1,721,115 research outputs found
Pigeons with ablated pyriform cortex home from familiar but not from unfamiliar sites
No full textHoming behavior was tested in pigeons
(Columba livia) after removing a portion of the ventrolateral
telencephalon, which receives extensive projections from the
olfactory bulb and is comparable with the mammalian pyriform
cortex. Ablated pigeons show unaffected cardiac responses
to odorous stimuli but altered homing behavior. After
the operation, the birds were trained by repeated flock releases
along with control birds from a site 40 km from the loft. After
being released singly from this familiar site, the ablated birds
turned out to be unaffected by the operation. In releases from
two unfamiliar sites, ablated birds, unlike control birds, were
not homeward oriented and were mostly lost. The ablation of
the pyriform cortex has the same effect on homing behavior as
olfactory deprivation. It can be concluded that the pyriform
cortex plays an important role in the specific mechanisms
linking olfactory inputs with the navigational response
Moon orientation in sandhoppers: effects of lighting treatments on the persistence of orientation ability
No full textLunar orientation in sandhoppers is affected by shifting both the moon phase and daily clock
No full textDomestic dogs display calming signals more frequently towards unfamiliar rather than familiar dogs
No full textRugaas (1997) describes “calming signals” as certain dog behaviors that would allow subjects receiving them to calm, avoiding open aggression. The aim of the current research is to assess whether the display of the so-called “calming signals” differs according to the familiarity of dogs involved in the meeting.
We studied 20 dogs (10 males and 10 females) who met conspecifics within an outdoor fence (5 x 5 m). In all of the encounters dogs were in pairs and off-leash, but both owners were present within the fence and instructed not to interact with the dogs. Subjects showing open aggression to dogs or humans were excluded for ethical reasons.
Each dog met four conspecifics: a female and a male familiar dog, and a female and a male unfamiliar dog. Each 5-minute encounter was videorecorded from two different points and then analyzed to measure the total number of emissions of the signals.
Examined signals were 21 of those suggested by Rugaas (1997): ‘turning head’, ‘looking elsewhere’, ‘half-closing eyes’, ‘turning on other's side or back’, ‘licking nose, freezing’, ‘moving slowly’, ‘play bow’, ‘sitting’, ‘sitting and turning on other's back’, ‘laying down (sternal decubitus)’, ‘yawning’, ‘sniffing the ground or wall’, ‘approaching the other dog curving’, ‘waving low tail’, ‘cowering’, ‘licking the other dog's mouth’, ‘blinking’, ‘smacking’, ‘raising a forelimb’ and ‘low urination’. We could not consider two signals listed by Rugaas (1997): ‘going between’, because dogs were only two in each meeting, and ‘pretending to ignore the other dog exists’, as the assessment may result too subjective.
Analyzing videos, it was found that the total number of signals were more than doubled when the dogs met were unfamiliar (848 vs. 365). This suggests that facing an unknown subject is more challenging and needs clearer communication regarding intentions.
Comparing the display of single behaviors between familiar and unfamiliar dogs, we observed a very similar trend for most behaviors, with a tendency to higher frequencies when dogs did not know each other. In particular, some signals were rarely or not displayed at all in both conditions (‘low urination', ‘blinking’, ‘smacking’, ‘licking others dog's muzzle’, ‘slow movements’, ‘play bow’, ‘sitting’, ‘sitting on other's side or back’, ‘sternal decubitus’, ‘yawning’, ‘curving’, ‘waving low tail’ and ‘raising a forelimb'). Some other signals were displayed nearly twice as often in case of unfamiliar dogs, even if overall frequencies were not high (‘sniffing ground or wall’: 28 vs. 18; ‘turning on other's side or back’: 43 vs. 26; ‘turning head’: 95 vs. 40; ‘licking nose’: 168 vs. 59), but differences were not statistically significant. ‘Looking elsewhere’ (265 vs. 166; χ2 = 21.938; p = 0.0001) and ‘freezing’ (135 vs. 20; χ2 = 24.027; p = 0.0001) were significantly more frequent in encounters between unfamiliar dogs.
In conclusion, intraspecific communication in dogs seems to vary according to familiarity, the difference being more in degree rather than in kind. A higher number of calming signals (especially specific ones, such as ‘looking elsewhere’ and ‘freezing') are displayed when a dog meets an unfamiliar dog
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
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