980 resultados para Morphological study


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Dioon Lindl. (Zamiaceae) is a small genus restricted to Mexico (12 species) and Honduras (one species). Previous systematic studies have been unable to fully resolve species relationships within the genus. Phylogenetic analyses were conducted with data from several sources, including Restriction Fragment Length Polymorphisms from the chloroplast genome, morphology, two introns of the low copy nuclear gene S-adenosyl-L-homocysteine hydrolase (SAHH) and the 5.8S/ITS2 regions of the nuclear ribosomal DNA. The goals of the study were to construct a total evidence species level phylogeny and to explore current biogeographical hypotheses. None of the analyses performed produced a fully resolved topology. Dioon is comprised of two main lineages (the Edule and Spinulosum Clades), which represents an ancient divergence within the genus. The two introns of the nuclear gene SAHH offer additional evidence for the split into two lineages. Intron 2 contains a 18 bp deletion in the Spinulosum Clade, providing a synapomorphy for that group. The 5.8S/ITS2 regions were highly polymorphic and subsequently omitted from the combined analyses. In order to visualize congruence between morphology and molecular data, morphological characters were mapped onto the combined molecular tree. Current biogeographical hypotheses of a general northward pattern of migration and speciation are supported here. However, sister relationships within the Edule Clade are not fully resolved. Seven DNA microsatellite markers were developed to investigate patterns of genetic variation of seven populations of D. edule, a species restricted to Eastern Mexico. We found that most of the genetic variation lies within populations (Ho = 0.2166–0.3657) and that levels of population differentiation are low (Fst = 0.088); this finding is congruent with the breeding system of this species, dioicy. Four of the populations deviate from Hardy Weinberg Equilibrium and have a high number of identical genotypes, we suggest that this unexpected pattern is due to the life-history strategy of the species coupled with the few number of polymorphic loci detected in these populations. Our results are not congruent with earlier evidence from morphology and allozyme markers that suggest that the two northernmost populations represent a distinct entity that is recognized by some taxonomists as D. angustifolium.

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• Premise of the study: Species in the aquatic genus Nymphoides have inflorescences that appear to arise from the petioles of floating leaves. The inflorescence-floating leaf complex can produce vegetative propagules and/or additional inflorescences and leaves. We analyzed the morphology of N. aquatica to determine how this complex relates to whole plant architecture and whether whole plant growth is sympodial or monopodial. • Methods: We used dissections, measurements, and microscopic observations of field-collected plants and plants cultivated for 2 years in outdoor tanks in south Florida, USA. • Key results: Nymphoides aquatica had a submerged plagiotropic rhizome that produced floating leaves in an alternate/spiral phyllotaxy. Rhizomes were composed of successive sympodial units that varied in the number of leaves produced before the apex terminated. The basic sympodial unit had a prophyll that subtended a renewal-shoot bud, a short-petioled leaf (SPL) with floating lamina, and an inflorescence; the SPL axillary bud expanded as a vegetative propagule. Plants produced either successive basic sympodial units or expanded sympodia that intercalated long-petioled leaves between the prophyll and the SPL. • Conclusions: Nymphoides aquatica grows sympodially, forming a rhizome composed of successive basic sympodia and expanded sympodial units. Variations on these types of sympodial growth help explain the branching patterns and leaf morphologies described for other Nymphoides species. Monitoring how these two sympodial phases are affected by water depth provides an ecologically meaningful way to assess N. aquatica’s responses to altered hydrology.

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Airborne Light Detection and Ranging (LIDAR) technology has become the primary method to derive high-resolution Digital Terrain Models (DTMs), which are essential for studying Earth's surface processes, such as flooding and landslides. The critical step in generating a DTM is to separate ground and non-ground measurements in a voluminous point LIDAR dataset, using a filter, because the DTM is created by interpolating ground points. As one of widely used filtering methods, the progressive morphological (PM) filter has the advantages of classifying the LIDAR data at the point level, a linear computational complexity, and preserving the geometric shapes of terrain features. The filter works well in an urban setting with a gentle slope and a mixture of vegetation and buildings. However, the PM filter often removes ground measurements incorrectly at the topographic high area, along with large sizes of non-ground objects, because it uses a constant threshold slope, resulting in "cut-off" errors. A novel cluster analysis method was developed in this study and incorporated into the PM filter to prevent the removal of the ground measurements at topographic highs. Furthermore, to obtain the optimal filtering results for an area with undulating terrain, a trend analysis method was developed to adaptively estimate the slope-related thresholds of the PM filter based on changes of topographic slopes and the characteristics of non-terrain objects. The comparison of the PM and generalized adaptive PM (GAPM) filters for selected study areas indicates that the GAPM filter preserves the most "cut-off" points removed incorrectly by the PM filter. The application of the GAPM filter to seven ISPRS benchmark datasets shows that the GAPM filter reduces the filtering error by 20% on average, compared with the method used by the popular commercial software TerraScan. The combination of the cluster method, adaptive trend analysis, and the PM filter allows users without much experience in processing LIDAR data to effectively and efficiently identify ground measurements for the complex terrains in a large LIDAR data set. The GAPM filter is highly automatic and requires little human input. Therefore, it can significantly reduce the effort of manually processing voluminous LIDAR measurements.

