bluuebunny/crossref_metadata_2025_split huggingface dataset:
The interplay among clast size, vesicularity, postfragmentation expansion, and clast breakage: An example from the 1.8 ka Taupo eruption
Authors: Mitchell S.J. , Biass S. , Houghton* B.F. , Anderson A. , Bonny E. , Walker B.H. , Mintz B.G. , Turner N.R. , Frank D. , Carey R.J. , Rosenberg M.D. 
Published: October 2019

ABSTRACT
Field studies of tephra-fall deposits traditionally use the density of juvenile pyroclasts to determine vesicularity of the host magma at the point of fragmentation. A range of pyroclast sizes between 16 and 32 mm has commonly been chosen for this purpose. Larger pyroclasts outside this range may undergo postfragmentation vesiculation due to slow cooling of the interior of the clasts, while smaller pyroclasts may be too small to represent accurately the distribution of the largest vesicles. The assumption of this method, of course, is that the 16–32 mm size range is representative of the fragmented magma. We explore, in detail, variations in density over a size range of 4–128 mm from Unit 2 pyroclasts of the 1.8 ka Taupo eruption and make inferences about the roles of postfragmentation vesiculation and secondary breakage of pyroclasts. We find (1) there is a clear threshold for onset of postfragmentation vesiculation at &gt;32 mm, and (2) there are broken small pieces of the largest pyroclasts in the sample that artificially skew the density distribution for smaller size fractions. We constrain uncertainty associated with vesicularity measurements and offer best-practice recommendations in the hope of improving consistency of field sampling and laboratory processing of pyroclast populations for vesicularity studies.
A review of the Earth history record in the Cretaceous, Paleogene, and Neogene pelagic carbonates of the Umbria-Marche Apennines (Italy): Twenty-five years of the Geological Observatory of Coldigioco
Authors: Alvarez Walter 
Published: October 2019

ABSTRACT
The Cretaceous and Paleogene pelagic limestone and marl formations of the Umbria-Marche Apennines of north-central Italy have proven to be exceptional recorders of the history of Earth and of life on Earth, and they have been the subject of numerous geological and paleontological studies over the last several decades. Founded a quarter century ago, in 1992, the Geological Observatory of Coldigioco is a research and teaching center focused on these exceptional rocks. This chapter is a historical introduction that briefly reviews the highlights of the lithologic, biostratigraphic, sedimentologic, magnetostratigraphic, impact-stratigraphic, geochemical, geochronological, time-scale, and cyclostratigraphical research done on the Umbria-Marche stratigraphic sequence, much of it facilitated by the Geological Observatory of Coldigioco. This review covers work up to the Coldigioco 25th anniversary Penrose conference in September 2017; it does not treat work presented at that conference or done since then. A remarkable irony is that a century ago, the Umbria-Marche Cretaceous–Paleogene sequence was so difficult to date that early work contained an error of ~35 m.y., but now there is a reasonable hope that this entire section may eventually be dated to an accuracy and precision of ~10,000 yr. This review begins with an homage to the little medieval city of Gubbio, its wild Festa dei Ceri, and its Bottaccione Gorge, where much of the research described here has been done. The review ends with three points of perspective. The first is the notion that sometimes geology can be done by looking up at the sky, and astronomy can be done by looking down at Earth, with much of the Coldigioco-based research being of this latter kind. The second is the observation that geology and paleontology are contributing far more new information to Big History—to our integrated knowledge of the past—than any other historical field in the humanities or sciences. The third is that three of the major scientific revolutions of geology in the twentieth century have direct connections to the Umbria-Marche stratigraphic sequence—the turbidite revolution, the development of plate tectonics, and the downfall of strict uniformitarianism.
Cyclostratigraphic investigations in the Calcare Massiccio (Early Jurassic, Umbria-Marche Basin) through photogrammetry
Authors: Penasa Luca , Franceschi* Marco , Gattolin Giovanni , Preto Nereo , Deseilligny Marc-Pierrot , Montanari Alessandro 
Published: October 2019

