247 research outputs found

    City-level water withdrawal in China:Accounting methodology and applications

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    In the context of the freshwater crisis, accounting for water withdrawal could help planners better regulate water use in different sectors to combat water scarcity. However, the water withdrawal statistics in China are patchy, and the water data across all sectors at the city level appear to be relatively insufficient. Hence, we develop a general framework to, for the first time, estimate the water withdrawal of 58 economic–social–environmental sectors in cities in China. This methodology was applied because only inconsistent water statistics collected from different data sources at the city level are available. We applied it to 18 representative Chinese cities. Different from conventional perceptions that agriculture is usually the largest water user, industrial and household water withdrawal may also occupy the largest percentages in the water-use structure of some cities. The discrepancy among annual household water use per capita in the urban areas of different cities is relatively small (as is the case for rural areas), but that between urban and rural areas is large. As a result, increased attention should be paid to controlling industrial and urban household water use in particular cities. China should specifically prepare annual water accounts at the city level and establish a timetable to tackle water scarcity, which is a basic step toward efficient and sustainable water crisis mitigation

    Triolein-based polycation lipid nanocarrier for efficient gene delivery: characteristics and mechanism

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    We proposed to develop a polycation lipid nanocarrier (PLN) with higher transfection efficiency than our previously described polycation nanostrucutred lipid nanocarrier (PNLC). PLN was composed of triolein, cetylated low-molecular-weight polyethylenimine, and dioleoyl phosphatidylethanolamine. The physicochemical properties of PLN and the PLN/DNA complexes (PDC) were characterized. The in vitro transfection was performed in human lung adenocarcinoma (SPC-A1) cells, and the intracellular mechanism was investigated as well. The measurements indicated that PLN and PDC are homogenous nanometer-sized particles with a positive charge. The transfection efficiency of PDC significantly increased with the content of triolein and was higher than that of PNLC and commercial Lipofectamine™ 2000. In particular, the transfection of PLN in the presence of 10% serum was more effective than that in its absence. With the help of specific inhibitors of chlorpromazine and filipin, the clathrin-dependent endocytosis pathway was determined to be the main contributor to the successful transfection mediated by PLN in SPC-A1 cells. The captured images verified that the fluorescent PDC was localized in the lysosomes and nuclei after endocytosis. Thus, PLN represents a novel efficient nonviral gene delivery vector

    Urban waterlogging prediction and risk analysis based on rainfall time series features: A case study of Shenzhen

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    In recent years, the frequency of extreme weather has increased, and urban waterlogging caused by sudden rainfall has occurred from time to time. With the development of urbanization, a large amount of land has been developed and the proportion of impervious area has increased, intensifying the risk of urban waterlogging. How to use the available meteorological data for accurate prediction and early warning of waterlogging hazards has become a key issue in the field of disaster prevention and risk assessment. In this paper, based on historical meteorological data, we combine domain knowledge and model parameters to experimentally extract rainfall time series related features for future waterlogging depth prediction. A novel waterlogging depth prediction model that applies only rainfall data as input is proposed by machine learning algorithms. By analyzing a large amount of historical flooding monitoring data, a “rainfall-waterlogging amplification factor” based on the geographical features of monitoring stations is constructed to quantify the mapping relationship between rainfall and waterlogging depths at different locations. After the model is trained and corrected by the measured data, the prediction error for short-time rainfall basically reaches within 2 cm. This method improves prediction performance by a factor of 2.5–3 over featureless time series methods. It effectively overcomes the limitations of small coverage of monitoring stations and insufficient historical waterlogging data, and can achieve more accurate short-term waterlogging prediction. At the same time, it can provide reference suggestions for the government to conduct waterlogging risk analysis and add new sensor stations by counting the amplification factor of other locations

    DETERMINISTIC DEPLOYMENT for DIRECTIONAL SENSOR NODES

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    Porezni sustav Republike Hrvatske se sastoji od više poreznih oblika koji se primjenjuju po različitim poreznim stopama na različite vrste poreznih osnovica. Porez na dobit je jedan od tih oblika i ima značajnu ulogu u poreznom sustavu. Obzirom da se porez na dobit primjenjuje na ostvareno dobit iz gospodarske djelatnost, njegova stopa i primjena utječe na događanja u gospodarstvu i jedan je od najčešćih poreza kod kojih se pojavljuje porezna evazija. Kako postojeći zakoni ne stimuliraju reinvestiranje dobiti poduzeća, često se kod poduzetnika pronalaze različiti načini izbjegavanja plaćanja ovog poreza, kroz donacije, stipendije ili kroz ulaganja u obrtna sredstva poduzeća. Porez na dobit ima i ulogu u privlačenju investicija u gospodarstvo, pa je zbog toga jako bitno po kojoj stopi se ovaj porez obračunava i na koji način se plaća. Kako bi se privukle investicije, bilo domaće bilo inozemne, bitno je što konkurentnije odrediti poreznu stopu i poreznu osnovicu za primjenu ovog poreza. Republika Hrvatska se izvjestan vremanski period nalazi u gospodarskoj krizi, a izlazak iz nje i pokretanje gospodarstva se traži u stranim investicijama. Obzirom da je gospodarstvo Republike Hrvatske otvoreno i nalazi se na globalnom tržištu, države u okruženju su mu konkurencija. U ovom radu će se analizirati stope poreza na dobit u nekim zemljama članicama Europske Unije, ali i zemalja koje to nisu, ali su izravna konkurencija Republici Hrvatskoj u privlačenju inozemnih investicija

    Propagation Analysis of 2.4 GHz Wireless Sensor Network Signal in a Plantation

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    Wireless sensor network is a popular technology on information acquisition and processing, which has been widely used in plantation ecological monitoring domain. The plantation environments, including antenna height-gain, depolarization, terrain, humidity and many factors have great influences on the propagation of 2.4GHz wireless sensor network radio frequency signal. In this paper, a complete research for propagation law of 2.4GHz wireless sensor network signal in plantation environment is presented, with using regression of support vector machines based on experimental data. A single variable prediction model is established on field strength of wireless sensor network signal in plantation environment, thus compares it with the original experience prediction model and measured data. The establishment of aforesaid model provides an important theoretical support for determining the max effective communication range of wireless sensor node and the nodes' rational distribution. It will certainly promote the application of wireless sensor network in plantation ecological monitoring field

    Effects of L-cysteine on the freeze-drying survival rate of Lactiplantibacillus plantarum LIP-1

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    Amino acids are often used as probiotic growth factors. Their addition to the growth medium is found to effectively enhance the resistance of the strain to adverse environments. In this research, we found that adding 0.05 g/L L-cysteine to culture medium improved the freeze-drying survival rate of the strain. We investigated the internal mechanism behind this phenomenon and found that the addition of L-cysteine can reduce DNA damage to bacterial cells during the freeze-drying process. In comparison to the control group without L-cysteine, the treatment group with the addition of 0.05 g/L of L-cysteine exhibited an up-regulation of the metC gene, leading to the metabolism of L-cysteine into pyruvate and NH3, which raised the intracellular pH, reduced DNA damage, and consequently enhanced the resistance of Lactiplantibacillus plantarum LIP-1 to freeze-drying
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