829 resultados para Early Age Concrete
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The Developmental Origins of Health and Disease Hypothesis proposes that adverse health outcomes in adult life are in part programmed during fetal life and infancy. This means that e.g. restricted nutrition during pregnancy programmes the offspring to store fat more effectively, to develop faster and to reach puberty earlier. These adaptations are beneficial in terms of short term survival. However, in developed countries these adaptations often lead to an increased risk of obesity and metabolic disturbances in later life, due to a mismatch between the prenatal and postnatal environment. This thesis aimed to study the role of early growth in people who are obese as adults, but metabolically healthy as well as in those who are normal in weight but metabolically obese. Other study aims were to assess whether physical activity and cardiorespiratory fitness are programmed early in life. The role of socioeconomic status in the development of obesity from a life course setting was also studied. These studies included 2003 men and women born in Helsinki between 1934 and 1944 with detailed information of their prenatal and childhood growth as well as living conditions. They participated in the detailed clinical examination during the years 2001-2004. A sub-group of the subjects participated in the UKK Institute 2-kilometre walk test. Metabolic syndrome was defined according to the 2005 criteria of the International Diabetes Federation. Among the obese men and women 20 % were metabolically healthy. Those with metabolic syndrome did not differ in birth size compared to the healthy ones, but by two years of age, they were lighter and thinner, and remained so up to 11 years. The period when changes in BMIs were predictive of the metabolic syndrome was from birth to 7 years. Of the normal weight individuals 17 % were metabolically obese. Again, there were no differences in birth size. However, by the age 7 years, those men who later developed metabolic syndrome were thinner. Gains in BMI during the first two years of life were protective of the syndrome. Children who were heavier, and especially taller, were more physically active, exercised with higher intensity and had higher cardiorespiratory fitness in their adult life than those who were shorter and thinner as children. Lower educational attainment and lower adult social class were associated with obesity in both men and women. Childhood social class was inversely associated with body mass index only in men while lower household income was associated with higher BMI in women. These results support the role of early life factors in the development of metabolic syndrome and adult life style. Early detection of risk factors predisposing to these conditions is highly relevant from a public health point of view.
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Fly ash and silica fume are two pozzolans that have been widely used for improved concrete strength and durability. Silica fume displays a greater pozzolanic reactivity than fly ash primarily due to its finer particle size. The reactivity of fly ash can be improved by reducing its particle size distribution. This paper discusses the fresh and hardened properties of concrete made with an ultra-fine fly ash (UFFA) produced by air classification. Durability testing for chloride diffusivity, rapid chloride permeability, alkali-silica reaction (ASR), and sulfate attack was also conducted It was found that at a given workability and water content, concrete containing UFFA could be produced with only 50% of the high-range water-reducer dosage required for comparable silica fume concrete. Similar early strengths and durability measures as silica fume concrete were observed when a slightly higher dosage of UFFA was used with a small reduction (10%) in water content.
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This article reports the acoustic emission (AE) study of precursory micro-cracking activity and fracture behaviour of quasi-brittle materials such as concrete and cement mortar. In the present study, notched three-point bend specimens (TPB) were tested under crack mouth opening displacement (CMOD) control at a rate of 0.0004 mm/sec and the accompanying AE were recorded using a 8 channel AE monitoring system. The various AE statistical parameters including AE event rate , AE energy release rate , amplitude distribution for computing the AE based b-value, cumulative energy (I E) pound and ring down count (RDC) were used for the analysis. The results show that the micro-cracks initiated and grew at an early stage in mortar in the pre peak regime. While in the case of concrete, the micro-crack growth occurred during the peak load regime. However, both concrete and mortar showed three distinct stages of micro-cracking activity, namely initiation, stable growth and nucleation prior to the final failure. The AE statistical behavior of each individual stage is dependent on the number and size distribution of micro-cracks. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the fracture process in quasi-brittle materials such as concrete & mortar and extend them for field applications.
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The evidence collected concerning the biocentric judgment that young children express when evaluating human actions on the environment leads some scholars to suggest that an essential understanding of the notion of living beings should appear earlier than previously believed. This research project aims to study that assumption. To this end, young children’s choice when they are put in situation of having to compare and choose the most negative option between environmentally harmful actions and the breaking of social conventions are examined. Afterwards, the results are categorized in relation to those obtained from the study of children’s grasp of the distinction between living beings and inanimate entities. The data is analysed according to the individuals’ age and overall, it suggests a lack of relationship between environmental judgment and the understanding of the concept of living beings. The final results are discussed in keeping with recent research in the field of moral development that underscores the role that unconscious emotional processing plays in the individual’s normative judgment.