ABSTRACT
In this paper, we present a case study to demonstrate the potential of photogrammetry in cyclostratigraphic applications. To this end, we considered an ~300-m-thick section exposing the Lower Jurassic Calcare Massiccio Formation in the Marche Apennines of central Italy. The Calcare Massiccio comprises a thick succession of peritidal shallow-water carbonates displaying a prominent sedimentary cyclicity, where supratidal and subtidal facies alternate. The section investigated in this study is exposed on the wall of an active quarry and is almost completely inaccessible because it is vertical and because of safety and liability regulations. This setting prevents the application of standard sampling and facies analysis techniques on the whole series. An accurate three-dimensional model of the quarry wall was therefore produced by processing ~360 digital images through photogrammetry and generating a high-resolution (centimeter-scale) point cloud of the outcrop with red-green-blue (RGB) values associated with each point. An ~150-m-long log representing color variations on a continuous portion of the exposed succession was then extracted from the point cloud by converting the original RGB values to grayscale values. The main facies were directly investigated in an ~10-m-long accessible section that was logged and sampled, and it was established that supratidal facies with planar stromatolites and teepee structures are darker in color, while subtidal facies, made of bioturbated mudstones to floatstones with gastropods and oncoids, display lighter color. This provided ground-truth data with which to interpret the grayscale variations in terms of facies alternations. Time-series analysis was then carried out on the grayscale series, and this revealed prominent cyclicities. Because the biochronostratigraphic framework of the Calcare Massiccio is poor, the potential orbital origin of these frequencies was tested with the average spectral misfit technique. Preliminary results suggest that the observed spectral features are compatible with Milankovitch periods and that astronomical forcing might have been a major driver in the deposition of the Calcare Massiccio Formation. Furthermore, they testify to the great potential of photogrammetry in cyclostratigraphic applications, especially when large-scale, inaccessible outcrops have to be investigated.
Multiproxy Cretaceous-Paleogene boundary event stratigraphy: An Umbria-Marche basinwide perspective
Authors: Sinnesael Matthias , Montanari Alessandro , Frontalini Fabrizio , Coccioni Rodolfo , Gattacceca Jérôme , Snoeck Christophe , Wegner Wencke , Koeberl Christian , Morgan Leah E. , Winter Niels J. de , DePaolo Donald J. , Claeys Philippe 
Published: October 2019

ABSTRACT
The complete and well-studied pelagic carbonate successions from the Umbria-Marche basin (Italy) permit the study of the event-rich stratigraphic interval around the Cretaceous-Paleogene boundary (e.g., Deccan volcanism, boundary impact, Paleocene recovery, and climate). To test the robustness of various proxy records (bulk carbonate δ13C, δ18O, 87Sr/86Sr, and Ca, Fe, Sr, and Mn concentrations) inside the Umbria-Marche basin, several stratigraphically equivalent sections were investigated (Bottaccione Gorge, Contessa Highway, Fornaci East quarry, Frontale, Morello, and Petriccio core). Besides the classical Gubbio sections of Bottaccione and Contessa, the new Morello section is put forward as an alternative location for this stratigraphic interval because it is less altered by burial diagenesis. Elemental profiles (Ca, Fe, Sr, Mn) acquired by handheld X-ray fluorescence (pXRF) efficiently provide regional chemostratigraphic and paleoenvironmental information. The Deccan volcanism, the Cretaceous-Paleogene boundary, the characteristic pattern of the Sr/Ca profile across the boundary driven by the extinction and recovery of coccolithophores, and the Dan-C2 hyperthermal event are examples of such recorded paleoenvironmental events. Moreover, cyclostratigraphic analyses of proxies of detrital input (magnetic susceptibility and Fe concentrations) show the imprint in the sedimentary record of a 2.4 m.y. eccentricity minimum around 66.45–66.25 Ma, and suggest that the occurrence of the Dan-C2 hyperthermal event was astronomically paced.
Expansion breccias in Lower Cretaceous Apennine pelagic limestones: I. Geological observations
Authors: Alvarez* Walter , Belza Joke , Chan Lung S. , Claeys Philippe , Geiser Peter , Menichetti Marco , Shimabukuro David H. , Tavarnelli Enrico 
Published: October 2019

