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Basal Diameter (basal + diameter)
Selected AbstractsOntogenetic scaling of scansorial surface area and setal dimensions of Chondrodactylus bibronii (Gekkota: Gekkonidae): testing predictions derived from cross-species comparisons of gekkotansACTA ZOOLOGICA, Issue 1 2009Nicole B. Webster Abstract Little is known of how the adhesive apparatus of gekkotans scales with growth. Cross-species comparisons of certain characteristics, using size as a comparator to investigate scaling relationships, suggest certain relationships between subdigital pad area and body size. The manner in which the adhesive apparatus grows and scales within any one species, however, remains unknown, and it is unclear whether interspecific and intraspecific patterns are similar. To address this, we examined a post-hatching ontogenetic series of the southern African gecko Chondrodactylus bibronii and demonstrate that setal density, setal basal diameter and setal spacing remain relatively constant in relation to size, indicating conserved subdigital pad assembly rules that are independent of size. Conversely, however, average and maximal setal lengths increase slightly and isometrically with size, an outcome that is probably explained by setal row recruitment, and the surface area of the subdigital pads scales close to, but below, isometry with respect to body mass and snout,vent length, it therefore does not increase sufficiently with size to compensate for the increase in mass. As a result, relative adhesive capacity decreases with growth with a regression slope of ,0.45. [source] Modelling rainfall interception loss in forest restoration trials in PanamaECOHYDROLOGY, Issue 3 2010Darryl E. Carlyle-Moses Abstract A modified Liu analytical model of rainfall interception (Ic) by tree canopies was evaluated using rainfall, throughfall and stemflow data collected from forest restoration trials in the Republic of Panama. The model uses an introduced approach to estimating the water storage capacities of tree boles, which has a more realistic physical basis than earlier iterations of the Liu model. Study species (Acacia mangium, Gliricidia sepium, Guazuma ulmifolia, Ochroma pyramidale, and Pachira quinata) were selected on the basis of differing leaf size and crown characteristics. Significant interspecific differences in both observed and simulated cumulative interception loss were found, with A. mangium intercepting more rainfall than other species. Errors between calculated and modelled cumulative Ic ranged from + 6·3% to + 30·5%, with modelled Ic always being the larger term. During-event evaporation rates from the study trees were positively related to tree height, crown area, and basal diameter. Crown area and the storage capacity of tree boles were negatively correlated. The results of a sensitivity analysis suggested that the modified model was most sensitive to variations in during-event evaporation rate. The implications of the model's sensitivity to during-event evaporation and the importance of this mechanism of interception loss are discussed, while suggestions are provided that may lead to further improvements to the analytical model. Copyright © 2010 John Wiley & Sons, Ltd. [source] Effects of moisture, nitrogen, grass competition and simulated browsing on the survival and growth of Acacia karroo seedlingsAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Keletso Mopipi Abstract The effects of irrigation, nitrogen fertilization, grass competition and clipping were investigated for one growing season at the research farm of the University of Fort Hare in the Eastern Cape Province of South Africa. The aim of the experiment was to assess the short-term performance of Acacia karroo seedlings under different environmental conditions and the implications of such factors on the long-term recruitment of plant species in savanna rangelands. There were no significant treatment effects on the survival of A. karroo seedlings. Using stem length and basal diameter as growth parameters, it was observed that irrigation enhanced both variables, while nitrogen fertilization did not have any significant effects. Clipping, grass competition and their interaction greatly suppressed the growth of the seedlings. Clipping increased the mean stem length when they were irrigated and fertilized. Control and fertilized plants had the highest stem length in the absence of grass competition, while grass competition combined with clipping resulted in the