A dispersive wave pattern on Jupiter's fastest retrograde jet at 20∘20^\circS

A compact wave pattern has been identified on Jupiter's fastest retrograding jet at 20S (the SEBs) on the southern edge of the South Equatorial Belt. The wave has been identified in both reflected sunlight from amateur observations between 2010 and 2015, thermal infrared imaging from the Very Large Telescope and near infrared imaging from the Infrared Telescope Facility. The wave pattern is present when the SEB is relatively quiescent and lacking large-scale disturbances, and is particularly notable when the belt has undergone a fade (whitening). It is generally not present when the SEB exhibits its usual large-scale convective activity ('rifts'). Tracking of the wave pattern and associated white ovals on its southern edge over several epochs have permitted a measure of the dispersion relationship, showing a strong correlation between the phase speed (-43.2 to -21.2 m/s) and the longitudinal wavelength, which varied from 4.4-10.0 deg. longitude over the course of the observations. Infrared imaging sensing low pressures in the upper troposphere suggest that the wave is confined to near the cloud tops. The wave is moving westward at a phase speed slower (i.e., less negative) than the peak retrograde wind speed (-62 m/s), and is therefore moving east with respect to the SEBs jet peak. Unlike the retrograde NEBn jet near 17N, which is a location of strong vertical wind shear that sometimes hosts Rossby wave activity, the SEBs jet remains retrograde throughout the upper troposphere, suggesting the SEBs pattern cannot be interpreted as a classical Rossby wave. Cassini-derived windspeeds and temperatures reveal that the vorticity gradient is dominated by the baroclinic term and becomes negative (changes sign) in a region near the cloud-top level (400-700 mbar) associated with the SEBs, suggesting a baroclinic origin for this meandering wave pattern. [Abr]Comment: 19 pages, 11 figures, article accepted for publication in Icaru

Prospects for intermediate mass black hole binary searches with advanced gravitational-wave detectors

We estimated the sensitivity of the upcoming advanced, ground-based gravitational-wave observatories (the upgraded LIGO and Virgo and the KAGRA interferometers) to coalescing intermediate mass black hole binaries (IMBHB). We added waveforms modeling the gravitational radiation emitted by IMBHBs to detectors' simulated data and searched for the injected signals with the coherent WaveBurst algorithm. The tested binary's parameter space covers non-spinning IMBHBs with source-frame total masses between 50 and 1050 $\text{M}_{\odot}$ and mass ratios between $1/6$ and 1$\,$. We found that advanced detectors could be sensitive to these systems up to a range of a few Gpc. A theoretical model was adopted to estimate the expected observation rates, yielding up to a few tens of events per year. Thus, our results indicate that advanced detectors will have a reasonable chance to collect the first direct evidence for intermediate mass black holes and open a new, intriguing channel for probing the Universe over cosmological scales.Comment: 9 pages, 4 figures, corrected the name of one author (previously misspelled

Enhancing the significance of gravitational wave bursts through signal classification

The quest to observe gravitational waves challenges our ability to discriminate signals from detector noise. This issue is especially relevant for transient gravitational waves searches with a robust eyes wide open approach, the so called all- sky burst searches. Here we show how signal classification methods inspired by broad astrophysical characteristics can be implemented in all-sky burst searches preserving their generality. In our case study, we apply a multivariate analyses based on artificial neural networks to classify waves emitted in compact binary coalescences. We enhance by orders of magnitude the significance of signals belonging to this broad astrophysical class against the noise background. Alternatively, at a given level of mis-classification of noise events, we can detect about 1/4 more of the total signal population. We also show that a more general strategy of signal classification can actually be performed, by testing the ability of artificial neural networks in discriminating different signal classes. The possible impact on future observations by the LIGO-Virgo network of detectors is discussed by analysing recoloured noise from previous LIGO-Virgo data with coherent WaveBurst, one of the flagship pipelines dedicated to all-sky searches for transient gravitational waves

