Giant magnetic enhancement in Fe/Pd films and its influence on the magnetic interlayer coupling

The magnetic properties of thin Pd fcc(001) films with embedded monolayers of Fe are investigated by means of first principles density functional theory. The induced spin polarization in Pd is calculated and analyzed in terms of quantum interference within the Fe/Pd/Fe bilayer system. An investigation of the magnetic enhancement effects on the spin polarization is carried out and its consequences for the magnetic interlayer coupling are discussed. In contrast to {\it e.g.} the Co/Cu fcc(001) system we find a large effect on the magnetic interlayer coupling due to magnetic enhancement in the spacer material. In the case of a single embedded Fe monolayer we find aninduced Pd magnetization decaying with distance $n$ from the magnetic layer as ~$n^{-\alpha}$ with $\alpha \approx 2.4$. For the bilayer system we find a giant magnetic enhancement (GME) that oscillates strongly due to interference effects. This results in a strongly modified magnetic interlayer coupling, both in phase and magnitude, which may not be described in the pure Ruderman-Kittel-Kasuya-Yoshida (RKKY) picture. No anti-ferromagnetic coupling was found and by comparison with magnetically constrained calculations we show that the overall ferromagnetic coupling can be understood from the strong polarization of the Pd spacer

Oscillatory Exchange Coupling and Positive Magnetoresistance in Epitaxial Oxide Heterostructures

Oscillations in the exchange coupling between ferromagnetic $La_{2/3}Ba_{1/3}MnO_3$ layers with paramagnetic $LaNiO_3$ spacer layer thickness has been observed in epitaxial heterostructures of the two oxides. This behavior is explained within the RKKY model employing an {\it ab initio} calculated band structure of $LaNiO_3$, taking into account strong electron scattering in the spacer. Antiferromagnetically coupled superlattices exhibit a positive current-in-plane magnetoresistance.Comment: 4 pages (RevTeX), 5 figures (EPS

A simplified (modified) Duke Activity Status Index (M-DASI) to characterise functional capacity: A secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) study

Background Accurate assessment of functional capacity, a predictor of postoperative morbidity and mortality, is essential to improving surgical planning and outcomes. We assessed if all 12 items of the Duke Activity Status Index (DASI) were equally important in reflecting exercise capacity. Methods In this secondary cross-sectional analysis of the international, multicentre Measurement of Exercise Tolerance before Surgery (METS) study, we assessed cardiopulmonary exercise testing and DASI data from 1455 participants. Multivariable regression analyses were used to revise the DASI model in predicting an anaerobic threshold (AT) >11 ml kg −1 min −1 and peak oxygen consumption (VO 2 peak) >16 ml kg −1 min −1, cut-points that represent a reduced risk of postoperative complications. Results Five questions were identified to have dominance in predicting AT>11 ml kg −1 min −1 and VO 2 peak>16 ml.kg −1min −1. These items were included in the M-DASI-5Q and retained utility in predicting AT>11 ml.kg −1.min −1 (area under the receiver-operating-characteristic [AUROC]-AT: M-DASI-5Q=0.67 vs original 12-question DASI=0.66) and VO 2 peak (AUROC-VO2 peak: M-DASI-5Q 0.73 vs original 12-question DASI 0.71). Conversely, in a sensitivity analysis we removed one potentially sensitive question related to the ability to have sexual relations, and the ability of the remaining four questions (M-DASI-4Q) to predict an adequate functional threshold remained no worse than the original 12-question DASI model. Adding a dynamic component to the M-DASI-4Q by assessing the chronotropic response to exercise improved its ability to discriminate between those with VO 2 peak>16 ml.kg −1.min −1 and VO 2 peak<16 ml.kg −1.min −1. Conclusions The M-DASI provides a simple screening tool for further preoperative evaluation, including with cardiopulmonary exercise testing, to guide perioperative management

Integration of the Duke Activity Status Index into preoperative risk evaluation: a multicentre prospective cohort study.

