1,721,514 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
Somatostatin immunoneutralization in the chicken: immunogen development and effect on growth
No full textDispelling 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
Histomonas meleagridis ('blackhead') moleculaire karakterisatie, diagnose en preventie
No full textHistomonas meleagridis (blackhead): moleculaire karakterisatie, diagno se en preventie Histomonosis (blackhead) wordt veroorzaakt door de flagellaire protozo ön Histomonas meleagridis en is één van de belangrijkste aandoening en bij kalkoenen. De infectie gebeurt via de caeca, maar verspreidt zich daarna via de poortader naar de lever en eventueel naar andere organen. De parasiet veroorzaakt karakteristieke necrotische letsels in en verdi kkingen van de caecale mucosa, een typische kaasachtige prop in het caec ale lumen en necrotische hepatitis. Bij kalkoenen kan deze ziekte tot 10 0% mortaliteit leiden, terwijl dit bij andere hoenderachtigen zoals kipp en slechts in beperkte mate tot dood zal leiden, maar wel kan bijdragen tot algemene morbiditeit. Door het grote aanbod aan farmacologische midd elen in de 20ste eeuw, werd H. meleagridis lange tijd onder controle geh ouden en was er weinig behoefte om onderzoek te verrichten naar de paras iet. Hierdoor zijn er momenteel enkele cruciale hiaten in de kennis van H. meleagridis, voornamelijk op moleculair vlak. Op het einde van de vor ige eeuw en in het begin van deze eeuw werd het gebruik van alle farmaco logische middelen tegen histomonosis bij voedsel-producerende dieren ech ter in de Europese markt verboden, waardoor deze ziekte opnieuw een opma rs kende in deze landen. Hierdoor is het doel van dit doctoraat een nieu w middel te vinden dat pluimvee, en voornamelijk kalkoenen, kan bescherm en of eventueel behandelen tegen histomonosis. Vooreerst werd de ef ficiëntie van paromomycine als therapeutisch en als profylactisch middel getest tegen H. meleagridis bij kalkoenen. Verder werden de eerste s tappen gezet tot de moleculaire karakterisatie van de parasitiet, wat to t identificatie van kandidaatantigenen zou kunnen leiden voor vaccinontw ikkeling. Een vaccin dient echter een protectieve immuunrespons te induc eren, wat voor H. meleagridis nog niet opgehelderd is. Daarom werd in dit doctoraat de protectieve waarde van een systemische antistoffenresp ons tegen de parasiet bij kalkoenen onderzocht. Daarnaast is het tot op heden moeilijk vast te stellen hoe ver H. meleagridis verspreid is, a angezien de gevoeligheid bij hoenderachtigen voor deze parasiet sterk ve rschilt en verschillende hoenderachtigen als dragerdieren kunnen optrede n. Bovendien kunnen de symptomen van en de letsels in de organen van zie ke dieren fout geïnterpreteerd worden. Hierdoor is een laatste doel van dit doctoraatsonderzoek een gevoelige en specifieke diagnostische test t e ontwikkelen voor de detectie van H. meleagridis.status: Publishe
Naar duurzame Aquacultuur: Omega Baars in recirculatie systemen
No full textWith juvenile Omega Perch Therapon barcoo, the substitution of dietary fish oil with plant oils in diets with 20% fishmeal didn’t result in a growth deficiency or a difference in fillet recovery. However, when fishmeal free diets were used, there was a certain growth reduction, indicating that juvenile Omega Perch require a minimum amount of about 0.5% of n-3 HUFA in their diet. These dietary n-3 HUFA can be supplied with Schizochytrium; low dietary amounts of these protists don’t cause an inferior fillet quality. DHA from Schizochytrium is stored more efficiently in the fish compared to DHA from fish oil, and the fillet recovery increased when fish were fed Schizochytrium. Both fat and the fatty acid spectrum of the fish fillet are directly proportional to the respective content of the feed. Omega Perch can have up to 3.75% n-3 PUFA in their fillet, one of the highest values ever recorded in fish. A whole body fatty acid survey and qRT-PCR demonstrate that Omega Perch can desaturate and elongate n-3 PUFA towards long chained n-3 HUFA.
After hatching from the egg, Omega Perch start exogenous feeding at 3 DPH (Days Post Hatching) and are only 0.3 mg in size. In RAS, the optimal weaning age when Artemia are supplied is at 12 DPH with a further 3 days of co-feeding with dry micro diets before a switch to 100% dry feed can occur. Feeding the larvae the first 3 days of exogenous feeding with smaller sized AF Artemia before switching to EG Artemia resulted in a lower survival (>1%) compared to feeding only EG Artemia (9% survival). This indicates that smaller sized live prey would not result in better survival. When larvae are weaned at 13 DPH, they weigh around 12 mg and reach 140 mg (fingerling size) after 3 weeks of exogenous feed consumption. When the correct feeding strategy is applied, an average survival and fast growth is obtained, to ensure adequate fingerling production.
In RAS without denitrifying reactors, nitrate levels determine the water exchange rate. Denitrification occurs in anaerobic heterotrophic reactors with an adequate C/N ratio. In a RAS with Omega Perch fed a 40% protein diet, a sequence batch reactor (SBR) with an alternating anaerobic and aerobic phase can reduce the water exchange from 550 to 30 l per kg of feed. Furthermore, the solids waste stream of the drum filter can be used for adequate denitrification. Dephosphatation occurs, but is rather small compared to denitrification. The SBR has a small but negative impact on other water parameters (CO2, NH3 and NO2) which should be taken into account when dimensioning the components of the RAS system. Off flavour producing bacteria occur in the SBR, however it is unclear if the SBR is responsible for a net increase in off flavour, since adsorption of off flavour in the sludge of the SBR might occur.
In short, we report some criteria for sustainable aquaculture of a new species for the European consumer: Omega Perch . Without the use of dietary fishmeal and fish oil, and a low water usage, Omega Perch grows well in recirculation systems. An adequate dietary n-3 source enables a high concentration of n-3 in its flesh.status: Publishe
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