1,323 research outputs found
Supply chain regulation in Scottish social care: facilitators and barriers
Drawing on a study of a Scottish government initiative to ensure the provision of a living wage to social care workers, the paper sheds new light on the value of regulating domestic supply chains to enhance labour standards in supplier organisations, and the factors that facilitate and hinder such regulation. The study confirms that supply chains driven by monopsonistic purchasers tend to drive down employment conditions, while indicating that the studied initiative met with a good deal of success due to a combination of the government generated ‘soft’ regulation and support from care providers that reflected both value and pragmatic considerations. It also highlights the contradictory tensions that can arise between policy aspirations and business objectives and suggests that to be effective, initiatives to enhance labour standards in supply chains need to address adverse market dynamics
Determining the stellar masses of submillimetre galaxies: the critical importance of star formation histories
Submillimetre (submm) galaxies are among the most rapidly star-forming and
most massive high-redshift galaxies; thus, their properties provide important
constraints on galaxy evolution models. However, there is still a debate about
their stellar masses and their nature in the context of the general galaxy
population. To test the reliability of their stellar mass determinations, we
used a sample of simulated submm galaxies for which we derived stellar masses
via spectral energy distribution (SED) modelling (with Grasil, Magphys, Hyperz
and LePhare) adopting various star formation histories (SFHs). We found that
the assumption of SFHs with two independent components leads to the most
accurate stellar masses. Exponentially declining SFHs (tau) lead to lower
masses (albeit still consistent with the true values), while the assumption of
single-burst SFHs results in a significant mass underestimation. Thus, we
conclude that studies based on the higher masses inferred from fitting the SEDs
of real submm galaxies with double SFHs are most likely to be correct, implying
that submm galaxies lie on the high-mass end of the main sequence of
star-forming galaxies. This conclusion appears robust to assumptions of whether
or not submm galaxies are driven by major mergers, since the suite of simulated
galaxies modelled here contains examples of both merging and isolated galaxies.
We identified discrepancies between the true and inferred stellar ages (rather
than the dust attenuation) as the primary determinant of the success/failure of
the mass recovery. Regardless of the choice of SFH, the SED-derived stellar
masses exhibit a factor of ~2 scatter around the true value; this scatter is an
inherent limitation of the SED modelling due to simplified assumptions.
Finally, we found that the contribution of active galactic nuclei does not have
any significant impact on the derived stellar masses.Comment: Accepted to A&A. 11 pages, 9 figures, 1 table. V2 main changes: 1)
discussion of the stellar age as the main parameter influencing the success
of an SED model (Fig. 4, 5, 7); 2) discussion of the age-dust degeneracy (Fig
9); 3) the comparison of real and simulated submm galaxies (Fig 1
Magnetostrictive and piezomagnetic properties of Tb1-xDyx Zn at low temperatures
Tb1-xDyxZn(0 axes can be changed to very hard \u3c100\u3e axes by increasing x from 0 to 1. (In fact, the existence of a near zero magnetic anisotropy by the proper choice of x is the origin of the well-known Terfenol-D alloys, Tb1-xDyxFe2). The Tb$1-x)DyxZn system discussed here is particularly attractive because of the simplicity of its crystal structure (CsCl), its relatively high Curie temperatures (for rare earth alloys), and the existence of a large (uv0) phase for T \u3c 50K. A summary of some of the important properties of these three alloy systems is given in Table I. In all these systems, at least one of the magnetostriction constraints is very large
Pollen feeding proteomics: Salivary proteins of the passion flower butterfly, Heliconius melpomene.
