This study explores the tradeoff relationship between the number of initial attack firefighting resources and the level of fire ignition prevention efforts mitigating the probability of human-made fires in the Republi...This study explores the tradeoff relationship between the number of initial attack firefighting resources and the level of fire ignition prevention efforts mitigating the probability of human-made fires in the Republic of Korea,where most fires are caused by human activities.To examine this tradeoff relationship,we develop a hybrid model that combines a robust optimization model with a stochastic simulation model.The robust optimization minimizes the expected number of fires not receiving a pre-defined response,such as the number of firefighting resources that must arrive at the fire within half an hour,subject to budget constraints and uncertainty about the daily number and location of fires.The simulation model produces a set of fire scenarios in which a combination of number,location,ignition time,and intensity of fires occur.Results show that fire ignition prevention is as cost-effective as initial attack firefighting resources given the current budget in the Republic of Korea for reducing the expected number of fires not covered by the predefined response.The mixed policy of fire suppression and fire prevention may produce some gains in efficiency relative to the dominant policy of strong fire suppression strategies.展开更多
This paper aims at analyzing and evaluating investments in rangeland management through the use of the discount rate tool. The most important parameter which is considered when estimating the discount rate is the life...This paper aims at analyzing and evaluating investments in rangeland management through the use of the discount rate tool. The most important parameter which is considered when estimating the discount rate is the lifetime of the investment, which varies depending on the kind of the intervention. An undeniable characteristic of rangelands is their rich biodiversity. However, the fact that not all the flora and fauna has been recorded yet, suggests the need for using the lowest possible discount rate （but not zero）, giving thus a high value on the benefits that will arise for future generations always in the light of sustainable development. At the same time, a sensitivity analysis has to be performed in order to determine the upper and lower limit of return on investment, so that the decision-maker in charge can be more flexible on the evaluation Of an investment proposal.展开更多
Objective： To study the effect of internal fixation performed at different times on therapeutic outcomes of Schatzker IV-VI tibial plateau fractureS. Methods： The clinical data of 42 cases ofSehatzker IV- VI tibial...Objective： To study the effect of internal fixation performed at different times on therapeutic outcomes of Schatzker IV-VI tibial plateau fractureS. Methods： The clinical data of 42 cases ofSehatzker IV- VI tibial plateau fractures treated in our department were analyzed retrospectively. Among these 42 patients, 21 re- ceived surgical treatment within 12 h after injury, （Group I）, the other 2 [ were first treated by traction or piaster fixation followed by a delayed internal fixation after soft tissue swell- i ing subsided （Group II）. The surgical time, comPlications, length of hospital stay, cost of hospitalization, and time for i fracture union, as well as functional recovery were analyzed and compared between the two groups. Results： After 10-28 months follow-up （mean 16.5 months）, except 5 cases who lost to follow-upl no differ-ences were found between the two groups regarding surgi- cal time, preoperative and postoperative complications, heal- ing time or the Hospital for Special Surgery （HSS） score at the end of follow-up, but significant differences were found in the length of hospital stay, cost of hospitalization and HSS score at 3 months after operation （P〈0.05）. Conclusion： Under certain conditions, early internal fixation for Schatzker IV-VI tibial plateau fracture is feasible, which can shorten the length of hospital stay, decrease the cost of hospitalization and promote early functional rehabilitation.展开更多
Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formida...Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formidable challenge is to balance the contradiction between wide band gaps and large second harmonic generation(SHG) effects in IR NLO materials. In the present work, we proposed new kinds of NLO active units, d^0 transition metal fluorooxofunctional groups for designing mid-IR NLO materials. By studying a series of d^0 transition metal oxyfluorides(TMOFs),the influences of fluorooxo-functional groups with different d^0 configuration cations on the band gap and SHG responses were explored. The results reveal that the fluorooxo-functional groups with different d^0 configuration cations can enlarge band gaps in mid-IR NLO materials. The first-principles calculations demonstrate that the nine alkali/alkaline earth metals d^0 TMOFs exhibit wide band gaps(all the band gaps >3.0 e V), large birefringence Δn(> 0.07), and two W/Mo TMOFs also exhibit large SHG responses. Moreover, by comparing with other fluorooxo-functional groups, it is found that introducing fluorine into building units is an effective way to enhance optical performance. These d^0 TMOFs with superior fluorooxo-functional groups represent a new exploration family of the mid-IR region, which sheds light on the design of mid-IR NLO materials possessing large band gap.展开更多
基金supported by 2014 Yeungnam University Research Grant
文摘This study explores the tradeoff relationship between the number of initial attack firefighting resources and the level of fire ignition prevention efforts mitigating the probability of human-made fires in the Republic of Korea,where most fires are caused by human activities.To examine this tradeoff relationship,we develop a hybrid model that combines a robust optimization model with a stochastic simulation model.The robust optimization minimizes the expected number of fires not receiving a pre-defined response,such as the number of firefighting resources that must arrive at the fire within half an hour,subject to budget constraints and uncertainty about the daily number and location of fires.The simulation model produces a set of fire scenarios in which a combination of number,location,ignition time,and intensity of fires occur.Results show that fire ignition prevention is as cost-effective as initial attack firefighting resources given the current budget in the Republic of Korea for reducing the expected number of fires not covered by the predefined response.The mixed policy of fire suppression and fire prevention may produce some gains in efficiency relative to the dominant policy of strong fire suppression strategies.
