Fluctuation-dissipation relation and the Edwards entropy for a glassy granular compaction model

We analytically study a one dimensional compaction model in the glassy regime. Both correlation and response functions are calculated exactly in the evolving dense and low tapping strength limit, where the density relaxes in a $1/\ln t$ fashion. The response and correlation functions turn out to be connected through a non-equilibrium generalisation of the fluctuation-dissipation theorem. The initial response in the average density to an increase in the tapping strength is shown to be negative, while on longer timescales it is shown to be positive. On short time scales the fluctuation-dissipation theorem governs the relation between correlation and response, and we show that such a relationship also exists for the slow degrees of freedom, albeit with a different temperature. The model is further studied within the statistical theory proposed by Edwards and co-workers, and the Edwards entropy is calculated in the large system limit. The fluctuations described by this approach turn out to match the fluctuations as calculated through the dynamical consideration. We believe this to be the first time these ideas have been analytically confirmed in a non-mean-field model.Comment: 4 pages, 3 figure

Modelling Provenance of Sensor Data for Food Safety Compliance Checking

The research described here was funded by an award made by the RCUK IT as a Utility Network+ (EP/K003569/1) and the UK Food Standards Agency. We thank the owner and staff of Rye & Soda restaurant, Aberdeen for their support throughout the project.Postprin

An organization overview of pedagogical practice in work-integrated education

Tertiary curriculum design has increasingly emphasized work-integrated learning (WIL) opportunities. This qualitative study provides an overview of a variety of WIL activities at Massey University, New Zealand. Descriptive comments, provided through interviews with fifteen academic supervisors from disciplines ranging from the applied sciences through social sciences to business, education and creative arts, highlight the following six factors to be considered in the resourcing of WIL programs. Themes related to set-up include placement requirements, support, selection, location, and risk management issues. Student preparation involves pre-requisite theoretical knowledge, general career preparation (CV & interview skills) and readiness for practice. With respect to supervision, an on-campus academic mentor and a work-place supervisor are both important to the student. Competencies linked to team work and professional standards include self-confidence, communication and people skills. The teaching pedagogies used include lectures and labs, oral presentations, scenario-based-learning and project work. Assessment involved a learning contract, reflective journal, oral presentation, and final report

Cathodoluminescence hyperspectral imaging on the nanometre scale

Extending cathodoluminescence microscopy into the hyperspectral imaging mode brings significant benefits to an already powerful nano-scale characterization tool. In this paper, we give an introduction to the technique, and illustrate its potential with examples of its application to both semiconducting and plasmonic nanostructures

Comment on "Effect of growth interruptions on the light emission and indium clustering of InGaN/GaN multiple quantum wells" [Appl. Phys. Lett. 79, 2594 (2001)]

This entry is a comment on "Effect of growth interruptions on the light emission and indium clustering

Large-scale temporal and spatial patterns of marine phytoplankton in the north-east Atlantic

Phytoplankton constitute the main algal biomass in pelagic ecosystems and, therefore, play a fundamental role in the functioning of the marine trophic web. Information on long-term trends in marine phytoplankton may help to distinguish between biological responses to natural oscillations in climate and global warming, and to evaluate possible regional effects of eutrophication. The aim of this work was to contribute to the general understanding of how phytoplankton are spatio-temporally structured at the large-scale. To achieve this aim, the Continuous Plankton Recorder (CPR) survey data were used to identify the dominant large-scale spatial patterns of phytoplankton in north-western European continental shelf waters. Spatial patterns have been described in relation to their variability in time (seasonal and decadal). Finally, fluctuations of phytoplankton in space and time are described in relation to changes in the environment of the North Atlantic. The analysis included approximately 70,000 samples taken between 1960-1995. The large-scale, spatio-temporal patterns ranged from the meso to the macro-scale (50-10,000 km) and from months to decades. The structure of the thesis follows a progression from the seasonal to the inter-annual scale and from phytoplankton biomass to the phytoplankton community. Particular emphasis is placed on a broad overview of the long-term changes in marine phytoplankton and interpreting anomalous phytoplankton values. Overall, the results suggest that the environment plays a fundamental role in structuring the phytoplankton from the seasonal scale to the decadal scale. The seasonal spatial evolution of phytoplankton shows close associations to the hydrography of the north-east Atlantic, from the overall biomass to the timing and ending of the seasonal growth period. At larger-scales, atmospheric forcing (principally governed by the North Atlantic Oscillation index) has a dominant effect on decadal variability of phytoplankton populations in the north-east Atlantic. Although there is considerable regional variability in the long-term trends in phytoplankton biomass and community structure, underlying patterns emerged to reveal common trends. During the last decade, there has been a considerable increase in phytoplankton bion1ass in most regions (particularly the North Sea) and an increase in the dominance of dinoflagellates amongst the phytoplankton community, while the opposite pattern was observed for the northern oceanic area of the north-east Atlantic. These different spatial responses show similar patterns to changes in the decadal variability of sea-surface temperature influenced by the North Atlantic Oscillation index. While atmospheric variability plays a key role in the overall long-term and regional patterns of phytoplankton, oceanic influences on the North Sea ecosystem have been underestimated in the past. The anomalous phytoplankton biomass values, and large community shifts in the North Sea, are associated with episodic hydrographic events seen during the late 1970s/early 1980s and the late 1980s/early 1990s. It is suggested that these hydrographic events conspire to produce anomalous ocean climate conditions in the North Sea which persist for a number of years and are significant enough to alter the overall ecology of the North Sea.Sir Alister Hardy Foundation for Ocean Scienc

