Strategic importance of green water in international crop trade

Virtual water is the volume of water used to produce a commodity or service. By importing agricultural commodities and the virtual water embedded in them, a country saves the water it would have required to produce those commodities domestically. Virtual-water ‘trade’, thus, has the potential to relieve water stress and improve water security. The present research critically evaluates the strategic importance and implications of green water (soil water) in relation to international crop trade. Even if, traditionally, emphasis has been given to irrigation systems, today most global crop production is rain-fed. Besides having a lower opportunity cost, green water use for the production of crops is considered more sustainable than the use of blue water (irrigation). Although green water represents the largest share of virtual water in the international trade of agricultural commodities, with exports going from highly productive rain-fed rich countries towards generally blue water based ones, green water volumes have rarely been estimated. The present study corroborates that green water is by far the largest share of virtual water embodied in maize, soybean and wheat exports from the USA, Canada, Australia and Argentina during the period 2000-2004. Accordingly, green virtual-water flows can play a major role in ensuring water security and saving water in water-deficit economies. The potential of international green virtual-water ‘trade’ for saving water and improving water security, however, is constrained by factors such as technology, the potential for further increases in the productivity, the level of socio-economic development, national food policies and international trade agreements

Diagnostic accuracy of leptospirosis whole-cell lateral flow assays: a systematic review and meta-analysis

Background: Leptospirosis is under-diagnosed by clinicians in many high-incidence countries, because reference diagnostic tests are largely unavailable. Lateral flow assays (LFA) that use antigen derived from heat-treated whole cell Leptospira biflexa serovar Patoc have the potential to improve leptospirosis diagnosis in resource-limited settings. Objectives: We sought to summarize estimates of sensitivity and specificity of LFA by conducting a systematic review and meta-analysis of evaluations of the accuracy of LFA to diagnose human leptospirosis. Data sources: On 4 July 2017 we searched three medical databases. Study eligibility criteria: Articles were included if they were a study of LFA sensitivity and specificity. Participants: Patients with suspected leptospirosis. Interventions: Nil. Methods: For included articles, we assessed study quality, characteristics of participants and diagnostic testing methods. We estimated sensitivity and specificity for each study against the study-defined case definition as the reference standard, and performed a meta-analysis using a random-effects bivariate model. Results: Our search identified 225 unique reports, of which we included nine (4%) published reports containing 11 studies. We classified one (9%) study as high quality. Nine (82%) studies used reference tests with considerable risk of misclassification. Our pooled estimates of sensitivity and specificity were 79% (95% CI 70%–86%) and 92% (95% CI 85%–96%), respectively. Conclusions: As the evidence base for determining the accuracy of LFA is small and at risk of bias, pooled estimates of sensitivity and specificity should be interpreted with caution. Further studies should use either reference tests with high sensitivity and specificity or statistical techniques that account for an imperfect reference standard

A novel niobium (oxy)nitride-BaCe0.7Zr0.1Y0.2O3-δ composite electrode for Proton Ceramic Membrane Reactors (PCMRs)

The necessity to accelerate green and low carbon technologies, to mitigate the pending energetic crisis, potentiates the urgent search for alternative energy transfer methods. In this regard, Proton Ceramic Membrane Reactors (PCMRs) have shown great potential as a clean alternative for both energy production and the electrochemical synthesis of a wide range of chemical products. One of the most important is that of ammonia, where recent literature has demonstrated the potential use of PCMRs to either synthesize this chemical product or to use it as a fuel, and where suitable new electrodes must be developed. Hence, this work investigates the use of niobium (oxy)nitride (NbNxOy) in combination with proton ceramic conducting materials, as a new category of composite electrode for PCMRs applications. To achieve this goal, firstly, the chemical compatibility of the NbNxOy phase with the well-known proton conducting perovskite, yttrium-doped barium cerate (BaCe0.9Y0.1O3-δ, BCY10), was assessed. By X-ray powder diffraction, BaCe0.7Zr0.1Y0.2O3-δ (BCZY712) was shown to be chemically stable with the NbNxOy phase, surviving up to 850 °C, thus, facilitating the production of an electrolyte supported composite electrode film based on BCZY712-NbNxOy (40–60 vol%). Thermogravimetric experiments combined with X-ray diffraction were also made to assess the thermal stability of the NbNxOy material in both N2 and 2 % H2/N2 atmospheres, revealing that NbNxOy decomposes into its parent oxide in N2, while retaining the pure (oxy)nitride phase in the more reducing conditions. The polarization behavior of the BCZY712-NbNxOy composite electrode was evaluated by electrochemical impedance spectroscopy under different gaseous conditions of H2/N2 and NH3 atmospheres. The overall electrode mechanism was tentatively explained by three main steps, including i) proton incorporation/water release or adsorption/desorption of water, ii) gaseous hydrogen adsorption/desorption, and iii) interfacial transfer reaction of either protons or oxygen-ion vacancies. To the best of our knowledge, this is the first work that reports a detailed chemical compatibility study of niobium (oxy)nitride with a protonic ceramic matrix, while also outlining a detailed electrode mechanism under prospective conditions of hydrogenation/de‑hydrogenation of ammonia.publishe

