1,720,971 research outputs found
Potencial de almacenamiento y secuestro de carbono del huiro negro (Lessonia berteroana y L. spicata) en Áreas de Manejo y Explotación de Recursos Bentónicos (AMERB) del norte de Chile
Full text linkLas macroalgas pardas del orden Laminariales, llamadas también “kelps” o “huiros”, son responsables de gran parte del secuestro de dióxido de carbono en los ecosistemas costeros marinos, lo cual es clave en la adaptación y mitigación del cambio climático. También son un factor clave en el desarrollo de la economía azul. Para aprovechar el potencial del kelp, Chile planea implementar estrategias que permitan su desarrollo sustentable, como por ejemplo, medidas asociadas al carbono azul. El primer paso para ello es completar las brechas de información respecto a la capacidad de almacenamiento y secuestro de carbono de las especies marinas chilenas. En este trabajo, estudiamos dos especies alopátricas, Lessonia berteroana y L. spicata, que habitan en el intermareal y actualmente se comercializan como materia prima. Por un lado, para estimar el almacenamiento de carbono, se analizó la biomasa húmeda, la biomasa seca y el porcentaje de carbono contenido en muestras de los discos de adhesión y del tejido de las frondas de individuos en cuatro localidades del norte de Chile, junto con la densidad de las poblaciones. Por otro lado, para estimar el secuestro de carbono, se analizó la productividad primaria neta. Después, se realizó una revisión bibliográfica para crear un modelo que representara la dinámica del sistema de almacenamiento y secuestro de carbono, identificando los componentes existentes, las interacciones y la información faltante. Nuestros resultados indican que el carbono almacenado varía por especie, siendo mayor en L.spicata que en L. berteroana, varía entre estaciones y entre estructuras, pues las frondas capturan más carbono que el disco de adhesión. Esto último sugiere que las estimaciones más utilizadas de almacenamiento de carbono probablemente sobrestiman los porcentajes reales de almacenamiento en entornos naturales. Además, el secuestro de carbono a largo plazo dependerá de factores físicos y biológicos locales, tales como la temperatura, el viento, las corrientes, la topografía, la densidad de las poblaciones, entre otros. Futuros estudios deberían enfocarse en reducir la brecha de conocimiento en esta área, obteniendo datos más detallados que permitan realizar proyecciones más precisas del carbono almacenado en los tejidos y del que queda enterrado en los sedimentos o llega al océano profundo, generando modelos predictivos que permitan el análisis estratégico para la acción contra el cambio climático.Brown macroalgae of the order Laminariales, also known as kelp, are responsible for much of the carbon dioxide sequestration in coastal marine ecosystems, which is key to climate change adaptation and mitigation. It is also a key factor in the development of the blue economy. To harness the potential of kelps, the Chilean government plans to implement strategies that allow its sustainable development, such as blue carbon initiatives. The first step is to fill in information gaps regarding the carbon stock and sequestration capacity of the Chilean kelp species. In this work, we studied two allopatric species Lessonia berteroana and L. spicata, that inhabit the same ecological niche and are marketed unprocessed. On the one hand, to estimate carbon storage, the wet biomass, dry biomass and the percentage of carbon contained in samples of holdfasts, stipes and fronds tissue of individuals in four different localities were analyzed, together with the density of the populations. On the other hand, to estimate carbon sequestration, net primary productivity was analyzed. Subsequently, a bibliographic review was carried out to create a model that represents the dynamics of the carbon stock and sequestration system in each species, identifying the existing components, interactions, and missing information. Our results indicate that the carbon stored varies among species, being higher in L. spicata than in L. berteroana, varies among seasons and structures, as the stipes and fronds capture more carbon than the holdfast. This suggests that the most commonly used estimates of carbon storage may probably overestimate the actual carbon stock in natural settings. In addition, long-term carbon sequestration will depend on local physical and biological factors, such as temperature, wind, currents, topography and population density among other. Future studies should focus on reducing the knowledge gap in this area, obtaining more detailed data that allow more accurate projections of the carbon stored in tissues and the carbon buried in sediments or the one that reaches the deep ocean, generating predictive models that allow strategic analysis for action against climate change.FONDEF 20I10167 y Packard Grant 2021-73304Versión original del auto
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Phenology and ecophysiology of macroalgae Porphyra spp. (Bangiales, Rhodophyta) and Lessonia spp. (Laminariales, Phaeophyceae) in north-central Chile: latitudinal and seasonal variations.
