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Extreme variations in the direction of Earth’s magnetic field contain important information regarding the operation of the geodynamo. Paleomagnetic studies have reported rapid directional changes reaching 1° yr −1 , although the observations are controversial and their relation to physical processes in Earth’s core unknown. Here we show excellent agreement between amplitudes and latitude ranges of extreme directional changes in a suite of geodynamo simulations and a recent observational field model spanning the past 100 kyrs. Remarkably, maximum rates of directional change reach  ~10° yr −1 , typically during times of decreasing field strength, almost 100 times faster than current changes. Detailed analysis of the simulations and a simple analogue model indicate that extreme directional changes are associated with movement of reversed flux across the core surface. Our results demonstrate that such rapid variations are compatible with the physics of the dynamo process and suggest that future searches for rapid directional changes should focus on low latitudes. The authors here use numerical simulations combined with a time-dependent model of Earth’s magnetic field spanning the last 100 kyrs. They identify field directional changes to be 10 times faster than previously thought.

Previous studies of rapid geomagnetic changes have highlighted the most extreme changes in direction and field strength found in paleomagnetic field models over the past 100 ky. Here we study distributions of rates of change in both time and space. Field models based on direct observations provide the most accurate values for rates of change, but their short duration precludes a complete description of field behavior. Broader representation is provided by time‐varying paleofield models, here including GGF100k, GGFSS70, LSMOD.2, CALS10k.2, HFM.OL1.A1, pfm9k.2, and SHAWQ‐iron age although variability across models and lack of temporal and spatial resolution of fine scale variations make direct comparisons difficult. For the paleofield we define rapid changes as exceeding the peak overall value of 0.4° yr−1 for directional changes and 150 nT yr−1 for intensities as established by the gufm1 model spanning 1590–1990 CE. We find that rapid directional changes are associated with low field strength and can spread across all latitudes during such episodes. Distributions of directional rates of change exhibit high skewness for models that include excursions. Rates of change in field intensity exceeding 150 nT yr−1 arise in brief intervals during the Holocene particularly associated with the strong field Levantine Iron Age Anomaly. Around the Laschamp excursion there are also rare localized occurrences of rapid intensity change. Limitations in current models make it difficult to define absolute rates for past changes, but we see that rapid changes are essential field characteristics not observed in the modern field that should nevertheless be regarded as an essential for Earth‐like dynamo simulations. Plain Language Summary Earth's magnetic field is generated by fluid motions in its liquid outer core lying deep below the surface. Changes in the modern field are well‐mapped using low earth orbiting satellites and ground observations, but these are very modest. The largest changes over the past hundred thousand years occur on geological time scales predating the era of direct observations. These include geomagnetic excursions, periods characterized by low field strength and unstable directions, and intensity spikes when the field is unusually strong. To study the rates at which field changes occur we use a range of global time‐varying magnetic field models constructed from paleomagnetic and archeomagnetic records. These are much less detailed than modern data, but after accounting for their lesser resolution can still provide key insights into the occurrence of the most rapid changes. We find that high rates of change are an essential characteristic of the geomagnetic field over 0–100 ka that should be reproducible in Earth‐like dynamo simulations. Anomalously large rates of directional change are associated with weak field intensities surrounding geomagnetic excursions. Rapid intensity changes occur in brief intervals associated with the strongest fields found during the past few thousand years. Key Points Rapid changes are an essential characteristic of the geomagnetic field over 0–100 ka Anomalously large rates of directional change are associated with weak field intensity Rapid intensity changes occur in brief intervals associated with strong fields

Extreme variations of Earth’s magnetic field occurred in the Levant region around 1000 BC, when the field intensity rapidly rose and fell by a factor of 2. No coherent link currently exists between this intensity spike and the global field produced by the core geodynamo. Here we show that the Levantine spike must span >60° longitude at Earth’s surface if it originates from the core–mantle boundary (CMB). Several low intensity data are incompatible with this geometric bound, though age uncertainties suggest these data could have sampled the field before the spike emerged. Models that best satisfy energetic and geometric constraints produce CMB spikes 8–22° wide, peaking at O(100) mT. We suggest that the Levantine spike reflects an intense CMB flux patch that grew in place before migrating northwest, contributing to growth of the dipole field. Estimates of Ohmic heating suggest that diffusive processes likely govern the ultimate decay of geomagnetic spikes. Rapid and spatially localized geomagnetic field variations around 1000 BC are hard to reconcile with expected field behaviour arising from the core dynamo. Here, the authors show that the intensity spike is consistent with an intense flux patch on the core-mantle boundary (8–22°) located under Saudi Arabia.

