Parental Leave Policies and Second Births: A Comparison of Czechia and Slovakia

Population Research and Policy Review - The paper investigates the transition to second births in Czechia and Slovakia in the context of the development of parental leave policies since the...     

On the asymptotic normality of the R-estimators of the slope parameters of simple linear regression models with associated errors

ABSTRACT

The purpose of this paper is to prove, under mild conditions, the asymptotic normality of the rank estimator of the slope parameter of a simple linear regression model with stationary associated errors. This result follows from a uniform linearity property for linear rank statistics that we establish under general conditions on the dependence of the errors. We prove also a tightness criterion for weighted empirical process constructed from associated triangular arrays. This criterion is needed for the proofs which are based on that of Koul [Behavior of robust estimators in the regression model with dependent errors. Ann Stat. 1977;5(4):681–699] and of Louhichi [Louhichi S. Weak convergence for empirical processes of associated sequences. Ann Inst Henri Poincaré Probabilités Statist. 2000;36(5):547–567].     

Synergy evaluation of non-normalizable dose–response data: Generalization of combination index for the linear effect of drugs

The study of drug synergy plays a prominent role in the search for drug combinations with beneficial interactions. Firstly, in this process, the drug-effect response of individual parts and the mixture needs to be derived. This function is usually well described by Hill (or other logistic or sigmoid) curve. Due to its boundedness, it allows the measured data to be normalized. The normalized data can then be processed by interaction analysis using the Loewe, Bliss, or other models to evaluate possible synergy or antagonism of two or more drugs. However, sometimes, the drug-effect responses observed in pharmaceutical research do not appear to be bounded. Theoretically, the drug-effect curve cannot grow to infinity, but it may be impossible to determine its upper bound within the observed region. In this case, standard models cannot be used, since they assume that data are normalized. The approach of this article bypasses the need to normalize the data, allowing its broader application and usefulness in finding potential synergies in pharmaceutical research.     

Impact of CO<Subscript>2</Subscript> Emissions Reductions on Firms’ Finance in an Emerging Economy: The Case of the Czech Republic

This paper investigates the relationship between economic and environmental performance with focus on firms in an emerging economy, the Czech Republic, and their CO₂ emission reductions. We discuss whether the hypotheses tested for local pollutants that firms emit and firms’ finances are relevant for CO₂ emissions. We test the hypotheses on a sample of Czech firms included in the first phase of European Union Emissions Trading Scheme (EU ETS). We observe that introduction of EU ETS did not encourage significant investments in CO₂ emissions reduction. Importantly, the results show that the firms that did invest in CO₂ reductions experienced a negative impact on their finance. We argue that this is explained by the drop in the price of allowances on the carbon market in 2006 which resulted in firms receiving less revenue from saved allowances than they had expected.     

Gender differences in young adults’ inclination to sacrifice career opportunities in the future for family reasons: comparative study with university students from Nairobi,Madrid, and Reykjavik

This article addresses the question of to what extent young people show an inclination to accept some sacrifice in their career progression in the future in order to reach a better work–family balance. Data come from a survey conducted among a sample of 2383 university students who attended three universities: University of Nairobi, University of Iceland, and Complutense University of Madrid. After building a set of indicators about career and family involvement aspirations of respondents, and after conducting a statistical and regression analysis, this research shows that young women (on average) still have a greater predisposition than young men to make sacrifices in the future in their working careers in order to achieve a better work–family balance. Moreover, having a high degree of leadership aspirations and belonging to an egalitarian household tend to reduce the inclination to sacrifice career opportunities, whereas having a high inclination to be involved in childcare in the future and having the perception of a future work–family conflict tend to increase it. Gender attitudes have a differential effect on female and male students: having traditional gender attitudes tends to increase the inclination to sacrifice career opportunities in the case of female students and reduce it in the case of male students.     

Family system of help and aid against the background of social transformation

This paper sums up the results of empirical research into the intergenerational solidarity in Czech families which should help to answer the question whether the family or the kinship system can discharge their self-supportive potential adequately under the pressures of the transformation processes during the 1990s. It also describes the macro-social framework, i.e. the socio-political, economic and demographic context that influences the quantitative and qualitative aspects of kinship assistance. Overall, the paper provides a general picture of informal support systems as the basis for the specific recommendation for practical social work.     

Radon as a Tracer of Lung Changes Induced by Smoking

After smoking, exposure to radon and its progeny is the second leading cause of lung cancer. The probability of inducing lung carcinomas by inhaled radon progeny depends on the deposited radiation dose, and is significantly affected by physiological and morphometric changes induced by smoking. Due to irritation of the airways, the inhalation of cigarette smoke leads to the hyperproduction of mucus. Two concurrent processes occur: on one hand, increased production of mucus protects the target cells against radiation damage; on the other hand, in the case of long-term smokers, a chronic lung obstruction develops, causing an increase in the radiation dose to the lungs. Depending on the duration and intensity of smoking, these processes contribute to the final radiation dose with different weights. The primary objective of this study was to investigate to what extent these smoke-induced changes can modify the resulting absorbed dose of inhaled radon progeny relative to healthy nonsmokers. Since the bronchial dose depends on the degree of lung tissue damage, we have used this dose as a tool for detecting the effects of smoking on the lung epithelium. In other words, the biological effect of radon served as a tracer of changes induced by smoking.     

A two-phase algorithm for bin stretching with stretching factor 1.5

Online Bin Stretching is a semi-online variant of bin packing in which the algorithm has to use the same number of bins as an optimal packing, but is allowed to slightly overpack the bins. The goal is to minimize the amount of overpacking, i.e., the maximum size packed into any bin.We give an algorithm for Online Bin Stretching with a stretching factor of 1.5 for any number of bins. We build on previous algorithms and use a two-phase approach. However, our analysis is technically more complicated and uses amortization over the bins with the help of two weight functions.     

A tighter insertion-based approximation of the crossing number

Let G be a planar graph and F a set of additional edges not yet in G. The multiple edge insertion problem (MEI) asks for a drawing of \(G+F\) with the minimum number of pairwise edge crossings, such that the subdrawing of G is plane. Finding an exact solution to MEI is NP-hard for general F. We present the first polynomial time algorithm for MEI that achieves an additive approximation guarantee—depending only on the size of F and the maximum degree of G, in the case of connected G. Our algorithm seems to be the first directly implementable one in that realm, too, next to the single edge insertion. It is also known that an (even approximate) solution to the MEI problem would approximate the crossing number of the F-almost-planar graph \(G+F\), while computing the crossing number of \(G+F\) exactly is NP-hard already when \(|F|=1\). Hence our algorithm induces new, improved approximation bounds for the crossing number problem of F-almost-planar graphs, achieving constant-factor approximation for the large class of such graphs of bounded degrees and bounded size of F.