57 research outputs found

    Scale-dependent influence of pre-existing basement shear zones on rift faulting : a case study from NE Brazil

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    Rifting of continental crust initiates faults that are commonly influenced by pre-existing structures. We document newly identified faults cutting Precambrian units in the interior of the NE Brazilian margin to assess the effects of structural inheritance on both rift geometry and fault architecture. Stratigraphic and structural data indicate that the faults were active in the main phase of rifting of Gondwana. The influence of pre-existing structures on the Mesozoic rift faulting is scale dependent. Regionally, the faults trend parallel to subvertical, crustal-scale Brasiliano (c. 750–540 Ma) shear zones. Mylonitic foliations and broadly distributed low strain in the lower crust indicated by shear-wave splitting controlled the overall orientation and kinematics of the rift faults. However, outcrop observations of the faults show that at scales up to hundreds of metres, mylonitic foliations have little influence on fault architectures. Faults cross-cut shear zones and do not commonly utilize foliation planes as shear fractures. Instead, slip zones and fractures have a range of orientations that form acute angles to the local foliation orientation. This observation explains the range of focal mechanisms associated with seismicity that coincides with ancient shear zones in intra-continental areas

    Convergence of Quantum Annealing with Real-Time Schrodinger Dynamics

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    Convergence conditions for quantum annealing are derived for optimization problems represented by the Ising model of a general form. Quantum fluctuations are introduced as a transverse field and/or transverse ferromagnetic interactions, and the time evolution follows the real-time Schrodinger equation. It is shown that the system stays arbitrarily close to the instantaneous ground state, finally reaching the target optimal state, if the strength of quantum fluctuations decreases sufficiently slowly, in particular inversely proportionally to the power of time in the asymptotic region. This is the same condition as the other implementations of quantum annealing, quantum Monte Carlo and Green's function Monte Carlo simulations, in spite of the essential difference in the type of dynamics. The method of analysis is an application of the adiabatic theorem in conjunction with an estimate of a lower bound of the energy gap based on the recently proposed idea of Somma et. al. for the analysis of classical simulated annealing using a classical-quantum correspondence.Comment: 6 pages, minor correction

    The relationship between frailty and social vulnerability: a systematic review

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    Both frailty (reduced physiological reserve) and social vulnerability (scarcity of adequate social connections, support, or interaction) become more common as people age and are associated with adverse consequences. Analyses of the relationships between these constructs can be limited by the wide range of measures used to assess them. In this systematic review, we synthesised 130 observational studies assessing the association between frailty and social vulnerability, the bidirectional longitudinal relationships between constructs, and their joint associations with adverse health outcomes. Frailty, across assessment type, was associated with increased loneliness and social isolation, perceived inadequacy of social support, and reduced social participation. Each of these social vulnerability components was also associated with more rapid progression of frailty and lower odds of improvement compared with the absence of that social vulnerability component (eg, more rapid frailty progression in people with social isolation vs those who were not socially isolated). Combinations of frailty and social vulnerability were associated with increased mortality, decline in physical function, and cognitive impairment. Clinical and public health measures targeting frailty or social vulnerability should, therefore, account for both frailty and social vulnerability

    Frailty and socioeconomic position: a systematic review of observational studies

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    Background: Frailty, an age-related state of reduced physiological reserve, is often associated with lower socio-economic position (SEP). This systematic review synthesised observational studies assessing (i) the association between SEP and frailty prevalence; (ii) how changes in frailty status over time vary by SEP; and (iii) whether the association between frailty and clinical outcomes is modified by SEP. Methods: We searched three electronic databases from 2001 to 2023. We included observational studies measuring early-, mid-, and late-life indicators of SEP (education, income, wealth, housing, occupation, and area-based measures of multiple deprivation) and frailty (assessed using any validated measure). Screening and extraction were performed in duplicate. Findings were synthesised using narrative synthesis. Results: We included 383 studies reporting findings from 265 independent samples/cohorts across 64 countries. Lower SEP was associated with higher frailty prevalence across all indicators (childhood deprivation 7/8 studies, education 227/248, occupation 28/32, housing 8/9, income 98/108, wealth 39/44 and area-based deprivation 32/34). Lower SEP was also associated with higher frailty incidence (27/30), with greater odds of transitioning towards a more severe frailty state (35/43), lower odds of frailty reversion (7/11), and (in some studies) with more rapid accumulation of deficits (7/15). The relationship between frailty and mortality was not modified by SEP. Interpretation: Preventative measures across multiple levels of individual and structural inequality are likely to be required to reduce the rising levels of frailty. Resourcing of interventions and services to support people living with frailty should be proportionate to needs in the population to avoid widening existing health inequalities

