Disc wind models for FU Ori objects

We present disc wind models aimed at reproducing the main features of the strong Na I resonance line P-Cygni profiles in the rapidly-accreting pre-main sequence FU Ori objects. We conducted Monte Carlo radiative transfer simulations for a standard magnetocentrifugally driven wind (MHD) model and our own "Genwind" models, which allows for a more flexible wind parameterisation. We find that the fiducial MHD wind and similar Genwind models, which have flows emerging outward from the inner disc edge, and thus have polar cavities with no absorbing gas, cannot reproduce the deep, wide Na I absorption lines in FU Ori objects viewed at low inclination. We find that it is necessary to include an "inner wind" to fill this polar cavity to reproduce observations. In addition, our models assuming pure scattering source functions in the Sobolev approximation at intermediate viewing angles ($30^{\circ} \lesssim i \lesssim 60^{\circ}$) do not yield sufficiently deep line profiles. Assuming complete absorption yields better agreement with observations, but simple estimates strongly suggest that pure scattering should be a much better approximation. The discrepancy may indicate that the Sobolev approximation is not applicable, possibly due to turbulence or non-monotonic velocity fields; there is some observational evidence for the latter. Our results provide guidance for future attempts to constrain FU Ori wind properties using full MHD wind simulations, by pointing to the importance of the boundary conditions necessary to give rise to an inner wind, and by suggesting that the winds must be turbulent to produce sufficiently deep line profiles.Comment: 12 pages, 17 figures, accepted for publication in MNRA

TRADE POLICY UNDER IMPERFECT COMPETITION: AN ASSESSMENT OF THE TRQ ON LAMB MEAT

The United States imposed a tariff-rate quota (TRQ) on lamb meat in July 1999. Early analysis suggested the possibility that lamb growers could lose welfare via the creation of packer market power. This paper considers how subsequent events modify that analysis. Observed prices suggest reduced pass-through. Lamb prices are unchanged and more stable. Using an annual quota instead of a quarterly quota reduces the opportunity for market conduct switching. Early termination of the TRQ to comply with the WTO rulings magnifies any welfare loss. Assistance payments prevent welfare losses to growers with little impact on the market.International Relations/Trade, Livestock Production/Industries,

An empirical study of electricity and gas demand drivers in large food retail buildings of a national organisation

AbstractFood retail buildings account for a measurable proportion of a country's energy consumption and resultant carbon emissions so energy-operating costs are key business considerations. Increased understanding of end-use energy demands in this sector can enable development of effective benchmarking systems to underpin energy management tools. This could aid identification and evaluation of interventions to reduce operational energy demand. Whilst there are a number of theoretical and semi-empirical benchmarking and thermal modelling tools that can be used for food retail building stocks, these do not readily account for the variance of technical and non-technical factors that can influence end-use demands.This paper discusses the various drivers of energy end-uses of typical UK food retail stores. It reports on an empirical study of one organisation's hypermarket stock to evaluate the influence of various factors on annual store electricity and gas demands. Multiple regression models are discussed in the context of the development and application of a methodology for estimating annual energy end-use demand in food retail buildings. The established models account for 75% of the variation in electricity demand, 50% of the variation in gas demand in stores without CHP and 77% of the variation in gas demand in stores with CHP

Chapman-Enskog expansion about nonequilibrium states: the sheared granular fluid

The Chapman-Enskog method of solution of kinetic equations, such as the Boltzmann equation, is based on an expansion in gradients of the deviations fo the hydrodynamic fields from a uniform reference state (e.g., local equilibrium). This paper presents an extension of the method so as to allow for expansions about \emph{arbitrary}, far-from equilibrium reference states. The primary result is a set of hydrodynamic equations for studying variations from the arbitrary reference state which, unlike the usual Navier-Stokes hydrodynamics, does not restrict the reference state in any way. The method is illustrated by application to a sheared granular gas which cannot be studied using the usual Navier-Stokes hydrodynamics.Comment: 23 pages, no figures. Submited to PRE Replaced to correct misc. errors Replaced to correct misc. errors, make notation more consistant, extend discussio

Snow and ice melt flow features on Devon Island, Nunavut, Arctic Canada as possible analogs for recent slope flow features on Mars

Based on morphologic and contextual analogs from Devon Island, Arctic Canada, the recent martian slope flow features reported by Malin and Edgett are reinterpreted as being due not necessarily to groundwater seepage but possibly to snow or ice melt

Dedication of the Palomar Observatory and the Hale Telescope

The dedication of the Palomar Observatory, if it were being held in England, would be accompanied by brilliant pageantry both of the state, with its knights, heralds, pursuivants, kings at arms, admirals and captains, and of the church with its bishops, priests and deacons, crucifiers and choirs; and I am sure that we feel the quality of religion in this ceremony. We would hear the choirs chanting in antiphony that great canticle which so delights the choir boys: Benedicite, omnia opera Domini

Wearable microPosters

One barrier to communication at large face-to-face meetings, especially those focusing on scientific or technical topics, is a rapid way to understand what a person knows and thinks about before initiating a conversation. We have devised and reduced to practice an effective way to accomplish this task, the wearable microPoster. In our experience, we observed that at most scientific meetings, especially once the number of participants passed 100, it is difficult to get productive conversations started with strangers. Thus, conversations tend to initiate among people that already know one another. This tends to exclude newer participants and those who do not have formal speaking slots. The difficulty increases at informal aspects of meetings: coffee breaks, lines for meals, social events, outdoor events in which a prominent speaker might have different clothes and sunglasses and is thus rendered unknown. Poster sessions have long provided a venue for rapid communication and finding participants. These are usually the most productive parts of meetings. Our thinking evolved from jokes about sandwich board posters, in which one walks around with large posters on the front and back, to shirts with printed information. The advent of printed cloth posters provides a practical solution in which a microPoster is cut from the larger poster (ideally cloth), or printed on one or more sheets of standard paper, which are then taped together. A microPoster comprises your name, affiliation (with appropriate granularity determined by the meeting), and a graphical abstract. The goal is to identify yourself in a much more informative way than a nametag. One convenient way to present the microPoster is pinned on your back like a bib number (e.g., as in marathons or dances). We carried out a pilot with ten microPosters at a meeting of 1500 people (Figure 1), and found them to be effective at attracting useful conversation. The addition of a machine readable QR code (e.g., Salt, 2019) is a possible useful addition but we note that the expense in time, money and carbon footprint of a face-to-face meeting is better spent on face-to-face conversations