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1. In Search of Subsurface Oceans within the Uranian Moons

Author

Cochrane, C. J., Vance, S. D., Nordheim, T. A., Styczinski, M., Masters, A., and Regoli, L. H.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Geophysics, Physics - Space Physics
Abstract

The Galileo mission to Jupiter discovered magnetic signatures associated with hidden sub-surface oceans at the moons Europa and Callisto using the phenomenon of magnetic induction. These induced magnetic fields originate from electrically conductive layers within the moons and are driven by Jupiter's strong time-varying magnetic field. The ice giants and their moons are also ideal laboratories for magnetic induction studies. Both Uranus and Neptune have a strongly tilted magnetic axis with respect to their spin axis, creating a dynamic and strongly variable magnetic field environment at the orbits of their major moons. Although Voyager 2 visited the ice giants in the 1980s, it did not pass close enough to any of the moons to detect magnetic induction signatures. However, Voyager 2 revealed that some of these moons exhibit surface features that hint at recent geologically activity, possibly associated with sub-surface oceans. Future missions to the ice giants may therefore be capable of discovering sub-surface oceans, thereby adding to the family of known ocean worlds in our solar system. Here, we assess magnetic induction as a technique for investigating sub-surface oceans within the major moons of Uranus. Furthermore, we establish the ability to distinguish induction responses created by different interior characteristics that tie into the induction response: ocean thickness, conductivity, and depth, and ionospheric conductance. The results reported here demonstrate the possibility of single-pass ocean detection and constrained characterization within the moons of Miranda, Ariel, and Umbriel, and provide guidance for magnetometer selection and trajectory design for future missions to Uranus.

Published
2021
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3. Titan's variable ionosphere during the T118-T119 Cassini flybys

Author

Edberg, N. J. T., Vigren, E., Snowden, D., Regoli, L. H., Shebanits, O., Wahlund, J. -E., Andrews, D. J., Bertucci, C., and Cui, J.

Subjects
Physics - Space Physics
Abstract

A significant difference in Titan's ionospheric electron density is observed between the T118 and T119 Cassini nightside flybys. These flybys had similar geometry, occurred at the same Saturn local time and while Titan was exposed to similar EUV and ambient magnetic field conditions. Despite these similarities, the RPWS/LP measured density differed a factor of 5 between the passes. This difference was present, and similar, both inbound and outbound. Two distinct electron peaks were present during T118, at 1150 km and 1200 km, suggesting very localised plasma production. During T118, from 1200-1350 km and below 1100 km, the lowest electron density ever observed in Titan's ionosphere are reported. We suggest that an exceptionally low rate of particle impact ionisation in combination with increased dynamics in the ionosphere could be the cause. This is, however, not verified by measurements and the measured ambient high energy particle pressure is in fact higher during T118 than during T119., Comment: 11 pages, 3 figures

Published
2018
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4. Cassini CAPS identification of pickup ion compositions at Rhea

Author

Desai, R. T., Taylor, S. A., Regoli, L. H., Coates, A. J., Nordheim, T. A., Cordiner, M. A., Teolis, B. D., Thomsen, M. F., Johnson, R. E., Jones, G. H., Cowee, M. M., and Waite, J. H.

Subjects
Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Saturn's largest icy moon, Rhea, hosts a tenuous surface-sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing CO$_2^+$ during both the R1 and R1.5 encounters. Accounting for this nongyrotropy, we show that these possess comparable alongtrack densities of $\sim$2$\times$10$^{-3}$ cm$^{-3}$. Negatively charged pickup ions, also detected during R1, are surprisingly shown as consistent with mass 26$\pm$3 u which we suggest are carbon-based compounds, such as CN$^-$, C$_2$H$^-$, C$_2^-$, or HCO$^-$, sputtered from carbonaceous material on the moons surface. These negative ions are calculated to possess alongtrack densities of $\sim$5$\times$10$^{-4}$ cm$^{-3}$ and are suggested to derive from exogenic compounds, a finding consistent with the existence of Rhea's dynamic CO$_2$ exosphere and surprisingly low O$_2$ sputtering yields. These pickup ions provide important context for understanding the exospheric and surface-ice composition of Rhea and of other icy moons which exhibit similar characteristics., Comment: 6 pages, 4 figures, submitted to Geophysical Research Letters on 29th November 2017 and accepted on 24th January 2018

