bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthetically modified guide RNA and donor DNA are a versatile platform for CRISPR-Cas9 engineering
Authors: Lee Kunwoo , Mackley Vanessa A , Rao Anirudh , Chong Anthony T , Dewitt Mark A , Corn Jacob E , Murthy Niren
Published: May 2017

Chemical modification of the gRNA and donor DNA has great potential for improving the gene editing efficiency of Cas9 and Cpf1, but has not been investigated extensively. In this report, we demonstrate that the gRNAs of Cas9 and Cpf1, and donor DNA can be chemically modified at their terminal positions without losing activity. Moreover, we show that 5’ fluorescently labeled donor DNA can be used as a marker to enrich HDR edited cells by a factor of two through cell sorting. In addition, we demonstrate that the gRNA and donor DNA can be directly conjugated together into one molecule, and show that this gRNA-donor DNA conjugate is three times better at transfecting cells and inducing HDR, with cationic polymers, than unconjugated gRNA and donor DNA. The tolerance of the gRNA and donor DNA to chemical modifications has the potential to enable new strategies for genome engineering.
A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis
Authors: Edens Brittany M , Yan Jianhua , Miller Nimrod , Deng Han-Xiang , Siddique Teepu , Ma Yongchao C
Published: May 2017

The etiological underpinnings of amyotrophic lateral sclerosis (ALS) are complex and incompletely understood, although contributions to pathogenesis by regulators of proteolytic pathways have become increasingly apparent. Here, we present a novel variant in UBQLN4 that is associated with ALS and show that its expression compromises motor axon morphogenesis in mouse motor neurons and in zebrafish. We further demonstrate that the ALS-associated UBQLN4 variant impairs proteasomal function, and identify the Wnt signaling pathway effector beta-catenin as a UBQLN4 substrate. Inhibition of beta-catenin function rescues the UBQLN4 variant-induced motor axon phenotypes. These findings provide a strong link between the regulation of axonal morphogenesis and a new ALS-associated gene variant mediated by protein degradation pathways.
Tuberculosis innovations mean little if they cannot save lives
Authors: Pai Madhukar , Furin Jennifer
Published: May 2017

The past decade has seen the emergence of new diagnostics and drugs for tuberculosis, a disease that kills over 1.8 million people each year. However, these new tools are yet to reach scale, and access remains a major challenge for patients in low and middle income countries. Urgent action is needed if we are committed to ending the TB epidemic. This means raising the level of ambition, embracing innovation, increasing financial investments, addressing implementation gaps, and ensuring that new technologies reach those who need them to survive. Otherwise, the promise of innovative technologies will never be realized.
Osteology ofGaleamopus pabstisp. nov. (Sauropoda: Diplodocidae), with implications for neurocentral closure timing, and the cervico-dorsal transition in diplodocids
Authors: Tschopp Emanuel , Mateus Octávio
Published: May 2017

Diplodocids are among the best known sauropod dinosaurs. Numerous specimens of currently 15 accepted species belonging to ten genera have been reported from the Late Jurassic to Early Cretaceous of North and South America, Europe, and Africa. The highest diversity is known from the Upper Jurassic Morrison Formation of the western United States: a recent review recognized 12 valid, named species, and possibly three additional, yet unnamed ones. One of these is herein described in detail and referred to the genusGaleamopus. The holotype specimen ofGaleamopus pabstisp. nov., SMA 0011, is represented by material from all body parts but the tail, and was found at the Howe-Scott Quarry in the northern Bighorn Basin in Wyoming, USA. Autapomorphic features of the new species include a horizontal canal on the maxilla that connects the posterior margin of the preantorbital and the ventral margin of the antorbital fenestrae, a vertical midline groove marking the sagittal nuchal crest, the presence of a large foramen connecting the postzygapophyseal centrodiapophyseal fossa and the spinopostzygapophyseal fossa of mid- and posterior cervical vertebrae, a very robust humerus, a laterally placed, rugose tubercle on the concave proximal portion of the anterior surface of the humerus, a relatively stout radius, the absence of a distinct ambiens process on the pubis, and a distinctly concave posteroventral margin of the ascending process of the astragalus. In addition to the holotype specimen SMA 0011, the skull USNM 2673 can also be referred toGaleamopus pabsti. Histology shows that the type specimen SMA 0011 is sexually mature, although neurocentral closure was not completed at the time of death. Because SMA 0011 has highly pneumatized cervical vertebrae, the development of the lamination appears a more important indicator for individual age than neurocentral fusion patterns. SMA 0011 is one of very few sauropod specimens that preserves the cervico-dorsal transition in both vertebrae and ribs. The association of ribs with their respective vertebrae shows that the transition between cervical and dorsal vertebrae is significantly different inGaleamopus pabstithan inDiplodocus carnegiiorApatosaurus louisae, being represented by a considerable shortening of the centra from the last cervical to the first dorsal vertebra. Diplodocids show a surprisingly high diversity in the Morrison Formation. This can possibly be explained by a combination of geographical and temporal segregation, and niche partitioning.
The earliest known titanosauriform sauropod dinosaur and the evolution of Brachiosauridae
Authors: Mannion Philip D. , Allain Ronan , Moine Olivier
Published: May 2017

