1,720,962 research outputs found
Forms of lateralisation in common wall lizards
No full textLateralisation, i.e. left/right differences in behaviour associated with CNS asymmetries, is widely distributed in vertebrates and shows striking correspondences in different taxa: the right eye is usually used in response to food targets, whilst left eye use is associated with complex layouts and objects. Lateral eyes species, as fishes and very often sauropsids, are good models for investigating the occurrence of lateralisation, because of minimal binocular view and the frequent minimal connections between the two cerebral hemispheres. We aimed at ascertaining the possible existence of visual lateralisation forms in the Common wall lizard (Podarcis muralis), belonging to a family (Lacertidae) neglected from that point of view. We report results obtained in several experiments carried out in different contexts: the predatory context, the anti-predatory context, and the exploratory one. When the lizards faced mealworm larvae as prey they preferred watching them with the right eye. This occurred when the lizards detected the prey at the end of either arm of a T-maze or behind a transparent barrier to detour, as well as when at the centre of a circular arena. Conversely, when the lizards escaped from a refuge after visual and sound stimulation feigning a predator, they chose to use the left eye to monitor the threatening stimulus during the escape run.
The escape direction was slightly and very frequently to the right. Escaping to the right direction allowed lizards to turn the head back to the left in order to have a wider visual field with the left eye to monitor the supposed predator. Left eye use preference was ascertained even when the lizards explored a new environment, such as a maze, an open field, and an empty circular arena. We can then confirm that even in Lacertidae different tasks are monitored by different eyes and, therefore, processed by different cerebral hemispheres, maybe for the need of short- or long term memory processing
Lateralization in the predatory behaviour of the Common wall lizard (Podarcis muralis)
No full textEctotherms have been shown being lateralized as well as mammals and birds. This is particularly evident in visual lateralization, i.e. the different use of the eyes, leading to use a specific eye to observe specific kind of stimuli and to process them with the correspondent contralateral hemisphere. Several lower vertebrates are facilitated in this from the lateral position of the eyes, enabling them to carry out more tasks simultaneously, controlled by different eyes and relative hemispheres. Predatory responses seem usually mediated by the right eye/left hemisphere in fishes, amphibians and some sauropsids, but there are no strong evidences of this in lizards. Eighteen wild males of the Common wall lizard Podarcis muralis were tested individually in captivity to ascertain whether they are lateralized to look at prey with a specific eye. The lizards were gently induced entering a 30-cm long central arm of a T-maze which led to a 44.5-cm long arm cross-arm at whose extremities there were two identical prey, Tenebrio molitor larvae, familiar to the lizards. We recorded what direction the lizards chose to reach the prey and the frequency and duration of head turning, indicative of looking either prey with the left or the right eye. We found that individuals show being lateralized at individual level. The preferred direction taken to reach the prey is the right for the majority of those (4 of 5) showing an evident preference, indicating also a possible form of laterality at population level. In addition, lizards maintained the same head side of the direction taken turned for more time towards the prey than the opposite head side, revealing an eye preference for observing this kind of cue. Our study demonstrates how males of Podarcis muralis have a visual lateralization to capture prey. Furthermore, it is another support to the hypothesis of vertebrate lateralization derivation from a common ancestor
Agriculture Management and Soil Fauna Monitoring: The Case of Emilia-Romagna Region (Italy)
Full text linksoil quality. Here we analyzed soil arthropods community in several agricultural managements (arable land, grassland, vineyard and orchard) located in the Emilia-Romagna region (Italy), whose land was especially exploited for intensive agriculture, in order to state soil health and soil quality, in relation to crop types and management. The computation of the biological soil quality index QBS-ar revealed lower values in arable lands, easily due to management practices applied, in particular ploughing. On the other hand, the QBS-ar values associated to orchards and vineyards were higher: the grassy cover on soil and the reduced farming practices support soil microarthropod communities. Meadows were generally characterized by high index values, related to their age. The application of QBS-ar index as a tool to identify soil quality and, thus, soil functionality, was then confirmed. Starting with this type of approach, further analyses could be crucial to highlight differen
Lateralization when monitoring predators in the wild: a left eye control in the common wall lizard (_Podarcis muralis_)
No full textLateralization is the function specialization between left and right brain hemispheres. It is now ascertained in ectotherms too, where bias in eye use for different tasks, i.e., visual lateralization, is widespread. The lateral eye position on the head of ectotherm animals, in fact, allows them to observe left/right stimuli independently and allows lateralized individuals to carry out left and right perceived tasks at the same time. A recent study conducted on common wall lizards, Podarcis muralis, showed that lizards predominantly monitor a predator with the left eye while escaping. However, this work was conducted in a controlled laboratory setting owing to the difficulty of carrying out lateralization experiments under natural conditions. Nevertheless, field studies could provide important information to support what was previously found in the laboratory and demonstrate that these traits occur in nature. In this study, we conducted a field study on the antipredatory behavior of P. muralis lizards. We simulated predatory attacks on lizards in their natural environment. We found no lateralization in the measure of eye used by the lizard to monitor the predator before escaping from it, but the eye used was probably determined by the relative position of the lizard and the predator just before the attack. This first eye used did not affect escape decisions; lizards chose to escape toward the nearest refuge irrespective of whether it was located to the lizard’s left or right side. However, once they had escaped to a refuge, lizards had a left eye–mediated bias to monitor the predator when first emerging from the refuge, and this bias was likely independent of other environmental variables. Hence, these field findings support a left eye–mediated observation of the predator in P. muralis lizards, which confirms previous findings in this and other species
Fault Diagnosis in VLSI IC's by Simultaneous use of Scanning Electron and Tunneling Microscopy
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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
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