35 research outputs found

    Nanoplankton : the dominant vector for carbon export across the Atlantic Southern Ocean in spring

    Get PDF
    DATA AND MATERIAL AVAILABILITY : The data used in this manuscript are available in the Zenodo data repository: 10.5281/zenodo.7820428. All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.SUPPLEMENTARY MATERIAL : Supplementary Text; Figs. S1 to S4; Tables S1 and S2.Across the Southern Ocean, large (≄20 ÎŒm) diatoms are generally assumed to be the primary vector for carbon export, although this assumption derives mainly from summertime observations. Here, we investigated carbon production and export potential during the Atlantic Southern Ocean’s spring bloom from size-fractionated measurements of net primary production (NPP), nitrogen (nitrate, ammonium, urea) and iron (labile inorganic iron, organically complexed iron) uptake, and a high-resolution characterization of phytoplankton community composition. The nanoplankton-sized (2.7 to 20 ÎŒm) diatom, Chaetoceros spp., dominated the biomass, NPP, and nitrate uptake across the basin (40°S to 56°S), which we attribute to their low iron requirement, rapid response to increased light, and ability to escape grazing when aggregated into chains. We estimate that the spring Chaetoceros bloom accounted for >25% of annual export production across the Atlantic Southern Ocean, a finding consistent with recent observations from other regions highlighting the central role of the phytoplankton “middle class” in carbon export.The South African National Research Foundation, South African National Antarctic Programme, University of Cape Town Science Faculty Fellowship, University of Cape Town Vice-Chancellor Doctoral Research Scholarship, University of Cape Town Vice-Chancellor Future Leaders 2030 Award, European Union’s Horizon 2020 Research and Innovation Programme No. 844733, Academy of Finland, and Funds from an Anonymous Charitable Donor Trust as part of Whales and Climate Change Program.https://www.science.org/journal/sciadvhj2024GeneticsSDG-14:Life below wate

    Antibacterial and dermal toxicological profiles of ethyl acetate extract from Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The emergence in recent years of numerous resistant strains of pathogenic bacteria to a range of formerly efficient antibiotics constitutes a serious threat to public health. <it>Crassocephalum bauchiense</it>, a medicinal herb found in the West Region of Cameroon is used to treat gastrointestinal infections as well as liver disorders. The ethyl acetate extract from the leaves of <it>C. bauchiense </it>was evaluated for its antibacterial activity as well as acute and sub-acute toxicities.</p> <p>Methods</p> <p>The plant extract was prepared by maceration in ethyl acetate. Its phytochemical screening was done by standard methods. The broth microdilution method was used to evaluate the <it>in vitro </it>antibacterial activity. The <it>in vivo </it>antibacterial activity of a gel formulation (0.05, 1 and 2% w/v) of this extract was evaluated using a <it>Staphylococcus aureus</it>-induced dermatitis in a murine model. Selected haematological and biochemical parameters were used to evaluate the dermal sub-acute toxicity of the extract in rats.</p> <p>Results</p> <p>Phytochemical screening of the <it>C. bauchiense </it>extract revealed the presence of alkaloids, phenols, tannins and sterols. <it>In vitro </it>antibacterial activities were observed against all the tested microorganisms (MIC = 0.04-6.25 mg/ml). Formulated extract-gel (2% w/v) and gentamycin (reference drug) eradicated the microbial infection after five days of treatment. A single dermal dose of this extract up to 32 g/kg body weight (bw) did not produce any visible sign of toxicity. Also, daily dermal application of the <it>C. bauchiense </it>extract gel formulation for 28 days did not show any negative effect, instead some biochemical parameters such as alanine aminotransferase (ALT and AST), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides were significantly (p < 0.05) affected positively.</p> <p>Conclusion</p> <p>These results indicate that the <it>C. bauchiense </it>ethyl acetate extract can be used safely for the treatment of some bacterial infections.</p

    Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.

