140,290 research outputs found
Manganese(I)-Catalyzed Substitutive C-H Allylation
No full textThe first manganese(I)-catalyzed C-H allylations with ample scope were achieved by carboxylate assistance. The highly selective C-H/C-O functionalizations proved viable with densely substituted allyl carbonates, and the organometallic C-H allylation strategy set the stage for expedient latestage diversification with excellent levels of positional selectivity
Difference based Ridge and Liu type Estimators in Semiparametric Regression Models
Full text linkWe consider a difference based ridge regression estimator and a Liu type estimator of the regression parameters in the partial linear semiparametric regression model, y = Xβ + f + ε. Both estimators are analysed and compared in the sense of mean-squared error. We consider the case of independent errors with equal variance and give conditions under which the proposed estimators are superior to the unbiased difference based estimation technique. We extend the results to account for heteroscedasticity and autocovariance in the error terms. Finally, we illustrate the performance of these estimators with an application to the determinants of electricity consumption in Germany.Difference based estimator; Differencing estimator, Differencing matrix, Liu estimator, Liu type estimator, Multicollinearity, Ridge regression estimator, Semiparametric model
Model system to evaluate impacts of vehicle purchase tax and fuel tax on household greenhouse gas emissions
No full textThis paper proposes a model system to forecast household-level greenhouse gas emissions (GHGEs) from private transportation and evaluate the effects of car-related taxation schemes on vehicle emissions. The system contains four submodels that specifically capture households' vehicle and vintage, quantity, usage, and GHGE rates (GHGERs) by vehicle type. The vehicle GHGERs are calculated with the Motor Vehicle Emission Simulator 2014, which is authorized by the Environmental Protection Agency. The whole model system was applied to the Washington, D.C., metropolitan area. The 2009 National Household Travel Survey was employed with supplementary data from Consumer Reports, American Fact Finder, and 2009 state motor vehicle registrations. The study proposed two tax schemes, vehicle purchase tax and fuel tax, and predicted their effects on reductions in vehicle GHGEs. The average annual GHGE per vehicle was 5.86 tons of carbon dioxide-equivalent gas without the proposed taxes. After two taxation policies were implemented, the results showed the following: (a) the impacts on reducing GHGEs from fuel taxes were higher than those from purchase taxes, (b) purchase taxes reduced GHGEs mainly by decreasing the number of cars of households with more vehicles, and (c) fuel taxes successfully reduced GHGEs by decreasing the use of cars by households with fewer vehicles. The model system can be extended to other zones, counties, states, and nations
Corrigendum: Liu W-B, Wang C-Y, Tang Y-N, Wang Y, Pei W-X, Yan C-C (2024) Six new species of Cryptochironomus Kieffer (Diptera, Chironomidae) from the Nearctic region. ZooKeys 1200: 275–302. doi: 10.3897/zookeys.1200.119225
Full text linkCorrigendum: Liu W-B, Wang C-Y, Tang Y-N, Wang Y, Pei W-X, Yan C-C (2024) Six new species of Cryptochironomus Kieffer (Diptera, Chironomidae) from the Nearctic region. ZooKeys 1200: 275–302. https://doi.org/10.3897/ zookeys.1200.11922
Irpex subulatus Z. B. Liu & Y. C. Dai, comb. nov.
