Direct absorption imaging of ultracold polar molecules

We demonstrate a scheme for direct absorption imaging of an ultracold ground-state polar molecular gas near quantum degeneracy. A challenge in imaging molecules is the lack of closed optical cycling transitions. Our technique relies on photon shot-noise limited absorption imaging on a strong bound-bound molecular transition. We present a systematic characterization of this imaging technique. Using this technique combined with time-of-flight (TOF) expansion, we demonstrate the capability to determine momentum and spatial distributions for the molecular gas. We anticipate that this imaging technique will be a powerful tool for studying molecular quantum gases.Comment: 4 pages, 4 figure

Delimitação de áreas de preservação permanente em topos de morros para o território brasileiro.

O código florestal brasileiro defini como áreas de proteção permanente (APPs) os topos dos morros. Estes foram regulamentados pela resolução CONAMA 303/2002, que estabelece que o terço superior de morros e montanhas, cuja elevação ultrapasse 50 m e declividade seja superior a 30% , devam ser protegidos. Porém, a delimitação de tais áreas de forma automatizada e em grande escalas mostra-se um desafio, uma vez que a definição da base dos morros, na resolução CONAMA, pode ser questionada. Além disso, muitas metodologias propostas baseiam-se fortemente na interferência de um analista, resultando em problemas relacionados à interpretação e experiência do operador. Utilizando metodologia previamente e testada, que dispensa a interferência de um analista, resultando em problemas relacionados à interferência de um operador na definição dos topos e bases dos morros, foi delimitada a área de APP em topo de morro e montanha, em escala compatível com 1:250.000. Constatou-se que aproximadamente 400 mil Km2 do território nacional se enquadram nesta definição

Avaliação de substratos alternativos para produção de mudas de alface em bandejas.

bitstream/CNPAB-2010/27149/1/cot024.pd

Extra polarization states of cosmological gravitational waves in alternative theories of gravity

Cosmological Gravitational Waves (GWs) are usually associated with the transverse-traceless part of the metric perturbations in the context of the theory of cosmological perturbations. These modes are just the usual polarizations `+' and `x' which appear in the general relativity theory. However, in the majority of the alternative theories of gravity, GWs can present more than these two polarization states. In this context, the Newman-Penrose formalism is particularly suitable for evaluating the number of non-null GW modes. In the present work we intend to take into account these extra polarization states for cosmological GWs in alternative theories of gravity. As an application, we derive the dynamical equations for cosmological GWs for two specific theories, namely, a general scalar-tensor theory which presents four polarization states and a massive bimetric theory which is in the most general case with six polarization states for GWs. The mathematical tool presented here is quite general, so it can be used to study cosmological perturbations in all metric theories of gravity.Comment: 26 pages, 1 figure. Accepted for publication in Classical and Quantum Gravity

Ensino e capacitação agroflorestal no Brasil: uma abordagem com enfase na região Amazônica.

Cópia de trabalho editado em CD-ROM

Observational Constraints on Visser's Cosmological Model

Theories of gravity for which gravitons can be treated as massive particles have presently been studied as realistic modifications of General Relativity, and can be tested with cosmological observations. In this work, we study the ability of a recently proposed theory with massive gravitons, the so-called Visser theory, to explain the measurements of luminosity distance from the Union2 compilation, the most recent Type-Ia Supernovae (SNe Ia) dataset, adopting the current ratio of the total density of non-relativistic matter to the critical density ($\Omega_m$) as a free parameter. We also combine the SNe Ia data with constraints from Baryon Acoustic Oscillations (BAO) and CMB measurements. We find that, for the allowed interval of values for $\Omega_m$, a model based on Visser's theory can produce an accelerated expansion period without any dark energy component, but the combined analysis (SNe Ia + BAO + CMB) shows that the model is disfavored when compared with $\Lambda$CDM model.Comment: 6 pages, 4 figure