944 research outputs found
On the Antiquity of Trisomy 21: Moving Towards a Quantitative Diagnosis of Down Syndrome in Historic Material Culture
Down syndrome was first medically described as a separate condition from other forms of cognitive impairment in 1866. Because it took so long for Down syndrome to be recognized as a clinical entity deserving its own status, several investigators have questioned whether or not Down syndrome was ever recognized before 1866. Few cases of ancient skeletal remains have been documented to have Down syndrome-like characteristics. However, several forms of material culture may depict this condition. Within this paper the history of our understanding of Down syndrome is discussed. Both skeletal remains and different forms of material culture that may depict Down syndrome are described, and where relevant, debates within the literature about how likely such qualitative diagnoses are to be correct are also discussed. Suggestions are then made for ways in which a quantitative diagnosis can be made to either strengthen or weaken qualitative arguments for or against the diagnosis of Down syndrome in different forms of historic material culture
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Opening Pandora's Box: Studying the Accuracy of Managers' Perceptions
Both researchers and managers depend on the accuracy of managers' perceptions. Yet, few studies compare subjective with
"objective" data, perhaps because it is very difficult to do well. These difficulties also muddy interpretations of results. On
one hand, studies suggest that managers' perceptions may be very inaccurate. On the other hand, the observed errors in
managerial perceptions may arise from research methods instead of managers.
Because perceptual data are so significant for both researchers and managers, researchers need to understand both the
potential contaminants of perceptual research and the determinants of perceptual errors and biases. This article reviews
studies of the accuracies of managers' perceptions, points out hazards in such research, and suggests various ways to
improve studies of perceptions. The suggestions encompass improvements in gathering more valid subjective data, locating
more appropriate "objective" data, finding appropriate respondents, and using statistical methods that provide accurate and
reliable estimates with small samples.Information Systems Working Papers Serie
Facial Soft-Tissue Asymmetry in 3D Cone Beam Computed Tomography Images of Children with Surgically Corrected Unilateral Clefts
Cleft lip with or without cleft palate (CL/P) is a relatively common craniofacial malformation involving bony and soft-tissue disruptions of the nasolabial and dentoalveolar regions. The combination of CL/P and subsequent craniofacial surgeries to close the cleft and improve appearance of the cutaneous upper lip and nose can cause scarring and muscle pull, possibly resulting in soft-tissue depth asymmetries across the face. We tested the hypothesis that tissue depths in children with unilateral CL/P exhibit differences in symmetry across the sides of the face. Twenty-eight tissue depths were measured on cone-beam computed tomography images of children with unilateral CL/P (n = 55), aged 7 to 17 years, using Dolphin software (version 11.5). Significant differences in tissue depth symmetry were found around the cutaneous upper lip and nose in patients with unilateral CL/P
Morphological Integration of Soft-Tissue Facial Morphology in Down Syndrome and Siblings
Down syndrome (DS), resulting from trisomy of chromosome 21, is the most common live-born human aneuploidy. The phenotypic expression of trisomy 21 produces variable, though characteristic, facial morphology. Although certain facial features have been documented quantitatively and qualitatively as characteristic of DS (e.g., epicanthic folds, macroglossia, and hypertelorism), all of these traits occur in other craniofacial conditions with an underlying genetic cause. We hypothesize that the typical DS face is integrated differently than the face of non-DS siblings, and that the pattern of morphological integration unique to individuals with DS will yield information about underlying developmental associations between facial regions. We statistically compared morphological integration patterns of immature DS faces (N = 53) with those of non-DS siblings (N = 54), aged 6–12 years using 31 distances estimated from 3D coordinate data representing 17 anthropometric landmarks recorded on 3D digital photographic images. Facial features are affected differentially in DS, as evidenced by statistically significant differences in integration both within and between facial regions. Our results suggest a differential affect of trisomy on facial prominences during craniofacial development
Estimating Travel Cost Model: Spatial Approach
travel cost model, spatial analysis, Environmental Economics and Policy,
A Three-Dimensional Analysis of Maxillary Sinus Congestion in Unilateral Cleft Lip and Palate
