1,496 research outputs found

    Multi-field open inflation model and multi-field dynamics in tunneling

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    We consider a multi-field open inflation model, in which one of the fields dominates quantum tunneling from a false vacuum while the other field governs slow-roll inflation within the bubble nucleated from false vacuum decay. We call the former the tunneling field and the latter the inflaton field. In the limit of a negligible interaction between the two fields, the false vacuum decay is described by a Coleman-De Luccia instanton. Here we take into account the coupling between the two fields and construct explicitly a multi-field instanton for a simple quartic potential model. We also solve the evolution of the scalar fields within the bubble. We find our model realizes open inflation successfully. This is the first concrete, viable model of open inflation realized with a simple potential. We then study the effect of the multi-field dynamics on the false vacuum decay, specifically on the tunneling rate. We find the tunneling rate increases in general in comparison with the single field case, though the increase is small unless the inflaton affects the instanton solution substantially.Comment: 13 pages, 4 figure

    The Economics of Pricing Network Interconnection: Theory and Application to the Market for Telecommunications in New Zealand

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    Deregulation and the successful introduction of competition to the market for telephone services raise the complex issue of interconnection. Incumbent telephone companies have an incentive to maximize profits by charging entrants the highest interconnection price possible. In New Zealand, the debate over the proper terms of interconnection was brought before the courts under the country\u27s antitrust laws. The incumbent attempted to establish the parity principle as the standard for interconnection. As proposed in New Zealand, the parity principle would allow an unregulated monopolist to set access charges at a level sufficient to compensate it for the financial consequences of entry. Justification for this standard lies in claims that any other interconnection rule would be inefficient. Tye and Lapuerta critique these efficiency claims. They argue that the proposed rule would frustrate goals of competition, including: constraining monopoly pricing, enhancing dynamic efficiency and encouraging technological progress. The authors reject the parity principle in favor of a proposal that compensates rival networks for terminating inter-network calls on the basis of long-run incremental cost. They explain how interconnection on these terms can simultaneously promote successful competition and efficiency in the provision of telephone service

    Exploring a string-like landscape

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    We explore inflationary trajectories within randomly-generated two-dimensional potentials, considered as a toy model of the string landscape. Both the background and perturbation equations are solved numerically, the latter using the two-field formalism of Peterson and Tegmark which fully incorporates the effect of isocurvature perturbations. Sufficient inflation is a rare event, occurring for only roughly one in 10510^5 potentials. For models generating sufficient inflation, we find that the majority of runs satisfy current constraints from WMAP. The scalar spectral index is less than 1 in all runs. The tensor-to-scalar ratio is below the current limit, while typically large enough to be detected by next-generation CMB experiments and perhaps also by Planck. In many cases the inflationary consistency equation is broken by the effect of isocurvature modes.Comment: 24 pages with 8 figures incorporated, matches version accepted by JCA

    The Role of Gender and Emotions on Moral Hypocrisy

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    Recent studies have shown that the emotions of anger and guilt have interesting effects on an individual’s moral hypocrisy. Anger increasing the likelihood that one will be hypocritical and guilt effectively neutralizes any hypocritical tendencies. (Polman & Ruttan, 2012) We were keenly interested to see if we could duplicate these results at Ouachita and were also curious as to whether or not gender plays a role in how hypocritical a person will be. We wanted to know if emotion or gender could negatively impact logical reasoning because if they do, we could keep this in mind while making judgments in the future. We hypothesized that anger would show a significant effect for moral hypocrisy and that guilt would neutralize any tendencies towards moral hypocrisy. We also hypothesized that anger would affect men more than women

    The human gC1qR/p32 gene, C1qBP. Genomic organization and promoter analysis

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    gC1qR is an ubiquitously expressed cell protein that interacts with the globular heads of C1q (gC1q) and many other ligands. In this study, the 7.8-kilobase pair (kb) human gC1qPJp32 (C1qBP) gene was cloned and found to consist of 6 exons and 5 introns. Analysis of a 1.3-kb DNA fragment at the 5â€Č-flanking region of this gene revealed the presence of multiple TATA, CCAAT, and Sp1 binding sites. Luciferase reporter assays performed in different human cell lines demonstrated that the reporter gene was ubiquitously driven by this 1.3-kb fragment. Subsequent 5â€Č and 3â€Č deletion of this fragment confined promoter elements to within 400 base pairs (bp) upstream of the translational start site. Because the removal of the 8-bp consensus TATATATA at -399 to -406 and CCAAT at -410 to -414 did not significantly affect the transcription efficiency of the promoter, GC-rich sequences between this TATA box and the translation start site may be very important for the promoter activity of the C1qBP gene. One of seven GC-rich sequences in this region binds specifically to PANC-1 nuclear extracts, and the transcription factor Sp1 was shown to bind to this GC-rich sequence by the supershift assay. Primer extension analysis mapped three major transcription start regions. The farthest transcription start site is 49 bp upstream of the ATG translation initiation codon and is in close proximity of the specific SP1 binding site.postprin

