265 research outputs found
Modelling the costs of non-conventional oil: A case study of Canadian bitumen
Keywords JEL Classification High crude oil prices, uncertainties about the consequences of climate change and the eventual decline of conventional oil production raise the issue of alternative fuels, such as non-conventional oil and biofuels. This paper describes a simple probabilistic model of the costs of nonconventional oil, including the role of learning-by-doing in driving down costs. This forward-looking analysis quantifies the effects of both learning and production constraints on the costs of supplying bitumen which can then be upgraded into synthetic crude oil, a substitute to conventional oil. The results show large uncertainties in the future costs of supplying bitumen from Canadian oil sands deposits, with a 90% confidence interval of 12 in 2025, and 15 in 2050 (2005 US$). The influence of each parameter on the supply costs is examined, with the minimum supply cost, the learning rate, and the depletion curve exponent having the largest influence. Over time, the influence of the learning rate on the supply costs decreases, while the influence of the depletion curve exponent increases. Climate change; Non-conventional oil; Exhaustible resources; Technological change; Uncertainty
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The Effect of CO2 Pricing on Conventional and Non-Conventional Oil Supply and Demand
What would be the effect of CO2 pricing on global oil supply and demand? This paper introduces a model describing the interaction between conventional and non-conventional oil supply in a Hotelling framework and under CO2 constraints. The model assumes that nonconventional crude oil enters the market when conventional oil supply alone is unable to meet demand, and the social cost of CO2 is included in the calculation of the oil rent at that time. The results reveal the effect of a CO2 tax set at the social cost of CO2 on oil price and demand and the uncertainty associated with the time when conventional oil production might become unable to meet demand. The results show that a tax on CO2 emissions associated with fuel use would reduce oil demand despite the effect of lower future rents, and would delay the time when conventional oil supply is unable to satisfy demand. More precisely, between 81 and 99% of the CO2 tax is carried into the oil price despite the counter-balancing effect of the reduced rent. A CO2 tax on fuel use set at the social cost of CO2 would delay by 25 years the time when conventional oil production is unable to meet oil demand, from 2019 to 2044 (mean value). The results show that this date is very sensitive to the price elasticity of demand and the demand growth rate, which shows the great potential of demand-side measures to smooth the transition towards low-carbon liquid fuel alternatives
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Supplying Synthetic Crude Oil from Canadian Oil Sands: A Comparative Study of the Costs and CO2 Emissions of Mining and In-Situ Recovery
High crude oil prices and the eventual decline of conventional oil production raise the issue of alternative fuels such as non-conventional oil. The paper describes a simple probabilistic model of the costs of synthetic crude oil (SCO) produced from Canadian oil sands. Synthetic crude oil is obtained by upgrading bitumen that is first produced through mining or in-situ recovery techniques. This forward-looking analysis quantifies the effects of learning and production constraints on the costs of supplying synthetic crude oil from Canadian bitumen deposits. The results show the uncertainties associated with the future costs of synthetic crude oil. Carbon costs have a large impact of the total costs of synthetic crude oil, in particular in the case of synthetic crude oil from in-situ bitumen, due to the carbon-intensity of the recovery techniques. The influence of each parameter on the supply costs is examined. In the case of mined SCO, the maximum production rate, the ultimate recovery rate and the depletion parameters show the largest influence on the results, while learning parameters dominate in the case of in-situ SCO
Renal papillary carcinoma: CT and MRI features
AbstractPurposeTo describe the CT and MRI appearances of papillary renal cell carcinoma.Materials and methodsRetrospective study of 102 papillary carcinomas in 79 patients, 81 tumors examined by CT and 56 by MRI. Tumor size, homogeneity and contrast enhancement were recorded.ResultsThe most common presentation of papillary renal cell carcinoma was a small homogeneous hypovascular tumor both on CT and MRI. Eighty-nine percent of lesions were hypointense on T2 weighted images compared to the renal parenchyma. Seventeen percent of the lesions did not significantly enhance with contrast on CT. All of the lesions examined on MRI had a significant enhancement percentage. Calcifications were rare and only seen in 7% of cases (CT). The second most common presentation was a bulky necrotic tumor. In addition, atypical types of disease were found which were difficult to diagnose, including infiltrating tumors and tumors with a fatty component.ConclusionA homogeneous hypovascular renal tumor which is hypointense on T2 weighted images should suggest a diagnosis of papillary carcinoma. Some papillary carcinomas do not enhance significantly on CT. MRI is then required to diagnose the renal tumor
Qui meurt aprĂšs une nĂ©phrectomie pour cancer ? Ătude des facteurs de risque de dĂ©cĂšs, des causes de dĂ©cĂšs et des rĂ©unions de morbi-mortalitĂ© (Ă©tude UroCCR-33)
BACKGROUND AND METHODS: Nephrectomy is the treatment for renal cell cancer from T1-4 tumors but remains at risk. To determine the thirty-day mortality rate after nephrectomy for cancer and to identify causes and risk factors of death in order to find clinical applications. From 2014 to 2017, we performed a retrospective multicentric analysis of prospectively collected data study involving the French network for research on kidney cancer (UroCCR). All patients who died after nephrectomy for cancer during the first thirty days were identified. Patients\u27 characteristics, causes of death and morbidity and mortality reviews reports were analyzed for each death.
