Shales of the Ediacaran Doushantuo Formation of South China contain a new disc-shaped macrofossil, Eoandromeda octobrachiata, characterized by eight spiral arms that were probably housed within an outer membrane. Alth...Shales of the Ediacaran Doushantuo Formation of South China contain a new disc-shaped macrofossil, Eoandromeda octobrachiata, characterized by eight spiral arms that were probably housed within an outer membrane. Although the presence of eight radiating structures entails a resemblance to cnidarian octocorals as well as to ctenophores, direct homologies with these extant groups are unlikely. Instead we bring attention to the helicospiral morphology of newly reported embryos from the Doushantuo Formation, suggesting that the long-sought adults of the Ediacaran embryonic metazoans have finally been found.展开更多
Two new horizons with macroscopic fossils are reported in the Doushantuo Formation, Ediacaran System, from the Yangtze Gorges area. The fossils were discovered in the lower and middle black shales of the Doushantuo Fo...Two new horizons with macroscopic fossils are reported in the Doushantuo Formation, Ediacaran System, from the Yangtze Gorges area. The fossils were discovered in the lower and middle black shales of the Doushantuo Formation in the new section at Sandouping Town, Zigui County, Hubei Province. The new macroscopic assemblages in- clude Chuaria and Tawuia, and occur below the well- known ”Miaohe Biota”. These fossils indicate that after the Nantuo ice age, macroscopic multicellular organisms gradually increased in abundance and diversity. Simple, discoidal carbonaceous compres- sions such as chuarids are present in the initial macrofossil assemblage of the Doushantuo Stage. This assemblage was eventually replaceded by the more diverse Miaohe macrofossils, including unam- biguously branching forms, in the uppermost Dou- shantuo Formation. The new discovery of carbona- ceous compression macrofossils from the Doushan- tuo Formation in the Yangtze Gorges area provides new evidence for the correlation of late Neoprotero- zoic successions in southern China.展开更多
华南伊迪卡拉系陡山沱组保存的磷酸盐化球状化石中有一部分被认为是最早的后生动物胚胎化石,但由于缺乏成年或幼年过渡期的化石证据,对这些最早微化石的动物属性还一直存在争议。最近在贵州江口县翁会地区伊迪卡拉(震旦)系陡山沱组的页...华南伊迪卡拉系陡山沱组保存的磷酸盐化球状化石中有一部分被认为是最早的后生动物胚胎化石,但由于缺乏成年或幼年过渡期的化石证据,对这些最早微化石的动物属性还一直存在争议。最近在贵州江口县翁会地区伊迪卡拉(震旦)系陡山沱组的页岩中发现一个与"庙河生物群"相似的宏体碳质压膜化石群,其中包含一个盘状的宏体化石新类型——八臂仙母虫(Eoandromeda octobrachiata,Tang et al.2008),具有八条螺旋状辐射的旋臂,封闭在一个包膜内。这种八辐射结构在八射珊瑚和栉水母动物中都可见到,但同时具有的螺旋特性与现生的所有类群都无法对比。在贵州陡山沱组的"瓮安生物群"中发现的球状胚胎化石同样具有螺旋性状,尽管还没有直接的个体发育证据,但我们认为新属种可能代表这些螺旋状胚胎化石的成年实体化石。最新报道的南澳大利亚Rawnsley石英岩层中也发现相似的印痕化石,被归为同一类别,表明华南的"庙河生物群"与澳大利亚的"伊迪卡拉生物群"时代相当。翁会化石库中少量出露的三辐射化石与俄罗斯"白海生物群"的典型分子—Albumares和Anfesta可以对比。新发现的倾斜保存的八臂仙母虫化石和碳质条带呈子午线状排列的核桃状化石,可能是该类化石归属栉水母类的有力证据,这一发现推测可将栉水母类的最早化石记录从"澄江生物群"的早寒武世推前大约3千万年。展开更多
The alternating marine and nonmarine coal-bearing Lower Cretaceous successions are well developed in eastern Heilongjiang, northeastern China, including the Jixi Group in the west and the Longzhaogou Group in the east...The alternating marine and nonmarine coal-bearing Lower Cretaceous successions are well developed in eastern Heilongjiang, northeastern China, including the Jixi Group in the west and the Longzhaogou Group in the east. The correlation of these two lithostratigraphic groups with the nonmarine Jehol Group is important for dating the exceptionally well-preserved Jehol Biota. The Early Cretaceous marine fossils recovered from eastern Heilongjiang include ammonites, bivalves, radiolarians, foraminifers and dinocysts. During the early Aptian transgression the ammonite fauna entered the Hulin and Mishan areas and the bivalve Aucellina fauna in the Jixi area. This enables correlation of the marine lower part of the Chengzihe Formation of the Jixi Group with the Qihulin Formation of the Longzhaogou Group.展开更多
The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As...The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As a result,studies on the RPE have rapidly increased in number over the last few years.Most of these experiments have been performed using unplanted soil as the control,which could potentially lead to incorrect assessment of the RPE.Therefore,we performed a greenhouse experiment to investigate how the choice of control(i.e.,unplanted control and planted control)influenced the quantification of RPE on SOM decomposition and gross nitrogen(N)mineralization,and to link this to differences in microbial and abiotic soil properties between the two controls.In the planted control,planted seedlings were cut at soil surface 5 d before measurement of the RPE.The RPE on SOM decomposition was positive in pine soil and almost 2-fold higher when