342 research outputs found
A beta based framework for (lower) bond risk premia.
We use a no-arbitrage essentially affine three-factor model to estimate term premia in US and German ten-year government bond yields. In line with the existing literature, we find that estimated premia have followed a downward trend since the 1980s: from 4.9 per cent in 1981 to 0.7 per cent in 2006 for the US bond and from 3.3 to 0.5 per cent for the German one. Subsequently, using an Error Correction Model (ECM) we prove that the decline is explained by a decrease in global output variability and an increase in the power of ten-year government bonds to diversify the investorsâ portfolios. In addition, the ECM also forecasts both the US and the German term premia converging to around one percentage point over a five year horizon. Long-term return expectations for ten-year government bonds will have to incorporate bond risk premia that - while in line with average excess returns during the twentieth century - are significantly lower than average excess returns over the last two decades.Term structure model, bond risk premium, modern portfolio theory
The transmission of monetary policy shocks from the US to the euro area
This paper studies the transmission of monetary policy shocks from the US to the euro-area using a two-country structural VAR with no exogeneity assumption. The analysis reveals the following results. First, in response to an unexpected increase in the Federal funds rate, the euro immediately depreciates with respect to the dollar and then appreciates in line with the prediction of the uncovered interest parity condition. Second, there is evidence of a temporary positive spillover to euro-area output in the short run, while a negative effect emerges in the medium run. Third, the contribution of the trade balance channel to the transmission of monetary shocks is negligible. Finally, the degree of pass-through of the exchange rate changes onto euro-area consumer prices is incomplete and small in the short run, while it is close to zero in the medium run.VAR, Monetary Policy, International transmission
Eulerian and Lagrangian solutions to the continuity and Euler equations with vorticity
In the first part of this paper we establish a uniqueness result for
continuity equations with velocity field whose derivative can be represented by
a singular integral operator of an function, extending the Lagrangian
theory in \cite{BouchutCrippa13}. The proof is based on a combination of a
stability estimate via optimal transport techniques developed in \cite{Seis16a}
and some tools from harmonic analysis introduced in \cite{BouchutCrippa13}. In
the second part of the paper, we address a question that arose in
\cite{FilhoMazzucatoNussenzveig06}, namely whether 2D Euler solutions obtained
via vanishing viscosity are renormalized (in the sense of DiPerna and Lions)
when the initial data has low integrability. We show that this is the case even
when the initial vorticity is only in~, extending the proof for the
case in \cite{CrippaSpirito15}
Programming, metabolic syndrome, and NAFLD: The challenge of transforming a vicious cycle into a virtuous cycle
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Deep Learning, Feature Learning, and Clustering Analysis for SEM Image Classification
In this paper, we report upon our recent work aimed at improving and adapting machine learning algorithms to automatically classify nanoscience images acquired by the Scanning Electron Microscope (SEM). This is done by coupling supervised and unsupervised learning approaches. We first investigate supervised learning on a ten-category data set of images and compare the performance of the different models in terms of training accuracy. Then, we reduce the dimensionality of the features through autoencoders to perform unsupervised learning on a subset of images in a selected range of scales (from 1 m to 2 m). Finally, we compare different clustering methods to uncover intrinsic structures in the images
HRTFs Measurement Based on Periodic Sequences Robust towards Nonlinearities in Automotive Audio
The head related transfer functions (HRTFs) represent the acoustic path transfer functions between sound sources in 3D space and the listenerâs ear. They are used to create immersive audio scenarios or to subjectively evaluate sound systems according to a human-centric point of view. Cars are nowadays the most popular audio listening environment and the use of HRTFs in automotive audio has recently attracted the attention of researchers. In this context, the paper proposes a measurement method for HRTFs based on perfect or orthogonal periodic sequences. The proposed measurement method ensures robustness towards the nonlinearities that may affect the measurement system. The experimental results considering both an emulated scenario and real measurements in a controlled environment illustrate the effectiveness of the approach and compare the proposed method with other popular approaches
Gut microbiota markers in obese adolescent and adult patients: Age-dependent differential patterns
