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Positive curvature, symmetry, and topology

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Frontiers of Mathematics in China 2016年第5期11卷 1099-1122页

作者： manuel AMANN Fakultat fur Mathematik Institut fiir Algebra und Geometrie Karlsruher Institut fiir Technologie Englerstraβe 2 76131 Karlsruhe Germany

We depict recent developments in the field of positive sectional curvature, mainly, but not exclusively, under the assumption of isometric torus actions. After an elaborate introduction to the field, we shall discuss various classification results, before we provide results on the computation of euler characteristics. This will be the starting point for an examination of more involved invariants and further techniques. In particular, we shall discuss the Hopf conjectures, related decomposition results like the Wilhelm conjecture, results in differential topology and index theory as well as in rational homotopy theory, geometrically formal metrics in positive curvature and much more. The results we present will be discussed for arbitrary dimensions, but also specified to small dimensions. This survey article features mainly depictions of our own work interest in this area and cites results obtained in different collaborations; full statements and proofs can be found in the respective original research articles.

关键词： Positive sectional curvature torus actions euler characteristic Hopf conjecture index theory Wilhelm conjecture geometric formality

The Professional Characteristics of Secondary Science Teachers to Students’ Academic effects:a Case of Bukidnonin the Philippines

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The Professional Characteristics of Secondary Science Teache...

作者： Reynaldo e.manuel.Jr. 华东师范大学

学位级别：硕士

本论文是一项旨在考察菲律宾Bukidnon地区中学科学教师的专业特征与该地区学生学业结果的调查研究。论文详细考察了受访者的个人和专业的履历,这些都在他们3到5年的职业生涯中对学生在学业表现方面产生了影响。为了提供一个有说服力的... 详细信息

本论文是一项旨在考察菲律宾Bukidnon地区中学科学教师的专业特征与该地区学生学业结果的调查研究。论文详细考察了受访者的个人和专业的履历,这些都在他们3到5年的职业生涯中对学生在学业表现方面产生了影响。为了提供一个有说服力的、客观的框架结构来考察和呈现论题,本研究采用了定量和定性相结合的方法进行数据收集。研究结果揭示了菲律宾Bukidnon地区中学科学教师在教师专业发展背景下缺乏学科知识、教育学、信息通讯技术应用于其他领域等方面的足够训练。对受访者的调查还发现,他们的教学负担过重,以至于没有时间进行学生辅导、家庭作业检查和阅读书籍。过去三年的全国成就测试(National Achievement Test)的结果,还呈现出一种令人担忧的下滑趋势,这也使得我们要反思受访者的专业特征情况。此外,研究还发现超过一半的受访者在过去的五年中未赢得过任何学术竞赛。因而,这正是论文努力要呈现的在督导视角下的学科现状。从这个角度,本论文期望能够有一个参照框架建立起政策与实践之间的桥梁,并引起教育部门政策制定者的足够重视。

关键词：专业特征学业结果学生成就科学教师中学全国成就测试(NAT) 菲律宾

Abiotic drivers shape seed inputs and outputs in a tropical wetland on Croton trinitatis population

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ecological Processes 2022年第1期11卷 65-77页

作者： Francielli Bao Arnildo Pott Pedro manuel Villa Centro de Avaliação da Biodiversidade Pesquisa e Conservação do Cerrado(CBC)Instituto Chico Mendes de Conservação da Biodiversidade(ICMBio)BrasíliaDF 70670-350Brazil Programa de Pós-Graduação em Biologia Vegetal Instituto de BiociênciasUniversidade Federal de Mato Grosso do SulCampo GrandeMS 79070-900Brazil Programa de Pós-Graduacão em Botânica Departamento de Biologia VegetalUniversidade Federal de ViçosaViçosaMG 36570-900Brazil Fundación para la Conservación de la Biodiversidad Mérida 7101Venezuela

