1,720,994 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
Evolution and function of hidden anti-predator signals
No full textHidden anti-predator signals (HAS) are hidden colour patterns in an otherwise cryptic prey; they are revealed upon encountering a predator. HAS include deimatic signals (DS) and flash signals (FS). DS are used when at risk of predation, typically after being discovered by a predator. Their position in the predation sequence (PS) differs by species. DS are often linked with deimatic behaviour, that boosts their efficiency. The use of DS in later stages of the PS occurs more often in defended prey, which may thus speed up predators' avoidance learning. In undefended prey, DS may trigger startle or fear responses, confusion or sensory overload in the predator, thereby pausing or stopping the attack. FS are exposed during the prey's escape, usually early in the PS before a predator detects the prey. This can cause a predator to form a wrong impression of the prey's appearance, making it harder to find. FS can also attract the predator's attention during pursuit, thus decreasing its chance of noticing an evasive manoeuvre. Dynamic FS, in which different colours alternate during movement, can make it hard to estimate the prey's position. The presence of both types of HAS is often linked with prey body size. The efficiency of FS is affected by the flight initiation distance. The efficiency of DS is related to...Skryté antipredační signály (SAS) jsou skrytá nápadná zbarvení u jinak kryptické kořisti, která jsou odhalena při setkání s predátorem. Zahrnují deimatické signály (DS) a flash signály (FS). DS se uplatňují během přímého ohrožení kořisti predátorem, zpravidla až po odhalení predátorem. Jejich pozice v predační sekvenci závisí na druhu kořisti. Často jsou spojené s deimatickým chováním, které posiluje jejich účinnost. K pozdějšímu využití DS v rámci predační sekvence přitom častěji dochází u chráněných druhů, což může vést k urychlení averzivního učení predátorů. U nechráněné kořisti mohou u predátora vyvolat úlekovou reakci, strach, zmatení nebo přetížení smyslů, a tím zpomalit či zastavit jeho útok. FS jsou kořistí odhalovány během úniku před predátorem, většinou hned v počátcích predační sekvence, předtím, než si predátor kořisti všimne. To může u predátora vést k vytvoření mylné představy o vzhledu kořisti, což mu následně ztěžuje její hledání. Při pronásledování mohou FS navíc upoutávat pozornost predátora a snižovat šanci, že si všimne počátku úhybného manévru. Dynamický FS, při kterém dochází ke střídání barev za pohybu, může predátorovi ztěžovat odhad přesné polohy kořisti. Výskyt obou typů SAS často koreluje s velikostí těla kořisti. Účinnost FS je ovlivněna útěkovou vzdáleností kořisti. Účinnosti...Katedra zoologieDepartment of ZoologyPřírodovědecká fakultaFaculty of Scienc
The occurrence and the function of aggressive mimicry in the vertebrates
No full textAggressive mimicry is used by a predator or parasite to deceive a potential prey or host. This bachelor thesis briefly summarizes other similar definitions of this phenomenon a then focuses on the species,especially vertebrates, that are included under this category. The use of the aggressive mimicry by fish of the families Blenniidae, Serranidae, Antennariidae, Labridae a snakes of the families Viperidae, Elapidae a Colubridae is described in more detail. Key worlds: aggressive mimicry, Peckhamian mimicry, caudal luring, toe/pedal luring, lingual lurin
Ecological impacts of New Zealand's invasive outsiders
No full textNový Zéland byl osídlen lidmi jako jedno z posledních míst na zemi. Díky dlouhé izolaci nejen od člověka, ale i od nejbližšího kontinentu se zde vyvinuly unikátní endemické druhy. S příchodem člověka došlo nejen k rozsáhlým změnám v hospodaření s krajinou, ale i k zavlečení nepůvodních druhů, jejichž působení máničivé dopady na původní druhy a krajinu. Řada původních druhů vyhynula a populace dalších klesají navzdory rozsáhlým regulacím zavlečených predátorů a záchranným programům. V zájmu zachování původních druhů se proto Nový Zéland rozhodl do roku 2050 vyhubit tři skupiny nejnebezpečnějších predátorů - kusu liščí, krysy a lasicovité šelmy. Na Novém Zélandu jsou však i další invazní živočichové, kteří nejsou cílem projektu Predator Free New Zealand 2050, i když jejich dopady nejsou zanedbatelné. Pro tyto druhy jsme použili pracovní název "Invazní outsideři". Cílem této práce je prozkoumat podmínky, které formovaly charakter zdejší bioty, a především zhodnotit, jaké dopady mají invazní outsideři na přírodu Nového Zélandu, a zda by nebylo vhodné je zahrnout i do cílů velkého eradikačního projektu. Práce se zaměřuje na vybrané druhy suchozemských savců - ježky, kočky, kopytníky, klokany a myši.New Zealand was settled by humans as one of the last places on earth. Due to its long isolation not only from humans but also from the nearest continent, unique endemic species have evolved here. After the arrival of humans, extensive changes in land use occurred, along with the introduction of non-native species which have had devastating impacts on native species and the landscape. Many native species have become extinct and populations of others are declining despite extensive regulation of introduced predators and rescue programmes. In order to conserve native species, New Zealand has therefore decided to eradicate by 2050 the three most dangerous predator groups - brushtail possum, rats and mustelids. However, there are other invasive animals in New Zealand that are not included in Predator Free New Zealand 2050, although their impacts are not insignificant. We refer to these species as invasive outsiders. The aim of this thesis is to explore the conditions that have shaped the nature of the local biota, and in particular to assess the impacts of invasive outsiders on New Zealand's biota and whether it would be appropriate to include them among the target species of a major eradication project. The thesis focuses on selected terrestrial mammal species - hedgehogs, cats, ungulates, kangaroos...Katedra ekologieDepartment of EcologyFaculty of SciencePřírodovědecká fakult
Citizen science and its application in rodent research
No full textThis bachelor thesis deals with the use of citizen science in rodent research. The aim is to evaluate the potential of this approach for data collection and contribution to biodiversity conservation. The thesis summarizes the theoretical foundations of citizen science, its historical development, and approaches to public involvement. It further analyzes specific examples of projects from different countries. It also focuses on the methods and technologies used, such as camera traps, mobile applications, and acoustic monitoring. Special attention is paid to projects focused on rodents, including monitoring their occurrence and changes in distribution, monitoring invasive species, and opportunities for student involvement in research. The results show that with appropriate project design and thorough training of volunteers, citizen science can provide data comparable to professional research while contributing to environmental education for the public
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
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