1,892 research outputs found

    Password Memorability and Strength using an Image

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    In this study, the goal was to determine if the use of an image may help the average user to create strong and unique passwords, as well as give aid to remember the password that was created. Furthermore, we aim to determine if the image helps improve the perception of security. The way we went about this was to develop a survey that provides the user with an image and asks them to create a password that may be strong enough for a school account using that image. Four groups were tested, a control with no image and three test groups each featuring a unique image

    Fattening foods - perceptions and misconceptions: a qualitative and quantitative exploration

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    Describes adults\u27 perceptions and beliefs about foods that are considered &quot;fattening&quot;. Use of qualitative and quantitative methods to determine the prevalence of the perceptions among adults; Range of factors that are considered when judging foods as &quot;fattening&quot;; Limitations in the public\u27s understandings of &quot;fattening foods&quot; which are inconsistent with dietary recommendations.<br /

    European Governments' Questionable Response: An Investigation into the Effects of Anti-Refugee Policies on Extremism in Europe

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    In light of the European migrant crisis, questions have been raised over the manner in which European countries have responded to the increase in refugees requiring settlement into the host state; with an upsurge in restrictive policies being witnessed. However, there is a lack of research into the effects of such policies. Therefore, this thesis tests the relationship between anti-refugee policies and extremism. This is achieved by analysing the effects of obstructive refugee policies (data for which provided by the Immigration Policies in Comparison dataset) on three levels of extremism: least violent, far-right vote share; intermediate-level, intentional homicide; most violent (gold standard of violent extremism), terror incidents. The study employs both a quantitative and qualitative approach, utilising a large-n study of the 24 OECD European states; which is followed by a comparative case study of a pro-refugee city in Mechelen (Belgium) and an evidently anti-refugee city in Cottbus (Germany). The principal findings are that, of the three levels of extremism, the strongest relationships were identified between anti-refugee policies and support for far-right parties. Additionally, the thesis provides evidence to suggest that there is a convincing causal link between effective and persistent refugee integration policies with a decrease in extremism. Implications of which are, that there is just indication that European governments should endeavour to employ further inclusive policies, aimed at their foreign inhabitants, in order to decrease the risk of extremism

    Mercurian impact ejecta: Meterorites and mantle

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    We have examined the fate of impact ejecta liberated from the surface of Mercury due to impacts by comets or asteroids, in order to study (1) meteorite transfer to Earth, and (2) re-accumulation of an expelled mantle in giant-impact scenarios seeking to explain Mercury's large core. In the context of meteorite transfer, we note that Mercury's impact ejecta leave the planet's surface much faster (on average) than other planet's in the Solar System because it is the only planet where impact speeds routinely range from 5-20 times the planet's escape speed. Thus, a large fraction of mercurian ejecta may reach heliocentric orbit with speeds sufficiently high for Earth-crossing orbits to exist immediately after impact, resulting in larger fractions of the ejecta reaching Earth as meteorites. We calculate the delivery rate to Earth on a time scale of 30 Myr and show that several percent of the high-speed ejecta reach Earth (a factor of -3 less than typical launches from Mars); this is one to two orders of magnitude more efficient than previous estimates. Similar quantities of material reach Venus. These calculations also yield measurements of the re-accretion time scale of material ejected from Mercury in a putative giant impact (assuming gravity is dominant). For mercurian ejecta escaping the gravitational reach of the planet with excess speeds equal to Mercury's escape speed, about one third of ejecta re-accretes in as little as 2 Myr. Thus collisional stripping of a silicate proto-mercurian mantle can only work effectively if the liberated mantle material remains in small enough particles that radiation forces can drag them into the Sun on time scale of a few million years, or Mercury would simply re-accrete the material.Comment: 14 pages. Submitted to Meteoritics and Planetary Scienc

    Characterization of a 3D matrix bioreactor for scaled production of human mesenchymal stem cells

