The hidden value of air transportation infrastructure

Air transportation is a key strategic asset in that it provides access to markets and thereby enables the economic development of nations. Thus, in order to maintain their competitiveness in a global economy, countries must invest in air transportation infrastructure to ensure their ability to meet current and future demand for aviation services. The objective of this paper is to develop and illustrate a methodology for evaluating the strategic value of air transportation infrastructure, in particular the benefits associated with the ability to react quickly to changes in the market. The hypothesis is that by recognizing and taking advantage of this strategic value, it may be possible to design better policies for aviation infrastructure delivery

General Relativistic Simulations of Magnetized Plasmas around Merging Supermassive Black Holes

Coalescing supermassive black hole binaries are produced by the mergers of galaxies and are the most powerful sources of gravitational waves accessible to space-based gravitational observatories. Some such mergers may occur in the presence of matter and magnetic fields and hence generate an electromagnetic counterpart. In this Letter, we present the first general relativistic simulations of magnetized plasma around merging supermassive black holes using the general relativistic magnetohydrodynamic code Whisky. By considering different magnetic field strengths, going from non-magnetically dominated to magnetically dominated regimes, we explore how magnetic fields affect the dynamics of the plasma and the possible emission of electromagnetic signals. In particular we observe a total amplification of the magnetic field of ~2 orders of magnitude which is driven by the accretion onto the binary and that leads to much stronger electromagnetic signals, more than a factor of 10^4 larger than comparable calculations done in the force-free regime where such amplifications are not possible.Comment: 7 pages, 5 figures. Minor changes to match version accepted for publication on The Astrophysical Journal Letter

Investments Under Uncertainty in Air Transportation: A Real Options Perspective

Infrastructure investment decisions in air transportation are difficult because of long lead times, large capital expenditures and the technological, market and political uncertainties inherent in aviation. In such an environment, a flexible investment strategy is a means of managing risk. The central idea is to structure the investment so that it would benefi t from the upside potential if circumstances are resolved favorably, but would be protected from downside losses otherwise. In this paper, an evaluation methodology based on system dynamics and Monte Carlo simulation in a real options framework is utilized to evaluate different flexible infrastructure delivery strategies

Deep GALEX Observations of the Coma Cluster: Source Catalog and Galaxy Counts

We present a source catalog from deep 26 ks GALEX observations of the Coma cluster in the far-UV (FUV; 1530 A) and near-UV (NUV; 2310 A) wavebands. The observed field is centered 0.9 deg (1.6 Mpc) south-west of the Coma core, and has full optical photometric coverage with SDSS. The catalog consists of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically-confirmed Coma member galaxies that range from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is ~80% complete to NUV=23 and FUV=23.5, and has a limiting depth at NUV=24.5 and FUV=25.0 which corresponds to a star formation rate of ~0.001 Msun/yr at the distance of Coma. Our deep GALEX observations required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as a position prior), and relied on the GALEX pipeline catalog for bright/extended objects. We performed simulations to assess the influence that systematic effects (e.g. object blends, source confusion, Eddington Bias) have on source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is also free from source confusion over the UV magnitude range studied here; conversely, we estimate that the GALEX pipeline catalogs are confusion limited at magnitudes fainter than NUV~23 and FUV~24. We have measured the total UV galaxy counts using our catalog and report a ~50% excess of counts across FUV=22-23.5 and NUV=21.5-23 relative to previous GALEX measurements, which is not attributed to cluster member galaxies. Our galaxy counts are a better match to deeper UV counts measured with HST.Comment: 27 pages, 13 figures, 4 tables, accepted for publication in ApJ

IO vs OI in Higher-Order Recursion Schemes

We propose a study of the modes of derivation of higher-order recursion schemes, proving that value trees obtained from schemes using innermost-outermost derivations (IO) are the same as those obtained using unrestricted derivations. Given that higher-order recursion schemes can be used as a model of functional programs, innermost-outermost derivations policy represents a theoretical view point of call by value evaluation strategy.Comment: In Proceedings FICS 2012, arXiv:1202.317

