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Reduction in diarrhoea rates after household water filter distribution in small and remote communities in Liberia

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Cogent Medicine 2023年第1期10卷

作者： K. R. Alford L. K. Walls S. L. DeRuiter R Pruim J. E. VanHorn M. Bone J. Deighton J. Koeman S. Kornoelje A. Koroma R. LeTourneau B. Lika K. Rosendale N. Wang 1 Public Health Program and Department of Social Work Calvin University Grand Rapids MI USA 2 Department of Mathematics and Statistics Calvin University Grand Rapids MI USA 3 Department of Geology Geography and Environment Calvin University Grand Rapids MI USA 4 The Last Well Monrovia Liberia 5 School of Global Health Institute of Health and Management Australia

Diarrhoea is the second-leading cause of death in Liberia, a sub-Saharan African country of 4.8 million people, with a majority living in rural villages. Diarrhoea has often been linked with poor water quality and malnutrition. Three organisations partnered to distribute point-of-use (POU) water filters to every household in Liberia without other access to safe water, documenting the distribution of filters to 101,706 households. Each such household was surveyed at a baseline, two weeks, and eight weeks. In addition to household characteristics, the prevalence of diarrhoea was reported at each survey. Our goal was to determine the extent of the impact that POU filter use had on diarrhoea prevalence by age group, controlling for effects of water source, location, and household size. Overall, there was a 94.2% decrease in diarrhoea cases from baseline to the 8-week follow-up. We discuss the success of the intervention in decreasing diarrhoea prevalence. The filter distribution focused on reaching remote villages, and providing access to clean water where there was none before. This study confirms that community-wide access to clean drinking water can reduce diarrhoea prevalence.

关键词： diarrhoea Liberia POU filter clean water

Revisiting AGN Placement on the BPT Diagram: A Spectral Decomposition Approach

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arXiv 2024年

作者： Teimoorinia, Hossen Shishehchi, Sara Archinuk, Finn Woo, Joanna Bickley, Robert Lin, Ping Hu, Zhonglin Petit, Emile NRC Herzberg Astronomy and Astrophysics 5071 West Saanich Road VictoriaBCV9E 2E7 Canada Department of Physics and Astronomy University of Victoria VictoriaBCV8P 5C2 Canada Signify Research US 1 Van de Graaff Drive BurlingtonMA01803 United States Department of Biomedical Engineering University of Alberta EdmontonABT6G 1H9 Canada Department of Physics Simon Fraser University 8888 University Dr BurnabyBCV5A 1S6 Canada Ciena 5050 Innovation Drive OttawaONK2K 0J2 Canada Department of Electrical and Computer Engineering University of Victoria 3800 Finnerty Road VictoriaBCV8P 5C2 Canada Departement of Mathematics and Statistics McGill University 845 Sherbrooke Street West MontrealQCH3A 0G4 Canada

Traditional single-fibre spectroscopy provides a single galaxy spectrum, forming the basis for crucial parameter estimation. However, its accuracy can be compromised by various sources of contamination, such as the prominent Hα emission line originating from both Star-Forming (SF) regions and non-Star-Forming regions (NonSF), including Active Galactic Nuclei (AGN). The potential to dissect a spectrum into its SF and NonSF constituents holds the promise of significantly enhancing precision in parameter estimates. In contrast, Integral Field Unit (IFU) surveys present a solution to minimize contamination. These surveys examine spatially localized regions within galaxies, reducing the impact of mixed sources. Although an IFU survey’s resulting spectrum covers a smaller region of a galaxy than single-fibre spectroscopy, it can still encompass a blend of heterogeneous sources. Our study introduces an innovative model informed by insights from the MaNGA IFU survey. This model enables the decomposition of galaxy spectra, including those from the Sloan Digital Sky Survey (SDSS), into SF and NonSF components. Applying our model to these survey datasets produces two distinct spectra, one for SF and another for NonSF components, while conserving flux across wavelength bins. When these decomposed spectra are visualized on a BPT diagram, interesting patterns emerge. There is a significant shift in the placement of the NonSF decomposed spectra, as well as the emergence of two distinct clusters in the LINER and Seyfert regions. This shift highlights the key role of SF ‘contamination’ in influencing the positioning of NonSF spectra within the BPT diagram. © 2024, CC BY.

关键词： Stars

Joint featurewise weighting and lobal structure learning for multi-view subspace clustering

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arXiv 2020年

作者： Lin, Shi-Xun Zhong, Guo Shu, Ting School of Mathematics and Statistics Zhaotong University Zhaotong657000 China Department of Computer and Information Science University of Macau China School of Information Technology and Electrical Engineering University of Queensland BrisbaneQLD4072 Australia

Multi-view clustering integrates multiple feature sets, which reveal distinct aspects of the data and provide complementary information to each other, to improve the clustering performance. It remains challenging to effectively exploit complementary information across multiple views since the original data often contain noise and are highly redundant. Moreover, most existing multi-view clustering methods only aim to explore the consistency of all views while ignoring the local structure of each view. However, it is necessary to take the local structure of each view into consideration, because different views would present different geometric structures while admitting the same cluster structure. To address the above issues, we propose a novel multi-view subspace clustering method via simultaneously assigning weights for different features and capturing local information of data in view-specific self-representation feature spaces. Especially, a common cluster structure regularization is adopted to guarantee consistency among different views. An efficient algorithm based on an augmented Lagrangian multiplier is also developed to solve the associated optimization problem. Experiments conducted on several benchmark datasets demonstrate that the proposed method achieves state-of-the-art performance. We provide the Matlab code on https://***/Ekin102003/JFLMSC. Copyright © 2020, The Authors. All rights reserved.

关键词： Cluster analysis

A well balanced finite volume scheme for general relativity

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arXiv 2021年

作者： Gaburro, Elena Castro, Manuel J. Dumbser, Michael INRIA Univ. Bordeaux CNRS Bordeaux INP IMB UMR 5251 200 Avenue de la Vieille Tour Talence Cedex33405 France Department of Mathematical Analysis Statistics and Applied Mathematics University of Málaga Campus de Teatinos Málaga29071 Spain Department of Civil Environmental and Mechanical Engineering University of Trento Via Mesiano 77 Trento38123 Italy

In this work we present a novel second order accurate well balanced (WB) finite volume (FV) scheme for the solution of the general relativistic magnetohydrodynamics (GRMHD) equations and the first order CCZ4 formulation (FO-CCZ4) of the Einstein field equations of general relativity, as well as the fully coupled FO-CCZ4 + GRMHD system. These systems of first order hyperbolic PDEs allow to study the dynamics of the matter and the dynamics of the space-time according to the theory of general relativity. The new well balanced finite volume scheme presented here exploits the knowledge of an equilibrium solution of interest when integrating the conservative fluxes, the nonconservative products and the algebraic source terms, and also when performing the piecewise linear data reconstruction. This results in a rather simple modification of the underlying second order FV scheme, which, however, being able to cancel numerical errors committed with respect to the equilibrium component of the numerical solution, substantially improves the accuracy and long-time stability of the numerical scheme when simulating small perturbations of stationary equilibria. In particular, the need for well balanced techniques appears to be more and more crucial as the applications increase their complexity. We close the paper with a series of numerical tests of increasing difficulty, where we study the evolution of small perturbations of accretion problems and stable TOV neutron stars. Our results show that the well balancing significantly improves the long-time stability of the finite volume scheme compared to a standard one. © 2021, CC BY.

关键词： Relativity

Recurrent dirichlet belief networks for interpretable dynamic relational data modelling

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arXiv 2020年

作者： Li, Yaqiong Fan, Xuhui Chen, Ling Li, Bin Yu, Zheng Sisson, Scott A. Centre for Artificial Intelligence University of Technology Sydney School of Mathematics & Statistics University of New South Wales Sydney Australia School of Computer Science Fudan University Department of Electrical and Computer Engineering Univeristy of Alberta

The Dirichlet Belief Network (DirBN) has been recently proposed as a promising approach in learning interpretable deep latent representations for objects. In this work, we leverage its interpretable modelling architecture and propose a deep dynamic probabilistic framework – the Recurrent Dirichlet Belief Network (Recurrent-DBN) – to study interpretable hidden structures from dynamic relational data. The proposed Recurrent-DBN has the following merits: (1) it infers interpretable and organised hierarchical latent structures for objects within and across time steps;(2) it enables recurrent long-term temporal dependence modelling, which outperforms the one-order Markov descriptions in most of the dynamic probabilistic frameworks;(3) the computational cost scales to the number of positive links only. In addition, we develop a new inference strategy, which first upward- and-backward propagates latent counts and then downward-and-forward samples variables, to enable efficient Gibbs sampling for the Recurrent-DBN. We apply the Recurrent-DBN to dynamic relational data problems. The extensive experiment results on real-world data validate the advantages of the Recurrent-DBN over the state-of-the-art models in interpretable latent structure discovery and improved link prediction performance. Copyright © 2020, The Authors. All rights reserved.

关键词： Bayesian networks

Design of Air Quality Monitoring System Based on Web Using Wireless Sensor Network 3

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Design of Air Quality Monitoring System Based on Web Using W...

3rd International Conference on Chemical and Material engineering, ICCME 2018

作者： Purwanto, P. Suryono, S. Sunarno, S. Doctorate Program of Environmental Science School of Postgraduates Studies Universitas Diponegoro Semarang Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Diponegoro Semarang Indonesia Department of Physics Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia

Air pollution (O3, SO2, CO, NOx, PM, and Pb) can have a severe impact on environmental damage and human health problems. Therefore, monitoring of pollutant levels in the air is essential to find out how much that gas levels can cause air pollution. In general, air quality monitoring is carried out using a conventional system. Inside the system requires large-sized equipment, long time for analysis, expensive, and with limited space resolution. It becomes inefficient, amid the development of technology that can carry out online monitoring, real-time, low cost, small size and a wide range of distance. The technology is known as the wireless sensor network system. The aim of this research is to design an air quality monitoring system using a Wireless Sensor Network (WSN) that can be accessed via the web and smartphone. The developing of WSN systems consist of two steps, are design and implementation device. The first step is done by assembling sensor nodes and hosting a web server. And after the device was finished, the next step is testing and calibrating of the system. The results of experiment show that the system is able to detect various air pollution, such as SO2, NOX, CO, and other environmental factors such as temperature, humidity and wind speed. © 2019 Published under licence by IOP Publishing Ltd.

关键词： Air quality

Migration, Adsorption and Formation Damage of Metal (Iii) Oxide Nanofluids in Reservoir Sandstone: Experimental and Simulation Studies

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SSRN

SSRN 2023年

作者： Hamza, Mohammed Falalu Soleimani, Hassan Lorimer, Shelley Sikiru, Surajudeen Olalekan Hassan, Yarima Mudassir Ahmed, Abdelazim Abbas Rostami, Amir Soleimani, Hojjatollah Demiral, Birol M.R. Centre for Subsurface Imaging Institute of Hydrocarbon Recovery Universiti Teknologi Petronas 32610 Bandar Seri Iskandar Perak Darul Ridzuan32610 Malaysia Department of Pure & Industrial Chemistry Faculty of Physical Sciences Bayero University Kano Kano3011 Nigeria Department of Mathematics and Statistics MacEwan University Edmonton Canada Institute of Power Engineering Universiti Tenaga Nasional Malaysia Malaysia Fundamental & Applied Science Department Universiti Teknologi Petronas 32610 Bandar Seri Iskandar Perak Darul Ridzuan32610 Malaysia Department of Energy and Petroleum Technology Faculty of Science and Technology University of Stavanger P.O Box 8600 Stavanger4036 Norway Department of Physics North Tehran Branch Islamic Azad University Tehran16511-5311 Iran Schlumberger NExT Dubai International Financial Centre Burj Daman Building Floor 9 PO Box Dubai506579 United Arab Emirates

This paper studied the transport, adsorption, retention, and formation damage of two metallic (III) oxide nanoparticles (NP: Al2O3 & Fe2O3) in sandstone core plugs. The migration of NP was evaluated by monitoring the pressure drops (∆p) during core flooding with brine (pre-NP) at 0.2 mL min-1, then with nanofluids and lastly with another slug of brine (post-NP). While the formation damage was assessed by the changes in permeability (K), porosity () and other core properties due to nanofluid injections. The adsorption study was performed by constructing reservoir configurations using Material Studio Software. Results have shown that nanofluids have higher ∆p (s) than the pre-NP baselines. This is mainly due to the adsorption and straining of NP, indicating advanced NP migration and propagation. During Al2O3 flooding, the ∆p reached its maximum at 2.1 psi and later subsided to 1.596 ± 0.13 psi within 3 pore volume of injection. This behavior was similarly displayed by its counterpart Fe2O3 but having lower ∆p max. at 1.6 psi and relaxed at 1.264 ± 0.08 psi. Accordingly, the ∆p of post-NP in the Al2O3 core was around 1.588 ± 0.3, which was higher than its pre-NP by 109 %. In the Fe2O3 core, the post-NP was higher than its pre-NP injection by 93 %, indicating retention of both NP. The K reductions after the experiments were 12 and 8 % for Al2O3 and Fe2O3, respectively. Also, the reductions (18 %) caused by Al2O3 were higher than the Fe2O3 NP (15 %). Furthermore, Al2O3 has shown strong adsorption activation energy than the Fe2O3. © 2023, The Authors. All rights reserved.

关键词： Adsorption

Strengthening the Link Between Fullerenes and a Subset of Diffuse Interstellar Bands

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arXiv 2025年

作者： Majaess, Daniel Harriott, Tina A. Seuret, Halis Morera-Boado, Cercis Massa, Lou Matta, Chérif F. Department of Chemistry and Physics Mount Saint Vincent University HalifaxNSB3M2J6 Canada Department of Mathematics and Statistics Mount Saint Vincent University HalifaxNSB3M2J6 Canada Centro de Investigaciones Químicas IICBA Universidad Autónoma del Estado de Morelos Morelos Cuernavaca62209 Mexico IXM-Cátedra Conahcyt-Centro de Investigaciones Químicas IICBA Universidad Autónoma del Estado de Morelos Morelos Cuernavaca62209 Mexico Hunter College The PhD Program of the Graduate Center City University of New York New York United States Department of Chemistry Saint Mary’s University HalifaxNSB3H3C3 Canada Département de Chimie Université Laval QuébecG1V0A6 Canada Department of Chemistry Dalhousie University HalifaxNSB3H4J3 Canada

A debate persists regarding the correlation between the DIBs 9577 and 9632 Å, and whether they share a common molecular carrier (i.e., C+60). A robust high correlation determination emerges after bridging the baseline across an order of magnitude ( 50 − 700 mÅ, r = 0.93 ± 0.02), and nearly doubling the important higher equivalent width domain by adding new Mg II-corrected sightlines. Moreover, additional evidence is presented of possible DIB linkages to fullerenes, whereby attention is drawn to DIBs at 7470.38, 7558.44, and 7581.47 Å, which match the Campbell experimental results for C+70 within 1 Å, and the same is true of 6926.48 and 7030.26 Å for C2+70 . Yet their current correlation uncertainties are unsatisfactory and exacerbated by expectedly low EWs (e.g., EW = 4 mÅ for 6926.48 Å), and thus further observations are required to assess whether they represent a bona fide connection or numerical coincidence. © 2025, CC BY.

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Distance between natural numbers based on their prime signature

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arXiv 2020年

作者： Kolossváry, István B. Kolossváry, István T. Boston University Department of Biomedical Engineering BostonMA02215 United States The University of St Andrews School of Mathematics and Statistics St AndrewsKY16 9SS United Kingdom

We define a new metric between natural numbers induced by the l∞ norm of their unique prime signatures. In this space, we look at the natural analog of the number line and study the arithmetic function L∞(N), which tabulates the cumulative sum of distances between consecutive natural numbers up to N in this new metric. Our main result is to identify the positive and finite limit of the sequence L∞(N)/N as the expectation of a certain random variable. The main technical contribution is to show with elementary probability that for K = 1, 2 or 3 and ω0,..., ωK ≥ 2 the following asymptotic density holds (Equation presented). This is a generalization of the formula for k-free numbers, i.e. when ω0 =... = ωK = k. The random variable is derived from the joint distribution when K = 1. As an application, we obtain a modified version of the prime number theorem. Our computations up to N = 1012 have also revealed that prime gaps show a considerably richer structure than on the traditional number line. Moreover, we raise additional open problems, which could be of independent *** Codes Primary 11N64 11K65 Secondary 11N37 11Y70 11-04 Copyright © 2020, The Authors. All rights reserved.

关键词： Number theory