1,721,507 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
Distribution of calbindin-D28k immunoreactivity inthe deep nuclei of the bottlenose dolphin (Tursiopstruncatus) amygdaloid complex
No full textDistribution of injectates in the thoracic paravertebral space of the dog and cat: A cadaveric study
Full text linkBackground: Thoracic paravertebral block (TPVB) entails injecting a local anesthetic inside the thoracic paravertebral space (TPVS). Loss of resistance to air injection (air-LOR) was the first technique described in humans to locate the TPVS. To date, no study has investigated the spread of any substance after injection into the TPVS using the air-LOR technique nor has described the cranial and caudal limits of the space. Aim: To identify the boundaries of the TPVS, to determine whether the air-LOR technique is reliable for the identification of the TPVS and to examine the relationship between the volume of injectate and its spread. Methods: After a preliminary phase, the thorax of five cat and five dog cadavers was accessed and eviscerated. After TPVS probing, the polyurethane foam was injected, and the cranial and caudal borders were recorded after its maximum spread. Different volumes of a mixture of new methylene blue and ioversol were injected in the TPVS after its localization with a Tuohy needle and air-LOR technique in fourteen dog and six cat cadavers. Lateral radiographs of the vertebral column were used to document needle positioning, spread pattern and extension. The thorax of these subjects was then accessed and eviscerated to observe and record the spread of the mixture. Results: Injecting a dye into the TPVS, localized by an air-LOR technique, resulted in multi-segmental and often bilateral subpleural staining of paravertebral, intercostal, and dorsal mediastinal structures in dog and cat cadavers. The lateral radiographs most often showed a mixed cloud-like and linear spread pattern, which could be a predictor of the longitudinal spread of the dye. The foam injected into the TPVS at the cranial and the caudal level revealed anatomical communication with the cervical, axillar, and lumbar paravertebral regions. Conclusion: TPVS localization by air-LOR technique and injection results in a longitudinal multi-segmental spread in dog and cat cadavers. The communication of the TPVS with the axillary and lumbar regions could be of clinical interest for the brachial plexus and the lumbar intercostal nerve blocks in a clinical setting
Distribution of Nitrergic Neurons in the Dorsal Root Ganglia of the Bottlenose Dolphin (Tursiops truncatus).
Full text linkDorsal root ganglia (DRGs) contain the cell bodies of primary afferent neurons that transmit sensory information from the periphery into the spinal cord. Distinct populations of DRG neurons have been characterized by a variety of different immunohistochemical markers. A subpopulation of ganglionic neurons containing neuronal nitric oxide synthase (nNOS), an enzyme known to generate nitric oxide, has been detected in a number of mammalian species. Despite previous studies, no information is known on the presence and exact distribution of nNOS-immunoreactive neurons in the DRGs of the bottlenose dolphin. In this investigation, immunoperoxidase for nNOS was used to determine the distribution and the perikaryal size of nitrergic neurons in the DRGs of this species. Double immunofluorescence protocol was used to determine the percentage of nNOS-immunoreactive (IR) neurons over the total primary afferent neurons. In addition, double immunostaining was used to verify whether there was colocalization of nNOS with substance P (SP). In all DRGs, a subpopulation of small- and medium-sized neurons (about 9%) exhibited nNOS immunoreactivity. Data analysis revealed that the majority of nNOS-IR neurons (81.3%) expressed SP. The density of nNOS-immunoreactive and nNOS/SP-double immunopositive cells was relatively constant throughout the ganglia. However, as observed in others mammals, the number of nitrergic neurons decreased in the caudalmost DRGs. Our results, in conjunction with previous observations, suggest that nNOS-IR neurons may be involved in the afferent transmission of visceral and nociceptive information as well as in the regulation of the vascular tone
Corrosion detection of carbon steel in water/oil two phases environment by electrochemical noise analysis
No full textThe aim of this paper is to demonstrate the effectiveness of the Electrochemical Noise Analysis to detect the onset of corrosion phenomena in a very high resistivity medium. Tests were carried out on carbon steel electrodes immersed in a water/mineral oil two phases environment with high concentration of CO2, different aqueous/organic phase ratio, sulphide content between 0 and 0.5 g/l and pH between 1 and 5. The evolution of corrosion phenomena were followed by collecting current and potential noise between three nominally identical electrodes. The noise data were analysed in the time and in the frequency domain. In spite of a great loss of sensitivity of the method with respect to tests performed in aqueous solution, the data indicate a good agreement between the standard deviations and the power level of Power Spectra Density (PSD) of current and potential noise signals and corrosion rates by means of weight loss. The values of the PSD slope, indicate the form of corrosion. The effect of water/oil ratio, sulphide concentration and pH on the corrosion rate was determined. Finally two methods to increase the sensitivity of the Electrochemical Noise are proposed
Immunohistochemical Localization of Substance P And Cholecystokinin in the Dorsal Root Ganglia and Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)
No full texthe presence of substance P (SP) and cholecystokinin (CCK) immunoreactive neurons was examined in the bottlenose dolphin dorsal root ganglia (DRGs) and spinal cord by immunohistochemical techniques. SP-positive and CCK-immunoreactive neurons were respectively approximately 50% and 1% of the total number of ganglion cells examined and especially belonged to small and medium-sized cell populations. Using double labeling techniques we observed that SP- and CCK-immunoreactivity coexisted in a very low number of primary afferent neurons (2.7%). Few SP-immunoreactive (IR) neurons (2.7%) were also CCK-positive. On the contrary, 65% of CCK-immunoreactive neurons contained SP. Interestingly, we observed CCK-immunoreactive satellite glial cells located around large cell class somata. Virtually no SP-IR and CCK-positive neurons were surrounded by peripheral CCK-immunoreactive satellite glial cells. The SP-IR and CCK-positive nerve fibers were particularly conspicuous in the superficial layers of the spinal cord. The present study indicates that SP and CCK only partially overlap in the thoracic, lumbar, and caudal DRGs of the bottlenose dolphin, suggesting that the majority of SP-IR ganglion neurons are lacking in CCK-immunoreactivity. The role of SP-containing DRG neurons is discussed also in relation to the huge vascular spinal retia mirabilia typical of cetaceans
Nitrergic neurons in the spinal cord of the bottlenose Dolphin (Tursiops truncatus).
No full textNitric oxide (NO) is a freely diffusible gaseous neurotransmitter generated by a selected population of neurons and acts as a paracrine molecule in the nervous system. NO is synthesized from l-arginine by means of the neuronal nitric oxide synthase (nNOS), an enzyme requiring nicotine adenine dinucleotide phosphate (NADPH) as cofactor. In this study, we used histochemical and immunohistochemical techniques to investigate the distribution of NADPH-diaphorase (NADPH-d) and nNOS in the spinal cord of the bottlenose dolphin (Tursiops truncatus). Cells with a fusiform-shaped somata were numerous in the laminae I and II. The intermediolateral horn showed darkly-stained cells with a multipolar morphology. Neurons with a multipolar or fusiform morphology were observed in the ventral horn. Multipolar and fusiform neurons were the most common cell types in lamina X. Nitrergic fibers were numerous especially in the dorsal and intermediolateral horns. The presence of nitrergic cells and fibers in different laminae of the spinal cord suggests that NO may be involved in spinal sensory and visceral circuitries, and potentially contribute to the regulation of the complex retia mirabilia. © 2013 Wiley Periodicals, Inc
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