Habitat evaluation constitutes an important and fundamental step in the management of wildlife populations and conservation policy planning. Geographic information system （GIS） and species presence data provide the ...Habitat evaluation constitutes an important and fundamental step in the management of wildlife populations and conservation policy planning. Geographic information system （GIS） and species presence data provide the means by which such evaluation can be done. Maximum Entropy （MaxEnt） is widely used in habitat suitability modeling due to its power of accuracy and additional descriptive properties To survey snow leopard populations in Qomolangma （Mt. Everest） National Nature Reserve （QNNR）, Xizang （Tibet）, China, we pooled 127 pugmarks, 415 scrape marks, and 127 non-invasive identifications of the animal along line transects and recorded 87 occurrences through camera traps from 2014-2017. We adopted the MaxEnt model to generate a map highlighting the extent of suitable snow leopard habitat in QNNR. Results showed that the accuracy of the MaxEnt model was excellent （mean AUC=0.921）. Precipitation in the driest quarter, ruggedness, elevation, maximum temperature of the warmest month, and annual mean temperature were the main environmental factors influencing habitat suitability for snow leopards, with contribution rates of 20.0%, 14.4%, 13.3%, 8.7%, and 8.2% respectively The suitable habitat area extended for 7 001.93 km^2, representing 22.72% of the whole reserve. The regions bordering Nepal were the main suitable snow leopard habitats and consisted of three separate habitat patches Our findings revealed that precipitation, temperature conditions, ruggedness, and elevations of around 4 000 m a.s.I, influenced snow leopard preferences at the landscape level in QNNR. We advocate further research and cooperation with Nepal to evaluate habitat connectivity and to explore possible proxies of population isolation among these patches. Furthermore, evaluation of subdivisions within the protection zones of QNNR is necessary to improve conservation strategies and enhance protection.展开更多
Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion.The experiment was carried out at the Gekko XII laser...Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion.The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately 3×10^(15)W/cm^(2).Experimental data suggest that high-energy electrons,with temperatures of 20–50 keV and conversion efficiencies ofη<1%,were mainly produced by the damping of electron plasma waves driven by two-plasmon decay(TPD).Stimulated Raman scattering(SRS)is observed in a near-threshold growth regime,producing a reflectivity of approximately 0.01%,and is well described by an analytical model accounting for the convective growth in independent speckles.The experiment reveals that both TPD and SRS are collectively driven by multiple beams,resulting in a more vigorous growth than that driven by single-beam laser intensity.展开更多
A first search for the Ξ_(bc)^(+)J/ψΞ_(c)^(+) decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass...A first search for the Ξ_(bc)^(+)J/ψΞ_(c)^(+) decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the Ξ+bc baryon production cross-section times the branching fraction relative to that of the B+c→J/ψD+s decay at centre-of-mass energies of 8 and 13 TeV, in the Ξ+bc and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV/c, respectively. Upper limits are presented as a function of the Ξ+bc mass and lifetime.展开更多
A search for the rare decays W^(+)→D_(s)^(+)γ and Z→D0γis performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV,corresponding to an integrated luminosity...A search for the rare decays W^(+)→D_(s)^(+)γ and Z→D0γis performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV,corresponding to an integrated luminosity of 2.0fb−1.No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W^(+)→D_(s)^(+)γ and Z→μ+μ−decays as normalization channels.The upper limits are 6.5×10^(−4) and 2.1×10^(−3) at 95% confidence level for the W^(+)→D_(s)^(+)γ and Z→D^(0)γ decay modes,respectively.This is the first reported search for the Z→D^(0)γ decay,while the upper limit on the W+→D+sγbranching fraction improves upon the previous best limit.展开更多
Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China ...Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019.A total of 22 unique genotypes were identified from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis,including 13 males and 9 females.Based on the size of fecal boli,1 animal was a juvenile,9 were subadults,and 12 were adults,indicating that recruitment was limited.The effective population size was small(15.3)but there was no signature of a recent population bottleneck.We observed a low genetic diversity(He=0.46±0.05)and a high level of inbreeding(Fis of 0.43±0.11),suggesting low population viability and high risk of extinction.In total,these elephants lost nearly two thirds(62%)of their habitat in 3 decades.The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population.We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km2 of suitable habitat available.This could allow a population increase of 14 elephants,possibly by translocating individuals from elsewhere in China.Ourfindings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.展开更多
Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual d...Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity.A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide.Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition,the physics of fusion materials and advanced technologies for high-repetitionrate,high-average-power broadband lasers.We believe that the participation of the broader scientific community and the increased engagement of industry,in partnership with research and academic institutions,make most timely the construction of this infrastructure of extreme scientific attractiveness.展开更多
First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark w...First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect.Its mass and width are determined to be 4458:8±2:9t4:7-1:1 MeV and 17:3±6:5t8:0-5:7 MeV,respectively,where the quoted uncertainties are statistical and systematic.The structure is also consistent with being due to two resonances.In addition,the narrow excited■^(-)states,N■(1690)and■(1820),are seen for the first time in a■b^(-)decay,and their masses and widths are measured with improved precision.The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb^(-1),collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV.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
Inflammatory bowel diseases(IBDs), particularly Crohn's disease(CD) and ulcerative colitis(UC), are associated with a variety of extra-intestinal manifestations(EIMs).About 36% of IBD patients have at least one EI...Inflammatory bowel diseases(IBDs), particularly Crohn's disease(CD) and ulcerative colitis(UC), are associated with a variety of extra-intestinal manifestations(EIMs).About 36% of IBD patients have at least one EIM, which most frequently affect the joints, skin, eyes and the biliary tract.The EIMs associated with IBD have a negative impact on patients with UC and CD, and the resolution of most of them parallels that of the active IBD in terms of timing and required therapy;however, the clinical course of EIMs such as axial arthritis, pyoderma gangrenosum, uveitis, and primary sclerosing cholangitis is independent of IBD activity.The peripheral and axial arthritis associated with IBD have traditionally been treated with simple analgesics, non-steroidal anti-inflammatory drugs, steroids, sulfasalazine, methotrexate, local steroid injections and physiotherapy, but the introduction of biological response modifi ers such as tumor necrosis factor-α blockers, has led to further improvements.展开更多
The impact of fuel-ion diffusion in inertial confinement fusion implosions is assessed using nuclear reaction yield ratios and reaction histories.In T3He-gas-filled(with trace D)shock-driven implosions,the observed TT...The impact of fuel-ion diffusion in inertial confinement fusion implosions is assessed using nuclear reaction yield ratios and reaction histories.In T3He-gas-filled(with trace D)shock-driven implosions,the observed TT/T3He yield ratio is∼23lower than expected from temperature scaling.InD3He-gas-filled(with trace T)shock-driven implosions,the timing of theD3He reaction history is∼50 ps earlier than those of the DT reaction histories,and average-ion hydrodynamic simulations cannot reconcile this timing difference.Both experimental observations are consistent with reduced T ions in the burn region as predicted by multi-ion diffusion theory and particle-in-cell simulations.展开更多
