Treatment of Vascular Dementia: The Route of Prevention

Vascular dementia (VaD), rather than being considered as a univocal nosological entity, should be regarded as a heterogeneous clinical entity which differs in clinical-pathological phenotype as well as in pathophysiological mechanisms, but shares cerebrovascular disease (CVD), resulting from vascular or circulatory pathology, as the cause of dementia. The aim of this review is to discuss VaD treatment focusing particularly on more prevalent ischemic forms. Due to the fact that there are presently no treatments capable of obtaining considerable results once VaD is clinically established, specific emphasis will be given to the therapeutic strategies aimed at the prevention of CVD risk factors. The therapeutic strategies aimed at slowing the progression of the disease will also be discussed

Is idiopathic intracranial hypertension without papilledema a risk factor for migraine progression?

The association of chronic migraine (CM) with an idiopathic intracranial hypertension without papilledema (IIHWOP), although much more prevalent than expected in clinical series of CM sufferers, is not included among the risk factors for migraine progression. We discuss the available evidence supporting the existence of a pathogenetic link between CM and idiopathic intracranial hypertensive disorders and suggest a causative role for IIHWOP in migraine progression

Continuous data assimilation for global numerical weather prediction

A new configuration of the European Centre for Medium-Range Weather Forecasts (ECMWF) incremental 4D-Var data assimilation (DA) system is introduced which builds upon the quasi-continuous DA concept proposed in the mid-1990s. Rather than working with a fixed set of observations, the new 4D-Var configuration exploits the near-continuous stream of incoming observations by introducing recently arrived observations at each outer loop iteration of the assimilation. This allows the analysis to benefit from more recent observations. Additionally, by decoupling the start time of the DA calculations from the observational data cut-off time, real-time forecasting applications can benefit from more expensive analysis configurations that previously could not have been considered. In this work we present results of a systematic comparison of the performance of a Continuous DA system against that of two more traditional baseline 4D-Var configurations. We show that the quality of the analysis produced by the new, more continuous configuration is comparable to that of a conventional baseline that has access to all of the observations in each of the outer loops, which is a configuration not feasible in real-time operational numerical weather prediction. For real-time forecasting applications, the Continuous DA framework allows configurations which clearly outperform the best available affordable non-continuous configuration. Continuous DA became operational at ECMWF in June 2019 and led to significant 2 to 3% reductions in medium-range forecast root mean square errors, which is roughly equivalent to 2-3 hr of additional predictive skill.Peer reviewe

Spectral estimates for saddle point matrices arising in weak constraint four-dimensional variational data assimilation

We consider the large-sparse symmetric linear systems of equations that arise in the solution of weak constraint four-dimensional variational data assimilation, a method of high interest for numerical weather prediction. These systems can be written as saddle point systems with a $3 \times 3$ block structure but block eliminations can be performed to reduce them to saddle point systems with a $2 \times 2$ block structure, or further to symmetric positive definite systems. In this paper, we analyse how sensitive the spectra of these matrices are to the number of observations of the underlying dynamical system. We also obtain bounds on the eigenvalues of the matrices. Numerical experiments are used to confirm the theoretical analysis and bounds

Discovery of a probable 4-5 Jupiter-mass exoplanet to HD 95086 by direct-imaging

Direct imaging has just started the inventory of the population of gas giant planets on wide-orbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. We report here the discovery in L' (3.8 microns) images of a probable companion orbiting at 56 AU the young (10-17 Myr), dusty, and early-type (A8) star HD 95086. This discovery is based on observations with more than a year-time-lapse. Our first epoch clearly revealed the source at 10 sigma while our second epoch lacked good observing conditions hence yielding a 3 sigma detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests the companion to be comoving with the star, with a 3 sigma confidence level. The planetary nature of the source is reinforced by a non-detection in Ks-band (2.18 microns) images according to its possible extremely red Ks - L' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4-5MJup (at 10-17 Myr) using "hot-start" evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star.Comment: accepted for publication to APJ

AF Lep b: the lowest mass planet detected coupling astrometric and direct imaging data

