286 research outputs found

    Analysis and Design of Shaxian Snack Catering Management Information System

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    This paper first expounds the background, purpose and significance of the research on Shaxian snack catering system. Moreover?the daily business process and data flow of Shaxian snacks are analyzed in various aspects to improve the design thought. Combined with functional analysis, background code and pages can be made easily. Finally, the system is tested and the system logic is found. The actual data are used for data statistics, and the last step is modifying and improving. Then the interface of the catering system was made and the design of the catering system was implemented and developed. Finally, the completed restaurant system was tested, the system was tested for deficiencies, and the missing places were modified

    Quantification and scenario analysis of CO2 emissions from the central heating supply system in China from 2006 to 2025

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    Policies associated with the central heating supply system affect the livelihoods of people in China. With the extensive consumption of energy for central heating, large quantities of CO2 emissions are produced each year. Coal-fired heating boiler plants are the primary source of emissions; however, thermal power plants are becoming much more prevalent, and gas-fired heating boiler plants remain uncommon. This study quantified the amount of CO2 emitted from the central heating supply system in China using a mass balance method with updated emission factors from the IPCC. Emissions increased from 189.04 Tg to 319.39 Tg between 2006 and 2015. From a spatial perspective, regions with larger central heating areas, durations and coverages produced more CO2 emissions. The central heating method depends on the level of electric power consumption, policies and regulations, and resource reserves at the local scale. Compared with the use of only coal-fired heating boiler plants to provide central heating, using thermal power plants and gas-fired heating boiler plants reduced CO2 emissions by 98.19 Tg in 2015 in China. A comparison of the CO2 emissions under various central heating scenarios showed that emissions will be 520.97 Tg, 308.79 Tg and 191.86 Tg for business as usual, positive and optimal scenarios through 2025, respectively. China has acknowledged the considerable potential for reducing central heating and will make efforts to pursue improved heating strategies in the future

    Water table fluctuations and carbon accumulation of a fen and a bog in the James Bay Lowlands of Quebec, Canada

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    An important work regarding northern hemisphere peatland modeling is currently being processed. One of the first steps of this work is to understand the relationship between different components of the peatland system and to analyse the way unspecific peatland systems react to water table fluctuations in terms of accumulation and decomposition that we present in this article. We chose distinct sampling sites within a large region including boreal and subarctic ecosystems in the Bay James lowlands, northern Québec, Canada. Two fens were selected in the subarctic region and two bogs in the boreal region. These sites have different geographical, climatological and ecological features (ex. pH, nutrient availability and species compositions). Fens and bogs behaviours in matter of decomposition and accumulation thus follow different patterns. The analyses of cores for theses sites allow the comparison and the quantification of the differences between subarctic and boreal sites. Five cores were analysed against Testate amoebae every 2cm for the short cores and every 4cm for the long core. These cores are also dated with 210 Pb and 14C. Loss on ignition analysis was performed with the resolution of 1cm for each core. The use of a transfer function with the results of the Testate amoebae analysis allowed reconstruction of water table fluctuations from 7500 years BP to the present. This reconstruction gives us an insight into the humidity regime of the system. This information is compared to the carbon accumulation sequences to evaluate the response of the system to changes in water table position. This research shows response range between sites and quantifies the range of the water table fluctuation inducing an imbalance of the system. This information will be of significant importance for the development of the peatland dynamics modeling

