2,639 research outputs found
Experimental assessment of RRM techniques in 5 GHz dense WiFi networks using REMs
“© 2018 IEEE. Personal use of this material is permitted. Permission
from IEEE must be obtained for all other uses, in any current or future
media, including reprinting/republishing this material for advertising or
promotional purposes, creating new collective works, for resale or
redistribution to servers or lists, or reuse of any copyrighted
component of this work in other works.”The increasing acceptance of WiFi has created
unprecedented levels of congestion in the unlicensed frequency
bands, especially in densely populated areas. This results mainly
because of the unmanaged interference and uncoordinated op-
eration between WiFi access points. Radio Environment Maps
(REM) have been suggested as a support for coordination
strategies that optimize the overall WiFi network performance.
In this context, the main objective of this experiment is to assess
the benefit of a coordinated management of radio resources in
dense WiFi networks at 5 GHz band, using REMs for indoor
scenarios. It was shown that REMs can detect the presence of
interfering links on the network or coverage holes, and a suitable
coordination strategy can use this information to reconfigure
Access Points (AP) channel assignment and re-establish the client
connection, at a cost of diminishing the aggregate throughput
of the network. The technique of AP hand-off was tested to
balance the load from one AP to another. Using REMs, the Radio
Resource Management (RRM) strategy could reconfigure the
network to optimize the client distribution among available APs.
Although the aggregate throughput is lower after load balancing,
the RRM could increase the throughput of the overloaded AP.info:eu-repo/semantics/publishedVersio
A phase of transient subsidence, sediment bypass and deposition of regressive-transgressive cycles during the breakup of Iberia and Newfoundland
Seismic, outcrop and well data from West Iberia and Newfoundland are used to investigate sediment stacking patterns during continental breakup as a function of tectonic subsidence. In West Iberia, two breakup sequences are revealed on seismic data by marked strata offlap oceanwards from the present-day continental shelf. This character is similar to Newfoundland, where correlative strata comprise Lower Cretaceous–Cenomanian coarse-grained siliciclastics accumulated around local sediment-source areas. The interpreted data reveal that the two breakup sequences: 1) materialise sediment bypass onto continental-slope depocentres that experienced important tectonic subsidence during continental breakup, but without showing typical syn-rift growth packages; 2) generate specific forced-regressive stratigraphic intervals that relate to uplift and exhumation of the proximal margin. Subsidence and sediment stacking patterns in both West Iberia and Newfoundland reflect similar continental breakup processes as they evolved from the upper lithosphere- to their mantle-breakup stages. On both margins, coarse-grained siliciclastic units on the proximal margin give rise to thick shaley successions in deep-water basins. This work also confirms that in a setting dominated by a significant sediment influx, yet lacking the burial rates of continental slope basins in Newfoundland, West Iberia comprised accommodation-driven basins during continental breakup, not necessarily sediment starved. As a corollary of our analysis, we classify breakup sequences around the world based on the characteristic lithologies of their regressive–transgressive depositional cycles
On the origins of scaling corrections in ballistic growth models
We study the ballistic deposition and the grain deposition models on
two-dimensional substrates. Using the Kardar-Parisi-Zhang (KPZ) ansatz for
height fluctuations, we show that the main contribution to the intrinsic width,
which causes strong corrections to the scaling, comes from the fluctuations in
the height increments along deposition events. Accounting for this correction
in the scaling analysis, we obtained scaling exponents in excellent agreement
with the KPZ class. We also propose a method to suppress these corrections,
which consists in divide the surface in bins of size and use only
the maximal height inside each bin to do the statistics. Again, scaling
exponents in remarkable agreement with the KPZ class were found. The binning
method allowed the accurate determination of the height distributions of the
ballistic models in both growth and steady state regimes, providing the
universal underlying fluctuations foreseen for KPZ class in 2+1 dimensions. Our
results provide complete and conclusive evidences that the ballistic model
belongs to the KPZ universality class in dimensions. Potential
applications of the methods developed here, in both numerics and experiments,
are discussed.Comment: 8 pages, 7 figure
Ability of Gordonia alkanivorans strain 1B for high added value carotenoids production
Currently, carotenoids are valuable bioactive molecules for several industries, such as chemical, pharmaceutical, food and cosmetics, due to their multiple benefits as natural colorants, antioxidants and vitamin precursors. Hence, the increasing interest on these high added-value products has led to the search of alternatives, more cost-effective and with better yields, towards their industrial production. Indeed, microbial metabolism offers a promising option for carotenoids production. Herein it is shown the potential of the dibenzothiophene desulfurizing bacterium Gordonia alkanivorans strain 1B as a high carotenoid-producer microorganism. The novel carotenoids, produced under different culture conditions, were extracted with DMSO and then further analyzed both through spectrophotometry and HPLC. When grown in glucose-sulfate-light, strain 1B was able of achieving 2015 g carotenoids per g DCW in shake-flask assays, with about 60% corresponding to lutein, canthaxanthin and astaxanthin. Further optimization studies open a new focus
of research aiming to get a hyper pigment-producer strain that may be applied towards different industrial sectors
Using Value Nets to Map Emerging Business Models in Massively Multiplayer Online Games
The authors map some of the current Business Models in the Massively Multiplayer Online Player scenario. These maps represent Value Creation Systems by resorting to Value Net constructs and notations, and are offered here as a proof of concept and utility. The authors claim that these mappings can enable “readers”, managers and IT experts, to build new insights onto such Business Models and develop requirements for Information System infrastructure. When approaching the Value Creation System as a Value Net the goal is to think outside the conceptual box of Value Chains and understand how the different activities interact, by exposing the multiplicity of value types and flows. In doing this study the authors are attempting to synthesize a new Business Model proposal that could underlie the development of an infrastructure for the collaborative creation, distribution and exploration of online massively multiplayer games, beyond the traditional producer-consumer roles
Using CRISPR-Cas9 technology to create Danio rerio dnah7 mutants
CRISPR-Cas9 is a recent discovered genetic editing mechanism, that shows a lot of versatility. This allows scientists to do genetic manipulation with relative ease when compared with others current genetic tools available. One possible application of the CRISPR-Cas9 system is to mimic human disease mutations by targeting orthologous genes in animal models, which allows a better characterization of the mechanisms behind a particular disease.
Cilia are hair-like structures that protrude from the cell surface in organisms and can be classified as motile or non-motile. They are responsible for several important functions throughout the human body. Such functions include, generating fluid flow and sensing mechanical or chemical cues from the surrounding environment. If these are compromised it can lead to ciliopathies. Ciliopathies are a group of diseases and syndromic diseases characterized by malfunctioning of cilia. Motile cilia can lead to a disease known as primary ciliary dyskinesia (PCD). More than 35 genes have been linked with cilia motility in PCD patients. Some of these genes are associated with the inner dynein arms present in the axoneme. A better understanding of mutations in these genes would help the characterization of PCD.
Using CRISPR-Cas9 we tried to cause a mutation in dnah7, a gene that encodes a protein present in inner dynein arms. Two SgRNAs were selected to disrupt dnah7 and injected into zebrafish embryos. These F0 embryos were screened for mutations outcrossed and left to sexually mature. When matured, the progeny was screened again to find any heritable mutations. Meanwhile, analyses of cilia beat frequency and pattern, the readouts of cilia function, were made in a set of wild type and ccdc40 MO injected zebrafish. Additionally, two SgRNAs were designed for targeting another PCD commonly mutated gene named rsph4a, a gene coding for a protein present in the radial spokes of the axonemes
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