检索结果-南通市图书馆

Biomass Production of Monocultures and Mixtures of Cup Plant and Native Grasses on Prime and Marginal Cropland

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2019年第6期10卷 911-924页

作者： Arvid Boe kenneth A. Albrecht Paul J. johnson Jixiang Wu Department of Agronomy Horticulture and Plant Science South Dakota State University Brookings SD USA Department of Agronomy University of Wisconsin Madison WI USA Insect Biodiversity Laboratory South Dakota State University Brookings SD USA

To date, most candidate systems for producing herbaceous cellulosic biomass have been composed of monocultures of perennial or annual grasses. Ecosystem goods and services provided from these biomass feedstock production systems could be increased dramatically with mixing of one or more forb species that would increase biodiversity and provide habitat for pollinators. Cup plant (Silphium perfoliatum L.) is featured with many desirable characteristics, such as high biomass potential, adaptation to marginal soils, and attractiveness to pollinators, desirable in a dicot species to grow in mixtures with perennial warm-season grasses. The objective of this study was to compare cup plant, switchgrass (Panicum virgatum L.), and prairie cordgrass (Spartina pectinata Link) monocultures to their mixtures for biomass production on prime and poorly drained marginal crop land for two years in both South Dakota and Wisconsin. In Wisconsin, monocultures of prairie cordgrass and cup plant and their mixture produced more biomass (8.1 Mg·ha-1) than the switchgrass monoculture and switchgrass/cup plant mixture (5.3 Mg·ha-1) on both prime and marginal land. While in South Dakota, drought and meristem destruction by the cup plant moth (Eucosma giganteana Riley) caused large reductions in biomass production (1.7 Mg·ha-1) in both years, with the switchgrass/cup plant mixture on marginal land having the highest yield (2.1 Mg·ha-1). Our study showed binary mixtures of cup plant and native warm-season grasses have great potential for increasing biodiversity and other ecosystem goods and services, relative to monocultures, for sustainable biomass feedstock production on poorly drained marginal land in the northcentral USA.

关键词： Silphium perfoliatum L. Switchgrass Panicum virgatum L. Prairie Cordgrass Spartina pectinata Link Bioenergy Pollinators Eucosma giganteana Riley Ecosystem Goods and Services

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Lakoff和johnson的体验哲学

当代语言学 2002年第2期4卷 144-151页

作者： Lakoff johnson 王寅苏州大学外国语学院江苏苏州215006

1.引言Lakoff和johnson合作出版了(1980)之后,于1999年又出版了另一本著作:(Philosophy in theFlesh--The Embodied Mind and Its Challenge to Western Thought,以下简称).书中提出了一个全新的哲学理论:体验哲学,论述了体验哲学的三项基本原则:'心智的体验性'、'认知的无意识性'和'思维的隐喻性'(the embodied mind, the cognitive un-consciousness, the metaphorical thought),并认为认知语言学是以体验哲学为其哲学基础的1.

关键词：体验哲学隐喻心智著作身体 99年挑战西方思想出版

Greenhouse gases fluxes and soil thermal properties in a pasture in central Missouri

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2010年第7期22卷 1029-1039页

作者： Nsalambi Vakanda Nkongolo Shane johnson Kent Schmidt Frieda Eivazi Department of Agriculture and Environmental Sciences College of Agriculture and Natural Science Lincoln University Harvard Forest Faculty of Arts and Sciences Harvard University

