683 research outputs found

    Translocation of a polymer chain driven by a dichotomous noise

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    We consider the translocation of a one-dimensional polymer through a pore channel helped by a motor driven by a dichotomous noise with time exponential correlation. We are interested in the study of the translocation time, mean velocity and stall force of the system as a function of the mean driving frequency. We find a monotonous translocation time, in contrast with the mean velocity which shows a pronounced maximum at a given frequency. Interestingly, the stall force shows a nonmonotonic behavior with the presence of a minimum. The influence of the spring elastic constant to the mean translocation times and velocities is also presented.Comment: 11 pages, 7 figure

    Coastal subsidence increases vulnerability to sea level rise over twenty first century in Cartagena, Caribbean Colombia

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    Cartagena is subsiding at a higher rate compared to that of global climate-driven sea level rise. We investigate the relative sea level rise (RSLR) and the influence of vertical land movements in Cartagena through the integration of different datasets, including tide gauge records, GPS geodetic subsidence data, and Interferometric Synthetic Aperture Radar (InSAR) observations of vertical motions. Results reveal a long-term rate (\u3e 60 years) of RSLR of 5.98 ± 0.01 mm/yr. The last two decades exhibited an even greater rate of RSLR of 7.02 ± 0.06 mm/yr. GPS subsidence rates range between − 5.71 ± 2.18 and − 2.85 ± 0.84 mm/yr. InSAR data for the 2014–2020 period show cumulative subsidence rates of up to 72.3 mm. We find that geologically induced vertical motions represent 41% of the observed changes in RSLR and that subsidence poses a major threat to Cartagena’s preservation. The geodetic subsidence rates found would imply a further additional RSLR of 83 mm by 2050 and 225 mm by 2100. The Colombian government should plan for the future and serve as an example to similar cities across the Caribbean

    Coastal subsidence increases vulnerability to sea level rise over twenty first century in Cartagena, Caribbean Colombia

    Get PDF
    Cartagena is subsiding at a higher rate compared to that of global climate-driven sea level rise. We investigate the relative sea level rise (RSLR) and the influence of vertical land movements in Cartagena through the integration of different datasets, including tide gauge records, GPS geodetic subsidence data, and Interferometric Synthetic Aperture Radar (InSAR) observations of vertical motions. Results reveal a long-term rate (\u3e 60 years) of RSLR of 5.98 ± 0.01 mm/yr. The last two decades exhibited an even greater rate of RSLR of 7.02 ± 0.06 mm/yr. GPS subsidence rates range between − 5.71 ± 2.18 and − 2.85 ± 0.84 mm/yr. InSAR data for the 2014–2020 period show cumulative subsidence rates of up to 72.3 mm. We find that geologically induced vertical motions represent 41% of the observed changes in RSLR and that subsidence poses a major threat to Cartagena’s preservation. The geodetic subsidence rates found would imply a further additional RSLR of 83 mm by 2050 and 225 mm by 2100. The Colombian government should plan for the future and serve as an example to similar cities across the Caribbean

    Towards smart open dynamic fleets

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-33509-4_32Nowadays, vehicles of modern fleets are endowed with advanced devices that allow the operators of a control center to have global knowledge about fleet status, including existing incidents. Fleet management systems support real-time decision making at the control center so as to maximize fleet perform‐ ance. In this paper, setting out from our experience in dynamic coordination of fleet management systems, we focus on fleets that are open, dynamic and highly autonomous. Furthermore, we propose how to cope with the scalability problem as the number of vehicles grows. We present our proposed architecture for open fleet management systems and use the case of taxi services as example of our proposal.Work partially supported by Spanish Government through the projects iHAS (grant TIN2012-36586-C03) and SURF (grant TIN2015-65515-C4-X-R), the Autonomous Region of Madrid through grant S2013/ICE-3019 (“MOSI-AGIL-CM”, cofunded by EU Structural Funds FSE and FEDER) and URJC-Santander (30VCPIGI15).Billhardt, H.; Fernández, A.; Lujak, M.; Ossowski, S.; Julian Inglada, VJ.; Paz, JFD.; Hernández, JZ. (2016). Towards smart open dynamic fleets. En Multi-Agent Systems and Agreement Technologies. Springer. 410-424. https://doi.org/10.1007/978-3-319-33509-4_32S41042

    Sleep-disordered breathing, circulating exosomes, and insulin sensitivity in adipocytes

