Ionospheric scintillation refers to rapid radio signal amplitude and phase fluctuations due to small-scale irregularities in the ionosphere.Occurring primarily at equatorial and low latitudes,scintillation is linked t...Ionospheric scintillation refers to rapid radio signal amplitude and phase fluctuations due to small-scale irregularities in the ionosphere.Occurring primarily at equatorial and low latitudes,scintillation is linked to equatorial plasma bubbles(EPBs),regions of depleted plasma density that form after sunset.Ionospheric scintillation typically occurs from post-sunset hours until midnight.Post-sunset EPBs can be enhanced or suppressed during geomagnetic storms,depending on local sunset timing and how it relates to the storm's main or recovery phases.This study analyzes ionospheric scintillation in Indonesia,located at low geomagnetic and geographic latitudes,during geomagnetic events from 2003 to 2024.Using the S4 index,scintillation was examined with data from seven observation stations during geomagnetic storm events.Geomagnetic activity was evaluated using Dst,SYM-H,and AE indices,employing Superposed Epoch Analysis(SEA)to assess scintillation occurrence linked to minimum SYM-H,defined as epoch 0 to represent the storm peak or the onset of recovery phase in each event.The analysis categorized geomagnetic storms into weak-moderate(–100 nT<min.Dst≤–30 nT)and strong(min.Dst≤–100 nT),and examined their dependence on the local time of minimum SYM-H.Results indicate that scintillation first appears~6 hours after epoch 0 in weak-moderate geomagnetic storms,and~12 hours after epoch 0 in strong geomagnetic storms.The average AE index returns to its baseline value(quiet condition)~6 and~12 hours after epoch 0 for weak-moderate and strong geomagnetic storms,respectively.Further analysis based on the classification of the local time of epoch 0 shows that scintillation occurrence is not observed in post-sunset hours when epoch 0 falls between 16:00 and 19:00 LT for weak-moderate geomagnetic storms.In strong geomagnetic storms,scintillation occurrence during post-sunset hours is absent when epoch 0 is between 10:00 and 19:00 LT.Notably,when the minimum SYM-H(epoch 0)nearly coincides with local sunset,scintillation activity occurs around sunset in both weak-moderate and strong geomagnetic storms.Furthermore,when epoch 0 falls within midnight until early morning,scintillation can be generated in the post-sunset hours before epoch 0.Still,post-midnight scintillation is not observed in the equatorial region during the recovery phase of either weak-moderate and strong storm events.Our findings show that when sunset falls before or coincide with epoch 0,the likelihood of post-sunset EPB and scintillation increases,due to the prompt-penetration electric field(PPEF)in the main phase of storm.The disturbance dynamo electric field(DDEF)in the recovery phase driven by equatorward winds from auroral Joule heating operates for at least 6-and 12-hours post-epoch 0 in the cases of weak-moderate and strong geomagnetic storms,respectively.When the local sunset falls within these operational DDEF periods,post-sunset EPBs will likely be suppressed,inhibiting ionospheric scintillation during post-sunset hours.Finally,this study provides essential information for developing more accurate ionospheric scintillation prediction models in space weather services in equatorial regions.展开更多
目的:明确用基因表达水平的贝叶斯分析(Bayesian analysis of gene expression levels,B A G E L)所建立的胃癌弱差异基因表达谱(fold change<1.5)的特异性及生物学意义.方法:Cluster3.0聚类分析基因DNA甲基转移酶3A[DNA(cytosine-5-...目的:明确用基因表达水平的贝叶斯分析(Bayesian analysis of gene expression levels,B A G E L)所建立的胃癌弱差异基因表达谱(fold change<1.5)的特异性及生物学意义.方法:Cluster3.0聚类分析基因DNA甲基转移酶3A[DNA(cytosine-5-)-methyltransferase3 a l p h a,D N M T3A]、发育分化增强因子2(development and differentiation-enhancing f a c t o r 2,D D E F2)、分化群59(c l u s t e r o f differentiation 59,CD59)的表达;机器学习和模式识别技术对弱差异基因表达谱(fold change<1.5,P<0.001)进行特征提取;GoMiner软件分析弱差异表达基因D N M T3A、DDEF2、CD59的生物学功能;RT-PCR在实验室验证弱差异表达基因DNMT3A、DDEF2、CD59在胃癌及癌旁配对组织中mRNA的表达水平.结果:从弱差异基因表达谱中得到能够识别样本类别的62个分类特征基因和4个分类能力较强的基因;GoMiner分析表明这组基因参与细胞黏附、细胞吞噬、免疫调节、基因甲基化、转录调控等重要生物学作用;RT-PCR确定基因表达变化与芯片中基因表达谱的数据一致,证实了弱差异基因表达谱的可靠性和灵敏性.结论:通过BAGEL分析得到的fold change<1.5的弱差异基因表达谱灵敏可靠,在肿瘤发生发展中关系密切.展开更多
基金supported by the National Research and Innovation Agency(BRIN),Indonesia.
