检索结果-南通市图书馆

Preliminary attempt to distinguish the domesticated pigs from wild boars by the methods of carbon and nitrogen stable isotope analysis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第1期52卷 85-92页

作者： michael P.RICHARDS Department of Human Evolution Max-Planck Institute for Evolutionary AnthropologyDeutscher Platz 6D-04103LeipzigGermany

Despite great achievements in the origins of domestic pigs made by the methods of zooarchaeology and molecular biology,how to scientifically distinguish the domesticated pigs from wild boars during the early stage of pig domestication is still poorly *** to wild boar's diets which come from the natural environment,the diets of domestic pigs are more easily influenced by human feeding ***,in principle,exploration of the dietary differences among pigs and understanding the impact on pig diets fed by humans can have great potential to differentiate between wild boars and domesticated *** reveal dietary differences among pigs and distinguish the domesticated pigs from wild boars based on comparison with the diets of humans and other animals,we analyzed the carbon and nitrogen stable isotopes of human bones from Xiaojingshan Site and animal bones from Yuezhuang Site,both of which belong to Houli Culture in Shandong Province and date to about 8500―7500 years *** mean δ 13C value((-17.8 ± 0.3)‰) and δ 15N value((9.0±0.6)‰) in human collagen indicate that although millet agriculture began it was not the main subsistence strategy as millets are typical of C4 plants and that humans made a living mainly by gathering,hunting or raising some domesticated *** δ 13C value(-16.1‰) and δ 15N value(6.9‰) in the bovine suggest that C3 plants were dominant in its diet with some C4 plants *** fish has lower δ 13C value(-24.9‰) and higher δ 15N value(8.8‰) than the bovine,which is the characteristic of the isotopic values from Eurasian freshwater *** on the differences in carbon and nitrogen isotope values,the pigs can be divided into three groups.A group,composed of two pigs,has low δ 13C values(-18.1‰,-20.0‰) and low δ 15N values(4.7‰,6.0‰).B group,only one pig,has the highest δ 13C value(-10.6‰) and mediate δ 15N value(6.4‰).As for the C group,also only one pig,low δ 13C value(-19.0‰) and the highest δ 15N value(9.1‰

关键词： origins of domestic pigs early stage of domestication differentiation of domesticated pigs from wild boars carbon and nitrogen stable isotope analysis millet agriculture

Massless and Massive Particle-in-a-Box States in Single- and Bi-Layer Graphene

在线全文

学校读者我要写书评

暂无评论

Nano Research 2011年第4期4卷 385-392页

作者： Sungjae Cho michael Fuhrer Department of Physics and Center for Nanophysics and Advanced Materials University of Maryland College Park Maryland 20742 USA

Electron transport through short, phase-coherent metal-graphene-metal devices occurs via resonant transmission through particle-in-a-box-like states defined by the atomically-sharp metal leads. We study the spectrum of particle-in-a-box states for single- and bi-layer graphene, corresponding to massless and massive two-dimensional （2-D） fermions. The density of states D as a function of particle number n shows the expected relationships D（n） -n1/2 for massless 2-D fermions （electrons in single-layer graphene） and D（n） -constant for massive 2-D fermions （electrons in bi-layer graphene）. The single parameters of the massless and massive dispersion relations are found, namely Fermi velocity vF = 1.1 × 10^6 m/s and effective mass m＊ = 0.032 me, where me, is the electron mass, in excellent agreement with theoretical expectations.

关键词： Fabry-Perot interference ballistic density of states phase-coherent

A detailed Lower Triassic conodont biostratigraphy and its implications for the GSSP candidate of the Induan–Olenekian boundary in Chaohu,Anhui Province

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第1期18卷 79-90页

作者： michael J.Orchard Canada V6B5J3 Geological Survey of Canada 101-605 Robson Street Vancouver

Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block,which belonged to the low-latitude eastern Tethyan archipelago during the Early *** were very rich in the Lower Triassic of ***,ammonoids,conodonts were very common throughout the Lower Triassic,while fish fossils were generally rich in some beds of the upper *** is one of the most typical sections for the Early Triassic chronostratigraphy in the *** various fossils had been studied in the 1980s and 1990s,recent studies based upon new and more detailed collections from the Lower Triassic of Chaohu showed that the conodont zonation needs *** collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan,North Pingdingshan and South Majiashan,Chaohu,Anhui Province,and updated zonations were made for each *** conodont zones have been dis- *** are,in ascending order,Hindeodus typicalis zone,Neogondolella krystyni zone,Neospathodus kummeli zone,Neospath- odus dieneri zone,Neospathodus waageni zone,Neospathodus pingdingshanensis zone,Neospathodus homeri zone,and Neospathodus anhuinensis *** first occurrence of Neospathodus waageni eowaageni of the *** subzone(*** base of the *** zone)is suggested as the marker to define the Induan–Olenekian boundary.

