A gas-rich AGN near the centre of a galaxy cluster at z ~ 1.4

The formation of the first virialized structures in overdensities dates back to ~9 Gyr ago, i.e. in the redshift range z ~ 1.4 - 1.6. Some models of structure formation predict that the star formation activity in clusters was high at that epoch, implying large reservoirs of cold molecular gas. Aiming at finding a trace of this expected high molecular gas content in primeval clusters, we searched for the 12CO(2-1) line emission in the most luminous active galactic nucleus (AGN) of the cluster around the radio galaxy 7C 1756+6520 at z ~ 1.4, one of the farthest spectroscopic confirmed clusters. This AGN, called AGN.1317, is located in the neighbourhood of the central radio galaxy at a projected distance of ~780 kpc. The IRAM Plateau de Bure Interferometer was used to investigate the molecular gas quantity in AGN.1317, observing the 12CO(2-1) emission line. We detect CO emission in an AGN belonging to a galaxy cluster at z ~ 1.4. We measured a molecular gas mass of 1.1 x 10^10 Msun, comparable to that found in submillimeter galaxies. In optical images, AGN.1317 does not seem to be part of a galaxy interaction or merger.We also derived the nearly instantaneous star formation rate (SFR) from Halpha flux obtaining a SFR ~65 Msun/yr. This suggests that AGN.1317 is actively forming stars and will exhaust its reservoir of cold gas in ~0.2-1.0 Gyr.Comment: 5 pages, 3 figures, accepted for publication in Astronomy & Astrophysic

Municipal solid waste prevention: A review of market-based instruments in six European Union countries

This article focuses on quantitative prevention of municipal solid waste among the 28 member countries of the European Union. A strict definition of waste prevention is used, including waste avoidance, waste reduction at source or in process, and product reuse, while recycling is outside the scope of this article. In order to provide a solid overview of the European situation, the study selected six countries (Belgium, Bulgaria, Italy, the Netherlands, Romania and Spain). Several selection requirements have been considered, such as geographic location or municipal solid waste per capita production trends from 1995 to 2017. A review of prevention programmes and other national strategic documents has been conducted. Extended producer responsibility, Pay-As-You-Throw schemes, Deposit-Refund Systems and Environmental Taxes implementation among the selected countries have been studied in order to understand how these market-based instruments can be used for the sake of waste prevention. Each market-based instrument has been further analysed using the Drivers Pressures State Impact Response model. Based on the results of this study, the effectiveness of market-based instruments implementation is strictly related to the context they are enforced in. It is particularly important to tailor the market-based instruments based on the implementation area. Nevertheless, market-based instruments, which are now mostly meant to boost the recycling sector of the considered Member States, should be designed to improve waste prevention performances, ensuring the achievement of the highest level of waste hierarchy promoted by the European Union

Human-robot coexistence and interaction in open industrial cells

Recent research results on human\u2013robot interaction and collaborative robotics are leaving behind the traditional paradigm of robots living in a separated space inside safety cages, allowing humans and robot to work together for completing an increasing number of complex industrial tasks. In this context, safety of the human operator is a main concern. In this paper, we present a framework for ensuring human safety in a robotic cell that allows human\u2013robot coexistence and dependable interaction. The framework is based on a layered control architecture that exploits an effective algorithm for online monitoring of relative human\u2013robot distance using depth sensors. This method allows to modify in real time the robot behavior depending on the user position, without limiting the operative robot workspace in a too conservative way. In order to guarantee redundancy and diversity at the safety level, additional certified laser scanners monitor human\u2013robot proximity in the cell and safe communication protocols and logical units are used for the smooth integration with an industrial software for safe low-level robot control. The implemented concept includes a smart human-machine interface to support in-process collaborative activities and for a contactless interaction with gesture recognition of operator commands. Coexistence and interaction are illustrated and tested in an industrial cell, in which a robot moves a tool that measures the quality of a polished metallic part while the operator performs a close evaluation of the same workpiece

