Identification of the determinants of host resistantce and pathogenicity in interactions between Alternaria linicola Groves & Skolko and Linum Usitatissiumum L. accessions using multivariate analyses

Multivariate analysis of variance (MANOVA) and canonical variates analysis (CVA) were used to examine differences in host plant resistance and pathogen behaviour in interactions between Altemaria linicola and three genotypes of Linum usitatissimum, previously identified as susceptible, moderately resistant and resistant to the pathogen. Significant differences in pathogen development were found among the Linum accessions at 18, 24, and 40 h after inoculation. At 18 h after inoculation attempted penetration by the pathogen was relatively rare on all three accessions and canonical variates analysis revealed that overall differences among accessions resulted from large differences with respect to a small number of variables associated with successful penetration on the most susceptible accession. At later times after inoculation, when attempted penetration was more common, overall differences among accessions were found to result from smaller absolute differences among a group of variables which characterised the early colonisation of the host tissue. The results from these investigations are discussed in relation to recent research on the ecology of the pathogen and the importance of the timing of host responses to infection in determining host plant resistance.     

Detecting taxonomic signal in an under-utilised character system: geometric morphometrics of the forcipular coxae of Scutigeromorpha (Chilopoda)

To date, the forcipules have played almost no role in determining the systematics of scutigeromorph centipedes though in his 1974 review of taxonomic characters Markus Würmli suggested some potentially informative variation might be found in these structures. Geometric morphometric analyses were used to evaluate Würmli's suggestion, specifically to determine whether the shape of the forcipular coxa contains information useful for diagnosing species. The geometry of the coxae of eight species from the genera Sphendononema, Scutigera, Dendrothereua, Thereuonema, Thereuopoda, Thereuopodina, Allothereua and Parascutigera was characterised using a combination of landmark- and semi-landmark-based sampling methods to summarize group-specific morphological variation. Canonical variates analysis of shape data characterizing the forcipular coxae indicates that these structures differ significantly between taxa at various systematic levels. Models calculated for the canonical variates space facilitate identification of the main shape differences between genera, including overall length/width, curvature of the external coxal margin, and the extent to which the coxofemoral condyle projects laterally. Jackknifed discriminant function analysis demonstrates that forcipular coxal training-set specimens were assigned to correct species in 61% of cases on average, the most accurate assignments being those of Parascutigera (Parascutigera guttata) and Thereuonema (Thereuonema microstoma). The geographically widespread species Thereuopoda longicornis, Sphendononema guildingii, Scutigera coleoptrata, and Dendrothereua linceci exhibit the least diagnostic coxae in our dataset. Thereuopoda longicornis populations sampled from different parts of East and Southeast Asia were significantly discriminated from each other, suggesting that, in this case, extensive synonymy may be obscuring diagnosable inter-species coxal shape differences.     

Goodness of Fit of Discriminant Functions from the Vector Space of Fixed Variates

Alternative proofs of some of KSHIRSAGAR's (1971) results on testing discriminant functions or canonical variables in the vector space of fixed variates are given. These results are derived in terms of the original variates unlike KSHIRSAGAR (1971) who derives the results by using random orthogonal transformations and triangular decompositions of the original matrix variates.     

Detecting cryptic speciation in the widespread and morphologically conservative carpet chameleon (Furcifer lateralis) of Madagascar

Species delimitation within recently evolved groups can be challenging because species may be difficult to distinguish morphologically. Following the General Lineage Concept, we apply a multiple evidence approach to assess species limits within the carpet chameleon Furcifer lateralis, which is endemic to Madagascar and exported in large numbers for the pet trade. Cryptic speciation within F. lateralis was considered likely because this species (1) has a vast distribution, (2) occupies exceptionally diverse habitats and (3) exhibits subtle regional differences in morphology. Phylogenetic trees reconstructed using nuclear and mitochondrial genes recovered three well-supported clades corresponding with geography. Morphological results based on canonical variates analysis show that these clades exhibit subtle differences in head casque morphology. Ecological niche modelling results found that these phylogenetic groups also occupy unique environmental space and exhibit patterns of regional endemism typical of other endemic reptiles. Combined, our findings provide diverse yet consistent evidence for the existence of three species. Consequently, we elevate the subspecies F. lateralis major to species rank and name a new species distributed in northern and western Madagascar. Initial ecological divergence, associated with speciation of F. lateralis in humid eastern habitat, fits the Ecographic Constraint model for species diversification in Madagascar. By contrast, the second speciation event provides some support for the Riverine Barrier model, with the Mangoky River possibly causing initial isolation between species. These findings thus support two contrasting models of speciation within closely related species and demonstrate the utility of applying a combined-evidence approach for detecting cryptic speciation.     

