1000 resultados para Cutting age
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[Abstract]
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At present, there is little fundamental guidance available to assist contractors in choosing when to schedule saw cuts on joints. To conduct pavement finishing and sawing activities effectively, however, contractors need to know when a concrete mixture is going to reach initial set, or when the sawing window will open. Previous research investigated the use of the ultrasonic pulse velocity (UPV) method to predict the saw-cutting window for early entry sawing. The results indicated that the method has the potential to provide effective guidance to contractors as to when to conduct early entry sawing. The aim of this project was to conduct similar work to observe the correlation between initial setting and conventional sawing time. Sixteen construction sites were visited in Minnesota and Missouri over a two-year period. At each site, initial set was determined using a p-wave propagation technique with a commercial device. Calorimetric data were collected using a commercial semi-adiabatic device at a majority of the sites. Concrete samples were collected in front of the paver and tested using both methods with equipment that was set up next to the pavement during paving. The data collected revealed that the UPV method looks promising for early entry and conventional sawing in the field, both early entry and conventional sawing times can be predicted for the range of mixtures tested.
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El objetivo principal de este estudio es conocer la concordancia entre informantes, padres y maestros,en cada una de las dimensiones o categorías diagnósticas del Early Childhood Inventory-4 (ECI-4).Además, se pretende analizar la influencia de la presencia de problemas de salud en los padres en ladescripción y valoración de la conducta de una muestra de 204 alumnos de preescolar (3 a 6 años) deperfiles socioeconómicos diferentes. Los resultados indican que los padres tienden a valorar con mayorseveridad los síntomas, observándose una mayor concordancia entre informantes en los relativos alos trastornos del desarrollo
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Aging is associated with an increased risk of depression in humans. To elucidate the underlying mechanisms of depression and its dependence on aging, here we study signs of depression in male SAMP8 mice. For this purpose, we used the forced swimming test (FST). The total floating time in the FST was greater in SAMP8 than in SAMR1 mice at 9 months of age; however, this difference was not observed in 12-month-old mice, when both strains are considered elderly. Of the two strains, only the SAMP8 animals responded to imipramine treatment. We also applied the dexamethasone suppression test (DST) and studied changes in the dopamine and serotonin (5-HT) uptake systems, the 5-HT2a/2c receptor density in the cortex, and levels of TPH2. The DST showed a significant difference between SAMR1 and SAMP8 mice at old age. SAMP8 exhibits an increase in 5-HT transporter density, with slight changes in 5-HT2a/2c receptor density. In conclusion, SAMP8 mice presented depression-like behavior that is dependent on senescence process, because it differs from SAMR1, senescence resistant strain.
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This study examined gross motor performance of 101 typically developing children between 3 and 5 years of age (48 boys, 53 girls, M age = 3.9 yr., SD = 0.5). All children performed 7 different gross motor tasks which were rated on a 5-point scale. Age and sex were assessed by an ordinal-logistic model, and odds ratios were calculated for each task using age and sex as covariates. For standing on one leg, walking on a beam, hopping on one leg, running, and taking stairs, statistically significant age differences were found, while for rising and jumping down, none were apparent. Mean motor performance did not differ between boys and girls on the tasks. The older the children were, the better they performed on the tasks.
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New geochronological data which clarify the timing of syn-orogenic magmatism and regional metamorphism in the Connemara Dalradian are presented. U-Pb zircon data on four intermediate to acid foliated magmatic rocks show important inherited components but the most concordant fractions demonstrate that major magmatism continued until 465 Ma whereas the earliest, basic magmatism has been dated previously at 490 Ma; a fine-grained, fabric-cutting granite contains discordant zircons which also appear to be 465 Ma old. Are magmatism in Connemara therefore spanned a period of at least 25 Ma. Recent U-Pb data on titanite from central Connemara which gave a peak metamorphic age of 478 Ma are supplemented by U-Pb data on titanite and monazite from metamorphic veins in the east of Connemara which indicate that low-P, high-T regional metamorphism ism continued there to 465 Ma, i.e. at least 10 Ma later than in the central region dated previously. New Rb-Sr data on muscovites from coarse-grained segregations in different structural settings range from 475 to 435 Ma; in part this range probably also reflects differences in age from west to east, with three ages close to 455 Ma from the eastern area, which is also the site of the lowest pressure metamorphism. Thermal modelling indicates that at any one locality the duration of metamorphism was probably as little as 1-2 Ma. The new dates emphasize the complexity in the spatial and temporal distribution of high-level regional metamorphism caused by magmatic activity. The relatively simple overall distribution of mineral-appearance isograds revealed by regional mapping masks the complexity of a prolonged but punctuated metamorphic history related to multiple intrusions, primarily in the southern part of Connemara. The later stages of magmatic activity followed progressive uplift and erosion after the onset of magmatism, and were localized in the eastern part of the region.
