Volatility, Financial Constraints, and trade

We construct a dynamic monopolistic competition model with heterogeneous firms to study the links between firms’ earnings volatility, the degree of financial constraints that they face, their survival probabilities, and their export market participation decisions. Our model predicts that more volatile firms are more likely to face financial constraints and to go bankrupt, need to be more productive to stay in the market, and are more likely to enter export markets. A further implication is that through market diversification, exports tend to stabilize firms’ total sales. We test these predictions, using a panel of 9292 UK manufacturing firms over the period 1993-2003. The data provide strong support to our model.Firm-level volatility; Financial constraints; Firm survival; Exports

An epiperimetric inequality approach to the regularity of the free boundary in the Signorini problem with variable coefficients

In this paper we establish the $C^{1,\beta}$ regularity of the regular part of the free boundary in the Signorini problem for elliptic operators with variable Lipschitz coefficients. This work is a continuation of the recent paper [GSVG14], where two of us established the interior optimal regularity of the solution. Two of the central results of the present work are a new monotonicity formula and a new epiperimetric inequality.Comment: 40 page

Plasmon Generation through Electron Tunneling in Graphene

The short wavelength of graphene plasmons relative to the light wavelength makes them attractive for applications in optoelectronics and sensing. However, this property limits their coupling to external light and our ability to create and detect them. More efficient ways of generating plasmons are therefore desirable. Here we demonstrate through realistic theoretical simulations that graphene plasmons can be efficiently excited via electron tunneling in a sandwich structure formed by two graphene monolayers separated by a few atomic layers of hBN. We obtain plasmon generation rates of $\sim10^{12}-10^{14}/$s over an area of the squared plasmon wavelength for realistic values of the spacing and bias voltage, while the yield (plasmons per tunneled electron) has unity order. Our results support electrical excitation of graphene plasmons in tunneling devices as a viable mechanism for the development of optics-free ultrathin plasmonic devices.Comment: 15 pages, 11 figures, 92 reference

Development by Mechanochemistry of La0.8Sr0.2Ga0.8Mg0.2O2.8 Electrolyte for SOFCs

In this work, a mechanochemical process using high-energy milling conditions was employed to synthesize La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) powders from the corresponding stoichiometric amounts of La2O3, SrO, Ga2O3, and MgO in a short time. After 60 min of milling, the desired final product was obtained without the need for any subsequent annealing treatment. A half solid oxide fuel cell (SOFC) was then developed using LSGM as an electrolyte and La0.8Sr0.2MnO3 (LSM) as an electrode, both obtained by mechanochemistry. The characterization by X-ray diffraction of as-prepared powders showed that LSGM and LSM present a perovskite structure and pseudo-cubic symmetry. The thermal and chemical stability between the electrolyte (LSGM) and the electrode (LSM) were analyzed by dynamic X-ray diffraction as a function of temperature. The electrolyte (LSGM) is thermally stable up to 800 and from 900 °C, where the secondary phases of LaSrGa3O7 and LaSrGaO4 appear. The best sintering temperature for the electrolyte is 1400 °C, since at this temperature, LaSrGaO4 disappears and the percentage of LaSrGa3O7 is minimized. The electrolyte is chemically compatible with the electrode up to 800 °C. The powder sample of the electrolyte (LSGM) at 1400 °C observed by HRTEM indicates that the cubic symmetry Pm-3m is preserved. The SOFC was constructed using the brush-painting technique; the electrode-electrolyte interface characterized by SEM presented good adhesion at 800 °C. The electrical properties of the electrolyte and the half-cell were analyzed by complex impedance spectroscopy. It was found that LSGM is a good candidate to be used as an electrolyte in SOFC, with an Ea value of 0.9 eV, and the LSM sample is a good candidate to be used as cathode

Transitive phrasal verbs with the particle "out": A lexicon-grammar analysis

International audienceUsing a lexicon-grammar approach developed by Maurice Gross (1992), this project involved systematically mapping the structural properties of over 550 transitive phrasal verbs with the particle "out", "PV out". The data is analyzed in terms of two main tables or matrices. The first table illustrates the morpho-syntactic properties of purely simple "PV out" expressions, like "freak out the kid" ↔ "freak the kid out". The second table illustrates the morpho-syntactic combinations of complex "PV out" expressions, as in "take the boxer out of the fight". The research shows that "PV out" expressions may involve up to 25 syntactic features, including N 2 promotion, as in "The girl spilled the water out of the glass" → "The girl spilled the glass out", complex-neutral constructions, like "The water spilled out of the glass", and reversed constructions, like "The company farmed the oil out of the land" →"The company farmed the land out of oil". The research shows that these syntactic combinations are highly lexical in that a unique combination of features applies to individual phrasal verbs

Saving Rawlsian Selfhood

Often lauded as one of the most rigorous contributions to American political philosophy during the post-war period, John Rawls\u27 Theory of Justice is a natural starting point for those interested in liberalism. In light of commitments made by Rawls to a Kantian ideal of individualism; however, especially for those concerned with selfhood, at times Theory also proves to be an obstacle to overcome. Communitarians, critical race theorists, and liberals alike have viewed Rawls\u27 conception of selfhood from his early work as a holdover from a bygone Enlightenment era to be abandoned at all costs. That response, however, is premature as Rawls\u27 Theory nevertheless possesses a stronger justification for its conception of selfhood than the politically free-standing model adopted by the later Rawls. This thesis re-imagines that longstanding, often tacitly assumed, vision of self-hood which is at the core of many forms of liberalism by finding a workable account of selfhood that is compatible with the overall project of Rawlsian liberalism presented in Theory, yet remains sensitive to its critics; a project which proves essential for reconstructions of liberalism or any Rawlsian derivative thereof