634 research outputs found
Forecasting Inflation using Economic Indicators: the Case of France
In order to provide short run forecasts of headline and core HICP inflation for France, we assess the forecasting performance of a large set of economic indicators, individually and jointly, as well as using dynamic factor models. We run out-of-sample forecasts implementing the Stock and Watson (1999) methodology. It turns out that, according to usual statistical criteria, the combination of several indicators -in particular those derived from surveys- provides better results than dynamic factor models, even after pre-selection of the variables included in the panel. However, factors included in VAR models exhibit more stable forecasting performance over time. Results for HICP excluding unprocessed food and energy are very encouraging. Moreover, we show that it is possible to use forecasts on this indicator to project overall inflation.Inflation ; Out-of-sample forecast ; Indicator models ; Dynamic factor models ; Phillips curve.
A Tight Connection Between Direct and Indirect Detection of Dark Matter through Higgs Portal Couplings to a Hidden Sector
We present a hidden Abelian extension of the Standard Model including a
complex scalar as a dark matter candidate and a light scalar acting as a long
range force carrier between dark matter particles. The Sommerfeld enhanced
annihilation cross-section of the dark matter explains the observed cosmic ray
excesses. The light scalar field also gives rise to potentially large
cross-sections of dark matter on nucleon, therefore providing an interesting
way to probe this model simultaneously at direct and indirect dark matter
search experiments. We constrain the parameter-space of the model by taking
into account CDMS-II exclusion limit as well as PAMELA and FermiLAT data.Comment: 15 pages, 7 figures. Added discussions on tuning and inverse Compton
scattering constraints. References added and updated. Matches the published
versio
HIV-1 DIS stem loop forms an obligatory bent kissing intermediate in the dimerization pathway.
The HIV-1 dimerization initiation sequence (DIS) is a conserved palindrome in the apical loop of a conserved hairpin motif in the 5′-untranslated region of its RNA genome. DIS hairpin plays an important role in genome dimerization by forming a ‘kissing complex’ between two complementary hairpins. Understanding the kinetics of this interaction is key to exploiting DIS as a possible human immunodeficiency virus (HIV) drug target. Here, we present a single-molecule Förster resonance energy transfer (smFRET) study of the dimerization reaction kinetics. Our data show the real-time formation and dissociation dynamics of individual kissing complexes, as well as the formation of the mature extended duplex complex that is ultimately required for virion packaging. Interestingly, the single-molecule trajectories reveal the presence of a previously unobserved bent intermediate required for extended duplex formation. The universally conserved A272 is essential for the formation of this intermediate, which is stabilized by Mg(2+), but not by K(+) cations. We propose a 3D model of a possible bent intermediate and a minimal dimerization pathway consisting of three steps with two obligatory intermediates (kissing complex and bent intermediate) and driven by Mg(2+) ions
Gene expression and cytokine monitoring for biodosimetry and radiation sensitivity screening (GYMBRASS)
Flavour Matters in Leptogenesis
We give analytic approximations to the baryon asymmetry produced by thermal
leptogenesis with hierarchical right-handed neutrinos. Our calculation includes
flavour-dependent washout processes and CP violation in scattering, and
neglects gauge interactions and finite temperature corrections. Our approximate
formulae depend upon the three CP asymmetries in the individual lepton flavours
as well as on three flavour-dependent efficiency factors. We show that the
commonly used expressions for the lepton asymmetry, which depend on the total
CP asymmetry and one single efficiency factor, may fail to reproduce the
correct lepton asymmetry in a number of cases. We illustrate the importance of
using the flavour-dependent formulae in the context of a two right-handed
neutrino model.Comment: Additional typos corrected (in particular, the plots and captions now
agree
Study of flavour dependencies in leptogenesis
We study the impact of flavours on the efficiency factors and give analytical
