Canonical Variate Analysis Research Articles

Variation Morphologique Adaptative Des Populations De Sarotherodon Melanotheron Des Secteurs IV Et V De La Lagune Ebrié (Côte d’Ivoire) Face Au Stress Chimique

The impact of chemical pollution on organism’s characteristics was assessed through morphological features in IV and V sectors of Ebrié Lagoon using Sarotherodon melanotheron (Rüppel, 1852) as bioindicator. Sampling was carried out during a whole year in three sites (Layo, N’djem and Ahua) characterized by contrasted environments(respectively moderate, medium and high levels of pollution). The morphological studies were based on morphometric biomarkers such as fluctuating asymmetry (FA) and average body shape. Fluctuating asymmetry was evaluated among individuals within sites using ANOVA Procrustes. Average body shape was compared among sampling sites using Principal Components Analysis (PCA), Canonical Variates Analysis (CVA) and MANOVA. Fluctuating asymmetry did not vary between sampling sites. However, the average body shape was significantly different between specimens from Ahua and both those from Layo and N’djem. There was no significant difference between fish from Layo and those from N’djem.Allometric effects and the abiotic parameters influenced, to some extent, the body shape of individuals.A morphological differentiation according to the geographical distance was also observed. The study revealed a morphological adaptation of the populations of S. melanotheron in the study area.

Effects of the Y-chromosome and the dominant hemimelia mutation on the morphology of the mouse mandible.

The aims of this study were to test whether the Y-chromosome and the autosomal dominant hemimelia (Dh) mutation can affect mandible morphology in mice. I analyzed mandible size and shape using landmark-based geometric morphometrics in 16 DH-Chr Y@ -+/+ (@ represents one of the inbred strain names) strains and observed significant differences in mandible size. The largest mandible was identified in strain DH-Chr YC3H and the smallest in strain DH-Chr YKK . Canonical variate and discriminant function analyses suggested that the mandible shapes of strains DH-Chr YC3H and DH-Chr YKK differed from those of the other strains. Because seven of the DH-Chr Y@ -+/+ strains were maintained with dominant hemimelia, I also analyzed the potential influence of dominant hemimelia on mandible morphology because dominant hemimelia is known to cause various skeletal malformations. There were no significant differences in mandible size in seven sets of DH-Chr Y@ -+/+ and DH-Chr Y@ -Dh/+ strains. However, canonical variate analysis mapped strains DH-Chr YCAS -Dh/+ and DH-Chr YCBA -Dh/+ mapped distantly from the rest. Additionally, I observed similar patterns of shape change between DH-Chr YCAS -+/+ and DH-Chr YCAS -Dh/+, and between DH-Chr YCBA -+/+ and DH-Chr YCBA -Dh/+. These data indicate that the Y-chromosome affects the size and shape of the mouse mandible. Dominant hemimelia affects mandible shape but not size, and its effects emerge depending on the kinds of Y-chromosomes.

S62. Computational diagnosis of ion channel dysfunction in NMDA receptor antibody encephalitis

