Housing over time and over the life cycle: a structural estimation

We estimate a structural model of optimal life-cycle housing and consumption in the presence of realistic labor income and house price uncertainties. The model postulates constant elasticity of substitution between housing service and nonhousing consumption, and explicitly incorporates a house adjustment cost. Our estimation fits the cross-sectional and time-series household wealth and housing profiles from the Panel Study of Income Dynamics quite well, and suggests an intra-temporal elasticity of substitution between housing and nonhousing consumption of 0.33 and a housing adjustment cost that amounts to about 15 percent of house value. Policy experiments with estimated preference parameters imply that households respond nonlinearly to house price changes with large house price declines leading to sizable decreases in both the aggregate homeownership rate and aggregate non-housing consumption. The average marginal propensity to consume out of housing wealth changes ranges from 0.4 percent to 6 percent. When lending conditions are tightened in the form of a higher down payment requirement, interestingly, large house price declines result in more severe drops in the aggregate homeownership rate but milder decreases in nonhousing consumption.

A Case Study of the Acquisition of Mandarin Classifiers

In this paper, I examine the acquisition data of a Mandarin-speaking child Bao-Bao (2;2.7) to study his acquisition of Mandarin classifiers, which are obligatory when a demonstrative or a numeral occurs. I argue that despite the poor input from the caregiver, the child is aware of the classifier projection and the selectional syntactic relation within a Mandarin DP from an early age, which is consistent with the Strong Continuity Hypothesis (Lust 1999). I then offer arguments with respect to processing restrictions and syntactic parameter-setting to explain why the child omits and misuses classifiers. A phonological account will also be examined

Enhancing Student Engagement through Online Authentic Materials

Students exposed to authentic materials in the foreign languageclassroom are better able to process foreign language input in real-lifesituations and have a more positive attitude towards learning theforeign culture. However, exposure to authentic materials can alsoresult in reactions of anxiety and frustration on the part of the foreignlanguage learner. By providing access to authentic content online, thepedagogical benefits of the use of authentic material can be maximized,while some of the drawbacks inherent in such use can be mitigated. Inthis article, we discuss how the use of online technologies offersopportunities to provide access to authentic material that is engaging,appropriate, and affordable. By using the multi-media capabilities of aCourse Management System (CMS) to deliver authentic materialsonline, instructors of French, Italian, and Chinese were able to bothpositively impact student attitudes toward the subject matter and todesign learning and evaluation activities that increased studentengagement. We find that using technology to deliver authentic materials can help alleviate student anxiety associated with being exposed to authentic foreign language. Furthermore, students becomeactive participants in the learning process and are able to employ theirown learning style. We conclude by discussing the limitations andimplications of our findings and making suggestions for futureresearch

Parental compensatory behaviors and early child health outcomes in Cebu, Philippines

A dynamic optimization model of parents choosing investments in their children’s health motivates an empirical model of parents’ choices of health inputs for their children and the impacts of these decisions on their children’s subsequent health. Estimates of the child health input demand functions and the child health production functions from the Cebu Longitudinal Health and Nutrition Survey accord with the prediction that optimizing behavior results in higher levels of aggregate child health. Observable parental behaviors respond to the physical developmental status of their children. These parental responses appear to yield large and statistically significant improvements in children’s early physiological outcomes. However, because some health inputs choices are not observable, it is impossible to ascertain whether these measured effects are due solely to variations in the observed input choices

Measurement and Control System of Self-propelled Levelling Machine Based on Inclination Sensor and Laser

The measurement and control system of the self-propelled levelling machine adopts the software and hardware composing and the control mode based on inclination sensor and laser emitter. The system adopts the inclination sensor and laser emitter as the datum signal to form the datum plane. The separate time treatment avoids simultaneously adjusting inclination and laser signal to each other interfere. The hydraulic servo system controls the levelling part to work on the plane that parallels with the datum plane. The test result shows the measurement and control system satisfy with the request of the self-propelled levelling machine

Commute Times, Food Retail Gaps, and Body Mass Index in North Carolina Counties

Introduction: The prevalence of obesity is higher in rural than in urban areas of the United States, for reasons that are not well understood. We examined correlations between percentage of rural residents, commute times, food retail gap per capita, and body mass index (BMI) among North Carolina residents. Methods: We used 2000 census data to determine each county\u27s percentage of rural residents and 1990 and 2000 census data to obtain mean county-level commute times. We obtained county-level food retail gap per capita, defined as the difference between county-level food demand and county-level food sales in 2008, from the North Carolina Department of Commerce, and BMI data from the 2007 North Carolina Behavioral Risk Factor Surveillance System. To examine county-level associations between BMI and percentage of rural residents, commute times, and food retail gap per capita, we used Pearson correlation coefficients. To examine cross-sectional associations between individual-level BMI (n=9,375) and county-level commute times and food retail gap per capita, we used multilevel regression models. Results: The percentage of rural residents was positively correlated with commute times, food retail gaps, and county-level BMI. Individual-level BMI was positively associated with county-level commute times and food retail gaps. Conclusions: Longer commute times and greater retail gaps may contribute to the rural obesity disparity. Future research should examine these relationships longitudinally and should test community-level obesity prevention

Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-matter Interactions

Van der Waals (vdW) solids, as a new type of artificial materials that consist of alternating layers bonded by weak interactions, have shed light on fascinating optoelectronic device concepts. As a result, a large variety of vdW devices have been engineered via layer-by-layer stacking of two-dimensional materials, although shadowed by the difficulties of fabrication. Alternatively, direct growth of vdW solids has proven as a scalable and swift way, highlighted by the successful synthesis of graphene/h-BN and transition metal dichalcogenides (TMDs) vertical heterostructures from controlled vapor deposition. Here, we realize high-quality organic and inorganic vdW solids, using methylammonium lead halide (CH3NH3PbI3) as the organic part (organic perovskite) and 2D inorganic monolayers as counterparts. By stacking on various 2D monolayers, the vdW solids behave dramatically different in light emission. Our studies demonstrate that h-BN monolayer is a great complement to organic perovskite for preserving its original optical properties. As a result, organic/h-BN vdW solid arrays are patterned for red light emitting. This work paves the way for designing unprecedented vdW solids with great potential for a wide spectrum of applications in optoelectronics