196,129 research outputs found
Microscopic Study of Static and Dynamical Properties of Dilute One-Dimensional Soft Bosons
No full textWe study static properties and the dynamical structure factor of zero-temperature dilute bosons interacting via a soft-shoulder potential in one dimension. Our approach is fully microscopic and employs state-of-the-art quantum Monte Carlo and analytic continuation techniques. By increasing the interaction strength, our model reproduces the Lieb–Liniger gas, the Tonks–Girardeau and the hard-rods models
Coronary artery disease associated with severe mitral and tricuspid valve regurgitation after left Pneumonectomy: report of a successful hybrid procedure
No full textThe literature concerning heart surgery after pneumonectomy is still poor. Moreover, there is still a lack of a standardized approach to such a patient in the decision-making process. Here, we report a case of a patient who had previously had left pneumonectomy for malignancy and who had coronary artery disease and mitral and tricuspid regurgitation treated with a hybrid procedure
A note on the ice crystallography and geochemistry of a debris cone, Northern Foothills, Antarctica
No full textDEDALO: Device for Enhanced Dust Analyses with Light Obscuration sensors
No full textInstruments based on light obscuration sensors are widely used for measuring the size distribution of insoluble sub-visible particles in liquid suspensions, being fast and suitable for in situ and real-time measurements. Such instruments are typically calibrated by means of reference polystyrene spherical particles with a specific refractive index, which unavoidably leads to systematic errors when determining the size of particles of different materials. In this paper, we propose a reliable and consistent method to overcome this limitation by setting the refractive index value according to the sample, thus achieving an improved particle size distribution (PSD) measurement. An ad hoc, ready-to-use, open source code with a graphical interface able to drive an in-line instrument and obtain a real-time correction to the PSD has been developed. The method has been extensively validated with several oil emulsions characterized by different refractive index values and the results have been compared with an independent optical method. As an example of application, we have adopted this approach for the analysis of dust suspended in meltwater of an ice core from a glacier in the Aosta Valley (Italy). We believe that our approach will strongly improve the accuracy in characterizing liquid suspensions and reduce discrepancies between data obtained with different methods. The code has been made publicly available at: https://instrumentaloptics.fisica.unimi.it/dedalo/ and on the GitHub page of the corresponding author (https://github.com/LucaTeruzzi/DEDALO)
Citrate anticoagulation during CVVH in high risk bleeding patients
No full textBackground: Regional citrate anticoagulation (RCA) is an effective form of anticoagulation for continuous renal replacement therapy (CRRT) in patients with contraindications to heparin. Its use has been very limited, possibly because of the need for special infusion solutions and difficult monitoring of the metabolic effects.
Objective: To investigate the safety and the feasibility of an RCA method for continuous veno-venous hemofiltration (CVVH) using commercially available replacement fluid.
Methods: We evaluated 11 patients at high risk of bleeding, requiring CVVH. RCA was performed using commercially available replacement fluid solutions to maintain adequate acid-base balance. We adjusted the rate of citrate infusion to achieve a post-filter ionized calcium concentration [iCa] 250 ml/min. When needed, we infused calcium gluconate to maintain systemic plasma [iCa] within the normal range.
Results: Twenty-nine filters ran for a total of 965.5 h. Average filter life was 33.6 +/- 20.5 h. Asymptomatic hypocalcemia was detected in 6.9% of all samples. No [iCa] values < 0.9 mmol/L were observed. Hypercalcemia (1.39 +/- 0.05 mmol/L) occurred in 2.5% of all samples. We observed hypematremia (threshold 153 mmol/L) and alkalosis (threshold 7.51) in only 9.3% and 9.4% respectively of all samples, mostly concomitantly. No patient showed any signs of citrate toxicity.
Conclusions: We developed a protocol for RCA during CVVH using commercially available replacement fluid that proved safe, flexible and applicable in an Intensive Care Unit (ICU) setting
An experience of innovative learning with multimodal teaching techniques in nuclear physics education in Italy
No full textDespite significant recent advances in applied nuclear physics (NP) research,
the teaching of these topics in high schools has remained largely unchanged
and often marginal. We have developed an educational pathway on NPs for
high school students that combines active innovative methodologies
including puzzles, questionnaires, inclusive teaching, and an inquiry-based
learning approach. The content is presented differently from traditional
textbooks and established practices. To evaluate the effectiveness of this
approach, we implemented the activity in a final-year high school class (13th
grade) composed of low-performing students. We present the outcomes of
oral examinations, written tests, and satisfaction surveys
Single-shot measurement of phase and topological properties of orbital angular momentum radiation through asymmetric lateral coherence
No full textWe show a single-shot technique to measure topological and phase properties of radiation carrying orbital angular momentum. The single-shot method is effectively described as the one-dimensional case of a more general two-dimensional approach based on scanning interferometry (asymmetric lateral coherence). The validity of the method has been experimentally verified and the applicability to ultrarelativistic sources of hard x-rays has been discussed. The method is suitable to characterize phase and topological properties of x-ray sources by using simple apertures
A Markov state modeling analysis of sliding dynamics of a 2D model
No full textNon-equilibrium Markov State Modeling (MSM) has recently been proposed by Pellegrini et al. [Phys. Rev. E 94, 053001 (2016)] as a possible route to construct a physical theory of sliding friction from a long steady state atomistic simulation: the approach builds a small set of collective variables, which obey a transition-matrix-based equation of motion, faithfully describing the slow motions of the system. A crucial question is whether this approach can be extended from the original 1D small size demo to larger and more realistic size systems, without an inordinate increase of the number and complexity of the collective variables. Here we present a direct application of the MSM scheme to the sliding of an island made of over 1000 harmonically bound particles over a 2D periodic potential. Based on a totally unprejudiced phase space metric and without requiring any special doctoring, we find that here too the scheme allows extracting a very small number of slow variables, necessary and sufficient to describe the dynamics of island sliding
An unusual mechanical aortic prosthetic valve dysfunction : role of a diagnostic multimodality imaging protocol
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