Two auxiliary variates in ratio method of estimation

A ratio type estimator using two auxiliary variates has been proposed and conditions are obtained to choose between proposed estimator and OLKIN'S (1958) estimator using two auxiliary variates.     

Limnological characteristics of lakes located across arctic treeline in northern Russia

Limnological data (e.g., water chemistry, lakewater temperature, vegetation zone and degree of human impact) were collected from lakes spanning the Russian arctic treeline in three regions: on the Taimyr Peninsula and near the mouth of the Lena River, both in central arctic Siberia, and near the mouth of the Pechora River, western arctic Russia. Pearson correlation and canonical variates analyses revealed similar environmental gradients in all three regions. Variables expressing ionic composition of the water (i.e., cations, anions, dissolved inorganic carbon and conductivity) were highly intercorrelated, as were nutrients, chlorophyll a, particulate organic matter and metal (i.e., Fe and Mn) concentrations. Lakewater transparency was related to water colour (i.e., Fe, Mn and dissolved organic carbon) and productivity. Regional differences among the lakes were strong and appeared to reflect differences in geology, hydrology and human impact. For example, Na and Cl concentrations were related to proximity to the ocean in the Lena and Pechora River regions but not in the more inland Taimyr region. Extensive mining and smelting at Norilsk, on the Taimyr Peninsula, has apparently resulted in elevated major ion and metal concentrations in lakes closer to the city. Surface water temperatures, nutrients, and related variables were particularly useful for distinguishing lakes in different vegetation biomes. Forest lakes were typically warmer, with slightly elevated concentrations of dissolved organic carbon (DOC). Lakes in the forest–tundra zone often had higher concentrations of particulate organic matter, Fe and Mn. Tundra lakes were characterized by low nutrient and DOC concentrations. These data will facilitate the development of models that predict the outcome of future climatic change on arctic and subarctic aquatic ecosystems, as well as provide baseline data for future limnological studies in these remote regions.     

On Two Auxiliary Variates in Ratio Method of Estimation

A ratio type estimator using two auxiliary variates is suggested which is found to be more practicable than that of AGARWAL'S (1980) estimator.     

Size and shape in similarity coefficients based on metric characters

A variety of quantitative measures of distance and similarity have been used in physical anthropology, often without sufficient prior testing of their usefulness and understanding of their meaning. A variety of such coefficients were compared by applying them to an odontometric sample. It was found that Penrose's size-shape dichotomy extends not only to his coefficients but to all other similarity measures as well, such as the coefficient of racial likeness, generalized distance, canonical variates, and Q-mode correlation. Only size differences were detected by the C.R.L., Penrose's size distance, D², and canonical variates, and as a result these methods failed to produce an accurate classification. Penrose's shape distance and Q-mode correlation coefficients produced better results due to their determination of similarity on the basis of more important shape and morphological differences. The D² and canonical variates methods were converted to shape measures through Q-mode standardization of the raw data, whereupon they also produced more meaningful results.     

Sparse canonical correlation analysis for identifying, connecting and completing gene-expression networks

Background  

We generalized penalized canonical correlation analysis for analyzing microarray gene-expression measurements for checking completeness of known metabolic pathways and identifying candidate genes for incorporation in the pathway. We used Wold's method for calculation of the canonical variates, and we applied ridge penalization to the regression of pathway genes on canonical variates of the non-pathway genes, and the elastic net to the regression of non-pathway genes on the canonical variates of the pathway genes.     

Dedicated biomass crops can enhance biodiversity in the arable landscape

Suggestions that novel, non‐food, dedicated biomass crops used to produce bioenergy may provide opportunities to diversify and reinstate biodiversity in intensively managed farmland have not yet been fully tested at the landscape scale. Using two of the largest, currently available landscape‐scale biodiversity data sets from arable and biomass bioenergy crops, we take a taxonomic and functional trait approach to quantify and contrast the consequences for biodiversity indicators of adopting dedicated biomass crops on land previously cultivated under annual, rotational arable cropping. The abundance and community compositions of biodiversity indicators in fields of break and cereal crops changed when planted with the dedicated biomass crops, miscanthus and short rotation coppiced (SRC) willow. Weed biomass was consistently greater in the two dedicated biomass crops than in cereals, and invertebrate abundance was similarly consistently higher than in break crops. Using canonical variates analysis, we identified distinct plant and invertebrate taxa and trait‐based communities in miscanthus and SRC willows, whereas break and cereal crops tended to form a single, composite community. Seedbanks were shown to reflect the longer term effects of crop management. Our study suggests that miscanthus and SRC willows, and the management associated with perennial cropping, would support significant amounts of biodiversity when compared with annual arable crops. We recommend the strategic planting of these perennial, dedicated biomass crops in arable farmland to increase landscape heterogeneity and enhance ecosystem function, and simultaneously work towards striking a balance between energy and food security.     

