792 research outputs found
Comparative assessment of trial-level surrogacy measures for candidate time-to-event surrogate endpoints in clinical trials
No full textVarious meta-analytical approaches have been applied to evaluate putative surrogate endpoints (S) of primary clinical endpoints (T), however a systematic assessment of their performance is lacking. Existing methods in the meta-analytic framework can be grouped into two types conventional and model-based trial-level surrogacy (TLS) measures. Both conventional and model-based TLS measures assess the ability to predict the treatment effect on T based on an observed treatment effect on putative S. Conventional TLS measures include correlation coefficients and R-square measures from weighted linear regression. Model-based TLS includes Copula R(2) proposed by Burzykowski et al. (2001). We examined and compared the estimation performance of these frequently used surrogacy measures in a large-scale simulation study. The impact of several key factors on the estimation performance was assessed, including the strength of the true surrogacy, the amount of effective information provided by available data, and the range of within-trial treatment effect on S and T. The TLS can be estimated accurately and precisely by both types of surrogacy measures when the true surrogacy is strong, number of trials is large, and the range of within-trial treatment effects is wide. When one or more factors deviate from the "best" scenarios, both types of TLS measures tend to underestimate the true surrogacy with increased variability. The estimation performance of conventional measures is similar to model-based measures, but with higher computational efficiency. The findings are applied to a large individual patient data pooled analysis in colon cancer. (C) 2011 Elsevier B.V. All rights reserved
The developmental morphology of Leea guineensis. I. Vegetative development
No full textPT: J; CR: FUCHS C, 1963, STAIN TECHNOL, V38, P141 GERRATH JM, 1990, BOT GAZ, V151, P210 GOULD KS, 1986, CAN J BOT, V64, P1268 HALLE F, 1978, TROPICAL TREES FORES LACROIX CR, 1989, AM J BOT, V76, P1203 MEICENHEIMER RD, 1983, CAN J BOT, V61, P3430 MERRILL EK, 1986, CAN J BOT, V64, P2650 NAIR NC, 1968, J INDIAN BOT SOC, V47, P193 POSTEK MT, 1982, AM J BOT, V69, P556 RIDSDALE CE, 1974, BLUMEA, V22, P57 ROHWEDER O, 1983, SAMENPFLANZEN MORPHO RUTISHAUSER R, 1985, BOTANISCHE JB SYSTEM, V107, P415 SATTLER R, 1974, PHYTOMORPHOLOGY, V24, P22 SATTLER R, 1988, AM J BOT, V75, P1606 SATTLER R, 1988, ASPECTS FLORAL DEV, P1 SUGIYAMA M, 1988, AM J BOT, V75, P1598 TOMLINSON PB, 1982, AXIOMS PRINCIPLES PL, P162 TOMLINSON PB, 1987, ANNU REV ECOL SYST, V18, P1 WILD H, 1966, FLORA ZAMBESIACA 2, V2, P492; NR: 19; TC: 4; J9: BOT GAZ; PG: 6; GA: DU901Source type: Electronic(1
Status & solidarity through codeswitching: three plays by Dolores Prida
No full textThis analysis employs the sociolinguistic framework of status and solidarity (Holmes, 2001) to examine the use of codeswitching on the relational development between the characters in three plays by Cuban-American playwright Dolores Prida. The three plays discussed are Beautiful Se��oritas (1978), Coser y cantar (1981) and Bot��nica (1991). Linguistic scholars recognize the lack of linguistic analysis of literary texts; specifically, codeswitching at present is not fully explored as a linguistic phenomenon in written contexts. Furthermore, Prida's works have never before been appraised using linguistic methodology. Hence, this work aims to add to scholarly research in the fields of codeswitching, discourse analysis, and literary linguistics, using the status and solidarity framework to examine the codeswitching in Dolores Prida's plays. Dolores Prida is a feminist and Hispanic dramatist