Inequalities for estimative and predictive probabilities

Let μE be the estimative and μP the predictive measures for assessing Gaussian probabilities. It is shown for convex symmetric sets A that _μE(A) _μP(A) and that similar inequalities hold between members of a sequence of predictive measures. An application yields inequalities for generalized indices of atypicality associated with the two methods.     

Multistage index selection in finite populations

Multistage selection with fixed proportions and selection indices based on covariates of the target variable is studied. Assuming a multivariate normal distribution before the selection, expressions are presented for the expectation and the variance of the target variable in the retained subpopulation. As the numerical evaluation for finite populations requires lengthy computations, some approximations using methods for infinite populations are proposed. Numerical illustrations are given for selections in up to three stages.     

额窦同一认定的研究

本研究对额窦形态结构的观察,通过额窦的同一认定,进行个人识别;另一方面了解南方人的额窦形态结构特点,为法医人类学和法医放射学积累资料。从九个方面观察正位颅骨X光片的额窦形态结构;用22项形态特征指标对额窦进行描述,利用数字编码对额窦的指标进行评分。22项形态特征指标变异程度和个人识别率在0.46861—0.91120之间;22项指标累积变异程度和个人识别率为0.9999999999988,22项指标评分相同的概率为1.18366×10^-12,有7.5×10^11以上种组合形式。所有样本的22项指标组合评分不同。所观察的特征在不同个体间具有高度变异性,是进行个人识别的较好指标,本研究建立的这套观察指标和方法具有较好的个人识别能力。     

Progressive changes in the structure and dynamics of the phytoplankton community along a pollution gradient in a lowland river — a multivariate approach

The phytoplankton of the River Lujan (Buenos Aires, Argentina) was studied for a period of 18 months, together with physical and chemical variables, in relation to a pollution gradient. 167 taxa were recorded within a seasonal succession characterized by dominance of diatoms with a brief summer green algae facies. A combination of several biotic indices and multivariate analysis was employed to assess the impact of pollution on the phytoplankton community. The biotic indices used were species diversity and richness, algal quotients (green algae/diatom ratio, Centrales/Pennales ratio) and the SD succession rate index. Multivariate procedures included cluster analysis and ordination by PCA of both species and samples, stepwise discriminant analysis and multiple discriminant analysis of variance (MANOVA). Results indicate that community dynamism is attenuated at the more polluted sites, concomitant with an increased predominance of a broad-tolerance algal assemblage, co-dominated by Cyclotella meneghiniana and Nitzschia stagnorum. The changes in the community structure and dynamics described herein involved alterations in the distribution and relative proportions of the algae, rather than modifications in the basic species composition. These changes may not be readily detectable by methods which over-simplify the ecological information, such as systems of indicator species and biotic indices, designed to assess the degree of pollution. The suitability of multivariate analysis and biotic indices in river phytoplankton studies is further discussed.     

Reduced Personal Space in Individuals with Autism Spectrum Disorder

Maintaining an appropriate distance from others is important for establishing effective communication and good interpersonal relations. Autism spectrum disorder (ASD) is a developmental disorder associated with social difficulties, and it is thus worth examining whether individuals with ASD maintain typical or atypical degrees of social distance. Any atypicality of social distancing may impact daily social interactions. We measured the preferred distances when individuals with ASD and typically developing (TD) individuals approached other people (a male experimenter) and objects (a coat rack with clothes) or when other people approached them. Individuals with ASD showed reduced interpersonal distances compared to TD individuals. The same tendency was found when participants judged their preferred distance from objects. In addition, when being approached by other people, both individuals with ASD and TD individuals maintained larger interpersonal distances when there was eye contact, compared to no eye contact. These results suggest that individuals with ASD have a relatively small personal space, and that this atypicality exists not only for persons but also for objects.     

