Modeling heterogeneity in production models: empirical evidence from individual farming in Poland

This discussion paper deals with the estimation of a random coefficient model. The virtue of this approach is that it considers firm heterogeneity, which conventional SFA models do not. Applying the model to Polish farms, the results indicate that the conventional random and fixed effect models overestimate the inefficiency score. In addition, the reasons for inefficiency are analyzed. It is shown that despite the fragmentation of Polish agriculture, there is no evidence for scale inefficiency. Moreover, inefficiency could partly be attributed to factors, which affect the management input and requirements on farms. -- G E R M A N V E R S I O N: Das vorliegende Diskussionspapier befasst sich mit Schätzung von Random Parameter Modellen in Rahmen von Frontier Analysen. Ein wesentlicher Vorteil dieses Ansatzes liegt darin, dass er im Gegensatz zu den konventionellen SFA die Heterogenität der Untersuchungseinheiten berücksichtigt. Die empirische Analyse bezieht sich auf landwirtschaftliche Betriebe in Polen. Die Ergebnisse deuten darauf hin, dass die konventionellen Random und Fixed Effect Modelle das Niveau der Inneffizienz überschätzen. Weiterhin wurden die Ursachen der Ineffizienz untersucht. Obwohl die polnische Landwirtschaft sehr zersplittert ist, lieferten die Ergebnisse keinen statistisch gesicherten Beweis für Vorliegen von Skalenineffizienzen. Die Ursachen der Ineffizienzen liegen dagegen in Faktoren, welche auf unternehmerische Fähigkeiten des Betriebsleiters sowie betriebsorganisatorische Aspekte zurückgeführt werden können.random component model,Poland,management,SFA,Random Parameter Modell,Polen,Management

Community gardens: A natural way to wellbeing

Community gardens provide social, economic and environmental benefits to local urban communities. These include individual and collective social wellbeing, access to cheap, nutritious food and improved functioning of the local ecology. Although regarded by some as a neutral project to organise a community around, community gardening is still highly political. When planned, organised and run by local people and located centrally in the community, (particularly disadvantaged communities) these green spaces offer multiple health benefits that prevent disease and promote wellbeing, a sense of citizen control and social capital. Most indicators suggest that community gardening movement has enjoyed varied success in building healthier Sydney communities. However the intrinsic effects of this low cost, low-tech community process is hard to compare and measure. Challenges include security of tenure, establishing appropriate policy and planning guidelines with local councils and departments, ensuring active and full participation of those community groups 'at risk' and developing persuasive evaluation systems to meet these challenges. It is suggested that community gardens reflect the wider social, cultural, structural elements in the society as well as the human processes that ultimately enable or restrict healthy living

Transformation of the Navier-Stokes Equation to the Cauchy Momentum Equation Using a Novel Mathematical Notation

Abstract A transformation way of the Navier-Stokes differential equation was presented. The obtained result is the Cauchy momentum equation. The transformation was performed using a novel shorten mathematical notation presented at the beginning of the transformation

Tourist routes as a tourism product stimulating the development of tourism in Poland

Tourist routes combine cultural and natural heritage and are an inseparable element of tourism space and cultural landscape. In Poland the significance of tourist trails as a tourism product contributing to the development of the tourism economy has increased. The primary aim of this paper was to design a tourist trail combining natural and anthropogenic values. The research was conducted in the commune of Kcynia located in Kuyavian-Pomeranian voivodeship and consists of a town and 54 villages. The work makes use of the valorisation method, Wejchert’s impression curve. The results show that the Kcynia commune has sufficient natural and cultural values for developing tourism, but its tourism potential is not fully utilised in comparison with that of other communes. First of all, it lacks a well-developed tourism infrastructure. The proposed tourist routes would – in a relatively inexpensive and non-invasive way – enhance the potential and interest of the commune and improve the income of its inhabitants. In addition, it would raise interest in tourism and leisure tourism

Interplay between pairing and correlations in spin-polarized bound states

We investigate the single and multiple defects embedded in a superconducting host, studying interplay between the proximity induced pairing and interactions. We explore influence of the spin-orbit coupling on energies, polarization and spatial patterns of the bound (Yu-Shiba-Rusinov) states of magnetic impurities in 2-dimensional square lattice. We also address the peculiar bound states in the proximitized Rashba chain, resembling the Majorana quasiparticles, focusing on their magnetic polarization which has been recently reported by S. Jeon et al., [Science 358, 772 (2017)]. Finally, we study leakage of these polarized Majorana quasiparticles on the side-attached nanoscopic regions and confront them with the subgap Kondo effect near to the singlet-doublet phase transition.Comment: 10 pages, 9 figure

Civilian long endurance UAV – design challenges

This paper presents a selected aspect of design activity devoted to optimising HALE and MALE UAVs. The project is taking place at Warsaw University of Technology under the V Framework of European Union in the CAPECON project. This paper deals with wing airfoil selection, defining of the configuration layout and power unit integration. A brief overview of wing sections developed in some design centres (mainly in Israel Aircraft Industry and in Northrop Grumman) is included. Aircraft layout depends on the mission and sensor selection and is discussed using the examples of PW‐103 and PW‐114. Engine suspension and integration with aircraft is included in the analysis because if it is not properly analysed, it can lead to an excessive vibration and fatigue of the whole aircraft structure. First Published Online: 14 Oct 201