1,237 research outputs found
How Hertzian solitary waves interact with boundaries in a 1-D granular medium
We perform measurements, numerical simulations, and quantitative comparisons
with available theory on solitary wave propagation in a linear chain of beads
without static preconstrain. By designing a nonintrusive force sensor to
measure the impulse as it propagates along the chain, we study the solitary
wave reflection at a wall. We show that the main features of solitary wave
reflection depend on wall mechanical properties. Since previous studies on
solitary waves have been performed at walls without these considerations, our
experiment provides a more reliable tool to characterize solitary wave
propagation. We find, for the first time, precise quantitative agreements.Comment: Proof corrections, ReVTeX, 11 pages, 3 eps (Focus and related papers
on http://www.supmeca.fr/perso/jobs/
Quality of life of nursing home residents with dementia: Validation of the German version of the ICECAP-O
Objectives: To validate the ICECAP-O capability wellbeing measure's German translation in older people with dementia living in a nursing home, and to investigate the influence of proxy characteristics on responses. Method: Cross-sectional study. For 95 residents living in a German nursing home, questionnaires were completed by nursing professionals serving as proxy respondents. We investigated the convergent validity of the ICECAP-O with other Quality of Life (Qol) measures, the EQ-5D extended with a cognitive dimension (EQ-5D+C), the Alzheimer's Disease Related Quality of Life (ADRQL) measures, and the Barthel-index measure of Activities of Daily Living (ADL). Discriminant validity was investigated using bivaria
Experimental evidence of solitary wave interaction in Hertzian chains
We study experimentally the interaction between two solitary waves that
approach one to another in a linear chain of spheres interacting via the Hertz
potential. When these counter propagating waves collide, they cross each other
and a phase shift respect to the noninteracting waves is introduced, as a
result of the nonlinear interaction potential. This observation is well
reproduced by our numerical simulations and it is shown to be independent of
viscoelastic dissipation at the beads contact. In addition, when the collision
of equal amplitude and synchronized counter propagating waves takes place, we
observe that two secondary solitary waves emerge from the interacting region.
The amplitude of secondary solitary waves is proportional to the amplitude of
incident waves. However, secondary solitary waves are stronger when the
collision occurs at the middle contact in chains with even number of beads.
Although numerical simulations correctly predict the existence of these waves,
experiments show that their respective amplitude are significantly larger than
predicted. We attribute this discrepancy to the rolling friction at the beads
contacts during solitary wave propagation
Intrinsic Energy Localization through Discrete Gap Breathers in One-Dimensional Diatomic Granular Crystals
We present a systematic study of the existence and stability of discrete
breathers that are spatially localized in the bulk of a one-dimensional chain
of compressed elastic beads that interact via Hertzian contact. The chain is
diatomic, consisting of a periodic arrangement of heavy and light spherical
particles. We examine two families of discrete gap breathers: (1) an unstable
discrete gap breather that is centered on a heavy particle and characterized by
a symmetric spatial energy profile and (2) a potentially stable discrete gap
breather that is centered on a light particle and is characterized by an
asymmetric spatial energy profile. We investigate their existence, structure,
and stability throughout the band gap of the linear spectrum and classify them
into four regimes: a regime near the lower optical band edge of the linear
spectrum, a moderately discrete regime, a strongly discrete regime that lies
deep within the band gap of the linearized version of the system, and a regime
near the upper acoustic band edge. We contrast discrete breathers in anharmonic
FPU-type diatomic chains with those in diatomic granular crystals, which have a
tensionless interaction potential between adjacent particles, and highlight in
that the asymmetric nature of the latter interaction potential may lead to a
form of hybrid bulk-surface localized solutions
A practical guide for collecting farmers socio-economic and agronomic data: an AfSIS Project field protocol
One of the aims of the AfSIS (Africa Soil Information Service) project is to document farmers’ characteristics and practices to determine their ability to engage in effective soil and crop management. This document outlines how agronomic surveys are integrated with knowledge of farmers’ condition, wealth, status, access to knowledge, and access to markets, using pre-designed questionnaires and field surveys, and including the use of Global Positioning System-based field surveys and Geographic Information Systems
Economic evaluations of chronic obstructive pulmonary disease pharmacotherapy:how well are the real-world issues of medication adherence, comorbidities and adverse drug-reactions addressed?
INTRODUCTION: When estimating the cost-effectiveness or budget impact of chronic obstructive pulmonary disease (COPD) medication, it is common practice to use trial data for clinical inputs. However, such inputs do not always reflect the real-world situation. Previous reviews recognized the need for taking real-world data (medication adherence, comorbidity and adverse drug reactions [ADRs]) into account. Whether recent cost-effectiveness analyses of COPD medication implemented those recommendations is unknown. AREAS COVERED: The authors reviewed recent economic evaluations of COPD-maintenance treatments focusing on medication adherence, comorbidity and ADRs. EXPERT OPINION: In most registration trials of COPD treatment, strict inclusion and exclusion criteria are applied. During trials, patient monitoring is well controlled. As such, medication adherence is often higher than seen in less controlled, real-world environments with more heterogeneous characteristics. Additionally, safety data collected in trials may not be widely generalizable due to more comorbidity and polypharmacy in the real-world. Consequently, when merely relying on trial data, the impact of adherence, comorbidity and ADRs on the cost-effectiveness can be underestimated. To overcome these real-world data gaps, use of pragmatic trials and observational studies in addition to strictly controlled trial data is recommended. To catalyze implementation of these real-world issues, reporting checklists should be updated
Manejo de sistemas de produção de centeio visando a produção de forragem e de sementes para a agricultura familiar.
bitstream/item/78978/1/documento-319.pd
- …