Total volume versus bouts

DEFF Research Database (Denmark)

Chinapaw, Mai; Klakk, Heidi; Møller, Niels Christian

2018-01-01

BACKGROUND/OBJECTIVES: Examine the prospective relationship of total volume versus bouts of sedentary behaviour (SB) and moderate-to-vigorous physical activity (MVPA) with cardiometabolic risk in children. In addition, the moderating effects of weight status and MVPA were explored. SUBJECTS....../METHODS: Longitudinal study including 454 primary school children (mean age 10.3 years). Total volume and bouts (i.e. ≥10 min consecutive minutes) of MVPA and SB were assessed by accelerometry in Nov 2009/Jan 2010 (T1) and Aug/Oct 2010 (T2). Triglycerides, total cholesterol/HDL cholesterol ratio (TC:HDLC ratio......, with or without mutual adjustments between MVPA and SB. The moderating effects of weight status and MVPA (for SB only) were examined by adding interaction terms. RESULTS: Children engaged daily in about 60 min of total MVPA and 0-15 min/week in MVPA bouts. Mean total sedentary time was around 7 h/day with over 3...

Risk factors for postoperative complications after total laryngectomy following radiotherapy or chemoradiation

DEFF Research Database (Denmark)

Wulff, N B; Kristensen, C.A.; Andersen, E

2015-01-01

OBJECTIVES: To determine the rates of and risk factors for postoperative complications following total laryngectomy in patients treated with radiotherapy or chemoradiation. DESIGN: Retrospective longitudinal study. SETTING: Tertiary medical centres. PARTICIPANTS: A total of 143 patients undergoin...

Pain after sternotomy – review

Directory of Open Access Journals (Sweden)

Ana Paula Santana Huang

2016-07-01

Full Text Available Background and objective: Adequate analgesia after sternotomy reduces postoperative adverse events. There are various methods of treating pain after heart surgery, such as infiltration with a local anesthetic, nerve block, opioids, non-steroidal anti-inflammatory drugs, alpha-adrenergic agents, intrathecal and epidural techniques, and multimodal analgesia. Content: A review of the epidemiology, pathophysiology, prevention and treatment of pain after sternotomy. We also discuss the various analgesic therapeutic modalities, emphasizing advantages and disadvantages of each technique. Conclusions: Heart surgery is performed mainly via medium sternotomy, which results in significant postoperative pain and a non-negligible incidence of chronic pain. Effective pain control improves patient satisfaction and clinical outcomes. There is no clearly superior technique. It is believed that a combined multimodal analgesic regimen (using different techniques is the best approach for treating postoperative pain, maximizing analgesia and reducing side effects. Resumo: Justificativa e objetivo: Analgesia adequada após esternotomia reduz eventos adversos no pós-operatório. Várias modalidades estão disponíveis para tratamento da dor após cirurgia cardíaca: infiltração com anestésico local, bloqueio de nervos, opioides, anti-inflamatórios não esteroidais, agentes alfa-adrenérgicos, técnicas intratecais e epidurais e analgesia multimodal. Conteúdo: Foi feita uma revisão sobre epidemiologia, fisiopatologia, prevenção e tratamento da dor após esternotomia. Também fora discutidas as diversas modalidades terapêuticas analgésicas, com ênfase em vantagens e desvantagens de cada técnica. Conclusões: A cirurgia cardíaca é feita principalmente por esternotomia média, que resulta em dor significativa no pós-operatório e uma incidência não insignificante de dor crônica. O controle efetivo da dor melhora a satisfação dos pacientes e os

Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification.

Science.gov (United States)

Reuschel, Anna; Bogatsch, Holger; Barth, Thomas; Wiedemann, Renate

2010-11-01

To compare the intraoperative and postoperative outcomes of conventional longitudinal phacoemulsification and torsional phacoemulsification. Department of Ophthalmology, University of Leipzig, Germany. Randomized single-center clinical trial. Eyes with senile cataract were randomized to have phacoemulsification using the Infiniti Vision System and the torsional mode (OZil) or conventional longitudinal mode. Primary outcomes were corrected distance visual acuity (CDVA) and central endothelial cell density (ECD), calculated according to the Conference on Harmonisation-E9 Guidelines in which missing values were substituted by the median in each group (primary analysis) and the loss was then calculated using actual data (secondary analysis). Secondary outcomes were ultrasound (US) time, cumulative dissipated energy (CDE), and percentage total equivalent power in position 3. Postoperative follow-up was at 3 months. The mean preoperative CDVA was 0.41 logMAR in the torsional group and 0.38 logMAR in the longitudinal group, improving to 0.07 logMAR postoperatively in both groups. The mean ECD loss was 7.2% ± 4.6% in the torsional group (72 patients) and 7.1% ± 4.4% in the longitudinal group (76 patients), with no statistically significant differences in the primary analysis (P = .342) or secondary analysis (P = .906). The mean US time, CDE, and percentage total equivalent power in position 3 were statistically significantly lower in the torsional group (98 patients) than in the longitudinal group (94 patients) (P<.001). The torsional mode was as safe as the longitudinal mode in phacoemulsification for age-related cataract. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Applied longitudinal analysis

CERN Document Server

Fitzmaurice, Garrett M; Ware, James H

2012-01-01

Praise for the First Edition "". . . [this book] should be on the shelf of everyone interested in . . . longitudinal data analysis.""-Journal of the American Statistical Association   Features newly developed topics and applications of the analysis of longitudinal data Applied Longitudinal Analysis, Second Edition presents modern methods for analyzing data from longitudinal studies and now features the latest state-of-the-art techniques. The book emphasizes practical, rather than theoretical, aspects of methods for the analysis of diverse types of lo

Restoration of longitudinal images.

Science.gov (United States)

Hu, Y; Frieden, B R

1988-01-15

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

Comportamento da dor e da função pulmonar em pacientes submetidos à cirurgia cardíaca via esternotomia Pain and pulmonary function in patients submitted to heart surgery via sternotomy

Directory of Open Access Journals (Sweden)

Maria Cristina dos Santos Baumgarten

2009-12-01

Full Text Available OBJETIVO: Avaliar o comportamento da função pulmonar e da dor em pacientes adultos submetidos à cirurgia cardíaca por esternotomia. Além de verificar possíveis correlações e comparações dessas variáveis com as características do procedimento cirúrgico e o tempo de internação hospitalar. MÉTODOS: Foi realizado estudo de coorte composto de 70 indivíduos, nos quais foi avaliada a função pulmonar préoperatória por espirometria e inspirometria de incentivo. Os pacientes foram acompanhados no pós-operatório, por meio de protocolo com informações da cirurgia, função pulmonar e um protocolo de avaliação álgica (escala análoga visual e desenho do corpo humano. RESULTADOS: Os valores de função pulmonar do período pós-operatório apresentaram diminuição significativa em relação ao pré-operatório (POBJECTIVE: To investigate the pulmonary function and pain in adult patients undergoing heart surgery via sternotomy and to verify possible correlations of these variables with the characteristics of the surgical procedure and hospital stay. METHODS: A cross-sectional study was carried out of 70 individuals undergoing heart surgery. The lung function was assessed before and after surgery by spirometry and incentive spirometry. Details of the surgical procedure were studied and patients were followed up postoperatively using a visual analogue scale and design of the human body to evaluate pain. RESULTS: The pulmonary function was significantly impaired in the postoperative compared to preoperative period (P <0.01. The pain was centered in the region of the sternotomy and persisted until at least the 5th postoperative day. There was a correlation between pain and the parameters of pulmonary function (forced expiratory volume in 1 second - percentage: r = -0.271, P <0.047; peak expiratory flow: r = 0.357, P <0.008; and maximum inspiratory volume: r = -0.293, P <0.032. There was no significant correlation between pain and other

Combining Near-Subject Absolute and Relative Measures of Longitudinal Hydration in Hemodialysis

OpenAIRE

Chan, Cian; McIntyre, Christopher; Smith, David; Spanel, Patrik; Davies, Simon J.

2009-01-01

Background and objectives: The feasibility and additional value of combining bioimpedance analysis (BIA) with near-subject absolute measurement of total body water using deuterium dilution (TBWD) in determining longitudinal fluid status was investigated.

On the infrared sensitivity of the longitudinal cross section in e+e- annihilation

International Nuclear Information System (INIS)

Beneke, M.

1996-09-01

The authors have calculated the contributions proportional to β 0 n α s n+1 to the longitudinal fragmentation function in e + e - annihilation to all orders of perturbation theory. They use this result to estimate higher-order perturbative corrections and nonperturbative corrections to the longitudinal cross section σ L and discuss the prospects of determining α s from σ L . The structure of infrared renormalons in the perturbative expansion suggests that the longitudinal cross section for hadron production with fixed momentum fraction x receives nonperturbative contributions of order 1/(x 2 Q 2 ), whereas the total cross section has a larger, 1/Q correction. This correction arises from very large longitudinal distances and is related to the behavior of the Borel integral for the cross section with fixed x at large values of the Borel parameter

A Longitudinal Study of Accounting Students' Ethical Judgement Making Ability

Science.gov (United States)

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…

Emittance growth of an electron beam in a periodic channel due to transfer of longitudinal energy to transverse energy

International Nuclear Information System (INIS)

Carlsten, B.E.

1998-01-01

Most discussions about emittance growth and halo production for an intense electron beam in a periodic focusing channel assume that the total transverse energy is constant (or, in other words, that the transverse and longitudinal Hamiltonians are separable). Previous analyses that include variations in the total transverse energy are typically based on a transverse-longitudinal coupling that is either from two-dimensional space-charge modes or particle-particle Coulomb collisions. With the space-charge modes, the energy exchange between the transverse and longitudinal directions is periodic, and of constant magnitude. The total energy transfer for the case of the Coulomb collisions is negligible. This limited increase of energy in the transverse direction from these other effects will limit the amount of transverse emittance growth possible. In this paper, the authors investigate a mechanism in which there is a continual transfer of energy from the longitudinal direction to the transverse direction, leading to essentially unlimited potential transverse emittance growth. This mechanism is caused by an asymmetry of the beam's betatron motion within the periodic focusing elements. This analysis is based on thermodynamic principles. This mechanism exists for both solenoids and quadrupole focusing, although only solenoid focusing is studied here

Estimating correlation between multivariate longitudinal data in the presence of heterogeneity.

Science.gov (United States)

Gao, Feng; Philip Miller, J; Xiong, Chengjie; Luo, Jingqin; Beiser, Julia A; Chen, Ling; Gordon, Mae O

2017-08-17

Estimating correlation coefficients among outcomes is one of the most important analytical tasks in epidemiological and clinical research. Availability of multivariate longitudinal data presents a unique opportunity to assess joint evolution of outcomes over time. Bivariate linear mixed model (BLMM) provides a versatile tool with regard to assessing correlation. However, BLMMs often assume that all individuals are drawn from a single homogenous population where the individual trajectories are distributed smoothly around population average. Using longitudinal mean deviation (MD) and visual acuity (VA) from the Ocular Hypertension Treatment Study (OHTS), we demonstrated strategies to better understand the correlation between multivariate longitudinal data in the presence of potential heterogeneity. Conditional correlation (i.e., marginal correlation given random effects) was calculated to describe how the association between longitudinal outcomes evolved over time within specific subpopulation. The impact of heterogeneity on correlation was also assessed by simulated data. There was a significant positive correlation in both random intercepts (ρ = 0.278, 95% CI: 0.121-0.420) and random slopes (ρ = 0.579, 95% CI: 0.349-0.810) between longitudinal MD and VA, and the strength of correlation constantly increased over time. However, conditional correlation and simulation studies revealed that the correlation was induced primarily by participants with rapid deteriorating MD who only accounted for a small fraction of total samples. Conditional correlation given random effects provides a robust estimate to describe the correlation between multivariate longitudinal data in the presence of unobserved heterogeneity (NCT00000125).

Longitudinal correlates of change in blood pressure in adolescent girls

NARCIS (Netherlands)

Daniels, [No Value; McMahon, RP; Obarzanek, E; Waclawiw, MA; Similo, SL; Biro, FM; Schreiber, GB; Kimm, SYS; Morrison, JA; Barton, BA

The objective of this study was to assess the longitudinal changes in blood pressure in black and white adolescent girls and evaluate potential determinants of changes in blood pressure, including sexual maturation and body size. A total of 1213 black and 1166 white girls, ages 9 or 10 years at

First Measurement of Charged Current Cross Sections at HERA with Longitudinally Polarised Positrons

CERN Document Server

Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reisert, B.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2006-01-01

Data taken with positrons of different longitudinal polarisation states in collision with unpolarised protons at HERA are used to measure the total cross sections of the charged current process, e^+ p \\to \\bar{\

Exploring Longitudinal Risk-return Relationships

DEFF Research Database (Denmark)

Andersen, Torben J.; Bettis, Richard A.

2015-01-01

We study a longitudinal fit model of adaptation and its association with the longitudinal risk-return relationship. The model allows the firm to adjust its position in response to partial learning about a changing environment characterized by two path-dependent processes—a random walk and a stoch......We study a longitudinal fit model of adaptation and its association with the longitudinal risk-return relationship. The model allows the firm to adjust its position in response to partial learning about a changing environment characterized by two path-dependent processes—a random walk...... can lead to the inverse longitudinal risk-return relationships observed empirically. We discuss this apparent paradox and the possible resolution between mindless and conscious behavior as plausible causes of the longitudinal Bowman Paradox....

Longitudinal On-Column Thermal Modulation for Comprehensive Two-Dimensional Liquid Chromatography.

Science.gov (United States)

Creese, Mari E; Creese, Mathew J; Foley, Joe P; Cortes, Hernan J; Hilder, Emily F; Shellie, Robert A; Breadmore, Michael C

2017-01-17

Longitudinal on-column thermal modulation for comprehensive two-dimensional liquid chromatography is introduced. Modulation optimization involved a systematic investigation of heat transfer, analyte retention, and migration velocity at a range of temperatures. Longitudinal on-column thermal modulation was realized using a set of alkylphenones and compared to a conventional valve-modulator employing sample loops. The thermal modulator showed a reduced modulation-induced pressure impact than valve modulation, resulting in reduced baseline perturbation by a factor of 6; yielding a 6-14-fold improvement in signal-to-noise. A red wine sample was analyzed to demonstrate the potential of the longitudinal on-column thermal modulator for separation of a complex sample. Discrete peaks in the second dimension using the thermal modulator were 30-55% narrower than with the valve modulator. The results shown herein demonstrate the benefits of an active focusing modulator, such as reduced detection limits and increased total peak capacity.

Understanding why people do or do not engage in activities following total joint replacement: a longitudinal qualitative study.

Science.gov (United States)

Webster, F; Perruccio, A V; Jenkinson, R; Jaglal, S; Schemitsch, E; Waddell, J P; Venkataramanan, V; Bytautas, J; Davis, A M

2015-06-01

Numerous studies report large and significant improvements in basic mobility and activities of daily living following total hip or knee replacement (TJR). Nevertheless, quantitative research has shown minimal increase in participation in activities that benefit overall health. This study explored why people do or do not engage in activities following hip or knee TJR. This was a longitudinal qualitative study. Sampling was guided by constructivist grounded theory and data collected using open-ended, semi-structured interviews. Participants were recruited using maximum variation sampling based on age, sex and joint replaced (hip or knee). Data were analysed using a constant comparative approach and coded for thematic patterns and relationships from which overarching themes were constructed. Twenty-nine patients participated in interviews prior to, and 8 and 18 months post following TJR. A high degree of variability with regard to participants' return to activities was found and five emergent themes were identified that accounted for this variability. These themes highlight the importance of issues beyond medical factors alone, such as socio-cultural factors that partially determine participants' participation in activity following TJR. Findings suggest that multi-faceted experiences impact participation in activity following TJR. These experiences include changes in identity and lifestyle that preclude a 'return to normal'. There is an urgent need for supports to increase people's activity post-TJR in order to facilitate enhancement of post-surgery levels of engagement. Approaches that take into consideration more personalized interventions may be critical to promoting healthy aging in people with TJR. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Longitudinal categorical data analysis

CERN Document Server

Sutradhar, Brajendra C

2014-01-01

This is the first book in longitudinal categorical data analysis with parametric correlation models developed based on dynamic relationships among repeated categorical responses. This book is a natural generalization of the longitudinal binary data analysis to the multinomial data setup with more than two categories. Thus, unlike the existing books on cross-sectional categorical data analysis using log linear models, this book uses multinomial probability models both in cross-sectional and longitudinal setups. A theoretical foundation is provided for the analysis of univariate multinomial responses, by developing models systematically for the cases with no covariates as well as categorical covariates, both in cross-sectional and longitudinal setups. In the longitudinal setup, both stationary and non-stationary covariates are considered. These models have also been extended to the bivariate multinomial setup along with suitable covariates. For the inferences, the book uses the generalized quasi-likelihood as w...

A Longitudinal Study of Total Quality Management Processes in Business Colleges.

Science.gov (United States)

Vazzana, Gary; Elfrink, John; Bachmann, Duane P.

2000-01-01

Surveys of business school deans in 1995 (n=243) and 1998 (n=151) regarding total quality management (TQM) practices revealed increases in mission and strategy development, goal setting, and use of advisory boards and cross-functional teams. Few are using TQM to manage core learning processes. (SK)

Inducible displacement of cemented tibial components ten years after total knee arthroplasty.

Science.gov (United States)

Lam Tin Cheung, K; Lanting, B A; McCalden, R W; Yuan, X; MacDonald, S J; Naudie, D D; Teeter, M G

2018-02-01

The aim of this study was to evaluate the long-term inducible displacement of cemented tibial components ten years after total knee arthroplasty (TKA). A total of 15 patients from a previously reported prospective trial of fixation using radiostereometric analysis (RSA) were examined at a mean of 11 years (10 to 11) postoperatively. Longitudinal supine RSA examinations were acquired at one week, one year, and two years postoperatively and at final follow-up. Weight-bearing RSA examinations were also undertaken with the operated lower limb in neutral and in maximum internal rotation positions. Maximum total point motion (MTPM) was calculated for the longitudinal and inducible displacement examinations (supine versus standing, standing versus internal rotation, and supine versus standing with internal rotation). All patients showed some inducible displacement. Two patients with radiolucent lines had greater mean standing-supine MTPM displacement (1.35; sd 0.38) compared with the remaining patients (0.68; sd 0.36). These two patients also had a greater mean longitudinal MTPM at ten years (0.64; sd 0.50) compared with the remaining patients (0.39; sd 0.13 mm). Small inducible displacements in well-fixed cemented tibial components were seen ten years postoperatively, of a similar magnitude to that which has been reported for well-fixed components one to two years postoperatively. Greater displacements were found in components with radiolucent lines. Cite this article: Bone Joint J 2018;100-B:170-5. ©2018 The British Editorial Society of Bone & Joint Surgery.

Measurement of parity nonconservation in the proton-proton total cross section at 800 MeV

International Nuclear Information System (INIS)

Bowman, J.D.

1986-01-01

A report is made of a measurement of parity nonconservation in the transmission of 800-MeV longitudinally polarized protons through an unpolarized, 1-m liquid-hydrogen target. The dependence of transmission on beam properties was studied to measure and to correct for systematic errors. The measured longitudinal asymmetry in the total cross section is A/sub L/ = [+2.4 +- 1.1 (statistical) +- 0.1 (systematic)] x 10 -7 . 25 refs., 2 figs

Longitudinal Analysis of Academic Burnout in Korean Middle School Students.

Science.gov (United States)

Kim, Boyoung; Lee, Minyoung; Kim, Keunhwa; Choi, Hyunju; Lee, Sang Min

2015-10-01

The purpose of the study was to investigate the longitudinal relationships between the initial values and slopes of three dimensions of burnout syndrome (i.e. emotional exhaustion, cynicism and academic inefficacy). The study utilized four-wave longitudinal data from a total of 367 (81.6% response rate) middle school students in South Korea. Comprising a 6-month interval survey, the first survey was conducted in June 2010, the second in December 2010, the third in June 2011 and the fourth in December 2011. All participants were 13-year-olds at the first and second surveys, and 14-year-olds at the third and fourth surveys. The Maslach Burnout Inventory-Student Survey was used for each survey to assess the level of academic burnout. The longitudinal data were analysed using latent growth modelling. The results of the study indicated that high initial values (intercept) for emotional exhaustion were associated with a higher rate of increase (slope) in cynicism and academic inefficacy. On the other hand, high initial values for cynicism and academic inefficacy were associated with a lower rate of increase in the other dimensions. This longitudinal study should promote understanding of burned-out students and contribute to the literature by informing the design of prevention programmes for academic burnout. Copyright © 2014 John Wiley & Sons, Ltd.

Total, Direct, and Indirect Effects in Logit Models

DEFF Research Database (Denmark)

Karlson, Kristian Bernt; Holm, Anders; Breen, Richard

It has long been believed that the decomposition of the total effect of one variable on another into direct and indirect effects, while feasible in linear models, is not possible in non-linear probability models such as the logit and probit. In this paper we present a new and simple method...... average partial effects, as defined by Wooldridge (2002). We present the method graphically and illustrate it using the National Educational Longitudinal Study of 1988...

Nontraumatic tibial polyethylene insert cone fracture in mobile-bearing posterior-stabilized total knee arthroplasty

Directory of Open Access Journals (Sweden)

Yohei Tanikake

2016-12-01

Full Text Available A 72-year-old male patient underwent mobile-bearing posterior-stabilized total knee arthroplasty for osteoarthritis. He experienced a nontraumatic polyethylene tibial insert cone fracture 27 months after surgery. Scanning electron microscopy of the fracture surface of the tibial insert cone suggested progress of ductile breaking from the posterior toward the anterior of the cone due to repeated longitudinal bending stress, leading to fatigue breaking at the anterior side of the cone, followed by the tibial insert cone fracture at the anterior side of the cone, resulting in fracture at the base of the cone. This analysis shows the risk of tibial insert cone fracture due to longitudinal stress in mobile-bearing posterior-stabilized total knee arthroplasty in which an insert is designed to highly conform to the femoral component.

Effects of Maternal Parenting and Mother-Child Relationship Quality on Short-Term Longitudinal Change in Self-Regulation in Early Adolescence

Science.gov (United States)

Moilanen, Kristin L.; Rambo-Hernandez, Karen E.

2017-01-01

The purpose of the present study was to explore the degree to which short-term longitudinal change in adolescent self-regulation was attributable to maternal parenting and mother-child relationship quality. A total of 821 mother-adolescent dyads provided data in the 1992 and 1994 waves of the Children of the National Longitudinal Survey of…

Effect of prestress force on longitudinal vibration of bonded tendons embedded in a nuclear containment

Energy Technology Data Exchange (ETDEWEB)

Kim, Byeong Hwa, E-mail: bhkim@kyungnam.ac.k [Dept. of Civil Engineering, Kyungnam University, 449 Wolyoung, Masan, Kyungnam 631-701 (Korea, Republic of); Jang, Jung Bum, E-mail: jbjang@kepri.re.k [Nuclear Power Laboratory, Korea Electric Power Research Institute, 103-16 Munji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of); Lee, Hong Pyo, E-mail: hplee@kepri.re.k [Nuclear Power Laboratory, Korea Electric Power Research Institute, 103-16 Munji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of); Lee, Do Hyung, E-mail: dohlee@pcu.ac.k [Dept. of Civil Environmental and Railroad Engineering, Paichai University, Yonja 1 gil (439-6 Doma 2 dong), Seo-gu, Daejeon 302-735 (Korea, Republic of)

2010-06-15

In this paper, evaluation of tensile force on bonded seven-wire strand embedded in nuclear reactor containments has been nondestructively investigated. For this purpose, a total of eight prestressed concrete beam specimens with different tension force levels have been fabricated and tested in terms of using an impact pulse at one end of the strand. Subsequently, various longitudinal vibration characteristics excited by the pulse have been analyzed in detailed. In short, the present study has demonstrated that longitudinal frequency, elastic wave velocity, and elastic modulus are nonlinearly increased as the tensile force level is increased. It is thus postulated that the longitudinal vibration characteristics of the existing bonded tendons can be of promising indicators for the inspection of a tensile force loss.

Regional Longitudinal Myocardial Deformation Provides Incremental Prognostic Information in Patients with ST-Segment Elevation Myocardial Infarction

DEFF Research Database (Denmark)

Biering-Sorensen, Tor; Jensen, Jan Skov; Pedersen, Sune H

2016-01-01

deformation in comparison to GLS, conventional echocardiography and clinical information. Method In total 391 patients were admitted with ST-Segment elevation myocardial infarction (STEMI), treated with primary percutaneous coronary intervention and subsequently examined by echocardiography. All patients were...... information to clinical and conventional echocardiographic information (Harrell's c-statistics: 0.63 vs. 0.67, p = 0.032). In addition, impaired longitudinal deformation outside the culprit lesion perfusion region was significantly associated with an adverse outcome (p...). Conclusion Regional longitudinal myocardial deformation measures, regardless if determined by TDI or 2DSE, are superior prognosticators to GLS. In addition, impaired longitudinal deformation in the inferior myocardial segment provides prognostic information over and above clinical and conventional...

The longitudinal trajectory of post-surgical % total weight loss among middle-aged women who had undergone bariatric surgery

Directory of Open Access Journals (Sweden)

Dong-Chul Seo

2017-03-01

Full Text Available Middle-aged women are at a higher risk of being obese. We examined the trajectory of post-surgical % total weight loss (%TWL among middle-aged female bariatric patients. We fitted sequential generalized estimating equations models to analyze a sample of women who received bariatric surgery in 1995–2012, aged 40–65 years at the time of surgery (N = 158,292 whose pre-operative body mass index (BMI was ≥30 kg/m2 in the Bariatric Outcomes Longitudinal Database. The %TWL computed by 100% × (pre-surgery BMI − post-surgery BMI / pre-surgery BMI showed different trajectories depending on type of surgery. For gastric banding, %TWL increased rapidly right after bariatric surgery and started to decrease around 1 year after surgery. For Roux-en-Y gastric bypass (RYGB and sleeve gastrectomy, %TWL overall did not show remarkable changes from around 1 year after surgery. The highest increase in %TWL was observed in patients whose pre-operative BMI was 40 or higher and those who had undergone RYGB (ps < 0.001. Whereas the trajectories of %TWL among patients with sleeve gastrectomy and gastric banding did not differ much between different pre-operative BMI groups, the trajectories for RYGB were notably different between different pre-operative BMI groups (ps < 0.001. Middle-aged female bariatric patients are likely to achieve the highest %TWL if they receive RYGB and if their pre-operative BMI is 40 or higher. Further research is warranted to corroborate the present study's finding on the long-term effect of different types of bariatric surgery on %TWL among middle-aged women.

A study of the HEB longitudinal dynamics

International Nuclear Information System (INIS)

Larson, D.J.

1993-12-01

A study of the High Energy Booster (HEB) longitudinal dynamics is presented. Full derivations of ramp dependent longitudinal variables are given. The formulas assume that the input magnetic field and beam longitudinal emittance are known as a function of time, and that either the rf voltage or the rf bucket area are known as a function of time. Once these three inputs are specified, the formulas can be used to calculate values for all other longitudinal dynamics variables. The formulas have been incorporated into a single computer code named ELVIRA: Evaluation of Longitudinal Variables in Relativistic Accelerators. The ELVIRA code is documented here in detail. The ELVIRA code is used under two initial longitudinal emittance assumptions to plot ramp functions for the longitudinal dynamics design of the HEB as of May 5, 1992

Approaching maximal performance of longitudinal beam compression in induction accelerator drivers

International Nuclear Information System (INIS)

Mark, J.W.K.; Ho, D.D.M.; Brandon, S.T.; Chang, C.L.; Drobot, A.T.; Faltens, A.; Lee, E.P.; Krafft, G.A.

1986-01-01

Longitudinal beam compression occurs before final focus and fusion chamber beam transport and is a key process determining initial conditions for final focus hardware. Determining the limits for maximal performance of key accelerator components is an essential element of the effort to reduce driver costs. Studies directed towards defining the limits of final beam compression including considerations such as maximal available compression, effects of longitudinal dispersion and beam emittance, combining pulse-shaping with beam compression to reduce the total number of beam manipulators, etc., are given. Several possible techniques are illustrated for utilizing the beam compression process to provide the pulse shapes required by a number of targets. Without such capabilities to shape the pulse, an additional factor of two or so of beam energy would be required by the targets

Diet assessment in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil: Development of a food frequency questionnaire

Directory of Open Access Journals (Sweden)

Maria del Carmen Bisi Molina

2013-04-01

Full Text Available OBJECTIVE: The objective of this article is to present the development of the Food Frequency Questionaire used in the Longitudinal Study of Adult Health-Brazil and analyze how diet exposes individuals to cardiovascular diseases and type 2 diabetes Mellitus. METHODS: The Longitudinal Study of Adult Health-Brazil dietary assessment instrument is based on a previously validated Food Frequency Questionaire and the final list of items took into consideration a study done in the six Longitudinal Study of Adult Health-Brazil investigation centers. RESULTS: New foods/preparations were included in the Food Frequency Questionaire with their respective portions, totaling 114 items. The perspectives of dietary analysis and cardiovascular diseases and diabetes are presented in Longitudinal Study of Adult Health-Brazil. CONCLUSION: A new instrument was developed to cover the regional particularities of the study population.

Longitudinal relations between adolescents' self-esteem and prosocial behavior toward strangers, friends and family.

Science.gov (United States)

Fu, Xinyuan; Padilla-Walker, Laura M; Brown, Michael N

2017-06-01

The present study examined age-trends and longitudinal bidirectional relations in self-esteem and prosocial behavior toward strangers, friends, and family over a four-year time period (age 11 to 14). A total of 681 adolescents were recruited in the United States (51% girls, 28% single parent families). A longitudinal panel model was conducted and the results showed that adolescent self-esteem was associated longitudinally with subsequent prosocial behavior toward strangers, and earlier prosocial behavior toward strangers promoted subsequent self-esteem. There were no such bidirectional relations between self-esteem and prosocial behavior toward friends and family. Findings also highlight the complexity of adolescent development of selfesteem and the multidimensional nature of prosocial behavior. Discussion focuses on understanding the dynamic interplay between adolescent selfesteem and prosocial behavior. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

On Longitudinal Spectral Coherence

DEFF Research Database (Denmark)

Kristensen, Leif

1979-01-01

It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

Simulation of longitudinal dynamics of a freight train operating through a car dumper

Science.gov (United States)

Kovalev, R.; Sakalo, A.; Yazykov, V.; Shamdani, A.; Bowey, R.; Wakeling, C.

2016-06-01

A heavy haul train and car dumper model was created to analyse train longitudinal dynamics during dumping. Influence of such factors as performance curve of draft gears, total free slack in couplers, operating mode of train positioner and braking of last two cars of train on the in-train forces was considered.

Longitudinal Research with Latent Variables

CERN Document Server

van Montfort, Kees; Satorra, Albert

2010-01-01

This book combines longitudinal research and latent variable research, i.e. it explains how longitudinal studies with objectives formulated in terms of latent variables should be carried out, with an emphasis on detailing how the methods are applied. Because longitudinal research with latent variables currently utilizes different approaches with different histories, different types of research questions, and different computer programs to perform the analysis, the book is divided into nine chapters. Starting from some background information about the specific approach, short history and the ma

Multiplate ionization total absorption spectrometer with a compressed gas

International Nuclear Information System (INIS)

Baskakov, V.I.; Dolgoshein, B.A.; Kantserov, V.A.

1978-01-01

The characteristics of a multiplate total absorption spectrometer working with the compressed xenon (up to 25 atm) containing up to 23 radiation lengths of matter are studied. The dependence of the spectrometer energy resolution on the detecting matter density, on the material and thickness of the absorber plates has been studied. The ability of the spectrometer with a tungsten absorber to select hadrons and electrons with P=6 GeV/c by total energy release and characteristics of the cascade longitudinal development has been also studied. The gas spectrometer as it is shown differs quite slightly from the similar spectrometer with liquid argon as for its time resolution it is much better

Measurement of the longitudinal cross-section using the direction of the thrust axis in hadronic events at LEP

CERN Document Server

Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; De Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Fabbri, F.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C.K.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

1998-01-01

In the process e+e- to hadrons, one of the effects of gluon emission is to modify the 1+cos(theta)**2 form of the angular distribution of the thrust axis, an effect which may be quantified by the longitudinal cross-section. Using the OPAL detector at LEP, we have determined the longitudinal to total cross-section ratio to be 0.0127+-0.0016+-0.0013 at the parton level, in good agreement with the expectation of QCD computed to Order(alpha_s**2) Comparisions at the hadron level with Monte Carlo models are presented. The dependence of the longitudinal cross-section on the value of thrust has also been studied, and provides a new test of QCD.

Longitudinal joint specifications and performance.

Science.gov (United States)

2012-08-01

Deterioration of longitudinal joints is widely recognized as one of the major factors contributing to failure of asphalt pavements. Finding : ways to improve the durability of longitudinal joints will lead to improved service lives and lower life cyc...

Modal description of longitudinal space-charge fields in pulse-driven free-electron devices

Directory of Open Access Journals (Sweden)

Yu. Lurie

2010-05-01

Full Text Available In pulsed-beam free-electron devices, longitudinal space-charge fields result in collective effects leading to an expansion of short electron bunches along their trajectory. This effect restricts an application of intense ultrashort electron pulses in free-electron radiation sources. A careful theoretical treatment is required in order to achieve an accurate description of the self-fields and the resulted electron beam dynamics. In this paper, longitudinal space-charge fields are considered in the framework of a three-dimensional, space-frequency approach. The model is based on the expansion of the total electromagnetic field (including self-fields in terms of transverse eigenmodes of the (cold cavity, in which the field is excited and propagates. The electromagnetic field, originally obtained in the model as a solution of the wave equation, is shown to satisfy also Gauss’s law. We applied the theory to derive an analytical expression for the longitudinal electric field of a pointlike charge, moving along a waveguide at a constant velocity. This enables consideration and study of the role played by different terms of the resulted expressions, such as components arising from forward and backward waves, propagating waves, and under cutoff frequencies, and so on. Possible simplifications in evaluation of longitudinal space-charge fields are discussed.

Evaluation of longitudinal loading of tank trains during motion in longitudinal changes of gradient

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S.V. Myamlin

2013-06-01

Full Text Available Purpose. To research the tank train longitudinal loading during motion by track sections with changes of gradient. The trains of different length that consist of bogie tank wagons should be examined. Influence of cargo type on longitudinal loading of train during motion in concave section of track should be evaluated. Methodology. The level of the largest longitudinal forces was estimated by mathematical simulation. It was assumed that change of gradient is formed by two grades with baffle platforms, length 50 meters, so that the algebraic difference of limiting grades vary from 10‰ to 40‰, pitch 10‰. The initial speeds were 40, 60, 80, 100, 120 km/h. For evaluation of the longitudinal loading the regulating braking and motion "by coasting" was considered. For evaluation of buffing loads the entry to the concave gradient change of expanded train is considered, and in order to determine the quasi-static forces the compressed train is considered. Findings. As a result of calculations the dependencies of maximal longitudinal forces in the trains on the cargo type, the algebraic difference of the grades, the number of tank wagons, the initial speed, motion modes, and initial gaps condition in the train were obtained. Originality. The longitudinal loading of freight cars of different length formed by the similar bogie tank wagons with one locomotive was obtained. The locomotive is placed in the train head during motion in concave track sections with various algebraic difference of the grades "on coasting" and during the regulating braking mode. The obtained results can be used for parameters standardization of profile elevation of the track. Practical value. The obtained results show that during operation of tank trains on track sections of complex breakage the most dangerous is regulating braking of preliminary compressed trains during entering on concave parts of track. Level of the greatest buffing and quasi-static longitudinal forces is

Regional Longitudinal Myocardial Deformation Provides Incremental Prognostic Information in Patients with ST-Segment Elevation Myocardial Infarction.

Directory of Open Access Journals (Sweden)

Tor Biering-Sørensen

Full Text Available Global longitudinal systolic strain (GLS has recently been demonstrated to be a superior prognosticator to conventional echocardiographic measures in patients after myocardial infarction (MI. The aim of this study was to evaluate the prognostic value of regional longitudinal myocardial deformation in comparison to GLS, conventional echocardiography and clinical information.In total 391 patients were admitted with ST-Segment elevation myocardial infarction (STEMI, treated with primary percutaneous coronary intervention and subsequently examined by echocardiography. All patients were examined by tissue Doppler imaging (TDI and two-dimensional strain echocardiography (2DSE.During a median-follow-up of 5.3 (IQR 2.5-6.1 years the primary endpoint (death, heart failure or a new MI was reached by 145 (38.9% patients. After adjustment for significant confounders (including conventional echocardiographic parameters and culprit lesion, reduced longitudinal performance in the anterior septal and inferior myocardial regions (but not GLS remained independent predictors of the combined outcome. Furthermore, inferior myocardial longitudinal deformation provided incremental prognostic information to clinical and conventional echocardiographic information (Harrell's c-statistics: 0.63 vs. 0.67, p = 0.032. In addition, impaired longitudinal deformation outside the culprit lesion perfusion region was significantly associated with an adverse outcome (p<0.05 for all deformation parameters.Regional longitudinal myocardial deformation measures, regardless if determined by TDI or 2DSE, are superior prognosticators to GLS. In addition, impaired longitudinal deformation in the inferior myocardial segment provides prognostic information over and above clinical and conventional echocardiographic risk factors. Furthermore, impaired longitudinal deformation outside the culprit lesion perfusion region seems to be a paramount marker of adverse outcome.

Prognostic factors for survival after salvage total laryngectomy following radiotherapy or chemoradiation failure

DEFF Research Database (Denmark)

Wulff, N B; Andersen, E; Kristensen, C A

2017-01-01

with higher N classification and need for lymph node excision during salvage total laryngectomy along with use of frozen sections. The high number of patients with recurrence within 1 year after salvage total laryngectomy occurred although thorough and regular follow-up visits were performed.......OBJECTIVE: The primary aims were to determine the rates of and prognostic factors for overall survival, disease-specific survival and disease-free survival following salvage total laryngectomy. DESIGN: Retrospective longitudinal study. SETTING: Tertiary medical centres. PARTICIPANTS: A total of 142...... survival, disease-specific survival and disease-free survival were 37.7%, 54.9% and 55.3%, respectively. N classification at primary diagnosis, lymph node excision and postoperative complications within 1 year after salvage total laryngectomy were prognostic factors for shorter overall survival, disease...

Spatial relationship of 1-meter equatorial spread-F irregularities and depletions in total electron content

International Nuclear Information System (INIS)

Tsunoda, R.T.; Towle, D.M.

1979-01-01

An experiment was conducted at Kwajalein Atoll, Marshall Islands to investigate the spatial relationship of 1-m equatorial spread-F irregularities to total electron content (TEC) depletions. A high-power radar was operated (1) in a backscatter scan mode to spatially map the distribution of 1-m irregularities, and (2) in a dual-frequency, satellite-track mode to obtain the longitudinal TEC variations. We show that radar backscatter ''plumes'' found in the disturbed, nighttime equatorial ionosphere are longitudinally coincident with TEC depletions. We suggest that the TEC depletions are probably due to the presence of plasma ''bubbles'' in the equatorial F layer

Longitudinal Associations between Adolescent Perceived Degree and Style of Parental Prohibition and Internalization and Defiance

Science.gov (United States)

Vansteenkiste, Maarten; Soenens, Bart; Van Petegem, Stijn; Duriez, Bart

2014-01-01

This study examined associations between perceived degree and style of parental prohibition and adolescents' internalization of and oppositional defiance against parental rules in the friendship and moral domain. Relations were investigated in 2 longitudinal adolescent samples (total N = 532). Results indicated that perceived style but not…

Longitudinal Space Charge in the SPS

CERN Document Server

Lasheen, Alexandre

2016-01-01

Longitudinal instabilities due to the SPS beam coupling impedance are a major issue for future projects and it is essential to have an accurate SPS impedance model to study them. The longitudinal space charge effect can be modelled by a pure reactive impedance and should also be included in simulations as it may have an impact at low energy. In this Note, the effect of the longitudinal space charge in the SPS is evaluated by taking into account the variation of the transverse beam size and vacuum chamber geometry along the ring. Scaling laws are used to investigate what are the most important parameters for the evaluation of the longitudinal space charge impedance.

Cross-Sectional Analysis of Longitudinal Mediation Processes.

Science.gov (United States)

O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio

2018-01-01

Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.

Total dynamic response of a PSS vehicle negotiating asymmetric road excitations

Science.gov (United States)

Zhu, Jian Jun; Khajepour, Amir; Esmailzadeh, Ebrahim

2012-12-01

A planar suspension system (PSS) is a novel automobile suspension system in which an individual spring-damper strut is implemented in both the vertical and longitudinal directions, respectively. The wheels in a vehicle with such a suspension system can move back and forth relative to the chassis. When a PSS vehicle experiences asymmetric road excitations, the relative longitudinal motion of wheels with respect to the chassis in two sides of the same axle are not identical, and thus the two wheels at one axle will not be aligned in the same axis. The total dynamic responses, including those of the bounce, pitch and the roll of the PSS vehicle, to the asymmetric road excitation may exhibit different characteristics from those of a conventional vehicle. This paper presents an investigation into the comprehensive dynamic behaviour of a vehicle with the PSS, in such a road condition, on both the straight and curved roads. The study was carried out using an 18 DOF full-car model incorporating a radial-spring tyre-ground contact model and a 2D tyre-ground dynamic friction model. Results demonstrate that the total dynamic behaviour of a PSS vehicle is generally comparable with that of the conventional vehicle, while PSS exhibits significant improvement in absorbing the impact forces along the longitudinal direction when compared to the conventional suspension system. The PSS vehicle is found to be more stable than the conventional vehicle in terms of the directional performance against the disturbance of the road potholes on a straight line manoeuvre, while exhibiting a very similar handling performance on a curved line.

The association between modifiable well-being risks and productivity: a longitudinal study in pooled employer sample.

Science.gov (United States)

Shi, Yuyan; Sears, Lindsay E; Coberley, Carter R; Pope, James E

2013-04-01

To examine the longitudinal relationship between modifiable well-being risks and productivity. A total of 19,121 employees from five employers participated in baseline and follow-up well-being assessment surveys. Multivariate regressions assessed whether changes in absenteeism, presenteeism, and job performance were associated with changes in 19 modifiable well-being risks. Over time, a 5% reduction in total count of well-being risks was significantly associated with 0.74% decrease in absenteeism, 2.38% decrease in presenteeism, and 0.24% increase in performance. High blood pressure, recurring pain, unhealthy diet, inadequate exercise, poor emotional health, poor supervisor relationship, not utilizing strengths doing job, and organization unsupportive of well-being had greater independent contributions in explaining productivity impairment. The often-ignored well-being risks such as work-related and financial health risks provided incremental explanation of longitudinal productivity variations beyond traditional measures of health-related risks.

Presymptomatic and longitudinal neuroimaging in neurodegeneration--from snapshots to motion picture: a systematic review.

Science.gov (United States)

Schuster, Christina; Elamin, Marwa; Hardiman, Orla; Bede, Peter

2015-10-01

Recent quantitative neuroimaging studies have been successful in capturing phenotype and genotype-specific changes in dementia syndromes, amyotrophic lateral sclerosis, Parkinson's disease and other neurodegenerative conditions. However, the majority of imaging studies are cross-sectional, despite the obvious superiority of longitudinal study designs in characterising disease trajectories, response to therapy, progression rates and evaluating the presymptomatic phase of neurodegenerative conditions. The aim of this work is to perform a systematic review of longitudinal imaging initiatives in neurodegeneration focusing on methodology, optimal statistical models, follow-up intervals, attrition rates, primary study outcomes and presymptomatic studies. Longitudinal imaging studies were identified from 'PubMed' and reviewed from 1990 to 2014. The search terms 'longitudinal', 'MRI', 'presymptomatic' and 'imaging' were utilised in combination with one of the following degenerative conditions; Alzheimer's disease, amyotrophic lateral sclerosis/motor neuron disease, frontotemporal dementia, Huntington's disease, multiple sclerosis, Parkinson's disease, ataxia, HIV, alcohol abuse/dependence. A total of 423 longitudinal imaging papers and 103 genotype-based presymptomatic studies were identified and systematically reviewed. Imaging techniques, follow-up intervals and attrition rates showed significant variation depending on the primary diagnosis. Commonly used statistical models included analysis of annualised percentage change, mixed and random effect models, and non-linear cumulative models with acceleration-deceleration components. Although longitudinal imaging studies have the potential to provide crucial insights into the presymptomatic phase and natural trajectory of neurodegenerative processes a standardised design is required to enable meaningful data interpretation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under

Sleep-wake profiles predict longitudinal changes in manic symptoms and memory in young people with mood disorders.

Science.gov (United States)

Robillard, Rébecca; Hermens, Daniel F; Lee, Rico S C; Jones, Andrew; Carpenter, Joanne S; White, Django; Naismith, Sharon L; Southan, James; Whitwell, Bradley; Scott, Elizabeth M; Hickie, Ian B

2016-10-01

Mood disorders are characterized by disabling symptoms and cognitive difficulties which may vary in intensity throughout the course of the illness. Sleep-wake cycles and circadian rhythms influence emotional regulation and cognitive functions. However, the relationships between the sleep-wake disturbances experienced commonly by people with mood disorders and the longitudinal changes in their clinical and cognitive profile are not well characterized. This study investigated associations between initial sleep-wake patterns and longitudinal changes in mood symptoms and cognitive functions in 50 young people (aged 13-33 years) with depression or bipolar disorder. Data were based on actigraphy monitoring conducted over approximately 2 weeks and clinical and neuropsychological assessment. As part of a longitudinal cohort study, these assessments were repeated after a mean follow-up interval of 18.9 months. No significant differences in longitudinal clinical changes were found between the participants with depression and those with bipolar disorder. Lower sleep efficiency was predictive of longitudinal worsening in manic symptoms (P = 0.007). Shorter total sleep time (P = 0.043) and poorer circadian rhythmicity (P = 0.045) were predictive of worsening in verbal memory. These findings suggest that some sleep-wake and circadian disturbances in young people with mood disorders may be associated with less favourable longitudinal outcomes, notably for subsequent manic symptoms and memory difficulties. © 2016 European Sleep Research Society.

Narrow intra-individual variation of maternal thyroid function in pregnancy based on a longitudinal study on 132 women

DEFF Research Database (Denmark)

Boas, M.; Forman, Julie Lyng; Juul, A.

2009-01-01

BACKGROUND: Adaptive alterations in maternal physiology cause changes in thyroid hormone levels throughout pregnancy, and precise biochemical evaluation is thus highly dependent on gestation-specific reference intervals and expected intra-individual variation. OBJECTIVE: The aim of the study...... was the assessment of the intra-individual variation as well as the longitudinal course of thyroid hormones during normal pregnancy and factors that influence the normal reference range for thyroid function. For this purpose, a longitudinal statistical model was applied. DESIGN: In a cohort of 132 pregnant women......, serial blood samples were obtained and ultrasound scans were performed throughout pregnancy. METHODS: Serum levels of TSH, free and total thyroxine (T(4)), free and total triiodothyronine (T(3)) as well as autoantibodies against thyroid peroxidase and thyroglobulin were measured in 979 serum samples...

The Tokyo Oldest Old Survey on Total Health (TOOTH: A longitudinal cohort study of multidimensional components of health and well-being

Directory of Open Access Journals (Sweden)

Gondo Yasuyuki

2010-06-01

Full Text Available Abstract Background With the rapid worldwide increase in the oldest old population, considerable concern has arisen about the social and economic burden of diseases and disability in this age group. Understanding of multidimensional structure of health and its life-course trajectory is an essential prerequisite for effective health care delivery. Therefore, we organized an interdisciplinary research team consisting of geriatricians, dentists, psychologists, sociologists, and epidemiologists to conduct a longitudinal observational study. Methods/Design For the Tokyo Oldest Old Survey on Total Health (TOOTH study, a random sample of inhabitants of the city of Tokyo, aged 85 years or older, was drawn from the basic city registry. The baseline comprehensive assessment consists of an in-home interview, a self-administered questionnaire, and a medical/dental examination. To perform a wide variety of biomedical measurements, including carotid ultrasonography and a detailed dental examination, participants were invited to our study center at Keio University Hospital. For those who were not able to visit the study center, we provided the option of a home-based examination, in which participants were simultaneously visited by a geriatrician and a dentist. Of 2875 eligible individuals, a total of 1152 people were recruited, of which 542 completed both the in-home interview and the medical/dental examination, with 442 completed the in-home interview only, and another 168 completed self or proxy-administered data collection only. Carotid ultrasonography was completed in 458 subjects, which was 99.6% of the clinic visitors (n = 460. Masticatory assessment using a colour-changeable chewing gum was completed in 421 subjects, a 91.5% of the clinic visitors. Discussion Our results demonstrated the feasibility of a new comprehensive study that incorporated non-invasive measurements of subclinical diseases and a detailed dental examination aiming at community

Longitudinal processes in Salto Grande reservoir (Americana, SP, Brazil and its influence in the formation of compartment system

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L. H. ZANATA

Full Text Available Studies on the longitudinal processes in reservoirs, involving physical, chemical and biological processes have been thoroughly appraised, suggesting the existence of a longitudinal organization controlled by the entrance and circulation of water which inserts modifications in the structuring of the system. To evaluate this effect, the Salto Grande reservoir (Americana, SP was analyzed in 11 sampling stations in its longitudinal axis, in the rainy and dry seasons of 1997 considering the physical chemical and biological variables. Analyzing the results in agreement with the declining concentration degree of the river--barrage direction, a more significant correlation was verified in the dry period for total phosphorus (r² = 0.86, dissolved total phosphate (r² = 0.83, nitrite (r² = 0.93, inorganic phosphate (r² = 0.89, ammonium (r² = 0.84 and suspended material (r² = 0.85. In the rainy period, only nitrite (r² = 0.90 and conductivity (r² = 0.89 presented correlation with the distance of the dam, which demonstrates the effects of precipitation and the operational mechanism of the dam, as well as the distinction among the physical (sedimentation, chemical (oxidation and biological (decomposition processes in spatial heterogeneity of the system. These factors were decisive in the organization of these communities, with higher occurrence of rotifers and copepods in relation to cladocerans, the first ones being more abundant in the entrance of the Atibaia river, decreasing towards the dam direction, while copepods presented an inverse pattern. A distribution pattern similar to Copepoda was also verified for the Cladocera, evidencing a tendency to increase the density of organisms in the stations distant to the entrance of the Atibaia river, not being registered, however, a distribution gradient in the longitudinal axis, as observed for rotifers and copepods. In relation to the trophic degree a longitudinal gradient was also verified from

Longitudinal dynamics of laser-cooled fast ion beams

DEFF Research Database (Denmark)

Weidemüller, M.; Eike, B.; Eisenbarth, U.

1999-01-01

We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal-transverse co......We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal....... When applying laser cooling in square-well buckets over long time intervals, hard Coulomb collisions suddenly disappear and the longitudinal temperature drops by about a factor of three. The observed longitudinal behaviour of the beam shows strong resemblance with the transition to an Coulomb...

Longitudinal beam dynamics at transition crossing

Energy Technology Data Exchange (ETDEWEB)

Bogacz, S.A.

1991-11-01

A brief outline of the longitudinal single particle dynamics at transition is presented in terms of phase-space mappings. Simple quantitative prediction about the phase-space dilution is made. More realistic simulation (ESME) of the transition crossing is carried out (including various collective and single particle effects contributing to the longitudinal emittance blow up). The simulation takes into account the longitudinal space-charge force (bunch length oscillation), the transverse space-charge (the Umstaetter effect) and finally the dispersion of the momentum compaction factor (the Johnsen effect). As a result of this simulation one can separate relative strengths of the above mechanisms and study their individual effects on the longitudinal phase-space evolution, especially filamentation of the bunch and formation of a galaxy-like'' pattern. 7 refs., 2 figs.

Loading Conditions and Longitudinal Strength

DEFF Research Database (Denmark)

Sørensen, Herman

1995-01-01

Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength.......Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength....

A measurement of ΔσL(np), the difference between neutron-proton total cross sections in pure longitudinal spin states

International Nuclear Information System (INIS)

Beddo, M.E.

1990-10-01

A measurement off Δσ L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD 2 ). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0 degree. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a ''beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD 2 target. The experimental values of Δσ L (np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from Δσ L (np) using existing pp data (I = 1), with the unexpected result that Δσ L (I = 0) was found to be essentially identical in shape to Δσ L (I = 1). The significance of this is not yet understood

Fetal and infant growth patterns associated with total and abdominal fat distribution in school-age children

NARCIS (Netherlands)

Gishti, O.; Gaillard, R.; Manniesing, R.; Abrahamse-Berkeveld, M.; Beek, E.M. van der; Heppe, D.H.M.; Steegers, E.A.P.; Hofman, A.; Duijts, L.; Durmus, B.u.; Jaddoe, V.W.

2014-01-01

Context: Higher infant growth rates are associated with an increased risk of obesity in later life. Objective: We examined the associations of longitudinally measured fetal and infant growth patterns with total and abdominal fat distribution in childhood. Design, Settings and participants:We

Impact of Total Vending Machine Restrictions on US Young Adult Smoking

Science.gov (United States)

Kelly, Brian C.; Kadowaki, Joy

2016-01-01

Introduction: In an analysis of smoking using a longitudinal sample of US young adults, we extend research on tobacco vending machine restrictions beyond its prior focus on minors by examining the influence of total vending machine restrictions, which apply to adult-only facilities and represents the only remaining vending machine exemption since the enactment of the Family Smoking Prevention and Tobacco Control Act. We identify whether the passage of a restriction influences an individual’s smoking on repeated observations, and if the propensity is lower among those who live in locations with a restriction. Methods: Combining a repository of US tobacco policies at all geographic levels with the nationally-representative geocoded National Longitudinal Survey of Youth 1997 and Census data, we use multilevel logistic regression to examine the impact of total vending machine restrictions on any past 30-day smoking and past 30-day smoking of one pack per day among young adults (ages 19–31), while accounting for other tobacco control policy, community, and individual covariates. Results: We find that total vending machine restrictions decrease any recent smoking (OR = 0.451; p vending machine restrictions on smoking a pack daily. Conclusions: Total vending machine restrictions appear to be an effective, yet highly underutilized, means of tobacco control. Implications: Past scientific inquiries examining vending machine restrictions have focused upon minor access, adolescent perceptions of availability, and subsequent smoking. The potential for total vending machine restrictions, which extend to adult-only facilities, to influence patterns of smoking among those of legal age, remains significant. Those who are subject to total vending machine restrictions for longer periods are less likely to have recently smoked, but individuals do not change their smoking behavior in response to the passage of a restriction. These restrictions do not affect heavy smokers. Such

The lowest order total electromagnetic correction to the deep inelastic scattering of polarized leptons on polarized nucleons

International Nuclear Information System (INIS)

Shumeiko, N.M.; Timoshin, S.I.

1991-01-01

Compact formulae for a total 1-loop electromagnetic corrections, including the contribution of electromagnetic hadron effects to the deep inelastic scattering of polarized leptons on polarized nucleons in the quark-parton model have been obtained. The cases of longitudinal and transverse nucleon polarization are considered in detail. A thorough numerical calculation of corrections to cross sections and polarization asymmetries at muon (electron) energies over the range of 200-2000 GeV (10-16 GeV) has been made. It has been established that the contribution of corrections to the hadron current considerably affects the behaviour of longitudinal asymmetry. A satisfactory agreement is found between the model calculations of corrections to the lepton current and the phenomenological calculation results, which makes it possible to find the total 1-loop correction within the framework of a common approach. (Author)

Longitudinal research and data collection in primary care.

