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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

A Dynamic Network Game of the Fintech Industry

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Journal of the Operations Research Society of China 2024年第1期12卷 5-33页

作者： David W.K.Yeung leon A.Petrosyan Ying-Xuan Zhang SRS Consortium for Advanced Study in Cooperative Dynamic Games Shue Yan UniversityHong KongChina Center of Game Theory St Petersburg State UniversitySaint PetersburgRussia Department of Finance Asia UniversityTaichung CityTaiwanChina Faculty of Applied Mathematics-Control Processes and Center of Game Theory St Petersburg StateUniversitySaint PetersburgRussia

Economies of scale,economies of scope,and technology spillover are decisive eco-nomic elements that are crucial to the development in the Fintech *** externalities are often realized through network *** this paper,we presenta dynamic network ofﬁnancialﬁrms which exhibits these decisive *** game equilibria are characterized.A Pareto efﬁcient solution involving col-laboration of allﬁrms is *** obtain a fair-share distribution of cooperativegains,the Shapley value is adopted as the sharing *** distributionmechanisms which guarantee the fulﬁlment of the Shapley value distribution in eachstage of the cooperation duration are derived.

关键词： Network game Network equilibria Shapley value Pareto efﬁcientcooperation

A CFD Model to Evaluate Near-Surface Oil Spill from a Broken Loading Pipe in Shallow Coastal Waters

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Fluid Dynamics & Materials Processing 2024年第1期20卷 59-77页

作者： Portia Felix Lee leon Derek Gay Stefano Salon Hazi Azamathulla Department of Civil and Environmental Engineering The University of the West IndiesSt.AugustineTrinidad and Tobago National Institute of Oceanography and Experimental Geophysics-OGS TriesteItaly

Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social *** is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located *** study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water *** results show that the spill overall profile is articulated in three major flow *** first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill *** behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the *** Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.

关键词： CFD model Navier-Stokes equations projection method water surface oil spill shallow coastal waters

Speed and surface steepness affect internal tibial loading during running

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Journal of Sport and Health Science 2024年第1期13卷 118-124页

作者： Hannah Rice Markus Kurz Patrick Mai leon Robertz Kevin Bill Timothy R.Derrick Steffen Willwacher Department of Physical Performance Norwegian School of Sport SciencesOslo 0806Norway Sports Tech Research Centre Mid Sweden UniversityÖstersund SE-83125Sweden Department of Mechanical and Process Engineering Offenburg University of Applied SciencesOffenburg 77652Germany Institute of Biomechanics and Orthopaedics German Sport University CologneCologne 50933Germany Department of Kinesiology Iowa State UniversityAmesIA 50011USA

Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress *** encounter varied surface steepness(gradients)when running outdoors and may adapt their speed according to the *** study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different ***:Twenty recreational runners ran on a treadmill at 3 different speeds(2.5 m/s,3.0 m/s,and 3.5 m/s)and gradients(level:0%;uphill:+5%,+10%,and+15%;downhill:-5%,-10%,and-15%).Force and marker data were collected synchronously *** moments were estimated at the distal third centroid of the tibia about the medial-lateral axis by ensuring static equilibrium at each 1%of *** was derived from bending moments at the anterior and posterior peripheries by modeling the tibia as a hollow ***-way repeated-measures analysis of variance were conducted using both functional and discrete statistical ***:There were significant main effects for running speed and gradient on peak bending moments and peak anterior and posterior *** running speeds resulted in greater tibial *** uphill at+10%and+15%resulted in greater tibial loading than level *** downhill at-10%and-15%resulted in reduced tibial loading compared to level *** was no difference between+5%or-5%and level ***:Running at faster speeds and uphill on gradients≥+10%increased internal tibial loading,whereas slower running and downhill running on gradients≥-10%reduced internal *** running speed according to the gradient could be a protective mechanism,providing runners with a strategy to minimize the risk of tibial stress injuries.

