4,088 research outputs found

    Observing the Structure of the Landscape with the CMB Experiments

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    Assuming that inflation happened through a series of tunneling in the string theory landscape, it is argued that one can determine the structure of vacua using precise measurements of the scalar spectral index and tensor perturbations at large scales. It is shown that for a vacuum structure where the energy gap between the minima is constant, i.e. ϵi=imf4\epsilon_i=i m_f^4, one obtains the scalar spectral index, nsn_s, to be ≃0.9687\simeq 0.9687, for the modes that exit the horizon 60 e-folds before the end of inflation. Alternatively, for a vacuum structure in which the energy gap increases linearly with the vacuum index, i.e. ϵi=i22mf4\epsilon_i=\frac{i^2}{2} m_f^4, nsn_s turns out to be ≃0.9614\simeq 0.9614. Both these two models are motivated within the string theory landscape using flux-compactification and their predictions for scalar spectral index are compatible with WMAP results. For both these two models, the results for the scalar spectral index turn out to be independent of mfm_f. Nonetheless, assuming that inflation started at Planckian energies and that there had been successful thermalization at each step, one can constrain mf<2.6069×10−5mPm_f<2.6069\times 10^{-5} m_P and mf<6.5396×10−7mPm_f<6.5396\times 10^{-7} m_P in these two models, respectively. Violation of the single-field consistency relation between the tensor and scalar spectra is another prediction of chain inflation models. This corresponds to having a smaller tensor/scalar ratio at large scales in comparison with the slow-roll counterparts. Similar to slow-roll inflation, it is argued that one can reconstruct the vacuum structure using the CMB experiments.Comment: v1: 8 pages, 2 figures; v2: grammatical typos corrected, results unchanged v3: To be published in JCA

    Global Auditing and Accounting Confusion

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    The article discusses about the accounting and audit standards in the United States, which is different from one country to another due to business practices, fiscal systems and the law regulating a company. The International Federation of Accountants and the International Accounting Standards Committee aimed to a have a consistency of audit and accounting standards around the world, although these diversities can easily identify a company\u27s national origin and as a basis of the financial statements presentation

    Raising Capital Overseas

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    The article states that more and more companies are trying to raise capital by listing their securities for sale on foreign exchanges.More and more companies are trying to raise capital by listing their securities for sale on foreign exchanges. However, the way financial statements are prepared varies from one country to the next. U.S. companies looking to raise capital abroad must consider the myriad rules regarding financial statement presentation just as foreign companies listing stock in the United States must adhere to the rules and regulations of the Securities and Exchange Commission. Similarly, the costs of reconciling U.S. accounting standards to adhere to foreign standards also can be high, so it is important that U.S. companies know the questions they will face when going global. Although the details of additional disclosures must be determined case by case, they can be developed in the context of normal corporate reporting. However, U.S. public companies should determine the nature and extent of additional disclosures in advance to provide for an orderly approach to corporate reporting and to avoid any undue delay in the listing process

    Desensitizing Inflation from the Planck Scale

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    A new mechanism to control Planck-scale corrections to the inflationary eta parameter is proposed. A common approach to the eta problem is to impose a shift symmetry on the inflaton field. However, this symmetry has to remain unbroken by Planck-scale effects, which is a rather strong requirement on possible ultraviolet completions of the theory. In this paper, we show that the breaking of the shift symmetry by Planck-scale corrections can be systematically suppressed if the inflaton field interacts with a conformal sector. The inflaton then receives an anomalous dimension in the conformal field theory, which leads to sequestering of all dangerous high-energy corrections. We analyze a number of models where the mechanism can be seen in action. In our most detailed example we compute the exact anomalous dimensions via a-maximization and show that the eta problem can be solved using only weakly-coupled physics.Comment: 34 pages, 3 figures

    Vertebrate Natural History Notes from Arkansas, 2017

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    Because meaningful observations of natural history are not always part of larger studies, important pieces of information often are unreported. Small details, however, can fills gaps in understanding and also lead to interesting questions about ecological relationships or environmental change. We have compiled recent observations of foods, reproduction, record size, parasites, and distribution of 30 species of fishes, new records of distribution and parasites of 2 species of amphibians, and new records of distribution, parasites, reproduction and anomalies of 11 species of mammals

    Preliminary evidence of increased striatal dopamine in a nonhuman primate model of maternal immune activation.

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    Women exposed to a variety of viral and bacterial infections during pregnancy have an increased risk of giving birth to a child with autism, schizophrenia or other neurodevelopmental disorders. Preclinical maternal immune activation (MIA) models are powerful translational tools to investigate mechanisms underlying epidemiological links between infection during pregnancy and offspring neurodevelopmental disorders. Our previous studies documenting the emergence of aberrant behavior in rhesus monkey offspring born to MIA-treated dams extends the rodent MIA model into a species more closely related to humans. Here we present novel neuroimaging data from these animals to further explore the translational potential of the nonhuman primate MIA model. Nine male MIA-treated offspring and 4 controls from our original cohort underwent in vivo positron emission tomography (PET) scanning at approximately 3.5-years of age using [18F] fluoro-l-m-tyrosine (FMT) to measure presynaptic dopamine levels in the striatum, which are consistently elevated in individuals with schizophrenia. Analysis of [18F]FMT signal in the striatum of these nonhuman primates showed that MIA animals had significantly higher [18F]FMT index of influx compared to control animals. In spite of the modest sample size, this group difference reflects a large effect size (Cohen's d = 0.998). Nonhuman primates born to MIA-treated dams exhibited increased striatal dopamine in late adolescence-a hallmark molecular biomarker of schizophrenia. These results validate the MIA model in a species more closely related to humans and open up new avenues for understanding the neurodevelopmental biology of schizophrenia and other neurodevelopmental disorders associated with prenatal immune challenge
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