Efficient electrocatalytic water oxidation at neutral and high pH by adventitious nickel at nanomolar concentrations

Electrolytic water oxidation using earth-abundant elements is a key challenge in the quest to develop cheap, large surface area arrays for solar-to-hydrogen conversion. There have been numerous studies in this area in recent years, but there remains an imperative to demonstrate that the current densities reported are indeed due to the species under consideration and not due to the presence of adventitious (yet possibly highly active) contaminants at low levels. Herein, we show that adventitious nickel at concentrations as low as 17 nM can act as a water oxidation catalyst in mildly basic aqueous solutions, achieving stable (tens of hours) current densities of 1 mA cm–2 at overpotentials as low as 540 mV at pH 9.2 and 400 mV at pH 13. This nickel was not added to the electrolysis baths deliberately, but it was found to be present in the electrolytes as an impurity by ICP-MS. The presence of nickel on anodes from extended-time bulk electrolysis experiments was confirmed by XPS. In showing that such low levels of nickel can perform water oxidation at overpotentials comparable to many recently reported water oxidation catalysts, this work serves to raise the burden of proof required of new materials in this field: contamination by adventitious metal ions at trace loadings must be excluded as a possible cause of any observed water oxidation activity

Testing a recipe for effective recovery plan design: a marine turtle case study

Managing impacts to threatened species is challenging, because it is intrinsically linked to resources, knowledge, capacity and public and government will. A key tool often used in species conservation is a recovery or management plan. Yet all too often, plans are not designed for evaluation and not tested against quantitative criteria. Our study takes a novel approach to recovery plan assessment by assembling a worldwide database of recovery plans for a single taxon. We obtained 79 recovery or management plans for marine turtles and then designed criteria to assess and compare them for their ability to be evaluated and thus successfully implemented. We then used expert opinion of marine turtle specialists to weigh our 18 criteria. Overall, we found that the failure to adequately integrate adaptive management into plan design was a major shortcoming of marine turtle recovery planning (>90% of plans). Other common gaps included inadequacy of measurable objectives (75% of plans) and an absence of timelines (50% of plans). We highlight knowledge gaps relating to status trends, critical habitat and a lack of incorporation of social aspects such as stewardship and education. Our research underlines the importance of recovery planning from multiple scales and provides a step towards designing recovery plans that include SMART (specific, measurable, achievable, realistic and time-bound) objectives; scientific information; social aspects; and evaluation. We highlight the importance of national and multi-national planning processes to produce internationally relevant plans that will maximise conservation efforts for a globally threatened marine species

New One-Pot Methodologies for the Modification or Synthesis of Alkaloid Scaffolds

There are several avenues by which promising bioactive natural products can be produced in sufficient quantities to enable lead optimization and medicinal chemistry studies. The total synthesis of natural products is an important, but sometimes difficult, approach and requires the development of innovative synthetic methodologies to simplify the synthesis of complex molecules. Various classes of natural product alkaloids are both common and widely distributed in plants, bacteria, fungi, insects and marine organisms. This mini-review will discuss the scope, mechanistic insights and enantioselectivity aspects of selected examples of recently developed one-pot methods that have been published in 2009 for the synthesis of substituted piperidines, quinolizidines, pyrrolidines, hexahydropyrrolizines, octahydroindolizines and γ-lactams. In addition, progress on the synthesis of β-carboline (manzamine) alkaloids will also be discussed

CFD Simulation of Liquid-Liquid Extraction Columns and Visualization of Eulerian Datasets

In this joint work, a complete framework for modeling, simulating and visualizing multiphase fluid flow within an extraction column is presented. We first present a volume-of-fluid simulation, which is able to predict the surface of the droplets during coalescence. However, a fast and efficient model is needed for the simulation of a liquid-liquid extraction column due to the high number of occurring droplets. To simulate the velocity and droplet size in a DN32 extraction column, a coupled computational fluid dynamic-population balance model solver is used. The simulation is analyzed using path-line based visualization techniques. A novel semi-automatic re-seeding technique for droplet path-line integration is proposed. With our technique, path-lines of fluid droplets can be re-initialized after contact with the stirring devices. The droplet breakage is captured, allowing the engineer to improve the design of liquid-liquid columns layout

CFD Simulation of Liquid-Liquid Extraction Columns and Visualization of Eulerian Datasets

In this joint work, a complete framework for modeling, simulating and visualizing multiphase fluid flow within an extraction column is presented. We first present a volume-of-fluid simulation, which is able to predict the surface of the droplets during coalescence. However, a fast and efficient model is needed for the simulation of a liquid-liquid extraction column due to the high number of occurring droplets. To simulate the velocity and droplet size in a DN32 extraction column, a coupled computational fluid dynamic-population balance model solver is used. The simulation is analyzed using path-line based visualization techniques. A novel semi-automatic re-seeding technique for droplet path-line integration is proposed. With our technique, path-lines of fluid droplets can be re-initialized after contact with the stirring devices. The droplet breakage is captured, allowing the engineer to improve the design of liquid-liquid columns layout

Using habitat suitability models in an industrial setting: the case for internesting flatback turtles

