603 research outputs found
A New Dental Superalloy System: V. Embrittling Phase Transformations
The σ phase is rich in Ta. When the Ta concentration is less than 14%, σ does not interfere with the slip mechanism; when the Ta concentration is more than 15%, σ interferes with the slip mechanism. The coherent α-Co 3Ta phase forms at Ta concentrations of less than 15%, whereas incoherent γ-Co 2Ta forms only at higher Ta concentrations. The interface between σ and the matrix is an important factor in the failure mechanism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67929/2/10.1177_00220345740530013301.pd
Relativistic Quark Spin Coupling Effects in the Nucleon Electromagnetic Form Factors
We investigate the effect of different forms of relativistic spin coupling of
constituent quarks in the nucleon electromagnetic form factors. The
four-dimensional integrations in the two-loop Feynman diagram are reduced to
the null-plane, such that the light-front wave function is introduced in the
computation of the form factors. The neutron charge form factor is very
sensitive to different choices of spin coupling schemes, once its magnetic
moment is fitted to the experimental value. The scalar coupling between two
quarks is preferred by the neutron data, when a reasonable fit of the proton
magnetic momentum is found.Comment: 13 pages, needs axodraw.ps and axodraw.sty for diagrams of Fig.
Modelling the habitat of the endangered Carpentarian Grasswren (Amytornis dorotheae): The importance of spatio-temporal habitat availability in a fire prone landscape
Species distribution modelling (SDM), a tool increasingly adopted to quantify geographic range size, often predicts species’ distributions as static. However, habitat availability may exhibit spatial and temporal variation when dynamic processes, such as fire, determine suitability. Static SDM approaches may not satisfactorily represent this dynamic process. We investigated the potential use of SDM to quantify dynamic habitat availability by applying the MaxEnt SDM technique to model the habitat of the Carpentarian Grasswren (Amytornis dorotheae), an endangered Australian passerine dependent on long unburnt vegetation in a fire prone system. By adjusting a typical SDM approach to incorporate the dynamic nature of fire, we modelled the spatio-temporal variation of suitable habitat over 12 years and compared it to a static modelling approach. Incorporating fire as a dynamic process increased the importance of the fire variable to models (from 35% permutation importance) and improved model performance, as evaluated by the AUC using cross-validation. Our dynamic model revealed sizeable temporal variation in the area and spatial arrangement of suitable habitat that was not apparent in the static model. This result may partly solve the mystery of why the species occurs as widely separated populations despite the presence of seemingly suitable intervening habitat. In areas where the species is no longer found, habitat availability was less consistent due to frequent fire, and fire refugia was more limited and isolated, when compared to sites with recent records. These results demonstrate that, when compared to a static approach, a dynamic SDM approach can lead to improved understanding of dynamic ecological processes, and their impact on a species
Do stronger school smoking policies make a difference? Analysis of the health behaviour in school-aged children survey
Background: Associations of the strength of school smoking policies with cigarette, e-cigarette and cannabis use in Wales were examined. Methods: Nationally representative cross-sectional survey of pupils aged 11–16 years (N=7376) in Wales. Senior management team members from 67 schools completed questionnaires about school smoking policies, substance use education and tobacco cessation initiatives. Multi-level, logistic regression analyses investigated self-reported cigarette, e-cigarette and cannabis use, for all students and those aged 15–16 years. Results: Prevalence of current smoking, e-cigarette use and cannabis use in the past month were 5.3%, 11.5% and 2.9%, respectively. Of schools that provided details about smoking policies (66/67), 39.4% were strong (written policy applied to everyone in all locations), 43.9% were moderate (written policy not applied to everyone in all locations) and 16.7% had no written policy. There was no evidence of an association of school smoking policies with pupils’ tobacco or e-cigarette use. However, students from schools with a moderate policy [OR = 0.47; 95% (confidence interval) CI: 0.26–0.84] were less likely to have used cannabis in the past month compared to schools with no written policy. This trend was stronger for students aged 15–16 years (moderate policy: OR = 0.42; 95% CI: 0.22–0.80; strong policy: OR = 0.45; 95% CI: 0.23–0.87). Conclusions: School smoking policies may exert less influence on young people’s smoking behaviours than they did during times of higher adolescent smoking prevalence. Longitudinal studies are needed to examine the potential influence of school smoking policies on cannabis use and mechanisms explaining this associatio
Observations on the distribution of serum uric acid levels in participants of the Tecumseh, Michigan, Community Health Studies : A comparison of results of one method used at two different times and of two methods used simultaneously
Individuals participating in the Tecumseh Community Health Study, in 1959-1960 (TCHS I) and 1962-1965 (TCHS II), had serum uric acid determinations by an enzymatic spectrophotometric method, SUA(ES), as part of a comprehensive health examination.Among the 1633 male and 1725 female subjects, the mean serum uric acid concentration had increased by 0.32 mg per 100 ml for males, and by 0.18 for females, over the the average of 4.1 yr between determinations. It was found that, approximately, 40 per cent of subjects had a decrease, and 56 per cent, an increase, in serum uric acid concentration. The change was greater than plus or minus 2.0 mg per 100 ml for 28.7 per cent of males and 19.4 per cent of females. Decreases of as much as 8.2, and increases of as much as 9.9 mg per 100 ml were observed. How much of the average increase, in an average 4.1 yr interval between tests, is due to ageing, except for males in the age range of 10-19 yr, is problematical. It seems probably that most of the average increase was due to technical factors in performance of the test.In the study