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Le terme de Gegenhalten a été créé par Karl Kleist pour définir une forme d'hypertonie qui reste souvent confondue avec le négativisme. Malheureusement, de nombreux référentiels de psychiatrie continuent à faire l'amalgame entre ces deux concepts. L'intérêt grandissant porté aux anomalies motrices dans les psychoses endogènes nous invite à retrouver cette finesse séméiologique, et cette revue est un premier pas dans ce sens. Le Gegenhalten classique est réactionnel : il n'y a pas d'augmentation de tonus au repos. Il oppose une résistance involontaire à la mobilisation passive dont l'apparition est parfois retardée. En l'absence de manœuvre de sensibilisation, il est possible que des formes mineures de Gegenhalten ne soit pas dépistées. Le Gegenhalten présente une résistance variable dans l'espace et dans le temps. Ainsi les articulations qui présentaient un Mitmachen , une réaction d'adaptation plastique aux changements de position, peuvent présenter un Gegenhalten l'instant d'après. En plus d'apparaître progressivement, il dépend, entre autres, de l'éveil émotionnel et de la position du corps et de la tête par rapport à la gravité. Le Gegenhalten peut s'accompagner d'un phénomène d'anticipation des mouvements passifs et avoir alors un aspect très irrégulier et erratique. Le Gegenhalten devrait être séparé du négativisme qui correspond à des comportements psychomoteurs plus élaborés. Enfin le Gegenhalten doit être distingué de la rigidité parkinsonienne, induite (ou révélée) par les antipsychotiques. L'absence de spécificité des échelles d'évaluation fait qu'un Gegenhalten soit pris pour un « parkinsonisme spontané », c'est-à-dire survenant chez des sujets psychotiques, naïfs de toute prise d'antipsychotiques. Better known in neurology by the expression paratonia coined by Ernest Dupré in 1907, the term Gegenhalten has remained dominant in psychiatry. While the term was created by Karl Kleist in 1927 to define a form of hypertonia in order to distinguish it from negativism, many current references continue to conflate the two concepts. Gegenhalten is the most frequent kind of hypertonia, and if its differential diagnosis with spasticity is generally easy, it is more difficult to distinguish it from parkinsonian rigidity, especially in psychiatric settings where antipsychotic-induced (or revealed) parkinsonism is frequent. Problematically, the most used evaluation scale for it, i.e., the Simpson-Angus scale does not allow for the distinction of Gegenhalten from parkinsonism. This could explain some of what is currently referred to as "spontaneous parkinsonism", i.e., a hypertonia reported to occur in psychotic patients who are not taking any antipsychotic medication. Classical Gegenhalten is reactive, i.e., it occurs in the absence of an increase in resting tonus. It opposes an involuntary resistance during passive mobilization, the appearance of which is often delayed, or may only be perceptible after frequent repetitions. Thus, in the absence of a sensitization maneuver, minor forms of Gegenhalten may go undetected. Gegenhalten opposes a variable resistance. For instance, it depends on position (enhanced by gravitation) or emotional arousal. It can also be masked by a Mitmachen , a form of automatic assistance which is also of locomotor origin (like the Gegenhalten). While the French school of psychiatry saw Gegenhalten as a lack of voluntary control of muscle relaxation, Karl Kleist viewed it as an exacerbation of postural fixation reactions. For him, Gegenhalten could also occur "spontaneously" under the simple effect of gravity. Kleist hypothesized that spontaneous Gegenhalten was a kind of hypersensitive postural fixation reaction that could account for catatonic rigidity. These hypotheses were hotly debated at the beginning of the 20th century and stimulated considerable research. The growing interest in motor abnormalities in endogenous psychoses invites us to reconsider them. Unfortunately, they cannot be understood without a return to a refined semiology which has since been forgotten. This review is a first step in this direction. [ABSTRACT FROM AUTHOR]

