The morphology, texture, grain size and other physicochemical characteristics of pyroclastic material from the first phases of the Puyehue-Cordon Caulle volcanic complex (PCCVC) eruption, (Southern Andes, Chile), can ...The morphology, texture, grain size and other physicochemical characteristics of pyroclastic material from the first phases of the Puyehue-Cordon Caulle volcanic complex (PCCVC) eruption, (Southern Andes, Chile), can be associated to the model recently reported for the magma storage and its ascent conditions. The eruption started June 4th 2011, and the studied volcanic material corresponds to that collected in Argentine territory at different distances from the source, between 4 and 12 June 2011. The explosive-effusive volcanic process of the first days occurred with the simultaneous emplacement of lava flows and the venting of pyroclastic material, ejecting two well differentiated types of particles. The more abundant was constituted by rhyolitic and light color pumice fragments, characterized by a typical vesicular texture, easy fragmentation and absence of occluded crystalline phases. Particles found in minor proportion were dark color, different in shape and texture and rich in Fe and Ti. They seemed to be more effective for the interaction with emitted gases in the upper part of the column, for this reason, they appeared partially covered by condensation products. The ascent conditions of the magma affected its rheological behavior through variations in the degassing, viscosity and fragmentation. On the other hand, distance to the source, depositional time, volcanic evolution and environmental conditions are factors that affect the chemical composition of collected ash. So, the SiO2/FeO ratio not only increases with the distance but also with the deposition time and volcanic activity. The work was done with the aid of several techniques such as a laser-sediment analyzer, X-ray diffraction (XRD), chemical analysis (bulk and surface), SEM microscopy and Raman “microprobe” spectroscopy. On the other hand, the physicochemical behavior of the pyroclastic material allows us to suggest eventual applications.展开更多
Large spontaneous portal-systemic shunts have been occasionally described in patients with cirrhosis. This study was undertaken to assess the prevalence of portal-systemic shunts in patients with cirrhosis with recurr...Large spontaneous portal-systemic shunts have been occasionally described in patients with cirrhosis. This study was undertaken to assess the prevalence of portal-systemic shunts in patients with cirrhosis with recurrent or persistent hepatic encephalopathy (HE) as compared with patients with cirrhosis without HE. Fourteen patients with cirrhosis with recurrent or persistent HE (cases) and 14 patients with cirrhosis without previous or present signs of overt HE matching for age and degree of liver failure (controls) were studied. Each patient underwent neurological assessment and cerebral magnetic resonance (MR) imaging to exclude organic neurological pathological conditions. HE evaluation included psychometric performance (Trail-Making Test A), electroencephalogram (EEG),mental status examination and grading, arterial, venous, and partial pressure of ammonia determination. The presence of portal-systemic shunts was assessed by portal venous phase multidetector-row spiral computed tomography (CT). Large spontaneous portal-systemic shunts were detected in 10 patients with HE and in only 2 patients without HE (71% vs. 14% ; chi square = 9.16; df = 1.0; P = .002). The patients with HE presented ascites (P = .002) and medium/large esophageal varices (P = .02) less frequently than the control group. In conclusion, our study suggests that large spontaneous shunts may often sustain the chronicity of HE; the presence of large shunts should be sought in patients with cirrhosis with recurrent or persistent HE.展开更多
Using the Gegenbauer polynomials and the zonal harmonics functions we give some representation formula of the Green function in the annulus. We apply this result to prove some uniqueness results for some nonlinear ell...Using the Gegenbauer polynomials and the zonal harmonics functions we give some representation formula of the Green function in the annulus. We apply this result to prove some uniqueness results for some nonlinear elliptic problems.展开更多
The space-fractional telegraph equation is analyzed and the Fourier transform of its funda-mental solution is obtained and discussed.A symmetric process with discontinuous trajectories, whose transition function satis...The space-fractional telegraph equation is analyzed and the Fourier transform of its funda-mental solution is obtained and discussed.A symmetric process with discontinuous trajectories, whose transition function satisfies thespace-fractional telegraph equation, is presented. Its limiting behaviour and the connectionwith symmetric stable processes is also examined.展开更多
