10 research outputs found
Quantum measurements in fundamental physics: a user's manual
We give a systematic theoretical treatment of linear quantum detectors used
in modern high energy physics experiments, including dark matter cavity
haloscopes, gravitational wave detectors, and impulsive mechanical sensors. We
show how to derive the coupling of signals of interest to these devices, and
how to calculate noise spectra, signal-to-noise ratios, and detection
sensitivities. We emphasize the role of quantum vacuum and thermal noise in
these systems. Finally, we review ways in which advanced quantum techniques --
squeezing, non-demolition measurements, and entanglement -- can be or currently
are used to enhance these searches.Comment: 50 pages, many figures. Corrections and suggestions for new material
are welcom
Detection of high-frequency gravitational waves using high-energy pulsed lasers
We propose a new method for detecting high-frequency gravitational waves
(GWs) using high-energy pulsed lasers. Through the inverse Gertsenshtein
effect, the interaction between a GW and the laser beam results in the creation
of an electromagnetic signal. The latter can be detected using single-photon
counting techniques. We compute the minimal strain of a detectable GW which
only depends on the laser parameters. We find that a resonance occurs in this
process when the frequency of the GW is twice the frequency of the laser. With
this method, the frequency range Hz is explored
non-continuously for strains for current laser systems and
can be extended to with future generation facilities.Comment: 15 pages, 2 figures, v2 matches the published versio
Measuring Unruh radiation from accelerated electrons
Detecting thermal Unruh radiation from accelerated electrons has presented a
formidable challenge due not only to technical difficulties but also for lack
of conceptual clarity about what is actually seen by a laboratory observer. We
give a summary of the current interpretations along with a simpler heuristic
description that draws on the analogy between the Unruh effect and radiation
from a two-level atomic system. We propose an experiment to test whether there
is emission of thermal photons from an accelerated electron.Comment: 13 pages, 2 figures. This is an expanded version of section 3.2 of
arXiv:2211.13187 which we wrote for the Multi Petawatt Prioritization (MP3)
worksho
Hydro-mechanical behaviour of alkali-activated binder treated soil
An experimental investigation on the mechanical improvement induced by alkali-activated binder based on the activation of a fluidal bed combustion fly ash on a clayey soil has been developed. The use of these binders for geotechnical applications is a promising issue in terms of sustainability since it reduces the carbon footprint and allows reusing secondary by-products such as artificial pozzolans. Treated samples were prepared by mixing soil and fly ash with water and alkaline solution and dynamically compacted. Mechanical behaviour has been investigated by means of triaxial tests performed on treated samples compacted at optimum water content. Addition of alkali activated binder increased stiffness and shear strength of treated samples, whose extent depends on binder content and curing time. Macroscopic behaviour of treated soil has been linked to the experimental evidences at microscale. Microstructural analyses highlighted a high reactivity of alkali-activated fly ashes as alumino-silicate source promoting the precipitation of new mineralogical phases with cementitious properties. Amorphous alumino-silicate gels produced from alkali-activation of fly ash bound particles aggregates leading to a decrease of cumulative pore volume and porosity of treated samples and modification of the modal pore size
Clinical Assessment of Auto-positive End-expiratory Pressure by Diaphragmatic Electrical Activity during Pressure Support and Neurally Adjusted Ventilatory Assist
Background: Auto-positive end-expiratory pressure (auto-PEEP) may substantially increase the inspiratory effort during assisted mechanical ventilation. Purpose of this study was to assess whether the electrical activity of the diaphragm (EAdi) signal can be reliably used to estimate auto-PEEP in patients undergoing pressure support ventilation and neurally adjusted ventilatory assist (NAVA) and whether NAVA was beneficial in comparison with pressure support ventilation in patients affected by auto-PEEP. Methods: In 10 patients with a clinical suspicion of auto-PEEP, the authors simultaneously recorded EAdi, airway, esophageal pressure, and flow during pressure support and NAVA, whereas external PEEP was increased from 2 to 14 cm H2O. Tracings were