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Measuring the anisotropies in astrophysical and cosmological gravitational-wave backgrounds with Taiji and LISA networks

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Science China(Physics,Mechanics & Astronomy) 2024年

作者： Zhi-Chao Zhao Sai Wang Department of Applied Physics College of Science China Agricultural University theoretical Physics division Institute of High Energy Physics Chinese Academy of Sciences

We investigate the capabilities of space-based gravitational-wave detector networks, specifically Taiji and LISA, to measure the anisotropies in stochastic gravitational-wave background(SGWB), which are characterized by the angular power spectrum. We find that a detector network can improve the measurement precision of anisotropies by at most fourteen orders of magnitude,depending on the angular multipoles. By doing so, we can enhance our understanding of the physical origins of SGWB, both in astrophysical and cosmological contexts. We assess the prospects of the detector networks for measuring the parameters of angular power spectrum. We further find an inevitable effect of cosmic variance, which can be suppressed by a better angular resolution, strengthening the importance of configuring detector networks. Our findings also suggest a potential detection of the kinematic dipole due to Doppler boosting of SGWB.

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The effects of data aggregation on long-term projections of forest stands development

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Forest Ecosystems 2024年第3期11卷 381-389页

作者： Kobra Maleki Rasmus Astrup Nicolas Cattaneo Wilson Lara Henao Clara Anton-Fernandez Norwegian Institute of Bioeconomy research Division of Forestry and Forest ResourcesP.O.Box 115ÅsNO-1431Norway

Forest management planning often relies on Airborne Laser Scanning(ALS)-based Forest Management Inventories(FMIs)for sustainable and efficient *** the area-based(ABA)approach,these inventories estimate forest characteristics for grid cell areas(pixels),which are then usually summarized at the stand *** the ALS-based high-resolution Norwegian Forest Resource Maps(16 m×16 m pixel resolution)alongside with stand-level growth and yield models,this study explores the impact of three levels of pixel aggregation(standlevel,stand-level with species strata,and pixel-level)on projected stand *** results indicate significant differences in the projected outputs based on the aggregation ***,the most substantial difference in estimated volume occurred between stand-level and pixel-level aggregation,ranging from-301 to+253 m^(3)·ha^(-1)for single *** differences were,on average,higher for broadleaves than for spruce and pine dominated stands,and for mixed stands and stands with higher variability than for pure and homogenous *** conclusion,this research underscores the critical role of input data resolution in forest planning and management,emphasizing the need for improved data collection practices to ensure sustainable forest management.

关键词： Growth and yield models Dominant species Norway spruce Scots pine Broadleaves Forest resource map Stand variability

Estimating wood quality attributes from dense airborne LiDAR point clouds

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Forest Ecosystems 2024年第2期11卷 226-235页

作者： Nicolas Cattaneo Stefano Puliti Carolin Fischer Rasmus Astrup Norwegian Institute of Bioeconomy research(NIBIO) Division of Forest and Forest ResourcesHøgskoleveien 81433ÅsNorway

Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest *** present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing *** object reconstruction methods,our approach is based on simple metrics computed on vertical slices that summarize information on point distances,angles,and geometric attributes of the space between and around the *** models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser *** show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation *** approach provides a simple,clear,and scalable solution that can be adapted to different situations both for research and more operational mapping.

关键词： UAV laser scanning Wood quality Machine learning Point cloud metrics

Non-monotonic behavior of jam probability and stretchedexponential distribution in pedestrian counterflow

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Chinese Physics B 2024年第9期33卷 259-266页

作者： Ze-Hao Chen Zhi-Xi Wu Jian-Yue Guan College of Physical Science and Technology Guangxi Normal UniversityGuilin 541004China Lanzhou Center for theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory for Quantum Theory and Applications of the Ministry of EducationLanzhou UniversityLanzhou 730000China

We adopt a floor field cellular automata model to study the statistical properties of bidirectional pedestrian flow movingin a straight corridor. We introduce a game-theoretic framework to deal with the conflict of multiple pedestrians tryingto move to the same target location. By means of computer simulations, we show that the complementary cumulative distributionof the time interval between two consecutive pedestrians leaving the corridor can be fitted by a stretched exponentialdistribution, and surprisingly, the statistical properties of the two types of pedestrian flows are affected differently by theflow ratio, i.e., the ratio of the pedestrians walking toward different directions. We also find that the jam probability exhibitsa non-monotonic behavior with the flow ratio, where the worst performance arises at an intermediate flow ratio of around0.2. Our simulation results are consistent with some empirical observations, which suggest that the peculiar characteristicsof the pedestrians may attributed to the anticipation mechanism of collision avoidance.