Copyright of Basic & Clinical Andrology is the property of BioMed Central and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The spring system is the key component of linear compressor, which is attractive in the field of household refrigeration due to its high efficiency and compact structure. Inspired by the traditional flexure spring, we proposed a novel cylindrical arm spiral spring for linear compressor with a comprehensive consideration on the cost, compactness and performance requirements. The design method of spring was introduced and different performance can be obtained by adjusting the internal radius, external radius, number of turns and wire diameter. The static displacement of spring was modelled by using FEA (Finite Element Analysis) method for various axial and radial force. And a specific fixture was built to measure the spring stiffness to verify the results obtained from FEA simulation. At last, the dynamic test of the linear compressor equipped with the proposed spring was conducted. The experimental results showed that the resonant frequency of linear compressor can meet the design requirements of 78 Hz without gas compressor, indicating that the application of this type of spring in the linear compressor is feasible. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to assess the arterial stiffness (AS) in black africans patients with systemic scleroderma. Patients and Methodology: A prospective cross-sectional hospital survey has been performed over a 6-month period, including 55 black african individuals, aged over 16 years and consenting, consisting of 29 patients with systemic scleroderma and 26 hospitalized controls. The finger-toe pulse wave velocity (ft-PWV) was recorded by popmetre® and comparaison between the 2 groups has been performed with statistical analysis. Results: The mean ft-PWV was 9,56 m/s ± 3,09 in the patient group and 7,71 m/s ± 2,63 in control group. The ft-PWV was significantly higher in patients with scleroderma compared to controls (p<0.0145). The study of the relationship between AS and independent variables in multivariate analysis demonstrated that having scleroderma increase by 1.81 times the value of the ft-PWV after adjustment for age and systolic blood pressure. Discussion: To our knowledge, this is the first assessment of the AS in black african patients with scleroderma. It shows that ft-PWV was significantly higher in patients with scleroderma compared to controls. Also, this high AS was imputable to the scleroderma. Conclusion: In Africa, the measurement of the AS by popmetre® could be a simple, rapid, non invasive and pratical early detection and follow-up of cardio-vascular involvments in the course of scleroderma. [ABSTRACT FROM AUTHOR]

Joints simulating typical connections of gypsum wallboard (GWB) sheathed walls were subjected to reversed cyclic loading. Three different empirical models were analyzed for the purpose of determining the most appropriate fastener slip equation. The power model was used to develop the fastener slip equations, for nails and screws, as a function of GWB density and fastener diameter. The accuracy of the developed fastener slip model is validated against full-scale shear wall tests. The predictive models seem to be able to replicate the wall behaviour with reasonable accuracy until ultimate capacity. The results show a reasonable agreement between the model prediction and those obtained from the shear wall tests. The model prediction for shear walls constructed with low fastener spacing is less accurate. This result was expected since the small fastener spacing violates the minimum spacing requirements in the design standard (CSA 2014) and caused a brittle failure. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La procédure de correction d’un modele analytique adopté pour une structure de construction est précédée d’une comparaison entre le set des données expérimentales et celui des données analytiques, pour une vérification préliminaire concernant la correspondance raisonnable entre ces données. Pour l’identification dynamique des parametres ont été élaborées diverses méthodes de correction des matrices de rigidité et de l’amortissement qui ont a leur base la méthode des moindres carrés dans le domaine des fréquences. L’algorithme proposé a comme résultat la correction de la matrice de rigidité d’un modele de calcul en utilisant comme données d’entrée seulement celles enregistrées pendant les essais expérimentaux.

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cracking properties of crumb rubber modified (CRM) asphalt binders containing wax additive were evaluated through the dynamic shear rheometer test at 25 °C and the bending beam rheometer test at −12 °C. The CRM binders were produced using three rubber contents of 5%, 10%, and 15% by the binder weight, and then mixed with two commercial wax additives of LEADCAP and Sasobit. Three states of original, short-term and long-term aging were applied to evaluate the cracking properties using rolling thin film oven and pressure aging vessel. From the results, it is concluded that (1) the increase of rubber content significantly decreases the binder stiffness at lower temperature, (2) the higher the rubber content, the lower the G*sin δ of CRM binders with wax additives at intermediate temperature, and (3) the rubber can be used to improve the cracking resistance of asphalt binders modified with wax. [ABSTRACT FROM AUTHOR]

Le syndrome malin des neuroleptiques est une complication du traitement par les neuroleptiques. Son incidence est estimée à 0,02% dans la population générale. Le traitement reste symptomatique et repose essentiellement sur l'arrêt immédiat du traitement antérieur. Nous rapportons l'observation clinique d'une patiente de 26 ans, schizophrénique sous Chlorpromazine, se présentant aux urgences pour la prise en charge d'un syndrome malin des neuroleptiques compliqué d'une hémorragie méningée et révélant une vascularite cérébrale.

