bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological and phylogenetic aspects of the dentition of Megacephalosaurus eulerti, a pliosaurid from the Turonian of Kansas, USA, with remarks on the cranial anatomy of the taxon
Authors: MADZIA DANIEL , SACHS SVEN , LINDGREN JOHAN
Published: July 2018

Megacephalosaurus eulerti is a large macropredatory plesiosaur representing one of the last members of the diverse pliosaurid clade Brachaucheninae. The taxon was established upon a nearly complete skull including the mandible and fragments of the postcranial skeleton originating from the lower middle Turonian (Upper Cretaceous) of Kansas, USA. Owing to its age, reasonable completeness and its state of preservation, M. eulerti bears important anatomical details regarding the last brachauchenines. Here we assess the dentition of the taxon, compare the teeth to those of other thalassophonean pliosaurids and comment on the utility of these results for inferences of the phylogenetic relationships of the last brachauchenines. Additionally, we provide remarks on the cranial anatomy of M. eulerti, revise character scores of this taxon used in current phylogenetic studies and address the phylogenetic relationships within Brachaucheninae. Parsimony analyses, aimed to test different character sampling and tree-search strategy, inferred only a single unambiguous synapomorphy uniting a clade formed by mid- to Late Cretaceous brachauchenines: presence of subcircular rather than subtrihedral/trihedral cross-sectional shape of the teeth. Still, the last brachauchenines (Brachauchenius and Megacephalosaurus) can be roughly characterized by a switch from anisodont to subisodont dentition and reduction of their tooth count. Nevertheless, the overall knowledge of the origin, phylogenetic relationships and distinguishability of brachauchenine pliosaurids remains poor and represents a subject for further extensive studies and modifications in taxon and character sampling.
Communiqué: a planning-based sequence diagrams generator
Authors: Ahmed Moataz , Sulaiman Yaser
Published: July 2018

During the software system development lifecycle, different types of Unified Modeling Language model are developed to represent different views of the system. Sequence diagrams represent one of the most important types of model. They show how objects in the system interact to offer the functionality manifested in the form of use cases. As the complexity of the system being modeled increases, creating the sequence diagrams manually becomes harder. However, the problem of automatic sequence diagrams generation has not caught enough researchers yet. This paper presents an approach and a tool to automatically generate sequence diagrams from use cases and class diagrams. The problem of determining the sequence of message passing is treated as an Artificial Intelligence action planning problem and solved as such. In doing so, Design by Contract concepts are enforced in the specification of the given use cases and class diagrams. A special message-passing planner, Communiqué, was developed and implemented accordingly. The overall approach was empirically evaluated against sets of manually created sequence diagrams available in the literature. Communiqué was able to create sequence diagrams comparable to the manually developed ones. The paper also sheds the light on some directions for future work to advance the applicability of the approach.
STATISTICAL SENSITIVITY, COGNITIVE APTITUDES, AND PROCESSING OF COLLOCATIONS
Authors: Yi Wei
Published: July 2018

Frequency and contingency (i.e., co-occurrence probability of words in multiword sequences [MWS]) are two driving forces of language acquisition and processing. Previous research has demonstrated that L1 and advanced L2 speakers are sensitive to phrasal frequency and contingency when processing larger-than-word units. However, it remains unclear whether such statistical sensitivity is robust across tasks and among subcategories of MWS. In addition, little is known about whether cognitive aptitudes can moderate such sensitivity. This study examined L1 and advanced L2 speakers’ statistical sensitivity to phrasal frequency and contingency as well as cognitive aptitudes’ moderating effects on such sensitivity when processing English adjective-noun collocations. Participants performed a phrasal acceptability judgment task (PJT). Meanwhile, their aptitude profiles were measured by six aptitude tests, which loaded separately onto implicit language aptitude, explicit language aptitude, and working memory capacity. Linear mixed-effects modeling revealed that both L1 and L2 English speakers were sensitive to phrasal frequency and contingency of collocations, although L2 speakers’ sensitivity was much stronger than that of L1 speakers. None of the aptitudes was found to moderate language users’ statistical sensitivity to either collocation frequency or contingency. Interestingly, disassociation patterns between the PJT performance and the involvement of implicit or explicit language aptitude among the L1 and L2 speakers were found. It was concluded that L1 and L2 speakers differed in terms of the way they processed the collocations, as well as the nature of their collocational knowledge.
X-ray powder diffraction data for methoxmetamine hydrochloride, C14H20ClNO2
Authors: Jurasek Bronislav , Babor Martin , Huber Stepan , Kuchar Martin
Published: July 2018

X-ray powder diffraction data, unit-cell parameters and space group for methoxmetamine (C14H20ClNO2) are reported [a = 6.5768(7) Å, b = 14.0830(10) Å, c = 15.0530(10) Å, β = 90.975(2)°, unit-cell volume V = 1394.0(2) Å3, and Z = 4, and space group P21/n]. All measured lines were indexed and are consistent with the P21/n space group. No detectable impurities were observed.
The training of therapeutic radiographers in dementia care: a literature review
Authors: Carnall Chelsea , Chianese Janette
Published: July 2018

Background

In the United Kingdom, 7·1% of people aged over 65 live with dementia. The National Dementia Strategy emphasises the need for a skilled workforce competent in dementia care. In all, 50% of cancer patients are in the 70 plus age group, suggesting that education of therapeutic radiographers in the care of the patient with dementia is key. The aim of the study was to review the literature regarding training of therapeutic radiographers on dementia and use the findings to make recommendations for training in the future in order to provide the best care.

