98 research outputs found
Andreev levels spectroscopy of topological three-terminal junctions
We calculate the differential conductance at a probe inserted in the weak
link of a topological Josephson junction, consisting of a semiconducting
nanowire deposited on top of two separated superconductors. Our aim is to
understand how the peculiar features in the spectrum of Andreev bound states,
arising due to the presence of Majorana bound states at the ends of the two
topological superconducting wires defining the junction, can be determined
through a measurement of the differential conductance. We find that when the
probe allows a single propagating mode, the differential conductance presents a
dip at zero voltage of zero conductance close to the position where the
spectrum exhibits the topologically protected crossing. This can be viewed as a
signature of the presence of Majorana states, which does not require fermion
parity conservation and is robust against parameters' changes, as well as
disorder. On the contrary, when the probe allows two or more propagating modes
the differential conductance resembles the spectrum of Andreev bound states.
This has been established making use of both numerical and analytical methods.Comment: 10 pages, 10 figures, published versio
Finite-frequency noise in a topological superconducting wire
In this paper we study the finite-frequency current cross-correlations for a
topological superconducting nanowire attached to two terminals at one of its
ends. Using an analytic 1D model we show that the presence of a Majorana bound
state yields vanishing cross-correlations for frequencies larger than twice the
applied transport voltage, in contrast to what is found for a zero-energy
ordinary Andreev bound state. Zero cross-correlations at high frequency have
been confirmed using a more realistic tight-binding model for finite-width
topological superconducting nanowires. Finite-temperature effects have also
been investigated.Comment: Contribution for the special issue of Physica E in memory of Markus
B\"uttiker. 9 pages, 7 figure
Thermopower of three-terminal topological superconducting systems
We study the thermopower of a three-terminal setup composed of a quantum dot
attached to three electrodes, one of which is a topological superconductor. In
the model, superconductivity is explicitly taken into account. We compare the
results for s-wave (trivial) and p-wave (topological) superconductors and
observe that for small temperatures the thermopower has different sign in the
two cases. This behavior is strongly dependent on temperature and we estimate
an energy scale that controls the sign in the p-wave case, which results
proportional to the square root of the gap and the coupling to superconductor.
The analytical results obtained with a simple 1D model are confirmed by a more
realistic tight-binding model.Comment: 10 pages, 15 figures, published versio
Separation of heat and charge currents for boosted thermoelectric conversion
In a multi-terminal device the (electronic) heat and charge currents can
follow different paths. In this paper we introduce and analyse a class of
multi-terminal devices where this property is pushed to its extreme limits,
with charge heat currents flowing in different reservoirs. After
introducing the main characteristics of such
regime we show how to realise it in a multi-terminal device with
normal and superconducting leads. We demonstrate that this regime allows to
control independently heat and charge flows and to greatly enhance
thermoelectric performances at low temperatures. We analyse in details a
three-terminal setup involving a superconducting lead, a normal lead and a
voltage probe. For a generic scattering region we show that in the regime of
heat-charge current separation both the power factor and the figure of merit
are highly increased with respect to a standard two-terminal system. These
results are confirmed for the specific case of a system consisting of three
coupled quantum dots.Comment: 12 pages, 8 figure
Tecniche integrate per la documentazione tridimensionale del sito di Valle Giumentina (Abruzzo, Italia) = Integrated 3D survey methods to document the Middle Pleistocene Site of Valle Giumentina (Abruzzo, Italy)
The paper deals with the research carried out by an interdisciplinary team in the Valle Giumentina, a Middle Pleistocene open-air site located in Central Italy (Abruzzo). bIn 2016 a three-dimensional survey of the site of Valle Giumentina has been planned and carried out by means of a laser scanner and close-range photogrammetry. They document the present state of the art of the stratigraphy and at the same time, they represent a 3D structure useful to position data collected in the previous investigations, in particular, the photos acquired during the first fieldworks by Radmilli in 50’s.bThe paper deals with this innovative approach addressed not only to visualize the site in 3D but also to analyse the state of preservation andbthe level of degradation in the course of time due to the natural changes. The communication will show the comparison between the old and the newbdocumentation positioned in a virtual 3D environment
