Potentialités de l’écotourisme et géotourisme aux provinces de Tantan, Tarfaya et Layoune (Sahara Atlantique marocain)

Tantan, Tarfaya and Laayoune provinces, which belong to the Moroccan Atlantic Sahara, are characterized by exceptional geo and ecotourism potentials. In this context, singing dunes, sand rivers and the presence of several wadis mouth’s in such desert environment could constitute a locomotive for the development of green and geological tourism. Indeed, the studied region presents Eco and Geo-tourism potentials, combining ecological sites classified by the RAMSAR convention as the Khnifis lagoon, the wadis mouth’s including the longest river in Morocco (Oued Draa) with its new national park. Rivers of sand with multitudes sand colours, singing dunes, virgin beaches and sebkhas with the lowest point in Morocco, the sebkha of Tah with an altitude of -55 m adsl

Drainage, Rebound and Oscillation of a Meniscus in a Tube

In this paper, the drainage and subsequent rebound of a liquid column in a cylindrical tube is examined experimentally and theoretically. When liquid is drawn up into a capillary and then released under gravity, inertia allows the meniscus to overshoot the equilibrium capillary rise height. The meniscus then rebounds up the tube, again overshooting the equilibrium height and undergoes oscillation. By varying both the immersion depth and radius of the tube, one can observe rich dynamical behavior, with the most dramatic being the formation of a fast liquid jet, barely visible to the naked eye but easily captured with high-speed video. In addition to the flow separation caused by the sudden expansion at the end of the tube, this jet serves as a mechanism of energy dissipation. Some qualitative differences between the works of Quere et al. [“Rebounds in a capillary tube,” Langmuir 15, 3679–3682 (1999)] and Lorenceau et al. [“Gravitational oscillations of a liquid column in a pipe,” Phys. Fluids 14(6), 1985–1992 (2002)] and the present experiment are observed and discussed. A critical condition for oscillatory behavior is derived theoretically and matches well with the experimental observation. Once in the oscillatory regime, both the maximum depth below and the maximum rebound height above the equilibrium level are investigated by performing a systematic sweep through the relevant parameter space, incorporating the initial meniscus height, immersion depth, tube radius, and fluid properties. Lastly, the characteristic period of oscillation, tp, is assessed and found to be largely independent of fluid viscosity, and could be reasonably well-collapsed by a single curve whereby tp~√(hi), where hi is the tube immersion depth

Population Structure and Diversity in European Honey Bees (Apis mellifera L.)-An Empirical Comparison of Pool and Individual Whole-Genome Sequencing

Background: Whole-genome sequencing has become routine for population genetic studies. Sequencing of individuals provides maximal data but is rather expensive and fewer samples can be studied. In contrast, sequencing a pool of samples (pool-seq) can provide sufficient data, while presenting less of an economic challenge. Few studies have compared the two approaches to infer population genetic structure and diversity in real datasets. Here, we apply individual sequencing (ind-seq) and pool-seq to the study of Western honey bees (Apis mellifera). Methods: We collected honey bee workers that belonged to 14 populations, including 13 subspecies, totaling 1347 colonies, who were individually (139 individuals) and pool-sequenced (14 pools). We compared allele frequencies, genetic diversity estimates, and population structure as inferred by the two approaches. Results: Pool-seq and ind-seq revealed near identical population structure and genetic diversities, albeit at different costs. While pool-seq provides genome-wide polymorphism data at considerably lower costs, ind-seq can provide additional information, including the identification of population substructures, hybridization, or individual outliers. Conclusions: If costs are not the limiting factor, we recommend using ind-seq, as population genetic structure can be inferred similarly well, with the advantage gained from individual genetic information. Not least, it also significantly reduces the effort required for the collection of numerous samples and their further processing in the laboratory.This work was supported by National Natural Science Foundation of China (Grant No. 31902219) and Modern Agro-industry Technology Research System (Grant No. CARDS-45-KXJ1). The SmartBees project was funded by the European Commission under its FP7 KBBE programme (2013.1.3-02, SmartBees Grant Agreement number 613960). MP and J.L were supported by the Applied Genomics and Bioinformatics research group (IT1233-19) funded by the Basque Government grant IT1233-19. Additionally, JL was funded by the grant PRE_2017_2_0169 from the Department of Education of the Basque Government

