1,387 research outputs found
A Novel Adaptive Channel Allocation Scheme to Handle Handoffs
Wireless networking is becoming an increasingly important and popular way of
providing global information access to users on the move. One of the main
challenges for seamless mobility is the availability of simple and robust
handoff algorithms, which allow a mobile node to roam among heterogeneous
wireless networks. In this paper, the authors devise a scheme, A Novel Adaptive
Channel Allocation Scheme (ACAS) where the number of guard channel(s) is
adjusted automatically based on the average handoff blocking rate measured in
the past certain period of time. The handoff blocking rate is controlled under
the designated threshold and the new call blocking rate is minimized. The
performance evaluation of the ACAS is done through simulation of nodes. The
result shows that the ACAS scheme outperforms the Static Channel Allocation
Scheme by controlling a hard constraint on the handoff rejection probability.
The proposed scheme achieves the optimal performance by maximizing the resource
utilization and adapts itself to changing traffic conditions automatically.Comment: 9 Pages; in International Journal of Distributed and Parallel system
Computation of aquifer parameters using geo-electrical techniques for the North Chennai coastal aquifer
1298-1306Computation of aquifer characteristics, such as hydraulic conductivity, transmissivity, formation factor, and porosity utilizing the geophysical method is less complex compared to that using arduous pumping test. Vertical electrical soundings directed in 33 areas in the north Chennai coastal aquifer in the Araniyar–Kosasthalaiyar basin demonstrates that the geo-electrical technique is a valuable tool to assess subsurface development and aquifer parameters. High values of hydraulic conductivity and transmissivity were recorded in the western part of the investigated region. Spatial conveyance of Dar Zarrouk parameters and aquifer parameters are helpful in evaluating the examined territory and for finding the favorable area for extraction. This study demonstrates that aquifer properties of coastal area are found to improve while moving away from the drift. Aquifer parameters were calculated using a pumping test and a geophysical technique in the examined zone and they were found to match. The investigation demonstrates that the geo-electrical study is a good alternative for the estimation of aquifer parameters instead of the laborious pumping tests
Efficacy and safety of long-acting β-agonist/long-acting muscarinic antagonist combinations in COPD:a network meta-analysis
BackgroundThe place of long-acting β agonist/long-acting muscarinic antagonist (LABA/LAMA) combinations in stable patients with COPD is not well defined. The purpose of this study was to systematically review the efficacy and safety of LABA/LAMA combinations.MethodsSeveral databases and manufacturers’ websites were searched for relevant clinical trials. Randomised control trials, at least 12 weeks duration, comparing a LABA/LAMA combination with placebo and/or monotherapy were included. The data were pooled using a network as well as a traditional direct comparison meta-analysis.ResultsTwenty-three trials with a total of 27 172 patients were included in the analysis. LABA/LAMA combinations were associated with a greater improvement in lung function, St. George's Respiratory Questionnaire (SGRQ) score, and Transitional Dyspnoea Index (TDI) than monotherapies. LABA/LAMA combinations were associated with a significantly greater proportion of SGRQ and TDI responders than monotherapies (OR 1.23 (95% credible interval (CrI) 1.06–1.39), OR 1.34 (95% CrI 1.19–1.50) versus LABAs and OR 1.24 (95% CrI 1.11–1.36), OR 1.31 (95% CrI 1.18–1.46) versus LAMAs, respectively) and fewer moderate-to-severe exacerbations compared with LABAs (HR 0.82 (95% CrI 0.73–0.93)), but not when compared with LAMAs (HR 0.92 (95% CrI 0.84–1.00)). There were no statistically significant differences associated with LABA/LAMA combinations compared with monotherapies in safety outcomes as well as in severe exacerbations.ConclusionsThe combination therapy was the most effective strategy in improving lung function, quality of life, symptom scores and moderate-to-severe exacerbation rates, and had similar effects on safety outcomes and severe exacerbations as compared with monotherapies.</jats:sec
