A Network Flow Model for Irrigation Water Management

Irrigation water management plays a crucial role in the growth and prosperity of countries like India. Optimization Techniques can be effectively used in the management of irrigation water. Motivated by a real crisis in Andhra Pradesh, India, the authors made an attempt to provide scientific solution to the problem of management of Pennar Delta System of Nellore District in Andhra Pradesh. The problem concerns the management of water distribution and scheduling for given requirements and availabilities of water at various nodes of the irrigation network of the system. This article provides a model and framework for the problem in question. The problem is formulated as a dynamic minimum cost network flow problem and provides an approach to solve the problem using static network flow models. A need based software is also developed to solve the network flow problems. Some issues in the programming are discussed

Use of epoxysepharose for protein immobilisation

Epoxy Sepharose, an activated affinity matrix which has been used for immobilisation of carbohydrates has been tried for immobilisation of proteins. Under normal conditions of coupling at neutral or alkaline pH proteins do not couple to epoxy Sepharose. However, a very high salt concentration during coupling allows the binding of proteins to epoxy Sepharose at a pH as low as 8.5. Increasing ionic strength and/or pH facilitates the binding. The bioactivity of the proteins is not destroyed by the immobilisation. This matrix, unlike cyanogen bromide-Sepharose, retains its ability to bind albumin by 80-90% even after 60 days of storage in aqueous suspension at 4°C. Its capacity to bind proteins is comparable to that of cyanogen bromide-Sepharose

Spin-excitations of the quantum Hall ferromagnet of composite fermions

The spin-excitations of a fractional quantum Hall system are evaluated within a bosonization approach. In a first step, we generalize Murthy and Shankar's Hamiltonian theory of the fractional quantum Hall effect to the case of composite fermions with an extra discrete degree of freedom. Here, we mainly investigate the spin degrees of freedom, but the proposed formalism may be useful also in the study of bilayer quantum-Hall systems, where the layer index may formally be treated as an isospin. In a second step, we apply a bosonization scheme, recently developed for the study of the two-dimensional electron gas, to the interacting composite-fermion Hamiltonian. The dispersion of the bosons, which represent quasiparticle-quasihole excitations, is analytically evaluated for fractional quantum Hall systems at \nu = 1/3 and \nu = 1/5. The finite width of the two-dimensional electron gas is also taken into account explicitly. In addition, we consider the interacting bosonic model and calculate the lowest-energy state for two bosons. Besides a continuum describing scattering states, we find a bound-state of two bosons. This state is interpreted as a pair excitation, which consists of a skyrmion of composite fermions and an antiskyrmion of composite fermions. The dispersion relation of the two-boson state is evaluated for \nu = 1/3 and \nu = 1/5. Finally, we show that our theory provides the microscopic basis for a phenomenological non-linear sigma-model for studying the skyrmion of composite fermions.Comment: Revised version, 14 pages, 4 figures, accepted to Phys. Rev.

Room temperature soft ferromagnetism in the nanocrystalline form of YCo2 - a well-known bulk Pauli paramagnet

The Laves phase compound, YCo2, is a well-known exchange-enahnced Pauli paramagnet. We report here that, in the nanocrystalline form, this compound interestingly is an itinerant ferromagnet at room temperature with a low coercive-field. The magnitude of the saturation moment (about 1 Bohr-magneton per formula unit) is large enough to infer that the ferromagnetism is not a surface phenomenon in these nanocrystallites. Since these ferromagnetic nanocrystallines are easy to synthesize with a stable form in air, one can explore applications, particularly where hysteresis is a disadvantage