Fluctuations of greenhouse gases emissions and soil properties occur at short spatial and temporal scales, however, results are often reported for larger scales studies. We monitored CO2, CH4, and N2O fluxes and soil temperature （T）, thermal conductivity （K）, resistivity （R） and thermal diffusivity （D） from 2004 to 2006 in a pasture. Soil air samples for determination of CO2, CH4 and N2O concentrations were collected from static and vented chambers and analyzed within two hours of collection with a gas chromatograph. T, K, R and D were measured in-situ using a KD2 probe. Soil samples were also taken for measurements of soil chemical and physical properties. The pasture acted as a sink in 2004, a source in 2005 and again a sink of CH4 in 2006. CO2 and CH4 were highest, but N2O as well as T, K and D were lowest in 2004. Only K was correlated with C02 in 2004 while T correlated with both N2O （r = 0.76, p = 0.0001） and CO2 （r = 0.88, p = 0.0001） in 2005. In 2006, all gases fluxes were significantly correlated with T, K and R when the data for the entire year were considered. However, an in-depth examination of the data revealed the existence of month-to-month shifts, lack of correlation and differing spatial structures. These results stress the need for further studies on the relationship between soil properties and gases fluxes. K and R offer a promise as potential controlling factors for greenhouse gases fluxes in this pasture.

关键词： greenhouse gases soil thermal properties fluxes

Accelerated carbonation and leaching behavior of the slag from iron and steel making industry

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2007年第4期14卷 297-301页

作者： Quanyuan Chen johnson Lingyun Zhu Menghong Yuan Hills School of Environmental Science and Engineering Donghua University Shanghai 200051 China School of Science University of Greenwich Chatham Maritime Kent ME4 4TB UK School of Information Science and Technology Donghua University Shanghai 200051 China

Ground granulated blast furnace slag （GGBFS） and steelmaking slag have been used as a raw material for cement production or as an aggregate to make concrete, which contribute aluminum, calcium, iron, and silicon oxides. The suitability of the slag for a particular application depends on its reactivity, cost, availability, and its influence on the properties of the resulting concrete. For the interest of durability studying of concrete in the presence of slag, the accelerated carbonation products and leaching behavior of the slag and Portland cement （PC） were studied. The experimental results confirmed that the slag was more resistant to carbonation compared to PC. The carbonation degree of GGBFS reduced by 17.74%; and the carbonation degrees of steelmaking slags reduced by 9.51%- 11.94%. Carbonation neutralized the alkaline nature of the hydrated pastes and gave rise to the redox potential of the leachate slightly （30-77 mV）. The carbonation also increased the release of most of the elements presented, except for calcium, to the aqueous environment. It is concluded that blend cements （PC plus slag） have economical advantages and better durability compared to PC,

关键词： carbonation slag cement leachate durability

Effectiveness of a fixed-depth sensor deployed from a buoy to estimate water-column cyanobacterial biomass depends on wind speed

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2020年第7期32卷 23-29页

作者： Justin D.Chaffin Douglas D.Kane Alex johnson F.T Stone Laboratory and Ohio Sea Grant the Ohio State UniversityOH 43456USA Division of Natural Science Applied Scienceand MathematicsDefiance CollegeDefiance OHF.T Stone LaboratoryThe Ohio State University and Ohio Sea GrantOH 43456USA

Water quality sondes have the advantage of containing multiple sensors,extended deployment times,high temporal resolution,and telecommunication with stakeholder accessible data ***,sondes that are part of buoy deployments often suffer from typically being fixed at one *** water treatment plants are interested in water quality at a depth of the water intake and other stakeholders(*** and swimmers)are interested in the surface,we examined whether a fixed depth of approximately 1 m could cause over-or under-estimation of cyanobacterial *** sampled the vertical distribution of cyanobacteria adjacent to a water quality sonde buoy in the western basin of Lake Erie during the summers of 2015–2017.A comparison of buoy cyanobacteria RFU(Relative Fluorescence Unit)at 1 m to cyanobacteria chlorophyll a(chla)measured throughout the water column showed occurrences when the buoy both under and overestimated the cyanobacteria chl a at specific *** differences between buoy measurements and at-depth grab samples occurred during low wind speeds(4.5 m/sec)resulted in better agreement between the buoy and at-depth *** wind speeds 12 hr before sample collection decreased the difference between the buoy and at-depth samples for high wind speeds but not low *** suggest that sondes should be placed at a depth of interest for the appropriate stakeholder group or deploy sondes with the ability to sample at various depths.