calculated from the planted control than from the unplanted control.In spruce soil,a negative RPE on SOM decomposition was found when calculated from the planted control,while the RPE was positive when calculated from the unplanted control.No RPE on gross N mineralization was found when calculated from the planted control,while a positive RPE of more than 100%was found when calculated from the unplanted control.The microbial biomass and growth rate were lower,while the inorganic N content was higher in the unplanted control than in the planted control.The microbial community composition and potential enzyme activity in the planted treatment and planted control were similar,but they differed significantly from those in the unplanted control.The results showed that the RPE varied widely depending on the choice of control;thus,we suggest that a planted control,in which the aboveground plant parts are removed only a few days before the measurement of RPE,should be used as the control when elucidating the RPE on belowground C and N cycling responses to environmental change.展开更多
The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Fo...The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin, northern Hebei, China, is revised on the basis of a scanning electron microscope （SEM） examination of the type species M.jingshangensis Wang, 1984, which revealed morphological features not recognized previously. These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced, small tubercles and fine lirae.展开更多
The number of operational satellites and debris objects in the valuable geosynchronous ring has increased steadily over time such that active debris removal missions are necessary to ensure long-term stability. These ...The number of operational satellites and debris objects in the valuable geosynchronous ring has increased steadily over time such that active debris removal missions are necessary to ensure long-term stability. These objects are very large and tumbling, making any mission scenarios requiring physical contact very challenging. In the last 10 years, the concept of using an electrostatic tractor has been investigated extensively. With the electrostatic tractor concept, active charge emission is employed to simultaneously charge the tug or services vehicle, while aiming the charge exhaust onto the passive space debris object to charge it as well. The resulting electrostatic force has been explored to actuate this debris object to a disposal orbit or to detumble the object, all without physical contact. This paper provides a survey of the related research and reviews the charging concepts, the associated electrostatic force and torque modeling, and the feedback control developments, as well as the charge sensing research.展开更多
Objective: Describe children’s toilet habits in a kindergarten setting. Subjects: Forty-one children aged 4-5 years, parents and six teachers participated. Method: Open-ended interviews and observations. Results: In ...Objective: Describe children’s toilet habits in a kindergarten setting. Subjects: Forty-one children aged 4-5 years, parents and six teachers participated. Method: Open-ended interviews and observations. Results: In school children avoided going to toilet, this could cause incontinence. Related Factors: Inadequate toilet standards and differing cleaning routines as at home. Children were uncomfortable and shy using the toilet, and some children seemed to prefer playing and school work instead of going to the toilet during breaks. Conclusion: Children of 4-5 years of age are sometimes not able to control their bladder and bowel habits in an environment differing to home.展开更多
Objective: To evaluate the knowledge of?nutrition?among mothers of children less than two years of age and changes in theoretical knowledge after a nutrition course. Method: A pilot study with a pre-post-test design. ...Objective: To evaluate the knowledge of?nutrition?among mothers of children less than two years of age and changes in theoretical knowledge after a nutrition course. Method: A pilot study with a pre-post-test design. Thirty mothers of children who were less than two years of age from outside Hanoi participated in the study. The mothers’ knowledge of breastfeeding, supplementary food and diet when the child was suffering from diarrhea was collected using 19 self-reported questions. A one-day nutrition course at which the mothers answered the same questions before and after the course was run. Results: All the invited mothers were included in the study. There was a lack of knowledge about breastfeeding and nutrition at baseline, but it improved after the nutrition course. The greatest improvement in