2,613 research outputs found

    A new partial skeleton of a cryptocleidoid plesiosaur from the Upper Jurassic Sundance Formation of Wyoming

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    Cryptocleidoid plesiosaurs from the Upper Jurassic are well known from the Oxford Clay (Callovian) of the United Kingdom. The plesiosaurs of the nearly coeval Sundance Formation (Oxfordian) of North America are poorly known, but are thought to include two cryptocleidoid taxa:Pantosaurus striatus and Tatenectes laramiensis. Here we present two specimens recently recovered from the Bighorn Basin of Wyoming. The first specimen comprises three articulated adult cervical vertebrae and fragments of a fourth. This specimen preserves a posteriorly directed cervical neural spine, a character diagnostic of Pantosaurus striatus. It also resembles Pantosaurus in the morphology of its cervical rib articulations. The second specimen is a partial articulated skeleton comprising a complete pelvic girdle, dorsal, sacral, and caudal vertebrae, and numerous ribs and gastralia. This specimen displays a number of unique characters, including posteriorly directed dorsal, sacral, and caudal neural spines, highly autapomorphic illia, and a pathologically asymmetric pelvic girdle. Despite the lack of overlapping material, it is tentatively referred to Pantosaurus on the basis of posteriorly directed neural spines. These specimens represent the first significant adult material provisionally referable to Pantosaurus striatus, as well as the first posterior axial column and pelvic girdle

    Private Schools: Partners in American Education – Overview and Directions for Further Research

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    Families of Small Regular Graphs of Girth 5

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    In this paper we obtain (q+3)(q+3)--regular graphs of girth 5 with fewer vertices than previously known ones for q=13,17,19q=13,17,19 and for any prime q≥23q \ge 23 performing operations of reductions and amalgams on the Levi graph BqB_q of an elliptic semiplane of type C{\cal C}. We also obtain a 13-regular graph of girth 5 on 236 vertices from B11B_{11} using the same technique

    The vertebrate fauna of the Upper Permian of Niger—III, morphology and ontogeny of the hindlimb of Moradisaurus grandis (Reptilia, Captorhinidae)

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    We describe hindlimb elements of the large captorhinid Moradisaurus grandis (Reptilia: Captorhinidae) recently collected from the Upper Permian Moradi Formation of north-central Niger. This description is based primarily on an associated partial skeleton comprising a hemimandible, vertebral column, and partial left and nearly complete right hindlimb. Additionally, we report on a well-preserved, articulated, and essentially complete juvenile pes that provides important information on the ontogeny of the captorhinid tarsus. The hindlimb of Moradisaurus is stout and more massively built than in any other known captorhinid. The femur displays several features interpreted as adaptations to the demands of large body size, and the tibia and fibula have short, wide shafts and hypertrophied condyles and epicondyles. The astragalus is very derived, possessing two accessory ossifications and a relatively horizontal tibial articulation, indicating that the tibia was held more vertically than in other captorhinids. The calcaneum is co-ossified with distal tarsal five. The juvenile pes indicates that the captorhinid centrale arose from the fusion of two ossification centers, and that the captorhinid astragalus arose from the fusion of at least three ossification centers

    A new skeleton of the cryptoclidid plesiosaur Tatenectes laramiensis reveals a novel body shape among plesiosaurs

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    Current knowledge of plesiosaurs of clade Cryptoclidia is constrained by a lack of fossils from outside the Oxford Clay deposits of England. Recent fieldwork in the Sundance Formation of the Bighorn Basin, Wyoming, has resulted in the recovery of significant new fossils of cryptoclidid plesiosaurs, including the small-bodied form Tatenectes laramiensis. A new partial skeleton of this taxon is reported here; it is the most complete and best-preserved example of the taxon found to date, comprising a complete dorsal vertebral series, many ribs and gastralia, and a complete pelvic girdle. This skeleton illuminates several unique features of the taxon, including a novel pattern of midline pachyostosis in the gastralia. In addition, a range of both axial and appendicular morphological features reveals that Tatenectes had a body shape unique among known plesiosaurs, characterized by extreme dorsoventral compression, and modest anteroposterior reduction. The combination of the new skeleton with information from previous finds allows the first reconstruction of the taxon. Tatenectes had a dorsoventrally compressed, oblate spheroid body shape, with a high skeletal mass concentration in the ventral elements. We hypothesize that these features were adaptations for increased near-surface stability, perhaps allowing access to above normal wave base, inshore environments in the shallow Sundance Seaway

    Advancing Social Determinants of Health Through Investments in Postsecondary Attainment and Sustaining Employment

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    In 2018, the Humana Foundation shifted the focus of its work to the social determinants of health, with the key aim of promoting health equity. With this new focus came a recognition that larger, long-term investments would be needed to support strategies addressing upstream determinants of health. The foundation also recognized the need to co-create processes with communities to understand how to provide essential holistic supports. This article explores one area of the foundation’s new efforts, the Strategic Community Investment Program, which focuses in part on postsecondary attainment and sustaining employment. The foundation partnered with the University of Louisville’s Center for Health Organization Transformation to systematically review models in the literature of successful postsecondary attainment strategies to evaluate the results in communities. This article shares key learnings from the literature and coordinated practice in communities that were used to revise the foundation’s strategy, and concludes with suggestions for other foundations interested in addressing postsecondary attainment and other social determinants of health to better meet the challenges and opportunities of the communities they serve

    Novelty and anxiolytic drugs dissociate two components of hippocampal theta in behaving rats

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    Hippocampal processing is strongly implicated in both spatial cognition and anxiety and is temporally organized by the theta rhythm. However, there has been little attempt to understand how each type of processing relates to the other in behaving animals, despite their common substrate. In freely moving rats, there is a broadly linear relationship between hippocampal theta frequency and running speed over the normal range of speeds used during foraging. A recent model predicts that spatial-translation-related and arousal/anxiety-related mechanisms of hippocampal theta generation underlie dissociable aspects of the theta frequency–running speed relationship (the slope and intercept, respectively). Here we provide the first confirmatory evidence: environmental novelty decreases slope, whereas anxiolytic drugs reduce intercept. Variation in slope predicted changes in spatial representation by CA1 place cells and novelty-responsive behavior. Variation in intercept predicted anxiety-like behavior. Our findings isolate and doubly dissociate two components of theta generation that operate in parallel in behaving animals and link them to anxiolytic drug action, novelty, and the metric for self-motion
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