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Since the launch of the JISC guide Innovative Practice with e-Learning (JISC, 2005), so much has changed. At that time, early adopters were exploring the potential of mobile and wireless learning. Since then, the increased availability of public and institutional wireless networks, the emergence of new and more powerful technologies and an increase in personal ownership of these technologies are changing the way we connect, communicate and collaborate. Emerging Practice in a Digital Age, one of a series of Effective Practice guides, draws on recent JISC reports and case studies and looks at how colleges and universities are continuing to embrace innovation and respond to changes in economic, social and technological circumstances in a fastchanging world.
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Arrowtooth flounder (Atheresthes stomias) has the highest biomass of any groundfish species in the Gulf of Alaska, is a voracious predator of age 1 walleye pollock (Theragra chalcogramma), and is a major component in the diet of Steller sea lions (Eumetopias jubatus). Owing to its ecological importance in the Gulf of Alaska and the limited information available on its reproduction, interest has intensified in describing its spawning and early life history. A study was undertaken in late January–February 2001–2003 in the Gulf of Alaska to obtain information on adult spawning location, depth distribution, and sexual maturity, and to obtain fertilized eggs for laboratory studies. Adults were found 200–600 m deep east of Kodiak Island over the outer continental shelf and upper slope, and southwest along the shelf break to the Shumagin Islands. Most ripe females (oocytes extruded with light pressure) were found at 400 m and most ripe males (milt extruded with light pressure) were found at depths ≥450 m. Eggs were fertilized and incubated in the laboratory at 3.0°, 4.5°, and 6.0°C. Eggs were reared to hatching, but larvae did not survive long enough to complete yolk absorption and develop pigment. Eggs were staged according to morphological hallmarks and incubation data were used to produce a stage duration table and a regression model to estimate egg age based on water temperature and developmental stage. Arrowtooth flounder eggs (1.58–1.98 mm in diameter) were collected in ichthyoplankton surveys along the continental shelf edge, primarily at depths ≥400 m. Early-stage eggs were found in tows that sampled to depths of ≥450 m. Larvae, which hatch between 3.9 and 4.8 mm standard length, increased in abundance with depth. Observations on arrowtooth flounder eggs and early-stage larvae were used to complete the description of the published partial developmental series.(PDF file contains 34 pages.)
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Adult steelhead (Oncorhynchus mykiss irideus) scales were analyzed from eight fall-run, two spring-run, and one winter-run stocks within the Klamath-Trinity River system, from 1981 through 1983, to provide basic information on age, growth, and life history. The higher degree of half-pounder occurrence of upper Klamath River steelhead stocks (86.7 to 100%) compared to Trinity River steelhead stocks (32.0 to 80.0%) was the major life history difference noted in scale analysis. Early life history was similar for all areas sampled with most juveniles (86.4%) remaining in freshwater during the first two years of life before migrating to sea. Repeat spawning ranged from 17.6 to 47.9% for fall-run, 40.0 to 63.6% for spring-run, and 31.1% for winter-run steelhead. Mean length of adults at first spawning was inversely related to percent half-pounder occurrence in each stock. Ages of returning spawners, back calculated lengths at various life stages, and growth information are presented. (PDF contains 22 pages)
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ENGLISH: Length-frequency samples of anchovetas were collected from January 1956 to March 1963. The findings for the most part corroborate those of previous studies in regard to the general pattern of age and growth. Recent tag returns demonstrate that some of the fish survive at least to the beginning of their fourth year of life. In 1961 and 1962 the fish were considerably larger than in any previous year for which data are available. The annual variation in the size of the young of the year is apparently related to the amount of upwelling and the density of the population during the early months of the year. SPANISH: De enero de 1956 a marzo de 1963 se recolectaron muestras de las frecuencias de longitud de las anchovetas. Las investigaciones, en su mayor parte, corraboran los resultados de los estudios anteriores referentes a los patrones generales de la edad y el crecimiento. Recobros recientes de mareas demuestran que algunos de los peces sobreviven por lo menos hasta el comienzo de su cuarto año de vida. En 1961 y 1962 los peces fueron considerablemente más grandes que en cualquiera de los años anteriores de los que se tienen datos disponibles. La variación anual en el tamaño de los peces jóvenes del año está aparentemente relacionada con el volumen del afloramiento y la densidad de la población durante los primeros meses del año. (PDF contains 51 pages)
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The EC (entorhinal cortex) is fundamental for cognitive and mnesic functions. Thus damage to this area appears as a key element in the progression of AD (Alzheimer's disease), resulting in memory deficits arising from neuronal and synaptic alterations as well as glial malfunction. In this paper, we have performed an in-depth analysis of astroglial morphology in the EC by measuring the surface and volume of the GFAP (glial fibrillary acidic protein) profiles in a triple transgenic mouse model of AD [3xTg-AD (triple transgenic mice of AD)]. We found significant reduction in both the surface and volume of GFAP-labelled profiles in 3xTg-AD animals from very early ages (1 month) when compared with non-Tg (non-transgenic) controls (48 and 54%, reduction respectively), which was sustained for up to 12 months (33 and 45% reduction respectively). The appearance of Lambda beta (amyloid beta-peptide) depositions at 12 months of age did not trigger astroglial hypertrophy; nor did it result in the close association of astrocytes with senile plaques. Our results suggest that the AD progressive cognitive deterioration can be associated with an early reduction of astrocytic arborization and shrinkage of the astroglial domain, which may affect synaptic connectivity within the EC and between the EC and other brain regions. In addition, the EC seems to be particularly vulnerable to AD pathology because of the absence of evident astrogliosis in response to A beta accumulation. Thus we can consider that targeting astroglial atrophy may represent a therapeutic strategy which might slow down the progression of AD.
