2,957 research outputs found
Nanoscale electron-beam-driven metamaterial light sources
Free-standing and fiber-coupled photonic metamaterials act as nanoscale, free-electron-driven, tuneable light sources: emission occurs at wavelengths determined by structural geometry in response to electron-beam excitation of metamaterial resonant plasmonic modes
Plasmonic amplifier of the evanescent field of free electrons
We show experimentally for the first time that free electron evanescent fields can be amplified by a plasmonic nanolayer in much that same way as optical evanescent fields are amplified in the poor-man's super-lens
Comparison of MODIS and ETA profiles of atmospheric parameters in coastal zones with radiosonde data
The quality of atmospheric profiles gathered by the spaceborne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Terra platform and those predicted by the ETA atmospheric circulation model are assessed against corresponding radiosonde (RS)measurements. The analysis is carried out on a statistical basis taking as reference the radiosoundings collected at two coastal
stations, namely Ajaccio (France) and Pratica di Mare (Italy), during the spring 2000. The examined days were characterized by smooth and slow variations of the
atmospheric conditions so that a temporal lag up to about three hours between RS and MODIS profiles could be considered for comparison purposes. Both ETA predictions and MODIS retrievals compare well with RS data and their relative agreement is good. Although, as expected, the profiles of the analyzed quantities, namely temperature and moisture for both MODIS and ETA outputs and horizontal wind components predicted by ETA model, could not follow the largest fluctuations measured by RS, their averages are reproduced with a satisfactory degree of reliability. These results encourage the perspective to exploit remote measurements from the MODIS sensor of atmospheric temperature and water vapour as input to operative
circulation models, such as ETA, for reliable forecasts and detailed monitoring on global scale of the atmospheric structure and dynamics
Electron-beam-driven nanoscale metamaterials light sources
Nanoscale light (ultimately laser) and surface plasmon (ultimately 'spaser') sources for numerous potential nanophotonic applications have generated and continue to generate considerable research interest, with a variety of optically- and electrically-pumped sources recently demonstrated. We show experimentally that beams of free electrons can be used to induce light emission from nanoscale planar photonic metamaterials, at wavelengths determined by both the metamaterial design parameters and the electron energy
Amplifying free-electron evanescent fields
We show experimentally for the first time that free-electron evanescent fields can be amplified by a plasmonic nanolayer in a manner analogous to the way in which optical fields are amplified in the poor-man's superlens
Childhood vaccinations: A pilot study on knowledge, attitudes and vaccine hesitancy in pregnant women
Background. The objective of this pilot study was to test a questionnaire aimed at assessing knowledge of and attitudes towards vaccination, as well as intention to vaccinate, among pregnant women.
Methods. The questionnaire was self-administered by 49 pregnant women attending antenatal classes at three Family Centers in Rome.
Results. Poor knowledge of vaccinations, inadequate attention from healthcare professionals, recurrent consultation of unreliable sources of information, and misconceptions about the side effects of vaccines, all contribute to vaccine hesitancy. Where appropriate, questionnaire sections were shown to be internally consistent.
Conclusion. The questionnaire proved reliable and is suitable for further studies
Regional reports for the subnational monitoring of measles elimination in Italy and the identification of local barriers to the attainment of the elimination goal
Although most countries in the WHO European Region were verified in 2017 as having interrupted endemic measles transmission, nine countries were still endemic. Among these, Italy accounted for the second highest number of measles cases reported in Europe in 2017. The elimination of measles is verified at national level by each country's National Verification Committee (NVC) through the production of an Annual Status Update (ASU). Since in Italy decentralization has led to an inhomogeneous implementation of immunization strategies among the 21 administrative Regions, the Italian NVC proposed that measles elimination should also be documented at the subnational level through regional ASUs and Synthetic Regional Reports (SRRs). The regional ASUs and the SRRs for 2014, 2015 and 2016 were produced and appraised by the NVC to evaluate the Regions' performances in each individual year as well as over the whole period. A specific analysis of vaccination coverage, including official immunization data for 2017, was performed. Moreover, the measles epidemic of 2017 was examined. Firstly, in the period 2014±2016, low immunization rates were registered in most Regions. Sixty-three per cent of southern Regions reported rates below the national mean and an overall low-quality performance. The approval of Italy's mandatory vaccination law in 2017 resulted in a marked increase in vaccination coverage; however, this increase was not homogeneous among Regions. Secondly, more than 50% of Regions did not report any supplemental immunization activity (SIA) for the period 2014-2016. Thirdly, from 2014 to 2016, fewer than one-third of Regions improved their reporting of outbreaks. Finally, over the study period, only two Regions reached the target required by the WHO for measles laboratory investigations. In countries with decentralized health policies, subnational monitoring can help identify local barriers to measles elimination. In Italy it has highlighted the need for further SIAs and a stronger surveillance system
Targeting tumour-reprogrammed myeloid cells: the new battleground in cancer immunotherapy
Tumour microenvironment is a complex ecosystem in which myeloid cells are the most abundant immune elements. This cell compartment is composed by different cell types, including neutrophils, macrophages, dendritic cells, and monocytes but also unexpected cell populations with immunosuppressive and pro-tumour roles. Indeed, the release of tumour-derived factors influences physiological haematopoiesis producing unconventional cells with immunosuppressive and tolerogenic functions such as myeloid-derived suppressor cells. These pro-tumour myeloid cell populations not only support immune escape directly but also assist tumour invasion trough non-immunological activities. It is therefore not surprising that these cell subsets considerably impact in tumour progression and cancer therapy resistance, including immunotherapy, and are being investigated as potential targets for developing a new era of cancer therapy. In this review, we discuss emerging strategies able to modulate the functional activity of these tumour-supporting myeloid cells subverting their accumulation, recruitment, survival, and functions. These innovative approaches will help develop innovative, or improve existing, cancer treatments
Synergic use of SAR imagery and high resolution atmospheric model to estimate marine wind fields : an application in presence of an atmospheric gravity wave episode.
A study aimed at retrieving sea surface wind fields of semi-enclosed basins from combined use of SAR imagery and a high resolution mesoscale numerical atmospheric model, is presented. Two consecutive ERS-2 SAR frames and a set of NOAA/AVHRR and MODIS images acquired over the North Tyrrhenian Sea on March 30, 2000 were used for the analysis. SAR wind speeds and directions at 10 m above the sea surface were retrieved using the semi-empirical backscatter models CMOD4 and CMOD-IFREMER. Surface wind vectors predicted by the meteorological ETA model were exploited as guess input to SAR wind inversion procedure. ETA is a three-dimensional, primitive equation, grid-point model currently operational at the National Centers for Environmental Prediction of the U.S. National Weather Service. The model was adapted to run with a resolution up to about 4.0 Km. It was found that the inversion methodology was not able to resolve wind speed modulations due to the action of an atmospheric gravity wave, called “lee wave”, which occurred in the analyzed area. A simple atmospheric wave propagation model was thus used to account for the SAR observed surface wind speed modulation. Synergy with ETA model outputs was further exploited in simulations where atmospheric parameters up-wind the atmospheric wave were provided as input to the lee wave propagation model
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