Porous materials have many applications for laser–matter interaction experiments related to inertial confinement fusion.Obtaining new knowledge about the properties of the laser-produced plasma of porous media is a c...Porous materials have many applications for laser–matter interaction experiments related to inertial confinement fusion.Obtaining new knowledge about the properties of the laser-produced plasma of porous media is a challenging task.In this work,we report,for the first time to the best of our knowledge,the time-dependent measurement of the reflected light of a terawatt laser pulse from the laser-produced plasma of low-Z foam material of overcritical density.The experiments have been performed with the ABC laser,with targets constituted by foam of overcritical density and by solid media of the same chemical composition.We implemented in the MULTI-FM code a model for the light reflection to reproduce and interpret the experimental results.Using the simulations together with the experimental results,we indicate a criterion for estimating the homogenization time of the laser-produced plasma,whose measurement is challenging with direct diagnostic techniques and still not achieved.展开更多
In this paper we consider the Dirichlet problem■where p is a small parameter andΩis a C^(2)bounded domain in R^(2).In[1],the author proves the existence of a m-point blow-up solution u_(p)jointly with its asymptotic...In this paper we consider the Dirichlet problem■where p is a small parameter andΩis a C^(2)bounded domain in R^(2).In[1],the author proves the existence of a m-point blow-up solution u_(p)jointly with its asymptotic behaviour.We compute the Morse index of up in terms of the Morse index of the associated Hamilton function of this problem.In addition,we give an asymptotic estimate for the first 4m eigenvalues and eigenfunctions.展开更多
Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes o...Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal electrons.Such a regime is of paramount importance for inertial confinement fusion(ICF)and in particular for the shock ignition scheme.In this paper we report on an experiment carried out at the Prague Asterix Laser System(PALS)facility to investigate the extent and time history of stimulated Raman scattering(SRS)and two-plasmon decay(TPD)instabilities,driven by the interaction of an infrared laser pulse at an intensity^1.2×1016 W·cm^-2 with a^100μm scalelength plasma produced from irradiation of a flat plastic target.The laser pulse duration(300 ps)and the high value of plasma temperature(~4 ke V)expected from hydrodynamic simulations make these results interesting for a deeper understanding of LPI in shock ignition conditions.Experimental results show that absolute TPD/SRS,driven at a quarter of the critical density,and convective SRS,driven at lower plasma densities,are well separated in time,with absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and persisting all over the tail of the pulse.Side-scattering SRS,driven at low plasma densities,is also clearly observed.Experimental results are compared to fully kinetic large-scale,two-dimensional simulations.Particle-in-cell results,beyond reproducing the framework delineated by the experimental measurements,reveal the importance of filamentation instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of collisionless absorption in the LPI energy balance.展开更多
The interaction of ultra-intense high-power lasers with solid-state targets has been largely studied for the past 20 years as a future compact proton and ion source.Indeed,the huge potential established on the target ...The interaction of ultra-intense high-power lasers with solid-state targets has been largely studied for the past 20 years as a future compact proton and ion source.Indeed,the huge potential established on the target surface by the escaping electrons provides accelerating gradients of TV/m.This process,called target normal sheath acceleration,involves a large number of phenomena and is very difficult to study because of the picosecond scale dynamics.At the SPARC LAB Test Facility,the high-power laser FLAME is employed in experiments with solid targets,aiming to study possible correlations between ballistic fast electrons and accelerated protons.In detail,we have installed in the interaction chamber two different diagnostics,each one devoted to characterizing one beam.The first relies on electro-optic sampling,and it has been adopted to completely characterize the ultrafast electron components.On the other hand,a time-of-flight detector,based on chemical-vapour-deposited diamond,has allowed us to retrieve the proton energy spectrum.In this work,we report preliminary studies about simultaneous temporal resolved measurements of both the first forerunner escaping electrons and the accelerated protons for different laser parameters.展开更多
