Besides, countries without volcanoes within their territory (i. e. Belize, Honduras or Brazil) can be impacted as well. Personnel working at several volcano observatories in the LAR need training in Volcanology and, more importantly, in Volcanic Hazards. Unfortunately, Volcanology is a discipline that is not taught at universities of some countries. Even worse, Earth Sciences are not even taught at high education centers in some countries of the LAR. Thus, there is an important need for the acquisition of volcanological knowledge by the personnel working at volcano observatories but there are no possibilities for them to study at their countries or they are impended for travel abroad for training. The international course: "Curso de Vulcanología General" taught from Mexico City at the Universidad Nacional Autónoma de México (UNAM) has been successfully implemented and has been active over the last five years. Nearly 700 students have participated in this course although only ~150 have been awarded the certificate UNAM grants to the students who have concluded the course successfully. This course has been sponsored by UNAM, ALVO (Latin American Volcanological Association) and IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior). More than 50 lecturers from LAR, Europe and US have been involved in these courses. Here, Reflections on the course, the opportunities sparkled, the educational tools, benefits, statistics and virtues of the course are presented.

  14. Novel and emerging strategies for longitudinal data collection.

    PubMed

    Udtha, Malini; Nomie, Krystle; Yu, Erica; Sanner, Jennifer

    2015-03-01

    To describe novel and emerging strategies practiced globally in research to improve longitudinal data collection. In research studies, numerous strategies such as telephone interviews, postal mailing, online questionnaires, and electronic mail are traditionally utilized in longitudinal data collection. However, due to technological advances, novel and emerging strategies have been applied to longitudinal data collection, such as two-way short message service, smartphone applications (or "apps"), retrieval capabilities applied to the electronic medical record, and an adapted cloud interface. In this review, traditional longitudinal data collection strategies are briefly described, emerging and novel strategies are detailed and explored, and information regarding the impact of novel methods on participant response rates, the timeliness of participant responses, and cost is provided. We further discuss how these novel and emerging strategies affect longitudinal data collection and advance research, specifically nursing research. Evidence suggests that the novel and emerging longitudinal data collection strategies discussed in this review are valuable approaches to consider. These strategies facilitate collecting longitudinal research data to better understand a variety of health-related conditions. Future studies, including nursing research, should consider using novel and emerging strategies to advance longitudinal data collection. A better understanding of novel and emerging longitudinal data collection strategies will ultimately improve longitudinal data collection as well as foster research efforts. Nurse researchers, along with all researchers, must be aware of and consider implementing novel and emerging strategies to ensure future healthcare research success. © 2014 Sigma Theta Tau International.

  15. Busca de estruturas em grandes escalas em altos redshifts

    NASA Astrophysics Data System (ADS)

    Boris, N. V.; Sodrã©, L., Jr.; Cypriano, E.

    2003-08-01

    A busca por estruturas em grandes escalas (aglomerados de galáxias, por exemplo) é um ativo tópico de pesquisas hoje em dia, pois a detecção de um único aglomerado em altos redshifts pode por vínculos fortes sobre os modelos cosmológicos. Neste projeto estamos fazendo uma busca de estruturas distantes em campos contendo pares de quasares próximos entre si em z Â3 0.9. Os pares de quasares foram extraídos do catálogo de Véron-Cetty & Véron (2001) e estão sendo observados com os telescópios: 2,2m da University of Hawaii (UH), 2,5m do Observatório de Las Campanas e com o GEMINI. Apresentamos aqui a análise preliminar de um par de quasares observado nos filtros i'(7800 Å) e z'(9500 Å) com o GEMINI. A cor (i'-z') mostrou-se útil para detectar objetos "early-type" em redshifts menores que 1.1. No estudo do par 131046+0006/J131055+0008, com redshift ~ 0.9, o uso deste método possibilitou a detecção de sete objetos candidatos a galáxias "early-type". Num mapa da distribuição projetada dos objetos para 22 < i' < 25 observou-se que estas galáxias estão localizadas próximas a um dos quasares e há indícios de que estejam aglomeradas dentro de um área de ~ 6 arcmin2. Se esse for o caso, estes objetos seriam membros de uma estrutura em grande escala. Um outro argumento em favor dessa hipótese é que eles obedecem uma relação do tipo Kormendy (raio equivalente X brilho superficial dentro desse raio), como a apresentada pelas galáxias elípticas em z = 0.

  16. [Methodological problems of longitudinal studies on schizophrenia].

    PubMed

    Häfner, H; an der Heiden, W

    2000-05-01

    Longitudinal studies are a key to understanding schizophrenia. They are the more informative, the longer the periods covered. Hence, good studies into the course of schizophrenia almost exclusively involve a lot of effort and cost. In practice, however, time-consuming methods and design variables must be avoided. The pitfalls this constraint produces are instructive of the difficulties longitudinal studies are faced with in striving for valid results. For reasons of research economy, requirements must be adjusted to study objectives. Studies into the short term course are less time-consuming, but because of the rapid changes in the illness course study intervals should be defined clearly and observed strictly. In long-term studies, too, one source of error lies in the highly varying lengths of illness of the patients studied. Even some of the classic long-term studies are marred by this error. The beginning of the follow-up period should be comparable across the study cohort and as close to illness onset as possible. To obtain generally valid results the probands must be representative of all the illness cases in the general population not only at the outset, but also all the later stages of the study. Besides the efforts to avoid attrition in the study cohort, ways must be found for correcting and estimating data for an acceptable proportion of drop-outs. In the analysis of course and outcome the indicators chosen must be apt to the traditional subtypes as well as to a theoretical symptom patterns and empirical symptom structures. In the context of typical design variables of longitudinal studies the assets and weaknesses of two retrospective and one prospective design will be discussed. Concerning the social course, importance of disease-independent factors, such as age, sex and level of social development at illness onset, as well as of control groups will be demonstrated. Predictor models will be discussed with reference to the direct and indirect influences

  17. Emotion regulation and childhood aggression: longitudinal associations.

    PubMed

    Röll, Judith; Koglin, Ute; Petermann, Franz

    2012-12-01

    Accumulating evidence suggests that emotion dysregulation is associated with psychopathology. This paper provides a review of recent longitudinal studies that investigate the relationship between emotion regulation and aggressive behavior in childhood age. While there is substantial evidence for assuming a close relation of emotion regulation and aggressive behavior, moderating and mediating factors like gender and peer rejection have been established. Furthermore, results suggest emotion dysregulation as an important risk factor of aggressive behavior. Several directions for future research are pointed out to further validate and refine the reviewed relationships.

  18. Fracture structure near a longitudinal shear macrorupture

    NASA Astrophysics Data System (ADS)

    Goldstein, R. V.; Osipenko, N. M.

    2012-09-01

    Fracture evolution the near a main longitudinal shear in the presence of normal stresses is studied. Experiments with model materials (gypsum, cheese) showed that a multiscale echelon structure of cracks feathering the main rupture is formed under the shear domination conditions. A system of small cracks in the initial echelon is replaced by an echelon of larger and sparser cracks. Intensive transverse compression along the normal to the shear plane, which imitates the initial stress concentrator, takes the fracture region away from the shear plane. A model of evolution development of the observed echelon structure along the main rupture front under the shear domination conditions is proposed.

  19. Linear stability of streamwise developing longitudinal vortices

    NASA Technical Reports Server (NTRS)

    Spall, Robert E.

    1993-01-01

    The linear stability of numerical solutions to the quasicylindrical equations of motion for swirling flows is investigated. Initial conditions are derived from Batchelor's similarity solution for a trailing line vortex. The stability calculations are performed using a 2nd-order accurate finitedifference scheme on a staggered grid with the accuracy of the computed eigenvalues enhanced through Richardson extrapolation. The streamwise development of both viscous and inviscid instability modes is discussed for low and high swirl cases. The effect of adverse and favorable pressure gradients on the viscous stability of a longitudinal vortex is also investigated.

  20. Longitudinal Diagnostics for Short Electron Beam Bunches

    SciTech Connect

    Loos, H.; /SLAC

    2010-06-11

    Single-pass free electron lasers require high peak currents from ultra-short electron bunches to reach saturation and an accurate measurement of bunch length and longitudinal bunch profile is necessary to control the bunch compression process from low to high beam energy. The various state-of-the-art diagnostics methods from ps to fs time scales using coherent radiation detection, RF deflection, and other techniques are presented. The use of linear accelerators as drivers for free electron lasers (FEL) and the advent of single-pass (SASE) FELs has driven the development of a wide range of diagnostic techniques for measuring the length and longitudinal distribution of short and ultra-short electron bunches. For SASE FELs the radiation power and the length of the undulator needed to achieve saturation depend strongly on the charge density of the electron beam. In the case of X-ray FELs, this requires the accelerator to produce ultra-high brightness beams with micron size transverse normalized emittances and peak currents of several kA through several stages of magnetic bunch compression. Different longitudinal diagnostics are employed to measure the peak current and bunch profile along these stages. The measurement techniques can be distinguished into different classes. Coherent methods detect the light emitted from the beam by some coherent radiation process (spectroscopic measurement), or directly measure the Coulomb field traveling with the beam (electro-optic). Phase space manipulation techniques map the time coordinate onto a transverse dimension and then use conventional transverse beam diagnostics (transverse deflector, rf zero-phasing). Further methods measure the profile or duration of an incoherent light pulse emitted by the bunch at wavelengths much shorted than the bunch length (streak camera, fluctuation technique) or modulate the electron beam at an optical wavelength and then generate a narrow bandwidth radiation pulse with the longitudinal profile of

  1. Cross-Sectional, Longitudinal and Composite Longitudinal Data on the Career Maturity Inventory Scale.

    ERIC Educational Resources Information Center

    Adelstein, Diane M.; Webster, Dennis W.

    1979-01-01

    Compared the results obtained by two traditional designs on the Career Maturity Inventory-Attitude Scale with the effects of an alternative design: constructing a composite longitudinal gradient. The two traditional methodologies yielded different results from each other for males, but not for females. (Author)

  2. A Class of Markov Models for Longitudinal Ordinal Data

    PubMed Central

    Lee, Keunbaik; Daniels, Michael J.

    2009-01-01

    Summary Generalized linear models with serial dependence are often used for short longitudinal series. Heagerty (2002, Biometrics 58, 342–351) has proposed marginalized transition models for the analysis of longitudinal binary data. In this article, we extend this work to accommodate longitudinal ordinal data. Fisher-scoring algorithms are developed for estimation. Methods are illustrated on quality-of-life data from a recent colorectal cancer clinical trial. PMID:18078479

  3. Longitudinal Studies of Attitude Change: Issues and Methods

    DTIC Science & Technology

    1975-04-01

    relative contributions of variables which are presently influencing attitudes from historical variables. Conversely a longitudinal method can be used to...different training techniques. Neidt and Meredith (1966) used a longitudinal method to determine the changes in attitudes of a single group of Air... longitudinal method is viewed as the most promising for measurement of change. With the increasing improvement in unobtrusive measures (e.g., Webb

  4. Splinting of Longitudinal Fracture: An Innovative Approach

    PubMed Central

    Bansal, Rashmi; Chowdhary, Priyanka; Gurtu, Anuraag; Mehrotra, Nakul; Kishore, Abhinav

    2016-01-01

    Trauma may result in craze lines on the enamel surface, one or more fractured cusps of posterior teeth, cracked tooth syndrome, splitting of posterior teeth, and vertical fracture of root. Out of these, management of some fractures is of great challenge and such teeth are generally recommended for extraction. Literature search reveals attempts to manage such fractures by full cast crown, orthodontic wires, and so forth, in which consideration was given to extracoronal splinting only. However, due to advancement in materials and technologies, intracoronal splinting can be achieved as well. In this case report, longitudinal fractures in tooth #27, tooth #37, and tooth #46 had occurred. In #27, fracture line was running mesiodistally involving the pulpal floor resulting in a split tooth. In teeth 37 and 46, fractures of the mesiobuccal cusp and mesiolingual cusp were observed, respectively. They were restored with cast gold inlay and full cast crown, respectively. Longitudinal fracture of 27 was treated with an innovative approach using intracanal reinforced composite with Ribbond, external reinforcement with an orthodontic band, and full cast metal crown to splint the split tooth. PMID:27247808

  5. Analyzing incomplete longitudinal clinical trial data.

    PubMed

    Molenberghs, Geert; Thijs, Herbert; Jansen, Ivy; Beunckens, Caroline; Kenward, Michael G; Mallinckrodt, Craig; Carroll, Raymond J

    2004-07-01

    Using standard missing data taxonomy, due to Rubin and co-workers, and simple algebraic derivations, it is argued that some simple but commonly used methods to handle incomplete longitudinal clinical trial data, such as complete case analyses and methods based on last observation carried forward, require restrictive assumptions and stand on a weaker theoretical foundation than likelihood-based methods developed under the missing at random (MAR) framework. Given the availability of flexible software for analyzing longitudinal sequences of unequal length, implementation of likelihood-based MAR analyses is not limited by computational considerations. While such analyses are valid under the comparatively weak assumption of MAR, the possibility of data missing not at random (MNAR) is difficult to rule out. It is argued, however, that MNAR analyses are, themselves, surrounded with problems and therefore, rather than ignoring MNAR analyses altogether or blindly shifting to them, their optimal place is within sensitivity analysis. The concepts developed here are illustrated using data from three clinical trials, where it is shown that the analysis method may have an impact on the conclusions of the study.

  6. Analysis strategies for longitudinal attachment loss data.

    PubMed

    Beck, J D; Elter, J R

    2000-02-01

    The purpose of this invited review is to describe and discuss methods currently in use to quantify the progression of attachment loss in epidemiological studies of periodontal disease, and to make recommendations for specific analytic methods based upon the particular design of the study and structure of the data. The review concentrates on the definition of incident attachment loss (ALOSS) and its component parts; measurement issues including thresholds and regression to the mean; methods of accounting for longitudinal change, including changes in means, changes in proportions of affected sites, incidence density, the effect of tooth loss and reversals, and repeated events; statistical models of longitudinal change, including the incorporation of the time element, use of linear, logistic or Poisson regression or survival analysis, and statistical tests; site vs person level of analysis, including statistical adjustment for correlated data; the strengths and limitations of ALOSS data. Examples from the Piedmont 65+ Dental Study are used to illustrate specific concepts. We conclude that incidence density is the preferred methodology to use for periodontal studies with more than one period of follow-up and that the use of studies not employing methods for dealing with complex samples, correlated data, and repeated measures does not take advantage of our current understanding of the site- and person-level variables important in periodontal disease and may generate biased results.

  7. Longitudinal Predictors of Institutionalization in Old Age

    PubMed Central

    Hajek, André; Brettschneider, Christian; Lange, Carolin; Posselt, Tina; Wiese, Birgitt; Steinmann, Susanne; Weyerer, Siegfried; Werle, Jochen; Pentzek, Michael; Fuchs, Angela; Stein, Janine; Luck, Tobias; Bickel, Horst; Mösch, Edelgard; Wagner, Michael; Jessen, Frank; Maier, Wolfgang; Scherer, Martin

    2015-01-01

    Objective To investigate time-dependent predictors of institutionalization in old age using a longitudinal approach. Methods In a representative survey of the German general population aged 75 years and older predictors of institutionalization were observed every 1.5 years over six waves. Conditional fixed-effects logistic regressions (with 201 individuals and 960 observations) were performed to estimate the effects of marital status, depression, dementia, and physical impairments (mobility, hearing and visual impairments) on the risk of admission to old-age home or nursing home. By exploiting the longitudinal data structure using panel econometric models, we were able to control for unobserved heterogeneity such as genetic predisposition and personality traits. Results The probability of institutionalization increased significantly with occurrence of widowhood, depression, dementia, as well as walking and hearing impairments. In particular, the occurrence of widowhood (OR = 78.3), dementia (OR = 154.1) and substantial mobility impairment (OR = 36.7) were strongly associated with institutionalization. Conclusion Findings underline the strong influence of loss of spouse as well as dementia on institutionalization. This is relevant as the number of old people (a) living alone and (b) suffering from dementia is expected to increase rapidly in the next decades. Consequently, it is supposed that the demand for institutionalization among the elderly will increase considerably. Practitioners as well as policy makers should be aware of these upcoming challenges. PMID:26658776

  8. Preceptor teaching tips in longitudinal clerkships.

    PubMed

    Latessa, Robyn; Schmitt, Anthony; Beaty, Norma; Buie, Stephen; Ray, Lisa

    2016-06-01

    In longitudinal integrated clerkships (LICs), the continuous preceptor and student relationship over time creates opportunities for more in-depth teaching approaches than shorter preceptorships allow. We identify student perceptions of the most effective teaching practices and develop tips for LIC preceptors. The first four third-year medical student classes completing the Asheville LIC of the University of North Carolina School of Medicine (UNC SOM) formed the subject group. Between June and August 2013, a trained research assistant (AS) conducted semi-structured interviews with all 27 UNC SOM Asheville LIC students. Interviews were transcribed and coded by thematic analysis. All 27 (100%) students participated in the interviews. We identified seven main themes of successful precepting practices: enhance teaching; create bring-backs (learning topics to bring back to preceptors); support patient ownership; structure clinic; improve feedback; engage learners; and develop a relationship. These themes were condensed into nine preceptor tips for teaching in LICs. The longitudinal relationship of preceptor and student in LIC models affords specific, important opportunities for teaching and learning. The concise list of LIC preceptor tips can be used by preceptors to further optimise their teaching in the LIC setting. We identify student perceptions of the most effective teaching practices and develop tips for LIC preceptors. © 2015 John Wiley & Sons Ltd.

  9. Anonymization of Longitudinal Electronic Medical Records

    PubMed Central

    Tamersoy, Acar; Loukides, Grigorios; Nergiz, Mehmet Ercan; Saygin, Yucel; Malin, Bradley

    2013-01-01

    Electronic medical record (EMR) systems have enabled healthcare providers to collect detailed patient information from the primary care domain. At the same time, longitudinal data from EMRs are increasingly combined with biorepositories to generate personalized clinical decision support protocols. Emerging policies encourage investigators to disseminate such data in a deidentified form for reuse and collaboration, but organizations are hesitant to do so because they fear such actions will jeopardize patient privacy. In particular, there are concerns that residual demographic and clinical features could be exploited for reidentification purposes. Various approaches have been developed to anonymize clinical data, but they neglect temporal information and are, thus, insufficient for emerging biomedical research paradigms. This paper proposes a novel approach to share patient-specific longitudinal data that offers robust privacy guarantees, while preserving data utility for many biomedical investigations. Our approach aggregates temporal and diagnostic information using heuristics inspired from sequence alignment and clustering methods. We demonstrate that the proposed approach can generate anonymized data that permit effective biomedical analysis using several patient cohorts derived from the EMR system of the Vanderbilt University Medical Center. PMID:22287248

  10. A longitudinal study of urea cycle disorders.

    PubMed

    Batshaw, Mark L; Tuchman, Mendel; Summar, Marshall; Seminara, Jennifer

    2014-01-01

    The Urea Cycle Disorders Consortium (UCDC) is a member of the NIH funded Rare Diseases Clinical Research Network and is performing a longitudinal study of 8 urea cycle disorders (UCDs) with initial enrollment beginning in 2006. The consortium consists of 14 sites in the U.S., Canada and Europe. This report summarizes data mining studies of 614 patients with UCDs enrolled in the UCDC's longitudinal study protocol. The most common disorder is ornithine transcarbamylase deficiency, accounting for more than half of the participants. We calculated the overall prevalence of urea cycle disorders to be 1/35,000, with 2/3rds presenting initial symptoms after the newborn period. We found the mortality rate to be 24% in neonatal onset cases and 11% in late onset cases. The most common precipitant of clinical hyperammonemic episodes in the post-neonatal period was intercurrent infections. Elevations in both blood ammonia and glutamine appeared to be biomarkers for neurocognitive outcome. In terms of chronic treatment, low protein diet appeared to result in normal weight but decreased linear growth while N-scavenger therapy with phenylbutyrate resulted in low levels of branched chain amino acids. Finally, we found an unexpectedly high risk for hepatic dysfunction in patients with ornithine transcarbamylase deficiency. This natural history study illustrates how a collaborative study of a rare genetic disorder can result in an improved understanding of morbidity and disease outcome.

  11. Optimization of longitudinal corrections of helical gears

    NASA Astrophysics Data System (ADS)

    He, Dawei; Fang, Zongde

    1992-07-01

    FEM and mathematical programming are used to obtain optimal longitudinal corrections of helical gears. Consideration is given to: the simultaneous engagement of three pairs of teeth; the influence of deformation of rims and webs; and the influence of deformation of shafts and bearings. A gear surface complex flexibility matrix is established in order to reduce the computer time needed. In the optimization of longitudinal corrections, a large number of iteration computations must be performed. Many meshing positions and contact lines must be considered. There are a great number of points on which forces may act. Flexibilities of points on which forces act are needed in iteration computations. In the past, flexibilities of contact points are computed when needed; as a result, the computer time required is unnecessarily great. Flexibilities of all points on which forces may act and store gear surface complex flexibility matrix in a database are computed. The flexibilities are recalled from data base whenever needed; as a result, the computer time needed is greatly reduced. Aircraft gears in actual use are taken as examples. Calculated results show that optimization or very good load equalization can be attained in theory.

  12. MULTILINEAR TENSOR REGRESSION FOR LONGITUDINAL RELATIONAL DATA.

    PubMed

    Hoff, Peter D

    2015-09-01

    A fundamental aspect of relational data, such as from a social network, is the possibility of dependence among the relations. In particular, the relations between members of one pair of nodes may have an effect on the relations between members of another pair. This article develops a type of regression model to estimate such effects in the context of longitudinal and multivariate relational data, or other data that can be represented in the form of a tensor. The model is based on a general multilinear tensor regression model, a special case of which is a tensor autoregression model in which the tensor of relations at one time point are parsimoniously regressed on relations from previous time points. This is done via a separable, or Kronecker-structured, regression parameter along with a separable covariance model. In the context of an analysis of longitudinal multivariate relational data, it is shown how the multilinear tensor regression model can represent patterns that often appear in relational and network data, such as reciprocity and transitivity.

  13. Colorado longitudinal twin study of reading disability.

    PubMed

    Wadsworth, Sally J; DeFries, John C; Olson, Richard K; Willcutt, Erik G

    2007-12-01

    The primary objectives of the present study are to introduce the Colorado Longitudinal Twin Study of Reading Disability, the first longitudinal twin study in which subjects have been specifically selected for having a history of reading difficulties, and to present some initial assessments of the stability of reading performance and cognitive abilities in this sample. Preliminary examination of the test scores of 124 twins with a history of reading difficulties and 154 twins with no history of reading difficulties indicates that over the 5- to 6-year interval between assessments, cognitive and reading performance are highly stable. As a group, those subjects with a history of reading difficulties had substantial deficits relative to control subjects on all measures at initial assessment, and significant deficits remained at follow-up. The stability noted for all cognitive and achievement measures was highest for a composite measure of reading, whose average stability correlation across groups was 0.80. Results of preliminary behavior genetic analyses for this measure indicated that shared genetic influences accounted for 86% and 49% of the phenotypic correlations between the two assessments for twin pairs with and without reading difficulties, respectively. In addition, genetic correlations reached unity for both groups, suggesting that the same genetic influences are manifested at both time points.

  14. Splinting of Longitudinal Fracture: An Innovative Approach.

    PubMed

    Bansal, Rashmi; Chowdhary, Priyanka; Gurtu, Anuraag; Mehrotra, Nakul; Kishore, Abhinav

    2016-01-01

    Trauma may result in craze lines on the enamel surface, one or more fractured cusps of posterior teeth, cracked tooth syndrome, splitting of posterior teeth, and vertical fracture of root. Out of these, management of some fractures is of great challenge and such teeth are generally recommended for extraction. Literature search reveals attempts to manage such fractures by full cast crown, orthodontic wires, and so forth, in which consideration was given to extracoronal splinting only. However, due to advancement in materials and technologies, intracoronal splinting can be achieved as well. In this case report, longitudinal fractures in tooth #27, tooth #37, and tooth #46 had occurred. In #27, fracture line was running mesiodistally involving the pulpal floor resulting in a split tooth. In teeth 37 and 46, fractures of the mesiobuccal cusp and mesiolingual cusp were observed, respectively. They were restored with cast gold inlay and full cast crown, respectively. Longitudinal fracture of 27 was treated with an innovative approach using intracanal reinforced composite with Ribbond, external reinforcement with an orthodontic band, and full cast metal crown to splint the split tooth.

  15. Parental mediation and cyberbullying - a longitudinal study.

    PubMed

    Chng, Grace S; Liau, Albert; Khoo, Angeline; Li, Dongdong

    2014-01-01

    Parents use active and restrictive mediation strategies to guide and regulate children's online participation and the online risks they encounter. However, changes in parental mediation do occur over time and the effectiveness of these strategies on cyberbullying demands for further empirical investigation. The current study addresses these issues with a sample of 1084 students (49% girls) in a longitudinal, three-wave design. Gender differences were tested via multi-group analyses. Longitudinal growth models showed that parental use of both active and restrictive mediation decreased over time. For both types of mediation, the mean rate of change had a significant effect on boys' engagement in cyberbullying, but not for girls. Initial levels of restrictive mediation, but not active mediation, were found to be significantly predictive of cyberbullying in both genders. Girls had higher initial levels of both parental mediation types in comparison to boys. The results reveal that the effectiveness of active and restrictive mediation in relation to students' cyberbullying differs and informs us on gender differences. The implications of these results for parental education in online mediation are discussed.

  16. Initial Cognitive Performance Predicts Longitudinal Aviator Performance

    PubMed Central

    Jo, Booil; Adamson, Maheen M.; Kennedy, Quinn; Noda, Art; Hernandez, Beatriz; Zeitzer, Jamie M.; Friedman, Leah F.; Fairchild, Kaci; Scanlon, Blake K.; Murphy, Greer M.; Taylor, Joy L.

    2011-01-01

    Objectives. The goal of the study was to improve prediction of longitudinal flight simulator performance by studying cognitive factors that may moderate the influence of chronological age. Method. We examined age-related change in aviation performance in aircraft pilots in relation to baseline cognitive ability measures and aviation expertise. Participants were aircraft pilots (N = 276) aged 40–77.9. Flight simulator performance and cognition were tested yearly; there were an average of 4.3 (± 2.7; range 1–13) data points per participant. Each participant was classified into one of the three levels of aviation expertise based on Federal Aviation Administration pilot proficiency ratings: least, moderate, or high expertise. Results. Addition of measures of cognitive processing speed and executive function to a model of age-related change in aviation performance significantly improved the model. Processing speed and executive function performance interacted such that the slowest rate of decline in flight simulator performance was found in aviators with the highest scores on tests of these abilities. Expertise was beneficial to pilots across the age range studied; however, expertise did not show evidence of reducing the effect of age. Discussion. These data suggest that longitudinal performance on an important real-world activity can be predicted by initial assessment of relevant cognitive abilities. PMID:21586627

  17. Longitudinal Predictors of Institutionalization in Old Age.

    PubMed

    Hajek, André; Brettschneider, Christian; Lange, Carolin; Posselt, Tina; Wiese, Birgitt; Steinmann, Susanne; Weyerer, Siegfried; Werle, Jochen; Pentzek, Michael; Fuchs, Angela; Stein, Janine; Luck, Tobias; Bickel, Horst; Mösch, Edelgard; Wagner, Michael; Jessen, Frank; Maier, Wolfgang; Scherer, Martin; Riedel-Heller, Steffi G; König, Hans-Helmut

    2015-01-01

    To investigate time-dependent predictors of institutionalization in old age using a longitudinal approach. In a representative survey of the German general population aged 75 years and older predictors of institutionalization were observed every 1.5 years over six waves. Conditional fixed-effects logistic regressions (with 201 individuals and 960 observations) were performed to estimate the effects of marital status, depression, dementia, and physical impairments (mobility, hearing and visual impairments) on the risk of admission to old-age home or nursing home. By exploiting the longitudinal data structure using panel econometric models, we were able to control for unobserved heterogeneity such as genetic predisposition and personality traits. The probability of institutionalization increased significantly with occurrence of widowhood, depression, dementia, as well as walking and hearing impairments. In particular, the occurrence of widowhood (OR = 78.3), dementia (OR = 154.1) and substantial mobility impairment (OR = 36.7) were strongly associated with institutionalization. Findings underline the strong influence of loss of spouse as well as dementia on institutionalization. This is relevant as the number of old people (a) living alone and (b) suffering from dementia is expected to increase rapidly in the next decades. Consequently, it is supposed that the demand for institutionalization among the elderly will increase considerably. Practitioners as well as policy makers should be aware of these upcoming challenges.

