The effect of occupational-related low back pain on the functional activities among manual workers in construction companies

INTRODUCTION: Low back pain is the most prevalent musculoskeletal condition and one of the most common causes of disability in the world. The disability resulting from low back pain continues to plague the construction industry leading to absenteeism and early retirement among construction manual workers. PURPOSE: The aim of the review was to explore global literature concerning the effect of occupational-related low back pain on the functional activities among manual workers in construction companies. METHOD: A retrospective search of articles published from January 2000 to April 2010. The following electronic data bases, Google Scholar, Academic search premier, CINAHL, ERIC, Health source-consumer Edition, Health source: Nursing/Academic Edition, Master FILE Premier, MEDLINE, MLA Directory of Periodicals, Science direct, MLA International Bibliography, Pre-CiNAHL and PubMed were individually searched using specifically developed search strategies. Methodological quality was evaluated using the Critical Appraisal Skills Programme (CASP) tool and was done by two independent reviewers. RESULTS: The search yielded eleven articles of sound quality. There is evidence that a high percentage of construction workers suffer permanent disability and fail to return to work forcing them to go into early retirement due to occupational related low back pain. The cohort studies have shown that poor performance, reduction in productivity, restrictions on usual activity and participation and incurring high medical costs all pose a challenge to construction manual workers and their employers as a result of occupational related low back. CONCLUSION: The findings support that occupational related low back pain is a challenge among construction manual workers causing serious disability. Further well designed research in Africa into the most effective strategies to prevent and manage occupational related low back pain among construction manual workers is needed

Modelagem de preços de provedores de IaaS utilizando regressão múltipla

Uma alternativa para usuários reduzirem custos de aquisição e manutenção de infraestrutura computacional para desenvolver, implementar e executar suas aplicações é a computação em nuvem. Os serviços de computação em nuvem são oferecidos por provedores e podem ser classificados em três modalidades: Platform-as-a-Service (PaaS), Software-as-a-Service (SaaS) e Infrastructure-as-a-Service (IaaS). Em IaaS, os provedores oferecem os serviços divididos em instâncias e o usuário tem à disposição uma máquina virtual com os recursos computacionais que desejar a um determinado valor. O principal desafio enfrentado pelas empresas é escolher, além do provedor, a instância que melhor se adapta as suas necessidades. Frequentemente, estas empresas precisam de uma grande infraestrutura computacional para gerir e aperfeiçoar seus processos de negócio e, diante do alto custo para manter uma infraestrutura local, têm migrado suas aplicações para a nuvem. Este trabalho busca fornecer subsídios capazes de auxiliar as empresas no processo de seleção do melhor provedor/instância para implantar e executar suas soluções de integração na nuvem. Para isso, um estudo preliminar para a elaboração de uma nova proposta de modelagem dos preços das instâncias de máquinas virtuais usando regressão linear é apresentado. Nesta abordagem são considerados os provedores Amazon EC2, Google Compute Engine e Microsoft Windows Azure.info:eu-repo/semantics/acceptedVersio

High-fidelity simulations of gravity currents using a high-order finite-difference spectral vanishing viscosity approach

This numerical work investigates the potential of a high-order finite-difference spectral vanishing viscosity approach to simulate gravity currents at high Reynolds numbers. The method introduces targeted numerical dissipation at small scales through altering the discretisation of the second derivatives of the viscous terms in the incompressible Navier-Stokes equations to mimic the spectral vanishing viscosity (SVV) operator, originally designed for the regularisation of spectral element method (SEM) solutions of pure advection problems. Using a sixth-order accurate finite-difference scheme, the adoption of the SVV method is straightforward and comes with a negligible additional computational cost. In order to assess the ability of this high-order finite-difference spectral vanishing viscosity approach, we performed large-eddy simulations (LES) of a gravity current in a channelised lock-exchange set-up with our SVV model and with the well-known explicit static and dynamic Smagorinsky sub-grid scale (SGS) models. The obtained data are compared with a direct numerical simulation (DNS) based on more than 800 million mesh nodes, and with experimental measurements. A framework for the energy budget is introduced to investigate the behaviour of the gravity current. First, it is found that the DNS is in good agreement with the experimental data for the evolution of the front location and velocity field as well as for the stirring and mixing inside the gravity current. Secondly, the LES performed with less than 0.4% of the total number of mesh nodes compared to the DNS, can reproduce the main features of the gravity currents, with the SVV model yielding slightly more accurate results. It is also found that the dynamic Smagorinsky model performs better than its static version. For the present study, the static and dynamic Smagorinsky models are 1.8 and 2.5 times more expensive than the SVV model, because the latter does not require the calculation of explicit SGS terms in the Navier-Stokes equations nor spatial filtering operations

Direct Photons at RHIC

The PHENIX experiment has measured direct photons in $\sqrt{s_{NN}} = 200$ GeV Au+Au collisions and p+p collisions. The fraction of photons due to direct production in Au+Au collisions is shown as a function of $p_T$ and centrality. This measurement is compared with expectation from pQCD calculations. Other possible sources of direct photons are discussed.Comment: 7 pages, 5 figures, presented at Hot Quarks 2004, Taos, N

Precision Masses of the low-mass binary system GJ 623

We have used Aperture Masking Interferometry and Adaptive Optics (AO) at the Palomar 200'' to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 years combined with a decade of radial velocity measurements constrain all orbital parameters of the GJ 623 binary system accurately enough to critically challenge the models. The dynamical masses measured are m_{1}=0.371\pm0.015 M_{\sun} (4%) and m_{2}=0.115\pm0.0023 M_{\sun} (2%) for the primary and the secondary respectively. Models are not consistent with color and mass, requiring very low metallicities.Comment: 7 pages, 5 figures. Accepted for Ap

Xcompact3D: An open-source framework for solving turbulence problems on a Cartesian mesh

Xcompact3D is a Fortran 90–95 open-source framework designed for fast and accurate simulations of turbulent flows, targeting CPU-based supercomputers. It is an evolution of the flow solver Incompact3D which was initially designed in France in the mid-90’s for serial processors to solve the incompressible Navier–Stokes equations. Incompact3D was then ported to parallel High Performance Computing (HPC) systems in the early 2010’s. Very recently the capabilities of Incompact3D have been extended so that it can now tackle more flow regimes (from incompressible flows to compressible flows at low Mach numbers), resulting in the design of a new user-friendly framework called Xcompact3D. The present manuscript presents an overview of Xcompact3D with a particular focus on its functionalities, its ready-to-run simulations and a few case studies to demonstrate its impact