Introduction NMDA receptor (NMDAR) antibody encephalitis is an autoimmune disorder causing acute psychosis, confusion and seizures. Electroencephalography (EEG) findings are usually non-specific, with diagnosis confirmed by demonstration of serum/CSF autoantibodies. Improved clinical outcomes depend on early institution of immunotherapies. A non-invasive measure of NMDAR function could facilitate early treatment, and enable tracking of disease activity. Recent biophysical modeling advances allow inference of ion channel dynamics from macroscopic measures of brain activity. Here, we show that clinically relevant diagnoses of NMDAR ion channel dysfunction can be obtained using a microcircuit model fitted to individual human EEG data. Methods We compared resting state EEG cross-spectra from patients with NMDAR encephalitis, encephalopathy unrelated to NMDAR dysfunction, and non-encephalopathic controls. We fit biophysical models (dynamic causal models – DCMs) of connected neuronal ensembles, simulating post-synaptic membrane potentials and EEG spectra through lead field projection. We used canonical variate analysis (CVA) and an empirical Bayesian approach searching candidate models across the groups to reveal specific synaptic deficits. Results Clinical severity was matched between encephalopathic groups. However, there were clear differences in EEG cross-spectra at low (2–4 Hz) and high (28–40 Hz) frequencies, with increased beta-gamma power present in NMDAR antibody encephalitis patients. Subject-specific DCMs mapped model parameters representing dynamics at NMDA, AMPA and GABA receptors to spectral data features. Four inter-connected sources described delta-theta and beta-gamma cross-spectra observed at scalp sensors. Each source comprised a neural mass model with four neuronal subpopulations, with dynamics determined by intrinsic connections mediated via ionotropic receptors. Dynamics along intrinsic and extrinsic connections could reproduce scalp-based EEG recordings. Parameter estimate CVA showed significant differences between patients with and without NMDAR encephalitis in NMDAR parameters. A parametric empirical Bayes (PEB) analysis demonstrated that the group effects of NMDAR encephalitis were specific to NMDA model parameters, in contrast to other encephalopathies where differences were seen across receptor subtypes. Conclusion Neurological and psychiatric practice lack diagnostic probes to assess disease mechanisms at the neuronal level non-invasively in humans. We show that biophysical models of EEG applied to clinical EEG data identify abnormal NMDAR signaling in patients with NMDAR encephalitis but not in patients with other encephalopathies or neurological controls. By comparing model parameter estimates from these patient groups, we selectively identify NMDAR dysfunction in a multi ion-channel model. Given that EEG is ubiquitously available, our findings suggest the feasibility of EEG neuromodeling as a unique assay of brain dysfunction at the molecular-level.

Patterns of lateral enamel growth in Homo naledi as assessed through perikymata distribution and number

Perikymata, incremental growth lines visible on tooth enamel surfaces, differ in their distribution and number among hominin species, although with overlapping patterns. This study asks: (1) How does the distribution of perikymata along the lateral enamel surface of Homo naledi anterior teeth compare to that of other hominins? (2) When both perikymata distribution and number are analyzed together, how distinct is H. naledi from other hominins? A total of 19 permanent anterior teeth (incisors and canines) of H. naledi were compared, by tooth type, to permanent anterior teeth of other hominins: Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, Paranthropus boisei, Homo ergaster/Homo erectus, other early Homo, Neandertals, and modern humans, with varying sample sizes. Repeated measures analyses of the percentage of perikymata per decile of reconstructed crown height yielded several statistically significant differences between H. naledi and other hominins. Canonical variates analysis of percentage of perikymata in the cervical half of the crown together with perikymata number revealed that, in 8 of 19 cases, H. naledi teeth were significantly unlikely to be classified as other hominins, while exhibiting least difference from modern humans (especially southern Africans). In a cross-validated analysis, 68% of the H. naledi teeth were classified as such, while 32% were classified as modern human (most often southern African). Of 313 comparative teeth use for this analysis, only 1.9% were classified as H. naledi. What tends to differentiate H. naledi anterior tooth crowns from those of most other hominins, including some modern humans, is strongly skewed perikymata distributions combined with perikymata numbers that fall in the middle to lower ranges of hominin values. H. naledi therefore tends toward a particular combination of these features that is less often seen in other hominins. Implications of these data for the growth and development of H. naledi anterior teeth are considered.

Taxonomic assessment of Australian Eocyzicus species (Crustacea: Branchiopoda: Spinicaudata).

Herein we describe nine species of Eocyzicus from Australia and re-describe the morphological variability of Eocyzicus parooensis Richter Timms, 2005 and Eocyzicus argillaquus Timms Richter, 2009. All species were previously delimited by molecular phylogenetic analyses and the species descriptions are based on the same individuals. Characters were scored with the aid of the taxonomic software DELTA. The morphological analyses largely corroborated the previously delimited species despite high levels of intraspecific variability that overlapped with interspecific variation in many instances. Morphological species delimitation was generally supported by principal component and canonical variate analyses. Characters best suited for morphological species identification were the numbers of growth lines on the carapace, the number of telsonic spines and the number of setae on the furca.

