The influence of soil community density on plant-soil feedbacks: An important unknown in plant invasion

Plant-soil feedbacks have been implicated in several successful plant invasions. However, simple identification of a feedback alone may not be enough to establish feedbacks as a mechanism behind plant invasion. I suggest that the relationship between soil community density and plant growth is an important unknown that strongly influences the impact of plant-soil feedbacks. I developed a mathematical model of two-plant species competition with plant-soil feedbacks. Each plant species obligately generates its own soil community. Each soil community then influences both plant species’ growth. The model allows for every possible combination of positive and negative effects of the soil community on plant growth. I model the relationship between soil community density and plant growth with non-linear functional responses. I use a range of plant competitive abilities and feedback scenarios from the literature to explore how different functional responses influence the outcome of plant competition. Sensitivity analysis of the model reveals that altering the relationship between feedback strength and soil community development can reverse the outcome of plant competition. Analysis of the model also shows how the importance of different feedback scenarios depends on the strength of plant competition.     

Climate change impacts,vulnerability and adaptive capacity of the electrical energy sector in Cyprus

The purpose of this study was to investigate the climate change impacts, vulnerability and adaptive capacity of the electrical energy sector in Cyprus. Spatial vulnerability of the island was assessed using the degree-day indicator to investigate heating and cooling demands in the near future using daily temperature projections from regional climate models (RCMs). Using daily electrical energy consumption data for the present climate, an impact model linking consumption and temperature was constructed and this relationship was projected to the future climate using the data from the RCMs and assuming the same technology use. Our impact model results showed that for the period between November and April (‘cold period’), a decreasing trend in electrical energy consumption is evident due to warmer conditions in the near future, while for the period between May and October (‘warm period’), an increasing trend in electricity consumption is evident as warmer conditions dominate by 2050. Regarding the spatial vulnerability assessment, the cooling degree-day indicator testified that major increases in cooling demand, between 100 and 200 degree-days, are expected in inland and southern regions during the summer in the near future. In addition, increases of about 20–50 degree-days are anticipated during autumn. Conversely, energy demand for heating is projected to decrease during spring and winter, especially in the higher elevation parts of the island. More precisely, reductions of about 30–75 degree-days are projected during spring, while greater reductions of about 60–90 degree-days are expected during winter in heating demand, especially for in the near future. The ability of the energy sector to adapt and follow these changes was deemed to be satisfactory reducing the overall vulnerability of the sector to future climate change.     

Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels—the FuelHealth project

Epidemiological data indicate that exposure to diesel exhaust particles (DEPs) from traffic emissions is associated with higher risk of morbidity and mortality related to cardiovascular and pulmonary diseases, accelerated progression of atherosclerotic plaques, and possible lung cancer. While the impact of DEPs from combustion of fossil diesel fuel on human health has been extensively studied, current knowledge of DEPs from combustion of biofuels provides limited and inconsistent information about its mutagenicity and genotoxicity, as well as possible adverse health risks. The objective of the present work was to compare the genotoxicity of DEPs from combustion of two first-generation fuels, 7% fatty acid methyl esters (FAME) (B7) and 20% FAME (B20), and a second-generation 20% FAME/hydrotreated vegetable oil (SHB: synthetic hydrocarbon biofuel) fuel. Our results revealed that particulate engine emissions from each type of biodiesel fuel induced genotoxic effects in BEAS-2B and A549 cells, manifested as the increased levels of single-strand breaks, the increased frequencies of micronuclei, or the deregulated expression of genes involved in DNA damage signaling pathways. We also found that none of the tested DEPs showed the induction of oxidative DNA damage and the gamma-H2AX-detectable double-strand breaks. The most pronounced differences concerning the tested particles were observed for the induction of single-strand breaks, with the greatest genotoxicity being associated with the B7-derived DEPs. The differences in other effects between DEPs from the different biodiesel blend percentage and biodiesel feedstock were also observed, but the magnitude of these variations was limited.     