RESULTS AND LIMITATIONS: In total, 2578 patients underwent nephrectomy and 35 deaths occurred. The thirty-day mortality rate was 1.4%. In univariate analysis, symptoms at diagnosis (P=0.006, OR=2.56 IC (1.3-5.03)), c stage superior to cT1 (P<0.0001, OR=6.13 IC (2.8-13.2)), cT stage superior to cT2 (P<0.0001, OR=8.8 IC (4.39-17.8)), nodal invasion (P<0.0001, OR=4.6 IC (1.9-10.7)), distant metastasis (P=0.001, OR=4.01 IC (1.7-8.9)), open surgery (P<0.0001, OR=0.272 IC (0.13-0.54)) and radical nephrectomy (P=0.007, OR=2.737 IC (1.3-5.7)) were risk factors of thirty-day mortality. In a multivariable model, only cT stage superior to T2 (P=0.015, OR=3.55 IC (1.27-10.01)) was a risk factor of thirty-day mortality. The main cause of postoperative death was pulmonary (n=15; 43%). The second cause was postoperative digestive sepsis for 7 patients (20%). Only 2 morbidity and mortality reviews had been done for the 35 deaths. Limitations are related to the thirty-day mortality criteria and descriptive study design.
CONCLUSIONS: Symptomatic patients, stage cTNM and type and techniques of surgery are determinants of thirty-day mortality after nephrectomy for cancer. The first cause of postoperative death is pulmonary. Morbidity and mortality reviews should be considered to better understand causes of death and to reduce early mortality after nephrectomy for cancer.
LEVEL OF EVIDENCE: 4
Ăvaluation prĂ©clinique et clinique dâun outil dĂ©veloppĂ© pour la planification opĂ©ratoire des chirurgies lithiasiques : « Kidney Stone Calculator »
Kidney Stone Calculator (KSC) est un outil que nous avons dĂ©veloppĂ© pour mesurer le volume lithiasique total (VLT) et estimer la durĂ©e opĂ©ratoire de lithotritie laser endocorporelle (LLE) au cours de lâurĂ©tĂ©rorĂ©noscopie souple (URS-S), Ă partir du scanner abdominopelvien prĂ©opĂ©ratoire non injectĂ© (TDM AP IV-). Lâobjectif de cette Ă©tude Ă©tait de rĂ©aliser une Ă©valuation prĂ©clinique et cli-nique de cet outil
Mutations in BHD and TP53 genes, but not in HNF1ÎČ gene, in a large series of sporadic chromophobe renal cell carcinoma
BHD, TP53, and HNF1ÎČ on chromosome 17 were studied in 92 cases of renal cell carcinoma (46 chromophobe, 19 clear cell, 18 oncocytoma, and nine papillary). Six, thirteen, and zero cases had, respectively BHD, TP53, and HNF1ÎČ mutations, (84% mutations involved chromophobe), suggesting a role for BHD and TP53 in chromophobe subtype
Cytoreductive Nephrectomy in the Tyrosine Kinase Inhibitor Era: A Question That May Never Be Answered.
Despite great interest, two randomised controlled trials (RCTs) of cytoreductive nephrectomy in the tyrosine kinase inhibitor setting in metastatic renal cell carcinoma have either closed early (SURTIME) or are recruiting very slowly (CARMENA) after 7 yr. Challenges in RCT delivery in uro-oncologic surgery are many. Multiple steps are needed to ensure strong recruitment to trials addressing important urologic cancer questions. Feasibility/pilot studies are key stepping stones towards successful delivery of surgical RCTs
Progress towards lightning control using lasers
Lightning research needs on-demand lightning strikes, because of the random character of natural lightning. Lasers have been proposed as alternatives to the current technique using rocket-pulled wires, because they would expectedly provide more flexibility. However, high-energy, nanosecond lasers cannot provide long connected plasma channels. In contrast, we recently reported the triggering of electric events in thunderclouds using ultrashort laser pulses. Further improvements of the laser pulse sequence and experiment geometry are discussed
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