18 research outputs found

    Structuring Exotic Options Contracts on Water to Improve the Efficiency of Resource Allocation in the Water Spot Market

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    With the current drought in South-Eastern Australia highlighting the scarcity and value of inland Australia’s water resources, focus turns to how these resources can be allocated more efficiently. The first major step was taken almost a decade ago with the separation of land and water property rights allowing openly traded water markets. This study assesses the potential economic benefits that options contracts bring to the water market in the Murray Valley water market. Exotic call options are estimated using both Black-Scholes and skewness-and-kurtosis-amended Black-Scholes financial option pricing methods that are based on three years of data on water prices. While the presence of options would result in significant economic benefits in the more efficient trade of water on the open market for lower-value crops, there were mixed results from the attempt to price such options.options, skewness-and-kurtosis-amended Black-Scholes model, water, Environmental Economics and Policy, Financial Economics, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,

    SARS-CoV-2-specific T cell memory with common TCRαβ motifs is established in unvaccinated children who seroconvert after infection

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    As establishment of SARS-CoV-2-specific T cell memory in children remains largely unexplored, we recruited convalescent COVID-19 children and adults to define their circulating memory SARS-CoV-2-specific CD4+ and CD8+ T cells prior to vaccination. We analysed epitope-specific T cells directly ex vivo using seven HLA class-I and class-II tetramers presenting SARS-CoV-2 epitopes, together with Spike-specific B cells. Unvaccinated children who seroconverted had comparable spike-specific, but lower ORF1a- and N-specific memory T cell responses compared to adults. This agreed with our TCR sequencing data showing reduced clonal expansion in children. A strong stem cell memory phenotype and common T cell receptor motifs were detected within tetramer-specific T cells in seroconverted children. Conversely, children who did not seroconvert had tetramer-specific T cells of predominantly naïve phenotypes and diverse TCRαβ repertoires. Our study demonstrates generation of SARS-CoV-2-specific T cell memory with common TCRαβ motifs in unvaccinated seroconverted children after their first virus encounter

    Robust SARS-CoV-2 T cell responses with common TCR?? motifs toward COVID-19 vaccines in patients with hematological malignancy impacting B cells

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    Immunocompromised hematology patients are vulnerable to severe COVID-19 and respond poorly to vaccination. Relative deficits in immunity are, however, unclear, especially after 3 vaccine doses. We evaluated immune responses in hematology patients across three COVID-19 vaccination doses. Seropositivity was low after a first dose of BNT162b2 and ChAdOx1 (∼26%), increased to 59%–75% after a second dose, and increased to 85% after a third dose. While prototypical antibody-secreting cells (ASCs) and T follicular helper (Tfh) cell responses were elicited in healthy participants, hematology patients showed prolonged ASCs and skewed Tfh2/17 responses. Importantly, vaccine-induced expansions of spike-specific and peptide-HLA tetramer-specific CD4+/CD8+ T cells, together with their T cell receptor (TCR) repertoires, were robust in hematology patients, irrespective of B cell numbers, and comparable to healthy participants. Vaccinated patients with breakthrough infections developed higher antibody responses, while T cell responses were comparable to healthy groups. COVID-19 vaccination induces robust T cell immunity in hematology patients of varying diseases and treatments irrespective of B cell numbers and antibody response

    Structuring Exotic Options Contracts on Water to Improve the Efficiency of Resource Allocation in the Water Spot Market

    No full text
    With the current drought in South-Eastern Australia highlighting the scarcity and value of inland Australia's water resources, focus turns to how these resources can be allocated more efficiently. The first major step was taken almost a decade ago with the separation of land and water property rights allowing openly traded water markets. This study assesses the potential economic benefits that options contracts bring to the water market in the Murray Valley water market. Exotic call options are estimated using both Black-Scholes and skewness-and-kurtosis-amended Black-Scholes financial option pricing methods that are based on three years of data on water prices. While the presence of options would result in significant economic benefits in the more efficient trade of water on the open market for lower-value crops, there were mixed results from the attempt to price such options

    Structuring Exotic Options Contracts on Water to Improve the Efficiency of Resource Allocation in the Australian Water Market

    No full text
    The potential economic benefits that options contracts bring to the Murray Valley water market in Australia are assessed. Exotic call option prices are estimated using Black-Scholes and skewness-and-kurtosis-amended Black-Scholes option closed-form pricing methods that are based on mean weekly water prices between 2004 and 2008. While options would result in significant economic benefits through more efficient trade of water on the open market for lower-value crops, there were mixed results from attempts to price them. Results show that use of the standard Black-Scholes formula is likely to undervalue option prices considerably at all but improbably low levels of volatility in water prices. Water option prices are high relative to the net present value of option benefits for recent levels of volatility, which is likely to discourage the development of a water options market. Alternatives to reduce the option prices are discussed. Other potential constraints to the implementation of a water options trading system are outlined

