Urban Policy in the Carter Administration

Scans literature on the Carter administration's review of urban policy, its recommendations, and the history of spatial distribution analysis of federal outlays. Explores lessons for the Obama administration's review of metropolitan revitalization policy

Campaign of aerodynamic measurements in a wind tunnel

2017/201

A potential record of a procolophonid parareptile from the Triassic of the Iberian Peninsula

Cranial and postcranial remains from the Middle Triassic of the Northeastern part of the Iberian Peninsula are reported and tentatively assigned to Procolophonidae. The finding is the first occurrence of a procolophonid parareptile in the Iberian Peninsula, representing the southernmost record of the group in Europe. The fossilbearing locality is dated as Anisian (Middle Triassic) and includes three tooth-bearing bones, two cranial bone fragments and one interclavicle. The mandible described herein includes nine teeth. No cusps or complete crowns are preserved, but sections of the teeth are available. The three anterior teeth progressively decrease in size from front to back, whereas the teeth from the fourth to the eighth position present the opposite trend. The last tooth (the ninth) is clearly reduced in comparison to the previous ones. A close relationship with Anomoiodon-Kapes is suggested, however, more material is required in order to assess the exact taxonomical determination of the Iberian remains. This finding is expected to shed some light on the geographical distribution of procolophonines

Determining the constitutive parameters of the human femoral vein in specific patients

This study suggests a method for computing the constitutive model for veins in vivo from clinically registered ultrasound images. The vein is modelled as a hyperelastic, incompressible, thin-walled cylinder and the membrane stresses are computed using strain energy. The material parameters are determined by tuning the membrane stress to the stress obtained by enforcing global equilibrium. In addition to the mechanical model, the study also suggests a preconditioning of the pressure-radius signal. The preconditioning computes an average pressure-radius cycle from all consecutive cycles in the registration and removes, or reduces undesirable disturbances. In order to overcome this problem, an approach is proposed that allows constitutive equations to be determined from clinical data by means of reasonable assumptions regarding in situ configurations and stress states of vein walls. The approach is based on a two-dimensional Fung-type stored-energy function that captures the characteristic nonlinear and anisotropic responses of vein

Emergence of Zipf's Law in the Evolution of Communication

Zipf's law seems to be ubiquitous in human languages and appears to be a universal property of complex communicating systems. Following the early proposal made by Zipf concerning the presence of a tension between the efforts of speaker and hearer in a communication system, we introduce evolution by means of a variational approach to the problem based on Kullback's Minimum Discrimination of Information Principle. Therefore, using a formalism fully embedded in the framework of information theory, we demonstrate that Zipf's law is the only expected outcome of an evolving, communicative system under a rigorous definition of the communicative tension described by Zipf.Comment: 7 pages, 2 figure

Restoration of deteriorated text sections in ancient document images using atri-level semi-adaptive thresholding technique

The proposed research aims to restore deteriorated text sections that are affected by stain markings, ink seepages and document ageing in ancient document photographs, as these challenges confront document enhancement. A tri-level semi-adaptive thresholding technique is developed in this paper to overcome the issues. The primary focus, however, is on removing deteriorations that obscure text sections. The proposed algorithm includes three levels of degradation removal as well as pre- and post-enhancement processes. In level-wise degradation removal, a global thresholding approach is used, whereas, pseudo-colouring uses local thresholding procedures. Experiments on palm leaf and DIBCO document photos reveal a decent performance in removing ink/oil stains whilst retaining obscured text sections. In DIBCO and palm leaf datasets, our system also showed its efficacy in removing common deteriorations such as uneven illumination, show throughs, discolouration and writing marks. The proposed technique directly correlates to other thresholding-based benchmark techniques producing average F-measure and precision of 65.73 and 93% towards DIBCO datasets and 55.24 and 94% towards palm leaf datasets. Subjective analysis shows the robustness of proposed model towards the removal of stains degradations with a qualitative score of 3 towards 45% of samples indicating degradation removal with fairly readable text

Extending the footprint record of Pareiasauromorpha to the Cisuralian : earlier appearance and wider palaeobiogeography of the group

Pareiasauromorpha is one of the most important tetrapod groups of the Permian. Skeletal evidence suggests a late Kungurian origin in North America, whereas the majority of occurrences come from the Guadalupian and Lopingian of South Africa and Russia. However, Pareiasauromorpha footprints include the ichnogenus Pachypes, which is unknown from strata older than late Guadalupian. A revision of several Pachypes-like footprints from the Cisuralian-Guadalupian of Europe and North America confirm the occurrence of this ichnogenus and of the ichnospecies Pachypes ollieri comb. nov. beginning in the Artinskian. This is the earliest known occurrence of Pachypes and it coincides with the Artinskian reptile radiation. Based on a synapomorphy-based track-trackmaker correlation, P. ollieri can be attributed to nycteroleter pareiasauromorphs such as Macroleter. Therefore, the earliest occurrences of pareiasauromorph footprints precede by at least 10 myr the earliest occurrence of this group in the skeletal record. Moreover, the palaeobiogeography of the group is extended to the Cisuralian and Guadalupian of western Europe

