1,720,956 research outputs found
La salud del suelo en la horticultura periurbana del Área Metropolitana de Buenos Aires: diagnóstico en producciones hortícolas familiares y experimentación a campo
Full text link[Resumen]
Los sistemas hortícolas, altamente intensificados y dependientes de insumos externos, enfrentan desafíos
ambientales y de inocuidad alimentaria debido a un manejo inadecuado. En el cinturón verde bonaerense,
se han reportado signos de degradación en suelos hortícolas, lo que ha llevado a algunos productores a
adoptar enfoques agroecológicos. Sin embargo, son escasos los estudios sobre el impacto del manejo
hortícola en la salud del suelo. Por lo tanto, este trabajo tuvo como objetivo evaluar el efecto de la
horticultura periurbana continua en el Área Metropolitana de Buenos Aires, mediante a) el diagnóstico de
la calidad del suelo en producciones hortícolas familiares y b) la realización de experimentos a campo, con
el fin de promover prácticas agropecuarias que reduzcan el impacto ambiental en la producción de
alimentos. Se analizó el nivel de transición agroecológica y la salud del suelo en establecimientos hortícolas,
agroecológicos y convencionales, de Florencio Varela. Luego, se realizó un ensayo a campo durante tres
años, considerando diferentes tipos de fertilización (sin fertilización, cama de pollo y fertilizante químico)
y cultivos (hortícolas y florícolas), seguido de barbecho natural. El nivel de transición se evaluó con la
Herramienta para la Evaluación del Desempeño de la Agroecología. Para estudiar la salud del suelo se
determinó: densidad aparente (Dap), humedad gravimétrica (H), estabilidad de agregados (EE), pH,
conductividad eléctrica (CE), carbono orgánico total (COT), nitrógeno total (NT), fósforo extractable (PE),
respiración basal (RB) y respiración inducida por sustrato (RIS) de 0-10 cm de profundidad. Los resultados
indicaron que, aunque el nivel de transición agroecológica fue bajo (39 y 52 %), los establecimientos
agroecológicos presentaron puntuaciones más altas, especialmente en gestión e innovación. Asimismo, si
bien el uso hortícola afectó la calidad del suelo (redujo COT y EE, elevó pH y PE), los enfoques
agroecológicos mejoraron EE, COT y RB respecto a los convencionales. En el ensayo a campo, pH y CE
aumentaron después del ciclo horti-florícola, y el barbecho natural redujo CE sin restaurar los valores
iniciales del pH. EE y COT se incrementaron con el agregado de cama de pollo durante el ciclo hortiflorícola,
luego del barbecho natural se mantuvo superior con esta misma fertilización. En contraste, testigo
y fertilizante químico mostraron reducción de COT con el ciclo horti-florícola y, el barbecho natural
permitió que solo las parcelas con fertilizante químico recuperaran valores iniciales. Respecto a PE, agregar
cama de pollo y fertilizante químico lo aumentaron durante el ciclo horti-florícola, superando los valores
iniciales, mientras que en testigo no se observaron cambios. El laboreo intenso durante el ciclo hortiflorícola
redujo pH, COT y PE, independientemente de la fertilización y la inclusión de habas mejoró EE y
RIS. Aún hay potencial por explotar y limitaciones por superar para mejorar la calidad de los suelos
destinados a la producción de alimentos frescos. La aplicación de prácticas vegetativas y enmiendas
adecuadas y la evaluación de indicadores del suelo más sensibles permiten recuperar y mantener su salud.
