bluuebunny/crossref_metadata_2025 huggingface dataset:
A survey on UML model smells detection techniques for software refactoring
Authors: Mumtaz Haris , Alshayeb Mohammad , Mahmood Sajjad , Niazi Mahmood
Published: February 2019

Bad smells tend to have a negative impact on software by degrading its quality. It is beneficial to detect model smells to avoid their propagation to later stages of software development. The objective of this paper is to present the state‐of‐the‐art research on techniques for detecting UML model bad smells. The detection techniques are compared and evaluated using a proposed evaluation framework. The framework consists of two parts. The first part of the framework compares the techniques in terms of the implemented approach, the investigated model, and the explored model smells, while the experimental design is explored in the second part of the framework. We found that the detection of bad smells in class and sequence diagrams is accomplished via design patterns, software metrics, and predefined rules, while model smells in use cases are detected using metrics and predefined rules. We also found that the class diagram is the most investigated UML model in the context of model smell detection, whereas there is a lack of work on other UML models. In addition, there is a scarcity of independent studies on sequence diagrams. Furthermore, the studies investigating class diagrams are mostly validated, whereas use case diagrams and sequence diagrams are rarely validated.
Atmospheric aerosol analysis at the PIXE–RBS beamline in the University of Jordan Van de Graaff accelerator (JUVAC)
Authors: Sa'adeh Hanan , Chiari Massimo
Published: February 2019

The University of Jordan Van de Graaff accelerator (JUVAC) was devoted many years ago to promote scientific research through the installation of several beamlines based on nuclear techniques. It constitutes the first and unique, till now, ion beam analysis facility in Jordan. Among these techniques, the JUVAC has recently installed, with the financial and technical aid of the International Atomic Energy Agency, a combination of particle‐induced X‐ray emission (PIXE) and Rutherford backscattering spectrometry (RBS). A new X‐ray detector has been installed, and the system has been tested for aerosol analysis using a set of thin MicroMatter standards. This manuscript includes a brief description of the combined PIXE–RBS beamline with some results, particularly those obtained by PIXE. The low‐energy proton beam adds a technical limitation to attain optimum analytical performance. However, a simulation of the RBS spectrum of protons on aerosol filter indicates that the RBS measurement for some elements (e.g., Pb) can replace the PIXE one.
DEFT: a program for operators in EFT
Authors: Gripaios Ben , Sutherland Dave
Published: February 2019

Abstract

We describe a Python-based computer program, DEFT, for manipulating operators in effective field theories (EFTs). In its current incarnation, DEFT can be applied to 4-dimensional, Poincaré invariant theories with gauge group SU(3) × SU(2) × U(1), such as the Standard Model (SM), but a variety of extensions (e.g. to lower dimensions or to an arbitrary product of unitary gauge groups) are possible. Amongst other features, the program is able to: (i) check whether an input list of Lagrangian operators (of a given dimension in the EFT expansion) is a basis for the space of operators contributing to S-matrix elements, once redundancies (such as Fierz-Pauli identities, integration by parts, and equations of motion) are taken into account; (ii) generate such a basis (where possible) from an input algorithm; (iii) carry out a change of basis. We describe applications to the SM (where we carry out a number of non-trivial cross-checks) and extensions thereof, and outline how the program may be of use in precision tests of the SM and in the ongoing search for new physics at the LHC and elsewhere. The code and instructions can be downloaded from http://web.physics.ucsb.edu/~dwsuth/DEFT/.
Stable wormholes in scalar-tensor theories
Authors: Franciolini Gabriele , Hui Lam , Penco Riccardo , Santoni Luca , Trincherini Enrico
Published: February 2019

Abstract

We reconsider the issue of whether scalar-tensor theories can admit stable wormhole configurations supported by a non-trivial radial profile for the scalar field. Using a recently proposed effective theory for perturbations around static, spherically symmetric backgrounds, we show that scalar-tensor theories of “beyond Horndeski” type can have wormhole solutions that are free of ghost and gradient instabilities. Such solutions are instead forbidden within the more restrictive “Horndeski” class of theories.
Living orthogonally: quasi-universal extra dimensions
Authors: Arun Mathew Thomas , Choudhury Debajyoti , Sachdeva Divya
Published: February 2019

