The Student Volunteer Army: a ‘repeat emergent’ emergency response organisation

This paper seeks to contribute to understanding of the factors associated with an effective emergent emergency response organisation and to provide new insights into this understudied area. It examines, through an analysis of a range of textual resources, the emergence and re‐emergence of the Student Volunteer Army (SVA) during the devastating earthquakes in Canterbury, New Zealand, in 2010–11. This evaluation is conducted in relation to the four key features of an effective emergency response organisation: adaptability; direction; leadership; and communication. In addition, the paper aims to further understanding of ‘emergency entrepreneurship’ and thus of the values and strategies that underpin social entrepreneur organisations in times of normalcy. The paper concludes that the unique position of the SVA as a ‘repeat emergent’ emergency response organisation enabled it to innovate continually and to improve repeatedly its systems, relationships, and image, such that it exhibited features common to emergent and established emergency response organisations.     

Responses of herbaceous plants to urban air pollution: Effects on growth, phenology and leaf surface characteristics

Vehicle exhaust emissions are a dominant feature of urban environments and are widely believed to have detrimental effects on plants. The effects of diesel exhaust emissions on 12 herbaceous species were studied with respect to growth, flower development, leaf senescence and leaf surface wax characteristics. A diesel generator was used to produce concentrations of nitrogen oxides (NO_x) representative of urban conditions, in solardome chambers. Annual mean NO_x concentrations ranged from 77 nl l^−l to 98 nl l⁻¹, with NO:NO₂ ratios of 1.4-2.2, providing a good experimental simulation of polluted roadside environments. Pollutant exposure resulted in species-specific changes in growth and phenology, with a consistent trend for accelerated senescence and delayed flowering. Leaf surface characteristics were also affected; contact angle measurements indicated changes in surface wax structure following pollutant exposure. The study demonstrated clearly the potential for realistic levels of vehicle exhaust pollution to have direct adverse effects on urban vegetation.     

A one-dimensional model of vertical gas plume migration through a heterogeneous porous medium

This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding its atmospheric emissions and consequent global warming. Ideally, the injected greenhouse gas stays in the injection zone for a geologic time, eventually dissolves in the formation brine and remains trapped by mineralization. However, one of the potential problems associated with the geologic method of sequestration is that naturally present or inadvertently created conduits in the cap rock may result in a gas leakage from primary storage. Even in supercritical state, the carbon dioxide viscosity and density are lower than those of the formation brine. Buoyancy tends to drive the leaked CO₂plume upward. Theoretical and experimental studies of buoyancy-driven supercritical CO₂ flow, including estimation of time scales associated with plume evolution and migration, are critical for developing technology, monitoring policy, and regulations for safe carbon dioxide geologic sequestration.In this study, we obtain simple estimates of vertical plume propagation velocity taking into account the density and viscosity contrast between CO₂ and brine. We describe buoyancy-driven countercurrent flow of two immiscible phases by a Buckley–Leverett type model. The model predicts that a plume of supercritical carbon dioxide in a homogeneous water-saturated porous medium does not migrate upward like a bubble in bulk water. Rather, it spreads upward until it reaches a seal or until it becomes immobile. A simple formula requiring no complex numerical calculations describes the velocity of plume propagation. This solution is a simplification of a more comprehensive theory of countercurrent plume migration [Silin, D., Patzek, T.W., Benson, S.M., 2007. A Model of Buoyancy-driven Two-phase Countercurrent Fluid Flow. Laboratory Report LBNL-62607. Lawrence Berkeley National Laboratory, Berkeley, CA]. In a layered reservoir, the simplified solution predicts a slower plume front propagation relative to a homogeneous formation with the same harmonic mean permeability. In contrast, the model yields much higher plume propagation estimates in a high-permeability conduit like a vertical fracture.     

The role of optimality in characterizing CO2 seepage from geologic carbon sequestration sites

Storage of large amounts of carbon dioxide (CO₂) in deep geologic formations for greenhouse-gas mitigation is gaining momentum and moving from its conceptual and testing stages towards widespread application. In this work we explore various optimization strategies for characterizing surface leakage (seepage) using near-surface measurement approaches such as accumulation chambers and eddy covariance towers. Seepage characterization objectives and limitations need to be defined carefully from the outset especially in light of large natural background variations that can mask seepage. The cost and sensitivity of seepage detection are related to four critical length scales pertaining to the size of the: (1) region that needs to be monitored; (2) footprint of the measurement approach, and (3) main seepage zone; (4) region in which concentrations or fluxes are influenced by seepage. Seepage characterization objectives may include one or all of the tasks of detecting, locating, and quantifying seepage. Each of these tasks has its own optimal strategy. Detecting and locating seepage in a region in which there is no expected or preferred location for seepage nor existing evidence for seepage requires monitoring on a fixed grid, e.g., using eddy covariance towers. The fixed-grid approaches needed to detect seepage are expected to require large numbers of eddy covariance towers for large-scale geologic CO₂ storage. Once seepage has been detected and roughly located, seepage zones and features can be optimally pinpointed through a dynamic search strategy, e.g., employing accumulation chambers and/or soil-gas monitoring. Quantification of seepage rates can be done through measurements on a localized fixed grid once the seepage is pinpointed. Background measurements are essential for seepage detection in natural ecosystems. Artificial neural networks are considered as regression models useful for distinguishing natural system behavior from anomalous behavior suggestive of CO₂ seepage without need for detailed understanding of natural system processes. Because of the local extrema in CO₂ fluxes and concentrations in natural systems, simple steepest-descent algorithms are not effective and evolutionary computation algorithms are proposed as a paradigm for dynamic monitoring networks to pinpoint CO₂ seepage areas.     

