Developmental dynamics between reading and math in elementary school.

Reading and math attainment develop during elementary grades. Questions remain, though, about the co-developmental nature of the relation between reading and math. This study examined dynamic, longitudinal pathways between reading and math in first through fourth grades. Participants of the study were 554 academically at-risk children (Mage at the first assessment point = 6.57 years; SD = 0.38) from Texas Project Achieve. Children were assessed utilizing the Woodcock-Johnson-III reading and math measures. Results from dynamic bivariate latent change score models indicated unidirectional longitudinal coupling effects from reading to math. Specifically, average and high levels of reading performance were associated with subsequent gains in math growth, in particular for below average performing children in math. In contrast, low levels of reading performance had negligible or no amplifying influences on change in math growth. The nature of the dynamics was replicated even when controlling for nonverbal cognitive abilities. Results demonstrated that good reading skills pave the way for children to develop their math skills. Such findings underscore the importance of considering reading performance in treating math difficulties.

Ten-year risk of complication and mortality after total hip arthroplasty in morbidly obese patients: a population study

Background: The relationship between morbid obesity and long-term patient outcomes after primary total hip arthroplasty (THA) has been understudied. The purpose of this study was to determine the association between morbid obesity and 10-year complications (revision surgery, reoperation, dislocation) and mortality in patients undergoing primary THA. Methods: We conducted a population-based cohort study of patients aged 45­74 years who underwent primary THA for osteoarthritis between 2002 and 2007 using Ontario administrative health care databases. Patients were followed for 10 years. We estimated risk ratios (RRs) of mortality, reoperation, revision and dislocation in patients with body mass index (BMI) greater than 45 kg/m2 (morbidly obese patients) compared with patients with a BMI of 45 kg/m2 or less (nonmorbidly obese patients). Results: There were 22 251 patients in the study cohort, of whom 726 (3.3%) were morbidly obese. Morbid obesity was associated with higher 10-year risk of death (RR 1.38, 95% confidence interval [CI] 1.18­1.62). Risks of revision (RR 1.43, 95% CI 0.96­2.13) and dislocation (RR 2.38, 95% CI 1.38­4.10) were higher in morbidly obese men than in nonmorbidly obese men; there were no associations between obesity and revision or dislocation in women. Risk of reoperation was higher in morbidly obese women than in nonmorbidly obese women (RR 1.59, 95% CI 1.05­2.40); there was no association between obesity and reoperation in men. Conclusion: Morbidly obese patients undergoing primary THA are at higher risk of long-term mortality and complications. There were differences in complication risk by sex. The results of this study should inform perioperative counselling of patients considering THA.

Contexte: Le lien entre l'obésité morbide et les issues à long terme des patients ayant subi une arthroplastie totale primaire de la hanche (ATH) est sous-étudié. Cette étude visait à caractériser l'association entre l'obésité morbide et les complications (chirurgie de révision, réintervention, dislocation) et la mortalité sur 10 ans chez les patients ayant subi une ATH. Méthodes: Nous avons mené une étude de cohorte basée sur la population auprès de patients de 45 à 74 ans atteints d'arthrose ayant subi une ATH primaire entre 2002 et 2007 en utilisant les bases de données administratives en santé de l'Ontario. Les patients ont été suivis pour une période de 10 ans. Nous avons estimé des rapports de risque (RR) pour la mortalité, la réintervention, la chirurgie de révision et la dislocation chez les patients ayant un indice de masse corporelle (IMC) de plus de 45 kg/m2 (obésité morbide) en comparaison avec les patients ayant un IMC de 45 kg/m2 ou moins. Résultats: L'étude de cohorte comptait 22 251 patients, dont 726 (3,3 %) étaient atteints d'obésité morbide. L'obésité morbide a été associée à un risque de mortalité sur 10 ans accru (RR 1,38; intervalle de confiance [IC] de 95 % 1,18­1,62). Le risque de chirurgie de révision (RR 1,43; IC de 95 % 0,96­2,13) et de dislocation (RR 2,38; IC de 95 % 1,38­4,10) était plus élevé chez les hommes atteints d'obésité morbide que chez les autres hommes; aucune association n'a été observée entre l'obésité et la chirurgie de révision ou la dislocation chez les femmes. Par contre, le risque de réintervention était accru chez les femmes atteintes d'obésité morbide (RR 1,59; IC de 95 % 1,05­2,40), mais aucune association n'a été établie entre l'obésité et la réintervention chez les hommes. Conclusion: Les patients atteints d'obésité morbide qui subissent une ATH primaire courent un risque plus élevé de complications et de mortalité à long terme. Des différences ont été observées dans les risques de complications selon le sexe. Les résultats de cette étude devraient guider l'offre de conseils aux patients qui envisagent l'ATH.

