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Constraints on treeline advance in a warming climate:a test of the reproduction limitation hypothesis

Journal of Plant Ecology 2018年第3期11卷 411-422页

作者： Dasvinder Kambo ryan K.Danby Department of Geography Queen’s University99 University AvenueKingstonOntario K7L 3N6Canada School of Environmental Studies Queen’s University99 University AvenueKingstonOntario K7L 3N6Canada

Aims Several mechanistic hypotheses have been developed to explain the existence of alpine treelines *** reproduction limita-tion hypothesis(RLH)postulates that reproductive processes such as seed production and dispersal are restricted in treeline envi-ronments,thereby limiting the establishment of new individuals in advance of extant *** its popularity,no study has tested this hypothesis in a comprehensive *** this experi-ment,we attempted to answer whether there are enough viable seeds being dispersed beyond treeline for sexually mediated tree-line advance,and what the implications of climate change might be on these *** We established 30 plots across two aspects(north ***)and three elevational habitats(forest,treeline and tundra)in a white spruce(Picea glauca)boreal forest-alpine tundra ecotone in south-west Yukon,*** each plot,tree characteristics,seed produc-tion and predispersal damage were ***,eight dispersal trays were positioned in each plot to measure seed rain,and germination trials with and without predation exclosures were constructed in a subset of plots to quantify dispersal and germina-tion *** Findings Results were highly variable both temporally and *** 2014,a mast year,69%of adult trees produced cones compared to 0.4%in the following *** density of trees in forest plots compared to treeline and tundra resulted in greater seed production at lower *** all plots,88%of seeds were damaged before dispersal or were not *** plots had significantly greater predispersal *** rain was greater in south-facing plots than north-facing *** than 2%of seeds produced on the landscape were dispersed into Tundra plots,located 50 m above *** was a net movement of seeds from the north-facing slope to the south at our study site,likely due to prevailing winds during the dispersal *** counts were more

关键词： altitudinal gradients treeline dynamics predispersal seed damage seed predation seed masts ecotones

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Hybridization and the species problem in conservation

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Current Zoology 2015年第1期61卷 206-216页

作者： Benjamin m. FITZPATRICK maureen E. ryan Jarrett R. JOHNSON Joel CORUSH Evin T. CARTER Ecology and Evolutionary Biology University of Tennessee Knoxville TN 37996 USA School of Environmental and Forest Sciences University of Washington Seattle WA 98195 USA Biology Department Western Kentucky University Bowling Green KY 42101 USA

most biologists recognize the ＂species phenomenon＂ as a real pattern in nature： Biodiversity is characterized by dis- continuities between recognizable groups classified as species. many conservation laws focus on preventing species extinction. However, species are not fixed. Discontinuities evolve gradually and sometimes disappear. Exactly how to define particular spe- cies is not always obvious. Hybridization between taxonomic species reminds us that species classification is not a perfect repre- sentation of nature. Classification is a model that is very useful, but not adequate in all cases. Conservationists often confront questions about how to apply species-based laws when hybridization confounds classification. Development of sophisticated techniques and nuanced interpretation of data in the basic study of species and speciation has exposed the need for deeper educa- tion in genetics and evolution for applied conservationists and decision makers. Here we offer a brief perspective on hybridiza- tion and the species problem in conservation. Our intended audience is conservation practitioners and decision-makers more than geneticists and evolutionary biologists. We wish to emphasize that the goals and premises of legislative classification are not identical to those of scientific classification. Sometimes legal classification is required when the best available science indicates that discrete classification is not an adequate model for the case. Establishing legal status and level of protection for hybrids and hybrid populations means choosing from a range of scientifically valid alternatives. Although we should not abandon species-based approaches to conservation, we must recognize their limitations and work to clarify the roles of science and values in ethical and legal decisions [Current Zoology 61 （1）： 206-216, 2015].