NARCIS (Netherlands)

Weel, C. van

2005-01-01

PURPOSE: This article reviews examples of and experience with longitudinal research in family medicine. The objective is to use this empirical information to formulate recommendations for improving longitudinal research. METHODS: The article discusses 3 longitudinal studies from the Nijmegen

Prevenção de aderências pericárdicas pós-operatórias com uso de carboximetilquitosana termoestéril Prevention of postoperative pericardial adhesions using thermal sterile carboxymethyl chitosan

Directory of Open Access Journals (Sweden)

Luiz Renato Dias Daroz

2008-12-01

Full Text Available OBJETIVO: Este trabalho tem como objetivo avaliar alterações físico-químicas da carboximetilquitosana após termoesterilização e sua eficácia na prevenção de aderências pericárdicas pós-esternotomia. MÉTODOS: Após ser submetida a termoesterilização em autoclave, a carboximetilquitosana termoestéril (CMQte foi submetida a análises físico-químicas. Doze animais foram divididos em dois grupos e submetidos à pericardiotomia e a protocolo de indução de aderências. A seguir, foi aplicada de forma tópica a CMQte ou solução salina. Após 8 semanas, foi realizada esternotomia e avaliação macroscópica do grau de aderências, tempo de dissecção e quantidade do uso de dissecção cruenta e avaliação microscópica. RESULTADOS: As análises físico-químicas não mostraram diferença entre a CMQ e CMQte. A avaliação macroscópica mostrou que a intensidade das aderências foi significantemente menor no grupo CMQte (P=0,007. O tempo de dissecção e o uso de dissecção cruenta também apresentaram reduções significativas (P=0,007, P=0,008; respectivamente. CONCLUSÃO: O método de esterilização empregado não alterou as propriedades físico-químicas da carboximetilquitosana. O uso de biopolímeros de barreira como a CMQte pode reduzir a intensidade das aderências pós-cirúrgicas no pericárdio, diminuindo as complicações da esternotomia em reoperações cardiovasculares.OBJECTIVE: The aim of this study is to evaluate CMC physical-chemical alterations after thermal sterilization and its efficacy in preventing poststernotomy pericardial adhesions. METHODS: After autoclaving thermal sterilization, thermal sterile Carboxymethyl Chitosan (CMCts was submitted to physical-chemical analysis. Twelve animals were divided into two groups and underwent pericardiotomy and adhesion induction protocol. Afterward, topic CMCts or saline solution was administered. After 8 weeks, a sternotomy was performed for adhesion score

Reanalysis of morphine consumption from two randomized controlled trials of gabapentin using longitudinal statistical methods

Directory of Open Access Journals (Sweden)

Zhang S

2015-02-01

Full Text Available Shiyuan Zhang,1 James Paul,2 Manyat Nantha-Aree,2 Norman Buckley,2 Uswa Shahzad,2 Ji Cheng,2 Justin DeBeer,5 Mitchell Winemaker,5 David Wismer,5 Dinshaw Punthakee,5 Victoria Avram,5 Lehana Thabane1–4 1Department of Clinical Epidemiology and Biostatistics, McMaster University, 2Department of Anesthesia, McMaster University, 3Biostatistics Unit/Centre for Evaluation of Medicines, St Joseph’s Healthcare-Hamilton, 4Population Health Research Institute, Hamilton Health Science/McMaster University, 5Department of Surgery, Division of Orthopaedics, McMaster University, Hamilton, ON, Canada Background: Postoperative pain management in total joint replacement surgery remains ineffective in up to 50% of patients and has an overwhelming impact in terms of patient well-being and health care burden. We present here an empirical analysis of two randomized controlled trials assessing whether addition of gabapentin to a multimodal perioperative analgesia regimen can reduce morphine consumption or improve analgesia for patients following total joint arthroplasty (the MOBILE trials. Methods: Morphine consumption, measured for four time periods in patients undergoing total hip or total knee arthroplasty, was analyzed using a linear mixed-effects model to provide a longitudinal estimate of the treatment effect. Repeated-measures analysis of variance and generalized estimating equations were used in a sensitivity analysis to compare the robustness of the methods. Results: There was no statistically significant difference in morphine consumption between the treatment group and a control group (mean effect size estimate 1.0, 95% confidence interval −4.7, 6.7, P=0.73. The results remained robust across different longitudinal methods. Conclusion: The results of the current reanalysis of morphine consumption align with those of the MOBILE trials. Gabapentin did not significantly reduce morphine consumption in patients undergoing major replacement surgeries. The

Which emotional regulatory strategy makes Chinese adolescents happier? A longitudinal study.

Science.gov (United States)

Sang, Biao; Deng, Xinmei; Luan, Ziyan

2014-12-01

Growing interest in emotion regulation is reflected in the studies of cognitive and social development. However, the extant studies mainly highlight how emotion regulation develops based on a western value system. This study utilised a longitudinal design to examine the development of emotion regulation and explored the contributions of different regulatory strategies to emotion experience regarding the early adolescent development period in a Chinese population. A total of 303 Chinese adolescents (age range = 10-14 years) were followed up in a three-phase longitudinal study for 3 years. In each phase of the study, participants completed Adolescents Emotion Regulation Questionnaire and Daily Emotion Scale. Results of hierarchical linear regressions revealed that Chinese adolescents reported more down-regulation. Down-regulation is more effective than up-regulation in enhancing desirable emotion experience and reducing undesirable emotion experience during adolescents' development. Also, the adaptive functions of emotional regulatory strategies in Chinese background were discussed. © 2014 International Union of Psychological Science.

Longitudinal trends in gasoline price and physical activity: The CARDIA study

Science.gov (United States)

Hou, Ningqi; Popkin, Barry M; Jacobs, David R; Song, Yan; Guilkey, David K; He, Ka; Lewis, Cora E.; Gordon-Larsen, Penny

2011-01-01

Objective To investigate longitudinal associations between community-level gasoline price and physical activity (PA). Method In the Coronary Artery Risk Development in Young Adults study, 5,115 black and white participants aged 18–30 at baseline 1985–86 were recruited from four U.S. cities (Birmingham, Chicago, Minneapolis and Oakland) and followed over time. We used data from 3 follow-up exams: 1992–93, 1995–96, and 2000–01, when the participants were located across 48 states. From questionnaire data, a total PA score was summarized in exercise units (EU) based on intensity and frequency of 13 PA categories. Using Geographic Information Systems, participants’ residential locations were linked to county-level inflation-adjusted gasoline price data collected by the Council for Community & Economic Research. We used a random-effect longitudinal regression model to examine associations between time-varying gasoline price and time-varying PA, controlling for age, race, gender, baseline study center, and time-varying education, marital status, household income, county cost of living, county bus fare, census block-group poverty, and urbanicity. Results Holding all control variables constant, a 25-cent increase in inflation-adjusted gasoline price was significantly associated with an increase of 9.9 EU in total PA (95%CI: 0.8–19.1). Conclusion Rising prices of gasoline may be associated with an unintended increase in leisure PA. PMID:21338621

Tangential Biopsy Thickness versus Lesion Depth in Longitudinal Melanonychia: A Pilot Study

Directory of Open Access Journals (Sweden)

Nilton Di Chiacchio

2012-01-01

Full Text Available Longitudinal melanonychia can be caused by melanocyte activation (hypermelanosis or proliferation (lentigo, nevus or melanoma. Histopathologic examination is mandatory for suspicious cases of melanomas. Tangential biopsy of the matrix is an elegant technique avoiding nail plate dystrophy, but it was unknown whether the depth of the sample obtained by this method is adequate for histopathologic diagnosis. Twenty-two patients with longitudinal melanonychia striata were submitted to tangential matrix biopsies described by Haneke. The tissue was stained with hematoxylin-eosin and the specimens were measured at 3 distinct points according to the total thickness: largest (A, intermediate (B and narrowest (C then divided into 4 groups according to the histopathologic diagnosis (G1: hypermelanosis; G2: lentigos; G3: nevus; G4: melanoma. The lesions were measured using the same method. The mean specimen/lesion thickness measure values for each group was: G1: 0,59/0,10 mm, G2: 0,67/0,08 mm, G3: 0,52/0,05 mm, G4: 0,58/0,10 mm. The general average thickness for all the specimens/lesions was 0,59/0,08 mm. We concluded that the tangential excision, for longitudinal melanonychia, provides an adequate material for histopathological diagnosis.

Longitudinal associations between maternal feeding and overweight in low-income toddlers.

Science.gov (United States)

Lumeng, Julie C; Kaciroti, Niko; Retzloff, Lauren; Rosenblum, Katherine; Miller, Alison L

2017-06-01

Maternal feeding is a frequent intervention target for the prevention of early childhood obesity but longitudinal associations between feeding and child overweight are poorly understood. This observational cohort study sought to examine the cross-lagged associations between maternal feeding and overweight across ages 21, 27, and 33 months. Feeding was measured by maternal self-report (n = 222) at each age. Child weight and length were measured. Cross-lagged analysis was used to evaluate longitudinal associations between feeding and overweight, adjusting for infant birth weight, maternal body mass index, maternal education, and maternal depressive symptoms. The sample was 50.5% white, 52.3% male and 37.8% of mothers had a high school education or less. A total of 30.6%, 29.2%, and 26.3% of the sample was overweight at each age, respectively. Pressuring to Finish, Restrictive with regard to Amount, Restrictive with regard to Diet Quality, Laissez-Faire with regard to Diet Quality, Responsiveness to Satiety, Indulgent Permissive, Indulgent Coaxing, Indulgent Soothing, and Indulgent Pampering each tracked strongly across toddlerhood. There were no significant associations between maternal feeding and child overweight either in cross-sectional or cross-lagged associations. Our results do not support a strong causal role for feeding in childhood overweight. Future work longitudinal work should consider alternative approaches to conceptualizing feeding and alternative measurement approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

46 CFR 154.176 - Longitudinal contiguous hull structure.

Science.gov (United States)

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 the...

The calculated longitudinal impedance of the SLC [Stanford Linear Collider] damping rings

International Nuclear Information System (INIS)

Bane, K.L.F.

1988-05-01

A high level of current dependent bunch lengthening has been observed in the north damping ring of the Stanford Linear Collider (SLC), indicating that the ring's impedance is very inductive. This level of bunch lengthening will limit the performance of the SLC. In order to study the problem of bunch lengthening in the damping ring and the possibility of reducing their inductance we compute, in this report, the longitudinal impedance of the damping ring vacuum chamber. More specifically we find the response function of the ring to a short gaussian bunch. This function will later be used as a driving term in the longitudinal equation of motion. We also identify the important inductive elements of the vacuum chamber and estimate their contribution to the total ring inductance. This information will be useful in assessing the effect of vacuum chamber modifications. 7 refs. , 8 figs., 1 tab

Internato Longitudinal

Directory of Open Access Journals (Sweden)

Marcelo Marcos Piva Demarzo

Full Text Available O internato médico tem gerado recorrente debate frente às transformações curriculares em andamento no País. A despeito das discussões, um modelo de internato consonante com essas mudanças ainda não foi consistentemente delineado. Neste ensaio, trazemos uma proposta de matriz estruturante para o internato médico. Propomos que o internato médico seja realizado durante os seis anos do curso, de forma longitudinal, tendo como eixo estruturante a clínica da Atenção Básica (AB. Esse modelo de "internato longitudinal" prevê a introdução progressiva na prática clínica, iniciando-se pela AB nos dois primeiros anos, acrescentando-se progressivamente os ambulatórios de especialidades, os estágios hospitalares e demais atividades práticas, alcançando-se, dessa forma, o rol de diversidade e complexidade previsto para o egresso da escola médica.

Longitudinal muscle dysfunction in achalasia esophagus and its relevance.

Science.gov (United States)

Mittal, Ravinder K; Hong, Su Jin; Bhargava, Valmik

2013-04-01

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.

Summary of longitudinal instabilities workshop

Energy Technology Data Exchange (ETDEWEB)

Chasman, R.

1976-01-01

A five-day ISABELLE workshop on longitudinal instabilities was held at Brookhaven, August 9-13, 1976. About a dozen outside accelerator experts, both from Europe and the U.S.A., joined the local staff for discussions of longitudinal instabilities in ISABELLE. An agenda of talks was scheduled for the first day of the workshop. Later during the week, a presentation was given on the subject ''A more rigorous treatment of Landau damping in longitudinal beam instabilities''. A few progress meetings were held in which disagreements regarding calculations of coupling impedances were clarified. A summary session was held on the last day. Heavy emphasis was put on single bunched beam instabilities in the microwave region extending above the cut-off frequency of the ISABELLE vacuum chamber.

Helicity dependence of the total inclusive cross section on the deuteron

International Nuclear Information System (INIS)

Ahrens, J.; Altieri, S.; Annand, J.R.M.; Arends, H.-J.; Beck, R.; Blackston, M.A.; Braghieri, A.; D'Hose, N.; Dutz, H.; Heid, E.; Jahn, O.; Klein, F.; Kondratiev, R.; Lang, M.; Lisin, V.; Martinez Fabregate, M.; McGeorge, J.C.; Meyer, W.; Panzeri, A.; Pedroni, P.

2009-01-01

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200 γ <800 MeV. The experiment used a 4π detection system, a circularly polarized tagged photon beam and a frozen spin target which provided longitudinally polarized deuterons. These new results are a significant improvement on the existing data and allow a detailed comparison with state-of-the-art calculations

Helicity dependence of the total inclusive cross section on the deuteron

Energy Technology Data Exchange (ETDEWEB)

Ahrens, J. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Altieri, S. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, I-27100 Pavia (Italy); Annand, J.R.M. [Department of Physics and Astronomy, University of Glasgow (United Kingdom); Arends, H.-J.; Beck, R. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Blackston, M.A. [Department of Physics, Duke University, Durham, NC 27708 (United States); Braghieri, A. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); D' Hose, N. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette Cedex (France); Dutz, H. [Physikalisches Institut, Universitaet Bonn, D-53115 Bonn (Germany); Heid, E.; Jahn, O. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Klein, F. [Physikalisches Institut, Universitaet Bonn, D-53115 Bonn (Germany); Kondratiev, R. [INR, Academy of Science, Moscow (Russian Federation); Lang, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Lisin, V. [INR, Academy of Science, Moscow (Russian Federation); Martinez Fabregate, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); McGeorge, J.C. [Department of Physics and Astronomy, University of Glasgow (United Kingdom); Meyer, W. [Inst. fuer Experimentalphysik, Ruhr-Universitaet Bochum, D-44801 Bochum (Germany); Panzeri, A. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, I-27100 Pavia (Italy); Pedroni, P. [INFN, Sezione di Pavia, I-27100 Pavia (Italy)], E-mail: pedroni@pv.infn.it (and others)

2009-03-02

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200longitudinally polarized deuterons. These new results are a significant improvement on the existing data and allow a detailed comparison with state-of-the-art calculations.

Cross-sectional and Longitudinal Associations between Knee Joint Effusion Synovitis and Knee Pain in Older Adults.

Science.gov (United States)

Wang, Xia; Jin, Xingzhong; Han, Weiyu; Cao, Yuelong; Halliday, Andrew; Blizzard, Leigh; Pan, Faming; Antony, Benny; Cicuttini, Flavia; Jones, Graeme; Ding, Changhai

2016-01-01

To describe the cross-sectional and longitudinal associations between knee regional effusion synovitis and knee pain in older adults. Data from a population-based random sample (n = 880, mean age 62 yrs, 50% women) were used. Baseline knee joint effusion synovitis was graded (0-3) using T2-weighted magnetic resonance imaging (MRI) in the suprapatellar pouch, central portion, posterior femoral recess, and subpopliteal recess. Effusion synovitis of the whole joint was defined as a score of ≥ 2 in any subregion. Other knee structural (including cartilage, bone marrow, and menisci) lesions were assessed by MRI at baseline. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire at baseline and 2.6 years later. Multivariable analyses were performed after adjustment for age, sex, body mass index, and other structural lesions. The prevalence of effusion synovitis was 67%. Suprapatellar pouch effusion synovitis was significantly and independently associated with increased total and nonweight-bearing knee pain in both cross-sectional and longitudinal analyses (for an increase in total knee pain of ≥ 5, RR 1.26 per grade, 95% CI 1.04-1.52), and increased weight-bearing knee pain in longitudinal analysis only. Effusion synovitis in posterior femoral recess and central portion were independently associated with increases in nonweight-bearing pain (RR 1.63 per grade, 95% CI 1.32-2.01 and RR 1.29 per grade, 95% CI 1.01-1.65, respectively) in longitudinal analyses only. Knee joint effusion synovitis has independent associations with knee pain in older adults. Suprapatellar pouch effusion synovitis is associated with nonweight-bearing and weight-bearing knee pain, while posterior femoral recess and central portion effusion synovitis are only associated with nonweight-bearing pain.

Longitudinal diagnostic efficiency of DSM-IV criteria for obsessive-compulsive personality disorder: a 2-year prospective study.

Science.gov (United States)

Grilo, C M; Skodol, A E; Gunderson, J G; Sanislow, C A; Stout, R L; Shea, M T; Morey, L C; Zanarini, M C; Bender, D S; Yen, S; McGlashan, T H

2004-07-01

To examine the longitudinal diagnostic efficiency of the DSM-IV criteria for obsessive-compulsive personality disorder (OCPD). At baseline, criteria and diagnoses were determined using diagnostic interviews, and blinded assessments were performed 24 months later with 550 participants. Diagnostic efficiency indices (conditional probabilities, total predictive power, and kappa) were calculated for each criterion determined at baseline, using the independent OCPD diagnosis at follow-up as the standard. Longitudinal diagnostic efficiencies for the OCPD criteria varied; findings suggested the overall predictive utility of 'preoccupied with details', 'rigid and stubborn', and 'reluctant to delegate'. These findings suggest the predictive validity of three cognitive-interpersonal OCPD criteria.

Microwave measurements of energy lost to longitudinal modes by single electron bunches traversing periodic structures

International Nuclear Information System (INIS)

Wang, J.W.; Loew, G.A.; Weaver, J.N.; Wilson, P.B.

1981-10-01

In the design of future linear colliders, it will be important to minimize the loss of beam energy due to the excitation of higher-order modes in the accelerator structure by single bunches of electrons or positrons. This loss is not only detrimental in itself but also gives rise to energy spectrum widening and transverse emittance growth. Microwave measurements made on disk-loaded and alternating-spoke structures to determine the loss to the longitudinal modes are described. In these measurements the Gaussian bunch is simulated by a current pulse of the same shape transmitted through the structure on an axial center conductor. Results to date are presented for the total longitudinal loss parameter per period K in volts per picocoulomb

Study of CSR longitudinal bunch compression cavity

International Nuclear Information System (INIS)

Yin Dayu; Li Peng; Liu Yong; Xie Qingchun

2009-01-01

The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring (CSR)is an important issue. Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90 degree rotation in the longitudinal phase space. The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude. For this purpose, the CSR longitudinal bunch compression cavity, loaded with FINEMET-FT-1M is studied and simulated with MAFIA code. In this paper, the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238 U 72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code. The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV, and the cavity can be used to compress heavy ions in the CSR. (authors)

The Chicken and the Egg: Longitudinal Associations between Moral Deficiencies and Bullying: A Parallel Process Latent Growth Model

Science.gov (United States)

Sticca, Fabio; Perren, Sonja

2015-01-01

The present study investigated the longitudinal association between the development of bullying (traditional bullying and cyberbullying) and the development of moral deficiencies (moral disengagement, low moral responsibility, and weak feelings of remorse) during adolescence. A total of 960 Swiss adolescents completed an electronic questionnaire…

Simultaneous maximum a posteriori longitudinal PET image reconstruction

Science.gov (United States)

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.

Longitudinal single-bunch instabilities

International Nuclear Information System (INIS)

Migliorati, M.; Palumbo, L.; Rome Univ. La Sapienza, Rome

2001-02-01

After introducing the concepts of longitudinal wakefield and coupling impedance, it is reviewed the theory of longitudinal single-bunch collective effects in storage rings. From the Fokker-Planck equation it is first derived the stationary solution describing the natural single-bunch regime, and then treat the problem of microwave instability, showing the different approaches used for estimating the threshold current. The lecture is ended with the semi-empirical laws that allow everyone to obtain the single-bunch behaviour above threshold, and with a description of the simulation codes that are now reliable tools for investigating all these effects

LIA longitudinal coupling impedance

International Nuclear Information System (INIS)

Faltens, A.

1980-01-01

The beam generated fields enter into the problems of waveform generation and longitudinal stability. In the former, provision must be made for the longitudinally defocusing forces due to the space charge and the beam loading effects on the accelerating voltage due to the current of a presumably known bunch. In the latter, the concern is for the growth of unintentional perturbations to unacceptably large values through the interaction of the charge and current fluctuations with the rest of the beam and the surrounding structures. These beam generated electric fields may be related to the beam current through a coupling impedance

Longitudinal beam dynamics

International Nuclear Information System (INIS)

Tecker, F

2014-01-01

The course gives a summary of longitudinal beam dynamics for both linear and circular accelerators. After discussing different types of acceleration methods and synchronism conditions, it focuses on the particle motion in synchrotrons

Multilevel predictors of adolescent physical activity: a longitudinal analysis

Directory of Open Access Journals (Sweden)

Hearst Mary O

2012-02-01

Full Text Available Abstract Background To examine how factors from a social ecologic model predict physical activity (PA among adolescents using a longitudinal analysis. Methods Participants in this longitudinal study were adolescents (ages 10-16 at baseline and one parent enrolled in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and Activity (TREC-IDEA and the Etiology of Childhood Obesity (ECHO. Both studies were designed to assess a socio-ecologic model of adolescent obesity risk. PA was collected using ActiGraph activity monitors at two time points 24 months apart. Other measures included objective height and weight, adolescent and parent questionnaires on multilevel psychological, behavioral and social determinants of PA, and a home PA equipment inventory. Analysis was conducted using SAS, including descriptive characteristics, bivariate and stepped multivariate mixed models, using baseline adjustment. Models were stratified by gender. Results There were 578 adolescents with complete data. Results suggest few statistically significant longitudinal associations with physical activity measured as minutes of MVPA or total counts from accelerometers. For boys, greater self-efficacy (B = 0.75, p = 0.01 and baseline MVPA (B = 0.55, p p = 0.01 and barriers (B = -0.32, p = 0.05 significantly predicted MVPA at follow-up in the full model. The full multilevel model explained 30% of the variance in PA among boys and 24% among girls. Conclusions PA change in adolescents is a complex issue that is not easily understood. Our findings suggest early PA habits are the most important predictor of PA levels in adolescence. Intervention may be necessary prior to middle school to maintain PA through adolescence.

Longitudinal Control for Mengshi Autonomous Vehicle via Cloud Model

Science.gov (United States)

Gao, H. B.; Zhang, X. Y.; Li, D. Y.; Liu, Y. C.

2018-03-01

Dynamic robustness and stability control is a requirement for self-driving of autonomous vehicle. Longitudinal control method of autonomous is a key technique which has drawn the attention of industry and academe. In this paper, we present a longitudinal control algorithm based on cloud model for Mengshi autonomous vehicle to ensure the dynamic stability and tracking performance of Mengshi autonomous vehicle. An experiments is applied to test the implementation of the longitudinal control algorithm. Empirical results show that if the longitudinal control algorithm based Gauss cloud model are applied to calculate the acceleration, and the vehicles drive at different speeds, a stable longitudinal control effect is achieved.

Ring RF and longitudinal dynamics in the SNS

International Nuclear Information System (INIS)

Blaskiewicz, M.; Brennan, J.M.; Brodowski, J.; Delong, J.; Meth, M.; Onillon, E.; Zaltsman, A.

2000-01-01

Average beam currents of 40 A will be present in the Spallation Neutron Source. Even though the entire cycle time is only one synchrotron oscillation the longitudinal phase space determines peak beam current and momentum spread. Both factors play a role in space charge and instability dynamics. Longitudinal simulations with beam loading and longitudinal space charge have been done in the design phase

A longitudinal study of neuromelanin-sensitive magnetic resonance imaging in Parkinson's disease.

Science.gov (United States)

Matsuura, Keita; Maeda, Masayuki; Tabei, Ken-Ichi; Umino, Maki; Kajikawa, Hiroyuki; Satoh, Masayuki; Kida, Hirotaka; Tomimoto, Hidekazu

2016-10-28

Neuromelanin-sensitive MR imaging (NMI) is an increasingly powerful tool for the diagnosis of Parkinson's disease (PD). This study was undertaken to evaluate longitudinal changes on NMI in PD patients. We examined longitudinal changes on NMI in 14 PD patients. The area and contrast ratio (CR) of the substantia nigra pars compacta (SNc) were comparatively analyzed. The total area and CR of the SNc upon follow-up NMI were significantly smaller than those on initial NMI (from 33.5±18.9 pixels and 6.35±2.86% to 21.5±16.7 pixels and 4.19±2.11%; Wilcoxon signed-rank test, pWilcoxon signed-rank test, p=0.002 and p=0.007, respectively). On a case-by-case basis, the area of the SNc invariably decreased upon follow-up NMI in all patients. We further demonstrated that the total area and CR of the SNc negatively correlated with disease duration (Pearson correlation coefficient, r=-0.63, p<0.001 and r=-0.41, p=0.031, respectively). In area analyses, our results demonstrated very high intraclass correlation coefficients for both intra- and inter-rater reliability. NMI is a useful and reliable tool for detecting neuropathological changes over time in PD patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Measured longitudinal beam impedance of booster gradient magnets; TOPICAL

International Nuclear Information System (INIS)

James L Crisp and Brian J. Fellenz

2001-01-01

The Booster gradient magnets have no vacuum pipe which forces the beam image current to flow along the laminated pole tips. Both D and F style magnets were measured with a stretched wire to determine the longitudinal beam impedance caused by these laminations. Results are compared to calculations done 30 years ago. The inductive part of the magnet impedance is interesting because it partially compensates for the negative inductance effects of space charge on the beam. An R/L circuit consisting of 37K(center d ot) in parallel with between 40 and 100uH is a reasonable approximation to the total impedance of Booster magnet laminations

Boosted Multivariate Trees for Longitudinal Data

Science.gov (United States)

Pande, Amol; Li, Liang; Rajeswaran, Jeevanantham; Ehrlinger, John; Kogalur, Udaya B.; Blackstone, Eugene H.; Ishwaran, Hemant

2017-01-01

Machine learning methods provide a powerful approach for analyzing longitudinal data in which repeated measurements are observed for a subject over time. We boost multivariate trees to fit a novel flexible semi-nonparametric marginal model for longitudinal data. In this model, features are assumed to be nonparametric, while feature-time interactions are modeled semi-nonparametrically utilizing P-splines with estimated smoothing parameter. In order to avoid overfitting, we describe a relatively simple in sample cross-validation method which can be used to estimate the optimal boosting iteration and which has the surprising added benefit of stabilizing certain parameter estimates. Our new multivariate tree boosting method is shown to be highly flexible, robust to covariance misspecification and unbalanced designs, and resistant to overfitting in high dimensions. Feature selection can be used to identify important features and feature-time interactions. An application to longitudinal data of forced 1-second lung expiratory volume (FEV1) for lung transplant patients identifies an important feature-time interaction and illustrates the ease with which our method can find complex relationships in longitudinal data. PMID:29249866

Secondary health conditions in persons with spinal cord injury : A longitudinal study from one to five years post-discharge

NARCIS (Netherlands)

Adriaansen, Jacinthe J. E.; Post, Marcel W. M.; de Groot, Sonja; van Asbeck, Floris W. A.; Stolwijk-Swuste, Janneke M.; Tepper, Marga; Lindeman, Eline

2013-01-01

Objective: To assess the occurrence of secondary health conditions and their potential risk factors in persons with spinal cord injury from 1 to 5 years after discharge from initial inpatient rehabilitation. Design: Multicentre longitudinal study. Subjects: A total of 139 wheelchair-dependent

Longitudinal and bulk viscosities of Lennard-Jones fluids

Science.gov (United States)

Tankeshwar, K.; Pathak, K. N.; Ranganathan, S.

1996-12-01

Expressions for the longitudinal and bulk viscosities have been derived using Green Kubo formulae involving the time integral of the longitudinal and bulk stress autocorrelation functions. The time evolution of stress autocorrelation functions are determined using the Mori formalism and a memory function which is obtained from the Mori equation of motion. The memory function is of hyperbolic secant form and involves two parameters which are related to the microscopic sum rules of the respective autocorrelation function. We have derived expressions for the zeroth-, second-and fourth- order sum rules of the longitudinal and bulk stress autocorrelation functions. These involve static correlation functions up to four particles. The final expressions for these have been put in a form suitable for numerical calculations using low- order decoupling approximations. The numerical results have been obtained for the sum rules of longitudinal and bulk stress autocorrelation functions. These have been used to calculate the longitudinal and bulk viscosities and time evolution of the longitudinal stress autocorrelation function of the Lennard-Jones fluids over wide ranges of densities and temperatures. We have compared our results with the available computer simulation data and found reasonable agreement.

Longitudinal beam compression for heavy-ion inertial fusion

International Nuclear Information System (INIS)

Ho, D.D.M.; Brandon, S.T.

1991-01-01

A scheme is described for compressing a heavy-ion beam longitudinally in such a way that the compressed pulse has uniform line-charge density and longitudinal momentum. Attaining these conditions will be important in the final focusing of a beam on a small fuel capsule in an inertial confinement fusion reactor. The longitudinal dynamics can be approximately described by a one-dimensional (1-D) fluid model for charged particles. Recognizing the similarity between the 1-D charged particle equations of motion and the 1-D equations for ideal-gas flow permits us to calculate the evolution of the line-charge density and velocity profile using self-similar solutions and the method of characteristics, developed for unsteady supersonic gas dynamics, for different regions along the beam. Simple physical arguments show that although the longitudinal and transverse temperatures vary along the beam following the adiabatic laws, no substantial longitudinal and transverse emittance growth is to be expected. Particle-in-cell simulations confirm all the physical arguments. The compressed beam has negligible longitudinal momentum spread and can therefore avoid chromatic aberrations in final focus. (author) 24 refs., 5 figs., 1 tab

Active Splitting in Longitudinal Power Systems based on a WAMPC

Directory of Open Access Journals (Sweden)

Felipe Arraño-Vargas

2017-12-01

Full Text Available This paper proposes an active splitting scheme especially suitable for longitudinal power systems (LPS. The proposed scheme is based on a modified out-of-step (OOS algorithm combined with an angle difference method using synchrophasor measurements. The remedial actions are based on the detection of possible loss of synchronism due to severe disturbances. The scheme was tested on a detailed dynamic model of the Central Interconnected System of Chile, a good example of extreme LPS. Obtained results show that remedial actions taken by the proposed protection scheme are able to avoid the total collapse of the system during critical contingencies.

Optimized simultaneous transverse and longitudinal focusing of intense ion beam pulses for warm dense matter applications

International Nuclear Information System (INIS)

Sefkow, Adam B.; Davidson, Ronald C.; Kaganovich, Igor D.; Gilson, Erik P.; Roy, Prabir K.; Seidl, Peter A.; Yu, Simon S.; Welch, Dale R.; Rose, David V.; Barnard, John J.

2007-01-01

Intense, space-charge-dominated ion beam pulses for warm dense matter and heavy ion fusion applications must undergo simultaneous transverse and longitudinal bunch compression in order to meet the requisite beam intensities desired at the target. The longitudinal compression of an ion bunch is achieved by imposing an initial axial velocity tilt on the drifting beam and subsequently neutralizing its space-charge and current in a drift region filled with high-density plasma. The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory has measured a sixty-fold longitudinal current compression of an intense ion beam with pulse duration of a few nanoseconds, in agreement with simulations and theory. A strong solenoid is modeled near the end of the drift region in order to transversely focus the beam to a sub-millimeter spot size coincident with the longitudinal focal plane. The charge and current neutralization provided by the background plasma is critical in determining the total achievable transverse and longitudinal compression of the beam pulse. Numerical simulations show that the current density of an NDCX ion beam can be compressed over a few meters by factors greater than 10 5 with peak beam density in excess of 10 14 cm -3 . The peak beam density sets a lower bound on the local plasma density required near the focal plane for optimal beam compression, since the simulations show stagnation of the compression when n beam >n plasma . Beam-plasma interactions can also have a deleterious effect on the compression physics and lead to the formation of nonlinear wave excitations in the plasma. Simulations that optimize designs for the simultaneous transverse and longitudinal focusing of an NDCX ion beam for future warm dense matter experiments are discussed

Longitudinal research and data collection in primary care.

Science.gov (United States)

van Weel, Chris

2005-01-01

This article reviews examples of and experience with longitudinal research in family medicine. The objective is to use this empirical information to formulate recommendations for improving longitudinal research. The article discusses 3 longitudinal studies from the Nijmegen academic family practice research network: 1 on the prognosis of depression and 1 each on the prognosis of and outcomes of care for type 2 diabetes mellitus. The Nijmegen network has recorded all episodes of morbidity encountered in Dutch family medicine since 1971 in a stable practice population. This network's experience is evaluated to identify lessons that may help other practice-based research networks (PBRNs) in pursuing longitudinal research. In terms of external conditions (conditions related to the general setting), the stability of a population and a high level of continuity of care substantially enhance the ability to perform longitudinal research. In terms of internal conditions (conditions related to the PBRN), motivation of family physicians and their staff to conduct ongoing data collection, and their ownership of the data are key for success. Other critical internal conditions include standardization of data; collection of data by clinician-friendly means; training of family physicians and their staff in data collection, as well as meetings for discussion of this task; provision of feedback to practices on the research findings; use of standard procedures to promote adherence to data collection; availability of facilities for regular measurement of patients' health status or chart review; and use of mechanisms for tracking patients who leave the practice area. Insight from existing experience suggests that longitudinal research can be enhanced in PBRNs. The best way forward is to build longitudinal data collection by drawing on lessons from successful studies. Primary care research policy should advocate for a role of longitudinal research and stimulate its development in PBRNs

Longitudinal drop-out and weighting against its bias

Directory of Open Access Journals (Sweden)

Steffen C. E. Schmidt

2017-12-01

Full Text Available Abstract Background The bias caused by drop-out is an important factor in large population-based epidemiological studies. Many studies account for it by weighting their longitudinal data, but to date there is no detailed final approach for how to conduct these weights. Methods In this study we describe the observed longitudinal bias and a three-step longitudinal weighting approach used for the longitudinal data in the MoMo baseline (N = 4528, 4–17 years and wave 1 study with 2807 (62% participants between 2003 and 2012. Results The most meaningful drop-out predictors were socioeconomic status of the household, socioeconomic characteristics of the mother and daily TV usage. Weighting reduced the bias between the longitudinal participants and the baseline sample, and also increased variance by 5% to 35% with a final weighting efficiency of 41.67%. Conclusions We conclude that a weighting procedure is important to reduce longitudinal bias in health-oriented epidemiological studies and suggest identifying the most influencing variables in the first step, then use logistic regression modeling to calculate the inverse of the probability of participation in the second step, and finally trim and standardize the weights in the third step.

A retrospective longitudinal study of animal and human rabies in Botswana 1989-2006

OpenAIRE

K.T. Moagabo; K.B. Monyame; E.K. Baipoledi; M. Letshwenyo; N. Mapitse; J.M.K. Hyera

2009-01-01

A longitudinal study of animal and human rabies covering 18 years from 1989 to 2006 was retrospectively conducted in order to highlight the epidemiological features and trends of the disease in Botswana. Over the 18-year period, a total of 4 306 brain specimens collected from various species of animals including human beings with clinical signs consistent with rabies were submitted to the National Veterinary Laboratory in Gaborone for confirmatory diagnosis. Of the samples submitted, 2 ...

Longitudinal feedback system for PEP

International Nuclear Information System (INIS)

Allen, M.A.; Cornacchia, M.; Millich, A.

1979-02-01

Whether the wide bandwidth longitudinal feedback system described in this paper is made to act on the individual modes in frequency domain or on the individual bunches in time domain, it represents a clean and efficient way of damping the longitudinal oscillations without influencing other beam parameters such as bunch shape or synchrotron frequency distribution. The frequency domain feedback presents the advantage of providing information on which modes are unstable and on their risetimes, which may be helpful in locating dangerous resonators in the ring

Longitudinal fluctuations and decorrelation of anisotropic flow

Energy Technology Data Exchange (ETDEWEB)

Pang, Long-Gang [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Petersen, Hannah [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Qin, Guang-You [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Roy, Victor [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Wang, Xin-Nian [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Nuclear Science Division MS70R0319, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2016-12-15

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.

Posterior longitudinal ligament status in cervical spine bilateral facet dislocations

International Nuclear Information System (INIS)

Carrino, John A.; Manton, Geoffrey L.; Morrison, William B.; Flanders, Adam E.; Vaccaro, Alex R.; Schweitzer, Mark E.

2006-01-01

It is generally accepted that cervical spine bilateral facet dislocation results in complete disruption of the posterior longitudinal ligament. The goal of this study was to evaluate the integrity of numerous spine-stabilizing structures by MRI, and to determine if any associations between injury patterns exist with respect to the posterior longitudinal ligament status. Retrospective case series. A retrospective review was performed of 30 cervical spine injury subjects with bilateral facet dislocation. Assessment of 1.5T MRI images was carried out for: intervertebral disc disruption, facet fracture, and ligamentous disruption. Statistical analyses were performed to evaluate for associations between various injury patterns and posterior longitudinal ligament status. The frequency of MRI abnormalities was: anterior longitudinal ligament disruption (26.7%), disc herniation or disruption (90%), posterior longitudinal ligament disruption (40%), facet fracture (63.3%) and disruption of the posterior column ligament complex (97%). There were no significant associations between injury to the posterior longitudinal ligament and other structures. Compared to surgical reports, MRI was accurate for determining the status for 24 of 26 ligaments (three of three anterior longitudinal ligament, seven of nine posterior longitudinal ligament, and 14 of 14 posterior column ligament complex) but generated false negatives in two instances (in both MRI showed an intact posterior longitudinal ligament that was torn at surgery). (orig.)

Influencia de la buccalina ® en la concentración de streptococcus mutans en saliva total

OpenAIRE

Guardia Mendez, Gustavo

2015-01-01

Se realizó un estudio longitudinal en 28 niños de 6 años de edad para determinar la influencia de la BUCCALINA ® en la concentración de Streptococcus mutans en saliva total. Se midió la concentración de Streptococcus mutans en saliva total de todos los niños antes del experimento. 14 niños escogidos al azar recibieron la vacuna y 14 recibieron placebo. A los 37 días se midió la concentración de Streptococcus mutans en saliva total de todos los niños. Se usó la “t” de student para determinar l...

Existence of longitudinal waves in pre-stressed anisotropic elastic ...

Indian Academy of Sciences (India)

waves is truly longitudinal. Longitudinal wave in an anisotropic elastic medium is defined as the wave motion in which the particle motion (i.e., the. Keywords. General anisotropy; elastic stiffness; pre-stress; group velocity; ray direction; longitudinal waves; polarization. J. Earth Syst. Sci. 118, No. 6, December 2009, pp. 677– ...

Longitudinal relations between adolescents' materialism and prosocial behavior toward family, friends, and strangers.

Science.gov (United States)

Yang, Zhixu; Fu, Xinyuan; Yu, Xiaoxia; Lv, Yichen

2018-01-01

The present study examines the short-term changes and longitudinal relations between adolescents' materialism and prosocial behavior toward family, friends, and strangers over a year. A total of 434 Chinese adolescents (mean age at Time 1 = 11.27; 54% girls) participated in the two time points. From 6 th grade to 7 th grade, boys' and girls' materialism increased, whereas their prosocial behavior toward family, friends, and strangers declined, despite the stable trend in boys' prosocial behavior toward strangers. Furthermore, a cross-lagged model was conducted and the results showed that, adolescent materialism was associated longitudinally with decreased prosocial behavior toward friends and strangers, but not toward family. However, earlier prosocial behavior toward family, friends, and strangers were not associated with subsequent adolescent materialism. The findings point toward an understanding of materialism as a precursor rather than an outcome or byproduct to prosocial behavior. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Parameter optimization method for longitudinal vibration absorber of ship shaft system

Directory of Open Access Journals (Sweden)

LIU Jinlin

2017-05-01

Full Text Available The longitudinal vibration of the ship shaft system is the one of the most important factors of hull stern vibration, and it can be effectively minimized by installing a longitudinal vibration absorber. In this way, the vibration and noise of ships can be brought under control. However, the parameters of longitudinal vibration absorbers have a great influence on the vibration characteristics of the shaft system. As such, a certain shafting testing platform was studied as the object on which a finite model was built, and the relationship between longitudinal stiffness and longitudinal vibration in the shaft system was analyzed in a straight alignment state. Furthermore, a longitudinal damping model of the shaft system was built in which the parameters of the vibration absorber were non-dimensionalized, the weight of the vibration absorber was set as a constant, and an optimizing algorithm was used to calculate the optimized stiffness and damping coefficient of the vibration absorber. Finally, the longitudinal vibration frequency response of the shafting testing platform before and after optimizing the parameters of the longitudinal vibration absorber were compared, and the results indicated that the longitudinal vibration of the shafting testing platform was decreased effectively, which suggests that it could provide a theoretical foundation for the parameter optimization of longitudinal vibration absorbers.

Investigating strengths and deficits to increase work engagement: A longitudinal study in the mining industry

Directory of Open Access Journals (Sweden)

Pule Mphahlele

2018-02-01

Full Text Available Orientation: The motivational process of the Job Demands-Resources (JD-R model indicates that job resources are the main predictors of work engagement. Previous research has found that the two job resources perceived organisational support (POS for strengths use and POS for deficit correction are also positively related to work engagement. However, the causal relationships between these variables have not been investigated longitudinally. Research purpose: To determine if POS for strengths use and POS for deficit correction are significant predictors of work engagement over time. Motivation for the study: In the literature, empirical evidence on the longitudinal relationships between work engagement and specific job resources, namely POS for strengths use and POS for deficit correction, is limited. Research design, approach and method: A longitudinal design was employed in this study. The first wave elicited a total of 376 responses, while the second wave had a total sample size of 79. A web-based survey was used to measure the constructs and to gather data at both points in time. Structural equation modelling was used to investigate the hypotheses. Main findings: The results indicated that both POS for strengths use and POS for deficit correction are positively related to work engagement in the short term. However, only POS for deficit correction significantly predicted work engagement over time. Practical and managerial implications: The results provide valuable insights to organisations by providing knowledge regarding which approach influences work engagement levels of their employees in the short and long term. Contribution or value-add: The study contributes to the limited research on what job resources predict work engagement over time.

Longitudinal- and transverse-wake-field effects in dielectric structures

International Nuclear Information System (INIS)

Rosing, M.; Gai, W.

1990-01-01

A dielectric-loaded circular waveguide structure is a potential high-gradient linear wake-field accelerator. A complete solution is given for the longitudinal electric and magnetic fields excited by a δ function and a Gaussian charge distribution moving parallel to the guide axis. The fields are then given in the limit of particle velocity equal to the speed of light. Example calculations are given for a structure with inner radius of 2 mm, outer radius of 5 mm, dielectric constant of 3, and total charge of 100 nC. Peak wake fields in excess of 200 MV/m are found. Azimuthal modes 0 and 1 are investigated for the particular interest of acceleration and deflection problems

The longitudinal impact of depression on disability in Parkinson disease.

Science.gov (United States)

Pontone, Gregory M; Bakker, Catherine C; Chen, Shaojie; Mari, Zoltan; Marsh, Laura; Rabins, Peter V; Williams, James R; Bassett, Susan S

2016-05-01

Depression in Parkinson disease (PD) is a common problem that worsens quality of life and causes disability. However, little is known about the longitudinal impact of depression on disability in PD. This study examined the association between disability and DSM-IV-TR depression status across six years. Longitudinal cohort study with assessments at study entry, year two, four, and six conducted in the Morris K. Udall Parkinson Disease Research Center. Recruitment totaled 137 adult men and women with idiopathic PD in which up to six years of data on demographic, motor, and non-motor variables was collected. Movement disorder specialists used the structured interview for DSM-IV-TR depressive disorders and the Northwestern Disability Scale to assess depression and disability. A generalized linear mixed model was fitted with Northwestern Disability Scale score as the dependent variable to determine the effect of baseline depression status on disability. A total of 43 participants were depressed at baseline compared to 94 without depression. Depressed participants were more likely to be female, were less educated, were less likely to take dopamine agonists, and more likely to have motor fluctuations. Controlling for these variables, symptomatic depression predicted greater disability compared to both never depressed (p = 0.0133) and remitted depression (p = 0.0009). Disability associated with symptomatic depression at baseline was greater over the entire six-year period compared to participants with remitted depressive episodes or who were never depressed. Persisting depression is associated with a long-term adverse impact on daily functioning in PD. Adequate treatment or spontaneous remission of depression improves ADL function. Copyright © 2015 John Wiley & Sons, Ltd.

Modelling, simulation and applications of longitudinal train dynamics

Science.gov (United States)

Cole, Colin; Spiryagin, Maksym; Wu, Qing; Sun, Yan Quan

2017-10-01

Significant developments in longitudinal train simulation and an overview of the approaches to train models and modelling vehicle force inputs are firstly presented. The most important modelling task, that of the wagon connection, consisting of energy absorption devices such as draft gears and buffers, draw gear stiffness, coupler slack and structural stiffness is then presented. Detailed attention is given to the modelling approaches for friction wedge damped and polymer draft gears. A significant issue in longitudinal train dynamics is the modelling and calculation of the input forces - the co-dimensional problem. The need to push traction performances higher has led to research and improvement in the accuracy of traction modelling which is discussed. A co-simulation method that combines longitudinal train simulation, locomotive traction control and locomotive vehicle dynamics is presented. The modelling of other forces, braking propulsion resistance, curve drag and grade forces are also discussed. As extensions to conventional longitudinal train dynamics, lateral forces and coupler impacts are examined in regards to interaction with wagon lateral and vertical dynamics. Various applications of longitudinal train dynamics are then presented. As an alternative to the tradition single wagon mass approach to longitudinal train dynamics, an example incorporating fully detailed wagon dynamics is presented for a crash analysis problem. Further applications of starting traction, air braking, distributed power, energy analysis and tippler operation are also presented.

KARAKTERISTIK SIFAT FISIK KAYU JABON(Anthocephalus cadamba Miq PADA ARAH LONGITUDINAL DAN RADIAL

Directory of Open Access Journals (Sweden)

Ary Widiyanto

2017-06-01

Full Text Available This study aims to investigate the characteristics of the physical properties of jabon (Anthocephalus cadambaMiq. wood and its variations in the stem longitudinaland radial direction. A total of 3samplesof jabontrees were taken from private forest in Talagawangi Village, Pakenjeng sub-District, Garut District, West Java Province. Speciments of physical properties were taken at 3 different heightsof the longitudinal direction(bottom, midle and top of trunkas well as 3 differentradialdirections (near pith, middle and near barkof the jabontrunk. The observation focused on the physical properties in three position of both longitudinal and radial orientation. The parameters observed were green wood moisture content(GMC, air-driedmoisture content (ADMC, specific gravity on green wood moisture volume (SGG, and specific gravity on air-dried moisture volume (SGAD. Result showed that the average of GMC and ADMC of jabon wood were 118,43% and 15.36% respectively, while SGG and SGAD are 0.33 and 0.37 respectively.The specific gravity (both SGG and SGAD of jabon wood was significantly differencein bothlongitudinal and radial direction; while the ADMC and FMC were not significantly difference for longitudinal direction but significantly difference for radial direction. On radial direction, the GMC decreased from the pith to midle and increased near ther bark; while the ADMC regularly decreased from the pith to bark. The specific gravity value on the longitudinaldirection consistently increases from the bottom of the trunk to the top. On radial direction, the specific gravity value consistently increases from the pith to near the bark. Penelitian ini bertujuan untuk mengetahui karakteristik sifat fisik kayu jabon (Anthocepalus cadamba Miq dan variasinya pada arah longitudinal dan radial batang.Sebanyak 3 pohon, masing-masing diambil sampel 3 titik pada arah longitudinal dan radial batang kayu jabondiambil dari hutan rakyat Desa Talagawangi, Kecamatan Pakenjeng

The Role of Personal Best (PB) and Dichotomous Achievement Goals in Students' Academic Motivation and Engagement: A Longitudinal Investigation

Science.gov (United States)

Martin, Andrew J.; Elliot, Andrew J.

2016-01-01

This study assessed the role of prior personal best goals in predicting subsequent academic motivation and engagement. A total of 1160 high school students participated in a longitudinal survey study exploring the extent to which personal best and mastery and performance (dichotomous) achievement goals predict students' academic motivation and…

Vitamin D and Male Sexual Function: A Transversal and Longitudinal Study.

Science.gov (United States)

Tirabassi, Giacomo; Sudano, Maurizio; Salvio, Gianmaria; Cutini, Melissa; Muscogiuri, Giovanna; Corona, Giovanni; Balercia, Giancarlo

2018-01-01

The effects of vitamin D on sexual function are very unclear. Therefore, we aimed at evaluating the possible association between vitamin D and sexual function and at assessing the influence of vitamin D administration on sexual function. We retrospectively studied 114 men by evaluating clinical, biochemical, and sexual parameters. A subsample ( n = 41) was also studied longitudinally before and after vitamin D replacement therapy. In the whole sample, after performing logistic regression models, higher levels of 25(OH) vitamin D were significantly associated with high values of total testosterone and of all the International Index of Erectile Function (IIEF) questionnaire parameters. On the other hand, higher levels of total testosterone were positively and significantly associated with high levels of erectile function and IIEF total score. After vitamin D replacement therapy, total and free testosterone increased and erectile function improved, whereas other sexual parameters did not change significantly. At logistic regression analysis, higher levels of vitamin D increase (Δ-) were significantly associated with high values of Δ-erectile function after adjustment for Δ-testosterone. Vitamin D is important for the wellness of male sexual function, and vitamin D administration improves sexual function.

Continuity of Genetic and Environmental Influences on Cognition across the Life Span: A Meta-Analysis of Longitudinal Twin and Adoption Studies

Science.gov (United States)

Tucker-Drob, Elliot M.; Briley, Daniel A.

2014-01-01

The longitudinal rank-order stability of cognitive ability increases dramatically over the lifespan. Multiple theoretical perspectives have proposed that genetic and/or environmental mechanisms underlie the longitudinal stability of cognition, and developmental trends therein. However, the patterns of stability of genetic and environmental influences on cognition over the lifespan largely remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically-informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,538 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 non-adoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were low during early childhood, increased sharply over child development, and remained relatively high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and increased gradually to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment interaction and correlation. PMID:24611582

Upper-extremity phocomelia reexamined: a longitudinal dysplasia.

Science.gov (United States)

Goldfarb, Charles A; Manske, Paul R; Busa, Riccardo; Mills, Janith; Carter, Peter; Ezaki, Marybeth

2005-12-01

In contrast to longitudinal deficiencies, phocomelia is considered a transverse, intercalated segmental dysplasia. Most patients demonstrate severe, but not otherwise classifiable, upper-extremity deformities, which usually cannot be placed into one of three previously described phocomelia groups. Additionally, these phocomelic extremities do not demonstrate true segmental deficits; the limb is also abnormal proximal and distal to the segmental defect. The purpose of this investigation was to present evidence that upper-extremity abnormalities in patients previously diagnosed as having phocomelia in fact represent a proximal continuum of radial or ulnar longitudinal dysplasia. The charts and radiographs of forty-one patients (sixty extremities) diagnosed as having upper-extremity phocomelia were reviewed retrospectively. On the basis of the findings on the radiographs, the disorders were categorized into three groups: (1) proximal radial longitudinal dysplasia, which was characterized by an absent proximal part of the humerus, a nearly normal distal part of the humerus, a completely absent radius, and a radial-sided hand dysplasia; (2) proximal ulnar longitudinal dysplasia, characterized by a short one-bone upper extremity that bifurcated distally and by severe hand abnormalities compatible with ulnar dysplasia; and (3) severe combined dysplasia, with type A characterized by an absence of the forearm segment (i.e., the radius and ulna) and type B characterized by absence of the arm and forearm (i.e., the hand attached to the thorax). Twenty-nine limbs in sixteen patients could be classified as having proximal radial longitudinal dysplasia. Systemic medical conditions such as thrombocytopenia-absent radius syndrome were common in those patients, but additional musculoskeletal conditions were rare. Twenty limbs in seventeen patients could be classified as having proximal ulnar longitudinal dysplasia. Associated musculoskeletal abnormalities, such as proximal femoral

Sequential Progressions in a Theory of Mind Scale: Longitudinal Perspectives

Science.gov (United States)

Wellman, Henry M.; Fuxi, Fang; Peterson, Candida C.

2011-01-01

Consecutive re-testings of 92 U.S. preschoolers (n = 30), Chinese preschoolers (n = 31), and deaf children (n = 31) examined whether the sequences of development apparent in cross-sectional results with a theory-of-mind scale also appeared in longitudinal assessment. Longitudinal data confirmed that theory-of-mind progressions apparent in cross-sectional scaling data also characterized longitudinal sequences of understanding for individual children. The match between cross-sectional and longitudinal sequences appeared for children who exhibit different progressions across cultures (U.S. vs. China) and for children with substantial delays (deaf children of hearing parents). Moreover, greater scale distances reflected larger longitudinal age differences. PMID:21428982

Requirements for longitudinal HOM damping in superconducting recirculating linacs

International Nuclear Information System (INIS)

Bisognano, J.J.; Fripp, M.L.

1989-01-01

Transverse beam breakup provides the primary current limitation in the operation of superconducting recirculating linacs and requires the significant damping of transverse-deflecting higher order modes. The need to damp the coexisting longitudinal HOMs in these nominally isochronous machines, however, is not as clear. Isochronicity implies that energy variations induced by excitation of longitudinal modes do not translate directly into position and current modulations. Such modulations, if present, could enhance the initial excitation, effectively closing a potentially unstable feedback loop. Design optimization of cavity structures may suggest that no longitudinal damping be provided. On the other hand, easing of the isochronicity requirement may provide desired flexibility in lattice design. In this note, limits are placed on the requirements for longitudinal HOM damping and on the tolerances for isochronicity which are driven by possible longitudinal multipass phenomena. 2 refs., 1 fig

Effect of loading pattern on longitudinal bowing in flexible roll forming

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Hyun; Woo, Young Yun; Hwang, Tae Woo; Han, Sang Wook; Moon, Young Hoon [School of Mechanical Engineering, Engineering Research Center for Net Shape and Die Manufacturing, Pusan National University,Busan (Korea, Republic of)

2016-12-15

The flexible roll forming process can be used to fabricate products with a variable cross-section profile in the longitudinal direction. Transversal nonuniformity of the longitudinal strain is one of the fundamental characteristics of blank deformation in flexible roll forming. Longitudinal bowing is a shape defect caused by transversal nonuniformity of the longitudinal strain. In this study, loading patterns in flexible roll forming are investigated in order to reduce the longitudinal bowing in a roll-formed blank. To analyze the effects of loading patterns on longitudinal bowing, two different forming schedules are implemented. In schedule 1, loading patterns with different bending angle increments are designed under fixed initial and final bending angles. In schedule 2, loading patterns with different initial bending angles under the fixed final bending angle are designed. Our results show that the bowing heights are significantly affected by the loading patterns. The bowing susceptibilities vary with blank shape such as trapezoid, convex, and concave shapes. In addition to the peak longitudinal strain at the respective roll stands, the cumulative longitudinal strain from the initial to final stands is shown to be a reliable index in predicting the tendency of longitudinal bowing.

College Women's Female Friendships: A Longitudinal View

Science.gov (United States)

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…

14 CFR 23.173 - Static longitudinal stability.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 23.173... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with the airplane trimmed as indicated, the characteristics of the elevator control forces and the friction within...

The dorsal tectal longitudinal column (TLCd): a second longitudinal column in the paramedian region of the midbrain tectum.

Science.gov (United States)

Aparicio, M-Auxiliadora; Saldaña, Enrique

2014-03-01

The tectal longitudinal column (TLC) is a longitudinally oriented, long and narrow nucleus that spans the paramedian region of the midbrain tectum of a large variety of mammals (Saldaña et al. in J Neurosci 27:13108-13116, 2007). Recent analysis of the organization of this region revealed another novel nucleus located immediately dorsal, and parallel, to the TLC. Because the name "tectal longitudinal column" also seems appropriate for this novel nucleus, we suggest the TLC described in 2007 be renamed the "ventral tectal longitudinal column (TLCv)", and the newly discovered nucleus termed the "dorsal tectal longitudinal column (TLCd)". This work represents the first characterization of the rat TLCd. A constellation of anatomical techniques was used to demonstrate that the TLCd differs from its surrounding structures (TLCv and superior colliculus) cytoarchitecturally, myeloarchitecturally, neurochemically and hodologically. The distinct expression of vesicular amino acid transporters suggests that TLCd neurons are GABAergic. The TLCd receives major projections from various areas of the cerebral cortex (secondary visual mediomedial area, and granular and dysgranular retrosplenial cortices) and from the medial pretectal nucleus. It densely innervates the ipsilateral lateral posterior and laterodorsal nuclei of the thalamus. Thus, the TLCd is connected with vision-related neural centers. The TLCd may be unique as it constitutes the only known nucleus made of GABAergic neurons dedicated to providing massive inhibition to higher order thalamic nuclei of a specific sensory modality.

A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states

Energy Technology Data Exchange (ETDEWEB)

Beddo, M.E.

1990-10-01

A measurement off {Delta}{sigma}{sub L}(np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD{sub 2}). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0{degree}. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD{sub 2} target. The experimental values of {Delta}{sigma}{sub L}(np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from {Delta}{sigma}{sub L}(np) using existing pp data (I = 1), with the unexpected result that {Delta}{sigma}{sub L}(I = 0) was found to be essentially identical in shape to {Delta}{sigma}{sub L}(I = 1). The significance of this is not yet understood.

Variable selection and estimation for longitudinal survey data

KAUST Repository

Wang, Li; Wang, Suojin; Wang, Guannan

2014-01-01

There is wide interest in studying longitudinal surveys where sample subjects are observed successively over time. Longitudinal surveys have been used in many areas today, for example, in the health and social sciences, to explore relationships

The Role of Microsimulation in Longitudinal Data Analysis

Directory of Open Access Journals (Sweden)

Douglas A. Wolf

2001-12-01

microsimulation also has the potential to contribute to longitudinal data analysis in several ways, including extending the range of outputs generated by a model, addressing several defective-data problems, and serving as a vehicle for missing-data imputation. This paper discusses microsimulation procedures suitable for several commonly-used statistical models applied to longitudinal data. It also addresses the unique role that can be played by microsimulation in longitudinal data analysis, and the problem of accounting for the several sources of variability associated with microsimulation procedures.

SCI Longitudinal Aging Study: 40 Years of Research.

