A novel method for estimating the strength of positive mating preference by similarity in the wild

Mating preference can be a driver of sexual selection and assortative mating and is, therefore, a key element in evolutionary dynamics. Positive mating preference by similarity is the tendency for the choosy individual to select a mate which possesses a similar variant of a trait. Such preference can be modelled using Gaussian‐like mathematical functions that describe the strength of preference, but such functions cannot be applied to empirical data collected from the field. As a result, traditionally, mating preference is indirectly estimated by the degree of assortative mating (using Pearson's correlation coefficient, r) in wild captured mating pairs. Unfortunately, r and similar coefficients are often biased due to the fact that different variants of a given trait are nonrandomly distributed in the wild, and pooling of mating pairs from such heterogeneous samples may lead to “false–positive” results, termed “the scale‐of‐choice effect” (SCE). Here we provide two new estimators of mating preference (C_rough and C_scaled) derived from Gaussian‐like functions which can be applied to empirical data. Computer simulations demonstrated that r coefficient showed robust estimations properties of mating preference but it was severely affected by SCE, C_rough showed reasonable estimation properties and it was little affected by SCE, while C_scaled showed the best properties at infinite sample sizes and it was not affected by SCE but failed at biological sample sizes. We recommend using C_rough combined with the r coefficient to infer mating preference in future empirical studies.     

Kinetic characteristics of L-lysine α- oxidase from Trichoderma cf. aureoviride Rifai VKM F-4268D: Substrate specificity and allosteric effects

The present work aims to investigate the kinetic characteristics of homodimer enzyme L-lysine α-oxidase from Trichoderma cf. aureoviride Rifai VKM F-4268D, taking into account allosteric effects. The enzyme was first shown to reveal positive cooperativeness, h=2.05±0.15. Using additional opportunities of Hill coefficient the value of the Michaelis–Menten constant has been estimated, K_m=1.015?10^?5М, indicating high strength of substrate binding to the active site of each subunit. High selectivity and absolute L-stereospecificity of the enzyme were shown. The inhibition of L-lysine conversion by non-cleavable lysine analogs as well as the reaction product was found out to take place. These effects have been evaluated only as the inhibition coefficients (%). A more detailed study of these inhibition effects was complicated because of the cooperativeness of enzyme subunits mentioned above. The kinetic scheme of L-lysine α-oxidase was proposed involving parallel-subsequent action of each of two subunits in the catalytic act.We think that the results obtained will be useful for studying the kinetic properties of other multi-subunit enzymes and improve understanding of the mechanisms of their action.     

On the appearance of carboxylates in electrostatic potential maps

Electron microscopy can provide accurate, high‐resolution images of the distribution of electrostatic potential (ESP) in biological macromolecules. Careful examination of ESP maps that have been published for peptides and proteins at resolution ranging from 1.0 Å to 2.9 Å reveals that the negative charges of carboxylate groups have a profound effect on their appearance. It is clear that investigators must take the negative features in their experimental ESP maps into account when modeling the conformations of Asp and Glu side chains and those of the residues that surround them.     

Non‐invasive optical assessment of viscosity of middle ear effusions in otitis media

Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ability of a physician to accurately identify and characterize the middle ear for signs of fluid and/or infection is crucial to provide the most appropriate treatment for the patient. Currently, middle ear infections are assessed with otoscopy, which provides limited and only qualitative diagnostic information. In this study, we propose a method utilizing cross‐sectional depth‐resolved optical coherence tomography to noninvasively measure the diffusion coefficient and viscosity of colloid suspensions, such as a MEE. Experimental validation of the proposed technique on simulated MEE phantoms with varying viscosity and particulate characteristics is presented, along with some preliminary results from in vivo and ex vivo samples of human MEEs.

In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time‐lapse M‐mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes–Einstein diffusion coefficient of the effusion.     

