Science.gov

Sample records for al cortante longitudinal

  1. Psychosocial adjustment to ALS: a longitudinal study.

    PubMed

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

    2015-01-01

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

  2. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

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

    2015-01-01

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

  3. Simulation of the ALS longitudinal multibunch feedback system

    SciTech Connect

    Byrd, J.

    1993-05-01

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

  4. Longitudinal and transverse feedback kickers for the ALS

    SciTech Connect

    Corlett, J.N.; Johnson, J.; Lambertson, G.; Voelker, F.

    1994-06-01

    We describe the development of electromagnetic kickers for coupled-bunch feedback systems at the ALS. Transverse kickers are of a stripline design with one kicker per plane, operating in the baseband, 10 kHz to 250 MHz. Longitudinal lockers are of a coaxial design with electrodes paired in series operating over the band 1.00 to 1.25 GHz. Operating-band measurements and parasitic impedance measurements are presented. Power levels from beam induced signals are presented. Fabrication techniques are discussed.

  5. Raman scattering by longitudinal acoustic phonons in a three-component {Ta}/{Al} Fibonacci superlattice

    NASA Astrophysics Data System (ADS)

    Pan, F. M.; Jin, G. J.; Wu, X. S.; Wu, X. L.; Hu, A.; Jiang, S. S.

    1997-02-01

    Raman scattering from longitudinal acoustic phonons in a three-component {Ta}/{Al} Fibonacci superlattice is studied both experimentally and theoretically. Based on the Kronig-Penney model, the normal-mode frequencies and the relative intensities are calculated by using a transfer-matrix method. Good agreement between the measured and quantitative results is obtained. The phonon spectra exhibit a rich structure of gaps which correlate with the positions of the measured Raman-activated peaks. The Raman peaks are successfully labeled by the the quasiperiodicity index ( p, q, r).

  6. Operation and performance of the PEP-II prototype longitudinal damping system at ALS

    SciTech Connect

    Teytelman, D.; Claus, R.; Fox, J.

    1995-05-01

    A modular programmable longitudinal feedback system has been developed as a component of the PEP-II R+D program. This system is based on a family of VME and VXI packaged signal processing functions which implement a general purpose digital feedback controller for accelerators with bunch spacings of 2 ns. A complete PEP-II prototype system has been configured and installed for use at the LBL Advanced Light Source. The system configuration used for tests at the ALS is described and results are presented showing the action of the feedback system. Open and closed loop results showing the detection and calculation of feedback signals from bunch motion are presented and the system is shown to damp coupled-bunch instabilities in the ALS. Use of the system for accelerator diagnostics is illustrated via measurement of grow-damp transients which quantify growth rates without feedback, damping rates with feedback, and identify unstable modes.

  7. Longitudinal evaluation of upper extremity reachable workspace in ALS by Kinect sensor.

    PubMed

    de Bie, Evan; Oskarsson, Bjorn; Joyce, Nanette C; Nicorici, Alina; Kurillo, Gregorij; Han, Jay J

    2017-02-01

    Our objective was to evaluate longitudinal changes in Microsoft Kinect measured upper extremity reachable workspace relative surface area (RSA) versus the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), ALSFRS-R upper extremity sub-scale and Forced Vital Capacity (FVC) in a cohort of patients diagnosed with amyotrophic lateral sclerosis (ALS). Ten patients diagnosed with ALS (ages 52-76 years, ALSFRS-R: 8-41 at entry) were tested using single 3D depth sensor, Microsoft Kinect, to measure reachable workspace RSA across five visits spanning one year. Changes in RSA, ALSFRS-R, ALSFRS-R upper extremity sub-scale, and FVC were assessed using a linear mixed model. Results showed that upper lateral quadrant RSA declined significantly in one year by approximately 19% (p <0.01) while all other quadrants and total RSA did not change significantly in this time-period. Simultaneously, ALSFRS-R upper extremity sub-scale worsened significantly by 25% (p <0.01). In conclusion, upper extremity reachable workspace RSA as a novel ALS outcome measure is capable of objectively quantifying declines in upper extremity ability over time in patients with ALS with more granularity than other common outcome measures. RSA may serve as a clinical endpoint for the evaluation of upper extremity targeted therapeutics.

  8. Speech in ALS: Longitudinal Changes in Lips and Jaw Movements and Vowel Acoustics

    PubMed Central

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Pattee, Gary L.; Zinman, Lorne

    2015-01-01

    Purpose The goal of this exploratory study was to investigate longitudinally the changes in facial kinematics, vowel formant frequencies, and speech intelligibility in individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). This study was motivated by the need to understand articulatory and acoustic changes with disease progression and their subsequent effect on deterioration of speech in ALS. Method Lip and jaw movements and vowel acoustics were obtained for four individuals with bulbar ALS during four consecutive recording sessions with an average interval of three months between recordings. Participants read target words embedded into sentences at a comfortable speaking rate. Maximum vertical and horizontal mouth opening and maximum jaw displacements were obtained during corner vowels. First and second formant frequencies were measured for each vowel. Speech intelligibility and speaking rate score were obtained for each session as well. Results Transient, non-vowel-specific changes in kinematics of the jaw and lips were observed. Kinematic changes often preceded changes in vowel acoustics and speech intelligibility. Conclusions Nonlinear changes in speech kinematics should be considered in evaluation of the disease effects on jaw and lip musculature. Kinematic measures might be most suitable for early detection of changes associated with bulbar ALS. PMID:27453680

  9. Analysis of DSP-based longitudinal feedback system: Trials at SPEAR and ALS

    SciTech Connect

    Hindi, H.; Eisen, N.; Fox, J.; Linscott, I.; Oxoby, G.; Sapozhnikov, L.; Serio, M.

    1993-04-01

    Recently a single-channel prototype of the proposed PEP-II longitudinal feedback system was successfully demonstrated at SPEAR and ALS on single-bunch beams. The phase oscillations are detected via a wide-band pick up. The feedback signal is then computed using a digital signal processor (DSP) and applied to the beam by phase modulating the rf. We analyze results in the frequency- and the time-domain and show how the closed-loop transfer functions can be obtained rigorously by proper modeling of the various components of this hybrid continuous/digital system. The technique of downsampling was used in the experiments to reduce the number of computations and allowed the use of the same digital hardware on both machines.

  10. Multi-Bunch Longitudinal Dynamics and Diagnostics via a Digital Feedback System at PEP-II, DAFNE, ALS and SPEAR

    SciTech Connect

    Fox, John D

    1999-04-19

    A bunch-by-bunch longitudinal feedback system based on a programmable DSP architecture is used to study coupled-bunch motion and its sources. Experimental results are presented from PEP-II, DA{Phi}NE, ALS and SPEAR to highlight the operational experience from 4 installations, plus show novel accelerator diagnostics possible with the digital processing system. Modal growth and damping rates are measured via short (20 ms) transient recordings for unstable and stable coupled-bunch modes. Data from steady-state measurements are used to identify unstable modes and noise-driven beam motion. A novel impedance measurement technique is presented which reveals the longitudinal impedance as a function of frequency. This technique uses the measured synchronous phase and charge of every bucket to calculate the impedance seen by the beam at revolution harmonics.

  11. Analytical Study of the Propagation of Fast Longitudinal Modes along wz-BN/AlN Thin Acoustic Waveguides

    PubMed Central

    Caliendo, Cinzia

    2015-01-01

    The propagation of the fundamental symmetric Lamb mode S0 along wz-BN/AlN thin composite plates suitable for telecommunication and sensing applications is studied. The investigation of the acoustic field profile across the plate thickness revealed the presence of modes having longitudinal polarization, the Anisimkin Jr. plate modes (AMs), travelling at a phase velocity close to that of the wz-BN longitudinal bulk acoustic wave propagating in the same direction. The study of the S0 mode phase velocity and coupling coefficient (K2) dispersion curves, for different electrical boundary conditions, has shown that eight different coupling configurations are allowable that exhibit a K2 as high as about 4% and very high phase velocity (up to about 16,700 m/s). The effect of the thickness and material type of the metal floating electrode on the K2 dispersion curves has also been investigated, specifically addressing the design of an enhanced coupling device. The gravimetric sensitivity of the BN/AlN-based acoustic waveguides was then calculated for both the AMs and elliptically polarized S0 modes; the AM-based sensor velocity and attenuation shifts due to the viscosity of a surrounding liquid was theoretically predicted. The performed investigation suggests that wz-BN/AlN is a very promising substrate material suitable for developing GHz band devices with enhanced electroacoustic coupling efficiency and suitable for application in telecommunications and sensing fields. PMID:25625904

  12. Analytical study of the propagation of fast longitudinal modes along wz-BN/AlN thin acoustic waveguides.

    PubMed

    Caliendo, Cinzia

    2015-01-23

    The propagation of the fundamental symmetric Lamb mode S0 along wz-BN/AlN thin composite plates suitable for telecommunication and sensing applications is studied. The investigation of the acoustic field profile across the plate thickness revealed the presence of modes having longitudinal polarization, the Anisimkin Jr. plate modes (AMs), travelling at a phase velocity close to that of the wz-BN longitudinal bulk acoustic wave propagating in the same direction. The study of the S0 mode phase velocity and coupling coefficient (K2) dispersion curves, for different electrical boundary conditions, has shown that eight different coupling configurations are allowable that exhibit a K2 as high as about 4% and very high phase velocity (up to about 16,700 m/s). The effect of the thickness and material type of the metal floating electrode on the K2 dispersion curves has also been investigated, specifically addressing the design of an enhanced coupling device. The gravimetric sensitivity of the BN/AlN-based acoustic waveguides was then calculated for both the AMs and elliptically polarized S0 modes; the AM-based sensor velocity and attenuation shifts due to the viscosity of a surrounding liquid was theoretically predicted. The performed investigation suggests that wz-BN/AlN is a very promising substrate material suitable for developing GHz band devices with enhanced electroacoustic coupling efficiency and suitable for application in telecommunications and sensing fields.

  13. Observation, control, and modal analysis of longitudinal coupled-bunch instabilities in the ALS via a digital feedback system

    SciTech Connect

    Fox, J.D.; Claus, R.; Hindi, H.; Linscott, I.; Prabhakar, S.; Ross, W.; Teytelman, D.; Drago, A.; Serio, M.; Byrd, J.; Corlett, J.; Stover, G.

    1997-01-01

    The operation of a longitudinal multibunch damping system using digital signal processing (DSP) techniques is shown via measurements from the Lawrence Berkeley Laboratory (LBL) Advanced Light Source (ALS). The feedback system (developed for use by PEP-II, ALS, and DA{Phi}NE) uses a parallel array of signal processors to implement a bunch-by-bunch feedback system for sampling rates up to 500 MHz. The programmable DSP system allows feedback control as well as accelerator diagnostics. A diagnostic technique is illustrated which uses the DSP system to excite and then damp the beam. The resulting 12-ms time domain transient is Fourier analyzed to provide the simultaneous measurement of growth rates and damping rates of all unstable coupled-bunch beam modes. {copyright} {ital 1997 American Institute of Physics.}

  14. Observation, control and modal analysis of longitudinal coupled-bunch instabilities in the ALS via a digital feedback system

    SciTech Connect

    Fox, J.D.; Claus, R.; Hindi, H.

    1996-09-01

    The operation of a longitudinal multi-bunch damping system using digital signal processing techniques is shown via measurements from the LBL Advanced Light Source. The feedback system (developed for use by PEP-II, ALS and DA{Phi}NE) uses a parallel array of signal processors to implement a bunch by bunch feedback system for sampling rates up to 500 MHz. The programmable DSP system allows feedback control as well as accelerator diagnostics. A diagnostic technique is illustrated which uses the DSP system to excite and then damp the beam. The resulting 12 ms time domain transient is Fourier analyzed to provide the simultaneous measurement of growth rates and damping rates of all unstable coupled-bunch beam modes.

  15. Hypnosis-based psychodynamic treatment in ALS: a longitudinal study on patients and their caregivers

    PubMed Central

    Kleinbub, Johann R.; Palmieri, Arianna; Broggio, Alice; Pagnini, Francesco; Benelli, Enrico; Sambin, Marco; Sorarù, Gianni

    2015-01-01

    Background: Evidence of psychological treatment efficacy is strongly needed in ALS, particularly regarding long-term effects. Methods: Fifteen patients participated in a hypnosis treatment and self-hypnosis training protocol after an in-depth psychological and neurological evaluation. Patients' primary caregivers and 15 one-by-one matched control patients were considered in the study. Measurements of anxiety, depression and quality of life (QoL) were collected at the baseline, post-treatment, and after 3 and 6 months from the intervention. Bayesian linear mixed-models were used to evaluate the impact of treatment and defense style on patients' anxiety, depression, QoL, and functional impairment (ALSFRS-r), as well as on caregivers' anxiety and depression. Results: The statistical analyses revealed an improvement in psychological variables' scores immediately after the treatment. Amelioration in patients' and caregivers' anxiety as well as caregivers' depression, were found to persist at 3 and 6 months follow-ups. The observed massive use of primitive defense mechanisms was found to have a reliable and constant buffer effect on psychopathological symptoms in both patients and caregivers. Notably, treated patients decline in ALSFRS-r score was observed to be slower than that of control group's patients. Discussion: Our brief psychodynamic hypnosis-based treatment showed efficacy both at psychological and physical levels in patients with ALS, and was indirectly associated to long-lasting benefits in caregivers. The implications of peculiar psychodynamic factors and mind-body techniques are discussed. Future directions should be oriented toward a convergence of our results and further psychological interventions, in order to delineate clinical best practices for ALS. PMID:26136710

  16. Lasing and Longitudinal Cavity Modes in Photo-Pumped Deep Ultraviolet AlGaN Heterostructures

    DTIC Science & Technology

    2013-04-29

    density of 84kW/cm2 suggests that the electrically pumped sub-300 nm ultraviolet laser diodes are imminent.VC 2013 AIP Publishing LLC. REPORT...threshold pumping density of 84 kW/cm2 suggests that the electrically pumped sub-300 nm ultraviolet laser diodes are imminent. VC 2013 AIP Publishing LLC...http://dx.doi.org/10.1063/1.4803689] During the last two decades, AlInGaN-based light emit- ting diode (LED) and laser diode (LD) technology has

  17. INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Line width of a single longitudinal mode emitted by an AlGaAs heterojunction laser

    NASA Astrophysics Data System (ADS)

    Bogatov, Alexandr P.; Eliseev, P. G.; Luk'yanov, S. A.; Pak, G. T.; Petrakova, T. V.

    1988-11-01

    A nonmonotonic dependence of the emission line width on the power was observed for a single longitudinal mode of an AlGaAs heterojunction laser. This behavior could be due to the dependence of the waveguide coefficient of the amplitude-phase coupling on the nature of operation of the laser.

  18. Longitudinal study on potential neurotoxic effects of aluminium: II. Assessment of exposure and neurobehavioral performance of Al welders in the automobile industry over 4 years.

    PubMed

    Kiesswetter, Ernst; Schäper, M; Buchta, M; Schaller, K H; Rossbach, B; Kraus, T; Letzel, S

    2009-11-01

    This is the second of two parallel longitudinal studies investigating Al exposure and neurobehavioral health of Al welders over 4 years. While the first published study in the trail and truck construction industry examined the neurobehavioral development of Al welders from age 41-45 in the group mean (Kiesswetter et al. in Int Arch Occup Environ Health 81:41-67, 2007), the present study in the automobile industry followed the development from 35 to 39. Although no conspicuous neurobehavioral developments were detected in the first study, which furthermore exhibited the higher exposure, it cannot be excluded that exposure effects appear in earlier life and exposure stages. The longitudinal study is based on a repeated measurement design comprising 4 years with three measurements in 2 years intervals. 92 male Al welders in the automobile industry were compared with 50 non-exposed construction workers of the same industry and of similar age. The repeated measurements included total dust in air, and Al pre- and post-shift plasma and urine samples. Neurobehavioral methods comprised symptoms, verbal intelligence, logic thinking, psychomotor behavior, memory, and attention. The computer aided tests came from the Motor Performance Series and the European Neurobehavioral Evaluation System. The courses of neurobehavioral changes were analyzed with multivariate covariance-analytical methods considering the covariates age, indicators of 'a priori' intelligence differences (education or markers of 'premorbid' intelligence), and alcohol consumption (carbohydrate-deficient transferrin in plasma). Additionally, the interrelationship, reliability and validity of biomonitoring measures were examined. The mean environmental dust load during welding, 0.5-0.8 mg/m(3), and the mean internal load of the welders (pre-shift: 23-43 microg Al/g creatinine in urine; 5-9 microg Al/l plasma) were significantly lower than in the parallel study. Under low exposure, the stability of biomonitoring

  19. [Al

    PubMed

    Purath; Köppe; Schnöckel

    1999-10-04

    A "naked" aluminum atom links two aluminum tetrahedra in the [Al(7){N(SiMe(3))(2)}(6)](-) ion (see picture), which results from the reaction of a metastable AlCl solution with LiN(SiMe(3))(2) and crystallizes with [Li(OEt(2))(3)](+) as cation. This unique structure among molecular metal atom clusters represents a small but characteristic section of cubic close-packed aluminum.

  20. Management of outpatients in France with stable coronary artery disease. Findings from the prospeCtive observational LongitudinAl RegIstry oF patients with stable coronary arterY disease (CLARIFY) registry.

    PubMed

    Danchin, Nicolas; Ferrieres, Jean; Guenoun, Maxime; Cattan, Simon; Rushton-Smith, Sophie K; Greenlaw, Nicola; Ferrari, Roberto; Steg, Philippe Gabriel

    2014-01-01

    Improvements in the treatment of coronary artery disease mean that an increasing number of patients survive acute cardiovascular events and live as outpatients with or without anginal symptoms. To determine the characteristics and management of contemporary outpatients with stable coronary artery disease in Western Europe, and to compare France with the other Western European countries. CLARIFY (prospeCtive observational LongitudinAl RegIstry oF patients with stable coronary arterY disease) is an international, prospective, observational, longitudinal study. Between November 2009 and July 2010, 32,954 adult outpatients with stable coronary artery disease (defined as a history of documented myocardial infarction [of >3 months], prior coronary revascularization, chest pain with myocardial ischaemia, or coronary stenosis of>50% proven by angiography) were enrolled in 45 countries. The demographics and management of CLARIFY patients enrolled in France were compared with those enrolled in other Western European countries (Austria, Belgium, Denmark, Germany, Greece, Ireland, Italy, Netherlands, Portugal, Spain, Switzerland and the UK). Of the 14,726 patients enrolled in Western Europe (mean age 66.2 [10.2] years; 79.6% male), 2432 (16.5%) were from France. The use of aspirin was lower in France than in other Western European countries (74.5% vs. 86.9%, respectively), whereas use of thienopyridines (48.5% vs. 21.7%), oral anticoagulants (12.3% vs. 9.0%) and lipid-lowering drugs (95.8% vs. 92.5%) was higher. Beta-blockers were used in 73% of both groups. Angina was less prevalent in France (6.3% vs. 15.5%) and French patients showed higher levels of physical activity than their counterparts in Western Europe. The management of patients with stable CAD in France appears favourable, with good adherence to guideline-based therapies, but there remains room for improvement in terms of symptom and risk factor control. Copyright © 2014. Published by Elsevier Masson SAS.

  1. Longitudinal study on potential neurotoxic effects of aluminium: I. Assessment of exposure and neurobehavioural performance of Al welders in the train and truck construction industry over 4 years.

    PubMed

    Kiesswetter, E; Schäper, M; Buchta, M; Schaller, K H; Rossbach, B; Scherhag, H; Zschiesche, W; Letzel, S

    2007-10-01

    Previous cross sectional studies on potential neurotoxic effects of long-term aluminium exposures by aluminium welders lack clear interpretable results for methodological reasons. The present longitudinal study examined on the one hand the reliability and representativity of Al-biomonitoring as indicator of individual long-term exposure and on the other hand the long-term changes of neurobehavioural performance in Al welders in relation to Al exposure and neurobehavioural performance changes of a non-exposed control group. The longitudinal study compared repeatedly measured exposure data and neurobehavioural data of 20, initially 44, male Al welders in the train and truck construction industry with data of a control group of similar age on the basis of three investigations over a period of 4 years. The repeated measurements of exposure included total dust in air as well as Al in pre- and post-shift plasma and urine samples. Neurobehavioural methods comprised symptoms, verbal intelligence, logic thinking, psychomotor behaviour, memory, and attention. Computer-aided tests from the Motor Performance Series (MLS) and the European Neurobehavioural Evaluation System (EURO-NES) were used. The characteristics of the biomonitoring data and the relationship to neurobehavioural data were examined with methods of correlation and regression analysis. The courses of neurobehavioural changes were analysed with multivariate covariance-analytical methods (MANCOVA) considering the covariates age, indicators of 'a priori' intelligence differences (education or 'premorbid' intelligence), and alcohol consumption (carbohydrate-deficient transferrin in plasma, CDT). The mean total dust load during welding, near to the routinely worn ventilated helmets, was in the range of 5-8 mg/m(3). The biomonitoring data of the welders (pre-shift: 88-140 microg Al/g creatinine in urine; 13-16 microg Al/l plasma) showed a high long-term stability but also sensitivity to acute shift dependent exposure

  2. Nothing Matters?: A Critique of the Ramirez, et al. Longitudinal Study of Instructional Programs for Language-Minority Children.

    ERIC Educational Resources Information Center

    Rossell, Christine H.

    1992-01-01

    Critiques the Ramirez et al. study of bilingual programs for its serious research flaws. Calls into question the findings of no consistent difference in the achievement of language-minority children regardless of how much Spanish or English is used in instruction. Proposes a reanalysis of the Ramirez data. (KS)

  3. VXI based multibunch detector and QPSK modulator for the PEP-II/ALS/DA{Phi}NE longitudinal feedback system

    SciTech Connect

    Young, A.; Fox, J.; Teytelman, D.

    1997-04-01

    The PEP-II/ALS/DA{Phi}NE feedback systems are complex systems implemented using analog, digital and microwave circuits. The VXI hardware implementation for the Front-end and Back-end analog processing modules is presented. The Front-end module produces a baseband beam phase signal from pickups using a microwave tone burst generator. The Back-end VXI module generates an AM/QPSK modulated signal from a baseband correction signal computed in a digital signal processor. These components are implemented in VXI packages that allow a wide spectrum of system functions including a 120 MHz bandwidth rms detector, reference phase servo, woofer link to the RF control system, standard VXI status/control, and user defined registers. The details of the design and implementation of the VXI modules including performance characteristics are presented.

