49 research outputs found
Notes on Discriminating Morphological Characters for Generic and Sectional Classification of Musaceae in Thailand
ABSTRACTMorphological characters have been used effectively in classification of the banana family, Musaceae. Most taxonomic features are qualitative characters which require experience in evaluation and are subjected to individual opinions. On the other hand, though not many, quantitative characters can be directly measured on sites or from photographs. The objective of this study was to evaluate efficiency of these quantitative features in the classification of the banana family in Thailand. A total of 16 quantitative morphological characters of 143 accessions from 10 native taxa and one introduced Musella species were assessed. All quantitative data were evaluated by box-plot analysis, principal component analysis and discriminant analysis. It was found that the quantitative data are useful in the classification at the generic level in Musaceae and at the sectional level of Musa. All three genera can be distinguished by pseudostem height, number of sucker plants and fruit pedicel length. At sectional level, number of fruit rows on mid hand can separate the sections Rhodoclamys and Callimusa from Musa and leaf blade length can differentiate Rhodoclamys from Callimusa. Interestingly, fruit pedicel length and fruit apex length which were used in Musa acuminata descriptors at subspecific level were not significantly different in this study.Keywords: Characterization, Morphometrics, Musaceae, Numerical Taxonomy, Phenetic analysi
Mangrove dynamics and environmental changes on Koh Chang, Thailand during the last millennium
Continued adaptation of C4 photosynthesis after an initial burst of changes in the andropogoneae grasses
C4 photosynthesis is a complex trait that sustains fast growth and high productivity in tropical and subtropical conditions and evolved repeatedly in flowering plants. One of the major C4 lineages is Andropogoneae, a group of ∼ 1,200 grass species that includes some of the world's most important crops and species dominating tropical and some temperate grasslands. Previous efforts to understand C4 evolution in the group have compared a few model C4 plants to distantly related C3 species, so that changes directly responsible for the transition to C4 could not be distinguished from those that preceded or followed it. In this study, we analyse the genomes of 66 grass species, capturing the earliest diversification within Andropogoneae as well as their C3 relatives. Phylogenomics combined with molecular dating and analyses of protein evolution show that many changes linked to the evolution of C4 photosynthesis in Andropogoneae happened in the Early Miocene, between 21 and 18 Ma, after the split from its C3 sister lineage, and before the diversification of the group. This initial burst of changes was followed by an extended period of modifications to leaf anatomy and biochemistry during the diversification of Andropogoneae, so that a single C4 origin gave birth to a diversity of C4 phenotypes during 18 million years of speciation events and migration across geographic and ecological spaces. Our comprehensive approach and broad sampling of the diversity in the group reveals that one key transition can lead to a plethora of phenotypes following sustained adaptation of the ancestral state
Cardiac Biomarker Release After Exercise in Healthy Children and Adolescents: A Systematic Review and Meta-Analysis.
PURPOSE: The authors evaluated the impact of acute exercise and 24-hour recovery on serum concentration of cardiac troponins T and I (cTnT and cTnI) and N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) in healthy children and adolescents. The authors also determined the proportion of participants exceeding the upper reference limits and acute myocardial infarction cutoff for each assay. METHOD: Web of Science, SPORTDiscus, MEDLINE, ScienceDirect, and Scopus databases were systematically searched up to November 2017. Studies were screened and quality-assessed; the data was systematically extracted and analyzed. RESULTS: From 751 studies initially identified, 14 met the inclusion criteria for data extraction. All 3 biomarkers were increased significantly after exercise. A decrease from postexercise to 24 hours was noted in cTnT and cTnI, although this decrease was only statistically significant for cTnT. The upper reference limit was exceeded by 76% of participants for cTnT, a 51% for cTnI, and a 13% for NT-proBNP. Furthermore, the cutoff value for acute myocardial infarction was exceeded by 39% for cTnT and a 11% for cTnI. Postexercise peak values of cTnT were associated with duration and intensity (Q(3) = 28.3, P < .001) while NT-proBNP peak values were associated with duration (Q(2) = 11.9, P = .003). CONCLUSION: Exercise results in the appearance of elevated levels of cTnT, cTnI, and NT-proBNP in children and adolescents. Postexercise elevations of cTnT and NT-proBNP are associated with exercise duration and intensity
Cardiac Biomarker Release after Endurance Exercise in Male and Female Adults and Adolescents.