lowest stem length in both irrigated and nonirrigated plants. It was concluded that in the presence of grass competition, controlled browsing could be a viable solution to the problem of bush encroachment in savanna rangelands. Résumé Les effets de l'irrigation, d'une fertilisation à l'azote, de la compétition avec l'herbe et de la taille ont étéétudiés pendant une saison de croissance dans la ferme expérimentale de l'Université de Fort Hare, dans la Province du Cap oriental, en Afrique du Sud. Le but de l'expérience était d'évaluer les performances à court terme de jeunes plants d'Acacia karroo dans différentes conditions expérimentales, et les implications de ces facteurs sur le recrutement à long terme d'espèces végétales dans des pâturages de savane. Il n'y a pas eu d'effet significatif des traitements sur la survie des plants d'A. karroo. En utilisant la longueur des troncs et le diamètre de la base comme indicateurs de croissance, on a observé que l'irrigation augmentait les deux variables, alors que la fertilisation à l'azote n'avait aucun effet significatif. La taille, la compétition avec l'herbe et leur interaction supprimait fortement la croissance des jeunes plants. La taille augmentait la longueur moyenne des troncs lorsqu'ils étaient irrigués et fertilisés. Les plants témoins et les plants fertilisés avaient les troncs les plus longs en absence de toute compétition avec des herbes, alors que cette dernière, combinée avec la taille, aboutissait à la longueur la plus petite des troncs, chez les plants irrigués ou non. On en a conclu qu'en cas de compétition avec des herbes, un pâturage contrôlé pourrait être une solution viable au problème de l'envahissement des broussailles dans les pâturages de savane. [source] The Late Triassic Araucarioxylon Arizonicum trees of the Petrified Forest National Park, Arizona, USAPALAEONTOLOGY, Issue 1 2000Sidney R. Ash Examination and measurement of many of the trunks attributed to Araucarioxylon arizonicum Knowlton eroded from the Late Triassic Chinle Formation in the Petrified Forest National Park, Arizona demonstrate that the living tree did not closely resemble any of the present-day Araucaria trees of the southern hemisphere as postulated in past reconstructions. The research indicates that it was a tall monopodial tree with branches occurring in a disordered manner on the trunk from the base to the crown. Calculations using the allometric method of Niklas indicate that the trees were of considerable size. The largest recorded trunk has a basal diameter of nearly 3 m and may represent a tree 59 m high, when living. The root system of the A. arizonicum tree consisted of a ring of four to six steeply inclined lateral roots and a massive, vertically directed tap root. Many of the trunks still have their root systems attached, a circumstance that indicates their felling by the cut-bank operations of the local river system. The massive roots of these trunks, particularly the large tap root, are consistent with growth in soft, deep, alluvial soil, and the thin scale bark is to be expected in a tropical climate free from frost. [source] Is Helicobacter pylori related to endothelial dysfunction during childhood?PEDIATRICS INTERNATIONAL, Issue 2 2008Senol Coskun Abstract Background: Helicobacter pylori infection has been proposed to have a role in the development of atherosclerosis preceded by endothelial dysfunction. The aim of the present study was to determine if a relationship exists between H. pylori infection in childhood and endothelial dysfunction and level of high-sensitivity C-reactive protein (hsCRP). Methods: Between October 2003 and November 2004, 28 subjects who were anti- H. pylori IgG-positive and 25 who were anti- H. pylori IgG-negative were included in the study. Mean ages of the H. pylori -positive and negative groups were not significantly different. Endothelial functions were evaluated on Doppler ultrasonography of the brachial artery. Percent ratio of the change in systolic diameter during hyperemic phase to the basal diameter was evaluated. Each subject's serum was tested for hsCRP, homocysteine and lipids. Results: Percent ratio of the change in systolic diameters during hyperemic phase to the basal diameter was not significantly different between the H. pylori -negative and -positive groups (P > 0.29). Mean levels of hsCRP were also not significantly different (1.48 ± 1.8 g/dL vs 2.35 ± 3.33 g/dL; P > 0.24). Similarly, serum levels of lipids and homocysteine were not significantly different (P > 0.05 for all lipids). Conclusions: Non-invasive techniques used in the present study were not indicative of early findings of atherosclerosis in H. pylori infection during childhood. Further studies are required to evaluate the relationship between early endothelial dysfunction and H. pylori infection in children with cardiovascular risk factors. [source] Northern Environment Predisposes Birches to Ozone DamagePLANT BIOLOGY, Issue 2 2007E. Oksanen Abstract: Ozone sensitivity of silver birch (Betula pendula Roth) has been thoroughly investigated since early 1990,s in Finland. In our long-term open-field experiments the annual percentage reduction in basal diameter and stem volume increment were the best non-destructive growth indicators for ozone impact when plotted against AOTX. Remarkable differences in defence strategies, stomatal conductance, and defence compounds (phenolics), clearly indicate that external exposure indices are ineffective for accurate risk assessment for birch. For flux-based approaches, site-specific values for gmax and gdark are necessary, and determinants for detoxification capacity, ageing of leaves, and cumulative ozone impact would be needed for further model development. Increasing CO2 seems to counteract negative ozone responses in birch, whereas exposure to springtime frost may seriously exacerbate ozone damage in northern conditions. Therefore, we need to proceed towards incorporating the most important climate change factors in any attempts for ozone risk assessment. [source] Sex-specific responses of Populus cathayana to drought and elevated temperaturesPLANT CELL & ENVIRONMENT, Issue 6 2008XIAO XU ABSTRACT Dioecious plant species represent an important component of terrestrial ecosystems. Yet, little is known about sex-specific responses to drought and elevated temperatures. Populus cathayana Rehd, which is a dioecious, deciduous tree species, widely distributed in the northern, central and southwestern regions of China, was employed as a model species in our study. In closed-top chamber experiments, sex-specific morphological, physiological and biochemical responses of P. cathayana to drought and different elevated temperatures were investigated. Compared with the controls, drought significantly decreased the growth and the net photosynthesis rate (A), and increased the intrinsic water use efficiency (WUEi), carbon isotope composition (,13C), and the malondialdehyde (MDA) and abscisic acid (ABA) contents in droughted plants. In contrast, elevated temperatures significantly promoted the growth and the A, but decreased the WUEi, ,13C, MDA and ABA contents in well-watered individuals. When compared with males, elevated temperatures induced well-watered females to express a greater increase in the height growth (HG), basal diameter (BD), leaf area (LA), total number of leaves (TNL), dry matter accumulation (DMA) and specific leaf area (SLA), and a lower decrease in the A value, transpiration (E), stomatal conductance (gs), MDA and ABA contents, while elevated temperatures induced drought-stressed females to exhibit lower values of HG, BD, LA, TNL, DMA, A, E, gs and the intercellular CO2 concentration (Ci), and higher levels of SLA, WUEi, ,13C, MDA and ABA contents. Our results indicated that the female individuals of P. cathayana are more responsive and suffer from greater negative effects than do males when grown under environments with increased drought stress and elevated temperature. [source] 4262: MLPA of choroidal melanomaACTA OPHTHALMOLOGICA, Issue 2010BE DAMATO Purpose To determine the genotypic profiles of choroidal melanomas using multiplex ligation-dependent probe amplification (MLPA) and to correlate findings with clinical and pathological features and metastatic death. Methods DNA samples from 452 choroidal melanomas were analyzed with MLPA evaluating 31 loci on chromosomes 1, 3, 6 and 8. The MLPA results were correlated with survival predictors and wiht metastatic death. Results The patients (194 female; 258 male) had a median age of 59.4 years and a median follow-up of 1.89 years. Metastatic death occurred in 47 patients, correlating most strongly with concurrent chromosomes 3 losses and chromosome 8q gains (Logrank analysis, p<0.001). Many small choroidal melanomas with a basal diameter of less than 10mm showed only chromosome 3 loss or chromosome 8q gain or none of these, suggesting that their tumour was 'pre-lethal' at the time of ocular treatment. Conclusion MLPA analysis of choroidal melanoma is