40 research outputs found

    Mechanics of Isolated Horizons in Scalar-Tensor Theories

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    Based on the first-order action for scalar-tensor theories with the Immirzi parameter, the symplectic form for the spacetimes admitting a weakly isolated horizon as internal boundary is derived by the covariant phase space approach. The first law of thermodynamics for the weakly isolated horizons with rotational symmetry is obtained. It turns out that the Immirzi parameter appears in the expression of the angular momentum of isolated horizon, and the scalar field contributes to the horizon entropy.Comment: 7 page

    The thermodynamics of isolated horizons in loop quantum gravity

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    The statistical mechanical calculation of the thermodynamical properties of non-rotating isolated horizons are studied in the loop quantum gravity framework. By employing the Hawking temperature and horizon mass of isolated horizons as physical inputs, the microcanonical ensemble associated with the system are well established. As a result, the black hole entropy and other thermodynamical quantities can be computed and consistent with well-known Hawking's semiclassical analysis. Moreover, the value of the Immirzi parameter of loop quantum gravity for {higher dimensional case and 4-dimensional U(1) case are} also obtained.Comment: 9 pages, 1 figure;V2, 12 pages, U(1) group case in 4 dimensions is included, figure update

    Investigation of hydrate slurry flow behaviors in deep-sea pipes with different inclination angles

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    The marine area is the main direction of the development of oil and gas resources in the world. The pipeline transportation technology of natural gas hydrate slurry plays an important role in the exploitation of marine oil and gas and the exploitation of marine gas hydrate resources. In order to study the influence of pipe inclination on pipeline transportation, population balance model based on hydrate particle aggregation dynamics was coupled with the Eulerianā€“Eulerian two-fluid multiphase flow model to simulate the flow behaviors of hydrate slurry flow in pipes with different inclination angles. In the study, three variables of inclination, flow rate and initial particle size were considered. The results show that tilted pipes are beneficial to hydrate slurry transport rather than harmful. Meanwhile, higher flow rates and lower initial particle sizes are beneficial for promoting the flow safety of hydrate slurry transport. However, the flow pressure drop of the hydrate slurry increases with the increase of the flow rate and the decrease of the initial particle size, which is not conducive to the economics of mining. The research results in this paper can provide reference for the research of hydrate slurry flow safety and parameter guidance for hydrate solid fluidized mining

    Associations of sugar-sweetened beverages intake frequency with physical growth and glucolipid metabolism among children and adolescents

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    BackgroundChildren and adolescents drink sugar-sweetened beverages (SSBs) frequently. Research has confirmed that SSBs associate with weight gain and overweight or obesity. However, it is unclear whether high SSBs intake associates with abnormal changes in physical growth and glucolipid metabolism before causing adverse health outcomes such as overweight and obesity. Early identification of associated health risks of overconsumption of SSBs have important public health implications. ObjectiveTo investigate the differences in physical growth and glucolipid metabolism between different SSBs intake frequency groups in normal weight children and adolescents aged 6-17 years, and to evaluate the early effects of SSBs intake on physical growth and glycolipid metabolism before causing overweight and obesity, aiming to provide a scientific basis for the prevention and control of childhood overweight and obesity and related chronic diseases, and for the formulation of policies on the control of SSBs consumption. MethodsData were from the Shanghai Diet and Health Survey (SDHS) among primary and secondary school students. The participants were normal weight children and adolescents aged 6-17 years. Propensity scores were calculated according to energy intake and physical activity factors, after stratifying by age and gender. Participants were 1:1 matched with the closest propensity scores in the high-frequency (ā‰„1 timeĀ·dāˆ’1) and the low-frequency (ā‰¤1 timeĀ·weekāˆ’1) SSBs intake groups. The outcome indicators were physical measurements such as height, weight, percent of body fat, and waist circumference, and metabolic indicators such as fasting blood glucose, total triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Body mass index (BMI) was calculated. Food frequency questionnaire was used to collect SSBs consumption in the past three months through face-to-face interview. A paired t-test was used to compare the differences in physical and glycolipid metabolic indicators between the high-frequency intake group and the low-frequency intake group of SSBs. ResultsA total of 431 pairs were obtained. For children and adolescents in grades 6-9, overall height (difference=2.92 cm, P=0.002), weight (difference=2.53 kg, P=0.003), and waist circumference (difference=1.34 cm, P=0.035) were higher in those who consumed SSBs ā‰„1 timeĀ·dāˆ’1 than in those who consumed ā‰¤1 timeĀ·weekāˆ’1. For children and adolescents in grades 10-12, overall weight (difference=2.27 kg, P=0.041) was higher in those who consumed SSBs ā‰„1 timeĀ·dāˆ’1 than in those who consumed ā‰¤1 timeĀ·weekāˆ’1. Over 95% of the study subjects reported blood glucose and lipid test results within the normal range; but girls in grades 1-5 who consumed SSBs ā‰„1 timeĀ·dāˆ’1 had a higher total cholesterol (difference=0.20 mmolĀ·Lāˆ’1, P=0.027) and low-density lipoprotein cholesterol (difference=0.19 mmolĀ·Lāˆ’1, P=0.010) than those who consumed ā‰¤1 timeĀ·weekāˆ’1; boys in grades 6-9 who consumed SSBs ā‰„1 timeĀ·dāˆ’1 had a lower high-density lipoprotein cholesterol (difference=-0.10 mmolĀ·Lāˆ’1, P=0.039) than those who consumed ā‰¤1 timeĀ·weekāˆ’1. ConclusionHigh-frequency intake of SSBs may be associated with higher total cholesterol and low-density lipoprotein cholesterol in normal weight children and adolescents in grades 1-5, and higher weight in normal weight children and adolescents in grades 6-12. There is an urgent need to educate children and adolescents about nutritional health, enhance their ability to make healthy food and beverage choices, and take early interventions to control the intake of SSBs in children

