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Pseudo-orthogonality for graph 1-Laplacian eigenvectors and applications to higher Cheeger constants and data clustering

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Frontiers of Mathematics in China 2022年第4期17卷 591-623页

作者： antonio Corbo ESPOSITO Gianpaolo PISCITELLI Dipartimento di Ingegneria Elettrica e dell’Informazione“M.Scarano” Universitàdegli Studi di Cassino e del Lazio MeridionaleVia G.Di Biasio n.4303043Cassino(FR)Italy

The data clustering problem consists in dividing a data set into prescribed groups of homogeneous *** is an NP-hard problem that can be relaxed in the spectral graph theory,where the optimal cuts of a graph are related to the eigenvalues of graph *** this paper,we first give new notations to describe the paths,among critical eigenvectors of the graph 1-Laplacian,realizing sets with prescribed *** introduce the pseudo-orthogonality to characterize m_(3)(G),a special eigenvalue for the graph ***,we use it to give an upper bound for the third graph Cheeger constant h_(3)(G),that is,h_(3)(G)≤m_(3)(G).This is a first step for proving that the k-th Cheeger constant is the minimum of the 1-Laplacian Raylegh quotient among vectors that are pseudo-orthogonal to the vectors realizing the previous k−1 Cheeger ***,we apply these results to give a method and a numerical algorithm to compute m3(G),based on a generalized inverse power method.

关键词： Graph 1-Laplacian graph Cheeger constants pseudo-orthogonality critical values data clustering

Short-term effects of post-fire mulching with straw or wood chips on soil properties of semi-arid forests

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林业研究:英文版 2023年第6期34卷 1777-1790页

作者： Manuel Esteban Lucas Borja Demetrio antonio Zema Department of Agroforestry Technology Science and GeneticsSchool of Advanced Agricultural and Forestry EngineeringCampus Universitario s/nCastilla La Mancha UniversityE-02071 Castilla La ManchaAlbaceteSpain Department AGRARIA “Mediterranea”University of Reggio CalabriaLocalitàFeo di VitoI-89122 Reggio CalabriaItaly

Few studies have compared the variability of soil properties using different types of mulches in semi-arid *** study evaluated the changes in physico-chemical soil properties in a semi-arid forest of Central Eastern Spain,where straw and pine wood chips were distributed as mulch three months after a *** were sampled under burned and unmulched and burned and mulched plots three and nine months after the *** data was processed using Principal Component Analysis(PCA)and Analytical Hierarchical Cluster Analysis(AHCA).Mulching with straw or wood chips did not have any significant effects on the texture and chemical properties of burned sites few months after the *** contrast,significant changes are expected over time in organic matter,nutrients and many *** were no significant differences in soil properties between the two *** low changes were confirmed by PCA coupled with AHCA,which did not show a clear distinction among the three soil ***,a noticeable and significant variability of many of these properties over time was *** study shows that mulching does not degrade of soil properties in the short-term after a wildfire and after post-fire treatments,and thus helps protect semi-arid forest ecosystems against the negative impacts of high-severity fires.

关键词： Post-fire management High-severity fire Aridisols Erosion Vegetal residues incorporation Soil degradation

Comparative Study of Slope Soils Analysis by Using Limit Equilibrium and Finite Element Methods

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International Journal of Geosciences 2022年第12期13卷 1089-1102页

作者： Kempena Adolphe Watha Ndoudy Noël Obami Ondon Harmel Mbilou Urbain Gampio antonio Olimpio Gonçalves Rafael guardado Lacaba Boudzoumou Florent Department of Geology Faculty of Sciences and Techniques Marien Ngouabi University Brazzaville Republic of Congo Mechanical Energy and Engineering Laboratory Higher National Polytechnic School Marien Ngouabi University Brazzaville Republic of Congo Department of Geology Faculty of Sciences Agostinho Neto University Luanda Angola Department of Geology Faculty of Mines and Geology Higher Institute of Mines and Metallurgy Moa Cuba

The slope soil analysis remains a corporate concern in construction activities. Because of its significance, the evaluation of slope soil stability has called widespread attention to several researchers all over the world. Many methods have been technologically advanced to evaluate the stability of slopes soils founded on distinct expectations and circumstances. Every method has specific benefits and limits. This work makes a comparison among safety factors and slip surfaces of slopes soils based on using Limit Equilibrium and Finite Element methods. Therefore, SLIDE 6.0 and PLAXIS 8.0 software were used for Limit Equilibrium and Finite Element methods, respectively. The computations of safety factors were performed for diverse shapes of slopes including different types of soils. Failure surfaces and values of safety factors obtained were compared for both methods used. It was noticed that the safety factors obtained from Limit Equilibrium methods were larger than of which is obtained by the finite element code. Moreover, an important change is noticed between the slip surfaces obtained by using both approaches.

