Several researchers have studied turbulent structures, such as ejections, sweeps, and outwards and inwards interactions in flumes, where the streamwise velocity dominates over vertical and ...transversal velocities. However, this research presents an experimental study in which there are ejections associated with the interchange between surface and subsurface water, where the vertical velocity dominates over the streamwise component. The experiment is related to a surface alluvial stream that is polluted with fine sediment, which is percolated into the bed. The subsurface flow is modified by a lower permeability associated with the fine sediment and emerges to the surface current. Quasi-steady ejections are produced that drag fine sediment into the surface flow. Particle image velocimetry (PIV) measured the velocity field before and after the ejection. The velocity data were analyzed by scatter plots, power spectra, and wavelet analysis of turbulent fluctuations, finding changes in the distribution of turbulence interactions with and without the presence of fine deposits. The flow sediment ejection changes the patterns of turbulent structures and the distribution of the turbulence interactions that have been reported in open channels without subsurface flows.
Enrichment is the addition of nutrients to a food that does not contain them naturally, which is conducted in a mandatory manner and in order to solve a nutritional deficiency in the population. ...Enriched petipan are products that contain heme iron. The objective of this research was to evaluate the physical, chemical, mechanical and sensory characteristics of petipan produced with Andean grain flours and heme iron concentrate. A completely randomized design (CRD) with five experimental treatments was used with different levels of heme iron. The results show the direct influence of the heme concentration level on the chromatic, mechanical and textural characteristics of petipan. As the heme concentrate increases, its mechanical properties are considerably affected, with there being a correlation between the color intensity and a considerable reduction in its porosity. Samples without heme iron (T0) and 1% heme iron concentrate (T1) present the best mechanical and sensory characteristics; however, the incorporation of heme concentrate directly influences its nutritional, textural, and mainly chromatic components.
The purpose of the present paper was to examine the social validity of telepractice as a service delivery model for Spanish-speaking families of English learners. Quantitative survey methodology was ...employed to examine 79 caregivers' opinions regarding telepractice and to obtain background information about participants' home environments. Findings revealed that approximately 46% of the participant sample reported being interested in their children receiving services via telepractice. Caregivers reported limited familiarity with telepractice as an option, but were likely to express interest if their child had an identified speech or language disorder or if they were interested in increased access to Spanish language support for their children. In conclusion, although telepractice is not universally accepted among Spanish-speaking families, it appears to be a promising service delivery model. It is recommended that service providers offer thorough information and address common myths when considering telepractice as a service delivery model for families.
Abstract
Wildfires on the island of Tierra del Fuego in southern Argentina are not considered to have been a historic driver of forest dynamics. However, dramatic increases in the human population of ...the island over the last half-century have greatly increased fire ignition sources and thus the frequency of wildfires in the region. Lenga (Nothofagus pumilio (Poep. et Endl.) Krasser) forests support diverse ecosystem services by providing habitat for endemic flora and fauna and also represent a valuable timber resource for the forest industry of Tierra del Fuego. Evaluating the impact of forest fires on lenga regeneration is important not only because lenga is a native, slow-growing species that seems to lack adaptations that would allow it to recover rapidly after fire, but also because low tree species diversity on the island of Tierra del Fuego means lenga post-fire regeneration failure may lead to ecosystem state shifts. To determine how site characteristics and fire-impacted variables modulate post-fire regeneration densities and spatial patterns in lenga forests, we installed 192 plots (160 burned, 32 unburned) in which we measured site-characteristic (e.g. aspect, elevation) and fire-impacted (e.g. basal area, canopy cover) variables and tallied seedlings and saplings. Regeneration densities were significantly lower in burned than unburned plots. This was exacerbated with increasing distance from the unburned forest edge. Increasing distance to live trees that either survived fire or were outside the burned area negatively impacted regeneration as well. Time since fire negatively affected sapling, but not seedling counts. We concluded that lenga regeneration in the interior of burned areas is largely absent, delaying and potentially preventing forest recovery. These interior areas of burned lenga forests are unlikely to regenerate closed-canopy tree cover through passive restoration alone. Active restoration may be needed in these critical areas where live legacy trees are not present.