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Some basic aspects of quantum phase transitions

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    Several basic problems of the theory of quantum phase transitions are reviewed. The effect of the quantum correlations on the phase transition properties is considered with the help of basic models of statistical physics. The effect of quenched disorder on the quantum phase transitions is also discussed. The review is performed within the framework of the thermodynamic scaling theory and by the most general methods of statistical physics for the treatment of phase transitions: general length-scale arguments, exact solutions, mean field approximation, Hubbard-Stratonovich transformation, Feynman path integral approach, and renormalization group in the field theoretical variant. Some new ideas and results are presented. Outstanding theoretical problems are mentioned.Comment: 81 pages, Latex2e, 8 figures, Phys. Rep.(2003) in pres

    Physiological parameters for Prognosis in Abdominal Sepsis (PIPAS) Study : a WSES observational study

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    BackgroundTiming and adequacy of peritoneal source control are the most important pillars in the management of patients with acute peritonitis. Therefore, early prognostic evaluation of acute peritonitis is paramount to assess the severity and establish a prompt and appropriate treatment. The objectives of this study were to identify clinical and laboratory predictors for in-hospital mortality in patients with acute peritonitis and to develop a warning score system, based on easily recognizable and assessable variables, globally accepted.MethodsThis worldwide multicentre observational study included 153 surgical departments across 56 countries over a 4-month study period between February 1, 2018, and May 31, 2018.ResultsA total of 3137 patients were included, with 1815 (57.9%) men and 1322 (42.1%) women, with a median age of 47years (interquartile range [IQR] 28-66). The overall in-hospital mortality rate was 8.9%, with a median length of stay of 6days (IQR 4-10). Using multivariable logistic regression, independent variables associated with in-hospital mortality were identified: age > 80years, malignancy, severe cardiovascular disease, severe chronic kidney disease, respiratory rate >= 22 breaths/min, systolic blood pressure 4mmol/l. These variables were used to create the PIPAS Severity Score, a bedside early warning score for patients with acute peritonitis. The overall mortality was 2.9% for patients who had scores of 0-1, 22.7% for those who had scores of 2-3, 46.8% for those who had scores of 4-5, and 86.7% for those who have scores of 7-8.ConclusionsThe simple PIPAS Severity Score can be used on a global level and can help clinicians to identify patients at high risk for treatment failure and mortality.Peer reviewe

    State of the Climate in 2016

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    Combining 2D and 3D Views for Orientation and Relative Position Tasks

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    We compare 2D/3D combination displays to displays with 2D and 3D views alone. Combination displays we consider are: orientation icon (i.e., side-by-side), in-place methods (e.g., clip planes), and a new method called ExoVis. We specifically analyze performance differences (i.e., time and accuracy) for 3D orientation and relative position tasks. Empirical results show that 3D displays are effective for approximate navigation and relative positioning whereas 2D/3D combination displays (orientation icon and ExoVis) are useful for precise orientation and position tasks. Combination 2D/3D displays had as good or better performance as 2D displays. Clip planes were not effective for a 3D orientation task, but may be useful when only one slice is needed. Author Keywords 2D and 3D visualization, display design, empirical study, experiment, orientation and relative position tasks

    Visualization task performance with 2D, 3D, and combination displays

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    Abstract—We describe a series of experiments that compare 2D displays, 3D displays, and combined 2D/3D displays (orientation icon, ExoVis, and clip planes) for relative position estimation, orientation, and volume of interest tasks. Our results indicate that 3D displays can be very effective for approximate navigation and relative positioning when appropriate cues, such as shadows, are present. However, 3D displays are not effective for precise navigation and positioning except possibly in specific circumstances, for instance, when good viewing angles or measurement tools are available. For precise tasks in other situations, orientation icon and ExoVis displays were better than strict 2D or 3D displays (displays consisting exclusively of 2D or 3D views). The combined displays had as good or better performance, inspired higher confidence, and allowed natural, integrated navigation. Clip plane displays were not effective for 3D orientation because users could not easily view more than one 2D slice at a time and had to frequently change the visibility of individual slices. Major factors contributing to display preference and usability were task characteristics, orientation cues, occlusion, and spatial proximity of views that were used together. Index Terms—User interfaces, graphical user interfaces (GUI), screen design, evaluation/methodology, picture/image generation, display algorithms, CAD, medical imaging.
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