Latitudinal Variation in Seasonal Activity and Mortality in Ratsnakes (Elaphe obsoleta)

The ecology of ectotherms should be particularly affected by latitude because so much of their biology is temperature dependent. Current latitudinal patterns should also be informative about how ectotherms will have to modify their behavior in response to climate change. We used data from a total of 175 adult black ratsnakes (Elaphe obsoleta) radio tracked in Ontario, Illinois, and Texas, a latitudinal distance of \u3e 1500 km, to test predictions about how seasonal patterns of activity and mortality should vary with latitude. Despite pronounced differences in temperatures among study locations, and despite ratsnakes in Texas not hibernating and switching from diurnal to nocturnal activity in the summer, seasonal patterns of snake activity were remarkably similar during the months that snakes in all populations were active. Rather than being a function of temperature, activity may be driven by the timing of reproduction, which appears similar among populations. Contrary to the prediction that mortality should be highest in the most active population, overall mortality did not follow a clinal pattern. Winter mortality did increase with latitude, however, consistent with temperature limiting the northern distribution of ratsnakes. This result was opposite that found in the only previous study of latitudinal variation in winter mortality in reptiles, which may be a consequence of whether or not the animals exhibit true hibernation. Collectively, these results suggest that, at least in the northern part of their range, ratsnakes should be able to adjust easily to, and may benefit from, a warmer climate, although climate-based changes to the snakes\u27 prey or habitat, for example, could alter that prediction

A Wide-Field Survey of the Fornax Dwarf Spheroidal Galaxy

The results of a photometric survey of the Fornax dwarf spheroidal galaxy are presented herein. Accurate photometry in two colours (V and I) was collected over a 10 square degree area centred on the Fornax system with the aim of searching for extra-tidal structure. The data were complete to a magnitude of V=20, or approximately one magnitude brighter than the Fornax red clump stars. Stars were selected with a colour and magnitude lying near the Fornax red giant branch, thereby reducing contamination from the field star population. We were thus able to probe the outer structure of this dwarf galaxy. Immediately visible was a shell-like structure located 1.3 degrees NW from the centre of Fornax, approximately 30 arcmin beyond the nominal tidal radius at this position angle. We have measured the absolute visual magnitude of this feature to be M_V ~ -7. The feature is aligned with a previously reported shell (age approximately 2 Gyr) located near the core radius of Fornax. A statistical analysis of the extra-tidal stellar distribution further revealed two lobes situated on the Fornax minor axis which are aligned with the two shell-like features. The two-lobed structure combined with the two shells provide strong evidence that Fornax has experienced a merger event in the relatively recent past.Comment: 79 pages including 24 figures. Accepted for publication in AJ, scheduled for the March 2005 issue. Some figures are low resolution, and a full version of the paper is available at the ftp address: ftp://ftp.mso.anu.edu.au/pub/coleman

Media outlets and their moguls: why concentrated individual or family ownership is bad for editorial independence

This article investigates the levels of owner influence in 211 different print and broadcast outlets in 32 different European media markets. Drawing on the literature from industrial organisation, it sets out reasons why we should expect greater levels of influence where ownership of individual outlets is concentrated; where it is concentrated in the hands of individuals or families; and where ownership groups own multiple outlets in the same media market. Conversely, we should expect lower levels of influence where ownership is dispersed between transnational companies. The articles uses original data on the ownership structures of these outlets, and combines it with reliable expert judgments as to the level of owner influence in each of the outlets. These hypotheses are tested and confirmed in a multilevel regression model of owner influence. The findings are relevant for policy on ownership limits in the media, and for the debate over transnational versus local control of media

Wind ionization structure of the short-period eclipsing LMC Wolf-Rayet binary BAT99-129: preliminary results

BAT99-129 is a rare, short-period eclipsing Wolf-Rayet binary in the Large Magellanic Cloud. We present here medium-resolution NTT/EMMI spectra that allow us to disentangle the spectra of the two components and find the orbital parameters of the binary. We also present VLT/FORS1 spectra of this binary taken during the secondary eclipse, i.e. when the companion star passes in front of the Wolf-Rayet star. With these data we are able to extract, for the first time in absolute units for a WR+O binary, the sizes of the line emitting regions.Comment: 6 pages, 5 figures, to appear in proc. of "Close Binaries in the 21st Century: New Opportunities and Challenges", 2005 - Corrected Figure

Improved photometry of SDSS crowded field images: Structure and dark matter content in the dwarf spheroidal galaxy Leo I

