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F Zuccarello - One of the best experts on this subject based on the ideXlab platform.
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observational evidence of torus instability as Trigger Mechanism for coronal mass ejections the 2011 august 4 filament eruption
The Astrophysical Journal, 2014Co-Authors: F Zuccarello, Daniel B Seaton, M Mierla, Stefaan Poedts, Laurel A Rachmeler, P RomanoAbstract:Solar filaments are magnetic structures often observed in the solar atmosphere and consist of plasma that is cooler and denser than their surroundings. They are visible for days—even weeks—which suggests that they are often in equilibrium with their environment before disappearing or erupting. Several eruption models have been proposed that aim to reveal what Mechanism causes (or Triggers) these solar eruptions. Validating these models through observations represents a fundamental step in our understanding of solar eruptions. We present an analysis of the observation of a filament eruption that agrees with the torus instability model. This model predicts that a magnetic flux rope embedded in an ambient field undergoes an eruption when the axis of the flux rope reaches a critical height that depends on the topology of the ambient field. We use the two vantage points of theSolar Dynamics Observatory (SDO) and the Solar TErrestrial RElations Observatory to reconstruct the three-dimensional shape of the filament, to follow its morphological evolution, and to determine its height just before eruption. The magnetograms acquired by SDO/Helioseismic and Magnetic Imager are used to infer the topology of the ambient field and to derive the critical height for the onset of the torus instability. Our analysis shows that the torus instability is the Trigger of the eruption. We also find that some pre-eruptive processes, such as magnetic reconnection during the observed flares and flux cancellation at the neutral line, facilitated the eruption by bringing the filament to a region where the magnetic field was more vulnerable to the torus instability.
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observational evidence of torus instability as Trigger Mechanism for coronal mass ejections the 2011 august 4 filament eruption
arXiv: Solar and Stellar Astrophysics, 2014Co-Authors: F Zuccarello, Daniel B Seaton, M Mierla, Stefaan Poedts, Laurel A Rachmeler, P RomanoAbstract:Solar filaments are magnetic structures often observed in the solar atmosphere and consist of plasma that is cooler and denser than their surroundings. They are visible for days -- and even weeks -- which suggests that they are often in equilibrium with their environment before disappearing or erupting. Several eruption models have been proposed that aim to reveal what Mechanism causes (or Triggers) these solar eruptions. Validating these models through observations represents a fundamental step in our understanding of solar eruptions. We present an analysis of the observation of a filament eruption that agrees with the torus instability model. This model predicts that a magnetic flux rope embedded in an ambient field undergoes an eruption when the axis of the flux rope reaches a critical height that depends on the topology of the ambient field. We use the two vantage points of SDO and STEREO to reconstruct the three-dimensional shape of the filament, to follow its morphological evolution and to determine its height just before eruption. The magnetograms acquired by SDO/HMI are used to infer the topology of the ambient field and to derive the critical height for the onset of the torus instability. Our analysis shows that the torus instability is the Trigger of the eruption. We also find that some pre-eruptive processes, such as magnetic reconnection during the observed flares and flux cancellation at the neutral line, facilitated the eruption by bringing the filament to a region where the magnetic field was more vulnerable to the torus instability.
Cecile Breyton - One of the best experts on this subject based on the ideXlab platform.
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bacteriophage t5 tail tube structure suggests a Trigger Mechanism for siphoviridae dna ejection
Nature Communications, 2017Co-Authors: Charlesadrien Arnaud, Corinne Vives, S Engilberge, Pascale Boulanger, Maria Bacia, Eric Girard, Gregory Effantin, Guy Schoehn, Cecile BreytonAbstract:The vast majority of phages, bacterial viruses, possess a tail ensuring host recognition, cell wall perforation and safe viral DNA transfer from the capsid to the host cytoplasm. Long flexible tails are formed from the tail tube protein (TTP) polymerised as hexameric rings around and stacked along the tape measure protein (TMP). Here, we report the crystal structure of T5 TTP pb6 at 2.2 A resolution. Pb6 is unusual in forming a trimeric ring, although structure analysis reveals homology with all classical TTPs and related tube proteins of bacterial puncturing devices (type VI secretion system and R-pyocin). Structures of T5 tail tubes before and after interaction with the host receptor were determined by cryo-electron microscopy at 6 A resolution. Comparison of these two structures reveals that host-binding information is not propagated to the capsid through conformational changes in the tail tube, suggesting a role of the TMP in this information transduction process. Host cell recognition is mediated by the phage tail tip proteins, which then Triggers viral genome delivery via the phage tail. Here, the authors combine crystallography and cryoEM to structurally characterise the bacteriophage T5 tail tube structure before and after interaction with its host receptor.
