42 resultados para Keyed One-Way Functions


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A variety of short time delays inserted between pairs of subjects were found to affect their ability to synchronize a musical task. The subjects performed a clapping rhythm together from separate sound-isolated rooms via headphones and without visual contact. One-way time delays between pairs were manipulated electronically in the range of 3 to 78 ms. We are interested in quantifying the envelope of time delay within which two individuals produce synchronous per- formances. The results indicate that there are distinct regimes of mutually coupled behavior, and that `natural time delay'o¨delay within the narrow range associated with travel times across spatial arrangements of groups and ensembleso¨supports the most stable performance. Conditions outside of this envelope, with time delays both below and above it, create characteristic interaction dynamics in the mutually coupled actions of the duo. Trials at extremely short delays (corresponding to unnaturally close proximity) had a tendency to accelerate from anticipation. Synchronization lagged at longer delays (larger than usual physical distances) and produced an increasingly severe deceleration and then deterioration of performed rhythms. The study has implications for music collaboration over the Internet and suggests that stable rhythmic performance can be achieved by `wired ensembles' across distances of thousands of kilometers.

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Age-related macular degeneration (AMD) is the most common cause of blindness in older people in developed countries, and risk for this condition may be classified as genetic or environmental, with an interaction between such factors predisposing to this disease. This study investigated the relationship between AMD risk genes, macular pigment optical density (MPOD), which may protect against AMD, and serum concentrations of the macular carotenoids, lutein (L) and zeaxanthin (Z). This was a cross-sectional study of 302 healthy adult subjects. Dietary intake of L and Z was assessed by food frequency questionnaire, and MPOD was measured by customized heterochromatic flicker photometry. We also calculated MPOD Area as the area of MP under the spatial profile curve, to reflect MP across the macula. Serum L and Z were measured by HPLC. Genotyping of tag SNPs in the genes CFH, ARMS2, C3, C2 and BF was undertaken with multiplex polymerase chain reaction (PCR) and primer extension methodology (ABI Snapshot, ABI Warrington UK) on DNA extracted from peripheral blood. The mean ± SD (range) age of the subjects in this study was 48 ± 11 (21-66) years. There was a statistically significant association between CFH genotype and family history of AMD, with subjects having two non-risk CFH haplotypes (n =35), or one non-risk and one protective CFH haplotype (n = 33), being significantly more likely to have a negative family history of AMD (Pearson Chi square: p = 0.001). There was no significant association between the AMD risk genes investigated and either MPOD (One way ANOVA: p > 0.05) or serum concentrations of L or Z (One way ANOVA: p > 0.05, for both). Subjects who were homozygous for risk alleles of both CFH and ARMS2 (n = 4) had significantly lower MPOD at 0.5_ and 1_ retinal eccentricity (Independent samples t test: p

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One way to restore physiological blood flow to occluded arteries involves the deformation of plaque using an intravascular balloon and preventing elastic recoil using a stent. Angioplasty and stent implantation cause unphysiological loading of the arterial tissue, which may lead to tissue in-growth and reblockage; termed “restenosis.” In this paper, a computational methodology for predicting the time-course of restenosis is presented. Stress-induced damage, computed using a remaining life approach, stimulates inflammation (production of matrix degrading factors and growth stimuli). This, in turn, induces a change in smooth muscle cell phenotype from contractile (as exists in the quiescent tissue) to synthetic (as exists in the growing tissue). In this paper, smooth muscle cell activity (migration, proliferation, and differentiation) is simulated in a lattice using a stochastic approach to model individual cell activity. The inflammation equations are examined under simplified loading cases. The mechanobiological parameters of the model were estimated by calibrating the model response to the results of a balloon angioplasty study in humans. The simulation method was then used to simulate restenosis in a two dimensional model of a stented artery. Cell activity predictions were similar to those observed during neointimal hyperplasia, culminating in the growth of restenosis. Similar to experiment, the amount of neointima produced increased with the degree of expansion of the stent, and this relationship was found to be highly dependant on the prescribed inflammatory response. It was found that the duration of inflammation affected the amount of restenosis produced, and that this effect was most pronounced with large stent expansions. In conclusion, the paper shows that the arterial tissue response to mechanical stimulation can be predicted using a stochastic cell modeling approach, and that the simulation captures features of restenosis development observed with real stents. The modeling approach is proposed for application in three dimensional models of cardiovascular stenting procedures.