While most adult Lepidoptera use flower nectar as their primary food source, butterflies in the genus Heliconius have evolved the novel ability to acquire amino acids from consuming pollen. Heliconius butterflies collect pollen on their proboscis, moisten the pollen with saliva, and use a combination of mechanical disruption and chemical degradation to release free amino acids that are subsequently re-ingested in the saliva. Little is known about the molecular mechanisms of this complex pollen feeding adaptation. Here we report an initial shotgun proteomic analysis of saliva from Heliconius melpomene. Results from liquid-chromatography tandem mass-spectrometry confidently identified 31 salivary proteins, most of which contained predicted signal peptides, consistent with extracellular secretion. Further bioinformatic annotation of these salivary proteins indicated the presence of four distinct functional classes: proteolysis (10 proteins), carbohydrate hydrolysis (5), immunity (6), and "housekeeping" (4). Additionally, six proteins could not be functionally annotated beyond containing a predicted signal sequence. The presence of several salivary proteases is consistent with previous demonstrations that Heliconius saliva has proteolytic capacity. It is likely that these proteins play a key role in generating free amino acids during pollen digestion. The identification of proteins functioning in carbohydrate hydrolysis is consistent with Heliconius butterflies consuming nectar, like other lepidopterans, as well as pollen. Immune-related proteins in saliva are also expected, given that ingestion of pathogens is a likely route to infection. The few "housekeeping" proteins are likely not true salivary proteins and reflect a modest level of contamination that occurred during saliva collection. Among the unannotated proteins were two sets of paralogs, each seemingly the result of a relatively recent tandem duplication. These results offer a first glimpse into the molecular foundation of Heliconius pollen feeding and provide a substantial advance towards comprehensively understanding this striking evolutionary novelty.This work was supported by the Balfour-Browne Fund administered by the Department of Zoology at the University of Cambridge. Additional support came from the University of Kansas.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ibmb.2015.04.00
North Atlantic Intermediate to Deep Water circulation and chemical stratification during the past 1 Myr
Benthic foraminiferal carbon isotope records from a suite of drill sites in the North Atlantic are used to trace variations in the relative strengths of Lower North Atlantic Deep Water (LNADW), Upper North Atlantic Deep Water (UNADW), and Southern Ocean Water (SOW) over the past 1 Myr. During glacial intervals, significant increases in intermediate-to-deep δ13C gradients (commonly reaching >1.2‰) are consistent with changes in deep water circulation and associated chemical stratification. Bathymetric δ13C gradients covary with benthic foraminiferal δ18O and covary inversely with Vostok CO2, in agreement with chemical stratification as a driver of atmospheric CO2 changes. Three deep circulation indices based on δ13C show a phasing similar to North Atlantic sea surface temperatures, consistent with a Northern Hemisphere control of NADW/SOW variations. However, lags in the precession band indicate that factors other than deep water circulation control ice volume variations at least in this band
Energy Spectra of Reactor Neutrinos at KamLAND
The upcoming reactor neutrino experiment, KamLAND, has the ability to explore
the Large Mixing Angle (LMA) solution to the solar neutrino problem. Here, we
investigate the precision to which KamLAND should be able to measure these
parameters, utilizing the distortion of the energy spectrum of reactor
neutrinos. Incomplete knowledge of the fuel composition of the reactors will
lead to some error on this measurement. We estimate the size of this effect.Comment: 7 pages, 7 figures. References added. Minor changes in wordin
Racial/Ethnic Patterns in Prostate Cancer Outcomes in an Active Surveillance Cohort
Introduction. Concern regarding overtreatment of prostate cancer (CaP) is leading to increased attention on active surveillance (AS). This study examined CaP survivors on AS and compared secondary treatment patterns and overall survival by race/ethnicity. Methods. The study population consisted of CaP patients self-classified as black or white followed on AS in the Center for Prostate Disease Research (CPDR) multicenter national database between 1989 and 2008. Secondary treatment included radical prostatectomy (RP), external beam radiation therapy or brachytherapy (EBRT-Br), and hormone therapy (HT). Secondary treatment patterns and overall survival were compared by race/ethnicity. Results. Among 886 eligible patients, 21% were black. Despite racial differences in risk characteristics and secondary treatment patterns, overall survival was comparable across race. RP following AS was associated with the longest overall survival. Conclusion. Racial disparity in overall survival was not observed in this military health care beneficiary cohort with an equal access to health care
- …