426 research outputs found
EVS: Head-up or Head Down? Evaluation of Crew Procedure and Human Factors for Enhanced Vision Systems
Feasibility of an EVS head-down procedure is examined that may provide the same operational benefits under low visibility as the FAA rule on Enhanced Flight Visibility that requires the use of a head-up display (HUD). The main element of the described EVS head-down procedure is the crew procedure within cockpit for flying the approach. The task sharing between Pilot-Flying and Pilot-Not-Flying is arranged such that multiple head-up/head-down transitions can be avoided. The pilot-flying is using the head-down display for acquisition of the necessary visual cues in the EVS image. The pilot-not-flying is monitoring the instruments and looking for the outside visual cues
Neural Substrates of Chronic Pain in the Thalamocortical Circuit
Chronic pain (CP), a pathological condition with a large repertory of signs and symptoms, has no recognizable neural functional common hallmark shared by its diverse expressions. The aim of the present research was to identify potential dynamic markers shared in CP models, by using simultaneous electrophysiological extracellular recordings from the rat ventrobasal thalamus and the primary somatosensory cortex. We have been able to extract a neural signature attributable solely to CP, independent from of the originating conditions. This study showed disrupted functional connectivity and increased redundancy in firing patterns in CP models versus controls, and interpreted these signs as a neural signature of CP. In a clinical perspective, we envisage CP as disconnection syndrome and hypothesize potential novel therapeutic appraisal
Probing for local activity-related modulation of the infrared backscattering of the brain cortex
The possibility to measure the metabolic activity of the brain cortex, with submillimeter spatial and subsecond temporal resolution, would open up enticing scenarios in addressing basic issues on the relation between different structural components of brain signal processing, and in providing an operational pathway to interaction with (dis)functional signal patterns. In the present article, we report the description of a simple system that allows the detection of the minute changes that occur in the optical backscattering of the cortex as a metabolic response to external stimuli. The simplicity of the system is compatible with scalability to an implantable probe. We validate the system on an animal model, and we propose an algorithm to extract meaningful data from the measured signal. We thus show the detection of individual haemodynamic cortical responses to individual stimulation events, and we provide operational considerations on the signal structure
Quantum density matrix theory for a laser without adiabatic elimination of the population inversion: transition to lasing in the class-B limit
Despite the enormous technological interest in micro and nanolasers,
surprisingly, no class-B quantum density-matrix model is available to date,
capable of accurately describing coherence and photon correlations within a
unified theory. In class-B lasers applicable for most solid-state lasers at
room temperature, the macroscopic polarization decay rate is larger than the
cavity damping rate which, in turn, exceeds the upper level population decay
rate. Here we carry out a density-matrix theoretical approach for generic
class-B lasers, and provide closed equations for the photonic and atomic
reduced density matrix in the Fock basis of photons. Such a relatively simple
model can be numerically integrated in a straightforward way, and exhibits all
the expected phenomena, from one-atom photon antibunching, to the well-known
S-shaped input-output laser emission and super-Poissonian autocorrelation for
many atoms (), and from few photons (large spontaneous
emission factors, ) to the thermodynamic limit ( and
). Based on the analysis of , we conclude that
super-Poissonian fluctuations are clearly related to relaxation oscillations in
the photon number. We predict a strong damping of relaxation oscillations with
an atom number as small as . This model enables the study of
few-photon bifurcations and non-classical photon correlations in class-B laser
devices, also leveraging quantum descriptions of coherently coupled nanolaser
arrays.Comment: 23 pages, 6 figure
Extraction and Characterization of Essential Discharge Patterns from Multisite Recordings of Spiking Ongoing Activity
Conditional sampling, in comparison with the classical constant time-bin sampling, enables to reject, at least in most cases, the common mode modulation of the spiking frequency across different spiking sources. Here we consider a simple but significant example while a more general analysis is currently in preparation: Consider two spiking neurons and let n1, n2 the number of spikes emitted in a time period T. They both follow a Poisson process with parameters λcλ1T and λcλ2T respectively, being λc a common modulation term, λ1 and λ2 the independent component of their activity. Let n1 + n2 = k and Pn1,n2 = Pn1,k−n1 the probability of observing n1 and k − n1 spikes (respectively from the first and the second neuron) in a period T. Then Pn1,k−n1 = e−λcT (λ1+λ2) (T λc) k λn 1 1 λk−n 1 2 n1!(k−n1)! Now consider the conditional probability of observing n1 and k − n1 spikes i
Applicability of an orthogonal cutting slip-line field model for the microscale
Mechanical micromachining is a very flexible and widely exploited process, but its knowledge should still be improved
since several incompletely explained phenomena affect the microscale chip removal. Several models have been developed
to describe the machining process, but only some of them consider a rounded edge tool, which is a typical condition in
micromachining. Among these models, the Waldorf’s slip-line field model for the macroscale allows to separately evaluate
shearing and ploughing force components in orthogonal cutting conditions; therefore, it is suitable to predict cutting
forces when a large ploughing action occurs, as in micromachining. This study aims at demonstrating how this model is
suitable also for micromachining conditions. To achieve this goal, a clear and repeatable procedure has been developed