Abstract

The minimal Universal Extra Dimension scenario is highly constrained owing to opposing constraints from the observed relic density on the one hand, and the non-observation of new states at the LHC on the other. Simple extensions in five-dimensions can only postpone the inevitable. Here, we propose a six-dimensional alternative with the key feature being that the SM quarks and leptons are localized on orthogonal directions whereas gauge bosons traverse the entire bulk. Several different realizations of electroweak symmetry breaking are possible, while maintaining agreement with low energy observables. This model is not only consistent with all the current constraints opposing the minimal Universal Extra Dimension scenario but also allows for a multi-TeV dark matter particle without the need for any fine-tuning. In addition, it promises a plethora of new signatures at the LHC and other future experiments.
New physics from high energy tops
Authors: Farina Marco , Mondino Cristina , Pappadopulo Duccio , Ruderman Joshua T.
Published: February 2019

Abstract

Precision measurements of high energy top quarks at the LHC constitute a powerful probe of new physics. We study the effect of four fermion operators involving two tops and two light quarks on the high energy tail of the

$$ t\overline{t} $$

t

t
¯

invariant mass distribution. We use existing measurements at a center of mass energy of 13 TeV, and state of the art calculations of the Standard Model contribution, to derive bounds on the coefficients of these operators. We estimate the projected reach of the LHC at higher luminosities and discuss the validity of these limits within the Effective Field Theory description. We find that current measurements constrain the mass scale of these operators to be larger than about 1–2 TeV, while we project that future LHC data will be sensitive to mass scales of about 3–4 TeV. We apply our bounds to constrain composite Higgs models with partial compositeness and models with approximate flavor symmetries. We find our limits to be most relevant to flavor non-universal models with a moderately large coupling of the heavy new physics states to third generation quarks.
Modular forms in the spectral action of Bianchi IX gravitational instantons
Authors: Fan Wentao , Fathizadeh Farzad , Marcolli Matilde
Published: February 2019

Abstract

We prove a modularity property for the heat kernel and the Seeley-deWitt coefficients of the heat kernel expansion for the Dirac-Laplacian on the Bianchi IX gravitational instantons. We prove, via an isospectrality result for the Dirac operators, that each term in the expansion is a vector-valued modular form, with an associated ordinary (meromorphic) modular form of weight 2. We discuss explicit examples related to well known modular forms. Our results show the existence of arithmetic structures in Euclidean gravity models based on the spectral action functional.
Resident satisfaction regarding surgical training programme in Eastern Saudi Arabia: A cross-sectional study
Authors: Aldossary Mohammed Yousef , Alnaimi Manal , Almabyouq Fatimah , Alsofyani Tlal , AlJahdali Akram , Al-Buainain Hussah
Published: February 2019

ABSTRACT

Background:

The satisfaction of surgical residents with their training programs is a key indicator for program effectiveness. This survey was conducted to assess the level of perceived satisfaction of surgical residents with the current training programs in Eastern Saudi Arabia.

Materials and methods:

Resident satisfaction was measured by questionnaire in 119 selected participants at 9 training centers in Eastern Saudi Arabia, as part of the general surgery residency program of Saudi Commission for Health Specialties.

Results:

The survey response rate was 69.7% (83/119) resident participants. A total of 37 (44.6%) residents expressed dissatisfaction with their current training programs. The residents were least satisfied with research opportunities (78.3%), followed by faculty didactic involvement (59%), mentorship (51.8%), and case volume (41%) offered in their programs.

Conclusion:

The general low level of satisfaction among surgical residents in Eastern Saudi Arabia warrants a national review of the current programs. Resident satisfaction should be considered as a potent factor while conferring accreditation to surgical training programs across the country.

Highlights:
National Action Plans on Business and Human Rights: Progress or Mirage?
Authors: CANTÚ RIVERA Humberto
Published: February 2019

As of October 2018, 21 states have adopted National Action Plans on Business and Human Rights (NAPs), with several more in different phases of development. This is an important political step to raise awareness of the importance of intragovernmental policy coherence and of the need to move forward to prevent human rights abuses linked to business activity. However, despite the global intergovernmental support to such policy strategies, the actual effectiveness of NAPs needs to be called into question: do they represent progress, or are they a mirage to block possible avenues of development? Currently existing NAPs have done little (yet) to ensure more effective protection in key policy areas, including trade and investment, state-owned enterprises, and particularly in relation to legislative developments and access to remedy. This contribution seeks to analyse the merits of developing NAPs, the importance of ensuring they become only the very first step towards a more effective protection of human rights, and to question whether their importance needs to be adjusted to what they really are: policy tools with limited effects and with a politically linked time frame.
Viscous fingering phenomena in the early stage of polymer membrane formation
Authors: Hopp-Hirschler Manuel , Safdari Shadloo Mostafa , Nieken Ulrich
Published: February 2019