Background GEOMAGIA50.v3 is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data from a variety of materials that record Earth’s magnetic field over the past 50 ka. Findings Since its original release in 2006, the structure and function of the database have been updated and a significant number of data have been added. Notable modifications are the following: (1) the inclusion of additional intensity, directional and metadata from archeological and volcanic materials and an improved documentation of radiocarbon dates; (2) a new data model to accommodate paleomagnetic, rock magnetic, and chronological data from lake and marine sediments; (3) a refinement of the geographic constraints in the archeomagnetic/volcanic query allowing selection of particular locations; (4) more flexible methodological and statistical constraints in the archeomagnetic/volcanic query; (5) the calculation of predictions of the Holocene geomagnetic field from a series of time varying global field models; (6) searchable reference lists; and (7) an updated web interface. This paper describes general modifications to the database and specific aspects of the archeomagnetic and volcanic database. The reader is referred to a companion publication for a description of the sediment database. Conclusions The archeomagnetic and volcanic part of GEOMAGIA50.v3 currently contains 14,645 data (declination, inclination, and paleointensity) from 461 studies published between 1959 and 2014. We review the paleomagnetic methods used to obtain these data and discuss applications of the data within the database. The database continues to expand as legacy data are added and new studies published. The web-based interface can be found at http://geomagia.gfz-potsdam.de .

Background GEOMAGIA50.v3 for sediments is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data obtained from lake and marine sediments deposited over the past 50 ka. Its objective is to catalogue data that will improve our understanding of changes in the geomagnetic field, physical environments, and climate. Findings GEOMAGIA50.v3 for sediments builds upon the structure of the pre-existing GEOMAGIA50 database for magnetic data from archeological and volcanic materials. A strong emphasis has been placed on the storage of geochronological data, and it is the first magnetic archive that includes comprehensive radiocarbon age data from sediments. The database will be updated as new sediment data become available. Conclusions The web-based interface for the sediment database is located at http://geomagia.gfz-potsdam.de/geomagiav3/SDquery.php . This paper is a companion to Brown et al. (Earth Planets Space doi:10.1186/s40623-015-0232-0, 2015) and describes the data types, structure, and functionality of the sediment database.

Adapting Philosophy looks at the ways in which The Matrix Trilogy adapts Jean Baudrillard’s Simulacra and Simulation, and in doing so creates its own distinctive philosophical position. Where previous work in the field has presented the trilogy as a simple ‘beginner’s guide’ to philosophy, this study offers a new methodology for inter-relating philosophy and film texts, focusing on the conceptual role played by imagery in both types of text. This focus on the figurative enables a new-found appreciation of the liveliness of philosophical writing and the multiple philosophical dimensions of Hollywood films. The book opens with a critical overview of existing philosophical writing on The Matrix Trilogy and goes on to draw on adaptation theory and feminist philosophy in order to create a new methodology for interlinking philosophical and filmic texts. Three chapters are devoted to detailed textual analyses of the films, tracing the ways in which the imagery that dominates Baudrillard’s writing is adapted and transformed by the trilogy’s complex visuals and soundtrack. The conclusion situates the methodology developed throughout the book in relation to other approaches currently emerging in the new field of Film-Philosophy. The book’s multi-disciplinary approach encompasses Philosophy, Film Studies and Adaptation Theory and will be of interest to undergraduates and postgraduates studying these subjects. It also forms part of the developing interdisciplinary field of Film-Philosophy. The detailed textual analyses of The Matrix Trilogy will also be of interest to anyone wishing to deepen their understanding of the multi-faceted nature of this seminal work.