ABSTRACT
Breccias affecting the pelagic Lower Cretaceous Maiolica limestone of the Umbria-Marche Apennines of central Italy contain 10-cm-diameter to submillimeter angular clasts of white pelagic limestone and black chert, separated by a filling of sparry calcite. The clasts can often be seen to have originally fitted together, indicating extension without shear, and this is the case in all three dimensions, arguing for roughly isotropic volumetric expansion. Breccia fragments are separated by sparry calcite bodies comparable in width to the fragments; this shows that the breccias were not formed by collapse, or by a single large explosion, after either of which the fragments would surely have fallen to the bottom of the cavity, but probably by multiple small expansion events, each followed by calcite deposition in the small voids that opened up. The breccia sometimes occurs in dramatic topographic walls, a few tens of meters in both width and height, although there is not a one-to-one correspondence between breccia and walls. The sparry-calcite fill indicates that water with dissolved CO2 was involved in formation of the breccias, presumably providing the high fluid pressure that forced the fragments apart. The breccia is bounded stratigraphically above by the middle Cretaceous Marne a Fucoidi (Fucoid marls), which appears to represent an aquiclude that limited the volume of high fluid pressure (PF). Although the mechanism of formation of the expansion breccias is not yet clear, we list observations that need to be accounted for by such a mechanism and discuss how these observations might be explained.
Cretaceous-Paleogene boundary tsunamite on the Adriatic carbonate platform and possible source of a hypothetical Atlantic-to-western-Tethys megatsunami
Authors: Korbar* Tvrtko 
Published: October 2019

ABSTRACT
An unusual deposit at the Cretaceous-Paleogene (K-Pg) boundary within the Adriatic carbonate platform shallow-water succession is interpreted as a major tsunamite, and a possible mechanism that links it to the Chicxulub asteroid impact on Yucatan (Mexico) is speculated. Although the K-Pg boundary hiatus is a common feature within the shallow-marine successions of the Adriatic carbonate platform, three exceptional sections were discovered that are characterized by continuous sedimentation and the event beds at the K-Pg boundary. Two sections include ~5-m-thick coarse-grained complex event beds intercalated within more than 100-m-thick successions of predominantly micritic carbonates deposited in the protected low-energy inner-platform setting, relatively proximal to the platform-margin embayments. The third section is characterized by an ~10-cm-thick event bed showing distinct soft-sediment bioturbation, and it is interpreted as a more distal section. It has been reported previously that the Chicxulub impact cratering generated an almost global tsunami, while the seismic waves caused collapses of the North American southeastern margins. It is hypothesized that the collapses could have generated a megatsunami in the Atlantic Ocean that could pass through a deep seaway between the Atlantic and western Tethys Oceans and finally terminate on the Adriatic carbonate platform, located ~10,000 km from the impact site. Considering the fact that there are potential sedimentological indications for such a huge sedimentary event in NW Africa (Morocco), focused research is needed in the region, along with landslide tsunami modeling, for a relevant evaluation of the hypothesis.
Reconnaissance reassessment of the late Eocene Oceanic unit, Barbados: Microtektite geochemistry, zircon U-Pb geochronology, micropaleontology, and provenance
Authors: Weber* John , Wilson† Brent , Koeberl Christian , O’Sullivan Paul , Donelick Ray , Posner§ Esther S. 
Published: October 2019

ABSTRACT
We measured stratigraphic sections and collected samples from Oceanic suite outcrops at Gay’s Cove and Bath Cliffs, Barbados, in order to restudy the late Eocene microtektite layer(s) and provide new geological context. We disaggregated and processed samples into separates of microfossils, microtektites, and heavy minerals, and we present up-to-date glass geochemistry, biostratigraphic analysis, and detrital zircon U-Pb analysis. Results from the new Barbadian microtektite glass chemistry analysis (Gay’s Cove) compare well with those from other published microtektite analyses, as well as those from the correlative North American strewn field. Micropaleontology confirms a late Eocene age for the Oceanic microtektite horizon at Gay’s Cove. Using U-Pb, we dated 24 Tertiary zircon grains, probably from volcanic ash-fall events, which at Gay’s Cove yielded a preliminary, poorly defined, and incorrect depositional age for the microtektite layer (≤31.84 ± 0.85 Ma; weighted mean of only three grains). Three additional new U-Pb depositional ages (≤38.52 ± 1.0 Ma, ≤39.23 ± 0.3 Ma, ≤35.25 ± 0.82 Ma) were obtained from bottom to top in the 24 m section at Bath Cliffs. We also dated 46 Paleozoic–Proterozoic zircon grains using U-Pb and discuss whether these “old” grains represent recycled (subducted and extruded) volcanic grains or windblown silt/sand from Africa.
Late Pleistocene tectonic tilting of the Frasassi anticline from offset stalagmites in the Grotta Grande del Vento (Marche, Italy)
Authors: Bice David , Lacroce Michael , McGee David , Montanari Alessandro 
Published: October 2019

