3,751 research outputs found

    Assessing the potentially misleading nature of metrics and of those who assess and create them

    Get PDF
    This self-published note makes a formal critique of a paper published in Wiley’s Bioessays as an invited paper: Gutierrez, F.R.S., Beall, J., Forero, D.A. (2015) Spurious alternative impact factors: The scale of the problem from an academic perspective. Bioessays 37: 474-476. DOI: 10.1002/bies.201500011. I am of the opinion that several incorrect and even misleading statements have been made in that paper. The refusal by the authors to respond to these concerns publicly, as well as the excuse by the publisher to not consider this critique on the basis of “journal space limitations” further accentuates the concerns. This model of publishing also serves as a viable way of exposing ideas and criticisms that lie beyond the manipulated hand of the self-serving interests of publishers

    Generalized derivations and additive theory II

    Get PDF
    AbstractWe return to the theme of generalized derivations related to symmetric functions to correct the hypothesis of one of the main theorems of our first paper, so that all cases are now properly covered

    Increasing the Size of a Piece of Popcorn

    Full text link
    Popcorn is an extremely popular snack food in the world today. Thermodynamics can be used to analyze how popcorn is produced. By treating the popping mechanism of the corn as a thermodynamic expansion, a method of increasing the volume or size of a kernel of popcorn can be studied. By lowering the pressure surrounding the unpopped kernel, one can use a thermodynamic argument to show that the expanded volume of the kernel when it pops must increase. In this project, a variety of experiments are run to test the validity of this theory. The results show that there is a significant increase in the average kernel size when the pressure of the surroundings is reduced.Comment: Latex document, 14 pages, 4 figures, 1 page of table

    The temporal and spatial variation of arthropod associations inhabiting non-crop vegetation in a sisal crop, agave sisalana in the caatinga biome

    Get PDF
    Sisal, Agave sisalana Perrine, is cultivated for fiber production, with Brazil being its leading producer. Nowadays, given the increasing interest in organic products, the market for sisal could become an economical alternative for rural areas with low economic inputs. However, sisal is threatened by different pests and diseases. Conservation biological control could contribute to the limitation of these plant enemies, but this agroecosystem is poorly known. In this context, we aimed: (i) to identify the diversity of plants and arthropods and their potential relations, (ii) to study the spatial patterns of arthropods and plants in function of the proximity to the margin of the field, and (iii) to determine the minimum sampling effort needed to record the occurring biodiversity in a sisal crop. Arthropods were sampled using pit-fall traps located close to the border and in the inner plant of the sisal crop from June to September. Simultaneously, plant species and their abundance in quadrats next to each pitfall were recorded. Diversity indexes were calculated to describe the biodiversity, a redundancy analysis was performed to analyze relations among arthropods and plants and the spatial distribution was evaluated using the non-parametric Wilcoxon rank-sum test. The redundancy analysis and the Wilcoxon test revealed a temporal and spatial distribution of arthropods and plants during the period of study. Results indicated (i) similar temporal diversity patterns from June to July for both plants and arthropods, with a maximum in July, whereas in September the biodiversity increased for arthropods and decreased for plants; (ii) the importance of particular plant species for Collembola; and (iii) that arthropods seem to colonize the sisal crop from the fields beyond the crop during the rainy season. These results provide new information about arthropods and plant biodiversity from an agroecosystem in a semi-arid region and raise further queries about the management of sisal crops.This research was funded by Foundation for Science and Technology (FCT, Portugal) by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and CsF/CNPq (Programa Ciência Sem Fronteiras/CNPq).info:eu-repo/semantics/publishedVersio

    Assessing the potentially misleading nature of metrics and of those who assess and create them

