467 research outputs found

    Efficient Integer Coefficient Search for Compute-and-Forward

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    Integer coefficient selection is an important decoding step in the implementation of compute-and-forward (C-F) relaying scheme. Choosing the optimal integer coefficients in C-F has been shown to be a shortest vector problem (SVP) which is known to be NP hard in its general form. Exhaustive search of the integer coefficients is only feasible in complexity for small number of users while approximation algorithms such as Lenstra-Lenstra-Lovasz (LLL) lattice reduction algorithm only find a vector within an exponential factor of the shortest vector. An optimal deterministic algorithm was proposed for C-F by Sahraei and Gastpar specifically for the real valued channel case. In this paper, we adapt their idea to the complex valued channel and propose an efficient search algorithm to find the optimal integer coefficient vectors over the ring of Gaussian integers and the ring of Eisenstein integers. A second algorithm is then proposed that generalises our search algorithm to the Integer-Forcing MIMO C-F receiver. Performance and efficiency of the proposed algorithms are evaluated through simulations and theoretical analysis.Comment: IEEE Transactions on Wireless Communications, to appear.12 pages, 8 figure

    Tax-Loss Harvesting with Cryptocurrencies

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    This study describes the landscape of taxation in the crypto markets concerning U.S. taxpayers, and examines how recent increases in tax scrutiny have lead to changes in trading behavior by crypto traders. Using a conceptual framework, we predict and find that increased tax scrutiny leads crypto investors to utilize legal tax planning with tax-loss harvesting as an alternative to non-compliance. In particular, domestic traders increase compliance and tax-loss harvesting following the increase in tax scrutiny, and U.S. exchanges exhibit a significantly greater amount of wash trading. Additional findings suggest that broad-based and targeted changes in tax scrutiny can differentially affect crypto traders’ preference for U.S.-based exchanges. We discuss new gray areas for tax regulation relating to new crypto assets such as Non-Fungible Tokens and Decentralized Finance protocols that highlight the importance of the coordination between tax policy and other regulations

    Immune-Boosting Functional Foods: A Potential Remedy for Chinese Consumers Living Under Polluted Air

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    The deterioration of air quality in China has resulted in many people looking for remedies to counteract the impact that air pollution is perceived to be having on their health. As the importance of diet on immune health is becoming increasingly well recognised, a narrative literature review was undertaken to elucidate Chinese consumers’ acceptance of functional food products designed to help the immune system recover from pollution-driven impact and to assess their market potential. Consumers’ attitude towards immune-boosting functional foods were mainly positive, with scientific validation being important in determining the credibility of a product. This was despite the fact that the effectiveness of the functional food products currently in the market that purported to be remedies for pollution-driven impacts on the lung did not appear to be supported by scientific evidence. Numerous studies have reported functional foods could provide a wide range of benefits to immune health, including helping pollution-driven immune issues. This review highlights the market demand for effective and scientifically-proven functional food products that help Chinese consumers’ immune system recover from the impact of air pollution

    Type‐Preserving CPS Translation of Σ and Π Types is Not Not Possible

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    International audienceDependently typed languages like Coq are used to specify and prove functional correctness of source programs,but what we ultimately need are guarantees about correctness of compiled code. By preserving dependenttypes through each compiler pass, we could preserve source-level specifications and correctness proofs intothe generated target-language programs. Unfortunately, type-preserving compilation of dependent types isnontrivial. In 2002, Barthe and Uustalu showed that type-preserving CPS is not possible for languages likeCoq. Specifically, they showed that for strong dependent pairs (Σ types), the standard typed call-by-name CPSis not type preserving. They further proved that for dependent case analysis on sums, a class of typed CPStranslations—including the standard translation—is not possible. In 2016, Morrisett noticed a similar problemwith the standard call-by-value CPS translation for dependent functions (Π types). In essence, the problem isthat the standard typed CPS translation by double-negation, in which computations are assigned types of theform (A → ⊥) → ⊥, disrupts the term/type equivalence that is used during type checking in a dependentlytyped language.In this paper, we prove that type-preserving CPS translation for dependently typed languages is not notpossible. We develop both call-by-name and call-by-value CPS translations from the Calculus of Constructionswith both Π and Σ types (CC) to a dependently typed target language, and prove type preservation andcompiler correctness of each translation. Our target language is CC extended with an additional equivalencerule and an additional typing rule, which we prove consistent by giving a model in the extensional Calculus ofConstructions. Our key observation is that we can use a CPS translation that employs answer-type polymorphism,where CPS-translated computations have type ∀α.(A → α) → α. This type justifies, by a free theorem,the new equality rule in our target language and allows us to recover the term/type equivalences that CPStranslation disrupts. Finally, we conjecture that our translation extends to dependent case analysis on sums,despite the impossibility result, and provide a proof sketch