and numerical results of the baryon asymmetry taking into account the different
charged lepton Yukawa contributions and the complete (diagonal and
off-diagonal) to conversion matrix. With this treatment we update
the lower bound on the lightest right-handed neutrino mass.Comment: 13 pages, 11 figures. typos corrected, some formulae modified. 2
figures and discussion adde
Leptogenesis beyond the limit of hierarchical heavy neutrino masses
We calculate the baryon asymmetry of the Universe in thermal leptogenesis
beyond the usual lightest right-handed (RH) neutrino dominated scenario (N_1DS)
and in particular beyond the hierarchical limit (HL), M_1 << M_2 << M_3, for
the RH neutrino mass spectrum. After providing some orientation among the large
variety of models, we first revisit the central role of the N_1DS, with new
insights on the dynamics of the asymmetry generation and then discuss the main
routes departing from it, focusing on models beyond the HL. We study in detail
two examples of `strong-strong' wash-out scenarios: one with `maximal phase'
and the limit of very large M_3, studying the effects arising when
delta_2=(M_2-M_1)/M_1 is small. We extend analytical methods already applied to
the N_1DS showing, for example, that, in the degenerate limit (DL), the
efficiency factors of the RH neutrinos become equal with the single decay
parameter replaced by the sum. Both cases disprove the misconception that close
RH neutrino masses necessarily lead to a final asymmetry enhancement and to a
relaxation of the lower bounds on M_1 and on the initial temperature of the
radiation-dominated expansion. We also explain why leptogenesis tends to favor
normal hierarchy compared to inverted hierarchy for the left-handed neutrino
masses.Comment: 30 pages, 8 figures; corrected typo in Eq. (67); shortened
Introduction, Section 3 and Conclusions; one figure removed; added 2
references; to appear in JCA
CP violation in scatterings, three body processes and the Boltzmann equations for leptogenesis
We obtain the Boltzmann equations for leptogenesis including decay and
scattering processes with two and three body initial or final states. We
present an explicit computation of the CP violating scattering asymmetries. We
analyze their possible impact in leptogenesis, and we discuss the validity of
their approximate expressions in terms of the decay asymmetry. In scenarios in
which the initial heavy neutrino density vanishes, the inclusion of CP
asymmetries in scatterings can enforce a cancellation between the lepton
asymmetry generated at early times and the asymmetry produced at later times.
We argue that a sizeable amount of washout is crucial for spoiling this
cancellation, and we show that in the regimes in which the washouts are
particularly weak, the inclusion of CP violation in scatterings yields a
reduction in the final value of the lepton asymmetry. In the strong washout
regimes the inclusion of CP violation in scatterings still leads to a
significant enhancement of the lepton asymmetry at high temperatures; however,
due to the independence from the early conditions that is characteristic of
these regimes, the final value of the lepton asymmetry remains approximately
unchanged.Comment: 24 pages, 6 figures. One appendix added. Some numerical results and
corresponding figures (mainly fig. 3) corrected. Final version to be
published in JHE
Synthesis, Electrochemistry, and Excited-State Properties of Three Ru(II) Quaterpyridine Complexes
The complexes [Ru(qpy)LL′]2+ (qpy = 2,2′:6′,2″:6″,2‴-quaterpyridine), with 1: L = acetonitrile, L′= chloride; 2: L = L′= acetonitrile; and 3: L = L′= vinylpyridine, have been prepared from [Ru(qpy) (Cl)2]. Their absorption spectra in CH3CN exhibit broad metal-to-ligand charge transfer (MLCT) absorptions arising from overlapping 1A1 → 1MLCT transitions. Photoluminescence is not observed at room temperature, but all three are weakly emissive in 4:1 ethanol/methanol glasses at 77 K with broad, featureless emissions observed between 600 and 1000 nm consistent with MLCT phosphorescence. Cyclic voltammograms in CH3CN reveal the expected RuIII/II redox couples. In 0.1 M trifluoroacetic acid (TFA), 1 and 2 undergo aquation to give [RuII(qpy)(OH2)2]2+, as evidenced by the appearance of waves for the couples [RuIII(qpy)(OH2)2]3+/[RuII(qpy)(OH2)2]2+, [RuIV(qpy)(O)(OH2)]2+/[RuIII(qpy)(OH2)2]3+, and [RuVI(qpy)(O)2]2+/[RuIV(qpy)(O)(OH2)]2+ in cyclic voltammograms
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