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SRMD:Sparse Random Mode Decomposition

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Communications on Applied Mathematics and Computation 2024年第2期6卷 879-906页

作者： Nicholas richardson Hayden Schaeffer Giang Tran University of Waterloo WaterlooONCanada University of British Columbia VancouverBCCanada University of California Los AngelesCAUSA

Signal decomposition and multiscale signal analysis provide many useful tools for timefrequency *** proposed a random feature method for analyzing time-series data by constructing a sparse approximation to the *** randomization is both in the time window locations and the frequency sampling,which lowers the overall sampling and computational *** sparsification of the spectrogram leads to a sharp separation between time-frequency clusters which makes it easier to identify intrinsic modes,and thus leads to a new data-driven mode *** applications include signal representation,outlier removal,and mode *** benchmark tests,we show that our approach outperforms other state-of-the-art decomposition methods.

关键词： Sparse random features Signal decomposition Short-time Fourier transform

How do neurons age?A focused review on the aging of the microtubular cytoskeleton

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Neural Regeneration Research 2024年第9期19卷 1899-1907页

作者： Brad richardson Thomas Goedert Shmma Quraishe Katrin Deinhardt Amritpal Mudher School of Biological Sciences University of SouthamptonSouthamptonUK Institute of Developmental and Regenerative Medicine University of OxfordOxfordUK

Aging is the leading risk factor for Alzheimer’s disease and other neurodegenerative diseases. We now understand that a breakdown in the neuronal cytoskeleton, mainly underpinned by protein modifications leading to the destabilization of microtubules, is central to the pathogenesis of Alzheimer’s disease. This is accompanied by morphological defects across the somatodendritic compartment, axon, and synapse. However, knowledge of what occurs to the microtubule cytoskeleton and morphology of the neuron during physiological aging is comparatively poor. Several recent studies have suggested that there is an age-related increase in the phosphorylation of the key microtubule stabilizing protein tau, a modification, which is known to destabilize the cytoskeleton in Alzheimer’s disease. This indicates that the cytoskeleton and potentially other neuronal structures reliant on the cytoskeleton become functionally compromised during normal physiological aging. The current literature shows age-related reductions in synaptic spine density and shifts in synaptic spine conformation which might explain age-related synaptic functional deficits. However, knowledge of what occurs to the microtubular and actin cytoskeleton, with increasing age is extremely limited. When considering the somatodendritic compartment, a regression in dendrites and loss of dendritic length and volume is reported whilst a reduction in soma volume/size is often seen. However, research into cytoskeletal change is limited to a handful of studies demonstrating reductions in and mislocalizations of microtubule-associated proteins with just one study directly exploring the integrity of the microtubules. In the axon, an increase in axonal diameter and age-related appearance of swellings is reported but like the dendrites, just one study investigates the microtubules directly with others reporting loss or mislocalization of microtubule-associated proteins. Though these are the general trends reported, there are clea

关键词： age-related changes aging cytoskeleton microtubules neuronal morphology

How to fill the biodiversity data gap:Is it better to invest in fieldwork or curation?

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Plant Diversity 2024年第1期46卷 39-48页

作者： Carlos A.Vargas Marius Bottin Tiina Sarkinen James E.richardson Marcela Celis Boris Villanueva Adriana Sanchez Programa de Biología Facultad de Ciencias NaturalesUniversidad del RosarioBogotaD.C.Colombia Subdireccion Científica Jardín Botanico de Bogota“Jose Celestino Mutis”BogotaD.C.Colombia Independent Researcher BogotaD.C.Colombia Tropical Diversity Section Royal Botanic Garden EdinburghUK School of Biological Earth and Environmental SciencesUniversity College CorkCorkIreland Departamento de Química y Biología Universidad del NorteKm.5 Vía Puerto ColombiaArea Metropolitana de Barranquilla 081007Colombia

Data gaps and biases are two important issues that affect the quality of biodiversity information and downstream *** how best to fill existing gaps and account for biases is necessary to improve our current information most *** current main approaches for obtaining and improving data include(1)curation of biological collections,and(2)***,the comparative effectiveness of these approaches in improving biodiversity data remains little *** used the Flora de Bogota project to study the magnitude of change in species richness,spatial coverage,and sample coverage of plant records based on curation versus *** process of curation resulted in a decrease in species richness(synonym and error removal),but it significantly increased the number of records per *** contributed to a slight increase in species richness,via accumulation of new ***,curation led to increases in spatial coverage,species observed by locality,the number of plant records by species,and localities by species compared to ***,curationwas more efficient in producing new information compared to fieldwork,mainly because of the large number of records available in *** recommend intensive curatorial work as the first step in increasing biodiversity data quality and quantity,to identify bias and gaps at the regional scale that can then be targeted with *** stepwise strategy would enable fieldwork to be planned more costeffectively given the limited resources for biodiversity exploration and characterization.