    A protein knockdown strategy to study the function of β-catenin in tumorigenesis

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    BACKGROUND: The Wnt signaling pathway plays critical roles in cell proliferation and cell fate determination at many stages of development. A critical downstream target of Wnt signaling is the cytosolic β-catenin, which is stabilized upon Wnt activation and promotes transcription of a variety of target genes including c-myc and cyclin D. Aberrant Wnt signaling, which results from mutations of either β-catenin or adenomatous polyposis coli (APC), renders β-catenin resistant to degradation, and has been associated with multiple types of human cancers. RESULTS: A protein knockdown strategy was designed to reduce the cytosolic β-catenin levels through accelerating its turnover rate. By engineering a chimeric protein with the β-catenin binding domain of E-cadherin fused to βTrCP ubiquitin-protein ligase, the stable β-catenin mutant was recruited to the cellular SCF (Skp1, Cullin 1, and F-box-containing substrate receptor) ubiquitination machinery for ubiquitination and degradation. The DLD1 colon cancer cells express wild type β-catenin at abnormally high levels due to loss of APC. Remarkably, conditional expression of βTrCP-E-cadherin under the control of a tetracycline-repressive promoter in DLD1 cells selectively knocked down the cytosolic, but not membrane-associated subpopulation of β-catenin. As a result, DLD1 cells were impaired in their growth and clonogenic ability in vitro, and lost their tumorigenic potential in nude mice. CONCLUSION: We have designed a novel approach to induce degradation of stabilized/mutated β-catenin. Our results suggest that a high concentration of cytoplasmic β-catenin is critical for the growth of colorectal tumor cells. The protein knockdown strategy can be utilized not only as a novel method to dissect the role of oncoproteins in tumorigenesis, but also as a unique tool to delineate the function of a subpopulation of proteins localized to a specific subcellular compartment

    A MULTIPHASE FLOW LOOP DESIGN FOR INVESTIGATING THE PARTIAL PHASE SEPARATION IN A PIPE TEE

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    This article presents a design and commissioning of a multiphase flow loop, which was developed for scrutinizing the partial phase separation characteristics of pipe Tees. Its length is 9m and its primary diameter is 0.078m (3 inches). For the ease of modification, its design was kept modular, so that it could be used for testing various other pipe profiles. To validate this flow loop, the separation of a stratified-wavy flow was tested in a regular diameter ratio pipe Tee, and the gathered results were compared with previously published data. A good agreement was observed between the two data sources, which suggests that this flow loop is suitable for a further experimentation

    Selection of Depression Measures for Use among Vietnamese Populations in Primary Care Settings: A Scoping Review

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    Depression is an important and growing contributor to the burden of disease around the world and evidence suggests the experience of depression varies cross-culturally. Efforts to improve the integration of services for depression in primary care are increasing globally, meaning that culturally valid measures that are acceptable for use in primary care settings are needed. We conducted a scoping review of 27 studies that validated or used 10 measures of depression in Vietnamese populations. We reviewed the validity of the instruments as reported in the studies and qualitatively assessed cultural validity and acceptability for use in primary care. We found much variation in the methods used to validate the measures, with an emphasis on criterion validity and reliability. Enhanced evaluation of content and construct validity is needed to ensure validity within diverse cultural contexts such as Vietnam. For effective use in primary care, measures must be further evaluated for their brevity and ease of use. To identify appropriate measures for use in primary care in diverse populations, assessment must balance standard validity testing with enhanced testing for appropriateness in terms of culture, language, and gender and for acceptability for use in primary care
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