oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 37 )

2018 ( 259 )

2017 ( 265 )

2016 ( 355 )

Custom range...

Search Results: 1 - 10 of 194629 matches for " Claude D. Caldwell "
All listed articles are free for downloading (OA Articles)
Page 1 /194629
Display every page Item
用生态学思维重构传统农学学科:以农业生态系统管理作为核心应用科目
王松良,Claude D. Caldwell
中国生态农业学报 , 2013,
Abstract: 传统农学体系源于近代实验科学浪潮,并在工业革命巨大成就的推动下不断细分,失去对农业生态系统的整体把握。导致人类重新面临粮食安全(农业生态系统破坏引发的生产力衰退)和食品安全(农业环境破坏导致食物污染物残留)的双重危机。在我国,传统农学不论作为学科还是专业都属于生态系统以下的生物组织层次,是现代化石农业带来的生产和环境问题的根源。因此,农学学科及其专业教育体系的再构极为紧迫。作者提出以农业生态学为核心理论科目,以农业生态系统管理为核心应用科目而重构传统农学学科和教育体系。本文重点探讨了农业生态系统管理的基本框架和技术选择,并深入讨论了农业生态系统管理科目的内涵、外延及其发展前景。
Application of ecological thinking in reconstructing traditional agronomy: a case study of agro-ecosystem management as core applied subject
用生态学思维重构传统农学学科: 以农业生态系统 管理作为核心应用科目

WANG Song-Liang,Claude D CALDWELL,
王松良
,Claude D. Caldwell

中国生态农业学报 , 2013,
Abstract: The traditional agronomy was initiated at the tide of experimental science in modern agricultural academia. Because of the apparent achievements of Industrial Revolution, the comprehensive grasp of agro-ecosystem in understanding and developing agronomic science has subsequently not been recognized. As a consequence, humanity has to be confronted the double crises of food security resulting from the degradation of agro-ecosystems and productivity decline, and the food safety resulting from the deterioration of agro-environment and food contamination. Traditional agronomy has positioned bio-organizational levels under ecosystem scale both as a discipline and as a specialty in China. This has been the root of production and environmental problems in modern fossil agricultural practices. In this paper, we proposed reframing traditional agronomy by putting agro-ecology to core of theoretical system and agro-ecosystem management to core applied subject. The basic framework and technological choices of agro-ecosystem management were addressed in detail. Also the connotation, extension and development perspectives of agro-ecosystem management were discussed in detail.
农业生态系统服务及其管理学要义
祝文烽,王松良,Claude D Caldwell
中国生态农业学报 , 2010,
Abstract: 农业生态系统作为联系人类社会系统与自然生态系统的界面(Interface),其服务功能的健康发挥对整个农业系统稳定及人类生存与社会可持续发展具有现实和长远意义。本文综述了农业生态系统服务的研究现状、内涵与内容,从现有农业生态系统服务功能的量化评估指标和方法着手,提出了农业生态系统服务的量化难、研究技术相对滞后、研究机制缺位和研究力量薄弱成为农业生态系统服务研究的瓶颈,以及意识问题制约农业生态系统服务的研究进程等国内外研究中存在的主要问题,并展望了未来农业生态系统服务的研究趋势。最后,从概念层面、机制层面和技术层面提出促进农业生态系统服务功能健康发挥的管理学要义。
Agro-ecosystem service and its managerial essence
农业生态系统服务及其管理学要义

