Superconducting proximity effect in the presence of strong spin scattering

We report measurements of the four terminal temperature dependent resistance of narrow Au wires implanted with ~100 ppm Fe impurities in proximity to superconducting Al films. The wires show an initial decrease in resistance as the temperature is lowered through the superconducting transition of the Al films, but then show an increase in resistance as the temperature is lowered further. In contrast to the case of pure Au wires in contact with a superconducting film, the resistance at the lowest temperatures rises above the normal state resistance. Analysis of the data shows that, in addition to contributions from magnetic scattering and electron-electron interactions, the temperature dependent resistivity shows a substantial contribution from the superconducting proximity effect, which exists even in the presence of strong spin scattering.Comment: 4 pages, 3 figure

Boundary controllability and source reconstruction in a viscoelastic string under external traction

Treatises on vibrations devote large space to study the dynamical behavior of an elastic system subject to known external tractions. In fact, usually a "system" is not an isolated body but it is part of a chain of mechanisms which disturb the "system" for example due to the periodic rotation of shafts. This kind of problem has been rarely studied in control theory. In the specific case we shall study, the case of a viscoelastic string, the effect of such external action is on the horizontal component of the traction, and so it affects the coefficients of the corresponding wave type equation, which will be time dependent. The usual methods used in controllability are not naturally adapted to this case. For example at first sight it might seem that moment methods can only be used in case of coefficients which are constant in time. Instead, we shall see that moment methods can be extended to study controllability of a viscoelastic string subject to external traction and in particular we shall study a controllability problem which is encountered in the solution of the inverse problem consisting in the identification of a distributed disturbance source

A MEMS viscometer for unadulterated human blood

The design and theoretical modelling of an oscillating micro-mechanical-viscometer designed for the measurement of whole unadulterated human blood, is described. The proposed device utilises the dependence of the squeeze-film damping ratio on properties of the surrounding fluid to measure fluid viscosity using an oscillating plate structure. The optimum geometrical configuration for the device structure has been investigated and a methodology for defining the optimum configuration of the micro-mechanical sensor identified. This is then applied to calculate the predicted noise equivalent viscosity change . It was found that the device performance is limited by electronic noise within the detection circuitry rather than thermal mechanical noise. An electronic noise limited measurement resolution of , is predicted for measurement over a shear range of , at a measurement bandwidth of . The linearity of response of the micro-mechanical-viscometer is considered and the device is predicted to provide a linear measurement response

Sample of LMXBs in the Galactic bulge. I. Optical and near-infrared constraints from the Virtual Observatory

We report on the archival optical and near-infrared observations of 6 low mass X-ray binaries situated in the Galactic bulge. We processed several recent Chandra and XMM-Newton as well as Einstein datasets of a binary systems suspected to be ultracompact, which gave us arcsec-scale positional uncertainty estimates. We then undertook comprehensive search in existing archives and other Virtual Observatory resources in order to discover unpublished optical/NIR data on these objects. We found and analysed data from ESO Archive and UKIRT Infrared Deep Sky Survey (UKIDSS) on SLX 1735-269, 3A 1742-294, SLX 1744-299, SLX 1744-300, GX 3+1, IGR J17505-2644 systems and publish their finding charts and optical flux constraints in this paper, as well as simple estimates of the physical parameters of these objects.Comment: 8 pages, 6 figures, 1 table; accepted for publication in MNRA

Comparative studies of the age-related changes in protein synthesis in the rat pancreas and parotid gland

