58 resultados para F21
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Electro-oxidation of Mn2+ to MnO2 by cyclic voltammetry on gold in acidic (0.1 M H2SO4) and neutral (0.1 M Na2SO4) media was studied using electrochemical quartz-crystal microbalance (EQCM). The cyclic voltammetric behavior of Au is different in these electrolytes. From EQCM data of mass variation during cycling, the rate of electrodeposition of MnO2 is higher in the neutral medium than in the acidic medium. Specific capacitance of MnO2 deposited from the neutral medium is higher than that deposited from the acidic medium owing to different crystallographic structures.
Investigations Of Iron Adducts Of C-60 - Novel Fec60 In The Solid-State With Fe Inside The C-60 Cage
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By carrying out contact-arc vaporization of graphite in a partial atmosphere of Fe(CO)5, an iron-adduct with C60 has been obtained. The adduct has been characterized by various techniques including mass spectrometry, Fe-57 Mossbauer spectroscopy and Fe K-EXAFS. Properties of this adduct are compared with those of an adduct prepared by solution method where Fe is clearly outside the cage. Results suggest that FeC60 obtained from the gas phase reaction has the Fe atom in the cage.
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刺叶栎( Quercus ilex L.)是地中海的常绿树种,属于古老的第三纪植物区系成份。本文根据苏黎世——蒙特利尔学派的植被学基本原理,全面地研究了分布在整个威尼托(Veneto)大区的剌叶栎林,详细研究刺叶栎林的群落组成、结构及类型划分。同时,对威尼托的刺叶栎林同北京山区的栎林进行了比较研究。最后,着重研究了威尼托刺叶栎林的生物多样性。 威尼托的刺叶栎林主要分布在亚得里亚海沿岸(包括Foci del Tagtiamento和Bosco Nordio e Rosolina Mare两地)、Lago di Garda和Colli Euganei。 在气候上,亚得里亚海沿岸属于半地中海气候。加尔达湖区域(Laqo di Garda)则是接近欧洲中部的大陆性气候,且维持半地中海的气候特点。Co t l i Euganei是这两地气候的过渡类型,且更接近亚得里亚海沿岸的类型。 在亚得里亚海沿岸的刺叶栎林可以分为三类,第一类(I)是一些矮树丛,这是Fraxinus ornus和Quercus ilex混交林的前身,较干旱。第二类群落(II)缺少乔木层,灌木层是由一些盖度不大的刺叶栎代替,更干旱。第三类群落(Ⅲ)是一群在外貌上相同的成熟群落.Fraxinus ornus和Quercus ilex得到充分发展,较中生。 在加尔达湖区的刺叶栎林可划分为三类。第一类群落(I)代表一组耐旱、开敞的矮树丛,含有Sesterio Variae-Ostryelum群丛的特征种,这一类可划分为SesLerio Variae-Ostryetum群 丛,土壤贫脊和干旱。第二类群落(Ⅱ)代表一类较郁闭的矮树丛,含有较多的Prunetalia群落目的成份,土壤较贫脊。第三类群(Ⅲ)代表一类郁闭的群落,乔木具有很大的密度因而林下灌木不能充分发展。SesLerio Variae-Ostryetum群丛和Prunetalia群落目的成份均不多。 在Colli Euganei的刺叶栎林可划分为二类。第一类群落(I)是一些不郁闲的矮树林组成。大体上分为地中海旱生栎林和地中海假灌丛。第二类群落(II)代表了较中生状态的植被,刺叶标种群绝对郁闭。 北京地处华北大平原的西北部。北京山地的气候为温带陆地性季风气候,其地带性的落叶阔叶林是以栎林为典型。虽然这些栎林同意大利威尼托刺叶栎林是两种不同的森林类型,但两者之间是存在着一定的联系。其共有的科有20个,共有属有11个。他们在植物组成中,以禾本科,蔷薇科和豆科的植物种类为最多。在乔木层中,他们都是以壳斗科的栎属(Quercus)为优势,其中木犀科的白蜡属(Fraxinus)和槭树属(Acer)较多。 本文对威尼托大区刺叶栎林的物种多度分布格局进行了全面探讨,计算出刺叶栎林的几何分布模型、Broken-stick分布模型、Log分布模型、Log-normat分布模型等四种物种多度分布的理论模型,并将这些理论分布模型用“序列/多度”图解和“多度/频度”图解表示出来。其中,几何分布模型.Broken-stick1分布模型用“序列/多度”图解表示。Broken-stick2分布模型、Log分布模型、Log-normal分布模型用“多度/频度”图解表示。 对上述四个物种多度的理论分布同实际现察的物种多度分布进行X2分析,在5%的显著性水平上,对整个威托大区的刺叶 栎林,几何分布模型最能代表其物种多度分布,显著性最大;Log-normal分布模型也可以用来代表威尼托刺叶标妹的物种多度分布,其显著性次于几何分布模型的显著性。