International Interventionism 1970-1989: A Count Data Approach

Due to progress in statistical methods and improved data processing capabilities, count data modelling has become increasingly popular in the social sciences. In empirical international relations and international conflict research, however, the use of event count models has been largely restricted to the application of the simple Poisson approach so far. This article outlines the methodological weaknesses of the model and presents some improvements which are applied to the problem of international interventionism. The cross-sectional data set used covers the behaviour of states during the period from 1970 to 1989, and thus avoids some theoretical problems of the standard long-term dyadic approach. The main result of the analysis is the empirical irrelevance of idealist conceptions claiming pacifying effects of democratization or fostering of economic prosperity

Frequency and temporal effects in linear optical quantum computing

Typically linear optical quantum computing (LOQC) models assume that all input photons are completely indistinguishable. In practice there will inevitably be non-idealities associated with the photons and the experimental setup which will introduce a degree of distinguishability between photons. We consider a non-deterministic optical controlled-NOT gate, a fundamental LOQC gate, and examine the effect of temporal and spectral distinguishability on its operation. We also consider the effect of utilizing non-ideal photon counters, which have finite bandwidth and time response.Comment: 10 pages, 9 figures, replaced with published versio

Modeling photo-detectors in quantum optics

Photo-detection plays a fundamental role in experimental quantum optics and is of particular importance in the emerging field of linear optics quantum computing. Present theoretical treatment of photo-detectors is highly idealized and fails to consider many important physical effects. We present a physically motivated model for photo-detectors which accommodates for the effects of finite resolution, bandwidth and efficiency, as well as dark-counts and dead-time. We apply our model to two simple well known applications, which illustrates the significance of these characteristics.Comment: 8 pages, 7 figure

Disentangling the effects of geographic and ecological isolation on genetic differentiation

Populations can be genetically isolated both by geographic distance and by differences in their ecology or environment that decrease the rate of successful migration. Empirical studies often seek to investigate the relationship between genetic differentiation and some ecological variable(s) while accounting for geographic distance, but common approaches to this problem (such as the partial Mantel test) have a number of drawbacks. In this article, we present a Bayesian method that enables users to quantify the relative contributions of geographic distance and ecological distance to genetic differentiation between sampled populations or individuals. We model the allele frequencies in a set of populations at a set of unlinked loci as spatially correlated Gaussian processes, in which the covariance structure is a decreasing function of both geographic and ecological distance. Parameters of the model are estimated using a Markov chain Monte Carlo algorithm. We call this method Bayesian Estimation of Differentiation in Alleles by Spatial Structure and Local Ecology (BEDASSLE), and have implemented it in a user-friendly format in the statistical platform R. We demonstrate its utility with a simulation study and empirical applications to human and teosinte datasets

Do Worker Remittances Reduce Output Volatility in Developing Countries?

Remittance inflows have increased considerably in recent years and are large relative to the size of many recipient economies. The theoretical and empirical effects of remittance inflows on output growth volatility are, however, ambiguous. On the one hand, remittances have been a remarkably stable source of income, relative to other private and public flows, and they seem to be compensatory in nature, rising when the home countryÂ’s economy suffers a downturn. On the other hand, the labor supply effects induced by altruistic remittances could cause the output effects associated with technology shocks to be magnified. This paper finds robust evidence for a sample of 70 remittance-recipient countries, including 16 advanced economies and 54 developing countries that remittances have a negative effect on output growth volatility, thereby supporting the notion that remittance flows are a stabilizing influence on output.Remittances, output volatility, developing countries

All-solid-state radiometers for environmental studies to 700 GHz

We report results with an all-solid-state radiometer for measurements of the ClO molecule at 649 GHz. The project is part of a program to provide low-noise, low-weight, low-power radiometers for space operation, and special effort has been expended on the development of high-efficiency solid-state frequency multipliers and Schottky-barrier mixers with low local oscillator power requirements. The best measured system noise temperature was 1750 K with the mixer and preamplifier cooled to 77 K. The mixer diode was easily pumped into saturation, indicating that the design has excellent prospects of operating at higher frequencies - our present design goal being 1 THz. We comment on the principal design features of such systems and will report on stratospheric measurements performed with this system