3,253 research outputs found
The role of magnetoplasmons in Casimir force calculations
In this paper we review the role of magneto plasmon polaritons in the Casimir
force calculations. By applying an external constant magnetic field a strong
optical anisotropy is induced on two parallel slabs reducing the reflectivity
and thus the Casimir force. As the external magnetic field increases, the
Casimir force decreases. Thus, with an an external magnetic field the Casimir
force can be controlled.The calculations are done in the Voigt configuration
where the magnetic field is parallel to the slabs. In this configuration the
reflection coefficients for TE and TM modes do not show mode conversion.Comment: contribution to QFEXT09, Norman, Oklahoma 200
A framework for interpreting experimental errors in VISIR
Students usually do errors while performing experiments. In traditional, hands-on labs, instructors are able to help students surpass those errors. In non-traditional labs, like virtual labs or simulations, the support is usually provided by built-in mechanisms that prevent erroneous actions or that provide some sort of online assistance. In remote labs, like the Virtual Instruments Systems in Reality (VISIR) remote lab, the same principle applies. This paper describes the very initial stage of a framework for interpreting experimental errors done in VISIR. It considers the course syllabus of electrical circuits and situates the work done till the moment, in relation to that syllabus. Future work is also addressed.Partially supported by the European Commission, through grant 561735-EPP-1-2015-1-PT-EPPKA2-CBHE-JP, and by the Foundation for Science and Technology Project, FCT UID/EQU/04730/2013.info:eu-repo/semantics/publishedVersio
The Mediterranean diet and micronutrient levels in depressive patients
Introduction: An inverse association between depression and some serum micronutrient levels (selenium, zinc, iron, magnesium, vitamin B and folic acid) has been reported. In addition, other studies reported that this micronutrient supplementation may improve depressed mood. The Mediterranean diet contains a sufficient amount of the micronutrients mentioned, although no study has reported an association between diet prescription and increased levels of them in depressive patients.
Objective: To examine the impact of dietary patterns recommendations on micronutrient levels in depressive patients.
Methods: 77 outpatients were randomly assigned either to the active (hygienic-dietary recommendations on diet, exercise, sleep, and sun exposure) or control group. Outcome measures were assessed before and after the six month intervention period.
Results: Serum selenium and zinc levels were slightly low at basal point and serum selenium was inversely correlated with severity of depression (r=-0.233; p=0.041). A better outcome of depressive symptoms was found in the active group. Nevertheless, no significant differences in micronutrient levels were observed after the Mediterranean diet pattern prescription, probably due to an insufficient adherence.
Conclusion: Selenium, zinc, iron, magnesium, vitamin B12 and folic acid serum levels didn`t increase in depressed patients after six months of the Mediterranean diet pattern prescription
Magnetically activated adhesives: towards on-demand magnetic triggering of selected polymerisation reactions
On-demand initiation of chemical reactions is becoming increasingly popular in many areas. The use of a magnetic field to trigger reactions is an intriguing concept, with vast potential in both research and industrial settings, though it remains a challenge as yet unsolved. Here we report the first example of on-demand magnetic activation of a polymerisation process using an anaerobic adhesive formulation as an example of this new approach toward triggering polymerisation reactions using an external magnetic field. Our strategy involves the use of a colloidal system comprising functional methacrylate ester monomers, peroxide and CuII-salt as polymerisation initiators and magnetic nanoparticles coated with an oxidising shell. This unique combination prevents reduction of the reactive transition metal (CuII) ion by the metal substrates (steel or aluminium) to be joined – hence inhibiting the redox radical initiated cationic polymerisation reaction and efficiently preventing adhesion. The polymerisation and corresponding adhesion process can be triggered by removal of the functional magnetic particles using a permanent external magnet either prior to formulation application or at the joint to be adhered, enabling the polymerisation to proceed through CuII-mediated reduction. This new approach enables on-demand magnetically-triggered reaction initiation and holds potential for a range of useful applications in chemistry, materials science and relevant industrial manufacturing
- …