Reducing Congestion Effects by Multipath Routing in Wireless Networks

We propose a solution to improve fairness and increasethroughput in wireless networks with location information.Our approach consists of a multipath routing protocol, BiasedGeographical Routing (BGR), and two congestion controlalgorithms, In-Network Packet Scatter (IPS) and End-to-EndPacket Scatter (EPS), which leverage BGR to avoid the congestedareas of the network. BGR achieves good performancewhile incurring a communication overhead of just 1 byte perdata packet, and has a computational complexity similar togreedy geographic routing. IPS alleviates transient congestion bysplitting traffic immediately before the congested areas. In contrast,EPS alleviates long term congestion by splitting the flow atthe source, and performing rate control. EPS selects the pathsdynamically, and uses a less aggressive congestion controlmechanism on non-greedy paths to improve energy efficiency.Simulation and experimental results show that our solutionachieves its objectives. Extensive ns-2 simulations show that oursolution improves both fairness and throughput as compared tosingle path greedy routing. Our solution reduces the variance ofthroughput across all flows by 35%, reduction which is mainlyachieved by increasing throughput of long-range flows witharound 70%. Furthermore, overall network throughput increasesby approximately 10%. Experimental results on a 50-node testbed are consistent with our simulation results, suggestingthat BGR is effective in practice

Torsion of an appendiceal mucinous cystadenoma. Report of a case and review of literature

Laboratorul de chirurgie hepato-pancreato-biliară, Catedra de chirurgie nr. 1 „Nicolae Anestiadi”, USMF „Nicolae Testemițanu”, IMSP Institutul de Medicină Urgentă, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Introducere. Torsiunea apendicelui vermicular este rară, şi mai rară fiind torsiunea tumorilor apendiculare mucinoase. Doar nouă cazuri de torsiune a tumorilor apendiculare mucinoase sunt descrise în prezent. Material şi metodă. Prezentăm cazul clinic de torsiune secundară a apendicelui cecal cu chistadenom mucinos la un pacient de 30 ani. Rezultate. Semnele clinice au fost similare unei apendicite acute. Laparoscopia diagnostică a pus în evidenţă o tumoare mucinoasă apendiculară torsionată la 360 grade. Pentru a evita diseminarea peritoneală a fost efectuată apendicectomia deschisă. Examenul histopatologic a confirmat chistadenom mucinos apendicular. Evoluţia postoperatorie a fost fără complicaţii. Concluzie. Torsiunea secundară a apendicelui cecal provocată de chistadenom mucinos apendicular este rară. Diagnosticul corect preoperator este puţin probabil. Apendicectomia deschisă este metoda standard de tratament pentru tumorile mucinoase benigne ale apendicelui cecal. Semnificaţie deosebită trebuie atribuită prevenţiei diseminării conţinutului apendicular.Introduction. Vermiform appendix torsion is rare, and even more uncommon is the volvulus of appendiceal mucinous tumors. To our knowledge, only nine cases of torsion of the vermiform appendix associated with appendiceal mucinous neoplasms have been reported up to date. Material & methods. We report a case of secondary torsion of the vermiform appendix with mucinous cystadenoma in a 30-year-old man. Results. The symptoms were consistent with acute appendicitis. Diagnostic laparoscopy revealed a mucinous tumor of the appendix with a 360 degrees twisted appendix. In order to avoid peritoneal dissemination open appendectomy was performed. The final pathologic diagnosis was a mucinous cystadenoma of the appendix. The postoperative recovery was uneventful. Conclusion. Secondary torsion of vermiform appendix with mucinous cystadenoma is a rare entity. Correct preoperative diagnosis is unlikely. Open appendectomy is the standard of care for benign mucinous appendiceal tumors. Furthermore, it is important to prevent spillage of the appendiceal mucocele content

High temperature ferromagnetism of Li-doped vanadium oxide nanotubes

The nature of a puzzling high temperature ferromagnetism of doped mixed-valent vanadium oxide nanotubes reported earlier by Krusin-Elbaum et al., Nature 431 (2004) 672, has been addressed by static magnetization, muon spin relaxation, nuclear magnetic and electron spin resonance spectroscopy techniques. A precise control of the charge doping was achieved by electrochemical Li intercalation. We find that it provides excess electrons, thereby increasing the number of interacting magnetic vanadium sites, and, at a certain doping level, yields a ferromagnetic-like response persisting up to room temperature. Thus we confirm the surprising previous results on the samples prepared by a completely different intercalation method. Moreover our spectroscopic data provide first ample evidence for the bulk nature of the effect. In particular, they enable a conclusion that the Li nucleates superparamagnetic nanosize spin clusters around the intercalation site which are responsible for the unusual high temperature ferromagnetism of vanadium oxide nanotubes.Comment: with some amendments published in Europhysics Letters (EPL) 88 (2009) 57002; http://epljournal.edpsciences.or

