1,924 research outputs found

    Is job insecurity a driver of the housing cycle? Some evidence in the spanish case

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    The aim of this paper is to study a possible connection between the characteristics of the labour market, namely, employment protection and flexibility, and the dynamics of the housing market. More specifically, this contribution analyses whether the poor quality of employment in a given economy could cause the collapse of the housing market and impairs its recovery. In the second stage of our analysis, we provide estimates for Spain over the period 1984-2014. In doing so, the autoregressive distributed lag (ARDL) bounds test for cointegration is employed.This is the author accepted manuscript. The final version is available from The Association of Economists of Vojvodina via http://dx.doi.org/10.2298/PAN1501001

    A Computation in a Cellular Automaton Collider Rule 110

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    A cellular automaton collider is a finite state machine build of rings of one-dimensional cellular automata. We show how a computation can be performed on the collider by exploiting interactions between gliders (particles, localisations). The constructions proposed are based on universality of elementary cellular automaton rule 110, cyclic tag systems, supercolliders, and computing on rings.Comment: 39 pages, 32 figures, 3 table

    Marine sponge as a source of antiangiogenic compounds. The case of aeroplysinin-1

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    The vast majority of the natural compounds that have been previously described as inhibitors of angiogenesis have been isolated from plants and terrestrial microorganisms, mainly due to their higher availability and because their therapeutic effects had been previously known in folk traditional medicines. However, increasing attention is being paid to the development of marine-derived antiangiogenic agents, probably fuelled by the increase in the number of marine-derived anticancer drugs which are being successfully used for cancer therapy. Marine organisms, adapted to survive in extreme environments by developing chemical means of defence, produce interesting and singular pharmacological lead compounds, derived from the large diversity of marine habitats and environmental conditions. Among the many different types of marine organisms used as a source for drug discovery, sponges represent one of the most promising sources of leads in the research of new cancer drugs. Some angiogenesis inhibitors isolated from marine sponges have been described by us and others. Aeroplysinin-1, a brominated metabolite extracted from the marine sponge Aplysina aerophoba, has been characterized by our group as a potent antiangiogenic compound in vitro and in vivo. Aeroplysinin-1 induces apoptosis in endothelial cells by a mechanism which involves activation of the BH3-only pro-apoptotic protein Bad, cytochrome c release and activation of caspases 2, 3, 8 and 9, what indicates a relevant role of the mitochondria in the apoptogenic activity of this compound. Recent results suggest that aeroplysinin-1 could also be a novel potential anti-inflammatory compound. These results open new ways to the potential pharmacological action of aeroplysinin-1 not only on angiogenesis and cancer, but also on atherosclerosis and inflammation-dependent diseases.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Natural ventilation for the prevention of airborne contagion.

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    BACKGROUND: Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. METHODS AND FINDINGS: The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. CONCLUSIONS: Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion

    Prime power indices in factorised groups

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    [EN] Let the group G = AB be the product of the subgroups A and B. We determine some structural properties of G when the p-elements in A. B have prime power indices in G, for some prime p. More generally, we also consider the case that all prime power order elements in A. B have prime power indices in G. In particular, when G = A = B, we obtain as a consequence some known results.The first author is supported by Proyecto Prometeo II/2015/011, Generalitat Valenciana (Spain), and the second author is supported by Proyecto MTM2014-54707-C3-1-P, Ministerio de Economia, Industria y Competitividad (Spain). The results in this paper are part of the third author's Ph.D. thesis, and he acknowledges the predoctoral grant ACIF/2016/170, Generalitat Valenciana (Spain).Felipe Román, MJ.; Martínez-Pastor, A.; Ortiz-Sotomayor, VM. (2017). Prime power indices in factorised groups. Mediterranean Journal of Mathematics. 14(6):1-15. https://doi.org/10.1007/s00009-017-1023-6S115146Amberg, B., Franciosi, S., de Giovanni, F.: Products of Groups. Oxford University Press Inc., New York (1992)Baer, R.: Group elements of prime power index. Trans. Am. Math. Soc. 75, 20–47 (1953)Ballester-Bolinches, A., Cossey, J., Li, Y.: Mutually permutable products and conjugacy classes. Monatsh. Math. 170, 305–310 (2013)Ballester-Bolinches, A., Esteban-Romero, R., Asaad, M.: Products of finite groups, vol. 53 of de Gruyter Expositions in Mathematics, Berlin (2010)Berkovich, Y., Kazarin, L.S.: Indices of elements and normal structure of finite groups. J. Algebra 283, 564–583 (2005)Camina, A.R., Camina, R.D.: Implications of conjugacy class size. J. Group Theory 1(3), 257–269 (1998)Camina, A.R., Shumyatsky, P., Sica, C.: On elements of prime-power index in finite groups. J. Algebra 323, 522–525 (2010)Chillag, D., Herzog, M.: On the length of the conjugacy classes of finite groups. J. Algebra 131, 110–125 (1990)Doerk, K., Hawkes, T.: Finite Soluble Groups, vol. 4 of de Gruyter Expositions in Mathematics, Berlin (1992)Felipe, M.J., Martínez-Pastor, A., Ortiz-Sotomayor, V.M.: On finite groups with square-free conjugacy class sizes. Int. J. Group Theory (to appear)Kurzweil, H., Stellmacher, B.: The theory of finite groups: an introduction. Springer, New York (2004)Liu, X., Wang, Y., Wei, H.: Notes on the length of conjugacy classes of finite groups. J. Pure Appl. Algebra 196, 111–117 (2005

