Evolving Social Networks via Friend Recommendations

A social network grows over a period of time with the formation of new connections and relations. In recent years we have witnessed a massive growth of online social networks like Facebook, Twitter etc. So it has become a problem of extreme importance to know the destiny of these networks. Thus predicting the evolution of a social network is a question of extreme importance. A good model for evolution of a social network can help in understanding the properties responsible for the changes occurring in a network structure. In this paper we propose such a model for evolution of social networks. We model the social network as an undirected graph where nodes represent people and edges represent the friendship between them. We define the evolution process as a set of rules which resembles very closely to how a social network grows in real life. We simulate the evolution process and show, how starting from an initial network, a network evolves using this model. We also discuss how our model can be used to model various complex social networks other than online social networks like political networks, various organizations etc..Comment: 5 pages, 8 figures, 2 algorithm

Noise-induced Regime Shifts: A Quantitative Characterization

Diverse complex dynamical systems are known to exhibit abrupt regime shifts at bifurcation points of the saddle-node type. The dynamics of most of these systems, however, have a stochastic component resulting in noise driven regime shifts even if the system is away from the bifurcation points. In this paper, we propose a new quantitative measure, namely, the propensity transition point as an indicator of stochastic regime shifts. The concepts and the methodology are illustrated for the one-variable May model, a well-known model in ecology and the genetic toggle, a two-variable model of a simple genetic circuit. The general applicability and usefulness of the method for the analysis of regime shifts is further demonstrated in the case of the mycobacterial switch to persistence for which experimental data are available.Comment: 10 Pages, 9 figures, revtex4-1, published versio

Water Quality of Two Century old Freshwater Pond of Orai, Jalaun district Bundelkhand Region, U.P., India

 Orai is a city and a municipal board in Jalaun district in the Indian state of Uttar Pradesh. Historical Place in Orai is Mahil Talab (lake) which was constructed by Raja Mahil. Mahil Talab is located in center of the city. The physico chemical characteristic and metal concentrations were studied. Water samples were collected quarterly from ten different sites from Mahil pond during the month of November 2006 to April 2008. In cationic abundance sodium is followed by magnesium, potassium and calcium (Na> Mg > K > Ca) in pond water through out the year. The tolerance limit for TDS, SAR and % Na of water use for irrigation has been found to be fair for TDS with some exception, unsuitable for SAR and unsuitable for % Na. Nitrate, Sulphate and Phosphate were found to below the permissible limit of WHO. The presence of heavy metals followed by Mn>Pb>Fe>C>Zn>Cu>Al>Cd in the pond water throughout the year. Co, Ni and Hg were not detected in any season

A novel synthesis of β-lactam fused cyclic enediynes by intramolecular Kinugasa reaction

A general synthetic route to β-lactam-fused enediynes by intramolecular Kinugasa reaction has been successfully developed. The method has widened the scope of Kinugasa reaction in the synthesis of sensitive systems like the one described in this communication

Environmental Impacts of Mining on Bundelkhand Region of Uttar Pradesh, India

Surface mining creates more pollution in comparison to underground mining. This paper highlights the impact of mining on air, water and human health in and around the mining areas of Jhansi, Bundelkhand region, India. The possibility of leaching contaminants from the ore material kept in the open ground or from the wastages or degraded ore material produced during the mining processes may contaminate the groundwater in the study area. The mining activity comprising drilling, blasting, loading of waste, transport of overburden and crushing of ore is having considerable impacts on the air environment and well being of living organism. Mining either by opencast or by underground methods damages the water regime and thus causes a reduction in the overall availability of water in and around the mining areas. This study showed that the ground water and surface water was alkaline in nature. Mineral handling, mineral preparation and associated activities mainly contribute RSPM and SPM to the surrounding environment. The minimum and maximum value of RSPM and SPM was 173.1 mg m-3 to 212 mg m-3 and 462.4 mg m-3 to 521.3 mg m-3 respectively. High levels of suspended particulate matter increase respiratory diseases such as chronic bronchitis and asthma causing health hazards to the exposed population. Metals like Cd, Mn, Pb, Cu, Fe and Si concentrations were found to the above permissible limit at some places in different seasons and may cause health hazards in existing environment

Soil quality of degraded land of Bundelkhand region with special reference to Jhansi district of Uttar Pradesh

Present study has been taken to assess the quality of soil in and around Jhansi district of Bundelkhand region of Uttar Pradesh which is also known as ecologically fragile ecosystem. For the present investigation fifteen villages have been selected randomly. Majority of the soil in this area has been found in less nutritive value and not suitable for proper agricultural activities. Results show that pH of the soils varies 6.8 to 8.4; OC 0.07 to 0.78%; and N 0.01 to 0.13% respectively. Available P, K as well as micronutrients viz. Cu, Fe, Mn, Zn are also found less than standard as prescribed by Indian Council of Agricultural Research, New Delhi and not in suitable for agricultural crops. ÂÂ

Localizing genuine multiparty entanglement in noisy stabilizer states

Characterizing large noisy multiparty quantum states using genuine multiparty entanglement is a challenging task. In this paper, we calculate lower bounds of genuine multiparty entanglement localized over a chosen multiparty subsystem of multi-qubit stabilizer states in the noiseless and noisy scenario. In the absence of noise, adopting a graph-based technique, we perform the calculation for arbitrary graph states as representatives of the stabilizer states, and show that the graph operations required for the calculation has a polynomial scaling with the system size. As demonstrations, we compute the localized genuine multiparty entanglement over subsystems of large graphs having linear, ladder, and square structures. We also extend the calculation for graph states subjected to single-qubit Markovian or non-Markovian Pauli noise on all qubits, and demonstrate, for a specific lower bound of the localizable genuine multiparty entanglement corresponding to a specific Pauli measurement setup, the existence of a critical noise strength beyond which all of the post measured states are biseparable. The calculation is also useful for arbitrary large stabilizer states under noise due to the local unitary connection between stabilizer states and graph states. We demonstrate this by considering a toric code defined on a square lattice, and computing a lower bound of localizable genuine multiparty entanglement over a non-trivial loop of the code. Similar to the graph states, we show the existence of the critical noise strength in this case also, and discuss its interesting features.Comment: 36 pages, 21 figures, 2 table