5,050 research outputs found
Adaptive Communication as a Means toward better Performance
Executive Summary
The focus on the success factors for excellent performance has been growing in the last decades. One of the factors that is generally believed to have a positive relationship with organizational performance, is the internal communication process. Even though many practitioners and academics believe that there is a relationship between internal communication and organizational performance, there is little scientific evidence supporting this relationship. This study attempted to fill this gap in literature, by providing a definition on the concept of communication capability building and by empirically testing the existence of a relationship between communication capability building and organizational performance
Biological Markers and Alzheimer Disease: A Canadian Perspective
Decreased Ī²-amyloid1-42 and increased phospho-tau protein levels in the cerebrospinal fluid (CSF) are currently the most accurate chemical neurodiagnostics of sporadic Alzheimer disease (AD). A report (2007) of the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (2006) recommended that biological markers should not be currently requisitioned by primary care physicians in the routine investigation of subjects with memory complaints. Consideration for such testing should prompt patient referral to a specialist engaged in dementia evaluations or a Memory Clinic. The specialist should consider having CSF biomarkers (Ī²-amyloid1-42 and phospho-tau) measured at a reputable facility in restricted cases presenting with atypical features and diagnostic confusion, but not as a routine procedure in all individuals with typical sporadic AD phenotypes. We submit that developments in the field of AD biomarker discovery since publication of the 3rd CCCDTD consensus data do not warrant revision of the 2007 recommendations
Use of shallow samples to estimate the total carbon storage in pastoral soils
Using data from pastoral soils sampled by horizon at 56 locations across New Zealand, we conducted a meta-analysis. On average, the total depth sampled was 0.93 Ā± 0.026 m (Ā± SEM), and on a volumetric basis, the total C storage averaged 26.9 Ā± 1.8, 13.9 Ā± 0.6 and 9.2 Ā± 1.4 kg C mā»Ā² for allophanic (n=12), non-allophanic (n=40) and pumice soils (n=4), respectively. We estimated the total C storage, and quantified the uncertainty, using the data for samples taken from the uppermost A-horizon whose depth averaged 0.1 Ā± 0.003 m. For A-horizon samples of the allophanic soils, the mean C content was 108 Ā± 6 g C kgā»Ā¹ and the bulk density was 772 Ā± 29 kg mā»Ā³, for non-allophanic soils they were 51 Ā± 4 g C kgā»Ā¹ and 1055 Ā± 29 kg mā»Ā³, and for pumice soils they were 68 Ā± 9 g C kgā»Ā¹ and 715 Ā± 45 kg mā»Ā³. The C density āa product of the C content and bulk density āof the A-horizon samples was proportional to their air-dried water content, a proxy measure for the mineral surface area. By linear regression with C density of the A-horizon, the total C storage could be estimated with a standard error of 3.1 kg C mā»Ā², 19% of the overall mean
Adiabatic connection at negative coupling strengths
The adiabatic connection of density functional theory (DFT) for electronic
systems is generalized here to negative values of the coupling strength
(with {\em attractive} electrons). In the extreme limit
a simple physical solution is presented and its implications
for DFT (as well as its limitations) are discussed. For two-electron systems (a
case in which the present solution can be calculated exactly), we find that an
interpolation between the limit and the opposite limit of
infinitely strong repulsion () yields a rather accurate
estimate of the second-order correlation energy E\cor\glt[\rho] for several
different densities , without using virtual orbitals. The same procedure
is also applied to the Be isoelectronic series, analyzing the effects of
near-degeneracy.Comment: 9 pages, submitted to PR
Time without time: a stochastic clock model
We study a classical reparametrization-invariant system, in which ``time'' is
not a priori defined. It consists of a nonrelativistic particle moving in five
dimensions, two of which are compactified to form a torus. There, assuming a
suitable potential, the internal motion is ergodic or more strongly irregular.
We consider quasi-local observables which measure the system's ``change'' in a
coarse-grained way. Based on this, we construct a statistical timelike
parameter, particularly with the help of maximum entropy method and Fisher-Rao
information metric. The emergent reparametrization-invariant ``time'' does not
run smoothly but is simply related to the proper time on the average. For
sufficiently low energy, the external motion is then described by a unitary
quantum mechanical evolution in accordance with the Schr\"odinger equation.Comment: 18 pages; LaTeX. 4 (.ps) plus 2 (.gif) figure file
On the Friction of Carbon Black- and Silica-Reinforced BR and S-SBR Elastomers
Friction of carbon black- and silica-reinforced elastomers is studied experimentally and theoretically, using Perssonās model. The effect of reinforcement fillers on elasticity was determined by dynamical mechanical analysis. Carbon black-filled samples have a higher Youngās modulus than the silica-filled compounds. Silica-filled rubbers have a higher tan (Ī“) at lower temperatures and a lower loss tangent at higher temperatures, which is a rough indication for higher wet grip and lower rolling resistance, respectively. Friction tests on a ball-on-disk test rig were performed to study the effect of the reinforcement fillers and their amount on the friction between rubber samples (disks) and relatively smooth or rough granite surfaces (balls). The results were discussed and compared with the friction model presented by Persson. It was shown theoretically and experimentally that hysteresis does not play a significant role in the friction of rubber samples in contact with smooth granite and that it plays a minor role in contact with a rough granite sphere. Therefore, the hysteresis contribution of friction can be neglected in the contact of rubbers with just smooth spheres. Moreover, a higher friction coefficient is seen in samples with a higher content of fillers. Silica-filled compounds show a slightly higher coefficient of friction compared with the carbon black-filled compounds. The effect of attached wear debris to the granite surfaces on the friction level has been studied. The results are supported by SEM and confocal microscopic images of the wear debris itself and wear debris attached to the granite spheres, respectivel
Contact mechanics and friction for transversely isotropic viscoelastic materials
Transversely isotropic materials are an unique group of materials whose properties are the same along two of the principal axes of a Cartesian coordinate system. Various natural and artificial materials behave effectively as transversely isotropic elastic solids. Several materials can be classified as transversely isotropic materials including crystals, rocks, piezoelectrics, some biological tissues such as muscles, skin, cartilage tissue or brainstem and fibrous composites. In this study, the theory of contact mechanics developed by Persson is extended in such a way that it can model the contact and friction of a transversely isotropic viscoelastic solid in contact with a rigid rough surface. Numerical results show that anisotropy should be taken into account when dealing with transversely isotropic materials. The hysteresis friction between a transversely isotropic viscoelastic rubber, reinforced unidirectionally by fibers and two rough counter surfaces are measured by a pin-on-disk setup. The experimental results validate the theory
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