399 research outputs found
Disorder effects in electronic structure of substituted transition metal compounds
Investigating LaNi(1-x)M(x)O3 (M = Mn and Fe), we identify a characteristic
evolution of the spectral function with increasing disorder in presence of
strong interaction effects across the metal-insulator transition. We discuss
these results vis-a-vis existing theories of electronic structure in
simultaneous presence of disorder and interaction.Comment: Revtex, 4 pages, 3 postscript figures (To appear in Phys. Rev. Lett
Patient advocacy: barriers and facilitators
BACKGROUND: During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among Iranian nurses. METHOD: This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. RESULTS: Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. CONCLUSION: Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in this study. It is concluded that advocacy is contextually complex, and is a controversial and risky component of the nursing practice. Further research is needed to determine the possibility of a correlation between identified barriers/ facilitators and the use of advocacy
IceCube - the next generation neutrino telescope at the South Pole
IceCube is a large neutrino telescope of the next generation to be
constructed in the Antarctic Ice Sheet near the South Pole. We present the
conceptual design and the sensitivity of the IceCube detector to predicted
fluxes of neutrinos, both atmospheric and extra-terrestrial. A complete
simulation of the detector design has been used to study the detector's
capability to search for neutrinos from sources such as active galaxies, and
gamma-ray bursts.Comment: 8 pages, to be published with the proceedings of the XXth
International Conference on Neutrino Physics and Astrophysics, Munich 200
Treatment with Natalizumab in Relapsing–Remitting Multiple Sclerosis Patients Induces Changes in Inflammatory Mechanism
Natalizumab is a widely accepted drug for the relapsing–remitting subtype of multiple sclerosis (RRMS). The present longitudinal exploratory study in RRMS patients analyzes the effects of natalizumab treatment on the levels of pro-inflammatory and anti-inflammatory cytokine protein levels and also the frequency and suppressor function of regulatory T cells. Flow cytometry was used to determine cytokines and regulatory T cell frequency while regulatory T cell suppressor function was assayed in vitro at different time-points after starting with natalizumab. Results showed serum levels of pro-inflammatory interferon gamma and interleukin (IL)-12p70, as well as anti-inflammatory IL-4 and IL-10, were elevated just a few hours or days after first IV infusion of natalizumab. Interestingly, other cytokines like IL-5 or IL-13 were also elevated while pro-inflammatory IL-17, IL-2, and IL-1β increased only after a long-term treatment, suggesting different immune mechanisms. In contrast, we did not observe any effect of natalizumab treatment on regulatory T cell frequency or activity. In conclusion, these results suggest natalizumab has other immunological effects beyond VLA-4 interaction and inhibition of CNS extravasation, the relevance of which is as yet unknown and warrants further investigation
Determining neutrino oscillation parameters from atmospheric muon neutrino disappearance with three years of IceCube DeepCore data
We present a measurement of neutrino oscillations via atmospheric muon
neutrino disappearance with three years of data of the completed IceCube
neutrino detector. DeepCore, a region of denser instrumentation, enables the
detection and reconstruction of atmospheric muon neutrinos between 10 GeV and
100 GeV, where a strong disappearance signal is expected. The detector volume
surrounding DeepCore is used as a veto region to suppress the atmospheric muon
background. Neutrino events are selected where the detected Cherenkov photons
of the secondary particles minimally scatter, and the neutrino energy and
arrival direction are reconstructed. Both variables are used to obtain the
neutrino oscillation parameters from the data, with the best fit given by
and
(normal mass hierarchy assumed). The
results are compatible and comparable in precision to those of dedicated
oscillation experiments.Comment: 10 pages, 7 figure
The IceCube Neutrino Observatory - Contributions to ICRC 2015 Part II: Atmospheric and Astrophysical Diffuse Neutrino Searches of All Flavors
Papers on atmospheric and astrophysical diffuse neutrino searches of all
flavors submitted to the 34th International Cosmic Ray Conference (ICRC 2015,
The Hague) by the IceCube Collaboration.Comment: 66 pages, 36 figures, Papers submitted to the 34th International
Cosmic Ray Conference, The Hague 2015, v2 has a corrected author lis
Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube
A diffuse flux of astrophysical neutrinos above has been
observed at the IceCube Neutrino Observatory. Here we extend this analysis to
probe the astrophysical flux down to and analyze its flavor
composition by classifying events as showers or tracks. Taking advantage of
lower atmospheric backgrounds for shower-like events, we obtain a shower-biased
sample containing 129 showers and 8 tracks collected in three years from 2010
to 2013. We demonstrate consistency with the
flavor ratio at Earth
commonly expected from the averaged oscillations of neutrinos produced by pion
decay in distant astrophysical sources. Limits are placed on non-standard
flavor compositions that cannot be produced by averaged neutrino oscillations
but could arise in exotic physics scenarios. A maximally track-like composition
of is excluded at , and a purely shower-like
composition of is excluded at .Comment: 8 pages, 3 figures. Submitted to PR
Search for Prompt Neutrino Emission from Gamma-Ray Bursts with IceCube
We present constraints derived from a search of four years of IceCube data
for a prompt neutrino flux from gamma-ray bursts (GRBs). A single
low-significance neutrino, compatible with the atmospheric neutrino background,
was found in coincidence with one of the 506 observed bursts. Although GRBs
have been proposed as candidate sources for ultra-high energy cosmic rays, our
limits on the neutrino flux disfavor much of the parameter space for the latest
models. We also find that no more than of the recently observed
astrophysical neutrino flux consists of prompt emission from GRBs that are
potentially observable by existing satellites.Comment: 15 pages, 3 figure
Measurement of the Atmospheric Spectrum with IceCube
We present a measurement of the atmospheric spectrum at energies
between 0.1 TeV and 100 TeV using data from the first year of the complete
IceCube detector. Atmospheric originate mainly from the decays of kaons
produced in cosmic-ray air showers. This analysis selects 1078 fully contained
events in 332 days of livetime, then identifies those consistent with particle
showers. A likelihood analysis with improved event selection extends our
previous measurement of the conventional fluxes to higher energies. The
data constrain the conventional flux to be times a
baseline prediction from a Honda's calculation, including the knee of the
cosmic-ray spectrum. A fit to the kaon contribution () to the neutrino
flux finds a kaon component that is times the baseline
value. The fitted/measured prompt neutrino flux from charmed hadron decays
strongly depends on the assumed astrophysical flux and shape. If the
astrophysical component follows a power law, the result for the prompt flux is
times a calculated flux based on the work by Enberg, Reno
and Sarcevic.Comment: PRD accepted versio
- …