Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems

A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand

Rare-metal granites as a potential source of critical metals: A geometallurgical case study

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordBecause of their low grades in critical metals such as Light Rare Earth Elements (LREE) or Sn, rare-metal granites are not considered as economic for metal recovery but, when altered, they are often exploited for their industrial minerals. The St Austell rare-metal granite is well known for its world-class kaolin deposits which formed as a result of the extensive weathering and alteration of the underlying granite. The St Austell granite body is composed of several granite components, each having its own accessory minerals assemblage. As a result of the kaolinisation process, some metal-bearing accessory minerals of the granite, such as monazite (LREE) or cassiterite (Sn), are partially liberated from the gangue which allow their pre-concentration in the micaceous residue which is considered as a potential source for critical metals recovery. Similarities with other similar rare-metal granites suggest that topaz granite is the most prospective for disseminated magmatic Sn-Nb-Ta-REE mineralization. However, comparison of the potentiality of 3 granite types i.e., biotite, topaz and tourmaline granites suggest that biotite granites is actually the most prospective due to higher degree of kaolinisation of the biotite granite which favour pre-concentration of its accessory mineral in the micaceous residue. In order to develop a geometallurgical framework for extraction of kaolin and metals from the selected granite component, a field sampling campaign is performed. Core samples are processed in the laboratory using a characterisation program that mimics the full-scale kaolin refining route. Two main products are recovered through this program, viz. MR180 (−180 +53 µm) and P5 (−5 µm), which correspond to a fine micaceous residue and a fine kaolin product respectively. These products are both analysed routinely for major and minor trace elements by XRF and yields are recorded to indicate process performance. A selected number of MR180 samples are also being characterised in terms of particle size by laser light scattering, geochemistry by ICP-MS, and mineralogy by QEMSCAN®. Comparison of characterisation results of MR180 samples and corresponding industrial residue samples shows a good correlation, suggesting that sample analyses are representative for the in-situ deposit and the processing behaviour. Monazite is found to be either fully liberated or fully locked from one sample to the other. Next, pilot-scale gravity concentration tests are performed on micaceous residue samples. Characterisation of the processing products shows that monazite lost in the tailings is mostly locked within tourmaline or micas and is fine grained. Then, predictive regression models for spiral separation performance in terms of recovery, product grade and enrichment as a function of the feed grade are developed for MR180 LREE grade data. Finally, kaolin resources can be classified using quantitative indicators such as yield of the P5 product and the iron oxides content which provides insight into the kaolin quality in terms of whiteness. This geometallurgical classification can be used to delineate zones of interest within the deposit. Although kaolin quality and recovery primarily inform extraction planning, zones which are also of interest for metal recovery can be identified. The proposed model predicts whether the expected LREE grade and recovery satisfy the by-product requirements.European CommissionNatural Environment Research Council (NERC)French National Research Agenc

Rancang Bangun Sistem Simulasi Denyut Nadi Pergelangan Tangan pada Vital Sign Simulator sebagai Media Pembelajaran Keterampilan Medik Mahasiswa Kedokteran

Salah satu kompetensi yang harus dikuasai oleh mahasiswa kedokteran/calon dokter adalah keterampilan klinik. Komponen keterampilan klinik ini meliputi pemeriksaan fisik berupa tanda vital (vital sign) dari seorang pasien. Diperlukan pelatihan keterampilan pemeriksaan tanda vital khususnya denyut nadi untuk meningkatkan kompetensi calon dokter tersebut. Oleh karena itu perlu dikembangkan simulator denyut nadi pada pergelangan tangan/artery radialis berbasis simulasi pasien berupa jaket/kaos menset yang dilengkapi “sistem pintar”. Dengan demikian mahasiswa kedokteran dapat berlatih pengukuran tanda vital dengan tetap memperhatikan etika komunikasi dan profesionalisme. Pada penelitian ini rancang bangun sistem simulasi denyut nadi dengan menggunakan mikrokontroller ATMega16 dan aktuator berupa katup solenoid serta pompa udara. Data yang ditampilkan di LCD berupa pencacah denyut nadi, set point jumlah denyut nadi, dan timer.Dari penelitian ini dihasilkan rancang bangun alat simulasi denyut nadi pada pergelangan tangan/artery radialis dengan rentang 0-180 denyut/menit dan memiliki tingkat akurasi sebesar 99,98% dari metode Palpasi dan 99,95% dari metode penggunaan sensor piezoelectric

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Enhanced weathering of olivine to capture CO2

Mankind suffers from fixation on technology fixes. This is probably the main reason why the obvious choice to counteract climate change has been overlooked so long, namely to help mother nature to do what it has always been doing. A novel way of using olivine against climate change is proposed, not as a chemical in a technology, but in the same way it works in nature. Chemical weathering of olivine and other calcium and magnesium silicates has always been the main mechanism to keep the C02 levels of the atmosphere within reasonable bounds, with storage of organic carbon a distant second. At present this mechanism cannot cope with the increased input of C02 caused by the burning of fossil fuels. In order to reach a new balance we must increase the rate of weathering as well. This can be done by mining abundant rock types that weather easily, grind them, and spread the powder in a thin veneer over large areas in wet tropical climates, where weathering rates are highest. The reaction that is relevant to combat climate change is the transformation of C02 into the bicarbonate in solution. Ultimately these bicarbonate solutions will reach the oceans and precipitate as carbonate sediments, but this is a slow process which extends well beyond the time span of concern. Some considerations on rates of weathering, based on observations from geology and soil science are given. They turn out to be considerably higher than rates calculated on the basis of abiotic laboratory experiments