Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number

A study on the spatial organization and velocity fluctuations of non Brownian spherical particles settling at low Reynolds number in a vertical Hele-Shaw cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while the distance between cell plates ranged from 5 to 15 times the particle radius. Particle tracking revealed that particles were not uniformly distributed in space but assembled in transient settling clusters. The population distribution of these clusters followed an exponential law. The measured velocity fluctuations are in agreement with that predicted theoretically for spherical clusters, from the balance between the apparent weight and the drag force. This result suggests that particle clustering, more than a spatial distribution of particles derived from random and independent events, is at the origin of the velocity fluctuations.Comment: 13 pages, 8 figure

Self-management of context-aware overlay ambient networks

Ambient Networks (ANs) are dynamically changing and heterogeneous as they consist of potentially large numbers of independent, heterogeneous mobile nodes, with spontaneous topologies that can logically interact with each other to share a common control space, known as the Ambient Control Space. ANs are also flexible i.e. they can compose and decompose dynamically and automatically, for supporting the deployment of cross-domain (new) services. Thus, the AN architecture must be sophisticatedly designed to support such high level of dynamicity, heterogeneity and flexibility. We advocate the use of service specific overlay networks in ANs, that are created on-demand according to specific service requirements, to deliver, and to automatically adapt services to the dynamically changing user and network context. This paper presents a self-management approach to create, configure, adapt, contextualise, and finally teardown service specific overlay networks

Energy Efficiency of Hybrid-Power HetNets: A Population-like Games Approach

In this paper, a distributed control scheme based on population games is proposed. The controller is in charge of dealing with the energy consumption problem in a Heterogeneous Cellular Network (HetNet) powered by hybrid energy sources (grid and renewable energy) while guaranteeing appropriate quality of service (QoS) level at the same time. Unlike the conventional approach in population games, it considers both atomicity and non-anonymity. Simulation results show that the proposed population-games approach reduces grid consumption by up to about 12% compared to the traditional best-signal level association policy.U.S. Air Force Office of Scientific Research FA9550-17-1-0259Ministerio de Cultura y Deporte DPI2016-76493-C3-3-RMinisterio de Economía y Empresa DPI2017-86918-

Marine sponges of the genus neopetrosia with anti-inflammatory activity

The present study aimed to investigate the anti-inflammatory effect of marine sponges of the genus Neopetrosia which are abundant in the Colombian Caribbean. We obtained three fractions from a total methanolic extract of Neopetrosia rosariensis and proxima. In vivo activity was measured using λ-carrageenan-induced paw edema assay. The in vitro inhibitory effects were evaluated on myeloperoxidase activity (MPO) and nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor alpha (TNF- α) production. Total extracts of N. rosariensis and N. proxima (100 mg/Kg) significantly inhibited the paw edema of rats (71.74% and 60.06%, respectively). Dichloromethane and methanol fractions of Neopetrosia sponges reduced MPO activity. Only, dichloromethane fraction of N. rosariensis significantly inhibited NO (66%), PGE2 (30.5%) and TNF-α production (72%). Our results show anti-inflammatory activity in extracts and fractions from species of marine sponges belonging to Neopetrosia genus and open the way for complementary studies to purify and identify active molecules.Colegio de Farmacéuticos de la Provincia de Buenos Aire

A well defined glass state obtained by oscillatory shear

We investigate the process of shear melting and re-solidification of a colloidal glass, directly after loading (pre-yielding) and after a series of consecutive strain sweeps (post-yielding). The post-yielding glass shows a significant softening compared to the pre-yielding glass, together with the absence of history effects in successive shear melting protocols, indicating a reproducible process of fluidisation and re-solidification into a glass state unaffected by residual stresses. However, a significant hysteresis characterises strain sweeps with increasing or decreasing strain amplitude. The appearance of history and hysteresis effects coincides with the formation of a glass state, whereas it is not observed in the liquid. We can describe the onset of shear melting over a broad range of volume fractions and frequencies using a recently developed model which describes the yielding process in terms of loss of long-lived nearest neighbours

Differential Gene Expression from Midguts of Refractory and Susceptible Lines of the Mosquito, Aedes aegypti, Infected with Dengue-2 Virus