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    Human Mesenchymal Stem Cells (hMSCs) are multipotent, immune-privileged, and possess the capacity to proliferate ex-vivo, making them a good candidate for stem cell therapy. However, a reliable scalable production system for hMSCs is needed to fuel the growing field of regenerative medicine. Current growth of hMSCs is achieved through adherent 2D methods using tissue culture flasks or cell factory systems. These processes are labor intensive and can lead to low purity and poor yield of hMSCs due to the limited control of culture conditions inherent in these systems. In this work, we are investigating a novel 3D honeycomb matrix culture system for controlled high density hMSC production. We have assessed compatibility of the hMSCs on the honeycomb matrix and developed a scale down model bioreactor for development and characterization. Computational Fluid Dynamic (CFD) modeling is used in parallel with the described in-vitro experimentation to characterize shear profiles and oxygen transport for optimization of the conditions to support high cell density hMSC cultures. These techniques will potentially allow for higher yield and purity of hMSCs to meet the large quantities of cells needed for emerging whole cell therapies

    Ontogenetic colour changes in an insular tree species: signalling to extinct browsing birds?

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    Summary • Animals often use colours to hide from predators (crypsis) or advertise defences (aposematism), but there is little evidence for colour-based defence in plants. • Here, we test whether ontogenetic changes in leaf colour of lancewood (Pseudopanax crassifolius) may have been part of a defensive strategy against flightless browsing birds called moa, which were once the only large herbivores in New Zealand. We tested this hypothesis by conducting spectrographic measurements on differentsized plants grown in a common garden. We also compared these results with observations on a closely related, derived species that evolved in the absence of moa on the Chatham Islands. • Spectrographic analyses showed that birds would have difficulty distinguishing seedling leaves against a background of leaf litter. Conversely, brightly coloured tissues flanking spines on sapling leaves are highly conspicuous to birds. Once above the reach of the tallest known moa, adults produce leaves that are typical in appearance to adult leaves. The Chatham Island species lacks ontogenetic colour changes entirely. • Overall, the results indicate that P. crassifolius goes through a remarkable series of colour changes during development, from cryptically coloured seedlings to aposematically coloured saplings, which may have formed a defensive strategy to protect against giant browsing birds

    Public perceptions of cancer: a qualitative study of the balance of positive and negative beliefs

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    Objectives: Cancer's insidious onset and potentially devastating outcomes have made it one of the most feared diseases of the 20th century. However, advances in early diagnosis and treatment mean that death rates are declining, and there are more than 30 million cancer survivors worldwide. This might be expected to result in more sanguine attitudes to the disease. The present study used a qualitative methodology to provide an in-depth exploration of attitudes to cancer and describes the balance of negative and positive perspectives. Design: A qualitative study using semistructured interviews with thematic analysis. Setting: A university in London, UK. Participants: 30 participants (23–73 years), never themselves diagnosed with cancer. Results: Accounts of cancer consistently incorporated negative and positive views. In almost all respondents, the first response identified fear, trauma or death. However, this was followed—sometimes within the same sentence—by acknowledgement that improvements in treatment mean that many patients can survive cancer and may even resume a normal life. Some respondents spontaneously reflected on the contradictions, describing their first response as a ‘gut feeling’ and the second as a more rational appraisal—albeit one they struggled to believe. Others switched perspective without apparent awareness. Conclusions: People appear to be ‘in two minds’ about cancer. A rapid, intuitive sense of dread and imminent death coexists with a deliberative, rational recognition that cancer can be a manageable, or even curable, disease. Recognising cancer's public image could help in the design of effective cancer control messages

    Effect of a Mobile Phone Intervention on Quitting Smoking in a Young Adult Population of Smokers: Randomized Controlled Trial