  18. A longitudinal study of urea cycle disorders

    PubMed Central

    Batshaw, Mark L.; Tuchman, Mendel; Summar, Marshall; Seminara, Jennifer

    2014-01-01

    The urea cycle disorders consortium (UCDC) is a member of the NIH funded Rare Diseases Clinical Research Network and is performing a longitudinal study of 8 urea cycle disorders (UCD) with initial enrollment beginning in 2006. The consortium consists of 14 sites in the U.S., Canada and Europe. This report summarizes data mining studies of 614 patients with UCD enrolled in the UCDC’s longitudinal study protocol. The most common disorder is ornithine transcarbamylase deficiency, accounting for more than half of the participants. We calculated the overall prevalence of urea cycle disorders to be 1/35,000, with 2/3rds presenting initial symptoms after the newborn period. We found the mortality rate to be 24% in neonatal onset cases and 11% in late onset cases. The most common precipitant of clinical hyperammonemic episodes in the post-neonatal period was intercurrent infections. Elevations in both blood ammonia and glutamine appeared to be biomarkers for neurocognitive outcome. In terms of chronic treatment, low protein diet appeared to result in normal weight but decreased linear growth while N-scavenger therapy with phenybutyrate resulted in low levels of branched chain amino acids. Finally, we found an unexpectedly high risk for hepatic dysfunction in patients with ornithine transcarbamylase deficiency. This natural history study illustrates how a collaborative study of a rare genetic disorder can result in an improved understanding of morbidity and disease outcome. PMID:25135652

  19. Longitudinal Section AA; Lower Chord Plan Powerscourt Bridge, Spanning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Longitudinal Section A-A; Lower Chord Plan - Powerscourt Bridge, Spanning Chateauguay River, First Concession Road, Elgin/Hichinbrooke, Huntingdon County, Quebec, Canada, Chateaugay, Franklin County, NY

  20. Coupling and degenerating modes in longitudinal-torsional step horns.

    PubMed

    Harkness, Patrick; Lucas, Margaret; Cardoni, Andrea

    2012-12-01

    Longitudinal-torsional vibration is used and proposed for a variety of ultrasonic applications including motors, welding, and rock-cutting. To obtain this behavior in an ultrasonic step horn one can either, (i) couple the longitudinal and torsional modes of the horn by incorporating a ring of diagonal slits in the thick base section or, (ii) place helical flutes in the thin stem section to degenerate the longitudinal mode into a modified behavior with a longitudinal-torsional motion. This paper compares the efficacy of these two design approaches using both numerical and experimental techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Molecular mechanisms in the formation of the medial longitudinal fascicle

    PubMed Central

    Ahsan, Mansoor; Riley, Kerry-lyn; Schubert, Frank R

    2007-01-01

    The first neurons in the vertebrate brain form a stereotypical array of longitudinal and transversal axon tracts, the early axon scaffold. This scaffold is thought to lay down the basic structure for the later, more complex neuronal pathways in the brain. The ventral longitudinal tract is pioneered by neurons located at the ventral midbrain–forebrain boundary, which form the medial longitudinal fascicle. Recent studies have shed some light on the molecular mechanisms that control the development of the medial longitudinal fascicle. Here, we show that patterning molecules, notably the ventralizing signalling molecule Shh, are involved in the formation of medial longitudinal fascicle neurons and in medial longitudinal fascicle axon guidance. Downstream of Shh, several homeobox genes are expressed in the tegmentum. We describe the expression patterns of Sax1, Emx2, Six3, Nkx2.2 and Pax6 in the mesencephalon and pretectum in detail. Furthermore, we review the evidence of their molecular interactions, and their involvement in neuronal fate specification. In particular, Sax1 plays a major role in fate determination of medial longitudinal fascicle neurons. Finally, we discuss the available data on axon guidance mechanisms for the medial longitudinal fascicle, which suggest that different guidance molecules such as class 3 Semaphorins, Slits and Netrins act to determine the caudal and ventral course of the medial longitudinal fascicle axons. PMID:17623036

  2. Longitudinal Muscle Dysfunction in Achalasia Esophagus and Its Relevance

    PubMed Central

    Hong, Su Jin; Bhargava, Valmik

    2013-01-01

    Muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. Goal of this review is to summarize the role of longitudinal muscle in physiology and pathophysiology of esophageal sensory and motor function. Simultaneous manometry and ultrasound imaging that measure circular and longitudinal muscle contraction respectively reveal that during peristalsis 2 layers of the esophagus contract in perfect synchrony. On the other hand, during transient relaxation of the lower esophageal sphincter (LES), longitudinal muscle contracts independently of circular muscle. Recent studies provide novel insights, i.e., longitudinal muscle contraction of the esophagus induces LES relaxation and possibly descending relaxation of the esophagus. In achalasia esophagus and other motility disorders there is discoordination between the 2 muscle layers. Longitudinal muscle contraction patterns are different in the recently described three types of achalasia identified by high-resolution manometry. Robust contraction of the longitudinal muscle in type II achalasia causes pan-esophageal pressurization and is the mechanism of whatever little esophageal emptying that take place in the absence of peristalsis and impaired LES relaxation. It may be that preserved longitudinal muscle contraction is also the reason for superior outcome to medical/surgical therapy in type II achalasia esophagus. Prolonged contractions of longitudinal muscles of the esophagus is a possible mechanism of heartburn and "angina like" pain seen in esophageal motility disorders and possibly achalasia esophagus. Novel techniques to record longitudinal muscle contraction are on the horizon. Neuro-pharmacologic control of circular and longitudinal muscles is different, which provides an important opportunity for the development of novel pharmacological therapies to treat sensory and motor disorders of the esophagus. PMID:23667744

  3. Longitudinal Stability of Common TMJ Structural Disorders.

    PubMed

    Schiffman, E L; Ahmad, M; Hollender, L; Kartha, K; Ohrbach, R; Truelove, E L; Zhang, L; Hodges, J S; Sommers, E; Anderson, G C; Gonzalez, Y M; Guo, X; Look, J O

    2017-03-01

    The longitudinal course of temporomandibular joint (TMJ) disc displacement (DD) and degenerative joint disease (DJD) has never been conclusively described with magnetic resonance imaging and computed tomography, respectively. This 8-y observational study's objective was to assess the longitudinal stability of DD and DJD among 401 subjects. The Validation Project provided baseline measures; follow-up was performed in the TMJ Impact Project. With magnetic resonance imaging, 2 radiologists rendered a consensus diagnosis of normal/indeterminate, DD with reduction, or DD without reduction. Computed tomography consensus diagnoses included normal/indeterminate, grade 1 DJD, or grade 2 DJD. Radiologist reliability was assessed by kappa; a Hui-Walter model was used to estimate, after accounting for diagnostic disagreement, the frequency of diagnostic progression and reversal. Permutation tests were used to test the statistical influence of concurrent baseline diagnoses on diagnostic changes at follow-up. Of 789 baseline joint-specific soft tissue diagnoses of DD, 598 (76%) joints showed no change; 109 (14%) demonstrated progression; and 82 (10%) had reversal. Of 794 joints with baseline joint-specific hard tissue diagnoses of DJD, progression was observed in 122 (15%) joints, no change in 564 (71%), and reversal in 108 (14%). Radiologist reliability (kappa) was 0.73 (95% CI, 0.64 to 0.83) for DD and 0.76 (95% CI, 0.68 to 0.83) for DJD. After accounting for the influence of diagnostic disagreement, progression of hard tissue diagnoses in the right TMJ occurred in 15.2% of subjects (95% CI, 10.5% to 20.8%) and reversal in 8.3% (95% CI, 4.9% to 12.3%); results were similar for soft tissue diagnoses and the left TMJ. Concurrent baseline soft tissue diagnoses were associated with hard tissue diagnostic changes at follow-up ( P < 0.0001). Baseline hard tissue diagnoses showed no statistical association with soft tissue changes at follow-up ( P = 0.11). Longitudinally, 76% of

  4. The European Mobile System (EMS)

    NASA Technical Reports Server (NTRS)

    Jongejans, A.; Rogard, R.; Mistretta, I.; Ananasso, F.

    1993-01-01

    The European Space Agency is presently procuring an L band payload in order to promote a regional European L band system coping with the specific needs of the European market. The payload, and the two communications systems to be supported, are described below. The potential market for EMS in Europe is discussed.

  5. Analysis of aircraft longitudinal handling qualities

    NASA Technical Reports Server (NTRS)

    Hess, R. A.

    1981-01-01

    The optimal control model (OCM) of the human pilot is applied to the study of aircraft handling qualities. Attention is focused primarily on longitudinal tasks. The modeling technique differs from previous applications of the OCM in that considerable effort is expended in simplifying the pilot/vehicle analysis. After briefly reviewing the OCM, a technique for modeling the pilot controlling higher order systems is introduced. Following this, a simple criterion for determining the susceptibility of an aircraft to pilot induced oscillations (PIO) is formulated. Finally, a model-based metric for pilot rating prediction is discussed. The resulting modeling procedure provides a relatively simple, yet unified approach to the study of a variety of handling qualities problems.

  6. A Longitudinal View of HTTP Traffic

    NASA Astrophysics Data System (ADS)

    Callahan, Tom; Allman, Mark; Paxson, Vern

    In this paper we analyze three and a half years of HTTP traffic observed at a small research institute to characterize the evolution of various facets of web operation. While our dataset is modest in terms of user population, it is unique in its temporal breadth. We leverage the longitudinal data to study various characteristics of the traffic, from client and server behavior to object and connection characteristics. In addition, we assess how the delivery of content is structured across our datasets, including the use of browser caches, the efficacy of network-based proxy caches, and the use of content delivery networks. While each of the aspects we study has been investigated to some extent in prior work, our contribution is a unique long-term characterization.

  7. Parameter identification and modeling of longitudinal aerodynamics

    NASA Technical Reports Server (NTRS)

    Aksteter, J. W.; Parks, E. K.; Bach, R. E., Jr.

    1995-01-01

    Using a comprehensive flight test database and a parameter identification software program produced at NASA Ames Research Center, a math model of the longitudinal aerodynamics of the Harrier aircraft was formulated. The identification program employed the equation error method using multiple linear regression to estimate the nonlinear parameters. The formulated math model structure adhered closely to aerodynamic and stability/control theory, particularly with regard to compressibility and dynamic manoeuvring. Validation was accomplished by using a three degree-of-freedom nonlinear flight simulator with pilot inputs from flight test data. The simulation models agreed quite well with the measured states. It is important to note that the flight test data used for the validation of the model was not used in the model identification.

  8. Multivariate Longitudinal Modeling of Cognitive Aging

    PubMed Central

    Robitaille, Annie; Muniz, Graciela; Piccinin, Andrea M.; Johansson, Boo; Hofer, Scott M.

    2013-01-01

    We illustrate the use of the parallel latent growth curve model using data from OCTO-Twin. We found a significant intercept-intercept and slope-slope association between processing speed and visuospatial ability. Within-person correlations among the occasion-specific residuals were significant, suggesting that the occasion-specific fluctuations around individual’s trajectories, after controlling for intraindividual change, are related between both outcomes. Random and fixed effects for visuospatial ability are reduced when we include structural parameters (directional growth curve model) providing information about changes in visuospatial abilities after controlling for processing speed. We recommend this model to researchers interested in the analysis of multivariate longitudinal change, as it permits decomposition and directly interpretable estimates of association among initial levels, rates of change, and occasion-specific variation. PMID:23589712

  9. Simulation of longitudinal coupled-bunch instabilities

    SciTech Connect

    Thompson, K.A.

    1991-02-07

    The purpose of this note is to document some work done as part of the effort directed at designing and simulating a bunch-by-bunch feedback system to control longitudinal coupled bunch instabilities in the B-factory. In particular, I discuss the ring model used in the simulation program developed to study this feedback system. Basically the simulation is a simple tracking program in which the rf drive voltage, the wakefields due to all the bunches, the synchrotron radiation losses, and the kicks applied to the bunches by the bunch-by-bunch feedback are all modelled as voltages applied at a single, discrete point in the ring. The computation of the bunch-by-bunch feedback voltages may of course be done by any desired algorithms. An example and discussion of the general behavior without bunch-by-bunch feedback is given at the end of this report.

  10. Longitudinal ultrasonic waves in DC electric field

    NASA Astrophysics Data System (ADS)

    Sobotka, Jerzy

    2009-06-01

    The results of experimental studies of the propagation of longitudinal waves in saturated rock samples in which there is a flow of electric charges are presented. It is shown that the electric field affects elastic parameters in heterophase media by changing their dynamic characteristics. The aim of the study of the effect of electric field on the propagation of elastic waves in saturated porous media was to determine the optimum conditions for this effect, and to construct a set of effective parameters which could be used to increase the effectiveness of seismoacoustic prospecting methods, particularly acoustic logging, and be helpful for developing new methods of increasing the effectiveness of oil extraction from productive wells.

  11. The longitudinal development of clusters in French.

    PubMed

    Demuth, Katherine; McCullough, Elizabeth

    2009-03-01

    Studies of English and German find that children tend to acquire word-final consonant clusters before word-initial consonant clusters. This order of acquisition is generally attributed to articulatory, frequency and/or morphological factors. This contrasts with recent experimental findings from French, where two-year-olds were better at producing word-initial than word-final clusters (Demuth & Kehoe, 2006). The purpose of the present study was to examine French-speaking children's longitudinal acquisition of clusters to determine if these results replicate developmentally. Analysis of spontaneous speech productions from two French-speaking children between one and three years confirmed the earlier acquisition of initial clusters, even when sonority factors were controlled. The findings suggest that French-speaking children acquire complexity at the beginnings of words before complexity appears word-finally. The role of frequency, morphological, structural and input factors is discussed.

  12. Beam Tomography in Longitudinal Phase Space

    NASA Astrophysics Data System (ADS)

    Mane, V.; Wei, J.; Peggs, S.

    1997-05-01

    Longitudinal particle motion in circular accelerators is typically monitored by one dimensional (1-D) profiles. Adiabatic particle motion in 2-D phase space can be reconstructed with tomographic techniques, using 1-D profiles. In this paper, we discuss a filtered backprojection algorithm, with a high pass ramp or Hann filter, for phase space reconstruction. The algorithm uses several projections of the beam at equally spaced angles over half a synchrotron period. A computer program RADON has been developed to process digitized mountain range data and do the phase space reconstruction for the AGS, and later for Relativistic Heavy Ion Collider (RHIC). Analysis has been performed to determine the sensitivity to machine parameters and data acquisition errors. During the Sextant test of RHIC in early 1997, this program has been successfully employed to reconstruct the motion of Au^77+ beam in the AGS.

  13. Longitudinal predictors of high school completion.

    PubMed

    Barry, Melissa; Reschly, Amy L

    2012-06-01

    This longitudinal study examined predictors of dropout assessed in elementary school. Student demographic data, achievement, attendance, and ratings of behavior from the Behavior Assessment System for Children were used to predict dropout and completion. Two models, which varied on student sex and race, predicted dropout at rates ranging from 75% to 88%. Model A, which included the Behavioral Symptoms Index, School Problems composite, Iowa Tests of Basic Skills battery, and teacher ratings of student work habits, best predicted female and African American dropouts. Model B, which comprised the Adaptive Skills composite, the Externalizing composite, the School Problems composite, referral for a student support team meeting, and sex, was more accurate for predicting Caucasian dropouts. Both models demonstrated the same hit rates for predicting male dropouts. Recommendations for early warning indicators and linking predictors with interventions are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

  14. Longitudinal research on temperament in twins.

    PubMed

    Torgersen, A M

    1987-01-01

    The changing influence of genetic factors of temperamental individuality has been studied longitudinally in a group of 44 same-sexed twin pairs at four different ages from infancy to puberty. Previous results showed that genetic factors seemed to play an important role in the development of temperamental characteristics when the twins were in infancy and at six years of age. The present report shows that when the within-pair differences in temperament are studied again at age 15 years, the similarity of identical pairs is even higher than at earlier ages. When shared and nonshared stress in the twin pairs was assessed at this age, some interactions were found between within-pair differences in temperament, stress and zygosity.

  15. A Longitudinal Study of Adolescent Adjustment Following Family Transitions

    ERIC Educational Resources Information Center

    Ruschena, Eda; Prior, Margot; Sanson, Ann; Smart, Diana

    2005-01-01

    Background: This study examined the impact of family transitions, that is, parental separation, divorce, remarriage and death, upon the lives of Australian children and adolescents in a longitudinal study of temperament and development. Methods: Using longitudinal and concurrent questionnaire data, outcomes for young people experiencing…

  16. Longitudinal and transverse mode evolution in free electron laser

    SciTech Connect

    Dattoli, G.; Giannessi, L.; Georgii, R.

    1995-12-31

    We use the method of Padg approximants and Fourier transform techniques to treat analytically the problem of transverse and longitudinal mode evolution in FELs. We obtain simple relations providing a transparent understanding of the dynamic of pulse propagation effects and of transverse mode guiding. We discuss the interplay with inhomogeneous broadening effects and derive gain formulae including longitudinal and transverse mode couplings.

  17. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static longitudinal stability. 23.173 Section 23.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with...

  18. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static longitudinal stability. 23.173 Section 23.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with...

  19. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static longitudinal stability. 23.173 Section 23.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with...

  20. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 23.173 Section 23.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with...

  1. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static longitudinal stability. 23.173 Section 23.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with...

  2. Early Predictors of Adolescent Depression: A 7-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Mazza, James J.; Abbott, Robert D.; Fleming, Charles B.; Harachi, Tracy W.; Cortes, Rebecca C.; Park, Jisuk; Haggerty, Kevin P.; Catalano, Richard F.

    2009-01-01

    This study examined the longitudinal relationship of early elementary predictors to adolescent depression 7 years later. The sample consisted of 938 students who have been part of a larger longitudinal study that started in 1993. Data collected from parents, teachers, and youth self-reports on early risk factors when students were in 1st and 2nd…

  3. Inspection of Pipelines Using the First Longitudinal Guided Wave Mode

    NASA Astrophysics Data System (ADS)

    Lowe, P. S.; Sanderson, R.; Pedram, S. K.; Boulgouris, N. V.; Mudge, P.

    Inspection of cylindrical structures using the first longitudinal Ultrasonic Guided Wave (UGW) mode has so far been predominantly neglected. This is due to its attenuative and dispersive behaviour, at common UGW operating frequencies (20-100 kHz). However, with the current knowledge on the level of attenuation in the first longitudinal wave mode and dispersion compensation techniques, the first longitudinal guided wave mode no longer need to be neglected. Furthermore, the first longitudinal guided wave mode has higher number of non-axisymmetric modes compared to other axisymmetric modes in the operating frequency. This will enhance the flaw sizing capability which makes the first longitudinal guided wave mode a viable prospect for UGW inspection of cylindrical structures. This study has been performed to investigate the potential of exciting the first longitudinal guided wave mode in isolation. Numerical investigations have been conducted to investigate the pure excitation of the first longitudinal guided wave mode. It has been shown that the first longitudinal guided wave mode can be used in UGW inspection effectively in isolation by adopting transducers with out of plane vibration for excitation. This can reduces the cost and weight of UGW inspection tooling. Numerical results are empirically validated.

  4. The estimate and measurement of longitudinal wave intensity

    NASA Astrophysics Data System (ADS)

    Ruisen, Ming

    1996-08-01

    Quasi-longitudinal waves are one type of structural waves, which are important at high frequencies. This paper studies the estimate theory and measurement technique of quasi-longitudinal waves, analyzes the bias error due to the effect of bending waves. In a two-dimensional quasi-longitudinal wave field, the intensity vector is the sum of the effective intensity vector and the intensity variation vector. Its axial component is proportional to two imaginary parts of cross spectral densities and in the measurement, it is measured by a pair of two-transducer arrays. In a onedimensional quasi-longitudinal wave field, the intensity variation is zero, the intensity is proportional to only one imaginary part of a cross spectral density and it can be measured using a two-transducer array. If bending and quasi-longitudinal waves coexist and the contribution from bending waves cannot be eliminated or reduced to a certain extent, the measured quasi-longitudinal wave intensity will contain a large error. The results measured on the three-beam structure show that quasi-longitudinal wave intensity can be accurately measured using the intensity technique when bending waves are negligible in comparison with quasi-longitudinal waves.

  5. Longitudinal Research with Sexual Assault Survivors: A Methodological Review

    ERIC Educational Resources Information Center

    Campbell, Rebecca; Sprague, Heather Brown; Cottrill, Sara; Sullivan, Cris M.

    2011-01-01

    Longitudinal research designs are relatively rare in the academic literature on rape and sexual assault despite their tremendous methodological rigor and scientific utility. In the interest of promoting wider use of such methods, we conducted a methodological review of projects that have used prospective longitudinal designs to study the…

  6. Longitudinal Research with Sexual Assault Survivors: A Methodological Review

    ERIC Educational Resources Information Center

    Campbell, Rebecca; Sprague, Heather Brown; Cottrill, Sara; Sullivan, Cris M.

    2011-01-01

    Longitudinal research designs are relatively rare in the academic literature on rape and sexual assault despite their tremendous methodological rigor and scientific utility. In the interest of promoting wider use of such methods, we conducted a methodological review of projects that have used prospective longitudinal designs to study the…

  7. Learning from Longitudinal Research in Criminology and the Health Sciences

    ERIC Educational Resources Information Center

    Vanderstaay, Steven L.

    2006-01-01

    This article reviews longitudinal research within criminology and the health sciences on the relationship between reading and criminal, delinquent, or antisocial behavior. Longitudinal research in criminology, medicine, and psychology examines the role of reading within a broad set of interactive processes, connecting literacy to public health via…

  8. Objectives, Design, and History of the National Longitudinal Study.

    ERIC Educational Resources Information Center

    Davis, J. A.; Collins, Elmer

    The National Longitudinal Study of the High School Class of 1972 (NLS) is a federally supported longitudinal study of a national sample of some 23,000 young people first surveyed as high school seniors in the spring of 1972. The historical precedents of such a study include the work of Friend and Haggert in a Boston settlement house, Louis…

  9. Learning from Longitudinal Research in Criminology and the Health Sciences

    ERIC Educational Resources Information Center

    Vanderstaay, Steven L.

    2006-01-01

    This article reviews longitudinal research within criminology and the health sciences on the relationship between reading and criminal, delinquent, or antisocial behavior. Longitudinal research in criminology, medicine, and psychology examines the role of reading within a broad set of interactive processes, connecting literacy to public health via…

  10. Adolescent Psychosocial Development: A Review of Longitudinal Models and Research

    ERIC Educational Resources Information Center

    Meeus, Wim

    2016-01-01

    This review used 4 types of longitudinal models (descriptive models, prediction models, developmental sequence models and longitudinal mediation models) to identify regular patterns of psychosocial development in adolescence. Eight patterns of adolescent development were observed across countries: (1) adolescent maturation in multiple…

  11. Longitudinal Trajectories of Perceived Body Weight: Adolescence to Early Adulthood

    ERIC Educational Resources Information Center

    Seo, Dong-Chul; Li, Kaigang

    2012-01-01

    Objective: To examine longitudinal trajectories of perceived weight from adolescence to early adulthood by gender. Methods: We analyzed 9 waves (1997-2005) of data from the National Longitudinal Survey of Youth (N = 8302) using Mplus. Results: Perceived overweight increased over time among girls and did not level off until 23 years of age. Blacks…

  12. Objectives, Design, and History of the National Longitudinal Study.

    ERIC Educational Resources Information Center

    Davis, J. A.; Collins, Elmer

    The National Longitudinal Study of the High School Class of 1972 (NLS) is a federally supported longitudinal study of a national sample of some 23,000 young people first surveyed as high school seniors in the spring of 1972. The historical precedents of such a study include the work of Friend and Haggert in a Boston settlement house, Louis…

  13. Adolescent Psychosocial Development: A Review of Longitudinal Models and Research

    ERIC Educational Resources Information Center

    Meeus, Wim

    2016-01-01

    This review used 4 types of longitudinal models (descriptive models, prediction models, developmental sequence models and longitudinal mediation models) to identify regular patterns of psychosocial development in adolescence. Eight patterns of adolescent development were observed across countries: (1) adolescent maturation in multiple…

  14. A Longitudinal Investigation of Individual Implementation of Educational Innovations.

    ERIC Educational Resources Information Center

    Hall, Gene E.

    Implementation is a key factor in shaping school policies. The Procedures for Adopting Educational Innovations Project conducted longitudinal studies of innovation implementation based on the Concerns-Based Adoption Model (CBAM). A key dimension of CBAM, Levels of Use of the Innovation (LoU), was assessed in three longitudinal studies over a…

  15. Future Orientation, Impulsivity, and Problem Behaviors: A Longitudinal Moderation Model

    ERIC Educational Resources Information Center

    Chen, Pan; Vazsonyi, Alexander T.

    2011-01-01

    In the current study, based on a sample of 1,873 adolescents between 11.4 and 20.9 years of age from the first 3 waves of the National Longitudinal Study of Adolescent Health, we investigated the longitudinal effects of future orientation on levels of and developmental changes in problem behaviors, while controlling for the effects by impulsivity;…

  16. Longitudinal Trajectories of Perceived Body Weight: Adolescence to Early Adulthood

    ERIC Educational Resources Information Center

    Seo, Dong-Chul; Li, Kaigang

    2012-01-01

    Objective: To examine longitudinal trajectories of perceived weight from adolescence to early adulthood by gender. Methods: We analyzed 9 waves (1997-2005) of data from the National Longitudinal Survey of Youth (N = 8302) using Mplus. Results: Perceived overweight increased over time among girls and did not level off until 23 years of age. Blacks…

  17. Beyond Terman: Contemporary Longitudinal Studies of Giftedness and Talent.

    ERIC Educational Resources Information Center

    Subotnik, Rena F., Ed.; Arnold, Karen D., Ed.

    This volume presents 16 papers describing recent longitudinal studies of giftedness. Papers have the following titles and authors: (1) "Longitudinal Study of Giftedness and Talent" (Rena F. Subotnik and Karen D. Arnold); (2) "The Illinois Valedictorian Project: Early Adult Careers of Academically Talented Male High School Students" (Karen D.…

  18. A Cautionary Note on Modeling Growth Trends in Longitudinal Data

    ERIC Educational Resources Information Center

    Kuljanin, Goran; Braun, Michael T.; DeShon, Richard P.

    2011-01-01

    Random coefficient and latent growth curve modeling are currently the dominant approaches to the analysis of longitudinal data in psychology. The application of these models to longitudinal data assumes that the data-generating mechanism behind the psychological process under investigation contains only a deterministic trend. However, if a…

  19. Longitudinal Outcomes for Mathematics Achievement for Students with Learning Disabilities

    ERIC Educational Resources Information Center

    Judge, Sharon; Watson, Silvana M. R.

    2011-01-01

    Using longitudinal data from the first 6 waves of the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K), the authors examined mathematics achievement and growth trajectories by learning disability (LD) subgroups. The 2-level (time-student) growth curve model showed that lower levels of mathematics achievement were already evident at…

  20. Longitudinal Predictors of Very Early Chinese Literacy Acquisition

    ERIC Educational Resources Information Center

    Tong, Xiuli; McBride-Chang, Catherine; Wong, Anita M.-Y.; Shu, Hua; Reitsma, Pieter; Rispens, Judith

    2011-01-01

    This 2-year longitudinal study examined both concurrent and longitudinal relations of a variety of reading-related cognitive tasks and Chinese word reading and word dictation among 187 Hong Kong Chinese kindergarteners aged 4-6. Homophone awareness, visual skills and syllable awareness were all uniquely associated with Chinese word reading across…

  1. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be...

  2. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be...

  3. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be...

  4. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be...

  5. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be...

  6. A Cautionary Note on Modeling Growth Trends in Longitudinal Data

    ERIC Educational Resources Information Center

    Kuljanin, Goran; Braun, Michael T.; DeShon, Richard P.

    2011-01-01

    Random coefficient and latent growth curve modeling are currently the dominant approaches to the analysis of longitudinal data in psychology. The application of these models to longitudinal data assumes that the data-generating mechanism behind the psychological process under investigation contains only a deterministic trend. However, if a…

  7. A Longitudinal Investigation of Individual Implementation of Educational Innovations.

    ERIC Educational Resources Information Center

    Hall, Gene E.