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A survey of red and grey squirrel habitat associations in Northern Ireland was conducted between September 1994 and August 1995. Two hundred and sixty-one sites were visited and a list of habitat characteristics for each site was noted. Multiple discriminant function analysis of the habitat type was employed to group squirrel occurrence, while contingency analysis examined independence of habitat type and squirrel species presence. Habitat associations differed between the two species. One-way ANOVAs of habitat data suggested that sites occupied by red squirrels only were predominantly coniferous, at higher altitude and latitude and much larger in area than sites occupied by grey squirrels only, which were mostly deciduous. When both species were sympatric, sites were more likely to be coniferous and larger in area than sites occupied by either species. Grey squirrels were less frequent than expected in upland plantations and more frequent than expected in parkland and gardens; the opposite was true for red squirrels. The mean distance between sites with only red squirrels and the nearest site with grey squirrels was greater than the mean distance between sites with only grey squirrels and the nearest site with red squirrels. An approach to conserving the red squirrel in view of the continued expansion in the grey squirrel's distribution in Ireland is discussed.

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This article explores two rival understandings of production and what it means to be a rational productive subject. Against ‘technicist’ models of productive reason, it defends a ‘phronetic’ model on both normative and pragmatic grounds. The discussion begins with a description of the general principles underpinning technicist theories of workplace organisation, principles which continue to inform work design approaches to this day. The technicist model is thereafter criticised on three counts: that it represents a specific managerial agenda which privileges sectional interests; that it is suspect morally for a number of reasons; and that despite its aspiration of arriving at ‘one best method’, it represents but one way of organising work processes. The phronetic model is then set out using the notion of ‘practices’ as a guide. This notion is important in providing a view of production in which technical reason is subsumed under a broader practical reason incorporating individual experience and judgement. Against the charge that this view is merely an instance of nostalgic craft romanticism having little relevance to present industrial realities, there are recognisable contemporary instances of phronetic production, one of the most interesting being Volvo’s innovations in automotive assembly systems.

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In this paper, we introduce a macroscopic model for road traffic accidents along highway sections. We discuss the motivation and the derivation of such a model, and we present its mathematical properties. The results are presented by means of examples where a section of a crowded one-way highway contains in the middle a cluster of drivers whose dynamics are prone to road traffic accidents. We discuss the coupling conditions and present some existence results of weak solutions to the associated Riemann Problems. Furthermore, we illustrate some features of the proposed model through some numerical simulations. © The authors 2012.

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Background: Mandatory fortification of grain products with folic acid was introduced recently in the United States, a policy expected to result in a mean additional intake of 100 mu g/d. One way of predicting the effectiveness of this measure is to determine the effect of removing a similar amount of folic acid as fortified food from the diets of young women who had been electively exposed to chronic fortification.

Objective: The objective was to examine the effect on folate status of foods fortified with low amounts of folic acid.

Design: We investigated the changes in dietary intakes and in red blood cell and serum concentrations of folate in response to removing folic acid-fortified foods for 12 wk from the diets of women who reportedly consumed such foods at least once weekly (consumers).

Results: Consumers (n = 21) had higher total folate intakes (P = 0.002) and red blood cell folate concentrations (P = 0.023) than nonconsumers (women who consumed folic acid-fortified foods less than once weekly; n = 30). Of greater interest, a 12-wk intervention involving the exclusion of these foods resulted in a decrease in folate intake of 78 +/- 56 mu g/d (P < 0.001), which was reflected in a significant reduction in red blood cell folate concentrations (P < 0.05).