Optimization of ultrasound-assisted aqueous two-phase system extraction of polyphenolic compounds from Aronia melanocarpa pomace by response surface methodology

Aronia melanocarpa berries are abundant in polyphenolic compounds. After juice production, the pomace of pressed berries still contains a substantial amount of polyphenolic compounds. For efficient utilization of A. melanocarpa berries and the enhancement of polyphenolic compound yields in Aronia melanocarpa pomace (AMP), total phenolics (TP) and total flavonoids (TF) from AMP were extracted, using ultrasound-assisted aqueous two-phase system (UAE-ATPS) extraction method. First, the influences of ammonium sulfate concentration, ethanol–water ratio, ultrasonic time, and ultrasonic power on TP and TF yields were investigated. On this basis, process variables such as ammonium sulfate concentration (0.30–0.35?g?mL^?1), ethanol–water ratio (0.6–0.8), ultrasonic time (40–60?min), and ultrasonic power (175–225?W) were further optimized by implementing Box–Benhnken design with response surface methodology. The experimental results showed that optimal extraction conditions of TP from AMP were as follows: ammonium sulfate concentration of 0.324?g?mL^?1, ethanol–water ratio of 0.69, ultrasonic time of 52?min, and ultrasonic power of 200?W. Meanwhile, ammonium sulfate concentration of 0.320?g?mL^?1, ethanol–water ratio of 0.71, ultrasonic time of 50?min, and ultrasonic power of 200?W were determined as optimum extraction conditions of TF in AMP. Experimental validation was performed, where TP and TF yields reached 68.15?±?1.04 and 11.67?±?0.63?mg?g^?1, respectively. Close agreement was found between experimental and predicted values. Overall, the present results demonstrated that ultrasound-assisted aqueous two-phase system extraction method was successfully used to extract total phenolics and flavonoids in A. melanocarpa pomace.     

基于净生产力生态足迹模型的工业碳排放效应、影响因素与情景模拟

以不同类型城市东营和滨州为例,采用基于净生产力的生态足迹模型测度2005—2014年两市工业碳排放效应,利用弹性系数模型对工业碳排放生态足迹及其影响因素进行对比,通过情景模拟分析了基准和低碳情景下两市的可持续低碳发展潜力。研究结果显示:(1)东营碳排放总量和碳排放强度明显高于滨州,两市的碳排放生态足迹总体上都处于上升趋势,年均增长率分别为12.79%和6.16%,这与两市工业化发展阶段不同有关;(2)2005—2008、2008—2011和2011—2014,东营工业碳排放生态足迹当量主导影响因素组合变化为"耕地面积-土地城镇化率-能源结构系数"转化为"耕地面积-人口规模-能源结构系数"到"耕地面积-人口规模-第二产业比重";滨州2005—2014年的主导因素组合一直为"人口规模-土地城镇化率-能源结构系数";(3)通过情景模拟分析2020年东营、滨州的低碳发展潜力:基准和低碳情景下,滨州生态赤字分别为东营的10倍和2.6倍;就"减排"潜力而言,滨州远远高于东营,但实现低碳情景是工业GDP增长从现阶段20.6%骤降到6.5%为代价,对产业结构调整升级要求很高。对东营而言,低碳情景的实现不仅要将能源利用效率提高一倍,更要保证大量重要"碳汇"资源的恢复与重建。     

Adsorption Characteristics and the Effect of Dissolved Organic Matter on Mercury(II) Adsorption of Various Soils in China

To evaluate the adsorption characteristics and effects of dissolved organic matter (DOM) from wheat straw (DOM_W) and swine manure (DOM_S) on mercury [Hg(II)] adsorption by soils, a series of experiments was conducted on 26 soils with different soil properties.Results showed that the values of K_d (a solid–liquid partition coefficient) of soils varied within a range of 0.768–14.386 L g^?1. K_d values were mainly controlled by soil organic matter (SOM), cation exchange capacity (CEC), soil nitrogen (N), and soil sulfur (S). When DOM_W and DOM_S were added to the soil samples, the amount of Hg(II) adsorbed by the soils decreased significantly. Furthermore, based on the decreased percentage of adsorption of Hg(II) by soil upon adding DOM_W (P_DOMW) or DOM_S (P_DOMS), about 73.08% soils, the values of P_DOMS were smaller than those of P_DOMW. The P_DOMW values were related to SOM, pH, free Fe oxide content, and CEC, whereas P_DOMS values were related to soil free Fe/Al oxide contents. Therefore, we should pay more attention about mercury risk caused by the addition of exogenous organic matter in soils, especially for the soils with low or high pH, less SOM, low CEC, and less free Fe/Al oxide.     