    Implementation is a key factor in shaping school policies. The Procedures for Adopting Educational Innovations Project conducted longitudinal studies of innovation implementation based on the Concerns-Based Adoption Model (CBAM). A key dimension of CBAM, Levels of Use of the Innovation (LoU), was assessed in three longitudinal studies over a…

  8. The Impact of Mixing Modes on Reliability in Longitudinal Studies

    ERIC Educational Resources Information Center

    Cernat, Alexandru

    2015-01-01

    Mixed-mode designs are increasingly important in surveys, and large longitudinal studies are progressively moving to or considering such a design. In this context, our knowledge regarding the impact of mixing modes on data quality indicators in longitudinal studies is sparse. This study tries to ameliorate this situation by taking advantage of a…

  9. Van Kampen modes for bunch longitudinal motion

    SciTech Connect

    Burov, A.; /Fermilab

    2010-09-01

    Conditions for existence, uniqueness and stability of bunch steady states are considered. For the existence uniqueness problem, simple algebraic equations are derived, showing the result both for the action and Hamiltonian domain distributions. For the stability problem, van Kampen theory is used. Emerging of discrete van Kampen modes show either loss of Landau damping, or instability. This method can be applied for an arbitrary impedance, RF shape and beam distribution function Available areas on intensity-emittance plane are shown for resistive wall wake and single harmonic, bunch shortening and bunch lengthening RF configurations. Language of van Kampen modes is a powerful tool for studying beam stability. Its unique efficiency reveals itself in those complicated cases, when the dielectric function cannot be obtained, as it is for the longitudinal bunch motion. Emergence of a discrete mode means either loss of Landau damping or instability. By definition, the discrete modes lie outside the continuous incoherent spectrum, but they still may stay within the bucket. In the last case, the discrete mode would disappear after a tiny portion of resonant particles would be added. However, if the discrete mode lie outside the bucket, the Landau damping cannot be restored by tiny perturbation of the particle distribution; LLD is called radical in that case. For a given bunch emittance and RF voltage, the intensity is limited either by reduction of the bucket acceptance or by (radical) LLD. In this paper, results are presented for longitudinal bunch stability in weak head-tail approximation and resistive wall impedance; three RF configurations are studied: single harmonic, bunch shortening and bunch lengthening. It is shown that every RF configuration may be preferable, depending on the bunch emittance and intensity.

  10. 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

  11. Longitudinal changes in lung hyperinflation in COPD

    PubMed Central

    Park, Jimyung; Lee, Chang-Hoon; Lee, Yeon Joo; Park, Jong Sun; Cho, Young-Jae; Lee, Jae Ho; Lee, Choon-Taek; Yoon, Ho Il

    2017-01-01

    Purpose COPD is characterized by an accelerated and progressive decline in forced expiratory volume in 1 second (FEV1) and lung hyperinflation. Although lung hyperinflation is the hallmark of COPD, data on the longitudinal changes in lung hyperinflation and any association with the decline in FEV1 are lacking. The aim of this study was to evaluate the longitudinal changes in lung hyperinflation and to investigate its relationship with FEV1 decline. Patients and methods We conducted a prospective cohort study and studied 176 COPD patients with annual lung volume measurements over a period of 5 years or more. We used a random coefficient model to calculate the annual changes in lung volumes and to evaluate the factors associated with changes in lung hyperinflation. Additionally, the relationship between the change in lung hyperinflation and FEV1 was assessed. Results Residual volume (RV), inspiratory capacity (IC), and total lung capacity (TLC) declined at a mean rate of 39.5, 49.6, and 63.8 mL/year, respectively. While IC/TLC declined at 0.70%/year, RV/TLC also declined at 0.35%/year. Changes in both IC/TLC and RV/TLC varied significantly. Frequent exacerbations led to an increase in RV/TLC and faster decline in IC/TLC over time. RV/TLC declined in 59.7% and increased in 40.3% of the patients. A significant negative correlation was found between the rates of change in FEV1 and RV/TLC, and the rate of decline in FEV1 was greater in patients with an increase in RV/TLC than in those with a decline in RV/TLC (54.2 vs 10.7 mL/year, P<0.001). Conclusion The rate of change in lung hyperinflation varied greatly among COPD patients. Progression of hyperinflation was associated with frequent exacerbations and a faster decline in FEV1. PMID:28223790

  12. Longitudinal gradients along a reservoir cascade

    USGS Publications Warehouse

    Miranda, L.E.; Habrat, M.D.; Miyazono, S.

    2008-01-01

    Reservoirs have traditionally been regarded as spatially independent entities rather than as longitudinal segments of a river system that are connected upstream and downstream to the river and other reservoirs. This view has frustrated advancement in reservoir science by impeding adequate organization of available information and by hindering interchanges with allied disciplines that often consider impounded rivers at the basin scale. We analyzed reservoir morphology, water quality, and fish assemblage data collected in 24 reservoirs of the Tennessee River; we wanted to describe longitudinal changes occurring at the scale of the entire reservoir series (i.e., cascade) and to test the hypothesis that fish communities and environmental factors display predictable gradients like those recognized for unimpounded rivers. We used a data set collected over a 7-year period; over 3 million fish representing 94 species were included in the data set. Characteristics such as reservoir mean depth, relative size of the limnetic zone, water retention time, oxygen stratification, thermal stratification, substrate size, and water level fluctuations increased in upstream reservoirs. Conversely, reservoir area, extent of riverine and littoral zones, access to floodplains and associated wetlands, habitat diversity, and nutrient and sediment inputs increased in downstream reservoirs. Upstream reservoirs included few, largely lacustrine, ubiquitous fish taxa that were characteristic of the lentic upper reaches of the basin. Fish species richness increased in a downstream direction from 12 to 67 species/ reservoir as riverine species became more common. Considering impoundments at a basin scale by viewing them as sections in a river or links in a chain may generate insight that is not always available when the impoundments are viewed as isolated entities. Basin-scale variables are rarely controllable but constrain the expression of processes at smaller scales and can facilitate the

  13. Psychosocial adjustment to ALS: a longitudinal study.

    PubMed

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS.

  14. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS. PMID:26441696

  15. Children's food preferences: a longitudinal analysis.

    PubMed

    Skinner, Jean D; Carruth, Betty Ruth; Wendy, Bounds; Ziegler, Paula J

    2002-11-01

    To compare children's food preferences longitudinally and identify factors related to food preferences. Mothers completed the Food Preference Questionnaire for children at 2 to 3 years of age (T1), 4 years (T2), and 8 years (T3) and for themselves at T1 and T3. Both groups completed a Food Neophobia Scale at T3. 70 child/mother pairs who had participated continuously in the longitudinal study. Changes in food preferences over time were tested with paired t tests and correlations. Consistency percentages were calculated by summing the consistent matches (like/like) for each food between two time periods. Similarly, concordance percentages were calculated for child/mother pairs by summing the concordant matches for each food. General linear models were developed to identify influences on children's food preferences. Although children liked most foods, the number of liked foods did not change significantly during the 5 to 5.7 years of the study. The strongest predictors of the number of foods liked at age 8 years (R2=0.74) were the number liked at 4 years (P<.0001) and the food neophobia score (P=.0003). Newly tasted foods were more likely to be accepted between T1 and T2 than T2 and T3. Mothers' and children's food preferences were significantly but moderately related. Foods disliked by mothers tended not to be offered to children. The important role of children's early food preferences is confirmed by this study. Mothers influence children via their own preferences, which may limit foods offered to children.

  16. Distraction osteogenesis using a longitudinal corticotomy.

    PubMed

    Al-Saati, Ma'ad F; Magnussen, Robert A; Lustig, Sebastien; Testa, Rodolphe; Al-Saati, Gazal; Al-Saati, Faisal

    2012-05-01

    The purpose of this study was to evaluate whether the use of a longitudinal corticotomy (S-Z osteotomy) results in more rapid consolidation following distraction osteogenesis of short tibiae. Sixty-seven lengthening procedures were performed in 51 patients ranging in age from nine to 38 (mean 25) years. Diagnoses included short stature (32 tibiae), postpolio limb deformity (22 tibiae), osteomyelitis (three tibiae), trauma (two tibiae) and other diagnoses (eight tibiae). Forty-five lengthenings were performed via a longitudinal corticotomy, and 22 were performed via a transverse corticotomy. Patients were followed until consolidation of the regenerated bone was noted radiographically (consolidation time). The healing index (consolidation time per centimetre of lengthening) was calculated for each patient and compared between groups. The healing index was significantly lower in the S-Z group (30.8 ± 9.6 days/cm) than in the transverse corticotomy group (46.8 ± 20.2 days/cm) (p < 0.0001). Mean lengthening was 6.6 (range 2.5-12.5) cm in the S-Z group and 5.8 (range 2.0-12.0) cm in the transverse group (p = 0.28). Mean consolidation time was 6.3 ± 2.8 (range 3-16) months in the S-Z group and 8.1 ± 3.8 (range 3-13.5) months in the transverse group (p = 0.03). The S-Z osteotomy safely reduces consolidation time of regenerative bone during distraction osteogenesis in the tibia relative to a transverse corticotomy.

  17. HARVEST, a longitudinal patient record summarizer

    PubMed Central

    Hirsch, Jamie S; Tanenbaum, Jessica S; Lipsky Gorman, Sharon; Liu, Connie; Schmitz, Eric; Hashorva, Dritan; Ervits, Artem; Vawdrey, David; Sturm, Marc; Elhadad, Noémie

    2015-01-01

    Objective To describe HARVEST, a novel point-of-care patient summarization and visualization tool, and to conduct a formative evaluation study to assess its effectiveness and gather feedback for iterative improvements. Materials and methods HARVEST is a problem-based, interactive, temporal visualization of longitudinal patient records. Using scalable, distributed natural language processing and problem salience computation, the system extracts content from the patient notes and aggregates and presents information from multiple care settings. Clinical usability was assessed with physician participants using a timed, task-based chart review and questionnaire, with performance differences recorded between conditions (standard data review system and HARVEST). Results HARVEST displays patient information longitudinally using a timeline, a problem cloud as extracted from notes, and focused access to clinical documentation. Despite lack of familiarity with HARVEST, when using a task-based evaluation, performance and time-to-task completion was maintained in patient review scenarios using HARVEST alone or the standard clinical information system at our institution. Subjects reported very high satisfaction with HARVEST and interest in using the system in their daily practice. Discussion HARVEST is available for wide deployment at our institution. Evaluation provided informative feedback and directions for future improvements. Conclusions HARVEST was designed to address the unmet need for clinicians at the point of care, facilitating review of essential patient information. The deployment of HARVEST in our institution allows us to study patient record summarization as an informatics intervention in a real-world setting. It also provides an opportunity to learn how clinicians use the summarizer, enabling informed interface and content iteration and optimization to improve patient care. PMID:25352564

  18. Prospective, longitudinal assessment of developmental neurotoxicity.

    PubMed Central

    Jacobson, J L; Jacobson, S W

    1996-01-01

    Methodological issues in the design of prospective, longitudinal studies of developmental neurotoxicity in humans are reviewed. A comprehensive assessment of potential confounding influences is important in these studies because inadequate assessment of confounders can threaten the validity of causal inferences drawn from the data. Potential confounders typically include demographic background variables, alcohol and smoking during pregnancy, the quality of parental stimulation, the child's age at test, and the examiner. Exposure to other substances is assessed where significant exposure is expected in the target population. In most studies, control variables even weakly related to outcome are included in all multivariate statistical analyses, and a toxic effect is inferred only if the effect of exposure is significant after controlling for the potential confounders. Once a neurotoxic effect has been identified, suspected mediating variables may be added to the analysis to examine underlying processes or mechanisms through which the exposure may impact on developmental outcome. Individual differences in vulnerability may be examined in terms of either an additive compensatory model or a synergistic "risk and resilience" approach. Failure to detect real effects (Type II error) is of particular concern in these studies because public policy considerations make it likely that negative findings will be interpreted to mean that the exposure is safe. Important sources of Type II error include inadequate representation of highly exposed individuals, overcontrol for confounders, and inappropriate correction for multiple comparisons. Given the high cost and complexity of prospective, longitudinal investigations, cross-sectional pilot studies focusing on highly exposed individuals can be valuable for the initial identification of salient domains of impairment. PMID:9182034

  19. Dimensions of integration, continuity and longitudinality in clinical clerkships.

    PubMed

    Ellaway, Rachel H; Graves, Lisa; Cummings, Beth-Ann

    2016-09-01

    Over the past few decades, longitudinal integrated clerkships (LICs) have been proposed to address many perceived short-coming of traditional block clerkships. This growing interest in LICs has raised broader questions regarding the role of integration, continuity and longitudinality in medical education. A study with complementary theoretical and empirical dimensions was conducted to derive a more precise way of defining these three underlying concepts within the design of medical education curricula. The theoretical dimension involved a thematic review of the literature on integration, continuity and longitudinality in medical education. The empirical dimension surveyed all 17 Canadian medical schools on how they have operationalised integration, continuity and longitudinality in their undergraduate programmes. The two dimensions were iteratively synthesised to explore the meaning and expression of integration, continuity and longitudinality in medical education curriculum design. Integration, continuity and longitudinality were expressed in many ways and forms, including: integration of clinical disciplines, combined horizontal integration and vertical integration, and programme-level integration. Types of continuity included: continuity of patients, continuity of teaching, continuity of location and peer continuity. Longitudinality focused on connected or repeating episodes of training or on connecting activities, such as encounter logging across educational episodes. Twelve of the 17 schools were running an LIC of some kind, although only one school had a mandatory LIC experience. An ordinal scale of uses of integration, continuity and longitudinality during clerkships was developed, and new definitions of these concepts in the clerkship context were generated. Different clerkship designs embodied different forms and levels of integration, continuity and longitudinality. A dichotomous view of LICs and rotation-based clerkships was found not to represent

  20. Cosmic muon induced EM showers in NO$\

    SciTech Connect

    Yadav, Nitin; Duyang, Hongyue; Shanahan, Peter; Mishra, Sanjib; Bhuyan, Bipul

    2016-11-15

    Here, the NuMI Off-Axis ve Appearance (NOvA) experiment is a ne appearance neutrino oscillation experiment at Fermilab. It identifies the ne signal from the electromagnetic (EM) showers induced by the electrons in the final state of neutrino interactions. Cosmic muon induced EM showers, dominated by bremsstrahlung, are abundant in NOvA far detector. We use the Cosmic Muon- Removal technique to get pure EM shower sample from bremsstrahlung muons in data. We also use Cosmic muon decay in flight EM showers which are highly pure EM showers.The large Cosmic-EM sample can be used, as data driven method, to characterize the EM shower signature and provides valuable checks of the simulation, reconstruction, particle identification algorithm, and calibration across the NOvA detector.

  1. Longitudinal Section AA/South ElevationPreRehabilitation 2009; Longitudinal Section BB/PostRehabilitation 2010 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Longitudinal Section A-A/South Elevation-Pre-Rehabilitation 2009; Longitudinal Section B-B/Post-Rehabilitation 2010 - Gilpin's Falls Covered Bridge, Spanning North East Creek at Former (Bypassed) Section of North East Road (SR 272), North East, Cecil County, MD

  2. 78 FR 44553 - Agency Information Collection Activities; Comment Request; Early Childhood Longitudinal Study...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Agency Information Collection Activities; Comment Request; Early Childhood Longitudinal Study... notice will be considered public records. Title of Collection: Early Childhood Longitudinal Study... Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011), sponsored by the National...

  3. Correlation of the NBME advanced clinical examination in EM and the national EM M4 exams.

    PubMed

    Hiller, Katherine; Miller, Emily S; Lawson, Luan; Wald, David; Beeson, Michael; Heitz, Corey; Morrissey, Thomas; House, Joseph; Poznanski, Stacey

    2015-01-01

    Since 2011 two online, validated exams for fourth-year emergency medicine (EM) students have been available (National EM M4 Exams). In 2013 the National Board of Medical Examiners offered the Advanced Clinical Examination in Emergency Medicine (EM-ACE). All of these exams are now in widespread use; however, there are no data on how they correlate. This study evaluated the correlation between the EM-ACE exam and the National EM M4 Exams. From May 2013 to April 2014 the EM-ACE and one version of the EM M4 exam were administered sequentially to fourth-year EM students at five U.S. medical schools. Data collected included institution, gross and scaled scores and version of the EM M4 exam. We performed Pearson's correlation and random effects linear regression. 305 students took the EM-ACE and versions 1 (V1) or 2 (V2) of the EM M4 exams (281 and 24, respectively) [corrected].The mean percent correct for the exams were as follows: EM-ACE 74.9 (SD-9.82), V1 83.0 (SD-6.39), V2 78.5 (SD-7.70) [corrected]. Pearson's correlation coefficient for the V1/EM-ACE was 0.53 (0.43 scaled) and for the V2/EM-ACE was 0.58 (0.41 scaled) [corrected]. The coefficient of determination for V1/ EM-ACE was 0.73 and for V2/EM-ACE 0.71 (0.65 and .49 for scaled scores) [ERRATUM]. The R-squared values were 0.28 and 0.30 (0.18 and 0.13 scaled), respectively [corrected]. There was significant cluster effect by institution. There was moderate positive correlation of student scores on the EM-ACE exam and the National EM M4 Exams.

  4. Longitudinal phase space tomography with space charge

    NASA Astrophysics Data System (ADS)

    Hancock, S.; Lindroos, M.; Koscielniak, S.

    2000-12-01

    Tomography is now a very broad topic with a wealth of algorithms for the reconstruction of both qualitative and quantitative images. In an extension in the domain of particle accelerators, one of the simplest algorithms has been modified to take into account the nonlinearity of large-amplitude synchrotron motion. This permits the accurate reconstruction of longitudinal phase space density from one-dimensional bunch profile data. The method is a hybrid one which incorporates particle tracking. Hitherto, a very simple tracking algorithm has been employed because only a brief span of measured profile data is required to build a snapshot of phase space. This is one of the strengths of the method, as tracking for relatively few turns relaxes the precision to which input machine parameters need to be known. The recent addition of longitudinal space charge considerations as an optional refinement of the code is described. Simplicity suggested an approach based on the derivative of bunch shape with the properties of the vacuum chamber parametrized by a single value of distributed reactive impedance and by a geometrical coupling coefficient. This is sufficient to model the dominant collective effects in machines of low to moderate energy. In contrast to simulation codes, binning is not an issue since the profiles to be differentiated are measured ones. The program is written in Fortran 90 with high-performance Fortran extensions for parallel processing. A major effort has been made to identify and remove execution bottlenecks, for example, by reducing floating-point calculations and recoding slow intrinsic functions. A pointerlike mechanism which avoids the problems associated with pointers and parallel processing has been implemented. This is required to handle the large, sparse matrices that the algorithm employs. Results obtained with and without the inclusion of space charge are presented and compared for proton beams in the CERN protron synchrotron booster. Comparisons

  5. Longitudinal determinants of substance use disorders.

    PubMed

    Brook, Judith S; Lee, Jung Yeon; Rubenstone, Elizabeth; Finch, Stephen J; Seltzer, Nathan; Brook, David W

    2013-12-01

    Substance use and substance use disorders (SUDs) have been linked with marital discord. Relatively little is known, however, about the antecedents of SUDs, the mediators of these factors over time, or their associations with the spousal/partner relationship among urban adults. A better understanding of the longitudinal pathways to marital conflict and to SUDs should help prevention and intervention programs target their precursors within the developmental period in which they occur. The present study, therefore, examined the longitudinal predictors of an unsupportive spousal/partner relationship and SUDs among a community sample of urban African American and Puerto Rican adults from East Harlem, NY. Participants (N = 816) completed structured questionnaires at five time waves, from adolescence to adulthood (mean ages = 14, 19, 24, 29, and 32 years). Structural equation modeling examined the effects of earlier environmental and social stressors and intrapersonal and interpersonal factors on later SUDs in adulthood. There was a good fit of the structural equation model (CFI = 0.91; RMSEA = 0.06; and SRMR = 0.06), which revealed three main pathways from adolescence to the spousal/partner relationship and SUDs in adulthood. One pathway linked a weak parent-adolescent attachment relationship with the participant's psychological symptoms in emerging adulthood (p < 0.01), which in turn were related to affiliation with deviant and drug-using peers, also in emerging adulthood (p < 0.001). Peer deviance and drug use were associated with the participant's substance use in young adulthood (p < 0.001), which predicted both an unsupportive spousal/partner relationship (p < 0.05) and SUDs (p < 0.001) later in adulthood. Other pathways highlighted the continuity of psychological symptoms as related to both substance use in young adulthood (p < 0.001) and an unsupportive spousal/partner relationship in adulthood (p < 0.001). Findings

  6. Longitudinal static stability requirements for wing in ground effect vehicle

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Yang, Zhigang; Collu, Maurizio

    2015-06-01

    The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  7. Time Resolved Imaging of Longitudinal Modulations in Intense Beams

    NASA Astrophysics Data System (ADS)

    Tian, Kai

    2007-11-01

    The longitudinal evolution of high intensity beams is not well understood despite its importance to the success of such applications as free electron lasers and light sources, heavy ion inertial fusion, and high energy colliders. For example any amplification of current modulations in an FEL photoinjector can lead to unwanted coherent synchrotron radiation further downstream in compression chicanes or bends. A significant factor usually neglected is the coupling to the transverse dynamics which can strongly affect the longitudinal evolution. Previous experiments at the University of Maryland have revealed much about the longitudinal physics of space-charge dominated beams by monitoring the evolution of longitudinal perturbations. For the first time, experimental results are presented here which reveal the effect of longitudinal perturbations on the transverse beam distribution, with the aid of several new diagnostics that capture detailed time-resolved density images. A longitudinal modulation of the particle density is deliberately generated at the source, and its evolution is tracked downstream using a number of diagnostics such as current monitors, high-resolution energy analyzers, as well as the transverse imaging devices. The latter consist of a high-resolution 16-bit gated camera coupled with very fast emitters such as prompt optical transition radiation (OTR) from an alumina screen, or fast Phosphor screens with 3-ns time resolution. Simulations using the particle-in-cell code WARP are applied to cross-check the experimental results. These experiments and especially the comparisons to simulation represent significant progress towards understanding the longitudinal physics of intense beams.

  8. Longitudinal vibration of cracked beams under magnetic field

    NASA Astrophysics Data System (ADS)

    Güven, Uğur

    2016-12-01

    Longitudinal vibration of a cracked beam subjected to the transverse magnetic field is addressed. One dimensional wave theory is used and the crack part of the beam is modelled as by a linear spring, in this analysis. The obtained explicit solution, for clamped-free and clamped-clamped boundary conditions, is illustrated as graphically. It is generally seen that the longitudinal frequencies increase with increase of the intensity of magnetic field. However, the results of the analysis reveal that the transverse magnetic field has a more significant effect on the variation of longitudinal vibration frequency under the clamped-clamped boundary conditions.

  9. Longitudinal emittance growth due to nonlinear space charge effect

    NASA Astrophysics Data System (ADS)

    Lau, Y. Y.; Yu, Simon S.; Barnard, John J.; Seidl, Peter A.

    2012-03-01

    Emittance posts limits on the key requirements of final pulse length and spot size on target in heavy ion fusion drivers. In this paper, we show studies on the effect of nonlinear space charge on longitudinal emittance growth in the drift compression section. We perform simulations, using the 3D PIC code WARP, for a high current beam under conditions of bends and longitudinal compression. The linear growth rate for longitudinal emittance turns out to depend only on the peak line charge density, and is independent of pulse length, velocity tilt, and/or the pipe and beam size. This surprisingly simple result is confirmed by simulations and analytic calculations.

  10. Extracting longitudinal shower development information from crystal calorimetry plus tracking

    SciTech Connect

    Brown, David; Brown, D.N.; Ilic, J.; Mohanty, G.B.

    2007-11-01

    We present an approach to derive longitudinal shower development information from the longitudinally unsegmented BABAR electromagnetic calorimeter by using tracking information. Our algorithm takes advantage of the good three-dimensional tracking resolution of BABAR, which provides an independent geometric constraint on the shower as measured in the BABAR crystal calorimeter. We show that adding the derived longitudinal shower development information to standard particle identification algorithms significantly improves the low-momentum separation of pions from electrons and muons. We also verify that the energy dependence of the electromagnetic shower development we measure is consistent with the prediction of a standard electromagnetic shower model.

  11. Multiplexed multi-longitudinal mode fiber laser sensor.

    PubMed

    Huang, Long; Wang, Peng; Gao, Liang; Zhang, Tingting; Chen, Xiangfei

    2014-10-20

    A multiplexed multi-longitudinal mode fiber laser sensor system is proposed and demonstrated. By incorporating two matched wavelength division multiplexers (WDMs) and a semiconductor optical amplifier (SOA) into a fiber laser cavity, multiwavelength oscillation is established. Each wavelength corresponding to one channel of WDMs contains multi-longitudinal modes. The multiwavelength output of the laser is directed to another WDM which functions as a demultiplexer. By monitoring the longitudinal mode beat frequency generated at photodetectors following the WDM, the sensing information can be demodulated. Preliminary results for multiplexing two sensors measuring strain and temperature are presented to verify the principle of the system.

  12. Signal processing for longitudinal parameters of the Tevatron beam

    SciTech Connect

    Pordes, S.; Crisp, J.; Fellenz, B.; Flora, R.; Para, A.; Tollestrup, A.V.; /Fermilab

    2005-05-01

    We describe the system known as the Tevatron SBD [1] which is used to provide information on the longitudinal parameters of coalesced beam bunches in the Tevatron. The system has been upgraded over the past year with a new digitizer and improved software. The quantities provided for each proton and antiproton bunch include the intensity, the longitudinal bunch profile, the timing of the bunch with respect to the low-level RF, the momentum spread and the longitudinal emittance. The system is capable of 2 Hz operation and is run at 1 Hz.

  13. Uncorrelated Energy Spread and Longitudinal Emittance of a Photoinjector Beam

    SciTech Connect

    Huang, Z; Dowell, D.; Emma, P.; Limborg-Deprey, C.; Stupakov, G.; Wu, J.; /SLAC

    2005-05-25

    Longitudinal phase space properties of a photoinjector beam are important in many areas of high-brightness beam applications such as bunch compression, transverse-to-longitudinal emittance exchange, and high-gain free-electron lasers. In this paper, we discuss both the rf and the space charge contributions to the uncorrelated energy spread of the beam generated from a laser-driven rf gun. We compare analytical expressions for the uncorrelated energy spread and the longitudinal emittance with numerical simulations and recent experimental results.

  14. A Semiparametric Marginalized Model for Longitudinal Data with Informative Dropout.

    PubMed

    Liu, Mengling; Lu, Wenbin

    2012-01-01

    We propose a marginalized joint-modeling approach for marginal inference on the association between longitudinal responses and covariates when longitudinal measurements are subject to informative dropouts. The proposed model is motivated by the idea of linking longitudinal responses and dropout times by latent variables while focusing on marginal inferences. We develop a simple inference procedure based on a series of estimating equations, and the resulting estimators are consistent and asymptotically normal with a sandwich-type covariance matrix ready to be estimated by the usual plug-in rule. The performance of our approach is evaluated through simulations and illustrated with a renal disease data application.

  15. Complaints against an EMS system.

    PubMed

    Colwell, Christopher B; Pons, Peter T; Pi, Randy

    2003-11-01

    Complaints against Emergency Medical Services (EMS) agencies represent a concerning and potentially time-consuming problem for all involved in the delivery of prehospital emergency medical care. The objective of this study was to identify the source of complaints against an EMS system to help focus quality and performance improvement and customer service efforts. We conducted a retrospective review of complaints filed against a busy urban EMS agency over a 6-year period. All complaints were included, totaled by season and by year, and categorized by originator and nature of the complaint. A total of 286 complaints were registered during the 6-year period, with an average of 48 per year and 9.3 per 10,000 responses. The most common originators of complaints were patients (53%) followed by medical personnel (19%) and family members or friends (12%). Rude behavior accounted for 23% of the complaints registered, followed by technical skills (20%), transport problems (18%), and loss of belongings (13%). The identification of areas of dissatisfaction will allow focused quality and performance improvement programs directed at customer service and risk management.

  16. Io: longitudinal distribution of sulfur dioxide frost.

    PubMed

    1980-11-14

    Twenty spectra of Io (0.26 to 0.33 micrometer), acquired with the International Ultraviolet Explorer spacecraft, have been studied. There is a strong ultraviolet absorption shortward of 0.33 micrometer that is consistent with earlier ground-based spectrophotometry; its strength is strongly dependent on Io's rotational phase angle at the time of observation. This spectral feature and its variation are interpreted as indicative of a longitudinal variation in the distribution of sulfur dioxide frost on Io. The frost is most abundant at orbital longitudes 72 degrees to 137 degrees and least abundant at longitudes 250 degrees to 323 degrees . Variations in spectral reflectivity between 0.4 and 0.5 micrometer, reported in earlier ground-based spectral studies, correlate inversely with variations in reflectivity between 0.26 and 0.33 micrometer. It is concluded that this is because the Io surface component with the highest visible reflectivity (sulfur dioxide frost) has the lowest ultraviolet reflectivity. At least one other component is present and may be sulfur allotropes or alkali sulfides. This model is consistent with ground-based ultraviolet, visible, and infrared spectrophotometry. Comparison with Voyager color photographs indicates that the sulfur dioxide frost is in greatest concentration in the "white" areas on Io and the other sulfurous components are in greatest concentration in the "red" areas.