Science.gov (United States)

Krause, James S; Clark, Jillian M R; Saunders, Lee L

2015-01-01

The Spinal Cord Injury (SCI) Longitudinal Aging Study was initiated in 1973 and has conducted 8 assessments over the past 40 years. It was designed to help rehabilitation professionals understand the life situation of people with SCI, but it has developed into the most long-standing study of aging and SCI and has resulted in over 50 publications. Our purpose was to provide a detailed history of the study, response patterns, utilization of measures, and a summary of key findings reported in the literature. Five participant samples have been incorporated over the 40 years, with enrollment in 1973, 1984, 1993 (2 samples), and 2003. A total of 2,208 participants have completed 6,001 assessments, with a particularly large number of assessments among those who are more than 40 years post injury (n = 349). The overall results have indicated changing patterns of outcomes over time as persons with SCI age, with some notable declines in participation and health. There has been a survivor effect whereby persons who are more active, well-adjusted, and healthier live longer. This study has several important features that are required for longitudinal research including (a) consistency of follow-up, (b) consistency of measures over time, (c) addition of new participant samples to counteract attrition, and (d) inclusion of a large number of individuals who have reached aging milestones unparalleled in the literature. Data from this study can inform the literature on the natural course of aging with SCI.

Longitudinal dynamics in storage rings

International Nuclear Information System (INIS)

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

Passive longitudinal phase space linearizer

Directory of Open Access Journals (Sweden)

P. Craievich

2010-03-01

Full Text Available We report on the possibility to passively linearize the bunch compression process in electron linacs for the next generation x-ray free electron lasers. This can be done by using the monopole wakefields in a dielectric-lined waveguide. The optimum longitudinal voltage loss over the length of the bunch is calculated in order to compensate both the second-order rf time curvature and the second-order momentum compaction terms. Thus, the longitudinal phase space after the compression process is linearized up to a fourth-order term introduced by the convolution between the bunch and the monopole wake function.

Longitudinal instability of an induction linac with acceleration

International Nuclear Information System (INIS)

Smith, L.; Lee, E.P.

1993-05-01

The question arises as to what effect acceleration, which so far has been ignored, has on the longitudinal instability of an induction linac. The answer is not much for the anticipated acceleration rate (1--2 MeV/m) and minimum e-folding distance for the instability (50--500 meters). However, total unstable growth is significantly reduced over distances which are long enough for appreciable acceleration to occur. The purpose of this note is to record a calculation of the instability, including a constant acceleration rate. Some interesting features emerge -- for example, the velocity of the head is a more convenient independent variable than axial position and, for an initial sinusoidal perturbation of velocity in time, the number of oscillations along the pulse is constant; as the pulse shortens in nine the frequency increases

Approaching maximal performance of longitudinal beam compression in induction accelerator drivers

International Nuclear Information System (INIS)

Mark, J.W.K.; Ho, D.D.M.; Brandon, S.T.; Chang, C.L.; Drobot, A.T.; Faltens, A.; Lee, E.P.; Krafft, G.A.

1986-01-01

Longitudinal beam compression is an integral part of the US induction accelerator development effort for heavy ion fusion. Producing maximal performance for key accelerator components is an essential element of the effort to reduce driver costs. We outline here initial studies directed towards defining the limits of final beam compression including considerations such as: maximal available compression, effects of longitudinal dispersion and beam emittance, combining pulse-shaping with beam compression to reduce the total number of beam manipulations, etc. The use of higher ion charge state Z greater than or equal to 3 is likely to test the limits of the previously envisaged beam compression and final focus hardware. A more conservative approach is to use additional beamlets in final compression and focus. On the other end of the spectrum of choices, alternate approaches might consider new final focus with greater tolerances for systematic momentum and current variations. Development of such final focus concepts would also allow more compact (and hopefully cheaper) hardware packages where the previously separate processes of beam compression, pulse-shaping and final focus occur as partially combined and nearly concurrent beam manipulations

Assessment of pituitary adenoma volumetric change using longitudinal MR image registration

International Nuclear Information System (INIS)

Ringstad, Geir Andre; Hald, John K.; Emblem, Kyrre Eeg; Holland, Dominic; Dale, Anders M.; Bjornerud, Atle

2012-01-01

Change detection is a crucial factor in monitoring of slowly evolving pathologies. The objective of the study was to test a semi-automatic method applied on longitudinal MRI monitoring of volume change in pituitary macroadenomas. The proposed method is based on a visual comparison of geometrically corrected, co-registered, intensity-normalized contrast-enhanced (CE) 3D GRE T1-weighted images. Qualitative volume changes based on this applied method were compared with experts' readings of conventional pre- and post-CE 2D T1-weighted images. Magnetic resonance (MR) imaging was performed two to four times in 13 patients with a total combination of 29 time points. Compared to conventional 2D MR readings, a diagnosis of tumor growth (yes/no) was changed in 5 of 13 patients (38%) at 9 of the 29 combinations of time points (31%) using the 3D-based semi-automatic method. With manual tumor tracings as reference, McNemar's test showed a significant difference between the two methods. Visual comparison of geometrically corrected, intensity-normalized, and affine-aligned longitudinal 3D images may enable more accurate assessment of qualitative volumetric change in pituitary adenomas than conventional reading of 2D images. (orig.)

Nontraumatic tibial polyethylene insert cone fracture in mobile-bearing posterior-stabilized total knee arthroplasty

OpenAIRE

Tanikake, Yohei; Hayashi, Koji; Ogawa, Munehiro; Inagaki, Yusuke; Kawate, Kenji; Tomita, Tetsuya; Tanaka, Yasuhito

2016-01-01

A 72-year-old male patient underwent mobile-bearing posterior-stabilized total knee arthroplasty for osteoarthritis. He experienced a nontraumatic polyethylene tibial insert cone fracture 27 months after surgery. Scanning electron microscopy of the fracture surface of the tibial insert cone suggested progress of ductile breaking from the posterior toward the anterior of the cone due to repeated longitudinal bending stress, leading to fatigue breaking at the anterior side of the cone, followed...

Longitudinal Electroproduction of Charged Pions from

International Nuclear Information System (INIS)

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

2001-01-01

Separated longitudinal and transverse cross sections for charged pion electroproduction from 1 H, 2 H, and 3 He were measured at Q 2 = 0.4 (GeV/c) 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 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

Longitudinal Muscle Dysfunction in Achalasia Esophagus and Its Relevance

OpenAIRE

Mittal, Ravinder K; 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...

Local time, seasonal, and solar cycle dependency of longitudinal variations of TEC along the crest of EIA over India

Science.gov (United States)

Sunda, Surendra; Vyas, B. M.

2013-10-01

global wave number 4 structure in the Indian longitudinal region spanning from ~70 to 95°E forming the upward slope of the peak in the total electron content (TEC) are reported along the crest of equatorial ionization anomaly (EIA). The continuous and simultaneous measurements from five GPS stations of GPS Aided Geo Augmented Navigation (GAGAN) network are used in this study. The long-term database (2004-2012) is utilized for examining the local time, seasonal, and solar cycle dependency on the longitudinal variations of TEC. Our results confirm the existence of longitudinal variations of TEC in accordance with wave number 4 longitudinal structure including its strength. The results suggest that these variations, in general, start to develop at ~09 LT, achieve maximum strength at 12-15 LT, and decay thereafter, the decay rate depending on the season. They are more pronounced in equinoctial season followed by summer and winter. The longitudinal variations persist beyond midnight in equinox seasons, whereas in winter, they are conspicuously absent. Interestingly, they also exhibit significant solar cycle dependence in the solstices, whereas in the equinoxes, they are independent of solar activity. The comparison of crest-to-trough ratio (CTR) in the eastern (92°E) and western (72°E) extreme longitudes reveals higher CTR on the eastern side than over the western extreme, suggesting the role of nonmigrating tides in modulating the ExB vertical drift and the consequential EIA crest formation.

Longitudinal Diffusion Tensor Imaging-Based Assessment of Tract Alterations: An Application to Amyotrophic Lateral Sclerosis

Directory of Open Access Journals (Sweden)

Dobri Baldaranov

2017-12-01

Full Text Available Objective: The potential of magnetic resonance imaging (MRI as a technical biomarker for cerebral microstructural alterations in neurodegenerative diseases is under investigation. In this study, a framework for the longitudinal analysis of diffusion tensor imaging (DTI-based mapping was applied to the assessment of predefined white matter tracts in amyotrophic lateral sclerosis (ALS, as an example for a rapid progressive neurodegenerative disease.Methods: DTI was performed every 3 months in six patients with ALS (mean (M = 7.7; range 3 to 15 scans and in six controls (M = 3; range 2–5 scans with the identical scanning protocol, resulting in a total of 65 longitudinal DTI datasets. Fractional anisotropy (FA, mean diffusivity (MD, axonal diffusivity (AD, radial diffusivity (RD, and the ratio AD/RD were studied to analyze alterations within the corticospinal tract (CST which is a prominently affected tract structure in ALS and the tract correlating with Braak’s neuropathological stage 1. A correlation analysis was performed between progression rates based on DTI metrics and the revised ALS functional rating scale (ALS-FRS-R.Results: Patients with ALS showed an FA and AD/RD decline along the CST, while DTI metrics of controls did not change in longitudinal DTI scans. The FA and AD/RD decrease progression correlated significantly with ALS-FRS-R decrease progression.Conclusion: On the basis of the longitudinal assessment, DTI-based metrics can be considered as a possible noninvasive follow-up marker for disease progression in neurodegeneration. This finding was demonstrated here for ALS as a fast progressing neurodegenerative disease.

Longitudinal Diffusion Tensor Imaging-Based Assessment of Tract Alterations: An Application to Amyotrophic Lateral Sclerosis.

Science.gov (United States)

Baldaranov, Dobri; Khomenko, Andrei; Kobor, Ines; Bogdahn, Ulrich; Gorges, Martin; Kassubek, Jan; Müller, Hans-Peter

2017-01-01

Objective : The potential of magnetic resonance imaging (MRI) as a technical biomarker for cerebral microstructural alterations in neurodegenerative diseases is under investigation. In this study, a framework for the longitudinal analysis of diffusion tensor imaging (DTI)-based mapping was applied to the assessment of predefined white matter tracts in amyotrophic lateral sclerosis (ALS), as an example for a rapid progressive neurodegenerative disease. Methods : DTI was performed every 3 months in six patients with ALS (mean (M) = 7.7; range 3 to 15 scans) and in six controls ( M = 3; range 2-5 scans) with the identical scanning protocol, resulting in a total of 65 longitudinal DTI datasets. Fractional anisotropy (FA), mean diffusivity (MD), axonal diffusivity (AD), radial diffusivity (RD), and the ratio AD/RD were studied to analyze alterations within the corticospinal tract (CST) which is a prominently affected tract structure in ALS and the tract correlating with Braak's neuropathological stage 1. A correlation analysis was performed between progression rates based on DTI metrics and the revised ALS functional rating scale (ALS-FRS-R). Results : Patients with ALS showed an FA and AD/RD decline along the CST, while DTI metrics of controls did not change in longitudinal DTI scans. The FA and AD/RD decrease progression correlated significantly with ALS-FRS-R decrease progression. Conclusion : On the basis of the longitudinal assessment, DTI-based metrics can be considered as a possible noninvasive follow-up marker for disease progression in neurodegeneration. This finding was demonstrated here for ALS as a fast progressing neurodegenerative disease.

Heat production: Longitudinal versus torsional phacoemulsification.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-10-01

To compare the heat production of longitudinal versus torsional phacoemulsification under strict laboratory test conditions. Department of Ophthalmology, David Geffen School of Medicine at UCLA, and Jules Stein Eye Institute, Los Angeles, California, USA. Two Infiniti phacoemulsification handpieces were inserted into silicone test chambers filled with a balanced salt solution and imaged serially using a thermal camera. Incision compression was simulated by suspending 25.3 g weights from the silicone chambers. To simulate occlusion of the phacoemulsification tip, the aspiration line was clamped. Peak temperatures were measured 0, 10, 30, 60, and 120 seconds after the commencement of continuous ultrasound power. The 2 handpieces, operating exclusively in longitudinal or torsional modes, were compared 3 ways: (1) using the same power displayed on the instrument console, (2) using identical stroke lengths, and (3) using the same applied energy, a product of stroke length and frequency. For all 3 comparisons, torsional phacoemulsification resulted in lower temperatures at each time point. At the same displayed power setting, the scenario most familiar to cataract surgeons, longitudinal phacoemulsification elevated temperatures up to 41.5 degrees C more than torsional phacoemulsification. Torsional phacoemulsification generated less heat than longitudinal phacoemulsification in all 3 comparison tests. Lower operating temperatures indicate lower heat generation within the same volume of fluid, and this may provide additional thermal protection during cataract surgery.

Cross-Sectional and Longitudinal Associations between Serum Bilirubin and Prediabetes in a Health Screening Population.

Science.gov (United States)

Oda, Eiji

2016-06-01

Longitudinal associations between total bilirubin (TB) and prediabetes have not been reported. This study investigated cross-sectional and longitudinal associations between TB and prediabetes. Cross-sectional associations between TB and prediabetes were investigated in 3681 nondiabetic subjects. Longitudinal associations between TB and prediabetes over 6 years were investigated in 2149 subjects who were normoglycemic at baseline. Prediabetes was defined as fasting plasma glucose (FPG) levels of ≥5.6 mmol/L or glycated hemoglobin levels of ≥5.7% excluding diabetes. The prevalence of prediabetes was 25.4%, and the cumulative incidence of prediabetes during 6 years was 25.5% in a Japanese health screening population. Prevalent prediabetes was significantly associated with the quintiles of TB in nonsmoking men (trend, pprediabetes was not significantly associated with the quintiles of TB, while it was positively associated with 1 standard deviation increase in TB in nonsmoking men (hazard ratio [95% confidence interval]; 1.21 [1.07 to 1.37], p=0.002). TB levels were significantly inversely associated with prevalent prediabetes in nonsmokers, but not in smokers, whereas an inverse association between TB levels and incident prediabetes seemed to be unlikely. Copyright © 2016 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

Longitudinal beam instability due to the ring impedance at KEK's accelerator test facility damping ring

International Nuclear Information System (INIS)

Kim, Eun-San

2003-01-01

This paper shows the results of a numerical study of the impedance in the Accelerator Test Facility damping ring. The longitudinal impedance in the damping ring is shown to be inductive. It is shown that the total impedance |Z || /n| is 0.23 Ω and the inductance is L = 14 nH. In the extremely low emittance beam of the damping ring, bunch lengthening is caused by both the effects of potential-well distortion and intra-beam scattering. In this paper, the bunch-lengthening due to the ring impedance is numerically investigated, and the result shows qualitative agreement with the result of an analysis performed using the bunch-length measurement. With the calculated longitudinal impedance, the instability threshold in the damping ring is estimated to be a bunch population of 3.3 x 10 10 by using both a Vlasov equation approach and a multi-particle tracking method.

Longitudinal magnetoresistance and magnototermopower in Bi nanowires

International Nuclear Information System (INIS)

Para, G.

2011-01-01

Full text: The galvanomagnetic effect of single crystals Bi nanowires have been studied in longitudinal magnetic fields up to 14 T. The influence of diameters, temperature and deformation extension on the longitudinal magnetoresistance and magnetotermopower (H||I, H||ΔT) of bismuth nanowires is studied. Elastic deformation measurements were conducted at maximum relative elongation 2 %. For the first time have been investigated the magnetotermopower of Bi nanowires with d=45 nm. Essentially non monotonic dependence H max on temperature in longitudinal thermopower in wires with d=45-60 nm is found out. Such difference in behavior of maximum on R(H) and on α(H) in wires with d<100nm says that the behavior of resistance is caused by other mechanism, then thermopower. (author)

Longitudinal Electron Bunch Diagnostics Using Coherent Transition Radiation

CERN Document Server

Mihalcea, Daniel; Happek, Uwe; Regis-Guy Piot, Philippe

2005-01-01

The longitudinal charge distribution of electron bunches in the Fermilab A0 photo-injector was determined by using the coherent transition radiation produced by electrons passing through a thin metallic foil. The auto-correlation of the transition radiation signal was measured with a Michelson type interferometer. The response function of the interferometer was determined from measured and simulated power spectra for low electron bunch charge and maximum longitudinal compression. Kramers-Kroning technique was used to determine longitudinal charge distribution. Measurements were performed for electron bunch lengths in the range from 0.3 to 2 ps (rms).

Multilevel Cross-Dependent Binary Longitudinal Data

KAUST Repository

Serban, Nicoleta

2013-10-16

We provide insights into new methodology for the analysis of multilevel binary data observed longitudinally, when the repeated longitudinal measurements are correlated. The proposed model is logistic functional regression conditioned on three latent processes describing the within- and between-variability, and describing the cross-dependence of the repeated longitudinal measurements. We estimate the model components without employing mixed-effects modeling but assuming an approximation to the logistic link function. The primary objectives of this article are to highlight the challenges in the estimation of the model components, to compare two approximations to the logistic regression function, linear and exponential, and to discuss their advantages and limitations. The linear approximation is computationally efficient whereas the exponential approximation applies for rare events functional data. Our methods are inspired by and applied to a scientific experiment on spectral backscatter from long range infrared light detection and ranging (LIDAR) data. The models are general and relevant to many new binary functional data sets, with or without dependence between repeated functional measurements.

Has the inclusion of a longitudinally integrated communication skills program improved consultation skills in medical students? A pilot study

Directory of Open Access Journals (Sweden)

Sameena Shah

2016-01-01

Full Text Available Background: Evidence highlights a lack of communication skills in doctors leading to dysfunctional consultations. To address this deficit, a private medical college instituted curricular reforms with inclusion of a longitudinal communication skills program. A pilot study was undertaken to evaluate the effectiveness of this program by comparing the consultation skills of medical students of this college with a medical college without a communication skills program. Methods: A 4-station Objective Structured Clinical Examination (OSCE was conducted in the third and final year. Mann-Whitney U-test was used to compare the difference in the distribution between OSCE stations total and construct scores. Results: At the end of the third year, 21 (31.34%, students of the study site (medical college 1 [college with integrated longitudinal communication skills program] and 31 (46.26% students from the comparison site (medical college 2 [comparable college without communication skills program] consented. Medical college 1 achieved a significantly higher overall mean total station score of 68.0% (standard deviation [SD] =13.5 versus 57.2% (SD = 15.4 (P < 0.001. Significantly higher mean scores were achieved on three stations. At the end of the final year, 19 students (29.3% from medical college 1 and 22 (34% students from medical college 2 consented. The difference in overall mean total station score reduced from 9.2% to 7.1% (70.2 (SD = 13.7 versus 63.1 (SD = 15.2 (P = 0.004. The mean scores of both colleges decreased in "Patient presenting with Hepatitis C Report" station (P values 0.004 and 0.775 and in "Patient Request for Faith Healing Therapy in Diabetes Mellitus" station (P values 0.0046 and 0.036, respectively. Conclusion: Longitudinal communication skills in an undergraduate curriculum positively impacted consultation skills. Community-based training and faculty development are required to develop effective patient-centered consultation skills.

Patient safety in the clinical laboratory: a longitudinal analysis of specimen identification errors.

Science.gov (United States)

Wagar, Elizabeth A; Tamashiro, Lorraine; Yasin, Bushra; Hilborne, Lee; Bruckner, David A

2006-11-01

Patient safety is an increasingly visible and important mission for clinical laboratories. Attention to improving processes related to patient identification and specimen labeling is being paid by accreditation and regulatory organizations because errors in these areas that jeopardize patient safety are common and avoidable through improvement in the total testing process. To assess patient identification and specimen labeling improvement after multiple implementation projects using longitudinal statistical tools. Specimen errors were categorized by a multidisciplinary health care team. Patient identification errors were grouped into 3 categories: (1) specimen/requisition mismatch, (2) unlabeled specimens, and (3) mislabeled specimens. Specimens with these types of identification errors were compared preimplementation and postimplementation for 3 patient safety projects: (1) reorganization of phlebotomy (4 months); (2) introduction of an electronic event reporting system (10 months); and (3) activation of an automated processing system (14 months) for a 24-month period, using trend analysis and Student t test statistics. Of 16,632 total specimen errors, mislabeled specimens, requisition mismatches, and unlabeled specimens represented 1.0%, 6.3%, and 4.6% of errors, respectively. Student t test showed a significant decrease in the most serious error, mislabeled specimens (P patient safety projects. Trend analysis demonstrated decreases in all 3 error types for 26 months. Applying performance-improvement strategies that focus longitudinally on specimen labeling errors can significantly reduce errors, therefore improving patient safety. This is an important area in which laboratory professionals, working in interdisciplinary teams, can improve safety and outcomes of care.

Beating the Odds: A Longitudinal Investigation of Low-Income Dual-Language and Monolingual Children's English Language and Literacy Performance

Science.gov (United States)

Han, Myae; Vukelich, Carol; Buell, Martha; Meacham, Sohyun

2014-01-01

Research Findings: The current study reports on the results of a longitudinal investigation of the language and early literacy development of a sample of dual-language learners (DLLs) and monolingual English speakers from low-income families who received an Early Reading First intervention during their Head Start preschool year. A total of 62…

The optimization of longitudinal convective fins with internal heat generation

International Nuclear Information System (INIS)

Razelos, P.

1979-01-01

The solution of the optimization problem for longitudinal convective fins of constant thickness, triangular or parabolic profile, and uniform internal heat generation, is presented. The cases considered are those of a given heat generation density, total heat generation and heat generation per unit width of the fin, when either the heat dissipation or the width of the fin is prescribed. The results are set forth in a nondimensional form, which are presented graphically. The effect of the fin's thermal conductivity upon the optimum dimensions is discussed, and limiting values for the heat generation and the heat dissipation, which may be imposed on the fin for a feasible optimization, are also obtained. (Auth.)

FISH DIVERSITY ALONG THE LONGITUDINAL GRADIENT IN A MAN–MADE LAKE OF WEST AFRICA, TAABO HYDROELECTRIC RESERVOIR, IVORY COAST

Directory of Open Access Journals (Sweden)

N. G. Aliko

2010-04-01

Full Text Available Fish assemblage patterns in Taabo Reservoir, a hydroelectric lake of Ivory Coast, were studied and related to the longitudinal gradient (river–dam gradient composed of riverine, transitional, and lacustrine zones. Data were collected at 5 stations and each one was sampled during 5 surveys. Fish community structure was analysed using alpha and beta diversity indices. In total, 53 fish species were obtained in the whole ecosystem. Total species richness recorded at each ecological zone was 42, 43 and 45 species respectively in the riverine, transitional and lacustrine zones. Alpha diversity did not differed significantly along the longitudinal gradient but reached the highest value (33 species in the transitional zone and the lowest (18 species occurred in both the riverine and lacustrine zones. Temporal variability of Alpha diversity according to the hydrological regime of the lake differed with the zone. Beta diversity showed that fish assemblages similarity was higher between the transitional and the riverine zones (βw = 0.43 and lower between the riverine and the lacustrine zones (βw = 0.79.

Fingerprints of transverse and longitudinal coupling between induced open quantum dots in the longitudinal magnetoconductance through antidot lattices

Science.gov (United States)

Ujevic, Sebastian; Mendoza, Michel

2010-07-01

We propose numerical simulations of longitudinal magnetoconductance through a finite antidot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magnetoconductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magnetoconductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the antidot lattice. A relationship is observed between the distribution of antidots and the formed conductance bands, allowing a systematic follow up of the bands as a function of the applied magnetic field and quantum point-contact width. We observed a high conductance intensity [between n and (n+1) quantum of conductance, n=1,2,… ] in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the antidots potential and the quantum point-contact width. A new continuous channel (not expected) is induced by the variation in the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field.

Combining near-subject absolute and relative measures of longitudinal hydration in hemodialysis.

Science.gov (United States)

Chan, Cian; McIntyre, Christopher; Smith, David; Spanel, Patrik; Davies, Simon J

2009-11-01

The feasibility and additional value of combining bioimpedance analysis (BIA) with near-subject absolute measurement of total body water using deuterium dilution (TBW(D)) in determining longitudinal fluid status was investigated. Fifty-nine hemodialysis patients (17 female; age 58.4 +/- 16.1 yr; body mass index 27.0 +/- 5.4) were enrolled into a 12-mo, two-center, prospective cohort study. Deuterium concentration was measured in breath by flowing-afterglow mass spectrometry using a validated protocol ensuring full equilibration with the TBW; BIA was measured using a multifrequency, multisegmental device. Comorbidity was quantified by the Stoke score. Clinicians were blinded to body composition data. At baseline and 12 mo, there was an incremental discrepancy between TBW(BIA) and TBW(D) volumes such that greater comorbidity was associated with increasing overhydration. Forty-three patients who completed the study had no longitudinal differences in the prescribed or achieved postdialysis weights. In contrast, TBW(D) increased without a change in TBW(BIA) (mean difference -0.10 L). Changes in TBW and lean body mass differed according to baseline comorbidity; without comorbidity, BIA also identified an increase in TBW and lean body mass, whereas with increasing comorbid burden, BIA failed to demonstrate increases in tissue hydration identified by TBW(D). Combined near-patient measurements of absolute and BIA-estimated TBW are achievable in a dialysis facility by identifying changes in body composition not fully appreciated by routine assessment. BIA underestimates tissue overhydration that is associated with comorbidity, resulting in reduced sensitivity to longitudinal increases during a 12-mo period.

Longitudinal analysis of progression in glaucoma using spectral-domain optical coherence tomography.

Science.gov (United States)

Wessel, Julia M; Horn, Folkert K; Tornow, Ralf P; Schmid, Matthias; Mardin, Christian Y; Kruse, Friedrich E; Juenemann, Anselm G; Laemmer, Robert

2013-05-01

To compare the longitudinal loss of RNFL thickness measurements by SD-OCT in healthy individuals and glaucoma patients with or without progression concerning optic disc morphology. A total of 62 eyes, comprising 38 glaucomatous eyes with open angle glaucoma and 24 healthy controls, were included in the study (Erlangen Glaucoma Registry, NTC00494923). All patients were investigated annually over a period of 3 years by Spectralis SD-OCT measuring peripapillary RNFL thickness. By masked comparative analysis of photographs, the eyes were classified into nonprogressive and progressive glaucoma cases. Longitudinal loss of RNFL thickness was compared with morphological changes of optic disc morphology. Mixed model analysis of annual OCT scans revealed an estimated annual decrease of the RNFL thickness by 2.12 μm in glaucoma eyes with progression, whereas glaucoma eyes without progression in optic disc morphology lost 1.18 μm per year in RNFL thickness (P = 0.002). The rate of change in healthy eyes was 0.60 μm and thereby also significantly lower than in glaucoma eyes with progression (P < 0.001). The intrasession variability of three successive measurements without head repositioning was 1.5 ± 0.7 μm. The loss of mean RNFL thickness exceeded the intrasession variability in 60% of nonprogressive eyes, and in 85% of progressive eyes after 3 years. LONGITUDINAL MEASUREMENTS OF RNFL THICKNESS USING SD-OCT SHOW A MORE PRONOUNCED REDUCTION OF RNFL THICKNESS IN PATIENTS WITH PROGRESSION COMPARED WITH PATIENTS WITHOUT PROGRESSION IN GLAUCOMATOUS OPTIC DISC CHANGES. (www.clinicaltrials.gov number, NTC00494923.).

Longitudinal data analysis a handbook of modern statistical methods

CERN Document Server

Fitzmaurice, Garrett; Verbeke, Geert; Molenberghs, Geert

2008-01-01

Although many books currently available describe statistical models and methods for analyzing longitudinal data, they do not highlight connections between various research threads in the statistical literature. Responding to this void, Longitudinal Data Analysis provides a clear, comprehensive, and unified overview of state-of-the-art theory and applications. It also focuses on the assorted challenges that arise in analyzing longitudinal data. After discussing historical aspects, leading researchers explore four broad themes: parametric modeling, nonparametric and semiparametric methods, joint

Variable selection and estimation for longitudinal survey data

KAUST Repository

Wang, Li

2014-09-01

There is wide interest in studying longitudinal surveys where sample subjects are observed successively over time. Longitudinal surveys have been used in many areas today, for example, in the health and social sciences, to explore relationships or to identify significant variables in regression settings. This paper develops a general strategy for the model selection problem in longitudinal sample surveys. A survey weighted penalized estimating equation approach is proposed to select significant variables and estimate the coefficients simultaneously. The proposed estimators are design consistent and perform as well as the oracle procedure when the correct submodel was known. The estimating function bootstrap is applied to obtain the standard errors of the estimated parameters with good accuracy. A fast and efficient variable selection algorithm is developed to identify significant variables for complex longitudinal survey data. Simulated examples are illustrated to show the usefulness of the proposed methodology under various model settings and sampling designs. © 2014 Elsevier Inc.

Fatness predicts decreased physical activity and increased sedentary time, but not vice versa: support from a longitudinal study in 8- to 11-year-old children

DEFF Research Database (Denmark)

Hjorth, M. F.; Chaput, J.-P.; Ritz, C.

2014-01-01

and FMI. Methods: Cross-sectional and longitudinal analyses were done using data from the OPUS school meal study on 785 children (52% boys, 13.4% overweight, ages 8–11 years). Total PA, moderate-to-vigorous PA (MVPA), sedentary time and sleep duration (7 days and 8 nights) were assessed......Objective: To examine independent and combined cross-sectional associations between movement behaviors (physical activity (PA), sedentary time, sleep duration, screen time and sleep disturbance) and fat mass index (FMI), as well as to examine longitudinal associations between movement behaviors...... by an accelerometer and FMI was determined by dual-energy X-ray absorptiometry (DXA) on three occasions over 200 days. Demographic characteristics, screen time and sleep disturbance (Children’s Sleep Habits Questionnaire) were also obtained. Results: Total PA, MVPA and sleep duration were negatively associated...

Magnetic field of longitudinal gradient bend

Science.gov (United States)

Aiba, Masamitsu; Böge, Michael; Ehrlichman, Michael; Streun, Andreas

2018-06-01

The longitudinal gradient bend is an effective method for reducing the natural emittance in light sources. It is, however, not a common element. We have analyzed its magnetic field and derived a set of formulae. Based on the derivation, we discuss how to model the longitudinal gradient bend in accelerator codes that are used for designing electron storage rings. Strengths of multipole components can also be evaluated from the formulae, and we investigate the impact of higher order multipole components in a very low emittance lattice.

Longitudinal anthropometric assessment of infants born to HIV-1-infected mothers, Belo Horizonte, Southeastern Brazil Evaluación antropométrica longitudinal de lactantes nacidos de madres infectadas por VIH-1 Avaliação antropométrica longitudinal de lactentes nascidos de mães infectadas pelo HIV-1

OpenAIRE

Maria Arlene Fausto; Mariângela Carneiro; Carlos Maurício F Antunes; Enrico Antonio Colosimo; Jorge Andrade Pinto

2011-01-01

OBJECTIVE: To evaluate the growth parameters in infants who were born to HIV-1-infected mothers. METHODS: The study was a longitudinal evaluation of the z-scores for the weight-for-age (WAZ), weight-for-length (WLZ) and length-for-age (LAZ) data collected from a cohort. A total of 97 non-infected and 33 HIV-infected infants born to HIV-1-infected mothers in Belo Horizonte, Southeastern Brazil, between 1995 and 2003 was studied. The average follow-up period for the infected and non-infected ch...

Quantum Interference in the Longitudinal Oscillations of the Total Spin of a Dimeric Molecular Nanomagnet

Science.gov (United States)

Ramsey, Christopher; Del Barco, Enrique; Hill, Stephen; Shah, Sonali; Beedle, Christopher; Hendrickson, David

2008-03-01

The synthetic flexibility of molecular magnets allows one to systematically produce samples with desirable properties such as those with entangled spin states for implementation in quantum logic gates. Here we report direct evidence of quantum oscillations of the total spin length of a dimeric molecular nanomagnet through the observation of quantum interference associated with tunneling trajectories between states having different spin quantum numbers. As we outline, this is a consequence of the unique characteristics of a molecular Mn12 wheel which behaves as a (weak) ferromagnetic exchange-coupled molecular dimer: each half of the molecule acts as a single-molecule magnet (SMM), while the weak coupling between the two halves gives rise to an additional internal spin degree of freedom within the molecule, namely that its total spin may fluctuate. This extra degree of freedom accounts for several magnetization tunneling resonances that cannot be explained within the usual giant spin approximation. More importantly, the observation of quantum interference provides unambiguous evidence for the quantum mechanical superposition involving entangled states of both halves of the wheel.

Symptoms of mothers and infants related to total volatile organic compounds in household products

OpenAIRE

Farrow, A; Taylor, H; Northstone, K; Golding, J

2003-01-01

The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that ...

First measurement of charged current cross sections at HERA with longitudinally polarised positrons

Science.gov (United States)

H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sedlák, K.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2006-03-01

Data taken with positrons of different longitudinal polarisation states in collision with unpolarised protons at HERA are used to measure the total cross sections of the charged current process, ep→ν¯X, for negative four-momentum transfer squared Q>400 GeV and inelasticity y<0.9. Together with the corresponding cross section obtained from the previously published unpolarised data, the polarisation dependence of the charged current cross section is measured for the first time at high Q and found to be in agreement with the Standard Model prediction.

Worse and Worse and Worse: Essential Tremor Patients’ Longitudinal Perspectives on their Condition

Directory of Open Access Journals (Sweden)

Jesus Gutierrez

2016-10-01

Full Text Available Background: Essential tremor (ET patients regularly inquire about their prognosis. Therefore, physicians have cause to review available medical literature for meaningful answers. Longitudinal studies are ideally suited to provide a glimpse into the evolution of tremor. Despite its high prevalence, there are surprisingly few longitudinal clinical studies of ET. Furthermore, none of them provided data from the patients’ perspective. Understanding the patient vantage point is valuable as it is the starting point of personalized medicine. Given the progressive nature of ET, we hypothesized that many patients will experience an increase in symptom severity over time. However, due to a lack of clinical data, the exact nature of this progression is unclear. For example, whether patients experience a worsening at each time interval is simply not known. In this longitudinal study, we assessed whether ET patients felt that their symptoms had worsened between each follow-up evaluation and try to identify specific clinical characteristics associated with this experience.Methods: A cohort of 164 ET cases enrolled in a prospective, longitudinal research study. After a baseline in-person assessment, they received regular telephone evaluations for up to 5.25 years, beginning in 2009. During each follow-up evaluation, cases answered the question, has your ET worsened since our last call? Results: Two-thirds (104 63.4% of ET cases reported worsening at one-half or more of their follow-up evaluations. Furthermore, one-in-four cases (44 26.8% reported worsening at every follow-up evaluation. Self-reported worsening was not associated with any of the baseline clinical variables assessed, including age, gender, tremor duration, age at tremor onset, or total tremor score. Conclusions: Little has been written from the patient perspective on progression of ET. When followed longitudinally at regular intervals, a majority of ET cases we studied reported worsening one

Progressive changes in arch width from primary to early mixed dentition period: A longitudinal study

OpenAIRE

S Sangwan; H S Chawla; A Goyal; K Gauba; U Mohanty

2011-01-01

Objective: The present study was conducted to evaluate, on a longitudinal basis, the changes in intercanine and intermolar widths form the primary to the early mixed dentition periods. Materials and Methods: A total of 38 children aged 4-5 years, with normal occlusion without any proximal caries or any dental anomalies, were selected. The impressions were recorded and casts were prepared. Intercanine and intermolar widths were measured on these dental casts with the help of a digital vernier ...

Longitudinal associations of nursing staff turnover with patient outcomes in long-term care hospitals in Korea.

Science.gov (United States)

Kim, Yoonseo; Han, Kihye

2018-01-10

To describe the characteristics of long-term care hospitals in 2010-2013 and to examine the longitudinal associations of nursing staff turnover with patient outcomes. The number of long-term care hospitals has exploded in Korea since the national long-term care insurance was launched in 2008. The care quality deviation across long-term care hospitals is large. This was a longitudinal secondary data analysis using the Health Insurance Review and Assessment Service's data. From 2010 to 2013, the nursing staff turnover rate decreased. The number of patients per registered nurse increased while that per total nursing staff and skill mix decreased. All adverse patient outcomes decreased. Higher nursing staff turnover and lower RN proportions were associated with adverse patient outcomes. Since the launch of the long-term care insurance, total nursing staffing, turnover rate and patient outcomes have improved, while the skill mix has decreased. Systematic efforts to decrease nursing staff turnover should be implemented for better long-term care patient outcomes. In addition to maintaining high levels of nurse staffing and skill mix, supportive work environments and competitive wages and benefits could reduce turnover, and ultimately adverse patient outcomes. Health care policy should separate nursing staffing levels for registered nurses and certified nursing assistants. © 2018 John Wiley & Sons Ltd.

Dynamics of a longitudinal current during a magnetic storm

International Nuclear Information System (INIS)

Dolginov, S.Sh.; Zhuzgov, L.N.; Kosacheva, V.P.; Strunnikova, L.N.; Tyurmina, L.O.; Sharova, V.A.; Shkol'nikova, S.I.

1984-01-01

Results, investigating a spatial distribution and the structure of longitudinal currents during a magnetic storm at 18-19.09.81, are presented. It is shown that during the main phase of the storm the large-scale current system expands to the equator, and current density increases. Inside the current layer and to the pole of it there appears intensive small scale longitudinal l currents. During magnetic storm restopation phase the current system segregates into several pairs of opposite directed currents. During further decreasing of geomagnetic activity the large-scale current system is restored+ and its center is shifted to the pole, longitudinal current density being decreased. The invariant width of longitudinal currents is decreased, while the magnitude, Dsub(st), being increased, that is connected to the displacement of an auroral oval to the equator

Multi-longitudinal-mode micro-laser model

Science.gov (United States)

Staliunas, Kestutis

2017-10-01

We derive a convenient model for broad aperture micro-lasers, such as microchip lasers, broad area semiconductor lasers, or VCSELs, taking into account several longitudinal mode families. We provide linear stability analysis, and show characteristic spatio-temporal dynamics in such multi-longitudinal mode laser models. Moreover, we derive the coupled mode model in the presence of intracavity refraction index modulation (intracavity photonic crystal). Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.

Second- to third-trimester longitudinal growth assessment for prediction of small-for-gestational age and late fetal growth restriction.

Science.gov (United States)

Caradeux, J; Eixarch, E; Mazarico, E; Basuki, T R; Gratacós, E; Figueras, F

2018-02-01

Detection of fetal growth restriction (FGR) remains poor and most screening strategies rely on cross-sectional evaluation of fetal size during the third trimester. A longitudinal and individualized approach has been proposed as an alternative method of evaluation. The aim of this study was to compare second- to third-trimester longitudinal growth assessment to cross-sectional evaluation in the third trimester for the prediction of small-for-gestational age (SGA) and late FGR in low-risk singleton pregnancy. This was a prospective cohort study of 2696 unselected consecutive low-risk singleton pregnancies scanned at 21 ± 2 and 32 ± 2 weeks. For cross-sectional growth assessment, abdominal circumference (AC) measurements were transformed to z-values according the 21st-INTERGROWTH standards. Longitudinal growth assessment was performed by calculating the AC z-velocity and the second- to third-trimester AC conditional growth centile. Longitudinal assessment was compared with cross-sectional assessment at 32 weeks. Association of cross-sectional and longitudinal evaluations with SGA and late FGR was assessed by logistic regression analysis. Predictive performance was determined by receiver-operating characteristics curve analysis. In total, 210 (7.8%) newborns were classified as SGA and 103 (3.8%) as late FGR. Neither longitudinal measurement improved the association with SGA or late FGR provided by cross-sectional evaluation of AC z-score at 32 weeks. Areas under the curves of AC z-velocity and conditional AC growth were significantly smaller than those of cross-sectional AC z-scores (P third trimester has a low predictive capacity for SGA and late FGR in low-risk singleton pregnancy compared with cross-sectional growth evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal Control for Mengshi Autonomous Vehicle via Gauss Cloud Model

Directory of Open Access Journals (Sweden)

Hongbo Gao

2017-12-01

Full Text Available Dynamic robustness and stability control is a requirement for self-driving of autonomous vehicle. Longitudinal control technique of autonomous vehicle is basic theory and one key complex technique which must have the reliability and precision of vehicle controller. The longitudinal control technique is one of the foundations of the safety and stability of autonomous vehicle control. In our paper, we present a longitudinal control algorithm based on cloud model for Mengshi autonomous vehicle to ensure the dynamic stability and tracking performance of Mengshi autonomous vehicle. The longitudinal control algorithm mainly uses cloud model generator to control the acceleration of the autonomous vehicle to achieve the goal that controls the speed of Mengshi autonomous vehicle. The proposed longitudinal control algorithm based on cloud model is verified by real experiments on Highway driving scene. The experiments results of the acceleration and speed show that the algorithm is validity and stability.

Parameterized Linear Longitudinal Airship Model

Science.gov (United States)

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

Bayesian Nonparametric Longitudinal Data Analysis.

Science.gov (United States)

Quintana, Fernando A; Johnson, Wesley O; Waetjen, Elaine; Gold, Ellen

2016-01-01

Practical Bayesian nonparametric methods have been developed across a wide variety of contexts. Here, we develop a novel statistical model that generalizes standard mixed models for longitudinal data that include flexible mean functions as well as combined compound symmetry (CS) and autoregressive (AR) covariance structures. AR structure is often specified through the use of a Gaussian process (GP) with covariance functions that allow longitudinal data to be more correlated if they are observed closer in time than if they are observed farther apart. We allow for AR structure by considering a broader class of models that incorporates a Dirichlet Process Mixture (DPM) over the covariance parameters of the GP. We are able to take advantage of modern Bayesian statistical methods in making full predictive inferences and about characteristics of longitudinal profiles and their differences across covariate combinations. We also take advantage of the generality of our model, which provides for estimation of a variety of covariance structures. We observe that models that fail to incorporate CS or AR structure can result in very poor estimation of a covariance or correlation matrix. In our illustration using hormone data observed on women through the menopausal transition, biology dictates the use of a generalized family of sigmoid functions as a model for time trends across subpopulation categories.

A single hole tracer test to determine longitudinal dispersion

International Nuclear Information System (INIS)

Noy, D.J.; Holmes, D.C.

1986-03-01

The paper concerns a single hole tracer test to determine longitudinal dispersion, which is an important parameter in assessing the suitability of a site for radioactive waste disposal. The theory, equipment and procedure for measuring longitudinal dispersion in a single borehole is described. Results are presented for field trials conducted in an aquifer, where the technique produced good results. The measured value of longitudinal dispersion, from a single hole test, relates only to a limited volume of rock immediately adjacent to the borehole. (U.K.)

Longitudinal forces acting at side-to-end and end-to-side anastomoses when a knitted polyester arterial prosthesis is implanted in the dog.

Science.gov (United States)

Dadgar, L; Downs, A R; Deng, X; Marois, Y; King, M W; Martin, L; Guidoin, R

1995-01-01

In a previous study, which investigated the tensions at the proximal and distal end-to-end anastomoses of a vascular prosthesis, no significant differences were found in the longitudinal forces between the two anastomotic sites after different periods of implantation. The present follow-up study was devised to study the longitudinal forces at a proximal side-to-end and a distal end-to-side anastomosis using a warp knitted polyester prosthesis implanted as a canine thorocoabdominal bypass. The external surface of the prosthesis contained a specially printed "tension indicator" design, which enabled changes in length to be assessed photographically at the two anastomoses at the time of implantation and at sacrifice. The longitudinal force at each site was then calculated using a relationship obtained experimentally between the total longitudinal force and the changes in length of the virgin graft in vitro. The in vitro measurements on the prosthesis were performed using a computer-controlled laser calibration system. Although the results showed a tendency toward a gradual loss in longitudinal force at both anastomoses over 7 months in situ, statistical analysis showed no significant difference in the longitudinal force at the two anastomotic sites after any period of implantation. Histopathological and textile analysis also showed that the characteristics of the prostheses were similar at both anastomotic sites. This does not mean, however, that the intramural stress concentrations experienced by the two sites were the same. While comparing the level of the longitudinal forces measured in this study with those observed in the previous thoracic aorta study using end-to-end anastomoses, no significant differences were observed due to the different types of anastomoses. It would appear that the longitudinal force is not one of the main etiological factors that cause the formation and localization of anastomotic failure.

Explaining the increasing heritability of cognitive ability across development: a meta-analysis of longitudinal twin and adoption studies.

Science.gov (United States)

Briley, Daniel A; Tucker-Drob, Elliot M

2013-09-01

Genes account for increasing proportions of variation in cognitive ability across development, but the mechanisms underlying these increases remain unclear. We conducted a meta-analysis of longitudinal behavioral genetic studies spanning infancy to adolescence. We identified relevant data from 16 articles with 11 unique samples containing a total of 11,500 twin and sibling pairs who were all reared together and measured at least twice between the ages of 6 months and 18 years. Longitudinal behavioral genetic models were used to estimate the extent to which early genetic influences on cognition were amplified over time and the extent to which innovative genetic influences arose with time. Results indicated that in early childhood, innovative genetic influences predominate but that innovation quickly diminishes, and amplified influences account for increasing heritability following age 8 years.

Assessment of pituitary adenoma volumetric change using longitudinal MR image registration

Energy Technology Data Exchange (ETDEWEB)

Ringstad, Geir Andre; Hald, John K. [Oslo University Hospital-Rikshospitalet, Clinic for Imaging and Intervention, Oslo (Norway); Emblem, Kyrre Eeg [Oslo University Hospital-Rikshospitalet, Department of Medical Physics, Oslo (Norway); Oslo University Hospital-Rikshospitalet, The Interventional Centre, Oslo (Norway); Holland, Dominic [University of California, Department of Neurosciences, San Diego, CA (United States); Dale, Anders M. [University of California, Department of Neurosciences, San Diego, CA (United States); University of California, Department of Radiology, San Diego, CA (United States); Bjornerud, Atle [Oslo University Hospital-Rikshospitalet, Department of Medical Physics, Oslo (Norway); University of Oslo, Department of Physics, Oslo (Norway)

2012-05-15

Change detection is a crucial factor in monitoring of slowly evolving pathologies. The objective of the study was to test a semi-automatic method applied on longitudinal MRI monitoring of volume change in pituitary macroadenomas. The proposed method is based on a visual comparison of geometrically corrected, co-registered, intensity-normalized contrast-enhanced (CE) 3D GRE T1-weighted images. Qualitative volume changes based on this applied method were compared with experts' readings of conventional pre- and post-CE 2D T1-weighted images. Magnetic resonance (MR) imaging was performed two to four times in 13 patients with a total combination of 29 time points. Compared to conventional 2D MR readings, a diagnosis of tumor growth (yes/no) was changed in 5 of 13 patients (38%) at 9 of the 29 combinations of time points (31%) using the 3D-based semi-automatic method. With manual tumor tracings as reference, McNemar's test showed a significant difference between the two methods. Visual comparison of geometrically corrected, intensity-normalized, and affine-aligned longitudinal 3D images may enable more accurate assessment of qualitative volumetric change in pituitary adenomas than conventional reading of 2D images. (orig.)

Longitudinal variability of time-location/activity patterns of population at different ages: a longitudinal study in California

Directory of Open Access Journals (Sweden)

Cassady Diana L

2011-09-01

Full Text Available Abstract Background Longitudinal time-activity data are important for exposure modeling, since the extent to which short-term time-activity data represent long-term activity patterns is not well understood. This study was designed to evaluate longitudinal variations in human time-activity patterns. Method We report on 24-hour recall diaries and questionnaires collected via the internet from 151 parents of young children (mostly under age 55, and from 55 older adults of ages 55 and older, for both a weekday and a weekend day every three months over an 18-month period. Parents also provided data for their children. The self-administrated diary and questionnaire distinguished ~30 frequently visited microenvironments and ~20 activities which we selected to represent opportunities for exposure to toxic environmental compounds. Due to the non-normal distribution of time-location/activity data, we employed generalized linear mixed-distribution mixed-effect models to examine intra- and inter-individual variations. Here we describe variation in the likelihood of and time spent engaging in an activity or being in a microenvironment by age group, day-type (weekday/weekend, season (warm/cool, sex, employment status, and over the follow-up period. Results As expected, day-type and season influence time spent in many location and activity categories. Longitudinal changes were also observed, e.g., young children slept less with increasing follow-up, transit time increased, and time spent on working and shopping decreased during the study, possibly related to human physiological changes with age and changes in macro-economic factors such as gas prices and the economic recession. Conclusions This study provides valuable new information about time-activity assessed longitudinally in three major age groups and greatly expands our knowledge about intra- and inter-individual variations in time-location/activity patterns. Longitudinal variations beyond weekly and

Longitudinal changes in total brain volume in schizophrenia: relation to symptom severity, cognition and antipsychotic medication.

Directory of Open Access Journals (Sweden)

Juha Veijola

Full Text Available Studies show evidence of longitudinal brain volume decreases in schizophrenia. We studied brain volume changes and their relation to symptom severity, level of function, cognition, and antipsychotic medication in participants with schizophrenia and control participants from a general population based birth cohort sample in a relatively long follow-up period of almost a decade. All members of the Northern Finland Birth Cohort 1966 with any psychotic disorder and a random sample not having psychosis were invited for a MRI brain scan, and clinical and cognitive assessment during 1999-2001 at the age of 33-35 years. A follow-up was conducted 9 years later during 2008-2010. Brain scans at both time points were obtained from 33 participants with schizophrenia and 71 control participants. Regression models were used to examine whether brain volume changes predicted clinical and cognitive changes over time, and whether antipsychotic medication predicted brain volume changes. The mean annual whole brain volume reduction was 0.69% in schizophrenia, and 0.49% in controls (p = 0.003, adjusted for gender, educational level, alcohol use and weight gain. The brain volume reduction in schizophrenia patients was found especially in the temporal lobe and periventricular area. Symptom severity, functioning level, and decline in cognition were not associated with brain volume reduction in schizophrenia. The amount of antipsychotic medication (dose years of equivalent to 100 mg daily chlorpromazine over the follow-up period predicted brain volume loss (p = 0.003 adjusted for symptom level, alcohol use and weight gain. In this population based sample, brain volume reduction continues in schizophrenia patients after the onset of illness, and antipsychotic medications may contribute to these reductions.

Nonlinear longitudinal dynamics studies at the ALS

International Nuclear Information System (INIS)

Byrd, J.M.; Cheng, W.-H.; De Santis, S.; Li, D.; Stupakov, G.; Zimmermann, F.

1999-01-01

We present a summary of results for a variety of studies of nonlinear longitudinal dynamics in the Advanced Light Source, an electron storage ring. These include observation of decoherence at injection, decay of an injected beam, forced synchrotron oscillations and diffusion from one bunch to the next. All of the measurements were made using a dual-scan streak camera which allowed the real-time observation of the longitudinal distribution of the electron beam

A Longitudinal Examination of Childhood Maltreatment and Adolescent Obesity: Results from the National Longitudinal Study of Adolescent Health (AddHealth) Study

Science.gov (United States)

Shin, Sunny Hyucksun; Miller, Daniel P.

2012-01-01

Objectives: We sought to explore the association between childhood maltreatment (e.g., neglect, physical and sexual abuse) and longitudinal growth trajectories of body mass index (BMI) from adolescence to young adulthood. Methods: We used latent curve modeling to examine data from the National Longitudinal Study of Adolescent Health (N = 8,471),…

Signal processing for longitudinal parameters of the Tevatron beam

International Nuclear Information System (INIS)

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

2005-01-01

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

Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

Science.gov (United States)

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.

Physics and technology of tunable pulsed single longitudinal mode ...

Indian Academy of Sciences (India)

precious materials. In particular, single-longitudinal mode dye lasers are useful ... to the longitudinal mode spacing of 10 GHz. Grating of 3300 .... the band of wavelength covering 3 pm and SLM operation was shown in the band of 0.5 pm.

Longitudinal changes in white matter microstructure after heavy cannabis use

Directory of Open Access Journals (Sweden)

Mary P. Becker

2015-12-01

Full Text Available 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.

The effect of longitudinal fluctuations in (3+1)D viscous hydrodynamics

Energy Technology Data Exchange (ETDEWEB)

Pang, Long-Gang; Karpenko, Yuri [FIAS, Frankfurt (Germany); Petersen, Hannah [FIAS, Frankfurt (Germany); ITP, Goethe University, Frankfurt (Germany); GSI, Darmstadt (Germany); Huovinen, Pasi [ITP, University of Wroclaw (Poland); Wang, Xin-Nian [CCNU, Wuhan (China); LBNL, Berkeley (United States)

2016-07-01

The energy density fluctuations of the quark gluon plasma (QGP) in the transverse plane are studied in detail and found to be important to explain the high order harmonic flow v{sub n} at RHIC and LHC. However, the energy density fluctuations along longitudinal direction (space-time rapidity η{sub s}) have not been fully investigated yet, even though they should exist as well. Previous studies show that the longitudinal fluctuations strongly depend on the initial entropy deposition mechanisms. In this work AMPT initial conditions are used where HIJING introduces longitudinal fluctuations originating from the asymmetry between forward and backward going participants, string length fluctuations and finite number of partons at different collision energies. The longitudinal fluctuations have been found to be responsible for the de-correlation of anisotropic flow and twist of event planes along rapidity. We study the effect of longitudinal fluctuations on the QGP expansion in both transverse and longitudinal direction within CLVisc, a (3+1)D viscous hydrodynamic code parallelized on GPU using OpenCL, to check whether the anisotropic flow is affected by longitudinal fluctuations and to determine appropriate shear viscosity over entropy density coefficients η/s in comparison with experiments at RHIC and LHC.

Longitudinal and transverse wake potentials in SLAC

International Nuclear Information System (INIS)

Bane, K.; Wilson, P.

1980-01-01

In a machine with short bunches of high peak currents, such as the SLAC collider, one needs to know the longitudinal wake potential, for the higher mode losses, and the transverse wake potential, since, for bunches passing slightly off axis, the induced transverse forces will tend to cause beam break up. The longitudinal and transverse wakes of the SLAC structure presented here, were calculated by computer using the modal method, and including an analytic extension for higher modes. (Auth.)

Longitudinal changes in visceral and subcutaneous adipose tissue and metabolic syndrome: Results from the Multicultural Community Health Assessment Trial (M-CHAT).

Science.gov (United States)

Tu, Andrew W; Humphries, Karin H; Lear, Scott A

2017-12-01

Few studies have examined whether longitudinal changes in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), independent of each other, are associated with the risk of developing metabolic syndrome (MetS). The objective of this study was to examine the longitudinal effects of VAT and SAT on MetS and metabolic risk factors in a multi-ethnic sample of Canadians followed for 5-years. In total, 598 adults of the Multicultural Community Health Assessment Trial (M-CHAT) were included in this study. Assessments of body composition using computed tomography (CT) and metabolic risk factors were conducted at baseline, 3-, and 5-years. Mixed-effects logistic regression was used to model the longitudinal effects of VAT and SAT on MetS and metabolic risk factors. There were significant between-person (cross-sectional) effects such that for every 10cm 2 higher VAT, the odds of MetS, high-risk fasting glucose levels and high-risk HDL-C levels significantly increased by 16% (95% CI: 9-24%), 11% (3-20%), and 7% (0-14%) respectively. Significant within-person (longitudinal) effects were also found such that for every 10cm 2 increase in VAT the odds of MetS and high-risk triglyceride levels significantly increased by 23% (9-39%) and 30% (14-48%), respectively. Cross-sectional or longitudinal changes in SAT were not associated with MetS or metabolic risk factors. This study found a direct relationship between longitudinal change in VAT and MetS risk independent of changes in SAT. Clinical practice should focus on the reduction of VAT to improve cardiovascular health outcomes. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Horizontal-Longitudinal Correlations of Acoustic Field in Deep Water

International Nuclear Information System (INIS)

Li Jun; Li Zheng-Lin; Ren Yun; Li Wen; Zhang Ren-He

2015-01-01

The horizontal-longitudinal correlations of the acoustic field in deep water are investigated based on the experimental data obtained in the South China Sea. It is shown that the horizontal-longitudinal correlation coefficients in the convergence zone are high, and the correlation length is consistent with the convergence zone width, which depends on the receiver depth and range. The horizontal-longitudinal correlation coefficients in the convergence zone also have a division structure for the deeper receiver. The signals from the second part of the convergence zone are still correlated with the reference signal in the first part. The horizontal-longitudinal correlation coefficients in the shadow zone are lower than that in the convergence zone, and the correlation length in the shadow zone is also much shorter than that in the convergence zone. The numerical simulation results by using the normal modes theory are qualitatively consistent with the experimental results. (paper)

A New Kicker for the TLS Longitudinal Feedback System

CERN Document Server

Lau, Wai-Keung; Dehler, Micha; Hsu, Kuo-Tung; Hsu, San-Yuang; Jung Chou Ping; Wei Chen, Cheng; Yang Chen Huan; Yang Tze Te

2005-01-01

A new longitudinal kicker that is modified from the Swiss Light Source (SLS) design to fit into the TLS storage ring. It will be served as the actuator in the longitudinal multi-bunch feedback control loop. Beam coupling impedance has been calculated by Gdfidl with a PC cluster. Previous to the installation of this new kicker, bench measurement has been performed in the laboratory to characterize this new kicker. The experimental setups for bandwidth and coaxial wire measurement of longitudinal coupling impedance and their corresponding test results will be reported. As a cross check, bead-pull measurement has also been done to verify the beam coupling measurement by coaxial wire method at the kicker center frequency. Longitudinal field profile of the accelerating mode along the beam path has also been mapped. High order cavity modes of the kicker have also been observed and their effects on the beam are evaluated.

Longitudinal muscle of the esophagus: its role in esophageal health and disease.

