3,908 research outputs found

    Holistic analysis of mix protocols

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    Security protocols are often analysed in isolation as academic challenges. However, the real world can require various combinations of them, such as a certified email protocol executed over a resilient channel, or the key registration protocol to precede the purchase protocols of Secure Electronic Transactions (SET). We develop what appears to be the first scalable approach to specifying and analysing mix protocols. It expands on the Inductive Method by exploiting the simplicity with which inductive definitions can refer to each other. This lets the human analyst study each protocol separately first, and then derive holistic properties about the mix. The approach, which is demonstrated on the sequential composition of a certification protocol with an authentication one, is not limited by the features of the protocols, which can, for example, share message components such as cryptographic keys and nonces. It bears potential for the analysis of complex protocols constructed by general composition of others

    Diagnosing Type 2 diabetes before patients complain of diabetic symptoms—clinical opportunistic screening in a single general practice

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    In the UK, patients normally see their general practitioner first and 86% of the health needs of the population are managed in general practice, with 14% being referred to specialist/hospital care. Early diagnosis is the privilege of general practice since general practitioners make most medical diagnoses in the NHS. Their historic aim has been to diagnose as early as possible and if possible before patients are aware of symptoms. Over time, diagnoses are being made earlier in the trajectory of chronic diseases and pre-symptomatic diagnoses through tests like cervical screening. Earlier diagnosis benefits patients and allows earlier treatment. In diabetes, the presence of lower HbA1c levels correlates with fewer complications. Methodologically, single practice research means smaller populations but greater ability to track patients and ask clinicians about missing data. All diagnoses of type 2 diabetes, wherever made, were tracked until death or transfer out. Clinical opportunistic screening has been undervalued and is more cost-effective than population screening. It works best in generalist practice. Over 19 consecutive years, all 429 patients with type 2 diabetes in one NHS general practice were analysed. The prevalence of type 2 diabetes rose from 1.1% to 3.0% of the registered population. Since 2000, 95.9% were diagnosed within the general practice and the majority (70/121 = 57.9%) of diagnoses were made before the patients reported any diabetes-related symptom. These patients had median HbA1c levels 1.1% lower than patients diagnosed after reporting symptoms, a clinically and statistically significant difference (P = 0.01)

    Maine\u27s Science and Engineering Brain Drain: How Much and Why?

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    More than the traditional economic ingredients, the new global economy is being built around talented people with special knowledge and skills, those with the capacity to innovate and the entrepreneurial wherewithal to turn ideas into commercial products. Hence many states are shifting economic development strategies away from efforts that market commodities such as low tax rates and cheap labor, and toward efforts that amass and equip talented people with the tools of innovation. In short, states are beginning to think about strategies for recruiting and/or retaining talented workers. In this regard, the Southern Technology Council conducted a national study to compare states on their performance in retaining their own recent science and engineering graduates and/or attracting similar graduates from states elsewhere in the country. How is Maine doing? they ask. In a word, poorly. The authors compare Maine to other states on a number of performance indicators and predictor variables to assess why this is so. They suggest Maine take bold steps now to prevent the continued loss of its most important commodity of the future

    Biochemical and genetic controls exerted by plant mitochondria

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    AbstractHigher plant mitochondria contain two terminal oxidases, cytochrome c oxidase and a cyanide-resitant ‘alternative’ oxidase. Electron flux through these two respiratory pathways is controlled by environmental conditions, stimuli received by mitochondria. In general, stresses such as cold, wounding, pathogen attack and others favor electron flow through the alternative oxidase. One of the proposed functions of the alternative pathway is to relieve the tricarboxylic acid (TCA) cycle of inhibition from cytochrome pathway products and allow the cycle to furnish carbon skeletons for anabolic requirements. We are currently investigating, with an NADP-linked isocitrate dehydrogenase in plant mitochondria, a possible link between respiratory control and carbon flux from the TCA cycle. Regulation of the nuclear gene encoding the alternative oxidase, Aox1, is also being employed as a model for perception of the many stresses by the mitochondria and transfer of these signals to the nucleus. Our initial results indicate that hydrogen peroxide is an intermediate in this signalling process

    Towards Verifying Voter Privacy Through Unlinkability

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    International audienceThe increasing official use of security protocols for electronic voting deepens the need for their trustworthiness, hence for their formal verification. The impossibility of linking a voter to her vote, often called voter privacy or ballot secrecy, is the core property of many such protocols. Most existing work relies on equivalence statements in cryptographic extensions of process calculi. This paper provides the first theorem-proving based verification of voter privacy and overcomes some of the limitations inherent to process calculi-based analysis. Unlinkability between two pieces of information is specified as an extension to the Inductive Method for security protocol verification in Isabelle/HOL. New message operators for association extraction and synthesis are defined. Proving voter privacy demanded substantial effort and provided novel insights into both electronic voting protocols themselves and the analysed security goals. The central proof elements are described and shown to be reusable for different protocols with minimal interaction

    Ferromagnetic dynamics detected via one- and two-magnon NV relaxometry

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    The NV center in diamond has proven to be a powerful tool for locally characterizing the magnetic response of microwave excited ferromagnets. To date, this has been limited by the requirement that the FMR excitation frequency be less than the NV spin resonance frequency. Here we report NV relaxometry based on a two-magnon Raman-like process, enabling detection of FMR at frequencies higher than the NV frequency. For high microwave drive powers, we observe an unexpected field-shift of the NV response relative to a simultaneous microwave absorption signal from a low damping ferrite film. We show that the field-shifted NV response is due to a second order Suhl instability. The instability creates a large population of non-equilibrium magnons which relax the NV spin, even when the uniform mode FMR frequency exceeds that of the NV spin resonance frequency, hence ruling out the possibility that the NV is relaxed by a single NV-resonant magnon. We argue that at high frequencies the NV response is due to a two-magnon relaxation process in which the difference frequency of two magnons matches the NV frequency, and at low frequencies we evaluate the lineshape of the one-magnon NV relaxometry response using spinwave instability theory

    The Grizzly, November 21, 2002

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    Well-known Political Consultant Mark Moskowitz at Ursinus • Greek Organizations Come Together for GPC Activities Fair • Too Big for our Buildings • Eye on Your Future: Internships • \u27Tis the Season to Ignore the Needy? • Do You Care About Political Apathy? • Should a Minor Receive the Death Penalty? • Opinions: Feeling Uninvited in Your Own Home; Smoking or Non? You Decide; 17-Year-Old Could be Tried as Adult • Be a Film Society Member • Howard, Roesch Look to Lead Wrestling to C.C. Championship • On Your Mark...Indoor Track Ready to Go • Dougherty Rockets Off to National Meethttps://digitalcommons.ursinus.edu/grizzlynews/1526/thumbnail.jp
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