T-Dualities and Doubled Geometry of the Principal Chiral Model

The Principal Chiral Model (PCM) defined on the group manifold of SU(2) is here investigated with the aim of getting a further deepening of its relation with Generalized and Doubled Geometry. A one-parameter family of equivalent Hamiltonian descriptions is introduced, and cast into the form of Born geometries. Then O(3,3) duality transformations of the target phase space are performed and we show that the resulting dual models are defined on the group SB(2,C) which is the Poisson-Lie dual of SU(2) in the Iwasawa decomposition of the Drinfel'd double SL(2, C). Moreover, starting from the Lagrangian approach, a new kind of duality is found between the SU(2) PCM and the natural one defined on SB(2,C) which is not an isometry of the target phase space. A parent action with doubled degrees of freedom and configuration space SL(2, C) is then defined that reduces to either one of the dually related models, once suitable constraints are implemented.Comment: 41 pages, revised version published in JHE

analytical stiffness matrix for curved metal wires

Abstract The paper presents an analytic stiffness matrix for curved thin metal wires, derived by the application of the second Castigliano's Theorem. The matrix accounts both bending and axial stiffness contributions in plane. The beam geometry is described by a cubic polynomial function of the curvature radius with a monotonical attitude angle as the independent variable. The solution proposed if fully analytical although a consistent number of adding factors appear. Some test cases are discussed and compared with Finite Element solutions, formed by a plentiful assembly of straight beams

Energy price increases and mitigation policies: Redistributive effects on Italian households

Since the second half of 2021, there has been a sharp increase in the prices of energy goods (electricity, heating gas, fuels) as well as of food, leading to inflation rates never experienced in Italy in the last forty years. Such high inflation rates prompted the Italian government to take measures to curb the prices of energy products, to increase social bonuses on electricity and gas bills, and to provide one-off allowances to households. The crucial question is what impact the price increases have had on households and whether the measures taken have protected the household sector from these increases. Therefore, we perform a microsimulation exercise on the period July 2021-March 2023 to quantify the effects of the price increases and of the measures on household expenditure and income. Our results indicate that the regressive impact of price increases was mitigated by the price containment measures due to their progressive nature and that the contribution of one-off allowances and social bonuses was very relevant. In 2022, the year in which households benefitted from the measures for twelve months, the fiscal policy interventions also succeeded in reducing inequality, the at-risk-of-poverty rate and energy poverty

NCLs and ER: A stressful relationship.

The Neuronal Ceroid Lipofuscinoses (NCLs, Batten disease) are a group of inherited neurodegenerative disorders with variable age of onset, characterized by the lysosomal accumulation of autofluorescent ceroid lipopigments. The endoplasmic reticulum (ER) is a critical organelle for normal cell function. Alteration of ER homeostasis leads to accumulation of misfolded protein in the ER and to activation of the unfolded protein response. ER stress and the UPR have recently been linked to the NCLs. In this review, we will discuss the evidence for UPR activation in the NCLs, and address its connection to disease pathogenesis. Further understanding of ER-stress response involvement in the NCLs may encourage development of novel therapeutical agents targeting these pathogenic pathways

Anomalies and Tadpoles in Open/Closed String Duality

We discuss the role played by the divergences appearing in the interaction between a fractional D3 brane dressed with an SU(N) gauge field and a stack of N fractional D3 branes on the orbifolds C^2/Z_2 and C^3/(Z_2 x Z_2). In particular we show that the logarithmic divergences in the closed string channel, interpreted as due to twisted massless tadpoles, are mapped, under open/closed string duality, in the logarithmic ones in the open string channel, due to the massless states circulating in the annulus diagram and corresponding to the one-loop divergences that one finds in the gauge theory living in the world volume of the brane. This result provides a quantitative evidence of why the chiral and scale anomalies of the supersymmetric and non conformal gauge theories supported by the world volume of the branes can be inferred from supergravity calculations.Comment: LaTeX, 8 pages. Contribution to the proceedings of the workshop of the RTN Network "The quantum structure of space-time and the geometric nature of fundamental interactions", Copenhagen, September 200

