Origins of Inert Higgs Doublets

We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated $Z_2$ symmetry can occur automatically. Several examples are discussed.Comment: 14 pages, 1 table, no figure. References adde

An A_5 Model of Four Lepton Generations

We study the lepton sector of a four generations model based on the discrete flavor group $A_5$ (the even permutation of five objects). The best features of the three family $A_4$ model survive, including the tribimaximal pattern of three generation neutrino mixings. At leading order the three light neutrino mass relations of $m_{\nu_1} = m_{\nu_3}$ and $m_{\nu_2} = 0$ are predicted. The splitting of the neutrino masses can be naturally obtained as a result of the breaking of $A_{5}$ down to $A_4$ and a degenerate spectrum is preferred in our model. In our $A_5$ model, the electron mass is zero at tree level, but calculable through quantum corrections.Comment: 20 pages, 3 figures, and 3 tables; references and Appendix C added, version accepted for publication in JHE

Evaluating the Interest-Rate Risk of Adjustable-Rate Mortgage Loans

This paper evaluates the interest-rate risk inherent in an adjustable-rate mortgage (ARM) with sporadic rate adjustments and possibly binding periodic and life-of-loan rate change constraints. Simulation analysis forecasts ARM cash flows, determines the probability that constraints will hold, and partitions the loan into fixed and variable components. Simulation parameters are then altered to measure the impact of changes in contract terms and market conditions on the interest-rate risk of a typical ARM loan. Interest-rate sensitivity is found to be significantly less than that of fixed-rate loans and remarkably insensitive to changes in loan margins or initial loan rates after the first few years of an ARM's life. Therefore, it is not surprising that lenders have used these features to lure borrowers to ARMs. Periodic rate change limits and volatility in the underlying index are the only factors that influence the interest-rate risk of an existing ARM in a substantive way.

Phase Distribution and Phase Correlation of Financial Time Series

Scaling, phase distribution and phase correlation of financial time series are investigated based on the Dow Jones Industry Average (DJIA) and NASDAQ 10-minute intraday data for a period from Aug. 1 1997 to Dec. 31 2003. The returns of the two indices are shown to have nice scaling behaviors and belong to stable distributions according to the criterion of Levy's alpha stable distribution condition. A novel approach catching characteristic features of financial time series based on the concept of instantaneous phase is further proposed to study phase distribution and correlation. The analysis of phase distribution concludes return time series fall into a class which is different from other non-stationary time series. The correlation between returns of the two indices probed by the distribution of phase difference indicates there was a remarkable change of trading activities after the event of 911 attack, and this change persisted in later trading activities.Phase Distribution, High Frequency Data, Scaling Analysis, Levy Distribution, Stock Market, Frequency Variant

G2G_2 generating technique for minimal D=5 supergravity and black rings

A solution generating technique is developed for D=5 minimal supergravity with two commuting Killing vectors based on the $G_2$ U-duality arising in the reduction of the theory to three dimensions. The target space of the corresponding 3-dimensional sigma-model is the coset $G_{2(2)}/(SL(2,R)\times SL(2,R))$. Its isometries constitute the set of solution generating symmetries. These include two electric and two magnetic Harrison transformations with the corresponding two pairs of gauge transformations, three $SL(2,R) S$-duality transformations, and the three gravitational scale, gauge and Ehlers transformations (altogether 14). We construct a representation of the coset in terms of $7\times 7$ matrices realizing the automorphisms of split octonions. Generating a new solution amounts to transforming the coset matrices by one-parametric subgroups of $G_{2(2)}$ and subsequently solving the dualization equations. Using this formalism we derive a new charged black ring solution with two independent parameters of rotation.Comment: 21 pages revtex-4, 1 figure, typo corrected in Eq. (103

Stoichiometry and Change of the mRNA Closed-Loop Factors as Translating Ribosomes Transit from Initiation to Elongation

