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In Proof-of-Stake (PoS) blockchain network, stakeholders spend tokens for consumption while competing for network transaction fee with unspent tokens. Stakeholders are incentivized to form staking pools to compete with each other, but continued staking pool merge does not occur given fixed pool operating cost. Unlike other blockchain networks and traditional payment systems, token price in PoS blockchain network is a direct result of competition among service providers (staking pools) and is strongly positively correlated with network decentralization level. As an extension, we show that uneven wealth distribution or biased validator selection function enhances stake centralization and sabotage token price. [ABSTRACT FROM AUTHOR]

Recent improvements in remote sensing technologies have boosted building detection techniques from rough classifications using moderate resolution imagery to precise extraction from high-resolution imagery. Shadows frequently emerge in high-resolution urban images. To exploit shadow information, we developed a novel building detection and classification algorithm for images of urban areas with large-size shadows, employing only the visible spectral bands to determine the height levels of buildings. The proposed method, building general-classified by height (BGCH), calculates shadow orientation, detects buildings using seed-blocks, and classifies the buildings into different height groups. Our proposed approach was tested on complex urban scenes from Toronto and Beijing. The experimental results illustrate that our proposed method accurately and efficiently detects and classifies buildings by their height levels; the building detection rate exceeded 95%. The precision of classification by height levels was over 90%. This novel building-height-level detection method provides rich information at low cost and is suitable for further city scene analysis, flood disaster risk assessment, population estimation, and building change detection applications. [ABSTRACT FROM AUTHOR]

Compacted loess is a special collapsible unsaturated soil and is sensitive to hydraulic conditions. Understanding and modeling the coupled hydromechanical behavior of compacted loess during isotropic compression is essential for establishing a complete constitutive model for unsaturated soils, which is of significance for predicting the deformation of loess fills in engineering. In this research, a series of constant suction isotropic compression tests are conducted to study the behavior of compacted loess. The experimental results show that volume change and soil–water characteristics are mutually affected during compression and that the normal compression curves flatten out and shift downward with the decrease in suction. Based on the experimental observations, the normal compression surface is modified, and the loading–collapse yield curve is deduced for the compacted loess. An equation associated with the void ratio is used to describe the effect of the volume change on the soil–water characteristics. Furthermore, a coupled hydromechanical constitutive model for the compacted loess under isotropic compression conditions is proposed within the framework of the Barcelona basic model. Model predictions of the mechanical and hydraulic behaviors of the compacted loess for constant suction isotropic compression tests and wetting tests at constant net stresses are compared with experimental data to verify the performance and validation of the proposed model. The comparisons indicate that the proposed model can accurately reproduce the coupled hydromechanical behavior of the compacted loess under isotropic compression conditions. [ABSTRACT FROM AUTHOR]

(1) Background: Acute myocardial infarction (AMI) imposes a great burden on global health. Few studies have demonstrated the effects of valley concentration of air pollutants on AMI hospital admissions. (2) Methods: Hospitalizations for AMI from 1 May 2014 to 31 December 2019 were analyzed. Generalized additive models (GAM) were used to quantify the exposure–response association between the hourly peak, mean, and valley concentration of six air pollutants and AMI hospital admissions. Stratification analyses were conducted to identify the susceptible population. (3) Results: Hourly peak, mean, and valley concentrations of PM2.5, PM10, SO2, NO2, and CO were significantly associated with AMI hospital admissions. Each 10-unit increase in the hourly valley concentration of them led to 0.50% (0.35–0.66%), 0.44 % (0.32–0.56%), 0.84% (0.47–1.22%), 1.86% (0.73–3.01%), and 44.6% (28.99–62.10%) excess risk in AMI hospital admissions, respectively. In addition, the effects of hourly valley concentration were larger than mean and peak concentrations. The effects in the female or older than 65 groups were larger than that in the male or younger than 65 groups. (4) Conclusions: PM2.5, PM10, SO2, NO2, and CO exposure contributed to increased AMI hospital admissions. Hourly valley concentration might be a more potent indicator of adverse cardiovascular events. Females and individuals older than 65 were more susceptible to ambient air pollutant exposure. [ABSTRACT FROM AUTHOR]

