Priority Queueing System with a Single Server Serving Two Queues M[X1],M[X2]/G1,G2/1 with Balking and Optional Server Vacation

In this paper we study a vacation queueing system with a single server simultaneously dealing with an M[x1] /G1/1 and an M[x2] /G2/1 queues. Two classes of units, priority and non-priority, arrive at the system in two independent compound Poisson streams. Under a non-preemptive priority rule, the server provides a general service to the priority and non-priority units. We further assume that the server may take a vacation of random length just after serving the last customer in the priority unit present in the system. If the server is busy or on vacation, an arriving non-priority customer either join the queue with probability b or balks(does not join the queue) with probability (1 - b). The time dependent probability generating functions have been obtained in terms of their Laplace transforms and the corresponding steady state results are obtained explicitly. Also the average number of customer in the priority and the non-priority queue and the average waiting time are derived. Numerical results are computed

Ecology of the cladocerans of the plankton community in the Cochin backwater

Occurrence and seasonal changes in the distribution of two cladocerans in the eochin Backwater, Evadne tergestina Claus and Penilia avirostris Dana have been considered. Fluctuations in temperature of tbe estuary are of the order of SoC., while tbe cbanges in salinity are considerable. Seasonal variation in distribution of tbe two species bas been correlated with temperature and salin ity in T-S-P diagram for a period of fifteen months. Their numerical abundance month-wise bas also been investigated. A comparative study of the distribution of cJadocerans of the insbore waters of India wilh that of the Cochin Backwater has also been carried out

Transient Analysis of M[X1];M[X2]=G1;G2=1 Queueing Model with Retrial Priority Service, Negative Arrival, Two kinds of Vacations, Breakdown, Delayed Repair, Balking, Reneging and Feedback

This paper deals with the analysis of batch arrival retrial queue with two classes non-preemptive priorityunits, negative arrival, balking as well as reneging, feedback, emergency and Bernoulli vacation for anunreliable server. Here we assume that customers arrive according to compound Poisson process inwhich priority customers are assigned to class one and class two customers are of a low-priority type.If the server is free at the time of any batch arrivals, the customers of this batch begins to be servedimmediately. The low-priority customer may join the orbit with feedback if the service is not satisfied(or) may leave the system if the service is satisfied. The priority customers that find the server busyare queued and then served in accordance with FCFS discipline. The priority customers may renegethe queue if the server is not avilable in the system and there is no optional for feedback service tothe priority customers. The arriving low-priority customers on finding the server busy then they arequeued in the orbit in accordance with FCFS retrial policy without balking (or) may balk the orbit.While the server is serving to the customers, it faces two types of break-down there are breakdowns bythe arrival of negative customer and break-down at any instant of service and server will be down for ashort interval of time. Further concept of the delay time of repair is also introduced for breakdowns. Weconsider two different kinds of vacations, one is an emergency and the other one is Bernoulli vacation, theemergency vacation means at the time of the server serving the customer suddenly go for a vacation andthe interrupted customer waits to get the remaining service and after the completion of each service, theserver either goes for a vacation or may continue to serve for the next customer; if any . The retrial time,service time, vacation time, delay time and repair time are all follows general(arbitrary) distribution.Finally, we obtain some important performance measures of this model.Keywords:Batch arrival, priority queue, retrial queue, negative arrival, emergency and Bernoulli vacation, unreliableserver, breakdown and repair.AMSC: 60K25; 60K30; 90B2

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Analysis of M[X1],M[X2]/G1,G2/1 retrial queueing system with priority services, working breakdown, collision, Bernoulli vacation, immediate feedback, starting failure and repair

This paper considers an M[X1] , M[X2] /G1,G2/1 general retrial queueing system with priority services. Two types of customers from different classes arrive at the system in different independent compound Poisson processes. The server follows the non-pre-emptive priority rule subject to working breakdown, Bernoulli vacation, starting failure, immediate feedback, collision and repair. After completing each service, the server may go for a vacation or remain idle in the system. The priority customers who find the server busy are queued in the system. If a low-priority customer finds the server busy, he is routed to orbit that attempts to get the service. The system may become defective at any point of time while in operation. However, when the system becomes defective, instead of stopping service completely, the service is continued to the interrupted customer only at a slower rate. Using the supplementary variable technique, the joint distribution of the server state and the number of customers in the queue are derived. Finally, some performance measures are obtained

Development and Validation of a Dissolution Test Method for Artemether and Lumefantrine in Tablets

