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Optical observations of LIGO source GW 170817 by the Antarctic Survey Telescopes at Dome A,Antarctica

Science Bulletin 2017年第21期62卷 1433-1438页

作者： lei hu xuefeng wu igor andreoni michael c.b.ashley jeff cooke xiangqun cui fujia du zigao dai bozhong gu yi hu haiping lu xiaoyan li zhengyang li ensi liang liangduan liu bin ma zhaohui shang tianrui sun n.b.suntzeff charling tao syed a.uddin lifan wang xiaofeng wang haikun wen di xiao jin xu ji yang shihai yang xiangyan yuan hongyan zhou hui zhang jilin zhou zonghong zhu purple mountain observatory chinese academy of sciencesNanjing 210008China chinese center for antarctic astronomy Nanjing 210008China school of astronomy and space sciences university of science and technology of chinaHefei 230029China centre for astrophysics and supercomputing swinburne university of technologyHawthornVIC3122Australia the australian research council centre of excellence for gravitational wave discovery(ozgrav) Australia australian astronomical observatory north rydensw 2113Australia school of physics university of new south walesnsw 2052Australia the australian research council centre of excellence for all-sky astrophysics(caastro) Australia nanjing institute of astronomical optics and technology nanjing 210042China school of astronomy and space science and key laboratory of modern astronomy and astrophysics in ministry of education nanjing universitynanjing 210093China national astronomical observatories chinese academy of sciencesBeijing 100012China department of physics tianjin normal universitytianjin 300074china shanghai key laboratory for astrophysics shanghai normal universityshanghai 200234China george p.and cynthia woods mitchell institute for fundamental physics&astronomy texas a.&m.universitydepartment of physics and astronomy4242 tamucollege stationTX 77843USA aix marseille univ CNRS/N2P3CPPMmarseilleFrance physics department and tsinghua center for astrophysics(thca) tsinghua universityBeijing 100084China polar research institute of china shanghai 200136china department of astronomy beijing normal universitybeijing 100875china school of physics and technology wuhan universitywuhan 430072china

The LIGO detection of gravitational waves(GW) from merging black holes in 2015 marked the beginning of a new era in observational astronomy. The detection of an electromagnetic signal from a GW source is the critical next step to explore in detail the physics involved. The Antarctic Survey Telescopes(AST3),located at Dome A, Antarctica, is uniquely situated for rapid response time-domain astronomy with its continuous night-time coverage during the austral winter. We report optical observations of the GW source(GW 170817) in the nearby galaxy NGC 4993 using AST3. The data show a rapidly fading transient at around 1 day after the GW trigger, with the i-band magnitude declining from 17:23 ± 0:13 magnitude to 17:72 ± 0:09 magnitude in ~1:8 h. The brightness and time evolution of the optical transient associated with GW 170817 are broadly consistent with the predictions of models involving merging binary neutron stars. We infer from our data that the merging process ejected about ~10^(-2) solar mass of radioactive material at a speed of up to 30% the speed of light.

关键词： Gravitational waves Binary neutron stars Gamma-ray bursts

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Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： Victor V.Chizhikov igor Y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).

关键词： epithelium Figure center

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Risk Assessment of a Stochastic Service System

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Journal of Systems Science and Systems Engineering 2020年第5期29卷 537-554页

作者： igor Lazov Faculty of Informatics European University Skopje1000 SkopjeMacedonia

A stochastic service system of finite size M is comprised of identical service facilities,including or not a waiting queue,which simultaneously treats N customers,N∈{0,1,…,M}.Depending on the concepts of system information *** system entropy S=£(f),we promote a risk assessment *** definition,the system entropy is the uncertainty associated with the system,and the system expected loss is the risk associated with the ***,accepting the system information as loss function,we can identify risk and uncertainty,associated with the system,using the entropy as risk ***,we differ risk of the system(i.e.,risk observed by an outside observer),risk observed by an arriving customer,and risk observed by a departing customer,giving a separate expression for each ***,these risks are compared with each other,when the system has the same average number E(N)of customers seen by any *** three risk types(together with the three customer means)allow us to distinguish two systems obeying the same probability *** approach enables system operators to choose suitable values for system utilization and size,in view of the three risks *** developed procedure is applied to the information linear system,Erlang loss system,single-server queueing system with discouraged arrivals,Binomial system and Engset loss system.