Science.gov (United States)

Mittal, Ravinder K

2013-07-01

The muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. The function of the longitudinal muscle and its role in bolus propulsion are not clear. The goal of this review is to summarize what is known of the role of the longitudinal muscle in health, as well as in sensory and motor disorders of the esophagus. Simultaneous manometry and ultrasound imaging reveal that, during peristalsis, the two muscle layers of the esophagus contract in perfect synchrony. On the contrary, during transient lower esophageal sphincter (LES) relaxation, longitudinal muscle contracts independent of the circular muscle. Recent studies have provided novel insights into the role of the longitudinal muscle in LES relaxation and descending relaxation of the esophagus. In certain diseases (e.g. some motility disorders of the esophagus), there is discoordination between the two muscle layers, which likely plays an important role in the genesis of dysphagia and delayed esophageal emptying. There is close temporal correlation between prolonged contractions of the longitudinal muscles of the esophagus and esophageal 'angina-like' pain. Novel techniques to record longitudinal muscle contraction are reviewed. Longitudinal muscles of the esophagus play a key role in the physiology and pathophysiology of esophageal sensory and motor function. Neuro-pharmacologic controls of circular and longitudinal muscle are different, which provides an opportunity for the development of novel pharmacological therapies in the treatment of esophageal sensory and motor disorders.

The re-identification risk of Canadians from longitudinal demographics

Science.gov (United States)

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

TMV nanorods with programmed longitudinal domains of differently addressable coat proteins

Science.gov (United States)

Geiger, Fania C.; Eber, Fabian J.; Eiben, Sabine; Mueller, Anna; Jeske, Holger; Spatz, Joachim P.; Wege, Christina

2013-04-01

The spacing of functional nanoscopic elements may play a fundamental role in nanotechnological and biomedical applications, but is so far rarely achieved on this scale. In this study we show that tobacco mosaic virus (TMV) and the RNA-guided self-assembly process of its coat protein (CP) can be used to establish new nanorod scaffolds that can be loaded not only with homogeneously distributed functionalities, but with distinct molecule species grouped and ordered along the longitudinal axis. The arrangement of the resulting domains and final carrier rod length both were governed by RNA-templated two-step in vitro assembly. Two selectively addressable TMV CP mutants carrying either thiol (TMVCys) or amino (TMVLys) groups on the exposed surface were engineered and shown to retain reactivity towards maleimides or NHS esters, respectively, after acetic acid-based purification and re-assembly to novel carrier rod types. Stepwise combination of CPCys and CPLys with RNA allowed fabrication of TMV-like nanorods with a controlled total length of 300 or 330 nm, respectively, consisting of adjacent longitudinal 100-to-200 nm domains of differently addressable CP species. This technology paves the way towards rod-shaped scaffolds with pre-defined, selectively reactive barcode patterns on the nanometer scale.The spacing of functional nanoscopic elements may play a fundamental role in nanotechnological and biomedical applications, but is so far rarely achieved on this scale. In this study we show that tobacco mosaic virus (TMV) and the RNA-guided self-assembly process of its coat protein (CP) can be used to establish new nanorod scaffolds that can be loaded not only with homogeneously distributed functionalities, but with distinct molecule species grouped and ordered along the longitudinal axis. The arrangement of the resulting domains and final carrier rod length both were governed by RNA-templated two-step in vitro assembly. Two selectively addressable TMV CP mutants carrying

Development of longitudinally excited CO2 laser

Science.gov (United States)

Masroon, N. S.; Tanaka, M.; Tei, M.; Uno, K.; Tsuyama, M.; Nakano, H.

2018-05-01

Simple, compact, and affordable discharged-pumped CO2 laser controlled by a fast high voltage solid state switch has been developed. In this study, longitudinal excitation scheme has been adapted for simple configuration. In the longitudinal excitation scheme, the discharge is produced along the direction of the laser axis, and the electrodes are well separated with a small discharge cross-section. Triggered spark gap switch is usually used to switch out the high voltage because of simple and low cost. However, the triggered spark gap operates in the arc mode and suffer from recovery problem causing a short life time and low efficiency for high repetition rate operation. As a result, there is now considerable interest in replacing triggered spark gap switch with solid state switches. Solid state switches have significant advantages compared to triggered spark gap switch which include longer service lifetime, low cost and stable high trigger pulse. We have developed simple and low cost fast high voltage solid state switch that consists of series connected-MOSFETs. It has been installed to the longitudinally excited CO2 laser to realize the gap switch less operation. Characteristics of laser oscillation by varying the discharge length, charging voltage, capacitance and gas pressure have been evaluated. Longer discharge length produce high power of laser oscillation. Optimum charging voltage and gas pressure were existed for longitudinally excited CO2 laser.

A Longitudinal Study of Adolescent Adjustment Following Family Transitions

Science.gov (United States)

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…

Longitudinal coupled-bunch instability studies in the PS

CERN Document Server

Damerau, H

2017-01-01

The main longitudinal limitation for LHC-type beams inthe PS are coupled-bunch instabilities. A dedicated proto-typefeedbacksystemusingaFinemetcavityasalongitudinalkicker has been installed. Extensive tests with beam havebeen performed to explore the intensity reach with this feed-back. The maximum intensity with nominal longitudinalemittance at PS extraction has been measured, as well as theemittance required to keep the beam longitudinally stableat the design intensity for the High-Luminosity LHC (HL-LHC). A higher-harmonic cavity is a complementary op-tion to extend the intensity reach beyond the capabilities ofthe coupled-bunch feedback. Preliminary machine develop-ment (MD) studies operating one20MHzor one40MHzRF system as a higher harmonic at the flat-top indicate thebeneficial effect on longitudinal beam stability

Using administrative data for longitudinal substance abuse research.

Science.gov (United States)

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

2010-04-01

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.

Simulation of the ALS longitudinal multibunch feedback system

International Nuclear Information System (INIS)

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

Comparing Longitudinal Profile Patterns of Mathematics and Reading in Early Child Longitudinal Study, Kindergarten: The Profile Analysis via Multidimensional Scaling (PAMS) Approach

Science.gov (United States)

Kim, Se-Kang

2010-01-01

The aim of the study is to compare longitudinal patterns from Mathematics and Reading data from the direct child assessment of Early Child Longitudinal Study, Kindergarten (ECLS-K, US Department of Education, National Center for Education Statistics 2006), utilizing Profile Analysis via Multidimensional Scaling (PAMS). PAMS has been used initially…

The value of right ventricular longitudinal strain in the evaluation of adult patients with repaired tetralogy of Fallot: a new tool for a contemporary challenge.

Science.gov (United States)

Almeida-Morais, Luís; Pereira-da-Silva, Tiago; Branco, Luísa; Timóteo, Ana T; Agapito, Ana; de Sousa, Lídia; Oliveira, José A; Thomas, Boban; Jalles-Tavares, Nuno; Soares, Rui; Galrinho, Ana; Cruz-Ferreira, Rui

2017-04-01

The role of right ventricular longitudinal strain for assessing patients with repaired tetralogy of Fallot is not fully understood. In this study, we aimed to evaluate its relation with other structural and functional parameters in these patients. Patients followed-up in a grown-up CHD unit, assessed by transthoracic echocardiography, cardiac MRI, and treadmill exercise testing, were retrospectively evaluated. Right ventricular size and function and pulmonary regurgitation severity were assessed by echocardiography and MRI. Right ventricular longitudinal strain was evaluated in the four-chamber view using the standard semiautomatic method. In total, 42 patients were included (61% male, 32±8 years). The mean right ventricular longitudinal strain was -16.2±3.7%, and the right ventricular ejection fraction, measured by MRI, was 42.9±7.2%. Longitudinal strain showed linear correlation with tricuspid annular systolic excursion (r=-0.40) and right ventricular ejection fraction (r=-0.45) (all ptetralogy of Fallot. It correlated with echocardiographic right ventricular function parameters and was independently associated with right ventricular ejection fraction derived by MRI.

Analyzing longitudinal data with the linear mixed models procedure in SPSS.

Science.gov (United States)

West, Brady T

2009-09-01

Many applied researchers analyzing longitudinal data share a common misconception: that specialized statistical software is necessary to fit hierarchical linear models (also known as linear mixed models [LMMs], or multilevel models) to longitudinal data sets. Although several specialized statistical software programs of high quality are available that allow researchers to fit these models to longitudinal data sets (e.g., HLM), rapid advances in general purpose statistical software packages have recently enabled analysts to fit these same models when using preferred packages that also enable other more common analyses. One of these general purpose statistical packages is SPSS, which includes a very flexible and powerful procedure for fitting LMMs to longitudinal data sets with continuous outcomes. This article aims to present readers with a practical discussion of how to analyze longitudinal data using the LMMs procedure in the SPSS statistical software package.

Increasing self-esteem and empathy to prevent violent radicalization: a longitudinal quantitative evaluation of a resilience training focused on adolescents with a dual identity

NARCIS (Netherlands)

Feddes, A.R.; Mann, L.; Doosje, B.

2015-01-01

Quantitative results are reported of a longitudinal evaluation of a resilience training as a possible method to prevent violent radicalization (Diamant; SIPI, 2010). A total of 46 male and female Muslim adolescents and young adults with a migrant background participated. Results show that the

Has the inclusion of a longitudinally integrated communication skills program improved consultation skills in medical students? A pilot study.

Science.gov (United States)

Shah, Sameena; Andrades, Marie; Basir, Fasia; Jaleel, Anila; Azam, Iqbal; Islam, Muhammad; Ahmed, Rashida

2016-01-01

Evidence highlights a lack of communication skills in doctors leading to dysfunctional consultations. To address this deficit, a private medical college instituted curricular reforms with inclusion of a longitudinal communication skills program. A pilot study was undertaken to evaluate the effectiveness of this program by comparing the consultation skills of medical students of this college with a medical college without a communication skills program. A 4-station Objective Structured Clinical Examination (OSCE) was conducted in the third and final year. Mann-Whitney U-test was used to compare the difference in the distribution between OSCE stations total and construct scores. At the end of the third year, 21 (31.34%), students of the study site (medical college 1 [college with integrated longitudinal communication skills program]) and 31 (46.26%) students from the comparison site (medical college 2 [comparable college without communication skills program]) consented. Medical college 1 achieved a significantly higher overall mean total station score of 68.0% (standard deviation [SD] =13.5) versus 57.2% (SD = 15.4) (P skills in an undergraduate curriculum positively impacted consultation skills. Community-based training and faculty development are required to develop effective patient-centered consultation skills.

Predictors for physical activity in adolescent girls using statistical shrinkage techniques for hierarchical longitudinal mixed effects models.

Directory of Open Access Journals (Sweden)

Edward M Grant

Full Text Available We examined associations among longitudinal, multilevel variables and girls' physical activity to determine the important predictors for physical activity change at different adolescent ages. The Trial of Activity for Adolescent Girls 2 study (Maryland contributed participants from 8th (2009 to 11th grade (2011 (n=561. Questionnaires were used to obtain demographic, and psychosocial information (individual- and social-level variables; height, weight, and triceps skinfold to assess body composition; interviews and surveys for school-level data; and self-report for neighborhood-level variables. Moderate to vigorous physical activity minutes were assessed from accelerometers. A doubly regularized linear mixed effects model was used for the longitudinal multilevel data to identify the most important covariates for physical activity. Three fixed effects at the individual level and one random effect at the school level were chosen from an initial total of 66 variables, consisting of 47 fixed effects and 19 random effects variables, in additional to the time effect. Self-management strategies, perceived barriers, and social support from friends were the three selected fixed effects, and whether intramural or interscholastic programs were offered in middle school was the selected random effect. Psychosocial factors and friend support, plus a school's physical activity environment, affect adolescent girl's moderate to vigorous physical activity longitudinally.

Operation of PEP longitudinal feedback system

International Nuclear Information System (INIS)

Allen, M.A.; Karvonen, L.G.; McConnell, R.A.; Schwarz, H.

1981-03-01

In order to suppress longitudinal coupled-bunch oscillations which might limit the capabilities of PEP, the 18 GeV e + e - storage ring at SLAC, a longitudinal feedback system is utilized. A frequency domain feedback system was chosen with the frequency spectrum of the stored beam being sampled close to a symmetry point in the ring where the feedback cavity itself is also located. The symmetry point chosen is symmetry point 5 which lies half-way between interaction regions 4 and 6. The system has been installed in PEP and is now operational. However, at stored currents up to the maximum stored in PEP to date at 14.5 GeV (approximately 40 mA in 6 bunches), the ring has been stable to all modes of longitudinal coupled-bunch oscillations both barycentric and the other fundamental modes. By deliberately detuning the main accelerating cavities, small multibunch oscillations can be introduced which, in turn, can be damped by the feedback system. Under optimized beam conditions the feedback system could be adjusted to positive feedback and excite oscillations with relatively small power to the feedback cavity. This will be described along with other details of the system

Longitudinal zonation of macroinvertebrates in an Ecuadorian glacier-fed stream: do tropical glacial systems fit the temperate model?

DEFF Research Database (Denmark)

Jacobsen, D.; Dangles, O.; Andino, P.

2010-01-01

P>1. The ecology of glacier-fed streams at temperate latitudes has been intensely studied in recent years, leading to the development of a well-validated conceptual model on the longitudinal distribution of macroinvertebrate communities downstream of the glacier margin (Freshwater Biology, 2001a...... of the equator in the Ecuadorian Andes. Our goal was to study the longitudinal distribution of the fauna in relation to environmental factors and to compare this with the conceptual model based on temperate-arctic glacier-fed streams. 3. Total density of invertebrates differed considerably at the two highest...... was numerous at the highest sites but became much less important further downstream. The Orthocladiinae were important both in numbers and species at all sites, while Diamesinae were numerous only in the middle of the reach studied and were completely absent from the upper three sites. The limited importance...

A Longitudinal Study of Neurocognition in Dementia with Lewy Bodies Compared to Alzheimer’s Disease

Directory of Open Access Journals (Sweden)

Monica H. Breitve

2018-03-01

Full Text Available IntroductionThere are relatively few longitudinal studies on the differences in cognitive decline between Alzheimer’s disease (AD and dementia with Lewy bodies (DLB, and the majority of existing studies have suboptimal designs.AimWe investigated the differences in cognitive decline in AD compared to DLB over 4 years and cognitive domain predictors of progression.MethodsIn a longitudinal study, 266 patients with first-time diagnosis of mild dementia were included and followed annually. The patients were tested annually with neuropsychological tests and screening instruments [MMSE (Mini-Mental Status Examination, Clinical Dementia Rating (CDR, the second edition of California Verbal Learning Test (CVLT-II, Trail Making Test A & B (TMT A & B, Stroop test, Controlled Oral Word Associations Test (COWAT animal naming, Boston Naming Test, Visual Object and Space Perception Battery (VOSP Cubes and Silhouettes]. Longitudinal analyses were performed with linear mixed effects (LME models and Cox regression. Both specific neuropsychological tests and cognitive domains were analyzed.ResultsThis study sample comprised 119 AD and 67 DLB patients. In TMT A, the DLB patients had a faster decline over 4 years than patients with AD (p = 0.013. No other longitudinal differences in specific neuropsychological tests were found. Higher executive domain scores at baseline were associated with a longer time to reach severe dementia (CDR = 3 or death for the total sample (p = 0.032. High or low visuospatial function at baseline was not found to be associated with cognitive decline (MMSE or progression of dementia severity (CDR over time.ConclusionOver 4 years, patients with DLB had a faster decline in TMT A than patients with AD, but this should be interpreted cautiously. Beyond this, there was little support for faster decline in DLB patients neuropsychologically than in AD patients.

Longitudinal anthropometric assessment of infants born to HIV-1-infected mothers, Belo Horizonte, Southeastern Brazil

OpenAIRE

Fausto, Maria Arlene; Carneiro, Mariângela; Antunes, Carlos Maurício F; Colosimo, Enrico Antonio; Pinto, Jorge Andrade

2011-01-01

OBJECTIVE: To evaluate the growth parameters in infants who were born to HIV-1-infected mothers. METHODS: The study was a longitudinal evaluation of the z-scores for the weight-for-age (WAZ), weight-for-length (WLZ) and length-for-age (LAZ) data collected from a cohort. A total of 97 non-infected and 33 HIV-infected infants born to HIV-1-infected mothers in Belo Horizonte, Southeastern Brazil, between 1995 and 2003 was studied. The average follow-up period for the infected and non-infected ch...

Exposure to violent video games and aggression in German adolescents: a longitudinal analysis.

Science.gov (United States)

Möller, Ingrid; Krahé, Barbara

2009-01-01

The relationship between exposure to violent electronic games and aggressive cognitions and behavior was examined in a longitudinal study. A total of 295 German adolescents completed the measures of violent video game usage, endorsement of aggressive norms, hostile attribution bias, and physical as well as indirect/relational aggression cross-sectionally, and a subsample of N=143 was measured again 30 months later. Cross-sectional results at T1 showed a direct relationship between violent game usage and aggressive norms, and an indirect link to hostile attribution bias through aggressive norms. In combination, exposure to game violence, normative beliefs, and hostile attribution bias predicted physical and indirect/relational aggression. Longitudinal analyses using path analysis showed that violence exposure at T1 predicted physical (but not indirect/relational) aggression 30 months later, whereas aggression at T1 was unrelated to later video game use. Exposure to violent games at T1 influenced physical (but not indirect/relational) aggression at T2 via an increase of aggressive norms and hostile attribution bias. The findings are discussed in relation to social-cognitive explanations of long-term effects of media violence on aggression. Copyright 2008 Wiley-Liss, Inc.

Plantar fascia thickness is longitudinally associated with retinopathy and renal dysfunction: a prospective study from adolescence to adulthood.

Science.gov (United States)

Benitez-Aguirre, Paul Z; Craig, Maria E; Jenkins, Alicia J; Gallego, Patricia H; Cusumano, Janine; Duffin, Anthony C; Hing, Stephen; Donaghue, Kim C

2012-03-01

The aim was to study the longitudinal relationship between plantar fascia thickness (PFT) as a measure of tissue glycation and microvascular (MV) complications in young persons with type 1 diabetes (T1DM). We conducted a prospective longitudinal cohort study of 152 (69 male) adolescents with T1DM who underwent repeated MV complications assessments and ultrasound measurements of PFT from baseline (1997-2002) until 2008. Retinopathy was assessed by 7-field stereoscopic fundal photography and nephropathy by albumin excretion rate (AER) from three timed overnight urine specimens. Longitudinal analysis was performed using generalized estimating equations (GEE). Median (interquartile range) age at baseline was 15.1 (13.4-16.8) years, and median follow-up was 8.3 (7.0-9.5) years, with 4 (3-6) visits per patient. Glycemic control improved from baseline to final visit [glycated hemoglobin (HbA1c) 8.5% to 8.0%, respectively; p = .004]. Prevalence of retinopathy increased from 20% to 51% (p 7.5 μg/min) increased from 26% to 29% (p = .2). A greater increase in PFT (mm/year) was associated with retinopathy at the final assessment (ΔPFT 1st vs. 2nd-4th quartiles, χ(2) = 9.87, p = .02). In multivariate GEE, greater PFT was longitudinally associated with retinopathy [odds ratio (OR) 4.6, 95% confidence interval (CI) 2.0-10.3] and early renal dysfunction (OR 3.2, CI 1.3-8.0) after adjusting for gender, blood pressure standard deviation scores, HbA1c, and total cholesterol. In young people with T1DM, PFT was longitudinally associated with retinopathy and early renal dysfunction, highlighting the importance of early glycemic control and supporting the role of metabolic memory in MV complications. Measurement of PFT by ultrasound offers a noninvasive estimate of glycemic burden and tissue glycation. © 2012 Diabetes Technology Society.

Proximal alveolar bone loss in a longitudinal radiographic investigation

International Nuclear Information System (INIS)

Lavstvedt, S.; Bolin, A.; Henrikson, C.O.; Carstensen, J.

1986-01-01

A longitudinal radiographic investigation was made of the progression of the proximal alveolar bone loss over a 10-year period (1970-1980). The material was unselected and consisted of 669 individuals in the county of Stockholm. 61 individuals were randomly selected for evaluation of a recording system using alternative methods of measurement, and 90% of the measurement sites could then be assessed. The correlations between some of the methods were high, such as between measurement of alveolar bone height and root length and between aleveolar bone height and tooth length. To reduce the number of measurements, a partial recording was made, giving a high correlation coefficient between the partial recording and total recording. When five measurement sites were used, the correlation coefficient was 0.96, and a slight increase of the coefficient was obtained when using additional sites

Longitudinal dynamics and stability in beams for heavy-ion fusion

International Nuclear Information System (INIS)

Sharp, W.M.; Callahan, D.A.; Grote, D.P.

1996-01-01

Successful transport of induction-driven beams for heavy-ion fusion requires careful control of the longitudinal space charge. The usual control technique is the periodic application of time-varying longitudinal electric fields, called 'ears', that on the average, balance the space-charge field. this technique is illustrated using a fluid/envelope code CIRCE, and the sensitivity of the method to errors in these ear fields is illustrated. The possibility that periodic ear fields also excite the longitudinal instability is examined

Measurements of longitudinal phase space in the SLC linac

International Nuclear Information System (INIS)

Bane, K.; Adolphsen, C.; Lavine, T.L.; Ross, M.; Seeman, J.; Thompson, K.

1990-05-01

In the Stanford Linear Collider the beam leaves a damping ring and then enters the Ring-to-Linac (RTL) transfer line. In the RTL it is compressed in length by a factor of 10 by means of an rf section, with which a longitudinally correlated energy variation is induced in the beam, and a following beam line which has non-zero momentum compaction. The compressed beam then enters the linac proper. In this paper we describe three measurements of longitudinal properties of the beam in the SLC linac. We present measurements of single bunch beam loading, of the energy spectrum at the end of the linac, and of the linac bunch length. Since the results of all three measurements depend on the beam's longitudinal charge distribution in the linac they, in turn, also depend on the bunch lengthening that occurs in the damping rings, as well as on the behavior of the compressor. The results of the first two measurements, in addition, depend critically on the strength of the longitudinal wakefields in the linac. The results of these three measurements are compared with simulations. For these calculations, at any given current, the potential well distortion in the damping ring is first computed. The compression process is then simulated to obtain the longitudinal charge distribution in the linac. For the first two measurements this distribution is then convolved with the calculated longitudinal wake function of the SLAC linac in order to obtain the induced voltage. Finally, the induced voltage is combined with the effect of the linac rf wave to give the final energy spectrum. 8 refs., 5 figs

ABRUPT LONGITUDINAL MAGNETIC FIELD CHANGES IN FLARING ACTIVE REGIONS

International Nuclear Information System (INIS)

Petrie, G. J. D.; Sudol, J. J.

2010-01-01

We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within 65 0 of disk center using 1 minute GONG magnetograms. In all 77 cases, we identify at least one site in the flaring active region where clear, permanent, stepwise field changes occurred. The median duration of the field changes was about 15 minutes and was approximately equal for X-class and for M-class flares. The absolute values of the field changes ranged from the detection limit of ∼10 G to as high as ∼450 G in two exceptional cases. The median value was 69 G. Field changes were significantly stronger for X-class than for M-class flares and for limb flares than for disk-center flares. Longitudinal field changes less than 100 G tended to decrease longitudinal field strengths, both close to disk center and close to the limb, while field changes greater than 100 G showed no such pattern. Likewise, longitudinal flux strengths tended to decrease during flares. Flux changes, particularly net flux changes near disk center, correlated better than local field changes with GOES peak X-ray flux. The strongest longitudinal field and flux changes occurred in flares observed close to the limb. We estimate the change of Lorentz force associated with each flare and find that this is large enough in some cases to power seismic waves. We find that longitudinal field decreases would likely outnumber increases at all parts of the solar disk within 65 0 of disk center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.

Residents’ perceptions of an integrated longitudinal curriculum: a qualitative study

Directory of Open Access Journals (Sweden)

Rebecca Lubitz

2015-12-01

Conclusions: This study suggests that an integrated longitudinalized family medicine block training model has the potential to support the principles of a longitudinal integrated competency-based curriculum to effectively prepare residents for family medicine practice.

Social support, social strain and inflammation: Evidence from a national longitudinal study of U.S. adults

Science.gov (United States)

Yang, Yang Claire; Schorpp, Kristen; Harris, Kathleen Mullan

2014-01-01

Social relationships have long been held to have powerful effects on health and survival, but it remains unclear whether such associations differ by function and domain of relationships over time and what biophysiological mechanisms underlie these links. This study addressed these gaps by examining the longitudinal associations of persistent relationship quality across a ten year span with a major indicator of immune function. Specifically, we examined how perceived social support and social strain from relationships with family, friends, and spouse at a prior point in time are associated with subsequent risks of inflammation, as assessed by overall inflammation burden comprised of five markers (C-reactive protein, interleukin-6, fibrinogen, E-selectin, and intracellular adhesion molecule-1) in a national longitudinal study of 647 adults from the Midlife Development in the United States (1995–2009). Results from multivariate regression analysis show that (1) support from family, friends, and spouse modestly protected against risks of inflammation; (2) family, friend, and total social strain substantially increased risks of inflammation; and (3) the negative associations of social strain were stronger than the positive associations of social support with inflammation. The findings highlight the importance of enriched conceptualizations, measures, and longitudinal analyses of both social and biological stress processes to elucidate the complex pathways linking social relationships to health and illness. PMID:24607674

Antisocial Behavior and Depressive Symptoms: Longitudinal and Concurrent Relations

Science.gov (United States)

Vieno, Alessio; Kiesner, Jeff; Pastore, Massimiliano; Santinello, Massimo

2008-01-01

The relations between antisocial behavior and depressive symptoms were examined both longitudinally and concurrently in a sample of Italian early-adolescents. Structural equation modelling was applied to 10-month longitudinal data from a sample of 107 youths (54 girls; mean age at baseline = M = 12.5). Early adolescents completed a questionnaire…

Longitudinal optical monitoring of blood flow in breast tumors during neoadjuvant chemotherapy

Science.gov (United States)

Cochran, J. M.; Chung, S. H.; Leproux, A.; Baker, W. B.; Busch, D. R.; DeMichele, A. M.; Tchou, J.; Tromberg, B. J.; Yodh, A. G.

2017-06-01

We measure tissue blood flow markers in breast tumors during neoadjuvant chemotherapy and investigate their correlation to pathologic complete response in a pilot longitudinal patient study (n  =  4). Tumor blood flow is quantified optically by diffuse correlation spectroscopy (DCS), and tissue optical properties, blood oxygen saturation, and total hemoglobin concentration are derived from concurrent diffuse optical spectroscopic imaging (DOSI). The study represents the first longitudinal DCS measurement of neoadjuvant chemotherapy in humans over the entire course of treatment; it therefore offers a first correlation between DCS flow indices and pathologic complete response. The use of absolute optical properties measured by DOSI facilitates significant improvement of DCS blood flow calculation, which typically assumes optical properties based on literature values. Additionally, the combination of the DCS blood flow index and the tissue oxygen saturation from DOSI permits investigation of tissue oxygen metabolism. Pilot results from four patients suggest that lower blood flow in the lesion-bearing breast is correlated with pathologic complete response. Both absolute lesion blood flow and lesion flow relative to the contralateral breast exhibit potential for characterization of pathological response. This initial demonstration of the combined optical approach for chemotherapy monitoring provides incentive for more comprehensive studies in the future and can help power those investigations.

Longitudinal myelitis associated with yellow fever vaccination.

Science.gov (United States)

Chaves, M; Riccio, P; Patrucco, L; Rojas, J I; Cristiano, E

2009-07-01

Severe adverse reaction to yellow fever (YF) vaccine includes the yellow fever vaccine-associated neurotropic disease. This terminology includes postvaccinal encephalitis, acute disseminated encephalomyelitis, and Guillain-Barré syndrome. The objective of this communication is to report a patient who received a YF vaccine in Argentina and subsequently developed longitudinal myelitis with a symptom that had previously gone unreported in the literature. A 56-year-old man began with progressive paraparesia, urinary retention, and constipation 48 h previous to admission. The patient received YF vaccine 45 days prior to the onset of the symptoms. There was no history of other immunization or relevant condition. MR of the spine showed longitudinal intramedullary hyperintense signal (D5-12) without gadolinium enhancement. A high concentration of YFV-specific IgM vaccine antibody was found in the cerebrospinal fluid (CSF). Serological tests for other flavivirus were negative. A diagnosis of longitudinal myelitis without encephalitis associated with YF vaccine was performed and symptoms improved 5 days later. This is the first report dealing with longitudinal myelitis as a serious adverse event associated with YF vaccination in which confirmation of the presence of antibodies in CSF was found. To date, it is also the first report with serological confirmation in Argentina and in South America. We consider that the present investigation will raise awareness in the region in the reporting of adverse events related to YF vaccine and improve our knowledge of adverse reactions to the vaccine.

Longitudinal and transverse polarizations in the deep inelastic reactions

International Nuclear Information System (INIS)

Bressan, A.

1996-07-01

This course is an introduction to the dominant effects of longitudinal and transverse spin in deep inelastic reactions. Only the effects present to the 'leading twist' are attacked. The mass and transverse impulsion of partons are neglected. We will attach to bring out the respective specificities of longitudinal and transverse polarizations. (N.C.)

Single bunch fast longitudinal instability

International Nuclear Information System (INIS)

Wang, J.M.; Pellegrini, C.

1979-01-01

Single bunch longitudinal instability producing an increase of the bunch areas has been observed in proton synchrotron and storage rings. Singals at microwave frequencies are observed during the bunch blow-up and because of this the effect has been called the microwave instability. A similar increase in bunch area is observed also in electron storage rings, where it is usually referred to as the bunch lengthening effect. This paper is an attempt to obtain a more general theory of this effect. Here we describe the model used and the method of calculation, together with some general results. The main result of this paper is the derivation of a condition for the existence of a fast longitudinal bunch blow-up. This condition is a generalized threshold formula, showing explicitly the dependence on the bunch energy spread and length

Simulations of longitudinally pumped dye laser amplifier

International Nuclear Information System (INIS)

Takehisa, Kiwamu; Takemori, Satoshi

1995-01-01

Simulations of a copper laser pumped dye laser amplifier and new designs of the longitudinally pumped dye laser amplifier are presented. The simulations take the consideration of the amplified spontaneous emission (ASE). The new designs utilize a center-hole reflector instead of a dichroic mirror. The simulation results indicate that the poor spatial overlap between the pump beam and the dye beam in the transverse pumping not only reduces the laser output power, but also generates ASE strongly. The results also indicate that the longitudinal pumping is as efficient as the transverse pumping. (author)

Longitudinal tibial epiphyseal bracket in Nievergelt syndrome

International Nuclear Information System (INIS)

Burnstein, M.I.; De Smet, A.A.; Breed, A.L.; Thomas, J.R.; Hafez, G.R.

1989-01-01

A patient is described with lower extremity mesomelic dwarfism associated with bilateral congenital elbow, hip, and knee dislocations. Rhomboid-shaped tibiae and delayed ossification of the primary fibular ossification centers were demonstrated at birth. Plain films and magnetic resonance imaging revealed that the tibial deformities were due to the presence of longitudinal epiphyseal brackets. These brackets were observed at surgery and confirmed histologically. Recognition of the longitudinal epiphyseal bracket and its relationship to the tibial deformities seen in this patient with Nievergelt syndrome is important for planning surgical treatment. (orig.)

Longitudinal tibial epiphyseal bracket in Nievergelt syndrome

Energy Technology Data Exchange (ETDEWEB)

Burnstein, M.I.; De Smet, A.A.; Breed, A.L.; Thomas, J.R.; Hafez, G.R.

1989-04-01

A patient is described with lower extremity mesomelic dwarfism associated with bilateral congenital elbow, hip, and knee dislocations. Rhomboid-shaped tibiae and delayed ossification of the primary fibular ossification centers were demonstrated at birth. Plain films and magnetic resonance imaging revealed that the tibial deformities were due to the presence of longitudinal epiphyseal brackets. These brackets were observed at surgery and confirmed histologically. Recognition of the longitudinal epiphyseal bracket and its relationship to the tibial deformities seen in this patient with Nievergelt syndrome is important for planning surgical treatment. (orig.).

A ¤nonparametric dynamic additive regression model for longitudinal data

DEFF Research Database (Denmark)

Martinussen, T.; Scheike, T. H.

2000-01-01

dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models......dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models...

Formation of longitudinal axon pathways in Caenorhabditis elegans.

Science.gov (United States)

Hutter, Harald

2017-11-18

The small number of neurons and the simple architecture of the Caenorhabditis elegans (C. elegans) nervous system enables researchers to study axonal pathfinding at the level of individually identified axons. Axons in C. elegans extend predominantly along one of the two major body axes, the anterior-posterior axis and the dorso-ventral axis. This review will focus on axon navigation along the anterior-posterior axis, leading to the establishment of the longitudinal axon tracts, with a focus on the largest longitudinal axon tract, the ventral nerve cord (VNC). In the VNC, axons grow out in a stereotypic order, with early outgrowing axons (pioneers) playing an important role in guiding later outgrowing (follower) axons. Genetic screens have identified a number of genes specifically affecting the formation of longitudinal axon tracts. These genes include secreted proteins, putative receptors and adhesion molecules, as well as intracellular proteins regulating the cell's response to guidance cues. In contrast to dorso-ventral navigation, no major general guidance cues required for the establishment of longitudinal pathways have been identified so far. The limited penetrance of defects found in many mutants affecting longitudinal navigation suggests that guidance cues act redundantly in this process. The majority of the axon guidance genes identified in C. elegans are evolutionary conserved, i.e. have homologs in other animals, including vertebrates. For a number of these genes, a role in axon guidance has not been described outside C. elegans. Taken together, studies in C. elegans contribute to a fundamental understanding of the molecular basis of axonal navigation that can be extended to other animals, including vertebrates and probably humans as well. Copyright © 2017. Published by Elsevier Ltd.

Suppression of Longitudinal Coupled-Bunch Instabilities at the KEK-PF

International Nuclear Information System (INIS)

Obina, T.; Tobiyama, M.; Honda, T.; Tadano, M.; Flanagan, J.W.; Mitsuhashi, T.; Cheng, W.X.; Fox, J.D.; Teytelman, D.

2012-01-01

A bunch-by-bunch feedback system has been developed to suppress longitudinal coupled-bunch instabilities at the KEK-PF. A longitudinal kicker based on a DAFNE-type overdamped cavity has been designed and installed in the ring, and a general purpose signal processor, called iGp, has been developed by the collaboration of the KEK, SLAC, and INFN-LNF. The entire feedback loop has been closed by the end of June 2007, and the feedback system has successfully suppressed the longitudinal dipole-mode instabilities up to 430 mA.

Longitudinal halo in beam bunches with self-consistent 6-D distributions

International Nuclear Information System (INIS)

Gluckstern, R. L.; Fedotov, A. V.; Kurennoy, S. S.; Ryne, R. D.

1998-01-01

We have explored the formation of longitudinal and transverse halos in 3-D axisymmetric beam bunches by starting with a self-consistent 6-D phase space distribution. Stationary distributions allow us to study the halo development mechanism without being obscured by beam redistribution and its effect on halo formation. The beam is then mismatched longitudinally and/or transversely, and we explore the rate, intensity and spatial extent of the halos which form, as a function of the beam charge and the mismatches. We find that the longitudinal halo forms first because the longitudinal tune depression is more severe than the transverse one for elongated bunches and conclude that it plays a major role in halo formation

Time-dependent efficacy of longitudinal biomarker for clinical endpoint.

Science.gov (United States)

Kolamunnage-Dona, Ruwanthi; Williamson, Paula R

2018-06-01

Joint modelling of longitudinal biomarker and event-time processes has gained its popularity in recent years as they yield more accurate and precise estimates. Considering this modelling framework, a new methodology for evaluating the time-dependent efficacy of a longitudinal biomarker for clinical endpoint is proposed in this article. In particular, the proposed model assesses how well longitudinally repeated measurements of a biomarker over various time periods (0,t) distinguish between individuals who developed the disease by time t and individuals who remain disease-free beyond time t. The receiver operating characteristic curve is used to provide the corresponding efficacy summaries at various t based on the association between longitudinal biomarker trajectory and risk of clinical endpoint prior to each time point. The model also allows detecting the time period over which a biomarker should be monitored for its best discriminatory value. The proposed approach is evaluated through simulation and illustrated on the motivating dataset from a prospective observational study of biomarkers to diagnose the onset of sepsis.

Longitudinal associations between different dementia diagnoses and medication use jointly accounting for dropout.

Science.gov (United States)

Agogo, George O; Ramsey, Christine M; Gnjidic, Danijela; Moga, Daniela C; Allore, Heather

2018-04-18

ABSTRACTBackground:Longitudinal studies of older adults are characterized by high dropout rates, multimorbid conditions, and multiple medication use, especially proximal to death. We studied the association between multiple medication use and incident dementia diagnoses including Alzheimer's disease (AD), vascular dementia (VD), and Lewy-body dementia (LBD), simultaneously accounting for dropout. Using the National Alzheimer's Coordinating Center data with three years of follow-up, a set of covariate-adjusted models that ignore dropout was fit to complete-case data, and to the whole-cohort data. Additionally, covariate-adjusted joint models with shared random effects accounting for dropout were fit to the whole-cohort data. Multiple medication use was defined as polypharmacy (⩾ five medications), hyperpolypharmacy (⩾ ten medications), and total number of medications. Incident diagnoses were 2,032 for AD, 135 for VD, and 139 for LBD. Percentages of dropout at the end of follow-up were as follows: 71.8% for AD, 81.5% for VD, and 77.7% for LBD. The odds ratio (OR) estimate for hyperpolypharmacy among those with LBD versus AD was 2.19 (0.78, 6.15) when estimated using complete-case data and 3.00 (1.66, 5.40) using whole-cohort data. The OR reduced to 1.41 (0.76, 2.64) when estimated from the joint model accounting for dropout. The OR for polypharmacy using complete-case data differed from the estimates using whole-cohort data. The OR for dementia diagnoses on total number of medications was similar, but non-significant when estimated using complete-case data. Reasons for dropout should be investigated and appropriate statistical methods should be applied to reduce bias in longitudinal studies among high-risk dementia cohorts.

Combined lateral and longitudinal CACC for a unicycle-type platoon

NARCIS (Netherlands)

Bayuwindra, A.; Aakre, O.L.; Ploeg, J.; Nijmeijer, H.

2016-01-01

This paper presents the controller design for combined lateral and longitudinal Cooperative Adaptive Cruise Control (CACC) for a unicycle-type platoon with emphasis on the cornering maneuvers. A decentralized controller for lateral and longitudinal behavior is designed using input-output

Fingerprints of transversal and longitudinal coupling between induced open quantum dots in the longitudinal magneto-conductance through anti-dot lattices

International Nuclear Information System (INIS)

Ujevic, Sebastian; Mendoza, Michel

2011-01-01

Full text. We propose numerical simulations of longitudinal magneto conductance through a finite anti dot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magneto conductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magneto conductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the anti dot lattice. A relationship is observed between the distribution of anti dots and the formed conductance bands, allowing a systematic follow-up of the bands as a function of the applied magnetic field and quantum point contact width. We observed a high conductance intensity (between n- and (n + 1)-quantum of conductance, n = 1; 2...) in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the anti dots potential and the quantum point contact width. A new continuous channel (not expected) is induced by the variation of the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field

Nucleon Spin Structure: Longitudinal and Transverse

International Nuclear Information System (INIS)

Chen, Jian-Ping

2011-01-01

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.

HbA1c, diabetes and cognitive decline: the English Longitudinal Study of Ageing.

Science.gov (United States)

Zheng, Fanfan; Yan, Li; Yang, Zhenchun; Zhong, Baoliang; Xie, Wuxiang

2018-04-01

The aim of the study was to evaluate longitudinal associations between HbA 1c levels, diabetes status and subsequent cognitive decline over a 10 year follow-up period. Data from wave 2 (2004-2005) to wave 7 (2014-2015) of the English Longitudinal Study of Ageing (ELSA) were analysed. Cognitive function was assessed at baseline (wave 2) and reassessed every 2 years at waves 3-7. Linear mixed models were used to evaluate longitudinal associations. The study comprised 5189 participants (55.1% women, mean age 65.6 ± 9.4 years) with baseline HbA 1c levels ranging from 15.9 to 126.3 mmol/mol (3.6-13.7%). The mean follow-up duration was 8.1 ± 2.8 years and the mean number of cognitive assessments was 4.9 ± 1.5. A 1 mmol/mol increment in HbA 1c was significantly associated with an increased rate of decline in global cognitive z scores (-0.0009 SD/year, 95% CI -0.0014, -0.0003), memory z scores (-0.0005 SD/year, 95% CI -0.0009, -0.0001) and executive function z scores (-0.0008 SD/year, 95% CI -0.0013, -0.0004) after adjustment for baseline age, sex, total cholesterol, HDL-cholesterol, triacylglycerol, high-sensitivity C-reactive protein, BMI, education, marital status, depressive symptoms, current smoking, alcohol consumption, hypertension, CHD, stroke, chronic lung disease and cancer. Compared with participants with normoglycaemia, the multivariable-adjusted rate of global cognitive decline associated with prediabetes and diabetes was increased by -0.012 SD/year (95% CI -0.022, -0.002) and -0.031 SD/year (95% CI -0.046, -0.015), respectively (p for trend cognitive decline with diabetes. Significant longitudinal associations between HbA 1c levels, diabetes status and long-term cognitive decline were observed in this study. Future studies are required to determine the effects of maintaining optimal glucose control on the rate of cognitive decline in people with diabetes.

Associations Between Statin Use and Physical Function in Older Adults from The Netherlands and Australia: Longitudinal Aging Study Amsterdam and Australian Longitudinal Study on Women's Health.

Science.gov (United States)

van Boheemen, Laurette; Tett, Susan E; Sohl, Evelien; Hugtenburg, Jacqueline G; van Schoor, Natasja M; Peeters, G M E E

2016-06-01

Statin therapy may cause myopathy, but long-term effects on physical function are unclear. We investigated whether statin use is associated with poorer physical function in two population-based cohorts of older adults. Data were from 691 men and women (aged 69-102 years in 2005/2006) in the LASA (Longitudinal Aging Study Amsterdam) and 5912 women (aged 79-84 years in 2005) in the ALSWH (Australian Longitudinal Study on Women's Health). Statin use and dose were sourced from containers (LASA) and administrative databases (ALSWH). Physical function was assessed using performance tests, questionnaires on functional limitations and the SF-12 (LASA) and SF-36 (ALSWH) questionnaires. Cross-sectional (both studies) and 3-year prospective associations (ALSWH) were analysed for different statin dosage using linear and logistic regression. In total, 25 % of participants in LASA and 61 % in ALSWH used statins. In the cross-sectional models in LASA, statin users were less likely to have functional limitations (percentage of subjects with at least 1 limitation 63.9 vs. 64.2; odds ratio [OR] 0.6; 95 % confidence interval [CI] 0.3-0.9) and had better SF-12 physical component scores (mean [adjusted] 47.3 vs. 44.5; beta [B] = 2.8; 95 % CI 1.1-4.5); in ALSWH, statin users had better SF-36 physical component scores (mean [adjusted] 37.4 vs. 36.5; B = 0.9; 95 % CI 0.3-1.5) and physical functioning subscale scores (mean [adjusted] 55.1 vs. 52.6; B = 2.4; 95 % CI 1.1-3.8) than non-users. Similar associations were found for low- and high-dose users and in the prospective models. In contrast, no significant associations were found with performance tests. Two databases from longitudinal population studies in older adults gave comparable results, even though different outcome measures were used. In these two large cohorts, statin use was associated with better self-perceived physical function.

[Longitudinal and specific analyses of physical performance in handball].

Science.gov (United States)

Schwesig, R; Fieseler, G; Jungermann, P; Noack, F; Irlenbusch, L; Leuchte, S; Fischer, D

2012-09-01

Sports-specific, biomechanical measuring stations and measuring-station trainings have become common practice in many forms of sports and are an essential element of the complex assessment of physical performance. In handball, however, there is still considerable research potential in this respect as well as in the systematic generation and acquisition of the requirements profile and progress of strain. The prime objective of the longitudinal study was to determine the potential performance and development of handball players (3 rd league) in general and in terms of handball sport in particular. Another objective was to establish correlations between tests and indicators of performance in competitions. 13 handball players (age: 26.5 ± 3.6 years) were tested three times (before and after the pre-season preparation phase and at the end of the first half of the season) on two test days each. The examination was composed of sprint test (ST, day 1), handball-specific complex test (HBKT, day 1) and assessment of treadmill diagnostics (LD, day 2). The surveyed parameters were lactate and heart rate (LD/HBKT) as well as time (ST, HBKT) and the number of errors (HBKT). The cardiac (Hfmax = 201 min-1) and metabolic strain (lactate = 17.8 mmol/L) in the HBKT were very high. In the preparatory phase, the average magnitudes of effect registered were at d = 0.31 (ST parameter), d = 0.68 (HBKT parameter) and d = 0.98 (LD parameter). The most significant improvements throughout the entire period of time were registered in the parameters v2 (LD; η2 = 0.371), total goal-throwing time (HBKT; η2 = 0.250), total penalty time (HBKT; η2 = 0.236) and total round 2 (HBKT; η2 = 0.227). In HBKT and LD, the performance level was stabilised by the end of the first half of the season. In terms of speed, however, there was a decline in performance abilities. The competition performance has its highest degree of correlation with cardial (defense: r = -0.656) and metabolic (offensive: r = -0

Three-dimensional total variation norm for SPECT reconstruction

International Nuclear Information System (INIS)

Persson, Mikael; Bone, Dianna; Elmqvist, H.

2001-01-01

The total variation (TV) norm has been described in literature as a method for reducing noise in two-dimensional (2D) images. At the same time, the TV-norm is very good at recovering edges in images, without introducing ringing or edge artefacts. It has also been proposed as a 2D regularisation function in Bayesian reconstruction, implemented in an expectation maximisation (EM) algorithm, and called TV-EM. The TV-EM was developed for 2D SPECT imaging, and the algorithm is capable of smoothing noise while maintaining edges without introducing artefacts. We have extended the TV-norm to take into account the third spatial dimension, and developed an iterative EM algorithm based on the three-dimensional (3D) TV-norm, which we call TV3D-EM. This takes into account the correlation between transaxial sections in SPECT, due to system resolution. We have compared the 2D and 3D algorithms using reconstructed images from simulated projection data. Phantoms used were a homogeneous sphere, and a 3D head phantom based on the Shepp-Logan phantom. The TV3D-EM algorithm yielded somewhat lower noise levels than TV-EM. The noise in the TV3D-EM had similar correlation in transaxial and longitudinal sections, which was not the case for TV-EM, or any 2D reconstruction method. In particular, longitudinal sections from TV3D-EM were perceived as less noisy when compared to TV-EM. The use of 3D reconstruction should also be advantageous if compensation for distant dependent collimator blurring is incorporated in the iterative algorithm

Estado nutricional de pré-escolares de creche pública: um estudo longitudinal

OpenAIRE

Pereira,Alessandra da Silva; Peixoto,Natasha Gabrielle de Araújo; Nogueira Neto,José Firmino; Lanzillotti,Haydée Serrão; Soares,Eliane de Abreu

2013-01-01

O objetivo do estudo foi monitorar o estado nutricional de pré-escolares de uma creche pública. Trata-se de um estudo longitudinal, antes (t0) e depois (t1), com 51 crianças de 2 a 4 anos de idade. Os procedimentos foram: avaliação antropométrica (P/I, P/E e E/I - OMS 2006, classificação SISVAN-2008); avaliação bioquímica (colesterol total, HDLc, LDLc, triglicerídeos e glicose); avaliação hematológica (hemoglobina); avaliação dietética (pesagem direta dos alimentos e registro alimentar). Para...

Multivariate longitudinal data analysis with mixed effects hidden Markov models.

Science.gov (United States)

Raffa, Jesse D; Dubin, Joel A

2015-09-01

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

Correspondence analysis of longitudinal data

NARCIS (Netherlands)

Van der Heijden, P.G.M.|info:eu-repo/dai/nl/073087998

2005-01-01

Correspondence analysis is an exploratory tool for the analysis of associations between categorical variables, the results of which may be displayed graphically. For longitudinal data with two time points, an analysis of the transition matrix (showing the relative frequencies for pairs of

Longitudinal heritability of childhood aggression

NARCIS (Netherlands)

Porsch, R.M.P.; Middeldorp, C.M.; Cherny, S.S.; Krapohl, E.; van Beijsterveldt, C.E.M.; Loukola, A.; Korhonen, T.; Pulkkinen, L.; Corley, R.P.; Rhee, S.; Kaprio, J.; Rose, R.; Hewitt, J.K.; Sham, P.; Plomin, R.; Boomsma, D.I.; Bartels, M.

2016-01-01

The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression

Defining SNAP by cross-sectional and longitudinal definitions of neurodegeneration.

Science.gov (United States)

Wisse, L E M; Das, S R; Davatzikos, C; Dickerson, B C; Xie, S X; Yushkevich, P A; Wolk, D A

2018-01-01

Suspected non-Alzheimer's pathophysiology (SNAP) is a biomarker driven designation that represents a heterogeneous group in terms of etiology and prognosis. SNAP has only been identified by cross-sectional neurodegeneration measures, whereas longitudinal measures might better reflect "active" neurodegeneration and might be more tightly linked to prognosis. We compare neurodegeneration defined by cross-sectional 'hippocampal volume' only (SNAP/L-) versus both cross-sectional and longitudinal 'hippocampal atrophy rate' (SNAP/L+) and investigate how these definitions impact prevalence and the clinical and biomarker profile of SNAP in Mild Cognitive Impairment (MCI). 276 MCI patients from ADNI-GO/2 were designated amyloid "positive" (A+) or "negative" (A-) based on their florbetapir scan and neurodegeneration 'positive' or 'negative' based on cross-sectional hippocampal volume and longitudinal hippocampal atrophy rate. 74.1% of all SNAP participants defined by the cross-sectional definition of neurodegeneration also met the longitudinal definition of neurodegeneration, whereas 25.9% did not. SNAP/L+ displayed larger white matter hyperintensity volume, a higher conversion rate to dementia over 5 years and a steeper decline on cognitive tasks compared to SNAP/L- and the A- CN group. SNAP/L- had more abnormal values on neuroimaging markers and worse performance on cognitive tasks than the A- CN group, but did not show a difference in dementia conversion rate or longitudinal cognition. Using a longitudinal definition of neurodegeneration in addition to a cross-sectional one identifies SNAP participants with significant cognitive decline and a worse clinical prognosis for which cerebrovascular disease may be an important driver.

Ozil IP torsional mode versus combined torsional/longitudinal microcoaxial phacoemulsification.

Science.gov (United States)

Helvacioglu, Firat; Tunc, Zeki; Yeter, Celal; Oguzhan, Hasan; Sencan, Sadik

2012-01-01

To compare the safety and efficacy of microcoaxial phacoemulsification surgeries performed with the Ozil Intelligent Phaco (IP) torsional mode and combined torsional/longitudinal ultrasound (US) mode using the Infiniti Vision System (Alcon Laboratories). In this prospective randomized comparative study, 60 eyes were assigned to 2.2-mm microcoaxial phacoemulsification using the Ozil IP torsional mode (group 1) or combined torsional/longitudinal US mode (group 2). The primary outcome measures were US time (UST), cumulative dissipated energy (CDE), longitudinal and torsional ultrasound amplitudes, mean operation time, mean volume of balanced salt solution (BSS) used, and surgical complications. Both groups included 30 eyes. Mean UST, CDE, and longitudinal and torsional ultrasound amplitudes in group 1 were 1 minute 15±34.33 seconds, 8.74±5.64, 0.43±0.74, and 25.56±8.56, respectively, and these parameters in group 2 were 1 minute 40±51.44 seconds, 9.28±5.99, 3.64±1.55, and 3.71±1.34, respectively. UST and longitudinal amplitudes were found to be significantly low in group 1 (p<0.001, p<0.001), whereas torsional amplitude was found to be significantly high in this group (p=0.001). Mean volumes of BSS used in groups 1 and 2 were 63.30±18.00 cc and 84.50±28.65 cc, respectively (p=0.001). The Ozil IP torsional mode may provide more effective lens removal than the combined torsional/longitudinal US mode with a lower UST and volume of BSS used.

Dynamics of heavy ion beams during longitudinal compression

International Nuclear Information System (INIS)

Ho, D.D.M.; Bangerter, R.O.; Lee, E.P.; Brandon, S.; Mark, J.W.K.

1987-01-01

Heavy ion beams with initially uniform line charge density can be compressed longitudinally by an order of magnitude in such a way that the compressed beam has uniform line charge density and velocity-tilt profiles. There are no envelope mismatch oscillations during compression. Although the transverse temperature varies along the beam and also varies with time, no substantial longitudinal and transverse emittance growth has been observed. Scaling laws for beam radius and transport system parameters are given

Statistical methods for longitudinal data with agricultural applications

DEFF Research Database (Denmark)

Anantharama Ankinakatte, Smitha

The PhD study focuses on modeling two kings of longitudinal data arising in agricultural applications: continuous time series data and discrete longitudinal data. Firstly, two statistical methods, neural networks and generalized additive models, are applied to predict masistis using multivariate...... algorithm. This was found to compare favourably with the algorithm implemented in the well-known Beagle software. Finally, an R package to apply APFA models developed as part of the PhD project is described...

Longitudinal and bulk viscosities of expanded rubidium

International Nuclear Information System (INIS)

Zaheri, Ali Hossein Mohammad; Srivastava, Sunita; Tankeshwar, K

2003-01-01

First three non-vanishing sum rules for the bulk and longitudinal stress auto-correlation functions have been evaluated for liquid Rb at six thermodynamic states along the liquid-vapour coexistence curve. The Mori memory function formalism and the frequency sum rules have been used to calculate bulk and longitudinal viscosities. The results thus obtained for the ratio of bulk viscosity to shear viscosity have been compared with experimental and other theoretical predictions wherever available. The values of the bulk viscosity have been found to be more than the corresponding values of the shear viscosity for all six thermodynamic states investigated here

Simulation of the longitudinal instabilities of the asymmetric bunches

International Nuclear Information System (INIS)

Dai Jianping; Zhao Zhentang

2002-01-01

The computational model of the code used to simulate the longitudinal instabilities of the asymmetric bunches was introduced. The growth rates of the longitudinal instabilities of the symmetric bunches got by this code were compared with those got by the code ZAP, and they were almost the same. As an example, the simulation results of the BEPC-II were presented

Longitudinal Bunch Position Control for the Super-B Accelerator

International Nuclear Information System (INIS)

Bertsche, Kirk; Rivetta, Claudio; Sullivam, Michael K.; SLAC; Drago, Alessandro; Frascati

2009-01-01

The use of normal conducting cavities and an ion-clearing gap will cause a significant RF accelerating voltage gap transient and longitudinal phase shift of the individual bunches along the bunch train in both rings of the SuperB accelerator. Small relative centroid position shifts between bunches of the colliding beams will have a large adverse impact on the luminosity due to the small β* y at the interaction point (IP). We investigate the possibility of minimizing the relative longitudinal position shift between bunches by reducing the gap transient in each ring and matching the longitudinal bunch positions of the two rings at the IP using feedback/feedforward techniques in the LLRF. The analysis is conducted assuming maximum use of the klystron power installed in the system

Longitudinal Jitter Analysis of a Linear Accelerator Electron Gun

Directory of Open Access Journals (Sweden)

MingShan Liu

2016-11-01

Full Text Available We present measurements and analysis of the longitudinal timing jitter of a Beijing Electron Positron Collider (BEPCII linear accelerator electron gun. We simulated the longitudinal jitter effect of the gun using PARMELA to evaluate beam performance, including: beam profile, average energy, energy spread, and XY emittances. The maximum percentage difference of the beam parameters is calculated to be 100%, 13.27%, 42.24% and 65.01%, 86.81%, respectively. Due to this, the bunching efficiency is reduced to 54%. However, the longitudinal phase difference of the reference particle was 9.89°. The simulation results are in agreement with tests and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

Longitudinal transport measurements in an energy recovery accelerator with triple bend achromat arcs

Directory of Open Access Journals (Sweden)

F. Jackson

2016-12-01

Full Text Available Longitudinal properties of electron bunches (energy spread and bunch length and their manipulation are of importance in free electron lasers (FELs, where magnetic bunch length compression is a common feature of beam transport. Recirculating accelerators and energy recovery linac accelerators (ERLs have been used as FEL drivers for several decades and control of longitudinal beam transport is particularly important in their magnet lattices. We report on measurements of longitudinal transport properties in an ERL-FEL, the ALICE (Accelerators and Lasers in Combined Experiments accelerator at Daresbury Laboratory. ALICE is an energy recovery research accelerator that drives an infrared free electron laser. By measuring the time of arrival of electron bunches, the canonical longitudinal transport quantities were measured in the beam transport and bunch compression sections of the lattice. ALICE includes a four-dipole bunch compression chicane providing fixed longitudinal transport, and triple bend achromat arcs including sextupole magnets where the first and second order longitudinal transport can be adjusted. The longitudinal transport properties in these lattice sections were measured and compared with the theoretical model of the lattice. A reasonable level of agreement has been found. The effect of sextupoles in second order, as well as first order, longitudinal correction is considered, with the measurements indicating the level of alignment of the beam to the center of the sextupole.

