416 research outputs found
Analyzing labor supply behavior with latent job opportunity sets and institutional choice constraints.
In this paper we discuss a general framework for analyzing labor supply behavior in the presence of complicated budget- and quantity constraints of which some may be unobservable. The point of departure is that an individual's labor supply decision can be considered as a choice from a set of discrete alternatives (jobs). These jobs are characterized by attributes such as hours of work, sector specific wages and other sector specific aspects of the jobs. We focus in particular on theoretical justification of functional form assumptions and properties of the random components of the model. The paper also includes an empirical application based on Norwegian data, in which the labor supply of married women is estimated.Labor supply; non-convex budget sets; non-pecuniary job-attributes; sector-specific wages
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
Fluid-sensitive migration mechanisms predict association between metastasis and high interstitial fluid pressure in pancreatic cancer
A remarkable feature in pancreatic cancer is the propensity to metastasize early, even for small, early stage cancers. We use a computer-based pancreatic model to simulate tumor progression behavior where fluid-sensitive migration mechanisms are accounted for as a plausible driver for metastasis. The model has been trained to comply with in vitro results to determine input parameters that characterize the migration mechanisms. To mimic previously studied preclinical xenografts we run the computer model informed with an ensemble of stochastic-generated realizations of unknown parameters related to tumor microenvironment only constrained such that pathological realistic values for interstitial fluid pressure (IFP) are obtained. The in silico model suggests the occurrence of a steady production of small clusters of cancer cells that detach from the primary tumor and form isolated islands and thereby creates a natural prerequisite for a strong invasion into the lymph nodes and venous system. The model predicts that this behavior is associated with high interstitial fluid pressure (IFP), consistent with published experimental findings. The continuum-based model is the first to explain published results for preclinical models which have reported associations between high IFP and high metastatic propensity and thereby serves to shed light on possible mechanisms behind the clinical aggressiveness of pancreatic cancer.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
Pitx1 enhancer variants in spined and spine-reduced Subarctic European sticklebacks
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 listenerâalthough the listening does pose a considerable strain on the researcher
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