Deformable subreflector computed by geometric optics

Using a Cassegrainian geometry, the 64-meter antenna with its distorted paraboloidal reflecting surface is forced to produce a uniform phase wavefront by a pathlength-compensating subreflector. First, the computed distortion vectors at the joints or nodes of the main reflector structure supporting the surface panels are best fitted to a paraboloid. Second, the resulting residual distortion errors are used to determine a compensating subreflector surface by ray tracing using geometric optics principles. Third, the totally corrected subreflector surface is defined by the normal directions and distances to the surface of the original symmetric hyperboloid for the purpose of evaluation. Finally, contour maps of distortions of the paraboloid reflector and the compensating subreflector are presented. A field-measured check of the subreflector in focused position as computed by the described methodology is also presented for the antenna position at horizon look with the geometry at 45 degrees elevation

Studies on Buddleja asiatica antibacterial, antifungal, antispasmodic and Ca++ antagonist activities

Crude extract of Buddleja asiatica Lour and its fractions, chloroform (F1), ethyl acetate (F2) and nbutanol (F3) were evaluated for antibacterial, antifungal, antispasmodic and Ca++ antagonist activities. The antibacterial activity was performed against 11 types of bacteria. The crude extract and fractions F2 and F3 exhibited significant activity, while F1 showed low activity in killing the Shigella flexenari, Sternostoma boydi and Escherichia coli. In the rest bacteria, the crude extract and all the fractions (F1 to F3) revealed minimum to nil inhibitory effect. The fungicidal activity of the crude extract and all the fractions (F1 to F3) was also performed against six different fungi. The crude extract and fractions F1 and F3 displayed significant activity, while fraction F2 showed moderate activity against Fusarium solani. In the case of Microsporum canis, the crude extract and fraction F3 showed high activity but in the other four fungi, the inhibition area exhibited optimum to nil activity in crude extract and all the fractions (F1 to F3). In isolated rabbit jejunum preparations, B. asiatica crude extract caused concentration-dependent (0.03 to 1.0 mg/ml) relaxation of spontaneous and high K+ (80 mM)-induced contractions. The results indicate the antibacterial, antifungal, antispasmodic and Ca++ antagonist potential of B. asiatica Lour.Key words: Buddleja asiatica, antibacterial, antifungal, antispasmodic, Ca++ channel blocker

Blockchain-based DDoS attack mitigation protocol for device-to-device interaction in smart homes

Smart home devices are vulnerable to a variety of attacks. The matter gets more complicated when a number of devices collaborate to launch a colluding attack (e.g. Distributed-Denial-of-Service (DDoS)) in a network (e.g., Smart home). To handle these attacks, most studies have hitherto proposed authentication protocols that cannot necessarily be implemented in devices, especially during Device-to-Device (D2D) interactions. Tapping into the potential of Ethereum blockchain and smart contracts, this work proposes a lightweight authentication mechanism that enables safe D2D interactions in a smart home. The Ethereum blockchain enables the implementation of a decentralized prototype as well as a peer-to-peer distributed ledger system. The work also uses a single server queuing system model and the authentication mechanism to curtail DDoS attacks by controlling the number of service requests in the system. The simulation was conducted twenty times, each with varying number of devices chosen at random (ranging from 1 to 30). Each requester device sends an arbitrary request with a unique resource requirement at a time. This is done to measure the system’s consistency across a variety of device capabilities. The experimental results show that the proposed protocol not only prevents colluding attacks, but also outperforms the benchmark protocols in terms of computational cost, message processing, and response time

Cytotoxicity and phytotoxicity of some selected medicinal plants of the family Polygonaceae

The cytotoxicity of the crude methanolic extracts of Rumex hastatus, Rumex dentatus, Rumex nepalensis, Rheum australe, Polygonum persicaria and Polygonum plebejum (Family Polygonaceae) was determined against Artemia salina at 1000, 100 and 10 mg/ml. R. hastatus, R. dentatus and R. nepalensis showed significant activity at a concentration of 1000 mg/ml against Artemia salina. R. australe showed low activity at 1000 mg/ml and no activity at 100 and 10 mg/ml. At concentration of 10 mg/ml, R. australe showed no activity. Similarly the phytotoxicity of the crude extracts of these six plants was determined against Lemna minor. All the plants except R. hastatus showed significant activity at a concentration of 1000 mg/ml. Moderate activity was shown by R. australe, R. nepalensis and P. persicaria at the concentration of 100 mg/ml. All the plants showed low phytotoxic activity at concentration of 10 mg/ml

Combining ability analysis in Brassica juncea L. for oil quality traits

This study was conducted in Brassica juncea L. for the determination of good combiners for quality associated traits using 8 x 8 diallel during 2004 - 2005 and 2005 - 2006. Analysis of variance revealed highly significant differences (p 0.01) for all the studied traits. Components of combining ability analysis showed that general combining ability (GCA) was highly significant (p 0.01) for oil percentage (%) and glucosinolates (ìMolg-1) whereas the rest were non-significant. Specific combining ability (SCA)effects were highly significant for all traits except for oleic acids. Reciprocal combining ability (RCA) effects were highly significant (p 0.01) for all traits except for oleic acid which was significant at (p 0.05). The SCA effects were higher than RCA for oil %. The GCA effects were of greater magnitude thanthe SCA effects for glucosinolate, erucic acid and protein content. The parental genotypes NUM009, NUM123, NUM105 and NUM117 and their hybrids NUM009x NUM123, NUM103x NUM105, NUM113x NUM124 and NUM103x NUM120 had high GCA and SCA effects, respectively and therefore these could be exploited for further selection of high yielding progenies. The overall study reveals the importance of both additive and non-additive genetic variability suggesting the use of integrated breeding strategies which can efficiently utilize the additive as well as non-additive genetic variability

Quantum oscillations and a non-trivial Berry phase in the noncentrosymmetric superconductor BiPd

We report the measurements of de Haas-van Alphen (dHvA) oscillations in the noncentrosymmetric superconductor BiPd. Several pieces of a complex multi-sheet Fermi surface are identified, including a small pocket (frequency 40 T) which is three dimensional and anisotropic. From the temperature dependence of the amplitude of the oscillations, the cyclotron effective mass is ($0.18$ $\pm$ 0.1) $m_e$. Further analysis showed a non-trivial $\pi$-Berry phase is associated with the 40 T pocket, which strongly supports the presence of topological states in bulk BiPd and may result in topological superconductivity due to the proximity coupling to other bands.Comment: 5 pages, 3 figure

Effect of supervised exercise on physical function and balance in patients with intermittent claudication

Background The aim of the study was to identify whether a standard supervised exercise programme (SEP) for patients with intermittent claudication improved specific measures of functional performance including balance. Methods A prospective observational study was performed at a single tertiary vascular centre. Patients with symptomatic intermittent claudication (Rutherford grades 1–3) were recruited to the study. Participants were assessed at baseline (before SEP) and 3, 6 and 12 months afterwards for markers of lower-limb ischaemia (treadmill walking distance and ankle : brachial pressure index), physical function (6-min walk, Timed Up and Go test, and Short Physical Performance Battery (SPPB) score), balance impairment using computerized dynamic posturography with the Sensory Organization Test (SOT), and quality of life (VascuQoL and Short Form 36). Results Fifty-one participants underwent SEP, which significantly improved initial treadmill walking distance (P = 0·001). Enrolment in a SEP also resulted in improvements in physical function as determined by 6-min maximum walking distance (P = 0·006), SPPB score (P < 0·001), and some domains of both generic (bodily pain, P = 0·025) and disease-specific (social domain, P = 0·039) quality of life. Significant improvements were also noted in balance, as determined by the SOT (P < 0·001). Conclusion Supervised exercise improves both physical function and balance impairment

Role of fibreoptic bronchoscopy in the management of immunocompromised patients with pulmonary infiltrates

Immunocompromised patients are prone to develop various pulmonary complications. The range of diagnostic possibilities is wide, infection being the commonest cause. Non-invasive diagnostic tests are often unrewarding. In this study, we have evaluated the diagnostic efficacy and safety of fibreoptic bronchoscopy in immunocompromised patients with pulmonary infiltrates. Patients tolerated the procedure well. This technique identified the etiology in up tp 75% of cases. After treatment based on the result of bronchoscopy, 63% patients improved and were discharged

A Robust Regression-Based Stock Exchange Forecasting and Determination of Correlation between Stock Markets

Knowledge-based decision support systems for financial management are an important part of investment plans. Investors are avoiding investing in traditional investment areas such as banks due to low return on investment. The stock exchange is one of the major areas for investment presently. Various non-linear and complex factors affect the stock exchange. A robust stock exchange forecasting system remains an important need. From this line of research, we evaluate the performance of a regression-based model to check the robustness over large datasets. We also evaluate the effect of top stock exchange markets on each other. We evaluate our proposed model on the top 4 stock exchanges—New York, London, NASDAQ and Karachi stock exchange. We also evaluate our model on the top 3 companies—Apple, Microsoft, and Google. A huge (Big Data) historical data is gathered from Yahoo finance consisting of 20 years. Such huge data creates a Big Data problem. The performance of our system is evaluated on a 1-step, 6-step, and 12-step forecast. The experiments show that the proposed system produces excellent results. The results are presented in terms of Mean Absolute Error (MAE) and Root Mean Square Error (RMSE)