Published
2017
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6. Temporal Evolution of O+ Population in the Near‐Earth Plasma Sheet During Geomagnetic Storms as Observed by the Magnetospheric Multiscale Mission.

Author

Regoli, L. H., Gkioulidou, M., Ohtani, S., Raptis, S., Mouikis, C. G., Kistler, L. M., Cohen, I. J., and Fuselier, S. A.

Subjects
AURORAS, PLASMA density, MAGNETOSPHERE, STORMS, GEOMAGNETISM, IONOSPHERE, MAGNETIC storms
Abstract

During geomagnetic storms, the increase in energy input into the ionosphere in the form of Poynting flux and electron precipitation leads to an enhanced ionospheric outflow that results in an increase of the O+ content in the magnetosphere. Using different missions and instrumentation, two main ionospheric sources have been identified for the oxygen ions reaching the inner magnetosphere during geomagnetic storms: the dayside cusp, and the night side auroral region. Evidence of both pathways have been presented in the literature. However, the relative contribution of each of these pathways to the enhancement of O+ observed in near‐Earth plasma sheet, as well as the dynamics involved during the development of geomagnetic storms remains an open question. Here, we present the first statistical study to date to address this question, in the form of a superposed epoch analysis of O+ and H+ moments obtained by the Magnetospheric Multiscale (MMS) mission throughout the main phase of 90 geomagnetic storms with a minimum SYM‐H of at least −50 nT. The results show a clear increase in the oxygen density in the near‐Earth plasma sheet, with values further from Earth remaining low. Temperature values for both species show an increase with the progress of the storms. These results combined suggest that, during the main phase of geomagnetic storms, most of the oxygen ions observed in the near‐Earth plasma sheet are traveling directly from the nightside auroral region. Key Points: Superposed epoch analysis shows dynamic evolution of O+ ions during geomagnetic stormsSignificant enhancement of the O+‐to‐H+ number density ratio observed at radial distances less than 12 REScalar temperature for both species show the arrival of heated ions far from Earth throughout the analyzed period [ABSTRACT FROM AUTHOR]

Published
2024
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7. A radiation belt of energetic protons located between Saturn and its rings

Author

Roussos, E., Kollmann, P., Krupp, N., Kotova, A., Regoli, L., Paranicas, C., Mitchell, D. G., Krimigis, S. M., Hamilton, D., Brandt, P., Carbary, J., Christon, S., Dialynas, K., Dandouras, I., Hill, M. E., Ip, W. H., Jones, G. H., Livi, S., Mauk, B. H., Palmaerts, B., Roelof, E. C., Rymer, A., Sergis, N., and Smith, H. T.