关键词： Buoyancy Harmful algal bloom Lake Erie Microcystis Water quality

On the Forcing of the Radial-vertical Circulation within Cyclones-Part 1: Concepts and Equations

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1998年第3期15卷 64-85页

作者： D.R.johnson Space Science and Engineering Center University of Wisconsin-Madison Madison USA

お? Following the theoretical result of Eliassen, the Sawyer-Eliassen equation for frontal circulations and the equation for forcing the meridional circulation within a circumpolar vortex are extended in isentropic coordinates to describe the forcing of the azimuthally averaged mass-weighted radial-vertical circulation within translating extratropical and tropical cyclones. Several physical processes which are not evident in studies employing isobaric coordinates are isolated in this isentropic study. These processes include the effects of pressure torque, inertial torque and storm translation that are associated with the asymmetric structure in isentropic coordinates. This isentropic study also includes the effects of eddy angular momentum transport, diabatic heating and frictional torque that are common in both isentropic and isobaric studies. All of the processes are modulated by static, inertial and baroclinic stabilities.  Consistent with the theoretical result of Eliassen, the numerical solution from this isentropic study shows that the roles of torque, diabatic heating and hydrodynamic stability in forcing the radial-vertical circulation within stable vortices are that 1) positive (negative) torque which results in the counterclockwise (clockwise) rotation of vortices also forces the outflow (inflow) branch of the radial-vertical circulation, 2) diabatic heating (cooling) forces the ascent (descent) branch of the radial-vertical circulation and 3) for given forcing, the weaker hydrodynamic stability results in a stronger radial-vertical circulation. It is the net inflow or convergence (net outflow or divergence), vertical motions and the associated redistribution of properties that favor the evolution of vortices with colorful weather events.  Numerical solutions of this isentropic study are given in companion articles. The relatively important contribution of various physical processes to the forcing of the azimuthally-averaged mass-weighted radial-

关键词： The forcing of the radial-vertical circulation Quasi-Lagrangian diagnostics of cyclones,Balanced equation

Analysis of Social Media Impact on Stock Price Movements Using Machine Learning Anomaly Detection

在线全文

学校读者我要写书评

暂无评论

Intelligent Automation & Soft Computing 2023年第6期36卷 3405-3423页

作者： Richard Cruz johnson Kinyua Charles Mutigwe College of Information Sciences and Technology Pennsylvania State UniversityState CollegePA16801USA Western New England University College of Business1215 Wilbraham RdSpringfieldMA01119USA

The massive increase in the volume of data generated by individuals on social media microblog platforms such as Twitter and Reddit every day offers researchers unique opportunities to analyze financial markets from new *** meme stock mania of 2021 brought together stock traders and investors that were also active on social *** mania was in good part driven by retail investors’discussions on investment strategies that occurred on social media plat-forms such as Reddit during the COVID-19 *** stock trades by these retail investors were then executed using services like *** this paper,machine learning models are used to try and predict the stock price movements of two meme stocks:GameStop($GME)and AMC Entertainment($AMC).Two sentiment metrics of the daily social media discussions about these stocks on Red-dit are generated and used together with 85 other fundamental and technical indi-cators as the feature set for the machine learning *** is demonstrated that through the use of a carefully chosen mix of a meme stock’s fundamental indica-tors,technical indicators,and social media sentiment scores,it is possible to pre-dict the stocks’next-day closing ***,using an anomaly detection model,and the daily Reddit discussions about a meme stock,it was possible to identify potential market manipulators.

