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Perspectives from worldwide experts on how major cities across the globe are responding to the major environmental threats of our time, including global climate change Over half of the world's population now lives in cities, and this share is expected to increase in the coming decades. With growing urbanization, cities and their residents face substantial environmental challenges such as higher temperatures, droughts, wildfires, and increased flooding. In response to these pressing challenges, some cities have begun to develop local environmental regulations that supplement national and environmental laws. In so doing, cities have stepped into a role that has been historically dominated by higher levels of government.Global Sustainable Cities takes stock of the policies that have been implemented by cities around the world in recent years in several key areas: water, air pollution, greenhouse gas emissions, and climate adaptation. It examines the advantages—and potential drawbacks—of allowing cities to assume a significant role in environmental regulation, given the legal and political constraints in which cities operate.The contributors present a series of case studies of the actions that seven leading cities—Abu Dhabi, Beijing, Berlin, Delhi, London, New York, and Shanghai—are taking to improve their environments and adapt to climate change. The first volume of its kind, Global Sustainable Cities is a critical comparative assessment of the actions that major cities in the global North and South are taking to advance sustainability

Mercury pollution and contamination are widespread, well documented, and continue to pose a public health concern in both developed and developing countries. In response to a growing need for understanding the cycling of this ubiquitous pollutant, the science of mercury has grown rapidly to include the fields of biogeochemistry, economics, sociology, public health, decision sciences, physics, global change, and mathematics. Only recently have scientists begun to establish a holistic approach to studying mercury pollution that integrates chemistry, biology, and human health sciences. Mercury in the Environment follows the process of mercury cycling through the atmosphere, through terrestrial and aquatic food webs, and through human populations to develop a comprehensive perspective on this important environmental problem. This timely reference also provides recommendations on mercury remediation, risk communication, education, and monitoring

Support for this work was provided by the NASA Solar System Observations program (80NSSC20K0673), the Space Telescope Science Institute (HST-GO-15372), the National Science Foundation (PHY-2010970), the National Research Foundation (NRF; No. 2019R1I1A1A01059609), the MINEDUC-UA project ESR1795, the European Union H2020-MSCA-ITN-2019 under Grant no. 860470 (CHAMELEON), and by the Novo Nordisk Foundation Interdisciplinary Synergy Program (NNF19OC0057374). ; Cometary activity is a manifestation of sublimation-driven processes atthe surface of nuclei. However, cometary outbursts may arise from other processes that are not necessarily driven by volatiles. In order to fully understand nuclear surfaces and their evolution, we must identify the causes of cometary outbursts. In that context, we present a study of mini-outbursts of comet 46P/Wirtanen. Six events are found in our long-term lightcurve of the comet around its perihelion passage in 2018. The apparent strengths range from -0.2 to -1.6 mag in a 5" radius aperture, and correspond to dust masses between ∼104 to 106 kg, but with large uncertainties due to the unknown grain size distributions. However, the nominal mass estimates are the same order of magnitude as the mini-outbursts at comet 9P/Tempel 1 and 67P/Churyumov-Gerasimenko, events which were notably lacking at comet 103P/Hartley 2. We compare the frequency of outbursts at the four comets, and suggest that the surface of 46P has large-scale (∼10-100 m) roughness that is intermediate to that of 67P and 103P, if not similar to the latter. The strength of the outbursts appear to be correlated with time since the last event, but a physical interpretation with respect to solar insolation is lacking. We also examine Hubble Space Telescope images taken about 2 days following a near-perihelion outburst. No evidence for macroscopic ejecta was found in the image, with a limiting radius of about 2 m. ; Publisher PDF ; Peer reviewed