Résumé Introduction Le syndrome de l’homme raide est une pathologie neurologique rare associant une rigidité fluctuante du tronc et des membres et des spasmes musculaires douloureux. Les variants cliniques incluent le syndrome des membres raides où la rigidité ne touche qu’un des membres et l’encéphalomyélite progressive avec rigidité et myoclonies ( progressive encephalomyelitis with rigidity and myoclonus [PERM]), caractérisée par l’association d’une raideur et de spasmes myocloniques avec des signes focaux. Observation Nous rapportons un cas de PERM, chez une patiente âgée de 73 ans, initialement explorée pour une altération de l’état général assortie de douleurs abdominales. Conclusion De par ses présentations cliniques diverses et parfois non neurologiques, le diagnostic de PERM est souvent fait tardivement. La recherche d’anticorps antineuropile dans le sérum et le LCR, et l’aspect de spasmes à l’électromyogramme sans atteinte myogène caractérisent cette pathologie neurologique atypique. Introduction Stiff-person syndrome is rare neurological disease, associating trunk rigidity and painful muscular spasms. A clinical variant of stiff person syndrome is the progressive encephalomyelitis with rigidity and myoclonus (PERM), which includes neurological cognitive disturbances. Case report We report a 73-year-old woman initially addressed for abdominal pain, anorexia and severe weight-loss, for whom diagnosis of PERM was made. Conclusion Because of its various clinical presentations, sometimes without evidence for neurological disease, the diagnosis of PERM is delayed. The presence of antineuropile antibodies associated with muscular spasms at electromyogram are strong evidence for this diagnosis. [ABSTRACT FROM AUTHOR]

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Copyright of Pan African Medical Journal is the property of Pan African Medical Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Individuals experiencing low back pain often present clinically with intervertebral joint dysfunction. The purpose of this study was to determine whether relative changes in stiffness at a single spinal joint alters neural responsiveness of lumbar muscle spindles to either vertebral movement or position. Methods: Muscle spindle discharge was recorded in response to 1mm L6 ramp and hold movements (0.5mm/s) in the same animal for lumbar laminectomy-only (n=23), laminectomy & L5/6 facet screw (n=19), laminectomy & L5/6 facetectomy (n=5) conditions. Mean instantaneous frequency (MIF) was calculated for the ramp-up, hold, ramp-down and post-ramp phases during each joint condition Results: Mean MIFs were not significantly different between the laminectomy-only and the other two types of joint dysfunction for the ramp-up, hold, ramp-down, or post-ramp phases. Conclusion: Stiffness changes caused by single facet joint dysfunction failed to alter spindle responses during slow 1mm ramp and hold movements of the L6 vertebra. [ABSTRACT FROM AUTHOR]

An experimental study investigated the California bearing ratio (CBR), shear strength, stiffness, and cyclic creep properties of crushed, reclaimed asphalt concrete pavement (RAP) - natural aggregate blends for granular base and subbase. The CBR was found to depend on the properties of the constituent materials and the compactive effort used to prepare the specimens. It was concluded that the CBR test may not be appropriate for evaluating the suitability of blended material for granular base construction. Based on the triaxial tests, it was observed that the addition of RAP to natural aggregate (Ontario Granular A) reduces the shear strength slightly and tends to increase the accumulated strain (deformation) that develops due to repetitive loading. The influence of RAP on the mechanical properties, including 'elastic' modulus, was sensitive to specimen preparation and preconditioning. For certain combinations of RAP and Granular A, the mechanical properties were similar to those of Granular A. The key to a stable blend was found to be compactive effort. [ABSTRACT FROM AUTHOR]

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Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper deals with cross-laminated composites consisting of unidirectional plies. These laminates were hygrothermally aging by variable environmental conditions. Indeed, the mechanical properties of laminates will be affected by the temperature and the humidity changes. When these cross laminates are subjected to quasi-static tensile stresses, the first type of damage that appears is the transverse cracking of the layers oriented at 90° reducing the laminates stiffness. In this paper, an analytical model based on the diffusion of shear was modified to evaluate the loss of rigidity caused by the laminates with hygrothermal aging the transient variation of the concentration depending on the density of cracks. The results clearly demonstrate the dependence of the degradation of elastic properties as a function of crack density and environmental conditions. [ABSTRACT FROM AUTHOR]