    Get PDF
    This self-published note makes a formal critique of a paper published in Wiley’s Bioessays as an invited paper: Gutierrez, F.R.S., Beall, J., Forero, D.A. (2015) Spurious alternative impact factors: The scale of the problem from an academic perspective. Bioessays 37: 474-476. DOI: 10.1002/bies.201500011. I am of the opinion that several incorrect and even misleading statements have been made in that paper. The refusal by the authors to respond to these concerns publicly, as well as the excuse by the publisher to not consider this critique on the basis of “journal space limitations” further accentuates the concerns. This model of publishing also serves as a viable way of exposing ideas and criticisms that lie beyond the manipulated hand of the self-serving interests of publishers

    Croton argyrophyllus Kunth and Croton heliotropiifolius Kunth: phytochemical characterization and bioactive properties

    Get PDF
    Croton heliotropiifolius Kunth and Croton argyrophyllus Kunth are endemic plant species from northeastern Brazil widely used in folk medicine and scarcely studied. In this context, the essential oils (EO's) and methanolic extracts (leaves and stalk) of both species were chemically characterized, and their antioxidant and antimicrobial activities were assessed. The chemical characterization of the EO's identified sixty components,being the major ones in C. argyrophyllus bicyclogermacrene (14.0%), β-pinene (8.9%) and spathulenol (8.7%), and in C. heliotropiifolius limonene (16.9%), α-pinene (13.3%) and caryophyllene (12.1%). Essential oils and methanolic extracts from leaves of C. argyrophyllus possess greater antioxidant potential, which could be related to the high levels of total phenols and flavonols. The antimicrobial activity of C. argyrophyllus essential oil proven to be more efficient than chloramphenicol (30 μg mL−1), with a minimum inhibitory concentration (MIC) of 25 μL mL−1 against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and 10 μL mL−1 against B. cereus. Leaf extracts presented high activity against yeasts (MIC = 50 mg mL−1) being C. heliotropiifolius effective against Candida albicans and C. parapsilosis, while C. argyrophyllus was effective against C. glabrata. Overall results showed that these plant species are potential sources of phytochemicals with interest in the fields of both pharmacology (e.g., antimicrobial) and human health (e.g., antioxidant). Furthermore, in the socio-economic aspect, these results can improve and disseminate the cultivation of these species, inducing improvements in the rural populations.This work was financially supported by CNPQ/CsF and CAPES and UID/AGR/00690/2013 – CIMO funded by FEDER – Fundo Europeu de Desenvolvimento Regional through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT – Fundação para a Ciência e a Tecnologia, Portugal. The authors are also grateful to UFRB Herbarium for the help with the plant species identification.info:eu-repo/semantics/publishedVersio

    Binary Collisions and the Slingshot Effect

    Full text link
    We derive the equations for the gravity assist manoeuvre in the general 2D case without the constraints of circular planetary orbits or widely different masses as assumed by Broucke, and obtain the slingshot conditions and maximum energy gain for arbitrary mass ratios of two colliding rigid bodies. Using the geometric view developed in an earlier paper by the authors the possible trajectories are computed for both attractive or repulsive interactions yielding a further insight on the slingshot mechanics and its parametrization. The general slingshot manoeuvre for arbitrary masses is explained as a particular case of the possible outcomes of attractive or repulsive binary collisions, and the correlation between asymptotic information and orbital parameters is obtained in general.Comment: 12 pages, 7 figures, accepted for publication Dec'07, Celestial Mechanics and Dynamical Astronom