Purpose: To develop and validate a dissolution test method for dissolution release of artemether and lumefantrine from tablets.Methods: A single dissolution method for evaluating the in vitro release of artemether and lumefantrine from tablets was developed and validated. The method comprised of a dissolution medium of 1000 ml of 2 %w/v of Myrj 52 in 0.005M HCl per vessel with the paddle rotating at 100 rpm for 120 min. The dissolution samples were analysed using a Waters HPLC system with Waters symmetry column (C-18 column of 250mm x 4.6mm i.d., 5 μ particle size). The mobile phase was a mixture of 20 volumes of 0.5 %v/v of triethylamine in water (adjusted to a pH of 3.0 with orthophosphoric acid) and 80 volumes of acetonitrile. The detection wavelength was set at 216 nm and 100 μl of each sample was injected. The HPLC method used for the determination of drug release was validated for the parameters of accuracy, precision, linearity, specificity, filter validation, solution stability and robustness.Results: The dissolution test provided sink conditions for artemether and lumefantrine and was able to discriminate between tablet formulations of different hardness and different composition. Application of Mann-Whitney U test for significant difference between samples at various time points during the dissolution test yielded z values > 1.96 (1.96 = critical z value at p = 0.05) for the various formulations tested, indicating the discriminatory power of the dissolution test.Conclusion: This validated dissolution test may be used as a single dissolution test for artemether and luminfantrine in tablet formulations.Keywords: Artemether, Lumefantrine, Tablet formulations, Single dissolution test, HPL

Some Notes On Queenfishes And Their Fishery Along The Indian Coasts

A large variety of fishes popularly called horse mackerels, shads, trevellies, queenfishes, pompanos, runners etc. comprise the family Carangidae. Among them, the subfamily Scomberoidae represented by the genus Scomberoides (- Chorinemus) is popularly knownas queenfishes.They form an important constituent in the marine fish landings of India. This article highlights some of the taxonomic characters for easy field identification and also to review in brief the status of fishery of this group of fishe

KNOWLEDGE OF MODIFIABLE RISK FACTORS OF HEART DISEASE AMONG PATIENTS WITH CARDIOVASCULAR RISK

Objectives: Cardiovascular disease (CVD) is one of the leading killer diseases of people around the world. The purpose of this study was to examine the CVD risk factor and perception among individuals with high CVD risk.Methods: An observational study was conducted for 6 months in the Department of General Medicine of a Multi-Specialty Hospital. Patients who were hypertensive, diabetic, and dyslipidemia with/without comorbid disease were included. Patients who are seriously ill, mentally retarded, physical disabilities, history of CVD, etc., were excluded. CVD risk assessment was done using Framingham risk score, and knowledge assessment was done using knowledge questionnaire on CVD risk. Patient counseling was given to the patients based on their risk and knowledge level and also to improve knowledge about CVD risk and therapeutic goals for the control of blood pressure, blood glucose, lipid profile, and smoking cessation.Results: A total of 100 patients were included in this study comprising 46 males and 54 female. Male has more risk than female. The factors, viz., age, smoking habits, high cholesterol, and diabetes mellitus showed a greater risk in CVD. Knowledge levels assessed in those patients are 28% patients having poor knowledge, 30% patients having fair knowledge, and 42% patients having good knowledge.Conclusion: The study concluded that the participants showed poor knowledge in CVD, which could turn into insufficient preventative behaviors and suboptimal patient outcomes. Pharmacist implementation is needed to assess CVD risk and to improve the health-related quality of life.Keywords: Cardiovascular disease risk, Framingham risk score, Knowledge questionnaire

Tidal influence on the diel variations of zooplankton with special reference to copepods in the Cochin Backwater

Diel variations of hydrobiological characters were studied during a complete tidal cycle at a station in the fishing grounds at the lower reaches of Cochin Backwater during November, 1969. The tidal oscillations and the resultant tidal surface currents were found to exert profound influence on these properties. The temperature of the surface water fluctuated depending on solar radiation, whereas, the salinity variations showed a direct relationship with the tides, recording high values during flood tide. Variations in zooplankton biomass appear to be partly influenced by the diel rhythm of plankters, and the incoming tides contribute to their increase during day time. Three broad types of distribution patterns were observed for the different groups of zooplankters depending on their relationship with the tides and diel vertical migrations. Fluctuations in copepod population in the estuary evinced a complex pattern of distribution and the ingress of neritic waters and the diel rhythm were the causative factors for the diel variations in their distribution