Canonical correlation analysis of marine macrobenthos survey data

Canonical correlation analysis is applied to measurements of environmental variables and species distributions made during a survey of macrobenthos around a sewage-treatment farm drain. The implications of data reduction, necessary to enable the method to proceed, are discussed. The amount of data was reduced by discarding the rarest species, discarding species occurring at fewest stations, and including only those species and environmental variables which correlated highly with the greatest number of other variables. Only the third data-reduction scheme gave ecologically sensible results. Use of station scores on the first two canonical variates (CV1 and CV2) enabled the sampling grid to be divided into a group of nearshore stations, a group of intermediate depth, and a group of deep offshore stations. Loadings of environmental variables on the canonical variates were found to be unstable but correlations between these variables and canonical variates enabled the variates to be interpreted: CV1 as a gradient of depth and associated changes in sediment characteristics, CV2 with depth- and nutrient-related components, and CV3 as patchiness in sediment characteristics different from that normally expected with depth. Use of correlations between species and canonical variates enables definition of two major species groups, one confined to nearshore environments and a second offshore. These groups (and their sub-groups) related well to groups defined previously by hierarchical classification. It is concluded that, with careful attention to the method of data reduction, canonical correlation analysis can be an effective tool in the analysis of marine benthic survey data.     

Patterns of morphological discrimination in selected human tarsal elements

A suite of measurements was collected from the talus, calcaneus, navicular, and cuboid of humans from Southern China, Victorian Britain, Roman Britain, and Zulu tribes people from the Republic of South Africa. Univariate and multivariate statistical analyses of dimensions of individual foot bones revealed subtle but distinct patterns of morphological discrimination on the basis of sex and size on the one hand, and geographical relationships on the other. These differences are largely expressed in the first three canonical variates of the multivariate analyses: the first axis expresses both sex and size differences, and the second and third, geographical group differences. Confirmation of morphological patterns obtained from individual multivariate analyses was provided by an integrated analysis of the four tarsal elements together. However, the integrated analysis also gave larger separations with discriminations along different axes. Thus the three geographical groups (Zulus, Southern Chinese, and the two British groups together) were separated by first and third variates. The discrimination of sex and size differences was found in the second axis, mirroring what was found in the first axes of the individual studies. This axis reversal implies that in examining all bones together, there is enough redundant information about sex and size in each individual bone that they are relegated to a second axis. It likewise implies that the data referring to geographic discriminations provided by each individual bone are not redundant; they sum in the integrated analysis, and therefore contribute to the overall analysis to a greater extent, with increased clarity.     

Within- and among-lake variation in shell morphology of the freshwater clam Elliptio complanata (Bivalvia: Unionidae) from south-central Ontario lakes

To compare the relative magnitude of variation in shell morphology within and among lakes, Elliptio complanata were collected from low and high exposure areas in each of four small lakes in south-central Ontario. Nested ANOVA's on shell length, height, width and weight revealed that shell morphology varied much more between sites of differing exposure within a lake than among lakes of differing alkalinity. Canonical variates analysis showed that clams from high exposure areas had larger and proportionately taller and heavier shells than those from low exposure areas. There was no relationship between alkalinity of lakes and shell morphology. These results suggest that the use of unionid shell morphology to predict long-term whole lake water chemistry (e.g. alkalinity) requires sampling designs which take into account within-lake variation in shell morphology.     

A craniometric study of the black and white Colobus Illiger 1811 (Primates: Ceropithecoidea).

This study examines the craniometry of Black and White Colobus monkeys using 1072 specimens representing all the recognized subspecies (after Rahm, '70) of the genus. Seventy-six measurements were taken on each individual, and examined using canonical variates analysis and clustering by Ward's Error Sum method. The assumptions of the analytical techniques are shown to be met, and the results demonstrated to be stable. Examination of the populations for statistical difference and taxonomic distinctiveness using a multivariate extension of Mayr's Rule indicates that the taxonomy presented by Rahm ('70) is essentially correct, except that the subspecies of guereza across the northern part of Central Africa should be lumped into a single group--C. g. occidentalis--and the subspecies of montane angolan colobus in Eastern Zaire should all be lumped into C. a. ruwenzorii. The systematic patterns of the genus illustrate the whole range of the process of speciation, from barely distinct subspecies, to subspecies almost as distinct as allopatric species of the genus, and on the fully sympatric species Three major zoogeographic areas may be delineated: an East African area dominated by the effects of the Rift Valley, with a large number of subspecies isolated in forest islands; a Central African area with little subspeciation and sympatric overlap of the major species of Colobus; and a West African area with a clinal pattern of distribution of subspecies, and secondary intergradation. The arbitrary nature of Mary's Rule is also apparent. Lastly, the CVA indicated major differences across the genus to be located in the teeth and jaws, suggesting diet might be an important distinguishing feature in Colobus.     