Published
2018

8. Jupiter’s radiation belts as a target for NASA’s Heliophysics Division

Author

Kollmann, P., primary, Allanson, O., additional, Arruda, L., additional, Berland, G., additional, Blum, L. W., additional, Bortnik, J., additional, Cao, X., additional, Chen, T. Y., additional, Clark, G., additional, Cohen, I., additional, Cooper, J. F., additional, Crary, F., additional, Desai, R. T., additional, Dialynas, K., additional, Drozdov, A., additional, Dudnik, O. V., additional, Dunn, W. R., additional, Hospodarsky, G. B., additional, Huybrighs, H., additional, Jackman, C. M., additional, Jaynes, A. N., additional, Jun, I., additional, Khurana, K. K., additional, Kraft, R., additional, Kronberg, E. A., additional, Lejosne, S., additional, Li, W., additional, Li, X., additional, Liuzzo, L., additional, Ma, Q., additional, Marshall, R., additional, Mauk, B., additional, Nénon, Q., additional, Nordheim, T. A., additional, Paranicas, C., additional, Plainaki, C. C., additional, Regoli, L. H., additional, Roussos, E., additional, Shprits, Y., additional, Siecard, A., additional, Simon, S., additional, Smith, H. T., additional, Sorathia, K., additional, Spence, H. E., additional, Sulaiman, A., additional, Sun, Y., additional, Tu, W., additional, Turner, D. L., additional, Usanova, M. E., additional, Williams, P., additional, Woodfield, E. E., additional, Wu, X., additional, and Yuan, C.-J., additional

Published
2023
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12. Magnetospheric Studies: A requirement for addressing interdisciplinary mysteries in the Ice Giant systems [White Paper]

Author

Kollmann, P., Allegini, F., Allen, R., André, N., Azari, A., Bagenal, F., Beddingfield, C., Brain, D., Brandt, P., Cao, X., Cartwright, R., Clark, G., Cohen, I., Cooper, J., Crary, F., Leonard, E., Paty, C., Pater, I., Desai, R., DiBraccio, G., Dietrich, W., Dong, C., Ebert, R., Felici, M., Filwett, R., Fischer, G., Gershman, D., Gkioulidou, M., Greathouse, T., Griton, L., Gritsevich, M., Hibbitts, K., Hospodarsky, G., Hue, V., Hunt, G., Huybrighs, H., Imai, M., Jackman, C., Jasinski, J., Jia, X., Jun, I., Kotova, A., Kurth, W., Lamy, L., Lazio, J., Lejosne, S., Louis, C., Masters, A., Mauk, B., Madanian, H., Mandt, K., McNutt, R., Melin, H., Miller, S., Moore, L., Nenon, Q., Neubauer, F., Nordheim, T., Palmaerts, B., Paranicas, C., Phipps, P., Regoli, L., Retherford, K., Roth, L., Roussos, E., Runyon, K., Rymer, A., Saur, J., Santos-Costa, D., SHPRITS, Y., Spilker, L., Stallard, T., Smirnov, A., Soderlund, K., Stanley, S., Sulaiman, A., Szalay, J., Turner, D., Vines, S., Wang, L., Weiss, B., Wicht, J., Wilson, R., and Woodfield, E.

Published
2021

13. Magnetospheric Studies: A requirement for addressing interdisciplinary mysteries in the Ice Giant systems

Author

Kollmann, Peter, primary, Allegini, F., additional, Allen, R. C., additional, André, N., additional, Azari, A. R., additional, Bagenal, F., additional, Beddingfield, C. B., additional, Brain, D., additional, Brandt, P., additional, Cao, X., additional, Cartwright, R. J., additional, Clark, G., additional, Cohen, I., additional, Cooper, J. F., additional, Crary, F., additional, Leonard, E. J., additional, Paty, C., additional, Pater, I. de, additional, Desai, R. T., additional, DiBraccio, G. A., additional, Dietrich, W., additional, Dong, C., additional, Ebert, R. W., additional, Felici, M., additional, Filwett, R. J., additional, Fischer, G., additional, Gershman, D. J., additional, Gkioulidou, M., additional, Greathouse, T. K., additional, Griton, L., additional, Gritsevich, M., additional, Hibbitts, K., additional, Hospodarsky, G., additional, Hue, V., additional, Hunt, G., additional, Huybrighs, H. L. F., additional, Imai, M., additional, Jackman, C. M., additional, Jasinski, J. M., additional, Jia, X., additional, Jun, I., additional, Kotova, A., additional, Kurth, W. S., additional, Lamy, L., additional, Lazio, J., additional, Lejosne, S., additional, Louis, C., additional, Masters, A., additional, Mauk, B., additional, Madanian, H., additional, Mandt, K. E., additional, Jr., R. McNutt,, additional, Melin, H., additional, Miller, S., additional, Moore, L., additional, Nenon, Q., additional, Neubauer, F. M., additional, Nordheim, T., additional, Palmaerts, B., additional, Paranicas, C., additional, Phipps, P., additional, Regoli, L., additional, Retherford, K., additional, Roth, L., additional, Roussos, E., additional, Runyon, K. D., additional, Rymer, A., additional, Saur, J., additional, Santos-Costa, D., additional, Shprits, Y. Y., additional, Spilker, L. J., additional, Stallard, T., additional, Smirnov, A. G., additional, Soderlund, K., additional, Stanley, S., additional, Sulaiman, A. H., additional, Szalay, J. R., additional, Turner, D. L., additional, Vines, S., additional, Wang, L., additional, Weiss, B., additional, Wicht, J., additional, Wilson, R. J., additional, and Woodfield, E., additional