Aims: We aimed to assess the association between serum 25-hydroxyvitamin D (25(OH)D) levels with all-cause and cardiovascular mortality in patients with nonalcoholic fatty liver disease (NAFLD). Methods: We performed a retrospective cohort study based on the US National Health and Nutrition Examination Survey 2001–2016 on adults aged ≥20 years. NAFLD was determined as a US Fatty Liver Index score ≥ 30 in the absence of other liver conditions. Weighted Cox proportional hazards regression models were applied to explore the relationship between serum 25(OH)D levels and mortality. Results: 898 all-cause deaths and 305 cardiovascular deaths were recorded over a median follow-up of 8.7 years. Compared with those in the severe deficiency group (below 25.0 nmol/L), the fully adjusted HRs and 95% CIs of NAFLD patients with sufficient serum 25(OH)D concentrations (≥75.0 nmol/L) were 0.36 (0.22, 0.60) for all-cause mortality and 0.14 (0.07, 0.29) for cardiovascular mortality. Each one-unit increase in the natural log-transformed serum 25(OH)D concentration was related to a 41% lower risk for all-cause deaths (HR = 0.59, 95% CI: 0.46, 0.77) and a 65% lower risk for cardiovascular deaths (HR = 0.35, 95% CI: 0.22, 0.58). Conclusions: Among NAFLD patients, increased serum 25(OH)D levels were independently associated with reduced risk for all-cause and cardiovascular deaths. [ABSTRACT FROM AUTHOR]

Purpose: Asthma has a major impact on patients' quality of life, mortality, and healthcare burden. Some evidence suggests that environmental factors may trigger asthma. However, there has been limited research on the relationship between air pressure and asthma hospital admissions, especially in China. Thus, we aimed to study the influence of air pressure and identify potentially susceptible populations. Methods: The study data were gathered from hospitalization records with a primary diagnosis of asthma from all secondary and tertiary hospitals in Beijing from January 1, 2013, to December 31, 2016. The study examined the association between the risk of asthma and air pressure using a distributed lag non-linear model (DLNM). We also performed a stratified analysis to identify the susceptible populations. Results: A total of 23,697 asthma hospital admissions were included in the study. We found that the relative risk (RR) and the 7-day cumulative relative risk (CRR) of asthma had an approximate negative correlation with air pressure. At the same time, we found that the association was most apparent on the day of exposure (lag = 0). Conclusion: Ambient air pressure had an approximately negative correlation with daily asthma hospital admissions in Beijing, China. That means the risk of hospital admission for asthma would be increased by low air pressure. Furthermore, air pressure has a significant effect on asthma only on the day of exposure. It is possibly significant to protect the vulnerable on days with low air pressure, especially those younger than 65 years. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) is an important arrhythmia associated with cardiovascular morbidity and mortality. This study is focused on exploring the potential relationship between short‐term air pollution exposure and occurrence of AF. Methods: A case‐crossover design was used to investigate the effect of pollutants on AF occurrence among 100 patients from 2013 to 2014. The air pollutants included ambient particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5), particulate matter less than 10 μm in aerodynamic diameter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3). Participants with cardiac implantable electronic devices implanted were followed‐up to December 31, 2014. Results: A 10 μg/m3 increase of PM2.5 and PM10 was associated with 3.8% (95% confidence interval [CI]: 1.4–6.2) and 2.7% (95% CI: 0.6–4.8) increase in the risk of AF occurrence, respectively. No statistically significant association was noted with SO2, NO2, CO, and O3. Conclusions: Short‐term exposure to particular matter, both PM2.5 and PM10, is associated with an increased risk of AF. This further demonstrates the urgency for air quality monitoring and control in geographical area with intense pollution. [ABSTRACT FROM AUTHOR]

Over the past few decades, a growing body of epidemiological studies found the effects of temperature on cardiovascular disease, including the risk for acute myocardial infarction (AMI). Our study aimed to investigate whether there is an association between extremely temperature and acute myocardial infarction hospital admission in Beijng, China. We obtained 81029 AMI cases and daily temperature data from January 1, 2013 to December 31, 2016. We employed a time series design and modeled distributed lag nonlinear model (DLNM) to analyze effects of temperature on daily AMI cases. Compared with the 10th percentile temperature measured by daily mean temperature (Tmean), daily minimum temperature (Tmin) and daily minimum apparent temperature (ATmin), the cumulative relative risks (CRR) at 1st percentile of Tmean, Tmin and ATmin for AMI hospitalization were 1.15(95% CI: 1.02, 1.30), 1.24(95% CI: 1.11, 1.38) and 1.41(95% CI: 1.18, 1.68), respectively. Moderate low temperature (10th vs 25th) also had adverse impact on AMI events. The susceptive groups were males and people 65 years and older. No associations were found between high temperature and AMI risk. The main limitation of the study is temperature exposure was not individualized. These findings on cold-associated AMI hospitalization helps characterize the public health burden of cold and target interventions to reduce temperature induced AMI occurrence. [ABSTRACT FROM AUTHOR]

