D-instantons probing D3-branes and the AdS/CFT correspondence

D-instantons are considered as a probe of coinciding $N$ D3-branes. They can feel an external metric via the commutator terms in their effective action. We show that when the D-instantons are separated from the D3-branes, the metric which is probed at the one loop level, {\it exactly} coincides with that of the BPS R-R 3-brane. Interesting connection of this result to the possible explanation of the AdS/CFT correspondence within IKKT M-atrix theory is discussed.Comment: 8pp., Latex. Minor changes, misprints are correcte

Measuring the Effects of “Opportunistic Defense” of the Bracken Fern, \u3ci\u3e(Pteridium Aquilinum)\u3c/i\u3e by Patrolling Ants (Hymenoptera: Formicidae) at Pierce Cedar Creek Institute in South Central Michigan

In this study we show that in South Central Michigan (Pierce Cedar Creek Institute) eight ant species patrol bracken fern (Pteridium aquilinum) during the sensitive crozier growth stage. At times these ants remove herbivorous insects from rapidly expanding fronds. A new method for analyzing herbivory of bracken fern is employed to measure chewing damage to the fronds. Our results show that ants do in fact remove some herbivores from bracken fronds during the crozier stage; however, statistical analyses comparing the amount of chewing damage between treated and untreated fronds at the end of the growing season show no statistical difference

Parasitism of \u3ci\u3ePlathypena Scabra\u3c/i\u3e (Lepidoptera: Noctuidae) by \u3ci\u3eSinophorus Teratis\u3c/i\u3e (Hymenoptera: Ichneumonidae)

(excerpt) A study was conducted at the Ecology Research Center, Miami University, Butler County, Ohio, during the summer of 1990 to examine the effects of strip intercropping sorghum and soybean on the occurrence of parasitoids and incidence of disease in larvae ofthe green cloverworm, Plathypena scabra (F.) (Lepidoptera: Noctuidae), a sporadic pest of soybeans. The details of the experimental design and results are reported elsewhere (Williams et al. 1995)

Effects of Dredge Material Placement on Macroinvertebrate Communities: Phase 1

ID: 8809; issued October 1, 1998INHS Technical Report prepared for Rock Island District, US Army Corps of Engineer

The effect of elevated hydrostatic pressure on the spectral absorption of deep-sea fish visual pigments

The effect of hydrostatic pressure (0.1-54 MPa, equivalent to pressures experienced by fish from the ocean's surface to depths of ca. 5400 m) on visual pigment absorption spectra was investigated for rod visual pigments extracted from the retinae of 12 species of deep-sea fish of diverse phylogeny and habitat. The wavelength of peak absorption (λmax) was shifted to longer wavelengths by an average of 1.35 nm at 40 MPa (a pressure approximately equivalent to average ocean depth) relative to measurements made at one atmosphere (ca. 0.1 MPa), but with little evidence of a change in absorbance at the λmax. We conclude that previousλ max measurements of deep-sea fish visual pigments, made at a pressure close to 0.1 MPa, provide a good indication ofλ max values at higher pressures when considering the ecology of vision in the deep-sea. Although not affecting the spectral sensitivity of the animal to any important degree, the observed shift inλ max may be of interest in the context of understanding opsin-chromophore interaction and spectral tuning of visual pigments

The effect of environmental plasma interactions on the performance of the solar sail system

Interaction between the solar sail and the natural plasma environment were examined for deleterious impacts upon the operation of the sail and its associated payload. Electrostatic charging of the sail in the solar wind and in near earth environment were examined. Deployment problems were studied. An analysis of electromechanical oscillations coupling the sail to the natural plasma was performed. As a result of these studies, it was concluded that none of these effects will have a significant negative impact upon the sail operation. The natural environment will be significantly perturbed and this will preclude measurements of electric and magnetic fields from an attached payload

Tachyon-Free Non-Supersymmetric Strings on Orbifolds

We discuss tachyon-free examples of (Type IIB on) non-compact non-supersymmetric orbifolds. Tachyons are projected out by discrete torsion between orbifold twists, while supersymmetry is broken by a Scherk-Schwarz phase (+1/-1 when acting on space-time bosons/fermions) accompanying some even order twists. The absence of tachyons is encouraging for constructing non-supersymmetric D3-brane gauge theories with stable infrared fixed points. The D3-brane gauge theories in our orbifold backgrounds have chiral N = 1 supersymmetric spectra, but non-supersymmetric interactions.Comment: 17 page

Domain Walls on Singularities

We describe domain walls that live on $A_2$ and $A_3$ singularities. The walls are BPS if the singularity is resolved and non--BPS if it is deformed and fibered. We show that these domain walls may interpolate between vacua that support monopoles and/or vortices.Comment: 16 pages in phyzzx.te