A set S of vertices of a graph G is called a decycling set if G-S is acyclic.The smallest size of a decycling set is called the decycling number of G and is denoted by ∇(G).In this paper,we investigate the decycling n...A set S of vertices of a graph G is called a decycling set if G-S is acyclic.The smallest size of a decycling set is called the decycling number of G and is denoted by ∇(G).In this paper,we investigate the decycling number of type-k Halin graphs,focusing on those that are formed from trees that have just two degrees k and 3.For any type-k Halin graph G of order n,we prove that(k-2)n+k^(2)-4k+5/(k-1)^(2)≤∇(G)≤n+k-3/k-1.The result not only supports the largest forest conjecture due to Albertson and Berman(1976),but also offers a tight lower bound for the decycling number of type-3 Halin graphs and several type-k Halin graphs.Moreover,a new formula to determine the cardinality of any decycling set S of a type-k Halin graph G is provided.展开更多
目的:评价尼妥珠单抗联合吉西他滨(nimotuzumab plus gemcitabine,NG)一线治疗局部晚期或转移性K-Ras野生型胰腺癌患者的经济性,为相关卫生决策提供参考。方法:基于一项多中心、随机、开放标签的Ⅲ期临床试验(NCT02395016)数据构建分区...目的:评价尼妥珠单抗联合吉西他滨(nimotuzumab plus gemcitabine,NG)一线治疗局部晚期或转移性K-Ras野生型胰腺癌患者的经济性,为相关卫生决策提供参考。方法:基于一项多中心、随机、开放标签的Ⅲ期临床试验(NCT02395016)数据构建分区生存模型,模拟时限为5年,循环周期为28 d。比较NG方案和吉西他滨(gemcitabine,G)方案一线治疗局部晚期或转移性K-Ras野生型胰腺癌的经济性。以质量调整生命年(quality-adjusted life year,QALY)作为产出指标并计算增量成本-效果比(incremental cost-effectiveness ratio,ICER),采用单因素敏感性分析及概率敏感性分析评价模型参数变化对结果稳健性的影响。结果:基础分析结果显示,相较于G方案,NG方案人均成本增加304806.15元,人均效用增加0.16 QALYs,ICER为1865405.26元/QALY,高于本研究设定的268074.00元/QALY的意愿支付(willingness-to-pay,WTP)阈值。单因素敏感性分析结果表明,尼妥珠单抗的成本、肿瘤稳定状态效用和肿瘤进展状态效用对ICER的影响较大。概率敏感性分析结果显示,在WTP阈值为268074.00元/QALY时,NG方案具有经济性的概率为0。结论:与G方案相比,NG方案作为一线药物治疗局部晚期或转移性K-Ras野生型胰腺癌不具有经济性。展开更多
A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper.Two discretization schemes are applied to the system with an positive interior fixed point,and two corresponding discrete systems ar...A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper.Two discretization schemes are applied to the system with an positive interior fixed point,and two corresponding discrete systems are obtained.By analyzing the local dynamics of the corresponding discrete system near the interior fixed point,it is showed that this system is not dynamically consistent with the continuous counterpart system.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.11171114,11401576)Hotan Prefecture Science and Technology Bureau General Project(Grant No.20220212)。
文摘A set S of vertices of a graph G is called a decycling set if G-S is acyclic.The smallest size of a decycling set is called the decycling number of G and is denoted by ∇(G).In this paper,we investigate the decycling number of type-k Halin graphs,focusing on those that are formed from trees that have just two degrees k and 3.For any type-k Halin graph G of order n,we prove that(k-2)n+k^(2)-4k+5/(k-1)^(2)≤∇(G)≤n+k-3/k-1.The result not only supports the largest forest conjecture due to Albertson and Berman(1976),but also offers a tight lower bound for the decycling number of type-3 Halin graphs and several type-k Halin graphs.Moreover,a new formula to determine the cardinality of any decycling set S of a type-k Halin graph G is provided.
文摘目的:评价尼妥珠单抗联合吉西他滨(nimotuzumab plus gemcitabine,NG)一线治疗局部晚期或转移性K-Ras野生型胰腺癌患者的经济性,为相关卫生决策提供参考。方法:基于一项多中心、随机、开放标签的Ⅲ期临床试验(NCT02395016)数据构建分区生存模型,模拟时限为5年,循环周期为28 d。比较NG方案和吉西他滨(gemcitabine,G)方案一线治疗局部晚期或转移性K-Ras野生型胰腺癌的经济性。以质量调整生命年(quality-adjusted life year,QALY)作为产出指标并计算增量成本-效果比(incremental cost-effectiveness ratio,ICER),采用单因素敏感性分析及概率敏感性分析评价模型参数变化对结果稳健性的影响。结果:基础分析结果显示,相较于G方案,NG方案人均成本增加304806.15元,人均效用增加0.16 QALYs,ICER为1865405.26元/QALY,高于本研究设定的268074.00元/QALY的意愿支付(willingness-to-pay,WTP)阈值。单因素敏感性分析结果表明,尼妥珠单抗的成本、肿瘤稳定状态效用和肿瘤进展状态效用对ICER的影响较大。概率敏感性分析结果显示,在WTP阈值为268074.00元/QALY时,NG方案具有经济性的概率为0。结论:与G方案相比,NG方案作为一线药物治疗局部晚期或转移性K-Ras野生型胰腺癌不具有经济性。
基金Supported by the Natural Science Foundation of Shandong Province(ZR2009AL010)Project of Shandong Province Higher Educational Science and Technology Program(J09LA51)Program for Innovative Research Team in Ludong University(08-CXB005)
文摘A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper.Two discretization schemes are applied to the system with an positive interior fixed point,and two corresponding discrete systems are obtained.By analyzing the local dynamics of the corresponding discrete system near the interior fixed point,it is showed that this system is not dynamically consistent with the continuous counterpart system.
