111 research outputs found
A numerical study of turbulence influence on saltating grains
River hydrodynamicsTurbulent open channel flow and transport phenomen
Leczenie żywieniowe w neurologii — stanowisko interdyscyplinarnej grupy ekspertów. Część II. Rola żywienia w chorobie Parkinsona
Choroba Parkinsona (PD, Parkinson’s disease) to schorzenie neurozwyrodnieniowe z osiowymi objawami, takimi jak bradykinezja, sztywność, drżenie i zaburzenia odruchów postawnych. Prawidłowe odżywianie oraz dostosowanie diety do przyjmowanych leków ma istotne znaczenie na każdym etapie choroby. U niektórych pacjentów w zaawansowanym stadium PD obserwuje się chudnięcie (niekorzystny wskaźnik przebiegu choroby). Terapie w zaawansowanym okresie także wpływają na zmianę masy ciała — dochodzi do jej zwiększenia po zabiegach głębokiej stymulacji mózgu czy chudnięcia po założeniu systemu Duodopa. Metabolizm lewodopy sprzyja powstawaniu homocysteiny, co prawdopodobnie może mieć związek z powstawaniem obwodowych neuropatii, nasileniem osteoporozy (ryzyko złamań) oraz pogorszeniem funkcji poznawczych i wymaga suplementowania kwasu foliowego oraz witaminy B12 w celu ich uniknięcia. Dieta zaburza również wchłanianie lewodopy i wymaga odpowiedniego dostosowania, aby utrzymać skuteczność terapii. Od wczesnych stadiów choroby dokuczliwe są zaparcia (modyfikacja diety) oraz dysfagia z ryzykiem poważnych powikłań (zachłyśnięcie) lub po prostu nieprzewidywalnym działaniem leków doustnych. Hipotonia ortostatyczna wymaga odpowiedniej podaży płynów i unikania obfitych posiłków. Wszystkie te problemy mogą znacznie pogarszać jakość życia chorego i wymagają skutecznych interwencji w celu zapobiegania powikłaniom. Rekomendacje grupy ekspertów w zakresie odżywiania mają pomóc w codziennej opiece nad chorymi z PD
Toward modeling turbulent suspension of sand in the nearshore
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C06018, doi:10.1029/2003JC002240.We present two depth- and phase-resolving models, based on single- and two-phase approaches for suspended sediment transport under water waves. Both models are the extension of a wave hydrodynamic model Cornell Breaking Wave and Structure (COBRAS). In the two-phase approach, dilute two-phase mass and momentum equations are calculated along with a fluid turbulence closure based on balance equations for the fluid turbulence kinetic energy k f and its dissipation rate ε f . In the single-phase approach the fluid flow is described by the Reynolds-Averaged Navier-Stokes equations, while the sediment concentration is calculated by an advection-diffusion equation for the conservation of sediment mass. The fluid turbulence is calculated by k f -ε f equations that incorporate the essential influence of sediment, which can also be consistently deduced from the two-phase theory. By adopting a commonly used sediment flux boundary condition near the bed the proposed models are tested against laboratory measurements of suspended sediment under nonbreaking skewed water waves and shoaling broken waves. Although the models predict wave-averaged sediment concentrations reasonably well, the corresponding time histories of instantaneous sediment concentration are less accurate. We demonstrate that this is due to the uncertainties in the near-bed sediment boundary conditions. In addition, we show that under breaking waves the near-bed sediment pickup cannot be solely parameterized by the bottom friction, suggesting that other effects may also influence the near-bed sediment boundary conditions.This research has been supported by NSF
grants CTS-0000675 and OCE-0095834 to Cornell University. This paper
is also a resulting product [R/CCP-9] funded under award NA16RG1645
from the National Sea Grant College Program of U.S. Department of
Commerce’s National Oceanic and Atmospheric Administration to the
Research Foundation of State University of New York on behalf of New
York Sea Grant. The financial supports for Tian-Jian Hsu provided by
Department of Civil and Environmental Engineering, University of Delaware,
and the Coastal Ocean Institute of Woods Hole Oceanographic
Institution are also acknowledged
Leczenie żywieniowe w neurologii — stanowisko interdyscyplinarnej grupy ekspertów
U pacjentów hospitalizowanych z powodu chorób neurologicznych oraz w okresie usprawniania i opieki często stwierdza się zaburzenia o charakterze dysfagii oraz inne zaburzenia i stany kliniczne ograniczające przyjmowanie odpowiedniej ilości składników odżywczych. Może się to przyczynić do utrudnienia leczenia oraz do pogorszenia jego wyniku. Stanowisko interdyscyplinarnej grupy ekspertów wskazuje na znaczenie badań przesiewowych i diagnostyki dysfagii oraz zawiera wytyczne prawidłowej terapii żywieniowej w celu profilaktyki zachłystowego zapalenia płuc, niedożywienia i odwodnienia