Determination of cytotoxicity of nephrotoxins on murine and human kidney cell lines

The present study investigates renal inner medullary collecting duct (mIMCD3) cells and human embryonic kidney cells (HEK293) for evaluation of cytotoxicity of nephrotoxic compounds. The 24 h LC(50) values for cisplatin, paraquat and ibuprofen in mIMCD3 cells were 135, 155 and 3600 microM, respectively. The 24 h LC(50) values for paraquat and ibuprofen in HEK293 cells were 180 and 1000 microM, respectively. Effects of hyperosmolality on cytotoxicity of paraquat were additive in mIMCD3 cells. These data demonstrate that renal hyperosmolality has an additive effect on cytoxicity of paraquat.     

Climate Change and Water Resources in Arid Mountains: An Example from the Bolivian Andes

Climate change is projected to have a strongly negative effect on water supplies in the arid mountains of South America, significantly impacting millions of people. As one of the poorest countries in the region, Bolivia is particularly vulnerable to such changes due to its limited capacity to adapt. Water security is threatened further by glacial recession with Bolivian glaciers losing nearly half their ice mass over the past 50 years raising serious water management concerns. This review examines current trends in water availability and glacier melt in the Bolivian Andes, assesses the driving factors of reduced water availability and identifies key gaps in our knowledge of the Andean cryosphere. The lack of research regarding permafrost water sources in the Bolivian Andes is addressed, with focus on the potential contribution to mountain water supplies provided by rock glaciers.     

Antibiotic degradation during manure composting

On-farm manure management practices, such as composting, may provide a practical and economical option for reducing antibiotic concentrations in manure before land application, thereby minimizing the potential for environmental contamination. The objective of this study was to quantify degradation of chlortetracycline, monensin, sulfamethazine, and tylosin in spiked turkey (Meleagris gallopavo) litter during composting. Three manure composting treatments were evaluated: a control treatment (manure pile with no disturbance or adjustments after initial mixing), a managed compost pile (weekly mixing and moisture content adjustments), and vessel composting. Despite significant differences in temperature, mass, and nutrient losses between the composting treatments and the control, there was no difference in antibiotic degradation among the treatments. Chlortetracycline concentrations declined rapidly during composting, whereas monensin and tylosin concentrations declined gradually in all three treatments. There was no degradation of sulfamethazine in any of treatments. At the conclusion of the composting period (22-35 d), there was >99% reduction in chlortetracycline, whereas monensin and tylosin reduction ranged from 54 to 76% in all three treatments. Assuming first-order decay, the half-lives for chlortetracycline, monensin, and tylosin were 1, 17, and 19 d, respectively. These data suggest that managed compositing in a manure pile or in a vessel is not better than the control treatment in degrading certain antibiotics in manure. Therefore, low-level manure management, such as stockpiling, after an initial adjustment of water content may be a practical and economical option for livestock producers in reducing antibiotic levels in manure before land application.     

Greenhouse gas balance for composting operations

The greenhouse gas (GHG) impact of composting a range of potential feedstocks was evaluated through a review of the existing literature with a focus on methane (CH(4)) avoidance by composting and GHG emissions during composting. The primary carbon credits associated with composting are through CH(4) avoidance when feedstocks are composted instead of landfilled (municipal solid waste and biosolids) or lagooned (animal manures). Methane generation potential is given based on total volatile solids, expected volatile solids destruction, and CH(4) generation from lab and field incubations. For example, a facility that composts an equal mixture of manure, newsprint, and food waste could conserve the equivalent of 3.1 Mg CO(2) per 1 dry Mg of feedstocks composted if feedstocks were diverted from anaerobic storage lagoons and landfills with no gas collection mechanisms. The composting process is a source of GHG emissions from the use of electricity and fossil fuels and through GHG emissions during composting. Greenhouse gas emissions during composting are highest for high-nitrogen materials with high moisture contents. These debits are minimal in comparison to avoidance credits and can be further minimized through the use of higher carbon:nitrogen feedstock mixtures and lower-moisture-content mixtures. Compost end use has the potential to generate carbon credits through avoidance and sequestration of carbon; however, these are highly project specific and need to be quantified on an individual project basis.     

Guiding principles for rewilding

There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding.