52 research outputs found

    Photoionization of ultracold and Bose-Einstein condensed Rb atoms

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    Photoionization of a cold atomic sample offers intriguing possibilities to observe collective effects at extremely low temperatures. Irradiation of a rubidium condensate and of cold rubidium atoms within a magneto-optical trap with laser pulses ionizing through 1-photon and 2-photon absorption processes has been performed. Losses and modifications in the density profile of the remaining trapped cold cloud or the remaining condensate sample have been examined as function of the ionizing laser parameters. Ionization cross-sections were measured for atoms in a MOT, while in magnetic traps losses larger than those expected for ionization process were measured.Comment: 9 pages, 7 figure

    Transcriptional and genomic parallels between the monoxenous parasite Herpetomonas muscarum and Leishmania

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    Trypanosomatid parasites are causative agents of important human and animal diseases such as sleeping sickness and leishmaniasis. Most trypanosomatids are transmitted to their mammalian hosts by insects, often belonging to Diptera (or true flies). These are called dixenous trypanosomatids since they infect two different hosts, in contrast to those that infect just insects (monoxenous). However, it is still unclear whether dixenous and monoxenous trypanosomatids interact similarly with their insect host, as fly-monoxenous trypanosomatid interaction systems are rarely reported and under-studied–despite being common in nature. Here we present the genome of monoxenous trypanosomatid Herpetomonas muscarum and discuss its transcriptome during in vitro culture and during infection of its natural insect host Drosophila melanogaster. The H. muscarum genome is broadly syntenic with that of human parasite Leishmania major. We also found strong similarities between the H. muscarum transcriptome during fruit fly infection, and those of Leishmania during sand fly infections. Overall this suggests Drosophila-Herpetomonas is a suitable model for less accessible insect-trypanosomatid host-parasite systems such as sand fly-Leishmania

    Host–pathogen interactions in bacterial meningitis

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    Cross-section for collisions of ultracold

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    In a magneto-optical trap (MOT) we are able to simultaneously trap and cool 7Li and Na. We investigated the loading behavior of the cloud of Li atoms in presence of the overlapped cloud of cold Na atoms, and, by blocking the weak repumping beam for Na, compared it with the loading curve for Li atoms only. Out of these loading curves we calculated the collision cross-section of Na on Li to be 10-11 cm3/s

    Cross-section for collisions of ultracold 7 \mathsf {^7} Li with Na

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    Data from: A synthesis of diets and trophic overlap of marine species in the California current

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    A key step toward ecosystem-based management is to better understand how interactions within food webs affect species of commercial and conservation importance. Here we provide comprehensive diet information and food web analysis for major taxa within the California Current ecosystem, including fish, marine mammals, birds, and invertebrates. We synthesized 75 published diet studies from this ecosystem and calculated representative diets for each species or aggregated functional group. We assessed diet relatedness using hierarchical cluster analysis and calculated diet overlaps based on percent similarity index (PSI). Both analyses were performed on functional group data and also separately for each vertebrate species. Cluster analysis identified distinct feeding guilds and revealed both intuitive and novel diet similarities between several species and functional groups. One intuitive example is that functional groups preying on euphausiids, a key forage species in the California Current, show a high amount of overlap. A novel example is the significant diet overlap of shallow small rockfish and baleen whales (e.g., grey whales [Eschrichtius robustus]), both of which consume large amounts of benthic invertebrates. Functional groups were highly significant in explaining the PSI differences between species, which suggests that key ecological interactions will be preserved in ecosystem models that use these functional groups. A visual representation of the complete food web and calculation of food web statistics suggest that there are strong similarities between the food webs of the California Current and the Benguela Current, a similar upwelling-driven eastern boundary current off the southwest coast of Africa

    DietsOfPredatorsThatAreJuveniles

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    Diets of California Current marine animals (West Coast of US, parts of Canada and Mexico) for predators that are juveniles
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