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR mhealth and uhealth, is properly cited. The complete bibliographic information, a link to the original publication on http://mhealth.jmir.org/, as well as this copyright and license information must be included.Background: Digital mobile technology presents a promising medium for reaching young adults with smoking cessation interventions because they are the heaviest users of this technology. Objective: The aim of this study was to determine the efficacy of an evidence-informed smartphone app for smoking cessation, Crush the Crave (CTC), on reducing smoking prevalence among young adult smokers in comparison with an evidence-informed self-help guide, On the Road to Quitting (OnRQ). Methods: A parallel, double-blind, randomized controlled trial with 2 arms was conducted in Canada to evaluate CTC. In total, 1599 young adult smokers (aged 19 to 29 years) intending to quit smoking in the next 30 days were recruited online and randomized to receive CTC or the control condition OnRQ for a period of 6 months. The primary outcome measure was self-reported continuous abstinence at the 6-month follow-up. Results: Overall follow-up rates were 57.41% (918/1599) and 60.48% (967/1599) at 3 and 6 months, respectively. Moreover, 45.34% (725/1599) of participants completed baseline, 3-, and 6-month follow-up. Intention-to-treat analysis (last observation carried forward) showed that continuous abstinence (N=1599) at 6 months was not significantly different at 7.8% (64/820) for CTC versus 9.2% (72/779) for OnRQ (odds ratio; OR 0.83, 95% CI 0.59-1.18). Similarly, 30-day point prevalence abstinence at 6 months was not significantly different at 14.4% (118/820) and 16.9% (132/779) for CTC and OnRQ, respectively (OR 0.82, 95% CI 0.63-1.08). However, these rates of abstinence were favorable compared with unassisted 30-day quit rates of 11.5% among young adults. Secondary measures of quit attempts and the number of cigarettes smoked per day at 6-month follow-up did not reveal any significant differences between groups. For those who completed the 6-month follow-up, 85.1% (359/422) of young adult smokers downloaded CTC as compared with 81.8% (346/423) of OnRQ, χ21(N=845)=1.6, P=.23. Furthermore, OnRQ participants reported significantly higher levels of overall satisfaction (mean 3.3 [SD 1.1] vs mean 2.6 [SD 1.3]; t644=6.87, P<.001), perceived helpfulness (mean 5.8 [SD 2.4] vs mean 4.3 [SD 2.6], t657=8.0, P<.001), and frequency of use (mean 3.6 [SD 1.2] vs mean 3.2 [SD 1.1], t683=5.7, P<.001) compared with CTC participants. Conclusions: CTC was feasible for delivering cessation support but was not superior to a self-help guide in helping motivated young adults to quit smoking. CTC will benefit from further formative research to address satisfaction and usage. As smartphone apps may not serve as useful alternatives to printed self-help guides, there is a need to conduct further research to understand how digital mobile technology smoking cessation interventions for smoking cessation can be improved. Trial Registration: ClinicalTrials.gov NCT01983150; http://clinicaltrials.gov/ct2/show/NCT01983150 (Archived by WebCite at http://www.webcitation.org/6VGyc0W0i)This work was supported by a grant from Health Canada, Federal Tobacco Control Strategy (Agreement #: 6549-15-2011/8300125) and a grant from the Canadian Institutes of Health Research (Grant #: MOP-130303). NBB received salary support from the Canadian Cancer Society Research Institute (Grant #: 2011-701019 & Grant# 2017-704507)

    Collisional Evolution of Irregular Satellite Swarms: Detectable Dust around Solar System and Extrasolar Planets

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    Since the 1980's it has been becoming increasingly clear that the Solar System's irregular satellites are collisionally evolved. We derive a general model for the collisional evolution of an irregular satellite swarm and apply it to the Solar System and extrasolar planets. Our model reproduces the Solar System's complement of observed irregulars well, and suggests that the competition between grain-grain collisions and Poynting-Robertson (PR) drag helps set the fate of the dust. Because swarm collision rates decrease over time the main dust sink can change with time, and may help unravel the accretion history of synchronously rotating regular satellites that show brightness asymmetries. Some level of dust must be present on AU scales around the Solar System's giant planets, which we predict may be at detectable levels. We also predict whether dust produced by extrasolar circumplanetary swarms can be detected. The coronagraphic instruments on JWST will have the ability to detect the dust generated by these swarms, which are most detectable around planets that orbit at tens of AU from the youngest stars. Because the collisional decay of swarms is relatively insensitive to planet mass, swarms can be much brighter than their host planets and allow discovery of Neptune-mass planets that would otherwise remain invisible. This dust may have already been detected. The observations of the planet Fomalhaut b can be explained as scattered light from dust produced by the collisional decay of an irregular satellite swarm around a 10 Earth-mass planet. Such a swarm comprises about 5 Lunar masses worth of irregular satellites. Finally, we consider what happens if Fomalhaut b passes through Fomalhaut's main debris ring, which allows the circumplanetary swarm to be replenished through collisions with ring planetesimals. (abridged)Comment: accepted to MNRA
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