182 research outputs found
Electromagnetic response of strongly coupled plasmas
We present a thorough analysis of the electromagnetic response of strongly
coupled neutral plasmas described by the gauge/gravity correspondence. The
coupling of the external electromagnetic field with the tower of quasi-normal
modes of the plasmas supports the presence of various electromagnetic modes
with different properties. Among them we underline the existence of negative
refraction with low dissipation for a transverse non-hydrodynamical mode.
Previous hydrodynamical approaches have shown the ubiquitous character of
negative refraction in charged plasmas and the absence thereof in neutral
plasmas. Our results here extend the analysis for neutral plasmas beyond the
hydrodynamical regime. As an application of these new insights we briefly
discuss the case of the quark gluon plasma in the temperature dominated regime.Comment: 29 pages, 15 figure
Italian consensus on the therapeutic management of uncomplicated acute hematogenous osteomyelitis in children
A combination of infraclavicular and suprascapular nerve blocks for total shoulder arthroplasty: A case series
Background - Shoulder arthroplasty is associated with significant post-operative pain. Interscalene plexus block is the gold standard for pain management in patients undergoing this surgery, however, alternatives are currently being developed. We hypothesized that a combination of anterior suprascapular nerve block and lateral sagittal infraclavicular block would provide effective post-operative analgesia. Primary aims for this study were to document numeric rating scale (NRS) pain score and use of oral morphine equivalents (OMEq) during the first 24 hours after surgery. Secondary aim was to determine the incidence of hemidiaphragmatic paralysis.
Methods - Twenty patients (ASA physical status I-III) scheduled for shoulder arthroplasty were studied. Four mL ropivacaine 0.5% was administered for the suprascapular nerve block and 15 mL ropivacaine 0.75% for the infraclavicular block. Surgery was performed under general anaesthesia. Paracetamol and prolonged-release oxycodone were prescribed as post-operative analgesics. Morphine and oxycodone were prescribed as rescue pain medication. Diaphragm status was assessed by ultrasound.
Results - Median NRS (0-10) at 1, 3, 6, 8 and 24 hours post-operatively were 1, 0, 0, 0 and 3, respectively. NRS at rest during the first 24 post-operative hours was 4 (2.5-4.5 [0-5]), median (IQR [range]). Maximum NRS was 6.5 (5-8 [0-10]) median (IQR [range]). Total OMEq during the first 24 post-operative hours was 52.5 mg (30-60 [26.4-121.5]) median (IQR [range]). Hemidiaphragmatic paralysis was diagnosed in one patient (5%).
Conclusions - The combination of suprascapular and infraclavicular nerve block shows an encouraging post-operative analgesic profile and a low risk for hemidiaphragmatic paralysis after total shoulder arthroplasty
Manutenzione di opere a gradinata e riqualificazione dei corsi d’acqua montani. Approccio multiobiettivo per gli interventi sulle briglie a gradinata nel Rio Preit, Canosio (CN), Regione Piemonte.
Wine Traceability with Rare Earth Elements
The traceability of foodstuffs is now a relevant aspect of the food market. Scientific research has been devoted to addressing this issue by developing analytical protocols in order to find the link between soil and food items. In this view, chemical parameters that can act as soil markers are being sought. In this work, the role of rare earth elements (REEs) as geochemical markers in the traceability of red wine is discussed. The REE distribution in samples from each step of the wine making process of Primitivo wine (produced in Southern Italy) was determined using the highly sensitive inductively coupled plasma-mass spectrometry (ICP-MS) technique. Samples analyzed include grapes, must, and wine samples after every step in the vinification process. The resulting data were compared to the REE distribution in the soil, revealing that the soil fingerprint is maintained in the intermediate products up to and including grape must. Fractionation occurs thereafter as a consequence of further external interventions, which tends to modify the REE profile
Exports and Productivity: Comparable Evidence for 14 Countries
We use comparable micro level panel data for 14 countries and a set of identically specified empirical models to investigate the relationship between exports and productivity. Our overall results are in line with the big picture that is by now familiar from the literature: Exporters are more productive than non-exporters when observed and unobserved heterogeneity are controlled for, and these exporter productivity premia tend to increase with the share of exports in total sales; there is strong evidence in favour of self-selection of more productive firms into export markets, but nearly no evidence in favour of the learning-by-exporting hypothesis. We document that the exporter premia differ considerably across countries in identically specified empirical models. In a meta-analysis of our results we find that countries that are more open and have more effective government report higher productivity premia. However, the level of development per se does not appear to be an explanation for the observed cross-country differences.exports; productivity; micro data; international comparison
