292 research outputs found

    The critical earthquake concept applied to mine rockbursts with time-to-failure analysis

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    We report new tests of the critical earthquake concepts performed on rockbursts in deep South African mines. We extend the concept of an optimal time and space correlation region and test it on the eight main shocks of our catalog provided by ISSI. In a first test, we use the simplest signature of criticality in terms of a power law time-to-failure formula. Notwithstanding the fact that the search for the optimal correlation size is performed with this simple power law, we find evidence both for accelerated seismicity and for the presence of logperiodic behavior with a prefered scaling factor close to 2. We then propose a new algorithm based on a space and time smoothing procedure, which is also intended to account for the finite range and time mechanical interactions between events. This new algorithm provides a much more robust and efficient construction of the optimal correlation region, which allows us the use of the logperiodic formula directly in the search process. In this preliminary work, we have only tested the new algorithm on the largest event on the catalog. The result is of remarkable good quality with a dramatic improvement in accuracy and robustness. This confirms the potential importance of logperiodic signals. Our study opens the road for an efficient implemention of a systematic testing procedure of real-time predictions.Comment: 22 pages, 32 figure

    Deciphering the genome structure and paleohistory of _Theobroma cacao_

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    We sequenced and assembled the genome of _Theobroma cacao_, an economically important tropical fruit tree crop that is the source of chocolate. The assembly corresponds to 76% of the estimated genome size and contains almost all previously described genes, with 82% of them anchored on the 10 _T. cacao_ chromosomes. Analysis of this sequence information highlighted specific expansion of some gene families during evolution, for example flavonoid-related genes. It also provides a major source of candidate genes for _T. cacao_ disease resistance and quality improvement. Based on the inferred paleohistory of the T. cacao genome, we propose an evolutionary scenario whereby the ten _T. cacao_ chromosomes were shaped from an ancestor through eleven chromosome fusions. The _T. cacao_ genome can be considered as a simple living relic of higher plant evolution

    Pre-eruptive magmatic processes re-timed using a non-isothermal approach to magma chamber dynamics

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    Open Source PaperThis work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. The attached file is the published version of the article

    Personality factors in exercise addiction: a pilot study exploring the role of narcissism, extraversion, and agreeableness

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    Despite the increased evidence and acceptance of exercise being classed as a behavioral addiction, there is limited research examining personality characteristics within exercise addicts. The purpose of this study was to examine three personality traits (narcissism, extraversion, and agreeableness) and to examine their role in exercise addiction. The sample comprised 114 voluntary participants (74 females and 40 males) who completed the (i) Exercise Addiction Inventory, (ii) Narcissistic Personality Inventory, and (iii) Ten-Item Personality Inventory, as well as demographic questions and questions concerning their engagement and intensity levels of exercise. Results indicated a low incidence of individuals who were classed as at risk of exercise addiction (7%), but a high incidence of symptomatic individuals (75%). Results suggested that extraversion and narcissism may be underlying factors in exercise addiction with no effect for agreeableness. Exercise engagement and intensity were also related to exercise addiction. Further research examining the relationship between personality types and exercise addiction may be useful in identifying individuals at risk for developing exercise addiction

    An extraterrestrial trigger for the Early Cretaceous massive volcanism? Evidence from the paleo-Tethys Ocean

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    The Early Cretaceous Greater Ontong Java Event in the Pacific Ocean may have covered ca. 1% of the Earth's surface with volcanism. It has puzzled scientists trying to explain its origin by several mechanisms possible on Earth, leading others to propose an extraterrestrial trigger to explain this event. A large oceanic extraterrestrial impact causing such voluminous volcanism may have traces of its distal ejecta in sedimentary rocks around the basin, including the paleo-Tethys Ocean which was then contiguous with the Pacific Ocean. The contemporaneous marine sequence at central Italy, containing the sedimentary expression of a global oceanic anoxic event (OAE1a), may have recorded such ocurrence as indicated by two stratigraphic intervals with 187Os/188Os indicative of meteoritic influence. Here we show, for the first time, that platinum group element abundances and inter-element ratios in this paleo-Tethyan marine sequence provide no evidence for an extraterrestrial trigger for the Early Cretaceous massive volcanism

