Information control in reputational cheap talk

An evaluator estimates as precisely as possible the innate talent of a careerist expert by observing the expert's performance in a prediction task, and has the ability to interfere with the expert's private signal by affecting its precision. The expert on the other hand knows her talent, observes this interference and can misrepresent private beliefs through strategic predictions to enhance her reputation. We show that when priors are significantly uninformative so that the task is a priori hard, the evaluator reduces the precision of the expert's signal, while when priors are significantly informative, he enhances it. We also find that the evaluator's objectives of maximising the precision of information about talent and maximising the probability of ‘truthful expert advice’ in the given task are aligned in and only in a priori hard tasks. We discuss implications of these results for market research decisions by a monopolist facing uncertain demand

A record production from an integrated farming system utilising sewage enriched water

The results of experiments conducted on a pond dyke (655m²) in the Wastewater Aquaculture Division of the Central Institute of Freshwater Aquaculture, Rahara, during 1992-93 for maximising production through optimum utilisation of resources are communicated. Round the year intensive cultivation of okra (Abelmoschus esculentus), amaranth (Amaranthus gangeticus and A. viridus), water-bind weed (Ipomea aquatica), Indian spinach (Basella rubra), radish (Raphanus sativum), amaranth (Amaranthus viridis), cauliflower (Brassica oleracia var. votrytis), cabbage (Brassica oleracia var. capitota) and papaya (Carica papaya) was undertaken using the treated sewage water from fish ponds for irrigation. The pond dyke yielded 5,626.5 kg vegetable which worked out to 85.9 tons per ha per year. Multiple cropping with these vegetables excluding papaya on a 460 m² dyke recorded a production of 4,926.5 kg at the rate of 107.1t per ha/yr. An improved yearly net return of about 35% over investment could be achieved through the selection of highly productive and pest resistant vegetable crops of longer duration for integration into the system. Introduction of this type of integrated farming would enhance the overall productivity and returns from farming

Utilisation of vegetable leaves for carp production

The results of two sets of experiments on mono-culture of grass carp (Ctenopharyngodon idella) and mixed culture of carps (grass carp 50 : catla 20 : rohu 15 : mrigal 15) fed exclusively with vegetable leaves are reported. The experiments were conducted with two replicates each in 0.02 ha ponds of Wastewater Aquaculture Division of the Central Institute of Freshwater Aquaculture, Rahara during 1991-93. Monoculture of grass carp stocked at 1000/ha demonstrated an average net production of 21.0 kg/ 0.02 ha/8 months (1501 kg/ha/yr). Mixed culture of carps stocked at 5000 /ha recorded an average net production of 22.5 kg/0.02 ha/8 months (1903.7 kg/ha/yr). Field studies revealed that water bind weed (Ipomoea aquatica) is the most preferred feed of grass carp amongst vegetable leaves followed by amaranths (Amaranthus gangeticus and Amaranthus viridis), cauliflower (Brassica oleracia var. votrytis) and cabbage (Brassica oleracia var. capitata) leaves. Through selection of highly productive leaf vegetables and suitable crop planning on fallow fish pond dykes, round the year feeding programme of grass carp has been explored. Recycling of sewage effluent for vegetable production and utilisation of vegetable leaves for fish production is considered an ideal way of integrated resource management for low cost production

Rotating metrics admitting non-perfect fluids in General Relativity

In this paper, by applying Newman-Janis algorithm in spherical symmetric metrics, a class of embedded rotating solutions of field equations is presented. These solutions admit non-perfect fluidsComment: LaTex, 39 page

Remarks on 't Hooft's Brick Wall Model

A semi-classical reasoning leads to the non-commutativity of the space and time coordinates near the horizon of Schwarzschild black hole. This non-commutativity in turn provides a mechanism to interpret the brick wall thickness hypothesis in 't Hooft's brick wall model as well as the boundary condition imposed for the field considered. For concreteness, we consider a noncommutative scalar field model near the horizon and derive the effective metric via the equation of motion of noncommutative scalar field. This metric displays a new horizon in addition to the original one associated with the Schwarzschild black hole. The infinite red-shifting of the scalar field on the new horizon determines the range of the noncommutativ space and explains the relevant boundary condition for the field. This range enables us to calculate the entropy of black hole as proportional to the area of its original horizon along the same line as in 't Hooft's model, and the thickness of the brick wall is found to be proportional to the thermal average of the noncommutative space-time range. The Hawking temperature has been derived in this formalism. The study here represents an attempt to reveal some physics beyond the brick wall model.Comment: RevTeX, 5 pages, no figure

On the Crustal Matter of Magnetars

We have investigated some of the properties of dense sub-nuclear matter at the crustal region (both the outer crust and the inner crust region) of a magnetar. The relativistic version of Thomas-Fermi (TF) model is used in presence of strong quantizing magnetic field for the outer crust matter. The compressed matter in the outer crust, which is a crystal of metallic iron, is replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells. In the inner crust region, a mixture of iron and heavier neutron rich nuclei along with electrons and free neutrons has been considered. Conventional Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used for the nuclear mass formula. A lot of significant changes in the characteristic properties of dense crustal matter, both at the outer crust and the inner crust, have been observed.Comment: 29 pages REVTEX manuscript, 15 .eps figures (included

Black Hole Entropy: From Shannon to Bekenstein

In this note we have applied directly the Shannon formula for information theory entropy to derive the Black Hole (Bekenstein-Hawking) entropy. Our analysis is semi-classical in nature since we use the (recently proposed [8]) quantum mechanical near horizon mode functions to compute the tunneling probability that goes in to the Shannon formula, following the general idea of [5]. Our framework conforms to the information theoretic origin of Black Hole entropy, as originally proposed by Bekenstein.Comment: 9 pages Latex, Comments are welcome; Thoroughly revised version, reference and acknowledgements sections enlarged, numerical error in final result corrected, no major changes, to appear in IJT

Higher order WKB corrections to black hole entropy in brick wall formalism

We calculate the statistical entropy of a quantum field with an arbitrary spin propagating on the spherical symmetric black hole background by using the brick wall formalism at higher orders in the WKB approximation. For general spins, we find that the correction to the standard Bekenstein-Hawking entropy depends logarithmically on the area of the horizon. Furthermore, we apply this analysis to the Schwarzschild and Schwarzschild-AdS black holes and discuss our results.Comment: 21 pages, published versio

(Twisted) Toroidal Compactification of pp-Waves

The maximally supersymmetric type IIB pp-wave is compactified on spatial circles, with and without an auxiliary rotational twist. All spatial circles of constant radius are identified. Without the twist, an S$^1$ compactification can preserve 24, 20 or 16 supercharges. $T^2$ compactifications can preserve 20, 18 or 16 supercharges; $T^3$ compactifications can preserve 18 or 16 supercharges and higher compactifications preserve 16 supercharges. The worldsheet theory of this background is discussed. The T-dual and decompactified type IIA and M-theoretic solutions which preserve 24 supercharges are given. Some comments are made regarding the AdS parent and the CFT description.Comment: 22 pages REVTeX 4 and AMSLaTeX. v3: References and a paragraph on nine dimensional Killing spinors were added. v4: A few typos corrected and a footnote was modifie

Warm stellar matter with deconfinement: application to compact stars

We investigate the properties of mixed stars formed by hadronic and quark matter in $\beta$-equilibrium described by appropriate equations of state (EOS) in the framework of relativistic mean-field theory. We use the non- linear Walecka model for the hadron matter and the MIT Bag and the Nambu-Jona-Lasinio models for the quark matter. The phase transition to a deconfined quark phase is investigated. In particular, we study the dependence of the onset of a mixed phase and a pure quark phase on the hyperon couplings, quark model and properties of the hadronic model. We calculate the strangeness fraction with baryonic density for the different EOS. With the NJL model the strangeness content in the mixed phase decreases. The calculations were performed for T=0 and for finite temperatures in order to describe neutron and proto-neutron stars. The star properties are discussed. Both the Bag model and the NJL model predict a mixed phase in the interior of the star. Maximum allowed masses for proto-neutron stars are larger for the NJL model ($\sim 1.9$ M$_{\bigodot}$) than for the Bag model ($\sim 1.6$ M$_{\bigodot}$).Comment: RevTeX,14 figures, accepted to publication in Physical Review