227 research outputs found

    AdvCon, Beacon devices and electronic advertisement

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    Technology is increasingly becoming an important ally for business, so it is important to develop studies and research that bring innovation to the market. This report is about implementation of an app that utilizes a Bluetooth communication as a way of send low data information to a mobile device as an advertisement and how it would help on the business growth. The research that were carried out in order to bring more knowledge about the beacon technology that is being the basis of our project and mobile devices app development. It was found that there is still more to be explored in relation to this technology and much can be done using beacon devices. the technology we seek to implement aims to solve the problem of companies with regard to the lack of visibility of their stores and the possibility of reaching a greater number of customers

    Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions

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    We consider a dynamical brane world in a six-dimensional spacetime containing a singularity. Using the Israel conditions we study the motion of a 4-brane embedded in this setup. We analyse the brane behaviour when its position is perturbed about a fixed point and solve the full nonlinear dynamics in the several possible scenarios. We also investigate the possible gravitational shortcuts and calculate the delay between graviton and photon signals and the ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed to match the version accepted in Class. and Quant. Gra

    Effect of depth and canopy height on the nursery value of Cystoseira balearica forests for Mediterranean rocky reef fishes

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    We studied effects of depth and Cystoseira balearica forests canopy height on coastal juvenile fish assemblages of Minorca Island. Results showed a clear differentiation of juvenile fish assemblages due to depth: assemblage in the shallowest range (3-4m) was characterized by higher densities of Thalassoma pavo, deeper ones (6-8, 10-12 m) by higher densities of Coris julis. Smallest juveniles of both species were more abundant within forests displaying the highest canopy height; meanwhile largest juveniles were more abundant within low Cystoseira forests. Also, both species showed predominantly a cryptic behavior on forest of higher canopy height, and a temporal one when canopy was lower. This study supports the importance of preserving healthy Cystoseira forests in order to preserve their nursery value for these two Labrid species0,000

    Absorption cross section in Lifshitz black hole

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    We derive the absorption cross section of a minimally coupled scalar in the Lifshitz black hole obtained from the new massive gravity. The absorption cross section reduces to the horizon area in the low energy and massless limit of s-wave mode propagation, indicating that the Lifshitz black hole also satisfies the universality of low energy absorption cross section for black holes.Comment: 13 pages, 1 figure, version to appear in EPJ

    Geodesics, the Equivalence Principle and Singularities in Higher-dimensional General Relativity and Braneworlds

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    The geodesics of a spacetime seldom coincide with those of an embedded submanifold of codimension one. We investigate this issue for higher-dimensional general relativity-like models, firstly in the simpler case without branes to isolate which features are already present, and then in the more complicated case with branes. The framework in which we consider branes is general enough to include asymmetric braneworlds but not thick branes. We apply our results on geodesics to study both the equivalence principle and cosmological singularities. Among the models we study these considerations favour Z2Z_2 symmetric braneworlds with a negative bulk cosmological constant.Comment: 20 pages, 2 figures. Accepted by JCAP. Minor proofreading corrections; several references adde

    X-ray absorption tomography employing a conical shell beam

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    We demonstrate depth-resolved absorption imaging by scanning an object through a conical shell of X-rays. We measure ring shaped projections and apply tomosynthesis to extract optical sections at different axial focal plane positions. Three-dimensional objects have been imaged to validate our theoretical treatment. The novel principle of our method is scalable with respect to both scan size and X-ray energy. A driver for this work is to complement previously reported methods concerning the measurement of diffracted X-rays for structural analysis. The prospect of employing conical shell beams to combine both absorption and diffraction modalities would provide enhanced analytical utility and has many potential applications in security screening, process control and diagnostic imaging

    Prisoners in Their Habitat? Generalist Dispersal by Habitat Specialists: A Case Study in Southern Water Vole (Arvicola sapidus)