We explore how well crowded field point-source photometry can be accomplished with SDSS data: We present a photometric pipeline based on DoPhot, and tuned for analyzing crowded-field images from the SDSS. Using Monte Carlo simulations we show that the completeness of source extraction is above 80% to i < 21 (AB) and a stellar surface density of about 200 sq.amin. Hence, a specialized data pipeline can efficiently be used for e.g. nearby resolved galaxies in SDSS images, where the standard SDSS photometric package Photo, when applied in normal survey mode, gives poor results. We apply our pipeline to an area of about 3.55sq.deg. around the dwarf spheroidal galaxy (dSph) Leo I, and construct a high S/N star-count map of Leo I via an optimized filter in color-magnitude space (g,r,i). Although the radial surface-density profile of the dwarf deviates from the best fit empirical King model towards outer radii, we find no evidence for tidal debris out to a stellar surface-density of 4*10^(-3) of the central value. We determine the total luminosity of Leo I, and model its mass using the spherical and isotropic Jeans equation. Assuming that 'mass follows light' we constrain a lower limit of the total mass of the dSph to be (1.7+/-0.2)*10^7 Msol. Contrary, if the mass in Leo I is dominated by a constant density dark-matter (DM) halo, then the mass within the central 12' is (2+/-0.6)*10^8 Msol. This leads to a mass-to-light ratio of >>6 (Ic_sol), and possibly >75 if the DM halo dominates the mass and extends further out than 12'. In summary, our results show that Leo I is a symmetric, relaxed and bound system; this supports the idea that Leo I is a dark-matter dominated system.Comment: 13 pages, 11 figures; accepted for publication in A

Lighting in the third dimension : laser scanning as an architectural survey and representation method

This paper proposes tridimensional (3D) laser scanning to architects and lighting designers as a lighting enquiry and visualization method for existing built environments. The method constitutes a complement to existing lighting methods by responding to limitations of photometric measurements, computer simulation and HDR imagery in surveying and visualizing light in actual buildings. The research explores advantages and limitations of 3D laser scanning in a case study addressing a vast, geometrically complex and fragmented naturally and artificially lit space. Lighting patterns and geometry of the case study are captured with a 3D laser scanner through a series of four scans. A single 3D model of the entire space is produced from the aligned and fused scans. Lighting distribution patterns are showcased in relation to the materiality, geometry and position of windows, walls, lighting fixtures and day lighting sources. Results and presented through images similar to architectural presentation drawings. More specifically, the lighting distribution patterns are illustrated in a floor plan, a reflected ceiling plan, an axonometry and a cross-section. The point cloud model of the case study is also generated into a video format representing the entire building as well as different viewpoints. The study shows that the proposed method provides powerful visualization results due to the unlimited number of images that can be generated from a point cloud and facilitates understanding of existing lighting conditions in spaces

Hamilton Standard Q-fan demonstrator dynamic pitch change test program, volume 1

Tests of a full scale variable pitch fan engine to obtain data on the structural characteristics, response times, and fan/core engine compatibility during transient changes in blade angle, fan rpm, and engine power is reported. Steady state reverse thrust tests with a take off nozzle configuration were also conducted. The 1.4 meter diameter, 13 bladed controllable pitch fan was driven by a T55 L 11A engine with power and blade angle coordinated by a digital computer. The tests demonstrated an ability to change from full forward thrust to reverse thrust in less than one (1) second. Reverse thrust was effected through feather and through flat pitch; structural characteristics and engine/fan compatibility were within satisfactory limits

Biophilic, photobiological and energy-efficient design framework of adaptive building façades for Northern Canada

This paper develops an integrated design framework of adaptive building façades (ABFs) to respond to photobiological and thermal needs of occupants, biophilic factors, energy requirements and climatic features in Northern Canada, i.e. near and above 50°N. The paper discusses the importance of biophilic and photobiological factors and ABFs to improve occupants’ health and human-nature relations and deal with the extreme climate in Northern Canada where non-adapted buildings that could negatively affect occupants’ wellbeing. The paper shows that existing ABFs must be further developed for northern applications in terms of (i) the physical structure and configuration of components (ii) the design of solar shading/louver panels to address photobiological and biophilic requirements (iii) the development of lighting adaptation scenarios to respond to biophilic and photobiological needs, local photoperiods and energy issues, and (iv) the overall biophilic quality for accessibility to natural patterns. The ABFs’ framework was developed in three phases including (1) process environmental data (2) produce adaptation scenarios, and (3) operate adaptation scenarios. The research discussed major issues of all phases that must be further studied, especially the development of hourly/daily/seasonally lighting adaptation scenarios. The paper develops a holistic parametric methodology to integrate and optimize major design variables of ABF’s components

A photobiological approach to biophilic design in extreme climates

This paper proposes the biophilic design approach as a plausible hypothesis for the challenging conditions related to living and working in extreme cold climates. Biophilic design has recently been developed to overcome the adverse effects of the built environment and to improve human well-being by redefining the human-nature relationship. Yet, biophilic design should be adapted to extreme cold climates in order to meet the biological needs of people in northern territories. This issue becomes more important when considering the availability of natural light due to the strong seasonal photoperiod and its effects on human well-being in such regions. The present paper critically reviews biophilic design patterns and identifies their main shortcomings. These shortcomings include the lack of (1) recommendations applicable to extreme cold climates (2) adaptation to the local photoperiods, and (3) a systemic framework integrated into the design process. The paper draws attention to the image-forming and non-image-forming effects of light as a basis of the human-nature design approach. In this regard, photobiological outcomes have been reviewed. Then, the paper discusses the existing lighting standards and guidelines in North America and how they have mainly been developed to fulfil the image-forming demands for light. Further efforts are needed to revise these standards with respect to the non-image-forming effects of light and the biophilic design requirements. Finally, adaptive building envelopes are presented as a hypothetical solution to optimize the biophilic qualities of buildings and address the biological needs of people living and working in extreme cold climates in northern territories