Currently, the most important preparation process for porous polymer membranes is the phase inversion process. While applied for several decades in industry, the mechanism that leads to diverse morphology is not fully understood today. In this work, we present time resolved experiments using light microscopy that indicate viscous fingering during the early stage of pore formation in porous polymer membranes. Numerical simulations using the smoothed particle hydrodynamics method are also performed based on Cahn–Hilliard and Navier–Stokes equations to investigate the formation of viscous fingers in miscible and immiscible systems. The comparison of pore formation characteristics in the experiment and simulation shows that immiscible viscous fingering is present; however, it is only relevant in specific preparation set-ups similar to Hele-Shaw cells. In experiments, we also observe the formation of Liesegang rings. Enabling diffusive mass transport across the immiscible interface leads to Liesegang rings in the simulation. We conclude that further investigations of Liesegang pattern as a relevant mechanism in the formation of morphology in porous polymer membranes are necessary.
Personnel Politics: Elections, Clientelistic Competition and Teacher Hiring in Indonesia
Authors: Pierskalla Jan H , Sacks Audrey
Published: February 2019

What is the effect of increased electoral competition on patronage politics? If programmatic appeals are not credible, institutional reforms that move politics from an elite- to a mass-focused and more competitive environment increase patronage efforts. This leads to an overall surge and notable spike in discretionary state hiring in election years. The study tests this prediction in the context of Indonesia’s decentralized education sector. The authors exploit the exogenous phasing in and timing of elections in Indonesian districts for causal identification. They find evidence of election-related increases in the number of contract teachers on local payrolls and increases in civil service teacher certifications, which dramatically increases salaries. These effects are particularly pronounced for districts in which the former authoritarian ruling party is in competition with new entrants.
A high-fidelity, fully immersive simulation course to replicate ENT and head and neck emergencies
Authors: Hogg E S , Kinshuck A J , Littley N , Lau A , Tandon S , Lancaster J
Published: February 2019

Background

Simulation-based training has a fundamental role in medical education as it allows the learner to gain experience managing emergencies in a safe, controlled environment.

Methods

This 1-day course consisted of eight high-fidelity simulation scenarios, followed by a video-assisted debrief focusing on the technical and non-technical (communication skills, teamwork, leadership and situational awareness) aspects of managing ENT and head and neck emergencies.

Results

Eight courses have run since June 2014. Post-course questionnaires demonstrated that candidates’ confidence scores in managing airway and head and neck emergencies increased following completion of the course (p < 0.0001).

Conclusion

This was the first fully immersive ENT simulation course developed in the region. The learning objectives for each scenario were mapped to the ENT Intercollegiate Surgical Curriculum Programme. Feedback from the course indicated a continued demand for this style of training, leading to its inclusion in the training calendar.
Developmental cascades to children's conduct problems: The role of prenatal substance use, socioeconomic adversity, maternal depression and sensitivity, and children's conscience
Authors: Ettekal Idean , Eiden Rina D. , Nickerson Amanda B. , Molnar Danielle S. , Schuetze Pamela
Published: February 2019

This study investigated the longitudinal associations among prenatal substance use, socioeconomic adversity, parenting (maternal warmth, sensitivity, and harshness), children's self-regulation (internalization of rules and conscience), and conduct problems from infancy to middle childhood (Grade 2). Three competing conceptual models including cascade (indirect or mediated), additive (cumulative), and transactional (bidirectional) effects were tested and compared. The sample consisted of 216 low-income families (primary caretaker and children; 51% girls; 74% African American). Using a repeated-measures, multimethod, multi-informant design, a series of full panel models were specified. Findings primarily supported a developmental cascade model, and there was some support for additive effects. More specifically, maternal prenatal substance use and socioeconomic adversity in infancy were prospectively associated with lower levels of maternal sensitivity. Subsequently, lower maternal sensitivity was associated with decreases in children's conscience in early childhood, and in turn, lower conscience predicted increases in teacher-reported conduct problems in middle childhood. There was also a second pathway from sustained maternal depression (in infancy and toddlerhood) to early childhood conduct problems. These findings demonstrated how processes of risk and resilience collectively contributed to children's early onset conduct problems.
Caregiver–adolescent co-reminiscing and adolescents’ individual recollections of a devastating tornado: Associations with enduring posttraumatic stress symptoms
Authors: Hendrickson Michelle L. , Abel Madelaine R. , Vernberg Eric M. , McDonald Kristina L. , Lochman John E.
Published: February 2019

