On the unipolarity of charge transport in methanofullerene diodes

Fullerenes are electron transporting organic semiconductors with a wide range of applications. In particular, methanofullereneshave been the preferred choice for solution-processed solar cells and photodiodes. The wide applicability of fullerenes as both ‘ntype’transport materials and electron acceptors is clear. However, what is still a matter of debate is whether the fullerenes can alsosupport efficient transport of holes, particularly in diode geometries. In this letter, we utilize a number of recently developedexperimental methods for selective electron and hole mobility measurements. We show for the two most widely used solutionprocessable fullerenes, PC70- and-PC60BM, that whilst both exhibit electron mobilities as high as 10−3 cm2/Vs, their hole mobilities

Environmental noise reduces predation rate in an aquatic invertebrate

Noise is one of a wide range of disturbances associated with human activities that have been shown to have detrimental impacts on a wide range of species, from montane regions to the deep marine environment. Noise may also have community-level impacts via predator–prey interactions, thus jeopardising the stability of trophic networks. However, the impact of noise on freshwater ecosystems is largely unknown. Even more so is the case of insects, despite their crucial role in trophic networks. Here, we study the impact of underwater noise on the predatory functional response of damselfly larvae. We compared the feeding rates of larvae under anthropogenic noise, natural noise, and silent conditions. Our results suggest that underwater noise (pooling the effects of anthropogenic noise and natural noise) decreases the feeding rate of damselflies significantly compared to relatively silent conditions. In particular, natural noise increased the handling time significantly compared to the silent treatment, thus reducing the feeding rate. Unexpectedly, feeding rates under anthropogenic noise were not reduced significantly compared to silent conditions. This study suggests that noise per se may not necessarily have negative impacts on trophic interactions. Instead, the impact of noise on feeding rates may be explained by the presence of nonlinearities in acoustic signals, which may be more abundant in natural compared to anthropogenic noise. We conclude by highlighting the importance of studying a diversity of types of acoustic pollution, and encourage further work regarding trophic interactions with insects using a functional response approach

Lentivirus-meditated frataxin gene delivery reverses genome instability in Friedreich ataxia patient and mouse model fibroblasts

Friedreich ataxia (FRDA) is a progressive neurodegenerative disease caused by deficiency of frataxin protein, with the primary sites of pathology being the large sensory neurons of the dorsal root ganglia and the cerebellum. FRDA is also often accompanied by severe cardiomyopathy and diabetes mellitus. Frataxin is important in mitochondrial iron–sulfur cluster (ISC) biogenesis and low-frataxin expression is due to a GAA repeat expansion in intron 1 of the FXN gene. FRDA cells are genomically unstable, with increased levels of reactive oxygen species and sensitivity to oxidative stress. Here we report the identification of elevated levels of DNA double strand breaks (DSBs) in FRDA patient and YG8sR FRDA mouse model fibroblasts compared to normal fibroblasts. Using lentivirus FXN gene delivery to FRDA patient and YG8sR cells, we obtained long-term overexpression of FXN mRNA and frataxin protein levels with reduced DSB levels towards normal. Furthermore, γ-irradiation of FRDA patient and YG8sR cells revealed impaired DSB repair that was recovered on FXN gene transfer. This suggests that frataxin may be involved in DSB repair, either directly by an unknown mechanism, or indirectly via ISC biogenesis for DNA repair enzymes, which may be essential for the prevention of neurodegeneration.Ataxia UK, FARA Australasia and FARA US

Can climate policy enhance sustainability?

Implementing an effective climate policy is one of the main challenges for the future. Curbing greenhouse gas emissions can prevent future irreversible impacts of climate change. Climate policy is therefore crucial for present and future generations. Nonetheless, one may wonder whether future economic and social development could be harmed by climate policy. This paper addresses this question by examining recent developments in international climate policy and considering different levels of cooperation that may arise in light of the outcomes of the Conference of the Parties held in Doha. The paper analyses how various climate policy scenarios would enhance sustainability and whether there is a trade-off between climate policy and economic development and social cohesion. This is done by using a new comprehensive indicator, the FEEM Sustainability Index (FEEM SI), which aggregates several economic, social, and environmental indicators. The FEEM SI is built into a recursive-dynamic computable general equilibrium model of the world economy, thus offering the possibility of projecting all indicators into the future and of delivering a perspective assessment of sustainability under different future climate policy scenarios. We find that the environmental component of sustainability improves at the regional and world level thanks to the implementation of climate policies. Overall sustainability increases in all scenarios since the economic and social components are affected negatively yet marginally. This analysis does not include explicitly climate change damages and this may lead to underestimating the benefits of policy actions. If the USA, Canada, Japan and Russia did not contribute to mitigating emissions, sustainability in these countries would decrease and the overall effectiveness of climate policy in enhancing global sustainability would be offset

Comparing the Invasibility of Experimental “Reefs” with Field Observations of Natural Reefs and Artificial Structures