关键词： Slopes Soils Slip Surface Limit Equilibrium Finite Element Factor of Safety

Branched chain amino acids in hepatic encephalopathy and sarcopenia in liver cirrhosis:Evidence and uncertainties

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World Journal of Gastroenterology 2023年第19期29卷 2905-2915页

作者： Giuseppe Marrone Amato Serra Luca Miele Marco Biolato antonio Liguori antonio Grieco antonio Gasbarrini Medical and Surgical Sciences Fondazione Policlinico Universitario A.Gemelli-IRCCSUniversita Cattolica del Sacro CuoreRome 00168Italy

Liver cirrhosis is commonly associated with nutritional alterations,reported in 20% of patients with compensated disease and over 60% of patients with decompensated *** disturbances are associated with a worse prognosis and increased risk of *** levels of branched-chain amino acids(BCAAs)are decreased in patients with liver *** imbalance of amino acids levels has been suggested to be associated with the development of complications,such as hepatic encephalopathy and sarcopenia,and to affect the clinical presentation and prognosis of these *** studies investigated the efficacy of BCAAs supplementation as a therapeutic option in liver cirrhosis,but uncertainties remain about the real efficacy,the best route of administration,and dosage.

关键词： Branched-chain amino acids Hepatic encephalopathy Sarcopenia Liver cirrhosis

ARHCS (Automatic Rainfall Half-Life Cluster System): A Landslides Early Warning System (LEWS) Using Cluster Analysis and Automatic Threshold Definition

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International Journal of Geosciences 2024年第1期15卷 54-69页

作者： Cassiano antonio Bortolozo Luana Albertani Pampuch Marcio Roberto Magalhães De Andrade Daniel Metodiev Adenilson Roberto Carvalho Tatiana Sussel Gonçalves Mendes Tristan Pryer Harideva Marturano Egas Rodolfo Moreda Mendes Isadora Araújo Sousa Jenny Power Cemaden - National Center for Monitoring and Early Warning of Natural Disasters General Coordination of Research and Development S&#227o José dos Campos Brazil Environmental Engineering Department Institute of Science and Technology S&#227o Paulo State University S&#227o José dos Campos Brazil Department of Mathematical Sciences University of Bath Bath UK Institute for Mathematical Innovation University of Bath Bath UK

A significant portion of Landslide Early Warning Systems (LEWS) relies on the definition of operational thresholds and the monitoring of cumulative rainfall for alert issuance. These thresholds can be obtained in various ways, but most often they are based on previous landslide data. This approach introduces several limitations. For instance, there is a requirement for the location to have been previously monitored in some way to have this type of information recorded. Another significant limitation is the need for information regarding the location and timing of incidents. Despite the current ease of obtaining location information (GPS, drone images, etc.), the timing of the event remains challenging to ascertain for a considerable portion of landslide data. Concerning rainfall monitoring, there are multiple ways to consider it, for instance, examining accumulations over various intervals (1 h, 6 h, 24 h, 72 h), as well as in the calculation of effective rainfall, which represents the precipitation that actually infiltrates the soil. However, in the vast majority of cases, both the thresholds and the rain monitoring approach are defined manually and subjectively, relying on the operators’ experience. This makes the process labor-intensive and time-consuming, hindering the establishment of a truly standardized and rapidly scalable methodology on a large scale. In this work, we propose a Landslides Early Warning System (LEWS) based on the concept of rainfall half-life and the determination of thresholds using Cluster Analysis and data inversion. The system is designed to be applied in extensive monitoring networks, such as the one utilized by Cemaden, Brazil’s National Center for Monitoring and Early Warning of Natural Disasters.

关键词： Landslides Early Warning System (LEWS) Cluster Analysis Landslides Brazil

Synthesis of Lignin-Based Polyacid in an Acidic Ionic Liquid: A Green Method to Improve the Performance of Lignin as Catalyst in Urea-Formaldehyde Resin

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Journal of Renewable Materials 2022年第2期10卷 237-246页

作者： Hamed Younesi-Kordkheili antonio Pizzi Department of Wood and Paper Sciences Faculty of Natural ResourcesSemnan UniversitySemnanIran LERMAB University of LorraineEpinalFrance

