Distribution,community characteristics and classification of Stipa tianschanica var. klemenzii steppe in China

Stipa tianschanica var. klemenzii steppe is the most typical formation of desert steppe in China. Based on the primary plots data obtained from fieldworks during the growing seasons from 2010 to 2016 as well as some earlier records, we studied the Stipa tianschanica var. klemenzii steppe across China systematically, including the eco-geographical distributions, community characteristics and classifications. The results showed that S. tianschanica var. klemenzii steppe distributed mainly on the Ulan Qab Plateau and western Xilin Gol Plateau. Due to the arid biotope of S. tianschanica var. klemenzii steppe, quantitative characteristics of the assemblage including height, coverage, biomass and species richness were normally lower than that of most Stipa formations in Eurasian steppe region. Moreover, 165 seed plants belonging to 85 genera and 29 families were recorded in the 80 study sites, in which rare species (occurrence frequency <20%) made up 87% of the total plants while common species and constant species could only be found occasionally. Species with the occurrence frequency exceeding 50% included S. tianschanica var. klemenzii, Convolvulus ammannii, Cleistogenes songorica, Allium tenuissimum. In addition, Hemicryptophyte and therophyte were the two dominant life forms, covering 55% and 20% of the species, respectively. As for the ecological type of water, typical xerophytes accounted for 47% of all species which is followed by super-xerophytes and meso-xerophytes. Middle Asian areal-type and east Palaeo-North areal-type were the two major floristic elements, containing 37% and 26% of the species, respectively. Based on the life forms and dominances of the species within the community, S. tianschanica var. klemenzii steppe in China could be classified into 6 association groups, 29 associations.     

北京市通州区冬季流感样病例病毒病原谱特征分析

目的了解北京市通州区冬季流感样病例病毒病原谱特征,为制定科学有效的防控措施提供依据。方法采用多重实时荧光PCR法,对2016年11月-2017年2月采集的265份流感样病例的咽拭子样本,检测人流感病毒、副流感病毒、人偏肺病毒、博卡病毒、人冠状病毒、呼吸道合胞病毒、鼻病毒、腺病毒的核酸。结果本次检测中,任一病毒阳性率为36.60%,其中单一病毒感染占96.91%,混合感染占3.09%。单一病毒感染中,人流感病毒检出率最高(31.70%),其次为鼻病毒(2.26%)。2016年11月-2017年2月,不同月份病毒的总检出率差异无统计学意义(χ~2=1.780,P=0.619)。从年龄组成看,不同年龄组人群病毒的总检出率差异无统计学意义(χ~2=1.691,P=0.639),19~60岁组人群检出的病毒种类多于其他年龄组。结论 2016年11月-2017年2月,北京市通州区引起流感样病例的病毒并非只有流感病毒,也有鼻病毒、偏肺病毒、腺病毒等其他常见呼吸道病毒,建议加强常见呼吸道病毒的监测。     

乌司他丁联合痰清宁雾化吸入对重症肺炎患者肌钙蛋白水平及心肌酶谱的影响

目的:探讨乌司他丁联合痰清宁雾化吸入对重症肺炎患者肌钙蛋白水平、心肌酶谱的影响。方法:收集2014年3月至2016年3月于我院治疗的104例重症肺炎患者,52例行常规治疗患者作为对照组,52例于常规治疗基础上行乌司他丁联合痰清宁雾化吸入患者作为观察组,比较两组体征及症状消失时间、肌钙蛋白[心肌肌钙蛋白T(cTnT)、心肌肌钙蛋白I(cTnI)]、心肌酶谱[谷草转氨酶(AST)、乳酸脱氢酶(LDH)\氢丁酸脱氢酶(HBDH)、肌酸激酶同工酶(CK-MB)]、临床症状积分、临床疗效及不良反应的发生情况。结果:观察组体征及症状消失时间明显短对照组(P0.05);治疗后,观察组cTnT、cTnI低于对照组,差异有统计学意义(P0.05);观察组AST、LDH、HBDH、CK-CB低于对照组,差异有统计学意义(P0.05);观察组临床症状积分低于对照组(P0.05);观察组有效率96.15%高于对照组82.69%(P0.05);两组不良反应发生率比较无统计学差异(P0.05)。结论:乌司他丁联合痰清宁雾化吸入治疗重症肺炎的临床疗效好,且可有效降低肌钙蛋白及心肌酶谱水平,减轻心肌损伤。     

Trace elements in rock salt and their bioavailability estimated from solubility in acid

In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded.     

FTIR and Raman Spectra Compared with Ab Initio Calculated Frequency Modes for 5-Aminouracil

Infrared (IR) and Raman spectra of 5-aminouracil were recorded in the region 200–4,000 cm^− 1. Assuming under the C_s point group that the distribution of the normal mode of vibrations between the two species are planar (a′) and non-planar (a″), given by 25a′ + 11a″ of which 30 modes (21a′ + 9a″) correspond to the uracil moiety and six modes (4a′ + 2a″) correspond to the NH₂ group, with a comparison of theoretically ab initio calculated frequencies, the results are in reasonably good agreement with the experimental IR and Raman spectra. Consistent assignments have been made for the internal modes of the NH₂ group, especially for the anti-symmetric NH₂ stretching and bending modes. The non-equivalence of the two NH bonds of the NH₂ group suggests a difference in the strength of the two hydrogen bonds on the pyrimidine ring. Symmetry and anti-symmetry NH stretching modes of the NH₂ group show the invalidity of the empirical relationship. These two NH₂ stretching frequencies are distinctly separated from the CH/NH ring stretching frequencies. A strong and sharp IR band that acts at 3,380 cm^− 1 could be identified as the anti-symmetric NH₂ mode whereas the band at 3,290 cm^− 1 smaller density could be identified as the symmetric NH₂ stretching mode.     