High resolution cathodoluminescence hyperspectral imaging of surface features in InGaN/GaN multiple quantum well structures

InGaN/GaN multiple quantum wells (MQWs) have been studied by using cathodoluminescence hyperspectral imaging with high spatial resolution. Variations in peak emission energies and intensities across trench-like features and V-pits on the surface of the MQWs are investigated. The MQW emission from the region inside trench-like features is red-shifted by approximately 45 meV and more intense than the surrounding planar regions of the sample, whereas emission from the V-pits is blue-shifted by about 20 meV and relatively weaker. By employing this technique to the studied nanostructures it is possible to investigate energy and intensity shifts on a 10 nm length scale.Comment: 3 pages, 3 figure

Who’s Afraid of the Big Bad Tax-Free Liquidating Distribution? Ideological Debates on Taxation and the Repeal of General Utilities

The General Utilities doctrine, named for the 1935 Supreme Court decision allowing a corporation to distribute appreciated assets to shareholders without reporting a taxable gain, was once known as one of seven fundamental principles of American corporate taxation. The doctrine’s popularity reached its peak in 1954, when Congress formally incorporated it into the Internal Revenue Code. Despite this esteemed position among tax-law doctrines, General Utilities was routinely criticized because, among other things, it allowed a situational (and arbitrary) reprieve from “double taxation” of corporate income. Corporate income is functionally taxed twice in the sense that the corporation owes tax on the profits earned by its operations and the shareholders owe individual income taxes on the leftover, after-tax profits the corporation distributes to shareholders. The General Utilities doctrine reflects a tension that has existed throughout tax law history—that is, whether double taxation of corporate income is good policy

Shareholder Wealth Maximization: A Schelling Point

(Excerpt) Imagine a reality television game show where two contestants begin the game in two different places in New York City. The object of the game is for the two contestants to find each other, but they do not know anything about each other and they have no way of communicating. If they succeed, both contestants win a prize. If they fail, they get nothing. With no ability to explicitly bargain over the meeting, the parties have to make an educated guess about what the other person is most likely to do. Most people, confronted with this sort of tacit coordination game, will attempt the meeting at a major New York City landmark such as the Empire State Building. Absent any other clues as to the optimal equilibrium meeting point, both parties choose a place that is imaginatively unique and intuitive, expecting that the place will also be unique in the other’s imagination. The Empire State Building stands out not because it is a particularly optimal meeting place, but rather because it is iconic, nearly synonymous with New York City itself. This is called a “focal point,” or “Schelling point,” after Professor Thomas Schelling. There are two important observations that arise from the New York City game: first, that people can coordinate without communication and, second, that value-creating outcomes can be achieved despite multiple equilibria and high transaction costs. As to the former, the fact that many more people than would be expected by chance would likely collect the prize illustrates that coordination without communication is possible

Competition Upstream of Amazon

The rise of large, market-concentrating technology firms like Amazon, Inc. is driving commentators, regulators, and politicians to rethink the law of antitrust. In particular, “New Antitrust” reformers propose that the narrow focus on consumer welfare has caused antitrust law to stop too short in corralling the broader social and economic consequences of Big Tech’s “bigness.” Proponents of the consumer welfare standard argue that it has worked well to distinguish beneficial competition from harmful aggression and, further, to reduce costly legal uncertainty. There is now momentum for substantial reform to antitrust law and practice and a growing debate about what such reform might include. This Article contributes to the debate by presenting a modest case study of a market that is evolving on Amazon, Inc.’s Marketplace platform: the market for nonprescription components of continuous positive air pressure (CPAP) machines, medical devices prescribed to patients suffering from sleep apnea. The study reveals two observations. First, the underlying economic and doctrinal logic of consumer welfare antitrust remains sound. Second, the study illustrates positive social consequences beyond just the economic wealth and welfare that the consumer welfare standard uses as its lodestar. This Article focuses on that proponents of the consumer welfare approach are wrong to dismiss indirect negative social and economic consequences of bigness, such as harm to small business, stifling of innovation, and inequality. This Article follows the New Antitrust reformers into this space by illustrating counterbalancing social and economic consequences from Amazon’s consolidation, including a thriving network of small and innovative dealers, other small innovators that serve them, increased employment opportunities, and even lowering of healthcare costs. Amazon has grown large and has concentrated online retail and related logistics, but its largeness has spurred innovation, competition, and social value-creation just upstream