Using Facebook to Maximize Follow-Up Response Rates in a Longitudinal Study of Adults Who Use Methamphetamine

OpenAIRE

Bolanos, Franklin; Herbeck, Diane; Christou, Dayna; Lovinger, Katherine; Pham, Aurora; Raihan, Adnan; Rodriguez, Luz; Sheaff, Patricia; Brecht, Mary-Lynn

2012-01-01

This study examines the process and effects of using facebook (FB) to locate and re-contact study participants targeted for follow up in a longitudinal study of adult methamphetamine users (N = 649). A follow-up interview was conducted in 2009–11 approximately 8 years after previous study participation. Our paper describes re-contact efforts involving FB, including IRB regulatory issues and the effectiveness of using FB compared to mailings and phone calls. A total of 48 of the 551 surviving ...

Influence of Asthma on the Longitudinal Trajectories of Cigarette Use Behaviors From Adolescence to Adulthood Using Latent Growth Curve Models

Directory of Open Access Journals (Sweden)

Jisuk Bae

2015-03-01

Full Text Available Objectives: While epidemiologic research indicates that the prevalence of risk-taking behaviors including cigarette smoking among young people with asthma is substantial, the longitudinal patterns of cigarette smoking in this vulnerable population have received little attention. The aim of this study was to evaluate differences in the longitudinal trajectories of cigarette use behaviors from adolescence to adulthood between young people with and without asthma. Methods: Data from the National Longitudinal Study of Adolescent to Adult Health (Add Health during the years 1994 to 1995 (Wave I, adolescence, 2001 to 2002 (Wave III, young adulthood, and 2007 to 2008 (Wave IV, adulthood were analyzed (n=12 244. Latent growth curve models were used to examine the longitudinal trajectories of cigarette use behaviors during the transition to adulthood according to asthma status. Results: Regardless of asthma status, the trajectory means of cigarette use behaviors were found to increase, and then slightly decrease from adolescence to adulthood. In total participants, there were no statistically significant differences in initial levels and changes in cigarette use behaviors according to asthma status. However, in select sex and race subgroups (i.e., females and non-whites, former asthmatics showed greater escalation in cigarette use behaviors than did non-asthmatics or current asthmatics. Conclusions: This study indicated that the changing patterns of cigarette use behaviors during the transition to adulthood among young people with asthma are comparable to or even more drastic than those among young people without asthma.

Learning from Longitudinal Research in Criminology and the Health Sciences

Science.gov (United States)

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…

Longitudinal person-related determinants of physical activity in young adults.

NARCIS (Netherlands)

Uijtdewilligen, L.; Twisk, J.W.R.; Chinapaw, M.J.M.; Koppes, L.L.J.; Mechelen, W. van; Singh, A.S.

2014-01-01

Purpose: This study aimed to examine the longitudinal associations of person-related factors with physical activity (PA) behavior in young adults. Methods: We analyzed longitudinal self-reported time spent in moderate-intensity PA (MPA; 4–7 METs) and vigorous-intensity PA (VPA; >7 METs) from 499

Longitudinal Person-Related Determinants of Physical Activity in Young Adults

NARCIS (Netherlands)

Uijtdewilligen, L.; Twisk, J.W.R.; Chin A Paw, M.J.M.; Koppes, L.L.J.; van Mechelen, W.; Singh, A.S.

2014-01-01

Purpose: This study aimed to examine the longitudinal associations of person-related factors with physical activity (PA) behavior in young adults. Methods: We analyzed longitudinal self-reported time spent in moderate-intensity PA (MPA; 4-7 METs) and vigorous-intensity PA (VPA; >7 METs) from 499

Longitudinal person-related determinants of physical activity in young adults

NARCIS (Netherlands)

Uijtdewilligen, L.; Twisk, J.W.R.; Chinapaw, M.J.M.; Koppes, L.L.J.; Mechelen, W. van; Singh, A.S.

2014-01-01

Purpose: This study aimed to examine the longitudinal associations of person-related factors with physical activity (PA) behavior in young adults. Methods: We analyzed longitudinal self-reported time spent in moderate-intensity PA (MPA; 4-7 METs) and vigorous-intensity PA (VPA; >7 METs) from 499

A longitudinal study

OpenAIRE

Kristen, Astrid

2010-01-01

Does playing violent video games increase aggressive behavior over time or is it aggressive children who increasingly seek out (and play) these violent video games? To study such long-term effects a longitudinal design is necessary. Within a field study in a large German city (Kinder, Computer, Hobby, Lernen – KUHL, Freie Universtität Berlin) about 115 elementary school boys attending in the beginning (t1) classrooms of the third and fourth grade and twelve months later (t2) classrooms of the...

Nonlinear correction to the longitudinal structure function at small x

International Nuclear Information System (INIS)

Boroun, G.R.

2010-01-01

We computed the longitudinal proton structure function F L , using the nonlinear Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (NLDGLAP) evolution equation approach at small x. For the gluon distribution, the nonlinear effects are related to the longitudinal structure function. As the very small-x behavior of the gluon distribution is obtained by solving the Gribov, Levin, Ryskin, Mueller and Qiu (GLR-MQ) evolution equation with the nonlinear shadowing term incorporated, we show that the strong rise that corresponds to the linear QCD evolution equations can be tamed by screening effects. Consequently, the obtained longitudinal structure function shows a tamed growth at small x. We computed the predictions for all details of the nonlinear longitudinal structure function in the kinematic range where it has been measured by the H1 Collaboration and made comparisons with the computation by Moch, Vermaseren and Vogt at the second order with input data from the MRST QCD fit. (orig.)

JUICE EXTRACTION FOR TOTAL SOLUBLE SOLIDS CONTENT DETERMINATION IN MELON

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Paulo Sérgio Lima e Silva

2006-01-01

Full Text Available The total soluble solids content (TSSC shows high positive correlation with sugars content, and therefore is generally accepted as an important quality trait of fruits. In melon, this evaluation is usually done by grinding a slice of the fruit's pulp in a household food processor, straining the ground material and then proceeding the TSSC determination in the resulting juice. This evaluation is labor-intensive and takes a long time to complete. An alternative process was delineated for obtaining the juice: the pulp of the fruit slice would be transversally cut one or more times, and longitudinally pressed by hand to obtain the juice. The objective of this work was to compare processes for obtaining juice to evaluate TSSC in melons. Fifty, 15, and 15 fruits of the Galia, Yellow, and Cantaloupe type melons were evaluated, respectively. Each fruit was considered as a block, and was longitudinally split into six fractions with similar sizes, which corresponded to the plots. The following treatments were evaluated: fraction without cuts, fractions with one, three, five, or seven transversal cuts, and the fraction treated by the conventional process. It was concluded that the procedure by which the melon slices of Galia, Yellow and Cantaloupe types are pressed for obtaining the juice to evaluate TSSC can overestimate this content. This would probably be due to the fact that the most internal section of the mesocarp presents greater TSSC than the portions closer to the epicarp.

Attitudes as mediators of the longitudinal association between alcohol advertising and youth drinking.

Science.gov (United States)

Morgenstern, Matthis; Isensee, Barbara; Sargent, James D; Hanewinkel, Reiner

2011-07-01

To test the hypothesis that changes in alcohol-related attitudes and expectancies mediate the effect of alcohol advertising on youth drinking. Longitudinal survey with a 9-month interval. Twenty-nine public schools in 3 German states. A total of 2130 sixth- to eighth-grade students (age range, 11-17 years; mean, 12.2 years) who were nondrinkers at baseline. Exposure to alcohol and nonalcohol advertising was measured at baseline with masked images of 17 commercial advertisements with all brand information digitally removed; students indicated contact frequency and brand names. Positive attitudes toward alcohol, current alcohol use, lifetime binge drinking. A total of 581 of the students (28%) started to drink alcohol during the observation period. Alcohol use initiation was positively related to baseline alcohol advertisement exposure. This effect of alcohol advertisement exposure on alcohol use was partially mediated by a change in alcohol-related attitudes, which explained about 35% of the total effect after controlling for baseline covariates and exposure to other advertising contents. The analysis revealed similar results for binge-drinking initiation. More favorable attitudes about alcohol may be one path through which alcohol advertising exerts behavioral influence.

Qualità totale e mobilità totale Total Quality and Total Mobility

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Giuseppe Trieste

2010-05-01

Full Text Available FIABA ONLUS (Italian Fund for Elimination of Architectural Barriers was founded in 2000 with the aim of promoting a culture of equal opportunities and, above all, it has as its main goal to involve public and private institutions to create a really accessible and usable environment for everyone. Total accessibility, Total usability and Total mobility are key indicators to define quality of life within cities. A supportive environment that is free of architectural, cultural and psychological barriers allows everyone to live with ease and universality. In fact, people who access to goods and services in the urban context can use to their advantage time and space, so they can do their activities and can maintain relationships that are deemed significant for their social life. The main aim of urban accessibility is to raise the comfort of space for citizens, eliminating all barriers that discriminate people, and prevent from an equality of opportunity. “FIABA FUND - City of ... for the removal of architectural barriers” is an idea of FIABA that has already affected many regions of Italy as Lazio, Lombardy, Campania, Abruzzi and Calabria. It is a National project which provides for opening a bank account in the cities of referring, in which for the first time, all together, individuals and private and public institutions can make a donation to fund initiatives for the removal of architectural barriers within its own territory for a real and effective total accessibility. Last February the fund was launched in Rome with the aim of achieving a Capital without barriers and a Town European model of accessibility and usability. Urban mobility is a prerequisite to access to goods and services, and to organize activities related to daily life. FIABA promotes the concept of sustainable mobility for all, supported by the European Commission’s White Paper. We need a cultural change in management and organization of public means, which might focus on

Longitudinal tracking with phase and amplitude modulated rf

International Nuclear Information System (INIS)

Caussyn, D.D.; Ball, M.; Brabson, B.

1993-06-01

Synchrotron motion was induced by phase shifting the rf of the Indiana University Cyclotron Facility (IUCF) cooler-synchrotron. The resulting coherent-bunch motion was tracked in longitudinal phase space for as many as 700,000 turns, or for over 350 synchrotron oscillations. Results of recent experimental studies of longitudinal motion in which the rf phase and amplitude were harmonically modulated are also presented. Comparisons of experimental data with numerical simulations, assuming independent particle motion, are made. Observed multiparticle effects are also discussed

General self-efficacy and posttraumatic stress after a natural disaster: a longitudinal study.

Science.gov (United States)

Nygaard, Egil; Hussain, Ajmal; Siqveland, Johan; Heir, Trond

2016-04-06

Self-efficacy may be an important factor in individuals' recovery from posttraumatic stress reactions after a natural disaster. However, few longitudinal studies have investigated whether self-efficacy predicts the course of posttraumatic recovery beyond lower initial levels of distress. The purpose of the present study was to investigate whether general self-efficacy is related to recovery from posttraumatic stress reactions from a longitudinal perspective. A total of 617 Norwegians exposed to the 2004 Southeast Asian tsunami completed self-report questionnaires measuring their level of disaster exposure and general self-efficacy at 6 months and posttraumatic stress reactions 6 months and 2 years post-disaster. Predictors of changes in posttraumatic stress reactions were analyzed with multivariate mixed effects models. Self-efficacy at 6 months post-disaster was unrelated to trauma exposure and inversely related to posttraumatic stress reactions at 6 months and 2 years post-disaster. However, self-efficacy was not related to recovery from posttraumatic stress reactions between 6 months and 2 years post-disaster. In conclusion, general self-efficacy is related to lower levels of posttraumatic stress reactions in the first months after a disaster but does not appear to be related to improved recovery rates over the longer term.

Baseline prevalence and longitudinal evolution of non-motor symptoms in early Parkinson's disease: the PPMI cohort.

Science.gov (United States)

Simuni, Tanya; Caspell-Garcia, Chelsea; Coffey, Christopher S; Weintraub, Daniel; Mollenhauer, Brit; Lasch, Shirley; Tanner, Caroline M; Jennings, Danna; Kieburtz, Karl; Chahine, Lana M; Marek, Kenneth

2018-01-01

To examine the baseline prevalence and longitudinal evolution in non-motor symptoms (NMS) in a prospective cohort of, at baseline, patients with de novo Parkinson's disease (PD) compared with healthy controls (HC). Parkinson's Progression Markers Initiative (PPMI) is a longitudinal, ongoing, controlled study of de novo PD participants and HC. NMS were rated using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I score and other validated NMS scales at baseline and after 2 years. Biological variables included cerebrospinal fluid (CSF) markers and dopamine transporter imaging. 423 PD subjects and 196 HC were enrolled and followed for 2 years. MDS-UPDRS Part I total mean (SD) scores increased from baseline 5.6 (4.1) to 7.7 (5.0) at year 2 in PD subjects (pbaseline NMS score was associated with female sex (p=0.008), higher baseline MDS-UPDRS Part II scores (pbaseline. There was no association with the dose or class of dopaminergic therapy. This study of NMS in early PD identified clinical and biological variables associated with both baseline burden and predictors of progression. The association of a greater longitudinal increase in NMS with lower baseline Aβ1-42 level is an important finding that will have to be replicated in other cohorts. ClinicalTrials.gov identifier: NCT01141023. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Incapacidad laboral total

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Orlando Díaz Tabares

1997-04-01

Full Text Available Se realizó un estudio longitudinal, descriptivo y retrospectivo con el objetivo de conocer el comportamiento de la incapacidad permanente para el trabajo en el municipio "San Cristóbal" durante el decenio 1982-1991, y se aplicó el método de encuesta por el que se recogieron datos que fueron extraídos del modelo oficial de peritaje médico laboral y de la entrevista con el peritado. Los resultados fueron plasmados en tablas de contingencias donde se relacionan las variables por cada año estudiado, y se aplicó la prueba estadística de chi cuadrado. El número de individuos dictaminados con incapacidad laboral total fue de 693; predominó en reportes el año 1988 con 114 casos y muy discretamente el sexo femenino sobre el masculino, el grupo etáreo de 45 a 54 años con 360 casos y la artrosis como entidad valorada por ortopedia, con análisis estadísticos significativos. No resultó estadísticamente significativo, el predominio de la hipertensión arterial sistémica entre las entidades valoradas por la especialidad de medicina interna como causas de incapacidad laboral. Fue muy significativa la variación del número de dictaminados por la comisión en cada uno de los años estudiados y que el porcentaje de ellos que se encontraban realizando trabajos que demandan esfuerzo físico de moderado a intenso al momento de aplicar la encuesta, ascendió al 64,9.A longitudinal, descriptive and retrospective study was conducted in order to know the behavior of permanent labor disability at the municipality of San Cristóbal during 1982-1991. A survey was done to collect data taken from the official model of medical inspections and from the interview with the disabled worker. The results were shown in contingency tables where the variables are related by every year studied. The chi square statistical test was applied. The number of individuals with labor disability was 693. As for reports, the year 1988 predominated with 114. There was a discreet

A Six-Year Longitudinal Study of Consumption of Pornographic Materials in Chinese Adolescents in Hong Kong.

Science.gov (United States)

Shek, Daniel T L; Ma, Cecilia M S

2016-02-01

Using longitudinal data collected over 6 years, consumption of pornographic materials in adolescents in Hong Kong and the related demographic and psychosocial correlates were examined in this study. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: A longitudinal research design with 6 waves of data was used to examine consumption of pornographic materials in high school students. A total of 3291 high school students from 28 schools responded to the questionnaire at wave 1. Consumption of online pornography was higher than traditional pornography. There was an increase in consumption of pornographic materials in the high school years. Gender, family functioning, and positive youth development were related to the initial status of pornography consumption. Besides, gender, family intactness and positive youth development predicted rates of change in consumption of pornographic material over time. The present findings showed that gender, family functioning, and positive youth development are significant predictors for pornography consumption in Chinese adolescents. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Single bunch fast longitudinal instability

International Nuclear Information System (INIS)

Wang, J.M.; Pellegrini, C.

1979-01-01

Single bunch longitudinal instability producing an increase of the bunch area have been observed in proton synchrotron and storage rings. Signals at microwave frequencies are observed during the bunch blow-up and because of this the effect has been called the microwave instability. A similar increase in bunch area is observed also in electron storage rings, where it is usually referred to as the bunch lengthening effect. This paper is an attempt to obtain a more general theory of this effect. Here we describe the model used and the method of calculation, together with some general results. More detailed results will be given in another paper. The main result is the derivation of a condition for the existence of a fast longitudinal bunch blow-up. This condition is a generalized threshold formula, showing explicitly the dependence on the bunch energy spread and length. This condition is qualitatively in agreement with Boussard's suggestion

Longitudinal emittance blowup in the large hadron collider

CERN Document Server

Baudrenghien, P

2013-01-01

The Large Hadron Collider (LHC) relies on Landau damping for longitudinal stability. To avoid decreasing the stability margin at high energy, the longitudinal emittance must be continuously increased during the acceleration ramp. Longitudinal blowup provides the required emittance growth. The method was implemented through the summer of 2010. Band-limited RF phase-noise is injected in the main accelerating cavities during the whole ramp of about 11min. Synchrotron frequencies change along the energy ramp, but the digitally created noise tracks the frequency change. The position of the noise-band, relative to the nominal synchrotron frequency, and the bandwidth of the spectrum are set by pre-defined constants, making the diffusion stop at the edges of the demanded distribution. The noise amplitude is controlled by feedback using the measurement of the average bunch length. This algorithm reproducibly achieves the programmed bunch length of about 1.2ns, at flat top with low bunch-to-bunch scatter and provides a...

A Semiparametric Marginalized Model for Longitudinal Data with Informative Dropout

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Mengling Liu

2012-01-01

Full Text Available 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.

Sequential Progressions in a Theory-of-Mind Scale: Longitudinal Perspectives

Science.gov (United States)

Wellman, Henry M.; Fang, Fuxi; Peterson, Candida C.

2011-01-01

Consecutive retestings of 92 U.S. preschoolers (n = 30), Chinese preschoolers (n = 31), and deaf children (n = 31) examined whether the sequences of development apparent in cross-sectional results with a theory-of-mind scale also appeared in longitudinal assessment. Longitudinal data confirmed that theory-of-mind progressions apparent in…

Boosting joint models for longitudinal and time-to-event data

DEFF Research Database (Denmark)

Waldmann, Elisabeth; Taylor-Robinson, David; Klein, Nadja

2017-01-01

Joint models for longitudinal and time-to-event data have gained a lot of attention in the last few years as they are a helpful technique clinical studies where longitudinal outcomes are recorded alongside event times. Those two processes are often linked and the two outcomes should thus be model...

Nonlinear Cascade Strategy for Longitudinal Control of Electric Vehicle.

Science.gov (United States)

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.

Structure functions of longitudinal virtual photons at low virtualities

International Nuclear Information System (INIS)

Ioffe, B.L.; Shushpanov, I.A.

1996-01-01

The structure functions F L 1 and F L 2 of longitudinal virtual photons at low virtualities are calculated in the framework of chiral perturbation theory (ChPT) in the zero and first order of ChPT. It is assumed that the virtuality of a target longitudinal photon p 2 is much less than the virtuality of the hard projectile photon Q 2 and both are less than the characteristic ChPT scale. In this approximation the structure functions are determined by the production of two pions in γγ collisions. The numerical results for F L 2 and F L 1 are presented (the upper index refers to the longitudinal polarization of the virtual target photon). The possibilities of measurements of these structure functions are briefly discussed. copyright 1996 The American Physical Society

Longitudinal Associations of Phospholipid and Cholesteryl Ester Fatty Acids With Disorders Underlying Diabetes.

Science.gov (United States)

Johnston, Luke W; Harris, Stewart B; Retnakaran, Ravi; Zinman, Bernard; Giacca, Adria; Liu, Zhen; Bazinet, Richard P; Hanley, Anthony J

2016-06-01

Specific serum fatty acid (FA) profiles predict the development of incident type 2 diabetes; however, limited longitudinal data exist exploring their role in the progression of insulin sensitivity (IS) and β-cell function. To examine the longitudinal associations of the FA composition of serum phospholipid (PL) and cholesteryl ester (CE) fractions with IS and β-cell function over 6 years. The Prospective Metabolism and Islet Cell Evaluation (PROMISE) cohort is a longitudinal observational study, with clinic visits occurring every 3 years. Three visits have been completed, totaling 6 years of follow-up. Individuals (n = 477) at risk for diabetes recruited from the general population in London and Toronto, Canada. Values from an oral glucose tolerance test were used to compute 1/HOMA-IR and the Matsuda index for IS, the insulinogenic index over HOMA-IR, and the insulin secretion-sensitivity index-2 for β-cell function. Thin-layer chromatograph and gas chromatograph quantified FA. Generalized estimating equations were used for the analysis. IS and β-cell function declined by 8.3-19.4% over 6 years. In fully adjusted generalized estimating equation models, PL cis-vaccenate (18:1n-7) was positively associated with all outcomes, whereas γ-linolenate (GLA; 18:3n-6) and stearate (18:0) were negatively associated with IS. Tests for time interactions revealed that PL eicosadienoate (20:2n-6) and palmitate (16:0) and CE dihomo-γ-linolenate (20:3n-6), GLA, and palmitate had stronger associations with the outcomes after longer follow-up. In a Canadian population at risk for diabetes, we found that higher PL stearate and GLA and lower cis-vaccenic acid predicted consistently lower IS and β-cell function over 6 years.

Multilevel Cross-Dependent Binary Longitudinal Data

KAUST Repository

Serban, Nicoleta; Staicu, Ana-Maria; Carroll, Raymond J.

2013-01-01

processes describing the within- and between-variability, and describing the cross-dependence of the repeated longitudinal measurements. We estimate the model components without employing mixed-effects modeling but assuming an approximation to the logistic

Distribution-free Inference of Zero-inated Binomial Data for Longitudinal Studies.

Science.gov (United States)

He, H; Wang, W J; Hu, J; Gallop, R; Crits-Christoph, P; Xia, Y L

2015-10-01

Count reponses with structural zeros are very common in medical and psychosocial research, especially in alcohol and HIV research, and the zero-inflated poisson (ZIP) and zero-inflated negative binomial (ZINB) models are widely used for modeling such outcomes. However, as alcohol drinking outcomes such as days of drinkings are counts within a given period, their distributions are bounded above by an upper limit (total days in the period) and thus inherently follow a binomial or zero-inflated binomial (ZIB) distribution, rather than a Poisson or zero-inflated Poisson (ZIP) distribution, in the presence of structural zeros. In this paper, we develop a new semiparametric approach for modeling zero-inflated binomial (ZIB)-like count responses for cross-sectional as well as longitudinal data. We illustrate this approach with both simulated and real study data.

Morbidade em creche de Brasília: estudo longitudinal de incidência de enfermidades no ano de 1977 Morbidity in a Brasilia day care center: a longitudinal study of disease incidence in 1977

Directory of Open Access Journals (Sweden)

Ana Maria Low

1980-12-01

Full Text Available Foi feito estudo longitudinal de morbidade em creche de Brasília (Brasil freqüentada por crianças com bom estado nutricional. Foram admitidas na creche durante o ano de 1977 o total de 67 crianças (34 do sexo masculino e 33 do sexo feminino, com idade entre 3 e 21 meses. Infecções de vias aéreas superiores (25,4%, diarréia (23,6% e febre não esclarecida (18,4% representaram dois terços dos diagnósticos. A seguir, em ordem de freqüência, apareceram conjuntivite (15,5%, viroses da infância (7,9%, doenças de pele (3,8%, pequenos acidentes (2,6%, hepatite (2,6% e meningococcemia (0,3%. Houve um total de 343 episódios agudos, dando uma taxa de incidência de 14 enfermidades por criança por ano, independente de sexo e idade.A longitudinal morbidity study was carried out in a day care center in Brasilia (Brazil on a sample of 67 (34 male and 33 female, 3 to 21 months of age well-fed children from middle-class families. A pediatrician was on duty daily in the center. The incidence of disease was: upper respiratory, 25.4%; diarrhea, 23.6%; and undetermined fever, 18.4%. These represented 2/3 of the diagnoses. The other diseases found (and here listed in order of frequency were: conjunctivitis, 15.5%; childhood infections, 7.9%; skin diseases, 3.8%; accidents, 2.6%; hepatitis, 2.6%; and meningitis, 0.3%. There were a total of 343 acute illnesses, giving a mean incidence rate of 14 illnesses per child per year, independent of sex and age. Perhaps the incidence of illnesses would have been lower if the children had not been attending the center, a natural factor in the dissemination of communicable diseases.

Longitudinal permittivity of a toroidal plasma near rational surfaces

International Nuclear Information System (INIS)

Nekrasov, F.M.

1990-01-01

A quite simple analytical formula for longitudinal permittivity, suitable for numerical processing on a computer, is determined. On the basis of a Fourier representation a poloidal angle a compact expression for the imaginary part of longitudinal permittivity near rational surfaces (m+nq=0) at an arbitrary relation between the bounce frequency and excited wave frequency is determined. A strongly magnetized collisionless plasma in the weak toroidality approximation is considered

Causal mediation analysis for longitudinal data with exogenous exposure

OpenAIRE

Bind, M.-A. C.; Vanderweele, T. J.; Coull, B. A.; Schwartz, J. D.

2015-01-01

Mediation analysis is a valuable approach to examine pathways in epidemiological research. Prospective cohort studies are often conducted to study biological mechanisms and often collect longitudinal measurements on each participant. Mediation formulae for longitudinal data have been developed. Here, we formalize the natural direct and indirect effects using a causal framework with potential outcomes that allows for an interaction between the exposure and the mediator. To allow different type...

Longitudinal waves and a beam instability in a relativistic anisotropic plasma

International Nuclear Information System (INIS)

Onishchenko, O.G.

1981-01-01

Dispersion relations are derived for longitudinal waves in a relativistic plasma with an arbitrary anisotropic particle distribution function. Longitudinal waves with phase velocity lower than the speed of light are shown to exist in such a plasma. The damping rate of longitudinal waves due to the Cerenkov interaction with plasma particles is derived for such a plasma. The instability of a beam of high-energy particles in such a plasma is studied. As the anisotropy of an ultrarelativistic plasma becomes less pronounced, the maximum hydrodynamic growth rate decreases

Longitudinal Trajectories of Perceived Body Weight: Adolescence to Early Adulthood

Science.gov (United States)

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…

Accounting for dropout reason in longitudinal studies with nonignorable dropout.

Science.gov (United States)

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

2017-08-01

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

Adolescent psychosocial development: A review of longitudinal models and research.

Science.gov (United States)

Meeus, Wim

2016-12-01

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 developmental domains; (2) heterogeneous continuity of personal relationships; (3) good goes together with good, and bad with bad, across time in adolescence; (4) parents transmit values and behaviors to their adolescent children over time; (5) adolescent psychopathology leads to erosion of personal relationships with parents and peers; (6) adolescent psychopathology prevents adolescent independence from parents; (7) parental interference in personal issues of adolescents has counterproductive effects over time; (8) mood variability and (social and personal) uncertainty are mechanisms that maintain psychopathology in adolescence. Principles of life span developmental psychology are used to discuss adolescent maturation, and a developmental contextual perspective is used to discuss links between the various developmental patterns. Strengths and limitations of the various longitudinal models, and links between longitudinal and experimental research are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Within-subject template estimation for unbiased longitudinal image analysis.

Science.gov (United States)

Reuter, Martin; Schmansky, Nicholas J; Rosas, H Diana; Fischl, Bruce

2012-07-16

Longitudinal image analysis has become increasingly important in clinical studies of normal aging and neurodegenerative disorders. Furthermore, there is a growing appreciation of the potential utility of longitudinally acquired structural images and reliable image processing to evaluate disease modifying therapies. Challenges have been related to the variability that is inherent in the available cross-sectional processing tools, to the introduction of bias in longitudinal processing and to potential over-regularization. In this paper we introduce a novel longitudinal image processing framework, based on unbiased, robust, within-subject template creation, for automatic surface reconstruction and segmentation of brain MRI of arbitrarily many time points. We demonstrate that it is essential to treat all input images exactly the same as removing only interpolation asymmetries is not sufficient to remove processing bias. We successfully reduce variability and avoid over-regularization by initializing the processing in each time point with common information from the subject template. The presented results show a significant increase in precision and discrimination power while preserving the ability to detect large anatomical deviations; as such they hold great potential in clinical applications, e.g. allowing for smaller sample sizes or shorter trials to establish disease specific biomarkers or to quantify drug effects. Copyright © 2012 Elsevier Inc. All rights reserved.

LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

Energy Technology Data Exchange (ETDEWEB)

Luna-Cardozo, M. [Instituto de Astronomia y Fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Verth, G. [School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom); Erdelyi, R., E-mail: mluna@iafe.uba.ar, E-mail: robertus@sheffield.ac.uk, E-mail: gary.verth@northumbria.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

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.

Joint Models for Longitudinal and Time-to-Event Data With Applications in R

CERN Document Server

Rizopoulos, Dimitris

2012-01-01

In longitudinal studies it is often of interest to investigate how a marker that is repeatedly measured in time is associated with a time to an event of interest, e.g., prostate cancer studies where longitudinal PSA level measurements are collected in conjunction with the time-to-recurrence. Joint Models for Longitudinal and Time-to-Event Data: With Applications in R provides a full treatment of random effects joint models for longitudinal and time-to-event outcomes that can be utilized to analyze such data. The content is primarily explanatory, focusing on applications of joint modeling, but

The longitudinal relation between smoking and muscle strength in healthy adults

NARCIS (Netherlands)

Kok, Maarten O; Hoekstra, T.; Twisk, Jos W R

2012-01-01

AIM: To assess longitudinally whether smoking tobacco is related to muscle strength in healthy adults and to assess the influence of lifestyle covariates on this relation. METHODS: Data were obtained from the observational Amsterdam Growth and Health Longitudinal Study, with four repeated

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

Science.gov (United States)

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;…

Intraoperative mapping of language functions: a longitudinal neurolinguistic analysis.

Science.gov (United States)

Ilmberger, Josef; Ruge, Maximilian; Kreth, Friedrich-Wilhelm; Briegel, Josef; Reulen, Hans-Juergen; Tonn, Joerg-Christian

2008-10-01

This prospective longitudinally designed study was conducted to evaluate language functions pre- and postoperatively in patients who underwent microsurgical treatment of tumors in close proximity to or within language areas and to detect those patients at risk for a postoperative aphasic disturbance. Between 1991 and 2005, 153 awake craniotomies with subsequent cortical mapping of language functions were performed in 149 patients. Language functions were assessed using a standardized test battery. Risk factors were obtained from multivariate logistic regression models. Language mapping was able to be performed in all patients, and complete tumor resection was achieved in 48.4%. Within 21 days after surgery a new language deficit (aphasic disturbance) was observed in 41 (32%) of the 128 cases without preoperative deficits. There were a total of 60 cases involving postoperative aphasic disturbances, including cases both with and without preoperative disturbances. Risk factors for postoperative aphasic disturbance were preoperative aphasia (planguage-positive sites within the tumor (planguage disturbances. A total of 17.6% of all cases demonstrated new postoperative language disturbances after 7 months. Risk factors for persistent aphasic disturbance were increased age (>40 years, planguage-relevant areas intraoperatively, even when they are located within the tumor. New postoperative deficits resolve in the majority of patients, which may be a result of cortical mapping as well as functional reorganization.

Longitudinal analysis of mouse SDOCT volumes

Science.gov (United States)

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.

Elastography for Thyroid Nodules: The Comparison of Diagnostic Performance on Transverse and Longitudinal Planes

International Nuclear Information System (INIS)

Moon, Hee Jung; Kwak, Jin Young; Kim, Eun Kyung

2012-01-01

To evaluate the diagnostic performance of elastography for thyroid nodules on the transverse and longitudinal planes. Gray scale ultrasonography (US), elastography on trans- verse and longitudinal planes, and fine needle aspiration biopsy for 78 thyroid nodules (malignant: 34 cases, benign: 44 cases) were performed. According to the Asteria criteria of elastography, scores 1 and 2 were classified as probably benign and scores 3 and 4 were classified as suspicious. Strain ratios on transverse and longitudinal planes were measured. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and Az value (under the receiver operating characteristics curve) of elastography on transverse and longitudinal planes were calculated and compared. Scores 3 and 4 were more frequently seen in malignant nodules on the longitudinal plane (p value = 0.007), but not significantly seen on the transverse plane (p value = 0.160). Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and the Az value of elastography on the longitudinal plane were higher than those on the transverse plane, although Az values on the transverse and longtudinal planes were not statistically significant. Diagnostic performance of thyroid elastography, especially sensitivity, were higher on the longitudinal plane than the transverse plane

Geometrical features in longitudinal sputtering hollow cathode discharges for laser applications

NARCIS (Netherlands)

Mihailova, D.B.; Dijk, van J.; Hagelaar, G.J.M.; Karatodorov, S.; Zahariev, P.; Grozeva, M.; Mullen, van der J.J.A.M.

2012-01-01

Longitudinal sputtering hollow cathode discharge (HCD) used as active medium for lasing is studied by means of numerical modelling. Due to the longitudinal non-uniformities of the discharge, the laser operation could be strongly affected. The non-uniformity of the discharge is mainly influenced by

Development of a longitudinal feedback cavity for the beam feedback system

International Nuclear Information System (INIS)

Huang Gang; Chen Huaibi; Huang Wenhui; Tong Dechun; Lin Yuzheng; Zhao Zhentang

2003-01-01

Longitudinal beam feedback system is widely used to damp coupling bunch instability. Kicker is one of the key components of the longitudinal feedback system. A prototype cavity of longitudinal feedback kicker is developed according to the parameter of BEPC II. The usage of nose cone in the kicker design increased the shunt impedance. In order to avoid the extra tapper in the storage ring, the racetrack shape beam pipe is applied in the kicker. The impedance and the bandwidth of the kicker is measured by the coaxial line impedance measurement platform and the result achieved the design goals

Longitudinal in vivo MR imaging of live earthworms.

Science.gov (United States)

Budán, Ferenc; Kovács, Noémi; Engelmann, Péter; Horváth, Ildikó; Veres, Dániel S; Németh, Péter; Szigeti, Krisztián; Máthé, Domokos

2014-11-01

Earthworm (Oligochaeta, Lumbricidae) species are used widely in eco-toxicological tests especially with contaminated soils. These long-term tests are reliable, but a high sample size is needed. Magnetic resonance imaging (MRI) can produce fast, robust, sensitive, and longitudinal morphological results using a small sample size. Performing longitudinal in vivo examinations of earthworms using MRI requires the need for anesthetics to completely avoid earthworm's moving. Our goal was to develop a simple and non-invasive method to anesthetize earthworms for in vivo longitudinal imaging studies. We investigated a number of different anesthesia methods and found that propan-2-ol and its vapor was optimal. We used a commercial sequential nanoScan® PET/MRI system (Mediso Ltd, Hungary, Budapest) to explore feasibility of MR imaging in immobilized earthworms. It was possible to visualize via micro MRI the brain, gastrointestinal tract, seminal vesicles, calciferous gland (Morren gland), and main blood vessels of the circulatory system. Our findings show the possibilities to examine changes in morphology using MRI of certain organs using a reversible, long-term immobilization method. © 2014 Wiley Periodicals, Inc.

Callosal tissue loss parallels subtle decline in psychomotor speed. A longitudinal quantitative MRI study. The LADIS Study

DEFF Research Database (Denmark)

Jokinen, Hanna; Frederiksen, Kristian S; Garde, Ellen

2012-01-01

in a compound measure of cognitive speed and motor control, but not in those of executive functions, memory, or global cognitive function. Total CC area and midbody remained significant predictors of speed also after adjusting for baseline WML volume, WML progression, and global brain atrophy. However......, the relationship between anterior CC and speed performance was mediated by WML volume. In conclusion, the overall and regional rate of CC tissue loss parallels longitudinal slowing of psychomotor performance. The adverse effect of CC tissue loss on psychomotor function may be driven by altered interhemispheric...

High peer popularity longitudinally predicts adolescent health risk behavior, or does it?: an examination of linear and quadratic associations.

Science.gov (United States)

Prinstein, Mitchell J; Choukas-Bradley, Sophia C; Helms, Sarah W; Brechwald, Whitney A; Rancourt, Diana

2011-10-01

In contrast to prior work, recent theory suggests that high, not low, levels of adolescent peer popularity may be associated with health risk behavior. This study examined (a) whether popularity may be uniquely associated with cigarette use, marijuana use, and sexual risk behavior, beyond the predictive effects of aggression; (b) whether the longitudinal association between popularity and health risk behavior may be curvilinear; and (c) gender moderation. A total of 336 adolescents, initially in 10-11th grades, reported cigarette use, marijuana use, and number of sexual intercourse partners at two time points 18 months apart. Sociometric peer nominations were used to examine popularity and aggression. Longitudinal quadratic effects and gender moderation suggest that both high and low levels of popularity predict some, but not all, health risk behaviors. New theoretical models can be useful for understanding the complex manner in which health risk behaviors may be reinforced within the peer context.

Biomarker clusters are differentially associated with longitudinal cognitive decline in late midlife

Science.gov (United States)

Racine, Annie M.; Koscik, Rebecca L.; Berman, Sara E.; Nicholas, Christopher R.; Clark, Lindsay R.; Okonkwo, Ozioma C.; Rowley, Howard A.; Asthana, Sanjay; Bendlin, Barbara B.; Blennow, Kaj; Zetterberg, Henrik; Gleason, Carey E.; Carlsson, Cynthia M.

2016-01-01

The ability to detect preclinical Alzheimer’s disease is of great importance, as this stage of the Alzheimer’s continuum is believed to provide a key window for intervention and prevention. As Alzheimer’s disease is characterized by multiple pathological changes, a biomarker panel reflecting co-occurring pathology will likely be most useful for early detection. Towards this end, 175 late middle-aged participants (mean age 55.9 ± 5.7 years at first cognitive assessment, 70% female) were recruited from two longitudinally followed cohorts to undergo magnetic resonance imaging and lumbar puncture. Cluster analysis was used to group individuals based on biomarkers of amyloid pathology (cerebrospinal fluid amyloid-β42/amyloid-β40 assay levels), magnetic resonance imaging-derived measures of neurodegeneration/atrophy (cerebrospinal fluid-to-brain volume ratio, and hippocampal volume), neurofibrillary tangles (cerebrospinal fluid phosphorylated tau181 assay levels), and a brain-based marker of vascular risk (total white matter hyperintensity lesion volume). Four biomarker clusters emerged consistent with preclinical features of (i) Alzheimer’s disease; (ii) mixed Alzheimer’s disease and vascular aetiology; (iii) suspected non-Alzheimer’s disease aetiology; and (iv) healthy ageing. Cognitive decline was then analysed between clusters using longitudinal assessments of episodic memory, semantic memory, executive function, and global cognitive function with linear mixed effects modelling. Cluster 1 exhibited a higher intercept and greater rates of decline on tests of episodic memory. Cluster 2 had a lower intercept on a test of semantic memory and both Cluster 2 and Cluster 3 had steeper rates of decline on a test of global cognition. Additional analyses on Cluster 3, which had the smallest hippocampal volume, suggest that its biomarker profile is more likely due to hippocampal vulnerability and not to detectable specific volume loss exceeding the rate of normal

Regional gray matter volume increases following 7days of voluntary wheel running exercise: a longitudinal VBM study in rats.

Science.gov (United States)

Sumiyoshi, Akira; Taki, Yasuyuki; Nonaka, Hiroi; Takeuchi, Hikaru; Kawashima, Ryuta

2014-09-01

The effects of physical exercise on brain morphology in rodents have been well documented in histological studies. However, to further understand when and where morphological changes occur in the whole brain, a noninvasive neuroimaging method allowing an unbiased, comprehensive, and longitudinal investigation of brain morphology should be used. In this study, we investigated the effects of 7days of voluntary wheel running exercise on regional gray matter volume (rGMV) using longitudinal voxel-based morphometry (VBM) in rats. Eighteen pairs of adult male naïve Wistar rats were randomized to the exercise or control condition (one rat for each condition from each pair). Each rat was scanned in a 7.0-T MRI scanner at three time points: before exercise, after 7days of exercise, and after 7days of follow-up. The T2-weighted MRI images were segmented using the rat brain tissue priors that were recently published by our laboratory, and the intra- and inter-subject template creation steps were followed. Longitudinal VBM analysis revealed significant increases in rGMV in the motor, somatosensory, association, and visual cortices in the exercise group. Among these brain regions, rGMV changes in the motor cortex were positively correlated with the total distance that was run during the 7days of exercise. In addition, the effects of 7days of exercise on rGMV persisted after 7days of follow-up. These results support the utility of a longitudinal VBM study in rats and provide new insights into experience-dependent structural brain plasticity in naïve adult animals. Copyright © 2014 Elsevier Inc. All rights reserved.

Longitudinal tire force estimation based on sliding mode observer

Energy Technology Data Exchange (ETDEWEB)

El Hadri, A.; Cadiou, J.C.; M' Sirdi, N.K. [Versailles Univ., Paris (France). Lab. de Robotique; Beurier, G.; Delanne, Y. [Lab. Central des Ponts, Centre de Nantes (France)

2001-07-01

This paper presents an estimation method for vehicle longitudinal dynamics, particularly the tractive/braking force. The estimation can be used to detect a critical driving situation to improve security. It can be used also in several vehicle control systems. The main characteristics of the vehicle longitudinal dynamics were taken into account in the model used to design an observer and computer simulations. The state variables are the angular wheel velocity, vehicle velocity and the longitudinal tire force. The proposed differential equation of the tractive/braking force is derived using the concept of relaxation length. The observer designed is based on the sliding mode approach using only the angular wheel velocity measurement. The proposed method of estimation is verified through a one-wheel simulation model with a ''Magic formula'' tire model. Simulations results show an excellent reconstruction of the tire force. (orig.)

Correlative roentgenography and morphology of the longitudinal epiphyseal bracket

International Nuclear Information System (INIS)

Ogden, J.A.; Light, T.R.; Conlogue, G.J.; Yale Univ., New Haven, CT

1981-01-01

Detailed examination of a complete chondro-osseous specimen from a patient with duplication of the first ray of the foot revealed the involved metatarsal had a trapezoid-shaped, diaphyseal-metaphyseal osseous unit that was longitudinally bracketed along the lateral side by a functioning physis, epiphysis, and secondary (epiphyseal) ossification center. The physis extended as an arc from the medial proximal side toward and along the lateral side and then back to the medial side distally. The medial side of the diaphysis had a normal periosteum. The longitudinal epiphyseal ossification bracket was a composite of initially separate proximal and distal secondary ossification centers that had progressively extended toward each other and finally coalesced along the laterally placed epiphyseal cartilage. We have termed this deformity the 'longitudinal epiphyseal bracket' (LEB). The macroscopic and microscopic anatomy relevant to initial diagnosis and evaluation of sequential roentgenographic changes will be considered. (orig.)

Improved Longitudinal Blow-up and Shaving in the Booster

CERN Document Server

Hancock, S

2013-01-01

The low-intensity proton beam for p-Pb collisions in the LHC did not come back in the Booster at the beginning of 2013 anything like it had been set up at the end of 2012. In particular there were unexplained intensity fluctuations of ±100%. Although the root cause of the drift in performance was never established, its investigation revealed long-standing issues in the longitudinal plane which, when corrected, allowed single-bunch beams to be delivered with unprecedented reproducibility and control of both intensity and longitudinal emittance. The new approach was adopted for the ion run and subsequently for MDs at higher intensities, where it made possible a robust control of intensity at constant 6D phase space volume. Post-LS1, it may even provide a platform upon which to build a more exotic controlled longitudinal blow-up to generate higher intensity bunches with a flattened line density.

Sample size determination for mediation analysis of longitudinal data.

Science.gov (United States)

Pan, Haitao; Liu, Suyu; Miao, Danmin; Yuan, Ying

2018-03-27

Sample size planning for longitudinal data is crucial when designing mediation studies because sufficient statistical power is not only required in grant applications and peer-reviewed publications, but is essential to reliable research results. However, sample size determination is not straightforward for mediation analysis of longitudinal design. To facilitate planning the sample size for longitudinal mediation studies with a multilevel mediation model, this article provides the sample size required to achieve 80% power by simulations under various sizes of the mediation effect, within-subject correlations and numbers of repeated measures. The sample size calculation is based on three commonly used mediation tests: Sobel's method, distribution of product method and the bootstrap method. Among the three methods of testing the mediation effects, Sobel's method required the largest sample size to achieve 80% power. Bootstrapping and the distribution of the product method performed similarly and were more powerful than Sobel's method, as reflected by the relatively smaller sample sizes. For all three methods, the sample size required to achieve 80% power depended on the value of the ICC (i.e., within-subject correlation). A larger value of ICC typically required a larger sample size to achieve 80% power. Simulation results also illustrated the advantage of the longitudinal study design. The sample size tables for most encountered scenarios in practice have also been published for convenient use. Extensive simulations study showed that the distribution of the product method and bootstrapping method have superior performance to the Sobel's method, but the product method was recommended to use in practice in terms of less computation time load compared to the bootstrapping method. A R package has been developed for the product method of sample size determination in mediation longitudinal study design.

Associations of Dairy Intake with Arterial Stiffness in Brazilian Adults: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Science.gov (United States)

Ribeiro, Amanda Gomes; Mill, José Geraldo; Cade, Nágela Valadão; Velasquez-Melendez, Gustavo; Matos, Sheila Maria Alvim; Molina, Maria Del Carmen Bisi

2018-05-31

Recent studies have suggested the possible effect of dairy product intake on cardiovascular risk markers, including arterial stiffness. Our aim was to investigate whether dairy food intake is associated with arterial stiffness, which we assessed by carotid-femoral pulse wave velocity (cfPWV) and pulse pressure (PP) in a cross-sectional analysis of baseline data (2008⁻2010; n = 12,892) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Dairy consumption was evaluated with a validated food-frequency questionnaire (FFQ) by computing servings per day for total and subgroups of dairy products. Dairy consumption was described in four categories (≤1 serving/day to >4 servings/day). Covariance analysis (ANCOVA) was used to compare cfPWV across increasing intake of dairy food, adjusting for confounding factors, including non-dairy food groups. The intake of total dairy was inversely associated with cfPWV and PP (-0.13 m/s and -1.3 mmHg, from the lowest and to the highest category of dairy intake). Low-fat dairy, fermented dairy and cheese showed an inverse relationship with cfPWV and PP. These findings suggest a beneficial effect of dairy consumption to reduce arterial stiffness. However, further evidence from longitudinal studies or long-term intervention is needed to support reduction of cfPWV and PP mediating the beneficial effects of dairy products on cardiovascular health.

Associations of Dairy Intake with Arterial Stiffness in Brazilian Adults: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil

Directory of Open Access Journals (Sweden)

Amanda Gomes Ribeiro

2018-05-01

Full Text Available Recent studies have suggested the possible effect of dairy product intake on cardiovascular risk markers, including arterial stiffness. Our aim was to investigate whether dairy food intake is associated with arterial stiffness, which we assessed by carotid-femoral pulse wave velocity (cfPWV and pulse pressure (PP in a cross-sectional analysis of baseline data (2008–2010; n = 12,892 of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil. Dairy consumption was evaluated with a validated food-frequency questionnaire (FFQ by computing servings per day for total and subgroups of dairy products. Dairy consumption was described in four categories (≤1 serving/day to >4 servings/day. Covariance analysis (ANCOVA was used to compare cfPWV across increasing intake of dairy food, adjusting for confounding factors, including non-dairy food groups. The intake of total dairy was inversely associated with cfPWV and PP (−0.13 m/s and −1.3 mmHg, from the lowest and to the highest category of dairy intake. Low-fat dairy, fermented dairy and cheese showed an inverse relationship with cfPWV and PP. These findings suggest a beneficial effect of dairy consumption to reduce arterial stiffness. However, further evidence from longitudinal studies or long-term intervention is needed to support reduction of cfPWV and PP mediating the beneficial effects of dairy products on cardiovascular health.

Peak bone mass from longitudinal data: implications for the prevalence, pathophysiology, and diagnosis of osteoporosis.

Science.gov (United States)

Berger, Claudie; Goltzman, David; Langsetmo, Lisa; Joseph, Lawrence; Jackson, Stuart; Kreiger, Nancy; Tenenhouse, Alan; Davison, K Shawn; Josse, Robert G; Prior, Jerilynn C; Hanley, David A

2010-09-01

We estimated peak bone mass (PBM) in 615 women and 527 men aged 16 to 40 years using longitudinal data from the Canadian Multicentre Osteoporosis Study (CaMos). Individual rates of change were averaged to find the mean rate of change for each baseline age. The age range for PBM was defined as the period during which bone mineral density (BMD) was stable. PBM was estimated via hierarchical models, weighted according to 2006 Canadian Census data. Lumbar spine PBM (1.046 ± 0.123 g/cm(2)) occurred at ages 33 to 40 years in women and at 19 to 33 years in men (1.066 ± 0.129 g/cm(2)). Total hip PBM (0.981 ± 0.122 g/cm(2)) occurred at ages 16 to 19 years in women and 19 to 21 years in men (1.093 ± 0.169 g/cm(2)). Analysis of Canadian geographic variation revealed that the levels of PBM and of mean BMD in those over age 65 sometimes were discordant, suggesting that PBM and subsequent rates of bone loss may be subject to different genetic and/or environmental influences. Based on our longitudinally estimated PBM values, the estimated Canadian prevalences of osteoporosis (T-score < -2.5) were 12.0% (L(1)-L(4)) and 9.1% (total hip) in women aged 50 years and older and 2.9% (L(1)-L(4)) and 0.9% (total hip) in men aged 50 years and older. These were higher than prevalences using cross-sectional PBM data. In summary, we found that the age at which PBM is achieved varies by sex and skeletal site, and different reference values for PBM lead to different estimates of the prevalence of osteoporosis. Furthermore, lack of concordance of PBM and BMD over age 65 suggests different determinants of PBM and subsequent bone loss. © 2010 American Society for Bone and Mineral Research.

Longitudinal Investigation of Adaptive Functioning following Conformal Irradiation for Pediatric Craniopharyngioma and Low-Grade Glioma

Science.gov (United States)

Netson, Kelli L.; Conklin, Heather M.; Wu, Shengjie; Xiong, Xiaoping; Merchant, Thomas E.

2013-01-01

Purpose Children treated for brain tumors with conformal radiation therapy experience preserved cognitive outcomes. Early evidence suggests that adaptive functions or independent living skills may be spared. This longitudinal investigation prospectively examined intellectual and adaptive functioning during the first 5 years following irradiation for childhood craniopharyngioma and low-grade glioma (LGG). The effect of visual impairment on adaptive outcomes was investigated. Methods and Materials Children with craniopharyngioma (n=62) and LGG (n=77) were treated using conformal or intensity-modulated radiation therapy. The median age was 8.05 years (3.21 years –17.64 years) and 8.09 years (2.20 years–19.27 years), respectively. Serial cognitive evaluations including measures of intelligence quotient (IQ) and the Vineland Adaptive Behavior Scales (VABS) were conducted at pre-irradiation baseline, 6 months after treatment, and annually through 5 years. A total of 588 evaluations were completed during the follow-up period. Results Baseline assessment revealed no deficits in IQ and VABS indices for children with craniopharyngioma, with significant (p craniopharyngioma. Children with LGG performed below population norms (p < .05) at baseline on VABS Communication, Daily Living Indices, and the Adaptive Behavior Composite, with significant (p < .05) longitudinal decline limited to VABS Communication. Older age at irradiation was a protective factor against longitudinal decline. Severe visual impairment did not independently correlate with poorer adaptive outcomes for either tumor group. Conclusions There was relative sparing of post-irradiation functional outcomes over time in this sample. Baseline differences in functional abilities prior to the initiation of irradiation suggested that other factors influence functional outcomes above and beyond the effects of irradiation. PMID:23245284

Heritability of Verbal and Performance Intelligence in a Pediatric Longitudinal Sample

NARCIS (Netherlands)

van Soelen, I.L.C.; Brouwer, R.M.; van Leeuwen, M.; Kahn, R.S.; Hulshoff Pol, H.E.; Boomsma, D.I.

2011-01-01

The longitudinal stability of IQ is well-documented as is its increasing heritability with age. In a longitudinal twin study, we addressed the question to what extent heritability and stability differ for full scale (FSIQ), verbal (VIQ), and performance IQ (PIQ) in childhood (age 9-11 years), and

Longitudinal study of self-regulation, positive parenting, and adjustment problems among physically abused children

Science.gov (United States)

Kim, Jungmeen; Haskett, Mary E.; Longo, Gregory S.; Nice, Rachel

2012-01-01

Objective Research using normative and high-risk samples indicates a significant link between problems with self-regulation and child maladjustment. Nevertheless, little is known about the processes that may modify the link between self-regulation and maladjustment. This longitudinal study examined the joint contributions of child self-regulation and positive parenting behaviors to the development of externalizing and internalizing symptomatology spanning from preschool to 1st grade. Methods Data were collected on a total of 95 physically abused children (58% boys); our longitudinal analyses involved 43 children at Time 1 (preschool), 63 children at Time 2 (kindergarten), and 54 children at Time 3 (1st grade). Children's self-regulation was measured by parent report, and their externalizing and internalizing symptomatology was evaluated by teachers. Parents completed self-report measures of positive parenting. Results Our structural equation modeling analyses revealed positive parenting as a protective factor that attenuated the concurrent association between low self-regulation and externalizing symptomatology among physically abused children. Our findings regarding longitudinal changes in children's externalizing symptomatology supported the differential susceptibility hypothesis: Physically abused children who were at greater risk due to low levels of self-regulation were more susceptible to the beneficial effects of positive parenting, compared to those with high levels of self-regulation. Conclusions Findings suggest that although physical abuse presents formidable challenges that interfere with the development of adaptive self-regulation, positive parenting behaviors may ameliorate the detrimental effects of maladaptive self-regulation on the development of externalizing symptomatology. In addition, the positive and negative effects of caregiving behaviors were more prominent among physically abused children at great risk due to low self-regulation. Practice

The Categorical Stability of Gambling Motives Among Community-Recruited Gamblers: A Longitudinal Assessment.

Science.gov (United States)

McGrath, Daniel S; Konkolÿ Thege, Barna

2018-03-01

Over the past decade, several motivational models have been proposed to explain the role of motives in gambling disorder. In the model captured by the four-factor Gambling Motives Questionnaire Financial (GMQ-F), gamblers are described as being primarily motivated to gamble for 'coping', 'enhancement', 'social', and 'financial' reasons. Although this model has received significant empirical support; to date, research assessing the role of motives in gambling disorder has been primarily cross-sectional in nature. Thus, the extent to which gambling motives remain stable over time has yet to be explored. In the current study, the stability versus fluidity of self-assessed gambling motives was investigated using the Quinte Longitudinal Study, a longitudinal dataset of gambling behaviour collected over 5 years. Gambling motives of 2795 gamblers were examined over all five annual assessments. The total proportion of gamblers who stayed in the same primary motive category across each of the 5 consecutive assessments was 22%, indicating substantial fluidity in category membership. Substantial movement between categories was seen for each GMQ-F group, as well as an additional group of non-classified motives. Logistic regression analyses suggest that greater resistance to gambling fallacies significantly predicted stability between the baseline assessment and a follow-up 1 year later, but gambling severity did not. Potential limitations in the study design and opportunities for future research are discussed.

Longitudinal multigroup invariance analysis of the satisfaction with food-related life scale in university students.

Science.gov (United States)

Schnettler, Berta; Miranda, Horacio; Miranda-Zapata, Edgardo; Salinas-Oñate, Natalia; Grunert, Klaus G; Lobos, Germán; Sepúlveda, José; Orellana, Ligia; Hueche, Clementina; Bonilla, Héctor

2017-06-01

This study examined longitudinal measurement invariance in the Satisfaction with Food-related Life (SWFL) scale using follow-up data from university students. We examined this measure of the SWFL in different groups of students, separated by various characteristics. Through non-probabilistic longitudinal sampling, 114 university students (65.8% female, mean age: 22.5) completed the SWFL questionnaire three times, over intervals of approximately one year. Confirmatory factor analysis was used to examine longitudinal measurement invariance. Two types of analysis were conducted: first, a longitudinal invariance by time, and second, a multigroup longitudinal invariance by sex, age, socio-economic status and place of residence during the study period. Results showed that the 3-item version of the SWFL exhibited strong longitudinal invariance (equal factor loadings and equal indicator intercepts). Longitudinal multigroup invariance analysis also showed that the 3-item version of the SWFL displays strong invariance by socio-economic status and place of residence during the study period over time. Nevertheless, it was only possible to demonstrate equivalence of the longitudinal factor structure among students of both sexes, and among those older and younger than 22 years. Generally, these findings suggest that the SWFL scale has satisfactory psychometric properties for longitudinal measurement invariance in university students with similar characteristics as the students that participated in this research. It is also possible to suggest that satisfaction with food-related life is associated with sex and age. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ureter smooth muscle cell orientation in rat is predominantly longitudinal.

Directory of Open Access Journals (Sweden)

Bart Spronck

Full Text Available In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in our approach is to use two-photon laser scanning microscopy and image analysis providing objective, quantitative data on smooth muscle cell orientation in intact ureters, avoiding the usual sectioning artifacts. In 36 rat ureter segments, originating from a proximal, middle or distal site and from a left or right ureter, we found close to the adventitia a well-defined longitudinal smooth muscle orientation. Towards the lamina propria, the orientation gradually became slightly more disperse, yet the main orientation remained longitudinal. We conclude that smooth muscle cell orientation in rat ureter is predominantly longitudinal, though the orientation gradually becomes more disperse towards the proprial side. These findings do not support identification of separate layers. The observed longitudinal orientation suggests that smooth muscle contraction would rather cause local shortening of the ureter, than cause luminal constriction. However, the net-like connective tissue of the ureter wall may translate local longitudinal shortening into co-local luminal constriction, facilitating peristalsis. Our quantitative, minimally invasive approach is a crucial step towards more mechanistic insight into ureter peristalsis, and may also be used to study smooth muscle cell orientation in other tube-like structures like gut and blood vessels.

