The Limits of Custodial Symmetry

We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Zbb coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the top quark) to the particle content of the standard model in order to implement an O(4) x U(1)_X = SU(2)_L x SU(2)_R x P_{LR} x U(1)_X symmetry that protects the Zbb coupling. This symmetry is softly broken to the gauged SU(2)_L x U(1)_Y electroweak symmetry by a Dirac mass M for the new doublet; adjusting the value of M allows us to explore the range of possibilities between the O(4)-symmetric (M to 0) and standard-model-like (M to infinity) limits. In this simple model, we find that the experimental limits on the Zbb coupling favor smaller M while the presence of a potentially sizable negative contribution to T strongly favors large M. A fit to all precision electroweak data shows that the heavy partner of the top quark must be heavier than about 3.4 TeV, making it difficult to search for at LHC. This result demonstrates that electroweak data strongly limits the amount by which the custodial symmetry of the top-quark mass generating sector can be enhanced relative to the standard model. Using an effective field theory calculation, we illustrate how the leading contributions to alpha T, alpha S and the Zbb coupling in this model arise from an effective operator coupling right-handed top-quarks to the Z-boson, and how the effects on these observables are correlated. We contrast this toy model with extra-dimensional models in which the extended custodial symmetry is invoked to control the size of additional contributions to alpha T and the Zbb coupling, while leaving the standard model contributions essentially unchanged.Comment: 19 pages, 11 eps figures. Typos correcte

A circular dichroism study of the protective role of polyphosphoesters polymer chains in polyphosphoester‐myoglobin conjugates

Protein-polymer conjugates are a blooming class of hybrid systems with high biomedical potential. Despite a plethora of papers on their biomedical properties, the physical–chemical characterization of many protein-polymer conjugates is missing. Here, we evaluated the thermal stability of a set of fully-degradable polyphosphoester-protein conjugates by variable temperature circular dichroism, a common but powerful technique. We extensively describe their thermodynamic stability in different environments (in physiological buffer or in presence of chemical denaturants, e.g., acid or urea), highlighting the protective role of the polymer in preserving the protein from denaturation. For the first time, we propose a simple but effective protocol to achieve useful information on these systems in vitro, useful to screen new samples in their early stages

The Role of Maintenance Operator in Industrial Manufacturing Systems: Research Topics and Trends

Maintenance contributes to gaining high business performance, guarantees system availability and reliability as well as safe and sustainable operations. Maintenance activity effectiveness depends on competences and the skills of operators whose performance strongly affects maintenance and production operations. The research field of human issues in industrial maintenance was deeply addressed in the literature; however, the current industrial paradigm, which focusses on the integration of new technologies in conventional manufacturing operations to support human performance, sheds light on new challenges for enterprises and opportunities for research in this field. While some literature reviews in the field of human errors and human factors are available, no study investigated the main topics, research trends and challenges related to the role of maintenance operators in manufacturing systems. This paper addresses the current state-of-the-art role of maintenance operators in manufacturing systems, providing an overview of the main studies. A systematic literature review was carried out to identify significant papers. Then, a topic modelling algorithm was used to detect the main topics of the selected papers to provide the research trends of the subject. The identified topics provided interesting research insights on the human role in industrial maintenance. Research trends and further research opportunities were defined

Maintenance deep transcranial magnetic stimulation sessions are associated with reduced depressive relapses in patients with unipolar or bipolar depression

Introduction: Deep transcranial magnetic stimulation (dTMS) is a new form of TMS allowing safe stimulation of deep brain regions. The objective of this preliminary study was to assess the role of dTMS maintenance sessions in protecting patients with bipolar disorder (BD) or recurrent major depressive disorder (MDD) from developing depressive or manic relapses in a 12-month follow-up period. Methods: Twenty-four drug-resistant patients with a current depressive episode and a diagnosis of MDD or BD have been enrolled in the study. All the participants underwent daily dTMS sessions for 4 weeks. One group (maintenance - M group) received additional maintenance dTMS sessions weekly or twice a week. Results: After the first dTMS cycle, a significant reduction of Hamilton Depression Rating Scale (HDRS) scores was observed in all participants. Subsequently, the HDRS mean scores did not significantly change over time in the M group, while it significantly increased in the non-M-group after 6 and 12 months. Discussion: This study confirms previous evidence of a positive therapeutic effect of dTMS on depressive symptoms and suggests that, after recovery from acute episodes, maintenance dTMS sessions may be helpful in maintaining euthymia in a 12-month follow-up period