Trait coordination and environmental filters shape functional trait distributions of forest understory herbs

1. Understanding the drivers of trait selection is critical for resolving community assembly processes. Here, we test the importance of environmental filtering and trait covariance for structuring the functional traits of understory herbaceous communities distributed along a natural environmental resource gradient that varied in soil moisture, temperature, and nitrogen availability, produced by different topographic positions in the southern Appalachian Mountains.
2. To uncover potential differences in community‐level trait responses to the resource gradient, we quantified the averages and variances of both abundance‐weighted and unweighted values for six functional traits (vegetative height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, and leaf δ¹³C) using 15 individuals of each of the 108 species of understory herbs found at two sites in the southern Appalachians of western North Carolina, USA.
3. Environmental variables were better predictors of weighted than unweighted community‐level average trait values for all but height and leaf N, indicating strong environmental filtering of plant abundance. Community‐level variance patterns also showed increased convergence of abundance‐weighted traits as resource limitation became more severe.
4. Functional trait covariance patterns based on weighted averages were uniform across the gradient, whereas coordination based on unweighted averages was inconsistent and varied with environmental context. In line with these results, structural equation modeling revealed that unweighted community‐average traits responded directly to local environmental variation, whereas weighted community‐average traits responded indirectly to local environmental variation through trait coordination.
5. Our finding that trait coordination is more important for explaining the distribution of weighted than unweighted average trait values along the gradient indicates that environmental filtering acts on multiple traits simultaneously, with abundant species possessing more favorable combinations of traits for maximizing fitness in a given environment.

     

Interacting forces of predation and fishing affect species’ maturation size

1. Fishing is a strong selective force and is supposed to select for earlier maturation at smaller body size. However, the extent to which fishing‐induced evolution is shaping ecosystems remains debated. This is in part because it is challenging to disentangle fishing from other selective forces (e.g., size‐structured predation and cannibalism) in complex ecosystems undergoing rapid change.
2. Changes in maturation size from fishing and predation have previously been explored with multi‐species physiologically structured models but assumed separation of ecological and evolutionary timescales. To assess the eco‐evolutionary impact of fishing and predation at the same timescale, we developed a stochastic physiologically size‐structured food‐web model, where new phenotypes are introduced randomly through time enabling dynamic simulation of species'' relative maturation sizes under different types of selection pressures.
3. Using the model, we carried out a fully factorial in silico experiment to assess how maturation size would change in the absence and presence of both fishing and predation (including cannibalism). We carried out ten replicate stochastic simulations exposed to all combinations of fishing and predation in a model community of nine interacting fish species ranging in their maximum sizes from 10 g to 100 kg. We visualized and statistically analyzed the results using linear models.
4. The effects of fishing on maturation size depended on whether or not predation was enabled and differed substantially across species. Fishing consistently reduced the maturation sizes of two largest species whether or not predation was enabled and this decrease was seen even at low fishing intensities (F = 0.2 per year). In contrast, the maturation sizes of the three smallest species evolved to become smaller through time but this happened regardless of the levels of predation or fishing. For the four medium‐size species, the effect of fishing was highly variable with more species showing significant and larger fishing effects in the presence of predation.
5. Ultimately our results suggest that the interactive effects of predation and fishing can have marked effects on species'' maturation sizes, but that, at least for the largest species, predation does not counterbalance the evolutionary effect of fishing. Our model also produced relative maturation sizes that are broadly consistent with empirical estimates for many fish species.

     

Evaluation of Systematic Position of Helicoprorodontids and Chaeneids (Ciliophora,Litostomatea): An Attempt to Break Long Branches in 18S rRNA Gene Phylogenies

Phylogenetic position of some free‐living litostomatean taxa has not been correctly determined because of long‐branch artifacts in 18S rRNA gene trees. The main aim of this study was to test the effectiveness of various masking algorithms, tree‐building techniques, binarization of DNA data as well as combining morphological and molecular data to eliminate long‐branch attraction of two problematic groups, helicoprorodontids and chaeneids. Guidance and SlowFaster masking in a combination with PhyloBayesian tree construction erased the artifactual positions of helicoprorodontids and chaeneids. On the other hand, binarization of DNA sequences and the strategy of combining morphological and molecular data eliminated only the artifactual position of chaeneids but not that of helicoprorodontids which were still being attracted by out‐group taxa. According to statistical tree topology tests and comparative morphological studies, helicoprorodontids are classified as a distinct order while chaeneids are considered to be fast evolving members of the order Lacrymariida. The high body contractility, “cephalization” of the anterior body end, and helicalization of the anterior portion of some or all somatic ciliary rows indicate relatedness of helicoprorodontids, chaeneids, and lacrymariids. On the other hand, the dorsal brush separated from the circumoral kinety by dense ciliary files supports kinships of chaeneids, lacrymariids, and didiniids.