A Flaring Megamaser in Mrk 348

We report new observations of the H2O megamaser in the Seyfert 2 galaxy Mrk 348. Following our initial detection in 2000 March using the Effelsberg 100 m telescope, re-analysis of previous data on this source indicates that the maser was present but only marginally detectable in late 1997. Monitoring through late 2000 shows that the maser has again decreased to its original level. The H2O line is redshifted by ~130 km/s with respect to the systemic velocity, is extremely broad, with a FWHM of 130 km/s, and has no detectable high velocity components within 1500 km/s on either side of the strong line. Followup VLBA observations show that the maser emission emanates entirely from a region >0.25 pc in extent, toward the base of the radio jet.Comment: 4 pages, 2 figures, to appear in Cosmic Masers: from Protostars to Black Holes, IAU 206, Eds. V. Migenes et al., ASP Conference Serie

Thinking beyond the hybrid:“actually-existing” cities “after neoliberalism” in Boyle <i>et al.</i>

In their article, ‘The spatialities of actually existing neoliberalism in Glasgow, 1977 to present’, Mark Boyle, Christopher McWilliams and Gareth Rice (2008) usefully problematise our current understanding of neoliberal urbanism. Our response is aimed at developing a sympathetic but critical approach to Boyle et al's understanding of neoliberal urbanism as illustrated by the Glasgow example. In particular, the counterposing by Boyle et al of a 'hybrid, mutant' model to a 'pure' model of neoliberalism for us misrepresents existing models of neoliberalism as a perfectly finished object rather than a roughly mottled process. That they do not identify any ‘pure’ model leads them to create a straw construct against which they can claim a more sophisticated, refined approach to the messiness of neoliberal urbanism. In contrast, we view neoliberalism as a contested and unstable response to accumulation crises at various scales of analysis

Refractive Index of Humid Air in the Infrared: Model Fits

The theory of summation of electromagnetic line transitions is used to tabulate the Taylor expansion of the refractive index of humid air over the basic independent parameters (temperature, pressure, humidity, wavelength) in five separate infrared regions from the H to the Q band at a fixed percentage of Carbon Dioxide. These are least-squares fits to raw, highly resolved spectra for a set of temperatures from 10 to 25 C, a set of pressures from 500 to 1023 hPa, and a set of relative humidities from 5 to 60%. These choices reflect the prospective application to characterize ambient air at mountain altitudes of astronomical telescopes.Comment: Corrected exponents of c0ref, c1ref and c1p in Table

On the Prospects for Laser Cooling of TlF

We measure the upper state lifetime and two ratios of vibrational branching fractions f_{v'v} on the B^{3}\Pi_{1}(v') - X^{1}\Sigma^{+}(v) transition of TlF. We find the B state lifetime to be 99(9) ns. We also determine that the off-diagonal vibrational decays are highly suppressed: f_{01}/f_{00} < 2x10^{-4} and f_{02}/f_{00} = 1.10(6)%, in excellent agreement with their predicted values of f_{01}/f_{00} < 8x10^{-4} and f_{02}/f_{00} = 1.0(2)% based on Franck-Condon factors calculated using Morse and RKR potentials. The implications of these results for the possible laser cooling of TlF and fundamental symmetries experiments are discussed.Comment: 5 pages, 2 figure

Modeled larval fish prey fields and growth rates help predict recruitment success of cod and anchovy in the North Sea

Abstract. We introduce a new, coupled modeling approach for simulating ecosystem-wide patterns in larval fish foraging and growth. An application of the method reveals how interplay between temperature and plankton dynamics during 1970-2009 impacted a cold-water species (Atlantic cod Gadus morhua) and a warm-water species (European anchovy Engraulis encrasicolus) in the North Sea. Larval fish growth rates were estimated by coupling models depicting traitbased foraging and bioenergetics of individuals, spatiotemporal changes in their prey field, and the biogeochemistry and hydrodynamics of the region. The biomass composition of modeled prey fields varied from 89% nano-, 10% micro-, and 1% mesoplankton to 15% nano-, 20% micro-, and 65% mesoplankton. The mean slope of the normalized biomass size spectrum was near -1.2, consistent with theoretical and empirical estimates. Median larval fish growth rates peaked in June for cod (24% d(-1)) and in July for anchovy (17% d(-1)). Insufficient prey resources played a substantial role in limiting the growth rates of cod larvae. Anchovy were consistently limited by cold temperatures. Faster median larval growth during specific months was significantly (p < 0.05) positively associated with detrended (i.e. higher than expected) juvenile recruitment indices in cod (rank correlation Kendall's tau = 22%) and anchovy (tau = 42%). For cod, the most predictive month was February, which was also when food limitation was most prevalent. The continued development of modeling tools based on first principles can help further a mechanistic understanding of how changes in the environment affect the productivity of living marine resources

