Congestion-gradient driven transport on complex networks

We present a study of transport on complex networks with routing based on local information. Particles hop from one node of the network to another according to a set of routing rules with different degrees of congestion awareness, ranging from random diffusion to rigid congestion-gradient driven flow. Each node can be either source or destination for particles and all nodes have the same routing capacity, which are features of ad-hoc wireless networks. It is shown that the transport capacity increases when a small amount of congestion awareness is present in the routing rules, and that it then decreases as the routing rules become too rigid when the flow becomes strictly congestion-gradient driven. Therefore, an optimum value of the congestion awareness exists in the routing rules. It is also shown that, in the limit of a large number of nodes, networks using routing based on local information jam at any nonzero load. Finally, we study the correlation between congestion at node level and a betweenness centrality measure.Comment: 11 pages, 8 figure

Optimal routing on complex networks

We present a novel heuristic algorithm for routing optimization on complex networks. Previously proposed routing optimization algorithms aim at avoiding or reducing link overload. Our algorithm balances traffic on a network by minimizing the maximum node betweenness with as little path lengthening as possible, thus being useful in cases when networks are jamming due to queuing overload. By using the resulting routing table, a network can sustain significantly higher traffic without jamming than in the case of traditional shortest path routing.Comment: 4 pages, 5 figure

Transport optimization on complex networks

We present a comparative study of the application of a recently introduced heuristic algorithm to the optimization of transport on three major types of complex networks. The algorithm balances network traffic iteratively by minimizing the maximum node betweenness with as little path lengthening as possible. We show that by using this optimal routing, a network can sustain significantly higher traffic without jamming than in the case of shortest path routing. A formula is proved that allows quick computation of the average number of hops along the path and of the average travel times once the betweennesses of the nodes are computed. Using this formula, we show that routing optimization preserves the small-world character exhibited by networks under shortest path routing, and that it significantly reduces the average travel time on congested networks with only a negligible increase in the average travel time at low loads. Finally, we study the correlation between the weights of the links in the case of optimal routing and the betweennesses of the nodes connected by them.Comment: 19 pages, 7 figure

AXES at TRECVID 2012: KIS, INS, and MED

The AXES project participated in the interactive instance search task (INS), the known-item search task (KIS), and the multimedia event detection task (MED) for TRECVid 2012. As in our TRECVid 2011 system, we used nearly identical search systems and user interfaces for both INS and KIS. Our interactive INS and KIS systems focused this year on using classifiers trained at query time with positive examples collected from external search engines. Participants in our KIS experiments were media professionals from the BBC; our INS experiments were carried out by students and researchers at Dublin City University. We performed comparatively well in both experiments. Our best KIS run found 13 of the 25 topics, and our best INS runs outperformed all other submitted runs in terms of P@100. For MED, the system presented was based on a minimal number of low-level descriptors, which we chose to be as large as computationally feasible. These descriptors are aggregated to produce high-dimensional video-level signatures, which are used to train a set of linear classifiers. Our MED system achieved the second-best score of all submitted runs in the main track, and best score in the ad-hoc track, suggesting that a simple system based on state-of-the-art low-level descriptors can give relatively high performance. This paper describes in detail our KIS, INS, and MED systems and the results and findings of our experiments

PLASMA MEMBRANE REDOX SYSTEM IN THE ERYTHROCYTES OF ROWERS: PILOT STUDY

Background: The oxidative stress results from a change in the physiological balance between oxidant and antioxidant species. The purpose of this study is twofold: first, to investigate the effects of long-term training in sports with high energy requirements on the redox balance which exists between the plasma vs. the erythrocytes; second, to study the activity of the PMRS (Plasma Membrane Redox System), which is a compensatory mechanism of cellular redox homeostasis, in the rowers’ erythrocytes in order to determine the rowers’ counteraction to oxidative stress. Methods: Venous blood samples was collected from rowers and control group; then FRAP (Ferric Reducing Activity Power) method has been used to determine the antioxidant capabilities both in the plasma and in the erythrocytes of 22 rowers vs. 26 sedentary subjects. For the same groups of subjects, the PMRS in erythrocytes has been also evaluated. Results: The plasmatic antioxidant activity was 21% lower in the group of rowers compared to the sedentary group (p = 0,02). In contrast, no significant differences were found in the reducing activity of the erythrocytes; however the erythrocytes of the rowers have shown values of the PMRS 35% higher than the untrained group (p < 0.0001). Conclusions: Rowing induces a significant oxidative stress in the plasma corresponding to the high intensity training, while this effect lacks in erythrocytes. At the same time an increased quantity of the PMRS has been observed in the erythrocytes. In conclusion, in well trained athletes this not lead to established an oxidative stress condition because long-term training adaptatively improves the efficiency of the antioxidant syste

