Working conditions in South Africa since the end of apartheid a comparison between the agricultural, forestry and mining sectors

International audienc

PATHWAY DETECTION AND GEOMETRICAL DESCRIPTION FROM ALS DATA IN FORESTED MOUNTANEOUS AREA

International audienceIn the last decade, airborne laser scanning (ALS) systems have become an alternative source for the acquisition of altimeter data. Compared to high resolution orthoimages, one of the main advantages of ALS is the ability of the laser beam to penetrate vegetation and reach the ground underneath. Therefore, 3D point clouds are essential data for computing Digital Terrain Models (DTM) in natural and vegetated areas. DTMs are a key product for many applications such as tree detection, flood modelling, archeology or road detection. Indeed, in forested areas, traditional image-based algorithms for road and pathway detection would partially fail due to their occlusion by the canopy cover. Thus, crucial information for forest management and fire prevention such as road width and slope would be misevaluated. This paper deals with road and pathway detection in a complex forested mountaneous area and with their geometrical parameter extraction using lidar data. Firstly, a three-step image-based methodology is proposed to detect road regions. Lidar feature orthoimages are first generated. Then, road seeds are both automatically and semi-automatically detected. And, a region growing algorithm is carried out to retrieve the full pathways from the seeds previously detected. Secondly, these pathways are vectorized using morphological tools, smoothed, and discretized. Finally, 1D sections within the lidar point cloud are successively generated for each point of the pathways to estimate more accurately road widths in 3D. We also retrieve a precise location of the pathway borders and centers, exported as vector data

pH Sensitive visible or SWIR Quantum Dot Nanoprobes using Conformation- Switchable Copolymeric Ligands

International audienceIntracellular and extracellular pH are key parameters in many physiological processes and diseases. For example, the extracellular pH of the tumor micro-environment is slightly more acidic than in healthy tissue. In vivo mapping of the extracellular pH within the tumor would therefore improve our understanding of the tumor physiology. Fluorescent semiconductor quantum dots (QDs) represent interesting probes for in vivo imaging, in particular in the shortwave infrared range (SWIR). Here, pH-sensitive QD nanoprobes are developed using a conformation-switchable surface chemistry. The central fluorescent QD is coated with a copolymer ligand and conjugated to gold nanoparticle quenchers. As the pH decreases from physiological (7.5) to slightly acidic (5.5-6), the copolymer reversibly shrinks, which increases the energy transfer between the QD and the gold quenchers and modulates the QD fluorescence signal. This enables the design of ratiometric QD probes for biological pH ranging emitting in the visible or SWIR range. In addition, these probes can be easily encapsulated and remain functional within ghost erythrocyte membranes, which facilitates their in vivo application

The Stength of Weak cooperation: A Case Study on Flickr

Web 2.0 works with the principle of weak cooperation, where a huge amount of individual contributions build solid and structured sources of data. In this paper, we detail the main properties of this weak cooperation by illustrating them on the photo publication website Flickr, showing the variety of uses producing a rich content and the various procedures devised by Flickr users themselves to select quality. We underlined the interaction between small and heavy users as a specific form of collective production in large social networks communities. We also give the main statistics on the (5M-users, 150M-photos) data basis we worked on for this study, collected from Flickr website using the public API

First record of the invasive Siphonatrophia cupressi (Swain) (Aphididae Aphidini Aphidina) in the Iberian peninsula.

Siphonatrophia cupressi Swain, 1918 has been caught for first time in the Iberian Peninsula in the Arboretum and Botanical Garden of Lleida. Small colonies with apterous and alate individuals were recorded on Cupressus macrocarpa Hartw. The aphid was mainly associated to the as native parasitoid Lysiphlebus testaceipes Cresson, which enhances the role of this parasitoid in potentially preventing outbreaks of the new immigrant aphid   species

Public Opinion Polling and the Millennium Development Goals

Monitoring changes in public awareness and attitudes in rich countries towards aid and other international development policy issues is extremely difficult: due to lack of systematic polling or monitoring, there is no reliable, comparable data across DAC member countries. This paper suggests a way to address this problem: a common questionnaire for all DAC countries to use in their national surveys, centred on the Millennium Development Goals. It sums up the process that led to the setting up of this questionnaire, provides a short analysis of the main methodological issues and brings together three versions, respectively for face-to-face, phone or mail processing. These should allow information and communication professionals, as well as policy makers, to improve the comparability of public opinion surveys in OECD DAC member countries on development and the MDGs, especially if —as proposed by the European Commission’s Directorate General for Development — parts of the questionnaire are included in the next Eurobarometer survey on development across EU member countries (possibly in 2005)

Tracing intensive fish and meat consumption using Zn isotope ratios: evidence from a historical Breton population (Rennes, France)

International audienceHere we report Sr and Zn isotope ratios of teeth of medieval to early modern Breton people a population whose diet is known from historical, archeological and collagen isotope data. Most of the population, buried in the Dominican convent of Rennes, France, consists of parliamentary nobles, wealthy commoners and ecclesiastics, who had a diet rich in animal products. Our aim is to assess how the Zn isotope ratios of their teeth compare to those of other French historical populations previously studied, which were characterized by cereal-based diets, and those of modern French individuals, who daily eat animal products. We describe a clear offset (∼0.35‰) between local and non-local human individuals in Zn isotope ratios. The δ 66 Zn tooth values of local individuals overlap that of modern French people, and are lower than those of local carnivores. Non-local δ 66 Zn values are similar to those of historical individuals analyzed previously. We conclude the lower Zn isotope ratios of local humans relative to the associated fauna can be explained by the consumption of carnivorous fish and pork, in agreement with historical, zooarchaeological and collagen (C, N, S) isotope data. Zn isotopes could therefore be a tracer of fish and/or substantial meat consumption in ancient populations