Conclusions: Cessation of eating folic acid-fortified foods resulted in removing 78 mu g folic acid/d from the diet. Over 12 wk this resulted in a lowering of red blood cell folate concentrations by 111 nmol/L (49 mu g/L). This magnitude of change in folate status in women can be anticipated as a result of the new US fortification legislation and is predicted to have a significant, although not optimal, effect in preventing neural tube defects.

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Service user forums have the potential for improving awareness of services, empowering service users and strengthening community partnerships within an inclusive treatment and rehabilitation framework. The research aimed to investigate perspectives about service user involvement in order to inform the development of effective service user forum(s) in west Ireland. A total of 30 interviews with key service providers and 12 interviews with service users were conducted, with interview questions focusing on: (1) awareness of the Service User Support Team and (2) barriers to service user involvement and the development of service user forums in the region. An integrated data collection and thematic analysis was undertaken. Current levels of service user involvement were low, restricted by one-way communication and appeared grounded in user-provider power differentials and stigma relating to drug dependency. Service providers queried the actual terms of reference, capacity and training that would be needed for service user forums to advocate and lobby for service users. The use of existing support groups, creation of internet user forums and rotation of rural meetings were recommended to promote engagement among service users. The research underscores the need for transparency, resources and a framework for good practice that reflects a participatory approach


Read More: http://informahealthcare.com/doi/abs/10.3109/09687637.2012.671860

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Drawing on recently declassified documents from the archive of the Foreign Ministry of the People’s Republic of China (PRC), this article looks at China’s relationship with North Korea during and immediately after the Korean War. Although previous scholarship has touched on PRC–North Korean military ties during the war, this article is the first in-depth analysis of issues that are less well understood, notably China’s efforts to cope with a huge influx of refugees from North Korea, the PRC’s economic assistance during the war and in the early postwar reconstruction, and Chinese educational and ideological support for North Korean professionals and party cadres. The article shows that the extensive military coordination between Beijing and Pyongyang was only one way in which the war brought North Korea and the PRC into a closer relationship

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Few markers distinguish between different dementia types. As dementia affects many body systems outside the central nervous system, we investigated gastrointestinal regulatory peptides as possible disease markers in Alzheimer's Disease (AD) and vascular dementia (VaD). Subjects with mild-to-moderate dementia were diagnosed as probable AD and VaD according to defined criteria. Gastrointestinal peptides were stimulated using a standardized meal test, administered after an overnight fast to 58 dementia patients (40 AD, 18 VaD) and 47 controls matched for age and sex. Blood samples were taken at designated time intervals, and basal and stimulated plasma concentrations of eleven peptides were determined by radio-immunoassay. Results were analysed using the Kruskal-Wallis one-way analysis of variance; the Mann-Whitney U test was used in post hoc analysis where appropriate. There were significant differences in somatostatin levels but in none of the other peptides. Basal somatostatin was significantly increased in VaD compared to controls (p

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Arching or compressive membrane action (CMA) in reinforced concrete slabs occurs as a result of the great difference between the tensile and compressive strength of concrete. Cracking of the concrete causes a migration of the neutral axis which is accompanied by in-plane expansion of the slab at its boundaries. If this natural tendency to expand is restrained, the development of arching action enhances the strength of the slab. The term arching action is normally used to describe the arching phenomenon in one-way spanning slabs and compressive membrane action is normally used to describe the arching phenomenon in two-
way spanning slabs. This encyclopedic article presents the background to the discovery of the phenomenon of arching action and presents a factual history of the approaches to the treatment of arching action in the United Kingdom and North American bridge deck design codes. The article summarises the theoretical methodology used in the United Kingdom Design Manual for Roads and Bridges, BD81/02, which was based on the work by Kirkpatrick, Rankin & Long at Queen's University Belfast.

