检索结果-南通市图书馆

Demographics, societal aging, and meat consumption in China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第6期14卷 995-1007页

作者： MIN Shi BAI Jun-fei James Seale jr. Thomas Wahl Institute of Development and Agricultural Economics Leibniz University Hannover College of Economics and Management China Agricultural University Department of Food and Resource Economics University of Florida Department of Agribusiness and Applied Economics North Dakota State University

Drawn on the data collected by surveying 1 340 urban households from six cities in China, this paper estimates the impacts of demographic structure and population aging on household meat consumption, by jointly considering meat consumed at home and away from home. Based on the trajectories of population, a simple simulation on meat demand trend in China is conducted subsequently. The results suggest： 1） Meat consumed away from home averagely accounts for near 30% of household total meat consumption in terms of quantity, so that its omission likely leads to a significant underestimate of total meat consumption and misunderstanding the driving forces; 2） population aging significantly and negatively affects per capita meat consumption, suggesting that the expected meat demand in China without considering population aging will be overestimated. The findings from this study have important implications for better understanding the relative issues on China＇s meat consumption under the situation of population aging.

关键词： capita household consumed income demographic jointly likely surveying estimates proportion

Lophozonia tree cavities used for nesting by Slender-billed Parakeets(Enicognathus leptorhynchus)in the central valley of southern Chile:a potentially vanishing keystone resource

在线全文

学校读者我要写书评

暂无评论

Chinese Birds 2017年第1期8卷 25-36页

作者： Thomas H.White jr. Jaime E.Jiménez Puerto Rican Parrot Recovery Program United States Fish and Wildlife ServiceBox 1600Rio GrandePR 00745USA Sub-Antarctic Biocultural Conservation Program Department of Biological SciencesUniversity of North TexasDentonTX 76201USA Sub-Antarctic Biocultural Conservation Program Department of Philosophy and ReligionUniversity of North TexasDentonTX 76201USA Omora Etnobotanical Park Universidad de MagallanesPuerto WilliamsChile

Background: The Slender-billed Parakeet(Enicognathus leptorhynchus) is a psittacine endemic to southern Chile and an obligate secondary cavity-nester. In the central valley of southern Chile, most(94%) of the known Slender-billed Parakeet nests have occurred in large, mature southern beech(Lophozonia obliqua) trees(locally known as "pellines"). As relicts of the original old-growth forests of southern Chile, most pellines have been lost due to extensive landclearing throughout the region, potentially threatening long-term persistence of the Slender-billed ***: We conducted our study in the central valley of southern Chile, near the city of Osorno during three consecutive nesting seasons(November–January, 2008–2011). Nest trees used by Slender-billed Parakeets were located by direct observation of parakeet activities and through interviews with local residents, some of whom were former parrot nest poachers. Nest cavities were accessed, inspected and measured using single-rope climbing techniques. We report means, standard errors, 95% confidence intervals and ranges for 11 cavity-related variables. We also report clutch sizes encountered in active nests, and age estimates of nest trees based on known growth rates of Lophozonia trees in southern Chile. Linear regressions were used to evaluate potential relationships between cavity-related variables and clutch ***: We located and measured 38 Lophozonia tree cavities used for nesting by Slender-billed Parakeets. Compared to those used by other psittacines, nest trees were relatively large, averaging 30.4 breast height of 134.5 ter ± 1.1 m in height with a mean diameter at ± 4.7 cm. Based on estimated annual diameincrement, ages of nest trees ranged from approximately 209–485 years. Nest cavities entrances averaged 12.5 ± 0.9 m in height above ground level. Cavity entrance widths averaged 51.0 ± 13.3 cm(vertical) by 11.5 ± 0.7 cm(horizontal). Cavity entrance orientations were apparently random, with

关键词： Conservation Deforestation Habitat loss Lophozonia obliqua Pellines Psittacidae Regeneration

Asynopsis of the book Ecological Indicators for the Nation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第4期13卷 520-523页

作者： JohnCairns jr. Department of Biology

Presents an excerpt from the book 'Ecological Indicators for the Nation,' by John Cairns jr.