Brachiosauridae is a clade of titanosauriform sauropod dinosaurs that includes the well-known Late Jurassic taxaBrachiosaurusandGiraffatitan. However, there is disagreement over the brachiosaurid affinities of most other taxa, and little consensus regarding the clade’s composition or inter-relationships. An unnamed partial sauropod skeleton was collected from middle–late Oxfordian (early Late Jurassic) deposits in Damparis, in the Jura department of eastern France, in 1934. Since its brief description in 1943, this specimen has been informally known in the literature as the ‘Damparis sauropod’ and ‘FrenchBothriospondylus’, and has been considered a brachiosaurid by most authors. If correctly identified, this would make the specimen the earliest known titanosauriform. Coupled with its relatively complete nature and the rarity of Oxfordian sauropod remains in general, this is an important specimen for understanding the early evolution of Titanosauriformes. Full preparation and description of this specimen, known from teeth, vertebrae and most of the appendicular skeleton of a single individual, recognises it as a distinct taxon:Vouivria damparisensisgen. et sp. nov. Phylogenetic analysis of a data matrix comprising 77 taxa (including all putative brachiosaurids) scored for 416 characters recovers a fairly well resolved Brachiosauridae.Vouivriais a basal brachiosaurid, confirming its status as the stratigraphically oldest known titanosauriform. Brachiosauridae consists of a paraphyletic array of Late Jurassic forms, withEuropasaurus,VouivriaandBrachiosaurusrecovered as successively more nested genera that lie outside of a clade comprising (Giraffatitan+Sonorasaurus) + (Lusotitan+ (Cedarosaurus+Venenosaurus)).Abydosaurusforms an unresolved polytomy with the latter five taxa. The Early Cretaceous South American sauropodPadillasauruswas previously regarded as a brachiosaurid, but is here placed within Somphospondyli. A recent study contended that a number of characters used in a previous iteration of this data matrix are ‘biologically related’, and thus should be excluded from phylogenetic analysis. We demonstrate that almost all of these characters show variation between taxa, and implementation of sensitivity analyses, in which these characters are excluded, has no effect on tree topology or resolution. We argue that where there is morphological variation, this should be captured, rather than ignored. Unambiguous brachiosaurid remains are known only from the USA, western Europe and Africa, and the clade spanned the Late Jurassic through to the late Albian/early Cenomanian, with the last known occurrences all from the USA. Regardless of whether their absence from the Cretaceous of Europe, as well as other regions entirely, reflects regional extinctions and genuine absences, or sampling artefacts, brachiosaurids appear to have become globally extinct by the earliest Late Cretaceous.
Analysis of microsatellites from the transcriptome of downy mildew pathogens and their application for characterization ofPseudoperonosporapopulations
Authors: Wallace Emma C. , Quesada-Ocampo Lina M.
Published: May 2017

Downy mildew pathogens affect several economically important crops worldwide but, due to their obligate nature, few genetic resources are available for genomic and population analyses. Draft genomes for emergent downy mildew pathogens such as the oomycetePseudoperonospora cubensis, causal agent of cucurbit downy mildew, have been published and can be used to perform comparative genomic analysis and develop tools such as microsatellites to characterize pathogen population structure. We used bioinformatics to identify 2,738 microsatellites in theP. cubensispredicted transcriptome and evaluate them for transferability to the hop downy mildew pathogen,Pseudoperonospora humuli, since no draft genome is available for this species. We also compared the microsatellite repertoire ofP. cubensisto that of the model organismHyaloperonospora arabidopsidis, which causes downy mildew in Arabidopsis. Although trends in frequency of motif-type were similar, the percentage of SSRs identified fromP. cubensistranscripts differed significantly fromH. arabidopsidis. The majority of a subset of microsatellites selected for laboratory validation (92%) produced a product inP. cubensisisolates, and 83 microsatellites demonstrated transferability toP. humuli. Eleven microsatellites were found to be polymorphic and consistently amplified inP. cubensisisolates. Analysis ofPseudoperonosporaisolates from diverse hosts and locations revealed higher diversity inP. cubensiscompared toP. humuliisolates. These microsatellites will be useful in efforts to better understand relationships withinPseudoperonosporaspecies andP. cubensison a population level.
Expansión de la oferta y matrícula de Programas de Magíster en universidades chilenas: una mirada desde las políticas de aseguramiento de la calidad
Authors:   Agencia Acreditadora de la Calidad en Educación Superior QUALITAS, Aravena Rodríguez María Teresa , Meza Sánchez Alexis ,   Agencia Acreditadora de la Calidad en Educación Superior QUALITAS
Published: May 2017

La oferta y matrícula de programas de magíster ha tenido un crecimiento significativo en los últimos años. Este crecimiento se ha concentrado preferentemente en algunas áreas de conocimiento y en universidades privadas creadas con posterioridad a 1981. El problema de ello radica en que las áreas e instituciones donde se ha concentrado el proceso de expansión de la oferta y matricula constituyen el sector de menor participación en materia de acreditación de programas. Por un lado, estas universidades no se acreditan en el área de Docencia de Postgrado, mientras que, por otro lado, los programas de magíster en estas áreas exhiben un bajo nivel de participación en procesos de acreditación. Lo anterior nos demuestra la importancia que ha ido adquiriendo la formación de magíster, en términos de oferta de programas y estudiantes matriculados, lo que transforma a este sector en un objeto de estudio de interés.
La construcción del modelo de proceso de selección de un programa de posgrado
Authors:   Universidad Autónoma de Yucatán, Facultad de Educación, Mérida Yucatán México, Martín Pavón Mario José , Sevilla Santo Dora Esperanza ,   Universidad Autónoma de Yucatán, Facultad de Educación, Mérida Yucatán México, Beltrán Poot Augusto David ,   Universidad Autónoma de Yucatán, Facultad de Educación, Mérida Yucatán México
Published: May 2017