Self-action nonlinearity is a key aspect either as a foundational element or a detrimental factor of several optical spectroscopies and photonic devices.Supercontinuum generation,wavelength converters,and chirped puls...Self-action nonlinearity is a key aspect either as a foundational element or a detrimental factor of several optical spectroscopies and photonic devices.Supercontinuum generation,wavelength converters,and chirped pulse amplification are just a few examples.The recent advent of Free Electron Lasers(FEL)fostered building on nonlinearity to propose new concepts and extend optical wavelengths paradigms for extreme ultraviolet(EUV)and X-ray regimes.No evidence for intrapulse dynamics,however,has been reported at such short wavelengths,where the light-matter interactions are ruled by the sharp absorption edges of core electrons.Here,we provide experimental evidence for self-phase modulation of femtosec ond FEL pulses,which we exploit for fine self-driven spectral tun ability by interaction with sub-micrometric foils of selected monoatomic materials.Moving the pulse wavelength across the absorption edge,the spectral profile changes from a non-linear spectral blue-shift to a red-shifted broadening.These findings are rationalized account!ng for ultrafast ionization and delayed thermal response of highly excited electrons above and below threshold,respectively.展开更多
The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse mome...The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B(∧0/b→ J/ψ pK-)=(3.17±0.04±0.07±0.34+0.45/-0.28)×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K*(892)0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P+c(→ J/ψp)K-are determined.展开更多
A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13...A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.展开更多
文摘The morphology, texture, grain size and other physicochemical characteristics of pyroclastic material from the first phases of the Puyehue-Cordon Caulle volcanic complex (PCCVC) eruption, (Southern Andes, Chile), can be associated to the model recently reported for the magma storage and its ascent conditions. The eruption started June 4th 2011, and the studied volcanic material corresponds to that collected in Argentine territory at different distances from the source, between 4 and 12 June 2011. The explosive-effusive volcanic process of the first days occurred with the simultaneous emplacement of lava flows and the venting of pyroclastic material, ejecting two well differentiated types of particles. The more abundant was constituted by rhyolitic and light color pumice fragments, characterized by a typical vesicular texture, easy fragmentation and absence of occluded crystalline phases. Particles found in minor proportion were dark color, different in shape and texture and rich in Fe and Ti. They seemed to be more effective for the interaction with emitted gases in the upper part of the column, for this reason, they appeared partially covered by condensation products. The ascent conditions of the magma affected its rheological behavior through variations in the degassing, viscosity and fragmentation. On the other hand, distance to the source, depositional time, volcanic evolution and environmental conditions are factors that affect the chemical composition of collected ash. So, the SiO2/FeO ratio not only increases with the distance but also with the deposition time and volcanic activity. The work was done with the aid of several techniques such as a laser-sediment analyzer, X-ray diffraction (XRD), chemical analysis (bulk and surface), SEM microscopy and Raman “microprobe” spectroscopy. On the other hand, the physicochemical behavior of the pyroclastic material allows us to suggest eventual applications.
文摘Large spontaneous portal-systemic shunts have been occasionally described in patients with cirrhosis. This study was undertaken to assess the prevalence of portal-systemic shunts in patients with cirrhosis with recurrent or persistent hepatic encephalopathy (HE) as compared with patients with cirrhosis without HE. Fourteen patients with cirrhosis with recurrent or persistent HE (cases) and 14 patients with cirrhosis without previous or present signs of overt HE matching for age and degree of liver failure (controls) were studied. Each patient underwent neurological assessment and cerebral magnetic resonance (MR) imaging to exclude organic neurological pathological conditions. HE evaluation included psychometric performance (Trail-Making Test A), electroencephalogram (EEG),mental status examination and grading, arterial, venous, and partial pressure of ammonia determination. The presence of portal-systemic shunts was assessed by portal venous phase multidetector-row spiral computed tomography (CT). Large spontaneous portal-systemic shunts were detected in 10 patients with HE and in only 2 patients without HE (71% vs. 14% ; chi square = 9.16; df = 1.0; P = .002). The patients with HE presented ascites (P = .002) and medium/large esophageal varices (P = .02) less frequently than the control group. In conclusion, our study suggests that large spontaneous shunts may often sustain the chronicity of HE; the presence of large shunts should be sought in patients with cirrhosis with recurrent or persistent HE.
