Assessment of global bioenergy potentials

So far, various studies assessed global biomass potentials and came up with widely varying results. Existing potential estimates range from 0 EJ/a up to more than 1,550 EJ/a which corresponds to about three times the current global primary energy consumption. This paper provides an overview of the available research on bioenergy potentials and reviews the different assessments qualitative way with the objective to interpret previous research in an integrated way. In the context of this paper we understand bioenergy as energy from biomass sources including energy crops, residues, byproducts and wastes from agriculture, forestry, food production and waste management. In this review special attention was paid to the difference between residue and energy potentials, land availability estimates, and the geographical resolution of existing potential estimates. The majority of studies concentrate on energy crop potentials retrieved from surplus agricultural land and only few publications assess global potentials separated by different world regions. It results that land allocated to the exclusive production of energy crops varies from 0 to 7,000 ha, depending on land category and scenario assumptions. Only a small number of available potential assessments consider residue potentials as well as energy crop potentials from degraded land. Future energy crop potentials are assumed to vary in the mean from 200 to 600 EJ/yr. In contrast residue potentials are expected to contribute between 62 and 325 EJ/yr. The highest potentials are assigned to Asia, Africa and South America while Europe, North America and the Pacific region contribute minor parts to the global potential.     

Relaxation algorithms to find Nash equilibria with economic applications

Recent theoretical studies have shown that a relaxation algorithm can be used to find noncooperative equilibria of synchronous infinite games with nonlinear payoff functions and coupled constraints. In this study, we introduce an improvement to the algorithm, such as the steepest-descent step-size control, for which the convergence of the algorithm is proved. The algorithm is then tested on several economic applications. In particular, a River Basin Pollution problem is considered where coupled environmental constraints are crucial for the relevant model definition. Numerical runs demonstrate fast convergence of the algorithm for a wide range of parameters. This revised version was published online in July 2006 with corrections to the Cover Date.     

Gravity orientation in social wasp comb cells (Vespinae) and the possible role of embedded minerals

Social wasps and hornets maintain their nest in the dark. The building of the combs by all Vespinae is always in the direction of the gravitational force of Earth, and in each cell's ceiling, at least one 'keystone' is embedded and fastened by saliva. The sensory mechanisms that enable both building of sizeable symmetrical combs and nursing of the brood in the darkness merit investigation, and the aim of the present study was to identify and characterize the 'keystones' that exist in the ceiling and in the walls of the social wasp comb cells. Bio-ferrography was used to isolate magnetic particles on slides. These slides, as well as original cells, were analyzed in an environmental scanning electron microscope by a variety of analytical tools. It was found that both the roof and the walls of each comb cell bear minerals, like ferrites, as well as Ti and Zr. The latter two elements are less abundant in the soil around the nest. Ti and Zr are known to reflect infrared (IR) light. IR imaging showed a thermoregulatory center in the dorsal thorax of the adult Oriental hornet. It is not known yet whether these insects can sense IR light.     

Effects on non-human species inhabiting areas with enhanced level of natural radioactivity in the north of Russia: a review

Results of long-term radioecological investigations in areas with an enhanced level of natural radioactivity in the north of Russia are summarized. Deleterious changes within animal and plant populations inhabiting areas with an enhanced level of natural radioactivity in the Komi Republic were revealed. These changes are expressed in enhanced levels of mutagenesis, destructive processes in the tissues of animals, disturbances of reproductive functions and reduced offspring viability. Compensatory processes, resulting in animal and plant survival under extremely adverse conditions of radium and uranium-radium contamination, were observed as well. However, obvious signs of adaptation failed to be detected. The findings suggest that adverse somatic and genetic effects are possible in plants and animals in the dose range observed at sites with an enhanced level of natural radioactivity. In contrast, different plant species inhabiting an area with an enhanced level of natural radioactivity in the taiga zone of the Sakha Republic (Yakutia) reveal a stimulation of growth processes, photosynthesis, endogenous low molecular weight antioxidant synthesis as well as adaptive response. It is apparent from the data presented that naturally occurring differences in terrestrial radiation level could be of genetic and ecological consequence.     

