1,721,059 research outputs found
LE FUNZIONI COMPLEMENTARI E ALTERNATIVE DEI TUBULI MALPIGHIANI DEGLI INSETTI
No full textComplementary and alternative functions of insects Malpighian Tubules
The Malpighian Tubules are gut regions where excretion takes place. However, there are other functions that Malpighian
Tubules can perform simultaneously with the excretion (i.e. complementary functions), and other functions that they can
perform suspending the excretion, and restoring it later (i.e. alternative functions).
The complementary functions are related to production of mucofibrils, minerals, brocosomes, defensive products and viscous substances for the protection of eggs and juvenile instars.
In some species, the phenomenon of bioluminescence takes place in Malpighian Tubules, and – even in this case – it can be
considered as a complementary function.
Furthermore, the alternative functions of Malpighian Tubules only relate to the production of substances for the construction
of the cocoon have been found
Sexual size differences and colour polymorphism of Rhynchophorus phoenicis in the Southwest region of Cameroon
Full text linkA total of 174 specimens of the African palm weevil Rhynchophorus phoenicis (F.) were sampled during 2010, in eight different
localities of the Southwest region of Cameroon. Male and female weevils were measured (body length, abdomen length, abdomen
width, pronotum length, pronotum width, head size, and length from tip of rostrum to antennal insertion), and the different pronotum
patterns are described. Statistical analysis shows that all morphometric parameters correlate with body length in both males
and females, and seven pronotum pattern types are identified, three of which are new. African palm weevil adults show sexual
dimorphism: abdomen and head size are significantly greater in females, while pronotum length is significantly greater in males.
No statistical differences in the frequencies of pronotum pattern types were seen between males and females, or among localities.
A significant difference was seen for the abdomen width between two localities
Ultrastructure of the female reproductive apparatus of the egg parasitoid Gryon pennsylvanicum (Ashmead) (Hymenoptera, Platygastridae)
No full textAbstract
The growing interest in Leptoglossus occidentalis, the conifer seed bug pest accidentally introduced into Europe in the 1990s, led us to investigate the female reproductive structures of the hymenopteran platygastrid Gryon pennsylvanicum, which is its candidate antagonist for biological control programmes. Our study revealed a genital apparatus with some characteristic features, such as an unusual length of the oviduct (divided into a long proximal and a short distal tract), the absence of accessory glands and the presence of a spermatheca provided with a small spermathecal gland. The ultrastructural investigation revealed that the shorter part of the common oviduct is involved in ion uptake whereas the longer part has two cell types with secretory function: the former with dense bodies and the latter with granular particles. The secretory contents of both are released into the oviduct lumen. The granular particles are formed in a complex of modified endoplasmic reticulum and appear as virus-like particles
Ecologica comportamentale dell'istrice Hystric cristata L., 1758 in un'area costiera del Mediterraneo
No full textDottorato di ricerca in biologia animale (zoologia). 12 ciclo. A.a. 1997-99. Coordinatore Romano Dallai. Tutore Sandro LovariConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
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
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
- …
