Regression-based age estimation of a stratigraphic isotope sequence in Switzerland

Multi-proxy data such as pollen percentages, aquatic biota, and stable isotope ratios in lake sediments in conjunction with climate transfer functions can be used to reconstruct past climate. This has been the subject of some recent projects. Often, stable-isotope ratios of oxygen are used as an independent proxy for climate. Past climate so reconstructed can in turn be used to assess the response of past vegetation to climatic oscillations, for instance near the epoch boundaries. One important intermediate step is to establish the age of the stratigraphic sequence. Strong similarities between the δ 18O records from European lake sediments and the Greenland ice cores are of interest. The Greenland ice-core project (GRIP) provided δ 18O data that were dated using an ice-flow model. Although the physical laws behind the isotope series from ice and lake sediment are different, statistical methods can be used to match the two series. In this paper, a regression-based approach is suggested for series matching. The method is illustrated by analyzing a series of δ 18O records covering the Late-glacial interstadial (ca. 15,000-13,000 years b.p. [1950]) from Gerzensee, Switzerland. Regression methods for age-depth modelling have also been recommended by other authors. Such an approach leads to reproducible and statistically founded age estimates and can easily be updated to include new data and information as needed. In this paper, the modelling step is preceded by identifying comparable sub-sections in the two isotope series by empirically matching the local minima and maxima in the smoothed isotope values; regression models are then used locally for each sub-section. This accommodates for local differences in the parameters. Variations in the final age estimates caused by different choices of the smoothing (bandwidth) parameters used in the intermediate nonparametric smoothing step are also taken into account in this algorith

On Estimating the Cumulant Generating Function of Linear Processes

We compare two estimates of the cumulant generating function of a stationary linear process. The first estimate is based on the empirical moment generating function. The second estimate uses the linear representation of the process and the empirical moment generating function of the innovations. Asymptotic expressions for the mean square errors are derived under short- and long-range dependence. For long-memory processes, the estimate based on the linear representation turns out to have a better rate of convergence. Thus, exploiting the linear structure of the process leads to an infinite gain in asymptotic efficienc

Assessing Psychological Effects of Cyberbullying on the Adolescents of a Cosmopolitan City

The popularity of computer-mediated communication and cyber technology has created many new vices in society that obstruct the development of adolescents. One such vice is cyberbullying, which is an insidious and covert form of bullying. The present paper opts to scrutinise cyberbullying's psychological effects on the victim teenagers of minority communities of a cosmopolitan city. Confirmatory factor analysis, for testing the Psychological Effect of Cyberbullying Scale (PECS) comprising 24 direct item pool, was employed to unfold Mild Psychological Effect Scale (MPES) and Intense Psychological Effect Scale (IPES). Cross validating the initial factor structure was conducted with the help of developing standardised coefficient for the two factor model for PECS. Cronbach's alpha reliability coefficient values are above 0.09 for the items of both the Mild Psychological Effect Scale (MPES) and Intense Psychological Effect Scale (IPES). Based on purposive sampling, the study found that all the items taken for conducting the survey are highly co-related to the psychological impact of the victim teens of the minority community of the cosmopolitan city. So the PECS developed for measuring the effect has significance. Study results also indicate that the PECS can serve as a valuable tool for measuring the mental impact of cyberbullying among teenagers

Trends in the prevalence of diarrheagenic Escherichia coli among hospitalized diarrheal patients in Kolkata, India

BACKGROUND:　 To analyse the trends in the prevalence of different pathogroups of diarrheagenic Escherichia coli (DEC) among hospitalized acute diarrheal patients.　 METHODOLOGY/PRINCIPAL FINDINGS:　 From the active surveillance of diarrheal disease at the Infectious Diseases Hospital, Kolkata, 3826 stool specimens collected during 2008-2011 were screened for DEC and other enteric pathogens. PCR was used in the detection of enterotoxigenic, enteropathogenic and enteroaggregative E. coli and 10 major colonization factor antigens (CFs) of enterotoxigenic E. coli. The relationship between DEC infected patient's age group and clinical symptoms were also investigated. Multiplex PCR assay showed that the prevalence of EAEC was most common (5.7%) followed by ETEC (4.2%) and EPEC (1.8%). In diarrheal children >2 year of age, EAEC and EPEC were detected significantly (p = 0.000 and 0.007, respectively). In children >2 to 5 and >5 to 14 years, ETEC was significantly associated with diarrhea (p = 0.000 each). EAEC was significantly associated with diarrheal patients with age groups >14 to 30 and >30 to 50 years (p = 0.001, and p = 0.009, respectively). Clinical symptoms such as vomiting, abdominal pain, watery diarrhea, were recorded in patients infected with ETEC. Dehydration status was severe among patients infected by ST-ETEC (19%) and EPEC (15%). CS6 was frequently detected (37%) among ETEC.　 CONCLUSIONS/SIGNIFICANCE:　 Hospital based surveillance reviled that specific pathogroups of DEC are important to certain age groups and among ETEC, CS6 was predominant

Vibrio fluvialis in Patients with Diarrhea, Kolkata, India

We identified 131 strains of Vibrio fluvialis among 400 nonagglutinating Vibrio spp. isolated from patients with diarrhea in Kolkata, India. For 43 patients, V. fluvialis was the sole pathogen identified. Most strains harbored genes encoding hemolysin and metalloprotease; this finding may contribute to understanding of the pathogenicity of V. fluvialis

Estimating the Mean Direction of Strongly Dependent Circular Time Series

A class of circular processes based on Gaussian subordination is introduced. This allows for flexible modelling of directional time series with long‐range dependence. Based on limit theorems for subordinated processes and consistent estimation of nuisance parameters, asymptotic confidence intervals for the mean direction are derived. Extensions to cases where the direction depends on explanatory variables are also considered. Simulations and a data example illustrate the proposed method.publishe

International Trade, Immigration and Human Capital: A Bayesian Efficiency Analysis of the 50 U.S. States

Abstract We study the growth effects of two cross-border activities, flow of goods and flows of labor on U.S. state-level productivity. Using a Bayesian approach we estimate a stochastic frontier model to measure the efficiency externalities of state-level exports and immigration to each of the 50 U.S. states. Our results show that state productivity is affected negatively by state exports and immigration. However, when state exports and immigration interact together it raises state efficiency and are complements at the regional level. Incorporating human capital into the model shows that both interactions of immigrants with accumulated human capital at the state level as well as human capital embodied in immigrants entering each state improves state efficiency

Do Refugee-Immigrants Affect International Trade? Evidence from the World\u27s Largest Refugee Case

This paper investigates the impact of refugees on a developing host country\u27s bilateral trade with the source country using a Vector Error Correction model and Granger causality tests. Using the largest case of refugee settlements in the world, we look at how refugees moving over several decades from Afghanistan to Pakistan have affected bilateral trade both directly and indirectly. We find that changes in Afghani refugees do not Granger cause movements in bilateral trade between Afghanistan and Pakistan but foreign aid to Afghanistan does Granger cause trade between the two countries

Firm Employment Growth, R&D Expenditures and Exports

This paper studies firms’ decisions to export and invest in R&D and their effects on employment growth and labor flows for a sample of Italian SMEs operating in the manufacturing industry. After accounting for the under-reporting of R&D in SMEs, our quantile regressions reveal that (i) R&D is associated with higher employment growth rates, higher hiring rates and lower separation rates; (ii) R&D-induced exports are negatively related to employment growth and accessions and positively related to separations; and (iii) pure exports are not a driver of employment growth and labor flows