关键词： Colombia Flora de Bogota Sample coverage Species richness Tropical Andes

Assessment of CO_(2)storage prospect based on physical properties of Rio Bonito Formation rock units

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Energy Geoscience 2024年第1期5卷 321-330页

作者： richardson M.Abraham-A Stephanie San Martín Cañas Isabella F.S.Miranda Colombo C.G.Tassinari Institute of Energy and Environment(IEE) University of São Paulo(USP)Brazil Research Centre for Greenhouse Gas Innovation(RCGI) University of Sãao Paulo(USP)Brazil

The physical properties of the rock units associated with the Rio Bonito Formation are presented in this study with the focus on modelling reservoir quality based on petrophysics-derived parameters to evaluate CO_(2)storage *** involves the modelling of the reservoir depths,thicknesses,flow zone indicators(FZI),and effective permeability(Keff)and presenting the CO_(2)storage efficiency factors peculiar to the rock units of the study *** results presented by this study for the stated objectives are not quite common in the *** values range from 200 mD to higher than 2000 mD,and FZI values are generally above 1.0 mm and up to 13.0 mm within the portions covered by the drilled *** sandstone units recorded are up to 20 m thick in some *** Keff and FZI models indicate the sandstone reservoirs as permeable units to support the injection and circulation of CO_(2)within the potential reservoir units of the Rio Bonio Formation across São Paulo *** from some points in the southeastern part of the study location,where the Rio Bonito are delineated at depths less than 800 m(minimum CO_(2)storage depth based on best practices),other portions are deeper,ranging from 950 m to 3500 ***-bedded layers will affect the integrity of the rocks as CO_(2)storage tanks or reservoir seals/traps/overburden within the *** bed thicknesses are up to 20 m in some ***,hybrid CO_(2)reservoir units are feasible,especially in portions where thin siltstone layers are sandwiched between sandstone units to provide considerable thicknesses based on CO_(2)storage *** current study shows that useable areas considering reservoir thickness,depth,and other physical qualities will significantly control the CO_(2)storage efficiency of the study *** studies featuring a detailed geophysical exploration of the site to confirm the availability and saturations of preexisting fluid(hydrocarbon and water)are encouraged

关键词： Rio Bonito Effective permeability Fluid transmissibility CO_(2)storage prospect Reservoir quality Overburden integrity Flow zones

Tuning electronic properties of cobalt phthalocyanines for oxygen reduction and evolution reactions

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Science China Chemistry 2024年第1期67卷 398-407页

作者： Jianlin Jiang Zhen Liu Shuaijun Pan Xinnian Xia Bing Qin Yang Hu Xuxu Wang Jiamin Lan Yu Gu Encai Ou Weijian Xu Joseph J.richardson Rui Guo SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082China College of Chemistry and Materials Science Hunan Agricultural UniversityChangsha 410128China Department of Chemical Engineering The University of MelbourneParkville 3010Australia College of Environmental Science and Engineering Hunan UniversityChangsha 410082China School of Engineering RMIT UniversityMelbourneVictoria 3001Australia

Metal–phthalocyanines are a class of catalytically active materials promising in energy conversion and storage fields(e.g.,electrocatalysis).However,understanding and controlling the electrochemical properties in metal-phthalocyanine systems is ***,we elucidate the electrocatalytic origins of a series of cobalt-phthalocyanine molecular catalysts and finetune their electronic properties at the atomic level,both experimentally and *** interactions between the cobalt center and the local coordination environment are regulated by introducing either electron-donating or electron-withdrawing groups on the phthalocyanine ligand,and the spin-orbit splitting of cobalt is increased by~0.15 eV compared with the nonsubstituted ***,the aminated cobalt phthalocyanine-based electrocatalysts exhibit low free energies in the ratedetermining steps of the oxygen reduction(-1.68 eV)and oxygen evolution reactions(0.37 eV).This contributes to the high electrocatalytic activity(e.g.,a halfwave potential of 0.84 V and an overpotential of 0.30 V at 10 mAcm^(-2)),featuring a high selectivity of a four-electron pathway(i.e.,a negligible by-product of hydrogen peroxide).These catalysts also exhibit exceptional kinetic current density(Tafel slope of 100 mV dec^(-1))in oxygen reduction reactions,in addition to a superior power density(158 mWcm^(-2))and a high cycling stability(>1,300 cycles)in Zn-air batteries,outperforming the commercial Pt/C and/or RuO2counterparts.