Los programas de posgrado en México presentan altos índices de deserción y rezago. Este problema ha llevado a las IES y los organismos evaluadores a implementar estrategias, buscando garantizar la calidad de los programas y que los aspirantes que ingresen a éstos concluyan en tiempo y forma el plan de estudios. En este contexto, el objetivo de esta investigación es identificar los factores personales y sociales que predicen el rendimiento académico de los estudiantes de la Maestría en Investigación Educativa (programa ofertado por una universidad pública del sureste de México), de manera que estos se utilicen en la construcción de un modelo de proceso de selección que garantice el ingreso de los estudiantes más aptos para satisfacer las demandas de dicho programa. El estudio se desarrolló bajo el paradigma cuantitativo y es de alcance correlacional. Se trabajó con egresados de las cohortes 2004-2014. Los resultados señalan que los hábitos de estudio y las experiencias en investigación son factores que condicionan el rendimiento académico, por lo que deben ser considerados como indicadores de desempeño en el proceso de ingreso, junto con otros aspectos que se proponen dada la importancia de la información que refieren.
The effects of inhomogeneous proton‐α drifts on the heating of the solar wind
Authors: Ofman L. , Viñas A. F. , Roberts D. A.
Published: May 2017

Previous modeling studies have demonstrated that waves and super‐Alfvénic drift can lead to perpendicular preferential heating of the α particles with respect to protons. Using 2.5‐D hybrid model of the solar wind α‐proton plasma, we study the effects of inhomogeneous (across the magnetic field) background streaming focusing on the fast solar wind. We explore the effects of an initial relative, inhomogeneous ion drift on the perpendicular ion heating and cooling and consider the effects of solar wind expansion. We study the spectrum of the magnetic fluctuations in the inhomogeneous background solar wind and demonstrate the generation of oblique waves and their effects on enhanced resonant anisotropic ion heating. The model reproduces the typical ion temperature anisotropy values seen in observations. Using our model, we find that inhomogeneous super‐Alfvénic ion drift in the plasma generates significant power of oblique waves in the solar wind plasma, in addition to enhanced heating compared to the nondrifting populations. We demonstrate the effects of various inhomogeneity profiles and regions of the drift on the ion anisotropic heating in super‐Alfvénic and near‐Alfvénic drifts. We find that the cooling effect due to the solar wind expansion is not significant when super‐Alfvénic drifts are considered.
Magnetic fabric (anisotropy of magnetic susceptibility) constraints on emplacement mechanism of clastic dikes
Authors: Cho Hyeongseong , Son Moon , Sohn Young Kwan , Park Mi Eun
Published: May 2017

Clastic dikes are generally classified into neptunian and injected dikes. Using the magnetic fabrics (AMS: anisotropy of magnetic susceptibility), we attempt to classify the clastic dikes in the Late Cretaceous Dadaepo Basin, SE Korea, and interpret their emplacement mechanisms. The neptunian dikes exhibit a typical oblate sedimentary fabric which makes a sharp contrast with the injected dikes. The fabrics of the injected dikes are greatly influenced by current conditions and transportation types of filling materials. Based on the AMS fabrics, they are classified into four types. (1) VP (vertical flow‐parallel) type is formed by imbrication of long axis of grains in low‐ to moderate‐energy vertical flow of a Newtonian fluid and characterized by a bilateral symmetry of fabrics across the dike. (2) VT (vertical flow‐transverse fabric) type results from grain rolling in vertical high‐energy flow and is characterized by subvertical k2 and subhorizontal k1 axes on the dike plane. (3) HP (horizontal flow‐parallel) type is formed by imbrication of long axis of grains in horizontal low‐ to moderate‐energy flow, resulting in subvertical k3 and subhorizontal k1 and k2 axes. (4) HT (horizontal flow‐transverse) type is formed by grain rolling in horizontal high‐energy flow, resulting in streaked k2‐k3 on the dike plane and horizontally clustered k1 axes. The AMS fabrics of each type can be a significant indicator for flow direction. Based on abundant AMS fabrics formed by high‐energy current, coexistence of paleoseismic structures, and tectonic setting of the basin, earthquake‐induced liquefaction is the most plausible trigger for the dike formation.
Intercomparison of the gold, platinum, and MgO pressure scales up to 140 GPa and 2500 K
Authors: Ye Y. , Prakapenka V. , Meng Y. , Shim S.‐H.
Published: May 2017