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    Habitat specialists inhabiting scarce and scattered habitat patches pose interesting questions related to dispersal such as how specialized terrestrial mammals do to colonize distant patches crossing hostile matrices. We assess dispersal patterns of the southern water vole (Arvicola sapidus), a habitat specialist whose habitat patches are distributed through less than 2% of the study area (overall 600 km2) and whose populations form a dynamic metapopulational network. We predict that individuals will require a high ability to move through the inhospitable matrix in order to avoid genetic and demographic isolations. Genotypes (N = 142) for 10 microsatellites and sequences of the whole mitochondrial Control Region (N = 47) from seven localities revealed a weak but significant genetic structure partially explained by geographic distance. None of the landscape models had a significant effect on genetic structure over that of the Euclidean distance alone and no evidence for efficient barriers to dispersal was found. Contemporary gene flow was not severely limited for A. sapidus as shown by high migration rates estimates (>10%) between non-neighbouring areas. Sex-biased dispersal tests did not support differences in dispersal rates, as shown by similar average axial parent-offspring distances, in close agreement with capture-mark-recapture estimates. As predicted, our results do not support any preferences of the species for specific landscape attributes on their dispersal pathways. Here, we combine field and molecular data to illustrate how a habitat specialist mammal might disperse like a habitat generalist, acquiring specific long-distance dispersal strategies as an adaptation to patchy, naturally fragmented, heterogeneous and unstable habitats

    Interferon-Gamma Release Assays Differentiate Between Mycobacterium avium Complex and Tuberculous Lymphadenitis in Children

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    OBJECTIVES: To assess the performance of interferon-gamma release assays (IGRAs) in the differential diagnosis between Mycobacterium avium complex (MAC) and tuberculosis (TB) in children affected with subacute/chronic submandibular/cervical lymphadenitis. STUDY DESIGN: Multicenter observational study comparing children with microbiologically-confirmed MAC lymphadenitis from the European NontuberculouS MycoBacterial Lymphadenitis in childrEn (ENSeMBLE) study with children with TB lymphadenitis from the Spanish Network for the Study of Pediatric TB (pTBred) database. RESULTS: Overall, 78 patients with MAC and 34 with TB lymphadenitis were included. Among MAC cases, 44/74 (59.5%) had positive tuberculin skin test (TST) results at the 5 mm cutoff, compared with 32/33 (97%) TB cases (p<0.001); at the 10 mm cutoff TST results were positive in 23/74 (31.1%) vs. 26/31 (83.9%), respectively (P < .001). IGRA results were positive in only 1/32 (3.1%) MAC cases who had undergone IGRA testing, compared with 21/23 (91.3%) TB cases (p<0.001). Agreement between TST and IGRA results was poor in MAC (23.3%;κ=0.017), but good in TB cases (95.6%;κ=0.646). IGRAs had a specificity of 96.9% (95%CI:84.3-99.8%), positive predictive value (PPV) of 95.4% (95%CI:78.2-99.8%), and negative predictive value (NPV) of 93.9% (95%CI:80.4-98.9%) for TB lymphadenitis. CONCLUSIONS: In contrast to TST, IGRAs have high specificity, NPV and PPV for TB lymphadenitis in children with subacute/chronic lymphadenopathy, and consequently can help to discriminate between TB and MAC disease. Therefore, IGRAs are useful tools in the diagnostic work-up of children with lymphadenopathy, particularly when culture- and PCR-results are negative

    Bi-galileon theory II: phenomenology

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    We continue to introduce bi-galileon theory, the generalisation of the single galileon model introduced by Nicolis et al. The theory contains two coupled scalar fields and is described by a Lagrangian that is invariant under Galilean shifts in those fields. This paper is the second of two, and focuses on the phenomenology of the theory. We are particularly interesting in models that admit solutions that are asymptotically self accelerating or asymptotically self tuning. In contrast to the single galileon theories, we find examples of self accelerating models that are simultaneously free from ghosts, tachyons and tadpoles, able to pass solar system constraints through Vainshtein screening, and do not suffer from problems with superluminality, Cerenkov emission or strong coupling. We also find self tuning models and discuss how Weinberg's no go theorem is evaded by breaking Poincar\'e invariance in the scalar sector. Whereas the galileon description is valid all the way down to solar system scales for the self-accelerating models, unfortunately the same cannot be said for self tuning models owing to the scalars backreacting strongly on to the geometry
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