Optical supercavitation in soft-matter

We investigate theoretically, numerically and experimentally nonlinear optical waves in an absorbing out-of-equilibrium colloidal material at the gelification transition. At sufficiently high optical intensity, absorption is frustrated and light propagates into the medium. The process is mediated by the formation of a matter-shock wave due to optically induced thermodiffusion, and largely resembles the mechanism of hydrodynamical supercavitation, as it is accompanied by a dynamic phase-transition region between the beam and the absorbing material.Comment: 4 pages, 5 figures, revised version: corrected typos and reference

Acoustic charge transport in n-i-n three terminal device

We present an unconventional approach to realize acoustic charge transport devices that takes advantage from an original input region geometry in place of standard Ohmic input contacts. Our scheme is based on a n-i-n lateral junction as electron injector, an etched intrinsic channel, a standard Ohmic output contact and a pair of in-plane gates. We show that surface acoustic waves are able to pick up electrons from a current flowing through the n-i-n junction and steer them toward the output contact. Acoustic charge transport was studied as a function of the injector current and bias, the SAW power and at various temperatures. The possibility to modulate the acoustoelectric current by means of lateral in-plane gates is also discussed. The main advantage of our approach relies on the possibility to drive the n-i-n injector by means of both voltage or current sources, thus allowing to sample and process voltage and current signals as well.Comment: 9 pages, 3 figures. Submitted to Applied Physics Letter

The safety assessment of Campotosto Lake dams following 2016-2017 seismic sequence in Central Italy. Focus on Poggio Cancelli embankment dam

The Campotosto Lake is one of the biggest reservoirs of Europe, with a storage capacity exceeding 200 million of m3. The natural original lake was confined with three large dams owned by Enel. In the recent past, the lake and the dams have been subjected to a series of seismic events known as the seismic sequence of L'Aquila in 2009 and the seismic sequence of Central Italy in 2016-17. Following the last one, Enel promptly decided to temporarily lower the water level to carry out surveys, measurements and automatic monitoring activities. Based on available data, in order to verify, ensure and asseverate the safety conditions of the dams and the lake’s slopes, a series of multi-disciplinary studies and in-depth analysis were specifically conducted. Detailed studies were developed for the Poggio Cancelli embankment dam: geotechnical surveys, geophysical in situ tests and “advanced” laboratory tests in order to define at best the foundation soil characteristics, thus reasonably excluding the liquefaction risk applying sophisticated methods of analysis. Moreover, InSAR analysis allowed to retrieve the displacement history of the sites and confirmed the topographic measurements taken before and after the earthquakes. Displacement data, together with the real accelerograms recorded at the dam toe were used for a back analysis of the settlements by means of a FEM model of the dam. With this validated model, it was possible to simulate the seismic response of the embankment in the catastrophic scenario represented by the worst expected earthquake at the site. However, recent and important research contributed to establish the position and associated potential magnitude of the Campotosto fault. They indicate that the seismic scenario adopted by our analysis is precautionary, therefore our results are conservative. Seismic assessments on the other dams and InSAR analysis of the slopes surrounding the reservoir were also carried out. All these studies were concluded in 2020 showing good results and satisfactory safety factors, allowing Enel to set up again Campotosto reservoir to normal water levels

Auroras on Mars: from Discovery to New Developments

Auroras are emissions in a planetary atmosphere caused by its interactions with the surrounding plasma environment. They have been observed in most planets and some moons of the solar system. Since their first discovery in 2005, Mars auroras have been studied extensively and is now a rapidly growing area of research. Since Mars lacks an intrinsic global magnetic field, its crustal field is distributed throughout the planet and its interactions with the surrounding plasma environment lead to a number of complex processes resulting in several types of auroras uncommon on Earth. Martian auroras have been classified as diffuse, discrete and proton aurora. With new capability of synoptic observations made possible with the Hope probe, two new types of auroras have been observed. One of them, which occurs on a much larger spatial scale, covering much of the disk, is known as discrete sinuous aurora. The other subcategory is one of proton auroras observed in patches. Further study of these phenomena will provide insights into the interactions between the atmosphere, magnetosphere and the surrounding plasma environment of Mars. We provide a brief review of the work done on the subject in the past 17 years since their discovery, and report new developments based on observations with Hope probe.Comment: 14 pages, 7 figure

Determination of the optimal priming interval of rumen fluids used as inocula for the in vitro digestibility trials through radial enzyme diffusion method

Context: Determination of the neutral detergent fibre digestibility is one of the important parameters to consider when formulating diets. However, the in vitro determination shows low repeatability because of the source of rumen-fluid inoculum. Priming of the rumen fluid inocula, obtained through an oesophageal probe, has been proposed to overcome this issue. Aim: The objective of the study was to investigate the evolution of the microbial enzymatic activities of different rumen fluids during a priming procedure, to establish the fermentation interval that minimises the differences among rumen-fluid degradative potentials. Methods: Three farms for each type of diet were involved in the study. Rumen fluids were obtained from dry and lactating cows fed the following four diet types: 100% hay or a diet with 80: 20 forage: Concentrate ratio (F: C) as dry-cow diets, and ad libitum hay and concentrate, or a total mixed ration (both at 60: 40 F: C) as lactating-cow diets. On each farm, rumen fluid was collected from three Holstein cows by using an oesophageal probe, and mixed. Two aliquots of each rumen fluid mix were added to the medium containing the same priming substrate in an in vitro batch-fermentation system. During the incubation, the fermentation fluids were sampled in duplicate at 0-, 1-, 2-, 4-, 8-, 24- A nd 48-h intervals. Enzymatic activities of amylase, cellulase and xylanase were determined by radial enzyme diffusion method. Key results: Initial enzymatic activities were quite variable and increased with an increasing incubation time. By 24 h, amylase showed similar values among high-concentrate diet fermentation fluids, and a lower data dispersion in comparison to the other intervals cellulase was characterised by similar values in all the fermentation fluids derived from diets including concentrates, and xylanase showed similar activity in the fermentation fluids derived from high-concentrate diets. Development of the enzymatic activity of the fermentation fluids derived from the 100% hay diet differed from the others. Conclusions: A 24-h priming procedure was needed to stabilise and equalise the enzymatic activity of the rumen fluid from cows fed high-concentrate diets. This was not observed in rumen fluid from cows fed hay-based diets. Implications: The 24-h-primed rumen fluid can be used to increase the repeatability of neutral detergent fibre digestibility determination

Precise determination of 6^6Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules

We employ radio-frequency spectroscopy on weakly bound $^6$Li$_2$ molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold $^6$Li atoms based on a multi-channel quantum scattering model. We determine the singlet and triplet scattering lengths to be $a_s=45.167(8)a_0$ and $a_t=-2140(18)a_0$ (1 $a_0$ = 0.0529177 nm), and the positions of the broad Feshbach resonances in the energetically lowest three $s-$wave scattering channels to be 83.41(15) mT, 69.04(5) mT, and 81.12(10) mT

What do adolescents with asthma really think about adherence to inhalers? Insights from a qualitative analysis of a UK online forum

ADS is funded by an NIHR Academic Clinical Lectureship. AB is an NIHR Senior Investigator and additionally was supported by the NIHR Respiratory Disease. RH was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research (CLAHRC) North Thames at Barts NHS Trust. The views expressed are those of the author(s) and not necessarily those of the NHS, NIHR or Department of Health