1,720,961 research outputs found
Growth and Yield of Rice (Oryza sativa L.) as Affected by Time and Ratio of Nitrogen Application at Jimma, South-West Ethiopia
No full text– Insufficient nitrogen supply in inappropriate
timing is an important constraint to productivity of upland
rice (Oryza sativa L.), and there is limited information
available on optimal timing of N application for upland rice
in Ethiopia including Jimma area. Field experiment was
conducted on three upland rice varieties (Gumara, Ediget
and Nerica-4) in a completely randomized block design with
3 replications to determine the effects of timing and ratio of
nitrogen application on growth and yield during the 2014
cropping season on acidic nitisol (soils possessing nitic
property) at the Jimma University, College of Agriculture
and Veterinary Medicine research site. The N-timing
treatments were: N1
(50% at sowing and 50% at active
tillering stage), N2
(25% at sowing + 50% at active tillering
stage and 25% at panicle initiation), N3
(25% at sowing +
25% at active tillering stage and 50% at panicle initiation),
and N4
(33% at sowing + 33% at active tillering stage and
33% at panicle initiation). The highest grain yields (1070
kg/ha), biomass yields (3333 kg/ha), total number of grains
per panicle, and harvest index were recorded from ‘Ediget’
variety at the N2 combination (25% at sowing + 50% at
active tillering stage and the remaining 25% at panicle
initiation), followed by N3 and N4 combinations. The lowest
grain yields (117 kg/ha) and biomass yields (767 kg/ha) were
recorded from Nerica-4 variety at the N2 combination.
Nerica-4 variety produced minimum grain and biomass
yields across all the N combinations. Most of the parameters
exhibited maximum performance under N2 and N3
combinations across all the varieties. The varietal treatments
had highly significant (P<0.001) effects on the total number
of panicles, grain yield, biomass yield and harvest index.
Grain yield was positively correlated (P<0.01) with plant
heights (r=0.68**), number of filled grains per panicle
(r=0.52**) and thousand grains weight (r=0.61**) and
negatively correlated with most of the traits. Number of
panicles was the most important component of yield,
accounting for about 87% of the variation in rice yield. Thus,
rice cultivation and its nitrogen fertilizer management in the
area is concerned, the variety ‘Ediget’ was recommended for
higher grain and biomass yields regardless of the N-timing
treatments. Concerning the N-timing treatments, the f
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
Evaluation of sorghum (Sorghum bicolor (L.) Moench) backcross nested association mapping populations under moisture stress at sheraro, northern ethiopia
No full textSorghum is one of the most important cereal crops in Ethiopia. Production and productivity
of Sorghum is constrained by frequent drought and prolonged dry spell especially over the
last two decades in Ethiopia leading to food insecurity. The aim of the current study was to
evaluate BCNAM populations for drought tolerance, analyze the genetics of traits and
identify genotypes with desirable drought tolerance traits. The experiment was conducted at
Sheraro, Northern Ethiopia. A total 1264 genotypes were evaluated using an alpha lattice
design with two replications. Analyses of variance for quantitative characters showed highly
significant difference among the progenies (P< 0.01) for all traits indicating possibility for
selection. Similarly, parental lines also exhibited significant difference (p<0.05) for most of
the traits except chlorophyll content at flowering, panicle width (cm), grain weight per
panicle (g) and number of panicles per plant. Some progenies were early flowering including
lines 32 (Teshale x IS14446) (61.525 days), 1226 (Teshale x IS32234) (62.9 days), 1099
(Teshale x IS16044) (64.53days), 749 (Teshale x IS14298 (66.04 days) and 305 Teshale x
IS15428 (69.01 days). Whereas, lines 673 (Teshale x IS3583) (79.03 days), 903 (Teshale x
IS16173)(77.68 days), 513 Teshale x IS22325 (75.2 days), 911 Teshale x IS16173 (73.73
days), and 37 Teshale x IS14446 (71.74 days) were late flowering. While the best performed
progenies in grain yield per panicle were 747TeshalexIS14298 (67.47g), 2 TeshalexIS14446
(63.87g), 107 TeshalexIS14446 (61.03g), 767 TeshalexIS14298 (58.54g) and 1239 Teshalex
IS32234 (55.89g) with the average yield of 38.21g per panicle. Traits with high GCV and
PCV values such as chlorophyll content at maturity, number of panicle per plant, grain
weight per plant and grain yield can be improved by simple selection. Chlorophyll content at
maturity, date of 50% flowering, date of 95% maturity, panicle length, shows high heritability
values indicate quick and visual selection is possible. Whereas chlorophyll content at
maturity, grain filling period and thousand seed weight were exhibited high GAM shows
additive gen action. Progenies 747, 479, 2, 702, and 914 were promising genotype for further
evaluation. Principal component analysis shows 24.33%, 13.82%, 12.32%, 9.63% and 7.43%
of the variation from PC1 to PC5 respectively with the cumulative variance of 67.53
Combining ability and heterosis estimation in elite sorghum [Sorghum bicolor (L) Moench] inbred lines under moisture stress conditions
No full texthe most important prerequisite in crop improvement is the selection of suitable parents,
which could combine well and produce desirable hybrids. However, lack of potential parents
and hybrids, limited genetic variation, narrow genetic base and information on the genetic