关键词： Hybridization Hybrid zone Conservation Genetics Policy Classification Delimitation

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Direct visualization of phase-matched efficient second harmonic and broadband sum frequency generation in hybrid plasmonic nanostructures

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Light(Science & Applications) 2020年第1期9卷 276-285页

作者： Zhe Li Brian Corbett Agnieszka Gocalinska Emanuele Pelucchi Wen Chen Kevin m.ryan Pritam Khan Christophe Silien Hongxing Xu Ning Liu Department of Physics and Bernal Institute University of LimerickLimerickIreland The School of Physics and Technology Institute for Advanced Studies and Center for Nanoscience and NanotechnologyWuhan UniversityWuhan 430072China Tyndall National Institute University College CorkCorkIreland Institute of Physics Ecole Polytechnique Federale de Lausanne(EPFL)CH1015 LausanneSwitzerland Department of Chemical Sciences and Bernal Institute University of LimerickLimerickIreland

Second harmonic generation and sum frequency generation(SHG and SFG)provide effective means to realize coherent light at desired frequencies when lasing is not easily *** have found applications from sensing to quantum optics and are of particular interest for integrated photonics at communication *** the footprints of nonlinear components while maintaining their high up-conversion efficiency remains a challenge in the miniaturization of integrated *** we explore lithographically defined AlGaInP nano(micro)structures/Al_(2)O_(3)/Ag as a versatile platform to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both narrow-and broadband infrared(IR)wavelength regimes(1300-1600 nm).The effective excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113 nm×250 nm,with a mode area on the deep subwavelength scale(λ2/135)at fundamental ***,we demonstrate direct visualization of SHG/SFG phase-matching evolution in the *** together with mode analysis highlights the origin of the improved SHG/SFG *** also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1μm diameter AlGaInP disks/Al_(2)O_(3)/Ag with a conversion efficiency of 14.8%mW^(−1) which is five times the SHG value using the narrowband IR *** both configurations,the hybrid plasmonic structures exhibit>1000 enhancement in the nonlinear conversion efficiency compared to their photonic *** results manifest the potential of developing such nanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications.

关键词： waveguide harmonic optics

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Solution of Liouville’s Equation for Uncertainty Characterization of the main Problem in Satellite Theory

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Computer modeling in Engineering & Sciences 2016年第3期111卷 269-304页

作者： ryan Weisman manoranjan majji Kyle T.Alfriend Research Aerospace Engineer Air Force Research LaboratoryAFRL/RVSV 3550 Aberdeen Ave.SEKirtland AFB87117 Assistant Professor Mechanical and Aerospace Engineering DepartmentUniversity at Buffalo318 Jarvis HallBuffaloNY14260 TEES Research Professor Aerospace Engineering DepartmentTexas A&M UniversityCollege StationTX77843-3141

This paper presents a closed form solution to Liouville’s equation governing the evolution of the probability density function associated with the motion of a body in a central force field and subject to *** is shown that the application of transformation of variables formula for mapping uncertainties is equivalent to the method of characteristics for computing the time evolution of the probability density function that forms the solution of the Liouville’s partial differential *** insights derived from the nature of the solution to Liouville’s equation are used to reduce the dimensionality of uncertainties in orbital element *** is demonstrated that the uncertainty propagation is fastest in the semi-major axis and the mean anomaly phase *** results obtained for uncertainty propagation for the two body problem are applied to investigate the uncertainty propagation in the presence of the J2 perturbation using a combination of osculating and mean element perturbation *** orbital uncertainty propagation calculations are validated using monte-Carlo results for several representative orbits.

关键词： Astrodynamics Uncertainty Quantification

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Proteome changes of porcine follicular fluid during follicle development

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Journal of Animal Science and Biotechnology 2020年第2期11卷 367-379页

作者： Victor m.Paes Shengfa F.Liao Jose R.Figueiredo Scott T.Willard Peter L.ryan Jean m.Feugang Department of Animal and Dairy Sciences Mississippi State University4025 Wise CenterPO Box 9815StarkvilleMississippi State MS 39762USA Laboratory of manipulation of Oocyte and Preantral follicles State University of CearáFortalezaCEBrazil

Background:Ovarian follicular fluid influences follicle and oocyte growth,but the fluctuation of its protein content during folliculogenesis has not been comprehensively *** we used a shotgun approach and bioinformatics analyses to investigate and compare the proteomes of porcine follicular fluid(pFF)obtained from small(mm),medium(4–6 mm)and large(>6–12 mm)***:Follicular fluid samples containing highest estrogen levels were selected as non-atretic from small(SNA:26.1±15 ng/mL),medium(mNA:162±54 ng/mL),and large(LNA:290±37 ng/mL)follicles for proteomic *** detected 1627,1699,and 1756 proteins in SNA,mNA,and LNA samples,*** 60–63%of total proteins were specific to each sample,11–13%were shared in pairwise comparisons,and 247 proteins were shared among all *** categorization indicated comparable gene ontology(GO)terms distribution per cellular component,molecular function,and biological process categories across samples;however,the ranking of highly significantly enriched GO terms per category revealed differences between *** patterns of proteinto-protein interactions varied throughout follicle development,and proteins such as serine protease inhibitor,clade E(SERPINE);plasminogen activator,urokinase(PLAU);and plasminogen activator,urokinase receptor(PLAUR)appeared stage-specific to SNA,mNA,and LNA,***“complement and coagulation cascades”was the common major ***,properdin and fibulin-1 were abundant proteins that appeared absent in LNA ***:This study provides extensive and functional analyses of the pFF proteome changes during folliculogenesis and offers the potential for novel biomarker discovery in pFF for oocyte quality assessment.