Materials and methods

A literature search of electronic databases holding peer-reviewed journals was conducted. Search terms were generated using the Population Intervention Comparison Outcome (PICO) method and retrieved articles were evaluated using the Critical Appraisal Skills Programme (CASP) tool. Additional evidence was accessed through snowballing and from grey literature.

Results

The search failed to find any studies on dementia care education within a radiotherapy setting and only a limited number were found in the acute care setting. There appeared to be a large variation in the education provision for healthcare professionals on the subject of dementia care, both at the pre-registration and post-registration stages.

Findings

There is no evidence of a standardised education programme for healthcare professionals in dementia care. In the future, therapeutic radiographers are likely to see more patients with dementia but currently some may not have had the education and training to provide effective holistic care.
How safe is radiotherapy practice in India: perceptions and practical experiences among the workers of radiotherapy facilities in North East, India?
Authors: Thokchom Singh Dewan
Published: July 2018

Purpose

The aim of this study was to understand how the regulatory requirements for functioning radiotherapy practices in India to control risk were conceptualised, perceived and applied accordingly in the radiotherapy facilities. It further examined how the social factors influenced the decision-making process for implementing regulatory requirements in the radiotherapy facilities.

Material and method

This study was carried out in nine radiotherapy facilities located in the northeastern Indian states of Manipur, Assam, Meghalaya, Tripura and Mizoram. The study adopted both the semi-structured and in-depth questionnaire, developed on the basis of multidisciplinary fields.

Result

The study found that the facilities in the northeastern regions were commissioned in line with the regulatory requirements. The facilities had adequate structural shielding rooms to protect workers, patients and the public from the risk of ionising radiation. However, in the operational phase of the facilities, majority of the facilities had the improper management of existing resources and non-implementation of regulatory requirements on time. It was observed that workers in some facilities continued the practice, despite the failure of specific safety functions, or not meeting regulatory requirements. Such practices led to the suspension of patient treatment in three of the facilities by the regulator. The existence of a varying nature of risk perceptions among oncologists, medical physicists, radiological safety officers, radiotherapy technologists in the facilities were observed and these influenced the decision-making process of the facilities on the implementation of regulatory requirements.

Conclusion

The study found that the facilities needed to explore various means, including to narrow the gap that existed in respects of perceived risk (within the facilities), communication to enhance work coordination and mutual trust among workers. The adoption of the institutional policy for conducting an internal audit of working practices, encouragement of workers to participate in continuing education programs would enhance effective utilisation of already existing infrastructure/equipment and work procedures including quality assurance programs.
Space Weather in the Heliosphere
Authors: Russell C. T.
Published: July 2018

We live on a very special planet in a very special solar system. Our planet has a benign climate. Our star has several habitable planets and is not so active as to inhibit the exploration and future colonization of these planets. In this short paper we review how the solar wind interacts with the planets, what factors matter in this interaction, and how active is our star.
Prediction of Ground Level Enhancements
Authors: Núñez Marlon , Reyes-Santiago Pedro J. , Malandraki Olga E.
Published: July 2018

This paper summarizes the first tool that is able to predict Ground Level Enhancements (GLE). It makes real-time predictions of the occurrence of GLE events from the analysis of soft X-ray and differential proton flux measured by the GOES satellite network. Before the development of this tool, space weather systems have been warning users about evolving GLE events by processing neutron measurements recorded on ground level. This tool, called HESPERIA UMASEP-500, can predict GLE events before the detection by any neutron monitor (NM) station. The prediction performance measured for the period from 1986 to 2016 is presented for two consecutive periods, because of their notable difference in performance. For the 2000-2016 period, this prediction tool obtained a probability of detection (POD) of 53.8% (7 of 13 GLE events), a false alarm ratio (FAR) of 30.0%, and average warning times (AWT) of 8 min and 15 min with respect to the first NM station’s alert and the GLE Alert Plus warning, respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under agreement No 637324.
Space Observations to Determine the Location of Locally Vertical Geomagnetic Field
Authors: Lepidi Stefania , Di Mauro Domenico , Tozzi Roberta , Cafarella Lili , De Michelis Paola , Marzocchetti Martina
Published: July 2018