  17. Longitudinal Relationships Between Resources, Motivation, and Functioning

    PubMed Central

    Emery, Lisa; Neupert, Shevaun D.

    2012-01-01

    Objectives. We investigated how fluctuations and linear changes in health and cognitive resources influence the motivation to engage in complex cognitive activity and the extent to which motivation mediated the relationship between changing resources and cognitively demanding activities. Method. Longitudinal data from 332 adults aged 20–85 years were examined. Motivation was assessed using a composite of Need for Cognition and Personal Need for Structure and additional measures of health, sensory functioning, cognitive ability, and self-reported activity engagement. Results. Multilevel modeling revealed that age-typical changes in health, sensory functions, and ability were associated with changes in motivation, with the impact of declining health on motivation being particularly strong in older adulthood. Changes in motivation, in turn, predicted involvement in cognitive and social activities as well as changes in cognitive ability. Finally, motivation was observed to partially mediate the relationship between changes in resources and cognitively demanding activities. Discussion. Our results suggest that motivation may play an important role in determining the course of cognitive change and involvement in cognitively demanding everyday activities in adulthood. PMID:21926400

  18. Longitudinal validation of psychosis risk screening tools.

    PubMed

    Kline, Emily; Thompson, Elizabeth; Demro, Caroline; Bussell, Kristin; Reeves, Gloria; Schiffman, Jason

    2015-07-01

    The development of widely used interview tools has helped to standardize the criteria for a "clinical high risk" syndrome, thus enabling advances in efforts to develop interventions for this phase of illness. These assessments, however, are burdensome to administer and not likely to be adopted for widespread use. Scalable early intervention depends on the availability of brief, low-cost assessment tools that can serve to screen populations of interest or triage treatment-seekers toward specialized care. The current study examines the sensitivity, specificity, and predictive strength of three self-report measures (Prime Screen-Revised, Prodromal Questionnaire-Brief, and Youth Psychosis at Risk Questionnaire-Brief) with regard to psychosis onset and symptom persistence over six months of follow-up within an indicated sample of 54 adolescents and young adults ages 12-22. Within this sample, all three measures demonstrated excellent sensitivity to emerging psychosis and strong agreement with clinician evaluations of attenuated psychosis symptoms. Additionally, all screeners obtained negative predictive values of 1.00 with regard to psychosis onset, indicating that an individual scoring below the recommended threshold score would be extremely unlikely to develop psychosis over the following six months. The longitudinal validation of psychosis risk screening tools constitutes an important step toward establishing a standard of care for early identification and monitoring in this vulnerable population.

  19. SORL1 predicts longitudinal cognitive change

    PubMed Central

    Reynolds, Chandra A.; Zavala, Catalina; Gatz, Margaret; Vie, Loryana; Johansson, Boo; Malmberg, Bo; Ingelsson, Erik; Prince, Jonathan A.; Pedersen, Nancy L.

    2013-01-01

    The gene encoding sortilin receptor 1 (SORL1) has been associated with Alzheimer’s disease risk. We examined 15 SORL1 variants and SNP-set risk scores in relation to longitudinal verbal, spatial, memory and perceptual speed performance, testing for age trends and sex-specific effects. Altogether, 1609 individuals from three population-based Swedish twin studies were assessed up to five times across 16 years. Controlling for APOE, multiple simple and sex-moderated associations were observed for spatial, episodic memory and verbal trajectories (p = 1.25E-03 to p = 4.83E-02). Five variants (rs11600875, rs753780, rs7105365, rs11820794, rs2070045) were associated across domains. Notably, in those homozygous for rs2070045 risk alleles, males demonstrated initially favorable performance but accelerating declines, while females showed overall lower performance. SNP-set risk scores predicted spatial (Card Rotations, p = 5.92E-03) and episodic memory trajectories (Thurstone Picture Memory, p = 3.34E-02), where higher risk scores benefitted men’s versus women’s performance up to age 75 but with accelerating declines. SORL1 is associated with cognitive aging, and may contribute differentially to change in men and women. PMID:23318115

  20. Longitudinal maxillary growth in Down syndrome patients.

    PubMed

    Alió, Juan; Lorenzo, José; Iglesias, M Carmen; Manso, Francisco J; Ramírez, Eva M

    2011-03-01

    To assess maxillary growth in a sample of patients diagnosed with Down syndrome (DS). The sample comprised 47 subjects (25 boys, 22 girls) with DS. All patients had at least two radiographs that showed the cranial base. To obtain comparisons among age groups, the sample was divided into three groups: prepubescent (8-11 years old), pubescent (12-14 years old), and postpubescent (15-18 years old). A control group included 38 subjects without DS (22 boys, 16 girls) who were part of a longitudinal growth sample. Computerized cephalometric analysis was performed on all subjects, and cephalometric superimpositions were made. Two-way analysis of variance (ANOVA) was used to study the overall changes between groups. In addition, one-way ANOVA and the Duncan multiple-range test were used to analyze possible differences in the age groups. Sagittal maxillary growth in DS patients was constant from the age of 8 to 18 years; there was an average increase of 0.12 mm/year, measured at the level of point A. In the vertical plane it grows at an average rate of 0.62 mm/year and 0.70 mm/year, measured at the level of the ANS and PNS, respectively. The maxilla in the DS group shows hypoplasia in the vertical plane and the sagittal plane, and there was a mean deficit of almost 10 mm in the latter.

  1. Longitudinal performance of an implantable vestibular prosthesis

    PubMed Central

    Phillips, Christopher; Ling, Leo; Oxford, Trey; Nowack, Amy; Nie, Kaibao; Rubinstein, Jay T.; Phillips, James O.

    2014-01-01

    Loss of vestibular function may be treatable with an implantable vestibular prosthesis that stimulates semicircular canal afferents with biphasic pulse trains. Several studies have demonstrated short-term activation of the vestibulo-ocular reflex (VOR) with electrical stimulation. Fewer long-term studies have been restricted to small numbers of animals and stimulation designed to produce adaptive changes in the electrically elicited response. This study is the first large consecutive series of implanted rhesus macaque to be studied longitudinally using brief stimuli designed to limit adaptive changes in response, so that the efficacy of electrical activation can be studied over time, across surgeries, canals and animals. The implantation of a vestibular prosthesis in animals with intact vestibular end organs produces variable responses to electrical stimulation across canals and animals, which change in threshold for electrical activation of eye movements and in elicited slow phase velocities over time. These thresholds are consistently lower, and the slow phase velocities higher, than those obtained in human subjects. The changes do not appear to be correlated with changes in electrode impedance. The variability in response suggests that empirically derived transfer functions may be required to optimize the response of individual canals to a vestibular prosthesis, and that this function may need to be remapped over time. PMID:25245586

  2. Adolescent stress and coping: a longitudinal study.

    PubMed

    Groër, M W; Thomas, S P; Shoffner, D

    1992-06-01

    The purpose of this longitudinal panel study was to investigate developmental and gender influences on stress and coping in adolescents attending a suburban high school in Tennessee. Data were collected from the same 167 subjects during the freshman year and again during the senior year. Life events stress was measured through the Adolescent Life Change Event Scale (ALCES) and ways of coping were categorized from data gathered from an open-ended questionnaire. Girls reported more life events stress at both testings than boys. Life events stress was greater at senior testing for both girls and boys, but girls' scores increased more. The "gender intensification" phenomenon may account for the greater disparity in types of stress reported by boys and girls as seniors. Girls generally reported more life events associated with interpersonal and family relationships. Both girls and boys reported coping with stress mostly through active distraction techniques such as exercise. However, girls' use of active distraction decreased over time, while passive distraction increased. Self-destructive and aggressive coping behaviors increased for boys. There were no relationships between amounts or types of life events stress and ways of coping for subjects at either time.

  3. [Prematurity: longitudinal analysis of executive functions].

    PubMed

    Sastre-Riba, S

    2009-02-27

    Understanding cognitive development requires an interdisciplinary and neuropsychological approach. Executive functions facilitates cognitive activity and they are related to progressive cerebral configuration during pregnancy and infancy. One of the aims of the actual neuropsychology is the ontogeny of executive functions and their capacity to explain differential and normative developmental trends, specially because of its consequences on mental flexibility, monitoring, planning and cognitive control; they are also essential for good performance at school. The incidence of developmental risk factors as prematurity could affect long-term executive functioning expressed in learning difficulties or behavioral control. We studied, comparatively and longitudinally, the individual activity on objects displayed by typical babies (n = 25), and preterm babies (n = 10) from 1.5 to 2 years-old. Applying systematic observational methodology, spontaneous babies' activity is registered. Double intra and inter-group analysis compare the data from the resolution of a non-verbal task through a multifaceted design. Results obtained show us differential pattern of early executive functioning among the groups studied. The growth of executive functioning is showed, too, through the ages studied for every group.

  4. Longitudinal dynamic stability of a shuttle vehicle.

    NASA Technical Reports Server (NTRS)

    Vinh, N. X.; Laitone, E. V.

    1972-01-01

    Analytical study of the longitudinal dynamic stability of a nonrolling, lifting vehicle gliding at hypersonic speeds. The analysis applies to shuttle vehicles designed for operating up to the rim of a planetary atmosphere. A general nondimensional time transformation is introduced to derive a unified second-order linear differential equation for the angle of attack, valid for all types of reentry of a general type of vehicle. The stability of motion is discussed for two fundamental regimes of flight that are based on widely different assumptions. For near ballistic entry along a straight line trajectory, the equation reduces to a confluent hypergeometric equation, the solution of which can be expressed in terms of Whittaker's function. Using a theorem in the theory of stability of differential equations, criteria for damped oscillations are derived. It is shown that the aerodynamic criteria for stability are the same as for the case of ballistic entry. In addition, for each vehicle configuration, and specified planetary atmosphere, there exists an altitude range where the angle of attack frequency is nearly equal to the orbital frequency causing instability in pitch. This resonance instability is due to the ellipticity of the orbit. Criteria for eccentricity instability are derived.

  5. Longitudinal wheel slip during ABS braking

    NASA Astrophysics Data System (ADS)

    Hartikainen, Lassi; Petry, Frank; Westermann, Stephan

    2015-02-01

    Anti-lock braking system (ABS) braking tests with two subcompact passenger cars were performed on dry and wet asphalt, as well as on snow and ice surfaces. The operating conditions of the tyres in terms of wheel slip were evaluated using histograms of the wheel slip data. The results showed different average slip levels for different road surfaces. It was also found that changes in the tyre tread stiffness affected the slip operating range through a modification of the slip value at which the maximum longitudinal force is achieved. Variation of the tyre footprint length through modifications in the inflation pressure affected the slip operating range as well. Differences in the slip distribution between vehicles with different brake controllers were also observed. The changes in slip operating range in turn modified the relative local sliding speeds between the tyre and the road. The results highlight the importance of the ABS controller's ability to adapt to changing slip-force characteristics of tyres and provide estimates of the magnitude of the effects of different tyre and road operating conditions.

  6. Dual imputation model for incomplete longitudinal data.

    PubMed

    Jolani, Shahab; Frank, Laurence E; van Buuren, Stef

    2014-05-01

    Missing values are a practical issue in the analysis of longitudinal data. Multiple imputation (MI) is a well-known likelihood-based method that has optimal properties in terms of efficiency and consistency if the imputation model is correctly specified. Doubly robust (DR) weighing-based methods protect against misspecification bias if one of the models, but not necessarily both, for the data or the mechanism leading to missing data is correct. We propose a new imputation method that captures the simplicity of MI and protection from the DR method. This method integrates MI and DR to protect against misspecification of the imputation model under a missing at random assumption. Our method avoids analytical complications of missing data particularly in multivariate settings, and is easy to implement in standard statistical packages. Moreover, the proposed method works very well with an intermittent pattern of missingness when other DR methods can not be used. Simulation experiments show that the proposed approach achieves improved performance when one of the models is correct. The method is applied to data from the fireworks disaster study, a randomized clinical trial comparing therapies in disaster-exposed children. We conclude that the new method increases the robustness of imputations.

  7. Longitudinal Waves Organize and Control Plants

    NASA Astrophysics Data System (ADS)

    Wagner, Orvin

    2002-03-01

    Since the discovery of longitudinal waves in plants (W-waves)in 1988 I have taken data related to influences of these waves. These data include spacings betweenstructures on plants,sap flow data, electrical data from probes traceable to effects produced by these waves, data related to the influences of gravity, data related to these waves traveling between plants and on and on. All of the data suggest that the waves provide a basis for a unified theory for plant growth and development. They likely provide a basis for growth and development for all life. The wave influences are present on the microscopic level in live plants but may not show in the microscopic pieces of material often scrutinized by the usual researcher. It is this author's conclusion that the waves mentioned are important in all life and provide what we call life which has been so difficult to pinpoint in previous work. The waves show in dead material but generally are of a much smaller amplitude in the resonating live material. In the wave theory one might compare something alive to a properly operating laser. See the Wagner web site.

  8. Automatic parcellation of longitudinal cortical surfaces

    NASA Astrophysics Data System (ADS)

    Alassaf, Manal H.; Hahn, James K.

    2015-03-01

    We present a novel automatic method to parcellate the cortical surfaces of the neonatal brain longitudinal atlas at different stages of development. A labeled brain atlas of newborn at 41 weeks gestational age (GA) is used to propagate labels of anatomical regions of interest to an unlabeled spatio-temporal atlas, which provides a dynamic model of brain development at each week between 28-44 GA weeks. First, labels from the cortical volume of the labeled newborn brain are propagated to an age-matched cortical surface from the spatio-temporal atlas. Then, labels are propagated across the cortical surfaces of each week of the spatio-temporal atlas by registering successive cortical surfaces using a novel approach and an energy optimization function. This procedure incorporates local and global, spatial and temporal information when assigning the labels to each surface. The result is a complete parcellation of 17 neonatal brain surfaces of the spatio-temporal atlas with similar points per labels distributions across weeks.

  9. NASA Planetary Science Summer School: Longitudinal Study

    NASA Astrophysics Data System (ADS)

    Giron, Jennie M.; Sohus, A.

    2006-12-01

    NASA’s Planetary Science Summer School is a program designed to prepare the next generation of scientists and engineers to participate in future missions of solar system exploration. The opportunity is advertised to science and engineering post-doctoral and graduate students with a strong interest in careers in planetary exploration. Preference is given to U.S. citizens. The “school” consists of a one-week intensive team exercise learning the process of developing a robotic mission concept into reality through concurrent engineering, working with JPL’s Advanced Project Design Team (Team X). This program benefits the students by providing them with skills, knowledge and the experience of collaborating with a concept mission design. A longitudinal study was conducted to assess the impact of the program on the past participants of the program. Data collected included their current contact information, if they are currently part of the planetary exploration community, if participation in the program contributed to any career choices, if the program benefited their career paths, etc. Approximately 37% of 250 past participants responded to the online survey. Of these, 83% indicated that they are actively involved in planetary exploration or aerospace in general; 78% said they had been able to apply what they learned in the program to their current job or professional career; 100% said they would recommend this program to a colleague.

  10. Analysis of critically refracted longitudinal waves

    NASA Astrophysics Data System (ADS)

    Pei, Ning; Bond, Leonard J.

    2015-03-01

    Fabrication processes, such as, welding, forging, and rolling can induce residual stresses in metals that will impact product performance and phenomena such as cracking and corrosion. To better manage residual stress tools are needed to map their distribution. The critically refracted ultrasonic longitudinal (LCR) wave is one such approach that has been used for residual stress characterization. It has been shown to be sensitive to stress and less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a numerical model used to investigate the transducers' parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal test method is used to study the transducer parameters which influence the LCR wave beams. This method provides a design tool that can be used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The simulation of the sound field in a 2-D "water-steel" model is obtained using a Spatial Fourier Analysis method. The effects of incident angle, standoff, the aperture and the center frequency of the transducer were studied. Results show that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields.

  11. Analysis of critically refracted longitudinal waves

    SciTech Connect

    Pei, Ning Bond, Leonard J.

    2015-03-31

    Fabrication processes, such as, welding, forging, and rolling can induce residual stresses in metals that will impact product performance and phenomena such as cracking and corrosion. To better manage residual stress tools are needed to map their distribution. The critically refracted ultrasonic longitudinal (LCR) wave is one such approach that has been used for residual stress characterization. It has been shown to be sensitive to stress and less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a numerical model used to investigate the transducers' parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal test method is used to study the transducer parameters which influence the LCR wave beams. This method provides a design tool that can be used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The simulation of the sound field in a 2-D 'water-steel' model is obtained using a Spatial Fourier Analysis method. The effects of incident angle, standoff, the aperture and the center frequency of the transducer were studied. Results show that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields.

  12. Heat transfer in a longitudinal glow discharge

    NASA Astrophysics Data System (ADS)

    Yunusov, R. F.

    2017-01-01

    This article is devoted to the experimental study of heat transfer in a longitudinal glow discharge. The discharge was ignited in the discharge chamber (DC), consisting of a glass tube 10 mm in diameter and two electrodes. Copper electrodes were placed in the side branches, so that the average distance between them was 9 cm. The discharge pressure was varied in the range of P = (2.5 – 8.5) kPa. The air flow rate was varied from zero to G = 0.06 g / s. Current was varied in the range of I = (30-80) mA. Current-voltage characteristics of the discharge had falling form, and the voltage was varied in the range of U = (1-2) kV. The temperature of neutral particles in the plasma glow discharge was measured by six thermocouples, which were insertedon radius of DC. The aim of the article was to compare achieved experiment data with theoretical studies: recombination and diffusion plasma models.

  13. Semiparametric Bayesian classification with longitudinal markers

    PubMed Central

    De la Cruz-Mesía, Rolando; Quintana, Fernando A.; Müller, Peter

    2013-01-01

    Summary We analyse data from a study involving 173 pregnant women. The data are observed values of the β human chorionic gonadotropin hormone measured during the first 80 days of gestational age, including from one up to six longitudinal responses for each woman. The main objective in this study is to predict normal versus abnormal pregnancy outcomes from data that are available at the early stages of pregnancy. We achieve the desired classification with a semiparametric hierarchical model. Specifically, we consider a Dirichlet process mixture prior for the distribution of the random effects in each group. The unknown random-effects distributions are allowed to vary across groups but are made dependent by using a design vector to select different features of a single underlying random probability measure. The resulting model is an extension of the dependent Dirichlet process model, with an additional probability model for group classification. The model is shown to perform better than an alternative model which is based on independent Dirichlet processes for the groups. Relevant posterior distributions are summarized by using Markov chain Monte Carlo methods. PMID:24368871

  14. Longitudinal dynamics of a perching aircraft concept

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim; Waszak, Martin

    2005-05-01

    This paper introduces a morphing aircraft concept whose purpose is to demonstrate a new bio-inspired flight capability: perching. Perching is a maneuver that utilizes primarily aerodynamics -- as opposed to thrust generation -- to achieve a vertical or short landing. The flight vehicle that will accomplish this is described herein with particular emphasis on its addition levels of actuation beyond the traditional aircraft control surfaces. A computer model of the aircraft is developed in order to predict the changes in applied aerodynamic loads as it morphs and transitions through different flight regimes. The analysis of this model is outlined, including a lifting-line-based analytical technique and a trim and stability analysis. These analytical methods -- compared to panel or computational fluid dynamics (CFD) methods -- are considered desirable for the analysis of a large number of vehicle configurations and flight conditions. The longitudinal dynamics of this aircraft are studied, and several interesting results are presented. Of special interest are the changes in vehicle dynamics as the aircraft morphs from a cruise configuration to initiate the perching maneuver. Changes in trim conditions and stability are examined as functions of vehicle geometry. The time response to changes in vehicle configuration is also presented.

  15. Longitudinal growth in chronic hypokalemic disorders.

    PubMed

    Gil-Peña, Helena; Mejia, Natalia; Alvarez-Garcia, Oscar; Loredo, Vanessa; Santos, Fernando

    2010-04-01

    Growth retardation remains a major complication in children with primary tubular disorders, despite adequate supplemental treatment with electrolytes, water and bicarbonate. Chronic hypokalemia, characteristic of some tubulopathies, impairs growth by mechanisms that are not well known. Association with growth hormone deficiency has been reported in patients with Bartter's or Gitelman's syndrome. Tissue-specific alterations of growth hormone and insulin-like growth factor I axis have been described in experimental models of potassium depletion. Hypokalemic rats gain less body length and weight than pair-fed normokalemic animals and, by contrast, develop renal hypertrophy. These rats have low circulating concentrations of insulin-like growth factor I, depressed messenger ribonucleic acid (mRNA) levels of this peptide in the tibial growth plate, and they are resistant to the longitudinal growth-promoting effects of exogenous growth hormone. The reason for this resistance remains to be defined. No alterations in the intracellular signaling for growth hormone have been found in the liver of hypokalemic rats. However, treatment with high doses of growth hormone is unable to normalize hypertrophy of the epiphyseal cartilage chondrocytes, which are severely disturbed in potassium depletion and likely play an important role in the pathogenia of growth impairment in this condition.

  16. Cuba's Aging and Alzheimer Longitudinal Study.

    PubMed

    Llibre-Rodríguez, Juan de Jesús; Valhuerdi-Cepero, Adolfo; López-Medina, Ana M; Noriega-Fernández, Lisseth; Porto-Álvarez, Rutbeskia; Guerra-Hernández, Milagros A; Bosch-Bayard, Rodolfo I; Zayas-Llerena, Tania; Hernandez-Ulloa, Elaine; Rodríguez-Blanco, Ana L; Salazar-Pérez, Enrique; Llibre-Guerra, Juan C; Llibre-Guerra, Jorge J; Marcheco-Teruel, Beatriz

    2017-01-01

    Aging and Alzheimer is a prospective, longitudinal cohort study involving 2944 adults aged ≥65 years from selected areas in Cuba's Havana and Matanzas Provinces. This door-to-door study, which began in 2003, includes periodic assessments of the cohort based on an interview; physical exam; anthropometric measurements; and diagnosis of dementia and its subtypes, other mental disorders, and other chronic non-communicable diseases and their risk factors. Information was gathered on sociodemographic characteristics; disability, dependency and frailty; use of health services; and characteristics of care and caregiver burden. The first assessment also included blood tests: complete blood count, blood glucose, kidney and liver function, lipid profile and ApoE4 genotype (a susceptibility marker). In 2007-2011, the second assessment was done of 2010 study subjects aged ≥65 years who were still alive. The study provides data on prevalence and incidence of dementia and its risk factors, and of related conditions that affect the health of older adults. It also contributes valuable experiences from field work and interactions with older adults and their families. Building on lessons learned, a third assessment to be done in 2016-2018 will incorporate a community intervention strategy to respond to diseases and conditions that predispose to dementia, frailty and dependency in older adults. KEYWORDS Dementia, Alzheimer disease, chronic disease, aging, chronic illness, frailty, dependency, cohort studies, Cuba.

  17. Personality and Smoking Status: A Longitudinal Analysis

    PubMed Central

    Munafó, Marcus R.; Black, Stephanie

    2007-01-01

    We attempted to clarify the strength and nature of the association between personality and smoking status in early and middle adulthood, using a longitudinal study design. Data from the Medical Research Council National Survey of Health and Development, based on a stratified sample of all single, legitimate births occurring in England, Wales, and Scotland in one week of March 1946 (N=5,362), were analyzed using generalized estimating equations methods to account for the correlation between the smoking status variables for the same individual over time. The unadjusted estimates indicated that the odds of being a current smoker increased with higher personality score for both extraversion (p<.0001) and neuroticism (p<.0001) traits. Sex was significantly associated with being a current smoker (p<.0001), with males more likely than females to be current smokers. Current smoking decreased with increasing age (p<.0001). These relationships were maintained in the fully adjusted model. These data indicate that both higher levels of extraversion and higher levels of neuroticism, as measured at age 16, are independently associated with an increased likelihood of subsequently being a current smoker rather than a nonsmoker at all time points, although the observed effect sizes were small. Males also were more likely than females to be current smokers, and increasing age reduced the likelihood of being a current smoker, which is consistent with an attempt by a subset of smokers in the cohort to subsequently stop smoking. PMID:17365771

  18. Longitudinal variability of black carbon vertical profiles

    NASA Astrophysics Data System (ADS)

    Schwarz, J. P.; Weinzierl, B.; Samset, B. H.; Perring, A. E.; Dollner, M.; Heimerl, K.; Markovic, M. Z.; Ziemba, L. D.

    2015-12-01

    Black carbon (BC) aerosol contributes substantially to both climate forcing and climate forcing uncertainty. An important source of this uncertainty derives from the difficulty in predicting BC's global abundance and vertical distribution. Here we present a multi-year record of black carbon (BC) vertical concentration profiles from both sides of the Atlantic, obtained from airborne Single Particle Soot Photometers (SP2s) flown on the NASA DC-8, and the DLR Falcon research aircraft from the CONCERT, ACCESS, DC3, SEAC4RS, and SALTRACE campaigns. The measurements constrain the relative rates of BC transport/removal from, and zonal mixing in, the upper troposphere, as well as the range of BC loadings in these regions. They also constrain the time-rates of change of BC loads in altitudes at which it is a highly efficient (although sparse) climate forcer, and a relatively long-lived aerosol tracer. We find that concentration of BC in the upper troposphere can vary by a factor 10. Over the Northern mid-latitudes concentrations are however consistent to a fraction of this range over wide longitudinal ranges, over month-long timescales. The data show that BC becomes zonally mixed here starting at 500 hPa and extending to near the tropopause. These results imply broader value than previously associated with measured vertical profiles in constraining global scale BC loadings aloft.

  19. Sortilin receptor 1 predicts longitudinal cognitive change.

    PubMed

    Reynolds, Chandra A; Zavala, Catalina; Gatz, Margaret; Vie, Loryana; Johansson, Boo; Malmberg, Bo; Ingelsson, Erik; Prince, Jonathan A; Pedersen, Nancy L

    2013-06-01

    The gene encoding sortilin receptor 1 (SORL1) has been associated with Alzheimer's disease risk. We examined 15 SORL1 variants and single nucleotide polymorphism (SNP) set risk scores in relation to longitudinal verbal, spatial, memory, and perceptual speed performance, testing for age trends and sex-specific effects. Altogether, 1609 individuals from 3 population-based Swedish twin studies were assessed up to 5 times across 16 years. Controlling for apolipoprotein E genotype (APOE), multiple simple and sex-moderated associations were observed for spatial, episodic memory, and verbal trajectories (p = 1.25E-03 to p = 4.83E-02). Five variants (rs11600875, rs753780, rs7105365, rs11820794, rs2070045) were associated across domains. Notably, in those homozygous for the rs2070045 risk allele, men demonstrated initially favorable performance but accelerating declines, and women showed overall lower performance. SNP set risk scores predicted spatial (Card Rotations, p = 5.92E-03) and episodic memory trajectories (Thurstone Picture Memory, p = 3.34E-02), where higher risk scores benefited men's versus women's performance up to age 75 but with accelerating declines. SORL1 is associated with cognitive aging, and might contribute differentially to change in men and women. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Laser Wakefield diagnostic using holographic longitudinal interferometry

    SciTech Connect

    Volfbeyn, P.; Esarey, E.; Leemans, W.P.

    1999-03-26

    We propose a diagnostic technique for wakefield measurement in plasma channels. A new technique for plasma channel creation, the Ignitor Heater scheme was proposed and experimentally tested in hydrogen and nitrogen previously. It makes use of two laser pulses. The Ignitor, an ultrashort (sub 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used to heat the existing spark via in-verse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. Laser pulses injected into such plasma channels produce a plasma wake that has a phase velocity close to the speed of light. A discussion of plasma wake measurements, using a Longitudinal Interferometry Wakefield Diagnostic Based on Time Domain Rayleigh Refractometry with Holographic Inversion, will be presented.

  1. Longitudinal performance of an implantable vestibular prosthesis.

    PubMed

    Phillips, Christopher; Ling, Leo; Oxford, Trey; Nowack, Amy; Nie, Kaibao; Rubinstein, Jay T; Phillips, James O

    2015-04-01

    Loss of vestibular function may be treatable with an implantable vestibular prosthesis that stimulates semicircular canal afferents with biphasic pulse trains. Several studies have demonstrated short-term activation of the vestibulo-ocular reflex (VOR) with electrical stimulation. Fewer long-term studies have been restricted to small numbers of animals and stimulation designed to produce adaptive changes in the electrically elicited response. This study is the first large consecutive series of implanted rhesus macaque to be studied longitudinally using brief stimuli designed to limit adaptive changes in response, so that the efficacy of electrical activation can be studied over time, across surgeries, canals and animals. The implantation of a vestibular prosthesis in animals with intact vestibular end organs produces variable responses to electrical stimulation across canals and animals, which change in threshold for electrical activation of eye movements and in elicited slow phase velocities over time. These thresholds are consistently lower, and the slow phase velocities higher, than those obtained in human subjects. The changes do not appear to be correlated with changes in electrode impedance. The variability in response suggests that empirically derived transfer functions may be required to optimize the response of individual canals to a vestibular prosthesis, and that this function may need to be remapped over time. This article is part of a Special Issue entitled .