Tegmina-size variation in a Neotropical cricket with implications on spectral song properties

This study evaluates the relationship between shape and size of tegmen, harp, mirror, and spectral range of calling song frequency of a Neotropical cricket subpopulation (Lerneca inalata beripocone. In addition, we compare intraspecific morphological divergence and calling song properties between individuals from different sites of the Pantanal of Poconé, Mato Grosso, Brazil. Regression analysis showed that the dominant and maximum calling song frequencies were negatively correlated with tegmen size, i.e. frequencies are either lower or higher depending on the corresponding size variation in resonance structures of the forewings. Canonical variable analysis demonstrated marked intraspecific differences in morphometric characters between localities of a L. inalata subpopulation c. 35 km apart (SESC-Pantanal Advanced Research Base and Pouso Alegre Farm, Mato Grosso, Brazil). Lerneca inalata beripocone at SESC had larger forewings than conspecifics from Pouso Alegre Farm. These morphological variations of wing properties related to reproductive behaviours were interpreted as fitness parameters, likely shaped by restricted gene flow during temporal habitat isolation episodes. Such isolation patterns occur in the Pantanal wetlands for several months during the annual hydrological cycle.

Re-defining burrowing crayfish in a new way using morphometrics.

All crayfish worldwide can be defined as one of the three types of burrower. However, burrowing types were created using behavior and habitat. Geometric morphometrics via landmarks can be used to determine similarities and differences between burrowing types. It is hypothesized that multiple genera that fall under one type of burrower will have a closer correlation to each other in terms of body shape. The findings could possibly be used as another parameter in the determination of a burrowing type but may also give some insight into the evolution of crayfishes.In this study, eight species were chosen from the West Liberty University Crayfish Conservation Lab collection. There were two tertiary burrowing species, and three secondary burrowing species, and one unknown burrowing species chosen. Of the tertiary, secondary, and unknown burrowing species, 30 specimens were chosen of each. Ten form-I males, ten form-II males, and ten females served as representatives of each species. Two primary burrowing species were also chosen. Representing these species were five form-I males, five form-II males, and five females. Every individual crayfish had a photograph taken of the cephalothorax and was catalogued. Images were then used to create a .tps file to be landmarked in the program TPSDig 232. Fifteen landmarks were chosen across the cephalothorax. The data was then analyzed using a principal component analysis and a canonical variate analysis.

Sexual Dimorphism of the Zygomatic Bone

This study assessed the posterior contour of left- and right-sided zygomatic bones, hypothesizing that female and male crania would exhibit different contours. The study analyzed lateral cranial views of 252 female and 318 zygomatic bones. The distance from the zygomaticofrontal suture to the jugale was calculated in addition to the length of the posterior border of the frontal process of the zygomatic bone to determine the degree of deviation from a straight line. The contour length between males and females did not differ (t=1.577(593); p=0.12) nor did the degree of deviation from a straight line (t=1.808(593); p=0.07). However, there were significant differences with regard to side (t=5.589(614); p<0.0001 and t=3.742(614); p=0.0002). Discriminant function analysis revealed no significant shape difference between sides or sexes (T2=338.7; p=0.15 and T2=244.3; p=0.94, respectively). However, canonical variate analysis demonstrated statistically significant shape differences among sexes with regard to side. The results of this study reveal morphological variation in the zygomatic bone that may differentiate sex.

Maternal environment and craniofacial growth: geometric morphometric analysis of mandibular shape changes with in utero thyroxine overexposure in mice.

