Cost-efficient wireless mobile backhaul topologies: an analytical study

Proceedings of: 2010 IEEE Global Telecommunications Conference (GLOBECOM 2010), 6-10 December 2010, Miami, Florida, USAWireless communication technologies such as microwave radios are used to provide high-speed mobile backhaul connectivity for radio access networks in cases in which wirebased alternatives, e.g. cable or fiber, are not readily available and cannot be deployed in an economic or timely manner. Current mobile backhauls are predominantly deployed in tree or ring topologies, which simplify traffic management. Yet, with the increasing demand on backhaul capacity and the immense cost pressure on mobile backhaul solutions, meshed wireless mobile backhauls have been identified as a promising evolution. While traffic management in wireless mesh networks have been studied extensively in the literature, so far there is no quantitative analysis comparing the different topology options, i.e. mesh, ring and tree, regarding network performance and deployment cost. This paper fills this gap by studying the minimum cost problem of connecting a set of base station/gateway sites using different topologies while supporting both time- and space-varying traffic demands. Furthermore, we consider the additional constraint of resilience to single link failures. The evaluation results show that meshed wireless backhaul topologies are a cost-effective alternative to trees and rings, in particular in the face of spatial and temporal fluctuation of traffic demand and protection against link failuresEuropean Community's Seventh Framework ProgramPublicad

Fibromuscular dysplasia presenting as a renal infarction: a case report

<p>Abstract</p> <p>Introduction</p> <p>Fibromuscular dysplasia is a non-atherosclerotic, non-inflammatory disease that most commonly affects the renal and internal carotid arteries.</p> <p>Case presentation</p> <p>We present the case of a 44-year-old Caucasian man who was admitted with complaints of loin pain and hypertension. A computed tomography scan of the abdomen revealed a right renal infarction with a nodular aspect of the right renal artery. Subsequent renal angiography revealed a typical 'string of beads' pattern of the right renal artery with thrombus formation. Oral anticoagulation was started and the secondary hypertension was easily controlled with anti-hypertensive drugs. At follow-up, our patient refused percutaneous transluminal renal angioplasty as a definitive treatment.</p> <p>Conclusions</p> <p>Fibromuscular dysplasia is the most common cause of renovascular hypertension in patients under 50 years of age. Presentation with renal infarction is rare.</p> <p>In fibromuscular dysplasia, angioplasty has been proven to have, at least for some indications, an advantage over anti-hypertensive drugs. Therefore, hypertension secondary to fibromuscular dysplasia is the most common cause of curable hypertension.</p

Chasing Migration Genes: A Brain Expressed Sequence Tag Resource for Summer and Migratory Monarch Butterflies (Danaus plexippus)

North American monarch butterflies (Danaus plexippus) undergo a spectacular fall migration. In contrast to summer butterflies, migrants are juvenile hormone (JH) deficient, which leads to reproductive diapause and increased longevity. Migrants also utilize time-compensated sun compass orientation to help them navigate to their overwintering grounds. Here, we describe a brain expressed sequence tag (EST) resource to identify genes involved in migratory behaviors. A brain EST library was constructed from summer and migrating butterflies. Of 9,484 unique sequences, 6068 had positive hits with the non-redundant protein database; the EST database likely represents ∼52% of the gene-encoding potential of the monarch genome. The brain transcriptome was cataloged using Gene Ontology and compared to Drosophila. Monarch genes were well represented, including those implicated in behavior. Three genes involved in increased JH activity (allatotropin, juvenile hormone acid methyltransfersase, and takeout) were upregulated in summer butterflies, compared to migrants. The locomotion-relevant turtle gene was marginally upregulated in migrants, while the foraging and single-minded genes were not differentially regulated. Many of the genes important for the monarch circadian clock mechanism (involved in sun compass orientation) were in the EST resource, including the newly identified cryptochrome 2. The EST database also revealed a novel Na+/K+ ATPase allele predicted to be more resistant to the toxic effects of milkweed than that reported previously. Potential genetic markers were identified from 3,486 EST contigs and included 1599 double-hit single nucleotide polymorphisms (SNPs) and 98 microsatellite polymorphisms. These data provide a template of the brain transcriptome for the monarch butterfly. Our “snap-shot” analysis of the differential regulation of candidate genes between summer and migratory butterflies suggests that unbiased, comprehensive transcriptional profiling will inform the molecular basis of migration. The identified SNPs and microsatellite polymorphisms can be used as genetic markers to address questions of population and subspecies structure