We report results and modelling of an experiment performed at the Target Area West Vulcan laser facility,aimed at investigating laser±plasma interaction in conditions that are of interest for the shock ignition s...We report results and modelling of an experiment performed at the Target Area West Vulcan laser facility,aimed at investigating laser±plasma interaction in conditions that are of interest for the shock ignition scheme in inertial confinement fusion(ICF),that is,laser intensity higher than 10^(16) W/cm^(2) impinging on a hot(T>1 keV),inhomogeneous and long scalelength pre-formed plasma.Measurements show a significant stimulated Raman scattering(SRS)backscattering(;%-20%of laser energy)driven at low plasma densities and no signatures of two-plasmon decay(TPD)/SRS driven at the quarter critical density region.Results are satisfactorily reproduced by an analytical model accounting for the convective SRS growth in independent laser speckles,in conditions where the reflectivity is dominated by the contribution from the most intense speckles,where SRS becomes saturated.Analytical and kinetic simulations well reproduce the onset of SRS at low plasma densities in a regime strongly affected by non-linear Landau damping and by filamentation of the most intense laser speckles.The absence of TPD/SRS at higher densities is explained by pump depletion and plasma smoothing driven by filamentation.The prevalence of laser coupling in the low-density profile justifies the low temperature measured for hot electrons(7-12 keV),which is well reproduced by numerical simulations.展开更多
The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in...The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.展开更多
A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No signific...A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No significant signal of the decay is observed and an upper limitof 1.1x 10^(-7)at 90%confidence level is set on the branching fraction.展开更多
The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 T...The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb^(-1).The baryons are reconstructed via their decays to Λ^(+)_(c)π^(-)and E^(+)_(c)π^(-).No significant excess is fbund for invariant masses between 6700 and 7300 MeV/c^(2),in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c.Upper limits are set on the ratio of the Ω^(0)_(bc)and E^(0)_(bc)production cross-section times the branching fraction to Λ^(+)_(c)π^(-)(E^(+)_(c)π^(-))relative to that of the Λ^(0)_(b)(E^(0)_(b))baryon,for different lifetime hypotheses,at 95%confidence level.The upper limits range from 0.5 x 10^(-4)to 2.5 x 10^(-4)for theΩ^(0)_(bc)→Λ^(+)_(c)π^(-)(E^(0)_(bc)→Λ^(+)_(c)π^(-))decay,and from 1.4x 10^(-3)to 6.9 x 10^(-3)for theΩ^(0)_(bc)→E^(+)_(c)π^(-)(E^(0)_(bc)→E^(+)_(c)π^(-))decay,depending on the considered mass and lifetime of theΩ^(0)_(bc)(E^(0)_(bc))baryon.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 mechanisms of interactions between apex and smaller carnivores may range from competition to facilitation.Conversely,interactions between predators and prey are mainly driven by the prey reducing the likelihood of...The mechanisms of interactions between apex and smaller carnivores may range from competition to facilitation.Conversely,interactions between predators and prey are mainly driven by the prey reducing the likelihood of encounters with predators.In this study,we investigated(1)the spatiotemporal interactions between an apex(the snow leopard)and a meso-predator(the red fox),and(2)the temporal interactions between the snow leopard and its potential prey(Siberian ibex,argali,Asian wild ass,Tolai hare)through camera trapping in the Mongolian Great Gobi-A.The probability of occurrence for the red fox was higher in the presence of the snow leopard than in its absence.Moreover,the red fox activity pattern matched that of the snow leopard,with both species mostly active at sunset.This positive spatiotemporal interaction suggests that the presence of the snow leopard may be beneficial for the red fox in terms of scavenging opportunities.However,other explanations may also be possible.Amongst prey,the Siberian ibex and the argali were mainly active during the day,whereas the Asian wild ass and the Tolai hare were more nocturnal.These findings suggest that potential prey(especially the Siberian ibex and the argali)may shape their behavior to decrease the opportunity for encounters with the snow leopard.Our results have revealed complex interactions between apex and smaller predators andbetween apexpredatorand its potential prey.展开更多
Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and no...Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and not on computational complexity.In order to industrialize QKD,low-cost,mass-manufactured,and practical QKD setups are required.Hence,photonic and electronic integration of the sender's and receiver's respective components is currently in the spotlight.Here we present a high-speed(2.5 GHz)integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation,as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique.Our system achieves raw bit error rates,quantum bit error rates,and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components[A.Boaron et al.,Phys.Rev.Lett.121,190502(2018)].展开更多
