812 research outputs found

    The Transjurane Highway Dinosaur Tracksites and Their Significance and Application for Ichnological Studies of Dinosaur Palaeobiology

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    As has been unanimously commented upon in previous expert reports (Lockley, 2009; Bates, 2010; Hutchinson, 2010; Stevens, 2010), the dinosaur tracksites of the Transjurane Highway represent an incredible scientific and cultural resource. Having been fortunate enough to spend time visiting the tracksites during September 2010, in particular the Courtedoux—Béchat Bovais and Courtedoux—Sur Combe Ronde tracksites, we were able to see firsthand the extent to which this is overwhelmingly the case. What makes the tracksites globally unique is twofold. Firstly, it is the fossils themselves, of which the sheer number alone is of great consequence, enabling statistical studies into track variation both between and within individual trackways. Even regardless of the abundance of tracks, their preservation is also of great interest to palaeontologists and sedimentologists. Secondly, it is not only the tracks themselves that warrant such praise, but also the methods of documentation that have been carried out as part of the ongoing Palaeontology A16 Project. The methodical collection of data combining traditional ichnological techniques with modern documentation technologies such as high resolution laser scanning and photogrammetry, as well as the collection of specimens and the production of casts has lead to an ichnological research resource that is internationally unparalleled in terms of volume of data and potential accessibility of that data. However, as noted by Hutchinson (2010), documentation, scientific research, and subsequent publication must occur together, for data collection is nothing without published scientific findings, and as expressed by Stevens (2010), the monumental task of carrying out documentation and research simultaneously demands that such work be undertaken collaboratively in order to maximise efficiency. This report aims to present possible research projects that combine the extraordinary data collected by the Palaeontology A16 Project with recent advances in virtual ichnological methods with the hope of producing high impact publications that will become not only a part of global dinosaur track research, but integral to a wide range of palaeobiological studies concerning palaeo(bio)geography, biomechanics, palaeoenvironment and substrate mechanics. It is also important to make data and results accessible, not only to other researchers who can then advance the science further, but to the public as well, in order to educate and inspire future generations of scientists. The remainder of this report is divided into three sections. The first of these sections will outline possible research projects including hypotheses, general methodologies, and the expected time taken to complete the research. The second part will look at how the data and research can be used to both engage with the public and be made more accessible to other researchers. Finally, the third section will discuss the challenges and technical aspects of working with such a volume of digital data as has been, and is currently being, collected by the Palaeontology A16 Project

    A novel approach to studying enclosure and support usage in siamangs (Symphalangus syndactylus): using a 3D computer model

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    This study set out to gain preliminary data to: (1) assess the accuracy of a computer-aided design (CAD) approach in recording the full 3D geometry of a zoo primate enclosure, and (2) evaluate the possibility of using the CAD approach to extract patterns of enclosure use (eg. quantify support availability and preference, and map behavioural data within the 3D enclosure model to visualise, identify and investigate spatial enclosure usage trends). We created two 3D models of the same enclosure in a zoo in the UK housing an adult male, an adult female and a juvenile siamang (Symphalangus syndactylus) using a generic CAD approach and a long-range laser scanner (LiDAR). The CAD model yielded an average geometric error of ~15% in terms of position, height and diameter of structures relative to the LiDAR model. The CAD model was divided into zones to create colour maps of enclosure usage during behaviours such as feeding and foraging, inactivity and locomotion/posture. The CAD model permitted accurate quantification of support availability and identification of exact supports and zones most frequently used for given behaviours. Using the CAD model, apparently underused supports and zones were also identified. We then attempted to determine possible reasons for such infrequent usage. Electivity indexes, a measure of support preference within a particular zone, permitted us to explore why specific supports were preferred over others in the immediate proximity. Electivity indexes were higher for strong horizontal initial supports (mainly poles) during richochetal brachiation indicating they were chosen despite having other support types in close proximity. This suggests the need for a strong horizontal support to generate sufficient propulsive force during push off, to create the flight phase characteristic of richochetal brachiation

    Selective Breeding for a Behavioral Trait Changes Digit Ratio

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    The ratio of the length of the second digit (index finger) divided by the fourth digit (ring finger) tends to be lower in men than in women. This 2D∶4D digit ratio is often used as a proxy for prenatal androgen exposure in studies of human health and behavior. For example, 2D∶4D ratio is lower (i.e. more “masculinized”) in both men and women of greater physical fitness and/or sporting ability. Lab mice have also shown variation in 2D∶4D as a function of uterine environment, and mouse digit ratios seem also to correlate with behavioral traits, including daily activity levels. Selective breeding for increased rates of voluntary exercise (wheel running) in four lines of mice has caused correlated increases in aerobic exercise capacity, circulating corticosterone level, and predatory aggression. Here, we show that this selection regime has also increased 2D∶4D. This apparent “feminization” in mice is opposite to the relationship seen between 2D∶4D and physical fitness in human beings. The present results are difficult to reconcile with the notion that 2D∶4D is an effective proxy for prenatal androgen exposure; instead, it may more accurately reflect effects of glucocorticoids, or other factors that regulate any of many genes