Biometeorological and autoregressive indices for predicting olive pollen intensity

This paper reports on modelling to predict airborne olive pollen season severity, expressed as a pollen index (PI), in Córdoba province (southern Spain) several weeks prior to the pollen season start. Using a 29-year database (1982–2010), a multivariate regression model based on five indices—the index-based model—was built to enhance the efficacy of prediction models. Four of the indices used were biometeorological indices: thermal index, pre-flowering hydric index, dormancy hydric index and summer index; the fifth was an autoregressive cyclicity index based on pollen data from previous years. The extreme weather events characteristic of the Mediterranean climate were also taken into account by applying different adjustment criteria. The results obtained with this model were compared with those yielded by a traditional meteorological-based model built using multivariate regression analysis of simple meteorological-related variables. The performance of the models (confidence intervals, significance levels and standard errors) was compared, and they were also validated using the bootstrap method. The index-based model built on biometeorological and cyclicity indices was found to perform better for olive pollen forecasting purposes than the traditional meteorological-based model.     

Do landscape health indices reflect arthropod biodiversity status in the eucalypt woodlands of eastern Australia?

Ecosystem or landscape health indices are important tools for land managers. While strong predictable relationships between these indices and biotic diversity are often generalized, they are seldom validated. Here we use data from a semi‐arid eastern Australian woodland to examine the relationships between arthropod community structure and two sets of landscape health indicators: landscape function analysis (LFA), and a terrestrial index of ecological integrity based on common vegetation metrics (structure, composition and function; SCF). Hierarchical partitioning revealed that the ability of LFA or SCF to account for variation in arthropod richness was low, with the variable of importance taxon‐dependent. Similarly, multivariate analyses indicated relatively weak and inconsistent relationships between LFA and SCF indices and arthropod assemblage structure. Results obtained for additional habitat attributes commonly used in terrestrial vegetation monitoring were similar. Our study indicates that strong predictable relationships are rarely apparent, particularly for arthropods. This indicates that these indices have limited use as surrogates of arthropod biodiversity. These results are contrary to the past literature, highlighting the need for additional research and the development of a conceptual and empirical framework linking health indices and arthropod biodiversity. This is necessary to further the theoretical and practical application of these measurements in environmental management.     

山东侧柏林生长生态特性的数值分析

应用多元分析方法研究了26个生态因子对山东侧柏林的3个生长指标的影响．结果表明影响林分生长的主要因子是：温度、土壤厚度、海拔和密度,排出了生态因子对林分生长指标的重要性序列,给出了林分生长指标的优化数学模型．     

How accurate are single site transect data for monitoring butterfly trends? Spatial and temporal issues identified in monitoring Lasiommata megera

Multiple transect counts following Butterfly Monitoring Scheme (UKBMS) guidelines and Jolly–Seber estimates of population size were used to monitor the abundance of second generation Lasiommata megera on a single site in southern England. The two methods resulted in different patterns of emergence being detected. The proportion of the population (estimated by Jolly–Seber) recorded with transect counts depended on the time of day and weather with afternoon transect counts best recording the trend in abundance over the flight period, but even then counts recorded a variable fraction of the population (6.2–51.3%). Increasing the frequency with which transect counts are carried out per week reduced variation and increased the fit of transect counts to Jolly–Seber generated population estimates. However, indices of abundance generated from randomly selected transect counts for L. megera within sampling weeks varied 4-fold and indices for other butterfly species were also highly variable. For L. megera, transect count variability is attributed to non-representative placement of the transect route and changes in the behaviour and spatial distribution in relation to population size and season. We suggest that transect counts need to be fully validated before the data are used to monitor changes of butterfly populations at individual sites.     

Distribution and ecology of myxomycetes in the high-elevation oak forests of Cerro Bellavista, Costa Rica

Myxomycetes associated with a high-elevation (>3000 m) oak forest in the Talamanca Range of Costa Rica were studied for 7 mo. Field collections were supplemented with collections obtained from moist chamber cultures prepared with samples of bark and ground litter of Quercus costaricensis. Various microenvironmental parameters including pH, substrate moisture and diameter, height above the ground and canopy openness were recorded for each field collection, whereas macroenvironmental data for temperature and precipitation were obtained from a meteorological station near the study area. Niche breadth and niche overlap indices were calculated to assess possible resource partitioning by myxomycetes. Thirty-seven species were recorded, including 11 new records for Costa Rica, eight for Central America and one for the neotropics. Both PCA and NMS multivariate analyses indicated that pH and height above the ground explained most of the observed variation, although substrate diameter also seemed to be an important factor. Precipitation showed an inverse correlation with the number of fruitings, confirming its importance as a macroenvironmental factor. Niche overlap values were not higher for closely related species and values for niche breadths were similar for most of the more common species, suggesting that most members of the assemblage of myxomycetes present in the study site are ecological generalists.     

