4,088 research outputs found
Observing the Structure of the Landscape with the CMB Experiments
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. , one
obtains the scalar spectral index, , to be , 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. , turns out to be
. 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 . Nonetheless,
assuming that inflation started at Planckian energies and that there had been
successful thermalization at each step, one can constrain and 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
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
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
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
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.
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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