We consider a variant of M/M/1 where customers arrive singly or in pairs. Each single and one member of each pair is called primary;the other member of each pair is called secondary. Each primary joins the queue upon ...We consider a variant of M/M/1 where customers arrive singly or in pairs. Each single and one member of each pair is called primary;the other member of each pair is called secondary. Each primary joins the queue upon arrival. Each secondary is delayed in a separate area, and joins the queue when “pushed” by the next arriving primary. Thus each secondary joins the queue followed immediately by the next primary. This arrival/delay mechanism appears to be new in queueing theory. Our goal is to obtain the steady-state probability density function (pdf) of the workload, and related quantities of interest. We utilize a typical sample path of the workload process as a physical guide, and simple level crossing theorems, to derive model equations for the steady-state pdf. A potential application is to the processing of electronic signals with error free components and components that require later confirmation before joining the queue. The confirmation is the arrival of the next signal.展开更多
目的探究血清叉头盒蛋白M1(forkhead box protein M1,FOXM1)和胰岛素样生长因子2(insulin-like growth factor 2,IGF2)表达对老年心力衰竭合并肺炎患者预后的预测价值。方法将邯郸市中心医院2021年3月~2022年6月收治的126例老年心力衰...目的探究血清叉头盒蛋白M1(forkhead box protein M1,FOXM1)和胰岛素样生长因子2(insulin-like growth factor 2,IGF2)表达对老年心力衰竭合并肺炎患者预后的预测价值。方法将邯郸市中心医院2021年3月~2022年6月收治的126例老年心力衰竭并发肺炎患者设为病例组,并根据随访情况将122例患者分为预后不良组(n=33)和预后良好组(n=89),另选取该院同期126例健康体检者为对照组。检测两组(病例组和对照组)血清FOXM1和IGF2水平,检测病例组用力肺活量(forced vital capacity,FVC)和第一秒用力呼容积(forced expiratory volume in one second,FEV1)。采用Spearman分析法分析老年心力衰竭并发肺炎患者血清FOXM1和IGF2水平与心功能分级的相关性;受试者工作特征(receiver operating characteristic,ROC)曲线分析血清FOXM1和IGF2水平对老年心力衰竭并发肺炎患者预后的预测价值。结果与对照组比较,病例组血清FOXM1(2.39±0.55 vs 1.06±0.21)和IGF2(71.33±7.96pg/ml vs 47.82±5.14pg/ml)水平明显较高,差异有统计学意义(t=25.358,27.581,均P<0.05);与预后良好组比较,预后不良组血清FOXM1(3.87±1.06 vs 1.95±0.51)和IGF2水平(85.88±9.54pg/ml vs 69.14±8.73pg/ml)明显较高,差异具有统计学意义(t=13.453,9.174,均P<0.05);预后良好组和预后不良组心功能分级比较差异有统计学意义(χ^(2)=7.120,P<0.05),且与预后不良组比较,预后良好组FEV1(1.24±0.32L vs 1.08±0.25L)和FEV1/FVC(55.46%±5.77%vs 52.30%±5.38%)明显较高,差异有统计学意义(t=2.592,2.735,均P<0.05);老年心力衰竭并发肺炎患者血清FOXM1水平和IGF2水平与心功能分级呈显著正相关(r=0.496,0.517,均P<0.05)。ROC曲线结果显示,血清FOXM1单独预测老年心力衰竭并发肺炎患者预后的曲线下面积(area under the curve,AUC)为0.854(95CI%:0.779~0.912),其敏感度、特异度分别为75.76%,86.52%,最佳截断值为2.75;IGF2单独预测老年心力衰竭并发肺炎患者预后的AUC为0.874(95CI%:0.802~0.927),其敏感度、特异度分别为72.73%,85.39%,最佳截断值为78.30 pg/ml;二者联合预测老年心力衰竭并发肺炎患者预后的AUC显著大于血清FOXM1和IGF2单独诊断的AUC(Z=2.413,2.737,P=0.006,0.016)。结论血清FOXM1和IGF2水平在老年心力衰竭并发肺炎患者中升高,且二者联合检测对患者预后具有较高的预测价值。展开更多
文摘We consider a variant of M/M/1 where customers arrive singly or in pairs. Each single and one member of each pair is called primary;the other member of each pair is called secondary. Each primary joins the queue upon arrival. Each secondary is delayed in a separate area, and joins the queue when “pushed” by the next arriving primary. Thus each secondary joins the queue followed immediately by the next primary. This arrival/delay mechanism appears to be new in queueing theory. Our goal is to obtain the steady-state probability density function (pdf) of the workload, and related quantities of interest. We utilize a typical sample path of the workload process as a physical guide, and simple level crossing theorems, to derive model equations for the steady-state pdf. A potential application is to the processing of electronic signals with error free components and components that require later confirmation before joining the queue. The confirmation is the arrival of the next signal.