An estimated 3% of US pregnancies are affected by maternal thyroid dysfunction, with between one and three of every 1000 pregnancies being complicated by overactive maternal thyroid levels. Excess thyroid hormones are linked to neurological impairment and excessive craniofacial variation, affecting both endochondral and intramembranous bone. Using a geometric morphometric approach, this study evaluates the role of in utero thyroxine overexposure on the growth of offspring mandibles in a sample of 241 mice. Canonical variate analysis utilized 16 unilateral mandibular landmarks obtained from 3D micro-computed tomography to assess shape changes between unexposed controls (n = 63) and exposed mice (n = 178). By evaluating shape changes in the mandible among three age groups (15, 20 and 25 days postnatal) and different dosage levels (low, medium and high), this study found that excess maternal thyroxine alters offspring mandibular shape in both age- and dosage-dependent manners. Group differences in overall shape were significant (P < 0.001), and showed major changes in regions of the mandible associated with muscle attachment (coronoid process, gonial angle) and regions of growth largely governed by articulation with the cranial base (condyle) and occlusion (alveolus). These results compliment recent studies demonstrating that maternal thyroxine levels can alter thecranial base and cranial vault of offspring, contributing to a better understanding of both normal and abnormal mandibular development, as well as the medical implications of craniofacial growth and development.

Divergence in nutrient concentration, in vitro degradation and gas production potential of spineless cactus genotypes selected for insect resistance

AbstractForage cactus is an important dry-season feed source for livestock in semi-arid regions, but in north-eastern Brazil, its contribution is limited by susceptibility to the carmine cochineal [Dactylopius opuntiae (Cockerell)] insect. New cactus germplasm shows superior agronomic performance, but the nutritive value of this material has not been adequately described. The objective of the current study was to assess the divergence in chemical composition and rate and extent of in vitro degradation of these genotypes. The treatments were 13 spineless cactus genotypes, eight of which were insect resistant types, two semi-resistant and three susceptible to the carmine cochineal. Treatments were arranged in a randomized complete block design and were replicated three times. Nutritional divergence was assessed using canonical variate analysis and hierarchical agglomerative clustering, using the variables: crude protein, total and non-fibrous carbohydrates, degradation rate and potential dry matter degradation. Five distinct nutritional groups were identified: Group I (OO), Group II (F-13 and F-15), Group III (OEA, OEM, COP, IPA 20 and GG), Group IV (V-16 and F-08) and Group V (Miuda, IS and F-21). Group II (F-13 and F-15; resistant genotypes) showed a chemical composition degradability in vitro suggesting it may have the greatest nutritive value as ruminant feed, while Group I had the least. Spineless cactus genotypes resistant to the carmine cochineal showed nutritional characteristics similar to or better than traditionally used cactus genotypes, such as Gigante and IPA 20, which can expand the range of options for using this forage.

Morphological Variation in the Posterior Margin of the Frontal Process of the Zygomatic Bone

Based on the observation that some crania exhibit a pronounced marginal tubercle, whereas others do not, this study assessed the contour of the zygomatic bone hypothesizing that female and male crania would exhibit different contours. The study included 616 norma lateralis images of a mixed sample of female (n=252) and male (n=318) cranial sides. Images from crania of questionable sex and were excluded from analysis between sexes. The linear distance from the zygomaticofrontal suture to the jugale was calculated in addition to the length of the posterior border of the frontal process of the zygomatic bone to determine the degree of deviation from a straight line. The contour length between males and females did not differ (t=1.577(593); p=0.12) nor did the degree of deviation from a straight line (t=1.808(593); p=0.07). Independent of sex, however, there were significant differences in the aforementioned parameters with regard to side (t=5.589(614); p&lt;0.0001 and t=3.742(614); p=0.0002, respectively). Procrustes superimposition demonstrated the average contour which can be given as y≈44.074x4 + 0.7995x3 −2.6286x2 −0.0122x + 0.0182. Principle component analysis explained 74.6% of shape variation with the first two principle components (PC1=48.8%; PC2=25.8%). With regard to differences in the shape of the contour between sides or sexes, discriminant function analysis revealed no significant shape difference (T2=338.7; p=0.15 and T2=244.3; p=0.94, respectively). However, canonical variate analysis demonstrated statistically significant shape differences among sexes with regard to side. Female right and left sides demonstrated the most shape difference (Mahalanobis distance=2.33) whereas the least shape difference was found among right sides between males and females (Mahalanobis distance=1.83). The results of this study reveal morphological variation in the posterior margin of the frontal process of the zygomatic bone that distinguishes crania based upon sex and laterality.Support or Funding InformationWV Research Challenge Fund [HEPC.dsr.17.06] and [HEPC.dsr.14.13]This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sexual Dimorphism of the Fetal, Neonatal, and Infantile Supraorbital Rim between Races