Enhancing the performance and interpretation of freshwater biological indices: An application in arid zone streams

We assessed the performance of biological indices developed for invertebrate assemblages occurring in arid zone streams: a multimetric index (MMI) and an O/E index of taxonomic completeness. Our overall goal was to advance our understanding of the factors that affect performance and interpretation of biological indices. Our specific objectives were to (1) develop biological indices that are insensitive to natural environmental gradients, (2) develop a general method to determine if the biological potential of an assessed site is adequately represented by the population of reference sites, (3) develop a robust method to select metrics for inclusion in MMIs that ensures maximum independence of metrics, and (4) determine if a fundamental sample property (the evenness of taxa counts within a sample) affects index performance. Random Forest modeling revealed that both individual metrics and taxa composition were strongly associated with natural environmental heterogeneity, which meant both the MMI and O/E index needed to be based on site-specific expectations. We produced a precise, responsive, and ecologically robust MMI by using principal components analysis to identify 7 statistically independent metrics from a list of 31 candidate assemblage-level metrics. However, the O/E index we developed was relatively imprecise compared with O/E indices developed for other regions. This imprecision may be the consequence of low predictability in local taxa composition associated with the relatively high spatial isolation of aquatic habitats within arid regions. We were also able to assess the likelihood that the biological potential of assessed sites were adequately characterized by the population of reference sites by developing and applying a multivariate, nearest-neighbor test that determined if an assessed site occurred within the environmental space of the reference site network. This approach is robust and applicable to all biological indices. We also demonstrate that the evenness of taxa counts within a sample is positively related to estimates of sample taxa richness and thus the scores of both indices. The relationship between richness and sample evenness can potentially compromise inferences regarding biological condition, and post hoc adjustments for the effects of evenness on index scores might be desirable. Further improvements in the performance and interpretation of biological indices will require simultaneous consideration of the effects of incomplete sampling on characterization of biological assemblages and the physical and biological factors that influence community assembly.     

Multiple imputation in the presence of an incomplete binary variable created from an underlying continuous variable

Multiple imputation (MI) is used to handle missing at random (MAR) data. Despite warnings from statisticians, continuous variables are often recoded into binary variables. With MI it is important that the imputation and analysis models are compatible; variables should be imputed in the same form they appear in the analysis model. With an encoded binary variable more accurate imputations may be obtained by imputing the underlying continuous variable. We conducted a simulation study to explore how best to impute a binary variable that was created from an underlying continuous variable. We generated a completely observed continuous outcome associated with an incomplete binary covariate that is a categorized version of an underlying continuous covariate, and an auxiliary variable associated with the underlying continuous covariate. We simulated data with several sample sizes, and set 25% and 50% of data in the covariate to MAR dependent on the outcome and the auxiliary variable. We compared the performance of five different imputation methods: (a) Imputation of the binary variable using logistic regression; (b) imputation of the continuous variable using linear regression, then categorizing into the binary variable; (c, d) imputation of both the continuous and binary variables using fully conditional specification (FCS) and multivariate normal imputation; (e) substantive-model compatible (SMC) FCS. Bias and standard errors were large when the continuous variable only was imputed. The other methods performed adequately. Imputation of both the binary and continuous variables using FCS often encountered mathematical difficulties. We recommend the SMC-FCS method as it performed best in our simulation studies.     

