What role did skilled-biased technological change play in narrowing the gender wage gap? To answer that question this paper constructs a task-based Roy model in which workers possess a bundle of ...basic skills and occupations are characterized as a bundle of basic tasks. The model is estimated using the task data from the Dictionary of Occupational Titles (DOT) and the Panel Study of Income Dynamics (PSID). The main empirical finding is that men have more motor skills than women, but the returns to motor skills have dropped significantly, accounting for a major part of the narrowed gender wage gap from 1980 to 2000.
Nicotinamide adenine dinucleotide (NAD+) biosynthetic pathway, mediated by nicotinamide phosphoribosyltransferase (NAMPT), a key NAD+ biosynthetic enzyme, plays a pivotal role in controlling many ...biological processes, such as metabolism, circadian rhythm, inflammation, and aging. Over the past decade, NAMPT‐mediated NAD+ biosynthesis, together with its key downstream mediator, namely the NAD+‐dependent protein deacetylase SIRT1, has been demonstrated to regulate glucose and lipid metabolism in a tissue‐dependent manner. These discoveries have provided novel mechanistic and therapeutic insights into obesity and its metabolic complications, such as insulin resistance, an important risk factor for developing type 2 diabetes and cardiovascular disease. This review will focus on the importance of adipose tissue NAMPT‐mediated NAD+ biosynthesis and SIRT1 in the pathophysiology of obesity and insulin resistance. We will also critically explore translational and clinical aspects of adipose tissue NAD+ biology.
Obesity‐associated insulin resistance is an important risk factor for type 2 diabetes and cardiovascular disease. Emerging evidence suggests that impairment of adipose tissue NAMPT‐NAD+‐SIRT1 axis leads to the development of insulin resistance in multiple metabolic organs. These findings have provided important mechanistic and clinical insights into obesity and insulin resistance.
This paper constructs and estimates a dynamic discrete choice structural model of female employment and fertility decisions that incorporates job protection and cash benefits of parental leave ...legislation. The structural model is used for ex ante evaluation of policies that change the duration of job protection and/or the arrangement for cash benefits. Counterfactual simulations indicate that introducing an initial 1-year job protection policy increases maternal employment significantly, but extending the existing job protection period from 1 to 3 years has little effect. In addition, the employment effects of cash benefits seem modest. Overall, parental leave policies have little effect on fertility.
Recent studies have revealed that decline in cellular nicotinamide adenine dinucleotide (NAD+) levels causes aging-related disorders and therapeutic approaches increasing cellular NAD+ prevent these ...disorders in animal models. The administration of nicotinamide mononucleotide (NMN) has been shown to mitigate aging-related dysfunctions. However, the safety of NMN in humans have remained unclear. We, therefore, conducted a clinical trial to investigate the safety of single NMN administration in 10 healthy men. A single-arm non-randomized intervention was conducted by single oral administration of 100, 250, and 500 mg NMN. Clinical findings and parameters, and the pharmacokinetics of NMN metabolites were investigated for 5 h after each intervention. Ophthalmic examination and sleep quality assessment were also conducted before and after the intervention. The single oral administrations of NMN did not cause any significant clinical symptoms or changes in heart rate, blood pressure, oxygen saturation, and body temperature. Laboratory analysis results did not show significant changes, except for increases in serum bilirubin levels and decreases in serum creatinine, chloride, and blood glucose levels within the normal ranges, independent of the dose of NMN. Results of ophthalmic examination and sleep quality score showed no differences before and after the intervention. Plasma concentrations of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-5-carboxamide were significantly increased dose-dependently by NMN administration. The single oral administration of NMN was safe and effectively metabolized in healthy men without causing any significant deleterious effects. Thus, the oral administration of NMN was found to be feasible, implicating a potential therapeutic strategy to mitigate aging-related disorders in humans.
This paper estimates the effects of school closure on students’ study time and the number of messages sent from teachers to students using an online learning service. We find that both study time and ...message numbers increased significantly from the beginning of the school closure but they returned to pre-COVID-19 levels when the state of emergency ended in late May 2020. In addition, we find that students with prior access to the online learning service at home and students at higher-quality schools increased their study time more than other students. However, we find no gender differences in these outcomes.
The intestine has garnered attention as a target organ for developing new therapies for impaired glucose tolerance. The intestine, which produces incretin hormones, is the central regulator of ...glucose metabolism. Glucagon-like peptide-1 (GLP-1) production, which determines postprandial glucose levels, is regulated by intestinal homeostasis. Nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD
) biosynthesis in major metabolic organs such as the liver, adipose tissue, and skeletal muscle plays a crucial role in obesity- and aging-associated organ derangements. Furthermore, NAMPT-mediated NAD
biosynthesis in the intestines and its upstream and downstream mediators, adenosine monophosphate-activated protein kinase (AMPK) and NAD
-dependent deacetylase sirtuins (SIRTs), respectively, are critical for intestinal homeostasis, including gut microbiota composition and bile acid metabolism, and GLP-1 production. Thus, boosting the intestinal AMPK-NAMPT-NAD
-SIRT pathway to improve intestinal homeostasis, GLP-1 production, and postprandial glucose metabolism has gained significant attention as a novel strategy to improve impaired glucose tolerance. Herein, we aimed to review in detail the regulatory mechanisms and importance of intestinal NAMPT-mediated NAD
biosynthesis in regulating intestinal homeostasis and GLP-1 secretion in obesity and aging. Furthermore, dietary and molecular factors regulating intestinal NAMPT-mediated NAD
biosynthesis were critically explored to facilitate the development of new therapeutic strategies for postprandial glucose dysregulation.
