Forecasting Government Bond Yields with Large Bayesian VARs

We propose a new approach to forecasting the term structure of interest rates, which allows to efficiently extract the information contained in a large panel of yields. In particular, we use a large Bayesian Vector Autoregression (BVAR) with an optimal amount of shrinkage towards univariate AR models. Focusing on the U.S., we provide an extensive study on the forecasting performance of our proposed model relative to most of the existing alternative speci.cations. While most of the existing evidence focuses on statistical measures of forecast accuracy, we also evaluate the performance of the alternative forecasts when used within trading schemes or as a basis for portfolio allocation. We extensively check the robustness of our results via subsample analysis and via a data based Monte Carlo simulation. We .nd that: i) our proposed BVAR approach produces forecasts systematically more accurate than the random walk forecasts, though the gains are small; ii) some models beat the BVAR for a few selected maturities and forecast horizons, but they perform much worse than the BVAR in the remaining cases; iii) predictive gains with respect to the random walk have decreased over time; iv) di¤erent loss functions (i.e., "statistical" vs "economic") lead to di¤erent ranking of speci.c models; v) modelling time variation in term premia is important and useful for forecasting.Bayesian methods, Forecasting, Term Structure.

Forecasting Exchange Rates with a Large Bayesian VAR

Models based on economic theory have serious problems at forecasting exchange rates better than simple univariate driftless random walk models, especially at short horizons. Multivariate time series models suffer from the same problem. In this paper, we propose to forecast exchange rates with a large Bayesian VAR (BVAR), using a panel of 33 exchange rates vis-a-vis the US Dollar. Since exchange rates tend to co-move, the use of a large set of them can contain useful information for forecasting. In addition, we adopt a driftless random walk prior, so that cross-dynamics matter for forecasting only if there is strong evidence of them in the data. We produce forecasts for all the 33 exchange rates in the panel, and show that our model produces systematically better forecasts than a random walk for most of the countries, and at any forecast horizon, including at 1-step ahead.Exchange Rates, Forecasting, Bayesian VAR

Studying Axon-Astrocyte Functional Interactions by 3D Two-Photon Ca²⁺ Imaging: A Practical Guide to Experiments and "Big Data" Analysis.

Recent advances in fast volumetric imaging have enabled rapid generation of large amounts of multi-dimensional functional data. While many computer frameworks exist for data storage and analysis of the multi-gigabyte Ca <sup>2+</sup> imaging experiments in neurons, they are less useful for analyzing Ca <sup>2+</sup> dynamics in astrocytes, where transients do not follow a predictable spatio-temporal distribution pattern. In this manuscript, we provide a detailed protocol and commentary for recording and analyzing three-dimensional (3D) Ca <sup>2+</sup> transients through time in GCaMP6f-expressing astrocytes of adult brain slices in response to axonal stimulation, using our recently developed tools to perform interactive exploration, filtering, and time-correlation analysis of the transients. In addition to the protocol, we release our in-house software tools and discuss parameters pertinent to conducting axonal stimulation/response experiments across various brain regions and conditions. Our software tools are available from the Volterra Lab webpage at https://wwwfbm.unil.ch/dnf/group/glia-an-active-synaptic-partner/member/volterra-andrea-volterra in the form of software plugins for Image J (NIH)-a de facto standard in scientific image analysis. Three programs are available: <i>MultiROI_TZ_profiler</i> for interactive graphing of several movable ROIs simultaneously, <i>Gaussian_Filter5D</i> for Gaussian filtering in several dimensions, and <i>Correlation_Calculator</i> for computing various cross-correlation parameters on voxel collections through time

Fast COVID-19 vaccine effectiveness estimation on the basis of recovered individual propensity to be vaccinated

The main purpose of this article is to point out to the CDCs of the various governments, as well as to independent agencies and press offices, the need and advantages of correcting incidence data of the infection, as well as to propose a practical equation to calculate vaccine effectiveness, based on the count of recovered subjects who have not yet been vaccinated. This equation can be used to accompany data on infection incidence aimed at the general public, as well as an “easy-to-access” formula to be used for the official and institutional communication of the CDCs

ICTOGENESI ED EPILETTOGENESI IN UN MODELLO DI EPILESSIA DEL LOBO TEMPORALE

ABSTRACT Temporal lobe epilepsy (TLE) is the most common partial epilepsy and it is often associated with pharmacoresistance. Surgery has become the standard of care for patients with intractable temporal lobe epilepsy, Pre-surgical analyses with intracranial electrode to identify the epileptic focus reveal the presence of a characteristic high frequency low voltage activity at seizure onset. Previous work in our laboratory demonstrated that this pattern is reproducible in the model of guinea pig isolated brain perfused with bicucullin and pilocarpine (Uva et al., 2005; 2008). Intracellular recording during seizure onset reveal an intense activation of GABAergic neuron while principal cell are silent in medial entorinal cortex (Gnatkovsky et al., 2008). To confirm that ictogenesis pattern is a network property independent from the substance used to induce seizure we perfused a potassium channel blocker, 4AP, in the guinea pig brain. Furthermore, in vivo study injecting Kainic acid in the right hippocampus in anesthetized and freely moving guinea pig in acute and chronic period was performed. Both in vitro and in vivo study confirmed the presence of high frequency and low voltage signal