基金supported by PRIN-2009-WRJ3W7 grantsupported by Basileus scholarship programme
文摘Using the Gegenbauer polynomials and the zonal harmonics functions we give some representation formula of the Green function in the annulus. We apply this result to prove some uniqueness results for some nonlinear elliptic problems.
基金Project supported by the National Natural Science Foundation of China (No. 10071014).
文摘The space-fractional telegraph equation is analyzed and the Fourier transform of its funda-mental solution is obtained and discussed.A symmetric process with discontinuous trajectories, whose transition function satisfies thespace-fractional telegraph equation, is presented. Its limiting behaviour and the connectionwith symmetric stable processes is also examined.
基金funded from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement number 633053。
文摘Porous materials have many applications for laser–matter interaction experiments related to inertial confinement fusion.Obtaining new knowledge about the properties of the laser-produced plasma of porous media is a challenging task.In this work,we report,for the first time to the best of our knowledge,the time-dependent measurement of the reflected light of a terawatt laser pulse from the laser-produced plasma of low-Z foam material of overcritical density.The experiments have been performed with the ABC laser,with targets constituted by foam of overcritical density and by solid media of the same chemical composition.We implemented in the MULTI-FM code a model for the light reflection to reproduce and interpret the experimental results.Using the simulations together with the experimental results,we indicate a criterion for estimating the homogenization time of the laser-produced plasma,whose measurement is challenging with direct diagnostic techniques and still not achieved.
文摘In this paper we consider the Dirichlet problem■where p is a small parameter andΩis a C^(2)bounded domain in R^(2).In[1],the author proves the existence of a m-point blow-up solution u_(p)jointly with its asymptotic behaviour.We compute the Morse index of up in terms of the Morse index of the associated Hamilton function of this problem.In addition,we give an asymptotic estimate for the first 4m eigenvalues and eigenfunctions.
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure activity within the ECs seventh Framework Programfunding from the Euratom research and training programme 2014–2018 under grant agreement No. 633053+4 种基金partially supported by the project ELITAS (ELI Tools for Advanced Simulation) CZ.02.1.01/0.0/0.0/16 013/0001793HIFI (High Field Initiative, CZ.02.1.01/0.0/0.0/15 003/0000449)ADONIS (Advanced research using high-intensity laser produced photons and particles, CZ.02.1.01/0.0/0.0/16 019/0000789)ELITAS (ELI Tools for Advanced Simulations,CZ.02.1.01/0.0/0.0/16 013/0001793)financial support from the Czech Ministry of Education, Youth and Sports within grants LTT17015, LM2015083, and CZ.02.1.01/0.0/0.0/16 013/0001552 (EF16 013/0001552)
文摘Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal electrons.Such a regime is of paramount importance for inertial confinement fusion(ICF)and in particular for the shock ignition scheme.In this paper we report on an experiment carried out at the Prague Asterix Laser System(PALS)facility to investigate the extent and time history of stimulated Raman scattering(SRS)and two-plasmon decay(TPD)instabilities,driven by the interaction of an infrared laser pulse at an intensity^1.2×1016 W·cm^-2 with a^100μm scalelength plasma produced from irradiation of a flat plastic target.The laser pulse duration(300 ps)and the high value of plasma temperature(~4 ke V)expected from hydrodynamic simulations make these results interesting for a deeper understanding of LPI in shock ignition conditions.Experimental results show that absolute TPD/SRS,driven at a quarter of the critical density,and convective SRS,driven at lower plasma densities,are well separated in time,with absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and persisting all over the tail of the pulse.Side-scattering SRS,driven at low plasma densities,is also clearly observed.Experimental results are compared to fully kinetic large-scale,two-dimensional simulations.Particle-in-cell results,beyond reproducing the framework delineated by the experimental measurements,reveal the importance of filamentation instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of collisionless absorption in the LPI energy balance.