OBJECTIVES: To compare the responses of high-sensitivity cardiac troponin T (hs-cTnT) and NH2-terminal probrain natriuretic peptide (NT-proBNP) after 60 minutes of swimming in male and female adults and adolescents with different pubertal status. STUDY DESIGN: Adolescent swimmers (25 male and 25 female) and adult swimmers (7 male and 9 female) participated in a 60-minute maximal swimming test with serial assessment of hs-cTnT and NT-proBNP at rest, immediately postexercise, and at 1, 3, 6, 12, and 24 hours postexercise. Adolescents were classified according to pubertal status: Tanner stages 3 (n = 14), 4 (n = 22), and 5 (n = 14). RESULTS: Exercise resulted in an increase in both biomarkers. hs-cTnT responses to exercise were similar in adolescents with different pubertal status and adults, although there was substantial individual variability in peak hs-cTnT, with the upper reference limit exceeding in 62% of the participants. Postexercise kinetics for hs-cTnT were largely consistent across all groups with a return to near baseline levels 24 hours postexercise. The male participants showed higher values of hs-cTnT at baseline and postexercise. All groups had similar NT-proBNP responses to acute exercise and recovery. One swimmer exceeded the upper reference limit for NT-proBNP. CONCLUSIONS: An exercise-associated increase in hs-cTnT and NT-proBNP occurred in response to a 60-minute maximal swimming test that was independent of pubertal status/adolescent vs adults. The present data also suggests that baseline and postexercise hs-cTnT values are higher in male compared with female, with no sex differences in NT-proBNP values
Alteração de biomarcadores de lesão miocárdica em atletas após a Maratona Internacional de São Paulo
Revisiting the morphology, microstructure, and properties of cellulose fibre from pineapple leaf so as to expand its utilization
Pineapple leaf waste is an agricultural product that is available in large quantities and is still under-utilized. Therefore, the aim of this work was to investigate the morphology, microstructure, and mechanical properties of pineapple leaf fibre (PALF) such that its full potential may be realized. Pineapple leaf, its fibre bundles and elementary fibres have been investigated. Morphology, size, and mechanical properties of fibre bundles extracted from different parts (i.e. bottom, middle and top) of a leaf were studied. It was found that the PALF obtained from vascular tissue and from the mesophyll have different macroscopic shapes. Both, however, contain micron-size elementary fibres of similar size and shape. Size and properties of fibre bundles change from the bottom end of a leaf toward the top end. Pineapple leaf microfibre (PALMF) was found to be smaller in diameter than other natural fibres. It is also very long and its structure changes according to its position along the leaf. At the bottom end a clear and large central hole or lumen can be observed. At the top the lumen becomes almost undetectable. The mechanical strength of PALMF appears to decrease, albeit very slightly, toward the tip of the leaf. The mechanical properties of the fibres are relatively high and comparable to that of flax and hemp fibres which are widely studied and used as reinforcing materials in composites. Very long microfibre can easily be obtained from fibre bundles by dissolving the binding matrix. Potential applications for this microfibre are suggested
A new species of Argyreia (Convolvulaceae) from Thailand
Argyreia pseudosolanum Traiperm & Suddee, sp. nov. from the NE region of Thailand is described and illustrated. The new species is remarkable in having a very distinctive corolla shape similar to Solanum, and staminal filament bases glabrous or nearly glabrous with a few multicellular, uniseriate hairs at the attachment point on the corolla tube. Detailed descriptions, illustrations, a summary of the ecology and an IUCN conservation status are provided