OPPORTUNITIES AND CHALLENGES TO SUSTAINABILITY IN HIDROPONIC SYSTEMS– REVIEW

Hydroponics is a viable solution to obtain intensive agriculture, in terms of producing vegetables and fruits as tasty and nutritious as those produced in classical crops. In the current changing climatic conditions, it can be a viable solution for obtaining high quality food. In addition, the system allows establishment of crops, which do not require the use of soil or manure, but only water that contains various dissolved nutrients. This agricultural cropping technology involves the use of various fertilizers instead of soil for the growth and development of plants. The light needed to develop the plates can come from the sun, or can be produced by renewable energy sources

Energy levels and decoherence properties of single electron and nuclear spins in a defect center in diamond

The coherent behavior of the single electron and single nuclear spins of a defect center in diamond and a 13C nucleus in its vicinity, respectively, are investigated. The energy levels associated with the hyperfine coupling of the electron spin of the defect center to the 13C nuclear spin are analyzed. Methods of magnetic resonance together with optical readout of single defect centers have been applied in order to observe the coherent dynamics of the electron and nuclear spins. Long coherence times, in the order of microseconds for electron spins and tens of microseconds for nuclear spins, recommend the studied system as a good experimental approach for implementing a 2-qubit gate.Comment: 4 pages, 4 figure

Exploration of finite dimensional Kac algebras and lattices of intermediate subfactors of irreducible inclusions

We study the four infinite families KA(n), KB(n), KD(n), KQ(n) of finite dimensional Hopf (in fact Kac) algebras constructed respectively by A. Masuoka and L. Vainerman: isomorphisms, automorphism groups, self-duality, lattices of coideal subalgebras. We reduce the study to KD(n) by proving that the others are isomorphic to KD(n), its dual, or an index 2 subalgebra of KD(2n). We derive many examples of lattices of intermediate subfactors of the inclusions of depth 2 associated to those Kac algebras, as well as the corresponding principal graphs, which is the original motivation. Along the way, we extend some general results on the Galois correspondence for depth 2 inclusions, and develop some tools and algorithms for the study of twisted group algebras and their lattices of coideal subalgebras. This research was driven by heavy computer exploration, whose tools and methodology we further describe.Comment: v1: 84 pages, 13 figures, submitted. v2: 94 pages, 15 figures, added connections with Masuoka's families KA and KB, description of K3 in KD(n), lattices for KD(8) and KD(15). v3: 93 pages, 15 figures, proven lattice for KD(6), misc improvements, accepted for publication in Journal of Algebra and Its Application

Heterocyst placement strategies to maximize growth of cyanobacterial filaments

Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria develop a regular pattern of heterocyst cells that fix nitrogen for the remaining vegetative cells. We examine three different heterocyst placement strategies by quantitatively modelling filament growth while varying both external fixed-nitrogen and leakage from the filament. We find that there is an optimum heterocyst frequency which maximizes the growth rate of the filament; the optimum frequency decreases as the external fixed-nitrogen concentration increases but increases as the leakage increases. In the presence of leakage, filaments implementing a local heterocyst placement strategy grow significantly faster than filaments implementing random heterocyst placement strategies. With no extracellular fixed-nitrogen, consistent with recent experimental studies of Anabaena sp. PCC 7120, the modelled heterocyst spacing distribution using our local heterocyst placement strategy is qualitatively similar to experimentally observed patterns. As external fixed-nitrogen is increased, the spacing distribution for our local placement strategy retains the same shape while the average spacing between heterocysts continuously increases.Comment: This is an author-created, un-copyedited version of an article accepted for publication in Physical Biology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version will be available onlin

RESEARCH REGARDING LABORATORY TESTING OF SOIL PROCESSING EQUIPMENT USING THE EFFECT OF ELECTRO-OSMOSIS

Electro-osmosis principle consists of the application of a direct current voltage for an anode-cathode system introduced into soil. The soil water transported from the anode to cathode, on the tool-soil contact surface will produce a lubrification of an active surface and through this a great decreasing of the friction forces and implicit of the energy needed for displacing the tool through the soil. The active surface of the tilling tool is chosen in order to minimize the frictions, respective the mechanic energies needed for tilling. This paper aims to increase the popularization of the electro-osmosis technique, highlighting the advantages of using such a method for soil improvements, as well as in view of optimizing the functional parameters of the soil tillage equipment