  4. Template-free fabrication of Ag nanowire arrays/Al2O3 assembly with flexible collective longitudinal-mode resonance and ultrafast nonlinear optical response

    NASA Astrophysics Data System (ADS)

    Hui, Shuai; Gao, Junhua; Wu, Xingzhi; Li, Zhongguo; Zou, Yousheng; Song, Yinglin; Cao, Hongtao

    2016-06-01

    We utilized a co-sputtering technique without any templates, featuring growing and etching synchronously, to delicately fabricate dense and ultrafine Ag nanowire arrays/alumina matrix composite films. Both the diameter and separation distance of the Ag nanowire arrays in the composites are not only within the scope of sub-10 nm but also tunable, which is very hard to accomplish for the conventional optical lithography- or template-based method. It is exhibited that the collective longitudinal plasmon resonance of the composite films, covering a wide range from visible to the near infrared region, is extremely sensitive to the geometrical parameters of the Ag nanowires, owing to the strong plasmonic coupling among neighboring nanowires. The experimental observations were also theoretically supported by the near-field electromagnetic numerical simulation. More interestingly, the fabricated composite films demonstrated ultrafast nonlinear optical response in the visible light region under femtosecond laser excitation, possessing a short relaxation time of 1.45 ps for the longitudinal mode (L mode) resonance. These results indicate that the proposed composite films as a building block with exotic optical properties could provide an opportunity to construct integrated nanodevices for plasmonic optical applications.

  5. "Does anger regulation mediate the discrimination-mental health link among Mexican-origin adolescents? A longitudinal mediation analysis using multilevel modeling": Correction to Park et al. (2016).

    PubMed

    2017-02-01

    Reports an error in "Does Anger Regulation Mediate the Discrimination-Mental Health Link Among Mexican-Origin Adolescents? A Longitudinal Mediation Analysis Using Multilevel Modeling" by Irene J. K. Park, Lijuan Wang, David R. Williams and Margarita Alegría (Developmental Psychology, Advanced Online Publication, Nov 28, 2016, np). In the article, there were several typographical errors in the Recruitment and Procedures section. The percentage of mothers who responded to survey items should have been 99.3%. Additionally, the youths surveyed at T2 and T3 should have been n=246 . Accordingly, the percentage of youths surveyed in T2 and T3 should have been 91.4% and the percentage of mothers surveyed at T2 and T3 should have been 90.7%. Finally, the youths missing at T2 should have been n= 23, and therefore the attrition rate for youth participants should have been 8.6. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2016-57671-001.) Although prior research has consistently documented the association between racial/ethnic discrimination and poor mental health outcomes, the mechanisms that underlie this link are still unclear. The present 3-wave longitudinal study tested the mediating role of anger regulation in the discrimination-mental health link among 269 Mexican-origin adolescents (Mage = 14.1 years, SD = 1.6; 57% girls), 12 to 17 years old. Three competing anger regulation variables were tested as potential mediators: outward anger expression, anger suppression, and anger control. Longitudinal mediation analyses were conducted using multilevel modeling that disaggregated within-person effects from between-person effects. Results indicated that outward anger expression was a significant mediator; anger suppression and anger control were not significant mediators. Within a given individual, greater racial/ethnic discrimination was associated with more frequent outward anger expression. In turn

  6. Measurement of the parity-violating longitudinal single-spin asymmetry AL for W - (+) boson production in polarized proton collisions at √{ s} = 510 GeV at RHIC

    NASA Astrophysics Data System (ADS)

    Surrow, Bernd; STAR Collaboration

    2016-09-01

    The STAR experiment at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is carrying out a spin physics program in high-energy polarized proton collisions to gain a deeper insight into the spin structure and dynamics of the proton. The collision of polarized protons at √{ s} = 500GeV opened a new era of spin-flavor structure studies using the production of W - (+) bosons which are primarily produced in u + d (d + u) collisions. The STAR experiment is well equipped to measure W - (+) ->e- +νe (e+ +νe) in longitudinally polarized proton collisions. The published STAR AL results (combination of 2011 and 2012 data) have been used by two global analyses groups suggesting a significant impact in constraining the helicity distributions of anti- u and anti- d quarks. In 2013, the STAR experiment collected a data set at √{ s} = 510 GeV with a factor of three larger figure of merit based on a total integrated luminosity of 300 pb-1 and an average beam polarization of 54 % . We will report on the status of the STAR 2013 W AL analysis along with future plans.

  7. Longitudinally Graded Optical Fibers

    NASA Astrophysics Data System (ADS)

    Evert, Alexander George

    hexahydrate and 0.30 M Al 3 derived from aluminum chloride hexahydrate. The doped preform was engineered to have two core layers of differing chemical composition, resulting in both a gradient refractive index profile as well as a gradient acoustic profile. While exhibiting higher loss than the original LGF, the Yb 3-doped fiber showed slightly better SBS suppression with preliminary calculations showing at least 6 dB reduction in Brillouin gain. Lastly, reported here is a straight-forward and flexible method to fabricate silica optical fibers of circular cladding cross-section and rectilinear cores whose aspect ratio and refractive index profile changes with position along the fiber in a deterministic way. Specifically, a modification to the process developed to produce longitudinally-graded optical fibers, was employed. Herein reported are MCVD-derived germanosilicate fibers with rectangular cores where the aspect ratio changes by nearly 200 % and the average refractive index changed by about 5 %. Fiber losses were measured to be about 50 dB/km. Such rectangular core fibers are useful for a variety of telecommunication and biomedical applications and the dimensional and optical chirp provides a deterministic way to control further the modal properties of the fiber. Possible applications of longitudinally graded optical fibers and future improvements are also discussed. The methods employed are very straight-forward and technically simple, providing for a wide variety of longitudinal refractive index and acoustic velocity profiles, as well as core shapes, that could be especially valuable for SBS suppression in high energy laser systems. Next generation analogs, with longitudinally-graded compositional profiles that are very reasonable to fabricate, are shown computationally to be more effective at suppressing SBS than present alternatives, such as externally-applied temperature or strain gradients.

  8. Titan's Longitudinal Dunes in the Lab.

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

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

  9. Diagnosing ALS

    MedlinePlus

    ... that a person diagnosed with ALS seek a second opinion from an ALS "expert" - someone who diagnoses and treats many ALS patients and has training in this medical specialty. The ALS Association maintains a list of recognized experts in the field of ALS. See ALS Association Certified Centers of ...

  10. ALS Association

    MedlinePlus

    ... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

  11. Longitudinal impedance of RHIC

    SciTech Connect

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

    2015-05-03

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

  12. Longitudinal Multistage Testing

    ERIC Educational Resources Information Center

    Pohl, Steffi

    2013-01-01

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

  13. Longitudinal Stability Calculations

    SciTech Connect

    Blaskiewicz,M.

    2009-01-02

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

  14. Predictors of Transfer Adjustment: A Longitudinal Study.

    DTIC Science & Technology

    1985-01-01

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

  15. Longitudinal Magnification Drawing Mistake

    NASA Astrophysics Data System (ADS)

    Rabal, Héctor; Cap, Nelly; Trivi, Marcelo

    2004-01-01

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

  16. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- www.mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) ...

  17. Longitudinal magnetoresistance of potassium

    NASA Astrophysics Data System (ADS)

    Huberman, M. L.

    1987-06-01

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

  18. Longitudinal Functional Data Analysis.

    PubMed

    Park, So Young; Staicu, Ana-Maria

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

  19. GATB LONGITUDINAL MATURATION STUDY.

    ERIC Educational Resources Information Center

    DROEGE, ROBERT C.

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

  20. Longitudinal discharge laser baffles

    DOEpatents

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

    1994-06-07

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

  1. Longitudinal discharge laser electrodes

    DOEpatents

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

    1994-08-23

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

  2. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

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

  3. Longitudinal discharge laser electrodes

    DOEpatents

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

    1994-01-01

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

  4. Longitudinally graded optical fibers

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  5. Longitudinal multiple sclerosis lesion segmentation data resource.

    PubMed

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

    2017-06-01

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

  6. Experimental Demonstration of Longitudinal Magnification

    ERIC Educational Resources Information Center

    Razpet, Nada; Susman, Katarina; Cepic, Mojca

    2009-01-01

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

  7. Experimental Demonstration of Longitudinal Magnification

    ERIC Educational Resources Information Center

    Razpet, Nada; Susman, Katarina; Cepic, Mojca

    2009-01-01

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

  8. Muon cooling: longitudinal compression.

    PubMed

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

    2014-06-06

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

  9. Concurrent and Longitudinal Predictors of Calculation Skills in Preschoolers

    ERIC Educational Resources Information Center

    Tobia, Valentina; Bonifacci, Paola; Marzocchi, Gian Marco

    2016-01-01

    Early calculation abilities in preschoolers are predictive of mathematics achievement in subsequent grades (e.g., Jordan et al. 2009). Two studies were conducted to evaluate concurrent and longitudinal predictors of early calculation skills. In the first study, 102 preschoolers (57.8% female; mean age?=?60.57?±?8.66 months) were given vocabulary,…

  10. Concurrent and Longitudinal Predictors of Calculation Skills in Preschoolers

    ERIC Educational Resources Information Center

    Tobia, Valentina; Bonifacci, Paola; Marzocchi, Gian Marco

    2016-01-01

    Early calculation abilities in preschoolers are predictive of mathematics achievement in subsequent grades (e.g., Jordan et al. 2009). Two studies were conducted to evaluate concurrent and longitudinal predictors of early calculation skills. In the first study, 102 preschoolers (57.8% female; mean age?=?60.57?±?8.66 months) were given vocabulary,…

  11. PREPROCESSING MAGNETIC FIELDS WITH CHROMOSPHERIC LONGITUDINAL FIELDS

    SciTech Connect

    Yamamoto, Tetsuya T.; Kusano, K.

    2012-06-20

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

  12. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  13. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  14. A Large, Longitudinal Dune

    NASA Image and Video Library

    2015-02-11

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

  15. Modeling nonstationary longitudinal data.

    PubMed

    Núñez-Antón, V; Zimmerman, D L

    2000-09-01

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

  16. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  17. Longitudinal Stern-Gerlach

    NASA Astrophysics Data System (ADS)

    Higinbotham, Douglas

    2006-11-01

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

  18. Digital Longitudinal Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Rimkus, Daniel Steven

    1985-12-01

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

  19. Longitudinal space charge amplifier

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  20. Current status of longitudinal stability

    NASA Technical Reports Server (NTRS)

    Donlan, Charles J

    1948-01-01

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

  1. Morphology of AlN whiskers grown by reacting N2 gas and Al vapor

    NASA Astrophysics Data System (ADS)

    Matsumoto, M.; Saitou, H.; Takeuchi, Y.; Harada, S.; Tagawa, M.; Ujihara, T.

    2017-06-01

    We have investigated the morphology of AlN whiskers on a polycrystalline AlN substrate by using Fe-Al alloy melts under the different synthesis conditions. Formation density of the AlN whiskers increases and the diameter of the whisker decreases with increasing Al content of the Fe-Al alloy melt. Most of the AlN whiskers were zigzag shape with the hexagonal cross section. The longitudinal direction was the [0001] direction. The facet with the zigzag shape was the {1 1 bar 01} or {1 1 bar 0 1 bar } pyramidal plane and the period of the zigzag facet was almost constant. The average diameter of the whiskers and the period of the zigzag facet decrease with increasing Al content. At the initial stage of the whisker formation, the island of AlN formed on the AlN substrate and the pyramidal facet grows via step-flow growth. From the observation, we discussed the possible mechanism for the formation of the zigzag-shape AlN whiskers.

  2. AlGaAs transverse junction stripe laser with distributed Bragg reflector

    NASA Astrophysics Data System (ADS)

    Kawanishi, H.; Hafich, M.; Lenz, B.; Peterson, P.

    1980-09-01

    A semiclosed Zn diffusion process was used to fabricate a new longitudinal mode stabilized AlGaAs transverse junction stripe laser with distributed Bragg reflector. The laser is capable of stabilized single longitudinal mode operation and could be incorporated in a planar monolithic integrated optical circuit. The temperature dependence of the lasing wavelength was 0.5 A/deg C.

  3. Longitudinal dynamics in storage rings

    SciTech Connect

    Colton, E.P.

    1986-01-01

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

  4. Longitudinal motion in circular accelerators

    SciTech Connect

    Cole, F.T.

    1985-01-01

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

  5. The LBL Advanced Light Source (ALS) transverse coupled-bunch feedback system: Recent commissioning results

    SciTech Connect

    Barry, W.; Byrd, J.; Corlett, J.

    1994-10-01

    The ALS transverse coupled-bunch feedback system is described along with some recent commissioning results. Results presented include transfer function measurements, demonstrations of multi-bunch damping, and demonstrations of simultaneous transverse and longitudinal systems operation.

  6. Longitudinal confinement and matching of an intense electron beam

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

  7. Longitudinal confinement and matching of an intense electron beam

    SciTech Connect

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

    2011-01-15

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

  8. Hemorrhagic Longitudinally Extensive Transverse Myelitis.

    PubMed

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

    2016-01-01

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

  9. Longitudinal Studies of Spelling Development.

    ERIC Educational Resources Information Center

    Ellis, Nick

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

  10. Students dance longitudinal standing waves

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.

    2017-05-01

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

  11. Regression Splines with Longitudinal Data

    USDA-ARS?s Scientific Manuscript database

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

  12. Abu al-Layth al-Libi

    DTIC Science & Technology

    2015-02-01

    jihadi doctrine, al-Libi enrolled himself in the recently erected and highly popular al-Faruq 2 “Al-Sahab Releases ‘Winds of Paradise , Part III...February 2008, http://news.bbc.co.uk/2/hi/south_asia/7220823.stm. 3 “Al-Sahab Releases ‘Winds of Paradise , Part III,’” Global Terrorism Research Project...5 “Al-Sahab Releases ‘Winds of Paradise , Part III,’” Global Terrorism Research Project. 6 Ibid. The date provided in the video is 1410

  13. What Is ALS?

    MedlinePlus

    ... Javits, actor David Niven, “Sesame Street” creator Jon Stone, boxing champion Ezzard Charles, NBA Hall of Fame ... Help for People with ALS and Caregivers Read stories from families living with ALS Forms of ALS ...

  14. Baseline patient characteristics and mortality associated with longitudinal intervention compliance.

    PubMed

    Lin, Julia Y; Ten Have, Thomas R; Bogner, Hillary R; Elliott, Michael R

    2007-12-10

    Lin et al. (http://www.biostatsresearch.com/upennbiostat/papers/, 2006) proposed a nested Markov compliance class model in the Imbens and Rubin compliance class model framework to account for time-varying subject noncompliance in longitudinal randomized intervention studies. We use superclasses, or latent compliance class principal strata, to describe longitudinal compliance patterns, and time-varying compliance classes are assumed to depend on the history of compliance. In this paper, we search for good subject-level baseline predictors of these superclasses and also examine the relationship between these superclasses and all-cause mortality. Since the superclasses are completely latent in all subjects, we utilize multiple imputation techniques to draw inferences. We apply this approach to a randomized intervention study for elderly primary care patients with depression.

  15. The longitudinal cerebrospinal fluid metabolomic profile of amyotrophic lateral sclerosis

    PubMed Central

    Gray, Elizabeth; Larkin, James R.; Claridge, Tim D. W.; Talbot, Kevin; Sibson, Nicola R.; Turner, Martin R.

    2015-01-01

    Neurochemical biomarkers are urgently sought in ALS. Metabolomic analysis of cerebrospinal fluid (CSF) using proton nuclear magnetic resonance (1H-NMR) spectroscopy is a highly sensitive method capable of revealing nervous system cellular pathology. The 1H-NMR CSF metabolomic signature of ALS was sought in a longitudinal cohort. Six-monthly serial collection was performed in ALS patients across a range of clinical sub-types (n = 41) for up to two years, and in healthy controls at a single time-point (n = 14). A multivariate statistical approach, partial least squares discriminant analysis, was used to determine differences between the NMR spectra from patients and controls. Significantly predictive models were found using those patients with at least one year's interval between recruitment and the second sample. Glucose, lactate, citric acid and, unexpectedly, ethanol were the discriminating metabolites elevated in ALS. It is concluded that 1H-NMR captured the CSF metabolomic signature associated with derangements in cellular energy utilization connected with ALS, and was most prominent in comparisons using patients with longer disease duration. The specific metabolites identified support the concept of a hypercatabolic state, possibly involving mitochondrial dysfunction specifically. Endogenous ethanol in the CSF may be an unrecognized novel marker of neuronal tissue injury in ALS. PMID:26121274

  16. LONGITUDINAL LASER WIRE AT SNS

    SciTech Connect

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

    2014-01-01

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

  17. The Importance of Longitudinal Studies

    NASA Astrophysics Data System (ADS)

    Knezek, Patricia

    2014-01-01

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

  18. Longitudinal normals for piezoelectric elastic media

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

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

  19. Analytical estimate of phase mixing time of longitudinal Akhiezer-Polovin waves

    NASA Astrophysics Data System (ADS)

    Mukherjee, Arghya; Sengupta, Sudip

    2014-11-01

    Phase mixing of a longitudinal Akhiezer-Polovin wave subjected to a small amplitude longitudinal perturbation and its eventual breaking is studied analytically. It is well known that longitudinal Akhiezer-Polovin wave subjected to arbitrarily small longitudinal perturbation breaks via the process of phase mixing at an amplitude well below its limiting amplitude [Verma et al., Phys. Rev. Lett. 108, 125005 (2012)]. We analytically show that the phase mixing time (breaking time, ωpτmix) scales with β (phase velocity) and um(maximum fluid velocity) as ωpτmi x˜2/πβ 3 δ [1 /um2-1 /4 ] , where δ is the amplitude of velocity perturbation and ωp is the non-relativistic plasma frequency. This analytical dependence of phase mixing time on β, um, and δ is further verified using numerical simulations based on Dawson sheet model.

  20. Hemorrhagic Longitudinally Extensive Transverse Myelitis

    PubMed Central

    Wu, Chris Y.; Riangwiwat, Tanawan

    2016-01-01

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

  1. Longitudinal bulk acoustic mass sensor

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  2. Longitudinal bulk acoustic mass sensor

    SciTech Connect

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

    2009-07-20

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

  3. Parameterized Linear Longitudinal Airship Model

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  4. Development of a longitudinal density monitor for storage rings

    SciTech Connect

    Zolotorev, M.; Beche, J.-F.; Byrd, J.; Datte, P.; De Santis, S.; Denes, P.; Placidi, M.; Ratti, A.; Riot, V.; Schoenlein, R.; Turner, W.

    2003-05-28

    We report on development of a new storage ring operations tool for measurement of longitudinal beam density profile. The technique mixes synchrotron light with light from a mode locked solid-state laser oscillator in a non-linear crystal and detects the up-converted radiation with a photo-multiplier. The laser is phase locked to the storage ring RF system. The laser choices available for repetition frequency, pulse length and phase modulation give a very wide range of options for matching the bunch configuration of particular storage rings. Progress in the technology of solid-state lasers ensures this system can be made robust for routine use in storage ring operations. A very large number of important applications are possible including measurement of the fraction of untrapped particles prior to acceleration, the population of particles in the nominally unfilled RF buckets in a bunch train (''ghost bunches''), longitudinal tails, the diffusion of particles into the beam abort gap and th e normal bunch parameters of longitudinal shape and intensity. We are currently investigating application to two devices: (1) the 1.9 GeV ALS electron storage ring at LBNL with 328 RF buckets, 2ns bucket spacing, 276 nominally filled bunches, 15-30ps rms bunch length and (2) the 7 TeV LHC proton collider under construction at CERN with 35,640 RF buckets, 2.5 ns bucket spacing, 2,808 nominally filled bunches, 280-620 ps rms bunch length. A proof of principle experiment is being conducted on ALS. The results of the ALS experiment and detailed analyses of the application to LHC and its requirements are described.

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

    ERIC Educational Resources Information Center

    Polat, Brittany; Kim, Youjin

    2014-01-01

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

  6. Magnetic field dependence of the longitudinal and transverse spin correlation in the Blume-Hubbard theory

    NASA Technical Reports Server (NTRS)

    Sung, C. C.

    1973-01-01

    The longitudinal and transverse spin-correlation functions of local paramagnetic impurities are solved in the long-time limit on the basis of the Blume-Hubbard theory. The magnetic field dependence of the nuclear spin-lattice relaxation via paramagnetic centers is in good agreement with the experimental data by McHenry et al.

  7. A Longitudinal Study of Receptive Vocabulary Breadth Knowledge Growth and Vocabulary Fluency Development

    ERIC Educational Resources Information Center

    Zhang, Xian; Lu, Xiaofei

    2014-01-01

    This article reports results of a longitudinal study of vocabulary breadth knowledge growth, vocabulary fluency development, and the relationship between the two. We administered two versions of the Vocabulary Levels Test (VLT; Nation 1983; Nation 1990; Schmitt et al. 2001) to 300 students at a Chinese university at three different time points…

  8. A Longitudinal Study of Receptive Vocabulary Breadth Knowledge Growth and Vocabulary Fluency Development

    ERIC Educational Resources Information Center

    Zhang, Xian; Lu, Xiaofei

    2014-01-01

    This article reports results of a longitudinal study of vocabulary breadth knowledge growth, vocabulary fluency development, and the relationship between the two. We administered two versions of the Vocabulary Levels Test (VLT; Nation 1983; Nation 1990; Schmitt et al. 2001) to 300 students at a Chinese university at three different time points…

  9. TRANSVERSE OSCILLATIONS OF A LONGITUDINALLY STRATIFIED CORONAL LOOP SYSTEM

    SciTech Connect

    Fathalian, N.; Safari, H. E-mail: safari@znu.ac.i

    2010-11-20

    Collective transverse coronal loop oscillations seem to be detected in observational studies. In this regard, Luna et al. modeled the collective kink-like normal modes of several cylindrical loop systems using the T-matrix theory. This paper investigates the effects of longitudinal density stratification along the loop axis on the collective kink-like modes of the system of coronal loops. The coronal loop system is modeled as cylinders of parallel flux tubes, with two ends of each loop at the dense photosphere. The flux tubes are considered as uniform magnetic fields, with stratified density along the loop axis which changes discontinuously at the lateral surface of each cylinder. The MHD equations are reduced to solve a set of two coupled dispersion relations for frequencies and wavenumbers, in the presence of a stratification parameter. The fundamental and first overtone frequencies and longitudinal wavenumbers are computed. The previous results are verified for an unstratified coronal loop system. Finally, we conclude that an increased longitudinal density stratification parameter will result in an increase of the frequencies. The frequency ratios, first overtones to fundamentals, are very sensitive functions of the density scale height parameter. Therefore, stratification should be included in dynamics of coronal loop systems. For unstratified coronal loop systems, these ratios are the same as monoloop ones.

  10. Marital quality, forgiveness, empathy, and rumination: a longitudinal analysis.

    PubMed

    Paleari, F Giorgia; Regalia, Camillo; Fincham, Frank

    2005-03-01

    McCullough, Rachal, et al.'s (1998) social-psychological framework of forgiveness informed a longitudinal study that examined the extent to which marital forgiveness is determined by social-cognitive (the offended spouse's rumination and emotional empathy) and relationship variables (the quality of the relationship in which the offense took place). In the study, 119 husbands and 124 wives from long- and medium-term marriages in north Italy provided data at two time points separated by a 6-month interval. Structural equation models showed that rumination and empathy independently predicted concurrent marital forgiveness. Forgiveness in turn predicted concurrent marital quality. Finally, reciprocal directions of effect emerged between forgiveness and marital quality over time. These results are discussed in terms of their implications for promoting forgiveness, and future research directions are outlined.