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Background: One way to tackle health inequalities in resource-poor settings is to establish links between doctors and health professionals there and specialists elsewhere using web-based telemedicine. One such system run by the Swinfen Charitable Trust has been in existence for 13 years which is an unusually long time for such systems.

Objective: We wanted to gain some insights into whether and how this system might be improved.

Methods: We carried out a survey by questionnaire of referrers and specialists over a six months period.

Results: During the study period, a total of 111 cases were referred from 35 different practitioners, of whom 24% were not doctors. Survey replies were received concerning 67 cases, a response rate of 61 per cent. Eighty-seven per cent of the responding referrers found the telemedicine advice useful, and 78% were able to follow the advice provided. As a result of the advice received, the diagnosis was changed in 22% of all cases and confirmed in a further 18 per cent. Patient management was changed in 33 per cent. There was no substantial difference between doctors and non-doctors. During the study period, the 111 cases were responded to by 148 specialists, from whom 108 replies to the questionnaire were received, a response rate of 73 per cent. About half of the specialists (47%) felt that their advice had improved the management of the patients. There were 62 cases where it was possible to match up the opinions of the referrer and the consultants about the value of a specific teleconsultation. In 34 cases (55%) the referrers and specialists agreed about the value. However, in 28 cases (45%) they did not: specialists markedly underestimated the value of a consultation compared to referrers. Both referrers and specialist were extremely positive about the system which appears to be working well. Minor changes such as a clearer referral template and an improved web interface for specialists may improve it.

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We introduce a general scheme for sequential one-way quantum computation where static systems with long-living quantum coherence (memories) interact with moving systems that may possess very short coherence times. Both the generation of the cluster state needed for the computation and its consumption by measurements are carried out simultaneously. As a consequence, effective clusters of one spatial dimension fewer than in the standard approach are sufficient for computation. In particular, universal computation requires only a one-dimensional array of memories. The scheme applies to discrete-variable systems of any dimension as well as to continuous-variable ones, and both are treated equivalently under the light of local complementation of graphs. In this way our formalism introduces a general framework that encompasses and generalizes in a unified manner some previous system-dependent proposals. The procedure is intrinsically well suited for implementations with atom-photon interfaces.

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This paper characterizes efficient networks in player and partner heterogeneity models for both the one-way flow and the two-way flow models. Player (partner) dependent network formation allows benefits and costs to be player (partner) heterogeneous which is an important extension for modeling social networks in the real world. Employing widely used assumptions, I show that efficient networks in the two way flow model are minimally connected and have star or derivative of star type architectures, whereas efficient networks in the one way flow model have wheel architectures.

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Making room for new marine uses and safeguarding more traditional uses, without degrading the marine environment, will require the adoption of new integrated management strategies. Current management frameworks do not facilitate the integrated management of all marine activities occurring in one area. To address this issue, the government developed Harnessing Our Ocean Wealth – An Integrated Marine Plan (IMP) for Ireland. Harnessing Our Ocean
Wealth presents a ‘roadmap’ for adopting an integrated approach to marine governance and for achieving the Government’s ambitious targets for the maritime sector, including: exceeding €6.4 billion turnover annually by 2020, and doubling its contribution to GDP to 2.4% by 2030. As part of this roadmap, Harnessing Our Ocean Wealth endorses the development of an appropriate Marine Spatial Planning (MSP) Framework. One way to develop an MSP Framework is to learn from early adapters. Critical assessments of key
elements of MSP as implemented in early initiatives can serve to inform the development of an appropriate framework. The aim of this project is to contribute to the development of this framework by reporting on
MSP best practice relevant to Ireland. Case study selection and evaluation criteria are outlined in the next section. This is followed by a presentation of case study findings. The final section of the report focuses on outlining how the lessons could be transferred to the Irish context.