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Fast rectangular matrix multiplication and some applications

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Science China Mathematics 2008年第3期51卷 389-406页

作者： victor Y PAN Department of Mathematics and Computer Science.Lehman College City University of New York BronxNew York 10468 USA

We study asymptotically fast multiplication algorithms for matrix pairs of arbitrary dimensions, and optimize the exponents of their arithmetic complexity bounds. For a large class of input matrix pairs, we improve the known exponents. We also show some applications of our results: (i) we decrease from O(n 2 + n 1+o(1)logq) to O(n 1.9998 + n 1+o(1)logq) the known arithmetic complexity bound for the univariate polynomial factorization of degree n over a finite field with q elements; (ii) we decrease from 2.837 to 2.7945 the known exponent of the work and arithmetic processor bounds for fast deterministic (NC) parallel evaluation of the determinant, the characteristic polynomial, and the inverse of an n × n matrix, as well as for the solution to a nonsingular linear system of n equations; (iii) we decrease from O(m 1.575 n) to O(m 1.5356 n) the known bound for computing basic solutions to a linear programming problem with m constraints and n variables.

关键词： rectangular matrix multiplication asymptotic arithmetic complexity bilinear algorithm polynomial factorization over finite fields 68Q25 11Y16

Tunable electrochemistry of gold-silver alloy nanoshells

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Nano Research 2018年第12期11卷 6336-6345页

作者： Lorenzo Russo victor Puntes Arben Merkoci Catalan Institute of Nanoscience and Nanotechnology (ICN2) CSIC and BISTCampus UABBellaterra08193BarcelonaSpain Universitat Autonoma de Barcelona (UAB) Campus UABBellaterra08193BarcelonaSpain Vail d'Hebron Institut de Recerca (VHIR) 08035BarcelonaSpain Institucio Catalana de Recerca i Estudis Avancats (ICREA) P Llub Companys 2308010BarcelonaSpain

The widespread and increasing interest in enhancing biosensing technologies by increasing their sensitivities and lowering their costs has led to the exploration and application of complex nanomaterials as signal transducers and enhancers. In this work, the electrochemical properties of monodispersed AuAg alloy nanoshells (NSs) with finely tunable morphology, composition, and size are studied to assess their potential as electroactive labels. The controlled corrosion of their silver content, caused by the oxidizing character of dissolved oxygen and chlorides of the electrolyte, allows the generation of a reproducible electrochemical signal that is easily measurable through voltammetric techniques. Remarkably, the underpotential deposition of dissolved Ag+ catalyzed on AuAg NS surfaces is observed and its dependence on the nanoparticle morphology, size, and elemental composition is studied, revealing a strong correlation between the relative amounts of the two metals. The highest catalytic activity is found at Au/Ag ratios higher than ≈ 10, showing how the synergy between both metals is necessary to trigger the enhancement of Ag+ reduction. The ability of AuAg NSs to generate an electrocatalytic current without the need for any strong acid makes them an extremely promising material for biosensing applications.

关键词： Au nanoshells nanoparticles surface chemistry underpotential deposition

Determining short chain fatty acids in sewage sludge hydrolysate: A comparison of three analytical methods and investigation of sample storage effects

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Journal of Environmental Sciences 2014年第4期26卷 926-933页

作者： victor Ibrahim Tobias Hey Karin Jonsson VA SYD SE-201 21 Malmo Sweden Water and Environmental Engineering Department of Chemical Engineering Lund University SE-21100 Lund Sweden

In anaerobic digestion, the production of short-chain fatty acids （SCFAs） can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration （TITRA5）, gas chromatography （GC）, and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample＇s matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements.

关键词： five pH point titration gas chromatography spectrophotometry short-chain fatty acids sludge hydrolysis sample storage

MXene supported surface plasmons on telecommunications optical fibers

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Light(Science & Applications) 2022年第2期11卷 212-220页

作者： victor Pacheco-Peña Toby Hallam Noel Healy School of Mathematics Statistics and PhysicsNewcastle UniversityNewcastle Upon Tyne NE17RUUK

MXenes,an emerging class of two-dimensional materials,exhibit characteristics that promise significant potential for their use in next generation optoelectronic *** interplay between interband transitions and boundary effects offer the potential to tune the plasma frequencies over a large spectral range from the near-infrared to the *** tuneability along with the‘layered’nature of the material not only offer the flexibility to produce plasmon resonances across a wide range of wavelengths,but also add a degree of freedom to the sensing mechanism by allowing the plasma frequency to be *** we show,numerically,that MXenes can support plasmons in the telecommunications frequency range and that surface plasmon resonances can be excited on a standard MXene coated side polished optical ***,presenting the tantalising prospect of highly selective distributed optical fiber sensor networks.

关键词： fibers excited transitions

Full time adult credential students?instructional preferences at California State University, Long Beach: pedagogy or andragogy?

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2004年第3期5卷 116-121页

作者： WANG victor Occupational Studies Department California State University

This study investigated the instructional preferences of full time adult credential students after they took a live course called Principles of Adult Education at California State University, Long Beach (CSULB) in the fall semester of 2002. These full time adult credential students had been working on their adult teaching credentials to meet the competencies specified by the California Commission on Teacher Credentialing. The course introduced students to Andragogy developed by Malcolm Knowles out of the andragogical model developed by Lindeman (1926). The study used Principles of Adult Learning Scales (PALS), advanced by Gary Conti in 1983 to measure instructional preferences. Data were collected from 30 (100% of 30) full time adult credential students enrolled in a live course to determine their instructional preferences of helping adults learn. The results of the study showed in most cases these adult learning professionals taught adult students andragogically; in some cases they taught adult students pedagogically.

