Low-field microwave absorption and magnetoresistance in iron nanostructures grown by electrodeposition on n-type lightly-doped silicon substrates

In this study we investigate magnetic properties, surface morphology and crystal structure in iron nanoclusters electrodeposited on lightly-doped (100) n-type silicon substrates. Our goal is to investigate the spin injection and detection in the Fe/Si lateral structures. The samples obtained under electric percolation were characterized by magnetoresistive and magnetic resonance measurements with cycling the sweeping applied field in order to understand the spin dynamics in the as-produced samples. The observed hysteresis in the magnetic resonance spectra, plus the presence of a broad peak in the non-saturated regime confirming the low field microwave absorption (LFMA), were correlated to the peaks and slopes found in the magnetoresistance curves. The results suggest long range spin injection and detection in low resistive silicon and the magnetic resonance technique is herein introduced as a promising tool for analysis of electric contactless magnetoresistive samples.Comment: 12 pages, 5 figure

Online-learning at ISCTE-IUL: towards a sustainable education paradigm

Online-learning platforms have long been praised for their great benefits, such as the way they contribute to long-distance students being able to overcome geographical barriers to their education, and the way they allow students to self-manage, by autonomously deciding when they enroll and complete courses. This empowers people from all over the world to engage in lifelong-learning that may have an important impact in their daily lives, especially in developing countries. Besides these benefits, there’s also an important dimension that is often overlooked: the contribution that the use of online-learning platforms has in providing a sustainable environment by reducing environmentally-damaging effects and the use of scarce resources. In this paper, we present the economical and environmental impact that the use of an online-learning platform has had in a public University in Lisbon, Portugal. We first present the online-learning platform that was developed in-house and follow up by describing the positive impact that this education paradigm has had in the lives of students, in reducing costs at the University, and in contributing to a more sustainable future.info:eu-repo/semantics/acceptedVersio

Diagnóstico molecular de Pantoea ananatis em milho, sorgo e Digitaria sp.

A doença conhecida como mancha-branca-do-milho (MWS), inicialmente descrita como mancha-de-phaeosphaeria (PLS), é uma das principais doenças do milho no Brasil e vem crescendo em importância para os produtos em diferentes países. A identificação correta do agente etiológico é uma etapa importante para predição e manejo adequado da doença. O fungo Phaeosphaeria maydis foi inicialmente descrito como o agente etiológico dessa doença (Rane et al., 1966). Contudo, o insucesso na reprodução de sintomas, a ocorrência do fungo restrita a algumas áreas de cultivo do milho e sua ausência em áreas de elevada incidência da doença geraram sérias dúvidas sobre a etiologia da mesma. Assim, a realização de estudos científicos detalhados possibilitaram a identificação correta do agente causal da doença como sendo a bactéria Pantoea ananatis (Paccola-Meirelles et al., 2001). A partir dessa data, a doença passou a ser denominada mancha-branca-do-milho. O desenvolvimento de métodos diagnósticos simples, precisos e rápidos podem acelerar a tomada de decisões para controle da doença. Nesse documento é apresentado um método de diagnóstico que apresenta as características descritas anteriormente e que consiste no uso de apenas um par de iniciadores (primers) para amplificar uma região do cromossomo bacteriano que constitui uma assinatura genômica da espécie P. ananatis.bitstream/item/70056/1/doc-142-1.pd

Transformations of Heun's equation and its integral relations

We find transformations of variables which preserve the form of the equation for the kernels of integral relations among solutions of the Heun equation. These transformations lead to new kernels for the Heun equation, given by single hypergeometric functions (Lambe-Ward-type kernels) and by products of two hypergeometric functions (Erd\'elyi-type). Such kernels, by a limiting process, also afford new kernels for the confluent Heun equation.Comment: This version was published in J. Phys. A: Math. Theor. 44 (2011) 07520