This paper shows the advances of an experimental study of the spill of copper concentrate into immobile gravel beds. The purposes of this research are to identify the dynamics of the copper ...concentrate as it spills in gravel bed rivers due to mining pipeline accidents, and to quantify loads of transport in suspension and bed infiltration experimentally. The sedimentation process is generated downstream of the spill, inducing the infiltration into the bed. We have found two types of infiltration: unimpeded static percolation, when the pore size is larger than the size of copper concentrate into the substrate, or bridging layer, when the size of copper concentrate is larger than the pores in the substrate. For large fluvial sediments,
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, the infiltration of the copper concentrate reaches a state of unimpeded static percolation. Moreover, when the size of the granular material is small,
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, the bridge layer avoid free infiltration of the copper concentrate. The maximum length of the bed on which we could make measurements is limited by the dimensions of the flume. About 50
%
by weight of the copper concentrate infiltrates in to the bed within a distance equal to 100 flow depths, downstream from the point where the spill was generated. Due to its high density, ultimately, the copper concentrate must completely infiltrate into the bed.
The aim of this preliminary study was to examine the feasibility of a rapid automatic naming (RAN) task for young Spanish–English speaking dual language learners (DLLs) and to examine the ...relationship between children’s performance on RAN and other standardized language and literacy assessments. A total of 275 Spanish–English speaking children in kindergarten and first grade attempted a RAN task and completed assessments of language and early literacy. Correlational analyses and quantile regression was conducted to examine relationships. Overall the RAN task was feasible for 74% (n = 203) of the DLLs; however, 42% of participants in kindergarten were unable to complete the task. There was a moderate positive correlation between RAN performance and standard scores in receptive vocabulary and letter identification, a small positive correlation with non-verbal intelligence, and no significant relationship with phonological awareness. There was a differential relation between RAN and English sentence imitation. The results support further consideration of RAN as a feasible and useful measure for young Spanish–English speaking DLLs.
The purpose of this study was to examine construct validity of methods of calculating lexical diversity in written narrative samples relative to children’s performance on a reading vocabulary ...measure. For 234 children in first to fifth grade, written narratives were examined and compared between grades for number of different words (NDW), total number of words (TNW), NDW in a truncated 50 word sample, and type token ratio (TTR). The relationship between lexical diversity in written narratives and a standardized reading vocabulary measure (Gates–McGinitie Reading Test–Fourth Edition GMRT-4) was analyzed by comparing correlations. Grade differences were observed in measures of lexical diversity and productivity. Lexical diversity showed a significant moderate correlation with the GMRT-4. NDW had a stronger relationship to GMRT-4 scores than TTR for participants in first and second grade. Considering length (TNW, NDW constrained to 50 words, or TTR) did not result in a stronger relationship with reading vocabulary. Following additional study establishing probe equivalence, NDW in written narratives may be an efficient, educationally relevant, marker of language maturity, and a good predictor of performance on a standardized reading vocabulary measure.
The aim of this randomized controlled trial was to determine the effects of 8-week exercise-intervention on cognition and related serum biochemical markers in nonagenarians. We also studied the ...effects of a 4-week training cessation ('detraining') period on our study variables. Participants were randomly allocated to a standard-care (control) or intervention (exercise) group n=20 (16 women)/group. The intervention focused on supervised, light-to-moderate-intensity aerobic and resistance exercises (mainly leg press), and included 3 weekly sessions. Cognitive status was determined by the mini-mental state examination and geriatric depression scale. We analysed proteins with reported relation with mechanisms behind cognition changes such as serum levels of angiotensin converting enzyme, amyloid-precursor protein, epidermal growth factor, brain-derived neural factor and tumor necrosis factor. No significant change (P>0.05) in any of the variables studied was found following the exercise intervention compared with the standard-care group. Similarly, no significant changes (P>0.05) were observed following the detraining period compared with the standard-care group. Overall changes after the exercise intervention in serum biomarkers were not associated with changes in functional capacity and cognitive measures. An 8-week exercise intervention focusing on resistance exercises neither benefits cognitive function nor affects the levels of the serum proteins analysed in nonagenarians.
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