The aim of this research was to investigate the effect of ionic liquid treated lignin-based polyacid as a catalyst for urea-formaldehyde(UF)*** of lignin was carried out,without any catalyst,with anhydride maleic and 1-butyl-3-methylimidazolium hydrogen sulfate[Bmim][HSO 4]as acidic ionic liquid to form maleated lignin-based polyacids(MA-IL).The performance of MA-IL as UF resin catalyst was respectively compared to hyroxymethylated lignin-based polyacid(MA-HL)and to NH 4 *** FTIR analysis indicated that the propor-tion of-COOH and C-O bonds increased due to the esterification of lignin with ionic liquid rather than its *** tests indicated that the gelation time of the UF resin was shorter by adding MA-IL when compared to NH 4 Cl and MA-HL,*** analysis showed that the addition of MA-IL significantly decreased the temperature peak(Tp)of the UF resin;as the Tp of the UF resin with 2 wt%MA-IL was lower than with MA-HL and NH 4 Cl,*** panel test results of plywood bonded with a UF resin with a MA-IL level increasing from 1%to 3%,effectively improved the mechanical strength,water resistance and formaldehyde emission even higher than with MA-HL and NH 4 Cl,respectively.

关键词： Lignin-based polyacid maleic anhydride ionic liquid esterification plywood

A Weighted Average Consensus Approach for Decentralized Federated Learning

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Machine Intelligence Research 2022年第4期19卷 319-330页

作者： Alessandro Giuseppi Sabato Manfredi antonio Pietrabissa Department of Computer Controland Management EngineeringUniversity of Rome La SapienzaRome 00185Italy Department of Electrical Engineering and Information Technology University of Naples Federico ⅡNaples 80125Italy

Federated learning(FedL)is a machine learning(ML)technique utilized to train deep neural networks(DeepNNs)in a distributed way without the need to share data among the federated training *** was proposed for edge computing and Internet of things(IoT)tasks in which a centralized server was responsible for coordinating and governing the training *** remove the design limitation implied by the centralized entity,this work proposes two different solutions to decentralize existing FedL algorithms,enabling the application of FedL on networks with arbitrary communication topologies,and thus extending the domain of application of FedL to more complex scenarios and new *** the two proposed algorithms,one,called FedLCon,is developed based on results from discrete-time weighted average consensus theory and is able to reconstruct the performances of the standard centralized FedL solutions,as also shown by the reported validation tests.

关键词： Federated learning(FedL) deep learning federated averaging(FedAvg) machine learning(ML) artificial intelligence discrete-time consensus distributed systems.

Glial regenerative response in the imaginal discs of Drosophila melanogaster

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Neural Regeneration Research 2023年第1期18卷 109-110页

作者： Sergio B.Velarde antonio Baonza Centro de Biología Molecular“Severo Ochoa” CSIC/UAMMadridSpain

Glial cells play a key role during nervous system development and actively participate in all the cellular processes involved in maintaining its structural robustness and functional *** response to neuronal damage,glial cells proliferate,migrate to the injured region and change their morphology,function,and behavior(Gallo and Deneen,2014;Kato et al.,2018).This glial regenerative response is associated with the repairing function of these cells and is found across species,suggesting that it may reflect a common underlying genetic mechanism(Kato et al.,2018).

关键词： damage migrate

Hyperglycemia in acute ischemic stroke: physiopathological and therapeutic complexity

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Neural Regeneration Research 2022年第2期17卷 292-299页

作者： Federica Ferrari antonio Moretti Roberto Federico Villa Department of Biology and Biotechnology Laboratory of Pharmacology and Molecular Medicine of Central Nervous SystemUniversity of PaviaVia FerrataPaviaItaly

Diabetes mellitus and associated chronic hyperglycemia enhance the risk of acute ischemic stroke and lead to worsened clinical outcome and increased mortality. However, post-stroke hyperglycemia is also present in a number of non-diabetic patients after acute ischemic stroke, presumably as a stress response. The aim of this review is to summarize the main effects of hyperglycemia when associated to ischemic injury in acute stroke patients, highlighting the clinical and neurological outcomes in these conditions and after the administration of the currently approved pharmacological treatment, i.e. insulin. The disappointing results of the clinical trials on insulin(including the hypoglycemic events) demand a change of strategy based on more focused therapies. Starting from the comprehensive evaluation of the physiopathological alterations occurring in the ischemic brain during hyperglycemic conditions, the effects of various classes of glucose-lowering drugs are reviewed, such as glucose-like peptide-1 receptor agonists, DPP-4 inhibitors and sodium glucose cotransporter 2 inhibitors, in the perspective of overcoming the up-to-date limitations and of evaluating the effectiveness of new potential therapeutic strategies.

关键词： acute ischemic stroke diabetes mellitus DPP-4 inhibitor glucose-like peptide-1 receptor agonist hyperglycemia hypoglycemia insulin physiopathology sodium glucose cotransporter 2 inhibitor