A neural network ensemble approach for GDP forecasting

We propose an ensemble learning methodology to forecast the future US GDP growth release. Our approach combines a Recurrent Neural Network (RNN) with a Dynamic Factor model accounting for time-variation in mean with a General- ized Autoregressive Score (DFM-GAS). The analysis is based on a set of predictors encompassing a wide range of variables measured at different frequencies. The forecast exercise is aimed at evaluating the predictive ability of each model's com- ponent of the ensemble by considering variations in mean, potentially caused by recessions affecting the economy. Thus, we show how the combination of RNN and DFM-GAS improves forecasts of the US GDP growth rate in the aftermath of the 2008-09 global financial crisis. We find that a neural network ensemble markedly reduces the root mean squared error for the short-term forecast horizon

More than skin-deep: integration of skin-based and musculo-skeletal reference frames in localisation of touch

The skin of the forearm is, in one sense, a flat 2D sheet, but in another sense approximately cylindrical, mirroring the 3D volumetric shape of the arm. The role of frames of reference based on the skin as a 2D sheet versus based on the musculo-skeletal structure of the arm remains unclear. When we rotate the forearm from a pronated to a supinated posture, the skin on its surface is displaced. Thus, a marked location will slide with the skin across the underlying flesh, and the touch perceived at this location should follow this displacement if it is localised within a skin-based reference frame. We investigated, however, if the perceived tactile locations were also affected by the rearrangement in underlying musculo-skeletal structure, i.e. displaced medially and laterally on a pronated and supinated forearm, respectively. Participants pointed to perceived touches (Experiment 1), or marked them on a three-dimensional size-matched forearm on a computer screen (Experiment 2). The perceived locations were indeed displaced medially after forearm pronation in both response modalities. This misperception was reduced (Experiment 1), or absent altogether (Experiment 2) in the supinated posture when the actual stimulus grid moved laterally with the displaced skin. The grid was perceptually stretched at medial-lateral axis, and it was displaced distally, which suggest the influence of skin-based factors. Our study extends the tactile localisation literature focused on the skin-based reference frame and on the effects of spatial positions of body parts by implicating the musculo-skeletal factors in localisation of touch on the body

A simplified edge illumination set-up for quantitative phase contrast mammography with synchrotron radiation at clinical doses

This work presents the first study of x-ray phase contrast imaging based on a simple implementation of the edge illumination method (EIXPCi) in the field of mammography with synchrotron radiation. A simplified EIXPCi set-up was utilized to study a possible application in mammography at clinical doses. Moreover, through a novel algorithm capable of separating and quantifying absorption and phase perturbations of images acquired in EIXPCi modality, it is possible to extract quantitative information on breast images, allowing an accurate tissue identification. The study was carried out at the SYRMEP beamline of Elettra synchrotron radiation facility (Trieste, Italy), where a mastectomy specimen was investigated with the EIXPCi technique. The sample was exposed at three different energies suitable for mammography with synchrotron radiation in order to test the validity of the novel algorithm in extracting values of linear attenuation coefficients integrated over the sample thickness. It is demonstrated that the quantitative data are in good agreement with the theoretical values of linear attenuation coefficients calculated on the hypothesis of the breast with a given composition. The results are promising and encourage the current efforts to apply the method in mammography with synchrotron radiation

Fingers hold spatial information that toes do not

Fingers have preferential associations with relative spatial locations. Tactile localisation is faster when the fingers are in these locations, such as when the index finger is in a relatively higher spatial position, and the thumb in a relatively lower position. However, it is unclear whether these associations are related to hands specifically, or are a more general characteristic of limbs. The present study therefore investigated whether toes have similar spatial associations. If these associations reflect the statistics of natural limb usage, very different patterns of association would be expected for the fingers and toes, given their different functional roles in daily behaviour. We measured reaction time (RT) and error rates of responses to tactile stimuli applied to the middle finger/toe or thumb/big toe, when they were positioned in a relative upper or lower location. We replicated the finding that fingers have preferential associations that facilitates localisation – RT and error rate were lower when the index finger was in the top position, and the thumb in the bottom position. We found that toes do not hold the same spatial information, though it remains unclear whether toes hold different spatial information or none at all. These results demonstrate spatial information held by the fingers is stronger and more reliable than for the toes, so is not a general characteristic of limbs, but possibly related to hand use

Methylene blue MMX® tablets for chromoendoscopy. Bioavailability, colon staining and safety in healthy volunteers undergoing a full colonoscopy.

Abstract Methylene blue-MMX® tablets are proposed as an aid for detection and visualisation of adenomas and carcinomas in patients undergoing colonoscopy, by improving their detection rate and highlighting the presence of the intestinal dysplastic lesions. Single total doses of 100 and 200 mg were administered to healthy volunteers undergoing a bowel cleansing preparation and a full colonoscopy to investigate the colonic staining. The pharmacokinetics of methylene blue and the safety after exposure to the tablets were also investigated. With 200 mg, the best staining, assessed as the sum of acceptable and good staining, was achieved in the ascending colon and rectosigmoid (75% subjects each), the transverse and the descending colon (approximately 63% each). Absence of staining or overstaining were reported for no colonic region of interest in any subject. Similar results were observed in the 100 mg dose group. Methylene blue blood concentrations reached a peak (Cmax) in a median time (Tmax) of 12 h with 100 mg and 16 h with 200 mg. AUC0-t was 10.7 ± 6.7 μg/mLxh after 100 mg and 25.2 ± 7.4 μg/mLxh after 200 mg. Half-life ranged between 9 and 22 h after the lower dose and between 6 and 26 h after the higher dose. The cumulative urinary excretion was about 28% after 100 mg and about 39% after 200 mg up to 60 h post-dose. The overall frequency of adverse events after single dose of the test product administered along with a bowel cleansing preparation was 39%, but only one was related to the test product: abnormal transaminases. The most frequent adverse event was a transient polyuria (17%). One serious adverse event (gastrointestinal haemorrhage) led the subject to study discontinuation and hospitalisation and another subject withdrew the study due to one adverse event (haematemesis). Either event was not related to methylene blue