2,155 research outputs found

    DVB-RCS return link radio resource management for broadband satellite systems using fade mitigation techniques at ka band

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    Current Broadband Satellite systems supporting DVB-RCS at Ku band have static physical layer in order not to complicate their implementation. However at Ka band frequencies and above an adaptive physical layer wherein the physical layer parameters are dynamically modified on a per user basis is necessary to counteract atmospheric attenuation. Satellite Radio Resource Management (RRM) at the Medium Access Control (MAC) layer has become an important issue given the emphasis placed on Quality of Service (QoS) provided to the Users. The work presented here tackles the problem of Satellite RRM for Broadband Satellite systems using DVB-RCS where a fully adaptive physical layer is envisaged at Ka band frequencies. The impact of adaptive physical layer and user traffic conditions on the MAC layer functions is analyzed and an algorithm is proposed for the RRM process. Various physical layer issues associated with the resource management problem are also analyzed

    Impact of histone H4 lysine 20 methylation on 53BP1 responses to chromosomal double strand breaks.

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    Recruitment of 53BP1 to chromatin flanking double strand breaks (DSBs) requires γH2AX/MDC1/RNF8-dependent ubiquitination of chromatin and interaction of 53BP1 with histone H4 methylated on lysine 20 (H4K20me). Several histone methyltransferases have been implicated in 53BP1 recruitment, but their quantitative contributions to the 53BP1 response are unclear. We have developed a multi-photon laser (MPL) system to target DSBs to subfemtoliter nuclear volumes and used this to mathematically model DSB response kinetics of MDC1 and of 53BP1. In contrast to MDC1, which revealed first order kinetics, the 53BP1 MPL-DSB response is best fitted by a Gompertz growth function. The 53BP1 MPL response shows the expected dependency on MDC1 and RNF8. We determined the impact of altered H4K20 methylation on 53BP1 MPL response kinetics in mouse embryonic fibroblasts (MEFs) lacking key H4K20 histone methyltransferases. This revealed no major requirement for the known H4K20 dimethylases Suv4-20h1 and Suv4-20h2 in 53BP1 recruitment or DSB repair function, but a key role for the H4K20 monomethylase, PR-SET7. The histone methyltransferase MMSET/WHSC1 has recently been implicated in 53BP1 DSB recruitment. We found that WHSC1 homozygous mutant MEFs reveal an alteration in balance of H4K20 methylation patterns; however, 53BP1 DSB responses in these cells appear normal

    A checking method for probabilistic seismic-hazard assessment: case studies on three cities

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    The conventional Cornell's source-based approach of probabilistic seismic-hazard assessment (PSHA) has been employed all around the world, whilst many studies often rely on the use of computer packages such as FRISK (McGuire FRISK-a computer program for seismic risk analysis. Open-File Report 78-1007, United States Geological Survey, Department of Interior, Washington 1978) and SEISRISK III (Bender and Perkins SEISRISK III-a computer program for seismic hazard estimation, Bulletin 1772. United States Geological Survey, Department of Interior, Washington 1987). A "black-box" syndrome may be resulted if the user of the software does not have another simple and robust PSHA method that can be used to make comparisons. An alternative method for PSHA, namely direct amplitude-based (DAB) approach, has been developed as a heuristic and efficient method enabling users to undertake their own sanity checks on outputs from computer packages. This paper experiments the application of the DAB approach for three cities in China, Iran, and India, respectively, and compares with documented results computed by the source-based approach. Several insights regarding the procedure of conducting PSHA have also been obtained, which could be useful for future seismic-hazard studies. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

    Synthesis, preclinical evaluation and antidepressant activity of 5-substituted phenyl-3-(thiophen-2-yl)-4, 5-dihydro-1H-pyrazole-1-carbothioamides

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    A series of phenyl-3-(thiophen-2-yl)-4, 5-dihydro-1H-pyrazole-1-carbothioamides (TTa-TTg) were synthesized by the ring closure reaction of phenyl-1-(thiophen-2-yl) prop-2-en-1-ones with thiosemicarbazide in alcoholic basic medium. All the final derivatives were evaluated for their antidepressant and neurotoxicity screening. The structures of the compounds were characterized by IR, 1H NMR, 13C NMR, Mass and elemental analyses. Preclinical evaluation of the compounds were ascertained by in silico toxicity, blood-brain barrier and human oral absorption prediction. In this series, 5-(4-hydroxyphenyl)-3-(thiophen- 2-yl)-4,5-dihydro-1H-pyrazole-1 carbothioamide (TTg) reduced immobility time 61.17 and 62.05 % in both force swimming and tail suspension test respectively at 10 mg/kg dose level when compared to the standard Imipramine without influencing the baseline locomotion. Moreover it was observed that the titled scaffold possessing electron withdrawing chlorine atom in the 4th position of aromatic ring of the scaffold also showed good the antidepressant activity. In conclusion, the behavioural investigation revealed that thiophene based pyrazolines having a carbothioamide tail unit in the N1 position may be therapeutically useful as potential antidepressant medications

