135 research outputs found
Transport, magnetic, and structural properties of LaCeMnO thin films. Evidence for hole-doping
Cerium-doped manganite thin films were grown epitaxially by pulsed laser
deposition at C and oxygen pressure Pa and were
subjected to different annealing steps. According to x-ray diffraction (XRD)
data, the formation of CeO as a secondary phase could be avoided for
Pa. However, transmission electron microscopy shows the presence
of CeO nanoclusters, even in those films which appear to be single phase in
XRD. With O annealing, the metal-to-insulator transition temperature
increases, while the saturation magnetization decreases and stays well below
the theoretical value for electron-doped LaCeMnO with mixed
Mn/Mn valences. The same trend is observed with decreasing film
thickness from 100 to 20 nm, indicating a higher oxygen content for thinner
films. Hall measurements on a film which shows a metal-to-insulator transition
clearly reveal holes as dominating charge carriers. Combining data from x-ray
photoemission spectroscopy, for determination of the oxygen content, and x-ray
absorption spectroscopy (XAS), for determination of the hole concentration and
cation valences, we find that with increasing oxygen content the hole
concentration increases and Mn valences are shifted from 2+ to 4+. The
dominating Mn valences in the films are Mn and Mn, and only a
small amount of Mn ions can be observed by XAS. Mn and Ce
XAS signals obtained in surface-sensitive total electron yield mode are
strongly reduced in the bulk-sensitive fluorescence mode, which indicates
hole-doping in the bulk for those films which do show a metal-to-insulator
transition.Comment: 8 pages, 10 figure
YBaCuO/LaCaMnO bilayers: Interface coupling and electric transport properties
Heteroepitaxially grown bilayers of ferromagnetic LaCaMnO
(LCMO) on top of superconducting YBaCuO (YBCO) thin films were
investigated by focusing on electric transport properties as well as on
magnetism and orbital occupation at the interface. Transport measurements on
YBCO single layers and on YBCO/LCMO bilayers, with different YBCO thickness
and constant LCMO thickness \,nm, show a significant reduction of
the superconducting transition temperature only for \,nm,with
only a slightly stronger suppression in the bilayers, as compared to the
single layers. X-ray magnetic circular dichroism (XMCD) measurements confirm
recently published data of an induced magnetic moment on the interfacial Cu by
the ferromagnetically ordered Mn ions, with antiparallel alignment between Cu
and Mn moments. However, we observe a significantely larger Cu moment than
previously reported, indicating stronger coupling between Cu and Mn at the
interface. This in turn could result in an interface with lower transparency,
and hence smaller spin diffusion length, that would explain our electric
transport data, i.e.smaller suppression. Moreover, linear dichroism
measurements did not show any evidence for orbital reconstruction at the
interface, indicating that a large change in orbital occupancies through
hybridization is not necessary to induce a measurable ferromagnetic moment on
the Cu atoms.Comment: 8 Figure
An analysis of photoemission and inverse photoemission spectra of Si(111) and sulphur-passivated InP(001) surfaces
Photoemission (PES) and inverse-photoemission spectra (IPES) for the
sulphur-passivated InP(001) surface are compared with theoretical predictions
based on density-functional calculations. As a test case for our methods, we
also present a corresponding study of the better known Si(111) surface. The
reported spectra for InP(001)-S agree well with the calculated ones if the
surface is assumed to consist of a mixture of two phases, namely, the fully
S-covered -reconstructed structure, which contains four S atoms in
the surface unit-cell, and a structure containing two S and two P
atoms per unit cell. The latter has recently been identified in total-energy
calculations as well as in core-level spectra of S-passivated
Si(111)- is in excellent agreement with the calculations. The
comparison of the experimental-PES with our calculations provides additional
considerations regarding the nature of the sample surface. It is also found
that the commonly-used density-of-states approximation to the photo- and
inverse- photoemission spectra is not valid for these systems.Comment: Submitted to Phys. Rev. B; 6 postscript formatted pages; 7 figures in
gif format; postscript figures available upon reques
F.A.R.O.G. FORUM, Vol. 4 No. 1
https://digitalcommons.library.umaine.edu/francoamericain_forum/1054/thumbnail.jp
Enabling nursing students to focus on the Ottawa Charter and the nurses role in tackling inequalities in health through international exchange
Student nurses in a transatlantic exchange program explored the role of registered nurses in five countries’ public health systems. The Ottawa Charter provided a framework for students to examine the nurse’s responsibilities in public health. Students took practice placements in geographically rural areas on another continent and explored inequalities in health care. If nurses are to understand their role in the health care system then they must be taught the scope of their practice including their role in health promotion, public health practice and community development. For this project nursing instructors developed an assignment relevant to the aims and suitable for students in all five nursing programs. Only three of 48 students offered an assignment which focused on building healthy public policy. Nurse educators need to explore this further to ensure nurses of the future are aware of their role and responsibilities in this area and have skills to work effectively to influence and build healthy policy. The international student exchange supported the students’ developing understanding of the breadth of initiatives around the globe where nurses are actively engaged in addressing inequalities of health. Findings from an analysis of their assignments are presented in this evaluative report
Low-value clinical practices in injury care: a scoping review and expert consultation survey
