Thermalization via Heat Radiation of an Individual Object Thinner than the Thermal Wavelength

Modeling and investigating the thermalization of microscopic objects with arbitrary shape from first principles is of fundamental interest and may lead to technical applications. Here, we study, over a large temperature range, the thermalization dynamics due to far-field heat radiation of an individual, deterministically produced silica fiber with a predetermined shape and a diameter smaller than the thermal wavelength. The temperature change of the subwavelength-diameter fiber is determined through a measurement of its optical path length in conjunction with an ab initio thermodynamic model of the fiber structure. Our results show excellent agreement with a theoretical model that considers heat radiation as a volumetric effect and takes the emitter shape and size relative to the emission wavelength into account

Optical interface created by laser-cooled atoms trapped in the evanescent field surrounding an optical nanofiber

Trapping and optically interfacing laser-cooled neutral atoms is an essential requirement for their use in advanced quantum technologies. Here we simultaneously realize both of these tasks with cesium atoms interacting with a multi-color evanescent field surrounding an optical nanofiber. The atoms are localized in a one-dimensional optical lattice about 200 nm above the nanofiber surface and can be efficiently interrogated with a resonant light field sent through the nanofiber. Our technique opens the route towards the direct integration of laser-cooled atomic ensembles within fiber networks, an important prerequisite for large scale quantum communication schemes. Moreover, it is ideally suited to the realization of hybrid quantum systems that combine atoms with, e.g., solid state quantum devices

TRADUÇÃO DO CONTO AQUELE RELÓGIO ”“: DO LIVRO: A PISCINA DE AÇO FERVENTE E OUTROS CONTOS ”“ OBRA DE: ARTUR O. LOPES

O conto Aquele Relógio faz parte do livro A piscina de aço fervente e outros contos, de Artur O. Lopes, foi publicado no Rio de Janeiro em 2015 pela Ar Editora. Em 2010, ainda inédito, ficou entre os cinco finalistas do Prêmio Açorianos de Criação. Sua publicação anterior A casa da minha Vó e outros contos exóticos (2006), pela Edições Inteligentes, ficou em segundo lugar na categoria Contos e Crônicas do prêmio Jabuti em 2007

A sequence of abrupt climatic fluctuations in the north-eastern Caribbean related to the 8.2 ka event

A speleothem collected from Palco Cave (Puerto Rico) spans the 8.2 ka event, a time interval associated with fluctuations of Atlantic Ocean circulation and possible drying in the Caribbean region. While stalagmite delta 18O, delta 13C, and Mg/Ca data do not show a sustained change in mean state over the 8.2 ka event, the proxies provide robust evidence for three abrupt fluctuations toward drier conditions in rapid succession, each lasting less than two decades, occurring at 8.20, 8.14, and 8.02 ka BP. A cave monitoring program at Palco Cave supports the interpretation of the speleothem proxy records. Because changes in the position of the Intertropical Convergence Zone (ITCZ) are directly coupled to sea-surface temperature variations in the North Atlantic, we hypothesize that cold events in the North Atlantic temporarily limited the northward migration of the ITCZ and tropical rain belt in boreal summer during these abrupt drying periods. The speleothem record suggests that the 8.2 ka event was associated with rapid rainfall fluctuations in the northern Caribbean followed by a comparably warm and wet phase after the 8.2 ka event. This enhanced variability during the transitional period of the deglaciation appears to be linked to a fast coupling between interacting oceanic and atmospheric processes. This involves, in particular, the Atlantic Meridional Overturning Circulation in modulating interhemispheric heat transport

SUR LA LECTURE DE PROUST: LEITURAS E TRADUÇÕES

Em Sur la lecture, prefácio escrito para a tradução de Sesame and lilies, de John Ruskin, Marcel Proust expõe sua visão sobre a função crítica e filosófica da leitura, as quais podem ser aplicadas aos Estudos da Tradução, uma vez que todo ato tradutório parte de uma leitura aprofundada do texto-fonte. Ao mesmo tempo, nas considerações de Borges (1985) a leitura se constitui como uma estratégia crítica baseada na supressão da ideia de hierarquia do original sobre a tradução, validando todas as versões de uma mesma obra. No mesmo sentido, Berman (1995) enfatiza a leitura como uma das etapas constituintes da análise de traduções. É a partir desse olhar que apresentamos neste trabalho uma análise comparativa entre o texto-fonte e as traduções brasileira e argentina.  Através da apresentação e comentários de diferentes fragmentos, discutimos as soluções tradutórias encontradas por Carlos Vogt (1989) e Pedro Ubertone (2003).

EXEHDA-FDC: um framework colaborativo para o desenvolvimento de aplicações direcionado a UbiComp.

ERAD

uMED: Sensibilidade ao contexto na medicina ubíqua.

ERAD

A Nanofiber-Based Optical Conveyor Belt for Cold Atoms

We demonstrate optical transport of cold cesium atoms over millimeter-scale distances along an optical nanofiber. The atoms are trapped in a one-dimensional optical lattice formed by a two-color evanescent field surrounding the nanofiber, far red- and blue-detuned with respect to the atomic transition. The blue-detuned field is a propagating nanofiber-guided mode while the red-detuned field is a standing-wave mode which leads to the periodic axial confinement of the atoms. Here, this standing wave is used for transporting the atoms along the nanofiber by mutually detuning the two counter-propagating fields which form the standing wave. The performance and limitations of the nanofiber-based transport are evaluated and possible applications are discussed

New evidence for an early settlement of the Yucatán Peninsula, Mexico: The Chan Hol 3 woman and her meaning for the Peopling of the Americas.

Human presence on the Yucatán Peninsula reaches back to the Late Pleistocene. Osteological evidence comes from submerged caves and sinkholes (cenotes) near Tulum in the Mexican state of Quintana Roo. Here we report on a new skeleton discovered by us in the Chan Hol underwater cave, dating to a minimum age of 9.9±0.1 ky BP based on 230Th/U-dating of flowstone overlying and encrusting human phalanges. This is the third Paleoindian human skeleton with mesocephalic cranial characteristics documented by us in the cave, of which a male individual named Chan Hol 2 described recently is one of the oldest human skeletons found on the American continent. The new discovery emphasizes the importance of the Chan Hol cave and other systems in the Tulum area for understanding the early peopling of the Americas. The new individual, here named Chan Hol 3, is a woman of about 30 years of age with three cranial traumas. There is also evidence for a possible trepanomal bacterial disease that caused severe alteration of the posterior parietal and occipital bones of the cranium. This is the first time that the presence of such disease is reported in a Paleoindian skeleton in the Americas. All ten early skeletons found so far in the submerged caves from the Yucatán Peninsula have mesocephalic cranial morphology, different to the dolicocephalic morphology for Paleoindians from Central Mexico with equivalent dates. This supports the presence of two morphologically different Paleoindian populations for Mexico, coexisting in different geographical areas during the Late Pleistocene-Early Holocene

Nonlinear transmission through a tapered fiber in rubidium vapor

Sub-wavelength diameter tapered optical fibers surrounded by rubidium vapor can undergo a substantial decrease in transmission at high atomic densities due to the accumulation of rubidium atoms on the surface of the fiber. Here we demonstrate the ability to control these changes in transmission using light guided within the taper. We observe transmission through a tapered fiber that is a nonlinear function of the incident power. This effect can also allow a strong control beam to change the transmission of a weak probe beam.Comment: 10 pages, 4 figure