3,708 research outputs found
A conceptual model and rapid appraisal tool for integrated coastal floodplain assessments
No full textLow-lying coastal zones are high-risk areas threatened by flooding due to extreme coastal events and rising sea-levels. The coastal floodplain system includes elements such as near-shore waves and water levels, inter-tidal beaches and coastal habitats, natural and artificial sea defences and multiple inland floodplain features. Flood risk studies generally achieve an integrated assessment of these elements using multiple numerical models for different floodplain elements. However fundamental choices of floodplain description and the appropriate data, methods and models can vary widely between different sites and flood risk studies. A comprehensive conceptual model is needed to describe the floodplain system and help inform these choices in each site. However a descriptive conceptual model for coastal floodplain systems does not exist at present. There is a bias in flood risk studies towards the direct use of numerical models with limited use of conceptual models – existing models are implicit and do not describe the coastal floodplain system.This thesis addresses this gap by developing, applying and testing a rapid appraisal tool that conceptually describes the coastal floodplain as a system of interacting elements. The tool is developed in two parts – i) a quasi-2D Source– Pathway – Receptor (SPR) model that provides a comprehensive qualitative description of the floodplain; and ii) a Bayesian network model that uses this description to quantify individual elements as sources, pathways and receptors of flood propagation. The quasi-2D SPR is applied in 8 diverse coastal zones across Europe 4 of which include nested case-studies. It is an effective way of gathering and describing information about the floodplain from stakeholders across multiple disciplines. The Bayesian network model is applied to two contrasting floodplain systems in England – Teignmouth and Portsmouth. The network model is effective in pinpointing critical flood pathways and identifying key knowledge gaps for further analyses. The two models together provide a comprehensive understanding of the coastal floodplain system that can be used to inform and target the use of more detailed numerical models.Hence this thesis provides a conceptual model and tool to improve flood risk assessment. It makes conceptual understanding of the floodplain explicit and stratifies quantitative analysis by application of a rapid assessment tool before the use of detailed numerical models
A Critical Study of the Autobiographical Elements in the Fictional Works of R. K. Narayan
No full textNot availabl
Investigating the source – pathway – receptor – consequence framework for coastal flood system analyses
No full textAre Shocks to Commodity Prices Persistent?
No full textThis paper considers the issue of whether shocks to ten commodity prices (gold, silver, platinum, copper, aluminum, iron ore, lead, nickel, tin, and zinc) are persistent or transitory. We use two recently developed unit root tests, namely the Narayan and Popp (NP, 2010) test and the Liu and Narayan (LN, 2010) test that allow for two structural breaks in the data series. Using the NP test, we are able to reject the unit root null for iron ore and tin, while, using the GARCH-based unit root test of LN, we are able to reject the unit root null for five commodity prices; namely, iron ore, nickel, zinc, lead, and tin. Our findings, thus, suggest that only shocks to gold, silver, platinum, aluminum, and copper are persistent.Commodity Prices; Unit Root Test; GARCH.