Capitalist discourse, subjectivity and Lacanian psychoanalysis

This paper studies how subjectivity in capitalist culture can be characterized. Building on Lacan’s later seminars XVI, XVII, XVIII, and XIX, the author first outlines Lacan’s general discourse theory, which includes four characteristic discourses: the discourse of the master, the discourse of the university, the discourse of the hysteric and the discourse of the analyst. Next, the author explores the subjectivity and the mode of dealing with jouissance and semblance, which is entailed in a fifth type of discourse, the capitalist discourse, discussed by Lacan (1972). Indeed, like the other discourses that Lacan discerns, the discourse of the capitalist can be thought of as a mode of dealing with the sexual non-rapport. It is argued that in the case of neurosis the discourse of the capitalist functions as an attempt to ignore the sexual non-rapport and the dimension of the unconscious. Psychosis, by contrast, is marked by an a priori exclusion from discourse. In that case, consumerist ways of relating to the other might offer a semblance, and thus the possibility of inventing a mode of relating to the other. Two clinical vignettes are presented to illustrate this perspective: one concerning the neurotic structure and one concerning the psychotic structure

Estimation of the Economic Benefit of Air Jamaica to Jamaica between 1995 and 2004

In this study, we estimate the economic benefit of Air Jamaica to Jamaica between 1995 and 2004. Specifically, we determine the economic benefit of Air Jamaica by estimating the economic contribution of air transportation for the case where Air Jamaica does not exist and then subtracting this value from the economic contribution of air transportation for the case where Air Jamaica does exist. Thus the value we determine is the incremental contribution of Air Jamaica to the Jamaican economy, i.e. the benefit that can only be attributed to the presence of Air Jamaica. Although there are many different ways in which airlines contribute to socioeconomic growth, only two of these mechanisms are explored in this study: 1) the portion of airline revenues that remain in Jamaica by virtue of the wages that are paid to residents of Jamaica, and the goods and services that are purchased from companies in Jamaica; 2) the expenditures of foreign visitors. Therefore, this study represents a conservative estimate of the benefit of Air Jamaica to the Jamaican economy. The results of our analysis indicate that the economic benefit of Air Jamaica to Jamaica between 1995 and 2004 economy was US5.491 Billion of which US$1.830 Billion was a direct incremental contribution to the economy and US$3.661 Billion is the corresponding indirect incremental contribution

Attentional Switching in Humans and Flies: Rivalry in Large and Miniature Brains

Human perception, and consequently behavior, is driven by attention dynamics. In the special case of rivalry, where attention alternates between competing percepts, such dynamics can be measured and their determinants investigated. A recent study in the fruit fly, Drosophila melanogaster, now shows that the origins of attentional rivalry may be quite ancient. Furthermore, individual variation exists in the rate of attentional rivalry in both humans and flies, and in humans this is under substantial genetic influence. In the pathophysiological realm, slowing of rivalry rate is associated with the heritable psychiatric condition, bipolar disorder. Fly rivalry may therefore prove a powerful model to examine genetic and molecular influences on rivalry rate, and may even shed light on human cognitive and behavioral dysfunction

Baseline coral disease surveys within three marine parks in Sabah, Borneo

Two of the most significant threats to coral reefs worldwide are bleaching and disease. However, there has been a scarcity of research on coral disease in South-East Asia, despite the high biodiversity and the strong dependence of local communities on the reefs in the region. This study provides baseline data on coral disease frequencies within three national parks in Sabah, Borneo, which exhibit different levels of human impacts and management histories. High mean coral cover (55%) and variable disease frequency (mean 0.25 diseased colonies m−2) were found across the three sites. Highest disease frequency (0.44 diseased colonies per m 2) was seen at the site closest to coastal population centres. Bleaching and pigmentation responses were actually higher at Sipadan, the more remote, offshore site, whereas none of the other coral diseases detected in the other two parks were detected in Sipadan. Results of this study offer a baseline dataset of disease in these parks and indicate the need for continued monitoring, and suggest that coral colonies in parks under higher anthropogenic stressors and with lower coral cover may be more susceptible to contracting disease