Serial Interval Distribution of COVID-19 among Iranian Reported Confirmed Cases

Type of manuscript: short report Introduction:  Serial interval refers to the average time between of the onset of the symptoms of two successive cases. Serial interval distribution can be used for the calculation of the basic reproduction number (R0), transmission rate, and study of an epidemic trend. This study aims to investigate the mean, standard deviation, and distribution of serial interval among the confirmed cases of COVID-19 using a Gamma distribution.      Methods: To determine the serial interval, 60 confirmed infected cases of COVID-19 (based on PCR test results) in February 20th-May 20th, 2020 were selected as the cases. For these cases, 37 transmissions occurred. The data of the dates of the occurrence of primary and secondary symptoms were collected by referring to the COVID-19 surveillance system and interviewing the patients Results: The findings showed that the median and mean of the serial interval were 3.0 and 4.5± 3.5 days. The findings showed that the median of the serial interval was 3.0 days (with the inter-quartile range of 2.0-6.0). The mean serial interval was 4.5± 3.5 days (95% confidence interval: 3.1-5.5). Conclusions: Our report showed a shorter period for a serial interval less than the previous reported interval in China. It seems that regarding the shorter serial interval reported in this study, the basic reproduction numbers reported by the first papers published in Iran have been overestimated regarding the serial interval of 7.5 days. Key words: COVID-19, Serial interval, Gamma distributio

Serial Interval Distribution of COVID-19 among Iranian Reported Confirmed Cases

Type of manuscript: short report Introduction:  Serial interval refers to the average time between of the onset of the symptoms of two successive cases. Serial interval distribution can be used for the calculation of the basic reproduction number (R0), transmission rate, and study of an epidemic trend. This study aims to investigate the mean, standard deviation, and distribution of serial interval among the confirmed cases of COVID-19 using a Gamma distribution.      Methods: To determine the serial interval, 60 confirmed infected cases of COVID-19 (based on PCR test results) in February 20th-May 20th, 2020 were selected as the cases. For these cases, 37 transmissions occurred. The data of the dates of the occurrence of primary and secondary symptoms were collected by referring to the COVID-19 surveillance system and interviewing the patients Results: The findings showed that the median and mean of the serial interval were 3.0 and 4.5± 3.5 days. The findings showed that the median of the serial interval was 3.0 days (with the inter-quartile range of 2.0-6.0). The mean serial interval was 4.5± 3.5 days (95% confidence interval: 3.1-5.5). Conclusions: Our report showed a shorter period for a serial interval less than the previous reported interval in China. It seems that regarding the shorter serial interval reported in this study, the basic reproduction numbers reported by the first papers published in Iran have been overestimated regarding the serial interval of 7.5 days. Key words: COVID-19, Serial interval, Gamma distributio

油茶鲜果预处理方式对低温压榨油茶籽油品质的影响

为更 多地保留活性成分，提高油茶籽油品质，研究了油茶鲜果6种不同预处理方式(剥壳-摊晒、直接摊晒、堆沤-摊晒、剥壳-烘干、直接烘干、堆沤-烘干)对油茶籽主要成分以及低温压榨油茶籽油中3种理化指标(酸值、过氧化值、多环芳烃)和4种微量活性成分(维生素E、维生素K1、角鲨烯、多酚)的影响。结果表明：油茶鲜果预处理方式对油茶籽主要成分(脂肪、蛋白质、淀粉）影响不大;6种不同预处理方式对低温压榨油茶籽油的理化指标和微量活性成分均有一定的影响，其中剥壳-烘干处理油茶鲜果在油茶籽油的酸值、多环芳烃、维生素E、角鲨烯指标上较其他预处理方式存在一定优势。综上，采用剥壳-烘干对油茶鲜果进行预处理，可在一定程度上提高油茶籽油品质。 In order to retain more active components and improve the quality of oil-tea camellia seed oil, the effects of six different pretreatment methods of fresh Camellia oleifera fruit(shelling-spreading, direct spreading, retting-spreading, shelling-drying, direct drying, and retting-drying) on the main components of oil-tea camellia seed, as well as three physicochemical indexes (acid value, peroxide value, and polycyclic aromatic hydrocarbons) and four trace active components (vitamin E, vitamin K1, squalene, and polyphenols) of low-temperature pressed oil-tea camellia seed oil were studied. The results showed that the different pretreatment methods had little effects on the main components (fat, protein, starch) of oil-tea camellia seed, and had certain effects on the physicochemical indexes and trace active components of low-temperature pressed oil-tea camellia seed oil. The shelling-drying method had certain advantages over other pretreatment methods in acid value, polycyclic aromatic hydrocarbons, vitamin E, and squalene of oil-tea camellia seed oil. In conclusion, the shelling-drying pretreatment of fresh Camellia oleifera fruit can improve the quality of oil-tea camellia seed oil to a certain extent