关键词： ECOLOGY

Is Compositionality a Trivial Principle？

在线全文

学校读者我要写书评

暂无评论

Frontiers of Philosophy in China 2013年第1期8卷 140-155页

作者： Richard G. Heck, jr. Department of Philosophy Brown University Providence RI 02912 USA

Primarily a response to Paul Horwich＇s ＂Composition of Meanings,＂ this paper attempts to refute his claim that compositionality--roughly, the idea that the meaning of a sentence is determined by the meanings of its parts and how they are there combined--imposes no substantial constraints on semantic theory or on our conception of the meanings of words or sentences.

关键词： compositionality Horwich meaning semantics

Deformation‑Induced Strengthening Mechanism in a Newly Designed L‑40 Tool Steel Manufactured by Laser Powder Bed Fusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 21-34页

作者： Yuan Tian Kanwal Chadha Clodualdo Aranas jr Voestalpine Additive Manufacturing Centre Ltd MississaugaON L5N 7Y3Canada Department of Mechanical Engineering University of New BrunswickFrederictonNB E3B 5A3Canada Planetary and Space Science Centre University of New BrunswickFrederictonNB E3B 5A3Canada

The microstructural and mechanical properties of a newly designed tool steel(L-40),specifcally designed to be employed in the laser powder bed fusion(LPBF)technique,were *** pool boundaries with submicron dendritic structures and about 14%retained austenite phase were evident after *** grain orientation after high cooling rate solidifcation is mostlyα∥building direction(BD).Then,the heat treatment converted the microstructure into a conventional martensitic phase,reduced the retained austenite to about 1.5%,and increasedα∥BD *** heat-treated sample exhibits higher tensile strength(1720±14 MPa)compared to the as-printed sample(1540±26 MPa)along the building direction,mainly due to hardening caused by a lower volume fraction of retained austenite phase and precipitation of *** a consequence of the strength-to-ductility trade-of,the heat-treated sample showed lower elongation(10%±2%)than that of the as-printed sample(18%±2%).It was observed that transformation-induced plasticity(TRIP)occurs in both the as-printed and heat-treated samples during tensile testing,which dynamically transforms the retained austenite into martensite,leading to improved *** minimum driving force to initiate the displacive phase transformation is about 6000 J/mol,which was achieved during tensile *** strength and ductility of LPBF-produced L-40 were compared with the other LPBF-produced tool steels in literature;the data indicate that heat-treated L-40 has an excellent combination of strength and ductility complemented with high printability.

关键词： Additive manufacturing Laser powder bed fusion L-40 tool steel Phase transformation

Involuntary Unemployment： An Expository Note

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Economics in China-Selected Publications from Chinese Universities 2018年第1期13卷 83-92页

作者： Henry Y. Wan jr. Department of Economics Comell University Ithaca NY 14853 USA

This note is an effort to view the research program of Brecher and his co-workers to deploy tax incentives against involuntary unemployment in the broader context; on both the equity-efficiency trade-off in political ... 详细信息

关键词： involuntary unemployment efficiency wage wage rigidity

The aggressive invasion of exotic reptiles in Florida with a focus on prominent species： A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2011年第5期57卷 599-612页

作者： Richard ENGEMAN Elliott JACOBSON Michael L. AVERY Walter E. MESHAKA, jr. USDA/APHIS/Wildlife Services/National Wildlife Research Ctr 4101 LaPorte Ave. Fort Collins CO 80521-2154 USA College of Veterinary Medicine University of Florida Gainesville FL 32610 USA USDA/APHIS/Wildlife Services/National Wildlife Research Ctr 2820 East University Ave. Gainesville FL 32641 USA The State Museum of Pennsylvania 300 North Street Harrisburg Pennsylvania 17120 USA

