Search

This paper describes the study of the relationship between the thermal configuration of the Bay of Bengal (BOB)-Tibetan Plateau (TP) region and the precipitation anomaly in Yunnan, a province in China, in May using ERA-Interim data and precipitation data for May from 125 meteorological stations across Yunnan for 1979-2014. Results from the analysis indicate that the interannual variability of May precipitation in Yunnan is significantly modulated by the BOB-TP thermal configuration. Model runs with a linear baroclinic model suggest physical consistency. The thermal conditions over the BOB mainly impact the May precipitation anomaly in Yunnan via changes in water vapor transport from the eastern BOB northeastward to southwestern Yunnan. The second factor influencing precipitation anomalies relates to the characteristics and variability of cold air transport from the TP to northeastern Yunnan. When the BOB (the TP) is occupied by positive (negative) diabatic heating, a thermal gradient with a warmer (colder) center over the BOB and a colder (warmer) center over the TP is established, and more-than-normal (less than normal) precipitation in Yunnan will occur in May. This relationship can persist from April to the following May to some extent; therefore, the BOB-TP thermal configuration in April could be used to forecast May precipitation in Yunnan. [ABSTRACT FROM AUTHOR]

Two new species of Christisonia (Orobanchaceae), Christisonia hekouensis Gui L.Zhang, J.D.Ya & W.B.Yu and Christisonia dentosa J.D.Ya, Gui L.Zhang & W.B.Yu, found during botanical surveys in Southeast Yunnan, China, are described and illustrated. The two new species are similar to C. kwangtungensis bearing rose-red flowers and conspicuously inflated corolla tubes, and phylogenetic analyses strongly support the three species as monophyletic. However, C. hekouensis can be distinguished from C. kwangtungensis and C. dentosa by having externally puberulent calyces and corollas, corolla lobes with serrulate margins, styles that are pink and glabrous or sparsely capitate-glandular pubescent above, and with anthers less than 2 mm below the stigma. Christisonia dentosa differs from C. kwangtungensis and C. hekouensis by having dentate corolla lobe margins, internally capitate-glandular pubescent corollas, styles distinctly capitate-glandular pubescent above, and more than six anthers which are up to 10 mm below the stigma. [ABSTRACT FROM AUTHOR]

Background: Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province—which borders Myanmar—is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. Methods: We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July–October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. Results: Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4–3.9). Conclusions: A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens. [ABSTRACT FROM AUTHOR]

Potentially toxic metals in farmland soil have recently become a significant environmental concern in China. In this study, the occurrence and distribution of eight (8) heavy metals (HMs) were investigated from 54 topsoil samples obtained across 18 provinces. Human health and ecological hazards associated with HMs were assessed through different risk characterization indices and their sources predicted. The statistically mean concentrations of HMs ranged from 0.08 to 70.05 mg kg−1, which were below the determined threshold values for agricultural lands according to the Chinese National Standard (GB 15618–2018). The respective ecological risk index ( E r i) of HMs revealed that they posed a lower risk ( E r i < 40) but their potential cumulative ecological risk (RI) was determined as a considerable risk (300 ≤ RI < 600). Spatial distribution and heterogeneities of HMs were found to be highly concentrated in the southern parts (e.g., Yunnan, Guangdong) of China, particularly for Arsenic (As), Zinc (Zn), and Chromium (Cr). PMF model was found capable of efficiently elucidating respective sources of HMs across the studied provinces as most were impacted by geological/pedogenic and anthropogenic activities (e.g., agricultural, industrial discharge fallouts). Probabilistic health risk assessment indicated that the non-carcinogenic risk (NCR) and total carcinogenic risk (TCR) of HMs in both adults and children were low and acceptable. [Display omitted] [ABSTRACT FROM AUTHOR]