Taste intensity and hedonic responses to simple beverages in gastrointestinal cancer patients

Changes in the taste of food have been implicated as a potential cause of reduced dietary intake among cancer patients. However, data on intensity and hedonic responses to the four basic tastes in cancer are scanty and contradictory. The present study aimed at evaluating taste intensity and hedonic responses to simple beverages in 47 anorectic patients affected by gastrointestinal cancer and in 55 healthy subjects. Five suprathreshold concentrations of each of the four test substances (sucrose in black current drinks, citric acid in lemonade, NaCl in unsalted tomato juice, and urea in tonic water) were used. Patients were invited to express a judgment of intensity and pleasantness ranging from 0 to 10. Mean intensity scores directly correlated with concentrations of sour, salty, bitter, and sweet stimuli, in both normals and those with cancer. Intensity judgments were higher in cancer patients with respect to sweet (for median and high concentrations, P < 0.05), salty (for all concentrations, P < 0.05), and bitter tastes (for median concentration, P < 0.01). Hedonic function increased with the increase of the stimuli only for the sweet taste. A negative linear correlation was found between sour, bitter, and salty concentrations and hedonic score. Both in cancer patients and in healthy subjects, hedonic judgments increased with the increase of the stimulus for the sweet taste (r 1/4 0.978 and r 1/4 0.985, P 1/4 0.004 and P 1/4 0.002, respectively), and decreased for the salty (r 1/4 ??0.827 and r 1/4 ??0.884, P 1/4 0.084 and P 1/4 0.047, respectively) and bitter tastes (r 1/4 ??0.990 and r 1/4 ??0.962, P 1/4 0.009 and P 1/4 0.001, respectively). For the sour taste, the hedonic scores remained stable with the increase of the stimulus in noncancer controls (r 1/4 ??0.785, P 1/4 0.115) and decreased in cancer patients (r 1/4 ??0.996, P 1/4 0.0001). The hedonic scores for the sweet taste and the bitter taste were similar in cancer patients and healthy subjects, and these scores were significantly higher in cancer patients than in healthy subjects for most of the concentrations of the salty taste and all the concentrations of the sour taste. The present study suggests that cancer patients, compared to healthy individuals, have a normal sensitivity, a normal likingfor pleasant stimuli, and a decreased dislike for unpleasant stimuli. Moreover, when compared to controls, they show higher hedonic scores for middle and high concentrations of the salty taste and for all concentrations of the sour taste. Further studies are needed to evaluate whether these changes observed in cancer patients translate into any alteration in dietary behavior and/or food preferences

Resource Control for Synchronous Cooperative Threads

We develop new methods to statically bound the resources needed for the execution of systems of concurrent, interactive threads. Our study is concerned with a \emph{synchronous} model of interaction based on cooperative threads whose execution proceeds in synchronous rounds called instants. Our contribution is a system of compositional static analyses to guarantee that each instant terminates and to bound the size of the values computed by the system as a function of the size of its parameters at the beginning of the instant. Our method generalises an approach designed for first-order functional languages that relies on a combination of standard termination techniques for term rewriting systems and an analysis of the size of the computed values based on the notion of quasi-interpretation. We show that these two methods can be combined to obtain an explicit polynomial bound on the resources needed for the execution of the system during an instant. As a second contribution, we introduce a virtual machine and a related bytecode thus producing a precise description of the resources needed for the execution of a system. In this context, we present a suitable control flow analysis that allows to formulte the static analyses for resource control at byte code level

Preliminary experiences with contact endoscopy of the larynx

Nine patients with laryngeal polyps, four with Reinke’s edema, three with leukoplakia, one with papilloma and one with malignant tumor were studied by means of laryngeal contact endoscopy during microlaryngoscopy. This technique allowed in vivo and in situ visualization of the superficial layer of the laryngeal epithelium after staining with methylene blue. Cell structures evaluated were the size and color of the nuclei, the nucleus/cytoplasm ratio, nuclear and cytoplasmic contours, the presence of nucleoli, mitoses and keratoses, as well as the microvascular network of the mucosa and superficial cellular changes from normal to pathological. The normal squamous epithelium of the vocal cord showed a homogeneous cellular population with regular nuclear and cytoplasmic morphological characteristics and a uniform nucleus-to-cytolasm ratio. Specific cellular epithelial pat- terns and several alterations of the vascular distribution were found in different pathological conditions. Cytological pictures obtained at contact endoscopy were consistent with histological findings in all the patients studie

Three-dimensional Ca2+ imaging advances understanding of astrocyte biology.

Astrocyte communication is typically studied by two-dimensional calcium ion (Ca2+) imaging, but this method has not yielded conclusive data on the role of astrocytes in synaptic and vascular function. We developed a three-dimensional two-photon imaging approach and studied Ca2+ dynamics in entire astrocyte volumes, including during axon-astrocyte interactions. In both awake mice and brain slices, we found that Ca2+ activity in an individual astrocyte is scattered throughout the cell, largely compartmented between regions, preponderantly local within regions, and heterogeneously distributed regionally and locally. Processes and endfeet displayed frequent fast activity, whereas the soma was infrequently active. In awake mice, activity was higher than in brain slices, particularly in endfeet and processes, and displayed occasional multifocal cellwide events. Astrocytes responded locally to minimal axonal firing with time-correlated Ca2+ spots