752 research outputs found

    An optimal location strategy for Internet sellers in markets with different tax rates

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    The traditional view that a high sales tax rate reduces trade by driving a wedge between the purchase and sale price may not apply to internet commerce for two reasons. The first reason is that the sales tax paid by buyers purchasing via the internet is determined by the tax rate in the region of the buyer. The second reason is that a high sales tax may lower the before-tax price if sellers absorb part of the tax. Taken together, this implies that internet distributors may profitably target customers in regions with low tax rates by locating their selling addresses in high tax regions. Consequently the optimal marketing strategy for a global internet distributor may include siting selling locations in regions with high tax rates in order to target customers in regions with low tax rates. An empirical analysis of the European car market suggests that this is more than a remote theoretical possibility by demonstrating that the before-tax prices recommended by manufacturers for new cars are lower in high tax countries

    Short-run and long-run determinants of the price of gold

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    In 1833 the price of gold was 20.65perounce,about20.65 per ounce, about 415 in 2005 terms, while in 2005 the actual price of gold was $445 - a very small change in the real price of gold over a period of one hundred and seventy two years. Despite this apparent constancy in real terms over the long run, it is also true that, outside of periods when the gold price was fixed through various iterations of the gold standard, it has fluctuated significantly in the shorter term, sometimes for years at a time. Can these two apparently contradictory realities be reconciled? And can one be sure that the long run positive relationship between gold and inflation has persisted beyond the era of Bretton Woods? Indeed, is there any credence to the claim that gold can be used as a long-run hedge against inflation? The results reported in this paper provide some answers to these questions that are so central to the gold market and its many participants around the world. We also address the inflation hedging properties of gold in the currencies of the major gold-consuming countries outside of the USA, taking into account both the domestic exchange rate relative to the dollar and domestic consumer price index movements. Real gold prices denominated in the home currency of investors outside of the USA also deviate in the short-run from their home country inflation hedge price and there is also a long-run tendency for gold prices to revert to the long-run hedge price. The major gold consuming countries outside of the USA, that is, India, China, Turkey, Saudi Arabia and Indonesia were rational to purchase gold in that it proved more than adequate as an inflation hedge. For these countries the actual USA dollar gold price between 1976 and 2005 far exceeded the dollar gold price required to provide an inflation hedge after taking account of exchange rates between the US dollar and the home country and the home country consumer price index movements

    Dynamics and distribution of natural and human-caused hypoxia

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    Water masses can become undersaturated with oxygen when natural processes alone or in combination with anthropogenic processes produce enough organic carbon that is aerobically decomposed faster than the rate of oxygen re-aeration. The dominant natural processes usually involved are photosynthetic carbon production and microbial respiration. The re-supply rate is indirectly related to its isolation from the surface layer. Hypoxic water masses (\u3c 2 mg L-1, or approximately 30% saturation) can form, therefore, under \u27natural\u27 conditions, and are more likely to occur in marine systems when the water residence time is extended, water exchange and ventilation are minimal, stratification occurs, and where carbon production and export to the bottom layer are relatively high. Hypoxia has occurred through geological time and naturally occurs in oxygen minimum zones, deep basins, eastern boundary upwelling systems, and fjords. Hypoxia development and continuation in many areas of the world\u27s coastal ocean is accelerated by human activities, especially where nutrient loading increased in the Anthropocene. This higher loading set in motion a cascading set of events related to eutrophication. The formation of hypoxic areas has been exacerbated by any combination of interactions that increase primary production and accumulation of organic carbon leading to increased respiratory demand for oxygen below a seasonal or permanent pycnocline. Nutrient loading is likely to increase further as population growth and resource intensification rises, especially with increased dependency on crops using fertilizers, burning of fossil fuels, urbanization, and waste water generation. It is likely that the occurrence and persistence of hypoxia will be even more widespread and have more impacts than presently observed. Global climate change will further complicate the causative factors in both natural and human-caused hypoxia. The likelihood of strengthened stratification alone, from increased surface water temperature as the global climate warms, is sufficient to worsen hypoxia where it currently exists and facilitate its formation in additional waters. Increased precipitation that increases freshwater discharge and flux of nutrients will result in increased primary production in the receiving waters up to a point. The interplay of increased nutrients and stratification where they occur will aggravate and accelerate hypoxia. Changes in wind fields may expand oxygen minimum zones onto more continental shelf areas. On the other hand, not all regions will experience increased precipitation, some oceanic water temperatures may decrease as currents shift, and frequency and severity of tropical storms may increase and temporarily disrupt hypoxia more often. The consequences of global warming and climate change are effectively uncontrollable at least in the near term. On the other hand, the consequences of eutrophication-induced hypoxia can be reversed if long-term, broad-scale, and persistent efforts to reduce substantial nutrient loads are developed and implemented. In the face of globally expanding hypoxia, there is a need for water and resource managers to act now to reduce nutrient loads to maintain, at least, the current status

