Causes and Impact of Labour Migration: A Case Study of Punjab Agriculture

In Punjab, the influx of migrant labour particularly in agriculture sector started with the green revolution and picked up subsequently. Due to monoculture in the cropping pattern, the state has become largely dependent on migrant labourers for various agricultural operations. The influx of seasonal as well as permanent labour from outside has led to various socio-economic problems in Punjab. In the wake of this, the present study was purposively conducted in the Central Zone of Punjab for the year 2011 to find the causes and impact of labour in-migration in Punjab. A total of 105 respondents belonging to the states of Bihar, Uttar Pradesh, Jharkhand, Madhya Pradesh and Nepal constituted the sample frame. The results have revealed that better income and employment opportunities at the destination place were the major factors responsible for migration. About 64 per cent of the respondents earned less than ` 20000 per annum at their native places and 60 per cent of them had less than 200 days of employment in a year, whereas 23 per cent of the labourers were unemployed at their native place. However, after migration 63 per cent of the migrants could earn from ` 20000 to ` 50000 per annum and 34 per cent earned more than ` 50000 per annum in Punjab, leading to a major share (60% of total income) as remittances sent back to their native places. On the other hand, the flip side of the influx of migrants in the study area increased the drug menace by 37 per cent, social tension by 45 per cent and crime by 43 per cent. The state government should maintain a demographic balance by regulating the migrants and should help in verification of credentials of migrating labourers to Punjab.Labour migration, Long-term migration, Short-term migration, Remittances, In-migration, Agricultural and Food Policy, J61, J62, R23,

Marketing Efficiency of Green Peas under Different Supply Chains in Punjab

During the year 2007-08, the area under green peas in Punjab was 18.45 thousand hectares with a production of 1.11 lakh tonnes. The total consumption at the farm level being just 2.54 per cent, the marketed surplus was 97.46 per cent. The maximum quantity of green peas was sold by the growers in the wholesale market (about 89%) and the rest was sold at the farm, in the village and in Apni Mandi. The marketing of green peas has been studied by three supply chains, viz. I: Producer → wholesaler (through commission agent) → retailer → consumer; II: Producer → retailer (through commission agent) → consumer; III: Producer → consumer. The net price received by the producer was 67 per cent, 69 per cent and 94 per cent in supply chains I, II and III respectively in the Hoshiarpur market in January, 2009. The producer’s share in supply chain III was the maximum because of direct sale by the producer to the consumer. The supply chain III has been found most efficient because its marketing efficiency was 14.83 as compared to 2.70 in supply chain II and 2.38 in supply chain I. The low marketing efficiency in supply chain I was on account of a higher number of market intermediaries in this chain. The functional analysis of the factors affecting the marketing efficiency has revealed that with one per cent increase in marketing margins and costs, the marketing efficiency declined by 0.45 per cent and 0.44 per cent, respectively. The modern market infrastructure may be built up with the public-private partnership to bring efficiency in the marketing of green peas.Marketing efficiency, Green peas, Supply chains, Punjab, Price spread, Agricultural and Food Policy, Q13, Q12,

Theoretical search for Chevrel phase based thermoelectric materials

We investigate the thermoelectric properties of some semiconducting Chevrel phases. Band structure calculations are used to compute thermopowers and to estimate of the effects of alloying and disorder on carrier mobility. Alloying on the Mo site with transition metals like Re, Ru or Tc to reach a semiconducting composition causes large changes in the electronic structure at the Fermi level. Such alloys are expected to have low carrier mobilities. Filling with transition metals was also found to be incompatible with high thermoelectric performance based on the calculated electronic structures. Filling with Zn, Cu, and especially with Li was found to be favorable. The calculated electronic structures of these filled Chevrel phases are consistent with low scattering of carriers by defects associated with the filling. We expect good mobility and high thermopower in materials with the composition close to (Li,Cu)$_4$Mo$_6$Se$_8$, particularly when Li-rich, and recommend this system for experimental investigation.Comment: 4 two-column pages, 4 embedded ps figure

Superconductivity and Electronic Structure of Perovskite MgCNi3

The electronic structure, stability, electron phonon coupling and superconductivity of the non-oxide perovskite MgCNi$_3$ are studied using density functional calculations. The band structure is dominated by a Ni $d$ derived density of states peak just below the Fermi energy, which leads to a moderate Stoner enhancement, placing MgCNi$_3$ in the range where spin fluctuations may noticeably affect transport, specific heat and superconductivity, providing a mechanism for reconciling various measures of the coupling $\lambda$. Strong electron phonon interactions are found for the octahedral rotation mode and may exist for other bond angle bending modes. The Fermi surface contains nearly cancelling hole and electron sheets that give unusual behavior of transport quantities particularly the thermopower. The results are discussed in relation to the superconductivity of MgCNi$_3$.Comment: 4 pages, RevTex, 5 ps figure

Structural phase control of (La1.48_{1.48}Nd0.40_{0.40}Sr0.12_{0.12})CuO4_4 thin films by epitaxial growth technique

Epitaxial growth of (La$_{1.48}$Nd$_{0.40}$Sr$_{0.12}$)CuO$_4$ thin films was studied by pulsed-laser deposition technique on three different substrates, SrTiO$_3$ (100), LaSrAlO$_4$ (001), and YAlO$_3$ (001). The (Nd,Sr,Ce)$_2$CuO$_4$-type structure appears at the initial growth stage on SrTiO$_3$ (100) when the film is deposited under the growth conditions optimized for (La,Sr)$_2$CuO$_4$. This (Nd,Sr,Ce)$_2$CuO$_4$-type structure can be eliminated by increasing the substrate temperature and the laser repetition frequency. Films on LaSrAlO$_4$ (001) maintain a La$_2$CuO$_4$-type structure as bulk samples, but those on YAlO$_3$ (001) show phase separation into La$_2$CuO$_4$- and Nd$_2$CuO$_4$-type structures. Such complicated results are explained in terms of the competition between lattice misfit and thermodynamic conditions. Interestingly the films with La$_2$CuO$_4$-type structure prepared on SrTiO$_3$ and LaSrAlO$_4$ show different surface structures and transport properties. The results indicate the possibility of controlling charge stripes of (La$_{1.48}$Nd$_{0.40}$Sr$_{0.12}$)CuO$_4$ as was demonstrated in (La,Ba)$_2$CuO$_4$ thin films by Sato et al. (Phys. Rev. B {\bf 62}, R799 (2000)).Comment: 5 pages, 6 EPS figure, accepted for publication in Phys. Rev.

Penrose limits of Lie Branes and a Nappi--Witten braneworld

Departing from the observation that the Penrose limit of AdS_3 x S^3 is a group contraction in the sense of Inonu and Wigner, we explore the relation between the symmetric D-branes of AdS_3 x S^3 and those of its Penrose limit, a six-dimensional symmetric plane wave analogous to the four-dimensional Nappi--Witten spacetime. Both backgrounds are Lie groups admitting bi-invariant lorentzian metrics and symmetric D-branes wrap their (twisted) conjugacy classes. We determine the (twisted and untwisted) symmetric D-branes in the plane wave background and we prove the existence of a space-filling D5-brane and, separately, of a foliation by D3-branes with the geometry of the Nappi--Witten spacetime which can be understood as the Penrose limit of the AdS_2 x S^2 D3-brane in AdS_3 x S^3. Parenthetically we also derive a simple criterion for a symmetric plane wave to be isometric to a lorentzian Lie group. In particular we observe that the maximally supersymmetric plane wave in IIB string theory is isometric to a lorentzian Lie group, whereas the one in M-theory is not.Comment: 21 pages (v2: references added

Projected SO(5) Hamiltonian for Cuprates and Its Applications

The projected SO(5) (pSO(5)) Hamiltonian incorporates the quantum spin and superconducting fluctuations of underdoped cuprates in terms of four bosons moving on a coarse grained lattice. A simple mean field approximation can explain some key feautures of the experimental phase diagram: (i) The Mott transition between antiferromagnet and superconductor, (ii) The increase of T_c and superfluid stiffness with hole concentration x and (iii) The increase of antiferromagnetic resonance energy as sqrt{x-x_c} in the superconducting phase. We apply this theory to explain the ``two gaps'' problem found in underdoped cuprate Superconductor-Normal- Superconductor junctions. In particular we explain the sharp subgap Andreev peaks of the differential resistance, as signatures of the antiferromagnetic resonance (the magnon mass gap). A critical test of this theory is proposed. The tunneling charge, as measured by shot noise, should change by increments of Delta Q= 2e at the Andreev peaks, rather than by Delta Q=e as in conventional superconductors.Comment: 3 EPS figure