Evaluation of the effect of patient education on rates of falls in older hospital patients: Description of a randomised controlled trial
Background. Accidental falls by older patients in hospital are one of the most commonly reported adverse events. Falls after discharge are also common. These falls have enormous physical, psychological and social consequences for older patients, including serious physical injury and reduced quality of life, and are also a source of substantial cost to health systems worldwide. There have been a limited number of randomised controlled trials, mainly using multifactorial interventions, aiming to prevent older people falling whilst inpatients. Trials to date have produced conflicting results and recent meta-analyses highlight that there is still insufficient evidence to clearly identify which interventions may reduce the rate of falls, and falls related injuries, in this population. Methods and design. A prospective randomised controlled trial (n = 1206) is being conducted at two hospitals in Australia. Patients are eligible to be included in the trial if they are over 60 years of age and they, or their family or guardian, give written consent. Participants are randomised into three groups. The control group continues to receive usual care. Both intervention groups receive a specifically designed patient education intervention on minimising falls in addition to usual care. The education is delivered by Digital Video Disc (DVD) and written workbook and aims to promote falls prevention activities by participants. One of the intervention groups also receives follow up education training visits by a health professional. Blinded assessors conduct baseline and discharge assessments and follow up participants for 6 months after discharge. The primary outcome measure is falls by participants in hospital. Secondary outcome measures include falls at home after discharge, knowledge of falls prevention strategies and motivation to engage in falls prevention activities after discharge. All analyses will be based on intention to treat principle. Discussion. This trial will examine the effect of a single intervention (specifically designed patient education) on rates of falls in older patients in hospital and after discharge. The results will provide robust recommendations for clinicians and researchers about the role of patient education in this population. The study has the potential to identify a new intervention that may reduce rates of falls in older hospital patients and could be readily duplicated and applied in a wide range of clinical settings. Trial Registration. ACTRN12608000015347
Turbulent shear stresses and prime velocity distribution in compound channels
The turbulent stresses must be defined to calculate the velocity distributions in open channel flows. In the paper, the turbulent stresses are presented as a sum of the normal and shear turbulent stresses. The normal turbulent stresses act like pressure, i.e., they are isotropic and can be absorbed by the pressure-gradient term in the momentum equations. Therefore, only the shear stresses have to be defined to describe the velocity distribution, e.g., the prime velocity distribution in an open channel flow. The shear turbulent stresses are defined by the 3D mixing length hypothesis. This hypothesis is based on the mixing length tensor (MLT). It is shown how to define the components of MLT for compound channels and how to relate it to the turbulent stress tensor. The components of the MLT are defined based on the concept of the generic mixing length (GML). This concept is presented. Having calculated the generic mixing length, the main components of the MLT as well as the turbulent shear stresses can be calculated. The presented concept is applied to calculate the prime velocity distribution in laboratory open channels with two-stage cross-section. Two channels are considered, one with vertical sidewalls and one with inclined sidewalls. The basic hydrodynamics equations (parabolic approximation of Reynolds equations) together with the turbulence model are solved. The well-known Patankar-Spalding algorithm was used to solve these equations. Some numerical simulations were performed for different components of MLT, i.e. for different structure of turbulence. The results of numerical simulations were compared with the primary velocity distribution measured in the laboratory channel. These comparisons show that the model predicts the velocity field reasonably well
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