  11. Longitudinal Control of Intense Charged Particle Beams

    DTIC Science & Technology

    2011-01-01

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

  12. /Cu-Al System

    NASA Astrophysics Data System (ADS)

    Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum

    2014-05-01

    Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

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

    NASA Astrophysics Data System (ADS)

    Imtiaz, Ahmad; 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 Reλ 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.

  14. Longitudinal study of fingerprint recognition.

    PubMed

    Yoon, Soweon; Jain, Anil K

    2015-07-14

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

  15. Longitudinal study of fingerprint recognition

    PubMed Central

    Yoon, Soweon; Jain, Anil K.

    2015-01-01

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

  16. ALS (Amyotrophic Lateral Sclerosis)

    MedlinePlus

    ... risk factors for veterans include exposure to lead, pesticides, and other environmental toxins. ALS is recognized as ... from scientific studies suggests that both genetics and environment play a role in the development of ALS. ...

  17. Lou Gehrig's Disease (ALS)

    MedlinePlus

    ... 1930s. People in England and Australia call ALS motor neurone disease (MND). The French refer to it ... about ALS in 1869. Lou Gehrig's disease damages motor neurons in the brain and spinal cord. Motor ...

  18. GWAS with longitudinal phenotypes: performance of approximate procedures

    PubMed Central

    Sikorska, Karolina; Montazeri, Nahid Mostafavi; Uitterlinden, André; Rivadeneira, Fernando; Eilers, Paul HC; Lesaffre, Emmanuel

    2015-01-01

    Analysis of genome-wide association studies with longitudinal data using standard procedures, such as linear mixed model (LMM) fitting, leads to discouragingly long computation times. There is a need to speed up the computations significantly. In our previous work (Sikorska et al: Fast linear mixed model computations for genome-wide association studies with longitudinal data. Stat Med 2012; 32.1: 165–180), we proposed the conditional two-step (CTS) approach as a fast method providing an approximation to the P-value for the longitudinal single-nucleotide polymorphism (SNP) effect. In the first step a reduced conditional LMM is fit, omitting all the SNP terms. In the second step, the estimated random slopes are regressed on SNPs. The CTS has been applied to the bone mineral density data from the Rotterdam Study and proved to work very well even in unbalanced situations. In another article (Sikorska et al: GWAS on your notebook: fast semi-parallel linear and logistic regression for genome-wide association studies. BMC Bioinformatics 2013; 14: 166), we suggested semi-parallel computations, greatly speeding up fitting many linear regressions. Combining CTS with fast linear regression reduces the computation time from several weeks to a few minutes on a single computer. Here, we explore further the properties of the CTS both analytically and by simulations. We investigate the performance of our proposal in comparison with a related but different approach, the two-step procedure. It is analytically shown that for the balanced case, under mild assumptions, the P-value provided by the CTS is the same as from the LMM. For unbalanced data and in realistic situations, simulations show that the CTS method does not inflate the type I error rate and implies only a minimal loss of power. PMID:25712081

  19. GWAS with longitudinal phenotypes: performance of approximate procedures.

    PubMed

    Sikorska, Karolina; Montazeri, Nahid Mostafavi; Uitterlinden, André; Rivadeneira, Fernando; Eilers, Paul Hc; Lesaffre, Emmanuel

    2015-10-01

    Analysis of genome-wide association studies with longitudinal data using standard procedures, such as linear mixed model (LMM) fitting, leads to discouragingly long computation times. There is a need to speed up the computations significantly. In our previous work (Sikorska et al: Fast linear mixed model computations for genome-wide association studies with longitudinal data. Stat Med 2012; 32.1: 165-180), we proposed the conditional two-step (CTS) approach as a fast method providing an approximation to the P-value for the longitudinal single-nucleotide polymorphism (SNP) effect. In the first step a reduced conditional LMM is fit, omitting all the SNP terms. In the second step, the estimated random slopes are regressed on SNPs. The CTS has been applied to the bone mineral density data from the Rotterdam Study and proved to work very well even in unbalanced situations. In another article (Sikorska et al: GWAS on your notebook: fast semi-parallel linear and logistic regression for genome-wide association studies. BMC Bioinformatics 2013; 14: 166), we suggested semi-parallel computations, greatly speeding up fitting many linear regressions. Combining CTS with fast linear regression reduces the computation time from several weeks to a few minutes on a single computer. Here, we explore further the properties of the CTS both analytically and by simulations. We investigate the performance of our proposal in comparison with a related but different approach, the two-step procedure. It is analytically shown that for the balanced case, under mild assumptions, the P-value provided by the CTS is the same as from the LMM. For unbalanced data and in realistic situations, simulations show that the CTS method does not inflate the type I error rate and implies only a minimal loss of power.

  20. Transverse-longitudinal integrated resonator

    DOEpatents

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

    2003-03-11

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

  1. Modeling a Longitudinal Relational Research Data Systems

    ERIC Educational Resources Information Center

    Olsen, Michelle D. Hunt

    2010-01-01

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

  2. Colorado Longitudinal Twin Study of Reading Disability

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  3. Fears in Czech Adolescents: A Longitudinal Study

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  4. Fears in Czech Adolescents: A Longitudinal Study

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  5. Colorado Longitudinal Twin Study of Reading Disability

    ERIC Educational Resources Information Center

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

    2007-01-01

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

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

    ERIC Educational Resources Information Center

    Aleman, Ana M. Martinez

    2010-01-01

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

  7. Modeling a Longitudinal Relational Research Data Systems

    ERIC Educational Resources Information Center

    Olsen, Michelle D. Hunt

    2010-01-01

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

  8. Longitudinal research in child and adolescent psychiatry.

    PubMed

    Verhulst, F C; Koot, H M

    1991-05-01

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

  9. LSTGEE: longitudinal analysis of neuroimaging data

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  10. A Joint Model for Longitudinal Measurements and Survival Data in the Presence of Multiple Failure Types

    PubMed Central

    Elashoff, Robert M.; Li, Gang; Li, Ning

    2009-01-01

    Summary In this article we study a joint model for longitudinal measurements and competing risks survival data. Our joint model provides a flexible approach to handle possible nonignorable missing data in the longitudinal measurements due to dropout. It is also an extension of previous joint models with a single failure type, offering a possible way to model informatively censored events as a competing risk. Our model consists of a linear mixed effects submodel for the longitudinal outcome and a proportional cause-specific hazards frailty submodel (Prentice et al., 1978, Biometrics 34, 541-554) for the competing risks survival data, linked together by some latent random effects. We propose to obtain the maximum likelihood estimates of the parameters by an expectation maximization (EM) algorithm and estimate their standard errors using a profile likelihood method. The developed method works well in our simulation studies and is applied to a clinical trial for the scleroderma lung disease. PMID:18162112

  11. Breaking of longitudinal Akhiezer-Polovin waves.

    PubMed

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

    2012-03-23

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

  12. A longitudinal study of confabulation.

    PubMed

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

    2017-02-01

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

  13. Longitudinal Variations in Jupiter's Winds

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  14. Underemployment and depression: longitudinal relationships.

    PubMed

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

    2000-12-01

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

  15. Longitudinal oscillation of launch vehicles

    NASA Technical Reports Server (NTRS)

    Glaser, R. F.

    1973-01-01

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

  16. Genetic testing in ALS

    PubMed Central

    McLaughlin, Russell L.; Heverin, Mark; Thorpe, Owen; Abrahams, Sharon; Al-Chalabi, Ammar; Hardiman, Orla

    2017-01-01

    Objective: To determine the degree of consensus among clinicians on the clinical use of genetic testing in amyotrophic lateral sclerosis (ALS) and the factors that determine decision-making. Methods: ALS researchers worldwide were invited to participate in a detailed online survey to determine their attitudes and practices relating to genetic testing. Results: Responses from 167 clinicians from 21 different countries were analyzed. The majority of respondents (73.3%) do not consider that there is a consensus definition of familial ALS (FALS). Fifty-seven percent consider a family history of frontotemporal dementia and 48.5% the presence of a known ALS genetic mutation as sufficient for a diagnosis of FALS. Most respondents (90.2%) offer genetic testing to patients they define as having FALS and 49.4% to patients with sporadic ALS. Four main genes (SOD1, C9orf72, TARDBP, and FUS) are commonly tested. A total of 55.2% of respondents would seek genetic testing if they had personally received a diagnosis of ALS. Forty-two percent never offer presymptomatic testing to family members of patients with FALS. Responses varied between ALS specialists and nonspecialists and based on the number of new patients seen per year. Conclusions: There is a lack of consensus among clinicians as to the definition of FALS. Substantial variation exists in attitude and practices related to genetic testing of patients and presymptomatic testing of their relatives across geographic regions and between experienced specialists in ALS and nonspecialists. PMID:28159885

  17. Ventilatory Control in ALS

    PubMed Central

    Nichols, Nicole L.; Van Dyke, J.; Nashold, L.; Satriotomo, I.; Suzuki, M.; Mitchell, G.S.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease. ALS selectively causes degeneration in upper and lower (spinal) motor neurons, leading to muscle weakness, paralysis and death by ventilatory failure. Although ventilatory failure is generally the cause of death in ALS, little is known concerning the impact of this disorder on respiratory motor neurons, the consequences of respiratory motor neuron cell death, or the ability of the respiratory control system to “fight back” via mechanisms of compensatory respiratory plasticity. Here we review known effects of ALS on breathing, including possible effects on rhythm generation, respiratory motor neurons, and their target organs: the respiratory muscles. We consider evidence for spontaneous compensatory plasticity, preserving breathing well into disease progression despite dramatic loss of spinal respiratory motor neurons. Finally, we review current and potential therapeutic approaches directed toward preserving the capacity to breathe in ALS patients. PMID:23692930

  18. Bayesian regression analysis of data with random effects covariates from nonlinear longitudinal measurements

    PubMed Central

    De la Cruz, Rolando; Meza, Cristian; Arribas-Gil, Ana; Carroll, Raymond J.

    2016-01-01

    Joint models for a wide class of response variables and longitudinal measurements consist on a mixed-effects model to fit longitudinal trajectories whose random effects enter as covariates in a generalized linear model for the primary response. They provide a useful way to assess association between these two kinds of data, which in clinical studies are often collected jointly on a series of individuals and may help understanding, for instance, the mechanisms of recovery of a certain disease or the efficacy of a given therapy. When a nonlinear mixed-effects model is used to fit the longitudinal trajectories, the existing estimation strategies based on likelihood approximations have been shown to exhibit some computational efficiency problems (De la Cruz et al., 2011). In this article we consider a Bayesian estimation procedure for the joint model with a nonlinear mixed-effects model for the longitudinal data and a generalized linear model for the primary response. The proposed prior structure allows for the implementation of an MCMC sampler. Moreover, we consider that the errors in the longitudinal model may be correlated. We apply our method to the analysis of hormone levels measured at the early stages of pregnancy that can be used to predict normal versus abnormal pregnancy outcomes. We also conduct a simulation study to assess the importance of modelling correlated errors and quantify the consequences of model misspecification. PMID:27274601

  19. Joint Models for a Primary Endpoint and Multiple Longitudinal Covariate Processes

    PubMed Central

    Li, Erning; Wang, Naisyin; Wang, Nae-Yuh

    2015-01-01

    Summary Joint models are formulated to investigate the association between a primary endpoint and features of multiple longitudinal processes. In particular, the subject-specific random effects in a multivariate linear random effects model for multiple longitudinal processes are predictors in a generalized linear model for primary endpoints. Li et al. (2004, Biometrics 60, 1–7) proposed an estimation procedure that makes no distributional assumption on the random effects but assumes independent within-subject measurement errors in the longitudinal covariate process. Based on an asymptotic bias analysis, we found that their estimators can be biased when random effects do not fully explain the within-subject correlations among longitudinal covariate measurements. Specifically, the existing procedure is fairly sensitive to the independent measurement error assumption. To overcome this limitation, we propose new estimation procedures that require neither a distributional or covariance structural assumption on covariate random-effects nor an independence assumption on within-subject measurement errors. These new procedures are more flexible, readily cover scenarios that have multivariate longitudinal covariate processes and can be calculated using available software. Through simulations and an analysis of data from a hypertension study, we evaluate and illustrate the numerical performances of the new estimators. PMID:17501940

  20. Random effects logistic models for analysing efficacy of a longitudinal randomized treatment with non-adherence.

    PubMed

    Small, Dylan S; Ten Have, Thomas R; Joffe, Marshall M; Cheng, Jing

    2006-06-30

    We present a random effects logistic approach for estimating the efficacy of treatment for compliers in a randomized trial with treatment non-adherence and longitudinal binary outcomes. We use our approach to analyse a primary care depression intervention trial. The use of a random effects model to estimate efficacy supplements intent-to-treat longitudinal analyses based on random effects logistic models that are commonly used in primary care depression research. Our estimation approach is an extension of Nagelkerke et al.'s instrumental variables approximation for cross-sectional binary outcomes. Our approach is easily implementable with standard random effects logistic regression software. We show through a simulation study that our approach provides reasonably accurate inferences for the setting of the depression trial under model assumptions. We also evaluate the sensitivity of our approach to model assumptions for the depression trial. Copyright (c) 2005 John Wiley & Sons, Ltd.

  1. Longitudinal trajectories of aberrant behavior in fragile X syndrome.

    PubMed

    Hustyi, Kristin M; Hall, Scott S; Jo, Booil; Lightbody, Amy A; Reiss, Allan L

    2014-11-01

    The Aberrant Behavior Checklist-Community (ABC-C; Aman et al., 1995) has been increasingly adopted as a primary tool for measuring behavioral change in clinical trials for individuals with fragile X syndrome (FXS). To our knowledge, however, no study has documented the longitudinal trajectory of aberrant behaviors in individuals with FXS using the ABC-C. As part of a larger longitudinal study, we examined scores obtained on the ABC-C subscales for 124 children and adolescents (64 males, 60 females) with FXS who had two or more assessments (average interval between assessments was approximately 4 years). Concomitant changes in age-equivalent scores on the Vineland Adaptive Behavior Scales (VABS) were also examined. As expected for an X-linked genetic disorder, males with FXS obtained significantly higher scores on all subscales of the ABC-C and significantly lower age-equivalent scores on the VABS than females with FXS. In both males and females with FXS, scores on the Irritability/Agitation and Hyperactivity/Noncompliance subscales of the ABC-C decreased significantly with age, with little to no change occurring over time on the Lethargy/Social Withdrawal, Stereotypic Behavior, and Inappropriate Speech subscales. The decrease in scores on the Hyperactivity/Noncompliance domain was significantly greater for males than for females. In both males and females, age-equivalent scores on the VABS increased significantly over this developmental period. These results establish a basis upon which to evaluate long-term outcomes from intervention-based research. However, longitudinal direct observational studies are needed to establish whether the severity of problem behavior actually decreases over time in this population. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Longitudinal modes along thin piezoelectric waveguides for liquid sensing applications.

    PubMed

    Caliendo, Cinzia

    2015-06-02

    The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN) is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0) and four higher order (S1, S2, S3, S4) symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment.

  3. Longitudinal Modes along Thin Piezoelectric Waveguides for Liquid Sensing Applications

    PubMed Central

    Caliendo, Cinzia

    2015-01-01

    The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN) is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0) and four higher order (S1, S2, S3, S4) symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment. PMID:26043174

  4. Longitudinal impedance of single frog muscle fibers

    PubMed Central

    1975-01-01

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

  5. Longitudinally extensive optic neuritis in pediatric patients.

    PubMed

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

    2015-01-01

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

  6. Ultimate Longitudinal Strength of Composite Ship Hulls

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  7. Transverse-longitudinal coupling in intense beams

    SciTech Connect

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

    1981-03-01

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

  8. The Lighthouse Program: A Longitudinal Research Project.

    ERIC Educational Resources Information Center

    LaRose, Barbara

    1986-01-01

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

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

    PubMed

    Farrington, D P

    1991-05-01

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

  10. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  11. Longitudinal space charge effects near transition

    SciTech Connect

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

    2009-05-04

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

  12. Longitudinal study of keratoconus progression.

    PubMed

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

    2007-10-01

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

  13. Longitudinal study of keratoconus progression

    PubMed Central

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

    2013-01-01

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

  14. Radial macrosegregation and dendrite clustering in directionally solidified Al-7Si and Al-19Cu alloys

    NASA Astrophysics Data System (ADS)

    Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2016-05-01

    Hypoeutectic Al-7 wt% Si and Al-19 wt% Cu alloys were directionally solidified upward in a Bridgman furnace through a range of constant growth speeds and thermal gradients. Though processing is thermo-solutally stable, flow initiated by gravity-independent advection at, slightly leading, central dendrites moves rejected solute out ahead and across the advancing interface. Here any lagging dendrites are further suppressed which promotes a curved solid-liquid interface and the eventual dendrite "clustering" seen in transverse sections (dendrite "steepling" in longitudinal orientations) as well as extensive radial macrosegregation. Both aluminum alloys showed considerable macrosegregation at the low growth speeds (10 and 30 μm s-1) but not at higher speed (72 μm s-1). Distribution of the fraction eutectic-constituent on transverse sections was determined in order to quantitatively describe radial macrosegregation. The convective mechanisms leading to dendrite-steepling were elucidated with numerical simulations, and their results compared with the experimental observations.

  15. Reconstruction of sub-femtosecond longitudinal bunch profile measurement data

    NASA Astrophysics Data System (ADS)

    Weikum, M. K.; Andonian, G.; Assmann, R. W.; Dorda, U.; Sheng, Z. M.

    2017-07-01

    With a current trend towards shorter electron beams with lengths on the order of few femtoseconds (fs) to sub-femtoseconds both in conventional and novel accelerator communities, the need for diagnostics with equivalent attosecond resolution is increasing. The proposed design for a sub-femtosecond diagnostic by Andonian et al. (2011, Phys. Rev. ST Accel. Beams 14 072802) is one such example that combines a laser deflector with an RF deflecting cavity to streak the electron beam in the horizontal and vertical direction. In this paper, we present a tool for the reconstruction of the longitudinal beam profile from this diagnostic data, which can be used both for the analysis of planned experiments and testing of different beam scenarios with respect to their specific setup requirements. Applying this method, the usefulness of the device for measurements in a number of example scenarios, including plasma-accelerated and ultrashort RF-accelerated electron beams, is discussed.

  16. A Longitudinal Study on Human Outdoor Decomposition in Central Texas.

    PubMed

    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.

  17. Growth and microstructure evolution of the Nb{sub 2}Al-Al{sub 3}Nb eutectic in situ composite

    SciTech Connect

    Rios, C.T.; Ferrandini, P.L.; Milenkovic, S.; Caram, R. . E-mail: rcaram@fem.unicamp.br

    2005-03-15

    In situ composite materials obtained by directional growth of eutectic alloys usually show improved properties, that make them potential candidates for high temperature applications. The eutectic alloy found in the Al-Nb system is composed of the two intermetallic phases Al{sub 3}Nb (D0{sub 22}) and Nb{sub 2}Al (D8{sub b}). This paper describes the directional solidification of an Al-Nb eutectic alloy using a Bridgman type facility at growth rates varying from 1.0 to 2.9 cm/h. Longitudinal and transverse sections of grown samples were characterized regarding the solidification microstructure by using optical and scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction. Despite both phases being intermetallic compounds, the eutectic microstructure obtained was very regular. The results obtained were discussed regarding the effect of the growth rate on the microstructure, lamellar-rod transition and variation of phase volume fraction.

  18. ALS2 mutations

    PubMed Central

    Schneider, Susanne A.; Carr, Lucinda; Deuschl, Guenther; Hopfner, Franziska; Stamelou, Maria; Wood, Nicholas W.; Bhatia, Kailash P.

    2014-01-01

    Objective: To determine the genetic etiology in 2 consanguineous families who presented a novel phenotype of autosomal recessive juvenile amyotrophic lateral sclerosis associated with generalized dystonia. Methods: A combination of homozygosity mapping and whole-exome sequencing in the first family and Sanger sequencing of candidate genes in the second family were used. Results: Both families were found to have homozygous loss-of-function mutations in the amyotrophic lateral sclerosis 2 (juvenile) (ALS2) gene. Conclusions: We report generalized dystonia and cerebellar signs in association with ALS2-related disease. We suggest that the ALS2 gene should be screened for mutations in patients who present with a similar phenotype. PMID:24562058

  19. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  20. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  1. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  2. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  3. 14 CFR 25.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  4. Eye-tracking in amyotrophic lateral sclerosis: A longitudinal study of saccadic and cognitive tasks

    PubMed Central

    Proudfoot, Malcolm; Menke, Ricarda A.L.; Sharma, Rakesh; Berna, Claire M.; Hicks, Stephen L.; Kennard, Christopher; Talbot, Kevin; Turner, Martin R.

    2016-01-01

    A relative preservation of eye movements is notable in ALS, but saccadic functions have not been studied longitudinally. ALS overlaps with FTD, typically involving executive dysfunction, and eye-tracking offers additional potential for the assessment of extramotor pathology where writing and speaking are both impaired. Eye-tracking measures (including anti-saccade, trail-making and visual search tasks) were assessed at six-monthly intervals for up to two years in a group of ALS (n = 61) and primary lateral sclerosis (n = 7) patients, compared to healthy age-matched controls (n = 39) assessed on a single occasion. Task performance was explored speculatively in relation to resting-state functional MRI (R-FMRI) network connectivity. Results showed that ALS patients were impaired on executive and visual search tasks despite normal basic saccadic function, and impairments in the PLS patients were unexpectedly often more severe. No significant progression was detected longitudinally in either group. No changes in R-FMRI network connectivity were identified in relation to patient performance. In conclusion, eye-tracking offers an objective means to assess extramotor cerebral involvement in ALS. The relative resistance of pure oculomotor function is confirmed, and higher-level executive impairments do not follow the same rate of decline as physical disability. PLS patients may have more cortical dysfunction than has been previously appreciated. PMID:26312652

  5. Eye-tracking in amyotrophic lateral sclerosis: A longitudinal study of saccadic and cognitive tasks.

    PubMed

    Proudfoot, Malcolm; Menke, Ricarda A L; Sharma, Rakesh; Berna, Claire M; Hicks, Stephen L; Kennard, Christopher; Talbot, Kevin; Turner, Martin R

    2015-01-01

    A relative preservation of eye movements is notable in ALS, but saccadic functions have not been studied longitudinally. ALS overlaps with FTD, typically involving executive dysfunction, and eye-tracking offers additional potential for the assessment of extramotor pathology where writing and speaking are both impaired. Eye-tracking measures (including anti-saccade, trail-making and visual search tasks) were assessed at six-monthly intervals for up to two years in a group of ALS (n = 61) and primary lateral sclerosis (n = 7) patients, compared to healthy age-matched controls (n = 39) assessed on a single occasion. Task performance was explored speculatively in relation to resting-state functional MRI (R-FMRI) network connectivity. Results showed that ALS patients were impaired on executive and visual search tasks despite normal basic saccadic function, and impairments in the PLS patients were unexpectedly often more severe. No significant progression was detected longitudinally in either group. No changes in R-FMRI network connectivity were identified in relation to patient performance. In conclusion, eye-tracking offers an objective means to assess extramotor cerebral involvement in ALS. The relative resistance of pure oculomotor function is confirmed, and higher-level executive impairments do not follow the same rate of decline as physical disability. PLS patients may have more cortical dysfunction than has been previously appreciated.