    nSharma: Numerical Simulation Heterogeneity Aware Runtime Manager for OpenFOAM

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    CFD simulations are a fundamental engineering application,implying huge workloads, often with dynamic behaviour due to run-time mesh refinement. Parallel processing over heterogeneous distributedmemory clusters is often used to process such workloads. The executionof dynamic workloads over a set of heterogeneous resources leads to loadimbalances that severely impacts execution time, when static uniformload distribution is used. This paper proposes applying dynamic, het-erogeneity aware, load balancing techniques within CFD simulations.nSharma, a software package that fully integrates with OpenFOAM, ispresented and assessed. Performance gains are demonstrated, achievedby reducing busy times standard deviation among resources, i.e. hetero-geneous computing resources are kept busy with useful work due to aneffective workload distribution. To best of authors’ knowledge, nSharmais the first implementation and integration of heterogeneity aware loadbalancing in OpenFOAM and will be made publicly available in order tofoster its adoption by the large community of OpenFOAM users.The authors would like to thank the financial funding by FEDER through the COMPETE 2020 Program, the National Funds through FCT under the projects UID/CTM/50025/2013. The first author was partially funded by the PT-FLAD Chair on Smart Cities & Smart Governance and also by the School of Engineering, University of Minho within project Performance Portability on Scalable Heterogeneous Computing Systems. The authors also wish to thank Kyle Mooney for making available his code supporting migration of dynamically refined meshes, as well as acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources

    Exploring pig trade patterns to inform the design of risk-based disease surveillance and control strategies

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    An understanding of the patterns of animal contact networks provides essential information for the design of risk-based animal disease surveillance and control strategies. This study characterises pig movements throughout England and Wales between 2009 and 2013 with a view to characterising spatial and temporal patterns, network topology and trade communities. Data were extracted from the Animal and Plant Health Agency (APHA)’s RADAR (Rapid Analysis and Detection of Animal-related Risks) database, and analysed using descriptive and network approaches. A total of 61,937,855 pigs were moved through 872,493 movements of batches in England and Wales during the 5-year study period. Results show that the network exhibited scale-free and small-world topologies, indicating the potential for diseases to quickly spread within the pig industry. The findings also provide suggestions for how risk-based surveillance strategies could be optimised in the country by taking account of highly connected holdings, geographical regions and time periods with the greatest number of movements and pigs moved, as these are likely to be at higher risk for disease introduction. This study is also the first attempt to identify trade communities in the country, information which could be used to facilitate the pig trade and maintain disease-free status across the country in the event of an outbreak

    Biomass dust explosions: CFD simulations and venting experiments in a 1 m3 silo

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    This study presents CFD simulations of biomass dust explosions in a newly developed experimental 1 m3 silo apparatus with variable venting, designed and fabricated to operate similarly to the explosivity test standards. The aim of the study is to validate a CFD model under development and investigate its capability to capture the transient effects of a vented explosion. The model is based on OpenFOAM and solves the multiphase (gas-particle) flow using an Eulerian-Lagrangian approach in a two-way regime. It considers the detailed thermochemical conversion of biomass, including moisture evaporation, devolatilization, and char oxidation, along with the homogeneous combustion of gases, turbulence, and radiative heat transfer. The explosion is analyzed in all stages, i.e., dust cloud dispersion, ignition, closed explosion, and vented explosion. The results indicate excellent agreement between the CFD model and experimental tests throughout the sequence. Our findings highlight the critical role of particle size in dust cloud distribution and pre-ignition turbulence, which significantly influences flame dynamics and the explosion itself. This model shows great promise and encourages its application for future investigations of biomass dust explosions in larger-scale geometries, especially in venting situations that fall out of the scope of the NFPA 68 or EN 14491 standards, and to help design effective safety measures to prevent such incidents
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