基金funded primarily by the Everest Snow Leopard Conservation Center,a partnership initiative of Vanke Foundation and Qomolangma National Nature Reserve Administration
文摘Habitat evaluation constitutes an important and fundamental step in the management of wildlife populations and conservation policy planning. Geographic information system （GIS） and species presence data provide the means by which such evaluation can be done. Maximum Entropy （MaxEnt） is widely used in habitat suitability modeling due to its power of accuracy and additional descriptive properties To survey snow leopard populations in Qomolangma （Mt. Everest） National Nature Reserve （QNNR）, Xizang （Tibet）, China, we pooled 127 pugmarks, 415 scrape marks, and 127 non-invasive identifications of the animal along line transects and recorded 87 occurrences through camera traps from 2014-2017. We adopted the MaxEnt model to generate a map highlighting the extent of suitable snow leopard habitat in QNNR. Results showed that the accuracy of the MaxEnt model was excellent （mean AUC=0.921）. Precipitation in the driest quarter, ruggedness, elevation, maximum temperature of the warmest month, and annual mean temperature were the main environmental factors influencing habitat suitability for snow leopards, with contribution rates of 20.0%, 14.4%, 13.3%, 8.7%, and 8.2% respectively The suitable habitat area extended for 7 001.93 km^2, representing 22.72% of the whole reserve. The regions bordering Nepal were the main suitable snow leopard habitats and consisted of three separate habitat patches Our findings revealed that precipitation, temperature conditions, ruggedness, and elevations of around 4 000 m a.s.I, influenced snow leopard preferences at the landscape level in QNNR. We advocate further research and cooperation with Nepal to evaluate habitat connectivity and to explore possible proxies of population isolation among these patches. Furthermore, evaluation of subdivisions within the protection zones of QNNR is necessary to improve conservation strategies and enhance protection.
基金This work was carried out within the framework of the EUROfusion Consortium,funded by the European Union via the Euratom Research and Training Programme(Grant Agreement No.101052200–EUROfusion)The views and opinions expressed are however those of the author(s)only and do not necessarily reflect those of the European Union or the European Commission.Neither the European Union nor the European Commission can be held responsible for them.The involved teams have operated within the framework of the Enabling Research Project:ENR-IFE.01.CEA‘Advancing shock ignition for direct-drive inertial fusion’This work was also done with the support and under the auspices of the NIFS Collaboration Research program(2021NIFS18KUGK123).
文摘Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion.The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately 3×10^(15)W/cm^(2).Experimental data suggest that high-energy electrons,with temperatures of 20–50 keV and conversion efficiencies ofη<1%,were mainly produced by the damping of electron plasma waves driven by two-plasmon decay(TPD).Stimulated Raman scattering(SRS)is observed in a near-threshold growth regime,producing a reflectivity of approximately 0.01%,and is well described by an analytical model accounting for the convective growth in independent speckles.The experiment reveals that both TPD and SRS are collectively driven by multiple beams,resulting in a more vigorous growth than that driven by single-beam laser intensity.
基金The project support from CERN and from the national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)MOST and NSFC(China)+18 种基金CNRS/IN2P3(France)BMBF,DFG and MPG(Germany)INFN(Italy)NWO(Netherlands)MNiSW and NCN(Poland)MEN/IFA(Romania)MICINN(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NP and NSF(USA).We acknowledge the computing resources that are provided by CERN,IN2P3(France),KIT and DESY(Germany),INFN(Italy),SURF(Netherlands),PIC(Spain),GridPP(United Kingdom),CSCS(Switzerland),IFIN-HH(Romania),CBPF(Brazil),Polish WLCG(Poland)and NERSC(USA).Individual groups or members have received support from ARC and ARDC(Australia)Minciencias(Colombia)AvH Foundation(Germany)EPLANET,Marie Sklodowska-Curie Actions and ERC(European Union)A*MIDEX,ANR,IPhU and Labex P2IO,and Région Auvergne-RhôneAlpes(France)Key Research Program of Frontier Sciences of CAS,CAS PIFI,CAS CCEPP,Fundamental Research Funds for the Central Universities,and Sci.&Tech.Program of Guangzhou(China)GVA,XuntaGal,GENCAT and Prog.Atracción Talento,CM(Spain)SRC(Sweden)the Leverhulme Trust,the Royal Society and UKRI(United Kingdom).