Suppressive subtractive hybridization was used to evaluate the differential expression of midgut genes of feral populations of Aedes aegypti (Diptera: Culicidae) from Colombia that are naturally refractory or susceptible to Dengue-2 virus infection. A total of 165 differentially expressed sequence tags (ESTs) were identified in the subtracted libraries. The analysis showed a higher number of differentially expressed genes in the susceptible Ae. aegypti individuals than the refractory mosquitoes. The functional annotation of ESTs revealed a broad response in the susceptible library that included immune molecules, metabolic molecules and transcription factors. In the refractory strain, there was the presence of a trypsin inhibitor gene, which could play a role in the infection. These results serve as a template for more detailed studies aiming to characterize the genetic components of refractoriness, which in turn can be used to devise new approaches to combat transmission of dengue fever

Caracterización epidemiológica, clínica y virológica de los nuevos diagnósticos de infección por VHC en Galicia (2014-2015)

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Finance, foreign (direct) investment, and the Dutch disease: the case of Colombia

In recent years Colombia has grown relatively rapidly, but it has been a biased growth. The energy sector (the locomotora minero-energetica, to use the rhetorical expression of President Juan Manuel Santos) grew much faster than the rest of the economy, while the manufacturing sector registered a negative rate of growth. These are classic symptoms of the well-known ‘Dutch disease’, but our purpose here is not to establish whether the Dutch disease exists or not, but rather to shed some light on the financial viability of several, simultaneous dynamics: (i) the existence of a traditional Dutch Disease being due to a large increase in mining exports and a significant exchange rate appreciation; (ii) a massive increase in foreign direct investment (FDI), particularly in the mining sector; (iii) a rather passive monetary policy, aimed at increasing purchasing power via exchange rate appreciation; (iv) more recently, a large distribution of dividends from Colombia to the rest of the world and the accumulation of mounting financial liabilities. The paper will show that these dynamics constitute a potential danger for the stability of the Colombian economy. Some policy recommendations are also discussed

Differential antibody response against conformational and linear epitopes of the L1 protein from human papillomavirus types 16/18 is generated in vaccinated woman or with different exposures to the virus

Antibodies against human papillomavirus (HPV) L1 protein are associated to past infections and related to the evolution of the disease, while antibodies against L1 virus like particles (VLPs-L1) are used to follow the neutralizing immune response in vaccinated women. In this study, sera antibodies against conformational and linear epitopes of L1 protein from HPV16/18 were evaluated to discriminate HPV vaccinated women from those naturally infected or with uterine cervical lesions. The VLPs-L1 from HPV16/18 generated in baculovirus were purified by CsCl gradient and linear L1 protein obtained by denature VLPs. Serum antibodies against VLPs-L1 and L1 from vaccinated women or with different exposures to the virus were measured by ELISA. Regresion and ROC analysis were carried out to evaluete the test performance to discriminate the different women populations. The results showed that antibodies against VLPs-L1-16/18 highly associated with vaccinated women (OR=2.11e+08 and 57.74, respectively), but not associations were observed with natural infected women or with cervical lesions. However, antibodies against L1-16/18 showed high associations with vaccinated women (OR= 101.33 and 37.91, respectively) (p≤ 0.05), but also associations of these antibodies were observed with the cervical cancer (CC) group (OR= 3.33 and 5.65, respectively). The ROC analysis showed that antibodies against VLPs-L1 and L1 16/18 were highly effective to detect vaccinated women (AUC= 0.96, 0.91. 0.80 and 0.78, respectively), with high sensitivity for HPV16 (100% and 86.3%), and moderate for HPV18 (63.6%). However, anti-L1 antibodies had the best test performance to discriminate the cervical intraepithelial neoplasia grade 3 (CIN3)/CC group from controls (AUC= 0.67 HPV16 and 0.63 HPV18), with low sensitivity (15% to 20%, respectively) and high specificity (96% and 92%, respectively). In conclusion, our results suggested that anti-VLPs-L1 16/18 antibodies are highly efficient to detect vaccinated women, but anti-L1 antibodies are better to discriminate CIN3/CC among the general population