环境水样中~(129)I分析及其在环境示踪中的应用

~(129)I是碘的唯一长寿命放射性同位素(半衰期为1570万年),目前环境中~(129)I主要来源于人类核活动,尤其是欧洲核燃料后处理厂的排放。人工~(129)I的大量释放使环境中~(129)I的水平大幅度升高,具有明显的空间分布规律,并且随排放时间呈现明显的变化趋势。~(129)I是一种理想的环境示踪剂,可应用于核环境安全监测,包括核事故监测和评价、核燃料后处理厂~(129)I排放和环境影响评价以及应用于环境过程示踪研究。陆地环境水样中稳定碘(~(127)I)水平较低,~(129)I含量更是处于超低水平,因此,准确分析其中超低含量~(129)I及其化学形态是研究难点。本文系统地评述了环境水样中~(129)I及其形态的分析方法,~(129)I的水平、分布及其在核设施环境安全监测和稳定碘的地球化学循环示踪领域应用的研究进展。</p

Geomorphic, hydroclimatic and hydrothermal controls on the formation of lithium brine deposits in the Qaidam Basin, northern Tibetan Plateau, China

Qaidam Basin is a hyperarid inland basin with an area of 121 x 10(3) km(2) located on the northern Tibetan Plateau. Today, one fourth of the basin is covered by playas and hypersaline lakes. Nearly 80% of brine lithium found in China is contained in four salt lakes: Bieletan (BLT), DongTaijinaier (DT), XiTaijinaier (XT) and Yiliping (YLP). In the past decade, great attention was paid to improving the technology for the extraction of lithium from the brine deposits, but studies on origin and mode of formation of the brine deposits remained limited. Our recent investigations found that: (1) similar to 748.8 t of lithium was transported annually into the lower catchment of the four salt lakes via the Hongshui-Nalinggele River (H-N River), the largest river draining into the Qaidam Basin, (2) Li+-rich brines are formed only in salt lakes associated with inflowing rivers with Li+ concentrations greater than 0.4 mg/L, and (3) the water Li+ concentration is positively correlated with both the inflowing river and the associated subsurface brine, including saline lakes with low lithium concentrations. These findings clearly indicate that long-term input of Li+ from the H-N River controls the formation of lithium brine deposits. Here we determine that the source of the lithium is from hydrothermal fields where two active faults converge in the upper reach of the Hongshui River. The hydrothermal fields are associated with a magmatic heat source, as suggested by the high Li+ and As3+ content water from geysers. Based on the assumption of a constant rate of lithium influx, we estimate that the total reserves of lithium were likely formed since the postglacial period. Our data indicate that lithium reserves in each of the four salt lakes depend on the influx of Li+-bearing water from the H-N River. The data also suggest that during the progradation of the alluvial Fan I, the H-N River drained mostly into the BLT salt lake until the Taijinaier River shifted watercourse to the north and began to feed the salt lakes of the DT, XT and YLP, alongside with the Fan II progradation. The inference is consistent with stratigraphic evidence from the sediment cores of the four salt lakes. One of the major findings of our work is the importance of the contrasting hydroclimatic conditions between the high mountains containing ice caps and the terminal salt lakes. The greater than 4000 m of relief in the watershed enables a massive amount of ions, such as K+, to be weathered and transported together with detrital material from the huge, relatively wet alpine regions to the hyperarid terminal basins, where intense evaporation rapidly enriches the lake water, resulting in evaporite deposition and associated K+- and Li+-rich brine deposits.</p