文摘This paper aims at analyzing and evaluating investments in rangeland management through the use of the discount rate tool. The most important parameter which is considered when estimating the discount rate is the lifetime of the investment, which varies depending on the kind of the intervention. An undeniable characteristic of rangelands is their rich biodiversity. However, the fact that not all the flora and fauna has been recorded yet, suggests the need for using the lowest possible discount rate （but not zero）, giving thus a high value on the benefits that will arise for future generations always in the light of sustainable development. At the same time, a sensitivity analysis has to be performed in order to determine the upper and lower limit of return on investment, so that the decision-maker in charge can be more flexible on the evaluation Of an investment proposal.
文摘Objective： To study the effect of internal fixation performed at different times on therapeutic outcomes of Schatzker IV-VI tibial plateau fractureS. Methods： The clinical data of 42 cases ofSehatzker IV- VI tibial plateau fractures treated in our department were analyzed retrospectively. Among these 42 patients, 21 re- ceived surgical treatment within 12 h after injury, （Group I）, the other 2 [ were first treated by traction or piaster fixation followed by a delayed internal fixation after soft tissue swell- i ing subsided （Group II）. The surgical time, comPlications, length of hospital stay, cost of hospitalization, and time for i fracture union, as well as functional recovery were analyzed and compared between the two groups. Results： After 10-28 months follow-up （mean 16.5 months）, except 5 cases who lost to follow-upl no differ-ences were found between the two groups regarding surgi- cal time, preoperative and postoperative complications, heal- ing time or the Hospital for Special Surgery （HSS） score at the end of follow-up, but significant differences were found in the length of hospital stay, cost of hospitalization and HSS score at 3 months after operation （P〈0.05）. Conclusion： Under certain conditions, early internal fixation for Schatzker IV-VI tibial plateau fracture is feasible, which can shorten the length of hospital stay, decrease the cost of hospitalization and promote early functional rehabilitation.
基金supported by Tianshan Innovation Team Program (2018D14001)the National Natural Science Foundation of China (51922014 and 11774414)+2 种基金Shanghai Cooperation Organization Science and Technology Partnership Program (2017E01013)Xinjiang Program of Introducing High-Level Talents, Fujian Institute of Innovation, Chinese Academy of Sciences (FJCXY18010202)the Western Light Foundation of CAS (2017-XBQNXZ-B-006 and 2016QNXZ-B-9)
文摘Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formidable challenge is to balance the contradiction between wide band gaps and large second harmonic generation(SHG) effects in IR NLO materials. In the present work, we proposed new kinds of NLO active units, d^0 transition metal fluorooxofunctional groups for designing mid-IR NLO materials. By studying a series of d^0 transition metal oxyfluorides(TMOFs),the influences of fluorooxo-functional groups with different d^0 configuration cations on the band gap and SHG responses were explored. The results reveal that the fluorooxo-functional groups with different d^0 configuration cations can enlarge band gaps in mid-IR NLO materials. The first-principles calculations demonstrate that the nine alkali/alkaline earth metals d^0 TMOFs exhibit wide band gaps(all the band gaps >3.0 e V), large birefringence Δn(> 0.07), and two W/Mo TMOFs also exhibit large SHG responses. Moreover, by comparing with other fluorooxo-functional groups, it is found that introducing fluorine into building units is an effective way to enhance optical performance. These d^0 TMOFs with superior fluorooxo-functional groups represent a new exploration family of the mid-IR region, which sheds light on the design of mid-IR NLO materials possessing large band gap.
