1,720,987 research outputs found
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
Substance-specific influences of setting on drug reward: an ultrasonic vocalization study in rats self-administering heroin and cocaine.
No full textClinical and preclinical evidence indicate that the setting of drug use affects drug reward in a substance-specific manner (Caprioli et al. 2009; Badiani and Spagnolo 2013). When heroin and cocaine co-abusers, for example, report on the circumstances of drug use, they indicate distinct settings for the two drugs: heroin being used preferentially at home and cocaine preferentially outside the home (Caprioli et al. 2009; Badiani and Spagnolo 2013). Similar results were obtained in rats given the choice between these two drugs (Caprioli et al. 2007, 2008, 2009). Rats that live in the self-administration (SA) chambers (Resident rats) tend in fact to prefer heroin to cocaine, whereas rats that are transferred to the SA chambers only for the test sessions (Non-Resident rats) tend to prefer cocaine to heroin. The goal of this study was to investigate whether the affective value of cocaine and heroin changes as a function of the setting. It has been shown that rats emit ultrasonic vocalizations (USVs) in the range of 50-kHz when exposed to rewarding stimuli, whereas they emit 22-kHz USVs in the presence of aversive stimuli, suggesting that 50-kHz USVs reflect positive affective states (Burgdorf et al. 2000, 2001, 2008). In the present study, we recorded USVs in rats undergoing cocaine and heroin SA on alternate days. We found that Non-Resident rats emit more 50-kHz USVs when self-administering cocaine than when self-administering heroin. In contrast, Resident rats emit more 50-kHz USVs when self-administering heroin than when self-administering cocaine. These findings indicate that the setting of drug taking exert a substance-specific influence on the ability of drugs to induce a positive affective state
Behavioural and neuroendocrine effects of developmental exposure to a common organophosphate insecticide in two mouse strains: relevance for vulnerability to human neurodevelopment disorders.
No full textChlorpyrifos (CPF) is the most largely used organophosphate insecticide worldwide. Epidemiological studies have indicated that assumption of CPF by diet and indoor exposure at environmentally relevant doses affects behaviour and brain maturation in exposed children. We found that developmental exposure of the out bred CD1 mouse strain to low dose of CPF altered neonatal behaviour patterns, adult social responses and neuroendocrine markers in a sex-dimorphic fashion. In the present study the prenatal treatment schedule used for CD1 mice was applied to the inbred BTBR T+tf/J mouse strain, a validated model of autism-spectrum disorders. The etiology of autism is still obscure but it has become increasingly clear that both defective genes and environmental factors (including chemicals) concur to the pathogenesis of this clinical heterogeneous condition. BTBR mice exhibit an abnormal immune responses that may also contribute to a proper vulnerability to environmental insults.
Moreover while the BTBR mouse has been shown to exhibit behavioural patterns thought to be relevant to the core domains of ASD, it is unknown whether these behaviour, relevant to ASD, can be further exacerbated by the effects of environmental insults, such as chlorpyrifos exposure.
Pregnant BTBR mice were orally administered on gestational days 14-17 with either vehicle or CPF at a dose of 6 mg/kg/bw. Offspring of both sexes underwent neonatal assessment of sensorimotor milestones and ultrasound emission, and social investigation and/or courtship behaviour were investigated at adulthood. Our findings evidenced significant effects of CPF on neonatal behaviours and ultrasound emission with a different pattern of effects between CD1 and BTBR mice. BTBR-CPF males showed an abnormal courtship behaviour pattern of the receptive female, an effect not found in the CD1 males.
Analysis of mRNA expression of oxytocin, vasopressin and steroid receptors in hypothalamus and amygdala evidenced important baseline differences between the two strains, which might be relevant for their different behavioural phenotypes and susceptibility to neurotoxicants' effects
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
Sex-dimorphic behavioral and neuroendocrine effects of the organophosphate chlorpyrifos in a mouse model of autism spectrum disorders.
No full textAutism is a neurodevelopmental disorder characterized by impaired social and communicative skills and repetitive behaviors with a male-female ratio of 4:1. The etiology of autism results from complex interaction between multiple genes and diverse environmental contaminants.
Chlorpyrifos (CPF) is a widely diffused organophosphate insecticide. Recent epidemiological studies indicate that environmentally prenatal exposure to CPF in children can alter the morphology of some brain areas involved in cognitive and behavioural processes. Several rodent studies have confirmed that CPF developmental exposure influences serotonergic neurotransmission and neuroendocrine markers in hypothalamic and amygdaloidal regions in a sex-dimorphic fashion.
In the present study we analyzed the effects of low-dose developmental exposure to CPF in a mouse model of autism-spectrum disorders, the BTBR T+tf/J mouse strain, which displays several behavioral traits relevant to autism.
To this aim, pregnant BTBR mice were administered from gestational day 14-17 with either vehicle or CPF at a dose of 6 mg/kg/bw by oral gavages. Offspring of both sexes underwent early assessment of sensorimotor milestones and ultrasound emission. At adulthood, the social responses of females were assessed in a free social interaction test with a same-sex companion, whereas the courtship behavior of adult males with a sexually receptive female was analyzed.
Our findings evidenced significant effects of CPF on neonatal motor patterns and ultrasound emission, in the male offspring. At adulthood, CPF males showed an abnormal pattern of social investigation of the receptive female, associated to marked increase in the rate of ultrasonic vocalizations emitted during the courtship. Analysis of mRNA expression in hypothalamus and amygdala evidenced in CPF males a significant decrease of vasopressin receptor 1A in the hypothalamus and ERα in the amygdala, and a diminished expression of ERβ and oxytocin precursor in the hypothalamus.
These findings open the way for future experimental studies on the interaction among vulnerable gene backgrounds and environmental neurotoxicants in the etiology of sex-biased neurodevelopmental disorders.
Supported by: Project Italy/US 11US/11 and Italian Ministry of Health Grant (GR3), Young Researcher 2008, “Non-invasive tools for early detection of Autism Spectrum Disorders”
- …
