889 research outputs found
Emilio Ravignani: su tesis doctoral y sus primeros pasos en la práctica de la investigación histórica
No full textFil: Buchbinder, Pablo. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Buenos Aires, ArgentinaFil: Buchbinder, Pablo. CONICET - Universidad de Buenos Aires. Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. Buenos Aires, ArgentinaEstudio preliminar que acompaña la edición electrónica de la tesis del Dr. Emilio Ravignani "Las finanzas argentinas desde 1810 a 1829" publicada por el Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. \nCorresponde al número 1 de la serie Las Tesis del Ravignani
Las finanzas argentinas desde 1810 a 1829
No full textFil: Ravignani, Emilio. Universidad de Buenos Aires. Facultad de Derecho y Ciencias Sociales. Buenos Aires, ArgentinaCon la presentación de Jorge Gelman y estudios preliminares de: María Inés Schroeder, Sandra Sauro, Pablo Buchbinder, y Alejandro CattaruzzaDoctor en Jurisprudenci
Producción y defensa de la Tesis Doctoral de Emilio Ravignani : una ficha técnica
No full textFil: Sauro, Sandra. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Buenos Aires, ArgentinaFil: Sauro, Sandra. CONICET - Universidad de Buenos Aires. Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. Buenos Aires, ArgentinaEstudio preliminar que acompaña la edición electrónica de la tesis del Dr. Emilio Ravignani "Las finanzas argentinas desde 1810 a 1829" publicada por el Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. \nCorresponde al número 1 de la serie Las Tesis del Ravignani
Tesis recuperada o tesis para el olvido. La tesis doctoral de Emilio Ravignani sobre los orígenes de las finanzas argentinas
No full textFil: Schroeder, María Inés. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Buenos Aires, ArgentinaFil: Schroeder, María Inés. CONICET - Universidad de Buenos Aires. Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. Buenos Aires, ArgentinaEstudio preliminar que acompaña la edición electrónica de la tesis del Dr. Emilio Ravignani "Las finanzas argentinas desde 1810 a 1829" publicada por el Instituto de Historia Argentina y Americana Dr. Emilio Ravignani. \nCorresponde al número 1 de la serie Las Tesis del Ravignani
The paradox of learned song in a semi-solitary mammal
No full textLearning can occur via trial and error; however, learning from conspecifics is faster and more efficient. Social animals can easily learn from conspecifics, but how do less social species learn? In particular, birds provide astonishing examples of social learn- ing of vocalizations, while vocal learning from conspecifics is much less understood in mammals. We present a hypothesis aimed at solving an apparent paradox: how can harbor seals (Phoca vitulina) learn their song when their whole lives are marked by loose conspecific social contact? Harbor seal pups are raised individually by their mostly silent mothers. Pups' first few weeks of life show developed vocal plasticity; these weeks are followed by relatively silent years until sexually mature individuals start singing. How can this rather solitary life lead to a learned song? Why do pups display vocal plasticity at a few weeks of age, when this is apparently not needed? Our hypothesis addresses these questions and tries to explain how vocal learning fits into the natural history of harbor seals, and potentially other less social mammals. We suggest that harbor seals learn during a sensitive period within puppyhood, where they are exposed to adult males singing. In particular, we hypothesize that, to make this learning possible, the following happens concurrently: (1) mothers give birth right before male singing starts, (2) pups enter a sensitive learning phase around weaning time, which (3) coincides with their foraging expeditions at sea which, (4) in turn, co- incide with the peak singing activity of adult males. In other words, harbor seals show vocal learning as pups so they can acquire elements of their future song from adults, and solitary adults can sing because they have acquired these elements as pups. We review the available evidence and suggest that pups learn adult vocalizations because they are born exactly at the right time to eavesdrop on singing adults. We conclude by advancing empirical predictions and testable hypotheses for future work
Las finanzas argentinas desde 1810 a 1829
No full textFil: Ravignani, Emilio. Universidad de Buenos Aires. Facultad de Derecho y Ciencias Sociales. Buenos Aires, ArgentinaVersión facsimilar de la tesis mecanografiada.\nIncluye tapa y páginas 304-305 del Libro de Actas de defensa de tesis. Tomo I (1879-1942)Doctor en Jurisprudenci
Vocal usage learning and vocal comprehension learning in harbor seals