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Bacteriophage T5 tail tube structure suggests a Trigger Mechanism for Siphoviridae DNA ejection
Nature Publishing Group, 2017Co-Authors: Charlesadrien Arnaud, Corinne Vives, S Engilberge, Pascale Boulanger, Maria Bacia, Eric Girard, Gregory Effantin, Guy Schoehn, Cecile BreytonAbstract:Host cell recognition is mediated by the phage tail tip proteins, which then Triggers viral genome delivery via the phage tail. Here, the authors combine crystallography and cryoEM to structurally characterise the bacteriophage T5 tail tube structure before and after interaction with its host receptor
Henrik Svensen - One of the best experts on this subject based on the ideXlab platform.
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strike slip faulting as a Trigger Mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia
Marine and Petroleum Geology, 2009Co-Authors: Adriano Mazzini, Anders Nermoen, Marcin Krotkiewski, Yuri Y Podladchikov, Sverre Planke, Henrik SvensenAbstract:Abstract Piercement structures such as hydrothermal vent complexes, pockmarks, and mud volcanoes, are found in various geological settings but are often associated with faults or other fluid-focussing features. This article aims to investigate and understand the Mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike-slip faulting as a Triggering Mechanism for fluidization. For this purpose four different approaches were combined: fieldwork, analogue experiments, and mathematical modeling for brittle and ductile rheologies. The results of this study may be applied to several geological settings, including the newly formed Lusi mud volcano in Indonesia (Mazzini et al., 2007). Lusi became active the 29th of May 2006 on the Java Island. Debates on the Trigger of the eruption rose immediately. Was Lusi Triggered by the reactivation of a fault after a strong earthquake that occurred two days earlier? Or did a neighbouring exploration borehole induce a massive blow-out? Field observations reveal that the Watukosek fault crossing the Lusi mud volcano was reactivated after the 27th of May 2006 earthquake. Ongoing monitoring shows that the frequent seismicity periodically reactivates this fault with synchronous peaks of flow rates from the crater. Our integrated study demonstrates that the critical fluid pressure required to induce sediment deformation and fluidization is dramatically reduced when strike-slip faulting is active. The proposed shear-induced fluidization Mechanism explains why piercement structures such as mud volcanoes are often located along fault zones. Our results support a scenario where the strike-slip movement of the Watukosek fault Triggered the Lusi eruption and synchronous seep activity witnessed at other mud volcanoes along the same fault. The possibility that the drilling contributed to Trigger the eruption cannot be excluded. However, so far, no univocal data support the drilling hypothesis, and a blow-out scenario can neither explain the dramatic changes that affected the plumbing system of numerous seep systems on Java after the 27-05-2006 earthquake. To date (i.e. April 2008) Lusi is still active.
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strike slip faulting as a Trigger Mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia
Marine and Petroleum Geology, 2009Co-Authors: Adriano Mazzini, Anders Nermoen, Marcin Krotkiewski, Yuri Y Podladchikov, Sverre Planke, Henrik SvensenAbstract:Piercement structures such as hydrothermal vent complexes, pockmarks, and mud volcanoes, are found in various geological settings but are often associated with faults or other fluid-focussing features. This article aims to investigate and understand the Mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike-slip faulting as a Triggering Mechanism for fluidization. For this purpose four different approaches were combined: fieldwork, analogue experiments, and math
Charlesadrien Arnaud - One of the best experts on this subject based on the ideXlab platform.
