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APPROXIMATING THE STATIONARY BELLMAN EQUATION BY HIERARCHICAL TENSOR PRODUCTS

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Journal of Computational Mathematics 2024年第3期42卷 638-661页

作者： mathias Oster Leon Sallandt Reinhold Schneider Technische Universität Berlin Strasse des 17.Juni 13510623 BerlinGermany

We treat infinite horizon optimal control problems by solving the associated stationary Bellman equation numerically to compute the value function and an optimal feedback *** dynamical systems under consideration are spatial discretizations of non linear parabolic partial differential equations(PDE),which means that the Bellman equation suffers from the curse of *** non linearity is handled by the Policy Iteration algorithm,where the problem is reduced to a sequence of linear equations,which remain the computational bottleneck due to their high *** reformulate the linearized Bellman equations via the Koopman operator into an operator equation,that is solved using a minimal residual *** the Koopman operator we identify a preconditioner for operator equation,which deems essential in our numerical *** overcome computational infeasability we use low rank hierarchical tensor product approximation/tree-based tensor formats,in particular tensor trains(TT tensors)and multi-polynomials,together with high-dimensional quadrature,*** controlling a destabilized version of viscous Burgers and a diffusion equation with unstable reaction term numerical evidence is given.

关键词： Feedback control Dynamic programming Hamilton-Jacobi-Bellman Tensor product approximation Variational Monte-Carlo

Electroactivity of the magnetotactic bacteria Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 103-110页

作者： mathias Fessler Qingxian Su Marlene Mark Jensen Yifeng Zhang Department of Environmental and Resource Engineering Technical University of DenmarkCopenhagenDK-2800Denmark

Magnetotactic bacteria reside in sediments and stratified water *** are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field ***,we show that two magnetotactic species,Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1,are *** *** and *** were able to generate current in microbial fuel cells with maximum power densities of 27 and 11μW/m^(2),*** the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite(Fe_(2)O_(3)).In addition,*** could reduce poorly crystalline iron oxide(FeOOH).Our study adds *** and *** to the growing list of known electroactive bacteria,and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

关键词： Magnetotactic bacteria Magnetospirillum magneticum Magnetospirillum gryphiswaldense Extracellular electron transfer Microbial fuel cells

Space aquatic chemistry:A roadmap for drinking water treatment in microgravity

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Environmental Science and Ecotechnology 2024年第3期19卷 26-28页

作者： Baiwen Ma Yaohui Bai Chengzhi Hu Beizhen Xie Junya Zhang mathias Ulbricht Libing Zheng Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China Lehrstuhl für Technische Chemie II Universität Duisburg-EssenEssen45117Germany Institute of Environmental Biology and Life Support Technology School of Biological Science and Medical EngineeringBeihang UniversityBeijing100191China Department of Water Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China Department of Isotope Biogeochemistry Helmholtz Centre for Environmental Research-UFZLeipzig04318Germany

Rapid advancement in aerospace technology has successfully enabled long-term life and economic activities in space,particularly in Low Earth Orbit(LEO),extending up to 2000 km from the mean sea ***,the sustainance of the LEO Economy and its Environmental Control and Life Support System(ECLSS)still relies on a regular cargo supply of essential commodities(e.g.,water,food)from Earth,for which there still is a lack of adequate and sustainable *** key challenge in this context is developing water treatment technologies and standards that can perform effectively under microgravity *** this technical challenge will be a milestone in providing a scientific basis and the necessary support mechanisms for establishing permanent bases in outer space and *** identify clues towards solving this challenge,we looked back at relevant scientific research exploring novel technologies and standards for deep space exploration,also considering feedback for enhancing these technologies on *** our findings,we share our outlook for the future of drinking water treatment in *** also bring up a new concept for space aquatic chemistry,considering the closed environment of engineered systems operating in microgravity.

关键词： Microgravity Drinking water treatment Water quality Challenges Strategies

Estimation of Daily Global Solar Radiation with Different Sunshine-Based Models for Some Burundian Stations

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Energy and Power Engineering 2024年第1期16卷 1-20页

作者： mathias Bashahu Gratien Ndacayisaba Department of Physics and Technology University of Burundi Bujumbura Burundi Department of Physics Ecole Normale Supérieure Bujumbura Burundi