Ureter smooth muscle cell orientation in rat is predominantly longitudinal.

Science.gov (United States)

Spronck, Bart; Merken, Jort J; Reesink, Koen D; Kroon, Wilco; Delhaas, Tammo

2014-01-01

In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in our approach is to use two-photon laser scanning microscopy and image analysis providing objective, quantitative data on smooth muscle cell orientation in intact ureters, avoiding the usual sectioning artifacts. In 36 rat ureter segments, originating from a proximal, middle or distal site and from a left or right ureter, we found close to the adventitia a well-defined longitudinal smooth muscle orientation. Towards the lamina propria, the orientation gradually became slightly more disperse, yet the main orientation remained longitudinal. We conclude that smooth muscle cell orientation in rat ureter is predominantly longitudinal, though the orientation gradually becomes more disperse towards the proprial side. These findings do not support identification of separate layers. The observed longitudinal orientation suggests that smooth muscle contraction would rather cause local shortening of the ureter, than cause luminal constriction. However, the net-like connective tissue of the ureter wall may translate local longitudinal shortening into co-local luminal constriction, facilitating peristalsis. Our quantitative, minimally invasive approach is a crucial step towards more mechanistic insight into ureter peristalsis, and may also be used to study smooth muscle cell orientation in other tube-like structures like gut and blood vessels.

Cohort Profile: Footprints in Time, the Australian Longitudinal Study of Indigenous Children.

Science.gov (United States)

Thurber, Katherine A; Banks, Emily; Banwell, Cathy

2015-06-01

Indigenous Australians experience profound levels of disadvantage in health, living standards, life expectancy, education and employment, particularly in comparison with non-Indigenous Australians. Very little information is available about the healthy development of Australian Indigenous children; the Longitudinal Study of Indigenous Children (LSIC) is designed to fill this knowledge gap.This dataset provides an opportunity to follow the development of up to 1759 Indigenous children. LSIC conducts annual face-to-face interviews with children (aged 0.5-2 and 3.5-5 years at baseline in 2008) and their caregivers. This represents between 5% and 10% of the total population of Indigenous children in these age groups, including families of varied socioeconomic and cultural backgrounds. Study topics include: the physical, social and emotional well-being of children and their caregivers; language; culture; parenting; and early childhood education.LSIC is a shared resource, formed in partnership with communities; its data are readily accessible through the Australian Government Department of Social Services (see http://dss.gov.au/lsic for data and access arrangements). As one of very few longitudinal studies of Indigenous children, and the only national one, LSIC will enable an understanding of Indigenous children from a wide range of environments and cultures. Findings from LSIC form part of a growing infrastructure from which to understand Indigenous child health. © The Author 2014. Published by Oxford University Press on behalf of the International Epidemiological Association.

Making meaning in the time of AIDS: longitudinal narratives from the ...

African Journals Online (AJOL)

Second, beyond what can be learned from the journals about individual and collective responses to AIDS, they suggest the value of longitudinal observational field studies as a method for understanding how cultural change occurs. And third, as an example of the potential of longitudinal field studies as a research method ...

A Longitudinal Study of Lexical Development in Children Learning Vietnamese and English

Science.gov (United States)

Pham, Giang; Kohnert, Kathryn

2013-01-01

This longitudinal study modeled lexical development among children who spoke Vietnamese as a first language (L1) and English as a second language (L2). Participants (n=33, initial mean age of 7.3 years) completed a total of eight tasks (four in each language) that measured vocabulary knowledge and lexical processing at four yearly time points. Multivariate hierarchical linear modeling was used to calculate L1 and L2 trajectories within the same model for each task. Main findings included (a) positive growth in each language, (b) greater gains in English resulting in shifts toward L2 dominance, and (c) different patterns for receptive and expressive domains. Timing of shifts to L2 dominance underscored L1 skills that are resilient and vulnerable to increases in L2 proficiency. PMID:23869741

An alternative longitudinal polarization scheme for tristan

International Nuclear Information System (INIS)

Chao, A.W.; Yokoya, Kaoru.

1981-07-01

For electron storage rings general conditions are derived to get a high level longitudinal polarization and a possible design of the experimental insertion for TRISTAN e-p collider is presented. (author)

Crecimiento longitudinal posnatal del primer metatarsiano. [Longitudinal postnatal growth of the first metatarsal bone

Directory of Open Access Journals (Sweden)

Julio J. Masquijo

2014-10-01

Full Text Available Introducción: si bien el crecimiento prenatal y posnatal del pie ha sido documentado hace varios años, el crecimiento longitudinal del primer metatarsiano en particular no ha sido estudiado previamente. El objetivo del estudio es determinar el patrón de crecimiento longitudinal posnatal de este hueso y compararlo con el del pie y los huesos largos del miembro inferior. Materiales y Métodos: mediante una búsqueda informatizada, se identificaron pacientes <18 años de edad con radiografías informadas como “normal” por el radiólogo. Se analizó una muestra de 886 pacientes divididos en 18 grupos según la edad (0-11 meses, 1 año, 2 años, etc. y el sexo. El análisis de las imágenes se realizó con un software de imágenes Kodak Carestream PACS. Resultados: el largo promedio en el primer grupo fue de 19,91 mm (3,20; 15,22-25,62. El largo promedio en el último grupo fue de 66,13 mm (5,33; 52,50-77,18. La tasa de crecimiento anual fue de 2,71 mm. La edad promedio al momento del cierre de la fisis fue de 14.85 años (± 1.64 para los varones y 14.77 años (± 3.63 para las niñas. Conclusión: el crecimiento del primer metatarsiano acompaña el crecimiento longitudinal del pie, pero no el de los huesos largos del miembro inferior. Las curvas de crecimiento del primer metatarsiano descritas en este artículo pueden ser aplicadas en patologías que afectan el desarrollo del pie o que requieren cirugía de corrección sobre el primer metatarsiano, o se las puede emplear como estándar de referencia en futuros estudios.

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

Science.gov (United States)

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

2017-09-20

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

Longitudinal tracking studies for a high intensity proton synchrotron

International Nuclear Information System (INIS)

Lessner, E.; Cho, Y.; Harkay, K.; Symon, K.

1995-01-01

Results from longitudinal tracking studies for a high intensity proton synchrotron designed for a 1-MW spallation source are presented. The machine delivers a proton beam of 0.5 mA time-averaged current at a repetition rate of 30 Hz. The accelerator is designed to have radiation levels that allow hands-on-maintenance. However, the high beam intensity causes strong space charge fields whose effects may lead to particle loss and longitudinal instabilities. The space charge fields modify the particle distribution, distort the stable bucket area and reduce the rf linear restoring force. Tracking simulations were conducted to analyze the space charge effects on the dynamics of the injection and acceleration processes and means to circumvent them. The tracking studies led to the establishment of the injected beam parameters and rf voltage program that minimized beam loss and longitudinal instabilities. Similar studies for a 10-GeV synchrotron that uses the 2-GeV synchrotron as its injector are also discussed

Longitudinal intensity effects in the CERN Large Hadron Collider

CERN Document Server

AUTHOR|(CDS)2081238; Rivkin, Leonid

This PhD thesis provides an improved knowledge of the LHC longitudinal impedance model and a better understanding of the longitudinal intensity effects. These effects can limit the LHC performance and lead to a reduction of the integrated luminosity. The LHC longitudinal impedance was measured with beams. Results obtained using traditional techniques are consistent with the expectations based on the impedance model, although the measurement precision was proven insufficient for the low impedance of the LHC. Innovative methods to probe the LHC reactive impedance were successfully used. One of the methods is based on exciting the beam with a sinusoidal rf phase modulation to estimate the synchrotron frequency shift from potential-well distortion. In the second method, the impedance is estimated from the loss of Landau damping threshold, which is also found to be in good agreement with analytical estimations. Beam-based impedance measurements agree well with estimations using the LHC impedance model. Macropartic...

Peer substance use as a mediator between early pubertal timing and adolescent substance use: longitudinal associations and moderating effect of maltreatment.

Science.gov (United States)

Negriff, Sonya; Trickett, Penelope K

2012-11-01

Early pubertal timing has received considerable empirical support as a risk for adolescent substance use. However, few studies have examined the mediators linking these variables. Therefore, the aims of this study were (1) to examine peer substance use as a mediator between pubertal timing and adolescent substance use longitudinally and (2) to test gender and maltreatment experience as moderators of the mediational model. Data were obtained from time 1, 2, and 3 of a longitudinal study of maltreatment and development. At time 1 the sample was comprised of 303 maltreated and 151 comparison children aged 9-13 years (213 females and 241 males). Longitudinal mediation was tested using structural equation modeling and moderating effects were tested using multiple group analysis. Peer substance use mediated the relationship between early pubertal timing and later adolescent substance use for the total sample. Moderation analyses indicated this significant indirect effect did not differ for males and females. However, it did differ for maltreated versus comparison adolescents with the mediational effect only remaining significant for the comparison group. This is one of the first studies to examine peer substance use as a mediator of pubertal timing and adolescent substance use using a longitudinal design. Early maturing males are at equal risk to early maturing females for interacting with peers that may draw them into substance use. Additionally, the findings indicate that while peers are mediators for comparison adolescents a different mechanism may link early puberty to substance use for maltreated adolescents. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stability of longitudinal bunch length feedback for heavy-ion synchrotrons

Directory of Open Access Journals (Sweden)

D. Lens

2013-03-01

Full Text Available In heavy-ion synchrotrons such as the SIS18 at Helmholtzzentrum für Schwerionenforschung, Helmholtz Centre for Heavy Ion Research (GSI, coherent oscillations of the particle bunches are damped by rf feedback systems to increase the stability and to improve the beam quality. In the longitudinal direction, important modes are the coherent longitudinal dipole and quadrupole oscillation. In this paper we present a new and rigorous approach to analyze the longitudinal feedback to damp these modes. The results are applied to the rf feedback loop at GSI that damps the quadrupole mode. The stability analysis is compared with simulations and is in good agreement with results of a beam experiment. Finally, we summarize practical implications for the operation of the feedback system regarding performance and stability.

Statistical Power in Longitudinal Network Studies

NARCIS (Netherlands)

Stadtfeld, Christoph; Snijders, Tom A. B.; Steglich, Christian; van Duijn, Marijtje

2018-01-01

Longitudinal social network studies may easily suffer from a lack of statistical power. This is the case in particular for studies that simultaneously investigate change of network ties and change of nodal attributes. Such selection and influence studies have become increasingly popular due to the

Intelligent control for braking-induced longitudinal vibration responses of floating-type railway bridges

Science.gov (United States)

Qu, Wei-Lian; Qin, Shun-Quan; Tu, Jian-Weia; Liu, Jia; Zhou, Qiang; Cheng, Haibin; Pi, Yong-Lin

2009-12-01

This paper presents an intelligent control method and its engineering application in the control of braking-induced longitudinal vibration of floating-type railway bridges. Equations of motion for the controlled floating-type railway bridges have been established based on the analysis of the longitudinal vibration responses of floating-type railway bridges to train braking and axle-loads of moving trains. For engineering applications of the developed theory, a full-scale 500 kN smart magnetorheologic (MR) damper has been designed, fabricated and used to carry out experiments on the intelligent control of braking-induced longitudinal vibration. The procedure for using the developed intelligent method in conjunction with the full-scale 500 kN MR dampers has been proposed and used to control the longitudinal vibration responses of the deck of floating-type railway bridges induced by train braking and axle-loads of moving trains. This procedure has been applied to the longitudinal vibration control of the Tian Xingzhou highway and railway cable-stayed bridge over the Yangtze River in China. The simulated results have shown that the intelligent control system using the smart MR dampers can effectively control the longitudinal response of the floating-type railway bridge under excitations of braking and axle-loads of moving trains.

Intelligent control for braking-induced longitudinal vibration responses of floating-type railway bridges

International Nuclear Information System (INIS)

Qu, Wei-Lian; Tu, Jian-Weia; Liu, Jia; Zhou, Qiang; Qin, Shun-Quan; Cheng, Haibin; Pi, Yong-Lin

2009-01-01

This paper presents an intelligent control method and its engineering application in the control of braking-induced longitudinal vibration of floating-type railway bridges. Equations of motion for the controlled floating-type railway bridges have been established based on the analysis of the longitudinal vibration responses of floating-type railway bridges to train braking and axle-loads of moving trains. For engineering applications of the developed theory, a full-scale 500 kN smart magnetorheologic (MR) damper has been designed, fabricated and used to carry out experiments on the intelligent control of braking-induced longitudinal vibration. The procedure for using the developed intelligent method in conjunction with the full-scale 500 kN MR dampers has been proposed and used to control the longitudinal vibration responses of the deck of floating-type railway bridges induced by train braking and axle-loads of moving trains. This procedure has been applied to the longitudinal vibration control of the Tian Xingzhou highway and railway cable-stayed bridge over the Yangtze River in China. The simulated results have shown that the intelligent control system using the smart MR dampers can effectively control the longitudinal response of the floating-type railway bridge under excitations of braking and axle-loads of moving trains

Physical Activity and Personality Development over Twenty Years: Evidence from Three Longitudinal Samples.

Science.gov (United States)

Stephan, Yannick; Sutin, Angelina R; Luchetti, Martina; Bosselut, Grégoire; Terracciano, Antonio

2018-04-01

A physically inactive lifestyle is associated with maladaptive patterns of personality development over relatively short follow-up periods. The present study extends existing research by examining whether this association persists over 20 years. Participants (total N = 8,723) were drawn from the Wisconsin Longitudinal Study Graduates and Siblings samples and the Midlife in the United States Study. Controlling for demographic factors and disease burden, baseline physical inactivity was related to steeper declines in conscientiousness in all three samples and a meta-analysis (β=-.06). The meta-analysis further showed that lower physical activity was associated with declines in openness (β=-.05), extraversion (β=-.03), and agreeableness (β=-.03). These findings provide evidence that a physically inactive lifestyle is associated with long-term detrimental personality trajectories.

Racism, ethnic density and psychological well-being through adolescence: evidence from the Determinants of Adolescent Social well-being and Health longitudinal study

OpenAIRE

Astell-Burt, Thomas; Maynard, Maria J.; Lenguerrand, Erik; Harding, Seeromanie

2012-01-01

Objective. To investigate the effect of racism, own-group ethnic density, diversity and deprivation on adolescent trajectories in psychological well-being. Design. Multilevel models were used in longitudinal analysis of psychological well-being (total difficulties score (TDS) from Goodman's Strengths and Difficulties Questionnaire, higher scores correspond to greater difficulties) for 4782 adolescents aged 11–16 years in 51 London (UK) schools. Individual level variables included ethnicity, r...

Longitudinal Losses Due to Breathing Mode Excitation in Radiofrequency Linear Accelerators

OpenAIRE

Channell, Paul J.

2010-01-01

Transverse breathing mode oscillations in a particle beam can couple energy into longitudinal oscillations in a bunch of finite length and cause significant losses. We develop a model that illustrates this effect and explore the dependence on mismatch size, space-charge tune depression, longitudinal focusing strength, bunch length, and RF bucket length.

Substance use and motivation: a longitudinal perspective.

Science.gov (United States)

Korcha, Rachael A; Polcin, Douglas L; Bond, Jason C; Lapp, William M; Galloway, Gantt

2011-01-01

Motivation to change substance use behavior is an important component of the recovery process that has usually been studied at entry into treatment. Less studied, but equally important, is the measurement of motivation over time and the role motivation plays in subsequent substance use. The present study sought to examine longitudinal motivation toward sobriety among residents of sober living houses. Sober living residents (n = 167) were followed at 6-month intervals over an 18-month period and assessed for motivation and substance use outcomes at each study interview. Motivation was measured using the costs and benefits subscales of the Alcohol and Drug Consequences Questionnaire (ADCQ) and substance use outcomes included the Addiction Severity Index (ASI) alcohol scale, ASI drug scale, and peak density of substance use (number of days of most use in a month). Participants reported higher benefits than costs of sobriety or cutting down substance use at every study time point. Using lagged generalized estimating equation models, the ADCQ costs predicted increased severity for alcohol, drugs, and peak density, whereas the benefits subscale predicted decreased drug and peak density. Longitudinal measurement of motivation can be a useful clinical tool to understand later substance use problems. Given the mixed findings from prior studies on the effects of baseline motivation, a shift toward examining longitudinal measures of motivation at proximal and temporal intervals is indicated.

Sensitivity analysis of longitudinal cracking on asphalt pavement using MEPDG in permafrost region

Directory of Open Access Journals (Sweden)

Chen Zhang

2015-02-01

Full Text Available Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every parameter on longitudinal cracking, which can help optimizing the design of the pavement structure. In this study, 20 test sections of Qinghai–Tibet Highway were selected to conduct the sensitivity analysis of longitudinal cracking on material parameter based on Mechanistic-Empirical Pavement Design Guide (MEPDG and single factorial sensitivity analysis method. Some computer aided engineering (CAE simulation techniques, such as the Latin hypercube sampling (LHS technique and the multiple regression analysis are used as auxiliary means. Finally, the sensitivity spectrum of material parameter on longitudinal cracking was established. The result shows the multiple regression analysis can be used to determine the remarkable influence factor more efficiently and to process the qualitative analysis when applying the MEPDG software in sensitivity analysis of longitudinal cracking in permafrost regions. The effect weights of the three parameters on longitudinal cracking in descending order are air void, effective binder content and PG grade. The influence of air void on top layer is bigger than that on middle layer and bottom layer. The influence of effective asphalt content on top layer is bigger than that on middle layer and bottom layer, and the influence of bottom layer is slightly bigger than middle layer. The accumulated value of longitudinal cracking on middle layer and bottom layer in the design life would begin to increase when the design temperature of PG grade increased.

Longitudinal study of urban malaria in a cohort of Ugandan children: description of study site, census and recruitment

Directory of Open Access Journals (Sweden)

Staedke Sarah G

2006-03-01

Full Text Available Abstract Background Studies of malaria in well-defined cohorts offer important data about the epidemiology of this complex disease, but few have been done in urban African populations. To generate a sampling frame for a longitudinal study of malaria incidence and treatment in Kampala, Uganda, a census, mapping and survey project was conducted. Methods All households in a geographically defined area were enumerated and mapped. Probability sampling was used to recruit a representative sample of children and collect baseline descriptive data for future longitudinal studies. Results 16,172 residents living in 4931 households in a densely-populated community (18,824 persons/km2 were enumerated. A total of 582 households were approached with at least one child less than 10 years of age in order to recruit 601 children living in 322 households. At enrollment, 19% were parasitaemic, 24% were anaemic, 43% used bednets, and 6% used insecticide-treated nets. Low G6PD activity (OR = 0.33, P = 0.009 and bednet use (OR = 0.64, P = 0.045 were associated with a decreased risk of parasitaemia. Increasing age (OR = 0.62 for each year, P Conclusion Detailed surveys of target populations in urban Africa can provide valuable descriptive data and provide a sampling frame for recruitment of representative cohorts for longitudinal studies. Plans to use a multi-disciplinary approach to improve the understanding of the distribution and determinants of malaria incidence and response to therapy in this population are discussed.

Chiral current generation in QED by longitudinal photons

Energy Technology Data Exchange (ETDEWEB)

Acosta Avalo, J.L., E-mail: jlacosta@instec.cu [Instituto Superior de Tecnologías y Ciencias Aplicadas (INSTEC), Ave Salvador Allende, No. 1110, Vedado, La Habana 10400 (Cuba); Pérez Rojas, H., E-mail: hugo@icimaf.cu [Instituto de Cibernética, Matemática y Física (ICIMAF), Calle E esq 15, No. 309, Vedado, La Habana 10400 (Cuba)

2016-08-15

We report the generation of a pseudovector electric current having imbalanced chirality in an electron–positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler–Bell–Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone) contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone). In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

Chiral current generation in QED by longitudinal photons

Directory of Open Access Journals (Sweden)

J.L. Acosta Avalo

2016-08-01

Full Text Available We report the generation of a pseudovector electric current having imbalanced chirality in an electron–positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler–Bell–Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone. In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

Matrix solution to longitudinal impedance of multi-layer circular structures

Energy Technology Data Exchange (ETDEWEB)

Hahn,H.

2008-10-01

A matrix method in which radial wave propagation is treated in analogy to longitudinal transmission lines is presented and applied to finding the longitudinal coupling impedance of axially symmetric multi-layer beam tubes. The method is demonstrated in the case of a Higher Order Mode ferrite absorber with an inserted coated ceramic beam tube. The screening of the ferrite damping properties by the dielectric beam tube is discussed.

A Longitudinal Study on Human Outdoor Decomposition in Central Texas.

Science.gov (United States)

Suckling, Joanna K; Spradley, M Katherine; Godde, Kanya

2016-01-01

The development of a methodology that estimates the postmortem interval (PMI) from stages of decomposition is a goal for which forensic practitioners strive. A proposed equation (Megyesi et al. 2005) that utilizes total body score (TBS) and accumulated degree days (ADD) was tested using longitudinal data collected from human remains donated to the Forensic Anthropology Research Facility (FARF) at Texas State University-San Marcos. Exact binomial tests examined the rate of the equation to successfully predict ADD. Statistically significant differences were found between ADD estimated by the equation and the observed value for decomposition stage. Differences remained significant after carnivore scavenged donations were removed from analysis. Low success rates for the equation to predict ADD from TBS and the wide standard errors demonstrate the need to re-evaluate the use of this equation and methodology for PMI estimation in different environments; rather, multivariate methods and equations should be derived that are environmentally specific. © 2015 American Academy of Forensic Sciences.

Self-consistent calculation of the longitudinal NMR for the Balian--Werthamer and Anderson--Brinkman--Morel states of superfluid 3He

International Nuclear Information System (INIS)

Tewordt, L.; Fay, D.; Doerre, P.; Einzel, D.

1975-01-01

The general equations of motion for the Green's functions and correlation functions and the associated conservation laws for an anisotropic superfluid are derived. This leads to a simple commutator relation for the total angular momentum of the system and the p-wave pair amplitude. The longitudinal NMR frequencies for both the Balian--Werthamer (BW) and Anderson--Brinkman--Morel (ABM) states are calculated rigorously within the self-consistent random phase approximation scheme, taking account of all the degrees of freedom of the complex fluctuations of the order parameter (18 components) and their couplings via the dipole interactions. The results for the low-frequency resonances (ω much less than Δ) are in agreement with those of Leggett except in the vicinity of T/sub c/. In addition, in the presence of the dipole interaction, we find longitudinal resonances at ω = (8/5)/sup 1/2/Δ and ω = 2/sup 1/2/Δ for the BW and ABM states, respectively. (2 figures)

Religious Participation is Associated with Increases in Religious Social Support in a National Longitudinal Study of African Americans.

Science.gov (United States)

Le, Daisy; Holt, Cheryl L; Hosack, Dominic P; Huang, Jin; Clark, Eddie M

2016-08-01

This study reports on the association between religious beliefs and behaviors and the change in both general and religious social support using two waves of data from a national sample of African Americans. The Religion and Health in African Americans (RHIAA) study is a longitudinal telephone survey designed to examine relationships between various aspects of religious involvement and psychosocial factors over time. RHIAA participants were 3173 African American men (1281) and women (1892). A total of 1251 men (456) and women (795) participated in wave 2 of data collection. Baseline religious behaviors were associated with increased overall religious social support from baseline to wave 2 (p social support from baseline to wave 2 in each of the following religious social support subscales: emotional support received (p social support. African Americans who are active in faith communities showed increases in all types of religious social support, even the negative aspects, over a relatively modest longitudinal study period. This illustrates the strength of the church as a social network and the role that it plays in people's lives.

Adverse effects of effort-reward imbalance on work ability: longitudinal findings from the German Sociomedical Panel of Employees.

Science.gov (United States)

Bethge, Matthias; Radoschewski, Friedrich Michael

2012-10-01

The aim of this paper was to analyse the longitudinal effects of effort-reward imbalance (ERI) on work ability, mental health and physical functioning. A total of 603 men and women aged 30-59 years participating in the first two waves of the German Sociomedical Panel of Employees were included in the analyses. Work ability was assessed using the Work Ability Index. Mental health and physical functioning were assessed using scales of the Medical Outcomes Study 36-item Short-Form Health Survey. Our longitudinal analysis showed that high ERI-related work stress exposure at baseline was associated with a decrease in work ability, mental health and physical functioning over time. In case of work ability (b=-0.512; 95% CI -1.018 to -0.006) and mental health (b=-2.026; 95% CI -3.483 to -0.568), this also held true after adjusting for other factors of the work environment (physical demands, job control and psychological job demands). Work stress by ERI has an impact on work ability independent of and above that of other known explanatory variables.

A Longitudinal Study of Usability in Health Care

DEFF Research Database (Denmark)

Kjeldskov, Jesper; Skov, Mikael B.; Stage, Jan

2010-01-01

We report from a longitudinal laboratory-based usability evaluation of a health care information system. The purpose of the study was to inquire into the nature of usability problems experienced by novice and expert users, and to see to what extend usability problems of a health care information...... system may or may not disappear over time, as the nurses get more familiar with it-if time heals poor design? As our method for studying this, we conducted a longitudinal study with two key studies. A usability evaluation was conducted with novice users when an electronic patient record system was being......, we discuss implications for evaluating usability in health care....

Stressful life events as predictors of functioning: findings from the Collaborative Longitudinal Personality Disorders Study

Science.gov (United States)

Pagano, M. E.; Skodol, A. E.; Stout, R. L.; Shea, M. T.; Yen, S.; Grilo, C. M.; Sanislow, C. A.; Bender, D. S.; McGlashan, T. H.; Zanarini, M. C.; Gunderson, J. G.

2008-01-01

Objective Although much attention has been given to the effects of adverse childhood experiences on the development of personality disorders (PDs), we know far less about how recent life events influence the ongoing course of functioning. We examined the extent to which PD subjects differ in rates of life events and the extent to which life events impact psychosocial functioning. Method A total of 633 subjects were drawn from the Collaborative Longitudinal Personality Disorders Study (CLPS), a multi-site study of four personality disorders – schizotypal (STPD), borderline (BPD), avoidant (AVPD), obsessive-compulsive (OCPD) – and a comparison group of major depressive disorders (MDD) without PD. Results Borderline personality disorder subjects reported significantly more total negative life events than other PDs or subjects with MDD. Negative events, especially interpersonal events, predicted decreased psychosocial functioning over time. Conclusion Our findings indicate higher rates of negative events in subjects with more severe PDs and suggest that negative life events adversely impact multiple areas of psychosocial functioning. PMID:15521826

Longitudinal density monitor for the LHC

Science.gov (United States)

Jeff, A.; Andersen, M.; Boccardi, A.; Bozyigit, S.; Bravin, E.; Lefevre, T.; Rabiller, A.; Roncarolo, F.; Welsch, C. P.; Fisher, A. S.

2012-03-01

The longitudinal density monitor (LDM) is primarily intended for the measurement of the particle population in nominally empty rf buckets. These so-called satellite or ghost bunches can cause problems for machine protection as well as influencing the luminosity calibration of the LHC. The high dynamic range of the system allows measurement of ghost bunches with as little as 0.01% of the main bunch population at the same time as characterization of the main bunches. The LDM is a single-photon counting system using visible synchrotron light. The photon detector is a silicon avalanche photodiode operated in Geiger mode, which allows the longitudinal distribution of the LHC beams to be measured with a resolution of 90 ps. Results from the LDM are presented, including a proposed method for constructing a 3-dimensional beam density map by scanning the LDM sensor in the transverse plane. In addition, we present a scheme to improve the sensitivity of the system by using an optical switching technique.

Longitudinal patterns of gambling activities and associated risk factors in college students

NARCIS (Netherlands)

Goudriaan, Anna E.; Slutske, Wendy S.; Krull, Jennifer L.; Sher, Kenneth J.

2009-01-01

To investigate which clusters of gambling activities exist within a longitudinal study of college health, how membership in gambling clusters change over time and whether particular clusters of gambling are associated with unhealthy risk behaviour. Four-year longitudinal study (2002-2006). Large,

Theory and simulations of radiation friction induced enhancement of laser-driven longitudinal fields

Science.gov (United States)

Gelfer, E. G.; Fedotov, A. M.; Weber, S.

2018-06-01

We consider the generation of a quasistatic longitudinal electric field by intense laser pulses propagating in a transparent plasma with radiation friction (RF) taken into account. For both circular and linear polarization of the driving pulse we develop a 1D analytical model of the process, which is valid in a wide range of laser and plasma parameters. We define the parameter region where RF results in an essential enhancement of the longitudinal field. The amplitude and the period of the generated longitudinal wave are estimated and optimized. Our theoretical predictions are confirmed by 1D and 2D PIC simulations. We also demonstrate numerically that RF should substantially enhance the longitudinal field generated in a plasma by a 10 PW laser such as ELI Beamlines.

Longitudinal outcomes after tibioperoneal angioplasty alone compared to tibial stenting and atherectomy for critical limb ischemia.

Science.gov (United States)

Reynolds, Shaun; Galiñanes, Edgar Luis; Dombrovskiy, Viktor Y; Vogel, Todd R

2013-10-01

There are limited data available evaluating longitudinal outcomes after tibioperoneal angioplasty (TA) alone compared to adjunctive tibial procedures including stenting and atherectomy. Using the Centers for Medicare & Medicaid Services inpatient claims (2005-2007), patients evaluated TA only, TA plus stent placement (TA + S), and TA plus atherectomy (TA + A). A total of 2080 patients with critical limb ischemia underwent percutaneous tibioperoneal intervention for the indication of ulceration. Procedures included TA (56.3%), TA + S (16.2%), and TA + A (27.5%). Rates of amputation were not statistically different between the groups at 30, 90, and 365 days after the intervention. Mean total hospital charges were TA ($35,867), TA + A ($41,698; P = .0004), and TA + S ($51,040; P atherectomy for ulceration demonstrated no improvement in limb salvage. Future analysis of adjunctive tibioperoneal interventions is essential to temper cost, as they fail to improve long-term limb salvage.

Longitudinal Variation of the Lunar Tide in the Equatorial Electrojet

Science.gov (United States)

Yamazaki, Yosuke; Stolle, Claudia; Matzka, Jürgen; Siddiqui, Tarique A.; Lühr, Hermann; Alken, Patrick

2017-12-01

The atmospheric lunar tide is one known source of ionospheric variability. The subject received renewed attention as recent studies found a link between stratospheric sudden warmings and amplified lunar tidal perturbations in the equatorial ionosphere. There is increasing evidence from ground observations that the lunar tidal influence on the ionosphere depends on longitude. We use magnetic field measurements from the CHAMP satellite during July 2000 to September 2010 and from the two Swarm satellites during November 2013 to February 2017 to determine, for the first time, the complete seasonal-longitudinal climatology of the semidiurnal lunar tidal variation in the equatorial electrojet intensity. Significant longitudinal variability is found in the amplitude of the lunar tidal variation, while the longitudinal variability in the phase is small. The amplitude peaks in the Peruvian sector (˜285°E) during the Northern Hemisphere winter and equinoxes, and in the Brazilian sector (˜325°E) during the Northern Hemisphere summer. There are also local amplitude maxima at ˜55°E and ˜120°E. The longitudinal variation is partly due to the modulation of ionospheric conductivities by the inhomogeneous geomagnetic field. Another possible cause of the longitudinal variability is neutral wind forcing by nonmigrating lunar tides. A tidal spectrum analysis of the semidiurnal lunar tidal variation in the equatorial electrojet reveals the dominance of the westward propagating mode with zonal wave number 2 (SW2), with secondary contributions by westward propagating modes with zonal wave numbers 3 (SW3) and 4 (SW4). Eastward propagating waves are largely absent from the tidal spectrum. Further study will be required for the relative importance of ionospheric conductivities and nonmigrating lunar tides.

Generation of ten kilotesla longitudinal magnetic fields in ultraintense laser-solenoid target interactions

OpenAIRE

Xiao, K. D.; Zhou, C. T.; Zhang, H.; Huang, T. W.; Li, R.; Qiao, B.; Cao, J. M.; Cai, T. X.; Ruan, S. C.; He, X. T.

2018-01-01

Production of the huge longitudinal magnetic fields by using an ultraintense laser pulse irradiating a solenoid target is considered. Through three-dimensional particle-in-cell simulations, it is shown that the longitudinal magnetic field up to ten kilotesla can be observed in the ultraintense laser-solenoid target interactions. The finding is associated with both fast and return electron currents in the solenoid target. The huge longitudinal magnetic field is of interest for a number of impo...

Fundamentals - longitudinal motion

International Nuclear Information System (INIS)

Weng, W.T.

1989-01-01

There are many ways to accelerate charged particles to high energy for physics research. Each has served its purpose but eventually has encountered fundamental limitations of one kind or another. Looking at the famous Livingston curve, the initial birth and final level-off of all types of accelerators is seen. In fact, in the mid-80s we personally witnessed the creation of a new type of collider - the Stanford Linear Collider. Also witnessed, was the resurgence of study into novel methods of acceleration. This paper will cover acceleration and longitudinal motion in a synchrotron. A synchrotron is a circular accelerator with the following three characteristics: (1) Magnetic guiding (dipole) and confinement (quadrupole) components are placed in a small neighborhood around the equilibrium orbit. (2) Particles are kept in resonance with the radio-frequency electric field indefinitely to achieve acceleration to higher energies. (3) Magnetic fields are varied adiabatically with the energy of the particle. D. Edwards described the transverse oscillations of particles in a synchrotron. Here the author talks about the longitudinal oscillations of particles. The phase stability principle was invented by V. Veksler and E. McMillan independently in 1945. The phase stability and strong focusing principle, invented by Courant and Livingston in 1952, enabled the steady energy gain of accelerators and storage rings witnessed during the past 30 years. This paper is a unified overview of the related rf subjects in an accelerator and a close coupling between accelerator physics and engineering practices, which is essential for the major progress in areas such as high intensity synchrotrons, a multistage accelerator complex, and anti-proton production and cooling, made possible in the past 20 years

Dynamics of Longitudinal Impact in the Variable Cross-Section Rods

Science.gov (United States)

Stepanov, R.; Romenskyi, D.; Tsarenko, S.

2018-03-01

Dynamics of longitudinal impact in rods of variable cross-section is considered. Rods of various configurations are used as elements of power pulse systems. There is no single method to the construction of a mathematical model of longitudinal impact on rods. The creation of a general method for constructing a mathematical model of longitudinal impact for rods of variable cross-section is the goal of the article. An elastic rod is considered with a cross-sectional area varying in powers of law from the longitudinal coordinate. The solution of the wave equation is obtained using the Fourier method. Special functions are introduced on the basis of recurrence relations for Bessel functions for solving boundary value problems. The expression for the square of the norm is obtained taking into account the orthogonality property of the eigen functions with weight. For example, the impact of an inelastic mass along the wide end of a conical rod is considered. The expressions for the displacements, forces and stresses of the rod sections are obtained for the cases of sudden velocity communication and the application of force. The proposed mathematical model makes it possible to carry out investigations of the stress-strain state in rods of variable and constant cross-section for various conditions of dynamic effects.

High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

Directory of Open Access Journals (Sweden)

Mihai Valentin Predoi

2014-01-01

Full Text Available Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.

A longitudinal study of human milk composition in the second year postpartum: implications for human milk banking.

Science.gov (United States)

Perrin, Maryanne T; Fogleman, April D; Newburg, David S; Allen, Jonathan C

2017-01-01

While the composition of human milk has been studied extensively in the first year of lactation, there is a paucity of data regarding human milk composition beyond one year postpartum. Policies vary at milk banks around the world regarding how long lactating women are eligible to donate their milk. The primary purpose of this study is to describe longitudinal changes in human milk composition in the second year postpartum to support the development of evidence based guidelines regarding how long lactating women can donate human milk to a milk bank. Nineteen lactating women in North Carolina provided monthly milk samples from 11 months to 17 months postpartum (N = 131), and two non-profit milk banks provided (N = 33) pooled, unpasteurized milk samples from 51 approved donors less than one year postpartum. There was a significant increase (P < 0.05) in the concentration of total protein, lactoferrin, lysozyme, Immunoglobulin A, oligosaccharides and sodium in longitudinal samples of mother's milk between 11 and 17 months postpartum, while zinc and calcium concentrations declined, and no changes were observed in lactose, fat, iron and potassium. Human milk in the second year postpartum contained significantly higher concentrations of total protein, lactoferrin, lysozyme and Immunoglobulin A, than milk bank samples, and significantly lower concentrations of zinc, calcium, iron and oligosaccharides. Accepting milk bank donations beyond one year postpartum is a potential strategy for increasing the supply of donor milk, but may require mineral fortification. © 2016 John Wiley & Sons Ltd.

Estimates of post-acceleration longitudinal bunch compression

International Nuclear Information System (INIS)

Judd, D.L.

1977-01-01

A simple analytic method is developed, based on physical approximations, for treating transient implosive longitudinal compression of bunches of heavy ions in an accelerator system for ignition of inertial-confinement fusion pellet targets. Parametric dependences of attainable compressions and of beam path lengths and times during compression are indicated for ramped pulsed-gap lines, rf systems in storage and accumulator rings, and composite systems, including sections of free drift. It appears that for high-confidence pellets in a plant producing 1000 MW of electric power the needed pulse lengths cannot be obtained with rings alone unless an unreasonably large number of them are used, independent of choice of rf harmonic number. In contrast, pulsed-gap lines alone can meet this need. The effects of an initial inward compressive drift and of longitudinal emittance are included

Macular function and morphologic features in juvenile stargardt disease: longitudinal study.

Science.gov (United States)

Testa, Francesco; Melillo, Paolo; Di Iorio, Valentina; Orrico, Ada; Attanasio, Marcella; Rossi, Settimio; Simonelli, Francesca

2014-12-01

To evaluate disease progression in a cohort of patients with a clinical and genetic diagnosis of Stargardt disease. Longitudinal cohort study. A total of 56 selected patients with a clinical and molecular diagnosis of Stargardt disease, an early age of onset, and a median follow-up length of 2 years. Patients underwent routine examination, including full-field electroretinography, microperimetry, and optical coherence tomography. Best-corrected visual acuity (BCVA), mean retinal sensitivity, fixation stability, preferred retinal locus, inner segment/outer segment (IS/OS) junction loss, and atrophic lesion area. A total of 56 patients with a mean age at disease onset of 15.3 years (range, 3-28 years), a mean disease duration of 12.1 years, and a mean age at baseline of 27.4 years were analyzed. The median BCVA was 20/200 in both eyes. Optical coherence tomography parameters (IS/OS alteration and retinal pigment epithelium lesion area) were obtained in only 49 patients because the signal quality was poor in the remaining 7 patients. Optical coherence tomography revealed a mean retinal pigment epithelium lesion area of 2.6 mm(2), preserved foveal IS/OS in 4.1% of patients, loss of foveal IS/OS in 59.2% of patients, and extensive loss of macular IS/OS in 36.7% of patients. Microperimetric findings showed a reduced macular sensitivity (mean, 10 decibels [dB]) and an unstable fixation in half of the patient cohort. The longitudinal analysis showed a significant progressive reduction of BCVA and macular sensitivity (at an estimated rate of 0.04 decimals and 1.19 dB/year, respectively) associated with a significant enlargement of retinal pigment epithelium lesion area (0.282 mm(2)/year). No significant changes in ophthalmoscopic findings and electroretinographic responses were detected. This study highlights the importance of microperimetry and optical coherence tomography in monitoring patients with Stargardt disease. Quantifying the decline of visual functionality and

A Primer on Longitudinal Data Analysis in Education. Technical Report #1320

Science.gov (United States)

Nese, Joseph F. T.; Lai, Cheng-Fei; Anderson, Daniel

2013-01-01

Longitudinal data analysis in education is the study growth over time. A longitudinal study is one in which repeated observations of the same variables are recorded for the same individuals over a period of time. This type of research is known by many names (e.g., time series analysis or repeated measures design), each of which can imply subtle…

Fitting the Fractional Polynomial Model to Non-Gaussian Longitudinal Data

Directory of Open Access Journals (Sweden)

Ji Hoon Ryoo

2017-08-01

Full Text Available As in cross sectional studies, longitudinal studies involve non-Gaussian data such as binomial, Poisson, gamma, and inverse-Gaussian distributions, and multivariate exponential families. A number of statistical tools have thus been developed to deal with non-Gaussian longitudinal data, including analytic techniques to estimate parameters in both fixed and random effects models. However, as yet growth modeling with non-Gaussian data is somewhat limited when considering the transformed expectation of the response via a linear predictor as a functional form of explanatory variables. In this study, we introduce a fractional polynomial model (FPM that can be applied to model non-linear growth with non-Gaussian longitudinal data and demonstrate its use by fitting two empirical binary and count data models. The results clearly show the efficiency and flexibility of the FPM for such applications.

Longitudinal motivational predictors of dietary self-care and diabetes control in adults with newly diagnosed type 2 diabetes mellitus.

Science.gov (United States)

Nouwen, Arie; Ford, Teri; Balan, Andreea Teodora; Twisk, Jos; Ruggiero, Laurie; White, David

2011-11-01

This prospective study examined relationships between constructs from social-cognitive theory (Bandura, 1986) and self-determination theory (Deci & Ryan, 1985; Deci & Ryan, 1991) and the diabetes outcomes of dietary self-care and diabetes control. Longitudinal data were collected from 237 people newly diagnosed with Type 2 diabetes who filled in questionnaires on dietary self-care, and motivational factors derived from social-cognitive theory and self-determination theory. Blood samples were taken to assess diabetes control (HbA1c). Repeated measurements were taken every 3-4 months for a total of five time points over 18 months. Predictor measures included autonomy support, autonomous and controlled motivation, amotivation, dietary self-efficacy, positive and negative outcome expectancies for dietary self-care and self-evaluation. Age, sex, BMI, and diabetes knowledge were included as control measures. Using Generalized Estimating Equations (GEE) analyses two models were tested: a standard model reflecting longitudinal associations between absolute values of predicted and outcome variables; and a change model examining motivational predictors of changes over time in diabetes outcomes of dietary self-care and diabetes control (HbA1c). Dietary self-care was longitudinally associated with self-efficacy, self-evaluation (the strongest predictor) autonomy support and autonomous motivation, but not with controlled motivation or outcome expectancies. Changes in dietary self-care were predicted by changes in self-efficacy, self-evaluation, and controlled motivation but not by changes in autonomous motivation or autonomy support. Negative outcome expectancies regarding diet were longitudinally associated with HbA1c, and changes in negative outcome expectancies predicted changes in HbA1c. However, there were indications that dietary self-care predicted changes in HbA1c. The results indicate that autonomy support, self-efficacy and, in particular, self-evaluation are key

Longitudinal changes over 2 years in parotid glands of patients treated with preoperative 30-Gy irradiation for oral cancer

International Nuclear Information System (INIS)

Tomitaka, Etsushi; Murakami, Ryuji; Teshima, Keiko

2011-01-01

The objective of this study was to evaluate longitudinal changes in parotid volumes and saliva production over 2 years after 30 Gy irradiation. We retrospectively evaluated 15 assessable patients treated for advanced oral cancer. Eligibility criteria were a pathologic diagnosis of squamous cell carcinoma, preoperative radiation therapy with a total dose of 30 Gy delivered in 15 fractions, and the availability of longitudinal data of morphological assessments by computed tomography and functional assessments with the Saxon test spanning 2 years after radiation therapy. In the Saxon test, saliva production was measured by weighing a folded sterile gauze pad before and after chewing; the low-normal value is 2 g/2 min. Repeated-measures analysis of variance with Bonferroni adjustment for multiple comparisons was used to determine the longitudinal changes. The normalized ipsilateral parotid volumes 2 weeks and 6-, 12- and 24 months after radiation therapy were found to be 72.5, 63.7, 66.9 and 78.1%, respectively; the normalized contralateral volumes were 69.8, 64.6, 72.2 and 82.0%, respectively. The bilateral parotid volumes were significantly decreased after radiation therapy (P<0.01). The nadir appeared at 6 months post-radiation therapy and the volumes substantially recuperated 24 months after radiation therapy (P<0.01). Mean saliva production before radiation therapy was 3.7 g; the longitudinal changes after radiation therapy were 31.3, 38.0, 43.3 and 69.6%, respectively. Substantial recuperation of saliva production was observed 24 months after radiation therapy (P=0.01). Although parotid volumes and saliva production were decreased after 30 Gy irradiation, we observed the recuperation of morphological and functional changes in the parotid glands 2 years after radiation therapy. (author)

Neurotransmitter implications in descending motility of longitudinal and circular muscles in rat colon

Directory of Open Access Journals (Sweden)

Zornitsa V. Gorcheva

2018-03-01

Full Text Available Introduction. The role of neurotransmitter systems in the motor activity of longitudinal or circular muscles in autonomic regulation of the motility of the colon by the nervous system is unclear. The aim of the study was to investigate the neurotransmitter implications in descending motility of longitudinal and circular muscles in rat colon. Methods. Electrically-induced (2, 5 or 10 Hz, 0.8 ms, 40 V, 20 s local or descending motor responses of longitudinal and circular muscles in isolated preparations and drugs were used to define the neurotransmitters’ role in colonic motility. Results. The spontaneous activity of the distal part of preparations manifested as high-amplitude irregular contractions more expressed in the longitudinal muscles. The electrically-induced local responses differed considerably in the two muscles: in longitudinal muscle there were frequency-dependent contractions, while initial relaxation followed by contraction was observed in circular muscle. The descending motor response resembled the pattern of the local responses, but the amplitudes were significantly less expressed, as compared to the respective local responses.

Longitudinal bulk a coustic mass sensor

DEFF Research Database (Denmark)

Hales, Jan Harry; Teva, Jordi; Boisen, Anja

2009-01-01

Design, fabrication and characterization, in terms of mass sensitivity, is presented for a polycrystalline silicon longitudinal bulk acoustic cantilever. The device is operated in air at 51 MHz, resulting in a mass sensitivity of 100 HZ/fg (1 fg = 10{su−15 g). The initial characterization is cond...

Numerical Modeling of Transient Heat Transfer in Longitudinal Fin

Directory of Open Access Journals (Sweden)

Farshad Panahizadeh

2017-11-01

Full Text Available The main objective of the present numerical study is to investigate the transient heat transfer in one kind of all-purpose longitudinal fin with the triangular profile. The lateral surface of the concerned fin and the tip of it are subjected to general situations included heat flux at the base and insulation on the tip. For this study developed a one dimensional in house code written by Fortran 90 programming language by using finite difference method with an implicit scheme in unsteady state condition. Generally, the result of this study in time variation state after 700 seconds is steady. The results also show the fin efficiency by increasing the time of study decreases due to a reduction in the total heat transfer which is happened in the fin. The grid independence study shows that for the number of nodes greater than 20 the result will not be changed and same as before. Finally, the result of Fortran code verified by commercial CFD code which relies on finite difference method and it was shown have a consistent agreement

On some properties of longitudinal and transverse coupled-bunch instabilities

International Nuclear Information System (INIS)

Kamiya, Yukihide.

1983-02-01

Some properties of longitudinal and transverse coupled-bunch instabilities have been investigated theoretically and computationally, mainly based on a rigid-bunch model. In this report, we will study Robinson's stability, sum rules of the instabilities and the cure of instabilities by producing the oscillation frequencies different from bunch to bunch, and also give the numerical examples for KEK-PF storage ring. KEYWORD: storage ring, accelerator, bunched beam, longitudinal instability, transverse instability, coupled-bunch instability. (author)

Multiobjective Optimal Control of Longitudinal Seismic Response of a Multitower Cable-Stayed Bridge

Directory of Open Access Journals (Sweden)

Geng Fangfang

2016-01-01

Full Text Available The dynamic behavior of a multitower cable-stayed bridge with the application of partially longitudinal constraint system using viscous fluid dampers under real earthquake ground motions is presented. The study is based on the dynamic finite element model of the Jiashao Bridge, a six-tower cable-stayed bridge in China. The prime aim of the study is to investigate the effectiveness of viscous fluid dampers on the longitudinal seismic responses of the bridge and put forth a multiobjective optimization design method to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multitower cable-stayed bridge with the partially longitudinal constraint system is to yield maximum reductions in the base forces of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base forces of bridge towers longitudinally unrestricted with the bridge deck. To this end, a multiobjective optimization design method that uses a nondominating sort genetic algorithm II (NSGA-II is used to optimize parameters of the viscous fluid dampers. The effectiveness of the proposed optimization design method is demonstrated for the multitower cable-stayed bridge with the partially longitudinal constraint system, which reveals that a design engineer can choose a set of proper parameters of the viscous fluid dampers from Pareto optimal fronts that can satisfy the desired performance requirements.

Comparative analysis of maximum renal longitudinal length with positional changes on ultrasound with multiplanar reconstructed MR image in Korea Adults

International Nuclear Information System (INIS)

Jang, Yun Hee; Cho, Bum Sang; Kang, Min Ho; Kang, Woo Young; Lee, Jisun; Kim, Yook; Lee, Soo Hyun; Lee, Soo Jung; Lee, Jin Yong

2016-01-01

The purpose of this study was to determine a suitable position in which the measured length on ultrasound is close to the true renal length obtained through a multiplanar reconstructed MR image. A total of 33 individuals (males: 15, females: 18) without any underlying renal disease were included in the present study. Renal length was measured as the longest axis at the level of the renal hilum in three positions-supine, lateral decubitus, and prone, respectively. With a 3.0 T MR scanner, 3D eTHRIVE was acquired. Subsequently, the maximum longitudinal length of both the kidneys was measured through multiplanar reconstructed MR images. Paired t-test was used to compare the renal length obtained from ultrasonographic measurement with the length obtained through multiplanar reconstructed MR images. Our study demonstrated significant difference between sonographic renal length in three positions and renal length through MRI (p < 0.001). However, the longest longitudinal length of right kidney among the measured three values by ultrasound was statistically similar to the renal length measured by reconstructed MR image. Among them, the lateral decubitus position showed the strongest correlation with true renal length (right: 0.887; left: 0.849). We recommend measurement of the maximum renal longitudinal length in all possible positions on ultrasonography. If not allowed, the best measurement is on the lateral decubitus showing the strongest correlation coefficient with true renal length

Comparative analysis of maximum renal longitudinal length with positional changes on ultrasound with multiplanar reconstructed MR image in Korea Adults

Energy Technology Data Exchange (ETDEWEB)

Jang, Yun Hee; Cho, Bum Sang; Kang, Min Ho; Kang, Woo Young; Lee, Jisun; Kim, Yook; Lee, Soo Hyun; Lee, Soo Jung [Dept. of Radiology, Chungbuk National University Hospital, Cheongju (Korea, Republic of); Lee, Jin Yong [Public Health Medical Service, Seoul National University Boramae Medical Center, Seoul (Korea, Republic of)

2016-07-15

The purpose of this study was to determine a suitable position in which the measured length on ultrasound is close to the true renal length obtained through a multiplanar reconstructed MR image. A total of 33 individuals (males: 15, females: 18) without any underlying renal disease were included in the present study. Renal length was measured as the longest axis at the level of the renal hilum in three positions-supine, lateral decubitus, and prone, respectively. With a 3.0 T MR scanner, 3D eTHRIVE was acquired. Subsequently, the maximum longitudinal length of both the kidneys was measured through multiplanar reconstructed MR images. Paired t-test was used to compare the renal length obtained from ultrasonographic measurement with the length obtained through multiplanar reconstructed MR images. Our study demonstrated significant difference between sonographic renal length in three positions and renal length through MRI (p < 0.001). However, the longest longitudinal length of right kidney among the measured three values by ultrasound was statistically similar to the renal length measured by reconstructed MR image. Among them, the lateral decubitus position showed the strongest correlation with true renal length (right: 0.887; left: 0.849). We recommend measurement of the maximum renal longitudinal length in all possible positions on ultrasonography. If not allowed, the best measurement is on the lateral decubitus showing the strongest correlation coefficient with true renal length.

Longitudinal multigroup invariance analysis of the satisfaction with food-related life scale in university students

DEFF Research Database (Denmark)

Schnettler, Berta; Miranda, Horacio; Miranda-Zapata, Edgardo

2017-01-01

This study examined longitudinal measurement invariance in the Satisfaction with Food-related Life (SWFL) scale using follow-up data from university students. We examined this measure of the SWFL in different groups of students, separated by various characteristics. Through non......-probabilistic longitudinal sampling, 114 university students (65.8% female, mean age: 22.5) completed the SWFL questionnaire three times, over intervals of approximately one year. Confirmatory factor analysis was used to examine longitudinal measurement invariance. Two types of analysis were conducted: first, a longitudinal...... students of both sexes, and among those older and younger than 22 years. Generally, these findings suggest that the SWFL scale has satisfactory psychometric properties for longitudinal measurement invariance in university students with similar characteristics as the students that participated...

Longitudinal Alterations of Frontoparietal and Frontotemporal Networks Predict Future Creative Cognitive Ability.

Science.gov (United States)

Chen, Qunlin; Beaty, Roger E; Wei, Dongtao; Yang, Junyi; Sun, Jiangzhou; Liu, Wei; Yang, Wenjing; Zhang, Qinglin; Qiu, Jiang

2018-01-01

Creative cognition is important to academic performance and career success during late adolescence and adulthood. However, there is a lack of longitudinal data on whether brain structural development could predict improvements in creative thinking, and how such changes interact with other cognitive abilities to support creative performance. Here we examined longitudinal alterations of brain structure and their relation to creative cognitive ability in a sample of 159 healthy young adults who were scanned using magnetic resonance imaging 2-3 times over the course of 3 years. The most robust predictor of future creative ability was the right dorsolateral prefrontal cortex (DLPFC), which in conjunction with baseline creative capacity showed a 31% prediction rate. Longitudinal analysis revealed that slower decreases in gray matter density within left frontoparietal and right frontotemporal clusters predicted enhanced creative ability. Moreoever, the relationship between longitudinal alterations within frontal-related clusters and improved creative ability was moderated by the right DLPFC and working memory ability. We conclude that continuous goal-directed planning and accumulated knowledge are implemented in the right DLPFC and temporal areas, respectively, which in turn support longitudinal gains in creative cognitive ability. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

Science.gov (United States)

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

2014-01-01

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

Predicting longitudinal trajectories of health probabilities with random-effects multinomial logit regression.

Science.gov (United States)

Liu, Xian; Engel, Charles C

2012-12-20

Researchers often encounter longitudinal health data characterized with three or more ordinal or nominal categories. Random-effects multinomial logit models are generally applied to account for potential lack of independence inherent in such clustered data. When parameter estimates are used to describe longitudinal processes, however, random effects, both between and within individuals, need to be retransformed for correctly predicting outcome probabilities. This study attempts to go beyond existing work by developing a retransformation method that derives longitudinal growth trajectories of unbiased health probabilities. We estimated variances of the predicted probabilities by using the delta method. Additionally, we transformed the covariates' regression coefficients on the multinomial logit function, not substantively meaningful, to the conditional effects on the predicted probabilities. The empirical illustration uses the longitudinal data from the Asset and Health Dynamics among the Oldest Old. Our analysis compared three sets of the predicted probabilities of three health states at six time points, obtained from, respectively, the retransformation method, the best linear unbiased prediction, and the fixed-effects approach. The results demonstrate that neglect of retransforming random errors in the random-effects multinomial logit model results in severely biased longitudinal trajectories of health probabilities as well as overestimated effects of covariates on the probabilities. Copyright © 2012 John Wiley & Sons, Ltd.

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

Science.gov (United States)

Christakis, Panos G; Braga-Mele, Rosa M

2012-02-01

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

Executive function influences sedentary behavior: A longitudinal study

Directory of Open Access Journals (Sweden)

Paul D. Loprinzi

2016-10-01

Full Text Available Background: No study has evaluated the effects of executive function on follow-up sedentary behavior, which was this study’s purpose. Methods: A longitudinal design was employed among 18 young adult college students (Mage = 23.7 years; 88.9% female. Accelerometer-determined sedentary behavior and physical activity, along with executive function, were assessed at baseline. Approximately 8 weeks later, re-assessment of accelerometer-determined sedentary behavior and physical activity occurred. Executive function was assessed using the Parametric Go/No-Go (PGNG computer task. From this, 2 primary executive function outcome parameters were evaluated, including the Simple Rule and Repeating Rule. Results: After adjusting for baseline sedentary behavior, age, gender, body mass index and baseline moderate-to-vigorous physical activity (MVPA, for every 25% increase in the number of correctly identified targets for the Repeating rule at the baseline assessment, participants engaged in 91.8 fewer minutes of sedentary behavior at the follow-up assessment (β = -91.8; 95% CI: -173.5, -10.0; P = 0.03. Results were unchanged when also adjusting for total baseline or follow-up physical activity. Conclusion: Greater executive function is associated with less follow-up sedentary behavior.

