346 research outputs found
A labor supply model for married couples with non-convex budget sets and latent rationing
The basic assumption in this paper is that individuals make their choices from a set of latent discrete alternatives, called matches. Given the match, hours of work, wages and non-pecuniary characteristics follow. This model allows for very general budget specifications as well as restrictions on job opportunities and hours of work. The model is estimated on Norwegian data from 1979. Some of the results are summarized in wage elasticities and it is demonstrated that they are in the range of what others have obtained. Moreover, aggregate elasticities Which reflect observed as well as unobserved heterogeneity are calculated. We also report estimates derived from alternative specifications of the budget set, ranging from ignorance of taxes at all to a detailed specification of all sorts of taxes and transfers. The results of tax policy simulations are included in the final section of the paper
Aggregate marginal costs of public funds
In this paper, we discuss aggregate measures of marginal costs of public funds (MCF) in populations that are heterogeneous with respect to observed as well as unobserved characteristics. We first discuss how to compute MCF in selected examples of traditional (textbook) labour supply models. Next, we review two types of discrete labour supply models proposed in the literature. Subsequently, we discuss how to calculate aggregate measures of MCF for discrete labour supply models. Finally, we apply an estimated two-sector discrete labour supply model to compute MCF based on Norwegian data
Aggregate marginal costs of public funds
In this paper, we discuss aggregate measures of marginal costs of public funds (MCF) in populations that are heterogeneous with respect to observed as well as unobserved characteristics. We first discuss how to compute MCF in selected examples of traditional (textbook) labour supply models. Next, we review two types of discrete labour supply models proposed in the literature. Subsequently, we discuss how to calculate aggregate measures of MCF for discrete labour supply models. Finally, we apply an estimated two-sector discrete labour supply model to compute MCF based on Norwegian data.publishedVersio
In silico investigations of intratumoral heterogeneous interstitial fluid pressure
Recent preclinical studies have shown that interstitial fluid pressure (IFP) within tumors can be heterogeneous Andersen et al. (2019). In that study tumors of two xenograft models, respectively, HL-16 cervical carcinoma and Panc-1 pancreatic carcinoma, were investigated. Significant heterogeneity in IFP was reported and it was proposed that this was associated with division of tissue into compartments separated by thick connective tissue bands for the HL-16 tumors and with dense collagen-rich extracellular matrix for the Panc-1 tumors. The purpose of the current work is to explore these experimental observations by using in silico generated tumor models. We consider a mathematical multiphase model which accounts for tumor cells, fibroblasts and interstitial fluid. The model has been trained to comply with experimental in vitro results reported in Shieh et al. (2011) which has identified autologous chemotaxis, ECM remodeling, and cell-fibroblast interaction as drivers for invasive tumor cell behavior. The in silico model is informed with parameters that characterize the leaky intratumoral vascular network, the peritumoral lymphatics which collect the fluid, and the density of ECM as represented through the hydraulic conductivity of the interstitial space. Heterogeneous distribution of solid stress may result in heterogeneous compression of blood vessels and, thus, heterogeneous vascular density inside the tumor. To mimic this we expose the in silico tumor to an intratumoral vasculature whose net effect of density of blood vesssels and vessel wall conductivity is varied through a 2D Gaussian variogram constrained such that the resulting IFPs lie within the range as reported from the preclinical study. The in silico cervical carcinoma model illustrates that sparse ECM was associated with uniform intratumoral IFP in spite of heterogeneous microvascular network, whereas compartment structures resulted in more heterogeneous IFP. Similarly, the in silico pancreatic model shows that heterogeneity in the microvascular network combined with dense ECM structure prevents IFP to even out and gives rise to heterogeneous IFP. The computer model illustrates how a heterogeneous invasive front might form where groups of tumor cells detach from the primary tumor and form isolated islands, a behavior which is natural to associate with metastatic propensity. However, unlike experimental studies, the current version of the in silico model does not show an association between metastatic propensity and elevated IFP.publishedVersio
Estradiol Valerate Vs. Ethinylestradiol In Combined Oral Contraceptives : Effects On The Pituitary-Ovarian Axis
Context There are limited studies comparing the effects of combined oral contraceptives (COCs) containing natural estrogens and synthetic ethinylestradiol (EE) on reproductive hormones. Objective To compare estradiol valerate (EV)+dienogest (DNG), EE+DNG, and DNG alone (an active control) on levels of follicle stimulating hormone (FSH), luteinizing hormone, Anti-Mullerian hormone (AMH), ovarian steroids, sex hormone binding globulin (SHBG), and the Free Androgen Index (FAI). Design Spin-off study from a randomized trial. Setting Outpatient setting at Helsinki and Oulu University Hospitals, Finland. Participants 59 healthy, 18-35-year-old ovulatory women were enrolled. Three women discontinued. The groups were comparable as regards age and body mass index. Interventions EV 2mg+DNG 2-3mg (n=20), EE 0.03mg+DNG 2mg (n=20) and DNG 2mg (n=19) were used continuously for nine weeks. Blood samples were drawn at baseline, and at 5 and 9 weeks. Main Outcome Measures EV+DNG suppressed FSH by -27% (-51:-3) (median [95%CI]) vs. EE+DNG, -64% (-78: -51), P=0.04, but AMH levels decreased similarly by -9% (-18: -0.1) vs. -13% (-28:0.2), P=0.38, respectively. EV+DNG increased SHBG levels by 56% (30:82) and EE+DNG by 385% (313:423), PPeer reviewe
Researching the lived experiences of cancer patients with malignant fungating wounds
Background: Researching the experiences of terminally ill patients with disfiguring wounds is likely to be a challenge anywhere, and this investigation came face-to-face with different attitudes on the part of both patients and nurses and doctors in England (the South-East) and Italy (Tuscany).
