3,105 research outputs found

    The structure of human CD23 and its interactions with IgE and CD21

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    The low-affinity immunoglobulin E (IgE) receptor, CD23 (FcɛRII), binds both IgE and CD21 and, through these interactions, regulates the synthesis of IgE, the antibody isotype that mediates the allergic response. We have determined the three-dimensional structure of the C-type lectin domain of CD23 in solution by nuclear magnetic resonance spectroscopy. An analysis of concentration-dependent chemical shift perturbations have allowed us to identify the residues engaged in self-association to the trimeric state, whereas ligand-induced changes have defined the binding sites for IgE and CD21. The results further reveal that CD23 can bind both ligands simultaneously. Despite the C-type lectin domain structure, none of the interactions require calcium. We also find that IgE and CD23 can interact to form high molecular mass multimeric complexes. The interactions that we have described provide a solution to the paradox that CD23 is involved in both up- and down-regulation of IgE and provide a structural basis for the development of inhibitors of allergic disease

    Advancing understanding on industrial relations in multinational companies: key research challenges and the INTREPID contribution

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    peer-reviewedThis paper has three principal aims. It firstly provides some theoretical background on the key current research issues and challenges in regard to industrial relations in multinational companies. It then presents a concise review of scholarship to date on industrial relations in multinational companies using INTREPID (Investigation of Transnationals Employment Practices: an International Database) data. Finally, the paper identifies some of the main industrial relations issues that remain to be addressed, in effect charting a form of research agenda for future work using the INTREPID data, with particular focus on the potential contribution from ‘late joiners’ to the INTREPID project.ACCEPTEDpeer-reviewe

    Deterministic entanglement and tomography of ion spin qubits

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    We have implemented a universal quantum logic gate between qubits stored in the spin state of a pair of trapped calcium 40 ions. An initial product state was driven to a maximally entangled state deterministically, with 83% fidelity. We present a general approach to quantum state tomography which achieves good robustness to experimental noise and drift, and use it to measure the spin state of the ions. We find the entanglement of formation is 0.54.Comment: 3 figures, 4 pages, footnotes fixe

    Long-lived mesoscopic entanglement outside the Lamb-Dicke regime

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    We create entangled states of the spin and motion of a single 40^{40}Ca+^+ ion in a linear ion trap. The motional part consists of coherent states of large separation and long coherence time. The states are created by driving the motion using counterpropagating laser beams. We theoretically study and experimentally observe the behaviour outside the Lamb-Dicke regime, where the trajectory in phase space is modified and the coherent states become squeezed. We directly observe the modification of the return time of the trajectory, and infer the squeezing. The mesoscopic entanglement is observed up to Δα=5.1\Delta \alpha = 5.1 with coherence time 170 microseconds and mean phonon excitation \nbar = 16.Comment: 5 pages, 3 figures. Revised version after editor comment

    Survey of the Illinois Endangered Kankakee Mallow, Iliamna remote, in Kankakee County

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    Iliamna remota Greene (Malvaceae), endemic only to Langham Island in the Kankakee River, Kankakee County, Illinois, is a state endangered species. During the present study, the size of the population was determined, the habitat structure in and around the individual colonies analyzed, and management recommendation made to potentially increase the size of the population. During the summer of 2005, the I remota population consisted of 1,074 stems in 12 colonies, located along the northwest side of the island. In late June, flowering appeared to be prolific, where means and standard deviations of floral buds and open flowers were 1.6 :t 1.2 and 2.1 :t 1.7 per stem, respectively. By late July, however, flowering was sporadic, but many flowering stems had set seed with the mean number of fruits being 1.2 :t 0.9 per stem. Forty percent of sampled seeds germinated after being treated in hot water (80°C) for 10 seconds. Common species associated with I remota colonies were the cool-season Eurasian grass, Poa pratensis, and the East Asian shrub Lonicera maackii, along with 22 native species and a few other exotics. Previous management included cutting and burning of the shrubby vegetation in and around the l remota colonies. A return to these management practices is suggested

    Survey of the Illinois Endangered Kankakee Mallow, Iliamna remota, in Kankakee County

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    Iliamna remota Greene (Malvaceae), endemic only to Langham Island in the Kankakee River, Kankakee County, Illinois, is a state endangered species. During the present study, the size of the population was determined, the habitat structure in and around the individual colonies analyzed, and management recommendation made to potentially increase the size of the population. During the summer of 2005, the I remota population consisted of 1,074 stems in 12 colonies, located along the northwest side of the island. In late June, flowering appeared to be prolific, where means and standard deviations of floral buds and open flowers were 1.6 :t 1.2 and 2.1 :t 1.7 per stem, respectively. By late July, however, flowering was sporadic, but many flowering stems had set seed with the mean number of fruits being 1.2 :t 0.9 per stem. Forty percent of sampled seeds germinated after being treated in hot water (80°C) for 10 seconds. Common species associated with I remota colonies were the cool-season Eurasian grass, Poa pratensis, and the East Asian shrub Lonicera maackii, along with 22 native species and a few other exotics. Previous management included cutting and burning of the shrubby vegetation in and around the l remota colonies. A return to these management practices is suggested

    Issues Around Researching OHS of Samoan Migrant Workers

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    Workers from Pacific nations constitute a substantial proportion of the labour force in NZ, particularly in Auckland, which has one of the largest concentrations of Pacific Island workers in the world. Samoans constitute the largest Pacific ethnic group in NZ, comprising 131,103 or 49% of the resident Pacific population (265,974) (Statistics NZ, 2010). However, Pacific Island workers in NZ are typically employed in low paid, precarious, hazardous work that often has little chance of advancement. There is also some evidence that Pacific Island workers are over­represented in NZ’s work­related injury and illness statistics (Allen & Clarke, 2006). While occupational health and safety (OHS) of Pacific Island migrant workers highlights a number of issues, studies often provide inadequate explanations of what exactly is occurring or fully capture the working experiences of Pacific Island migrant workers. This paper reports on the initial work undertaken as part of an international collaborative study located in Samoa and NZ, aimed at investigating the OHS experiences of Samoan migrant workers. In particular, the paper presents a multi­layered framework and a set of research principles that can be used to illuminate often inaccessible populations located in changing working and living environments. Finally, this study exemplifies the complex issues surrounding the migrant workers’ health and safety, workers’ compensation and rehabilitation

    Search for correlation effects in linear chains of trapped ions

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    We report a precise search for correlation effects in linear chains of 2 and 3 trapped Ca+ ions. Unexplained correlations in photon emission times within a linear chain of trapped ions have been reported, which, if genuine, cast doubt on the potential of an ion trap to realize quantum information processing. We observe quantum jumps from the metastable 3d 2D_{5/2} level for several hours, searching for correlations between the decay times of the different ions. We find no evidence for correlations: the number of quantum jumps with separations of less than 10 ms is consistent with statistics to within errors of 0.05%; the lifetime of the metastable level derived from the data is consistent with that derived from independent single-ion data at the level of the experimental errors 1%; and no rank correlations between the decay times were found with sensitivity to rank correlation coefficients at the level of |R| = 0.024.Comment: With changes to introduction. 5 pages, including 4 figures. Submitted to Europhys. Let
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