Florida, along with Hawaii, has among the two worst invasive species problems in the USA, and the state is espe-cially susceptible to establishment by alien reptiles. Besides the large numbers of established non-native reptile species in Florida, many of these species present novel difficulties for management, or have other characteristics making effective management ex-tremely challenging. Moreover, initiation of management action requires more than recognition by experts that a potentially harmful species has become established. It also requires the political will along with concomitant resources and appropriate per-sonnel to develop effective methods and apply them. We review the situation in Florida, including assessment of risk for estab- lishment, and we use a subset of prominent species to illustrate in more detail the array of invasive reptile species circumstances in Florida, including routes of introduction, impacts, and potential and implemented management actions. These examples not only highlight the severity of the invasive reptile problems in the state, but they also show the diversity in resolve and response towards them and the motivating factors [Current Zoology 57 （5）： 599-612, 2011].

关键词： Argentine black and white tegus Biophysical ecology Burmese pythons Control Green and spiny-tailed iguanas,Invasive species Nile monitors Northern curlytail lizards

Preferential Bivalent Formation in Tetraploid Male of Pacific Oyster Crassostrea gigas Thunberg

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 Ocean University of China 2014年第2期13卷 297-302页

作者： ZHANG Zhengrui WANG Xinglian ZHANG Quanqi Standish Allen jr. College of Marine Life Sciences Key Laboratory of Marine Genetics and Breeding of Ministry of EducationOcean University of China Aquaculture Genetics and Breeding Technology Center Virginia Institute of Marine ScienceCollege of William and Mary

Artificially induced tetraploid Pacific oyster, Crassostrea gigas Thunberg, produces more aneuploid gametes than nor- mal diploid one, although they showed a comparable fecundity to diploidy. The meiotic chromosome configuration of 3 tetraploid and 1 tetraploid/triploid mosaic males were analyzed through direct chromosome observation. A majority of metaphase I spermato- cytes contained both bivalents and quadrivalents. The chromosome configuration of these males was characterized by preferential formation of bivalents to quadrivalents. Bivalents appeared in all spermatocytes and consisted of 86% of all chromosome aggregates. In comparison, quadrivalents occurred in 91% spermatocytes and consisted of only 12.6% of all chromosome aggregates. The mean bivalent frequency per spermatocyte varied between 14.4 and 17.2; while that of quadrivalents varied between 2.2 and 2.7. Most quadrivalents were tandemly chained （58%） or circled （39%）. The total number of chromosome aggregates per spermatocyte ranged from 13 to 20 with an average of 17.6; while 18 （16 bivalents and 2 quadrivalents） was the most frequent. Univalents and trivalents appeared in very low frequency. Aneuploid （hypotetraploid） spermatocytes were observed in a low frequency. The chromosome con- figuration of in the mosaic individual was similar to that of tetraploid individuals. The percentage of triploid spermatocytes （2%） of the mosaic individual was significantly lower （2＂2 =30, P〈 0.01） than that of triploid cells （46%） in its somatic tissue.

关键词： tetraploid oyster meiosis bivalent quadrivalent reversion

Detection of Arterial Occlusions Using Viscoelastic Wave Propagation

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2009年第1期1卷 1-28页

作者： H.T.Banks J.R.Samuels,jr. Center for Research in Scientific Computation North Carolina State UniversityCampus Box 8212RaleighNC 27695-8212USA

We consider the problem of detecting cardiac artery occlusions using stenosis driven viscoelastic(VE)waves propagated through biotissue to body surface *** investigate possible statistical model formulations(ordinary least squares(OLS),generalized least squares(GLS))and post analysis techniques(residual plots)to ascertain uncertainty in estimates as well as validity of the statistical models as part of a methodology for stenosis detection using viscoelastic waves.

关键词： Inverse problems viscoelastic models wave propagation in biotissue statistical models