HiJAKing innate lymphoid cells?

The family of innate lymphoid cells (ILCs) consists of a heterogeneous group of cytokine-producing cells that have features in common with adaptive T helper (Th) cells. Cytokines acting through the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways are key players in both Th and ILC biology. Observations in animal models, supported by evidence from humans, have highlighted the importance of the downstream events evoked by the cytokines that signal through the common IL-2 γ-chain receptor. Similarly, it is reasonable to assume that therapeutic targeting of this signaling cascade will also modulate ILC effector function in disease. Since a major limitation of gene knockout studies in mice is the complete loss of ILC populations, including NK cells, we believe that an attractive, alternative, strategy would be to study the role of cytokine signaling in the regulation of ILC function by pharmacological manipulation of these pathways instead. Here, we discuss the potential of JAK inhibitors as a drug class to elucidate mechanisms underlying ILC biology and to inform the design of new therapeutic strategies for inflammatory and autoimmune disorders

Massive Higher Spin States in String Theory and the Principle of Equivalence

In this paper we study three point functions of the Type II superstring involving one graviton and two massive states, focusing in particular on the spin-7/2 fermions at the first mass level. Defining a gravitational quadrupole ``h-factor'', we find that the non-minimal interactions of string states in general are parametrized by $h\ne1$, in contrast to the preferred field theory value of h=1 (for tree-level unitarity). This difference arises from the fact that consistent gravitational interactions of strings are related to the presence of a complete tower of massive states, not present in the ordinary field theory case.Comment: 14 pages, plain Te

Spectator Effects in Inclusive Decays of Beauty Hadrons

We evaluate the matrix elements of the four-quark operators which contribute to the lifetimes of $B$-mesons and the $\Lambda_b$-baryon. We find that the spectator effects are not responsible for the discrepancy between the theoretical prediction and experimental measurement of the ratio of lifetimes $\tau(\Lambda_b)/\tau(B)$.Comment: LATTICE98. 3 pages, no figure

Curvature perturbations from dimensional decoupling

The scalar modes of the geometry induced by dimensional decoupling are investigated. In the context of the low energy string effective action, solutions can be found where the spatial part of the background geometry is the direct product of two maximally symmetric Euclidean manifolds whose related scale factors evolve at a dual rate so that the expanding dimensions first accelerate and then decelerate while the internal dimensions always contract. After introducing the perturbative treatment of the inhomogeneities, a class of five-dimensional geometries is discussed in detail. Quasi-normal modes of the system are derived and the numerical solution for the evolution of the metric inhomogeneities shows that the fluctuations of the internal dimensions provide a term that can be interpreted, in analogy with the well-known four-dimensional situation, as a non-adiabatic pressure density variation. Implications of this result are discussed with particular attention to string cosmological scenarios.Comment: 25 pages, 3 figure

Time-dependent gravitating solitons in five dimensional warped space-times

Time-dependent soliton solutions are explicitly derived in a five-dimensional theory endowed with one (warped) extra-dimension. Some of the obtained geometries, everywhere well defined and technically regular, smoothly interpolate between two five-dimensional anti-de Sitter space-times for fixed value of the conformal time coordinate. Time dependent solutions containing both topological and non-topological sectors are also obtained. Supplementary degrees of freedom can be also included and, in this case, the resulting multi-soliton solutions may describe time-dependent kink-antikink systems.Comment: 19 pages, 10 figure

Susceptibility of the QCD vacuum to CP-odd electromagnetic background fields

We investigate two flavor QCD in presence of CP-odd electromagnetic background fields and determine, by means of lattice QCD simulations, the induced effective theta term to the first order in the scalar product of E and B. We employ a rooted staggered discretization and study lattice spacings down to 0.1 fm and Goldstone pion masses around 480 MeV. In order to deal with a positive measure, we consider purely imaginary electric fields and real magnetic fields, then exploiting analytic continuation. Our results are relevant to a description of the effective pseudoscalar QED-QCD interactions.Comment: 5 pages, 4 figures, 1 table. New data and references added. Matches the published versio

Subjective probabilities: psychological theories and economic applications

Abbigail J. Chiodo, Massimo Guidolin, Michael T. Owyang, and Makoto Shimoji> Real-life decisionmakers are often forced to estimate the likelihood of uncertain future events. Usually, economists assume that these agents behave in a fully rational manner, employing statistical rules to assess probabilities, and that they maximize expected utility. Psychological studies, however, have shown that people do not tend to behave as rational models would predict. The authors review three rules of thumb taken from the psychology literature that people rely on when assessing the likelihood of uncertain events. The authors construct a simple model of belief formation that incorporates these rules and then present one formal and three illustrative applications showing how these psychological phenomena cause deviations from anticipated economic outcomes.Economic conditions ; Prediction (Psychology)

Subjective probabilities: psychological evidence and economic applications

Real-life decision makers are often forced to estimate the likelihood of uncertain future events. Usually, economists assume that agents behave as though they are fully rational, employing statistical rules to assess probabilities, and that they maximize expected utility. Psychological studies, however, have shown that people tend not to adhere to these rationality postulates. We review three rules of thumb taken from the psychology literature that people have been shown to rely on when assessing the likelihood of uncertain events. We construct a simple model of belief formation that incorporates these rules and present one formal and two illustrative applications in which these psychological phenomena cause deviations from anticipated economic outcomes.Economic conditions ; Prediction (Psychology)

Armchair graphene nanoribbons: PT-symmetry breaking and exceptional points without dissipation

We consider a single layer graphene nanoribbon with armchair edges in a longitudinally constant external potential and point out that its transport properties can be described by means of an effective non-Hermitian Hamiltonian. We show that this system has some features typical of dissipative systems, namely the presence of exceptional points and of PT-symmetry breaking, although it is not dissipative.Comment: 5 pages, 2 eps figure

Confining properties of QCD at finite temperature and density

A disorder parameter detecting dual superconductivty of the vacuum is used as a probe to characterize the confining properties of the phase diagram of two color QCD at finite temperature and density. We obtain evidence for the disappearing of dual superconductivity (deconfinement) induced by a finite density of baryonic matter, as well as for a coincidence of this phenomenon with the restoration of chiral symmetry both at zero and finite density. The saturation transition induced by Pauli blocking is studied as well, and a general warning is given about the possible effects that this unphysical transition could have on the study of the QCD phase diagram at strong values of the gauge coupling.Comment: 13 pages, 23 figure