BACKGROUND: Tests and treatments that are not supported by evidence and could expose patients to unnecessary harm, referred to here as low-value clinical practices, consume up to 30% of healthcare resources. Choosing Wisely and other organisations have published lists of clinical practices to be avoided. However, few apply to injury and most are based uniquely on expert consensus. We aimed to identify low-value clinical practices in acute injury care. METHODS: We conducted a scoping review targeting articles, reviews and guidelines that identified low-value clinical practices specific to injury populations. Thirty-six experts rated clinical practices on a 5-point Likert scale from clearly low-value to clearly beneficial. Clinical practices reported as low-value by at least one level I, II or III study and considered clearly or potentially low-value by at least 75% of experts were retained as candidates for low-value injury care. RESULTS: Of 50,695 citations, 815 studies were included and led to the identification of 150 clinical practices. Of these 63 were considered candidates for low-value injury care; 33 in the emergency room, 9 in trauma surgery, 15 in the intensive care unit and 5 in orthopaedics. We also identified 87 'grey zone' practices, which did not meet our criteria for low-value care. CONCLUSIONS: We identified 63 low-value clinical practices in acute injury care that are supported by empirical evidence and expert opinion. Conditional on future research, they represent potential targets for guidelines, overuse metrics and de-implementation interventions. We also identified 87 'grey zone' practices, which may be interesting targets for value-based decision-making. Our study represents an important step towards the de-implementation of low-value clinical practices in injury care. LEVEL OF EVIDENCE: III
Spatiotemporal variability in pH and carbonate parameters on the Canadian Atlantic continental shelf between 2014 and 2022
The Atlantic Zone Monitoring Program (AZMP) was established by Fisheries and Oceans Canada (DFO) in 1998 with the aim of monitoring physical and biological ocean conditions in Atlantic Canada in support of fisheries management.
Since 2014, at least two of the carbonate parameters (pH; total alkalinity, TA; and dissolved inorganic carbon, DIC) have also been systematically measured as part of the AZMP, enabling the calculation of derived parameters (e.g., carbonate saturation states, Ω, and partial pressure of CO2, pCO2).
The present study gives an overview of the spatiotemporal variability in these parameters between 2014 and 2022.
Results show that the variability in the carbonate system reflects changes in both physical (e.g., temperature and salinity) and biological (e.g., plankton photosynthesis and respiration) parameters.
For example, most of the region undergoes a seasonal warming and freshening.
While the former will tend to increase Ω, the latter will decrease both TA and Ω.
Spring and summer plankton blooms decrease DIC near the surface and then remineralize and increase DIC at depth in the fall.
The lowest pCO2 values (down to ∼ 200 µatm) are located in the cold coastal Labrador Current, whereas the highest values (>1500 µatm) are found in the fresh waters of the Gulf of St. Lawrence and the St. Lawrence Estuary.
The latter is also host to the lowest pH values of the zone (7.48 in the fall of 2022).
Finally, most of the bottom waters of the Gulf of St. Lawrence (>90 %) are undersaturated with respect to aragonite (Ωarg<1).
In addition to providing a baseline of carbonate parameters for the Atlantic Zone as a whole, this comprehensive overview is a necessary and useful contribution for the modelling community and for more in-depth studies.
The full dataset of measured and derived parameters is available from the Federated Research Data Repository: https://doi.org/10.20383/102.0673 (Cyr et al., 2022a).</p
Le Forum, Vol. 44 #4
https://digitalcommons.library.umaine.edu/francoamericain_forum/1106/thumbnail.jp
Low-value clinical practices in adult traumatic brain injury : an umbrella review protocol
Introduction Traumatic brain injury (TBI) leads to 50 000 deaths, 85 000 disabilities and costs $60 billion each year in the USA. Despite numerous interventions and treatment options, the outcomes of TBI have improved little over the last three decades. In a previous scoping review and expert consultation survey, we identified 13 potentially low-value clinical practices in acute TBI. The objective of this umbrella review is to synthesise the evidence on potentially low-value clinical practices in the care of acute TBI.
Methods and analysis Using umbrella review methodology, we will search Cochrane Central Register of Controlled Trials, Embase, Epistemonikos, International Prospective Register of Systematic Reviews (PROSPERO) and PubMed to identify systematic reviews evaluating the effect of potential intrahospital low-value practices using tailored population, intervention, comparator, outcome and study design questions based on the results of a previous scoping review. We will present data on the methodological quality of these reviews (Assessing the Methodological Quality of Systematic Reviews-2), reported effect sizes and strength of evidence (Grading of Recommendations, Assessment, Development and Evaluation).
Ethics and dissemination Ethics approval is not required as original data will not be collected. Knowledge users from five healthcare quality organisations and clinical associations are involved in the design and conduct of the study. Results will be disseminated in a peer-reviewed journal, at international scientific meetings and to clinical, healthcare quality and patient–partner associations. This work will support the development of metrics to measure the use of low-value practices, inform policy makers on potential targets for deimplementation and in the long term reduce the use of low-value clinical practices in acute TBI care
Reply to: Concerns about estimating relative risk of death associated with convalescent plasma for COVID-19
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