典范分析法在黄河三角洲菜州湾滨海区盐生植物群落研究中的应用

 典范变量分析能同时处理两种类型的变量集并给出它们之间的相关系数。本文采用该方法对黄河三角洲地区的10个植物群丛及其土壤的有关性质进行了分析。典范相关系数是0.9和1。文中同时求出了所有典范变量,保留了原数据的全部信息。结果表明该地区植被的动态变化与土壤水盐及有机质含量的动态变化显著相关。土壤的水盐动态是这一地区植被演替的制约因素。二维典范变量图较直观地表示出了群丛间的演替关系。初步判断出芦苇和白茅群丛是这一地区植被演替过程中相对稳定的阶段。该方法对研究植物群落的分布及植被演替等内容是很有帮助的。     

Morphological analysis of three equivocal sibling species of Deprea (Solanaceae)

Taxonomic confusion among closely related and morphologically similar Deprea species has persisted in the literature and in the identification of species. Morphological variation among three closely related, monophyletic Deprea species was studied to determine if and how they can be distinguished. Their sympatric occurrence in Venezuela afforded an opportunity to couple field study with analysis of herbarium specimens representing their entire geographic range. An analysis of 94 morphological characters resulted in five vegetative and 13 reproductive taxonomically informative traits. Canonical variates analysis clearly separated the three species using six quantitative traits. We conclude that these taxa, although quite variable and similar morphologically, are taxonomically distinct. Results of character analysis indicated that D. orinocensis is morphologically more similar to D. bitteriana than either are to D. paneroi. In D. paneroi, small, sterile anthers on fruit-bearing plants and the absence of fruits on plants possessing large, plllen-bearing anthers, suggest cryptic dioecy. Based on these data, D. granulosa is considered to be a synonym of D. orinocensis: Athenaea bitteriana, a misapplied synonym, is the correct basionym and is applicable to many specimens identified as D. granulosa. We submit a new combination, D. bitteriana (Werderm.) Sawyer & Benítez, and designate a lectotype to accommodate these findings.     

典范分析法在黄河三角洲莱州湾滨海区盐生植物群落研究中的应用

典范变量分析能同时处理两种类型的变量集并给出它们之间的相关系数。本文采用该方法对黄河三角洲地区的10个植物群丛及其土壤的有关性质进行了分析。典范相关系数是0.9和1。文中同时求出了所有典范变量,保留了原数据的全部信息。结果表明该地区植被的动态变化与土壤水盐及有机质含量的动态变化显著相关。土壤的水盐动态是这一地区植被演替的制约因素。二维典范变量图较直观地表示出了群丛间的演替关系。初步判断出芦苇和白茅群丛是这一地区植被演替过程中相对稳定的阶段。该方法对研究植物群落的分布及植被演替等内容是很有帮助的。     

The Calcaneum—On the Heels of Marsupial Locomotion

The potential for making functional interpretations from a single postcranial element for marsupials was investigated through morphometric analysis of the calcanea of 61 extant species from Australia and New Guinea. Extant species were grouped into locomotor categories and a canonical variates analysis was carried out on measurements of their calcanea. A relationship between measurements of the calcanea and the locomotor behavior of species was found, allowing for prediction of locomotor behavior from calcaneum morphometrics. This was applied to fossil marsupial taxa, from early–late Miocene/?Pliocene deposits at Riversleigh, in an attempt to determine their locomotor behavior. Hopping (saltatorial) taxa are distinguished from quadruped terrestrial taxa and taxa capable of climbing (arboreal and scansorial) by their relatively longer tuber calcis and wider calcaneal head, by their dorso-ventrally thicker calcaneal head, and by their calcaneocuboid facet being less steeply angled antero-posteriorly. Taxa capable of climbing are distinguished from quadruped terrestrial taxa by their shorter tuber calcis relative to the calcaneal head and by their smaller calcaneo-astragalar facet. The locomotor categories distinguished in this study (arboreal/scansorial, quadruped terrestrial, and saltatorial) highlight differences between species in their use of available substrates and thus are informative with regards to the structural components of their habitat. The results of this analysis can be used, in combination with other data, to make inferences about the habitats of paleocommunities at Riversleigh through the Miocene. The calcaneum is a dense and very robust element and, therefore, has a good chance of being preserved. This method provides a quick and easy way of inferring locomotion and has a wide potential for application to many fossil deposits because it requires only a single element.