关键词： Absolute and relative risk uncertainty system information and entropy system utilization stochastic service system

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The Functional Role of the Hollow Region of the Butterfly Pyrameis atalanta (L.) Scale

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Journal of Bionic Engineering 2008年第3期5卷 224-230页

作者： igor Kovalev Kinneret College on the Sea of Galilee Emek Hayarden 15132 Israel

Questions concerning the functional role of the hollow region of the butterfly Pyrameis atalanta （L.） scale are experimentally investigated. Attention was initially directed to this problem by observation of the complex microstrucmre of the butterfly scale as well as other studies indicating higher lift on butterfly wings covered with scale. The aerodynamic forces were measured for two oscillating scale models. Results indicated that the air cavity of an oscillating model of the Pyrameis atalanta （L.） scale increased the lift by a factor of 1.15 and reduced the damping coefficients by a factor of 1.38. The modification of the aerodynamic effects on the model of butterfly scale was due to an increase of the virtual air mass, which influenced the body. The hollow region of the scale increased the virtual air mass by a factor of 1.2. The virtual mass of the butterfly scale with the hollow region was represented as the sum of air mass of two imaginary geometrical figures： a circular cylinder around the scale and a right-angled parallelepiped within the hollow region. The interaction mechanism of the butterfly Pyrameis atalanta （L.） scale with a flow was described. This novel interaction mechanism explained most geometrical features of the airpermeable butterfly scale （inverted V-profile of the ridges, nozzle of the tip edge, hollow region, and openings of the upper lamina） and their arrangement.

关键词： bionic butterfly scale hollow region damped coefficient flapping motion virtual mass

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Use of GIS technology and cellular automata for modeling multiple socio-economic scenarios of regional spatial development and inter-regional cooperation

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Geo-Spatial Information Science 2023年第1期26卷 71-93页

作者： igor Musikhin Alexander Karpik Department of Photogrammetry and Remote Sensing Siberian State University of Geosystems and TechnologiesNovosibirskRussia Department of Space and Physical Geodesy Siberian State University of Geosystems and TechnologiesNovosibirskRussia

The advancement of effective spatial planning to support sustainable development and interregional cooperation has become an issue of serious concern for regional *** planning research helps to identify economic clusters and analyze their changing spatial patterns,which is important for understanding regional economic space dynamics and poten-tial inter-regional *** support decision-makers in the development of efficient plans of spatial development encompassing the identification of the best-suited territories,a combined Geographic Information System(GIS)based approach to interpret qualitatively expressed multiple socio-economic scenarios in quantitative map-based terms of graded suitability,and a formalized approach to the socio-economic evaluation of the territory is *** on GIS technology coupled with integrated cellular automata decision analysis techniques,the study provides a method that performs socio-economic assessment of the study area according to the generated scenarios of regional spatial and socio-economic *** proposed method is applied to Primorsky and Khabarovsk Krais,located in the Russian Far ***-economic scenarios of spatial development initiated by investors and regional authorities were assessed and *** generated socio-economic scenar-ios illustrate how the unified set of spatial and socio-economic variables can be linked and used to gain insights into inter-regional socio-economic and spatial *** application results demonstrate the advantage of the proposed method in identifying the best-suited unit areas for targeted regional development.

关键词： Geographic Information System(GIS) spatial development socioeconomic scenarios interregional cooperation open source software Cellular Automata(CA)

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Uncertainty in satellite remote sensing of snow fraction for water resources management

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Frontiers of Earth Science 2018年第4期12卷 711-727页

作者： igor APPEL TAG LLC WashingtonDistrict of Columbia20024USA

Snow fraction is an important component of land surface models and hydrologic models. Information on snow fraction also improves downstream products retrieved from remote sensing: vertical atmosphere profiles, soil moisture, heat fluxes, etc. The uncertainty of the fractional snow cover estimates must be determined, quantified, and reported to consider the suitability of the product for modeling, data assimilation and other applications. The reflectances of snow and non-snow are characterized by a very significant local variability and also by changes from one scene to another. The local snow and non-snow endmembers are approximated by the Normalized Difference Snow Index with a high accuracy. The magnitudes of snow and non-snow Normalized Difference Snow Indexes are scene-specific and calculated on the fly to retrieve snow fraction. The development of the Normalized Difference Snow Index based algorithms to estimate snow fraction including a scene-specific approach taking local snow and non-snow properties into account is considered an optimal way to fractional snow retrieval from moderate resolution optical remote sensing observations. The Landsat reference data are used to estimate the performance of the fractional snow cover algorithms at moderate resolution and to compare the quality of alternative algorithms. The validation results demonstrate that the performance of the algorithms using Normalized Difference Snow Index has advantages. The advantages achieved in snow fraction retrieval lead to improved estimate of snow water equivalent and changes in snow cover state contributing to better modeling of land surface and hydrologic regime. The success of managing water resources on the whole depends on coordinating described investigations with the works of other researchers developing further enhanced models.

