Community environment, cognitive impairment and dementia in later life: results from the Cognitive Function and Ageing Study

Background: Few studies have investigated the impact of the community environment, as distinct from area deprivation, on cognition in later life. This study explores cross-sectional associations between cognitive impairment and dementia and environmental features at the community level in older people. Method: The postcodes of the 2424 participants in the year-10 interview of the Cognitive Function and Ageing Study in England were mapped into small area level geographical units (Lower-layer Super Output Areas) and linked to environmental data in government statistics. Multilevel logistic regression was conducted to investigate associations between cognitive impairment (defined as MMSE3 in GMS-AGECAT) and community level measurements including area deprivation, natural environment, land use mix and crime. Sensitivity analyses tested the impact of people moving residence within the last two years. Results: Higher levels of area deprivation and crime were not significantly associated with cognitive impairment and dementia after accounting for individual level factors. Living in areas with high land use mix was significantly associated with a nearly 60% reduced odds of dementia (OR: 0.4; 95% CI: 0.2, 0.8) after adjusting for individual level factors and area deprivation, but there was no linear trend for cognitive impairment. Increased odds of dementia (OR: 2.2, 95% CI: 1.2, 4.2) and cognitive impairment (OR: 1.4, 95% CI: 1.0, 2.0) were found in the highest quartile of natural environment availability. Findings were robust to exclusion of the recently relocated. Conclusion: Features of land use have complex associations with cognitive impairment and dementia. Further investigations should focus on environmental influences on cognition to inform health and social policies

Community environment, cognitive impairment and dementia in later life: results from the Cognitive Function and Ageing Study

Background: Few studies have investigated the impact of the community environment, as distinct from area deprivation, on cognition in later life. This study explores cross-sectional associations between cognitive impairment and dementia and environmental features at the community level in older people. Method: The postcodes of the 2424 participants in the year-10 interview of the Cognitive Function and Ageing Study in England were mapped into small area level geographical units (Lower-layer Super Output Areas) and linked to environmental data in government statistics. Multilevel logistic regression was conducted to investigate associations between cognitive impairment (defined as MMSE3 in GMS-AGECAT) and community level measurements including area deprivation, natural environment, land use mix and crime. Sensitivity analyses tested the impact of people moving residence within the last two years. Results: Higher levels of area deprivation and crime were not significantly associated with cognitive impairment and dementia after accounting for individual level factors. Living in areas with high land use mix was significantly associated with a nearly 60% reduced odds of dementia (OR: 0.4; 95% CI: 0.2, 0.8) after adjusting for individual level factors and area deprivation, but there was no linear trend for cognitive impairment. Increased odds of dementia (OR: 2.2, 95% CI: 1.2, 4.2) and cognitive impairment (OR: 1.4, 95% CI: 1.0, 2.0) were found in the highest quartile of natural environment availability. Findings were robust to exclusion of the recently relocated. Conclusion: Features of land use have complex associations with cognitive impairment and dementia. Further investigations should focus on environmental influences on cognition to inform health and social policies

The Viscosity Parameter for Late-type Stable Be Stars

Fil: Granada, Anahi. Universidad Nacional de Rio Negro, CITECCA. Río Negro, Argentina.Fil: Jones, Carol E. University of Western Ontario, CanadaFil: Sigut, Aaron. University of Western Ontario, CanadaUsing hydrodynamic principles we investigate the nature of the disk viscosity following the parameterization by Shakura & Sunyaev adopted for the viscous decretion model in classical Be stars. We consider a radial viscosity distribution including a constant value, a radially variable α assuming a power-law density distribution, and isothermal disks, for a late-B central star. We also extend our analysis by determining a self-consistent temperature disk distribution to model the late-type Be star 1 Delphini, which is thought to have a nonvariable, stable disk as evidenced by Hα emission profiles that have remained relatively unchanged for decades. Using standard angular momentum loss rates given by Granada et al., we find values of α of approximately 0.3. Adopting lower values of angular momentum loss rates, i.e., smaller mass loss rates, leads to smaller values of α. The values for α vary smoothly over the Hα emitting region and exhibit the biggest variations nearest the central star within about five stellar radii for the late-type, stable Be stars.Utilizando principios hidrodinámicos investigamos la naturaleza de la viscosidad del disco siguiendo la parametrización de Shakura & Sunyaev adoptada para el modelo de decrecimiento viscoso en estrellas Be clásicas. Consideramos una distribución de viscosidad radial que incluye un valor constante, una variable radial α asumiendo una distribución de densidad de ley de potencia, y discos isotérmicos, para una estrella central B tardía. También ampliamos nuestro análisis determinando una distribución de temperatura de disco autoconsistente para modelar la estrella Be de tipo tardío 1 Delphini, que se cree que tiene un disco estable no variable, como demuestran los perfiles de emisión Hα que han permanecido relativamente sin cambios durante décadas. Utilizando las tasas estándar de pérdida de momento angular dadas por Granada et al., encontramos valores de α de aproximadamente 0,3. La adopción de valores más bajos de tasas de pérdida de momento angular, es decir, tasas de pérdida de masa más pequeñas, conduce a valores más pequeños de α. Los valores de α varían suavemente sobre la región de emisión de Hα y exhiben las mayores variaciones más cercanas a la estrella central dentro de unos cinco radios estelares para las estrellas Be estables de tipo tardío. Traducción realizada con la versión gratuita de Deep

