2,216 research outputs found
Radiative lepton flavor violating decays in the Randall Sundrum background with localized leptons
We study the radiative lepton flavor violating l_i -> l_j\gamma decays in the
two Higgs doublet model, respecting the Randall Sundrum scenario and estimate
the contributions of the KK modes of left (right) handed charged lepton
doublets (singlets) on the branching ratios. We observe that the branching
ratios are sensitive to the contributions of the charged lepton KK modes.Comment: 23 pages, 10 figures, 2 table
An Asian emission inventory of anthropogenic emission sources for the period 1980?2020
International audienceWe developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980?2020. REAS is the first inventory to integrate historical, present, and future emissions in Asia on the basis of a consistent methodology. We present here emissions in 2000, historical emissions for 1980?2003, and projected emissions for 2010 and 2020 of SO2, NOx, CO, NMVOC, black carbon (BC), and organic carbon (OC) from fuel combustion and industrial sources. Total energy consumption in Asia more than doubled between 1980 and 2003, causing a rapid growth in Asian emissions, by 28% for BC, 30% for OC, 64% for CO, 108% for NMVOC, 119% for SO2, and 176% for NOx. In particular, Chinese NOx emissions showed a marked increase of 280% over 1980 levels, and growth in emissions since 2000 has been extremely high. These increases in China were mainly caused by increases in coal combustion in the power plants and industrial sectors. NMVOC emissions also rapidly increased because of growth in the use of automobiles, solvents, and paints. By contrast, BC, OC, and CO emissions in China showed decreasing trends from 1996 to 2000 because of a reduction in the use of biofuels and coal in the domestic and industry sectors. However, since 2000, Chinese emissions of these species have begun to increase. Thus, the emissions of air pollutants in Asian countries (especially China) showed large temporal variations from 1980?2003. Future emissions in 2010 and 2020 in Asian countries were projected by emission scenarios and from emissions in 2000. For China, we developed three emission scenarios: PSC (policy success case), REF (reference case), and PFC (policy failure case). In the 2020 REF scenario, Asian total emissions of SO2, NOx, and NMVOC were projected to increase substantially by 22%, 44%, and 99%, respectively, over 2000 levels. The 2020 REF scenario showed a modest increase in CO (12%), a lesser increase in BC (1%), and a slight decrease in OC (?5%) compared with 2000 levels. However, it should be noted that Asian total emissions are strongly influenced by the emission scenarios for China
The radiative lepton flavor violating decays in the split fermion scenario in the two Higgs doublet model
We study the branching ratios of the lepton flavor violating processes \mu ->
e \gamma, \tau -> e \gamma and \tau -> \mu\gamma in the split fermion scenario,
in the framework of the two Higgs doublet model. We observe that the branching
ratios are relatively more sensitive to the compactification scale and the
Gaussian widths of the leptons in the extra dimensions, for two extra
dimensions and especially for the \tau -> \mu \gamma decay.Comment: 19 pages, 7 Figure
Imaging mass spectrometry detects dynamic changes of phosphatidylcholine in rat hippocampal CA1 after transient global ischemia
AbstractBackground and purpose: The initial steps in the cascade leading to cell death are still unknown because of the limitations of the existing methodology, strategy, and modalities used. Methods: Imaging mass spectrometry (IMS) was used to measure dynamic molecular changes of phosphatidylcholine (PC) species in the rat hippocampus after transient global ischemia (TGI) for 6min. Fresh frozen sections were obtained after euthanizing the rats on Days 1, 2, 4, 7, 10, 14, and 21. Histopathology and IMS of adjacent sections compared morphological and molecular changes, respectively. Results: Histopathological changes were absent immediately after TGI (at Day 1, superacute phase). At Days 2–21 after TGI (from subacute to chronic phases), histopathology revealed neuronal death associated with gliosis, inflammation, and accumulation of activated microglia in CA1. IMS detected significant molecular changes after TGI in the same CA1 domain: increase of PC (diacyl-16:0/22:6) in the superacute phase and increase of PC (diacyl-16:0/18:1) in the subacute to chronic phases. Conclusions: Histopathology and IMS can provide comprehensive and complementary information on cell death mechanisms in the hippocampal CA1 after global ischemia. IMS provided novel data on molecular changes in phospholipids immediately after TGI. Increased level of PC (diacyl-16:0/22:6) in the pyramidal cell layer of hippocampal CA1 prior to the histopathological change may represent an early step in delayed neuronal death mechanisms
Reductions of docosahexaenoic acid-containing phosphatidylcholine levels in the anterior horn of an ALS mouse model