This study was undertaken to determine whether changes occur in protein synthesis with age in the pancreas of the rat and to compare the pattern of changes with that observed in parotid salivary glands. The rate of incorporation of 3H-leucine into acid-insoluble proteins declines with age in both glands. In the pancreas, the rate of incorporation reaches the highest level at 12 months and declines by 21, 54 and 64% of this level at 18, 24 and 30 months, respectively. In parotid glands, the highest level of the amino acid incorporation occurs at 2 months and the level declines by 21, 29, 49 and 58% of the 2-month level at 12, 18, 24 and 30 months, respectively. There is no age-related difference in the rate of incorporation of 3H-leucine into acid-soluble fractions of the two glands. The cellular level of [alpha]-amylase is also reduced in the pancreas and parotid gland of old (24- and 30-month-old) rats. The differences in the cellular level of [alpha]-amylase activity among the age groups correlate with the differences in the number of secretory granules present in the acinar cells of the pancreas, indicating that the level of amylase reflects the cellular content of secretory proteins. There is no detectable morphological change that parallels the over 50% reduction in protein synthesis in these glands of young and old rats.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24504/1/0000781.pd

Elemental abundance differences in the 16 Cygni binary system: a signature of gas giant planet formation?

The atmospheric parameters of the components of the 16Cygni binary system, in which the secondary has a gas giant planet detected, are measured accurately using high quality observational data. Abundances relative to solar are obtained for 25 elements with a mean error of 0.023 dex. The fact that 16CygA has about four times more lithium than 16CygB is normal considering the slightly different masses of the stars. The abundance patterns of 16CygA and B, relative to iron, are typical of that observed in most of the so-called solar twin stars, with the exception of the heavy elements (Z>30), which can, however, be explained by Galactic chemical evolution. Differential (A-B) abundances are measured with even higher precision (0.018 dex, on average). We find that 16CygA is more metal-rich than 16CygB by 0.041+/-0.007 dex. On an element-to-element basis, no correlation between the A-B abundance differences and dust condensation temperature (Tc) is detected. Based on these results, we conclude that if the process of planet formation around 16CygB is responsible for the observed abundance pattern, the formation of gas giants produces a constant downwards shift in the photospheric abundance of metals, without a Tc correlation. The latter would be produced by the formation of terrestrial planets instead, as suggested by other recent works on precise elemental abundances. Nevertheless, a scenario consistent with these observations requires the convective envelopes of 1 Msun stars to reach their present-day sizes about three times quicker than predicted by standard stellar evolution models.Comment: ApJ, in pres

Is skin autofluorescence (SAF) representative of dermal advanced glycation endproducts (AGEs) in dark skin?:A pilot study

Aims: Non-invasively assessed skin autofluorescence (SAF) measures advanced glycation endproducts (AGEs) in the dermis. SAF correlates with dermal AGEs in Caucasians and Asians, but studies in dark-skinned subjects are lacking. In this pilot we aimed to assess whether SAF signal is representative of intrinsic fluorescence (IF) and AGE accumulation in dark skin. Methods: Skin biopsies were obtained in 12 dark-skinned subjects (6 healthy subjects, median age 22 years; 6 diabetes mellitus (DM) subjects, 65 years). SAF was measured with the AGE Reader, IF using confocal microscopy, and AGE distribution with specific antibodies. CML and MG-H1 were quantified with UPLC-MS/MS and pentosidine with HPLC and fluorescent detection. Results: SAF correlated with IF from the dermis (405nm, r = 0.58, p < 0.05), but not with CML (r = 0.54, p = 0.07). CML correlated with IF from the dermis (405nm, r = 0.90, p < 0.01). UV reflectance and the coefficient of variation of SAF were negatively correlated (r = -0.80, p < 0.01). CML and MG-H1 were predominantly present around blood vessels, in collagen and fibroblasts in the dermis. Conclusion: This proof of concept study is the first to compare non-invasive SAF with AGE levels measured in skin biopsies in dark-skinned subjects. SAF did not correlate with individual AGEs from biopsies, but was associated with IF. However, the intra-individual variance was high, limiting its application in dark-skinned subjects on an individual basis

Family involvement, employee engagement and employee performance in enterprising family firms