Rare earth elements and yttrium (REY) in coal, fly ash as well as coal preparation products have attracted much attention due to the increasing demand worldwide. In this paper, the distribution of REY in different size and density fractions, their mode of occurrence, and the insight they provide on the sediment source region of the Reshuihe coal in southern China are studied. The results show that the physical separation method caused light-REY (LREY) to be enriched in the low-density and large-sized coal particles, whereas medium-REY (MREY) and heavy-REY (HREY) are enriched in small-sized and high-density fractions. In addition, LREY are more closely associated with organic matter, while MREY and HREY occur more often in aluminosilicate minerals. Moreover, the sediment source of the Reshuihe coal was mainly derived from the felsic–intermediate rocks at the top of the Emeishan basalt sequence. Further, REY in the feed coal are generally not enriched, though REY are enriched in density fractions of 1.4 kg/L. The combustion products of coal with a density of 1.4 kg/L obtained by gravity separation have a potential economic value as promising raw materials for REY. • LREY (MREY and HREY) are enriched in the larger (smaller) size fractions with low (high) density grades. • LREY are more closely associated with organic matter, while MREY and HREY tend to occur in aluminosilicate minerals. • The combustion products of coals with a density of 1.4 kg/L have a potential economic value. [ABSTRACT FROM AUTHOR]

Mengzi locates in the south 20 km away from the outlet of Nandong subsurface river, and has been suffering from water deficiency in recent years. It is necessary to find out the water resources underground according to the geological characteristics such as the positions and buried depths of the underground river to improve the civil and industrial environments. Due to the adverse factors such as topographic relief, bare rocks in karst terrains, the geophysical approaches, such as Controlled Source Audio Magnetotellurics and Seismic Refraction Tomography, were used to roughly identify faults and fracture zones by the geophysical features of low resistivity and low velocity, and then used the mise-a-la-masse method to judge which faults and fracture zones should be the potential channels of the subsurface river. Five anomalies were recognized along the profile of 2.4 km long and showed that the northeast river system has several branches. Drilling data have proved that the first borehole indicated a water bearing channel by a characteristics of rock core of river sands and gravels deposition, the second one encountered water-filled fracture zone with abundant water, and the third one exposed mud-filled fracture zone without sustainable water. The results from this case study show that the combination of Controlled Source Audio Magnetotellurics, Seismic Refraction Tomography and mise-a-la-Masse is one of the effective methods to detect water-filled channels or fracture zones in karst terrains. [ABSTRACT FROM AUTHOR]

• The determination of element contents of Thelephora ganbajun by ICP-MS. • Chemometric approach have benn carried out, the LDA achieved high accuracy rate of 100 %. • Successfully discrimination of the samples by geographic origin. Geographical traceability is essential to the highly valued wild edible mushroom Thelephora ganbajun (T. ganbajun). This work examined the possibility of using the combination of multielement together with multivariate statistics methods, to identify the origins of 40 T. ganbajun from four sites of Yunnan province, China. Multielement analysis of thirteen elements (Mg, K, Ca, Al, Cr, Zn, As, Se, Cd, Pb, Fe, Mn, and P) were investigated by inductively coupled plasma mass spectroscopy (ICP-MS). Pearson correlation analysis was performed to check for the potential relationship between elements. Concentrations were used as chemical indicators to determine the geographical origins of T. ganbajun samples by utilizing multivariate data analysis, including principal component analysis (PCA), hierarchical cluster analysis (HCA), and linear discriminant analysis (LDA). Thirteen elements in T. ganbajun from different regions showed significant differences (p < 0.05), which proved that the elemental composition was an effective tool for distinguishing different origins of T. ganbajun. Classification of T. ganbajun using PCA gave satisfactory results, which permitted the reduction of 13 variables to three principal components explaining 92.84 % of the total variance. The HCA showed four clusters corresponding to the four origins of T. ganbajun. The LDA gave an overall correct classification rate of 100 % with an independent external sample set. These results revealed that multielement analysis combined with chemometrics is a useful tool for distinguishing T. ganbajun geographical origin. [ABSTRACT FROM AUTHOR]

