External Intervention and the Duration of Civil Wars

This paper examines the effect of external intervention on civil war duration from the years 1946-2002. Based on the logic that intervention causes a distortion of the bargaining process in civil wars, it is hypothesized that intervention leads to increased civil war duration. This hypothesis is tested using linear regression analysis, which finds a positive, significant relationship between intervention and civil war duration. Considered in the context of previous literature, it is concluded that in addition to the distorting effect intervention appears to have on the bargaining process, this result may have been informed by the presence of competitive intervention, rival intervention, and interventions by states with an independent agenda. This research provides further evidence of the conflict lengthening effect of intervention, while tracing a common explanation based in the bargaining model of war throughout the various perspectives in the literature

Active Resistors: The Women of Post-Revolution Iran

In this paper, I challenge the notion that Muslim or Middle Eastern women are passive acceptors of discrimination. After examining how Iranian women resisted governmental discrimination following the 1979 Iranian Revolution, I consider a number of factors that may have led to the reversal of some of these discriminatory policies in the 1990’s. How much of an effect did women’s demands for equality have on the government’s decisions? This question of effectiveness introduces a longtime debate between Islamic feminists, who advocate for working with the theocratic government and using Islam to frame their demands for equality, and secular feminists, who advocate for using legal and political systems to reach a similar goal. Following a critical evaluation of each approach, the question evolves into whether a radical or a resonant frame is more effective. After taking into account the masculinity and power complexes of government leaders, I suggest that a resonant approach is in a unique position to successfully manipulate the government, which could lead to the reversal of discriminatory policies. However, the women’s rights movement will be most powerful if the two sides put aside their differences and unite in the fight against discrimination

The Proximity-Based Effect of Terrorism on Countries\u27 Economies

In this paper, I explore the effect that proximity to terrorist-controlled areas has on countries’ economies. I posit that there exists a correlation between the aforementioned proximity and GDP growth rates, and hypothesize that the closer a country is to an area with high levels of terrorism, the more likely it is that its economy will be negatively affected. I begin by examining the nature of the correlation between terrorism and economic growth; following this, I explore the direct ways in which terrorism affects economic growth. Next, I delve into the recent economic history of countries around three areas: the Nigeria area, the Afghanistan-Pakistan area, and the Iraq-Syria area. From my examinations of the GDP growth rates of the countries around these areas, I find no uniform relationship between the countries’ proximity to their respective areas and their GDP growth rates. To help explain this apparent lack of correlation, I look at other factors that influence GDP growth rates and note that these factors may be overshadowing the effects of terrorism. I conclude that there is no uniform relationship between a country’s proximity to high levels of terrorism and its GDP; although terrorism can have effects on countries’ economies, those effects are often negligible compared to other economic factors

The main transition in the Pink membrane model: finite-size scaling and the influence of surface roughness

We consider the main transition in single-component membranes using computer simulations of the Pink model [D. Pink {\it et al.}, Biochemistry {\bf 19}, 349 (1980)]. We first show that the accepted parameters of the Pink model yield a main transition temperature that is systematically below experimental values. This resolves an issue that was first pointed out by Corvera and co-workers [Phys. Rev. E {\bf 47}, 696 (1993)]. In order to yield the correct transition temperature, the strength of the van der Waals coupling in the Pink model must be increased; by using finite-size scaling, a set of optimal values is proposed. We also provide finite-size scaling evidence that the Pink model belongs to the universality class of the two-dimensional Ising model. This finding holds irrespective of the number of conformational states. Finally, we address the main transition in the presence of quenched disorder, which may arise in situations where the membrane is deposited on a rough support. In this case, we observe a stable multi-domain structure of gel and fluid domains, and the absence of a sharp transition in the thermodynamic limit.Comment: submitted to PR

Getting More from Pushing Less: Negative Specific Heat and Conductivity in Non-equilibrium Steady States