The natural spectrum of electromagnetic variations surrounding Earth extends across an enormous frequency range and is controlled by diverse physical processes. Electromagnetic (EM) induction studies make use of external field variations with frequencies ranging from the solar cycle which has been used for geomagnetic depth sounding through the 10 - 4 –10 4  Hz frequency band widely used for magnetotelluric and audio-magnetotelluric studies. Above 10 4  Hz, the EM spectrum is dominated by man-made signals. This review emphasizes electromagnetic sources at ∼ 1 Hz and higher, describing major differences in physical origin and structure of short- and long-period signals. The essential role of Earth’s internal magnetic field in defining the magnetosphere through its interactions with the solar wind and interplanetary magnetic field is briefly outlined. At its lower boundary, the magnetosphere is engaged in two-way interactions with the underlying ionosphere and neutral atmosphere. Extremely low-frequency (3 Hz–3 kHz) electromagnetic signals are generated in the form of sferics, lightning, and whistlers which can extend to frequencies as high as the VLF range (3–30 kHz).The roughly spherical dielectric cavity bounded by the ground and the ionosphere produces the Schumann resonance at around 8 Hz and its harmonics. A transverse resonance also occurs at 1.7–2.0 kHz arising from reflection off the variable height lower boundary of the ionosphere and exhibiting line splitting due to three-dimensional structure. Ground and satellite observations are discussed in the light of their contributions to understanding the global electric circuit and for EM induction studies.

Vaccines for two viruses which cause cancer, human papillomavirus (HPV) and hepatitis B virus (HBV), are recommended for all children in the United States. Numerous parallels exist between the two vaccines in addition to their roles in cancer prevention, including transmission through sexual contact, multiple doses needed for series completion, and vaccine administration in adolescence for HPV and in the initial phase of the HBV vaccination program. All of these factors were viewed as potential barriers to achieving high rates of coverage, yet the ultimate success of the HBV vaccination program led to predictions that similarly high rates of coverage could be achieved for the HPV vaccine. However, currently, only the recommendation for HBV vaccination is supported by mandates for school entry in most states. Uptake of the HPV vaccine has lagged far behind U.S. goals for public health promotion. The aim of this paper is to examine factors which may account for the divergent pathways of the two vaccines. Four main factors are identified: logistical challenges of vaccine administration, attitudes of parents and healthcare providers, safety concerns, and cost. For each factor examined, recommendations are offered to confront similar barriers likely to arise for future vaccines. The authors conclude that gender-neutral state mandates coupled with school-located vaccination programs, stronger gender-neutral messaging from pharmaceutical companies and healthcare providers, and younger age of vaccine administration, if approved, present the most promising approaches to improving uptake of the HPV vaccine, and similar vaccines down the road.

Adapting Philosophy looks at the ways in which The Matrix Trilogy adapts Jean Baudrillard's Simulacra and Simulation, and in doing so creates its own distinctive philosophical position. Where previous work in the field has presented the trilogy as a simple 'beginner's guide' to philosophy, this study offers a new methodology for inter-relating philosophy and film texts, focusing on the conceptual role played by imagery in both types of text. This focus on the figurative enables a new-found appreciation of the liveliness of philosophical writing and the multiple philosophical dimensions of Hollywood films. The book opens with a critical overview of existing philosophical writing on The Matrix Trilogy and goes on to draw on adaptation theory and feminist philosophy in order to create a new methodology for interlinking philosophical and filmic texts. Three chapters are devoted to detailed textual analyses of the films, tracing the ways in which the imagery that dominates Baudrillard's writing is adapted and transformed by the trilogy's complex visuals and soundtrack. The conclusion situates the methodology developed throughout the book in relation to other approaches currently emerging in the new field of Film-Philosophy. The book's multi-disciplinary approach encompasses Philosophy, Film Studies and Adaptation Theory and will be of interest to undergraduates and postgraduates studying these subjects. It also forms part of the developing interdisciplinary field of Film-Philosophy. The detailed textual analyses of The Matrix Trilogy will also be of interest to anyone wishing to deepen their understanding of the multi-faceted nature of this seminal work.