1,312 research outputs found

    Diet, nutrition and the prevention of type 2 diabetes

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    Objectives: The overall objective of this study was to evaluate and provide evidence and recommendations on current published literature about diet and lifestyle in the prevention of type 2 diabetes. Design: Epidemiological and experimental studies, focusing on nutritional intervention in the prevention of type 2 diabetes are used to make disease-specific recommendations. Long-term cohort studies are given the most weight as to strength of evidence available. Setting and subjects: Numerous clinical trials and cohort studies in low, middle and high income countries are evaluated regarding recommendations for dietary prevention of type 2 diabetes. These include, among others, the Finnish Diabetes Prevention Study, US Diabetes Prevention Program, Da Qing Study; Pima Indian Study; Iowa Women’s Health Study; and the study of the US Male Physicians. Results: There is convincing evidence for a decreased risk of diabetes in adults who are physically active and maintain a normal body mass index (BMI) throughout adulthood, and in overweight adults with impaired glucose tolerance who lose weight voluntarily. An increased risk for developing type 2 diabetes is associated with overweight and obesity; abdominal obesity; physical inactivity; and maternal diabetes. It is probable that a high intake of saturated fats and intrauterine growth retardation also contribute to an increased risk, while non-starch polysaccharides are likely to be associated with a decreased risk. From existing evidence it is also possible that omega-3 fatty acids, low glycaemic index foods and exclusive breastfeeding may play a protective role, and that total fat intake and trans fatty acids may contribute to the risk. However, insufficient evidence is currently available to provide convincing proof. Conclusions: Based on the strength of available evidence regarding diet and lifestyle in the prevention of type 2 diabetes, it is recommended that a normal weight status in the lower BMI range (BMI 21–23) and regular physical activity be maintained throughout adulthood; abdominal obesity be prevented; and saturated fat intake be less than 7% of the total energy intake

    Effects of Noisy Oracle on Search Algorithm Complexity

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    Grover's algorithm provides a quadratic speed-up over classical algorithms for unstructured database or library searches. This paper examines the robustness of Grover's search algorithm to a random phase error in the oracle and analyzes the complexity of the search process as a function of the scaling of the oracle error with database or library size. Both the discrete- and continuous-time implementations of the search algorithm are investigated. It is shown that unless the oracle phase error scales as O(N^(-1/4)), neither the discrete- nor the continuous-time implementation of Grover's algorithm is scalably robust to this error in the absence of error correction.Comment: 16 pages, 4 figures, submitted to Phys. Rev.

    The experience of enchantment in human-computer interaction

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    Improving user experience is becoming something of a rallying call in human–computer interaction but experience is not a unitary thing. There are varieties of experiences, good and bad, and we need to characterise these varieties if we are to improve user experience. In this paper we argue that enchantment is a useful concept to facilitate closer relationships between people and technology. But enchantment is a complex concept in need of some clarification. So we explore how enchantment has been used in the discussions of technology and examine experiences of film and cell phones to see how enchantment with technology is possible. Based on these cases, we identify the sensibilities that help designers design for enchantment, including the specific sensuousness of a thing, senses of play, paradox and openness, and the potential for transformation. We use these to analyse digital jewellery in order to suggest how it can be made more enchanting. We conclude by relating enchantment to varieties of experience.</p

    The importance of long-term genetic monitoring of reintroduced populations: inbreeding in the natterjack toad (Epidalea calamita)

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    Genetic monitoring is an important, but frequently lacking, component of management actions to support long-term persistence in reintroduced populations. Populations that remain small, due to demographic processes and genetic diversity, are more likely to experience a second extinction event. The natterjack toad (Epidelea calamita) is legally protected in Britain and was the subject of a reintroduction programme in the 1990s. However, subsequent genetic assessment has been mostly lacking. The aim of this study was to assess the genetic diversity of two reintroduced populations of natterjack toads in order to inform conservation management. Adults were sampled and nine microsatellites amplified to assess neutral genetic variation within each site and for comparison with the source population. Inbreeding was observed at the reintroduction sites, as evidenced by high FIS values (0.43 and 0.72), low observed compared to expected heterozygosities, and significant deviation from Hardy-Weinberg equilibrium. Observed heterozygosity is currently lower in the reintroduction sites than it was in the source population at the time of the reintroductions (Red Rocks: 0.15±0.20; Talacre: 0.12±0.20; Ainsdale (source): 0.29). Evidence for a bottleneck was not found, although this is likely a result of sampling overlapping generations. No within-site population structuring was observed. Such low genetic diversity has not previously been recorded in any natterjack population. Genetic rescue, combined with pool creation, is the most viable option for safeguarding the species at these sites into the future. Our work highlights the importance of ongoing genetic monitoring, in collaboration with conservation organisations, to support conservation management

