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1.
2.
Sugarcane can be very susceptible to damage by freezes. Freeze-deteriorated cane can cause problems in processing and sometimes leads to a factory shut-down. This study was undertaken during the 2000/2001 harvest season to assess the cold tolerance performance of six commercial sugarcane varieties and to establish new and more sensitive criteria to measure cold tolerance. Two varieties CP 70-321 and CP 79-318, with known cold tolerance, were planted in the study as controls. The other varieties included LHo 83-153, LCP 85-384, HoCP 85-845 and HoCP 91-555. Freezing temperatures occurred on 20 December 2000 when the min. field temperature was −4.4 °C, and again on 21 December, 30 December through 5 January 2001, 9–10 January and 20–21 January. The lowest field temperature recorded was −5.6 °C on 4 January. Freezing conditions prevailed for 8–15 h during each freeze incident. Stalks of all varieties were frozen to the ground following the initial freeze, with freeze cracks evident only after the 4 January freeze. For this study, samples were taken on the date of the first freeze, 20 December, and subsequently again at 7, 14, 22 and 30 days after the first freeze. Criteria used to measure overall stalk cold-tolerance included changes in pH, Brix, dextran (ASI-II method), sucrose, glucose, and fructose concentrations. Mannitol, ethanol and the oligosaccharides, palatinose, leucrose, iso-maltotriose and 1-kestose, were simultaneuously measured using IC-IPAD. Marked differences were observed in most criteria for all varieties, particularly 22 and 30 days after the first freeze. Mannitol was strongly correlated (r2=0.84) with dextran, confirming its use as an indicator for cane dextran deterioration. In comparison, ethanol was only weakly correlated (r2=0.55) with dextran and did not always predict cane dextran deterioration. Iso maltotriose was the most sensitive oligosaccharide indicator of freeze deterioration, although both leucrose and palatinose could be used to confirm whether severe dextran formation (>1500 ppm/Brix) has occurred in cane. Isomaltotriose was strongly correlated (r2=0.89) with dextran and pH (r2=−0.83); pH was also a strong indicator of both dextran (r2=−0.85) and mannitol (r2=−0.92) formation. Four of the varieties, CP 79-318, LCP 85-384, HoCP 85-845 and HoCP 91-555, were shown to be susceptible to other sources of microbial and enzymic deterioration as well as dextran deterioration from Leuconostoc bacteria, especially 30 days after the first freeze. This was indicated by increased glucose/fructose ratios, ethanol formation, changes in 1-kestose concentration, and further sucrose losses. 相似文献
3.
Gillian Allard 《AI & Society》2003,17(1):12-24
The power of some new entrants to the music industry derives from their position as brokers in computer-mediated environments.
Brokers act instrumentally to exploit their position within a network which, in turn, depends on their ability to build and
sustain links (and, in computer-mediated environments, hyperlinks). Bricolage in computer-mediated entrepreneurship refers
to the intuitive manipulation of resources in order to achieve (perhaps tacit) goals. Without careful stewardship of the new
intellectual wealth thus created, bricolage may profit neither the individual nor the wider community.
Accepted 14 March 2002 相似文献
4.
Christopher L Brown Gillian Bushell Michael W Whitehouse DS Agrawal SG Tupe KM Paknikar Edward RT Tiekink 《Gold bulletin》2007,40(3):245-250
Nanosized gold particles (27 +/− 3 nm) have been proven to be effective in ameliorating the symptoms of mycobacterial-, collagen-
and pristane-induced arthritis in rat models. This contrasts with the drug sodium aurothiomalate that was only effective against
mycobacterial-induced arthritis but not to the same extent as Au0. Gold in the traditional Indian Ayurvedic medicine,Swarna bhasma (gold ash), has been characterized as globular particles of gold with an average size of 56–57 nm. 相似文献
5.
M. S. J. Simmonds W. M. Blaney F. Delle Monache G. B. Marini Bettolo 《Journal of chemical ecology》1990,16(2):365-380
The antifeedant activity of a series of 21 chalcones, flavanes, and flavanones isolated from the generaLonchocarpus andTephrosia (Leguminosae) was assessed by behavioral and electrophysiological bioassays against larvae ofSpodoptera littoralis andS. exempta. The antifeedant activity is related to the molecular structure of the compounds, and possible modes of interaction with the insect taste receptors are discussed. 相似文献
6.
The behavioral and physiological effects of plant allelochemicals have been difficult to demonstrate; it is not often clear whether the compounds are deterrent, toxic, or both. In this study, we compared the qualitative and quantitative effects of several iridoid glycosides on a generalist lepidopteran herbivore,Spodoptera eridania (Noctuidae). Larval growth and survivorship and larval preference or avoidance were measured on artificial diets containing different iridoid glycosides at different concentrations. We also tested the toxicity/deterrence of these compounds. We found that iridoid glycosides retarded larval growth significantly at relatively low concentrations and that they were usually avoided in preference tests. The toxicity/ deterrence test did not always reflect the results of these other tests. The merits of using a variety of methods for determining deterrence and/or toxicity of plant allelochemicals are discussed. 相似文献
7.