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Copyright of Annals of Forest Science (EDP Sciences) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper the behaviour of two “standard research sands”, widely used for experimental purposes, is compared in a torsional hollow cylinder apparatus under monotonic and cyclic loading conditions. Both sands are fine and uniform with D50 = 0.22 and 0.29 mm, respectively. However, their response to undrained monotonic loading at similar void ratios is dramatically different, with the finer sand showing strength reduction after peak and the coarser sand showing continuous increase in strength with torsional shear. The difference in response is mainly attributed to grain angularity and to a lesser degree to their grading. The results of drained torsional hollow cylinder tests show initial contraction followed by dilation. The stress ratio at phase transformation is uniquely defined by both drained and undrained tests for each sand. Cyclic loading instability is manifested by a sudden increase in shear strain and excess pore-water pressure leading to initial liquefaction. The instability initiates across the instability line for the sand showing strength reduction and across the phase transformation line for the sand showing continuous increase in strength with shearing. Both lines are defined under monotonic loading conditions. The liquefaction, stiffness, and damping characteristics of the sands are given in this paper. Dans cet article, le comportement de deux « sables de recherche standard »très utilisés à des fins expérimentales est comparé dans l’appareil de torsion sur cylindre creux sous des conditions de chargement monotonique et cyclique. Les deux sables sont fins et uniformes avec des D50 = 0.22 mm et 0.29 mm respectivement. Cependant, leurs réactions sous un chargement monotonique non drainé sont dramatiquement différentes, avec le sable plus fin montrant une réduction de résistance après le pic, et le sable plus gros montrant un accroissement continu de la résistance dans le cisaillement en torsion. La différence dans la réaction est attribuée principalement au caractère anguleux des grains et à un moindre degré à leur granulométrie. Les résultats des essais de torsion drainée sur cylindre creux montrent une contraction initiale suivie d’une dilatation. Le rapport de contraintes à la transformation des phases est uniquement défini tant par les essais drainés que non drainés pour chaque sable. Durant le chargement cyclique, une instabilité manifestée par un accroissement soudain de la déformation en cisaillement et de l’excédent de pression interstitielle menant à une liquéfaction initiale, se développe en travers de la ligne d’instabilité pour le sable montrant une réduction de résistance, et la ligne de transformation de phase pour le sable montrant un accroissement continu de résistance avec le cisaillement. Les deux lignes sont définies dans des conditions de chargement monotonique. Dans cet article, on donne les caractéristiques de liquéfaction, de rigidité et d’amortissement des sables. [ABSTRACT FROM AUTHOR]

The CSA A23.3 standard for reinforced concrete design provides both an implicit check of deflection control based on minimum member thickness requirements and a direct computation method for deflection. This paper reports on an analytical study that compared maximum span-to-depth ratios from the implicit deflection provisions against ratios determined from direct deflection calculations. Emphasis was placed on the deflection performance of lightly reinforced one-way slabs, including those with high-strength steel reinforcement. The results indicated that maximum span-to-depth ratios should decrease as the span length increases, as the design load increases or as the cracking moment decreases. In contrast to the current implicit provisions, the design strength of the longitudinal reinforcement did not have a significant effect on the minimum slab thickness required to satisfy common deflection criterion. Design aids were proposed, with implications for design presented through a case study of a multispan one-way slab system. Le code de pratique CSA A23.3 concernant le calcul des ouvrages en béton armé fournit une vérification implicite, basée sur le contrôle de la flexion, des exigences minimales de l’épaisseur des membrures et une méthode de calcul directe de la flexion. Le présent article aborde une étude analytique qui comparait les rapports maximaux de travée-profondeur provenant des provisions implicites de la déflexion contre les rapports déterminés par le calcul direct de la flexion. Le rendement en flexion des dalles unidirectionnelles légèrement armées, incluant celles comportant une armature en acier à haute résistance, a été principalement examiné. Les résultats indiquent que les rapports maximaux de travée-profondeur devraient diminuer lorsque la longueur de la travée augmente, la charge de calcul augmente ou lorsque le moment de fissuration diminue. Par rapport aux provisions implicites actuelles, la résistance de calcul des renforcements longitudinaux n’a pas d’effet important sur l’épaisseur minimale de dalle requise pour répondre adéquatement au critère de flexion commun. Des aides à la conception ont été proposées et des conséquences pour la conception sont présentées dans une étude de cas d’un système à travées multiples de dalles unidirectionnelles. [ABSTRACT FROM AUTHOR]

The CSA A23.3 standard permits the use of a moment-magnifier approach for the design of slender reinforced concrete and composite steel-concrete columns. This approach is strongly influenced by the effective flexural stiffness (EI), which varies due to the nonlinearity of the concrete stress-strain curve and the cracking along the column length, among other factors. The EI equations given in the CSA standard are approximate when compared with the EI values computed from the axial load - bending moment - curvature relationships. This study was conducted to determine the influence of a full range of variables on EI used for the design of slender reinforced concrete and composite steel-concrete columns, and also to examine the existing CSA EI equations. Over 27 000 isolated concrete columns, each with a different combination of specified variables, in symmetrical single-curvature bending were simulated to generate the stiffness data. Two new design equations to compute EI of structural concrete columns were then developed from the simulated stiffness data and are proposed as an alternative to the existing CSA design equations for EI. [ABSTRACT FROM AUTHOR]

Résumé: On détermine les classes d''isomorphisme des algèbres de Jordan en dimension deux sur le corps des nombres réels. En utilisant des techniques d''Analyse Non Standard, on étudie les propriétés de la variété des lois d''algèbres de Jordan, et aussi les contractions parmi ces algèbres. [Copyright &y& Elsevier]