    An (S - 1; S) Inventory System with Negative Arrivals and Multiple Vacations

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    In this paper, we consider a continuous review one-to-one ordering policy inventory system with multiple vacations and negative customers. The maximum storage capacity is S. The customers arrive according to a Poisson process with finite waiting hall. There are two types of customers: ordinary and negative. An ordinary customer, on arrival, joins the queue and the negative customer does not join the queue and takes away any one of the waiting customers. When the waiting hall is full, the arriving primary customer is considered to be lost. The service time and lead time are assumed to have independent exponential distribution. When the inventory becomes empty, the server takes a vacation and the vacation duration is exponentially distributed. The stationary distribution of the number of customers in the waiting hall, the inventory level and the server status for the steady state case. Some system performance measures and numerical illustrations are discussed

    In vitro production of Kaempferia galanga (L.)- an endangered medicinal plant

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    Kaempferia galanga is an important medicinal plant that is facing threat of extinction owing to indiscriminate and unsustainable harvesting in the wild. Conventional breeding is difficult in this plant, and in vitro multiplication is important to conservation and propagation. Tissue culture techniques are useful for ex situ conservation of rare, endemic or threatened plant species. An efficient protocol has been established for rapid production of plantlets using rhizome tip and lateral bud of the pot cultured plant. The explants were cultured on MS medium with various combinations of 6-benzyladenine (BA), α-naphthalene acetic acid (NAA), indole-3-butric acid (IBA) and indole-3-acetic acid (IAA) at concentrations ranging from 0.1 to 3.0 mg/l. High-frequency organogenesis and multiple shoot regeneration were induced from rhizome explants on MS medium supplemented with 2.0 mg/l of BA and 0.2 mg/l of NAA. Micro-shoots were isolated from the in vitro proliferated cluster of shoots and they produced roots on half strength MS medium supplemented with 1.0 mg/l of IBA. The regenerated plantlets were transferred to plastic pots for hardening in a mixture containing red soil, sand and vermiculate(1:1:1) ratio and established on the soil with 81% of success

    Review on the Design of the Isolation Techniques for UWB-MIMO Antennas

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    Ultra wide band - Multiple Input Multiple Output antenna technology provides higher data rates and the combination of the ultra wide band (UWB) and the multiple input multiple output (MIMO) technologies provides a solution for the demand of still higher data rates i.e. in excess of 3 Gb/sec in the future.  As the antenna technologies are improving, the size of the MIMO antenna is growing smaller and smaller. Placing the antenna elements in such close proximity increases the coupling between them. Various isolation techniques have to be introduced between the antenna elements to decrease the coupling and to improve the isolation. A study of the various isolation enhancement techniques have been made in this review. It analyses the various isolation enhancement methods such as using orthogonal polarization, parasitic elements, varied decoupling structures, defected ground structures (DGS), neutralization line (NL) and finally by using metamaterials. Metamaterials is a technology to perk up the isolation between the antenna elements. Split ring resonator (SRR) behaves as a metamaterial and it is used as an isolation mechanism in this study. The antennas are simulated and the results are compared. The method using parasitic elements gives the highest isolation of 35 dB and it is 5 dB better than the methods using orthogonal polarization and using the decoupling structure. The performance of all the antennas satisfies the conditions for minimum isolation. The envelope correlation coefficient is nearly zero in all the antennas and it implies good diversity performance. The diversity gain is also calculated for the various antennas and it satisfies good diversity performance. The bandwidth of the antennas is in the UWB frequency range and they have a fractional bandwidth above the required value of 1.09. The capacity loss for all the antennas is very low and the antennas using defected ground structure and the decoupling structure gives very low capacity loss

    Intergenerational relationship and Multi-trait Genotype-Ideotype Distance Indexing (MGIDI) in inter-varietal cross derivatives of black gram [Vigna mungo (L.) Hepper.

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    Black gram is a highly self-pollinated short-duration crop cultivated in various cropping systems viz., rainfed, intercrop and rice fallow. In the present study, hybridization was made between 2 black gram varieties viz., CO 6 and VBN 11, aimed to develop the recombinants and select superior progenies through Multi-trait Genotype-Ideotype Distance Index (MGIDI) at Tamil Nadu Agricultural University, Coimbatore. The parent-offspring regression analysis was carried out in the F3 and F4 progenies of CO 6 × VBN 11. The significant regression and intergenerational correlation coefficients were observed for all the traits studied. The narrow sense heritability was found to be high for the number of seeds per pod. The other traits viz., plant height, number of branches per plant, number of clusters per plant, number of pods per cluster, number of pods per plant, pod length, number of seeds per pod, hundred seed weight and seed yield per plant showed moderate narrow sense heritability. The MGIDI was calculated for 62 F4 progenies of CO 6 × VBN 11 considering nine yield component traits. In F4 progenies, high broad sense heritability was observed for all the yield-contributing traits and high selection gain was recorded for seed yield per plant (49.77%), number of branches per plant (46.29%), number of pods per plant (37.74%) and number of pods per cluster (20.80%). Based on the MGIDI, six F4 progenies viz., P1, P6, P22, P49, P50 and P53 were selected. The selected progenies could be further evaluated and yield tested for commercial exploitation
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