Greenhouse gas emissions of food waste disposal options for UK retailers

Food retailers are under increasing political and social pressure to reduce both the amount of food that they waste and the amount of greenhouse gases (GHGs) that their food retailing activities incur. For completeness, when assessing the ‘carbon footprint” of their business activities, food retailers should also included the greenhouse gas emissions caused by their disposal of waste food, which will vary with the waste disposal option used. However, there is lack of quantitative guidance for food retailers on the net GHG emissions that are incurred in the disposal of specific food types by the various disposal options available. Here, we calculate the net GHG emissions of eight different waste disposal options for five core food types using life cycle assessment, accounting for both emissions incurred in transport and processing, and those mitigated by the creation of useful products. We also assess the extent to which the embodied emissions in waste foods at the retail checkout can be mitigated by each disposal option. In addition to food specific results, we calculate mass-weighted averages using data from a mid-sized retail chain. We find a strong correlation between net emissions and the energy density of foods, and the following mass weighted disposal hierarchy (from best to worst, with respect to greenhouse gas emissions): donation of edible food to food banks; anaerobic digestion; conversion to animal feed; incineration with energy recovery; aerobic composting; landfill with gas collection and utilisation; landfill with gas collection and flaring; landfill without gas collection. If waste food from retailers is unfit for human consumption, to minimise greenhouse gas emissions it should be disposed of by conversion to animal feed or anaerobic digestion. For all food types, landfill is the worst disposal option

Adventures in boron chemistry – the prediction of novel ultra-flexible boron oxide frameworks

We predict a wide range of ultra-flexible low-energy forms of boron oxides in which rigid B–O–B bridges link boron–oxygen heterocycles.</p

Structures and properties of solvated and unsolvated isopropyl functionalised calix[4]arenes

The tetra-iso-propyl ethers of calix[4]arene and p-t-butylcalix[4]arene have been isolated in the cone conformation, and structurally characterized as chloroform solvates. Thermogravimetric analysis demonstrated that the parent iso-propylcalix[4]arene solvate is significantly more stable than the p-t-butylcalix[4]arene analogue, retaining the solvent up to a temperature of of 125 °C. It was found that the calix[4]arene ether sublimes at atmospheric pressure, and solvent-free crystals appropriate for structure determination were produced at reduced pressure. The p-t-butylcalix[4]arene ether was also isolated without solvent in the lattice, but in this case the calixarene was crystallized from acetone, as sublimation did not produce crystals of sufficient quality

Using the NANA toolkit at home to predict older adults' future depression

Background: Depression is currently underdiagnosed among older adults. As part of the Novel Assessment of Nu-trition and Aging (NANA) validation study, 40 older adults self-reported their mood using a touchscreen computer over three, one-week periods. Here, we demonstrate the potential of these data to predict future depression status. Methods: We analysed data from the NANA validation study using a machine learning approach. We applied the least absolute shrinkage and selection operator with a logistic model to averages of six measures of mood, with depression status according to the Geriatric Depression Scale 10 weeks later as the outcome variable. We tested multiple values of the selection parameter in order to produce a model with low deviance. We used a cross-validation framework to avoid overspecialisation, and receiver operating characteristic curve (ROC) analysis to determine the quality of the fitted model. Results: The model we report contained coefficients for two variables: sadness and tiredness, as well as a constant. The cross-validated area under the ROC curve for this model was 0.88 (CI: 0.69–0.97). Limitations: While results are based on a small sample, the methodology for the selection of variables appears suitable for the problem at hand, suggesting promise for a wider study and ultimate deployment with older adults at increased risk of depression. Conclusions: We have identified self-reported scales of sadness and tiredness as sensitive measures which have the potential to predict future depression status in older adults, partially addressing the problem of underdiagnosis