The points where the horizontal component of the geomagnetic field vanishes are located in polar areas, far away from the geomagnetic (analytic) poles and the poles of rotation of the Earth and, differently from the geomagnetic poles, can be found experimentally with a magnetic survey to determine where the field is vertical. The experimental determination of the area where the total field is perfectly vertical, commonly known as dip pole, is not simple, due to the remoteness and harsh climatic conditions; another difficulty is related to the short term geomagnetic field variations, due to the interaction with the external solar wind, which causes the magnetospheric dynamics, particularly evident at high latitude, and as a consequence a displacement of the dip pole. Actually, the study of the dip pole displacements over short time scales can be an important tool for monitoring the magnetospheric dynamics at high latitude. In this study we present the updated location of the the dip poles, using data from the Swarm ESA’s constellation of satellites along their almost polar orbits. We also analyse the spatial shift of these areas during different seasons and interplanetary magnetic field orientations.
Solar Radio Emission as a Prediction Technique for Coronal Mass Ejections’ Detection
Authors: Fridman Vladimir M. , Sheiner Olga A.
Published: July 2018

In this report we present a possible scheme of short-term CME detection forecasting developed on the basis of statistical analysis of solar radio emission regularities prior to “isolated” solar Coronal Mass Ejections registered in 1998, 2003, 2009-2013.
The Belgian Space Weather Observatory in Dourbes
Authors: Sapundjiev D. , Verhulst T. G. W. , Stankov S. M. , Jodogne J. C.
Published: July 2018

The paper outlines the space-weather-related observations, instrumentation, research and service developments carried out at the Geophysical Centre of the Royal Meteorological Institute (RMI) in Dourbes, Belgium.
Electron Acceleration in Collapsing Magnetic Traps during the Solar Flare on July 19, 2012: Observations and Models
Authors: Gritsyk P. A. , Somov B. V.
Published: July 2018

Using the appropriate kinetic equation, we considered the problem of propagation of accelerated electrons into the solar corona and chromosphere. Its analytical solution was used for modelling the M7.7 class limb flare occurred on July 19, 2012. Coronal above-the-loop-top hard X-Ray source was interpreted in the thin-target approximation, the foot-point source - in the thick-target approximation with account of the reverse-current electric field. For the foot-point source we found a good accordance with the RHESSI observations. For the coronal source we also got very accurate estimate of the power-law spectral index, but significant differences between the modelled and observed hard X-ray intensities were noticed. The last discrepancy was solved by adding the coronal magnetic trap model to the thin target model. The former one implies that the trap collapses in two dimensions, locks and accelerates particles inside itself. In our report, we confirm an existence and high efficiency of the electron acceleration in collapsing magnetic traps during solar flares. Our new results represent (e.g. for RHESSI observations) the theoretical prediction of the double step particle acceleration in solar flares, when the first step is the acceleration in reconnection area and the second one – the acceleration in coronal trap.
Forecasting Solar Energetic Particle Fluence with Multi-Spacecraft Observations
Authors: Laitinen T. , Dalla S. , Battarbee M. , Marsh M. S.
Published: July 2018

Forecasting Solar Energetic Particle (SEP) fluence, as integrated over an SEP event, is an important element when estimating the effect of solar eruptions on humans and technology in space. Current real-time estimates are based on SEP measurements at a single location in space. However, the interplanetary magnetic field corotates with the Sun approximately 13° each day with respect to Earth, thus in 4 days a near-Earth spacecraft will have changed their connection about 60° from the original SEP source. We estimate the effect of the corotation on particle fluence using a simple particle transport model, and show that ignoring corotation can cause up to an order of magnitude error in fluence estimations, depending on the interplanetary particle transport conditions. We compare the model predictions with STEREO observations of SEP events.
Geomagnetic Consequences of Interacting CMEs of June 13-14, 2012
Authors: Srivastava Nandita , Mirtoshev Zavkiddin , Mishra Wageesh
Published: July 2018

We have studied the consequences of interacting coronal mass ejections (CMEs) of June 13-14, 2012 which were directed towards Earth and caused a moderate geomagnetic storm with Dst index ~ −86 nT. We analysed the in-situ observations of the solar wind plasma and magnetic field parameters obtained from the OMNI database for these CMEs. The in-situ observations show that the interacting CMEs arrive at Earth with the strongest (~ 150 nT) Sudden Storm Commencement (SSC) of the solar cycle 24. We compared these interacting CMEs to a similar interaction event which occurred during November 9-10, 2012. This occurred in the same phase of the solar cycle 24 but resulted in an intense geomagnetic storm (Dst ~ −108 nT), as reported by Mishra et al. (2015). Our analysis shows that in the June event, the interaction led to a merged structure at 1 AU while in the case of November 2012 event, the interacted CMEs arrived as two distinct structures at 1 AU. The geomagnetic signatures of the two cases reveal that both resulted in a single step geomagnetic storm.
The Response of the Martian Atmosphere to Space Weather
Authors: Brain David A.
Published: July 2018

Mars lacks a global dynamo magnetic field to shield it from the solar wind and solar storms, so may be especially sensitive to changing space weather compared to Earth. Inputs from the Sun and solar wind have been measured continuously at Mars for 20 years, and intermittently for more than 50 years. Observations of the influence of the variable space weather at Mars include compression and reconfiguration of the magnetosphere in response to solar storms, increased likelihood of aurora and increased auroral electron energies, increased particle precipitation and ionospheric densities during flare and energetic particle events, and increased ion escape during coronal mass ejection events. Continuing measurements at Mars provide a useful vantage point for studying space weather propagation into the heliosphere, and are providing insight into the evolution of the Martian atmosphere and the role that planetary magnetic fields play in helping planets to retain habitable conditions near their surface.
Statistical Analysis of Extreme Electron Fluxes in the Radiation Belts
Authors: Lanabere Vanina , Dasso Sergio
Published: July 2018

