2,604 research outputs found

    Fossil fuel prices and the economic and budgetary challenges of a small energy-importing economy : the case of Portugal

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    This paper examines the economic and budgetary impacts of fuel prices using a dynamic general equilibrium model of the Portuguese economy which high- lights the mechanisms of endogenous growth and includes a detailed modeling of the public sector. The fuel price scenarios are based on forecasts by the US Department of Energy (DOE-US) and the International Energy Agency (IEA-OECD) and represent a wide range of projections for absolute and relative fossil fuel prices. In terms of the long term economic impact, our results suggest a 1.9 % drop in GDP in the DOE-US scenario and 1.6 % in the IEA-OECD scenario. As to the budgetary impact, higher fuel prices lead to lower tax revenues, which, coupled with a reduction in public spending, translate into lower public deficits. Accordingly, increasing fuel prices create an important policy trade off in that they can contribute to reducing the public deficit while hindering economic growth. We find that fairly strong incentives for wind energy can reduce the economic impact of fuel prices by 14.2 % in the DOE-US price scenario and 18.5 % reduction in the IEA-OECD price scenario. Finally, our results highlight the importance of public sector spending decisions and the mechanisms of endogenous growth in understanding the impact of fossil fuel prices. Indeed, a scenario of higher fuel prices would, with exogenous public decisions and exogenous economic growth assumptions, result in substantially smaller economic effects and yield adverse budgetary effects.info:eu-repo/semantics/publishedVersio

    Status of cosmic-ray antideuteron searches

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    The precise measurement of cosmic-ray antiparticles serves as important means for identifying the nature of dark matter. Recent years showed that identifying the nature of dark matter with cosmic-ray positrons and higher energy antiprotons is difficult, and has lead to a significantly increased interest in cosmic-ray antideuteron searches. Antideuterons may also be generated in dark matter annihilations or decays, offering a potential breakthrough in unexplored phase space for dark matter. Low-energy antideuterons are an important approach because the flux from dark matter interactions exceeds the background flux by more than two orders of magnitude in the low-energy range for a wide variety of models. This review is based on the "dbar14 - dedicated cosmic-ray antideuteron workshop", which brought together theorists and experimentalists in the field to discuss the current status, perspectives, and challenges for cosmic-ray antideuteron searches and discusses the motivation for antideuteron searches, the theoretical and experimental uncertainties of antideuteron production and propagation in our Galaxy, as well as give an experimental cosmic-ray antideuteron search status update. This report is a condensed summary of the article "Review of the theoretical and experimental status of dark matter identification with cosmic-ray antideuteron" (arXiv:1505.07785).Comment: 9 pages, 4 figures, ICRC 2015 proceeding

    Ozonolysis of a-phellandrene - Part 2 : Compositional analysis of secondary organic aerosol highlights the role of stabilized Criegee intermediates

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    The molecular composition of secondary organic aerosol (SOA) generated from the ozonolysis of α-phellandrene is investigated for the first time using high pressure liquid chromatography coupled to high-resolution Quadrupole-Orbitrap tandem mass spectrometry. In total, 21 prominent products or isomeric product groups were identified using both positive and negative ionisation modes, with potential formation mechanisms discussed. The aerosol was found to be composed primarily of polyfunctional first- and second-generation species containing one or more carbonyl, acid, alcohol and hydroperoxide functionalities, with the products significantly more complex than those proposed from basic gas-phase chemistry in the companion paper (Mackenzie-Rae et al., 2017a). Mass spectra show a large number of dimeric products are also formed. Both direct scavenging evidence using formic acid, and indirect evidence from double bond equivalency factors, suggests the dominant oligomerisation mechanism is the bimolecular reaction of stabilised Criegee intermediates (SCIs) with non-radical ozonolysis products. Saturation vapour concentration estimates suggest monomeric species cannot explain the rapid nucleation burst of fresh aerosol observed in chamber experiments, hence dimeric species are believed to be responsible for new particle formation, with detected first- and second-generation products driving further particle growth in the system. Ultimately, identification of the major constituents and formation pathways of α-phellandrene SOA leads to a greater understanding of the atmospheric processes and implications of monoterpene emissions and SCIs, especially around Eucalypt forests regions where α-phellandrene is primarily emitted

    T-box transcription factor Brachyury is associated with prostate cancer progression and aggressiveness