Although disaster-related posttraumatic stress symptoms (PTSS) typically decrease in intensity over time, some youth continue to report elevated levels of PTSS many years after the disaster. The current study examines two processes that may help to explain the link between disaster exposure and enduring PTSS: caregiver emotion socialization and youth recollection qualities. One hundred and twenty-two youth (ages 12 to 17) and their female caregivers who experienced an EF-4 tornado co-reminisced about the event, and adolescents provided independent recollections between 3 and 4 years after the tornado. Adolescent individual transcripts were coded for coherence and negative personal impact, qualities that have been found to contribute to meaning making. Parent–adolescent conversations were coded for caregiver egocentrism, a construct derived from the emotion socialization literature to reflect the extent to which the caregiver centered the conversation on her own emotions and experiences. Egocentrism predicted higher youth PTSS, and this association was mediated by the coherence of adolescents’ narratives. The association between coherence and PTSS was stronger for youth who focused more on the negative personal impacts of the tornado event during their recollections. Results suggest that enduring tornado-related PTSS may be influenced in part by the interplay of caregiver emotion socialization practices and youth recollection qualities.
The effectiveness of dietary workplace interventions: a systematic review of systematic reviews
Authors: Schliemann Désirée , Woodside Jayne V
Published: February 2019

Objective

To summarise findings of systematic reviews that distinctively report dietary intervention components and their effects on diet-, health- and economic-related outcomes in the workplace setting.

Design

MEDLINE, Embase, CINAHL, Web of Science, Cochrane Library and Google Scholar were searched in December 2014 and the search was updated in August 2017.

Results

The search identified 1137 titles, of which nineteen systematic reviews from the initial search and two systematic reviews from the updated search met the inclusion criteria (twenty-one systematic reviews, published in twenty-two papers). Most systematic reviews were of moderate quality and focused on dietary behaviour change outcomes and some health-related biomarkers. Evidence was strongest for interventions to increase fruit and vegetable intake, reduce fat intake, aid weight loss and reduce cholesterol. Few reported workplace-related and evaluation outcomes.

Conclusions

These findings suggest that workplace dietary interventions can positively influence diet and health outcomes. Suggestions for effective interventions components have been made.
Singular Agreement in Special Partitive Constructions in Dutch
Authors: Hogeweg Lotte , Ramachers Stefanie , de Hoop Helen
Published: February 2019

Dutch partitive constructions of the typeone of the (few) X who Yshow a striking pattern of singular subject-verb agreement in their relative clause. This paper presents a corpus study showing that the prescriptively “incorrect” singular agreement pattern is in fact the dominant pattern in Dutch. In order to explain this, we argue that this type of partitive construction often has a specific function in context, namely, to point out that the subject is special or extraordinary, usually for the reason presented by the relative clause. We apply a usage-based approach to this construction within the framework of Construction Grammar, arguing that the prevalent implicature of the subject’s specialness has become a conventionalized part of the meaning of the construction. This analysis then can be used to explain the syntactic pattern of singular agreement within the relative clause. A similar albeit less pronounced pattern can be found in German.*
TOWARDS A NON-ARCHIMEDEAN ANALYTIC ANALOG OF THE BASS–QUILLEN CONJECTURE
Authors: Kerz Moritz , Saito Shuji , Tamme Georg
Published: February 2019

We suggest an analog of the Bass–Quillen conjecture for smooth affinoid algebras over a complete non-archimedean field. We prove this in the rank-1 case, i.e. for the Picard group. For complete discretely valued fields and regular affinoid algebras that admit a regular model (automatic if the residue characteristic is zero) we prove a similar statement for the Grothendieck group of vector bundles$K_{0}$.
LOGIC FOR EXACT ENTAILMENT
Authors: FINE KIT , JAGO MARK
Published: February 2019

An exact truthmaker for A is a state which, as well as guaranteeing A’s truth, is wholly relevant to it. States with parts irrelevant to whether A is true do not count as exact truthmakers for A. Giving semantics in this way produces a very unusual consequence relation, on which conjunctions do not entail their conjuncts. This feature makes the resulting logic highly unusual. In this paper, we set out formal semantics for exact truthmaking and characterise the resulting notion of entailment, showing that it is compact and decidable. We then investigate the effect of various restrictions on the semantics. We also formulate a sequent-style proof system for exact entailment and give soundness and completeness results.
Entwicklung und erste Validierung eines Situational-Judgement-Instruments zur Erfassung von Kompetenzen im Bereich des Ressourcenmanagements (ReMI)
Authors: Waldeyer Julia , Fleischer Jens , Wirth Joachim , Leutner Detlev
Published: February 2019

