425 research outputs found

    Neuron numbers increase in the human amygdala from birth to adulthood, but not in autism.

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    Remarkably little is known about the postnatal cellular development of the human amygdala. It plays a central role in mediating emotional behavior and has an unusually protracted development well into adulthood, increasing in size by 40% from youth to adulthood. Variation from this typical neurodevelopmental trajectory could have profound implications on normal emotional development. We report the results of a stereological analysis of the number of neurons in amygdala nuclei of 52 human brains ranging from 2 to 48 years of age [24 neurotypical and 28 autism spectrum disorder (ASD)]. In neurotypical development, the number of mature neurons in the basal and accessory basal nuclei increases from childhood to adulthood, coinciding with a decrease of immature neurons within the paralaminar nucleus. Individuals with ASD, in contrast, show an initial excess of amygdala neurons during childhood, followed by a reduction in adulthood across nuclei. We propose that there is a long-term contribution of mature neurons from the paralaminar nucleus to other nuclei of the neurotypical human amygdala and that this growth trajectory may be altered in ASD, potentially underlying the volumetric changes detected in ASD and other neurodevelopmental or neuropsychiatric disorders

    Geochemical and biochemical evidence of lake overturn and fish-kill at Lake Averno, Italy.

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    Lake Averno is situated in the homonymous crater in the northwestern sector of the Campi Flegrei active volcanic system in Campania region, Italy. In February 2005 a fish kill event was observed in the lake, prompting a geochemical survey to ascertain the possible cause. In February 2005 a geochemical survey revealed that the lake water was unstratified chemically and isotopically, presumable, as a result of lake overturn. This fish-kill phenomenon was recorded at least two other times in the past. In contrast to the February 2005 results, data collected in October 2005, shows the Lake Averno to be stratified, with an oxic epilimnion (surface to 6 m) and an anoxic hypolimnion (6 m to lake bottom at about 33 m). Chemical and isotopic composition of Lake Averno waters suggests an origin by mixing of shallow waters with a Na-Cl hydrothermal component coupled with an active evaporation process. The isotopic composition of Dissolved Inorganic Carbon, as well as the composition of the non-reactive dissolved gas species again supports the occurrence of this mixing process. Decreasing levels of SO4 and increasing levels of H2S and CH4 contents in lake water with depth, strongly suggests anaerobic bacterial processes are occurring through decomposition of organic matter under anoxic conditions in the sediment and in the water column. Sulfate reduction and methanogenesis processes coexist and play a pivotal role in the anaerobic environment of the Lake Averno. The sulfate reducing bacterial activity has been estimated in the range of 14-22 μmol.m-2.day-1. Total gas pressure of dissolved gases ranges between 800 and 1400 mbar, well below the hydrostatic pressure throughout the water column, excluding the possibility, at least at the survey time, of a limnic eruption. Vertical changes in the density of lake waters indicate that overturn may be triggered by cooling of epilimnetic waters below 7°C. This is a possible phenomenon in winter periods if atmospheric temperatures remain frosty for enough time, as occurred in February 2005. The bulk of these results strongly support the hypothesis that fish kill was caused by a series of events that began with the cooling of the epilimnetic waters with breaking of the thermal stratification, followed by lake overturn and the rise of toxic levels of H2S from the reduced waters near the lake bottom

    New Approximation and Calibration Methods to Provide Routine Real-Time Polarimetry on JET

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    A shallow-layer model for heavy gas dispersion from natural sources: Application and hazard assessment at Caldara di Manziana, Italy

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    Several nonvolcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in the presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow-layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment by evaluating where and when lethal concentrations for humans and animals are reached

    Long term variations at Campi Flegrei (Italy) volcanic system highlighted by the monitoring of hydrothermal activity

