2,036 research outputs found
A consideration of methods of determining the radiative characteristics of jet fires
The radiative characteristics of jet fires is usually expressed through the use of a fraction of heat radiated, which is primarily a property of the fuel being considered. It is generally determined from experimental data of incident radiation around a fire and then derived by using a model of the incident radiation in terms of the fraction of heat radiated. Popular approaches include the single point source model where the flame is represented by a single point usually located halfway along the flame, or use of an idealised flame shape, such as a cylinder or cone, and deriving the flame surface emissive power which is closely related to the fraction of heat radiated. However, these modelling approaches may provide erroneous results for the fraction of heat radiated if incident radiation data in the near-field is used, and the fraction of heat radiated derived using one modelling approach may not be applicable to another approach without some adjustment. This paper explores the inherent near-field and far-field behaviour of different modelling approaches and the resulting impact on the fraction of heat radiated derived from each modelling approach using incident radiation data. A weighted multi-point source approach model was found to replicate both near-field and far-field behaviour well and capable of deriving the true fraction of heat radiated. Four idealised shapes were considered and it was found that the true fraction of heat radiated would need to be adjusted for use with these models even in the far-field, and some shortcomings in near-field behaviour were identified, which would suggest that some weighting of the surface emissive power over different regions of the flame would be needed. Finally, an idealised shape with hemispherical point sources distributed over its surface was considered and this model behaved well in both the near-field and far-field
Can there be a science of psychology? Aristotleâs de Anima and the structure and construction of science
Half integer quantum Hall effect in high mobility single layer epitaxial graphene
The quantum Hall effect, with a Berry's phase of is demonstrated here
on a single graphene layer grown on the C-face of 4H silicon carbide. The
mobility is 20,000 cm/Vs at 4 K and ~15,000 cm/Vs
at 300 K despite contamination and substrate steps. This is comparable to the
best exfoliated graphene flakes on SiO and an order of magnitude larger
than Si-face epitaxial graphene monolayers. These and other properties indicate
that C-face epitaxial graphene is a viable platform for graphene-based
electronics.Comment: Some modifications in the text and figures, 7 pages, 2 figure
Vapour cloud explosions in a long congested region involving methane/hydrogen mixtures
A series of large scale vapour cloud explosions in a long congested region were conducted using methane/hydrogen mixtures. The congested region measured 3 m Ă 3 m Ă 18 m long and was preceded by a confined region which allowed an explosion flame with some initial flame speed and turbulence to be generated which then entered the congested region. During the experiments the flame speed and explosion overpressure were measured through the congested region. The hydrogen content in the methane/hydrogen mixture was varied from 0 to 50% by volume. A key objective was to determine factors that could lead to continued flame acceleration through the congested region, such as the hydrogen concentration, the initial flame speed entering the congestion and the level of congestion. The results are reported together with some detailed observations of the complex nature of pressure traces produced by explosion events of this type
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Haplotype analysis of common variants in the BRCA1 gene and risk of sporadic breast cancer
