644 research outputs found

    A Simple and Flexible Dynamic Approach to Foreign Direct Investment Growth: The Canada-United States Relationship in the Context of Free Trade.

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    This paper asks a simple question: Did Wilfred Laurier’s dream of free trade with the United States, when it came to fruition in 1989, also impact on foreign direct investment (FDI) into Canada by US multinationals? This paper argues that the customary static econometric approach found in the FDI literature, along with the assumption that policy changes influence only the intercept term, are inadequate to address the question. Instead we introduce an innovative dynamic framework to support the testing of hypotheses on behavioural changes in the variables using a structural break framework. A key conclusion is that prior to signing the free trade agreement US FDI responded only to current growth in the Canadian economy, in a unitary fashion, and current exchange rate shifts. This can be described as a static relationship. The implementation of the free trade agreements between Canada and the USA increased the responsiveness of US FDI to growth in the Canadian economy by a factor greater than two. Furthermore, dynamics are found in the form of a lagged effect for changes in the growth in the Canadian economy and interest rate differentials. These conclusions challenge the dominant view, including that in official policy circles, that the free trade agreement had no impact on US firms’ FDI decisions in Canada. Note: Previous versions of this paper were entitled: “A Simple and Flexible Dynamic Approach to Foreign Direct Investment Growth: Did Canada Benefit From the Free Trade Agreements with the United States?”Canada-United States, foreign direct investment, empirical relationship

    Identification of mitogen-activated protein kinase docking sites in enzymes that metabolize phosphatidylinositols and inositol phosphates

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    Background: Reversible interactions between the components of cellular signaling pathways allow for the formation and dissociation of multimolecular complexes with spatial and temporal resolution and, thus, are an important means of integrating multiple signals into a coordinated cellular response. Several mechanisms that underlie these interactions have been identified, including the recognition of specific docking sites, termed a D-domain and FXFP motif, on proteins that bind mitogen-activated protein kinases (MAPKs). We recently found that phosphatidylinositol-specific phospholipase C-γ1 (PLC-γ1) directly binds to extracellular signal-regulated kinase 2 (ERK2), a MAPK, via a D-domain-dependent mechanism. In addition, we identified D-domain sequences in several other PLC isozymes. In the present studies we sought to determine whether MAPK docking sequences could be recognized in other enzymes that metabolize phosphatidylinositols (PIs), as well as in enzymes that metabolize inositol phosphates (IPs). Results: We found that several, but not all, of these enzymes contain identifiable D-domain sequences. Further, we found a high degree of conservation of these sequences and their location in human and mouse proteins; notable exceptions were PI 3-kinase C2-γ, PI 4-kinase type IIβ, and inositol polyphosphate 1- phosphatase. Conclusion: The results indicate that there may be extensive crosstalk between MAPK signaling and signaling pathways that are regulated by cellular levels of PIs or IPs

    Stable Frank-Kasper phases of self-assembled, soft matter spheres

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    Single molecular species can self-assemble into Frank Kasper (FK) phases, finite approximants of dodecagonal quasicrystals, defying intuitive notions that thermodynamic ground states are maximally symmetric. FK phases are speculated to emerge as the minimal-distortional packings of space-filling spherical domains, but a precise quantitation of this distortion and how it affects assembly thermodynamics remains ambiguous. We use two complementary approaches to demonstrate that the principles driving FK lattice formation in diblock copolymers emerge directly from the strong-stretching theory of spherical domains, in which minimal inter-block area competes with minimal stretching of space-filling chains. The relative stability of FK lattices is studied first using a diblock foam model with unconstrained particle volumes and shapes, which correctly predicts not only the equilibrium {\sigma} lattice, but also the unequal volumes of the equilibrium domains. We then provide a molecular interpretation for these results via self-consistent field theory, illuminating how molecular stiffness regulates the coupling between intra-domain chain configurations and the asymmetry of local packing. These findings shed new light on the role of volume exchange on the formation of distinct FK phases in copolymers, and suggest a paradigm for formation of FK phases in soft matter systems in which unequal domain volumes are selected by the thermodynamic competition between distinct measures of shape asymmetry.Comment: 40 pages, 22 figure

    Cetacean exploitation in Roman and medieval London:Reconstructing whaling activities by applying zooarchaeological, historical, and biomolecular analysis