    Equipping for risk: Lessons learnt from the UK shale-gas experience on assessing environmental risks for the future geoenergy use of the deep subsurface

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    \ua9 2024 The Authors. Summary findings are presented from an investigation to improve understanding of the environmental risks associated with developing an unconventional-hydrocarbons industry in the UK. The EQUIPT4RISK project, funded by UK Research Councils, focused on investigations around Preston New Road (PNR), Fylde, Lancashire, and Kirby Misperton Site A (KMA), North Yorkshire, where operator licences to explore for shale gas by hydraulic fracturing (HF) were issued in 2016, although exploration only took place at PNR. EQUIPT4RISK considered atmospheric (greenhouse gases, air quality), water (groundwater quality) and solid-earth (seismicity) compartments to characterise and model local conditions and environmental responses to HF activities. Risk assessment was based on the source-pathway-receptor approach. Baseline monitoring of air around the two sites characterised the variability with meteorological conditions, and isotopic signatures were able to discriminate biogenic methane (cattle) from thermogenic (natural-gas) sources. Monitoring of a post-HF nitrogen-lift (well-cleaning) operation at PNR detected the release of atmospheric emissions of methane (4.2 \ub1 1.4 t CH4). Groundwater monitoring around KMA identified high baseline methane concentrations and detected ethane and propane at some locations. Dissolved methane was inferred from stable-isotopic evidence as overwhelmingly of biogenic origin. Groundwater-quality monitoring around PNR found no evidence of HF-induced impacts. Two approaches for modelling induced seismicity and associated seismic risk were developed using observations of seismicity and operational parameters from PNR in 2018 and 2019. Novel methodologies developed for monitoring include use of machine learning to identify fugitive atmospheric methane, Bayesian statistics to assess changes to groundwater quality, a seismicity forecasting model seeded by the HF-fluid injection rate and high-resolution monitoring of soil-gas methane. The project developed a risk-assessment framework, aligned with ISO 31000 risk-management principles, to assess the theoretical combined and cumulative environmental risks from operations over time. This demonstrated the spatial and temporal evolution of risk profiles: seismic and atmospheric impacts from the shale-gas operations are modelled to be localised and short-lived, while risk to groundwater quality is longer-term

    Intra-trackway morphological variations due to substrate consistency: the El Frontal dinosaur tracksite (Lower Cretaceous, Spain).

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    An ichnological and sedimentological study of the El Frontal dinosaur tracksite (Early Cretaceous, Cameros basin, Soria, Spain) highlights the pronounced intra-trackway variation found in track morphologies of four theropod trackways. Photogrammetric 3D digital models revealed various and distinct intra-trackway morphotypes, which reflect changes in footprint parameters such as the pace length, the track length, depth, and height of displacement rims. Sedimentological analyses suggest that the original substrate was non-homogenous due to lateral changes in adjoining microfacies. Multidata analyses indicate that morphological differences in these deep and shallow tracks represent a part of a continuum of track morphologies and geometries produced by a gradient of substrate consistencies across the site. This implies that the large range of track morphologies at this site resulted from similar trackmakers crossing variable facies. The trackways at the El Frontal site present an exemplary case of how track morphology, and consequently potential ichnotaxa, can vary, even when produced by a single trackmaker

    Manus track preservation bias as a key factor for assessing trackmaker identity and quadrupedalism in basal ornithopods.