of 1962-1965, serum uric acid determinations were done by two methods. An automated colorimetric method was compared with an enzymatic spectrophotometric method. Both methods showed the same types of distribution curves of serum uric acid concentrations and curves of age-sex specific mean serum uric acid.The values obtained by the automated colorimetric method were slightly, but, consistently, higher to a statistically significant degree than those of the enzymatic spectro-photometric method.For 2092 male subjects, the mean SUA(AC) was 0.21 mg per 100 ml greater than the mean SUA(ES), while for 2104 females subjects, this difference was 0.14.Of 4196 study subjects, whose sera were tested by both methods, about 90.0 per cent showed an agreement of the two values within +/- 0.9 mg per 100 ml. However, 1.9 per cent of males and 1.6 per cent of females, had ES values which exceeded AC values by 2.0 mg per 100 ml, while 2.8 per cent of male and 2.3 per cent of female subjects had AC values greater than ES values by 2.0 mg per 100 ml. The extremes of differences range from 4.4 to 7.3 mg per 100 ml.The data in this paper gives us increased confidence in the essential validity of the mean age and sex distributions of serum uric acid values, from the Tecumseh Community Health Studies, published in an earlier paper [2].It is concluded that, for the purposes of population studies, the automated colorimetric method is more advantageous than the enzymatic spectrophotometric method, because of its lesser cost.Comparison of the results of the two studies emphasizes the problems of definition of hyperuricemia. Further mathematical analysis of the distribution curves obtained in such studies may lead to definitions of normo- and hyperuricemia of greater precision for clinical purposes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32701/1/0000068.pd
Critical magnetic fluctuations induced superconductivity and residual density of states in superconductor
We propose the multiband extension of the spin-fermion model to address the
superconducting d-wave pairing due to magnetic interaction near critical point.
We solve the unrestricted gap equation with a general d-wave symmetry gap and
find that divergent magnetic correlation length leads to the very
unharmonic shape of the gap function with shallow gap regions near nodes. These
regions are extremely sensitive to disorder. Small impurity concentration
induces substantial residual density of states. We argue that we can understand
the large value and its pressure
dependence of the recently discovered superconductor under pressure
within this approach.Comment: 5 figure
Fermi Surface Measurements on the Low Carrier Density Ferromagnet Ca1-xLaxB6 and SrB6
Recently it has been discovered that weak ferromagnetism of a dilute 3D
electron gas develops on the energy scale of the Fermi temperature in some of
the hexaborides; that is, the Curie temperature approximately equals the Fermi
temperature. We report the results of de Haas-van Alphen experiments on two
concentrations of La-doped CaB6 as well as Ca-deficient Ca1-dB6 and
Sr-deficient Sr1-dB6. The results show that a Fermi surface exists in each case
and that there are significant electron-electron interactions in the low
density electron gas.Comment: 4 pages, 5 figures, submitted to PR
The Point of Origin of the Radio Radiation from the Unresolved Cores of Radio-Loud Quasars
Locating the exact point of origin of the core radiation in active galactic
nuclei (AGN) would represent important progress in our understanding of
physical processes in the central engine of these objects. However, due to our
inability to resolve the region containing both the central compact object and
the jet base, this has so far been difficult. Here, using an analysis in which
the lack of resolution does not play a significant role, we demonstrate that it
may be impossible even in most radio loud sources for more than a small
percentage of the core radiation at radio wavelengths to come from the jet
base. We find for 3C279 that percent of the core flux at 15 GHz must
come from a separate, reasonably stable, region that is not part of the jet
base, and that then likely radiates at least quasi-isotropically and is
centered on the black hole. The long-term stability of this component also
suggests that it may originate in a region that extends over many Schwarzschild
radii.Comment: 7 pages with 3 figures, accepted for publication in Astrophysics and
Space Scienc
Relativistic Quark Spin Coupling Effects in the Correlations Between Nucleon Electroweak Properties
We investigate the effect of different relativistic spin couplings of
constituent quarks on nucleon electroweak properties. Within each quark spin
coupling scheme the correlations between static electroweak observables are
found to be independent of the particular shape of the momentum part of the
nucleon light-front wave function. The neutron charge form factor is very
sensitive to different choices of spin coupling schemes once the magnetic
moment is fitted to the experimental value. However, it is found rather
insensitive to the details of the momentum part of the three-quark wave
function model.Comment: 23 pages, 13 figures, requires axodraw.sty 1 figure corrected, 1
refs. added, some changes in tex
Horizon Europe-New European Bauhaus Nexus Report: Conclusions of the High-Level Workshop on ‘Research and Innovation for the New European Bauhaus’, jointly organised by DG Research and Innovation and the Joint Research Centre
The ‘Horizon Europe-New European Bauhaus Nexus Report’ (2022) is an independent expert report. The report offers a set of guiding principles that can shape the goals and ambitions of the New European Bauhaus initiative. The recommendations aim to support the New European Bauhaus core values – sustainability, inclusion, and aesthetics. The recommendations are based on the current and future organisational structures and timeframes of the Horizon Europe research and innovation framework programme. They consider opportunities for the funding period 20212022, mid-term goals for the period 2023-2024, and long-term actions beyond 2024 that reflect the transdisciplinary and trans-sectoral vision of the New European Bauhaus. The report also provides a roadmap with strategic priorities and associated benchmarks that describe a possible path forward for European society and its response to the climate crisis, together with the EU’s global partners
- …