An X-ray Survey of Galaxies in Pairs

Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of fifty-two pairs of galaxies from the Catalog of Paired Galaxies Karachentsev (1972) whose coordinates overlap ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log l_x for early-type pairs is 41.35 +/-0.21 while the mean log l_x predicted using the l_x-l_b relationship for isolated early-type galaxies is 42.10 +/-0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared to isolated galaxies, for the same l_b. A significant fraction of the mixed pair sample also appear similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of ~10 - 50 kpc, much smaller than group intergalactic medium and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x10^42 ergs/sec, is an exception. The extent of it's X-ray emission, >169 kpc, and HWHM, ~80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, ~81% confidence, between l_x and l_b, presumably due to variations in gas content within the galaxies. No correlation between l_x and the pair velocity difference, separation, or far-infrared luminosity is found though the detection rate is low, 22%.Comment: 40 pages, 6 jpg figures, ApJ (in press

Recent Decisions

Comments on recent decisions by Richard D. Schiller, J. M. Lynes, Harry Contos, R. L. Cousineau, and Norris James Bishton

Nitrate Radical Facilitates Indirect Benzyl Alcohol Oxidation on Bismuth(III) Vanadate Photoelectrodes

Bismuth(III) vanadate (BiVO4) films show activity for direct benzyl alcohol (PhCH2OH) oxidation to benzaldehyde (PhCHO) in acetonitrile solvent. Introducing tetrabutylammonium nitrate (Bu4NNO3) drastically reduces the overpotential required to generate the PhCHO product while maintaining a high faradaic efficiency (FE) >90 %. BiVO4 corrosion accompanies PhCH2OH oxidation. However, the presence of nitrate ions (NO3−) results in significantly less bismuth‐ and vanadium‐ion leaching (determined by ICP‐MS analysis), as well as reduced surface roughening (determined by SEM imaging). In this reaction, it is proposed that rate‐determining NO3− oxidation generates a highly reactive nitrate radical (NO3⋅) that reacts with PhCH2OH by hydrogen‐atom abstraction (HAT). NO3− is stoichiometrically consumed by the irreversible formation of electrochemically inert HNO3, characterized by an ECi mechanism, rather than a catalytic EC′ mechanism. In the presence of PhCH2OH, NO3− oxidation on BiVO4 becomes more facile; every order of magnitude increase in PhCH2OH concentration shifts the NO3−/ NO3⋅ equilibrium potential negatively by 200 mV. The shift results from the introduction of a consumption pathway for the nitrate radical intermediate via a coupled chemical step with benzyl alcohol. This report is the first example of photoelectrochemical NO3⋅ generation to initiate indirect PhCH2OH oxidation.Initiate to generate: Bismuth(III) vanadate (BiVO4) films show activity for direct benzyl alcohol (PhCH2OH) oxidation to benzaldehyde (PhCHO) in acetonitrile solvent. Introducing tetrabutylammonium nitrate (Bu4NNO3) drastically reduces the overpotential required to generate the PhCHO product while maintaining a high faradaic efficiency. BiVO4 corrosion accompanies PhCH2OH oxidation. Moreover, the presence of nitrate ions (NO3−) results in significantly less bismuth‐ and vanadium‐ion leaching as well as reduced surface roughening.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/3/celc202000911.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/2/celc202000911-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/1/celc202000911_am.pd

