1,720,953 research outputs found
Factores fisicoquímicos que influyen en la producción de bioplásticos tipo PHA en el género Bacillus spp
No full textLos plásticos de origen petroquímico son usados deliberadamente y su demanda ha
aumentado, lo que ha generado más residuos que afectan el medio ambiente debido a la
demora en su degradación y emisión de toxinas. Estos residuos llegan a corrientes
hídricas y causan daños en los animales.
Por eso, se han estudiado los PHA; plásticos biodegradables producidos por bacterias y
hongos gracias a su metabolismo y genética. Uno de los microorganismos con esta
capacidad es Bacillus spp. Estos biopolímeros son biodegradables y producen
moléculas benéficas para el suelo, pero no son viables para la industria debido a sus
altos costos de producción por requerir fuentes de carbono ricas en carbohidratos.
Se realizó una revisión sobre la producción de plásticos biodegradables a partir de
diferentes fuentes de carbono por medio del Bacillus spp. Donde se describe el proceso
metabólico y genético que realiza este microorganismo. Asimismo, la implementación
de diferentes fuentes de carbohidratos alternativas como lo son residuos de la industria
agrícola y alimentaria, para poder proporcionar alternativas sostenibles y que reduzcan
costos a la industria de los plásticos. Tras la revisión bibliográfica de 53 artículos de
diferentes bases de datos reconocidas, se concluye que el género Bacillus spp, tiene
gran potencial variando las condiciones fisicoquímicas como la temperatura, pH,
relación carbono nitrógeno y fuente de carbono fermentable con el que se desarrolle. Se
ha registrado el uso de residuos industriales tales como aceite de canola y residuos de
uva, como carbohidrato fermentable.Plastics of petrochemical origin are used deliberately and their demand has increased,
which has generated more waste that affects the environment due to the delay in its
degradation and the emission of toxins. These residues reach water currents and cause
damage to animals.
For this reason, PHAs have been studied; biodegradable plastics produced by bacteria
and fungi thanks to their metabolism and genetics. One of the microorganisms with this
ability is Bacillus spp. These biopolymers are biodegradable and produce beneficial
molecules for the soil, but they are not viable for the industry due to their high
production costs as they require carbon sources rich in carbohydrates.
A review was carried out on the production of biodegradable plastics from different
carbon sources by means of Bacillus spp. Where the metabolic and genetic process
carried out by this microorganism is described. Likewise, the implementation of
different sources of alternative carbohydrates such as residues from the agricultural and
food industry, in order to provide sustainable alternatives that reduce costs to the
plastics industry. After the bibliographic review of 53 articles from different recognized
databases, it is concluded that the genus Bacillus spp has great potential by varying the
physicochemical conditions such as temperature, pH, carbon nitrogen ratio and
fermentable carbon source with which it develops. Industrial residues such as canola oil
and grape residues have been reported for use as a fermentable carbohydrate.Tabla de contenido
1. Resumen 6
2. Abstract 7
3. Introducción 8
4. Objetivo 9
4.1 Objetivo general 9
4.2 Objetivos específicos 9
3. Antecedentes 10
4. Marco teórico 14
4. 1 Plásticos convencionales 14
4.1.1 Historia 14
4.1.2 Clasificación del plástico 18 15
4.1.2.1 Origen 17 15
4.1.2.2 Estructura molecular17 15
4.1.2.3 Respuesta termo-mecánica18 16
4.1.3 Marco Legal 16
4. 2 Biopolímeros 17
4.2.1 Clasificación de los biopolímeros 18
4.2.2 Polihidroxialcanoatos (PHA) 19
4.2.2.1 Clasificación de PHA 20
4.2.2.2 Rutas de biosintesis 21
4.2.2.3.2 Características genéticas de Bacillus cereus 25
4.2.2.4 Tecnicas de deteccion cuntificación y caracterización del PHA 26
4.2.2.5 Fermentación para producir PHA 26
4.2.2.5.1 Fuentes de carbono alternativas 27
4.2.2.6 Extraccion del PHA 27
4.2.2.7 Biodegradación del PHA 28
4.2.2.8 Aplicaciones del PHA 28
5. Diseño metodológico 30
5. 1 Tipo de estudio 30
5.2 Universo 30
7.097 artículos científicos o trabajos de grado en idioma inglés y español de la
base de datos Nature, Oxford academic, Sage journals, Scopus, Taylor and
Francis Group y Google Scholar relacionados con polihidroxialcanoatos (PHA)
y género Bacillus 30
5.3 Población 30
5.4 Muestra: 30
5.5 Criterios de inclusión: 30
5.6 Criterio de exclusión: 30
5.7 Herramienta estadística: 31
6. Resultados 33
6.1 Condiciones fisicoquímicas 44
6.2 Rutas metabólicas y enzimas empleadas en por Bacillus spp. 46
4
6.3 Fuentes de carbono alternativas. 48
6.4 Extracción y tratamiento de PHA 48
6.5 Limitaciones y beneficios de la producción de PHA 49
7. Discusión 52
8. Conclusiones 54
9. Referencias bibliográficas 55PregradoBacteriólogo(a) y Laboratorista Clínic
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
