Does Indivisible Labor Explain the Difference Between Micro and Macro Elasticities? A Meta-Analysis of Extensive Margin Elasticities

Macroeconomic calibrations imply much larger labor supply elasticities than microeconometric studies. One prominent explanation for this divergence is that indivisible labor generates extensive margin responses that are not captured in micro studies of hours choices. We evaluate whether existing calibrations of macro models are consistent with micro evidence on extensive margin responses using two approaches. First, we use a standard calibrated macro model to simulate the impacts of tax policy changes on labor supply. Second, we present a meta-analysis of quasi-experimental estimates of extensive margin elasticities. We find that micro estimates are consistent with macro evidence on the steady-state (Hicksian) elasticities relevant for cross-country comparisons. However, micro estimates of extensive-margin elasticities are an order of magnitude smaller than the values needed to explain business cycle fluctuations in aggregate hours. Hence, indivisible labor supply does not explain the large gap between micro and macro estimates of intertemporal substitution (Frisch) elasticities. Our synthesis of the micro evidence points to Hicksian elasticities of 0.3 on the intensive and 0.25 on the extensive margin and Frisch elasticities of 0.5 on the intensive and 0.25 on the extensive margin.

Are There Returns to Experience at Low-Skill Jobs? Evidence from Single Mothers in the United States over the 1990s

Policy changes in the United States in the 1990s resulted in sizable increases in employment rates of single mothers. We show that this increase led to a large and abrupt increase in work experience for single mothers with young children. We then examine the economic return to this increase in experience for affected single mothers. Despite the increases in experience, single mothers’ real wages and employment have remained relatively unchanged. The empirical analysis suggests that an additional year of experience increases single mothers’ wage rates by less than 2 percent, a percentage lower than previous estimates in the literature

Maternal and perinatal outcome in placenta previa: an observational study at a tertiary care hospital in Mysore, Karnataka, India

Background: 2-5% of the pregnancies are complicated by antepartum haemorrhage. About one third of them are due to placenta previa thus contributing to a significant amount of maternal and perinatal morbidity and mortality. In the present times with liberally increasing caesarean section rates, there is a changing trend in the incidence and complications of placenta previa. The objective of this study was to evaluate the obstetrical characteristics and maternal and perinatal outcome of cases of placenta previa.Methods: This was a prospective observational study conducted in the Department of Obstetrics and Gynaecology of JSS Medical College and Hospital, Mysore during the period January 2017 to June 2018.Results: Out of total 13,150 deliveries during this period, placenta previa was observed in 131 cases with an incidence of 1%. Majority belonged to the age group 25-29 years (48.8%). 66% of the cases presented with painless vaginal bleeding as their chief complaint. The major risk factor was previous caesarean delivery seen in 29.8% cases followed by history of abortion in 18.3%. 67% cases had major degree placenta previa. Remaining 33% cases had minor degree. One case was complicated by placenta accrete. Peripartum hysterectomy was performed in 3.1%. Preterm deliveries amounted to 29.8%. Maternal and perinatal mortality were 0.76% and 3.05% respectively. 10.7% cases had Postpartum haemorrhage and 3.8% required ICU admission. 25% neonates required NICU admissions and 10% had RDS.Conclusions: Placenta previa is a prime contributor to substantial maternal and perinatal morbidity and mortality. Early referral to tertiary care centres, anticipation of clinical complications and appropriate measures can avoid grave consequences. Such cases must always be managed at a higher centre with good NICU services and round the clock operation theatre and blood bank facility

Nonparametric Evidence on the Effects of Financial Incentives on Retirement Decisions

This paper presents new empirical evidence on the effects of retirement benefits on labor force participation decisions. We use administrative data on the census of private sector employees in Austria and variation from mandated discontinuous changes in retirement benefits from the Austrian pension system. We present graphical evidence documenting labor supply responses to the policy discontinuities. Next, we develop nonparametric procedures to estimate labor supply elasticities based on the graphical evidence and mandated financial incentives. We estimate elasticities of 0.12 for men and 0.38 for women. These relatively low elasticities highlight that many retirement decisions are likely to be affected by factors beyond only financial incentives from retirement benefits.

