147 research outputs found

    Increasing College Entrance Testing Vocabulary for Secondary Students with High-Incidence Disabilities

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    This study investigated the effects of an instructional technology device, specifically, a computer-based graphic organizer, called the Real-World Connections Vocabulary graphic organizer (Ellis, 2015), on vocabulary acquisition for college entrance testing skills of students with high-incidence disabilities. Although graphic organizers have been studied since the 1960’s, there is very little research regarding the effectiveness of computer-based graphic organizers when used with high school students with mild disabilities, and their benefit acquiring college entrance exam vocabulary knowledge, namely, the ACT exam. By means of a single-subject, multiple probe across participants design, this study demonstrated that a functional relation did exist between the tool and vocabulary acquisition for each of the three participants. Additionally, a social validity survey rendered positive results regarding its use

    Evolution of the telomere-associated protein POT1a in arabidopsis thaliana is characterized by positive selection to reinforce protein-protein interaction

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    © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Gene duplication is a major driving force in genome evolution. Here, we explore the nature and origin of the POT1 gene duplication in Arabidopsis thaliana. Protection of Telomeres (POT1) is a conserved multifunctional protein that modulates telomerase activity and its engagement with telomeres. Arabidopsis thaliana encodes two divergent POT1 paralogs termed AtPOT1a and AtPOT1b. AtPOT1a positively regulates telomerase activity, whereas AtPOT1b is proposed to negatively regulate telomerase and promote chromosome end protection. Phylogenetic analysis uncovered two independent POT1 duplication events in the plant kingdom, including one at the base of Brassicaceae. Tests for positive selection implemented in PAML revealed that the Brassicaceae POT1a lineage experienced positive selection postduplication and identified three amino acid residues with signatures of positive selection. A sensitive and quantitative genetic complementation assay was developed to assess POT1a function in A. thaliana. The assay showed that AtPOT1a is functionally distinct from single-copy POT1 genes in other plants. Moreover, for two of the sites with a strong signature of positive selection, substitutions that swap the amino acids in AtPOT1a for residues found in AtPOT1b dramatically compromised AtPOT1a function in vivo. In vitro-binding studies demonstrated that all three sites under positive selection specifically enhance the AtPOT1a interaction with CTC1, a core component of the highly conserved CST (CTC1/STN1/TEN1) telomere protein complex. Our results reveal a molecular mechanism for the role of these positively selected sites in AtPOT1a. The data also provide an important empirical example to refine theories of duplicate gene retention, as the outcome of positive selection here appears to be reinforcement of an ancestral function, rather than neofunctionalization. We propose that this outcome may not be unusual when the duplicated protein is a component of a multisubunit complex whose function is in part specified by other members

    Analysis of Poly(ADP-Ribose) Polymerases in Arabidopsis Telomere Biology

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    Maintaining the length of the telomere tract at chromosome ends is a complex process vital to normal cell division. Telomere length is controlled through the action of telomerase as well as a cadre of telomere-associated proteins that facilitate replication of the chromosome end and protect it from eliciting a DNA damage response. In vertebrates, multiple poly(ADP-ribose) polymerases (PARPs) have been implicated in the regulation of telomere length, telomerase activity and chromosome end protection. Here we investigate the role of PARPs in plant telomere biology. We analyzed Arabidopsis thaliana mutants null for PARP1 and PARP2 as well as plants treated with the PARP competitive inhibitor 3-AB. Plants deficient in PARP were hypersensitive to genotoxic stress, and expression of PARP1 and PARP2 mRNA was elevated in response to MMS or zeocin treatment or by the loss of telomerase. Additionally, PARP1 mRNA was induced in parp2 mutants, and conversely, PARP2 mRNA was induced in parp1 mutants. PARP3 mRNA, by contrast, was elevated in both parp1 and parp2 mutants, but not in seedlings treated with 3-AB or zeocin. PARP mutants and 3-AB treated plants displayed robust telomerase activity, no significant changes in telomere length, and no end-to-end chromosome fusions. Although there remains a possibility that PARPs play a role in Arabidopsis telomere biology, these findings argue that the contribution is a minor one

    The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae)

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    [Abstract] The linkage between 5S ribosomal DNA and other multigene families has been detected in many eukaryote lineages, but whether it provides any selective advantage remains unclear. In this work, we report the occurrence of linked units of 5S ribosomal DNA (5S rDNA) and U1 small nuclear DNA (U1 snDNA) in 10 razor shell species (Mollusca: Bivalvia: Pharidae) from four different genera. We obtained several clones containing partial or complete repeats of both multigene families in which both types of genes displayed the same orientation. We provide a comprehensive collection of razor shell 5S rDNA clones, both with linked and nonlinked organisation, and the first bivalve U1 snDNA sequences. We predicted the secondary structures and characterised the upstream and downstream conserved elements, including a region at −25 nucleotides from both 5S rDNA and U1 snDNA transcription start sites. The analysis of 5S rDNA showed that some nontranscribed spacers (NTSs) are more closely related to NTSs from other species (and genera) than to NTSs from the species they were retrieved from, suggesting birth-and-death evolution and ancestral polymorphism. Nucleotide conservation within the functional regions suggests the involvement of purifying selection, unequal crossing-overs and gene conversions. Taking into account this and other studies, we discuss the possible mechanisms by which both multigene families could have become linked in the Pharidae lineage. The reason why 5S rDNA is often found linked to other multigene families seems to be the result of stochastic processes within genomes in which its high copy number is determinan