  6. The longitudinal development of social and executive functions in late adolescence and early adulthood.

    PubMed

    Taylor, Sophie J; Barker, Lynne A; Heavey, Lisa; McHale, Sue

    2015-01-01

    Our earlier work suggests that, executive functions and social cognition show protracted development into late adolescence and early adulthood (Taylor et al., 2013). However, it remains unknown whether these functions develop linearly or non-linearly corresponding to dynamic changes to white matter density at these age ranges. Executive functions are particularly in demand during the transition to independence and autonomy associated with this age range (Ahmed and Miller, 2011). Previous research examining executive function (Romine and Reynolds, 2005) and social cognition (Dumontheil et al., 2010a) in late adolescence has utilized a cross sectional design. The current study employed a longitudinal design with 58 participants aged 17, 18, and 19 years completing social cognition and executive function tasks, Wechsler Abbreviated Scale of Intelligence (Wechsler, 1999), Positive and Negative Affect Schedule (Watson et al., 1988), and Hospital Anxiety and Depression Scale (Zigmond and Snaith, 1983) at Time 1 with follow up testing 12-16 months later. Inhibition, rule detection, strategy generation and planning executive functions and emotion recognition with dynamic stimuli showed longitudinal development between time points. Self-report empathy and emotion recognition functions using visual static and auditory stimuli were stable by age 17 whereas concept formation declined between time points. The protracted development of some functions may reflect continued brain maturation into late adolescence and early adulthood including synaptic pruning (Sowell et al., 2001) and changes to functional connectivity (Stevens et al., 2007) and/or environmental change. Clinical implications, such as assessing the effectiveness of rehabilitation following Head Injury, are discussed.

  7. Initial Symptoms of ALS

    MedlinePlus

    ... Combine your passion and commitment to finding a cure for ALS while achieving physical challenges through athletic events Register ... - 1275 K Street NW - Suite 250 - Washington, DC 20005 All content and works posted on this website are owned ...

  8. Genetic Testing for ALS

    MedlinePlus

    ... Some medical centers may require a neurological exam, psychological assessment and counseling before predictive testing. If a person in the family with ALS has a negative genetic test result (no identified genetic mutation), testing family members ...

  9. Lou Gehrig's Disease (ALS)

    MedlinePlus

    ... when it becomes necessary. For instance, a power wheelchair can enable a paralyzed person with ALS to ... done these things despite being confined to a wheelchair for many years, being able to move only ...

  10. Rub al Khali, Arabia

    NASA Image and Video Library

    2008-08-08

    NASA Terra spacecraft shows the Rub al Khali, one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula; it includes parts of Oman, United Arab Emirates, and Yemen.

  11. Ag-Al-Ca

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Ag-Al-Ca' with the content:

  12. Frequently Asked Questions about ALS and the ALS Registry

    MedlinePlus

    ... long do people with familial ALS live? Do clusters of ALS possibly exist? (I have been told ... related?) What are the problems with studying possible clusters of ALS? What are motor neuron (nerve cell) ...

  13. Low Alpha Experiments at the ALS

    NASA Astrophysics Data System (ADS)

    Robin, D.; Alvis, R.; Jackson, A.; Holtzapple, R.; Podobedov, B.

    1996-04-01

    We present a modified, low alpha lattice for the Advanced Light Source where the quadrupole field strengths have been detuned to allow the momentum compaction factor to be varied smoothly from positive to negative values. With this low alpha lattice we decrease the momentum compaction factor by a factor of 5, to 0.0003 over normal operation, resulting in a measured bunch length reduction by a factor of 2. We also measure the size of the second-order momentum compaction factor as well as store beam in a negative momentum compaction lattice. Streak camera measurements at positive and negative momentum compaction operation show longitudinal beam profile distributions that are in agreement with simulations by Fang et al. (8).

  14. LONGITUDINAL SPACE CHARGE EFFECT FOR SNS

    SciTech Connect

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

    1998-06-22

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

  15. Longitudinal stability in multiharmonic standing wave linacs

    DOE PAGES

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

    2016-09-22

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

  16. Longitudinal stability in multiharmonic standing wave linacs

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  17. Longitudinal fluctuations and decorrelation of anisotropic flow

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  18. Multivariate analysis of longitudinal rates of change.

    PubMed

    Bryan, Matthew; Heagerty, Patrick J

    2016-12-10

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

  19. Epidemiology of ALS.

    PubMed

    Nelson, L M

    Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder of unknown etiology. ALS onset is rare before age 40 and increases with age thereafter. Men are at higher risk than women (ratio 1.3:1). Other than age and gender, the only indisputable risk factor for ALS is genetic susceptibility, with familial cases occurring in about 10% of most case series. Genetic linkage studies have provided evidence that a mutant form of the gene that codes for Cu/Zn superoxide dismutase, an endogenous free radical scavenger, is important in 15-20% of familial cases. Epidemiologic studies have identified associations of sporadic ALS with work in occupations that involve toxicant exposure. Environmental toxicants may act against a background of increased genetic susceptibility; however, genetically acquired biochemical defects have not been identified in sporadic ALS patients. Other epidemiologic theories of disease etiology have emphasized the potential role of physical trauma, electrical shock, and vigorous physical exertion, but evidence regarding these factors is inconsistent.

  20. Direct longitudinal laser acceleration of electrons in free space

    NASA Astrophysics Data System (ADS)

    Carbajo, Sergio; Nanni, Emilio A.; Wong, Liang Jie; Moriena, Gustavo; Keathley, Phillip D.; Laurent, Guillaume; Miller, R. J. Dwayne; Kärtner, Franz X.

    2016-02-01

    Compact laser-driven accelerators are pursued heavily worldwide because they make novel methods and tools invented at national laboratories widely accessible in science, health, security, and technology [V. Malka et al., Principles and applications of compact laser-plasma accelerators, Nat. Phys. 4, 447 (2008)]. Current leading laser-based accelerator technologies [S. P. D. Mangles et al., Monoenergetic beams of relativistic electrons from intense laser-plasma interactions, Nature (London) 431, 535 (2004); T. Toncian et al., Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons, Science 312, 410 (2006); S. Tokita et al. Single-shot ultrafast electron diffraction with a laser-accelerated sub-MeV electron pulse, Appl. Phys. Lett. 95, 111911 (2009)] rely on a medium to assist the light to particle energy transfer. The medium imposes material limitations or may introduce inhomogeneous fields [J. R. Dwyer et al., Femtosecond electron diffraction: "Making the molecular movie,", Phil. Trans. R. Soc. A 364, 741 (2006)]. The advent of few cycle ultraintense radially polarized lasers [S. Carbajo et al., Efficient generation of ultraintense few-cycle radially polarized laser pulses, Opt. Lett. 39, 2487 (2014)] has ushered in a novel accelerator concept [L. J. Wong and F. X. Kärtner, Direct acceleration of an electron in infinite vacuum by a pulsed radially polarized laser beam, Opt. Express 18, 25035 (2010); F. Pierre-Louis et al. Direct-field electron acceleration with ultrafast radially polarized laser beams: Scaling laws and optimization, J. Phys. B 43, 025401 (2010); Y. I. Salamin, Electron acceleration from rest in vacuum by an axicon Gaussian laser beam, Phys. Rev. A 73, 043402 (2006); C. Varin and M. Piché, Relativistic attosecond electron pulses from a free-space laser-acceleration scheme, Phys. Rev. E 74, 045602 (2006); A. Sell and F. X. Kärtner, Attosecond electron bunches accelerated and compressed by radially polarized laser

  1. Elasticity of single-crystal SmAlO 3, GdAlO 3 and ScAlO 3 perovskites

    NASA Astrophysics Data System (ADS)

    Bass, Jay D.

    1984-12-01

    The adiabatic single-crystal elastic moduli of SmAlO 3, GdAlO 3 and ScAlO 3, all with the orthorhombic perovskite structure, have been measured by Brillouin spectroscopy under ambient conditions. These 3 compounds display various degrees of crystallographic distortion from the ideal cubic perovskite structure. We find that longitudinal moduli in directions parallel to the axes of a pseudocubic subcell are nearly equal and insensitive to distortions of the crystal structure from cubic symmetry, whereas, the moduli C 11 and C 22, parallel to the orthorhombic axes, display pronounced anisotropy with the exception of ScAlO 3. The shear moduli also correlate with distortion from cubic symmetry, as measured by rotation, or tilt angles, of the AlO 6 octahedra. Our data support the observations of Liebermann et al. that perovskite-structure compounds define consistent elasticity trends relating bulk modulus and molar volume, and sound speed and mean atomic weight. These relationships have been used to estimate bulk and shear moduli for the high-pressure polymorphs of CaSiO 3 and MgSiO 3 with the perovskite structure.

  2. Statins: Do They Cause ALS?

    MedlinePlus

    Statins: Do they cause ALS? Do statins cause amyotrophic lateral sclerosis (ALS)? Answers from Francisco Lopez-Jimenez, M.D. ... D. References Sorensen HT, et al. Statins and amyotrophic lateral sclerosis: The level of evidence for an association. Journal ...

  3. Photoelectron spectroscopy of the aluminum hydride anions: AlH2-, AlH3-, Al2H6-, Al3H9-, and Al4H12-

    NASA Astrophysics Data System (ADS)

    Zhang, Xinxing; Wang, Haopeng; Collins, Evan; Lim, Alane; Ganteför, Gerd; Kiran, Boggavarapu; Schnöckel, Hansgeorg; Eichhorn, Bryan; Bowen, Kit

    2013-03-01

    We report measurements of the negative ion photoelectron spectra of the simple aluminum hydride anions: AlH2-, AlH3-, Al2H6-, Al3H9-, and Al4H12-. From these spectra, we measured the vertical detachment energies of the anions, and we estimated the electron affinities of their neutral counterparts. Our results for AlH2-, AlH3-, and Al2H6- were also compared with previous predictions by theory.

  4. Photoelectron spectroscopy of the aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-).

    PubMed

    Zhang, Xinxing; Wang, Haopeng; Collins, Evan; Lim, Alane; Ganteför, Gerd; Kiran, Boggavarapu; Schnöckel, Hansgeorg; Eichhorn, Bryan; Bowen, Kit

    2013-03-28

    We report measurements of the negative ion photoelectron spectra of the simple aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-). From these spectra, we measured the vertical detachment energies of the anions, and we estimated the electron affinities of their neutral counterparts. Our results for AlH2(-), AlH3(-), and Al2H6(-) were also compared with previous predictions by theory.

  5. Bunched beam longitudinal instability: Coherent dipole motion

    SciTech Connect

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

    1993-04-23

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

  6. Entanglement from longitudinal and scalar photons

    SciTech Connect

    Franson, J. D

    2011-09-15

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

  7. ALS superbend magnet system

    SciTech Connect

    Zbasnik, J.; Wang, S.T.; Chen, J.Y.; DeVries, G.J.; DeMarco, R.; Fahmie, M.; Geyer, A.; Green, M.A.; Harkins, J.; Henderson, T.; Hinkson, J.; Hoyer, E.H.; Krupnick, J.; Marks, S.; Ottens, F.; Paterson, J.A.; Pipersky, P.; Portmann, G.; Robin, D.A.; Schlueter, R.D.; Steier, C.; Taylor, C.E.; Wahrer, R.

    2000-09-15

    The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refrigeration. We also present the current status of fabrication and testing.

  8. Symmetric diffeomorphic modeling of longitudinal structural MRI.

    PubMed

    Ashburner, John; Ridgway, Gerard R

    2012-01-01

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

  9. Symmetric Diffeomorphic Modeling of Longitudinal Structural MRI

    PubMed Central

    Ashburner, John; Ridgway, Gerard R.

    2013-01-01

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

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

    PubMed Central

    Schaie, K. Warner

    2005-01-01

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

  11. Combined longitudinal and lateral control for automated vehicle guidance

    NASA Astrophysics Data System (ADS)

    Attia, Rachid; Orjuela, Rodolfo; Basset, Michel

    2014-02-01

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

  12. Al Shanker Remembers.

    ERIC Educational Resources Information Center

    American Educator, 2000

    2000-01-01

    In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

  13. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Integrated Risk Information System ( IRIS ) Chemical Assessment Summary U.S . Environmental Protection Agency National Center for Environmental Assessment This IRIS Summary has been removed from the IRIS database and is available for historical reference purposes . ( July 2016 ) Fosetyl - al ; CASRN

  14. LIFESPAN: A tool for the computer-aided design of longitudinal studies

    PubMed Central

    Brandmaier, Andreas M.; von Oertzen, Timo; Ghisletta, Paolo; Hertzog, Christopher; Lindenberger, Ulman

    2015-01-01

    Researchers planning a longitudinal study typically search, more or less informally, a multivariate space of possible study designs that include dimensions such as the hypothesized true variance in change, indicator reliability, the number and spacing of measurement occasions, total study time, and sample size. The main search goal is to select a research design that best addresses the guiding questions and hypotheses of the planned study while heeding applicable external conditions and constraints, including time, money, feasibility, and ethical considerations. Because longitudinal study selection ultimately requires optimization under constraints, it is amenable to the general operating principles of optimization in computer-aided design. Based on power equivalence theory (MacCallum et al., 2010; von Oertzen, 2010), we propose a computational framework to promote more systematic searches within the study design space. Starting with an initial design, the proposed framework generates a set of alternative models with equal statistical power to detect hypothesized effects, and delineates trade-off relations among relevant parameters, such as total study time and the number of measurement occasions. We present LIFESPAN (Longitudinal Interactive Front End Study Planner), which implements this framework. LIFESPAN boosts the efficiency, breadth, and precision of the search for optimal longitudinal designs. Its initial version, which is freely available at http://www.brandmaier.de/lifespan, is geared toward the power to detect variance in change as specified in a linear latent growth curve model. PMID:25852596

  15. LIFESPAN: A tool for the computer-aided design of longitudinal studies.

    PubMed

    Brandmaier, Andreas M; von Oertzen, Timo; Ghisletta, Paolo; Hertzog, Christopher; Lindenberger, Ulman

    2015-01-01

    Researchers planning a longitudinal study typically search, more or less informally, a multivariate space of possible study designs that include dimensions such as the hypothesized true variance in change, indicator reliability, the number and spacing of measurement occasions, total study time, and sample size. The main search goal is to select a research design that best addresses the guiding questions and hypotheses of the planned study while heeding applicable external conditions and constraints, including time, money, feasibility, and ethical considerations. Because longitudinal study selection ultimately requires optimization under constraints, it is amenable to the general operating principles of optimization in computer-aided design. Based on power equivalence theory (MacCallum et al., 2010; von Oertzen, 2010), we propose a computational framework to promote more systematic searches within the study design space. Starting with an initial design, the proposed framework generates a set of alternative models with equal statistical power to detect hypothesized effects, and delineates trade-off relations among relevant parameters, such as total study time and the number of measurement occasions. We present LIFESPAN (Longitudinal Interactive Front End Study Planner), which implements this framework. LIFESPAN boosts the efficiency, breadth, and precision of the search for optimal longitudinal designs. Its initial version, which is freely available at http://www.brandmaier.de/lifespan, is geared toward the power to detect variance in change as specified in a linear latent growth curve model.

  16. Proton irradiation studies on Al and Al5083 alloy

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, P.; Gayathri, N.; Bhattacharya, M.; Gupta, A. Dutta; Sarkar, Apu; Dhar, S.; Mitra, M. K.; Mukherjee, P.

    2017-10-01

    The change in the microstructural parameters and microhardness values in 6.5 MeV proton irradiated pure Al and Al5083 alloy samples have been evaluated using different model based techniques of X-ray diffraction Line Profile Analysis (XRD) and microindendation techniques. The detailed line profile analysis of the XRD data showed that the domain size increases and saturates with irradiation dose both in the case of Al and Al5083 alloy. The corresponding microstrain values did not show any change with irradiation dose in the case of the pure Al but showed an increase at higher irradiation doses in the case of Al5083 alloy. The microindendation results showed that unirradiated Al5083 alloy has higher hardness value compared to that of unirradiated pure Al. The hardness increased marginally with irradiation dose in the case of Al5083, whereas for pure Al, there was no significant change with dose.

  17. Longitudinal magnetization loss in twisted multifilamentary Bi2223 tape

    NASA Astrophysics Data System (ADS)

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

    2002-08-01

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

  18. Al Sumelat Water Network. Village of Al Sumelat, Iraq

    DTIC Science & Technology

    2006-03-15

    OFFICE OF THE SPECIAL INSPECTOR GENERAL FOR IRAQ RECONSTRUCTION AL SUMELAT WATER NETWORK VILLAGE OF AL SUMELAT, IRAQ...Sumelat Water Network Village of Al Sumelat, Iraq 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Al Sumelat Water Network Village of Al Sumelat, Iraq Synopsis Introduction. This report was previously provided on a limited distribution basis

  19. Analysis of baseline, average, and longitudinally measured blood pressure data using linear mixed models.

    PubMed

    Hossain, Ahmed; Beyene, Joseph

    2014-01-01

    This article compares baseline, average, and longitudinal data analysis methods for identifying genetic variants in genome-wide association study using the Genetic Analysis Workshop 18 data. We apply methods that include (a) linear mixed models with baseline measures, (b) random intercept linear mixed models with mean measures outcome, and (c) random intercept linear mixed models with longitudinal measurements. In the linear mixed models, covariates are included as fixed effects, whereas relatedness among individuals is incorporated as the variance-covariance structure of the random effect for the individuals. The overall strategy of applying linear mixed models decorrelate the data is based on Aulchenko et al.'s GRAMMAR. By analyzing systolic and diastolic blood pressure, which are used separately as outcomes, we compare the 3 methods in identifying a known genetic variant that is associated with blood pressure from chromosome 3 and simulated phenotype data. We also analyze the real phenotype data to illustrate the methods. We conclude that the linear mixed model with longitudinal measurements of diastolic blood pressure is the most accurate at identifying the known single-nucleotide polymorphism among the methods, but linear mixed models with baseline measures perform best with systolic blood pressure as the outcome.

  20. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

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

  1. Collaborative Knowledge-Building: A Longitudinal Study

    ERIC Educational Resources Information Center

    Li, Qing

    2009-01-01

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

  2. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

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

  3. Delinquency Prone Youth: Longitudinal and Preventive Research.

    ERIC Educational Resources Information Center

    Benning, James J.; And Others

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

  4. Managing Organizational Commitment: Insights from Longitudinal Research

    ERIC Educational Resources Information Center

    Morrow, Paula C.

    2011-01-01

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

  5. Teaching Technology Longitudinally to Virtual Children

    ERIC Educational Resources Information Center

    Matthews, Lynley

    2010-01-01

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

  6. Conducting Three-Level Longitudinal Analyses

    ERIC Educational Resources Information Center

    Peugh, James L.; Heck, Ronald H.

    2017-01-01

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

  7. Longitudinal Predictors of High School Completion

    ERIC Educational Resources Information Center

    Barry, Melissa; Reschly, Amy L.

    2012-01-01

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

  8. The Tevatron bunch by bunch longitudinal dampers

    SciTech Connect

    Cheng-Yang Tan and James Steimel

    2002-09-25

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

  9. Religion and Aging in a Longitudinal Panel

    ERIC Educational Resources Information Center

    Blazer, Dan; Palmore, Erdman

    1976-01-01

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

  10. The Merits of Using Longitudinal Mediation

    ERIC Educational Resources Information Center

    Jose, Paul E.

    2016-01-01

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

  11. Issues in Longitudinal Research on Motivation

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  12. The Merits of Using Longitudinal Mediation

    ERIC Educational Resources Information Center

    Jose, Paul E.

    2016-01-01

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

  13. MPCP Longitudinal Educational Growth Study Baseline Report

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  14. Emotion Regulation and Childhood Aggression: Longitudinal Associations

    ERIC Educational Resources Information Center

    Roll, Judith; Koglin, Ute; Petermann, Franz

    2012-01-01

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

  15. Conducting Three-Level Longitudinal Analyses

    ERIC Educational Resources Information Center

    Peugh, James L.; Heck, Ronald H.

    2017-01-01

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

  16. Design and Implementation Issues in Longitudinal Research

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  17. Longitudinal Studies--Are They Worth It?

    ERIC Educational Resources Information Center

    Cowley, Judith

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

  18. An Early Intervention Project: A Longitudinal Look.

    ERIC Educational Resources Information Center

    Gordon, Ira J.

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

  19. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  20. 14 CFR 23.145 - Longitudinal control.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  1. Longitudinal Predictors of High School Completion

    ERIC Educational Resources Information Center

    Barry, Melissa; Reschly, Amy L.

    2012-01-01

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

  2. Longitudinal photosynthetic gradient in crust lichens' thalli.

    PubMed

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

    2014-05-01

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

  3. Emotion Regulation and Childhood Aggression: Longitudinal Associations

    ERIC Educational Resources Information Center

    Roll, Judith; Koglin, Ute; Petermann, Franz

    2012-01-01

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

  4. Investigating Ceiling Effects in Longitudinal Data Analysis

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  5. Preschool Fears: Longitudinal Sequence and Cohort Changes.

    ERIC Educational Resources Information Center

    Draper, Thomas W.; James, Rebecca Smoak

    1985-01-01

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

  6. The National Longitudinal Surveys Handbook. Revised.

    ERIC Educational Resources Information Center

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

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

  7. Are Sibling Relationships Protective? A Longitudinal Study

    ERIC Educational Resources Information Center

    Gass, Krista; Jenkins, Jennifer; Dunn, Judy

    2007-01-01

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

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

    ERIC Educational Resources Information Center

    Demchik, Michael J.

    1999-01-01

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

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

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

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

  10. ALS insertion devices

    NASA Astrophysics Data System (ADS)

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W. V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1991-08-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system.

  11. Operation and performance of a longitudinal damping system using parallel digital signal processing

    SciTech Connect

    Fox, J.D.; Hindi, H.; Linscott, I.