Hybrid Compressed Sensing and Secure Fault Tolerant Data Aggregation in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) commonly comprise numerous low-cost sensor nodes that possess limited sensing, computation, and communication capabilities. Given the constrained resources of these sensor nodes, it becomes crucial to minimize data transmission to enhance both the average sensor lifetime and overall bandwidth utilization. Data aggregation serves as a process of summarizing and merging sensor data to reduce the volume of data transmitted within the network. Since wireless sensor networks are typically deployed in remote and challenging environments for transmitting sensitive information, sensor nodes are vulnerable to node compromise attacks. Consequently, security issues such as data confidentiality and integrity assume paramount importance. Therefore, when designing wireless sensor network protocols, such as data aggregation protocols, it is imperative to prioritize security and energy efficiency. In this work, we focus on these issues and develop a novel data aggregation approach by using a compressed sensing mechanism. The proposed approach is Hybrid Compressed sensing Secure Fault Tolerant Data Aggregation (HCSFTDA). Moreover, we focus on incorporating security therefore we present a novel mechanism for key distribution and data integrity verification. The performance of the HCSFTDA approach is measured in terms of packet delivery rate, average energy consumption and overhead and compared with existing approaches. The comparative analysis shows that the HCSFTDA achieved better performance. The experimental analysis shows that the proposed model reported average energy consumption as 0.0667, packet delivery as 98% and reduced communication overhead as 400 Kbps

In vitro measurement of nucleus pulposus swelling pressure: A new technique for studies of spinal adaptation to gravity

Swelling of the intervertebral disc nucleus pulposus is altered by posture and gravity. We have designed and tested a new osmometer for in vitro determination of nucleus pulposus swelling pressure. The functional principle of the osmometer involves compressing a sample of nucleus pulposus with nitrogen gas until saline pressure gradients across a 0.45 microns Millipore filter are eliminated. Swelling pressure of both pooled dog and pooled pig lumbar disc nucleus pulposus were measured on the new osmometer and compared to swelling pressures determined using the equilibrium dialysis technique. The osmometer measured swelling pressures comparable to those obtained by the dialysis technique. This osmometer provides a rapid, direct, and accurate measurement of swelling pressure of the nucleus pulposus

Radioimmunoassay of polypeptide hormones using immunochemically coated plastic tubes

A method has been developed for immobilisation of antisera on fresh plastic tubes through an immunochemical bridge. This type of immobilisation has been shown to be more consistent than direct adsorption on plastic. Such immunochemically coated antisera on plastic tube has been used in the development of a noncentrifugation radioimmunoassay. This assay system has been found to be technically as sound as the conventional method

Finite Temperature Magnetism in Fractional Quantum Hall Systems: Composite Fermion Hartree-Fock and Beyond

Using the Hamiltonian formulation of Composite Fermions developed recently, the temperature dependence of the spin polarization is computed for the translationally invariant fractional quantum Hall states at $\nu=1/3$ and $\nu=2/5$ in two steps. In the first step, the effect of particle-hole excitations on the spin polarization is computed in a Composite Fermion Hartree-Fock approximation. The computed magnetization for $\nu=1/3$ lies above the experimental results for intermediate temperatures indicating the importance of long wavelength spin fluctuations which are not correctly treated in Hartree-Fock. In the second step, spin fluctuations beyond Hartree-Fock are included for $\nu=1/3$ by mapping the problem on to the coarse-grained continuum quantum ferromagnet. The parameters of the effective continuum quantum ferromagnet description are extracted from the preceding Hartree-Fock analysis. After the inclusion of spin fluctuations in a large-N approach, the results for the finite-temperature spin polarization are in quite good agreement with the experiments.Comment: 10 pages, 8 eps figures. Two references adde

A solid phase radioimmunoassay for detection of early pregnancy in the South Indian bonnet monkey Macaca radiata

Using an antibody raised in the rabbit to ovine leutenizing hormone β subunit coupled to activated cellulose, a solid phase radioimmunoassay to detect early pregnancy in the South Indian bonnet monkey has been developed. Non-specific inhibition due to serum was eliminated by inclusion of new born calf serum in the assay tubes. The assay is simple, needs only one centrifugation and can be completed in 6 h at room temperature with no false positive results