5,290 research outputs found
Holocene environmental changes in Mongolia: A review
Holocene environmental change in Mongolia is reconstructed on the basis of recently published paleoclimate records, including lake levels, pollen assemblages, and eolian sediment records. These data indicate that the early Holocene of Mongolia is characterized by increasing temperature and humidity. Paleosol development, high lake-stands, and a more southward distribution of forest-steppe environments suggest the early-mid Holocene was humid. The mid-Holocene however is characterized by enhanced aridity, even though the onset and termination of the dry interval differs from place to place. Finally, humidity increased again during the late Holocene, as evaporation decreased in concert with dropping temperatures in Mongolia. © 2008 Elsevier B.V. All rights reserved
Gas Chromatographic-Mass Spectrometric Analysis of Essential Oil of Jasminum officinale L var Grandiflorum Flower
Purpose: To analyze the essential oil composition of the flower of Jasminum officinale L. var. grandifloroum L. (Jasminum grandiflorum) by gas chromatography-mass spectrometry (GC-MS).Methods: The optimum GC-MS conditions used for the analysis were 250 oC inlet temperature, 150 oC MSD detector temperature, and GC oven temperature program as follows: 100 oC initial temperature, increased to 270 oC at 4 oC/min, final temperature 270 oC and held for 7.5 min.Results: Thirty compounds were identified, representing 99.28 % of the oil content. The major volatile components of the flower were 3,7,11,15- tetramethyl-2-hexadecen-1-ol(phytol) (25.77 %), 3,7,11- trimethyldodeca -1,6,10-trien-3-ol (12.54 %) and 3,7,11,15- tetramethyl -1-Hexadecen-3-ol (12.42 %).Conclusion: The results show that phytol is the major volatile component of Jasminum grandiflorum.Keywords: Jasminum grandiflorum, Essential oil, Gas chromatography-mass spectrometr
Combined overexpression of chitinase and defensin genesin transgenic tomato enhances resistance to Botrytis cinerea
The rice chitinase gene (CHI), the alfalfa defensin gene (alfAFP) and their bivalent gene (CHI-AFP) were introduced into tomato line Micro-Tom via Agrobacterium-mediated gene transfer method. Transformants were obtained and confirmed by GFP, PCR and Southern blot hybridization. One to four copies of transgene were integrated into the tomato nuclear genome. Transcription levels of chitinase, alfAFP and their bivalent gene CHI-AFP in various transgenic lines were determined using Northern blotand Western blot analysis. Performance test of resistance analyses to Botrytis cinerea with T1 generation transgenic tomato lines showed the transgenic lines exhibited higher resistance to the pathogens infected than that of the non-transgenic plants and the resistance levels were related toexpression levels of the transgene, showing dosage-effect. The transgenic tomato harboring CHI-AFP cassette showed the highest disease resistance; it suggested that co-transformation with alfAFP and chitinase gene was more effective than individual transformations on the resistance to B. cinerea. Some independent lines with high disease resistance, low variability and stable expression of transgenes could be selected for the further studies and molecular breeding
Agricultural origins and the isotopic identity of domestication in northern China
Stable isotope biochemistry (δ 13C and δ 15N) and radiocarbon dating of ancient human and animal bone document 2 distinct phases of plant and animal domestication at the Dadiwan site in northwest China. The first was brief and nonintensive: at various times between 7900 and 7200 calendar years before present (calBP) people harvested and stored enough broomcorn millet (Panicum miliaceum) to provision themselves and their hunting dogs (Canis sp.) throughout the year. The second, much more intensive phase was in place by 5900 calBP: during this time both broomcorn and foxtail (Setaria viridis spp. italica) millets were cultivated and made significant contributions to the diets of people, dogs, and pigs (Sus sp.). The systems represented in both phases developed elsewhere: the earlier, low-intensity domestic relationship emerged with hunter-gatherers in the arid north, while the more intensive, later one evolved further east and arrived at Dadiwan with the Yangshao Neolithic. The stable isotope methodology used here is probably the best means of detecting the symbiotic human-plantanimal linkages that develop during the very earliest phases of domestication and is thus applicable to the areas where these connections first emerged and are critical to explaining how and why agriculture began in East Asia
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Airborne measurement of inorganic ionic components of fine aerosol particles using the particle-into-liquid sampler coupled to ion chromatography technique during ACE-Asia and TRACE-P
On the emergence of unaccusative 'give' constructions in Sinitic languages : a diachronic and typological perspective
The conference was organized by the International Association of Chinese Linguistics (IACL).Other Versio
Conditions for the emergence of unaccusative ‘give’ in Sinitic languages : evidence from Hui’an (Southern Min)
2011-2012 > Academic research: refereed > Refereed conference paperOther Versio
Relationship between climatic conditions and the relative abundance of modern C<inf>3</inf> and C<inf>4</inf> plants in three regions around the North Pacific
Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ13CTOC data from eastern China, Australia and the Great Plains of North America, we estimate the relative abundance of C3/C4 plants (i. e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg
Valence-changing phenomena and stance marking in Chinese : on the development of 共 in Classical Chinese and Southern Min
2013-2014 > Academic research: refereed > Refereed conference paperOther Versio
The saga of three mighty modals : a language learner’s guide to understanding how English must, may and can develop from deontic to epistemic uses
2011-2012 > Academic research: refereed > Refereed conference paperOther Versio
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