Fatigue testing device Patent

Fatigue testing device applying random discrete load levels to test specimen and applicable to aircraft structure

BEYOND THE MODEL SPECIFICATION PROBLEM: MODEL AND PARAMETER AVERAGING USING BAYESIAN TECHNIQUES

The model specification problem is perhaps the Achilles heel of applied econometrics. Rather than test down to a single model as is usually done, we estimate 72 different demand systems and use Bayesian averaging procedures over all 72 systems to generate meta estimates of the parameters (e.g., elasticities) of interest.Research Methods/ Statistical Methods,

CONTRACT MARKET VIABILITY

Academia and the finance industry generate many proposals for new contract markets. Unfortunately, many proposed markets lack the critical attributes that promote success. We examine these attributes, and evaluate the potential of several announced proposals. We find that proposals emanating from the academy generally fail to consider the full suite of integrated financial services necessary to support a viable market, while proposals put forward by practitioners are much more likely to do so.Marketing,

Calibrated Sub-Bundles in Non-Compact Manifolds of Special Holonomy

This paper is a continuation of math.DG/0408005. We first construct special Lagrangian submanifolds of the Ricci-flat Stenzel metric (of holonomy SU(n)) on the cotangent bundle of S^n by looking at the conormal bundle of appropriate submanifolds of S^n. We find that the condition for the conormal bundle to be special Lagrangian is the same as that discovered by Harvey-Lawson for submanifolds in R^n in their pioneering paper. We also construct calibrated submanifolds in complete metrics with special holonomy G_2 and Spin(7) discovered by Bryant and Salamon on the total spaces of appropriate bundles over self-dual Einstein four manifolds. The submanifolds are constructed as certain subbundles over immersed surfaces. We show that this construction requires the surface to be minimal in the associative and Cayley cases, and to be (properly oriented) real isotropic in the coassociative case. We also make some remarks about using these constructions as a possible local model for the intersection of compact calibrated submanifolds in a compact manifold with special holonomy.Comment: 20 pages; for Revised Version: Minor cosmetic changes, some paragraphs rewritten for improved clarit

Neighborhoods of trees in circular orderings

In phylogenetics, a common strategy used to construct an evolutionary tree for a set of species X is to search in the space of all such trees for one that optimizes some given score function (such as the minimum evolution, parsimony or likelihood score). As this can be computationally intensive, it was recently proposed to restrict such searches to the set of all those trees that are compatible with some circular ordering of the set X. To inform the design of efficient algorithms to perform such searches, it is therefore of interest to find bounds for the number of trees compatible with a fixed ordering in the neighborhood of a tree that is determined by certain tree operations commonly used to search for trees: the nearest neighbor interchange (nni), the subtree prune and regraft (spr) and the tree bisection and reconnection (tbr) operations. We show that the size of such a neighborhood of a binary tree associated with the nni operation is independent of the tree’s topology, but that this is not the case for the spr and tbr operations. We also give tight upper and lower bounds for the size of the neighborhood of a binary tree for the spr and tbr operations and characterize those trees for which these bounds are attained

Population Growth Characteristics of Incipient Colonies of the Eastern Subterranean Termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae)

Growth of Reticulitermes flavipes (Kollar) incipient colonies during their first year was documented via a monthly destructive sampling census of 15 unique colonies, each headed by an inbred primary pair, for a total of 180 colonies. King and queen biomass greatly decreased during the first 2 months, coinciding with egg production and colony foundation, but their biomass remained relatively constant thereafter. Three cohorts of eggs were produced, with the greatest number of eggs (mean = 14.5) during the first month. Larvae were present at 1 month, and workers were first observed at 2 months. The survival rate of the initial brood was less than 100%, most likely due to cannibalism. A single soldier was first noted in some colonies at 6 months. Offspring biomass was equal to that of the reproductive pair at the 2-month census, double at 3 months, and quadruple at 11 months. One-year-old colonies ranged in size from 20 to 40 individuals, with an average of 28.9 individuals; total colony biomass was 39.8 mg. The growth rate of these R. flavipes colonies was much slower than was reported in other studies, but our observations are consistent with previous models and suggestions regarding colony growth

Distribution and Reproduction by the Purple Gallinule (Porphyrio martinica) in Arkansas

The Purple Gallinule (Porphyrio martinica) is a rare bird in Arkansas, and its populations likely have declined due to loss of marshy areas with emergent vegetation. By use of online sources for citizen science combined with a field study, we elucidate the current distribution of this bird in Arkansas, and document characteristics of reproduction and development. Purple Gallinules arrive in Arkansas as early as April and remain to late October. Nesting occurs from early May into July, and nests may represent second broods. Ontogenetic changes in hatchlings are described