Background:Predicting how natural and anthropogenic drivers shape different ecological indicators,such as plant populations along environmental gradients,can be a relevant tool for establishing management and conservation criteria of tropical wetlands.We aimed to assess the effects of seasonal flood disturbance,type of grasslands and topographical conditions on Croton trinitatis population distribution in a tropical wetland.Methods:The study was carried out in a seasonally flooded grassland(Central-West Brazil).We conducted samplings of soil on the dry and flood hydrophases of the Pantanal.We took the samples in eight seasonal ponds,with 1 km interval between them.Transects were marked during the flood period,observing the water level,one in the lowest zone,in the middle of the pond=low(ca.60 cm deep),one at the pond edge=mid(ca.30 cm deep)and one in the higher zone,on the external part=high(ca.1 cm deep).Results:The results showed that the topography,seasonality,and types of grassland determine differences in the abundance patterns of adult plants and seedlings,and seed bank and seed predation.The abiotic factors can shape plant population-related ecological processes and patterns,with outputs(germination and predation)and inputs(local dispersion and from neighbouring areas)of proportional seeds for the population maintenance in this environment.Conclusion:We emphasize the importance of these findings,to show that abiotic factors are not the only ones to be considered in ecological studies of distribution and structuring of populations in habitats with extreme seasonal events.

关键词： environmental filter Flood disturbance Pantanal Population ecology Seasonal change Seed predation Seedling Soil seed bank

Comparative mitogenome phylogeography of two anteater genera (Tamandua and Myrmecophaga;Myrmecophagidae, Xenarthra): evidence of discrepant evolutionary traits

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Zoological Research 2021年第5期42卷 525-547页

作者： manuel Ruiz-García Daniel Pinilla-Beltrán Oscar e.Murillo-García Christian Miguel Pinto Jorge Brito Joseph Mark Shostell Laboratorio de Genética de Poblaciones Molecular-Biología evolutiva Departamento de BiologíaFacultad de CienciasPontificia Universidad JaverianaBogotáDC 110231Colombia Grupo de Investigación en ecología Animal Departamento de BiologíaFacultad de Ciencias Naturales y ExactasUniversidad del ValleApartado AéreoCali 25360Colombia Instituto de Ciencias Biológicas Escuela Politécnica NacionalQuito 17012759Ecuador Instituto Nacional de Biodiversidad(INABIO) Quito 170135Ecuador Math Science and Technology DepartmentUniversity of Minnesota CrookstonCrookstonMN 56716USA

The species within Xenarthra(sloths,anteaters,and armadillos)are quintessential South American mammals.Of the three groups,Vermilingua(anteaters)contains the fewest extant and paleontological species.Here,we sampled and sequenced the entire mitochondrial genomes(mitogenomes)of two Tamandua species(Tamandua tetradactyla and T.mexicana)(n=74)from Central and South America,as well as Myrmecophaga tridactyla(n=41)from South America.Within Tamandua,we detected three different haplogroups.The oldest(THI)contained many specimens with the T.tetradactyla morphotype(but also several with the T.mexicana morphotype)and originated in southeastern South America(currently Uruguay)before moving towards northern South America,where the THII haplogroup originated.THII primarily contained specimens with the T.mexicana morphotype(but also several with the T.tetradactyla morphotype)and was distributed in Central America,Colombia,and ecuador.THI and THII yielded a genetic distance of 4%.THII originated in either northern South America or“in situ”in Central America with haplogroup THIII,which consisted of~50%T.mexicana and 50%T.tetradactyla phenotypes.THIII was mostly located in the same areas as THII,i.e.,Central America,ecuador,and Colombia,though mainly in the latter.The three haplogroups overlapped in Colombia and ecuador.Thus,T.tetradactyla and T.mexicana were not reciprocally monophyletic.For this reason,we considered that a unique species of Tamandua likely exists,i.e.,T.tetradactyla.In contrast to Tamandua,M.tridactyla did not show different morphotypes throughout its geographical range in the Neotropics.However,two very divergent genetic haplogroups(MHI and MHII),with a genetic distance of~10%,were detected.The basal haplogroup,MHI,originated in northwestern South America,whereas the more geographically derived haplogroup,MHII,overlapped with MHI,but also expanded into central and southern South America.Thus,Tamandua migrated from south to north whereas Myrmecophaga migrated from north to south.Our results also showed that tem