Paramagnetic defects in polycrystalline zirconia: An EPR and DFT study

The paramagnetic defects present in pristine zirconium dioxide (ZrO2) and those formed upon reductive treatments (either annealing or UV irradiation in H-2) are described and rationalized by the joint use of electron paramagnetic resonance (EPR) and DFT supercell calculations. Three types of Zr3+ reduced sites have been examined both in the bulk of the solid (one center) and at the surface (two centers). Trapping electron centers different from reduced Zr ions are also present, whose concentration increases upon annealing. A fraction of these sites are paramagnetic showing a symmetric signal at g = 2.0023, but the majority of them are EPR silent and are revealed by analysis of electron transfer from the reduced solid to oxygen. The presence of classic F-type centers (electrons in bulk oxygen vacancies) is disregarded on the basis of the g-tensor symmetry. This is expected, on the basis of theoretical calculations, to be anisotropic and thus incompatible with the observed signal. In general terms, ZrO2 has Some properties similar to typical reducible oxides, such as TiO2 and CeO2 (excess electrons stabilized at cationic sites), but it is much more resistant to reduction than this class of materials. While point defects in doped (Y3+, Ca2+) ZrO2 materials have been widely investigated for their role as ionic conductors, the defectivity of pristine ZrO2 is much less known; this paper presents a thorough analysis of this phenomenon

Three-dimensional hydrogeological parametrization using sparse piezometric data

When modelling contamination transport in the subsurface and aquifers, it is crucial to assess the heterogeneities of the porous medium, including the vertical distribution of the aquifer parameter. This issue is generally addressed thanks to geophysical investigations. As an alternative, a method is proposed using estimated hydraulic parameters from a 2D calibrated flow model (solely reliant on piezometric series) as parametrization constraints for a 3D hydrogeological model. The methodology is tested via a synthetic model, ensuring full knowledge and control of its structure. The synthetic aquifer is composed of five lithofacies, distributed according to a sedimentary pattern, and functions in an unconfined regime. The level of heterogeneity for hydraulic conductivity spans 3 orders of magnitude. It provides the piezometric chronicles used to inverse 2D flow parameter fields and the lithological logs used to interpolate the 3D lithological model. Finally, the parameters of each facies (hydraulic conductivity and porosity) are obtained through an optimization loop, which minimizes the difference between the 2D calibrated transmissivity and the transmissivity computed with the estimated 3D facies parameters. The method estimates values close to the known parameters, even with sparse piezometric and lithological data sampling. The maximal discrepancy is 45 % of the known value for the hydraulic conductivity and 6 % for the porosity (mean error 26 % and 3 %, respectively). Although the methodology does not prevent interpolation errors, it succeeds in reconstructing flow and transport dynamics close to the control data. Due to the inherent limitations of the 2D inversion approach, the method only applies to the saturated zone at this point.</p

Hemostatic function in young subjects with central obesity: relationship with left ventricular function

This study was designed to evaluate coagulation and fibrinolysis activity and their relationship with left ventricular function in young obese subjects with central fat distribution. We assessed coagulation and fibrinolysis activity by evaluation of factor VII activity, fibrinogen and plasminogen, plasminogen activator inhibitor (PAI), and tissue plasminogen activator antigen basally (tPA1) and after venous occlusion (tPA2). These measures were evaluated in young (< 40 years) obese subjects with central fat distribution (n = 19) and in comparable lean subjects (n = 20). Blood glucose, triglycerides, total and high-density lipoprotein (HDL) cholesterol, apolipoprotein (apo) A1 and apo B, fasting immunoreactive insulin, and lipoprotein(a) levels were also measured by current methods. Left ventricular ejection fraction (LVEF) and peak filling rate (PFR) determined by radionuclide angiocardiography and left ventricular mass (LVM) and LVM indexed for body height (LVM/H) determined by echocardiographic study were calculated. Central obesity was evaluated by the waist to hip ratio (WHR) according to the criteria of the Italian Consensus Conference of Obesity. Factor VII (P < .001), fibrinogen (P < .001), plasminogen (P < .001), PAI activity (P < .001), tPA1 (P < .02), fasting blood glucose (P < .01), apo B (P < .02), and immunoreactive insulin (P < .01) were significantly higher in obese than in lean subjects. In contrast, HDL cholesterol (P < .01), tPA2 (P < .01), LVEF (P < .001), and PFR (P < .02) were significantly lower in obese than in lean subjects. In all subjects, WHR correlated directly with fibrinogen and inversely with tPA2; LVEF correlated inversely with tPA1, PAI, and fibrinogen; and PFR correlated inversely with factor VII activity