bluuebunny/crossref_metadata_2025_split huggingface dataset:
Saving ourselves? On rescue and humanitarian action
Authors: Radice Henry 
Published: January 2019

AbstractThis article contributes to the international political theory of humanitarianism by unpicking the politics of humanitarian action’s simplest expression: saving human lives in the name of humanity. Both saving lives and defining notions of common humanity are closely interrelated acts of power. What saving a life means depends on a prior definition of humanity; humanitarians’ acts of rescue are the measure of their commitment to humanity. The politics of rescue and the politics of humanity are inextricably linked. The article explores four facets of this nexus. First, it considers the meanings of rescue, from saving bodies to saving lives, linked to contingent understandings of humanity. Second, it turns to the rescuers, for whom rescue performs particular functions, not least the need to preserve a sense of self. Third, it situates their often narcissistic motives in relation to the consequences of humanitarian action. Fourth, it addresses the power imbalance inherent in rescue and the problem of causing harm. It concludes that rescue is always an act of presumption, but one that can be tempered by humanitarian actors willing to embrace their role as ‘moral politicians’ (Walzer), aware of their power and their dirty hands, and open to contrasting understandings of humanity.
Effects of Anodal Transcranial Direct Current Stimulation (atDCS) on Sentence Comprehension
Authors: Lum Jarrad A. G. , Clark Gillian M. , Rogers Caitlyn M. , Skalkos James D. , Fuelscher Ian , Hyde Christian , Enticott Peter G. 
Published: January 2019

AbstractObjectives: This study examined the effects of anodal transcranial direct current stimulation (a-tDCS) on sentence and word comprehension in healthy adults. Methods: Healthy adult participants, aged between 19 and 30 years, received either a-tDCS over the left inferior frontal gyrus (n=18) or sham stimulation (n=18). Participants completed sentence comprehension and word comprehension tasks before and during stimulation. Accuracy and reaction times (RTs) were recorded as participants completed both tasks. Results: a-tDCS was found to significantly decrease RT on the sentence comprehension task compared to baseline. There was no change in RT following sham stimulation. a-tDCS was not found to have a significant effect on accuracy. Also, a-tDCS did not affect accuracy or RTs on the word comprehension task. Conclusions: The study provides evidence that non-invasive anodal electrical stimulation can modulate sentence comprehension in healthy adults, at least compared to their baseline performance. (JINS, 2019, 25, 331–335)
Navigating complex financial decisions at retirement: evidence from annuity choices in public sector pensions
Authors: Clark Robert L. , Hammond Robert G. , Vanderweide David 
Published: January 2019

AbstractChoices regarding the disposition of wealth at retirement can have substantial implications for retirement income security. We analyze the factors determining annuity payout option choices within the context of a public sector defined pension plan with no default annuity option. Using combined administrative records and survey data, we explore the role of individual and household characteristics as well as risk preferences, time preferences, and financial literacy. We also document retiree well-being and satisfaction with retirement decision making. The evidence is consistent with predictions over which households might benefit most from each annuity option. Comparing retirees who chose different types of annuities, we find that these groups of retirees report very different levels of well-being in retirement. All retirees report lower levels of retirement income security over time, with strong differences among those who chose different types of annuities.
Merging massive black holes the right place and the right time
Authors: Lamberts Astrid 
Published: January 2019

AbstractThe LIGO/Virgo detections of gravitational waves from merging black holes of ≃ 30 solar mass suggest progenitor stars of low metallicity (Z/Z⊙≲ 0.3). In this talk I will provide constrains on where the progenitors of GW150914 and GW170104 may have formed, based on advanced models of galaxy formation and evolution combined with binary population synthesis models. First I will combine estimates of galaxy properties (star-forming gas metallicity, star formation rate and merger rate) across cosmic time to predict the low redshift BBH merger rate as a function of present day host galaxy mass, formation redshift of the progenitor system and different progenitor metallicities. I will show that the signal is dominated by binaries formed at the peak of star formation in massive galaxies with and binaries formed recently in dwarf galaxies. Then, I will present what very high resolution hydrodynamic simulations of different galaxy types can learn us about their black hole populations.
How Einstein’s Theory of Relativity Gives us and the Atomic Bomb
Authors: Henry Richard Conn 
Published: January 2019

