86 research outputs found
Characterisation of a three-dimensional Brownian motor in optical lattices
We present here a detailed study of the behaviour of a three dimensional
Brownian motor based on cold atoms in a double optical lattice [P. Sjolund et
al., Phys. Rev. Lett. 96, 190602 (2006)]. This includes both experiments and
numerical simulations of a Brownian particle. The potentials used are spatially
and temporally symmetric, but combined spatiotemporal symmetry is broken by
phase shifts and asymmetric transfer rates between potentials. The diffusion of
atoms in the optical lattices is rectified and controlled both in direction and
speed along three dimensions. We explore a large range of experimental
parameters, where irradiances and detunings of the optical lattice lights are
varied within the dissipative regime. Induced drift velocities in the order of
one atomic recoil velocity have been achieved.Comment: 8 pages, 14 figure
Discovery of the Isotopes with 11 <= Z <= 19
A total of 194 isotopes with 11 Z 19 have been identified to
date. The discovery of these isotopes which includes the observation of unbound
nuclei, is discussed. For each isotope a brief summary of the first refereed
publication, including the production and identification method, is presented.Comment: to be pubslihed in At. Data Nucl. Data Table
DNA microarray revealed and RNAi plants confirmed key genes conferring low Cd accumulation in barley grains
List of genes down-regulated in both W6nk2 and Zhenong8 after 15Â days exposure to 5Â ÎźM Cd. (DOC 130 kb
Food webs: reconciling the structure and function of biodiversity
The global biodiversity crisis concerns not only unprecedented loss of species within communities, but also related consequences for ecosystem function. Community ecology focuses on patterns of species richness and community composition, whereas ecosystem ecology focuses on fluxes of energy and materials. Food webs provide a quantitative framework to combine these approaches and unify the study of biodiversity and ecosystem function. We summarise the progression of food-web ecology and the challenges in using the food-web approach. We identify five areas of research where these advances can continue, and be applied to global challenges. Finally, we describe what data are needed in the next generation of food-web studies to reconcile the structure and function of biodiversity.No Full Tex
Characterizing the role of rice NRAMP5 in Manganese, Iron and Cadmium Transport
Metals like manganese (Mn) and iron (Fe) are essential for metabolism, while cadmium (Cd) is toxic for virtually all living organisms. Understanding the transport of these metals is important for breeding better crops. We have identified that OsNRAMP5 contributes to Mn, Fe and Cd transport in rice. OsNRAMP5 expression was restricted to roots epidermis, exodermis, and outer layers of the cortex as well as in tissues around the xylem. OsNRAMP5 localized to the plasma membrane, and complemented the growth of yeast strains defective in Mn, Fe, and Cd transport. OsNRAMP5 RNAi (OsNRAMP5i) plants accumulated less Mn in the roots, and less Mn and Fe in shoots, and xylem sap. The suppression of OsNRAMP5 promoted Cd translocation to shoots, highlighting the importance of this gene for Cd phytoremediation. These data reveal that OsNRAMP5 contributes to Mn, Cd, and Fe transport in rice and is important for plant growth and development
The Magnetoelectric Effect in Transition Metal Oxides: Insights and the Rational Design of New Materials from First Principles
The search for materials displaying a large magnetoelectric effect has
occupied researchers for many decades. The rewards could include not only
advanced electronics technologies, but also fundamental insights concerning the
dielectric and magnetic properties of condensed matter. In this article, we
focus on the magnetoelectric effect in transition metal oxides and review the
manner in which first-principles calculations have helped guide the search for
(and increasingly, predicted) new materials and shed light on the microscopic
mechanisms responsible for magnetoelectric phenomena.Comment: 24 pages, 12 figure
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