Application of an improved version of the erosion potential method in alpine areas

the assessment of erosive processes is of great importance in environmental engineering, resource management and land planning. in this paper the empirical approach known as erosion Potential Method (EPM) was improved to simplify the identifi- cation of the involved parameters. in addition, EPM suitability for alpine watersheds, where the average yearly temperature may be below 0°C, was discussed. the advantages of distributed ap- proaches rather than lumped methodologies were tested. EPM was then implemented in a distributed form for a set of 31 catch- ments located in alta valtellina (northern italy) in order to cap- ture the spatial variability of the parameters and the intensity of the erosion processes. the results obtained for these catchments were positively compared to long-term sedimentation data from three reservoirs and from a turbidimetric station

An educational experience in ancient Rome to evaluate the impact of virtual reality on human learning processes

Immersive Virtual Reality technology has recently gained significant attention and is expanding its applications to various fields. It also has many advantages in education, as it allows to both simplify the explanation of complex topics through their visualization, and explore lost or unreachable environments. To evaluate the impact of immersive experiences on learning outcomes we developed an educational experience that lets users visit an ancient Roman Domus and provides information about daily life in Roman times. We designed a between-subjects data collection to investigate learning ratio, user experience, and cybersickness of participants through anonymous questionnaires. We collected 76 responses of participants (18–35 y.o.) divided into three conditions: a Immersive Virtual Reality experience, a slide-based lecture and a 2D desktop-based experience. Our results show that the virtual reality experience is considered more engaging and as effective as more traditional 2D and slide-based experiences in terms of learning

CCD-based imaging and 3D space--time mapping of terahertz fields via Kerr frequency conversion

We investigate the spatially and temporally resolved four-wave mixing of terahertz (THz) fields and optical pulses in large-bandgap dielectrics, such as diamond. We show that it is possible to perform beam profiling and space–time resolved mapping of THz fields by encoding the spatial information into an optical signal, which can then be recorded by a standard CCD camera

Terahertz Faraday rotation in a magnetic liquid: High magneto-optical figure of merit and broadband operation in a ferrofluid

We report on the demonstration of a high figure of merit (FOM) Faraday rotation in a liquid in the terahertz (THz) regime. Using a ferrofluid, a high broadband rotation (11 mrad/mm) is experimentally demonstrated in the frequency range of 0.2–0.9 THz at room temperature. Given the low absorption of the liquid, a high magneto-optical figure of merit (5-16 rad.cm/T) is obtained

Terahertz dipole nanoantenna arrays: resonance characteristics

Resonant dipole nanoantennas promise to considerably improve the capabilities of terahertz spectroscopy, offering the possibility of increasing its sensitivity through local field enhancement, while in principle allowing unprecedented spatial resolutions, well below the diffraction limit. Here, we investigate the resonance properties of ordered arrays of terahertz dipole nanoantennas, both experimentally and through numerical simulations. We demonstrate the tunability of this type of structures, in a range (∼1–2 THz) that is particularly interesting and accessible by means of standard zinc telluride sources. We additionally study the near-field resonance properties of the arrays, finding that the resonance shift observed between near-field and far-field spectra is predominantly ascribable to ohmic damping

Extraction of antibacterial active compounds from dry leaves of African plants of the Combretaceae family

The dry leaves of two African plants of the Combretaceae family, furnished by the botanist of the St. Jean de Dieu hospital of Tangueita (Benin, central Africa),were extracted with a sequence of 5 solvents with increasing polarity (from cyclohexane to water).The raw materials, obtained from these extractions following solvent evaporations, were tested for antibiotic activity against gram negative and gram positive bacterial strains. According to the results of a modified Kirby-Bauer test, no promising effect was obtained against Gram negative bacteria while interesting dose-effect activities were observed against Gram positive strains. In particular, from G. senegalensis active compounds were found in the low polarity extract (dichloromethane) which, at a concentration of 800 μg/disk (13 mm diameter disk), resulted in a grow inhibition crown of 4.7 mm and 2.6 mm on Enterococcus faecalis and Staphylococcus aureus MSSA, respectively. An higher amount of the aqueous extract (4760 μg/disk) also produced a good result as 5.7 mm and 5.0 mm crowns were observed. The extracts from C. micranthum showed an inhibiting effect in the more polar extracts (i.e. from ethanol and water) which gave 1 mm of grow inhibition crown on both strains at a concentration of 1000 μg/disk. The most promising extract from each plant was partially purified and then tested on some clinical relevant bacterial strains: S. aureus MRSA, Clostridium difficile, Streptococcus pyogenes, Streptococcus pneumoniae, Corynebacterium striatum, Neisseria gonorrhoeae, Haemophylus influenzae, Escherichia coli, obtaining a good killing effects on the Gram positive bacteria of the panel

Extremely large extinction efficiency and field enhancement in terahertz resonant dipole nanoantennas

The distinctive ability of nanometallic structures to manipulate light at the nanoscale has recently promoted their use for a spectacular set of applications in a wide range of areas of research including artificial optical materials, nano-imaging, biosensing, and nonlinear optics. Here we transfer this concept to the terahertz spectral region, demonstrating a metal nanostructure in shape of a dipole nanoantenna, which can efficiently resonate at terahertz frequencies, showing an effective cross section >100 times larger than its geometrical area, and a field enhancement factor of ~280, confined on a lateral section of ~λ/1,000. These results lead to immediate applications in terahertz artificial materials exhibiting giant dichroism, suggest the use of dipole nanoantennas in nanostructure-based terahertz metamaterials, and pave the way for nanoantenna-enhanced terahertz few-molecule spectroscopy and localized terahertz nonlinear optics