For students familiar with equilibrium statistical mechanics, the notion of a positive specific heat, being intimately related to the idea of stability, is both intuitively reasonable and mathematically provable. However, for system in non-equilibrium stationary states, coupled to more than one energy reservoir (e.g., thermal bath), negative specific heat is entirely possible. In this paper, we present a ``minimal'' system displaying this phenomenon. Being in contact with two thermal baths at different temperatures, the (internal) energy of this system may increase when a thermostat is turned down. In another context, a similar phenomenon is negative conductivity, where a current may increase by decreasing the drive (e.g., an external electric field). The counter-intuitive behavior in both processes may be described as `` getting more from pushing less.'' The crucial ingredients for this phenomenon and the elements needed for a ``minimal'' system are also presented.Comment: 14 pages, 3 figures, accepted for publication in American Journal of Physic

Unmanned extravehicular environments operation qualification test of the Gemini ELSS /Extravehicular Life Support System/ Test plan

Space environment and failure mode simulation for unmanned qualification testing of Gemini Extravehicular Life Support System /ELSS

Theoretical investigation of finite size effects at DNA melting

We investigated how the finiteness of the length of the sequence affects the phase transition that takes place at DNA melting temperature. For this purpose, we modified the Transfer Integral method to adapt it to the calculation of both extensive (partition function, entropy, specific heat, etc) and non-extensive (order parameter and correlation length) thermodynamic quantities of finite sequences with open boundary conditions, and applied the modified procedure to two different dynamical models. We showed that rounding of the transition clearly takes place when the length of the sequence is decreased. We also performed a finite-size scaling analysis of the two models and showed that the singular part of the free energy can indeed be expressed in terms of an homogeneous function. However, both the correlation length and the average separation between paired bases diverge at the melting transition, so that it is no longer clear to which of these two quantities the length of the system should be compared. Moreover, Josephson's identity is satisfied for none of the investigated models, so that the derivation of the characteristic exponents which appear, for example, in the expression of the specific heat, requires some care

Vacancy-assisted domain-growth in asymmetric binary alloys: a Monte Carlo study

A Monte Carlo simulation study of the vacancy-assisted domain-growth in asymmetric binary alloys is presented. The system is modeled using a three-state ABV Hamiltonian which includes an asymmetry term, not considered in previous works. Our simulated system is a stoichiometric two-dimensional binary alloy with a single vacancy which evolves according to the vacancy-atom exchange mechanism. We obtain that, compared to the symmetric case, the ordering process slows down dramatically. Concerning the asymptotic behavior it is algebraic and characterized by the Allen-Cahn growth exponent x=1/2. The late stages of the evolution are preceded by a transient regime strongly affected by both the temperature and the degree of asymmetry of the alloy. The results are discussed and compared to those obtained for the symmetric case.Comment: 21 pages, 9 figures, accepted for publication in Phys. Rev.

Quantum Fluctuations Driven Orientational Disordering: A Finite-Size Scaling Study

The orientational ordering transition is investigated in the quantum generalization of the anisotropic-planar-rotor model in the low temperature regime. The phase diagram of the model is first analyzed within the mean-field approximation. This predicts at $T=0$ a phase transition from the ordered to the disordered state when the strength of quantum fluctuations, characterized by the rotational constant $\Theta$, exceeds a critical value $\Theta_{\rm c}^{MF}$. As a function of temperature, mean-field theory predicts a range of values of $\Theta$ where the system develops long-range order upon cooling, but enters again into a disordered state at sufficiently low temperatures (reentrance). The model is further studied by means of path integral Monte Carlo simulations in combination with finite-size scaling techniques, concentrating on the region of parameter space where reentrance is predicted to occur. The phase diagram determined from the simulations does not seem to exhibit reentrant behavior; at intermediate temperatures a pronounced increase of short-range order is observed rather than a genuine long-range order.Comment: 27 pages, 8 figures, RevTe