关键词： traffic and crowd dynamics evolutionary game theory

Flow Injection Analysis Technique for Online Preconcentration of Lead Ions in Airborne Particulate Matter Using Imprinted Polymer as the Sorbent

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Journal of Analysis and Testing 2024年第2期8卷 180-190页

作者： Muhammad Bachri Amran Novita Ambarsari Muhammad Ali Zulfikar Asri Indrawati Rusnadi Rusnadi Saipul Hamdi Analytical Chemistry division Faculty of Mathematics and Natural SciencesInstitut Teknologi BandungBandung 40132Indonesia research Center for Climate and Atmosphere National Research and Innovation AgencyBandung 40135Indonesia

This work reported a simple and sensitive flow injection analysis(FIA)technique coupled with a Flame Atomic Absorption Spectrophotometer(FAAS)for online preconcentration of lead(Ⅱ)ions in the airborne particulate matter samples(PM_(2.5))using ion-imprinted polymers as adsorbent packed in minicolumn.A bulk polymerization method was chosen to synthesize the polymer based on a ternary complex of lead ions with 4-2-pyridilazo resorcinol and 4-vinyl pyridine with methacrylic acid as a functional *** optimum pH for sorption was 6,and other variables for the FIA system were optimized,including breakthrough volume,eluent concentration,and eluent *** optimum conditions were reached with a breakthrough volume of 4.45 mL,calculated as a dynamic retention capacity of 5.20 mg/g of Pb(II)40 mg/L,with a 1.5 mL/min flow *** eluent used for the FIA system was 0.5 mL HNO_(3)of 3 mol/***,precision,and limits of detection of the FIA system were determined before being applied to preconcentration and analysis of lead ions in PM_(2.5)*** precision of the method was determined to be 3.09%by calculating the coefficients of the *** of the method in the concentration range of 50-1000μg/L gave a coefficient correlation of 0.9925,showing a good response,and the limit of detection of the system was 5.11μg/L,better than that of the FAAS *** of the FIA system were evaluated and showed good results with an enrichment factor of more than 20 times higher and a concentration efficiency of 11.65 min^(-1)with a consumptive index of 4.5 *** and analysis of the PM_(2.5)samples in Bandung City showed the concentrations of Pb(II)were 26.67μg/L and 33.3μg/L with the accuracy of the method for each sample of104.75%and 107.86%.

关键词： Flow injection analysis Lead(II)ions Imprinted polymer Particulate matter

Study of Type-B QPOs Observed in Black Hole X-Ray Binary Swift J1728.9-3613

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research in Astronomy and Astrophysics 2024年第3期24卷 1-9页

作者： Raj Kumar Astrophysical Sciences division Bhabha Atomic Research CentreMumbai 400085India Homi Bhabha National Institute Mumbai 400094India

We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it disappeared as flux increased,but again appeared at∼7.70 Hz when flux was dramatically *** source was found in the soft intermediate state during these *** further studied the energy dependence of the *** found that QPO was observed only for a higher energy range implying that the origin of QPO is possibly due to the corona emitting higher energy photons by the inverse Compton *** variation of spectral parameters can be explained with the disk truncation *** fractional rms was found to be monotonically increased with *** phase lag spectrum followed the“U-shaped”*** rms and phase lag spectrum are modeled and explained with the single-component Comptonization model vkompthdk.

