1,747 research outputs found
Aerosol direct radiative effect in the Po Valley region derived from AERONET measurements
International audienceThe aerosol direct radiative effect (ADRE) affecting the Po Valley and the adjacent North Adriatic Sea is studied using 10-year series of measurements collected at two AERONET sites located in the western part of the Valley (Ispra), and on a platform (AAOT) offshore Venice. This region is characterized by a high, mostly continental, aerosol load with comparable average aerosol optical thickness ?a at both locations (0.21 at 500 nm) and more absorbing aerosols at Ispra. A dynamic aerosol model accounting for the changes in scattering phase function with ?a is used for radiative transfer calculations, together with boundary conditions representative of terrestrial and marine surfaces. A sensitivity analysis allows the construction of an error budget for the daily ADRE estimates, found to be of the order of 20% and mostly due to uncertainties on aerosol single scattering albedo and ?a. The daily radiative efficiencies, normalized by ?a at 500 nm, increase from December to June, from ?17 to ?24 W m?2 ?a?1 at top-of-atmosphere (TOA) and ?33 to ?72 W m?2 ?a?1 at surface for the Po Valley, and from ?15 to ?32 (TOA) and ?35 to ?65 W m?2 ?a?1 (surface) for the AAOT site. The average of log-transformed ADRE for TOA, surface and atmosphere are ?5.2, ?12.2 and +6.8 W m?2 for the Po Valley case, and ?6.5, ?13.0 and +6.5 W m?2 for the AAOT site but these values can be much higher for individual days. Concurrent clear-sky days give indications on the regional atmospheric heating spatial gradients. Differences between the atmospheric ADRE at the two locations average 6.3 W m?2 with a gradient positive towards the inner valley in 65% of the cases. This study confirms the importance of duly considering the radiative impact of aerosols on the regional climate
Experimental characterization of lithium-ion cell strain using laser sensors
The characterization of thickness change during operation of LFP/Graphite prismatic batteries is presented in this work. In this regard, current rate dependence, hysteresis behaviour between charge and discharge and correlation with phase changes are deepened. Experimental tests are carried out with a battery testing equipment correlated with optical laser sensors to evaluate swelling. Furthermore, thickness change is computed analytically with a mathematical model based on lattice parameters of the crystal structures of active materials. The results of the model are validated with experimental data. Thickness change is able to capture variations of the internal structure of the battery, referred to as phase change, characteristic of a certain state of charge. Furthermore, phase change shift is a characteristic of battery ageing. Being able to capture these properties with sensors mounted on the external surface the cell is a key feature for improving state of charge and state of health estimation in battery management system
Phase-Insensitive Scattering of Terahertz Radiation
The nonlinear interaction between Near-Infrared (NIR) and Terahertz pulses is
principally investigated as a means for the detection of radiation in the
hardly accessible THz spectral region. Most studies have targeted second-order
nonlinear processes, given their higher efficiencies, and only a limited number
have addressed third-order nonlinear interactions, mainly investigating
four-wave mixing in air for broadband THz detection. We have studied the
nonlinear interaction between THz and NIR pulses in solid-state media
(specifically diamond), and we show how the former can be frequency-shifted up
to UV frequencies by the scattering from the nonlinear polarisation induced by
the latter. Such UV emission differs from the well-known electric-field-induced
second harmonic (EFISH) one, as it is generated via a phase-insensitive
scattering, rather than a sum- or difference-frequency four-wave-mixing
process
Synthesis, Conformation and Antiproliferative Activity of Isothiazoloisoxazole 1,1-dioxides
Sixteen new isothiazoloisoxazole 1,1-dioxides, one new isothiazolotriazole and one new isothiazolopyrazole have been synthesised by using 1,3-dipolar cycloadditions to isothiazole 1,1-dioxides. One sub-set of these isothiazoloisoxazoles showed low μM activity against a human breast carcinoma cell line, whilst a second sub-set plus the isothiazolotriazole demonstrated an interesting restricted rotation of sterically hindered bridgehead substituents. A thiazete 1,1-dioxide produced from one of the isothiazole 1,1-dioxides underwent conversion into an unknown 1,2,3-oxathiazolin-2-oxide upon treatment with Lewis acids, but was inert towards 1,3-dipoles and cyclopropenones. Six supporting crystal structures are included
Reply to Comment on: Hawking radiation from ultrashort laser pulse filaments
A comment by R. Schutzhold et al. raises possible concerns and questions
regarding recent measurements of analogue Hawking radiation. We briefly reply
to the opinions expressed in the comment and sustain that the origin of the
radiation may be understood in terms of Hawking emission
Robot therapy for functional recovery of the upper limbs: a pilot study on patients after stroke.