    Salmon Calcitonin Exerts an Antidepressant Effect by Activating Amylin Receptors

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    Depressive disorder is defined as a psychiatric disease characterized by the core symptoms of anhedonia and learned helplessness. Currently, the treatment of depression still calls for medications with high effectiveness, rapid action, and few side effects, although many drugs, including fluoxetine and ketamine, have been approved for clinical usage by the Food and Drug Administration (FDA). In this study, we focused on calcitonin as an amylin receptor polypeptide, of which the antidepressant effect has not been reported, even if calcitonin gene-related peptides have been previously demonstrated to improve depressive-like behaviors in rodents. Here, the antidepressant potential of salmon calcitonin (sCT) was first evaluated in a chronic restraint stress (CRS) mouse model of depression. We observed that the immobility duration in CRS mice was significantly increased during the tail suspension test and forced swimming test. Furthermore, a single administration of sCT was found to successfully rescue depressive-like behaviors in CRS mice. Lastly, AC187 as a potent amylin receptor antagonist was applied to investigate the roles of amylin receptors in depression. We found that AC187 significantly eliminated the antidepressant effects of sCT. Taken together, our data revealed that sCT could ameliorate a depressive-like phenotype probably via the amylin signaling pathway. sCT should be considered as a potential therapeutic candidate for depressive disorder in the future

    Fuzzy Logic in Surveillance Big Video Data Analysis: Comprehensive Review, Challenges, and Research Directions

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    CCTV cameras installed for continuous surveillance generate enormous amounts of data daily, forging the term ā€œBig Video Dataā€ (BVD). The active practice of BVD includes intelligent surveillance and activity recognition, among other challenging tasks. To efficiently address these tasks, the computer vision research community has provided monitoring systems, activity recognition methods, and many other computationally complex solutions for the purposeful usage of BVD. Unfortunately, the limited capabilities of these methods, higher computational complexity, and stringent installation requirements hinder their practical implementation in real-world scenarios, which still demand human operators sitting in front of cameras to monitor activities or make actionable decisions based on BVD. The usage of human-like logic, known as fuzzy logic, has been employed emerging for various data science applications such as control systems, image processing, decision making, routing, and advanced safety-critical systems. This is due to its ability to handle various sources of real world domain and data uncertainties, generating easily adaptable and explainable data-based models. Fuzzy logic can be effectively used for surveillance as a complementary for huge-sized artificial intelligence models and tiresome training procedures. In this paper, we draw researchersā€™ attention towards the usage of fuzzy logic for surveillance in the context of BVD. We carry out a comprehensive literature survey of methods for vision sensory data analytics that resort to fuzzy logic concepts. Our overview highlights the advantages, downsides, and challenges in existing video analysis methods based on fuzzy logic for surveillance applications. We enumerate and discuss the datasets used by these methods, and finally provide an outlook towards future research directions derived from our critical assessment of the efforts invested so far in this exciting field
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