Effect of insulin on meiosis reinitiation induced in vitro by three progestogens in oocytes of the goldfish (Carassius auratus)

Three progestogens were tested for their ability to elicit meiosis reinitiation as evidenced by germinal vesicle dissolution (GVD) in goldfish (Carassius auratus) follicle-enclosed oocytes in vitro. In two independent experiments 17α-20β-dihydroxyprogesterone (DHP) was most active followed in turn by 17α-hydroxyprogesterone (HP) and progesterone (P). Values of the effective dose for a 50% response for GVD induced by P and HP were significantly reduced by the addition of Na-insulin, however, insulin had no significant effect on DHP incubates. Meiotogenic activity was potentiated by Na-insulin in the following heirarchy: P \u3e HP \u3e DHP. These results indicate that insulin, which had little meiotogenic activity alone, was capable of differentially enhancing progestogen activity in this system. The mechanism by which Na-insulin augments progestogen GVD-inducing activity is unknown, but may include decrease of progestogen degradation, increase in progestogen biosynthesis, and direct insulin effects on the oocyte. The results suggest that insulin may play a physiological role in goldfish oocyte meiosis reinitiation by enhancing the activity of certain progestogens, which by themselves are not potent meiotogens. © 1985

Fecundity and spawning periodicity in wild-type zebrafish mated pairs: A long-term, longitudinal study

In order to gain insight into the reproductive cycle of the zebrafish, Danio rerio, 70 mated pairs of wild-type adults were followed daily for spawning over a month, on average, and in some cases for more than four months. Different sets of mated pairs were followed over a 5 year period and each spawn was imaged by transparency scanner and quantified by image analysis using imageJ software. The 70 pairs produced a total of 37,711 embryos in 952 spawns over the course of 2,727 spawn-days. This gave an average spawning periodicity of 2.86 days and an average clutch size of 39.6 embryos. Considerable variation in spawning periodicity and clutch size occurred, in spite of constant environmental and nutritional conditions. Some mated pairs were consistently short periodicity spawners, while others exhibited intermediate or long periodicity. Spawning periodicity did not correlate well with clutch size, i.e., long periodicity spawning pairs were not necessarily producing larger clutch sizes. These data provide a foundation for study of the reproductive cycle of the zebrafish, an increasingly important model system

Oocyte maturation: Converting the zebrafish oocyte to the fertilizable egg

The process of oogenesis culminates in steroid-induced oocyte maturation to produce the fertilizable egg. A quintessential biological entity, the egg is central to the production of new individuals. The result of egg fertilization by a sperm cell is the production of the mother of all stem cells (i.e. the zygote). Furthermore, the egg cytoplasm is the only one known to support reprogramming a transplanted nucleus to give rise to an individual (i.e. animal cloning). Zebrafish oocyte maturation is a complex event encompassing a number of cellular changes including germinal vesicle migration (GVM) and dissolution or breakdown (GVD), ooplasmic clearing (OC) with correlated yolk protein changes (YP), development of osmoregulation (OR) in fresh water, the formation of the future embryonic pole, the blastodisc (BF) and activatibility (AC) or cortical maturation. In zebrafish, and many other teleosts, 17α, 20β-dihydroxy-4-pregnen-3-one (17α, 20β-DP) has been shown to be the normal inducer of oocyte maturation. A 17α, 20β-DP membrane-resident receptor mediates oocyte maturation via non-genomic mechanisms that are beginning to be understood. This paper will highlight some of the cellular markers resulting from the signaling initiated by 17α, 20β-DP. By describing these markers, it is hoped that workers in the field will have additional tools to help further elucidate the signaling events of oocyte maturation. © 2008 Elsevier Inc. All rights reserved