    Reviews and syntheses: Spatial and temporal patterns in seagrass metabolic fluxes

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    Seagrass meadow metabolism has been measured for decades to gain insight into ecosystem energy, biomass production, food web dynamics, and, more recently, to inform its potential in ameliorating ocean acidification (OA). This extensive body of literature can be used to infer trends and drivers of seagrass meadow metabolism. Here, we synthesize the results from 56 studies reporting in situ rates of seagrass gross primary productivity, respiration, and/or net community productivity to highlight spatial and temporal variability in oxygen (O2) fluxes. We illustrate that daytime net community production (NCP) is positive overall and similar across seasons and geographies. Full-day NCP rates, which illustrate the potential cumulative effect of seagrass beds on seawater biogeochemistry integrated over day and night, were also positive overall but were higher in summer months in both tropical and temperate ecosystems. Although our analyses suggest seagrass meadows are generally autotrophic, the effects on seawater oxygen are relatively small in magnitude. We also find positive correlations between gross primary production and temperature, although this effect may vary between temperate and tropical geographies and may change under future climate scenarios if seagrasses approach thermal tolerance thresholds. In addition, we illustrate that periods when full-day NCP is highest could be associated with lower nighttime O2 and increased diurnal variability in seawater O2. These results can serve as first-order estimates of when and where OA amelioration by seagrasses may be likely. However, improved understanding of variations in NCPdic:NCPO2 ratios and increased work directly measuring metabolically driven alterations in seawater pH will further inform the potential for seagrass meadows to serve in this context

    Is Brane Inflation Eternal?

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    In this paper, we show that eternal inflation of the random walk type is generically absent in the brane inflationary scenario. Depending on how the brane inflationary universe originated, eternal inflation of the false vacuum type is still quite possible. Since the inflaton is the position of the D3-brane relative to the anti-D3-brane inside the compactified bulk with finite size, its value is bounded. In DBI inflation, the warped space also restricts the amplitude of the scalar fluctuation. These upper bounds impose strong constraints on the possibility of eternal inflation. We find that eternal inflation due to the random walk of the inflaton field is absent in both the KKLMMT slow roll scenario and the DBI scenario. A more careful analysis for the slow-roll case is also presented using the Langevin equation, which gives very similar results. We discuss possible ways to obtain eternal inflation of the random walk type in brane inflation. In the multi-throat brane inflationary scenario, the branes may be generated by quantum tunneling and roll out the throat. Eternal inflation of the false vacuum type inevitably happens in this scenario due to the tunneling process. Since these scenarios have different cosmological predictions, more data from the cosmic microwave background radiation will hopefully select the specific scenario our universe has gone through.Comment: 32 pages; v2: references and comments adde

    A radiation-like era before inflation

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    We show that the semiclassical approximation to the Wheeler-DeWitt equation for the minisuperspace of a minimally coupled scalar field in the spatially flat de Sitter Universe prompts the existence of an initial power-law evolution driven by non-adiabatic terms from the gravitational wavefunction which act like radiation. This simple model hence describes the onset of inflation from a previous radiation-like expansion during which the cosmological constant is already present but subleading.Comment: LaTeX, 8 pages, no figures; final version to be published in JCA

    Seeing motion and apparent motion

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    In apparent motion experiments, participants are presented with what is in fact a succession of two brief stationary stimuli at two different locations, but they report an impression of movement. Philosophers have recently debated whether apparent motion provides evidence in favour of a particular account of the nature of temporal experience. I argue that the existing discussion in this area is premised on a mistaken view of the phenomenology of apparent motion and, as a result, the space of possible philosophical positions has not yet been fully explored. In particular, I argue that the existence of apparent motion is compatible with an account of the nature of temporal experience that involves a version of direct realism. In doing so, I also argue against two other claims often made about apparent motion, viz. that apparent motion is the psychological phenomenon that underlies motion experience in the cinema, and that apparent motion is subjectively indistinguishable from real motion
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