Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in "artificial" magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed.Comment: Review article. v2: published version, 135 pages, 34 figure

Mechanical Work as an Indirect Measure of Subjective Costs Influencing Human Movement

To descend a flight of stairs, would you rather walk or fall? Falling seems to have some obvious disadvantages such as the risk of pain or injury. But the preferred strategy of walking also entails a cost for the use of active muscles to perform negative work. The amount and distribution of work a person chooses to perform may, therefore, reflect a subjective valuation of the trade-offs between active muscle effort and other costs, such as pain. Here we use a simple jump landing experiment to quantify the work humans prefer to perform to dissipate the energy of landing. We found that healthy normal subjects (N = 8) preferred a strategy that involved performing 37% more negative work than minimally necessary (P<0.001) across a range of landing heights. This then required additional positive work to return to standing rest posture, highlighting the cost of this preference. Subjects were also able to modulate the amount of landing work, and its distribution between active and passive tissues. When instructed to land softly, they performed 76% more work than necessary (P<0.001), with a higher proportion from active muscles (89% vs. 84%, P<0.001). Stiff-legged landings, performed by one subject for demonstration, exhibited close to the minimum of work, with more of it performed passively through soft tissue deformations (at least 30% in stiff landings vs. 16% preferred). During jump landings, humans appear not to minimize muscle work, but instead choose to perform a consistent amount of extra work, presumably to avoid other subjective costs. The degree to which work is not minimized may indirectly quantify the relative valuation of costs that are otherwise difficult to measure

Colony-level differences in the scaling rules governing wood ant compound eye structure

Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers' eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population

Meaning of leprosy for people who have experienced treatment during the sulfonic and multidrug therapy periods

Objetivo:analizar los significados de la lepra para las personas que fueron tratadas en el período sulfónico y en el período de poliquimioterapia.Método:estudio de naturaleza cualitativa fundamentado en el abordaje histórico cultural de Vygotsky, el cual orientó la construcción y análisis de los datos. Fueron incluidos ocho entrevistados que ya tuvieron lepra y que realizaron tratamiento en el período sulfónico y de poliquimioterapia, siendo participantes del Movimiento de Reintegración de Personas Afectadas por la Lepra.Resultados:los significados fueron organizados en tres núcleos de significación: manchas en el cuerpo: alguna cosa está fuera de orden; ¿Lepra o enfermedad de Hansen?; y lepra a partir de la inserción en el Movimiento de Reintegración de Personas Afectadas por la Lepra. Conclusión: los significados de la lepra para las personas tratadas en los dos períodos apuntan para la construcción compleja de los mismos, indicando diferencias y semejanzas en los dos períodos. Los profesionales de la salud pueden contribuir para el cambio de significados, ya que estos son socialmente construidos y las transformaciones son continuas.Objetivo:analisar significados da hanseníase para as pessoas que foram tratadas no período sulfônico e no período da poliquimioterapia.Método:estudo de natureza qualitativa fundamentado na abordagem histórico-cultural de Vigotski, a qual orientou a construção e análise dos dados. Foram incluídos oito entrevistados que já tiveram hanseníase e que realizaram tratamento no período sulfônico e da poliquimioterapia, sendo participantes do Movimento de Reintegração das Pessoas Atingidas pela Hanseníase.Resultados:os significados foram organizados em três núcleos de significação: manchas no corpo: alguma coisa está fora de ordem; lepra ou hanseníase? e hanseníase a partir da inserção no Movimento de Reintegração das Pessoas Atingidas pela Hanseníase.Conclusão:os significados de hanseníase para pessoas tratadas nos dois períodos apontam para a construção complexa dos mesmos, indicando diferenças e semelhanças nos dois períodos. Os profissionais de saúde podem contribuir para a mudança de significados, pois esses são socialmente construídos e as transformações são contínuas.Objective: to analyze the meanings of leprosy for people treated during the sulfonic and multidrug therapy periods.Method: qualitative nature study based on the Vigotski's historical-cultural approach, which guided the production and analysis of data. It included eight respondents who have had leprosy and were submitted to sulfonic and multidrug therapy treatments. The participants are also members of the Movement for Reintegration of People Affected by Leprosy.Results: the meanings were organized into three meaning cores: spots on the body: something is out of order; leprosy or hanseniasis? and leprosy from the inclusion in the Movement for Reintegration of People Affected by Leprosy.Conclusion: the meanings of leprosy for people submitted to both regimens point to a complex construction thereof, indicating differences and similarities in both treatments. Health professionals may contribute to the change of the meanings, since these are socially constructed and the changes are continuous

Holocene changes in the position and intensity of the southern Westerly wind belt

The position and intensity of the southern westerly wind belt varies seasonally as a consequence of changes in sea surface temperature. During the austral winter, the belt expands northward and the wind intensity in the core decreases. Conversely, during the summer, the belt contracts, and the intensity within the core is strengthened. Reconstructions of the westerly winds since the last glacial maximum, however, have suggested that changes at a single site reflected shifts throughout the entire southern wind belt(1-4). Here we use sedimentological and pollen records to reconstruct precipitation patterns over the past 12,500 yr from sites along the windward side of the Andes. Precipitation at the sites, located in the present core and northern margin of the westerlies, is driven almost entirely by the wind belt(5), and can be used to reconstruct its intensity. Rather than varying coherently throughout the Holocene epoch, we find a distinct anti-phasing of wind strength between the core and northern margin over multi-millennial timescales. During the early Holocene, the core westerlies were strong whereas the northern margin westerlies were weak. We observe the opposite pattern in the late Holocene. As this variation resembles modern seasonal variability, we suggest that our observed changes in westerly wind strength can best be explained by variations in sea surface temperature in the eastern South Pacific Ocean