1,720,955 research outputs found
Respuestas Ecofisiológicas Desarrolladas por Peumus boldus Mol. Frente a Condiciones de Restricción Hídrica
No full textRespuestas Ecofisiológicas Desarrolladas por Peumus boldus Mol. Frente a Condiciones de Restricción Hídrica
Get PDFMemoria para optar al Título
Profesional de Ingeniero ForestalPeumus boldus (Boldo), es una especie arbórea endémica de Chile, que comúnmente se
desarrolla en un clima mediterráneo, en este, debe enfrentar períodos estivales
desfavorables, principalmente por la elevada radiación, altas temperaturas y la restricción
hídrica de la estación. En estas condiciones ambientales P.boldus desarrolla respuestas
ecofisiológicas, para superar la época adversa.
Se evaluaron algunas respuestas ecofisiológicas de P.boldus, bajo condiciones de
restricción hídrica. Para esto se estableció un ensayo de restricción hídrica controlada con
60 plantas, de 3 años de edad. Las plantas se pusieron en macetas de 9 litros y bajo
condiciones naturales de verano, en la Región Metropolitana. Se seleccionaron 40 plantas
que fueron sometidas a riego restringido (TR), llegando hasta un 20% de la capacidad
hídrica de la maceta (CHM) y 20 se mantuvieron por sobre el 85% de CHM (TC). En TR y
TC se determinó: el potencial hídrico al alba (Ψa), contenido hídrico relativo al alba (CHRa)
y parámetros derivados de las curvas presión/volumen (P/V) como: potencial de presión a
100% turgor (ΨPt), potencial osmótico a 100% turgor (π100), potencial osmótico a cero
turgor (π0), contenido hídrico relativo a cero turgor (CHR0) y módulo de elasticidad (ε). Se
midió mensualmente el incremento en longitud del ápice (L) y el incremento del diámetro a
la altura del cuello (DAC). Además, se evaluó la biomasa total, por componente y la
relación parte aérea/parte subterránea (Pa/Ps), al inicio y término del período de
restricción hídrica.
Cuando el CHM alcanzo un 55%, el Ψa de TR fue significativamente más negativo que en
TC y sólo cuando el CHM fue menor al 20% a un CHRa del 59% el ε fue menor en TR,
mientras que el π100 y π0 no mostraron diferencias entre los tratamientos. No se vio
afectado L en TR, no así el DAC que fue significativamente menor a TC. Finalizado el
ensayo los valores de biomasa subterránea y total, sólo aumentaron significativamente en
TC. Sin embargo la relación Pa/Ps disminuyó en ambos tratamientos, siendo menor el
valor de TC. La distribución de biomasa indica que P.boldus da prioridad al crecimiento
radicular por sobre la parte aérea, independiente del estado hídrico en que se encuentre.
Además los resultados muestran que, P.boldus realizaría ajuste elástico, para superar la
condición de restricción hídrica impuesta.Peumus Boldus (Boldo) is an endemic tree of Chile which commonly grow in a
Mediterranean climate. This specie usually has to tolerate adverse summer periods, due to
the elevated radiation, high temperatures and lack of rain. These environmental conditions
produce in P.boldus different ecophysiological response for surpass the adverse periods.
Different ecophysiological responses were evaluated from P.boldus under restrictive water
conditions. To achieve this aim, a restrictive controlled essay was established using 60
plants of three year old. These plants were put into plant pots of nine liters and exposed to
summer conditions in the metropolitan region. From the 60 plants, 40 were selected to be
watered restricted (water restriction plants=Wr), reaching till 20% of the water plant pot
capacity (WPC). The other 20 plants were continuously well watered (well watered
plants=Ww) and maintained over 85% of the WPC. In Wr and Ww, the following items
were measured: predawn water potential (Ψa) and its relative water content (RWCPd), and
the parameters derived from pressure/volume curves as pressure potential at full turgor
(ΨFt) osmotic potential at full turgor (π100) and loss point (π0), relative water content at
turgor loss point (CHR0) and elasticity modulus (ε). In addition, it was monthly measured
the shoot increment (L) of the main axis and the diameter at the height of collar (DHC).
Finally, was evaluated the total biomass, by component and the shoot/root ratio at the
beginning and at the end of water restrictive period.
When the WPC reached 55%, the Ψa of the Wr was significantly more negative than in
Ww, and only when the WPC was under 20% to a RWCPd of 59%, the ε was minor in Wr;
meanwhile, the π100 and π0 did not show any difference between the treatments. The Wr
height increment was not affected; on the other hand, the DHC was significantly minor in
Wr. At the end of the water restrictive period, the root and the total biomass values only
showed a significantly increment in Ww. However, the shoot/root ratio decrease in both
treatments, being minor in Ww than in Wr. The biomass distribution show that P.boldus
gives priority to the biomass root growing up than to the aerial part of it, independently of
the water state. Furthermore, the results indicate that P.boldus would do an elastic fitting
for tolerate the restrictive water condition imposed
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
- …