BACKGROUND: The Duke Activity Status Index (DASI) questionnaire might help incorporate self-reported functional capacity into preoperative risk assessment. Nonetheless, prognostically important thresholds in DASI scores remain unclear. We conducted a nested cohort analysis of the Measurement of Exercise Tolerance before Surgery (METS) study to characterise the association of preoperative DASI scores with postoperative death or complications. METHODS: The analysis included 1546 participants (≥40 yr of age) at an elevated cardiac risk who had inpatient noncardiac surgery. The primary outcome was 30-day death or myocardial injury. The secondary outcomes were 30-day death or myocardial infarction, in-hospital moderate-to-severe complications, and 1 yr death or new disability. Multivariable logistic regression modelling was used to characterise the adjusted association of preoperative DASI scores with outcomes. RESULTS: The DASI score had non-linear associations with outcomes. Self-reported functional capacity better than a DASI score of 34 was associated with reduced odds of 30-day death or myocardial injury (odds ratio: 0.97 per 1 point increase above 34; 95% confidence interval [CI]: 0.96-0.99) and 1 yr death or new disability (odds ratio: 0.96 per 1 point increase above 34; 95% CI: 0.92-0.99). Self-reported functional capacity worse than a DASI score of 34 was associated with increased odds of 30-day death or myocardial infarction (odds ratio: 1.05 per 1 point decrease below 34; 95% CI: 1.00-1.09), and moderate-to-severe complications (odds ratio: 1.03 per 1 point decrease below 34; 95% CI: 1.01-1.05). CONCLUSIONS: A DASI score of 34 represents a threshold for identifying patients at risk for myocardial injury, myocardial infarction, moderate-to-severe complications, and new disability

Management of asymptomatic, well-differentiated PNETs: results of the Delphi consensus process of the Americas Hepato-Pancreato-Biliary Association.

BACKGROUND: Variation in the management of PNETs exist due to the limited high-level evidence to guide clinical practice. The aim of this work is to generate consensus guidelines with a Delphi process for managing PNETs. METHODS: A panel of experts reviewed the surgical literature and scored a set of clinical case statements using a web-based survey to identify areas of agreement and disagreement. Results of the survey were discussed after each round of review. This cycle was repeated until no further likelihood of reaching consensus existed. RESULTS: Twenty-two case statements related to surgical indications, preoperative biopsy, extent of resection, type of surgery, and tumor location were scored. Using a pre-defined definition of consensus, the panel achieved consensus on the following: i) resection is not recommended forlesions; ii) resection is recommended for lesions greater than 2 cm; iii) lymph node dissection is recommended for radiographically-suspicious nodes with splenectomy for distal lesions; iv) tumor enucleation and central pancreatectomy are acceptable when technically feasible. No consensus was reached regarding issues of preoperative biopsy or 1-2 cm tumors. CONCLUSIONS: Using a structured, validated system for identifying consensus, an expert panel identified areas of agreement regarding critical management decisions for patients with PNET. Issues without consensus warrant additional clinical investigation

Gilbert Damping in Single and Multilayer Ultrathin Films: Role of Interfaces in Nonlocal Spin Dynamics

Unique features of the Gilbert damping in magnetic multilayers were investigated by ferromagnetic resonance (FMR) using magnetic single and double layer structures prepared by molecular beam epitaxy. The FMR linewidth for the Fe films in the double layer structures was larger than the FMR linewidth in the single Fe films having the same thickness. The additional FMR linewidth scaled inversely with the film thickness, and increased linearly with increasing microwave frequency. These results demonstrate that a transfer of electron angular momentum between the magnetic layers leads to additional relaxation torques

Manejo da irrigação utilizando sensor da umidade do solo alternativo Irrigation scheduling using alternative soil moisture sensor

Um sensor alternativo utilizando a medida da capacitância para determinação da umidade do solo foi desenvolvido e calibrado em laboratório, e avaliado por meio da comparação com tensiômetros, no manejo da irrigação da cultura do feijoeiro. Utilizou-se um delineamento inteiramente casualizado com 5 repetições e esquema fatorial com dois métodos de manejo (alternativo e tensiometria) além tensões de água no solo (20, 40 e 60 kPa). Observou-se que, independente do método empregado, a produção do feijoeiro foi maior quando submetido a tensão de 39 kPa; entretanto, o manejo da irrigação utilizando-se o método alternativo levou a um número maior de irrigações e também do volume de água aplicado, com consequente redução da eficiência do uso da água em comparação com o uso de tensiômetros.<br>An alternative sensor using a capacitance measurement for determining soil moisture was developed and calibrated in the laboratory and evaluated by comparison with tensiometers in the irrigation of common bean. A completely randomized design was used with five replications and a factorial with two methods of management (alternative and tensiometer) and soil water tensions (20, 40 and 60 kPa). It was observed that regardless of the method, the bean yield was higher when subjected to stress of 39 kPa, however, irrigation management using the alternative method led to a greater number of irrigation and also the volume of water applied, with consequent reduction in water use efficiency compared to the use of tensiometers