Low-Complexity Non-uniform Constellation Demapping Algorithm for Broadcasting System

This paper presents a novel low-complexity soft demapping algorithm for  two-dimensional non-uniform spaced constellations (2D-NUCs) and massive order one-dimensional NUCs (1D-NUCs). NUCs have been implemented in a wide range of new broadcasting systems to approach the Shannon limit further, such as DVB-NGH, ATSC 3.0 and NGB-W. However, the soft demapping complexity is extreme due to the substantial distance calculations. In the proposed scheme, the demapping process is classified into four cases based on different quadrants. To deal with the complexity problem, four groups of reduced subsets in terms of the quadrant for each bit are separately calculated and stored in advance. Analysis and simulation prove that the proposed demapper only introduces a small penalty under 0.02dB with respect to Max-Log-MAP demapper, whereas a significant complexity reduction ranging from 68.75\% to 88.54\% is obtained

A sustainability assessment of five major food crops' water footprints in China from 1978 to 2010

Rice, wheat, corn, soybeans, and sorghum are the five major crops in China, which account for 92% of the country's total grain production and 33% of its water consumption. Combining water footprint analysis tools with sustainability assessment tools, the water sustainability of the five major crops can be analyzed. Based on ecological economics theory, this paper constructs a sustainability evaluation system of China's five major crops' water footprints and analyzes the national and provincial diversity of the sustainability of the five major crops' water footprints using three dimensions: scale, distribution, and equity. We find that the interprovincial distribution equity sustainability divergence is the key bottleneck factor that restricts sustainability (more than scale and configuration). One key strategy is to arrange grain production at the national level, on the basis of considering the differences of water-resource endowment between different provinces to break through the bottleneck of the water-resource distribution sustainability of these five major food crops. This paper determines a general management model that can improve the sustainability of water resource management at the interprovincial level by comparing and analyzing the most sustainable and least sustainable provinces for the water footprint production of these five major crops

Bone remodeling at microscrew interface near extraction site in the beagle dog mandible-histologic and immunohistochemical analyses

Extraction is often used as part of orthodontic therapy, and good control of anchorage is a key step after extraction. Although microscrews can be implanted close to the extraction site in order to achieve orthodontic support, the efficiency of bone remodeling at the implant-bone interface near the extraction region is dubious. OBJECTIVE: The purpose of this study was to investigate bone remodeling of the bone-microscrew interface near the tooth extraction site, in the absence of loading. MATERIAL AND METHODS: Third and fourth premolars were extracted from the mandibles of beagle dogs, followed by placement of test microscrews near the extraction sites. Control microscrews were placed further away from the extraction site. All samples were collected after 1, 3, 8, or 12 weeks of healing following extraction. The bone remodeling process at the interface was evaluated using histologic and immunohistochemical analyses. RESULTS: Initially, a large number of inflammatory cells were aggregated at the interface. The expression levels of core binding factor (Cbfa1), osteocalcin (OC) and transforming growth factor beta (TGF-β) were inconspicuous in both groups, whereas tumor necrosis factor alpha (TNF-α) was strongly expressed, especially in the test groups (

Impacts of Drought on Maize and Soybean Production in Northeast China During the Past Five Decades.

Climate change has a distinct impact on agriculture in China, particularly in the northeast, a key agriculture area sensitive to extreme hydroclimate events. Using monthly climate and agriculture data, the influence of drought on maize and soybean yields-two of the main crops in the region-in northeast China since 1961 to 2017 were investigated. The results showed that the temperature in the growing season increased by 1.0 °C from the period 1998-2017 to the period 1961-1980, while the annual precipitation decreased slightly. However, precipitation trends varied throughout the growing season (May-September), increasing slightly in May and June, but decreasing in July, August and September, associated with the weakening of the East Asian summer monsoon. Consequently, the annual and growing season drought frequency increased by 15%, and 25%, respectively, in the period 1998-2017 relative to the period 1961-1980. The highest drought frequency (55%) was observed in September. At the same time, the drought intensity during the growing season increased by 7.8%. The increasing frequency and intensity of drought had negative influences on the two crops. During moderate drought years in the period 1961-2017, 3.2% and 10.4% of the provincial maize and soybean yields were lost, respectively. However, during more severe drought years, losses doubled for soybean (21.8%), but increased more than four-fold for maize (14.0%). Moreover, in comparison to the period 1961-1980, a higher proportion of the yields were lost in the period 1998-2017, particularly for maize, which increased by 15% (increase for soybean was 2.4%). This change largely depends on increasing droughts in August and September, when both crops are in their filling stages. The impact of drought on maize and soybean production was different during different growth stages, where a strong relationship was noted between drought and yield loss of soybean in its filling stage. Given the sensitivity of maize and soybean yields in northeast China to drought, and the observed production trends, climate change will likely have significant negative impacts on productivity in the future

Response of temperate forest ecosystem services to rainfall: A case study in the forest nature reserves of northern China