Intestinal microbiota mutualism and gastrointestinal diseases

The purpose of this work is to investigate the link between an altered intestinal mcro-biota or dysbiosis and chronic inflammatory disorders, in particular inflammatory bowel disease (IBD). Along with probiotics, faecal microbiota transplantation (FMT) opts to be a promising therapeutic treatment for restoring the bacterial homeostasis of the hu-man intestine and reducing the risk of colorectal carcinogenesis. Microbiota is the com-plex microbial flora that resides in the gut establishing a mutually beneficial relation-ship. Alteration of the microbiota’s composition, termed as dysbiosis, may lead to pathological conditions. Treatment with probiotics can restore the normal commensal flora in IBD. Intestinal microbiota affects the circadian rhythm which in turn regulates the expression of different genes in GALT (gut associated lymphoid tissue) playing a role in the prevention of inflammation and colorectal cancer (CRC) progression. This article highlights the involvement of different microbial strains in the pathogenesis of dysbiosis and in the creation of a carcinogenic milieu caused by an altered stimulation of the immune system. Therapies targeting the equilibrium of the microbiota to switch off chronic inflammation and prevent the progression to CRC seem to be a promising therapeutic tool for a variety of inflammation-associated diseases

Distributed flow optimization and cascading effects in weighted complex networks

We investigate the effect of a specific edge weighting scheme $\sim (k_i k_j)^{\beta}$ on distributed flow efficiency and robustness to cascading failures in scale-free networks. In particular, we analyze a simple, yet fundamental distributed flow model: current flow in random resistor networks. By the tuning of control parameter $\beta$ and by considering two general cases of relative node processing capabilities as well as the effect of bandwidth, we show the dependence of transport efficiency upon the correlations between the topology and weights. By studying the severity of cascades for different control parameter $\beta$, we find that network resilience to cascading overloads and network throughput is optimal for the same value of $\beta$ over the range of node capacities and available bandwidth

Optimal transport on wireless networks

We present a study of the application of a variant of a recently introduced heuristic algorithm for the optimization of transport routes on complex networks to the problem of finding the optimal routes of communication between nodes on wireless networks. Our algorithm iteratively balances network traffic by minimizing the maximum node betweenness on the network. The variant we consider specifically accounts for the broadcast restrictions imposed by wireless communication by using a different betweenness measure. We compare the performance of our algorithm to two other known algorithms and find that our algorithm achieves the highest transport capacity both for minimum node degree geometric networks, which are directed geometric networks that model wireless communication networks, and for configuration model networks that are uncorrelated scale-free networks.Comment: 5 pages, 4 figure

Application of artificial neural networks for determining the temperature and partial pressures of the components of high-temperature gaseous media

The paper deals with the development of methods for solving the inverse problem of gaseous media optics by determining the parameters of high-temperature gaseous media from its spectral characteristics. It is proposed to use artificial neural networks to determine the temperature and partial pressures of water vapor, carbon dioxide, carbon oxide and nitrogen oxide from its transmissivities

Origin and distribution of the ischiatic nerves in goats of the Saanen breed

Estudaram-se a origem e distribuição dos nervos isquiáticos, de ambos os antímeros, em 30 caprinos (Capra hircus) da raça Saanen, sendo 16 machos e 14 fêmeas. Estes animais foram coletados após morte natural e submetidos à fixação em solução aquosa, a 10%, de formaldeído. Os nervos isquiáticos originaram-se 28 vezes (93,3%) do ramo ventral do sexto nervo espinhal lombar e dos ramos ventrais do primeiro e segundo nervos espinhais sacrais; além disso, esses nervos tabém receberam duas vezes (6,7%), contribuição do ramo ventral do terceiro nervo espinhal sacral. Os nervos isquiáticos cederam, em todos os animais, ramos para os músculos glúteos médios, glúteos profundos, gluteobíceps, gêmeos, semitendíneos e semimembranáceos. Sobretudo, notaram-se arranjos peculiares desses ramos musculares para cada espécime. Através da aplicação da prova de Wilcoxon, com nível de significância de 0,05, não se observaram diferenças significativas entre as freqüências de ramos musculares dos nervos isquiáticos, que foram cedidos para os antímeros direito e esquerdo, e ainda em relação ao sexo dos caprinos da presente investigação.The origin and distribution of the ischiatic nerves at both sides were studied in 30 goats (Capra hircus) of the Saanen breed, being 16 males and 14 females. These specimens were collected after natural death of the animals and submitted to fixation in a 10% formaldehyde solution. The ischiatic nerves arose from the ventral branch of the sixth lumbar and the first and second sacral spinal nerves in 28 cases (93.3%). In addition, these nerves also received contributions from the ventral branch of the third sacral spinal nerve in two cases (6.7%) at both sides. In all animals, the right and left ischiatic nerves gave off branches to the muscles gluteus medius, gluteus profundus, gluteobiceps, gemelli, semitendinosus, and semimembranosus muscles. In particular, peculiar arrangements of these muscular branches were noticed for each specimen. By using the Wilcoxon test with significance level at 0.05, there were no significant differences among the frequencies of muscular branches of the ischiatic nerves emitted to the right and left sides, and also in relation to the sex of the goats in the present investigation