Pero, es necesario fomentar el trabajo participativo con los productores para implementar prácticas de
manejo efectivas y adaptadas a las condiciones locales.[Resumo]
Os sistemas hortícolas, altamente intensificados e dependentes de insumos externos, enfrontan desafíos
ambientais e de inocuidade alimentaria debido a un manejo inadecuado. En el cinturón verde bonaerense,
se han reportado signos de degradación en suelos hortícolas, lo que ha llevado a algunos productores a
adoptar enfoques agroecológicos. Sen embargo, son escasos os estudios sobre o impacto do manejo hortícola
na saúde do suelo. Polo tanto, este traballo tivo como obxectivo avaliar o efecto da horticultura periurbana
continua na Área Metropolitana de Bos Aires, mediante a) o diagnóstico da calidade do chan nas producións
hortícolas familiares e b) a realización de experimentos no campo, co fin de promover prácticas
agropecuarias que reduzcan o impacto ambiental na produción de alimentos. Se analizou o nivel de
transición agroecolóxica e a saúde do suelo en establecementos hortícolas, agroecolóxicos e convencionais,
de Florencio Varela. Despois, realizou un ensayo a campo durante tres anos, considerando diferentes tipos
de fertilización (sen fertilización, cama de pollo e fertilizante químico) e cultivos (hortícolas e florícolas),
seguido de barbecho natural. El nivel de transición se evaluó con la Herramienta para la Evaluación del
Desempeño de la Agroecología. Para estudiar la salud del suelo se determinó: densidad aparente (Dap),
humedad gravimétrica (H), estabilidad de agregados (EE), pH, conductividad eléctrica (CE), carbono
orgánico total (COT), nitrógeno total (NT), fósforo extractable (PE), respiración basal (RB) e respiración
inducida por substrato (RIS) de 0-10 cm de profundidade. Os resultados indicaron que, aínda que o nivel de
transición agroecolóxica foi baixo (39 e 52 %), os establecementos agroecolóxicos presentaron puntuacións
máis altas, especialmente en xestión e innovación. Asimismo, si ben o uso hortícola afectou a calidade do
chan (rexunto COT e EE, elevou pH e PE), os enfoques agroecolóxicos melloraron EE, COT e RB respecto
aos convencionais. No ensayo a campo, pH e CE aumentaron despois do ciclo horti-florícola, e o barbecho
natural redujo CE sen restaurar os valores iniciais do pH. EE y COT se incrementaron con el agregado de
cama de pollo durante el ciclo horti-florícola, luego del barbecho natural se mantuvo superior con esta
misma fertilización. En contraste, testigo e fertilizante químico mostraron redución de COT co ciclo hortiflorícola
e, o barbecho natural permitiu que só as parcelas con fertilizante químico recuperaran valores
iniciais. Respecto a PE, agregar cama de pollo e fertilizante químico o aumentaron durante o ciclo hortiflorícola,
superando os valores iniciais, mentres que en testemuño non se observaron cambios. O traballo
intenso durante o ciclo horti-florícola redujo pH, COT e PE, independentemente da fertilización e da
inclusión de habas mellorou EE e RIS. Aún hai potencial por explotar e limitacións por superar para mellorar
a calidade dos chans destinados á produción de alimentos frescos. A aplicación de prácticas vexetativas e
enmiendas adecuadas e a avaliación dos indicadores do chan máis sensibles permiten recuperar e manter a
súa saúde. Pero, é necesario fomentar o traballo participativo cos produtores para implementar prácticas de
manejo efectivos e adaptadas ás condicións locais.[Abstract]
Horticultural systems, highly intensified and dependent on external inputs, face environmental and food
safety challenges due to inadequate management. In the Buenos Aires green belt, signs of degradation have
been reported in horticultural soils, leading some farmers to adopt agroecological approaches. However,
studies on the impact of horticultural management on soil health are scarce. Therefore, this work aimed to
evaluate the effect of continuous peri-urban horticulture in the Metropolitan Area of Buenos Aires, by a)
diagnosing soil quality in family horticultural productions and b) conducting field experiments, to promote
agricultural practices that reduce the environmental impact on food production. The level of agroecological
transition and soil health in agroecological and conventional horticultural establishments in Florencio Varela
were analysed. Then, a field trial was conducted for three years, considering different types of fertilisations
(control with no fertilisation, poultry litter and chemical fertiliser) and crops (horticultural and floricultural),
followed by natural fallow. The transition level was evaluated with the Tool for Agroecology Performance
Evaluation. To study soil health, the following were determined: bulk density (BD), gravimetric moisture
(H), aggregate stability (AS), pH, electrical conductivity (EC), total organic carbon (TOC), total nitrogen
(TN), extractable phosphorus (EP), basal respiration (BR) and substrate-induced respiration (SIR) from 0-
10 cm depth. The results indicated that although the agroecological transition score was low (39 and 52%),
self-defined agroecological farms had higher scores, especially in management and innovation. Also,
although horticultural use affected soil quality (reduced TOC and AS, increased pH and EP), agroecological
approaches improved AS, TOC and RB with respect to conventional ones. In the field trial, pH and EC
increased after the horticultural-floricultural cycle, and natural fallow reduced EC without restoring initial
pH values. AS and TOC increased with the addition of poultry litter during the horticultural cycle; after the
natural fallow, it remained higher with this same fertilisation. In contrast, the control and chemical fertiliser
showed a reduction in TOC with the horticultural-floricultural cycle, and the natural fallow allowed only
the plots with chemical fertiliser to recover initial values. Regarding EP, adding poultry litter or chemical
fertiliser increased it during the horticultural-floricultural cycle, surpassing the initial values, while no
changes were observed in the control. Intense tillage during the horticultural cycle reduced pH, TOC and
EP, independently of fertilisation, and the inclusion of fava beans improved AS and RIS. There is still
potential to be exploited and limitations to be overcome to improve the quality of soils for fresh food
production. The application of appropriate vegetative practices and amendments, and the evaluation of
sensitive soil indicators, make it possible to recover and maintain soil health. However, it is necessary to
encourage participatory work with producers to implement effective management practices adapted to local
conditions
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
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
- …