Earthquake Characteristics and Structural Properties of the Southern Tyrrhenian Basin from Full Seismic Wave Simulations

Modelling the response of seismic wavefields to sharp lateral variations in crustal discontinuities is essential for seismic tomography application and path effects correction in earthquake source characterization. This is particularly relevant when wavefields cross back-arc oceanic basins, i.e. mixed continental-oceanic settings. High-frequency (> 0.05 Hz) seismic waves resonate and get absorbed across these settings due to a shallow Moho, crustal heterogeneities, and energy leakage. Here, we provide the first high-frequency wave-equation model of full seismograms propagating through realistic 3D back-arc basins. Inversion by parameters trial based on correlation analyses identifies P-, S-and coda-wave as attributes able to estimate jointly 3D Moho variations, sediment thickness, and earthquake source characteristics using data from a single regional earthquake. We use as data waveforms produced by the Accumoli earthquake (Central Italy, 2016), propagating across the Southern Tyrrhenian basin and recorded across Southern Italy. The best model comprises a deep Moho ( similar to 18 km) in the middle of the basin and a crustal pinch with the continental crust in Sicily. The deep Moho corresponds to the Issel Bridge, a portion of continental crust trapped between the Vavilov and Marsili volcanic centres. The Accumoli earthquake is optimally described at a depth of 7.3 km using a boxcar with rise time of 6 s. Our results show that the early S-wave coda comprises trapped and reverberating phases sensitive to crustal interfaces. Forward modelling these waves is computationally expensive; however, adding these attributes to tomographic procedures allows modelling both source and structural parameters across oceanic basins

HII regions within a compact high velocity cloud. A nearly star-less dwarf galaxy?

Within the SECCO survey we identified a candidate stellar counterpart to the Ultra Compact High Velocity Cloud (UCHVC) HVC274.68+74.70-123, that was suggested by Adams et al. (2013) as a possible mini-halo within the Local Group of galaxies. The spectroscopic follow-up of the brightest sources within the candidate reveals the presence of two HII regions whose radial velocity is compatible with physical association with the UVHVC. The available data does not allow us to give a definite answer on the nature of the newly identified system. A few alternative hypotheses are discussed. However, the most likely possibility is that we have found a new faint dwarf galaxy residing in the Virgo cluster of galaxies, which we name SECCO-1. Independently of its actual distance, SECCO-1 displays a ratio of neutral hydrogen mass to V luminosity of M_{HI}/L_V>= 20, by far the largest among local dwarfs. Hence, it appears as a nearly star-less galaxy and it may be an example of the missing links between normal dwarfs and the dark mini halos that are predicted to exist in large numbers according to the currently accepted cosmological model.Comment: Accepted for publication in ApJ Letters. Pdflatex, emulateapj.cls. 6 pages, 3 figures, 2 table

Cool gas and dust in M33: Results from the Herschel M33 extended survey (HERM33ES)

We present an analysis of the first space-based far-IR-submm observations of M 33, which measure the emission from the cool dust and resolve the giant molecular cloud complexes. With roughly half-solar abundances, M33 is a first step towards young low-metallicity galaxies where the submm may be able to provide an alternative to CO mapping to measure their H$_2$ content. In this Letter, we measure the dust emission cross-section $\sigma$ using SPIRE and recent CO and \HI\ observations; a variation in $\sigma$ is present from a near-solar neighborhood cross-section to about half-solar with the maximum being south of the nucleus. Calculating the total H column density from the measured dust temperature and cross-section, and then subtracting the \HI\ column, yields a morphology similar to that observed in CO. The H$_2$/\HI\ mass ratio decreases from about unity to well below 10% and is about 15% averaged over the optical disk. The single most important observation to reduce the potentially large systematic errors is to complete the CO mapping of M 33.Comment: 5 pages, 5 figures Accepted for publication in Astronomy and Astrophysic

