364 research outputs found
The artificial leaf: An investigation into the sociotechnical integration of new solar energy innovations
Increasing global demand, combined with the volatility of fossil fuels, has called for a large-scale increase in renewable energy production. Photovoltaics hold significant potential, but by nature, solar energy is intermittent and lacks dispatchability. Researchers around the world are working to create innovative solutions that utilize semiconductors found in solar cell technologies in new ways. This project harnesses photoelectrochemical water-splitting, which uses light energy to dissociate water molecules into hydrogen and oxygen. When the water-splitting device is submerged in saltwater and illuminated by sunlight, oxygen and hydrogen gas are produced on opposite surfaces, and can be either released or stored for later use. This device imitates the light-driven catalysts found in the chloroplasts of photosynthesizing plants, which is why it is so aptly named the artificial leaf. Stored hydrogen can be burned in a fuel cell, producing electricity with a byproduct of pure water and no greenhouse gas emissions. In the lab, two strategies to improve artificial leaves were investigated: (1) introducing a transparent, electrically-conducting scaffold made from textured SnO2:Sb to support the BiVO4 photocatalyst, and (2) applying a thin FeOOH co-catalyst coating to the BiVO4 surface to enhance the efficiency of the water-splitting process.
While this product has not yet achieved optimum efficiency, experimental efforts are continuing to improve the performance of JMU artificial leaf prototypes. Once fully integrated into society, hydrogen produced from artificial leaves can be burned in small fuel cells within hydrogen-powered vehicles, while large-scale fuel cells can be used to provide both electricity and fresh water to island and coastal communities. Studying the artificial leaf as an emerging technology allows researchers to identify sociotechnical considerations through scenario crosses, the STIR protocol, systems dynamics modeling, and comparative analyses. Insights collected from experts in the field will inform project characteristics as design fictions are implemented. Existing policies, cultural views, stakeholder analyses, ethical key questions, local job/revenue creation, and the co-production of technology and society are each thoroughly explored to hypothesize how artificial leaves will be integrated into coastal communities
Dispersal capacity predicts both population genetic structure and species richness in reef fishes
Dispersal is a fundamental species characteristic that should directly affect both rates of gene flow among spatially distributed populations and opportunities for speciation. Yet no single trait associated with dispersal has been demonstrated to affect both micro- and macroevolutionary patterns of diversity across a diverse biological assemblage. Here, we examine patterns of genetic differentiation and species richness in reef fishes, an assemblage of over 7,000 species comprising approximately one-third of the extant bony fishes and over one-tenth of living vertebrates. In reef fishes, dispersal occurs primarily during a planktonic larval stage. There are two major reproductive and parental investment syndromes among reef fishes, and the differences between them have implications for dispersal: (1) benthic guarding fishes lay negatively buoyant eggs, typically guarded by the male parent, and from these eggs hatch large, strongly swimming larvae; in contrast, (2) pelagic spawning fishes release small floating eggs directly into the water column, which drift unprotected before small weakly swimming larvae hatch. Using phylogenetic comparative methods, we show that benthic guarders have significantly greater population structure than pelagic spawners and additionally that taxonomic families of benthic guarders are more species rich than families of pelagic spawners. Our findings provide a compelling case for the continuity between micro- and macroevolutionary processes of biological diversification and underscore the importance of dispersalrelated traits in influencing the mode and tempo of evolution
Operationalizing ecological connectivity in spatial conservation planning with Marxan Connect
1. Globally, protected areas are being established to protect biodiversity and to promote ecosystem resilience. The typical spatial conservation planning process leading to the creation of these protected areas focuses on representation and replication of ecological features, often using decision support tools such as Marxan. Yet, despite the important role ecological connectivity has in metapopulation persistence and resilience, Marxan currently requires manual input or specialized scripts to explicitly consider connectivity.
2. ‘Marxan Connect’ is a new open source, open access Graphical User Interface (GUI) tool designed to assist conservation planners with the appropriate use of data on ecological connectivity in protected area network planning.
3. Marxan Connect can facilitate the use of estimates of demographic connectivity (e.g. derived from animal tracking data, dispersal models, or genetic tools) or structural landscape connectivity (e.g. isolation by resistance). This is accomplished by calculating metapopulation‐relevant connectivity metrics (e.g. eigenvector centrality) and treating those as conservation features or by including the connectivity data as a spatial dependency amongst sites in the prioritization process.