knowledge related to breastfeeding less than 30 minutes after delivery, not giving milk or fruit juice instead of breast milk, increasing the frequency of breastfeeding in the event of a smaller amount of milk and knowledge about giving supplementary food after six months. Moreover, the results revealed that the mothers reported better knowledge of the consumption and frequency of more healthy food supplements. Conclusion: There was a lack of knowledge about nutrition among the mothers with children less than two years of age. The course demonstrated effectiveness in every aspect of nutritional knowledge, tested in the posttest. The findings in this study could provide important information for authorities in the health sector to improve the nutritional state of children in the community.展开更多
With the increasing demand for high bandwidth wireless communication systems,and with a congested spectrum in the sub-6 GHz frequency bands,researchers have been looking into exploration of millimeter wave(mmWave)and ...With the increasing demand for high bandwidth wireless communication systems,and with a congested spectrum in the sub-6 GHz frequency bands,researchers have been looking into exploration of millimeter wave(mmWave)and sub-terahertz(subTHz)frequency bands.Channel modeling is essential for system design and performance evaluation of new wireless communication systems.Accurate channel modeling relies on reliable measured channel data,which is collected by high-fidelity channel sounders.Furthermore,it is of importance to understand to which extent channel parameters are frequency dependent in typical deployment scenario(including both indoor short-range and outdoor long-range scenarios).To achieve this purpose,this paper presents a stateof-art long-range 28 GHz and 300 GHz VNA-based channel sounder using optical cable solutions,which can support a measurement range up to 300 m and 600 m in principle,respectively.The design,development and validation of the long-range channel sounders at mmWave and sub-THz bands are reported,with a focus on their system principle,link budget,and backto-back measurements.Furthermore,a measurement campaign in an indoor corridor is performed using the developed 300 GHz system and 28 GHz channel sounding systems.Both measured channels at the 28 GHz and 300 GHz channels are shown to be highly sparse and specular.A higher number of Multi Path Components(MPC)are observed for the 28 GHz system,while the same main MPC are observed for both systems.展开更多
基金Fieldwork and research were funded by the National Natural Science Foundation of China （Grant Nos. 40272015 and 40672022） the China Geology Survey （Grant No. 200213000042 and 1212010511607）.
文摘Shales of the Ediacaran Doushantuo Formation of South China contain a new disc-shaped macrofossil, Eoandromeda octobrachiata, characterized by eight spiral arms that were probably housed within an outer membrane. Although the presence of eight radiating structures entails a resemblance to cnidarian octocorals as well as to ctenophores, direct homologies with these extant groups are unlikely. Instead we bring attention to the helicospiral morphology of newly reported embryos from the Doushantuo Formation, suggesting that the long-sought adults of the Ediacaran embryonic metazoans have finally been found.
基金The authors are particularly grateful to Prof.Xing Yusheng and Wang Xiaofeng for providing the field information and the valuable comments.This work was supported by the National Natural Science Foundation of China(Grant No.40272015)a special grant from China Geological Survey(Grant No.200213000042)to Yin Chongyu.
文摘Two new horizons with macroscopic fossils are reported in the Doushantuo Formation, Ediacaran System, from the Yangtze Gorges area. The fossils were discovered in the lower and middle black shales of the Doushantuo Formation in the new section at Sandouping Town, Zigui County, Hubei Province. The new macroscopic assemblages in- clude Chuaria and Tawuia, and occur below the well- known ”Miaohe Biota”. These fossils indicate that after the Nantuo ice age, macroscopic multicellular organisms gradually increased in abundance and diversity. Simple, discoidal carbonaceous compres- sions such as chuarids are present in the initial macrofossil assemblage of the Doushantuo Stage. This assemblage was eventually replaceded by the more diverse Miaohe macrofossils, including unam- biguously branching forms, in the uppermost Dou- shantuo Formation. The new discovery of carbona- ceous compression macrofossils from the Doushan- tuo Formation in the Yangtze Gorges area provides new evidence for the correlation of late Neoprotero- zoic successions in southern China.
