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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
Interspecific hybridization between the grasshoppers Chorthippus biguttulus and C. brunneus (Acrididae; Gomphocerinae)
Full text linkThe effectiveness of hybridization barriers determines whether two species remain reproductively isolated when their populations come into contact. I investigated acoustic mating signals and associated leg movements responsible for song creation of hybrids between the grasshopper species Chorthippus biguttulus and C. brunneus to study whether and how songs of male hybrids contribute to reproductive isolation between these sympatrically occurring species. Songs of F1, F2 and backcross hybrids were intermediate between those of both parental species in terms phrase number and duration. In contrast, species-specific syllable structure within phrases was largely lost in hybrids and was produced, if at all, in an irregular and imperfect manner. These divergences in inheritance of different song parameters are likely the result of incompatibility of neuronal networks that control stridulatory leg movements in hybrids. It is highly probable that songs of hybrid males are unattractive to females of either parental species because they are intermediate in terms of phrase duration and lack a clear syllable structure. Males of various hybrid types (F1, F2 and backcrosses) are behaviorally sterile because their songs fail to attract mates. In the second chapter I question why two sympatric grasshopper species, Chorthippus biguttulus and C. brunneus (Gomphocerinae) remain distinct species, despite occasional hybridisation between them. Therefore I performed hybridisation experiments and accessed female preferences for song parameters of the pure species and the interspecific F1 hybrids. Females of gomphocerine grasshopper respond to species-specific male calling songs with reply songs. I conducted playback experiments with virgin females using model songs. Two parameters, namely phrase duration and syllable pattern were varied ranging from biguttulus to brunneus- like songs. For C. biguttulus females the syllable pattern of songs is the crucial character, whereas for C. brunneus females the syllable pattern is of minor importance whereas phrase duration is the most important character. In F1 hybrid females I found an interesting twofold inheritance. The F1 females accepted a range of phrase durations from brunneus phrase durations up to the longest phrases tested. The preference for phrase duration may be inherited intermediate. But in preferences for syllable pattern F1 hybrid females clearly behaved like C. biguttulus females. Hence I assume that the preference for syllable patterns is inherited dominantly. Consequently, as calling songs of hybrid males between C. biguttulus and C. brunneus lack a correct syllable structure, females will not choose these males as mating partners. If hybrids between the two species occur in nature females will rather cross back to biguttulus, than to hybrids or brunneus males. Thus the dominant expression of the syllable pattern strengthens the isolating barrier between the two sympatric species and helps to maintain species boundaries despite introgression. Interspecific hybridisation could play a major role in the evolution of novel signals and in the diversification in animals. In the third chapter I investigate whether a gomphocerine grasshopper, C. jutlandica, occurring in West-Jutland, Denmark, could be of hybrid origin between the species C. biguttulus and C. brunneus. It is known that the premating isolation mechanisms between the two species are strong and they occur in sympatry throughout most of their distribution range despite occasional hybridization. I compared songs of males and female preferences of C. jutlandica with those of hybrids between C. biguttulus and C. brunneus reared in the laboratory. F1 hybrids and C. jutlandica were extremely variable in male song parameters as well as in female preferences. Male calling songs of F1 hybrids and C. jutlandica were very similar, but the latter tended to produce more regular syllables. Preferences of C. jutlandica and laboratory hybrid females resembled each other, but C. jutlandica females were less critical concerning syllable pattern. Females of C. jutlandica accepted C. biguttulus, C. jutlandica and F1 hybrid songs, but not songs of C. brunneus. Our results confirm a hybrid origin of C. jutlandica. The C. jutlandica population has more in common with C. biguttulus and is clearly separated from C. brunneus. This population maintains its distinctiveness because C. biguttulus does not occur in West-Jutland.Die zwei europäischen Feldheuschreckenarten Chorthippus biguttulus und C. brunneus kommen in ihrem Verbreitungsgebiet weitestgehend sympatrisch und häufig syntop vor. Sie unterscheiden sich kaum in ihrer äußeren