Sunshine duration (S) based empirical equations have been employed in this study to estimate the daily global solar radiation on a horizontal surface (G) for six meteorological stations in Burundi. Those equations include the Ångström-Prescott linear model and four amongst its derivatives, i.e. logarithmic, exponential, power and quadratic functions. Monthly mean values of daily global solar radiation and sunshine duration data for a period of 20 to 23 years, from the Geographical Institute of Burundi (IGEBU), have been used. For any of the six stations, ten single or double linear regressions have been developed from the above-said five functions, to relate in terms of monthly mean values, the daily clearness index () to each of the next two kinds of relative sunshine duration (RSD): and . In those ratios, G0, S0 and stand for the extraterrestrial daily solar radiation on a horizontal surface, the day length and the modified day length taking into account the natural site’s horizon, respectively. According to the calculated mean values of the clearness index and the RSD, each station experiences a high number of fairly clear (or partially cloudy) days. Estimated values of the dependent variable (y) in each developed linear regression, have been compared to measured values in terms of the coefficients of correlation (R) and of determination (R2), the mean bias error (MBE), the root mean square error (RMSE) and the t-statistics. Mean values of these statistical indicators have been used to rank, according to decreasing performance level, firstly the ten developed equations per station on account of the overall six stations, secondly the six stations on account of the overall ten equations. Nevertheless, the obtained values of those indicators lay in the next ranges for all the developed sixty equations:;;;, with . These results lead to assert that any of the sixty developed linear regressions (and thus equations in terms of and ), fit

关键词： Clearness Index Two Kinds of Relative Sunshine Duration Ångström-Prescott Linear Model and Four Derivatives Statistical Tests Six Burundian Stations

Leisure-time physical activity and all-cause mortality and cardiovascular disease in adults with type 2 diabetes:Cross-country comparison of cohort studies

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Journal of Sport and Health Science 2024年第2期13卷 212-221页

作者： Jakob Tarp Mengyun Luo Miguel Adriano Sanchez-Lastra Knut Eirik Dalene Borja del Pozo Cruz mathias Ried-Larsen Reimar Wernich Thomsen Ulf Ekelund Ding Ding Department of Clinical Epidemiology Aarhus University&Aarhus University HospitalAarhus 8200Denmark Prevention Research Collaboration Sydney School of Public HealthThe University of SydneyCamperdownNSW 2006Australia Charles Perkins Centre the University of SydneyCamperdownNSW 2050Australia Department of Sports Medicine Norwegian School of Sports SciencesOslo 0806Norway Department of Special Didactics Faculty of Education and Sports SciencesUniversity of VigoPontevedra 36005Spain Well-Move Research Group Galicia Sur Health Research Institute(IIS Galicia Sur)SERGAS-UVIGOVigo 36213Spain Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0473Norway Centre for Active and Healthy Ageing Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdense 5230Denmark Faculty of Education University of CadizCadiz 11519Spain Biomedical Research and Innovation Institute of Cadiz(INiBICA)Research Unit Puerta del Mar University HospitalUniversity of CadizCadiz 11009Spain The Centre of Inflammation and Metabolism&the Centre for Physical Activity Research RigshospitaletUniversity of CopenhagenCopenhagen 2100Denmark Department of Sports Science and Clinical Biomechanics University of Southern DenmarkOdense 5230Denmark

Purpose:This study aimed to quantify the dose-response association and the minimal effective dose of leisure-time physical activity(PA)to prevent mortality and cardiovascular disease in adults with type 2 ***:Cross-country comparison of 2 prospective cohort studies including 14,913 and 17,457 population-based adults with type 2 diabetes from the UK and *** leisure-time PA was self-reported and categorized by metabolic equivalent hours per week(MET-h/week)according to World Health Organization recommendations:none,below recommendation(>0-7.49 MET-h/week);at recommended level(7.5-14.9 MET-h/week);above recommendation(>15 MET-h/week).Mortality and cardiovascular disease data were obtained from national ***:During a median follow-up of 12.4 and 9.7 years,in the UK and China cohorts,repectively,higher levels of leisure-time PA were inversely associated with all-cause(1571 and 2351 events)and cardiovascular mortality(392 and 1060 events),mostly consistent with a linear dose-response *** below,at,and above recommendations,compared with no activity,yielded all-cause mortality hazard ratios of0.94(95%confidence interval(95%CI):0.79-1.12),0.90(95%CI:0.74-1.10),and 0.85(95%CI:0.70-1.02)in British adults and 0.87(95%CI:0.68-1.10),0.88(95%CI:0.74-1.03),and 0.77(95%CI:0.70-0.85)in Chinese *** with cardiovascular mortality were more pronounced in British adults(0.80(95%CI:0.58-1.11),0.75(95%CI:0.52-1.09),and 0.69(95%CI:0.48-0.97))but less pronounced in Chinese adults(1.06(95%CI:0.76-1.47),1.01(95%CI:0.80-1.28),and 0.79(95%CI:0.69-0.92)).PA at recommended levels was not associated with lower rates of major adverse cardiovascular events(2345 and 4458 events).Conclusion:Leisure-time PA at the recommended levels was not convincingly associated with lower mortality and had no association with risk of major adverse cardiovascular events in British or Chinese adults with type 2 ***-time PA above current recom

关键词： Complications Epidemiology Exercise Prevention

Distortions in focusing laser pulses due to spatio-temporal couplings:an analytic description

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High Power Laser Science and Engineering 2024年第3期12卷 20-40页

作者： Klaus Steiniger Fabia Dietrich Daniel Albach Michael Bussmann Arie Irman Markus Loeser Richard Pausch Thomas Püschel Roland Sauerbrey Susanne Schöbel Ulrich Schramm mathias Siebold Karl Zeil Alexander Debus Helmholtz-Zentrum Dresden-Rossendorf DresdenGermany CASUS-Center for Advanced Systems Understanding GörlitzGermany Technische Universität Dresden DresdenGermany

In ultra-short laser pulses,small changes in dispersion properties before the final focusing mirror can lead to severe pulse distortions around the focus and therefore to very different pulse properties at the point of laser±matter interaction,yielding unexpected interaction *** mapping between far-and near-field laser properties intricately depends on the spatial and angular dispersion properties as well as the focal *** a focused Gaussian laser pulse under the influence of angular,spatial and group-delay dispersion,we derive analytical expressions for its pulse-front tilt,duration and width from a fully analytic expression for its electric field in the time±space domain obtained with scalar diffraction *** expression is not only valid in and near the focus but also along the entire propagation distance from the focusing mirror to the *** relating angular,spatial and group-delay dispersion before focusing at an off-axis parabola,where they are well measurable,to the respective values in the pulse’s focus are obtained by a ray tracing ***,these formulas are used to show in example setups that the pulse-front tilts of lasers with small initial dispersion can become several tens of degrees larger in the vicinity of the focus while being small directly in the *** formulas derived here provide the analytical foundation for observations previously made in numerical *** numerically simulating Gaussian pulse propagation and measuring properties of the pulse at distances several Rayleigh lengths off the focus,we verify the analytic expressions.

关键词： group-delay dispersion pulse-front tilt spatio-temporal couplings third-order dispersion ultra-short laser pulses

How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption

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Environmental Science and Ecotechnology 2024年第5期21卷 92-102页

作者： Qi Wang Oliver JLechtenfeld Luuk CRietveld Jonas Schuster mathias Ernst Roberta Hofman-Caris Jan Kaesler Chunmiao Wang Min Yang Jianwei Yu Frederik Zietzschmann Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of Sciences100085BeijingChina Delft University of Technology Department of Water ManagementPO Box 50482600GADelftthe Netherlands Department of Analytical Chemistry Research Group BioGeoOmicsHelmholtz Centre for Environmental ResearchUFZPermoserstr.1504318LeipzigGermany Berliner Wasserbetriebe LaboratoryMotardstr.3513629BerlinGermany Institute for Water Resources and Water Supply Hamburg University of TechnologyAm Schwarzenberg-Campus 321073HamburgGermany KWR Watercycle Research Institute 3433PENieuwegeinthe Netherlands ProVISCentre for Chemical Microscopy Helmholtz Centre for Environmental ResearchUFZPermoserstr.1504318LeipzigGermany Wageningen University and Research Department of Environmental TechnologyBornse Weilanden 96708 WGWageningenthe Netherlands University of Chinese Academy of Sciences 100049BeijingChina

Activated carbon is employed for the adsorption of organic micropollutants(OMPs)from water,typically present in concentrations ranging from ng L1 to mg L***,the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter(DOM),present at substantially higher concentrations in mg L*** the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural *** weight(MW),aromaticity,and polarity influence DOM *** the aromaticity-related metrics,such as UV254,of low MW DOM were proposed to correlate with DOM competitiveness,the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining DOM ***,we elucidate the intricate influence of aromaticity and polarity in low MW DOM competition,spanning from a fraction level to a compound level,by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fouriertransform ion cyclotron resonance mass *** exchange resin pre-treatment eliminated 93%of UV254-active DOM,predominantly aromatic and polar DOM,and only minimally alleviated DOM *** characterization revealed that nonpolar molecular formulas(constituting 26%PAC-adsorbable DOM)with medium aromaticity contributed more to the DOM *** analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by increased *** aromaticity-derived p-p interaction cannot facilitate the competitive adsorption of hydrophilic DOM *** results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for DOM *** a broader context,this study demonstrates an effect-oriented DOM analysis,elucidating counterbalancing interactions of DOM molecular properties

关键词： Activated carbon Organic micropollutants Dissolved organic matter(DOM) Multi-component adsorption Fourier-transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)

31 Plant Species against Blood Feeding and Disease Vectors Insects: Beyond Anti-Insect Properties, Unvalued Opportunities and Challenges for Health and Sustainability

