977 resultados para Growth And Development


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The black tern (Anous minutus) uses a semi-precocial growth strategy. Terrestrial locomotor capacity occurs soon after hatching, but pectoral limb development is delayed and flight is not possible until about post-hatching day 50. A growth series (hatchlings to fledglings) was used to explore how limb musculoskeletal development varied with body mass. In the pelvic limb, bone lengths scaled isometrically or with negative allometry. Gastrocnemius muscle mass and the failure load and stiffness of the tibiotarsus scaled isometrically. In the pectoral limb, pectoralis and supracoracoideus muscle masses increased with strong positive allometry that was mirrored by increases in wing bone strength and stiffness. Bending strength (σult) and modulus (E) remained fairly constant throughout development to fledging for all limb bones. The moment of inertia (I) scaled with negative allometry for the tibiotarsus and with strong positive allometry in the wing bones. Differences in σult and E of the tibiotarsus between pre-fledged chicks and adults was due, primarily, to increases in bone density rather than increases in the moment of inertia of the skeletal elements, whereas σult of wing bones was a function of increases in both bone density and I. Early development of functional pelvic limbs in tree-nesting birds is relatively unusual, and presumably reflects a familial trait that does not appear to compromise breeding success in this species.

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The red-tailed phascogale ( Phascogale calura) is an endangered dasyurid species that has recently been brought into captivity in an effort to increase numbers before release back into the wild. As part of investigations into the reproductive biology of the species, information on the growth and development of young was collected throughout lactation from litters raised in three separate colonies. Growth curves for aging young throughout lactation and a timetable of developmental changes were constructed. While two colonies, with fourth- and fifth-generation captive animals, showed no significant difference in growth, animals from a third colony that had been wild caught before breeding displayed a slower rate of growth from 34 days of age. The pattern of development resembled that of other dasyurids, with young left in the nest from 44 days of age, fully furred by 78 days and weaned between 90 and 110 days. Captive phascogales invest heavily in their young, with litters weighing 380 +/- 67% of maternal bodyweight at weaning.

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The changes of the concentration of iron in the growth substrates and the sporophores of Agaricus bisporus (Lange) Pilat that occurred during culture under standard commercial conditions, were observed using atomic absorption spectrophotometry and iron-59 radiotracing techniques. The routes of translocation and sites of iron accumulation within the sporophore were shovn to alter during development and by the use of novel, pelletised substrates the concentration of iron in the mycelium of the substrates and in developing sporophores was observed during culture. Findings indicated that the compost was the major source of iron and that the concentration of iron in the compost mycelium varied cyclically in relation to the periodic appearance of sporophores. In the casing layer the mycelium is organised into strands which are responsible for the movement of iron from the compost into developing sporophores. A photographic technique for estimating sporophore growth rates showed that the accumulation of iron was not concomitant with sporophore growth and this was attributable to a declining quantity of available iron in the compost mycelium during sporophore growth. Variations in the quantity of iron in sporophores resulted primarily from differences in the quantity of water soluble iron in the compost but, the productivity of the crop, the type of casing layer and differences in watering also influenced sporophore composition. Changes in the concentration of extractable iron in the compost and casing layer throughout culture were related to mycelial activity and to a lesser extent were influenced by watering and the bacterial populations of the casing layer. Thus, the findings of this study give some indication of the relative importance that different cultural conditions exert over sporophore composition together with demonstrations of the movement of a single material within the sporophores and substrates during the cultivation of Agaricus bisporus.

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To further investigate the importance of insulin signaling in the growth, development, sexual maturation and egg production of adult schistosomes, we have focused attention on the insulin receptors (SjIRs) of Schistosoma japonicum, which we have previously cloned and partially characterised. We now show, by Biolayer Interferometry, that human insulin can bind the L1 subdomain (insulin binding domain) of recombinant (r)SjIR1 and rSjIR2 (designated SjLD1 and SjLD2) produced using the Drosophila S2 protein expression system. We have then used RNA interference (RNAi) to knock down the expression of the SjIRs in adult S. japonicum in vitro and show that, in addition to their reduced transcription, the transcript levels of other important downstream genes within the insulin pathway, associated with glucose metabolism and schistosome fecundity, were also impacted substantially. Further, a significant decrease in glucose uptake was observed in the SjIR-knockdown worms compared with luciferase controls. In vaccine/challenge experiments, we found that rSjLD1 and rSjLD2 depressed female growth, intestinal granuloma density and faecal egg production in S. japonicum in mice presented with a low dose challenge infection. These data re-emphasize the potential of the SjIRs as veterinary transmission blocking vaccine candidates against zoonotic schistosomiasis japonica in China and the Philippines.