The adult orbital rim is known to exhibit sexual dimorphism. However, the development of the orbital sexual dimorphism is poorly understood. Moreover, there has been little study of sexual dimorphism in the supraorbital rim in the early development of fontal bones. Therefore, this study assessed 188 supraorbital rims among black and white females and males of fetal, neonatal, and infantile age. The population consisted of 47 black female, 36 white female, 54 black male, and 51 white male supraorbital rims. Canonical variate analysis revealed statistically significant contour differences among all groups (p&lt;0.0001). Further, all groups separated by Mahalanobis distances greater than 11 except for black females and white males (Mahalanobis distance = 6.84). The results of this study suggest that sexual dimorphism of the supraorbital rim exists within and between races, even among fetuses.Support or Funding InformationWV Research Challenge Fund [HEPC.dsr.17.06] and [HEPC.dsr.14.13]This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Morphogeometric variation in Phrynus barbadensis (Pocock, 1893) (Amblypyghi: Phrynidae) from Colombia

Amblypygi is a small order of arachnids with features similar to spiders. In Colombia, this order has been subject to low attention, the main investigations are focused towards a taxonomic level. Recently, the geometric morphometrics has proven to be an useful tool for determining shape differences in scorpions and spiders. Due to this, we used geometric morphometrics to determine intraspecific variation in three Colombian populations of Phrynus barbadensis . We digitalized 16 anatomical points over the carapace and 15 in patella by combining landmarks and sliding semilandmarks; the coordinates were aligned by generalized Procrustes analysis. Canonical Variates Analysis was implemented with proportions of re-classified groups and MANOVA. We found significant differences of carapace conformation between populations; all specimens were 80% correctly classified. Statistical analyses of variance (ANOVA) found significant differences in carapace and patella isometric size among populations; the main carapace differences occur in anterior, posterior and right margins. The observed variation could be associated with the environmental differences between localities

Simultaneous classification of multiple classes in NMR metabolomics and vibrational spectroscopy using interval-based classification methods: iECVA vs iPLS-DA

Interval based chemometric algorithms have proven to be very powerful for spectral alignments, spectral regressions and spectral classifications. The interval-based methods may not only improve the performance, but also reduce model complexity and enhance the spectral interpretation. Extended Canonical Variate Analysis (ECVA) is a powerful method for multiple group classifications of multivariate data and can easily be extended to an interval approach, iECVA. This study outlines the iECVA method and compares its performance to interval Partial Least Squares Discriminant Analysis (iPLS-DA) on three spectroscopic datasets from Nuclear Magnetic Resonance (NMR), Near Infrared (NIR) and Infrared (IR) spectroscopy, respectively. The results invariantly show that the interval-based classification methods greatly enhance the interpretability of the models by identifying important spectral regions, which facilitate interpretation and biomarker discovery. Although the results for the two methods are similar regarding the number of misclassifications and identified important regions, the model complexity of the PLS-DA proved to consistently lower than the ECVA.The Matlab source codes for both iECVA and iPLS-DA are made freely available at www.models.life.ku.dk.

Specific-age group sex estimation of infants through geometric morphometrics analysis of pubis and ischium