关键词： Bending moments Gradient Musculoskeletal modeling Overuse injury Tibial stress Training factors

Origin and diversification of maize: Two teosintes but different contributions

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Molecular Plant 2024年第2期17卷 233-235页

作者： Jonathan Acosta-Bayona Gloria leon-Martinez Jean-Philippe Vielle-Calzada Grupo de Desarrollo Reproductivo y Apomixis UGA Laboratorio Nacional de Genomica para la BiodiversidadCinvestav IrapuatoIrapuato Gto CP36825Mexico

The unique topographic,climatic,and latitudinal heterogeneity of Mesoamerica is crucial to understanding the evolutionary emergence of one of the richest cultural and biological regions in the planet and its impact on food *** divided between two regions of large biodiversity-lowland tropical or coastal zones and temperate or subtropical highlands sculpted by parallel sierras and their central plateau-the Mexican territory harbors more than 2000 endemic monocotyledonous species,including several hundred grasses(Poaceae),particularly those belonging to the genus Zea,composed of maize(Zea mays ***)and its wild relatives,collectively referred as teosintes.

关键词： collective planet harbor

Organochlorides Mediate Oxidation Reactions Induced by Low Dose Ionizing Radiation

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CCS Chemistry 2024年第7期6卷 1712-1720页

作者： Juncheng Liu Tobias G.Brevé Bing Xu Peter-leon Hagedoorn Antonia G.Denkova Rienk Eelkema Department of Radiation Science and Technology Delft University of Technology2629 JB Delft Department of Chemical Engineering Delft University of Technology2629 HZ Delft Department of Biotechnology Delft University of Technology2629 HZ Delft

The controlled release of drugs using local ionizing radiation presents a promising approach for targeted cancer treatment,particularly when applied in concurrent *** these approaches,radiation-generated reactive species often play an important ***,the reactive species that can be used to trigger release have low yield and lack ***,we demonstrate the generation of highly oxidative species when aqueous solutions containing low concentrations of organochlorides(such as chloroform)are irradiated with ionizing radiation at therapeutically relevant *** reactive species were identified as peroxyl radicals,which formed in a reaction cascade between organochlorides and aqueous *** employed stilbene-based probes to investigate the oxidation process,showing double bond oxidation and *** translate this reactivity into a radiation-sensitive material,we synthesized a micelle-forming amphiphilic block copolymer that has stilbene as the linker between two *** exposure to ionizing radiation,the oxidation of stilbene led to the cleavage of the polymer,which induces the dissociation of the block-copolymer micelles and the release of loaded drugs.

关键词： drug delivery micelles radiation chemistry reactive oxygen species ionizing radiation reaction mechanisms

Sodium-glucose cotransporter-2 inhibitors protect tissues via cellular and mitochondrial pathways:Experimental and clinical evidence

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World Journal of Experimental Medicine 2024年第2期14卷 46-52页

作者： Raúl Lelio Sanz Sebastián García Menéndez Felipe Inserra leon Ferder Walter Manucha Department of Pathology Facultad de Ciencias MédicasUniversidad Nacional de CuyoMendoza 5500Argentina Department of Pharmacology Instituto de Medicina y Biología Experimental de CuyoCentro Científico TecnológicoMendoza 5500Argentina Department of Nephrology Universidad de MaimónidesCiudad Autónoma de Buenos Aires C1405Argentina Department of Cardiology Universidad de MaimónidesCiudad Autónoma de Buenos Aires C1405Argentina

Mitochondrial dysfunction is a key driver of cardiovascular disease(CVD)in metabolic syndrome and *** dysfunction promotes the production of reactive oxygen species(ROS),which cause oxidative stress and *** II,the main mediator of the renin-angiotensin-aldosterone system,also contributes to CVD by promoting ROS *** activity of sirtuins(SIRTs),a family of proteins that regulate cellular metabolism,also worsens oxidative *** of energy production by mitochondria is a common feature of all metabolic *** SIRT levels and 5’adenosine monophosphate-activated protein kinase signaling stimulate hypoxia-inducible factor 1 beta,which promotes ***,in turn,increases autophagy and mitophagy,processes that clear cells of debris and protect against *** cotransporter-2 inhibitors(SGLT2i),a class of drugs used to treat type 2 diabetes,have a beneficial effect on these *** clinical trials have shown that SGLT2i improves cardiac function and reduces the rate of cardiovascular and renal ***2i also increase mitochondrial efficiency,reduce oxidative stress and inflammation,and strengthen *** findings suggest that SGLT2i hold great potential for the treatment of ***,they are proposed as anti-aging drugs;however,rigorous research is needed to validate these preliminary findings.