3-D Modelling of Megaloolithid Clutches: Insights about Nest Construction and Dinosaur Behaviour

BACKGROUND: Megaloolithid eggs have long been associated with sauropod dinosaurs. Despite their extensive and worldwide fossil record, interpretations of egg size and shape, clutch morphology, and incubation strategy vary. The Pinyes locality in the Upper Cretaceous Tremp Formation in the southern Pyrenees, Catalonia provides new information for addressing these issues. Nine horizons containing Megaloolithus siruguei clutches are exposed near the village of Coll de Nargó. Tectonic deformation in the study area strongly influenced egg size and shape, which could potentially lead to misinterpretation of reproductive biology if 2D and 3D maps are not corrected for bed dip that results from tectonism. METHODOLOGY/FINDINGS: Detailed taphonomic study and three-dimensional modelling of fossil eggs show that intact M. siruguei clutches contained 20-28 eggs, which is substantially larger than commonly reported from Europe and India. Linear and grouped eggs occur in three superimposed levels and form an asymmetric, elongate, bowl-shaped profile in lateral view. Computed tomography data support previous interpretations that the eggs hatched within the substrate. Megaloolithid clutch sizes reported from other European and Indian localities are typically less than 15 eggs; however, these clutches often include linear or grouped eggs that resemble those of the larger Pinyes clutches and may reflect preservation of incomplete clutches. CONCLUSIONS/SIGNIFICANCE: We propose that 25 eggs represent a typical megaloolithid clutch size and smaller egg clusters that display linear or grouped egg arrangements reported at Pinyes and other localities may represent eroded remnants of larger clutches. The similarity of megaloolithid clutch morphology from localities worldwide strongly suggests common reproductive behaviour. The distinct clutch geometry at Pinyes and other localities likely resulted from the asymmetrical, inclined, and laterally compressed titanosaur pes unguals of the female, using the hind foot for scratch-digging during nest excavation

A new species of Allodaposuchus (Eusuchia, Crocodylia) from the Maastrichtian (Late Cretaceous) of Spain : phylogenetic and paleobiological implications

Background. The Late Cretaceous is a keystone period to understand the origin and early radiation of Crocodylia, the group containing all extant lineages of crocodilians. Among the taxa described from the latest Cretaceous of Europe, the genus Allodaposuchus is one of the most common but also one of the most controversial. However, because of its fragmentary record, several issues regarding its phylogenetic emplacement and its ecology remain unsolved or unknown. The discovery of a single specimen attributed to Allodaposuchus, represented by both cranial and postcranial remains, from the Casa Fabà site (Tremp Basin, NE Spain) in the lower red unit of the Tremp Fm. (early Maastrichtian, Late Cretaceous) offers a unique opportunity to deepen in the phylogenetic relationships of the group and its ecological features. Methods. The specimen is described in detail, and CT scan of the skull is performed in order to study the endocranial morphology as well as paratympanic sinuses configuration. In addition, myological and phylogenetic analyses are also carried out on the specimen for to shed light in ecological and phylogenetic issues, respectively. Results. The specimen described herein represents a new species, Allodaposuchus hulki sp. nov., closely related to the Romanian A. precedens. The CT scan of the skull revealed an unexpected paratympanic sinuses configuration. Allosaposuchus hulki exhibits an "anterodorsal tympanic sinus" not observed in any other extant or extinct crocodilian. The caudal tympanic recesses are extremely enlarged, and the expanded quadratic sinus seems to be connected to the middle-ear channel. Phylogenetic analyses confirm the emplacement of the informal taxonomic group 'Allodaposuchia' at the base of Crocodylia, being considered the sister group of Borealosuchus and Planocraniidae. Discussion. Although this is a preliminary hypothesis, the unique paratympanic configuration displayed by A. hulki suggests that it could possess a high-specialized auditory system. Further, the large cranial cavities could help to reduce the weight of the cranium. Concerning the postcranial skeleton, Allodaposuchus hulki shows massive and robust vertebrae and forelimb bones, suggesting it could have a bulky body. The myological study performed on the anterior limb elements supports this interpretation. In addition, several bone and muscular features seem to point at a semi-erected position of the forelimbs during terrestrial locomotion. Taking all the above results into consideration, it seems plausible to suggest that A. hulki could conduct large incursions out of the water and have a semi-terrestrial lifestyle

On the origin of ambiguity in efficient communication

This article studies the emergence of ambiguity in communication through the concept of logical irreversibility and within the framework of Shannon's information theory. This leads us to a precise and general expression of the intuition behind Zipf's vocabulary balance in terms of a symmetry equation between the complexities of the coding and the decoding processes that imposes an unavoidable amount of logical uncertainty in natural communication. Accordingly, the emergence of irreversible computations is required if the complexities of the coding and the decoding processes are balanced in a symmetric scenario, which means that the emergence of ambiguous codes is a necessary condition for natural communication to succeed.Comment: 28 pages, 2 figure