1,464 research outputs found
Does money matter in inflation forecasting?.
This paper provides the most fully comprehensive evidence to date on whether or not monetary aggregates are valuable for forecasting US inflation in the early to mid 2000s. We explore a wide range of different definitions of money, including different methods of aggregation and different collections of included monetary assets. In our forecasting experiment we use two non-linear techniques, namely, recurrent neural networks and kernel recursive least squares regression - techniques that are new to macroeconomics. Recurrent neural networks operate with potentially unbounded input memory, while the kernel regression technique is a finite memory predictor. The two methodologies compete to find the best fitting US inflation forecasting models and are then compared to forecasts from a naive random walk model. The best models were non-linear autoregressive models based on kernel methods. Our findings do not provide much support for the usefulness of monetary aggregates in forecasting inflation
An HST/COS legacy survey of intervening SiIII absorption in the extended gaseous halos of low-redshift galaxies
Doubly ionized silicon (SiIII) is a powerful tracer of diffuse ionized gas
inside and outside of galaxies. It can be observed in the local Universe in
ultraviolet (UV) absorption against bright extragalactic background sources. We
here present an extensive study of intervening SiIII-selected absorbers and
their relation to the circumgalactic medium (CGM) of galaxies at low redshift
(z<=0.1), based on the analysis of UV absorption spectra along 303
extragalactic lines of sight obtained with the Cosmic Origins Spectrograph
(COS) on board the Hubble Space Telescope (HST). Along a total redshift path of
Dz=24 we identify 69 intervening SiIII systems that all show associated
absorption from other low and high ions. We derive a bias-corrected number
density of dN/dz(SiIII)=2.5 for absorbers with column densities log
N(SiIII)>12.2. We develop a geometrical model for the absorption-cross section
of the CGM around the local galaxy population and find excellent agreement
between the model predictions and the observations. We further compare
redshifts and positions of the absorbers with that of ~64,000 galaxies using
archival galaxy-survey data. For the majority of the absorbers we identify
possible host galaxies within 300 km/s of the absorbers and derive impact
parameters rho<200 kpc, demonstrating that the spatial distributions of SiIII
absorbers and galaxies are highly correlated. Our study indicates that the
majority of SiIII-selected absorbers in our sample trace the CGM of nearby
galaxies within their virial radii at a typical covering fraction of ~70 per
cent. From a detailed ionization model we estimate that diffuse gas in the CGM
around galaxies, as traced by SiIII, contains substantially more baryonic mass
than their neutral interstellar medium.Comment: 32 pages, 17 figures; final version accepted for publication in A&
Evolution, recurrency and kernels in learning to model inflation
This paper provides the most fully comprehensive evidence to date on whether or not monetary aggregates are valuable for forecasting US inflation in the early to mid 2000s. We explore a wide range of different definitions of money, including different methods of aggregation and different collections of included monetary assets. We use non-linear, artificial intelligence techniques, namely, recurrent neural networks, evolution strategies and kernel methods in our forecasting experiment. In the experiment, these three methodologies compete to find the best fitting US inflation forecasting models and are then compared to forecasts from a naive random walk model. The best models were non-linear autoregressive models based on kernel methods. Our findings do not provide much support for the usefulness of monetary aggregates in forecasting inflation. There is evidence in the literature that evolutionary methods can be used to evolve kernels hence our future work should combine the evolutionary and kernel methods to get the benefits of both
Controlled lasing from active optomechanical resonators
Planar microcavities with distributed Bragg reflectors (DBRs) host, besides
confined optical modes, also mechanical resonances due to stop bands in the
phonon dispersion relation of the DBRs. These resonances have frequencies in
the sub-terahertz (10E10-10E11 Hz) range with quality factors exceeding 1000.
