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“Golden Ages”: A Tale of the Labor Markets in China and the United States
Get PDFWe study the labor markets in China and the United States, the two largest economies in the world, by examining the evolution of their cross-sectional age-earnings profiles during the past thirty years. We find that, first, the peak age in the cross-sectional age-earnings profiles, which we refer to as the “golden age,” stayed almost constant at around 45-50 in the U.S., but decreased sharply from 55 to around 35 in China; second, the age-specific earnings grew drastically in China, but stayed almost stagnant in the U.S.; third, the cross-sectional and life-cycle age-earnings profiles were remarkably similar in the U.S., but differed substantially in China. We propose and empirically implement a decomposition framework to infer from the repeated cross-sectional earnings data the experience effect (i.e., human capital accumulation over the life cycle), the cohort effect (i.e., inter-cohort human capital growth), and the time effect (i.e., changes in the human capital rental prices over time), under an identifying assumption that the growth of the experience effect stops at the end of one’s working career. The decomposition suggests that China has experienced a much larger inter-cohort productivity growth and higher increase in the rental price to human capital, but lower returns to experience, compared to the U.S. We also use the inferred components to revisit several important and classical applications in macroeconomics and labor economics, including growth accounting and the estimation of TFP growth, and the college wage premium and skill-biased technical change
Financial Fragility during the COVID-19 Pandemic
Get PDFEarly in the COVID-19 pandemic, much of the US economy was closed to limit the virus’ spread, and several emergency interventions were implemented. Our analysis of older (45-75) respondents fielded in April-May of 2020 indicates that about one in five respondents was financially fragile and would have difficulty facing a mid-size emergency expense. Some subgroups were at particular risk of facing financial difficulties, especially younger respondents, those with larger families, Hispanics, and the low income. Moreover, the more financially literate were better able to handle such shocks, indicating that knowledge can provide some additional protection during a pandemic
Motivation dynamics for autonomous composition of navigation tasks
Get PDFWe physically demonstrate a reactive sensorimotor architecture for mobile robots whose behaviors are generated by motivation dynamics. Motivation dynamics uses a continuous dynamical system to reactively compose low-level control vector fields using valuation functions which capture the potentially competing influences of external stimuli relative to the system\u27s own internal state. We show that motivation dynamics 1) naturally accommodates external stimuli through standard signal processing tools, and 2) can effectively encode a repetitive higher-level task by composing several low-level controllers to achieve a limit cycle in which the robot repeatedly navigates towards two alternatively valuable goal locations in a commensurately alternating order. We show that these behaviors are robust to perturbations including imperfect models of robot kinematics, sensor noise, and disturbances resulting from the need to traverse difficult terrain. We argue that motivation dynamics can provide a useful alternative to controllers based on hybrid automata in situations where the control operates at a low level close to the physical hardware.
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The Influences of the Central European Jewish Refugees on the Chinese Community in Shanghai During World War II
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Scheduling Events Using the REDCap Calendar Application
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Recruitment and Functions of Myeloid Cells at the Intersection of Inflammation & Remodeling
No full textInflammation and tissue remodeling are often presented as two related, yet distinct, processes. Inflammation serves as a critical defense mechanism to destroy and clear pathogens or damaged tissue. Damaged tissue undergoes tissue remodeling, a process of reorganization that functions to maintain physiological homeostasis. Many key regulators of inflammation and tissue remodeling are shared between the two processes, yet their precise functions remain poorly understood. We sought to understand the role of pro-inflammatory circulating factors in pathological tissue remodeling using cutaneous wound healing as a model. Wounded skin remodels poorly, resulting in fibrotic scars. We observed that aging promoted tissue regeneration in the skin. In parabiosis experiments, young mice with cutaneous wounds healed with fibrosis and scar formation while aged mice healed with full-thickness tissue regeneration. Through these experiments, we identified stromal-derived factor-1 (SDF1) as a pro-fibrotic cytokine in the skin. Aging increased recruitment of enhancer of zeste homologue 2 (EZH2) and histone H3 lysine 27 trimethylation (H3K27me3) to the Sdf1 promoter. Similarly, silencing epidermal Sdf1 in young mouse skin enhanced in vivo tissue regeneration. SDF1 is a well-known mediator of macrophages. One of the key components of tissue remodeling are macrophages, which are essential for clearing apoptotic cells and remodeling the extracellular matrix. Given that crosstalk between tissues and macrophages is modulated by cytokines, we then considered the functions of a novel IL-15 responsive CD122+ macrophage population identified in the placenta, another actively remodeling tissue. In this context, we made the striking observation that CD122+ macrophages developed under the direction of interferons. Considering the canonical importance of interferons in anti-viral responses, we hypothesized that CD122+ macrophages play a critical role in promoting viral clearance. Using LCMV as a murine model of acute viral infection, we demonstrated that CD122+ macrophages modulate the abundance of CD8+ T-cells. Thus, the same macrophage phenotype found in an actively remodeling tissue also promotes an inflammatory anti-viral response. Taken together, the results presented in this dissertation highlight the role of macrophages at the intersection of tissue remodeling and anti-viral responses
Sagittal and Vertical Growth of the Maxillo–Mandibular Complex in Untreated Children: A Longitudinal Study on Lateral Cephalograms Derived from Cone Beam Computed Tomography
Get PDFThe aim of this longitudinal study was to evaluate the sagittal and vertical growth of the maxillo–mandibular complex in untreated children using orthogonal lateral cephalograms com-pressed from cone beam computed tomography (CBCT). Two sets of scans, on 12 males (mean 8.75 years at T1, and 11.52 years at T2) and 18 females (mean 9.09 years at T1, and 10.80 years at T2), were analyzed using Dolphin 3D imaging. The displacements of the landmarks and rotations of both jaws relative to the cranial base were measured using the cranial base, and the maxillary and mandibular core lines. From T1 to T2, relative to the cranial base, the nasion, orbitale, A-point, and B-point moved anteriorly and inferiorly. The porion moved posteriorly and inferiorly. The ANB and mandibular plane angle decreased. All but one subject had forward rotation in reference to the cranial base. The maxillary and mandibular superimpositions showed no sagittal change on the A-point and B-point. The U6 and U1 erupted at 0.94 and 1.01 mm/year (males) and 0.82 and 0.95 mm/year (females), respectively. The L6 and L1 erupted at 0.66 and 0.88 mm/year (males), and at 0.41 mm/year for both the L6 and the L1 (females), respectively. © 2021 by the authors. Licensee MDPI, Basel, Switzerland