1,721,160 research outputs found
Computer-Generated Holographic Beams for the Investigation of the Molecular and Circuit Function
No full textMethod for generating a lattice of Bessel beams with arbitrarygeometries and optical properties with one single optical element
No full textEffects of environmental enrichment on recognition memory in zebrafish larvae
No full textZebrafish (Danio rerio) constitute a useful model for studying memory function and impairment in vertebrates and are now widely used in translational research. On the one hand, the adoption of simple, fast and reliable tests such as novel object recognition (NOR) has increased our knowledge considerable about memory mechanisms in animals. On the other hand, in many model organisms, exposure to environmental enrichment, especially during the early stages of development, affects various cognitive functions. Evidence for the effects of environmental enrichment on zebrafish has been accumulating rapidly, but most of this evidence has been collected in adult subjects. We compared larvae raised in either an enriched or barren environments and measured their memory performance at 14-days post-fertilization. Initially, subjects were allowed to familiarize with two identical novel objects (i.e., pattern of 2D-geometrical figures). After a time interval, larvae faced a two-choice task presenting the same objects paired with a new one. As a measure of recognition memory, we exploit the tendency of individuals to explore a novel object over a familiar one. Our results indicate that larvae from the barren environment spent more time exploring familiar stimuli than novel ones, showing the innate presence of recognition memory capacity in zebrafish larvae. Conversely, subjects bred in a visually enriched environment explore both familiar and novel stimuli almost equally. The increase of exploratory behavior and, consequently, the reduction of avoidance to the novel object may explain the performance shown by larvae exposed to an enrichment environment compared to the larvae bred in a barren environment. Taken together, these results confirm that early-stage zebrafish possess complex visual discrimination capacities and that rearing subjects in a structurally complex environment might hinder memory performance by reducing their neophobic response
Integrating Biodiversity Conservation Into Vineyard Management Strategies: A Bibliometric Analysis and Systematic Literature Review
No full textIndagine sulla colonizzazione da Campylobacter termofili in allevamenti di tacchini da carne: risultati preliminari.
No full textSince epidemiology of thermophilic campylobacters in turkeys has been scarcely investigated, we carried out longitudinal studies aimed at identifying potential sources and vehicles of Campylobacter infection in commercial meat turkey farms. A preliminary sampling in turkey breeders flocks was carried out in order to detect a Campylobacter-positive flock. Then, a monitoring of 2 meat turkey farms rearing the progeny of the positive turkey breeders flocks was performed. Meconium was collected from day-old chicks at the hatchery and then faecal swabs were collected three times at the farm (at the beginning, middle and end of the production cycle). Farm sampling consisted of multiple drinking water samples, surface swabs, air, overshoe samples in the anteroom and inside the house, and insects. Sampling was also carried out during downtime. Isolation and identification of Campylobacter spp. were performed by a conventional culture method and a multiplex end-point PCR assay, respectively. Day-old chicks tested negative for thermophilic campylobacters, whereas C. jejuni and C. coli were subsequently isolated from birds throughout the entire cycle in all flocks except for one. Both Campylobacter species were also frequently isolated from drinkers, flies and lesser mealworms. Water, air from inside the house, and surface swabs were always negative. These findings suggest that vertical transmission could not be an important source of flock infection, whereas horizontal transmission should be considered the major route for colonization of turkeys, as campylobacters were found in several environmental sources
Study of Diffusion Controlled Polymerization through the Analysis of the Molecular Weight Distribution
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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
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