关键词： Follicular fluid Folliculogenesis Pig Shotgun proteomic

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machine learning identification of symmetrized base states of Rydberg atoms

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Frontiers of physics 2022年第1期17卷 39-55页

作者： Daryl ryan Chong minhyuk Kim Jaewook Ahn Heejeong Jeong Department of Physics Faculty of ScienceUniversity of MalayaKuala Lumpur50603Malaysia Department of Physics KAISTDaejeon34141Korea

Studying the complex quantum dynamics of interacting many-body systems is one of the most challenging areas in modern physics. Here, we use machine learning (mL) models to identify the symmetrized base states of interacting Rydberg atoms of various atom numbers (up to six) and geometric configurations. To obtain the data set for training the mL classifiers, we generate Rydberg excitation probability profiles that simulate experimental data by utilizing Lindblad equations that incorporate laser intensities and phase noise. Then, we classify the data sets using support vector machines (SVms) and random forest classifiers (RFCs). With these mL models, we achieve high accuracy of up to 100% for data sets containing only a few hundred samples, especially for the closed atom configurations such as the pentagonal (five atoms) and hexagonal (six atoms) systems. The results demonstrate that computationally cost-effective mL models can be used in the identification of Rydberg atom configurations.

关键词： Rydberg atoms machine learning

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Statin use and cognitive function in middle-aged adults with type 1 diabetes

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World Journal of Diabetes 2017年第6期8卷 286-296页

作者： Karen A Nunley Trevor J Orchard Christopher m ryan Rachel miller Tina Costacou Caterina Rosano Department of Epidemiology University of PittsburghPA 15213United States

AIm To test associations between statin use and cognitive impairment in adults with childhood-onset type 1 diabetes(T1D).mETHODS In 2010-13, n = 108 middle-aged participants from ongoing observational Pittsburgh Epidemiology of Diabetes Complications Study underwent neurocognitive assessment(mean age and T1 D duration of 49 and 41 years, respectively). All were diagnosed with childhoodonset(i.e., prior to age 18) T1 D between 1950 and 1980 and were seen within one year of diagnosis at Children's Hospital of Pittsburgh. Self-reported statin use(yes/no and if yes, name of statin) was collected biennially from parent study baseline(1986-1988) to time of neurocognitive testing. Logistic regression models tested associations between statin use groups and cognitive impairment(defined as having two or more cognitive test scores 1.5SD or worse than published norms) while linear regression models tested associations between statin use groups and cognitive domain z-scores(domains: Verbal IQ, memory, executive function, psychomotor speed, and visuo-construction). All models controlled for education and age. To address confounding by indication, models were repeated using a propensity score for statin *** Of the 108 participants, 51 reported never using statins. median duration of statin use among the 57 ever users was 6 years. These 57 ever statin users were split to create two groups(≤ or > median years of statin use): 1-6 years(n = 25), and 7-12 years(n = 32). Compared with never users, using statins 1-6 years tripled the odds of cognitive impairment(OR = 3.16; 95%CI: 0.93-10.72; P = 0.06) and using statins 7-12 years almost quintupled the odds of cognitive impairment(OR = 4.84; 95%CI: 1.63-14.44; P = 0.005). Compared with never users, using statins 1-6 or 7-12 years was related to worse performance in the memory domain(β =-0.52; P = 0.003, and-0.39; P = 0.014, respectively). Adjusting for coronary artery disease, low density lipoprotein cholesterol, and Apo E4 statu

关键词： Type 1 diabetes Cognitive impairment memory Statin use Cohort study

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Evidence for colorectal sarcomatoid carcinoma arising from tubulovillous adenoma

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World Journal of Gastroenterology 2008年第27期14卷 4389-4394页

