989 research outputs found

    Improved cavity-type absolute total-radiation radiometer

    Get PDF
    Conical cavity-type absolute radiometer measures the intensity of radiant energy to an accuracy of one to two percent in a vacuum of ten to the minus fifth torr or lower. There is a uniform response over the ultraviolet, visible, and infrared range, and it requires no calibration or comparison with a radiation standard

    Conically shaped cavity radiometer with a dual purpose cone winding Patent

    Get PDF
    Black body radiometer design with temperature sensing and cavity heat source cone windin

    A Production System Model of Capturing Reactive Moving Targets

    Get PDF
    Subjects manipulated a control stick to position a cursor over a moving target that reacted with a computer-generated escape strategy. The cursor movements were described at two levels of abstraction. At the upper level, a production system described transitions among four modes of activity; rapid acquisition, close following, a predictive mode, and herding. Within each mode, differential equations described trajectory-generating mechanisms. A simulation of this two-level model captures the targets in a manner resembling the episodic time histories of human subjects

    Intergenerational Pathways From Reflective Functioning to Infant Attachment Through Parenting

    Get PDF
    The aim of this prospective study was to examine temporal pathways from mothers’ reflective functioning (RF) through parenting to infant attachment measured more than 16 months later. Participants were 88 mother–infant dyads from demographically diverse backgrounds and included a group of mothers with histories of childhood maltreatment. RF was assessed using the RF rating of the Adult Attachment Interview before the birth of the baby. Parenting was assessed when the infants were 6 months old using the Maternal Sensitivity scale, as well as when they were 16 months using the Disconnected and Extremely Insensitive Parenting scale. Infant attachment was assessed when the infants were 16 months old using the Strange Situation. As hypothesised, the study findings showed that mothers’ mentalization regarding their own early attachment relationships was associated with later parenting and infant attachment. Negative parenting behaviours explained the link between mothers’ RF about their own attachment relationships and infant attachment disorganization. The findings suggest that mothers’ mentalization about their early attachment relationships has important implications in the transition to becoming parents themselves. Mentalization appears to be particularly important in helping mothers screen and inhibit negative parenting behaviours that would otherwise undermine infant attachment security and organization

    A mediation meta-analysis of the role of maternal responsivity in the association between socioeconomic risk and children's language

    Get PDF
    This meta-analysis tested maternal responsivity as a mediator of the association between socioeconomic risk and children's preschool language abilities. The search included studies up to 2017 and meta-analytic structural equation modeling, allowed us to examine the magnitude of the indirect effect across 17 studies (k = 19). The meta-analysis included 6433 predominantly White, English speaking children (Mage  = 36 months; 50% female) from Western, industrialized countries. All paths in the model were statistically significant, notably, the indirect effect was significant (b = -.052), showing that maternal responsivity may be a proximal intervening variable between socioeconomic risk and children's language development. Moderator analyses found that the indirect effect was stronger for sensitive parenting than warmth and when parenting was assessed in the family home

    iDeLog: Iterative Dual Spatial and Kinematic Extraction of Sigma-Lognormal Parameters

    Full text link
    The Kinematic Theory of rapid movements and its associated Sigma-Lognormal model have been extensively used in a large variety of applications. While the physical and biological meaning of the model have been widely tested and validated for rapid movements, some shortcomings have been detected when it is used with continuous long and complex movements. To alleviate such drawbacks, and inspired by the motor equivalence theory and a conceivable visual feedback, this paper proposes a novel framework to extract the Sigma-Lognormal parameters, namely iDeLog. Specifically, iDeLog consists of two steps. The first one, influenced by the motor equivalence model, separately derives an initial action plan defined by a set of virtual points and angles from the trajectory and a sequence of lognormals from the velocity. In the second step, based on a hypothetical visual feedback compatible with an open-loop motor control, the virtual target points of the action plan are iteratively moved to improve the matching between the observed and reconstructed trajectory and velocity. During experiments conducted with handwritten signatures, iDeLog obtained promising results as compared to the previous development of the Sigma-Lognormal.Comment: Accepted Version published by Transactions on Pattern Analysis and Machine Intelligenc

    Effects of sex, age, body height and body weight on spinal loads: sensitivity analyses in a subject-specific trunk musculoskeletal model.

    Get PDF
    Subject-specific parameters influence spinal loads and the risk of back disorders but their relative effects are not well understood. The objective of this study is to investigate the effects of changes in age (35-60 years), sex (male, female), body height (BH: 150-190 cm) and body weight (BW: 50-120 kg) on spinal loads in a full factorial simulation using a personalized (spine kinematics, geometry, musculature and passive properties) kinematics driven musculoskeletal trunk finite element model. Segmental weight distribution (magnitude and location along the trunk) was estimated by a novel technique to accurately represent obesity. Five symmetric sagittal loading conditions were considered, and main effect plots and analyses of variance were employed to identify influential parameters. In all 5 tasks simulated, BW (98.9% in compression and 96.1% in shear) had the greatest effect on spinal loads at the L4-L5 and L5-S1 levels followed by sex (0.7% in compression and 2.1% in shear), BH (0.4% in compression and 1.5% in shear) and finally age (<5.4%). At identical BH and BW, spinal loads in females were slightly greater than those in males by ~4.7% in compression and ~8.7% in shear. In tasks with no loads in hands, BW-normalized spinal loads further increased with BW highlighting the exponential increase in spinal loads with BW that indicates the greater risk of back disorders especially in obese individuals. Uneven distribution of weight in obese subjects, with more BW placed at the lower trunk, further (though slightly <7.5%) increased spinal loads.This work was supported by the institut de recherche Robert-Sauvé en santé et en sécurité du travail 294 (IRSST-2014-0009) and the fonds de recherche du Québec en nature et technologies (FRQNT)

    Sigma-lognormal modeling of speech

    Full text link
    Human movement studies and analyses have been fundamental in many scientific domains, ranging from neuroscience to education, pattern recognition to robotics, health care to sports, and beyond. Previous speech motor models were proposed to understand how speech movement is produced and how the resulting speech varies when some parameters are changed. However, the inverse approach, in which the muscular response parameters and the subject's age are derived from real continuous speech, is not possible with such models. Instead, in the handwriting field, the kinematic theory of rapid human movements and its associated Sigma-lognormal model have been applied successfully to obtain the muscular response parameters. This work presents a speech kinematics based model that can be used to study, analyze, and reconstruct complex speech kinematics in a simplified manner. A method based on the kinematic theory of rapid human movements and its associated Sigma lognormal model are applied to describe and to parameterize the asymptotic impulse response of the neuromuscular networks involved in speech as a response to a neuromotor command. The method used to carry out transformations from formants to a movement observation is also presented. Experiments carried out with the (English) VTR TIMIT database and the (German) Saarbrucken Voice Database, including people of different ages, with and without laryngeal pathologies, corroborate the link between the extracted parameters and aging, on the one hand, and the proportion between the first and second formants required in applying the kinematic theory of rapid human movements, on the other. The results should drive innovative developments in the modeling and understanding of speech kinematics.Comment: Published in Open Acce
    corecore