  2. Longitudinal quantile regression in the presence of informative dropout through longitudinal-survival joint modeling.

    PubMed

    Farcomeni, Alessio; Viviani, Sara

    2015-03-30

    We propose a joint model for a time-to-event outcome and a quantile of a continuous response repeatedly measured over time. The quantile and survival processes are associated via shared latent and manifest variables. Our joint model provides a flexible approach to handle informative dropout in quantile regression. A Monte Carlo expectation maximization strategy based on importance sampling is proposed, which is directly applicable under any distributional assumption for the longitudinal outcome and random effects. We consider both parametric and nonparametric assumptions for the baseline hazard. We illustrate through a simulation study and an application to an original data set about dilated cardiomyopathies.

  3. Medial Longitudinal Arch Development of Children Aged 7 to 9 Years: Longitudinal Investigation.

    PubMed

    Tong, Jasper W K; Kong, Pui W

    2016-08-01

    It is unclear at what age the medial longitudinal arch (MLA) of the foot becomes stable in children. The influence of footwear on MLA development also is unknown. The purpose of this study was to examine the MLA development of children using a longitudinal approach. The relationship between wearing different types of footwear and MLA development also was explored longitudinally. This was a longitudinal cohort observational study. The MLA of 111 healthy children (mean age=6.9 years, SD=0.3) was evaluated using 3 parameters (arch index [AI], midfoot peak pressure [PP], and maximum force [MF]) extracted from dynamic foot loading measurements at baseline (t0), 10-month follow-up (t1), and 22-month follow-up (t2). Information on footwear usage was surveyed. Linear mixed modeling was used to test for differences in MLA over time. The MLA of the children remained stable over time (AI: t0/t1/t2=0.25 [95% confidence interval (CI)=0.24, 0.26]/0.25 [95% CI=0.24, 0.26]/0.25 [95% CI=0.24, 0.26]; P=.95). When the children's sex was considered, the AI of boys decreased (higher arch) with age (0.26 [95% CI=0.24, 0.27]/0.25 [95% CI=0.24, 0.27]/0.25 [95% CI=0.23, 0.27]; P=.02). Boys also displayed a flatter MLA than girls at age 6.9 years (AI: mean difference=0.02 [95% CI=0.01, 0.04]; P=.02). At baseline, children who wore closed-toe shoes displayed the lowest MLA overall (AI: closed-toe shoes/sandals/slippers=0.26 [95% CI=0.24, 0.28]/0.24 [95% CI=0.23, 0.25]/0.25 [95% CI=0.24, 0.26]; P<.01). Children who used slippers at toddlers' age experienced a higher PP (flatter arch) in later childhood than those who wore sandals (mean difference=31.60 kPa [95% CI=1.44, 61.75]; post hoc P=.04). Information on the type of footwear worn was self-reported and, therefore, may be subjected to recall bias. The MLA of children remained stable from 7 to 9 years of age. The child's sex and the type of footwear worn during childhood may influence MLA development. © 2016 American Physical Therapy

  4. Cosmic muon induced EM showers in NO$$\

    DOE PAGES

    Yadav, Nitin; Duyang, Hongyue; Shanahan, Peter; ...

    2016-11-15

    Here, the NuMI Off-Axis ve Appearance (NOvA) experiment is a ne appearance neutrino oscillation experiment at Fermilab. It identifies the ne signal from the electromagnetic (EM) showers induced by the electrons in the final state of neutrino interactions. Cosmic muon induced EM showers, dominated by bremsstrahlung, are abundant in NOvA far detector. We use the Cosmic Muon- Removal technique to get pure EM shower sample from bremsstrahlung muons in data. We also use Cosmic muon decay in flight EM showers which are highly pure EM showers.The large Cosmic-EM sample can be used, as data driven method, to characterize the EMmore » shower signature and provides valuable checks of the simulation, reconstruction, particle identification algorithm, and calibration across the NOvA detector.« less

  5. The Empathic Operating System (emOS)

    DTIC Science & Technology

    2016-06-15

    The Empathic Operating System ( emOS ) Physiological measurements have typically been limited to expensive and cumbersome clinical research equipment...Report: The Empathic Operating System ( emOS ) Report Title Physiological measurements have typically been limited to expensive and cumbersome clinical...C-0043 Proposal number: 62850-LS-DRP Project title: “The Empathic Operating System ( emOS )” Contract performance period: January 1, 2016 – April 7

  6. Introduction to longitudinal data analysis in psychiatric research.

    PubMed

    Liu, Xian

    2015-08-25

    The onset, course, and management of mental health problems typically occur over relatively long periods of time, so a substantial proportion of psychiatric research - particularly the research that can provide clear answers about the complex interaction of biological, psychological, and social factors - requires multiple assessments of individuals and the environments in which they live over time. However, many psychiatric researchers use incorrect statistical methods to analyze this type of longitudinal data, a problem that can result in unrecognized bias in analytic results and, thus, incorrect conclusions. This paper provides an introduction to the topic of longitudinal data analysis. It discusses the different dataset structures used in the analysis of longitudinal data, the classification and management of missing data, and methods of adjusting for intra-individual correlation when developing multivariate regression models using longitudinal data.

  7. Longitudinal Stability of Person Characteristics: Intelligence and Creativity.

    ERIC Educational Resources Information Center

    Magnusson, D.; Backteman, G.

    1979-01-01

    A longitudinal study of approximately 1,000 students aged 10-16 showed high stability of intelligence and creativity. Stability coefficients for intelligence were higher than those for creativity. Results supported the construct validity of creativity. (MH)

  8. Coupling of transverse and longitudinal waves in piano strings.

    PubMed

    Etchenique, Nikki; Collin, Samantha R; Moore, Thomas R

    2015-04-01

    The existence of longitudinal waves in vibrating piano strings has been previously established, as has their importance in producing the characteristic sound of the piano. Modeling of the coupling between the transverse and longitudinal motion of strings indicates that the amplitude of the longitudinal waves are quadratically related to the transverse displacement of the string, however, experimental verification of this relationship is lacking. In the work reported here this relationship is tested by driving the transverse motion of a piano string at only two frequencies, which simplifies the task of unambiguously identifying the constituent signals. The results indicate that the generally accepted relationship between the transverse motion and the longitudinal motion is valid. It is further shown that this dependence on transverse displacement is a good approximation when a string is excited by the impact of the hammer during normal play.

  9. Room 106, A laboratory with longitudinal arrangement of benches. View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Room 106, A laboratory with longitudinal arrangement of benches. View to west. - San Bernardino Valley College, Life Science Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  10. Interactive computer program for optimal designs of longitudinal cohort studies.

    PubMed

    Tekle, Fetene B; Tan, Frans E S; Berger, Martijn P F

    2009-05-01

    Many large scale longitudinal cohort studies have been carried out or are ongoing in different fields of science. Such studies need a careful planning to obtain the desired quality of results with the available resources. In the past, a number of researches have been performed on optimal designs for longitudinal studies. However, there was no computer program yet available to help researchers to plan their longitudinal cohort design in an optimal way. A new interactive computer program for the optimization of designs of longitudinal cohort studies is therefore presented. The computer program helps users to identify the optimal cohort design with an optimal number of repeated measurements per subject and an optimal allocations of time points within a given study period. Further, users can compute the loss in relative efficiencies of any other alternative design compared to the optimal one. The computer program is described and illustrated using a practical example.

  11. 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.

  12. Optical encryption in the longitudinal domain of focused fields.

    PubMed

    Carnicer, Artur; Juvells, Ignasi; Javidi, Bahram; Martínez-Herrero, Rosario

    2016-04-04

    We develop a method for encoding information in the longitudinal component of a focused field. Focused beams display a non-zero contribution of the electric field in the direction of propagation. However, the associated irradiance is very weak and difficult to isolate from the transverse part of the beam. For these reasons, the longitudinal component of a focused field could be a good choice for encoding and securing information. Using the Richards and Wolf formalism we show how to encrypt information in the longitudinal domain of the focal area. In addition, we use quantum imaging techniques to enhance the security and to prevent unauthorized access to the information. To the best of our knowledge, this is the first report on using the longitudinal component of the focused fields in optical security.

  13. 29. HAWSER DEVICE, DEVELOPED AT WES FOR MEASURING LONGITUDINAL AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. HAWSER DEVICE, DEVELOPED AT WES FOR MEASURING LONGITUDINAL AND TRANSVERSE STRESS OF BARGES IN CANAL LOCKS. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  14. A NEW METHOD OF LONGITUDINAL DIARY ASSEMBLY FOR EXPOSURE MODELING

    EPA Science Inventory

    Many stochastic human exposure models require the construction of longitudinal time-activity diaries to evaluate the time sequence of concentrations encountered, and hence, the pollutant exposure for the simulated individuals. However, most of the available data on human activiti...

  15. New design of longitudinal ultrasonic vibrator for wire drawing

    NASA Astrophysics Data System (ADS)

    Yang, Yuancai; Yuan, Jiangbo; Liu, Shen; Shan, Xiaobiao

    2017-04-01

    This paper presents a quarter-wave longitudinal vibrator which is applied to ultrasonic assisted wire drawing. The characteristic of this vibrator is only driven by an axially polarized sandwich PZT stack, which converts electrical energy into mechanical vibration energy. The transducer and horn were designed at the same side of the nodal section to achieve greater vibration at the front of the horn. The four-terminal network method was used to design the vibrator. The finite element method (FEM) was adopted to verify the above design and used for the further analysis about the vibration performances of this vibrator. The numberial caculation results match well with the simulation results. The simulation indicates that the resonance frequency of the longitudinal vibration is about 19.6188 kHz and the amplitude of longitudinal vibration at the end of the horn is about 11.48 μm. The present work provides a new longitudinal vibrator for ultrasonic wire drawing.

  16. 8. ENGINE TEST CELL BUILDING INTERIOR. LONGITUDINAL CENTRAL PASSAGEWAY IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. ENGINE TEST CELL BUILDING INTERIOR. LONGITUDINAL CENTRAL PASSAGEWAY IN BASEMENT. LOOKING SOUTHWEST. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

  17. 3. VIEW, LOOKING SOUTHEAST, SHOWING WEST LONGITUDINAL ELEVATION OF NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW, LOOKING SOUTHEAST, SHOWING WEST LONGITUDINAL ELEVATION OF NORTH END SPAN - East Bloomsburg Bridge, Spanning Susquehanna River at Pennsylvania Route 487 (Legislative Route 283), Bloomsburg, Columbia County, PA

  18. 1. VIEW, LOOKING SOUTHWEST, SHOWING EAST LONGITUDINAL ELEVATION OF FULL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW, LOOKING SOUTHWEST, SHOWING EAST LONGITUDINAL ELEVATION OF FULL SIX SPANS - East Bloomsburg Bridge, Spanning Susquehanna River at Pennsylvania Route 487 (Legislative Route 283), Bloomsburg, Columbia County, PA

  19. 2. VIEW, LOOKING SOUTHEAST, SHOWING WEST LONGITUDINAL ELEVATION OF FULL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW, LOOKING SOUTHEAST, SHOWING WEST LONGITUDINAL ELEVATION OF FULL SIX SPANS - East Bloomsburg Bridge, Spanning Susquehanna River at Pennsylvania Route 487 (Legislative Route 283), Bloomsburg, Columbia County, PA

  20. J's Rhymes: A Longitudinal Case Study of Language Play.

    ERIC Educational Resources Information Center

    Inkelas, Sharon

    2003-01-01

    A longitudinal study of one children documents an invented language game consisting of suffixal reduplication and onset replacement. Argues that this game may more closely resemble adult rhyme. (Author/VWL)

  1. Introduction to collective instabilities----longitudinal and transverse

    SciTech Connect

    King-Yuen Ng

    1998-10-01

    These topics are covered: 1 Wakes and impedances 1.1 Wake functions 1.2 Coupling impedances 2 Longitudinal phase space 2.1 Equations of motion 2.2 Vlasov equation 3 Potential-well distortion 4 Longitudinal microwave instability 4.1 Dispersion relation 4.2 Landau damping 4.3 Self-bunching 4.4 Overshoot and bunch lengthening 4.5 Observation 5 Longitudinal coupled-bunch instabilities 5.1 Sacherer integral equation 5.2 Time domain 5.3 Rf-detuning and Robinson's stability criteria 6 Transverse instabilities 6.1 Sacherer integral equation 6.2 Solution of Sacherer integral equations 6.1 Sacherer sinusoidal modes of excitation 6.2 Chromaticity frequency shift 7 Transverse coupled-bunch instabilities 7.1 Resistive wall 7.2 Narrow resonances 8 Head-tail instabilities 9 Mode-mixing 9.1 Transverse 9.2 Longitudinal. Exercises are included.

  2. A NEW METHOD OF LONGITUDINAL DIARY ASSEMBLY FOR EXPOSURE MODELING

    EPA Science Inventory

    Many stochastic human exposure models require the construction of longitudinal time-activity diaries to evaluate the time sequence of concentrations encountered, and hence, the pollutant exposure for the simulated individuals. However, most of the available data on human activiti...

  3. Photocopy of longitudinal, cross sections and roof plan of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of longitudinal, cross sections and roof plan of the C.B. & Q. R.R. roundhouse and locomotive shops. June 1980. - Chicago, Burlington & Quincy Railroad, Roundhouse & Shops, Broadway & Spring Streets, Aurora, Kane County, IL

  4. Viability of longitudinal trenches for capturing contaminated groundwater.

    PubMed

    Hudak, Paul F

    2010-04-01

    Using a groundwater flow and mass transport model, this study compared the capability of trenches with permeable backfill for capturing hypothetical contaminant plumes in homogeneous and heterogeneous unconfined aquifers. Longitudinal (parallel to groundwater flow), as well as conventional transverse (perpendicular to groundwater flow) trench configurations were considered. Alternate trench configurations intercepted the leading tip of an initial contaminant plume and had identical length, equal to the cross-gradient width of the plume. A longitudinal trench required 31% less time than its transverse counterpart to remediate a homogeneous aquifer. By contrast, in simulated heterogeneous aquifers, longitudinal remediation timeframes ranged from 41% less to 33% more than transverse trenches. Results suggest that longitudinal trenches may be a viable alternative for narrow contaminant plumes under low-groundwater velocity conditions, but may be impractical for plumes with wide leading tips, or in complex heterogeneous aquifers with divergent flow.

  5. Longitudinal Beam Diagnostics for the ILC Injectors and Bunch Compressors

    SciTech Connect

    Piot, Philippe; Bracke, Adam; Demir, Veysel; Maxwell, Timothy; Rihaoui, Marwan; Jing, Chunguang; Power, John

    2010-12-01

    We present a diagnostics suite and analyze techniques for setting up the longitudinal beam dynamics in ILC e⁻ injectors and e⁺ and e⁻ bunch compressors. Techniques to measure the first order moments and recover the first order longitudinal transfer map of the injector's intricate bunching scheme are presented. Coherent transition radiation diagnostics needed to measure and monitor the bunch length downstream of the ~5 GeV bunch compressor are investigated using a vector diffraction model.

  6. Definition and application of longitudinal stability derivatives for elastic airplanes

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1972-01-01

    A set of longitudinal stability derivatives for elastic airplanes is defined from fundamental principles allowing perturbations in forward speed. Application of these derivatives to longitudinal stability analysis by use of approximate expressions for static stability and control parameters as well as the dynamic equations of motion is illustrated. One commonly used alternative formulation for elastic airplanes is shown to yield significant inaccuracies because of inappropriate interpretation of inertial effects.

  7. Longitudinal incision in surgical release of De Quervain disease.

    PubMed

    Gundes, Hakan; Tosun, Bilgehan

    2005-09-01

    The objective of this paper is to contrast the use of a longitudinal incision in surgical decompression of De Quervain disease with a transverse incision. The advantages are ease in recognition of compartment variations and superficial branches of radial nerve and prevention of palmar tendon subluxation by permitting a more dorsal release of the compartment sheath. Since 2002, we have used a longitudinal skin incision instead of the classic transverse incision to release the first dorsal compartment.

  8. Longitudinal dispersion modeling in small streams

    NASA Astrophysics Data System (ADS)

    Pekarova, Pavla; Pekar, Jan; Miklanek, Pavol

    2014-05-01

    The environmental problems caused by the increasing of pollutant loads discharged into natural water bodies are very complex. For that reason the cognition of transport mechanism and mixing characteristics in natural streams is very important. The mathematical and numerical models have become very useful tools for solving the water management problems. The mathematical simulations based on numerical models of pollution mixing in streams can be used (for example) for prediction of spreading of accidental contaminant waves in rivers. The paper deals with the estimation of the longitudinal dispersion coefficients and with the numerical simulation of transport and transformation of accidental pollution in the small natural streams. There are different ways of solving problems of pollution spreading in open channels, in natural rivers. One of them is the hydrodynamic approach, which endeavours to understand and quantify the spreading phenomenon in a stream. The hydrodynamic models are based on advection-diffusion equation and the majority of them are one-dimensional models. Their disadvantage is inability to simulate the spread of pollution until complete dispersion of pollutant across the stream section is finished. Two-dimensional mixing models do not suffer from these limitations. On the other hand, the one-dimensional models are simpler than two-dimensional ones, they need not so much input data and they are often swifter. Three-dimensional models under conditions of natural streams are applicable with difficulties (or inapplicable) for their complexity and demands on accuracy and amount of input data. As there was mentioned above the two-dimensional models can be used also until complete dispersion of pollutant across the stream section is not finished, so we decided to apply the two-dimensional model SIRENIE. Experimental microbasin Rybarik is the part of the experimental Mostenik brook basin of IH SAS Bratislava. It was established as a Field Hydrological

  9. Traveltime and longitudinal dispersion in Illinois streams

    USGS Publications Warehouse

    Graf, Julia B.

    1986-01-01

    Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams made from 1975 to 1982 provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from injection of a given quantity of solute, and passage time of solute past a given point on a stream. These four variables can be estimated graphically for each stream from distance of travel and either discharge at the downstream end of the reach or flow-duration frequency. From equations developed from field measurements, the traveltime and dispersion characteristics also can be estimated for other unregulated streams in Illinois that have drainage areas less than about 1,500 square miles. For unmeasured streams, traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach and to distance of travel. For both measured and unmeasured streams, peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, can be estimated from an equation developed from measured values. The equation relates average reach velocity to discharge at the downstream end of the reach. Average reach velocities computed for 9 of the 10 streams from available equations that are based on hydraulic-geometry relations are high relative to measured values. The estimating equation developed from measured velocities provides estimates of average reach velocity that are closer to measured velocities than are those computed using equations developed from hydraulic-geometry relations.

  10. Longitudinal Association of Dementia and Depression

    PubMed Central

    Snowden, Mark B.; Atkins, David C.; Steinman, Lesley E.; Bell, Janice F.; Bryant, Lucinda L.; Copeland, Catherine; Fitzpatrick, Annette L.

    2015-01-01

    Objectives Depression is an important precursor to dementia, but less is known about the role dementia plays in altering the course of depression. We examined whether depression prevalence, incidence, and severity are higher in those with dementia versus those with mild cognitive impairment (MCI), or normal cognition. Design Prospective cohort study using the longitudinal Uniform Data Set of the National Alzheimer's Coordinating Center (2005–2013). Setting 34 Alzheimer Disease research centers. Participants 27,776 subjects with dementia, MCI, or normal cognition. Measurements Depression status was determined by a clinical diagnosis of depression within the prior 2 years and by a Geriatric Depression Scale-Short Form score >5. Results Rates of depression were significantly higher in subjects with MCI and dementia compared with those with normal cognition at index visit. Controlling for demographics and common chronic conditions, logistic regression analysis revealed elevated depression in those with MCI (OR: 2.40 [95% CI: 2.25, 2.56]) or dementia (OR: 2.64 [95% CI: 2.43, 2.86]) relative to those with normal cognition. In the subjects without depression at the index visit (N = 18,842), those with MCI and dementia had higher probabilities of depression diagnosis 2 years post index visit than those with normal cognition: MCI = 21.7%, dementia 24.7%, normal cognition = 10.5%. Conclusion MCI and dementia were associated with significantly higher rates of depression in concurrent as well as prospective analyses. These findings suggest that efforts to effectively engage and treat older adults with dementia will need also to address co-occurring depression. PMID:25441056

  11. Longitudinal Association of Dementia and Depression.

    PubMed

    Snowden, Mark B; Atkins, David C; Steinman, Lesley E; Bell, Janice F; Bryant, Lucinda L; Copeland, Catherine; Fitzpatrick, Annette L

    2015-09-01

    Depression is an important precursor to dementia, but less is known about the role dementia plays in altering the course of depression. We examined whether depression prevalence, incidence, and severity are higher in those with dementia versus those with mild cognitive impairment (MCI), or normal cognition. Prospective cohort study using the longitudinal Uniform Data Set of the National Alzheimer's Coordinating Center (2005-2013). 34 Alzheimer Disease research centers. 27,776 subjects with dementia, MCI, or normal cognition. Depression status was determined by a clinical diagnosis of depression within the prior 2 years and by a Geriatric Depression Scale-Short Form score >5. Rates of depression were significantly higher in subjects with MCI and dementia compared with those with normal cognition at index visit. Controlling for demographics and common chronic conditions, logistic regression analysis revealed elevated depression in those with MCI (OR: 2.40 [95% CI: 2.25, 2.56]) or dementia (OR: 2.64 [95% CI: 2.43, 2.86]) relative to those with normal cognition. In the subjects without depression at the index visit (N = 18,842), those with MCI and dementia had higher probabilities of depression diagnosis 2 years post index visit than those with normal cognition: MCI = 21.7%, dementia = 24.7%, normal cognition = 10.5%. MCI and dementia were associated with significantly higher rates of depression in concurrent as well as prospective analyses. These findings suggest that efforts to effectively engage and treat older adults with dementia will need also to address co-occurring depression. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

  12. Longitudinal associations between reading and mathematics achievement.

    PubMed

    Grimm, Kevin J

    2008-01-01

    The association between early reading skills and changes in mathematics was examined in a large, low-income sample to determine whether students who have a greater level of reading skills in early elementary school exhibit more rapid gains in tests of mathematics. The longitudinal associations between third grade reading comprehension and changes in three components of mathematics achievement (Problem Solving and Data Interpretation, Mathematical Concepts and Estimation, Mathematical Computation) from third through eighth grade were examined. Latent growth models were fit to the repeated assessments of each mathematics component and the students' third grade reading and global mathematics scores were included as predictors of the intercept and slope. Gender, poverty status, and ethnicity were included in the models as control variables. The results showed males and African-American students tended to have shallower rates of change than females and non-African-American/non-Hispanic students. In terms of the effect of reading on changes in mathematics, third grade reading comprehension was found to be a positive significant predictor of change for each component of mathematics, suggesting students with a greater level of reading achievement in early elementary school change more rapidly in mathematics skills controlling for prior mathematics skills and student characteristics. The largest effects were shown for the Problem Solving and Data Interpretation test, a test focused on the applications of mathematics knowledge, and the Mathematical Concepts and Estimation test. Negligible effects were found for changes in Mathematical Computation. Thus, early reading comprehension was shown to be related to a conceptual understanding of mathematics and the application of mathematics knowledge. These findings lend support for the notion that early reading skills are important for success in mathematics.

  13. Longitudinal Diffusion Tensor Imaging in Frontotemporal Dementia

    PubMed Central

    Mahoney, Colin J; Simpson, Ivor J A; Nicholas, Jennifer M; Fletcher, Phillip D; Downey, Laura E; Golden, Hannah L; Clark, Camilla N; Schmitz, Nicole; Rohrer, Jonathan D; Schott, Jonathan M; Zhang, Hui; Ourselin, Sebastian; Warren, Jason D; Fox, Nick C

    2015-01-01

    Objective Novel biomarkers for monitoring progression in neurodegenerative conditions are needed. Measurement of microstructural changes in white matter (WM) using diffusion tensor imaging (DTI) may be a useful outcome measure. Here we report trajectories of WM change using serial DTI in a cohort with behavioral variant frontotemporal dementia (bvFTD). Methods Twenty-three patients with bvFTD (12 having genetic mutations), and 18 age-matched control participants were assessed using DTI and neuropsychological batteries at baseline and ∼1.3 years later. Baseline and follow-up DTI scans were registered using a groupwise approach. Annualized rates of change for DTI metrics, neuropsychological measures, and whole brain volume were calculated. DTI metric performances were compared, and sample sizes for potential clinical trials were calculated. Results In the bvFTD group as a whole, rates of change in fractional anisotropy (FA) and mean diffusivity (MD) within the right paracallosal cingulum were greatest (FA: −6.8%/yr, p < 0.001; MD: 2.9%/yr, p = 0.01). MAPT carriers had the greatest change within left uncinate fasciculus (FA: −7.9%/yr, p < 0.001; MD: 10.9%/yr, p < 0.001); sporadic bvFTD and C9ORF72 carriers had the greatest change within right paracallosal cingulum (sporadic bvFTD, FA: −6.7%/yr, p < 0.001; MD: 3.8%/yr, p = 0.001; C9ORF72, FA: −6.8%/yr, p = 0.004). Sample size estimates using FA change were substantially lower than neuropsychological or whole brain measures of change. Interpretation Serial DTI scans may be useful for measuring disease progression in bvFTD, with particular trajectories of WM damage emerging. Sample size calculations suggest that longitudinal DTI may be a useful biomarker in future clinical trials. PMID:25363208

  14. Longitudinal respiratory studies in older people

    PubMed Central

    Milne, J S

    1978-01-01

    Milne, J S (1978).Thorax, 33, 547-554. Longitudinal respiratory studies in older people. A random sample of older people in Edinburgh (215 men, 272 women aged 62-90 years) was examined with the MRC questionnaire on respiratory symptoms. The FEV1 and FVC were recorded. Spirograms were repeated after one and five years and the questions after five years, the sample by then having been reduced to 133 men and 148 women. After five years 7% of the surviving men and women had developed persistent cough and phlegm. This syndrome had disappeared in 12% of men and 2% of women. Dyspnoea had increased beyond grade 2 in 13% of men and 7% of women and had lessened only in 6% of women. One-quarter of male and one-seventh of female cigarette smokers had given up smoking, mostly in the first year. Nearly all who stopped were symptomless before and after. In those men who stopped smoking before the study began symptom prevalence was similar to that in those who continued smoking. Mean values of FEV1 and FVC declined as age increased, the decline being greater in FVC with resulting rise in FEV1%. Five-year differences in FEV1 and FVC were symmetrically distributed with mean differences increasing with age. Mean differences in FEV1 were 280-350 ml in men and 150-230 ml in women. Prediction equations from the first examinations remained usable for clinical work. Mean values of FEV1 and FVC at the first examination were smaller in those who died compared with survivors, whether symptoms were present or not. The prevalence of symptoms was greater in those who died. PMID:725823

  15. Longitudinal changes in white matter microstructure after heavy cannabis use

    PubMed Central

    Becker, Mary P.; Collins, Paul F.; Lim, Kelvin O.; Muetzel, R.L.; Luciana, M.

    2015-01-01

    Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment. PMID:26602958

  16. Longitudinal changes in white matter microstructure after heavy cannabis use.

    PubMed

    Becker, Mary P; Collins, Paul F; Lim, Kelvin O; Muetzel, R L; Luciana, M

    2015-12-01

    Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment.

  17. 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.

  18. Longitudinal fluctuations in the Berezinskii-Kosterlitz-Thouless phase

    NASA Astrophysics Data System (ADS)

    Jakubczyk, Pawel; Metzner, Walter

    2017-02-01

    We analyze the interplay of longitudinal and transverse thermal fluctuations in a U(1 ) symmetric two-dimensional ϕ4 theory. Toward this end, we derive coupled renormalization-group equations for both types of fluctuations obtained from a linear (Cartesian) decomposition of the order-parameter field. Discarding the longitudinal fluctuations, the expected Berezinskii-Kosterlitz-Thouless phase characterized by a finite stiffness and an algebraic decay of order-parameter correlations is recovered. Renormalized by transverse fluctuations, the longitudinal mass scales to zero so that longitudinal fluctuations become increasingly important for small momenta. Within our expansion of the effective action, they generate a logarithmic decrease of the stiffness, in agreement with previous functional renormalization-group calculations. The logarithmic terms imply a deviation from the vanishing β function for the stiffness in the nonlinear σ model describing the phase fluctuations at three-loop order. To gain further insight, we also compute the flow of the parameters characterizing longitudinal and transverse fluctuations from a density-phase representation of the order-parameter field, with a cutoff on phase fluctuations. The power-law flow of the longitudinal mass and other quantities is thereby confirmed, but the stiffness remains finite in this approach. We conclude that the marginal flow of the stiffness obtained in the Cartesian representation is an artifact of the truncated expansion of momentum dependences.

