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Is sympatric speciation in nature only possible with micro-parapatry? A new case study of glacial lake cyprinid fishes

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National Science Review 2022年第12期9卷 21-23页

作者： christopher H.Martin Department of Integrative Biology University of California Museum of Vertebrate Zoology University of California

Although numerous theoretical models of the feasibility and necessary conditions for sympatric speciation abound in the literature,clear-cut examples in nature remain ***,as always in speciation research,this statement strongly depends on your definition of sympatric speciation [1-3].If using the biogeographic definition of sympatric speciation as divergence between individuals in a population within’cruising range’of each other [4],

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Signals and noise in the octavolateralis systems: What is the impact of human activities on fish sensory function?

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Integrative Zoology 2015年第1期10卷 4-14页

作者： christopher B.BRAUN Department of Psychology Hunter CollegeCity University of New YorkNew YorkNYUSA

The octavolateralis systems of fishes include the vestibular,auditory,lateral line and electrosensory *** are united by common developmental and neuro-computational features,including hair cell sensors and computations based on cross-neuron analyses of differential hair cell stimulation *** systems also all use both spectral and temporal filters to separate signals from each other and from noise,and the distributed senses(lateral line and electroreception)add spatial filters as *** all sensory systems,these sensors must provide the animal with guidance for adaptive behavior within a sensory scene composed of multiple stimuli and varying levels of ambient noise,including that created by human *** the extreme,anthropogenic activities impact the octavolateralis systems by destroying or degrading the habitats that provide ecological resources and sensory *** slightly lesser levels of effect,anthropogenic pollutants can be damaging to fish tissues,with sensory organs often the most *** exposed sensory cells of the lateral line and electrosensory systems are especially sensitive to aquatic *** still lesser levels of impact,anthropogenic activities can act as both acute and chronic stressors,activating hormonal changes that may affect behavioral and sensory ***,human activities are now a nearly ubiquitous presence in aquatic habitats,often with no obvious effects on the animals exposed to *** noise,indigenous and industrial fishing techniques,and all the ancillary noises of human civilization form a major part of the soundscape of *** fish use these new sources of information about their habitat is a new and burgeoning field of study.

关键词： audition,electrosense lateral line soundscape underwater noise

Spherical Tropical Geometry:a Survey of Recent Developments

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Acta Mathematica Sinica,English Series 2018年第3期34卷 454-465页

作者： Kiumars KAVEH christopher MANON Department of Mathematics University of PittsburghPittsburghPAUSA Department of Mathematics Univcrsity of KentuckyLexingtonKYUSA

This is a survey of some recent results on spherical tropical geometry.

关键词： Tropical geometry reductive group action spherical variety Grbner theory

FINITE ELEMENT EXTERIOR CALCULUS FOR PARABOLIC EVOLUTION PROBLEMS ON RIEMANNIAN HYPERSURFACES

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Journal of Computational Mathematics 2018年第6期36卷 792-832页

作者： Michael Hoist christopher Tiee Department of Mathematics University of California San Diego La Jolla CA 92093 USA

Over the last ten years, Finite Element Exterior Calculus （FEEC） has been developed as a general framework for linear mixed variational problems, their numerical approximation by mixed methods, and their error analysis. The basic approach in FEEC, pioneered by Arnold, Falk, and Winther in two seminal articles in 2006 and 2010, interprets these problems in the setting of Hilbert complexes, leading to a more general and complete understanding. Over the last five years, the FEEC framework has been extended to a broader set of problems. One such extension, due to Hoist and Stern in 2012, was to problems with variational crimes, allowing for the analysis and numerical approximation of linear and geometric elliptic partial differential equations oil Riemannian manifolds of arbitrary spatial dimension. Their results substantially generalize the existing surface finite element approximation theory in several respects. In 2014, Gillette, Hoist, and Zhu extended FEEC in another direction, namely to parabolic and hyperbolic evolution systems by combining the FEEC framework for elliptic operators with classical approaches for parabolic and hyperbolic operators, by viewing solutions to the evolution problem as lying in Bochner spaces （spaces of Banach-space valued parametrized curves）. Related work on developing an FEEC theory for parabolic evolution problems has also been done independently by Arnold and Chen. In this article, we extend the work of Gillette-Holst- Zhu and Arnold-Chen to evolution problems on Riemannian manifolds, through tile use of framework developed by Holst and Stern for analyzing variational crimes. We establish a priori error estimates that reduce to the results from earlier work in tile flat （non-criminal） setting. Some numerical examples are also presented.