    Antiretroviral-naive and -treated HIV-1 patients can harbour more resistant viruses in CSF than in plasma

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    Objectives The neurological disorders in HIV-1-infected patients remain prevalent. The HIV-1 resistance in plasma and CSF was compared in patients with neurological disorders in a multicentre study. Methods Blood and CSF samples were collected at time of neurological disorders for 244 patients. The viral loads were >50 copies/mL in both compartments and bulk genotypic tests were realized. Results On 244 patients, 89 and 155 were antiretroviral (ARV) naive and ARV treated, respectively. In ARV-naive patients, detection of mutations in CSF and not in plasma were reported for the reverse transcriptase (RT) gene in 2/89 patients (2.2%) and for the protease gene in 1/89 patients (1.1%). In ARV-treated patients, 19/152 (12.5%) patients had HIV-1 mutations only in the CSF for the RT gene and 30/151 (19.8%) for the protease gene. Two mutations appeared statistically more prevalent in the CSF than in plasma: M41L (P = 0.0455) and T215Y (P = 0.0455). Conclusions In most cases, resistance mutations were present and similar in both studied compartments. However, in 3.4% of ARV-naive and 8.8% of ARV-treated patients, the virus was more resistant in CSF than in plasma. These results support the need for genotypic resistance testing when lumbar puncture is performe

    Hints of Universality from Inflection Point Inflation

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    This work aims to understand how cosmic inflation embeds into larger models of particle physics and string theory. Our work operates within a weakened version of the Landscape paradigm, wherein it is assumed that the set of possible Lagrangians is vast enough to admit the notion of a generic model. By focusing on slow-roll inflation, we examine the roles of both the scalar potential and the space of couplings which determine its precise form. In particular, we focus on the structural properties of the scalar potential, and find a surprising result: inflection point inflation emerges as an important —and under certain assumptions, dominant — possibility in the context of generic scalar potentials. We begin by a systematic coarse graining over the set of possible inflection point inflation models using V.I. Arnold’s ADE classification of singularities. Similar to du Val’s pioneering work on surface singularities, these determine structural classes for inflection point inflation which depened on a distinct number of control parameters. We consider both single and multifield inflation, and show how the various structural classes embed within each other. We also show how such control parameters influence the larger physical models in to which inflation is embedded. These techniques are then applied to both MSSM inflation and KKLT-type models of string cosmology. In the former case, we find that the scale of inflation can be entirely encoded within the super- potential of supersymmetric quantum field theories. We show how this relieves the fine-tuning required in such models by upwards of twelve orders of magnitude. Moreover, unnatural tuning between SUSY breaking and SUSY preserving sectors is eliminated without the explicit need for any hidden sector dynamics. In the later case, we discuss how structural stability vastly generalizes — and addresses — the Kallosh-Linde problem. Implications for the spectrum of SUSY breaking soft terms are then discussed, with an emphasis on how they may assist in constraining the inflationary scalar potential. We then pivot to a general discussion of the FLRW-scalar phase space, and show how inflection points induce caustics — or dynamical fixed points — amongst the space of possible trajectories. These fixed points are then used to argue that for uninformative priors on the space of couplings, the likelihood of inflection point inflation scales with the inverse cube of the number of e-foldings. We point out the geometric origin for the known ambiguity in the Liouville measure, and demonstrate of inflection point inflation ameliorates this problem. Finally we investigate the effect of the fixed point structure on the spectrum of density perturbations. We show how an anomaly in the Cosmic Mircowave Background data — low power at large scales — can be explained as a by product of the fixed point dynamics
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