这表明威尼托的刺叶栎林尚处于演替的早期阶段,这些刺叶栎林曾受到严重破坏,现正在恢复。 通过比较Foci del Tagtiamento和Bosco Nordio加尔达湖区、Colli Euganei四个地方刺叶栎林的物种多度的几何分布模型和Log-normal分布模型,显示出Lago di Garda(加尔达湖区)的刺叶栎林生物多样性最好、Foci del Tagtiamento刺叶栎林生物多样性较好.Bosco Nordio的剌叶栎林生物多样性较差.Colli Euganei的刺叶栎林生物多样性最差。 再利用多样性指数计算全部威尼托大区剌叶栎林的生物多样性。计算的多样性指数有丰富度指数(包括Margalef指数、Men-hinick指数、Monk指数)、多样性指数(Shannon信息指数、Bri llouin个息指数、Gini指数、PIE指数、Mcintosh指数)、优势度指数(Berger-Parker指数、Simpson指数)、均一度指数(Pielou均一度指数、Brillouin均一度指数,PIE的V’均一度指数.PIE的V均一度指数,N2的V’均一度指数,N2的V均一度指数,Mclntosh均一度指数,Hill的F10均一度指数,Hill的E21均一度指数,Hill的F21的一度指数)。通过比较丰富度指数,多样性指数、均一度指数与优势度之间的关系,结果,Simpson优势度指数同Men-hinick物种丰富度指数、Shannon信息指数、Bril-louin信息指数、Pielou均一度指数,Brillouin均一度指数,Mcintosh均一度指数、PIE的V’均一度指数呈负相关关系,因此,上述生物多样性指数可以较好地反映威尼托大区刺叶栎林的生物多样性。反映出的结果是:加尔达湖区刺叶栎林生物多样性最好,Foci del Tagtiamento刺叶栎林生物多样性较好,Bosco Nordio的剌叶栎林生物多样性较差.Colli Euganei的刺叶栎林生物多样性最差。 生物多样性的研究显示出生物多样性同生境状况的密切联系。往往受人为干扰严重的群落生物多样性低、如Coli Euganei和亚得里亚海岸刺叶栋林;而受人为破坏较轻的群落其生物多样性高,如加尔达湖区刺叶栎。 生物多样性的研究还显示出生物多样性同群落演替的发展阶段密切相关,在群落演替初期,由于缺乏优势种,而又有大量物种侵入,物多样性相对较高。在群落演替中期,由于形成了一个或几个优势种,优势度的增加导致了生物多样性相对减低。如Foci del Tagtiamento刺叶栎林生物多样性高于Bosco Nordio刺叶栎林的生物多样性。到演替后期,随着更多物种的侵入,群落结构的复杂化、生物多样性又将逐步提高。
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This article analyzes the effects of globalization on implicit tax rates (ITRs) on labor income, capital income, and consumption in the EU15 and Central and Eastern European New Member States (CEE NMS). We find supportive evidence for an increase in the ITR on labor income in the EU15, but no effect on the ITR on capital income. There is evidence of convergence in terms of the ITR on consumption, as countries with higher than average ITR on consumption respond to globalization by decreasing their tax rates. There are important differences among the welfare regimes within the EU15. Social-democratic countries have decreased the tax burden on capital, but increased that on labor due to globalization. Globalization exerts a pressure to increase taxes on labor income in the conservative and liberal regimes as well. Taxes on consumption decrease in response to globalization in the conservative and social-democratic regimes. In the CEE NMS, there is no effect of globalization on the ITR on labor and capital income, but we find a negative impact on the ITR on consumption in the CEE NMS with higher than average ITR on consumption. (JEL H23, H24, H25, F19, F21)
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Cet article fait un recensement des analyses theoriques et empiriques concernant les effets possibles de la mobilite internationale des facteurs de production. les resultats et les recommendations du modele de base sont etablis quand prevalent le plein-emploi et l'ajustement complet des marches. les resultats des diverses analyses, dans un contexte de chomage structurel, sont ensuite identifies.
