Impact of Land Tenure System in Watershed Development Programmes in the Meghalaya State, North-East India

Besides the analysis of technical and ecological viability, knowledge of the existing land tenure systems is an essential pre-requisite for the success of watershed projects and policy reforms required for their effective implementation. Using descriptive analysis, Lorenz curve and Gini concentration ratio (GCR), this study has explained the relationship between the existing land tenure systems and the prospects for the success of watershed projects in the Meghalaya State, North-East India. The study has revealed that the Umsiang watershed project having community ownership system of tenure produced more positive changes in the landuse pattern after the project implementation than the Maweit watershed project practising individual ownership system. The area under jhum cultivation in the Umsiang watershed decreased significantly due to transformation of jhum sloppy lands into permanent contour cultivation. The area under horticulture plantations particularly fruit crops increased by 2118 per cent; afforested and aquaculture areas also increased by 296 and 2480 per cent, respectively after the project. The area under jhum cultivation in the Maweit watershed decreased only marginally (by 2%) and the area under permanent contour cultivation was negligible after the project. The absence of ownership rights to the tenants in the Maweit watershed has resulted in little incentive for the adoption of long-term development measures. The annual average income per household increased to Rs 40,227 (36% increase) in the Umsiang watershed and to Rs 36,313 (19% increase) in the Maweit watershed after the project. The offfarm income went up by 49 per cent in the Umsiang watershed and 38 per cent in the Maweit watershed. The watershed projects under the Community ownership system of land tenure would be more successful in increasing farm income and employment opportunities. The income inequality also decreased in the Umsiang watershed after the project as shown by Lorenz curve and GCR. But the gap between the rich and the poor in the Maweit watershed increased after the project. The study has clearly indicated that land tenure system is an important factor in the implementation of watershed projects successfully. Effective land reform policy would be essential for the successful implementation of watershed development programmes.Agricultural and Food Policy,

Experimental study of the erosion of Ar/H2 plasma facing carbon surfaces: optical emission spectroscopy, mass spectrometry and spectroscopic ellipsometry measurements

Carbon materials could be used for divertor plates in the ITER fusion device. Numerous studies (experimental or modeling) have been undertaken to better understand the chemical processes involved in carbon erosion by hydrogen atoms or ions. These works have been performed for several kinds of carbon layers and different hydrogen (or deuterium) ion fluxes. Results of an experimental study on carbon-material erosion under hydrogen bombardment will be presented. Optical emission spectroscopy and mass spectrometry have been employed to determine the presence of excited and stable molecules that are formed under these conditions. Ex situ spectroscopic ellipsometry has been used to calculate the erosion rate. In order to determine this erosion rate during plasma exposure and with a better precision, preliminary results on in situ spectroscopic ellipsometry will be presented

Trajectory and stability of Lagrangian point L2L_2 in the Sun-Earth system

This paper describes design of the trajectory and analysis of the stability of collinear point $L_2$ in the Sun-Earth system. The modified restricted three body problem with additional gravitational potential from the belt is used as the model for the Sun-Earth system. The effect of radiation pressure of the Sun and oblate shape of the Earth are considered. The point $L_2$ is asymptotically stable upto a specific value of time $t$ correspond to each set of values of parameters and initial conditions. The results obtained from this study would be applicable to locate a satellite, a telescope or a space station around the point $L_2$.Comment: Accepted for publication in Astrophysics & Space Scienc

An ARPES view on the high-Tc problem: phonons vs spin-fluctuations

We review the search for a mediator of high-Tc superconductivity focusing on ARPES experiment. In case of HTSC cuprates, we summarize and discuss a consistent view of electronic interactions that provides natural explanation of both the origin of the pseudogap state and the mechanism for high temperature superconductivity. Within this scenario, the spin-fluctuations play a decisive role in formation of the fermionic excitation spectrum in the normal state and are sufficient to explain the high transition temperatures to the superconducting state while the pseudogap phenomenon is a consequence of a Peierls-type intrinsic instability of electronic system to formation of an incommensurate density wave. On the other hand, a similar analysis being applied to the iron pnictides reveals especially strong electron-phonon coupling that suggests important role of phonons for high-Tc superconductivity in pnictides.Comment: A summary of the ARPES part of the Research Unit FOR538, http://for538.wmi.badw.d

Destruction of diagonal and off-diagonal long range order by disorder in two-dimensional hard core boson systems

We use quantum Monte Carlo simulations to study the effect of disorder, in the form of a disordered chemical potential, on the phase diagram of the hard core bosonic Hubbard model in two dimensions. We find numerical evidence that in two dimensions, no matter how weak the disorder, it will always destroy the long range density wave order (checkerboard solid) present at half filling and strong nearest neighbor repulsion and replace it with a bose glass phase. We study the properties of this glassy phase including the superfluid density, energy gaps and the full Green's function. We also study the possibility of other localized phases at weak nearest neighbor repulsion, i.e. Anderson localization. We find that such a phase does not truly exist: The disorder must exceed a threshold before the bosons (at weak nn repulsion) are localized. The phase diagram for hard core bosons with disorder cannot be obtained easily from the soft core phase diagram discussed in the literature.Comment: 7 pages, 10 eps figures include

How Should Diverse Stakeholder Interests Shape Evaluations of Complex Water Resources Systems Robustness When Confronting Deeply Uncertain Changes?

Robustness analysis can support the design and operation of large-scale water infrastructure projects confronting deeply uncertain futures. However, diverse actors, contextual specificities, sectoral interests, and risk attitudes make it difficult to identify an appropriate robustness metric to rank decision alternatives under deep uncertainty. Here, we clarify how methodological choices affect robustness evaluation using the multi-actor, multi-sector Inchampalli-Nagarjuna Sagar water transfer megaproject in Southern India. We compare a suite of water transfer strategies discovered using evolutionary multi-objective direct policy search (EMODPS), a strategy proposed by regional authorities and the status quo of no water transfer. We stress-test these strategies across scenarios that capture climatic and socioeconomic uncertainties and rank them using robustness metrics representing sectoral perspectives and priorities of different actors with varying risk attitudes. Results show a considerable impact of metric choices on robustness rankings of strategies, with compromise solution discovered via EMODPS as robust. The no-transfer strategy results in the worst water supply robustness with an average volumetric deficit of 17% of total historical demands but emerges as a robust alternative for 6 out of 12 combinations of actor-sectors with high risk aversion. Also, changes in the amplitude of the Indian Summer Monsoon is identified as the most important uncertain factor determining the failure of strategies. Our findings highlight that the selection of robust solutions should be guided by an understanding of how assumed risk attitudes shape stakeholders' perceptions of vulnerabilities. These findings are generalizable to large infrastructure projects with diverse stakeholders and multisectoral impacts

Comparison of superconductivity in Sr_2RuO_4 and copper oxides

To compare the superconductivity in strongly correlated electron systems with the antiferromagnetic fluctuations in the copper oxides and with the ferromagnetic fluctuations in Sr_2RuO_4 a t-J-I model is proposed. The antiferromagnetic coupling J results in the superconducting state of d_{x^2-y^2} symmetry and the ferromagnetic coupling constant I results in the spin-triplet p-type state. The difference in the gap anisotropies provides the large difference in T_c values, for the typical values of the coupling constants: T_c of order of 1K for the ruthenate and T_c of order of 100K for the cuprates.Comment: 4 pages, RevTEX, 3 figs. Submitted to Phys. Rev. Let

Searching for the Slater Transition in the Pyrochlore Cd2_{2}Os2_{2}O7_{7} with Infrared Spectroscopy

Infrared reflectance measurements were made on the single crystal pyrochlore Cd$_{2}$Os$_{2}$O$_{7}$ in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal insulator transition at $T_{MIT}=226K$. All predicted IR active phonons are observed in the conductivity over all temperatures and the oscillator strength is found to be temperature independent. These results indicate that charge ordering plays only a minor role in the MIT and that the transition is strictly electronic in nature. The conductivity shows the clear opening of a gap with $2\Delta=5.2k_{B}T_{MIT}$. The gap opens continuously, with a temperature dependence similar to that of BCS superconductors, and the gap edge having a distinct $\sigma(\omega)\thicksim\omega^{1/2}$ dependence. All of these observables support the suggestion of a Slater transition in Cd$_{2}$Os$_{2}$O$_{7}$.Comment: 4 pages, 4 figure

First-principles Calculation of the Formation Energy in MgO-CaO Solid Solutions

The electronic structure and total energy were calculated for ordered and disordered MgO-CaO solid solutions within the multiple scattering theory in real space and the local density approximation. Based on the dependence of the total energy on the unit cell volume the equilibrium lattice parameter and formation energy were determined for different solution compositions. The formation energy of the solid solutions is found to be positive that is in agreement with the experimental phase diagram, which shows a miscibility gap.Comment: 11 pages, 3 figure

Effects of metallic spacer in layered superconducting Sr2(Mgy_yTi1−y_{1-y})O3FeAs

The highly two-dimensional superconducting system Sr2(Mg$_y$Ti$_{1-y}$)O3FeAs, recently synthesized in the range of 0.2 < y < 0.5, shows an Mg concentration-dependent $T_c$. Reducing the Mg concentration from y=0.5 leads to a sudden increase in $T_c$, with a maximum $T_c$ ~40 K at y=0.2. Using first principles calculations, the unsynthesized stoichiometric y=0 and the substoichiometric y=0.5 compounds have been investigated. For the 50% Mg-doped phase (y=0.5), Sr2(Mg$_y$Ti$_{1-y}$)O3 layers are completely insulating spacers between FeAs layers, leading to the fermiology such as that found for other Fe pnictides. At y=0, representing a phase with metallic Sr2TiO3 layers, the $\Gamma$-centered Fe-derived Fermi surfaces (FSs) considerably shrink or disappear. Instead, three $\Gamma$-centered Ti FSs appear, and in particular two of them have similar size, like in MgB2. Interestingly, FSs have very low Fermi velocity in large fractions: the lowest being 0.6$\times10^6$ cm/s. Furthermore, our fixed spin moment calculations suggest the possibility of magnetic ordering, with magnetic Ti and nearly nonmagnetic Fe ions. These results indicate a crucial role of Sr2(Mg$_y$Ti$_{1-y}$)O3 layers in this superconductivity.Comment: 7 pages; Proceedings of ICSM-201