Obesity levels, especially in children, have dramatically increased over the last few decades. Recently, several studies highlighted the involvement of gut microbiota in the pathophysiology of obesity. We investigated the composition of gut microbiota in obese adolescents and adults compared to age-matched normal weight (NW) volunteers in order to assemble age- and obesity-related microbiota profiles. The composition of gut microbiota was analyzed by 16S rRNA-based metagenomics. Ecological representations of microbial communities were computed, and univariate, multivariate, and correlation analyses performed on bacterial profiles. The prediction of metagenome functional content from 16S rRNA gene surveys was carried out. Ecological analyses revealed a dissimilarity among the subgroups, and resultant microbiota profiles differed between obese adolescents and adults. Using statistical analyses, we assigned, as microbial markers, Faecalibacterium prausnitzii and Actinomyces to the microbiota of obese adolescents, and Parabacteroides, Rikenellaceae, Bacteroides caccae, Barnesiellaceae, and Oscillospira to the microbiota of NW adolescents. The predicted metabolic profiles resulted different in adolescent groups. Particularly, biosynthesis of primary bile acid and steroid acids, metabolism of fructose, mannose, galactose, butanoate, and pentose phosphate and glycolysis/gluconeogenesis were for the majority associated to obese, while biosynthesis and metabolism of glycan, biosynthesis of secondary bile acid, metabolism of steroid hormone and lipoic acid were associated to NW adolescents. Our study revealed unique features of gut microbiota in terms of ecological patterns, microbial composition and metabolism in obese patients. The assignment of novel obesity bacterial markers may open avenues for the development of patient-tailored treatments dependent on age-related microbiota profiles
Functional Significance and Predictive Value of MicroRNAs in Pediatric Obesity: Tiny Molecules with Huge Impact?
Obesity is a major health concern. While some children develop comorbidities such as insulin resistance and low-grade systemic inflammation upon weight gain, others stay metabolically healthy. There is an urgent need for clinically relevant markers with prognostic value related to disease development and intervention success. MicroRNAs (miRNAs) are established biomarkers for several disease states. Herein, we give a brief overview of miRNA biogenesis and function and the potential role of circulating miRNA in the context of pediatric obesity
Biostimulant Action of Dissolved Humic Substances From a Conventionally and an Organically Managed Soil on Nitrate Acquisition in Maize Plants
Conversion of conventional farming (CF) to organic farming (OF) is claimed to allow a sustainable management of soil resources, but information on changes induced on dissolved organic matter (DOM) are scarce. Among DOM components, dissolved humic substances (DHS) were shown to possess stimulatory effects on plant growth. DHS were isolated from CF and OF soil leacheates collected from soil monolith columns: first in November (bare soils) and then in April and June (bare and planted soils). DHS caused an enhancement of nitrate uptake rates in maize roots and modulated several genes involved in nitrogen acquisition. The DHS from OF soil exerted a stronger biostimulant action on the nitrate uptake system, but the first assimilatory step of nitrate was mainly activated by DHS derived from CF soil. To validate the physiological response of plants to DHS exposure, real-time RT-PCR analyses were performed on those genes most involved in nitrate acquisition, such as ZmNRT2.1, ZmNRT2.2, ZmMHA2 (coding for two high-affinity nitrate transporters and a PM H+-proton pump), ZmNADH:NR, ZmNADPH:NR, and ZmNiR (coding for nitrate reductases and nitrite reductase). All tested DHS fractions induced the upregulation of nitrate reductase (NR), and in particular the OF2 DHS stimulated the expression of both tested transcripts encoding for two NR isoforms. Characteristics of DHS varied during the experiment in both OF and CF soils: a decrease of high molecular weight fractions in the OF soil, a general increase in the carboxylic groups content, as well as diverse structural modifications in OF vs. CF soils were observed. These changes were accelerated in planted soils. Similarity of chemical properties of DHS with the more easily obtainable water-soluble humic substance extracted from peat (WEHS) and the correspondence of their biostimulant actions confirm the validity of studies which employ WEHS as an easily available source of DHS to investigate biostimulant actions on agricultural crops
SEI Growth and Depth Profiling on ZFO Electrodes by Soft X-Ray Absorption Spectroscopy
The evolution of the solid electrolyte interface (SEI) in carbonâcoated ZnFe2O4 (ZFOâC) anodes is studied by soft Xâray absorption spectroscopy (XAS). Experiments probe locally the SEI growth in the 2â100 nm range, using both total electron (TEY) and total fluorescence (TFY) yield techniques. XAS analysis shows that the SEI grows preferentially around the ZFOâC nanoparticles
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