Gas accretion as the origin of chemical abundance gradients in distant galaxies

It has recently been suggested that galaxies in the early Universe can grow through the accretion of cold gas, and that this may have been the main driver of star formation and stellar mass growth. Because the cold gas is essentially primordial, it has a very low abundance of elements heavier than helium (metallicity). As it is funneled to the centre of a galaxy, it will lead the central gas having an overall lower metallicity than gas further from the centre, because the gas further out has been enriched by supernovae and stellar winds, and not diluted by the primordial gas. Here we report chemical abundances across three rotationally-supported star-forming galaxies at z~3, only 2 Gyr after the Big Bang. We find an 'inverse' gradient, with the central, star forming regions having a lower metallicity than less active ones, opposite to what is seen in local galaxies. We conclude that the central gas has been diluted by the accretion of primordial gas, as predicted by 'cold flow' models.Comment: To Appear in Nature Oct 14, 2010; Supplementary Information included her

Planetary nebulae in M33: probes of AGB nucleosynthesis and ISM abundances

We have obtained deep optical spectrophotometry of 16 planetary nebulae in M33, mostly located in the central two kpc of the galaxy, with the Subaru and Keck telescopes. We have derived electron temperatures and chemical abundances from the detection of the [OIII]4363 line for the whole sample. We have found one object with an extreme nitrogen abundance, 12+log(N/H)=9.20, accompanied by a large helium content. After combining our data with those available in the literature for PNe and HII regions, we have examined the behavior of nitrogen, neon, oxygen and argon in relation to each other, and as a function of galactocentric distance. We confirm the good correlation between Ne/H and O/H for PNe in M33. Ar/H is also found to correlate with O/H. This strengthens the idea that at the metallicity of the bright PNe analyzed in M33, which is similar to that found in the LMC, these elements have not been significantly modified during the dredge-up processes that take place during the AGB phase of their progenitor stars. We find no significant oxygen abundance offset between PNe and HII regions at any given galactocentric distance, despite the fact that these objects represent different age groups in the evolution of the galaxy. Combining the results from PNe and HII regions, we obtain a representative slope of the ISM alpha-element (O, Ar, Ne) abundance gradient in M33 of -0.025 +/- 0.006 dex/kpc. Both PNe and HII regions display a large abundance dispersion at any given distance from the galactic center. We find that the N/O ratio in PNe is enhanced, relative to the HII regions, by approximately 0.8 dex.Comment: 21 pages, 20 figures. Accepted for publication in MNRA

Correlation between birth weight and placental weight in healthy and diabetic puerperae

Abstract Objective The birth weight/placental weight ratio has an important predictive value for perinatal mortality and morbidity and for cardiovascular diseases in adult life. In this study, we compared the birth weight/placental weight (BW/PW) ratio and the correlation between the two parameters in diabetic women with that observed in healthy women. Materials and Methods A total of 347 consecutive newborn infants from healthy puerperae, 164 newborns from puerperae with gestational diabetes, 148 newborns from puerperae with preexisting type 1 diabetes, and 40 newborns from puerperae with preexisting type 2 diabetes have been studied from the White population of Rome. The research project was approved by the Institutional Review Board and informed written consent was obtained from the participating mothers. Results The BW/PW ratio is higher, and the correlation between the two parameters is lower in all classes of diabetes as compared to healthy puerperae. A remarkably low correlation is observed in preexisting diabetes pointing to a dissociation of fetal growth from placental growth. Discussion In diabetic pregnancy the BW/PW ratio is higher, and the correlation between birth weight and placental weight is lower in all classes of diabetic as compared to healthy puerperae pointing to a relative dissociation between the two parameters. It has been suggested that the increase of glycemic levels in diabetic pregnancy predisposes to important diseases in adult life. The dissociation of BW from PW in infants of diabetic pregnancy could be a predictor of the risk for such diseases of adult life