Energy Efficient Inactive Node Detection Based Routing Protocol for Delay Tolerant Network

Wireless Personal Communications - The delay tolerant network multi-copy protocols create and transmit multiple copies of each message that overload the buffer size, energy and bandwidth. The...     

Numerical assessment of the mechanical stability in vertical,directional and horizontal wellbores

In this research the stability of wellbore is evaluated in seven different stress regimes and diverse orientations using FLAC3D software. The normalized yielded zone area (NYZA, i.e., the ratio of surrounding yielded cross-sectional area to initial area of wellbore) is determined for different mud pressures as well as diverse orientations of wellbore. By means of MATLAB software the best curve is fitted to the recorded points and then the optimized mud pressure is calculated using these plots. The optimized orientation is selected considering these data. Finally the mud pressure resulted from this method was compared with the mud pressure obtained from the Mogi-Coulomb criterion and then with the fields data. The minimum allowable mud pressure obtained from the NYZA criterion is close to actual data and the value obtained from the Mogi-Coulomb criterion. Hence, the NYZA is considered to be an appropriate criterion for wellbore stability analysis.     

The nature of the gregarizing signal responsible for maternal transfer of phase to the offspring in the desert locust Schistocerca gregaria

We examined aggregative behavior of hatchlings of the desert locust Schistocerca gregaria emerging from solitaria egg pods that had been incubated in sand previously used for consecutive ovipositions by gregarious females. Hatchlings derived from such eggs were significantly more gregarious than those derived from pods laid in clean sand. The gregarizing effect of the sand-associated factor originating from 3, 5, or 10 ovipositions by gregarious females increased in a dose-dependent fashion. Washing the sand with organic solvents following such ovipositions, or flushing it with nitrogen gas, led to substantial loss of its gregarizing effect, showing that the active signal is volatile and of medium polarity. The gregarizing activity of the exposed sand correlated with the presence of C-8 unsaturated ketones, (Z)-6-octen-3-one and (E,E)-3,5-octadiene-2-one and its E,Z isomer, previously shown by us to form part of the releaser pheromone system that mediates group oviposition in S. gregaria. These ketones were present in relatively large amounts in the eggs obtained from egg pods of gregarious females and were also detected in the extracts of accessory glands of gregarious females, a candidate source of the gregarization factor. It is proposed that the pheromone is secreted at the onset of oviposition. This would account for its distribution predominantly within the eggs and surrounding sand at the site of oviposition. The study sheds new light on the pheromonal mechanism associated with transgenerational transmission of gregarious characters in crowded S. gregaria populations and provides yet another case in this insect of dual releaser and primer roles played by the same pheromone blend.     

On the explicit analytic solutions of an Oldroyd 6-constant fluid

This paper deals with some steady unidirectional flows of an Oldroyd 6-constant fluid. The modelled differential equation is non-linear and proposes some new mathematical difficulties. The governing non-linear equation for the steady flow of an Oldroyd 6-constant fluid is different than from the Newtonian fluid and involves the non-Newtonian features. Moreover, the exact analytic solutions are obtained for Couette, Poiseuille and generalized Couette flows for all values of non-Newtonian parameters. The homotopy analysis method (HAM) is used to construct the solutions.     

A comparison of techniques for solving the fleet size and mix vehicle routing problem

Summary In the fleet size and mix vehicle routing problem, one decides upon the composition and size of a possibly heterogeneous fleet of vehicles so as to minimize the sum of fixed vehicle acquisition costs and routing costs for customer deliveries. This paper reviews some existing heuristics for this problem as well as a lower bound procedure. Based on the latter, a new heuristic is presented. Computational results are provided for a number of benchmark problems in order to compare the performance of the different solution methods.

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Zusammenfassung Das Problem der Bestimmung einer optimalen Anzahl von möglicherweise verschiedenen Fahrzeugen in einem Fuhrpark sowie die bestmögliche Zusammensetzung verschiedener Fahrzeuge bei der Tourenplanung, wobei die Fixkosten der Beschaffung und die Kosten für die laufende Unterhaltung der Routen minimiert werden soll, wird diskutiert. Einige bekannte Heuristiken und ein Algorithmus zur Bestimmung einer unteren Schranke werden besprochen. Mit diesen Grundlagen wird eine neue Heuristik vorgeschlagen. Um die Leistungsfähigkeit der verschiedenen Lösungsmethoden zu vergleichen, werden anschließend Rechenergebnisse verschiedener benchmark Probleme vorgestellt.

     

Dynamics and the single spike

Responses of vestibular primary afferent neurons to head rotation exhibit fractional-order dynamics. As a consequence, the head tends to be in a localized region of its state-space at spike times of a particular neuron during arbitrary head movements, and single spikes can be interpreted as state measurements. We are developing a model of neural computations underlying trajectory prediction and control tasks, based on this experimental observation. This is a step toward a formal neural calculus in which single spikes are modeled realistically as the operands of neural computation.     

Topical Delivery of Fluconazole: In Vitro Skin Penetration and Permeation Using Emulsions as Dosage Forms

ABSTRACT

We investigated in vitro skin penetration and permeation of fluconazole from emulsions containing different penetration enhancers. Fluconazole permeation was high (15–65% of the applied dose) across hairless mouse skin and low (8–9%) across pig ear skin. Permeation across mice skin from a formulation containing propyleneglycol and isopropyl myristate was significantly higher than that observed with the paraffin oil and propyleneglycol or Transcutol® emulsions. With pig skin, the paraffin oil or isopropyl myristate and propyleneglycol emulsions showed similar skin permeation and penetration. However, these emulsions provided epidermal concentrations higher than the minimal inhibitory concentrations for most dermatophytes.