X-ray emission from massive stars in Cyg OB2

We report on the analysis of the Chandra-ACIS data of O, B and WR stars in the young association Cyg OB2. X-ray spectra of 49 O-stars, 54 B-stars and 3 WR-stars are analyzed and for the brighter sources, the epoch dependence of the X-ray fluxes is investigated. The O-stars in Cyg\,OB2 follow a well-defined scaling relation between their X-ray and bolometric luminosities: log(Lx/Lbol) = -7.2 +/- 0.2. This relation is in excellent agreement with the one previously derived for the Carina OB1 association. Except for the brightest O-star binaries, there is no general X-ray overluminosity due to colliding winds in O-star binaries. Roughly half of the known B-stars in the surveyed field are detected, but they fail to display a clear relationship between Lx and Lbol. Out of the three WR stars in Cyg OB2, probably only WR144 is itself responsible for the observed level of X-ray emission, at a very low log(Lx/Lbol) = -8.8 +/- 0.2. The X-ray emission of the other two WR-stars (WR145 and 146) is most probably due to their O-type companion along with a moderate contribution from a wind-wind interaction zone.Comment: Accepted for an ApJS Special Issue devoted to the Chandra Cygnus OB2 Legacy Surve

An extended supersonic combustion model for the dynamic analysis of hypersonic vehicles

The development of an advanced dynamic model for aeroelastic hypersonic vehicles powered by air breathing engines requires an adequate engine model. This report provides a discussion of some of the more important features of supersonic combustion and their relevance to the analysis and design of supersonic ramjet engines. Of particular interest are those aspects of combustion that impact the control of the process. Furthermore, the report summarizes efforts to enhance the aeropropulsive/aeroelastic dynamic model developed at the Aerospace Research Center of Arizona State University by focusing on combustion and improved modeling of this flow. The expanded supersonic combustor model described here has the capability to model the effects of friction, area change, and mass addition, in addition to the heat addition process. A comparison is made of the results from four cases: (1) heat addition only; (2) heat addition plus friction; (3) heat addition, friction, and area reduction, and (4) heat addition, friction, area reduction, and mass addition. The relative impact of these effects on the Mach number, static temperature, and static pressure distributions within the combustor are then shown. Finally, the effects of frozen versus equilibrium flow conditions within the exhaust plume is discussed

Measurement of the electron electric dipole moment using GdIG

A new method for the detection of the electron edm using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the samples magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron edm of 5E-24 e-cm, which is a factor of 40 below the limit obtained from the only previous solid-state edm experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.Comment: 10 pages, 5 figures, v2:references corrected, submitted to PRL, v3:added labels to figure

Biomechanical analysis of bone remodeling following mandibular reconstruction using fibula free flap

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Whilst the newly established biomechanical conditions following mandibular reconstruction using fibula free flap can be a critical determinant for achieving favorable bone union, little has been known about their association in a time-dependent fashion. This study evaluated the bone healing/remodeling activity in reconstructed mandible and its influence on jaw biomechanics using CT data, and further quantified their correlation with mechanobiological responses through an in-silico approach. A 66-year-old male pa- tient received mandibular reconstruction was studied. Post-operative CT scans were taken at 0, 4, 16 and 28 months. Longitudinal change of bone morphologies and mineral densities were measured at three bone union interfaces (two between the fibula and mandibular bones and one between the osteotomized fibulas) to investigate bone healing/remodeling events. Three-dimensional finite element models were created to quantify mechanobiological responses in the bone at these different time points. Bone mineral density increased rapidly along the bone interfaces over the first four months. Cortical bridging formed at the osteotomized interface earlier than the other two interfaces with larger shape discrepancy between fibula and mandibular bones. Bone morphology significantly affected mechanobiological responses in the osteotomized region ( R 2 > 0.77). The anatomic position and shape discrepancy at bone union affected the bone healing/remodeling process.This work was supported by the Australian Research Council (ARC) through the Discovery and Fellowship schemes ( DP160104602 and FT120100947 )

Disentangling the Circumnuclear Environs of Centaurus A: III. An Inner Molecular Ring, Nuclear Shocks and the CO to warm H2 interface

We present the distribution and kinematics of the molecular gas in the circumnuclear disk (CND, 400 pc x 200 pc) of Centaurus A with resolutions of ~5 pc (0.3 arcsec) and shed light onto the mechanism feeding the Active Galactic Nucleus (AGN) using CO(3-2), HCO+(4-3), HCN(4-3), and CO(6-5) observations obtained with ALMA. Multiple filaments or streamers of tens to a hundred parsec scale exist within the CND, which form a ring-like structure with an unprojected diameter of 9 x 6 arcsec (162pc x 108pc) and a position angle PA = 155deg. Inside the nuclear ring, there are two leading and straight filamentary structures with lengths of about 30-60pc at PA = 120deg on opposite sides of the AGN, with a rotational symmetry of 180deg and steeper position-velocity diagrams, which are interpreted as nuclear shocks due to non-circular motions. Along the filaments, and unlike other nearby AGNs, several dense molecular clumps present low HCN/HCO+(4-3) ratios (~0.5). The filaments abruptly end in the probed transitions at r = 20pc from the AGN, but previous near-IR H2 (J=1-0) S(1) maps show that they continue in an even ~1000 K), winding up in the form of nuclear spirals, and forming an inner ring structure with another set of symmetric filaments along the N-S direction and within r = 10pc. The molecular gas is governed primarily by non-circular motions, being the successive shock fronts at different scales where loss of angular momentum occurs, a mechanism which may feed efficiently powerful radio galaxies down to parsec scales.Comment: 46 pages. Accepted for publication in Ap