The graphene sheet versus the 2DEG: a relativistic Fano spin-filter via STM and AFM tips

We explore theoretically the density of states (LDOS) probed by an STM tip of 2D systems hosting an adatom and a subsurface impurity,both capacitively coupled to AFM tips and traversed by antiparallel magnetic fields. Two kinds of setups are analyzed, a monolayer of graphene and a two-dimensional electron gas (2DEG). The AFM tips set the impurity levels at the Fermi energy, where two contrasting behaviors emerge: the Fano factor for the graphene diverges, while in the 2DEG it approaches zero. As result, the spin-degeneracy of the LDOS is lifted exclusively in the graphene system, in particular for the asymmetric regime of Fano interference. The aftermath of this limit is a counterintuitive phenomenon, which consists of a dominant Fano factor due to the subsurface impurity even with a stronger STM-adatom coupling. Thus we find a full polarized conductance, achievable just by displacing vertically the position of the STM tip. To the best knowledge, our work is the first to propose the Fano effect as the mechanism to filter spins in graphene. This feature arises from the massless Dirac electrons within the band structure and allows us to employ the graphene host as a relativistic Fano spin-filter

Quality in management accounting: approach by activities in large companies

This study intends to contribute to the knowledge about the approach by activities, a management accounting method that promotes the quality of information. As specific objectives we have identified the following: to analyze the knowledge rate regarding the approach by activities, and identify whether there is a link between it and the financial officers’ characteristics; to analyze the utilization rate of the approach by activities, and the factors conditioning it; to analyze whether there is a link between a company’s features, and the use of the approach by activities. The data collection method used was the application of a survey to the financial officers of the largest Portuguese companies, which yielded 61 valid responses. The results found allowed us to conclude the following: the Time Driven Activity Based Costing is very little known and used in Portugal; there is a link between the knowledge of the approach by activities and the financial officers’ gender, age and educational background; there is a link between the use of the approach by activities and two company features: the legal form and the capital holding.info:eu-repo/semantics/acceptedVersio

Ocorrência do percevejo bronzeado em eucalipto.

Resumo

Institutional Impact of EVAR's Incorporation in the Treatment of Abdominal Aortic Aneurysm: a 12 Years' Experience Analysis

Introduction: Endovascular aneurysm repair (EVAR) was introduced as a less aggressive treatment of abdominal aortic aneurysms (AAA) for patients ineligible for open repair (OR). Objective: To analyze EVAR's incorporation impact in the treatment of infra-renal abdominal aortic aneurysms in our institution. Methods: A retrospective study of the patients with diagnostic of infra-renal AAA treated between December 2001 and December 2013 was performed. The choice between EVAR and OR was based on surgeon's experience, considering patient clinical risk and aneurysm's anatomical features. Patients treated by EVAR and by OR were analyzed. In each group, patient's and aneurysm's characteristics, surgical and anesthesia times, cost, transfusion rate, intraoperative complications, hospital stay, mortality and re-intervention rates and survival curves were evaluated. Results: The mean age, all forms of heart disease and chronic renal failure were more common in EVAR group. Blood transfusion, surgical and anesthesia times and mean hospital stay were higher for OR. Intraoperative complications rate was higher for endovascular aneurysm repair, overall during hospitalization complication rate was higher for open repair. The average cost in endovascular aneurysm repair was 1448.3€ higher. Re-interventions rates within 30 days and late re-intervention were 4.1% and 11.7% for endovascular aneurysm repair versus 13.7% and 10.6% for open repair. Conclusions: Two different groups were treated by two different techniques. The individualized treatment choice allows to achieve a mortality of 2.7%. Age ≥80 years influences survival curve in OR group and ASA ≥IV in EVAR group. We believe EVAR's incorporation improved the results of OR itself. Patients with more comorbidities were treated by endovascular aneurysm repair, decreasing those excluded from treatment. Late reinterventions were similar for both techniques.info:eu-repo/semantics/publishedVersio

Escore de condição corporal e sua aplicação no manejo reprodutivo de ruminantes.

bitstream/CPPSE-2009/18301/1/CircularTecnica57.pd