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    Purpose: Successful therapy of patients with prostate cancer is highly dependent on reliable diagnostic and prognostic biomarkers. Brachyury is considered a negative prognostic factor in colon and lung cancer; however, there are no reports on Brachyury’s expression in prostate cancer. Experimental Design: In this study, we aimed to assess the impact of Brachyury expression in prostate tumorigenesis using a large series of human prostate samples comprising benign tissue, prostate intraepithelial neoplasia (PIN) lesions, localized tumor, and metastatic tissues. The results obtained were compared with what can be inferred from the Oncomine database. In addition, multiple in vitro models of prostate cancer were used to dissect the biologic role of Brachyury in prostate cancer progression. Results: We found that Brachyury is significantly overexpressed in prostate cancer and metastatic tumors when compared with normal tissues, both at protein and at mRNA levels. Brachyury expression in the cytoplasm correlates with highly aggressive tumors, whereas the presence of Brachyury in the nucleus is correlated with tumor invasion. We found that Brachyury-positive cells present higher viability, proliferation, migration, and invasion rates than Brachyury-negative cells. Microarray analysis further showed that genes co-expressed with Brachyury are clustered in oncogenic-related pathways, namely cell motility, cellcycle regulation, and cell metabolism. Conclusions: Collectively, the present study suggests that Brachyury plays an important role in prostate cancer aggressiveness and points, for the first time, to Brachyury as a significant predictor of poor prostate cancer prognosis. Our work paves the way for future studies assessing Brachyury as a possible prostate cancer therapeutic target.This study was supported by the ICVS internal research funds of participating authors and by the FCT project, ref. PTDC/SAU-MET113415/2009. F. Pinto and N. Pertega-Gomes received fellowships from the FCT, ref. SFRH/BD/81369/2011 and SFRH/BD/61027/2009, respectively. R. P. Andrade was funded by Ciencia2007 Program Contract and Programa Operacional Regional do Norte (ON. 2) - NORTE-07-0124-FEDER-000017

    Technical note: Use of an atmospheric simulation chamber to investigate the effect of different engine conditions on unregulated VOC-IVOC diesel exhaust emissions

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    Diesel exhaust emissions were introduced into an atmospheric simulation chamber and measured using thermal desorption (TD) comprehensive two-dimensional gas chromatography coupled to a flame ionisation detector (GC × GC-FID). An extensive set of measurements were performed to investigate the effect of different engine conditions (i.e. load, speed, driving scenarios) and emission control devices (with or without diesel oxidative catalyst, DOC) on the composition and abundance of unregulated exhaust gas emissions from a light-duty diesel engine, fuelled with ultra-low sulfur diesel (ULSD). A range of exhaust dilution ratios were investigated (range = 1:60 to 1:1158), simulating the chemical and physical transformations of the exhaust gas from near to downwind of an emission source. In total, 16 individual and 8 groups of compounds (aliphatics and single-ring aromatics) were measured in the exhaust gas ranging from volatile to intermediate volatility (VOC-IVOC), providing both detailed chemical speciation and groupings of compounds based on their structure and functionality. Measured VOC-IVOC emission rates displayed excellent reproducibility from replicate experiments using similar exhaust dilution ratios. However, at the extremes of the investigated exhaust dilution ratios (comparison of 1:60 and 1:1158), measured VOC-IVOC emission rates displayed some disagreement owing to poor reproducibility and highlighted the importance of replicate sample measurements. The investigated DOC was found to remove 43±10% (arithmetic mean±experimental uncertainty) of the total speciated VOC-IVOC ( ∑ SpVOC-IVOC) emissions. The compound class-dependant removal efficiencies for the investigated DOC were 39±12% and 83±3% for the aliphatics and single-ring aromatics, respectively. The DOC aliphatic removal efficiency generally decreased with increasing carbon chain length. The  ∑ SpVOC-IVOC emission rates varied significantly with different engine conditions, ranging from 70 to 9268mgkg−1 (milligrams of mass emitted per kilogram of fuel burnt).  ∑ SpVOC-IVOC emission rates generally decreased with increasing engine load and temperature, and to a lesser degree, engine speed. The exhaust gas composition changed considerably as a result of two influencing factors: engine combustion and DOC hydrocarbon (HC) removal efficiency. Increased engine combustion efficiency resulted in a greater percentage contribution of the C7 to C12 n-alkanes to the  ∑ SpVOC-IVOC emission rate. Conversely, increased DOC HC removal efficiency resulted in a greater percentage contribution of the C7 to C12 branched aliphatics to the  ∑ SpVOC-IVOC emission rate. At low engine temperatures ( < 150°C, below the working temperature of the DOC), the contribution of n-alkanes in the exhaust gas increased with increasing combustion efficiency and may be important in urban environments, as n-alkanes are more efficient at producing secondary organic aerosol (SOA) than their branched counterparts. At very high engine temperatures (maximum applied engine speed and load, engine temperature = 700°C), the n-alkane contribution increased by a factor of 1.6 times greater than that observed in the cold-start experiment (most similar to unburnt fuel) and may suggest liquid-fuel-based estimates of SOA yields may be inconsistent with exhaust SOA yields, particularly at high engine speeds and loads (i.e. high engine temperatures). Emission rates were found to be 65 times greater from a cold-start experiment than at maximum applied engine speed and load. To our knowledge, this is the first study which uses an atmospheric simulation chamber to separate the effects of the DOC and combustion efficiency on the exhaust gas composition
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