    The Selaginella Genome Identifies Genetic Changes Associated with the Evolution of Vascular Plants

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    Vascular plants appeared ~410 million years ago then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes (1). We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first non-seed vascular plant genome reported. By comparing gene content in evolutionary diverse taxa, we found that the transition from a gametophyte- to sporophyte- dominated life cycle required far fewer new genes than the transition from a non-seed vascular to a flowering plant, while secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in post- transcriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the tasiRNA pathway and extensive RNA editing of organellar genes

    Methods used to evaluate the en dehors or turnout of dancers and classical ballet dancers: a literature review

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    A técnica do ballet clássico exige a realização máxima do en dehors ou turnout, caracterizado pela rotação externa de membros inferiores. Considerando a sua importância, diversos protocolos para a sua avaliação e mensuração têm sido propostos. O objetivo desta revisão foi investigar sistematicamente quais os métodos utilizados para avaliar o turnout de bailarinos clássicos e/ou praticantes de ballet clássico existentes atualmente. A busca foi feita nas bases de dados Scopus, Science Direct e PubMed, no mês de fevereiro de 2016, e os artigos encontrados deveriam: estar redigidos na língua inglesa, avaliar bailarinos clássicos ou dançarinos que praticassem ballet clássico e mensurar o en dehors ou turnout. Foram encontrados 593 artigos, dos quais 25 foram pré-selecionados para esta revisão, apresentando quinze diferentes métodos e instrumentos de mensuração do turnout: cinemetria; inclinômetro; turnout protactor ou transferidor para medir o turnout; goniômetro; Dupuis Tropometer; transferidor original; fotos dos sujeitos; discos rotacionais; teste de flexibilidade de Nicholas; flexímetro; desenho clínico dos pés; sujeito sobre um pedaço de papel ou solo ou quadro branco; ressonância magnética; filmagem do sujeito executando sequência de passos; Dasco Pro Angle Finder. Esta revisão apresenta forte evidência para afirmar que não há, até o presente momento, um método ou instrumento padrão-ouro para mensuração do turnout de bailarinos, de modo que esta costuma ser adaptada e escolhida de acordo com o objetivo de cada estudo.La técnica del ballet clásico exige la realización máxima del en dehors o turnout, caracterizado por la rotación externa de miembros inferiores. Considerando su importancia, varios protocolos para su evaluación y medición han sido propuestos. El objetivo de esta revisión ha sido investigar sistemáticamente los métodos utilizados para evaluar el turnout de bailarines clásicos y/o practicantes de ballet clásico existentes actualmente. Se hizo la búsqueda en las bases de datos Scopus, Science Direct y PubMed, en el mes de febrero de 2016, y los artículos encontrados deberían: estar redactados en la lengua inglesa, evaluar bailarines clásicos o bailarines que practicaran ballet clásico y medir el en dehors o turnout. Se encontraron 593 artículos, de los cuales se preseleccionaron 25 para esta revisión, presentándose 15 diferentes métodos e instrumentos de medición del turnout: cinemetría; inclinómetro; turnout protactor o transferidor para medir el turnout; goniómetro; Dupuis Tropometer; transferidor original; fotos de los sujetos; discos rotacionales; prueba de flexibilidad de Nicholas; flexímetro; diseño clínico de los pies; sujeto sobre un pedazo de papel o suelo o cuadro blanco; resonancia magnética; filmación del sujeto ejecutando secuencia de pasos; Daco Pro Angle Finder. Esta revisión presenta una fuerte evidencia para afirmar que no hay, hasta el momento, un método o instrumento estándar-oro para la medición del turnout de bailarines, de modo que ésta suele ser adaptada y elegida de acuerdo con el objetivo de cada estudio.The classical ballet technique requires the maximum en dehors or turnout, which is the lower limbs external rotation. Considering its importance, several evaluation and measurement protocols have been proposed. This review aims to investigate systematically which methods were used to assess the classical dancers’ or classical ballet practitioners’ turnout. A systematic search was made in the Scopus, Science Direct, and PubMed databases in February 2016 for studies written in English that evaluated classical dancers or ballerinas, and the en dehors or turnout was measured. We found 593 articles, of which 25 were pre-selected for this review, featuring fifteen different methods and instruments for measuring turnout: kinemetry; inclinometer; Turnout Protractor, or protractor to measure the turnout; goniometer; dupuis tropometer; original protractor; subjects photos; rotational discs; Nicholas flexibility test; fleximeter; clinical drawing of the feet; subject standing on a piece of paper, or soil, or whiteboard; magnetic resonance; filming the subject during a sequence of dance steps; Dasco pro angle finder. This review rovides convincing evidence that there is not a method or gold-standard instrument for measuring dancers’ turnout, therefore such measurement is usually adapted and chosen according to each study objectives
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