Stereospecific Synthesis of 2,3-Dimethoxynaphtho[1,2-b] indolizidine

(11aS)- and (11aR)-2,3-dimethoxy-naphtho[1,2-b]indolizidine (9a and 9b) were synthesized from optically pure L- and D-glutamic acid through several steps (scheme 1). All the intermediates of the route to the optical antipodes of 9 exhibit identical physical and spectral properties except the sign of the optical rotation values. The optical purity of the enantiomers of 6 was checked by 1H-NMR spectra using Eu(tfc)3, that of the enantiomers of 9 by HPLC-separation on a chiral column; the amount of racemization was less than 3% in 9a and 9b, respectively. Die (11aS)- und (11aR)-2,3-Dimethoxy-naphtho[1,2-b]indolizidine (9a) und (9b) wurden, ausgehend von optisch reiner L- bzw. D-Glutaminsäure, synthetisiert (Schema 1). Alle Zwischenprodukte auf dem Weg zu 9 zeigen identische physikalische und spektrale Eigenschaften mit Ausnahme des Drehsinns. Die optische Reinheit der 6-Enantiomere wurde durch 1H-NMRSpektroskopie mit Eu(tfc)3 bestimmt, die der 9-Enantiomere durch HPLCTrennung auf einer chiralen Säule: die Razemisierungsrate war in 9a und 9b <3%

A radiative model with a naturally mild neutrino mass hierarchy

Many neutrino mass models postulate the existence of at least two extra fermions in order to account for the measured solar and atmospheric mass splittings. In these models, however, the predicted hierarchy between the two mass splittings is generically much larger than the observed one, unless extra flavor symmetries are introduced. We present in this letter a radiative neutrino mass model consisting of the Standard Model extended by one heavy fermionic singlet and two scalars which predicts, under very general conditions, a neutrino mass hierarchy in qualitative agreement with the experimental value.Comment: 8 pages, 2 figure

Fluctuation-induced Topological Quantum Phase Transitions in Quantum Spin Hall and Quantum Anomalous Hall Insulators

We investigate the role of quantum fluctuations in topological quantum phase transitions of quantum spin Hall insulators and quantum anomalous Hall insulators. Employing the variational cluster approximation to obtain the single-particle Green's function of the interacting many-body system, we characterize different phases by direct calculation of the recently proposed topological order parameter for interacting systems. We pinpoint the influence of quantum fluctuations on the quantum spin Hall to Mott insulator transition in several models. Furthermore, we propose a general mechanism by which a topological quantum phase transition can be driven by the divergence of the self energy induced by interactions

Classification of Effective Neutrino Mass Operators

We present a classification of SU(3) x SU(2) x U(1) gauge invariant \Delta L = 2 (L being lepton number) effective operators relevant for generating small Majorana neutrino masses. Operators of dimension up to 11 have been included in our analysis. This approach enables us to systematically identify interesting neutrino mass models. It is shown that many of the well-known models fall into this classification. In addition, a number of new models are proposed and their neutrino phenomenology is outlined. Of particular interest is a large class of models in which neutrinoless double beta decays arise at a lower order compared to the neutrino mass, making these decays accessible to the current round of experiments.Comment: 34 pages in RevTeX with 18 figure

The solar LMA neutrino oscillation solution in the Zee model

We examine the neutrino mass matrix in the version of Zee model where both Higgs doublets couple to the leptons. We show that in this case one can accommodate the large mixing angle (LMA) MSW solution of the solar neutrino problem, while avoiding maximal solar mixing and conflicts with constraints on lepton family number-violating interactions. In the simplified scenario we consider, we have the neutrino mass spectrum characterized by $m_1 \simeq m_2 \simeq \sqrt{\Delta m^2_\mathrm{atm}}/\sin 2\theta$ and $m_3/m_1 \simeq \cos 2\theta$, where $\theta$ is the solar mixing angle.Comment: 13 pages, LaTeX, no figures; misprints in Eq. (39) correcte