LIGO and Virgo's third observing run revealed the first neutron star–black hole (NSBH) merger candidates in gravitational waves. These events are predicted to synthesize r-process elements creating optical/near-infrared 'kilonova' emission. The joint gravitational wave and electromagnetic detection of an NSBH merger could be used to constrain the equation of state of dense nuclear matter, and independently measure the local expansion rate of the Universe. Here, we present the optical follow-up and analysis of two of the only three high-significance NSBH merger candidates detected to date, S200105ae and S200115j, with the Zwicky Transient Facility. The Zwicky Transient Facility observed ~48% of S200105ae and ~22% of S200115j's localization probabilities, with observations sensitive to kilonovae brighter than −17.5 mag fading at 0.5 mag d in the g- and r-bands; extensive searches and systematic follow-up of candidates did not yield a viable counterpart. We present state-of-the-art kilonova models tailored to NSBH systems that place constraints on the ejecta properties of these NSBH mergers. We show that with observed depths of apparent magnitude ~22 mag, attainable in metre-class, wide-field-of-view survey instruments, strong constraints on ejecta mass are possible, with the potential to rule out low mass ratios, high black hole spins and large neutron star radii. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. ; This work was supported by the GROWTH (Global Relay of Observatories Watching Transients Happen) project funded by the National Science Foundation under PIRE grant no. 1545949. GROWTH is a collaborative project among California Institute of Technology (USA), University of Maryland College Park (USA), University of Wisconsin Milwaukee (USA), Texas Tech University (USA), San Diego State University (USA), University of Washington (USA), Los Alamos National Laboratory (USA), Tokyo Institute of Technology (Japan), National Central University (Taiwan), Indian Institute of Astrophysics (India), Indian Institute of Technology Bombay (India), Weizmann Institute of Science (Israel), The Oskar Klein Centre at Stockholm University (Sweden), Humboldt University (Germany), Liverpool John Moores University (UK) and University of Sydney (Australia). This work was based on observations obtained with the 48-inch Samuel Oschin Telescope and the 60-inch Telescope at the Palomar Observatory as part of the ZTF project. ZTF is supported by the National Science Foundation under grant no. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington (UW), Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee and Lawrence Berkeley National Laboratories. Operations are conducted by Caltech Optical Observatories, IPAC, and UW. The work is partly based on the observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. The KPED team (M.W.C., R.G.D., D.A.D., M.F., S.R.K., E.S. and R.R.) thanks the National Science Foundation and the National Optical Astronomical Observatory for making the Kitt Peak 2.1-m telescope available. We thank the observatory staff at Kitt Peak for their efforts to assist Robo-AO KP operations. The KPED team thanks the National Science Foundation, the National Optical Astronomical Observatory, the Caltech Space Innovation Council and the Murty family for support in the building and operation of KPED. In addition, they thank the CHIMERA project for use of the Electron Multiplying CCD (EMCCD). SED Machine is based upon work supported by the National Science Foundation under grant no. 1106171 The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: Graham). M.W.C. acknowledges support from the National Science Foundation with grant no. PHY-2010970. S.A. gratefully acknowledges support from a GROWTH PIRE grant (1545949). Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. E.C.K. acknowledges support from the G.R.E.A.T. research environment and the Wenner-Gren Foundations. F.F. gratefully acknowledges support from NASA through grant 80NSSC18K0565, from the NSF through grant PHY-1806278, and from the DOE through CAREER grant DE-SC0020435. With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013 Grant agreement n° 339108). New 14C dates for cores EW9209-1JPC and V29-202 were funded by NSF OCE grants to DWO. FN, ES and AV acknowledge FCT funding support through project UID/Multi/04326/2019. ; Rapid changes in ocean circulation and climate have been observed in marine-sediment and ice cores over the last glacial period and deglaciation, highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in climate and ocean circulation are still not fully explained. One obstacle hindering progress in our understanding of the interactions between past ocean circulation and climate changes is the difficulty of accurately dating marine cores. Here, we present a set of 92 marine sediment cores from the Atlantic Ocean for which we have established age-depth models that are consistent with the Greenland GICC05 ice core chronology, and computed the associated dating uncertainties, using a new deposition modeling technique. This is the first set of consistently dated marine sediment cores enabling paleoclimate scientists to evaluate leads/lags between circulation and climate changes over vast regions of the Atlantic Ocean. Moreover, this data set is of direct use in paleoclimate modeling studies. ; Publisher PDF ; Peer reviewed

