1,450 research outputs found
New Solution for Neutrino Masses and Leptogenesis in Adjoint SU(5)
We investigate baryogenesis via leptogenesis and generation of neutrino
masses and mixings through the Type I plus Type III seesaw plus an one-loop
mechanism in the context of Renormalizable Adjoint SU(5) theory. One light
neutrino remains massless, because the contributions of three heavy Majorana
fermions \rho_0, \rho_3 and \rho_8 to the neutrino mass matrix are not linearly
independent. However none of these heavy fermions is decoupled from the
generation of neutrino masses. This opens a new range in parameter space for
successful leptogenesis, in particular, allows for inverted hierarchy of the
neutrino masses.Comment: 16 pages, 4 figures; references added and typos fixe
Absolutely stable proton and lowering the gauge unification scale
A unified model is constructed, based on flipped SU(5) in which the proton is absolutely stable. The model requires the existence of new leptons with masses of order the weak scale. The possibility that the unification scale could be extremely low is discussed
Seesaw Neutrino Signals at the Large Hadron Collider
We discuss the scenario with gauge singlet fermions (right-handed neutrinos)
accessible at the energy of the Large Hadron Collider. The singlet fermions
generate tiny neutrino masses via the seesaw mechanism and also have sizable
couplings to the standard-model particles. We demonstrate that these two facts,
which are naively not satisfied simultaneously, are reconciled in the
five-dimensional framework in various fashions, which make the seesaw mechanism
observable. The collider signal of tri-lepton final states with transverse
missing energy is investigated for two explicit examples of the observable
seesaw, taking account of three types of neutrino mass spectrum and the
constraint from lepton flavor violation. We find by showing the significance of
signal discovery that the collider experiment has a potential to find signals
of extra dimensions and the origin of small neutrino masses.Comment: 27 pages, 4 figure
Learning While Black: A Qualitative Analysis of the Impact of Race in a U.S. High School
One of the major contributing factors to the Black-White achievement gap is school context. While many factors can affect academic achievement amongst Black youth, school climate and inter-racial relations are among the root causes which impact Black students’ development. In this qualitative study, we conducted secondary analysis of existing data consisting of interview transcripts and focus group discussions held in 2013 with 21 Black students who attended a public charter high school in Michigan. Open access data were downloaded from the University of Michigan Inter-University Consortium for Political and Social Research (ICPSR) database. We analyzed qualitative data for themes and constructs related to school context and such influences on Black youth development. The following three constructs were identified: racial identity of Black youth, the impact of teachers on Black students’ racial identity and development, and lastly, exploring the dominant culture of the U.S. education system. For researchers, this data highlights a need for more studies on the intersection of race, school environment, and youth development. For administrators and policy makers, the results emphasize the need for investment and engagement in the daily experiences of Black students, reducing racism, and increasing diversity of curriculum. Teachers and school administrators may benefit from specialized training to better address cultural, educational, and developmental needs of Black youth in the context of their role in school
THG113.31, a specific PGF2alpha receptor antagonist, induces human myometrial relaxation and BKCa channel activation
BACKGROUND: PGF2alpha exerts a significant contractile effect on myometrium and is central to human labour. THG113.31, a specific non-competitive PGF2alpha receptor (FP) antagonist, exerts an inhibitory effect on myometrial contractility. The BKCa channel is ubiquitously encountered in human uterine tissue and plays a significant role in modulating myometrial cell membrane potential and excitability. The objective of this study was to investigate potential BKCa channel involvement in the response of human myometrium to THG113.31. METHODS: Single and whole-cell electrophysiological BKCa channel recordings from freshly dispersed myocytes, were investigated in the presence and absence of THG113.31. Functional studies investigated the effects of THG113.31 on isolated spontaneous myometrial contractions, in the presence and absence of the BKCa channel blocker, iberiotoxin. RESULTS: Single channel recordings identified the BKCa channel as a target of THG113.31. THG113.31 significantly increased the open state probability of these channels [control 0.023+/-0.006; 10 microM THG113.31 0.087+/-0.012 (P = 0.009); and 50 microM THG113.31 0.1356+/-0.018 (P = 0.001)]. In addition, THG113.31 increased whole-cell BKCa currents over a range of membrane potentials, and this effect was reversed by 100 nanoM IbTX. Isometric tension studies demonstrated that THG113.31 exerted a significant concentration-dependent relaxant effect on human myometrial tissue and pre-incubation of strips with IbTX abolished this effect on spontaneously occurring contractions. CONCLUSION: These data suggests that activation of the BKCa channel may contribute, at least partially, to the uterorelaxant effect of THG113.31
A Collective Breaking of R-Parity
Supersymmetric theories with an R-parity generally yield a striking missing
energy signature, with cascade decays concluding in a neutralino that escapes
the detector. In theories where R-parity is broken the missing energy is
replaced with additional jets or leptons, often making traditional search
strategies ineffective. Such R-parity violation is very constrained, however,
by resulting B and L violating signals, requiring couplings so small that LSPs
will decay outside the detector in all but a few scenarios. In theories with
additional matter fields, R-parity can be broken collectively, such that
R-parity is not broken by any single coupling, but only by an ensemble of
couplings. Cascade decays can proceed normally, with each step only sensitive
to one or two couplings at a time, but B and L violation requires the full set,
yielding a highly suppressed constraint. s-channel production of new scalar
states, typically small for standard RPV, can be large when RPV is broken
collectively. While missing energy is absent, making these models difficult to
discover by traditional SUSY searches, they produce complicated many object
resonances (MORes), with many different possible numbers of jets and leptons.
We outline a simple model and discuss its discoverability at the LHC.Comment: 28 pages, 10 figure
Colored Resonant Signals at the LHC: Largest Rate and Simplest Topology
We study the colored resonance production at the LHC in a most general
approach. We classify the possible colored resonances based on group theory
decomposition, and construct their effective interactions with light partons.
The production cross section from annihilation of valence quarks or gluons may
be on the order of 400 - 1000 pb at LHC energies for a mass of 1 TeV with
nominal couplings, leading to the largest production rates for new physics at
the TeV scale, and simplest event topology with dijet final states. We apply
the new dijet data from the LHC experiments to put bounds on various possible
colored resonant states. The current bounds range from 0.9 to 2.7 TeV. The
formulation is readily applicable for future searches including other decay
modes.Comment: 29 pages, 9 figures. References updated and additional K-factors
include
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