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Awnless barnyard grass, feathertop Rhodes grass, and windmill grass are important weeds in Australian cotton systems. In October 2014, an experiment was established to investigate the phenological plasticity of these species. Seed of these species were planted in a glasshouse every four weeks and each cohort grown for 6 months. A developmental response to day length was observed in barnyard grass but not in the other species. Days to maturity increased with each planting for feathertop Rhodes and windmill grass for the first six cohorts. Barnyard grass showed a similar pattern in growth for seeds planted from October to December with an increase in the onset of maturity from 51 to 58 days. However, the onset of maturity for cohorts planted between January and March decreased to between 50 and 52 days. All species had a decrease in the total number of panicles produced from the first four plantings. Feathertop Rhodes grass planted in October produced 41 panicles compared to those planted at the end of December producing 30 panicles, barnyard grass had a decrease from 99 to 47 panicles and windmill grass 37 to 15 panicles on average. By comparing the development of these key weed species over 12 months, detailed information on the phenological plasticity of these species will be obtained. This information will contribute to more informed management decisions by improving our understanding of appropriate weed control timings or herbicide rates depending on weed emergence and development.

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O objetivo do presente trabalho foi testar a influência de quatro dietas alimentares sobre o crescimento populacional, desenvolvimento, comprimento total, peso seco e valor nutricional de duas espécies zooplanctônicas, Moina micrura and Diaphanosoma birgei, com os seguintes tratamentos alimentares: somente alga (A), alga + vitaminas (AV), alga + ração (AR) e alga + ração + vitaminas (ARV). O pico de crescimento para as duas espécies estudadas ocorreu mais rápido no tratamento AV. em geral, o tratamento AV para M. micrura mostrou melhores resultados para taxa intrínseca, fecundidade, desenvolvimento embrionário e pós-embrionário. Já a longevidade e número total de desovas apresentaram melhores resultados no tratamento AR (p < 0,05). Para D. birgei, os melhores resultados foram obtidos nos tratamentos contendo ração e vitamina (p < 0,05). A maior porcentagem de proteínas e lipídeos para os dois cladóceros ocorreu nos tratamentos contendo ração, já o carboidrato foi maior no tratamento contendo somente alga (p < 0,05). em geral, as dietas contendo ração e vitamina apresentaram os melhores resultados para o desenvolvimento dos cladóceros, com qualidade de água adequada para cultivo, podendo ser utilizadas em culturas com altas concentrações em laboratório.

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ABSTRACT The ground pearl, Eurhizococcus brasiliensis, is considered an important pest of vineyards in southern Brazil, with affected plants exhibiting leaf chlorosis, reduction in vigor, fading, and death. This study evaluated the quality of hardwood cuttings produced from plants infected (I) and not infected (NI) by ground pearl. ?Paulsen 1103? (Vitis berlandieri × Vitis rupestris) plants were grown for 29 months in brick-built raised beds either infested or not infested by ground pearl; then, 12 one-year-old branches with a maximum of 12 buds each were cut from each plant, subdivided into three portions (4 buds cutting-1), and subjected to destructive and nondestructive testing. Destructive testing comprised determining fresh and dry weight, length, internode diameters, and percentage of starch. Nondestructive testing comprised assessing the potential for bud sprouting and shoot development. Each mother plant in the I and NI beds was considered a replicate, with a total of 360 cuttings per treatment. It was observed that cuttings from infected plants had significantly lower (P<0.05) internode diameter, length, and fresh and dry weight than those of the uninfected plants. The percentage of starch content of the cuttings did not differ significantly. All cuttings showed the same percentage (100%) of bud breaking and no changes in growth and development of seedlings regardless of source. Given these results, it was concluded that vines of ?Paulsen 1103? infested with ground pearl produce smaller cuttings than those of uninfected plants but with no reduction in bud break percentage or seedling development. Key words: Margarodidae, Vitaceae, insect?plant interaction, carbohydrates. RESUMO A pérola-da-terra, Eurhizococcus brasiliensis, tem sido considerada uma importante praga dos vinhedos no sul do Brasil, sendo que as plantas atacadas manifestam clorose foliar, redução no vigor, definhamento e morte. Este trabalho teve por objetivo avaliar a qualidade de estacas lenhosas produzidas a partir do contraste de videiras infestadas (I) e não infestadas (NI) por pérola-da-terra. Após 29 meses de cultivo em canteiros de alvenaria, em presença ou ausência de pérola-da-terra, cada planta da variedade ?Paulsen 1103? (Vitis berlandieri × Vitis rupestris) foi submetida à retirada de 12 ramos de ano, com no máximo 12 gemas cada, sendo subdivididos em três porções 4 gemas estaca-1) e submetidos a avaliações destrutivas e não destrutivas. As destrutivas consistiram em determinar massas fresca e seca, comprimento, diâmetro de entrenós e percentual de amido. As avaliações não estrutivas consistiram em testar o potencial de brotação e desenvolvimento das estacas. Cada planta matriz dos canteiros I e NI foi considerada uma repetição, totalizando 360 estacas por tratamento. As estacas das plantas infestadas tiveram uma redução (P<0,05), em relação às não infestadas, em diâmetro, comprimento e massas fresca e seca. Não houve contraste significativo do percentual de amido avaliado das estacas. Quanto à brotação, destaca-se que todas as estacas apresentaram o mesmo percentual (100%), independente da origem, sem alterações no desenvolvimento e crescimento das mudas. Diante desses resultados, salienta-se que videiras ?Paulsen 1103? infestadas por pérola-da-terra produzem estacas menores, porém não há comprometimento no percentual de brotação e desenvolvimento das mudas, quando comparadas com plantas não infestadas. Palavras-chave: Margarodidae, Vitaceae, interação inseto-planta, carboidrato