In order to intercalibrate the equations of state (EOSs) of the three widely used pressure standards, gold, platinum, and MgO, we have measured their unit cell volumes together in the laser‐heated diamond anvil cell up to 140 GPa and 2500 K. At 300 K, three standards agree with each other within ±2.5 GPa to 135 GPa if the EOSs measured in quasi‐hydrostatic media are used. We further refined the EOSs at 300 K, making them consistent with each other within ±1 GPa up to 135 GPa. At high temperature (T), the three standards match the best within ±1 GPa between 40 and 140 GPa, when we use the scales by Dorogokupets and Dewaele (2007). However, a 2–3 GPa discrepancy remains at 20–40 GPa and 1500–2000 K, with gold yielding the highest pressure (P). The pressure discrepancy is likely related to steep decreases in the Grüneisen parameter, the anharmonicity, and/or the electronic effects for the standards at the P‐T conditions. Because gold melts near the temperatures expected for the mantle transition zone, severe anharmonic effects expected under premelting conditions make gold unsuitable for determining the phase boundaries in the region. The pressure scales by Dorogokupets and Dewaele (2007) provide tighter constrains on the Clapeyron slopes of the postspinel boundary to −2.0 to −2.7 MPa/K and the postperovskite boundary to 7–10 MPa/K. The data and refined EOSs presented here allow for reliable comparisons among experiments with different pressure standards for the entire P‐T conditions expected for the Earth's lower mantle.
Vertical thermodynamic structure of the troposphere during the Norwegian young sea ICE expedition (N‐ICE2015)
Authors: Kayser Markus , Maturilli Marion , Graham Robert M. , Hudson Stephen R. , Rinke Annette , Cohen Lana , Kim Joo‐Hong , Park Sang‐Jong , Moon Woosok , Granskog Mats A.
Published: May 2017

The Norwegian young sea ICE (N‐ICE2015) expedition was designed to investigate the atmosphere‐snow‐ice‐ocean interactions in the young and thin sea ice regime north of Svalbard. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N‐ICE2015 with respect to changes in the vertical thermodynamic structure, moisture content, and boundary layer characteristics. We provide statistics of temperature inversion characteristics, static stability, and boundary layer extent. During winter, when radiative cooling is most effective, we find the strongest impact of synoptic cyclones. Changes to thermodynamic characteristics of the boundary layer are associated with transitions between the radiatively “clear” and “opaque” atmospheric states. In spring, radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. Further, we compare the N‐ICE2015 static stability distributions to corresponding profiles from ERA‐Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny‐Ålesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N‐ICE2015 and SHEBA throughout the troposphere, despite differences in location, sea ice thickness, and snow cover. For Ny‐Ålesund, we observe similar characteristics above 1000 m, while the topography and ice‐free fjord surrounding Ny‐Ålesund generate great differences below. The long‐term radiosonde record (1993–2014) from Ny‐Ålesund indicates that during the N‐ICE2015 spring period, temperatures were close to the climatological mean, while the lowest 3000 m were 1–3°C warmer than the climatology during winter.
Atmospheric rivers in 20 year weather and climate simulations: A multimodel, global evaluation
Authors: Guan Bin , Waliser Duane E.
Published: May 2017

Atmospheric rivers (ARs) are narrow, elongated, synoptic jets of water vapor that play important roles in the global water cycle and meteorological/hydrological extremes. Increasing evidence shows that ARs have signatures and impacts in many regions across different continents. However, global‐scale characterizations of AR representations in weather and climate models have been very limited. Using a recently developed AR detection algorithm oriented for global applications, the representation of AR activities in multidecade weather/climate simulations is evaluated. The algorithm is applied to 6‐hourly (daily) integrated water vapor transport (IVT) from 22 (2) global weather/climate models that participated in the Global Energy and Water Cycle Experiment Atmospheric System Study–Year of Tropical Convection Multimodel Experiment, including four models with ocean‐atmosphere coupling and two models with superparameterization. Multiple reanalysis products are used as references to help quantify model errors in the context of reanalysis uncertainty. Model performance is examined for key aspects of ARs (frequency, intensity, geometry, and seasonality), with the focus on identifying and understanding systematic errors in simulated ARs. The results highlight the range of model performances relative to reanalysis uncertainty in representing the most basic features of ARs. Among the 17 metrics considered, AR frequency, zonal IVT, fractional zonal circumference, fractional total meridional IVT, and three seasonality metrics have consistently large errors across all models. Possible connections between AR simulation qualities and aspects of model configurations are discussed. Despite the lack of a monotonic relationship, the importance of model horizontal resolution to the overall quality of AR simulation is suggested by the evaluation results.
First reprocessing of Southern Hemisphere ADditional OZonesondes (SHADOZ) profile records (1998–2015): 1. Methodology and evaluation
Authors: Witte Jacquelyn C. , Thompson Anne M. , Smit Herman G. J. , Fujiwara Masatomo , Posny Françoise , Coetzee Gert J. R. , Northam Edward T. , Johnson Bryan J. , Sterling Chance W. , Mohamad Maznorizan , Ogino Shin‐Ya , Jordan Allen , da Silva Francisco R.
Published: May 2017

Electrochemical concentration cell ozonesonde measurements are an important source of highly resolved vertical profiles of ozone (O3) with long‐term data records for deriving O3trends, model development, satellite validation, and air quality studies. Ozonesonde stations employ a range of operational and data processing procedures, metadata reporting, and instrument changes that have resulted in inhomogeneities within individual station data records. A major milestone is the first reprocessing of seven Southern Hemisphere ADditional OZonesondes (SHADOZ) station ozonesonde records to account for errors and biases in operating/processing procedures. Ascension Island, Hanoi, Irene, Kuala Lumpur, La Réunion, Natal, and Watukosek station records all show an overall increase in O3after reprocessing. Watukosek shows the largest increase of 9.0 ± 2.1 Dobson Units (DU) in total column O3; Irene and Hanoi show a 5.5 ± 2.5 DU increase, while remaining sites show statistically insignificant enhancements. Negligible to modest O3enhancements are observed after reprocessing in the troposphere (up to 8%) and stratosphere (up to 6%), except at La Réunion for which the application of background currents reduces tropospheric O3(−2.1 ± 1.3 DU). Inhomogeneities due to ozonesonde/solution‐type changes at Ascension, Natal, and La Réunion are resolved with the application of transfer functions. Comparisons with EP‐TOMS, Aura's Ozone Monitoring Instrument and Microwave Limb Sounder (MLS) satellite O3overpasses show an overall improvement in agreement after reprocessing. Most reprocessed data sets show a significant reduction in biases with MLS at the ozone maximum region (50–10 hPa). Changes in radiosonde/ozonesonde system and nonstandard solution types can account for remaining discrepancies observed at several sites when compared to satellites.
Role of stationary and transient waves in CO2 supersaturation during northern winter in the Martian atmosphere revealed by MGS radio occultation measurements
Authors: Noguchi K. , Morii Y. , Oda N. , Kuroda T. , Tellmann S. , Pätzold M.
Published: May 2017