文摘华南伊迪卡拉系陡山沱组保存的磷酸盐化球状化石中有一部分被认为是最早的后生动物胚胎化石,但由于缺乏成年或幼年过渡期的化石证据,对这些最早微化石的动物属性还一直存在争议。最近在贵州江口县翁会地区伊迪卡拉(震旦)系陡山沱组的页岩中发现一个与"庙河生物群"相似的宏体碳质压膜化石群,其中包含一个盘状的宏体化石新类型——八臂仙母虫(Eoandromeda octobrachiata,Tang et al.2008),具有八条螺旋状辐射的旋臂,封闭在一个包膜内。这种八辐射结构在八射珊瑚和栉水母动物中都可见到,但同时具有的螺旋特性与现生的所有类群都无法对比。在贵州陡山沱组的"瓮安生物群"中发现的球状胚胎化石同样具有螺旋性状,尽管还没有直接的个体发育证据,但我们认为新属种可能代表这些螺旋状胚胎化石的成年实体化石。最新报道的南澳大利亚Rawnsley石英岩层中也发现相似的印痕化石,被归为同一类别,表明华南的"庙河生物群"与澳大利亚的"伊迪卡拉生物群"时代相当。翁会化石库中少量出露的三辐射化石与俄罗斯"白海生物群"的典型分子—Albumares和Anfesta可以对比。新发现的倾斜保存的八臂仙母虫化石和碳质条带呈子午线状排列的核桃状化石,可能是该类化石归属栉水母类的有力证据,这一发现推测可将栉水母类的最早化石记录从"澄江生物群"的早寒武世推前大约3千万年。
文摘The alternating marine and nonmarine coal-bearing Lower Cretaceous successions are well developed in eastern Heilongjiang, northeastern China, including the Jixi Group in the west and the Longzhaogou Group in the east. The correlation of these two lithostratigraphic groups with the nonmarine Jehol Group is important for dating the exceptionally well-preserved Jehol Biota. The Early Cretaceous marine fossils recovered from eastern Heilongjiang include ammonites, bivalves, radiolarians, foraminifers and dinocysts. During the early Aptian transgression the ammonite fauna entered the Hulin and Mishan areas and the bivalve Aucellina fauna in the Jixi area. This enables correlation of the marine lower part of the Chengzihe Formation of the Jixi Group with the Qihulin Formation of the Longzhaogou Group.
基金funded by the Swedish Research Council(No.2016-04710,2016)the Knut and Alice Wallenberg Foundation,Sweden(No.2013.0073)+1 种基金China Postdoctoral Science Foundation(No.2021M703135)supported by the Chinese Scholarship Council。
文摘The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOM)decomposition and nutrient turnover,with potential importance for the global CO_(2) budget.As a result,studies on the RPE have rapidly increased in number over the last few years.Most of these experiments have been performed using unplanted soil as the control,which could potentially lead to incorrect assessment of the RPE.Therefore,we performed a greenhouse experiment to investigate how the choice of control(i.e.,unplanted control and planted control)influenced the quantification of RPE on SOM decomposition and gross nitrogen(N)mineralization,and to link this to differences in microbial and abiotic soil properties between the two controls.In the planted control,planted seedlings were cut at soil surface 5 d before measurement of the RPE.The RPE on SOM decomposition was positive in pine soil and almost 2-fold higher when calculated from the planted control than from the unplanted control.In spruce soil,a negative RPE on SOM decomposition was found when calculated from the planted control,while the RPE was positive when calculated from the unplanted control.No RPE on gross N mineralization was found when calculated from the planted control,while a positive RPE of more than 100%was found when calculated from the unplanted control.The microbial biomass and growth rate were lower,while the inorganic N content was higher in the unplanted control than in the planted control.The microbial community composition and potential enzyme activity in the planted treatment and planted control were similar,but they differed significantly from those in the unplanted control.The results showed that the RPE varied widely depending on the choice of control;thus,we suggest that a planted control,in which the aboveground plant parts are removed only a few days before the measurement of RPE,should be used as the control when elucidating the RPE on belowground C and N cycling responses to environmental change.
基金supported by the Project of China Geological Survey (No.1212010610421)the Major Basic Research Projects of the Ministry of Science and Technology,China (National 973 Project No.2006CB701403)+3 种基金the National Natural Science Foundation of China (No.40572005,40632010,J0630967)JSPS Fellowship (ID No.L09522)State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing (No.073106,20082103) (SKLPS)The SEM micrographs were taken through the courtesy of the LEO 1530 VP facility of SKLPS.