    Get PDF
    BACKGROUND: Child stunting reduces survival and impairs neurodevelopment. We tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF) on stunting and anaemia in in Zimbabwe. METHODS: We did a cluster-randomised, community-based, 2 × 2 factorial trial in two rural districts in Zimbabwe. Clusters were defined as the catchment area of between one and four village health workers employed by the Zimbabwe Ministry of Health and Child Care. Women were eligible for inclusion if they permanently lived in clusters and were confirmed pregnant. Clusters were randomly assigned (1:1:1:1) to standard of care (52 clusters), IYCF (20 g of a small-quantity lipid-based nutrient supplement per day from age 6 to 18 months plus complementary feeding counselling; 53 clusters), WASH (construction of a ventilated improved pit latrine, provision of two handwashing stations, liquid soap, chlorine, and play space plus hygiene counselling; 53 clusters), or IYCF plus WASH (53 clusters). A constrained randomisation technique was used to achieve balance across the groups for 14 variables related to geography, demography, water access, and community-level sanitation coverage. Masking of participants and fieldworkers was not possible. The primary outcomes were infant length-for-age Z score and haemoglobin concentrations at 18 months of age among children born to mothers who were HIV negative during pregnancy. These outcomes were analysed in the intention-to-treat population. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes that had an important statistical interaction between the interventions. This trial is registered with ClinicalTrials.gov, number NCT01824940. FINDINGS: Between Nov 22, 2012, and March 27, 2015, 5280 pregnant women were enrolled from 211 clusters. 3686 children born to HIV-negative mothers were assessed at age 18 months (884 in the standard of care group from 52 clusters, 893 in the IYCF group from 53 clusters, 918 in the WASH group from 53 clusters, and 991 in the IYCF plus WASH group from 51 clusters). In the IYCF intervention groups, the mean length-for-age Z score was 0·16 (95% CI 0·08-0·23) higher and the mean haemoglobin concentration was 2·03 g/L (1·28-2·79) higher than those in the non-IYCF intervention groups. The IYCF intervention reduced the number of stunted children from 620 (35%) of 1792 to 514 (27%) of 1879, and the number of children with anaemia from 245 (13·9%) of 1759 to 193 (10·5%) of 1845. The WASH intervention had no effect on either primary outcome. Neither intervention reduced the prevalence of diarrhoea at 12 or 18 months. No trial-related serious adverse events, and only three trial-related adverse events, were reported. INTERPRETATION: Household-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. FUNDING: Bill & Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Development Cooperation, UNICEF, and US National Institutes of Health.The SHINE trial is funded by the Bill & Melinda Gates Foundation (OPP1021542 and OPP113707); UK Department for International Development; Wellcome Trust, UK (093768/Z/10/Z, 108065/Z/15/Z and 203905/Z/16/Z); Swiss Agency for Development and Cooperation; US National Institutes of Health (2R01HD060338-06); and UNICEF (PCA-2017-0002)

    Kent Mixture Model for Hyperspectral Clustering via Cosine Pixel Coordinates on Spherical Manifolds

    Get PDF
    Modern hyperspectral imaging sensor technology provides detailed spectral and spatial information that enables precise analysis of land cover usage. From a research point of view, traditional widely used statistical models are often limited in the sense that they do not incorporate some of the useful angle information contained in the feature vectors, and hence alternative modeling methods are required. In the study to be presented, the use of cosine angle information and its embedding onto a spherical manifold is investigated. The transformation of hyperspectral images onto a unit hyperspherical manifold is achieved by using the recently proposed spherical local embeddings approach. Spherical local embeddings is a method that computes high-dimensional local neighborhood preserving coordinates of data on constant curvature manifolds. We further develop a novel Kent mixture model for unsupervised classification of embedded cosine pixel coordinates. A Kent distribution is one of the natural models for multivariate data on a spherical manifold. Parameters for the model are estimated using the Expectation-Maximization procedure. The mixture model is applied to two different Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) datasets that were acquired from the Tippecanoe County in Indiana. The results obtained present insights on cosine pixel coordinates and also serve as a motivation for further development of new models to analyze hyperspectral images in spherical manifolds

    PEMBUATAN SISTEM INFORMASI OBYEK WISATA BERBASIS WEB MENGGUNAKAN MAPSERVER ( Studi Kasus : Kota Batu )