Computational Complexity of Graph Partition under Vertex-Compaction to an Irreflexive Hexagon
No full textIn this paper, we solve a long-standing graph partition problem under vertex-compaction that has been of interest since about 1999. The graph partition problem that we consider in this paper is to decide whether or not it is possible to partition the vertices of a graph into six distinct non-empty sets A, B, C, D, E, and F, such that the vertices in each set are independent, i.e., there is no edge within any set, and an edge is possible but not necessary only between the pairs of sets A and B, B and C, C and D, D and E, E and F, and F and A, and there is no edge between any other pair of sets. We study the problem as the vertex-compaction problem for an irreflexive hexagon (6-cycle). Determining the computational complexity of this problem has been a long-standing problem of interest since about 1999, especially after the results of open problems obtained by the author on a related compaction problem appeared in 1999. We show in this paper that the vertex-compaction problem for an irreflexive hexagon is NP-complete. Our proof can be extended for larger even irreflexive cycles, showing that the vertex-compaction problem for an irreflexive even k-cycle is NP-complete, for all even k \geq 6
Thermodynamic balancing of the humidification dehumidification desalination system by mass extraction and injection
No full textHumidification dehumidification (HDH) is a promising technology for small scale seawater desalination and has received widespread attention in recent years. The biggest roadblock to commercialization of this technology is its relatively high energy consumption. In this paper, we propose thermodynamic balancing of the humidifier or the dehumidifier through mass extraction and injection as a potential means of reducing the energy consumption of these systems. Balancing minimizes the entropy generation caused by imbalance in driving temperature and concentration differences. We outline a procedure to model the system, using on-design component variables, such that continuous or discrete extraction and-or injection of air from the humidifier to the dehumidifier or vice versa can be analyzed. We present an extraction profile (mass flow rate ratio versus non-dimensional position) in the dehumidifier and the humidifier for attaining close to complete thermodynamic reversibility in an HDH system with a 100percent effective humidifier and dehumidifier. Further, we have examined in detail the effect of having finite-sized systems, of balancing the humidifier versus the dehumidifier, and that of the number of extractions. © 2012 Elsevier Ltd. All rights reserved.Bejan A., 1996, ENTROPY GENERATION M; Bourouni K., 2001, DESALINATION, V137; Brendel T., 2003, THESIS RUHR U BOCHUM; Brendel T., 2003, German Patent, Patent No. [#DE10215079 (A1), 10215079]; Grune W., 1961, M AM SOC MECH ENG NE; Hou S., 2008, DESALINATION, V222, P5728; Hyland R.W., 1983, ASHRAE T, V89-IIa, P520; Lemmon E.W., 2007, STANDARD REFERENCE D; McGovern R.K., APPL ENERGY IN PRESS; Miller J.A., 2011, THESIS MIT; Mistry KH, 2011, INT J THERM SCI, V50, P779, DOI 10.1016-j.ijthermalsci.2010.12.013; Muller-Holst H, 2007, NATO SCI PEACE SECUR, P215, DOI 10.1007-978-1-4020-5508-9_16; Muller-Holst H., 2002, THESIS TU BERLIN; Narayan G. P., 2012, THESIS MIT; Narayan G. P., 2011, P ASME JSME 8 THERM; Narayan GP, 2010, DESALIN WATER TREAT, V16, P339, DOI 10.5004-dwt.2010.1078; Narayan G.P., 2010, FRONTIERS HEAT MASS, V1, P1; Narayan GP, 2010, RENEW SUST ENERG REV, V14, P1187, DOI 10.1016-j.rser.2009.11.014; Narayan GP, 2012, ENERGY, V37, P482, DOI 10.1016-j.energy.2011.11.007; Narayan GP, 2010, INT J THERM SCI, V49, P2057, DOI 10.1016-j.ijthermalsci.2010.04.024; Schlickum T., 2007, European Patent, Patent No. [EP 1770068 A2, 1770068]; Shah R.K., 2003, FUNDAMENTALS HEAT EX; Sharqawy MH, 2010, DESALIN WATER TREAT, V16, P354, DOI 10.5004-dwt.2010.1079; Thiel GP, 2012, INT J HEAT MASS TRAN, V55, P5133, DOI 10.1016-j.ijheatmasstransfer.2012.05.014; Wagner W, 2002, J PHYS CHEM REF DATA, V31, P387, DOI 10.1063-1.1461829; Wessel D.J., 2001, ASHRAE FUNDAMENTALS, V2001; YOUNIS MA, 1993, DESALINATION, V94, P11, DOI 10.1016-0011-9164(93)80151-C; Zamen M, 2011, CHEM ENGINEER TRANS, V25, P1091, DOI 10.3303-CET1125182118
To what extent are Bangladesh's recent gains in poverty reduction different from the past?