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Scientific reading research has produced substantial evidence linking specific reading components to a range of constructs including phonological awareness (PA), morphological awareness, orthographic processing (OP), rapid automatized naming, working memory and vocabulary. There is a paucity of research on Arabic, although 420 million people around the world (Gordon, 2005) speak Arabic. As a Semitic language, Arabic differs in many ways from Indo-European languages. Over the past three decades, literacy research has begun to elucidate the importance of morphological awareness (MA) in reading. Morphology is a salient aspect of Arabic word structure. This study was designed to (a) examine the dimensions underlying MA in Arabic; (b) determine how well MA predicts reading; (c) investigate the role of the standard predictors in different reading outcomes; and (d) investigate the construct of reading in Arabic. This study was undertaken in two phases. In Phase I, 10 MA measures and two reading measures were developed, and tested in a sample of 102 Grade 3 Arabic-speaking children. Factor analysis of the 10 MA tasks yielded one predominant factor supporting the construct validity of MA in Arabic. Hierarchical regression analyses, controlling for age and gender, indicated that the MA factor solution accounted for 41– 43% of the variance in reading. In Phase II, the widely studied predictor measures were developed for PA and OP in addition to one additional measure of MA (root awareness), and three reading measures In Phase II, all measures were administered to another sample of 201 Grade 3 Arabic-speaking children. The construct of reading in Arabic was examined using factor analysis. The joint and unique effects of all standard predictors were examined using different sets of hierarchical regression analyses. Results of Phase II showed that: (a) all five reading measures loaded on one factor; (b) MA consistently accounted for unique variance in reading, particularly in comprehension, above and beyond the standard predictors; and (c) the standard predictors had differential contributions. These findings underscore the contribution of MA to all components of Arabic reading. The need for more emphasis on including morphology in Arabic reading instruction and assessment is discussed.

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Over the years, many reviews of different aspects of diatom biology, ecology and evolution have appeared. Since 1993 many molecular trees have been produced to infer diatom phylogeny. In 2004, Medlin & Kaczmarska revised the systematics of the diatoms based on more than 20 years of consistent recovery of two major clades of diatoms that did not correspond to a traditional concept of centrics and pennates and established three classes of diatoms: Clade 1 = Coscinodiscophyceae (radial centrics) and Clade 2 = Mediophyceae (polar centrics + radial Thalassiosirales) and Bacillariophyceae (pennates). However, under certain analytical conditions, an alternative view of diatom evolution, a grades of clades, has been recovered that suggests a gradual evolution from centric to pennate symmetry. These two schemes of diatom evolution are evaluated in terms of whether or not the criteria advocated by Medlin & Kaczmarska that should be met to recover monophyletic classes have been used. The monophyly of the three diatom classes can only be achieved if (1) a secondary structure of the small subunit (SSU) rRNA gene was used to construct the alignment and not an alignment based on primary structure and (2) multiple outgroups were used. These requirements have not been met in each study of diatom evolution; hence, the grade of clades, which is useful in reconstructing the sequence of evolution, is not useful for accepting the new classification of the diatoms. Evidence for how these two factors affect the recovery of the three monophyletic classes is reviewed here. The three classes have been defined by clear morphological differences primarily based on gametangia and auxospore ontogeny and envelope structure, the presence or absence of a structure (tube process or sternum) associated with the annulus and the location of the cribrum in those genera with loculate areolae. New evidence supporting the three clades is reviewed. Other features of the cell are examined to determine whether they can also be used to support the monophyly of the three classes.

