Transient growth in the flow past a three-dimensional smooth roughness element

This work provides a global optimization analysis, looking for perturbations inducing the largest energy growth at a finite time in a boundary-layer flow in the presence of smooth three-dimensional roughness elements. Amplification mechanisms are described which can bypass the asymptotical growth of Tollmien–Schlichting waves. Smooth axisymmetric roughness elements of different height have been studied, at different Reynolds numbers. The results show that even very small roughness elements, inducing only a weak deformation of the base flow, can localize the optimal disturbance characterizing the Blasius boundary-layer flow. Moreover, for large enough bump heights and Reynolds numbers, a strong amplification mechanism has been recovered, inducing an increase of several orders of magnitude of the energy gain with respect to the Blasius case. In particular, the highest value of the energy gain is obtained for an initial varicose perturbation, differently to what found for a streaky parallel flow. Optimal varicose perturbations grow very rapidly by transporting the strong wall-normal shear of the base flow, which is localized in the wake of the bump. Such optimal disturbances are found to lead to transition for initial energies and amplitudes considerably smaller than sinuous optimal ones, inducing hairpin vortices downstream of the roughness element

Indirect Sensitivity to Heavy Z' Bosons at a Multi-TeV e+e- Collider

We compare the phenomenology of two models, the so-called minimal Z' and an effective model for a SM-like Higgs realised as a composite state of a new strong interaction, at a multi-TeV linear collider in the hypothesis that the new physics is at a scale beyond the direct reach of the machine.Comment: 6 pages, 5 figures, to appear in the Proceedings of the International Workshop on Future Linear Colliders LCWS201

Future Electron-Positron Colliders and the 4-Dimensional Composite Higgs Model

In this note we analyse the prospects of a future electron-positron collider in testing a particular realisation of a composite Higgs model encompassing partial compositeness, namely, the 4-Dimensional Composite Higgs Model. We study the main Higgs production channels for three possible energy stages and different luminosity options of such a machine and confront our results to the expected experimental accuracies in the various Higgs decay channels accessible herein and, for comparison, also at the Large Hadron Collider.Comment: 24 pages, 10 figures, minor corrections for publication in JHE

Top pair production at a future e+e−e^+e^- machine in a composite Higgs scenario

The top quark plays a central role in many New Physics scenarios and in understanding the details of Electro-Weak Symmetry Breaking. In the short- and mid-term future, top-quark studies will mainly be driven by the experiments at the Large Hadron Collider. Exploration of top quarks will, however, be an integral part of particle physics studies at any future facility and an $e^+ e^-$ collider will have a very comprehensive top-quark physics program. We discuss the possibilities of testing NP in the top-quark sector within a composite Higgs scenario through deviations from the Standard Model in top pair production for different Centre-of-Mass energy options of a future $e^+e^-$ machine. In particular, we focus on precision studies of the top-quark sector at a CM energy ranging from 370 GeV up to 3 TeV.Comment: 23 pages, 10 figures; v2: minor corrections, published on JHE

Probing New Scales at a e+e- Linear Collider

Extending the sensitivity to New Physics beyond the anticipated reach of the LHC is a prime aim of future colliders. This paper summarises the potential of an e+e- linear collider, at and beyond 1 TeV, using a realistic simulation of the detector response and the accelerator induced background. The possible LC energy-luminosity trade-offs offered in probing multi-TeV scales for new phenomena with electro-weak observables are also discussed

Intestinal Microbiota, Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma: The Potential Role of Dysbiosis in the Hepatocarcinogenesis

Introduction: Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. Approximately 5–30% of HCC patients lack a readily identifiable risk factor for their cancer, and most of these cases are attributed to nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH)

Environment-Induced Reversible Modulation of Optical and Electronic Properties of Lead Halide Perovskites and Possible Applications to Sensor Development: A Review

none4siLead halide perovskites are currently widely investigated as active materials in photonic and optoelectronic devices. While the lack of long term stability actually limits their application to commercial devices, several experiments demonstrated that beyond the irreversible variation of the material properties due to degradation, several possibilities exist to reversibly modulate the perovskite characteristics by acting on the environmental conditions. These results clear the way to possible applications of lead halide perovskites to resistive and optical sensors. In this review we will describe the current state of the art of the comprehension of the environmental effects on the optical and electronic properties of lead halide perovskites, and of the exploitation of these results for the development of perovskite-based sensors.openDe Giorgi, ML; Milanese, S; Klini, A; Anni, MDe Giorgi, Ml; Milanese, S; Klini, A; Anni,

Lithium limits trimethyltin-induced cytotoxicity and proinflammatory response in microglia without affecting the concurrent autophagy impairment

Trimethyltin (TMT) is a highly toxic molecule present as an environmental contaminant causing neurodegeneration particularly of the limbic system both in humans and in rodents. We recently described the occurrence of impairment in the late stages of autophagy in TMT-intoxicated astrocytes. Here we show that similarly to astrocytes also in microglia, TMT induces the precocious block of autophagy indicated by the accumulation of the autophagosome marker, microtubule associated protein light chain 3. Consistent with autophagy impairment we observe in TMT-treated microglia the accumulation of p62/SQSTM1, a protein specifically degraded through this pathway. Lithium has been proved effective in limiting neurodegenerations and, in particular, in ameliorating symptoms of TMT intoxication in rodents. In our in vitro model, lithium displays a pro-survival and anti-inflammatory action reducing both cell death and the proinflammatory response of TMT-treated microglia. In particular, lithium exerts these activities without reducing TMT-induced accumulation of light chain 3 protein. In fact, the autophagic block imposed by TMT is unaffected by lithium administration. These results are of interest as defects in the execution of autophagy are frequently observed in neurodegenerative diseases and lithium is considered a promising therapeutic agent for these pathologies. Thus, it is relevant that this cation can still maintain its pro-survival and anti-inflammatory role in conditions of autophagy bloc

Reliability and use of Copenhagen Burnout Inventory in italian sample of university professors

Academics often have to face with burnout syndrome at work. This cross-sectional study evaluates the reliability of the Italian version of the Copenhagen Burnout Inventory (CBI) in a sample of Academics of Sapienza University of Faculty of Medicine and Pharmacy, through an online questionnaire composed of the CBI, SF12 Health Survey, and Positivity Scale. Univariate, bivariate, multivariate analyses, and Cronbach α coefficients of CBI were performed. Ninety-five participants completed the questionnaire (response rate 85%). Cronbach’s α of the three domains were high (0.892, 0.868, and 0.836). Women, younger and part time professors reported higher score in personal (p = 0.025; 0.060) and work burnout. In multivariate analysis decreasing age (β = −0.263; p = 0.001); being a professor in environmental technicians (β = −0.120; p = 0.098); and low mental (β = −0.263; p = 0.020), physical (β = −0.319; p ≤ 0.001) and positivity scores (β = −0.237; p = 0.031) predict significantly higher personal burnout. Low physical (β = −0.346; p < 0.001) and mental (β = − 0.249; p = 0.013) positivity (β = −0.345; p = 0.001) scores; fewer years of work (β = −0.269; p ≤ 0.001); and being a medical or nursing professor (β = 0.169; p = 0.016) predicts high work burnout. Low MCS predicts a high level of student burnout. Results suggest that the Italian version of the CBI is a reliable instrument. Further research should focus on the prevalence of burnout in academics