    Regulation of haemopoietic stem‐cell proliferation in mice carrying the Slj allele

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    We investigated a haemopoietic stromal defect, in mice heterozygous for the Slj allele, during haemopoietic stress induced by treatment with bacterial lipopolysaccharides (LPS) or lethal total body irradiation (TBI) and bone‐marrow cell (BMC) reconstitution. Both treatments resulted in a comparable haemopoietic stem cell (CFU‐s) proliferation in Slj/+ and +/+ haemopoietic organs. There was no difference in committed haemopoietic progenitor cell (BFU‐e and CFU‐G/M) kinetics after TBI and +/+ bone‐marrow transplantation in Slj/+ and +/+ mice. the Slj/+ mice were deficient in their ability to support macroscopic spleen colony formation (65% of +/+ controls) as measured at 7 and 10 days after BMC transplantation. However, the Slj/+ spleen colonies contained the same number of BFU‐E and CFU‐G/M as colonies from +/+ spleens, while their CFU‐s content was increased. On day 10 post‐transplantation, the macroscopic ‘missing’ colonies could be detected at the microscopic level. These small colonies contained far fewer CFU‐s than the macroscopic detectable colonies. Analysis of CFU‐s proliferation‐inducing activities in control and post‐LPS sera revealed that Slj/+ mice are normal in their ability to produce and to respond to humoral stem‐cell regulators. We postulate that Slj/+ mice have a normal number of splenic stromal ‘niches’ for colony formation. However, 35% of these niches is defective in its proliferative support. Copyrigh

    Overcoming controllability problems in distributed testing from an input output transition system

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    This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 Springer VerlagThis paper concerns the testing of a system with physically distributed interfaces, called ports, at which it interacts with its environment. We place a tester at each port and the tester at port p observes events at p only. This can lead to controllability problems, where the observations made by the tester at a port p are not sufficient for it to be able to know when to send an input. It is known that there are test objectives, such as executing a particular transition, that cannot be achieved if we restrict attention to test cases that have no controllability problems. This has led to interest in schemes where the testers at the individual ports send coordination messages to one another through an external communications network in order to overcome controllability problems. However, such approaches have largely been studied in the context of testing from a deterministic finite state machine. This paper investigates the use of coordination messages to overcome controllability problems when testing from an input output transition system and gives an algorithm for introducing sufficient messages. It also proves that the problem of minimising the number of coordination messages used is NP-hard

    Mass-losing accretion discs around supermassive black holes

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    We study the effects of outflow/wind on the gravitational stability of accretion discs around supermassive black holes using a set of analytical steady-state solutions. Mass-loss rate by the outflow from the disc is assumed to be a power-law of the radial distance and the amount of the energy and the angular momentum which are carried away by the wind are parameterized phenomenologically. We show that the mass of the first clumps at the self-gravitating radius linearly decreases with the total mass-loss rate of the outflow. Except for the case of small viscosity and high accretion rate, generally, the self-gravitating radius increases as the amount of mass-loss by the outflow increases. Our solutions show that as more angular momentum is lost by the outflow, then reduction to the mass of the first clumps is more significant.Comment: Accepted for publication in Astrophysics & Space Scienc