关键词： Andragogy Principles of Adult Learning Scales (PALS) Instructional preferences California State University

State and perspectives on flavonoid neuroprotection against aminochrome-induced neurotoxicity

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Neural Regeneration Research 2021年第9期16卷 1797-1798页

作者： victor Silva Juan Segura-Aguilar Laboratory of Neurochemistry and Cell Biology Department of Biochemistry and BiophysicsInstitute of Health SciencesFederal University of Bahia40110-100SalvadorBahiaBrazil Molecular and Clinical Pharmacology ICBMFaculty of MedicineUniversity of ChileChile

Parkinson's disease(PD) motor symptoms are induced by the loss of dopaminergic neurons containing neuromelanin in the nigrostriatal system. The exact mechanism that triggers the degeneration of the nigrostriatal neurons is still unknown but there is general consensus in the scientific community that mitochondrial dysfunction, alpha-synuclein aggregation to neurotoxic oligomers, protein degradation dysfunction of both lysosomal and proteasomal systems, endoplasmic reticulum stress.

关键词： degeneration reticulum aggregation

Mathematical modeling of building structures and nonlinear differential equations

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第3期11卷 154-160页

作者： victor Orlov Yulia Zheglova Moscow State University of Civil Engineering Yaroslavskoye Shosse 26 Moscow 129337Russia

Nonlinear differential equations with moving singular points require emergence and development of new approximate methods of *** this paper,we give a solution to one of the problems of the analytical approximate method for solving nonlinear differential equations with moving singular points,and study the influence of the perturbation of the initial conditions on the analytical approximate solution in the analytic *** material was tested using a numerical experiment confirming its *** theoretical material presented in this paper allows researchers to use nonlinear differential equations with moving singular points when designing mathematical models of building structures.

关键词： Mathematical modeling moving singular points a priori estimate approximate solution a posteriori error estimate

(In)visibilities About the Vulnerabilities of People with Visual Impairments to Disasters and Climate Change:A Case Study in Cuiabaá,Brazil

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International Journal of Disaster Risk Science 2022年第1期13卷 38-51页

作者： Giselly Gomes victor Marchezini Michele Sato Federal University of Mato Grosso(PPGE/UFMT) CuiabaMT 78060-900Brazil ICEMAT-Institute of the Blind of the State of Mato Grosso CuiabaMT 78058-340Brazil Cemaden-National Early Warning and Monitoring Center of Natural Disasters Avenida Altino BondesanDistrito de Eugenio de MeloSao Jose dos CamposSP 12247-016Brazil Doctorate Program on Earth System Science National Institute for Space ResearchSao Jose dos CamposBrazil Programa de Pos-Graduaao em Desastres Naturais ICT/Unesp-CemadenSao Jose dos CamposBrazil

People with visual impairments(PwVI)represent a heterogeneous social group who often experience significant disabling barriers in exercising their rights throughout their life *** dimensions of vulnerability of PwVI to disasters and climate change is an important issue to reduce the culture of neglected *** date,few studies have analyzed visual impairment and disaster risk reduction(DRR)in the countries of Latin America and the *** exploratory qualitative research project analyzed how to include PwVI in the DRR policies of *** research question is:how can we include PwVI in the discussion of DRR and climate change?The response to this question is part of a joint effort that involved a university,a hazard monitoring agency,and three institutions that work with *** three main results of the project are:(1)a mapping method to identify the exposure of PwVI to landslides and floods,and to create tactile risk maps tailored to them;(2)incorporating the voices of PwVI regarding their vulnerabilities and capacities with respect to disasters and climate change,achieved through shared interaction during 15 face to face interviews and one workshop attended by 100 people;and(3)an initiative of inclusive education to reduce some of the disabling barriers that intensify vulnerability.

关键词： Brazil Climate injustice Disaster risk Environmental education Inclusive education Sight impairment

Compound eyes of insects and crustaceans： Some examples that show there is still a lot of work left to be done

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Insect Science 2015年第3期22卷 461-481页

作者： victor Benno Meyer-Rochow Department of Biology University of Oulu P.O. Box 3000 FIN-90014 Oulu Finland

Similarities and differences between the 2 main kinds of compound eye （apposition and superposition） are briefly explained before several promising topics for research on compound eyes are being introduced. Research on the embryology and molecular control of the development of the insect clear-zone eye with superposition optics is one of the suggestions, because almost all of the developmental work on insect eyes in the past has focused on eyes with apposition optics. Age- and habitat-related ultrastructural studies of the retinal organization are another suggestion and the deer cad Lipoptena cervi, which has an aerial phase during which it is winged followed by a several months long parasitic phase during which it is wingless, is mentioned as a candidate species. Sexual dimorphism expressing itself in many species as a difference in eye structure and function provides another promising field for compound eye researchers and so is a focus on compound eye miniaturization in very small insects, especially those that are aquatic and belong to species, in which clear-zone eyes are diagnostic or are tiny insects that are not aquatic, but belong to taxa like the Diptera for instance, in which open rather than closed rhabdoms are the rule. Structures like interommatidial hairs and glands as well as corneal microridges are yet another field that could yield interesting results and in the past has received insufficient consideration. Finally, the dearth of information on distance vision and depth perception is mentioned and a plea is made to examine the photic environment inside the foam shelters of spittle bugs, chrysales of pupae and other structures shielding insects and crustaceans.

关键词： aging miniaturization photoreceptors sexual dimorphism vision