    Evolution of the Lyman-alpha Halos around High-Redshift Radio Galaxies

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    We have obtained the first constraints on extended Ly-alpha emission at z ~ 1 in a sample of five radio galaxies. We detect Ly-alpha emission from four of the five galaxies. The Ly-alpha luminosities range from 0.1 - 4 times 10^43 erg/s and are much smaller than those observed for halos around higher redshift radio galaxies. If the z ~ 1 radio galaxies are the descendents the z >~ 2 radio galaxies, then their Ly-alpha luminosities evolve strongly with redshift as ~(1+z)^5. There do not appear to be strong correlations between other parameters, such as radio power, suggesting that this observed evolution is real and not an observational artifact or secondary correlation. We speculate that this evolution of luminous halos may be due to gas depletion (as gas cools, settles, and forms stars) accompanied by an overall rise in the mean gas temperature and a decrease in specific star-formation rate in and around these massive galaxies.Comment: 5 pages, 4 figures, published in ApJ Letters, 694, L31-35 March 20 200

    Elementary gates for quantum computation

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    We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x,y)(x,y) to (x,x⊕y)(x,x \oplus y)) is universal in the sense that all unitary operations on arbitrarily many bits nn (U(2n2^n)) can be expressed as compositions of these gates. We investigate the number of the above gates required to implement other gates, such as generalized Deutsch-Toffoli gates, that apply a specific U(2) transformation to one input bit if and only if the logical AND of all remaining input bits is satisfied. These gates play a central role in many proposed constructions of quantum computational networks. We derive upper and lower bounds on the exact number of elementary gates required to build up a variety of two-and three-bit quantum gates, the asymptotic number required for nn-bit Deutsch-Toffoli gates, and make some observations about the number required for arbitrary nn-bit unitary operations.Comment: 31 pages, plain latex, no separate figures, submitted to Phys. Rev. A. Related information on http://vesta.physics.ucla.edu:7777

    Cosmic Necklaces and Ultrahigh Energy Cosmic Rays

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    Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network much smaller than the horizon. We estimate the flux of high-energy protons produced by monopole annihilation in the decaying closed loops. For some reasonable values of the parameters it is comparable to the observed flux of ultrahigh-energy cosmic rays.Comment: 10 pages, Revtex, 1 figur

    Open randomised trial of the (Arabin) pessary to prevent preterm birth in twin pregnancy with health economics and acceptability: STOPPIT-2-a study protocol.

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    INTRODUCTION: The STOPPIT-2 study aims to determine the clinical utility of the Arabin cervical pessary in preventing preterm birth in women with a twin pregnancy and a short cervix, about which there is current uncertainty. STOPPIT-2 will resolve uncertainty around effectiveness for women with a twin pregnancy and a cervical length of 35 mm or less, define adverse effects, ascertain acceptability and estimate National Health Service costs and savings. METHODS: STOPPIT-2 is a pragmatic multicentre open-label randomised controlled trial. Consenting women with twin pregnancy will have an transvaginal ultrasound scan of their cervical length performed between 18+0 and 20+6 weeks' gestation by an accredited practitioner: women with a cervical length of ≀35 mm will be eligible for inclusion in the treatment phase of the study. The intervention by the insertion of the Arabin cervical pessary will be compared with standard treatment (no pessary).The primary outcomes are (obstetric) spontaneous onset of labour for the mother leading to delivery before 34 weeks' gestation and (neonatal) a composite of specific adverse outcomes or death occurring up to the end of the first 4 weeks after the estimated date of delivery to either or both babies.We plan to recruit 500 women in the treatment phase of the study. Assuming a treatment effect of 0.6, and background rates of 35% and 18%, respectively, for each of the primary outcomes, our study has 85% power to detect a difference between the intervention and the control groups. ANALYSIS: Data will be analysed on the intention-to-treat principle. ETHICS: STOPPIT-2 was approved by the South East Scotland Ethics Committee 02 on 29 August 2014, reference number 14/SS/1031 IRAS ID 159610. DISSEMINATION: Peer reviewed journals, presentations at national and international scientific meetings. TRIAL REGISTRATION NUMBER: ISRCTN98835694 and NCT02235181
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