1,720,967 research outputs found
Circadian release of pigment-dispersing factor in the visual system of the housefly, Musca domestica
No full textIn the present study we examined profiles of nerve fiber varicosities containing dense core vesicles (DCVs) in the distal medulla of the housefly's optic lobe using electron microscopic methods. These profiles are infrequent among other neuronal profiles and do not contain presynaptic specializations for the release of DCVs. Presynaptic elements surrounded by electrontranslucent vesicles were only occasionally detected, whereas synaptic input sites to the profiles containing DCVs were never observed. Among the varicosities in the distal medulla, those immunoreactive to pigment-dispersing hormone (PDH) are most numerous. The DCVs of PDH-immunoreactive (PDH-ir) varicosities differ by size from DCVs of other profiles. Moreover, in the day/night cycle PDH-ir varicosities show differences in structure revealing the rhythmic accumulation and release of PDF. There were fewer PDH-ir DCV per varicosity profile in flies fixed 1 hour after lights-on than in flies fixed 1 hour after lights-off. Moreover, at the beginning of the day all DCVs harbored an electron-dense matrix, while at the beginning of the night numerous electron-lucent DCVs were observed. By applying a bath stimulation with a high potassium concentration we also showed that depolarizing events are involved in peptide release in the medulla. After potassium treatment immunolabeling with anti-PDH serum was weaker and PDH-ir varicosities were smaller and more distant from each other than in control animals
Communication among photoreceptors and the central clock affects sleep profile
Full text linkLight is one of the most important factors regulating rhythmical behavior of Drosophila melanogaster. It is received by different photoreceptors and entrains the circadian clock, which controls sleep. The retina is known to be essential for light perception, as it is composed of specialized light-sensitive cells which transmit signal to deeper parts of the brain. In this study we examined the role of specific photoreceptor types and peripheral oscillators located in these cells in the regulation of sleep pattern. We showed that sleep is controlled by the visual system in a very complex way. Photoreceptors expressing Rh1, Rh3 are involved in night-time sleep regulation, while cells expressing Rh5 and Rh6 affect sleep both during the day and night. Moreover, Hofbauer-Buchner (HB) eyelets which can directly contact with s-LNvs and l-LNvs play a wake-promoting function during the day. In addition, we showed that L2 interneurons, which receive signal from R1-6, form direct synaptic contacts with l-LNvs, which provides new light input to the clock network.Fil: Damulewicz, Milena. Jagiellonian University; PoloniaFil: Ispizua, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ceriani, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Pyza, Elzbieta M.. Jagiellonian University; Poloni
Cryptochrome is a regulator of synaptic plasticity in the visual system of Drosophila melanogaster
Full text linkDrosophila CRYPTOCHROME (CRY) is a blue light sensitive protein with a key
role in circadian photoreception. A main feature of CRY is that light promotes an
interaction with the circadian protein TIMELESS (TIM) resulting in their ubiquitination
and degradation, a mechanism that contributes to the synchronization of the circadian
clock to the environment. Moreover, CRY participates in non-circadian functions
such as magnetoreception, modulation of neuronal firing, phototransduction and
regulation of synaptic plasticity. In the present study we used co-immunoprecipitation,
yeast 2 hybrid (Y2H) and in situ proximity ligation assay (PLA) to show that CRY
can physically associate with the presynaptic protein BRUCHPILOT (BRP) and that
CRY-BRP complexes are located mainly in the visual system. Additionally, we present
evidence that light-activated CRY may decrease BRP levels in photoreceptor termini in
the distal lamina, probably targeting BRP for degradation.bruchpilot, circadian clock, tetrad synapses, active zone, photoreceptor
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
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