6,469 research outputs found
Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation
Measurements of the two dimensional angular correlation of the
electron-positron annihilation radiation have been done in the past to detect
the momentum spin density and the Fermi surface. We point out that the momentum
spin density and the Fermi Surface of ferromagnetic metals can be revealed
within great detail owing to the large cancellation of the electron-positron
matrix elements which in paramagnetic multiatomic systems plague the
interpretation of the experiments. We prove our conjecture by calculating the
momentum spin density and the Fermi surface of the half metal CrO2, who has
received large attention due to its possible applications as spintronics
material
Theoretical Study on Coexistence of Ferromagnetism and Superconductivity
On the basis of a two-dimensional t-t' Hubbard model in ferromagnetic and
paramagnetic states, the triplet superconducting mechanism is investigated by
the third-order perturbation theory with respect to the on-site Coulomb
interaction U. In general, the superconducting state is more stable in the
paramagnetic state than in the ferromagnetic state. As a special case, the
dominant ferromagnetic superconductivity is obtained by the electron-electron
correlation between the electronlike majority and holelike minority bands.
Furthermore, it is pointed out that in some cases the two bands play an
essential role for the coexistence of superconductivity and ferromagnetism.Comment: 5 pages, 10 figure
Independent Work Placements As A Getway To The World Of Work
Small to Medium-sized Enterprises (SMEs), a wide range of other languages are used. Every language is an asset. The most commonly spoken languages across enterprises of all sizes in the UK are French, German and Spanish, the ..
Distance as a barrier to cancer diagnosis and treatment: Review of the literature
The burden of travel from a patient’s residence to health care providers is an important issue that can influence access to diagnosis and treatment ofcancer.Although several studies have shown that the travel burden can result in delays in diagnosis and treatment of many common cancers, its role appears underestimated in the treatment of patients in clinical practice. Therefore, we performed a review of the published data on the role of travel burden influencing four items: delay of diagnosis, adequate treatment of cancer, outcome, and quality of life of cancer patients. Forty-seven studies published up to December 2014 were initially identified. Twenty studies were excluded because they did not regard specifically the four items of our review.Twenty-seven studies formed the basis of our study and involved 716,153 patients. The associations between travel burden and (a) cancer stage at diagnosis (12 studies), (b) appropriate treatment (8 studies), (c) outcome (4 studies), and (d) quality of life (1 study) are reported. In addition, in two studies,therelationbetween travel burden and compliance with treatment was examined. The results of our review show that increasing travel requirements are associated with more advanced disease at diagnosis, inappropriatetreatment, aworse prognosis, and a worse quality of life. These results suggest that clinical oncologists should remember the specific travel burden problem for cancer patients, who often need health care services every week or every month for many years
The dual nature of 5f electrons and origin of heavy fermions in U compounds
We develop a theory for the electronic excitations in UPt which is based
on the localization of two of the electrons. The remaining electron is
delocalized and acquires a large effective mass by inducing intra-atomic
excitations of the localized ones. The measured deHaas-vanAlphen frequencies of
the heavy quasiparticles are explained as well as their anisotropic heavy mass.
A model calculation for a small cluster reveals why only the largest of the
different hopping matrix elements is operative causing the electrons in
other orbitals to localize.Comment: 6 pages, 3 figure
Positron-electron autocorrelation function study of E-center in silicon
A study was conducted on the positron-electron autocorrelation function of defect center in silicon. The positron annihilation lifetime spectroscopy (PALS) spectra taken on the as-grown and defected samples of silicon were studied. It was found that the positron binding energy to the defect could be estimated from the ratio of the positron-electron autocorrelates for bulk crystal and defect trapped positron states.published_or_final_versio
Parental Distress and Affective Perception of Hospital Environment after a Pictorial Intervention in a Neonatal Intensive Care Unit
Pictorial humanization is a useful intervention for the improvement of hospitalized patients' affective states. Despite benefits in many hospital wards having been well documented, so far, no attention was paid to the Neonatal Intensive Care Unit (NICU). The aim of the present study was to evaluate the levels of distress and the affective perception of the environment experienced by parents of infants hospitalized in a NICU after the implementation of an intervention of pictorial humanization. A sample of 48 parents was recruited, 25 before the intervention was performed (Control Group), and 23 after its implementation (Pictorial Humanization Group). All parents completed the "Rapid Stress Assessment Scale" and "Scales of the Affective Quality Attributed to Place" questionnaires. Despite results showing no significant differences on parental distress, after implementation of pictorial intervention parents reported a perception of the NICU as significantly more pleasant, exciting, and arousing, and less distressing, unpleasant, gloomy, and sleepy. A higher level of distress and a perception of the environment as less relaxing was predicted for the Control Group condition. The present study suggests that the pictorial intervention represents a useful technique to create more welcoming hospital environments and to reduce the negative effects associated with infant hospitalization
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