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991.
992.
基于Median函数的分段回归模型及其在生物学上的应用 总被引:1,自引:0,他引:1
在生物学科研工作中,经常会遇到因变量和自变量之间存在着多种不同的趋势,分段回归模型可以很好的拟合变量间这种非线性趋势.本文介绍了基于Median函数的分段回归模型,可以同时对各项回归参数和转折点进行估计,最后,本文结合生物学上的实例运用SAS统计软件进行了分段回归模型的拟合. 相似文献
993.
通过福建省中亚热带杉木观光木混交林(Cunninghamia lanceolata and Tsoongiodendron odorum mixed forest)和杉木纯林(Pure C. lanceolata forest)凋落物的分解和养分释放动态试验研究表明,凋落物各组分分解过程中干物质损失速率随时间而减小,分解1年时以观光木叶的干重损失最大。各组分分解过程中N、P元素浓度增加而K和C元素浓度下降。混交林中各组分的养分释放速率大小为观光木叶>混合样品(等重量的观光木叶和杉木叶混合)>杉木叶>杉木 相似文献
994.
Toscano AE Amorim MA de Carvalho Filho EV Aragão Rda S Cabral-Filho JE de Moraes SR Manhaes-de-Castro R 《Life sciences》2008,82(21-22):1131-1136
Growth and development events are observed in all organisms and can be modified by exogenous factors such as nutritional changes. Drastic morphological and functional alterations may occur during a vulnerable stage of development. The aim of this study was to investigate if malnutrition and/or fluoxetine neonatal treatment program alterations in heart morphology during the postnatal period. The sample consisted of 48 albino Wistar male rats. The rats were divided into two groups: nourished and malnourished. Pharmacologic manipulation was performed during the suckling period. The animals of each group were divided into two subgroups: saline-nourished and saline-malnourished, treated with sodium chloride solution, and fluoxetine-nourished and fluoxetine-malnourished, treated with fluoxetine. Half of the individuals in each subgroup were weighed and sacrificed on day 30 and the other half on day 71. Myocardial perfusion was performed and the heart subsequently weighed. The ventricles were cross-sectioned into two parts, which were fixed, dehydrated and sectioned. There were differences in body weight, heart weight, cross-sectional area and perimeter of the heart and in the cross-sectional area and perimeter of the cardiac cells among the groups at the different ages. Malnutrition appears to program alterations in heart morphology. However, malnourished animals that had undergone drug treatment did not exhibit the same changes. 相似文献
995.
Previously, bio-mechanical studies on the temporomandibular joint have concentrated mainly on the mandibular condyle while the articular eminence has been largely overlooked. Furthermore, research on the mechanical properties of bone using finite element analysis has focused on the cortical bone in preference to cancellous bone. In this study morphorogical changes in the internal structure of the articular eminence as related to child growth were examined using Micro-CT. Morphometric analysis of samples of cancellous bone representing both deciduous and early mixed dentitions showed an increase in the bone volume fraction and trabecular thickness in the early mixed dentition, and finite element analysis indicated directional transmission of stress as well. These results suggest that the morphology of the trabecular bone was altered to adapt to the functional growth progressed from the deciduous to the early mixed dentition. 相似文献
996.
Logistics system design for biomass-to-bioenergy industry with multiple types of feedstocks 总被引:1,自引:0,他引:1
It is technologically possible for a biorefinery to use a variety of biomass as feedstock including native perennial grasses (e.g., switchgrass) and agricultural residues (e.g., corn stalk and wheat straw). Incorporating the distinct characteristics of various types of biomass feedstocks and taking into account their interaction in supplying the bioenergy production, this paper proposed a multi-commodity network flow model to design the logistics system for a multiple-feedstock biomass-to-bioenergy industry. The model was formulated as a mixed integer linear programming, determining the locations of warehouses, the size of harvesting team, the types and amounts of biomass harvested/purchased, stored, and processed in each month, the transportation of biomass in the system, and so on. This paper demonstrated the advantages of using multiple types of biomass feedstocks by comparing with the case of using a single feedstock (switchgrass) and analyzed the relationship of the supply capacity of biomass feedstocks to the output and cost of biofuel. 相似文献
997.
998.
滇南榆绿木群落的初步研究 总被引:9,自引:1,他引:9
滇南小橄榄坝地区的榆绿木(Anogeissus acuminata)群落是一种次生性质的单优群落,具有典型热带季雨林的外貌和结构特征。该群落是原生植被混交落叶季雨林破坏后发展起来的。 相似文献
999.
Scott Wushke Victor Spicer Xiang Li Zhang Brian Fristensky Oleg V. Krokhin David B. Levin Nazim Cicek Richard Sparling 《Systematic and applied microbiology》2017,40(5):245-253
Caldibacillus debilis GB1 is a facultative anaerobe isolated from a thermophilic aero-tolerant cellulolytic enrichment culture. There is a lack of representative proteomes of facultative anaerobic thermophilic Bacillaceae, exploring aerobic/anaerobic expression. The C. debilis GB1 genome was sequenced and annotated, and the proteome characterized under aerobic and anaerobic conditions while grown on cellobiose. The draft sequence of C. debilis GB1 contains a 3,340,752 bp chromosome and a 5,386 bp plasmid distributed over 49 contigs. Two-dimensional liquid chromatography mass spectrometry/mass spectrometry was used with Isobaric Tags for Relative and Absolute Quantification (iTRAQ) to compare protein expression profiles, focusing on energy production and conversion pathways. Under aerobic conditions, proteins in glycolysis and pyruvate fermentation pathways were down-regulated. Simultaneously, proteins within the tricarboxylic acid cycle, pyruvate dehydrogenase, the electron transport chain, and oxygen scavenging pathways showed increased amounts. Under anaerobic conditions, protein levels in fermentation pathways were consistent with the generated end-products: formate, acetate, ethanol, lactate, and CO2. Under aerobic conditions CO2 and acetate production was consistent with incomplete respiration. Through a direct comparison with gene expression profiles from Escherichia coli, we show that global regulation of core metabolism pathways is similar in thermophilic and mesophilic facultative anaerobes of the Phylum Proteobacteria and Firmicutes. 相似文献
1000.
Eliana F.A. Carvalho José A.S. Cavaleiro Moreno Meneghetti 《Inorganica chimica acta》2010,363(14):3945-3950
The synthesis and characterization of three new indium phthalocyanines bearing eight N-alkyl- or N-arylsulfonamide groups is described. The new compounds are {2,3,9,10,16,17,23,24-octakis[4-(4-methoxyphenylaminosulfonyl]phenoxy]phthalocyaninato}indium(III) chloride (7), {2,3,9,10,16,17,23,24-octakis[4-diethylaminosulfonyl)phenoxy]phthalocyaninato}indium(III) chloride (8) and {2,3,9,10,16,17,23,24-octakis[4-didodecylaminosulfonyl)phenoxy]phthalocyaninato}indium(III) chloride (9), and were obtained in 23-49% yields. The precursors of phthalocyanines 7-9 are sulfonamide-substituted phthalonitriles that can be prepared by reacting 4,5-bis(4-chlorosulfonylphenoxy)phthalonitrile (3) with amines. The nonlinear transmission (NLT) of complexes 7-9 was determined at 532 nm using ns pulses. All three phthalocyanines behave as reverse saturable absorbers with increasing efficiency of optical limiting in the order 7 < 8 < 9. A comparative analysis of the NLT results is attempted in terms of the structural differences in 7-9. 相似文献