INTRODUCTION: Truncation mutations in the BRCA1 gene cause a substantial increase in risk of breast cancer. However, these mutations are rare in the general population and account for little of the overall incidence of sporadic breast cancer. METHOD: We used whole-gene resequencing data to select haplotype tagging single nucleotide polymorphisms, and examined the association between common haplotypes of BRCA1 and breast cancer in a nested case-control study in the Nurses' Health Study (1323 cases and 1910 controls). RESULTS: One haplotype was associated with a slight increase in risk (odds ratio 1.18, 95% confidence interval 1.02â1.37). A significant interaction (P = 0.05) was seen between this haplotype, positive family history of breast cancer, and breast cancer risk. Although not statistically significant, similar interactions were observed with age at diagnosis and with menopausal status at diagnosis; risk tended to be higher among younger, pre-menopausal women. CONCLUSIONS: We have described a haplotype in the BRCA1 gene that was associated with an approximately 20% increase in risk of sporadic breast cancer in the general population. However, the functional variant(s) responsible for the association are unclear
A polymorphism in the 3' untranslated region of the gene encoding prostaglandin endoperoxide synthase 2 is not associated with an increase in breast cancer risk: a nested case-control study
INTRODUCTION: Prostaglandins are integral components in the cellular response to inflammation, promoting cellular proliferation and angiogenesis. The enzyme responsible for the conversion of arachidonic acid to prostaglandins in response to inflammation is prostaglandin endoperoxide synthase 2/cyclo-oxygenase 2 (PTGS2/COX2). Polymorphisms in the PTGS2 gene have been associated with various diseases, including inflammatory bowel disease and cancer of the lung, colorectum, and breast. METHODS: We genotyped the five most common polymorphisms (rs20417, rs5277, rs20432, rs5275, and rs4648298) in the Nurses' Health Study (1,270 cases, 1,762 controls) to test the hypothesis that polymorphisms in PTGS2 are associated with breast cancer risk, using logistic regression analyses. The Nurses' Health Study 2 (317 cases, 634 controls) and Harvard Women's Health Study (702 cases, 703 controls) were used to further examine putative associations. RESULTS: The rs5275 polymorphism in the 3' untranslated region of the PTGS2 gene was associated with a decrease in breast cancer risk. We therefore genotyped this single-nucleotide polymorphism in the Nurses' Health Study 2 and Harvard Women's Health Study. Similar results were observed in these subsequent analyses, with no statistically significant heterogeneity in risk estimates between studies. In pooled analyses, women homozygous for the T allele at rs5275 had a 20% lower risk of breast cancer than those homozygous for the C allele (odds ratio 0.80, 95% confidence interval 0.66 to 0.97). CONCLUSION: Although this polymorphism may be associated with a decrease in breast cancer risk among Caucasian women, we provide strong evidence that it is not associated with an increased risk of breast cancer
Ensin oli manipuljatsija, vÀlissÀ news management ja lopulta suurta yleisöÀ vedettiin nenÀstÀ Miten vÀlikielen kautta kÀÀntÀminen vaikuttaa viestin vÀlittymiseen, tutkimus kotouttamisen ja vieraannuttamisen nÀkökulmasta
TÀssÀ tutkimuksessa tarkastellaan vÀlikielen kautta kÀÀntÀmistÀ ja sen vaikutusta tekstin sisÀltÀmÀn viestin vÀlittymiseen. Viestin vÀlittymistÀ tarkastellaan kotouttavan ja vieraannuttavan kÀÀnnösstrategian nÀkökulmasta.
KÀÀntÀminen on monikielistÀ viestintÀÀ, jossa liikutaan eri kielten ja kulttuurien vÀlillÀ. TÀssÀ tutkimuksessa kÀÀntÀmisen prosessia verrataan yksinkertaistettuun viestinnÀn prosessiin ja löydetÀÀn niille yhtymÀkohdat. ViestinnÀn kaaviosta muokataan omat versionsa kuvaamaan niin perinteistÀ kÀÀnnösprosessia, jossa on mukana kaksi kieltÀ ja kulttuuria, kuin myös vÀlikielen kautta kÀÀntÀmisen prosessia, jolloin mukana on kolme kieltÀ ja kulttuuria. TÀllöin on helppo huomata kuinka pitkÀn matkan viesti kulkee ennen kuin se pÀÀtyy alkuperÀisen tekstin kirjoittajalta lopulliselle lukijalle.
