37 research outputs found

    Evidence for covert attention switching from eye-movements. Reply to commentaries on Liechty et al., 2003

    Full text link
    We argue that our research objectives in Liechty, Pieters, and Wedel (2003) are to provide generalizable insights into covert visual attention to complex, multimodal stimuli in their natural context, through inverse inference from eye-movement data. We discuss the most important issues raised by Feng (2003) and Reichle and Nelson (2003), in particular the task definition, inclusion of ad features, object-based versus space-based attention and the evidence for the where and what streams.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45760/1/11336_2005_Article_BF02295611.pd

    Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

    Get PDF
    Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

    Random effects diagonal metric multidimensional scaling models

    Full text link
    By assuming a distribution for the subject weights in a diagonal metric (INDSCAL) multidimensional scaling model, the subject weights become random effects. Including random effects in multidimensional scaling models offers several advantages over traditional diagonal metric models such as those fitted by the INDSCAL, ALSCAL, and other multidimensional scaling programs. Unlike traditional models, the number of parameters does not increase with the number of subjects, and, because the distribution of the subject weights is modeled, the construction of linear models of the subject weights and the testing of those models is immediate. Here we define a random effects diagonal metric multidimensional scaling model, give computational algorithms, describe our experiences with these algorithms, and provide an example illustrating the use of the model and algorithms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45758/1/11336_2005_Article_BF02295730.pd

    A monument of inefficiency: The presumed course of the recurrent laryngeal nerve in sauropod dinosaurs

    No full text
    The recurrent laryngeal nerve is an often cited example of “unintelligent design” in biology, especially in the giraffe. The nerve appears early in embryonic development, before the pharyngeal and aortic arches are separated by the development of the neck. The recurrent course of the nerve from the brain, around the great vessels, to the larynx, is shared by all extant tetrapods. Therefore we may infer that the recurrent laryngeal nerve was present in extinct tetrapods, had the same developmental origin, and followed the same course. The longest−necked animals of all time were the extinct sauropod dinosaurs, some of which had necks 14 meters long. In these animals, the neurons that comprised the recurrent laryngeal nerve were at least 28 meters long. Still longer neurons may have spanned the distance from the end of the tail to the brainstem, as in all extant vertebrates. In the longest sauropods these neurons may have been 40–50 meters long, probably the longest cells in the history of life

    The early evolution of postcranial skeletal pneumaticity in sauropodomorph dinosaurs

    No full text
    Postcranial skeletal pneumaticity (PSP) is present in a range of basal sauropodomorphs spanning the basal sauropodomorph–sauropod transition. We describe the PSP of five taxa, Plateosaurus engelhardti, Eucnemesaurus fortis, Aardonyx celestae, Antetonitrus ingenipes, and an unnamed basal sauropod from Spion Kop, South Africa (hereafter referred to as the Spion Kop sauropod). The PSP of Plateosaurus is apparently sporadic in its occurrence and has only been observed in very few specimens, in which it is of very limited extent, affecting only the posterior cervical vertebrae and possibly the mid dorsals in one specimen. The PSP of Eucnemesaurus, Aardonyx, Antetonitrus, and the Spion Kop sauropod consists of subfossae (fossa−within−fossa structures) that excavate the vertices of the posterior infradiapophyseal fossae of the posterior dorsal vertebrae. These subfossae range from simple shallow depressions (Eucnemesaurus) to deep, steepsided, internally subdivided and asymmetrically developed chambers (Antetonitrus). The middle and anterior dorsal vertebrae of these taxa lack PSP, demonstrating that abdominal air sacs were the source of the invasive diverticula. The presence of pneumatic features within the infradiapophyseal fossae suggest that the homologous fossae of more basal saurischians and dinosauriforms were receptacles that housed pneumatic diverticula. We suggest that it is probable that rigid non−compliant lungs ventilated by compliant posterior air sacs evolved prior to the origination of Dinosauria

    Head and neck posture in sauropod dinosaurs inferred from extant animals

    No full text
    The neck posture of sauropod dinosaurs has long been controversial. Recent reconstructions position the cervical vertebrae and skull in an “osteological neutral pose” (ONP), the best fit arrived at by articulating the vertebrae with the zygapophyses in maximum contact. This approach in isolation suggests that most or all sauropods held their necks horizontally. However, a substantial literature on extant amniotes (mammals, turtles, squamates, crocodilians and birds) shows that living animals do not habitually maintain their necks in ONP. Instead, the neck is maximally extended and the head is maximally flexed, so that the mid−cervical region is near vertical. Unless sauropods behaved differently from all extant amniote groups, they must have habitually held their necks extended and their heads flexed. The life orientation of the heads of sauropods has been inferred from the inclination of the semi−circular canals. However, extant animals show wide variation in inclination of the “horizontal” semi−circular canal: the orientation of this structure is not tightly constrained and can give only a general idea of the life posture of extinct animals’ heads

    Vertebral pneumatic structures in the Early Cretaceous sauropod dinosaur Pilmatueia faundezi from northwestern Patagonia, Argentina

    No full text
    One of the diagnostic characters of dicraeosaurid sauropods is a reduction of pneumatization of dorsal and caudal vertebrae relative to their Flagellicaudata sister taxon, Diplodocidae. Here, we analyse pneumatic structures in the dicraeosaurid sauropod Pilmatueia faundezi, compare them to those of diplodocoids and report the first record of camerate chambers in a dicraeosaurid. The pneumatic structures are in a posterior cervical centrum (MLL-Pv-002) and consist of lateral pneumatic fossae on the centrum that communicate internally with large camerae. By contrast, Pilmatueia's dorsal and caudal vertebrae (MLL-Pv-005-016) lack pneumatic fossae on the centra, which is consistent with the previously reported reduced pneumaticity in dicraeosaurids. Nevertheless, the base of the neural arch and possibly the base of the bifid neural spines of a posterior dorsal vertebra (MLL-Pv-005) show pneumatic internal chambers. The pneumatic features of the Pilmatueia cervical centrum and dorsal neural arch we describe indicate that the degree of pneumatization is variable within dicraeosaurids.Fil: Windholz, Guillermo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; ArgentinaFil: Coria, Rodolfo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; ArgentinaFil: Zurriaguz, Virginia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle; Argentin

    3D Mean-Shift Tracking and Recognition of Working Actions

    No full text
    Hahn M, Quronfuleh F, Wöhler C, Kummert F. 3D Mean-Shift Tracking and Recognition of Working Actions. In: Int. Workshop on Human Behaviour Understanding, in cunjunction with ICPR 2010. Istanbul, Turkey: Springer Berlin Heidelberg; 2010

    Dinosaurs and the Cretaceous Terrestrial Revolution

    No full text
    The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125–80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR
    corecore