ABSTRACT
The massive Jurassic limestone making up the core of the Frasassi-Valmontagnana blind thrust anticline hosts a large sulfidic cave complex, which, due to Pleistocene tectonic uplift, has been incised by the Sentino River, forming the deep Frasassi Gorge. The Frasassi cave complex is organized into seven horizontal levels, with the youngest and presently active one at river level, and the oldest (ca. 1.2 Ma) one some 200 m above the Sentino River. Therefore, the Frasassi cave complex records the river incision history of this still-active Apennine mountain belt. In addition to an uplift rate of ~0.55 mm/yr for the Holocene, previous radioisotopic dating and surveying of phreatic calcite deposits revealed an overall tilting of the Frasassi anticline of ~0.2° toward N60E for the past 9000 or so years. Our study adds to this history of tectonic tilting by focusing on a group of 30 tilted stalagmites found at the bottom of the Abisso Ancona of the Grotta Grande del Vento (the largest room in the Frasassi complex). These stalagmites have a fairly uniform plunge of ~81° trending toward N30W, and we interpret this to record a tilt of the cave toward S30E during the formation of the stalagmites. From U-Th dating of these paleotiltmeters, we deduce that the Frasassi anticline was tilted by ~0.3° from 32 to 7 k.y. B.P., and the tilt rate gradually increased during this period. The 60° (NE) direction of oblique-slip faults in this area and the local focal mechanisms of recent seismic activity suggest that the tilting is caused by movement along a listric oblique strike-slip zone south of the Frasassi anticline. Our findings also demonstrate that given the right conditions, stalagmites can be used as paleotiltmeters that provide insight into recent crustal deformation.
Provenance studies of amphorae from the Greek colony Pharos on the island of Hvar, Croatia
Authors: Miše*,† Maja , Serneels† V. , Matana† A. , Montanari† A. , Kirigin† B. 
Published: October 2019

ABSTRACT
We present the results of a compositional characterization study of amphorae from the ancient Greek town of Pharos, today Stari Grad, on the island of Hvar, in central Dalmatia, Croatia. The aim of the study was to identify the provenance of amphorae unearthed in Pharos, to determine the locally produced amphorae, and to identify the provenance of imported amphorae with a scientific-based approach, using optical thin-section petrography and bulk geochemical analysis by wavelength-dispersive X-ray fluorescence on 19 samples of different types of amphorae and reference materials. The results of the analyses allowed us to identify a group of imported amphorae from Corinth or Corfu and a group of imported amphorae from southern Italy, probably from Calabria. We were also able to identify a third group of imported amphorae from an as-yet-unknown provenance/workshop. Finally, according to the geochemical composition and close match with the reference material, namely, kitchenware, only two amphorae from the examined collection could be identified as local products. The results of the compositional characterization of amphorae from Pharos show us that an ancient Greek town had trade contacts beyond the Adriatic-Ionian region, and they provide opportunities for further studies of ancient amphorae production and circulation in this part of the Mediterranean.
Educational attainment in childhood cancer survivors: a meta-analysis
Authors: Saatci Defne , Thomas Andrew , Botting Beverley , Sutcliffe Alastair G 
Published: October 2019

ObjectiveTo assess differences across educational outcomes in survivors of childhood cancer (CCS) compared with peers.DesignSystematic review and meta-analysis of observational studies.Data sources and study selectionMedline, EMBASE, ERIC, CINAHL and PsycInfo from inception to 1st August 2018. Any peer reviewed, comparative study with a population of any survivor of childhood cancer, from high-economy countries, reporting outcomes on educational attainment, were selected.Results26 studies representing 28 434 CCS, 17 814 matched controls, 6582 siblings and six population studies from 11 high-income countries, which have similar access to education and years of mandatory schooling as reported by the Organisation for Economic Cooperation and Development, were included. CCS were more likely to remain at compulsory level (OR 1.36, 95% CI 1.26 to 1.43) and less likely to complete secondary (OR 0.93, 95% CI 0.87 to 1.0) and tertiary level education (OR 0.87, 95% CI 0.78 to 0.98). They were more likely to require special educational needs (OR 2.47, 95% CI 1.91 to 3.20). Subgroup analyses revealed that survivors, irrespective of central nervous system (CNS) involvement, were less likely to progress onto secondary level compared with cancer-free peers (OR 1.77. 95% CI 1.46 to 2.15; OR 1.19, 95% CI 1.00 to 1.42, respectively). This, however, changed at tertiary level where those with CNS involvement continued to perform worse (OR 0.61, 95% CI 0.55 to 0.68) but those without appeared to perform similarly to their peers (OR 1.12, 95% CI 1.0 to 1.25).ConclusionsCompared with controls, we have elucidated significant differences in educational attainment in survivors. This is sustained across different countries, making it an international issue. CNS involvement plays a key role in educational achievement. Clinicians, teachers and policymakers should be made aware of differences and consider advocating for early educational support for survivors.
Nationwide trends in the epidemiology of diabetic foot complications and lower-extremity amputation over an 8-year period
Authors: Lin Cheng-Wei , Armstrong David G , Lin Chia-Hung , Liu Pi-Hua , Hung Shih-Yuan , Lee Shu-Ru , Huang Chung-Huei , Huang Yu-Yao 
Published: October 2019