To predict and manage ecological impacts of anthropogenic activities effectively, an understanding of at-risk species spatial ecology is first required. This is particularly difficult in the marine environment due to limited offshore access and wide-ranging movements of some species. Flatback turtles are a protected species potentially at risk from hazards associated with the resource sector in Australia, yet their at-sea spatial ecology is not well understood. We use habitat suitability modeling to identify environmental variables that influence flatback turtle internesting movement; identify areas of suitable internesting habitat; and determine overlap of identified internesting habitat with resource sector hazards. Internesting movements of 47 female flatback turtles, from five rookeries in the North West Shelf region of Western Australia, were recorded using platform terminal transmitters between 2006 and 2010. Environmental variables including sea surface temperature (SST), bathymetry, magnetic anomalies, distance from coastline, slope, and ruggedness index were combined with the tracking data from each rookery in an ecological niche model. We used the positions of resource sector vessels to represent areas of potential impact from resource sector hazards and identified overlap with suitable internesting habitat areas as a representative of the likelihood of impact. The primary environmental variables that influenced flatback internesting movement were bathymetry, distance from coastline, and SST. Suitable areas of internesting habitat were located in close proximity to many known flatback turtle rookeries across the region. Areas of suitable internesting habitat overlapped resource sector hazards in close proximity to four of the five rookeries and at other known flatback turtle rookeries. The cumulative overlap across the overall study area indicates a high potential for interaction with resource sector hazards, demonstrating the need for regional protection measures in these areas. This study provides a capability for regulators and developers to determine the potential offshore presence of internesting flatback turtles within the region, allowing for protection measures to be targeted appropriately as industrial development continues

Bioaccumulation and biomagnification of microplastics in marine organisms: a review and meta-analysis of current data

Microplastic (MP) contamination has been well documented across a range of habitats and for a large number of organisms in the marine environment. Consequently, bioaccumulation, and in particular biomagnification of MPs and associated chemical additives, are often inferred to occur in marine food webs. Presented here are the results of a systematic literature review to examine whether current, published findings support the premise that MPs and associated chemical additives bioaccumulate and biomagnify across a general marine food web. First, field and laboratory-derived contamination data on marine species were standardised by sample size from a total of 116 publications. Second, following assignment of each species to one of five main trophic levels, the average uptake of MPs and of associated chemical additives was estimated across all species within each level. These uptake data within and across the five trophic levels were then critically examined for any evidence of bioaccumulation and biomagnification. Findings corroborate previous studies that MP bioaccumulation occurs within each trophic level, while current evidence around bioaccumulation of associated chemical additives is much more ambiguous. In contrast, MP biomagnification across a general marine food web is not supported by current field observations, while results from the few laboratory studies supporting trophic transfer are hampered by using unrealistic exposure conditions. Further, a lack of both field and laboratory data precludes an examination of potential trophic transfer and biomagnification of chemical additives associated with MPs. Combined, these findings indicate that, although bioaccumulation of MPs occurs within trophic levels, no clear sign of MP biomagnification in situ was observed at the higher trophic levels. Recommendations for future studies to focus on investigating ingestion, retention and depuration rates for MPs and chemical additives under environmentally realistic conditions, and on examining the potential of multi-level trophic transfer for MPs and chemical additives have been made

The High School in the Middle of Everywhere: Nebraska’s Lincoln High

In 2002, world-renowned author Mary Pipher published a book about her home city, Lincoln Nebraska, playfully titled “The Middle of Everywhere” a tongue-in-cheek rejoinder to the idea that Nebraska is ‘the middle of nowhere.’ But word play aside, her title was empirically apt, as her volume documented how immigration and refugee resettlement were demographically transforming Nebraska’s capital city. As in other cities, resettlement was concentrated in some areas of Lincoln, placing differential burdens on different parts of the community’s institutional infrastructure. Of interest to readers of this volume, Lincoln’s refugees and immigrants were concentrated in the city’s oldest high school. This account shares how that school embraced the challenges of demographic change by valuing the knowledge, skills and experience of students and their families

Stakeholder engagement in the governance of marine migratory species: barriers and building blocks

Meaningful stakeholder engagement is important to collaborative decision-making and to effective polycentric governance, particularly when managing cross-scale environmental issues like those involving marine migratory species. In this paper, we explore the barriers to, and opportunities for, stakeholder involvement in the governance of threats to marine migratory species in eastern Australia, using semi-structured qualitative interviews and a focus group, as an example of the generic problem of managing migratory species within a large range state with multiple jurisdictions. Respondents identified several barriers to, and opportunities for, improved stakeholder involvement in the governance of marine migratory species, corresponding to 4 main themes: decision-making processes, information sharing, institutional structures, and participation processes. Respondents indicated that the governance system protecting marine turtles, dugongs, humpback whales, and non-threatened migratory shorebirds in eastern Australia would benefit from the introduction of new information pathways, reformed institutional structures (including environmental legislation), and improved participatory pathways for non-government stakeholders. Such changes could help harmonise the process of managing these species, leading to more effective conservation management throughout their range

Multiresolution Techniques for Interactive Texture-Based Rendering of Arbitrarily Oriented Cutting Planes

We present a multiresolution technique for interactive texture based rendering of arbitrarily oriented cutting planes for very large data sets. This method uses an adaptive scheme that renders the data along a cutting plane at different resolutions: higher resolution near the point-of-interest and lower resolution away from the point-of-interest. The algorithm is based on the segmentation of texture space into an octree, where the leaves of the tree define the original data and the internal nodes define lower-resolution versions. Rendering is done adaptively by selecting high-resolution versions. Rendering is done adaptively by selecting high-resolution cells close to a center of attention and low-resolution cells away from it. We limit the artifacts introduced by this method by blending between different levels of resolution to produce a smooth image. This techinique can be used to produce a viewpoint-dependent renderings