for objectively validating its force prediction performance at low uncut chip thickness (less than 50 mm) and relatively
higher cutting edge radius. The proposed procedure makes the model generally applicable after a suitable and nonextensive
calibration campaign. This article shows how calibration experiments can be selected among the available cutting
trial database based on the model force prediction capability. Final validation experiments have been used to show
how the model is robust to a cutting speed variation even if the cutting speed is not among the model quantities. A suitable
set-up, especially designed for microturning conditions, has been used to measure forces and chip thickness. Tests
have been performed on 6082-T6 Aluminum alloy with different cutting speeds and different ratios between uncut chip
thickness and cutting edge radius
Optimization of a 3D dynamic culturing system for in vitro modeling of Frontotemporal Neurodegeneration-relevant pathologic features
Frontotemporal lobar degeneration (FTLD) is a severe neurodegenerative disorder that is diagnosed with increasing frequency in clinical setting. Currently, no therapy is available and in addition the molecular basis of the disease are far from being elucidated. Consequently, it is of pivotal importance to develop reliable and cost-effective in vitro models for basic research purposes and drug screening. To this respect, recent results in the field of Alzheimer’s disease have suggested that a tridimensional (3D) environment is an added value to better model key pathologic features of the disease. Here, we have tried to add complexity to the 3D cell culturing concept by using a microfluidic bioreactor, where cells are cultured under a continuous flow of medium, thus mimicking the interstitial fluid movement that actually perfuses the body tissues, including the brain. We have implemented this model using a neuronal-like cell line (SH-SY5Y), a widely exploited cell model for neurodegenerative disorders that shows some basic features relevant for FTLD modeling, such as the release of the FTLD-related protein progranulin (PRGN) in specific vesicles (exosomes). We have efficiently seeded the cells on 3D scaffolds, optimized a disease-relevant oxidative stress experiment (by targeting mitochondrial function that is one of the possible FTLD-involved pathological mechanisms) and evaluated cell metabolic activity in dynamic culture in comparison to static conditions, finding that SH-SY5Y cells cultured in 3D scaffold are susceptible to the oxidative damage triggered by a mitochondrial-targeting toxin (6-OHDA) and that the same cells cultured in dynamic conditions kept their basic capacity to secrete PRGN in exosomes once recovered from the bioreactor and plated in standard 2D conditions. We think that a further improvement of our microfluidic system may help in providing a full device where assessing basic FTLD-related features (including PRGN dynamic secretion) that may be useful for monitoring disease progression over time or evaluating therapeutic interventions
All that meets the eye: the contribution of reward processing and pupil mimicry on pupillary reactions to facial trustworthiness
The present work investigates pupillary reactions induced by exposure to faces with different levels of trustworthiness. Participants' (N = 69) pupillary changes were recorded while they viewed white male faces with a neutral expression varying on facial trustworthiness. Results suggest that reward processing and pupil mimicry are relevant mechanisms driving participants' pupil reactions. However, when including both factors in one statistical model, pupil mimicry seems to be a stronger predictor than reward processing of participants' pupil dilation. Results are discussed in light of pupillometry evidence.Action Contro
Caratterizzazione della risposta sismica nella città di Benevento.
L'ampiezzà de1 moto del suolo, ed il suo contenuto in frequenza, alla súpeúcie
della TerIa dÃpede dale caratte stiche della, sorgente sismica e dalle
proprietà meccaniche del úezzo in cui si propagano le onde sismiche. In pa.rtico
lare, gli strati pmssimi alla superficie possono modifrcare in modo sigdficativo
il segnale sismlco. InJatti la presenza, di uno strato con un fo e contraato di im
pedenza, spetto ad un basarnento sottostà nte prÌò indurc etretti di risonanza
alterando sensibilmente il livelo di anpiezza, il conterùto in Îrequenza e la, durata
delle oscilla.zioni del suolo. Un esempio estîemo di questo fenomeno è stato
evidenziatoi n occasiored el terremoto di Michoacan,M essico,d el 1985.Q uesto
evento, pur essendo a-r.venuto ad alcune centinaia di chilometri da.lla capitale,
ha, eccitato con il pe.iodo proprio di oscillnzioÈe( cilca 2 secondi)i depositi di
riempimento di un antico lago prosciugato, su cui è costruita parte di Città , del
Messico, pmvocaùdo iI crollo di nurerosi edifici e misliaia di morti (Singh et
al., 198
Knowledge and attitude of parents or caretakers regarding transmissibility os caries disease
Dental caries is a transmissible infectious disease in which mutans streptococci are generally considered to be the main etiological agents. Although the transmissibility of dental caries is relatively well established in the literature, little is known whether information regarding this issue is correctly provided to the population. The present study aimed at evaluating, by means of a questionnaire, the knowledge and usual attitude of 640 parents and caretakers regarding the transmissibility of caries disease. Most interviewed adults did not know the concept of dental caries being an infectious and transmissible disease, and reported the habit of blowing and tasting food, sharing utensils and kissing the children on their mouth. 372 (58.1%) adults reported that their children had already been seen by a dentist, 264 (41.3%) answered that their children had never gone to a dentist, and 4 (0.6%) did not know. When the adults were asked whether their children had already had dental caries, 107 (16.7%) answered yes, 489 (76.4%) answered no, and 44 (6.9%) did not know. Taken together, these data reinforce the need to provide the population with some important information regarding the transmission of dental caries in order to facilitate a more comprehensive approach towards the prevention of the disease
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