The Direct Detectability of Giant Exoplanets in the Optical

Motivated by the possibility that a coronagraph will be put on WFIRST/AFTA, we explore the direct detectability of extrasolar giant planets (EGPs) in the optical. We quantify a planet's detectability by the fraction of its orbit for which it is in an observable configuration ($f_\mathrm{obs}$). Using a suite of Monte Carlo experiments, we study the dependence of $f_\mathrm{obs}$ upon the inner working angle (IWA) and minimum achievable contrast ($C_\mathrm{min}$) of the direct-imaging observatory; the planet's phase function, geometric albedo, single-scattering albedo, radius, and distance from Earth; and the semi-major axis distribution of EGPs. We calculate phase functions for a given geometric or single-scattering albedo, assuming various scattering mechanisms. We find that the Lambertian phase function can predict significantly larger $f_\mathrm{obs}$'s with respect to the more realistic Rayleigh phase function. For observations made with WFIRST/AFTA's baseline capabilities ($C_\mathrm{min}\sim10^{-9}$, $\mathrm{IWA}\sim0.2''$), Jupiter-like planets orbiting stars within 10, 30, and 50 parsecs of Earth have volume-averaged observability fractions of ${\sim}$12%, 3%, and 0.5%, respectively. At 10 parsecs, such observations yield $f_\mathrm{obs}>1\%$ for low- to modest-eccentricity planets with semi-major axes in the range ${\sim}2 - 10$ AU. If $C_\mathrm{min}=10^{-10}$, this range extends to ${\sim}35$ AU. We find that, in all but the most optimistic configurations, the probability for detection in a blind search is low (${<}\,5\%$). However, with orbital parameter constraints from long-term radial-velocity campaigns and Gaia astrometry, the tools we develop in this work can be used to determine both the most promising systems to target and when to observe them.Comment: 16 pages, 16 figures. Accepted for publication in Ap

On the notion of linguistic influence in syntax: Evidence from medieval Italo-Romance texts

This paper tackles the topic of Latin influence on Italo-Romance syntax by addressing the question how to combine the analysis of structural data with socio-historical reflections. It views the genre and discourse tradition of a given medieval text as governing the extent to which Latin is used as a model in this text. The paper proposes a methodology which incorporates consideration of the historical, cultural, and sociolinguistic context of language change, focusing on evidence from the development of present participles in Italo-Romance. The main conclusion is that, rather than talking about the general influence of Latin syntax on Italian, we should be examining the influence of particular Latin models on the syntax of different texts written in Italo-Romance varieties in a given historical period

Critical Endpoint and Inverse Magnetic Catalysis for Finite Temperature and Density Quark Matter in a Magnetic Background

In this article we study chiral symmetry breaking for quark matter in a magnetic background, $\bm B$, at finite temperature and quark chemical potential, $\mu$, making use of the Ginzburg-Landau effective action formalism. As a microscopic model to compute the effective action we use the renormalized quark-meson model. Our main goal is to study the evolution of the critical endpoint, ${\cal CP}$, as a function of the magnetic field strength, and investigate on the realization of inverse magnetic catalysis at finite chemical potential. We find that the phase transition at zero chemical potential is always of the second order; for small and intermediate values of $\bm B$, ${\cal CP}$ moves towards small $\mu$, while for larger $\bm B$ it moves towards moderately larger values of $\mu$. Our results are in agreement with the inverse magnetic catalysis scenario at finite chemical potential and not too large values of the magnetic field, while at larger $\bm B$ direct magnetic catalysis sets in.Comment: 6 pages, 2 figure

On the Path Integral Representation for Spin Systems

We propose a classical constrained Hamiltonian theory for the spin. After the Dirac treatment we show that due to the existence of second class constraints the Dirac brackets of the proposed theory represent the commutation relations for the spin. We show that the corresponding partition function, obtained via the Fadeev-Senjanovic procedure, coincides with the one obtained using coherent states. We also evaluate this partition function for the case of a single spin in a magnetic field.Comment: To be published in J.Phys. A: Math. and Gen. Latex file, 12 page

