Could face-centered cubic titanium in cold-rolled commercially-pure titanium only be a Ti-hydride?

A face-centered cubic (FCC) phase in electro-polished specimens for transmission electron microscopy of commercially pure titanium has sometimes been reported. Here, a combination of atom-probe tomography, scanning transmission electron microscopy and low-loss electron energy loss spectroscopy is employed to study both the crystal structural and chemical composition of this FCC phase. Our results prove that the FCC phase is actually a TiHx (x>1) hydride, and not a new allotrope of Ti, in agreement with previous reports. The formation of the hydride is discussed

On reductions of some KdV-type systems and their link to the quartic He'non-Heiles Hamiltonian

A few 2+1-dimensional equations belonging to the KP and modified KP hierarchies are shown to be sufficient to provide a unified picture of all the integrable cases of the cubic and quartic H\'enon-Heiles Hamiltonians.Comment: 12 pages, 3 figures, NATO ARW, 15-19 september 2002, Elb

Phase field modelling of stacking fault shear in nickel base superalloys

Stacking fault shear (SFS) is the dominant creep deformation mechanism in Nibase superalloys subjected to primary creep conditions (750°C, 800MPa). TEM observations1 have shown that the source of plastic strain is the shearing of they' precipitates by dislocation ribbons with overall burgers vector of a. SFS can only occur when they matrix is sufficiently saturated with a/2 dislocations. These matrix dislocations are unable to cut the y' because of the high energy APB they leave in their wake. By combining into a ribbon, shearing of the precipitates is facilitated by formation of intrinsic and extrinsic stacking faults (SISF and SESF)

Causes of variation in BCG vaccine efficacy: examining evidence from the BCG REVAC cluster randomized trial to explore the masking and the blocking hypotheses.

BCG protection varies and in some places (nearest the equator) is low or absent. Understanding this variation can inform the efforts to develop new vaccines against tuberculosis. Two main hypotheses are used to explain this variation: under masking, new vaccines are unlikely to increase protection; under blocking new vaccines have a greater potential to be effective when BCG is not. We conducted a cluster randomized trial to explored the masking and blocking hypotheses by studying BCG vaccine efficacy of neonatal vaccination and when administered for the first or a second (revaccination) time at school age in two sites (Manaus close and Salvador further south from the equator). Seven hundred and sixty three state schools were matched on socio economic characteristics of the neighborhood and 239,934 children were randomized to vaccine (BCG vaccination at school age) or control group. Protection by first BCG vaccination at school age was high in Salvador (34%, 95% CI 7-53%, p=0.017) but low in Manaus (8%, 95% CI t0 39-40%, p=0.686). For revaccination at school age, protection was modest in Salvador (19%, 95% CI 3-33%, p=0.022) and absent in Manaus (1%, 95% CI to 27-23%, p=0.932). Vaccine efficacy for neonatal vaccination was similar in Salvador (40%, 95% CI 22-54%, p<0.001) and Manaus (36%, 95% CI 11-53%, p=0.008). Variation in BCG efficacy was marked when vaccine was given at school age but absent at birth, which points towards blocking as the dominant mechanism. New tuberculosis vaccines that overcome or by pass this blocking effect could confer protection in situations where BCG is not protective

Nutrition, Diabetes and Tuberculosis in the Epidemiological Transition

BACKGROUND: Diabetes prevalence and body mass index reflect the nutritional profile of populations but have opposing effects on tuberculosis risk. Interactions between diabetes and BMI could help or hinder TB control in growing, aging, urbanizing populations. METHODS AND FINDINGS: We compiled data describing temporal changes in BMI, diabetes prevalence and population age structure in rural and urban areas for men and women in countries with high (India) and low (Rep. Korea) TB burdens. Using published data on the risks of TB associated with these factors, we calculated expected changes in TB incidence between 1998 and 2008. In India, TB incidence cases would have increased (28% from 1.7 m to 2.1 m) faster than population size (22%) because of adverse effects of aging, urbanization, changing BMI and rising diabetes prevalence, generating an increase in TB incidence per capita of 5.5% in 10 years. In India, general nutritional improvements were offset by a fall in BMI among the majority of men who live in rural areas. The growing prevalence of diabetes in India increased the annual number of TB cases in people with diabetes by 46% between 1998 and 2008. In Korea, by contrast, the number of TB cases increased more slowly (6.1% from 40,200 to 42,800) than population size (14%) because of positive effects of urbanization, increasing BMI and falling diabetes prevalence. Consequently, TB incidence per capita fell by 7.8% in 10 years. Rapid population aging was the most significant adverse effect in Korea. CONCLUSIONS: Nutritional and demographic changes had stronger adverse effects on TB in high-incidence India than in lower-incidence Korea. The unfavourable effects in both countries can be overcome by early drug treatment but, if left unchecked, could lead to an accelerating rise in TB incidence. The prevention and management of risk factors for TB would reinforce TB control by chemotherapy