‘What are you going to do, confiscate their passports?’ Professional perspectives on cross-border reproductive travel

Objective: This article reports findings from a UK-based study which explored the phenomenon of overseas travel for fertility treatment. The first phase of this project aimed to explore how infertility clinicians and others professionally involved in fertility treatment understand the nature and consequences of cross-border reproductive travel. Background: There are indications that, for a variety of reasons, people from the UK are increasingly travelling across national borders to access assisted reproductive technologies. While research with patients is growing, little is known about how ‘fertility tourism’ is perceived by health professionals and others with a close association with infertility patients. Methods: Using an interpretivist approach, this exploratory research included focussed discussions with 20 people professionally knowledgeable about patients who had either been abroad or were considering having treatment outside the UK. Semi-structured interviews were recorded, transcribed verbatim and subjected to a thematic analysis. Results: Three conceptual categories are developed from the data: ‘the autonomous patient’; ‘cross-border travel as risk’, and ‘professional responsibilities in harm minimisation’. Professionals construct nuanced, complex and sometimes contradictory narratives of the ‘fertility traveller’, as vulnerable and knowledgeable; as engaged in risky behaviour and in its active minimisation. Conclusions: There is little support for the suggestion that states should seek to prevent cross-border treatment. Rather, an argument is made for less direct strategies to safeguard patient interests. Further research is required to assess the impact of professional views and actions on patient choices and patient experiences of treatment, before, during and after travelling abroad

Stream food web response to a salmon carcass analogue addition in two central Idaho, U.S.A. streams

Pacific salmon and steelhead once contributed large amounts of marine-derived carbon, nitrogen and phosphorus to freshwater ecosystems in the Pacific Northwest of the United States of America (California, Oregon, Washington and Idaho). Declines in historically abundant anadromous salmonid populations represent a significant loss of returning nutrients across a large spatial scale. Recently, a manufactured salmon carcass analogue was developed and tested as a safe and effective method of delivering nutrients to freshwater and linked riparian ecosystems where marine-derived nutrients have been reduced or eliminated.We compared four streams: two reference and two treatment streams using salmon carcass analogue(s) (SCA) as a treatment. Response variables measured included: surface streamwater chemistry; nutrient limitation status; carbon and nitrogen stable isotopes; periphyton chlorophyll a and ash-free dry mass (AFDM); macroinvertebrate density and biomass; and leaf litter decomposition rates. Within each stream, upstream reference and downstream treatment reaches were sampled 1 year before, during, and 1 year after the addition of SCA.Periphyton chlorophyll a and AFDM and macroinvertebrate biomass were significantly higher in stream reaches treated with SCA. Enriched stable isotope (δ15N) signatures were observed in periphyton and macroinvertebrate samples collected from treatment reaches in both treatment streams, indicating trophic transfer from SCA to consumers. Densities of Ephemerellidae, Elmidae and Brachycentridae were significantly higher in treatment reaches. Macroinvertebrate community composition and structure, as measured by taxonomic richness and diversity, did not appear to respond significantly to SCA treatment. Leaf breakdown rates were variable among treatment streams: significantly higher in one stream treatment reach but not the other. Salmon carcass analogue treatments had no detectable effect on measured water chemistry variables.Our results suggest that SCA addition successfully increased periphyton and macroinvertebrate biomass with no detectable response in streamwater nutrient concentrations. Correspondingly, no change in nutrient limitation status was detected based on dissolved inorganic nitrogen to soluble reactive phosphorus ratios (DIN/SRP) and nutrient-diffusing substrata experiments. Salmon carcass analogues appear to increase freshwater productivity.Salmon carcass analogues represent a pathogen-free nutrient enhancement tool that mimics natural trophic transfer pathways, can be manufactured using recycled fish products, and is easily transported; however, salmon carcass analogues should not be viewed as a replacement for naturally spawning salmon and the important ecological processes they provide