1,721,020 research outputs found
Macrocyclops albidus (Copepoda: Cyclopidae) for the biocontrol of aedes albopictus and culex pipiens in Italy
No full textThe aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would require more recolonization intervention to maintain mosquito control during the season
Molecular systematics and origin of the Mediterranean sea rock-pool mosquitoes of the aedes mariae (diptera: culicidae) complex
No full textMosquitoes belonging to the Aedes mariae complex, including Aedes mariae (Sergent & Sergent), Aedes zammitii (Theobald), and Aedes phoeniciae (Coluzzi & Sabatini), are among the few animals
inhabiting the extreme habitat of sea rock pools. Morphological analysis of these species and crossing experiments conducted in laboratory and natural conditions inferred the occurrence of three taxa
with a parapatric distribution along the coasts of the Mediterranean Basin. To date, however, genetic characterization of the three species within the Ae. mariae complex and an assessment of their interspecific
differentiation are lacking. In this study, we used both nuclear (i.e., 14 allozymic loci) and mitochondrial genetic markers (i.e., sequences of the cytochrome oxidase I and II genes) to genetically
characterize the three species belonging to the complex. Then, we used mitochondrial markers to inferphylogenetic relationships between the species and estimate the time to most recent common ancestor
(TMRCA). The allozymic and mitochondrial markers showed the occurrence of three distinct gene pools, namely, Ae. mariae, Ae. zammitii, and Ae. phoeniciae. The TMRCAs for the entire in-group were
estimated to have occurred during the early Pleistocene (i.e., mean node age of 1.739 million years ago). An important role of Pleistocene climatic changes could be suggested in the origin of the species of the Ae. mariae complex and in shaping their pattern of intraspecific genetic diversit
wPip Wolbachia contribution to Aedes albopictus SIT performance: Advantages under intensive rearing
No full textAs a part of a project aiming at the suppression of the mosquito vector Aedes albopictus, a specific Ae. albopictus line producing sterile males, ARwP, was tested for its suitability to intense rearing conditions compatible with mass production and field release. This line was developed by the Italian National Agency for New Technologies, Energy and Sustainable Economic Development thanks to the artificial infection with a heterologous Wolbachia strain, resulting in a bidirectional incompatibility pattern with wild-type Ae. albopictus. ARwP was reared under Standard Operating Procedures at the Centro Agricoltura Ambiente and compared with a wild-type strain in terms of time of pupation onset, production of male pupae in the following 24 h and mechanical sexing efficacy. Mating competitiveness of ARwP males was also evaluated in comparison with irradiated wild-type males in large field enclosures. ARwP males demonstrated a significantly shorter time of pupation onset, a higher rate of production of male pupae in the following 24 h and a lower percentage of residual contaminant females when applying mechanical sexing procedures. In addition, ARwP males were more efficient than wild-types in competing for wild-type females in large enclosures, thus inducing a level of sterility significantly higher than that expected for an equal mating competitiveness. These results encourage the use of this Ae. albopictus strain as suppression tool against Ae. albopictus based on considerations thoroughly discussed in the manuscript
Exploring protandry and pupal size selection for Aedes albopictus sex separation
Full text linkBackground: We explored the possibility to improve male/female separation (sexing) in Aedes albopictus by selection of two strains, one toward increasing sex dimorphism and another toward increasing protandry. In the laboratory we selected and crossed small males with large females to exploit dimorphism, and early pupating males with late pupating females to exploit protandry. Results: While selection for enhanced dimorphism was not a profitable character, the selection for enhanced protandry up to F10 produced significant improvement in the time interval between male and female pupation. By collecting the pupae at 24 h from the beginning of pupation, without any sieving operation, we obtained about 28.50% of pupae (calculated in relation to the estimated initial number of first instar larvae used), vs 26.49% we had in the control strain, and, more interestingly, when checking the sex ratio of these pupae we observed a presence of females of 0.92% vs 23.02% in the control strain. We also modified our egg hatching protocol from the previous standard procedure that required keeping the eggs in the glass hatching container overnight (for about 14-16 h) to a new protocol where eggs are kept in the hatching container for 4 h in order to obtain more synchronized larvae. This was possible without any reduction in the egg hatching rate. Conclusions: In Aedes albopictus it is possible to develop hyper-protandric strains useful to produce male pupae without applying other sexing systems. This represents a considerable achievement assisting the Sterile Insect Technique application, allowing improvement of the current sexing method based on mechanical separation. More investigations are under way in order to further enhance the male productivity capacity of the strain and to determine whether the selection has any impact on the male fitness parameters
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
Establishment of a satellite rearing facility to support the release of sterile Aedes albopictus males. I. Optimization of mass rearing parameters
No full textThe vector species Aedes albopictus (Skuse, 1894) was recorded in Turkey for the first time, near the Greek border, in 2011 and a high risk of expansion towards Aegean and Mediterranean coasts of Turkey was estimated. A preliminary study was planned to evaluate the possibility of creating a satellite mass rearing facility for this species and manage a larval rearing procedure by using the new mass-rearing technology proposed by the International Atomic Energy Agency (IAEA). For this purpose, the effects of different larval densities (1, 2, 3 and 4 larvae per ml) on the preimaginal development were evaluated by observing pupal, adult and male productivity using life cycle trials. Geometric morphometric analyses were also performed to define all phenotypic differences that occurred on the wing size and shape morphology of adult stage at the four different rearing conditions tested. A high pupation productivity was obtained with a larval density of 2 larvae/ml while adult emergence ratio was not affected by the densities tested. No significant difference was observed in shape of the wings among different densities in males and females. Nevertheless, a significant difference in female's centroid sizes was observed between the treatment groups 1-2 and 3-4 larvae/ml and in males centroid size reared at 1 larvae/ml versus the other densities
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
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