Differences in Walking Pattern during 6-Min Walk Test between Patients with COPD and Healthy Subjects

BACKGROUND: To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. METHODOLOGY/PRINCIPAL FINDINGS: 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%). CONCLUSIONS/SIGNIFICANCE: COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD

The Southern African Regional Science Initiative (SAFARI 2000): Overview of the Dry Season Field Campaign

The Southern African Regional Science Initiative (SAFARI 2000) is an international science project investigating the earth-atmosphere-human system in southern Africa. The programme was conducted over a two-year period from March 1999 to March 2001. The dry season field campaign (August-September 2000) was the most intensive activity and involved over 200 scientists from eighteen countries. The main objectives were to characterize and quantify biogenic, pyrogenic and anthropogenic aerosol and trace gas emissions and their transport and transformations in the atmosphere, and to validate NASA\u27s Earth Observing System\u27s satellite Terra within a scientific context. Five aircraft - two South African Weather Service Aerocommanders, the University of Washington\u27s CV-580, the U.K. Meteorological Office\u27s C-130, and NASA\u27s ER-2-with different altitude capabilities, participated in the campaign. Additional airborne sampling of southern African air masses, that had moved downwind of the subcontinent, was conducted by the CSIRO over Australia. Multiple observations were made in various geographical sectors under different synoptic conditions. Airborne missions were designed to optimize the value of synchronous over-flights of the Terra satellite platform, above regional ground validation and science targets. Numerous smaller-scale ground validation activities took place throughout the subcontinent during the campaign period

Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach

Estimations of available fuelwood resources in communal savanna woodlands are widely based on conventional terrestrial and optical remote sensing approaches, which are constrained by limited geographic footprints and the use of leaf area indices and normalised difference vegetation indices, as surrogates for above ground biomass. As a result, reliable information about the location and estimated quantities of available woody biomass is scarce at local, national and global scales. Recent developments have shown that classification of backscatter information contained in full polarimetric radar retrievals from satellite borne sensors can discriminate between woody and non-woody vegetation. The intensity of the backscattered signal has been shown to be sensitive to above ground biomass density. However, no such studies have been reported across African savanna woodlands. This paper presents a study which used full polarimetric ALOS PALSAR retrievals to map and quantify fuelwood resources in communal savanna woodland in Welverdiend village, South Africa. Unsupervised entropy/alpha angle Wishart classification and maximum likelihood classification procedures are used to characterise the scattering classes from the ALOS PALSAR retrievals into eight major terrain scattering mechanisms. Five vegetation classes (random anisotropic, forest double bounce, vegetation, dihedral and dipole) are identified that are closely related to backscattering from woody vegetation components. Correlations between backscatter intensities acquired under dry and wet conditions with above-ground biomass densities estimated from field surveys are investigated to derive equations for predicting biomass densities. The regression analysis supports findings of similar studies where the HV backscatter intensity showed moderately strong relationship (R2>0.6) with above ground biomass densities. The inverted regression equations were used to estimate the biomass densities for areas covered with woody vegetation. Knowledge about the location and distribution of woody biomass has significant implications for fuelwood management and carbon sequestration initiatives. A combination of woodland management interventions, coupled with the transition to modern energy sources, has the potential of turning communal woodlands into carbon sinks

The global alliance for clean cookstoves: implications for South Africa

The purpose of this paper is to discuss the newly launched Global Alliance for Clean Cookstoves with the aim of highlighting the opportunities that it represents for South Africa. The paper argues that South Africa’s participation in the Alliance could support the developmental objectives of the country including: addressing equity issues related to energy poverty and health; supporting poverty alleviation efforts; supporting the Government’s constitutional commitments on clean air; and developing an innovative research, development and manufacturing sector. It further cites key lessons that South Africa can learn from Peru’s efforts to address indoor air pollution and concludes with a set of recommendations