17,768 research outputs found

    The impact of memory effect on space fractional strong quantum couplers with tunable decay behavior and its numerical simulation

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    The nontrivial behavior of wave packets in the space fractional coupled nonlinear Schrödinger equation has received considerable theoretical attention. The difficulty comes from the fact that the Riesz fractional derivative is inherently a prehistorical operator. In contrast, nonlinear Schrödinger equation with both time and space nonlocal operators, which is the cornerstone in the modeling of a new type of fractional quantum couplers, is still in high demand of attention. This paper is devoted to numerically study the propagation of solitons through a new type of quantum couplers which can be called time-space fractional quantum couplers. The numerical methodology is based on the finite-difference/Galerkin Legendre spectral method with an easy to implement numerical algorithm. The time-fractional derivative is considered to describe the decay behavior and the nonlocal memory of the model. We conduct numerical simulations to observe the performance of the tunable decay and the sharpness behavior of the time-space fractional strongly coupled nonlinear Schrödinger model as well as the performance of the numerical algorithm. Numerical simulations show that the time and space fractional-order operators control the decay behavior or the memory and the sharpness of the interface and undergo a seamless transition of the fractional-order parameters

    Performance of the new seedless grape "BRS Isis" grown in subtropical area.

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    "BRS Isis" is a new colored seedless table grape tolerant to downy mildew, the main vine disease in subtropical humid areas. This new seedless cultivar is an interspecific hybrid from the crossing of CNPUV 681?29 [Arkansas 1976 X CNPUV 147?3 ("Niagara Branca" x "Venus")] x "BRS Linda", and was recently released by Embrapa Grape and Wine, Brazil. The performance of ?BRS Isis? seedless grape was evaluated in an experimental vineyard in 2016 located in a subtropical area at Marialva city, state of Parana, Brazil. The vines were grafted onto "IAC 766 Campinas" rootstock and trained in an overhead trellising system spaced at 2 × 5 m. Vines were cane-pruning in late winter of July 2016, and for assessments, 20 representative vines were selected in the area. As ?BRS Isis? is a very fruitful grape, presenting 4 bunches per shoot, a load adjustment was performed after fruitset removing 50% of bunches per shoot, leaving 2 bunches per shoot, equivalent to a density of 10 bunches.m − 2 . The duration in days of the main phenological stages from pruning to harvest, and the physicochemical and yield characteristics of ?BRS Isis? seedless grape were subjected to evaluation. It was determined that the cycle is 144 days. The means of berry and bunch weight was 6 . 7 ± 1 . 0 g and 500 . 0 ± 0 . 04 g, respectively, and the color index of berries (CIRG) was 4.3 ± 1.3. The means of total soluble solids (TSS), titratable acidity (TA) and maturity index (TSS/TA) observed were 14.2 ± 0.3 ◦ Brix, 0.6 ± 0.04% of tartaric acid and 24 . 1 ± 1 . 5, espectively, while the yield was 49.0 ± 5.7 tons.ha − 1 . The yield observed is considered high to keep a sustainable crop over time, thus, in order to obtain grapes of ?BRS Isis? with regular yield, and possibly, with a higher content of soluble solids, it is desirable to keep only 1 bunch per shoot (5 bunches.m − 2 ) after fruitset.Também publicado em: WORLD VINE AND WINE CONGRESS, 40

    Prevalence and correlates of depressive disorders in people with Type 2 diabetes: results from the International Prevalence and Treatment of Diabetes and Depression (INTERPRET‐DD) study, a collaborative study carried out in 14 countries

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    Aims To assess the prevalence and management of depressive disorders in people with Type 2 diabetes in different countries. Methods People with diabetes aged 18–65 years and treated in outpatient settings were recruited in 14 countries and underwent a psychiatric interview. Participants completed the Patient Health Questionnaire and the Problem Areas in Diabetes scale. Demographic and medical record data were collected. Results A total of 2783 people with Type 2 diabetes (45.3% men, mean duration of diabetes 8.8 years) participated. Overall, 10.6% were diagnosed with current major depressive disorder and 17.0% reported moderate to severe levels of depressive symptomatology (Patient Health Questionnaire scores >9). Multivariable analyses showed that, after controlling for country, current major depressive disorder was significantly associated with gender (women) (PPPPP<0.0001). The proportion of those with either current major depressive disorder or moderate to severe levels of depressive symptomatology who had a diagnosis or any treatment for their depression recorded in their medical records was extremely low and non-existent in many countries (0–29.6%). Conclusions Our international study, the largest of this type ever undertaken, shows that people with diabetes frequently have depressive disorders and also significant levels of depressive symptoms. Our findings indicate that the identification and appropriate care for psychological and psychiatric problems is not the norm and suggest a lack of the comprehensive approach to diabetes management that is needed to improve clinical outcomes

