Abrupt climate transition of icy worlds from snowball to moist or runaway greenhouse

Ongoing and future space missions aim to identify potentially habitable planets in our Solar System and beyond. Planetary habitability is determined not only by a planet's current stellar insolation and atmospheric properties, but also by the evolutionary history of its climate. It has been suggested that icy planets and moons become habitable after their initial ice shield melts as their host stars brighten. Here we show from global climate model simulations that a habitable state is not achieved in the climatic evolution of those icy planets and moons that possess an inactive carbonate-silicate cycle and low concentrations of greenhouse gases. Examples for such planetary bodies are the icy moons Europa and Enceladus, and certain icy exoplanets orbiting G and F stars. We find that the stellar fluxes that are required to overcome a planet's initial snowball state are so large that they lead to significant water loss and preclude a habitable planet. Specifically, they exceed the moist greenhouse limit, at which water vapour accumulates at high altitudes where it can readily escape, or the runaway greenhouse limit, at which the strength of the greenhouse increases until the oceans boil away. We suggest that some icy planetary bodies may transition directly to a moist or runaway greenhouse without passing through a habitable Earth-like state.Comment: 31 pages, 4 figures, 2 supplementary tables, and 9 supplementary figure

Sliding mode controller with improved AGA for supercharged boiler drum water level control

ObjectivesIt is difficult to control the drum water level of a supercharged boiler due to the strong load disturbance in the sailing process. In order to ensure the stability of the drum water level, it is necessary to study drum water level control methods under strong load disturbance. To this end, this paper proposes a sliding mode controller with an improved adaptive genetic algorithm (AGA). MethodsThe velocity and accelerated speed of the drum water level error is combined with an S-function to design a sliding mode controller. Its stability is then proven using the Lyapunov stability theorem. On this basis, the sliding mode controller parameters are optimized with the improved AGA. ResultsThe control performance of the sliding mode controller with improved AGA is compared with that of a PID controller. In response to ramp disturbance signals and step disturbance signals, the sliding mode controller with improved AGA can track the input signal without error. Its stability time is 5 s shorter than that of the PID and its overshoot is lower than that of the PID. ConclusionsThe simulation results show that the sliding mode controller with improved AGA is superior to the PID controller

Poly(delta-gluconolactone) and Poly(delta-gluconolactone- ε

Poly(delta-gluconolactone) (PGL) and poly(delta-gluconolactone-ε-caprolactone) (P(GL-CL)) were synthesized through ring-opening polymerization (ROP) and characterized by FT-IR, NMR, XRD, intrinsic viscosity, GPC, DSC, and TGA. The crystallinity of P(GL-CL) with various d-GL/CL ratios (d-GL/CL = 5 : 5, 4 : 6, 3 : 7, 2 : 8, and 1 : 9) was 12.09 to 59.78% while PGL was amorphous. Melting temperature (Tm) of these polymers was 49.8 to 62.0°C and decomposition temperature was 282 to 489°C depending on the d-GL/CL ratios. In addition, all these polymers were degradable and the degradation rates could be controlled by adjusting d-GL/CL ratios. These results indicated that PGL and P(GL-CL) might be promising novel absorbable materials

Numerical analysis for supporting and deformation of complex foundation pit groups in unstable areas of karst strata

Due to the extensive karst development zone in karst areas, the stability of the underground soil layer is poor. The support of foundation pits in this area will be affected by complex environmental factors, and if not handled properly, it will cause significant safety hazards and economic losses. In this paper, the three-dimensional finite element model of the complex foundation pit and adjacent foundation pit group was established with the help of Midas GTS NX numerical software, and numerical simulation was carried out for the whole foundation pit excavation and construction process, and the deformation results of the adjacent foundation pit support structure of the complex foundation pit group and the soil outside the foundation pit were obtained. The results show that the underground wall of the complex foundation pit shifted to the north under the action of buttresses, with a similar “cantilever” displacement pattern on the south side of the underground wall in the center, a “push-back displacement” on the north side of the underground wall in the center, and a “ventral” displacement pattern at the corners of the grounded wall and on the east and west sides. Combined with the field measurement data, the support piles in the internal support system have a “cantilever” displacement pattern under the condition of massive soil unloading in the vicinity of the foundation pit, while the supporting piles show a “parabolic” displacement pattern under the action of the corner internal support. The deformation characteristics of the foundation pit in the presence of adjacent pits are significantly different from the results based on empirical laws. The results of the above study will provide useful technical guidance for the safety of excavation support for foundation pit groups in complex environments and the reasonable control of the surrounding environment