Air quality during uncontrolled fires: a multi-years case of study

Exposure to high level of pollutant as a consequence of uncontrolled fire is a issue that must be managed in the right way in order to protect environment and ensure a safe habitat for humans, flora and fauna, because is well know that emissions occurred during those events could serious contaminate air soil and water, and some pollutant could be hazardous for the human health (Lemieux, 2002). During uncontrolled fires a lot of contaminants may be emitted, but in high concern for the human health are persistent organic pollutants (POPs) and PAHs (Coudon et al., 2019, Zhang et al., 2008). Moreover uncontrolled burning could release polychlorinated biphenyls dioxin-like (PCB dl), that are generated as by-product during industrial combustions. Those pollutants are all of high concern for human health because they have well-known carcinogenic and mutagenic properties, e.g. is well known that PAHs is the main carcinogenic constituent of ambient aerosol (Zhang et al., 2008, Fent et al., 2018; Ravindra et al., 2008). Moreover, PCDD/PCDF, frequently referred as dioxin, are recognized as toxic chemical pollutant, with endocrine proprieties and toxic dioxin congener is classified as group1 carcinogen by the international agency for research in cancer (IARC). The aim of this study is evaluate how uncontrolled fires can affect air quality by characterizing persistent organic pollutant emitted from some events occurred from 2015 to 2018 in Veneto region (northern Italy). This area is one of the most polluted and urbanized areas in Europe (Larsen et al., 2012)and uncontrolled fire can further enhance this severe situation, leading air pollution to critical level. During those accidental events the Environmental Protection Agency of Veneto (ARPAV), in order to monitoring the effect of fires, and ensure public health, collected some air samples using Hi-vol samplers equipped with quartz fiber filter (QFF) for collecting “particulate” phase compounds and a polyurethane foam plug (PUF) for retaining “gas-phase” compounds. Subsequently, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), polychlorinated biphenyls dioxin-like (PCB dl) and Polycyclic aromatic hydrocarbons (PAHs), were analysed using a High Resolution Gas Chromatography (HRGC), coupled with High Resolution Mass Spectrometry (HRMS). As expected results show large increase of PCDD/PCDF, PCB dl and PAHs during and immediately after incidental fires, with differences in pollutant composition. It’s noticeable how, in a few time (hours to days) pollutant concentration presented a clear and strong drop, leading air quality to better conditions. This drop is probably due to meteorological factors, that will be investigated

Bacterial community analysis on the Mediaeval stained glass window "Natività" in the Florence Cathedral

Microbial corrosion of glass causes problems on delicates antique glass samples. Until now, the effect of microbial activity on corrosion phenomena has not been well documented. Only a few studies have been published concerning the microflora growing on glass surfaces. The present study deals with the characterization of cultivable aerobic bacteria isolated from the historical glass window "Natività" in the Florence Cathedral, designed by Paolo Uccello and realized by Angelo Lippi between 1443 and 1444. Microbial strains were sampled from four of the 25 panels of the "Natività" in the occasion of a recent conservation treatment, due to the presence of various kinds of crusts. One hundred microorganisms were isolated, about 50% bacteria and 50% fungi. Bacteria were submitted to morphological characterization and classified in the Gram group. For twenty strains, from different glass panels, the 16S rDNA gene was amplified and sequenced. Sequence analysis showed genus Bacillus, Arthrobacter and Paenibacillus as the most representative. In particular Bacillus and Paenibacillus are crusts associated. Phylogenetic relationship among isolates was determined. Chemical analysis of the glass and crusts completed the study

Feedback cooling of the normal modes of a massive electromechanical system to submillikelvin temperature

