Geometrical Properties of Coupled Oscillators at Synchronization

We study the synchronization of $N$ nearest neighbors coupled oscillators in a ring. We derive an analytic form for the phase difference among neighboring oscillators which shows the dependency on the periodic boundary conditions. At synchronization, we find two distinct quantities which characterize four of the oscillators, two pairs of nearest neighbors, which are at the border of the clusters before total synchronization occurs. These oscillators are responsible for the saddle node bifurcation, of which only two of them have a phase-lock of phase difference equals $\pm$$\pi$/2. Using these properties we build a technique based on geometric properties and numerical observations to arrive to an exact analytic expression for the coupling strength at full synchronization and determine the two oscillators that have a phase-lock condition of $\pm$$\pi$/2.Comment: accepted for publication in "Communications in Nonlinear Science and Numerical Simulations

Flow Injection Potentiometric Assay of Hexoprenaline in Its Pure State, Pharmaceutical Preparations, and Biological Samples

Different hexoprenaline (Hx2SO4) conventional and coated wire electrodes were constructed and evaluated. Membranes were based on hexoprenalinium phosphotungstate (Hx-PTA) and hexporenalinium phosphomolybdate (Hx-PMA). The electrodes were fully characterized in terms of their composition, response time, life span, pH, and temperature and then were applied to the potentiometric determination of the hexoprenalinium ion in its pure state, pharmaceutical preparations, and biological samples, urine and plasma, under batch and flow injection conditions. The selectivity of the electrodes towards many inorganic cations, sugars, amino acids, and some other brochodilatures of close chemical composition was also tested

"Dissecting the poisoned honey" : Sexist Humor in Egypt: A linguistic analysis of sexism in Colloquial Cairene Arabic jokes

This paper attempts to shed light on sexism in Egyptian Internet jokes. It examines how language, as an institution largely controlled by men, is manipulated and used to disparage women in this discursive mode of humor. Through running a qualitative and quantitative analysis of 284 sexist internet jokes, the study addressed three points; namely, the most frequently targeted category of women in sexist jokes; the most salient physical and personal attributes and finally the way sexist jokes is used to promote violence against women. The analysis has shown that the "wife" is the category most ridiculed. The data also revealed that in spite of the freedom in anonymity that the internet provides, personal attributes far outnumber the physical features. The jokes conformed to the conservative nature of the society as derision of physical features was done through the use of general terms. The analysis has shown that 'hatefulness' was the most highly criticised personal attribute, with "stupidity" coming second. It was also shown that under the guise of benign amusement, the effect of these jokes go beyond tolerating gender inequality to actually promoting physical violence against women. We conclude that in a patriarchal social system like that of Egypt, which already disparages women as the 'marked' and the 'different', such jokes should not be dismissed lightly as "just jokes".Este artículo trata de arrojar luz sobre el sexismo en los chistes de Internet egipcios. Examina cómo el lenguaje, entendido como una institución controlada en gran medida por los hombres, es manipulado y utilizado para desacreditar a las mujeres en esta modalidad discursiva del humor. El estudio consta de un análisis cualitativo y cuantitativo de 284 chistes sexistas de Internet

Accuracy of Ultrasound Diagnosis after Blunt Scrotal Trauma (10 Years Experience)

Objectives: To evaluate the role of ultrasonography (US) and its accuracy, sensitivity and specificity for the diagnosis of testicular rupture after blunt scrotal trauma. Moreover, tunica albuginea breach, testicular hematoma, testis avulsion, epididymal injuries and hematocele are particularly examined.Patients and Methods: Between 1998 and 2008, 24 patients presented to Suez Canal University Hospital after blunt scrotal trauma and underwent surgical exploration. All patients had an emergency scrotal US examination with the use of a 7.5-10 MHz linear transducer. US findings were compared with the surgical findings to calculate the sensitivity and specificity of US for each type of lesion.Results: Out of 24 patients, 12 were diagnosed as having testicular rupture and tunica albuginea breach was visualized on US in 6 patients. Sensitivity and specificity of US were 92% and 50% for testicular rupture, 85% and 75% for hematocele, 80% and 79% for testicular hematoma, and 100% and 96% for testicular avulsion, respectively. US diagnosis of epididymal injuries was poor as it failed to detect 3 out of 5 epididymal lesions.Conclusion: US was highly sensitive in the diagnosis of testis rupture. This can provide information on the integrity of the scrotal contents that can help the physician to determine the optimal treatment.Key Words: Ultrasonography, scrotal blunt trauma, testis ruptur

Parametric test of a zirconium (4) oxide-polyacrylic acid dual layer hyperfiltration membrane with spacecraft washwater

Performance data consisting of solute rejections and product flux were measured, as dependent on the operation parameters. These parameters and ranges were pressure (500,000 n/m2 to 700,000 n/m2), temperature (74 C to 95 C), velocity (1.6 M/sec to 10 M/sec), and concentration (up to 14x). Tests were carried out on analog washwater. Data presented include rejections of organic materials, ammonia, urea, and an assortment of ions. The membrane used was deposited in situ on a porcelain ceramic substrate

Analytical calculation of the transition to complete phase synchronization in coupled oscillators

Here we present a system of coupled phase oscillators with nearest neighbors coupling, which we study for different boundary conditions. We concentrate at the transition to total synchronization. We are able to develop exact solutions for the value of the coupling parameter when the system becomes completely synchronized, for the case of periodic boundary conditions as well as for an open chain with fixed ends. We compare the results with those calculated numerically.Comment: 5 pages, 3 figure

Multi-vehicle Dispatching And Routing With Time Window Constraints And Limited Dock Capacity

The Vehicle Routing Problem with Time Windows (VRPTW) is an important and computationally hard optimization problem frequently encountered in Scheduling and logistics. The Vehicle Routing Problem (VRP) can be described as the problem of designing the most efficient and economical routes from one depot to a set of customers using a limited number of vehicles. This research addresses the VRPTW under the following additional complicating features that are often encountered in practical problems: 1. Customers have strict time windows for receiving a vehicle, i.e., vehicles are not allowed to arrive at the customer’s location earlier than the lower limit of the specified time window, which is relaxed in previous research work. 2. There is a limited number of loading/unloading docks for dispatching/receiving the vehicles at the depot The main goal of this research is to propose a framework for solving the VRPTW with the constraints stated above by generating near-optimal routes for the vehicles so as to minimize the total traveling distance. First, the proposed framework clusters customers into groups based on their proximity to each other. Second, a Probabilistic Route Generation (PRG) algorithm is applied to each cluster to find the best route for visiting customers by each vehicle; multiple routes per vehicle are generated and each route is associated with a set of feasible dispatching times from the depot. Third, an assignment problem formulation determines the best dispatching time and route for each vehicle that minimizes the total traveling distance. iii The proposed algorithm is tested on a set of benchmark problems that were originally developed by Marius M. Solomon and the results indicate that the algorithm works well with about 1.14% average deviation from the best-known solutions. The benchmark problems are then modified by adjusting some of the customer time window limits, and adding the staggered vehicle dispatching constraint. For demonstration purposes, the proposed clustering and PRG algorithms are then applied to the modified benchmark problems