Tolvaptan treatment improves survival of cirrhotic patients with ascites and hyponatremia

Background: Although tolvaptan treatment improves hyponatremia, only few studies have investigated whether tolvaptan actually benefits the survival of cirrhotic patients. This study evaluated the impact of tolvaptan on six-month survival of decompensated cirrhotic patients with and without hyponatremia. Methods: Two hundred forty-nine decompensated cirrhotic patients with or without hyponatremia were enrolled in a multicenter cohort study. Patients were divided into two groups according to receiving either tolvaptan or placebo treatment for 7-day. Subsequently, the patients were followed up for 6 months. Results: Two hundred thirty patients, including 98 with hyponatremia (tolvaptan vs. placebo: 69 vs. 29) finished the study. Tolvaptan did not alter serum sodium levels and survival outcome of decompensated cirrhotic patients without hyponatremia. However, tolvaptan treatment remarkably improved serum sodium levels and six-month survival in patients with hyponatremia. Following tolvaptan treatment, serum sodium levels were restored to normal in 63.8% of patients, whereas in patients receiving placebo, only 36.2% showed the same effect (P < 0.05). Compared to a six-month survival rate of 68.97% in patients receiving placebo, the survival rate in tolvapatan-treated patients was 89.94% (P < 0.05). Furthermore, six-month survival rate in the tolvaptan-treated hyponatremia patients with resolved serum sodium was 81.32%, whereas the survival in those with unresolved serum sodium was only 24% (P < 0.05). Conclusions: Tolvaptan improves short term survival in most decompensated cirrhotic hyponatremia patients with resolved serum sodium. Trials registration: Clinical trial one: ClinicalTrials.gov ID: NCT00664014 , Registered on April 14, 2008. Clinical trial two: ClinicalTrials.gov ID: NCT01349335 , Registered on March 5, 2010. Clinical trial three: ClinicalTrials.gov ID: NCT01349348 , Registered on May 4, 2011

A novel strategy for power sources management in connected plug-in hybrid electric vehicles based on mobile edge computation framework

This paper proposes a novel control framework and the corresponding strategy for power sources management in connected plug-in hybrid electric vehicles (cPHEVs). A mobile edge computation (MEC) based control framework is developed first, evolving the conventional on-board vehicle control unit (VCU) into the hierarchically asynchronous controller that is partly located in cloud. Elaborately contrastive analysis on the performance of processing capacity, communication frequency and communication delay manifests dramatic potential of the proposed framework in sustaining development of the cooperative control strategy for cPHEVs. On the basis of MEC based control framework, a specific cooperative strategy is constructed. The novel strategy accomplishes energy flow management between different power sources with incorporation of the active energy consumption plan and adaptive energy consumption management. The method to generate the reference battery state-of-charge (SOC) trajectories in energy consumption plan stage is emphatically investigated, fast outputting reference trajectories that are tightly close to results by global optimization methods. The estimation of distribution algorithm (EDA) is employed to output reference control policies under the specific terminal conditions assigned via the machine learning based method. Finally, simulation results highlight that the novel strategy attains superior performance in real-time application that is close to the offline global optimization solutions

Development of multilayer Hydroxyapatite - Ag/TiN-Ti coatings deposited by radio frequency magnetron sputtering with potential application in the biomedical field