Seasonal hysteresis of surface urban heat islands

Temporal dynamics of urban warming have been extensively studied at the diurnal scale, but the impact of background climate on the observed seasonality of surface urban heat islands (SUHIs) remains largely unexplored. On seasonal time scales, the intensity of urban–rural surface temperature differences (ΔTs) exhibits distinctive hysteretic cycles whose shape and looping direction vary across climatic zones. These observations highlight possible delays underlying the dynamics of the coupled urban–biosphere system. However, a general argument explaining the observed hysteretic patterns remains elusive. A coarse-grained model of SUHI coupled with a stochastic soil water balance is developed to demonstrate that the time lags between radiation forcing, air temperature, and rainfall generate a rate-dependent hysteresis, explaining the observed seasonal variations of ΔTs. If solar radiation is in phase with water availability, summer conditions cause strong SUHI intensities due to high rural evaporative cooling. Conversely, cities in seasonally dry regions where evapotranspiration is out of phase with radiation show a summertime oasis effect controlled by background climate and vegetation properties. These seasonal patterns of warming and cooling have significant implications for heat mitigation strategies as urban green spaces can reduce ΔTs during summertime, while potentially negative effects of albedo management during winter are mitigated by the seasonality of solar radiation

The Control Of Zealactone Biosynthesis And Exudation Is Involved In The Response To Nitrogen In Maize Root.

Nitrate acts as a signal in regulating plant development in response to environment. In particular nitric oxide (NO), auxin and strigolactones (SLs) were supposed to cooperate to regulate the maize root response to this anion. In this study, a combined approach based on LC-MS/MS and on physiological and molecular analyses was adopted to specify the involvement of SLs in the maize response to N. Our results showed that N deficiency strongly induces SL exudation, likely through stimulating their biosynthesis. Nitrate provision early counteracts and also ammonium lowers SL exudation, but less markedly. Exudates obtained from N-starved and ammonium-provided seedlings stimulated Phelipanche germination, whereas when seeds were treated with exudates harvested from nitrate-provided plants no germination was observed. Furthermore, our findings support the idea that the inhibition of SL production observed in response to nitrate and ammonium would contribute to the regulation of lateral root development. Moreover, the transcriptional regulation of a gene encoding a putative maize WBC transporter, in response to various nitrogen supplies, together with its mRNA tissue localization, supported its role in SL allocation. Our results highlight the dual role of SLs as molecules able to signal outwards a nutritional need and as endogenous regulators of root architecture adjustments to N, thus synchronizing plant growth with nitrogen acquisitio

Global convergence of COVID-19 basic reproduction number and estimation from early-time SIR dynamics

The SIR ('susceptible-infectious-recovered') formulation is used to uncover the generic spread mechanisms observed by COVID-19 dynamics globally, especially in the early phases of infectious spread. During this early period, potential controls were not effectively put in place or enforced in many countries. Hence, the early phases of COVID-19 spread in countries where controls were weak offer a unique perspective on the ensemble-behavior of COVID-19 basic reproduction number Ro inferred from SIR formulation. The work here shows that there is global convergence (i.e., across many nations) to an uncontrolled Ro = 4.5 that describes the early time spread of COVID-19. This value is in agreement with independent estimates from other sources reviewed here and adds to the growing consensus that the early estimate of Ro = 2.2 adopted by the World Health Organization is low. A reconciliation between power-law and exponential growth predictions is also featured within the confines of the SIR formulation. The effects of testing ramp-up and the role of 'super-spreaders' on the inference of Ro are analyzed using idealized scenarios. Implications for evaluating potential control strategies from this uncontrolled Ro are briefly discussed in the context of the maximum possible infected fraction of the population (needed to assess health care capacity) and mortality (especially in the USA given diverging projections). Model results indicate that if intervention measures still result in Ro > 2.7 within 44 days after first infection, intervention is unlikely to be effective in general for COVID-19

An ecohydrological journey of 4500 years reveals a stable but threatened precipitation–groundwater recharge relation around Jerusalem

Groundwater is a key water resource in semiarid and seasonally dry regions around the world, which is replenished by intermittent precipitation events and mediated by vegetation, soil, and regolith properties. Here, a climate reconstruction of 4500 years for the Jerusalem region was used to determine the relation between climate, vegetation, and groundwater recharge. Despite changes in air temperature and vegetation characteristics, simulated recharge remained linearly related to precipitation over the entire analyzed period, with drier decades having lower rates of recharge for a given annual precipitation due to soil memory effects. We show that in recent decades, the lack of changes in the precipitation–groundwater recharge relation results from the compensating responses of vegetation to increasing CO2, i.e., increased leaf area and reduced stomatal conductance. This multicentury relation is expected to be modified by climate change, with changes up to −20% in recharge for unchanged precipitation, potentially jeopardizing water resource availability