Using Cholesky Decomposition to Explore Individual Differences in Longitudinal Relations between Reading Skills.

The Cholesky decomposition method is the gold standard used in the field of behavioral genetics. The method is popular because it is easy to program and solve. Using this method, researchers can explore individual differences in longitudinal relations of different variables across multiple time points. The method allows investigators to decompose variance into (1) unique genetic, shared and non-shared environmental effects that arise at specific time points as well as (2) overlapping genetic, shared and non-shared environmental effects that carry over from one time point to another. However, the method does not identify the mechanisms or origins underlying these effects. The current report focuses on application of the Cholesky decomposition method in the field of educational psychology. Specifically, it discusses individual differences in longitudinal relations between kindergarten letter knowledge, kindergarten phonological awareness, first grade word-level reading skills, and seventh grade reading comprehension.

Ten-Year Mortality and Revision After Total Knee Arthroplasty in Morbidly Obese Patients.

BACKGROUND: Although morbid obesity has been associated with early surgical complications after total knee arthroplasty (TKA), evidence of long-term outcomes is limited. We conducted a population-based study to determine the association between morbid obesity and 10-year survival and revision surgery in patients undergoing primary TKA. METHODS: A cohort study of 9817 patients aged 18-60 years treated with primary TKA from April 1, 2002 to March 31, 2007 was conducted using Ontario administrative health-care databases of universal health-care coverage. Patients were followed up for 10 years after TKA. Risk ratios (RRs) of mortality and TKA revision surgery in patients with body mass index > 45 kg/m2 (morbidly obese patients) compared with body mass index ≤45 kg/m2 (nonmorbidly obese) were estimated adjusting for age, sex, socioeconomic status, and comorbidities. RESULTS: About 10.2% (1001) of the cohort was morbidly obese. Morbidly obese patients were more likely to be female than nonmorbidly obese patients (82.5% vs 63.7%, P < .001) but otherwise similar in characteristics. Morbidly obese patients had higher 10-year risk of death than nonmorbidly obese patients (adjusted RR 1.50, 95% confidence interval 1.22-1.85). About 8.5% (832) of the patients had at least 1 revision procedure in the 10 years after TKA; revision rates did not differ by obesity (adjusted RR 1.09, 95% confidence interval 0.88-1.34). CONCLUSION: Morbidly obese patients ≤60 years had a 50% higher 10-year risk of death but no difference in the risk of revision surgery. Results of this population-based study inform evidence-based perioperative counseling of morbidly obese patients considering TKA.

Computed tomography as ground truth for stereo vision measurements of skin.

Although dysesthesia is a common surgical complication, there is no accepted method for quantitatively tracking its progression. To address this, two types of computer vision technologies were tested in a total of four configurations. Surface regions on plastic models of limbs were delineated with colored tape, imaged, and compared with computed tomography scans. The most accurate system used visually projected texture captured by a binocular stereo camera, capable of measuring areas to within 3.4% of the ground-truth areas. This simple, inexpensive technology shows promise for postoperative monitoring of dysesthesia surrounding surgical scars.