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ENGLISH: Increments in otoliths (sagittae) were examined, using light and scanning electron microscopy, to determine ages and estimate growth rates of larval and early-juvenile black skipjack, Euthynnus lineatus. Larvae and juveniles were collected between 1987 and 1989 from coastal waters of Panama in the eastern Pacific Ocean. Results from a laboratory experiment indicated that immersion for 6 and 12 hours in a 200 mg/L solution of tetracycline hydrochloride adequately marks otoliths and that increments are formed daily in the sagittae of postflexion larvae and early juveniles. Further, survival rates of tetracycline-treated fish were not significantly different from those of control fish. Growth rates were derived from length-age relationships of 218 field-collected specimens ranging in size from 5.7 to 20.3 mm SL. A growth rate of 0.70 mm/d was estimated from the weighted regression of standard length on age for all specimens. This rate lies within the range reported for larvae and early juveniles of other species of subtropical and tropical scombrids. Growth rates of postflexion larvae and early juveniles were not significantly different between the rainy season in July-August 1988 and the dry, upwelling season in January-February 1989. Growth was, however, significantly more variable for older individuals in July-August than in January-February, and may correspond, in part, to seasonal patchiness of prey. The growth rates of the otoliths relative to fish length were also not significantly different between seasons; however, the otoliths were larger relative to the lengths of fish collected in the rainy season, which may reflect slower growth during earlier larval stages. SPANISH: Se examinaron incrementos en otolitos (ságitas), usando microscopia de luz y de barrido electrónico, a fin de determinar la edad y estimar las tasas de crecimiento de barriletes negros, Euthynnus lineatus, larvales y juveniles tempranos. Entre 1987 y 1989 se capturaron larvas y juveniles en las aguas costeras de Panamá en el Océano Pacífico oriental. Los resultados de un experimento de laboratorio indicaron que una inmersión de 6 a 12 horas de duración en una solución de 200 mg/L de hidrocloro de tetraciclina marca los otolitos adecuadamente y que los incrementos se forman a diario en las ságitas de larvas en postflexión y juveniles tempranos. Además, las tasas de supervivencia de los peces tratados con tetraciclina no fueron significativamente diferentes a aquellas de los peces de control. Se calcularon las tasas de crecimiento a partir de las relaciones de talla-edad de 218 especímenes de TE entre 5.7 y 20.3 mm capturados en el mar. Se estimó.una tasa de crecimiento de 0.70 mm/día a partir de la regresión ponderada de talla estándar sobre edad para todos los especímenes. Esta tasa cae dentro del rango reportado para larvas y juveniles tempranos de otras especies de escómbridos subtropicales y tropicales. Las tasas de crecimiento de larvas en postflexión y juveniles tempranos no fueron significativamente diferentes entre la temporada de lluvias en julio-agosto de 1988 y la temporada de sequía y afloramiento en enero-febrero de 1989. Sin emoargo, el crecimiento fue significativamente más variable para los individuos de mayor edad en julio-agosto que en enero-febrero, y quizás corresponda parcialmente a la irregularidad temporal de la abundancia de presas. Las tasas de crecimiento de los otolitos en relación a la talla de los peces tampoco fueron significativamente diferentes entre temporadas; sin embargo, los otolitos eran más grandes en relación a la talla en peces capturados en la temporada de lluvias, lo cual podría reflejar crecimiento más lento durante las etapas larvales más tempranas. (PDF contains 42 pages.)