文摘A first search for the Ξ_(bc)^(+)J/ψΞ_(c)^(+) decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the Ξ+bc baryon production cross-section times the branching fraction relative to that of the B+c→J/ψD+s decay at centre-of-mass energies of 8 and 13 TeV, in the Ξ+bc and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV/c, respectively. Upper limits are presented as a function of the Ξ+bc mass and lifetime.
文摘A search for the rare decays W^(+)→D_(s)^(+)γ and Z→D0γis performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV,corresponding to an integrated luminosity of 2.0fb−1.No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W^(+)→D_(s)^(+)γ and Z→μ+μ−decays as normalization channels.The upper limits are 6.5×10^(−4) and 2.1×10^(−3) at 95% confidence level for the W^(+)→D_(s)^(+)γ and Z→D^(0)γ decay modes,respectively.This is the first reported search for the Z→D^(0)γ decay,while the upper limit on the W+→D+sγbranching fraction improves upon the previous best limit.
基金supported by the“Second National Survey of Terrestrial Wildlife Project”(grant number:20080131)funded by National Forestry and Grassland Administration of China.
文摘Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019.A total of 22 unique genotypes were identified from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis,including 13 males and 9 females.Based on the size of fecal boli,1 animal was a juvenile,9 were subadults,and 12 were adults,indicating that recruitment was limited.The effective population size was small(15.3)but there was no signature of a recent population bottleneck.We observed a low genetic diversity(He=0.46±0.05)and a high level of inbreeding(Fis of 0.43±0.11),suggesting low population viability and high risk of extinction.In total,these elephants lost nearly two thirds(62%)of their habitat in 3 decades.The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population.We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km2 of suitable habitat available.This could allow a population increase of 14 elephants,possibly by translocating individuals from elsewhere in China.Ourfindings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.
文摘Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity.A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide.Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition,the physics of fusion materials and advanced technologies for high-repetitionrate,high-average-power broadband lasers.We believe that the participation of the broader scientific community and the increased engagement of industry,in partnership with research and academic institutions,make most timely the construction of this infrastructure of extreme scientific attractiveness.
文摘First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect.Its mass and width are determined to be 4458:8±2:9t4:7-1:1 MeV and 17:3±6:5t8:0-5:7 MeV,respectively,where the quoted uncertainties are statistical and systematic.The structure is also consistent with being due to two resonances.In addition,the narrow excited■^(-)states,N■(1690)and■(1820),are seen for the first time in a■b^(-)decay,and their masses and widths are measured with improved precision.The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb^(-1),collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV.
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.
文摘Inflammatory bowel diseases(IBDs), particularly Crohn's disease(CD) and ulcerative colitis(UC), are associated with a variety of extra-intestinal manifestations(EIMs).About 36% of IBD patients have at least one EIM, which most frequently affect the joints, skin, eyes and the biliary tract.The EIMs associated with IBD have a negative impact on patients with UC and CD, and the resolution of most of them parallels that of the active IBD in terms of timing and required therapy;however, the clinical course of EIMs such as axial arthritis, pyoderma gangrenosum, uveitis, and primary sclerosing cholangitis is independent of IBD activity.The peripheral and axial arthritis associated with IBD have traditionally been treated with simple analgesics, non-steroidal anti-inflammatory drugs, steroids, sulfasalazine, methotrexate, local steroid injections and physiotherapy, but the introduction of biological response modifi ers such as tumor necrosis factor-α blockers, has led to further improvements.
基金This material is based upon work supported by the Department of Energy,National Nuclear Security Administration under Award Nos.DE-NA0001857,DE-NA0002949,and DENA0002905.The work was also supported in part by NLUF(DE-NA0002035).H.S.was supported by a DOE NNSA SSGF Fellowship(DE-FC52-08NA28752)during this work.S.A.acknowledges Sapienza Project 2016 No.RM11615502006B04,as well as EUROfusion Project Nos.AWP17-ENR-IFE-CEA-01 and ENR-IFE19.CEA-01.A.L.acknowledges the LANL LDRD program.
