725 research outputs found
Superdeformation in Asymmetric NZ Nucleus Ar
A rotational band with five -ray transitions ranging from 2 to
12 states was identified in Ar. This band is linked through
transitions from the excited 2, 4 and 6 levels to
the low-lying states; this determines the excitation energy and the spin-parity
of the band. The deduced transition quadrupole moment of 1.45 indicates that the band has a superdeformed shape. The nature of the band
is revealed by cranked Hartree--Fock--Bogoliubov calculations and a
multiparticle--multihole configuration is assigned to the band
Higher Order Corrections to the Primordial Gravitational Wave Spectrum and its Impact on Parameter Estimates for Inflation
We study the impact of the use of the power series expression for the
primordial tensor spectrum on parameter estimation from future direct detection
gravitational wave experiments. The spectrum approximated by the power series
expansion may give large deviation from the true (fiducial) value when it is
normalized at CMB scale because of the large separation between CMB and direct
detection scales. We derive the coefficients of the higher order terms of the
expansion up to the sixth order within the framework of the slow-roll
approximation and investigate how well the inclusion of higher order terms
improves the analytic prediction of the spectrum amplitude by comparing with
numerical results. Using the power series expression, we consider future
constraints on inflationary parameters expected from direct detection
experiments of the inflationary gravitational wave background and show that the
truncation of the higher order terms can lead to incorrect evaluation of the
parameters. We present two example models; a quadratic chaotic inflation model
and mixed inflaton and curvaton model with a quartic inflaton potential.Comment: 25 pages, 7 figures, revised version accepted by JCA
Large igneous province activity drives oceanic anoxic event 2 environmental change across eastern Asia
During mid-Cretaceous Oceanic Anoxic Event 2, significant increase of atmospheric carbon dioxide concentrations from the eruption of the large igneous provinces is hypothesized to have induced a humid climate and an elevation in nutrient runoff from continents to the oceans, resulting in oxygen depletion in the ocean. However, hitherto there is limited insight into the driving factors of Oceanic Anoxic Event 2 from the Pacific and Asian continental margins, even though the former and the latter were the largest ocean and landmass at that time. Here, a multiproxy analysis for the Oceanic Anoxic Event 2 interval of the Yezo Group –deposited on northwestern Pacific along the active Asian continental margin– is interpretated to identify seven volcanic pulses, five of which may have elevated humidity, weathering intensity, and vegetational change in the eastern margin of Asia. Moreover, oxygen depletion occurred simultaneously in the northwest Pacific. Given that these environmental changes in the eastern margin of Asia were penecontemporaneous with the global carbon burial intervals during Oceanic Anoxic Event 2, the elevated nutrient supply from the Asian continental margin to the Pacific Ocean may have, in part, contributed to the worldwide depletion of oxygen of the ocean during Oceanic Anoxic Event 2
Probing anisotropies of the Stochastic Gravitational Wave Background with LISA
We investigate the sensitivity of the Laser Interferometer Space Antenna (LISA) to the anisotropies of the Stochastic Gravitational Wave Background (SGWB). We first discuss the main astrophysical and cosmological sources of SGWB which are characterized by anisotropies in the GW energy density, and we build a Signal-to-Noise estimator to quantify the sensitivity of LISA to different multipoles. We then perform a Fisher matrix analysis of the prospects of detectability of anisotropic features with LISA for individual multipoles, focusing on a SGWB with a power-law frequency profile. We compute the noise angular spectrum taking into account the specific scan strategy of the LISA detector. We analyze the case of the kinematic dipole and quadrupole generated by Doppler boosting an isotropic SGWB. We find that β ΩGW ∼ 2 × 10-11 is required to observe a dipolar signal with LISA. The detector response to the quadrupole has a factor ∼ 103 β relative to that of the dipole. The characterization of the anisotropies, both from a theoretical perspective and from a map-making point of view, allows us to extract information that can be used to understand the origin of the SGWB, and to discriminate among distinct superimposed SGWB sources
