6,511 research outputs found

    Theoretical Study on Coexistence of Ferromagnetism and Superconductivity

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    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

    Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation

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    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

    Independent Work Placements As A Getway To The World Of Work

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    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 ..

    Adherence to the mediterranean diet in association with self-perception of diet sustainability, anthropometric and sociodemographic factors: A cross-sectional study in italian adults

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    The adoption of sustainable dietary models, such as the Mediterranean Diet (MD), can be a valuable strategy to preserve ecosystems and human health. This study aims to investigate in an Italian adult representative sample the adherence to the MD and to what extent it is associated with the self-perceived adoption of a sustainable diet, the consideration of the MD as a sustainable dietary model, and anthropometric and sociodemographic factors. By applying an online survey (n = 838, 18–65 years, 52% female), an intermediate level of MD adherence (median: 4.0, IR: 3.0–4.0) in a 0–9 range was observed. Only 50% of the total sample confirmed the MD as a sustainable dietary model, and 84% declared no or low perception of adopting a sustainable diet. Being female, having a higher income and education level, considering the MD as a sustainable dietary model, as well as the perception of having a sustainable diet were the most relevant factors influencing the probability of having a high score (≥6) of adherence to the MD. This study suggests a gradual shift away from the MD in Italy and supports the need to address efforts for developing intervention strategies tailored to adults for improving diet quality. Furthermore, a public campaign should stress the link between a diet and its environmental impact to foster nutritionally adequate and eco-friendly dietary behaviors

    Parental Distress and Affective Perception of Hospital Environment after a Pictorial Intervention in a Neonatal Intensive Care Unit

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    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

    The skulls of Borgo Cerreto (Perugia): medical, surgical, and anatomical activity of Baronio Vincenzi (XVII century)

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    In the Sixties of the last century the vault of a 17th century private chapel was opened, revealing three isolated skulls with evidence of surgical and anatomical activity. The chapel was built by Baronio Vincenzi, who lived and practiced medicine in Borgo Cerreto, a village in the province of Perugia, between the 16th and the 17th century. The skull bc 01 belongs to an adult male, aged 25-35 years. It shows a hole on the left front-parietal region (30 x 31 mm), that can be identified as the result of a skull trepanation. The margins of the lesion are regularly smoothed and inclined internally and the diplopic tissues result almost completely obliterated by a cicatricial bone. A bone splinter (10 x 8 mm), completely reabsorbed, can be observed on the right side of the hole. These findings are the proof of a long survival of the subject. X-ray examination confirms a regular process of ossification, without infection. Trepanation was performed with a Hippocratic trypanon, largely used in cranial surgery of Modern Age. The specimen bc 02 is without skullcap and the right upper part of the face; it belongs to an adult male, 25-30 years aged. The cuts were produced by a bone saw with a thin blade. The choice of these regions suggests the willingness to study the basal skull, the right eye cavity and the paranasal sinuses. The skull bc 03 consists only in a skullcap of an adult individual, which shows the signs of a bone saw. In conclusion, the recovery of a trepanned skull, at present the first specimen of this type recovered so far in Umbria, together with two others skulls with the signs of postmortem examination, inside the Vincenzi family vault can be probably related to the professional activity of Baronio. He was an experienced surgeon and a skilled anatomist, who certainly experienced the empirical surgery of the nearby surgical School of Preci, famous throughout Europe for the treatment of urinary bladder stones, cataract as well as the ability in skull trepanation

    Kinetic comparison of tissue non-specific and placental human alkaline phosphatases expressed in baculovirus infected cells: application to screening for Down's syndrome

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    BACKGROUND: In humans, there are four alkaline phosphatases, and each form exibits a characteristic pattern of tissue distribution. The availability of an easy method to reveal their activity has resulted in large amount of data reporting correlations between variations in activity and illnesses. For example, alkaline phosphatase from neutrophils of mothers pregnent with a trisomy 21 fetus (Down's syndrome) displays significant differences both in its biochemical and immunological properties, and in its affinity for some specific inhibitors. RESULTS: To analyse these differences, the biochemical characteristics of two isozymes (non specific and placental alkaline phosphatases) were expressed in baculovirus infected cells. Comparative analysis of the two proteins allowed us to estimate the kinetic constants of denaturation and sensitivity to two inhibitors (L-p-bromotetramisole and thiophosphate), allowing better discrimination between the two enzymes. These parameters were then used to estimate the ratio of the two isoenzymes in neutrophils of pregnant mothers with or without a trisomy 21 fetus. It appeared that the placental isozyme represented 13% of the total activity of neutrophils of non pregnant women. This proportion did not significantly increase with normal pregnancy. By contrast, in pregnancies with trisomy 21 fetus, the proportion reached 60–80% of activity. CONCLUSION: Over-expression of the placental isozyme compared with the tissue-nonspecific form in neutrophils of mother with a trisomy 21 fetus may explain why the characteristics of the alkaline phosphatase in these cells is different from normal. Application of this knowledge could improve the potential of using alkaline phosphatase measurements to screen for Down's syndrome

    Spin moment over 10-300 K and delocalization of magnetic electrons above the Verwey transition in magnetite

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    In order to probe the magnetic ground state, we have carried out temperature dependent magnetic Compton scattering experiments on an oriented single crystal of magnetite (Fe3_3O4_4), together with the corresponding first-principles band theory computations to gain insight into the measurements. An accurate value of the magnetic moment μS\mu_S associated with unpaired spins is obtained directly over the temperature range of 10-300K. μS\mu_S is found to be non-integral and to display an anomalous behavior with the direction of the external magnetic field near the Verwey transition. These results reveal how the magnetic properties enter the Verwey energy scale via spin-orbit coupling and the geometrical frustration of the spinel structure, even though the Curie temperature of magnetite is in excess of 800 K. The anisotropy of the magnetic Compton profiles increases through the Verwey temperature TvT_v and indicates that magnetic electrons in the ground state of magnetite become delocalized on Fe B-sites above TvT_v.Comment: 5 pages, 5 figures, to appear in Journal of Physics and Chemistry of Solid

    Fermi Surface as the Driving Mechanism for Helical Antiferromagnetic Ordering in Gd-Y Alloys

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    The first direct experimental evidence for the Fermi surface (FS) driving the helical antiferromagnetic ordering in a gadolinium-yttrium alloy is reported. The presence of a FS sheet capable of nesting is revealed, and the nesting vector associated with the sheet is found to be in excellent agreement with the periodicity of the helical ordering.Comment: 4 pages, 4 figure
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