Nagel scaling and relaxation in the kinetic Ising model on a n-isotopic chain

The kinetic Ising model on a n-isotopic chain is considered in the framework of Glauber dynamics. The chain is composed of N segments with n sites, each one occupied by a different isotope. Due to the isotopic mass difference, the n spins in each segment have different relaxation times in the absence of the interactions, and consequently the dynamics of the system is governed by multiple relaxation mechanisms. The solution is obtained in closed form for arbitrary n, by reducing the problem to a set of n coupled equations, and it is shown rigorously that the critical exponent z is equal to 2. Explicit results are obtained numerically for any temperature and it is also shown that the dynamic susceptibility satisfies the new scaling (Nagel scaling) proposed for glass-forming liquids. This is in agreement with our recent results (L. L. Goncalves, M. Lopez de Haro, J. Taguena-Martinez and R. B. Stinchcombe, Phys. Rev. Lett. 84, 1507 (2000)), which relate this new scaling function to multiple relaxation processes.Comment: 4 pages, 2 figures, presented at Ising Centennial Colloquium, to be published in the Proceedings (Brazilian Journal of Physics.

Qualitative study in Loop Quantum Cosmology

This work contains a detailed qualitative analysis, in General Relativity and in Loop Quantum Cosmology, of the dynamics in the associated phase space of a scalar field minimally coupled with gravity, whose potential mimics the dynamics of a perfect fluid with a linear Equation of State (EoS). Dealing with the orbits (solutions) of the system, we will see that there are analytic ones, which lead to the same dynamics as the perfect fluid, and our goal is to check their stability, depending on the value of the EoS parameter, i.e., to show whether the other orbits converge or diverge to these analytic solutions at early and late times.Comment: 12 pages, 7 figures. Version accepted for publication in CQ

Illiberal and irrational? Trump and the challenge of liberal modernity in US foreign policy

Building on a growing body of literature on the application of Morgenthau’s ethics to post-Cold War US foreign policy, this article applies Morgenthau’s concept of irrationality to Trump’s foreign policy. Based on this application, the article highlights the limit of rationality in Morgenthau’s theoretical analysis. Specifically, the article argues, pace neo-realist critiques of ‘liberal hegemony’, that Trump reveals an empirical puzzle: US foreign policy can be both irrational and illiberal simultaneously in the pursuit of nationalistic universalism. This is the case, the article argues, because nationalistic universalism in Morgenthau’s analysis is not rooted in liberalism per se but the dynamics of liberal modernity. The Trump puzzle thus reveals an on-going tension between rationality and liberal modernity in Morgenthau’s theoretical analysis: rationality offers an insufficient tool to take upon the challenge of liberal modernity from which Trump’s nationalistic universalism stems. This, the article concludes, leaves Morgenthau’s concept of interest ‘defined in terms of power’ open to misappropriation to ends contrary to their original aim: furthering nationalistic universalism, rather than limiting power. Keywords irrationality, Morgenthau, Trump, US foreign polic

Multicomponent fluids of hard hyperspheres in odd dimensions

Mixtures of hard hyperspheres in odd space dimensionalities are studied with an analytical approximation method. This technique is based on the so-called Rational Function Approximation and provides a procedure for evaluating equations of state, structure factors, radial distribution functions, and direct correlations functions of additive mixtures of hard hyperspheres with any number of components and in arbitrary odd-dimension space. The method gives the exact solution of the Ornstein--Zernike equation coupled with the Percus--Yevick closure, thus extending to arbitrary odd dimension the solution for hard-sphere mixtures [J. L. Lebowitz, Phys.\ Rev.\ \textbf{133}, 895 (1964)]. Explicit evaluations for binary mixtures in five dimensions are performed. The results are compared with computer simulations and a good agreement is found.Comment: 16 pages, 8 figures; v2: slight change of notatio

Bringing Morgenthau's ethics in: pluralism, incommensurability and the turn from fragmentation to dialogue in IR

Why did IR pluralism end with so many incommensurable camps? (How) can IR be demarcated as a discipline where these camps can find common ground for dialogue without glossing over theoretical pluralism? To answer the first question, the paper argues that Morgenthau’s critique of IR as social science can explain the proliferation of camps in IR pluralism that are incommensurable and cannot engage in dialogue. By transcending the dilemma of politics as highlighted in Morgenthau’s critique of social science, theories today are ideological camps that bestow on morality an ideological function that justifies their powers-that-be that serve particular means/ends hierarchies. This leads to the proliferation of empirical causal analyses that cannot be debated, since they rely on political interests that theory ideologically justifies and offers internal validation. To avoid this problem, the paper answers the second question by proposing to demarcate the discipline through Morgenthau’s concept of ‘interest defined as power’. It argues that demarcating the discipline on the basis of this concept opens room for engaging in dialogue in IR through leaving open the normative debate of means and ends, and thus acts as a bulwark against the proliferation of ideological camps, while promoting theoretical pluralism. Keywords Classical realism, dialogue, fragmentation, incommensurability, Hans Morgenthau, IR pluralis

Giant Angiolymphoid Hyperplasia with Eosinophilia on the Chest

Angiolymphoid hyperplasia with eosinophilia is a rare vascular proliferation characterized by single or multiple purplish, brownish papules and subcutaneous nodules, sometimes associated with pain or pruritus. This rare benign process occurs with a female predominance. Approximately 85% of the lesions occur in the skin of the head and neck; most of them are around the ear or on the forehead or scalp. Whether angiolymphoid hyperplasia with eosinophilia represents a benign neoplasm or an unusual reaction to varied stimuli, including trauma, the etiology remains unclear. Histopathologically, the lesions consist of a proliferation of blood vessels of variable size lined by large epithelioid endothelial cells and a variable inflammatory infiltrate of lymphocytes and eosinophils, sometimes with lymphoid follicle formation. The lesion is benign but may be persistent and is difficult to eradicate. We report on a case of a 58-year-old Caucasian man who presented a purplish pink dome-shaped tumor of size up to 8 cm in diameter located on the chest. We emphasize this case considering the unusual dimensions of the lesion (8 cm diameter) and the atypical location on the chest

Quasar 3C 298: a test-case for meteoritic nanodiamond 3.5 µm emission

Aims. We calculate the dust emission expected at 3.43 and 3.53 µm if meteoritic (i.e. hydrogenated) nanodiamonds are responsible for most of the far-UV break observed in quasars. Methods. We integrate the UV flux that hydrogenated nanodiamonds must absorb to reproduce the far-UV break. Based on laboratory spectra of H-terminated diamond surfaces, we analyse the radiative energy budget and derive theoretically the IR emission profiles expected for possible C-H surface stretch modes of the diamonds. Results. Using as test case a spectrum of 3C 298 provided by the Spitzer Observatory, we do not find evidence of these emission bands. Conclusions. While diamonds without surface adsorbates remain a viable candidate for explaining the far-UV break observed in quasars, hydrogenated nanodiamonds appear to be ruled out, as they would give rise to IR emission bands, which have not been observed so far