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International Journal of Geosciences 2021年第3期12卷 233-252页

作者： eitan hirsch Eyal Agassi Alon Manor Environmental Physics Department Environmental Sciences Division Israel Institute for Biological Research Ness Ziona Israel

Quantitative real-time retrieval of concentration-lengths (CL) through gaseous plumes is an important tool for environmental monitoring, enabling remote monitoring of emissions from industrial facilities and risk assessment in scenarios of toxic gas releases. The adoption of LWIR (Long Wave InfraRed) hyperspectral imaging as a leading technique for remote gas plume detection paved the way for an introduction of a precise CL estimation and two-dimensional (2D) mapping. A novel methodology for evaluating and characterizing the performance of a retrieval algorithm is presented. The algorithm utilizes state-of-the-art retrieved hyperspectral 2D mapping and is applied on a series of localized atmospheric tracer gas (SF6) releases in monitored environmental conditions. The retrieved CL distributions are compared to a numeric atmospheric T&D (Transport and Diffusion) model. Satisfactory agreement between retrieved and simulated CL prediction is manifested, and the uncertainty involved is quantified. Possible sources for the remained discrepancies between retrieved and simulated CL values are characterized, and methods to minimize them are discussed.

关键词： Hyperspectral Infrared Gaseous Plumes Concentration-Length Quantification Atmospheric Transport and Diffusion (T&D) Model

Revisting High-Resolution Schemes with van Albada Slope Limiter

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Communications on Applied Mathematics and Computation 2024年第3期6卷 1924-1953页

作者： Jingcheng Lu eitan Tadmor Department of Mathematics University of MarylandCollege ParkMDUSA School of Mathematics University of MinnesotaMinneapolisMNUSA Department of Mathematics and Institute for Physical Sciences and Technology University ofMarylandCollegeParkMDUSA

Slope limiters play an essential role in maintaining the non-oscillatory behavior of high-resolution methods for nonlinear conservation *** family of minmod limiters serves as the prototype ***,we revisit the question of non-oscillatory behavior of high-resolution central schemes in terms of the slope limiter proposed by van Albada et al.(Astron Astrophys 108:76–84,1982).The van Albada(vA)limiter is smoother near extrema,and consequently,in many cases,it outperforms the results obtained using the standard minmod *** particular,we prove that the vA limiter ensures the one-dimensional Total-Variation Diminishing(TVD)stability and demonstrate that it yields noticeable improvement in computation of one-and two-dimensional systems.

关键词： High resolution Limiters Total-Variation Diminishing(TVD)stability Central schemes

Constraint Preserving Schemes Using Potential-Based Fluxes *** Transport Equations

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Communications in Computational Physics 2011年第3期9卷 688-710页

作者： Siddhartha Mishra eitan Tadmor Centre of Mathematics for Applications(CMA) University of OsloP.O.Box 1053BlindernN-0316 OsloNorway Center of Scientific Computation and Mathematical Modeling(CSCAMM) and Department of Mathematicsand Institute for Physical Sciences and Technology(IPST)University of MarylandMD 20742-4015USA

We consider constraint preserving multidimensional evolution equations.A prototypical example is provided by the magnetic induction equation of plasma *** constraint of interest is the divergence of the magnetic *** design finite volume schemes which approximate these equations in a stable manner and preserve a discrete version of the *** schemes are based on reformulating standard edge centered finite volume fluxes in terms of vertex centered *** potential-based approach provides a general framework for faithful discretizations of constraint transport and we apply it to both divergence preserving as well as curl preserving *** present benchmark numerical tests which confirm that our potential-based schemes achieve high resolution,while being constraint preserving.

关键词： Multidimensional evolution equations magnetohydrodynamics finite-difference finite volume schemes constraint transport potential-based schemes

Geometric Counting on Wavefront Real Spherical Spaces

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Acta Mathematica Sinica,English Series 2018年第3期34卷 488-531页

作者： Bernhard KROTZ eitan SAYAG Henrik SCHLICHTKRULL Universitat Paderborn Institut Jur MathematikWarburger Strafle 10033098 PaderbornDeutschland Department of Mathematics Ben Gurion University of the NegevP.O.B.653Be'er Sheva 84105Israel Department of Mathematics University of CopenhagenUniversitetsparken 5DK-2100 Copenhagen ODenmark

We provide L^p-versus L~∞-bounds for eigenfunctions on a real spherical space Z of wavefront type. It is shown that these bounds imply a non-trivial error term estimate for lattice counting on Z. The paper also serve... 详细信息

关键词： Homogeneous spaces real spherical spaces lattice counting error term wavefront lemma spectral analysis norm comparison of eigenfunctions

Improving localization precision of Brillouin measurements using spectral autocorre lation analysis