关键词： algorithm remote sensing uncertainty validation snow cover fraction

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Life and Death of Stationary Linear Response in Anomalous Continuous Time Random Walk Dynamics

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Communications in Theoretical Physics 2014年第10期61卷 497-504页

作者： igor Goychuk Institute for Physics and Astronomy University of PotsdamKarl-Liebknecht-Str.24/2514476 Potsdam-GolmGermany

Linear theory of stationary response in systems at thermal equilibrium requires to find equilibrium correlation function of unperturbed responding system. Studies of the response of the systems exhibiting anomalously slow dynamics are often based on the continuous time random walk description(CTRW) with divergent mean waiting *** bulk of the literature on anomalous response contains linear response functions like one by Cole-Cole calculated from such a CTRW theory and applied to systems at thermal equilibrium. Here we show within a fairly simple and general model that for the systems with divergent mean waiting times the stationary response at thermal equilibrium is absent,in accordance with some recent studies. The absence of such stationary response(or dying to zero non-stationary response in aging experiments) would confirm CTRW with divergent mean waiting times as underlying physical relaxation mechanism, but reject it otherwise. We show that the absence of stationary response is closely related to the breaking of ergodicity of the corresponding dynamical variable. As an important new result, we derive a generalized Cole-Cole response within ergodic CTRW dynamics with finite waiting time. Moreover, we provide a physically reasonable explanation of the origin and wide presence of 1/f noise in condensed matter for ergodic dynamics close to normal, rather than strongly deviating.

关键词： random walks anomalous response and relaxation stationarity aging 1/f noise

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A NUMERICAL METHOD FOR SOLVING NONLINEAR INTEGRO-DIFFERENTIAL EQUATIONS OF FREDHOLM TYPE

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Journal of Computational Mathematics 2016年第3期34卷 262-284页

作者： igor Boglaev Institute of Fundamental Sciences Massey UniversityPrivate Bag 11-222 Palmerston North New Zealand

The paper deals with a numerical method for solving nonlinear integro-parabolic prob- lems of Fredholm type. A monotone iterative method, based on the method of upper and lower solutions, is constructed. This iterative method yields two sequences which converge monotonically from above and below, respectively, to a solution of a nonlinear difference scheme. This monotone convergence leads to an existence-uniqueness theorem. An analy- sis of convergence rates of the monotone iterative method is given. Some basic techniques for construction of initial upper and lower solutions are given, and numerical experiments with two test problems are presented.

关键词： Nonlinear integro-parabolic equations of Fredholm type Nonlinear differenceschemes Monotone iterative methods The method of upper and lower solutions.

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UNIFORM QUADRATIC CONVERGENCE OF A MONOTONE WEIGHTED AVERAGE METHOD FOR SEMILINEAR SINGULARLY PERTURBED PARABOLIC PROBLEMS＊

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Journal of Computational Mathematics 2013年第6期31卷 620-637页

作者： igor Bogluev Institute of Fundamental Sciences Massey University Palmerston North New Zealand

This paper deals with a monotone weighted average iterative method for solving semilinear singularly perturbed parabolic problems. Monotone sequences, based on the ac- celerated monotone iterative method, are constructed for a nonlinear difference scheme which approximates the semilinear parabolic problem. This monotone convergence leads to the existence-uniqueness theorem. An analysis of uniform convergence of the monotone weighted average iterative method to the solutions of the nonlinear difference scheme and continuous problem is given. Numerical experiments are presented.

关键词： Semilinear parabolic problem Singular perturbation Weighted average scheme,Monotone iterative method Uniform convergence.

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New solutions for old challenges in glaucoma treatment:is taurine an option to consider?

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Neural Regeneration Research 2021年第5期16卷 967-971页

作者： igor Iezhitsa Renu Agarwal School of Medicine International Medical UniversityKuala LumpurMalaysia Volgograd State Medical University Research Centre for Innovative MedicinesVolgogradRussian Federation

Glaucoma is a range of progressive optic neuropathies characterized by progressive retinal ganglion cell loss and visual field *** is recognized as a leading cause of irreversible blindness affecting more than 70 million people ***,reduction of intraocular pressure,a widely recognized risk factor for glaucoma development,is the only pharmacological strategy for slowing down retinal ganglion cell loss and disease ***,retinal ganglion cell death and visual field loss have been observed in normotensive glaucoma,suggesting that the disease process is partially independent of intraocular *** is one of the agents that have attracted attention of researchers *** has been shown to be involved in multiple cellular functions,including a central role as a neurotransmitter,as a trophic factor in the central nervous system development,as an osmolyte,as a neuromodulator,and as a *** also plays a role in the maintenance of the structural integrity of the membranes and in the regulation of calcium transport and *** is known to prevent N-methyl-D-aspartic acid-induced excitotoxic injury to retinal ganglion cells.A recently published study clearly demonstrated that taurine prevents retinal neuronal apoptosis both in vivo and in *** effect of taurine may be attributed to direct inhibition of apoptosis,an activation of brain derived neurotrophic factor-related neuroprotective mechanisms and reduction of retinal oxidative and nitrosative *** studies are needed to fully explore the potential of taurine as a neuroprotective agent,so that it can be applied in clinical practice,particularly for the treatment of *** objective of current review was to summarize recent evidence on neuroprotective properties of taurine in glaucoma.

关键词： apoptosis excitotoxicity glaucoma oxidative and nitrosative stresses retinal neuroprotection taurine

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