Walks confined in a quadrant are not always D-finite

We consider planar lattice walks that start from a prescribed position, take their steps in a given finite subset of Z^2, and always stay in the quadrant x >= 0, y >= 0. We first give a criterion which guarantees that the length generating function of these walks is D-finite, that is, satisfies a linear differential equation with polynomial coefficients. This criterion applies, among others, to the ordinary square lattice walks. Then, we prove that walks that start from (1,1), take their steps in {(2,-1), (-1,2)} and stay in the first quadrant have a non-D-finite generating function. Our proof relies on a functional equation satisfied by this generating function, and on elementary complex analysis.Comment: To appear in Theoret. Comput. Sci. (special issue devoted to random generation of combinatorial objects and bijective combinatorics

Structural Controls and Depositional Environments of the Glen Rose Subgroup in Pelahatchie Field in Rankin County, Mississippi

Following Lion Oil’s drilling of the Sowell #1, Lower Cretaceous step-out drilling in Pelahatchie Field has led to the establishment of Mooringsport, Paluxy, Rodessa, Sligo, and Hosston oil and gas condensate production along the flanks and crest of a salt feature within Rankin County, Mississippi. Exploration of salt features has been intermittent throughout Mississippi, but has shifted from targeting pay zones along the crests of domal and piercement salt features in the 1940s, to targeting reserves along the flanks of these features in the 1970s. The dominant structural feature in Pelahatchie Field is an elongate north-south-trending salt ridge. Results of this study suggest that combination traps predominate. The Glen Rose Subgroup in southern Rankin County transitions from upper shoreface to the south of the study area, to estuarine tidal flats in a more restrictive environment within Pelahatchie Field. The discovery of a channel within the lower Rodessa Formation records a short period of fluvial deposition. A more clear definition of paleo-depositional environments in association with structural and stratigraphic controls on production are important to the continued oil and gas exploration of salt dome plays in the Mississippi Interior Salt Basin

Modelling suspended sediment transport due to helical flow in TELEMAC-2D

Water Qualit

The Reduction Of Administrative Burdens And Its Impact On The Competitiveness Of Business

This paper focuses on the reduction of administrative burdens in Slovenia and how these actions can influence the competitiveness of business. The aim of the paper is to study and analyse the current situation in the field of Slovenian regulations and the disadvantages of the regulations for businesses, to study the possibilities for reducing administrative burdens in Slovenia and to analyse the influence of cross-border cooperation on the reduction of administrative burdens. The paper first describes the regulations and their impact on the competitiveness of business using the data from different international studies that include business environment and competitiveness and by using the results of the research carried out in Slovenia on defining the most burdensome areas of legislation. The paper continues by discussing the reduction of administrative burdens, where the Programme for the Elimination of Administrative Barriers and the Reduction of Administrative Burdens by 25% by 2012 is introduced. The third part of the paper describes the possible connection between the reduction of administrative burdens and cross-border cooperation by introducing the results of a cross-national empirical survey of the current situation and future potentials of cross-border cooperation in the Alps-Adriatic region. At the end, the paper gives some conclusions on the reduction of administrative burdens and the resulting impact on business competitiveness in Slovenia

Private And Public Sector Innovation And The Importance Of Cross-Sector Collaboration

Innovation plays a very important role in the private sector in terms of competitiveness, and is the key to success for private businesses, helping to cut costs, improve products and open new markets. Nowadays, innovation is gaining in importance in the public sector as well, as it can improve the quality of service delivery as well as reduce costs. Innovation is an important driver of economic progress and competitiveness in all economies.Collaboration between public and private entities creates better and more effective public and private services and products. Collaboration enables the participants to exchange and share knowledge, experiences, know-how and expertise. Collaboration helps to bring a broader set of skills and talents and a more responsive work culture into public sector organisations, along with innovative thinking and creativity; it also helps private companies to innovate more effectively and to achieve their concrete goals in a more efficient way.The objective of this paper is to outline the differences and similarities between private and public sector innovation in terms of definition, driving factors, barriers and measurement; the paper also aims to examine the importance of cross-sector collaboration for private and public sector innovation, and demonstrate that collaboration can improve innovation