Discrimination in an elite labour market? Job placements at the Indian Institute of Management, Ahmedabad

Using data on the IIM-Ahmedabad's 2006 batch of MBA graduates, we find that SC/ST (Scheduled Caste or Scheduled Tribe) graduates get significantly lower wages (between 19 and 35 percent depending on the exchange rate used to convert foreign currencies) than those in the general category. This difference disappears once the lower GPAs (Grade Point Averages) of SC/ST candidates are accounted for, suggesting that the large wage difference is due to the weaker (on average) academic performance of SC/ST candidates. Controlling for work experience and GPA, there is no wage penalty to being female. Moreover, unlike the case in US and British labour markets, there is only weak evidence of wage premium to being more attractive, where attractiveness was measured in the standard manner by anonymous ratings of passport-type photographs by twenty raters. The study suggests that in the absence of any serious attempt to equalise school-level opportunities, the current policy of reservations at elite educational institutions will be insufficient to equalise career outcomes even for the minority of SC/ST candidates that can benefit from them.

Incentives for Developers’ Contributions and Product Performance Metrics in Open Source Development: An Empirical Exploration

In open source software development, users rather than paid developers engage in innovation and development without the direct involvement of manufacturers. This paradigm cannot be explained by the two traditional models of innovation, the private investment model and the collective action model. Neither model in itself can explain the phenomenon of the open source model or its success. In order to bridge the gap between existing models and the open source phenomenon, we analyze data from a web survey of 160 open source developers. First, we investigate the motives affecting the individual developer’s contributions by comparing and contrasting the incentives from both the traditional private investment and collective action models. Second, we demonstrate that there is a common ground between the private and collective models where private returns and social considerations can coexist. Third, we explore the effect of incentives on the output of innovation—final product performance. The results show that the motivations for individual developer’s contributions are quite different from the incentives that affect product performance.

Topological density wave states of non-zero angular momentum

The pseudogap state of high temperature superconductors is a profound mystery. It has tantalizing evidence of a number of broken symmetry states, not necessarily conventional charge and spin density waves. Here we explore a class of more exotic density wave states characterized by topological properties observed in recently discovered topological insulators. We suggest that these rich topological density wave states deserve closer attention in not only high temperature superconductors but in other correlated electron states, as in heavy fermions.Comment: Expanded version, 7 pages, 6 figure

Classification of the line-soliton solutions of KPII

In the previous papers (notably, Y. Kodama, J. Phys. A 37, 11169-11190 (2004), and G. Biondini and S. Chakravarty, J. Math. Phys. 47 033514 (2006)), we found a large variety of line-soliton solutions of the Kadomtsev-Petviashvili II (KPII) equation. The line-soliton solutions are solitary waves which decay exponentially in $(x,y)$-plane except along certain rays. In this paper, we show that those solutions are classified by asymptotic information of the solution as $|y| \to \infty$. Our study then unravels some interesting relations between the line-soliton classification scheme and classical results in the theory of permutations.Comment: 30 page

Quantum Hall plateau transition in the lowest Landau level of disordered graphene

We investigate, analytically and numerically, the effects of disorder on the density of states and on the localization properties of the relativistic two dimensional fermions in the lowest Landau level. Employing a supersymmetric technique, we calculate the exact density of states for the Cauchy (Lorentzian) distribution for various types of disorders. We use a numerical technique to establish the localization-delocalization (LD) transition in the lowest Landau level. For some types of disorder the LD transition is shown to belong to a different universality class, as compared to the corresponding nonrelativistic problem. The results are relevant to the integer quantum Hall plateau transitions observed in graphene.Comment: 18 pages and 11 figure

Universal Magnetic Properties of La2−δSrδCuO4La_{2-\delta} Sr_{\delta} Cu O_4 at Intermediate Temperatures

We present the theory of two-dimensional, clean quantum antiferromagnets with a small, positive, zero temperature ($T$) stiffness $\rho_s$, but with the ratio $k_B T / \rho_s$ arbitrary. Universal scaling forms for the uniform susceptibility ($\chi_u$), correlation length($\xi$), and NMR relaxation rate ($1/T_1$) are proposed and computed in a $1/N$ expansion and by Mont\'{e}-Carlo simulations. For large $k_B T/\rho_s$, $\chi_u (T)/T$ and $T\xi(T)$ asymptote to universal values, while $1/T_{1}(T)$ is nearly $T$-independent. We find good quantitative agreement with experiments and some numerical studies on $La_{2-\delta} Sr_{\delta} Cu O_4$.Comment: 14 pages, REVTEX, 1 postscript figure appende

Theory of d-density wave viewed from a vertex model and its implications

The thermal disordering of the $d$-density wave, proposed to be the origin of the pseudogap state of high temperature superconductors, is suggested to be the same as that of the statistical mechanical model known as the 6-vertex model. The low temperature phase consists of a staggered order parameter of circulating currents, while the disordered high temperature phase is a power-law phase with no order. A special feature of this transition is the complete lack of an observable specific heat anomaly at the transition. There is also a transition at a even higher temperature at which the magnitude of the order parameter collapses. These results are due to classical thermal fluctuations and are entirely unrelated to a quantum critical point in the ground state. The quantum mechanical ground state can be explored by incorporating processes that causes transitions between the vertices, allowing us to discuss quantum phase transition in the ground state as well as the effect of quantum criticality at a finite temperature as distinct from the power-law fluctuations in the classical regime. A generalization of the model on a triangular lattice that leads to a 20-vertex model may shed light on the Wigner glass picture of the metal-insulator transition in two-dimensional electron gas. The power-law ordered high temperature phase may be generic to a class of constrained systems and its relation to recent advances in the quantum dimer models is noted.Comment: RevTex4, 10 pages, 11 figure

Golden geese or white elephants? The paradoxes of world heritage sites and community-based tourism development in Agra, India

This study examines the relationship between World Heritage Sites (WHSs) and local community development in Agra, India. We investigate two interrelated themes: the role of planning in developing the tourism potential of the Taj Mahal and other WHSs in Agra, and the impact of the WHS framework on the development of the city. We analyze the weaknesses of the institutions and agencies responsible for Agra's inability to convert the development potential created by its three WHSs into significant economic, community and infrastructure improvements. The Agra case reveals a set of developmental paradoxes, whereby the restructuring of the tourist industry induced by the designation of WHSs does not lead to proportionate advances in local community development. Several factors were found to be systemic problems, but some recent schemes are worth supporting and expanding. The paradoxes and potential of economic, tourism, and community development in Agra echo those of other developing localities which host WHSs around the world. Following an assessment of problems and challenges, a set of recommendations is directed toward the development of pro-poor, community-based heritage tourism with the aim of informing integrated planning for the community and for heritage and tourism resources in the future

Correlation Lengths in Quantum Spin Ladders

Analytic expressions for the correlation length temperature dependences are given for antiferromagnetic spin-1/2 Heisenberg ladders using a finite-size non-linear sigma-model approach. These calculations rely on identifying three successive crossover regimes as a function of temperature. In each of these regimes, precise and controlled approximations are formulated. The analytical results are found to be in excellent agreement with Monte Carlo simulations for the Heisenberg Hamiltonian.Comment: 5 pages LaTeX using RevTeX, 3 encapsulated postscript figure

Fly-by-light flight control system technology development plan

The results of a four-month, phased effort to develop a Fly-by-Light Technology Development Plan are documented. The technical shortfalls for each phase were identified and a development plan to bridge the technical gap was developed. The production configuration was defined for a 757-type airplane, but it is suggested that the demonstration flight be conducted on the NASA Transport Systems Research Vehicle. The modifications required and verification and validation issues are delineated in this report. A detailed schedule for the phased introduction of fly-by-light system components has been generated. It is concluded that a fiber-optics program would contribute significantly toward developing the required state of readiness that will make a fly-by-light control system not only cost effective but reliable without mitigating the weight and high-energy radio frequency related benefits