Quantum Description for the Decay of NSNS Brane-Antibrane Systems

The stringy description for the instabilities in the $RR$ charged $D_{p}-\bar{D}_{p}$ pairs is now well understood in terms of the open string tachyon condensation. The quantum interpretation presumably via the stringy description for the instabilities in the $NSNS$-charged $F1-\bar{F1}$ and $NS5-\bar{NS5}$ pairs in IIA/IIB theories, however, has not been established yet. This would be partly because of the absence (for the $F1-\bar{F1}$ case) or our relatively poor understanding (for the $NS5-\bar{NS5}$ case) of their worldvolume (gauge theory) dynamics. In the present work, using the well-known quantum description for instabilities in the $RR$-charged $D_{p}-\bar{D}_{p}$ systems and in the M-theory brane-antibrane systems and invoking appropriate string dualities, the stringy nature of the instabilities in the $NSNS$-charged $F1-\bar{F1}$ and $NS5-\bar{NS5}$ systems has been uncovered. For the annihilations to string vacua, the quantum, stringy interpretations are simple extensions of Sen's conjecture for those in $RR$-charged brane-antibrane systems.Comment: 22 pages, 4 eps figures, Latex, comments and references adde

Dilatonic p-Branes and Brane Worlds

We study a general dilatonic p-brane solution in arbitrary dimensions in relation to the Randall-Sundrum scenario. When the p-brane is fully localized along its transverse directions, the Kaluza-Klein zero mode of bulk graviton is not normalizable. When the p-brane is delocalized along its transverse directions except one, the Kaluza-Klein zero mode of bulk graviton is normalizable if the warp factor is chosen to increase, in which case there are singularities at finite distance away from the p-brane. Such delocalized p-brane can be regarded as a dilatonic domain wall as seen in higher dimensions. This unusual property of the warp factor allows one to avoid a problem of dilatonic domain wall with decreasing warp factor that free massive particles are repelled from the domain wall and hit singularities, since massive particles with finite energy are trapped around delocalized p-branes with increasing warp factor by gravitational force and can never reach the singularities.Comment: 13 pages, LaTe

Supergravity, Non-Conformal Field Theories and Brane-Worlds

We consider the supergravity dual descriptions of non-conformal super Yang-Mills theories realized on the world-volume of Dp-branes. We use the dual description to compute stress-energy tensor and current correlators. We apply the results to the study of dilatonic brane-worlds described by non-conformal field theories coupled to gravity. We find that brane-worlds based on D4 and D5 branes exhibit a localization of gauge and gravitational fields. We calculate the corrections to the Newton and Coulomb laws in these theories.Comment: 24 pages, Latex, 2 figure

A note on brane cosmology

We derive a new class of time-dependent solutions for the Randall-Sundrum model by patching together isometries broken by the brane. Solutions generated by generalized boosts along the fifth dimension are associated with localized gravity and lead to an effective Friedman equation on the brane with a scale factor exhibiting power law or exponential behaviour. The effective energy-density on the brane depends linearly on the brane tension.Comment: 10 pages, references adde

Panicle insect pests of sorghum and pearl millet:proceedings of an International Consultative Workshop 4-7 Oct 1993 ICRISAT Sahelian Center Niamey, Niger

This workshop brought together national and international scientists from 12 countries to assess the economic importance of panicle-feeding insect pests of sorghum and pearl millet worldwide and review existing knowledge; provide concise and up-to-date information on current research on management tactics; develop research themes and priorities for their management in various cropping systems and agroecologies; and develop/strengthen linkages and enhance collaboration and partnership between international agricultural research systems, universities, and NARS, in order to achieve more effective technology transfer, resulting in increased and sustained productivity on farmers' fields. The sessions covered bioecology and crop losses, and management strategies (including host-plant resistance, crop management and biological control, and integrated pest management). Regional reports were presented from western, eastern, and southern Africa, Asia, and the Western Hemisphere. Discussions of working groups and recommendations are included. Presentations are reproduced in the original language of submission (English/French), followed by an extended swnmary in French/English as the case may be. The opening session addresses, objectives, discussions at the end of each session, general discussion session, and recommendations are in both language

A Bestiary of Higher Dimensional Taub-NUT-AdS Spacetimes

We present a menagerie of solutions to the vacuum Einstein equations in six, eight and ten dimensions. These solutions describe spacetimes which are either locally asymptotically adS or locally asymptotically flat, and which have non-trivial topology. We discuss the global structure of these solutions, and their relevance within the context of M-theory.Comment: 11 pages, LaTex(v4: Comments and references added

Low Energy Branes, Effective Theory and Cosmology

The low energy regime of cosmological BPS-brane configurations with a bulk scalar field is studied. We construct a systematic method to obtain five-dimensional solutions to the full system of equations governing the geometry and dynamics of the bulk. This is done for an arbitrary bulk scalar field potential and taking into account the presence of matter on the branes. The method, valid in the low energy regime, is a linear expansion of the system about the static vacuum solution. Additionally, we develop a four-dimensional effective theory describing the evolution of the system. At the lowest order in the expansion, the effective theory is a bi-scalar tensor theory of gravity. One of the main features of this theory is that the scalar fields can be stabilized naturally without the introduction of additional mechanisms, allowing satisfactory agreement between the model and current observational constraints. The special case of the Randall-Sundrum model is discussed.Comment: 19 pages, 4 figure

An improved infestation technique using eggs of the millet head miner (Heliocheilus albipunctella) (Lepidoptera: Noctuidae) in millet resistance screening

The millet head miner moth, H. albipunctella, is an important pest of pearl millet, Pennisetum glaucum, in Sub-Saharan Africa and causes severe crop losses. Damage to the panicles is direct and caused by developing larvae. Management techniques are being developed among which is host plant resistance. Youm and Kumar (1995) reported little progress in identifying resistance due to lack of a repeatable and reliable screening method. Efforts for the past 5 years have been devoted to developing such a technique. Youm (1997) reported an improved technique based on the use of larvae where 35-45 larvae were efficient in causing 51-60% damage corresponding to a rating of 6 on a susceptible genotype. Though the use of larvae was promising, the present research shows that the use of eggs is more efficient than using neonate larvae. The use of 40 eggs per panicle resulted in 51-80% damage corresponding to a mean damage rating ranging from 5.5 to 8.4 across several genotypes. A higher and more consistent infestation was obtained with eggs than larvae. Finally, egg handling was easier and infestation cheaper than using larvae. This technique should significantly improve screening millet for reaction to the head miner. It is recommended for use for future resistance screening of genotypes against the millet head miner to avoid the release of highly susceptible varieties on-farm