A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

Opportunities for Gas-Phase Science at Short-Wavelength Free-Electron Lasers with Undulator-Based Polarization Control

Free-electron lasers (FELs) are the world's most brilliant light sources with rapidly evolving technological capabilities in terms of ultrabright and ultrashort pulses over a large range of accessible photon energies. Their revolutionary and innovative developments have opened new fields of science regarding nonlinear light-matter interaction, the investigation of ultrafast processes from specific observer sites, and approaches to imaging matter with atomic resolution. A core aspect of FEL science is the study of isolated and prototypical systems in the gas phase with the possibility of addressing well-defined electronic transitions or particular atomic sites in molecules. Notably for polarization-controlled short-wavelength FELs, the gas phase offers new avenues for investigations of nonlinear and ultrafast phenomena in spin orientated systems, for decoding the function of the chiral building blocks of life as well as steering reactions and particle emission dynamics in otherwise inaccessible ways. This roadmap comprises descriptions of technological capabilities of facilities worldwide, innovative diagnostics and instrumentation, as well as recent scientific highlights, novel methodology and mathematical modeling. The experimental and theoretical landscape of using polarization controllable FELs for dichroic light-matter interaction in the gas phase will be discussed and comprehensively outlined to stimulate and strengthen global collaborative efforts of all disciplines

Microfabricated Reference Electrodes and their Biosensing Applications

Over the past two decades, there has been an increasing trend towards miniaturization of both biological and chemical sensors and their integration with miniaturized sample pre-processing and analysis systems. These miniaturized lab-on-chip devices have several functional advantages including low cost, their ability to analyze smaller samples, faster analysis time, suitability for automation, and increased reliability and repeatability. Electrical based sensing methods that transduce biological or chemical signals into the electrical domain are a dominant part of the lab-on-chip devices. A vital part of any electrochemical sensing system is the reference electrode, which is a probe that is capable of measuring the potential on the solution side of an electrochemical interface. Research on miniaturization of this crucial component and analysis of the parameters that affect its performance, stability and lifetime, is sparse. In this paper, we present the basic electrochemistry and thermodynamics of these reference electrodes and illustrate the uses of reference electrodes in electrochemical and biological measurements. Different electrochemical systems that are used as reference electrodes will be presented, and an overview of some contemporary advances in electrode miniaturization and their performance will be provided

The country of brand communication in the retail setting: An analysis of Italian products in China

The aim of this paper is to investigate the role of country of brand (COB) communication within the retail environment of emerging markets. Drawing from the literature on store image, we developed a framework to analyse static and dynamic elements of COB communication. By adopting an inductive approach, we analysed COB use in a sample of 20 stores of Italian fashion brands in China using the mystery shopping technique. Given the increasing growth of e-retailing in China, the in-store observation is complemented by an analysis of the use of COB within the brand's local website and e-commerce page. In order to have a multi-layered representation of the phenomenon, in-depth interviews with managers of Italian firms in fashion industry are carried out. Findings confirm that retailing represents a primary communication channel for firms operating in China; however, the results of the participant observation show that COB is a cue information utilised only by a small percentage of the sample, mainly in a textual and iconic way. Managerial implications are discussed on the extent to which COB communication in store should be managed within an effective marketing strategy in line with the country and consumer characteristics in order to enhance the brand image in a growing market like China

Applications of MALDI-TOF Mass Spectrometry in Clinical Diagnostic Microbiology

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) represents one of the most accurate, reliable, and fast methods for the identification of bacterial strains from positive cultures, and therefore it has largely replaced all other previously used approaches for microbial identification. The main application of MALDI-TOF MS in clinical microbiology laboratories is the identification of bacteria from colonies recovered from solid culture media. This chapter discusses specific identification procedures that are needed for some bacteria, such as Actinomycetes and Mycobacteria. The performance of MALDI-TOF MS identification relies on the number of mass spectra that reach the quality allowing identification and the number of correct identifications. MALDI-TOF MS has also been proposed for Staphylococcus aureus strain typing or for the detection of biomarkers of the most virulent toxigenic isolates. MALDI-TOF MS could also be used for Mycobacterium