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    Cetacean (whale, dolphin, and porpoise) remains are occasionally encountered at Roman and medieval sites in London and are regularly the topic of medieval historical sources. These sources are often concerned with whale strandings and the subsequent claims on the carcass by the king, queen, or other members of the nobility or clergy with jurisdiction over the coastline that the whale stranded upon. The meat stripped from the carcasses was regularly transported to London and cetaceans have therefore been ascribed as a “high-status food source”. Besides, strandings, several historical sources also suggest that active whaling was undertaken, and that meat was sold at several London markets. Based on these historical sources it however remains unclear to what extent active whaling was undertaken, and which species were exploited. Zooarchaeological studies address whales and their role in Roman and medieval society more directly through the study of animal bones. This study combines historical sources and the identification of zooarchaeological cetacean remains from the London sites of Bermondsey Abbey, Westminster Abbey (cellarium), Winchester Palace, Vintry, St Peter’s Hill, and Trig Lane through Zooarchaeology by Mass Spectrometry (ZooMS) and morphological analysis. The historical and zooarchaeological evidence from London indicates that cetacean meat was indeed associated with a high-status diet, in particular the ecclesiastical diet, though some form of commercialization of cetacean meat also took place. On occasion, whale bone was used for the creation of bone artefacts or tools, primarily during the Middle Saxon period. Additionally, it is suggested that active whaling might occasionally have been undertaken, potentially already from the Middle Saxon period onwards. However, the majority of the remains were probably acquired through opportunistic scavenging of stranded individuals

    Identification of mitogen-activated protein kinase docking sites in enzymes that metabolize phosphatidylinositols and inositol phosphates

    Get PDF
    BACKGROUND: Reversible interactions between the components of cellular signaling pathways allow for the formation and dissociation of multimolecular complexes with spatial and temporal resolution and, thus, are an important means of integrating multiple signals into a coordinated cellular response. Several mechanisms that underlie these interactions have been identified, including the recognition of specific docking sites, termed a D-domain and FXFP motif, on proteins that bind mitogen-activated protein kinases (MAPKs). We recently found that phosphatidylinositol-specific phospholipase C-γ1 (PLC-γ1) directly binds to extracellular signal-regulated kinase 2 (ERK2), a MAPK, via a D-domain-dependent mechanism. In addition, we identified D-domain sequences in several other PLC isozymes. In the present studies we sought to determine whether MAPK docking sequences could be recognized in other enzymes that metabolize phosphatidylinositols (PIs), as well as in enzymes that metabolize inositol phosphates (IPs). RESULTS: We found that several, but not all, of these enzymes contain identifiable D-domain sequences. Further, we found a high degree of conservation of these sequences and their location in human and mouse proteins; notable exceptions were PI 3-kinase C2-γ, PI 4-kinase type IIβ, and inositol polyphosphate 1-phosphatase. CONCLUSION: The results indicate that there may be extensive crosstalk between MAPK signaling and signaling pathways that are regulated by cellular levels of PIs or IPs

    Molecular antimicrobial resistance surveillance for neisseria gonorrhoeae, Northern Territory, Australia

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    Neisseria gonorrhoeae antimicrobial resistance (AMR) is a globally recognized health threat; new strategies are needed to enhance AMR surveillance. The Northern Territory of Australia is unique in that 2 different first-line therapies, based primarily on geographic location, are used for gonorrhea treatment. We tested 1,629 N. gonorrhoeae nucleic acid amplification test–positive clinical samples, collected from regions where ceftriaxone plus azithromycin or amoxicillin plus azithromycin are recommended first-line treatments, by using 8 N. gonorrhoeae AMR PCR assays. We compared results with those from routine culture-based surveillance data. PCR data confirmed an absence of ceftriaxone resistance and a low level of azithromycin resistance (0.2%), and that penicillin resistance was \u3c5% in amoxicillin plus azithromycin regions. Rates of ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae were lower when molecular methods were used. Molecular methods to detect N. gonorrhoeae AMR can increase the evidence base for treatment guidelines, particularly in settings where culture-based surveillance is limited

    The detuning effects of a wrist-worn antenna and design of a custom antenna measurement system

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    This paper investigates the effects of antenna detuning on wireless devices caused by the presence of the human body,particularly the wrist. To facilitate repeatable and consistent antenna impedance measurements, an accurate and low cost human phantom arm, that simulates human tissue at 433MHz frequencies, has been developed and characterized. An accurate and low cost hardware prototype system has been developed to measure antenna return loss at a frequency of 433MHz and the design, fabrication and measured results are presented. This system provides a flexible means of evaluating closed-loop reconfigurable antenna tuning circuits for use in wireless mote applications
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