Agricultural Perspectives in the Tsetse Infested Areas in Africa

Understanding the nature and dimension of the food problem and the policies available to alleviate it has been the focal point of the Food and Agriculture Programme (FAP) at the International Institute for Applied Systems Analysis (IIASA) since the program began in 1977. Large areas of Africa are infested by tsetse flies which preclude certain types of agricultural development. Should one consider an international effort to eradicate or contain tsetse flies? The problem is complex, as the entire ecology of that vast area may be affected by it. Though one must evaluate these ecological consequences in such decisions, an understanding of the agricultural production potential of the tsetse infested areas is an important element in analyzing such policy questions. The authors have provided agricultural perspectives for the tsetse infested areas in Africa. We are grateful to the Food and Agriculture Organization of the United Nations for partially supporting this study

Characterising post-medieval pottery production centres in Somerset

This is the final version. Available from the Medieval Pottery Research Group via the link in this recordPost-medieval pottery made in Somerset is distinct from wares produced elsewhere in the south-west of England. Recent experimental work and scientific analysis, combined with study of finds from fieldwork, has led to a more complete understanding of the nature of pottery production in Somerset, how it is possible to use mineralogical and stylistic evidence to distinguish between the three major areas of earthenware production and how production changes over time

Flotation of mixed oxide sulphide copper-cobalt minerals using xanthate, dithiophosphate, thiocarbamate and blended collectors

This is the final version. Available on open access from the publisher via the DOI in this recordMore than half of the global cobalt supply from primary sources is currently produced in the Democratic Republic of Congo (DRC) from ores containing copper-cobalt oxides or copper-cobalt sulphides. Where oxide and sulphide cobalt-bearing copper minerals occur together, efficient recovery of copper and cobalt is known to be extremely difficult. This study investigates the flotation behaviour of a mixed oxide-sulphide ore where copper is hosted in sulphides phases such as bornite, chalcopyrite and chalcocite, and oxide phases such as malachite and to a lesser extent chrysocolla. Three cobalt-bearing oxide minerals are observed in the mixed ore, i.e. heterogenite, kolwezite and cupro-asbolane, while carrollite is the only cobalt-bearing sulphide mineral. A two-stage rougher-scavenger flotation process is used in which sulphides are extracted from the ore first. In the second stage, oxides are activated using controlled potential sulphidisation followed by their recovery. Tests are performed with a range of collectors, including xanthate, phosphorodithioate, dithiophosphate, thiocarbamate, and a blend type. A dithiophosphate collector proved to the most successful, achieving recovery of 94% of the carrollite, more than 90% of the copper sulphides, and 70% of the copper oxide minerals. The recovery of the cobalt oxides was less successful, with recovery of roughly half the kolwezite and only 20% of the heterogenite and cupro-asbolane. Despite the generally promising recoveries, the selectivity of the flotation process is relatively low with all the concentrates containing a significant amount of carbonate and silicate minerals. This suggests that a number of improvements require further investigation, notably the application of hydroxamate collectors, depressants and reverse flotationNatural Environment Research Council (NERC

A Process Mineralogy Approach to Gravity Concentration of Tantalum Bearing Minerals

This is the final version of the article. Available from MDPI via the DOI in this record.The historic Penouta mine in northwest Spain is the focus of efforts to extract tantalum from tin mining waste. This paper describes the characterisation of the tantalum mineralogy of waste material from the deposit. Characterisation was realised using quantitative mineralogy and geochemistry. This paper further identifies other phases of interest and investigates the potential for extraction using gravity separation techniques. The gravity concentrate obtained through these tests was analysed using quantitative mineralogy and electron probe microanalysis. Following characterisation of the sample material to identify the key Ta-bearing mineral phases and assess liberation, a series of gravity separation trials were conducted using Heavy Liquid Separation (HLS), Mozley table, Knelson concentrator separation and shaking table. The laboratory shaking table used to conduct a rougher test and a rougher/cleaner test to simulate a spiral-table circuit using the Penouta material. Mass balance calculations were carried out to calculate the contained metal content of the feed material and concentrate products in order to assess recovery rates for Ta, Sn and Nb across a range of grains sizes. Ta was found to be present predominantly in the solid-solution columbite-group mineral, along with minor Ta present as microlite and as impurities within cassiterite. It was found that over 70% of the Ta is contained within the −125 μm fraction, with the Ta-bearing minerals tantalite and microlite being closely associated with quartz. Mozley table separation resulted in recoveries of 89% Ta and 85% Nb for the −125 μm fraction. The Knelson Concentrator trial was carried out on the −625 μm size fraction, thereby eliminating low grade material found in the coarsest fractions. Size analysis of the recovery rate for each product, shows that the Knelson concentrator is most efficient for recovery of −125 μm particles.This work is part of the OptimOre project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642201. Authors are thankful from the Strategic Minerals enterprise for their help in sampling, visit and information provided

