Espagne : les feux de forêt en 1999.

Le pourcentage de surface forestière nationale brûlée n'a atteint que 0,3%, ce qui représente le chiffre le plus bas de la zone de risque du bassin méditerranéen

Quantum Nanomagnetism

In this paper we discuss some of our most important results in quantum nanomagnets in the last twenty years. We start with the tunnelling of the magnetic moment in single domain particles, then we will move to molecular magnets to explain both resonant spin tunnelling and quantum magnetic deflagration and we will finish discussing the quantum phenomena recently observed in vortices of two dimensional disks and in type I superconductors. Probably the most important question to answer in the cases presented in this paper refers to the possibility to detect both coherent phonons and photons from the demagnetization process of molecular magnets as well as the fact to go deeper in the quantum phenomena observed in vortices of two dimensional disks and in type I superconductors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3535

Impact of the Two-Slope Path Loss Model in the Service Quality of 4G and 5G Small Cells

Together with cell-free networks, small cells enable ultra-dense networks in 5G. Although small cell networks will be part of heterogeneous networks, the comparison of service quality of urban micro (UMi) small cells between 4G and 5G second phase scenarios is still of great relevance. Usage of video (VID), is considered. Quality of service (QoS) is determined by considering a packet loss ratio (PLR) lower than 2%, for different sub-6 GHz frequency bands. The aim is to compare the system capacity between 4G and 5G enhanced mobile broadband in different bands. ITU defined two UMi cell scenarios for urban micro cells that consider two-slope (TS) path loss models (PLMs). In this work, we have included TS-PLMs into the LTESim (4G) and 5G-air-simulator. The service quality and system performance bands have then been evaluated. Results shows that it is possible to support more user terminals (UTs) with 5G (up to 26 UTs) than with 4G (10 UTs only). When PLR<2%, the average delay decreases and the average goodput increases when 5G is considered. The maximum average goodput also increases with 5G.info:eu-repo/semantics/acceptedVersio

An Extensive Study on the Performance Evaluation and Scheduling of HeNBs

Since the dawn of mobile communication systems, reducing the cell size has been one option to increase the signal-to-interference-plus-noise ratio (SINR) in both links. The impact of this reduction can be perfectly understood by considering Shannon’s law. This work studies in detail the performance of Home eNBs (HeNBs), nodes with a smaller coverage area. After a detailed theoretical study of the SINR, a simulation approach is used to extract performance results in small cell indoor scenarios. Results corresponding to the goodput, delay and packet loss ratio are analyzed. Based on an improved version of LTE-Sim, the proportional fair, frame level scheduler (FLS) and exponential rule are tested in an indoor environment. With the saturation conditions taken into consideration, the FLS performs better than the other schedulers. This work shows that with the considered applications, it is possible to achieve a reduction in the transmitter power of HeNBs without compromising the small cell network performance.This work was supported by Foundation for Science and Technology/Ministry of Science, Technology and Higher Education (FCT/MCTES) through national funds and, when applicable, co-funded EU funds under the project UIDB/50008/2020, COST CA 15104 Inclusive Radio Communication Networks for 5G and Beyond (IRACON), Optical Radio Convergence Infrastructure for Communications and Power Delivering (ORCIP, 22141-01/SAICT/2016), TeamUp5G and CONQUEST (CMU/ECE/0030/2017). The TeamUp5G project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie project number 813391.info:eu-repo/semantics/publishedVersio

Characterization of single-molecule pentanedithiol junctions by inelastic electron tunneling spectroscopy and first-principles calculations

We study pentanedithiol molecular junctions formed by means of the break-junction technique with a scanning tunneling microscope at low temperatures. Using inelastic electron tunneling spectroscopy and first-principles calculations, the response of the junction to elastic deformation is examined. We show that this procedure makes a detailed characterization of the molecular junction possible. In particular, our results indicate that tunneling takes place through just a single molecule.Comment: 5 pages, 4 figures (accepted in Phys. Rev. B

Are Conditional Cash Transfers Effective in Urban Areas? Evidence from Mexico

Conditional cash transfer (CCT) programs have spread worldwide as a new form of social assistance for the poor. Previous evaluations of CCT programs focus mainly on rural settings, and little is known about their effects in urban areas. This paper studies the short-term (one and two-year) effects of the Mexican Oportunidades CCT program on urban children/youth. The program provides financial incentives for children/youth to attend school and for family members to visit health clinics. To participate, families had to sign up for the program and be deemed eligible. Difference-in-difference propensity score matching estimates indicate that the program is successful in increasing school enrollment, schooling attainment and time devoted to homework and in decreasing working rates of boys.conditional cash transfer programs, matching estimators, program evaluation