• There is no standard for the ratio of SS:SA of the i n situ nylon bag technique(ISNBT) for the evaluation of ruminant feed and there are varying approaches used in China and around the world. • Increasing the ratio of sample size to nylon bag area (SS:SA) lowered the effective dry matter degradability of rye straw at SS:SA ratios of 29.17 and 37.5 mg/cm2. There was a trend for higher effective degradability (ED) at the lower SS:SA ratios for soybean meal crude protein. • These results show that with a standard nylon bag with external dimensions of 6 × 10 cm, increasing the amount of sample, thus raising the ratio of sample size to bag surface area (SS:SA ratio) reduces feed degradation. • Our recommendation is to operate at a SS:SA ratio of about 25 mg/cm2 for concentrate feed and a lower ratio (20 mg/cm2) for roughage. We thought that our work can accelerate the development of the standard of ISNBT. The in situ nylon bag technique (ISNBT) is traditional and necessary for the evaluation of ruminant feed, but there are exists some disunity operation schemes. Therefor, we select one way that varying SS:SA to determine the effects of it on feed degradation in the rumen. Eight Yunnan semi-fine wool sheep fitted with permanent ruminal cannul as were used and the nylon bags containing different sample size with fixed surface area. The results demonstrated that increasing the ratio of sample size to nylon bag area (SS:SA) lowered the effective dry matter (DM) degradability of rye straw. There was no difference in degradability with SS:SA ratios of 12.5 and 20.85 mg/cm2 but DM degradability was reduced (P < 0.05) at SS:SA ratios of 29.17 and 37.5 mg/cm2. At these higher SS:SA ratios DM degradability was also reduced (P < 0.05), at incubation durations of less than 36 h. A similar picture was obtained for rye straw crude protein (CP) degradability, although the effects of sample size and incubation time were less marked. In the case of the concentrated feedstuff, soybean meal, ruminal degradation was almost complete at 36 h and there was a trend for higher effective degradability (ED) at the lower SS:SA ratios. These results show that with a standard nylon bag with external dimensions of 6 × 10 cm, increasing the amount of sample, thus raising the ratio of sample size to bag surface area (SS:SA ratio) reduces feed degradation. It is recommended that sample size influenced feed degradation in the nylon bag technique and a sample weight of 2.5 g (SS:SA about 20 mg/cm2) should be used for evaluation of roughage and 3 g (SS:SA about 25 mg/cm2) for evaluation of concentrated diets for sheep using this technique. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the chemical composition of the perennial herb Inula hookeri collected from Weixi county, Yunnan Province, China in August 2010. The compounds from the herbs which were extracted, isolated and purified using silica gel, column chromatography (CC) yielded colorless and yellow oils, gums, amorphous powder and crystals.

• Two kinds of magnetite are identified at porphyry-related deposits in the Zhongdian region. • Some magnetite grains had undergone dissolution-reprecipitation processes. • The compositions of magnetite are affected by temperature, oxygen fugacity and hydrothermal alteration. The Zhongdian region in northwestern Yunnan (SW China) hosts a number of important porphyry and skarn deposits. In this study, we integrate petrographic observations, SEM-EDS elemental mapping, EPMA and LA-ICP-MS geochemical analyses on magnetite from several key deposits in the region. Magnetite grains from the Pulang porphyry Cu-Au, Lannitang porphyry Au-Cu, Langdu Cu skarn, Disuga porphyry, and andesite of Tumugou Formation were analyzed to unravel the magnetite formation mechanism, and the relative oxygen fugacity of the porphyry/skarn ore-related hydrothermal fluids in this region. Two types of magnetites (Magnetite I and II) have been identified. Magnetite I is commonly distributed in the chlorite and/or sericite alteration zone(s). Magnetite I grains are characterized by being textually inhomogeneous. The Magnetite I core (with local ilmenite exsolution lamellae) is Ti-Cr rich, indicative of a dominantly igneous origin. The Magnetite I core and its surrounding primary igneous minerals (biotite, amphibole and plagioclase) underwent late alteration. Magnetite I grains are characterized by core-rim texture, sharp core-rim contact, and irregular grain boundaries. These textural features indicate that Magnetite I may have undergone dissolution-reprecipitation processes, during which the Magnetite I core was chemically purified via losing Ti and gaining Fe. Magnetite II (in potassic and sericite alteration zones) is textually homogeneous with relatively low contents of Ti, Mg, Al, V, Ni, and Mn. We suggest that Magnetite II was formed by hydrothermal alteration. Compared to Magnetite II grains from the Pulang and Langdu deposits, those from the Lannitang deposit have lower Mn and V but higher Sn contents, indicative of higher oxygen fugacity of the hydrothermal fluids. We propose that binary plots such as Ti vs. Sc, V vs. Sn and Ga vs. Sn can distinguish the different origins of magnetites. From an exploration perspective, Magnetite II from the altered Disuga porphyries has similar texture and composition to its counterpart from the potassic-altered Pulang porphyries. This, together with the presence of Cu-sulfide inclusions in the Disuga Magnetite I, suggests significant mineralization potential in these porphyries. [ABSTRACT FROM AUTHOR]