No full textBackground: Which mammals show vocal learning abilities, e.g., can learn new sounds, or learn to use sounds in new contexts? Vocal usage and comprehension learning are submodules of vocal learning. Specifically, vocal usage learning is the ability to learn to use a vocalization in a new context; vocal comprehension learning is the ability to comprehend a vocalization in a new context. Among mammals, harbor seals (Phoca vitulina) are good candidates to investigate vocal learning. Here, we test whether harbor seals are capable of vocal usage and comprehension learning. Results: We trained two harbor seals to (i) switch contexts from a visual to an auditory cue. In particular, the seals first produced two vocalization types in response to two hand signs; they then transitioned to producing these two vocalization types upon the presentation of two distinct sets of playbacks of their own vocalizations. We then (ii) exposed the seals to a combination of trained and novel vocalization stimuli. In a final experiment, (iii) we broadcasted only novel vocalizations of the two vocalization types to test whether seals could generalize from the trained set of stimuli to only novel items of a given vocal category. Both seals learned all tasks and took ≤ 16 sessions to succeed across all experiments. In particular, the seals showed contextual learning through switching the context from former visual to novel auditory cues, vocal matching and generalization. Finally, by responding to the played-back vocalizations with distinct vocalizations, the animals showed vocal comprehension learning. Conclusions: It has been suggested that harbor seals are vocal learners; however, to date, these observations had not been confirmed in controlled experiments. Here, through three experiments, we could show that harbor seals are capable of both vocal usage and comprehension learning
Chorusing, synchrony and the evolutionary functions of rhythm
No full textA central goal of biomusicology is to understand the biological basis of human musicality. One approach to this problem has been to compare core components of human musicality (relative pitch perception, entrainment, etc.) with similar capacities in other animal species. Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony), we argue for the central importance of temporal properties, and propose that this domain is ripe for further comparative research. Second, whereas most rhythm research in non-human animals has examined animal timing in isolation, we consider how chorusing dynamics can shape individual timing, as in human music and dance, making group behavior key to understand the adaptive functions of rhythm. To illustrate the interdependence between individual and chorusing dynamics, we present a computational model of chorusing agents relating individual call timing with synchronous group behavior. Third, we distinguish and clarify mechanistic and functional explanations of rhythmic phenomena, often conflated in the literature, arguing that this distinction is key for understanding the evolution of musicality. Fourth, we expand biomusicological discussions beyond the species typically considered, providing an overview of chorusing and rhythmic behavior across a broad range of taxa (orthopterans, fireflies, frogs, birds, and primates). Finally, we propose an "Evolving Signal Timing" hypothesis, suggesting that similarities between timing abilities in biological species will be based on comparable chorusing behaviors. We conclude that the comparative study of chorusing species can provide important insights into the adaptive function(s) of rhythmic behavior in our "proto-musical" primate ancestors, and thus inform our understanding of the biology and evolution of rhythm in human music and language
Visual timing abilities of a harbour seal (Phoca vitulina) and a South African fur seal (Arctocephalus pusillus pusillus) for sub- and supra-second time intervals
No full textTiming is an essential parameter influencing many behaviours. A previous study demonstrated a high sensitivity of a phocid, the harbour seal (Phoca vitulina), in discriminating time intervals. In the present study, we compared the harbour seal’s timing abilities with the timing abilities of an otariid, the South African fur seal (Arctocephalus pusillus pusillus). This comparison seemed essential as phocids and otariids differ in many respects and might, thus, also differ regarding their timing abilities. We determined time difference thresholds for sub- and suprasecond time intervals marked by a white circle on a black background displayed for a specific time interval on a monitor using a staircase method. Contrary to our expectation, the timing abilities of the fur seal and the harbour seal were comparable. Over a broad range of time intervals, 0.8–7 s in the fur seal and 0.8–30 s in the harbour seal, the difference thresholds followed Weber’s law. In this range, both animals could discriminate time intervals differing only by 12 % and 14 % on average. Timing might, thus be a fundamental cue for pinnipeds in general to be used in various contexts, thereby complementing information provided by classical sensory systems. Future studies will help to clarify if timing is indeed involved in foraging decisions or the estimation of travel speed or distance
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