关键词： FEEC Elliptic equations Evolution equations Approximation theory Inf-supconditions A priori estimates Variational crimes Equations on manifolds

Using agent-based simulation to assess diseaseprevention measures during pandemics

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Chinese Physics B 2021年第9期30卷 643-651页

作者： Yunhe Tong christopher King Yanghui Hu Department of Engineering Mathematics University of BristolBristol BS81UBUK State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230027China

Despite the growing interest in macroscopic epidemiological models to deal with threats posed by pandemics such as COVID-19,little has been done regarding the assessment of disease spread in day-to-day life,especially within buildings such as supermarkets where people must obtain necessities at the risk of exposure to ***,we propose an integrated customer shopping simulator including both shopper movement and choice behavior,using a force-based and discrete choice model,*** a simple extension to the force-based model,we implement the following preventive measures currently taken by supermarkets;social distancing and one-way systems,and different customer habits,assessing them based on the average individual disease exposure and the time taken to complete shopping(shopping efficiency).Results show that maintaining social distance is an effective way to reduce exposure,but at the cost of shopping *** find that the one-way system is the optimal strategy for reducing exposure while minimizing the impact on shopping *** should also visit supermarkets less frequently,but buy more when they do,if they wish to minimize their *** hope that this work demonstrates the potential of pedestrian dynamics simulations in assessing preventative measures during pandemics,particularly if it is validated using empirical data.

关键词： pedestrian dynamics occupant exposure COVID-19 simulation study

The application of Fourier transform mid-infrared(FTIR) spectroscopy to identify variation in cell wall composition of Setaria italica ecotypes

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Journal of Integrative Agriculture 2017年第6期16卷 1256-1267页

作者： christopher Brown Antony P.Martin christopher P.L.Grof Centre for Plant Science School of Environmental and Life Sciences University of Newcastle Newcastle 2308 Australia Light Sheet Microscopy Unit Hunter Medical Research Institute Newcastle 2305 Australia

Cell wall composition in monocotyledonous grasses has been identified as a key area of research for developing better feedstocks for forage and biofuel *** viridis and its close domesticated relative Setaria italica have been chosen as suitable monocotyledonous models for plants possessing the C4 pathway of photosynthesis including sorghum,maize,sugarcane,switchgrass and Miscanthus×*** partial least squares regression（PLSR）models to predict *** stem composition have been generated,based upon Fourier transform mid-infrared（FTIR）spectra and calibrated with wet chemistry determinations of ground *** stem material measured using a modified version of the US National Renewable Energy Laboratory（NREL）acid hydrolysis *** models facilitated a high-throughput screening analysis for glucan,xylan,Klason lignin and acid soluble lignin（ASL）in a collection of 183 natural *** variants and clustered them into classes,some possessing unique *** predictive models provide a highly efficient screening tool for large scale breeding programs aimed at identifying lines or mutants possessing unique cell wall *** encoding key catalytic enzymes of the lignin biosynthesis pathway exhibit a high level of conservation with matching expression profiles,measured by RT-q PCR,among accessions of ***,which closely mirror profiles observed in the different developmental regions of an elongating internode of *** by RNASeq.

