18,681 research outputs found

    A review of physical supply and EROI of fossil fuels in China

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    This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year (or 9.6 EJ/year), in 2018; its total gas production will peak at around 350 Bcm/year (or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year (or 91.9 EJ/year) around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI (energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found

    2-Diazoacetoacetic acid, an efficient and convenient reagent for the synthesis of alpha-diazo-beta-ketoesters

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    The formation of various alpha-diazo acetoacetic esters can be obtained in a single transformation with good to excellent yields using readily available 2-diazoacetoacetic acid

    Newspaper of the university of alaska southeast juneau campus

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    Victors named in student election -- Students 'dig in' to mining -- Student government allocates fall budget -- Faculty prepares for U.S-U.S.S.R course -- New library furnishings delay opening -- Spring Dean's list announced -- Home cooking ... Rugg aims to please -- Apply now for legislative internship -- Dee Swavely bowls 209 in tournament -- LETTER -- PRESIDENT'S MESSAGE -- Perseverance "Odessey" a trip -- Taiwanese teachers study English at UAS -- Morgan: Academics 1st, Athletics second -- BRIEFLY -- UNCLASSIFIEDS -- Fall enrollment rises, Juneau up 15 percen

    Maternal cell phone use in early pregnancy and child's language, communication and motor skills at 3 and 5 years: the Norwegian mother and child cohort study (MoBa)

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    BACKGROUND: Cell phone use during pregnancy is a public health concern. We investigated the association between maternal cell phone use in pregnancy and child's language, communication and motor skills at 3 and 5 years. METHODS: This prospective study includes 45,389 mother-child pairs, participants of the MoBa, recruited at mid-pregnancy from 1999 to 2008. Maternal frequency of cell phone use in early pregnancy and child language, communication and motor skills at 3 and 5 years, were assessed by questionnaires. Logistic regression was used to estimate the associations. RESULTS: No cell phone use in early pregnancy was reported by 9.8% of women, while 39%, 46.9% and 4.3% of the women were categorized as low, medium and high cell phone users. Children of cell phone user mothers had 17% (OR = 0.83, 95% CI: 0.77, 0.89) lower adjusted risk of having low sentence complexity at 3 years, compared to children of non-users. The risk was 13%, 22% and 29% lower by low, medium and high maternal cell phone use. Additionally, children of cell phone users had lower risk of low motor skills score at 3 years, compared to children of non-users, but this association was not found at 5 years. We found no association between maternal cell phone use and low communication skills. CONCLUSIONS: We reported a decreased risk of low language and motor skills at three years in relation to prenatal cell phone use, which might be explained by enhanced maternal-child interaction among cell phone users. No evidence of adverse neurodevelopmental effects of prenatal cell phone use was reported

    Exploiting Full-Waveform Lidar Data and Multiresolution Wavelet Analysis for Vertical Object Detection and Recognition

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    A current challenge in performing airport obstruction surveys using airborne lidar is lack of reliable, automated methods for extracting and attributing vertical objects from the lidar data. This paper presents a new approach to solving this problem, taking advantage of the additional data provided byfull-waveform systems. The procedure entails first deconvolving and georeferencing the lidar waveformdata to create dense, detailed point clouds in which the vertical structure of objects, such as trees, towers, and buildings, is well characterized. The point clouds are then voxelized to produce high-resolution volumes of lidar intensity values, and a 3D wavelet decomposition is computed. Verticalobject detection and recognition is performed in the wavelet domain using a multiresolution template matching approach. The method was tested using lidar waveform data and ground truth collected for project areas in Madison,Wisconsin. Preliminary results demonstrate the potential of the approach

    Combining pot, atom and step economy (PASE) in organic synthesis. Synthesis of tetrahydropyran-4-ones

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    The combination of pot, atom and step economy (PASE) in the synthesis of organic molecules of medium complexity can lead to a significant 'greening' of a synthetic route. This is demonstrated by the synthesis of highly substituted tetrahydropyran-4-ones and is quantified by a series of recognised metrics, which demonstrate the efficiency of combining PASE over conventional synthetic strategies

    JCV-specific T-cells producing IFN-gamma are differently associated with PmL occurrence in HIV patients and liver transplant recipients

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    Aim of this work was to investigate a possible correlation between the frequency of JCV-specific T-cells and PML occurrence in HIV-infected subjects and in liver transplant recipients. A significant decrease of JCV-specific T-cells was observed in HIV-PML subjects, highlighting a close relation between JCV-specific T-cell immune impairment and PML occurrence in HIV-subjects. Interestingly, liver-transplant recipients (LTR) showed a low frequency of JCV-specific T-cells, similar to HIV-PML subjects. Nevertheless, none of the enrolled LTR developed PML, suggesting the existence of different immunological mechanisms involved in the maintenance of a protective immune response in LT

    Kanamycin resistance during in vitro development of pollen from transgenic tomato plants

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    Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes. Kanamycin, however, severely affected tube growth of pollen from non-transformed plants, while pollen from plants containing the chimaeric gene were less sensitive and produced significantly longer tubes at kanamycin concentrations between 200-400 mg l-1. Apparently, this resistance for kanamycin correlates with the expression of the chimaeric gene during male gametophytic development.
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