Comparing In-View to Out-of-View Stimulus Arrangements When Teaching Receptive Labels for Children Diagnosed With Autism Spectrum Disorder.

One common best practice recommendation for teaching receptive labels to individuals diagnosed with autism spectrum disorder is for the stimulus array to be arranged outside of the view of the learner. Another strategy that may have benefits would be to arrange the stimuli in view of the learner. The purpose of this study was to compare the relative effectiveness and efficiency of arranging the stimulus array in view versus out of view of the learner when teaching receptive labels to three children diagnosed with autism spectrum disorder. The results of an adapted alternating-treatments design demonstrated that both conditions were effective, and all participants reached the mastery criterion on all training sets. However, the in-view condition was more, or equally, efficient with respect to sessions to mastery when compared to the out-of-view condition. The results are discussed with respect to clinical and research implications for best practice recommendations related to teaching receptive language.

Pattern and scale: evaluating generalities in crab distributions and marsh dynamics from small plots to a national scale.

The generality of ecological patterns depends inextricably on the scale at which they are examined. We investigated patterns of crab distribution and the relationship between crabs and vegetation in salt marshes at multiple scales. By using consistent monitoring protocols across 15 U.S. National Estuarine Research Reserves, we were able to synthesize patterns from the scale of quadrats to the entire marsh landscape to regional and national scales. Some generalities emerged across marshes from our overall models, and these are useful for informing broad coastal management policy. We found that crab burrow distribution within a marsh could be predicted by marsh elevation, distance to creek and soil compressibility. While these physical factors also affected marsh vegetation cover, we did not find a strong or consistent overall effect of crabs at a broad scale in our multivariate model, though regressions conducted separately for each site revealed that crab burrows were negatively correlated with vegetation cover at 4 out of 15 sites. This contrasts with recent smaller-scale studies and meta-analyses synthesizing such studies that detected strong negative effects of crabs on marshes, likely because we sampled across the entire marsh landscape, while targeted studies are typically limited to low-lying areas near creeks, where crab burrow densities are highest. Our results suggest that sea-level rise generally poses a bigger threat to marshes than crabs, but there will likely be interactions between these physical and biological factors. Beyond these generalities across marshes, we detected some regional differences in crab community composition, richness, and abundance. However, we found striking differences among sites within regions, and within sites, in terms of crab abundance and relationships to marsh integrity. Although generalities are broadly useful, our findings indicate that local managers cannot rely on data from other nearby systems, but rather need local information for developing salt marsh management strategies.

Osteoblast extracellular Ca2+ -sensing receptor regulates bone development, mineralization, and turnover.

The extracellular Ca(2+) -sensing receptor (CaR), a G protein-coupled receptor responsible for maintenance of calcium homeostasis, is implicated in regulation of skeletal metabolism. To discern the role of the osteoblast CaR in regulation of bone development and remodeling, we generated mice in which the CaR is excised in a broad population of osteoblasts expressing the 3.6-kb a(1) (I) collagen promoter. Conditional knockouts had abnormal skeletal histology at birth and developed progressively reduced mineralization secondary to retarded osteoblast differentiation, evident by significantly reduced numbers of osteoblasts and decreased expression of collagen I, osteocalcin, and sclerostin mRNAs. Elevated expression of ankylosis protein, ectonucleotide pyrophosphatase/phosphodiesterase 1, and osteopontin mRNAs in the conditional knockout indicate altered regulation of genes important in mineralization. Knockout of the osteoblast CaR also resulted in increased expression of the receptor activator of NF-κB ligand (RANKL), the major stimulator of osteoclast differentiation and function, consistent with elevated osteoclast numbers in vivo. Osteoblasts from the conditional knockouts exhibited delayed differentiation, reduced mineralizing capacity, altered expression of regulators of mineralization, and increased ability to promote osteoclastogenesis in coculture experiments. We conclude that CaR signaling in a broad population of osteoblasts is essential for bone development and remodeling and plays an important role in the regulation of differentiation and expression of regulators of bone resorption and mineralization.

Constitutive activity of the osteoblast Ca2+-sensing receptor promotes loss of cancellous bone.

Changes in extracellular [Ca2+] modulate the function of bone cells in vitro via the extracellular Ca2+-sensing receptor (CaR). Within bone microenvironments, resorption increases extracellular [Ca2+] locally. To determine whether enhanced CaR signaling could modulate remodeling and thereby bone mass in vivo, we generated transgenic mice with a constitutively active mutant CaR (Act-CaR) targeted to their mature osteoblasts by the 3.5 kb osteocalcin promoter. Longitudinal microcomputed tomography of cancellous bone revealed reduced bone volume and density, accompanied by a diminished trabecular network, in the Act-CaR mice. The bone loss was secondary to an increased number and activity of osteoclasts, demonstrated by histomorphometry of secondary spongiosa. Histomorphometry, conversely, indicates that bone formation rates were unchanged in the transgenic mice. Constitutive signaling of the CaR in mature osteoblasts resulted in increased expression of RANK-L (receptor activator of nuclear factor-kappaB ligand), the major stimulator of osteoclast differentiation and activation, which is the likely underlying mechanism for the bone loss. The phenotype of Act-CaR mice is not attributable to systemic changes in serum [Ca2+] or PTH levels. We provide the first in vivo evidence that increased signaling by the CaR in mature osteoblasts can enhance bone resorption and further propose that fluctuations in the [Ca2+] within the bone microenvironment may modulate remodeling via the CaR.