Analysis of discrete-time queue with two heterogeneous servers subject to catastrophes

This paper studies a discrete-time queueing system with two heterogeneous servers subject to catastrophes. We obtain explicit expressions for the steady-state probabilities at arbitrary epoch using displacement operator method. The waiting time distribution and outside observer’s observation epoch probabilities are deduced. Various performance measures and numerical results have been investigated.Publisher's Versio

Dynamic control and Resource management for Mission Critical Multi-tier Applications in Cloud Data Center

The multi-tier architecture style has become an industry standard in modern data centers with each tier providing certain functionality. To avoid congestion and to adhere the SLA under fluctuating workload and unpredictable failures of Mission Critical Multi-tier applications hosted in the cloud, we need a Dynamic admission control policy, such that the requests must be processed from the first tier to the last without any delay. This paper presents the least strict admission control policy, which will induce the maximal throughput, for a two-tier system with parallel servers. We propose an optimization model to minimize the total number of virtual machines for computing resources in each tier by dynamically varying the mean service rate of the VMs. Some performance indicators and computational results showing the effect of model parameters are presented. This model is also applicable to priority as well as real-time based applications in Cloud based environment

Variant course and branching of right brachial artery: a case study

A variant course and branching pattern of the right brachial artery was recorded in a 54-year-old male cadaver during the practical sessions of University College of Medical Sciences, Delhi, India. The right brachial artery divided in the middle third of arm into a medial superficial and lateral deep branch. The superficial medial branch descended anterior to the median nerve and ended by dividing in the cubital fossa into ulnar and radial arteries, whereas the lateral branch descended postero-medial to the median nerve, ending deep to pronator teres as the common interosseous artery. The left brachial artery showed a normal branching pattern by dividing into radial and ulnar arteries in the cubital fossa. The probable origin of such a variation is embryological and familiarity with such variations is imperative as they might affect dynamics of limb function or alter the course of interventional procedures

Maternal repair system- an analysis in retrospect

Influence of caffeine, cysteine, hydroxyures and cycloherimide on maternal repair system operative in female Drosophila was studied using rod-X males and Oster females. The number of parental matings was kept constant. A new method of statistical analysis was employed to examine the frequency of sex-chromosome loss in these experiments. A re-analysis of published data was also done using this method. The existence of a maternal repair system was not upheld. The observed discrepancies between data reported herein and those published earlier and the possible reasons are discussed

Optimization of renewal input (a, c, b) policy working vacation queue with change over time and bernoulli schedule vacation interruption

This paper presents a renewal input single working vacation queue with change over time and Bernoulli schedule vacation interruption under (a, c, b) policy. The service and vacation times are exponentially distributed. The server begins service if there are at least c units in the queue and the service takes place in batches with a minimum of size a and a maximum of size b (a ≤ c ≤ b). The change over period follows if there are (a − 1) customers at service completion instants. The steady state queue length distributions at arbitrary and pre-arrival epochs are obtained. An optimal cost policy is presented along with few numerical experiences. The genetic algorithm and quadratic fit search method are employed to search for optimal values of some important parameters of the system.Publisher's Versio

5′-Inositol phosphatase SHIP2 recruits Mena to stabilize invadopodia for cancer cell invasion

Invadopodia are specialized membrane protrusions that support degradation of extracellular matrix (ECM) by cancer cells, allowing invasion and metastatic spread. Although early stages of invadopodia assembly have been elucidated, little is known about maturation of invadopodia into structures competent for ECM proteolysis. The localized conversion of phosphatidylinositol(3,4,5)-triphosphate and accumulation of phosphatidylinositol(3,4)-bisphosphate at invadopodia is a key determinant for invadopodia maturation. Here we investigate the role of the 5′-inositol phosphatase, SHIP2, and reveal an unexpected scaffold function of SHIP2 as a prerequisite for invadopodia-mediated ECM degradation. Through biochemical and structure-function analyses, we identify specific interactions between SHIP2 and Mena, an Ena/VASP-family actin regulatory protein. We demonstrate that SHIP2 recruits Mena, but not VASP, to invadopodia and that disruption of SHIP2–Mena interaction in cancer cells leads to attenuated capacity for ECM degradation and invasion in vitro, as well as reduced metastasis in vivo. Together, these findings identify SHIP2 as a key modulator of carcinoma invasiveness and a target for metastatic disease

H.C.G (Human Chorionic Gonadotropin) versus Magnesium sulphate in suppression of preterm labour

Introduction: Preterm labour is a major healthcare problem throughout the world, it is a major cause of perinatal mortality and morbidity. Methods: Prospective comparative study conducted in the Department of Obstetrics & Gynaecology at Kamla Raja Hospital, Gwalior, M.P, from August 2011 to September 2012. Sample Size: 80. 50 patients were given H.C.G. and 30 were given Magnesium sulphate to suppress preterm labour. Statistical analysis done using Chi square test in SPSS software and p value < 0.05 was considered significant. Results: Mean duration between initiation of treatment & suppression of contractions was 3.1 hrs & 2.9 hrs in women receiving H.C.G. & Magnesium sulphate respectively (p value<0.0001). Mean prolongation of pregnancy was 31.4 days and 30.33 days in women receiving H.C.G. & Magnesium sulphate respectively (p value = 0.78). Average rate of labour within 48 hrs after beginning of treatment was 8% and 6.67%, in H.C.G. & Magnesium sulphate grp respectively, p value=0.43. None of the women receiving H.C.G. had any side effects, all 30 women receiving Magnesium sulphate had minor maternal side effects, p value (<0.0001). Mean birth weight was 2.35 kgs and 2.19 kgs respectively in women receiving H.C.G. and Magnesium sulphate reapectively, (p value = 0.22). Conclusion: Magnesium sulphate is better tocolytic drug, showing statistically significant lesser time between the initiation of treatment & suppression of contractions, as compared to H.C.G. Women receiving Magnesium sulphate suffered from minor side effects; however those treated with H.C.G. had no complaints

Analysis of Power Saving Class II Traffic in IEEE 802.16E with Multiple Sleep State and Balking

The battery life of Mobile Stations in IEEE 802.16e can be extended substantially by applying the sleep mode mechanism. This paper studies an effcient method to analyze the performance of the power saving class type II for delay sensitive traffc in multiple sleep state. The incoming data frames may join or balk the buffer due to impatience with some probability. We present an M/M/1/N queueing model with balking and multiple vacations in order to exhibit the self-similar property of IEEE 802.16e. We develop a cost function to determine the optimal service rate that minimizes the total expected cost. Various performance indices such as the average number of data frames in the system, the mean waiting time of the data frame in the system, the the average balking rate due to impatience, etc. have been presented. Numerical results are provided to show the inuence of various parameters on the behavior of the system. The proposed model provides a tradeoff between the average abandon rate and the power consumption