"NOTICE: this is the author's version of a work that was accepted for publication in Surface and Coatings Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Surface and Coatings Technology, VOL 377, (2019) DOI 10.1016/j.surfcoat.2019.06.097"[EN] The use of composite coatings is emerging as a great alternative to conventional coatings, allowing the combination of different superficial properties that are widely desired in surgical implants, such as osteointegration and bactericidal character, and cannot be provided by one material alone. In the present investigation the effect of the incorporation of a TiN-Ti intermediate bilayer on the chemical composition, structure, morphology, roughness, residual stresses and adhesion of a multi-layer Hydroxyapatite (HA)-Ag coating deposited on Ti-6Al-4V by magnetron sputtering was evaluated. Additionally, the cytotoxicity of the developed system was evaluated by in vitro tests. According to the results obtained, a decrease in the Ca/P ratio from 1.85 to 1.74 was obtained through the deposition of an HA-Ag system on the intermediate bilayer, and the crystallinity of the developed coating was favored. The multi-layer structure was effectively observed by field emission scanning electron microscopy, where it was possible to identify each of the HA, Ag, TiN and Ti layers. Meanwhile, an increase of 7% in crystallite size, a decrease of 36% in residual stresses and an increase of 32% in adhesion were registered for this composite coating compared to the free intermediate bilayer system. Finally, biological evaluation allowed the non-cytotoxic character of the deposited coatings to be confirmed.We thank the University of Antioquia, the Centro de Investigation, Innovation y Desarrollo de materiales (CIDEMAT) group, the Departamento Administrativo de Ciencia, Tecnologia e Innovation (COLCIENCIAS) for financing the Project 15-1696, the scholarship program of Enlazamundos, PR and JLGR acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-1-R (AEI/FEDER, UE) (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Institute de Salud Carlos III with assistance from the European Regional Development Fund.Lenis, J.; Bejarano, G.; Rico Tortosa, PM.; Gómez Ribelles, JL.; Bolívar, F. (2019). Development of multilayer Hydroxyapatite - Ag/TiN-Ti coatings deposited by radio frequency magnetron sputtering with potential application in the biomedical field. Surface and Coatings Technology. 377:1-9. https://doi.org/10.1016/j.surfcoat.2019.06.097S19377Melero, H., Fernández, J., & Guilemany Casadamon, J. M. (2011). Recubrimientos bioactivos: Hidroxiapatita y titania. Biomecánica, 19(1). doi:10.5821/sibb.v19i1.1814Ozeki, K., Yuhta, T., Fukui, Y., & Aoki, H. (2002). Phase composition of sputtered films from a hydroxyapatite target. Surface and Coatings Technology, 160(1), 54-61. doi:10.1016/s0257-8972(02)00363-8Nelea, V., Morosanu, C., Iliescu, M., & Mihailescu, I. N. (2003). 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SIRT1 Functions as an Important Regulator of Estrogen-Mediated Cardiomyocyte Protection in Angiotensin II-Induced Heart Hypertrophy

Background. Sirtuin 1 (SIRT1) is a member of the sirtuin family, which could activate cell survival machinery and has been shown to be protective in regulation of heart function. Here, we determined the mechanism by which SIRT1 regulates Angiotensin II- (AngII-) induced cardiac hypertrophy and injury in vivo and in vitro. Methods. We analyzed SIRT1 expression in the hearts of control and AngII-induced mouse hypertrophy. Female C57BL/6 mice were ovariectomized and pretreated with 17β-estradiol to measure SIRT1 expression. Protein synthesis, cardiomyocyte surface area analysis, qRT-PCR, TUNEL staining, and Western blot were performed on AngII-induced mouse heart hypertrophy samples and cultured neonatal rat ventricular myocytes (NRVMs) to investigate the function of SIRT1. Results. SIRT1 expression was slightly upregulated in AngII-induced mouse heart hypertrophy in vivo and in vitro, accompanied by elevated cardiomyocyte apoptosis. SIRT1 overexpression relieves AngII-induced cardiomyocyte hypertrophy and apoptosis. 17β-Estradiol was able to protect cardiomyocytes from AngII-induced injury with a profound upregulation of SIRT1 and activation of AMPK. Moreover, estrogen receptor inhibitor ICI 182,780 and SIRT1 inhibitor niacinamide could block SIRT1’s protective effect. Conclusions. These results indicate that SIRT1 functions as an important regulator of estrogen-mediated cardiomyocyte protection during AngII-induced heart hypertrophy and injury