关键词： Sodium-glucose cotransporter-2 inhibitors Cardiovascular diseases Sirtuins Oxidative stress Inflammation Mitochondrial dysfunction

Impacts of brood parasitism by shiny cowbird Molothrus bonariensis on the breeding success of a small host, the black-backed water tyrant Fluvicola albiventer

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Current Zoology 2024年第4期70卷 539-547页

作者： Lorena Vanesa Sovrano Evelina Jesica leon Rodrigo Ezequiel Lorenzón Pamela Fernanda Olguin Adolfo Héctor Beltzer Alejandro Raúl Giraudo Laboratorio de Biodiversidad y Conservacion de Tetrapodos Instituto Nacional de Limnologia(INALICONICET-UNL)Paraje El Pozo s/nSanta Fe(3000)Argentina Departamento de Biologia Universidad Autonoma de Entre RiosKm 10.5 RP 11Oro Verde(3100)Entre RiosArgentina Departamento de Biologia Universidad Nacional del LitoralFacultad de Humanidades y CienciasParaje Ei Pozo s/nSanta Fe(3000)Argentina

The shiny cowbird Molothrus bonariensis parasitizes many species with different life-history traits and has a detrimental effect on the survival of the progeny of the *** response,hosts have developed numerous antiparasitic ***,we examined the effects of brood parasitism by shiny cowbird on the clutch and brood sizes(83 nests)in a small host,the black-backed water tyrant Fluvicola *** also studied whether the death of parasite nestlings was related to the care of the foster parents and whether the host had any antiparasitic defense against the shiny *** results indicate that brood parasitism significantly decreased the host hatching and fledging *** majority of nest failures(57%)were caused by brood *** cowbird parasitism occurred in 52%of nests and the intensity of parasitism was 1.23±0.53 eggs per parasitized *** the total host eggs,54%were *** the incubation stage,20 nests(47%)were abandoned because of egg punctures by shiny cowbirds *** two parasitic fledglings were recorded,while the remaining nestlings either died from starvation(n=12)or predation(n=3).Foster parents abandoned parasitic nestlings between 5 and 10 days *** findings demonstrate that the shiny cowbird has very low rates of fledging success when parasitizing black-backed water ***,parasitism had a high reproductive cost in the black-backed water tyrant because a very low proportion(7%)of the parasitized nests(n=43)were successful.

关键词： brood parasitism host defenses nest desertion shiny cowbird small host.

Gate-controlled supercurrent effect in dry-etched Dayem bridges of non-centrosymmetric niobium rhenium

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Nano Research 2024年第7期17卷 6575-6581页

作者： Jennifer Koch Carla Cirillo Sebastiano Battisti leon Ruf Zahra Makhdoumi Kakhaki Alessandro Paghi Armen Gulian Serafim Teknowijoyo Giorgio De Simoni Francesco Giazotto Carmine Attanasio Elke Scheer Angelo Di Bernardo Department of Physics University of KonstanzUniversitätsstraße 1078464 KonstanzGermany CNR-Spin c/o Universitàdegli Studi di Salernovia Giovanni Paolo II 13284084 Fisciano(SA)Italy NEST Istituto Nanoscienze-CNR and Scuola Normale SuperiorePiazza San Silvestro 1256127 PisaItaly Dipartimento di Fisica“E.R.Caianiello” Universitàdegli Studi di SalernoVia Giovanni Paolo II 13284084 Fisciano(SA)Italy Advanced Physics Laboratory Institute for Quantum StudiesChapman UniversityBurtonsvilleMD 20866USA

The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction,named as gate-controlled supercurrent(GCS),has raised great interest for fundamental and technological *** gain a deeper understanding of this effect and develop superconducting technologies based on it,the material and physical parameters crucial for the GCS effect must be ***-down fabrication protocols should also be optimized to increase device scalability,although studies suggest that top-down fabricated devices are more resilient to show a ***,we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of the noncentrosymmetric superconductor niobium rhenium with varying ratios of the constituents(NbRe).Unlike other devices previously reported and made with a top-down approach,our NbRe devices systematically exhibit a GCS effect when they were fabricated from NbRe thin films with small grain size and etched in specific *** observations pave the way for the realization of top-down-made GCS devices with high *** results also imply that physical parameters like structural disorder and surface physical properties of the nanobridges,which can be in turn modified by the fabrication process,are crucial for a GCS observation,providing therefore also important insights into the physics underlying the GCS effect.

关键词： superconductivity non-centrosymmetric superconductors superconducting devices gated devices gate-controlled supercurrent top-down fabrication