Morphologie, in ihrer Ökologie und in neutralen genetischen Markern. Im Gegensatz dazu produzieren die Männchen beider Arten artspezifische Gesänge und die Weibchen besitzen artspezifische Gesangspräferenzen, was eine effektive prägame Hybridisationsbarriere zur Folge hat. Dennoch werden in der Natur immer wieder Hybride zwischen den beiden Arten gefunden. Dies wirft die Frage auf, weshalb sich die beiden Arten trotz gelegentlicher Hybridisierung nicht vermischen und stattdessen vielfach syntop vorkommen. Um dieser Frage nachzugehen, untersuchte ich Verhaltensmerkmale beider Geschlechter von C. biguttulus, C. brunneus, und der interspezifischen Hybriden. Die akustischen Isolationsmechanismen wurden experimentell außer Kraft gesetzt, so dass Kreuzverpaarungen zwischen den Arten durchführbar waren. Die Gesänge wurden mit einer Positionsapparatur aufgenommen, die das akustische Signal und die Beinbewegungen der beiden Hinterbeine simultan aufzeichnete. Da paarungsbereite Weibchen auf artspezifische Gesänge antworten, ist es möglich, die Präferenzen der Weibchen für bestimmte Gesangsparameter experimentell zu untersuchen. Hierfür verwendete ich einen computergesteuerten Versuchsaufbau, der den Tieren akustische Signale vorspielte und die Antworten der Weibchen mit Hilfe eines Mikrophons registrierte. Im ersten Kapitel der Arbeit analysierte ich die Spontangesänge der Männchen von C. biguttulus, C. brunneus und deren Hybriden. Die Gesänge der Hybridmännchen (F1, F2 Generation und Rückkreuzungen) waren hinsichtlich der Anzahl an Versen pro Gesang und der Versdauern intermediär ausgeprägt. Im Gegensatz dazu war die artspezifische Silbenstruktur der Gesänge der Elternarten weitestgehend verloren gegangen. Gelegentlich in den Hybridgesängen auftretende Silben waren sowohl in ihrer Dauer als auch in ihrer Struktur sehr unregelmäßig. Die Gesänge der Hybridmännchen sind wegen der fehlenden Silbenstruktur für C. biguttulus Weibchen unattraktiv. Da sie über zu lange Verse verfügen, lehnen auch C. brunneus Weibchen Gesänge von Hybriden ab. Im zweiten Kapitel untersuche ich, inwieweit Hybridweibchen und Weibchen der beiden Elternarten gegen die Hybridgesänge selektieren. Dazu wurde den Weibchen künstlich generierte Gesänge vorgespielt, die in Versdauern und Silbenmuster variiert wurden. Für C. biguttulus Weibchen war das Silbenmuster ein entscheidendes Kriterium, während C. brunneus Weibchen allein aufgrund der Versdauer selektierten. Ein überraschendes Ergebnis war, dass die Hybridweibchen ein ähnliches Lautschema wie C. biguttulus Weibchen hatten. Auch für Hybridweibchen musste das Silbenmuster einem biguttulus-Silbenmuster entsprechen. Die Präferenz für Silbenmuster wird offenbar dominant vererbt. Bei der Verwendung von biguttulus-Silbenmustern akzeptierten die Hybridweibchen eine große Bandbreite von recht kurzen bis zu sehr langen Versdauern, was auf eine intermediäre Vererbung dieses Merkmals deutet. Die Ergebnisse zeigen, dass Hybridweibchen die Hybridmännchen nicht als Paarungspartner wählen, sondern eindeutig C. biguttulus Männchen bevorzugen. Die Gesänge von Hybridmännchen werden demnach von keinem Weibchen akzeptiert, weshalb Hybridmännchen verhaltenssteril sind. Dies stellt eine postzygotische Isolationsbarriere dar, die auch bei einer gelegentlichen Hybridisierung zwischen C. biguttulus und C. brunneus in der Natur erhalten bleibt. Im dritten Kapitel wurde C. jutlandica, eine erst kürzlich neu-beschriebene Art aus der C. biguttulus Artengruppe aus Jütland in Dänemark untersucht. Der Vergleich der Gesänge von im Labor erzeugten F1 Hybriden (C. biguttulus x C. brunneus) und C. jutlandica-Männchen zeigte, dass es ich bei der Population von C. jutlandica um Hybride zwischen C. biguttulus und C. brunneus handelt. Die Gesänge von C. jutlandica Männchen und F1 Hybriden waren sowohl in den Vers- als auch in den Silbendauern sehr ähnlich. Allerdings tendierten C. jutlandica Männchen dazu regelmäßigere Silben zu bilden als F1-Hybride. Auch in den Gesangspräferenzen von C. jutlandica und der Hybridweibchen zeigten sich Übereinstimmungen, vor allem in der Bevorzugung von strukturierten Gesängen. Chorthippus jutlandica Weibchen antworteten auf Gesänge von C. biguttulus, C. jutlandica und F1 Hybridmännchen jedoch nie auf Gesänge von C. brunneus. Diese Ergebnisse legen nahe, dass eine isolierte Population C. biguttulus in West-Jütland lokal mit C. brunneus hybridisierte. Da C. jutlandica Weibchen C. brunneus Männchen ablehnen, können C. jutlandica und C. brunneus sympatrisch vorkommen. Sollte C. biguttulus sich nach West-Jütland ausbreiten, so ist zu erwarten, dass es zumindest aufgrund der Gesänge und Gesangspräferenzen keine effektiven Hybridisationsbarrieren zwischen C. biguttulus und C. jutlandica gibt und es somit zur Vermischung beider Formen kommen wird
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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