    Martensitic transition and magnetoresistance in a Cu-Al-Mn shape memory alloy. Influence of aging

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    We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a bccbcc-based (β\beta-phase) towards a close-packed structure (MM-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the MM- and β\beta-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu2_2AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the β\beta- and MM-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu2_2MnAl-rich domains that do not transform martensitically.Comment: 9 pages, 9 figures, accepted for publication in PR

    Antecedents and outcomes of consumer environmentally friendly attitudes and behaviour

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    With the intensification of problems relating to the environment, a growing number of consumers are becoming more ecologically conscious in their preferences and purchases of goods. This paper presents the results of a study conducted among 500 Cypriot consumers, focusing on the factors that shape consumer environmental attitudes and behaviour, as well as on the resulting outcomes. The findings confirmed that both the inward and outward environmental attitudes of a consumer are positively influenced by his/her degree of collectivism, long-term orientation, political involvement, deontology, and law obedience, but have no connection with liberalism. The adoption of an inward environmental attitude was also found to be conducive to green purchasing behaviour that ultimately leads to high product satisfaction. On the other hand, an outward environmental attitude facilitates the adoption of a general environmental behaviour, which is responsible for greater satisfaction with life. The findings of the study have important implications for shaping effective company offerings to consumers in target markets, as well as formulating appropriate policies at the governmental level to enhance environmental sensitivity among citizens

    Nonperturbative Effects in Gluon Radiation and Photoproduction of Quark Pairs

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    We introduce a nonperturbative interaction for light-cone fluctuations containing quarks and gluons. The qˉq\bar qq interaction squeezes the transverse size of these fluctuations in the photon and one does not need to simulate this effect via effective quark masses. The strength of this interaction is fixed by data. Data on diffractive dissociation of hadrons and photons show that the nonperturbative interaction of gluons is much stronger. We fix the parameters for the nonperturbative quark-gluon interaction by data for diffractive dissociation to large masses (triple-Pomeron regime). This allows us to predict nuclear shadowing for gluons which turns out to be not as strong as perturbative QCD predicts. We expect a delayed onset of gluon shadowing at x102x \leq 10^{-2} shadowing of quarks. Gluon shadowing turns out to be nearly scale invariant up to virtualities Q24GeV2Q^2\sim 4 GeV^2 due to presence of a semihard scale characterizing the strong nonperturbative interaction of gluons. We use the same concept to improve our description of gluon bremsstrahlung which is related to the distribution function for a quark-gluon fluctuation and the interaction cross section of a qˉqG\bar qqG fluctuation with a nucleon. We expect the nonperturbative interaction to suppress dramatically the gluon radiation at small transverse momenta compared to perturbative calculations.Comment: 58 pages of Latex including 11 figures. Shadowing for soft gluons and Fig. 6 are added as well as a few reference

    The Sunrise Mission

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    The first science flight of the balloon-borne \Sunrise telescope took place in June 2009 from ESRANGE (near Kiruna/Sweden) to Somerset Island in northern Canada. We describe the scientific aims and mission concept of the project and give an overview and a description of the various hardware components: the 1-m main telescope with its postfocus science instruments (the UV filter imager SuFI and the imaging vector magnetograph IMaX) and support instruments (image stabilizing and light distribution system ISLiD and correlating wavefront sensor CWS), the optomechanical support structure and the instrument mounting concept, the gondola structure and the power, pointing, and telemetry systems, and the general electronics architecture. We also explain the optimization of the structural and thermal design of the complete payload. The preparations for the science flight are described, including AIV and ground calibration of the instruments. The course of events during the science flight is outlined, up to the recovery activities. Finally, the in-flight performance of the instrumentation is briefly summarized.Comment: 35 pages, 17 figure
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