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A maternidade na adolescência é um fenômeno que atinge cerca de 20% dos partos no Brasil. A importância deste tema no campo dos direitos articula-se à dupla condição de proteção conferida à estas mulheres: a de adolescente e a de mãe. O presente estudo apresenta os resultados de uma tese de doutorado com vistas à identificação das políticas sociais efetivamente acessadas por mulheres que foram mães na adolescência antes e após o parto. Buscamos verificar se os direitos sociais firmados na legislação brasileira foram disponibilizados a elas ao longo de sua vida. O campo de pesquisa compreendeu duas unidades públicas de saúde no município do Rio de Janeiro. Foi utilizada a metodologia qualitativa e a técnica empregada foi a saturação de informações, com sete mulheres entrevistadas após quatro anos do nascimento de seus filhos. A eleição desta idade buscou garantir um período distanciamento do início da vida da criança, verificando o impacto do nascimento desta na via da mulher de maneira mais isenta. A pesquisa foi aprovada pelo comitê de ética em pesquisa da prefeitura da cidade do Rio de Janeiro. Os resultados demonstram que que as mulheres que foram mães adolescentes atravessaram um cotidiano de pobreza, sobrecarga da figura materna, hierarquia de gênero e ausência de políticas públicas. Mesmo às que estavam em situação de risco, não foram proporcionadas políticas de apoio para a reversão do quadro.A conclusão que se chega é que as mães adolescentes são pouco atingidas por estas políticas públicas porque antes da gravidez estas adolescentes não eram vistas como ameaças à sociedade. Após a gravidez, passam pela rotulação do desperdício de oportunidades, e portanto, continuam sem a proteção da política pública, uma vez que do ponto de vista dos discursos da meritocracia individual presentes nas políticas do risco, não devem ser apoiadas em seus comportamentos tidos como promíscuos. Conclui-se ainda que a melhor estratégia de prevenção da maternidade adolescentes reside no oferecimento de oportunidades concretas de melhorias materias às famílias, de modo que as mulheres não necessitem tormar para si prematuramente as responsabilidades do mundo adulto e que possam ser estimuladas a incluir em seus planos futuros de uma inserção profissional mais qualificada. O estímulo à escolaridade materna (pelos benefícios que a mesma proporciona de melhor inserção no mercado de trabalho e de acesso a renda) é considerado um elemento fundamental neste processo, assim como os programas de valorização do envolvimento masculino nas questões de reprodução/cuidado infantil, programas de promoção de qualidade de vida e prevenção das violências. A tese termina reafirmando a base histórica do exercício dos direitos e a necessidade da explicitação da natureza política do enfrentamento da questão social.
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Reinforced concrete structures are introduced in Spain mainly by French influence. This happens in the late nineteenth century, following the scheme operating through proprietary systems prevailing in Europe. Systems initially have poor scientific support reaching, even early twentieth century, an impediment to the development of concrete structures, due to the lack of knowledge shown, as well as due to a series of accidents. Therefore, from the end of the first decade of the past century are enacted a series of regulations in many countries, that will change the design and calculation of reinforced concrete structure. The knowledge of the environment of the patent systems, its beginnings and the circumstances of their application allow us to understand the constraints of the early concrete structures, as presented in the Bilbao wine store (1906).
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Settled juvenile blue rockfish (Sebastes mystinus) were collected from two kelp beds approximately 335 km apart off Mendocino in northern California and Monterey in central California. A total of 112 rockfish were collected from both sites over 5 years (1993, 1994, 2001, 2002, and 2003). Total age, settlement date, age at settlement, and birth date were determined from otolith microstructure. Fish off Mendocino settled mostly in June and fish off Monterey settled mostly in May (average difference in settlement=23 days). Although the difference in the timing of settlement followed this same pattern for both areas over the five years, settlement occurred later in 2002 and 2003 than in the prior years of sampling. The difference in the timing of settlement was due primarily to differences in birth dates for the two areas. The time of settlement was positively related to upwelling and negatively related to sea level anomaly for most of the months before settlement. Knowledge of the timing of settlement has implications for design and placement of marine protected areas because protection of nursery grounds is frequently a major objective of these protected areas. The timing of settlement is also an important consideration in the planning of surveys of early recruits because mistimed surveys (caused by latitudinal differences in the timing of settlement) could produce biased estimates.
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Age, growth, and reproductive data were obtained from dolphinfish (Coryphaena hippurus, size range: 89 to 1451 mm fork length [FL]) collected between May 2002 and May 2004 off North Carolina. Annual increments from scales (n=541) and daily increments from sagittal otoliths (n=107) were examined; estimated von Bertalanffy parameters were L∞ (asymptotic length)=1299 mm FL and k (growth coefficient)=1.08/yr. Daily growth increments reduced much of the residual error in length-at-age estimates for age-0 dolphinfish; the estimated average growth rate was 3.78 mm/day during the first six months. Size at 50% maturity was slightly smaller for female (460 mm FL) than male (475 mm FL) dolphinfish. Based on monthly length-adjusted gonad weights, peak spawning occurs from April through July off North Carolina; back-calculated hatching dates from age-0 dolphinfish and prior reproductive studies on the east coast of Florida indicate that dolphinfish spawning occurs year round off the U.S. east coast and highest levels range from January through June. No major changes in length-at-age or size-at-maturity have occurred since the early 1960s, even after substantial increases in fishery landings.