Published
2021
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14. Solar System Ice Giants: Exoplanets in our Backyard

Author

Rymer, A, Mandt, K, Hurley, D, Lisse, C, Izenberg, N, Smith, HT, Westlake, J, Bunce, E, Arridge, C, Masters, A, Hofstadter, M, Simon, A, Brandt, P, Clark, G, Cohen, I, Allen, R, Vine, S, Hansen, K, Hospodarsky, G, Kurth, W, Romani, P, Lamy, L, Zarka, P, Cao, H, Paty, C, Hedman, M, Roussos, E, Cruikshank, D, Farrell, W, Fieseler, P, Coates, A, Yelle, R, Parkinson, C, Militzer, B, Grodent, D, Kollmann, P, McNutt, R, André, N, Strange, N, Barnes, J, Dones, L, Denk, T, Rathbun, J, Lunine, J, Desai, R, Cochrane, C, Sayanagi, KM, Postberg, F, Ebert, R, Hill, T, Mueller-Wodarg, I, Regoli, L, Pontius, D, Stanley, S, Greathouse, T, Saur, J, Marouf, E, Bergman, J, Higgins, C, Johnson, R, Thomsen, M, Soderlund, K, Jia, X, Wilson, R, Englander, J, Burch, J, Nordheim, T, Grava, C, Baines, K, Quick, L, Russell, C, Cravens, T, Cecconi, B, Aslam, S, Bray, V, Garcia-Sage, K, Richardson, J, Clark, J, Hsu, S, Achterberg, R, Sergis, N, Paganelli, F, Kempf, S, Orton, G, Portyankina, G, Jones, G, Economou, T, Livengood, T, Krimigi, S, Szalay, J, Jackman, C, Valek, P, Lecacheux, A, Colwell, J, Jasinski, J, Tosi, F, Sulaiman, A, Galand, M, Kotova, A, Khurana, K, Kivelson, M, Strobel, D, Radiota, A, Estrada, P, Livi, S, Azari, A, Yates, J, Allegrini, F, Vogt, M, Felici, M, Luhmann, J, Filacchione, G, and Moore, L

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Physics::Space Physics, astro-ph.EP, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics
Abstract

Future remote sensing of exoplanets will be enhanced by a thorough investigation of our solar system Ice Giants (Neptune-size planets). What can the configuration of the magnetic field tell us (remotely) about the interior, and what implications does that field have for the structure of the magnetosphere; energy input into the atmosphere, and surface geophysics (for example surface weathering of satellites that might harbour sub-surface oceans). How can monitoring of auroral emission help inform future remote observations of emission from exoplanets? Our Solar System provides the only laboratory in which we can perform in-situ experiments to understand exoplanet formation, dynamos, systems and magnetospheres.