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    BACKGROUND: The Las Cerradicas site (Tithonian-Berriasian), Teruel, Spain, preserves at least seventeen dinosaur trackways, some of them formerly attributed to quadrupedal ornithopods, sauropods and theropods. The exposure of new track evidence allows a more detailed interpretation of the controversial tridactyl trackways as well as the modes of locomotion and taxonomic affinities of the trackmakers. METHODOLOGY/PRINCIPAL FINDINGS: Detailed stratigraphic analysis reveals four different levels where footprints have been preserved in different modes. Within the tridactyl trackways, manus tracks are mainly present in a specific horizon relative to surface tracks. The presence of manus tracks is interpreted as evidence of an ornithopod trackmaker. Cross-sections produced from photogrammetric digital models show different depths of the pes and manus, suggesting covariance in loading between the forelimbs and the hindlimbs. CONCLUSIONS/SIGNIFICANCE: Several features (digital pads, length/width ratio, claw marks) of some ornithopod pes tracks from Las Cerradicas are reminiscent of theropod pedal morphology. This morphological convergence, combined with the shallow nature of the manus tracks, which reduces preservation potential, opens a new window into the interpretation of these tridactyl tracks. Thus, trackmaker assignations during the Jurassic-Cretaceous interval of purported theropod trackways may potentially represent ornithopods. Moreover, the Las Cerradicas trackways are further evidence for quadrupedalism among some basal small- to medium-sized ornithopods from this time interval

    Phase transitions in biological membranes

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    Native membranes of biological cells display melting transitions of their lipids at a temperature of 10-20 degrees below body temperature. Such transitions can be observed in various bacterial cells, in nerves, in cancer cells, but also in lung surfactant. It seems as if the presence of transitions slightly below physiological temperature is a generic property of most cells. They are important because they influence many physical properties of the membranes. At the transition temperature, membranes display a larger permeability that is accompanied by ion-channel-like phenomena even in the complete absence of proteins. Membranes are softer, which implies that phenomena such as endocytosis and exocytosis are facilitated. Mechanical signal propagation phenomena related to nerve pulses are strongly enhanced. The position of transitions can be affected by changes in temperature, pressure, pH and salt concentration or by the presence of anesthetics. Thus, even at physiological temperature, these transitions are of relevance. There position and thereby the physical properties of the membrane can be controlled by changes in the intensive thermodynamic variables. Here, we review some of the experimental findings and the thermodynamics that describes the control of the membrane function.Comment: 23 pages, 15 figure

    Using Noun Phrases for Navigating Biomedical Literature on Pubmed: How Many Updates Are We Losing Track of?

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    Author-supplied citations are a fraction of the related literature for a paper. The “related citations” on PubMed is typically dozens or hundreds of results long, and does not offer hints why these results are related. Using noun phrases derived from the sentences of the paper, we show it is possible to more transparently navigate to PubMed updates through search terms that can associate a paper with its citations. The algorithm to generate these search terms involved automatically extracting noun phrases from the paper using natural language processing tools, and ranking them by the number of occurrences in the paper compared to the number of occurrences on the web. We define search queries having at least one instance of overlap between the author-supplied citations of the paper and the top 20 search results as citation validated (CV). When the overlapping citations were written by same authors as the paper itself, we define it as CV-S and different authors is defined as CV-D. For a systematic sample of 883 papers on PubMed Central, at least one of the search terms for 86% of the papers is CV-D versus 65% for the top 20 PubMed “related citations.” We hypothesize these quantities computed for the 20 million papers on PubMed to differ within 5% of these percentages. Averaged across all 883 papers, 5 search terms are CV-D, and 10 search terms are CV-S, and 6 unique citations validate these searches. Potentially related literature uncovered by citation-validated searches (either CV-S or CV-D) are on the order of ten per paper – many more if the remaining searches that are not citation-validated are taken into account. The significance and relationship of each search result to the paper can only be vetted and explained by a researcher with knowledge of or interest in that paper

    Digit Ratio Predicts Sense of Direction in Women

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    The relative length of the second-to-fourth digits (2D:4D) has been linked with prenatal androgen in humans. The 2D:4D is sexually dimorphic, with lower values in males than females, and appears to correlate with diverse measures of behavior. However, the relationship between digit ratio and cognition, and spatial cognition in particular, has produced mixed results. In the present study, we hypothesized that spatial tasks separating cue conditions that either favored female or male strategies would examine this structure-function correlation with greater precision. Previous work suggests that males are better in the use of directional cues than females. In the present study, participants learned a target location in a virtual landscape environment, in conditions that contained either all directional (i.e., distant or compass bearing) cues, or all positional (i.e., local, small objects) cues. After a short delay, participants navigated back to the target location from a novel starting location. Males had higher accuracy in initial search direction than females in environments with all directional cues. Lower digit ratio was correlated with higher accuracy of initial search direction in females in environments with all directional cues. Mental rotation scores did not correlate with digit ratio in either males or females. These results demonstrate for the first time that a sex difference in the use of directional cues, i.e., the sense of direction, is associated with more male-like digit ratio.National Science Foundation (U.S.) (NSF ECCS-1028319)National Science Foundation (U.S.) (NSF Graduate Student Fellowship)Mary Elisabeth Rennie Endowment for Epilepsy Researc
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