Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation

We study the recently proposed Lorentz-violating dispersion relation for fermions and show that it leads to two distinct cubic operators in the momentum. We compute the leading order terms that modify the non-relativistic equations of motion and use experimental results for the hyperfine transition in the ground state of the ${}^9\textrm Be^+$ ion to bound the values of the Lorentz-violating parameters $\eta_1$ and $\eta_2$ for neutrons. The resulting bounds depend on the value of the Lorenz-violating background four-vector in the laboratory frame.Comment: Revtex 4, four pages. Version to match the one to appear in Physical Review

Developing a quality assurance metric: a panoptic view

This article is a post-print of the published article that may be accessed at the link below. Copyright @ 2006 Sage Publications.There are a variety of techniques that lecturers can use to get feedback on their teaching - for example, module feedback and coursework results. However, a question arises about how reliable and valid are the content that goes into these quality assurance metrics. The aim of this article is to present a new approach for collecting and analysing qualitative feedback from students that could be used as the first stage in developing more reliable quality assurance metrics. The approach, known as the multi-dimensional crystal view, is based on the belief that individuals have different views on the benefits that the embedded process in a system can have on the behaviour of the system. The results of this study indicate that in the context of evaluation and feedback methods, the multi-dimensional approach appears to provide the opportunity for developing more effective student feedback mechanisms

Preparo e utilização de capins palhadas como substrato para cama na avicultura alternativa.

bitstream/item/59419/1/CUsersPiazzonDocuments32.pdfProjeto n. 16.00.30001-16

Identificação e descarte de poedeiras improdutivas.

bitstream/item/59416/1/CUsersPiazzonDocuments35.pdfProjeto n.16.00.30001-1

Resonant electron heating and molecular phonon cooling in single C60_{60} junctions

We study heating and heat dissipation of a single \c60 molecule in the junction of a scanning tunneling microscope (STM) by measuring the electron current required to thermally decompose the fullerene cage. The power for decomposition varies with electron energy and reflects the molecular resonance structure. When the STM tip contacts the fullerene the molecule can sustain much larger currents. Transport simulations explain these effects by molecular heating due to resonant electron-phonon coupling and molecular cooling by vibrational decay into the tip upon contact formation.Comment: Accepted in Phys. Rev. Let