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Journal of Innovative Optical Health Sciences 2017年第6期10卷 35-42页

作者： eitan Edrei Milos Nikolic Giuliano Scarcelli Fischell Department of Bioengineering University of Maryland College ParkMaryland 20742USA

Brillouin spectroscopy is a powerful tool for measuring the mechanical properties of materials without *** sensitivity to mechanical changes that a Brillouin spectrometer can detect is determined by the precision to which a spectral peak can be *** localization precision is however fundamentally limited by the low mumber of photons within a Brillouin measurement,as wel as by intrinsic noise of the ***,we present a method to improve the spectral sensitivity of Brillouin measurements by exploiting the autocorelation function of the *** show that by performing a localization process on the autocorrelation function nearly 20%increase in localizat ion precision can be *** result is consistent bet ween our theoretical treatment,numerical simulation and experimental *** further study the efect of back-ground noise on the precision im provement for realistic scenarios.

关键词： Brillouin microscopy localization

Differentiation of murine male germ cells to spermatozoa n a soft agar culture system

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Asian Journal of Andrology 2012年第2期14卷 285-293页

作者： Mahmoud Abu Elhija eitan Lunenfeld Stefan Schlatt Mahmoud Huleihel The Shraga Segal Department of Microbiology and Immunology Faculty of Health Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Department of Obstetrics and Gynecology Soroka University Medical Center and Faculty of Health Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Centre of Reproductive Medicine and Andrology of the University of Menster Menster 84149 Germany

Establishment of an in vitro system that allows the development of testicular germ cells to sperm will be valuable for studies of spermatogenesis and future treatments for male infertility. In the present study, we developed in vitro culture conditions using three-dimensional agar culture system （SACS）, which has the capacity to induce testicular germ cells to reach the final stages of spermatogenesis, including spermatozoa generation. Seminiferous tubules from testes of 7-day-old mice were enzymatically dissociated, and intratubular cells were cultured in the upper layer of the SACS in RPMI medium supplemented with fetal calf serum （FCS）. The lower layer of the SACS contained only RPMI medium supplemented with FCS. Colonies in the upper layer were isolated after 14 and 28 days of culture and were classified according to their size. Immunofluorescence and real-time PCR were used to analyse specific markers expressed in undifferentiated and differentiated spermatogonia （Vasa, Dazl, OCT-4, C-Kit, GFR- a-l, CD9 and a-6-integrin）, meiotic cells （LDH, Crem-1 and Boule） and post-meiotic cells （Protamine-1, Acrosin and SP-IO）. Our results reveal that it is possible to induce mouse testicular pre-meiotic germ cell expansion and induce their differentiation to spermatozoa in SACS. The spermatozoa showed normal morphology and contained acrosomes. Thus, our results demonstrate that SACS could be used as a novel in vitro system for the maturation of pre-meiotic mouse germ cells to post-meiotic stages and morphologically-normal spermatozoa.

关键词： acrosome agar in vitro culture meiosis spermatogenesis spermatogonia spermatozoa testis

Regulation of spermatogenesis by paracrine/autocrine testicular factors

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Asian Journal of Andrology 2004年第3期6卷 259-268页

作者： Mahmoud Huleihel eitan Lunenfeld Department of Microbiology and Immunology and BGU Cancer Research Center Faculty of Health Sciences Ben-Gurion University of the NegevBeer-ShevaIsraelDepartment of Obstetrics and GynecologySoroka University Medical Center Faculty of Health SciencesBen-Gurion University of the NegevBeer-ShevaIsrael

Spermatogenesis is a complex process regulated by endocrine and testicular paracrine/autocrine factors. Gonadotropins are involved in the regulation of several testicular paracrine factors, mainly of the IL-1 family and testicular hormones. Testicular cytokines and growth factors (such as IL-1, IL-6, TNF, IFN-γ, LIF and SCF) were shown to affect both the germ cell proliferation and the Leydig and Sertoli cells functions and secretion. Cytokines and growth factors are produced by immune cells and in the interstitial and seminiferous tubular compartments by various testicular cells, including Sertoli, Leydig, peritubular cells, spermatogonia, differentiated spermatogonia and even spermatozoa. Corresponding cytokine and growth factor receptors were demonstrated on some of the testicular cells. These cytokines also control the secretion of the gonadotropins and testosterone in the testis. Under pathological conditions the levels of pro-inflammatory cytokines are increased and negatively affected spermatogenesis. Thus, the expression levels and the mechanisms involved in the regulation of testicular paracrine/autocrine factors should be considered in future therapeutic strategies for male infertility.