The study has been designed to analyze probable determinants of employee performance in family firms. A quantitative methodology was adopted. Data were collected from 113 employees from fifteen family businesses located in the Western Province in Sri Lanka. Correlation and ordinal logistic regression analysis were used to elaborate the relationships. Correlation analysis indicated that both family involvement and employee engagement correlate to employee performance. Family involvement in case of holding positions in functional and strategic levels by family members has shown no correlation to employee performance. Yet, having a family member as immediate boss/supervisor of an employee in the job has a strong correlation to employee performance. Regression analysis makes evident that almost all coefficients of the employee are negatively related to employee performance. Yet, all levels of employee engagement are significantly related to employee performance. It further shows that being the lower levels of employee engagement increases the likelihood of lower levels of employee performance. © 2017 Mendel University of Agriculture and Forestry Brno. All rights reserved

Who, where, when: the demographic and geographic distribution of bicycle crashes in West Yorkshire

Factors associated with cycle safety, including international differences in injury and mortality rates, protective equipment and bicycle training, have been subject to increasing academic interest. Environmental variables associated with cycle safety have also been scrutinised, but few studies have focussed on geographical factors at the local level. This paper addresses this research gap by analysing a geo-referenced dataset of road traffic incidents, taken from the UK's STATS19 dataset (2005 - 2012). We investigate incidents involving cyclists within West Yorkshire. This is an interesting case study area as it has an historically low cycling rate but very ambitions cycling plans following investment from the Department for Transport. West Yorkshire is found to be an unusually risky area for cyclists, with an estimated 53 deaths and 1372 serious injuries per billion kilometres cycled, based on census commuting statistics. This is roughly double the national average. This riskiness varies spatially and temporally, broadly in line with expectations from the previous literature. An unexpected result was that cycling seems to be disproportionately risky for young people in West Yorkshire compared with young people nationally. The case study raises the issue of potential negative health impacts of promoting cycling amongst vulnerable groups in dangerous areas. We conclude by highlighting opportunities for increasing cycling uptake via measures designed primarily to improve safety. The analysis underlying this research is reproducible, based on code stored at https://github.com/Robinlovelace/bikeR

Constraining cosmic scatter in the Galactic halo through a differential analysis of metal-poor stars

© ESO 2017.Context. The chemical abundances of metal-poor halo stars are important to understanding key aspects of Galactic formation and evolution. Aims. We aim to constrain Galactic chemical evolution with precise chemical abundances of metal-poor stars (−2.8 ≤ [Fe/H] ≤ −1.5). Methods. Using high resolution and high S/N UVES spectra of 23 stars and employing the differential analysis technique we estimated stellar parameters and obtained precise LTE chemical abundances. Results. We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba. The differential technique allowed us to obtain an unprecedented low level of scatter in our analysis, with standard deviations as low as 0.05 dex, and mean errors as low as 0.05 dex for [X/Fe]. Conclusions. By expanding our metallicity range with precise abundances from other works, we were able to precisely constrain Galactic chemical evolution models in a wide metallicity range (−3.6 ≤ [Fe/H] ≤ −0.4). The agreements and discrepancies found are key for further improvement of both models and observations. We also show that the LTE analysis of Cr II is a much more reliable source of abundance for chromium, as Cr I has important NLTE effects. These effects can be clearly seen when we compare the observed abundances of Cr I and Cr II with GCE models. While Cr I has a clear disagreement between model and observations, Cr II is very well modeled. We confirm tight increasing trends of Co and Zn toward lower metallicities, and a tight flat evolution of Ni relative to Fe. Our results strongly suggest inhomogeneous enrichment from hypernovae. Our precise stellar parameters results in a low star-to-star scatter (0.04 dex) in the Li abundances of our sample, with a mean value about 0.4 dex lower than the prediction from standard Big Bang nucleosynthesis; we also study the relation between lithium depletion and stellar mass, but it is difficult to assess a correlation due to the limited mass range. We find two blue straggler stars, based on their very depleted Li abundances. One of them shows intriguing abundance anomalies, including a possible zinc enhancement, suggesting that zinc may have been also produced by a former AGB companion.Peer reviewedFinal Published versio