1,147 research outputs found

    Resource design in constrained networks for network lifetime increase

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    As constrained "things" become increasingly integrated with the Internet and accessible for interactive communication, energy efficient ways to collect, aggregate, and share data over such constrained networks are needed. In this paper, we propose the use of constrained RESTful environments interfaces to build resource collections having a network lifetime increase in mind. More specifically, based on existing atomic resources, collections are created/designed to become available as new resources, which can be observed. Such resource design should not only match client's interests, but also increase network lifetime as much as possible. For this to happen, energy consumption should be balanced/fair among nodes so that node depletion is delayed. When compared with previous approaches, results show that energy efficiency and network lifetime can be increased while reducing control/registration messages, which are used to set up or change observations

    The decays h+- -> W-+ h0(a0) within an extension of the MSSM with one complex Higgs triplet

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    The vertex H+-W-+h0, involving the gauge bosons W-+, the charged (H+-) and the lightest neutral (h0) Higgs bosons, arises within the context of many extensions of the SM, and it can be used to probe the Higgs sector of such extensions via the decay H+- -> W+- h0. We discuss the strength of this vertex for an extension of the MSSM with an additional complex Higgs triplet. By using this model, we find regions of the parameter space where the decay H+- -> W+- h0 is not only kinematically allowed, but it also becomes an important decay mode and in some cases the dominant one.Comment: 10 figure

    Financialisation and the portuguese private consumption: two contradictory effects?

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    This paper makes an empirical evaluation of the relationship between financialisation and the Portuguese private consumption by performing a time series econometric analysis from the first quarter of 1996 to the last quarter of 2016. Framed within the post-Keynesian literature, financialisation has two contradictory effects on private consumption. The first one corresponds to the fall in the households’ labour income, which favours a deceleration of private consumption. The second one corresponds to the increase of households’ financial and housing wealth, which favours an acceleration of private consumption. The global net effect of financialisation tends to be positive because the beneficial wealth effect suppresses the harmful income effect. We estimated a private consumption equation that includes four control variables (unemployment rate, inflation rate, short-term interest rate and long-term interest rate) and three variables linked to financialisation (labour income, financial wealth and housing wealth). Our results confirm that labour income, financial wealth and housing wealth are positive determinants of Portuguese private consumption. Our results also show that financialisation has represented an important driver of Portuguese private consumption, particularly due to the beneficial effects of financial wealth.FC

    Determinants of the Portuguese government bond yields

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    This paper conducts an empirical examination of the determinants of the 10‐, 5‐ and 1‐year Portuguese government bond yields by performing a time series econometric analysis for the period between the first quarter of 2000 and the last quarter of 2016. The literature suggests that the evolution of government bond yields depends on three main risk drivers, namely credit risk, global risk aversion and liquidity risk. We estimate three equations for the 10‐, 5‐ and 1‐year Portuguese government bond yields, including eight independent variables (macroeconomic performance, fiscal conditions, foreign borrowing, the inflation rate, labour productivity, the demographic situation, global risk aversion and liquidity risk) to take into account all three risk drivers referred to in the literature. Our results show that there are no significant differences in the determinants of the Portuguese government bond yields among the different maturities, either in the long term or in the short term. Our results also confirm that all three of the risk drivers have exerted a strong influence on the evolution of the Portuguese government bond yields. Liquidity risk, foreign borrowing and the inflation rate are the main triggers of the rise in the Portuguese government bond yields, which does not counterweigh the beneficial effects played by the fiscal conditions, labour productivity and demographic situation.info:eu-repo/semantics/acceptedVersio

    Combining technologies to create bioactive hybrid scaffolds for bone tissue engineering

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    Combining technologies to engineer scaffolds that can offer physical and chemical cues to cells is an attractive approach in tissue engineering and regenerative medicine. In this study, we have fabricated polymer-ceramic hybrid scaffolds for bone regeneration by combining rapid prototyping (RP), electrospinning (ESP) and a biomimetic coating method in order to provide mechanical support and a physico-chemical environment mimicking both the organic and inorganic phases of bone extracellular matrix (ECM). Poly(ethylene oxide terephthalate)-poly(buthylene terephthalate) (PEOT/PBT) block copolymer was used to produce three dimensional scaffolds by combining 3D fiber (3DF) deposition, and ESP, and these constructs were then coated with a Ca-P layer in a simulated physiological solution. Scaffold morphology and composition were studied using scanning electron microscopy (SEM) coupled to energy dispersive X-ray analyzer (EDX) and Fourier Tranform Infrared Spectroscopy (FTIR). Bone marrow derived human mesenchymal stromal cells (hMSCs) were cultured on coated and uncoated 3DF and 3DF + ESP scaffolds for up to 21 d in basic and mineralization medium and cell attachment, proliferation, and expression of genes related to osteogenesis were assessed. Cells attached, proliferated and secreted ECM on all the scaffolds. There were no significant differences in metabolic activity among the different groups on days 7 and 21. Coated 3DF scaffolds showed a significantly higher DNA amount in basic medium at 21 d compared with the coated 3DF + ESP scaffolds, whereas in mineralization medium, the presence of coating in 3DF+ESP scaffolds led to a significant decrease in the amount of DNA. An effect of combining different scaffolding technologies and material types on expression of a number of osteogenic markers (cbfa1, BMP-2, OP, OC and ON) was observed, suggesting the potential use of this approach in bone tissue engineerin

