Novel applications of plant tissue culture and conventional breeding techniques to space biology research

In the minds of many, plant cell and tissue culture may now be viewed as a well-developed technology. It has been all but reduced to a tool to solve practical problems and contribute to plant improvement. While this is so in some instances, it is definitely not so in trying to utilize and integrate plant cell and tissue culture into the projected needs of Space biology programs. This is not merely because of the challenges posed by the unusual physical environment of Space such as microgravity, or the constraints posed by Spaceflight protocols but is due to our inadequate knowledge of the factors that control plant growth and development, including systems as they grow in vitro. The premature (and in many cases unrealistically optimistic) initial assessments of what is really known about what happens in aseptic culture belies the many fundamental developmental and physiological questions that still need to be answered before plan

Constructing Involutive Tableaux with Guillemin Normal Form

Involutivity is the algebraic property that guarantees solutions to an analytic and torsion-free exterior differential system or partial differential equation via the Cartan-K\"ahler theorem. Guillemin normal form establishes that the prolonged symbol of an involutive system admits a commutativity property on certain subspaces of the prolonged tableau. This article examines Guillemin normal form in detail, aiming at a more systematic approach to classifying involutive systems. The main result is an explicit quadratic condition for involutivity of the type suggested but not completed in Chapter IV, \S 5 of the book Exterior Differential Systems by Bryant, Chern, Gardner, Goldschmidt, and Griffiths. This condition enhances Guillemin normal form and characterizes involutive tableaux.Comment: This article co-evolved with "Degeneracy of the Characteristic Variety," arXiv:1410.6947 and most notation is shared. However, be aware that the meaning of the indices i,j,k,l and the space Y is not the same between these article

The Presidency, War, and Foreign Affairs: Practice Under the Framers

Varje år träder ca 50 000 människor ur Svenska kyrkan och avsäger sig därmed rätten att begravas i Svenska kyrkans ceremoniella ordning och lokaler. Man träder ut ur kyrkans ordning, och ut ur kyrkans rum, men man träder inte in i något annat. Mitt kandidatarbete är ett försök att visa på en annan ordning och andra rum. Every year some 50 000 people exits the Swedish Church and disclaims thus the right to be buried in the Swedish Church ceremonial order and premises. They leave behind the order of the Church, and exits the church room, but they do not enter anything else. My graduate work is an attempt to present an alternative order and alternative rooms

Wind-wind collision in the eta Carinae binary system - III. The HeII 4686 line profile

We modeled the HeII 4686 line profiles observed in the eta Carinae binary system close to the 2003.5 spectroscopic event, assuming that they were formed in the shocked gas that flows at both sides of the contact surface formed by wind-wind collision. We used a constant flow velocity and added turbulence in the form of a gaussian velocity distribution. We allowed emission from both the primary and secondary shocks but introduced infinite opacity at the contact surface, implying that only the side of the contact cone visible to the observer contributed to the line profile. Using the orbital parameters of the binary system derived from the 7 mm light curve during the last spectroscopic event (Paper II) we were able to reproduce the line profiles obtained with the HST at different epochs, as well as the line mean velocities obtained with ground based telescopes. A very important feature of our model is that the line profile depends on the inclination of the orbital plane; we found that to explain the latitude dependent mean velocity of the line, scattered into the line of sight by the Homunculus, the orbit inclination should be close to 90 degrees, meaning that it does not lie in the Homunculus equatorial plane, as usually assumed. This inclination, together with the relative position of the stars during the spectroscopic events, allowed us to explain most of the observational features, like the variation of the Purple Haze with the orbital phase, and to conciliate the X-ray absorption with the postulated shell effect used to explain the optical and UV light curves.Comment: to appear in the MNRA

Tubule density at different sample sites around the stratum medium of horse hoof horn

Microscopic analysis shows that equine hoof wall is composed of distinct phases of tubular and intertubular horn. The tubule density (TD) of hoof horn is found by ascertaining the number of tubules per unit area and is believed to relate to mechanical properties, resistance to wear, “quality”, hardness and moisture content. The straight grid previously used to ascertain the TD of hoof horn may omit certain tubules on both the inner and outer hoof wall as the wall itself is curved. This present study examined whether there was a significant difference in results for TD between using the conventional straight grid method and a novel method using a curved grid. TD was also compared across three sample sites. An analysis of TD from four equal sections (zones) across the hoof wall was also carried out