29 research outputs found

    Ferrimagnetism in sputtered MnxCoGe thin films

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    Investigations into the magnetic properties of sputtered MnxCoGe films in the range 0.8 <= x <= 2.5 uncovered ferrimagnetic order, unlike the ferromagnetic order reported in bulk samples. These films formed hexagonal Ni2In-type structures in all measured compositions. While the Curie temperatures of the films are comparable to those of hexagonal bulk MnCoGe, here is a reduction in the magnetization of the MnxCoGe film relative to bulk MnCoGe, and a magnetization compensation point is observed in the x < 1 samples. To understand the behavior, we calculated the magnetic moments of Mn-antisite defects in MnCoGe with density-function theory calculations. Models constructed from the calculation suggest that films become ferrimagnetic due to the presence of Mn on the Co and Ge sites. In the x < 1 samples, these defects arose from the disorder in the films, whereas for x > 1, the excess Mn was driven onto the antisites and produced ferrimagnetic order.Comment: 8 pages, 7 figure

    Giant anomalous Hall effect in epitaxial Mn3.2_{3.2}Ge films with a cubic kagome structure

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    We report on the first example of epitaxial Mn3+δ_{3 + δ}Ge thin films with a cubic L12L1_2 structure. The films are found to exhibit frustrated ferromagnetism with an average magnetization corresponding to 0.98 ± ~\pm~0.06 μB~μ_B/Mn, far larger than the parasitic ferromagnetism in hexagonal Mn3_3Ge and the partially compensated ferrimagnetism in tetragonal Mn3_3Ge. The Hall conductivity is the largest reported for the kagome magnets with a low temperature value of σxy=1587 σ_{xy} = 1587~S/cm. Density functional calculations predict that a chiral antiferromagnetic structure is lower in energy than a ferromagnetic configuration in an ordered stoichiometric crystal. However, chemical disorder driven by the excess Mn in our films explains why a frustrated 120^\circ spin structure is not observed. Comparisons between the magnetization and the Hall resistivity indicate that a non-coplanar spin structure contributes the Hall signal. Anisotropic magnetoresistance and planar Hall effect with hysteresis up to 14 T provides further insights into this material

    Adherence and profile of non-persistence in patients treated for osteoporosis—a large-scale, long-term retrospective study in The Netherlands

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    We analyzed 12-month compliance for all ten oral osteoporosis drugs in the Netherlands by medication possession ratio (MPR a parts per thousand yenaEuro parts per thousand 80%) in 105,506 patients, and persistence in 8,626 starters indicated high MPR (91%), low persistence (43%), and no restart in 78% of the stoppers after 18 months. We studied compliance and persistence for all available oral osteoporosis medications on a national scale in the Netherlands. We analyzed the IMS Health's longitudinal prescription database, which represents 73% of all pharmacies in the Netherlands. Twelve-month compliance was measured by medication possession ratio (MPR) in a cross-sectional cohort of 105,506 patients who received at least three prescriptions. Twelve-month persistence (no gap in refills for > 6 months) was measured in all 8,626 consecutive patients starting therapy, with a further follow-up in non-persistent patients during an additional 18 months for evaluation of switching, restart, or definitive stopping oral medication. Multivariate logistic regression analysis was used to analyze the odds ratios (ORs) with 95% confidence intervals (CI) of characteristics of non-persistence. MPR of a parts per thousand yen80% was found in 91% of patients. Persistence was 43% (range, 29-52%). Persistence was related to age > 60 years (ORs, 1.41 to 1.64), pharmacy outside very dense urban area (ORs, 1.39 to 1.44), additional use of calcium and/or vitamin D supplementation (OR, 1.26 and CI, 1.13, 1.39) and use of glucocorticoids (OR, 0.65 and CI, 0.59, 0.72) or cardiovascular medication (OR, 0.88 and CI, 0.79, 0.97). Of non-persistent patients, 22% restarted within 18 months with oral osteoporosis drugs. One-year compliance for all available oral osteoporosis medications was high, but 1-year persistence was low. Most stoppers did not restart or switch during an additional 18-month follow-up. These data indicate a major failure to adequately treat patients at high risk for fractures in daily practice.Amgen provided funds to IMS for data analysis. The preparation of this article was not supported by external funding. J.C. Netelenbos and P.P. Geusens have no conflict of interest, including specific financial interest and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript. Buijs and Ypma are employees of IMS Health

    Persistence of weekly alendronate: a real-world study in Croatia

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    Long-term treatment of osteoporosis is required for optimal efficacy, but adherence to therapy is suboptimal with daily and weekly oral bisphosphonates. The aim of this study was to assess real-world persistence (long-term adherence) with weekly alendronate. Persistence data were collected according to World Health Organization criteria for the prior month and year for 102 consecutive patients with osteoporosis at three outpatient clinics in Croatia. Persistence was assessed using medication possession ratios (MPR). Adequate persistence was defined as sufficient medication supply to ensure antifracture efficacy (MPR >or=80%). Self-reported persistence data were compared with resupply prescription data from primary care physicians (PCPs). The effect of patient age, co-therapy, co-morbidity, and time since osteoporosis was diagnosed were evaluated. A diagnosis of osteoporosis was established 3.21+/-1.83 years prior for the 96 women and six men enrolled (mean age 66.92+/-8.05 years). During the previous year, 86.3% patients reported not missing any tablets. Age correlated with the number of missed tablets, with older patients missing more tablets (p=0.038). Patients with co-therapy (p=0.042) missed more tablets. PCPs reported that 65.7% of the patients were issued prescriptions for 52 tablets. A total of 68.7% had MPR >80%. Patients with rheumatoid arthritis did not impact MPR (p=0.936). Previous fractures or number of fractures were not associated with persistence (p>0.05). In Croatia, persistence was superior with weekly-administered alendronate than has been reported elsewhere, perhaps due to socio-cultural factors. Larger, longitudinal studies are needed to confirm these results

    Nestling vocalization development in the European Starling (Sturnus vulgaris)

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    1 online resource (29 p.) : illustrationsIncludes abstract.Includes bibliographical references (p. 26-29).Nestlings vocalize while begging to elicit food from parents, and although many studies examine their begging behaviour, surprisingly little is known about vocal development in nestling passerines. European Starlings (Sturnus vulgaris) are a cavity-nesting passerine commonly found in anthropogenic environments. Adult males are open-ended learners, increasing the complexity of their songs with age. The objective of my study was to determine the ontogeny of vocalizations in nestling European Starlings over the nestling period (0 to ~22 days old). Using spectrograms, I observed and catalogued their calls every four days during the period between hatching and fledging. I found that the largest variation in vocalizations occurred when the nestlings were 5 to 13 days of age, and not when they were older. Nestlings appear to have increased consistency in their vocalizations as they grow older and settle in to their voices. It was predicted that a larger variation in call types would occur in larger brood sizes, however it was determined that there was no correlation between brood size and number of call types
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