文摘The impact of fuel-ion diffusion in inertial confinement fusion implosions is assessed using nuclear reaction yield ratios and reaction histories.In T3He-gas-filled(with trace D)shock-driven implosions,the observed TT/T3He yield ratio is∼23lower than expected from temperature scaling.InD3He-gas-filled(with trace T)shock-driven implosions,the timing of theD3He reaction history is∼50 ps earlier than those of the DT reaction histories,and average-ion hydrodynamic simulations cannot reconcile this timing difference.Both experimental observations are consistent with reduced T ions in the burn region as predicted by multi-ion diffusion theory and particle-in-cell simulations.
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure activity within the EC’s seventh Framework Program(Application No.18110033)carried out within the framework of the EUROfusion Enabling research projects AWP19-20-ENR-IFE19.CEA01 and AWP21-ENR-01-CEA-02+2 种基金funding from the Euratom research and training programme 20192020 and 2021-2025 under grant No.633053financial support from the CNR-funded Italian research Network ELI-Italy(D.M.No.63108.08.2016)the Czech Ministry of Education,Youth and Sports,project LTT17015。
文摘We report results and modelling of an experiment performed at the Target Area West Vulcan laser facility,aimed at investigating laser±plasma interaction in conditions that are of interest for the shock ignition scheme in inertial confinement fusion(ICF),that is,laser intensity higher than 10^(16) W/cm^(2) impinging on a hot(T>1 keV),inhomogeneous and long scalelength pre-formed plasma.Measurements show a significant stimulated Raman scattering(SRS)backscattering(;%-20%of laser energy)driven at low plasma densities and no signatures of two-plasmon decay(TPD)/SRS driven at the quarter critical density region.Results are satisfactorily reproduced by an analytical model accounting for the convective SRS growth in independent laser speckles,in conditions where the reflectivity is dominated by the contribution from the most intense speckles,where SRS becomes saturated.Analytical and kinetic simulations well reproduce the onset of SRS at low plasma densities in a regime strongly affected by non-linear Landau damping and by filamentation of the most intense laser speckles.The absence of TPD/SRS at higher densities is explained by pump depletion and plasma smoothing driven by filamentation.The prevalence of laser coupling in the low-density profile justifies the low temperature measured for hot electrons(7-12 keV),which is well reproduced by numerical simulations.
基金Supported by CERNnational agencies:CAPES+30 种基金CNPqFAPERJFINEP(Brazil)MOSTNSFC(China)CNRS/IN2P3(France)BMBFDFGMPG(Germany)INFN(Italy)NWO(Netherlands)MNiSWNCN(Poland)MEN/IFA(Romania)MSHE(Russia)MinECo(Spain)SNSFSER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NPNSF(USA)Key Research Program of Frontier Sciences of CAS,CAS PIFIthe Thousand Talents Program(China)RFBRRSFYandex LLC(Russia)GVAXuntaGalGENCAT(Spain)the Royal Society and the Leverhulme Trust(United Kingdom)
文摘The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.
基金support from AvH Foundation(Germany)EPLANET,Marie Sk lodowska-Curie Actions and ERC(European Union)+11 种基金A*MIDEXANRLabex P2IOOCEVURégion Auvergne-Rh?ne-Alpes(France)Key Research Program of Frontier Sciences of CASCAS PIFIThousand Talents ProgramSci.&Tech.Program of Guangzhou(China)RFBR,RSF and Yandex LLC(Russia)GVA,Xunta Gal and GENCAT(Spain)the Royal Society and the Leverhulme Trust(United Kingdom)。
文摘A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No significant signal of the decay is observed and an upper limitof 1.1x 10^(-7)at 90%confidence level is set on the branching fraction.