analyzed to measure apparent "dynamic" auto-PEEP (decrease in esophageal pressure to generate inspiratory flow), auto-EAdi (EAdi value at the onset of inspiratory flow), and IDEAdi (inspiratory delay between the onset of EAdi and the inspiratory flow). Results: The pressure necessary to overcome auto-PEEP, auto-EAdi, and IDEAdi was significantly lower in NAVA as compared with pressure support ventilation, decreased with increase in external PEEP, although the effect of external PEEP was less pronounced in NAVA. Both auto-EAdi and IDEAdi were tightly correlated with auto-PEEP (r2 = 0.94 and r2 = 0.75, respectively). In the presence of auto-PEEP at lower external PEEP levels, NAVA was characterized by a characteristic shape of the airway pressure. Conclusions: In patients with auto-PEEP, NAVA, compared with pressure support ventilation, led to a decrease in the pressure necessary to overcome auto-PEEP, which could be reliably monitored by the electrical activity of the diaphragm before inspiratory flow onset (auto-EAdi)
Modifiche dei sistemi foraggeri per la zootecnia e dei sistemi di alimentazione
E\u2019 ormai pienamente acquisita la percezione dell\u2019influenza che ha il cambiamento climatico sull\u2019economia e nella societ\ue0, non solo in ragione dell\u2019aumento di intensit\ue0 e frequenza degli eventi metereologici estremi, ma anche delle politiche proposte in tutti i settori (dall\u2019industria ai trasporti, dalla sanit\ue0 alla pianificazione del territorio, e chiaramente in agricoltura e nelle relative filiere agro-alimentari) all\u2019attenzione dei diversi stakeholder. Il libro bianco intende individuare delle misure di mitigazione e di adattamento che siano integrate nei vari settori (agricoltura e zootecnia, energia, industria, trasporti, la societ\ue0 stessa) e ai vari
livelli di governo. In sintesi, il contributo multidisciplinare vuole essere un\u2019analisi dettagliata delle relazioni esistenti tra agricoltura e cambiamenti climatici, al fine di
delineare delle strategie di mitigazione ed adattamento realistiche ed attuabili
Awareness, discussion and non-prescribed use of HIV pre-exposure prophylaxis among persons living with HIV/AIDS in Italy: a Nationwide, cross-sectional study among patients on antiretrovirals and their treating HIV physicians
Background: Before Pre-Exposure Prophylaxis (PrEP) was officially recommended and made available, a few surveys among gay and bisexual men, and persons living with HIV/AIDS (PLWHA), identified an informal use of antiretrovirals (ARVs) for PrEP among HIV-negative individuals. Before PrEP availability in Italy, we aimed to assess whether PLWHA in Italy shared their ARVs with HIV-negative individuals, whether they knew people who were on PrEP, and describe the level of awareness and discussion on this preventive measure among them and people in their close circle. Methods: Two anonymous questionnaires investigating personal characteristics and PrEP awareness, knowledge, and experience were proposed to HIV specialists and their patients on ARVs in a one-week, cross-sectional survey (December 2013-January 2014). Among PLWHA, a Multivariable Logistic Regression analysis was conducted to identify factors associated with PrEP discussion with peers (close circle and/or HIV associations), and experience (use in close circle and/or personal ARV sharing). Results: Eighty-seven specialists in 31 representative Infectious Diseases departments administered the questionnaire to 1405 PLWHA. Among specialists, 98% reported awareness, 65% knew the dosage schedule, and 14% had previously suggested or prescribed PrEP. Among PLWHA, 45.6% were somehow aware, discussed or had direct or indirect experience of PrEP: 38% "had heard" of PrEP, 24% were aware of studies in HIV-negative individuals demonstrating a risk reduction through the use of ARVs, 22% had discussed PrEP, 12% with peers; 9% reported PrEP use in close circle and 1% personal ARV sharing. Factors predictive of either PrEP discussion with peers or experience differed between men and women, but across all genders were mainly related to having access to information, with HIV association membership being the strongest predictor. Conclusions: At a time and place where there were neither official information nor proposals or interventions to guide public policies on PrEP in Italy, a significant number of PLWHA were aware of it, and approximately 10% reported PrEP use in their close circle, although they rarely shared their ARVs with uninfected people for this purpose. Official policies and PrEP availability, along with implementation programs, could avoid risks from uncontrolled PrEP procurement and self-administration practices