No full textIrpex subulatus (Ryvarden) Z.B. Liu & Y.C. Dai, comb. nov. (Fig. 4) MycoBank no.— MB 841368 Basionym: Oxyporus subulatus Ryvarden, Nordic Journal of Botany 2(3): 280 (1982). ≡ Flavodon subulatus (Ryvarden) F. Wu, Jia J. Chen & Y.C. Dai, Mycologia 109(5): 761 (2017). = Flavodon ambrosius D.R. Simmons, You Li, C.C. Bateman & J. Hulcr, Mycotaxon 131(2): 279 (2016). Holotype:— Thailand. Cangwat Lamphum, Doi Inthanond, 20 February 1979, Ryvarden 17843 Description: See Hjortstam & Ryvarden (1982, as Oxyporus subulatus). Specimens examined: CHINA. Henan Province, Xiuwu County, Yuntaishan, on fallen angiosperm trunk, 4 September 2009, B. K. Cui, Cui 7275 (BJFC 005762); Hubei Province, Shennongjia, Muyu, on fallen trunk of Celtis, 25 September 2004, Y. C. Dai, Dai 5929 (BJFC 010379, IFP 003711); Shanxi Province, Zhouzhi County, Taibaishan Nature Reserve, on fallen angiosperm trunk, 25 October 2006, H. S. Yuan, Yuan 2733 (BJFC 001406, IFP 003703); THAILAND. Chiang Mai, on fallen angiosperm trunk, 24 July 2016, Y. C. Dai, Dai 16719 (BJFC 022826). Notes: Simmons et al. (2016) described Flavodon ambrosius as a new species. In fact, we found that its description fits Oxyporus subulatus well, and its holotype (Hulcr 6853) sequences of ITS and LSU (ITS: KR 119072; LSU: KR 119075) are almost the same as those from Oxyporus subulatus. Wu et al. (2017) transferred Oxyporus subulatus to Flavodon based on the results of the phylogenetic analyses. Herein, we place this species in Irpex based on morphological and phylogenetic evidence (Fig. 1).Published as part of Tian, Xue-Mei, Man, Xiao-Wu & Liu, Zhan-Bo, 2022, Irpex jinshaensis sp. nov. and I. subulatus comb. nov. (Irpicaceae, Polyporales), evidenced by morphological characters and phylogenetic analysis, pp. 73-82 in Phytotaxa 533 (1) on pages 79-80, DOI: 10.11646/phytotaxa.533.1.4, http://zenodo.org/record/597413
Evaluating policies to reduce greenhouse gas emissions from private transportation
No full textThis paper proposes a model system to forecast household greenhouse gas emissions (GHGEs) from private transportation. The proposed model combines an integrated discrete-continuous car ownership model with MOVES 2014. Four modeling components are calibrated and applied to the calculation of GHGEs: vehicle quantity, vehicle type and vintage, miles traveled, and rates of GHGEs. The model is applied to the Washington D.C. Metropolitan Area. Three tax schemes are evaluated: vehicle ownership tax, purchase tax and fuel tax. We calculate that the average GHGEs per vehicle is 5.15 tons of carbon dioxide-equivalent (CO2E) gases. Our results show that: (a) a fuel tax is the most effective way to reduce vehicle GHGEs, especially for households with fewer vehicles; (b) a purchase tax reduces vehicle GHGEs mainly by decreasing vehicle quantity for households with more vehicles; and (c) an ownership tax reduces vehicle GHGEs by decreasing both vehicle quantity and miles traveled
An analytical demonstration of coupling schemes between magnetohydrodynamic codes and eddy current codes
No full textIn order to model a magnetohydrodynamic (MHD) instability that strongly couples to external conducting structures (walls and/or coils) in a fusion device, it is often necessary to combine a MHD code solving for the plasma response, with an eddy current code computing the fields and currents of conductors. We present a rigorous proof of the coupling schemes between these two types of codes. One of the coupling schemes has been introduced and implemented in the CARMA code {[}R. Albanese, Y. Q. Liu, A. Portone, G. Rubinacci, and F. Villone, IEEE Trans. Magn. 44, 1654 (2008); A. Portone, F. Villone, Y. Q. Liu, R. Albanese, and G. Rubinacci, Plasma Phys. Controlled Fusion 50, 085004 (2008)] that couples the MHD code MARS-F {[}Y. Q. Liu, A. Bondeson, C. M. Fransson, B. Lennartson, and C. Breitholtz, Phys. Plasmas 7, 3681 (2000)] and the eddy current code CARIDDI {[}R. Albanese and G. Rubinacci, Adv. Imaging Electron Phys. 102, 1 (1998)]. While the coupling schemes are described for a general toroidal geometry, we give the analytical proof for a cylindrical plasma
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