Prospects of inflation with perturbed throat geometry

We study brane inflation in a warped deformed conifold background that includes general possible corrections to the throat geometry sourced by coupling to the bulk of a compact Calabi-Yau space. We focus specifically, on the perturbation by chiral operator of dimension 3/2 in the CFT. We find that the effective potential in this case can give rise to required number of e-foldings and the spectral index $n_S$ consistent with observation. The tensor to scalar ratio of perturbations is generally very low in this scenario. The COBE normalization, however, poses certain difficulties which can be circumvented provided model parameters are properly fine tuned. We find the numerical values of parameters which can give rise to enough inflation, observationally consistent values of density perturbations, scalar to tensor ratio of perturbations and the spectral index $n_S$.Comment: 7 pages and nine figures; typos corrected, minor comments and clarifications added, revised version to appear in PL

India-Vietnam Relations: Prospects and Challenges

Introduction The India-Vietnam relationship is one of the most significant bilateral relationships in Asia, besides the India-Japan partnership. Over the years, in particular since the establishment of diplomatic relations between the two on 7 January 1972, this bilateral tie has assumed robustness in a number of areas, ranging from politico-strategic, defence to economic areas as well as culture, education, training, entrepreneurship development, etc. There have been continual exchanges of visits of top leaders between the two countries on a regular basis, further cementing the mutual ties and seeking newer means to explore the new vistas so that both can maximize mutual gains. It would not be wrong to say that no other country within the ASEAN grouping has received the kind of importance and undivided attention that Vietnam is getting from India. This is the reason that makes India-Vietnam relations something very special. DOI: 10.5281/zenodo.340592

Use of a Microphone Phased Array to Determine Noise Sources in a Rocket Plume

A 70-element microphone phased array was used to identify noise sources in the plume of a solid rocket motor. An environment chamber was built and other precautions were taken to protect the sensitive condenser microphones from rain, thunderstorms and other environmental elements during prolonged stay in the outdoor test stand. A camera mounted at the center of the array was used to photograph the plume. In the first phase of the study the array was placed in an anechoic chamber for calibration, and validation of the indigenous Matlab(R) based beamform software. It was found that the "advanced" beamform methods, such as CLEAN-SC was partially successful in identifying speaker sources placed closer than the Rayleigh criteria. To participate in the field test all equipments were shipped to NASA Marshal Space Flight Center, where the elements of the array hardware were rebuilt around the test stand. The sensitive amplifiers and the data acquisition hardware were placed in a safe basement, and 100m long cables were used to connect the microphones, Kulites and the camera. The array chamber and the microphones were found to withstand the environmental elements as well as the shaking from the rocket plume generated noise. The beamform map was superimposed on a photo of the rocket plume to readily identify the source distribution. It was found that the plume made an exceptionally long, >30 diameter, noise source over a large frequency range. The shock pattern created spatial modulation of the noise source. Interestingly, the concrete pad of the horizontal test stand was found to be a good acoustic reflector: the beamform map showed two distinct source distributions- the plume and its reflection on the pad. The array was found to be most effective in the frequency range of 2kHz to 10kHz. As expected, the classical beamform method excessively smeared the noise sources at lower frequencies and produced excessive side-lobes at higher frequencies. The "advanced" beamform routine CLEAN-SC created a series of lumped sources which may be unphysical. We believe that the present effort is the first-ever attempt to directly measure noise source distribution in a rocket plume

Structural Carbohydrates and Lignifications Associated with Submergence Tolerance in Rice (Oryza sativa L.)

Role of structural carbohydrate content and lignifications in rice shoot were studied in three indica rice (Oryza sativa L.) cultivars namely FR13A (tolerant to submergence), IR42 (susceptible to submergence) and Sabita (adapted to medium depth, 0-50 cm stagnant flooding), varying degrees of tolerance to submergence under control and 8 days after submergence conditions. During submergence, Sabita and IR 42 accelerated the rate of stem and leaf elongation more than that of FR 13A. Submergence significantly reduces the cellulose and hemicelluloses content. The decrease was more pronounced in susceptible rice cultivar than that of tolerant rice cultivar. Lignifications’ was monitored by measuring the content of lignin and the activities of two enzymes of the lignin biosynthetic pathway, coniferyl alcohol dehydrogenase (CAD) and phenylalanine ammonia-lyase (PAL) in rice shoots. Lignin content and PAL and CAD activity was more in susceptible cv. both under control and 8d after submergence. In conclusion submergence induced elongation of rice shoot might decreased the structural carbohydrate level as our experiment showed a significant negative correlation of cellulose and hemicelluloses with plant height but also positively associated with plant survival under submergence. The content of lignin and activities of CAD and PAL showed negative association with shoot elongation, yet the association of these parameters with survival was non-significant