Triggering of Imaging Air Cherenkov Telescopes: PMT trigger rates due to night-sky photons

Imaging air Cherenkov telescopes are usually triggered on a coincidence of two or sometimes more pixels, with discriminator thresholds in excess of 20 photoelectrons applied for each pixel. These thresholds required to suppress night-sky background are significantly higher than expected on the basis of a Poisson distribution in the number of night-sky photoelectrons generated during the characteristic signal integration time. We studied noise trigger rates under controlled conditions using an artificial background light source. Large tails in the PMT amplitude response to single photoelectrons are identified as a dominant contribution to noise triggers. The rate of such events is very sensitive to PMT operating parameters.Comment: 19 pages, latex,epsf, 7 figures appended as uuencoded file, submitted to Journal of Physics

Applications of prestressed segmented brittle materials in aerospace structures

Prestressed segmented brittle materials in aerospace structure

High performance structures

Materials selection, structural geometry, proof testing and statistical screening, prestressing, and system energy as tools for designing optimum trusses and other high performance structure

Studies in prestressed and segmented brittle structures

Application of nonlinear bending theory to prestressed and segmented brittle structure

On Keller Theorem for Anisotropic Media

The Keller theorem in the problem of effective conductivity in anisotropic two-dimensional (2D) many-component composites makes it possible to establish a simple inequality $\sigma_{{\sf is}}^e(\sigma^{-1}_i)\cdot \sigma_{{\sf is}}^e(\sigma_k)> 1$ for the isotropic part $\sigma_{{\sf is}}^e(\sigma_k)$ of the 2-nd rank symmetric tensor ${\widehat \sigma}_{i,j}^e$ of effective conductivity.Comment: 1 page, 1 figur

Cancer therapeutic potential of combinatorial immuno- and vaso-modulatory interventions

Currently, most of the basic mechanisms governing tumor-immune system interactions, in combination with modulations of tumor-associated vasculature, are far from being completely understood. Here, we propose a mathematical model of vascularized tumor growth, where the main novelty is the modeling of the interplay between functional tumor vasculature and effector cell recruitment dynamics. Parameters are calibrated on the basis of different in vivo immunocompromised Rag1-/- and wild-type (WT) BALB/c murine tumor growth experiments. The model analysis supports that tumor vasculature normalization can be a plausible and effective strategy to treat cancer when combined with appropriate immuno-stimulations. We find that improved levels of functional tumor vasculature, potentially mediated by normalization or stress alleviation strategies, can provide beneficial outcomes in terms of tumor burden reduction and growth control. Normalization of tumor blood vessels opens a therapeutic window of opportunity to augment the antitumor immune responses, as well as to reduce the intratumoral immunosuppression and induced-hypoxia due to vascular abnormalities. The potential success of normalizing tumor-associated vasculature closely depends on the effector cell recruitment dynamics and tumor sizes. Furthermore, an arbitrary increase of initial effector cell concentration does not necessarily imply a better tumor control. We evidence the existence of an optimal concentration range of effector cells for tumor shrinkage. Based on these findings, we suggest a theory-driven therapeutic proposal that optimally combines immuno- and vaso-modulatory interventions

Green-house construction

Citation: Haffner, Hermann C. Green-house construction. Senior thesis, Kansas State Agricultural College, 1900.Morse Department of Special CollectionsIntroduction: While the various glass structures are generally distinguished according to their use, as Rose houses, Palm houses, Store houses, Graperies, etc., for our present purpose, it will be well to first consider them from the builder’s standpoint, as lean-to, span roof, etc. These names have been applied from the various shapes that may be given to the houses. While any of these forms may be used for all purposes, each one of them is particularly adapted to the growth of certain plants; and as they each have their special advantages and disadvantages, they should all be considered. However, as the space is too limited for the treatment of all the various forms, I will consider simply the construction of an even span house. When erected in connection with some other building, the aspect and slope cannot always be regulated; but, when possible, greenhouses for this purpose should be on the south slope, so that no ray of light or heat will be cut off, either from the east or west. If against some other structure, it should be built north and south, with its north end next the other building. When locating a detached house, a level spot is not objectionable, if good drainage can be secured; but if it can be located at the top of a south and westerly slope, it is all the better, as there the sun is available for extra hours at both ends of the day. If the spot chosen is not level, it should be graded, if possible. A slope of two or three inches to sixty feet is not objectionable, for it will serve to carry off the drain from the gutters; and in a group of houses, while it is preferable that each house should be practically level, if the land selected cannot be readily graded so as to bring the house on the same level, there would be no serious objection to having the houses ranged one above the other, in regular tiers