A temnospondyl trackway from the early mesozoic of Western gondwana and its implications for Basal tetrapod locomotion

BACKGROUND: Temnospondyls are one of the earliest radiations of limbed vertebrates. Skeletal remains of more than 190 genera have been identified from late Paleozoic and early Mesozoic rocks. Paleozoic temnospondyls comprise mainly small to medium sized forms of diverse habits ranging from fully aquatic to fully terrestrial. Accordingly, their ichnological record includes tracks described from many Laurasian localities. Mesozoic temnospondyls, in contrast, include mostly medium to large aquatic or semi-aquatic forms. Exceedingly few fossil tracks or trackways have been attributed to Mesozoic temnospondyls, and as a consequence very little is known of their locomotor capabilities on land. METHODOLOGY/PRINCIPAL FINDINGS: We report a ca. 200 Ma trackway, Episcopopus ventrosus , from Lesotho, southern Africa that was made by a 3.5 m-long animal. This relatively long trackway records the trackmaker dragging its body along a wet substrate using only the tips of its digits, which in the manus left characteristic drag marks. Based on detailed mapping, casting, and laser scanning of the best-preserved part of the trackway, we identified synapomorphies (e.g., tetradactyl manus, pentadactyl pes) and symplesiomorphies (e.g., absence of claws) in the Episcopopus trackway that indicate a temnospondyl trackmaker. Conclusions/Significance Our analysis shows that the Episcopopus trackmaker progressed with a sprawling posture, using a lateral-sequence walk. Its forelimbs were the major propulsive elements and there was little lateral bending of the trunk. We suggest this locomotor style, which differs dramatically from the hindlimb-driven locomotion of salamanders and other extant terrestrial tetrapods can be explained by the forwardly shifted center of mass resulting from the relatively large heads and heavily pectoral girdles of temnospondyls

GEOCONTEXT AND CHCONTEXT GEOGRAPHIC INFORMATION IN CULTURAL HERITAGE

Internet presence and applications are central for modern museums and cultural institutions. Even more it is important to facilitate and standardize the user experience in order to create a standard quality level and, for the institutions, it is important to simplify configuration operations bound to the creation of the visualized elements and the explorations of the spaces. This demo covers both the technologies underneath the GeoContext tool and the CHContext visualization generator as well as the possible targets and applications. The final elements will cover possible enhancements already in the works

Explaining the increasing inequality in life expectancy across income groups

We present a novel life-cycle model, grounded in demographic principles, to examine the influence of medical progress, technological progress, and the reduction in age-independent mortality on the rise in life expectancy across socioeconomic groups. Our findings indicate that the expanding disparity in life expectancy across income groups, as well as the growing income inequality among educational groups in the US, can be attributed to a selection process that changes the composition of the initial characteristics (learning ability, schooling effort, and health frailty) of the income groups. This selection process is triggered by the rising income and medical advancements that emerged with the cardiovascular revolution in the 1970

Locomotor kinematics of the manus and pes in dinocephalian therapsids reconstructed from three-dimensional morphology of footprints from Gansfontein, South Africa

The Gansfontein paleosurface from the Late PermianAbrahamskraal Formation (Beaufort Group, TapinocephalusAssemblage Zone) near Fraserburg, South Africa, preserves several vertebratetrackways. Among the best-preserved trackways is a series of several footprintsthat have been attributed to a single dinocephalian therapsid walking acrossthe surface. This attribution is based on both the large size of the footprints(25 cm in breadth), and the reduction of digit I in the manus and pes. However,a curious feature of this trackway is that, in contrast to the straight digitsindicated by skeletal specimens of dinocephalians, the digit impressions from theprints are curved so that their tips point medially. To test hypotheses aboutthe locomotor kinematics of the dinocephalian manus and pes that produced thesecurved-digit prints, we constructed contour maps that depicted how the depth ofan impression varied within individual prints. In our initial analysis, we constructedthe maps by pouring milk into the prints in successive increments of 2 mm inheight, and tracing the perimeters of filled areas on translucent paper fixedto the paleosurface by tape. We have also used surface scanners to generatedepth profiles with finer scale resolution. These analyses indicated that thedistal tips of digit impressions are among the shallowest portions of theprints, a pattern consistent with outward rotation of the hand and foot duringstance. In addition, heel impressions are lacking in the prints, indicatingthat the animal that made them may have used digitigrade foot posture. Spacing betweenleft and right prints is small, less than the breadth of individual prints.However, the presence of foot rotation during stance suggests thatdinocephalians used sprawling, rather than parasagittal limb posture. Closespacing of footprints likely resulted from a combination of lateral bending ofthe body and significant cranio-caudal limb excursion, rather than increasedadduction of the limbs under the body.Fil: Blob, Richard W.. Clemson University; Estados UnidosFil: Wilson, Jeffrey A.. University of Michigan; Estados UnidosFil: Marsicano, Claudia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Panko, Laura J.. Northwestern University; Estados UnidosFil: Smith, Roger M.. Iziko South African Museum Cape Town; Sudáfrica77th Annual Meeting of the Society of Vertebrate PaleontologyCanadáSociety of Vertebrate Paleontolog

Fully Geant4 compatible package for the simulation of Dark Matter in fixed target experiments

We present the package for the simulation of DM (Dark Matter) particles in fixed target experiments. The most convenient way of this simulation (and the only possible way in the case of beam-dump) is to simulate it in the framework of the program for tracing particles in the experimental setup. One of the most popular such programs is Geant4. Specifically, the package includes the processes of DM particles production via electron and muon bremsstrahlung off nuclei, resonant in-flight positron annihilation on atomic electrons and gamma to ALP (axion-like particles) conversion on nuclei. Four types of DM mediator particles are considered: vector, scalar, pseudoscalar and axial vector. In particular, for bremsstrahlung the total cross sections are calculated at exact tree level (ETL). The code handles both the case of invisible DM mediator decay and of visible decay into $e^+e^-$ (or into $\gamma \gamma$ in the case of ALP). The software consists of a collection of different classes, inheriting from the Geant4 framework classes, thus the expected use of this package is to include it in a Geant4-based code for the simulation of particles propagation and interaction in the detector. As an example of its usage, we discuss the results obtained from the simulation of a typical active beam-dump experiment, considering $5 \times 10^{12}$ 100 GeV electrons impinging on a lead/plastic scintillator active thick target, showing the expected sensitivity for the four types of DM mediator particles mentioned above.Comment: 10 pages, 4 figure