Scratch and Win! - Immediate Feedback in Physics Multiple-Choice Quizzes and Exams

Multiple-choice (MC) exams allow a large range of topics to be efficiently tested. However, the effort required to construct a good MC exam—one that tests comprehension and ability to apply knowledge, rather than rote memorization—leads to a reluctance to release solutions, thus limiting the value of the exam to students. Furthermore, students often do not spend the time necessary to review the MC portion of graded exams and may not be aware of their weaknesses with a particular topic in the syllabus. We employed a recent innovation that provides feedback from MC questions, the Immediate Feedback Assessment Technique (IFAT), in a standard first-year Physics course. In this scheme, students respond to MC questions by scratching off a thin, opaque covering from the rectangle corresponding to their answer on a special answer card similar to a “scratch and win” lottery ticket. If their answer is correct, they uncover a star and receive full credit. In the event of a wrong answer they may reconsider their response, and scratch again to earn partial credit. Students thereby receive immediate feedback on their answers, turning the examination itself into a learning experience. It is relatively simple to implement this form of assessment at your institution. The IFAT cards are available for purchase from Epstein Educational Enterprises. However, there are some obstacles. Since machine grading of the IFAT cards is not available, we relied on additional graduate student support for this purpose. We will also discuss the new forms of cheating attempted by students as well as difficulties we encountered constructing our tests with the IFAT system. Based on standardized tests and comparison with a control group, we found that students improved their performance using the IFAT system, with the largest gains seen for conceptually difficult questions. Furthermore, based on an exit survey, students in the study strongly preferred this method of MC testing

Comparison of the Uptake and Metabolism of Retinol Delivered to Primary Mouse Keratinocytes Either Free or Bound to Rat Serum Retinol-binding Protein

Serum retinol-binding protein (RBP) is believed to be responsible for the transport of retinol from its storage site in the liver to vitamin A requiring target cells such as keratinocytes. We have used primary mouse keratinocytes as a model system to compare the uptake and metabolism of [3H] retinol delivered to them either free in solution or bound to RBP. RBP was purified from rat serum, loaded with [3H]retinol, and the [3H]retinol-RBP complex purified by affinity chromatography on human transthyretin-Sepharose. Keratinocytes incubated with either free [3H]retinol or [3H]retinal-RBP complex accumulated [3H]retinol in a time and temperature dependent manner, However, cells incubated with free [3H]retinol acquired 15- to 20-fold more ligand than if the retinol was delivered via RBP. The uptake of free [3H]retinol or [3H]retinol from RBP was not inhibited by excess unlabeled free retinol. The uptake of [3H]retinol from RBP was inhibited by high concentrations of holo-RBP, with half maximal inhibition occurring at 3μM holo-RBP. However, no specific binding of 125I-labeled RBP to monolayers of keratinocytes or membranes prepared from them was found indicating the absence of a high affinity RBP receptor on keratinocytes. Surprisingly, 50% of the [3H]retinol delivered to the keratinocytes during a 30-min uptake period was released from them within 30-min irrespective of whether or not it was initially delivered to them as free [3H]retinol or bound to RBP. The remaining 50% was lost at a much slower rate, but only 20% remained 24-h after delivery. Studies on retinol metabolism demonstrated that 7%12% of the total cell-associated [3H]retinol delivered during a 90-min uptake period was esterified (mostly as retinyl palmitate) whether or not it was given free in solution or bound to RBP