Protein synthesis is a highly efficient process and is under exacting control. Yet, the actual abundance of translation factors present in translating complexes and how these abundances change during the transit of a ribosome across an mRNA remains unknown. Using analytical ultracentrifugation with fluorescent detection we have determined the stoichiometry of the closed-loop translation factors for translating ribosomes. A variety of pools of translating polysomes and monosomes were identified, each containing different abundances of the closed-loop factors eIF4E, eIF4G, and PAB1 and that of the translational repressor, SBP1. We establish that closed-loop factors eIF4E/eIF4G dissociated both as ribosomes transited polyadenylated mRNA from initiation to elongation and as translation changed from the polysomal to monosomal state prior to cessation of translation. eIF4G was found to particularly dissociate from polyadenylated mRNA as polysomes moved to the monosomal state, suggesting an active role for translational repressors in this process. Consistent with this suggestion, translating complexes generally did not simultaneously contain eIF4E/eIF4G and SBP1, implying mutual exclusivity in such complexes. For substantially deadenylated mRNA, however, a second type of closed-loop structure was identified that contained just eIF4E and eIF4G. More than one eIF4G molecule per polysome appeared to be present in these complexes, supporting the importance of eIF4G interactions with the mRNA independent of PAB1. These latter closed-loop structures, which were particularly stable in polysomes, may be playing specific roles in both normal and disease states for specific mRNA that are deadenylated and/or lacking PAB1. These analyses establish a dynamic snapshot of molecular abundance changes during ribosomal transit across an mRNA in what are likely to be critical targets of regulation

Effects of formal mentoring support on newcomer-protégé affective organizational commitment:a self-concept-based perspective

The study proposes and tests a self-concept-based perspective for the effects of formal mentoring support on affective organizational commitment (AOC) via multiple mediators. Using time-lagged multi-source dyadic data (n = 203), we demonstrate that formal mentoring support significantly influences newcomer-proteges' AOC through an underlying self-evaluative mechanism indicated by organization-based self-esteem (OBSE), even in the presence of a well-established alternative mediator (perceived organizational support; POS). Moreover, we further demonstrate when or under what circumstances such effects might be attenuated or exaggerated by introducing a salient boundary condition to such a process (i.e., perceived mentor organizational prototypicality). As the findings reveal, by making newcomer-proteges feel good about themselves in the workplace (i.e., perceive self-value) formal mentoring support can also promote organizational commitment, effects that are likely to be amplified when the formal mentor is perceived to be prototypical of the organization. Thus, bridging the mentoring and socialization literatures, the inclusion of our proposed mediators and moderator and testing their relationships simultaneously not only provides a more nuanced view of the underlying mechanisms through which the effects of formal mentoring support are channeled to influence newcomer-proteges' work attitudes but it offers new theoretical elaboration and contextual understanding that we hope will prompt future research and be of benefit to human resource practitioners. Implications to theory, practice and future research directions are discussed

Long-Run Underperformance And The Offering Price Clustering Phenomenon

The study proposes a new informational role for the offering price of an equity IPO.  Offering prices are quoted either in whole prices (e.g., $2,$11, $19, etc) or fractional prices (e.g.,$2.35, $11.15,$15.75, etc).  Using Jay R. Ritter’s sample of 1,526 IPOs issued during the period 1975 to 1984, the study examines the relation between the presence of whole price clusters and long-run underperformance.  The results indicate that fractional offering prices are associated with better long-run performance. &nbsp

Hadron structure at small momentum transfer

Giving three examples, the form factors of the nucleon, the polarisability of the charged pion and the interference of the $S_{11}(1535)$ with the $D_{13}(1520)$ excitation of the nucleon in the $\eta p$-decay channel, it is argued that the hadron structure at low momentum transfer is highly significant for studying QCD.Comment: 7 pages, 9 figures. Contribution to the International School of Nuclear Physics, 29th Ccourse, "Quarks in Hadrons and Nuclei", Erice, Sicily, 16 - 24 September 200

Investor Sentiment And Close-End Country Funds?

An innovative method to estimate the duration of investor sentiment is applied to closed-end country fund returns and it finds that U.S. investor sentiment has a short life.  The effects of sentiment on closed-end country fund returns are largely consistent with existing literature however, it is only apparent in daily time-series regressions.  Sentiment rapidly fades at a weekly frequency and virtually disappears using monthly return observations.  These results suggest that the kind of investor sentiment for country fund prices does not have a persistent component