The main aim of this work is to study the frequency of extreme Space Weather events, in particular to analyse the tails of the daily averaged electron fluxes distribution function for different channels of energy between 0.249–1.192 MeV measured at ~ 600 km of altitude with the particle detector ICARE-NG/CARMEN-1 on board argentinian polar satellite SAC-D. An extreme value theory was applied to estimate the maximum values of the electron flux in the outer radiation belt for different return levels. We found that the cumulative distribution function of the extreme electron fluxes presents a finite upper limit in (1) the core of the outer radiation belt for the lower energy channels and (2) in the inner edge of the outer radiation belt for energy channels larger than 0.653 keV. The results presented in this work are important to characterise Space Weather conditions.
Application of Test Particle Simulations to Solar Energetic Particle Forecasting
Authors: Dalla S. , Swalwell B. , Battarbee M. , Marsh M. S. , Laitinen T. , Proctor S. J.
Published: July 2018

Modelling of Solar Energetic Particles (SEPs) is usually carried out by means of the 1D focused transport equation and the same approach is adopted within several SEP Space Weather forecasting frameworks. We present an alternative approach, based on test particle simulations, which naturally describes 3D particle propagation. The SPARX forecasting system is an example of how test particle simulations can be used in real time in a Space Weather context. SPARX is currently operational within the COMESEP Alert System. The performance of the system, which is triggered by detection of a solar flare of class >M1.0 is evaluated by comparing forecasts for flare events between 1997 and 2017 with actual SEP data from the GOES spacecraft.
Forecasting Solar Energetic Particle Events and Associated False Alarms
Authors: Swalwell Bill , Dalla Silvia , Walsh Robert
Published: July 2018

Because of the significant dangers they pose, accurate forecasting of Solar Energetic Particle (SEP) events is vital. Whilst it has long been known that SEP-production is associated with high-energy solar events, forecasting algorithms based upon the observation of these types of solar event suffer from high false alarm rates. Here we analyse the parameters of 4 very high energy solar events which were false alarms, with a view to reaching an understanding as to why SEPs were not detected at Earth. We find that in each case at least two factors were present which have been shown to be detrimental to SEP production.
Physics-Based Modeling Activity from the Solar Surface to the Earth's Atmosphere Including Magnetosphere and Ionosphere at NICT
Authors: Ishii Mamoru , Den Mitsue , Jin Hidekatsu , Kubo Yuki , Kubota Yasubumi , Nakamizo Aoi , Shinagawa Hiroyuki , Shiota Daikou , Tanaka Takashi , Tao Chihiro , Watari Shinichi , Yokoyama Tatsuhiro
Published: July 2018

We present the development of physics-based models of solar-terrestrial regions from the solar surface to the Earth’s atmosphere at NICT. Our models consist of three regions: (1) the solar surface and solar wind, (2) the Earth’s magnetosphere-ionosphere, and (3) a model of the whole atmosphere from the troposphere to the ionosphere, called the Ground to Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA). We also have a solar wind and CME model, Space-weather-forecast-Usable System Anchored by Numerical Operations and Observations (SUSANOO). Furthermore, we have developed a high-resolution plasma bubble model. The coupling of these models is a future work.
The MOTH II Doppler-Magnetographs and Data Calibration Pipeline
Authors: Forte Roberta , Jefferies Stuart M. , Berrilli Francesco , Del Moro Dario , Fleck Bernhard , Giovannelli Luca , Murphy Neil , Pietropaolo Ermanno , Rodgers Wayne
Published: July 2018

The calibration pipeline of the level zero images obtained from the Magneto-Optical filters at Two Heights (MOTH II) instrument is presented. MOTH II consists of two 20 cm aperture instruments, each using a Magneto-Optical Filter (MOF): one at 5896 Å (Na D2-line), the other one at 7700 Å (K I-line). MOTH II instruments thus provide full disk line-of-sight Doppler velocity and magnetic field measurements at two heights in the solar atmosphere. The developed MOTH II pipeline employs a set of standard calibration corrections, a correction for signal leakage, due to the non-ideal behavior of the polarizers, and the geometrical registration between the eight images acquired by four CMOS cameras, relative to two components of the signal in two circular polarization states, in each of the two channels. MOTH II data are used to investigate atmospheric dynamics (e.g., internal gravity waves and magneto-acoustic portals) and Space Weather phenomena. Particularly, flare forecasting algorithms, based on the detection of magnetic active regions (ARs) and associated flare probability estimation, are currently under development. The possible matching of MOTH II data with SDO/HMI and SDO/AIA images into a flux rope model, developed in collaboration between Harvard-Smithsonian CfA and MIT Laboratory for Nuclear Science, is being tested.
SWERTO: a Regional Space Weather Service
Authors: Berrilli Francesco , Casolino Marco , Del Moro Dario , Forte Roberta , Giovannelli Luca , Martucci Matteo , Mergé Matteo , Napoletano Gianluca , Narici Livio , Pietropalo Ermanno , Pucacco Giuseppe , Rizzo Alessandro , Scardigli Stefano , Sparvoli Roberta
Published: July 2018