Sex determination of unknown individuals is one of the primary goals of Physical and Forensic Anthropology. The adult skeleton can be sexed using both morphological and metric traits on a large number of bones. The human pelvis is often used as an important element of adult sex determination. However, studies carried out about the pelvic bone in subadult individuals present several limitations due the absence of sexually dimorphic characteristics. In this study, we analyse the sexual dimorphism of the immature pubis and ischium bones, attending to their shape (Procrustes residuals) and size (centroid size), using an identified sample of subadult individuals composed of 58 individuals for the pubis and 83 for the ischium, aged between birth and 1year of life, from the Granada osteological collection of identified infants (Granada, Spain). Geometric morphometric methods and discriminant analysis were applied to this study. The results of intra- and inter-observer error showed good and excellent agreement in the location of coordinates of landmarks and semilandmarks, respectively. Principal component analysis performed on shape and size variables showed superposition of the two sexes, suggesting a low degree of sexual dimorphism. Canonical variable analysis did not show significant changes between the male and female shapes. As a consequence, discriminant analysis with leave-one-out cross validation provided low classification accuracy. The results suggested a low degree of sexual dimorphism supported by significant sexual dimorphism in the subadult sample and poor cross-validated classification accuracy. The inclusion of centroid size as a discriminant variable does not imply a significant improvement in the results of the analysis. The similarities found between the sexes prevent consideration of pubic and ischial morphology as a sex estimator in early stages of development. The authors suggest extending this study by analysing the different trajectories of shape and size in later ontogeny between males and females.

Magnetoencephalographic Correlates of Perceptual State During Auditory Bistability

Bistability occurs when two alternative percepts can be derived from the same physical stimulus. To identify the neural correlates of specific subjective experiences we used a bistable auditory stimulus and determined whether the two perceptual states could be distinguished electrophysiologically. Fourteen participants underwent magnetoencephalography while reporting their perceptual experience while listening to a continuous bistable stream of auditory tones. Participants reported bistability with a similar overall proportion of the two alternative percepts (52% vs 48%). At the individual level, sensor space electrophysiological discrimination between the percepts was possible in 9/14 participants with canonical variate analysis (CVA) or linear support vector machine (SVM) analysis over space and time dimensions. Classification was possible in 14/14 subjects with non-linear SVM. Similar effects were noted in an unconstrained source space CVA analysis (classifying 10/14 participants), linear SVM (classifying 9/14 subjects) and non-linear SVM (classifiying 13/14 participants). Source space analysis restricted to a priori ROIs showed discrimination was possible in the right and left auditory cortex with each classification approach but in the right intraparietal sulcus this was only apparent with non-linear SVM and only in a minority of particpants. Magnetoencephalography can be used to objectively classify auditory experiences from individual subjects.

Giant ants and their shape: revealing relationships in the genus Titanomyrma with geometric morphometrics.

Shape is a natural phenomenon inherent to many different lifeforms. A modern technique to analyse shape is geometric morphometrics (GM), which offers a whole range of methods concerning the pure shape of an object. The results from these methods have provided new insights into biological problems and have become especially useful in the fields of entomology and palaeontology. Despite the conspicuous successes in other hymenopteran groups, GM analysis of wings and fossil wings of Formicidae has been neglected. Here we tested if landmarks defining the wing shape of fossil ants that belong to the genus Titanomyrma are reliable and if this technique is able to expose relationships among different groups of the largest Hymenoptera that ever lived. This study comprises 402 wings from 362 ants that were analysed and assigned with the GM methods linear discriminant function analysis, principal component analysis, canonical variate analysis, and regression. The giant ant genus Titanomyrma and the parataxon Formicium have different representatives that are all very similar but these modern methods were able to distinguish giant ant types even to the level of the sex. Thirty-five giant ant specimens from the Eckfeld Maar were significantly differentiable from a collection of Messel specimens that consisted of 187 Titanomyrma gigantea females and 42 T. gigantea males, and from 74 Titanomyrma simillima females and 21 T. simillima males. Out of the 324 Messel ants, 127 are newly assigned to a species and 223 giant ants are newly assigned to sex with GM analysis. All specimens from Messel fit to the two species. Moreover, shape affinities of these groups and the species Formicium brodiei, Formicium mirabile, and Formicium berryi, which are known only from wings, were investigated. T. gigantea stands out with a possible female relative in one of the Eckfeld specimens whereas the other groups show similar shape patterns that are possibly plesiomorphic. Formicidae are one of the most dominant taxa in the animal kingdom and new methods can aid in investigating their diversity in the present and in deep time. GM of the ant wing delivers significant results and this core of methods is able to enhance the toolset we have now to analyse the complex biology of the ants. It can prove as especially useful in the future when incorporated into better understanding aspects of evolutionary patterns and ant palaeontology.