作者： Jeffrey K Lee Pradipta Ghosh Valerie mcWhorter misty Payne ryan Olson mary L Krinsky Sonia Ramamoorthy John m Carethers Department of medicine University of California San Diego California and Veteran Affairs medical Center San Diego Healthcare System Department of Pathology University of CaliforniaSan Diego California Department of Surgery University of California

Sarcomatoid carcinomas of the colorectum are rare tu- mors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrence, the pathogenesis is poorly understood. We report a case of a 52-year-old woman who presented with a rectal mass and intermittent hematochezia. Superficial biopsies during colonoscopy revealed a tubulovillous adenoma with high-grade dysplasia. Endoscopic ultra- sonography confirmed an invasive nature of the mass, and deeper biopsies revealed the presence of neoplasm with mixed histological components. The surgically- excised specimen demonstrated the presence of poorly differentiated spindle cells underneath the tubulovillous adenoma and an intermediate stage of invasive adeno- carcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcoma- toid carcinoma was made. Only nine cases of sarcoma- toid carcinomas of the colorectum have been reported to date. As a result, the terminology and pathogenesis of sarcomatoid carcinoma remain speculative. To the best of our knowledge, this is the first report of co- existence of sarcomatoid carcinoma and invasive ad- enocarcinoma with tubulovillous adenoma; all stages represented within the same tumor. This observation supports the "monoclonal theory" of pathogenesis with an adenoma-sarcoma progression with or without an intermediate stage of carcinoma.

关键词： Sarcomatoid carcinoma Tubulovillous adenoma Adenocarcinoma Rectum Cytokeratin

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Quiet in the nest:The nest environment attenuates song in a grassland songbird

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Avian Research 2023年第4期14卷 623-629页

作者： Sarah L.Dobney mikayla m.K.Bornais D.ryan Norris Amy E.m.Newman Heather Williams Stéphanie m.Doucet Daniel J.mennill Department of Integrative Biology University of WindsorWindsorOntarioN9B 3P4Canada Department of Integrative Biology University of GuelphGuelphOntarioN1G 2W1Canada Biology Department Williams CollegeWilliamstownMA01267USA

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside *** vocal learning species,such as humans and songbirds,it is vital for young animals to hear the voices of conspecific animals early in *** songbirds,nest structure varies considerably across species,and the resulting impact on sound transmission may have consequences for vocal learning in *** this study,we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows(Passerculus sandwichensis),grassland songbirds that build nests on the ground under cover of dense *** recorded live Savannah Sparrows singing at variable distances from 21 *** recorded songs using one microphone inside the nest(the typical position of a nestling)and another placed 1 m directly above the nest(a typical position of an adult).We found a substantial reduction in signal-to-noise ratio,where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the *** estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m(for recordings above the nest),to 78.6 m(for recordings within the nest),which is analogous to listening from a position 39.1 m farther away from the *** research estimated that song transmits up to 100 m in this species,so any adult male within 100 m of a young bird was previously considered a potential vocal *** reducing the nestling acoustic environment from 100 m to 78.6 m,the number of male tutors available to nestlings is reduced by an average of 27%.Given the growing evidence that song learning begins very early in life,future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

关键词： Acoustic environment Nest environment Songbird Sound attenuation Vocal learning

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流体-固体相互作用、碰撞和起飞的建模

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Acta mechanica Sinica 2023年第5期39卷 1-12页

作者： Frank T.Smith Ellen m.Jolley ryan A.Palmer Department of mathematics University College LondonLondonUK School of Biological Sciences University of BristolBristolEngland School of mathematics University of BristolBristolEngland

本文是流体-固体相互作用机制方面的最新进展综述,主要研究固体物体自身的运动与其周围流体运动之间的相互影响.非稳态相互作用的数学模型是对两个空间维度和时间尺度的内部通道和外部近壁流的描述.本文重点描述伴随计算量减少的分析发... 详细信息

本文是流体-固体相互作用机制方面的最新进展综述,主要研究固体物体自身的运动与其周围流体运动之间的相互影响.非稳态相互作用的数学模型是对两个空间维度和时间尺度的内部通道和外部近壁流的描述.本文重点描述伴随计算量减少的分析发展过程.文章讨论无黏性流中掠过和下沉、物体的起飞、飞离或弹跳,以及黏性效应,特别是黏性和无黏性之间的相互作用和影响.主要研究结果涉及撞击时间、起飞条件、撞击和飞离之间的边界、主要参数及其范围以及物体形状和质量对物理及力学机制的影响.

关键词： Fluid-body interactions Skimming Impacts Analysis

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