No full textO propósito dos estudos fenológicos é descrever e compreender como o desenvolvimento dos organismos ocorre em resposta às variações ambientais que mudam ciclicamente e como certos fatores estimulam a geração de uma cascata de sinais e reações que abrangem desde mudanças moleculares, bioquímicas e fisiológicas, os que acabam se manifestando como padrões anuais de abundância e reprodução. As mudanças ambientais ocorrem em escalas temporais (diárias, sazonais, interanuais) e espaciais (latitudinal, em profundidade, em altitude) e têm um forte impacto no crescimento e desenvolvimento das espécies, em especial de aquelas com características sésseis. O objetivo deste estudo foi caracterizar os padrões fenológicos (sazonais e latitudinais) de abundância, reprodução, fotossíntese e capacidade antioxidante de dois gêneros de macroalgas de importância ecológica e econômica, Porphyra spp. (rodofícea) e Lessonia spp. (feofícea), distribuídas ao longo da costa norte e centro (25° - 34°S) do Chile. Os resultados mostram que variações sazonais de radiação e latitudinais de temperatura influenciam significativamente as respostas fenológicas e ecofisiológicas das espécies estudadas. No caso de Porphyra spp., o ajuste temporal mais notório envolve um desenvolvimento fenológico anual para a população do norte e perene para as do centro e sul. As características fisiológicas mostraram diminuição na eficiência fotossintetizante, pigmentos (clorofila α, carotenoides e ficobiliproteínas) e proteínas solúveis em primavera-verão, acompanhados por aumento da capacidade antioxidante. No caso de Lessonia e embora a abundância não tenha mostrado uma mudança sazonal nas populações, o ajuste temporal mais notório aconteceu nas características fisiológicas, com diminuição na eficiência fotossintetizante, pigmentos (clorofilas α e c, carotenoides), fenois e capacidade antioxidante durante o verão, acompanhado por aumento na absorptância do talo, ETRmax e NPQ. Estudos sobre as identidades taxonômicas das populações de Porphyra são necessários para distinguir entre possíveis padrões devido à caraterísticas da espécie de possíveis variações morfológicas ou ecotípicas. Estudos das espécies de Lessonia próximas aos seus limites de distribuição biogeográfica poderiam elucidar se as diferenças fenológicas e fisiológicas são devido a padrões dependentes das espécies ou são mascaradas por características ambientais locais. Os estudos fenológicos e as mudanças em nível bioquímico/fisiológico podem subsidiar novos destinos da biomassa produzida ou da matéria prima proveniente de organismos de importância econômica. Além disso, alterações nos padrões fenológicos e ecofisiológicos típicos podem direcionar a compreensão sobre os impactos de câmbios ambientais tais como os câmbios climáticos globais, contaminação e poluição, sobrexploração e as interações e dinâmica entre as populaçõesThe purpose of phenological studies is to describe and understand how the development of the organisms occurs in response to environmental variations which change cyclically and how certain factors stimulate the generation of signals and a cascade of reactions from molecular, biochemical and physiological levels, which at the end manifests annual patterns of abundance and reproduction. Environmental changes occur in time scale (daily, seasonal, interannual) and spatial scale (latitudinal, depth, altitude) and have a strong impact on growth and development of the species, especially those with sessile characteristics. The purpose of this study was to characterize the phenology (seasonal and latitudinal) of abundance, reproduction, photosynthesis and antioxidant capacity of two macroalgae with ecological and economic importance, Porphyra spp. (Rhodophyta) and Lessonia spp. (Phaeophyceae), distributed along the coast north and center (25° - 34°S) in Chile. The results show that seasonal changes in radiation and latitudinal temperature significantly influence the phenological and ecophysiological responses of the species studied. For Porphyra spp., the most notorious temporal adjustment involves an annual phenological development from north population in contrast to perennial populations from central and south. The physiological characteristics showed decrease in photosynthetic efficiency, pigments (chlorophyll a, carotenoids and phycobiliproteins) and soluble proteins in spring-summer, accompanied by increasing in antioxidant capacity. For Lessonia spp., although the abundance showed no seasonal changes between the populations, the most notoriously temporal adjustment occurs in physiological characteristics with decrease in photosynthetic efficiency, pigments (chlorophylls a and c, carotenoids), phenols and antioxidant capacity during the summer, followed by increase in thallus absorptance, ETRmax and NPQ. Studies on the taxonomic identity of Porphyra populations are required to distinguish between possible characteristics due to species-specific patterns from morphological or ecotypes variations. Studies in the species Lessonia near their limits of biogeographical distribution could elucidate whether the phenological and physiological differences are due to patterns species-specific or are masked by local environmental characteristics. The phenological studies and changes in the biochemical/physiological levels can subsidize new destination of biomass production and raw material from organisms economically important. Moreover, changes in typical phenological and ecophysiological patterns can give a light about environmental impacts of alterations such as global climate changes, contamination and pollution, overexploitation and interactions and dynamics between populations
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