653 research outputs found

    Abelian homotopy Dijkgraaf-Witten theory

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    We construct a version of Dijkgraaf-Witten theory based on a compact abelian Lie group within the formalism of Turaev's homotopy quantum field theory. As an application we show that the 2+1-dimensional theory based on U(1) classifies lens spaces up to homotopy type.Comment: 23 pages, 1 figur

    Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be

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    Regolith-mantled hillslopes are ubiquitous features of most temperate landscapes, and their morphology reflects the climatically, biologically, and tectonically mediated interplay between regolith production and downslope transport. Despite intensive research, few studies have quantified both of these mass fluxes in the same field site. Here we present an analysis of 87 meteoric 10Be measurements from regolith and bedrock within the Susquehanna Shale Hills Critical Zone Observatory (SSHO), in central Pennsylvania. Meteoric 10Be concentrations in bulk regolith samples (n=73) decrease with regolith depth. Comparison of hillslope meteoric 10Be inventories with analyses of rock chip samples (n=14) from a 24 m bedrock core confirms that >80% of the total inventory is retained in the regolith. The systematic downslope increase of meteoric 10Be inventories observed at SSHO is consistent with 10Be accumulation in slowly creeping regolith (∼ 0.2 cm yr-1). Regolith flux inferred from meteoric 10Be varies linearly with topographic gradient (determined from high-resolution light detection and ranging-based topography) along the upper portions of hillslopes at SSHO. However, regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick, near the base of hillslopes. Meteoric 10Be inventories at the north and south ridgetops indicate minimum regolith residence times of 10.5 ± 3.7 and 9.1 ± 2.9 ky, respectively, similar to residence times inferred from U-series isotopes in Ma et al. (2013). The combination of our results with U-series-derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on SSHO hillcrests. ©2013. American Geophysical Union. All Rights Reserved

    Fluvio-deltaic avulsions during relative sea-level fall.

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    Understanding river response to changes in relative sea level (RSL) is essential for predicting fluvial stratigraphy and source-to-sink dynamics. Recent theoretical work has suggested that rivers can remain aggradational during RSL fall, but field data are needed to verify this response and investigate sediment deposition processes. We show with field work and modeling that fluvio-deltaic systems can remain aggradational or at grade during RSL fall, leading to superelevation and continuation of delta lobe avulsions. The field site is the Goose River, Newfoundland-Labrador, Canada, which has experienced steady RSL fall of around 3–4 mm yr⁻¹ in the past 5 k.y. from post-glacial isostatic rebound. Elevation analysis and optically stimulated luminescence dating suggest that the Goose River avulsed and deposited three delta lobes during RSL fall. Simulation results from Delft3D software show that if the characteristic fluvial response time is longer than the duration of RSL fall, then fluvial systems remain aggradational or at grade, and continue to avulse during RSL fall due to superelevation. Intriguingly, we find that avulsions become more frequent at faster rates of RSL fall, provided the system response time remains longer than the duration of RSL fall. This work suggests that RSL fall rate may influence the architecture of falling-stage or forced regression deposits by controlling the number of deposited delta lobes

    Topological Qubit Design and Leakage

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    We examine how best to design qubits for use in topological quantum computation. These qubits are topological Hilbert spaces associated with small groups of anyons. Op- erations are performed on these by exchanging the anyons. One might argue that, in order to have as many simple single qubit operations as possible, the number of anyons per group should be maximized. However, we show that there is a maximal number of particles per qubit, namely 4, and more generally a maximal number of particles for qudits of dimension d. We also look at the possibility of having topological qubits for which one can perform two-qubit gates without leakage into non-computational states. It turns out that the requirement that all two-qubit gates are leakage free is very restrictive and this property can only be realized for two-qubit systems related to Ising-like anyon models, which do not allow for universal quantum computation by braiding. Our results follow directly from the representation theory of braid groups which means they are valid for all anyon models. We also make some remarks on generalizations to other exchange groups.Comment: 13 pages, 3 figure

    The Green Horizons Scoreboard: indicators on innovation for sustainable development

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    The effect of a goal-setting strategy with integrated feedback on goal attainment in inflammatory arthritis patients:a mixed method study

