1,127 research outputs found

    Pterosaurs of the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight, southern England: a review with new data

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    Micropalaeontological processing of vertebrate-bearing horizons within the Early Cretaceous (Barremian) Wessex Formation of the Isle of Wight, southern England, reveals a rare, but diverse assemblage of pterosaurs. Besides the previously known euornithocheiran Caulkicephalus, the new material demonstrates the presence of three species of istiodactylid, a ctenochasmatid, and a distinct form that cannot easily be placed in a higher taxon. This elevated diversity is in keeping with pterosaur diversity from other Early Cretaceous localities, having some similarities with assemblages from the Early Cretaceous of Brazil, China and Spain. The apparent absence of toothless forms in the Wessex Formation may represent a preservation bias or collecting artefact.El análisis micropaleontológico de los niveles estratigráficos ricos en vertebrados del Barremiense (Cretácico Inferior) de la Formacion Wessex en la Isla de Wight al sur de Inglaterra, demuestra la presencia de una escasa aunque diversa asociacion de pterosaurios. Ademas del conocido euornitoqueriaceo Caulkicephalus los nuevos hallazgos han revelado la presencia de tres especies pertenecientes a las familias Istiodactylidae, un taxon de Ctenochasmatidae, y un taxon singular de difícil atribucion a nivel taxonomico superior. Esta gran diversidad es coherente con la de otras localidades del Cretacico Inferior, y tiene algunas semejanzas con asociaciones del Cretacico Inferior de Brasil, China y Espana. La aparente ausencia de formas edentadas en la Formacion Wessex puede ser debida a un sesgo de conservacion o a un artefacto relacionado con la colecta de ejemplares

    Failure to report protocol violations in clinical trials: a threat to internal validity?

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    <p>Abstract</p> <p>Background</p> <p>Excessive protocol violations (PV), which can be defined as preventable mistakes in study conduct, may result in patient harm and introduce errors into a clinical trial's results leading to flawed trial conclusions.</p> <p>The purpose of this project was to gain a better understanding of reported PVs, to describe current practice with regards to the use of methods for the reduction of PVs and to investigate relationships between clinical trial characteristics and PVs.</p> <p>Methods</p> <p>We reviewed 80 clinical trials conducted across a broad range of medical specialties published in four major general medical journals (The Lancet, NEJM, JAMA, BMJ). Eligible papers were identified using a PubMed search. For each included trial, two authors independently abstracted information on trial characteristics, PV reporting and PV rates and interventions used to reduce PVs. PVs were categorised into one of five distinct types: enrolment, randomisation, study intervention, patient compliance and data collection errors. Associations between PVs and study characteristics were investigated using logistic regression.</p> <p>Results</p> <p>Eighty clinical trials (20 from each journal) were identified from 101 consecutive PubMed abstracts. The median number of participants was 701 (range: 20 to 162, 367) and the median number of participating sites was 15 (range: 1 to 701). Nineteen percent (15/80) of included trials were single centre trials. The median study duration was 24 months (range: 5.81 - 127 months) and 74% (59/80) of included trials were primarily academic funded.</p> <p>Thirty two percent (26/80) of included trials failed to provide explicit reporting of any type of PV and none (0/80) of the trials provided explicit reporting of all five types of PVs. Larger clinical trials (more patients, more sites, longer duration, more complex management structure) were more likely to have more complete reporting of PV's.</p> <p>Only 9% (7/80) of trials reported the use of a specific study method to prevent PVs. Use of a run-in phase was the only method reported.</p> <p>Conclusions</p> <p>PVs are under-reported. Although the CONSORT statement provides guidance on the reporting of PVs, reporting requirements are not explicit for all types of PVs. As a first step towards improved reporting by authors, we recommend the CONSORT statement highlight the importance of PVs by making reporting requirements more explicit.</p

    Admiration regulates social hierarchy:Antecedents, dispositions, and effects on intergroup behavior