whose central theme is the search for identity of Hispanic immigrants, specifically women, in the United States today. Due to her ideological stance, it is expected that a strong emphasis on solidarity rather than status and the use of affective rather than referential speech functions are present in the relationships in her plays. Accordingly, the analysis of Bot��nica reveals that indeed codeswitching between the characters does affect their relational development in maintaining solidarity and intimacy. However, the relationships found in Beautiful Se��oritas and Coser y cantar do not offer such conclusions, due to the variable nature of the relationships identified. Further analysis of these and other literary works will more accurately determine benefits of the status and solidarity framework as applied to the codeswitching research
Bot and gender detection of twitter accounts using distortion and LSA notebook for PAN at CLEF 2019
No full textIn this work, we present our approach for the Author Profiling task of PAN 2019. The task is divided into two sub-problems, bot, and gender detection, for two different languages: English and Spanish. For each instance of the problem and each language, we address the problem differently. We use an ensemble architecture to solve the Bot Detection for accounts that write in English and a single SVM for those who write in Spanish. For the Gender detection we use a single SVM architecture for both the languages, but we pre-process the tweets in a different way. Our final models achieve accuracy over the 90% in the bot detection task, while for the gender detection, of 84.17% and 77.61% respectively for the English and Spanish languages
The developmental morphology of Leea guineensis. II. Floral development
No full textPT: J; CR: BENNEK C, 1958, BOT JB SYST, V77, P423 BUGNON F, 1953, PUBLICATION U DIJON, V11 CRONQUIST A, 1981, INTEGRATED SYSTEM CL CRONQUIST A, 1988, EVOLUTION CLASSIFICA DAHLGREN RMT, 1980, BOTANICAL J LINNEAN, V80, P91 ERDTMAN G, 1966, POLLEN MORPHOLOGY PL, V1 GAGNEPAIN MF, 1910, B SOC BOT FR, V57, P331 GERRATH JM, 1988, ASPECTS FLORAL DEV, P121 GERRATH JM, 1988, CAN J BOT, V66, P1334 GERRATH JM, 1988, CAN J BOT, V66, P209 GERRATH JM, 1988, THESIS U GUELPH GUEL GERRATH JM, 1989, CAN J BOT, V67, P1356 GERRATH JM, 1989, CAN J BOT, V67, P2371 GERRATH JM, 1989, CAN J BOT, V67, P803 HEYWOOD VH, 1978, FLOWERING PLANTS WOR LACROIX CR, 1990, BOT GAZ, V151, P204 LATIFF A, 1984, 4 U KEB COLL WORK PA, P33 MEDAN D, 1988, ASPECTS FLORAL DEV, P133 NAIR NC, 1957, WILD BOT NOT, V110, P160 NAIR NC, 1968, J INDIAN BOT SOC, V47, P193 POSLUSZNY U, 1980, CAN J BOT, V58, P2491 POSLUSZNY U, 1986, CAN J BOT, V64, P1620 RISDALE CE, 1974, BLUMEA, V22, P57 SATTLER R, 1973, ORGANOGENESIS FLOWER SMITH AC, 1985, FLORA VITIENSIS NOVA, V3, P712 SUSSENGUTH K, 1953, NATURLICHEN PFLANZ D, V20, P372 TARNAVSCHI IT, 1968, POLLEN SPORES, V10, P221 TOELKEN H, 1983, FLOWERING PLANTS AUS, P227 WILD H, 1966, FLORA ZAMBESIACA 2, V2, P492; NR: 29; TC: 6; J9: BOT GAZ; PG: 11; GA: DU901Source type: Electronic(1
Seasonal and spatial patterns of oxygen production, respiration and root-rhizome release in Potamogeton perfoliatus L. and Zostera marina L.
No full textOxygen release to the rhizosphere was measured in situ with O₂ microelectrodes and in hydroponic, split-compartment chambers. Light-dark experiments revealed that O₂ release from the rhizomes of Potamogeton perfoliatus L. was directly dependent on photosynthesis and that O₂ concentrations in sediments near the rhizomes started to decrease within 2 min after plants were darkened. Using Fick's first law of diffusion, the calculated net O₂ flux in P. perfoliatus was approximately 120 μmol g⁻¹ dry weight h⁻¹, similar to fluxes calculated from hydroponic measurements.
