Adsorption assisted translocation of a chain molecule through a pore in a spherical vesicle

We analyze the free energy for translocation of a polymer from the outside of a spherical vesicle to the inside. The process is assumed to be driven by the adsorption of the polymer on the inner surface of the vesicle. We argue that in the case where the polymer is adsorbed on the outer surface too, the entropic barrier for translocation is absent. We analyze the adsorption energy and find the free energy profile for the process. We argue that the motion corresponds to a polymer crossing a region with a change in free energy per segment. Based upon our earlier analsis of the behaviour of kinks in such a problem, we conclude that the translocation can occur with a crossing time $t_{cross}\sim N$

Delay Optimal Event Detection on Ad Hoc Wireless Sensor Networks

We consider a small extent sensor network for event detection, in which nodes take samples periodically and then contend over a {\em random access network} to transmit their measurement packets to the fusion center. We consider two procedures at the fusion center to process the measurements. The Bayesian setting is assumed; i.e., the fusion center has a prior distribution on the change time. In the first procedure, the decision algorithm at the fusion center is \emph{network-oblivious} and makes a decision only when a complete vector of measurements taken at a sampling instant is available. In the second procedure, the decision algorithm at the fusion center is \emph{network-aware} and processes measurements as they arrive, but in a time causal order. In this case, the decision statistic depends on the network delays as well, whereas in the network-oblivious case, the decision statistic does not depend on the network delays. This yields a Bayesian change detection problem with a tradeoff between the random network delay and the decision delay; a higher sampling rate reduces the decision delay but increases the random access delay. Under periodic sampling, in the network--oblivious case, the structure of the optimal stopping rule is the same as that without the network, and the optimal change detection delay decouples into the network delay and the optimal decision delay without the network. In the network--aware case, the optimal stopping problem is analysed as a partially observable Markov decision process, in which the states of the queues and delays in the network need to be maintained. A sufficient statistic for decision is found to be the network-state and the posterior probability of change having occurred given the measurements received and the state of the network. The optimal regimes are studied using simulation.Comment: To appear in ACM Transactions on Sensor Networks. A part of this work was presented in IEEE SECON 2006, and Allerton 201

Contract Farming: Problems, Prospects and its Effect on Income and Employment

This farm-level study conducted in the Tumkur district of Karnataka state has reported the effect of contract farming on income and employment generation and has identified constraints in and prospects of contract farming. Both income and employment generation have been found higher, almost double, on contract than non-contract farms. The study has observed dominance of female labour on both types of farms. Delayed payment for crop produce, lack of credit for crop production, scarcity of water for irrigation, erratic power supply and difficulty in meeting quality requirements have been found to be the major constraints faced by contract farmers. The scarcity of water for irrigation, erratic power supply, lack of credit for crop production, and lower price for crop produce have been identified as major constraints of non-contract farmers. The major constraints expressed by the contracting agencies in expanding contract farming include violation of terms and conditions by farmers, lack of proper management by the company, frequent price fluctuations in international markets, and scarcity of transport vehicles during peak periods.Farm Management,

Elliptical flow and isospin effects in heavy-ion collisions at intermediate energies

The elliptical flow of fragments is studied for different systems at incident energies between 50 and 1000 MeV/nucleon using the isospin-dependent quantum molecular dynamics (IQMD) model. Our findings reveal that elliptical flow shows a transition from positive (in-plane) to negative (out-of-plane) values in the midrapidity region at a certain incident energy known as the transition energy. This transition energy is found to depend on the model ingredients, size of the fragments, and composite mass of the reacting system as well as on the impact parameter of the reaction. A reasonable agreement is observed for the excitation function of elliptical flow between the data and our calculations. Interestingly, the transition energy is found to exhibit a power-law mass dependence.Comment: 16 pages, 8 figure