关键词： spermatogenesis paracrine autocrine cytokine growth factor

Biosafety and biosecurity in the era of biotechnology:The Middle East region

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Journal of Biosafety and Biosecurity 2022年第2期4卷 130-145页

作者： Laith AL-eitan Malek Alnemri Department of Biotechnology and Genetic Engineering Jordan University of Science and TechnologyIrbid 22110Jordan

Biotechnology became a paradigm-shifting science among all subfields of *** benefits of biotechnology have reached many practical fields,whether human health,animal,and/or ***,wherever there is a biotechnology practice,there is an associated biohazard with it,and its negative impact may reach all living entities including ***,the cooperation of the leading institutions in this field has culminated in creating the concepts and applications of biosafety and *** countries of the Middle East are considered biotechnology-practicing and have shown a clear acceptance to this *** unfortunately,the Middle East region is one that is facing the most multichallenges,which would constitute real and noticeable concern at the local and international *** challenges represented by wars and armed conflicts,deteriorating economic conditions,the large number of refugees,and the spread of many ***,limiting the region’s ability to deal with the surrounding biological hazards and struggling the way to the one health ***,this article aims to shed light on the activities of the Middle East countries in the field of biotechnology and to address potential biological threats,whether natural such as the spread of viruses,or intentional such as biological attacks and *** article also shows the capacity of the countries of the region in the field of biosafety and biosecurity based on available ***,some countries are lacking the required level of preparedness to face potential biological ***-institutional and international cooperation between the concerned countries will significantly enhance the capacity of the region in biosafety and biosecurity to meet the level of biological *** methodology:wide range of related keywords(based on the section)combined with the name of the region,or one country individually have been searched using available search engines a

关键词： Biosafety Biosecurity Biotechnology Bioterrorism Biological weapons Middle east Viruses

Non-Oscillatory Hierarchical Reconstruction for Central and Finite Volume Schemes

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Communications in Computational Physics 2007年第5期2卷 933-963页

作者： Yingjie Liu Chi-Wang Shu eitan Tadmor Mengping Zhang School of Mathematics Georgia Institute of TechnologyAtlantaGA 30332-0160USA. Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Department of Mathematics Institute for Physical Science and Technologyand Center of Scientific Computation and Mathematical Modeling(CSCAMM)University of MarylandCollege ParkMD 20742USA Department of Mathematics University of Science and Technology of ChinaHefeiAnhui 230026China

This is the continuation of the paper”Central discontinuous Galerkin methods on overlapping cells with a non-oscillatory hierarchical reconstruction”by the same *** hierarchical reconstruction introduced therein is applied to central schemes on overlapping cells and to finite volume schemes on non-staggered *** takes a new finite volume approach for approximating non-smooth solutions.A critical step for high-order finite volume schemes is to reconstruct a non-oscillatory high degree polynomial approximation in each cell out of nearby cell *** the paper this procedure is accomplished in two steps:first to reconstruct a high degree polynomial in each cell by using e.g.,a central reconstruction,which is easy to do despite the fact that the reconstructed polynomial could be oscillatory;then to apply the hierarchical reconstruction to remove the spurious oscillations while maintaining the high *** numerical computations for systems of conservation laws are performed without characteristic *** particular,we demonstrate that this new approach can generate essentially non-oscillatory solutions even for 5th-order schemes without characteristic decomposition.

关键词： Central scheme discontinuous Galerkin method ENO scheme finite volume scheme MUSCL scheme TVD scheme.

Femtosecond electron microscopy of relativistic electron bunches

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Light(Science & Applications) 2023年第6期12卷 1010-1019页

作者： Yang Wan Sheroy Tata Omri Seemann eitan YLevine Slava Smartsev Eyal Kroupp Victor Malka Department of Physics of Complex Systems Weizmann Institute of ScienceRehovot 7610001Israel

The development of plasma-based accelerators has enabled the generation of very high brightness electron bunches of femtosecond duration,micrometer size and ultralow emittance,crucial for emerging applications including ultrafast detection in material science,laboratory-scale free-electron lasers and compact colliders for high-energy *** precise characterization of the initial bunch parameters is critical to the ability to manipulate the beam properties for downstream *** diagnostic of such ultra-short and high charge density laser-plasma accelerated bunches,however,remains very *** we address this challenge with a novel technique we name as femtosecond ultrarelativistic electron microscopy,which utilizes an electron bunch from another laser-plasma accelerator as a *** contrast to conventional microscopy of using very low-energy electrons,the femtosecond duration and high electron energy of such a probe beam enable it to capture the ultra-intense space-charge fields of the investigated bunch and to reconstruct the charge distribution with very high spatiotemporal resolution,all in a single *** the experiment presented here we have used this technique to study the shape of a laser-plasma accelerated electron beam,its asymmetry due to the drive laser polarization,and its beam evolution as it exits the *** anticipate that this method will significantly advance the understanding of complex beam-plasma dynamics and will also provide a powerful new tool for real-time optimization of plasma accelerators.

关键词： relativistic utilize precise