No abstract

No abstract

, have revealed important fossil accumulations attributed to the Upper Pleistocene-Holocene. Recently, the first fossil records were recovered from the Tacho de Ouro cave, which are assigned to Tayassu pecari, Cervidae indet., Odocoileus virginianus, Mazama sp., Palaeolama major, Tapirus sp., Coendou sp. and Catonyx cuvieri. The presence of extinct taxa suggests that this fossil assemblage maybe attributed to the late Pleistocene-Holocene interval. Information on the recognized habitats for the species found in the cave indicates an environment affected by climatic variations in this interval, corroborating with the hypothesis of non-contemporaneity of the species. The presence of O. virginianus in Tacho de Ouro cave represents the southmost occurrence of the species in Brazil. The taphonomical analysis indicates that the animals probably perished externally to the cave and then were carried into the cave by a low-energy hydraulic flow, being quickly buried in contact with the vadose level of the cave. Trace fossils observed in some specimens are associated with the predation or scavenging by carnivores (Fodinichnia).

Birds and pterosaurs have pneumatic bones, a feature likely related to their flight capabilities but whose evolution and origin is still poorly understood. Pneumatic foramina are present on the external surface of the bone and are reliable indicators of post-cranial skeletal pneumatization present in Pterosauria, Eusauropoda, and Neotheropoda. Here, we carried out a qualitative analysis of the position, size and number of pneumatic foramina of the cervical and thoracic/dorsal vertebrae of pterosaurs and birds, as they have the potential to challenge hypotheses about the emergence and evolution of the respiratory trait in these groups. We also discussed differences between pneumatic and vascular foramina for identification purposes. Besides phylogenetic representativeness, the pterosaur taxonomic sampling considered the preservation of specimens and, for birds, their life habit, as this relates to the level of pneumatization. Pneumatic foramina on the lateral faces of the centrum of the mid-cervical vertebrae of pterosaurs and birds differ in position and size, and those adjacent to the neural canal additionally differ in number. The avian posterior cervical vertebrae show a higher number of pneumatic foramina in comparison to their mid-cervicals, while the opposite is true for pterosaurs, suggesting differences in the cervical air sac of these clades. Pneumatic foramina were found at the base of the transverse processes of the notarial vertebrae of birds, while they were absent from some of the pterosaurs analyzed here, revealing the presence of a pneumatic hiatus in the vertebral column that might be explained due to the distance of this structure to the cervical air sac. These findings indicate that, although the overall skeletal pneumatization of pterosaurs and birds present deep homologies, some pneumatic features occurred convergently because variation in the number of pneumatic foramina along the vertebral column is related to the position of the air sacs in pterosaurs and birds and/or the habit of each species. There is an evident reduction of the pneumatic foramina in birds that have aquatic foraging and an increase in the ones which perform static soaring. Although we did not find any external anatomical difference between pneumatic and vascular foramina, we observed that vascular foramina occur at specific sites and thus identification on the basis of location is reliable.

Research on the postcranial skeletal pneumaticity in pterosaurs is common in the literature, but most studies present only qualitative assessments. When quantitative, they are done on isolated bones. Here, we estimate the Air Space Proportion (ASP) obtained from micro-CT scans of the sequence from the sixth cervical to the fourth dorsal vertebra of an anhanguerine pterosaur to understand how pneumaticity is distributed in these bones. Pneumatisation of the vertebrae varied between 68 and 72% of their total volume. The neural arch showed higher ASP in all vertebrae. Anhanguerine vertebral ASP was generally higher than in sauropod vertebrae but lower than in most extant birds. The ASP observed here is lower than that calculated for the appendicular skeleton of other anhanguerian pterosaurs, indicating the potential existence of variation between axial and appendicular pneumatisation. The results point to a pattern in the distribution of the air space, which shows an increase in the area occupied by the trabecular bone in the craniocaudal direction of the vertebral series and, in each vertebra, an increase of the thickness of the trabeculae in the zygapophyses. This indicates that the distribution of pneumatic diverticula in anhanguerine vertebrae may not be associated with stochastic patterns.

This paper focuses on the simulation of heterogeneous systems, in terms of hardware and software, that contain thousands of various Embedded Control Units (ECUs) which communicate with each other throughout a network. Designers need to simulate ECU interactions to execute and validate the whole system since hardware and software have strong mutual dependencies. We propose a modeling approach based on a Hardware Abstraction Layer (HAL) interface, which is the main programming constraint, to achieve fast simulations. Our simulator allows to perform early simulation of heterogeneous ECUs in a few seconds and scales up to thousands ECUs. Experimental results show that the simulation speed and the scalability are very similar to state of the art Wireless Sensor Network (WSN) simulators but our approach implies lesser constraints about programming language, and simulation kernel.

No abstract

No abstract