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Over the years, many reviews of different aspects of diatom biology, ecology and evolution have appeared. Since 1993 many molecular trees have been produced to infer diatom phylogeny. In 2004, Medlin & Kaczmarska revised the systematics of the diatoms based on more than 20 years of consistent recovery of two major clades of diatoms that did not correspond to a traditional concept of centrics and pennates and established three classes of diatoms: Clade 1 = Coscinodiscophyceae (radial centrics) and Clade 2 = Mediophyceae (polar centrics + radial Thalassiosirales) and Bacillariophyceae (pennates). However, under certain analytical conditions, an alternative view of diatom evolution, a grades of clades, has been recovered that suggests a gradual evolution from centric to pennate symmetry. These two schemes of diatom evolution are evaluated in terms of whether or not the criteria advocated by Medlin & Kaczmarska that should be met to recover monophyletic classes have been used. The monophyly of the three diatom classes can only be achieved if (1) a secondary structure of the small subunit (SSU) rRNA gene was used to construct the alignment and not an alignment based on primary structure and (2) multiple outgroups were used. These requirements have not been met in each study of diatom evolution; hence, the grade of clades, which is useful in reconstructing the sequence of evolution, is not useful for accepting the new classification of the diatoms. Evidence for how these two factors affect the recovery of the three monophyletic classes is reviewed here. The three classes have been defined by clear morphological differences primarily based on gametangia and auxospore ontogeny and envelope structure, the presence or absence of a structure (tube process or sternum) associated with the annulus and the location of the cribrum in those genera with loculate areolae. New evidence supporting the three clades is reviewed. Other features of the cell are examined to determine whether they can also be used to support the monophyly of the three classes.

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[EN] The taxonomy of pedunculate cirripedes belonging to the genus Pollicipes has essentially remained unchanged since Charles Darwin described them in his exhaustive work on the Cirripedia. This genus includes three species of stalked barnacles: Pollicipes pollicipes in the north-eastern Atlantic, P. polymerus in the north-eastern Pacific and P. elegans in the central-eastern Pacific. However, a population genetics analysis of P. pollicipes suggested the presence of a putative cryptic species collected from the Cape Verde Islands in the central-eastern Atlantic. This study examines the morphology of these genetically divergent specimens and compares them with that of representative Atlantic samples of the biogeographically closely related P. pollicipes and with the poorly described P. elegans.

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PURPOSE: To assess and describe sequential morphological changes in the choroidal neovascularization (CNV) net using optical coherence tomography angiography (OCTA) in patients undergoing treatment with intravitreal antivascular endothelial growth factor (VEGF). METHODS: Prospective cohort study. OCTA was performed sequentially: before (t0), 1 h (t1), 1 week (t2) and 1 month after the injection (t3), using Avanti RTVue XR equipped with the AngioVue® software (Optovue, Calif., USA). All images were classified by two independent graders. RESULTS: Ten eyes of 10 patients, with a mean age of 72.4 ± 10.5 years, were included. CNV morphology was described as tree-like in 5 eyes, glomerular in 1 and fragmented in 4. A fibrovascular capsule surrounding the CNV net was found in 4 eyes and a feeder trunk was noticed in 6. No changes were observed at t1. Loss of peripheral capillaries, vessel fragmentation and decreased vessel density were evident in 8 eyes at t2. The CNV capillary density and the peripheral anastomosis increased in all of these at t3. Two eyes remained unchanged through the whole length of follow-up. CONCLUSIONS: Significant changes in the CNV net can be observable in OCTA at least 1 week after intravitreal anti-VEGF. The safety of frequent examinations may provide a method of gauging treatment effects.

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PURPOSE: To assess and describe sequential morphological changes in the choroidal neovascularization (CNV) net using optical coherence tomography angiography (OCTA) in patients undergoing treatment with intravitreal antivascular endothelial growth factor (VEGF). METHODS: Prospective cohort study. OCTA was performed sequentially: before (t0), 1 h (t1), 1 week (t2) and 1 month after the injection (t3), using Avanti RTVue XR equipped with the AngioVue® software (Optovue, Calif., USA). All images were classified by two independent graders. RESULTS: Ten eyes of 10 patients, with a mean age of 72.4 ± 10.5 years, were included. CNV morphology was described as tree-like in 5 eyes, glomerular in 1 and fragmented in 4. A fibrovascular capsule surrounding the CNV net was found in 4 eyes and a feeder trunk was noticed in 6. No changes were observed at t1. Loss of peripheral capillaries, vessel fragmentation and decreased vessel density were evident in 8 eyes at t2. The CNV capillary density and the peripheral anastomosis increased in all of these at t3. Two eyes remained unchanged through the whole length of follow-up. CONCLUSIONS: Significant changes in the CNV net can be observable in OCTA at least 1 week after intravitreal anti-VEGF. The safety of frequent examinations may provide a method of gauging treatment effects.

