907 research outputs found

    Trust in the US-EU fruit and vegetable chain: Do US exporters understand EU importers?

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    Research on organizational and inter organizational trust has become an important field in management and marketing literature, as it is perceived as a pivotal aspect of business transactions. However, clarifications are still needed on the issue of whom we trust; is the person whom we are trading with trusted, or the organization, or just the product‐quality? Not only has this question not been answered within this field of research, neither have cultural differences have been described to any great extent. Additionally, if the perceived factors important to establish trusting relationships may or may not be the same on the buyers and the sellers side in international business transaction in food chains. The primary objective of this research study therefore is to identify how well US exporters understand the elements of trust that establish strong relationships with EU importers. The Analytical Hierarchy Process was used to evaluate the importance of different trust elements in interviews conducted with US exporters and EU importers of fruits and vegetables. Results are compared, providing both a picture of the important facets of trust, as well as whether the partners understand the perspectives of the other partner

    A counter-rotating Couette apparatus to study deformation of a sub-millimeter sized particle in shear flow

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    We describe a new counter-rotating Couette apparatus that has been developed for deformation studies of single sub-millimeter sized particles in shear flow. New features are the adaption to the low viscosities of water-based systems and temperature control of the device. The inner to outer radius ratio of the cylinders used is 0.9785 and the height to width aspect ratio of the gap is 4.0, while the inner radius is 100 mm. Because of the limited particle size a high mechanical accuracy of the Couette geometry is necessary. The swing of the inner cylinder is less than 2 μm and that of the outer cylinder less than 4 μm. We achieved this by carefully choosing the design parameters of the aerostatic bearing and the coupling between cylinder and motor unit. Furthermore, special drive units give a shear rate resolution of 0.018 s−1, while the maximum shear rate is 100 s−1. For a liquid viscosity on the order of 1 mPas the effective maximum shear rate is 30 s−1. We have shown that deformations as small as (L−B)/(L+B) ≈ 0.01 of giant bilayer vesicles (typical radius 10 μm) with length L and width B can be observed with our device

    Reconfigurable Photonic Crystal Cavities

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    Photonic crystals are optical structures that contain a periodic modulation of their refractive index, allowing them to control light in recent years of an unprecedented capacity. Photonic crystals may take on a variety of configurations, in particular the photonic crystal cavity, which may “hold” light in small volumes comparable to the light’s wavelength. This capability to spatially confine light opens up countless possibilities to explore for research in telecommunications, quantum electrodynamics experiments and high-resolution sensor applications. However, the vast functionality potentially made available by photonic crystal cavities is limited due to the difficulty in redefining photonic crystal components once they are formed in their (typically) solid material. The work presented in this thesis investigates several approaches to overcome this issue by reconfiguring photonic crystal cavities

    Local genomic adaptation of coral reef-associated microbiomes to gradients of natural variability and anthropogenic stressors

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    Holobionts are species-specific associations between macro- and microorganisms. On coral reefs, the benthic coverage of coral and algal holobionts varies due to natural and anthropogenic forcings. Different benthic macroorganisms are predicted to have specific microbiomes. In contrast, local environmental factors are predicted to select for specific metabolic pathways in microbes. To reconcile these two predictions, we hypothesized that adaptation of microbiomes to local conditions is facilitated by the horizontal transfer of genes responsible for specific metabolic capabilities. To test this hypothesis, microbial metagenomes were sequenced from 22 coral reefs at 11 Line Islands in the central Pacific that together span a wide range of biogeochemical and anthropogenic influences. Consistent with our hypothesis, the percent cover of major benthic functional groups significantly correlated with particular microbial taxa. Reefs with higher coral cover had a coral microbiome with higher abundances of Alphaproteobacteria (such as Rhodobacterales and Sphingomonadales), whereas microbiomes of algae-dominated reefs had higher abundances of Gammaproteobacteria (such as Alteromonadales, Pseudomonadales, and Vibrionales), Betaproteobacteria, and Bacteriodetes. In contrast to taxa, geography was the strongest predictor of microbial community metabolism. Microbial communities on reefs with higher nutrient availability (e.g., equatorial upwelling zones) were enriched in genes involved in nutrient-related metabolisms (e.g., nitrate and nitrite ammonification, Ton/Tol transport, etc.). On reefs further from the equator, microbes had more genes encoding chlorophyll biosynthesis and photosystems I/II. These results support the hypothesis that core microbiomes are determined by holobiont macroorganisms, and that those core taxa adapt to local conditions by selecting for advantageous metabolic genes