六百年巍巍紫禁城

说起北京故宫,可能会引起许多人的向往,确实,我也想去故宫看看,今年,正逢故宫建成600年之际,我专程走进了北京故宫,去看看皇帝的龙椅,看看那万人朝奉的大殿,以及后宫是否真的像电视剧里面的那样.那红色的城墙,高高的大柱仍然还在传达着皇家的威严,台阶上的太和殿似乎还是在位皇帝接受天下臣民朝拜而准备的……     

Zeolites relieves inhibitory stress from high concentrations of long chain fatty acids

Protein and fat rich slaughterhouse waste is a very attractive waste stream for the production of biogas because of the high biochemical methane potential of the substrate. The material has however some drawbacks as the sole material for biogas production due to the production of several process disturbing metabolites such as ammonia, sulfides and long chain fatty acids. We can in this work present results that show that zeolites have the potential to relieve inhibitory stress from the presence of long chain fatty acids. Moreover, the results strongly indicate that it is mainly acetic acid consumers that are most negatively affected by long chain fatty acids and that the mechanism of stress relief is an adsorption of long chain fatty acids to the zeolites. In addition to this, it is shown that the effect is immediate and that only a small amount of zeolites is necessary to cancel the inhibitory effect of long chain fatty acids.     

In and Of the World? Christian Theological Anthropology and Environmental Ethics

Mainstream currents within Christianity havelong insisted that humans, among all creatures, areneither fully identified with their physical bodiesnor fully at home on earth. This essay outlines theparticular characteristics of Christian notions ofhuman nature and the implications of this separationfor environmental ethics. It then examines recentefforts to correct some damaging aspects oftraditional Christian understandings of humanity'splace in nature, especially the notions of physicalembodiment and human embeddedment in earth. Theprimary goal of the essay is not to offer acomprehensive evaluation of Christian thinking aboutnature but rather to identify theological anthropologyas a crucial dimension of, and problem for, Christianenvironmental ethics.     

The evolution of community water governance in Uchira, Tanzania: The implications for equality of access, sustainability and effectiveness

Community participation, ownership and cost sharing are key components of Tanzania's water policy, in common with the broad international consensus on water governance. However these policy goals are difficult to achieve, beset with paradoxes and their benefits may be overstated, both in terms of efficiency of resource management and equality of outcomes. This article draws on longitudinal ethnographic research of a village water supply in Tanzania to explore two issues: the contested nature of community ownership and the complex evolution of a ‘community‐owned’ institution. The evidence from the Uchira Water Users Association leads us to question some of the simplistic assumptions made concerning the capacity of local communities to manage service delivery and to balance equity and sustainability principles. The limitations of ‘bottom‐up’ and demand led approaches need to be recognised without discrediting their potential for challenging inequalities. The article concludes with a consideration of some of the tensions in community‐driven development, which raises some important questions about the role of the State and external agencies in setting and enforcing equity criteria in community‐managed initiatives.     

Metal distribution and stability in constructed wetland sediment

The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb.     

Farmers' Choices: Management Practices to Reduce Nutrient Leakage within a Swedish Catchment

This paper analyses farmers' strategies on management practices for the reduction of nutrient releases, within a Swedish catchment. The main objective of the European Union water framework directive is to obtain good ecological water quality, and the approach is specifically stipulated to be catchment-based. Eutrophication is generally stated as the main environmental problem in water management and agricultural production is the major cause of nutrient leakage. The analysis concentrates on current agricultural management practices to reduce nutrient leakage. Farmers are beginning to experience a new awareness about nutrient use and see manure as a resource instead of a waste product. Further, those factors that are decisive for decision making are investigated, including information sources. The farm economy, the level of ecological knowledge and regulations illustrate the main obstacles linked to decision making. Professional magazines and informal discussions are considered the most esteemed information sources. Farmers' disposition to change, and co-operation, are also discussed, both of which are of vital importance for the development of new official administrative procedures.