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Spatio-Temporal Stratified Associations between Urban Human Activities and Crime Patterns: A Case Study in San Francisco Around the Covid-19 Stay-at-Home Mandate

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SSRN 2022年

作者： Chen, Tongxin Bowers, Kate Zhu, Di Gao, Xiaowei Cheng, Tao Space Time Lab for Big Data Analytics Department of Civil Environmental and Geomatic Engineering University College London LondonWC1E 6BT United Kingdom Department of Security and Crime Science University College London LondonWC1H 9EZ United Kingdom Geospatial Data Intelligence Lab Department of Geography Environment and Society University of Minnesota Twin Cities Minneapolis55455 United States

Crime changes have been reported as a result of human routine activity shifting due to containment policies, such as stay-at-home (SAH) mandates during the COVID-19 pandemic. However, the way in which the manifestation of crime in both space and time is affected by dynamic human activities in urban areas has not been explored in depth in empirical studies hitherto. Here, we aim to quantitatively measure the spatio-temporal associations between crime patterns and human activities in the context of an unstable period of the ever-changing socio-demographic backcloth. We propose an analytical framework to detect the dynamic stratified associations between the spatial distributions of human activities and crimes. The results of a case study in San Francisco, United States reveal that the spatial patterns of most crime types are statistically significantly associated with that of human activities zones. Property crime exhibits higher stratified association than violent crime across all temporal scales. Further, the strongest association is obtained with the eight-week time span centered around the SAH order. These findings not only enhance our understanding of the relationships between urban crime and human activities, but also offer insights that tailored crime intervention strategies need to consider human activity variables. © 2022, The Authors. All rights reserved.

关键词： Crime

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A binary pulsar in a 53-minute orbit

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NATURE 2023年第7976期620卷 961-964页

作者： Pan, Z. Lu, J. G. Jiang, P. Han, J. L. Chen, H. -l. Han, Z. W. Liu, K. Qian, L. Xu, R. X. Zhang, B. Luo, J. T. Yan, Z. Yang, Z. L. Zhou, D. J. Wang, P. F. Wang, C. Li, M. H. Zhu, M. Chinese Acad Sci Natl Astron Observ Beijing Peoples R China Guizhou Univ Guizhou Radio Astron Observ Guiyang Peoples R China Chinese Acad Sci Univ Chinese Acad Sci Coll Astron & Space Sci Beijing Peoples R China Chinese Acad Sci Key Lab Radio Astron & Technol Beijing Peoples R China Chinese Acad Sci Yunnan Observ Kunming Peoples R China Chinese Acad Sci Univ Chinese Acad Sci Beijing Peoples R China Max Planck Inst Radioastron Bonn Germany Peking Univ Dept Astron Beijing Peoples R China Peking Univ Kavli Inst Astron & Astrophys Beijing Peoples R China Peking Univ Sch Phys State Key Lab Nucl Phys & Technol Beijing Peoples R China Univ Nevada Nevada Ctr Astrophys Las Vegas NV 89154 USA Univ Nevada Dept Phys & Astron Las Vegas NV 89154 USA Chinese Acad Sci Natl Time Serv Ctr Xian Peoples R China Chinese Acad Sci Shanghai Astron Observ Shanghai Peoples R China Guizhou Univ State Key Lab Publ Big Data Guiyang Peoples R China

Spider pulsars are neutron stars that have a companion star in a close orbit. The companion star sheds material to the neutron star, spinning it up to millisecond rotation periods, while the orbit shortens to hours. The companion is eventually ablated and destroyed by the pulsar wind and radiation(1,2). Spider pulsars are key for studying the evolutionary link between accreting X-ray pulsars and isolated millisecond pulsars, pulsar irradiation effects and the birth of massive neutron stars(3-6). Black widow pulsars in extremely compact orbits (as short as 62 minutes(7)) have companions with masses much smaller than 0.1 M circle dot. They may have evolved from redback pulsars with companion masses of about 0.1-0.4 M. and orbital periods of less than 1 day(8). If this is true, then there should be a population of millisecond pulsars with moderate-mass companions and very short orbital periods(9), but, hitherto, no such system was known. Here we report radio observations of the binary millisecond pulsar PSR J1953+1844 (M71E) that show it to have an orbital period of 53.3 minutes and a companion with a mass of around 0.07 M circle dot. It is a faint X-ray source and located 2.5 arcminutes from the centre of the globular cluster M71.