Summary: Introduction: Neurophysiological assessment can provide quantitative measures for the selected motor signs that have been targeted for surgery and may be helpful in predicting the therapeutic effects of deep brain stimulation (DBS) on pathological tremor, motor performance, and rigidity. Objective: To present a survey and demonstrate the contribution of neurophysiological assessment of side effects and effects on disabling motor symptoms at various steps of DBS surgery, and to confirm its role for optimal target localization, as an adjuvant to anatomic imaging. Material and methods: The data result from 192 nuclei in 118 procedures on patients with Parkinson''s disease (84), essential tremor (24), Hallenvorder Spatz dystonia (4), multiple sclerosis (4), and Holmes tremor (2). The intraoperative neurophysiological monitoring (IOM) protocol consists of semimicroelectrode recording (for subthalamic nuclei), whereas accelerotransducers and spectral analysis allow assessment of tremor, finger tapping (FT), diadochokinesis (DDK), and determination of the distance between DBS electrodes and internal capsule (IC). Rigidity is assessed by surface EMG recordings in combination with a goniometer. Results: The determination of the functional distance between the DBS electrode and the IC is based on the activation functions of axons in the IC. We show the high sensitivity of accelerometers for tremor over a large part of the body, the relationship between clinical scores and spectral frequencies of FT and DDK. Parkinsonian rigidity can be assessed from surface EMG (sEMG) by means of a balance coefficient, which can detect negative rigidity, for low unified Parkinson''s disease rating scale (UPDRS) scores (0–2) and quantified EMG when negative rigidity is excluded. Conclusion: Accelerometer and sEMG recording have shown their value for intraoperative assessment of disabling motor symptoms and side effects during surgery, to optimize the target position electrodes for DBS. The combination with contemporary signal analyzing techniques permit intraoperative monitoring without a significant delay. IONM improves sensitivity and adds objective neurophysiological data. [Copyright &y& Elsevier]

Copyright of Acta Mathematica (Springer Nature) is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Masonry component products are increasingly made industrially with reduced variation in mechanical properties. The joint is the only part of the masonry that is affected by manual action and so the load bearing capacity is not only determined by the quality of the bricks and mortar used but moreover by the way the masonry has been built and cured. As a result, it may be expected that the largest material variations are at the brick–mortar interfaces. This has been observed as irregular interface bonding with a bonded central area surrounded by fissures. As a consequence of the final shape of the joint, forces concentrate in the central part of the joint and strain variations occur near fissure tips which result in spalling of bricks in experiments. This paper demonstrates the need for detailed deformational measurements in the brick–mortar interface region. To overcome the limitations with traditional measuring instruments, a refined methodology based on the laser speckle technique is introduced in a companion paper [Canadian Journal of Civil Engineering, 34(11), 1467 (2007)] by the authors of this paper. [ABSTRACT FROM AUTHOR]

Airway hyperresponsiveness is the excessive narrowing of the airway lumen caused by stimuli that would cause little or no narrowing in the normal individual. It is one of the cardinal features of asthma, but its mechanisms remain unexplained. In asthma, the key end-effector of acute airway narrowing is contraction of the airway smooth muscle cell that is driven by myosin motors exerting their mechanical effects within an integrated cytoskeletal scaffolding. In just the past few years, however, our understanding of the rules that govern muscle biophysics has dramatically changed, as has their classical relationship to airway mechanics. It has become well established, for example, that muscle length is equilibrated dynamically rather than statically, and that in a dynamic setting nonclassical features of muscle biophysics come to the forefront, including unanticipated interactions between the muscle and its time-varying load, as well as the ability of the muscle cell to adapt (remodel) its internal microstructure rapidly in response to its ever-changing mechanical environment. Here, we consider some of these emerging concepts and, in particular, focus on structural remodeling of the airway smooth muscle cell as it relates to excessive airway narrowing in asthma. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents partial results of a research program under way at Laval University for which the main goal is to introduce the behaviour of steel connections into commercial structural analysis software. The objective of this paper is to derive analytical characterization equations for three commonly used steel column base connections. The procedure to derive these equations is based on a curve standardization theory that requires a number of experimental results in the form of moment–rotation curves that characterize the behaviour of column base connections. Because of a lack of available experimental results, data were obtained from finite element models. The design of a simple steel structure introducing the semi-rigid behaviour of column bases is presented as an example. It shows that consideration of the semi-rigidity of column base connections increases the accuracy of the analysis results and leads to a decrease in structure weight and deformation. [ABSTRACT FROM AUTHOR]