关键词： interfacial wettability molecular catalysts carbon nanotubes density functional theory electrochemistry

Hydrocarbon indication in Rio Bonito Formation sandstone:Implication for CO_(2)storage in São Paulo,Brazil

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Energy Geoscience 2024年第1期5卷 331-341页

作者： richardson M.Abraham-A Haline V.Rocha Saulo B.de Oliveira Colombo C.G.Tassinarri Orlando C.da Silva Institute of Energy and Environment University of São PauloSão PauloBrazil Research Centre for Greenhouse Gas Innovation University of São PauloSão PauloBrazil

São Paulo State has witnessed CO_(2)storage-based investigations considering the availability of suitable geologic structures and proximity to primary CO_(2)source sinks related to bioenergy and carbon capture and storage(BECCS)*** current study presents the hydrocarbon viability evaluations and CO_(2)storage prospects,focusing on the sandstone units of the Rio Bonito *** objective is to apply petrophysical evaluations with geochemical inputs in predicting future hydrocarbon(gas)production to boost CO_(2)storage within the study *** study used data from eleven wells with associated wireline logs(gamma ray,resistivity,density,neutron,and sonic)to predict potential hydrocarbon accumulation and fluid mobility in the investigated *** samples(shale and carbonate)obtained from depths>200 m within the study location have shown bitumen *** geochemistry data of the Rio Bonito Formation shale beds suggest they are potential hydrocarbon source rocks and could have contributed to the gas accumulations within the sandstone *** drilled well data,e.g.,CB-1-SP and TI-1-SP,show hydrocarbon(gas)presence based on the typical resistivity and the combined neutron-density responses at depths up to 3400 m,indicating the possibility of other hydrocarbon members apart from the heavy oil(bitumen)observed from the near-surface rocks *** the three-dimensional(3-D)model,the free fluid indicator(FFI)is more significant towards the southwest and southeast of the area with deeper depths of occurrence,indicating portions with reasonable hydrocarbon recovery rates and good prospects for CO_(2)injection,circulation and permanent ***,future studies based on contemporary datasets are required to establish the hydrocarbon viability further,foster gas production events,and enhance CO_(2)storage possibilities within the region.

关键词： ParanáBasin Hydrocarbon indication Sandstone reservoirs Rio Bonito Formation CO_(2)storage Hydrocarbon recovery factor Fluid injection rate

A catalyst for integrating analytical biology,analytical chemistry, and engineering to improve drinking water safety: The groundbreaking work of Dr. Michael Plewa

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Journal of Environmental Sciences 2022年第7期34卷 6-9页

作者： Susan D.richardson Department of Chemistry and Biochemistry University of South CarolinaColumbiaSC 29208USA

It is interesting how a random encounter can profoundly change your life. My random encounter was with a young graduate student from Michael Plewa’s laboratory. The location was the 1999 American Chemical Society (ACS) Conference, where, following his talk, this promising researcher was being unfairly criticized by a well-established scientist. I disagreed with this scientist’s criticism, and I encouraged the student how I thought his work was important.

关键词： breaking integrating analytical

CAB Furnace Atmosphere Visualisation Using Computational Fluid Dynamics

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材料热处理学报 2004年第5B期25卷 729-732页

作者： P F Stratton A P richardson BOC Sheffield UK BOC Murray Hill NJ USA

In today’s automotive industry almost all car and truck radiators, oil coolers and air conditioning heat exchangers are manufactured using Nocolok Controlled Atmosphere Brazing (CAB). One of the most critical elements of the brazing process is the atmosphere used to protect the flux. Oxygen content is the major variable affecting the performance of the nitrogen atmosphere. Furnace design and flow rate are the major factors affecting oxygen content. Optimisation of these atmosphere parameters has a significant impact on operating cost, and on the quality and consistency of the brazed product. Computational fluid dynamics provides a tool to visualise the atmosphere conditions within the furnace and to explore the effects of changing some of the variables. Modelling the atmosphere in a typical CAB furnace has shown the importance of the integrity of the curtains in maintaining the low oxygen levels required for successful Nocolok brazing. For a given set of curtains it has shown that the only effective way of decreasing oxygen levels is to increase atmosphere gas flow.

关键词：铝钎焊 CAB炉子氮气 CFD 空气气流

A new technique helps to uncover unknown peptides and disinfection by-products in water

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Journal of Environmental Sciences 2016年第4期28卷 6-8页

作者： Susan D.richardson Cristina Postigo Department of Chemistry and Biochemistry University of South Carolina Department of Environmental Chemistry Institute for Environmental Assessment and Water Research-Spanish National Research Council(IDAEA-CSIC)

Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter（NOM）and thousands that derive from anthropogenic *** complex as these samples are,drinking water can be even more *** to disinfectants that are used to treat drinking water（e.g.,chlorine,chloramines,

关键词： Disinfection by-products(DBPs) Drinking water Halogenated peptides Liquid chromatography Natural organic matter(NOM) Non-targeted analysis Tandem mass spectrometry Water contaminants