  19. Night shifts in emergency medicine: the american board of emergency medicine longitudinal study of emergency physicians.

    PubMed

    Smith-Coggins, Rebecca; Broderick, Kerryann B; Marco, Catherine A

    2014-09-01

    Night shift work is an integral component of the practice of emergency medicine (EM). Previous studies have demonstrated the challenges of night shift work to health and well being among health care providers. This study was undertaken to describe the self-reported experience of emergency physicians regarding night shift work with respect to quality of life and career satisfaction. The 2008 American Board of Emergency Medicine (ABEM) Longitudinal Study of Emergency Physicians (LSEP) was administered by mail to 1003 ABEM diplomates. Among 819 participants in the 2008 LSEP Physician Survey, most participants responded that night shift work negatively influenced job satisfaction with a moderate or major negative influence (58%; n = 467/800). Forty-three percent of participants indicated that night shifts had caused them to think about leaving EM (n = 344/809). Most participants responded that working night shifts has had mild negative effects (51%; n = 407/800) or major negative effects (9%; n = 68) on their health. Respondents were asked to describe how working night shifts has affected their health. Common themes included fatigue (36%), poor quality of sleep (35%), mood decrement/irritability (29%), and health maintenance challenges (19%). Among participants in the 2008 LSEP Retired Physician Survey, night shifts were a factor in the decision to retire for 56% of participants. Emergency physicians report negative impacts of night shift work, including fatigue, poor quality of sleep, mood decrement, irritability, and health challenges. Night shifts have a negative influence on job satisfaction and can be a factor in the decision to retire. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. DOE/EM Criticality Safety Needs Assessment

    SciTech Connect

    Westfall, Robert Michael; Hopper, Calvin Mitchell

    2011-02-01

    The issue of nuclear criticality safety (NCS) in Department of Energy Environmental Management (DOE/EM) fissionable material operations presents challenges because of the large quantities of material present in the facilities and equipment that are committed to storage and/or material conditioning and dispositioning processes. Given the uncertainty associated with the material and conditions for many DOE/EM fissionable material operations, ensuring safety while maintaining operational efficiency requires the application of the most-effective criticality safety practices. In turn, more-efficient implementation of these practices can be achieved if the best NCS technologies are utilized. In 2002, DOE/EM-1 commissioned a survey of criticality safety technical needs at the major EM sites. These needs were documented in the report Analysis of Nuclear Criticality Safety Technology Supporting the Environmental Management Program, issued May 2002. Subsequent to this study, EM safety management personnel made a commitment to applying the best and latest criticality safety technology, as described by the DOE Nuclear Criticality Safety Program (NCSP). Over the past 7 years, this commitment has enabled the transfer of several new technologies to EM operations. In 2008, it was decided to broaden the basis of the EM NCS needs assessment to include not only current needs for technologies but also NCS operational areas with potential for improvements in controls, analysis, and regulations. A series of NCS workshops has been conducted over the past years, and needs have been identified and addressed by EM staff and contractor personnel. These workshops were organized and conducted by the EM Criticality Safety Program Manager with administrative and technical support by staff at Oak Ridge National Laboratory (ORNL). This report records the progress made in identifying the needs, determining the approaches for addressing these needs, and assimilating new NCS technologies into EM

  1. Hadron calorimeter performance with a PbWO4 EM compartment

    SciTech Connect

    Green, D.

    1996-01-01

    The CMS detector[1] at the LHC has chosen PbWO4 in order to achieve the superior photon energy resolution which is crucial in searching for the 2 photon decay of low mass Higgs bosons. The hadronic compartment is thought to be Cu absorber, since one is immersed in a 4 T magnetic field, read out by scintillator tiles coupled to wavelength shifter (WLS) fibers. The combined performance of this calorimeter is of interest in the study of jets and missing transverse energy (neutrino, SUSY signatures). For this reason, a test was made of the electromagnetic (EM) compartment combined with a reasonable approximation to the baseline HCAL ``barrel`` calorimeter. Data was taken in the H4 CERN beamline. The EM compartment was a 7 {times} 7 square array of PbWO4 crystals, which for the purposes of this study are considered as a single readout in depth (or ``compartment``) [2]. The HCAL module consisted of large scintillator plates with 24 individual longitudinal readout channels. The EM compartment was followed by 10 Cu plates each 3 cm thick, followed by 9 Cu plates each 6 cm thick. This set of absorber plates represented the HCAL compartments inside the coil. The coil itself [1] was approximated as Al and Fe plates, of a total thickness of about 1.4 absorption lengths. The coil mockup was sampled and then followed by 4 plates of 8 cm thick Cu, each with an individual readout which represented a test of the ``Tailcatcher`` concept.

  2. Longitudinal Change of Biomarkers in Cognitive Decline

    PubMed Central

    Lo, Raymond Y.; Hubbard, Alan E.; Shaw, Leslie M.; Trojanowski, John Q.; Petersen, Ronald C.; Aisen, Paul S.; Weiner, Michael W.; Jagust, William J.

    2017-01-01

    Objective To delineate the trajectories of Aβ42 level in cerebrospinal fluid (CSF), fludeoxyglucose F18 (FDG) uptake using positron emission tomography, and hippocampal volume using magnetic resonance imaging and their relative associations with cognitive change at different stages in aging and Alzheimer disease (AD). Design Cohort study. Setting The 59 study sites for the Alzheimer’s Disease Neuroimaging Initiative. Participants A total of 819 participants 55 to 90 years of age with normal cognition, mild cognitive impairment, and AD who were followed up during the period from 2005 to 2007. Main Outcome Measures Rates of change in level of Aβ42 in CSF, FDG uptake, hippocampal volume, and the Alzheimer Disease’s Assessment Scale–cognitive subscale score during up to 36 months of follow-up by diagnostic group as well as prediction of cognitive change by each biomarker. Results Reductions in the level of Aβ42 in CSF were numerically greater in participants with normal cognition than in participants with mild cognitive impairment or AD; whereas both glucose metabolic decline and hippocampal atrophy were significantly slower in participants with normal cognition than in participants with mild cognitive impairment or AD. Positive APOE4 status accelerated hippocampal atrophic changes in participants with mild cognitive impairment or AD, but did not modify rates of change in level of Aβ42 in CSF or FDG uptake. The Alzheimer Disease’s Assessment Scale–cognitive subscale scores were related only to the baseline level of Aβ42 in CSF and the baseline FDG uptake in participants with normal cognition, which were about equally associated with change in FDG uptake and hippocampal volume in participants with mild cognitive impairment and best modeled by change in FDG uptake in participants with AD. Conclusion Trajectories of Aβ42 level in CSF, FDG uptake, and hippocampal volume vary across different cognitive stages. The longitudinal patterns support a hypothetical

  3. Longitudinal nonlinear wave propagation through soft tissue.

    PubMed

    Valdez, M; Balachandran, B

    2013-04-01

    In this paper, wave propagation through soft tissue is investigated. A primary aim of this investigation is to gain a fundamental understanding of the influence of soft tissue nonlinear material properties on the propagation characteristics of stress waves generated by transient loadings. Here, for computational modeling purposes, the soft tissue is modeled as a nonlinear visco-hyperelastic material, the geometry is assumed to be one-dimensional rod geometry, and uniaxial propagation of longitudinal waves is considered. By using the linearized model, a basic understanding of the characteristics of wave propagation is developed through the dispersion relation and in terms of the propagation speed and attenuation. In addition, it is illustrated as to how the linear system can be used to predict brain tissue material parameters through the use of available experimental ultrasonic attenuation curves. Furthermore, frequency thresholds for wave propagation along internal structures, such as axons in the white matter of the brain, are obtained through the linear analysis. With the nonlinear material model, the authors analyze cases in which one of the ends of the rods is fixed and the other end is subjected to a loading. Two variants of the nonlinear model are analyzed and the associated predictions are compared with the predictions of the corresponding linear model. The numerical results illustrate that one of the imprints of the nonlinearity on the wave propagation phenomenon is the steepening of the wave front, leading to jump-like variations in the stress wave profiles. This phenomenon is a consequence of the dependence of the local wave speed on the local deformation of the material. As per the predictions of the nonlinear material model, compressive waves in the structure travel faster than tensile waves. Furthermore, it is found that wave pulses with large amplitudes and small elapsed times are attenuated over shorter spans. This feature is due to the elevated

  4. Longitudinal Course of Bipolar I Disorder

    PubMed Central

    Solomon, David A.; Leon, Andrew C.; Coryell, William H.; Endicott, Jean; Li, Chunshan; Fiedorowicz, Jess G.; Boyken, Lara; Keller, Martin B.

    2013-01-01

    Context The phenomenology of bipolar I disorder affects treatment and prognosis. Objective To describe the duration of bipolar I mood episodes and factors associated with recovery from these episodes. Design Subjects with Research Diagnostic Criteria bipolar I disorder were prospectively followed up for as long as 25 years. The probability of recovery over time from multiple successive mood episodes was examined with survival analytic techniques, including a mixed-effects grouped-time survival model. Setting Five US academic medical centers. Participants Two hundred nineteen subjects with bipolar I disorder. Main Outcome Measures Level of psychopathology was assessed with the Longitudinal Interval Follow-up Evaluation every 6 months for the first 5 years of follow-up and annually thereafter. Results The median duration of bipolar I mood episodes was 13 weeks. More than 75% of the subjects recovered from their mood episodes within 1 year of onset. The probability of recovery was significantly less for an episode with severe onset (psychosis or severe psychosocial impairment in week 1 of the episode) (hazard ratio [HR]=0.746; 95% confidence interval [CI], 0.578–0.963; P=.02) and for subjects with greater cumulative morbidity (total number of years spent ill with any mood episode) (HR=0.917; 95% CI, 0.886–0.948; P<.001). Compared with the probability of recovery from a major depressive episode, there was a significantly greater probability of recovery from an episode of mania (HR=1.713; 95% CI, 1.373–2.137; P<.001), hypomania (HR=4.502; 95% CI, 3.466–5.849; P<.001), or minor depression (HR = 2.027; 95% CI, 1.622–2.534; P<.001) and, conversely, a significantly reduced probability of recovery from a cycling episode (switching from one pole to the other without an intervening period of recovery) (HR=0.438; 95% CI, 0.351–0.548; P<.001). Conclusions The median duration of bipolar I mood episodes was 13 weeks, and the probability of recovery was significantly

  5. EMS provider determinations of necessity for transport and reimbursement for EMS response, medical care, and transport: combined resource document for the National Association of EMS Physicians position statements.

    PubMed

    Millin, Michael G; Brown, Lawrence H; Schwartz, Brian

    2011-01-01

    With increasing demands for emergency medical services (EMS), many EMS jurisdictions are utilizing EMS provider-initiated nontransport policies as a method to offload potentially nonemergent patients from the EMS system. EMS provider determination of medical necessity, resulting in nontransport of patients, has the potential to avert unnecessary emergency department visits. However, EMS systems that utilize these policies must have additional education for the providers, a quality improvement process, and active physician oversight. In addition, EMS provider determination of nontransport for a specific situation should be supported by evidence in the peer-reviewed literature that the practice is safe. Further, EMS systems that do not utilize these programs should not be financially penalized. Payment for EMS services should be based on the prudent layperson standard. EMS systems that do utilize nontransport policies should be appropriately reimbursed, as this represents potential cost savings to the health care system.

  6. School Budget Hold'em Facilitator's Guide

    ERIC Educational Resources Information Center

    Education Resource Strategies, 2012

    2012-01-01

    "School Budget Hold'em" is a game designed to help school districts rethink their budgeting process. It evolved out of Education Resource Strategies' (ERS) experience working with large urban districts around the country. "School Budget Hold'em" offers a completely new approach--one that can turn the budgeting process into a long-term visioning…

  7. Longitudinal SNP-set association analysis of quantitative phenotypes.

    PubMed

    Wang, Zhong; Xu, Ke; Zhang, Xinyu; Wu, Xiaowei; Wang, Zuoheng

    2017-01-01

    Many genetic epidemiological studies collect repeated measurements over time. This design not only provides a more accurate assessment of disease condition, but allows us to explore the genetic influence on disease development and progression. Thus, it is of great interest to study the longitudinal contribution of genes to disease susceptibility. Most association testing methods for longitudinal phenotypes are developed for single variant, and may have limited power to detect association, especially for variants with low minor allele frequency. We propose Longitudinal SNP-set/sequence kernel association test (LSKAT), a robust, mixed-effects method for association testing of rare and common variants with longitudinal quantitative phenotypes. LSKAT uses several random effects to account for the within-subject correlation in longitudinal data, and allows for adjustment for both static and time-varying covariates. We also present a longitudinal trait burden test (LBT), where we test association between the trait and the burden score in linear mixed models. In simulation studies, we demonstrate that LBT achieves high power when variants are almost all deleterious or all protective, while LSKAT performs well in a wide range of genetic models. By making full use of trait values from repeated measures, LSKAT is more powerful than several tests applied to a single measurement or average over all time points. Moreover, LSKAT is robust to misspecification of the covariance structure. We apply the LSKAT and LBT methods to detect association with longitudinally measured body mass index in the Framingham Heart Study, where we are able to replicate association with a circadian gene NR1D2. © 2016 WILEY PERIODICALS, INC.

  8. EM Cep: The Be Star

    NASA Astrophysics Data System (ADS)

    Kochiashvili, N.; Kochiashvili, I.; Natsvlishvili, R.; Vardosanidze, M.; Beradze, S.

    2017-07-01

    On the basis of UBVR photometric data, obtained in the Abastumani Observatory during 1991-1999, very interesting and unusual flare of EM Cep has been revealed. Duration of the flare was over two hours. We estimated the percentage of brightness increase during the flare and brightness decrease of the corresponding anti- flare and the minimum amount of the lost mass during this event. We have solved the light curves of the star using the Wilson-Devinney code. But the resulting fraction of calculated brightness of the companion star was not in accordance with spectral data. Then we decided to check the idea of a pulsating single star using new spectral data. Together with our Buyrakan colleagues we obtained and analyzed spectra of the star. We could not find spectral lines of a companion star or any traces of the radial velocities using this data. Hence, we concluded that we need the higher resolution spectra for final resolution of the matter. On the basis of the latest spectral data of Bulgarian astronomers they concluded that EM Cep is a single star. This makes it possible to suggest, that the question of stellar pulsation could be solved using additional photometric observations.

  9. The EM algorithm in medical imaging.

    PubMed

    Kay, J

    1997-03-01

    This article outlines the statistical developments that have taken place in the use of the EM algorithm in emission and transmission tomography during the past decade or so. We discuss the statistical aspects of the modelling of the projection data for both the emission and transmission cases and define the relevant probability models. This leads to the use of the method of maximum likelihood as a means of estimating the relevant unknown parameters within a given region of a patient's body and to the use of the EM algorithm to compute the reconstruction. Various different types of EM algorithm are discussed, including the SAGE algorithms of Fessler and Hero. The limitations of the EM algorithm, per se, are covered and the need for regularization is stressed. A number of different methods for penalizing the likelihood are described and a number of algorithms for the computation of the penalized EM reconstruction are discussed.

  10. Side mounted EMS for aluminium scrap melters

    SciTech Connect

    Eidem, M.; Tallbaeck, G.; Hanley, P.J.

    1996-10-01

    Normally the electromagnetic stirrer (EMS) is placed below the furnace. However it has recently been found that the EMS can also be placed at the side of the furnace, still giving good stirring. This makes it possible to install EMS on most existing furnaces. The side-mounted EMS is compared with the standard bottom-mounted stirrer with respect to installation, melting time and flow pattern in the melt. The major conclusion is that a side-mounted EMS is practical and will give about as good a performance as the bottom-mounted. Melting time estimates are based upon 3-D fluid flow and heat transfer predictions in combination with a simplified scrap melting theory. Predicted melting times are in fair agreement with operational data for mechanically stirred and electromagnetically bottom stirred furnaces.

  11. Mixed-effects state-space models for analysis of longitudinal dynamic systems.

    PubMed

    Liu, Dacheng; Lu, Tao; Niu, Xu-Feng; Wu, Hulin

    2011-06-01

    The rapid development of new biotechnologies allows us to deeply understand biomedical dynamic systems in more detail and at a cellular level. Many of the subject-specific biomedical systems can be described by a set of differential or difference equations that are similar to engineering dynamic systems. In this article, motivated by HIV dynamic studies, we propose a class of mixed-effects state-space models based on the longitudinal feature of dynamic systems. State-space models with mixed-effects components are very flexible in modeling the serial correlation of within-subject observations and between-subject variations. The Bayesian approach and the maximum likelihood method for standard mixed-effects models and state-space models are modified and investigated for estimating unknown parameters in the proposed models. In the Bayesian approach, full conditional distributions are derived and the Gibbs sampler is constructed to explore the posterior distributions. For the maximum likelihood method, we develop a Monte Carlo EM algorithm with a Gibbs sampler step to approximate the conditional expectations in the E-step. Simulation studies are conducted to compare the two proposed methods. We apply the mixed-effects state-space model to a data set from an AIDS clinical trial to illustrate the proposed methodologies. The proposed models and methods may also have potential applications in other biomedical system analyses such as tumor dynamics in cancer research and genetic regulatory network modeling.

  12. A comparative investigation of methods for longitudinal data with limits of detection through a case study.

    PubMed

    Fu, P; Hughes, J; Zeng, G; Hanook, S; Orem, J; Mwanda, O W; Remick, S C

    2016-02-01

    The statistical analysis of continuous longitudinal data may be complicated since quantitative levels of bioassay cannot always be determined. Values beyond the limits of detection (LOD) in the assays may not be observed and thus censored, rendering complexity to the analysis of such data. This article examines how both left-censoring and right censoring of HIV-1 plasma RNA measurements, collected for the study on AIDS-related Non-Hodgkin's lymphoma (AR-NHL) in East Africa, affects the quantification of viral load and explores the natural history of viral load measurements over time in AR-NHL patients receiving anticancer chemotherapy. Data analyses using Monte Carlo EM algorithm (MCEM) are compared to analyses where the LOD or LOD/2 (left censoring) value is substituted for the censored observations, and also to other methods such as multiple imputation, and maximum likelihood estimation for censored data (generalized Tobit regression). Simulations are used to explore the sensitivity of the results to changes in the model parameters. In conclusion, the antiretroviral treatment was associated with a significant decrease in viral load after controlling the effects of other covariates. A simulation study with finite sample size shows MCEM is the least biased method and the estimates are least sensitive to the censoring mechanism. © The Author(s) 2012.

  13. RF impedance studies of a beam chamber and longitudinally slot-coupled vacuum pumping antechamber

    SciTech Connect

    Kustom, R.L.; Nicholls, G.L.; Kramer, S.L.; Khoe, T.K.; Cook, J.M.

    1987-01-01

    The storage ring vacuum chamber of the proposed 7-GeV synchrotron light source at Argonne National Laboratory is planned to have a semi-elliptical beam chamber, with a longitudinal slot coupled to an antechamber containing NEG pumping strips. Concern over the RF impedance of this complex chamber has stimulated the need to understand the limitations it will have on the beam intensity, the RF acceleration system and on the beam lifetime. Calculations using numerical EM field programs have estimated the waveguide modes of this chamber and the impedance and loss parameter for the expected 1 to 2 cm beam bunch length. The loss parameter is shown to differ little from an elliptical beam chamber without the slot and antechamber. An experimental program has begun to verify the estimates of the impedance for these complex vacuum chamber components using laboratory methods. Preliminary results are presented for the measured loss parameter for a short length of beam vacuum chamber and for other components. These results are compared with their calculated values.

  14. Beam Loss and Longitudinal Emittance Growth in SIS

    NASA Astrophysics Data System (ADS)

    Kirk, M.; Hofmann, I.; Boine-Frankenheim, O.; Spiller, P.; Hülsmann, P.; Franchetti, G.; Damerau, H.; König, H. Günter; Klingbeil, H.; Kumm, M.; Moritz, P.; Schütt, P.; Redelbach, A.

    2005-06-01

    Beam losses of several percent occur regularly in SIS. The onset occurs during the RF capture of the beam. Previous studies have revealed that the losses can come from the RF bucket at the start of acceleration being over filled due to the longitudinal bucket acceptance being too small, or due to the mismatch between the mean energy from the UNILAC and synchronous energy of the SIS. The beam losses as measured by a DC beam transformer however show in addition to the sharp initial drop, for the above reasons, a much slower decay in the beam intensity. The speculated cause comes from the incoherent transverse tune shift of the bunched beam, which forces particles into transverse resonant conditions. The longitudinal emittance growth is also another important issue for SIS. Past measurements from Schottky-noise pick-ups have shown a factor of 3-5 increase in the longitudinal emittance depending on the extraction energy; a large factor when compared against expectations from theory. These factors were calculated from the ratio between the normalized relative momentum spread of the DC beam before RF capture and after debunching. In this present work, tomographical techniques have been used to reconstruct the phasespace from a series of bunch profile measurements from a Beam Position Monitor (BPM). Therefore one can find the rate of growth in the longitudinal emittance from a series of high resolution BPM measurements along the RF ramp. Furthermore the initial phasespace density matrix from these reconstructions has been used to generate the initial population of macroparticles for the ESME longitudinal dynamics Particle-In-Cell code, thereby enabling a comparison between the longitudinal emittance growth of the beam under ideal conditions and that of the experiment. The longitudinal emittance growth (rms) during the acceleration (˜540ms) was approximately 20%, and that during the RF capture was estimated to have an upper limit of about 40%. Later measurements have also

  15. A multiple imputation strategy for incomplete longitudinal data.

    PubMed

    Landrum, M B; Becker, M P

    Longitudinal studies are commonly used to study processes of change. Because data are collected over time, missing data are pervasive in longitudinal studies, and complete ascertainment of all variables is rare. In this paper a new imputation strategy for completing longitudinal data sets is proposed. The proposed methodology makes use of shrinkage estimators for pooling information across geographic entities, and of model averaging for pooling predictions across different statistical models. Bayes factors are used to compute weights (probabilities) for a set of models considered to be reasonable for at least some of the units for which imputations must be produced, imputations are produced by draws from the predictive distributions of the missing data, and multiple imputations are used to better reflect selected sources of uncertainty in the imputation process. The imputation strategy is developed within the context of an application to completing incomplete longitudinal variables in the so-called Area Resource File. The proposed procedure is compared with several other imputation procedures in terms of inferences derived with the imputations, and the proposed methodology is demonstrated to provide valid estimates of model parameters when the completed data are analysed. Extensions to other missing data problems in longitudinal studies are straightforward so long as the missing data mechanism can be assumed to be ignorable.

  16. Theoretical study of transverse-longitudinal emittance coupling

    SciTech Connect

    Qin, H; Davidson, R C; Chung, M; Barnard, J J; Wang, T F

    2011-04-14

    The effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions is investigated using the generalized Courant-Snyder theory for coupled lattices. Recently, the concept and technique of transverse-longitudinal emittance coupling have been proposed for applications in the Linac Coherent Light Source and other free-electron lasers to reduce the transverse emittance of the electron beam. Such techniques can also be applied to the driver beams for the heavy ion fusion and beam-driven high energy density physics, where the transverse emittance budget is typically tighter than the longitudinal emittance. The proposed methods consist of one or several coupling components which completely swap the emittances of one of the transverse directions and the longitudinal direction at the exit of the coupling components. The complete emittance exchange is realized in one pass through the coupling components. In the present study, we investigate the effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions. A weak coupling component is introduced at every focusing lattice, and we would like to determine if such a lattice can realize the function of emittance exchange.

  17. Nursing Diagnoses of hospitalized patients with heart failure: a longitudinal study.

    PubMed

    Pereira, Juliana de Melo Vellozo; Flores, Paula Vanessa Peclat; Figueiredo, Lyvia da Silva; Arruda, Cristina Silva; Cassiano, Keila Mara; Vieira, Gláucia Cristina Andrade; Guerra, Thais de Rezende Bessa; Silva, Vanessa Alves da; Cavalcanti, Ana Carla Dantas

    2016-01-01

    Identifying Nursing Diagnoses of fatigue, activity intolerance and decreased cardiac output in hospitalized patients with heart failure and verifying the association between the defining characteristics and the Nursing Diagnoses. A longitudinal and prospective study that followed hospitalized patients with heart failure for three weeks. The data collected through interviews and physical examinations were sent to expert nurses for diagnostic inference. Descriptive and inferential statistical analyses were carried out. Of the 72 patients, 68.0% were male and presented the nursing diagnosis of decreased cardiac output (62.5%) in the first week, reducing to 52.8% and 38% in the second and third weeks, respectively. Fatigue only appeared in one patient. Activity intolerance was the diagnosis that had the greatest discrepancy among the experts. Decreased cardiac output was associated to the defining characteristics: dyspnea, edema, jugular venous distension and reduced ejection fraction during all three weeks of evaluation. Decreased cardiac output was more prevalent in hospitalized patients with heart failure, and the associated defining characteristics were determining factors for this nursing diagnosis. Identificar os diagnósticos de enfermagem fadiga, intolerância à atividade e débito cardíaco diminuído em pacientes com insuficiência cardíaca hospitalizados e verificar a associação entre as características definidoras e os diagnósticos de enfermagem. Estudo longitudinal e prospectivo que acompanhou pacientes com insuficiência cardíaca hospitalizados por três semanas. Os dados coletados por entrevista e exame físico foram encaminhados a enfermeiros peritos para inferência diagnóstica. Realizou-se análise estatística descritiva e inferencial. Dos 72 pacientes, 68,0% eram do sexo masculino e apresentaram o diagnóstico de enfermagem débito cardíaco diminuído (62,5%) na primeira semana, reduzindo para 52,8% e 38% na segunda e terceira semana

  18. Exploratory analysis of longitudinal trials with staggered intervention times.

    PubMed

    Sousa, Inês; Chetwynd, Amanda G; Diggle, Peter J

    2005-07-01

    Longitudinal trials involving surgical interventions commonly have subject-specific intervention times, due to constraints on the availability of surgeons and operating theatres. Moreover, the intervention often effects a discontinuous change in the mean response. We propose a nonparametric estimator for the mean response profile of longitudinal data with staggered intervention times and a discontinuity at the times of intervention, as an exploratory tool to assist the formulation of a suitable parametric model. We use an adaptation of the standard generalized additive model algorithm for estimation, with smoothing constants chosen by a cross-validation criterion. We illustrate the method using longitudinal data from a trial to assess the effect of lung resection surgery in the treatment of emphysema patients.

  19. Longitudinal beam dynamics for heavy ion fusion using WARPrz

    SciTech Connect

    Callahan, D.A.; Langdon, A.B.; Friedman, A.; Haber, I.

    1993-02-22

    WARPrz is a 2.5 dimensional, cylindrically symmetric, electrostatic, particle-in-cell code. It is part of the WARP family of codes which has been developed to study heavy ion fusion driver issues. WARPrz is being used to study the longitudinal dynamics of heavy ion beams including a longitudinal instability that is driven by the impedance of the LINAC accelerating modules. This instability is of concern because it can enhance longitudinal momentum spread; chromatic abhoration in the lens system restricts the amount of momentum spread allowed in the beam in the final focusing system. The impedance of the modules is modeled by a continuum of resistors and capacitors in parallel in WARPrz. We discuss simulations of this instability including the effect of finite temperature and reflection of perturbations off the beam ends. We also discuss intermittency of axial confining fields (``ears`` fields) as a seed for this instability.

  20. Procedure of measuring the longitudinal emittance of electron beam

    NASA Astrophysics Data System (ADS)

    Vladimirov, I. Yu

    2016-09-01

    The procedure of measuring the longitudinal emittance of electron beam generated by RF gun and reconstruction of its longitudinal phase portrait is proposed. Measuring system consists of vertical deflecting RF cavity, horizontal bending dipole and screen. The beam spot on the screen is used to reconstruct the longitudinal phase portrait. In the proposed procedure an electromagnetic field of the vertical deflecting RF cavity can be approximated by the TM110 mode of pillbox cavity. This approximation allows analytically solve the motion equations of the electron motion in the vertical deflecting RF cavity. The report contains description of the vertical deflecting RF cavity and the dipole, the formulae underlying the procedure and the results of numerical simulation.

