8,384 research outputs found
Synthesis and characterization of nanocomposites based on polyaniline-gold/graphene nanosheets
Metallic phase in stoichiometric CeOBiS 2 revealed by space-resolved ARPES
Recently CeOBiS2 system without any fluorine doping is found to show superconductivity posing question on its origin. Using space resolved ARPES we have found a metallic phase embedded in the morphological defects and at the sample edges of stoichiometric CeOBiS2. While bulk of the sample is semiconducting, the embedded metallic phase is characterized by the usual electron pocket at X point, similar to the Fermi surface of doped BiS2-based superconductors. Typical size of the observed metallic domain is larger than the superconducting correlation length of the system suggesting that the observed superconductivity in undoped CeOBiS2 might be due to this embedded metallic phase at the defects. The results also suggest a possible way to develop new systems by manipulation of the defects in these chalcogenides with structural instability
Assessment and Management of Suicide Risk in Primary Care
Abstract
Background
Risk assessment and management of suicidal patients is emphasized as a key component of care in specialist mental health services, but these issues are relatively unexplored in primary care services.
Aim
To examine risk assessment and management in primary and secondary care in a clinical sample of individuals who were in contact with mental health services and died by suicide.
Method
Data collection from clinical proformas, case records, and semi-structured face–to-face interviews with general practitioners.
Results
Primary and secondary care data was available for 198 of the 336 cases (59%). The overall agreement in the rating of risk between services was poor (overall kappa = 0.127; p = 0.10). Depression, care setting (post discharge), suicidal ideation at last contact and a history of self-harm were associated with a rating of higher risk. Suicide prevention policies were available in 25% of primary care practices and 33% of staff received training in suicide risk assessments.
Conclusion
Risk is difficult to predict, but the variation in risk assessment between professional groups may reflect poor communication. Further research is required to understand this. There appears to be a relative lack of suicide risk assessment training in primary care
Coexistence of localized and itinerant electrons in BaFe2X3 (X = S and Se) revealed by photoemission spectroscopy
We report a photoemission study at room temperature on BaFe2X3 (X = S and Se)
and CsFe2Se3 in which two-leg ladders are formed by the Fe sites. The Fe 2p
core-level peaks of BaFe2X3 are broad and exhibit two components, indicating
that itinerant and localized Fe 3d sites coexist similar to KxFe2-ySe2. The Fe
2p core-level peak of CsFe2Se3 is rather sharp and is accompanied by a
charge-transfer satellite. The insulating ground state of CsFe2Se3 can be
viewed as a Fe2+ Mott insulator in spite of the formal valence of +2.5. The
itinerant versus localized behaviors can be associated with the stability of
chalcogen p holes in the two-leg ladder structure.Comment: 5 pages, 5 figures, Accepted in publication for Physical Review
Statefinder -- a new geometrical diagnostic of dark energy
We introduce a new cosmological diagnostic pair called
Statefinder. The Statefinder is dimensionless and, like the Hubble and
deceleration parameters and , is constructed from the scale factor
of the Universe and its derivatives only. The parameter forms the next
step in the hierarchy of geometrical cosmological parameters used to study the
Universe after and , while the parameter is a linear combination
of and chosen in such a way that it does not depend upon the dark
energy density . The Statefinder pair is
algebraically related to the the dark energy pressure-to-energy ratio
and its time derivative, and sheds light on the nature of dark
energy/quintessence. Its properties allow to usefully differentiate between
different forms of dark energy with constant and variable , including a
cosmological constant (). The Statefinder pair can be determined to
very good accuracy from a SNAP type experiment.Comment: 7 pages, 3 figures. Final version to be published in JETP Lett.,
presentation shortened, references added and updated, consideration of brane
cosmological models included, conclusions unchange
Decolonising quantitative research methods pedagogy: teaching contemporary politics to challenge hierarchies from data
Decolonisation of the curriculum in higher education is a radical, transformative process of change that interrogates the enduring Eurocentric and racist narratives surrounding the production of academic ‘knowledge’. Our key argument is that it is essential for students of politics to understand the authorities and hierarchies exerted through quantitative data. In this paper, we show that (1) quantitative methods and data literacy can be an explicit tool in the endeavour to challenge structures of oppression, and (2) there is a need to apply decolonial principles to the teaching of quantitative methods, prioritising the historical contextualisation and anti-racist critique of the ways in which statistics amplify existing micro and macro power relations. To explain how this can be done, we begin with a commentary on the ‘state of decolonisation’ in higher education, its relevance to the sub-disciplines of politics, and its application to quantitative teaching in the UK. We then suggest some guiding principles for a decolonial approach to quantitative methods teaching, and present substantive examples from political sociology, international political economy, and international development. These suggestions and examples show how a decolonial lens advances critical and emancipatory thinking in undergraduate students of politics when it is used with quantitative methods
Response of distance measures to the equation of state
We show that the distance measures (such as the luminosity and angular
diameter distances) are linear functionals of the equation-of-state function
w(z) of the dark energy to a fair degree of accuracy in the regimes of
interest. That is, the distance measures can be expressed as a sum of (i) a
constant and (ii) an integral of a weighting function multiplied by the
equation of state parameter w(z). The existence of such an accurate linear
response approximation has several important implications: (a) Fitting a
constant w model to the data drawn from an evolving model has a simple
interpretation as a weighted average of w(z). (b) Any polynomial (or other
expansion coefficients can also be expressed as weighted sums of the true w(z).
(c) A replacement for the commonly used heuristic equation for the effective
w(z), as determined by the CMB, can be derived and the result is found to be
quite close to the heuristic expression commonly used. (d) The reconstruction
of w(z) by Huterer et al. (2002) can be expressed as a matrix inversion. In
each case the limitations of the linear response approximation are explored and
found to be surprisingly small.Comment: 6 pages, 5 figures, minor changes, accepted to MNRA
Te 5p orbitals bring three-dimensional electronic structure to two-dimensional Ir0.95Pt0.05Te2
We have studied the nature of the three-dimensional multi-band electronic
structure in the twodimensional triangular lattice Ir1-xPtxTe2 (x=0.05)
superconductor using angle-resolved photoemission spectroscopy (ARPES), x-ray
photoemission spectroscopy (XPS) and band structure calculation. ARPES results
clearly show a cylindrical (almost two-dimensional) Fermi surface around the
zone center. Near the zone boundary, the cylindrical Fermi surface is truncated
into several pieces in a complicated manner with strong three-dimensionality.
The XPS result and the band structure calculation indicate that the strong Te
5p-Te 5p hybridization between the IrTe2 triangular lattice layers is
responsible for the three-dimensionality of the Fermi surfaces and the
intervening of the Fermi surfaces observed by ARPES.Comment: 5 pages, 4 figure
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