The Martian atmosphere, which mainly consists of carbon dioxide (CO2), is characterized by extremely low temperatures that cause CO2 gas to freeze and dry ice to form. To date, temperatures below the CO2 saturation temperature, which can be attributed to the effects of atmospheric waves, have been observed in the polar winter and in the mesosphere. Using data from Mars Global Surveyor (MGS) radio occultation measurements, we investigated the role of large‐scale atmospheric waves including stationary and transient waves at northern high latitudes in winter on CO2 supersaturation. A distinct longitudinal dependence of CO2 supersaturation was observed at altitudes higher than the pressure level of 200–400 Pa, where a stationary wave with a wave number of 2, whose temperature amplitude had minima at 30–100 Pa, lowered the background temperature to a level close to the CO2 saturation temperature. However, the stationary wave alone was not sufficient to cause CO2 supersaturation. Additional temperature disturbances caused by transient waves, namely, superposition of both waves, had a significant role in CO2 supersaturation. The longitudinal dependence of the occurrence of CO2 supersaturation revealed by our study might affect the longitudinal distribution of CO2 snowfall and the formation of the seasonal polar ice cap.
Amazonian fluvial outflow channels in Jovis Tholus region, Mars
Authors: Vijayan S. , Sinha Rishitosh K.
Published: May 2017

Outflow channels are prevalent on the surface of Mars, and they are one of the strongest lines of evidence for fluvial activity. The purported presence of some of the channel networks on the Amazonian surface provides evidence for recent surficial fluvial activity. We describe morphological evidence collectively diagnostic of fluvial origin for the channels located northwest (NW) of Jovis Tholus, within the Tharsis volcanic province. The fluvial relationships are deciphered from (1) morphological analysis of catastrophic effusion associated with the graben system superposed over the NW portion of an unnamed crater ejecta (19.85°N, 118.03°W) and (2) crater‐size frequency distributions of unnamed crater ejecta revealing the tentative period of the fluvial activity. Channels, streamlined/curvilinear islands, terraces, divide crossing, crossover channels, networks of braided‐like channels, and eroded ejecta are collectively suggestive of fluvial outflow that emanated from the graben. Chronological analysis revealed that the unnamed crater formed at ~3.4 Ga. Subsequently, the NW part of crater ejecta was incised by a channel network originated from the graben. Furthermore, we infer that the current channel floor has undergone volcanic and aeolian resurfacing to some extent, and the estimated modeled resurfaced channel age is ~0.2–0.5 Ga. This reveals that the fluvial activity possibly occurred after the crater formation, but before channel floor resurfacing, which is during Early to Middle Amazonian. Nevertheless, the potential source for the channel formation likely persisted under this region since the pre‐Amazonian epoch. The suite of these fluvial features inferred within the Jovis Tholus region outflow channel system thus adds one another evidence for Amazonian fluvial activity.
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing
Authors: Ashmore David W. , Hubbard Bryn , Luckman Adrian , Kulessa Bernd , Bevan Suzanne , Booth Adam , Munneke Peter Kuipers , O'Leary Martin , Sevestre Heidi , Holland Paul R.
Published: May 2017

We use borehole optical televiewing (OPTV) to explore the internal structure of Larsen C Ice Shelf (LCIS). We report a suite of five ~90 m long OPTV logs, recording a light‐emitting diode‐illuminated, geometrically correct image of the borehole wall, from the northern and central sectors of LCIS collected during austral spring 2014 and 2015. We use a thresholding‐based technique to estimate the refrozen ice content of the ice column and exploit a recently calibrated density‐luminosity relationship to reveal its structure. All sites are dense and strongly influenced by surface melt, with frequent refrozen ice layers and mean densities, between the depths of 1.87 and 90 m, ranging from 862 to 894 kg m−3. We define four distinct units that comprise LCIS and relate these to ice provenance, dynamic history, and past melt events. These units are in situ meteoric ice with infiltration ice (U1), meteoric ice which has undergone enhanced densification (U2), thick refrozen ice (U3), and advected continental ice (U4). We show that the OPTV‐derived pattern of firn air content is consistent with previous estimates, but that a significant proportion of firn air is contained within U4, which we interpret to have been deposited inland of the grounding line. The structure of LCIS is strongly influenced by the E‐W gradient in föhn‐driven melting, with sites close to the Antarctic Peninsula being predominantly composed of refrozen ice. Melting is also substantial toward the ice shelf center with >40% of the overall imaged ice column being composed of refrozen ice.
Characteristics of high‐latitude precursor flows ahead of dipolarization fronts
Authors: Li Jia‐Zheng , Zhou Xu‐Zhi , Runov Andrei , Angelopoulos Vassilis , Liu Jiang , Pan Dong‐Xiao , Zong Qiu‐Gang
Published: May 2017