The Space WEeatherR TOr vergata university (SWERTO) service is an operational Space Weather service based on multi-instrument data from space-based (PAMELA, ALTEA) and ground-based (IBIS, MOTHII) instruments. The service (spaceweather.roma2.infn.it) is located at the Physics Department of the University of Rome Tor Vergata, Italy (UTOV) and will allow registered users to access scientific data from instrumentation available to UTOV researchers through national and international collaborations. It will provide intuitive software for the selection and visualization of such data and results from prototype forecasting codes for flare probability and Solar Energetic Particle (SEP) fluxes. The service is designed to promote access to technical and scientific information by the regional industries which employ technologies vulnerable to Space Weather effects. Basically, SWERTO aims to: i) design and construct a data-base with particle fluxes recorded by space missions and spectro-polarimetric measurements of the solar photosphere; ii) allow an Open Access to the data-base and to prototype forecasts to regional industries involved and exposed to Space Weather effects; iii) implement a tutorial and a FAQ section to help decision makers to became aware of and evaluate the risks from Space Weather events; iv) outreach and customer products. SWERTO has been financed by the Regione Lazio FILAS-RU-2014-1028 grant.
Effects of ICMEs on High Energetic Particles as Observed by the Global Muon Detector Network (GMDN)
Authors: Dal Lago A. , Braga C. R. , de Mendonca R. R. S. , Rockenbach M. , Echer E. , Schuch N. J. , Munakata K. , Kato C. , Kuwabara T. , Kozai M. , Al Jassar H. K. , Sharma M. M. , Tokumaru M. , Duldig M. , Humble J. , Evenson P. , Sabbah I.
Published: July 2018

The Global Muon Detector Network (GMDN) is composed by four ground cosmic ray detectors distributed around the Earth: Nagoya (Japan), Hobart (Australia), Sao Martinho da Serra (Brazil) and Kuwait city (Kuwait). The network has operated since March 2006. It has been upgraded a few times, increasing its detection area. Each detector is sensitive to muons produced by the interactions of ~50 GeV Galactic Cosmic Rays (GCR) with the Earth′s atmosphere. At these energies, GCR are known to be affected by interplanetary disturbances in the vicinity of the earth. Of special interest are the interplanetary counterparts of coronal mass ejections (ICMEs) and their driven shocks because they are known to be the main origins of geomagnetic storms. It has been observed that these ICMEs produce changes in the cosmic ray gradient, which can be measured by GMDN observations. In terms of applications for space weather, some attempts have been made to use GMDN for forecasting ICME arrival at the earth with lead times of the order of few hours. Scientific space weather studies benefit the most from the GMDN network. As an example, studies have been able to determine ICME orientation at the earth using cosmic ray gradient. Such determinations are of crucial importance for southward interplanetary magnetic field estimates, as well as ICME rotation.
METU Data Driven Forecast Models: From the Window of Space Weather IAU Symposium 335
Authors: Tulunay Yurdanur , Tulunay Ersin
Published: July 2018

Space weather processes, in general, are non-linear and time-varying. In such cases ‘data driven models’ such as Neural Network, Fuzzy Logic and Genetic Algorithm based models were proved promising to be used in parallel with the mathematical models based on first physical principles. In particular, with the recent developments in ‘big data’ systems, one of the urgent issues is the development of new signal processing techniques to extract manageable, representative data out of the ‘relevant big data’ to be employed in ‘training’, ‘testing’ and validation phases of model construction. Since 1990, under the EU Frame Work Program Actions, we have developed such models for nowcasting, forecasting, warning and also for filling the data gaps on space weather cases including prediction of orbital spacecraft parameters. In particular, some typical, illustrative examples include the forecasting of the ionospheric critical frequencies foF2, during disturbed conditions, such as solar storms and extreme events; GPS total electon content(TEC); solar flare index during solar maximum and the construction of solar EUV flux variations. The associated input data organisation and the typical errors which have been within the acceptable operational expectations are summarised in terms of absolute values, percent and RMS. The aim of the paper is to show that the data driven approaches are promising for the forecasting of space weather.
Rock Control of River Geometry: The Fraser Canyons
Authors: Rennie Colin D. , Church Michael , Venditti Jeremy G.
Published: July 2018