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Research clearly shows that physical activity (PA) is an important factor to develop and maintain good health and adequate body functions in older people. In this context, the purpose of this study was to determine aerobic performance and morphological modifications after a 4 month physical activity program (PAP) in elderly. METHODS Forty subjects divided in two groups (control, n=20; and experimental, n=20) were evaluated twice, at the beginning and after a 4-month-activity program period. This program called “+ age + health” consists of 3 week sessions of one hour each, based on walking and aerobic exercises. The control group had, at its first evaluation, the followings characteristics: average body mass 68kg±15, 28±5 BMI, 37%±5 body fat, 2.2kg±0.4 bone mass, 42%±9 lean body mass and did 129 repetitions ± 46 on a 2-Minute Step Test (2MST). The assessment of anthropometric and morphological variables was measured through an electrical bioimpedance scale (TANITA - BC 545). Aerobic endurance was evaluated from a 2MST.RESULTS In the control group only the percentage of body fat changed significantly, and increased over time. In the experimental group we found a positive relationship between PAP and the majority of morphological variables. The percentage of variation changed in: body fat (-4.3%±7.6, p=0.014), bone mass (2.4%±3.1, p=0.004) and 2MST (33.6%±63.1, p=0.023). In the remaining variables there were no significant modifications. The significant modification in 2MST after the activity period means that the aerobic performance can be improved in elderly, and attenuates the negative effects of age. Moreover, the benefits of PAP can be seen by positive alterations registered in lean body mass and in the percentage of body fat.

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Diseases, pests and environmental constraints pose a major threat to the sustainability of banana production globally. To address these challenges, the discovery and study of new sources of genetic resistance and adaptability are required, along with the general conservation of diversity. The Solomon Islands, located in the south-western Pacific region near Papua New Guinea, are a major center of banana diversity. Some collections had been made by nationals of some of the diversity present but little was known internationally of the rich genetic resource present. Two separate visits to the Solomon Islands characterized banana collections, documented and collected germplasm, recommended conservation strategies and provided training in cultivar characterization. A remarkable range of genetic diversity was found, including: many AA and AAA cooking types somewhat like those present in Papua New Guinea; nine Fei cultivars in relatively common usage, and two undescribed wild species as well as five AAB Pacific Plantains and four ABB cooking bananas belonging to the Kalapua subgroup. About six of the unique cultivars were successfully collected and established in the regional in vitro germplasm collection of SPC in Suva, Fiji. Nine Solomon Islanders were trained in the finer points of characterizing banana cultivars. Further collecting and study/evaluation of this rich diversity will promote its appreciation and potential utilization for meeting the challenges and opportunities ahead. Future studies could also determine the spread of the Awawe species and variability of morphological traits in the population. Community-based conservation could promote awareness of dietary diversity for better nutrition, via using the Fei bananas described in this paper. Establishing a virus-free regional field collection could help in comprehensively characterizing and evaluating regional Musa genetic resources. Existing sites could embrace the broader unique diversity of the Solomon Islands, and facilitate sharing this diversity in conjunction with a regional virus-tested in vitro collection.

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Dissertação de Mestrado, Biodiversidade e Biotecnologia Vegetal, 6 de Julho de 2016, Universidade dos Açores.

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Rutilus frisii Kutum is one of the most precious fish in the Caspian Sea. Investigation of the various aspects of its biocharactristics. Including its parasite fauna and ecological aspects are of prime importance. In this study the farmed kutum fry were on the focus of investigation in various seasons of the year and prior to their being released in the sea. This included also the study on the kutum spawners caught both from liver and the sea. The results were that 17 external and internal parasite species were distinct within different organs which were further identified down to genus and species. The single celled parasites identified included Ichthyophthirius multifilils, Chilodonella hexastica, Chilodonella pisicola, Trichodina sp Along with the monogene parasites that included Paradiplozoon chazaricum, D. rarissimus, D. turaliensis, D. nybelini, Dactylogyrus frisii. Meanwhile Diplostomum spathaceum constituted the single eyed parasites and the intestinal termatode were Aspidogaster limacoides, Asymphyoldora kubanicum as well as Bothriocephalus gowkongeniss as the sestads. The nematodes defrentiated were Raphidascaris acus, Dioctophyma renale, and Eustrongylides excisus followed by Lernaea cyprinacea as a crustacean. In this study, infestations by single celled parasites, crustaceans and sestod were found to be present only among the farmed kutum fry which varied in terms of percentage and intensity of infection as well as the parasite species and season of the year. The highest percentage of infection among kutum fry and spawners in both fresh water and in the sea during all seasons belonged to monogene parasites (33%). This was up to 100% among spawners. Infection caused by nematodes was exclusively detected among riverine spawners (7.5-5%) and the infection by Asymphyoldora kubanicum and Aspidogaster limacoides among Spawners caught at Sea and rivers varied within different seasons of the year. The infestation of Metacercer diplostomum spathaceum among kutum fry was 12% which compared to spawners was in slightly higher level. The study could identify Dioctophyma renale for the first time in the country and Eustrongylidis excisu was also detected among Rutilus frisii kutum.