Dipolarization fronts (DFs), earthward propagating structures in the magnetotail current sheet characterized by sharp enhancements of northward magnetic field, are capable of converting electromagnetic energy into particle kinetic energy. The ions previously accelerated and reflected at the DFs can contribute to plasma flows ahead of the fronts, which have been identified as DF precursor flows in both the near‐equatorial plasma sheet and far from it, near the plasma sheet boundary. Using observations from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft, we show that the earthward particle and energy flux enhancements ahead of DFs are statistically larger farther away from the neutral sheet (at high latitudes) than in the near‐equatorial region. High‐latitude particle and energy fluxes on the DF dawnside are found to be significantly greater than those on the duskside, which is opposite to the dawn‐dusk asymmetries previously found near the equatorial region. Using forward and backward tracing test‐particle simulations, we then explain and reproduce the observed latitude‐dependent characteristics of DF precursor flows, providing a better understanding of ion dynamics associated with dipolarization fronts.
Source of the 1730 Chilean earthquake from historical records: Implications for the future tsunami hazard on the coast of Metropolitan Chile
Authors: Carvajal M. , Cisternas M. , Catalán P. A.
Published: May 2017

Historical records of an earthquake that occurred in 1730 affecting Metropolitan Chile provide essential clues on the source characteristics for the future earthquakes in the region. The earthquake and tsunami of 1730 have been recognized as the largest to occur in Metropolitan Chile since the beginning of written history. The earthquake destroyed buildings along >1000 km of the coast and produced a large tsunami that caused damage as far as Japan. Here its source characteristics are inferred by comparing local tsunami inundations computed from hypothetical earthquakes with varying magnitude and depth, with those inferred from historical observations. It is found that a 600–800 km long rupture involving average slip amounts of 10–14 m (Mw 9.1–9.3) best explains the observed tsunami heights and inundations. This large earthquake magnitude is supported by the 1730 tsunami heights inferred in Japan. The inundation results combined with local uplift reports suggest a southward increase of the slip depth along the rupture zone of the 1730 earthquake. While shallow slip on the area to the north of the 2010 earthquake rupture zone is required to explain the reported inundation, only deeper slip at this area can explain the coastal uplift reports. Since the later earthquakes of the region involved little or no slip at shallow depths, the near‐future earthquakes on Metropolitan Chile could release the shallow slip accumulated since 1730 and thus lead to strong tsunami excitation. Moderate shaking from a shallow earthquake could delay tsunami evacuation for the most populated coastal region of Chile.
Optical signatures of low spin Fe3+ in NAL at high pressure
Authors: Lobanov Sergey S. , Hsu Han , Lin Jung‐Fu , Yoshino Takashi , Goncharov Alexander F.
Published: May 2017

The iron spin transition directly affects properties of lower mantle minerals and can thus alter geophysical and geochemical characteristics of the deep Earth. While the spin transition in ferropericlase has been documented at P ~60 GPa and 300 K, experimental evidence for spin transitions in other rock‐forming minerals, such as bridgmanite and post‐perovskite, remains controversial. Multiple valence, spin, and coordination states of iron in bridgmanite and post‐perovskite are difficult to resolve with conventional spin probing techniques. Optical spectroscopy, on the other hand, can discriminate between high and low spin and between ferrous and ferric iron at different sites. Here we establish the optical signature of low spin Fe3+O6, a plausible low spin unit in bridgmanite and post‐perovskite, by optical absorption experiments in diamond anvil cells. We show that the optical absorption of Fe3+O6 in new aluminous phase (NAL) is very sensitive to the iron spin state and may represent a model behavior of bridgmanite and post‐perovskite across the spin transition. Specifically, an absorption band centered at ~19,000 cm−1 is characteristic of the 2T2g → 2T1g (2A2g) transition in low spin Fe3+ in NAL at 40 GPa, constraining the crystal field splitting energy of low spin Fe3+ to ~22,200 cm−1, which we independently confirm by first‐principles calculations. Together with available information on the electronic structure of Fe3+O6 compounds, we show that the spin‐pairing energy of Fe3+ in an octahedral field is ~20,000–23,000 cm−1. This implies that octahedrally coordinated Fe3+ in bridgmanite is low spin at P > ~40 GPa.
Seasonal variability of the hydrogen exosphere of Mars
Authors: Halekas J. S.
Published: May 2017

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures both the upstream solar wind and collisional products from energetic neutral hydrogen atoms that precipitate into the upper atmosphere after their initial formation by charge exchange with exospheric hydrogen. By computing the ratio between the densities of these populations, we derive a robust measurement of the column density of exospheric hydrogen upstream of the Martian bow shock. By comparing with Chamberlain‐type model exospheres, we place new constraints on the structure and escape rates of exospheric hydrogen, derived from observations sensitive to a different and potentially complementary column from most scattered sunlight observations. Our observations provide quantitative estimates of the hydrogen exosphere with nearly complete temporal coverage, revealing order of magnitude seasonal changes in column density and a peak slightly after perihelion, approximately at southern summer solstice. The timing of this peak suggests either a lag in the response of the Martian atmosphere to solar inputs or a seasonal effect driven by lower atmosphere dynamics. The high degree of seasonal variability implied by our observations suggests that the Martian atmosphere and the thermal escape of light elements depend sensitively on solar inputs.
Smoking Behavior Changes in the Early Rheumatoid Arthritis Period and Risk of Mortality During Thirty‐Six Years of Prospective Followup
Authors: Sparks Jeffrey A. , Chang Shun‐Chiao , Nguyen Uyen‐Sa D. T. , Barbhaiya Medha , Tedeschi Sara K. , Lu Bing , Costenbader Karen H. , Zhang Yuqing , Choi Hyon K. , Karlson Elizabeth W.
Published: May 2017

Objective

To investigate whether rheumatoid arthritis (RA) diagnosis influences smoking behavior changes and whether these changes were associated with mortality.