关键词： Machine learning deep learning anomaly detection Reddit r/walstreetbets meme stocks

Osteopontin: a leading candidate adhesion molecule for implantation in pigs and sheep

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 Animal Science and Biotechnology 2015年第2期6卷 177-190页

作者： Greg A johnson Robert C Burghardt Fuller W Bazer Department of Veterinary Integrative Biosciences Texas A&M UniversityCollege Station Department of Animal Science Texas A&M UniversityCollege Station

Osteopontin （OPN; also known as Secreted Phosphoprotein 1, SPP1） is a secreted extra-cellular matrix （ECM） protein that binds to a variety of cell surface integrins to stimulate cell-cell and cell-ECM adhesion and communication. It is generally accepted that OPN interacts with apically expressed integrin receptors on the uterine luminal epithelium （LE） and conceptus trophectoderm to attach the conceptus to the uterus for implantation. Research conducted with pigs and sheep has significantly advanced understanding of the role（s） of OPN during implantation through exploitation of the prolonged peri-implantation period of pregnancy when elongating conceptuses are free within the uterine lumen requiring extensive paracrine signaling between conceptus and endometrium. This is followed by a protracted and incremental attachment cascade of trophectoderm to uterine LE during implantation, and development of a true epitheliochorial or synepitheliochorial placenta exhibited by pigs and sheep, respectively. In pigs, implanting conceptuses secrete estrogens which induce the synthesis and secretion of OPN in adjacent uterine LE. OPN then binds to αvβ6 integrin receptors on trophectoderm, and the αvβ3 integrin receptors on uterine LE to bridge conceptus attachment to uterine LE for implantation. In sheep, implanting conceptuses secrete interferon tau that prolongs the lifespan of CL. Progesterone released by CL then induces OPN synthesis and secretion from the endometrial GE into the uterine lumen where OPN binds integrins expressed on trophectoderm （αvβ3） and uterine LE （identity of specific integrins unknown） to adhere the conceptus to the uterus for implantation. OPN binding to the αvβ3 integrin receptor on ovine trophectoderm cells induces in vitro focal adhesion assembly, a prerequisite for adhesion and migration of trophectoderm, through activation of： 1） P70S6K via crosstalk between FRAP1/MTOR and MAPK pathways; 2） MTOR, PI3K, MAPK3/MAPK1 （Erk1/2） and MAPK14 （p38） signalin

关键词： Implantation Integrins Psteoponti Pigs Sheep

Evolutionary diversity as a catalyst for biological discovery

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2018年第6期13卷 616-633页

作者： Zachary V.johnson Larry J.YOUNG School of Biological Sciences Georgia Institute of TechnologyAtlantaGeorgiaUSA Center for Translational Social Neuroscience Silvio O.Conte Center for Oxytocin and Social CognitionDepartment of Psychiatry and Behavioral SciencesYerkes National Primate Research CenterEmory UniversityAtlantaGeorgiaUSA

The tremendous diversity of animal behaviors has inspired generations of scientists from an array of biological *** complement investigations of ecological and evolutionary factors contributing to behavioral evolution,modern sequencing,gene editing,computational and neuroscience tools now provide a means to discover the proximate mechanisms upon which natural selection acts to generate behavioral *** behaviors are motivated behaviors that can differ tremendously between closely related species,suggesting phylogenetic plasticity in their underlying biological *** addition,convergent evolution has repeatedly given rise to similar forms of social behavior and mating systems in distantly related *** behavioral divergence and convergence provides an entry point for understanding the neurogenetic mechanisms contributing to behavioral *** argue that the greatest strides in discovering mechanisms contributing to social behavioral diversity will be achieved through integration of interdisciplinary comparative approaches with modern tools in diverse species *** review recent advances and future potential for discovering mechanisms underlying social behavioral variation;highlighting patterns of social behavioral evolution,oxytocin and vasopressin neuropeptide systems,genetic/transcriptional“toolkits,”modern experimental tools,and alternative species systems,with particular emphasis on Microtine rodents and Lake Malawi cichlid fishes.

关键词： cichlids oxytocin and vasopressin social behavior toolkits voles