关键词： Compact astrophysical objects Stellar evolution

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Using CYGNSS data to Map Flood Inundation during the 2021 Extreme Precipitation in Henan Province, China

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REMOTE SENSING 2021年第24期13卷 5181-5181页

作者： Zhang, Shuangcheng Ma, Zhongmin Li, Zhenhong Zhang, Pengfei Liu, Qi Nan, Yang Zhang, Jingjiang Hu, Shengwei Feng, Yuxuan Zhao, Hebin Changan Univ Coll Geol Engn Xian 710054 Peoples R China State Key Lab Geoinformat Engn Xian 710054 Peoples R China Changan Univ Big Data Ctr Geosci & Satellites Xian 710054 Peoples R China Minist Educ Key Lab Western Chinas Mineral Resources & Geol E Xian 710054 Peoples R China Chinese Acad Sci Natl Time Serv Ctr Xian 710600 Peoples R China CSIC Inst Space Sci ICE Earth Observat Res Grp Barcelona 08290 Spain Wuhan Univ GNSS Res Ctr Wuhan 430079 Peoples R China China Meteorol Adm Inst Urban Meteorol Beijing 100089 Peoples R China

On 20 July 2021, parts of China's Henan Province received the highest precipitation levels ever recorded in the region. Floods caused by heavy rainfall resulted in hundreds of casualties and tens of billions of dollars' worth of property loss. Due to the highly dynamic nature of flood disasters, rapid and timely spatial monitoring is conducive for early disaster prevention, mid-term disaster relief, and post-disaster reconstruction. However, existing remote sensing satellites cannot provide high-resolution flood monitoring results. Seeing as spaceborne global navigation satellite system-reflectometry (GNSS-R) can observe the Earth's surface with high temporal and spatial resolutions, it is expected to provide a new solution to the problem of flood hazards. Here, using the Cyclone Global Navigation Satellite System (CYGNSS) L1 data, we first counted various signal-to-noise ratios and the corresponding reflectivity to surface features in Henan Province. Subsequently, we analyzed changes in the delay-Doppler map of CYGNSS when the observed area was submerged and not submerged. Finally, we determined the submerged area affected by extreme precipitation using the threshold detection method. The results demonstrated that the flood range retrieved by CYGNSS agreed with that retrieved by the Soil Moisture Active Passive (SMAP) mission and the precipitation data retrieved and measured by the Global Precipitation Measurement mission and meteorological stations. Compared with the SMAP results, those obtained by CYGNSS have a higher spatial resolution and can monitor changes in the areas affected by the floods over a shorter period.

关键词： Cyclone Global Navigation Satellite System flood inundation extreme precipitation global navigation satellite system-reflectometry Soil Moisture Active Passive

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The Discovery of Three Pulsars in the Globular Cluster M15 with FAST

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ASTROPHYSICAL JOURNAL LETTERS 2024年第2期974卷 L23页

作者： Wu, Yuxiao Pan, Zhichen Qian, Lei Ransom, Scott M. Eatough, Ralph P. Wang, Bojun Freire, Paulo C. C. Liu, Kuo Yan, Zhen Luo, Jintao Zhang, Liyun Li, Minghui Yin, Dejiang Li, Baoda Li, Yifeng Dai, Yinfeng Li, Yaowei Zhang, Xinnan Liu, Tong Pan, Yu Chongqing Univ Posts & Telecommun Sch Sci Chongqing 40000 Peoples R China Chinese Acad Sci Natl Astron Observ 20A Datun Rd Beijing 100101 Peoples R China Chinese Acad Sci CAS Key Lab FAST Natl Astron Observ Beijing 100101 Peoples R China Univ Chinese Acad Sci Coll Astron & Space Sci Beijing 100049 Peoples R China Natl Radio Astron Observ Charlottesville VA 22903 USA Max Planck Inst Radioastron Hugel 69 D-53121 Bonn Germany Chinese Acad Sci Shanghai Astron Observ 80 Nandan Rd Shanghai 200030 Peoples R China Chinese Acad Sci Natl Time Serv Ctr Xian 710600 Peoples R China Guizhou Univ Coll Phys Guiyang 550025 Peoples R China Guizhou Univ State Key Lab Publ Big Data Guiyang 550025 Peoples R China

We present the discovery of three pulsars in the globular cluster (GC) M15 (NGC 7078) by the Five-hundred-meter Aperture Spherical Radio Telescope. PSR J2129+1210J (M15J) is a millisecond pulsar with a spin period of 11.84 ms and a dispersion measure of 66.68 pc cm-3. Both PSR J2129+1210K and L (M15K and L) are long-period pulsars with spin periods of 1928 ms and 3961 ms, respectively. M15L is the GC pulsar with the longest spin period known. We update the timing solutions of M15A to M15H. As predicted by A. Ridolfi et al., the flux density of M15C keeps decreasing, and the latest detection in our data set was on 2022 December 20. We have also detected M15I's signal for the first time since its discovery. Current timing suggests that it is an isolated pulsar.