Canonical variable analysis and long short-term memory for fault diagnosis and performance estimation of a centrifugal compressor

Centrifugal compressors are widely used for gas lift, re-injection and transport in the oil and gas industry. Critical compressors that compress flammable gases and operate at high speeds are prioritized on maintenance lists to minimize safety risks and operational downtime hazards. Identifying incipient faults and predicting fault evolution for centrifugal compressors could improve plant safety and efficiency and reduce maintenance and operation costs. This study proposes a dynamic process monitoring method based on canonical variable analysis (CVA) and long short-term memory (LSTM). CVA was used to perform fault detection and identification based on the abnormalities in the canonical state and the residual space. In addition, CVA combined with LSTM was used to estimate the behavior of a system after the occurrence of a fault using data captured from the early stages of deterioration. The approach was evaluated using process data obtained from an operational industrial centrifugal compressor. The results show that the proposed method can effectively detect process abnormalities and perform multi-step-ahead prediction of the system’s behavior after the appearance of a fault.

Evaluation of trophic parameters in newly built reservoir using canonical variates analysis

Wielkopolska region has precipitation below country average and water shortage is especially visible during spring and summer, thus regeneration of water bodies play important role in saving of water reserves in rural areas. The newly built water reservoir is located in Nienawiszcz, Rogoźno commune, Poland. The aim of study was to compare experimental sites according to parameters describing water trophy like chlorophyll a, dry mass of seston, total organic carbon, biochemical oxygen demand and according to concentrations of nitrogen and phosphorus compounds. Sites were compared using location in reservoir and year season. In the year 2014 (after connection of both parts of lake) part A and B of reservoir had similar trophic conditions, thus confirming stabilisation of the reservoir as an initial freshwater ecosystem. Water table level was also stable, thus low average water depth was not affected water quality Based on canonical variates analysis it was showed, that changes of nitrates and total nitrogen concentrations strongly affected the variability of experimental objects in comparison to concentrations of nitrites and total phosphorus. In the year 2014, after connection of both parts A and B the reservoir start to stabilise in case of similarity of water quality parameters in surveyed sites.

Research Article Genetic diversity among accessions of Capsicum annuum L. through morphoagronomic characters

Genetic variability among pepper genotypes is essential in obtaining hybrid combinations with greater heterotic effect and in obtaining superior strains. This work’s goal was to evaluate the genetic diversity between accessions of Capsicum annuum L., indicating the selection of promising individuals for ornamental purposes. The experiment was carried out in at the Plant Biotechnology Laboratory of the Center of Agricultural Sciences, Federal University of Paraiba. The experiment was conducted in a completely randomized design with 16 treatments and eight replications. The plants were evaluated for 28 morphoagronomic traits. Data were submitted to analysis of variance and grouped according to Scott and Knott's test at 1% probability. The Tocher grouping was performed based on Mahalanobis distance and analysis of canonical variables were performed with graphical dispersion of the accessions. All variables were significant by the F test (p = 0.01) and presented high heritability and a CVg/CVe ratio higher than 1.0 for most traits, indicating genetic divergence between accessions. In keeping with the Scott-Knott's test (p = 0.01), the accessions were grouped into two to eight classes, varying according to the character. The of Tocher optimization method separated the accessions into five distinct groups. There is phenotypic divergence between the accessions of Capsicum annuum L. which can be used in ornamental peppers’ breeding programs. Only the number of stamens trait presented a heritability value (65.81%) lower than 70%. The characters that most contributed to divergence among the accessions were fresh fruit mass, stem diameter, widest fruit diameter and fruit weight. The accessions UFPB001, UFPB004, UFPB45, UFPB77.3, UFPB099, UFPB134, UFPB390 and Calypso are designated as potential accessions for ideal ornamental pepper plant with vigorous seedling, small port, large flowers and small fruits. Ornamental pepper accessions with larger anthers are indicated for selection, for facilitating the breeder’s work during flower emasculations for crossings.