Root-rhizome O₂ release, photosynthesis and respiration were measured for P. perfoliatus and Zostera marina L., with split-compartment hydroponic chambers in spring, summer and fall. For Z. marina, variability of root-rhizome O₂ release, photosynthesis and respiration were observed between different sites within an eelgrass bed. The highest rates of O₂ release from roots and rhizomes occurred in spring for both species and declined during the summer. For P. perfoliatus, the shortest plants (< 10 cm stem length) had the highest O₂ release, about 43 μmol g⁻¹ dry weight h⁻¹. Root-rhizome O₂ release was significantly related to photosynthesis only for P. perfoliatus. Oxidation of the rhizosphere depended on root-rhizome O₂ release and biomass, which changed seasonally. Although weight-specific release rates were higher for P. perfoliatus than Z. marina, the potential oxidation of the rhizosphere was similar for both species (approximately 4–6 mmol O₂ m⁻² h⁻¹) because of relatively high Z. marina root and rhizome biomass.Journal Articl
CONSERVA BIO: APLICATIVO INFORMATIVO-DID?TICO SOBRE O JARDIM BOT?NICO DE JO?O PESSOA/PB
No full textO Conserva Bio ? um aplicativo informativo-did?tico desenvolvido para facilitar o acesso ?s
informa??es sobre a biodiversidade, ? fauna, ? flora e ? hist?ria do Jardim Bot?nico
Benjamim Maranh?o (JBBM), localizado em Jo?o Pessoa, Para?ba. Este projeto surgiu em
resposta ?s restri??es impostas pela pandemia de COVID-19, que limitou o acesso a
espa?os de educa??o ambiental e evidenciou a necessidade de recursos digitais que
promovam a educa??o ambiental. A proposta do Conserva Bio ? oferecer uma experi?ncia
de visita??o virtual imersiva, permitindo que usu?rios explorem o Jardim Bot?nico de
maneira aut?noma e interativa. O aplicativo integra conte?dos visuais e funcionais, como
textos, imagens e um game interativo, com o intuito de promover a continuidade da
aprendizagem e o engajamento com a natureza. Essa abordagem visa n?o apenas suprir a
car?ncia de ferramentas digitais, mas tamb?m sensibilizar o p?blico para a import?ncia da
preserva??o ecol?gica. Durante o processo de desenvolvimento, observou-se uma escassez
de aplicativos semelhantes no Brasil, especialmente voltados para jardins bot?nicos e que
integrem tecnologia interativa com a educa??o ambiental. Iniciativas como o Projeto Flora do
Brasil 2020 documentam a flora nacional, mas carecem da interatividade que o Conserva
Bio prop?e. Assim, o aplicativo se destaca ao integrar a hist?ria e a biodiversidade de um
espa?o local espec?fico, proporcionando uma experi?ncia educativa ?nica e contextualizada.
O desenvolvimento do Conserva Bio se baseou em observa??es feitas pelo pesquisador
durante est?gio no JBBM, que revelaram a necessidade de promover a biodiversidade do
local ? sociedade e ao ambiente educacional. Para abordar essa quest?o, uma pesquisa
bibliogr?fica inicial identificou a aus?ncia de aplicativos dedicados ?s Unidades de
Conserva??o no Brasil. Ap?s essa constata??o, o projeto foi submetido ? chamada
Interconecta chamada Interconecta de n?mero 02/2021 do IFPB - Campus Cabedelo e
aprovado com bolsa, al?m de ter recebido a autoriza??o do Conselho de ?tica em Pesquisa.