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    Background: Sleep-disordered-breathing (SDB), which is characterized by chronic intermittent hypoxia (IH) and sleep fragmentation (SF), is a prevalent condition that promotes metabolic dysfunction, particularly among patients suffering from obstructive hypoventilation syndrome (OHS). Exosomes are generated ubiquitously, are readily present in the circulation, and their cargo may exert substantial functional cellular alterations in both physiological and pathological conditions. However, the effects of plasma exosomes on adipocyte metabolism in patients with OHS or in mice subjected to IH or SF mimicking SDB are unclear. Methods: Exosomes from fasting morning plasma samples from obese adults with polysomnographically-confirmed OSA before and after 3 months of adherent CPAP therapy were assayed. In addition, C57BL/6 mice were randomly assigned to (1) sleep control (SC), (2) sleep fragmentation (SF), and (3) intermittent hypoxia (HI) for 6 weeks, and plasma exosomes were isolated. Equivalent exosome amounts were added to differentiated adipocytes in culture, after which insulin sensitivity was assessed using 0 nM and 5 nM insulin-induced pAKT/AKT expression changes by western blotting. Results: When plasma exosomes were co-cultured and internalized by human naive adipocytes, significant reductions emerged in Akt phosphorylation responses to insulin when compared to exosomes obtained after 24 months of adherent CPAP treatment (n = 24; p < 0.001), while no such changes occur in untreated patients (n = 8). In addition, OHS exosomes induced significant increases in adipocyte lipolysis that were attenuated after CPAP, but did not alter pre-adipocyte differentiation. Similarly, exosomes from SF- and IH-exposed mice induced attenuated p-AKT/total AKT responses to exogenous insulin and increased glycerol content in naive murine adipocytes, without altering pre-adipocyte differentiation. Conclusions: Using in vitro adipocyte-based functional reporter assays, alterations in plasma exosomal cargo occur in SDB, and appear to contribute to adipocyte metabolic dysfunction. Further exploration of exosomal miRNA signatures in either human subjects or animal models and their putative organ and cell targets appears warranted

    Agricultural intensification can help protect the Amazon Forest and reduce global warming / Protecting the Amazon forest and reducing global warming via agricultural intensification

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    The Amazon basin includes 550 M ha covered with rainforests, with 60% of this area being in Brazil. Conversion of rainforest for soybean production raises concerns about the degree to which Brazil can reconcile production and environmental goals. Here we investigated the degree to which intensification could help Brazil produce more soybean without further encroachment of the Amazon Forest. Our analysis shows that continuation of current trends in soybean yield and area would lead to conversion of additional 5.7 M ha of forests and savannas during the next 15 years, with an associated 2550 Mt of CO2eq released into the atmosphere. In contrast, acceleration of yield improvement, coupled with expansion of soybean area only in areas currently used for livestock production, would allow Brazil to achieve similar economic benefits without deforestation and with substantially lower global climate warming

    The impact of the Val158Met COMT polymorphism on context processing in patients on the schizophrenia spectrum and their relatives

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    Introduction: The level of dopamine in the prefrontal cortex (PFC) appears to play a fundamental role in cognitive alterations in schizophrenia. The Val158Met polymorphism of the catechol-O-methyltransferase (COMT) enzyme impacts dopamine availability in the prefrontal cortex and can thus influence cognitive functioning. Among the different cognitive deficits found in schizophrenia patients, context processing deficits have been noted as a specific characteristic of schizophrenia, for which the cerebral substrate appears to be located in the dorsolateral PFC. In this study, we examine the impact of the Val158Met COMT polymorphism on context processing in a sample of patients on the schizophrenia spectrum, their relatives, and healthy control subjects evaluated using the Dot Probe Expectancy Task (DPX). Methods: Forty patients on the schizophrenia spectrum, 26 relatives, and 63 healthy control subjects were genotyped and performed the DPX test. Results: Both patients and their relatives demonstrated deficits in context processing influenced by the Val158Met COMT polymorphism. Compared with the other subjects, the Val/Val subjects showed poorer performance on context processing tasks. Conclusions: Deficits in context processing in schizophrenic patients and their families are influenced by the Val158Met COMT functional polymorphism, likely as a consequence of reduced dopamine availability in the PFC

    Resolving spin currents and spin densities generated by charge-spin interconversion in systems with reduced crystal symmetry

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    The ability to control the generation of spins in arbitrary directions is a long-sought goal in spintronics. Charge to spin interconversion (CSI) phenomena depend strongly on symmetry. Systems with reduced crystal symmetry allow anisotropic CSI with unconventional components, where charge and spin currents and the spin polarization are not mutually perpendicular to each other. Here, we demonstrate experimentally that the CSI in graphene-WTe induces spins with components in all three spatial directions. By performing multi-terminal nonlocal spin precession experiments, with specific magnetic fields orientations, we discuss how to disentangle the CSI from the spin Hall and inverse spin galvanic effects.We acknowledge support of the European Union's Horizon 2020 FET-PROACTIVE project TOCHA under Grant No. 824140 and of the Spanish Research Agency (AEI), Ministry of Science and Innovation, under Contracts No. PID2019-111773RB-I00/AEI/10.13039/501100011033, and SEV-2017-0706 Severo Ochoa. J F S acknowledges support from AEIunder contract RYC2019-028368-I/AEI/10.13039/50110001103, W S T and M V C from the European Union Horizon 2020 research and innovation program, Grant No. 881603 (Graphene Flagship), and I F A of a fellowship from 'la Caixa' Foundation (ID 100010434) with code LCF/BQ/DI18/11660030 and of H2020 Marie Skłodowska-Curie Grant No. 713673. J S acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 754558
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