The Role of Bile in the Regulation of Exocrine Pancreatic Secretion
As early as 1926 Mellanby (1) was able to show that introduction of bile into the duodenum of anesthetized cats produces a copious flow of pancreatic juice. In conscious dogs, Ivy & Lueth (2) reported, bile is only a weak stimulant of pancreatic secretion. Diversion of bile from the duodenum, however, did not influence pancreatic volume secretion stimulated by a meal (3,4). Moreover, Thomas & Crider (5) observed that bile not only failed to stimulate the secretion of pancreatic juice but also abolished the pancreatic response to intraduodenally administered peptone or soap
Study of Kosterlitz-Thouless transition of Bose systems governed by a random potential using quantum Monte Carlo simulations
We perform quantum Monte Carlo simulations to study the 2D hard-core
Bose-Hubbard model in a random potential. Our motivation is to investigate the
effects of randomness on the Kosterlitz--Thouless (KT) transition. The chemical
potential is assumed to be random, by site, with a Gaussian distribution. The
KT transition is confirmed by a finite-size analysis of the superfluid density
and the power-law decay of the correlation function. By varying the variance of
the Gaussian distribution, we find that the transition temperature decreases as
the variance increases. We obtain the phase diagram showing the superfluid and
disordered phases, and estimate the quantum critical point (QCP). Our results
on the ground state reveal the existence of the Bose glass phase. Finally, we
discuss what the value of the variance at the QCP indicates from the viewpoint
of percolation.Comment: 7 pages, 9 figures, accepted for publication in JPS
Analysis of alternative splicing of cassette exons at single-cell level using two fluorescent proteins
Alternative splicing plays a major role in increasing proteome complexity and regulating gene expression. Here, we developed a new fluorescent protein-based approach to quantitatively analyze the alternative splicing of a target cassette exon (skipping or inclusion), which results in an open-reading frame shift. A fragment of a gene of interest is cloned between red and green fluorescent protein (RFP and GFP)-encoding sequences in such a way that translation of the normally spliced full-length transcript results in expression of both RFP and GFP. In contrast, alternative exon skipping results in the synthesis of RFP only. Green and red fluorescence intensities can be used to estimate the proportions of normal and alternative transcripts in each cell. The new method was successfully tested for human PIG3 (p53-inducible gene 3) cassette exon 4. Expected pattern of alternative splicing of PIG3 minigene was observed, including previously characterized effects of UV light irradiation and specific mutations. Interestingly, we observed a broad distribution of normal to alternative transcript ratio in individual cells with at least two distinct populations with ∼45% and >95% alternative transcript. We believe that this method is useful for fluorescence-based quantitative analysis of alternative splicing of target genes in a variety of biological models
Co-regulation of alternative splicing by diverse splicing factors in Caenorhabditis elegans
Regulation of alternative splicing is controlled by pre-mRNA sequences (cis-elements) and trans-acting protein factors that bind them. The combinatorial interactions of multiple protein factors with the cis-elements surrounding a given alternative splicing event lead to an integrated splicing decision. The mechanism of multifactorial splicing regulation is poorly understood. Using a splicing-sensitive DNA microarray, we assayed 352 Caenorhabditis elegans alternative cassette exons for changes in embryonic splicing patterns between wild-type and 12 different strains carrying mutations in a splicing factor. We identified many alternative splicing events that are regulated by multiple splicing factors. Many splicing factors have the ability to behave as splicing repressors for some alternative cassette exons and as splicing activators for others. Unexpectedly, we found that the ability of a given alternative splicing factor to behave as an enhancer or repressor of a specific splicing event can change during development. Our observations that splicing factors can change their effects on a substrate during development support a model in which combinatorial effects of multiple factors, both constitutive and developmentally regulated ones, contribute to the overall splicing decision
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