We apply a feedback cooling technique to simultaneously cool the three electromechanical normal modes of the ton-scale resonant-bar gravitational wave detector AURIGA. The measuring system is based on a dc Superconducting Quantum Interference Device (SQUID) amplifier, and the feedback cooling is applied electronically to the input circuit of the SQUID. Starting from a bath temperature of 4.2 K, we achieve a minimum temperature of 0.17 mK for the coolest normal mode. The same technique, implemented in a dedicated experiment at subkelvin bath temperature and with a quantum limited SQUID, could allow to approach the quantum ground state of a kilogram-scale mechanical resonator.Comment: 4 pages, 4 figure

Timing with resonant gravitational wave detectors: An experimental test

We measure the time of arrival ${t}_{0}$ of a force signal acting on a room temperature gravitational wave antenna. The antenna has a noise spectral density whose shape is a rescaled replica of that predicted for the two subkelvin antennas located in Italy, once at their sensitivity goal. ${t}_{0}$ is expressed as {t}_{0}{=t}_{\ensuremath{\varphi}}{+kT}_{0} where ${T}_{0}$ is half the natural period of oscillation of the antenna, |{t}_{\ensuremath{\varphi}}|l~{T}_{0}/2, and $k$ is an integer. We measure the phase part {t}_{\ensuremath{\varphi}} with an accuracy of {\ensuremath{\sigma}}_{{t}_{\ensuremath{\varphi}}}\ensuremath{\approx}174\mathrm{\ensuremath{\mu}}\mathrm{s}/\mathrm{S}\mathrm{N}\mathrm{R}, where SNR is the signal to noise ratio for the signal amplitude. We also find that, for $\mathrm{SNR}g~20,$ the error on $k$ is \ensuremath{\delta}k\ensuremath{\ll}1 so that the total statistical error on the arrival time reduces to the phase error {\ensuremath{\sigma}}_{{t}_{\ensuremath{\varphi}}}. We discuss how this last result can be achieved even for smaller values of the SNR, by better tuning the modes of the antenna. We finally discuss the relevance of these results for source location and spuria events rejection with the two subkelvin detectors above

Comparação entre os índices espectrais EVI e EVI 2 para discriminação de pastagens plantadas e naturais.

A identificação e discriminação de espécies vegetais semelhantes, tais como pastagens plantadas (PP) e pastagens naturais (PN), constitui um desafio em decorrência da semelhança espectral entre essas classes. Assumindo-se uma premissa de que bandas espectrais na faixa do visível têm elevada correlação, os índices de vegetação (IVs) vêm contribuindo para a discriminação de classes. Portanto, este trabalho tem como objetivo analisar o comportamento do índice EVI 2 (índice de vegetação realçado, do inglês Enhanced Vegetation Index) na discriminação de alvos de PN e PP para dois períodos sazonais, comparando-o ao EVI. Para o desenvolvimento do trabalho, foram utilizadas 14 imagens do satélite TM/Landsat 5 em uma série temporal de sete anos, entre 2004 e 2010. De acordo com os resultados obtidos, pode-se concluir que, em geral, o EVI 2 mantém a correlação com dados do EVI, caracterizando sutilmente melhor a influência da sazonalidade nos dados

A burst search for gravitational waves from binary black holes

Compact binary coalescence (CBC) is one of the most promising sources of gravitational waves. These sources are usually searched for with matched filters which require accurate calculation of the GW waveforms and generation of large template banks. We present a complementary search technique based on algorithms used in un-modeled searches. Initially designed for detection of un-modeled bursts, which can span a very large set of waveform morphologies, the search algorithm presented here is constrained for targeted detection of the smaller subset of CBC signals. The constraint is based on the assumption of elliptical polarisation for signals received at the detector. We expect that the algorithm is sensitive to CBC signals in a wide range of masses, mass ratios, and spin parameters. In preparation for the analysis of data from the fifth LIGO-Virgo science run (S5), we performed preliminary studies of the algorithm on test data. We present the sensitivity of the search to different types of simulated CBC waveforms. Also, we discuss how to extend the results of the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in the special issue for the conference proceedings of GWDAW13; corrected some typos, addressed some minor reviewer comments one section restructured and references updated and correcte