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Collembolan communities in conifer plantations (Japanese cedar, Cryptomeria japonica) and secondary deciduous broad-leaved forests of varying ages were investigated to determine the extent to which forest conversion (broad-leaved to coniferous) affects the species richness and assemblage composition of Collembola in central Japan. Density and total species richness of Collembola not differed between the broad-leaved and cedar forests except immediately after clear-cutting. The amount of forest-floor organic matter was larger in cedar forests and positively correlated with the species richness of detritus feeders. Species richness of fungal feeders and sucking feeders positively correlated with the species richness of forest-floor plants. There was difference in collembolan species composition between the forest types. The age of the forests seemed to have only small importance for the collembolan community, except during the first four years after clear-cutting. The conversion to artificial cedar stands has not reduced the abundance or species richness of collembolan communities, but has affected community composition. Differences in species composition may be related to the ground floras.
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The representation of age groups is becoming an increasingly discussed topic in Swiss politics. In this study, we explore inequalities in the descriptive and substantive representation of various age groups and find that despite important disparities in descriptive representation, the policy preferences of various age groups are relatively equally represented in the lower house of the Swiss parliament. Our analysis thus suggests that even if it is gaining visibility, the age cleavage is not central for parliamentary representation in Switzerland.
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Personality differences based on fine motor precision performance were studied in early stage Parkinson's patients and an age-matched control group under two different test conditions: proprioceptive + visual information and proprioceptive information alone. A comparative data analysis for deviations of three measured movement types (transversal, frontal and sagittal) was done for both hands (dominant and non-dominant) with relation to personality dimensions. There were found significant differences between the two groups in decision making dimension and emotionality. After splitting the data for gender subgroups, some significant differences were found for men but not for women. The differences in fine motor task performance varied, being better in some directions for the Parkinson"s patients and worse in others. The findings may suggest that medication has both positive and negative effects on motor performance and provoke personality changes, being more pronounced in men.
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Many questions in evolutionary biology require an estimate of divergence times but, for groups with a sparse fossil record, such estimates rely heavily on molecular dating methods. The accuracy of these methods depends on both an adequate underlying model and the appropriate implementation of fossil evidence as calibration points. We explore the effect of these in Poaceae (grasses), a diverse plant lineage with a very limited fossil record, focusing particularly on dating the early divergences in the group. We show that molecular dating based on a data set of plastid markers is strongly dependent on the model assumptions. In particular, an acceleration of evolutionary rates at the base of Poaceae followed by a deceleration in the descendants strongly biases methods that assume an autocorrelation of rates. This problem can be circumvented by using markers that have lower rate variation, and we show that phylogenetic markers extracted from complete nuclear genomes can be a useful complement to the more commonly used plastid markers. However, estimates of divergence times remain strongly affected by different implementations of fossil calibration points. Analyses calibrated with only macrofossils lead to estimates for the age of core Poaceae ∼51-55 Ma, but the inclusion of microfossil evidence pushes this age to 74-82 Ma and leads to lower estimated evolutionary rates in grasses. These results emphasize the importance of considering markers from multiple genomes and alternative fossil placements when addressing evolutionary issues that depend on ages estimated for important groups.
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[Abstract]
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Aging is associated with an increased risk of depression in humans. To elucidate the underlying mechanisms of depression and its dependence on aging, here we study signs of depression in male SAMP8 mice. For this purpose, we used the forced swimming test (FST). The total floating time in the FST was greater in SAMP8 than in SAMR1 mice at 9 months of age; however, this difference was not observed in 12-month-old mice, when both strains are considered elderly. Of the two strains, only the SAMP8 animals responded to imipramine treatment. We also applied the dexamethasone suppression test (DST) and studied changes in the dopamine and serotonin (5-HT) uptake systems, the 5-HT2a/2c receptor density in the cortex, and levels of TPH2. The DST showed a significant difference between SAMR1 and SAMP8 mice at old age. SAMP8 exhibits an increase in 5-HT transporter density, with slight changes in 5-HT2a/2c receptor density. In conclusion, SAMP8 mice presented depression-like behavior that is dependent on senescence process, because it differs from SAMR1, senescence resistant strain.