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A change in the optical polarization associated with a γ-ray flare in the blazar 3C 279

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NATURE 2010年第7283期463卷 919-923页

作者： Abdo, A. A. Ackermann, M. Ajello, M. Axelsson, M. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Baughman, B. M. Bechtol, K. Bellazzini, R. Berenji, B. Blandford, R. D. Bloom, E. D. Bock, D. C. -J. Bogart, J. R. Bonamente, E. Borgland, A. W. Bouvier, A. Bregeon, J. Brez, A. Brigida, M. Bruel, P. Burnett, T. H. Buson, S. Caliandro, G. A. Cameron, R. A. Caraveo, P. A. Casandjian, J. M. Cavazzuti, E. Cecchi, C. Celik, Oe Chekhtman, A. Cheung, C. C. Chiang, J. Ciprini, S. Claus, R. Cohen-Tanugi, J. Collmar, W. Cominsky, L. R. Conrad, J. Corbel, S. Corbet, R. Costamante, L. Cutini, S. Dermer, C. D. de Angelis, A. de Palma, F. Digel, S. W. do Couto e Silva, E. Drell, P. S. Dubois, R. Dumora, D. Farnier, C. Favuzzi, C. Fegan, S. J. Ferrara, E. C. Focke, W. B. Fortin, P. Frailis, M. Fuhrmann, L. Fukazawa, Y. Funk, S. Fusco, P. Gargano, F. Gasparrini, D. Gehrels, N. Germani, S. Giebels, B. Giglietto, N. Giommi, P. Giordano, F. Giroletti, M. Glanzman, T. Godfrey, G. Grenier, I. A. Grove, J. E. Guillemot, L. Guiriec, S. Hanabata, Y. Harding, A. K. Hayashida, M. Hays, E. Horan, D. Hughes, R. E. Iafrate, G. Itoh, R. Jackson, M. S. Johannesson, G. Johnson, A. S. Johnson, W. N. Kadler, M. Kamae, T. Katagiri, H. Kataoka, J. Kawai, N. Kerr, M. Knoedlseder, J. Kocian, M. L. Kuss, M. Lande, J. Larsson, S. Latronico, L. Lemoine-Goumard, M. Longo, F. Loparco, F. Lott, B. Lovellette, M. N. Lubrano, P. Macquart, J. Madejski, G. M. Makeev, A. Max-Moerbeck, W. Mazziotta, M. N. McConville, W. McEnery, J. E. McGlynn, S. Meurer, C. Michelson, F. Mitthumsiri, W. Mizuno, T. Moiseev, A. A. Monte, C. Monzani, M. E. Morselli, A. Moskalenko, I. V. Murgia, S. Nestoras, I. Nolan, P. L. Norris, J. P. Nuss, E. Ohsugi, T. Okumura, A. Omodei, N. Orlando, E. Ormes, J. F. Paneque, D. Panetta, J. H. Parent, D. Pavlidou, V. Pearson, T. J. Pelassa, V. Pepe, M. Pesce-Rollins, M. Piron, F. Porter, T. A. Raino, S. Rando, R. Razzano, M. Readhead, A. Reimer, A. Reimer, O. Reposeur, T. Reyes, L. C. Richards, J. L. Rochester, L. S. Rodriguez, A. Y. Roth, M. R Stanford Univ Dept Phys WW Hansen Expt Phys Lab Kavli Inst Particle Astrophys & Cosmol Stanford CA 94305 USA USN Res Lab Div Space Sci Washington DC 20375 USA Natl Acad Sci Natl Res Council Res Associate Washington DC 20001 USA Stanford Univ SLAC Natl Accelerator Lab Stanford CA 94305 USA Stockholm Univ Dept Astron SE-10691 Stockholm Sweden AlbaNova Oskar Klein Ctr Cosmoparticle Phys SE-10691 Stockholm Sweden Ist Nazl Fis Nucl Sez Pisa I-56127 Pisa Italy Univ Paris Diderot CEA Saclay CNRS IRFULab AIMServ Astrophys F-91191 Gif Sur Yvette France Ist Nazl Fis Nucl Sez Trieste I-34127 Trieste Italy Univ Trieste Dipartmento Fis I-34127 Trieste Italy Ist Nazl Fis Nucl Sez Padova I-35131 Padua Italy Univ Padua Dipartimento Fis Galileo Galilei I-35131 Padua Italy Ohio State Univ Dept Phys Ctr Cosmol & Astroparticle Phys Columbus OH 43210 USA CARMA Big Pine CA 93514 USA Univ Calif Berkeley Radio Astron Lab Berkeley CA 94720 USA Ist Nazl Fis Nucl Sez Perugia I-06123 Perugia Italy Univ Perugia Dipartimento Fis I-06123 Perugia Italy Univ Politecn Bari Dipartimento Fis M Merlin I-70126 Bari Italy Ist Nazl Fis Nucl Sez Bari I-70126 Bari Italy Ecole Polytech CNRS IN2P3 Lab Leprince Ringuet F-91128 Palaiseau France Univ Washington Dept Phys Seattle WA 98195 USA CSIC IEEC Inst Ciencies Espai Barcelona 08193 Spain Ist Astrofis Spaziale & Fis Cosm INAF I-20133 Milan Italy Sci Data Ctr ASI I-00044 Frascati Roma Italy NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA NASA CRESST Greenbelt MD 20771 USA Univ Maryland Baltimore Cty Dept Phys Baltimore MD 21250 USA Univ Maryland Baltimore Cty Ctr Space Sci & Technol Baltimore MD 21250 USA George Mason Univ Fairfax VA 22030 USA Univ Montpellier 2 CNRS IN2P3 Lab Phys Theor & Astroparticules F-34095 Montpellier France Max Planck Inst Extraterr Phys D-85748 Garching Germany Sonoma State Univ Dept Phys & Astron Rohnert Pk CA 94928 USA Stockholm Univ Dept Phys SE-10691 Stockholm Swe