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    In four studies, we report evidence that admiration affects intergroup behaviors that regulate social hierarchy. We demonstrate that manipulating the legitimacy of status relations affects admiration for the dominant and that this emotion negatively predicts political action tendencies aimed at social change. In addition, we show that greater warmth and competence lead to greater admiration for an outgroup, which in turn positively predicts deferential behavior and intergroup learning. We also demonstrate that, for those with a disposition to feel admiration, increasing admiration for an outgroup decreases willingness to take political action against that outgroup. Finally, we show that when the object of admiration is a subversive “martyr,” admiration positively predicts political action tendencies and behavior aimed at challenging the status quo. These findings provide the first evidence for the important role of admiration in regulating social hierarchy

    Simulated structure and imaging of NTCDI on Si(1 1 1)-7 × 7 : a combined STM, NC-AFM and DFT study

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    The adsorption of naphthalene tetracarboxylic diimide (NTCDI) on Si(1 1 1)-7 × 7 is investigated through a combination of scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM) and density functional theory (DFT) calculations. We show that NTCDI adopts multiple planar adsorption geometries on the Si(1 1 1)-7 × 7 surface which can be imaged with intramolecular bond resolution using NC-AFM. DFT calculations reveal adsorption is dominated by covalent bond formation between the molecular oxygen atoms and the surface silicon adatoms. The chemisorption of the molecule is found to induce subtle distortions to the molecular structure, which are observed in NC-AFM images

    Invertebrate communities on historical shipwrecks in the western Atlantic : relation to islands

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    Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 566 (2017): 17-29, doi:10.3354/meps12058.Shipwrecks can be considered island-like habitats on the seafloor. We investigated the fauna of eight historical shipwrecks off the east coast of the U.S. to assess whether species distribution patterns on the shipwrecks fit models from classical island theory. Invertebrates on the shipwrecks included both sessile (sponges, anemones, hydroids) and motile (crustaceans, echinoderms) species. Invertebrate communities were significantly different among wrecks. The size and distance between wrecks influenced the biotic communities, much like on terrestrial islands. However, while wreck size influenced species richness (alpha diversity), distance to the nearest wreck influenced community composition (beta diversity). Alpha and beta diversity on the shipwrecks were thus influenced by different abiotic factors. We found no evidence of either nested patterns or non-random co-occurrence of morphotypes, suggesting that the taxa on a given shipwreck were randomly selected from the available taxon pool. Species present on the shipwrecks generally had one of two reproductive modes: most motile or solitary sessile species had long-duration planktotrophic larvae, while most encrusting or colonial sessile species had short-duration lecithotrophic larvae and underwent asexual reproduction by budding as adults. Short-duration larvae may recruit to their natal shipwreck, allowing them to build up dense populations and dominate the wreck surfaces. A high degree of dominance was indeed observed on the wrecks, with up to 80% of the fauna being accounted for by the most common species alone. By comparing the shipwreck communities to known patterns of succession in shallow water, we hypothesize that the shipwrecks are in a stage of mid-succession.This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-0829517. Funding for this project was supplied by the Bureau of Ocean Energy Management (BOEM), under contract to CSA Ocean Sciences, Inc. (contract M10PC00100) in partnership with the National Oceanographic 377 Partnership Program