文摘目的探究血清叉头盒蛋白M1(forkhead box protein M1,FOXM1)和胰岛素样生长因子2(insulin-like growth factor 2,IGF2)表达对老年心力衰竭合并肺炎患者预后的预测价值。方法将邯郸市中心医院2021年3月~2022年6月收治的126例老年心力衰竭并发肺炎患者设为病例组,并根据随访情况将122例患者分为预后不良组(n=33)和预后良好组(n=89),另选取该院同期126例健康体检者为对照组。检测两组(病例组和对照组)血清FOXM1和IGF2水平,检测病例组用力肺活量(forced vital capacity,FVC)和第一秒用力呼容积(forced expiratory volume in one second,FEV1)。采用Spearman分析法分析老年心力衰竭并发肺炎患者血清FOXM1和IGF2水平与心功能分级的相关性;受试者工作特征(receiver operating characteristic,ROC)曲线分析血清FOXM1和IGF2水平对老年心力衰竭并发肺炎患者预后的预测价值。结果与对照组比较,病例组血清FOXM1(2.39±0.55 vs 1.06±0.21)和IGF2(71.33±7.96pg/ml vs 47.82±5.14pg/ml)水平明显较高,差异有统计学意义(t=25.358,27.581,均P<0.05);与预后良好组比较,预后不良组血清FOXM1(3.87±1.06 vs 1.95±0.51)和IGF2水平(85.88±9.54pg/ml vs 69.14±8.73pg/ml)明显较高,差异具有统计学意义(t=13.453,9.174,均P<0.05);预后良好组和预后不良组心功能分级比较差异有统计学意义(χ^(2)=7.120,P<0.05),且与预后不良组比较,预后良好组FEV1(1.24±0.32L vs 1.08±0.25L)和FEV1/FVC(55.46%±5.77%vs 52.30%±5.38%)明显较高,差异有统计学意义(t=2.592,2.735,均P<0.05);老年心力衰竭并发肺炎患者血清FOXM1水平和IGF2水平与心功能分级呈显著正相关(r=0.496,0.517,均P<0.05)。ROC曲线结果显示,血清FOXM1单独预测老年心力衰竭并发肺炎患者预后的曲线下面积(area under the curve,AUC)为0.854(95CI%:0.779~0.912),其敏感度、特异度分别为75.76%,86.52%,最佳截断值为2.75;IGF2单独预测老年心力衰竭并发肺炎患者预后的AUC为0.874(95CI%:0.802~0.927),其敏感度、特异度分别为72.73%,85.39%,最佳截断值为78.30 pg/ml;二者联合预测老年心力衰竭并发肺炎患者预后的AUC显著大于血清FOXM1和IGF2单独诊断的AUC(Z=2.413,2.737,P=0.006,0.016)。结论血清FOXM1和IGF2水平在老年心力衰竭并发肺炎患者中升高,且二者联合检测对患者预后具有较高的预测价值。