AbstractThe LIGO direct-detection of gravitational waves arriving from cosmic sources—now, happily including (as of this meeting!) the merging of two neutron stars—opens a new chapter in our understanding of physics itself: for General Relativity, conceptually so extremely simple, has robustly produced predictions that have invariably been found to be correct when tested. My poster (page 3 of this paper) is intended for high school students who have just learned simple algebra. My derivation of the famous E = mc2 from the Pythagorean Theorem necessarily requires an algebraic expansion that is due to Newton, but apart from that it is simplicity itself: a transparent introduction to what all of physics is today: the construction of mathematics that, miraculously, reproduces our observations of the world—and which also successfully predicts the results of future observations—as so magnificently demonstrated at this glorious Symposium!
DESGW Optical Follow-up of BBH LIGO-Virgo Events with DECam
Authors: Butler Robert E. , Soares-Santos M. , Annis J. , Herner K. ,   for the Dark Energy Survey Gravitational Wave program and the DECam Community Group Collaboration
Published: January 2019

AbstractThe DESGW program is a collaboration between members of the Dark Energy Survey, the wider astronomical community, and the LIGO-Virgo Collaboration to search for optical counterparts of gravitational wave events, such as those expected from binary neutron star mergers or neutron star-black hole mergers. While binary black hole (BBH) events are not expected to produce an electromagnetic (EM) signature, emission is certainly not impossible. The DESGW program has performed follow-up observations of four BBH events detected by LIGO in order to search for any possible EM counterpart. Failure to find such counterparts is still relevant in that it produces limits on optical emission from such events. This is a review of follow-up results from O1 BBH events and a discussion of the status of ongoing uniform re-analysis of all BBH events that DESGW has followed up to date.
Strong-lensing of Gravitational Waves by Galaxy Clusters
Authors: Smith Graham P. , Berry Christopher , Bianconi Matteo , Farr Will M. , Jauzac Mathilde , Massey Richard , Richard Johan , Robertson Andrew , Sharon Keren , Vecchio Alberto , Veitch John 
Published: January 2019

AbstractDiscovery of strongly-lensed gravitational wave (GW) sources will unveil binary compact objects at higher redshifts and lower intrinsic luminosities than is possible without lensing. Such systems will yield unprecedented constraints on the mass distribution in galaxy clusters, measurements of the polarization of GWs, tests of General Relativity, and constraints on the Hubble parameter. Excited by these prospects, and intrigued by the presence of so-called “heavy black holes” in the early detections by LIGO-Virgo, we commenced a search for strongly-lensed GWs and possible electromagnetic counterparts in the latter stages of the second LIGO observing run (O2). Here, we summarise our calculation of the detection rate of strongly-lensed GWs, describe our review of BBH detections from O1, outline our observing strategy in O2, summarize our follow-up observations of GW170814, and discuss the future prospects of detection.
High power in Advanced LIGO
Authors: Hardwick Terra ,   for the LIGO Scientific Collaboration
Published: January 2019

AbstractThe LIGO detectors have just completed a successful and exciting observation run. Both facilities are now undergoing upgrades and commissioning, including doubling the circulating power in the interferometer which will increase LIGO’s sensitivity above 100 Hz. This paper motivates the power increase and discusses the problems in general that arise with higher power and the progress to date with addressing them. Topics include input power noise coupling, parametric instability, and thermal effects.
Vegetation and Climate Change in Southwestern Australia During the Last Glacial Maximum
Authors: Sniderman J. M. K. , Hellstrom J. , Woodhead J. D. , Drysdale R. N. , Bajo P. , Archer M. , Hatcher L. 
Published: January 2019

