18 resultados para Small World Graphs
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
Real-world graphs or networks tend to exhibit a well-known set of properties, such as heavy-tailed degree distributions, clustering and community formation. Much effort has been directed into creating realistic and tractable models for unlabelled graphs, which has yielded insights into graph structure and evolution. Recently, attention has moved to creating models for labelled graphs: many real-world graphs are labelled with both discrete and numeric attributes. In this paper, we present AGWAN (Attribute Graphs: Weighted and Numeric), a generative model for random graphs with discrete labels and weighted edges. The model is easily generalised to edges labelled with an arbitrary number of numeric attributes. We include algorithms for fitting the parameters of the AGWAN model to real-world graphs and for generating random graphs from the model. Using the Enron “who communicates with whom” social graph, we compare our approach to state-of-the-art random labelled graph generators and draw conclusions about the contribution of discrete vertex labels and edge weights to the structure of real-world graphs.
Resumo:
Real-world graphs or networks tend to exhibit a well-known set of properties, such as heavy-tailed degree distributions, clustering and community formation. Much effort has been directed into creating realistic and tractable models for unlabelled graphs, which has yielded insights into graph structure and evolution. Recently, attention has moved to creating models for labelled graphs: many real-world graphs are labelled with both discrete and numeric attributes. In this paper, we presentAgwan (Attribute Graphs: Weighted and Numeric), a generative model for random graphs with discrete labels and weighted edges. The model is easily generalised to edges labelled with an arbitrary number of numeric attributes. We include algorithms for fitting the parameters of the Agwanmodel to real-world graphs and for generating random graphs from the model. Using real-world directed and undirected graphs as input, we compare our approach to state-of-the-art random labelled graph generators and draw conclusions about the contribution of discrete vertex labels and edge weights to graph structure.
Resumo:
While investigations using covert food manipulations tend to suggest that individuals are poor at adjusting for previous energy intake, in the real world adults rarely consume foods of which they are ill-informed. This study investigated the impact in fully complicit consumers of consuming commercially available dark chocolate, milk chocolate, sweet biscuits and fruit bars on subsequent appetite. Using a repeated measures design, participants received four small portions (4 × 10-11 g) of either dark chocolate, milk chocolate, sweet biscuits, fruit bars or no food throughout five separate study days (counterbalanced in order), and test meal intake, hunger, liking and acceptability were measured. Participants consumed significantly less at lunch following dark chocolate, milk chocolate and sweet biscuits compared to no food (smallest t(19) = 2.47, p = 0.02), demonstrating very good energy compensation (269-334%). No effects were found for fruit bars (t(19) = 1.76, p = 0.09), in evening meal intakes (F(4,72) = 0.62, p = 0.65) or in total intake (lunch + evening meal + food portions) (F(4,72) = 0.40, p = 0.69). No differences between conditions were found in measures of hunger (largest F(4,76) = 1.26, p = 0.29), but fruit bars were significantly less familiar than all other foods (smallest t(19) = 3.14, p = 0.01). These findings demonstrate good compensation over the short term for small portions of familiar foods in complicit consumers. Findings are most plausibly explained as a result of participant awareness and cognitions, although the nature of these cognitions cannot be discerned from this study. These findings however, also suggest that covert manipulations may have limited transfer to real world scenarios.
Resumo:
Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin i <2.4 km s-1. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be , the radius to be 1.066 ± 0.012 Ro, and the age to be Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R⊕. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M⊕. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 MJ in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 MJ. The 12 exoplanets with radii ⊕ and precise mass measurements appear to fall into two populations, with those ⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm-3, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.
Resumo:
Since the introduction of molecular computation1, 2, experimental molecular computational elements have grown3, 4, 5 to encompass small-scale integration6, arithmetic7 and games8, among others. However, the need for a practical application has been pressing. Here we present molecular computational identification (MCID), a demonstration that molecular logic and computation can be applied to a widely relevant issue. Examples of populations that need encoding in the microscopic world are cells in diagnostics or beads in combinatorial chemistry (tags). Taking advantage of the small size9 (about 1 nm) and large 'on/off' output ratios of molecular logic gates and using the great variety of logic types, input chemical combinations, switching thresholds and even gate arrays in addition to colours, we produce unique identifiers for members of populations of small polymer beads (about 100 m) used for synthesis of combinatorial libraries10, 11. Many millions of distinguishable tags become available. This method should be extensible to far smaller objects, with the only requirement being a 'wash and watch' protocol12. Our focus on converting molecular science into technology concerning analog sensors13, 14, turns to digital logic devices in the present work.