AbstractIn this study, we analyzed the spatiotemporal alterations of phospholipid composition in the spinal cord of an amyotrophic lateral sclerosis (ALS) mouse model (G93A-mutated human superoxide dismutase 1 transgenic mice [SOD1G93A mice]) using imaging mass spectrometry (IMS), a powerful method to visualize spatial distributions of various types of molecules in situ. Using this technique, we deciphered the phospholipid distribution in the pre-symptomatic stage, early stage after disease onset, and terminal stages of disease in female SOD1G93A mouse spinal cords. These experiments revealed a significant decrease in levels of docosahexaenoic acid (DHA)-containing phosphatidylcholines (PCs), such as PC (diacyl-16:0/22:6), PC (diacyl-18:0/22:6), and PC (diacyl-18:1/22:6) in the L5 anterior horns of terminal stage (22-week-old) SOD1G93A mice. The reduction in PC (diacyl-16:0/22:6) level could be reflecting the loss of motor neurons themselves in the anterior horn of the spinal cord in ALS model mice. In contrast, other PCs, such as PC (diacyl-16:0/16:0), were observed specifically in the L5 dorsal horn gray matter, and their levels did not vary between ALS model mice and controls. Thus, our study showed a significant decrease in DHA-containing PCs, but not other PCs, in the terminal stage of ALS in model mice, which is likely to be a reflection of neuronal loss in the anterior horns of the spinal cords. Given its enrichment in dorsal sensory regions, the preservation of PC (diacyl-16:0/16:0) may be the result of spinal sensory neurons being unaffected in ALS. Taken together, these findings suggest that ALS spinal cords show significant alterations in PC metabolism only at the terminal stage of the disease, and that these changes are confined to specific anatomical regions and cell types
LHC sensitivity to lepton flavour violating Z boson decays
We estimate that the LHC could set bounds BR(Z -> mu^\pm e^\mp) < 4.1 *
10^{-7} and BR(Z -> tau^\pm mu^\mp)< 3.5 * 10^{-6} (at 95% C.L.) with 20
inverse fb of data at 8 TeV. A similar sensitivity can be anticipated for Z ->
tau^\pm e^\mp, because we consider leptonic tau decays such that Z -> tau^+
mu^- gives e^+ \mu^- +$ invisibles. These limits can be compared to the LEP1
bounds of order 10^{-5} to 10^{-6}. Such collider searches are sensitive to a
flavour-changing effective Z coupling which is energy dependent, so are
complementary to bounds obtained from tau to 3mu and mu to 3e.Comment: 11 pages, 2 figures, version for publicatio
A Single Amino Acid Substitution in the NS2A Protein of Japanese Encephalitis Virus Affects Virus Propagation In Vitro but Not In Vivo
We identified a unique amino acid of NS2A113, phenylalanine, that affects the efficient propagation of two Japanese encephalitis virus strains, JaTH160 and JaOArS982, in neuroblastoma Neuro-2a cells but not in cell lines of extraneural origin. This amino acid did not affect viral loads in the brain or survival curves in mice. These findings suggest that virus propagation in vitro may not reflect the level of virus neuroinvasiveness in vivo
TeV-scale seesaw from a multi-Higgs model
We suggest new simple model of generating tiny neutrino masses through a
TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model
is a simple extension of the standard model by introducing extra one Higgs
singlet, and one Higgs doublet with a tiny vacuum expectation value.
Experimental constraints, electroweak precision data and no large flavor
changing neutral currents, are satisfied since the extra doublet only has a
Yukawa interaction with lepton doublets and right-handed neutrinos, and their
masses are heavy of order a TeV-scale. Since active light neutrinos are
Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure
Testing new physics with the electron g-2
We argue that the anomalous magnetic moment of the electron (a_e) can be used
to probe new physics. We show that the present bound on new-physics
contributions to a_e is 8*10^-13, but the sensitivity can be improved by about
an order of magnitude with new measurements of a_e and more refined
determinations of alpha in atomic-physics experiments. Tests on new-physics
effects in a_e can play a crucial role in the interpretation of the observed
discrepancy in the anomalous magnetic moment of the muon (a_mu). In a large
class of models, new contributions to magnetic moments scale with the square of
lepton masses and thus the anomaly in a_mu suggests a new-physics effect in a_e
of (0.7 +- 0.2)*10^-13. We also present examples of new-physics theories in
which this scaling is violated and larger effects in a_e are expected. In such
models the value of a_e is correlated with specific predictions for processes
with violation of lepton number or lepton universality, and with the electric
dipole moment of the electron.Comment: 34 pages, 7 figures. Minor changes and references adde
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