Quantifying serum antibody in bird fanciers' hypersensitivity pneumonitis

BACKGROUND: Detecting serum antibody against inhaled antigens is an important diagnostic adjunct for hypersensitivity pneumonitis (HP). We sought to validate a quantitative fluorimetric assay testing serum from bird fanciers. METHODS: Antibody activity was assessed in bird fanciers and control subjects using various avian antigens and serological methods, and the titer was compared with symptoms of HP. RESULTS: IgG antibody against pigeon serum antigens, quantified by fluorimetry, provided a good discriminator of disease. Levels below 10 mg/L were insignificant, and increasing titers were associated with disease. The assay was unaffected by total IgG, autoantibodies and antibody to dietary hen's egg antigens. Antigens from pigeon serum seem sufficient to recognize immune sensitivity to most common pet avian species. Decreasing antibody titers confirmed antigen avoidance. CONCLUSION: Increasing antibody titer reflected the likelihood of HP, and decreasing titers confirmed antigen avoidance. Quantifying antibody was rapid and the increased sensitivity will improve the rate of false-negative reporting and obviate the need for invasive diagnostic procedures. Automated fluorimetry provides a method for the international standardization of HP serology thereby improving quality control and improving its suitability as a diagnostic adjunct

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223

We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B. We measured Delta_t(BC) = 7.8+/-0.8 days, Delta_t(BD) = -6.5+/-0.7 days and Delta_t_CD = -14.3+/-0.8 days. We spacially deconvolved HST NICMOS2 F160W images to derive accurate astrometry of the quasar images and to infer the light profile of the lensing galaxy. We combined these images with a stellar population fitting of a deep VLT spectrum of the lensing galaxy to estimate the baryonic fraction, $f_b$, in the Einstein radius. We measured f_b = 0.65+0.13-0.10 if the lensing galaxy has a Salpeter IMF and f_b = 0.45+0.04-0.07 if it has a Kroupa IMF. The spectrum also allowed us to estimate the velocity dispersion of the lensing galaxy, sigma_ap = 222+/-34 km/s. We used f_b and sigma_ap to constrain an analytical model of the lensing galaxy composed of an Hernquist plus generalized NFW profile. We solve the Jeans equations numerically for the model and explored the parameter space under the additional requirement that the model must predict the correct astrometry for the quasar images. Given the current error bars on f_b and sigma_ap, we did not constrain H0 yet with high accuracy, i.e., we found a broad range of models with chi^2 < 1. However, narrowing this range is possible, provided a better velocity dispersion measurement becomes available. In addition, increasing the depth of the current HST imaging data of HE 0435-1223 will allow us to combine our constraints with lens reconstruction techniques that make use of the full Einstein ring that is visible in this object.Comment: 12 pages, 10 figures, final version accepted for publication by A&

The pulsating hot subdwarf Balloon 090100001: results of the 2005 multisite campaign

We present the results of a multisite photometric campaign on the pulsating sdB star Balloon 090100001. The star is one of the two known hybrid hot subdwarfs with both long- and short-period oscillations. The campaign involved eight telescopes with three obtaining UBVR data, four B-band data, and one Stromgren uvby photometry. The campaign covered 48 nights, providing a temporal resolution of 0.36microHz with a detection threshold of about 0.2mmag in B-filter data. Balloon 090100001 has the richest pulsation spectrum of any known pulsating subdwarf B star and our analysis detected 114 frequencies including 97 independent and 17 combination ones. The strongest mode (f_1) in the 2.8mHz region is most likely radial while the remaining ones in this region form two nearly symmetric multiplets: a triplet and quintuplet, attributed to rotationally split \ell=1 and 2 modes, respectively. We find clear increases of splitting in both multiplets between the 2004 and 2005 observing campaigns, amounting to 15% on average. The observed splittings imply that the rotational rate in Bal09 depends on stellar latitude and is the fastest on the equator. We use a small grid of models to constrain the main mode (f_1), which most likely represents the radial fundamental pulsation. The groups of p-mode frequencies appear to lie in the vicinity of consecutive radial overtones, up to the third one. Despite the large number of g-mode frequencies observed, we failed to identify them, most likely because of the disruption of asymptotic behaviour by mode trapping. The observed frequencies were not, however, fully exploited in terms of seismic analysis which should be done in the future with a larger grid of reliable evolutionary models of hot subdwarfs.Comment: accepted for publication in MNRA

New members in the Upper Sco association from the UKIDSS Early Data Release

We present the results of a 9.3 square degree infrared (ZYJHK) survey in the Upper Scorpius association extracted from the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Cluster Survey Early Data Release. We have selected a total of 112 candidates from the ($Z-J$,$Z$) colour-magnitude diagram over the Z=12.5-20.5 magnitude range, corresponding to M = 0.25-0.01 Msun at an age of 5 Myr and a distance of 145 pc. Additional photometry in J and K filters revealed most of them as reddened stars, leaving 32 possible members. Among them, 15 have proper motion consistent with higher mass members from Hipparcos and optical spectra with strong Halpha in emission and weak gravity features. We have also extracted two lower mass candidate members for which no optical spectra are in hand. Three members exhibit strong Halpha equivalent widths (>20 Angstroms), suggesting that they could still undergo accretion whereas two other dwarfs show signs of chromospheric activity. The likelihood of the binarity of a couple of new stellar and substellar members is discussed as well.Comment: 12 pages, 6 figures, 5 tables, accepted to MNRA