An M/G/1 Retrial Queue with Single Working Vacation

We consider an M=G=1 retrial queue with general retrial times and single working vacation. During the working vacation period, customers can be served at a lower rate. Both service times in a vacation period and in a service period are generally distributed random variables. Using supplementary variable method we obtain the probability generating function for the number of customers and the average number of customers in the orbit. Furthermore, we carry out the waiting time distribution and some special cases of interest are discussed. Finally, some numerical results are presented

Evaluation of Preoperative Hair Removal and its Relationship with Postoperative Wound Infection at a Tertiary Health Facility in North-eastern Nigeria

BACKGROUND: The general surgery unit of Federal Teaching Hospital Gombe performs several surgeries via the hair bearing areas. A pilot study by the unit on the incidence of SSI for all clean surgeries showed an alarming forty- six percent. (38) The reported infection rate for such infection is <2% by CDC standard. This study was done to probe the role of preoperative hair removal in such high infection rate. OBJECTIVES: the study aimed to determine the relative postoperative wound infection rates of Razor blade shaving and cream depilation.  It also assessed the adequacy of hair removal by both methods and the type of skin injuries or reactions that follow each method METHODS: a prospective, cross-sectional, double-blinded study was done between July 1st to December 31st 2016 on 98 patients that met the inclusion criteria and randomized by balloting. BIC shaving stick produced by BIC SOCIETE, FRANCE and VEETO CREAM(thioglycollate) produced by RECKIT BENCKISER, were used for preoperative hair removal. Adequacy of hair removal, post shaving skin injuries and reactions were assessed preoperatively by research assistants. Post-operative wounds were graded using the Southampton wound scoring system for SSI. Data obtained was analyzed with SPSS software version 20.0 and statistical relationships were assessed using Chi-square. RESULTS: a total of 98 patients were recruited for the study. 53(54.1%) were males and 45(45.9%) were females. The mean age was 45.99(+ 12.522) with a range of 16-76 years. Majority (88.8%) had open repair of abdominal wall hernia, followed by Scalp lipoma (6.1%), groin lipoma (3.1%) scalp osteoma and superficial Parotidectomy (1%) each. 57(58.2%) had razor blade shaving and 41(41.8%) had cream depilation. 91(92.9%) had adequate hair removal considering both methods. Depilatory cream use is however, more effective, with (97.6%) adequacy. Razor blade shaving recorded (89.5%) adequacy. Out of the patients, only 4(4.1%) had skin injuries and all are in the razor blade group. Depilatory cream use caused more skin reactions (7.3%) compared to razor blade use (1.8%). 6(6.1%) of all the patients developed SSI and 5(83.3%) (x2 1.6662) are in the razor blade group. Majority of the postoperative wounds (83.3%) are Southampton class A &B. 16.7% is class C  CONCLUSION: preoperative hair removal using razor blade or cream depilation is associated with postoperative wound infection (6.1%). Razor blade shaving is how ever more prone to postoperative wound infection, although, the difference in the infection rate is not statistically significant (p-value 0.197). Preoperative cream depilation is more efficient and safer. LIMITATIONS: The sample size is rather small, as only patients presenting at the general surgery unit were recruited. This limited the scope of subjects that were    assessed, as other units in the surgery department also operate in hair bearing areas. Multiple nurses were involved in the razor blade shaving and cream application, inter-personal differences in technique may affect the outcome in terms of skin injury. Subjective method of direct visual assessment of skin injury was resulting in missing non obvious skin injuries. The use of electron viewing microscope would have improved the discovery of such injuries

An M/G/1 Queue with Server Breakdown and Multiple Working Vavation

This paper deals with the steady state behavior of an M=G=1 multiple working vacation queue with server breakdown. The server works with different service times rather than completely stopping service during a vacation. Both service times in a vacation period and in a regular service period are assumed to be generally distributed random variables. The system may breakdown at random and repair time is arbitrary. Further, just after completion of a customer’s service the server may take a multiple working vacation. Supplementary variable technique is employed to find the probability generating function for the number of customers in the system. The mean number of customers in the system is calculated. Some particular cases of interest are discussed. Numerical results are also presented

