Primary gas thermometry by means of laser-absorption spectroscopy: Determination of the Boltzmann constant

We report on a new optical implementation of primary gas thermometry based on laser absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) $\nu_{1} + 2 \nu_{2}^{\phantom{1}0} + \nu_{3}$ transition in CO$_{2}$ gas at thermodynamic equilibrium. Doppler width measurements as a function of gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of $\sim1.6\times10^{-4}$.Comment: Submitted to Physical Review Letter

Engineering geological map of the Chiavari city area (Liguria, Italy)

An engineering geological map at a scale of 1:10,000 of the Chiavari city area (Northern Italy) – a major tourist and economic attraction of the Ligurian East Riviera – is presented in this paper. The municipality land shows an excellent geomorphological case-study of the well-known Ligurian coast: a floodplain, fairly wide and inhabited, formed by several floods of the two main rivers, a hill hinterland, reasonably inhabited, developed in marly limestones and sandy shales flysch and the coast – featuring cliffs and narrow pebbly beaches – deeply modified. This map was compiled by combining available geological data with a new engineering geomorphological field survey and including geotechnical data which were obtained from studies carried out for town planning and building purposes. On the basis of the critical review of the available lithostratigraphic data from drilling, as well as geotechnical and geophysical analyses carried out between 1981 and 2010 on the municipality land, an engineering geologica..

Via-Less Microstrip to Rectangular Waveguide Transition on InP

Indium-Phosphide (InP) is one of the most common materials used for realizing active devices working in the millimeter frequency range. The isotropic etching profile of InP substrates limits the realization of passive devices, thus requiring an expensive and lossy hybrid platform. This paper presents a via-less, cost-effective and efficient solution for InP substrate. By using the proposed planar solution, it is demonstrated that rectangular waveguides can be realized on InP by fabricating a bed of nails structure which acts as a reflecting boundary for an impinging millimeter wave. As a proof of concept, a transition from microstrip to rectangular waveguide structure is realized within H-band (220-320 GHz) with a return loss of -18dB over a bandwidth of 30 GHz

Extensión del primer catálogo Astrolabio de San Juan : Programa de catálogo

Se ha formado un programa suplementario denominado de Catálogo que será observado paralelamente al programa fundamental de tiempo y latitud, el cual se tomará como referencia en el procesamiento final para la determinación de ΔxyΔδ de aprox. 300 estrellas.Asociación Argentina de Astronomí

Flexible multi-band OFDM receiver based on optical down-conversion for millimeter waveband wireless base stations

A novel and flexible photonics-based down-conversion scheme is proposed for wireless receivers in base stations. It allows simultaneous detection of multiple signals at carriers up to tens of GHz, enabling communications at millimeter waves. Experiments demonstrate the effective down-conversion of Wi-Fi signals at 2.4 and 39.8GHz with EVM<;-43dB

Photonics enabling coherent MIMO radar networks

The potential of coherent MIMO radar networks enabled by photonics is introduced. The first coherent dual-band 2 × 4 MIMO radar experiment is presented. Range/cross-range maps demonstrate the higher cross-range resolution due to the coherence and the enhanced performance introduced by dual-band operation

Why polls fail to predict elections

In the past decade we have witnessed the failure of traditional polls in predicting presidential election outcomes across the world. To understand the reasons behind these failures we analyze the raw data of a trusted pollster which failed to predict, along with the rest of the pollsters, the surprising 2019 presidential election in Argentina which has led to a major market collapse in that country. Analysis of the raw and re-weighted data from longitudinal surveys performed before and after the elections reveals clear biases (beyond well-known low-response rates) related to mis-representation of the population and, most importantly, to social-desirability biases, i.e., the tendency of respondents to hide their intention to vote for controversial candidates. We then propose a longitudinal opinion tracking method based on big-data analytics from social media, machine learning, and network theory that overcomes the limits of traditional polls. The model achieves accurate results in the 2019 Argentina elections predicting the overwhelming victory of the candidate Alberto Fern\'andez over the president Mauricio Macri; a result that none of the traditional pollsters in the country was able to predict. Beyond predicting political elections, the framework we propose is more general and can be used to discover trends in society; for instance, what people think about economics, education or climate change.Comment: 47 pages, 10 tables, 15 figure

Quantum Radar: State of the Art and Potential of a Newly-Born Remote Sensing Technology

Quantum technology has already been introduced in many fields, like information processing and communications, and it can potentially change our approach to remote sensing in the microwave and millimeter-wave domain, leading to systems known as Quantum Radars. This new generation of systems does not leverage directly on quantum entanglement, since the latter is too “fragile” to preserve in a noisy and lossy environment,as a radar scenario,but rather on thehigh level of coherence derived from quantum entanglement. Quantum Illuminationisaprocess that exploitsquantum coherence of non-classical states of lightfor remote sensing. It allows for the generation and reception of highly correlatedsignals in the form of optical ormicrowave photons. By correlating the received signal photons with photons entangled with the transmitted ones,it is possible toclearly distinguish, among all the received photons, the echoes from background noise and interferences, boosting to an unprecedented level the sensitivity of remote sensing. Therefore, in principle,it is possible to detect very lowcross-radar section objets, such as stealth targets. Nowadays, very few experiments on Quantum Radar transceivers have been reported. This work aims at summarizing the state of the art of Quantum Radar, introducing its basic working principles, though raising the possible issues of such a technology; secondly, it will point out the possibilitiesof photonics-assisted Quantum Radars, proposing photonics as the ideal field where quantum science and remote sensing can meet for an effective cross-fertilizatio

Ampliación del primer catálogo Astrolabio de San Juan, programa catálogo

In order to enlarge the First Catalogue of the San Juan Astrolabe a special program, called "Catalogue Program" has been made. It will permit to compute corrections Δα and Δδ for 180 stars from the FK4 and FK4 supplement.Asociación Argentina de Astronomí

Reconfigurable radar transmitter based on photonic microwave signal generation

In this paper we propose a photonic technique for a reconfigurable microwave signal generation based on the beating in a photodiode of two laser modes from a regenerative Fiber Mode-Locked Laser (FMLL). The excellent performance of this kind of pulsed laser guarantees high stability to the generated microwave signal even at ultra high frequencies (up to W band). Therefore, by using the proposed architecture, the performance of a reconfigurable full digital coherent radar system can be enhanced in terms of Moving Target Indicator (MTI) improvement factor. Moreover, thanks to the achievable high repetition rates and the coherence properties of the FMLL, this laser scheme has also been proposed for digitizing the received signal by electro-optical sampling. Thus the advantage of using just one device for signal generation in both the transmitter and receiver chain, makes the proposed solution a cost effective architecture for microwave signal generation. Differently from the microwave synthesizers, whose performance strongly deteriorate with increasing frequencies, the photonic radio frequency generation always shows an excellent spectral purity. The results show excellent spectral purity above 5 KHz for the proposed technique compared to a state of the art Agilent synthesizer even though the timing jitter increases for integration time greater than 10 msec. In order to achieve the same stability performance at both high and low frequencies a Phase Locked Loop between the laser and a synthesizer could be used