Prediction of non-centrosymmetric packing for 1,3-disubstituted nitro aromatics. Crystal and molecular structure of 3-hydroxy-6-(3'-nitro)-phenylazopyridine
The crystal and molecular structure of 3-hydroxy-6-(3'-nitro)-phenylazopyridine is reported. The crystals are non-centrosymmetric, Pna21, Z = 4, a = 16.522(3), b = 8.402(2), c = 7.945(1) Å, and the structure refined to an R-value of 0.046 on 1086 non-zero reflections. The molecule exists as the hydroxyazo tautomer and is intermolecularly O-H … N hydrogen bonded in the crystal. The title compound is one of several 1,3-disubstituted benzenes which adopt non-centrosymmetric packing, a necessary prerequisite for nonlinear second harmonic generation. Analysis of nearly 600 nitroaromatic crystal structures retrieved from the Cambridge Structural Database shows that 1,3-disubstitution significantly increases the probability of non-centrosymmetric space group adoption when compared to 1,2 or 1,4-disubstitution. Similar though less pronounced trends are observed for trisubstituted and higher derivatives
PILOT STUDY ON PHARMACEUTICAL PROCESS OF MAMSA ARKA - A FORGOTTEN AMBROSIA
Arka kalpana (distillation) is a unique preparation of Bhaishajya kalpana. Mamsa Arka (meat distillate) among Arka kalpana is not much popular these days. It is practically forgotten and not practiced in modern Ayurveda. In classical literature Mamsa Arka is compared to ambrosia and best of all Arka formulations. Its properties are Maha Swadu (relishing) and Adhika rochana (enhances taste). It is also specifically given to certain patients having aversion to meat. Present study focuses on the pharmaceutical preparation of Mamsa Arka with special reference to Arka prakasa and performing organoleptic tests on the sample obtained. Experiment was done on a household stove to specify that Mamsa Arka can be prepared in small scale by the practitioner himself with ease. Simple distillation apparatus was used for the procedure. Temperature was maintained around 1200 to 1300 Celsius throughout the process with the help of thermometer which lasted for 1 ½ hour. The resultant distillate obtained was 1/3rd (33.3 % approx.) of the total liquid content in the mixture. Mamsa Arka is a colourless liquid with a specific odour dominated by Lavanga and Karpura. It is a palatable product with Madhura (Sweet), Tikta (Bitter) and slightly Katu (Pungent) Rasa (taste). Mamsa Arka is considered Laghu (light in digestion), Balya (strength promoting) and fast acting.
A STUDY ON QUANTITY OF Bt TOXIN IN Bt AND NBt COTTON RHIZOSPHERE
Genetically engineered plants and their residues may pose direct or indirect impacts on different ecosystem functions. The aim of this experiment was to determine the amount of Bt toxin (Cry 1 Ac δ endotoxin) present in the rhizosphere of Bt cotton during the crop period at regular intervals. Bt toxin was estimated from the rhizospheric soils of near isogenic Non Bt cotton crop for as a control. Cry 1 Ac δ endotoxin was estimated using Envirologix Quanti Kit plate (ELISA) method. The soil samples were collected in which Bt cotton was cultivating for more than ten years as monocrop, similarly Non Bt cotton fields where never cultivated transgenic crop were selected for this study. The quantity of the Cry 1Ac toxin levels in the rhizosphere of Bt cotton was estimated at different crop stages and it was 41.13 ppb at pre cultivation stage which is higher than that of Non Bt rhizosphere soil i.e.15.3 ppb. The toxin concentration increased gradually during different crop stages i.e 69.32 ppb, 95.24 ppb, 103.35 ppb at 30, 60,90 days crop stages respectively. It was decreased to 92.37 ppb at harvest stage and shown higher levels (173.24 ppb) at postharvest stage. But in case of Non Bt rhizosphere it is almost same at all the stages of crop. The results suggests that there is a significant difference between the Bt and Non Bt soils with respect to quantity of Cry toxin and there is also significant difference between different crop stages of Bt cotton with respect to Non Bt cotto
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