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The lacewings appear in many agroecosystems, preying several species of agricultural pests. They have great search capability, high voracity, high reproductive potential and are easily maintained in laboratory conditions. In laboratory rearing, to avoid problems in the mass production are recommended adjustments in the type and quality of prey to be used in order to obtain individuals with desirable characteristics. It is necessary special care with the laboratory populations, avoiding problems from inbreeding. Larvae were reared individually in Petri dishes (9.0 cm diameter) and fed with eggs of Sitotroga cerealella (Olivier, 1789) (Lepidoptera: Gelechiidae), in the amount of 25 mg / larva, while the adults were kept in PVC cylindrical cages (10 cm x 30 cm). Thus, the study analyzed the influence of the size of the population of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) on the pre-imaginal period (egg to adult) and reproductive capacity of this specie come from different populations and generations of laboratory. To this end, we used two populations, one of Jaboticabal (F-8 and F-21) and one of Piracicaba (F-6 and F-15), and subpopulations of 1, 5, 10, 15 and 20 couples, analyzing the incubation of eggs and the number of eggs per female in each population, generation and subpopulation. The pre-imaginal period (egg to adult) and the number of eggs per female of C. externa are influenced by the generation and the number of founding individuals, being these parameters favored when laboratory populations are established with the largest number of couples.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The silverleaf whitefly, Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae), is considered one of the most important pests of cowpea (Vigna unguiculata L. Walp.), limiting the productivity of this crop worldwide. Chemical control is still the main strategy for the management of populations of this insect. However, due to the harmful effects of pesticides on the environment and to humans, less injurious alternatives have been investigated. Along this line, the use of resistant genotypes can be a valuable tool for the control of the silverleaf whitefly. In this paper, we investigate some biological aspects of B. tabaci biotype B confined on 14 genotypes of cowpea. We evaluated the incubation period, egg viability, duration of nymphal stages, total duration of the juvenile phase, instar mortality and total mortality of the immature stage. The genotype MNC 99-541 F21 exhibited antibiosis against the whitefly, prolonging the lifecycle of the insect. The genotypes Canapu, BRS-Urubuquara and TE97-304 G-4 also exhibited antibiosis, causing high nymphal mortality. These results may help in breeding programmes to develop cowpea lines with resistance to B. tabaci biotype B.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Ubiquitylation plays an important role in the control of Na⁺ homeostasis by the kidney. It is well established that the epithelial Na⁺ channel ENaC is regulated by the ubiquitin-protein ligase NEDD4-2, limiting ENaC cell surface expression and activity. Ubiquitylation can be reversed by the action of deubiquitylating enzymes (DUBs). One such DUB, USP2-45, was identified previously as an aldosterone-induced protein in the kidney and is also a circadian output gene. In heterologous expression systems, USP2-45 binds to ENaC, deubiquitylates it, and enhances channel density and activity at the cell surface. Because the role of USP2-45 in renal Na⁺ transport had not been studied in vivo, we investigated here the effect of Usp2 gene inactivation in this process. We demonstrate first that USP2-45 protein has a rhythmic expression with a peak at ZT12. Usp2-KO mice did not show any differences from wild-type littermates with respect to the diurnal control of Na⁺ or K⁺ urinary excretion and plasma levels either on a standard diet or after acute and chronic changes to low- and high-Na⁺ diets, respectively. Moreover, they had similar aldosterone levels on either a low- or high-Na⁺ diet. Blood pressure measurements using telemetry did not reveal variations compared with control mice. Usp2-KO mice did not display alterations in expression of genes involved in sodium homeostasis or the ubiquitin system, as evidenced by transcriptome analysis in the kidney. Our data suggest that USP2 does not play a primary role in the control of Na⁺ balance or blood pressure.