    1994-06-01

    A programmable longitudinal feedback system based on four AT&T 1610 digital signal processors has been developed as a component of the PEP-II R&D program. This Longitudinal Quick Prototype is a proof of concept for the PEP-II system and implements full speed bunch-by-bunch signal processing for storage rings with bunch spacings of 4 ns. The design implements, via software, a general purpose feedback controller which allows the system to be operated at several accelerator facilities. The system configuration used for tests at the LBL Advanced Light Source is described. Open and closed loop results showing the detection and calculation of feedback signals from bunch motion are presented, and the system is shown to damp coupled-bunch instabilities in the ALS. Use of the system for accelerator diagnostics is illustrated via measurement of injection transients and analysis of open loop bunch motion.

  12. Doubly robust estimation of generalized partial linear models for longitudinal data with dropouts.

    PubMed

    Lin, Huiming; Fu, Bo; Qin, Guoyou; Zhu, Zhongyi

    2017-04-03

    We develop a doubly robust estimation of generalized partial linear models for longitudinal data with dropouts. Our method extends the highly efficient aggregate unbiased estimating function approach proposed in Qu et al. (2010) to a doubly robust one in the sense that under missing at random (MAR), our estimator is consistent when either the linear conditional mean condition is satisfied or a model for the dropout process is correctly specified. We begin with a generalized linear model for the marginal mean, and then move forward to a generalized partial linear model, allowing for nonparametric covariate effect by using the regression spline smoothing approximation. We establish the asymptotic theory for the proposed method and use simulation studies to compare its finite sample performance with that of Qu's method, the complete-case generalized estimating equation (GEE) and the inverse-probability weighted GEE. The proposed method is finally illustrated using data from a longitudinal cohort study.

  13. Longitudinal Multitrait-Multimethod Models for Developmental Research

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  14. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  15. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  16. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  17. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  18. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  19. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  20. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  1. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  2. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  3. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  5. 49 CFR 238.405 - Longitudinal static compressive strength.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  6. 14 CFR 23.175 - Demonstration of static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  7. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  8. 14 CFR 29.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  9. 46 CFR 154.176 - Longitudinal contiguous hull structure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  10. New waveguide-type HOM damper for ALS storage ring cavities.

    SciTech Connect

    Kwiatkowski, Slawomir; Baptiste, Kenneth; Julian, James

    2004-06-28

    The ALS storage ring 500 MHz RF system uses two re-entrant accelerating cavities powered by a single 320kW PHILLIPS YK1305 klystron. During several years of initial operation, the RF cavities were not equipped with effective passive HOM damper systems. Longitudinal beam stability was achieved through cavity temperature control and the longitudinal feedback system (LFB), which was often operating at the edge of its capabilities. As a result, longitudinal beam stability was a significant operations issue at the ALS. During two consecutive shutdown periods (April 2002 and 2003) we installed E-type HOM dampers on the main and third harmonic cavities. These devices dramatically decreased the Q-values of the longitudinal anti-symmetric HOM modes. The next step is to damp the rest of the longitudinal HOM modes in the main cavities below the synchrotron radiation damping level. This will hopefully eliminate the need for the LFB and set the stage for a possible increase in beam current. The ''waveguide'' type of HOM damper was the only option that didn't significantly compromise the vacuum performance of the RF cavity. The design process and the results of the low level measurements of the new waveguide dampers are presented in this paper.

  11. Longitudinal change in working memory as a function of APOE genotype in midlife and old age.

    PubMed

    Greenwood, Pamela M; Espeseth, Thomas; Lin, Ming-Kuan; Reinvang, Ivar; Parasuraman, Raja

    2014-06-01

    Previous investigations into whether the APOE-ε4 allele exerts cognitive effects at midlife have been inconclusive. We have advanced a "cognitive phenotype" hypothesis arguing that the ε4 allele of the apolipoprotein E gene (APOE) is associated with lower efficiency of neuronal plasticity thereby resulting in poorer cognitive performance independently of the pathology of Alzheimer's disease (Greenwood et al., ). This hypothesis is best tested at midlife, prior to the neuron loss associated with AD diagnosis. This hypothesis predicts that the ε4 allele would alter cognition regardless of age through plasticity mechanisms, but would not induce longitudinal decline in midlife. The alternative "prodrome" hypothesis predicts that the APOE-ε4 allele would be associated with longitudinal cognitive decline as early as midlife due to prodromal effects of AD. We tested these hypotheses with a working memory task in a large cross-sectional sample of cognitively screened APOE-ε4 carriers and non-carriers and also in a small longitudinal sample over 3 years. The sample was divided into middle-aged (mean age 50, range 40-59) and older (mean age 69, range 60-84) individuals. Cross-sectionally, we observed that older, but not middle-aged, APOE-ε4 carriers had lower accuracy than ε4 non-carriers, mainly under the hardest discrimination condition. Longitudinally, we observed increases in accuracy in middle-aged APOE-ε4 carriers, suggesting a cognitive phenotype that includes ability to benefit from experience. We observed a longitudinal decrease in older APOE-ε4 carriers, suggesting an AD prodrome. © 2014 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    2011-07-01

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

  13. Longitudinal Trajectories of Cigarette Smoking Following Rape

    PubMed Central

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

    2009-01-01

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

  14. Longitudinal variations of the equatorial electojet

    NASA Astrophysics Data System (ADS)

    Shume, Esayas

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

  15. Linac Coherent Light Source Longitudinal Feedback Model

    SciTech Connect

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

    2005-06-15

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

  16. Left ventricular longitudinal strain in soccer referees.

    PubMed

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

    2017-02-09

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

  17. A longitudinal analysis of teenage drinking patterns.

    PubMed

    Shahtahmasebi, Said; Berridge, Damon

    2009-01-01

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

  18. Left ventricular longitudinal strain in soccer referees

    PubMed Central

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

    2017-01-01

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

  19. Multivariate Longitudinal Analysis with Bivariate Correlation Test.

    PubMed

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

    2016-01-01

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

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

    PubMed

    Sabuncu, Mert R

    2015-10-01

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

  1. Longitudinal oscillation of intensity fronts in a strand at the edge of an active region

    SciTech Connect

    Guo, L.-J.; Tu, C.-Y.; He, J.-S.; Marsch, E.

    2010-03-25

    The edge of a solar active region (AR) is considered as a possible source region of the slow solar wind. Winebarger et al.(2001) observed outflows from an AR with velocities between 5 and 20 km/s. Recently, Sakao et al.(2007) reported the outflow of X-ray-emitting plasma from the edge of an AR. This outflow was inferred from the observation of outward traveling intensity enhancements. However, in Robbrecht et al.(2001), propagation of slow magnetoacoustic waves along the strand was considered as the possible cause for the longitudinal extension of the strand. Whether this phenomenon relates to a slow-mode wave or the outflow of plasma or a heating process of different parts of the strand is still an open question. Here we try to identify the nature of such a traveling event through studying the longitudinal motions of certain intensity level fronts in the strand. We find that the intensity front is oscillating like a sinusoidal signal along the strand with a period of 11 minutes. This result suggests that the oscillation might be partly related with the 5-minute p-mode oscillation in the photosphere. Moreover, we find that such oscillation of intensity-level fronts can be described by a model in which the strand has periodic extension. Yet, the relation between the extending strand and slow solar wind needs to be further studied.

  2. Nonlinear longitudinal control of a supermaneuverable aircraft

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  3. Nonlinear longitudinal control of a supermaneuverable aircraft

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  4. Marginal longitudinal semiparametric regression via penalized splines

    PubMed Central

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

    2010-01-01

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

  5. Moving Block Bootstrap for Analyzing Longitudinal Data

    PubMed Central

    Ju, Hyunsu

    2015-01-01

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

  6. Anterior longitudinal aortotomy in aortic valve replacement.

    PubMed

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

    2016-02-01

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

  7. RADON reconstruction in longitudinal phase space

    SciTech Connect

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

    1997-07-01

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

  8. CLADA: cortical longitudinal atrophy detection algorithm.

    PubMed

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2011-01-01

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

  9. CLADA: Cortical Longitudinal Atrophy Detection Algorithm

    PubMed Central

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2010-01-01

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

  10. Moving Block Bootstrap for Analyzing Longitudinal Data.

    PubMed

    Ju, Hyunsu

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

  11. Longitudinal analysis of mouse SDOCT volumes

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  12. Partly conditional survival models for longitudinal data.

    PubMed

    Zheng, Yingye; Heagerty, Patrick J

    2005-06-01

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

  13. Longitudinal Electroproduction of Charged Pions from

    SciTech Connect

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

    2001-11-12

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

  14. Longitudinal wakefield for an axisymmetric collimator

    SciTech Connect

    Blednykh A.; Krinsky, S.

    2012-05-25

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

  15. Longitudinal analysis of attitudes toward wolves.

    PubMed

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

    2013-04-01

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

  16. Material deprivation and health: a longitudinal study.

    PubMed

    Tøge, Anne Grete; Bell, Ruth

    2016-08-08

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

  17. Quality of reporting of observational longitudinal research.

    PubMed

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

    2005-02-01

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

  18. Magnetization Transfer Induced Biexponential Longitudinal Relaxation

    PubMed Central

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

    2009-01-01

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

  19. Nucleon Spin Structure: Longitudinal and Transverse

    SciTech Connect

    Jian-Ping Chen

    2011-02-01

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

  20. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  1. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

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

    PubMed

    Hu, Bo; Li, Liang; Greene, Tom

    2016-07-30

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

  3. AL Amyloidosis and Agent Orange

    MedlinePlus

    ... for survivors' benefits . Research on AL amyloidosis and herbicides The Health and Medicine Division (formally known as ... to the compounds of interest found in the herbicide Agent Orange and AL amyloidosis." VA made a ...

  4. The longitudinal development of social and executive functions in late adolescence and early adulthood

    PubMed Central

    Taylor, Sophie J.; Barker, Lynne A.; Heavey, Lisa; McHale, Sue

    2015-01-01

    Our earlier work suggests that, executive functions and social cognition show protracted development into late adolescence and early adulthood (Taylor et al., 2013). However, it remains unknown whether these functions develop linearly or non-linearly corresponding to dynamic changes to white matter density at these age ranges. Executive functions are particularly in demand during the transition to independence and autonomy associated with this age range (Ahmed and Miller, 2011). Previous research examining executive function (Romine and Reynolds, 2005) and social cognition (Dumontheil et al., 2010a) in late adolescence has utilized a cross sectional design. The current study employed a longitudinal design with 58 participants aged 17, 18, and 19 years completing social cognition and executive function tasks, Wechsler Abbreviated Scale of Intelligence (Wechsler, 1999), Positive and Negative Affect Schedule (Watson et al., 1988), and Hospital Anxiety and Depression Scale (Zigmond and Snaith, 1983) at Time 1 with follow up testing 12–16 months later. Inhibition, rule detection, strategy generation and planning executive functions and emotion recognition with dynamic stimuli showed longitudinal development between time points. Self-report empathy and emotion recognition functions using visual static and auditory stimuli were stable by age 17 whereas concept formation declined between time points. The protracted development of some functions may reflect continued brain maturation into late adolescence and early adulthood including synaptic pruning (Sowell et al., 2001) and changes to functional connectivity (Stevens et al., 2007) and/or environmental change. Clinical implications, such as assessing the effectiveness of rehabilitation following Head Injury, are discussed. PMID:26441579

  5. Al Qaeda as a System

    DTIC Science & Technology

    2006-03-15

    either as welcome guests or parasites . As welcome guests, Al Qaeda members take sanctuary in sponsor states. Sponsor states provide Al Qaeda with...sponsorship, Al Qaeda takes sanctuary as parasites either overtly or covertly. They take overt sanctuary in countries that publicly claim a policy...39 Yehudit Barsky, “Al Qa’ida, Iran, and Hezbollah: A Continuing Symbiosis ,” The American Jewish Committee Series on Terrorism , February 2004, 2-3

  6. Residual stresses in continuous graphite fiber Al metal matrix composites

    NASA Technical Reports Server (NTRS)

    Park, Hun Sub; Zong, Gui Sheng; Marcus, Harris L.

    1988-01-01

    The residual stresses in graphite fiber reinforced aluminum (Gr/Al) composites with various thermal histories are measured using X-ray diffraction (XRD) methods. The XRD stress analysis is based on the determination of lattice strains by precise measurements of the interplanar spacings in different directions of the sample. The sample is a plate consisting of two-ply P 100 Gr/Al 6061 precursor wires and Al 6061 overlayers. Prior to XRD measurement, the 6061 overlayers are electrochemically removed. In order to calibrate the relationship between stress magnitude and lattice spacing shift, samples of Al 6061 are loaded at varying stress levels in a three-point bend fixture, while the stresses are simultaneously determined by XRD and surface-attached strain gages. The stresses determined by XRD closely match those determined by the strain gages. Using these calibrations, the longitudinal residual stresses of P 100 Gr/Al 6061 composites are measured for various heat treatments, and the results are presented.

  7. Residual stresses in continuous graphite fiber Al metal matrix composites

    NASA Technical Reports Server (NTRS)

    Park, Hun Sub; Zong, Gui Sheng; Marcus, Harris L.

    1988-01-01

    The residual stresses in graphite fiber reinforced aluminum (Gr/Al) composites with various thermal histories are measured using X-ray diffraction (XRD) methods. The XRD stress analysis is based on the determination of lattice strains by precise measurements of the interplanar spacings in different directions of the sample. The sample is a plate consisting of two-ply P 100 Gr/Al 6061 precursor wires and Al 6061 overlayers. Prior to XRD measurement, the 6061 overlayers are electrochemically removed. In order to calibrate the relationship between stress magnitude and lattice spacing shift, samples of Al 6061 are loaded at varying stress levels in a three-point bend fixture, while the stresses are simultaneously determined by XRD and surface-attached strain gages. The stresses determined by XRD closely match those determined by the strain gages. Using these calibrations, the longitudinal residual stresses of P 100 Gr/Al 6061 composites are measured for various heat treatments, and the results are presented.

  8. Fasciculation potentials and earliest changes in motor unit physiology in ALS.

    PubMed

    de Carvalho, Mamede; Swash, Michael

    2013-09-01

    There is little information on the earliest changes in motor unit (MU) physiology in amyotrophic lateral sclerosis (ALS) and the development of the classical neurophysiological features of ALS over time. We studied the earliest abnormalities in MU physiology in ALS and changes over time. Observational, cross-sectional and longitudinal study. We studied the tibialis anterior (TA) muscle in three groups of subjects; 73 patients with ALS, 10 with benign fasciculation and 37 healthy control subjects. In the ALS group, 61 had normal strength in the TA muscle and 12 had TA muscle strength of 4 on the medical research council scale. In all subjects we evaluated the presence of fasciculation potentials (FPs) and fibrillation/sharp-waves (fibs-sw), and quantified MU potentials (MUPs) and jitter. Twenty-six ALS patients with TA muscle of normal strength were investigated in serial studies. FPs were recorded in TA muscles (medical research council 5) of 21 ALS patients with normal MUPs. Longitudinal studies confirmed that the patients presenting with FPs as the only abnormality progressed to MUP instability before large MUPs associated with fibs-sw were detected. FPs from ALS patients with no other neurophysiological change were simpler than in patients in whom there were also fibs-sw and neurogenic MUPs. The complexity of FPs in patients with weak TA muscle was greater than in the latter group. FPs in patients with benign fasciculations were simpler than FPs in ALS patients with normal TA muscle strength. FPs are a very early marker of ALS and anticipate MUP instability or reinnervation, consistent with a very early phase of increased axonal excitability. Later, widespread neuronal dysfunction causes widespread fibs-sw and loss of MUPs with compensatory reinnervation. Our results confirm the importance of FP morphology analysis in the differential diagnosis of ALS and other disorders, and indicate that benign FPs represent a different phenomenon.

  9. Operation and performance of a longitudinal feedback system using digital signal processing

    SciTech Connect

    Teytelman, D.; Fox, J.; Hindi, H.

    1994-11-22

    A programmable longitudinal feedback system using a parallel array of AT&T 1610 digital signal processors has been developed as a component of the PEP-II R&D program. This system has been installed at the Advanced Light Source (LBL) and implements full speed bunch by bunch signal processing for storage rings with bunch spacing of 4ns. Open and closed loop results showing the action of the feedback system are presented, and the system is shown to damp coupled-bunch instabilities in the ALS. A unified PC-based software environment for the feedback system operation is also described.

  10. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  11. Local surface skimming longitudinal wave velocity and residual stress mapping.

    PubMed

    Sathish, Shamachary; Martin, Richard W; Moran, Thomas J

    2004-01-01

    Local variation in surface skimming longitudinal wave (SSLW) velocity has been measured using a scanning acoustic microscope. A very narrow width electrical impulse has been used to excite the transducer of the acoustic lens. This permits the separation of the SSLW signal from the direct reflected signal in the time domain. A simple method of measuring the time delay between the directly reflected signal and the SSLW signal at two defocuses has been utilized for the local measurement of SSLW velocity. The variation in the SSLW velocity measured over an area of the sample is scaled and presented as an image. The method has been implemented to image the variation of the SSLW velocity around a crack tip in a sample of Ti-6Al-4V. Since the SSLW velocity is known to change linearly with the stress, the SSLW velocity image is considered as a representation of the image of stress around the crack tip. Local stress variation in the same region of the crack tip is directly measured using x-ray diffraction. The SSLW velocity image is compared with the x-ray diffraction stress image. The contrast in the two images, spatial resolution, and the penetration depth into the sample of acoustic waves and x rays are discussed.

  12. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    NASA Astrophysics Data System (ADS)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  13. Submicron Nb-Al/Al oxide-Nb tunnel junctions sandwiched between Al films

    NASA Astrophysics Data System (ADS)

    Maier, D.; Rothermel, H.; Gundlach, K. H.; Zimmermann, R.

    1996-02-01

    A process has been developed to embed Nb-Al/Al oxide-Nb junctions in planar structures of Al films. The submicron junctions are defined by photoresist lines. Motivation for this effort is a possible application of Nb junctions confined between normal conducting Al films as mixers above 700 GHz where Nb films loose their superconductive properties and tuning circuits made out of Nb therefore exhibit losses. First mixer results at 816 GHz are presented.

  14. Novel and emerging strategies for longitudinal data collection.

    PubMed

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

    2015-03-01

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

  15. Growth and Optical Properties of Al rich AlN/AlGaN Quantum Wells

    NASA Astrophysics Data System (ADS)

    Tahtamouni, T. M. Al; Nepal, N.; Nakarmi, M. L.; Lin, J. Y.; Jiang, H. X.

    2006-03-01

    Al rich AlGaN alloys are promising materials for the applications in the optoelectronic devices such as deep ultraviolet (UV) emitters and detectors in the spectral range down to 200 nm. AlGaN based UV emitters (λ<340nm) has applications in bio-chemical agent detection and medical research/ health care. To realize deep UV emission (λ< 280 nm) Al rich AlGaN based quantum wells (QWs) are required. We report here the growth of AlN/AlxGa1-xNQWs (x>0.65) on AlN/sapphire templates by metalorganic chemical vapor deposition (MOCVD). Deep UV photoluminescence (PL) was employed to study the optical properties of the QWs. Well width (Al composition) dependence was studied by varying the QW thickness (Al composition) with fixed x ˜ 0.65 (well width at 3 nm). Optical properties of these QWs such as the effects of alloy fluctuation, temperature, strain and piezoelectric field, carrier and exciton localizations on the quantum efficiency have been studied. Carrier and exciton dynamics were probed. Implications of our findings on the applications of Al rich AlN/AlGaN QWs for UV emitters and detectors will also be discussed.

  16. Viscous and acoustic properties of AlCu melts

    NASA Astrophysics Data System (ADS)

    Khusnutdinoff, R. M.; Mokshin, A. V.; Menshikova, S. G.; Beltyukov, A. L.; Ladyanov, V. I.

    2016-05-01

    The atomic dynamics of the binary Al100- x Cu x system is simulated at a temperature T = 973 K, a pressure p = 1.0 bar, and various copper concentrations x. These conditions (temperature, pressure) make it possible to cover the equilibrium liquid Al100- x Cu x phase at copper concentrations 0 ≤ x ≤ 40% and the supercooled melt in the concentration range 40% ≤ x ≤ 100%. The calculated spectral densities of the time correlation functions of the longitudinal {tilde C_L}( k, ω) and transverse {tilde C_T}( k, ω) currents in the Al100- x Cu x melt at a temperature T = 973 K reveal propagating collective excitations of longitudinal and transverse polarizations in a wide wavenumber range. It is shown that the maximum sound velocity in the v L ( x) concentration dependence takes place for the equilibrium melt at an atomic copper concentration x = 10 ± 5%, whereas the supercooled Al100- x Cu x melt saturated with copper atoms ( x ≥ 40%) is characterized by the minimum sound velocity. In the case of the supercooled melt, the concentration dependence of the kinematic viscosity ν( x) is found to be interpolated by a linear dependence, and a deviation from the linear dependence is observed in the case of equilibrium melt at x < 40%. An insignificant shoulder in the ν( x) dependence is observed at low copper concentrations ( x < 20%), and it is supported by the experimental data. This shoulder is caused by the specific features in the concentration dependence of the density ρ( x).

  17. Studies of 27Al NMR in SrAl4

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Higa, Nonoka; Kuroshima, Hiroko; Toji, Tatsuki; Morishima, Mach; Minei, Motofumi; Yogi, Mamoru; Nakamura, Ai; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika; Harima, Hisatomo

    A charge density wave (CDW) transition at TCDW = 243 K and a structural phase (SP) transition at approximately 100 K occur in SrAl4 with the BaAl4-type body center tetragonal structure, which is the divalent and non-4f electron reference compound of EuAl4. To understand the behaviors of the CDW and SP transitions, the 27Al NMR measurements using a single crystal and a powder sample of SrAl4 have been carried out. The line width below TCDW is modulated by an electrical quadruple interaction between 27Al nucleus and CDW charge modulation. The incommensurate CDW state below TCDW changes into a different structure below TSP. The temperature dependences of Knight shifts of 27Al(I) and 27Al(II) show the different behaviors. The temperature variation of 27Al(I) Knight shift shows anomalies at the CDW and SP transition temperatures, revealing the shift to negative side below TCDW, which is attributable to the core polarization of the d-electrons. However, 27Al(II) Knight shift keeps almost constant except for the small shift due to the SP transition. The 1/T1T of 27Al(I) indicates the obvious changes due to the CDW and SP transitions, while that of 27Al(II) takes a constant value. The density of state at the Fermi level at Al(I) site below 60 K would be about 0.9 times less than that above TCDW.