Estudio longitudinal de anticuerpos anticitoplasma de neutrófilos en pacientes con anemia drepanocítica Longitudinal study of antineutrophil cytoplasmic antibodies in patients with sickle cell anemia

Directory of Open Access Journals (Sweden)

Ana María Guerreiro Hernández

2000-08-01

Full Text Available Se realizó un estudio longitudinal para detectar anticuerpos anticitoplasma de neutrófilos (ANCA en 13 pacientes con anemia drepanocítica en crisis vasooclusiva y en estado basal, mediante un método de inmunofluorescencia indirecta. Del total de 34 muestras de suero obtenidas, 16 fueron en crisis vasooclusiva y en 12 de ellas, correspondientes a 10 pacientes, se demostró la presencia de p-ANCA. En el resto de las muestras en crisis vasooclusiva y en estado basal no se observó la presencia de p-ANCA o c-ANCA. Los resultados obtenidos sugieren la posible participación de los p-ANCA en el daño isquémico, así como la importancia de su medición en el diagnóstico de las crisis vasooclusivas (CVO en los pacientes con anemia drepanocítica (ADA longitudinal study was made to detect antineutrophil cytoplasmic antibodies (ANCA in 13 patients with sickle cell anemia in vasocclusive crisis and basal state by using an indirect immunofluorescence method. Of 34 serum samples, 16 were in vasocclusive crisis and 12 of them corresponding to 10 patients revealed the presence of p-ANCA. Neither p-ANCA nor c-ANCA was observed in the rest of the samples taken in vasoclussive crisis and in basal state. The results achieved signaled a possible involvement of p-ANCA in ischemic damage as well as the importance of their measurement in the diagnosis of vasocclusive crisis in patients with sickle cell anemia

Longitudinal data analysis in support of functional stability concepts for leachate management at closed municipal landfills

International Nuclear Information System (INIS)

Gibbons, Robert D.; Morris, Jeremy W.F.; Prucha, Christopher P.; Caldwell, Michael D.; Staley, Bryan F.

2014-01-01

Highlights: • Longitudinal data analysis using a mixed-effects regression model. • Dataset consisted of a total of 1402 samples from 101 closed municipal landfills. • Target analytes and classes generally showed predictable degradation trends. • Validates historical studies focused on macro organic indicators such as BOD. • BOD can serve as “gateway” indicator for planning leachate management. - Abstract: Landfill functional stability provides a target that supports no environmental threat at the relevant point of exposure in the absence of active control systems. With respect to leachate management, this study investigates “gateway” indicators for functional stability in terms of the predictability of leachate characteristics, and thus potential threat to water quality posed by leachate emissions. Historical studies conducted on changes in municipal solid waste (MSW) leachate concentrations over time (longitudinal analysis) have concentrated on indicator compounds, primarily chemical oxygen demand (COD) and biochemical oxygen demand (BOD). However, validation of these studies using an expanded database and larger constituent sets has not been performed. This study evaluated leachate data using a mixed-effects regression model to determine the extent to which leachate constituent degradation can be predicted based on waste age or operational practices. The final dataset analyzed consisted of a total of 1402 samples from 101 MSW landfills. Results from the study indicated that all leachate constituents exhibit a decreasing trend with time in the post-closure period, with 16 of the 25 target analytes and aggregate classes exhibiting a statistically significant trend consistent with well-studied indicators such as BOD. Decreasing trends in BOD concentration after landfill closure can thus be considered representative of trends for many leachate constituents of concern

Longitudinal data analysis in support of functional stability concepts for leachate management at closed municipal landfills

Energy Technology Data Exchange (ETDEWEB)

Gibbons, Robert D., E-mail: rdg@uchicago.edu [Center for Health Statistics, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637 (United States); Morris, Jeremy W.F., E-mail: jmorris@geosyntec.com [Geosyntec Consultants, 10220 Old Columbia Road, Suite A, Columbia, MD 21046 (United States); Prucha, Christopher P., E-mail: cprucha@wm.com [Groundwater Protection Program, Waste Management, 1550 Balmer Road, Box 200, Model City, NY 14107 (United States); Caldwell, Michael D., E-mail: mcaldwell@wm.com [Groundwater Protection Program, Waste Management, 3623 Wilson Road, Humble, TX 77396 (United States); Staley, Bryan F., E-mail: BStaley@erefdn.org [Environmental Research and Education Foundation, 3301 Benson Drive, Suite 301, Raleigh, NC 27609 (United States)

2014-09-15

Highlights: • Longitudinal data analysis using a mixed-effects regression model. • Dataset consisted of a total of 1402 samples from 101 closed municipal landfills. • Target analytes and classes generally showed predictable degradation trends. • Validates historical studies focused on macro organic indicators such as BOD. • BOD can serve as “gateway” indicator for planning leachate management. - Abstract: Landfill functional stability provides a target that supports no environmental threat at the relevant point of exposure in the absence of active control systems. With respect to leachate management, this study investigates “gateway” indicators for functional stability in terms of the predictability of leachate characteristics, and thus potential threat to water quality posed by leachate emissions. Historical studies conducted on changes in municipal solid waste (MSW) leachate concentrations over time (longitudinal analysis) have concentrated on indicator compounds, primarily chemical oxygen demand (COD) and biochemical oxygen demand (BOD). However, validation of these studies using an expanded database and larger constituent sets has not been performed. This study evaluated leachate data using a mixed-effects regression model to determine the extent to which leachate constituent degradation can be predicted based on waste age or operational practices. The final dataset analyzed consisted of a total of 1402 samples from 101 MSW landfills. Results from the study indicated that all leachate constituents exhibit a decreasing trend with time in the post-closure period, with 16 of the 25 target analytes and aggregate classes exhibiting a statistically significant trend consistent with well-studied indicators such as BOD. Decreasing trends in BOD concentration after landfill closure can thus be considered representative of trends for many leachate constituents of concern.

Longitudinal Predictors of High School Completion

Science.gov (United States)

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%…

Teaching Technology Longitudinally to Virtual Children

Science.gov (United States)

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.…

Energy dissipation by a longitudinal Raman process

International Nuclear Information System (INIS)

Fano, U.; Inokuti, Mitio

1994-01-01

The concept of a longitudinal Raman process is introduced to encompass the indirect transmission of energy from slow electrons to nuclei through the reversible polarization of surrounding electrons. Experimental approaches are sought to assess this process quantitatively

Longitudinal Profiles of Adaptive Behavior in Fragile X Syndrome

Science.gov (United States)

Quintin, Eve-Marie; Jo, Booil; Lightbody, Amy A.; Hazlett, Heather Cody; Piven, Joseph; Hall, Scott S.; Reiss, Allan L.

2014-01-01

OBJECTIVE: To examine longitudinally the adaptive behavior patterns in fragile X syndrome. METHOD: Caregivers of 275 children and adolescents with fragile X syndrome and 225 typically developing children and adolescents (2–18 years) were interviewed with the Vineland Adaptive Behavior Scales every 2 to 4 years as part of a prospective longitudinal study. RESULTS: Standard scores of adaptive behavior in people with fragile X syndrome are marked by a significant decline over time in all domains for males and in communication for females. Socialization skills are a relative strength as compared with the other domains for males with fragile X syndrome. Females with fragile X syndrome did not show a discernible pattern of developmental strengths and weaknesses. CONCLUSIONS: This is the first large-scale longitudinal study to show that the acquisition of adaptive behavior slows as individuals with fragile X syndrome age. It is imperative to ensure that assessments of adaptive behavior skills are part of intervention programs focusing on childhood and adolescence in this condition. PMID:25070318

Longitudinal Research in Social Science: Some Theoretical Challenges

Directory of Open Access Journals (Sweden)

Thomas K. Burch

2001-12-01

Full Text Available Every advance carries with it potential problems, and longitudinal analysis is no exception. This paper focuses on the problems related to the massive amounts of data generated by longitudinal surveys. It is argued that a proliferation of data may be to the good but it will not necessarily lead to better scientific knowledge. Most demographers think the logical positivist way that theory arises out of empirical generalisations, but massive empirical investigations have only led to disappointing theoretical outcomes in demography. This paper discusses one way out of this impasse - to adopt a different view of theory, a model-based view of science. Theoretical models based on empirical generalisation should become the main representational device in science.

Antiferromagnetic Ising model with transverse and longitudinal field

International Nuclear Information System (INIS)

Kischinhevsky, M.

1985-01-01

We study the quantum hamiltonian version of the Ising Model in one spacial dimension under an external longitudinal (uniform) field at zero temperature. A phenomenological renormalization group procedure is used to obtain the phase diagram; the transverse and longitudinal zero field limits are studied and we verify the validity of universality at non zero transverse fields, where two-dimensional critical behaviour is obtained. To perform the numerical calculations we use the Lanczos scheme, which gives highly precise results with rather short processing times. We also analyse the possibility of using these techniques to extend the present work to the quantum hamiltonian version of the q-state Potts Model (q>2) in larger system. (author) [pt

Age-related slowing of digit symbol substitution revisited: what do longitudinal age changes reflect?

Science.gov (United States)

MacDonald, Stuart W S; Hultsch, David F; Strauss, Esther; Dixon, Roger A

2003-05-01

A previous investigation reported that cross-sectional age differences in Digit Symbol Substitution (DSS) test performance reflect declines in perceptual processing speed. Support for the tenability of the processing speed hypothesis requires examining whether longitudinal age-related change in DSS performance is largely mediated by changes in speed. The present study used data from the Victoria Longitudinal Study to examine patterns and predictors of longitudinal change in DSS for 512 older adults (M(age) = 68.37 years, SD = 7.43). On the basis of multilevel modeling, baseline DSS performance was poorer for older participants and men, with longitudinal declines more pronounced with increasing age and decreasing speed. In contrast to the present cross-sectional findings, statistical control of change trajectories in perceptual speed using the same data did not substantially attenuate age changes. These discrepancies suggest different sources of variance may underlie cross-sectional age differences and longitudinal age changes for DSS.

Control of longitudinal collective behavior in the Muon Collider rings

International Nuclear Information System (INIS)

Cheng, Wen-Hao

1997-05-01

The longitudinal bunch collective effects in a Muon Collider ring are theoretically examined. The situation involves an intense bunch, a short bunch, a small momentum compaction, a rather large impedance compared with the stability threshold criterion, and luminosity life time limited by muon decay to a thousand turns. Qualitative descriptions of stability are given and a scaling law for the instability threshold is derived. Numerical simulation results for the impedance-related instabilities are given for two cases of current interest - a 250 GeV x 250 GeV demonstration machine and a 2 TeV x 2 TeV high energy machine. The results of these simulations are in good agreement with the predictions of the scaling law and show that the longitudinal collective effects are controllable with a proper choice of parameters (viz. rf voltage, rf frequency, linear and non-linear longitudinal chromaticity)

Longitudinal Predictors of Chinese Word Reading and Spelling among Elementary Grade Students

Science.gov (United States)

Yeung, Pui-Sze; Ho, Connie Suk-Han; Wong, Yau-Kai; Chung, Kevin Kien-Hoa; Lo, Lap-Yan

2013-01-01

The longitudinal predictive power of four important reading-related skills (phonological skills, rapid naming, orthographic skills, and morphological awareness) to Chinese word reading and writing to dictation (i.e., spelling) was examined in a 3-year longitudinal study among 251 Chinese elementary students. Rapid naming, orthographic skills, and…

Mathematics Anxiety in Young Children: Concurrent and Longitudinal Associations with Mathematical Performance

Science.gov (United States)

Vukovic, Rose K.; Kieffer, Michael J.; Bailey, Sean P.; Harari, Rachel R.

2013-01-01

This study explored mathematics anxiety in a longitudinal sample of 113 children followed from second to third grade. We examined how mathematics anxiety related to different types of mathematical performance concurrently and longitudinally and whether the relations between mathematics anxiety and mathematical performance differed as a function of…

Estimators for longitudinal latent exposure models: examining measurement model assumptions.

Science.gov (United States)

Sánchez, Brisa N; Kim, Sehee; Sammel, Mary D

2017-06-15

Latent variable (LV) models are increasingly being used in environmental epidemiology as a way to summarize multiple environmental exposures and thus minimize statistical concerns that arise in multiple regression. LV models may be especially useful when multivariate exposures are collected repeatedly over time. LV models can accommodate a variety of assumptions but, at the same time, present the user with many choices for model specification particularly in the case of exposure data collected repeatedly over time. For instance, the user could assume conditional independence of observed exposure biomarkers given the latent exposure and, in the case of longitudinal latent exposure variables, time invariance of the measurement model. Choosing which assumptions to relax is not always straightforward. We were motivated by a study of prenatal lead exposure and mental development, where assumptions of the measurement model for the time-changing longitudinal exposure have appreciable impact on (maximum-likelihood) inferences about the health effects of lead exposure. Although we were not particularly interested in characterizing the change of the LV itself, imposing a longitudinal LV structure on the repeated multivariate exposure measures could result in high efficiency gains for the exposure-disease association. We examine the biases of maximum likelihood estimators when assumptions about the measurement model for the longitudinal latent exposure variable are violated. We adapt existing instrumental variable estimators to the case of longitudinal exposures and propose them as an alternative to estimate the health effects of a time-changing latent predictor. We show that instrumental variable estimators remain unbiased for a wide range of data generating models and have advantages in terms of mean squared error. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Measurement of high-Q{sup 2} charged current deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA

Energy Technology Data Exchange (ETDEWEB)

Abramowicz, H. [Tel Aviv Univ. (Israel). Faculty of Exact Sciences, School of Physics; Max-Planck-Inst., Munich (Germany); Abt, I. [Max-Planck-Inst. fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

2010-08-15

Measurements of the cross sections for charged current deep inelastic scattering in e{sup +}p collisions with a longitudinally polarised positron beam are presented. The measurements are based on a data sample with an integrated luminosity of 132 pb{sup -1} collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the positron beams. The single-differential cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy are presented for Q{sup 2}>200 GeV{sup 2}. The reduced cross-section {sigma} is presented in the kinematic range 200

Measurement of Pion and Proton Response and Longitudinal Shower Profiles up to 20 Nuclear Interaction Lengths with the ATLAS Tile Calorimeter

CERN Document Server

Adragna, P; Anderson, K; Antonaki, A; Arabidze, A; Batkova, L; Batusov, V; Beck, H P; Bergeaas Kuutmann, E; Biscarat, C; Blanchot, G; Bogush, A; Bohm, C; Boldea, V; Bosman, M; Bromberg, C; Budagov, J; Burckhart-Chromek, D; Caprini, M; Caloba, L; Calvet, D; Carli, T; Carvalho, J; Cascella, M; Castelo, J; Castillo, M V; Cavalli-Sforza, M; Cavasinni, V; Cerqueira, A S; Clement, C; Cobal, M; Cogswell, F; Constantinescu, S; Costanzo, D; Corso-Radu, A; Cuenca, C; Damazio, D O; Davidek, T; De, K; Del Prete, T; Di Girolamo, B; Dita, S; Djobava, T; Dobson, M; Dotti, A; Downing, R; Efthymiopoulos, I; Eriksson, D; Errede, D; Errede, S; Farbin, A; Fassouliotis, D; Febbraro, R; Fenyuk, A; Ferdi, C; Ferrer, A; Flaminio, V; Francis, D; Fullana, E; Gadomski, S; Gameiro, S; Garde, V; Gellerstedt, K; Giakoumopoulou, V; Gildemeister, O; Gilewsky, V; Giokaris, N; Gollub, N; Gomes, A; Gonzalez, V; Gorini, B; Grenier, P; Gris, P; Gruwe, M; Guarino, V; Guicheney, C; Gupta, A; Haeberli, C; Hakobyan, H; Haney, M; Hellman, S; Henriques, A; Higon, E; Holmgren, S; Hurwitz, M; Huston, J; Iglesias, C; Isaev, A; Jen-La Plante, I; Jon-And, K; Joos, M; Junk, T; Karyukhin, A; Kazarov, A; Khandanyan, H; Khramov, J; Khubua, J; Kolos, S; Korolkov, I; Krivkova, P; Kulchitsky, Y; Kurochkin, Yu; Kuzhir, P; LeCompte, T; Lefevre, R; Lehmann, G; Leitner, R; Lembesi, M; Lesser, J; Li, J; Liablin, M; Lokajicek, M; Lomakin, Y; Lupi, A; Maidanchik, C; Maio, A; Makouski, M; Maliukov, S; Manousakis, A; Mapelli, L; Marques, C; Marroquim, F; Martin, F; Mazzoni, E; Merritt, F; Miagkov, A; Miller, R; Minashvili, I; Miralles, L; Montarou, G; Mosidze, M; Myagkov, A; Nemecek, S; Nessi, M; Nodulman, L; Nordkvist, B; Norniella, O; Novakova, J; Onofre, A; Oreglia, M; Pallin, D; Pantea, D; Petersen, J; Pilcher, J; Pina, J; Pinhao, J; Podlyski, F; Portell Bueso, X; Poveda, J; Pribyl, L; Price, L E; Proudfoot, J; Ramstedt, M; Richards, R; Roda, C; Romanov, V; Rosnet, P; Roy, P; Ruiz, A; Rumiantsev, V; Russakovich, N; Salto, O; Salvachua, B; Sanchis, E; Sanders, H; Santoni, C; Saraiva, J G; Sarri, F; Satsunkevitch, I; Says, L P; Schlager, G; Schlereth, J; Seixas, J M; Sellden, B; Shalanda, N; Shevtsov, P; Shochet, M; Silva, J; Da Silva, P; Simaitis, V; Simonyan, M; Sissakian, A; Sjolin, J; Solans, C; Solodkov, A; Soloviev, I; Solovyanov, O; Sosebee, M; Spano, F; Stanek, R; Starchenko, E; Starovoitov, P; Stavina, P; Suk, M; Sykora, I; Tang, F; Tas, P; Teuscher, R; Tokar, S; Topilin, N; Torres, J; Tremblet, L; Tsiareshka, P; Tylmad, M; Underwood, D; Unel, G; Usai, G; Valero, A; Valkar, S; Valls, J A; Vartapetian, A; Vazeille, F; Vichou, I; Vinogradov, V; Vivarelli, I; Volpi, M; White, A; Zaitsev, A; Zenine, A; Zenis, T

2010-01-01

The response of pions and protons in the energy range of 20 to 180 GeV produced at CERN's SPS H8 test beam line in the ATLAS iron-scintillator Tile hadron calorimeter has been measured. The test-beam configuration allowed to measure the longitudinal shower development for pions and protons up to 20 nuclear interaction lengths. It is found that pions penetrate deeper in the calorimeter than protons. However, protons induce showers that are wider laterally to the direction of the impinging particle. Including the measured total energy response, the pion to proton energy ratio and the resolution, all observations are consistent with a higher electromagnetic energy fraction in pion induced showers. The data are compared with GEANT4 simulations using several hadronic physics lists. The measured longitudinal shower profiles are described by an analytical shower parameterization within an accuracy of 5-10%. The amount of energy leaking out behind the calorimeter is determined and parameterised as a function of the b...

Kidney function changes with aging in adults: comparison between cross-sectional and longitudinal data analyses in renal function assessment.

Science.gov (United States)

Chung, Sang M; Lee, David J; Hand, Austin; Young, Philip; Vaidyanathan, Jayabharathi; Sahajwalla, Chandrahas

2015-12-01

The study evaluated whether the renal function decline rate per year with age in adults varies based on two primary statistical analyses: cross-section (CS), using one observation per subject, and longitudinal (LT), using multiple observations per subject over time. A total of 16628 records (3946 subjects; age range 30-92 years) of creatinine clearance and relevant demographic data were used. On average, four samples per subject were collected for up to 2364 days (mean: 793 days). A simple linear regression and random coefficient models were selected for CS and LT analyses, respectively. The renal function decline rates per year were 1.33 and 0.95 ml/min/year for CS and LT analyses, respectively, and were slower when the repeated individual measurements were considered. The study confirms that rates are different based on statistical analyses, and that a statistically robust longitudinal model with a proper sampling design provides reliable individual as well as population estimates of the renal function decline rates per year with age in adults. In conclusion, our findings indicated that one should be cautious in interpreting the renal function decline rate with aging information because its estimation was highly dependent on the statistical analyses. From our analyses, a population longitudinal analysis (e.g. random coefficient model) is recommended if individualization is critical, such as a dose adjustment based on renal function during a chronic therapy. Copyright © 2015 John Wiley & Sons, Ltd.

A Longitudinal Analysis of the Influence of the Neighborhood Environment on Recreational Walking within the Neighborhood: Results from RESIDE.

Science.gov (United States)

Christian, Hayley; Knuiman, Matthew; Divitini, Mark; Foster, Sarah; Hooper, Paula; Boruff, Bryan; Bull, Fiona; Giles-Corti, Billie

2017-07-12

There is limited longitudinal evidence confirming the role of neighborhood environment attributes in encouraging people to walk more or if active people simply choose to live in activity-friendly neighborhoods. Natural experiments of policy changes to create more walkable communities provide stronger evidence for a causal effect of neighborhood environments on residents' walking. We aimed to investigate longitudinal associations between objective and perceived neighborhood environment measures and neighborhood recreational walking. We analyzed longitudinal data collected over 8 yr (four surveys) from the RESIDential Environments (RESIDE) Study (Perth, Australia, 2003-2012). At each time point, participants reported the frequency and total minutes of recreational walking/week within their neighborhood and neighborhood environment perceptions. Objective measures of the neighborhood environment were generated using a Geographic Information System (GIS). Local recreational walking was influenced by objectively measured access to a medium-/large-size park, beach access, and higher street connectivity, which was reduced when adjusted for neighborhood perceptions. In adjusted models, positive perceptions of access to a park and beach, higher street connectivity, neighborhood esthetics, and safety from crime were independent determinants of increased neighborhood recreational walking. Local recreational walking increased by 9 min/wk (12% increase in frequency) for each additional perceived neighborhood attribute present. Our findings provide urban planners and policy makers with stronger causal evidence of the positive impact of well-connected neighborhoods and access to local parks of varying sizes on local residents' recreational walking and health. https://doi.org/10.1289/EHP823.

Longitudinal study of arteriogenesis with swept source optical coherence tomography and hyperspectral imaging

Science.gov (United States)

Poole, Kristin M.; Patil, Chetan A.; Nelson, Christopher E.; McCormack, Devin R.; Madonna, Megan C.; Duvall, Craig L.; Skala, Melissa C.

2014-03-01

Peripheral arterial disease (PAD) is an atherosclerotic disease of the extremities that leads to high rates of myocardial infarction and stroke, increased mortality, and reduced quality of life. PAD is especially prevalent in diabetic patients, and is commonly modeled by hind limb ischemia in mice to study collateral vessel development and test novel therapies. Current techniques used to assess recovery cannot obtain quantitative, physiological data non-invasively. Here, we have applied hyperspectral imaging and swept source optical coherence tomography (OCT) to study longitudinal changes in blood oxygenation and vascular morphology, respectively, intravitally in the diabetic mouse hind limb ischemia model. Additionally, recommended ranges for controlling physiological variability in blood oxygenation with respect to respiration rate and body core temperature were determined from a control animal experiment. In the longitudinal study with diabetic mice, hyperspectral imaging data revealed the dynamics of blood oxygenation recovery distally in the ischemic footpad. In diabetic mice, there is an early increase in oxygenation that is not sustained in the long term. Quantitative analysis of vascular morphology obtained from Hessian-filtered speckle variance OCT volumes revealed temporal dynamics in vascular density, total vessel length, and vessel diameter distribution in the adductor muscle of the ischemic limb. The combination of hyperspectral imaging and speckle variance OCT enabled acquisition of novel functional and morphological endpoints from individual animals, and provides a more robust platform for future preclinical evaluations of novel therapies for PAD.

Collaborative Knowledge-Building: A Longitudinal Study

Science.gov (United States)

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…

The Merits of Using Longitudinal Mediation

Science.gov (United States)

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…

Physical Activity and Personality Development over Twenty Years: Evidence from Three Longitudinal Samples

Science.gov (United States)

Stephan, Yannick; Sutin, Angelina R.; Luchetti, Martina; Bosselut, Grégoire; Terracciano, Antonio

2018-01-01

A physically inactive lifestyle is associated with maladaptive patterns of personality development over relatively short follow-up periods. The present study extends existing research by examining whether this association persists over 20 years. Participants (total N = 8,723) were drawn from the Wisconsin Longitudinal Study Graduates and Siblings samples and the Midlife in the United States Study. Controlling for demographic factors and disease burden, baseline physical inactivity was related to steeper declines in conscientiousness in all three samples and a meta-analysis (β=−.06). The meta-analysis further showed that lower physical activity was associated with declines in openness (β=−.05), extraversion (β=−.03), and agreeableness (β=−.03). These findings provide evidence that a physically inactive lifestyle is associated with long-term detrimental personality trajectories. PMID:29651189

Longitudinal associations between adolescent perceived degree and style of parental prohibition and internalization and defiance.

Science.gov (United States)

Vansteenkiste, Maarten; Soenens, Bart; Van Petegem, Stijn; Duriez, Bart

2014-01-01

This study examined associations between perceived degree and style of parental prohibition and adolescents' internalization of and oppositional defiance against parental rules in the friendship and moral domain. Relations were investigated in 2 longitudinal adolescent samples (total N = 532). Results indicated that perceived style but not degree of prohibition related to overtime changes in internalization and oppositional defiance. Specifically, in line with self-determination theory, autonomy-supportive and controlling styles of prohibiting were found to relate differentially to quality of internalization and oppositional defiance. Cross-lagged analyses indicated that several of these associations were reciprocal. The discussion focuses on the critical role of perceived parental style for communicating prohibitions. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Physical activity and motor competence present a positive reciprocal longitudinal relationship across childhood and early adolescence

DEFF Research Database (Denmark)

Lima, Rodrigo A.; Pfeiffer, Karin; Larsen, Lisbeth R.

2017-01-01

Background: The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years. Methods: This was a 7-year longitudinal study, the Copenhagen School Child Intervent......Background: The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years. Methods: This was a 7-year longitudinal study, the Copenhagen School Child...

Analysis of Longitudinal Waves in Rod-Type Piezoelectric Phononic Crystals

Directory of Open Access Journals (Sweden)

Longfei Li

2016-04-01

Full Text Available Phononic crystals can be used to control elastic waves due to their frequency bands. This paper analyzes the passive and active control as well as the dispersion properties of longitudinal waves in rod-type piezoelectric phononic crystals over large frequency ranges. Based on the Love rod theory for modeling the longitudinal wave motions in the constituent rods and the method of reverberation-ray matrix (MRRM for deriving the member transfer matrices of the constituent rods, a modified transfer matrix method (MTMM is proposed for the analysis of dispersion curves by combining with the Floquet–Bloch principle and for the calculation of transmission spectra. Numerical examples are provided to validate the proposed MTMM for analyzing the band structures in both low and high frequency ranges. The passive control of longitudinal-wave band structures is studied by discussing the influences of the electrode’s thickness, the Poisson’s effect and the elastic rod inserts in the unit cell. The influences of electrical boundaries (including electric-open, applied electric capacity, electric-short and applied feedback control conditions on the band structures are investigated to illustrate the active control scheme. From the calculated comprehensive frequency spectra over a large frequency range, the dispersion properties of the characteristic longitudinal waves in rod-type piezoelectric phononic crystals are summarized.

Training, Innovation and Business Performance: An Analysis of the Business Longitudinal Survey.

Science.gov (United States)

Dockery, A. Michael

This paper uses the Australian Bureau of Statistics' Business Longitudinal Survey to explore relationships between training, innovation, and firm performance for Australian businesses with less than 200 employees. The longitudinal nature of the data is used to test various hypotheses about the nature of the link between training, business changes,…

Prosthetic liner wear in total hip replacement: a longitudinal 13-year study with computed tomography.

Science.gov (United States)

Weidenhielm, Lars; Olivecrona, Henrik; Maguire, Gerald Q; Noz, Marilyn E

2018-06-01

This case report follows a woman who had a total hip replacement in 1992 when she was 45 years old. Six serial computed tomography (CT) examinations over a period of 13 years provided information that allowed her revision surgery to be limited to liner replacement as opposed to replacement of the entire prosthesis. Additionally, they provided data that ruled out the presence of osteolysis and indeed none was found at surgery. In 2004, when the first CT was performed, the 3D distance the femoral head had penetrated into the cup was determined to be 2.6 mm. By 2017, femoral head penetration had progressed to 5.0 mm. The extracted liner showed wear at the thinnest part to be 5.5 mm, as measured with a micrometer. The use of modern CT techniques can identify problems, while still correctable without major surgery. Furthermore, the ability of CT to assess the direction of wear revealed that the liner wear changed from the cranial to dorsal direction.

Azimuthal asymmetries in semi-inclusive deep-inelastic hadron muoproduction on longitudinally polarized protons

Energy Technology Data Exchange (ETDEWEB)

Sirtl, Stefan

2016-06-27

In recent years, measuring azimuthal asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) off polarized targets emerged as a powerful tool to investigate the nucleon spin structure, one of the main objectives of the COMPASS physics program. The two-stage COMPASS spectrometer at the CERN SPS is characterized by a large acceptance and a broad kinematic coverage. It makes use of a tertiary longitudinally polarized high-energetic μ{sup +} beam, impinging on a transversely or longitudinally polarized ammonia target. This thesis is dedicated to the analysis of both leading and subleading longitudinal target spin dependent asymmetries arising in the SIDIS cross section of one hadron and hadron pair production. The results provide new insights to the longitudinal spin structure of the nucleon, addressing the role of spin-orbit couplings and quark-gluon correlations in the framework of collinear or transverse momentum dependent factorization.

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

Science.gov (United States)

Calman, Lynn; Brunton, Lisa; Molassiotis, Alex

2013-02-06

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

Longitudinal and transverse structure functions in decaying nearly homogeneous and isotropic turbulence

International Nuclear Information System (INIS)

Ahmad Imtiaz; Lu Zhi-Ming; Liu Yu-Lu

2014-01-01

Streamwise evolution of longitudinal and transverse velocity structure functions in a decaying homogeneous and nearly isotropic turbulence is reported for Reynolds numbers Re λ up to 720. First, two theoretical relations between longitudinal and transverse structure functions are examined in the light of recently derived relations and the results show that the low-order transverse structure functions can be well approximated by longitudinal ones within the sub-inertial range. Reconstruction of fourth-order transverse structure functions with a recently proposed relation by Grauer et al. is comparatively less valid than the relation already proposed by Antonia et al. Secondly, extended self-similarity methods are used to measure the scaling exponents up to order eight and the streamwise evolution of scaling exponents is explored. The scaling exponents of longitudinal structure functions are, at first location, close to Zybin's model, and at the fourth location, close to She—Leveque model. No obvious trend is found for the streamwise evolution of longitudinal scaling exponents, whereas, on the contrary, transverse scaling exponents become slightly smaller with the development of a steamwise direction. Finally, the stremwise variation of the order-dependent isotropy ratio indicates the turbulence at the last location is closer to isotropic than the other three locations. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Burnout development among dentists : a longitudinal study

NARCIS (Netherlands)

te Brake, H.; Smits, N.; Wicherts, J.M.; Gorter, R.C.; Hoogstraten, J.

2008-01-01

Knowledge on the development of burnout among dentists is important for purposes of prevention and intervention. Using a two-wave longitudinal design, this study examined the chronological sequence of the three dimensions of the Maslach Burnout Inventory: emotional exhaustion; depersonalization; and

A Pluralistic, Longitudinal Method

DEFF Research Database (Denmark)

Evers, Winie; Marroun, Sana; Young, Louise

2017-01-01

There is recognition in business markets of the need for connected relationships to enable the survival and growth of firms. Finding new ways to collaborate enables firms to better seek opportunities and challenges and enhance network capability. However the traditional methods used to research...... and analysis. Longitudinal research considers a Danish advertising and communication firm looking for new ideas by involving their network in order to help them to compete in their environment of rapid globalization and emergence of new technologies. A five stage research design considered how network...

Effect of longitudinal vibration of fluid-filled pipe with elastic wall on sound transmission character

Directory of Open Access Journals (Sweden)

DONG Peng

2017-01-01

Full Text Available When one end of a fluid-filled pipe with an elastic wall is fixed and a harmonic force effect acts on the other end,a steady longitudinal vibration will be produced. Compared to the pipeline resonance mode,the amplitude of the steady longitudinal vibration of an elastic pipe is greater,and the effect on the sound is also greater. The study of the steady longitudinal vibration of pipes can better describe the effects of fluid-filled pipelines on the radiation sound field of the pipe opening. Through the contrast between the analysis calculation of the equivalent beam model and the experimental results,the accuracy of the equivalent beam model for the calculation of the steady longitudinal vibration of pipelines is verified,and a method of isolating the steady longitudinal vibration state is proposed and verified.

Efficient and robust estimation for longitudinal mixed models for binary data

DEFF Research Database (Denmark)

Holst, René

2009-01-01

This paper proposes a longitudinal mixed model for binary data. The model extends the classical Poisson trick, in which a binomial regression is fitted by switching to a Poisson framework. A recent estimating equations method for generalized linear longitudinal mixed models, called GEEP, is used...... as a vehicle for fitting the conditional Poisson regressions, given a latent process of serial correlated Tweedie variables. The regression parameters are estimated using a quasi-score method, whereas the dispersion and correlation parameters are estimated by use of bias-corrected Pearson-type estimating...... equations, using second moments only. Random effects are predicted by BLUPs. The method provides a computationally efficient and robust approach to the estimation of longitudinal clustered binary data and accommodates linear and non-linear models. A simulation study is used for validation and finally...

Longitudinal Analysis of Personal and Work-Related Factors Associated With Turnover Among Nurses

NARCIS (Netherlands)

Estryn-Behar, Madeleine; van der Heijden, Beatrice; Fry, Clementine; Hasselhorn, Hans Martin

2010-01-01

AB Background: Although many scholars have acknowledged the relationship between personal and work-related factors associated with job search and actual turnover, there is a lack of longitudinal designs that test this relationship empirically. Objectives: This longitudinal study examines specific

Second- to Third-Trimester Longitudinal Growth Assessment for the Prediction of Largeness for Gestational Age and Macrosomia in an Unselected Population.

Science.gov (United States)

Caradeux, Javier; Eixarch, Elisenda; Mazarico, Edurne; Basuki, Tri Rahmat; Gratacós, Eduard; Figueras, Francesc

2018-01-01

Prenatal detection of excessive growth remains inaccurate. Most strategies rely on a single cross-sectional evaluation of fetal size during the third trimester. To compare second- to third-trimester longitudinal growth assessment with cross-sectional evaluation at the third trimester in the prediction of largeness for gestational age (LGA) and macrosomia. A cohort of 2,696 unselected singleton pregnancies scanned at 21 ± 2 and 32 ± 2 weeks was created. Abdominal circumference (AC) measurements were transformed to z values according to the INTERGROWTH-21st standards. Longitudinal growth assessment was performed by calculation of z velocity and conditional growth. Both methods were compared to cross-sectional assessment at 32 ± 2 weeks. Predictive performance for LGA and macrosomia was determined by receiver operating characteristic curve analysis. A total of 188 (7%) newborns qualified for LGA and 182 (6.8%) for macrosomia. The areas under the curve (AUCs) for 32-week AC z score, AC z velocity, and conditional AC were 0.78, 0.61, and 0.55, respectively, for the prediction of LGA, and 0.75, 0.61, and 0.55, respectively, for the prediction of macrosomia. Both AUCs of AC z velocity and conditional AC were significantly lower (p third-trimester longitudinal assessment of fetal growth is inferior to third-trimester cross-sectional evaluation of size in the prediction of LGA and macrosomia. © 2017 S. Karger AG, Basel.

Performance Evaluation of State-of-the-Art Local Feature Detectors and Descriptors in the Context of Longitudinal Registration of Retinal Images.

Science.gov (United States)

Saha, Sajib K; Xiao, Di; Frost, Shaun; Kanagasingam, Yogesan

2018-02-17

In this paper we systematically evaluate the performance of several state-of-the-art local feature detectors and descriptors in the context of longitudinal registration of retinal images. Longitudinal (temporal) registration facilitates to track the changes in the retina that has happened over time. A wide number of local feature detectors and descriptors exist and many of them have already applied for retinal image registration, however, no comparative evaluation has been made so far to analyse their respective performance. In this manuscript we evaluate the performance of the widely known and commonly used detectors such as Harris, SIFT, SURF, BRISK, and bifurcation and cross-over points. As of descriptors SIFT, SURF, ALOHA, BRIEF, BRISK and PIIFD are used. Longitudinal retinal image datasets containing a total of 244 images are used for the experiment. The evaluation reveals some potential findings including more robustness of SURF and SIFT keypoints than the commonly used bifurcation and cross-over points, when detected on the vessels. SIFT keypoints can be detected with a reliability of 59% for without pathology images and 45% for with pathology images. For SURF keypoints these values are respectively 58% and 47%. ALOHA descriptor is best suited to describe SURF keypoints, which ensures an overall matching accuracy, distinguishability of 83%, 93% and 78%, 83% for without pathology and with pathology images respectively.

Longitudinal density monitor for the LHC

Directory of Open Access Journals (Sweden)

A. Jeff

2012-03-01

Full Text Available The longitudinal density monitor (LDM is primarily intended for the measurement of the particle population in nominally empty rf buckets. These so-called satellite or ghost bunches can cause problems for machine protection as well as influencing the luminosity calibration of the LHC. The high dynamic range of the system allows measurement of ghost bunches with as little as 0.01% of the main bunch population at the same time as characterization of the main bunches. The LDM is a single-photon counting system using visible synchrotron light. The photon detector is a silicon avalanche photodiode operated in Geiger mode, which allows the longitudinal distribution of the LHC beams to be measured with a resolution of 90 ps. Results from the LDM are presented, including a proposed method for constructing a 3-dimensional beam density map by scanning the LDM sensor in the transverse plane. In addition, we present a scheme to improve the sensitivity of the system by using an optical switching technique.

Longitudinal Survey of Carotenoids in Human Milk from Urban Cohorts in China, Mexico, and the USA.

Directory of Open Access Journals (Sweden)

Tristan E Lipkie

Full Text Available Emerging evidence indicates that carotenoids may have particular roles in infant nutrition and development, yet data on the profile and bioavailability of carotenoids from human milk remain sparse. Milk was longitudinally collected at 2, 4, 13, and 26 weeks postpartum from twenty mothers each in China, Mexico, and the USA in the Global Exploration of Human Milk Study (n = 60 donors, n = 240 samples. Maternal and neonatal plasma was analyzed for carotenoids from the USA cohort at 4 weeks postpartum. Carotenoids were analyzed by HPLC and total lipids by Creamatocrit. Across all countries and lactation stages, the top four carotenoids were lutein (median 114.4 nmol/L, β-carotene (49.4 nmol/L, β-cryptoxanthin (33.8 nmol/L, and lycopene (33.7 nmol/L. Non-provitamin A carotenoids (nmol/L and total lipids (g/L decreased (p0.05 with lactation stage. Total carotenoid content and lutein content were greatest from China, yet lycopene was lowest from China (p0.3. This enhanced understanding of neonatal exposure to carotenoids during development may help guide dietary recommendations and design of human milk mimetics.

Longitudinal Diagnostics for Short Electron Beam Bunches

Energy Technology Data Exchange (ETDEWEB)

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

Generation of longitudinally polarized terahertz pulses with field amplitudes exceeding 2 kV/cm

Science.gov (United States)

Cliffe, M. J.; Rodak, A.; Graham, D. M.; Jamison, S. P.

2014-11-01

We demonstrate the generation of near-single cycle longitudinally polarized terahertz radiation using a large-area radially biased photoconductive antenna with a longitudinal field amplitude in excess of 2 kV/cm. The 76 mm diameter antenna was photo-excited by a 0.5 mJ amplified near-infrared femtosecond laser system and biased with a voltage of up to 100 kV applied over concentric electrodes. Amplitudes for both the transverse and longitudinal field components of the source were measured using a calibrated electro-optic detection scheme. By tightly focusing the radiation emitted from the photoconductive antenna, we obtained a maximum longitudinal field amplitude of 2.22 kV/cm with an applied bias field of 38.5 kV/cm.

Theory of mind in emerging reading comprehension: A longitudinal study of early indirect and direct effects.

Science.gov (United States)

Atkinson, Lynette; Slade, Lance; Powell, Daisy; Levy, Joseph P

2017-12-01

The relation between children's theory of mind (ToM) and emerging reading comprehension was investigated in a longitudinal study over 2.5years. A total of 80 children were tested for ToM, decoding, language skills, and executive function (EF) at Time 1 (mean age=3;10 [years;months]). At Time 2 (mean age=6;03), children's word reading efficiency, language skills, and reading comprehension were measured. Mediation analysis showed that ToM at Time 1, when children were around 4years old, indirectly predicted Time 2 reading comprehension, when children were 6years old, via language ability after controlling for age, nonverbal ability, decoding, EF, and earlier language ability. Importantly, ToM at 4years also directly predicted reading comprehension 2.5years later at 6years. This is the first longitudinal study to show a direct contribution of ToM to reading comprehension in typical development. Findings are discussed in terms of the simple view of reading (SVR); ToM not only supports reading comprehension indirectly by facilitating language but also contributes to it directly over and above the SVR. The potential role of metacognition is considered when accounting for the direct contribution of early ToM to later reading comprehension. Copyright © 2017 Elsevier Inc. All rights reserved.

Rare stress fracture: longitudinal fracture of the femur.

Science.gov (United States)

Pérez González, M; Velázquez Fragua, P; López Miralles, E; Abad Moretón, M M

42-year-old man with pain in the posterolateral region of the right knee that began while he was running. Initially, it was diagnosed by magnetic resonance (MR) as a possible aggressive process (osteosarcoma or Ewing's sarcoma) but with computed tomography it was noted a cortical hypodense linear longitudinal image with a continuous, homogeneous and solid periosteal reaction without clear soft tissue mass that in this patient suggest a longitudinal distal femoral fatigue stress fracture. This type of fracture at this location is very rare. Stress fractures are entities that can be confused with an agressive process. MR iscurrently the most sensitive and specific imaging method for its diagnosis. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Distribution of Total Suspended Solids Concentration in a River

Directory of Open Access Journals (Sweden)

Ahmad Hanif Asyhar

2012-08-01

Full Text Available Disposal of either industrial or nonindustrial wastewater into a river has a potential to cause riverpollution. Because each load of wastewater discharged into a river contains physical, chemical, and biological parametersthat determine water quality, so that it can affect the dissolved oxygen concentration in a river. Therefore the conductedresearch was aimed to determine the pattern of pollutant dispersion in Surabaya River within the section that is closed tothe Karang Pilang Monitoring Station - Surabaya. Parameter used in this research was Total Suspended Solids (TSS. Themethod used was the finite volume method with Quadratic Upwind Interpolation Convective Kinematics (QUICK schemeby means of developing models of dispersion water pollutants in a river. The governing equation was controlled by the lawsof mass conservation, momentum conservation, and pollution transport equation. Further, these equations were solvedusing numerical calculation and followed by numerical simulation. From the numerical simulation results, it can beconcluded that the magnitude of pollutant dispersion is determined by the initial discharged TSS concentrations into theriver, however the longitudinal direction is more dominantly influenced than in lateral directions.

A longitudinal evaluation of persons with disabilities: does a longitudinal definition help define who receives necessary care?

Science.gov (United States)

Chan, Leighton; Ciol, Marcia A; Shumway-Cook, Anne; Yorkston, Kathryn M; Dudgeon, Brian J; Asch, Steven M; Hoffman, Jeanne M

2008-06-01

To assess, using a longitudinal definition, the impact of disability on a broad range of objective health care quality indicators. Longitudinal cohort study following up with patients over several years. The first 2 interviews, 1 year apart, were used to determine each patient's disability status in activities of daily living (ADLs). Assessment of the health care indicators commenced after the second interview and continued throughout the survey period (an additional 1-3y). National survey. Participants (N=29,074) of the Medicare Current Beneficiary Survey (1992-2001) with no, increasing, decreasing, and stable ADL disability. Not applicable. The incidence of 5 avoidable outcomes, receipt of 3 preventive care measures, and adherence to 32 diagnostically based indicators assessing the quality of treatment for acute myocardial infarction [AMI], angina, breast cancer, cerebrovascular accident, transient ischemic attack, cholelithiasis, chronic obstructive pulmonary disease [COPD], congestive heart failure, depression, gastrointestinal bleeding, diabetes, and hypertension. For most indicators, less than 75% of eligible patients received necessary care, regardless of disability status. For 5 indicators, less than 50% of patients received appropriate treatment. In a logistic regression analysis that controlled for patient age, sex, race, and income, disability status was a significant factor in 7 quality measures (AMI, breast cancer, COPD, diabetes, angina, pneumonia, annual visits). Using a longitudinal definition of disability and objective health quality indicators, we found that disability status can be an important factor in determining receipt of quality health care in a broad range of diagnostic categories. However, the impact of disability status varies depending on the indicator measured. In this cohort of patients, the changing nature of a person's disability seems to have less impact than whether they ever have had any functional deficits.

Incidence, risk factors and the healthcare cost of falls postdischarge after elective total hip and total knee replacement surgery: protocol for a prospective observational cohort study

Science.gov (United States)

Hill, Anne-Marie; Ross-Adjie, Gail; McPhail, Steven M; Monterosso, Leanne; Bulsara, Max; Etherton-Beer, Christopher; Powell, Sarah-Jayne; Hardisty, Gerard

2016-01-01

Introduction The number of major joint replacement procedures continues to increase in Australia. The primary aim of this study is to determine the incidence of falls in the first 12 months after discharge from hospital in a cohort of older patients who undergo elective total hip or total knee replacement. Methods and analyses A prospective longitudinal observational cohort study starting in July 2015, enrolling patients aged ≥60 years who are admitted for elective major joint replacement (n=267 total hip replacement, n=267 total knee replacement) and are to be discharged to the community. Participants are followed up for 12 months after hospital discharge. The primary outcome measure is the rate of falls per thousand patient-days. Falls data will be collected by 2 methods: issuing a falls diary to each participant and telephoning participants monthly after discharge. Secondary outcomes include the rate of injurious falls and health-related quality of life. Patient-rated outcomes will be measured using the Oxford Hip or Oxford Knee score. Generalised linear mixed modelling will be used to examine the falls outcomes in the 12 months after discharge and to examine patient and clinical characteristics predictive of falls. An economic evaluation will be conducted to describe the nature of healthcare costs in the first 12 months after elective joint replacement and estimate costs directly attributable to fall events. Ethics and dissemination The results will be disseminated through local site networks and will inform future services to support older people undergoing hip or knee joint replacement and also through peer-reviewed publications and medical conferences. This study has been approved by The University of Notre Dame Australia and local hospital human research ethics committees. Trial registration number ACTRN12615000653561; Pre-results. PMID:27412102

The Latent Curve ARMA (P, Q) Panel Model: Longitudinal Data Analysis in Educational Research and Evaluation

Science.gov (United States)

Sivo, Stephen; Fan, Xitao

2008-01-01

Autocorrelated residuals in longitudinal data are widely reported as common to longitudinal data. Yet few, if any, researchers modeling growth processes evaluate a priori whether their data have this feature. Sivo, Fan, and Witta (2005) found that not modeling autocorrelated residuals present in longitudinal data severely biases latent curve…

The impact of extended longitudinal observation on the assessment of personality disorders.

Science.gov (United States)

Pedersen, G; Karterud, S; Hummelen, B; Wilberg, T

2013-11-01

Multiple sources of information are necessary for a valid assessment of personality disorders (PDs). This study investigates the impact of longitudinal observation. The sample comprised 1217 patients from 15 different treatment units. PDs were assessed at admission to treatment using the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II) and additional clinical information (best estimate diagnosis). After approximately 18 weeks of treatment, the SCID-II protocols were re-examined at clinical conferences and the diagnostic status reassessed on the basis of longitudinal observations in multiple group situations (longitudinal, expert, all data principle). Using this procedure, 78% of the patients' diagnostic criteria sets were changed, and 32% of patients' diagnostic statuses were changed. Many (32%) patients who were evaluated initially as not having a PD received a PD diagnosis after re-examination. The information provided by customary clinical assessment has important limitations, and longitudinal observation provides additional information that may change the diagnostic status in approximately one-third of PD cases. Copyright © 2013 John Wiley & Sons, Ltd.

Effect of total laryngectomy on esophageal motility

International Nuclear Information System (INIS)

Hanks, J.B.; Fisher, S.R.; Meyers, W.C.; Christian, K.C.; Postlethwait, R.W.; Jones, R.S.

1981-01-01

Total laryngectomy for cancer can result in dysphagia and altered esophageal motility. Manometric changes in the upper esophageal sphincter (UES), and in proximal and distal esophageal function have been reported. However, most studies have failed to take into account radiation therapy and appropriate controls. We selected ten male patients (54.3 +/- 1.9 yr) for longitudinal manometric evaluation prior to laryngectomy then at two weeks and again six months later. No patient received preoperative radiation therapy, had a previous history of esophageal surgery, or developed a postoperative wound infection or fistula. Seven of ten patients had positive nodes and received 6,000-6,600 rads postoperative radiation therapy. Preoperatively 4 of 10 patients complained of dysphagia which did not significantly change following surgery and radiation. Two of three patients who did not complain of dysphagia preoperatively and received radiation postoperatively developed dysphagia. No patient without dysphagia preoperatively who received no radiation therapy developed symptoms. Our studies show that laryngectomy causes alterations in the UES resting and peak pressures but not in the proximal or distal esophagus, or the lower esophageal sphincter. These data also imply radiation therapy may be associated with progressive alterations in motility and symptomatology. Further study regarding the effects of radiation on esophageal motility and function are urged

Longitudinal phase-space matching between microtrons at 185 MeV

International Nuclear Information System (INIS)

Takeda, H.

1983-01-01

Electrons are accelerated to 185 MeV by a microtron. Then, they are injected into another microtron to boost the net energy up to a few GeV. Between the two microtrons both longitudinal and transverse phase-space matching are required. In this paper, we consider a longitudinal phase-ellipse matching which utilizes triple left-right-left sector dipoles to induce a negative phase-angle shear. This is accomplished because a high-energy particle travels a shorter distance through the dipole system than a low-energy particle

Stability and change in adult personality over 6 years: findings from the Victoria Longitudinal Study.

Science.gov (United States)

Small, Brent J; Hertzog, Christopher; Hultsch, David F; Dixon, Roger A

2003-05-01

Data from the Victoria Longitudinal Study were used to examine the 6-year longitudinal stability of personality in older adults. Personality was measured with the NEO Personality Inventory. The longitudinal sample consisted of 223 adults initially ranging from 55 to 85 years of age. Longitudinal confirmatory factor analyses were used to examine the stability of individual differences in change over time, and the stability of the longitudinal factor structure. The results indicated both substantial stability at the level of individual differences in change, as well as significant individual differences in change that were related to age and gender. Finally, the factor structure of personality was invariant over time but did not approximate simple structure for the five dimensions of personality. Our study of 6-year personality development provided both (a). a confirmation of early significant stability findings and (b). unique evidence for significant individual differences in late adulthood.

Predicting pathologic tumor response to chemoradiotherapy with histogram distances characterizing longitudinal changes in 18F-FDG uptake patterns

Science.gov (United States)

Tan, Shan; Zhang, Hao; Zhang, Yongxue; Chen, Wengen; D’Souza, Warren D.; Lu, Wei

2013-01-01

Purpose: A family of fluorine-18 (18F)-fluorodeoxyglucose (18F-FDG) positron-emission tomography (PET) features based on histogram distances is proposed for predicting pathologic tumor response to neoadjuvant chemoradiotherapy (CRT). These features describe the longitudinal change of FDG uptake distribution within a tumor. Methods: Twenty patients with esophageal cancer treated with CRT plus surgery were included in this study. All patients underwent PET/CT scans before (pre-) and after (post-) CRT. The two scans were first rigidly registered, and the original tumor sites were then manually delineated on the pre-PET/CT by an experienced nuclear medicine physician. Two histograms representing the FDG uptake distribution were extracted from the pre- and the registered post-PET images, respectively, both within the delineated tumor. Distances between the two histograms quantify longitudinal changes in FDG uptake distribution resulting from CRT, and thus are potential predictors of tumor response. A total of 19 histogram distances were examined and compared to both traditional PET response measures and Haralick texture features. Receiver operating characteristic analyses and Mann-Whitney U test were performed to assess their predictive ability. Results: Among all tested histogram distances, seven bin-to-bin and seven crossbin distances outperformed traditional PET response measures using maximum standardized uptake value (AUC = 0.70) or total lesion glycolysis (AUC = 0.80). The seven bin-to-bin distances were: L2 distance (AUC = 0.84), χ2 distance (AUC = 0.83), intersection distance (AUC = 0.82), cosine distance (AUC = 0.83), squared Euclidean distance (AUC = 0.83), L1 distance (AUC = 0.82), and Jeffrey distance (AUC = 0.82). The seven crossbin distances were: quadratic-chi distance (AUC = 0.89), earth mover distance (AUC = 0.86), fast earth mover distance (AUC = 0.86), diffusion distance (AUC = 0.88), Kolmogorov-Smirnov distance (AUC = 0.88), quadratic form distance

Exposure to polychlorinated biphenyls and the thyroid gland – examining and discussing possible longitudinal health effects in humans

Energy Technology Data Exchange (ETDEWEB)

Gaum, Petra M., E-mail: pgaum@ukaachen.de [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Lang, Jessica; Esser, André; Schettgen, Thomas [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Neulen, Joseph [Clinic for Gynaecological Endocrinology and Reproductive Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany); Kraus, Thomas; Gube, Monika [Institute for Occupational and Social Medicine, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen (Germany)

2016-07-15

Background: Many previous studies have dealt with the effect of polychlorinated biphenyls (PCBs) on the thyroid gland, but their findings are inconsistent. One problem of these studies has been their use of cross-sectional designs. Objectives: The aim of the current study is to investigate longitudinal effects of PCBs on the thyroid gland, focusing on: morphological changes in thyroid tissue (i.e. thyroid volume), changes in thyroid hormones and in thyroid antibodies. Methods: A total of 122 individuals (M{sub age}=44.7) were examined over a period of four years (t{sup 1} until t{sup 4}). Medical history was collected via interviews, an ultrasound examination was performed and blood samples were taken to determine plasma PCB levels, thyroid stimulating hormone (TSH), free triiodthyronine (fT3), free thyroxine (fT4), thyroid peroxidase antibodies (TPOab), thyreoglobulin antibodies (TGab) and thyroid-stimulating hormone receptor antibodies (TSHRab). Rank correlation coefficients and mixed effect models were performed controlling for age and total lipids. Results: There were negative correlations between higher chlorinated biphenyls and fT3, cross-sectionally as well as longitudinally. We also found an interaction effect of higher-chlorinated PCBs over time for fT4 as well as TSHRab. In case of high exposure, a decrease in fT4 and an increase in TSHRab level were found over time. In regards to the other variables, our findings yielded no clear results in the examined time period. Conclusion: This is the first study to shows a PCB-related effect on fT3, fT4 and TSHRab over a four year period. The data also suggest that morphological and antibody findings remain inconsistent and do not allow for unambiguous interpretation. - Highlights: • This is a longitudinal study which includes data from four cross sections. • Higher-chlorinated biphenyls are negatively correlated with fT3. • There are interactions of time and higher-chlorinated biphenyls to TSHRab and fT4. �

Estudo longitudinal das habilidades intelectuais de idosos avaliados com a WAIS-III Longitudinal study of intellectual abilities of elderly people assessed by WAIS-III

Directory of Open Access Journals (Sweden)

Ana Carolina Zeferino Menezes

2011-01-01

Full Text Available Dados indicam que o envelhecimento, ainda que saudável, acarreta um declínio normal no desempenho intelectual. O presente estudo teve por objetivo investigar o desenvolvimento intelectual de idosos em diferentes domínios avaliados pela WAIS-III. A partir de um delineamento longitudinal, 47 participantes foram divididos em duas faixas etárias: idosos-jovens (até 74 anos e idosos-idosos (acima de 75 anos e seus desempenhos foram comparados após oito anos de intervalo. Resultados mostraram que idosos-jovens apresentaram ganhos nas habilidades avaliadas, embora em apenas dois índices estes tenham sido estatisticamente significativos. Com relação às capacidades de compreensão verbal e linguagem, os ganhos eram esperados. Já Memória, Organização Perceptual, Velocidade de Processamento, QI de Execução e Total não se comportaram como grande parte dos estudos reporta. Resultados para os idosos-idosos estão de acordo com a literatura: habilidades vulneráveis (organização perceptual, aprendizagem, memória, resolução de problemas e velocidade de processamento tiveram decréscimos após os oito anos entre as avaliações. Embora nem todos os resultados tenham sido significativos, corroboram dados de pesquisas que definem a idade de declínios significativos após os 75 anos. Concluindo, os resultados indicaram que os idosos não apresentaram declínio nas habilidades intelectuais avaliadas até a idade de 74 anos, a partir de quando alguma perda foi encontrada. A velocidade de processamento foi a única habilidade que apresentou declínio significativo. Portanto, as variações nos desempenhos não caracterizam um padrão de declínio generalizado, ou seja, não ocorrem em todas as habilidades e variam conforme a idade.Data have indicated that aging, even if in a healthy process, lead to a normal decrease in cognitive performance. The current study aims at investigating the intellectual development of elderly people in different

Longitudinal gradient in limnological variables in the Upper Paraná River: a brief description and the importance of undammed tributaries

Directory of Open Access Journals (Sweden)

Natália Fernanda Santana

2017-12-01

Full Text Available Abstract Aim: Describe the limnological pattern in a longitudinal gradient in the Paraná River, a highly dammed river, in a stretch localized between two dams, but rich in undammed tributaries. Methods Twelve transects in the longitudinal gradient of the Paraná River were sampled, with the first transect being placed right after Porto Primavera dam, and the last one in the lotic region of the Itaipu dam. In each of these transects, water transparency, electrical conductivity, pH, total nitrogen and total phosphorous were analyzed. Results In those regions nearer Porto Primavera dam it was observed high values of water transparency and low values of nitrogen and phosphorous. The values of water transparency decreased and the values of nitrogen and phosphorous increased as the distance from Porto Primavera dam increased. Because the new tributaries connect to the Paraná River, with the sites farer from Porto Primavera dam presenting values similar to those prior its construction. Conclusions Increase in the nutrients concentration and changes in ecological integrity are probably due to the presence of the undammed tributaries. They are originate in different river basins and therefore contribute to the Paraná River in distinct manners. Results presented here are an indicative of the fundamental importance of undammed tributaries in mitigating damming negative impacts in extremely dammed rivers and highlight the importance of keeping such tributaries free of dams.

