898 resultados para mean body length
Resumo:
Existem muitas controvérsias sobre a real interferência da respiração no crescimento craniofacial. Este estudo avaliou a possível relação da influência do padrão respiratório com as variáveis cefalométricas: 1) variáveis esqueléticas sagitais: convexidade do ponto A, profundidade facial, profundidade da maxila e comprimento do corpo mandibular; 2) variáveis esqueléticas verticais: altura facial inferior, eixo facial, cone facial, plano palatal, plano mandibular, altura facial posterior e arco mandibular; 3) variáveis dentárias: protrusão do incisivo inferior e protrusão do incisivo superior. A amostra constituiu-se de 120 crianças do sexo masculino e do sexo feminino com más-oclusões dentárias de Classe I e II-1, respiradores bucais e nasais na fase da dentadura mista e permanente, com indicação para tratamento ortodôntico. Após as avaliações ortodôntica, otorrinolaringológica e fonoaudiológica a amostra foi dividida em 2 grupos: 60 crianças portadoras de más-oclusões Classe I e Classe II-1 respiradoras bucais e 60 crianças portadoras de más-oclusões Classe I e Classe II-1 respiradoras nasais, sendo cada grupo divididos em 3 subgrupos nas faixas etárias: 7 a 8 anos, 9 a 10 anos e 11 a 12 anos. Após a obtenção dos resultados e a interpretação da análise estatística, foi possível concluir que: 1) das relações entre os padrões respiratórios (bucal e nasal) e as variáveis esqueléticas sagitais: constatou-se que houve diferença estatisticamente significante, apresentando-se as variáveis cefalométricas: Convexidade pto. A: aumentada no grupo de respiração bucal, idade de 7 a 8 anos com má-oclusão Classe I. Profundidade facial : aumentada no grupo de respiração bucal, idade de 9 a 10 anos com má-oclusão Classe II-1. Profundidade maxila: aumentada no grupo de respiração bucal, idade de 9 a 10 anos com má-oclusão Classe II-1; 2) das relações entre os padrões respiratórios (bucal e nasal) e as variáveis esqueléticas verticais: constatou-se que houve diferença estatisticamente significante, apresentando-se as variáveis cefalométricas: Cone facial: diminuída no grupo de respiração bucal, idade 9 a 10 anos com má-oclusão Classe I. Arco mandibular : diminuída no grupo de respiração bucal, idade 7 a 8 anos com má-oclusão Classe II-1.; 3) das relações entre os padrões respiratórios (bucal e nasal) e as variáveis dentárias: constatou-se que não houve diferença estatisticamente significante para nenhuma das variáveis dentárias analisadas: protrusão do incisivo inferior e superior , não se relacionando com os padrões respiratórios (bucal e nasal).
Resumo:
This study aimed to assess the effectiveness of a novel, community-based weight management programme delivered through general practitioner (GP) practices and community pharmacies in one city in the United Kingdom. This study used a non-randomized, retrospective, observational comparison of clinical data collected by participating GP practices and community pharmacies. Subjects were 451 overweight or obese men and women resident in areas of high socioeconomic deprivation (82% from black and minority ethnic groups, 86% women, mean age: 41.1 years, mean body mass index [BMI]: 34.5 kg m−2). Weight, waist circumference and BMI at baseline, after 12 weeks and after 9 months were measured. Costs of delivery were also analysed. Sixty-four per cent of participants lost weight after the first 12 weeks of the My Choice Weight Management Programme. There was considerable dropout. Mean percentage weight loss (last observation carried forward) was 1.9% at 12 weeks and 1.9% at final follow-up (9 months). There was no significant difference in weight loss between participants attending GP practices and those attending pharmacies at both 12 weeks and at final follow-up. Costs per participant were higher via community pharmacy which was attributable to better attendance at sessions among community pharmacy participants than among GP participants. The My Choice Weight Management Programme produced modest reductions in weight at 12 weeks and 9 months. Such programmes may not be sufficient to tackle the obesity epidemic.