AbstractThe nature and duration of the Last Glacial Maximum (LGM) in Australia are poorly understood, with little regional agreement on the timing and direction of LGM climate changes. One reason for this is that Australian Late Pleistocene terrestrial sediments typically are both sparse and inorganic, inhibiting the development of detailed radiocarbon chronologies. To address this problem, we extracted fossil pollen from radiometrically dated stalagmites collected in southwest Western Australia. Our pollen record, supported by 30 U‐Th dates, reveals the vegetation response to Late Pleistocene climates between ~34 and 14 ka, through the body of the LGM. Before ~28 ka, sclerophyll forests were more open than today, but at ~28 ka forest cover was essentially eliminated, and treeless conditions were maintained until progressive reforestation at ~17.5 ka. This ~10‐ka‐long full glacial episode correlates with other mid‐high latitude Southern Hemisphere records, suggesting that LGM environmental changes were closely coordinated across the hemisphere.
The Potential of DAS in Teleseismic Studies: Insights From the Goldstone Experiment
Authors: Yu Chunquan , Zhan Zhongwen , Lindsey Nathaniel J. , Ajo‐Franklin Jonathan B. , Robertson Michelle 
Published: January 2019

AbstractDistributed acoustic sensing (DAS) is a recently developed technique that has demonstrated its utility in the oil and gas industry. Here we demonstrate the potential of DAS in teleseismic studies using the Goldstone OpticaL Fiber Seismic experiment in Goldstone, California. By analyzing teleseismic waveforms from the 10 January 2018 M7.5 Honduras earthquake recorded on ~5,000 DAS channels and the nearby broadband station GSC, we first compute receiver functions for DAS channels using the vertical‐component GSC velocity as an approximation for the incident source wavelet. The Moho P‐to‐s conversions are clearly visible on DAS receiver functions. We then derive meter‐scale arrival time measurements along the entire 20‐km‐long array. We are also able to measure path‐averaged Rayleigh wave group velocity and local Rayleigh wave phase velocity. The latter, however, has large uncertainties. Our study suggests that DAS will likely play an important role in many fields of passive seismology in the near future.
Persistent Hydrological Consequences of Hurricane Maria in Puerto Rico
Authors: Miller P. W. , Kumar A. , Mote T. L. , Moraes F. D. S. , Mishra D. R. 
Published: January 2019

AbstractIn September 2017, Hurricane Maria severely defoliated Puerto Rico's landscape, coinciding with a series of persistent hydrological consequences involving the atmospheric, terrestrial, and marine components of the water cycle. During the defoliated period, the atmosphere's thermodynamic structure more strongly explained daily cloud activity (R2PRE = 0.02; R2POST = 0.40) and precipitation (R2PRE = 0.19; R2POST = 0.33) than before landfall, indicating that post‐Maria land‐atmosphere interactions were comparatively muted, with similar precipitation patterns also found following Hurricanes Hugo (1989) and Georges (1998). Meanwhile, modeled post‐Maria runoff exceeded statistical expectations given the magnitude of contemporaneous precipitation. Enhanced runoff also coincided with greater sediment loads in nearshore waters, increasing sediment content greater than twofold. This study offers a holistic narrative of hydrospheric disturbance and recovery, whereby the instantaneous, large‐scale removal of vegetation is accompanied by hydrologic changes “upstream” in the atmosphere and “downstream” in rivers and estuaries.
Modulations of Saturn's UV Auroral Oval Location by Planetary Period Oscillations
Authors: Bader A. , Badman S.V. , Kinrade J. , Cowley S.W.H. , Provan G. , Pryor W. 
Published: January 2019