Natural systems are increasingly being modified by the addition of artificial habitats which may facilitate invasion. Where invaders are able to disperse from artificial habitats, their impact may spread to surrounding natural communities and therefore it is important to investigate potential factors that reduce or enhance invasibility. We surveyed the distribution of non-indigenous and native invertebrates and algae between artificial habitats and natural reefs in a marine subtidal system. We also deployed sandstone plates as experimental ‘reefs’ and manipulated the orientation, starting assemblage and degree of shading. Invertebrates (non-indigenous and native) appeared to be responding to similar environmental factors (e.g. orientation) and occupied most space on artificial structures and to a lesser extent reef walls. Non-indigenous invertebrates are less successful than native invertebrates on horizontal reefs despite functional similarities. Manipulative experiments revealed that even when non-indigenous invertebrates invade vertical “reefs”, they are unlikely to gain a foothold and never exceed covers of native invertebrates (regardless of space availability). Community ecology suggests that invertebrates will dominate reef walls and algae horizontal reefs due to functional differences, however our surveys revealed that native algae dominate both vertical and horizontal reefs in shallow estuarine systems. Few non-indigenous algae were sampled in the study, however where invasive algal species are present in a system, they may present a threat to reef communities. Our findings suggest that non-indigenous species are less successful at occupying space on reef compared to artificial structures, and manipulations of biotic and abiotic conditions (primarily orientation and to a lesser extent biotic resistance) on experimental “reefs” explained a large portion of this variation, however they could not fully explain the magnitude of differences

Sodium Chloride Inhibits the Growth and Infective Capacity of the Amphibian Chytrid Fungus and Increases Host Survival Rates

The amphibian chytrid fungus Batrachochytrium dendrobatidis is a recently emerged pathogen that causes the infectious disease chytridiomycosis and has been implicated as a contributing factor in the global amphibian decline. Since its discovery, research has been focused on developing various methods of mitigating the impact of chytridiomycosis on amphibian hosts but little attention has been given to the role of antifungal agents that could be added to the host's environment. Sodium chloride is a known antifungal agent used routinely in the aquaculture industry and this study investigates its potential for use as a disease management tool in amphibian conservation. The effect of 0–5 ppt NaCl on the growth, motility and survival of the chytrid fungus when grown in culture media and its effect on the growth, infection load and survivorship of infected Peron's tree frogs (Litoria peronii) in captivity, was investigated. The results reveal that these concentrations do not negatively affect the survival of the host or the pathogen. However, concentrations greater than 3 ppt significantly reduced the growth and motility of the chytrid fungus compared to 0 ppt. Concentrations of 1–4 ppt NaCl were also associated with significantly lower host infection loads while infected hosts exposed to 3 and 4 ppt NaCl were found to have significantly higher survival rates. These results support the potential for NaCl to be used as an environmentally distributed antifungal agent for the prevention of chytridiomycosis in susceptible amphibian hosts. However, further research is required to identify any negative effects of salt exposure on both target and non-target organisms prior to implementation

In search of income reference points for SLCA using a country level sustainability benchmark (part 1): fair inequality. A contribution to the Oiconomy project

Purpose: This paper is part 1 of our twin articles on income reference points for Social Life Cycle Assessment (SLCA). Preventative costs based LCA systems, such as the EcoCost system and the Oiconomy system, need targets (performance reference points) to determine the marginal preventative costs, the costs of the most expensive measure that globally needs to be employed to reach the target. To extend the EcoCost system for social issues, targets are required for issues like fair wages and fair inequality of wages, issues for which no agreed standard, no effect level or target exists. One way of setting targets is to take best practices as benchmark, e.g. the practices of a group of best performing countries. The purpose of this part 1 article is to first develop a well-founded benchmark group of the 20 % best performing countries and thereafter propose a well-founded target for the issue of inequality for preventative costs based SLCA, which can also serve as performance reference point for SLCA in general and for other uses. In part 2, for the same purposes and using the same benchmark group, we propose targets for fair minimum wages for every country. Methods: A benchmark group of countries for the setting of targets was determined by an assessment of available country performance indicators, based on 5 criteria. Thereafter, we derived a proposal for a maximum inequality ratio based on existing democratically determined inequality ratios in the benchmark group. Results and discussion: The Sustainable Society Index–Human Wellbeing proved the best indicator for a country benchmark for preventative cost-based SLCA. Using the average of maximum democratically determined income differences in a benchmark group of countries determined by this index, a performance reference point for SLCA for the issue of fair inequality was derived and proposed, resulting in a maximum ratio of income differences for governmental institutions of 14.1, for government ruled companies of 18.3 and for industry of a factor 23.8. Conclusions: It proved possible to derive a target for maximum inequality of wages, based on democratic choices in a benchmark group of the 20 % best performing countries. The target for governmental institutions may be called objective, and proposed augmentations for government ruled companies and industry, though value choices, seem reasonable for the consumer who requires prevention of all possible harm as consequence of his purchase choices and who, as a voter, contributes to governmental standards