ZHU Wen-Feng,WANG Song-Liang,Claude D CALDWELL,
祝文烽
,王松良,Claude D Caldwell

中国生态农业学报 , 2010,
Abstract: 农业生态系统作为联系人类社会系统与自然生态系统的界面(Interface), 其服务功能的健康发挥对整个农业系统稳定及人类生存与社会可持续发展具有现实和长远意义。本文综述了农业生态系统服务的研究现状、内涵与内容, 从现有农业生态系统服务功能的量化评估指标和方法着手, 提出了农业生态系统服务的量化难、研究技术相对滞后、研究机制缺位和研究力量薄弱成为农业生态系统服务研究的瓶颈, 以及意识问题制约农业生态系统服务的研究进程等国内外研究中存在的主要问题, 并展望了未来农业生态系统服务的研究趋势。最后, 从概念层面、机制层面和技术层面提出促进农业生态系统服务功能健康发挥的管理学要义。
Plant Senescence: The Role of Volatile Terpene Compounds (VTCs)  [PDF]
Ernest Asante Korankye, Rajasekaran Lada, Sam Asiedu, Claude Caldwell
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.812211
Abstract: Senescence is a natural, energy-dependent, physiological, developmental and an ecological process that is controlled by the plant’s own genetic program, allowing maximum recovery of nutrients from older organs for the survival of the plant, as such; it is classified as essential component of the growth and development of plants. In some cases, under one or many environmental stresses, senescence is triggered in plants. Despite many studies in the area, less consideration has been given to plant secondary metabolites, especially the role of VTCs on plant senescence. This review seeks to capture the biosynthesis and signal transduction of VTCs, the physiology of VTCs in plant development and how that is linked to some phytohormones to induce senescence. Much progress has been made in the elucidation of metabolic pathways leading to the biosynthesis of VTCs. In addition to the classical cytosolic mevalonic acid (MVA) pathway from acetyl-CoA, the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, originating from glyceraldehyde-3-phosphate (GAP) and pyruvate, leads to the biosynthesis of isoprenoid precursors, isopentenyl diphosphate and dimethyl allyl diphosphate. VTCs synthesis and emission are believed to be tightly regulated by photosynthetic carbon supply into MEP pathway. Thus, under abiotic stresses such as drought, high salinity, high and low temperature, and low CO2 that directly affect stomatal conductance and ultimately biochemical limitation to photosynthesis, there has been observed induction of VTC synthesis and emissions, reflecting the elicitation of MEP pathway. This reveals the possibility of important function(s) of VTCs in plant defense against stress by mobilizing resources from components of plants and therefore,
Best Management Practices for Minimizing Nitrate Leaching from Container-Grown Nurseries
Jianjun Chen,Yingfeng Huang,Russell D. Caldwell
The Scientific World Journal , 2001, DOI: 10.1100/tsw.2001.99
Abstract:
An Inverted Mass Hierarchy for Hot Dark Matter and the Solar Neutrino Problem.
D. O. Caldwell,R. N. Mohapatra
Physics , 1995, DOI: 10.1016/0370-2693(95)00727-3
Abstract: The cosmological model in which 20% of the dark matter is shared by two nearly equal mass neutrinos fits the structure of the universe on all scales. This has been motivated a $\nu_\mu$-$\nu_{\tau}$ oscillation explanation of the deficit of atmospheric muon neutrinos. If the observed ratio of atmospheric $nu_\mu$ to $\nu_e$ has an alternative explanation, the cosmological model can be retained if the deficit of solar neutrinos is explained by $\nu_e$-$\nu_{\tau}$ oscillation. In this case an inverted mass hierarchy is required with $m_{\nu_{\mu}}\ll m_{\nu_e} \simeq m_{\nu_\tau}\approx 2.4$ eV. We show that if there exists an $L_e- L_{\tau}$ symmetry in nature, both the near mass degeneracy of \nue\ and \nut\ as well as the consistency of the above values for neutrino masses with the negative results for neutrinoless double beta decay search experiments are easily understood. We show that this symmetry implemented in the context of a high-scale left-right symmetric theory with the see-saw mechanism can lead to a simple theoretical understanding of the desired form of the mass matrix.
Further Evidence for Neutrino Flux Variability from Super-Kamiokande Data
D. O. Caldwell,P. A. Sturrock
Physics , 2003,
Abstract: While KamLAND apparently rules out Resonant-Spin-Flavor-Precession (RSFP) as an explanation of the solar neutrino deficit, the solar neutrino fluxes in the Cl and Ga experiments vary with solar rotation rates. Added to this evidence, summarized here, a power spectrum analysis of the Super-Kamiokande data reveals (99.9% CL) an oscillation in the band of twice the equatorial rotation frequencies of the solar interior. An m=2 magnetic structure and RSFP, perhaps as a subdominant process, would give this effect. Solar cycle data changes are seen, as expected for convection zone modulations.
Mechanical Shaking and Baling of Balsam Fir Trees Influence Postharvest Needle Senescence and Abscission  [PDF]
Ernest A. Korankye, Rajasekaran R. Lada, Samuel K. Asiedu, Claude Caldwell
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.93027
Abstract: This study investigated the influence of both shaking duration and number of trees per bale on postharvest needle characteristics such as percentage needle loss, needle retention duration and explored the physiological roles of endogenous ethylene and volatile terpene compounds (VTCs). To accomplish these objectives, 25 six-year-old trees were detached and exposed to a range of shaking durations (0 to 60 sec.), and 30 six-year-old detached trees were exposed to baling treatments from 0 to 5 trees. Response variables measured were percent needle loss, needle retention duration, average water use, ethylene and volatile terpene compound evolution. Trees shaken for 60 seconds lost 16% less needle compared to control, which was consistent with the decrease in percent needle loss with increasing shaking duration. Baled trees lost 13% more needles compared to control, but percent needle loss was observed to decrease with increasing number of trees in a bale. These trends corresponded with increasing ethylene and VTC evolutions, where the longer the shaking duration or larger number of trees in a bale, the higher the ethylene and VTC evolutions. One can therefore draw inference that mechanical perturbation as a result of shaking and baling induce biosynthesis and
Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization
Sa?d Barazzouk,Claude Daneault
Nanomaterials , 2012, DOI: 10.3390/nano2020187
Abstract: In this work, oxidized nanocellulose (ONC) was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl- N’-(3-dimethylaminopropyl) carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides) were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectroscopic techniques.
Page 1 /194629
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.