Methods

We identified an incident RA cohort in the Nurses' Health Study (NHS; 1976–2012). Behavioral data were collected through biennial questionnaires. We created a comparison cohort, matching RA cases to women without RA by age and calendar year at the index date of RA diagnosis. To investigate smoking behavior changes in the early RA period, sustained cessation was defined as permanently quitting within 4 years of the RA/index date. We used Cox regression to obtain hazard ratios (HRs) for mortality, comparing sustained smoking cessation to continued smoking.

Results

Among 121,700 women in the NHS, we identified 938 with incident RA matched to 8,951 non‐RA comparators. Among current smokers, 40.0% with RA permanently quit smoking in the early RA period, compared to 36.1% of comparators (odds ratio for sustained cessation 1.18 [95% confidence interval (95% CI) 0.88, 1.58]). There were 313 deaths (33.4%) in the RA cohort and 2,042 (22.8%) among comparators. Compared to continued smoking, sustained cessation was associated with similarly decreased mortality in both the RA (HR 0.58 [95% CI 0.33, 1.01]) and comparison (HR 0.47 [95% CI 0.39, 0.58]) cohorts. Women with RA had higher mortality for >5 post‐RA pack‐years (HR 3.67 [95% CI 2.80, 4.81]) than comparators with >5 post‐index pack‐years (HR 1.88 [95% CI 1.62, 2.17]; P < 0.001 for interaction; reference: ever‐smoker non‐RA women with 0 post‐index pack‐years).

Conclusion

Sustained smoking cessation within 4 years of RA diagnosis reduced mortality risk, with a similar effect observed among non‐RA comparators. Smoking >5 pack‐years after RA diagnosis significantly increased mortality beyond the risk of non‐RA comparators.
Prescribing for Children With Rheumatic Disease: Perceived Treatment Approaches Between Pediatric and Adult Rheumatologists
Authors: van Mater Heather , Balevic Stephen J. , Freed Gary L. , Clark Sarah J.
Published: May 2017

Objective

To compare practice patterns and prescribing differences for juvenile idiopathic arthritis (JIA) between adult rheumatologists (ARs) and pediatric rheumatologists (PRs), the perceived educational needs, and factors that enhance or impede co‐management.

Methods

Two parallel, cross‐sectional surveys focusing on JIA were administered in 2009 to a random sample of 193 PRs and 500 ARs using the American College of Rheumatology membership file. Bivariate analysis was conducted for common items.

Results

The response rate was 62.1% for ARs (n = 306) and 72.3% for PRs (n = 138). Only 23% of responding ARs (n = 69) reported caring for children with JIA. Of these, 94% strongly agreed/agreed feeling comfortable diagnosing JIA; however, only 76% felt comfortable treating JIA. Clinical vignettes highlighted several prescribing differences. Forty‐eight percent of ARs and 31% of PRs felt medications to treat JIA did not have clear dosing guidelines. Though PRs initiated disease‐modifying antirheumatic drugs and biologic agents earlier, treatments were similar after 3 months. To enhance co‐management, 74% of pediatric respondents endorsed shared medical records.

Conclusion

Nearly one‐quarter of surveyed ARs care for children with JIA, with most limiting their practice to older children. There was more discomfort in treating JIA than diagnosing it, and there were significant prescribing differences. Both provider types identified the need for better dosing and treatment resources. Updated management guidelines along with exposure to pediatric rheumatology in fellowship could reduce treatment differences and enhance the care of children with JIA. Shared medical records and improvement in reimbursement may optimize co‐management.
A Modular Antigen Presenting Peptide/Oligonucleotide Nanostructure Platform for Inducing Potent Immune Response
Authors: Tohumeken Sehmus , Gunduz Nuray , Demircan M. Burak , Gunay Gokhan , Topal Ahmet E. , Khalily M. Aref , Tekinay Turgay , Dana Aykutlu , Guler Mustafa O. , Tekinay Ayse B.
Published: May 2017

The design and development of vaccines, which can induce cellular immunity, particularly CD8+ T cells hold great importance since these cells play crucial roles against cancers and viral infections. Covalent conjugation of antigen and adjuvant molecules has been used for successful promotion of immunogenicity in subunit vaccines; however, the stimulation of the CD8+ T‐cell responses by this approach has so far been limited. This study demonstrates a modular system based on noncovalent attachment of biotinylated antigen to a hybrid nanofiber system consisting of biotinylated self‐assembling peptide and CpG oligodeoxynucleotides (ODN) molecules, via biotin–streptavidin interaction. These peptide/oligonucleotide hybrid nanosystems are capable of bypassing prior limitations related with inactivated or live‐attenuated virus vaccines and achieve exceptionally high CD8+ T‐cell responses. The nanostructures are found to trigger strong IgG response and effectively modulate cross‐presentation of their antigen “cargo” through close proximity between the antigen and peptide/ODN adjuvant system. In addition, the biotinylated peptide nanofiber system is able to enhance antigen uptake and induce the maturation of antigen‐presenting cells. Due to its versatility, biocompatibility, and biodegradability with a broad variety of streptavidin‐linked antigens, the nanosystem shown here can be utilized as an efficient strategy for new vaccine development.
Is it Possible to Use Rolling Methods to Improve Textures on Fe–Mn–Si Shape Memory Alloys?
Authors: Druker Ana V. , Sobrero César , Fuster Valeria , Malarría Jorge , Bolmaro Raúl
Published: May 2017