Published
2019

15. Titan's Variable Ionosphere During the T118 and T119 Cassini Flybys

Author

Edberg, Niklas J. T., Vigren, Erik, Snowden, D., Regoli, L. H., Shebanits, Oleg, Wahlund, Jan-Erik, Andrews, David J., Bertucci, C., Cui, J., Edberg, Niklas J. T., Vigren, Erik, Snowden, D., Regoli, L. H., Shebanits, Oleg, Wahlund, Jan-Erik, Andrews, David J., Bertucci, C., and Cui, J.

Abstract

We report on unusual dynamics in Titan's ionosphere as a significant difference in ionospheric electron density is observed between the T118 and T119 Cassini nightside flybys. Two distinct nightside electron density peaks were present during T118, at 1,150 and 1,200km, and the lowest density ever observed in Titan's ionosphere at altitudes 1,000-1,350km was during T118. These flybys were quite similar in geometry, Saturn local time, neutral density, extreme ultraviolet flux, and ambient magnetic field conditions. Despite this, the Radio and Plasma Waves/Langmuir Probe measured a density difference up to a factor of 6 between the passes. The overall difference was present and similar during both inbound and outbound legs. By ruling out other factors, we suggest that an exceptionally low rate of particle impact ionization in combination with dynamics in the ionosphere is the explanation for the observations. Plain Language Summary Using the Cassini satellite in orbit around Saturn, we make measurements during two close passes of the moon Titan. We observe how the electron density in the uppermost part of the moon's atmosphere-the ionosphere-changes drastically from one pass to the next. We also observe unexpectedly high peaks of electron density in a specific altitude range during the first pass. The findings are attributed to low influx of charged particles from Saturn's magnetosphere as well as to increased dynamics of the plasma in the ionosphere. The study emphasizes the complexity of the physical process at play at the moon and aims at gaining further understanding of this environment.

Published
2018
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16. Temporal Evolution of O+Population in the Near‐Earth Plasma Sheet During Geomagnetic Storms as Observed by the Magnetospheric Multiscale Mission

Author

Regoli, L. H., Gkioulidou, M., Ohtani, S., Raptis, S., Mouikis, C. G., Kistler, L. M., Cohen, I. J., and Fuselier, S. A.

Abstract

During geomagnetic storms, the increase in energy input into the ionosphere in the form of Poynting flux and electron precipitation leads to an enhanced ionospheric outflow that results in an increase of the O+content in the magnetosphere. Using different missions and instrumentation, two main ionospheric sources have been identified for the oxygen ions reaching the inner magnetosphere during geomagnetic storms: the dayside cusp, and the night side auroral region. Evidence of both pathways have been presented in the literature. However, the relative contribution of each of these pathways to the enhancement of O+observed in near‐Earth plasma sheet, as well as the dynamics involved during the development of geomagnetic storms remains an open question. Here, we present the first statistical study to date to address this question, in the form of a superposed epoch analysis of O+and H+moments obtained by the Magnetospheric Multiscale (MMS) mission throughout the main phase of 90 geomagnetic storms with a minimum SYM‐H of at least −50 nT. The results show a clear increase in the oxygen density in the near‐Earth plasma sheet, with values further from Earth remaining low. Temperature values for both species show an increase with the progress of the storms. These results combined suggest that, during the main phase of geomagnetic storms, most of the oxygen ions observed in the near‐Earth plasma sheet are traveling directly from the nightside auroral region. Superposed epoch analysis shows dynamic evolution of O+ions during geomagnetic stormsSignificant enhancement of the O+‐to‐H+number density ratio observed at radial distances less than 12 REScalar temperature for both species show the arrival of heated ions far from Earth throughout the analyzed period Superposed epoch analysis shows dynamic evolution of O+ions during geomagnetic storms Significant enhancement of the O+‐to‐H+number density ratio observed at radial distances less than 12 RE Scalar temperature for both species show the arrival of heated ions far from Earth throughout the analyzed period

Published
2024
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21. Cassini CAPS Identification of Pickup Ion Compositions at Rhea