环境因子对常绿阔叶树种脱耦联系数及冠层气孔导度估算的影响

精确模拟冠层气孔导度(G_S)对于评估区域蒸散具有重要意义。该研究选择两种常见的人工阔叶树种尾叶桉(Eucalyptus urophylla, 外来种)和木荷(Schima superba, 本地种)作为研究对象, 利用K?stner法和修订的Penman-Monteith公式计算冠层平均气孔导度(分别定义为G_S1和G_S2)。研究还分析了环境因子对冠层脱耦联系数(Ω)的影响, 并用其来评价两种方法模拟的冠层气孔导度的合理性。结果表明, 两个树种冠层气孔导度均与气象条件耦合较好(尾叶桉: Ω = 0.10 ± 0.03, 木荷: Ω = 0.17 ± 0.03)。主成分分析显示, 光合有效辐射(PAR)以及水汽压亏缺(D)显著影响Ω的大小, 而风速(u)的影响较小。单因素分析则发现各环境因子与Ω之间的相关性并不显著。边界线分析表明D和PAR的增加使得Ω最终趋向于一个与树种有关的稳定值(木荷≈ 0.20, 尾叶桉≈ 0.05), 而Ω随u的增加呈幂指数下降。与木荷相比, 尾叶桉具有更高的气孔导度(尾叶桉和木荷的G_S2年平均值分别为(33.42 ± 9.37) mmol·m ^-2·s ^-1和(23.40 ± 2.03) mmol·m ^-2·s ^-1), 并且尾叶桉和木荷的G_S1与G_S2的线性拟合斜率分别为0.92 (R ² ≈ 0.70)和0.98 (R ² ≈ 0.76) , 表明G_S1比G_S2高估了冠层气孔导度。另外, G_S1和G_S2对水汽压亏缺的敏感性与参比气孔导度(G_Siref, D = 1 kPa时的气孔导度)的比值Pi与Ω紧密相关。根据统计, 尾叶桉和木荷的G_S1估计值在Ω = 0.05-0.15 (83.1%的数据)和0.10-0.20 (47.8%的数据)之间时是相对可靠的。     

内蒙古锡林郭勒草原大针茅-克氏针茅群落的种间关联特征分析

内蒙古锡林郭勒草原处于我国典型草原分布区, 但部分地区有戈壁针茅(Stipa gobica)等荒漠成分侵入, 并与大针茅(S. grandis)和克氏针茅(S. krylovii)共同形成斑块状格局分布, 目前尚不清楚群落中优势种之间的相互作用关系。采用2 × 2列联表, 通过方差分析、Pearson相关分析和Spearman秩相关分析等研究方法, 对大针茅+克氏针茅群落的大针茅斑块、克氏针茅斑块和戈壁针茅斑块中的24种主要植物的种间联结动态进行了定量分析。结果表明: 1)群落主要成分总体上种间联结呈无关联, 种间关联松散; 2) 3种针茅斑块的种间关联分析, 验证了由于干扰、竞争、土壤环境与植物相互作用形成的斑块分布格局, 此结果为种对正、负关联理论提供了有力证据; 3) 同一种对的联结性质(正关联或负关联)或关联程度因斑块不同而发生改变, 根据24个优势种群对环境的适应方式和主导生态因素, 可将它们划分为3大生态种组。     

内蒙古典型草原作物系数的动态模拟与确定

作物系数是计算作物需水量必不可少的参数。利用2008年野外水分试验和4个气象站近26年的土壤水分和气象等常规观测资料, 以相关分析和回归分析等统计学方法为基础, 根据水量平衡原理计算了内蒙古典型草原区的作物系数, 分析了其在生长期和不同站点间的变化规律; 建立了典型草原标准作物系数与返青后年日数和大于0 ℃积温的模拟方程, 相关指数在0.94以上。在分析湿润指数、叶面积指数和盖度与作物系数关系的基础上, 提出标准作物系数的气候修正方法和胁迫条件下作物系数的修正方法。同时, 与修正后的联合国粮农组织(FAO)推荐值比较后得出, 生长季标准作物系数的平均值为0.60, 最大值为1.02; 不同生长阶段作物系数的典型值分别为: 初始生长期0.40, 生长中期0.93, 生长后期0.80, 相应的阈值范围为0.35-0.45、0.85-1.00和0.70-0.90。通过旬蒸散量的模拟计算值与蒸渗仪实测结果的比较, 平均相对误差在20%-24%之间, 生长旺盛期大多低于10%, 从而初步证明该文提出的方法在内蒙古典型草原区有较好的适用性。