Foreign Ownership and Strike Activity in Canada

Il existe plusieurs études sur l'activité de grève au Canada. La plupart d'entre elles tentent d'expliquer l'évolution temporelle et les disparités interindustrielles dans l'activité de grève. À venir jusqu'à tout récemment (Ng and Maki 1988), aucune n'avait pris en considération l'impact possible du contrôle étranger sur l'importance de l'activité de grève au Canada. Or, il faut se rappeler que le Canada est toujours uncas unique à cet égard parmi les pays industrialisés. En effet, dans ce pays, quelque 54 % des actifs des compagnies privées des secteurs primaire et secondaire sont propriétés étrangères. Il est alors tout à fait pertinent de se demander si cette caractéristique particulière de l'économie n'expliquerait pas partiellement une autre de ses caractéristiques, à savoir une activité de grève très élevée selon les standards internationaux. Ng et Maki (1988) ont étudié empiriquement la relation possible entre le contrôle étranger et l'activité de grève au Canada pour en conclure que les filiales canadiennes de compagnies ne semblaient pas avoir des taux de grève plus élevés que les compagnies canadiennes. Toutefois, les auteurs soulignent qu'il faudrait une étude faite à l'aide de microdonnées pour pouvoir répondre avec davantage de précision à la question de savoir si le contrôle étranger affecte l'activité de grève.Nous avions à notre disposition de telles microdonnées pour la période 1969-1982 et c'est pourquoi nous avons décidé de réexaminer l'incidence possible du contrôle étranger sur l'activité de grève au Canada. Pour ce faire, nous avons utilisé un modèle empirique de grève déjà éprouvé et diffusé dans la communauté scientifique (Cousineau et Lacroix 1986) et qui repose sur l'approche théorique et Siebert et Addison (1981) qui veut que les grèves soient des accidents se produisant dans le cours des négociations. Ces accidents sont évidemment plus probables lorsque la qualité de l'information disponible aux parties se détériore. C'est le cas, par exemple, dans des périodes de perturbations économiques majeures où la valeur prospective d'indicateurs tels l'inflation, le chômage, la production, devient très faible. Dès lors, des interprétations divergentes des mêmes indicateurs peuvent entraîner des erreurs d'évaluation des rapports de force en présence, cause première des grèves.Nous avons analysé, à l'aide de cette approche, la question du contrôle étranger et son incidence possible sur l'activité de grève. Nous avons alors réalisé qu'un grand nombre de facteurs ayant des effets opposés jouaient sur la relation possible entre le contrôle étranger et l'activité de grève. Tant et si bien qu'aucune attente précise ne pouvait logiquement être inférée quant au sens de la relation. La question devenait donc une question empirique.Nous avons intégré alternativement deux variables d'approximation du contrôle étranger dans une équation générale de grève, prenant en compte un ensemble d'autres facteurs pouvant expliquer l'activité de grève. La première variable (FOREG 1), prenait la valeur 1 si 50 °/o ou plus des droits de vote de la compagnie où la convention collective avait été signée étaient détenus à l'étranger et la valeur 0 s'il en était autrement. L'autre variable (FOREG 2), était plus restrictive puisqu'elle prenait la valeur 1 si 90 % et plus des droits de vote étaient détenus à l'étranger. Les résultats que nous avons obtenus pour ces deux variables sont les suivants. La variable FOREG 1 a un coefficient estimé négatif et statistiquement significatif au niveau de 0,10. Ce résultat nous dit que, toutes autres choses étant égales par ailleurs, la détention étrangère diminue la probabilité de grève de cinq points de pourcentage. En utilisant FOREG 2, nous avons trouvé une augmentation de la valeur du coefficient estimé qui devient significatif au niveau de 0,05. En fait, dans ce cas, la détention étrangère diminue la probabilité de grève de quelque sept points de pourcentage. En somme, tous les résultats que nous avons obtenus pointent dans la même direction. Au Canada, il semble que le contrôle étranger a un effet négatif sur l'activité de grève. Ces résultats vont à l'encontre d'une opinion généralement acceptée mais sont tout à fait compatibles avec les conclusions que l'on peut tirer d'un modèle informationnel de grève.This microeconomic study of strike activity adds to an already tested empirical strike model, variables that are related to foreign-owned firms in Canada. AU results converge to the same and unique conclusion: foreign-owned firms in Canada show a lower strike propensity, everything else being constant. Such a result suggests that multinational firms may well develop bargaining "protocoles" that overcompensate problems of credibility and information expected to be associated with foreign-owned property

Modelling the impacts of ammonia emissions reductions on North American air quality

A unified regional air-quality modelling system (AURAMS) was used to investigate the effects of reductions in ammonia emissions on regional air quality, with a focus on particulate-matter formation. Three simulations of one-year duration were performed for a North American domain: (1) a base-case simulation using 2002 Canadian and US national emissions inventories augmented by a more detailed Canadian emissions inventory for agricultural ammonia; (2) a 30% North-American-wide reduction in agricultural ammonia emissions; and (3) a 50% reduction in Canadian beef-cattle ammonia emissions. The simulations show that a 30% continent-wide reduction in agricultural ammonia emissions lead to reductions in median hourly PM<sub>2.5</sub> mass of <1 μg m<sup>−3</sup> on an annual basis. The atmospheric response to these emission reductions displays marked seasonal variations, and on even shorter time scales, the impacts of the emissions reductions are highly episodic: 95th-percentile hourly PM<sub>2.5</sub> mass decreases can be up to a factor of six larger than the median values. <br><br> A key finding of the modelling work is the linkage between gas and aqueous chemistry and transport; reductions in ammonia emissions affect gaseous ammonia concentrations close to the emissions site, but substantial impacts on particulate matter and atmospheric deposition often occur at considerable distances downwind, with particle nitrate being the main vector of ammonia/um transport. Ammonia emissions reductions therefore have trans-boundary consequences downwind. Calculations of critical-load exceedances for sensitive ecosystems in Canada suggest that ammonia emission reductions will have a minimal impact on current ecosystem acidification within Canada, but may have a substantial impact on future ecosystem acidification. The 50% Canadian beef-cattle ammonia emissions reduction scenario was used to examine model sensitivity to uncertainties in the new Canadian agricultural ammonia emissions inventory, and the simulation results suggest that further work is needed to improve the emissions inventory for this particular sector. It should be noted that the model in its current form neglects coarse mode base cation chemistry, so the predicted effects of ammonia emissions reductions shown here should be considered upper limits