文摘The interaction of ultra-intense high-power lasers with solid-state targets has been largely studied for the past 20 years as a future compact proton and ion source.Indeed,the huge potential established on the target surface by the escaping electrons provides accelerating gradients of TV/m.This process,called target normal sheath acceleration,involves a large number of phenomena and is very difficult to study because of the picosecond scale dynamics.At the SPARC LAB Test Facility,the high-power laser FLAME is employed in experiments with solid targets,aiming to study possible correlations between ballistic fast electrons and accelerated protons.In detail,we have installed in the interaction chamber two different diagnostics,each one devoted to characterizing one beam.The first relies on electro-optic sampling,and it has been adopted to completely characterize the ultrafast electron components.On the other hand,a time-of-flight detector,based on chemical-vapour-deposited diamond,has allowed us to retrieve the proton energy spectrum.In this work,we report preliminary studies about simultaneous temporal resolved measurements of both the first forerunner escaping electrons and the accelerated protons for different laser parameters.
基金the European Union's Horizon 2020 research and innovation programme Graphene Flagship tinder grant agreement No 881603 and from PRIN 2017 Project 201795SBA3 HARVEST.
文摘Self-action nonlinearity is a key aspect either as a foundational element or a detrimental factor of several optical spectroscopies and photonic devices.Supercontinuum generation,wavelength converters,and chirped pulse amplification are just a few examples.The recent advent of Free Electron Lasers(FEL)fostered building on nonlinearity to propose new concepts and extend optical wavelengths paradigms for extreme ultraviolet(EUV)and X-ray regimes.No evidence for intrapulse dynamics,however,has been reported at such short wavelengths,where the light-matter interactions are ruled by the sharp absorption edges of core electrons.Here,we provide experimental evidence for self-phase modulation of femtosec ond FEL pulses,which we exploit for fine self-driven spectral tun ability by interaction with sub-micrometric foils of selected monoatomic materials.Moving the pulse wavelength across the absorption edge,the spectral profile changes from a non-linear spectral blue-shift to a red-shifted broadening.These findings are rationalized account!ng for ultrafast ionization and delayed thermal response of highly excited electrons above and below threshold,respectively.
基金Supported by CERN and national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)NSFC(China)+17 种基金CNRS/IN2P3(France)BMBF,DFG,HGF and MPG(Germany)INFN(Italy)FOM and NWO(The Netherlands)MNi SW and NCN(Poland)MEN/IFA(Romania)Min ES and FANO(Russia)Min ECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA)supported by IN2P3(France),KIT and BMBF(Germany),INFN(Italy),NWOSURF(The Netherlands),PIC(Spain),Grid PP(United Kingdom)support from EPLANET,Marie Sk lodowska-Curie ActionsERC(European Union),Conseil général de Haute-Savoie,Labex ENIGMASS and OCEVU,RégionAuvergne(France),RFBR(Russia),Xunta GalGENCAT(Spain),Royal Society and Royal Commission for the Exhibition of 1851(United Kingdom)
文摘The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B(∧0/b→ J/ψ pK-)=(3.17±0.04±0.07±0.34+0.45/-0.28)×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K*(892)0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P+c(→ J/ψp)K-are determined.
基金support from CERN and from the national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)MOST and NSFC(China)+11 种基金CNRS/IN2P3(France)BMBF,DFG and MPG(Germany)INFN(Italy)KWO(Netherlands)MNiSW and NCN(Poland)MEN/IFA(Romania)MinES and FASO(Russia)MinECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA).
文摘A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.