1,721,035 research outputs found
Simultaneous identification of species and molecular forms of the Anopheles gambiae complex by PCR-RFLP.
No full textFor differential identification of sibling species in the Anopheles gambiae Giles complex (Diptera: Culicidae), including simultaneous separation of M and S molecular forms within An. gambiae Giles sensu stricto, we describe a PCR-RFLP method. This procedure is more efficient, faster and cheaper than those used before, so is recommended for large-scale processing of field-collected larval and adult specimens to be identified in malaria vector studies
THE ANALYSIS OF THE SEQUENCE OF AN INTRON UPSTREAM THE KDR MUTATION SUPPORTS REPRODUCTIVE ISOLATION OF ANOPHELES GAMBIAE S.S MOLECULAR FORMS. 3RD
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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
Sequence analysis of Intron I of the voltage gated Sodium channel gene supports reproductive isolation of Anopheles gambiae s.s. molecular forms.
No full textMolecular evidence of incipient speciation within Anopheles gambiae s.s. in West Africa.
No full textIncipient speciation in the malaria mosquito Anopheles gambiae s.s.: Sequence analysis of intron I of the voltage-gated sodium channel gene
No full textIncipient speciation processes within Anopheles gambiae s.s. have been revealed by polytene chromosome analysis (Coluzzi et al., 1985, Boll Zool 52: 45-63) and, more recently, by sequence analysis of different rDNA regions (della Torre et al., 2001 Insect Mol Biol, 10: 9-18; Gentile et al., 2001, Insect Moi Biol, 10: 25-32). The latter has shown the existence in West Africa of two non-panmictic molecular forms, Sand M, which in the northern part of their range of distribution coincide with chromosomal forms Savanna/Bamako and Mopti, respectively. Recently, Chandre et al. (1999, Parassitologia 41: 319-322) found that in the voltage-gated sodium channel gene, the point-mutation associated with kdr (knock-down resistance), which confers resistance to pyrethroids and DDT, shows a non-homogeneous distribution in the two molecular forms. Further, preliminary sequence analysis of the intron I upstream the kdr mutation showed two nucleotide differences respectively associated with Sand M forms (Weill et al., 2000, Insect Mol Biol, 9: 451-455). We sequenced 535 bp of intron I in more than 100 specimens from 10 West African countries from Senegal to Angola. Specimens had been previously karyotyped, assigned to a chromosomal form, identified as molecular form S or M and characterized for the presence of the kdr allele. At position 702 a T and a C were consistently associated with Sand M form, respectively. At position 896 a C was fixed in all S samples analysed, while M samples showed either a fixed C Iike S samples or an A/C polymorphism, depending on the geographical origin of the samples. In S samples in which the kdr allele is present, no difference among kds/kds, kds/kdr and kdr/kdr genotypes was recorded at both sites. Kds/kdr specimens were found in a single M sample from Benin and resulted T/C heterozygotes at sites 702: this supports the hypothesis that the kdr and the intron alleles have been transferred from S to M through introgression Weill et al. (op. cit.). Microsatellite studies carried out on Sand M forms have revealed virtually no differentiation between chromosome arms except for the 2R (Lanzara et al. 1998, Proc. NatI. Acad. Sci., USA 95:14260-14265; Taylor et al. 2001, Genetics 157:743-750) and a single microsatellite closely Iinked to the rDNA region (Wang et al. 2001, Prac. Nat. Acad. Sci. USA 98: 1 0769-1 0774). The mutation at position 702 represents the first marker in an intron DNA region that consistently correlates over a wide geographic range with the rDNA markers used to define An. gambiae molecular forms. Interestingly, the voltage-gated sodium channel gene maps on Div. 20C, on the left arm of the chromosome 2 (Ranson et al., 2000, Insect Mol Biol, 9: 491-497), a chromosomal region associated neither with rDNA (X chromosome), nor with inversions (2R) used to define the chromosomal forms
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