4,201 research outputs found

    Numerical predictions of the shot peening process

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    On the theory of magnetic field dependence of heat conductivity in dielectric in isotropic model

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    Phonon polarization in a magnetic field is analyzed in isotropic model. It is shown, that at presence of spin-phonon interaction phonon possess circular polari-zation which causes the appearance of heat flux component perpendicular both to temperature gradient and magnetic field.Comment: 5 pages, 0 figure

    The concentration and origins of carboxylic acid groups in oil paint

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    Although the concentration of carboxylic acid (COOH) groups is crucial to understand oil paint chemistry, analytical challenges hindered COOH quantification in complex polymerised oil samples thus far. The concentration of COOH groups is important in understanding oil paint degradation because it drives the breakdown of reactive inorganic pigments to dissolve in the oil network and form metal carboxylates. The metal ions in such an ionomeric polymer network can exchange with saturated fatty acids to form crystalline metal soaps (metal complexes of saturated fatty acids), leading to serious problems in many paintings worldwide. We developed two methods based on ATR-FTIR spectroscopy to accurately estimate the COOH concentration in artificially aged oil paint models. Using tailored model systems composed of linseed oil, ZnO and inert filler pigments, these dried oil paints were found to contain one COOH group per triacylglycerol unit. Model systems based on a mixture of long chain alcohols showed that the calculated COOH concentration originates from side chain autoxidation at low relative humidity (RH). The influence of increasing RH and ZnO concentration on COOH formation was studied and high relative humidity conditions were shown to promote the formation of COOH groups. No significant ester hydrolysis was found under the conditions studied. Our results show the potential of quantitative analysis of oil paint model systems for aiding careful (re)evaluation of conservation strategies

    Variation at the capsule locus, cps, of mistyped and non-typable Streptococcus pneumoniae isolates

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    The capsule polysaccharide locus (cps) is the site of the capsule biosynthesis gene cluster in encapsulated Streptococcus pneumoniae. A set of pneumococcal samples and non-pneumococcal streptococci from Denmark, the Gambia, the Netherlands, Thailand, the UK and the USA were sequenced at the cps locus to elucidate serologically mistyped or non-typable isolates. We identified a novel serotype 33B/33C mosaic capsule cluster and previously unseen serotype 22F capsule genes, disrupted and deleted cps clusters, the presence of aliB and nspA genes that are unrelated to capsule production, and similar genes in the non-pneumococcal samples. These data provide greater understanding of diversity at a locus which is crucial to the antigenic diversity of the pathogen and current vaccine strategies

    The mass miniature chest radiography programme in Cape Town, South Africa, 1948 - 1994: The impact of active tuberculosis case finding

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    Background. Tuberculosis (TB) control programmes rely mainly on passive detection of symptomatic individuals. The resurgence of TB has rekindled interest in active case finding. Cape Town (South Africa) had a mass miniature radiography (MMR) screening programme from 1948 to 1994.Objective. To evaluate screening coverage, yield and secular trends in TB notifications during the MMR programme.Methods. We performed an ecological analysis of the MMR programme and TB notification data from the City of Cape Town Medical Officer of Health reports for 1948 - 1994.Results. Between 1948 and 1962, MMR screening increased to 12% of the population per annum with yields of 14 cases per 1 000 X-rays performed, accounting for >20% of total annual TB notifications. Concurrent with increasing coverage (1948 - 1965), TB case notification decreased in the most heavily TB-burdened non-European population from 844/100 000 population to 415/100 000. After 1966, coverage declined and TB notifications that initially remained stable (1967 - 1978) subsequently increased to 525/100 000. MMR yields remained low in the European population but declined rapidly in the non-European population after 1966, coincidental with forced removals from District 6. An inverse relationship between screening coverage and TB notification rates was observed in the non-European adult population. Similar secular trends occurred in infants and young children who were not part of the MMR screening programme.Conclusion. MMR of a high-burdened population may have significantly contributed to TB control and was temporally associated with decreased transmission to infants and children. These historical findings emphasise the importance of re-exploring targeted active case finding strategies as part of population TB control

    The Marketing Of Body Image: A Cross-Cultural Comparison Of Gender Effects In The U.S. And China

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    Recently, there has been increasing controversy about the use of extremely thin female models and extremely muscular male models in advertising and fashion campaigns.  While this practice has been studied extensively over time, it is again in the forefront as models with low body mass indexes are being kept off runways around the world.  While most consumers understand that these images are nearly unattainable, they do tend to compare themselves with these idealized images resulting in lower satisfaction with their own bodies and lower self-esteem.  While past research most often examines these feelings with respect to women, there is little research on the effect on men and their self-image.  Also, while this has primarily been a “western” problem, it is becoming a problem in “eastern” cultures as western images and advertising campaigns proliferate.  This study examines both U.S. and Chinese men and women’s perceptions of body image.  The findings show cultural differences between the U.S. and Chinese males and females.  The U.S. women were the most affected, while there was no difference by gender between the Chinese men and women.  However, as the Chinese culture becomes more influenced by western ideals, this trend in body image dissatisfaction should increase

    Entanglement between a diamond spin qubit and a photonic time-bin qubit at telecom wavelength

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    We report on the realization and verification of quantum entanglement between an NV electron spin qubit and a telecom-band photonic qubit. First we generate entanglement between the spin qubit and a 637 nm photonic time-bin qubit, followed by photonic quantum frequency conversion that transfers the entanglement to a 1588 nm photon. We characterize the resulting state by correlation measurements in different bases and find a lower bound to the Bell state fidelity of F = 0.77 +/- 0.03. This result presents an important step towards extending quantum networks via optical fiber infrastructure
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