Testing different 3D techniques using geometric morphometrics: Implications for cranial fluctuating asymmetry in humans

This study aimed to test the performance of 3D digitizer, CT scanner, and surface scanner in detecting cranial fluctuating asymmetry. Sets of 32 landmarks (6 in the midline and 13 bilateral) were acquired from 14 archeological crania using a 3D digitizer, and from 3D models generated from a CT scanner and surface scanner using Viewbox 4. Levels of shape variation were analyzed in MorphoJ using Procrustes analysis of variance and Principal component analysis. Intra-observer error accounted for 1.7%, 1.8%, and 4.5% of total shape variation for 3D digitizer, CT scanner, and surface scanner respectively. Fluctuating asymmetry accounted for 15%–16% of total shape variation. Variation between techniques accounted for 18% of total shape variation. We found a higher level of missing landmarks in our surface scan data than for both 3D digitizer and CT scanner data, and both 3D model-based techniques sometimes obscured taphonomic damage. All three 3D techniques are appropriate for measuring cranial fluctuating asymmetry. We advise against combining data collected with different techniques.     

Variable selection in nonlinear function-on-scalar regression

We develop a new method for variable selection in a nonlinear additive function-on-scalar regression (FOSR) model. Existing methods for variable selection in FOSR have focused on the linear effects of scalar predictors, which can be a restrictive assumption in the presence of multiple continuously measured covariates. We propose a computationally efficient approach for variable selection in existing linear FOSR using functional principal component scores of the functional response and extend this framework to a nonlinear additive function-on-scalar model. The proposed method provides a unified and flexible framework for variable selection in FOSR, allowing nonlinear effects of the covariates. Numerical analysis using simulation study illustrates the advantages of the proposed method over existing variable selection methods in FOSR even when the underlying covariate effects are all linear. The proposed procedure is demonstrated on accelerometer data from the 2003–2004 cohorts of the National Health and Nutrition Examination Survey (NHANES) in understanding the association between diurnal patterns of physical activity and demographic, lifestyle, and health characteristics of the participants.     

Functional data analysis with covariate-dependent mean and covariance structures

Functional data analysis has emerged as a powerful tool in response to the ever-increasing resources and efforts devoted to collecting information about response curves or anything that varies over a continuum. However, limited progress has been made with regard to linking the covariance structures of response curves to external covariates, as most functional models assume a common covariance structure. We propose a new functional regression model with covariate-dependent mean and covariance structures. Particularly, by allowing variances of random scores to be covariate-dependent, we identify eigenfunctions for each individual from the set of eigenfunctions that govern the variation patterns across all individuals, resulting in high interpretability and prediction power. We further propose a new penalized quasi-likelihood procedure that combines regularization and B-spline smoothing for model selection and estimation and establish the convergence rate and asymptotic normality of the proposed estimators. The utility of the developed method is demonstrated via simulations, as well as an analysis of the Avon Longitudinal Study of Parents and Children concerning parental effects on the growth curves of their offspring, which yields biologically interesting results.     

豚鼠耳蜗电图慢成分的研究

选用0.8-150Hz的带通滤波,从豚鼠圆窗记录出一负一正相慢电位.实验结果表明.其对0.5kHz短音的反应阈为729dB nHL.较耳蜗电图快成分低38.27dB nHL.通过离断听觉传导径路不同水平对该电位的观察,表明它是毛细胞及听神经电反应的慢成分.而且可能受听觉传出神经的调控.     

5个番石榴品种果实食用品质和香气特征分析

为比较番石榴(Psidium guajava)不同品种果实的外观、营养价值和香气特征,采用国家标准方法,对5个番石榴品种(‘红宝石’、‘粉红蜜’、‘西瓜’、‘水蜜’、本地种)果实的外观和营养成分进行测定,采用顶空气质联用(HS-GC-MS)技术对5个品种果实的香气成分进行测定。结果表明,不同品种果实外观及营养成分差异明显。‘水蜜’的果形指数最低,果实扁圆形,种籽最少;大多数糖类物质(总糖、还原糖、蔗糖等)、糖酸比、总酚含量最高;果糖、VC和总黄酮含量位居第2;总酸、脂肪、粗纤维、灰分含量最低。主成分分析表明,‘水蜜’作为鲜食水果的食用品质最高。己醛和石竹烯是红肉型品种的特征风味物质,3-羟基-2-丁酮是白肉型品种的特征香气成分。     

