1,720,994 research outputs found
Rohevintide hematoloogilised tervisenäitajad: individuaalse varieeruvuse põhjused ja vastused immuunsüsteemi manipuleerimisele
Full text linkVäitekirja elektrooniline versioon ei sisalda publikatsioone.Immuunökoloogia eesmärgiks on välja selgitada mehhanismid, mis seovad immuunsüsteemi teiste elutähtsate funktsioonidega ja seletada selle kaudu looduses esinevat varieeruvust vastuvõtlikkuses haigustele. Kuigi valdavalt nõustutakse, et immuunvastus on organismile kulukas, pole veel kaugeltki selge, milles immuunvastuse hind väljendub ja millised mehhanismid immuunvastuse hinna teiste tunnustega seovad.
Minu doktoritöö eesmärkideks oli (1) kontrollida mõne laialt kasutusel oleva meetodi sobivust ning rakendamisvõimalusi immuunökoloogilistes uuringutes ning (2) leida vastuseid teadusharus viimasel ajal kerkinud võtmeküsimustele. Töö esimeses pooles uurisin lindude immuunökoloogias immuunsüsteemi töö hindamiseks laialt kasutusel oleva meetodi (PHA süstimine) pikajalisi mõjusid, erinevate oksüdatiivse staatuse parameetrite ajalist varieeruvust ning omavahelisi korrelatsioone ning vangistuses elavate rohevintide sobivust immuunökoloogiliste uuringute jaoks. Töö teises osas uurisin karotenoidide rolli immuunvastuse reguleerimises, immuunvastuse oksüdatiivset hinda ning karotenoidsetes ja melaniinsetes sulestikuornamentides sisalduvat informatsiooni. Oma töös kasutasin mudelorganismina loodusest püütud rohevinte.
Leidsin, et karotenoididel võib tõepoolest olla roll immuunvastuse ja selle hinna kujunemisel, kuid selle rolli uurimise muudavad keerukaks mitmed organismisisesed tegurid. Samuti näitasin, et oksüdatiivsed kahjustused moodustavad tõepoolest osa immuunvastuse hinnast. Linnu võimet tulla toime oksüdatiivse stressiga peegeldavad tema mustad sulestikulaigud, kuid mitte karotenoidsed ornamendid.
Oma töö tulemusena veendusin, et rohevinte võib pidada heaks immuunökoloogia mudelorganismiks ning nende abil võib leida vastuseid mitmetele immuunökoloogia võtmeküsimustele. Rohevindid taluvad hästi vangistust ning nende sulestikuornamendid võimaldavad uurida signaaltunnuste ausust tagavaid mehhanisme. Rohevintidel esinev krooniline koktsiidinakkus on kergesti jälgitav ja manipuleeritav, mis võimaldab uurida immuunvastuse hinna probleeme ning immuunsüsteemi seoseid teiste elutähtsate funktsioonidega. On selge, et koos immuunökoloogia võtmeküsimustele vastuste otsimisega peab paralleelselt toimuma ka meedodite väljatöötamine, testimine ja uurimine. Vaid nii on võimalik ühendada üksteisest pealtnäha kaugel asuvad distsipliinid – immunoloogia ja ökoloogia – ning nende teadusharude integreerimise abil leida vastuseid küsimustele, mida kumbki haru eraldi lahendada ei suudaks.The primary goal of immunoecology is to find out the factors, both extrinsic and intrinsic, leading to changes in immune system function, and understand how these changes affect disease susceptibility. Although it has now been accepted that immune responses are costly, the question about the currencies used for paying this cost has remained poorly understood.
The main aims of my thesis were (1) to assess the suitability and utility of several widely used methods in ecological research of immunity and oxidative balance systems, and (2) to study some of the most intriguing questions in avian immunoecology. In the first part, I tested the long-term impact of a classic immunoecological technique (PHA skin test), correlations between several indexes of oxidative status and their repeatability in time, and the suitability of wild-caught captive greenfinches for ecophysiological research. In the second part, I studied the association between carotenoids and immune function, oxidative costs of mounting an immune response, and the information content of plumage coloration. Captive greenfinches were used as model organisms.
I found that carotenoids may play a role in immune response and in the cost of immune activation, but studying this role is complicated because of several confounding intrinsic factors. I also showed that oxidative damage is a part of the costs of an immune response. According to my results, the bird’s ability to control oxidative stress is signaled with its black plumage ornaments, but not in carotenoid-based ornaments.
In conclusion, studying captive greenfinches seems to be a promising approach for answering many intriguing questions in immunoecology. Their good captivity tolerance allows studying a wild species in controlled laboratory conditions. Their plumage ornaments allow studying honesty of signal traits. Their common infection with coccidians is easy to follow and manipulate, making them good models for studying the costs of immune activation and the associations between immune system and other traits. At the same time, although some model systems and methods might seem to be widely accepted and technically completed, work with old and new methods must always continue in order to find possible flaws, better interpretation possibilities and new solutions. Continuous methodological work will eventually help to bind together immunology and ecology, and this synthesis will enable scientists to find solutions to many questions that both disciplines separately would fail to answer
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