Resumo:
During the 2004 growing season, five raspberry cultivars were evaluated in terms of their susceptibility to the raspberry cane midge (Resseliella theobaldi Barnes). The trial was carried out at Berkenye, Nógrád County, Hungary. The cultivars evaluated were ‘Rubaca’ from Germany, ‘Fertődi Zamatos’ from Hungary, ‘Tulameen’ from Canada, and ‘Autumn Bliss’ and ‘Golden Bliss’ from the United Kingdom. Every other week, twenty-five split primocanes of each cultivar were randomly collected for laboratory examination. Data recorded for each cultivar included the mean number of larvae, the mean split length, and the mean extent of bark peeling per primocane. Pearson’s linear correlation coefficients were calculated for the correlations between the annual mean number of larvae per primocane on the one hand, and the annual cumulative mean split length per primocane and annual mean extent of bark peeling per primocane on the other hand. There was a weak correlation between annual mean number of larvae and annual cumulative mean split length, and a stronger correlation between annual mean number of larvae and annual mean extent of bark peeling. Annual mean number of larvae per primocane and annual mean extent of bark peeling per primocane were both highest in ‘Rubaca’, which means that the number of larvae per cane largely depends on the extent of stem peeling, although longitudinal splitting may also play a role. Therefore, cultivars with hardly any bark peeling and few and small longitudinal splits can be presumed to be less susceptible to infestation by the raspberry cane midge. Using these criteria, the least susceptible of the five cultivars evaluated would be ‘Tulameen’ and ‘Fertődi Zamatos’. Further research is needed to confirm this conclusion and to gather data on other factors which affect cultivar choice for new plantations, including winter hardiness, and susceptibility to cane diseases.
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Insect biodiversity is unevenly distributed on local, regional, and global scales. Elevation is a key factor in the uneven distribution of insect diversity, serving as a proxy for a host of environmental variables. My study examines the relationship of Heteroptera (true bugs) species diversity, abundance, and morphology to elevational gradients and land-use regimes on Mt. Kilimanjaro, Tanzania, East Africa. Heteroptera specimens were collected from 60 research sites covering an elevational range of 3684m (866-4550m above sea level). Thirty of the sites were classified as natural, while the remaining 30 were classified as disturbed (e.g., agricultural use or converted to grasslands). I measured aspects of the body size of adult specimens and recorded their location of origin. I used regression models to analyze the relationships of Heteroptera species richness, abundance, and body measurements to elevation and land-use regime. Richness and abundance declined with greater elevation, controlling for land use. The declines were linear or logarithmic in form, depending on the model. Richness and abundance were greater in natural than disturbed sites, controlling for elevation. According to an interaction, richness decreased more in natural than disturbed sites with rising elevation. Body length increased as a quadratic function of elevation, adjusting for land use. Body width X length decreased as a logarithmic function of elevation, while leg length/body length decreased as a quadratic function. Leg length/body length was greater in disturbed than natural sites. Interactions indicated that body length and body width X length were greater in natural than disturbed sites as elevation rose, although the general trend was downward. Future research should examine the relative importance of land area, temperature, and resource constraints for Heteroptera diversity and morphology on Mt. Kilimanjaro.
Resumo:
Bedforms such as dunes and ripples are ubiquitous in rivers and coastal seas, and commonly described as triangular shapes from which height and length are calculated to estimate hydrodynamic and sediment dynamic parameters. Natural bedforms, however, present a far more complicated morphology; the difference between natural bedform shape and the often assumed triangular shape is usually neglected, and how this may affect the flow is unknown. This study investigates the shapes of natural bedforms and how they influence flow and shear stress, based on four datasets extracted from earlier studies on two rivers (the Rio Paraná in Argentina, and the Lower Rhine in The Netherlands). The most commonly occurring morphological elements are a sinusoidal stoss side made of one segment and a lee side made of two segments, a gently sloping upper lee side and a relatively steep (6 to 21°) slip face. A non-hydrostatic numerical model, set up using Delft3D, served to simulate the flow over fixed bedforms with various morphologies derived from the identified morphological elements. Both shear stress and turbulence increase with increasing slip face angle and are only marginally affected by the dimensions and positions of the upper and lower lee side. The average slip face angle determined from the bed profiles is 14°, over which there is no permanent flow separation. Shear stress and turbulence above natural bedforms are higher than above a flat bed but much lower than over the often assumed 30° lee side angle.
