A type system for Continuation Calculus

Continuation Calculus (CC), introduced by Geron and Geuvers, is a simple foundational model for functional computation. It is closely related to lambda calculus and term rewriting, but it has no variable binding and no pattern matching. It is Turing complete and evaluation is deterministic. Notions like "call-by-value" and "call-by-name" computation are available by choosing appropriate function definitions: e.g. there is a call-by-value and a call-by-name addition function. In the present paper we extend CC with types, to be able to define data types in a canonical way, and functions over these data types, defined by iteration. Data type definitions follow the so-called "Scott encoding" of data, as opposed to the more familiar "Church encoding". The iteration scheme comes in two flavors: a call-by-value and a call-by-name iteration scheme. The call-by-value variant is a double negation variant of call-by-name iteration. The double negation translation allows to move between call-by-name and call-by-value.Comment: In Proceedings CL&C 2014, arXiv:1409.259

Vacuum solutions with nontrivial boundaries for the Einstein-Gauss-Bonnet theory

The classification of certain class of static solutions for the Einstein-Gauss-Bonnet theory in vacuum is presented. The spacelike section of the class of metrics under consideration is a warped product of the real line with a nontrivial base manifold. For arbitrary values of the Gauss-Bonnet coupling, the base manifold must be Einstein with an additional scalar restriction. The geometry of the boundary can be relaxed only when the Gauss-Bonnet coupling is related with the cosmological and Newton constants, so that the theory admits a unique maximally symmetric solution. This additional freedom in the boundary metric allows the existence of three main branches of geometries in the bulk, containing new black holes and wormholes in vacuum.Comment: Prepared for the proceedings of the 7th Alexander Friedmann International Seminar on Gravitation and Cosmology, July 2008, Joao Pessoa, Brasil. 4 pages, References adde

Trespass to the person, human rights and ethically contaminated food: freedom of belief and bodily autonomy

This article explores the specific question of protection which tort law in England and Wales affords to individuals who are victims of ethical spiking (consumption of food contaminated by malicious third parties which is physically harmless, but repugnant to their religion or beliefs), and moves on to analyse the wider implications for the possible evolution of trespass to the person, and the relationship between tort and human rights law in the UK. Although not a comparative piece, it draws on some features of the Spanish paradigm which illustrate significant benefits of developing the law in the English context in the manner suggested

AGN Black Hole Masses and Bolometric Luminosities

Black hole mass, along with mass accretion rate, is a fundamental property of active galactic nuclei. Black hole mass sets an approximate upper limit to AGN energetics via the Eddington limit. We collect and compare all AGN black hole mass estimates from the literature; these 177 masses are mostly based on the virial assumption for the broad emission lines, with the broad-line region size determined from either reverberation mapping or optical luminosity. We introduce 200 additional black hole mass estimates based on properties of the host galaxy bulges, using either the observed stellar velocity dispersion or using the fundamental plane relation to infer $\sigma$; these methods assume that AGN hosts are normal galaxies. We compare 36 cases for which black hole mass has been generated by different methods and find, for individual objects, a scatter as high as a couple of orders of magnitude. The less direct the method, the larger the discrepancy with other estimates, probably due to the large scatter in the underlying correlations assumed. Using published fluxes, we calculate bolometric luminosities for 234 AGNs and investigate the relation between black hole mass and luminosity. In contrast to other studies, we find no significant correlation of black hole mass with luminosity, other than those induced by circular reasoning in the estimation of black hole mass. The Eddington limit defines an approximate upper envelope to the distribution of luminosities, but the lower envelope depends entirely on the sample of AGN included. For any given black hole mass, there is a range in Eddington ratio of up to three orders of magnitude.Comment: 43 pages with 10 figures. Accepted for publication in Ap

Molecular Weight Distributions in Ideal Polymerization Reactors. An Introductory Review

The ultimate aim of polymerization reaction engineering is the production of polymers with tailor-made properties. An introductory review into this field is presented, with emphasis on the effects on the molar mass distribution (MMD), of the sought combination of polymerization mechanism, reactor type, and reactor control. Three ideal polymerization mechanisms are analyzed: free-radical, living anionic, and step-growth. Living anionic and step-growth polymerizations are similar in that their growing chains remain reactive while inside the reactor; and for these systems the narrowest MMDs are produced in reactors with narrow residence time distributions (RDT); i.e.: batch or continuous tubularreactors. In contrast, in conventional free-radical polymerizations, the polymer molecules grow in a fraction of a second and thereafter remain inactive while inside the reactor. In this case, the RTD does not affect the MMD, and the homogeneous continuous stirred-tank reactors provide the narrowest MMDs. Representative mathematical models of polymerization reactors are useful for: a) quantifying the interrelationships between their numerous inputs and outputs; and b) developing open- and closedloop strategies for increasing reactor productivity and product quality.Fil: Meira, Gregorio Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina. Universidad Nacional del Litoral; ArgentinaFil: Oliva, H.. Universidad del Zulia; Venezuel