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    Long time-series of chemical composition of fumaroles and of soil CO2 flux reveal that important variations in the activity of Solfatara fumarolic field, the most important hydrothermal site of Campi Flegrei, occurred in the 2000- 2008 period. A continuous increase of the CO2 concentration and a general decrease of the CH4 concentration are interpreted as the consequence of the increment of the relative amount of magmatic fluids, rich in CO2 and poor in CH4, hosted by the hydrothermal system. Contemporaneously the H2O-CO2-He-N2 gas system shows remarkable compositional variations in the samples collected after July 2000 with respect to the previous ones, indicating the progressive arrival at the surface of a magmatic component different from that involved in the 1983-84 bradyseism. The change starts in 2000 concurrently with the occurrence of relatively deep long periods seismic events which, in our interpretation, were the indicator of the opening of an easy pathway for the transfer of magmatic fluids towards the shallower, brittle domain hosting the hydrothermal system. Since 2000 this magmatic gas source is active and causes ground deformations, seismicity as well as the expansion of the area interested by diffuse soil degassing of deeply derived CO2

    A shallow layer model for heavy gas dispersion from natural sources: application and hazard assessment at Caldara di Manziana, Italy.

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    Several non-volcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment, by evaluating where and when lethal concentrations for humans and animal are reached.Several non-volcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment, by evaluating where and when lethal concentrations for humans and animal are reached.Several non-volcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment, by evaluating where and when lethal concentrations for humans and animal are reached.Several non-volcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment, by evaluating where and when lethal concentrations for humans and animal are reached.Several non-volcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment, by evaluating where and when lethal concentrations for humans and animal are reached

    Escalating CO2 degassing at the Pisciarelli fumarolic system, and implications for the ongoing Campi Flegrei unrest

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    This short communication aims at providing an updated report on degassing activity and ground deformation variations observed during the ongoing (2012–2019) Campi Flegrei caldera unrest, with a particular focus on Pisciarelli, currently its most active fumarolic field. We show that the CO2 flux from the main Pisciarelli fumarolic vent (referred as “Soffione”) has increased by a factor > 3 since 2012, reaching in 2018–2019 levels (>600 tons/day) that are comparable to those typical of a medium-sized erupting arc volcano. A substantial widening of the degassing vents and bubbling pools, and a further increase in CO2 concentrations in ambient air (up to 6000 ppm), have also been detected since mid-2018. We interpret this escalating CO2 degassing activity using a multidisciplinary dataset that includes thermodynamically estimated pressures for the source hydrothermal system, seismic and ground deformation data. From this analysis, we show that degassing, deformation and seismicity have all reached in 2018–2019 levels never observed since the onset of the unrest in 2005, with an overall uplift of ~57 cm and ~448 seismic events in the last year. The calculated pressure of the Campi Flegrei hydrothermal system has reached ~44 bar and is rapidly increasing. Our results raise concern on the possible evolution of the Campi Flegrei unrest and reinforce the need for careful monitoring of the degassing activity at Pisciarelli, hopefully with the deployment of additional permanent gas monitoring units

    Electromagnetic turbulent structures: A ubiquitous feature of the edge region of toroidal plasma configurations

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    Electromagnetic features of turbulent filaments, emerging from a turbulent plasma background, have been studied in four different magnetic configurations: the stellarator TJ-II, the Reversed Field Pinch RFX-mod, a device that can be operated also as a ohmic tokamak, and the Simple Magnetized Torus, TORPEX. By applying an analogous diagnostic concept in all cases, direct measurements of both field-aligned current density and vorticity were performed inside the filament. The inter-machine comparison reveals a clear dependence of the filament vorticity upon the local time-averaged E x B flow shear. Furthermore, a wide range of local beta was explored allowing concluding that this parameter plays a fundamental role in the appearance of filament electromagnetic features

    The variable finesse locking technique

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    Virgo is a power recycled Michelson interferometer, with 3 km long Fabry-Perot cavities in the arms. The locking of the interferometer has been obtained with an original lock acquisition technique. The main idea is to lock the instrument away from its working point. Lock is obtained by misaligning the power recycling mirror and detuning the Michelson from the dark fringe. In this way, a good fraction of light escapes through the antisymmetric port and the power build-up inside the recycling cavity is extremely low. The benefit is that all the degrees of freedom are controlled when they are almost decoupled, and the linewidth of the recycling cavity is large. The interferometer is then adiabatically brought on to the dark fringe. This technique is referred to as variable finesse, since the recycling cavity is considered as a variable finesse Fabry-Perot. This technique has been widely tested and allows us to reach the dark fringe in few minutes, in an essentially deterministic way
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