关键词： X-rays binaries-accretion-accretion disks-X-rays individual (Swift J1728.9-3613)

Precise determination of the pole position of the exotic Z_(c)(3900)

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 84-90页

作者： Yun-Hua Chen Meng-Lin Du Feng-Kun Guo School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Physics University of Electronic Science and Technology of ChinaChengdu 611731China CAS Key Laboratory of theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Peng Huanwu Collaborative Center for research and Education Beihang UniversityBeijing 100191China

We perform a unified description of the experimental data of the π^(+)π^(-)and J/ψπ^(±)invariant mass spectra for e^(+)e^(-)→J/ψπ^(+)π^(-)and the D^(0)D^(*-)mass spectrum for e^(+)e^(-)→D^(0)D^(*-)π^(+)at e^(+)e^(-)center-of-mass energies 4.23 and 4.26 *** analysis takes into account open-charm meson loops that contain triangle singularities,the J/ψπ-DD^(*)coupled-channel interaction respecting unitarity,and the strong ππ-KK final state interaction using dispersion *** analysis leads to a precise determination of the Z_(c)(3900)pole with the pole mass and width(3880.7±1.7_(stat)±22.4_(syst))MeV and(35.9±1.4_(stat)±15.3_(syst))MeV,respectively,and hints at that the DD^(*)molecular and non-molecular components are of similar importance in the Z_(c)(3900)formation.

关键词： exotic hadrons dispersion relations final state interaction triangle singularity

Resident immune responses to spinal cord injury:role of astrocytes and microglia

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Neural Regeneration research 2024年第8期19卷 1678-1685页

作者： Sydney Brockie Cindy Zhou Michael G.Fehlings division of Genetics and Development Krembil Research InstituteUniversity Health NetworkTorontoONCanada Institute of Medical Science University of TorontoTorontoONCanada division of Neurosurgery and Spine Program Department of SurgeryUniversity of TorontoTorontoONCanada

Spinal cord injury can be traumatic or non-traumatic in origin,with the latter rising in incidence and prevalence with the aging demographics of our *** r,as the global population ages,individuals with co-existent degenerative spinal pathology comprise a growing number of traumatic spinal cord injury cases,especially involving the cervical spinal *** makes recovery and treatment approaches particula rly challenging as age and comorbidities may limit regenerative *** these reasons,it is critical to better understand the complex milieu of spinal cord injury lesion pathobiology and the ensuing inflammatory *** review discusses microglia-specific purinergic and cytokine signaling pathways,as well as microglial modulation of synaptic stability and plasticity after ***,we evaluate the role of astrocytes in neurotransmission and calcium signaling,as well as their border-forming response to neural *** the inflammatory and reparative roles of these cells have eluded our complete understanding and remain key therapeutic targets due to their extensive structural and functional roles in the nervous *** advances have shed light on the roles of glia in neurotransmission and reparative injury responses that will change how interventions are *** key processes and existing knowledge gaps will allow future research to effectively target these cells and harness their regenerative potential.

关键词： astrocytes glial signaling microglia spinal cord injury synaptic transmission

Molecular dynamics study of primary radiation damage in TiVTa concentrated solid-solution alloy

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Chinese Physics B 2024年第3期33卷 530-535页

作者：赵永鹏豆艳坤贺新福曹晗王林枫邓辉球杨文 Reactor Engineering Technology research division China Institute of Atomic EnergyBeijing 102413China School of Physics and Electronics Hunan UniversityChangsha 410082China

The primary radiation damage in pure V and TiVTa concentrated solid-solution alloy(CSA)was studied using a molecular dynamics *** have performed displacement cascade simulations to explore the generation and evolution behavior of irradiation *** results demonstrate that the defect accumulation and agglomeration in TiVTa CSA are significantly suppressed compared to pure *** peak value of Frenkel pairs during cascade collisions in TiVTa CSA is much higher than that in pure V due to the lower formation energy of point ***,the longer lifetime of the thermal spike relaxation and slow energy dissipation capability of TiVTa CSA can facilitate the recombination of point *** defect agglomeration rate in TiVTa CSA is much lower due to the lower binding energy of interstitial clusters and reduced interstitial ***,the occurrence probability of dislocation loops in TiVTa CSA is lower than that in pure *** reduction in primary radiation damage may enhance the radiation resistance of TiVTa CSA,and the improved radiation tolerance is primarily attributed to the relaxation stage and long-term defect evolution rather than the ballistic *** results can provide fundamental insights into irradiation-induced defects evolution in refractory CSAs.

关键词： concentrated solid-solution alloy primary radiation damage molecular dynamics simulation