    No full text
    Kota Batu merupakan salah satu wilayah di Jawa Timur yang memiliki potensi obyek wisata yang besar. Namun potensi obyek wisata ini tidak dapat diketahui oleh wisatawan, dikarenakan kurangnya informasi tentang obyek wisata di Kota Batu. Disamping itu, informasi yang disediakan selama ini hanya bersifat statis. Mengacu pada pemahaman tersebut maka penelitian ini mengkaji sebuah penyajian informasi untuk Obyek Wisata Kota Batu memanfaatkan WEBGIS dengan menggunakan MapServer OpenSource, MySQL, PHP/Mapscript dan ArcGIS. Penelitian ini menghasilkan sebuah sistem informasi tentang obyek wisata di Kota Batu yang berbasis web yang didalamnya juga terdapat informasi jenis wisata, lokasi obyek wisata,dan deskripsi obyek wisata serta foto obyek wisata. Kata Kunci : Kota batu, Obyek Wisata, WebGI

    Stress testing techniques and value-at-risk measures: A unified approach

    No full text
    Viene proposta una metodologia per costruire scenari coerenti per analisi distress testing nel controllo dei rischi finanziari. Il metodo, basato sull'approccio bayesiano di Black e Litterman per l'ottimizzazione del portafoglio, consente di anire informazione storica e implicita, pubblica e privata, in modo da tenere conto della struttura di dipendenza tra i mercati. Aggiustando i valori medi di ciascuno scenario ed il grado di precisione attribuito a ciascuno di essi siano in grado di generare un insieme di misure di perdita media o di massima perdita probabile, come il Value-at-Risk. In particolare, se lo scenario ù molto preciso la perdita media e la massima perdita probabile tendono a convergere, mentre se il grado di confidenza nello scenario ù molto basso la perdita media converge verso zero e la massima perdita probabile coincide con la nota misura di Value-at-Risk basata sull'informazione storica. L'analisi ù applicabile anche a prodotti non lineari come le opzioni, per le quali mostriamo che l'aggiustamento della precisione degli scenari corrisponde all'analisi di sensitività rispetto a cambiamenti di volatilità. Infine, per posizioni complesse, come quelle che riguardano l'esposizione al rischio di credito, o posizioni di segno diverso su mercati diversi, suggeriamo un modello a “alberi” per la determinazione degli scenari rilevanti e l'identificazione delle fonti di rischio maggiori della posizione. Copyright Associazione per la Matematica Applicata alle Scienze Economiche e Sociali (AMASES) 1999

    Repurposing legacy metallurgical data Part I : A move toward dry laboratories and data bank

    No full text
    Advancements in modern mineral processing has been driven by technology and fuelled by market economics of supply and demand. Over the last three decades, the demand for various minerals has steadily increased, while the mineral processing industry has seen an unavoidable increase in the treatment of complex ores, continuous decline in plant feed grade and poor plant performance partly due to blending of ores with dissimilar properties. Despite these challenges, production plant data that are routinely generated are usually underutilised. In this contribution and aligned with the direction of the 4th industrial revolution, we highlight the value of legacy metallurgical plant data and the concept of a dry laboratory approach. This study is presented in two parts. In the current paper (Part I), a comprehensive review of the potential for the combination of modern analytical technology with data analytics to generate a new competence for process optimisation are provided. To demonstrate the value of data within the extractive metallurgy discipline, we employ data analytics and simulation to examine gold plant performance and the flotation process in two separate case studies in the second paper (Part II). This was done with the aim of showcasing relevant plant data insights, and extract parameters that should be targeted for plant design and performance optimisation. We identify several promising technologies that integrate well with existing mineral processing plants and testing laboratories to exploit the concept of a dry laboratory, in order to enhance pre-existing mineral processing chains. It also sets the passage in terms of the value of innovative analysis of existing and simulation data as part of the new world of data analytics. Using data- and technology-driven initiatives, we propose the establishment of dry laboratories and data banks to ultimately leverage integrated data, analytics and process simulation for effective plant design and improved performance.Validerad;2020;NivÄ 2;2020-09-29 (alebob)</p

    Electricity consumption patterns within cities: application of a data-driven settlement characterization method

    No full text
    Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns
    corecore