BACKGROUND Varicella(chickenpox)and herpes zoster(shingles)are outcomes of varicella-zoster virus(VZV)infection,and understanding their incidence trends is vital for public health planning.AIM To conduct an ambispecti...BACKGROUND Varicella(chickenpox)and herpes zoster(shingles)are outcomes of varicella-zoster virus(VZV)infection,and understanding their incidence trends is vital for public health planning.AIM To conduct an ambispective epidemiological study by analyzing the main epidemiological characteristics of VZV infection during an 18 year-period(2000-2018).METHODS We used descriptive and epidemiological methods to characterize chickenpox in Bulgaria,the city of Plovdiv and the region for a period of 18 years(2000-2018).RESULTS The average incidence of varicella-zoster infection for the period 2000–2018 in the Plovdiv region was estimated at 449.58‰.The highest relative share of the infection was assessed in the month of January at 13.6%,and the lowest in the months of August and September at 2.9%(both months).The age group most affected by the infection was 1-4 years,followed by 5-9 years.This corresponds to the so-called"pro-epidemic population"-a phenomenon typical for airborne infections,confirming their mass impact on the perpetuation of VZV infection.CONCLUSION Our findings reveal significant insights into VZV epidemiology,including age-specific incidence rates,clinical manifestations,and vaccination impact.This comprehensive analysis contributes to the broader understanding of VZV infec-tion dynamics and may inform evidence-based preventive measures.展开更多
从预印本的科研工作者主体的视角揭示了主导预印本发展的力量。以Web of Science(WoS)数学领域5个子学科期刊2015年发表的15313篇arXiv论文和43669篇非arXiv(non-arXiv)论文作为研究对象,综合运用文献计量学、补充计量学和数理统计等科...从预印本的科研工作者主体的视角揭示了主导预印本发展的力量。以Web of Science(WoS)数学领域5个子学科期刊2015年发表的15313篇arXiv论文和43669篇非arXiv(non-arXiv)论文作为研究对象,综合运用文献计量学、补充计量学和数理统计等科学计量学理论方法,从活跃国家和机构、作者学术年龄、预印本影响力及作者选择编好4个维度对arXiv和non-arXiv论文进行了对比分析。结果表明,与其他预印本发表活跃国家相比,我国学者对预印本的接受程度显著偏低;发表预印本的科研工作者以年轻人为主导,我国预印本作者学术年龄年轻化程度最为明显;预印本影响力具有国别特征,我国预印本影响力特征最为特殊,即相比读者优势,我国预印本的引用优势更为突出,且WoS使用量显著偏高;作者对预先进行自存档的论文的选择具有选择偏好。我国学界应提高利用预印本进行科学交流的意识,积极应对并引领科学交流方式的变革,建设国际国内预印本双循环科学交流模式,既要加入国际学术交流,又要注重科研成果的内循环。展开更多
In view of the mechanics characteristic of cemented tailings backfill(CTB)at early age,the separation Hopkinson pressure bar test device was used to explore the effects of curing age and impact energy.A total of 48 CT...In view of the mechanics characteristic of cemented tailings backfill(CTB)at early age,the separation Hopkinson pressure bar test device was used to explore the effects of curing age and impact energy.A total of 48 CTB samples with diameter of 50 mm and length of 25 mm were prepared with curing ages of 3,5,7 and 9 d.Impact tests under different impact energy(10,20,30 and 40 J)were carried out.The microstructure of CTB at different ages was analyzed by scanning electron microscopy(SEM).The results show that,the curing age mainly affects the mechanical properties and internal structure of early-age CTB.With increasing curing age,the mechanical properties of early-age CTB change from viscoelasticity to brittleness.The impact energy mainly affects the response of dynamic peak compressive strength to strain rate.Under low strain rate,the structure of CTB is broken,but still has bearing capacity,affecting the formation of later strength.It is concluded that the structural loses completely under the action of high strain rate.Therefore,the control of impact energy and the protection of curing age should be fully considered in actual production process.展开更多
A comparison between a numerical model (NM) and an investigating model (IM) on the uplift of the Qinghai_Xizang Plateau was conducted. Results show that the NM is capable of describing the uplifting processes of the p...A comparison between a numerical model (NM) and an investigating model (IM) on the uplift of the Qinghai_Xizang Plateau was conducted. Results show that the NM is capable of describing the uplifting processes of the plateau. They are in good agreement with each other concerning the major uplifting processes.展开更多
At about 3000 C14-year BP or 1200 cal. yrs BC, the Baltic Sea experienced a mega-tsunami with a wave-height of 10 m or more, and a run-up height of up to 16.5 m. This event had significant geological and archaeologica...At about 3000 C14-year BP or 1200 cal. yrs BC, the Baltic Sea experienced a mega-tsunami with a wave-height of 10 m or more, and a run-up height of up to 16.5 m. This event had significant geological and archaeological effects. We explore the records from the Lake M?laren area in Sweden. The tsunami event is linked to seismic ground shaking and methane venting tectonics at several sites. The triggering factor is proposed to be the Kaali meteor impact in Estonia of the same age. The documentation of a mega-tsunami in the middle of the Bronze Age has wide implications both in geology and in archaeology. The archaeological key sites at Annelund and Apalle are reinterpreted in terms of tsunami wave actions remodelling stratigraphy. By extensive coring, we are able to trace the tsunami effects in both off-shore and on-shore environment. At the time of the event, sea level was at +15 m (due to isostatic uplift). The tsunami wave erosion is traced 13.5 m below sea level. The tsunami run-up over land is traced to +29.5 m to +31.5 m (occasionally even higher), implying a run-up of 14.5 - 16.5 m. In ?ngermanland, the tsunami event was absolutely dated at 1171 varve years BC. Archaeologically, the tsunami event coincides well with the transition between Periods II and III of the South Scandinavian Bronze Age. Period III has traditionally been difficult to identify in the cultural materials of the Lake M<span style="font-family:Verdana;">?</span><span style="font-family:Verdana;">laren region.</span>展开更多
基金the European Union-NextGenerationEU,through the National Recovery and Resilience Plan of the Republic of Bulgaria,No.BG-RRP-2.004-0008.