Tutkimuksen aineistona kÀytetÀÀn venÀlÀisen toimittajan Anna Politkovskajan artikkeleita ja niiden kÀÀnnöksiÀ englanniksi sekÀ pÀÀasiassa englanninkielisten kÀÀnnösten pohjalta tehtyjÀ suomenkielisiÀ kÀÀnnöksiÀ. KÀÀnnöksistÀ tutkitaan erityisesti kÀÀnnösprosessin aikana tehtyjÀ poistoja, lisÀyksiÀ, leksikaalisia muutoksia ja rakenteen muutoksia. TehtyjÀ muutoksia arvioidaan kotouttamisen ja vieraannuttamisen kÀÀnnösstrategioiden nÀkökulmasta: kotouttamisen nÀhdÀÀn parantavan viestin vÀlittymistÀ ja vieraannuttamisen heikentÀvÀn.
Aineistossa havaittiin huomattavasti enemmÀn piirteitÀ kotouttavasta kÀÀnnösstrategiasta, jolloin alkuperÀisen viestin voisi ajatella vÀlittyvÀn hyvin kÀÀnnösten lukijoille. Kuitenkin aineistosta löytyi useita keinoja, joilla tekstistÀ oli tehty alkuperÀistÀ tekstiÀ yksinkertaisempaa ja ilmaisultaan laimeampaa. TÀmÀ viittaa siihen, ettei alkuperÀisen tekstin viesti kuitenkaan vÀlittynyt kÀÀnnöksissÀ tÀydellisesti.
Asiasanat:kotouttaminen, monikielinen viestintÀ, vieraannuttaminen, viestin vÀlittyminen, vÀlikielen kautta kÀÀntÀmine
External perceptions of successful university brands
Branding in universities has become an increasingly topical issue, with some institutions committing substantial financial resources to branding activities. The particular characteristics of the sector present challenges for those seeking to build brands and it therefore seems to be timely and appropriate to investigate the common approaches of those institutions perceived as having successful brands.
This study is exploratory in nature, seeking to investigate how successfully UK universities brand themselves, whether they are distinct and if the sector overall communicates effectively. This is approached through examining the perspective of opinion formers external to universities but closely involved with the sector â a key stakeholder group in UK higher education
Overall, the researchâs exploratory nature aims to further the debate on effective branding in UK higher education.
The findings and conclusions identify some issues surrounding university branding activity; most UK universities were considered to be distinct from one another, but few were seen to have real fully formed brands. Although a number of institutions that were seen as having more âsuccessfulâ brands were identified, it was argued that whilst many UK universities communicate their brand well enough to key stakeholders, they fail to consistently do this across all audiences. It was also suggested that UK universities may concentrate on areas of perceived immediate strategic importance (in terms of branding) to an extent where others are neglected
The Mitochondrial A10398G Polymorphism, Interaction with Alcohol Consumption, and Breast Cancer Risk
Polymorphisms in the mitochondrial genome are hypothesized to be associated with risk of various diseases, including cancer. However, there has been conflicting evidence for associations between a common polymorphism in the mitochondrial genome (A10398G, G10398A in some prior reports) and breast cancer risk. Reactive oxygen species, a by-product of mitochondrial energy production, can lead to oxidative stress and DNA damage in both the mitochondria and their cells. Alcohol consumption, which may also lead to oxidative stress, is associated with breast cancer risk. Therefore, we hypothesized that polymorphisms in the mitochondrial genome interact with alcohol consumption to alter breast cancer risk. We genotyped the A10398G polymorphism in a case-control study nested within the Nurses' Health Study (NHS, 1,561 cases, 2,209 controls). We observed an interaction between alcohol consumption (yes/no) and A10398G on breast cancer risk (p-intâ=â0.03). The risk associated with alcohol consumption was limited to carriers of the 10398G allele (Odds Ratio 1.52, 95% Confidence Interval 1.10â2.08 comparing drinkers to non-drinkers). However, we were unable to replicate these findings in the Women's Health Study (WHS, 678 cases, 669 controls), although the power to detect this interaction in the WHS was low (powerâ=â0.57). Further examination of this interaction, such as sufficiently powered epidemiological studies of cancer risk or associations with biomarkers of oxidative stress, may provide further evidence for GxE interactions between the A10398G mitochondrial polymorphism and alcohol consumption on breast cancer risk
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