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

    PubMed

    Häfner, H; an der Heiden, W

    2000-05-01

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

  19. Spontaneous Cervical Intradural Disc Herniation Associated with Ossification of Posterior Longitudinal Ligament

    PubMed Central

    Wang, Dachuan; Wang, Haifeng; Shen, Wun-Jer

    2014-01-01

    Intradural herniation of a cervical disc is rare; less than 35 cases have been reported to date. A 52-year-old man with preexisting ossification of posterior longitudinal ligament developed severe neck pain with Lt hemiparesis while asleep. Neurological exam was consistent with Brown-Séquard syndrome. Magnetic resonance images showed a C5-6 herniated disc that was adjacent to the ossified ligament and indenting the cord. The mass was surrounded by cerebrospinal fluid signal intensity margin, and caudally the ventral dura line appears divided into two, consistent with the “Y-sign” described by Sasaji et al. Cord edema were noted. Because of preexisting canal stenosis and spinal cord at risk, a laminoplasty was performed, followed by an anterior C6 corpectomy. Spot-weld type adhesions of the posterior longitudinal ligament to the dura was noted, along with a longitudinal tear in the dura. An intradural extra-arachnoid fragment of herniated disc was removed. Clinical exam at 6 months after surgery revealed normal muscle strength but persistent mild paresthesias. It is difficult to make a definite diagnosis of intradural herniation preoperatively; however, the clinical findings and radiographic signs mentioned above are suggestive and should alert the surgeon to look for an intradural fragment. PMID:25295205

  20. Emotion regulation and childhood aggression: longitudinal associations.

    PubMed

    Röll, Judith; Koglin, Ute; Petermann, Franz

    2012-12-01

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

  1. Fracture structure near a longitudinal shear macrorupture

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  2. Linear stability of streamwise developing longitudinal vortices

    NASA Technical Reports Server (NTRS)

    Spall, Robert E.

    1993-01-01

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

  3. Longitudinal Diagnostics for Short Electron Beam Bunches

    SciTech Connect

    Loos, H.; /SLAC

    2010-06-11

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

  4. Piezoelectric Response to Coherent Longitudinal and Transverse Acoustic Phonons in a Semiconductor Schottky Diode

    NASA Astrophysics Data System (ADS)

    Srikanthreddy, D.; Glavin, B. A.; Poyser, C. L.; Henini, M.; Lehmann, D.; Jasiukiewicz, Cz.; Akimov, A. V.; Kent, A. J.

    2017-02-01

    We study the generation of microwave electronic signals by pumping a (311) GaAs Schottky diode with compressive and shear acoustic phonons, generated by the femtosecond optical excitation of an Al film transducer and mode conversion at the Al-GaAs interface. They propagate through the substrate and arrive at the Schottky device on the opposite surface, where they induce a microwave electronic signal. The arrival time, the amplitude, and the polarity of the signals depend on the phonon mode. A theoretical analysis is made of the polarity of the experimental signals. This analysis includes the piezoelectric and deformation potential mechanisms of electron-phonon interaction in a Schottky contact and shows that the piezoelectric mechanism is dominant for both transverse and longitudinal modes with frequencies below 250 and 70 GHz, respectively.

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

    ERIC Educational Resources Information Center

    Adelstein, Diane M.; Webster, Dennis W.

    1979-01-01

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

  6. A Class of Markov Models for Longitudinal Ordinal Data

    PubMed Central

    Lee, Keunbaik; Daniels, Michael J.

    2009-01-01

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

  7. Longitudinal Studies of Attitude Change: Issues and Methods

    DTIC Science & Technology

    1975-04-01

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

  8. Morton et al. Reply

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  9. Morton et al. Reply

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  10. Rub' al Khali, Arabia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.

    The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. Splinting of Longitudinal Fracture: An Innovative Approach

    PubMed Central

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

    2016-01-01

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

  12. Analyzing incomplete longitudinal clinical trial data.

    PubMed

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

    2004-07-01

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

  13. Analysis strategies for longitudinal attachment loss data.

    PubMed

    Beck, J D; Elter, J R

    2000-02-01

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

  14. Longitudinal Predictors of Institutionalization in Old Age

    PubMed Central

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

    2015-01-01

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

  15. Preceptor teaching tips in longitudinal clerkships.

    PubMed

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

    2016-06-01

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

  16. Anonymization of Longitudinal Electronic Medical Records

    PubMed Central

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

    2013-01-01

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

  17. A longitudinal study of urea cycle disorders.

    PubMed

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

    2014-01-01

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

  18. Optimization of longitudinal corrections of helical gears

    NASA Astrophysics Data System (ADS)

    He, Dawei; Fang, Zongde

    1992-07-01

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

  19. MULTILINEAR TENSOR REGRESSION FOR LONGITUDINAL RELATIONAL DATA.

    PubMed

    Hoff, Peter D

    2015-09-01

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

  20. Colorado longitudinal twin study of reading disability.

    PubMed

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

    2007-12-01

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

  1. Splinting of Longitudinal Fracture: An Innovative Approach.

    PubMed

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

    2016-01-01

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

  2. Parental mediation and cyberbullying - a longitudinal study.

    PubMed

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

    2014-01-01

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

  3. Initial Cognitive Performance Predicts Longitudinal Aviator Performance

    PubMed Central

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

    2011-01-01

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

  4. Longitudinal Predictors of Institutionalization in Old Age.

    PubMed

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

    2015-01-01

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

  5. A longitudinal study of urea cycle disorders

    PubMed Central

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

    2014-01-01

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

  6. Multivariate Longitudinal Analysis with Bivariate Correlation Test

    PubMed Central

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

    2016-01-01

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

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

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

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

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

    PubMed

    Harkness, Patrick; Lucas, Margaret; Cardoni, Andrea

    2012-12-01

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

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

    PubMed Central

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

    2007-01-01

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

  10. On the east-west longitudinally asymmetric distribution of solar proton events

    NASA Astrophysics Data System (ADS)

    He, H.-Q.; Wan, W.

    2017-01-01

    A large data set of 78 solar proton events observed near the Earth's orbit during 1996-2011 is investigated. An east-west longitudinal (azimuthal) asymmetry is found to exist in the distribution of flare sources of solar proton events. With the same longitudinal separation between the flare sources and the magnetic field line footpoint of observer, the number of the solar proton events originating from solar sources located on the eastern side of the nominal magnetic footpoint of observer is larger than the number of the solar proton events from solar sources located on the western side. We emphasize the importance of this statistical investigation in two aspects. On the one hand, this statistical finding confirms our previous simulation results obtained by numerically solving five-dimensional Fokker-Planck equation of solar energetic particle (SEP) transport. On the other hand, the east-west longitudinally (azimuthally) asymmetric distribution of solar proton events accumulated over a long time period provides an observational evidence for the effects of perpendicular diffusion on the SEP propagation in the heliosphere. We further point out that, in the sense of perpendicular diffusion, our numerical simulations and statistical results of SEP events confirm each other. We discuss in detail the important effects of perpendicular diffusion on the formation of the east-west azimuthal (longitudinal) asymmetry of SEP distribution in two physical scenarios, i.e. `multiple SEP events with one spacecraft' and `one SEP event with multiple spacecraft'. A functional relation Imax(r) = kr-1.7 quantifying the radial dependence of SEP peak intensities is obtained and utilized in the analysis of physical mechanism. The relationship between our results and those of Dresing et al. is also discussed.

  11. The Evolution of Al Qaeda

    DTIC Science & Technology

    2007-06-15

    www.carleton.ca/cciss/res_docs/itac/gendron_e.pdf; Internet. 26Muhammad Abd al-salam Faraj, Al-Farīdah al-Ghā’ibah, trans. Johannes J.G. Jansen and... Theo Van Gogh.91 Hoffman also supports the idea proposed by other experts like Benjamin Orbach and Keith Blanchard of the Congressional Research...religious intolerance over cartoons in Danish newspapers, the assassination of Theo Van Goeh, and increasing discontent among disassociated Muslim

  12. CSF neurofilament light chain reflects corticospinal tract degeneration in ALS

    PubMed Central

    Menke, Ricarda A L; Gray, Elizabeth; Lu, Ching-Hua; Kuhle, Jens; Talbot, Kevin; Malaspina, Andrea; Turner, Martin R

    2015-01-01

    Objective Diffusion tensor imaging (DTI) is sensitive to white matter tract pathology. A core signature involving the corticospinal tracts (CSTs) has been identified in amyotrophic lateral sclerosis (ALS). Raised neurofilament light chain protein (NfL) in cerebrospinal fluid (CSF) is thought to reflect axonal damage in a range of neurological disorders. The relationship between these two measures was explored. Methods CSF and serum NfL concentrations and DTI acquired at 3 Tesla on the same day were obtained from ALS patients (n = 25 CSF, 40 serum) and healthy, age-similar controls (n = 17 CSF, 25 serum). Within-group correlations between NfL and DTI measures of microstructural integrity in major white matter tracts (CSTs, superior longitudinal fasciculi [SLF], and corpus callosum) were performed using tract-based spatial statistics. Results NfL levels were higher in patients compared to controls. CSF levels correlated with clinical upper motor neuron burden and rate of disease progression. Higher NfL levels were significantly associated with lower DTI fractional anisotropy and increased radial diffusivity in the CSTs of ALS patients, but not in controls. Interpretation Elevated CSF and serum NfL is, in part, a result of CST degeneration in ALS. This highlights the wider potential for combining neurochemical and neuroimaging-based biomarkers in neurological disease. PMID:26273687

  13. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  14. Is there a paraneoplastic ALS?

    PubMed

    Corcia, Philippe; Gordon, Paul H; Camdessanche, Jean-Philippe

    2015-06-01

    Our objective was to examine the strength of evidence in support of the paraneoplastic syndrome (PNS) as one cause of ALS and, if the association appears more likely than chance, determine which features of ALS imply concurrent malignancy. We reviewed the literature on concurrent ALS and neoplasia assessing the strength of evidence for the association. Most accounts of ALS and neoplasm are case reports or small uncontrolled series. In order of strength of evidence, three clinical situations that support a paraneoplastic aetiology for ALS are: 1) laboratory evidence of well-characterized onconeuronal antibodies, most often anti-Hu, anti-Yo or anti-Ri; 2) co-occurrence of ALS and a neoplasm known to cause PNS, usually lymphoma or cancer of the breast; and 3) combined ALS and a neoplasm not classically associated with PNS, without detectable onconeuronal antibodies. Clinical features that warrant evaluation of neoplasm include upper motor neuron disease in elderly females, rapid progression, non-motor signs, and young onset. In conclusion, most examples of ALS and neoplasm do not constitute a classically established PNS. Rare instances of elevated onconeuronal antibody titres or typical neoplasm, implies that, albeit rare, the PNS is one of a multitude of causes of ALS.

  15. Understanding ALS: new therapeutic approaches.

    PubMed

    Musarò, Antonio

    2013-09-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease associated with motor neuron degeneration, muscle atrophy and paralysis. Although numerous pathological mechanisms have been elucidated, ALS remains an invariably fatal disease in the absence of any effective therapy. The heterogeneity of the disease and the failure to develop satisfactory therapeutic protocols reinforce the view that ALS is a multi-factorial and multi-systemic disease. Thus, a better understanding of the pathogenic mechanisms and study of the potential pathological relationship between the various cellular processes is required to ensure efficacious therapy. The pathogenic mechanisms associated with ALS are reviewed, and the strengths and limitations of some new therapeutic approaches are discussed.

  16. Changes in Left Ventricular Global and Regional Longitudinal Strain During Right Ventricular Pacing

    PubMed Central

    Algazzar, Alaa Solaiman; Katta, Azza Ali; Ahmed, Khaled Sayed; Elkenany, Nasima Mohamed; Ibrahim, Maher Abdelaleem

    2016-01-01

    Background Our study aimed to demonstrate the short-term impacts of right ventricular apical pacing (RVAP) and right ventricular septal pacing (RVSP) on left ventricular (LV) regional longitudinal strain (RLS) and global longitudinal strain (GLS) in patients with preserved ejection fraction (EF). LV strain and functions may be altered by RVAP. RVSP might be a better alternative. The detrimental effect of right ventricular (RV) pacing may be mediated by regional LV impairment. Methods Sixty-two patients indicated for permanent pacemaker implantation and preserved LV systolic function were included. Dual chamber pacemakers were implanted in all patients. Patients were divided into two groups according to RV lead position: group A (RVAP, n = 32) and group B (RVSP, n = 30). Patients were examined at baseline and after 6 months of implantation for LV systolic functions, global and regional strain by echocardiography and 2D speckle tracking echocardiography. Results Paced QRS duration was significantly shorter in group B compared to group A patients (P = 0.02). Regarding ventricular strain, there was no statistically significant difference between both groups at baseline measurements in comparisons of GLS, relative apical longitudinal strain (rALS) and RLS (P > 0.05). In contrast, there was statistically significant difference between both groups in results of GLS (P = 0.01) at 6 months. In addition, RLSs in septal, apical and rALS were affected after 6 months with P values of 0.02, 0.03 and 0.03, respectively. Conclusion RVAP appears to worsen GLS more than RVSP, and the resultant decrease in apical strain is most correlated region to decrease in GLS. PMID:28197264

  17. Longitudinal study examining the neurotoxicity of occupational exposure to aluminium-containing welding fumes.

    PubMed

    Buchta, M; Kiesswetter, E; Otto, A; Schaller, K H; Seeber, A; Hilla, W; Windorfer, K; Stork, J; Kuhlmann, A; Gefeller, O; Letzel, S

    2003-09-01

    The neurotoxicity of occupational exposure to aluminium (Al)-containing welding fumes has been discussed with controversial results. The aim of the longitudinal study was to examine a group of Al welders for significant central nervous changes in comparison with a non-exposed cohort. A group of 98 Al welders (mean age 37 years) in the car-body construction industry, with a median of 6 years of occupational exposure to Al welding fumes, and an education-matched, gender-matched, age-matched control group of 50 car-production workers (mean age 36 years) at the same plant, were included in this longitudinal study. Two cross-sectional studies were done in 1999 and 2001. In the second cross-sectional study 97 welders and 50 controls could be examined. The examination programme consisted, for example, of a standardised anamnesis, focussing on occupational history, education, illnesses, medication, accidents and current alcohol consumption, a physical examination that included neurological status, and the assessment of Al concentration in plasma and urine. The neurobehavioral methods included a symptom questionnaire, modified Q16, and computerised and non-computerised tests: psychomotor performance (steadiness, line tracing, aiming, tapping), verbal intelligence (WST), simple reaction time, digit span, block design (HAWIE), symbol-digit substitution, digit span, switching attention (European neurobehavioral evaluation system, EURO-NES), and standard progressive matrices. The data were analysed by multivariate analysis of covariance (MANCOVA) for repeated measurements with covariates age, education, and carbohydrate-deficient transferrin in plasma (CDT). RESULTS. The median Al urine concentration (mean preshift/postshift) was 52.4 microg/g creatinine (2001) and 57.6 microg/g creatinine (1999). Median respirable air dust was 0.67 mg/m(3) (2001) and 0.47 mg/m(3) (1999). Welders and controls did not report significantly more symptoms in the modified Q16. Furthermore, no

  18. Elasticity and inelasticity of the SiC/Al-13Si-9Mg biomorphic metal ceramics

    NASA Astrophysics Data System (ADS)

    Kardashev, B. K.; Orlova, T. S.; Smirnov, B. I.; Wilkes, T. E.; Faber, K. T.

    2008-10-01

    The acoustic investigations of the elastic (Young’s modulus) and microplastic properties of a composite material, the SiC/Al-13Si-9Mg biomorphic metal ceramic, were performed. The ceramic was prepared by infiltration of the Al-13Si-9Mg melt into porous silicon carbide derived from wood of two species of trees, beech and sapele. The measurements were performed with a composite piezoelectric vibrator under resonance conditions, with rod-shaped samples vibrated longitudinally at about 100 kHz over a wide range of vibrational strain amplitudes, which included both the linear (amplitude-independent) and nonlinear (microplastic) regions. It was shown that the Young’s modulus and the microplastic properties of the composite are anisotropic and depend substantially on the tree species, particularly when longitudinal vibrations are excited in samples cut along the tree fibers.

  19. Impurity Enhancement of Al_2O_3/Al Adhesion

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Smith, John R.; Zhang, Wenqing; Evans, Anthony

    2003-03-01

    Our first-principles computations indicate that the clean Al_2O_3/Al interface is relatively weak - weaker than bulk Al. Fracture experiments reveal that the interface is relatively strong with observed failure in bulk Al, however. This paradox is resolved via doping effects of the common impurity C. We have found that only 1/3 of a monolayer of carbon segregated to the interface can increase the work of separation by a factor of 3. The resulting strong interface is consistent with fracture experiments. It arises due to void formation in the interface, which provides low-strain sites for the carbon to segregate to. The degree of void formation is consistent with the relatively high heat of oxide formation of Al.

  20. Interfacial characterization of Al-Al thermocompression bonds

    SciTech Connect

    Malik, N.; Carvalho, P. A.; Poppe, E.; Finstad, T. G.

    2016-05-28

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO{sub 2} as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400–550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO{sub 2}. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO{sub 2}, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO{sub 2} are discussed.

  1. Longitudinal Muscle Dysfunction in Achalasia Esophagus and Its Relevance

    PubMed Central

    Hong, Su Jin; Bhargava, Valmik

    2013-01-01

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

  2. Longitudinal Stability of Common TMJ Structural Disorders.

    PubMed

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

    2017-03-01

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

  3. Climate and Conflict: A Comment on Hsiang et al.s Reply to Buhaug et al

    DTIC Science & Technology

    2014-01-01

    a wide range of climatic events, from heat waves via excess rainfall to global ENSO cycles; and a wide range of spatial scales, from municipalities...again analytical consistency; The Hsiang et al. (2011) study considers a global ENSO effect whereas the studies in the valid sample investigate a local...some of the studies described in Hsiang et al. (2013). Specifically, Buhaug et al. exclude the effects of ENSO and PDSI when estimating the aggregate

  4. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    NASA Astrophysics Data System (ADS)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-09-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  5. Explosive destruction of 26Al

    NASA Astrophysics Data System (ADS)

    Kahl, D.; Yamaguchi, H.; Shimizu, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Ge, Z.; Hayakawa, S.; Kwag, M. S.; Kim, D. H.; Moon, J. Y.; Park, S. Y.; Yang, L.

    2017-09-01

    The γ -ray emission associated with the radioactive decay of 26Al is one of the key pieces of observational evidence indicating stellar nucleosynthesis is an ongoing process in our Galaxy, and it was the first such radioactivity to be detected. Despite numerous efforts in stellar modeling, observation, nuclear theory, and nuclear experiment over the past four decades, the precise sites and origin of Galactic ^{26} Al remain elusive. We explore the present experimental knowledge concerning the destruction of ^{26} Al in massive stars. The precise stellar rates of neutron-induced reactions on ^{26} Al, such as (n,p) and (n, α , have among the largest impacts on the total ^{26} Al yield. Meanwhile, reactions involving the short-lived isomeric state of ^{26} Al such as radiative proton capture are highly-uncertain at present. Although we presented on-going experimental work from n_TOF at CERN with an ^{26} Al target, the present proceeding focuses only on the ^{26} Al isomeric radioactive beam production aspect and the first experimental results at CRIB.

  6. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    NASA Astrophysics Data System (ADS)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  7. Factors affecting longitudinal functional decline and survival in amyotrophic lateral sclerosis patients.

    PubMed

    Watanabe, Hazuki; Atsuta, Naoki; Nakamura, Ryoichi; Hirakawa, Akihiro; Watanabe, Hirohisa; Ito, Mizuki; Senda, Jo; Katsuno, Masahisa; Izumi, Yuishin; Morita, Mitsuya; Tomiyama, Hiroyuki; Taniguchi, Akira; Aiba, Ikuko; Abe, Koji; Mizoguchi, Kouichi; Oda, Masaya; Kano, Osamu; Okamoto, Koichi; Kuwabara, Satoshi; Hasegawa, Kazuko; Imai, Takashi; Aoki, Masashi; Tsuji, Shoji; Nakano, Imaharu; Kaji, Ryuji; Sobue, Gen

    2015-06-01

    Our objective was to elucidate the clinical factors affecting functional decline and survival in Japanese amyotrophic lateral sclerosis (ALS) patients. We constructed a multicenter prospective ALS cohort that included 451 sporadic ALS patients in the analysis. We longitudinally utilized the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) as the functional scale, and determined the timing of introduction of a tracheostomy for positive-pressure ventilation and death. A joint modelling approach was employed to identify prognostic factors for functional decline and survival. Age at onset was a common prognostic factor for both functional decline and survival (p < 0.001, p < 0.001, respectively). Female gender (p = 0.019) and initial symptoms, including upper limb weakness (p = 0.010), lower limb weakness (p = 0.008) or bulbar symptoms (p = 0.005), were related to early functional decline, whereas neck weakness as an initial symptom (p = 0.018), non-use of riluzole (p = 0.030) and proximal dominant muscle weakness in the upper extremities (p = 0.01) were related to a shorter survival time. A decline in the ALSFRS-R score was correlated with a shortened survival time (p < 0.001). In conclusion, the factors affecting functional decline and survival in ALS were common in part but different to some extent. This difference has not been previously well recognized but is informative in clinical practice and for conducting trials.

  8. Analysis of aircraft longitudinal handling qualities

    NASA Technical Reports Server (NTRS)

    Hess, R. A.

    1981-01-01

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

  9. A Longitudinal View of HTTP Traffic

    NASA Astrophysics Data System (ADS)

    Callahan, Tom; Allman, Mark; Paxson, Vern

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

  10. Parameter identification and modeling of longitudinal aerodynamics

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  11. Multivariate Longitudinal Modeling of Cognitive Aging

    PubMed Central

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

    2013-01-01

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

  12. Simulation of longitudinal coupled-bunch instabilities

    SciTech Connect

    Thompson, K.A.

    1991-02-07

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

  13. Longitudinal ultrasonic waves in DC electric field

    NASA Astrophysics Data System (ADS)

    Sobotka, Jerzy

    2009-06-01

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

  14. The longitudinal development of clusters in French.

    PubMed

    Demuth, Katherine; McCullough, Elizabeth

    2009-03-01

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

  15. Beam Tomography in Longitudinal Phase Space

    NASA Astrophysics Data System (ADS)

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

    1997-05-01

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

  16. Random-effects models for longitudinal data

    SciTech Connect

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

    1982-12-01

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

  17. Longitudinal predictors of high school completion.

    PubMed

    Barry, Melissa; Reschly, Amy L

    2012-06-01

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

  18. Longitudinal research on temperament in twins.

    PubMed

    Torgersen, A M

    1987-01-01

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

  19. Titan's sand seas of longitudinal dunes as indicators of winds and sediment transport

    NASA Astrophysics Data System (ADS)

    Radebaugh, J.; Lorenz, R. D.; Lunine, J. I.; Wall, S. D.; Spencer, C.; Kirk, R. L.; Lopes, R. M.; Stofan, E. R.; Allison, M.; Callahan, P.; Cassini RADAR Team

    2007-12-01

    The Cassini Titan Radar Mapper has revealed nearly ten thousand longitudinal dunes on the surface of Titan, mainly within +-30 deg latitude [1,2,3]. Based on dune orientations, divergence around topography, similarity to dune fields on Earth, and other features such as bright streaks, the prevailing wind hypothesis model for longitudinal dune formation is favored, in which winds blow generally parallel to the dune long axis [e.g.5,6,7]. On Titan, these winds are dominantly Eastward [2,3], but as observed in more recent Radar swaths (2,4,5/2007) there is Northeastward deviation from this direction at higher latitudes. Vast fields of longitudinal dunes at Titan's equatorial regions are described as sand seas [2,3]. On Earth, these regions are typified not so much by the transport as by the accumulation of sand. This may occur when there is a large nearby source of sand or when there is reduced sand removal due to decreased winds or topographic obstacles [7,8,9]. Sand transport could be inhibited both upwind and downwind of the topographically complex region Xanadu, for example. Seasonally reversing wind regimes could also lead to the stagnation of sand transportation and net accumulation within sand sea regions [7,8,9]. This scenario may help reconcile global wind model predictions with directionality opposed to that predicted from observation. Sand seas on Earth are formed in arid regions and in some places cover 30-40 percent of the surface [8], a percent coverage similar to that in the equatorial regions on Titan [2,3]. Sand seas on Earth are long-lived, having taken up to tens of thousands of years to accumulate; whether the Titan dunes are more or less stable is an outstanding question. [1] Elachi et al. 2006. [2] Lorenz et al. 2006. [3] Radebaugh et al. in rev. [4] Stofan et al. 2007. [5] Fryberger and Dean 1979. [6] Tsoar 1983. [7] Lancaster 1982. [8] Lancaster 1995. [9] Fryberger and Ahlbrandt 1979.

