2,394 research outputs found
Non-axisymmetric baby-skyrmion branes
We investigate the existence of non axisymmetric solutions in the
6-dimensional baby-Skyrme brane model. The brane is described by a localized
solution to the baby-Skyrme model extending in the extra dimensions. Such non
symmetric branes have already been constructed in the original 2+1-dimensional
baby-Skyrme model in flat space. We generalize this result to the case of
gravitating baby-Skyrme and in the context of extradimensions. These
non-trivial deformation from the axisymmetric shape appear for higher values of
the topological charge, so we consider the cases of , where is the
topological charge. We solve the coupled system of the Einstein and baby-Skyrme
equations by successive over relaxation method. We argue that the result may be
a possible resolution for the fermion mass hierarchy puzzle.Comment: 14 pages, 14 figure
Deterministic cavity quantum electrodynamics with trapped ions
We have employed radio-frequency trapping to localize a single 40Ca+-ion in a high-finesse optical cavity. By means of laser Doppler cooling, the position spread of the ion's wavefunction along the cavity axis was reduced to 42 nm, a fraction of the resonance wavelength of ionized calcium (λ = 397 nm). By controlling the position of the ion in the optical field, continuous and completely deterministic coupling of ion and field was realized. The precise three-dimensional location of the ion in the cavity was measured by observing the fluorescent light emitted upon excitation in the cavity field. The single-ion system is ideally suited to implement cavity quantum electrodynamics under cw conditions. To this end we operate the cavity on the D3/2–P1/2 transition of 40Ca+ (λ = 866 nm). Applications include the controlled generation of single-photon pulses with high efficiency and two-ion quantum gates
Investigation of the crystallization process of CSD-ErBCO on IBAD-substrate via DSD approach
REBaCuO (REBCO, RE: rare earth, such as Y and Gd) compounds have been extensively studied as a superconducting layer in coated conductors. Although ErBCO potentially has better superconducting properties than YBCO and GdBCO, little research has been made on it, especially in chemical solution deposition (CSD). In this work, ErBCO films were deposited on IBAD (ion-beam-assisted-deposition) substrates by CSD with low-fluorine solutions. The crystallization process was optimized to achieve the highest self-field critical current density (J) at 77 K. Commonly, for the investigation of a CSD process involving numerous process factors, one factor is changed keeping the others constant, requiring much time and cost. For more efficient investigation, this study adopted a novel design-of-experiment technique, definitive screening design (DSD), for the first time in CSD process. Two different types of solutions containing Er-propionate or Er-acetate were used to make two types of samples, Er-P and Er-A, respectively. Within the investigated range, we found that crystallization temperature, dew point, and oxygen partial pressure play a key role in Er-P, while the former two factors are significant for Er-A. DSD revealed these significant factors among six process factors with only 14 trials. Moreover, the DSD approach allowed us to create models that predict J accurately. These models revealed the optimum conditions giving the highest J values of 3.6 MA/cm for Er-P and 3.0 MA/cm for Er-A. These results indicate that DSD is an attractive approach to optimize CSD process
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
Exponential Random Graph Modeling for Complex Brain Networks
Exponential random graph models (ERGMs), also known as p* models, have been
utilized extensively in the social science literature to study complex networks
and how their global structure depends on underlying structural components.
However, the literature on their use in biological networks (especially brain
networks) has remained sparse. Descriptive models based on a specific feature
of the graph (clustering coefficient, degree distribution, etc.) have dominated
connectivity research in neuroscience. Corresponding generative models have
been developed to reproduce one of these features. However, the complexity
inherent in whole-brain network data necessitates the development and use of
tools that allow the systematic exploration of several features simultaneously
and how they interact to form the global network architecture. ERGMs provide a
statistically principled approach to the assessment of how a set of interacting
local brain network features gives rise to the global structure. We illustrate
the utility of ERGMs for modeling, analyzing, and simulating complex
whole-brain networks with network data from normal subjects. We also provide a
foundation for the selection of important local features through the
implementation and assessment of three selection approaches: a traditional
p-value based backward selection approach, an information criterion approach
(AIC), and a graphical goodness of fit (GOF) approach. The graphical GOF
approach serves as the best method given the scientific interest in being able
to capture and reproduce the structure of fitted brain networks
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
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
Enhancing lepton flavour violation in the supersymmetric inverse seesaw beyond the dipole contribution
In minimal supersymmetric models the -penguin usually provides
sub-dominant contributions to charged lepton flavour violating observables. In
this study, we consider the supersymmetric inverse seesaw in which the
non-minimal particle content allows for dominant contributions of the
-penguin to several lepton flavour violating observables. In particular, and
due to the low-scale (TeV) seesaw, the penguin contribution to, for instance,
\Br(\mu \to 3e) and conversion in nuclei, allows to render some of
these observables within future sensitivity reach. Moreover, we show that in
this framework, the -penguin exhibits the same non-decoupling behaviour
which had previously been identified in flavour violating Higgs decays in the
Minimal Supersymmetric Standard Model.Comment: 29 pages, 9 figures, 4 tables; v2: minor corrections, version to
appear in JHE
- …