Optimisation of a Multi-Gravity Separator with Novel Modifications for the Recovery of Ferberite

This is the final version of the article. Available from MDPI via the DOI in this record.Tungsten is considered by the European Union as a critical raw material for future development due to its expected demand and scarcity of resource within Europe. It is therefore, critical to optimize European tungsten operations and maximise recoveries. The role of enhanced gravity/centrifugal concentrators in recovering tungsten from ultra-fine fractions should form an important part of this aim. Reported herein are the results of investigations to improve efficiency of Wolf Minerals’ Draklends mine, a major European tungsten mine, by recovering saleable material from a magnetic waste stream of a low-intensity magnetic separator using an enhanced gravity concentrator. The mine hosts wolframite and ferberite as the main tungsten bearing mineral species. A Mozley multi-gravity separator (MGS) C-900 was selected as it is suited to exploiting small variations in mineral density to affect a separation. Working with a current manufacturer, a novel scraping blade system was tested. To assess the MGS in a statistically valid manner, a response surface methodology was followed to determine optimal test conditions. The test programme showed that the most important parameters were drum speed and wash water rate. Under optimal conditions the model predicted that 40% of the tungsten could be recovered above the required grade of 43% WO3.This work is part of the OptimOre project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642201. Authors are thankful to Wolf Minerals for providing material for experimentation and to Gravity Mining Ltd. for support in undertaking experiments and providing the opportunity to test the modified low profile blades

Effective elements of cognitive behaviour therapy for psychosis: results of a novel type of subgroup analysis based on principal stratification

Background. Meta-analyses show that cognitive behaviour therapy for psychosis (CBT-P) improves distressing positive symptoms. However, it is a complex intervention involving a range of techniques. No previous study has assessed the delivery of the different elements of treatment and their effect on outcome. Our aim was to assess the differential effect of type of treatment delivered on the effectiveness of CBT-P, using novel statistical methodology. Method. The Psychological Prevention of Relapse in Psychosis (PRP) trial was a multi-centre randomized controlled trial (RCT) that compared CBT-P with treatment as usual (TAU). Therapy was manualized, and detailed evaluations of therapy delivery and client engagement were made. Follow-up assessments were made at 12 and 24 months. In a planned analysis, we applied principal stratification (involving structural equation modelling with finite mixtures) to estimate intention-to-treat (ITT) effects for subgroups of participants, defined by qualitative and quantitative differences in receipt of therapy, while maintaining the constraints of randomization. Results. Consistent delivery of full therapy, including specific cognitive and behavioural techniques, was associated with clinically and statistically significant increases in months in remission, and decreases in psychotic and affective symptoms. Delivery of partial therapy involving engagement and assessment was not effective. Conclusions. Our analyses suggest that CBT-P is of significant benefit on multiple outcomes to patients able to engage in the full range of therapy procedures. The novel statistical methods illustrated in this report have general application to the evaluation of heterogeneity in the effects of treatment

Geotechnical and mineralogical characterisations of marine dredged sediments before and after stabilisation to optimise their use as a road material

