Strategies to link tiny neutrino masses with huge missing mass of the Universe

With the start of the LHC, interest in electroweak scale models for the neutrino mass has grown. In this letter, we review two specific models that simultaneously explain neutrino masses and provide a suitable DM candidate. We discuss the implications of these models for various observations and experiments including the LHC, Lepton Flavor Violating (LFV) rare decays, direct and indirect dark matter searches and Kaon decay.Comment: 17 pages, one diagram, talk given at International Conference on Flavor Physics in the LHC era in Singapor

SLIM at LHC: LHC search power for a model linking dark matter and neutrino mass

Recently a model has been proposed that links dark matter and neutrino masses. The dark matter candidate which is dubbed as SLIM has a mass of MeV scale and can show up at low energy experiments. The model also has a high energy sector which consists of a scalar doublet, $(\phi^-, \phi^0)$. We discuss the potential of the LHC for discovering the new scalars. We focus on the $\phi^+\phi^-$ and $\phi^{\pm} \phi^0$ production and the subsequent decay of the charged scalar to a charged lepton and the SLIM which appears as missing energy. Identifying the background, we estimate the signal significance and find that it can exceed $5 \sigma$ at 30 ${\rm fb}^{-1}$ for the 14 TeV run at the LHC. We comment on the possibility of extracting the flavor structure of the Yukawa couplings which also determine the neutrino mass matrix. Finally, we discuss the prospects of this search at the current 7 TeV run of the LHC.Comment: 26 pages, 21 figure

Are small neutrino masses unveiling the missing mass problem of the Universe?

We present a scenario in which a remarkably simple relation linking dark matter properties and neutrino masses naturally emerges. This framework points towards a low energy theory where the neutrino mass originates from the existence of a light scalar dark matter particle in the MeV mass range. A very surprising aspect of this scenario is that the required MeV dark matter is one of the favoured candidates to explain the mysterious emission of 511 keV photons in the centre of our galaxy. A possible interpretation of these findings is that dark matter is the stepping stone of a theory beyond the standard model instead of being an embarrassing relic whose energy density must be accounted for in any successful model building.Comment: 4pages, 2 figures. Two paragraphs have been added. One for the complex case; the other one for the UV completio

My friends are here! Why talk to "Strangers"?

Many online communities face the challenge of incorporating a stable inux of newcomers into the community. Research on socialization in offine organizations suggest that newcomers who join an organization with a cohort of other newcomers are more likely to succeed in the organization. We have studied the effect of socializing a cohort of newcomers who share common offine identity into an online community. Our results suggest that cohort support can improve newcomers' performance but it might hinder communication with existing members of the community

The interferon-stimulated gene IFITM3 restricts infection and pathogenesis of arthritogenic and encephalitic alphaviruses

Host cells respond to viral infections by producing type I interferon (IFN), which induces the expression of hundreds of interferon-stimulated genes (ISGs). Although ISGs mediate a protective state against many pathogens, the antiviral functions of the majority of these genes have not been identified. IFITM3 is a small transmembrane ISG that restricts a broad range of viruses, including orthomyxoviruses, flaviviruses, filoviruses, and coronaviruses. Here, we show that alphavirus infection is increased in Ifitm3(−/−) and Ifitm locus deletion (Ifitm-del) fibroblasts and, reciprocally, reduced in fibroblasts transcomplemented with Ifitm3. Mechanistic studies showed that Ifitm3 did not affect viral binding or entry but inhibited pH-dependent fusion. In a murine model of chikungunya virus arthritis, Ifitm3(−/−) mice sustained greater joint swelling in the ipsilateral ankle at days 3 and 7 postinfection, and this correlated with higher levels of proinflammatory cytokines and viral burden. Flow cytometric analysis suggested that Ifitm3(−/−) macrophages from the spleen were infected at greater levels than observed in wild-type (WT) mice, results that were supported by experiments with Ifitm3(−/−) bone marrow-derived macrophages. Ifitm3(−/−) mice also were more susceptible than WT mice to lethal alphavirus infection with Venezuelan equine encephalitis virus, and this was associated with greater viral burden in multiple organs. Collectively, our data define an antiviral role for Ifitm3 in restricting infection of multiple alphaviruses. IMPORTANCE The interferon-induced transmembrane protein 3 (IFITM3) inhibits infection of multiple families of viruses in cell culture. Compared to other viruses, much less is known about the antiviral effect of IFITM3 on alphaviruses. In this study, we characterized the antiviral activity of mouse Ifitm3 against arthritogenic and encephalitic alphaviruses using cells and animals with a targeted gene deletion of Ifitm3 as well as deficient cells transcomplemented with Ifitm3. Based on extensive virological analysis, we demonstrate greater levels of alphavirus infection and disease pathogenesis when Ifitm3 expression is absent. Our data establish an inhibitory role for Ifitm3 in controlling infection of alphaviruses

Conceptualizing Multiagency Emergency Management System as Joint Cognitive System

PresentationEmergency management system (EMS) provides a crucial barrier for the protection of socio-ecological infrastructure from man-made disasters and natural threats. To meet diverse demands from hazardous events, resilience engineering is considered as an effective approach to enhance the performance of EMS. While conceptual and qualitative descriptions of resilience are abundant, ideas of operationalizing resilience are scarce. In this regard, the present work redefines resilience in the EMS and proposes a framework of measuring resilience by abstracting the EMS as a joint cognitive system

Leptonic CP violation: zero, maximal or between the two extremes

Discovery of the CP-violation in the lepton sector is one of the challenges of the particle physics. We search for possible principles, symmetries and phenomenological relations that can lead to particular values of the CP-violating Dirac phase, $\delta$. In this connection we discuss two extreme cases: the zero phase, $\delta = 0$, and the maximal CP-violation, $\delta = \pm \pi/2$, and relate them to the peculiar pattern of the neutrino mixing. The maximal CP-violation can be related to the $\nu_\mu - \nu_\tau$ reflection symmetry. We study various aspects of this symmetry and introduce a generalized reflection symmetry that can lead to an arbitrary phase that depends on the parameter of the symmetry transformation. The generalized reflection symmetry predicts a simple relation between the Dirac and Majorana phases. We also consider the possibility of certain relations between the CP-violating phases in the quark and lepton sectors.Comment: 34 pages, no figures; v3: version appeared in JHE

Progressor: Social navigation support through open social student modeling

The increased volumes of online learning content have produced two problems: how to help students to find the most appropriate resources and how to engage them in using these resources. Personalized and social learning have been suggested as potential ways to address these problems. Our work presented in this paper combines the ideas of personalized and social learning in the context of educational hypermedia. We introduce Progressor, an innovative Web-based tool based on the concepts of social navigation and open student modeling that helps students to find the most relevant resources in a large collection of parameterized self-assessment questions on Java programming. We have evaluated Progressor in a semester-long classroom study, the results of which are presented in this paper. The study confirmed the impact of personalized social navigation support provided by the system in the target context. The interface encouraged students to explore more topics attempting more questions and achieving higher success rates in answering them. A deeper analysis of the social navigation support mechanism revealed that the top students successfully led the way to discovering most relevant resources by creating clear pathways for weaker students. © 2013 Taylor and Francis Group, LLC