1,720,960 research outputs found
New enemies: contribution of Culex perexiguus in the transmission dynamic of West Nile virus
No full textVector-borne pathogens like West Nile virus (WNV), an emerging zoonotic arbovirus, are strongly influenced by mosquito community dynamics. WNV is maintained between birds and mosquitoes, with humans and other mammal species (such as equids) as dead-end hosts. In Spain, the role of Culex perexiguus as main vector of WNV is gaining significance over Cx. pipiens due to differences in feeding behavior, and vector competence, and ecological preferences that affect WNV transmission. Using a SEIR (Susceptible-Exposed-Infectious-Recovered) model, we examined how mosquito abundance and feeding preferences impact WNV spread in a Mediterranean region. Our results suggest that, under the conditions simulated, Cx. pipiens alone is unlikely to sustain WNV transmission in the study area, whereas Cx. perexiguus may contribute more substantially to outbreak dynamics. Increased avian-feeding preferences were associated with higher outbreak intensity, although the basic reproduction number (R0) remained below one in all scenarios. Sensitivity analyses highlighted that bite rates and abundance of Cx. perexiguus are key drivers of WNV spread in our model. Furthermore, a dilution effect was observed when Cx. pipiens fed more frequently on dead-end hosts, which contributed to lowering R0. Our findings underscore the need for species-specific vector surveillance to inform public health interventions and control strategies for WNV and other mosquito-borne diseases.This study was funded by the projects PID2022-142803OA-I00 and LEO23–2–10078, awarded to MF by the Spanish Ministry of Science and Innovation and the BBBVA Foundation (2023 Leonardo Grant for Researchers and Cultural Creators), respectively. The BBVA Foundation accepts no responsibility for the opinion, statements and contents included in the project and/or the results thereof, which are entirely the responsibility of the authors. MF is supported through a Ramón y Cajal postdoctoral contract (RYC2021–031613-I) from the Spanish Ministry of Science and Innovation. EF is funded by the MUSA – Multilayered Urban Sustainability Action project, which is supported by the European Union’s NextGenerationEU under the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment Line 1.5: Strengthening research structures and creating R&D “innovation ecosystems,” and establishing “territorial leaders in R&D”; Fundación BBVA [LEO23–2–10078]; Next Generation Foundation [Multilayered Urban Sustainability Action project]; Ministry of Science and Innovation [RYC2021–031613-I].Peer reviewe
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
MATHEMATICAL MODELLING TO INVESTIGATE INFECTIOUS DISEASE DYNAMICS AND CONTROL STRATEGIES
Full text linkInfectious diseases still represent one of the major threats for human health due to both their direct and indirect effects on public health and worldwide economies. Despite the current possibility to eradicate or control certain infections like smallpox, polio and measles, the increase in incidence of new infections (so called emerging diseases), or the increase in incidence or geographic range of ones that have existed previously (re-emerging diseases), poses a new threat to public health. To further complicate things, the role of animals in the insurgence and spread of new diseases is central. Of all emerging diseases indeed, the 60.3% originate by, or involve into their cycles, animals, and represent the so called zoonoses. The increase in number of emerging and re-emerging infections and their potential to fast spread into animal and human populations make central the development of tools to reduce human infection risk. Epidemiological studies become then central to understand the relationship among events, investigate their causal effects and understand risk factors. Despite of that, classical epidemiology, centred on the study of the relationships between events, show limits in the investigation of mechanisms underlying infection spread, and in considering the interactions among populations, thus possibly leading to simplistic and spurious conclusions. Mathematical modelling instead, and the development of a “dynamical epidemiology”, allows the investigation of dynamics of infections, thus providing us a mechanistic point of view to understand infection spread. The strengths of mathematical modelling applied to epidemiological studies are several. At first, they can investigate the extent to which an event can mechanistically influence another consequential event. This characteristic of mathematical modelling has a great application in public health, as it allows to prioritise interventions or studies on those events that have a major impact on disease outbreak. Another strength of mathematical modelling is its ability to describe the dynamics of an infectious disease by accounting for interactions among populations and sub-groups of populations within the same population. At least, mathematical modelling permits for theoretical investigations of mechanisms of transmission and to answer to “what if?” questions, allowing to explore theoretical scenarios which have not yet occurred or which needs to be preventively tested, like the application of an intervention strategy.
With the present work we then provide four applications of mathematical modelling to infectious disease. We focused on two wildlife-originating infections: West Nile virus (WNV) and baylisascariasis. Both infections are emerging or re-emerging in Italy and can represent a threat for human beings due to their possible severe outcomes. Due to the potential harm they are for human beings, a thorough surveillance and a wide intervention and control plans are ongoing both to promptly identify the presence and circulation of their causative agents and to reduce human infection risk. A full understanding of WNV cycle is fundamental to reduce human infection risk, but several knowledge gaps still exist, especially on the role played by different bird species involved in its spread. For both infections moreover, despite several are the control strategies proposed a quantitative analysis of their performance has never been performed. Aimed at filling these gaps, we developed a mathematical model to simulate WNV spread, and used it to explore mechanisms driving infection spread. We found birds recovery rate and mosquito biting rate having the major influence on disease spread and thus being the most urgent mechanisms to be investigated via field and laboratory experiments. Birds’ susceptibility and their competence to infection have a negligible influence on disease spread, thus making investigations to understand them of secondary importance. These results might be of aid also in defining the characteristics of a bird species to be a good WNV spreader, by focusing the attention on species that have a small recovery rate or are frequently bitten by mosquitoes. Moreover, we found a negative effect of birds’ abundance in affecting WNV prevalence in mosquitoes, further helping us in distinguishing among species that are suitable to have a role in WNV spread. We then exploited the built model to explore intervention strategies against WNV. We showed that a reduction of the vector population is more effective than a reduction of birds’ abundance in an area. In particular, the best efficacy is shown by the reduction of mosquito breeding sites, followed by the active elimination of their eggs and larvae. On the contrary, reducing the abundance of competent birds or their reproductive sites can obtain an increase in human infection risk. Similarly, we also studied the effectiveness of different intervention strategies to reduce the number of Baylisascaris procyonis eggs in the environment. The ingestion of B. procyonis eggs indeed is the cause of baylisascariasis, an infection that can have severe health consequences in human beings. With our work we explore the effects both in terms of efficacy (i.e., potential to eliminate eggs from environment) and efficiency (i.e. the timing needed) of three different intervention strategies. The interventions tested are: the active culling of raccoons, raccoons’ anthelmintic treatment and faeces removal. We found that raccoon culling might have the best and faster results, highlighting the importance of assessing the intervention on the base of an objective prove on its efficacy. With the proposed work then, we highlighted the role of mathematical modelling in epidemiological studies, by, at first, exploiting their potential to investigate the extent to which an event can influence another consequential event. Secondly, we used them to describe the dynamics of an infectious disease, by accounting for interactions among populations, and focusing on mechanisms underlying infection spread. Moreover, we also exploited them for theoretical investigations, like the simulation of the application of an intervention strategy to reduce human infection risk is.
In conclusion, mathematical modelling can widely help our understanding and management of infectious diseases through a new and different point of view from that provided by classical epidemiology. Mathematical modelling indeed includes the investigation of spreading mechanisms and non-linearity of interactions among individuals and subgroups of populations, thus allowing a more complete comprehension of diseases spread. The cooperation of diverse health professionals is fundamental to fully exploit both classical epidemiological studies and dynamics ones, and the effects of their cooperation can lead to a better knowledge of infections and a consequent reduction of human infection risk
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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