ArticleThis is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.Dredging activities to extend, deepen and maintain access to harbours generate significant volumes of waste dredged material. Some ways are investigated to add value to these sediments. One solution described here is their use in road construction following treatment with hydraulic binders. This paper presents the characterisation of four sediments, in their raw state and after 90 days of curing following stabilisation treatment with lime and cement, using a combination of novel and established analytical techniques to investigate subsequent changes in mineralogy. These sediments are classified as fine, moderately to highly organic and highly plastic and their behaviour is linked to the presence of smectite clays. The main minerals found in the sediments using X-rays diffraction (XRD) and automated mineralogy are quartz, calcite, feldspars, aluminium silicates, pyrite and halite. Stabilisation was found to improve the mechanical performances of all the sediments. The formation of cementitious hydrates was not specifically detected using automated mineralogy or XRD. However, a decrease in the percentage volume of aluminium silicates and aluminium-iron silicates and an increase of the percentage volume of feldspars and carbonates was observed.The authors thank the all the partners having participate to the dredging operations; Lhoist and Lafarge for their technical and scientifical supports; Europe, European Regional Development Fund (ERDF), Interreg IVA and Regional Council of Basse-Normandie for their financial support to the Sustainable and Environmental Treatment And Reuse of Marine Sediment (SETARMS) project

Study and implementation of urogenital schistosomiasis elimination in Zanzibar (Unguja and Pemba islands) using an integrated multidisciplinary approach

ABSTRACT: BACKGROUND: Schistosomiasis is a parasitic infection that continues to be a major public health problem in many developing countries being responsible for an estimated burden of at least 1.4 million disability-adjusted life years (DALYs) in Africa alone. However, morbidity due to schistosomiasis has been greatly reduced in some parts of the world, including Zanzibar. The Zanzibar government is now committed to eliminate urogenital schistosomiasis. Over the next 3--5 years, the whole at-risk population will be administered praziquantel (40 mg/kg) biannually. Additionally, snail control and behaviour change interventions will be implemented in selected communities and the impact measured in a randomized intervention trial. METHODS: In this 5-year research study, on both Unguja and Pemba islands, urogenital schistosomiasis will be assessed in 45 communities with urine filtration and reagent strips in 4,500 schoolchildren aged 9--12 years annually, and in 4,500 first-year schoolchildren and 2,250 adults in years 1 and 5. Additionally, from first-year schoolchildren, a finger-prick blood sample will be collected and examined for Schistosoma haematobium infection biomarkers. Changes in prevalence and infection intensity will be assessed annually. Among the 45 communities, 15 were randomized for biannual snail control with niclosamide, in concordance with preventive chemotherapy campaigns. The reduction of Bulinus globosus snail populations and S. haematobium-infected snails will be investigated. In 15 other communities, interventions triggering behaviour change have been designed and will be implemented in collaboration with the community. A change in knowledge, attitudes and practices will be assessed annually through focus group discussions and in-depth interviews with schoolchildren, teachers, parents and community leaders. In all 45 communities, changes in the health system, water and sanitation infrastructure will be annually tracked by standardized questionnaire-interviews with community leaders. Additional issues potentially impacting on study outcomes and all incurring costs will be monitored and recorded. DISCUSSION: Elimination of schistosomiasis has become a priority on the agenda of the Zanzibar government and the international community. Our study will contribute to identifying what, in addition to preventive chemotherapy, needs to be done to prevent, control, and ultimately eliminate schistosomiasis, and to draw lessons for current and future schistosomiasis elimination programmes in Africa and elsewhere.Trial registrationISRCTN4883768

Mineralogical study of the Gonçalo Li-pegmatite deposit, Portugal

Beside the Scandinavian countries and Serbia, Portugal is among the European countries with the most significant lithium resources. The Li-rich occurrences in Portugal are mainly associated with aplite-pegmatite dykes and sills intruded in granitic and metasedimentary rocks of the Central Iberian and Galicia – Trás-os-Montes geotectonic zones (Carvalho & Farinha, 2004). The Gonçalo Li-pegmatites in the Guarda district (currently only used as decorative stone) have significant economic importance. Among other deposits, Gonçalo is a reference site in the focus of the EU FAME project (www.fame-project.eu) that aims to unlock the development potential of the most promising European Sn-W-Li ore types. Results of optical microscopy, QEMSCAN©, Raman and electron-probe microanalysis of the Gonçalo Li-pegmatite deposit have been employed to determine the mineralogical variability of the pegmatites with the aim to determine the deportment of lithium and potential rare-metal by-products and to guide enhanced mineral processing technologies.Available to download freely and reproduced here with permission of the publisher. The attached file is the published pdf