41,663 research outputs found
A database of genus 2 curves over the rational numbers
We describe the construction of a database of genus 2 curves of small
discriminant that includes geometric and arithmetic invariants of each curve,
its Jacobian, and the associated L-function. This data has been incorporated
into the L-Functions and Modular Forms Database (LMFDB).Comment: 15 pages, 7 tables; bibliography formatting and typos fixe
Behavioural simulation of biological neuron systems using VHDL and VHDL-AMS
The investigation of neuron structures is an incredibly difficult and complex task that yields relatively low rewards in terms of information from biological forms (either animals or tissue). The structures and connectivity of even the simplest invertebrates are almost impossible to establish with standard laboratory techniques, and even when this is possible it is generally time consuming, complex and expensive. Recent work has shown how a simplified behavioural approach to modelling neurons can allow “virtual” experiments to be carried out that map the behaviour of a simulated structure onto a hypothetical biological one, with correlation of behaviour rather than underlying connectivity. The problems with such approaches are numerous. The first is the difficulty of simulating realistic aggregates efficiently, the second is making sense of the results and finally, it would be helpful to have an implementation that could be synthesised to hardware for acceleration. In this paper we present a VHDL implementation of Neuron models that allow large aggregates to be simulated. The models are demonstrated using a system level VHDL and VHDL-AMS model of the C. Elegans locomotory system
Performance of nanocrystalline Ni3N as a negative electrode for sodium-ion batteries
Nickel nitride is synthesised by high temperature ammonolysis of nickel(II) hexamine and tris(ethylenediamine) salts. Its electrochemical characteristics are examined in half-cells vs. lithium and sodium. Samples with high surface area are found to have significant reversible charge storage capacity in sodium cells and hence to be a promising negative electrode material for sodium-ion batteries
Can auctions control market power in emissions trading markets.
Using eight sessions (twenty-four ten-period markets) in a double ABA cross-over design, we demonstrate clear evidence of market power in double-auction emission trading markets (agents who are not constrained to only buy or sell). Conventional theory predicts that in half of the market-power environments monopsony should emerge and in half monopoly should emerge. Market-power outcomes are frequently observed, most often in the form of price discrimination, and most effectively by monopsonists.
Modeling Lifetime Earnings Paths: Hypothetical versus Actual Workers
To assess the distributional effects of social security reform proposals, it is essential to have good information on real-world workers’ lifetime earnings trajectories. Until recently, however, policymakers have relied on hypothetical earnings profiles for policy analysis. We use actual lifetime earnings data from the Health and Retirement Study (HRS) to compare actual workers’ covered earnings profiles to these hypothetical profiles. We show that the hypothetical profiles do not track earnings patterns of current retirees; thus lifetime pay levels are much higher than for most HRS workers. Therefore, using hypothetical profiles could misrepresent benefits paid and taxes collected under such reforms.
The applicability of self-regulation theories in sport : goal adjustment capacities, stress appraisals, coping and well-being among athletes
Objectives: We examined a model, informed by self-regulation theories, which included goal adjustment capacities, appraisals of challenge and threat, coping, and well-being. Design: Prospective. Methods: Two hundred and twelve athletes from the United Kingdom (n = 147) or Australia (n = 65), who played team (n = 135) or individual sports (n = 77), and competed at international (n = 7), national (n = 11), county (n = 67), club (n = 84), or beginner (n = 43) levels participated in this study. Participants completed measures of goal adjustment capacities and stress appraisals two days before competing. Athletes also completed questions on coping and well-being within three hours of their competition ending. Results: The way an athlete responds to an unattainable goal is associated with his or her well-being in the period leading up to and including the competition. Goal reengagement positively predicted well-being, whereas goal disengagement negatively predicted well-being. Further, goal reengagement was positively associated with challenge appraisals, which in turn was linked to task-oriented coping, and task-oriented coping positively associated with well-being. Conclusion: When highly-valued goals become unattainable, consultants could encourage athletes to seek out alternative approaches to achieve the same goal or help them develop a completely new goal
Importance of understanding variable and transient energy demand in large multi-product industrial plants for process integration
There have been some news releases claiming that Professor Henle in Germany has found the chemical identity of UMF, and that in future chemical analysis will be used instead of assays of antibacterial activity to indicate the level of UMF in manuka honey. Both of these claims are misleading. Because the level of active substance in manuka honey is an unreliable indication of the level of antibacterial activity and can be very misleading, it is hard to see any commercial advantage for it to be used to indicate antibacterial activity other than if someone wanted to fool the consumer into thinking that the higher numbers are giving them a level of antibacterial activity that is far higher than they are really getting
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