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bacteriophage t5 tail tube structure suggests a Trigger Mechanism for siphoviridae dna ejection
Nature Communications, 2017Co-Authors: Charlesadrien Arnaud, Corinne Vives, S Engilberge, Pascale Boulanger, Maria Bacia, Eric Girard, Gregory Effantin, Guy Schoehn, Cecile BreytonAbstract:The vast majority of phages, bacterial viruses, possess a tail ensuring host recognition, cell wall perforation and safe viral DNA transfer from the capsid to the host cytoplasm. Long flexible tails are formed from the tail tube protein (TTP) polymerised as hexameric rings around and stacked along the tape measure protein (TMP). Here, we report the crystal structure of T5 TTP pb6 at 2.2 A resolution. Pb6 is unusual in forming a trimeric ring, although structure analysis reveals homology with all classical TTPs and related tube proteins of bacterial puncturing devices (type VI secretion system and R-pyocin). Structures of T5 tail tubes before and after interaction with the host receptor were determined by cryo-electron microscopy at 6 A resolution. Comparison of these two structures reveals that host-binding information is not propagated to the capsid through conformational changes in the tail tube, suggesting a role of the TMP in this information transduction process. Host cell recognition is mediated by the phage tail tip proteins, which then Triggers viral genome delivery via the phage tail. Here, the authors combine crystallography and cryoEM to structurally characterise the bacteriophage T5 tail tube structure before and after interaction with its host receptor.
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Bacteriophage T5 tail tube structure suggests a Trigger Mechanism for Siphoviridae DNA ejection
Nature Publishing Group, 2017Co-Authors: Charlesadrien Arnaud, Corinne Vives, S Engilberge, Pascale Boulanger, Maria Bacia, Eric Girard, Gregory Effantin, Guy Schoehn, Cecile BreytonAbstract:Host cell recognition is mediated by the phage tail tip proteins, which then Triggers viral genome delivery via the phage tail. Here, the authors combine crystallography and cryoEM to structurally characterise the bacteriophage T5 tail tube structure before and after interaction with its host receptor
Adriano Mazzini - One of the best experts on this subject based on the ideXlab platform.
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strike slip faulting as a Trigger Mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia
Marine and Petroleum Geology, 2009Co-Authors: Adriano Mazzini, Anders Nermoen, Marcin Krotkiewski, Yuri Y Podladchikov, Sverre Planke, Henrik SvensenAbstract:Abstract Piercement structures such as hydrothermal vent complexes, pockmarks, and mud volcanoes, are found in various geological settings but are often associated with faults or other fluid-focussing features. This article aims to investigate and understand the Mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike-slip faulting as a Triggering Mechanism for fluidization. For this purpose four different approaches were combined: fieldwork, analogue experiments, and mathematical modeling for brittle and ductile rheologies. The results of this study may be applied to several geological settings, including the newly formed Lusi mud volcano in Indonesia (Mazzini et al., 2007). Lusi became active the 29th of May 2006 on the Java Island. Debates on the Trigger of the eruption rose immediately. Was Lusi Triggered by the reactivation of a fault after a strong earthquake that occurred two days earlier? Or did a neighbouring exploration borehole induce a massive blow-out? Field observations reveal that the Watukosek fault crossing the Lusi mud volcano was reactivated after the 27th of May 2006 earthquake. Ongoing monitoring shows that the frequent seismicity periodically reactivates this fault with synchronous peaks of flow rates from the crater. Our integrated study demonstrates that the critical fluid pressure required to induce sediment deformation and fluidization is dramatically reduced when strike-slip faulting is active. The proposed shear-induced fluidization Mechanism explains why piercement structures such as mud volcanoes are often located along fault zones. Our results support a scenario where the strike-slip movement of the Watukosek fault Triggered the Lusi eruption and synchronous seep activity witnessed at other mud volcanoes along the same fault. The possibility that the drilling contributed to Trigger the eruption cannot be excluded. However, so far, no univocal data support the drilling hypothesis, and a blow-out scenario can neither explain the dramatic changes that affected the plumbing system of numerous seep systems on Java after the 27-05-2006 earthquake. To date (i.e. April 2008) Lusi is still active.
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strike slip faulting as a Trigger Mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia
Marine and Petroleum Geology, 2009Co-Authors: Adriano Mazzini, Anders Nermoen, Marcin Krotkiewski, Yuri Y Podladchikov, Sverre Planke, Henrik SvensenAbstract:Piercement structures such as hydrothermal vent complexes, pockmarks, and mud volcanoes, are found in various geological settings but are often associated with faults or other fluid-focussing features. This article aims to investigate and understand the Mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike-slip faulting as a Triggering Mechanism for fluidization. For this purpose four different approaches were combined: fieldwork, analogue experiments, and math