    Self-regulated Learning In Students Of Pedagogy

    Get PDF
    Self-regulated learning is the process by which students plan, monitor and regulate their own learning. The aim of this study was to investigate relationships between motivation to learn, implicit theories of intelligence and self-handicapping strategies, and to examine the association of these variables in the prediction of the use of learning strategies in students of Pedagogy. The sample consisted of 107 Pedagogy students of two private universities of a city of São Paulo state. Data were collected using four Likerttype scales. Multivariate linear regression analyses revealed that participants with higher scores in the Learning Strategies Scale also presented significantly higher scores in intrinsic motivation and fewer reports of use of self-handicapping strategies. Higher scores in metacognitive strategies were significantly associated with both intrinsic an extrinsic motivation and with fewer reports of use of selfhandicapping strategies. Results are discussed in terms of the contribution of Psychology to teacher education.2459323330Azevedo, A.S., Dias, P.C., Salgado, A., Guimarães, T., Lima, I., Barbosa, A., Teacher-student relationship and self-regulated learning in Portuguese compulsory education (2012) Paidéia (Ribeirão Preto), 22 (52), pp. 197-206Berger, J.-L., Karabenick, S.A., Motivation and students' use of learning strategies: Evidence of unidirectional effects in mathematics classrooms (2011) Learning and Instruction, 21 (3), pp. 416-428Blackwell, L.S., Trzesniewski, K.H., Dweck, C.S., Implicit theories of intelligence predict achievement across an adolescent transition: A longitudinal study and an intervention (2007) Child Development, 78 (1), pp. 246-263Bortoletto, D., Boruchovitch, E., Learning strategies and emotional regulation of pedagogy students (2013) Paidéia (Ribeirão Preto), 23 (55), pp. 235-242Boruchovitch, E., Conhecendo as crenças sobre inteligência, esforço e sorte de alunos brasileiros em tarefas escolares (2001) Psicologia: Refexão e Crítica, 14 (3), pp. 461-467Boruchovitch, E., Aprender a aprender: Propostas de intervenção em estratégias de aprendizagem (2007) Educação Temática Digital, 8 (2), pp. 156-167Boruchovitch, E., A motivação para aprender de estudantes em cursos de formação de professores (2008) Educação, 31 (1), pp. 30-38Boruchovitch, E., Escala de motivação para aprender de universitários (EMA-U): Propriedades psicométricas (2008) Avaliação Psicológica, 7 (2), pp. 127-134Boruchovitch, E., Ganda, D.R., (2009) Escala de Estratégias Autoprejudiciais, , Unpublished manuscript, Faculdade de Educação, Universidade Estadual de Campinas, São Paulo, BrazilBoruchovitch, E., Neves, E.R.C., (2005) Escala de Avaliação da Motivação Para Aprender de Estudantes Universitários, , Unpublished manuscript, Faculdade de Educação, Universidade Estadual de Campinas, São Paulo, BrazilBrophy, J.E., (2010) Motivating Students to Learn (3rd Ed.), , New York, NY: RoutledgeBzuneck, J.A., A motivação dos alunos em cursos superiores (2005) Questões Do Cotidiano Universitário, pp. 217-238. , M. C. R. A. Joly, A. A. A. Santos, & F. F. Sisto (Orgs.) São Paulo, SP: Casa do PsicólogoClayton, K., Blumberg, F., Auld, D.P., The relationship between motivation, learning strategies and choice of environment whether traditional or including an online component (2010) British Journal of Educational Technology, 41 (3), pp. 349-364Cunha, N.B., Boruchovitch, E., As estratégias de aprendizagem e a motivação para aprender na formação de professores (2012) Interamerican Journal of Psychology, 46 (2), pp. 247-253Dancey, C.P., Reidy, J., (2006) Estatística Sem Matemática Para Psicólogos: Usando SPSS Para Windows, pp. 178-218. , L. Viali, Trans., 3rd ed. Porto Alegre, RS: Artmed/BookmanDeci, E.L., Ryan, R.M., Self-determination theory: A macrotheory of human motivation, development, and health (2008) Canadian Psychology, 49 (3), pp. 182-185Deci, E.L., Ryan, R.M., Motivation, personality, and development within embedded social contexts: An overview of self-determination theory (2012) The Oxford Handbook of Human Motivation, pp. 85-107. , R. M. Ryan (Ed.) New York, NY: Oxford University PressDembo, M.H., (1994) Applying Educational Psychology, , New York, NY: LongmanDonaciano, B., Almeida, L.S., (2011) Estratégias de Estudo: Auscultando Os Estudantes Universitários de Moçambique Sobre As Suas Aprendizagens, , http://repositorium.sdum.uminho.pt/handle/1822/15863Dweck, C.S., (1999) Self-theories: Their Role in Motivation, Personality, and Development, , Philadelphia, PA: Psychology PressDweck, C.S., (2006) Mindset: The New Psychology of Success, , New York, NY: Random HouseGadbois, S.A., Sturgeon, R.D., Academic self-handicapping: Relationships with learning specifc and general self-perceptions and academic performance over time (2011) British Journal of Educational Psychology, 81, pp. 207-222Ganda, D.R., Boruchovitch, E., Self-handicapping strategies for learning of preservice teachers Estudos de Psicologia (Campinas), , no preloJones, E.E., Berglas, S., Control of attributions about the self through self-handicapping strategies: The appeal of alcohol and the role of underachievement (1978) Personality and Social Psychology Bulletin, 4 (2), pp. 200-206Karabenick, S.A., Dembo, M.H., Understanding and facilitating self-regulated help seeking (2011) New Directions for Teaching and Learning, 126, pp. 33-43King, R.B., How you think about your intelligence infuences how adjusted you are: Implicit theories and adjustment outcomes (2012) Personality and Individual Differences, 53 (5), pp. 705-709McCrea, S.M., Flamm, A., Dysfunctional anticipatory thoughts and the self-handicapping strategy (2012) European Journal of Social Psychology, 42 (1), pp. 72-81McCrea, S.M., Myers, A.L., Hirt, E.R., Self-handicapping as an anticipatory self-protection strategy (2009) Social Psychology: New Research, pp. 31-53. , E. P. Lamont (Ed.) Hauppauge, NY: Nova ScienceNisbet, J., Shucksmith, J., (1987) Estrategias de Aprendizaje, , Madrid, España: SantillanaPattal, E.A., Awad, G.H., Cestone, C.M., Academic potential beliefs and feelings: Conceptual development and relations with academics outcomes (2014) Self and Identity, 13 (1), pp. 58-80Pintrich, P.R., The role of goal orientation in self-regulated learning (2000) Handbook of Self-regulation, pp. 451-502. , M. Boekaerts, P. R. Pintrich, & M. Zeidner (Eds.) San Diego, CA: Elsevier Academic PressRattan, A., Savani, K., Naidu, N.V.R., Dweck, C.S., Can everyone become highly intelligent? Cultural differences in and societal consequences of beliefs about the universal potential for intelligence (2012) Journal of Personality and Social Psychology, 103 (5), pp. 787-803Reeve, J., Ryan, R.M., Deci, E.L., Jang, H., Understanding and promoting autonomous self-regulation: A self-determination theory perspective (2007) Motivation and Self-regulated Learning: Theory, Research, and Applications, pp. 223-244. , D. H. Schunk & B. J. Zimmerman (Eds.) Mahwah, NJ: Lawrence ErlbaumRhodewalt, F., Self-handicapping: On the self-perpetuating nature of defensive behavior (2008) Social and Personality Psychology Compass, 2 (3), pp. 1255-1268Ryan, R.M., Deci, E.L., Promoting self-determined school engagement (2009) Handbook of Motivation at School, pp. 171-195. , K. R. Wentzel & A. Wigfeld (Eds.) New York, NY: RoutledgeSantos, A.A.A., Boruchovitch, E., (2008) Escala de Avaliação de Estratégias de Aprendizagem, , Itatiba, SP: Universidade São Francisco. Manuscrito não publicadoSchunk, D.H., Zimmerman, B.J., (2012) Motivation and Self-regulated Learning: Theory, Research, and Applications, , New York, NY: RoutledgeVan Nuland, H.J.C., Taris, T.W., Boekaerts, M., Martens, R.L., Testing the hierarchical SDT model: The case of performance-oriented classrooms (2012) European Journal of Psychology of Education, 27 (4), pp. 467-482Weinstein, C.E., Acee, T.W., Jung, J., Self regulation and learning strategies (2011) New Directions for Teaching and Learning, 126, pp. 45-53Yeager, D.S., Miu, A.S., Powers, J., Dweck, C.S., Implicit theories of personality and attributions of hostile intent: A meta-analysis, an experiment, and a longitudinal intervention (2013) Child Development, 84 (5), pp. 1651-1667Zimmerman, B.J., A social cognitive view of self-regulated academic learning (1989) Journal of Educational Psychology, 81 (3), pp. 329-339Zimmerman, B.J., Investigating self-regulation and motivation: Historical background, methodological developments, and future prospects (2008) American Educational Research Journal, 45 (1), pp. 166-18

