1,352 research outputs found
Optical devices provide unprecedented insights into the laser cleaning of calcium oxalate layers
Abstract Calcium oxalates are insoluble colorless or whitish salts constituting noble patina, on both natural and artificial stone artworks' surfaces, the presence of which is extremely valued. The oxalates are not considered detrimental to the substrate, however, being often accompanied by other substances such as gypsum, silicates, and pigmented particles. They may form very adherent, relatively thick and colored layers creating disfiguring effects and hindering legibility of the pictorial surface. For this reason it may be appropriate to diminish their thickness, but patina's partial preservation is particularly required calling for extremely gradual and controllable cleaning approach. Thinning of calcium oxalate patina from a detached 16th century fresco (from Sansepolcro) was performed through the use of laser (Nd:YAG and Er:YAG) systems and chemical means (Carbogel loaded 5 wt.% of tetrasodium EDTA). Optical coherence tomography (OCT), providing a non-invasive stratigraphic cross-section of the examined surface, allowed to distinguish the oxalate from the underlying original layers and therefore to have an overview about its distribution, to numerically evaluate patina's thickness range and to provide the information on the amount of the material both removed and left on the artwork's surface. Laser scanning conoscopic microprofilometry allowed for a high-density sampling of the artwork's surface providing a three-dimensional model of the surface pattern. The obtained 3D models were used to estimate the amount of material removed and to compare them with those provided by OCT. The successful exploitation of the proposed exceptional cleaning monitoring methodology may be seen as an innovative and valid support for the restorers in the conservation of mural painting or other surfaces covered by oxalate layers and may pilot more targeted, cautious and respectful cleaning intervention
Memory beyond memory in heart beating: an efficient way to detect pathological conditions
We study the long-range correlations of heartbeat fluctuations with the
method of diffusion entropy. We show that this method of analysis yields a
scaling parameter that apparently conflicts with the direct evaluation
of the distribution of times of sojourn in states with a given heartbeat
frequency. The strength of the memory responsible for this discrepancy is given
by a parameter , which is derived from real data. The
distribution of patients in the (, )-plane yields a neat
separation of the healthy from the congestive heart failure subjects.Comment: submitted to Physical Review Letters, 5 figure
Packet loss analysis of synchronous buffer-less optical switch with shared limited range wavelength converters
Application of synchronous optical switches in Optical Packet/Burst switched networks is considered. The shared per node architectural concept, where wavelength converters are shared among all input and output channels, is applied for contention resolution in the wavelength domain. A semi-analytical traffic model suitable to represent the different contributions to packet loss is proposed and validated. Full and limited range wavelength conversion capabilities are considered, and loss results obtained to support switch design. An approximated fully analytical approach for the limited range case is also described and comparison with simulation results is presented to assess the capability to capture the main aspects of packet loss behavior. ©2007 IEEE
Performance analysis of an optical packet switch employing full/limited range share per node wavelength conversion
In this paper, we study an asynchronous optical packet switching node equipped with a number of limited range or full range wavelength converters shared per node. The packet traffic is realistically modeled by a superposition of a finite number of on-off sources as opposed to the traditional Poisson model which ignores the limited number of ports on a switch. We both study circular and non-circular limited range wavelength conversion schemes. In our simulations, we employ the far conversion policy where the optical packet is switched onto the farthest available wavelength in the tuning range, which is known to outperform the random conversion policy. We propose an approximate analytical method based on block tridiagonal Markov chains and fixed point iterations to solve for the blocking probabilities in share per node wavelength conversion systems. The method provides an accurate approximation for full range systems and acceptable results for limited range systems. © 2007 IEEE
Experimental study of greywater treatment through green walls
Among nature- based solutions (NBSs), green walls represent a key technology in the urban context because of the low energy demand and of the many ecological and social outcomes. This work presents the results of the experimental study at laboratory scale of the treatment of greywater (e.g. domestic wastewater excluding toilet flushes) through a green wall. It is made of two modular panels (1-set up for this study and 2-in use for 15 months), made of twelve pots arranged on four columns and three rows, and filled with a mix of coconut and perlite and different ornamental plant species. The green wall was fed discontinuously with 96 L/d of synthetic greywater for two months during the winter season. The treatment performances of the two panels were very high about total suspended solids (>87%), biological oxygen demand (>98%) and chemical oxygen demand (∼80%), in agreement with literature. Panel 1 exceeded the performances of panel 2 only about total suspended solids (96% vs 87%), probably because of a clogging phenomenon. This study proved the efficiency of green walls towards greywater treatment in challenging experimental conditions, as winter temperature and high hydraulic loading rate
The potential of lasmiditan in migraine
Lasmiditan, a highly selective 5-hydroxytryptamine receptor 1F (5-HT1F) agonist,
is the first drug in its class and is lacking triptan-like vasoactive properties. The US Food
and Drug Administration (FDA) has recently approved lasmiditan for the acute treatment of
migraine in adults based on positive results of two pivotal phase III trials, which showed a
significant difference to placebo in the proportion of patients achieving total migraine freedom
within 2h. More patients with lasmiditan achieved headache freedom and, in addition, freedom
from the most bothersome symptom, that is, photophobia, than with placebo. Treatmentrelated side effects seem to be related to the rapid penetration of the drug into the brain and
include dizziness, paresthesia and drowsiness, mostly of mild to moderate intensity. Interim
results from an ongoing long-term phase III trial suggest a decrease in the frequency of
adverse events after multiple lasmiditan use. Lasmiditan is a promising acute anti-migraine
therapy, in particular for patients with cardiovascular risk factors, contraindications, or
unwanted side effects to triptans
Design, status and perspective of the Mu2e crystal calorimeter
The Mu2e experiment at Fermilab will search for the charged lepton flavor
violating process of neutrino-less coherent conversion in the field
of an aluminum nucleus. Mu2e will reach a single event sensitivity of about
that corresponds to four orders of magnitude improvements
with respect to the current best limit. The detector system consists of a straw
tube tracker and a crystal calorimeter made of undoped CsI coupled with Silicon
Photomultipliers. The calorimeter was designed to be operable in a harsh
environment where about 10 krad/year will be delivered in the hottest region
and work in presence of 1 T magnetic field. The calorimeter role is to perform
/e separation to suppress cosmic muons mimiking the signal, while
providing a high level trigger and a seeding the track search in the tracker.
In this paper we present the calorimeter design and the latest RD results.Comment: 4 pages, conference proceeding for a presentation held at TIPP'2017.
To be published on Springer Proceedings in Physic
Quality Assurance on a custom SiPMs array for the Mu2e experiment
The Mu2e experiment at Fermilab will search for the coherent
conversion on aluminum atoms. The detector system consists of a straw tube
tracker and a crystal calorimeter. A pre-production of 150 Silicon
Photomultiplier arrays for the Mu2e calorimeter has been procured. A detailed
quality assur- ance has been carried out on each SiPM for the determination of
its own operation voltage, gain, dark current and PDE. The measurement of the
mean-time-to-failure for a small random sample of the pro-production group has
been also completed as well as the determination of the dark current increase
as a function of the ioninizing and non-ioninizing dose.Comment: 4 pages, 10 figures, conference proceeding for NSS-MIC 201
Impact of fatigue on health- related quality of life and illness perception in a monocentric cohort of patients with systemic lupus erythematosus.
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