AbstractIt is well known that Saturn's magnetospheric dynamics are greatly influenced by the so‐called planetary period oscillations (PPOs). Based on Cassini Ultraviolet Imaging Spectrograph (UVIS) imagery, it has been shown previously that the UV auroral intensity is clearly modulated in phase with rotating field‐aligned current (FAC) systems associated with the PPOs. Here we expand upon this investigation by using the same data set to examine the PPO‐induced spatial modulation of the main auroral oval. We present a robust algorithm used for determining the location of the main emission in Cassini‐UVIS images. The location markers obtained are then used to calculate the statistical location of the auroral oval and its periodic displacement due to the PPO FACs and the related ionospheric flows. We find that the largest equatorward displacement of the main arc lags behind the PPO‐dependent statistical brightening of the UV aurora by roughly 45–90° in both hemispheres and is not colocated with it as the present model based on magnetometer observations suggests. We furthermore find the center of the auroral oval by fitting circles to the main emission and analyze its elliptic motion as the entire oval is displaced in phase with the PPO phases. It is demonstrated that the periodic displacements of both the auroral oval arc and its center are larger when the two PPO systems rotate in relative antiphase than when they are in phase, clearly indicating that interhemispheric PPO FAC closure modulates not only the intensity but also the location of the main UV auroral emission.
Global‐Scale ULF Waves Associated With SSC Accelerate Magnetospheric Ultrarelativistic Electrons
Authors: Hao Y. X. , Zong Q.‐G. , Zhou X.‐Z. , Rankin R. , Chen X. R. , Liu Y. , Fu S. Y. , Baker D. N. , Spence H. E. , Blake J. B. , Reeves G. D. , Claudepierre S. G. 
Published: January 2019

AbstractWe study electron behavior in the outer radiation belts during the 16 July 2017 storm sudden commencement (SSC), in which prompt intensification of ultrarelativistic electron fluxes was observed at around L = 4.8 by Van Allen Probe B immediately after an interplanetary shock. The electron fluxes in multiple energy channels show clear oscillations in the Pc5 frequency range, although the oscillation characteristics are quite different in different energy channels. At energies above ∼1 MeV, the oscillation periods were very close to the electron drift period, which resembles an energy spectrogram evolution expected for an energetic particle injection event and its drift echoes. At lower energies, however, the oscillation periods hardly depended on the energy: They were very close to the ultralow frequency (ULF) wave period derived from electric field measurements (about 250 s according to wavelet analysis). These complex signatures are consistent with the picture of drift resonance between electrons and short‐lived ULF waves with low azimuthal wave numbers. Good agreement between the observations and numerical simulations confirms that shock‐induced global‐scale ULF waves can efficiently accelerate outer belt ultrarelativistic electrons up to 3.4 MeV over a time scale shorter than 1 hr.
The Hall Electric Field in Earth's Magnetotail Thin Current Sheet
Authors: Lu San , Artemyev A. V. , Angelopoulos V. , Lin Y. , Zhang X.‐J. , Liu J. , Avanov L. A. , Giles B. L. , Russell C. T. , Strangeway R. J. 
Published: January 2019

AbstractOne of the most important properties of Earth's magnetotail thin current sheet (TCS) is that its current is predominantly contributed by magnetized electrons. The Hall electric field, normal to the TCS and generated by charge separation, is critical to the generation of this electron current as well as a dawn‐dusk asymmetry of the magnetotail, such as duskside preference of magnetic reconnection and related structures and phenomena. However, systematic investigation of the Hall electric field has so far been lacking. Utilizing observations of TCS by Magnetospheric Multiscale and Time History of Events and Macroscale Interactions during Substorm spacecraft, we study the properties of this field. Our results, from various, complementary methods, show that the Hall electric field Ez (in the geocentric solar magnetospheric, coordinate system) or En (normal to the TCS plane) can be clearly observed to point toward the center of the current sheet. The typical magnitude of this electric field is several tenths of 1 mV/m. Statistics of Magnetospheric Multiscale magnetotail TCS crossings show that the Hall electric field is stronger on the duskside, indicating a stronger Hall effect there, which confirms predictions from global‐scale hybrid and particle‐in‐cell simulations.
The Permeability of Volcanic Mixtures—Implications for Pyroclastic Currents
Authors: Breard Eric C. P. , Jones Jim R. , Fullard Luke , Lube Gert , Davies Clive , Dufek Josef 
Published: January 2019