  20. A Longitudinal Study of Adolescent Adjustment Following Family Transitions

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  1. Longitudinal and transverse mode evolution in free electron laser

    SciTech Connect

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

    1995-12-31

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

  2. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  3. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  4. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  5. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  6. 14 CFR 23.173 - Static longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  9. The estimate and measurement of longitudinal wave intensity

    NASA Astrophysics Data System (ADS)

    Ruisen, Ming

    1996-08-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Vanderstaay, Steven L.

    2006-01-01

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

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

    ERIC Educational Resources Information Center

    Davis, J. A.; Collins, Elmer

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

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

    ERIC Educational Resources Information Center

    Vanderstaay, Steven L.

    2006-01-01

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

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

    ERIC Educational Resources Information Center

    Meeus, Wim

    2016-01-01

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

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

    ERIC Educational Resources Information Center

    Seo, Dong-Chul; Li, Kaigang

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Davis, J. A.; Collins, Elmer

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

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

    ERIC Educational Resources Information Center

    Meeus, Wim

    2016-01-01

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

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

    ERIC Educational Resources Information Center

    Hall, Gene E.

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

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

    ERIC Educational Resources Information Center

    Chen, Pan; Vazsonyi, Alexander T.

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Seo, Dong-Chul; Li, Kaigang

    2012-01-01

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

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

    ERIC Educational Resources Information Center

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

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Judge, Sharon; Watson, Silvana M. R.

    2011-01-01

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

  5. Longitudinal Predictors of Very Early Chinese Literacy Acquisition

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  6. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  7. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  8. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  9. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  10. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Hall, Gene E.

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

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

    ERIC Educational Resources Information Center

    Cernat, Alexandru

    2015-01-01

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

  14. Van Kampen modes for bunch longitudinal motion

    SciTech Connect

    Burov, A.; /Fermilab

    2010-09-01

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

  15. Longitudinal patient-oriented outcomes in neuropathy

    PubMed Central

    Kerber, Kevin; Langa, Kenneth M.; Banerjee, Mousumi; Rodgers, Ann; McCammon, Ryan; Burke, James; Feldman, Eva

    2015-01-01

    Objective: To evaluate longitudinal patient-oriented outcomes in peripheral neuropathy over a 14-year time period including time before and after diagnosis. Methods: The 1996–2007 Health and Retirement Study (HRS)–Medicare Claims linked database identified incident peripheral neuropathy cases (ICD-9 codes) in patients ≥65 years. Using detailed demographic information from the HRS and Medicare claims, a propensity score method identified a matched control group without neuropathy. Patient-oriented outcomes, with an emphasis on self-reported falls, pain, and self-rated health (HRS interview), were determined before and after neuropathy diagnosis. Generalized estimating equations were used to assess differences in longitudinal outcomes between cases and controls. Results: We identified 953 peripheral neuropathy cases and 953 propensity-matched controls. The mean (SD) age was 77.4 (6.7) years for cases, 76.9 (6.6) years for controls, and 42.1% had diabetes. Differences were detected in falls 3.0 years before neuropathy diagnosis (case vs control; 32% vs 25%, p = 0.008), 5.0 years for pain (36% vs 27%, p = 0.002), and 5.0 years for good to excellent self-rated health (61% vs 74%, p < 0.0001). Over time, the proportion of fallers increased more rapidly in neuropathy cases compared to controls (p = 0.002), but no differences in pain (p = 0.08) or self-rated health (p = 0.9) were observed. Conclusions: In older persons, differences in falls, pain, and self-rated health can be detected 3–5 years prior to peripheral neuropathy diagnosis, but only falls deteriorates more rapidly over time in neuropathy cases compared to controls. Interventions to improve early peripheral neuropathy detection are needed, and future clinical trials should incorporate falls as a key patient-oriented outcome. PMID:26019191

  16. Longitudinal changes in lung hyperinflation in COPD

    PubMed Central

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

    2017-01-01

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

  17. Longitudinal gradients along a reservoir cascade

    USGS Publications Warehouse

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

    2008-01-01

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

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

    PubMed

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

    2002-11-01

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

  19. Distraction osteogenesis using a longitudinal corticotomy.

    PubMed

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

    2012-05-01

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

  20. HARVEST, a longitudinal patient record summarizer

    PubMed Central

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

    2015-01-01

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

  1. Prospective, longitudinal assessment of developmental neurotoxicity.

    PubMed Central

    Jacobson, J L; Jacobson, S W

    1996-01-01

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

  2. Onset of magnetic correlations in CeAl/sub 3/ below 2 K

    SciTech Connect

    Barth, S.; Ott, H.R.; Gygax, F.N.; Hitti, B.; Lippelt, E.; Schenck, A.; Baines, C.; van den Brandt, B.; Konter, T.; Mango, S.; and others

    1987-12-28

    The results of zero-, transverse-, and longitudinal-field muon-spin rotationmeasurements in polycrystalline CeAl/sub 3/ are reported. They provide evidence for static magnetic correlations in CeAl/sub 3/ below 2 K. From the magnitude of the local magnetic field at the muon site it was estimated that the effective Ce/sup 3+/ moments may be of the order of 0.05..mu../sub B/. The magnetic correlations appear as a spatially inhomogeneous phenomenon, and are partly coherent below 0.7 K. No evidence for a cooperative phase transition is found.

  3. Ultrafine-grained structure formation in Ti-6Al-4V alloy via warm swaging

    NASA Astrophysics Data System (ADS)

    Klimova, M.; Boeva, M.; Zherebtsov, S.; Salishchev, G.

    2014-08-01

    The influence of warm swaging on the structure and properties of Ti-6Al-4V alloy was studied. Warm swaging of the alloy in the interval 680-500°C with the total strain of ɛ=2.66 was found to be resulted in the formation of a homogeneous globular microstructure with a grain size of 0.4 μm in both longitudinal and transversal sections. Room temperature tensile strength and tensile elongation of the swaged alloy was 1315MPa and 10.5%, respectively. Ultrafine-grained Ti-6Al-4V alloy produced by swaging exhibited good workability at 600-700 °C.

  4. Roadmap and standard operating procedures for biobanking and discovery of neurochemical markers in ALS.

    PubMed

    Otto, Markus; Bowser, Robert; Turner, Martin; Berry, James; Brettschneider, Johannes; Connor, James; Costa, Júlia; Cudkowicz, Merit; Glass, Jonathan; Jahn, Olaf; Lehnert, Stefan; Malaspina, Andrea; Parnetti, Lucilla; Petzold, Axel; Shaw, Pamela; Sherman, Alexander; Steinacker, Petra; Süssmuth, Sigurd; Teunissen, Charlotte; Tumani, Hayrettin; Wuolikainen, Anna; Ludolph, Albert

    2012-01-01

    Despite major advances in deciphering the neuropathological hallmarks of amyotrophic lateral sclerosis (ALS), validated neurochemical biomarkers for monitoring disease activity, earlier diagnosis, defining prognosis and unlocking key pathophysiological pathways are lacking. Although several candidate biomarkers exist, translation into clinical application is hindered by small sample numbers, especially longitudinal, for independent verification. This review considers the potential routes to the discovery of neurochemical markers in ALS, and provides a consensus statement on standard operating procedures that will facilitate multicenter collaboration, validation and ultimately clinical translation.

  5. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  6. PREDICTING NORMATIVE AND PROBLEMATIC FAMILY PATHWAYS TO THE TRANSITION TO SIBLINGHOOD: COMMENTARY ON VOLLING ET AL.'S MONOGRAPH.

    PubMed

    Howe, Nina

    2017-09-01

    Volling et al.'s monograph provides a rich, thoughtful, and rigorous account of how the transition to siblinghood is experienced by the first-born child and the family. In their comprehensive longitudinal study, they followed 241 families from the prenatal period before the second-born's birth until this child was 12-months old. Siblings are a critical, but understudied, relationship in children's development; the challenges posed in researching sibling dynamics in the context of the family are discussed. Prior psychodynamic and developmental research literature is critiqued, which places the current study into perspective and indicates the important theoretical frameworks (i.e., developmental psychopathology and developmental ecological systems) employed by Volling et al. to advance our understanding of this critical transition in the life of the family. The longitudinal study design, sample characteristics, identification of possible trajectories of adjustment (or not) to the birth of the sibling, and selection of family and child variables are addressed. The sophisticated statistical methods (Growth Mixture Modeling and data mining procedures) employed to predict child adjustment in association with parenting variables over time and sibling relationship quality at 12 months identified low- and high-risk trajectories on the seven subscales of the Child Behavior Check List (CBCL). This afforded a nuanced investigation of a variety of potentially problematic child behaviors (e.g., aggression, withdrawal, negative emotionality, somatic problems) in association with parenting behaviors. A final discussion included study limitations, significant strengths, and implications for clinicians and other professionals. The study's conclusion is that most children and families are resilient, take the birth of a sibling in their stride, and do not exhibit empirical evidence of a developmental crisis, as argued by earlier psychodynamic authors. © 2017 The Society for Research

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

    PubMed

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

    2016-09-01

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

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

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

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

  9. 78 FR 44553 - Agency Information Collection Activities; Comment Request; Early Childhood Longitudinal Study...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

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

  10. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  11. Fabrication and Analysis of the Wear Properties of Hot-Pressed Al-Si/SiCp + Al-Si-Cu-Mg Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Bang, Jeongil; Oak, Jeong-Jung; Park, Yong Ho

    2016-01-01

    The aim of this study was to characterize microstructures and mechanical properties of aluminum metal matrix composites (MMC's) prepared by powder metallurgy method. Consolidation of mixed powder with gas atomized Al-Si/SiCp powder and Al-14Si-2.5Cu-0.5Mg powder by hot pressing was classified according to sintering temperature and sintering time. Sintering condition was optimized using tensile properties of sintered specimens. Ultimate tensile strength of the optimized sintered specimen was 228 MPa with an elongation of 5.3% in longitudinal direction. In addition, wear properties and behaviors of the sintered aluminum-based MMC's were analyzed in accordance with vertical load and linear speed. As the linear speed and vertical load of the wear increased, change of the wear behavior occurred in order of oxidation of Al-Si matrix, formation of C-rich layer, Fe-alloying to matrix, and melting of the specimen

  12. Combining group-based trajectory modeling and propensity score matching for causal inferences in nonexperimental longitudinal data.

    PubMed

    Haviland, Amelia; Nagin, Daniel S; Rosenbaum, Paul R; Tremblay, Richard E

    2008-03-01

    A central theme of research on human development and psychopathology is whether a therapeutic intervention or a turning-point event, such as a family break-up, alters the trajectory of the behavior under study. This article describes and applies a method for using observational longitudinal data to make more transparent causal inferences about the impact of such events on developmental trajectories. The method combines 2 distinct lines of research: work on the use of finite mixture modeling to analyze developmental trajectories and work on propensity score matching. The propensity scores are used to balance observed covariates and the trajectory groups are used to control pretreatment measures of response. The trajectory groups also aid in characterizing classes of subjects for which no good matches are available. The approach is demonstrated with an analysis of the impact of gang membership on violent delinquency based on data from a large longitudinal study conducted in Montréal, Canada.

  13. Longitudinal phase space tomography with space charge

    NASA Astrophysics Data System (ADS)

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

    2000-12-01

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

  14. Longitudinal determinants of substance use disorders.

    PubMed

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

    2013-12-01

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

  15. Reply to Gopalswamy et al.

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.

    2003-01-01

    The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

  16. In memory of Al Cameron

    NASA Astrophysics Data System (ADS)

    Cowan, John; Truran, James W.

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning ele- ment formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

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

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Yang, Zhigang; Collu, Maurizio

    2015-06-01

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

  18. Time Resolved Imaging of Longitudinal Modulations in Intense Beams

    NASA Astrophysics Data System (ADS)

    Tian, Kai

    2007-11-01

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

  19. Al-Co-Fe (030)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Co-Fe (030)' with the content:

  20. Al-La-Nb (068)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Nb (068)' with the content:

  1. Al-Cu-Zr (050)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Cu-Zr (050)' with the content:

  2. Al-La-Ni (069)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Ni (069)' with the content:

  3. Al-Au-La (010)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Au-La (010)' with the content:

  4. Al-Ce-V (029)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Ce-V (029)' with the content:

  5. ALS: focus on purinergic signalling.

    PubMed

    Volonté, Cinzia; Apolloni, Savina; Carrì, Maria Teresa; D'Ambrosi, Nadia

    2011-10-01

    Amyotrophic lateral sclerosis (ALS) is one of the most common neuromuscular diseases. It is devastating and fatal, causing progressive paralysis of all voluntary muscles and eventually death, while sparing cognitive functions. A pathological hallmark of ALS is neuroinflammation mediated by non-neuronal cells in the nervous system, such as microglia and astrocytes that accelerate the disease progression. Scientists have neither found a unique key mechanism, nor an effective treatment against ALS, supposedly because it is a multi-factorial and multi-systemic disease. Extracellular purines and pyrimidines are widespread and powerful physiopathological molecules, signalling to most cell types and directing cell-to-cell communication networks. They are instrumental for instance for neurotransmission, muscle contraction and immune surveillance. Recent work has reported the crucial involvement of purinergic pathways in many neurodegenerative and neuroinflammatory diseases, comprising ALS. Especially P2 receptors for ATP, P1 receptors for adenosine, and nucleotide transporters were found to be modulated in ALS cells and tissues, playing a potential role in the disease. Given the composite cellular cross-talk occurring during ALS and the established action of extracellular purines/pyrimidines as neuron-to-glia alarm signal in the nervous system, a mutual query in these two fields should now be whether, how and when purinergic would meet ALS. In this review, we will highlight the early cellular and molecular purinergic cross-talk that participates to ALS etiopathology, with the conviction that better understanding of purinergic dynamics might provide original research perspectives, stimulate alternative disease modelling, and the design and testing of more powerful targeted therapeutics against this relentlessly progressive disorder. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Longitudinal vibration of cracked beams under magnetic field

    NASA Astrophysics Data System (ADS)

    Güven, Uğur

    2016-12-01

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

  7. Longitudinal emittance growth due to nonlinear space charge effect

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

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

    SciTech Connect

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

    2007-11-01

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

  9. Multiplexed multi-longitudinal mode fiber laser sensor.

    PubMed

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

    2014-10-20

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

  10. Signal processing for longitudinal parameters of the Tevatron beam

    SciTech Connect

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

    2005-05-01

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

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

    SciTech Connect

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

    2005-05-25

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

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

    PubMed

    Liu, Mengling; Lu, Wenbin

    2012-01-01

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

  13. Io: longitudinal distribution of sulfur dioxide frost.

    PubMed

    1980-11-14

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

  14. Longitudinal Relationships Between Resources, Motivation, and Functioning

    PubMed Central

    Emery, Lisa; Neupert, Shevaun D.

    2012-01-01

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

  15. Longitudinal validation of psychosis risk screening tools.

    PubMed

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

    2015-07-01

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

  16. SORL1 predicts longitudinal cognitive change

    PubMed Central

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

    2013-01-01

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

  17. Longitudinal maxillary growth in Down syndrome patients.

    PubMed

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

    2011-03-01

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

  18. Longitudinal performance of an implantable vestibular prosthesis

    PubMed Central

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

    2014-01-01

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

  19. Adolescent stress and coping: a longitudinal study.

    PubMed

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

    1992-06-01

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

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

    PubMed

    Sastre-Riba, S

    2009-02-27

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

  1. Longitudinal dynamic stability of a shuttle vehicle.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  2. Longitudinal wheel slip during ABS braking

    NASA Astrophysics Data System (ADS)

    Hartikainen, Lassi; Petry, Frank; Westermann, Stephan

    2015-02-01

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

  3. Dual imputation model for incomplete longitudinal data.

    PubMed

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

    2014-05-01

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

  4. Longitudinal Waves Organize and Control Plants

    NASA Astrophysics Data System (ADS)

    Wagner, Orvin

    2002-03-01

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

  5. Automatic parcellation of longitudinal cortical surfaces

    NASA Astrophysics Data System (ADS)

    Alassaf, Manal H.; Hahn, James K.

    2015-03-01

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

  6. NASA Planetary Science Summer School: Longitudinal Study

    NASA Astrophysics Data System (ADS)

    Giron, Jennie M.; Sohus, A.

    2006-12-01

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

  7. Analysis of critically refracted longitudinal waves

    NASA Astrophysics Data System (ADS)

    Pei, Ning; Bond, Leonard J.

    2015-03-01

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

  8. Analysis of critically refracted longitudinal waves

    SciTech Connect

    Pei, Ning Bond, Leonard J.

    2015-03-31

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

  9. Heat transfer in a longitudinal glow discharge

    NASA Astrophysics Data System (ADS)

    Yunusov, R. F.

    2017-01-01

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

  10. Semiparametric Bayesian classification with longitudinal markers

    PubMed Central

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

    2013-01-01

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

  11. Longitudinal dynamics of a perching aircraft concept

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim; Waszak, Martin

    2005-05-01

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

  12. Longitudinal growth in chronic hypokalemic disorders.

    PubMed

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

    2010-04-01

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

  13. Cuba's Aging and Alzheimer Longitudinal Study.

    PubMed

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

    2017-01-01

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

  14. Personality and Smoking Status: A Longitudinal Analysis

    PubMed Central

    Munafó, Marcus R.; Black, Stephanie

    2007-01-01

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

  15. Longitudinal variability of black carbon vertical profiles

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  16. Sortilin receptor 1 predicts longitudinal cognitive change.

    PubMed

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

    2013-06-01

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

  17. Laser Wakefield diagnostic using holographic longitudinal interferometry

    SciTech Connect

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

    1999-03-26

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

  18. Longitudinal performance of an implantable vestibular prosthesis.

    PubMed

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

    2015-04-01

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

  19. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

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

    PubMed

    Farcomeni, Alessio; Viviani, Sara

    2015-03-30

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

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

    PubMed

    Tong, Jasper W K; Kong, Pui W

    2016-08-01

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

  2. Friction Stir Brazing: a Novel Process for Fabricating Al/Steel Layered Composite and for Dissimilar Joining of Al to Steel

    NASA Astrophysics Data System (ADS)

    Zhang, Guifeng; Su, Wei; Zhang, Jianxun; Wei, Zhongxin

    2011-09-01

    A novel process of friction stir brazing (FSB) for fabricating Al/steel layered composite (by multipass) and for joining Al to steel (by single pass) was proposed to avoid the wear of pin by steel, in which a tool without pin was used. FSB of 1.8-mm-thick Al sheet to steel sheet was conducted using a cylindrical tool with 20-mm diameter but without pin and using 0.1-mm-thick zinc foil as filler metal. For the rotational speed of 1500 rpm, sound joints were reliably obtained at the medium range of traverse speed of 75 to 235 mm/min, which fractured within Al parent sheet during tensile shear test. Furthermore, for peel test on the sound joints, Al and steel parent sheets tended to crack and deform, respectively. Metallographic examination showed that most Zn was extruded and the resultant interfacial structure consisted of several Al-Fe intermetallic compounds (IMCs) with a little Zn, less than 3 at. pct. The thickness of IMCs can be controlled to be less than 10 μm by properly increasing traverse speed ( e.g., 150 mm/min). The metallurgical process of FSB was investigated by observing the microstructure of the longitudinal section of a friction stir brazed joint obtained by the suddenly stopping technique.

  3. Semiparametric estimation of time-dependent ROC curves for longitudinal marker data.

    PubMed

    Zheng, Yingye; Heagerty, Patrick J

    2004-10-01

    One approach to evaluating the strength of association between a longitudinal marker process and a key clinical event time is through predictive regression methods such as a time-dependent covariate hazard model. For example, a Cox model with time-varying covariates specifies the instantaneous risk of the event as a function of the time-varying marker and additional covariates. In this manuscript we explore a second complementary approach which characterizes the distribution of the marker as a function of both the measurement time and the ultimate event time. Our goal is to extend the standard diagnostic accuracy concepts of sensitivity and specificity so as to recognize explicitly both the timing of the marker measurement and the timing of disease. The accuracy of a longitudinal marker can be fully characterized using time-dependent receiver operating characteristic (ROC) curves. We detail a semiparametric estimation method for time-dependent ROC curves that adopts a regression quantile approach for longitudinal data introduced by Heagerty and Pepe (1999, Applied Statistics, 48, 533-551). We extend the work of Heagerty and Pepe (1999, Applied Statistics, 48, 533-551) by developing asymptotic distribution theory for the ROC estimators where the distributional shape for the marker is allowed to depend on covariates. To illustrate our method, we analyze pulmonary function measurements among cystic fibrosis subjects and estimate ROC curves that assess how well the pulmonary function measurement can distinguish subjects that progress to death from subjects that remain alive. Comparing the results from our semiparametric analysis to a fully parametric method discussed by Etzioni et al. (1999, Medical Decision Making, 19, 242-251) suggests that the ability to relax distributional assumptions may be important in practice.

  4. Introduction to longitudinal data analysis in psychiatric research.

    PubMed

    Liu, Xian

    2015-08-25

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

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

    ERIC Educational Resources Information Center

    Magnusson, D.; Backteman, G.