Aim: To highlight the complexity of researching sensitive subjects and the difficulties encountered from the perspective of the researcher(s).
Methods: Fourteen patients were interviewed. In England access was relatively straightforward, with nurses linked to the hospice doing most of the recruitment. Access was more difficult in Italy, with some doctors expressing opposition.
Discussion: How ethical is it to treat dying patients as subjects for research? How does research of this kind vary from one culture to another?
Conclusions: Interviewees can find it therapeutic to talk about their experiences to a sympathetic listener—although the listening does pose a considerable strain on the researcher
Circulating antimullerian hormone and steroid hormone levels remain high in pregnant women with polycystic ovary syndrome at term
Objective: To investigate plasma antimullerian hormone (AMH) concentration and its relation to steroid hormone levels in pregnant women with polycystic ovary syndrome (PCOS) and controls at term. Design: Case-control study. Setting: University-affiliated hospital. Patient(s): A total of 74 pregnant women at term: 25 women with PCOS (aged 31.6 +/- 3.9 years [mean +/- standard deviation], body mass index 24.0 +/- 3.9 kg/m2, mean gestational length 279 +/- 9 days) and 49 controls (aged 31.7 +/- 3.3 years, body mass index 24.0 +/- 3.3 kg/m2, mean gestational length 281 +/- 9 days). Intervention(s): None. Main Outcome Measure(s): Plasma AMH and steroid hormone levels. Result(s): Antimullerian hormone, T, and androstenedione levels were higher in women with PCOS at term compared with controls, whereas estrogen and P levels were similar. The differences were pronounced in women carrying a female fetus. Testosterone and AMH levels correlated positively in both groups, but E2 levels only in women with PCOS. Conclusion(s): Pregnant women with PCOS present with elevated AMH and androgen levels even at term, suggesting a hormonal imbalance during PCOS pregnancy. Differences were detected especially in pregnancies with a female fetus, raising the question of whether female pregnancies are more susceptible to AMH and steroid hormone actions. (C) Copyright (C) 2018 The Authors. Published by Elsevier Inc. on behalf of the American Society for Reproductive Medicine. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer reviewe
Biomarker responses and accumulation of polycyclic aromatic hydrocarbons in Mytilus trossulus and Gammarus oceanicus during exposure to crude oil
In the brackish water Baltic Sea, oil pollution is an ever-present and significant environmental threat mainly due to the continuously increasing volume of oil transport in the area. In this study, effects of exposure to crude oil on two common Baltic Sea species, the mussel Mytilus trossulus and the amphipod Gammarus oceanicus, were investigated. The species were exposed for various time periods (M. trossulus 4, 7, and 14 days, G. oceanicus 4 and 11 days) to three oil concentrations (0.003, 0.04, and 0.30 mg L−1 based on water measurements, nominally aimed at 0.015, 0.120, and 0.750 mg L−1) obtained by mechanical dispersion (oil droplets). Biological effects of oil exposure were examined using a battery of biomarkers consisting of enzymes of the antioxidant defense system (ADS), lipid peroxidation, phase II detoxification (glutathione S-transferase), neurotoxicity (acetylcholinesterase inhibition), and geno- and cytotoxicity (micronuclei and other nuclear deformities). In mussels, the results on biomarker responses were examined in connection with data on the tissue accumulation of polycyclic aromatic hydrocarbons (PAH). In M. trossulus, during the first 4 days of exposure the accumulation of all PAHs in the two highest exposure concentrations was high and was thereafter reduced significantly. Significant increase in ADS responses was observed in M. trossulus at 4 and 7 days of exposure. At day 14, significantly elevated levels of geno- and cytotoxicity were detected in mussels. In G. oceanicus, the ADS responses followed a similar pattern to those recorded in M. trossulus at day 4; however, in G. oceanicus, the elevated ADS response was still maintained at day 11. Conclusively, the results obtained show marked biomarker responses in both study species under conceivable, environmentally realistic oil-in-seawater concentrations during an oil spill, and in mussels, they are related to the observed tissue accumulation of oil-derived compounds
Recommended from our members
Satellite-based time-series of sea-surface temperature since 1981 for climate applications
A climate data record of global sea surface temperature (SST) spanning 1981–2016 has been developed from 4 × 10^12 satellite measurements of thermal infra-red radiance. The spatial area represented by pixel SST estimates is between 1 km^2 and 45 km^2. The mean density of good-quality observations is 13 km^−2 yr^−1. SST uncertainty is evaluated per datum, the median uncertainty for pixel SSTs being 0.18 K. Multi-annual observational stability relative to drifting buoy measurements is within 0.003 K yr^−1 of zero with high confidence, despite maximal independence from in situ SSTs over the latter two decades of the record. Data are provided at native resolution, gridded at 0.05° latitude-longitude resolution (individual sensors), and aggregated and gap-filled on a daily 0.05° grid. Skin SSTs, depth-adjusted SSTs de-aliased with respect to the diurnal cycle, and SST anomalies are provided. Target applications of the dataset include: climate and ocean model evaluation; quantification of marine change and variability (including marine heatwaves); climate and ocean-atmosphere processes; and specific applications in ocean ecology, oceanography and geophysics
- …