Effective one-body dynamics in multiple-quantum NMR experiments

A suitable NMR experiment in a one-dimensional dipolar coupled spin system allows one to reduce the natural many-body dynamics into effective one-body dynamics. We verify this in a polycrystalline sample of hydroxyapatite (HAp) by monitoring the excitation of NMR many-body superposition states: the multiple-quantum coherences. The observed effective one-dimensionality of HAp relies on the quasi 1d structure of the dipolar coupled network that, as we show here, is dynamically enhanced by the quantum Zeno effect. Decoherence is also probed through a Loschmidt echo experiment, where the time reversal is implemented on the double-quantum Hamiltonian, I_{i,+}I_{j,+} + I_{i,-}I_{j,-}. We contrast the decoherence of adamantane, a standard 3d system, with that of HAp. While the first shows an abrupt Fermi-type decay, HAp presents a smooth exponential law.Comment: 8 pages, 6 figure

Near Infrared Spectroscopy of High Redshift Active Galactic Nuclei. II. Disappearing Narrow Line Regions and the Role of Accretion

We present new near infrared spectroscopic measurements for 29 luminous high-z quasars and use the data to discuss the size and other properties of the NLRs in those sources. The high resolution spectra have been used to carefully model the Fe II blends and to provide reliable [O III], Fe II and Hb measurements. We find that about 2/3 of all high luminosity sources show strong [O III] lines while the remaining objects show no or very weak such line. While weak [O III] emitters are also found among lower luminosity AGN, we argue that the implications for very high luminosity objects are different. In particular, we suggest that the averaging of these two populations in other works gave rise to claims of a Baldwin relationship in [O III] which is not confirmed by our data. We also argue that earlier proposed relations of the type R_NLR \propto L_[O III]^{1/2}, where R_NLR is the NLR radius, are theoretically sound yet they must break down for R_NLR exceeding a few kpc. This suggests that the NLR properties in luminous sources are different from those observed in nearby AGN. In particular, we suggest that some sources lost their very large, dynamically unbound NLR while others are in a phase of violent star-forming events that produce a large quantity of high density gas in the central kpc. This gas is ionized and excited by the central radiation source and its spectroscopic properties may be different from those observed in nearby, lower luminosity NLRs. We also discuss the dependence of EW(Hb) and Fe II/Hb on L, M_BH, and accretion rate for a large sample of AGNs. The strongest dependence of the two quantities is on the accretion rate and the Fe II/Hb correlation is probably due to the EW(Hb) dependence on accretion rate. We show the most extreme values measured so far of Fe II/Hb and address its correlation with EW([O III]).Comment: 10 pages (emulateapj), 9 figures. Accepted by Ap

Infrared Spectroscopy of GX 1+4/V2116 Oph: Evidence for a Fast Red Giant Wind?

We present infrared spectroscopy of the low-mass X-ray binary GX 1+4/V2116 Oph. This symbiotic binary consists of a 2-min accretion-powered pulsar and an M5 III red giant. A strong He I 1.083 micron emission line with a pronounced P Cygni profile was observed. From the blue edge of this feature, we infer an outflow velocity of 250(50) km/s. This is an order of magnitude faster than a typical red giant wind, and we suggest that radiation from the accretion disk or the neutron star may contribute to the acceleration of the outflow. We infer a wind mass loss rate of around 10^-6 Msun/yr. Accretion from such a strong stellar wind provides a plausible alternative to Roche lobe overflow for supplying the accretion disk which powers the X-ray source. The H I Paschen beta and He I 1.083 micron lines showed no evidence for the dramatic changes previously reported in some optical lines, and no evidence for pulsations at the 2-min pulsar period.Comment: 11 pages including 2 PS figures. To appear in ApJ Letter

[Fe II] and H2 filaments in the Supernova Remnant G11.2-0.3: Supernova Ejecta and Presupernova Circumstellar Wind

We present the results of near-infrared imaging and spectroscopic observations of the young, core-collapse supernova remnant (SNR) G11.2-0.3. In the [Fe II] 1.644 um image, we first discover long, clumpy [Fe II] filaments within the radio shell of the SNR, together with some faint, knotty features in the interior of the remnant. We have detected several [Fe II] lines and HI Br-G line toward the peak position of the bright southeastern [Fe II] filament. The derived extinction is large (Av=13 mag) and it is the brightest [Fe II] filament detected toward SNRs to date. By analyzing two [Fe II] 1.644 um images obtained in 2.2 yrs apart, we detect a proper motion corresponding to an expansion rate of 0.''035 (0.''013) /yr [or 830 (310) km/s]. We also discover two small H2 filaments. One is bright and along the SE boundary of the radio shell, while the other is faint and just outside of its NE boundary. We have detected H2 (2-1) S(3) line toward the former filament and derive an excitation temperature of 2,100 K. We suggest that the H2 filaments are dense clumps in a presupernova circumstellar wind swept up by the SNR shock while the [Fe II] filaments are probably composed of both shocked wind material and shocked supernova (SN) ejecta. The distribution of [Fe II] filaments may indicate that the SN explosion in G11.2-0.3 was asymmetric as in Cassiopeia A. Our results support the suggestion that G11.2-0.3 is a remnant of a SN IIL/b interacting with a dense red supergiant wind.Comment: 30 pages with 10 figures, To appear in the Astrophysical Journa