Background: The study aimed to analyze the hospital charges of the inpatients with acute ischemic stroke in Beijing and determine the factors associated with hospital costs. Methods: Medical records of hospitalized patients with a primary diagnosis of ischemic stroke according to International Classification of Diseases 10th Revision codes were collected from 121 hospitals in Beijing from March 1, 2012, to February 28, 2015. Distribution characteristics of hospital charges for different hospital levels (level 2 hospitals and level 3 hospitals) and types (Western medicine hospitals and Chinese medicine hospitals) were studied. Linear regression analysis was used to examine the association among hospital costs and factors that influenced total hospital charges. Results: There were 158,781 admissions for ischemic stroke, 63.1% of the patients were male and their mean age was 67.7 ± 12.4 years, the median length of hospital stay (LOHS) was 13.5 days (interquartile range 9.9–18.1 days). The median hospital charge was 2,112 (1,436–3,147) US dollars. Of these, 46.7% were for medicine, 21.1% for laboratory and examination, and 16.3% for therapy. LOHS, hospital level, and pulmonary infection were key determinants of the hospital charges. Conclusions: The proportion of medicine fees for the ischemic stroke inpatients showed a downward trend during the period from 2012 to 2015, but medicine fees still accounted for the largest percentage of hospital charges in China. LOHS emerged to be the main determinant of the cost. Decreasing medicine fees and LOHS might be strategies to decrease hospital charges and reduce economic burden of stroke in China. [ABSTRACT FROM AUTHOR]

Background: The findings of prospective cohort studies are inconsistent regarding the association between dietary magnesium intake and serum magnesium concentration and the risk of hypertension. We aimed to review the evidence from prospective cohort studies and perform a dose-response meta-analysis to investigate the relationship between dietary magnesium intake and serum magnesium concentrations and the risk of hypertension.Methods: We searched systematically PubMed, EMBASE and the Cochrane Library databases from October 1951 through June 2016. Prospective cohort studies reporting effect estimates with 95% confidence intervals (CIs) for hypertension in more than two categories of dietary magnesium intake and/or serum magnesium concentrations were included. Random-effects models were used to combine the estimated effects.Results: Nine articles (six on dietary magnesium intake, two on serum magnesium concentration and one on both) of ten cohort studies, including 20,119 cases of hypertension and 180,566 participates, were eligible for inclusion in the meta-analysis. We found an inverse association between dietary magnesium intake and the risk of hypertension [relative risk (RR) = 0.92; 95% CI: 0.86, 0.98] comparing the highest intake group with the lowest. A 100 mg/day increment in magnesium intake was associated with a 5% reduction in the risk of hypertension (RR = 0.95; 95% CI: 0.90, 1.00). The association of serum magnesium concentration with the risk of hypertension was marginally significant (RR = 0.91; 95% CI: 0.80, 1.02).Conclusions: Current evidence supports the inverse dose-response relationship between dietary magnesium intake and the risk of hypertension. However, the evidence about the relationship between serum magnesium concentration and hypertension is limited. [ABSTRACT FROM AUTHOR]

Introduction: Bed rest has been considered as the cornerstone of management of deep vein thrombosis (DVT) for a long time, though it is not evidence-base, and there is growing evidence favoring early ambulation. Methods: Electronic databases including Medline, PubMed, Cochrane Library and three Chinese databases were searched with key words of “deep vein thrombosis”, “pulmonary embolism”, “venous thrombosis”, “bed rest”, “immobilization”, “mobilization” and “ambulation”. We considered randomized controlled trials, prospective or retrospective cohort studies that compared the outcomes of acute DVT patients managed with early ambulation versus bed rest, in addition to standard anticoagulation. Meta-analysis pertaining to the incidence of new pulmonary embolism (PE), progression of DVT, and DVT related deaths were conducted, as well as the extent of remission of pain and edema. Results: 13 studies were included with a total of 3269 patients. Compared to bed rest, early ambulation was not associated with a higher incidence of new PE, progression of DVT, or DVT related deaths (RD −0.03, 95% CI −0.05∼ −0.02; Z = 1.24, p = 0.22; random effect model, Tau2 = 0.01). Moreover, if the patients suffered moderate or severe pain initially, early ambulation was related to a better outcome, with respect to remission of acute pain in the affected limb (SMD 0.42, 95%CI 0.09∼0.74; Z = 2.52, p = 0.01; random effect model, Tau2 = 0.04). Meta-analysis of alleviation of edema cannot elicit a solid conclusion because of significant heterogeneity among the few studies. Conclusions: Compared to bed rest, early ambulation of acute DVT patients with anticoagulation was not associated with a higher incidence of new PE, progression of DVT, and DVT related deaths. Furthermore, for the patients suffered moderate or severe pain initially, a better outcome can be seen in early ambulation group, regarding to the remission of acute pain in the affected limb. [ABSTRACT FROM AUTHOR]