    A critical look at studies applying over-sampling on the TPEHGDB dataset

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    Preterm birth is the leading cause of death among young children and has a large prevalence globally. Machine learning models, based on features extracted from clinical sources such as electronic patient files, yield promising results. In this study, we review similar studies that constructed predictive models based on a publicly available dataset, called the Term-Preterm EHG Database (TPEHGDB), which contains electrohysterogram signals on top of clinical data. These studies often report near-perfect prediction results, by applying over-sampling as a means of data augmentation. We reconstruct these results to show that they can only be achieved when data augmentation is applied on the entire dataset prior to partitioning into training and testing set. This results in (i) samples that are highly correlated to data points from the test set are introduced and added to the training set, and (ii) artificial samples that are highly correlated to points from the training set being added to the test set. Many previously reported results therefore carry little meaning in terms of the actual effectiveness of the model in making predictions on unseen data in a real-world setting. After focusing on the danger of applying over-sampling strategies before data partitioning, we present a realistic baseline for the TPEHGDB dataset and show how the predictive performance and clinical use can be improved by incorporating features from electrohysterogram sensors and by applying over-sampling on the training set

    Resonance triplet dynamics in the quenched unitary Bose gas

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    The quenched unitary Bose gas is a paradigmatic example of a strongly interacting out-of-equilibrium quantum system, whose dynamics become difficult to describe theoretically due to the growth of non-Gaussian quantum correlations. We develop a conserving many-body theory capable of capturing these effects, allowing us to model the post-quench dynamics in previously inaccessible time regimes. By comparing our results directly to experiment, we answer long-standing fundamental questions regarding the heating and population dynamics in the gas, specifically highlighting the dominance of strong lossless correlations rather than incoherent atomic losses. Our general framework, which reframes the dynamics of unitary quantum systems in terms of explicit connections to microscopic physics, can be broadly applied to any quantum system containing strong few-body correlations.Comment: 7 pages, 4 figure

    Emergent inflation of the Efimov spectrum under three-body spin-exchange interactions

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    One of the most fascinating predictions of few-body quantum physics is the Efimov effect, a universal accumulation of an infinite geometric series of three-body bound states at a two-body scattering resonance. Ever since the first experimental observation of such an Efimov state, the precise characterization of their physical properties has continued to challenge few-body theory. This is demonstrated most strongly by the lithium few-body puzzle, a remarkable theoretical discrepancy with the observed Efimov spectrum in 7Li^7 \text{Li}. Here, we resolve this long-standing puzzle, demonstrating that the discrepancy arises out of the presence of strong non-universal three-body spin-exchange interactions. This conclusion is obtained from a thorough numerical solution of the quantum mechanical three-body problem, including precise interatomic interactions and all spin degrees of freedom for three alkali-metal atoms. Our results show excellent agreement with the experimental data regarding both the Efimov spectrum and the absolute rate constants of three-body recombination, and in addition reveal a general product propensity for such triatomic reactions in the Paschen-Back regime, stemming from Wigner's spin conservation rule.Comment: 7+5 pages, 3+2 figure

    Efimovian three-body potential from broad to narrow Feshbach resonances

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    We analyse the change in the hyperradial Efimovian three-body potential as the two-body interaction is tuned from the broad to narrow Feshbach resonance regime. Here, it is known from both theory and experiment that the three-body dissociation scattering length aa_- shifts away from the universal value of 9.7 rvdW-9.7 \ r_{\mathrm{vdW}}, with rvdW=12(mC6/2)1/4r_{\mathrm{vdW}} = \frac{1}{2} \left(m C_6/\hbar^2 \right)^{1/4} the two-body van der Waals range. We model the three-body system using a separable two-body interaction that takes into account the full zero-energy behaviour of the multichannel wave function. We find that the short-range repulsive barrier in the three-body potential characteristic for single-channel models remains universal for narrow resonances, whilst the change in the three-body parameter originates from a strong decrease in the potential depth. From an analysis of the underlying spin structure we further attribute this behavior to the dominance of the two-body interaction in the resonant channel compared to other background interactions.Comment: 12 pages, 11 figure
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