    1979-01-01

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

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

    PubMed

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

    2015-04-01

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

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

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

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

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

    PubMed

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

    2009-05-01

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

  9. Multivariate longitudinal data analysis with mixed effects hidden Markov models.

    PubMed

    Raffa, Jesse D; Dubin, Joel A

    2015-09-01

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

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

    PubMed

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

    2016-04-04

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

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

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

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

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

    EPA Science Inventory

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

  13. New design of longitudinal ultrasonic vibrator for wire drawing

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    ERIC Educational Resources Information Center

    Inkelas, Sharon

    2003-01-01

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

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

    SciTech Connect

    King-Yuen Ng

    1998-10-01

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

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

    EPA Science Inventory

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

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

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

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

  2. Viability of longitudinal trenches for capturing contaminated groundwater.

    PubMed

    Hudak, Paul F

    2010-04-01

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

  3. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K. E-mail: yadav.satyesh@gmail.com Liu, X.-Y. E-mail: yadav.satyesh@gmail.com; Wang, J.

    2016-06-14

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. The formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  4. Development of Laser Fabricated Ti-6Al-4V

    NASA Technical Reports Server (NTRS)

    deGroh, Henry C., III

    2006-01-01

    Laser Engineered Net Shaping (LENS) depositions with Ti-6Al-4V gas-atomized powder were accomplished at five different temperatures, ranging from 30 to 400 C, imposed on the base plate. These base plate temperatures were employed in an effort to relieve stresses which develop during the deposition. Warpage of the base plate was monitored. Only a slight decline in warpage was observed as the base plate temperature was increased. Results indicate that substrate temperatures closer to the stress relief minimum of 480 C would relieve deposition stresses, though process parameters would likely need to be modified to compensate for the higher base plate temperature. The compositions of the as-received powder and the LENS deposited material were chemically analyzed. The oxygen content of the LENS material was 0.154 wt.% which is less than the maximum impurity limit of 0.2 percent for commercial Ti-6Al-4V alloys, but is over the limit allowed in ELI grade (0.13 percent). The level of oxygen in the commercial base plate used was only 0.0635 percent. Tensile specimens were machined from the LENS deposited material and tested in tension at room temperature. The ultimate and yield tensile stresses of the LENS material were about 1200 and 1150 MPa respectively, which is about 20 percent higher than the strengths of wrought Ti-6Al-4V. The higher strength of the LENS material was due to its fine structure and high oxygen content. The LENS deposits were not fully dense; voids were frequent at the interfaces between deposited layers. These dispersed sheets of voids were parallel to the longitudinal axis of the resulting tensile specimens. Apparently there was sufficient continuous, fully dense material longitudinally to enable the high strengths. Ductility was low in the LENS material. Percent elongation at failure in the LENS material was near 4 percent, which is less than half of what is usually expected from Ti-6Al-4V. The low ductility was caused by high oxygen levels, and the

  5. A Longitudinal Investigation of Race, Socioeconomic Status, and Psychosocial Mediators of Allostatic Load in Midlife Women: Findings from the Study of Women’s Health Across the Nation

    PubMed Central

    Upchurch, Dawn M.; Stein, Judith; Greendale, Gail A.; Chyu, Laura; Tseng, Chi-Hong; Huang, Mei-Hua; Lewis, Tené T.; Kravitz, Howard M.; Seeman, Teresa

    2015-01-01

    Objectives This research sought to assess racial and SES differences in level and change in allostatic load (AL) over time in midlife women and to test whether psychosocial factors mediate these relationships. These factors were: discrimination, perceived stress, and hostility. Methods Longitudinal data obtained from the Study of Women’s Health Across the Nation SWAN were used (n = 2063; mean age at baseline = 46.0). Latent growth curve (LGC) models evaluated the impact of demographic, menopausal, and psychosocial variables on level and change in AL over 8 years. Results Direct effects: High levels of discrimination and hostility significantly predicted higher AL (path coefficients 0.05, 0.05 respectively). High perceived stress significantly predicted a faster rate of increase of AL (path coefficient 0.06). Racial and socioeconomic status (SES) differentials were present, with African American race (path coefficient 0.23), low income (path coefficient −0.15), and low education (path coefficient −0.08) significantly predicted high AL level. Indirect effects: Significant indirect effects were found for African American race, less income, and lower education through higher discrimination, perceived stress, and hostility on level and rate of AL. Conclusion This was one of the first studies that investigated AL over multiple time periods and results supported AL as a cumulative phenomenon, affected by multiple psychosocial and demographic factors. The results suggest the complex ways in which race, SES, and psychosocial factors operate to influence AL. PMID:25886828

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

    SciTech Connect

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

    2010-12-01

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

  7. Simultaneous maximum a posteriori longitudinal PET image reconstruction

    NASA Astrophysics Data System (ADS)

    Ellis, Sam; Reader, Andrew J.

    2017-09-01

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

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

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1972-01-01

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

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

    PubMed

    Gundes, Hakan; Tosun, Bilgehan

    2005-09-01

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

  10. Longitudinal dispersion modeling in small streams

    NASA Astrophysics Data System (ADS)

    Pekarova, Pavla; Pekar, Jan; Miklanek, Pavol

    2014-05-01

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

  11. Benefits for Military Veterans with ALS

    MedlinePlus

    ... and Caregivers Newly Diagnosed Clinical Trials Familial ALS Military Veterans For Caregivers Resources Read stories from families living with ALS ALS Registry Augmentative Communication Site Map | Press Room | FAQ | Policies | RSS | Contact ...

  12. Traveltime and longitudinal dispersion in Illinois streams

    USGS Publications Warehouse

    Graf, Julia B.

    1986-01-01

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

  13. Longitudinal Association of Dementia and Depression

    PubMed Central

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

    2015-01-01

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

  14. Longitudinal Association of Dementia and Depression.

    PubMed

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

    2015-09-01

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

  15. Longitudinal associations between reading and mathematics achievement.

    PubMed

    Grimm, Kevin J

    2008-01-01

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

  16. Longitudinal Diffusion Tensor Imaging in Frontotemporal Dementia

    PubMed Central

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

    2015-01-01

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

  17. Longitudinal respiratory studies in older people

    PubMed Central

    Milne, J S

    1978-01-01

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

  18. Design study of 15-Tesla RHQT Nb3Al block type dipole magnet

    SciTech Connect

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    The design study of the block type 15-Tesla RHQT Nb{sub 3}Al dipole magnet, and its merits over Nb{sub 3}Sn magnets are presented. The copper stabilized RHQT Nb{sub 3}Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb{sub 3}Al strand with filament size about 50 {mu}, non-copper Jc about 1000 A/mm{sup 2} at 15 Tesla at 4.2K, copper ratio of 50%, can now be produced over several hundred meters. The stress and strain characteristics of the Nb{sub 3}Al strand are superior to the Nb{sub 3}Sn strand. Another advantage is that it can tolerate a longitudinal strain up to 0.55%. The RHQT Nb{sub 3}Al Rutherford cable will have less chance of contamination of the stabilizer, compared to Nb{sub 3}Sn cable. These characteristics of the RHQT Nb{sub 3}Al will be beneficial for designing and producing 15-Tesla dipole magnets. An example 15-Tesla magnet cross section, utilizing the RHQT Nb{sub 3}Sn strand is presented. A systematic investigation on RHQT Nb{sub 3}Al strands, its Rutherford cables, and building a small racetrack magnet for cable testing are proposed.

  19. Multidimensional latent trait linear mixed model: an application in clinical studies with multivariate longitudinal outcomes.

    PubMed

    Wang, Jue; Luo, Sheng

    2017-09-10

    Multilevel item response theory (MLIRT) models have been widely used to analyze the multivariate longitudinal data of mixed types (e.g., categorical and continuous) in clinical studies. The MLIRT models often have unidimensional assumption, that is, the multiple outcomes are clinical manifestations of a univariate latent variable. However, the unidimensional assumption may be unrealistic because some diseases may be heterogeneous and characterized by multiple impaired domains with variable clinical symptoms and disease progressions. We relax this assumption and propose a multidimensional latent trait linear mixed model (MLTLMM) to allow multiple latent variables and within-item multidimensionality (one outcome can be a manifestation of more than one latent variable). We conduct extensive simulation studies to assess the unidimensional MLIRT model and the proposed MLTLMM model. The simulation studies suggest that the MLTLMM model outperforms unidimensional model when the multivariate longitudinal outcomes are manifested by multiple latent variables. The proposed model is applied to two motivating studies of amyotrophic lateral sclerosis: a clinical trial of ceftriaxone and the Pooled Resource Open-Access ALS Clinical Trials database. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Ethnic Identity, Bicultural Identity Integration, and Psychological Well-Being Among Transracial Adoptees: A Longitudinal Study.

    PubMed

    Ferrari, Laura; Rosnati, Rosa; Manzi, Claudia; Benet-Martínez, Verònica

    2015-12-01

    The ethnic identity development plays a crucial role in adolescence and emerging adulthood and may be more complex for adoptees who do not share their ethnic identity with their adoptive families. Evidence from the studies was mixed, with strong ethnic identity not always found to be indicative of improved psychological adjustment. Recently research carried out on ethnic minorities has highlighted that the relation between ethnic identity and well-being could be influenced by Bicultural Identity Integration (BII) (Benet-Martínez et al., 2002): It reflects how individuals who experience more than one culture organize and combine their dual cultural backgrounds. These results are consistent also among adoptees (Manzi, Ferrari, Rosnati, & Benet-Martínez, 2013) but need to be further explored. A longitudinal study was conducted to investigate whether and the extent to which ethnic identity, national identity, and BII are protective factors for adoptees' psychological well-being. A self-report questionnaire was administered to 79 Italian transracial adoptees, aged between 15 and 25, at two time points, one year apart. In line with predictions, longitudinal analyses showed the crucial role of BII that turned out to increase higher levels of well-being one year later. Results are discussed in relation to implications for intervention with adoptive parents and children. © 2015 Wiley Periodicals, Inc.

  1. Ten-year longitudinal trajectories of older adults' basic and everyday cognitive abilities.

    PubMed

    Yam, Anna; Gross, Alden L; Prindle, John J; Marsiske, Michael

    2014-11-01

    To examine the longitudinal trajectories of everyday cognition and longitudinal associations with basic (i.e., laboratory and experimentally measured) cognitive abilities, including verbal memory, inductive reasoning, visual processing speed, and vocabulary. Participants were healthy older adults drawn from the no-treatment control group (N = 698) of the Advanced Cognitive Training for the Independent and Vital Elderly (Willis et al., 2006) randomized trial and were assessed at baseline and 1, 2, 3, 5, and 10 years later. Analyses were conducted using latent growth models. Modeling revealed an overall inverted-U shape (quadratic) trajectory across cognitive domains. Among basic cognitive predictors, level and slope in reasoning demonstrated the closest association to level and slope of everyday cognition, and accounted for most of the individual differences in linear gain in everyday cognition. Everyday cognition is not buffered against decline, and is most closely related to inductive reasoning in healthy older adults. To establish the clinical utility of everyday cognitive measures, future research should examine these associations in samples with more cognitive impairment. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  2. Longitudinal analysis of deciduous tooth emergence: III. Sexual dimorphism in Bangladeshi, Guatemalan, Japanese, and Javanese children.

    PubMed

    Holman, Darryl J; Jones, Robert E

    2003-11-01

    Previous studies, mostly in European populations, found sex differences in the pattern of deciduous tooth emergence. Most studies find that the anterior dentition in males is precocial relative to the female dentition, and the pattern reverses so that females lead males in the emergence of the posterior deciduous dentition. Less is known about sex differences in the dental development and emergence of non-European populations. Here we examine the pattern of sex differences in deciduous tooth emergence in Japanese, Javanese, Guatemalan, and Bangladeshi children. The data come from four longitudinal or mixed longitudinal studies using similar study protocols. Survival analysis was used to estimate parameters of a log-normal distribution of emergence for each of the 10 teeth of the left dentition, and sexual dimorphism was assessed by sex-specific differences in mean emergence times and by Bennett's index. The results support the pattern of developmental cross-over observed in other populations. We conclude that there is little evidence to support the hypothesis of Tanguay et al. ([1984] J. Dent. Res. 63:65-68) that ethnic factors mediate sex differences in the emergence of deciduous teeth. Copyright 2003 Wiley-Liss, Inc.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-12-01

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

  5. Modeling Longitudinal Data Containing Non-Normal Within Subject Errors

    NASA Technical Reports Server (NTRS)

    Feiveson, Alan; Glenn, Nancy L.

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Jakubczyk, Pawel; Metzner, Walter

    2017-02-01

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

  7. Joint Analysis of Survival Time and Longitudinal Categorical Outcomes

    PubMed Central

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

    2013-01-01

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

  8. Response to Zambon et al.

    PubMed

    Laplante, Caroline; Pollard, Thomas D

    2017-02-06

    Stimulated by our 2015 Current Biology paper [1], Zambon et al. reinvestigated how three myosin isoforms participate in the formation and constriction of the contractile ring in fission yeast. Our paper presented evidence that these myosin isoforms have distinct roles: "Conventional myosin-II Myo2 is crucial to ring assembly, unconventional myosin-II Myp2 is most important for ring constriction, and type V myosin Myo51 aids the other two myosins." Zambon et al. used different markers to reexamine the contributions of the three myosins to cytokinesis and concluded "that Myo2p is the major motor involved in ring contraction in S. pombe." Here, we show that most of the differences observed by Zambon et al. can be attributed to their use of the Rlc1p-3GFP marker, which genetically interacts with myo2-E1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. FTD and ALS: genetic ties that bind.

    PubMed

    Orr, Harry T

    2011-10-20

    Curiously, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), seemingly disparate neurodegenerative disorders, can be inherited together. Two groups (DeJesus-Hernandez et al. and Renton et al.) show that the long sought after ALS/FTD mutation on chromosomal region 9p is a hexanucleotide expansion in C90RF72. These studies, plus a study on X-linked ALS/FTD, provide molecular starting points for identifying pathways that link ALS and FTD pathogenesis.

  10. Superconductivity in Al/Al2O3 interface

    NASA Astrophysics Data System (ADS)

    Palnichenko, A. V.; Vyaselev, O. M.; Mazilkin, A. A.; Khasanov, S. S.

    2016-06-01

    Metastable superconductivity at Tc ≈ 65 K has been observed in Al foil subjected to special oxidation process, according to the ac magnetic susceptibility and electrical resistance measurements. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed during the oxidation process between metallic aluminum and its oxide.

  11. Baumard et al.'s moral markets lack market dynamics.

    PubMed

    Fessler, Daniel M T; Holbrook, Colin

    2013-02-01

    Market models are indeed indispensable to understanding the evolution of cooperation and its emotional substrates. Unfortunately, Baumard et al. eschew market thinking in stressing the supposed invariance of moral/cooperative behavior across circumstances. To the contrary, humans display contingent morality/cooperation, and these shifts are best accounted for by market models of partner choice for mutually beneficial collaboration.

  12. `Operation and performance of a longitudinal feedback system using digital signal processing

    SciTech Connect

    Teytelman, D.; Fox, J.; Hindi, H.; Hoeflich, J.; Linscott, I.; Olsen, J.; Oxoby, G.; Sapozhnikov, L.; Drago, A.; Serio, M.; Barry, W.; Byrd, J.; Corlett, J.

    1995-05-05

    A programmable longitudinal feedback system using a parallel array of AT&T 1610 digital signal processors has been developed as a component of the PEP-II R&D program. This system has been installed at the Advanced Light Source (LBL) and implements full speed bunch by bunch signal processing for storage rings with bunch spacing of 4 ns. Open and closed loop results showing the action of the feedback system are presented, and the system is shown to damp coupled-bunch instabilities in the ALS. A unified PC-based software environment for the feedback system operation is also described. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  13. Design and Implementation of IIR Algorithms for Control of Longitudinal Coupled-Bunch Instabilities

    SciTech Connect

    Teytelman, Dmitry

    2000-05-16

    The recent installation of third-harmonic RF cavities at the Advanced Light Source has raised instability growth rates, and also caused tune shifts (coherent and incoherent) of more than an octave over the required range of beam currents and energies. The larger growth rates and tune shifts have rendered control by the original bandpass FIR feedback algorithms unreliable. In this paper the authors describe an implementation of an IIR feedback algorithm with more exible response tailoring. A cascade of up to 6 second-order IIR sections (12 poles and 12 zeros) was implemented in the DSPs of the longitudinal feedback system. Filter design has been formulated as an optimization problem and solved using constrained optimization methods. These IIR filters provided 2.4 times the control bandwidth as compared to the original FIR designs. Here the authors demonstrate the performance of the designed filters using transient diagnostic measurements from ALS and DAPNE.

  14. Relativistic electron beam driven longitudinal wake-wave breaking in a cold plasma

    SciTech Connect

    Bera, Ratan Kumar; Mukherjee, Arghya; Sengupta, Sudip; Das, Amita

    2016-08-15

    Space-time evolution of a relativistic electron beam driven wake-field in a cold, homogeneous plasma is studied using 1D-fluid simulation techniques. It is observed that the wake wave gradually evolves and eventually breaks, exhibiting sharp spikes in the density profile and sawtooth like features in the electric field profile [Bera et al., Phys. Plasmas 22, 073109 (2015)]. It is shown here that the excited wakefield is a longitudinal Akhiezer-Polovin mode [A. I. Akhiezer and R. V. Polovin, Sov. Phys. JETP 3, 696 (1956)] and its steepening (breaking) can be understood in terms of phase mixing of this mode, which arises because of relativistic mass variation effects. Further, the phase mixing time (breaking time) is studied as a function of beam density and beam velocity and is found to follow the well known scaling presented by Mukherjee and Sengupta [Phys. Plasmas 21, 112104 (2014)].

  15. Characterization of AlInGaN-based 405nm distributed feedback laser diodes

    NASA Astrophysics Data System (ADS)

    Masui, S.; Tsukayama, K.; Yanamoto, T.; Kozaki, T.; Nagahama, S.; Mukai, T.

    2008-02-01

    The first-order AlInGaN 405 nm distributed feed-back (DFB) laser diodes were grown on the low dislocation freestanding GaN substrates by a metal organic chemical vapor deposition method. The first-order diffractive grating whose period was 80 nm was formed into an n-type cladding layer. The fine tooth shape grating was obtained by the EB lithography and the dry etching. No additional threading dislocation could be found at the regrowth interface. As a result, we succeeded in demonstrating the first-order AlInGaN based 405 nm DFB laser diodes under cw operation. The threshold current and the slope efficiency were 22 mA and 1.44 W/A under continuous wave operation at 25 °C, respectively. The single longitudinal mode emission was maintained up to an output power of 60 mW. The fundamental transverse mode operation with a single longitudinal mode was observed in the temperature range from 15 °C to 85 °C at an output power of 30 mW. The lifetime was estimated to be 4000 h by the lifetime test which was carried out under the condition of a constant output power of 30mW at 25 °C for 1000 h. The single longitudinal mode emission was maintained for the life tested DFB laser diodes.

  16. Macrosegregation in Al-7Si alloy caused by abrupt cross-section change during directional solidification

    NASA Astrophysics Data System (ADS)

    Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2016-09-01

    Hypoeutectic Al-7 wt .% Si alloys were directionally solidified vertically downward in cylindrical molds that incorporated an abrupt cross-section decrease (9.5 mm to 3.2 mm diameter) which, after 5 cm, reverted back to 9.5 mm diameter in a Bridgman furnace; two constant growth speeds and thermal gradients were investigated. Thermosolutal convection and cross-section-change-induced shrinkage flow effects on macrosegregation were investigated. Dendrite clustering and extensive radial macrosegregation was seen, particularly in the larger cross-sections, before contraction and after expansion, this more evident at the lower growth speed. This alloy shows positive longitudinal macrosegregation near cross-section decrease followed by negative macrosegregation right after it; the extent of macrosegregation, however, decreases with increasing growth speed. Primary dendrite steepling intensified as solidification proceeded into the narrower section and negative longitudinal macrosegregation was seen on the re-entrant shelves at expansion. A two-dimensional model accounting for both shrinkage and thermo-solutal convection was used to simulate solidification and the resulting mushy-zone steepling and macrosegregation. The experimentally observed longitudinal and radial macrosegregation associated with the cross-section changes during directional solidification of an Al-7Si alloy is well captured by the numerical simulations.

  17. ALS - A unique design approach

    NASA Astrophysics Data System (ADS)

    Chamberlain, Roger A.

    1990-09-01

    An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

  18. Wadi Al Dawasir, Saudi Arabia

    NASA Image and Video Library

    2015-10-20

    In the middle of the Arabian desert the city Green Oasis Wadi Al Dawasir is being developed as a new urban center for the Wadi Al Dawasir region of Saudi Arabia, as shown in this image from NASA Terra spacecraft. Huge solar fields supply the entire city and the surrounding region with energy. Hundreds of circular agricultural fields are fed by center pivot irrigation apparatus, drawing water from subterranean aquifers. The image was acquired March 30, 2013, covers an area of 30 x 45 km, and is located at 20.2 degrees north, 44.8 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20077

  19. Characteristics of Friction Welding Between Solid Bar of 6061 Al Alloy and Pipe of Al-Si12CuNi Al Cast Alloy

    NASA Astrophysics Data System (ADS)

    Kimura, M.; Sakaguchi, H.; Kusaka, M.; Kaizu, K.; Takahashi, T.

    2015-11-01

    This paper describes the characteristics of friction welding between a solid bar of 6061 Al alloy and a pipe of Al-Si12CuNi (AC8A) Al cast alloy. When the joint was made by a continuous drive friction welding machine (conventional method), the AC8A portion of the joint showed heavy deformation and the AA6061 showed minimal deformation. In particular, the joint could not be successfully made with following conditions, because AC8A pipe side crushed due to insufficient friction heat or high pressure: a short friction time such as 0.3 s, high friction pressure such as 100 MPa, or high forge pressure such as 150 MPa. The heavy deformation of AC8A side was caused by increasing friction torque during braking. To prevent braking deformation until rotation stops, a joint was made by a continuous drive friction welding machine that has an electromagnetic clutch. When the clutch was released, the relative speed between both specimens simultaneously decreased to zero. When the joint was made with friction pressure of 25 MPa, friction time of 0.3 s, and forge pressure of 125 MPa, the joining could be successfully achieved and that had approximately 16% efficiency. In addition, when the joint was made with friction pressure of 25 MPa, friction time of 0.7 s, and forge pressure of 125 MPa, it had approximately 54% efficiency. However, all joints showed the fracture between the traveled weld interface and the AC8A side, because the weld interface traveled in the longitudinal direction of AC8A side from the first contacted position of both weld faying surfaces. Hence, it was clarified that the friction welding between a solid bar of AA6061 and a cast pipe of AC8A was not desirable since the traveling phenomena of the weld interface were caused by the combination of the shapes of the friction welding specimens.

  20. Commentary: Persistent Time Estimation Deficits in ADHD? From Developmental Trajectories to Individual Targets for Intervention--Reflections on Doehnert et al. (2013)

    ERIC Educational Resources Information Center

    Holtmann, Martin

    2013-01-01

    In this commentary, Martin Holtmann, discusses Doehnert and colleagues' article in this issue (Doehnert et al., 2013). Holtmann comments that the article illustrates the value of longitudinal electrophysiological and experimental approaches to disentangle different pathways underlying the phenotype of ADHD, and points out that their…