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    Patients with Inflammatory Arthritis (IA) often experience difficulties in daily life as a result of their disease. Unfortunately, outpatient consultations in daily practice tend to focus on medical topics, thereby ignoring the impact of the disease on patients’ daily lives. Patient-Reported Outcomes (PROs) can be used to understand this impact, but they are not enough for offering person-centered care. Because the patient’s true values and goals can only be ascertained during a proper conversation, which should include both medical as well as patient goals. Therefore, the aim of the study is to evaluate the effect of a goal management strategy with integrated feedback on goal attainment and Health-Related Quality of Life(HRQoL) in IA patients. IA patients with an active disease were given the opportunity to set and follow-up goals. In addition to goal setting, patients were asked to complete online questionnaires on various PROs, including HRQoL. Ninety-two IA patients participated in the study. The mean age was 51 years and most of them had rheumatoid arthritis. A total of 302 patient goals were set, of which 32% were achieved. In the entire population, HRQoL did not change over time, but patients who did not meet their goals tended to report a lower HRQoL. Incorporating a feedback mechanism in a goal-setting strategy has a positive effect on goal attainment. Yet no effect was seen on HRQoL, but this may due to the fact that general HRQoL measurement are not sensitive or specific enough to detect changes that are accompanied with goal setting and attainment.</p

    Performance of continuous glucose monitoring devices during intensive exercise conditions in people with diabetes:the Mont Blanc experience

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    With increasing use of both flash glucose monitoring and real-time continuous glucose monitoring and the reliance of users on these readings, accuracy is important, in particular during intensive exercise. We investigated the performance of the FreeStyle Libre 1 flash glucose monitor and the Guardian Connect EnliteTM real-time continuous glucose monitor by comparing readings with self-monitored blood glucose values during intensive exercise.</p

    Anatomy and growth of a Holocene clinothem in the Gulf of Papua

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    High-resolution seismic profiles and sedimentological data from grab samples and long cores provide an unprecedented picture of the structure, sedimentology, and late Quaternary development of two Gulf of Papua ( GoP) clinothems, one probably Stage 3 and 4 in age and one Holocene in age. The older was partially eroded during Stage 2 and partially covered by the younger clinothem during Stage 1. The younger clinothem consists of three stratigraphic units separated by two surfaces of erosion, bypass, or correlative surfaces of lap. The surfaces were formed by changes in accommodation and sediment supply. The underlying physiography of the older clinothem also appears to play an important role in governing the shape of the younger clinothem. In the northern gulf, oblique clinoforms of the younger clinothem suggest that the rate of sediment supply from the northern rivers outstripped the formation of new accommodation, whereas in the south, sigmoidal clinoforms indicate that accommodation increased faster than sediment supply. The origin of the new accommodation remains uncertain because of limited age constraints. On the basis of sediment thickness, stratal geometry, and acoustic character, off-shelf transport appears to be the dominant sediment transport direction, with preferential accumulation on the promontories and bypass in the valleys. Presently, observed and computed modern flows and complex gyres in shallow water coupled with wave- and current-supported gravity flows or river floods can explain the form, internal clinoform shapes, and mineralogy of the younger Gulf of Papua clinothem

    Determinants of HbA1c reduction with FreeStyle Libre flash glucose monitoring (FLARE-NL 5)

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    Aims: To identify factors predicting HbA1c reduction in patients with diabetes mellitus (DM) using FreeStyle Libre Flash Glucose Monitoring (FSL-FGM). Methods: Data from a 12-month prospective nation-wide FSL registry were used and analysed with multivariable regression. For the present study we included patients with hypoglycaemia unawareness or unexpected hypoglycaemias (n = 566) and persons who did not reach acceptable glycaemic control (HbA1c > 70 mmol/mol (8.5%)) (n = 294). People with other indications for use, such as sensation loss of the fingers or individuals already using FSL-FGM or rtCGM, were excluded (37%). Results: Eight hundred and sixty persons (55% male with a mean age of 46.7 (+/- 16.4) years) were included. Baseline HbA1c was 65.1 (+/- 14.5) mmol/mol (8.1 +/- 1.3%), 75% of the patients had type 1 DM and 37% had microvascular complications. Data concerning HbA1c was present for 482 (56.0%) at 6 months and 423 (49.2%) persons at 12 months. A significant reduction in HbA1c (>= 5 mmol/mol (0.5%)) was present in 187 (22%) persons. For these persons, median HbA1c reduction was -9.0 [-13.0, -4.0] mmol/mol (-0.82 [-1.19, -0.37]%) at 6 months and -9.0 [-15.0, -7.0] mmol/mol (-0.82 [-1.37, -0.64]%) at 12 months. In multi-variable regression analysis with age, gender and SF-12 physical and mental component scores as covariates, only baseline HbA1c was significant: -0.319 (SE 0.025; p <0.001; R-2 = 0.240 for the model). In exploratory analysis among subgroups with different indications for FSL-FGM use (hypoglycaemia unawareness or persistently high HbA1c) and persons with a significant HbA1c decrease over the study period, baseline HbA1c remained the only significant predictor. Conclusions: Among the variables we analysed in the present study, only high HbA1c at baseline predicts significant HbA1c reduction during FSL-CGM use
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