Short-term household income mobility before and after the Great Recession: A four-country study

This paper analyses short-term intra-generational income mobility in France, Italy, Spain and the UK by exploiting the longitudinal component of EU-SILC for the periods 2005-2008 and 2012-2015. We investigate whether and to what extent the ability of households to move along the income distribution changed after the 2008 crisis and whether heterogeneities among countries exist. For this purpose, we employ mobility indexes and transition matrices as well as estimation of a 2SLS regression and of a dynamic ordered probit with random effects. Overall, indexes and transition matrices point to a decrease of mobility in the aftermath of the crisis. The econometric analyses suggest both the existence of a convergence process of incomes and state dependence of current and lagged income in both periods. We also observe sluggish income convergence and lower upward mobility in the second period. Among the microeconomic drivers, education and employment status are positive determinants of mobility. Finally, our results confirm crosscountry heterogeneity

Atmospheric Pressure Non-thermal Plasma for Air Purification: Ions and Ionic Reactions Induced by dc+ Corona Discharges in Air Contaminated with Acetone and Methanol

Atmospheric pressure mass spectrometry (APCI-MS) was used to investigate the positive ions in air containing acetone (A), methanol (M) and mixtures thereof (A + M), subjected to +dc corona discharges. The results of experiments with isotopically labelled analogues, perdeuterated acetone Adeu and methanol Mdeu, and relevant thermochemical data found in the literature allowed us to identify the main ionic reactions occurring in single component systems (A or M) and in binary mixtures (A + M). It is concluded that, thanks to its significantly higher proton affinity, A is very efficient in quenching M-derived ions at atmospheric pressure. These conclusions provide a rationale for interpreting the results of a parallel investigation on the reciprocal effects of M and A when treated together in air at atmospheric pressure with +dc corona in a non-thermal plasma reactor developed previously in our laboratory. Specifically, we observed a marked drop in the degradation efficiency of methanol when it was treated in the presence of an equivalent amount of acetone. This effect is attributed to acetone interfering with ion-initiated degradation processes of methanol, and supports the conclusion\ua0that ions and ionic reactions are important in dc+ corona induced oxidation of volatile organic pollutants in air

Collateral Requirements of SMEs: The Evidence from Less–Developed Countries

A rating trigger is a particular type of debt covenant that mandates the borrower to maintain its own credit rating above a certain rating threshold, requiring in the event of a rating downgrade the adoption of specific enforceable actions aimed at securing the lender claims from the borrower's higher risk level. Rating triggers lower the cost of borrowing capital, but in case they are activated they exacerbate the borrower's need for liquidity just in the moment when its credit risk is higher, making the borrower's default more likely to occur. Despite the potential threat posed by rating triggers on debt markets, these contractual devices remain almost unregulated both in the U.S. and in Europe. The purpose of this paper is first to analyze the effects rating triggers can have on overall market risk and second to assess the proliferation of rating triggers among large U.S. companies in order to ensure whether these contractual devices need a stricter regulation. The article is divided in two parts. From section 2 to 5, I provide an overview on the different types of triggers and analyze the rationale behind their use in terms of advantages and disadvantages for both issuers and investors. From section 6 to 9 I perform an empirical analysis by assessing the rating triggers that have been used by Dow Jones Industrial Average index companies. I then examine the correlation between the use of rating triggers and the companies’ risk profiles by measuring their credit ratings and their Altman’s Z-Scores in order to find out whether triggers are mostly used by risky companies, capable of being impaired by the triggers’ activation and thus posing a threat to market stability. Then in section 10 I draw the conclusions suggesting the introduction by U.S. and European regulators of a specific duty to disclose all the rating triggers that listed companies include every year in bond indentures and in financial contract