    Variabilidad espacial y temporal del vigor vegetativo en viñedo sin restricciones hídricas en la demanda evapotranspirativa

    Get PDF
    Aunque generalmente se asume que la respuesta de un cultivo a la dosis de riego seleccionada es homogénea en la totalidad del área cultivada, en la mayoría de los casos esto no se corresponde con la realidad. En este trabajo se presenta un estudio de la variabilidad espacial y temporal del vigor vegetativo en el cultivo del viñedo, mediante el uso de índices de vegetación (NDVI) y la elaboración de los correspondientes mapas estadísticos. El ensayo ha sido realizado en un viñedo experimental de cultivar Tempranillo (Vitis vinífera L.), donde se compararon cuatro bloques aleatorios con un tratamiento de riego al 100% de la demanda evapotranspirativa (ETc) del cultivo. Durante la fase de maduración, se realizaron semanalmente mapas de índices de vegetación mediante el uso de sensores multiespectrales cercanos, montados sobre vehículos terrestres. Se observó que la respuesta en el desarrollo vegetativo no mantuvo una homogeneidad espacio – temporal en las cuatro zonas de estudio, a pesar de haber recibido las mismas prácticas culturales. La utilización de este tipo de herramientas, sensores de vegetación y estadística inferencial, permite detectar zonas diferenciadas en el desarrollo vegetativo, pudiendo ser utilizado para la toma de decisiones sobre el manejo del cultivo, tales como el escalonamiento de la cosecha o la aplicación tanto de abonos como de fitosanitarios, en función del factor que produce dicho descenso de vegetación

    Micro-Terroir

    Get PDF
    El concepto de terroir en el vino está basado en la observación de que diferentes regiones, viñedos o secciones dentro del mismo viñedo, pueden producir vinos con identidades propias y muy diferentes entre sí. Este concepto se cristalizó con el fin de describir los aspectos únicos de un lugar particular (suelo, topografía y clima) que influyen y forman el vino que nace a partir de él. Para una misma posición geográfica, podemos pensar que factores tales como el suelo y la topografía son fijos, en el espacio y en el tiempo, sin embargo las plantas del cultivo de viñedo presentan microvariaciones locales con diversas respuestas adaptativas. En efecto, dentro de un mismo viñedo, aéreas aparentemente uniformes desde un punto de vista pedológico y topográfico presentan plantas con vigores vegetativos totalmente distintos, considerando todos los factores fijos. Estos micro – terroirs vegetativos proporcionan una diferenciación en la maduración de la uva, creando así una variación espacial y temporal en la calidad de la misma. Considerando los demás factores fijos y, partiendo del principio de que la variación espacial y temporal en el vigor vegetativo de una planta es un indicativo de su capacidad productiva, así como del potencial cualitativo del fruto, fueron controladas 80 hectáreas de viñedo mediante un sensor de vegetación. La base de datos, espacial y temporal, obtenida y posteriormente analizada por componentes principales, permitió elaborar zonas homogéneas de tratamiento que denominamos micro – terroirs. Como resultado, se encontró que existe una variabilidad espacial y temporal en las regiones aparentemente uniformes en términos pedológicos y topográficos, lo que sugiere una capacidad de adaptación genética que no siempre es fácil de tener en cuenta. La capacidad de monitorizar la variación espacial y temporal del vigor vegetativo de la vid, permitirá gestionar diferenciadamente las unidades geográficas distintas, desde el punto de vista de la calidad del vino
    corecore