关键词： Anteaters Genetic diversity Mitogenomes Myrmecophaga Neotropics Phylogeography Spatial structure Tamandua

Peptides and Peptidomics: A Tool with Potential in Control of Plant Viral Diseases

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Advances in Microbiology 2014年第9期4卷 539-548页

作者： José Silvestre.mendoza-Figueroa manuel Soriano-García Laura Beatriz Valle-Castillo Jesús Méndez-Lozano Instituto de Química Universidad Nacional Autónoma de México Ciudad Universitaria Coyoacán Mexico City Mexico Instituto Politécnico Nacional CIIDIR Unidad Sinaloa Guasave Mexico

Plant viruses are the most infectious agents in commercially important crops worldwide. Plant viral diseases are important because both decreased yielding and quality of fruits, flowers or vegetables lead to million-dollar losses in production. At present there are no reports which suggest a direct control of plant virus. A new strategy for plant virus control has been raised since 13 years ago—the use of peptides. Peptides could offer a direct interaction by affinity selection against viral proteins involved in infection cycle, like capsid or movement protein (e.g.) and affect viral replication. Peptidomics, as a new tool to study peptides, led us screening and selecting the best peptide with antiviral activity, and re-designing it to enhance the biological effect as well as the potential of bioactivity of those peptides secreted by microbes present in soil. In this paper we review current aspects in the use of peptides and peptidomics as a strategy to study new methods that lead a direct control against plant viral diseases.

关键词： Peptidomics Plant Virus Peptides Peptaiboles Mass Spectrometry Aptamers

Acoustic streaming and Sun's meridional circulation

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Research in Astronomy and Astrophysics 2016年第9期16卷 101-106页

作者： Jose manuel Valverde Faculty of Physics University of Seville

A vast number of physical processes involving oscillations of a bounded viscous fluid are relevantly influenced by acoustic streaming. When this happens a steady circulation of fluid develops in a thin boundary adjacent to the interface. Some examples are refracted sound waves, a fluid inside a spherical cavity undergoing torsional oscillations or a pulsating liquid droplet. Steady streaming around circular interfaces consists of a hemispherically symmetric recirculation of fluid from the equatorial plane to the polar axes closely resembling the meridional circulation pattern observed in the Sun＇s convection zone that determines the solar cycle. In this paper, it is argued that the acoustic pulsations exhibited by the Sun would lead to acoustic streaming in the boundary of the convection zone. A simple estimation using a typical dominant frequency of 3 mHz and the observed surface oscillation amplitude yields a steady streaming velocity Us - 10 m s^-1, which is on the order of the meridional circulation velocity observed in the Sun＇s convection zone.

关键词： Sun general -- Sun helioseismology -- Sun granulation -- Sun oscillations -- Sun fun-damental parameters -- Sun activity

Anchor Root Development: A World within Worlds

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Molecular Plant 2020年第8期13卷 1105-1107页

作者： Josémanuel Pérez-Pérez Instituto de Bioingeniería Universidad Miguel Hernández03202 ElcheSpain

Many plant species develop shoot-borne adventitious roots(ARs)with specialized functions that contribute to plant adaptability by enhancing resource capture and stress avoidance.In Arabidopsis,as in many dicots,the postembryonic root system is primarily composed of lateral roots(LRs),which originate from the xylem pole pericycle cells through a process that involves periodic oscillation in gene expression mediated by a β-carotenoidderived signal(Dickinson et al.,2019).Our understanding of the key molecular and signaling events regulating AR initiation has recently been obtained from studies in Arabidopsis,where ARs are formed on etiolated hypocotyls upon transfer to light(Lakehal et al.,2019)or from excised leaf explants(Zhang et al.,2019).Anchor roots(ANRs)are a type of AR that originate immediately below the root-hypocotyl junction in an auxindependent manner and that require a diapocarotenoid-derived signal(anchorene)to emerge(Jia et al.,2019).ANR primordia activation may represent a generic mechanism to compensate for the loss of the growth potential of the primary root(PR),as it is enhanced by mutations affecting PR growth,by whole-root excision or by nitrogen deficiency(Jia et al.,2019).A recent paper by Bai et al.(2020)provides direct evidence that a regulatory module involving the AP2/eRF transcription factor ABSCISIC ACID INSeNSITIVe 4(ABI4),the mitogen-activated protein kinases(MAPKs)MPK3 and MPK6,and the phosphatase PP2C12 controls ANR emergence in Arabidopsis.