The use of enabling tests to provide a qualitative measurement of the sport skill level of small soccer players
Evaluation tests represent a fundamental step in the educational path of working with small football players. The method used is of an experimental type whose aim is to analyse the capacity of children in the execution of three fundamental technical aspects of football: Short and Long Passage, Header shot and Shot on Target from a stationary position and in movement. We want to emphasize the importance of training the technical gesture starting from the little ones. In fact, too much tacticism combined with a continuous search for physicality in every area of the field has produced in the last decade an innumerable series of technically poorly trained players. The tests were performed on a sample of 12 children of 10 years old that play championship under-10. The data shows the score from each child during the execution of the various tests from which the total result was obtained by adding the points awarded for each attempt. The average of the high scores for the various tests was 13 for short pass; 27.3 for long pass; 3.6 for the header shot t; 9.6, and 7.75 respectively for stationary and moving shot on goal. The results can be used at the beginning of the activity and when a new group is available to identify the gaps to work on and then they can be repeated in other and different periods of the season to verify how effective the work done up to that point was
Preliminary work about the basis data for monitoring youth soccer team planning training
The youth soccer is always important especially for the assessment and the data of development of skills. The monitoring of them it could be important for the trainer to reorganize the planning of training and for the adaptation to individual athlete Aim of the study is to recruit the quantitative data about the anthropometric and performance aspects for reutilize to rearrangement of training planning. Method is experimental and has to carry out the usual parameters for monitoring the trainings. Anthropometric data are weight, height, BMI and performance data are Vo2max (Cooper) speed triangle test (three corner run) and speed test with (dribbling) on a sample are 13 athletes of 13 years old that play championship under 14 . BMI Data shows 6 weight, 4 in overweight risk and 3 in overweight. Cooper test data shows 2 above- average, 5 average, 5 below average and 1 poor. Mean speed triangle test 32.38 seconds, mean dibbling test 25.39 seconds. The results have to be useful for tool method of training
Nuove ricerche nel settore termale e del cd. vigneto della villa imperiale del Pausilypon di Napoli.
Progressive skin fibrosis is associated with a decline in lung function and worse survival in patients with diffuse cutaneous systemic sclerosis in the European Scleroderma Trials and Research (EUSTAR) cohort.
Objectives To determine whether progressive skin fibrosis is associated with visceral organ progression and mortality during follow-up in patients with diffuse cutaneous systemic sclerosis (dcSSc). Methods We evaluated patients from the European Scleroderma Trials and Research database with dcSSc, baseline modified Rodnan skin score (mRSS) ≥7, valid mRSS at 12±3 months after baseline and ≥1 annual follow-up visit. Progressive skin fibrosis was defined as an increase in mRSS >5 and ≥25% from baseline to 12±3 months. Outcomes were pulmonary, cardiovascular and renal progression, and all-cause death. Associations between skin progression and outcomes were evaluated by Kaplan-Meier survival analysis and multivariable Cox regression. Results Of 1021 included patients, 78 (7.6%) had progressive skin fibrosis (skin progressors). Median follow-up was 3.4 years. Survival analyses indicated that skin progressors had a significantly higher probability of FVC decline ≥10% (53.6% vs 34.4%; p<0.001) and all-cause death (15.4% vs 7.3%; p=0.003) than non-progressors. These significant associations were also found in subgroup analyses of patients with either low baseline mRSS (≤22/51) or short disease duration (≤15 months). In multivariable analyses, skin progression within 1 year was independently associated with FVC decline ≥10% (HR 1.79, 95% CI 1.20 to 2.65) and all-cause death (HR 2.58, 95% CI 1.31 to 5.09). Conclusions Progressive skin fibrosis within 1 year is associated with decline in lung function and worse survival in dcSSc during follow-up. These results confirm mRSS as a surrogate marker in dcSSc, which will be helpful for cohort enrichment in future trials and risk stratification in clinical practice
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