3,794 research outputs found
Research Notes : Studies in polyploidy in soybeans: A simple and effective colchicine technique of chromosome doubling for soybean (Glycine max (L .) Merr.) and its wild relatives.
Tang and Loo (1940) first reported the induction of tetraploid soybeans by soaking day-old seedlings in 0.05 to 0.1% colchicine solution for 24 or 48 h. Oinuma (1952) obtained tetraploids by soaking dry soybean seeds in 0.1% colchicine solution for 24, 48 and 72 h. His results showed that the survival of resulting plants was poor
A Novel Solution to the Gravitino Problem
In a general phenomenological model with local supersymmetry, the amount of
massive gravitinos produced in early universe tends to violate the known dark
matter density bound by many orders of magnitude. This problem is absent in the
recently proposed non-linear supergravity model in the brane world scenario in
Type IIB string theory, where we (i.e., the standard model of strong and
electroweak interactions) live in a stack of -branes (i.e.,
anti-D3-branes) that span the 3 large spatial dimensions. These -branes break supersymmetry. As an open string mode in there, the Goldstino
to be eaten by the gravitino is present only inside the -branes. So, although a gravitino can be massive (e.g., GeV) inside the -branes, it is (almost) massless
outside the -branes. It follows that the massive gravitinos
produced inside the -branes will be pushed out of the
-branes, analogous to the Meissner effect for the massive
photons in super-conductors. As a result, the massive gravitinos will be
depleted so the gravitino problem is absent.Comment: 13 pages, 1 figure, 2 table
Baryon Number Violating Rate as A Function of the Proton-Proton Collision Energy
The baryon-number violation (BV) happens in the standard electroweak model.
According to the Bloch-wave picture, the BV event rate shall be significantly
enhanced when the proton-proton collision center of mass (COM) energy goes
beyond the sphaleron barrier height . Here we
compare the BV event rates at different COM energies, using the Bloch-wave band
structure and the CT18 parton distribution function data, with the phase space
suppression factor included. As an example, the BV cross-section at 25 TeV is 4
orders of magnitude bigger than its cross-section at 13 TeV.Comment: 7 pages, 6 figures, and 4 table
Chromosomal integration of an avian oncogenic herpesvirus reveals telomeric preferences and evidence for lymphoma clonality
Abstract Background Herpesviruses are a major health concern for numerous organisms, including humans, causing both acute and chronic infections recurrent over an individual's lifespan. Marek's disease virus (MDV) is a highly contagious herpesvirus which causes a neoplastic condition in chicken populations. Several vertebrate-infecting herpesviruses have been shown to exist in an integrated state during latent periods of infection. However the status of MDV during latency has been a topic of debate. Results Here we employed high-resolution multi-color fluorescence in situ hybridization (FISH) to show integration of MDV at the telomeres of chicken chromosomes. Cytogenomic mapping of the chromosomal integrations allowed us to examine the clonal relationships among lymphomas within individuals, whereas analysis of tumors from multiple individuals indicated the potential for chromosomal preferences. Conclusions Our data highlight that substantive genome-level interactions between the virus and host exist, and merit consideration for their potential impact and role in key aspects of herpesvirus pathobiology including infection, latency, cellular transformation, latency-breaks and viral evolution
The Hubble Constant in the Axi-Higgs Universe
The CDM model provides an excellent fit to the CMB data. However, a
statistically significant tension emerges when its determination of the Hubble
constant is compared to the local distance-redshift measurements. The
axi-Higgs model, which couples an ultralight axion to the Higgs field, offers a
specific variation of the CDM model. It relaxes the tension as
well as explains the Li puzzle in Big-Bang nucleosynthesis, the clustering
tension with the weak-lensing data, and the observed isotropic cosmic
birefringence in CMB. In this paper, we demonstrate how the and
tensions can be relaxed simultaneously, by correlating the axion impacts on the
early and late universe. In a benchmark scenario ( eV)
selected for experimental tests soon, the analysis combining the CMB+BAO+WL+SN
data yields km/s/Mpc and .
Combining this (excluding the SN (supernovae) part) with the local
distance-redshift measurements yields km/s/Mpc, while
is slightly more suppressed.Comment: 15 pages, 11 figures, final version published on PRR Lette
Menthol Alone Upregulates Midbrain nAChRs, Alters nAChR Subtype Stoichiometry, Alters Dopamine Neuron Firing Frequency, and Prevents Nicotine Reward
Upregulation of β2 subunit-containing (β2*) nicotinic acetylcholine receptors (nAChRs) is implicated in several aspects of nicotine addiction, and menthol cigarette smokers tend to upregulate β2* nAChRs more than nonmenthol cigarette smokers. We investigated the effect of long-term menthol alone on midbrain neurons containing nAChRs. In midbrain dopaminergic (DA) neurons from mice containing fluorescent nAChR subunits, menthol alone increased the number of α4 and α6 nAChR subunits, but this upregulation did not occur in midbrain GABAergic neurons. Thus, chronic menthol produces a cell-type-selective upregulation of α4* nAChRs, complementing that of chronic nicotine alone, which upregulates α4 subunit-containing (α4*) nAChRs in GABAergic but not DA neurons. In mouse brain slices and cultured midbrain neurons, menthol reduced DA neuron firing frequency and altered DA neuron excitability following nAChR activation. Furthermore, menthol exposure before nicotine abolished nicotine reward-related behavior in mice. In neuroblastoma cells transfected with fluorescent nAChR subunits, exposure to 500 nM menthol alone also increased nAChR number and favored the formation of (α4)_3(β2)_2 nAChRs; this contrasts with the action of nicotine itself, which favors (α4)_2(β2)_3 nAChRs. Menthol alone also increases the number of α6β2 receptors that exclude the β3 subunit. Thus, menthol stabilizes lower-sensitivity α4* and α6 subunit-containing nAChRs, possibly by acting as a chemical chaperone. The abolition of nicotine reward-related behavior may be mediated through menthol's ability to stabilize lower-sensitivity nAChRs and alter DA neuron excitability. We conclude that menthol is more than a tobacco flavorant: administered alone chronically, it alters midbrain DA neurons of the nicotine reward-related pathway
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