Analyzing supply response of fruit tree products in Tunisia: The case of peaches

In Tunisia, peaches have a significant place in the fruit tree sector. Planted areas have been expanding ever since the eighties as a result of irrigation water extension and the use of better yielding varieties. These factors resulted in high production levels and fruit exports thereof. However, important seasonal and annual variation of fruit supplies continues to characterize prices at both wholesale and consumption levels. To study the response of peach production an econometric model was developed. Modelling was carried out in two stages. First area variation was explained through new plantings and removals and second yield variation was analyzed. The methodological approach followed takes into account the characteristics and specificities related to perennial crops. Weak response of supply to variations in expected prices was obtained. Supply price elasticity was estimated about 0.13 suggesting a high degree of inelasticity.Supply response, modeling, price expectations, peaches, Demand and Price Analysis,

Jump Dynamics And Volatility Components For OECD Stock Returns

The paper applies Markov Regime Switching Model (MRSM) to investigate the volatility behaviour of twelve OECD stock markets (U.S.A, France, Ireland, Netherlands, Spain, Denmark, Norway, Sweden, Switzerland, UK, Australia and Japan) for the period 2004-2010. The results highlight two different regimes: the first regime consist of low mean high volatility whereas the second regime is categorized by high mean low volatility. We conclude that the periods of high volatility are generally synchronous to several economic and/or political events in all the developed markets during the period under investigation

Laser à fibre dopée erbium à 1600 nm. Fonctionnement continu et verrouille en phase

L\u27objectif de cet article est de démontrer la possibilité de faire osciller à 1.6 µm un amplificateur à fibre double gaine dopée erbium opérant dans la bande C, en ajustant les pertes intra-cavité. Deux configurations de cavité ont été utilisées, une cavité en anneau et une cavité en forme de huit. Dans les deux cas, il est possible d\u27obtenir l\u27oscillation à 1.6 µm en continu ou bien en impulsions ultra-courtes

High power L-band mode-locked fiber laser based on topological insulator saturable absorber

We demonstrate a passive mode-locked Er:Yb doped doubleclad fiber laser using a microfiber-based topological insulator (Bi2Se3) saturable absorber (TISA). By optimizing the cavity loss and output coupling ratio, the mode-locked fiber laser can operate in L-band with high average output power. With the highest pump power of 5 W, 91st harmonic mode locking of soliton bunches with average output power of 308 mW was obtained. This is the first report that the TISA based erbium-doped fiber laser operating above 1.6 μm and is also the highest output power yet reported in TISA based passive mode-locked fiber laser

1.6 μm emission based on linear loss control in a Er:Yb doped double-clad fiber laser

Based on the control of the linear losses of the cavity, we demonstrate the possibility to achieve filterless laser emission above 1.6 μm, from a C-band double-clad Er:Yb doped fiber amplifier. The concept is validated in both continuous wave and mode-locked regimes, using a figure-of-eight geometry. A unidirectional ring cavity is also tested in the continuous regime. Spectral properties of laser emissions are characterized as a function of the intracavity linear losses

Evaluation capacity building in response to the agricultural research impact agenda: Emerging insights from Ireland, Catalonia (Spain), New Zealand, and Uruguay

Performance-based funding and calls for public-funded science to demonstrate societal impact are encouraging public research organisations to evaluate impact, the so-called impact agenda. This paper explores evaluation methods of four fully or partially public-funded agricultural research organisations and how they are building evaluative capacity to respond to the impact agenda. Drawing on cross- organisational comparison of the readiness of each organisation to implement evaluation, the implications for improving evaluative capacity building (ECB) are discussed. This study extends the current literature on ECB, as very little has focussed on research organisations in general, and particularly agricultural research.Postprint (author's final draft

A Numerical-Analytical Hybrid Approach for the Identification of SDM Solar Cell Unknown Parameters

Appropriate modeling and accurate parameter identification of solar cells are crucial in the optimization of photovoltaic (PV) systems. The single-diode model (SDM), consisting of an ideal current source, an ideal diode, a shunt resistor and a series resistor, is widely used to simulate the behavior of PV cells/panels. In this article, a hybrid approach for identification of solar cell SDM parameters is presented. This approach uses the inverse of the slope of the I-V curve under short-circuit and open-circuit conditions and combines numerical and analytical solutions. Indeed, knowing that numerical methods require appropriate initial values, the main idea of the proposed approach is to provide these solutions by analytical methods. The comparison of obtained results with experimental ones, based on manufacturer’s datasheet, proves that the algorithm thus obtained requires less information from the manufacturer and improves significantly the parameter identification accuracy