关键词： roots Arabidopsis Root

Open avenues for carotenoid biofortification of plant tissues

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Plant Communications 2023年第1期4卷 228-237页

作者： Luca Morelli manuel Rodriguez-Concepcion Institute for Plant Molecular and Cell Biology(IBMCP) CSIC-Universitat Polite`cnica de Vale`ncia46022 ValenciaSpain Department of Biology&CeSAM&eCOMARe Universidade de Aveiro3810-193 AveiroPortugal

Plant carotenoids are plastidial isoprenoids that function as photoprotectants,pigments,and precursors of apocarotenoids such as the hormones abscisic acid and strigolactones.Humans do not produce carotenoids but need to obtain them from their diet as precursors of retinoids,including vitamin A.Carotenoids also provide numerous other health benefits.Multiple attempts to improve the carotenoid profile of different crops have been carried out by manipulating carotenoid biosynthesis,degradation,and/or storage.Here,we will focus on open questions and emerging subjects related to the use of biotechnology for carotenoid biofortification.After impressive achievements,new efforts should be directed to extend the use of genome-editing technologies to overcome regulatory constraints and improve consumer acceptance of the carotenoid-enriched products.Another challenge is to prevent off-target effects like those resulting from altered hormone levels and metabolic homeostasis.Research on biofortification of green tissues should also look for new ways to deal with the negative impact that altered carotenoid contents may have on photosynthesis.Once a carotenoid-enriched product has been obtained,additional effort should be devoted to confirming that carotenoid intake from the engineered food is also improved.Thiswork involves ensuring post-harvest stability and assessing bioaccessibility of the biofortified product to confirm that release of carotenoids from the food matrix has not been negatively affected.Successfully addressing these challenges will ensure new milestones in carotenoid biotechnology and biofortification.

关键词： biofortification biotechnology carotenoids plastidial isoprenoids vitamin A

Autochthonous Hepatitis e Virus Infection in europe:A Matter of Concern for Public Health?

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Journal of Clinical and Translational Hepatology 2014年第1期2卷 7-14页

作者： José-manuel echevarría Department of Virology National Centre of Microbiology Instituto de Salud Carlos Ⅲ Madrid Spain

Human hepatitis e virus (HHeV) is the proposed name for a diverse group of RNA viruses from the family Hepeviridae that cause acute hepatitis among humans.Waterborne strains are regularly imported into europe by international travelers,and virus transmission of zoonotic strains via contaminated aliments is involved in autochthonous cases.Therefore,in europe,hepatitis e displays a unique dual character,having features of both imported and autochthonous infections.environmental involvement of waterborne and zoonotic diseases puts alimentary safety at risk.In addition,it may lead to serious health problems derived from persistent infection among patients with immune impairment due to organ transplant,cancer,or human immunodeficiency virus infection.Although the european health authorities know at present that HHeV represents a problem worthy of consideration,the actual incidence of the disease in europe is unknown,and attempts to ascertain the prevalence of the infection is hampered by unresolved technical issues.In order to determine the burden of hepatitis e in europe,the World Health Organization Regional Office and the european Centre for Disease Prevention and Control should pay specific attention to hepatitis e,and research efforts in the continent should be transnational and collaborative.Development of a specific european network for hepatitis e would help to achieve these goals.

关键词： Hepatitis Hepatitis e virus epidemiology europe Human