  1. Using Administrative Data for Longitudinal Substance Abuse Research

    PubMed Central

    Evans, Elizabeth; Grella, Christine E.; Murphy, Debra A.; Hser, Yih-Ing

    2008-01-01

    The utilization of administrative data in substance abuse research has become more widespread than ever. This selective review synthesizes recent extant research from 31 articles to consider what has been learned from using administrative data to conduct longitudinal substance abuse research in four overlapping areas: (1) service access and utilization, (2) underrepresented populations, (3) treatment outcomes, and (4) cost analysis. Despite several notable limitations, administrative data contribute valuable information, particularly in the investigation of service system interactions and outcomes among substance abusers as they unfold and influence each other over the long term. This critical assessment of the advantages and disadvantages of using existing administrative data within a longitudinal framework should stimulate innovative thinking regarding future applications of administrative data for longitudinal substance abuse research purposes. PMID:18679805

  2. Longitudinal image registration with non-uniform appearance change.

    PubMed

    Csapo, Istvan; Davis, Brad; Shi, Yundi; Sanchez, Mar; Styner, Martin; Niethammer, Marc

    2012-01-01

    Longitudinal imaging studies are frequently used to investigate temporal changes in brain morphology. Image intensity may also change over time, for example when studying brain maturation. However, such intensity changes are not accounted for in image similarity measures for standard image registration methods. Hence, (i) local similarity measures, (ii) methods estimating intensity transformations between images, and (iii) metamorphosis approaches have been developed to either achieve robustness with respect to intensity changes or to simultaneously capture spatial and intensity changes. For these methods, longitudinal intensity changes are not explicitly modeled and images are treated as independent static samples. Here, we propose a model-based image similarity measure for longitudinal image registration in the presence of spatially non-uniform intensity change.

  3. [The problem of repeated measurements. Longitudinal analysis in epidemiology].

    PubMed

    Sáez, M

    2001-01-01

    In longitudinal analyses subjects are repeatedly measured along time. They are mixed designs, characterised for their simultaneous consideration of two or more dimensions of analysis, in which time is one of the dimensions.Longitudinal analyses have important advantages with respect other designs. The most important is that they are more efficient, since they allow to distinguish between-individual and within-individual variation.Longitudinal analyses can be approached marginal and conditionally. Whereas the former allows to draw poblational, or average, inferences, the latter permits to draw individual inferences.The statistical models to use depend on the type of response variable. If the dependent variable is normally distributed one will use linear mixed models. When the response is a count one will use mixed Poisson regressions. Mixed binomial or multinomial logistic regressions should be used when the response would be categorical.

  4. Simulation of the ALS longitudinal multibunch feedback system

    SciTech Connect

    Byrd, J.

    1993-05-01

    Longitudinal coupled bunch growth rates in the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation, indicate the need for damping via a feedback (FB) system. The design of the system is based on the proposed PEP-II longitudinal FB system which uses a digital filter to provide the required phase and amplitude response. We report the results of a detailed computer simulation of the FB system including single particle longitudinal beam dynamics, measured RF cavity fundamental and higher order modes, and response of major FB components such as the power amplifier and kicker. The simulation addresses issues such as required FB power and gain, noise, digital filter effects, and varying initial bunch conditions.

  5. Young's modulus of BF wood material by longitudinal vibration

    NASA Astrophysics Data System (ADS)

    Phadke, Sushil; Darshan Shrivastava, Bhakt; Mishra, Ashutosh; Dagaonkar, N.

    2014-09-01

    All engineered structures are designed and built with consideration of resisting the same fundamental forces of tension, compression, shear, bending and torsion. Structural design is a balance of these internal and external forces. So, it is interesting to calculate the Young's moduli of Borassus Flabellifier BF wood are quite important from the application point of view. The ultrasonic waves are closely related with the elastic and inelastic properties of the materials. In the present study, we measured longitudinal wave ultrasonic velocities in BF wood material by longitudinal vibration method. After measuring ultrasonic velocity in BF wood material, we calculated Young's modulus of Borassus Flabellifier BF wood material. We used ultrasonic interferometer for measuring longitudinal wave ultrasonic velocity in BF wood material made by Mittal Enterprises, New Delhi, India in our laboratory. Borassus Flabellifier BF wood material was collected from Dhar district of Madhya Pradesh, India.

  6. Nonlinear Cascade Strategy for Longitudinal Control of Electric Vehicle.

    PubMed

    El Majdoub, K; Giri, F; Ouadi, H; Chaoui, F Z

    2014-01-01

    The problem of controlling the longitudinal motion of front-wheels electric vehicle (EV) is considered making the focus on the case where a single dc motor is used for both front wheels. Chassis dynamics are modelled applying relevant fundamental laws taking into account the aerodynamic effects and the road slope variation. The longitudinal slip, resulting from tire deformation, is captured through Kiencke's model. Despite its highly nonlinear nature the complete model proves to be utilizable in longitudinal control design. The control objective is to achieve a satisfactory vehicle speed regulation in acceleration/deceleration stages, despite wind speed and other parameters uncertainty. An adaptive controller is developed using the backstepping design technique. The obtained adaptive controller is shown to meet its objectives in presence of the changing aerodynamics efforts and road slope.

  7. Longitudinal research with sexual assault survivors: a methodological review.

    PubMed

    Campbell, Rebecca; Sprague, Heather Brown; Cottrill, Sara; Sullivan, Cris M

    2011-02-01

    Longitudinal research designs are relatively rare in the academic literature on rape and sexual assault despite their tremendous methodological rigor and scientific utility. In the interest of promoting wider use of such methods, we conducted a methodological review of projects that have used prospective longitudinal designs to study the occurrence of sexual victimization throughout the lifespan and/or the process of change during rape recovery (N = 32 projects). Five questions were examined: (a) What were the substantive foci of these longitudinal studies? (b) How were survivors recruited? (c) What participation rates were typical? (d) How long were participants followed over time and with what success rates? and (e) What incentives were used to increase participation? Most studies focused on postassault sequelae and recruited survivors from hospital emergency departments and other first-response help-seeking sites with highly variable participation rates. Retention rates were comparable across studies (approximately 70%).

  8. Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

    PubMed

    Yao, K; Koc, B; Uchino, K

    2001-07-01

    Longitudinal-bending mode ultrasonic motors with a diameter of 3 mm were fabricated using stacked multilayer piezoelectric actuators, which were self-developed from hard lead zirconate titanate (PZT) ceramic. A bending vibration was converted from a longitudinal vibration with a longitudinal-bending coupler. The motors could be bidirectionally operated by changing driving frequency. Their starting and braking torque were analyzed based on the transient velocity response. With a load of moment of inertia 2.5 x 10(-7) kgm2, the motor showed a maximum starting torque of 127.5 microNm. The braking torque proved to be a constant independent on the motor's driving conditions and was roughly equivalent to the maximum starting torque achievable with our micromotors.

  9. Longitudinal evidence for diminished frontal cortex function in aging

    PubMed Central

    Nyberg, Lars; Salami, Alireza; Andersson, Mikael; Eriksson, Johan; Kalpouzos, Grégoria; Kauppi, Karolina; Lind, Johanna; Pudas, Sara; Persson, Jonas; Nilsson, Lars-Göran

    2010-01-01

    Cross-sectional estimates of age-related changes in brain structure and function were compared with 6-y longitudinal estimates. The results indicated increased sensitivity of the longitudinal approach as well as qualitative differences. Critically, the cross-sectional analyses were suggestive of age-related frontal overrecruitment, whereas the longitudinal analyses revealed frontal underrecruitment with advancing age. The cross-sectional observation of overrecruitment reflected a select elderly sample. However, when followed over time, this sample showed reduced frontal recruitment. These findings dispute inferences of true age changes on the basis of age differences, hence challenging some contemporary models of neurocognitive aging, and demonstrate age-related decline in frontal brain volume as well as functional response. PMID:21156826

  10. Longitudinal statistics of plasma bubbles: Possible tropospheric influence

    NASA Astrophysics Data System (ADS)

    Sidorova, L. N.; Filippov, S. V.

    2016-07-01

    The assumption about the possible influence of a tropospheric source on the nature of the longitudinal statistics variation (relative frequency of observation) of plasma bubbles determined by the He+ density in the upper ionosphere altitudes is tested. To do this, the statistics are comparatively analyzed with a number of characteristics of the ionosphere and thermosphere, the longitudinal changes of which can be related to the DE3 tidal wave generated in the troposphere. Evidence of the possible influence of the troposphere on the longitudinal statistics of plasma bubbles has been obtained. Based on qualitative analysis, it was found that the thermospheric winds modulated by the DE3 tidal wave can link these statistics with processes in the troposphere.

  11. EM International, July 1994, Volume 2

    SciTech Connect

    Not Available

    1994-10-01

    The Office of Environmental Management (EM) at the Department of Energy (DOE) is seeking out and leveraging foreign technology, data, and resources in keeping with EM`s mandate to protect public health and the environment through the safe and cost-effective remediation of the Department`s nuclear weapons sites. EM works closely with foreign governments, industry, and universities to obtain innovative environmental technologies, scientific and engineering expertise, and operations experience that will support EM`s objectives. Where appropriate, these international resources are used to manage the more urgent risks at our sites, secure a safe workplace, help build consensus on critical issues, and strengthen our technology development program. Through international agreements EM engages in cooperative exchange of information, technology, and individuals. Currently, we are managing agreements with a dozen countries in Europe, Latin America, and Asia. These agreements focus on environmental restoration, waste management, transportation of radioactive wastes, and decontamination and decommissioning. This publication contains the following articles: in situ remediation integrated program; in-situ characterization and inspection of tanks; multimedia environmental pollutant assessment system (MEPAS); LLNL wet oxidation -- AEA technology. Besides these articles, this publication covers: EU activities with Russia; technology transfer activities; and international organization activities.

  12. Project X RFQ EM Design

    SciTech Connect

    Romanov, Gennady; Hoff, Matthew; Li, Derun; Staples, John; Virostek, Steve; /LBNL

    2012-05-09

    Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H- ion source, a low-energy beam transport (LEBT), a CW 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the CW 162.5 MHz RFQ that provides bunching of the 1-10 mA H- beam with acceleration from 30 keV to 2.1 MeV.

  13. Longitudinal and Seasonal Variation of Lunar tide strength

    NASA Astrophysics Data System (ADS)

    Yizengaw, E.; Pacheco, E. E.; Valladares, C. E.

    2012-12-01

    It has been known since many decades that lunar tide, which manifests itself as a semi-diurnal wave that precesses through all local times within one lunar month, has been identified as a significant force that can produce a notable influence on the longitudinal equatorial density distribution and equatorial electrojet (EEJ). However, there has never been a comprehensive study, except some statistical analysis using the satellite based in-situ observations, of the lunar tide effect on a global scale. This left several questions, like the longitudinal and solar flux dependence of the lunar tide, the tidal wave strength difference between new and full moon phases, remained unanswered. The proximity of the Earth/Moon system to the Sun, proximity of a New/Full Moon to one of the nodes of the lunar orbit, and the proximity of a New/Full Moon to the perigee of the lunar orbit are among the main factors that can affect the seasonal variability of lunar tide strength. With the indications of lunar tide influence on the strength of dayside EEJ, enhancing EEJ's strength shortly after new and full moon, we utilize the ground-based magnetometer fourteen years (1998 - 2012) data and investigate the various aspects of lunar tide effects on the EEJ at three different longitudinal sectors. The equatorial magnetometers located at Jicamarca for American sector, Addis Ababa for African sector, and Tirunelveli for Indian sector are used for this comprehensive study. Simultaneously, using the GPS TEC data, we examined the lunar tide impacts on the equatorial density irregularities and bubble formations at different longitudinal sectors. We found surprising strong longitudinal dependence in the lunar tide strength and its influence on EEJ and density bubble formation. Significant solar flux and seasonal dependences in lunar tide strength have also been observed at all longitudinal sectors. Finally, we investigated the lunar tide strength difference between new moon and full moon phases.

  14. A dynamic trajectory class model for intensive longitudinal categorical outcome.

    PubMed

    Lin, Haiqun; Han, Ling; Peduzzi, Peter N; Murphy, Terrence E; Gill, Thomas M; Allore, Heather G

    2014-07-10

    This paper presents a novel dynamic latent class model for a longitudinal response that is frequently measured as in our prospective study of older adults with monthly data on activities of daily living for more than 10 years. The proposed method is especially useful when the longitudinal response is measured much more frequently than other relevant covariates. The trajectory classes are latent classes that represent distinct temporal patterns of the longitudinal response wherein an individual may remain in a trajectory class or switch to another as the class membership predictors are updated periodically over time. The identification of a common set of trajectory classes allows changes among the temporal patterns to be distinguished from local fluctuations in the response. Within a trajectory class, the longitudinal response is modeled by a class-specific generalized linear mixed model. An informative event such as death is jointly modeled by class-specific probability of the event through shared random effects with that for the longitudinal response. We do not impose the conditional independence assumption given the classes. We illustrate the method by analyzing the change over time in activities of daily living trajectory class among 754 older adults with 70,500 person-months of follow-up in the Precipitating Events Project. We also investigate the impact of jointly modeling the class-specific probability of the event on the parameter estimates in a simulation study. The primary contribution of our paper is the periodic updating of trajectory classes for a longitudinal categorical response without assuming conditional independence.

  15. The re-identification risk of Canadians from longitudinal demographics

    PubMed Central

    2011-01-01

    Background The public is less willing to allow their personal health information to be disclosed for research purposes if they do not trust researchers and how researchers manage their data. However, the public is more comfortable with their data being used for research if the risk of re-identification is low. There are few studies on the risk of re-identification of Canadians from their basic demographics, and no studies on their risk from their longitudinal data. Our objective was to estimate the risk of re-identification from the basic cross-sectional and longitudinal demographics of Canadians. Methods Uniqueness is a common measure of re-identification risk. Demographic data on a 25% random sample of the population of Montreal were analyzed to estimate population uniqueness on postal code, date of birth, and gender as well as their generalizations, for periods ranging from 1 year to 11 years. Results Almost 98% of the population was unique on full postal code, date of birth and gender: these three variables are effectively a unique identifier for Montrealers. Uniqueness increased for longitudinal data. Considerable generalization was required to reach acceptably low uniqueness levels, especially for longitudinal data. Detailed guidelines and disclosure policies on how to ensure that the re-identification risk is low are provided. Conclusions A large percentage of Montreal residents are unique on basic demographics. For non-longitudinal data sets, the three character postal code, gender, and month/year of birth represent sufficiently low re-identification risk. Data custodians need to generalize their demographic information further for longitudinal data sets. PMID:21696636

  16. Making use of longitudinal information in pattern recognition

    PubMed Central

    Lythgoe, David J.; Williams, Steven C.R.; Jokisch, Martha; Mönninghoff, Christoph; Streffer, Johannes; Jöckel, Karl‐Heinz; Weimar, Christian; Marquand, Andre F.

    2016-01-01

    Abstract Longitudinal designs are widely used in medical studies as a means of observing within‐subject changes over time in groups of subjects, thereby aiming to improve sensitivity for detecting disease effects. Paralleling an increased use of such studies in neuroimaging has been the adoption of pattern recognition algorithms for making individualized predictions of disease. However, at present few pattern recognition methods exist to make full use of neuroimaging data that have been collected longitudinally, with most methods relying instead on cross‐sectional style analysis. This article presents a principal component analysis‐based feature construction method that uses longitudinal high‐dimensional data to improve predictive performance of pattern recognition algorithms. The method can be applied to data from a wide range of longitudinal study designs and permits an arbitrary number of time‐points per subject. We apply the method to two longitudinal datasets, one containing subjects with mild cognitive impairment along with healthy controls, the other with early dementia subjects and healthy controls. Across both datasets, we show improvements in predictive accuracy relative to cross‐sectional classifiers for discriminating disease subjects from healthy controls on the basis of whole‐brain structural magnetic resonance image‐based voxels. In addition, we can transfer longitudinal information from one set of subjects to make disease predictions in another set of subjects. The proposed method is simple and, as a feature construction method, flexible with respect to the choice of classifier and image registration algorithm. Hum Brain Mapp 37:4385–4404, 2016. © 2016 Wiley Periodicals, Inc. PMID:27451934

  17. Model Selection Criteria for Missing-Data Problems Using the EM Algorithm.

    PubMed

    Ibrahim, Joseph G; Zhu, Hongtu; Tang, Niansheng

    2008-12-01

    We consider novel methods for the computation of model selection criteria in missing-data problems based on the output of the EM algorithm. The methodology is very general and can be applied to numerous situations involving incomplete data within an EM framework, from covariates missing at random in arbitrary regression models to nonignorably missing longitudinal responses and/or covariates. Toward this goal, we develop a class of information criteria for missing-data problems, called IC(H) (,) (Q), which yields the Akaike information criterion and the Bayesian information criterion as special cases. The computation of IC(H) (,) (Q) requires an analytic approximation to a complicated function, called the H-function, along with output from the EM algorithm used in obtaining maximum likelihood estimates. The approximation to the H-function leads to a large class of information criteria, called IC(H̃) (() (k) (),) (Q). Theoretical properties of IC(H̃) (() (k) (),) (Q), including consistency, are investigated in detail. To eliminate the analytic approximation to the H-function, a computationally simpler approximation to IC(H) (,) (Q), called IC(Q), is proposed, the computation of which depends solely on the Q-function of the EM algorithm. Advantages and disadvantages of IC(H̃) (() (k) (),) (Q) and IC(Q) are discussed and examined in detail in the context of missing-data problems. Extensive simulations are given to demonstrate the methodology and examine the small-sample and large-sample performance of IC(H̃) (() (k) (),) (Q) and IC(Q) in missing-data problems. An AIDS data set also is presented to illustrate the proposed methodology.

  18. Longitudinal cerebral blood flow and amyloid deposition: an emerging pattern?

    PubMed Central

    Sojkova, Jitka; Beason-Held, Lori; Zhou, Yun; An, Yang; Kraut, Michael A; Ye, Weigo; Ferrucci, Luigi; Mathis, Chester A; Klunk, William E; Wong, Dean F; Resnick, Susan M

    2008-01-01

    Although cerebral amyloid deposition may precede cognitive impairment by decades, the relationship between amyloid deposition and longitudinal change in neuronal function has not been studied. The aim of this paper is to determine whether nondemented individuals with high and low amyloid burden show different patterns of longitudinal regional cerebral blood flow (rCBF) changes in the years preceding measurement of amyloid deposition. Methods Twenty-eight nondemented participants (mean (SD) age at [11C] PIB 82.5(4.8) yrs; 6 mildly impaired) from the Baltimore Longitudinal Study of Aging underwent yearly resting-state [15O]H2O PET scans for up to 8 years. [11C]PIB images of amyloid deposition were acquired on average 10.8(0.8) years after the first CBF scan. [11C]PIB distribution volume ratios (DVR) of regions of interest were estimated by fitting a reference tissue model to the measured time activity curves. Based on mean cortical DVR, participants were divided into high and low [11C]PIB retention groups. Differences in longitudinal rCBF changes between high and low [11C]PIB groups were investigated by voxel-based analysis. Results Longitudinal rCBF changes differed significantly between high (n=10) and low (n=18) [11C]PIB groups (p<=0.001). Greater longitudinal decreases in rCBF in the high [11C]PIB group were seen in right anterior/mid cingulate, right supramarginal gyrus, left thalamus and midbrain bilaterally relative to the low group. Greater increases in rCBF over time in the high [11C]PIB group were found in left medial and inferior frontal gyri, right precuneus, left inferior parietal lobule, and the left postcentral gyrus. Conclusion In this group of nondemented older adults, those with high [11C]PIB show greater longitudinal declines in rCBF in certain areas, representing regions with greater decrements in neuronal function. Greater longitudinal increases in rCBF are also observed in those with higher amyloid load and may represent an attempt to preserve

  19. A Simple, Low Cost Longitudinal Phase Space Diagnostic

    SciTech Connect

    Bertsche, Kirk; Emma, Paul; Shevchenko, Oleg; /Novosibirsk, IYF

    2009-05-15

    For proper operation of the LCLS [1] x-ray free-electron laser (FEL), and other similar machines, measurement and control of the electron bunch longitudinal phase space is critical. The LCLS accelerator includes two bunch compressor chicanes to magnify the peak current. These magnetic chicanes can generate significant coherent synchrotron radiation (CSR), which can distort the phase space distribution. We propose a diagnostic scheme by exciting a weak skew quadrupole at an energy-chirped, high dispersion point in the first LCLS bunch compressor (BC1) to reconstruct longitudinal phase space on an OTR screen after BC1, allowing a time-resolved characterization of CSR effects.

  20. Ossification of the posterior longitudinal ligament: a case report

    PubMed Central

    Aker, PD; O’Connor, SM; Mior, SA; Beauchemin, D

    1989-01-01

    Ossification of the posterior longitudinal ligament (OPLL) has recently been recognized as a clinical entity. It is a rare condition, having a higher incidence in the Japanese population. It is characterized by hyperplasia of cartilage cells with eventual endochondral ossification of the posterior longitudinal ligament. The radiographic signs are characteristic and consist of a linear band of ossified tissue along the posterior margin of the vertebral body. OPLL can be associated with mild to serious neurological complications due to spinal cord or nerve root compression, or it may be asymptomatic. This paper reviews the radiological, clinical and therapeutic aspects of this rare condition. ImagesFigures 1 and 2Figures 3 and 4

  1. Longitudinal W boson scattering in a light scalar top scenario

    NASA Astrophysics Data System (ADS)

    Ishiwata, Koji; Yonekura, Yuki

    2017-07-01

    Scalar tops in the supersymmetric model affect the potential of the standard model-like Higgs at the quantum level. In light of the equivalence theorem, the deviation of the potential from the standard model can be traced by longitudinal gauge bosons. In this work, high-energy longitudinal W boson scattering is studied in a TeV-scale scalar top scenario. O (1 - 10 %) deviation from the standard model prediction in the differential cross section is found, depending on whether the observed Higgs mass is explained only by scalar tops or by additional contributions at a higher scale.

  2. Residuals analysis of the generalized linear models for longitudinal data.

    PubMed

    Chang, Y C

    2000-05-30

    The generalized estimation equation (GEE) method, one of the generalized linear models for longitudinal data, has been used widely in medical research. However, the related sensitivity analysis problem has not been explored intensively. One of the possible reasons for this was due to the correlated structure within the same subject. We showed that the conventional residuals plots for model diagnosis in longitudinal data could mislead a researcher into trusting the fitted model. A non-parametric method, named the Wald-Wolfowitz run test, was proposed to check the residuals plots both quantitatively and graphically. The rationale proposedin this paper is well illustrated with two real clinical studies in Taiwan.

  3. Longitudinal phase space experiments on the ELSA photoinjector

    SciTech Connect

    Dowell, D.H.; Joly, S.; Brion, J.P. de

    1995-12-31

    The excellent beam quality produced by RF photocathode injectors is well established, andhas been verified by numerous measurements of the transverse emittance. However, there are few experimental determinations of the longitudinal phase space. This paper reports on experiments performed at the ELSA FEL facility to emasure the longitudinal phase space distribution at the exit of the 144 MHz photoinjector cavity. Phase spaces were determined by the analysis of beam energy spectra and pulse shapes at 17.5 MeV for micropulse charges between 0.5 and 5 nC.

  4. Analysis and prediction of longitudinal stability of airplanes

    NASA Technical Reports Server (NTRS)

    Gilruth, R R; White, M D

    1941-01-01

    An analysis has been made of the longitudinal stability characteristics of 15 airplanes as determined in flight. In the correlation of satisfactory and unsatisfactory characteristics with determined values, the derivative that expresses the ratio of static-restoring moments to elevator-control moments was found to represent most nearly the stability characteristics appreciated by the pilots. The analysis was extended to study the effects of various design features on the observed stability characteristics. Design charts and data are included that show the effects on longitudinal stability of relative positions of wing and tail, fuselage size and location, engine nacelles, and horizontal-tail arrangements.

  5. NEIC Environmental Management System (EMS) Policy

    EPA Pesticide Factsheets

    National Enforcement Investigations Center (NEIC) Environmental Management System (EMS) Policy. Identification and management of actual and potential environmental impacts of operations and decisions for the purpose of continual improvement of performance

  6. EMS offshore. A new horizon for paramedics.

    PubMed

    Mallard, A S

    1991-10-01

    The difficulty in getting medical aid to offshore drilling platforms can be a source of life-threatening delays. Recently, some companies have charted new waters by actually stationing EMS crews on their rigs.

  7. Prospective Investigation of Video Game Use in Children and Subsequent Conduct Disorder and Depression Using Data from the Avon Longitudinal Study of Parents and Children.

    PubMed

    Etchells, Peter J; Gage, Suzanne H; Rutherford, Adam D; Munafò, Marcus R

    2016-01-01

    There is increasing public and scientific concern regarding the long-term behavioural effects of video game use in children, but currently little consensus as to the nature of any such relationships. We investigated the relationship between video game use in children, degree of violence in games, and measures of depression and a 6-level banded measure of conduct disorder. Data from the Avon Longitudinal Study of Parents and Children were used. A 3-level measure of game use at age 8/9 years was developed, taking into account degree of violence based on game genre. Associations with conduct disorder and depression, measured at age 15, were investigated using ordinal logistic regression, adjusted for a number of potential confounders. Shoot-em-up games were associated with conduct disorder bands, and with a binary measure of conduct disorder, although the strength of evidence for these associations was weak. A sensitivity analysis comparing those who play competitive games to those who play shoot-em-ups found weak evidence supporting the hypothesis that it is violence rather than competitiveness that is associated with conduct disorder. However this analysis was underpowered, and we cannot rule out the possibility that increasing levels of competition in games may be just as likely to account for the observed associations as violent content. Overall game exposure as indicated by number of games in a household was not related to conduct disorder, nor was any association found between shoot-em-up video game use and depression.

  8. Prospective Investigation of Video Game Use in Children and Subsequent Conduct Disorder and Depression Using Data from the Avon Longitudinal Study of Parents and Children

    PubMed Central

    Rutherford, Adam D.; Munafò, Marcus R.

    2016-01-01

    There is increasing public and scientific concern regarding the long-term behavioural effects of video game use in children, but currently little consensus as to the nature of any such relationships. We investigated the relationship between video game use in children, degree of violence in games, and measures of depression and a 6-level banded measure of conduct disorder. Data from the Avon Longitudinal Study of Parents and Children were used. A 3-level measure of game use at age 8/9 years was developed, taking into account degree of violence based on game genre. Associations with conduct disorder and depression, measured at age 15, were investigated using ordinal logistic regression, adjusted for a number of potential confounders. Shoot-em-up games were associated with conduct disorder bands, and with a binary measure of conduct disorder, although the strength of evidence for these associations was weak. A sensitivity analysis comparing those who play competitive games to those who play shoot-em-ups found weak evidence supporting the hypothesis that it is violence rather than competitiveness that is associated with conduct disorder. However this analysis was underpowered, and we cannot rule out the possibility that increasing levels of competition in games may be just as likely to account for the observed associations as violent content. Overall game exposure as indicated by number of games in a household was not related to conduct disorder, nor was any association found between shoot-em-up video game use and depression. PMID:26820149

  9. Separation-Individuation of Late Adolescents : A Longitudinal Study

    ERIC Educational Resources Information Center

    Aslan, Sevda; Gelbal, Selahattin

    2016-01-01

    The aim of this study was to demonstrate the change in separation-individuation between late adolescents in the first, second, third and fourth year of higher education. The study sample used for this longitudinal study consisted of 148 students attending class studies, computer education and science education departments of Kirikkale University.…

  10. A Longitudinal Study of Retirement in Older Male Veterans

    ERIC Educational Resources Information Center

    Schnurr, Paula P.; Lunney, Carole A.; Sengupta, Anjana; Spiro, Avron

    2005-01-01

    In this study, the authors examined the effect of retirement on psychological and physical symptoms in 404 older male veterans who were taking part in an ongoing longitudinal study. Hierarchical linear modeling was used to analyze symptom trajectories from preretirement, peri-retirement, and postretirement periods in veterans with either lifetime…

  11. Evaluating Digital Libraries: A Longitudinal and Multifaceted View.

    ERIC Educational Resources Information Center

    Marchionini, Gary

    2000-01-01

    The Perseus Digital Library (PDL), under continuous development since 1987, is one of the primary digital resources for the humanities. A summary of the PDL genesis and current status is given and the multifaceted and longitudinal evaluation effort is described. A brief synthesis of results is provided and reflections on the evaluation along with…

  12. A Longitudinal Study of Idiom and Text Comprehension

    ERIC Educational Resources Information Center

    Levorato, M. Chiara; Roch, Maja; Nesi, Barbara

    2007-01-01

    The relation between text and idiom comprehension in children with poor text comprehension skills was investigated longitudinally. In the first phase of the study, six-year-old first graders with different levels of text comprehension were compared in an idiom and sentence comprehension task. Text comprehension was shown to be more closely related…

  13. The Longitudinal Association between Oppositional and Depressive Symptoms across Childhood

    ERIC Educational Resources Information Center

    Boylan, Khrista; Georgiades, Katholiki; Szatmari, Peter

    2010-01-01

    Objective: Symptoms of oppositional defiant disorder (ODD) and depression show high rates of co-occurrence, both cross-sectionally and longitudinally. This study examines the extent to which variation in oppositional symptoms predict, variation in depressive symptoms over time, accounting for co-occurring depressive symptoms and measurement error.…

  14. A Longitudinal Assessment of the Victim-Offender Overlap

    ERIC Educational Resources Information Center

    Jennings, Wesley G.; Higgins, George E.; Tewksbury, Richard; Gover, Angela R.; Piquero, Alex R.

