Geology, geochronology and isotopic geochemistry of the Xiaoliugou W-Mo ore field in the Qilian Orogen, NW China : case study of a skarn system formed during continental collision

This study is financially supported by the National Natural Science Foundation of China (41502068).The Xiaoliugou W-Mo ore field lies within the mid-Paleozoic North Qilian Orogen, NW China, and hosts a W resource of 48.8 Mt @ 0.4% and 412.6 Mt of Mo @ 0.075%. It contains five deposits, including Xiaoliugou, Qiqing, Guishan, Qibao and Shiji. The main mineralization styles at Xiaoliugou are skarn and veins in which the mineral sequence is scheelite > molybdenite > chalcopyrite and occurs in the endo- and exo-contact zones of granite intrusions. The scheelite-dominated orebodies are overprinted by molybdenite-dominated quartz veins. Two molybdenite samples yielded Silurian Re-Os model ages of 427.4 ± 6.0 Ma and 428.2 ± 6.0 Ma. Three muscovite samples coexisting with molybdenite yielded Middle Devonian Ar-Ar ages of 392.0 ± 2.7 Ma, 391.1 ± 2.7 Ma and 391.4 ± 2.8 Ma. The Re-Os and Ar-Ar ages indicate that the W-Mo mineralization and alteration occurred at ca. 428–391 Ma, which corresponds with regional continental collision within the Qilian Orogen. δ34S for the sulfides molybdenite and pyrite are 7.70–11.67 ‰ and 4.98–13.17 ‰, respectively. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb of the sulfides are 17.98–21.73, 15.34–18.81, and 37.18–38.63, respectively. The granites yield similar corrected (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i, ranging 16.14–19.35, 15.44–15.63, and 37.41–38.31, respectively. Calculated δ18O of the fluid inclusions in quartz range from -3.38–2.34 ‰, whereas the δD of the hydrothermal fluids ranges from -94 to -47 ‰. The S-, Pb-, O- and D-isotopic data imply that the metals originated from the granite intrusion with a minor component sourced from the host sediments, and that the ore-forming fluids were dominated by magmatic-hydrothermal fluids mixed with minor meteoric water.PostprintPeer reviewe

Cost–benefit analysis of a trans-arctic alternative route to the Suez canal: a method based on high-fidelity ship performance, weather, and ice forecast models

Climate change in recent years has produced viable shipping routes in the Arctic. However,\ua0critical uncertainties related to maritime operations in the Arctic make it difficult to predict ship\ua0speeds in ice and, thus, the voyage time and fuel costs. Cost–benefit analysis of alternative Arctic\ua0routes based on accurate environmental condition modeling is required. In this context, this paper\ua0presents a holistic approach that considers the major voyage-related costs of a trans-Arctic route as\ua0an alternative to the conventional routes via the Suez Canal Route (SCR) for existing merchant ships.\ua0This tool is based on high-fidelity models of ship performance, metocean forecasting, and a voyage\ua0optimization algorithm. Case studies are performed based on a general cargo vessel in operation\ua0to quantify realistic expenses inclusive of all the major operational, fuel, and voyage costs of the\ua0specific voyages. A comparison is made between the total costs of the trans-Arctic route and SCR for\ua0different seasons, which proves the economic feasibility of the trans-Arctic route. Overall, this work\ua0can provide valuable insights to help policymakers as well as shipbuilders, owners, and operators\ua0to assess the potential cost-effectiveness and sustainability of future Arctic shipping, thereby better\ua0developing future strategies

A follow-up study on the recovery and reinfection of Omicron COVID-19 patients in Shanghai, China

ABSTRACTLimited follow-up data is available on the recovery of Omicron COVID-19 patients after acute illness. It is also critical to understand persistence of neutralizing antibody (NAb) and of T-cell mediated immunity and the role of hybrid immunity in preventing SARS-CoV-2 reinfection. This prospective cohort study included Omicron COVID-19 individuals from April to June 2022 in Shanghai, China, during a large epidemic caused by the Omicron BA.2 variant. A total of 8945 patients from three medical centres were included in the follow up programme from November 2022 to February 2023. Of 6412 individuals enrolled for the long COVID analysis, 605 (9.4%) individuals experienced at least one sequelae, mainly had fatigue and mental symptoms specific to Omicron BA.2 infection compared with other common respiratory tract infections. During the second-visit, 548 (12.1%) cases of Omicron reinfection were identified. Hybrid immunity with full and booster vaccination had reduced risk of SARS-CoV-2 reinfection by 0.29-fold (95% CI: 0.63–0.81) and 0.23-fold (95% CI: 0.68–0.87), respectively. For 469 participants willing to the hospital during the first visit, those who received full (72 [IQR, 36–156]) or booster (64 [IQR, 28–132]) vaccination had significantly higher neutralizing antibody titers than those with incomplete vaccination (36 [IQR, 16–79]). Moreover, non-reinfection cases had higher neutralizing antibody titers (64 [IQR, 28–152]) compared to reinfection cases (32 [IQR, 20–69])

A follow-up study on the recovery and reinfection of Omicron COVID-19 patients in Shanghai, China

Limited follow-up data is available on the recovery of Omicron COVID-19 patients after acute illness. It is also critical to understand persistence of neutralizing antibody (NAb) and of T-cell mediated immunity and the role of hybrid immunity in preventing SARS-CoV-2 reinfection. This prospective cohort study included Omicron COVID-19 individuals from April to June 2022 in Shanghai, China, during a large epidemic caused by the Omicron BA.2 variant. A total of 8945 patients from three medical centers were included in the follow up program from November, 2022 to February, 2023. Of 6412 individuals enrolled for the long COVID analysis, 605 (9.4%) individuals experienced at least one sequelae, mainly had fatigue and mental symptoms specific to Omicron BA.2 infection compared with other common respiratory tract infections. During the second-visit, 548 (12.1%) cases of Omicron reinfection were identified. Hybrid immunity with full and booster vaccination had reduced risk of SARS-CoV-2 reinfection by 0.29-fold (95% CI: 0.63 - 0.81) and 0.23-fold (95% CI: 0.68 - 0.87), respectively. For 469 participants willing to the hospital during the first visit, those who received full (72 [IQR, 36 - 156]) or booster (64 [IQR, 28 - 132]) vaccination had significantly higher neutralizing antibody titers than those with incomplete vaccination (36 [IQR, 16 - 79]). Moreover, non-reinfection cases had higher neutralizing antibody titers (64 [IQR, 28 - 152]) compared to reinfection cases (32 [IQR, 20 - 69]).</p