AbstractGeophysical fluid‐granular flows, such as pyroclastic currents and debris flows, owe much of their runout and hazard behavior to the occurrence and time‐variant decay of a flow‐internal fluid pore pressure. However, modeling the effects of fluid pore pressure to forecast hazards is challenging because a unified method in Earth Sciences to quantitatively determine the permeability of these natural mixtures is currently missing. Here we combine experiments on fluidization and defluidization of pyroclastic materials, eolian sediments, and glass beads mixtures with numerical multiphase simulations to compare previous attempts to compute the permeability of complex natural particle‐fluid mixtures. In analogy to particle‐engineering studies on simple gas‐particle mixtures, we demonstrate that the effective length‐scale in the characterization of the fluid‐particle interaction of complex natural mixtures is the product of the Sauter mean diameter and the particle sphericity. Its use in the Kozeny‐Carman equation allows accurate prediction of mixture permeability, and we suggest the routine calculation of the Sauter mean from grain size distributions of the deposits of geophysical mass flows in Earth Sciences. We also show, through defluidization experiments, that the duration of gas retention in natural mixtures is well described when using the Sauter mean as the effective particle size. Further, we show through multiphase simulations that initial bed expansion extends the pore pressure diffusion timescale up to nine times. These results can be applied to small‐to‐large volume dense pyroclastic currents where the ranges of Sauter mean diameter predict gas retention for long duration and to debris flows and snow avalanches.
Constitutive Law for Earthquake Production Based on Rate‐and‐State Friction: Theory and Application of Interacting Sources
Authors: Heimisson Elías R. 
Published: January 2019

AbstractThe constitutive relationship of Dieterich (1994, https://doi.org/10.1029/93JB02581) for earthquake production has been applied widely to earthquake triggering. The Dieterich theory achieves mathematical simplicity and thus lends itself to practical applications through a number of simplifying assumptions. Perhaps the most suspect and criticized assumption is that seismic sources do not interact. Here I provide an extension of the constitutive framework, using the modified formulation of Heimisson and Segall (2018, https://doi.org/10.1029/2018JB015656) which accounts for source interactions. Moreover, I explore ways to account for earthquake magnitudes and highlight potential directions for future research. I identify conditions under which the constitutive relationship with interactions reduces to the noninteracting Dieterich theory, revealing that an interacting population may be modeled as an equivalent noninteracting population. This result may partly explain the success of the Dieterich theory in spite of assuming no interactions. These special conditions reveal that if the magnitude distribution (e.g., the b value) is altered by a stress perturbation, then the Dieterich model may either underpredict or overpredict the seismicity rate. Furthermore, the interaction model grants insight into the physical interpretation of the background seismicity rate, which is frequently considered to be a declustered rate. However, the results suggest that interactions do not change the total cumulative number of events over a long time span (t ≫ ta). Finally, I apply the interaction theory to fault slip models, aftershock diffusion, and secondary triggering as illustrative examples.
Assimilating INSAT‐3D Thermal Infrared Window Imager Observation With the Particle Filter: A Case Study for Vardah Cyclone
Authors: Kumar Prashant , Shukla Munn V. 
Published: January 2019

AbstractA big challenge in the satellite data assimilation is the effective use of InfraRed (IR) window channel radiances in the high‐resolution weather model. A hybrid data‐assimilation method is used in this study for very severe cyclonic storm “Vardah,” in which three‐dimensional variational method is used to assimilate control observations, and particle filter method is used to assimilate Indian geostationary satellite INSAT‐3D data. In the context of imperfect weather model, various particles (or ensembles) are prepared with different combinations of model physics. To implement particle filter, INSAT‐3D thermal IR window channel 1 (TIR‐1; center wavelength 11 μm) measured brightness temperature (BT) and cloud mask product are used to assign appropriate weights to different particles to reduce model uncertainties. This step is followed by resampling step in which new particles are generated from high weight particles using stochastic kinetic‐energy backscatter scheme method and dynamical variables are perturbed into the model physics. Results suggest that simulated TIR‐1 BT analysis and forecasts from WPF (with INSAT‐3D data using particle filter experiments) are closer to INSAT‐3D measured TIR‐1 BT in comparison to WCNT (without INSAT‐3D data using particle filter) experiments. Furthermore, approximately 10% to 50% improvements are found in mean track error forecasts in WPF experiments. An improvement of ~10% is noticed in cyclone center position in analysis. Prediction of storm intensity is also improved after assimilation. Results also suggest that vertical structure of WPF simulated humidity, temperature, wind speed, and surface pressure is improved over WCNT runs.