105,097 research outputs found
Selection of antibodies for intracellular function using a two-hybrid in vivo system
No full textExpression of antibodies inside cells has been used successfully to ablate protein function. This finding suggests that the technology should have an impact on disease treatment and in functional genomics where proteins of unknown function are predicted from genomic sequences. A major hindrance is the paucity of antibodies that function in eukaryotic cells, presumably because the antibodies fold incorrectly in the cytoplasm. To overcome this problem, we have developed an in vivo assay for functional intracellular antibodies using a two-hybrid approach. In this assay, antibody, as single-chain Fv (scFv) linked to a transcriptional transactivation domain, can interact with a target antigen, linked to a LexA-DNA binding domain, and thereby activate a reporter gene. We find that several characterized antibodies can bind their target antigen in eukaryotic cells in this two-hybrid format, and we have been able to isolate intracellular binders from among sets of scFv that can bind antigen in vitro. Furthermore, we show a model selection in which a single scFv was isolated from a mixture of half a million clones, indicating that this is a robust procedure that should facilitate capture of antibody specificities from complex mixtures. The approach can provide the basis for de novo selection of intracellular scFv from libraries, such as those made from spleen RNA after immunization with antigen, for intracellular analysis of protein function based only on genomic or cDNA sequences
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Seasonal fluctuations in populations of Hypogastrura rossi (Salmon) and Isotomina thermophila (Axelson) in a Taita pasture
No full textA 15-month field survey of the population fluctuations of two dominant species of Collembola in a pasture soil at Taita was made, and these fluctuations related to temperature and moisture. The species studied were Hypogastrura rossi (Salmon) 1941 and Isotomina thermophila (Axelson) 1900. The work also involved controlled laboratory studies on the influence of temperature and humidity on the life-histories of H. rossi and I. thermophila.
From field data, frequency, dominance and density values were calculated for H. rossi and I. thermophila. Both species are aggregated in the soil - individuals of H. rossi being more highly aggregated than individuals of I. thermophila. Numbers of these species, which fluctuate seasonally, reached maximum abundance in spring - H. rossi in September, I. thermophila in November. Field data suggested that when compared with I.thermophila H. rossi prefers cooler and moister conditions.
The age distributions of the populations of H. rossi and I. thermophila were found to differ, prereproductives forming the highest proportion of the H. rossi population, reproductives the highest proportion of the I. thermophila population.
Growth of H. rossi and I. thermophila conforms to Dyar's Rule (Dyar, 1890). The rate of embryonic development of H. rossi is faster than that of I. thermophila at lower temperatures (7-14°C) but is slower at higher temperatures (15-25°C). At all humidities tested, specimens of H. rossi survived for greater lengths of time without food than specimens of I. thermophila
Hypogastrura distincta Axelson 1902
No full textHypogastrura distincta (Axelson, 1902) Syn.: Hypogastrura itaya Kinoshita, 1916 Material examined. Four females and six males, China: Tibet, Leiwuqi County, side of highway from Enda Town to Binda Town, 6.viii. 1997, collection number 9397, coll. Ming Wu; Three females and three males, China: Tibet, Chayu County, Jigong town, 18.vii. 1997, collection number 9395, coll. Ming Wu. Diagnosis. Microsetae and macrosetae moderately differentiated. Abd. IV–VI with knobbed macrosetae. Integumentary granulation fine. Labrum with four rounded papillae and 4 /5, 5, 4 setae. Maxilla as H. viatica - type. Ant. IV with simple apical bulb and dorsally with 4–5 curved and thin sensilla. Ant. I with seven setae, without p seta. Tibiotarsi I–III with 3, 3, 4 knobbed tenent hairs respectively. Unguis with an inner tooth, without lateral teeth. Unguiculus with small but distinct basal lamella. Dens with five setae. Length ratio of dens: mucro as 3.2–3.5: 1. Ventral tube with 4 + 4 setae. Tenaculum with 3 + 3 teeth. Remarks. The species Hypogastrura distincta has been found mainly in the Holarctic region so far (North America, Europe, Korea and Japan), and also in the Oriental region (Nepal). It is reported from Tibet for the first time here. The species is easily identified by the character combination of knobbed or clavate macrosetae on Abd. IV–VI and 3, 3, 4 tenent hairs present on tibiotarsi I–III. The Tibetan specimens are very close to those from Korea (Lee 1979) and Russia (Babenko et al. 1994) in body dorsal chaetotaxy and moderate differentiation between macrosetae and microsetae. They slightly differ from Alaskan specimens (Fjellberg 1985) in the lateral macrosetae on Abd. IV–VI being weakly knobbed and m 2 seta on Abd. V weakly knobbed or pointed rather than distinctly knobbed as in specimens from Alaska. Ecology. Found in leaf litter.Published as part of Jiang, Jigang & Chen, Jian-Xiu, 2008, A new species and a new species record of Hypogastrura (Collembola: Hypogastruridae) from China, pp. 47-54 in Zootaxa 1846 on page 49, DOI: 10.5281/zenodo.18331
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
Fully Turbulent Mean Velocity Profile for Purely Viscous non-Newtonian Fluids
No full textThe characteristic near wall behavior of turbulent flow of purely-viscous non-Newtonian fluids is discussed for both power-law (P.-L.) and Herschel-Bulkley (H.-B.) rheological models. A proper scaling is presented for H.-B. fluids to establish an analogy with power-law fluids with same flow index. To provide reference data for turbulent flow of non-Newtonian fluids, DNS simulations of power-law fluids are conducted in a rectangular channel for a large range of power-law indices ( = 0.5, 0.69, 0.75, 0.9, 1, 1.2). The DNS data show that the mean velocity profile in the viscous and logarithmic layers follow expressions of the form and respectively, where shows a logarithmic dependency on the flow index.Comparison with some experimental data shows the above formulation to be valid for Reynolds numbers (based on shear velocity) as high as 1000
H-index and research evaluation: A suggested set of components for developing a comprehensive author-level index
No full textThe H-index has been investigated in various studies; this index has many strengths that have made it popular. However, it also has weaknesses, due to which other indicators have been developed. This study aims to identify the strengths and weaknesses of the H-index and provide the minimum set of necessary components for developing a comprehensive author-level index. In this systematic literature review, Scopus, PubMed, Web of Science, Emerald, and ProQuest databases were searched to identify relevant studies. From the number of 14,253 retrieved studies, after two stages of screening, 81 studies were selected according to the eligibility criteria for data extraction. The findings of the study led to the identification of 15 strengths in the three categories of Quality Features, Simplicity, and Suitability, and 13 weaknesses in the six categories of Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation for H-index. Finally, 28 components were identified as the minimum set of necessary components to develop a comprehensive author-level index to help evaluate researchers more realistically and fairly. The minimum components that need to be considered in developing a comprehensive author-level index can be proposed as follows: Quality Features, Simplicity, Suitability, Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation
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