Zusammenfassung. Ein Studium stellt Lernende vor umfangreiche Herausforderungen im Bereich des selbstregulierten Lernens, insbesondere im Bereich des Ressourcenmanagements. Entsprechend sollte Ressourcenmanagement prädiktiv für Lernerfolg im Studium sein. Jedoch mangelt es bisher an validen Instrumenten zur Erfassung entsprechender Kompetenzen. Es wird daher ein neues Instrument vorgestellt, das Ressourcenmanagementkompetenzen in Form von konditionalem Strategiewissen als auch in Form von Defiziten bei der Strategieanwendung erfasst. Dieses Instrument wurde hinsichtlich seiner Validität mit einer Stichprobe von N = 198 Erstsemesterstudierenden überprüft. Konfirmatorische Faktorenanalysen bestätigen die theoretisch angenommene Faktorenstruktur. Zudem zeigen sich erwartungskonforme konvergente und diskriminante Korrelationen mit externen Kriterien. Prognostische Validität zeigt sich in der Form, dass Ressourcenmanagementkompetenzen, erfasst über das neue Instrument, Studienerfolg inkrementell zur Abiturnote und schlussfolgerndem Denken als Indikator für Intelligenz signifikant vorhersagen können.
Karriere-Ressourcen messen
Authors: Hirschi Andreas , Hänggli Madeleine , Nagy Noemi , Baumeler Franziska , Johnston Claire , Spurk Daniel
Published: February 2019

Zusammenfassung. Die existierende Literatur schlägt eine Vielzahl von potentiellen Prädiktoren für Karriereerfolg vor, welche in ihrer Menge kaum auf eine ökonomische Art erhoben werden können. Um diesen Umstand anzugehen, haben Hirschi, Nagy, Baumeler, Johnston und Spurk (2018) den Karriere-Ressourcen Fragebogen (CRQ; Career Resources Questionnaire) entwickelt und in einer englischsprachigen Version validiert. Basierend auf einer Integration von theoretischer und metaanalytischer Forschung misst der Fragebogen 13 distinkte Faktoren, welche 4 übergeordnete Dimensionen repräsentieren: Wissen und Kompetenzen, Motivation, Umfeld und Aktivitäten bezüglich Karriere. In der vorliegenden Studie wird eine Validierung der deutschsprachigen Version mittels N = 1 666 Personen (Studierende und Berufstätige) vorgenommen. Die Ergebnisse bestätigen die Reliabilität sowie die Faktorstruktur des Fragebogens. Mittels Relative-Weight-Analysen konnte zudem die Wichtigkeit von verschiedenen Faktoren für unterschiedliche Arten von Karriereerfolg gezeigt werden. Das Messinstrument bietet Forschenden und Praktizierenden eine ökonomische, reliable und valide Möglichkeit, um Schlüsselfaktoren für Karriereerfolg zu erfassen.
„Berliner Inventar zur Angehörigenbelastung – Demenz Praxisversion (BIZA-D-PV)“ auch für den nicht demenziellen Bereich?
Authors: Hetzel Christian , Alles Torsten , Froböse Ingo
Published: February 2019

Zusammenfassung. Pflegende Angehörige sind eine vulnerable Zielgruppe mit zunehmender Bedeutung. Es gibt insbesondere im nicht-demenziellen Bereich wenig Evidenz zu Unterstützungs- und Entlastungsangeboten. Für indikationsübergreifende Evaluationsstudien hat das mehrdimensionale Berliner Inventar zur Angehörigenbelastung – Demenz Praxisversion (BIZA-D-PV) konzeptionelles Potenzial. Es soll die Teststatistik des BIZA-D-PV im nicht-demenziellen und im demenziellen Bereich geprüft werden. Das Instrument hat 33 Items in 7 Skalen. Die Datenbasis waren 161 pflegende Angehörige im nicht-demenziellen Bereich und 133 im demenziellen Bereich. Es wurden explorative Faktorenanalysen und ein Multiple Indicators Multiple Causes (MIMIC) Modell eingesetzt. Die faktorielle Validität und die Reliabilitäten sind in beiden Stichproben vergleichbar und gut. Populationsheterogenität sowie Relationen der Skalen insbesondere mit selbstberichteter Depressivität deuten auf Konstruktvalidität hin. Das BIZA-D-PV ist auch im nicht-demenziellen Bereich ein reliables und faktoriell valides Instrument. Hinweise auf Konstruktvalidität liegen vor, bedürfen aber der weiteren Fundierung.
Latitude Dependence of Geomagnetic Paleosecular Variation and its Relation to the Frequency of Magnetic Reversals: Observations From the Cretaceous and Jurassic
Authors: Doubrovine Pavel V. , Veikkolainen Toni , Pesonen Lauri J. , Piispa Elisa , Ots Siim , Smirnov Aleksey V. , Kulakov Evgeniy V. , Biggin Andrew J.
Published: February 2019

Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.
Remote Sensing of Chlorophyll Fluorescence in the Ocean Using Imaging Spectrometry: Toward a Vertical Profile of Fluorescence
Authors: Erickson Z. K. , Frankenberg C. , Thompson D. R. , Thompson A. F. , Gierach M.
Published: February 2019

Chlorophyll fluorescence measurements provide valuable information on phytoplankton abundance and physiology. High spectral resolution measurements from the aircraft‐mounted Portable Remote Imaging SpectroMeter (PRISM) allow for a more robust and informative fluorescence measurement than previous methods. An increase in radiation in the fluorescence wavelength range is approximated by a skew‐normal distribution. Positive skew suggests the influence of water attenuation and motivates the use of an inverse retrieval model to solve for the most likely vertical distribution of fluorescence quantum yield. This approach is tested with theoretical fluorescence profiles and applied to a PRISM flightline located in southern Drake Passage, Southern Ocean during austral summer. The resulting profiles suggest vertical structure in fluorescence quantum yield in the upper 10 m, which matches expectations from in situ studies. The framework developed in this paper can be applied to current and future satellite missions, providing more information on phytoplankton concentrations, vertical profiles, and physiology.
Electrical Investigation of Natural Lawsonite and Application to Subduction Contexts
Authors: Pommier Anne , Williams Quentin , Evans Rob L. , Pal Ishita , Zhang Zhou
Published: February 2019

We report an experimental investigation of the electrical properties of natural polycrystalline lawsonite from Reed Station, CA. Lawsonite represents a particularly efficient water reservoir in subduction contexts, as it can carry about 12 wt % water and is stable over a wide pressure range. Experiments were performed from 300 to about 1325 °C and under pressure from 1 to 10 GPa using a multi‐anvil apparatus. We observe that temperature increases lawsonite conductivity until fluids escape the cell after dehydration occurs. At a fixed temperature of 500 °C, conductivity measurements during compression indicate electrical transitions at about 4.0 and 9.7 GPa that are consistent with crystallographic transitions from orthorhombic C to P and from orthorhombic to monoclinic systems, respectively. Comparison with lawsonite structure studies indicates an insignificant temperature dependence of these crystallographic transitions. We suggest that lawsonite dehydration could contribute to (but not solely explain) high conductivity anomalies observed in the Cascades by releasing aqueous fluid at a depth (~50 km) consistent with the basalt‐eclogite transition. In subduction settings where the incoming plate is older and cooler (e.g., Japan), lawsonite remains stable to great depth. In these cooler settings, lawsonite could represent a vehicle for deep water transport and the subsequent triggering of melt that would appear electrically conductive, though it is difficult to uniquely identify the contributions from lawsonite on field electrical profiles in these more deep‐seated domains.
High‐Pressure Single‐Crystal Elasticity and Thermal Equation of State of Omphacite and Their Implications for the Seismic Properties of Eclogite in the Earth's Interior
Authors: Hao Ming , Zhang Jin S. , Pierotti Caroline E. , Ren Zhiyuan , Zhang D.
Published: February 2019

Omphacite is a major mineral phase of eclogite, which provides the main driving force for the slab subduction into the Earth's interior. We have measured the single‐crystal elastic moduli of omphacite at high pressures for the first time up to 18 GPa at ambient temperature using Brillouin spectroscopy. A least squares fit of the velocity‐pressure data to the third‐order finite strain equation of state yields KS0′ = 4.5 (3), G0′ = 1.6 (1) with ρ0 = 3.34 (1) g/cm3, KS0 = 123 (3) GPa, and G0 = 74 (2) GPa. In addition, the synchrotron single‐crystal X‐ray diffraction data have been collected up to 18 GPa and 700 K. The fitting to Holland‐Powell thermal‐pressure equation of state yields KT0′ = 4.6 (5) and α0 = 2.7 (8) × 10−5 K−1. Based on the obtained thermoelastic parameters of omphacite, the anisotropic seismic velocities of eclogite are modeled and compared with pyrolite between 200 and 500 km. The largest contrast between the eclogite and pyrolite in terms of seismic properties is observed between ~310 and 410 km.
Ocean Surface Turbulence in Newly Formed Marginal Ice Zones
Authors: Smith Madison , Thomson Jim
Published: February 2019