A 524‐km reach of Fraser River, British Columbia, was traversed, where the channel alternates between gravel‐bedded reaches that are incised into semiconsolidated glacial deposits and bedrock‐bound reaches, including Fraser Canyon. Continuous centerline acoustic Doppler current profiler survey and observations of bedrock confinement, supplemented with measurements on air photos, reveal the influence of bedrock on channel properties. The surveyed reach was subdivided into 10 morphological reaches, ranging from dominance by alluvial gravel‐bed channels to dominantly rock‐walled canyons. Measured data were grouped within each reach based on the presence of bedrock on both banks, one bank, or neither bank. From alluvial to mixed to canyon‐dominated reaches, river widths decreased while water depths, flow velocities, water surface slopes, and bed shear stresses increased. Within reaches, subreaches with bedrock on both banks were narrower and deeper with higher bed shear stresses but, at the observed stage, had lower depth‐averaged velocity and water surface slope than partly confined and alluvial (unconfined) subreaches. A conceptual model is presented representing a bedrock river as an alternating series of relatively low gradient, deep, rock‐walled pools and steep semialluvial or alluvial sections. Downstream hydraulic geometry relations have scaling exponents expected for alluvial channels provided that the alluvial and rock‐influenced sections are analyzed separately. In Fraser River, canyons become relatively narrower downstream, apparently in response to increasing rock uplift during the Quaternary period. The observations are compared against prior semitheoretical frameworks established to explain variations in width, slope, and channel shape along rockbound channels.
Dysregulated iron metabolism in polycythemia vera: etiology and consequences
Authors: Ginzburg Yelena Z. , Feola Maria , Zimran Eran , Varkonyi Judit , Ganz Tomas , Hoffman Ronald
Published: July 2018

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm. Virtually all PV patients are iron deficient at presentation and/or during the course of their disease. The co-existence of iron deficiency and polycythemia presents a physiological disconnect. Hepcidin, the master regulator of iron metabolism, is regulated by circulating iron levels, erythroblast secretion of erythroferrone, and inflammation. Both decreased circulating iron and increased erythroferrone levels, which occur as a consequence of erythroid hyperplasia in PV, are anticipated to suppress hepcidin and enable recovery from iron deficiency. Inflammation which accompanies PV is likely to counteract hepcidin suppression, but the relatively low serum ferritin levels observed suggest that inflammation is not a major contributor to the dysregulated iron metabolism. Furthermore, potential defects in iron absorption, aberrant hypoxia sensing and signaling, and frequency of bleeding to account for iron deficiency in PV patients have not been fully elucidated. Insufficiently suppressed hepcidin given the degree of iron deficiency in PV patients strongly suggests that disordered iron metabolism is an important component of the pathobiology of PV. Normalization of hematocrit levels using therapeutic phlebotomy is the most common approach for reducing the incidence of thrombotic complications, a therapy which exacerbates iron deficiency, contributing to a variety of non-hematological symptoms. The use of cytoreductive therapy in high-risk PV patients frequently works more effectively to reverse PV-associated symptoms in iron-deficient relative to iron-replete patients. Lastly, differences in iron-related parameters between PV patients and mice with JAK2 V617F and JAK2 exon 12 mutations suggest that specific regions in JAK2 may influence iron metabolism by nuanced changes of erythropoietin receptor signaling. In this review, we comprehensively discuss the clinical consequences of iron deficiency in PV, provide a framework for understanding the potential dysregulation of iron metabolism, and present a rationale for additional therapeutic options for iron-deficient PV patients.
Organoid cultures recapitulate esophageal adenocarcinoma heterogeneity providing a model for clonality studies and precision therapeutics
Authors: Li Xiaodun , Francies Hayley E. , Secrier Maria , Perner Juliane , Miremadi Ahmad , Galeano-Dalmau Núria , Barendt William J. , Letchford Laura , Leyden Genevieve M. , Goffin Emma K. , Barthorpe Andrew , Lightfoot Howard , Chen Elisabeth , Gilbert James , Noorani Ayesha , Devonshire Ginny , Bower Lawrence , Grantham Amber , MacRae Shona , Grehan Nicola , Wedge David C. , Fitzgerald Rebecca C. , Garnett Mathew J.
Published: July 2018

Esophageal adenocarcinoma (EAC) incidence is increasing while 5-year survival rates remain less than 15%. A lack of experimental models has hampered progress. We have generated clinically annotated EAC organoid cultures that recapitulate the morphology, genomic, and transcriptomic landscape of the primary tumor including point mutations, copy number alterations, and mutational signatures. Karyotyping of organoid cultures has confirmed polyclonality reflecting the clonal architecture of the primary tumor. Furthermore, subclones underwent clonal selection associated with driver gene status. Medium throughput drug sensitivity testing demonstrates the potential of targeting receptor tyrosine kinases and downstream mediators. EAC organoid cultures provide a pre-clinical tool for studies of clonal evolution and precision therapeutics.
Spontaneous cortical activity transiently organises into frequency specific phase-coupling networks
Authors: Vidaurre Diego , Hunt Laurence T. , Quinn Andrew J. , Hunt Benjamin A. E. , Brookes Matthew J. , Nobre Anna C. , Woolrich Mark W.
Published: July 2018