This paper examines how the COVID-19 pandemic affected female employment in Japan. Our estimates indicate that the employment rate of married women with children decreased by 3.5 percentage points, ...while that of those without children decreased by only 0.3 percentage points, implying that increased childcare responsibilities caused a sharp decline in mothers’ employment. Further, mothers who left or lost their jobs appear to have dropped out of the labor force even several months after school reopening. In contrast to women, the employment rate of married men with children was not affected, which hindered progress in narrowing the employment gender gap.
•We examine how the COVID-19 pandemic affected female employment in Japan.•A counterfactual employment rate is constructed from pre-pandemic employment data.•The COVID-19 negatively affected the employment rate of married women with children.•Most of the negative effect was accounted for by married women with younger children.•The progress in narrowing the gender employment gap has stalled under COVID-19.
•Childcare use increases mother’s labor supply and earnings.•The childcare reform crowds out some of informal childcare arrangements.•The treatment effect decreases with the age of the child.•The ...marginal treatment effect is negatively associated with the propensity to use childcare.
We estimate the marginal treatment effect of childcare use on mothers’ labor market outcomes by using a staggered expansion of childcare services across regions in Japan. The estimates show that the heterogeneous treatment effects are negatively associated with the propensity to use childcare, which implies that mothers who increase their labor supply the least when subjected to the treatment are those mothers with the highest underlying tendency to use childcare. Because the childcare rationing rule tends to allocate childcare slots to mothers who work full-time before they apply, the slots tend to go to mothers who have the strongest labor force attachment, who are also the mothers who tend to have the strongest propensity to use childcare.
Obesity is associated with adipose tissue dysfunction and multi-organ insulin resistance. However, the mechanisms of such obesity-associated systemic metabolic complications are not clear. Here, we ...characterized mice with adipocyte-specific deletion of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting NAD+ biosynthetic enzyme known to decrease in adipose tissue of obese and aged rodents and people. We found that adipocyte-specific Nampt knockout mice had severe insulin resistance in adipose tissue, liver, and skeletal muscle and adipose tissue dysfunction, manifested by increased plasma free fatty acid concentrations and decreased plasma concentrations of a major insulin-sensitizing adipokine, adiponectin. Loss of Nampt increased phosphorylation of CDK5 and PPARγ (serine-273) and decreased gene expression of obesity-linked phosphorylated PPARγ targets in adipose tissue. These deleterious alterations were normalized by administering rosiglitazone or a key NAD+ intermediate, nicotinamide mononucleotide (NMN). Collectively, our results provide important mechanistic and therapeutic insights into obesity-associated systemic metabolic derangements, particularly multi-organ insulin resistance.
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•Adipocyte-specific Nampt knockout (ANKO) mice have multi-organ insulin resistance•Loss of Nampt impairs adipose tissue function and decreases adiponectin production•ANKO mice display increased phosphorylation of CDK5 and PPARγ (serine-273)•Nicotinamide mononucleotide (NMN) normalizes metabolic derangements in ANKO mice
Obesity-associated insulin resistance is an important risk factor of type 2 diabetes and cardiovascular diseases. In this study, Stromsdorfer et al. demonstrate that adipocyte-specific inactivation of Nampt, a key NAD+ biosynthetic enzyme known to decrease in obese rodents and humans, causes insulin resistance in adipose tissue, liver, and skeletal muscle.
Retinal ischemia/reperfusion (I/R) injury can cause severe vision impairment. Retinal I/R injury is associated with pathological increases in reactive oxygen species and inflammation, resulting in ...retinal neuronal cell death. To date, effective therapies have not been developed. Nicotinamide mononucleotide (NMN), a key nicotinamide adenine dinucleotide (NAD+) intermediate, has been shown to exert neuroprotection for retinal diseases. However, it remains unclear whether NMN can prevent retinal I/R injury. Thus, we aimed to determine whether NMN therapy is useful for retinal I/R injury-induced retinal degeneration. One day after NMN intraperitoneal (IP) injection, adult mice were subjected to retinal I/R injury. Then, the mice were injected with NMN once every day for three days. Electroretinography and immunohistochemistry were used to measure retinal functional alterations and retinal inflammation, respectively. The protective effect of NMN administration was further examined using a retinal cell line, 661W, under CoCl2-induced oxidative stress conditions. NMN IP injection significantly suppressed retinal functional damage, as well as inflammation. NMN treatment showed protective effects against oxidative stress-induced cell death. The antioxidant pathway (Nrf2 and Hmox-1) was activated by NMN treatment. In conclusion, NMN could be a promising preventive neuroprotective drug for ischemic retinopathy.
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