On neutrino and charged lepton masses and mixings: A view from the electroweak-scale right-handed neutrino model

We present a model of neutrino masses within the framework of the EW-$\nu_R$ model in which the experimentally desired form of the PMNS matrix is obtained by applying an $A_4$ symmetry to the \emph{Higgs singlet sector} responsible for the neutrino Dirac mass matrix. This mechanism naturally avoids potential conflict with the LHC data which severely constrains the Higgs sector, in particular the Higgs doublets. Moreover, by making a simple $ans\ddot{a}tz$ we extract $\mathcal{M}_l {\mathcal{M}_l}^\dagger$ for the charged lepton sector. A similar $ans\ddot{a}tz$ is proposed for the quark sector. The sources of masses for the neutrinos are entirely different from those for the charged leptons and for the quarks and this might explain why $U_{PMNS}$ is {\em very different} from $V_{CKM}$.Comment: 19 pages. Two figure

Is There a Size-Induced Market Failure in Skills Training?

A skilled and educated workforce can support the competitiveness of enterprises of all sizes. However, smaller firms may face greater challenges in developing human capital. We explore differences between smaller and larger firms in offering skills training and in hiring workers with more formal education. Drawing on a dataset of enterprises in five Asian countries, we find major size-based differences in education and training. While smaller firms train less, they also are less inclined to view an inadequately skilled workforce as a major constraint on their operations. It may be that smaller firms are content to occupy niches in a low-skills equilibrium. Our empirical results do offer the possibility, however, that a size-induced market failure in skills training may coexist with a lower regard for skills. The policy implications are not only that governments can reduce the costs for firms to train, but also that micro and small firms need to be sensitized to the benefits of skills upgrading

State and input simultaneous estimation for a class of time-delay systems with uncertainties

This brief addresses the problem of estimation of both the states and the unknown inputs of a class of systems that are subject to a time-varying delay in their state variables, to an unknown input, and also to an additive uncertain, nonlinear disturbance. Conditions are derived for the solvability of the design matrices of a reduced-order observer for state and input estimation, and for the stability of its dynamics. To improve computational efficiency, a delay-dependent asymptotic stability condition is then developed using the linear matrix inequality formulation. A design procedure is proposed and illustrated by a numerical example.<br /

Lepton Flavor Violating Radiative Decays in EW-Scale νR\nu_R Model: An Update

We perform an updated analysis for the one-loop induced lepton flavor violating radiative decays $l_i \to l_j \gamma$ in an extended mirror model. Mixing effects of the neutrinos and charged leptons constructed with a horizontal $A_4$ symmetry are also taken into account. Current experimental limit and projected sensitivity on the branching ratio of $\mu \to e \gamma$ are used to constrain the parameter space of the model. Calculations of two related observables, the electric and magnetic dipole moments of the leptons, are included. Implications concerning the possible detection of mirror leptons at the LHC and the ILC are also discussed.Comment: 9 figures, 36 single-side pages. Updated email addresses and referenc

Observer-based control of multi-agent systems under decentralized information structure

This paper addresses the problem of decentralized implementation of a global state feedback controller for multi-agent systems. The system is assumed to be under the constraint of a complete decentralized information structure. The decentralization of the control task is achieved through the construction of low-order decentralized functional observers with the purpose of generating the required corresponding control signal for each local control station. A design procedure is developed for obtaining an approximate solution to the design of the observers. Stability analysis is provided for the global system using the proposed observer-based approach. A numerical example is given to illustrate the design procedure and cases when the observers\u27 order increases from the lowest value. <br /

Strategic Differentiation of High-Tech Services in Local Hospital Markets

This study assesses organizational and market factors related to high-tech service differentiation in local hospital markets. The sample includes 1704 nonfederal, general acute hospitals in urban counties in the United States. We relate organizational and market factors in 2011 to service differentiation in 2013, using ordinary least squares regression. Data are compiled from the American Hospital Association Annual Survey of Hospitals, Area Resource File, and Centers for Medicare and Medicaid Services. Results show that hospitals differentiate more services relative to market rivals if they are larger than the rival and if the hospitals are further apart geographically. Hospitals differentiate more services if they are large, teaching, and nonprofit or public and if they face more market competition. Hospitals differentiate fewer services from rivals if they belong to multihospital systems. The findings underscore the pressures that urban hospitals face to offer high-tech services despite the potential of high-tech services to drive hospital costs upward

A low-order linear functional observer for time delay systems

This paper presents an efficient technique to design low order state function observers for linear time-delay systems. Assuming the existence of a linear state feedback controller to achieve stability or some control performance criteria of the time-delay system, a design procedure is proposed forreconstruction of the state feedback control action. The procedure involves solving an optimisation problem with the objective to generate a matrix that is as close as possible to the given feedback gain of the required feedback controller. A condition for robust stability of the time-delay system using the observer-based control scheme is given. The attractive features of the proposed design procedure are that the resulted linear functional state observer is of a very low order and it requires information of a small number of outputs. Numerical examples are given to demonstrate the design procedure and its merits.<br /

Groups of two galaxies in SDSS: implications of colours on star formation quenching time-scales

We have devised a method to select galaxies that are isolated in their dark matter halo (N=1 systems) and galaxies that reside in a group of exactly two (N=2 systems). Our N=2 systems are widely-separated (up to $\sim$\,200\,$h^{-1}$\,kpc), where close galaxy-galaxy interactions are not dominant. We apply our selection criteria to two volume-limited samples of galaxies from SDSS DR6 with $M_{r}-5 \log_{10} h \leq$ -19 and -20 to study the effects of the environment of very sparse groups on galaxy colour. For satellite galaxies in a group of two, we find a red excess attributed to star formation quenching of 0.15\,$\pm$\,0.01 and 0.14\,$\pm$\,0.01 for the -19 and -20 samples, respectively, relative to isolated galaxies of the same stellar mass. Assuming N=1 systems are the progenitors of N=2 systems, an immediate-rapid star formation quenching scenario is inconsistent with these observations. A delayed-then-rapid star formation quenching scenario with a delay time of 3.3 and 3.7\,Gyr for the -19 and -20 samples, respectively, yields a red excess prediction in agreement with the observations. The observations also reveal that central galaxies in a group of two have a slight blue excess of 0.06\,$\pm$\,0.02 and 0.02\,$\pm$\,0.01 for the -19 and -20 samples, respectively, relative to N=1 populations of the same stellar mass. Our results demonstrate that even the environment of very sparse groups of luminous galaxies influence galaxy evolution and in-depth studies of these simple systems are an essential step towards understanding galaxy evolution in general.Comment: 17 pages, 11 figures, accepted to MNRA

The Southern Conference for Human Welfare and the Decade of Hope, 1938-1948

Thesis advisor: Alan LawsonBefore the Civil Rights Movement began in the mid-1950s, an early movement led by white southern liberals fought for social and economic equality between the races. These men and women defied the stereotypes of bigoted white southerners and gradualist appeasers and challenged the norms and social customs of their region. Unfortunately, their legacy and accomplishments have largely been overshadowed by dramatic events of 1950s and 1960s. This thesis seeks to reexamine their work in view of their courage and unwavering determination to bring justice and equality to the South.Thesis (BA) — Boston College, 2009.Submitted to: Boston College. College of Arts and Sciences.Discipline: History Honors Program.Discipline: College Honors Program.Discipline: History