关键词： monocotyledonous C4 grasses lignin biosynthesis Fourier transform mid-infrared spectroscopy Setaria italica

mTORC1 signaling:what we still don’t know

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Journal of Molecular Cell Biology 2011年第4期3卷 206-220页

作者： Xuemin Wang christopher G.Proud School of Biological Sciences Life Sciences BuildingUniversity of SouthamptonSouthampton SO171BJUK

The mammalian target of rapamycin(mTOR)is a protein kinase that plays key roles in cellular *** forms complexes with additional *** best-understood one is mTOR complex 1(mTORC1).The regulation and cellular functions of mTORC1 have been the subjects of intense study;despite this,many questions remain to be *** include questions about the actual mechanisms by which mTORC1 signaling is stimulated by hormones and growth factors,which involves the small GTPase Rheb,and by amino acids,which involves other GTPase *** control of Rheb and the mechanism by which it activates mTORC1 remain incompletely *** it has been known for many years that rapamycin interferes with some functions of mTORC1,it is not known how it does this,or why only some functions of mTORC1 are ***1 regulates diverse cellular *** mTORC1 substrates are now known,although in several cases their physiological roles are poorly or incompletely *** the case of several processes,although it is clear that they are regulated by mTORC1,it is not known how mTORC1 does ***,mTORC1 is implicated in ageing,but again it is unclear what mechanisms account for *** the importance of mTORC1 signaling both for cellular functions and in human disease,it is a high priority to gain further insights into the control of mTORC1 signaling and the mechanisms by which it controls cellular functions and animal physiology.

关键词： mTORC1 protein synthesis cell signaling transcription cell growth autophagy metabolism

Development of a new algorithm for implementing the edge effect offset for subsidence calculations

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International Journal of Mining Science and Technology 2018年第1期28卷 61-66页

作者： Joshua Hescock christopher Newman Zach Agioutantis Department of Mining Engineering University of Kentucky

The surface deformation prediction system(SDPS) program has been developed as an engineering tool for the calculation of subsidence deformation indices through the implementation of various prediction *** basic user-defined input parameters, SDPS can determine subsidence indices, such as mining induced displacements, strains, tilt, etc., at any elevation between the seam and the horizontal or varying surface topography.A fundamental parameter in obtaining reliable ground deformation results is the determination of the edge effect *** value assigned to the edge effect offset corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined-out *** objective of this paper is to describe the methods implemented in updating the edge effect offset algorithm within *** proven geometric equations, the newly developed algorithm provides a more robust calculation of the offset boundary of the extracted panel for simplistic as well as more complex mining *** that an extracted panel is represented by a closed polyline, the new edge offset algorithm calculates a polyline offset into the extracted panel with respect to the user defined edge effect offset *** deformations are then calculated using this adjusted panel *** Matlab program was utilized for development and testing of the new edge effect offset *** completing rigorous testing regimes, the new offset algorithm will be integrated into SDPS further increasing the speed and reliability of the program resulting in a retrospective increase in capability and flexibility.

关键词： Subsidence Coal mining Influence function Edge effect

Influence of residual stresses on failure pressure of cylindrical pressure vessels

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Chinese Journal of Aeronautics 2013年第6期26卷 1415-1421页

作者： M.Jeyakumar T.christopher Department of Mechanical Engineering Sardar Raja College of EngineeringAlangulamTirunelveli 627 808India Department of Mechanical Engineering Government College of EngineeringTirunelveli 627 007India

The utilization of pressure vessels in aerospace applications is *** this work,fnite element analysis（FEA）has been carried out using ANSYS software package with 2D axisymmetric model to access the failure pressure of cylindrical pressure vessel made of ASTM A36 carbon steel having weld-induced residual *** fnd out the effect of residual stresses on failure pressure,frst an elasto-plastic analysis is performed to fnd out the failure pressure of pressure vessel not having residual *** a thermo-mechanical fnite element analysis is performed to assess the residual stresses developed in the pressure vessel during *** one more elasto-plastic analysis is performed to assess the effect of residual stresses on failure pressure of the pressure vessel having residual *** analysis indicates reduction in the failure pressure due to unfavorable residual stresses.

关键词： Aerospace engineering ASTM A36 Finite element analysis Pressure vessels Welding residual stress