    Global Priority Conservation Areas in the Face of 21st Century Climate Change

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    In an era when global biodiversity is increasingly impacted by rapidly changing climate, efforts to conserve global biodiversity may be compromised if we do not consider the uneven distribution of climate-induced threats. Here, via a novel application of an aggregate Regional Climate Change Index (RCCI) that combines changes in mean annual temperature and precipitation with changes in their interannual variability, we assess multi-dimensional climate changes across the “Global 200” ecoregions – a set of priority ecoregions designed to “achieve the goal of saving a broad diversity of the Earth’s ecosystems” – over the 21st century. Using an ensemble of 62 climate scenarios, our analyses show that, between 1991–2010 and 2081–2100, 96% of the ecoregions considered will be likely (more than 66% probability) to face moderate-to-pronounced climate changes, when compared to the magnitudes of change during the past five decades. Ecoregions at high northern latitudes are projected to experience most pronounced climate change, followed by those in the Mediterranean Basin, Amazon Basin, East Africa, and South Asia. Relatively modest RCCI signals are expected over ecoregions in Northwest South America, West Africa, and Southeast Asia, yet with considerable uncertainties. Although not indicative of climate-change impacts per se, the RCCI-based assessment can help policy-makers gain a quantitative and comprehensive overview of the unevenly distributed climate risks across the G200 ecoregions. Whether due to significant climate change signals or large uncertainties, the ecoregions highlighted in the assessment deserve special attention in more detailed impact assessments to inform effective conservation strategies under future climate change.This study was supported by the Environmental Protection Public Service Project of China (201209031) (URL:http://kjs.mep.gov.cn/gyxhykyzx/)

    Nitrogen addition mediates the response of foliar stoichiometry to phosphorus addition: a meta-analysis

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    Background Changes in foliar nitrogen (N) and phosphorus (P) stoichiometry play important roles in predicting the effects of global change on ecosystem structure and function. However, there is substantial debate on the effects of P addition on foliar N and P stoichiometry, particularly under different levels of N addition. Thus, we conducted a global meta-analysis to investigate how N addition alters the effects of P addition on foliar N and P stoichiometry across different rates and durations of P addition and plant growth types based on more than 1150 observations. Results We found that P addition without N addition increased foliar N concentrations, whereas P addition with N addition had no effect. The positive effects of P addition on foliar P concentrations were greater without N addition than with N addition. Additionally, the effects of P addition on foliar N, P and N:P ratios varied with the rate and duration of P addition. In particular, short-term or low-dose P addition with and without N addition increased foliar N concentration, and the positive effects of short-term or low-dose P addition on foliar P concentrations were greater without N addition than with N addition. The responses of foliar N and P stoichiometry of evergreen plants to P addition were greater without N addition than with N addition. Moreover, regardless of N addition, soil P availability was more effective than P resorption efficiency in predicting the changes in foliar N and P stoichiometry in response to P addition. Conclusions Our results highlight that increasing N deposition might alter the response of foliar N and P stoichiometry to P addition and demonstrate the important effect of the experimental environment on the results. These results advance our understanding of the response of plant nutrient use efficiency to P addition with increasing N deposition

    Contrasting Soil Bacterial Community, Diversity, and Function in Two Forests in China

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    Bacteria are the highest abundant microorganisms in the soil. To investigate bacteria community structures, diversity, and functions, contrasting them in four different seasons all the year round with/within two different forest type soils of China. We analyzed soil bacterial community based on 16S rRNA gene sequencing via Illumina HiSeq platform at a temperate deciduous broad-leaved forest (Baotianman, BTM) and a tropical rainforest (Jianfengling, JFL). We obtained 51,137 operational taxonomic units (OTUs) and classified them into 44 phyla and 556 known genera, 18.2% of which had a relative abundance >1%. The composition in each phylum was similar between the two forest sites. Proteobacteria and Acidobacteria were the most abundant phyla in the soil samples between the two forest sites. The Shannon index did not significantly differ among the four seasons at BTM or JFL and was higher at BTM than JFL in each season. The bacteria community at both BTM and JFL showed two significant (P < 0.05) predicted functions related to carbon cycle (anoxygenic photoautotrophy sulfur oxidizing and anoxygenic photoautotrophy) and three significant (P < 0.05) predicted functions related to nitrogen cycle (nitrous denitrificaton, nitrite denitrification, and nitrous oxide denitrification). We provide the basis on how changes in bacterial community composition and diversity leading to differences in carbon and nitrogen cycles at the two forests
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