O procedimento metodol?gico incluiu a coleta de dados por meio de um question?rio com
funcion?rios do JBBM. Apesar de ter uma amostra reduzida, as respostas indicaram uma
significativa car?ncia de recursos digitais. A equipe enfatizou a import?ncia de um aplicativo
que n?o apenas reunisse informa??es, mas que tamb?m engajasse o p?blico por meio de
interatividade. O Conserva Bio tamb?m pode servir como um recurso pedag?gico valioso,
integrando-se a curr?culos escolares e atividades extracurriculares. Por meio de suas
funcionalidades, o aplicativo permite que professores utilizem conte?dos digitais de forma
inovadora, estimulando o aprendizado ativo e o desenvolvimento do pensamento cr?tico em
alunos de diversas idades. Embora a vers?o beta do aplicativo tenha sido um avan?o, o
atraso na implementa??o da vers?o final destacou a necessidade de ajustes que ainda
precisam ser feitos. As contribui??es do Conserva Bio s?o te?ricas, ao enriquecer a
discuss?o sobre o uso de tecnologias digitais na educa??o ambiental, e pr?ticas, ao servir
como uma ferramenta de aprendizado acess?vel a diversos p?blicos. Para estudos futuros,
recomenda-se uma avalia??o cont?nua do aplicativo ap?s sua implementa??o, incluindo
novas funcionalidades, como a finaliza??o do jogo e atualiza??es de conte?do. O Conserva
Bio representa um passo importante na integra??o da tecnologia com a educa??o ambiental,
demonstrando que ? poss?vel avan?ar na divulga??o e valoriza??o da biodiversidade
Exploring Cognitive Bias Triggers in COVID-19 Misinformation Tweets: A Bot vs. Human Perspective
No full textDuring the COVID-19 pandemic, the proliferation of misinformation on social
media has been rapidly increasing. Automated Bot authors are believed to be
significant contributors of this surge. It is hypothesized that Bot authors
deliberately craft online misinformation aimed at triggering and exploiting
human cognitive biases, thereby enhancing tweet engagement and persuasive
influence. This study investigates this hypothesis by studying triggers of
biases embedded in Bot-authored misinformation and comparing them with their
counterparts, Human-authored misinformation. We complied a Misinfo Dataset that
contains COVID-19 vaccine-related misinformation tweets annotated by author
identities, Bots vs Humans, from Twitter during the vaccination period from
July 2020 to July 2021. We developed an algorithm to computationally automate
the extraction of triggers for eight cognitive biase. Our analysis revealed
that the Availability Bias, Cognitive Dissonance, and Confirmation Bias were
most commonly present in misinformation, with Bot-authored tweets exhibiting a
greater prevalence, with distinct patterns in utilizing bias triggers between
Humans and Bots. We further linked these bias triggers with engagement metrics,
inferring their potential influence on tweet engagement and persuasiveness.
Overall, our findings indicate that bias-triggering tactics have been more
influential on Bot-authored tweets than Human-authored tweets. While certain
bias triggers boosted engagement for Bot-authored tweets, some other bias
triggers unexpectedly decreased it. Conversely, triggers of most biases
appeared to be unrelated to the engagement of Human-authored tweets. Our work
sheds light on the differential utilization and effect of persuasion strategies
between Bot-authored and Human-authored misinformation from the lens of human
biases, offering insights for the development of effective counter-measures
Lobe-generating centres in the simple leaves of Myriophyllum aquaticum: evidence for KN1-like activity
No full textBackground and Aims
The mature morphology of most plants can usually be said to consist of three mutually exclusive organs: leaves, stems, and roots. The vast majority of mature morphologies may be easily grouped into one of these mutually exclusive categories. However, during very early stages of development and in many instances from inception, the division between organ categories becomes fuzzy due to the overlap in developmental processes that are shared between the aforementioned mutually exclusive categories. One such overlap has been described at the gene level where KNOXI homologues, transcription factors responsible for maintaining indeterminate cell fate, are expressed in the shoot apical meristem and during early stages of compound leaf development. This study characterizes the occurrence and spatial localization of mRNA of a KNOXI homologue, MaKN1, during the early stages of development in the simple leaves of Myriophyllum aquaticum, an aquatic angiosperm from the family Haloragaceae exhibiting pentamerous whorls of finely lobed leaves.
Methods
A 300-bp KNOXI fragment was sequenced from M. aquaticum and used in an RNA localization study to determine the temporal and spatial expression of KNOXI during the early stages of leaf lobe development in M. aquaticum. The developmental sequence of leaves of M. aquaticum was also described using scanning electron microscopy.
Key Results
Lobe development of M. aquaticum occurs in two very distinct regions at the leaf base in an alternating fashion reminiscent of a distichous shoot system. It was discovered that MaKN1 expression is localized to both the shoot apical meristem and early stages of leaf primordia development (P1–P7). Initially, MaKN1 is expressed ubiquitously throughout primordia (P1–P3); however, as lobes develop, MaKN1 becomes localized to recently emerged lobe primordia, and disappears as lobes develop basipetally.
Conclusions
The pattern of gene expression is indicative of shared developmental processes during early development between shoots, compound leaves, highly lobed simple leaves and unifoliate simple leaves which lack KNOXI expression. These findings are supportive of Arber's less rigid ‘partial shoot’ theory, which conceptualizes compound leaves as having shoot-like elements
A temperature state estimator for a load sensing hub bearing unit
No full textDelft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
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