Quantum random walk of two photons in separable and entangled state

We discuss quantum random walk of two photons using linear optical elements. We analyze the quantum random walk using photons in a variety of quantum states including entangled states. We find that for photons initially in separable Fock states, the final state is entangled. For polarization entangled photons produced by type II downconverter, we calculate the joint probability of detecting two photons at a given site. We show the remarkable dependence of the two photon detection probability on the quantum nature of the state. In order to understand the quantum random walk, we present exact analytical results for small number of steps like five. We present in details numerical results for a number of cases and supplement the numerical results with asymptotic analytical results

Dynamics of coupled phantom and tachyon fields

In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exist late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the scrutinized couplings cannot alleviate the coincidence problem, however acquire stable late time accelerated solutions. We also discuss coupled tachyon field with inverse square potential assuming linear coupling.Comment: 16 pages, 6 caption figures, 3 Tables, text, figure are added, matches with the published versio

Dynamics of interacting quintessence

In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as $A$ namely, $\alpha \dot{\rho_m}$, $\beta \dot{\rho_{\phi}}$ and $\sigma (\dot{\rho_m}+\dot{\rho_{\phi}})$, and present phase space analysis for three different interacting models. We focus on the attractor solutions that can give rise to late time acceleration with $\Omega_{DE}/\Omega_{DM}$ of order unity in order to alleviate the coincidence problem.Comment: 11 pages, 3 figures, matches with the published versio

Leptonic decay of Heavy-light Mesons in a QCD Potential Model

We study the masses and decay constants of heavy-light flavour mesons D, Ds, B and Bs in a QCD Potential model. The mesonic wavefunction is used to compute the masses of D and B mesons in the ground state and the wavefunction is transformed to momentum space to estimate the pseudoscalar decay constants of these mesons. The leptonic decay widths and branching ratio of these mesons for different leptonic channels are also computed to compare with the experimental values. The results are found to be compatible with available data.Comment: 9 pages,3 table

Antifungals, arthropods and antifungal resistance prevention: lessons from ecological interactions

Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods' armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu

A Novel Tractor Operated Grass Seed Harvester Developed in India

The demand of green and dry fodder in India is estimated to increase to 1170 and 650 m tonne whereas availability is expected to be at 411.3 and 488 m tonne in 2025, respectively, depicting deficit of about 64.9% green fodder and 24.9% dry fodder (Vision 2030, ICAR - IGFRI, Jhansi, 2011). In forages, availability of quality seed is only 25-30% in cultivated fodder and less than 10 % in range grasses and legumes (Vision 2050, IGFRI). Prices paid for grass seeds of native species vary from Rs.5,000 to 6,500 per kg for clean, un-haired seeds due to excessive use of manual labour in seed collection and removing hairy portion. In order to increase the capacity of collection of grass seeds from standing crop, A tractor operated grass seed harvester was developed under a collaborative research project of Indian Council of Agricultural Research two Institutes viz. Indian Grassland and Fodder Research Institute and Central Institute of Agricultural Engineering, keeping in view the requirements of common grasses used as feed material in Indian context. This grass seed harvester was made using nylon brushes arranged in specific fashion on a rotating cylinder and a winding reel in front of rotating cylinder to collect grass seed from the grasses standing in the fields, where tractor can operate. The specific features of this machine were variable speed of rotating cylinder brush, helical arrangement of brushes on the cylinder to carry the detached seed in to the seed box, variable height of operation and front mounting of the machine on tractor. This machine was tested for seed collection in Pennisetum pedicellatum (Dinanath grass), Cenchrus cilliaris (Anjan grass ) and Megathyrsus maximum (Guinea grass). Seed collection capacity of the machine was 4.24 to 7.12 kg/h in Dinanath grass during 2nd operation, 2.10 to 3.56 kg/h in Anjan grass and 1.61 to 3.56 kg/h in Guinea grass at the full maturity of the grass seeds in two passes of the machine in to and fro direction. The field capacity of seed collection operation ranged from 0.21 to 0.47 ha/h for the grasses in which it was operated

Earthquake Induced Liquefaction Using Shake Table Test

Loose saturated cohesionless soils may undergo liquefaction due to strong ground motions. Such liquefaction causes significant damage to the structure resting on such soil. The extent of damage primarily depends upon soil properties, intensity of earthquake and type of structure. Various analytical models have been developed to estimate the likelihood of liquefaction of particular site based on field performance. However, if it is possible to identify the sites which are likely to liquefy due to specific intensity of earthquake it will help implementing the reduction in the damage which it would otherwise cause. One such analytical model has been developed by one of the authors of this paper and has been found to satisfactorily demarcate ‘Yes’ and ‘No’ zones of liquefaction for number of earthquakes. However, earlier research shows that laboratory tests could also be conducted to study the liquefaction behavior of soil under specific condition. The present study mainly deals with an attempt made in conducting Shake Table Test in laboratory by simulating earthquake conditions on site. The results obtained from the trial tests have been compared with the actual field cases and also with laboratory tests conducted for such soil by other researchers. It is observed that the criterion of the occurrence of liquefaction in the laboratory model is in close agreement with actual field data. Shake table test is found to be more effective in simulating the strong ground motion during earthquake