No uniform rolling deformation produces shear strains that give rise to textural and microstructural heterogeneities in processed metals and alloys. In this work, the authors investigate Fe–30Mn–4Si shape memory alloy sheets rolled in different conditions at 600 °C, in order to determine the process giving rise to the best structure and the strongest {100}<110> shear texture. This crystallographic orientation is the most favorable for the γ → ϵ martensitic transformation, which provides the shape memory effect in these alloys. In the current conditions, the authors find that unidirectional rolling produces a shear texture in sheet's surface layers. The authors compare the texture and microstructure from this process to those obtained from reverse rolling and single‐roller drive rolling.
Thermally Induced Formation of Transition Aluminas from Boehmite
Authors: Rudolph Martin , Salomon Anton , Schmidt Anne , Motylenko Mykhaylo , Zienert Tilo , Stöcker Hartmut , Himcinschi Cameliu , Amirkhanyan Lilit , Kortus Jens , Aneziris Christos G. , Rafaja David
Published: May 2017

Structural changes occurring during the conversion of boehmite over the transient phases γ‐, δ‐ and θ‐Al2O3 to corundum were investigated. During the whole transition process, the specific surface area was reduced. The X‐ray and electron diffraction experiments revealed that the transition from γ‐ to θ‐Al2O3 is continuous and that it proceeds over different δ‐states rather than over a distinct δ‐Al2O3 phase. The reduction of the specific surface area was most pronounced prior to the onset of the phase transition from γ‐Al2O3 to the first δ‐state. In γ‐Al2O3, approximately 45% of Al cations were found to be located on tetrahedral sites within a slightly tetragonal distorted oxygen sublattice.
A Versatile Method to Fabricate Highly In‐Plane Aligned Conducting Polymer Films with Anisotropic Charge Transport and Thermoelectric Properties: The Key Role of Alkyl Side Chain Layers on the Doping Mechanism
Authors: Hamidi‐Sakr Amer , Biniek Laure , Bantignies Jean‐Louis , Maurin David , Herrmann Laurent , Leclerc Nicolas , Lévêque Patrick , Vijayakumar Vishnu , Zimmermann Nicolas , Brinkmann Martin
Published: May 2017

A general method is proposed to produce oriented and highly crystalline conducting polymer layers. It combines the controlled orientation/crystallization of polymer films by high‐temperature rubbing with a soft‐doping method based on spin‐coating a solution of dopants in an orthogonal solvent. Doping rubbed films of regioregular poly(3‐alkylthiophene)s and poly(2,5‐bis(3‐dodecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) yields highly oriented conducting polymer films that display polarized UV–visible–near‐infrared (NIR) absorption, anisotropy in charge transport, and thermoelectric properties. Transmission electron microscopy and polarized UV–vis–NIR spectroscopy help understand and clarify the structure of the films and the doping mechanism. F4TCNQ− anions are incorporated into the layers of side chains and orient with their long molecular axis perpendicular to the polymer chains. The ordering of dopant molecules depends closely on the length and packing of the alkyl side chains. Increasing the dopant concentration results in a continuous variation of unit cell parameters of the doped phase. The high orientation results in anisotropic charge conductivity (σ) and thermoelectric properties that are both enhanced in the direction of the polymer chains (σ = 22 ± 5 S cm−1 and S = 60 ± 2 µV K−1). The method of fabrication of such highly oriented conducting polymer films is versatile and is applicable to a large palette of semiconducting polymers.
A Charge Reversible Self‐Delivery Chimeric Peptide with Cell Membrane‐Targeting Properties for Enhanced Photodynamic Therapy
Authors: Liu Li‐Han , Qiu Wen‐Xiu , Zhang Yao‐Hui , Li Bin , Zhang Chi , Gao Fan , Zhang Lu , Zhang Xian‐Zheng
Published: May 2017

The cell membrane is the most important protective barrier in living cells and cell membrane targeted therapy may be a high‐performance therapeutic modality for tumor treatment. Here, a novel charge reversible self‐delivery chimeric peptide C16–PRP–DMA is developed for long‐term cell membrane targeted photodynamic therapy (PDT). The self‐assembled C16–PRP–DMA nanoparticles can effectively target to tumor by enhanced permeability and retention effect without additional carriers. After undergoing charge reverse in acidic tumor microenvironment, C16–PRP–DMA inserts into the tumor cell membrane with a long retention time of more than 14 h, which is very helpful for in vivo applications. It is found that under light irradiation, the reactive oxygen species generated by the inserted C16–PRP–DMA would directly disrupt cell membrane and rapidly induce cell necrosis, which remarkably increases the PDT effect in vitro and in vivo. This novel self‐delivery chimeric peptide with a long‐term cell membrane targeting property provides a new prospect for effective PDT of cancer.