Recently, a petition was offered to the European Commission calling for an immediate ban on animal testing. Although a Europe-wide moratorium on the use of animals in science is not yet possible, there has been a push by the non-scientific community and politicians for a rapid transition to animal-free innovations. Although there are benefits for both animal welfare and researchers, advances on alternate methods have not progressed enough to be able to replace animal research in the foreseeable future. This trend has led first and foremost to a substantial increase in the administrative burden and hurdles required to make timely advances in research and treatments for human and animal diseases. The current COVID-19 pandemic clearly highlights how much we actually rely on animal research. COVID-19 affects several organs and systems, and various animal-free alternatives currently available do not even come close to this complexity. In this Essay we therefore argue that the use of animals is essential for the advancement of human and veterinary health.

We present the temperature and polarization angular power spectra of the CMB measured by the Atacama Cosmology Telescope (ACT) from 5400 deg(2) of the 2013-2016 survey, which covers >15000 deg(2) at 98 and 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related to this, show numerous checks for systematic error done before unblinding. Using the likelihood for the cosmological analysis we constrain secondary sources of anisotropy and foreground emission, and derive a "CMB-only" spectrum that extends to l = 4000. At large angular scales, foreground emission at 150 GHz is similar to 1% of TT and EE within our selected regions and consistent with that found by Planck. Using the same likelihood, we obtain the cosmological parameters for Lambda CDM for the ACT data alone with a prior on the optical depth of tau = 0.065 +/- 0.015. Lambda CDM is a good fit. The best-fit model has a reduced chi(2) of 1.07 (PTE = 0.07) with H-0 = 67.9 +/- 1.5 km/s/Mpc. We show that the lensing BB signal is consistent with Lambda CDM and limit the celestial EB polarization angle to psi(P) = 0.07 degrees +/- 0.09 degrees. We directly cross correlate ACT with Planck and observe generally good agreement but with some discrepancies in TE. All data on which this analysis is based will be publicly released. ; National Science Foundation (NSF) AST0408698 AST-0965625 AST-1440226 PHY0355328 PHY-0855887 PHY-1214379 Princeton University University of Pennsylvania Canada Foundation for Innovation CFI under the Compute Canada Government of Ontario Ontario Research Fund \ Research Excellence University of Toronto Simons Foundation National Aeronautics & Space Administration (NASA) NNX13AE56G NNX14AB58G National Institute of Standards & Technology (NIST) - USA Cornell Presidential Postdoctoral Fellowship Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) BASAL CATA AFB-170002 National Science Foundation (NSF) AST-1814971 AST1454881 AST-1513618 AST-1907657 AST-1910021 National Research Foundation - South Africa STFC Ernest Rutherford Fellowship ST/M004856/2 STFC Consolidated Grant ST/S00033X/1 Horizon 2020 ERC Starting Grant 849169 Dicke Fellowship Mishrahi and Wilkinson funds CIfAR's Gravity & the Extreme Universe Program CGIAR Dunlap Institute

The following authors were omitted from the original version of this Data Descriptor: Markus Reichstein and Nicolas Vuichard. Both contributed to the code development and N. Vuichard contributed to the processing of the ERA-Interim data downscaling. Furthermore, the contribution of the co-author Frank Tiedemann was re-evaluated relative to the colleague Corinna Rebmann, both working at the same sites, and based on this re-evaluation a substitution in the co-author list is implemented (with Rebmann replacing Tiedemann). Finally, two affiliations were listed incorrectly and are corrected here (entries 190 and 193). The author list and affiliations have been amended to address these omissions in both the HTML and PDF versions. © 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.