Letter from K. Malamis, President of the Athenian Humanitarian Society, to Geraldine Ferraro

Letter from K. Malamis, President of the Athenian Humanitarian Society, to Geraldine Ferraro. Author discusses Turkish-Greek relations. Letter has handwritten notes.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_international/1365/thumbnail.jp

Quantization of a generally covariant gauge system with two super Hamiltonian constraints

The Becci-Rouet-Stora-Tyutin (BRST) operator quantization of a finite-dimensional gauge system featuring two quadratic super Hamiltonian and m linear supermomentum constraints is studied as a model for quantizing generally covariant gauge theories. The proposed model ``completely'' mimics the constraint algebra of General Relativity. The Dirac constraint operators are identified by realizing the BRST generator of the system as a Hermitian nilpotent operator, and a physical inner product is introduced to complete a consistent quantization procedure.Comment: 17 pages. Latex file. Minor changes, two references adde

The role of initial entanglement and nonGaussianity in the decoherence of photon number entangled states evolving in a noisy channel

We address the degradation of continuous variable (CV) entanglement in a noisy channel focusing on the set of photon-number entangled states. We exploit several separability criteria and compare the resulting separation times with the value of non-Gaussianity at any time, thus showing that in the low-temperature regime: i) non-Gaussianity is a bound for the relative entropy of entanglement and ii) Simon' criterion provides a reliable estimate of the separation time also for nonGaussian states. We provide several evidences supporting the conjecture that Gaussian entanglement is the most robust against noise, i.e. it survives longer than nonGaussian one, and that this may be a general feature for CV systems in Markovian channels.Comment: revised version, title and figures change

Modeling the chemical evolution of Omega Centauri using three-dimensional hydrodynamical simulations

We present a hydrodynamical and chemical model for the globular cluster Omega Cen, under the assumption that it is the remnant of an ancient dwarf spheroidal galaxy (dSph), the bulk of which was disrupted and accreted by our Galaxy ~10 Gyr ago. We highlight the very different roles played by Type II and Type Ia supernovae (SNe) in the chemical enrichment of the inner regions of the putative parent dSph. While the SNe II pollute the interstellar medium rather uniformly, the SNe Ia ejecta may remain confined inside dense pockets of gas as long as succesive SNe II explosions spread them out. Stars forming in such pockets have lower alpha-to-iron ratios than the stars forming elsewhere. Owing to the inhomogeneous pollution by SNe Ia, the metal distribution of the stars in the central region differs substantially from that of the main population of the dwarf galaxy, and resembles that observed in Omega Cen. This inhomogeneous mixing is also responsible for a radial segregation of iron-rich stars with depleted [alpha/Fe] ratios, as observed in some dSphs. Assuming a star formation history of ~1.5 Gyr, our model succeeds in reproducing both the iron and calcium distributions observed in Omega Cen and the main features observed in the empirical alpha/Fe versus Fe/H plane. Finally, our model reproduces the overall spread of the color-magnitude diagram, but fails in reproducing the morphology of the SGB-a and the double morphology of the main sequence. However, the inhomogeneous pollution reduces (but does not eliminate) the need for a significantly enhanced helium abundance to explain the anomalous position of the blue main sequence. Further models taking into account the dynamical interaction of the parent dwarf galaxy with the Milky Way and the effect of AGB pollution will be required.Comment: 15 pages, 13 figures. MNRAS accepte

Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations

A self-regulating magnetic flux pumping mechanism in tokamaks that maintains the core safety factor at $q\approx 1$, thus preventing sawteeth, is analyzed in nonlinear 3D magnetohydrodynamic simulations using the M3D-C$^1$ code. In these simulations, the most important mechanism responsible for the flux pumping is that a saturated $(m=1,n=1)$ quasi-interchange instability generates an effective negative loop voltage in the plasma center via a dynamo effect. It is shown that sawtoothing is prevented in the simulations if $\beta$ is sufficiently high to provide the necessary drive for the $(m=1,n=1)$ instability that generates the dynamo loop voltage. The necessary amount of dynamo loop voltage is determined by the tendency of the current density profile to centrally peak which, in our simulations, is controlled by the peakedness of the applied heat source profile.Comment: submitted to Physics of Plasmas (23 pages, 15 Figures

Quantization of generally covariant systems with extrinsic time

A generally covariant system can be deparametrized by means of an ``extrinsic'' time, provided that the metric has a conformal ``temporal'' Killing vector and the potential exhibits a suitable behavior with respect to it. The quantization of the system is performed by giving the well ordered constraint operators which satisfy the algebra. The searching of these operators is enlightned by the methods of the BRST formalism.Comment: 10 pages. Definite published versio

Letter from Jamus J. K. Smith, Director of Law and Administration for the City of Aberdeen, to Geraldine Ferraro

Letter from Jamus J. K. Smith, Director of Law and Administration for the City of Aberdeen, to Geraldine Ferraro. Mr. Smith discusses nuclear policy.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_international/1346/thumbnail.jp

Prescribing HIV PrEP and Education Needs Among Care Providers

Preexposure prophylaxis (PrEP) is a biomedical intervention to prevent the spread of HIV. Underprescribing PrEP could increase the probability of HIV exposure among serodivergent couples/partners and people who do not practice safer sex. Previous research on PrEP did not assess the association between awareness of PrEP, years of experience of the providers, provider types, and the frequency of PrEP among physicians. The purpose of this study is to test the hypothesis that awareness of PrEP, years of experience, and provider types might be predictors of the frequency of PrEP among physicians. Precaution adoption process model and cross-sectional design were applied to survey 100 physicians. Kendall\u27s b correlation test and Fisher’s exact test showed that awareness was the primary barrier to prescribing PrEP at the providers’ level. Higher awareness of PrEP and years of experience were associated with the frequency of PrEP prescription. However, there was an insignificant difference between provider types and the frequency of PrEP prescription. The findings support the notion that independent from their years of experience and specialty, the more physicians know about PrEP, the more they prescribe it. The results and recommendations contribute to positive social change by providing information to develop a comprehensive PrEP education curriculum for care providers. Our findings indicate that physicians need education and training to fully understand the potential for PrEP to reduce HIV transmission

Dynamical age differences among coeval star clusters as revealed by blue stragglers

Globular star clusters that formed at the same cosmic time may have evolved rather differently from a dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend progressively to segregate stars more massive than the average towards the cluster centre. Therefore clusters with the same chronological age may have reached quite different stages of their dynamical history (that is, they may have different dynamical ages). Blue straggler stars have masses greater than those at the turn-off point on the main sequence and therefore must be the result of either a collision or a mass-transfer event. Because they are among the most massive and luminous objects in old clusters, they can be used as test particles with which to probe dynamical evolution. Here we report that globular clusters can be grouped into a few distinct families on the basis of the radial distribution of blue stragglers. This grouping corresponds well to an effective ranking of the dynamical stage reached by stellar systems, thereby permitting a direct measure of the cluster dynamical age purely from observed properties.Comment: Published on the 20 December 2012 issue of Natur