文摘Ionospheric scintillation refers to rapid radio signal amplitude and phase fluctuations due to small-scale irregularities in the ionosphere.Occurring primarily at equatorial and low latitudes,scintillation is linked to equatorial plasma bubbles(EPBs),regions of depleted plasma density that form after sunset.Ionospheric scintillation typically occurs from post-sunset hours until midnight.Post-sunset EPBs can be enhanced or suppressed during geomagnetic storms,depending on local sunset timing and how it relates to the storm's main or recovery phases.This study analyzes ionospheric scintillation in Indonesia,located at low geomagnetic and geographic latitudes,during geomagnetic events from 2003 to 2024.Using the S4 index,scintillation was examined with data from seven observation stations during geomagnetic storm events.Geomagnetic activity was evaluated using Dst,SYM-H,and AE indices,employing Superposed Epoch Analysis(SEA)to assess scintillation occurrence linked to minimum SYM-H,defined as epoch 0 to represent the storm peak or the onset of recovery phase in each event.The analysis categorized geomagnetic storms into weak-moderate(–100 nT<min.Dst≤–30 nT)and strong(min.Dst≤–100 nT),and examined their dependence on the local time of minimum SYM-H.Results indicate that scintillation first appears~6 hours after epoch 0 in weak-moderate geomagnetic storms,and~12 hours after epoch 0 in strong geomagnetic storms.The average AE index returns to its baseline value(quiet condition)~6 and~12 hours after epoch 0 for weak-moderate and strong geomagnetic storms,respectively.Further analysis based on the classification of the local time of epoch 0 shows that scintillation occurrence is not observed in post-sunset hours when epoch 0 falls between 16:00 and 19:00 LT for weak-moderate geomagnetic storms.In strong geomagnetic storms,scintillation occurrence during post-sunset hours is absent when epoch 0 is between 10:00 and 19:00 LT.Notably,when the minimum SYM-H(epoch 0)nearly coincides with local sunset,scintillation activity occurs around sunset in both weak-moderate and strong geomagnetic storms.Furthermore,when epoch 0 falls within midnight until early morning,scintillation can be generated in the post-sunset hours before epoch 0.Still,post-midnight scintillation is not observed in the equatorial region during the recovery phase of either weak-moderate and strong storm events.Our findings show that when sunset falls before or coincide with epoch 0,the likelihood of post-sunset EPB and scintillation increases,due to the prompt-penetration electric field(PPEF)in the main phase of storm.The disturbance dynamo electric field(DDEF)in the recovery phase driven by equatorward winds from auroral Joule heating operates for at least 6-and 12-hours post-epoch 0 in the cases of weak-moderate and strong geomagnetic storms,respectively.When the local sunset falls within these operational DDEF periods,post-sunset EPBs will likely be suppressed,inhibiting ionospheric scintillation during post-sunset hours.Finally,this study provides essential information for developing more accurate ionospheric scintillation prediction models in space weather services in equatorial regions.
文摘目的:明确用基因表达水平的贝叶斯分析(Bayesian analysis of gene expression levels,B A G E L)所建立的胃癌弱差异基因表达谱(fold change<1.5)的特异性及生物学意义.方法:Cluster3.0聚类分析基因DNA甲基转移酶3A[DNA(cytosine-5-)-methyltransferase3 a l p h a,D N M T3A]、发育分化增强因子2(development and differentiation-enhancing f a c t o r 2,D D E F2)、分化群59(c l u s t e r o f differentiation 59,CD59)的表达;机器学习和模式识别技术对弱差异基因表达谱(fold change<1.5,P<0.001)进行特征提取;GoMiner软件分析弱差异表达基因D N M T3A、DDEF2、CD59的生物学功能;RT-PCR在实验室验证弱差异表达基因DNMT3A、DDEF2、CD59在胃癌及癌旁配对组织中mRNA的表达水平.结果:从弱差异基因表达谱中得到能够识别样本类别的62个分类特征基因和4个分类能力较强的基因;GoMiner分析表明这组基因参与细胞黏附、细胞吞噬、免疫调节、基因甲基化、转录调控等重要生物学作用;RT-PCR确定基因表达变化与芯片中基因表达谱的数据一致,证实了弱差异基因表达谱的可靠性和灵敏性.结论:通过BAGEL分析得到的fold change<1.5的弱差异基因表达谱灵敏可靠,在肿瘤发生发展中关系密切.