Rainbow labyrinthine metamaterials for sound absorption applications
This work presents a proof-of-concept experiment demonstrating the efficient noise absorption of a 3-D printed panel, designed with arranged space-coiling labyrinthine elementary cells of various sizes to induce a rainbow effect. Numerical simulations are used to simulate absorption characteristics of the single labyrinthine units, and optimization methods are employed to further investigate the performance dependence on the geometry and thermoviscous phenomena. The dependence of absorption characteristics on cell thickness and lateral size is then experimentally verified. The resonance frequency is found to scale close to linearly with respect to both thickness and lateral size, allowing for tunability of the working frequency. Using these data, a panel is designed by arranging cells of different sizes in quasi-periodic lattice to exploit the acoustic ”rainbow” effect, resulting in a wider absorption spectrum covering the frequency range between 800 and 1200 Hz, which can be of particular interest in aeronautic applications. The performance of the panel is experimentally validated in a small-scale reverberation room, showing close to ideal values of absorption at the desired frequency of operation. This work suggests a design procedure for noise-mitigation panel solutions and provides experimental evidence of the versatility and effectiveness of labyrinthine metamaterials for tunable frequency sound attenuation
Pulmonary Lobectomy for Early-Stage Lung Cancer with Uniportal versus Three-Portal Video-Assisted Thoracic Surgery: Results from a Single-Centre Randomized Clinical Trial
Video-assisted thoracic surgery (VATS) is a consolidated approach; however, there is no consensus on the number of ports leading to less postoperative pain. We compared early postoperative pain after uniportal and three-portal VATS lobectomy for early-stage NSCLC. In this randomized clinical trial, patients undergoing VATS lobectomy were randomly assigned to receive uniportal (U-VATS Group) or three-portal (T-VATS Group) VATS. The inclusion criteria were age ≤ 80 years and ASA < 4. The exclusion criteria were clinical T3, previous thoracic surgery, induction therapy, chest radiotherapy, connective tissue or vascular diseases, major organ failure, and analgesics or corticosteroids use. The postoperative analgesia protocol was based on NRS. Pain was measured as analgesic consumption; the secondary endpoints were intra- and postoperative complications, conversion rate, surgical time, dissected lymph nodes, hospital stay, and respiratory function. Out of 302 eligible patients, 120 were included; demographics were distributed homogeneously. The mean cumulative morphine consumption (CMC) in the U-VATS Group after 7 days was lower than in the T-VATS Group (77.4 mg vs. 90.1 mg, p = 0.003). Intraoperative variables and postoperative complications were comparable. The 30-day intercostal neuralgia rate was lower in the U-VATS Group, without reaching statistical significance. Patients undergoing U-VATS showed a lower analgesic consumption compared with the T-VATS Group; analgesic consumption was moderate in both groups
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Citrate anion improves chronic dialysis efficacy, reduces systemic inflammation and prevents Chemerin-mediated microvascular injury
Systemic inflammation and uremic toxins (UT) determine the increased cardiovascular mortality observed in chronic hemodialysis (HD) patients. Among UT, the adipokine Chemerin induces vascular dysfunction by targeting both endothelial and vascular smooth muscular cells (EC and VSMC). As Citrate anion modulates oxidative metabolism, systemic inflammation and vascular function, we evaluated whether citrate-buffered dialysis improves HD efficiency, inflammatory parameters and chemerin-mediated microvascular injury. 45 patients were treated in sequence with acetate, citrate and, again, acetate-buffered dialysis solution (3 months per interval). At study admission and after each treatment switch, we evaluated dialysis efficacy and circulating levels of chemerin and different inflammatory biomarkers. In vitro, we stimulated EC and VSMC with patients' plasma and we investigated the role of chemerin as UT. Citrate dialysis increased HD efficacy and reduced plasma levels of CRP, fibrinogen, IL6 and chemerin. In vitro, patients' plasma induced EC and VSMC dysfunction. These effects were reduced by citrate-buffered solutions and paralleled by the decrease of chemerin levels. Consistently, chemerin receptor knockdown reduced EC and VSMC dysfunction. In conclusion, Switching from acetate to citrate improved dialysis efficacy and inflammatory parameters; in vitro, chemerin-induced EC and VSMC injury were decreased by using citrate as dialysis buffer
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