Validazione di Piani di Disaster Recovery mediante Simulatore

Contribution published online at: http://www.mimos.it/nuovo/contenuto_view.asp?check=10

Perturbing exactly tri-bimaximal neutrino mixings with charged lepton mass matrices

We study perturbations of exactly tri-bimaximal neutrino mixings under the assumption that they are coming solely from the charged lepton mass matrix. This may be plausible in scenarios where the mass generation mechanisms of neutrinos and charged leptons/quarks have a different origin. As a working hypothesis, we assume mass textures which may be generated by the Froggatt-Nielsen mechanism for the charged lepton and quark sectors, which generically leads to strong hierarchies, whereas the neutrino sector is exactly tri-bimaximal with a mild (normal) hierarchy. We find that in this approach, deviations from maximal atmospheric mixing can be introduced without affecting theta_13 and theta_12, whereas a deviation of theta_13 or theta_12 from its tri-bimaximal value will inevitably lead to a similar-sized deviation of the other parameter. Therefore, the already very precise knowledge of theta_12 points towards small sin^2(2 theta_13) <= 0.01. The magnitude of this deviation can be controlled by the specific form of the charged lepton texture.Comment: 13 pages, 9 figures; matches published version, changes in notatio

The Reproducibility of a Kinematically-Derived Axis of the Knee versus Digitized Anatomical Landmarks using a Knee Navigation System

Component position is critical to longevity of knee arthroplasties. Femoral component rotation is typically referenced from the transepicondylar axis (TEA), the anterior-posterior (AP) axis or the posterior condylar axis. Other studies have shown high variability in locating the TEA while proposing digitization of other landmarks such as the AP axis as a less-variable reference. This study uses a navigation system to compare the reproducibility of computing a kinematically-derived, navigated knee axis (NKA) to digitizing the TEA and AP axis. Twelve knees from unembalmed cadavers were tested. Four arthroplasty surgeons digitized the femoral epicondyles and the AP axis direction as well as flexed and extended the knee repeatedly to allow for NKA determination. The variance of the NKA axis determined under neutral loading conditions was smaller than the variance of the TEA axis when the kinematics were measured in the closed surgical condition (P<0.001). However, varus, valgus, and internal loading of the leg increased the variability of the NKA. Distraction of the leg during knee flexion and extension preserved the low variability of the NKA. In conclusion, a kinematically-derived NKA under neutral or distraction loading is more reproducible than the TEA and AP axis determined by digitization

Understanding and Overcoming the Challenges Related to Cardiovascular Trials Involving Patients with Kidney Disease.

Cardiovascular disease is a prevalent and prognostically important comorbidity among patients with kidney disease, and individuals with kidney disease make up a sizeable proportion (30%-60%) of patients with cardiovascular disease. However, several systematic reviews of cardiovascular trials have observed that patients with kidney disease, particularly those with advanced kidney disease, are often excluded from trial participation. Thus, currently available trial data for cardiovascular interventions in patients with kidney disease may be insufficient to make recommendations on the optimal approach for many therapies. The Kidney Health Initiative, a public-private partnership between the American Society of Nephrology and the US Food and Drug Administration, convened a multidisciplinary, international work group and hosted a stakeholder workshop intended to understand and develop strategies for overcoming the challenges with involving patients with kidney disease in cardiovascular clinical trials, with a particular focus on those with advanced disease. These efforts considered perspectives from stakeholders, including academia, industry, contract research organizations, regulatory agencies, patients, and care partners. This article outlines the key challenges and potential solutions discussed during the workshop centered on the following areas for improvement: building the business case, re-examining study design and implementation, and changing the clinical trial culture in nephrology. Regulatory and financial incentives could serve to mitigate financial concerns with involving patients with kidney disease in cardiovascular trials. Concerns that their inclusion could affect efficacy or safety results could be addressed through thoughtful approaches to study design and risk mitigation strategies. Finally, there is a need for closer collaboration between nephrologists and cardiologists and systemic change within the nephrology community such that participation of patients with kidney disease in clinical trials is prioritized. Ultimately, greater participation of patients with kidney disease in cardiovascular trials will help build the evidence base to guide optimal management of cardiovascular disease for this population

Tri-Bimaximal Neutrino Mixing and Discrete Flavour Symmetries

We review the application of non-Abelian discrete groups to Tri-Bimaximal (TB) neutrino mixing, which is supported by experiment as a possible good first approximation to the data. After summarizing the motivation and the formalism, we discuss specific models, mainly those based on A4 but also on other finite groups, and their phenomenological implications, including the extension to quarks. The recent measurements of \theta_13 favour versions of these models where a suitable mechanism leads to corrections to \theta_13 that can naturally be larger than those to \theta_12 and \theta_23. The virtues and the problems of TB mixing models are discussed, also in connection with lepton flavour violating processes, and the different approaches are compared.Comment: 26 pages, 5 figures, 4 tables. V3 submitted to add an acknowledgment to a network. Review written for the special issue on "Flavor Symmetries and Neutrino Oscillations", published in Fortschritte der Physik - Progress of Physic

