Open source as a signalling device : an economic analysis

Open source projects produce goods or standards that do not allow for the appropriation of private returns by those who contribute to their production. In this paper we analyze why programmers will nevertheless invest their time and effort to code open source software. We argue that the particular way in which open source projects are managed and especially how contributions are attributed to individual agents, allows the best programmers to create a signal that more mediocre programmers cannot achieve. Through setting themselves apart they can turn this signal into monetary rewards that correspond to their superior capabilities. With this incentive they will forgo the immediate rewards they could earn in software companies producing proprietary software by restricting the access to the source code of their product. Whenever institutional arrangements are in place that enable the acquisition of such a signal and the subsequent substitution into monetary rewards, the contribution to open source projects and the resulting public good is a feasible outcome that can be explained by standard economic theory

The ant or the grasshopper? The long-term consequences of Unilateral Divorce Laws on savings of European households

Unilateral Divorce Laws (UDLs) allow people to obtain divorce without the consent of their spouse. Using the staggered introduction of UDLs across European countries, we show that households exposed to UDLs for a longer period of time accumulate more savings. This effect holds for both financial and total wealth and is stronger at higher quantiles of the wealth distribution. Consistent with a precautionary motive for savings, we also find that exposure to UDLs increases female labour supply, numeracy, trust in others and dispositional optimism

Fractional calculus and continuous-time finance II: the waiting-time distribution

We complement the theory of tick-by-tick dynamics of financial markets based on a Continuous-Time Random Walk (CTRW) model recently proposed by Scalas et al., and we point out its consistency with the behaviour observed in the waiting-time distribution for BUND future prices traded at LIFFE, London.Comment: Revised version, 17 pages, 4 figures. Physica A, Vol. 287, No 3-4, 468--481 (2000). Proceedings of the International Workshop on "Economic Dynamics from the Physics Point of View", Bad-Honnef (Germany), 27-30 March 200

On the origin and elimination of cross coupling between tunneling current and excitation in scanning probe experiments that utilize the qPlus sensor

The qPlus sensor allows simultaneous measurements of scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Its design for use in frequency modulation AFM (FM-AFM) involves separate electrodes, applied on an oscillating quartz cantilever, for the detection of an electronic tunneling current and the deflection signal. Cable resistance and capacities in the electronic setup can induce cross talk phenomena. We report a tunneling current-induced cross coupling observed in a combined STM/AFM setup which uses the qPlus sensor. This cross coupling can induce a positive or negative change of the amplitude excitation signal, thus acting as an apparent dissipation or drive. The experimental data is explained well by tunneling current-induced fluctuations of the electric potential on the sensor electrodes

Quantum Breathing of an Impurity in a One-dimensional Bath of Interacting Bosons

By means of time-dependent density-matrix renormalization-group (TDMRG) we are able to follow the real-time dynamics of a single impurity embedded in a one-dimensional bath of interacting bosons. We focus on the impurity breathing mode, which is found to be well-described by a single oscillation frequency and a damping rate. If the impurity is very weakly coupled to the bath, a Luttinger-liquid description is valid and the impurity suffers an Abraham-Lorentz radiation-reaction friction. For a large portion of the explored parameter space, the TDMRG results fall well beyond the Luttinger-liquid paradigm.Comment: 10 pages, 7 figures, main text and supplementary material merged in a single PRB style documen

Revealing a spatially inhomogeneous broadening effect in artificial quantum structures caused by electron-adsorbate scattering

What defines the lifetime of electronic states in artificial quantum structures? We measured the spectral widths of resonant eigenstates in a circular, CO-based quantum corral on a Cu(111) surface and found that the widths are related to the size of the corral and that the line shape is essentially Gaussian. A model linking the energy dependence with the movement of single surface electrons shows that the observed behavior is consistent with lifetime limitations due to interaction with the corral walls

Determinants of Mobile Broadband Affordability: A Cross-National Comparison

There is little understanding of what determines mobile broadband affordability in different countries. We address this problem by exploring to what extent policy, regulation, government, and governance affect mobile broadband affordability. Our results show that when controlling for wealth, education and other factors, competition to provide mobile services, financial investment in information and communication technologies (ICTs), and income inequality are all important variables in determining mobile broadband affordability. Our findings related to financial investment suggest that service providers and other stakeholders are still recouping the cost of deploying the infrastructure necessary to provide mobile services, and have not yet achieved the economy of scale required for the price of mobile broadband to begin to fall. Although policy initiatives and income inequality are important determinants of mobile broadband affordability, we find no evidence that political structure and processes (e.g., the level of democracy), telecommunications regulation, or public-sector governance matter

Volatile organic compounds in aquatic ecosystems – Detection, origin, significance and applications

Volatile organic compounds (VOCs) include a broad range of compounds. Their production influences a large number of processes, having direct and secondary effects on different fields, such as climate change, economy and ecology. Although our planet is primarily covered with water (~70% of the globe surface), the information on aquatic VOCs, compared to the data available for the terrestrial environments, is still limited. Regardless of the difficulty in collecting and analysing data, because of their extreme complexity, diversification and important spatial-temporal emission variation, it was demonstrated that aquatic organisms are able to produce a variety of bioactive compounds. This production happens in response to abiotic and biotic stresses, evidencing the fundamental role of these metabolites, both in terms of composition and amount, in providing important ecological information and possible non-invasive tools to monitor different biological systems. The study of these compounds is an important and productive task with possible and interesting impacts in future practical applications in different fields. This review aims to summarize the knowledge on the aquatic VOCs, the recent advances in understanding their diverse roles and ecological impacts, the generally used methodology for their sampling and analysis, and their enormous potential as non-invasive, non-destructive and financeable affordable real-time biomonitoring tool, both in natural habitats and in controlled industrial situations. Finally, the possible future technical applications, highlighting their economic and social potential, such as the possibility to use VOCs as valuable alternative source of chemicals and as biocontrol and bioregulation agents, are emphasized.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

110th Anniversary: Syngas production enhancement using calcium and potassium impregnated chars

International audienceSyngas production enhancement via catalytic methane cracking onto metal-loaded chars, with a specific focus on the activity of two inherent alkali and alkaline earth metals (AAEMs), Ca and K, was investigated. Chars produced from the gasification of poplar wood pellets were heated to 700°C in inert atmosphere and then tested as catalysts for methane cracking at 700°C. Methane is one of the most abundant biomass gasification by-product. The cracking of this component is relevant in increasing the syngas production and yield. The syngas production was increased by a factor 1.9 to 2.7 using metal-loaded chars. Results were explained by the catalytic effect of AAEMs on both the desorption of oxygenated functional groups and on the catalytic methane cracking. AAEMs promoted methane molecules combination with the active sites such as oxygenated groups available at the surface of the chars enhancing both H2 and CO production. It was observed that potassium loaded char (K-char) showed the best performance. The calcium-loaded char (Ca-char) was less efficient, due to a higher amount of silicon which interacted with calcium to form silicates. No synergetic effect was observed on the syngas production with the Ca+K_char