D-instanton sums for matter hypermultiplets

We calculate some non-perturbative (D-instanton) quantum corrections to the moduli space metric of several (n>1) identical matter hypermultiplets for the type-IIA superstrings compactified on a Calabi-Yau threefold, near conifold singularities. We find a non-trivial deformation of the (real) 4n-dimensional hypermultiplet moduli space metric due to the infinite number of D-instantons, under the assumption of n tri-holomorphic commuting isometries of the metric, in the hyper-K"ahler limit (i.e. in the absence of gravitational corrections).Comment: 11 pages, no figure

Construction and Validation of Biology Assessment Test (BAT) for Junior High School Students

This test development study aims to develop and validate an achievement test in Biology designed for junior high school completers. Test items were pooled from selected lessons in Biology. The researchers prepared a table of specification (TOS) and subjected the102- item multiple choice type of examination to validation by experts. After the initial validation, the test had 88 items that were pilot tested among 172 grade 11 students at a private university. The researcher did item analysis which classified 67 items as "average," 21 as "hard," none as" easy," 10 as "very good", 12 as "good," 19 as “fair” and 47 as "poor." Consistency and reliability were obtained using Kuder-Richardson (KR) 20. A total of 22 items were retained of the 88 based on validation and item analysis. Three items that were initially classified as "fair" and with "marginal" difficulty index were revised to produce a 25-item final version of the Biology Achievement Test

Complete Calabi-Yau metrics from Kahler metrics in D=4

In the present work the local form of certain Calabi-Yau metrics possessing a local Hamiltonian Killing vector is described in terms of a single non linear equation. The main assumptions are that the complex $(3,0)$-form is of the form $e^{ik}\widetilde{\Psi}$, where $\widetilde{\Psi}$ is preserved by the Killing vector, and that the space of the orbits of the Killing vector is, for fixed value of the momentum map coordinate, a complex 4-manifold, in such a way that the complex structure of the 4-manifold is part of the complex structure of the complex 3-fold. The link with the solution generating techniques of [26]-[28] is made explicit and in particular an example with holonomy exactly SU(3) is found by use of the linearization of [26], which was found in the context of D6 branes wrapping a holomorphic 1-fold in a hyperkahler manifold. But the main improvement of the present method, unlike the ones presented in [26]-[28], does not rely in an initial hyperkahler structure. Additionally the complications when dealing with non linear operators over the curved hyperkahler space are avoided by use of this method.Comment: Version accepted for publication in Phys.Rev.