This paper describes the behaviour of axially loaded short and long square hollow structural section (HSS) columns, strengthened with carbon fibre reinforced polymer (CFRP) sheets. Twenty-seven short-column and five long-column HSS specimens were tested. The effect of CFRP sheet orientation in the longitudinal and transverse directions was studied for short columns. For long columns, CFRP sheets were oriented in the longitudinal direction only. A maximum strength gain of 18% was achieved for short columns with two transverse CFRP layers. For long columns, the maximum strength gain of 23% was achieved with three longitudinal CFRP layers applied on four sides. In all CFRP-strengthened long columns, lateral deflections were reduced. Strength gain in long columns was highly dependent on the column's imperfection. As such, no correlation was established between strength gain and number of CFRP layers. CAN/CSA 16-01 equation was modified to account for CFRP through transformed section analysis so that they could be used to predict the axial-load capacity of long columns. [ABSTRACT FROM AUTHOR]

A generalized numerical method is proposed to derive the static and dynamic stiffness matrices and to handle the nodal load vector for static analysis of non-uniform Timoshenko beam–columns under several effects. This method presents a unified approach based on effective utilization of the Mohr method and focuses on the following arbitrarily variable characteristics: geometrical properties, bending and shear deformations, transverse and rotatory inertia of mass, distributed and (or) concentrated axial and (or) transverse loads, and Winkler foundation modulus and shear foundation modulus. A successive iterative algorithm is developed to comprise all these characteristics systematically. The algorithm enables a non-uniform Timoshenko beam–column to be regarded as a substructure. This provides an important advantage to incorporate all the variable characteristics based on the substructure. The buckling load and fundamental natural frequency of a substructure subjected to the cited effects are also assessed. Numerical examples confirm the efficiency of the numerical method. [ABSTRACT FROM AUTHOR]

The helical pile is a foundation system that is used to support new residential and commercial buildings and to stabilize repairs of existing structures. It represents an attractive option to upgrade the seismic resistance of foundations. This necessitates a good understanding of the seismic performance of the specialized connectors linking the pile shaft to the concrete foundation. An experimental program is initiated at The University of Western Ontario to investigate the seismic performance of these connectors, to develop models that can be used in finite element analysis to describe their behaviour, and to propose modifications to enhance their seismic performance, if necessary. In this program, eight specimens were tested to assess the behaviour of two types of these connectors under different loading modes. It was concluded that connectors with an uplift bracket are required for seismic applications to control uplift displacement due to rocking of the foundation. [ABSTRACT FROM AUTHOR]

The expansion attained by a concrete affected by alkali-silica reaction (ASR) is an important parameter in the evaluation of the corresponding structure. In part I, relationships were established in the laboratory between the ASR expansion and the stiffness damage test (SDT), the damage rating index (DRI), and the cumulated width of cracks observed at the surface of concrete specimens made with various types of reactive aggregates. In part II, these relationships were verified in the case of specimens made in laboratory but exposed outdoors. In part III, the aforementioned methods were applied to three ASR-affected structures. The measurement of crack widths at the surface of the affected members allowed a rather good estimation of the concrete expansion, provided the measurements were taken on the most severely exposed sections of these members. The DRI did not allow differentiating the most visually and mechanically affected concretes from the least affected concretes. The SDT proved to be the most interesting method to date for evaluating the expansion of ASR-affected concrete; however, it seemed to underestimate the expansion of the prestressed concrete members investigated. [ABSTRACT FROM AUTHOR]

Abstract: We call a finite-dimensional complex Lie algebra strongly rigid if its universal enveloping algebra is rigid as an associative algebra, i.e., every formal associative deformation is equivalent to the trivial deformation. In quantum group theory this phenomenon is well known to be the case for all complex semisimple Lie algebras. We show that a strongly rigid Lie algebra, over a field of characteristic 0, has to be rigid as Lie algebra, and that in addition its second scalar cohomology group has to vanish (which excludes nilpotent Lie algebras of dimension greater or equal than two). Moreover, using Kontsevitch''s theory of deformation quantization we show that every polynomial deformation of the linear Poisson structure on which induces a nonzero cohomology class of a complex Lie algebra leads to a nontrivial deformation of . Hence every Poisson structure on a vector space which is zero at some point and whose linear part is a strongly rigid Lie algebra is therefore formally linearizable in the sense of A. Weinstein. Finally we provide examples of rigid Lie algebras which are not strongly rigid, and give a classification of all strongly rigid Lie algebras up to dimension 6. [Copyright &y& Elsevier]