Quantification of yield gaps in rain-fed rice, wheat, cotton and mustard in India

Rainfed farming / Crop yield / Simulation / Rice / Wheat / Cotton / Mustard / India

Head-on infall of two compact objects: Third post-Newtonian Energy Flux

Head-on infall of two compact objects with arbitrary mass ratio is investigated using the multipolar post-Minkowskian approximation method. At the third post-Newtonian order the energy flux, in addition to the instantaneous contributions, also includes hereditary contributions consisting of the gravitational-wave tails, tails-of-tails and the tail-squared terms. The results are given both for infall from infinity and also for infall from a finite distance. These analytical expressions should be useful for the comparison with the high accuracy numerical relativity results within the limit in which post-Newtonian approximations are valid.Comment: 25 pages, 2 figures, This version includes the changes appearing in the Erratum published in Phys. Rev.

Higher signal harmonics, LISA's angular resolution, and dark energy

It is generally believed that the angular resolution of the Laser Interferometer Space Antenna (LISA) for binary supermassive black holes (SMBH) will not be good enough to identify the host galaxy or galaxy cluster. This conclusion, based on using only the dominant harmonic of the binary SMBH signal, changes substantially when higher signal harmonics are included in assessing the parameter estimation problem. We show that in a subset of the source parameter space the angular resolution increases by more than a factor of 10, thereby making it possible for LISA to identify the host galaxy/galaxy cluster. Thus, LISA's observation of certain binary SMBH coalescence events could constrain the dark energy equation of state to within a few percent, comparable to the level expected from other dark energy missions.Comment: 15 pages, no figures. Final version to appear in Phys. Rev.

Preliminary Phytochemical Screening of Healthy and Leaf Curl Virus Infected Tomato (Solanum Lycopersicum) Leaves

The present investigation deals with the determination of phytochemical constituents of healthy and leaf curl virus infected tomato (Solanum lycopersicum) leaves. Specimens were collected from Koraye in Zaria and transported to the Herbarium unit for proper authentication. Healthy and curl leaves of Solanum lycopersicum were washed thoroughly three times with running tap water and once with sterile distilled water, air dried at temperature on a sterile blotter. After complete drying, young leaves were pulverized. The powdered material was weighed and kept in air tight container in dark place for further extraction procedure. Extraction was done by methanol method, where 100g each of pulverized powder of both healthy and infected Solanum lycopersicum leaves was put in a cornical flask and (1000ml) of measuring cylinder was used to measure 500ml of 70% methanol. The results obtained from the qualitative phytochemical analysis revealed the presence of; Alkaloids, Flavonoids, Tanins, Cardiac glycosides, Phenols and Saponins in both healthy and infected leaves of Solanum lycopersicum and the absence of; Carbohydrates, Steroids and Anthroquinone in both healthy and infected leaves of Solanum lycopersicum. While the quantitative analysis revealed the presence of 8.2% and 3.8% Alkaloids, 49.6% and 48.2% Flavonoids, 30.6% and 19.99%, Tanins 30.6% and 19.9%, Phenols 13.6% and 7.022% Saponins 1.2% and 0.1% in both healthy and infected leaf curl of Solanum lycopersicum. Evidently, from the above investigation there are no reducing sugars in Solanum lycopersicum leaves and there are metabolites in some healthy and infected leaf curl of Solanum lycopersicum leaves

Breast Cancer Classification Using Deep Convolutional Neural Networks

Breast cancer remains the primary causes of death for women and much effort has been depleted in the form of screening series for prevention. Given the exponential growth in the number of mammograms collected, computer-assisted diagnosis has become a necessity. Histopathological imaging is one of the methods for cancer diagnosis where Pathologists examine tissue cells under different microscopic standards but disagree on the final decision. In this context, the use of automatic image processing techniques resulting from deep learning denotes a promising avenue for assisting in the diagnosis of breast cancer. In this paper, an android software for breast cancer classification using deep learning approach based on a Convolutional Neural Network (CNN) was developed. The software aims to classify the breast tumors to benign or malignant. Experimental results on histopathological images using the BreakHis dataset shows that the DenseNet CNN model achieved high processing performances with 96% of accuracy in the breast cancer classification task when compared with state-of-the-art models