    Structuring Exotic Options Contracts on Water to Improve the Efficiency of Resource Allocation in the Australian Water Market

    No full text
    The potential economic benefits that options contracts bring to the Murray Valley water market in Australia are assessed. Exotic call option prices are estimated using Black-Scholes and skewness-and-kurtosis-amended Black-Scholes option closed-form pricing methods that are based on mean weekly water prices between 2004 and 2008. While options would result in significant economic benefits through more efficient trade of water on the open market for lower-value crops, there were mixed results from attempts to price them. Results show that use of the standard Black-Scholes formula is likely to undervalue option prices considerably at all but improbably low levels of volatility in water prices. Water option prices are high relative to the net present value of option benefits for recent levels of volatility, which is likely to discourage the development of a water options market. Alternatives to reduce the option prices are discussed. Other potential constraints to the implementation of a water options trading system are outlined

    Structuring Exotic Options Contracts on Water to Improve the Efficiency of Resource Allocation in the Water Spot Market

    No full text
    With the current drought in South-Eastern Australia highlighting the scarcity and value of inland Australia’s water resources, focus turns to how these resources can be allocated more efficiently. The first major step was taken almost a decade ago with the separation of land and water property rights allowing openly traded water markets. This study assesses the potential economic benefits that options contracts bring to the water market in the Murray Valley water market. Exotic call options are estimated using both Black-Scholes and skewness-and-kurtosis-amended Black-Scholes financial option pricing methods that are based on three years of data on water prices. While the presence of options would result in significant economic benefits in the more efficient trade of water on the open market for lower-value crops, there were mixed results from the attempt to price such options

    The evolution of Photosystem II: insights into the past and future

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    This article attempts to address the molecular origin of Photosystem II (PSII), the central component in oxygenic photosynthesis. It discusses the possible evolution of the relevant cofactors needed for splitting water into molecular O2 with respect to the following functional domains in PSII: the reaction center (RC), the oxygen evolving complex (OEC), and the manganese stabilizing protein (MSP). Possible ancestral sources of the relevant cofactors are considered, as are scenarios of how these components may have been brought together to produce the intermediate steps in the evolution of PSII. Most importantly, the driving forces that maintained these intermediates for continued adaptation are considered. We then apply our understanding of the evolution of PSII to the bioengineering of a water oxidizing catalyst for utilization of solar energy

    Hematopoietic lineage cell-specific protein 1 functions in concert with the Wiskott-Aldrich syndrome protein to promote podosome array organization and chemotaxis in dendritic cells

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    Dendritic cells (DCs) are professional APCs that reside in peripheral tissues and survey the body for pathogens. Upon activation by inflammatory signals, DCs undergo a maturation process and migrate to lymphoid organs, where they present pathogen-derived Ags to T cells. DC migration depends on tight regulation of the actin cytoskeleton to permit rapid adaptation to environmental cues. We investigated the role of hematopoietic lineage cell-specific protein 1 (HS1), the hematopoietic homolog of cortactin, in regulating the actin cytoskeleton of murine DCs. HS1 localized to lamellipodial protrusions and podosomes, actin-rich structures associated with adhesion and migration. DCs from HS1(−/−) mice showed aberrant lamellipodial dynamics. Moreover, although these cells formed recognizable podosomes, their podosome arrays were loosely packed and improperly localized within the cell. HS1 interacts with Wiskott-Aldrich Syndrome protein (WASp), another key actin-regulatory protein, through mutual binding to WASp-interacting protein. Comparative analysis of DCs deficient for HS1, WASp or both proteins revealed unique roles for these proteins in regulating podosomes with WASp being essential for podosome formation and with HS1 ensuring efficient array organization. WASp recruitment to podosome cores was independent of HS1, whereas HS1 recruitment required Src homology 3 domain-dependent interactions with the WASp/WASp-interacting protein heterodimer. In migration assays, the phenotypes of HS1- and WASp-deficient DCs were related, but distinct. WASp(−/y) DCs migrating in a chemokine gradient showed a large decrease in velocity and diminished directional persistence. In contrast, HS1(−/−) DCs migrated faster than wild-type cells, but directional persistence was significantly reduced. These studies show that HS1 functions in concert with WASp to fine-tune DC cytoarchitecture and direct cell migration
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