CYBEST Model 4. Automated cytologic screening system for uterine cancer utilizing image analysis processing

CYBEST (Cyto-Biologic Electronic Screening System) utilizes image analysis technology for the automated prescreening of cervical cytology specimens. CYBEST Model 3, which includes a television scan system and automatic shading control, achieved our initial goal of rapid specimen processing (no more than three minutes to achieve a final specimen assessment). This paper describes CYBEST Model 4, developed in 1981; with the minicomputer of Model 3 replaced by a microcomputer, Model 4 is considerably smaller, about the size of a business desk. A new parameter, the intranuclear configuration (chromatin pattern), was added to the four parameters used in Model 3. The five parameters now used for the assessment and ranking of cytologic abnormalities are nuclear size, nuclear-cytoplasmic ratio, nuclear optical absorption, nuclear shape and intranuclear configuration. The other features of Model 4 are almost the same as those of Model 3. As an optional function, individual parameter measurement data, assessment of atypicality grade and cell images can be displayed on the CRT monitor by pointing to a cell with a light pen system. After completion of screening of a specimen, the ten cells judged to be most abnormal can be called automatically into the microscope optical field or the CRT monitor (in order ranging from the cell with the highest atypicality rank down) along with their associated data and the system's assessment of the specimen. By connection to a small business computer, all data can be transferred to a floppy disk for later retrieval.     

Response of epilithic diatom assemblages to urbanization influences

Urbanization has long been recognized to alter the hydrology, water quality and channel form of waterways. Recently, consideration of urban impacts on waterways has expanded to include assessment of the aquatic biota, generally focusing upon the macroinvertebrate fauna. This study compares the impacts of urbanization on the structure of stream benthic diatom communities in 16 first- and second-order streams in the east of Melbourne, Australia. Relationships between the physical elements of urbanization, water quality and diatom communities were examined using multivariate analyses with compositional similarity, and univariate analyses with selected diatom species and indices,. There was a strong negative correlation between urban density and the diatom indices of water quality. The element of urbanization most strongly related to the measured decline in the diatom community was drainage connection. Electrical conductivity was the most influential water quality variable. It is hypothesized that, in addition to increasing electrical conductivity, drainage connection may be impacting the diatom community by increasing the delivery of phosphorus during small storm events. The study suggests that reducing directly piped drainage connection using infiltration and retention is a logical step in the mitigation of urban impacts upon receiving streams. A corollary part of the project indicated strong potential for using overseas diatom indices in studies on water quality in southeastern Australia.     

Indices for monitoring biodiversity change: Are some more effective than others?

Statistically rigorous methods for summarizing and reporting trends in the intactness of biodiversity are a key element of effective biodiversity monitoring programs. There are four major approaches for translating complex monitoring data into easily communicated summary statistics: (1) traditional diversity indices such as species richness and Simpson's diversity, (2) species intactness indices based on occurrence, (3) species intactness indices based on abundance, and (4) multivariate community indices. We use simulated data to evaluate the effectiveness of 13 indices from these four categories based on statistical robustness, sensitivity to errors and noise in the data, ecological relevance, and ease of communication. We show that indices that calculate species intactness using equations like Buckland's arithmetic mean index are the most effective for use in large-scale biodiversity intactness monitoring programs. Traditional diversity indices are unsuitable for monitoring of biodiversity intactness, and multivariate indices can be highly sensitive to errors and noise in the data. Finally, we provide guidelines for the application of these indices in biodiversity intactness monitoring.     

Neandertal capitate-metacarpal articular morphology

Neandertal capitate-metacarpal 2 and 3 articulations have been observed to differ in orientation and shape from those of more recent humans. To evaluate this, we tested for differences in capitate-metacarpal 2 (MC2) and MC2-capitate facet orientations and MC2 and MC3 robusticity indices, and for multivariate shape equivalence of the capitate-MC2/MC3 facets and the MC3 diaphysis and styloid process between samples of Neandertals and recent humans. Canonical discriminant functions of log size-and-shape and log shape transformed measurements were run on variables of the capitate-MC2 and MC3 facets, and these plus MC3 diaphysis and styloid process variables. The null hypothesis of shape equivalence is rejected for both variable sets. Modern human capitate-MC morphology results from nonallometric increases in distal capitate breadth and the projection of the MC3 styloid process, and reductions in MC2 facet height and MC3 facet breadth. These shape changes are associated with a significantly less parasagittal orientation of the capitate-MC2 facets in recent humans, but are only trivially correlated with MC 2 and 3 robusticity indices. The recent human capitate-MC 2 and 3 morphology may reflect a shift in habitual joint reaction forces from more axial to more oblique forces while maintaining similar pronation/supination of the MC2. However, the full behavioral implications of these contrasts remain unclear. Am J Phys Anthropol 103:219–233, 1997. © 1997 Wiley-Liss, Inc.     

Factor and principal component analyses as alternatives to index selection

Summary Selections from factor and principal component analyses were compared with those from the Smith-Hazel index when selecting for several switchgrass (Panicum virgatum L.) traits. The objective of this study was to examine several alternatives to index selection. Such procedures would potentially eliminate problems of selection associated with Smith-Hazel indices, including errors in genetic parameter estimates and difficulty in assigning relative economic weights to traits. Selection was performed on 1,280 plants that were evaluated over 2 years at 1 location, in a randomized complete block design with 4 replicates. The plants were evaluated for forage yield and several forage quality traits. The comparisons of index selection with principal factor analysis, maximum-likelihood factor analysis and principal component analysis were made for three sets of traits (five traits per set) to estimate repeatability for the comparisons. Multivariate analyses were performed on both simple and genotypic correlation matrices. Comparisons were made by computing Spearman's rank correlations between selection index plant scores and scores computed from multivariate analysis and by determining the number of plants selected in common for the selection methods. Among the three multivariate analysis methods evaluated in this study, principal component analysis had the highest correlation with index selection. The high correlation for principal component analysis of simple correlation matrices indicates the potential for using this statistical method for selection purposes. This would permit the breeder to reduce field costs (e.g., time, labor, equipment) required to obtain the genetic parameter estimates necessary to construct selection indices.     

Exploring the dynamics of collective synchronizations in large ensembles of brain signals.

Developing methods characterizing the dynamics of synchronization in large ensemble of electromagnetic brain signals has become an important issue. In this article, we review a recently introduced method for analyzing multivariate phase synchronization in brain signals. The approach is based on the equivalence between phase locking and frequency locking in narrow band signals, which allows tracking multivariate phase synchronization in the time-frequency domain as periods of common frequency among multiple channels. The method is illustrated with simulations of multivariate phase dynamics in coupled oscillators and real multichannel electro- and magnetoencephalographic data recorded prior and during epileptic seizures. The reviewed results support the relevance of this method in the context of brain synchronization, in particular to track transient collective dynamics fluctuating in time, frequency and space.     

基于小波分析的大豆叶绿素a含量高光谱反演模型

 2003和2004年分别在长春市良种场和中国科学院海伦黑土生态实验站实测了大田耕作与水肥耦合作用下大豆（Glycine max）冠层高光谱反射率 与叶绿素a含量数据,对光谱反射率、微分光谱与叶绿素a含量进行了相关分析;采用归一化植被指数(Normalized diffe rence vegetation index, NDVI)、土壤调和植被指数(Soil-adjusted vegetation index, SAVI)、再归一植被指数(Renormalized difference vegetation index, RDVI)、第二修正比值植被指数(Modified second ratio index, MSRI)等建立了大豆叶绿素a反演模型;应用小波分析对采集的光谱反 射率数据进行了能量系数提取,并以小波能量系数作为自变量进行了单变量与多变量回归分析,对大豆叶绿素a进行了估算。研究结果表明,大 豆叶绿素a 与可见光光谱反射率相关性较好,并在红光波段取得最大值(R²>0.70),但在红边处,微分光谱与大豆叶绿素a的相关性较反射率好 得多,在其它波段则相反;由NDVI、SAVI、RDVI、MSRI等植被指数建立的估算模型可以提高大豆叶绿素a的估算精度（R²>0.75）;小波能量系 数回归模型可以进一步提高大豆叶绿素a含量的估算水平,以一个特定小波能量系数作为自变量的回归模型,大豆叶绿素a回归决定系数R²高达 0.78;多变量回归分析结果表明,大豆叶绿素a实测值与预测值的线性回归决定系数R²均高达0.85。以上结果表明, 小波分析可以对高光谱进 行特征变量提取,并可在一定程度上提高大豆生理参数反演精度。