Large isotope effect on TcT_c in cuprates despite of a small electron-phonon coupling

We calculate the isotope coefficients $\alpha$ and $\alpha^\ast$ for the superconducting critical temperature $T_c$ and the pseudogap temperature $T^\ast$ in a mean-field treatment of the t-J model including phonons. The pseudogap phase is identified with the $d$-charge-density wave ($d$-CDW) phase in this model. Using the small electron-phonon coupling constant $\lambda_d \sim 0.02$ obtained previously in LDA calculations in YBa$_2$Cu$_3$O$_7$, $\alpha^{\ast}$ is negative but negligible small whereas $\alpha$ increases from about 0.03 at optimal doping to values around 1 at small dopings in agreement with the general trend observed in many cuprates. Using a simple phase fluctuation model where the $d$-CDW has only short-range correlations it is shown that the large increase of $\alpha$ at low dopings is rather universal and does not depend on the existence of sharp peaks in the density of states in the pseudogap state or on specific values of the phonon cutoff. It rather is caused by the large depletion of spectral weight at low frequencies by the $d$-CDW and thus should also occur in other realizations of the pseudogap.Comment: 8 pages, 5 figures, to be publ. in PR

Effect of resonance decays on hadron elliptic flows

The influence of resonance decays on the elliptic flows of stable hadrons is studied in the quark coalescence model. Although difference between the elliptic flow of pions from resonance decays, except the rho meson, and that of directly produced pions is appreciable, those for other stable hadrons are small. Since there are more pions from the decays of rho mesons than from other resonances, including resonance decays can only account partially the deviation of final pion elliptic flow from the observed scaling of hadron elliptic flows, i.e., the hadron elliptic flow per quark is the same at same transverse momentum per quark. The remaining deviation can be explained by including the effect due to the quark momentum distribution inside hadrons.Comment: 13 pages and 5 figures, version pubblished in PRC, updated references and figure

ADR and a Smile: Neocolonialism and the West\u27s Newest Export in Africa

While the ills of the West\u27s corporatization of the world have long been debated and catalogued, often neglected is the role the law plays in empowering the rich, disenfranchising the poor, and serving as the handmaiden to empire. Since what has been termed the rule of law revival, which saw its genesis sometime in the late 1980s, the adoption of Western legal frameworks to help developing and Third World nations transition and gain access to the ever growing global market has become commonplace. With the coming of the Alternative Dispute Resolution (ADR) revolution during the last few decades, the West has also begun to export its newest soft technology, a form of conflict resolution purportedly based on a harmon[ic] as opposed to an adversarial approach. The question is whether this is really a new product which will promote greater access to justice, or whether this is something more akin to a soft drink company whose vending machines now carry bottled water alongside their familiar carbonated beverages. Is it just a new product in the same corporate machine? Part II of this article will discuss the significance and application of rule of law doctrine and methods of legal reform implemented in developing nations. It will debate some of their positives and negatives, as well as their relationship to the idea of neocolonialism. Part III will describe the exportation of ADR and its interweaving into developing legal systems. As Africa has often been at the forefront of discussions regarding neocolonialism, 2 Part IV will seek to analyze the implementation of a multi-door courthouse in Uganda\u27s Commercial High Court--one which seeks to integrate mandatory mediation with an adopted common law tradition-and how its development was influenced by Western theories of legal reform. It will evaluate the successes and failures of these reforms by judging them on their overarching goals, methods, and results. It will further discuss the use of Local Council Courts (LCCs) as a form of grass roots justice in Uganda, and compare the potential gains and losses of both systems. Part V will explore the need for synthesis between modem legal reform, ADR, and customary forms of justice by enacting a small claims procedure, allowing for a uniquely Ugandan rule of law, and creating a cohesive system of justice in the commercial realm. Part VI will conclude this article