1,720,993 research outputs found
Cytological and electrophoretic analysis of DNA methylation in the holocentric chromosomes of Megoura viciae (Homoptera, Aphididae).
No full textChromosomal and purified DNA methylation patterns were determined in the holocentric chromosomes of Megoura viciae by treatment with MspI and HpaII. Both enzymes produced a clear C-like banding pattern but widely digested one telomere of the X chromosome, which appeared as heterochromatic after C-banding treatment and brightly fluorescent after chromomycin A(3) staining. Quantitative microfluorometric evaluations of DNA extraction performed on cytological preparations showed that both isoschizomers resulted in the same DNA extraction (about 30%). Contrary to what was found by in situ endonuclease treatment, the electrophoretic patterns of purified and digested DNA showed that digestion with MspI was slightly more extensive than that with HpaII in a zone of fragments ranging from 23 to 9 kb. This result indicates that aphid chromatin is not wholly unmethylated. The discrepancy between electrophoretic and cytological data has been explained by taking into consideration that DNA fragments with high molecular weights could be cleaved in situ by the enzymes but not extracted from the chromatin
Sistema con turbogas e sorgente geotermica ad acqua dominante
No full textNel lavoro viene presenato uno studio analitico che tiene conto dell'influenza delle grandezze che caratterizzano il funzionamento di un sistema ibrido ottenuto dall'integrazione di un gruppo turbogas con una sorgente geotermica ad acqua dominante, con lo scopo di individuarne le tipologie che realizzano le migliori prestazioni. L'analisi svolta mostra come il sistema ibrido proposto rappresenti una soluzione interessante per la rivalutazione delle sorgenti geotermiche energeticamente depresse, fornendo prestazioni in linea con i sistemi convenzionali a combustibile fossile di maggiore efficienza e garantendo nel contempo un ridotto impatto ambientale
Engine and load torque estimation with application to electronic throttle control
No full textElectronic throttle control is increasingly being considered as a viable alternative to conventional air management systems in modern spark-ignition engines. In such a scheme, driver throttle commands are interpreted by the powertrain control module together with many other inputs; rather than directly commanding throttle position, the driver is now simply requesting torque - a request that needs to be appropriately interpreted by the control module. Engine management under these conditions will require optimal control of the engine torque required by the various vehicle subsystems, ranging from HVAC, to electrical and hydraulic accessories, to the vehicle itself. In this context, the real-time estimation of engine and load torque can play a very important role, especially if this estimation can be performed using the same signals already available to the powertrain control module. In this paper we present two methods to estimate the instantaneous indicated torque, combustion by combustion, and the vehicle load torque; we also present some preliminary results. The first method is based on the reconstruction of the in-cylinder pressure based on the measured engine block vibration. The second one exploits a nonlinear estimation technique, in which the difference between the instantaneous measurement of crankshaft angular velocity and an estimate of the same velocity, based on a model of the engine, forms the input to a sliding-mode observer. Experimental results of both methods have been obtained in an engine test cell on a two-cylinder compression-ignition. Copyright © 1998 Society of Automotive Engineers, Inc
The genome of the lepidopteran Mamestra brassicae has a vertebrate-like content of 5-methyl-cytosine (5mC)
No full textThe genome of the lepidopteran Mamestra brassicae has a vertebrate-like content of 5-methyl-cytosine (5mC
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
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