Aims. Using the direct imaging technique we searched for low mass companions around the star AF Lep that presents a significant proper motion anomaly (PMa) signal obtained from the comparison of Hipparcos and Gaia eDR3 catalogs. Methods. We observed AF Lep in two epochs with VLT/SPHERE using its subsystems IFS and IRDIS in the near-infrared (NIR) covering wavelengths ranging from the Y to the K spectral bands (between 0.95 and 2.3 {\mu}m). The data were then reduced using the high-contrast imaging techniques angular differential imaging (ADI) and spectral differential imaging (SDI) to be able to retrieve the signal from low mass companions of the star. Results. A faint companion was retrieved at a separation of ~0.335" from the star and with a position angle of ~70.5 deg in the first epoch and with a similar position in the second epoch. This corresponds to a projected separation of ~9 au. The extracted photometry allowed us to estimate for the companion a mass between 2 and 5 MJup. This mass is in good agreement with what is expected for the dynamic mass of the companion deduced using astrometric measures (5.2-5.5 MJup). This is the first companion with a mass well below the deuterium burning limit discovered coupling direct imaging with PMa measures. Orbit fitting done using the orvara tool allowed to further confirm the companion mass and to define its main orbital parameters.Comment: 10 pages, 8 Figures, accepted for publication on A&

Right phrenic nerve palsy following transcatheter radiofrequency current atrial fibrillation ablation: Case report

Phrenic nerve palsy (PNP) is a well-known complication of cardiac surgery or jugular/subclavian vein catheterization, presenting with cough, hiccups, dyspnoea/shortness of breath and, in some cases, ventilatory failure. Rarely, PNP is a complication of transcatheter radiofrequency ablation for atrial fibrillation. This report describes the case of a 72-year-old woman with a 2-year history of recurrent paroxysmal atrial fibrillation associated with occasional palpitations and shortness of breath who underwent routine transcatheter radiofrequency ablation. Three days after the procedure, the patient developed shortness of breath and progressive dyspnoea. Motor nerve conduction showed the absence of the right phrenic nerve compound motor action potential compared with the normal left side confirming the diagnosis of a right phrenic nerve palsy. This current case demonstrated the importance of undertaking an electrophysiological evaluation of phrenic nerve conduction after transcatheter radiofrequency ablation in patients presenting with palpitations and shortness of breath even if present a few days after the procedure

A new white dwarf companion to the Δμ\Delta\mu star GJ 3346

We present the discovery of a white dwarf companion at 3.6" from GJ3346, a nearby ($\pi\sim$42 mas) K star observed with SPHERE@VLT as part of an open time survey for faint companions to objects with significant proper motion discrepancies ($\Delta\mu$) between Gaia DR1 and Tycho-2. Syrius-like systems like GJ3346AB, which include a main sequence star and a white dwarf, can be difficult to detect because of the intrinsic faintness of the latter. They have, however, been found to be common contaminants for direct imaging searches. White dwarfs have in fact similar brightness to sub-stellar companions in the infrared, while being much brighter in the visible bands like those used by Gaia. Combining our observations with Gaia DR2 and with several additional archival data sets, we were able to fully constrain the physical properties of GJ3346B, such as its effective temperature (11$\times$10$^3\pm$500 K) as well as the cooling age of the system (648$\pm$58 Myrs). This allowed us to better understand the system history and to partially explains the discrepancies previously noted in the age indicators for this objects. Although further investigation is still needed, it seems that GJ3346, which was previously classified as young, is in fact most likely to be older than 4 Gyrs. Finally, given that the mass (0.58$\pm$0.01$M_{\odot}$)} and separation (85 au) of GJ3346B are compatible with the observed $\Delta\mu$, this discovery represents a further confirmation of the potential of this kind of dynamical signatures as selection methods for direct imaging surveys targeting faint, sub-stellar companions.Comment: 10 pages, 7 figure

The structural connectome constrains fast brain dynamics

Brain activity during rest displays complex, rapidly evolving patterns in space and time. Structural connections comprising the human connectome are hypothesized to impose constraints on the dynamics of this activity. Here, we use magnetoencephalography (MEG) to quantify the extent to which fast neural dynamics in the human brain are constrained by structural connections inferred from diffusion MRI tractography. We characterize the spatio-temporal unfolding of whole-brain activity at the millisecond scale from source-reconstructed MEG data, estimating the probability that any two brain regions will significantly deviate from baseline activity in consecutive time epochs. We find that the structural connectome relates to, and likely affects, the rapid spreading of neuronal avalanches, evidenced by a significant association between these transition probabilities and structural connectivity strengths (r = 0.37, p<0.0001). This finding opens new avenues to study the relationship between brain structure and neural dynamics