Cleft lip and palate (CLP) perturbs osseous and soft-tissue development of the nasolabial regions, often resulting in chronic maxillary sinusitis and mucosal thickening (MT) of the maxillary sinus. This preliminary study quantifies maxillary sinus MT in children with surgically repaired unilateral CLP. We hypothesize that maxillary sinus MT is increased in children with CLP relative to controls. We define "MT" as the difference between the entire maxillary sinus volume and airspace volume. Cone beam computed tomography (CBCT) images of 8-14 yr. old age- and sex-matched unilateral CLP patients (n = 10) and controls (n = 10) were obtained (IRB approval # 1210009813). Both maxillary sinus and airspace surface areas (SAs) were measured on each individual CBCT slice in coronal view. SA measurements were summed and multiplied by voxel size (0.4mm) to obtain a volume. Paired t-tests determined whether maxillary sinus volume, air volume, MT (i.e. maxillary sinus volume – airspace volume), and percentage of MT (i.e. MT/maxillary size x 100) differed. A p-value of ≤ 0.05 was considered significant. Intra-class correlation assessed reliability and was high (0.99). Significant differences were found for several measurements: Maxillary airspace (non-cleft side vs. right side control p-value = 0.002; cleft-side vs. left side control p-value = 0.004), MT (cleft-side vs. left side p-value = 0.009), and percentage of MT (non-cleft side vs. right side control p-value = 0.002, cleft-side vs. left side control p-value = 0.002). Maxillary airspace was decreased by 30% (non-cleft side) and by 33% (cleft side). Percentage of average MT was 40% (non-cleft side) and 42% (cleft side) of CLP patients, but only 9% (left and right side) in controls. Surgically repaired CLP patients exhibit decreased maxillary airspace and increased MT relative to controls. CLP deformities are associated with MT. 3D imaging is useful for quantitatively evaluating MT of the maxillary sinus
The auxiliary use of LANDSAT data in estimating crop acreages: Results of the 1975 Illinois crop-acreage experiment
The author has identified the following significant results. It was found that classifier performance was influenced by a number of temporal, methodological, and geographical factors. Best results were obtained when corn was tasselled and near the dough stage of development. Dates earlier or later in the growing season produced poor results. Atmospheric effects on results cannot be independently measured or completely separated from the effects due to the maturity stage of the crops. Poor classifier performance was observed in areas where considerable spectral confusion was present
3D Assessment of Nasopharyngeal and Craniofacial Phenotypes in Ts65Dn Down Syndrome Mice Treated with a Dyrk1a Inhibitor
Background: Down syndrome (DS) originates from having three copies of chromosome 21 (i.e. Trisomy 21). DS is associated with many detrimental phenotypes including intellectual disabilities, heart defects, abnormal craniofacial development, and obstructive sleep apnea, which develops from restricted nasopharyngeal airways and an underdeveloped mandible. Ts65Dn mice are trisomic for about half of the orthologs on human chromosome 21 and display many phenotypes associated with DS including craniofacial abnormalities. Dyrk1a is found in three copies in Ts65Dn mice and individuals with DS, and thought to be a root cause of the craniofacial phenotypes. Epigallocatechin 3-gallate (EGCG) is a green tea polyphenol and inhibitor of Dyrk1a activity.
Purpose: We hypothesize that decreased Dyrk1a activity in Ts65Dn mice will ameliorate craniofacial dysmorphology.
Methods: To test our hypothesis we compared Ts65Dn mice with two or three copies of Dyrk1a and compared Ts65Dn mice with and without prenatal EGCG treatment. EGCG treated mothers were fed 200mg/kg EGCG on gestational day 7. Six week old mice were sacrificed and their heads imaged using micro-computed tomography (ÎĽCT). From ÎĽCT images, we measured nasopharyngeal airway volume and anatomical landmarks (n = 54) from the facial skeleton, cranial vault, cranial base, and mandible. Mean nasopharyngeal airway volumes were graphically compared, and a landmark-based multivariate geometric morphometric approach known as Euclidean Distance Matrix Analysis (EDMA) was carried out to assess local differences in craniofacial morphology between trisomic mouse samples.
Results: Our preliminary results indicate that EGCG treatment and reduced Dyrk1a copy number increases mean nasopharyngeal airway volume in Ts65Dn mice. Craniofacial morphometric differences were found among all samples. EGCG treatment increased portions of the mandible and decreased portions of the cranial vault and cranial base.
Conclusion: Preliminary analyses suggest that both EGCG treatment and reduced Dyrk1a copy number affect craniofacial morphology.Three Dimensional Imaging of the Craniofacial Complex Center (3D ICCC)--IUPUI Signature Center Initiative
Opening Pandora's Box: Studying the Accuracy of Managers' Perceptions
Both researchers and managers depend on the accuracy of managers' perceptions. Yet, few studies compare subjective with
"objective" data, perhaps because it is very difficult to do well. These difficulties also muddy interpretations of results. On
one hand, studies suggest that managers' perceptions may be very inaccurate. On the other hand, the observed errors in
managerial perceptions may arise from research methods instead of managers.
Because perceptual data are so significant for both researchers and managers, researchers need to understand both the
potential contaminants of perceptual research and the determinants of perceptual errors and biases. This article reviews
studies of the accuracies of managers' perceptions, points out hazards in such research, and suggests various ways to
improve studies of perceptions. The suggestions encompass improvements in gathering more valid subjective data, locating
more appropriate "objective" data, finding appropriate respondents, and using statistical methods that provide accurate and
reliable estimates with small samples.Information Systems Working Papers Serie
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