Novel approach to monitoring of the soil biological quality

In this study, a new approach to interpretation of results of the simple microbial biomass and respiration measurements in the soil microbiology is proposed. The principle is based on eight basal and derived microbial parameters, which are standardized and then plotted into sunray plots. The output is visual presentation of one plot for each soil, which makes possible the relative comparison and evaluation of soils in the monitored set. Problems of soil microbiology, such as the lack of benchmarking and reference values, can be avoided by using the proposed method. We found that eight parameters provide enough information for evaluation of the status of the soil microorganisms and, thus, for evaluation of the soil biological quality. The usage of rare parameters (potential respiration PR, ratio of potential and basal respiration PR/BR, biomass-specific potential respiration PR/C(bio), available organic carbon C(ext), and biomass-specific available organic carbon C(ext)/C(bio)) can be recommended, besides classical and well-known parameters (microbial biomass C(bio), basal respiration BR, metabolic coefficient qCO(2)). The combination of basal parameters and derived coefficients can also extend our knowledge about the condition of the soil microorganisms. In monitoring the case studies presented, we observed that soils evaluated to possess good biological quality displayed generally higher values of organic carbon, total nitrogen, clay, and cation exchange capacity. The soils of good biological quality can display higher levels of contaminants. This is probably related with the higher content of organic carbon and clay in these soils.     

Paternity covaries with laying and hatching order in the collared flycatcher Ficedula albicollis

Females in most bird species engage in extra-pair copulations. Although this behaviour is widespread, benefits for females of doing so are less understood. The most widely accepted hypothesis is that they improve their previous choice of social partner and gain genetic benefits for their offspring. Some evidence for this comes from studies that find that extra-pair young (EPY) have greater fitness than their half-sibs. However, this might be also caused by maternal, non-genetic effect, a possibility that remains largely untested. Here we test whether EPY are laid in larger eggs or eggs laid early in the laying sequence in the collared flycatcher (Ficedula albicollis). The size of eggs bearing EPY and within-pair young (WPY) did not differ, however, EPY were laid in early eggs and consequently hatched earlier than WPY. As hatching asynchrony is a strong determinant of offspring size and survival in many species, including collared flycatcher, our results suggest that a caution is needed when paternal genetic effects are to be inferred from comparison of naturally occurring half-sibs.     

PCDDs, PCDFs and dioxin-like PCBs in food of animal origin (Slovakia)

The levels of 17 toxic polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and 12 non-ortho and mono-ortho polychlorinated biphenyls (PCBs) in 73 foodstuff samples of animal origin collected from shops and small farms in selected districts of Slovak Republic are presented in this paper. The concentrations expressed as WHO-TEQ in analysed samples ranged for PCDDs/PCDFs from 0.25 pg/g fat in pork to 75 pg/g fat in cod liver. The TEQ concentrations of non-ortho PCBs were between 0.007 and 181 pg/g fat and mono-ortho PCBs between 0.0083 and 66.5 pg/g fat. The mean concentrations in freshwater fish and imported species of marine fish were 0.089 pg TEQ/g fresh weight for PCDDs/PCDFs, 0.17 pg TEQ/g fresh weight for non-ortho PCBs and 0.034 pg TEQ/g fresh weight for mono-ortho PCBs. The mean total concentration of PCDDs/PCDFs and dioxin-like PCBs in samples of infant milk formula imported from EU countries was 0.98 pg TEQ/g fat.     

What drives visitors to tourist sites to choose “green” accommodation facilities?

Environment, Development and Sustainability - Our aim is to determine the factors influencing a visitor’s decision to stay in a green accommodation facility. Visitors from six tourist sites...