Frequency-specific oscillations and phase-coupling of neuronal populations are essential mechanisms for the coordination of activity between brain areas during cognitive tasks. Therefore, the ongoing activity ascribed to the different functional brain networks should also be able to reorganise and coordinate via similar mechanisms. We develop a novel method for identifying large-scale phase-coupled network dynamics and show that resting networks in magnetoencephalography are well characterised by visits to short-lived transient brain states, with spatially distinct patterns of oscillatory power and coherence in specific frequency bands. Brain states are identified for sensory, motor networks and higher-order cognitive networks. The cognitive networks include a posterior alpha (8–12 Hz) and an anterior delta/theta range (1–7 Hz) network, both exhibiting high power and coherence in areas that correspond to posterior and anterior subdivisions of the default mode network. Our results show that large-scale cortical phase-coupling networks have characteristic signatures in very specific frequency bands, possibly reflecting functional specialisation at different intrinsic timescales.
Transforming ground mica into high-performance biomimetic polymeric mica film
Authors: Pan Xiao-Feng , Gao Huai-Ling , Lu Yang , Wu Chun-Yan , Wu Ya-Dong , Wang Xiang-Ying , Pan Zhi-Qiang , Dong Liang , Song Yong-Hong , Cong Huai-Ping , Yu Shu-Hong
Published: July 2018

Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h−1 can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices.
Long range electronic phase separation in CaFe3O5
Authors: Hong Ka. H. , Arevalo-Lopez Angel M. , Cumby James , Ritter Clemens , Attfield J. Paul
Published: July 2018

Incomplete transformations from ferromagnetic to charge ordered states in manganite perovskites lead to phase-separated microstructures showing colossal magnetoresistances. However, it is unclear whether electronic matter can show spontaneous separation into multiple phases distinct from the high temperature state. Here we show that paramagnetic CaFe3O5 undergoes separation into two phases with different electronic and spin orders below their joint magnetic transition at 302 K. One phase is charge, orbital and trimeron ordered similar to the ground state of magnetite, Fe3O4, while the other has Fe2+/Fe3+charge averaging. Lattice symmetry is unchanged but differing strains from the electronic orders probably drive the phase separation. Complex low symmetry materials like CaFe3O5 where charge can be redistributed between distinct cation sites offer possibilities for the generation and control of electronic phase separated nanostructures.
Evolution of cooperativity in the spin transition of an iron(II) complex on a graphite surface
Authors: Kipgen Lalminthang , Bernien Matthias , Ossinger Sascha , Nickel Fabian , Britton Andrew J. , Arruda Lucas M. , Naggert Holger , Luo Chen , Lotze Christian , Ryll Hanjo , Radu Florin , Schierle Enrico , Weschke Eugen , Tuczek Felix , Kuch Wolfgang
Published: July 2018

Cooperative effects determine the spin-state bistability of spin-crossover molecules (SCMs). Herein, the ultimate scale limit at which cooperative spin switching becomes effective is investigated in a complex [Fe(H2B(pz)2)2(bipy)] deposited on a highly oriented pyrolytic graphite surface, using x-ray absorption spectroscopy. This system exhibits a complete thermal- and light-induced spin transition at thicknesses ranging from submonolayers to multilayers. On increasing the coverage from 0.35(4) to 10(1) monolayers, the width of the temperature-induced spin transition curve narrows significantly, evidencing the buildup of cooperative effects. While the molecules at the submonolayers exhibit an apparent anticooperative behavior, the multilayers starting from a double-layer exhibit a distinctly cooperative spin switching, with a free-molecule-like behavior indicated at around a monolayer. These observations will serve as useful guidelines in designing SCM-based devices.
Structural insights into SorCS2–Nerve Growth Factor complex formation
Authors: Leloup Nadia , Chataigner Lucas M. P. , Janssen Bert J. C.
Published: July 2018

Signaling of SorCS receptors by proneurotrophin ligands regulates neuronal plasticity, induces apoptosis and is associated with mental disorders. The detailed structure of SorCS2 and its extracellular specificity are unresolved. Here we report crystal structures of the SorCS2–NGF complex and unliganded SorCS2 ectodomain, revealing cross-braced SorCS2 homodimers with two NGF dimers bound in a 2:4 stoichiometry. Five out of six SorCS2 domains directly contribute to dimer formation and a C-terminal membrane proximal unreported domain, with an RNA recognition motif fold, locks the dimer in an intermolecular head-to-tail interaction. The complex structure shows an altered SorCS2 conformation indicating substantial structural plasticity. Both NGF dimer chains interact exclusively with the top face of a SorCS2 β-propeller. Biophysical experiments reveal that NGF, proNGF, and proBDNF bind at this site on SorCS2. Taken together, our data reveal a structurally flexible SorCS2 receptor that employs the large β-propeller as a ligand binding platform.
Surfaces away from horizons are not thermodynamic
Authors: Wang Zhi-Wei , Braunstein Samuel L.
Published: July 2018

Since the 1970s, it has been known that black-hole (and other) horizons are truly thermodynamic. More generally, surfaces which are not horizons have also been conjectured to behave thermodynamically. Initially, for surfaces microscopically expanded from a horizon to so-called stretched horizons, and more recently, for more general ordinary surfaces in the emergent gravity program. To test these conjectures we ask whether such surfaces satisfy an analogue to the first law of thermodynamics (as do horizons). For static asymptotically flat spacetimes we find that such a first law holds on horizons. We prove that this law remains an excellent approximation for stretched horizons, but counter-intuitively this result illustrates the insufficiency of the laws of black-hole mechanics alone from implying truly thermodynamic behavior. For surfaces away from horizons in the emergent gravity program the first law fails (except for spherically symmetric scenarios), thus undermining the key thermodynamic assumption of this program.
Provable compressed sensing quantum state tomography via non-convex methods
Authors: Kyrillidis Anastasios , Kalev Amir , Park Dohyung , Bhojanapalli Srinadh , Caramanis Constantine , Sanghavi Sujay
Published: July 2018