Resumo:
The genus Hemidactylus Oken, 1817 has cosmopolite distribution, with three species occurring in Brazil, two of them native, H. brasilianus and H. agrius, and one exotic, H. mabouia. Considering the studies about ecology of lizards conducted in the Ecological Station of the Seridó, from 2001 to 2011, this study aimed (1) to re-evaluate the occurrence of the species of Hemidactylus in this ESEC; (2) to analyze ecological and biological aspects of the H. agrius population; and (3) to investigate the current and potential distribution of the native species of the genus in northeastern Brazil, analyzing the suitability of ESEC to this taxon. For the first two objectives, a sampling area consisting of five transects of 200 x 20 m, was inspected in alternating daily shifts for three consecutive days, from August 2012 to August 2013. For the latter objective, occurrence points of H. agrius and H. brasilianus from literature and from the database of Herpetological Collections of the UFRN and the UNICAMP were consulted to build predictive maps via the Maximum Entropy algorithm (MaxEnt). In ESEC Seridó, 62 H. agrius individuals were collected (25 females, 18 males and 19 juveniles), and two neonates were obtained from a communal nest incubated in the laboratory. No record was made for the other two species of the genus. Hemidactylus agrius demonstrated to be a nocturnal species specialized in habitats with rocky outcrops; but this species is generalist regarding microhabitat use. In the population studied, females had an average body length greater than males, and showed higher frequencies of caudal autotomy. Regarding diet, H. agrius is a moderately generalist species that consumes arthropods, especially insect larvae, Isoptera and Araneae; and vertebrates, with a case of cannibalism registered in the population. With respect to seasonal differences, only the number of food items ingested differed between seasons. The diet was similar between sexes, but ontogenetic differences were recorded for the total volume and maximum length of the food items. Significant relationships were found between lizard body/head size measurements and the maximum length of prey consumed. Cases of polydactyly and tail bifurcation were recorded in the population, with frequencies of 1.6% and 3.1%, respectively. In relation xv to the occurrence points of the native species, 27 were identified, 14 for H. agrius and 13 for H. brasilianus. The first species presented restricted distribution, while the second showed a wide distribution. In both models generated, the ESEC Seridó area showed medium to high suitability. The results of this study confirm the absence of H. brasilianus and H. mabouia this ESEC, and reveal H. agrius as a dietary opportunist and cannibal species. Further, the results confirm the distribution patterns shown by native species of Hemidactylus, and point ESEC Seridó as an area of probable occurrence for the species of the genus, the establishing of H. brasilianus and H. mabouia are probably limited by biotic factors, a fact yet little understood
Resumo:
The world's oceans are slowly becoming more acidic. In the last 150 yr, the pH of the oceans has dropped by ~0.1 units, which is equivalent to a 25% increase in acidity. Modelling predicts the pH of the oceans to fall by 0.2 to 0.4 units by the year 2100. These changes will have significant effects on marine organisms, especially those with calcareous skeletons such as echinoderms. Little is known about the possible long-term impact of predicted pH changes on marine invertebrate larval development. Here we predict the consequences of increased CO2 (corresponding to pH drops of 0.2 and 0.4 units) on the larval development of the brittlestar Ophiothrix fragilis, which is a keystone species occurring in high densities and stable populations throughout the shelf seas of northwestern Europe (eastern Atlantic). Acidification by 0.2 units induced 100% larval mortality within 8 d while control larvae showed 70% survival over the same period. Exposure to low pH also resulted in a temporal decrease in larval size as well as abnormal development and skeletogenesis (abnormalities, asymmetry, altered skeletal proportions). If oceans continue to acidify as expected, ecosystems of the Atlantic dominated by this keystone species will be seriously threatened with major changes in many key benthic and pelagic ecosystems. Thus, it may be useful to monitor O. fragilis populations and initiate conservation if needed.