No full textThe poor in Bangladesh are more likely to belong to households with a larger number of dependents and lower education among household members, be engaged in daily wage labor, own little land, and be less likely to receive remittances. This poverty profile for 2005 is similar to the profile in the mid-1980s and hence at first glance it would appear that little has changed over time. A closer look at national household survey data suggests a more nuanced story. This paper uses the latest two rounds of the Bangladesh Household Income and Expenditure Survey to decompose the micro-determinants of poverty reduction between 2000 and 2005, closely following a similar analysis using five earlier rounds of the Survey. The comparison of results shows that the spatial distribution of poverty seen in earlier decades has changed with time and the drivers of poverty reduction are different in several respects.Rural Poverty Reduction,Regional Economic Development,Access to Finance,Small Area Estimation Poverty Mapping
PICALM Rescues Endocytic Defects Caused by the Alzheimer's Disease Risk Factor APOE4
No full textAPOE4 is the strongest genetic risk factor for late-onset Alzheimer's disease (AD). Narayan and Sienski et al. find that APOE4 disrupts early endocytosis, a process by which cells take up external material. By increasing the levels of another AD risk factor, PICALM, the authors are able to reverse these disruptions
The digital journey: 25 years of digital development in electrophysiology from an Europace perspective
No full textAims: Over the past 25 years there has been a substantial development in the field of digital electrophysiology (EP) and in parallel a substantial increase in publications on digital cardiology. In this celebratory paper, we provide an overview of the digital field by highlighting publications from the field focusing on the EP Europace journal. Results: In this journey across the past quarter of a century we follow the development of digital tools commonly used in the clinic spanning from the initiation of digital clinics through the early days of telemonitoring, to wearables, mobile applications, and the use of fully virtual clinics. We then provide a chronicle of the field of artificial intelligence, a regulatory perspective, and at the end of our journey provide a future outlook for digital EP. Conclusion: Over the past 25 years Europace has published a substantial number of papers on digital EP, with a marked expansion in digital publications in recent years.Emma Svennberg, Enrico G. Caiani, Nico Bruining, Lien Desteghe, Janet K. Han, Sanjiv M. Narayan, Frank E. Rademakers, Prashanthan Sanders and David Duncke
A Role of the Inflammasome in the Low Storage Capacity of the Abdominal Subcutaneous Adipose Tissue in Obese Adolescents
No full textThe innate immune cell sensor leucine-rich-containing family, pyrin domain containing 3 (NLRP3) inflammasome controls the activation of caspase-1, and the release of proinflammatory cytokines interleukin (IL)-1b and IL-18. The NLRP3 inflammasome is implicated in adipose tissue inflammation and the pathogenesis of insulin resistance. Herein, we tested the hypothesis that adipose tissue inflammation and NLRP3 inflammasome are linked to the downregulation of subcutaneous adipose tissue (SAT) adipogenesis/lipogenesis in obese adolescents with altered abdominal fat partitioning. We performed abdominal SAT biopsies on 58 obese adolescents and grouped them by MRI-derived visceral fat to visceral adipose tissue (VAT) plus SAT (VAT/VAT+SAT) ratio (cutoff 0.11). Adolescents with a high VAT/VAT+SAT ratio showed higher SAT macrophage infiltration and higher expression of the NLRP3 inflammasome-related genes (i.e., TLR4, NLRP3, IL1B, and CASP1). The increase in inflammation markers was paralleled by a decrease in genes related to insulin sensitivity (ADIPOQ, GLUT4, PPARG2, and SIRT1) and lipogenesis (SREBP1c, ACC, LPL, and FASN). Furthermore, SAT ceramide concentrations correlated with the expression of CASP1 and IL1B. Infiltration of macrophages and upregulation of the NLRP3 inflammasome together with the associated high ceramide content in the plasma and SAT of obese adolescents with a high VAT/VAT+SAT may contribute to the limited expansion of the subcutaneous abdominal adipose depot and the development of insulin resistance
- …