Objective: To verify the possibility of administering robotaided therapy for the upper limbs in patients after stroke; to evaluate patients' degree of acceptance and compliance with the treatment; to establish if the treatment has an effect on motor impairment and functional outcome. Design: Quasi-experimental, uncontrolled study. Subjects: Fourteen patients with chronic hemiparesis after stroke. Methods: Patients were treated with a robotic system for the upper limbs (ReoGo TM ; Motorika Medical Ltd, Israel). Subjects performed the following assessment, at the start (T0), at the end of treatment (T1), and at the follow-up performed one month after the end of treatment (T2): Fugl-Meyer test (FM) for upper limbs; strength evaluation; Ashworth scale; visual analogue scale (VAS) for pain; Frenchay Arm test (FAT); Box and Block test (BB Functional Independence Measure (FIM TM ); ABILHAND Questionnaire; Timed Up and Go test (TUG); Euro-Quality of Life questionnaire and; a VAS for treatment satisfaction were administered to the subjects. Results: Total scores of FM, B&B, FAT and FIM TM showed a statistically significant improvement from T0 and T1 (FM p < 0.002, B&B p < 0.012, FAT p < 0.023, FIM TM p < 0.007) and from T0 and T2 (FM p < 0.003, B&B p < 0.011, FAT p < 0.024, FIM p < 0.027). No statistically significant differences were found between evaluations at T1 and T2 (FM p < 0.595, B&B p < 0.491, FAT p < 0.317, FIM p < 0.180). Conclusion: The sample was capable of completing the treatment and demonstrated good participant satisfaction. This pilot study led to the finding of a clinical improvement and excellent patient compliance. It can be hypothesized that the results are robot-dependent and that they were learned and then maintained. However, the study is limited in that a control group was not used. As such, it is desirable to continue this study with a control group, as well as by designing a prospective longitudinal randomized controlled trial study
Spatiotemporal Amplitude and Phase Retrieval of Bessel-X pulses using a Hartmann-Shack Sensor
We propose a new experimental technique, which allows for a complete
characterization of ultrashort optical pulses both in space and in time.
Combining the well-known Frequency-Resolved-Optical-Gating technique for the
retrieval of the temporal profile of the pulse with a measurement of the
near-field made with an Hartmann-Shack sensor, we are able to retrieve the
spatiotemporal amplitude and phase profile of a Bessel-X pulse. By following
the pulse evolution along the propagation direction we highlight the
superluminal propagation of the pulse peak
IL-33 and its decoy sST2 in patients with Alzheimer's disease and mild cognitive impairment
BACKGROUND: Interleukin-33 is a cytokine endowed with pro- and anti-inflammatory properties that plays a still poorly defined role in the pathogenesis of a number of central nervous system (CNS) conditions including Alzheimer's disease (AD). We analyzed this cytokine and its decoy receptor sST2 in Alzheimer's disease (AD) and mild cognitive impairment (MCI). METHOD: IL-33 and sST2 were analyzed in serum and CSF of AD and MCI patients, comparing the results to those obtained in age-matched healthy controls (HC). Because of the ambiguous role of IL-33 in inflammation, the concentration of both inflammatory (IL-1\u3b2 and IL-6) and anti-inflammatory (IL-10) cytokines was analyzed as well in serum and cerebrospinal fluid (CSF) of the same individuals. Finally, the effect of IL-33 on in vitro A\u3b242-stimulated monocytes of AD, MCI, and HC individuals was examined. RESULTS: As compared to HC, (1) IL-33 was significantly decreased in serum and CSF of AD and MCI, (2) sST2 was increased in serum of AD and MCI but was undetectable in CSF, (3) serum and CSF IL-1\u3b2 concentration was significantly increased and that of IL-10 was reduced in AD and MCI, whereas no differences were observed in IL-6. In vitro addition of IL-33 to LPS+A\u3b2 42-stimulated monocytes downregulated IL-1\u3b2 generation in MCI and HC, but not in AD, and stimulated IL-10 production in HC alone. IL-33 addition also resulted in a significant reduction of NF-kB nuclear translocation in LPS+A\u3b242-stimulated monocytes of HC alone. CONCLUSIONS: These data support the hypothesis that IL-33 plays a complex anti-inflammatory role that is lost in AD- and MCI-associated neuroinflammation; results herein also suggest a possible use of IL-33 as a novel therapeutic approach in AD and MCI
The Origin of Massive Compact Galaxies: Lessons from IllustrisTNG
We investigate the formation and evolution of z=0 massive compact galaxies
(MCGs) in the IllustrisTNG cosmological simulation. We found that, as in
observations, MCGs are mainly old (median age Gyr), have
super-solar metallicities (median ) and are
-enhanced (median ). The age distribution extends
to younger ages, however, and a few MCGs are as young as Gyr. In
general, MCGs assemble their mass early and accrete low angular momentum gas,
significantly increasing their mass while growing their size much slower. A
small fraction of MCGs follow another evolutionary path, going through a
compaction event, with their sizes shrinking by 40% or more. The accretion of
low angular momentum gas leads to enhanced SMBH growth, and MCGs reach the
threshold SMBH mass of - when kinetic
AGN feedback kicks in and quenches the galaxy - earlier than non-compact
galaxies. Comparing MCGs to a sample of median-sized quiescent galaxies matched
in effective velocity dispersion, we find that their accretion histories are
very different. 71% of MCGs do not merge after quenching compared to 37% of
median-sized quiescent galaxies. Moreover, tracing these populations back in
time, we find that at least a third of median-sized quiescent galaxies do not
have a compact progenitor, underscoring that both dry mergers and progenitor
bias effects are responsible for the differences in the kinematics and stellar
population properties of MCGs and median-sized quiescent galaxies.Comment: 15 pages, 15 figures (not including appendices). Accepted for
publication in the Monthly Notices of the Royal Astronomical Societ
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