    2010-01-01

    Although research has established an offending/victimization overlap and that offenders and victims share similar characteristics, much less work has examined the longitudinal sequencing of victimization and offending in the same developmental period and whether key risk/protective factors significantly distinguish both offenders and victims. This…

  15. A Longitudinal Study of Accounting Students' Ethical Judgement Making Ability

    ERIC Educational Resources Information Center

    Mohamed Saat, Maisarah; Porter, Stacey; Woodbine, Gordon

    2012-01-01

    This paper reports the effect of a moral education programme on the ethical judgement making ability of university students. The programme comprises two forms of intervention: a dedicated ethics course and subsequent practical training. A total of 113 accounting students from six Malaysian universities participated in a longitudinal study…

  16. A Longitudinal Study of Relational and Physical Aggression in Preschool

    ERIC Educational Resources Information Center

    Crick, Nicki R.; Ostrov, Jamie M.; Burr, Jean E.; Cullerton-Sen, Crystal; Jansen-Yeh, Elizabeth; Ralston, Peter

    2006-01-01

    To understand the development of relational aggression during early childhood, 91 girls and boys ("M" age=39.0; "SD"=7.6 months) and their teachers participated in an 18-month longitudinal study. Children were observed for relational and physical aggression during free play in four time periods. Individually administered interviews were conducted…

  17. Longitudinal Effects of Domestic Violence on Employment and Welfare Outcomes

    ERIC Educational Resources Information Center

    Lindhorst, Taryn; Oxford, Monica; Gillmore, Mary Rogers

    2007-01-01

    This study uses longitudinal data spanning 13 years from a study of 234 adolescent mothers to evaluate the effects of cumulative domestic violence on employment and welfare use before and after welfare reform. Domestic violence increased the odds of unemployment after welfare reform, but not before; domestic violence had no effect on welfare use…

  18. Consistency and Development of Prosocial Dispositions: A Longitudinal Study.

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Guthrie, Ivanna K.; Murphy, Bridget C.; Shepard, Stephanie A.; Cumberland, Amanda; Carol, Gustavo

    1999-01-01

    Examined consistency in prosocial dispositions, using longitudinal data from preschool through early adulthood. Found that spontaneous prosocial behavior observed in preschools predicted actual prosocial behavior, other- and self-reported prosocial behavior, self-reported sympathy, and perspective taking in childhood to early adulthood. Prosocial…

  19. Longitudinal wave motion in width-constrained auxetic plates

    NASA Astrophysics Data System (ADS)

    Lim, Teik-Cheng

    2016-05-01

    This paper investigates the longitudinal wave velocity in auxetic plates in comparison to conventional ones, in which the plate is constrained from motion in the width direction. By taking into account the thickness change of the plate and its corresponding change in density, the developed wave velocity is casted not only as a function of Young’s modulus and density, but also in terms of Poisson’s ratio and longitudinal strain. Results show that density and thickness variations compensate for one another when the Poisson’s ratio is positive, but add up when the Poisson’s ratio is negative. Results also reveal that the classical model of longitudinal wave velocity for the plate is accurate when the Poisson’s ratio is about 1/3; at this Poisson’s ratio the influence from density and thickness variations cancel each other. Comparison between the current corrected model and the density-corrected Rayleigh-Lamb model reveals a number of consistent trends, while the discrepancies are elucidated. If the plate material possesses a negative Poisson’s ratio, the deviation of the actual wave velocity from the classical model becomes significant; auxeticity suppresses and enhances the wave velocity in compressive and tensile impacts, respectively. Hence the use of the corrected model is proposed when predicting longitudinal waves in width-constrained auxetic plates, and auxetic materials can be harnessed for effectively controlling wave velocities in thin-walled structures.

  20. Criminal Victimization and Crime Risk Perception: A Multilevel Longitudinal Study

    ERIC Educational Resources Information Center

    Russo, Silvia; Roccato, Michele; Vieno, Alessio

    2013-01-01

    In a national sample of the Italian population, surveyed four times between October 2002 and January 2007 (N = 2,008), we performed a multilevel longitudinal study aimed at predicting the increase in crime risk perception as a function of three families of independent variables, respectively lying at the within individual level (direct…

  1. Effects of First Occasion Test Experience on Longitudinal Cognitive Change

    ERIC Educational Resources Information Center

    Salthouse, Timothy A.

    2013-01-01

    Effects of additional test experience on longitudinal change in 5 cognitive abilities was examined in a sample of healthy adults ranging from 18 to 80 years of age. Participants receiving experience with parallel versions of the cognitive tests on the first occasion had more positive cognitive change an average of 2.5 years later than participants…

  2. 9. Photograph of a line drawing. SHEET 9, LONGITUDINAL SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Photograph of a line drawing. SHEET 9, LONGITUDINAL SECTION ON LINE AA; 9-16-1940. Assembly Building for Tank Plant for the Chrysler Corporation, Macomb County, Michigan. Delineator: E.B. - Detroit Arsenal, 6501 East Eleven Mile Road, Warren, Macomb County, MI

  3. Longitudinal Bidirectional Relations between Adolescents' Sympathy and Prosocial Behavior

    ERIC Educational Resources Information Center

    Carlo, Gustavo; Padilla-Walker, Laura M.; Nielson, Matthew G.

    2015-01-01

    Despite the importance of understanding sympathy and prosocial behaviors, research on the development of these tendencies in adolescence remains relatively sparse. In the present study, we examined age trends and bidirectional longitudinal relations in sympathy and prosocial behaviors across early to middle adolescents. Participants were 500…

  4. Two-Method Planned Missing Designs for Longitudinal Research

    ERIC Educational Resources Information Center

    Garnier-Villarreal, Mauricio; Rhemtulla, Mijke; Little, Todd D.

    2014-01-01

    We examine longitudinal extensions of the two-method measurement design, which uses planned missingness to optimize cost-efficiency and validity of hard-to-measure constructs. These designs use a combination of two measures: a "gold standard" that is highly valid but expensive to administer, and an inexpensive (e.g., survey-based)…

  5. LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

    SciTech Connect

    Luna-Cardozo, M.; Verth, G.; Erdelyi, R. E-mail: robertus@sheffield.ac.uk

    2012-04-01

    Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

  6. 14 CFR 27.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static longitudinal stability. 27.173 Section 27.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.173...

  7. 14 CFR 25.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static longitudinal stability. 25.173 Section 25.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173...

  8. 14 CFR 27.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static longitudinal stability. 27.173 Section 27.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.173...

  9. 14 CFR 25.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 25.173 Section 25.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173...

  10. 14 CFR 27.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static longitudinal stability. 27.173 Section 27.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.173...

  11. 14 CFR 27.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 27.173 Section 27.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.173...

  12. 14 CFR 25.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static longitudinal stability. 25.173 Section 25.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173...

  13. 14 CFR 25.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static longitudinal stability. 25.173 Section 25.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173...

  14. 14 CFR 27.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static longitudinal stability. 27.173 Section 27.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.173...

  15. 14 CFR 25.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static longitudinal stability. 25.173 Section 25.173 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173...

  16. Sensitivity Analysis of Mixed Models for Incomplete Longitudinal Data

    ERIC Educational Resources Information Center

    Xu, Shu; Blozis, Shelley A.

    2011-01-01

    Mixed models are used for the analysis of data measured over time to study population-level change and individual differences in change characteristics. Linear and nonlinear functions may be used to describe a longitudinal response, individuals need not be observed at the same time points, and missing data, assumed to be missing at random (MAR),…

  17. A Longitudinal Analysis of Television Advertising Effects on Adolescents.

    ERIC Educational Resources Information Center

    Moore, Roy L.; Moschis, George P.

    A longitudinal study examined both the short term and the long term effects of television advertising on the development of adolescents' consumption-related orientations. Questionnaires were administered to 556 adolescents in a number of schools in a southern state; a second wave of questionnaires was administered to a subsample of 230 of these…

  18. Minor Delinquency and Immigration: A Longitudinal Study among Male Adolescents

    ERIC Educational Resources Information Center

    Titzmann, Peter F.; Silbereisen, Rainer K.; Mesch, Gustavo

    2014-01-01

    On the basis of general theories of delinquency and the specific situation of immigrants, this longitudinal study investigated predictors of initial levels and rates of change in delinquency among 188 male ethnic German Diaspora immigrants from the former Soviet Union (FSU) in Germany, 237 male native German adolescents, and 182 male Jewish…

  19. Social Learning in a Longitudinal Integrated Clinical Placement

    ERIC Educational Resources Information Center

    Roberts, Chris; Daly, Michele; Held, Fabian; Lyle, David

    2017-01-01

    Recent research has demonstrated that longitudinal integrated placements (LICs) are an alternative mode of clinical education to traditional placements. Extended student engagement in community settings provide the advantages of educational continuity as well as increased service provision in underserved areas. Developing and maintaining LICs…

  20. Longitudinal Study of Low and High Achievers in Early Mathematics

    ERIC Educational Resources Information Center

    Navarro, Jose I.; Aguilar, Manuel; Marchena, Esperanza; Ruiz, Gonzalo; Menacho, Inmaculada; Van Luit, Johannes E. H.

    2012-01-01

    Background: Longitudinal studies allow us to identify, which specific maths skills are weak in young children, and whether there is a continuing weakness in these areas throughout their school years. Aims: This 2-year study investigated whether certain socio-demographic variables affect early mathematical competency in children aged 5-7 years.…

  1. Beyond Longitudinal Data: Causes, Consequences, Changes, and Continuity.

    ERIC Educational Resources Information Center

    Rutter, Michael

    1994-01-01

    Addresses strategies needed in using longitudinal data on psychopathology to test cause-and-effect relationships, including natural experiments, testing of competing hypotheses on mechanisms, study of reversal effects, multiple replications in different circumstances, use of designs to dissociate possible mechanisms, testing for dose-response…

  2. A Longitudinal Study of Individual and Organisational Learning

    ERIC Educational Resources Information Center

    Campbell, Timothy T.; Armstrong, Steven J.

    2013-01-01

    Purpose: The purpose of this paper is to empirically examine organisational learning (OL) and individual managerial learning and provide a comparative evaluation of the ability of each to generate organisational benefits. Design/methodology/approach: A theoretical model of organisational learning is developed which was then longitudinally tested…

  3. A Longitudinal Study of Judge Leniency and Consistency.

    ERIC Educational Resources Information Center

    Lunz, Mary E.; O'Neill, Thomas R.

    This retrospective longitudinal study was designed to show grading leniency patterns of judges within and across clinical examination administrations. Data from 17 different administrations of the histology examination of the American Society of Clinical Pathologists over 10 years were studied. Over the 10 years there were 4,683 candidates and 57…

  4. When Can Schools Affect Dropout Behavior? A Longitudinal Multilevel Analysis.

    ERIC Educational Resources Information Center

    Goldschmidt, Pete; Wang, Jia

    1999-01-01

    Used the National Education Longitudinal Study database to examine student and school factors associated with dropping out in different grades. Results show that the mix of student risk factors changes between early and late dropouts. School factors can account for approximately two-thirds of the difference in mean school dropout rates, but do not…

  5. Secondary Analysis of National Longitudinal Transition Study 2 Data

    ERIC Educational Resources Information Center

    Hicks, Tyler A.; Knollman, Greg A.

    2015-01-01

    This review examines published secondary analyses of National Longitudinal Transition Study 2 (NLTS2) data, with a primary focus upon statistical objectives, paradigms, inferences, and methods. Its primary purpose was to determine which statistical techniques have been common in secondary analyses of NLTS2 data. The review begins with an…

  6. Group Intervention for Dementia Family Caregivers: A Longitudinal Perspective.

    ERIC Educational Resources Information Center

    Haley, William E.

    1989-01-01

    Conducted longitudinal follow-up to previously published experimental study of effectiveness of group intervention for dementia family caregivers. Found methodological and clinical issues relevant to future studies included issues of differential attrition from treatment, selection of participants,and need for measures appropriate to long-term…

  7. The Third Wave of Longitudinal Data Systems: Data Partnerships

    ERIC Educational Resources Information Center

    Armstrong, Jane; Bergner, Terry; Smith, Nancy

    2008-01-01

    States have made dramatic progress in the past few years in implementing longitudinal data systems (LDS) to improve student achievement. These systems collect and house student educational data that make it easy for policymakers and practitioners to access and use it for reporting, policymaking and decision making. So much has happened in states…

  8. The Myers Longitudinal Medical Study. Monograph II. Final Report.

    ERIC Educational Resources Information Center

    McCaulley, Mary H.

    The Myers Longitudinal Medical Study is a five-stage investigation of the application of C.G. Jung's theory of psychological types to the understanding of medical student selection, achievement, and choices of specialty, professional employment and location of practice. Part I of this report describes the design and variables of the study, the…

  9. Longitudinal Associations among Child Maltreatment, Social Functioning, and Cortisol Regulation

    ERIC Educational Resources Information Center

    Alink, Lenneke R. A.; Cicchetti, Dante; Kim, Jungmeen; Rogosch, Fred A.

    2012-01-01

    Child maltreatment increases the risk for impaired social functioning and cortisol regulation. However, the longitudinal interplay among these factors is still unclear. This study aimed to shed light on the effect of maltreatment on social functioning and cortisol regulation over time. The sample consisted of 236 children (mean age 7.64 years, SD…

  10. Attachment from Infancy to Adulthood: The Major Longitudinal Studies

    ERIC Educational Resources Information Center

    Grossmann, Klaus E., Ed.; Grossmann, Karin, Ed.; Waters, Everett, Ed.

    2005-01-01

    This volume provides unique and valuable firsthand accounts of the most important longitudinal studies of attachment. Presented are a range of research programs that have broadened the understanding of early close relationships and their role in individual adaptation throughout life. In addition to discussing the findings that emerged from each…

  11. An Evaluation of PET Based on Longitudinal Data.

    ERIC Educational Resources Information Center

    Mandeville, Garrett K.

    Although teacher inservice programs based on Madeline Hunter's Program for Effective Teaching (PET) have become very popular in U.S. schools, there is little evidence that the Hunter model ultimately results in increased student achievement. This longitudinal study attempts to evaluate the effects of Hunter-based staff development programs on…

  12. 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…

  13. Suprasegmental Phonology Development and Reading Acquisition: A Longitudinal Study

    ERIC Educational Resources Information Center

    Calet, Nuria; Gutiérrez-Palma, Nicolás; Simpson, Ian C.; González-Trujillo, M. Carmen; Defior, Sylvia

    2015-01-01

    Previous studies implicate suprasegmental phonology in reading acquisition. However, little is known about how suprasegmental sensitivity develops or how it contributes to reading. Here, 130 Spanish primary-school children participated in this 2-year longitudinal study. Nonlinguistic rhythm, lexical-stress sensitivity and metrical-stress…

  14. Longitudinal Effects of Domestic Violence on Employment and Welfare Outcomes

    ERIC Educational Resources Information Center

    Lindhorst, Taryn; Oxford, Monica; Gillmore, Mary Rogers

    2007-01-01

    This study uses longitudinal data spanning 13 years from a study of 234 adolescent mothers to evaluate the effects of cumulative domestic violence on employment and welfare use before and after welfare reform. Domestic violence increased the odds of unemployment after welfare reform, but not before; domestic violence had no effect on welfare use…

  15. Violence Viewing and Adolescent Aggression: A Longitudinal Study.

    ERIC Educational Resources Information Center

    Viemero, Vappu

    A longitudinal field study conducted in Turku, Finland, traced the development of aggression as a function of the viewing of violence by children from the ages of 7 and 9 to the ages of 15 and 17 to explore the connection between violence viewing and viewers' aggression, and to shed light on the question of causality. The 220 subjects, both male…

  16. Longitudinal and Transverse Inelastic Electron Scattering from 56Fe

    NASA Astrophysics Data System (ADS)

    Altemus, R.; Cafolla, A.; Day, D.; McCarthy, J. S.; Whitney, R. R.; Wise, J. E.

    1980-04-01

    Inelastic-electron-scattering cross sections for 56Fe have been measured in the continuum region. The longitudinal and transverse inelastic response functions have been determined for vector momentum transfers, q, from 210-410 MeV/c and for energy losses 0<ω<=220 MeV.

  17. Language Acquisition after Mutism: A Longitudinal Case Study of Autism.

    ERIC Educational Resources Information Center

    Windsor, Jennifer; And Others

    1994-01-01

    This longitudinal case study follows the development of a woman with autism from mutism at age 10 to acquisition of a range of spoken and written language skills by age 26. Results support hypotheses that both spoken and written language may become feasible forms of communication in such cases, although some skills may plateau or decline.…

  18. Longitudinal Links between Early Coparenting and Infant Behaviour Problems

    ERIC Educational Resources Information Center

    LeRoy, Michelle; Mahoney, Annette; Pargament, Kenneth I.; DeMaris, Alfred

    2013-01-01

    This study of 164 married couples examined longitudinal links between parents' perceptions of coparenting support and undermining by spouse at 6 months postpartum and infant behaviour problems at the age of 12 months after controlling for marital quality, individual parenting, and infant temperament. Multiple methods (i.e. parent reports and…

  19. Microscopic observations during longitudinal compression loading of single pulp fibers

    Treesearch

    Irving B. Sachs

    1986-01-01

    Paperboard components (linerboard adn corrugating medium) fail in edgewise compression because of failure of single fibers, as well as fiber-to-fiber bonds. While fiber-to-fiber-bond failure has been studied extensively, little is known about the longitudinal compression failure of a single fiber. In this study, surface alterations on single loblolly pine kraft pulp...

  20. Structural Damage Detection Using Slopes of Longitudinal Vibration Shapes

    DOE PAGES

    Xu, W.; Zhu, W. D.; Smith, S. A.; ...

    2016-03-18

    While structural damage detection based on flexural vibration shapes, such as mode shapes and steady-state response shapes under harmonic excitation, has been well developed, little attention is paid to that based on longitudinal vibration shapes that also contain damage information. This study originally formulates a slope vibration shape for damage detection in bars using longitudinal vibration shapes. To enhance noise robustness of the method, a slope vibration shape is transformed to a multiscale slope vibration shape in a multiscale domain using wavelet transform, which has explicit physical implication, high damage sensitivity, and noise robustness. These advantages are demonstrated in numericalmore » cases of damaged bars, and results show that multiscale slope vibration shapes can be used for identifying and locating damage in a noisy environment. A three-dimensional (3D) scanning laser vibrometer is used to measure the longitudinal steady-state response shape of an aluminum bar with damage due to reduced cross-sectional dimensions under harmonic excitation, and results show that the method can successfully identify and locate the damage. Slopes of longitudinal vibration shapes are shown to be suitable for damage detection in bars and have potential for applications in noisy environments.« less

  1. Structural Damage Detection Using Slopes of Longitudinal Vibration Shapes

    SciTech Connect

    Xu, W.; Zhu, W. D.; Smith, S. A.; Cao, M. S.

    2016-03-18

    While structural damage detection based on flexural vibration shapes, such as mode shapes and steady-state response shapes under harmonic excitation, has been well developed, little attention is paid to that based on longitudinal vibration shapes that also contain damage information. This study originally formulates a slope vibration shape for damage detection in bars using longitudinal vibration shapes. To enhance noise robustness of the method, a slope vibration shape is transformed to a multiscale slope vibration shape in a multiscale domain using wavelet transform, which has explicit physical implication, high damage sensitivity, and noise robustness. These advantages are demonstrated in numerical cases of damaged bars, and results show that multiscale slope vibration shapes can be used for identifying and locating damage in a noisy environment. A three-dimensional (3D) scanning laser vibrometer is used to measure the longitudinal steady-state response shape of an aluminum bar with damage due to reduced cross-sectional dimensions under harmonic excitation, and results show that the method can successfully identify and locate the damage. Slopes of longitudinal vibration shapes are shown to be suitable for damage detection in bars and have potential for applications in noisy environments.

  2. Longitudinal Evaluation of the Brighter Futures Program. Final Report.

    ERIC Educational Resources Information Center

    Emihovich, Catherine; Davis, Terry

    This report provides information on the longitudinal evaluation of the Brighter Futures program in Florida, a teen pregnancy prevention program which created support groups for mothers age 16 and younger in order to prevent their having second pregnancies. Other program goals were to ensure that the girls finish high school and plan for a career,…

  3. A Longitudinal Investigation of Commitment Dynamics in Cohabiting Relationships

    ERIC Educational Resources Information Center

    Rhoades, Galena K.; Stanley, Scott M.; Markman, Howard J.

    2012-01-01

    This longitudinal study followed 120 cohabiting, opposite-sex couples over 8 months to test hypotheses derived from commitment theory about how two types of commitment (dedication and constraint) operate during cohabitation. In nearly half the couples, there were large differences between partners in terms of dedication. These differences were…

  4. Longitudinal Effects of Parental Bereavement on Adolescent Developmental Competence

    ERIC Educational Resources Information Center

    Brent, David A.; Melhem, Nadine M.; Masten, Ann S.; Porta, Giovanna; Walker Payne, Monica

    2012-01-01

    The aim of this study is to assess the impact of sudden parental bereavement on subsequent attainment of developmental competencies. This longitudinal study reports on 126 youth bereaved by sudden parental death (suicide, accident, or natural death) and 116 demographically similar nonbereaved controls assessed at 9, 21, 33, and 62 months after…

  5. Gender Differences in Identity Development: An Examination of Longitudinal Data.

    ERIC Educational Resources Information Center

    Streitmatter, Janice

    1993-01-01

    Analyzed longitudinal data from 105 students when they were in junior high and high school to examine relationship between gender and identity development over time. Results indicated that patterns of change over time were similar for males and females; as students aged, they grew in psychosocial maturity regardless of gender. (Author/NB)

  6. Advanced Issues in Propensity Scores: Longitudinal and Missing Data

    ERIC Educational Resources Information Center

    Kupzyk, Kevin A.; Beal, Sarah J.

    2017-01-01

    In order to investigate causality in situations where random assignment is not possible, propensity scores can be used in regression adjustment, stratification, inverse-probability treatment weighting, or matching. The basic concepts behind propensity scores have been extensively described. When data are longitudinal or missing, the estimation and…

  7. A Longitudinal Study of Accounting Students' Ethical Judgement Making Ability

    ERIC Educational Resources Information Center

    Mohamed Saat, Maisarah; Porter, Stacey; Woodbine, Gordon

    2012-01-01

    This paper reports the effect of a moral education programme on the ethical judgement making ability of university students. The programme comprises two forms of intervention: a dedicated ethics course and subsequent practical training. A total of 113 accounting students from six Malaysian universities participated in a longitudinal study…

  8. Stability of Career Aspirations: A Longitudinal Test of Gottfredson's Theory

    ERIC Educational Resources Information Center

    Junk, Kate E.; Armstrong, Patrick Ian

    2010-01-01

    Gottfredson's theory of the career compromise process was evaluated using a longitudinal data set of 2,353 female and 321 male students recruited for Zuckerman's "Seven College Study," who reported their career aspirations twice over a 1-year period. Expressed career aspirations were coded on the dimensions of sex type, prestige, and the…

  9. Longitudinal Bidirectional Relations between Adolescents' Sympathy and Prosocial Behavior

    ERIC Educational Resources Information Center

    Carlo, Gustavo; Padilla-Walker, Laura M.; Nielson, Matthew G.

    2015-01-01

    Despite the importance of understanding sympathy and prosocial behaviors, research on the development of these tendencies in adolescence remains relatively sparse. In the present study, we examined age trends and bidirectional longitudinal relations in sympathy and prosocial behaviors across early to middle adolescents. Participants were 500…

  10. Anxiety Sensitivity and Panic Attacks: A 1-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Li, Wen; Zinbarg, Richard E.

    2007-01-01

    The hypothesis that anxiety sensitivity (AS) is a risk factor for panic genesis has obtained compelling support, but the clinical/practical importance of AS in panic genesis has been questioned. In addition, the association between panic experience and AS increase has not been clearly demonstrated. Through this 1-year longitudinal study among…

  11. Longitudinal Associations among Child Maltreatment, Social Functioning, and Cortisol Regulation

    ERIC Educational Resources Information Center

    Alink, Lenneke R. A.; Cicchetti, Dante; Kim, Jungmeen; Rogosch, Fred A.

    2012-01-01

    Child maltreatment increases the risk for impaired social functioning and cortisol regulation. However, the longitudinal interplay among these factors is still unclear. This study aimed to shed light on the effect of maltreatment on social functioning and cortisol regulation over time. The sample consisted of 236 children (mean age 7.64 years, SD…

  12. A Longitudinal Study Assessing the Microsoft Office Skills Course

    ERIC Educational Resources Information Center

    Carpenter, Donald A.; McGinnis, Denise; Slauson, Gayla Jo; Snyder, Johnny

    2013-01-01

    This paper explains a four-year longitudinal study of the assessment process for a Microsoft Office skills course. It examines whether there is an increase in students' knowledge based on responses to pre- and post-surveys that asked students to evaluate how well they can do particular tasks. Classical classroom teaching methods were used in the…

  13. 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

  14. Using Longitudinal Scales Assessment for Instrumental Music Students

    ERIC Educational Resources Information Center

    Simon, Samuel H.

    2014-01-01

    In music education, current assessment trends emphasize student reflection, tracking progress over time, and formative as well as summative measures. This view of assessment requires instrumental music educators to modernize their approaches without interfering with methods that have proven to be successful. To this end, the Longitudinal Scales…

  15. A Longitudinal Study of the Impact of an Environmental Action

    ERIC Educational Resources Information Center

    Rioux, Liliane; Pasquier, Daniel

    2013-01-01

    In a previous study, we investigated the impact of an awareness-raising campaign on the behaviour of secondary school children in the Centre Region of France, regarding the recycling of used batteries. But, was it a question of pro-environmental behaviour or simply an environmental action? To answer this question, a three-year longitudinal study…

  16. Longitudinal Monitoring of Public Reactions to the U.S

    Treesearch

    J.D. Absher; A.G. Graefe; R.C. Burns

    2008-01-01

    Natural resource managers need to better understand the impact of fees on outdoor recreationists. The debate about recreation fees involves both operational issues such as revenue use and social issues such as justice and fairness. The recreation fee program of the US Forest Service is over ten years old and it is now possible to gauge some of the longitudinal effects...

  17. Longitudinal Effects of Parental Bereavement on Adolescent Developmental Competence

    ERIC Educational Resources Information Center

    Brent, David A.; Melhem, Nadine M.; Masten, Ann S.; Porta, Giovanna; Walker Payne, Monica

    2012-01-01

    The aim of this study is to assess the impact of sudden parental bereavement on subsequent attainment of developmental competencies. This longitudinal study reports on 126 youth bereaved by sudden parental death (suicide, accident, or natural death) and 116 demographically similar nonbereaved controls assessed at 9, 21, 33, and 62 months after…

  18. Conduct, Biological Factors and Adult Delinquency in a Longitudinal Perspective.

    ERIC Educational Resources Information Center

    Magnusson, David

    In the course of a longitudinal research program conducted in Sweden, data were being collected on biological and psychological aspects of individual functioning and on environmental factors for a fairly large representative sample (approximately 1,000) of Swedish males and females between 10 and 27 years of age. Based on data from the…

  19. A Longitudinal Study of the Impact of an Environmental Action

    ERIC Educational Resources Information Center

    Rioux, Liliane; Pasquier, Daniel

    2013-01-01

    In a previous study, we investigated the impact of an awareness-raising campaign on the behaviour of secondary school children in the Centre Region of France, regarding the recycling of used batteries. But, was it a question of pro-environmental behaviour or simply an environmental action? To answer this question, a three-year longitudinal study…

  20. Secondary Analysis of National Longitudinal Transition Study 2 Data

    ERIC Educational Resources Information Center

    Hicks, Tyler A.; Knollman, Greg A.

    2015-01-01

    This review examines published secondary analyses of National Longitudinal Transition Study 2 (NLTS2) data, with a primary focus upon statistical objectives, paradigms, inferences, and methods. Its primary purpose was to determine which statistical techniques have been common in secondary analyses of NLTS2 data. The review begins with an…