    Harnessing gene expression profiles for the identification of ex vivo drug response genes in pediatric acute myeloid leukemia

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    Novel treatment strategies are of paramount importance to improve clinical outcomes in pediatric AML. Since chemotherapy is likely to remain the cornerstone of curative treatment of AML, insights in the molecular mechanisms that determine its cytotoxic effects could aid further treatment optimization. To assess which genes and pathways are implicated in tumor drug resistance, we correlated ex vivo drug response data to genome-wide gene expression profiles of 73 primary pediatric AML samples obtained at initial diagnosis. Ex vivo response of primary AML blasts towards cytarabine (Ara C), daunorubicin (DNR), etoposide (VP16), and cladribine (2-CdA) was associated with the expression of 101, 345, 206, and 599 genes, respectively (p < 0.001, FDR 0.004–0.416). Microarray based expression of multiple genes was technically validated using qRT-PCR for a selection of genes. Moreover, expression levels of BRE, HIF1A, and CLEC7A were confirmed to be significantly (p < 0.05) associated with ex vivo drug response in an independent set of 48 primary pediatric AML patients. We present unique data that addresses transcriptomic analyses of the mechanisms underlying ex vivo drug response of primary tumor samples. Our data suggest that distinct gene expression profiles are associated with ex vivo drug response, and may confer a priori drug resistance in leukemic cells. The described associations represent a fundament for the development of interventions to overcome drug resistance in AML, and maximize the benefits of current chemotherapy for sensitive patients

    Rare non-Wilms' tumors in children

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    We report our institutional experience of the management of 2 cases of rare non-Wilms' tumors; a rhabdoid tumor in a 17-month old boy and a clear cell sarcoma in a 5-year old girl. The two patients were treated with ifosfamide/carboplatin/etoposide (ICE) alternating with vincristine/doxorubicin/cyclophosphamide (VDC) and cyclophosphamide/etoposide (CE) alternating with vincristine/doxorubicin/cyclophosphamide (VDC) and radiotherapy, respectively. Both patients showed full response with no significant adverse events. At 2-year follow up, they are disease and relapse free. Although contemporary treatment regimens are very promising, multicenter collaborative studies are needed in order to define a standard treatment for non-Wilms' tumors

    Stochastic Production Of Kink-Antikink Pairs In The Presence Of An Oscillating Background

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    We numerically investigate the production of kink-antikink pairs in a (1+1)(1+1) dimensional ϕ4\phi^4 field theory subject to white noise and periodic driving. The twin effects of noise and periodic driving acting in conjunction lead to considerable enhancement in the kink density compared to the thermal equilibrium value, for low dissipation coefficients and for a specific range of frequencies of the oscillating background. The dependence of the kink-density on the temperature of the heat bath, the amplitude of the oscillating background and value of the dissipation coefficient is also investigated. An interesting feature of our result is that kink-antikink production occurs even though the system always remains in the broken symmetry phase.Comment: Revtex, 21 pages including 7 figures; more references adde

    Early Atomic Models - From Mechanical to Quantum (1904-1913)

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    A complete history of early atomic models would fill volumes, but a reasonably coherent tale of the path from mechanical atoms to the quantum can be told by focusing on the relevant work of three great contributors to atomic physics, in the critically important years between 1904 and 1913: J. J. Thomson, Ernest Rutherford and Niels Bohr. We first examine the origins of Thomson's mechanical atomic models, from his ethereal vortex atoms in the early 1880's, to the myriad "corpuscular" atoms he proposed following the discovery of the electron in 1897. Beyond predictions for the periodicity of the elements, the application of Thomson's atoms to problems in scattering and absorption led to quantitative predictions that were confirmed by experiments with high-velocity electrons traversing thin sheets of metal. Still, the much more massive and energetic {\alpha}-particles being studied by Rutherford were better suited for exploring the interior of the atom, and careful measurements on the angular dependence of their scattering eventually allowed him to infer the existence of an atomic nucleus. Niels Bohr was particularly troubled by the radiative instability inherent to any mechanical atom, and succeeded in 1913 where others had failed in the prediction of emission spectra, by making two bold hypotheses that were in contradiction to the laws of classical physics, but necessary in order to account for experimental facts.Comment: 58 Pages + References, 8 Figures. Accepted for publication in the European Physical Journal H (Historical Perspectives on Contemporary Physics). V2 - minor typos corrected and a footnote added to p.2
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