A trilinear bending moment – curvature model is used to develop a general method for determining the effective flexural stiffness of concrete walls for use in linear seismic analysis. The method accounts for the initial section stiffness EcIg prior to cracking and the retention of initial stiffness after cracking due to axial compression from gravity loads closing cracks. Accounting for the initial stiffness is particularly important for typical high-rise concrete walls, which have significant compression and low percentages of vertical reinforcement. The effective flexural stiffness is determined from the slope of the elastic portion of an equivalent elastic-plastic load–deflection curve that has the same area under the curve as the actual nonlinear relationship. The general method requires information about the vertical reinforcement and strength of the wall. Simplified expressions are proposed to estimate the effective flexural stiffness based only on the axial compression near the base of the wall. Separate expressions for upper- and lower-bound effective stiffness establish the range of possible values, and this is less than the variation of recommendations in the literature on how much to reduce the flexural stiffness of concrete walls to account for cracking. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is postulated that for purposes of seismic design, the ductile behaviour of lateral force-resisting wall components, elements, and indeed the entire system can be satisfactorily simulated by bilinear force–displacement modeling. This enables displacement relationships between the system and its constituent components at a particular limit state to be readily established. To this end, some widely used fallacies, relevant to the transition from the elastic to the plastic domain of behaviour, are exposed. A redefinition of stiffness and yield displacement allows more realistic predictions of the important feature of seismic response, component displacements, to be made. The concepts are rational, yet very simple. Their applications are interwoven with the designer's intentions. Contrary to current design practice, whereby a specific global displacement ductility capacity is prescribed for a particular structural class, the designer can determine the acceptable displacement demand to be imposed on the system. This should protect critical components against excessive displacements. Specific intended displacement demands and capacities of systems comprising reinforced concrete cantilever and coupled walls can be estimated.Key words: ductility, displacements, reinforced concrete, seismic design, stiffness, structural walls.Il est postulé que, pour la conception parasismique, le comportement ductile des composantes résistant aux forces latérales, les éléments et le système tout entier d'ailleurs, peut être simulé de façon satisfaisante par un modèle bi-linéraire force–déplacement. Ceci permet d'établir des relations entre le déplacement du système et ces composantes à un état limite particulier facilement établi. Cependant, plusieurs erreurs sont exposées au sujet de la transition entre le comportement du domaine élastique au domaine plastique. Une redéfinition de la rigidité et du déplacement permet des prédictions plus réalistes des traits importants de la réponse sismique, déplacement des composantes, à être fait. Les concepts sont logiques et très simples. Leurs applications sont entremêlées avec les intentions du concepteur. Contrairement aux pratiques de conception courantes, par lesquelles une capacité spécifique de déplacement ductile global est prescrite pour une classe structurale particulière, le concepteur peut déterminer le niveau de déplacement acceptable a être imposé au système. Ceci devrait protéger les composantes critiques contre des déplacements excessifs. Les demandes et les capacités de déplacements spécifiques voulus des systèmes comprenant des murs à porte-à-faux et couplés en béton armé peuvent être estimés.Mots clés : ductilité, déplacements, béton armé, conception parasismique, rigidité, murs structuraux.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