Role of the ambient magnetic field B in the longitudinal variation of ...

African Journals Online (AJOL)

Comparison of the longitudinal profile of B along the dip equator with average longitudinal profile of the zonal electric field Ey at the dip equator proves that on the average Ey is not independent of longitude as was assumed by earlier workers. It has been suggested that Joule heating of the atmosphere which depends on ...

Tailored Panel Management: A Theory-Based Approach to Building and Maintaining Participant Commitment to a Longitudinal Study.

Science.gov (United States)

Estrada, Mica; Woodcock, Anna; Schultz, P Wesley

2014-02-01

Many psychological processes unfold over time, necessitating longitudinal research designs. Longitudinal research poses a host of methodological challenges, foremost of which is participant attrition. Building on Dillman's work, we provide a review of how social influence and relationship research informs retention strategies in longitudinal studies. Objective: We introduce the tailored panel management (TPM) approach, which is designed to establish communal norms that increase commitment to a longitudinal study, and this commitment, in turn, increases response rates and buffers against attrition. Specifically, we discuss practices regarding compensation, communication, consistency, and credibility that increase longer term commitment to panel participation. Research design: Throughout the article, we describe how TPM is being used in a national longitudinal study of undergraduate minority science students. TheScienceStudy is a continuing panel, which has 12 waves of data collected across 6 academic years, with response rates ranging from 70% to 92%. Although more than 90% of participants have either left or graduated from their undergraduate degree program, this highly mobile group of people remains engaged in the study. TheScienceStudy has usable longitudinal data from 96% of the original panel. Conclusion: This article combines social psychological theory, current best practice, and a detailed case study to illustrate the TPM approach to longitudinal data collection. The approach provides guidance for other longitudinal researchers, and advocates for empirical research into longitudinal research methodologies. © The Author(s) 2014.

The Longitudinal Joint Effect of Obesity and Major Depression on Work Performance Impairment

NARCIS (Netherlands)

Nigatu, Yeshambel T.; Reijneveld, Sijmen A.; Penninx, Brenda W. J. H.; Schoevers, Robert A.; Bultmann, Ute

Objectives. We examined the longitudinal effect of obesity, major depression, and their combination on work performance impairment (WPI). Methods. We collected longitudinal data (2004-2013) on 1726 paid employees from the Netherlands Study of Depression and Anxiety at baseline and 2-, 4-, and 6-year

The longitudinal joint effect of obesity and major depression on work performance impairment

NARCIS (Netherlands)

Nigatu, Y.T.; Reijneveld, S.A.; Penninx, B.W.; Schoevers, R.A.; Bultmann, U.

2015-01-01

Objectives: We examined the longitudinal effect of obesity, major depression, and their combination on work performance impairment (WPI). Methods: We collected longitudinal data (2004-2013) on 1726 paid employees from the Netherlands Study of Depression and Anxiety at baseline and 2-, 4-, and 6-year

Serum Calcium and the Risk of Incident Metabolic Syndrome: A 4.3-Year Retrospective Longitudinal Study

Directory of Open Access Journals (Sweden)

Jong Ha Baek

2017-01-01

Full Text Available BackgroundAn association between serum calcium level and risk of metabolic syndrome (MetS has been suggested in cross-sectional studies. This study aimed to evaluate the association between baseline serum calcium level and risk of incident MetS in a longitudinal study.MethodsWe conducted a retrospective longitudinal study of 12,706 participants without MetS who participated in a health screening program, had normal range serum calcium level at baseline (mean age, 51 years, and were followed up for 4.3 years (18,925 person-years. The risk of developing MetS was analyzed according to the baseline serum calcium levels.ResultsA total of 3,448 incident cases (27.1% of MetS developed during the follow-up period. The hazard ratio (HR for incident MetS did not increase with increasing tertile of serum calcium level in an age- and sex-matched model (P for trend=0.915. The HRs (95% confidence interval [CI] for incident MetS comparing the second and the third tertiles to the first tertile of baseline serum calcium level were 0.91 (95% CI, 0.84 to 0.99 and 0.85 (95% CI, 0.78 to 0.92 in a fully adjusted model, respectively (P for trend=0.001. A decreased risk of incident MetS in higher tertiles of serum calcium level was observed in subjects with central obesity and/or a metabolically unhealthy state at baseline.ConclusionThere was no positive correlation between baseline serum calcium levels and incident risk of MetS in this longitudinal study. There was an association between higher serum calcium levels and decreased incident MetS in individuals with central obesity or two components of MetS at baseline.

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

Science.gov (United States)

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

2018-02-01

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

Advection models of longitudinal dispersion in rivers

NARCIS (Netherlands)

Kranenburg, C.

1996-01-01

A derivation is presented of a general cross-section averaged model of longitudinal dispersion, which is based on the notion of the advection of tracer particles. Particle displacement length and particle travel time are conceived as stochastic variables, and a joint probability density function is

Vertical and longitudinal electron density structures of equatorial E- and F-regions

Directory of Open Access Journals (Sweden)

P. S. Brahmanandam

2011-01-01

Full Text Available From global soundings of ionospheric electron density made with FORMOSAT 3/COSMIC satellites for September 2006–August 2009, day-night variations in vertical and longitudinal structures of the electron densities in equatorial E- and F-regions for different seasons are investigated for the first time. The results reveal that the wavenumber-3 and wavenumber-4 patterns dominated the nighttime (22:00–04:00 LT F-region longitudinal structures in solstice and in equinox seasons, respectively. In daytime (08:00–18:00 LT F-region, the wavenumber-4 patterns governed the longitudinal structures in the September equinox and December solstice, and wavenumber-3 in March equinox and June solstice respectively. A comparison of the daytime and nighttime longitudinal electron density structures indicates that they are approximately 180° out of phase with each other. It is believed that this out of phase relation is very likely the result of the opposite phase relation between daytime and nighttime nonmigrating diurnal tidal winds that modulate background E-region dynamo electric field at different places, leading to the day-night change in the locations of the equatorial plasma fountains that are responsible for the formation of the F-region longitudinal structures. Further, a good consistency between the locations of the density structures in the same seasons of the different years for both daytime and nighttime epochs has been noticed indicating that the source mechanism for these structures could be the same.

Generalized empirical likelihood methods for analyzing longitudinal data

KAUST Repository

Wang, S.; Qian, L.; Carroll, R. J.

2010-01-01

Efficient estimation of parameters is a major objective in analyzing longitudinal data. We propose two generalized empirical likelihood based methods that take into consideration within-subject correlations. A nonparametric version of the Wilks

A longitudinal study of lexical development in children learning Vietnamese and English.

Science.gov (United States)

Pham, Giang; Kohnert, Kathryn

2014-01-01

This longitudinal study modeled lexical development among children who spoke Vietnamese as a first language (L1) and English as a second language (L2). Participants (n = 33, initial mean age of 7.3 years) completed a total of eight tasks (four in each language) that measured vocabulary knowledge and lexical processing at four yearly time points. Multivariate hierarchical linear modeling was used to calculate L1 and L2 trajectories within the same model for each task. Main findings included (a) positive growth in each language, (b) greater gains in English resulting in shifts toward L2 dominance, and (c) different patterns for receptive and expressive domains. Timing of shifts to L2 dominance underscored L1 skills that are resilient and vulnerable to increases in L2 proficiency. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

Tea Consumption Reduces the Incidence of Neurocognitive Disorders: Findings from the Singapore Longitudinal Aging Study.

Science.gov (United States)

Feng, L; Chong, M-S; Lim, W-S; Gao, Q; Nyunt, M S; Lee, T-S; Collinson, S L; Tsoi, T; Kua, E-H; Ng, T-P

2016-01-01

To examine the relationships between tea consumption habits and incident neurocognitive disorders (NCD) and explore potential effect modification by gender and the apolipoprotein E (APOE) genotype. Population-based longitudinal study. The Singapore Longitudinal Aging Study (SLAS). 957 community-living Chinese elderly who were cognitively intact at baseline. We collected tea consumption information at baseline from 2003 to 2005 and ascertained incident cases of neurocognitive disorders (NCD) from 2006 to 2010. Odds ratio (OR) of association were calculated in logistic regression models that adjusted for potential confounders. A total of 72 incident NCD cases were identified from the cohort. Tea intake was associated with lower risk of incident NCD, independent of other risk factors. Reduced NCD risk was observed for both green tea (OR=0.43) and black/oolong tea (OR=0.53) and appeared to be influenced by the changing of tea consumption habit at follow-up. Using consistent non-tea consumers as the reference, only consistent tea consumers had reduced risk of NCD (OR=0.39). Stratified analyses indicated that tea consumption was associated with reduced risk of NCD among females (OR=0.32) and APOE ε4 carriers (OR=0.14) but not males and non APOE ε4 carriers. Regular tea consumption was associated with lower risk of neurocognitive disorders among Chinese elderly. Gender and genetic factors could possibly modulate this association.

Ecstasy use and depression: a 4-year longitudinal study among an Australian general community sample.

Science.gov (United States)

George, Amanda M; Olesen, Sarah; Tait, Robert J

2013-10-01

Longitudinal, population-based studies can better assess the relationship of ecstasy use with depression. We examined whether change in ecstasy use was associated with change in depressive symptoms/probable depression over a 4-year period, among a large Australian sample. The Personality and Total Health project is a longitudinal general community study of Australians from Canberra and Queanbeyan. Data from the youngest cohort when aged 24-30 (N = 2, 128) and 4 years later (N = 1, 977) was included. The Goldberg depression scale and the Brief Patient Health Questionnaire measured depressive symptoms and probable depression, respectively. Multilevel growth models also considered demographics, psychosocial characteristics, and other drug use. Ecstasy use was not associated with long-term depressive symptoms or greater odds of depression in multivariate analyses. Users had more self-reported depressive symptoms when using ecstasy compared to not using. However, differences between people who had and had not ever used ecstasy largely accounted for this. Other factors were more important in the prediction of depression. It would be premature to conclude that ecstasy use is not related to the development of long-term depressive symptoms, given the relatively low level of ecstasy and other drug use in this community sample. Results showed that other factors need to be considered when investigating ecstasy use and depression.

Closed-form expressions for flip angle variation that maximize total signal in T1-weighted rapid gradient echo MRI.

Science.gov (United States)

Drobnitzky, Matthias; Klose, Uwe

2017-03-01

Magnetization-prepared rapid gradient-echo (MPRAGE) sequences are commonly employed for T1-weighted structural brain imaging. Following a contrast preparation radiofrequency (RF) pulse, the data acquisition proceeds under nonequilibrium conditions of the relaxing longitudinal magnetization. Variation of the flip angle can be used to maximize total available signal. Simulated annealing or greedy algorithms have so far been published to numerically solve this problem, with signal-to-noise ratios optimized for clinical imaging scenarios by adhering to a predefined shape of the signal evolution. We propose an unconstrained optimization of the MPRAGE experiment that employs techniques from resource allocation theory. A new dynamic programming solution is introduced that yields closed-form expressions for optimal flip angle variation. Flip angle series are proposed that maximize total transverse magnetization (Mxy) for a range of physiologic T1 values. A 3D MPRAGE sequence is modified to allow for a controlled variation of the excitation angle. Experiments employing a T1 contrast phantom are performed at 3T. 1D acquisitions without phase encoding permit measurement of the temporal development of Mxy. Image mean signal and standard deviation for reference flip angle trains are compared in 2D measurements. Signal profiles at sharp phantom edges are acquired to access image blurring related to nonuniform Mxy development. A novel closed-form expression for flip angle variation is found that constitutes the optimal policy to reach maximum total signal. It numerically equals previously published results of other authors when evaluated under their simplifying assumptions. Longitudinal magnetization (Mz) is exhaustively used without causing abrupt changes in the measured MR signal, which is a prerequisite for artifact free images. Phantom experiments at 3T verify the expected benefit for total accumulated k-space signal when compared with published flip angle series. Describing

Longitudinal vortex control - Techniques and applications (The 32nd Lanchester Lecture)

Science.gov (United States)

Bushnell, D. M.

1992-01-01

A summary is presented of vortex control applications and current techniques for the control of longitudinal vortices produced by bodies, leading edges, tips and intersections. Vortex control has up till now been performed by many approaches in an empirical fashion, assisted by the essentially inviscid nature of much of longitudinal vortex behavior. Attention is given to Reynolds number sensitivities, vortex breakdown and interactions, vortex control on highly swept wings, and vortex control in juncture flows.

Process of magnetic reconnection as a source of longitudinal currents

International Nuclear Information System (INIS)

Sidneva, M.V.; Semenov, V.S.

1987-01-01

Variations in magnetic field and current system as applied to conditions in the Earth magnetospheric tail are calculated so as to show that three-dimensional reconnection leads inevitably to the appearance of a system of longitudinal currents. With reference to current layer of the magnetospheric tail the longitudinal currents appearing in the process of reconnection are directed to the Earth on the morning side and from Earth - on the evening side. The results presented suggest that magnetic reconnection can serve as a sourse of the Birkeland current loop of a substorm

Longitudinal Effects of Violent Media Usage on Aggressive Behavior—The Significance of Empathy

Directory of Open Access Journals (Sweden)

Thomas Mößle

2014-02-01

Full Text Available The aim of this study was to thoroughly investigate the link between violent media consumption and aggressive behavior. Using a large longitudinal student sample, the role of empathy as a possible mediator of this relationship was of special interest. Data were drawn from wave three to five of the Berlin Longitudinal Study Media, a four-year longitudinal control group study with 1207 school children. Participants completed measures of media usage (violent content of TV and computer games, aggressive behavior perpetration, and empathy. The average age of participants was 10.4 years at Time 1 and 12.4 years at Time 3. Half of the study sample was male (50%. Trivariate structural equation modeling using three measurement times were conducted for assessing the role of empathy as a mediator of the longitudinal relationship between the usage of violent media content and aggressive behavior. For male students empathic skills were shown to unfold a key mediating role between problematic media usage and aggressive behavior.

Longitudinal effect in the night-time mid-latitude ionosphere according to the Interkosmos-19 data

International Nuclear Information System (INIS)

Deminov, M.G.; Karpachev, A.T.

1988-01-01

Longitudinal effects in the night-time mid-latitude external ionosphere for summer and winter conditions of the high solar activity period are analysed. The high amplitude of longitudinal changes of the external ionosphere, including changes of the height (upto 150 km) and the concentration (7-8 times) of the F2-layer maximum, is shown to be provided under winter mid-night-time conditions with high values of the zone component of the wind velocity and strong latitude gradients and with longitudinal changes of the meridional projection of the wind velocity. N changes with the longitude before the Sun setting, when the zone component of the wind velocity is maximum, made the main contribution in summer to longitudinal changes of the electron concentration of the N night ionosphere. The wind velocity phase shift during the season lleads to the fact that the maximum amplitude of N longitudinal changes is observed till midnight in summer and after midnight in winter

Inclusive Deep Inelastic Scattering at High Q2 with Longitudinally Polarised Lepton Beams at HERA

CERN Document Server

Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

2012-01-01

Inclusive e\\pmp single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of \\surds = 319GeV with a total integrated luminosity of 333.7 pb-1 shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative fourmomentum transfer squared, Q2, between 60 and 50 000GeV2, and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF_3^gammaZ. A measurement of the neutral current parity violating structure function F_2^gammaZ is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusi...

Latitudinal and longitudinal variation in aerosol characteristics from ...

Indian Academy of Sciences (India)

The physical and chemical properties of aerosols are strong ... Keywords. Aerosol optical characteristics; latitudinal and longitudinal variations; Bay of Bengal; Arabian Sea; pre- ...... of global sources of atmospheric soil dust identified with the ...

Research on a Novel Exciting Method for a Sandwich Transducer Operating in Longitudinal-Bending Hybrid Modes

Directory of Open Access Journals (Sweden)

Yingxiang Liu

2017-06-01

Full Text Available A novel exciting method for a sandwich type piezoelectric transducer operating in longitudinal-bending hybrid vibration modes is proposed and discussed, in which the piezoelectric elements for the excitations of the longitudinal and bending vibrations share the same axial location, but correspond to different partitions. Whole-piece type piezoelectric plates with three separated partitions are used, in which the center partitions generate the first longitudinal vibration, while the upper and lower partitions produce the second bending vibration. Detailed comparisons between the proposed exciting method and the traditional one were accomplished by finite element method (FEM calculations, which were further verified by experiments. Compared with the traditional exciting method using independent longitudinal ceramics and bending ceramics, the proposed method achieves higher electromechanical coupling factors and larger vibration amplitudes, especially for the bending vibration mode. This novel exciting method for longitudinal-bending hybrid vibrations has not changed the structural dimensions of the sandwich transducer, but markedly improves the mechanical output ability, which makes it very helpful and meaningful in designing new piezoelectric actuators operated in longitudinal-bending hybrid vibration modes.

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

Science.gov (United States)

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

2009-07-01

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

14 CFR 25.173 - Static longitudinal stability.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 25.173... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173 Static... forces (including friction) must be as follows: (a) A pull must be required to obtain and maintain speeds...

Are Sibling Relationships Protective? A Longitudinal Study

Science.gov (United States)

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…

The ONS Longitudinal Study--a prestigious past and a bright future.

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Goldring, Shayla; Newman, Jim

2010-01-01

This issue of Population Trends includes a number of articles and reports resulting from research based on the ONS Longitudinal Study (ONS LS). They have been drawn together in one issue to highlight the value of this type of study for demographic research.2009 marked the 35th anniversary of the establishment of the ONS LS. The study now contains data from the last four censuses (1971 to 2001), linked to vital events data since 1971, for a sample of one per cent of the population of England and Wales.More recently, sister studies have been established in Scotland and Northern Ireland. The Scottish Longitudinal Study (SLS) started with 1991 Census data and the Northern Ireland Longitudinal Study (NILS)started with 2001 Census data.The lead article in this issue comes from an exemplar project that was established to explore how to utilise the three studies to carry out UK-wide longitudinal analysis. Two different methods were used to analyse socio-economic and country level differences in health and mortality across the studies. The article summarises the results of this analysis, reports on the relative strengths of the different methods used, and draws attention to a number of new resources that have been developed by the project researchers as aids to using all three studies.This is an excellent example of collaborative working across the UK, involving researchers from the Centre for Longitudinal Study Information and User Support (CeLSIUS) at the London School of Hygiene and Tropical Medicine, the Longitudinal Studies Centre - Scotland (LSCS) at the University of St.Andrews and the Northern Ireland Longitudinal Study - Research Support Unit (NILS-RSU) at Queen's University Belfast. The project also involved collaboration between ONS, the General Register Office for Scotland (GROS) and the Northern Ireland Statistics and Research Agency (NISRA) to ensure the secure transfer and handling of data from the three studies so that it could be brought together in one

Longitudinal profile monitors using Coherent Smith–Purcell radiation

International Nuclear Information System (INIS)

Andrews, H.L.; Bakkali Taheri, F.; Barros, J.; Bartolini, R.; Cassinari, L.; Clarke, C.; Le Corre, S.; Delerue, N.; Doucas, G.; Fuster-Martinez, N.; Konoplev, I.; Labat, M.; Perry, C.; Reichold, A.; Stevenson, S.; Vieille Grosjean, M.

2014-01-01

Coherent Smith–Purcell radiation has the potential of providing information on the longitudinal profile of an electron bunch. The E-203 experiment at the FACET User Facility measures bunch profiles from the SLAC linac in the hundreds of femtoseconds range and the SPESO collaboration at Synchrotron SOLEIL is planning to make an accurate 2D map of the Coherent Smith–Purcell Radiation emission. - Highlights: • Coherent Smith–Purcell radiation can be used to measure longitudinal profiles in the hundred femtoseconds range. • The current setup used by the E-203 collaboration require integration over several shots and gratings. • Reducing the integration over a single shot and a single grating still yields a meaning full result. • The SPESO experiment at SOLEIL will make a systematic study of Coherent Smith–Purcell radiation

Longitudinal Phase Space Tomography with Space Charge

CERN Document Server

Hancock, S; Lindroos, M

2000-01-01

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 non-linearity 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...

Tomographic Measurements of Longitudinal Phase Space Density

CERN Document Server

Hancock, S; McIntosh, E; Metcalf, M

1999-01-01

Tomography : the reconstruction of a two-dimensional image from a series of its one-dimensional projections is now a very broad topic with a wealth of algorithms for the reconstruction of both qualitative and quantitative images. One of the simplest algorithms has been modified to take into account the non-linearity of large-amplitude synchrotron motion in a particle accelerator. This permits the accurate reconstruction of longitudinal phase space density from one-dimensional bunch profile data. The algorithm was developed in Mathematica TM in order to exploit the extensive built-in functions and graphics. Subsequently, it has been recoded in Fortran 90 with the aim of reducing the execution time by at least a factor of one hundred. The choice of Fortran 90 was governed by the desire ultimately to exploit parallel architectures, but sequential compilation and execution have already largely yielded the required gain in speed. The use of the method to produce longitudinal phase space plots, animated sequences o...

Longitudinal study of sexual function and vaginal changes after radiotherapy for cervical cancer

DEFF Research Database (Denmark)

Jensen, Pernille T; Groenvold, Mogens; Klee, Marianne C

2003-01-01

. The patients were assessed, using a validated self-assessment questionnaire, at the termination of RT and 1, 3, 6, 12, 18, and 24 months later. The results were compared with an age-matched control group from the general population. RESULTS: Persistent sexual dysfunction and adverse vaginal changes were......PURPOSE: To investigate the longitudinal course of self-reported sexual function and vaginal changes in patients disease free after radiotherapy (RT) for locally advanced, recurrent, or persistent cervical cancer. MATERIALS AND METHODS: A total of 118 patients referred for RT were included...... reported throughout the 2 years after RT, with small changes over time: approximately 85% had low or no sexual interest, 35% had moderate to severe lack of lubrication, 55% had mild to severe dyspareunia, and 30% were dissatisfied with their sexual life. A reduced vaginal dimension was reported by 50...

Longitudinal behavioral analysis during dental care of children aged 0 to 3 years

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Robson Frederico Cunha

2009-09-01

Full Text Available "When" and "how" the dentist intervenes have repercussions on children's physical and emotional patterns. The objective of the present study was to conduct a longitudinal behavioral analysis during dental care of babies aged 0 to 3 years. A total of 216 patients seen at the Baby Clinic of the School of Dentistry at Araçatuba, São Paulo State University (UNESP, were selected. The selection criterion was attendance at ten dental care sessions at bimonthly intervals for routine procedures such as clinical examination and oral hygiene. There was a predominance of cooperative behavior compared to uncooperative behavior when each visit was analyzed separately. The behavior of the patients must have been directly influenced by their psychomotor development. Constant attendance and exposure of the baby to non-stressful dental stimuli are factors that favor a cooperative behavior.

Correlation between Left Ventricular Global and Regional Longitudinal Systolic Strain and Impaired Microcirculation in Patients with Acute Myocardial Infarction

DEFF Research Database (Denmark)

Løgstrup, Brian B; Høfsten, Dan Eik; Christophersen, Thomas Brøcher

2012-01-01

investigated if LRS and GLS imaging is superior to conventional measures of left ventricle (LV) function. Methods: In a consecutive population of first time AMI patients, who underwent successful revascularization, we performed comprehensive TTE. GLS and LRS were obtained from the three standard apical views...... elevation myocardial infarction. The GLS was -15.2 [-19.3;-10.1]% in the total population of 183 patients. Total wall motion score index (WMSI) in the population was 1.19 [1;1.5]. Eighty-five patients suffered from culprit lesion in left anterior descending artery (LAD). The CFR in these patients was 1......Objectives: We investigated the correlation between left ventricular global and regional longitudinal systolic strain (GLS and LRS) and coronary flow reserve (CFR) assessed by transthoracic echocardiography (TTE) in patients with a recent acute myocardial infarction (AMI). Furthermore, we...

The Timing of Maternal Depressive Symptoms and Child Cognitive Development: A Longitudinal Study

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Evans, Jonathan; Melotti, Roberto; Heron, Jon; Ramchandani, Paul; Wiles, Nicola; Murray, Lynne; Stein, Alan

2012-01-01

Background: Maternal depression is known to be associated with impairments in child cognitive development, although the effect of timing of exposure to maternal depression is unclear. Methods: Data collected for the Avon Longitudinal Study of Parents and Children, a longitudinal study beginning in pregnancy, included self-report measures of…

Changes in HRM in Europe: A Longitudinal Comparative Study among 18 European Countries

Science.gov (United States)

Nikandrou, Irene; Apospori, Eleni; Papalexandris, Nancy

2005-01-01

Purpose: To examine HRM strategies and practices and HRM position within organizations in various cultural, economic and sociopolitical contexts from a longitudinal perspective. Design/methodology/approach: The study uses the 1995 and 1999 Cranet data in a longitudinal methodological framework to explore the changes and trends in 18 European…

Substance Use as a Longitudinal Predictor of the Perpetration of Teen Dating Violence

Science.gov (United States)

Temple, Jeff R.; Shorey, Ryan C.; Fite, Paula; Stuart, Gregory L.; Le, Vi Donna

2013-01-01

The prevention of teen dating violence is a major public health priority. However, the dearth of longitudinal studies makes it difficult to develop programs that effectively target salient risk factors. Using a school-based sample of ethnically diverse adolescents, this longitudinal study examined whether substance use (alcohol, marijuana, and…

Total average diastolic longitudinal displacement by colour tissue doppler imaging as an assessment of diastolic function

DEFF Research Database (Denmark)

de Knegt, Martina Chantal; Biering-Sørensen, Tor; Søgaard, Peter

2016-01-01

of LD during early diastole and atrial contraction, can potentially be used as a simple and reliable alternative. METHODS: In 206 patients, using GE Healthcare Vivid E7 and 9 and Echopac BT11 software, we determined both diastolic LD, measured in the septal and lateral walls in the apical 4-chamber view...... by TDI, and the degree of diastolic dysfunction, based on current guidelines. Of these 206 patients, 157 had cardiac anomalies that could potentially affect diastolic LD such as severe systolic heart failure (n = 45), LV hypertrophy (n = 49), left ventricular (LV) dilation (n = 30), and mitral...... for the general discrimination of patients with or without diastolic dysfunction. Using linear regression, total average diastolic LD was estimated to fall by 2.4 mm for every increase in graded severity of diastolic dysfunction (β = -0.61, p-value

Normative changes in interests from adolescence to adulthood: A meta-analysis of longitudinal studies.

Science.gov (United States)

Hoff, Kevin A; Briley, Daniel A; Wee, Colin J M; Rounds, James

2018-04-01

Vocational interests predict a variety of important outcomes and are among the most widely applied individual difference constructs in psychology and education. Despite over 90 years of research, little is known about the longitudinal development of interests. In this meta-analysis, the authors investigate normative changes in interests through adolescence and young adulthood. Effect sizes were aggregated from 49 longitudinal studies reporting mean-level changes in vocational interests, containing 98 total samples and 20,639 participants. Random effects meta-analytic regression models were used to assess age-related changes and gender differences across Holland's (1959, 1997) RIASEC categories and composite dimensions (people, things, data, and ideas). Results showed that mean-level interest scores generally increase with age, but effect sizes varied across interest categories and developmental periods. Adolescence was defined by two broad patterns of change: interest scores generally decreased during early adolescence, but then increased during late adolescence. During young adulthood, the most striking changes were found across the people and things orientations. Interests involving people tended to increase (artistic, social, and enterprising), whereas interests involving things either decreased (conventional) or remained constant (realistic and investigative). Gender differences associated with occupational stereotypes reached a lifetime peak during early adolescence, then tended to decrease in all subsequent age periods. Overall findings suggest there are normative changes in vocational interests from adolescence to adulthood, with important implications for developmental theories and the applied use of interests. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The benefits of personal strengths in mental health of stressed students: A longitudinal investigation.

Science.gov (United States)

Duan, Wenjie

2016-11-01

This study used a two-wave longitudinal research design to explore the role of individual strengths, including interpersonal strength, intellectual strength, and temperance strength, in affecting the mental health of stressed college students. A total of 404 stressed Chinese college students were screened to participate in this 12-month longitudinal study. At the beginning of the study (Time 1), students who had not experienced stressful events within the last 12 months were invited to assess their strengths, psychological well-being, and psychological symptoms. After 12 months (Time 2), 404 students who reported stressful experiences completed the scales again and were retained for the final analyses. Academics-related stressors were the most endorsed life events among college students, whose states of mental health showed downward trends from Time 1 to Time 2. Three strengths had weak to modest correlations to mental health at both Time 1 and Time 2. Although the additional variances of mental health explained by the three strengths were very modest, the mediational roles of the strengths were identified. The perceived stress completely mediated the relationship between the strengths and the psychological symptoms and partly mediated the relationship between the strengths and psychological well-being. Individual strengths may function as a defense against perceived stress and are protective factors of mental health. These strengths maintain mental health by enhancing the psychological well-being and reducing the psychological symptoms of individuals.

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

Science.gov (United States)

Chen, Tianle; Zeng, Donglin

2015-01-01

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

Prenatal stress and risk of febrile seizures in children: a nationwide longitudinal study in Denmark

DEFF Research Database (Denmark)

Li, Jiong; Olsen, Jørn; Obel, Carsten

2009-01-01

We aimed to examine whether exposure to prenatal stress following maternal bereavement is associated with an increased risk of febrile seizures. In a longitudinal population-based cohort study, we followed 1,431,175 children born in Denmark. A total of 34,777 children were born to women who lost...... a close relative during pregnancy or within 1 year before the pregnancy and they were included in the exposed group. The exposed children had a risk of febrile seizures similar to that of the unexposed children (hazard ratio (HR) 1.00, 95% CI 0.94-1.06). The HRs did not differ according to the nature...... or timing of bereavement. Our data do not suggest any causal link between exposure to prenatal stress and febrile seizures in childhood....

Longitudinal effects of ionospheric responses to substorms at middle and lower latitudes: a case study

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X. Pi

1995-08-01

Full Text Available An ionospheric model is used to simulate total electron content (TEC disturbance events observed at middle and lower latitude sites near 75°W and 7°E longitudes. Within this longitudinal range, daytime TEC disturbances show patterns that are correlated with substrom activity seen in both auroral electrojet and ring current behavior. In modeling studies of the observed ionospheric effects, both electric field and neutral wind perturbations are examined as possible mechanisms. The morphological features of the required electric field perturbations near drawn and dusk are compared with those at other times to examine the local time characteristics of magnetospheric influence. Large-scale traveling atmospheric disturbances (TADs, an alternative candidate for the disturbance source, are also characterized and compared with known thermospheric behavior.

Longitudinal Research on Aging Drivers (LongROAD): study design and methods.

Science.gov (United States)

Li, Guohua; Eby, David W; Santos, Robert; Mielenz, Thelma J; Molnar, Lisa J; Strogatz, David; Betz, Marian E; DiGuiseppi, Carolyn; Ryan, Lindsay H; Jones, Vanya; Pitts, Samantha I; Hill, Linda L; DiMaggio, Charles J; LeBlanc, David; Andrews, Howard F

2017-12-01

As an important indicator of mobility, driving confers a host of social and health benefits to older adults. Despite the importance of safe mobility as the population ages, longitudinal data are lacking about the natural history and determinants of driving safety in older adults. The Longitudinal Research on Aging Drivers (LongROAD) project is a multisite prospective cohort study designed to generate empirical data for understanding the role of medical, behavioral, environmental and technological factors in driving safety during the process of aging. A total of 2990 active drivers aged 65-79 years at baseline have been recruited through primary care clinics or health care systems in five study sites located in California, Colorado, Maryland, Michigan, and New York. Consented participants were assessed at baseline with standardized research protocols and instruments, including vehicle inspection, functional performance tests, and "brown-bag review" of medications. The primary vehicle of each participant was instrumented with a small data collection device that records detailed driving data whenever the vehicle is operating and detects when a participant is driving. Annual follow-up is being conducted for up to three years with a telephone questionnaire at 12 and 36 months and in-person assessment at 24 months. Medical records are reviewed annually to collect information on clinical diagnoses and healthcare utilization. Driving records, including crashes and violations, are collected annually from state motor vehicle departments. Pilot testing was conducted on 56 volunteers during March-May 2015. Recruitment and enrollment were completed between July 2015 and March 2017. Results of the LongROAD project will generate much-needed evidence for formulating public policy and developing intervention programs to maintain safe mobility while ensuring well-being for older adults.

Approaches in methodology for population-based longitudinal study on neuroprotective model for healthy longevity (TUA) among Malaysian Older Adults.

Science.gov (United States)

Shahar, Suzana; Omar, Azahadi; Vanoh, Divya; Hamid, Tengku Aizan; Mukari, Siti Zamratol Mai-Sarah; Din, Normah Che; Rajab, Nor Fadilah; Mohammed, Zainora; Ibrahim, Rahimah; Loo, Won Hui; Meramat, Asheila; Kamaruddin, Mohd Zul Amin; Bagat, Mohamad Fazdillah; Razali, Rosdinom

2016-12-01

A number of longitudinal studies on aging have been designed to determine the predictors of healthy longevity, including the neuroprotective factors, however, relatively few studies included a wide range of factors and highlighted the challenges faced during data collection. Thus, the longitudinal study on neuroprotective model for healthy longevity (LRGS TUA) has been designed to prospectively investigate the magnitude of cognitive decline and its risk factors through a comprehensive multidimensional assessment comprising of biophysical health, auditory and visual function, nutrition and dietary pattern and psychosocial aspects. At baseline, subjects were interviewed for their status on sociodemographic, health, neuropsychological test, psychosocial and dietary intake. Subjects were also measured for anthropometric and physical function and fitness. Biospecimens including blood, buccal swap, hair and toenail were collected, processed and stored. A subsample was assessed for sensory function, i.e., vision and auditory. During follow-up, at 18 and 36 months, most of the measurements, along with morbidity and mortality outcomes will be collected. The description of mild cognitive impairment, successful aging and usual aging process is presented here. A total 2322 respondents were recruited in the data analysis at baseline. Most of the respondents were categorized as experiencing usual aging (73 %), followed by successful aging (11 %) and mild cognitive impairment (16 %). The LRGS TUA study is the most comprehensive longitudinal study on aging in Malaysia, and will contribute to the understanding of the aging process and factors associated with healthy aging and mental well-being of a multiethnic population in Malaysia.

The longitudinal association of common susceptibility variants for type 2 diabetes and obesity with fasting glucose level and BMI

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Beilby John P

2010-10-01

Full Text Available Abstract Background Variation in the effects of genetic variants on physiological traits over time or with age may alter the trajectories of these traits. However, few studies have investigated this possibility for variants associated with type 2 diabetes or obesity, and these show little consensus. We aimed to characterise the possible longitudinal associations of common diabetes-susceptibility variants in the KCNJ11, PPARG, TCF7L2, IGF2BP2, CDKAL1, SLC30A8 and HHEX gene loci, with fasting glucose level; and of an obesity-associated variant in the FTO gene, with body mass index (BMI. Methods The study analysed data from the Busselton Health Study (n = 4,554. Cross-sectional association analyses included family data and used the total association test. Longitudinal association analyses of unrelated participant data (n = 2,864 used linear mixed-effects models. Results In cross-sectional analyses, we observed associations of the T allele at the IGF2BP2 single nucleotide polymorphism (SNP rs4402960 with raised fasting glucose (p = 0.045, and the A allele at the FTO SNP rs9939609 with raised BMI (p = 0.003. Longitudinal analyses showed no significant associations between SNPs and changes in fasting glucose or BMI in the same individuals, either over mean follow-up times of 18.7 and 21.8 years respectively, or with age during adulthood. Conclusions There was no indication that the effects of common type 2 diabetes variants on fasting glucose varied with age during adulthood or over time.

Young's modulus of BF wood material by longitudinal vibration

International Nuclear Information System (INIS)

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

2014-01-01

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.

Facebook: an effective tool for participant retention in longitudinal research.

Science.gov (United States)

Mychasiuk, R; Benzies, K

2012-09-01

Facebook is currently one of the world's most visited websites, and home to millions of users who access their accounts on a regular basis. Owing to the website's ease of accessibility and free service, demographic characteristics of users span all domains. As such, Facebook may be a valuable tool for locating and communicating with participants in longitudinal research studies. This article outlines the benefit gained in a longitudinal follow-up study, of an intervention programme for at-risk families, through the use of Facebook as a search engine. Using Facebook as a resource, we were able to locate 19 participants that were otherwise 'lost' to follow-up, decreasing attrition in our study by 16%. Additionally, analysis indicated that hard-to-reach participants located with Facebook differed significantly on measures of receptive language and self-esteem when compared to their easier-to-locate counterparts. These results suggest that Facebook is an effective means of improving participant retention in a longitudinal intervention study and may help improve study validity by reaching participants that contribute differing results. © 2011 Blackwell Publishing Ltd.

A rotary piezoelectric actuator using longitudinal and bending hybrid transducer

Directory of Open Access Journals (Sweden)

Yingxiang Liu

2012-12-01

Full Text Available A rotary piezoelectric actuator using bolt-clamped type transducer with double driving feet is proposed in this study. The first-order longitudinal and fourth-order bending vibration modes are superimposed in the actuator to produce elliptical movements on the driving tips. Longitudinal PZT and bending PZT are clamped between the exponential shape horns and the flange by bolts. The vibration shape changes of the actuator are presented to give a clear explanation of its working principle. Several structural parameters of the exponential shape horn are selected and adjusted to accomplish the tuning process of the longitudinal and bending resonance frequencies. The input impedance and vibration characteristics are calculated by using FEM method; the gained results verify the feasibility of the proposed actuator. After the fabrication of a prototype, its vibration characteristics are measured by using a scanning laser Doppler vibrometer; the tested results are in good agreement with the FEM calculated results. The mechanical output performance experiments state that the prototype achieves a maximum speed of 129 r/min and a maximum torque of 1.5 Nm.

Substantia Nigra Free Water Increases Longitudinally in Parkinson Disease.

Science.gov (United States)

Guttuso, T; Bergsland, N; Hagemeier, J; Lichter, D G; Pasternak, O; Zivadinov, R

2018-02-01

Free water in the posterior substantia nigra obtained from a bi-tensor diffusion MR imaging model has been shown to significantly increase over 1- and 4-year periods in patients with early-stage idiopathic Parkinson disease compared with healthy controls, which suggests that posterior substantia nigra free water may be an idiopathic Parkinson disease progression biomarker. Due to the known temporal posterior-to-anterior substantia nigra degeneration in idiopathic Parkinson disease, we assessed longitudinal changes in free water in both the posterior and anterior substantia nigra in patients with later-stage idiopathic Parkinson disease and age-matched healthy controls for comparison. Nineteen subjects with idiopathic Parkinson disease and 19 age-matched healthy control subjects were assessed on the same 3T MR imaging scanner at baseline and after approximately 3 years. Baseline mean idiopathic Parkinson disease duration was 7.1 years. Both anterior and posterior substantia nigra free water showed significant intergroup differences at baseline ( P Parkinson disease versus healthy controls); however, only anterior substantia nigra free water showed significant longitudinal group × time interaction increases ( P = .021, idiopathic Parkinson disease versus healthy controls). There were no significant longitudinal group × time interaction differences found for conventional diffusion tensor imaging or free water-corrected DTI assessments in either the anterior or posterior substantia nigra. Results from this study provide further evidence supporting substantia nigra free water as a promising disease-progression biomarker in idiopathic Parkinson disease that may help to identify disease-modifying therapies if used in future clinical trials. Our novel finding of longitudinal increases in anterior but not posterior substantia nigra free water is potentially a result of the much longer disease duration of our cohort compared with previously studied cohorts and the known

The longitudinal wall impedance instability in a heavy-ion fusion driver

International Nuclear Information System (INIS)

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

1997-01-01

For more than ten years [J. Bisognano, I. Haber, L. Smith, IEEE Trans. Nucl. Sci. NS-30, 2501 (1983)], the longitudinal wall impedance instability was thought to be a serious threat to the success of heavy-ion driven inertial confinement fusion. This instability is a open-quotes resistive wallclose quotes instability, driven by the impedance of the induction modules used to accelerate the beam. Early estimates of the instability growth rate predicted tens of e-folds due to the instability which would modulate the current and increase the longitudinal momentum spread and prevent focusing the ion beam on the small spot needed at the target. We have simulated this instability using an r-z particle-in-cell code which includes a model for the module impedance. These simulations, using driver parameters, show that growth due to the instability is smaller than in previous calculations. We have seen that growth is mainly limited to one head to tail transit by a space-charge wave. In addition, the capacitive component of the module impedance, which was neglected in the early work of Lee [E. P. Lee, Proc. Linear Accelerator Conference, (UCRL-86452), Santa Fe, NM, 1981] significantly reduces the growth rate. We have also included in the simulation intermittently applied axial confining fields which are thought to be the major source of perturbations to seed the longitudinal instability. Simulations show the beam can adjust to a systematic error in the longitudinal confining fields while a random error excites the most unstable wavelength of the instability. These simulations show that the longitudinal instability must be taken into account in a driver design, but it is not the major factor it was once thought to be. copyright 1997 American Institute of Physics

Stability of longitudinal oscillations of a bunch propagating through an evacuated chamber with reactive impedance

International Nuclear Information System (INIS)

Besnier, G.

1979-01-01

The longitudinal space-charge force is assumed to vary like the derivative of the longitudinal beam density. Solutions of the linearized Vlasov equation are then given as an expansion of normal modes for the longitudinal phase-space density of a bunched beam. For a given bunch intensity, the method allows calculation of the required synchrotron frequency spread inside a parabolic bunch, in order to stabilize the beam against coherent oscillations by Landau-damping. (Auth.)

The Czech longitudinal study of optimal development

Czech Academy of Sciences Publication Activity Database

Kebza, V.; Šolcová, Iva; Kodl, M.; Kernová, V.

2012-01-01

Roč. 47, Suppl. 1 (2012), s. 266-266 ISSN 0020-7594. [International Congress of Psychology /30./. 22.07.2012-27.07.2012, Cape Town] R&D Projects: GA ČR GAP407/10/2410 Institutional support: RVO:68081740 Keywords : optimal development * Prague longitudinal study Subject RIV: AN - Psychology

Passive Control System for Mitigation of Longitudinal Buffeting Responses of a Six-Tower Cable-Stayed Bridge

Directory of Open Access Journals (Sweden)

Fangfang Geng

2016-01-01

Full Text Available This paper presents an investigation of mitigation of longitudinal buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of longitudinal buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects of insufficient longitudinal stiffness of central towers and partially longitudinal constraints between the bridge deck and part of bridge towers. The effectiveness of viscous fluid dampers on the mitigation of longitudinal buffeting responses of the bridge is further investigated and a multiobjective optimization design method that uses a nondominating sort genetic algorithm II (NSGA-II is used to optimize parameters of the viscous fluid dampers. The results of the parametric investigations show that, by appropriate use of viscous fluid dampers, the top displacements of central towers and base forces of bridge towers longitudinally restricted with the bridge deck can be reduced significantly, with hampering the significant gain achieved in the base forces of bridge towers longitudinally unrestricted with the bridge deck. And the optimized parameters for the viscous fluid dampers can be determined from Pareto-optimal fronts using the NSGA-II that can satisfy the desired performance requirements.

Longitudinal study on osteoarthritis and bone metabolism

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L. Postiglione

2011-09-01

Full Text Available Objective: The relationship between Osteoarthritis (OA and Osteoporosis (OP is not well defined due to lacking in longitudinal data, mainly regarding correlations between biochemical factors and OA incidence. Aim of this paper was to investigate the predictive value for OA incidence of bone mass variations and of selected biochemical markers in healthy women participating in a population-based longitudinal study carried out in Naples (Italy. Subjects and Methods: High completion rate (85.2% and statistically adequate sample size were obtained: 139 women (45 to 79 years of age were examined and follow up visit was performed after two years (24±2 months, following the same protocol. Patients underwent medical examination, questionnaire, anthropometric measurements, blood sampling and urine collection. Bone mineral density (BMD measurement was performed by dual energy X-ray absorptiometry (DEXA at the lumbar spine (L1-L4 and femoral neck. Radiographs of dorsal and lumbar spine in lateral view were performed at basal and at 24 months visits; a team of three experts scored radiographs using Kellegren and Lawrence grading. Results: The score was calculated for two individual radiographic features (narrowing of the joint space, presence of osteophytes and as a global score. Results show a relevant percentage, 23% up, of subjects presenting both OA and OP. In the cross-sectional study the presence of osteophytosis correlates with anthropometric variables and PTH levels. In the longitudinal study results show a correlation between serum vitamin D and delta score for osteophytosis (β=0.02 p<0.05. Conclusions: Data obtained outline the importance of further studies on the pathogenetic link between OA and bone metabolism.

Effects of varying the longitudinal dispersion and no drip cask rate failures upon Yucca Mountain site performance

International Nuclear Information System (INIS)

Winterle, Bret

2001-01-01

Proposed changes in the regulatory time limits used for viability assessments of the proposed national high-level radioactive waste repository in Yucca Mountain, Nevada from 10,000 years to 100,000 or even 1,000,000 years call into question both the modelling techniques used to represent the repository's long-term performance, and our ability to extrapolate technological, climatological and geological phenomenon. Using a high-powered risk-assessment software program called Goldsim that a simplified total system performance assessment (STSPA) was designed for, the effects of varying the performance parameters of two barrier systems, one natural and one man-made, upon the total system performance were observed. The conclusion reached by varying these two parameters is that for a regulatory guideline of 10,000 years, there is no noticeable effect on the total system performance, but at 300,000 years, it appears that the effect of reducing the longitudinal dispersion rate (a natural barrier) by one order of magnitude produced an astronomically high receptor dose, indicating that as predicted, our abilities to model situations beyond our ability to accurately extrapolate current scientific research is futile. (author)

Effects of varying the longitudinal dispersion and no drip cask rate failures upon Yucca Mountain site performance

Energy Technology Data Exchange (ETDEWEB)

Winterle, Bret

2001-07-01

Proposed changes in the regulatory time limits used for viability assessments of the proposed national high-level radioactive waste repository in Yucca Mountain, Nevada from 10,000 years to 100,000 or even 1,000,000 years call into question both the modelling techniques used to represent the repository's long-term performance, and our ability to extrapolate technological, climatological and geological phenomenon. Using a high-powered risk-assessment software program called Goldsim that a simplified total system performance assessment (STSPA) was designed for, the effects of varying the performance parameters of two barrier systems, one natural and one man-made, upon the total system performance were observed. The conclusion reached by varying these two parameters is that for a regulatory guideline of 10,000 years, there is no noticeable effect on the total system performance, but at 300,000 years, it appears that the effect of reducing the longitudinal dispersion rate (a natural barrier) by one order of magnitude produced an astronomically high receptor dose, indicating that as predicted, our abilities to model situations beyond our ability to accurately extrapolate current scientific research is futile. (author)

[Depressive symptoms and related factors among primary and middle school students in Changfeng county of Anhui province:a two-year longitudinal study].

Science.gov (United States)

Zhao, Xue; Yang, Linsheng; Chen, Mingchun; Chen, Jian; Lyu, Xiaoling; Jiang, Yuhong; Sun, Ying; Sun, Yehuan

2014-05-01

To assess the prevalence of depressive symptoms, trends on its longitudinal development and related influencing factors among primary and middle school students in Changfeng county of Anhui province. Through cluster sampling methods, all students from 3 to 9 grades in 5 primary schools and 3 middle schools in Changfeng county of Anhui province were investigated through questionnaire as subjects of baseline survey in December 2009. Subjects of this longitudinal study were students in grades 3, 4 and 7 at the time of the baseline survey and were contacted once a year for two years. At last, a total of 816 students participated in all the three surveys. A structured questionnaire including Children's Depression Inventory, socio-demographic characteristics and some potential influential factors was employed for this study. A Generalized Estimating Equation (GEE) was used to evaluate the related influencing factors of children's depressive symptoms in the longitudinal study. Prevalence rates of depressive symptoms were 11.3% , 10.4% and 8.5% , respectively, at the baseline, 1-year and 2-year follow-up studies, among primary and middle school students. Scores on depressive symptoms of total subjects and children who had always been left at home in the follow-up process showed significant differences at the three surveys (F = 13.423, P students who showed depressive symptoms at the baseline survey remained those depressive symptoms at the 1-year follow-up study and 87 percent of the 23 students who had depressive symptoms at the baseline and 1-year follow-up surveys still showing depressive symptoms at the 2-year follow-up study. Results from the GEE program indicated that grade 3 students, having syblings, family with dysfunction or at low level of self-esteem etc., were prone to development while sex and parents' educational level were not correlated with depressive symptoms. Prevalence of depressive symptoms among primary and middle school students in Changfeng county

Longitudinal Associations of Leptin and Adiponectin with Heart Rate Variability in Children

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Roos Van De Wielle

2017-07-01

Full Text Available For early prevention of cardiovascular disease, early detection and risk factor insights are necessary. The autonomic balance reflects cardiovascular risk and can be measured by heart rate variability (HRV. Therefore, our purpose is to examine associations between HRV and the energy-related biomarkers leptin and adiponectin in children. Participants of this study were Belgian children recruited for the longitudinal ChiBS study (year 2010–2012. HRV was measured and fasting blood samples were taken in 249 children at baseline (4.4–11.0 y and 223 children at follow-up (6.7–12.2 y. Cross-sectional and longitudinal linear regression analyses were separated by sex and adjusted for age, socio-economic status, body fat%, negative emotions, puberty, and mean heart rate. Leptin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; while leptin in girls was cross-sectionally associated with higher LF and LF/HF suggesting sympathetic predominance. Adiponectin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; but when adjusting for mean heart rate, this effect disappeared and adiponectin was a positive cross-sectional and longitudinal predictor of parasympathetic activity in girls. These results stress the importance of considering sex differences and adjustment for heart rate in testing HRV predictors. Leptin seemed disadvantageous for the autonomic balance, while adiponectin seemed advantageous for the autonomic balance in girls only. More research is needed to see whether leptin and adiponectin are interesting in cardiovascular screening/prevention or in determining the cardiovascular gain during weight loss follow-up.

Elastic stability of biaxially loaded longitudinally stiffened composite structures.

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Viswanathan, A. V.; Tamekuni, M.; Tripp, L. L.

1973-01-01

A linear analysis method is presented for the elastic stability of structures of uniform cross section, that may be idealized as an assemblage of laminated plate-strips, flat and curved, and beams. Each plate-strip and beam covers the entire length of the structure and is simply supported on the edges normal to the longitudinal axis. Arbitrary boundary conditions may be specified on any external longitudinal side of plate-strips. The structure or selected plate-strips may be loaded in any desired combination of inplane biaxial loads. The analysis simultaneously considers all modes of instability and is applicable for the buckling of laminated composite structures. Some numerical results are presented to indicate possible applications.

Laser wakefield excitation and measurement by femtosecond longitudinal interferometry

International Nuclear Information System (INIS)

Siders, C.W.; Le Blanc, S.P.; Fisher, D.; Tajima, T.; Downer, M.C.

1996-04-01

Plasma density oscillations (Langmuir waves) in the wake of an intense (I peak ∼ 3 x 10 17 W/cm 2 ) laser pulse (100 fs) are measured with ultrafast time resolution using a longitudinal interferometric technique. Phase shifts consistent with large amplitude (δn e /n e ∼ 1) density waves at the electron plasma frequency were observed in a fully tunnel-ionized He plasma, corresponding to longitudinal electric fields of ∼ 10 GV/m. Strong radial ponderomotive forces enhance the density oscillations. As this technique utilizes a necessary component of any laser-based plasma accelerator, it promises to be a powerful tool for on-line monitoring and control of future plasma-based particle accelerators

The Effects of the Green House Nursing Home Model on ADL Function Trajectory: A Retrospective Longitudinal Study

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YOON, Ju Young; BROWN, Roger L.; BOWERS, Barbara J.; SHARKEY, Siobhan S.; HORN, Susan D.

2015-01-01

Background Growing attention in the past few decades has focused on improving care quality and quality of life for nursing home residents. Many traditional nursing homes have attempted to transform themselves to become more homelike emphasizing individualized care. This trend is referred to as nursing home culture change in the U.S. A promising culture change nursing home model, the Green House (GH) nursing home model, has shown positive psychological outcomes. However, little is known about whether the GH nursing home model has positive effects on physical function compared to traditional nursing homes. Objectives To examine the longitudinal effects of the GH nursing home model by comparing change patterns of ADL function over time between GH home residents and traditional nursing home residents. Design A retrospective longitudinal study. Settings Four GH organizations (nine GH units and four traditional units). Participants A total of 242 residents (93 GH residents and 149 traditional home residents) who had stayed in the nursing home at least six months from admission. Methods The outcome was ADL function, and the main independent variable was the facility type in which the resident stayed: a GH or traditional unit. Age, gender, comorbidity score, cognitive function, and depressive symptoms at baseline were controlled. All of these measures were from a minimum dataset. Growth curve modeling and growth mixture modeling were employed in this study for longitudinal analyses. Results The mean ADL function showed deterioration over time, and the rates of deterioration between GH and traditional home residents were not different over time. Four different ADL function trajectories were identified for 18 months, but there was no statistical difference in the likelihood of being in one of the four trajectory classes between the two groups. Conclusions Although GH nursing homes are considered to represent an innovative model changing the nursing home environment into more

Longitudinal tune control in synchrotrons

International Nuclear Information System (INIS)

Colton, E.P.

1984-01-01

Dual rf systems that use fundamental and higher-harmonic cavities can be used to control the longitudinal tune in synchrotrons. The equations of motion and the Hamiltonian are defined for particle motion using dual rf systems. An example is considered using a second-harmonic system - it is shown, that as phi/sub s/ is increased, a substantial gain in bucket area over a single rf system can be realized by proper relative phasing of the first- and second-harmonic voltages

An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia.

Science.gov (United States)

Malkoc, Melih; Korkmaz, Ozgur; Ormeci, Tugrul; Oltulu, Ismail; Isyar, Mehmet; Mahirogulları, Mahir

2014-01-01

Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral. This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia. Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia. Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

The longitudinal impact of hearing impairment on cognition differs according to cognitive domain

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Yasue Uchida

2016-08-01

Full Text Available Identification and modification of the risk factors for cognitive decline throughout the adult life span are priority subjects in a progressively aging society; however, much remains to be learned. The aim of this study was to understand whether changes in cognitive function can be affected by hearing impairment (HI and whether the impact of HI differs depending on the cognitive domain. A total of 1,109 individuals aged 60 – 79 years at baseline who participated in the Longitudinal Study of Aging at the National Institute for Longevity Sciences (NILS-LSA was followed up for a maximum of 13.3 years. Cognitive function was evaluated using four subtests of the Japanese Wechsler Adult Intelligence Scale-Revised Short Forms: namely, Information, Similarities, Picture Completion, and the Digit Symbol Substitution subtests. The HI was defined as a pure-tone average of the better ear greater than 25 dB. A longitudinal analysis was performed of 4,437 observations obtained during a follow-up period of approximately 12 years. We estimated linear changes in subtest scores by HI status, using the time-varying mixed-effects regression model, which included fixed terms for the intercept, HI status at baseline, time (years elapsed since baseline, and an HI × time interaction term adjusted for age at baseline, sex, education, and other possible confounders. There were significant main effects of HI on the scores of the four subtests after adjustment. The HI × time interaction was significant for the scores of the Information (p = 0.001 and Digit Symbol Substitution subtests (p = 0.001. The scores of the HI group declined faster in the Information and Digit Symbol Substitution subtests compared to those of the no-HI group. The model-predicted 12-year slope using a mean baseline age (68.7 years indicated no significant decline in the individuals without HI at baseline for the Information and Similarities subtests, however, this tolerance was lost in the

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

Science.gov (United States)

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

2010-01-01

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

Chrometric properties of curvilinear beam transport channels with reverses of longitudinal magnetic field

International Nuclear Information System (INIS)

Kapchinskij, M.I.; Korenev, I.L.; Roginskij, L.A.

1990-01-01

Dynamics of charged particle beams in curvilinear transport channels comprising sections with counter direction of longitudinal focusing magnetic field is considered. It is shown that such magnetic field reverses reduce sufficiently the particle deflections conditioned by momentum spread of longitudinal motion and their application allows one to completely project the achromatic channel

Regional vulnerability of longitudinal cortical association connectivity

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Rafael Ceschin

2015-01-01

Full Text Available Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL, are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4 and 75 healthy controls (mean age 5.7 ± 3.4. Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS and voxel-based morphometry (VBM demonstrating diffusely reduced fractional anisotropy (FA reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1 reduced regional posterior–anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation correlated with reduced posterior–anterior gradient of intra-regional (nodal efficiency metrics with relative sparing of frontal and temporal regions; and (2 reduced regional FA within frontal–thalamic–striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract