15,831 research outputs found

    A Critical Analysis of the Effects of Colello v. SEC on International Securities Law Enforcement Agreements

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    The load carrying capacity of interbre joints are one of the key entities for build-up of strength inpaper materials. In order to gain insight in how to tailor the macroscopic properties of such materialsby chemical and/or mechanical treatments at a microscopic level, direct measurement of individualbre{bre crosses are typically performed. However, the state of loading in the interbre joint, intesting of individual bre{bre crosses, is in general very complex and an increased understandingfor how to evaluate the mechanical properties of interbre joints is desirable. In Paper A, amethod for manufacturing and measuring the strength of isolated interbre joints is presented. Themethod is applied to investigate the strength of bre{bre crosses at two dierent modes of loading.Also, an investigation on the manufacturing conditions is presented. The strength distribution ofindividually prepared bre{bre crosses is characterized and it was found that the median strengthin a peeling type of loading was about 20% compared to samples tested in the conventional shearingtype of loading. In Paper B, a procedure for evaluating interbre joint strength measurementsin terms of resultant forces and moments in the interbre joint region is presented. The methodis applied to investigate the state of loading in bre{bre crosses tested in peeling and shearing,respectively. It is shown that for a typical interbre joint strength test, the load components otherthan shear, cannot in general be neglected and is strongly dependent on the structural geometry ofthe bre{bre crosses. In Paper C, four distinctly dierent load cases; peeling, shearing, tearingand a biaxial type of loading was tested mechanically and evaluated numerically in order to gainmore information on how interbre joints behave in dierent modes of loading. In Paper D, thein uence of a chemical additive on the interbre joint strength is investigated on the microscopic(joint) scale and correlated to the eect previously observed on the macroscopic (sheet) scale. Xraymicrotomography and image analysis was used to understand structural changes in the brousnetwork in terms of the number of interbre joints as well as the average interbre joint contact area.The results showed that the median interbre joint strength increased by 18% upon adsorption, andthat the polyelectrolyte increased the number of contacts between the bres as well as an increasedarea of contact. In Paper E, the damage behaviour of individual interbre joints is analyzed. Froman extensive number of mechanical tests, the typical damage behaviour is identied and a failurecriterion is used to study the in uence of failure properties to give indications on how to tailor thematerial to optimize the joint strength.En av de viktigaste mekanismerna for den lastbarande formagan hos pappersmaterial ar brottegenskapernahos berfogarna. For att eektivt skraddarsy sadana materials egenskaper genom kemiskoch/eller mekanisk behandling samt for att forsta hur sadana modieringar paverkar egenskapernapa en mikroskopisk niva ar provning av individuella ber-ber-kors en allmant anvand metod. Belastningeni en berfog vid sadan provning ar dock generellt komplicerad och ytterligare kunskapom hur berfogars mekaniska egenskaper skall utvarderas ar onskvard. I Artikel A, presenterasen metod for tillverkning samt mekanisk provning av isolerade ber-kors vid tva olika typer avbelastning. Vidare undersoks hur torktrycket, torkmetoden samt graden av malning inverkar pafogstyrkan. Resultaten visar att brottlasten for en globalt akande belastning var omkring 20 % avbrottlasten for prov utforda med den konventionella skjuvande belastningen samt att styrkan hosindividuellt tillverkade berkors ar fordelade enligt en Weibull fordelning. I Artikel B, presenterasen numerisk metod for utvardering av fogstyrke-matningar med avseende pa kraft- och momentresultanternai gransytan mellan brerna. Metoden anvands for att studera belastningsmoden hosber-kors i tva principiellt olika lastfall. Resultaten visar att for ett typiskt berfogsprov, kan intelastkomponenterna, vid sidan av skjuvning, generellt forsummas da de ar starkt beroende avber-korsets geometri. I Artikel C, jamfors fogstyrkematningar under fyra principiellt olika lastfall; akande, skjuvande, rivande samt biaxiellt. De experimentella last-forskjutningskurvorna, samtde beraknade lastmoderna anvands for att undersoka vilket tillskott pa information de foreslagnalastfallen kan ge i hansyn till fogstyrkan hos massabrer. I Artikel D, undersoks en polymers (somabsorberats pa berytorna) inverkan pa saval berniva som pa natverksniva. Fiberfogstyrkan matsexperimentellt och eekten av den kemiska tillsatsen jamfors pa mikroskopisk niva (ber-kors) medtidigare uppmatt eekt pa makroskopisk niva (ark). Rontgentomogra och bildanalys anvands foratt undersoka de strukturella skillnaderna som uppstar i de brosa natverken vid absorption av enpolyamin och resultaten visar att antalet berfogar per berlangdenhet samt att medelkontaktareanokade. Resultaten visar ocksa att medianen av berfogsstyrkan okade med 18 %. Dessa eekter sammantagetar anledningen till varfor polyaminer, sasom PAH, ar sa eektiva for att oka torrstyrkanhos pappersmaterial. I Artikel E, karakteriseras skadebeteendet hos individuella berfogar franett omfattande antal matningar. Ett brottkriterium infors i den numeriska utvarderingsmetoden foratt studera skadebeteendet. Kanslighetsanalys och inverkan av brottparametrarna studeras ocksafor att ge indikationer pa hur egenskaperna kan skraddarsys for att optimera berfogstyrkan.QC 20140527BiMaC Innovatio

    LEUNIG regulates AGAMOUS expression in Arabidopsis flowers

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    LEUNIG was identified in a genetic screen designed to isolate second-site enhancer mutations of the floral homeotic mutant apetala2-1. leunig mutations not only enhance apetala2, but by themselves cause a similar but less-pronounced homeotic transformation than apetala2 mutations. leunig flowers have sepals that are transformed toward stamens and carpels, and petals that are either staminoid or absent. In situ hybridization experiments with leunig mutants revealed altered expression pattern of the floral homeotic genes APETALA1, APETALA3, PISTILLATA, and AGAMOUS. Double mutants of leunig and agamous exhibited a phenotype similar to agamous single mutants, indicating that agamous is epistatic to leunig. Our analysis suggests that a key role of LEUNIG is to negatively regulate AGAMOUS expression in the first two whorls of the Arabidopsis flower

    Mutations in the PERIANTHIA gene of Arabidopsis specifically alter floral organ number and initiation pattern

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    An open question in developmental biology is how groups of dividing cells can generate specific numbers of segments or organs. We describe the phenotypic effects of mutations in PERIANTHIA, a gene specifically required for floral organ patterning in Arabidopsis thaliana. Most wild-type Arabidopsis flowers have 4 sepals, 4 petals, 6 stamens, and 2 carpels. Flowers of perianthia mutant plants most commonly show a pentamerous pattern of 5 sepals, 5 petals 5 stamens, and 2 carpels. This pattern is characteristic of flowers in a number of plant families, but not in the family Brassicaceae, which includes Arabidopsis. Unlike previously described mutations affecting floral organ number, perianthia does not appear to affect apical or floral meristem sizes, nor is any other aspect of vegetative or floral development severely affected. Floral organs in perianthia arise in a regular, stereotypical pattern similar to that in distantly related species with pentamerous flowers. Genetic analysis shows that PERIANTHIA acts downstream of the floral meristem identity genes and independently of the floral meristem size and floral organ identity genes in establishing floral organ initiation patterns. Thus PERIANTHIA acts in a previously unidentified process required for organ patterning in Arabidopsis flowers

    The Arabidopsis homeotic genes APETALA3 and PISTILLATA are sufficient to provide the B class organ identity function

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    The class B organ identity genes, APETALA3 and PISTILLATA, are required to specify petal and stamen identity in the Arabidopsis flower. We show here that the activities of these two genes are sufficient to specify petals and stamens in flowers, in combination with the class A and C genes, respectively. Flowers of plants constitutively expressing both PISTILLATA and APETALA3 under the control of the 35S promoter from cauliflower mosaic virus consist of two outer whorls of petals and inner whorls of stamens. These plants also exhibit vegetative phenotypes that are not present in either of the singly (APETALA3 or PISTILLATA) overexpressing lines. These phenotypes include leaf curling and the partial conversion of later-arising cauline leaves to petals. The presence of additional floral whorls in flowers ectopically expressing APETALA3 and PISTILLATA and the rescue of missing organs in class A mutants by ectopic B function suggest that APETALA3 and PISTILLATA play an additional role in proliferation of the floral meristem

    Merits of Creating a Revised CTE National Research Agenda for 2020

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    This article promotes the idea that clearly focused scholarly inquiry needs direction developed through a collaborative and informative process. The authors propose that the National CTE Research Agenda adopted in 2008 should be revised and updated to reflect the contemporary issues and policies of the career and technical education profession. The aim of this discussion is to propose a systematic research approach with the potential to influence policy for career and technical education. The challenge for our profession will be to create a united and informed agenda that will transform policy, promote innovation in scholarly endeavors, and foster improved outcomes for all CTE stakeholders

    CLAVATA3 is a specific regulator of shoot and floral meristem development affecting the same processes as CLAVATA1

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    We have previously described the phenotype of Arabidopsis thaliana plants with mutations at the CLAVATA1 (CLV1) locus (Clark, S. E., Running, M. P. and Meyerowitz, E. M. (1993) Development 119, 397-418). Our investigations demonstrated that clv1 plants develop enlarged vegetative and inflorescence apical meristems, and enlarged and indeterminate floral meristems. Here, we present an analysis of mutations at a separate locus, CLAVATA3(CLV3), that disrupt meristem development in a manner similar to clv1mutations. clv3 plants develop enlarged apical meristems as early as the mature embryo stage. clv3 floral meristems are also enlarged compared with wild type, and maintain a proliferating meristem throughout flower development. clv3 root meristems are unaffected, indicating that CLV3 is a specific regulator of shoot and floral meristem development. We demonstrate that the strong clv3-2 mutant is largely epistatic to clv1 mutants, and that the semi-dominance of clv1 alleles is enhanced by double heterozygosity with clv3 alleles, suggesting that these genes work in the same pathway to control meristem development. We propose that CLV1 and CLV3 are required to promote the differentiation of cells at the shoot and floral meristem

    The importance of collegiality and reciprocal learning in the professional development of beginning teachers

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    This paper discusses factors which enhance induction experiences for beginning teachers. It reports the findings from case studies which explore the impact of new entrants to the teaching profession in Scotland. The data suggest that the most supportive induction processes mix both formal and informal elements, but that the informal elements such as collegiality, good communication and a welcoming workplace environment should not be underestimated. The study also highlights the potential benefits of a more collegiate environment for teachers across the career phases. Experienced teachers and new entrants had a range of experience to offer each other, thus creating more cohesive professional working which was supportive of early career teachers while encouraging reflection on practice among the more experienced professionals

    TSO1 functions in cell division during Arabidopsis flower development

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    We describe an Arabidopsis mutant, tso1, which develops callus-like tissues in place of floral organs. The tso1 floral meristem lacks properly organized three cell layers, and the nuclei of these cells are irregular in size and shape. Further analyses reveal partially formed cell walls and increased DNA ploidy in tso1 floral meristem cells, indicating defects in mitosis and cytokinesis. Our finding that TSO1 is required for organ formation in floral tissues but not in other tissues indicates that TSO1 may encode a floral-specific cell division component, or that TSO1 function is redundant in nonfloral tissues

    Abnormal flowers and pattern formation in floral

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    “From our acquaintance with this abnormal enabled to unveil the secrets that normal us, and to see distinctly what, from the regular we can only infer.” - J. W. von Goethe (1790
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