Resumo:
Key tenets of modern biology are the central place of protein in cell regulation and the flow of genetic information from DNA to RNA to protein. However, it is becoming increasingly apparent that genomes are much more complex than hitherto thought with remarkably complex regulatory systems. The notion that the fraction of the genome involved in coding protein is all that matters is increasingly being questioned as the roles of non-coding RNA (ncRNA) in cellular systems becomes recognised. The RNA world, including microRNA (miRNA), small inhibitory RNA (siRNA) and other RNA species, are now recognised as being crucial for the regulation of chromatin structure, gene expression, mRNA processing and splicing, mRNA stability and translational control. Furthermore such ncRNA systems may be perturbed in disease states and most notably in neoplasia, including in haematological malignancies. Here the burgeoning evidence for a role of miRNA in neoplasia is reviewed and the importance of understanding the RNA world emphasised. Copyright (c) 2005 John Wiley & Sons, Ltd.
Resumo:
This publication takes the form of a written version of my inaugural lecture, which was presented at Queen’s University Belfast on 10 March 2010. It is more personal and considerably more self-indulgent than would normally be acceptable in an article, with more of my own experiences and also my own references than would usually be considered proper. However, the bestowal of such a title as Professor of Island Geography is something of a marker of the maturity not just of myself but maybe also for island studies. After a section describing my path into island geography, the lecture deals with the negativities of islands and the seeming futility of studying them only then to identify a new or at least enhanced regard for islands as places with which to interact and to examine. Reference is made to islands throughout the world, but with some focus on the small islands off Ireland. The development of island studies as a discipline is then briefly described before the lecture concludes with reference to its title quotation on St Helena by considering that place’s islandness and how this affected/affects it in both the 17th and 21st centuries.
Resumo:
The MaRINET project aims to build a synergy in the European marine renewable energy development infrastructure network, involving a total of 28 partners across the union. Its scope extends from small to large scale testing, in both tank and field. The main activities of the project are to standardize test procedures, to provide centralized free access for European technology developers, and to innovate for improving test infrastructures and techniques.
This paper presents the work carried in this last part, which focuses on research objectives identified to be current challenges for industrial development. They are distributed in 6 topics. On the one hand are issues that concern directly one of the 3 types of energy scoped in the project: wave, tidal, and offshore wind energy. Two examples are the real time estimation of incident waves, and the measurement of turbulence in tidal flows. On the other hand, collaborative effort is drawn on aspects that are common to those technologies: electrical components, environmental monitoring, and dedicated moorings.
Resumo:
Global development has, in recent years, been shaped by the rise of transnational capital. This has implications for the quality and effectiveness of those national laws, regulations and policies in place to monitor transnational capital, ensure that multi national organisations assume responsibility and hold them accountable should they fail to do so. In balancing these objectives, contrasting issues come to the fore, such as the fear of capital flight; an issue especially profound in small open economies where the balance may tip in the favour of retaining, as opposed to regulating, foreign capital.
This paper can be considered in three parts. First, the paper addresses the shift in global leadership from national governments to multinational corporations (with particular reference to the rise of the Transnational Capitalist Class). This shift will incorporate the connotations of the Third Way. In considering this ideology, it will propose the Third Way as a transition phase to a stage when government is more the “third wheel” than an equal partner in governance structures. Second, the implications of the changing nature of governance on the capacity of nation states to develop effective laws, regulations and policies is discussed which leads on to the third aspect of the paper which identifies the challenges for governments, business and society in reimagining the governance structure pertaining to law, regulation and policy and the need to reconsider existing structures in light of global shifts in power structures.
A new leadership structure, both within the national and international governance system has far reaching implications. Boundary constraints no longer an issue, the potential for equality and global democracy is huge. Instead, a post recessionary world faces new governance challenges in the shape of; legitimacy; accountability and responsibility. Capitalism has invaded government and the primary challenge will be in avoiding the same issues that have dogged our financial markets for the last number of years. The challenge then to laws, regulations and public policy is huge, especially considering that the governments regulating are smaller than those dictating agenda on a global level
Resumo:
Germany experienced a devastating period during the First World War due to severely restricted import possibilities and a general shortage of foodstuffs. This study uses the heights of some 4,000 individuals who served during the Second World War to quantify biological living standards from the 1900s to the 1920s, and focuses primarily on socioeconomic inequality during this period. The results suggest that generally the upper social strata, measured by fathers' occupation, exhibited the tallest average height, followed by the middle and lower classes. These socioeconomic differences became more pronounced during the First World War when the rationing system provided a limited food supply. Wealthier individuals were able to purchase additional foodstuffs on black markets. Therefore, children from upper-class families experienced only a small decline in average height compared to their counterparts from the middle and lower social strata.