文摘The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin, northern Hebei, China, is revised on the basis of a scanning electron microscope （SEM） examination of the type species M.jingshangensis Wang, 1984, which revealed morphological features not recognized previously. These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced, small tubercles and fine lirae.
文摘The number of operational satellites and debris objects in the valuable geosynchronous ring has increased steadily over time such that active debris removal missions are necessary to ensure long-term stability. These objects are very large and tumbling, making any mission scenarios requiring physical contact very challenging. In the last 10 years, the concept of using an electrostatic tractor has been investigated extensively. With the electrostatic tractor concept, active charge emission is employed to simultaneously charge the tug or services vehicle, while aiming the charge exhaust onto the passive space debris object to charge it as well. The resulting electrostatic force has been explored to actuate this debris object to a disposal orbit or to detumble the object, all without physical contact. This paper provides a survey of the related research and reviews the charging concepts, the associated electrostatic force and torque modeling, and the feedback control developments, as well as the charge sensing research.
文摘Objective: Describe children’s toilet habits in a kindergarten setting. Subjects: Forty-one children aged 4-5 years, parents and six teachers participated. Method: Open-ended interviews and observations. Results: In school children avoided going to toilet, this could cause incontinence. Related Factors: Inadequate toilet standards and differing cleaning routines as at home. Children were uncomfortable and shy using the toilet, and some children seemed to prefer playing and school work instead of going to the toilet during breaks. Conclusion: Children of 4-5 years of age are sometimes not able to control their bladder and bowel habits in an environment differing to home.
文摘Objective: To evaluate the knowledge of?nutrition?among mothers of children less than two years of age and changes in theoretical knowledge after a nutrition course. Method: A pilot study with a pre-post-test design. Thirty mothers of children who were less than two years of age from outside Hanoi participated in the study. The mothers’ knowledge of breastfeeding, supplementary food and diet when the child was suffering from diarrhea was collected using 19 self-reported questions. A one-day nutrition course at which the mothers answered the same questions before and after the course was run. Results: All the invited mothers were included in the study. There was a lack of knowledge about breastfeeding and nutrition at baseline, but it improved after the nutrition course. The greatest improvement in knowledge related to breastfeeding less than 30 minutes after delivery, not giving milk or fruit juice instead of breast milk, increasing the frequency of breastfeeding in the event of a smaller amount of milk and knowledge about giving supplementary food after six months. Moreover, the results revealed that the mothers reported better knowledge of the consumption and frequency of more healthy food supplements. Conclusion: There was a lack of knowledge about nutrition among the mothers with children less than two years of age. The course demonstrated effectiveness in every aspect of nutritional knowledge, tested in the posttest. The findings in this study could provide important information for authorities in the health sector to improve the nutritional state of children in the community.
基金supported by EURAMET European Partnership on Metrology Programme (MEWS) and under the framework of European COST INTERACT action(CA20120)
文摘With the increasing demand for high bandwidth wireless communication systems,and with a congested spectrum in the sub-6 GHz frequency bands,researchers have been looking into exploration of millimeter wave(mmWave)and sub-terahertz(subTHz)frequency bands.Channel modeling is essential for system design and performance evaluation of new wireless communication systems.Accurate channel modeling relies on reliable measured channel data,which is collected by high-fidelity channel sounders.Furthermore,it is of importance to understand to which extent channel parameters are frequency dependent in typical deployment scenario(including both indoor short-range and outdoor long-range scenarios).To achieve this purpose,this paper presents a stateof-art long-range 28 GHz and 300 GHz VNA-based channel sounder using optical cable solutions,which can support a measurement range up to 300 m and 600 m in principle,respectively.The design,development and validation of the long-range channel sounders at mmWave and sub-THz bands are reported,with a focus on their system principle,link budget,and backto-back measurements.Furthermore,a measurement campaign in an indoor corridor is performed using the developed 300 GHz system and 28 GHz channel sounding systems.Both measured channels at the 28 GHz and 300 GHz channels are shown to be highly sparse and specular.A higher number of Multi Path Components(MPC)are observed for the 28 GHz system,while the same main MPC are observed for both systems.