Resumo:
Our ability to project the impact of global change on marine ecosystem is limited by our poor understanding on how to predict species sensitivity. For example, the impact of ocean acidification is highly species-specific, even in closely related taxa. The aim of this study was to test the hypothesis that the tolerance range of a given species to decreased pH corresponds to their natural range of exposure. Larvae of the green sea urchin Strongylocentrotus droebachiensis were cultured from fertilization to metamorphic competence (29 days) under a wide range of pH (from pHT = 8.0/pCO2 ~ 480 ?atm to pHT = 6.5/pCO2 ~ 20 000 ?atm) covering present (from pHT 8.7 to 7.6), projected near-future variability (from pHT 8.3 to 7.2) and beyond. Decreasing pH impacted all tested parameters (mortality, symmetry, growth, morphometry and respiration). Development of normal, although showing morphological plasticity, swimming larvae was possible as low as pHT >= 7.0. Within that range, decreasing pH increased mortality and asymmetry and decreased body length (BL) growth rate. Larvae raised at lowered pH and with similar BL had shorter arms and a wider body. Relative to a given BL, respiration rates and stomach volume both increased with decreasing pH suggesting changes in energy budget. At the lowest pHs (pHT <= 6.5), all the tested parameters were strongly negatively affected and no larva survived past 13 days post fertilization. In conclusion, sea urchin larvae appeared to be highly plastic when exposed to decreased pH until a physiological tipping point at pHT = 7.0. However, this plasticity was associated with direct (increased mortality) and indirect (decreased growth) consequences for fitness.
Resumo:
A multicentennial and absolutely-dated shell-based chronology for the marine environment of the North Icelandic Shelf has been constructed using annual growth increments in the shell of the long-lived bivalve clam Arctica islandica. The region from which the shells were collected is close to the North Atlantic Polar Front and is highly sensitive to the varying influences of Atlantic and Arctic water masses. A strong common environmental signal is apparent in the increment widths, and although the correlations between the growth increment indices and regional sea surface temperatures are significant at the 95% confidence level, they are low (r ~ 0.2), indicating that a more complex combination of environmental forcings is driving growth. Remarkable longevities of individual animals are apparent in the increment-width series used in the chronology, with several animals having lifetimes in excess of 300 years and one, at 507 years, being the longest-lived non-colonial animal so far reported whose age at death can be accurately determined. The sample depth is at least three shells after AD 1175, and the time series has been extended back to AD 649 with a sample depth of one or two by the addition of two further series, thus providing a 1357-year archive of dated shell material. The statistical and spectral characteristics of the chronology are investigated by using two different methods of removing the age-related trend in shell growth. Comparison with other proxy archives from the same region reveals several similarities in variability on multidecadal timescales, particularly during the period surrounding the transition from the Medieval Climate Anomaly to the Little Ice Age.
Resumo:
Anthropogenic CO2 emissions are acidifying the world's oceans. A growing body of evidence is showing that ocean acidification impacts growth and developmental rates of marine invertebrates. Here we test the impact of elevated seawater pCO2 (129 Pa, 1271 µatm) on early development, larval metabolic and feeding rates in a marine model organism, the sea urchin Strongylocentrotus purpuratus. Growth and development was assessed by measuring total body length, body rod length, postoral rod length and posterolateral rod length. Comparing these parameters between treatments suggests that larvae suffer from a developmental delay (by ca. 8%) rather than from the previously postulated reductions in size at comparable developmental stages. Further, we found maximum increases in respiration rates of + 100 % under elevated pCO2, while body length corrected feeding rates did not differ between larvae from both treatments. Calculating scope for growth illustrates that larvae raised under high pCO2 spent an average of 39 to 45% of the available energy for somatic growth, while control larvae could allocate between 78 and 80% of the available energy into growth processes. Our results highlight the importance of defining a standard frame of reference when comparing a given parameter between treatments, as observed differences can be easily due to comparison of different larval ages with their specific set of biological characters.
Resumo:
Increased carbon dioxide (CO2) concentration in the atmosphere will change the balance of the components of carbonate chemistry and reduce the pH at the ocean surface. Here, we report the effects of increased CO2 concentration on the early development of the sea urchins Hemicentrotus pulcherrimus and Echinometra mathaei. We examined the fertilization, early cleavage, and pluteus larval stage to evaluate the impact of elevated CO2 concentration on fertilization rate, cleavage rate, developmental speed, and pluteus larval morphology. Furthermore, we compared the effects of CO2 and HCl at the same pH in an attempt to elucidate any differences between the two. We found that fertilization rate, cleavage rate, developmental speed, and pluteus larval size all tended to decrease with increasing CO2 concentration. Furthermore, CO2-seawater had a more severe effect than HCl-seawater on the fertilization rate. By contrast, the effects on cleavage rate, developmental speed, and pluteus larval morphology were similar for CO2- and HCl-seawater. Our results suggest that both decreased pH and altered carbonate chemistry affect the early development and life history of marine animals, implying that increased seawater CO2 concentration will seriously alter marine ecosystems. The effects of CO2 itself on marine organisms therefore requires further clarification.
Resumo:
Understanding the reasons for long-term population change in a species requires an evaluation of ecological variables that may account for the observed dynamics. In this study, long-term changes in indices of Smallmouth Bass condition and population levels were examined for eastern Lake Ontario and the Bay of Quinte. Smallmouth Bass are an extremely important recreational fish species native to Lake Ontario. They have experienced numerous changes in their environment through direct human impacts, climate change, predation, and habitat sharing with non-native species. Smallmouth Bass have experienced an increase in body length and weight likely due to a diet shift from crayfish to predominantly Round Gobies which has allowed them to increase their growth rate. According to existing assessment data however, this increase in body size has not been associated with an increase in abundance. Long-term data from gill net sampling shows that Smallmouth Bass populations have been declining since the late 1980s with no indication of recovery. This could be due to a variety of factors, but it is most likely due to a change in the selectivity of gill nets because of the change in body size as well as a habitat shift away from gill net sampling sites. Adjusting for gill net selectivity has revealed that sub-adult bass abundance is currently greater than it was historically, and that very large bass are likely not being retained within the gill nets that are currently used. The use of a long-term data set in this study has led to a much better understanding of Smallmouth Bass abundance and ecology.
Resumo:
ABSTRACT: The ability of Antarctic krill Euphausia superba Dana to withstand the overwintering period is critical to their success. Laboratory evidence suggests that krill may shrink in body length during this time in response to the low availability of food. Nevertheless, verification that krill can shrink in the natural environment is lacking because winter data are difficult to obtain. One of the few sources of winter krill population data is from commercial vessels. We examined length-frequency data of adult krill (>35 mm total body length) obtained from commercial vessels in the Scotia-Weddell region and compared our results with those obtained from a combination of science and commercial sampling operations carried out in this region at other times of the year. Our analyses revealed body-length shrinkage in adult females but not males during overwinter, based on both the tracking of modal size classes over seasons and sex-ratio patterns. Other explanatory factors, such as differential mortality, immigration and emigration, could not explain the observed differences. The same pattern was also observed at South Georgia and in the Western Antarctic Peninsula. Fitted seasonally modulated von Bertalanffy growth functions predicted a pattern of overwintering shrinkage in all body-length classes of females, but only stagnation in growth in males. This shrinkage most likely reflects morphometric changes resulting from the contraction of the ovaries and is not necessarily an outcome of winter hardship. The sex-dependent changes that we observed need to be incorporated into life cycle and population dynamic models of this species, particularly those used in managing the fishery. KEY WORDS: Southern Ocean · Population dynamics · Production · Life cycle · Fishery