Using Landsat Imagery to Analyse Land Cover Change in the Njoro Watershed, Kenya

In developing nations where resources are scarce and increased population pressures create stress on available resources, methods are needed to examine effects of human migration and resultant changes in land cover. Widespread availability and low cost of remotely sensed imagery and Geographic Information Systems (GIS) are making such methods a reality to develop quantitative resource mapping and land cover change detection in developing nations (Sheng et al., 1997). However, difficulties arise in tropical regions when trying to analyse traditional vegetation bands (Bands 3 and 4), or indices such as NDVI because saturated pixels limit spectral distinction

Impact of Land Use on Water Quality in River Njoro Watershed, Kenya

Water resources within the River Njoro watershed have become degraded due to high population growth rate and change in land use upsetting environmental stability. Land cover classification using Landsat images (Baldyga et al., 2004) shows loss of about 20% of forested areas between 1986 and 2003 in the watershed. The forested and large-scale farm areas have been converted mainly into small-scale mixed agriculture and human settlements. These changes have impacted negatively on the ecological integrity and hydrologic processes in the watershed (Shivoga, 2001) but little is known about the influence of specific land uses on water quality of the river

Transition phenomena in unstably stratified turbulent flows

We study experimentally and theoretically transition phenomena caused by the external forcing from Rayleigh-Benard convection with the large-scale circulation (LSC) to the limiting regime of unstably stratified turbulent flow without LSC whereby the temperature field behaves like a passive scalar. In the experiments we use the Rayleigh-B\'enard apparatus with an additional source of turbulence produced by two oscillating grids located nearby the side walls of the chamber. When the frequency of the grid oscillations is larger than 2 Hz, the large-scale circulation (LSC) in turbulent convection is destroyed, and the destruction of the LSC is accompanied by a strong change of the mean temperature distribution. However, in all regimes of the unstably stratified turbulent flow the ratio $\big[(\ell_x \nabla_x T)^2 + (\ell_y \nabla_y T)^2 + (\ell_z \nabla_z T)^2\big] /$ varies slightly (even in the range of parameters whereby the behaviour of the temperature field is different from that of the passive scalar). Here $\ell_i$ are the integral scales of turbulence along x, y, z directions, T and \theta are the mean and fluctuating parts of the fluid temperature. At all frequencies of the grid oscillations we have detected the long-term nonlinear oscillations of the mean temperature. The theoretical predictions based on the budget equations for turbulent kinetic energy, turbulent temperature fluctuations and turbulent heat flux, are in agreement with the experimental results.Comment: 14 pages, 14 figures, REVTEX4-1, revised versio

coreNASH: Multi-stakeholder Consensus on Core Outcomes for Decision Making About Nonalcoholic Steatohepatitis Treatment

The increasing prevalence and burden of nonalcoholic steatohepatitis (NASH) has spurred the development of new treatments and a need to consider outcomes used for NASH treatment decision making. Development of a NASH core outcome set (COS) can help prioritize outcomes of highest importance by incorporating the perspectives from a variety of decision makers. coreNASH was an initiative to develop a COS for NASH using a modified Delphi consensus process with a multi-stakeholder voting panel. A candidate outcome list was created based on a literature review and key informant interviews. The candidate outcome list was then condensed and prioritized through three rounds of online voting and through discussion at an in-person meeting. Outcomes were retained or eliminated based on predetermined consensus criteria, which included special weighting of patients’ opinions in the first two voting rounds. The coreNASH Delphi panel included 53 participants (7 patients, 10 clinicians and researchers, 7 health technology assessors, 22 industry representatives, 2 regulators, and 5 payers) who considered outcomes for two NASH-related COS: one for NASH without cirrhosis (F2-F3) and one for NASH with cirrhosis (F4). The initial candidate outcome list for both disease stages included 86 outcomes. The panel agreed on including two core outcomes for NASH without cirrhosis and nine core outcomes for NASH with cirrhosis in the COS. Conclusion: A consensus-based COS has been developed that can be used across the life cycle of NASH treatments. Outcomes included can contribute to decision making for regulatory, market access, and on-market decision making. Including the coreNASH COS in clinical development programs will facilitate improved comparisons and help decision makers assess the value of new products

Inter-connection between land use/land cover change and herders’/farmers’ livestock feed resource management strategies: a case study from three Ethiopian eco-environments

AbstractWe assessed land use/land cover changes from remotely sensed satellite imagery and compared this with community perceptions on availability/use of livestock feed resources and feed deficit management strategies since the 1973s in three districts representing the pastoral, agro-pastoral and mixed crop-livestock eco-environments of Ethiopia. We found that land use/land cover changes are proceeding in all eco-environments and that transitions are from grasslands, and forest lands to bush/shrub lands and crop lands in the pastoral site (Liben), from bush/shrub lands and grasslands to crop lands in agro-pastoral site (Mieso) and from bush/shrub lands, forest lands and grasslands to crop lands in the mixed crop-livestock site (Tiyo). The changes significantly affected livestock feed resources and feed deficit management strategies available to households. Over the last 30–40 years, grazing resources available to livestock keepers have been declining with resultant increase in the contribution of crop residues and other feeds from crop lands (weeds and crop thinnings) as compared to feeds from grasslands. The feed deficit management strategies of households are also changing significantly from mobility to herd management and feed conservation in the pastoral areas; from mobility to feed conservation and purchasing of feed in the agro-pastoral areas and from transhumance to feed conservation and purchase of feed in the mixed crop-livestock areas. Hence feed resources and their availability vary with time and eco-environments indicating the need for the development of eco-environment/site specific feed management strategies in order to support productive stock in the study areas and similar eco-environments

Particle formation by mixing with supercritical antisolvent at high Reynolds numbers.

NoA precipitation process is considered in which completely miscible solution and supercritical antisolvent are passed through premixing and diluting zones of a turbulent flow. The influence of flow velocity on particle size and nuclei concentration is discussed in terms of mixing and precipitation time constants and their supersaturation dependencies. The proposed model allowed the major process parameters such as supersaturation profile, mixed fluid fraction and mean particle size to be calculated and compared with experimental data. For the crystallization system paracetamol/ethanol/CO2 studied, the supersaturation profile becomes established at Re104. The particle size and shape are defined, firstly, by increase of supersaturation and relative volume of mixed (on molecular scale) fluid with increase of flow velocity and, secondly, by decrease of residence time available for nucleation with increase of flow velocity. These competitive processes can result in minimum particle size at a defined flow rate