ObjectiveTo study the prevalence and trends of lower extremity complications of diabetes over an 8-year period in a single nation.Research design and methodsNationwide data for people with type 2 diabetes (T2D) and diabetic foot complications (DFCs) were analyzed over an 8-year period (2007–2014) from National Health Insurance Research Database using the International Classification of Diseases, Ninth Revision disease coding. The DFCs were defined as ulcers, infections, gangrene, and hospitalization for peripheral arterial disease (PAD). Trends of patient characteristics, foot presentation, and the execution of major procedures were studied, including lower-extremity amputations (LEAs).ResultsAlong with the T2D population increasing over time, the absolute number of people with DFCs increased by 33.4%, but retained a prevalence of around 2% per year. The annual incident of LEAs decreased from 2.85 to 2.06 per 1000 T2D population (p=0.001) with the major LEA proportion decreasing from 56.2% to 47.4% (p<0.001).The mean age of patients increased from 65.3 to 66.3 years and most of the associated comorbidities of diabetes were increased. For example, end-stage renal disease increased from 4.9% to 7.7% (p=0.008). The incidence of gangrene on presentation decreased from 14.7% to 11.3% (p<0.001) with a concomitant increase in vascular interventions (6.2% to 19.5%, p<0.001).ConclusionsDFCs remain a sustained major medical problem. These nationwide long-term data suggest trends toward older people with greater comorbidities such as PAD and renal disease. Nevertheless, promising trends of reducing gangrene on presentation paired with increases in vascular interventions support continued vigilance and rapid, coordinated interdisciplinary diabetic foot care.
Validity of sample sizes in publications of randomised controlled trials on the treatment of age-related macular degeneration: cross-sectional evaluation
Authors: Tulka Sabrina , Geis Berit , Baulig Christine , Knippschild Stephanie , Krummenauer Frank 
Published: October 2019

ObjectiveThe aim of this cross-sectional study was to examine the completeness and accuracy of the reporting of sample size calculations in randomised controlled trial (RCT) publications on the treatment of age-related macular degeneration (AMD).MethodsA sample of 97 RCTs published between 2004 and 2014 was reviewed for the calculation of their sample size. It was examined whether a (complete) description of the sample size calculation was presented. Furthermore, the sample size was recalculated, whenever possible based on the published details, in order to verify the reported number of patients.Primary outcome measureThe primary endpoint of this cross-sectional investigation was a described sample size calculation that was reproducible, complete and correct (maximum tolerated deviation between reported and replicated sample size ±2 participants per trial arm).ResultsA total of 50 publications (52%) did not provide any information on the justification of the number of patients included. Only 17 publications (18%) provided all the necessary parameters for recalculation; 8 of 97 (8%, 95%-CI: 4% to 16%) publications achieved the primary endpoint. The median relative deviation between reported and recalculated sample sizes was 1%, with a range from −43% to +66%.ConclusionAlthough a transparent sample size legitimation is a crucial determinant of an RCT’s methodological validity, more than half of the RCT publications considered failed to report them. Furthermore, reported sample size legitimations were often incomplete or incorrect. In summary, clinical authors should pay more attention to the transparent reporting of sample size calculation, and clinical journal reviewers may opt to reproduce reported sample size calculations.SynopsisMore than half of the analysed RCT publications on the treatment of AMD did not report a transparent sample size calculation. Only 8% reported a complete and correct sample size calculation.