Non-standard neutrino interactions in the Zee-Babu model

We investigate non-standard neutrino interactions (NSIs) in the Zee--Babu model. The size of NSIs predicted by this model is obtained from a full scan over the parameter space, taking into account constraints from low-energy experiments such as searches for lepton flavor violation (LFV) and the requirement to obtain a viable neutrino mass matrix. The dependence on the scale of new physics as well as on the type of the neutrino mass hierarchy is discussed. We find that NSIs at the source of a future neutrino factory may be at an observable level in the nu_e to nu_tau and/or nu_mu to nu_tau channels. In particular, if the doubly charged scalar of the model has a mass in reach of the LHC and if the neutrino mass hierarchy is inverted, a highly predictive scenario is obtained with observable signals at the LHC, in upcoming neutrino oscillation experiments, in LFV processes, and for NSIs at a neutrino factory.Comment: 9 pages, 4 figure

Adherence to pediatric diabetic ketoacidosis guidelines by community emergency departments' providers

Background: Diabetic ketoacidosis (DKA) is a common presentation of type I diabetes mellitus to the emergency departments. Most children with DKA are initially managed in community emergency departments where providers may not have easy access to educational resources or pediatric-specific guidelines and protocols that are readily available at pediatric academic medical centers. The aim of this study is to evaluate adherence of community emergency departments in the state of Indiana to the pediatric DKA guidelines. Methods: We performed a retrospective chart review of patients, age 18 years of age or under, admitted to the pediatric intensive care unit with a diagnosis of DKA. Results: A total of 100 patients were included in the analysis. Thirty-seven percent of patients with DKA were managed according to all six guideline parameters. Only 39% of patients received the recommended hourly blood glucose checks. Thirty percent of patients received intravenous insulin bolus, which is not recommended. Conclusions: Non-adherence to pediatric DKA guidelines still exists in the state of Indiana. Further, larger studies are needed to reveal the etiology of non-adherence to pediatric DKA guidelines and strategies to improve that adherence

Non-decoupling effects in supersymmetric Higgs sectors

A wide class of Higgs sectors is investigated in supersymmetric standard models. When the lightest Higgs boson (h) looks the standard model one, the mass (m_h) and the triple Higgs boson coupling (the hhh coupling) are evaluated at the one-loop level in each model. While m_h is at most 120-130 GeV in the minimal supersymmetric standard model (MSSM), that in models with an additional neutral singlet or triplet fields can be much larger. The hhh coupling can also be sensitive to the models: while in the MSSM the deviation from the standard model prediction is not significant, that can be 30-60 % in some models such as the MSSM with the additional singlet or with extra doublets and charged singlets. These models are motivated by specific physics problems like the mu-problem, the neutrino mass, the scalar dark matter and so on. Therefore, when h is found at the CERN Large Hadron Collider, we can classify supersymmetric models by measuring m_h and the hhh coupling accurately at future collider experiments.Comment: 16pages, 6figures. To be published in Physics Letters

Neutrino Masses, Dark Matter and B-L Symmetry at the LHC

We establish a hybrid seesaw mechanism to explain small neutrino masses and predict cold dark matter candidate in the context of the B-L gauge symmetry extension of the Standard Model. In this model a new scalar doublet and two new fermion singlets are introduced at loop-level beyond the minimal Type I seesaw. The lightest particle inside the loop can be dark matter candidate. We study in detail the constraints from neutrino oscillation data, lepton flavor violating processes and cosmological observation. We also explore the predictions of the decays of the new charged scalars in each spectrum of neutrino masses and show the most optimistic scenarios to distinguish the spectra. We consider the pair production of the stable fermion associated with two observable SM charged leptons at the LHC, which occurs in a two-step cascade decay of the new gauge boson Z' and the new charged scalars stand as intermediate particles. The masses of missing dark matter and its parent particle can be well-determined in such production topology.Comment: 20 pages, 9 figures and 2 tables, revised version accepted for publication in Nucl. Phys.

Pure Leptonic Gauge Symmetry, Neutrino Masses and Dark Matter

A possible extension of the Standard Model to include lepton number as local gauge symmetry is investigated. In such a model, anomalies are canceled by two extra fermions doublet. After leptonic gauge symmetry spontaneously broken, three active neutrinos may acquire non-zero Majorana masses through the modified Type-II seesaw mechanism. Constraints on the model from electro-weak precision measurements are studied. Due to the $Z_2$ discrete flavor symmetry, right-handed Majorana neutrinos can serve as cold dark matter candidate of the Universe. Constraint from dark matter relic abundance is calculated.Comment: 13 pages, 2 figures; typos corrected, comments and references added, to appear in Phys. Lett.