关键词： Conodont biostratigraphy Conodont zonation Lower Triassic Induan–Olenekian Chaohu in Anhui Province

Challenge of global climate change:Prospects for a new energy paradigm

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2010年第1期4卷 2-11页

作者： michael B.MCELROY School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences Harvard UniversityCambridgeMA 02138USA

Perspectives on the challenge posed by potential future climate change are presented including a discussion of prospects for carbon capture followed either by sequestration or reuse including opportunities for alternatives to the use of oil in the transportation *** potential for wind energy as an alternative to fossil fuel energy as a source of electricity is outlined including the related opportunities for cost effective curtailment of future growth in emissions of CO_(2).

关键词： climate change carbon capture wind ethanol CO_(2) radiative forcing

Explaining the “Pulse of Protoplasm”: The search for molecular mechanisms of protoplasmic streaming

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2015年第1期57卷 14-22页

作者： michael R.Dietrich Department of Biological Sciences Dartmouth College

Explanations for protoplasmic streaming began with appeals to contraction in the eighteenth century and ended with appeals to contraction in the twentieth. During the intervening years, biologists proposed a diverse array of mechanisms for streaming motions. This paper focuses on the re-emergence of contraction among the molecular mecha-nisms proposed for protoplasmic streaming during the twentieth century. The revival of contraction is a result of a broader transition from colloidal chemistry to a macro- molecular approach to the chemistry of proteins, the recognition of the phenomena of shuttle streaming and the pulse of protoplasm, and the influential analogy between protoplasmic streaming and muscle contraction.

关键词： Actin cytoplasmic streaming history of cell biology protoplasm

High-resolution flood modeling of urban areas using MSN_Flood

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2017年第3期10卷 175-183页

作者： michael Hartnett Stephen Nash Department of Civil Engineering National University of IrelandGalwayIreland

Although existing hydraulic models have been used to simulate and predict urban flooding, most of these models are inadequate due to the high spatial resolution required to simulate flows in urban floodplains. Nesting high-resolution subdomains within coarser-resolution models is an efficient solution for enabling simultaneous calculation of flooding due to tides, surges, and high river flows. MSN_Flood has been developed to incorporate moving boundaries around nested domains, permitting alternate flooding and drying along the boundary and in the interior of the domain. Ghost cells adjacent to open boundary cells convert open boundaries, in effect, into internal boundaries. The moving boundary may be multi-segmented and non-continuous, with recirculating flow across the boundary. When combined with a bespoke adaptive interpolation scheme, this approach facilitates a dynamic internal boundary. Based on an alternating-direction semi-implicit finite difference scheme,MSN_Flood was used to hindcast a major flood event in Cork City resulting from the combined pressures of fluvial, tidal, and storm surge processes. The results show that the model is computationally efficient, as the 2-m high-resolution nest is used only in the urban flooded ***, lower-resolution nests are used. The results also show that the model is highly accurate when compared with measured data. The model is capable of incorporating nested sub-domains when the nested boundary is multi-segmented and highly complex with lateral gradients of elevation and velocities. This is a major benefit when modelling urban floodplains at very high resolution.

关键词： Multi-scale nesting Surge-fluvial flooding Urban flooding Multi-segmented boundary Moving boundary

A simple human cell model for TAU trafficking and tauopathy-related TAU pathology

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2022年第4期17卷 770-772页

作者： michael Bell Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCenter for Molecular Medicine Cologne(CMMC)University of CologneCologneGermany

The microtubule(MT)-associated protein TAU is highly abundant in the axon of human brain neurons,where it binds to and stabilizes MT ***,TAU regulates the dynamic(dis)assembly of MT strands and is involved in a wide range of neuronal *** Alzheimer's disease(AD)and other tauopathies,TAU is missorted into the somatodendritic *** missorting is accompanied by(or leads to)abnormal TAU phosphorylation,MT destabilization,and loss of dendritic spines and mitochondria,eventually resulting in TAU aggregation,neuronal dysfunction and cell death(Arendt et al.,2016).Strikingly,the mechanisms of TAU sorting,and the detrimental cascade upon its failure,are still not fully understood.

关键词： tau sorting eventually

在线全文

学校读者我要写书评

暂无评论

Rethinking the egg

National Science Review 2024年第6期11卷 81-82页

作者： michael J.Benton School of Earth Sciences University of Bristol

Our image of early dinosaur eggs must change. Early dinosaur eggs are portrayed as soft-shelled, like those of modern lizards or snakes [1], and yet all the evidence is that early dinosaurs at least laid leathery-shel... 详细信息

关键词： rethinking

A primitive confuciusornithid bird from China and its implications for early avian flight

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第5期51卷 625-639页

作者： michael J. BENTON Department of Earth Sciences University of Bristol Bristol BS8 1RJ UK

Confuciusornithids, lived from 120–125 million years ago, form a basal bird group and include the oldest birds with horny beaks. Here we describe Eoconfuciusornis zhengi, gen. et sp. nov. from the Early Cretaceous Dabeigou Formatio (131 Ma) in Fengning, Hebei Province, northern China. It represents a new and, more primitive than other known, member of this group and extends the lifespan of this family to 11 Ma, the longest of any known Early Cretaceous avian lineages. Furthermore, Eoconfuciusornis and its relatives present many osteological transformations, such as the size increase of the deltopectoral crest of the humerus and the keel of the sternum, apparently an adaptation toward improved flight in the evolution of the Confuciusornithidae.

关键词： Birds Early Cretaceous confuciusornithids flight