Insecticidal and Repellent Effects of the Essential Oils Extract from Zanthoxylum myriacanthum against Three Storage Pests

The co-storage of two or more Chinese herbal medicines can effectively prevent the herbs from the damage by pests. Thus, it is important to protect herbs and crops to study Chinese herbal medicines and their medicinal components against storage pests. This study aimed to assess the insecticidal activities and repellent effect of essential oils (EOs) extracted from fruits at different periods from Zanthoxylum myriacanthum Wall. ex Hook. f. (1 h, 2 h, 3–5 h and 5–7 h), and their major compounds against three kinds of pests (Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila). The results of gas chromatography-mass spectrometer analysis revealed homomyrtenol (22.56 %, 28.01 %, 28.48 % and 28.41 %, respectively) and p-cymene (30.58 %, 13.95 %, 24.97 % and 6.85 %, respectively) were the common major compounds of the EOs at 1 h, 2 h, 3–5 h, and 5–7 h. m-Cymene contents in EOs of fruits, 1 h, 2 h and 3–5 h were 3.85 %, 0.95 %, 6.71 %, and 6.15 %, respectively. According to Principal component analysis (PCA), the composition of fruits′ EO was significantly different from other EOs due to the different collection times. The bio-assays showed that EOs and major compounds were toxic to all three pests, but the fumigation effect on L. bostrychophila was not noticeable. EOs extracted at different times had a repellent effect on the three pests at the highest concentration (78.63 nL/cm²), but the attractive effects of the EOs of 3–5 h, 5–7 h, and p-cymene were observed at the low concentrations (3.15, 0.63 and 0.13 nL/cm²). Our results suggest that Z. myriacanthum have the potential to be developed as biological insecticides.     

多元方差分析中的单一自由度独立比较

本文根据一元方差分析的单一自由度比较原理提出了多元方差分析中的单一自由度比较方法,以用于各种平衡试验设计中具多个变量的处理间多重比较．     

巢式设计的多元分析

本文把经典巢式设计的统计分析方法由单变量推广到多变量,使得试验或调查的多性状数据能综合在一起进行分析,以得出考虑了性状间相关性在内的统计结论并用一烟草栽培试验数据示明具体步骤。     

Measures of nematode community structure and sources of variability among and within agricultural fields

Whole nematode communities, extracted from soil samples taken from agricultural fields, were enumerated by taxonomic family and trophic group (i.e., bacterivores, fungivores, omnivores, plant-parasites, and predators) to evaluate nematode community structure as an indicator for monitoring ecological condition of soil. No differences were found in mixing treatments or methods of packing or shipping samples. However, extraction using Cobb's sifting and gravity method, followed by sucrose centrifugation, gave greater recovery of free-living nematodes than elutriation followed by sucrose centrifugation. Population means and variance of the sampled area were similar when sampled using different strategies for collecting soil samples within fieds, including several patterns, directions and repetitions of transects. Components of variation associated with ratios among the five trophic groups of nematodes and selected indices of community structure were quantified as variation among regions, among counties, among agricultural fields (2-ha area), among transects within agricultural fields, and within composite soil samples. The variance component for'within composite soil samples' was relatively large compared to the other components of variance. Variation within composite soil samples was less for maturity indices (based on life-history strategy characteristics), ratio of bacterivores to plant-parasites, sum of bacterivores and fungivores, populations of plant-parasites, and populations of bacterivores than for trophic diversity indices, populations of fungivores, populations of omnivores, populations of predators, or the ratio of fungivores to bacterivores. With a single composite sample per field, the ability to differentiate ecological condition of soils among fields within a region improved if the variance among and within fields exceeded the variance within composite samples. Given the variance components, power curves indicated that detection of a 10% change (with 0.8 power) in the ecological condition of soils within a region between two time periods would require sampling a minimum of 25 and 50 fields with one composite soil sample analyzed per field for the maturity and trophic diversity index, respectively. More than 100 fieldsper region would be required to detect temporal change in populations of individual trophic groups. Biplots of maturity indices, but not of trophic diversity or populations of individual trophic groups, identified clear differences among fields. Thus, maturity indices, which differentiated among sampling sites better and more efficiently than trophic diversity indices or measures based on populations of individual trophic groups, may be appropriate for use in a regional and/or national monitoring program.