Near‐surface turbulent kinetic energy dissipation rates are altered by the presence of sea ice in the marginal ice zone, with significant implications for exchanges at the air‐ice‐ocean interface. Observations spanning a range of conditions are used to parameterize dissipation rates in marginal ice zones with relatively thin, newly formed ice, and two regimes are identified. In both regimes, the turbulent dissipation rates are matched to the turbulent input rate, which is formulated as the surface stress acting on roughness elements moving at an effective transfer velocity. In marginal ice zones with waves, the short waves are the roughness elements, and the phase speed of these waves is the effective transfer velocity. The wave amplitudes are attenuated by the ice, and thus, the size of the roughness elements is reduced; this is parameterized as a reduction in the effective transfer velocity. When waves are sufficiently small, the ice floes are the roughness elements, and the relative velocity between the sea ice and the ocean is the effective transfer velocity. A scaling is introduced to determine the appropriate transfer velocity in a marginal ice zone based on wave height, ice thickness and concentration, and ice‐ocean shear. The results suggest that turbulence underneath new sea ice is mostly related to the wind forcing and that marginal ice zones generally have less turbulence than the open ocean under similar wind forcing.
Distribution Patterns of Picosized and Nanosized Phytoplankton Assemblages in the East China Sea and the Yellow Sea: Implications on the Impacts of Kuroshio Intrusion
Authors: Zhao Yue , Yu Ren‐Cheng , Kong Fan‐Zhou , Wei Chuan‐Jie , Liu Ze , Geng Hui‐Xia , Dai Li , Zhou Zheng‐Xi , Zhang Qing‐Chun , Zhou Ming‐Jiang
Published: February 2019

Kuroshio, the strongest west boundary current of the Pacific Ocean, has significant impacts on the oceanographic conditions and ecological processes of the Pacific‐Asian marginal seas through exchange of water, heat, and materials. In two cruises organized in the East China Sea (ECS) and the Yellow Sea in the spring 2014, observations of picosized and nanosized phytoplankton assemblages using flow cytometry reflected potential impacts of Kuroshio intrusion on phytoplankton communities, particularly in the ECS. The distribution pattern of Prochlorococcus in the ECS clearly depicts the intrusion route of Nearshore Kuroshio Branch Current from the main stream of Kuroshio northeast to Taiwan Island to the coastal waters adjacent to the Changjiang River estuary, an important “red tide zone” in the coastal waters of China. High abundance of photosynthetic nanoeukaryotes in the coastal waters adjacent to the Changjiang River estuary reflects the occurrence of diatom and dinoflagellate blooms during the investigation. The presence of Prochlorococcus in the coastal waters adjacent to the Changjiang River estuary offers a strong evidence that waters and materials associated with Nearshore Kuroshio Branch Current could be transported into the red tide zone adjacent to the Changjiang River estuary and will affect dynamics of harmful algal blooms in this region.
Characterization and Quantification of Atmospheric Mercury Sources Using Passive Air Samplers
Authors: McLagan David S. , Monaci Fabrizio , Huang Haiyong , Lei Ying Duan , Mitchell Carl P. J. , Wania Frank
Published: February 2019

The Minamata Convention on Mercury (Hg) requires improved atmospheric Hg monitoring and characterization of Hg sources. Here we demonstrate how a network of passive air samplers (PASs) can be used cost effectively to determine the spatial distribution of gaseous Hg and estimate atmospheric Hg emissions at contaminated sites. Gaseous Hg concentrations were mapped around a former Hg mine in the Monte Amiata district in Italy using simultaneous deployments of PASs across local and regional spatial scale grids. The concentration maps help visualize with great detail and precision the dispersal of gaseous Hg from a contaminated site, revealing even subtle effects of wind, season, and minor sources. Emissions estimated from the empirical data (80 ± 40 and 150 ± 75 kg/year for October and July, respectively) were robust to changes in the most uncertain parameters (excess Hg in the air above the mine and advection rate) and compared well to previous estimates for this and other closed Hg mines. This PAS‐based approach has a number of advantages: (i) concurrent deployments of multiple samplers constrain concentration changes to spatial variability only, (ii) time‐averaged data over longer periods negate biases related to short‐term, infrequent measurements, (iii) more spatially representative estimates of Hg distributions and emissions can be made at a fraction of the cost, and (iv) use is easy, especially in difficult terrain. Time‐averaged data across a broad area are also most pertinent for assessing chronic human exposure, especially in terms of the inhalation of Hg by workers and residents living close to contaminated sites.
Patterns of genetic differentiation and the footprints of historical migrations in the Iberian Peninsula
Authors: Bycroft Clare , Fernandez-Rozadilla Ceres , Ruiz-Ponte Clara , Quintela Inés , Carracedo Ángel , Donnelly Peter , Myers Simon
Published: February 2019