Study of Behaviour of Square and Rectangular Footings Resting on Cohesive Soils Based on Model Tests

The estimation of a reliable value of bearing Capacity of soil is the most important step in the foundation design work. Number of theoretical approaches and in-situ tests for the estimation of bearing capacity of footing are available. The reliability of any theory can be demonstrated by comparing the experimental test results on field footings with theoretical predictions. One of the reliable methods is the load test on full sized footing. However, this test as covered under IS 1888-1982 is too expensive and time consuming. Model tests can be conducted on footings of various sizes. The surface characteristics for different loading conditions can provide information on qualitative and quantitative contribution of such parameters on bearing of footings in absence of field test results. It is revealed that research work (Sawant et al (2000), Rajgopal et al (2000), Sawaf et al (2005), Mohmoud et al (1989), Harikrishna et al(2000), Sahu et al (1970) etc.)has been carried out for load tests on model footings resting on sand as foundation medium. However no work has been reported so far on c – Φ soil. In this present study a laboratory model with loading frame has been developed in Geotechnical Engineering Laboratory of College of Engineering, Pune to conduct small scale load tests, to determine Bearing capacity characteristics of footings resting on c-Φ soil. Load tests were conducted on two square, two circular and five rectangular footings resting on c – Φ soil in the laboratory model. The bearing capacity, time – settlement relationship, pressure settlement relationship of footing resting on c – Φ soil and effect of various parameters such as L/B ratio, shape and size of footing on bearing capacity of footing were studied. Comparison is made between bearing capacity of footings estimated by the conventional methods such as Vesic’s, Tezaghi’s method and that estimated by Model Test Results. The model tests provide qualitative information on parameters influencing bearing capacity of footings. These tests can be used to check the bearing capacity estimated by analytical method

Lymphotoxin is an autocrine growth factor for Epstein-Barr virus-infected B cell lines.

Because human lymphotoxin (LT) was originally isolated from a lymphoblastoid cell line, we investigated the role of this molecule in three newly established Epstein-Barr virus (EBV)-infected human B cell lines. These lines were derived from acute lymphoblastic leukemia (Z-6), myelodysplastic syndrome (Z-43), and acute myelogenous leukemia (Z-55) patients who had a prior EBV infection. Each lymphoblastoid cell line had a karyotype that was different from that of the original parent leukemic cells, and all expressed B cell, but not T cell or myeloid surface markers. In all three lines, rearranged immunoglobulin heavy chain joining region (JH) bands were found, and the presence of EBV DNA was confirmed by Southern blotting. Z-6, Z-43, and Z-55 cell lines constitutively produced 192, 48, and 78 U/ml LT, respectively, as assessed by a cytotoxicity assay and antibody neutralization. Levels of tumor necrosis factor (TNF) were undetectable. Scatchard analysis revealed that all the cell lines expressed high-affinity TNF/LT receptors with receptor densities of 4197, 1258, and 1209 sites/cell on Z-6, Z-43, and Z-55, respectively. Furthermore, labeled TNF binding could be reversed by both unlabeled TNF, as well as by LT. Studies with p60 and p80 receptor-specific antibodies revealed that the three lines expressed primarily the p80 form of the TNF receptor. When studied in a clonogenic assay, exogenous LT stimulated proliferation of all three cell lines in a dose-dependent fashion at concentrations ranging from 25 to 500 U/ml. Similar results were obtained with [3H]TdR incorporation. Monoclonal anti-LT neutralizing antibodies at concentrations of 25-500 U/ml inhibited cellular multiplication in a dose-dependent manner. It is interesting that in spite of a common receptor, TNF (1,000 U/ml) had no direct effect on Z-55 cell growth, whereas it partially reversed the stimulatory effect of exogenous LT. In addition, TNF inhibited Z-6 and Z-43 cell proliferation, and its suppressive effect was reversed by exogenous LT. Both p80 and p60 forms of soluble TNF receptors suppressed the lymphoblastoid cell line proliferation and their inhibitory effect was partially reversed by LT. Our data suggest that (a) LT is an autocrine growth factor for EBV-transformed lymphoblastoid B cell lines; and (b) anti-LT antibodies, soluble TNF/LT receptors, and TNF itself can suppress the growth of lymphoblastoid cells, probably by modulating or competing with LT.(ABSTRACT TRUNCATED AT 400 WORDS