文摘BACKGROUND Varicella(chickenpox)and herpes zoster(shingles)are outcomes of varicella-zoster virus(VZV)infection,and understanding their incidence trends is vital for public health planning.AIM To conduct an ambispective epidemiological study by analyzing the main epidemiological characteristics of VZV infection during an 18 year-period(2000-2018).METHODS We used descriptive and epidemiological methods to characterize chickenpox in Bulgaria,the city of Plovdiv and the region for a period of 18 years(2000-2018).RESULTS The average incidence of varicella-zoster infection for the period 2000–2018 in the Plovdiv region was estimated at 449.58‰.The highest relative share of the infection was assessed in the month of January at 13.6%,and the lowest in the months of August and September at 2.9%(both months).The age group most affected by the infection was 1-4 years,followed by 5-9 years.This corresponds to the so-called"pro-epidemic population"-a phenomenon typical for airborne infections,confirming their mass impact on the perpetuation of VZV infection.CONCLUSION Our findings reveal significant insights into VZV epidemiology,including age-specific incidence rates,clinical manifestations,and vaccination impact.This comprehensive analysis contributes to the broader understanding of VZV infec-tion dynamics and may inform evidence-based preventive measures.
文摘从预印本的科研工作者主体的视角揭示了主导预印本发展的力量。以Web of Science(WoS)数学领域5个子学科期刊2015年发表的15313篇arXiv论文和43669篇非arXiv(non-arXiv)论文作为研究对象,综合运用文献计量学、补充计量学和数理统计等科学计量学理论方法,从活跃国家和机构、作者学术年龄、预印本影响力及作者选择编好4个维度对arXiv和non-arXiv论文进行了对比分析。结果表明,与其他预印本发表活跃国家相比,我国学者对预印本的接受程度显著偏低;发表预印本的科研工作者以年轻人为主导,我国预印本作者学术年龄年轻化程度最为明显;预印本影响力具有国别特征,我国预印本影响力特征最为特殊,即相比读者优势,我国预印本的引用优势更为突出,且WoS使用量显著偏高;作者对预先进行自存档的论文的选择具有选择偏好。我国学界应提高利用预印本进行科学交流的意识,积极应对并引领科学交流方式的变革,建设国际国内预印本双循环科学交流模式,既要加入国际学术交流,又要注重科研成果的内循环。
基金Project(CXZZBS2019126)supported by the Innovative Support Program for Doctoral Students in Hebei Province,ChinaProject(QN2019078)supported by the Science and Technology Research Project of Colleges and University in Hebei Province,ChinaProject(51774137)supported by the National Natural Science Foundation of China。
文摘In view of the mechanics characteristic of cemented tailings backfill(CTB)at early age,the separation Hopkinson pressure bar test device was used to explore the effects of curing age and impact energy.A total of 48 CTB samples with diameter of 50 mm and length of 25 mm were prepared with curing ages of 3,5,7 and 9 d.Impact tests under different impact energy(10,20,30 and 40 J)were carried out.The microstructure of CTB at different ages was analyzed by scanning electron microscopy(SEM).The results show that,the curing age mainly affects the mechanical properties and internal structure of early-age CTB.With increasing curing age,the mechanical properties of early-age CTB change from viscoelasticity to brittleness.The impact energy mainly affects the response of dynamic peak compressive strength to strain rate.Under low strain rate,the structure of CTB is broken,but still has bearing capacity,affecting the formation of later strength.It is concluded that the structural loses completely under the action of high strain rate.Therefore,the control of impact energy and the protection of curing age should be fully considered in actual production process.
文摘A comparison between a numerical model (NM) and an investigating model (IM) on the uplift of the Qinghai_Xizang Plateau was conducted. Results show that the NM is capable of describing the uplifting processes of the plateau. They are in good agreement with each other concerning the major uplifting processes.
文摘At about 3000 C14-year BP or 1200 cal. yrs BC, the Baltic Sea experienced a mega-tsunami with a wave-height of 10 m or more, and a run-up height of up to 16.5 m. This event had significant geological and archaeological effects. We explore the records from the Lake M?laren area in Sweden. The tsunami event is linked to seismic ground shaking and methane venting tectonics at several sites. The triggering factor is proposed to be the Kaali meteor impact in Estonia of the same age. The documentation of a mega-tsunami in the middle of the Bronze Age has wide implications both in geology and in archaeology. The archaeological key sites at Annelund and Apalle are reinterpreted in terms of tsunami wave actions remodelling stratigraphy. By extensive coring, we are able to trace the tsunami effects in both off-shore and on-shore environment. At the time of the event, sea level was at +15 m (due to isostatic uplift). The tsunami wave erosion is traced 13.5 m below sea level. The tsunami run-up over land is traced to +29.5 m to +31.5 m (occasionally even higher), implying a run-up of 14.5 - 16.5 m. In ?ngermanland, the tsunami event was absolutely dated at 1171 varve years BC. Archaeologically, the tsunami event coincides well with the transition between Periods II and III of the South Scandinavian Bronze Age. Period III has traditionally been difficult to identify in the cultural materials of the Lake M<span style="font-family:Verdana;">?</span><span style="font-family:Verdana;">laren region.</span>