利用放射性碳（14C）示踪华山冬季化石源CO2 随海拔高度变化特征

放射性碳（14C）是化石源 CO2 最有效的示踪剂，为了更好地了解华山冬季化石源 CO2 的时空变化特征，于 2014 年冬季在华山三个不同海拔高度&mdash;&mdash;玉泉院（504 m）、北峰（1634 m）、 东峰（2079 m）进行大气 CO2 采样。通过放射性碳同位素分析研究发现：华山冬季不同海拔高度 大气 CO2 浓度随海拔升高而减小，三个海拔高度大气 CO2 平均浓度依次为 461.8&plusmn;14.1 ppm（ppm 表示 &mu;L&middot;L&ndash;1）、 414.6&plusmn;2.7 ppm 和 413.2&plusmn;3.4 ppm，皆高于我国四个大气 CO2 本底站点的同期浓 度水平。不同海拔高度大气 CO2 浓度及其 &delta;13C 值呈显著的反相关关系， R2 = 0.906，表明华山 大气 CO2 主要受区域生态系统的时空变化和源汇特征影响，而海洋的影响较弱。三个不同海拔 高度的化石源 CO2 浓度均值依次为 42.3 &plusmn; 5.7 ppm、 14.9 &plusmn; 3.8 ppm 和 10.6 &plusmn; 1.0 ppm，表明华山 不同海拔高度大气 CO2 都受到化石源 CO2 不同程度的影响。华山冬季化石源 CO2 浓度和海拔高 度具有显著的反相关关系， R2=0.914，随着海拔的不断升高，化石源 CO2 浓度逐渐减小。利用 Hysplit模式分层后向轨迹分析结果表明：在采样时段内，玉泉院和北峰受到同源路径气团的影响， 其化石源 CO2 浓度呈现出较一致的变化趋势，东峰受到异源路径气团的影响，其化石源 CO2 浓 度呈现出不同的变化趋势。因此，在分析评价高海拔地区化石源 CO2 浓度时，不仅要考虑到近 源排放影响，同样不能忽视远源传输影响。</p

KARAKTERISTIK TEPUNG TALAS VARIETAS BENTUL DAN SATOIMO HASIL FERMENTASI TERKENDALI DENGAN INOKULUM KOMERSIAL

Taro is one of non-rice carbohydrate sources which is rich in dietary fiber and minerals, mainly potassium, magnesium, calcium, dan phosphorus. The objectives of this research were to obtain taro flour with high amylose content and various pasting properties for different food ingredients through controlled fermentation technology using commercial inoculums. There are two taro varieties studied, namely Bentul and Satoimo. The fermentation time conducted were 12, 24, 36, and 48 hours. The commercial inoculums added were NKL, Bimo CF, and Fermipan. The results showed that fermentation of taro with Bimo CF for 48 hours increase the amylose content (66.82% for Bentul variety and 61.08% for Satoimo). The growth of mold contributed to the increase in amylose content. Longer fermentation time increase the breakdown and final viscosity of Bentul taro flour, but decrease the same characteristics in Satoimo flour. Fermented bentul taro flour has amylograph pattern similar to type A, while Satoimo has type C. Fermentation using Bimo CF for 48 hours produced the highest final viscosity in Bentul taro flour (3405 cP) thus it is potential to be used as a filler in products processed at low temperature. Meanwhile Satoimo taro produced flour with lowest breakdown viscosity (0.75 cP), therefore it is potential to be used as a filler in products processed at high temperature

Measurements of vertical and horizontal distributions of ozone over Beijing from 2007 to 2010