An experimental program consisting of 36 reinforced concrete masonry wall specimens comprised of 400 × 200 × 150 mm standard units in two series of tests was carried out to investigate the behaviour of masonry walls under combined axial and lateral loading. W2R series specimens had a single layer of vertical steel, and W4R series specimens had a double layer of vertical steel. Test results show that the effective wall stiffness, (EI)[sub eff] , differs from currently specified code values in regions where compression failure tends to predominate. Overall test results presented graphically in the form of lateral load versus deflection, axial load versus moment, and (EI)[sub eff] versus eccentricity ratio, e/t, indicate that the current Canadian masonry design code underestimates the effective stiffness of walls with eccentricity ratios e/t < 0.4.Key words: beam–column, masonry, reinforcement, experimental, rigidity, moment magnifier.Un programme expérimental, impliquant trente-six spécimens de parois de maçonnerie composés d'unités standards de 400 × 200 × 150 mm pour deux séries de tests, a été entrepris afin d'examiner le comportement de parois de maçonnerie sous des charges axiales et latérales combinées. La série de spécimens identifiée par le terme W2R n'a qu'une simple couche d'acier vertical, alors que la série de spécimens identifiée par le terme W4R possède deux couches d'acier vertical. Les résultats montrent que la rigidité efficace de la paroi, (EI)[sub eff] , diffère des valeurs présentement spécifiées dans le code dans les régions où la défaillance à la compression semble être prédominante. Les résultats globaux des tests, présentés graphiquement sous les formes charge latérale versus déflexion, charge axiale versus moment, et (EI)[sub eff] versus rapport d'excentricité e/t, indiquent que le présent code canadien de conception de maçonnerie sous-estime la rigidité efficace de parois avec des rapports d'excentricité e/t < 0,4.Mots clés : poutre–colonne, maçonnerie, renforcement, expérimental, rigidité, amplificateur de moment.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Quantitative application of elastoplastic theory to the yielding behaviour of natural soils has always been uncertain. Part of the reason is that the theory was developed for reconstituted materials with isotropic structure, in contrast to natural soils that are usually anisotropic. The approach considered in this study assumes that pre-yielding behaviour is governed by the theory of linear anisotropic elasticity and that yield loci in the mean effective stress ( p') – deviator stress (q) plane are aligned approximately along the coefficient of earth pressure (K[sub 0] ) line. The assumption of a rotated yield locus associated with anisotropic elastic behaviour within the state boundary surface indicates that the elastic wall within the state boundary surface is inclined. The form of the state boundary surface has been determined mathematically in terms of anisotropic elastic and Cam-Clay soil parameters. Stress path tests were conducted on samples of Belfast Upper Boulder Clay removed from a depth of 28 m below ground surface. Good agreement was found between predicted and measured yield loci. The study also examined the influence of subsequent isotropic compression on the yielding characteristics of the natural clay. The indications are that the anisotropy developed during deposition disappears when the sample is loaded to a stress level at least twice the stress generated during the original deposition process. The methods developed in the paper have also been applied to test results reported previously on Winnipeg clay, and good agreement was obtained.Key words: sampling, anisotropy, elasticity, suction, stiffness, yielding.L'application quantitative de la théorie élasto-plastique au comportement à la limite d'élasticité des sols naturels a toujours été incertaine. Ceci est dû en partie au fait que la théorie a été développée pour des matériaux reconstitués avec une structure isotrope, alors qu'au contraire, les sols naturels sont habituellement anisotropes. L'approche considérée dans cette étude suppose que le comportement en deçà de la limite élastique est réglementé par la théorie d'élasticité linéaire anisotrope et que les points de déformation plastique dans le plan p': q sont alignés approximativement le long de la ligne K[sub 0] . L'hypothèse d'une ligne de limite élastique circulaire reliée au comportement élastique anisotrope à l'intérieur de la surface d'état limite indique que la surface élastique à l'intérieur de la surface d'état limite est inclinée. La forme de la surface d'état limite a été déterminée mathématiquement en fonction des paramètres d'élasticité anisotrope et de Cam-Clay des sols. Des essais de cheminement de contraintes ont été réalisés sur des échantillons du Belfast Upper Boulder Clay prélevés à une profondeur de 28 m sous la surface du terrain. L'on a trouvé une bonne concordance entre les limites élastiques prédites et mesurées. L'étude examine aussi l'influence de la compression isotrope subséquente sur les caractéristiques de déformation de l'argile naturelle. Les indications sont à l'effet que l'anisotropie développée au cours de la déposition disparaît lorsque l'échantillon est chargé à un niveau de contrainte égal à au moins deux fois la contrainte générée durant le processus de déposition originale. Les méthodes développées dans l'article ont également été appliquées aux résultats d'essais sur l'argile de Winnipeg déjà publiés. Une bonne concordance a aussi été obtenue.Mots clés : échantillonnage, anisotropie, élasticité, succion, rigidité, limite élastique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Natural cementation affects the properties of soils, the interpretation of in situ and laboratory test results, and the selection of criteria for geotechnical design. In this paper, published experimental studies are reviewed, a microscale analysis is presented of the effect of cementation on small-strain stiffness for distinct stress-cementation histories, and the effect of cementation on small-strain velocity and damping is experimentally studied. Observations include the prevailing effects of cementation over effective stress, the coexistence of frictional and viscous losses, and the effects of decementation when the medium is unloaded from the level of confinement prevailing during cementation.Key words: wave velocity, seismic response, stiffness, damping, sampling effects, loading history.La cimentation naturelle affecte les propriétés des sols, l'interprétation des résultats des essais in situ et en laboratoire, et la sélection de critères pour la conception géotechnique. Dans cet article, des études expérimentales publiées sont passées en revue, suivies par une analyse de l'effet de la cimentation sur la rigidité à faible déformation pour les histoires distinctes de cimentation de contraintes. Ensuite, on étudie expérimentalement l'effet de la cimentation sur la vitesse à faible contrainte et sur l'amortissement. Les observations comprennent les effets de la cimentation prévalant sur la contrainte effective, la coexistence des pertes visqueuse en frottement, et les effets de la cimentation lorsque le milieu est déchargé par rapport au niveau de confinement prévalant durant la cimentation.Mots clés : vitesse d'ondes, réponse sismique, rigidité, amortissement, effets de l'échantillonnage, histoire des contraintes.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Copyright of European Spine Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)