1,720,961 research outputs found
Attività NADPH-diaforasica e NO sintetasi in Megoura vciae Buckton (Homoptera, Aphididae)
No full textSono state condotte indagini istochimiche e immunoistochimiche per la localizzazione rispettivamente dell'attività NADPH-diaforasica e della uNOS (universal NOS), della nNOS e della iNOS. in organi e tessuti dell'afide Megoura viciae. Gli anticorpi anti-uNOS, comunemente utilizzati per gli insetti, non sono risultati particolarmente idonei in questa specie di afidi, mentre una immunoreattività molto più estesa è stata ottenuta con gli anticorpi anti-iNOS e anti-iNOS
Occurrence of nitric oxide synthase in Megoura viciae Buckton (Homoptera, Aphididae): an histochemical and immunohistochemical localisation
Full text linkNitric oxide (NO) is known to be involved in many physiological reactions of insects. We analysed NOS localisation in aphids of the species Megoura viciae by means of histochemical reaction for the NADPH-diaphorase activity and immunohistochemical methods for uNOS, nNOS and iNOS. The obtained data provided a complex and peculiar pattern of NOS distribution in cells and tissue of M. viciae.The histochemical reaction for NADPH-diaphorase was an indicative, but not exact marker of NOS localisation in aphids. The use of anti uNOS antiserum (frequently applied in insects) was of limited value in our specimens, whereas more satisfactory results were obtained with anti nNOS and iNOS antisera of human origin. The results of Western blot analysis confirmed the immunohistochemical ones, showing an aphid protein that reacted strongly with the polyclonal antibody anti-iNOS and anti-nNOS while a similar protein band was weakly immunoreactive with the polyclonal antibody anti-uNOS. Our results suggest that NO, prevalently synthesised by calcium/calmodulin-dependent isoform, plays important physiological roles both in adult and embryological stages of aphids. The data of principal interest was NOS presence in bacteriocytes, cells that host symbiotic prokaryotes belonging to the species Buchnera aphidicola, and in nuclei of adipocytes and gut cells
Effects of atrazine on corn aphids
No full textThe effects on animal feeding on resistant plants of widespread use of herbici were studied utilizing Sipha maydis and Schizaphis graminum, which feed on phloem sap of corn, as test-organism. Atrazine is toxic to aphids, and this effects is manifest rather rapdly. The most striking damage occured in the digestive apparatus
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
Studio dell’attività biologica di semiochimici per una strategia innovativa di biocontrollo di Cacopsylla pyri (Hemiptera, Psyllidae).
No full textCacopsylla pyri è uno dei più importanti insetti dannosi al pero in Emilia Romagna poiché causa una significativa riduzione qualitativa e quantitativa della produzione. Il contenimento del fitofago, basato su un numero limitato di fitofarmaci, è spesso insoddisfacente e con risultati variabili soprattutto quando manca il contributo naturale del suo predatore, Anthocoris nemoralis. E’ stato pertanto intrapreso uno studio per valutare l’attività biologica di semiochimici intraspecifici (feromoni sessuali) ed interspecifici (sostanze volatili di origine vegetale) su C. pyri per una strategia innovativa di biocontrollo di tale fitofago. Lo studio si articola in due linee di indagine; la prima ha previsto l’ottenimento, sia da femmine che da maschi di C. pyri, di estratti cuticolari la cui attività biologica è stata valutata mediante indagini elettroantennografiche (EAG) e comportamentali (olfattometro a Y). Le risposte EAG hanno evidenziato come le miscele di composti volatili presenti negli estratti ottenuti da femmine fossero in grado di stimolare il sistema olfattivo dei maschi. Indagini olfattometriche successive hanno dimostrato come i maschi fossero significativamente attratti sia dalle femmine che dal loro estratto cuticolare, evidenziando la presenza di feromoni sessuali in corso di identificazione. La seconda linea di indagine riguarda l’individuazione di sostanze volatili emesse da diverse cultivar di pero in grado di influenzare il comportamento di C. pyri e di conseguenza la scelta della pianta ospite. Tutte le sostanze volatili saggiate hanno evocato risposte EAG: alcune risposte sono risultate significativamente più elevate per entrambi i sessi
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
- …