    Neoplasia renal con extensión a la vena cava

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    La neoplasia renal con extensión a la vena cava es relativamente rara (4-10%). Cualquiera que sea la terapia coadjuvante (radioterapia, hormonal, quimioterapia e inmunoterapia), la exéresis completa del trombo tumoral de la vena cava continúa siendo la mejor forma de tratamiento. El valor pronóstico de la extensión cefálica de un trombo tumoral en la vena cava inferior en enfermos con carcinoma de células renales es controvertido. Es posible conseguir una larga supervivencia después del tratamiento quirúrgico en enfermos con carcinoma de células renales localizado (supervivencia de 50% en 5 años). Los autores describen un caso de carcinoma de células renales con extensión a la vena cava en un enfermo del sexo masculino, de 70 años de edad. El enfermo presentaba una historia de lumbalgia derecha y edema del miembro inferior homolateral. La resonancia magnética demostró la presencia y el nivel del trombo tumoral. El enfermo fue sometido a nefrectomía radical derecha y exéresis completa del trombo tumoral de la vena cava. Renal cancer with vena cava tumour thrombus is relatively rare (4 to 10%). Because of the poor results obtained with any kind of alternative therapy (e.g. radiation, hormonal, chemotherapy and immunotherapy) operation with complete removal of the vena cava tumour thrombus continues to be the better method of treatment. The prognostic significance of the cephalic extent of an inferior vena caval tumor thrombus associated with renal cell carcinoma is controversial. Long-term survival after surgical treatment is possible in patients with localized renal cell carcinoma (survival 50% at five years). The authors report a case of vena caval extension of renal cell carcinoma in a 70-years-old man. The patient presented with a history of right lombar pain and pedal edema. Magnetic Ressonance demonstrated the presence and the level of tumoral thrombus. The patient was submitted to a radical nefrectomy and complete removal of tumor thrombus from vena caval

    Towards truly simultaneous PIXE and RBS analysis of layered objects in cultural heritage

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    For a long time, RBS and PIXE techniques have been used in the field of cultural heritage. Although the complementarity of both techniques has long been acknowledged, its full potential has not been yet developed due to the lack of general purpose software tools for analysing the data from both techniques in a coherent way. In this work we provide an example of how the recent addition of PIXE to the set of techniques supported by the DataFurnace code can significantly change this situation. We present a case in which a non homogeneous sample (an oxidized metal from a photographic plate -heliography- made by Niepce in 1827) is analysed using RBS and PIXE in a straightforward and powerful way that can only be performed with a code that treats both techniques simultaneously as a part of one single and coherent analysis. The optimization capabilities of DataFurnace, allowed us to obtain the composition profiles for these samples in a very simple way.Comment: 9 pages, 3 figure

    An energy-aware resource design model for constrained networks

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    The Internet of Things is expected to incorporate objects and sensor networks of all kinds, and in particular, constrained sensor networks where energy consumption is a critical issue. In order to increase the lifetime of such networks, intelligent and standard-based solutions should be used. Here, we address this challenge through the use of CoRE interfaces for the resource design. These interfaces allow the server side to compose/organize resources and the client side to discover and determine how to consume such resources, besides allowing decisions to be easily integrated into the operation of the network. An energy-aware resource design model is proposed, based on CoRE interfaces, for the design of resources matching client needs. Based on this model, we develop an algorithm that proved to be energy efficient

    GACN: Self-clustering genetic algorithm for constrained networks

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    Extending the lifespan of a wireless sensor network is a complex problem that involves several factors, ranging from device hardware capacity (batteries, processing capabilities, and radio efficiency) to the chosen software stack, which is often unaccounted for by the previous approaches. This letter proposes a genetic algorithm-based clustering optimization method for constrained networks that significantly improves the previous state-of-the-art results, while accounting for the specificities of the Internet engineering task force, Constrained RESTful Environment (CoRE), standards for data transmission and specifically relying on CoRE interfaces, which fit this purpose very well.info:eu-repo/semantics/publishedVersio
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