Proving Determinacy of the PharOS Real-Time Operating System

International audienceExecutions in the PharOS real-time system are deterministic in the sense that the sequence of local states for every process is independent of the order in which processes are scheduled. The essential ingredient for achieving this property is that a temporal window of execution is associated with every instruction. Messages become visible to receiving processes only after the time window of the sending message has elapsed. We present a high-level model of PharOS in TLA+ and formally state and prove determinacy using the TLA+ Proof System

Evaluation of a digital diabetes prevention program adapted for the Medicaid population: Study design and methods for a non-randomized, controlled trial.

Previous studies have shown that lifestyle modification can successfully prevent or delay development of type 2 diabetes. This trial aimed to test if an underserved, low-income population would engage in a digital diabetes prevention program and successfully achieve lifestyle changes to reduce their risk of type 2 diabetes. Participants were recruited from three health care facilities serving low-income populations. The inclusion criteria were: a recent blood test indicating prediabetes, body mass index (BMI) \u3e 24 kg/

Voluntary DNA-based information exchange and contact services following donor conception: an analysis of service users’ needs

Medical science has enabled the creation of families through the use of donor conception but some lifelong policy and practice implications are only recently being recognized. Research and practice have shown that donor conception can, for some, carry substantial long-term consequences. In this paper we present findings from a questionnaire-based study that sought to shed light on donor-conceived adults’ and gamete donors’ views on service and support needs when searching for genetic relatives with the aid of DNA testing. The findings demonstrate the complexity and sensitivity of providing services in this newly emerging area of need. Such provision requires collaboration between very different disciplines and agencies (scientific and psychosocial), introduces the potential for blurring of lines of accountability and responsibility, and highlights the challenges of identifying appropriate funding streams. In addition, the findings demonstrate the opportunities and limitations afforded by the use of DNA in identifying unknown genetic relatives

Realizing Dynamic and Efficient Bipedal Locomotion on the Humanoid Robot DURUS

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.DOI: 10.1109/ICRA.2016.7487325This paper presents the methodology used to achieve efficient and dynamic walking behaviors on the prototype humanoid robotics platform, DURUS. As a means of providing a hardware platform capable of these behaviors, the design of DURUS combines highly efficient electromechanical components with “control in the loop” design of the leg morphology. Utilizing the final design of DURUS, a formal framework for the generation of dynamic walking gaits which maximizes efficiency by exploiting the full body dynamics of the robot, including the interplay between the passive and active elements, is developed. The gaits generated through this methodology form the basis of the control implementation experimentally realized on DURUS; in particular, the trajectories generated through the formal framework yield a feedforward control input which is modulated by feedback in the form of regulators that compensate for discrepancies between the model and physical system. The end result of the unified approach to control-informed mechanical design, formal gait design and regulator-based feedback control implementation is efficient and dynamic locomotion on the humanoid robot DURUS. In particular, DURUS was able to demonstrate dynamic locomotion at the DRC Finals Endurance Test, walking for just under five hours in a single day, traveling 3.9 km with a mean cost of transport of 1.61-the lowest reported cost of transport achieved on a bipedal humanoid robot

Analytic fluid theory of beam spiraling in high-intensity cyclotrons

Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in isochronous cyclotrons in the nonrelativistic limit. With a multiscale analysis separating the time scale associated with the betatron motion and the slower time scale associated with space-charge effects, we show that the longitudinal-radial vortex motion can be understood in the frame moving with the charged beam as the nonlinear advection of the beam by the E×B velocity field, where E is the electric field due to the space charge and B is the external magnetic field. This interpretation provides simple explanations for the stability of round beams and for the development of spiral halos in elongated beams. By numerically solving the nonlinear advection equation for the beam density, we find that it is also in quantitative agreement with results obtained in particle-in-cell simulations