predictive of metastatic death and, therefore, clinically useful. The findings of this study are most consistent with evolutionary clonal abnormality, suggesting that timely treatment prevents the metastatic genotype and metastatic spread in a proportion of patients. [source] An audit of eccentrically-positioned ruthenium plaque radiotherapy of choroidal melanoma in LiverpoolACTA OPHTHALMOLOGICA, Issue 2009A RUSSO Purpose Brachytherapy is usually administered with the plaque overlapping the entire tumour margin by at least 1-2mm. With posterior tumours, our practice is to position the plaque with its posterior edge aligned with the posterior tumour margin. We audited ocular outcomes after eccentrically-placed ruthenium plaque radiotherapy of choroidal melanoma. Methods Patients were included if receiving primary ruthenium brachytherapy for choroidal melanoma during the three years up to the 31st July 2007. A perforated template was used to facilitate plaque positioning. For posterior tumors, the template was positioned so that trans-illumination produced a glow at the posterior tumour margin (,sunset sign'). Minimum doses of 300-350 Gy and 80-90 Gy were prescribed to the sclera and apex, respectively. Results The cohort comprised 162 patients (93 female and 69 male). The time to the last known visual acuity had a median of 23 months. The initial visual acuity was 20/40 or better in 94.6%, 20/60 to 20/200 in 13.0% and worse than 20/200 in 1.9% of patients. The tumours had a mean basal diameter of 11.7mm. Ten tumours exceeded 5.4 mm in height. Tumour extension to within 5mm of optic disc, fovea or both occurred in 18 (11.1%), 28 (17.3%) and 27 (16.7%) cases respectively. Risk factors for visual loss were proximity to optic disc or fovea, initial visual acuity worse than 20/40 and tumour height exceeding 5.4 mm. In 66 patients with none of these risk factors, 92% retained 20/40 or better and 5 had vision of 20/60 , 20/200. In 72 with one risk factor, 74.3% retained 20/16 , 20/40 and 95.7% had vision of 20/200 or better. In 12 patients with 2 risk factors, these percentages were 25.0% and 91.7%. Only 3 patients had 3 risk factors and one retained vision of 20/200 or better. Tumours distanced < 5 mm to fovea were divided in 3 groups, and visual acuity analysed. Three patients had local tumour recurrence and were treated respectively by proton beam radiotherapy, plaque radiotherapy and enucleation (the only eye lost in this series). Conclusion Eccentric plaque radiotherapy of choroidal melanoma achieves good rates of local tumour control, ocular retention and preservation of vision. [source] Revisiting the value of assessing the mitotic rate of choroidal melanomaACTA OPHTHALMOLOGICA, Issue 2009SE COUPLAND Purpose To re-evaluate mitotic rate (MR) as an indicator of malignancy grade in uveal melanoma (UM) and as a predictor for UM-related mortality. Methods UM patients treated 1993-2006 by local resection or enucleation were included. Data on largest basal diameter (LBD), ciliary body involvement, extraocular extension, cell type, closed loops, MR per 40/HPF, cytogenetics were collected. Mortality data were obtained from NHS Cancer Registry. Results 918 patients (520 M; 398 F) had median age of 64.6 yrs with a median follow-up of 3.46 yrs (range 0.02-13). The UM had mean diameter of 14.9 mm with ciliary body involvement in 43.0%, epithelioid cells in 63.3%, closed loops in 41.2%, extraocular spread in 11.3%. Cytogenetics in 337 patients showed disomy 3 and 8 in 27%, monosomy 3 in 10.7%, chromosome 8 gains in 24.0%, both these abnormalities in 38.3%. The median MR was 3(range 0-61, SD 6). High MR correlated with ciliary body involvement (p = 0.001), epithelioid cells(p = 0.009), closed loops(p<0.0001), extraocular spread(p=0.027) & monosomy 3(p<0.0001;Mann-Whitney). MR also correlated with LBD(p=0.0001; t-test). Metastatic death occurred in 243 patients (26.7%). Kaplan-Meier analysis showed MR >4/40 HPF to be associated with increased 10-year metastatic mortality from 32.5 (95% confidence intervals [CI] 25.7-39.3) to 65.5 (95% CI 55-7-75.4; log rank statistic 53.28, p<0.0001). Cox multivariate analysis showed MR to be an independent predictive factor for metastatic death (p<0.0001). MR was predictive of metastatic death also in patients without detectable monosomy 3 (Log rank statistic 10.38, p = 0.002). Conclusion MR correlates with other known risk factors for metastatic death and independently predicts mortality even when cytogenetics show disomy 3. [source] |