Allometric scaling predicts preferences for burned patches in a guild of East African grazers

The high herbivore diversity in savanna systems has been attributed to the inherent spatial and temporal heterogeneity related to the quantity and quality of food resources. Allometric scaling predicts that smaller-bodied grazers rely on higher quality forage than larger-bodied grazers. We replicated burns at varying scales in an East African savanna and measured visitation by an entire guild of larger grazers ranging in size from hare to elephant. We found a strong negative relationship between burn preference and body mass with foregut fermenters preferring burns to a greater degree than hindgut fermenters. Burns with higher quality forage were preferred more than burns with lower quality forage by small-bodied grazers, while the opposite was true for large-bodied grazers. Our results represent some of the first experimental evidence demonstrating the importance of body size in predicting how large herbivores respond to fire-induced changes in plant quality and quantity.     

The Impact of Biodegradable Plastics in the Properties of Recycled Polyethylene Terephthalate

Journal of Polymers and the Environment - Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some...     

Occupational accidents model based on risk–injury affinity groups

This article sets outs a generalized utility model for the diagnosis and prediction of accidents among the Spanish workforce. Based on observational data classified into a risk–injury contingency table (19 × 19), we have summarized the accident rate of all Spanish companies over an 11-year period (75,19,732 accidents). By using correspondence analysis a structure composed of three axes can be obtained, the combination of which identifies three separate risk and injury groups, which we use as a general Spanish pattern. The relationships of greater affinity or likelihood amongst the risks and injuries identified in the pattern facilitate decision-making at the risk-assessment stage in Spanish companies. Each risk–injury group has its own characteristics, interpretable within the phenomenological framework of the accident.The main advantage of this model is its potential application to any other country and the feasibility of contrasting results from different countries. One limiting factor, however, is that the model currently lacks a common classification frame for risks and injuries which would enhance this contrast. The aim of this model is to automatically manage work-related accidents at a national level.     

Eco-Compatible Use of Olive Husk as Filler in Thermoplastic Composites

A study on the possibility of recycling waste materials, such as olive husk, the solid phase derived from an olive oil mill, in blend with thermoplastic polymers to produce new materials for manufacturer of, for example, containers and formworks, has been carried out. The present paper describes the methodology used for the preparation and the characterization of composite samples prepared by mixing various percentages of olive husk and polypropylene. A screening on the chemical-physical characteristics of the olive husk is reported, as well as a set of tests applied to evaluate the mechanical properties of the manufactured products obtained.     

Global burned-land estimation in Latin America using MODIS composite data.

This paper presents results of the AQL2004 project, which has been develope within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, U.S.A.) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba, Colombia, Bolivia, and Venezuela. Burned areas were found in most land covers; herbaceous vegetation (savannas and grasslands) presented the highest proportions of burned area, while perennial forest had the lowest proportions. The importance of croplands in the total burned area should be taken with reserve, since this cover presented the highest commission errors. The importance of generating systematic products of burned land areas for different ecological processes is emphasized.     

Present forest biodiversity patterns in france related to former Roman agriculture

Combined archaeological and ecological investigations in a large ancient oak forest in Central France have revealed a dense network of ancient human settlements dating from the Roman period. We demonstrate a strong correlation between present-day forest plant diversity patterns and the location of Roman farm buildings. Plant species richness strongly increases toward the center of the settlements, and the frequency of neutrophilous and nitrogen-demanding species is higher. This pattern is paralleled by an increase in soil pH, available P, and delta(15)N, indicating the long-term impact of former agricultural practices on forest biogeochemical cycles. These extensive observations in a forested region on acid soils complement and confirm previous results from a single Roman settlement on limestone. Ancient Roman agricultural systems are increasingly being identified in contemporary French forests; the broad extent and long-lasting effects of previous cultivation shown in this study require that land-use history be considered as a primary control over biodiversity variations in many forest landscapes, even after millennia of abandonment.     

Ethical issues concerning potential global climate change on food production

Burning fossil fuel in the North American continent contributes more to the CO₂ global warming problem than in any other continent. The resulting climate changes are expected to alter food production. The overall changes in temperature, moisture, carbon dioxide, insect pests, plant pathogens, and weeds associated with global warming are projected to reduce food production in North America. However, in Africa, the projected slight rise in rainfall is encouraging, especially since Africa already suffers from severe shortages of rainfall. For all regions, a reduction in fossil fuel burning is vital. Adoption of sound ecological resource management, especially soil and water conservation and the prevention of deforestation, is important. Together, these steps will benefit agriculture, the environment, farmers, and society as a whole.     

Intracellular localization and binding of technetium-95m in the seastar Marthasterias glacialis

The subcellular distribution of technetium was studied using the seastar Marthasterias glacialis which had previously ingested prey labelled with ^95mTc either as pertechnetate (VII) or in the reduced state (IV). The majority of the Tc [98% (IV) and 96% (VII)] was taken up and retained in the pyloric caeca, the gland responsible for digestive and food storage processes. Differential centrifugation and separation techniques have demonstrated that, at the subcellular level, technetium in the pyloric caeca was largely associated with the lysosomes. ^95mTc (IV) was distributed between the lysosomes and the soluble fraction to roughly the same degree, whereas pertechnetate was more strongly associated with the lysosomal fraction. Chromatography of the cytosol by gel filtration indicated the presence of two distinct protein compounds which were responsible for binding virtually all of the technetium in the soluble fraction. Technetium had a greater relative affinity for the low molecular weight compound, more so for Tc (VII) than for Tc (IV). This anionic protein had an apparent molecular weight of approximately 10 000, and thus may play a role in metal detoxification mechanisms at the cellular level.     

Intracellular digestion in two sublittoral populations of Ostrea edulis (Lamellibranchia)

The rhythmicity of intracellular digestion was examined in two sublittoral populations of Ostrea edulis L. On the West coast of Ireland. During 12 h cycles at each station, 20 oysters were collected each hour, grouped as sub-samples of 5, facing each of the 4 cardinal points of the compass. A segment of digestive diverticula from each oyster was examined histologically and classified according to the digestive phases of the tubules. Oysters at both stations exhibited fluctuations in digestive activity which were not correlated with tidal ebb and flow nor with orientation to tidal currents. A relationship between variations in suspended particulate matter concentration in the water body and digestion is proposed. It is suggested that increases in the levels of particulate matter, by stimulating feeding, cause a significant increase in the proportion of absorptive-phase tubules 4 to 6 h later.