In the context of global climate change, temperate forests in climate-sensitive areas are inevitably affected. To deepen the understanding of the impact on precipitation changes into the relationship between key ecosystem services (ESs), this study selected net primary productivity (NPP), soil conservation (SC) and water yield (WY) of temperate forest in northern China as objects, and the Spearman correlation test and redundancy analysis were applied to analyze the response of ESs relationship to precipitation gradient. The results show that precipitation is the meteorological factor with the greatest impact (contribution 21.2%, p<0.01) on ESs and their relationships in temperate forests. The 600-700 mm precipitation gradient is the key turning point in the change of ESs relationship of WY with NPP and SC. This indicates that attention should be paid to the spatial variation of the 600-700 mm precipitation region in the future warm-wet in northern China, which should be used as a dividing line of forest management and policy development. Based on the results, future restoration projects in northern temperate forest should focus on (1) in areas with less than 600-700 mm of precipitation, attention should be paid to the selection of tree species for afforestation to maintain regional water balance; (2) in areas with more than 700 mm of precipitation, soil and water conservation projects need to be planned, especially in mountainous area. The research can not only support the management of temperate forest ecosystems in northern China, but also provide reference to other forest ecosystems to cope with climate change

The efficacy of different training programs guided by cardiopulmonary exercise test goals for the treatment of male patients with chronic obstructive pulmonary disease

To explore the therapeutic effect of aerobic exercise nursing plans based on target heart rate in cardiopulmonary exercise tests on male patients with chronic obstructive pulmonary disease. This study recruited 90 male patients with chronic obstructive pulmonary disease who met specific screening criteria and were evenly divided into a control group and an experimental group based on a random number table. The control group received respiratory training based on the target heart rate in the cardiopulmonary exercise test, while the experimental group received aerobic exercise based on the target heart rate in the cardiopulmonary exercise test. Both groups received 12 weeks of exercise each. Cardiopulmonary function tests showed that peak oxygen consumption (peak VO2), anaerobic threshold (AT), forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), and the FEV1/FVC ratio in the test group were significantly higher than those in the control group (p < 0.05); furthermore, the carbon dioxide ventilation equivalent (VE/VCO2) slope was significantly lower than that in the control group (p < 0.05). The 6MWT of the test group was significantly higher than that in the control group (p < 0.05). The CAT score, Borg score and scores related to the symptoms, activities, and impacts related to quality-of-life were significantly reduced after intervention (p < 0.05). Aerobic exercise based on cardiopulmonary exercise testing can improve the health status, quality of life and prognosis of COPD patients

Are Pangolins Scapegoats of the COVID-19 Outbreak-CoV Transmission and Pathology Evidence?

The COVID‐19 outbreak has infected over 6 million people across the world. The origin of COVID‐19 coronavirus (CoV) remains unknown, although pangolins have been suggested as potential hosts. We investigated two pangolins seized in Guangdong Province, China. Molecular screening revealed CoV in one pangolin (“Dahu”), while another (“Meidong”) was infected by Ehrlichia ruminantium. Dahu exhibited difficulty breathing, infections of lung, intestines, and nostrils, as revealed by computed tomography imaging and necropsy. Previous phylogenetic analyses showed bat coronavirus RaTG13 is closer to COVID‐19 CoV compared to pangolin coronavirus. Over 20 caregivers have had close physical contact with CoV‐positive Dahu, but none became infected with CoV. Our data suggest that pangolins are unlikely the natural reservoir or secondary hosts of COVID‐19 CoV. Pangolins seems to be victims infected by CoV carried by a not yet unidentified natural reservoir host species, perhaps due to their weakened immune system

Pronounced and unavoidable impacts of low-end global warming on northern high-latitude land ecosystems

Arctic ecosystems are particularly vulnerable to climate change because of Arctic amplification. Here, we assessed the climatic impacts of low-end, 1.5 °C, and 2.0 °C global temperature increases above pre-industrial levels, on the warming of terrestrial ecosystems in northern high latitudes (NHL, above 60 °N including pan-Arctic tundra and boreal forests) under the framework of the Inter-Sectoral Impact Model Intercomparison Project phase 2b protocol. We analyzed the simulated changes of net primary productivity, vegetation biomass, and soil carbon stocks of eight ecosystem models that were forced by the projections of four global climate models and two atmospheric greenhouse gas pathways (RCP2.6 and RCP6.0). Our results showed that considerable impacts on ecosystem carbon budgets, particularly primary productivity and vegetation biomass, are very likely to occur in the NHL areas. The models agreed on increases in primary productivity and biomass accumulation, despite considerable inter-model and inter-scenario differences in the magnitudes of the responses. The inter-model variability highlighted the inadequacies of the present models, which fail to consider important components such as permafrost and wildfire. The simulated impacts were attributable primarily to the rapid temperature increases in the NHL and the greater sensitivity of northern vegetation to warming, which contrasted with the less pronounced responses of soil carbon stocks. The simulated increases of vegetation biomass by 30–60 Pg C in this century have implications for climate policy such as the Paris Agreement. Comparison between the results at two warming levels showed the effectiveness of emission reductions in ameliorating the impacts and revealed unavoidable impacts for which adaptation options are urgently needed in the NHL ecosystems