159 research outputs found

    Island disaster para-diplomacy in the commonwealth

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    This chapter covers one particular aspect of the foreign relations of non-sovereign island jurisdictions (SNIJs), namely relations arising from disaster-related activities. Islands are among the territories most seriously affected by calamities, including the spectre of rising seas that may come with climate change. Yet non-sovereign islands are not so well equipped to speak and act effectively for themselves in the face of such threats. This may be true even within the governing structures in which these islands find themselves, but it is even more serious given the weaknesses that may exist in their capacity to speak to and act in the international community on disaster-related activities.peer-reviewe

    Contextually aware suggestions for online information resources

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    Novice users often find it challenging to realize the full potential of available information resources. One approach to help such users is to present them with a categorized directory of ranked recommendations for useful information resources, such as apps or websites. However, such a directory may not help discover new resources that can be particularly relevant at specific times based on the user’s current location. This disclosure describes techniques to provide a personalized catalog of suggestions for information resources relevant to a user’s current context, which is obtained with user permission. A personalized catalog of contextual suggestions can help novices broaden their awareness and understanding of available online resources and expose them to a range of tasks that can be accomplished online. In addition to standalone operation, the catalog functionality can be embedded in various commonly used systems and can serve as a mechanism for entities to provide relevant information to individuals in their vicinity

    Super-heavy fermion material as metallic refrigerant for adiabatic demagnetization cooling

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    Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, as the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3^3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas is being increasingly difficult due to the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. Here, we show that a new type of refrigerant, super-heavy electron metal, YbCo2_2Zn20_{20}, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. A number of advantages includes much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1x_{1-x}Scx_xCo2_2Zn20_{20} by partial Sc substitution with xx\sim0.19. The substitution induces chemical pressure which drives the materials close to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures enabling final temperatures well below 100 mK. Such performance has up to now been restricted to insulators. Since nearly a century the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for the cryogen-free refrigeration

    A structural model for K2P potassium channels based on 23 pairs of interacting sites and continuum electrostatics

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    K2PØ, the two-pore domain potassium background channel that determines cardiac rhythm in Drosophila melanogaster, and its homologues that establish excitable membrane activity in mammals are of unknown structure. K2P subunits have two pore domains flanked by transmembrane (TM) spans: TM1-P1-TM2-TM3-P2-TM4. To establish spatial relationships in K2PØ, we identified pairs of sites that display electrostatic compensation. Channels silenced by the addition of a charge in pore loop 1 (P1) or P2 were restored to function by countercharges at specific second sites. A three-dimensional homology model was determined using the crystal structure of KV1.2, effects of K2PØ mutations to establish alignment, and compensatory charge–charge pairs. The model was refined and validated by continuum electrostatic free energy calculations and covalent linkage of introduced cysteines. K2P channels use two subunits arranged so that the P1 and P2 loops contribute to one pore, identical P loops face each other diagonally across the pore, and the channel complex has bilateral symmetry with a fourfold symmetric selectivity filter

    Mammalian Stem Cells Reprogramming in Response to Terahertz Radiation

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    We report that extended exposure to broad-spectrum terahertz radiation results in specific changes in cellular functions that are closely related to DNA-directed gene transcription. Our gene chip survey of gene expression shows that whereas 89% of the protein coding genes in mouse stem cells do not respond to the applied terahertz radiation, certain genes are activated, while other are repressed. RT-PCR experiments with selected gene probes corresponding to transcripts in the three groups of genes detail the gene specific effect. The response was not only gene specific but also irradiation conditions dependent. Our findings suggest that the applied terahertz irradiation accelerates cell differentiation toward adipose phenotype by activating the transcription factor peroxisome proliferator-activated receptor gamma (PPARG). Finally, our molecular dynamics computer simulations indicate that the local breathing dynamics of the PPARG promoter DNA coincides with the gene specific response to the THz radiation. We propose that THz radiation is a potential tool for cellular reprogramming

    Role of the Blood-Brain Barrier in the Formation of Brain Metastases

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    The majority of brain metastases originate from lung cancer, breast cancer and malignant melanoma. In order to reach the brain, parenchyma metastatic cells have to transmigrate through the endothelial cell layer of brain capillaries, which forms the morphological basis of the blood-brain barrier (BBB). The BBB has a dual role in brain metastasis formation: it forms a tight barrier protecting the central nervous system from entering cancer cells, but it is also actively involved in protecting metastatic cells during extravasation and proliferation in the brain. The mechanisms of interaction of cancer cells and cerebral endothelial cells are largely uncharacterized. Here, we provide a comprehensive review on our current knowledge about the role of junctional and adhesion molecules, soluble factors, proteolytic enzymes and signaling pathways mediating the attachment of tumor cells to brain endothelial cells and the transendothelial migration of metastatic cells. Since brain metastases represent a great therapeutic challenge, it is indispensable to understand the mechanisms of the interaction of tumor cells with the BBB in order to find targets of prevention of brain metastasis formation
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