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Pharmacology & Pharmacy 2024年第5期15卷 167-206页

作者： Prudence Bararunyeretse Jean Claude Niyokwizera Esperance Gateretse mathias Hitimana Research Center for Natural and Environmental Sciences (CRSNE) University of Burundi Bujumbura Burundi Institutes of Agronomic Sciences of Burundi (ISABU) Bujumbura Burundi East African Nutritional Sciences Institute (EANSI) University of Burundi Bujumbura Burundi

Plants with bioactive properties are greatly useful in preventing and controlling blood-sucking and disease-vector invertebrates, particularly in developing countries and low-income communities. Their application is a promising alternative to synthetic compounds whose use remains a health, environmental, and economic challenge. However, many are still unknown and unvalued, while others are becoming ignored and threatened. The main objective of this ethnobotanical study is to identify and characterize indigenous and locally grown plants against blood-sucking and disease-vector insects. Salient opportunities and challenges of using these plants are documented and discussed. Semi-structured interviews, using a prepared questionnaire, were conducted with 228 informants. The consensus index (CI) was calculated to analyze the reliability of the collected information. The identified 31 anti-insect plant species belong to 20 botanical families, four morphological categories, and six habitat types. They can be categorized as insecticidal plants (42% of the total), insect repellent (42% of the total), and both insecticidal and insect repellent (16% of the total). More than 54% of these are still abundant in the study area, while about 35.5% have become rare and difficultly accessible. Based on the numerical importance of related anti-insect plant species, the seven targeted blood-sucking insects range in the following decreasing order: Jiggers (16 species) > Fire Ants (9 species) > Flies (8 plants) > Mosquitoes (4 species) > Fleas (2 species) > Bedbugs (1 species) > lice (0 species). The three most commonly used plants, with the highest confirmation indices, are Tetradenia riparia (ICs = 0.712), Eucalyptus globulus subsp. maidenii (ICs = 0.302), and Solanum aculeastrum (ICs = 0.288). The antimicrobial role of many locally grown anti-insect plants and the multiple other associated valorization possibilities are ignored by most informants. Domesticating, propagating, protecting

关键词： Blood-Feeding Insects Anti-Insect Plants Biopesticides Sustainability Burundi

Unsuccessful tuberculosis treatment outcomes across Brazil's geographical landscape before and during the COVID-19 pandemic:are we truly advancing toward the sustainable development/end TB goal?

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Infectious Diseases of Poverty 2024年第1期13卷 105-106页

作者： Reginaldo Bazon Vaz Tavares Thais Zamboni Berra Yan mathias Alves Marcela Antunes Paschoal Popolin Antonio Carlos Vieira Ramos Ariela Fehr Tartaro Clara Ferreira de Souza Ricardo Alexandre Arcencic Department of Maternal-Infant and Public Health Nursing University of São Paulo at Ribeirão Preto College of Nursing (USP/RPCN) Ribeirão Preto São Paulo Brazil Federal University of Tocantins Palmas Campus (FUT) Palmas Brazil State University of Minas Gerais Passos Campus (SUMG) Passos Brazil

Background Tuberculosis is one of the most significant infectious diseases for global public *** reallocation of healthcare resources and the restrictions imposed by the COVID-19 pandemic have hindered access to TB diag-nosis and *** in unfavorable outcomes of the disease have been observed in *** objective of this study was to analyze the spatial distribution of unfavorable TB treatment outcomes in Brazil before and during the *** An ecological study with spatial analysis was conducted with all 5569 municipalities in *** reported cases of tuberculosis between January 2010 and December 2021,as well as reported cases of COVID-19 from Febru-ary 2020 to December 2021,were *** outcomes studied encompass loss to follow-up,drug-resistant tuber-culosis,and *** Getis Ord GI*technique was employed to assess spatial association,and the Kernel density estimator was used to identify areas with concentrated increases or decreases in *** Local Moran's/was used to examine the spatial association between outcomes and cOVID-19 *** study was approved by the Research Ethics Committee of Ribeirao Preto Nursing School,University of Sao *** There were 134,394 cases of loss to follow-up,10,270 cases of drug resistance,and 37,863 *** of high and low values were identified for all three outcomes,indicating significant changes in the spatial distribu-tion *** in concentrations were observed for lost to follow-up cases in the Southeast,while reductions occurred in the Northeast,South,and ***-resistant tuberculosis experienced an increase in the Southern and Southeastern regions and a decrease in the Northeast and ***-related deaths showed notable concentra-tions in the Midwest,Northeast,South,and *** was an increase in high occurrence clusters for deaths after 2020 and 2021 in the *** The pandemic has brought additional chal

关键词： Tuberculosis COVID-19 Spatial analysis Ecological studies