It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight(1). The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma (gamma)-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and gamma-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10(5) gravitational radii.

关键词： Astrophysics Infrared radiation space telescopes Accretion disks

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γ-RAY AND PARSEC-SCALE JET PROPERTIES OF A COMPLETE SAMPLE OF BLAZARS FROM THE MOJAVE PROGRAM

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ASTROPHYSICAL JOURNAL 2011年第1期742卷 27-27页

作者： Lister, M. L. Aller, M. Aller, H. Hovatta, T. Kellermann, K. I. Kovalev, Y. Y. Meyer, E. T. Pushkarev, A. B. Ros, E. Ackermann, M. Antolini, E. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Bechtol, K. Bellazzini, R. Berenji, B. Blandford, R. D. Bloom, E. D. Boeck, M. Bonamente, E. Borgland, A. W. Bregeon, J. Brigida, M. Bruel, P. Buehler, R. Buson, S. Caliandro, G. A. Cameron, R. A. Caraveo, P. A. Casandjian, J. M. Cavazzuti, E. Cecchi, C. Chang, C. S. Charles, E. Chekhtman, A. Cheung, C. C. Chiang, J. Ciprini, S. Claus, R. Cohen-Tanugi, J. Conrad, J. Cutini, S. de Palma, F. Dermer, C. D. do Couto e Silva, E. Drell, P. S. Drlica-Wagner, A. Favuzzi, C. Fegan, S. J. Ferrara, E. C. Finke, J. Focke, W. B. Fortin, P. Fukazawa, Y. Fusco, P. Gargano, F. Gasparrini, D. Gehrels, N. Germani, S. Giglietto, N. Giordano, F. Giroletti, M. Glanzman, T. Godfrey, G. Grenier, I. A. Guiriec, S. Hadasch, D. Hayashida, M. Hays, E. Horan, D. Hughes, R. E. Johannesson, G. Johnson, A. S. Kadler, M. Katagiri, H. Kataoka, J. Knoedlseder, J. Kuss, M. Lande, J. Longo, F. Loparco, F. Lott, B. Lovellette, M. N. Lubrano, P. Madejski, G. M. Mazziotta, M. N. McConville, W. McEnery, J. E. Mehault, J. Michelson, P. F. Mizuno, T. Monte, C. Monzani, M. E. Morselli, A. Moskalenko, I. V. Murgia, S. Naumann-Godo, M. Nishino, S. Nolan, P. L. Norris, J. P. Nuss, E. Ohno, M. Ohsugi, T. Okumura, A. Omodei, N. Orlando, E. Ozaki, M. Paneque, D. Parent, D. Pesce-Rollins, M. Pierbattista, M. Piron, F. Pivato, G. Raino, S. Readhead, A. Reimer, A. Reimer, O. Richards, J. L. Ritz, S. Sadrozinski, H. F-W Sgro, C. Shaw, M. S. Siskind, E. J. Spandre, G. Spinelli, P. Takahashi, H. Tanaka, T. Thayer, J. G. Thayer, J. B. Thompson, D. J. Tosti, G. Tramacere, A. Troja, E. Usher, T. L. Vandenbroucke, J. Vasileiou, V. Vianello, G. Vitale, V. Waite, A. P. Wang, P. Winer, B. L. Wood, K. S. Zimmer, S. Purdue Univ Dept Phys W Lafayette IN 47907 USA Univ Michigan Dept Astron Ann Arbor MI 48109 USA Owens Valley Radio Observ Big Pine CA 93513 USA Natl Radio Astron Observ Charlottesville VA 22903 USA PN Lebedev Phys Inst Ctr Astro Space Moscow 117997 Russia Max Planck Inst Radioastron D-53121 Bonn Germany Rice Univ Dept Phys & Astron Houston TX 77005 USA Pulkovo Observ St Petersburg 196140 Russia Crimean Astrophys Observ UA-98409 Nauchnyi Crimea Ukraine Univ Valencia Dept Astron & Astrofis E-46100 Valencia Spain Stanford Univ WW Hansen Expt Phys Lab Kavli Inst Particle Astrophys & Cosmol Dept Phys Stanford CA 94305 USA Stanford Univ SLAC Natl Accelerator Lab