Author

Desai, R. T., primary, Taylor, S. A., additional, Regoli, L. H., additional, Coates, A. J., additional, Nordheim, T. A., additional, Cordiner, M. A., additional, Teolis, B. D., additional, Thomsen, M. F., additional, Johnson, R. E., additional, Jones, G. H., additional, Cowee, M. M., additional, and Waite, J. H., additional

Published
2018
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23. Access of energetic particles to Titan's exobase: A study of Cassini's T9 flyby

Author

Regoli, L. H., Roussos, E., Feyerabend, M., Jones, G. H., Krupp, N., Coates, A. J., Simon, S., Motschmann, U., Dougherty, M. K., Regoli, L. H., Roussos, E., Feyerabend, M., Jones, G. H., Krupp, N., Coates, A. J., Simon, S., Motschmann, U., and Dougherty, M. K.

Abstract

We study how the local electromagnetic disturbances introduced by Titan affect the ionization rates of the atmosphere. For this, we model the precipitation of energetic particles, specifically hydrogen and oxygen ions with energies between 1 keV and 1 MeV, into Titan's exobase for the specific magneto spheric configuration of the T9 flyby. For the study, a particle tracing software package is used which consists of an integration of the single particle Lorentz force equation using a 4th order Runge-Kutta numerical Method. For the electromagnetic disturbances, the output of the A.I.K.E.F. hybrid code (kinetic ions, fluid electrons) is used, allowing the possibility of analyzing the disturbances and asymmetries in the access of energetic particles originated by their large gyroradii. By combining these methods, 2D maps showing the access of each set of particles were produced. We show that the access of different particles is largely dominated by their gyroradii, with the complexity of the maps increasing with decreasing gyroradius, due to the larger effect that local disturbances introduced by the presence of the moon have in the trajectory of the particles with lower energies. We also show that for particles with gyroradii much larger than the moon's radius, simpler descriptions of the electromagnetic environment can reproduce similar results to those obtained when using the full hybrid simulation description, with simple north-south fields being sufficient to reproduce the hybrid code results for O+ ions with energies larger than 10 keV but not enough to reproduce those for H+ ions at any of the energies covered in the present study. Finally, by combining the maps created with upstream plasma flow measurements by the MIMI/CHEMS instrument, we are able to estimate normalized fluxes arriving at different selected positions of the moon's exobase. We then use these fluxes to calculate energy deposition and non dissociative N-2 ionization rates for precipitating O+ and

Published
2016

29. New Terthiophene Derivatives for Ultrahigh Molecular Weight Polyethylene-Based Absorption Polarizers

Author

Tirelli, N., Amabile, S., Cellai, C., Pucci, A., Regoli, L., Ruggeri, G., and Ciardelli, F.

Abstract

Several new terthiophene-based, highly anisotropic chromophores were synthesized and dispersed in ultrahigh molecular weight polyethylene (UHMWPE). The chromophores were axially oriented by drawing the polymer matrix and showed an extremely pronounced dichroic behavior. In a pseudo-affine deformation scheme the dyes did well approximate the ultimate properties in terms of molecular orientation; on the other hand, the observed thermochromism and other experimental evidence indicated the persistence of a phase segregation from the polymer matrix.

Published
2001

31. LUNAR VERTEX: A PRISM MISSION TO A MAGNETIC ANOMALY.

Author

Blewett, D. T., Halekas, J., Ho, G., Greenhagen, B. T., Anderson, B. J., Regoli, L., Vines, S. K., Jahn, J.-M., Kollmann, P., Denevi, B. W., Meyer, H. M., Klima, R. L., Cahill, J. T. S., Hood, L. L., Tikoo, S., Zou, X.-D., Fatemi, S., Lemelin, M., Wieczorek, M. A., and Boldt, J. D.