The vertical distributions of ozone (O-3) over a mega city (Beijing, China), and the horizontal O-3 distributions in the lower troposphere (2-3.6 km) over Beijing and its surrounding areas located in the North China Plain (NCP), were analyzed based on the aircraft measurements from 159 flights during 2007-2010. The results are highlighted as follows: (1) There was a peak of O-3 concentration occurring at 1 km over Beijing, and the peak values ranged between 60 and 120 ppbv. (2) There was an O-3 minimum at the surface. The minimum was largely caused by the chemical reaction of NO + O-3. This process produced about 30 ppbv of the O-3 reduction below 0.5 km in the morning (9:00-10:00). (3) There was a transition altitude (similar to 1 km), below which the ozone formation was in a VOC-limited condition, and above which the ozone formation was in a NOx-limited condition. (4) The analysis of the horizontal distribution shows that O-3 concentrations were enhanced in the downwind of the city plumes. This result suggests that there was an important regional O-3 chemical production in the NCP region.</p

~(129)I加速器质谱分析研究

通过对~(129)I加速器质谱(AMS)分析中影响敏度和准确度各种参数的研究,如靶电极制备、压样、靶样中辅助介质(Matrix)的选择及使用比例等,优化了用于3 MV加速器质谱仪的SO-110型离子源的条件参数,确定~(129)I-AMS测量的最佳靶电极材料为Cu,最佳的辅助介质为Nb粉末,Nb与AgI样品的最佳体积比为3∶1。在此条件下可以获得稳定且持续的I-束流进行测量~(129)I/~(127)I原子比值,实验测得西安加速器质谱仪的~(129)I/~(127)I本底值为1.52&times;10~(-14)。</p

Evaporite minerals of the lower 538.5 m sediments in a long core from the Western Qaidam Basin, Tibet

Qaidam Basin is a tectonically controlled Mesozoic-Cenozoic depression on the northern margin of the Tibetan Plateau. A 938.5 m-long core was drilled in the Qahansilatu sub-basin in the western Qaidam Basin, with an average core recovery of 95%. It revealed alternating salt layers and carbonate clay layers. Samples were collected at 10-40 cm intervals for mineralogical analysis by XRD and chemical analysis by ICP-OES. The lower 538.5 m sediments are composed of halite, gypsum, anhydrite, gaylussite, calcite, aragonite, ankerite, dolomite, and an unnamed mineral (Mg(0.92)Ca(0.0)8CO(3)center dot 3H(2)O), with trace eugsterite. The mother brines could be Na-type, Na-Ca-type, Na-Ca-(Mg)-type, Ca-(Na)-type, Ca-(Mg)-(Na)-type, and trace Ca-Mg-(Na). Reflux and bacterial activity could be suitable for the formation of dolomite. Deep burial diagenesis could have played an active role in the formation of ankerite and anhydrate. The continuous presence of halite suggested the paleo-lake water was highly brackish or saline, with high evaporation since 2.77 Ma. Salt layers in the lower 538.5 m-long sediments were present from 2221 ka to 2052 ka, corresponding to Pleistocene salt formation in the Qaidam Basin. As hydrated carbonate minerals, both gaylussite and the unnamed mineral are deposited under high precipitation rates with microbial activity. Gaylussite was deposited from Na-Ca-enriched solutions with molar ratios of Na/Ca more than 2 from 691 m (2226 ka) to 413.6 m (1222 ka). The un-named mineral (Mg0.92Ca0.08CO3 center dot 3H(2)O) was found from 523.4 m (1728 ka) to 724.2 m (2308 ka). Anhydrite could be transformed from gypsum under deep burial from 657.42 m (2052 ka) to 867 m (2556 ka). Alternating salt and clay layers in the lower part of the core recorded arid and relatively wet climatic oscillations and the evolution of brine. As a tectonic sub-basin, tectonic activities could change the local climate during episodes of uplift and subsidence. The dominant minerals in the Chahansilatu sub-basin are similar to those of the other sub-basins in the western Qaidam Basin, but have asynchronous evolutionary stages of brine.</p