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In the present study, natural occurrence of fungi and aflatoxin B1 (AFB1) in pellet feed and feed ingredients used for rainbow trout was investigated with emphasis to Aspergillus section Flavi members and medicinal plants inhibitory to Aspergillus growth and/or AF production. The feed samples were cultured on the standard isolation media including dichloran rosebengal chloramphenicol agar (DRCA) and Aspergillus flavus/parasiticus agar (AFPA) for 2 weeks at 28 °C. Identification of fungal isolates was implemented based on the macro- and microscopic morphological criteria. AFs were detected using high performance liquid chromatography (HPLC). Based on the results obtained, a total of 109 fungal isolates were identified of which Aspergillus was the prominent genus (57.0%), followed by Penicillium (12.84%), Absidia (11.01%) and Pseudallscheria (10.10%). The most frequent Aspergillus species was A. flavus (60.66%) isolated from all the feed ingredients as well as pellet feed. Among 37 A. flavus isolates, 19 (51.35%) were able to produce AFB1 on yeast extract-sucrose (YES) broth in the range of 10.2 to 612.8 [tg/g fungal dry weight. HPLC analyses of trout feed showed that pellet feed and all feed ingredients tested except gluten were contaminated with different levels of AFB1 in the range of 1.83 to 67.35 lig/kg. In order to finding natural inhibitors of fungal growth and/or AF production, essential oils (EOs) and extracts of 49 medicinal plants were studied against an aflatoxin-producing A. parasiticus using a microbioassay technique. The EOs was analyzed by gas chromatography/mass spectrometry (GC/MS). Based on the results obtained, Achillea millefolium sub sp. elborsensis, Ferula gummosa, Mentha spicata, Azadirachta indica, Conium maculatum and Artemisia dracunculus remarkably inhibited A. parasiticus growth without affecting AF production by the fungus. Besides of Thymus vulgaris and Citrus aurantifolia, the EO of Foeniculum vulgare significantly inhibited both fungal growth (-70.0%) and AFs B1 and G1 (-99.0%) production. The EO of Carum carvi and ethyl acetate extract of Platycladus orientalis suppressed AFs B1 and G1 by more than 90.0%, without any obvious effect on fungal growth. The IC50 values of bioactive plants for AFs B1 and G1 were determined in the ranges of 90.6 to 576.2 and 2.8 to 61.9 µg/ml, respectively. Overall, results of the present study indicate the importance of AF contamination of trout feed as a risk factor for fish farming and thus, an urgent necessity for constant monitoring of trout feed for any unacceptable levels of AF contamination. Likewise, antifungal activities of bioactive plants introduced here would be an important contribution to explain the use of these plants as effective antimicrobial candidates to protect feeds from toxigenic fungus growth and subsequent AF contamination.

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Phenotypic variation in plants can be evaluated by morphological characterization using visual attributes. Fruits have been the major descriptors for identification of different varieties of fruit crops. However, even in their absence, farmers, breeders and interested stakeholders require to distinguish between different mango varieties. This study aimed at determining diversity in mango germplasm from the Upper Athi River (UAR) and providing useful alternative descriptors for the identification of different mango varieties in the absence of fruits. A total of 20 International Plant Genetic Resources Institute (IPGRI) descriptors for mango were selected for use in the visual assessment of 98 mango accessions from 15 sites of the UAR region of eastern Kenya. Purposive sampling was used to identify farmers growing diverse varieties of mangoes. Evaluation of the descriptors was performed on-site and the data collected were then subjected to multivariate analysis including Principal Component Analysis (PCA) and Cluster analysis, one- way analysis of variance (ANOVA) and Chi square tests. Results classified the accessions into two major groups corresponding to indigenous and exotic varieties. The PCA showed the first six principal components accounting for 75.12% of the total variance. A strong and highly significant correlation was observed between the color of fully grown leaves, leaf blade width, leaf blade length and petiole length and also between the leaf attitude, color of young leaf, stem circumference, tree height, leaf margin, growth habit and fragrance. Useful descriptors for morphological evaluation were 14 out of the selected 20; however, ANOVA and Chi square test revealed that diversity in the accessions was majorly as a result of variations in color of young leaves, leaf attitude, leaf texture, growth habit, leaf blade length, leaf blade width and petiole length traits. These results reveal that mango germplasm in the UAR has significant diversity and that other morphological traits apart from fruits can be useful in morphological characterization of mango.