Stanford CA 94305 USA Ist Nazl Fis Nucl Sez Perugia I-06123 Perugia Italy Univ Perugia Dipartimento Fis I-06123 Perugia Italy Ist Nazl Fis Nucl Sez Pisa I-56127 Pisa Italy Univ Paris Diderot Lab AIM CEA IRFU CNRSServ AstrophysCEA Saclay F-91191 Gif Sur Yvette France Ist Nazl Fis Nucl Sez Trieste I-34127 Trieste Italy Univ Trieste Dipartimento Fis I-34127 Trieste Italy Ist Nazl Fis Nucl Sez Padova I-35131 Padua Italy Univ Padua Dipartimento Fis G Galilei I-35131 Padua Italy Dr Remeis Sternwarte Bamberg D-96049 Bamberg Germany ECAP D-96049 Bamberg Germany Univ Politecn Bari Dipartimento Fis M Merlin I-70126 Bari Italy Ist Nazl Fis Nucl Sez Bari I-70126 Bari Italy Ecole Polytech CNRS Lab Leprince Ringuet IN2P3 F-91128 Palaiseau France Inst Ciencies Espai IEEE CSIC Barcelona 08193 Spain INAF Ist Astrofis Spaziale & Fis Cosm I-20133 Milan Italy Inst Radioastron Millimetr F-38406 St Martin Dheres France Artep Inc Ellicott City MD 21042 USA Natl Acad Sci Natl Res Council Washington DC 20001 USA ASI Sci Data Ctr I-00044 Rome Italy Univ Montpellier 2 Lab Univers & Particules Montpellier CNRS IN2P3 Montpellier France Stockholm Univ Dept Phys SE-10691 Stockholm Sweden Oskar Klein Ctr Cosmoparticle Phys SE-10691 Stockholm Sweden USN Div Space Sci Res Lab Washington DC 20

We investigate the Fermi Large Area Telescope gamma-ray and 15 GHz Very Long Baseline Array radio properties of a joint gamma-ay and radio-selected sample of active galactic nuclei (AGNs) obtained during the first 11 months of the Fermi mission (2008 August 4-2009 July 5). Our sample contains the brightest 173 AGNs in these bands above declination -30 degrees during this period, and thus probes the full range of gamma-ray loudness (gamma-ray to radio band luminosity ratio) in the bright blazar population. The latter quantity spans at least 4 orders of magnitude, reflecting a wide range of spectral energy distribution (SED) parameters in the bright blazar population. The BL Lac objects, however, display a linear correlation of increasing gamma-ray loudness with synchrotron SED peak frequency, suggesting a universal SED shape for objects of this class. The synchrotron self-Compton model is favored for the gamma-ray emission in these BL Lac objects over external seed photon models, since the latter predict a dependence of Compton dominance on Doppler factor that would destroy any observed synchrotron SED-peak-gamma-ray-loudness correlation. The high-synchrotron peaked (HSP) BL Lac objects are distinguished by lower than average radio core brightness temperatures, and none display large radio modulation indices or high linear core polarization levels. No equivalent trends are seen for the flat-spectrum radio quasars (FSRQs) in our sample. Given the association of such properties with relativistic beaming, we suggest that the HSP BL Lac objects have generally lower Doppler factors than the lower-synchrotron peaked BL Lac objects or FSRQs in our sample.

关键词： BL Lacertae objects: general galaxies: active galaxies: jets gamma rays: galaxies quasars: general radio continuum: galaxies

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