Some factors influencing populations of the European corn borer, Ostrinia nubilalis (Hubner) in the north central states: Resistance of corn, time of planting and weather conditions Part II, 1958-1962

A cooperative project was conducted by the agricultural experiment stations of Iowa, Minnesota and Ohio and the U. S. Department of Agriculture to study the effects of weather, planting date and resistant hybrids as factors influencing populations of the European com borer, Ostrinia nubilalis (Hübner). Identical studies were carried out at Ankeny, Iowa; Waseca, Minnesota; and Wooster, Ohio, during a 10-year period, 1953-1962. The first 4 years of the study (1953-56) were reported by Everett et al. (1958). The work reported herein is a companion bulletin to the Everett et al. (1958) publication and deals with the results of experiments conducted during 1958-1962. The experimental design was a randomized block, split plot with five replications. The whole plot treatments were four hybrid-planting date combinations consisting of early- or late-planting dates and susceptible or resistant hybrids. The subplot treatments consisted of a factorial arrangement of all possible combinations of three levels of infestation (zero, natural and natural + 3 egg masses) by first brood and the same three levels of infestation by second-brood borers. Temperature and rainfall records were kept at each of the three stations. Borer population and injury to the plant were recorded at the end of the first brood and in the fall. Yield data were collected

European Corn Borer, Ostrinia nubilalis (Hbn.) Populations in Field Corn, Zea mays (L.) in the North Central United States

A long-range study of the annual changes in corn borer populations in the North Central States was started in Minnesota, Iowa, Kansas and Nebraska in 1955 and in Missouri and Ohio in 1956. This investigation was a phase of a broader Regional Project, NC-20, entitled Factors Influencing Corn Borer Populations and was undertaken to measure by standardized procedures the seasonal changes in abundance of the European corn borer, Ostrinia nubilalis (Hbn.), under cropping procedures in different locations within, the North Central States. Much valuable information has been accumulated on the abundance and effects of various physical and biotic factors on corn borer populations. Results obtained from 1955 through 1959 are summarized in a regional publication (Chiang et al. 1961). The present compilation and summary is offered as a companion bulletin containing data for the years 1960 through 1964. Although the primary purpose of the present bulletin is to present results for the 1960 to 1964 period, it seemed pertinent to include statements of comparison with the preceding 5-year\u27s work and to analyze in a rather gross way certain aspects of the population changes for the entire 10-year period. Studies of this nature are long-time projects requiring many years of work in order to evaluate population fluctuations and factors influencing them. Hence the examination of the recent 5-year period becomes more meaningful when compared with the previous 5-year period or when considered as a single 10-year period

Symplectic potentials and resolved Ricci-flat ACG metrics

We pursue the symplectic description of toric Kahler manifolds. There exists a general local classification of metrics on toric Kahler manifolds equipped with Hamiltonian two-forms due to Apostolov, Calderbank and Gauduchon(ACG). We derive the symplectic potential for these metrics. Using a method due to Abreu, we relate the symplectic potential to the canonical potential written by Guillemin. This enables us to recover the moment polytope associated with metrics and we thus obtain global information about the metric. We illustrate these general considerations by focusing on six-dimensional Ricci flat metrics and obtain Ricci flat metrics associated with real cones over L^{pqr} and Y^{pq} manifolds. The metrics associated with cones over Y^{pq} manifolds turn out to be partially resolved with two blowup parameters taking special (non-zero)values. For a fixed Y^{pq} manifold, we find explicit metrics for several inequivalent blow-ups parametrised by a natural number k in the range 0<k<p. We also show that all known examples of resolved metrics such as the resolved conifold and the resolution of C^3/Z_3 also fit the ACG classification.Comment: LaTeX, 34 pages, 4 figures (v2)presentation improved, typos corrected and references added (v3)matches published versio

A Note on Einstein Sasaki Metrics in D \ge 7

In this paper, we obtain new non-singular Einstein-Sasaki spaces in dimensions D\ge 7. The local construction involves taking a circle bundle over a (D-1)-dimensional Einstein-Kahler metric that is itself constructed as a complex line bundle over a product of Einstein-Kahler spaces. In general the resulting Einstein-Sasaki spaces are singular, but if parameters in the local solutions satisfy appropriate rationality conditions, the metrics extend smoothly onto complete and non-singular compact manifolds.Comment: Latex, 13 page

Supersymmetric AdS_5 Solutions of Type IIB Supergravity

We analyse the most general bosonic supersymmetric solutions of type IIB supergravity whose metrics are warped products of five-dimensional anti-de Sitter space AdS_5 with a five-dimensional Riemannian manifold M_5. All fluxes are allowed to be non-vanishing consistent with SO(4,2) symmetry. We show that the necessary and sufficient conditions can be phrased in terms of a local identity structure on M_5. For a special class, with constant dilaton and vanishing axion, we reduce the problem to solving a second order non-linear ODE. We find an exact solution of the ODE which reproduces a solution first found by Pilch and Warner. A numerical analysis of the ODE reveals an additional class of local solutions.Comment: 33 page

Eguchi-Hanson Solitons in Odd Dimensions

We present a new class of solutions in odd dimensions to Einstein's equations containing either a positive or negative cosmological constant. These solutions resemble the even-dimensional Eguchi-Hanson-(A)dS metrics, with the added feature of having Lorentzian signatures. They are asymptotic to (A)dS$_{d+1}/Z_p$. In the AdS case their energy is negative relative to that of pure AdS. We present perturbative evidence in 5 dimensions that such metrics are the states of lowest energy in their asymptotic class, and present a conjecture that this is generally true for all such metrics. In the dS case these solutions have a cosmological horizon. We show that their mass at future infinity is less than that of pure dS.Comment: 26 pages, Late