With nowadays steadily growing quantum processors, it is required to develop new quantum tomography tools that are tailored for high-dimensional systems. In this work, we describe such a computational tool, based on recent ideas from non-convex optimization. The algorithm excels in the compressed sensing setting, where only a few data points are measured from a low-rank or highly-pure quantum state of a high-dimensional system. We show that the algorithm can practically be used in quantum tomography problems that are beyond the reach of convex solvers, and, moreover, is faster and more accurate than other state-of-the-art non-convex approaches. Crucially, we prove that, despite being a non-convex program, under mild conditions, the algorithm is guaranteed to converge to the global minimum of the quantum state tomography problem; thus, it constitutes a provable quantum state tomography protocol.
A first-principles study of the effect of vacancy defects on the electronic structures of greigite (Fe3S4)
Authors: Wu Min , Zhou Xia , Huang Shibei , Cheng Jianlin , Ding Zhenyu
Published: July 2018

Greigite (Fe3S4) is a ferrimagnetic mineral with an inverse spinel structure. Besides its importance in the bio-geochemical cycle, it also has great potential applications for its unique properties such as its half metallic electronic structure at ambient condition. However, it has been challenging to get high purity and crystallinity samples of greigite in experiment, and the defect effect on the electronic structure of greigite was not clear. In the present study, first-principles calculations have been performed to investigate the ground state electronic structure of greigite with monovacancy. It is found that, with an vacancy concentration lower than 3.6%, the greigite with an Fe vacancy is an insulator with charge orderings, while the greigite with a S vacancy becomes a half-metal and has a magnetic moment of <4.0 μB per formula unit. The present result helps to understand the absence of the Verwey transition and the magnetic property of greigite measured in experiment. The understanding of the electronic structure of defective greigite could also be utilized to manipulate the properties of greigite for spintronic applications.
Cloning and characterization of EgGDSL, a gene associated with oil content in oil palm
Authors: Zhang Yingjun , Bai Bin , Lee May , Alfiko Yuzer , Suwanto Antonius , Yue Gen Hua
Published: July 2018

Oil palm (Elaeis guineensis, Jacq.) is a key tropical oil crop, which provides over one third of the global vegetable oil production, but few genes related to oil yield have been characterized. In this study, a GDSL esterase/lipase gene, which was significantly associated with oil content, was isolated from oil palm and designated as EgGDSL. Its functional characterization was carried out through ectopic expression in Arabidopsis ecotype Col-0. It was shown that expression of EgGDSL in Arabidopsis led to the increased total fatty acid content by 9.5% compared with the wild type. Further analysis of the fatty acid composition revealed that stearic acid (18:0) increased in the seeds of the transgenic lines, but the levels of linoleic acid (18:2) plus 11-eicosenoic acid drastically declined. Quantitative real-time PCR (qPCR) revealed that in oil palm, EgGDSL was highly expressed in mesocarp followed by leaf, and the expression level was very low in the root. The expression level of EgGDSL gene began to increase at two months after flowering (MAF) and reached its peak by four MAF, then declined rapidly, and reached its lowest level during the mature period (6 MAF). The EgGDSL gene was more highly expressed in oil palm trees with high oil content than that with low oil content, demonstrating that the transcription level of EgGDSL correlated with the amount of oil accumulation. The gene may be valuable for engineering fatty acid metabolism in crop improvement programmes and for marker-assisted breeding.
tDCS to premotor cortex changes action verb understanding: Complementary effects of inhibitory and excitatory stimulation
Authors: Gijssels Tom , Ivry Richard B. , Casasanto Daniel
Published: July 2018

Processing the meaning of action language correlates with somatotopic activity in premotor cortex (PMC). A previous neurostimulation study supported a causal contribution of PMC activity to action verb understanding, but the direction of the effect was unexpected: inhibiting PMC made participants respond faster to action verbs. Here we investigated the effects of PMC excitation and inhibition on action verb understanding using tDCS. Right-handed participants received tDCS stimulation with the anodal electrode (presumed to be excitatory) and cathodal electrode (presumed to be inhibitory) placed over left and right PMC, respectively, or with the reverse configuration. After completing the stimulation protocol, participants made lexical decisions on unimanual action verbs (e.g., throw) and abstract verbs (e.g., think). tDCS configuration selectively affected how accurately participants responded to unimanual action verbs. When the anode was positioned over left PMC we observed a relative impairment in performance for right-hand responses (i.e. the hand with which these participants typically perform unimanual actions). By contrast, when the cathode was positioned over left PMC we observed a relative improvement. tDCS configuration did not differentially affect responses to abstract verbs. These complementary effects of excitatory and inhibitory tDCS clarify the functional role of premotor hand areas in understanding action language.