Response of generalist and specialist insects to qualitative allelochemical variation 总被引:7,自引:0,他引:7
We examined the effects of a set of four biosynthetically related iridoid glycosides, aucubin, catalpol, loganin, and asperuloside, on larvae of a generalist,Lymantria dispar (Lymantriidae), the gypsy moth, and an adapted specialist, the buckeye,Junonia coenia (Nymphalidae). In general,L. dispar grew and survived significantly less well on artificial diets containing iridoid glycoside, compared to a control diet without iridoid glycosides. In choice tests, previous exposure to a diet containing iridoid glycosides caused larvae subsequently to prefer iridoid glycoside-containing diets even though they were detrimental to growth and survival. In contrast,J coenia larvae grew and survived better on diets with aucubin and catalpol, the two iridoid glycosides found in the host plantPlantago lanceolata (Plantaginaceae), than on diets with no iridoid glycoside or with loganin and asperuloside. The results of choice tests of diets with and without iridoid glycosides and between diets with different iridoid glycosides reflected these differences as well. These results are discussed in terms of (1) differences between generalists and specialists in their response to qualitative variation in plant allelochemical content, (2) the induction of feeding preferences, and (3) the evolution of qualitative allelochemical variation as a plant defense. 相似文献
8.
Eleven polyhydroxy alkaloids of plant origin were tested for anti-feedant effects against larvae of the lepidopteransSpodoptera littoralis, Spodoptera frugiperda, Heliothis virescens, andHelicoverpa armigera. Data from behavioral and electrophysiological investigations were correlated to reveal information on the mode of action of the antifeedants. The pyrrolidine DMDP was an effective antifeedant for all four species, whereas the piperidines fagomine and XZ-1 and the pyrrolizidine alexine were all ineffective as antifeedants. The activity of the pyrrolidines CYB-3 and DAB-1, the piperidines DNJ, DMJ, and BR1, and the bicyclic octahydroindolizine castanospermine varied among species. The investigation focuses on the structural similarities between some of the alkaloids and some common phagostimulatory sugars and illustrates a neural interaction involving the neurons that are differentially responsive to alkaloids and sugars. InS. littoralis, the neurons responding specifically to the alkaloids DMDP, DAB-1, and castanospermine and to the sugars fructose, sucrose, and glucose are more active when the compounds are applied singly than when an alkaloid and a sugar are applied together. The implications for the occurrence and functioning of different sugar receptor sites are discussed. 相似文献
9.
Kobeissy FH Sadasivan S Oli MW Robinson G Larner SF Zhang Z Hayes RL Wang KK 《Proteomics. Clinical applications》2008,2(10-11):1467-1483
The rapidly growing field of neuroproteomics has expanded to track global proteomic changes underlying various neurological conditions such as traumatic brain injury (TBI), stroke, and Alzheimer's disease. TBI remains a major health problem with approximately 2?million incidents occurring annually in the United States, yet no affective treatment is available despite several clinical trials. The absence of brain injury diagnostic biomarkers was identified as a significant road-block to therapeutic development for brain injury. Recently, the field of neuroproteomics has undertaken major advances in the area of neurotrauma research, where several candidate markers have been identified and are being evaluated for their efficacy as biological biomarkers in the field of TBI. One scope of this review is to evaluate the current status of TBI biomarker discovery using neuroproteomics techniques, and at what stage we are at in their clinical validation. In addition, we will discuss the need for strengthening the role of systems biology and its application to the field of neuroproteomics due to its integral role in establishing a comprehensive understanding of specific brain disorder and brain function in general. Finally, to achieve true clinical input of these neuroproteomic findings, these putative biomarkers should be validated using preclinical and clinical samples and linked to clinical diagnostic assays including ELISA or other high-throughput assays. 相似文献
10.
The paper addresses a notion of configuring systems, constructing them from specified component parts with specified sharing.
This notion is independent of any underlying specification language and has been abstractly identified with the taking of
colimits in category theory. Mathematically it is known that these can be expressed by presheaves and the present paper applies
this idea to configuration.
We interpret the category theory informally as follows. Suppose ? is a category whose objects are interpreted as specifications,
and for which each morphism u : X→Y is interpreted as contravariant ‘instance reduction’, reducing instances of specification Y to instances of X. Then a presheaf P: Set ?op represents a collection of instances that is closed under reduction. We develop an algebraic account of presheaves in which
we present configurations by generators (for components) and relations (for shared reducts), and we outline a proposed configuration
language based on the techniques. Oriat uses diagrams to express colimits of specifications, and we show that Oriat's category
Diag(?) of finite diagrams is equivalent to the category of finitely presented presheaves over ?.
Received May 1998 / Accepted in revised form August 2000 相似文献