The interaction of photons and phonons in such optomechanical systems can be
drastically enhanced, opening a new route toward manipulation of light. Here we
implemented active semiconducting layers into the microcavity to obtain a
vertical-cavity surface-emitting laser (VCSEL). Thereby three resonant
excitations -photons, phonons, and electrons- can interact strongly with each
other providing control of the VCSEL laser emission: a picosecond strain pulse
injected into the VCSEL excites long-living mechanical resonances therein. As a
result, modulation of the lasing intensity at frequencies up to 40 GHz is
observed. From these findings prospective applications such as THz laser
control and stimulated phonon emission may emerge
Giant increase in the metal-enhanced fluorescence of organic molecules in nanoporous alumina templates and large molecule-specific red/blue shift of the fluorescence peak
The fluorescence of organic fluorophore molecules is enhanced when they are
placed in contact with certain metals (Al, Ag, Cu, Au, etc.) whose surface
plasmon waves couple into the radiative modes of the molecules and increase the
radiative efficiency. Here, we report a hitherto unknown size dependence of
this metal enhanced fluorescence (MEF) effect in the nanoscale. When the
molecules are deposited in nanoporous anodic alumina films with exposed
aluminum at the bottom of the pores, they form organic nanowires standing on
aluminum nanoparticles whose plasmon waves have much larger amplitudes. This
increases the MEF strongly, resulting in several orders of magnitude increase
in the fluorescence intensity of the organic fluorophores. The increase in
intensity shows an inverse super-linear dependence on nanowire diameter because
the nanowires also act as plasmonic 'waveguides' that concentrate the plasmons
and increase the coupling of the plasmons with the radiative modes of the
molecules. Furthermore, if the nanoporous template housing the nanowires has
built-in electric fields due to space charges, a strong molecule-specific red-
or blue-shift is induced in the fluorescence peak owing to a renormalization of
the dipole moment of the molecule. This can be exploited to detect minute
amounts of target molecules in a mixture using their optical signature
(fluorescence) despite the presence of confounding background signals. It can
result in a unique new technology for bio- and chemical-sensing
Erenumab in chronic migraine: Patient-reported outcomes in a randomized double-blind study.
OBJECTIVE: To determine the effect of erenumab, a human monoclonal antibody targeting the calcitonin gene-related peptide receptor, on health-related quality of life (HRQoL), headache impact, and disability in patients with chronic migraine (CM).
METHODS: In this double-blind, placebo-controlled study, 667 adults with CM were randomized (3:2:2) to placebo or erenumab (70 or 140 mg monthly). Exploratory endpoints included migraine-specific HRQoL (Migraine-Specific Quality-of-Life Questionnaire [MSQ]), headache impact (Headache Impact Test-6 [HIT-6]), migraine-related disability (Migraine Disability Assessment [MIDAS] test), and pain interference (Patient-Reported Outcomes Measurement Information System [PROMIS] Pain Interference Scale short form 6b).
RESULTS: Improvements were observed for all endpoints in both erenumab groups at month 3, with greater changes relative to placebo observed at month 1 for many outcomes. All 3 MSQ domains were improved from baseline with treatment differences for both doses exceeding minimally important differences established for MSQ-role function-restrictive (≥3.2) and MSQ-emotional functioning (≥7.5) and for MSQ-role function-preventive (≥4.5) for erenumab 140 mg. Changes from baseline in HIT-6 scores at month 3 were -5.6 for both doses vs -3.1 for placebo. MIDAS scores at month 3 improved by -19.4 days for 70 mg and -19.8 days for 140 mg vs -7.5 days for placebo. Individual-level minimally important difference was achieved by larger proportions of erenumab-treated participants than placebo for all MSQ domains and HIT-6. Lower proportions of erenumab-treated participants had MIDAS scores of severe (≥21) or very severe (≥41) or PROMIS scores ≥60 at month 3.
CONCLUSIONS: Erenumab-treated patients with CM experienced clinically relevant improvements across a broad range of patient-reported outcomes.
CLINICALTRIALSGOV IDENTIFIER: NCT02066415.
CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with CM, erenumab treatment improves HRQoL, headache impact, and disability
Time course of salivary protein responses to cranberry-derived polyphenol exposure as a function of PROP taster status
Astringency is a complex oral sensation, commonly experienced when dietary polyphenols interact with salivary proteins. Most astringent stimuli alter protein levels, which then require time to be replenished. Although it is standard practice in astringency research to provide breaks in between stimuli, there is limited consensus over the amount of time needed to restore the oral environment to baseline levels. Here we examined salivary protein levels after exposure to 20 mL of a model stimulus (cranberry polyphenol extract, 0.75 g/L CPE) or unsweetened cranberry juice (CJ), over a 10 min period. Whole saliva from healthy subjects (n = 60) was collected at baseline and after 5 and 10 min following either stimulus. Five families of proteins: basic proline-rich proteins (bPRPs); acidic proline-rich proteins (aPRPs); histatins; statherin; and S-type cystatins, were analyzed in whole saliva via HPLC-low resolution-ESI-IT-MS, using the area of the extracted ion current (XIC) peaks. Amylase was quantified via immunoblotting. In comparison to baseline (resting), both stimuli led to a rise in levels of aPRPs (p < 0.000) at 5 min which remained elevated at 10 min after stimulation. Additionally, an interaction of PROP taster status and time was observed, wherein super-tasters had higher levels of amylase in comparison to non-tasters after stimulation with CJ at both timepoints (p = 0.014–0.000). Further, male super-tasters had higher levels of bPRPs at 5 min after stimulation with both CJ and CPE (p = 0.015–0.007) in comparison to baseline. These data provide novel findings of interindividual differences in the salivary proteome that may influence the development of astringency and that help inform the design of sensory experiments of astringency
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