Globalisation, Agricultural Development and Rural Welfare in Transition

This paper analyzes the impact of globalisation on agriculture, development and rural welfare in transition countries. First, we present an overview of insights on how globalisation has affected agriculture and rural households’ welfare in transition countries based on existing studies. Secondly, the paper presents new empirical evidence on how specific aspects of ‘globalisation’, in particular the inflow of foreign investment and the integration in international commodity markets, have affected Polish agriculture, and more specifically small-scale dairy farms. Given the characteristics of this sector (many poor small farmers, low quality output, direct need for investment and restructuring, ...) this study yields useful insights which have wider implications.

On the total curvatures of a tame function

Given a definable function f, enough differentiable, we study the continuity of the total curvature function t --> K(t), total curvature of the level {f=t}, and the total absolute curvature function t-->|K| (t), total absolute curvature of the level {f=t}. We show they admits at most finitely many discontinuities

PACS and SPIRE range spectroscopy of cool, evolved stars

Context: At the end of their lives AGB stars are prolific producers of dust and gas. The details of this mass-loss process are still not understood very well. Herschel PACS and SPIRE spectra offer a unique way of investigating properties of AGB stars in general and the mass-loss process in particular. Methods: The HIPE software with the latest calibration is used to process the available PACS and SPIRE spectra of 40 evolved stars. The spectra are convolved with the response curves of the PACS and SPIRE bolometers and compared to the fluxes measured in imaging data of these sources. Custom software is used to identify lines in the spectra, and to determine the central wavelengths and line intensities. Standard molecular line databases are used to associate the observed lines. Because of the limited spectral resolution of the spectrometers several known lines are typically potential counterparts to any observed line. To help identifications the relative contributions in line intensity of the potential counterpart lines are listed for three characteristic temperatures based on LTE calculations and assuming optically thin emission. Result: The following data products are released: the reduced spectra, the lines that are measured in the spectra with wavelength, intensity, potential identifications, and the continuum spectra, i.e. the full spectra with all identified lines removed. As simple examples of how this data can be used in future studies we have fitted the continuum spectra with three power laws and find that the few OH/IR stars seem to have significantly steeper slopes than the other oxygen- and carbon-rich objects in the sample. As another example we constructed rotational diagrams for CO and fitted a two-component model to derive rotational temperatures.Comment: A&A accepte

Hierarchical Bayesian inference of the Initial Mass Function in Composite Stellar Populations

The initial mass function (IMF) is a key ingredient in many studies of galaxy formation and evolution. Although the IMF is often assumed to be universal, there is continuing evidence that it is not universal. Spectroscopic studies that derive the IMF of the unresolved stellar populations of a galaxy often assume that this spectrum can be described by a single stellar population (SSP). To alleviate these limitations, in this paper we have developed a unique hierarchical Bayesian framework for modelling composite stellar populations (CSPs). Within this framework we use a parameterized IMF prior to regulate a direct inference of the IMF. We use this new framework to determine the number of SSPs that is required to fit a set of realistic CSP mock spectra. The CSP mock spectra that we use are based on semi-analytic models and have an IMF that varies as a function of stellar velocity dispersion of the galaxy. Our results suggest that using a single SSP biases the determination of the IMF slope to a higher value than the true slope, although the trend with stellar velocity dispersion is overall recovered. If we include more SSPs in the fit, the Bayesian evidence increases significantly and the inferred IMF slopes of our mock spectra converge, within the errors, to their true values. Most of the bias is already removed by using two SSPs instead of one. We show that we can reconstruct the variable IMF of our mock spectra for signal-to-noise ratios exceeding $\sim$75.Comment: Accepted for publication in MNRAS, 16 pages, 8 figure

Scaling Ant Colony Optimization with Hierarchical Reinforcement Learning Partitioning

This paper merges hierarchical reinforcement learning (HRL) with ant colony optimization (ACO) to produce a HRL ACO algorithm capable of generating solutions for large domains. This paper describes two specific implementations of the new algorithm: the first a modification to Dietterich’s MAXQ-Q HRL algorithm, the second a hierarchical ant colony system algorithm. These implementations generate faster results, with little to no significant change in the quality of solutions for the tested problem domains. The application of ACO to the MAXQ-Q algorithm replaces the reinforcement learning, Q-learning, with the modified ant colony optimization method, Ant-Q. This algorithm, MAXQ-AntQ, converges to solutions not significantly different from MAXQ-Q in 88% of the time. This paper then transfers HRL techniques to the ACO domain and traveling salesman problem (TSP). To apply HRL to ACO, a hierarchy must be created for the TSP. A data clustering algorithm creates these subtasks, with an ACO algorithm to solve the individual and complete problems. This paper tests two clustering algorithms, k-means and G-means. The results demonstrate the algorithm with data clustering produces solutions 20 times faster with 5-10% decrease in solution quality due to the effects of clustering