1,721,036 research outputs found
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
Genetic improvement of Leucaena spp and Acacia koa Gray as high-value hardwoods
Full text linkStudies on genetic improvement of Leucaena and Acacia koa Gray were undertaken in Hawaiʻi from 1999-2003. There studies were described in two sections. The first section focused on research of Leucaena hybrids, which included vegetative propagation of Leucaena hybrids, hybrid yield trials, and chromosome doubling of diploid Leucaena species. Different hybrids rooted differently. Cuttings with more leaf presence had higher rooting frequency, better root qualities, and quicker root initiations. Leafless cuttings did not root under a mist system. One-node cuttings rooted as well as bi-nodal cuttings. Cuttings from younger (25-45 days old) regrown shoots rooted better than cuttings from older shoots (>45 days old). All hybrids rooted poorly in winter. Difficult-to-root hybrids rooted well after the treatments of etiolation. Three hybrid yield trials using clones of hybrids were carried out at three locations, Waimanalo of O'ahu, and Hamakua and Kona of Hawaiʻi Island. Seedless hybrid K1000 grew best at warm areas of Waimanalo and Kona, but grew poorly at cool area of Hamakua in terms of DBH, height, and wood volume. Two tetraploid hybrids, KX3 cl2 (L. leucocephala xL. diversifolia) and K156 x K376 (L. diversifolia x L. pallida) were among the fastest-growing hybrids at Waimanalo and Hamakua. The method (0.1% colchicine treatments on seedlings) to induce tetraploid Leucaena species was effective. Larger, thicker and darker leaflets, and larger flower heads of induced tetraploids were observed. The second section focused on studies of koa, which included cytological study of koa, vegetative propagation, koa mortality and tolerance to wilt disease, and prediction of breeding values of koa. No variations in chromosome number were found among three koa types and populations. The chromosome number of koa was identified as 2n=52 among all populations examined. Koa vegetative propagation was feasible at juvenile stage. Rooting ability of cuttings declined quickly with the increase of the age of cuttings. Cuttings of most families did not root at transitional and mature stages, and they did not respond to the treatments of growth regulators. Only cuttings of two families from Hawaiʻi Island responded to auxins well with a moderate increase in rooting percentage at transitional and mature stages. Etiolation treatments appeared to have some effects on rooting at transitional stage. Koa survival rates in progeny trials declined steadily over the years. The mortality appeared to be mainly caused by koa wilt disease. The survival rates of koa families were analyzed and used to assess family tolerance to the disease. Great variation in survival rate was found among the families. Family selection based on survival rate was conducted. To rank the growth performance of koa families in progeny trials, breeding values of DBH at the age of 4 years were predicted in 4 progeny trials using BLP (Best Linear Prediction) method. Family ranking and selection based on predicted breeding values were conducted. Genetic gains of selection were calculated based on family selection.Ph.D
Corn leaf aphid and polysora rust resistance in tropical maize
Full text linkThis research includes two separate studies both of which incorporated generation mean analyses to interpret genetically the resistance to com leaf aphid and polysora rust in tropical maize. The first study focused on resistance to corn leaf aphid in tropical sweet corn inbred Hi38-71. An inoculation technique using hair-pin clip cages and infestation quantification method using digital image analysis were developed for this study. During the study, a heavy natural infestation of com leaf aphids occurred in a seed production nursery. Yield loss by ranged from 38.9% to 98.8%, with an average loss of 71.7%. The clip-cage method was effective in distinguishing resistant and susceptible plants under field conditions. Resistance to com leaf aphid from Hi38-71 appeared to be monogenic and recessive. Aphid reproduction and population growth were measured on four different genotypes of varying aphid tolerance. Aphids on Hi38-71 had poorest performance over all aspects of growth and reproduction examined. Difference in number of progenies produced and days to 50% mortality appeared to account for most of the difference observed in the genetic study. The second study estimated genetic parameters for polysora rust resistance in Hi38-71. Hi38-71 exhibited moderately high resistance to polysora rust as well as resistance to com leaf aphid. Generation mean analysis showed that epistatic interactions of [aa] and [dd] along with simple dominance and additive gene effects were involved in controlling resistance in Hi38-71 to polysora rust. It is concluded that polysora resistance breeding cannot be based on selection of a single parent but a hybrid-breeding or reciprocal recurrent selection approach appears justified. The tropical sweet corn inbred, Hi38-71 is a sib line of Hi38 which was bred from a bt-1 conversion of AA8sh2. AA8sh2 was studied for its resistance to corn leaf aphid in 1970's in Hawaii and was converted to common rust resistance, Rd1-D which broke down due to evolved racial variation of the pathogen. Hi38-71 is thus of particular value in sweet corn breeding for tropical regions. This is due not only to its resistance to corn leaf aphid and polysora, but to its high sweet corn qualities and generally good combining abilities.M.S
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
When Teacher Educator Practices What Is Preached: Peer Teaching and Evaluation in a Field-Based English Methods Course.
Full text linkA teacher educator with an over-sized class describes an experiment with peer teaching. The class of \u27fifteen students was divided into groups of three, defined as mutual support groups; with each member contributing to and responsible for the performance of others. The first task assigned these trios was to identify desirable competencies, compare them with the other small groups in the class, and finally arrive at mutually agreed upon goals upon which evaluation of performance could be based. In the field these students were assigned to different schools so the group could receive maximum exposure to different teachers, students, and perspectives on curriculum. Shortly before an active week of student teaching, the trios met to discuss plans for their mini-units, to schedule days for cross-visitation, and to share concerns about likely problems with students or cooperating teachers. Observation and evaluation of members of the group took place during student teaching. The author concludes that this method of instruction, properly organized and supervised, has considerable merit
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