The Interplay Between GUT and Flavour Symmetries in a Pati-Salam x S4 Model

Both Grand Unified symmetries and discrete flavour symmetries are appealing ways to describe apparent structures in the gauge and flavour sectors of the Standard Model. Both symmetries put constraints on the high energy behaviour of the theory. This can give rise to unexpected interplay when building models that possess both symmetries. We investigate on the possibility to combine a Pati-Salam model with the discrete flavour symmetry $S_4$ that gives rise to quark-lepton complementarity. Under appropriate assumptions at the GUT scale, the model reproduces fermion masses and mixings both in the quark and in the lepton sectors. We show that in particular the Higgs sector and the running Yukawa couplings are strongly affected by the combined constraints of the Grand Unified and family symmetries. This in turn reduces the phenomenologically viable parameter space, with high energy mass scales confined to a small region and some parameters in the neutrino sector slightly unnatural. In the allowed regions, we can reproduce the quark masses and the CKM matrix. In the lepton sector, we reproduce the charged lepton masses, including bottom-tau unification and the Georgi-Jarlskog relation as well as the two known angles of the PMNS matrix. The neutrino mass spectrum can present a normal or an inverse hierarchy, and only allowing the neutrino parameters to spread into a range of values between $\lambda^{-2}$ and $\lambda^2$, with $\lambda\simeq0.2$. Finally, our model suggests that the reactor mixing angle is close to its current experimental bound.Comment: 62 pages, 4 figures; references added, version accepted for publication in JHE

Outcome of Contemporary Percutaneous Coronary Intervention in the Elderly and the Very Elderly: Insights From the Blue Cross Blue Shield of Michigan Cardiovascular Consortium

Background: There is a paucity of data on the outcome of contemporary percutaneous coronary intervention (PCI) in the elderly. Accordingly, we assessed the impact of age on outcome of a large cohort of patients undergoing PCI in a regional collaborative registry. Hypothesis: Increasing age is associated with a higher incidence of procedural‐related complications. Methods: We evaluated the outcome of 152373 patients who underwent PCI from 2003 to 2008 in the 31 hospitals participating in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium. The procedural outcomes of the cohort were compared by dividing patients into <70 years of age, 70 to 79 years, 80 to 84 years, 85 to 89 years, and ≥90 years. Results: Of the cohort, 64.64% were <70 years of age, 23.83% were 70 to 79 years, 7.85% were 80 to 84 years, 3.09% were 85 to 89 years, and 0.58% were 90 years or older. Increasing age was associated with an increase in all‐cause in‐hospital mortality, contrast‐induced nephropathy, transfusion, stroke/transient ischemic attack, and vascular complications. The overall in‐hospital mortality rate was 1.09% and increased from 0.67% in those younger than 70 years up to 5.44% in those 90 years old or greater. The mortality rate in patients over 80 years approached 12% to 15% for those with ST‐segment myocardial infarction and 39% in cardiogenic shock patients. Conclusions: The proportion of elderly patients referred for PCI is increasing. Procedural complications increase with age, and patients presenting with unstable symptoms are at the highest risk. © 2011 Wiley Periodicals, Inc. This work was supported by Blue Cross Blue Shield of Michigan. The authors have no other funding, financial relationships, or conflicts of interest to disclose.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86865/1/20926_ftp.pd

Low-temperature heat transfer mediums for cryogenic applications

Copyright © 2023 The Author(s). Background: Researchers and industrialists have grown interested in cryogenic technologies over the years. Cryogenic heat transfer has enabled new applications due to material properties and behaviour at very low temperatures. This domain is still underdeveloped and unfamiliar in various applications. Methods: This work discusses the recent progress on cryogenic mediums and their respective use in different heat transfer applications. After identifying what is commonly designated as a cryogenic medium, i.e., those with a boiling point below -150 °C, the different characteristics and features of such mediums are critically discussed. Significant findings: Liquid He and N2 were found to be the most used cryogenic mediums, mainly due to the very low temperature attained by liquid He, as the closest to the absolute zero, along with the low cost and high availability of liquid N2. The use of liquid-phase cryogenic in a single-phase state was found to be the most common application method. Two-phase applications of the cryogenic medium are mainly for use in a heat pipe, in which both latent and sensible heat is utilized. Cryogenic mediums are essential for critical and niche applications such as in aerospace, superconductivity, advanced machining and manufacturing methods, and more critically in many healthcare applications and advanced scientific research.Air Products PLC under grant agreement: 216-206-P-F

Orientation dependence of the elastocaloric effect in Ni54Fe19Ga27 ferromagnetic shape memory alloy

The crystallographic anisotropy of elastocaloric effect (ECE) and relative cooling power (RCP) in Ni54Fe19Ga27 shape memory alloy single crystals are studied via compression tests. Single crystals are studied along the [001], [123], and [011] austenite directions and yield different ECE behaviors and maximum RCPs for various strain levels. A thermodynamic framework using the Helmholtz free energy is employed to analyze the total entropy change as a function of strain. Thermodynamic losses are computed from the mechanical hysteresis of superelasticity experiments to quantify the strain dependent RCP. It is found that the [001] orientation generates the highest maximal RCP of 738 J kg−1 when unloaded from 200 MPa. This is attributed mainly to the large superelastic temperature window of 45 K. However, loading the crystals to stresses higher than 200 MPa causes a multistep transformation in the [011] direction, thus reducing the alloy's overall RCP by 135 J kg−1. This is a consequence of the negative entropy change and large transformation hysteresis generated by the second‐stage transformation in the [011] direction. Interestingly, if only the first‐stage transformation in [011] is employed for the ECE, the [011] direction yields the highest RCP compared to [001] and [123] for any strain up to 3.5%

Organocatalytic enantioselective Friedel-Crafts alkylation of 1-naphthol derivatives and activated phenols with ethyl trifluoropyruvate

An organocatalytic enantioselective Friedel-Crafts alkylation of a series of substituted 1‐naphthol derivatives and activated phenols with ethyl trifluoropyruvate, catalyzed by a quinine‐derived squaramide, is presented. Good yields and high to excellent enantioselectivities of the Friedel-Crafts alkylation products were obtained