Lifetimes of ultralong-range strontium Rydberg molecules in a dense BEC

The lifetimes and decay channels of ultralong-range Rydberg molecules created in a dense BEC are examined by monitoring the time evolution of the Rydberg population using field ionization. Studies of molecules with values of principal quantum number, $n$, in the range $n=49$ to $n=72$ that contain tens to hundreds of ground state atoms within the Rydberg electron orbit show that their presence leads to marked changes in the field ionization characteristics. The Rydberg molecules have lifetimes of $\sim1-5\,\mu$s, their destruction being attributed to two main processes: formation of Sr$^+_2$ ions through associative ionization, and dissociation induced through $L$-changing collisions. The observed loss rates are consistent with a reaction model that emphasizes the interaction between the Rydberg core ion and its nearest neighbor ground-state atom. The measured lifetimes place strict limits on the time scales over which studies involving Rydberg species in cold, dense atomic gases can be undertaken and limit the coherence times for such measurements.Comment: 9 pages, 8 figure

Tropical cyclone activity affected by volcanically induced ITCZ shifts

Volcanic eruptions can inject a large amount of aerosol particles, which interact with solar radiation and consequently can affect the climate worldwide, hence the intensity and frequency of extreme events for a few years following the eruption. However, only a handful of studies have investigated the impacts of volcanic eruptions on tropical cyclone activity. Through a set of sensitivity modeling experiments, our study demonstrates that volcanic eruptions by shifting the Intertropical convergence zone can impact tropical cyclone activity up to 4 years following the eruption. These results will prove valuable to society, allowing us to better prepare for the consequences of changes in tropical cyclone activity following large volcanic eruptions

Vitivinicultura brasileira: panorama setorial em 2010.

A vitivinicultura do Rio Grande do Sul (Serra Gaúcha, Região da Campanha, Serra do Sudeste e Região Central). A vitivinicultura de Santa Catarina. A vitivinicultura do Paraná. A vitivinicultura de São Paulo. A vitivinicultura de Minas Gerais. A vitivinicultura do Espírito Santo. A vitivinicultura de Goiás. A vitivinicultura do Mato Grosso. A vitivinicultura do Vale do Sub-Médio São Francisco.bitstream/item/58339/1/PROTAS-panoramavitivinicultura2010.pdfAcompanha um CD contendo o Diagnóstico qualitativo das principais regiões vitivinícolas brasileiras: aspectos tecnológicos e estruturais

A to Z of the Muon anomalous magnetic moment in the MSSM with Pati-Salam at the GUT scale

We analyse the low energy predictions of the minimal supersymmetric standard model (MSSM) arising from a GUT scale Pati-Salam gauge group further constrained by an A4 × Z5 family symmetry, resulting in four soft scalar masses at the GUT scale: one left-handed soft mass m0 and three right-handed soft masses m1, m2, m3, one for each generation. We demonstrate that this model, which was initially developed to describe the neutrino sector, can explain collider and non-collider measurements such as the dark matter relic density, the Higgs boson mass and, in particular, the anomalous magnetic moment of the muon (g − 2)μ. Since about two decades, (g − 2)μ suffers a puzzling about 3σ excessoftheexperimentallymeasuredvalueoverthetheoreticalprediction,whichour model is able to fully resolve. As the consequence of this resolution, our model predicts specific regions of the parameter space with the specific properties including light smuons and neutralinos, which could also potentially explain di-lepton excesses observed by CMS and ATLAS

THREE METHODS TO EVALUATE THE USE OF EVAPORATIVE COOLING FOR HUMAN THERMAL COMFORT

This paper presents three methods that can be used as reference for efficientuse of evaporative cooling systems, applying it, latter, to several Braziliancities, characterized by different climates. Initially it presents the basicprinciples of direct and indirect evaporative cooling and defines theeffectiveness of the systems. Afterwards, it presents three methods thatallows to determinate where the systems are more efficient. It concludesthat evaporative cooling systems have a very large potential to propitiatethermal comfort and can still be used as an alternative to conventionalsystems in regions where the design wet bulb temperature is under 24ºC

A MATHEMATICAL MODEL FOR DIRECT EVAPORATIVE COOLING AIR CONDITIONING SYSTEM

Air conditioning systems are responsible for increasing men's work efficiency as well for his comfort, mainly in the warm periods of the year. Currently, the most used system is the mechanical vapor compression system. However, in many cases, evaporative cooling system can be an economical alternative to replace the conventional system, under several conditions, or as a pre-cooler in the conventional systems. It leads to a reduction in the operational cost, comparing with systems using only mechanical refrigeration. Evaporative cooling operates using induced processes of heat and mass transfer, where water and air are the working fluids. It consists in water evaporation, induced by the passage of an air flow, thus decreasing the air temperature. This paper presents the basic principles of the evaporative cooling process for human thermal comfort, the principles of operation for the direct evaporative cooling system and the mathematical development of the equations of thermal exchanges, allowing the determination of the effectiveness of saturation. It also presents some results of experimental tests in a direct evaporative cooler that take place in the Air Conditioning Laboratory at the University of Taubaté Mechanical Engineering Department, and the experimental results are used to determinate the convective heat transfer coefficient and to compare with the mathematical model

Creation of Rydberg Polarons in a Bose Gas

We report spectroscopic observation of Rydberg polarons in an atomic Bose gas. Polarons are created by excitation of Rydberg atoms as impurities in a strontium Bose-Einstein condensate. They are distinguished from previously studied polarons by macroscopic occupation of bound molecular states that arise from scattering of the weakly bound Rydberg electron from ground-state atoms. The absence of a $p$-wave resonance in the low-energy electron-atom scattering in Sr introduces a universal behavior in the Rydberg spectral lineshape and in scaling of the spectral width (narrowing) with the Rydberg principal quantum number, $n$. Spectral features are described with a functional determinant approach (FDA) that solves an extended Fr\"{o}hlich Hamiltonian for a mobile impurity in a Bose gas. Excited states of polyatomic Rydberg molecules (trimers, tetrameters, and pentamers) are experimentally resolved and accurately reproduced with FDA.Comment: 5 pages, 3 figure