基金CAPES,CNPq,FAPERJ and FINEP(Brazil)MOST and NSFC(China)+18 种基金CNRS/IN2P3(France)BMBF,DFG,MPG(Germany)INFN(Italy)NWO(Netherlands)MNiSW,NCN(Poland)MEN/IFA(Romania)MSHE(Russia)MICINN(Spain)SNSF,SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NP,NSF(USA).We acknowledge the computing resources that are provided by CERN,IN2P3(France),KIT and DESY(Germany),INFN(Italy),SURF(Netherlands),PIC(Spain),GridPP(United Kingdom),RRCKI and Yandex LLC(Russia),CSCS(Switzerland),IFIN-HH(Romania),CBPF(Brazil),PL-GRID(Poland)and NERSC(USA)AvH Foundation(Germany)EPLANET,Marie Sklodowska-Curie Actions and ERC(European Union)A*MIDEX,ANR,Labex P2IO and OCEVU,Region Auvergne-Rhdne-Alpes(France)Key Research Program of Frontier Sciences of CAS,CAS PIFI,CAS CCEPP,Fundamental Research Funds for the Central Universities,and Sci.Tech.Program of Guangzhou(China)RFBR,RSF and Yandex LLC(Russia)GVA,XuntaGal,GENCAT(Spain)the Leverhulme Trust,the Royal Society and UKRI(United Kingdom)。
文摘The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb^(-1).The baryons are reconstructed via their decays to Λ^(+)_(c)π^(-)and E^(+)_(c)π^(-).No significant excess is fbund for invariant masses between 6700 and 7300 MeV/c^(2),in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c.Upper limits are set on the ratio of the Ω^(0)_(bc)and E^(0)_(bc)production cross-section times the branching fraction to Λ^(+)_(c)π^(-)(E^(+)_(c)π^(-))relative to that of the Λ^(0)_(b)(E^(0)_(b))baryon,for different lifetime hypotheses,at 95%confidence level.The upper limits range from 0.5 x 10^(-4)to 2.5 x 10^(-4)for theΩ^(0)_(bc)→Λ^(+)_(c)π^(-)(E^(0)_(bc)→Λ^(+)_(c)π^(-))decay,and from 1.4x 10^(-3)to 6.9 x 10^(-3)for theΩ^(0)_(bc)→E^(+)_(c)π^(-)(E^(0)_(bc)→E^(+)_(c)π^(-))decay,depending on the considered mass and lifetime of theΩ^(0)_(bc)(E^(0)_(bc))baryon.
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.
基金Wildlife Initiative NGO(Mongolia)and Bavarian Association for Bird Protection(LBV-Germany)and IGA-20223107 provided the funding to realize this research.
文摘The mechanisms of interactions between apex and smaller carnivores may range from competition to facilitation.Conversely,interactions between predators and prey are mainly driven by the prey reducing the likelihood of encounters with predators.In this study,we investigated(1)the spatiotemporal interactions between an apex(the snow leopard)and a meso-predator(the red fox),and(2)the temporal interactions between the snow leopard and its potential prey(Siberian ibex,argali,Asian wild ass,Tolai hare)through camera trapping in the Mongolian Great Gobi-A.The probability of occurrence for the red fox was higher in the presence of the snow leopard than in its absence.Moreover,the red fox activity pattern matched that of the snow leopard,with both species mostly active at sunset.This positive spatiotemporal interaction suggests that the presence of the snow leopard may be beneficial for the red fox in terms of scavenging opportunities.However,other explanations may also be possible.Amongst prey,the Siberian ibex and the argali were mainly active during the day,whereas the Asian wild ass and the Tolai hare were more nocturnal.These findings suggest that potential prey(especially the Siberian ibex and the argali)may shape their behavior to decrease the opportunity for encounters with the snow leopard.Our results have revealed complex interactions between apex and smaller predators andbetween apexpredatorand its potential prey.
基金Eurostars Projects(E!11493)European Quantum Flagship project openQKD(857156)+1 种基金Italian Ministry for University and Research(PRIN2017-SRNBRK,PNRR-NQSTI)European Research Council(742745)。
文摘Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and not on computational complexity.In order to industrialize QKD,low-cost,mass-manufactured,and practical QKD setups are required.Hence,photonic and electronic integration of the sender's and receiver's respective components is currently in the spotlight.Here we present a high-speed(2.5 GHz)integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation,as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique.Our system achieves raw bit error rates,quantum bit error rates,and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components[A.Boaron et al.,Phys.Rev.Lett.121,190502(2018)].