components are the most important limiting factors for sorghum yield improvement under
moisture stress. Therefore, the present study was conducted to determine the combining
abilities, heterosis, mean yield performance and gene action governing the quantitative traits
for yield and its components using line x tester mating design. The experimental materials
consisted of fifteen parents along with their twenty six hybrids and one standard check. The
experiment was laid out using alpha lattice design with two replications at Mieso and Kobo
during the cropping season of 2018/19. Combined analysis of variance revealed highly
significant differences due to genotypes for all studied traits over locations, which indicates
the availability of substation genetic variation among genotypes. Based on general combining
ability analysis, inbred line 3 and 4 were identified as best general combiners for both days to
flowering and plant height traits whereas inbred line 2 and 7 were identified as best general
combiners for stay green traits. Thousand seed weight showed best general combiners in
inbred line 6, 10 and 12. The hybrid crosses 4x14, 8x15 and 11x14 were identified as best
specific combiners for grain yield while hybrid 1x15 was best specific combiner for days to
flowering, days to maturity, panicle length, panicle width and thousand seed weight. The
estimates of general and specific combining ability revealed the preponderance of nonadditive gene action since the ratio of general combining ability to specific combining ability
was less than unity for all the traits under study except for plant height. The maximum grain
yield was obtained from a hybrid 4x14 (6.32 t/ha) followed by hybrid 8x15(5.92 t/ha), 1x15
(5.88 t/ha), 13x14 (5.78 t/ha) and 6x15 (5.57 t/ha) with the average value of 5.0 tones/ha
which had higher mean value than the mean of the parents and the check. Among the hybrids,
8x15 recorded maximum heterosis (112.41%) over the mid parents, hybrid 1x15 revealed
maximum heterosis (68.71%) over the better parent whereas 4x14 recorded maximum grain
yield with (30.71%) heterosis over the standard check for grain yield. The two heterotic
groups were identified based on their specific combining ability effects and also three
heterotic groups were identified based on their general combining ability effects to develop
superior hybrids from broad base and suitable parents. Finally, based on mean yield
performance, heterotic response, combining ability estimates and nature of gene action for
grain yield and its components, inbred lines 4, 9, 10, 11, 12, 13 and the hybrid crosses 4x14,
8x15, 1x15, 11x14, 11x15, 13x14, 6x15 were found to be the most promising and potential
varieties which could be exploited commercially after critical evaluation for their superiority
and yield stability across the locations over years
Evaluation of sorghum (Sorghum bicolor (L.) Moench) backcross nested association mapping populations under moisture stress at sheraro, northern ethiopia
No full textSorghum is one of the most important cereal crops in Ethiopia. Production and productivity
of Sorghum is constrained by frequent drought and prolonged dry spell especially over the
last two decades in Ethiopia leading to food insecurity. The aim of the current study was to
evaluate BCNAM populations for drought tolerance, analyze the genetics of traits and
identify genotypes with desirable drought tolerance traits. The experiment was conducted at
Sheraro, Northern Ethiopia. A total 1264 genotypes were evaluated using an alpha lattice
design with two replications. Analyses of variance for quantitative characters showed highly
significant difference among the progenies (P< 0.01) for all traits indicating possibility for
selection. Similarly, parental lines also exhibited significant difference (p<0.05) for most of
the traits except chlorophyll content at flowering, panicle width (cm), grain weight per
panicle (g) and number of panicles per plant. Some progenies were early flowering including
lines 32 (Teshale x IS14446) (61.525 days), 1226 (Teshale x IS32234) (62.9 days), 1099
(Teshale x IS16044) (64.53days), 749 (Teshale x IS14298 (66.04 days) and 305 Teshale x
IS15428 (69.01 days). Whereas, lines 673 (Teshale x IS3583) (79.03 days), 903 (Teshale x
IS16173)(77.68 days), 513 Teshale x IS22325 (75.2 days), 911 Teshale x IS16173 (73.73
days), and 37 Teshale x IS14446 (71.74 days) were late flowering. While the best performed
progenies in grain yield per panicle were 747TeshalexIS14298 (67.47g), 2 TeshalexIS14446
(63.87g), 107 TeshalexIS14446 (61.03g), 767 TeshalexIS14298 (58.54g) and 1239 Teshalex
IS32234 (55.89g) with the average yield of 38.21g per panicle. Traits with high GCV and
PCV values such as chlorophyll content at maturity, number of panicle per plant, grain
weight per plant and grain yield can be improved by simple selection. Chlorophyll content at
maturity, date of 50% flowering, date of 95% maturity, panicle length, shows high heritability
values indicate quick and visual selection is possible. Whereas chlorophyll content at
maturity, grain filling period and thousand seed weight were exhibited high GAM shows
additive gen action. Progenies 747, 479, 2, 702, and 914 were promising genotype for further
evaluation. Principal component analysis shows 24.33%, 13.82%, 12.32%, 9.63% and 7.43%
of the variation from PC1 to PC5 respectively with the cumulative variance of 67.53%
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
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