    Examining the restorative effects of casual video games

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    Individuals who work in highly stressful jobs (e.g. doctors, soldiers) struggle with the daily impact of stress-related cognitive fatigue. High-pressured job tasks and worry for job security can produce an unstable internal environment for the individual, where stress and cognitive workload can intensify. Stress-induced fatigue generates a multitude of overwhelming problems for the individual. Due to society’s growing demand of productivity and efficiency, there is an essential need for finding a cost effective way to reduce cognitive fatigue and stress for everyone. This study analyzed and compared three relaxation methods (break, meditation, & game) to determine the effectiveness of brief casual video game exposure as a method to reduce stress increase mood, and restore cognitive resources. Taking a short break or engaging in guided relaxation exercises are well-known methods for reducing stress and improving mood, but can be impractical, less motivating, and time-consuming in a high stress related job, where time-efficiency and productivity are critical. Casual Video Games (CVGs) may present an optimum opportunity to be a preferred method to reduce stress and improve mood, due to their short time requirements, better mobility, and convenience. Three experiments were conducted to examine the hypothesis that CVGs could be an efficacious method of reducing stress, improving mood and restoring fatigue induced cognitive decrements. Across all three experiments, the guided medication technique was found to be another effective method to reduce stress and improve mood; however, this method was found to be less effective than the casual video game condition, the break was found to be the least effective method of reducing stress and improving mood. However, none of the methods were able to improve cognitive functioning. Overall, the results indicated that briefly playing a casual video game (\u3c 10 minutes) can improve mood (increased positive affect & reduced negative affect), reduce stress with increased task engagement. Widespread use of Casual Video Games has the potential of improving employee productivity and efficiency and therefore improving a company’s profitability. Future research is needed to determine which aspects of casual video games may increase or reduce these effects

    Conflict, what conflict?: Evidence that playing down ‘conflict’ can be a weapon of choice for high‐status groups

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThree studies using pre‐existing (Studies 1 and 3) and minimal (Study 2) groups tested the hypothesis that ingroup status shapes whether ‘conflict’ with an outgroup is strategically acknowledged or downplayed. As predicted, high (vs. low) ingroup status led group members to downplay conflict, but only to an outgroup rather than ingroup audience (Studies 1 & 2; Ns = 127 & 292), and only when the status difference was unstable (vs. stable) and the outgroup’s action was perceived as illegitimate (Study 2). High‐status group members also collectively communicated with the outgroup in a manner designed to defuse conflict (Study 2). Survey data of industrial (manager‐worker) relations further indicated that company managers (high‐status) characterized manager–worker relations as less conflictual than did workers (low‐status) in the same companies (Study 3; N = 24,661). Findings imply that high‐status groups play down conflict as a ‘benevolent’ (but unacknowledged) means of maintaining intergroup status hierarchies

    SALL4 Expression in Gonocytes and Spermatogonial Clones of Postnatal Mouse Testes

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    The spermatogenic lineage is established after birth when gonocytes migrate to the basement membrane of seminiferous tubules and give rise to spermatogonial stem cells (SSC). In adults, SSCs reside within the population of undifferentiated spermatogonia (Aundiff) that expands clonally from single cells (Asingle) to form pairs (Apaired) and chains of 4, 8 and 16 Aaligned spermatogonia. Although stem cell activity is thought to reside in the population of Asingle spermatogonia, new research suggests that clone size alone does not define the stem cell pool. The mechanisms that regulate self-renewal and differentiation fate decisions are poorly understood due to limited availability of experimental tools that distinguish the products of those fate decisions. The pluripotency factor SALL4 (sal-like protein 4) is implicated in stem cell maintenance and patterning in many organs during embryonic development, but expression becomes restricted to the gonads after birth. We analyzed the expression of SALL4 in the mouse testis during the first weeks after birth and in adult seminiferous tubules. In newborn mice, the isoform SALL4B is expressed in quiescent gonocytes at postnatal day 0 (PND0) and SALL4A is upregulated at PND7 when gonocytes have colonized the basement membrane and given rise to spermatogonia. During steady-state spermatogenesis in adult testes, SALL4 expression overlapped substantially with PLZF and LIN28 in Asingle, Apaired and Aaligned spermatogonia and therefore appears to be a marker of undifferentiated spermatogonia in mice. In contrast, co-expression of SALL4 with GFRα1 and cKIT identified distinct subpopulations of Aundiff in all clone sizes that might provide clues about SSC regulation. Collectively, these results indicate that 1) SALL4 isoforms are differentially expressed at the initiation of spermatogenesis, 2) SALL4 is expressed in undifferentiated spermatogonia in adult testes and 3) SALL4 co-staining with GFRα1 and cKIT reveals distinct subpopulations of Aundiff spermatogonia that merit further investigation. © 2013 Gassei, Orwig
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