Subjects
SCIENTIFIC apparatus & instruments, SPACE sciences, GEOMAGNETISM, PLASMA physics, PRISMS
Published
2021

32. Tre ritagli di Nicolò di Giacomo e l’iconografia del beato Simone da Todi

Author

BENATI, DANIELE, J.J.G. Alexander, A.E. Andriolo, L. Armstrong, F. Avril, G. Baldissin Molli, U. Bauer-Eberhardt, M. Bollati, F. L. Bossetto, A.R. Calderoni Masetti, G. Castiglioni, F. Crivello, G. Dalli Regoli, L. Dal Poz, A. De Floriani, A. De Marchi, A. De Nicolò Salmazo, A. Dillon Bussi, T. D’Urso, H.J. Eberhardt, F. Flores d’Arcais, T. Franco, S. Fumian, I. Furlan, C. Guarnieri, L. Humphrey, H. Katalin Szépe, S. L’Engle, F. Lollini, S. Maddalo, F. Manzari, S. Marcon, M. Medica, M. Minazzato, P.L. Mulas, X. Muratova, A. Nante, M. Natale, L. Novello, L. Nuvoloni, G. Orofino, S. Panayotova, A. Perriccioli Saggese, S. Pettenati, M. Pietrogiovanna, E. Ponzi, A. Putaturo Donati Murano, M. Rossi, L. Speciale, E.A. Talamo, F. Toniolo, G. Toscano, G. Valenzano, Toniolo, F. Toscano G., and BENATI D.

Subjects
ICONOGRAFIA AGOSTINIANA, NICOLO' DI GIACOMO, MINIATURA BOLOGNESE
Abstract

Vengono rese note alcune miniature ritagliate di Nicolò di Giacomo, riconducibili ai corali di San Giacomo Maggiore a Bologna. Nell'occasione si approfondisce l'iconografia dell'agostiniano Simone da Todi, presente in uno dei ritagli.

Published
2012

33. The bioconcentration and bioaccumulation factors for molybdenum in the aquatic environment from natural environmental concentrations up to the toxicity boundary.

Author

Regoli L, Van Tilborg W, Heijerick D, Stubblefield W, and Carey S

Subjects
Animals, Environmental Exposure adverse effects, Food Chain, Humans, Molybdenum analysis, Molybdenum toxicity, Oncorhynchus mykiss, Fishes, Industrial Waste, Molybdenum metabolism, Water Pollutants, Chemical toxicity
Abstract

In a regulatory context, bioaccumulation or bioconcentration factors are used for considering secondary poisoning potential and assessing risks to human health via the food chain. In this paper, literature data on the bioaccumulation of molybdenum in the aquatic organisms are reviewed and assessed for relevance and reliability. The data available in the literature were generated at exposure concentrations below those recommended in the REACH registration dossiers for molybdenum compounds i.e. PNEC(freshwater) 12.7 mg Mo/L. To address possible environmental concerns at regulatorily-relevant molybdenum concentrations, both a field study and a laboratory study were conducted. In the field study, whole body and organ-specific molybdenum levels were evaluated in fish (eel, stickleback, perch, carp bream, roach) held in the discharge water collector tanks of a molybdenum processing plant, containing a mean measured molybdenum level of 1.03 mg Mo/L. In the laboratory study, rainbow trout were exposed to two different nominal molybdenum levels (1.0 and 12.7 mg Mo/L), for 60 days followed by a 60-day depuration period. Whole body concentrations in rainbow trout during the exposure period were between <0.20 and 0.53 mg Mo/L. Muscle tissue molybdenum concentrations in fish taken from both experiments remained below 0.2mg/kg dry wt. These studies show an inverse relationship between exposure concentration and bioconcentration or bioaccumulation factor for molybdenum. In aquatic organisms, and in fish in particular, internal molybdenum concentrations are maintained in the presence of variation in external molybdenum concentrations. These observations must be considered when evaluating potential risks associated with the bioconcentration and/or bioaccumulation of molybdenum in the aquatic environment., (Copyright © 2012. Published by Elsevier B.V.)

Published
2012
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