4. Marxan Connect allows a wide group of users to incorporate directional ecological connectivity into conservation planning with Marxan. The solutions provided by Marxan Connect, combined with ecologically relevant post‐hoc testing, are more likely to support persistent and resilient metapopulations (e.g. fish stocks) and provide better protection for biodiversity
Geographic information systems in epidemiology – ecology of common vole and distribution of natural foci of tularaemia
KORMAP geographic information system (GIS) was used to analyse the distribution and selected environmental factors related to population levels of Microtus arvalis (a potential reservoir host of F. tularensis) in the Czech Republic and the relation between M. arvalis populations and natural foci of tularaemia in the European hare. Maximum population levels of M. arvalis were in areas from 200 to 399 m above sea, of 40 to 60 days of snow cover annually and of 10 °C of mean annual air temperature. Warm and moderately warm climatic regions differed in the mean M. arvalis population level with high statistical significance (t = 4.97, P = 0.01). M. arvalis did not occur in the cold climatic region and areas of less than 4 °C of mean annual air temperature. The highest and lowest population densities were found in geographic areas of 1800 to 2000 h and up to 1600 h of annual sunshine duration, respectively. M. arvalis population density correlates with high statistical significance with the elevation above sea, annual sunshine duration and mean annual air temperature. It was, however, found that there is no correlation between M. arvalis levels and numbers of natural foci of tularaemia in the European hare (r = 0.0765, n = 396, t = 1.5228). In other words, tularaemia seems to be independent of M. arvalis population density. GIS are suitable for the State Veterinary Administration and they are becoming part of decision-making as knowledge on the geographical aspects of diseases including the distribution of reservoir hosts is essential for disease control. Microtus arvalis, geography of occurrence, population levels, environmental factors, Czech Republic, tularaemi
The DNA of coral reef biodiversity: predicting and protecting genetic diversity of reef assemblages
Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover harbour the greatest genetic diversity on average. We found that a species’s life history (e.g. depth range and herbivory) mediates response of genetic diversity to seascape drivers in logical ways. Furthermore, a metric of combined multi-species AR showed strong coupling to species richness and habitat area, quality and stability that few species showed individually. We hypothesize that macro-ecological forces and species interactions, by mediating species turnover and occupancy (and thus a site’s mean effective population size), influence the aggregate genetic diversity of a site, potentially allowing it to behave as an apparent emergent trait that is shaped by the dominant seascape drivers. The results highlight inherent feedbacks between ecology and genetics, raise concern that genetic resilience of entire reef communities is compromised by factors that reduce coral cover or available habitat, including thermal stress, and provide a foundation for new strategies for monitoring and preserving biodiversity of entire reef ecosystems
Geographic Information Systems in Epidemiology – Ecology of Common Vole and Distribution of Natural Foci of Tularaemia
KORMAP geographic information system (GIS) was used to analyse the distribution and selected environmental factors related to population levels of Microtus arvalis (a potential reservoir host of F. tularensis) in the Czech Republic and the relation between M. arvalis populations and natural foci of tularaemia in the European hare. Maximum population levels of M. arvalis were in areas from 200 to 399 m above sea, of 40 to 60 days of snow cover annually and of 10 °C of mean annual air temperature. Warm and moderately warm climatic regions differed in the mean M. arvalis population level with high statistical significance (t = 4.97, P = 0.01). M. arvalis did not occur in the cold climatic region and areas of less than 4 °C of mean annual air temperature. The highest and lowest population densities were found in geographic areas of 1800 to 2000 h and up to 1600 h of annual sunshine duration, respectively. M. arvalis population density correlates with high statistical significance with the elevation above sea, annual sunshine duration and mean annual air temperature. It was, however, found that there is no correlation between M. arvalis levels and numbers of natural foci of tularaemia in the European hare (r = 0.0765, n = 396, t = 1.5228). In other words, tularaemia seems to be independent of M. arvalis population density. GIS are suitable for the State Veterinary Administration and they are becoming part of decision-making as knowledge on the geographical aspects of diseases including the distribution of reservoir hosts is essential for disease control. Microtus arvalis, geography of occurrence, population levels, environmental factors, Czech Republic, tularaemi
Primer development for detection of Phaseolus vulgaris and Olathe transgenic bean.
Several strategies have been employed for genetically engineering resistance to viruses in transgenic plants. The bean golden mosaic virus (BGMV) is responsible for causing the gold mosaic of common bean (Phaseolus vulgaris L.) and causes severe yield losses due to yellow-green mosaic of leaves, stunted growth and distorted pods. Olathe transgenic bean (Olathe 5.1) was successfully produced by EMBRAPA using the RNA interference (RNAi) concept to silence the rep viral gene in common bean to generate transgenic lines with strong resistance to BGMV. In this work, real time PCR (RT-PCR) method with SYBR Green was developed to detect this newly genetically modified (GM) plant
New plasmid calibrators for geminivirus-resistant (EMB-PV051-1 event) common bean (Phaseolus vulgaris L.) quantitation using simplex and duplex qPCR.
The geminivirus-resistant common bean, Embrapa 5.1, was the first commercial genetically modified (GM) event developed in Latin America by the Brazilian Agricultural Research Corp.. Therein novel standard reference plasmids were constructed for species-specific (pLEC) and event-specific (pFGM) qualitative and quantitative detection of Embrapa 5.1 GM common bean. To establish these plasmids as certified reference materials (CRM) for Embrapa 5.1 GM common bean, two DNA extraction protocols, simplex and duplex qPCR using two different operators (experimenters) were tested. The efficiency values ranged from 92% to 110% for the simplex and duplex reactions considering both operators. The limit of detection was enough to detect at least 0.1% GM content. These plasmids are suitable to be used as CRM for Embrapa 5.1 GM common bean. They will be useful for survey of food labels for compliance with legislation about GMO content in Brazil and in other countries where GM common bean is not yet approved for commercialization
No First-Order Phase Transition in the Gross-Neveu Model?
Within a variational calculation we investigate the role of baryons for the
structure of dense matter in the Gross-Neveu model. We construct a trial ground
state at finite baryon density which breaks translational invariance. Its
scalar potential interpolates between widely spaced kinks and antikinks at low
density and the value zero at infinite density. Its energy is lower than the
one of the standard Fermi gas at all densities considered. This suggests that
the discrete gamma_5 symmetry of the Gross-Neveu model does not get restored in
a first order phase transition at finite density, at variance with common
wisdom.Comment: 16 pages, 7 figures, LaTe
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