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Film greenhouse claddings are typically used to protect horticultural crops from low temperature and high rainfall conditions. However, a range of novel plastic films have been developed which filter specific radiation wavelengths with the aim of providing the grower with greater control of crop growth and development. A replicated experiment was conducted in 8 small experimental greenhouses, covered with different photoselective films characterised by a range of red/far-red ratios and PAR transmissions to study their effects on the growth, yield and quality of the strawberry cv. 'Elsanta'. Marketable yield per plant was 51% greater under the film with the highest light transmission (control) compared with the lower light transmission films. Similarly, unmarketable fruit number and average non-marketable individual fruit weight per plant was lowest under films with higher light transmissions and higher under lower light transmission films. Cropping duration was longer under films with high R/FR. Also plants under high R/FR were more compact (due to shorter petiole lengths) compared to plants grown under low R/FR. The results are discussed in relation to the increased use of photoselective films in protected horticulture and the need for higher quality fruit and vegetables.

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Background
Clinicians and policy makers need the ability to predict quantitatively how childhood bodyweight will respond to obesity interventions.

Methods
We developed and validated a mathematical model of childhood energy balance that accounts for healthy growth and development of obesity, and that makes quantitative predictions about weight-management interventions. The model was calibrated to reference body composition data in healthy children and validated by comparing model predictions with data other than those used to build the model.

Findings
The model accurately simulated the changes in body composition and energy expenditure reported in reference data during healthy growth, and predicted increases in energy intake from ages 5—18 years of roughly 1200 kcal per day in boys and 900 kcal per day in girls. Development of childhood obesity necessitated a substantially greater excess energy intake than for development of adult obesity. Furthermore, excess energy intake in overweight and obese children calculated by the model greatly exceeded the typical energy balance calculated on the basis of growth charts. At the population level, the excess weight of US children in 2003—06 was associated with a mean increase in energy intake of roughly 200 kcal per day per child compared with similar children in 1971—74. The model also suggests that therapeutic windows when children can outgrow obesity without losing weight might exist, especially during periods of high growth potential in boys who are not severely obese.

Interpretation
This model quantifies the energy excess underlying obesity and calculates the necessary intervention magnitude to achieve bodyweight change in children. Policy makers and clinicians now have a quantitative technique for understanding the childhood obesity epidemic and planning interventions to control it.

Funding
Intramural Research Program of the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases.

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OBJECTIVE: The purpose of the study was to evaluate the influence of the skeletal maturation in the mandibular and dentoalveolar growth and development during the Class II, division 1, malocclusion correction with Balters bionator. METHODS: Three groups of children with Class II, division 1, malocclusion were evaluated. Two of them were treated for one year with the bionator of Balters appliance in different skeletal ages (Group 1: 6 children, 7 to 8 years old and Group 2: 10 children, 9 to 10 years old) and the other one was followed without treatment (Control Group: 7 children, 8 to 9 years old). Lateral 45 degree cephalometric radiographs were used for the evaluation of the mandibular growth and dentoalveolar development. Tantalum metallic implants were used as fixed and stable references for radiograph superimposition and data acquisition. Student's t test was used in the statistical analysis of the displacement of the points in the condyle, ramus, mandibular base and dental points. Analysis of variance one-fixed criteria was used to evaluate group differences (95% of level of significance). RESULTS: The intragroup evaluation showed that all groups present significant skeletal growth for all points analyzed (1.2 to 3.7 mm), but in an intergroup comparison, the increment of the mandibular growth in the condyle, ramus and mandibular base were not statically different. For the dentoalveolar modifications, the less mature children showed greater labial inclination of the lower incisors (1.86 mm) and the most mature children showed greater first permanent molar extrusion (4.8 mm).