The Iberian Peninsula is linguistically diverse and has a complex demographic history, including a centuries-long period of Muslim rule. Here, we study the fine-scale genetic structure of its population, and the genetic impacts of historical events, leveraging powerful, haplotype-based statistical methods to analyse 1413 individuals from across Spain. We detect extensive fine-scale population structure at extremely fine scales (below 10 Km) in some regions, including Galicia. We identify a major east-west axis of genetic differentiation, and evidence of historical north to south population movement. We find regionally varying fractions of north-west African ancestry (0–11%) in modern-day Iberians, related to an admixture event involving European-like and north-west African-like source populations. We date this event to 860–1120 CE, implying greater genetic impacts in the early half of Muslim rule in Iberia. Together, our results indicate clear genetic impacts of population movements associated with both the Muslim conquest and the subsequent Reconquista.
Ultrastretchable and superior healable supercapacitors based on a double cross-linked hydrogel electrolyte
Authors: Li Huili , Lv Tian , Sun Huanhuan , Qian Guiju , Li Ning , Yao Yao , Chen Tao
Published: February 2019

Due to inherently poor healable and stretchable features, the most explored polyvinyl alcohol-based gel electrolytes cannot well meet the requirements of stretchable, healable and multifunctional supercapacitors. Here, we report a hydrogel of a copolymer cross-linked by double linkers of Laponite (synthetic hectorite-type clay) and graphene oxide. The resultant hydrogel shows high mechanical stretchability, excellent ionic conductivity, and superior healable performance. Along with designing wrinkled-structure electrodes, supercapacitors fabricated by using this hydrogel as a gel electrolyte not only exhibit ultrahigh mechanical stretchability of 1000%, but also achieve repeated healable performance under treatments of both infrared light irradiation and heating. More significantly, a broken/healed supercapacitor also possesses an ultrahigh stretchability up to 900% with slight performance decay. This hydrogel electrolyte could be easily functionalized by introducing other functional components, and extended for use in other portable and wearable energy related devices with multifunction.
Trait-based community assembly and succession of the infant gut microbiome
Authors: Guittar John , Shade Ashley , Litchman Elena
Published: February 2019

The human gut microbiome develops over early childhood and aids in food digestion and immunomodulation, but the mechanisms driving its development remain elusive. Here we use data curated from literature and online repositories to examine trait-based patterns of gut microbiome succession in 56 infants over their first three years of life. We also develop a new phylogeny-based approach of inferring trait values that can extend readily to other microbial systems and questions. Trait-based patterns suggest that infant gut succession begins with a functionally variable cohort of taxa, adept at proliferating rapidly within hosts, which gradually matures into a more functionally uniform cohort of taxa adapted to thrive in the anoxic gut and disperse between anoxic patches as oxygen-tolerant spores. Trait-based composition stabilizes after the first year, while taxonomic turnover continues unabated, suggesting functional redundancy in the traits examined. Trait-based approaches powerfully complement taxonomy-based approaches to understanding the mechanisms of microbial community assembly and succession.
Satb1 regulates the effector program of encephalitogenic tissue Th17 cells in chronic inflammation
Authors: Yasuda Keiko , Kitagawa Yohko , Kawakami Ryoji , Isaka Yoshitaka , Watanabe Hitomi , Kondoh Gen , Kohwi-Shigematsu Terumi , Sakaguchi Shimon , Hirota Keiji
Published: February 2019

The genome organizer, special AT-rich sequence-binding protein-1 (Satb1), plays a pivotal role in the regulation of global gene networks in a cell type-dependent manner and is indispensable for the development of multiple cell types, including mature CD4+ T, CD8+ T, and Foxp3+ regulatory T cells in the thymus. However, it remains unknown how the differentiation and effector program of the Th subsets in the periphery are regulated by Satb1. Here, we demonstrate that Satb1 differentially regulates gene expression profiles in non-pathogenic and pathogenic Th17 cells and promotes the pathogenic effector program of encephalitogenic Th17 cells by regulating GM-CSF via Bhlhe40 and inhibiting PD-1 expression. However, Satb1 is dispensable for the differentiation and non-pathogenic functions of Th17 cells. These results indicate that Satb1 regulates the specific gene expression and function of effector Th17 cells in tissue inflammation.
Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling
Authors: Hamnett Ryan , Crosby Priya , Chesham Johanna E. , Hastings Michael H.
Published: February 2019

The suprachiasmatic nucleus (SCN) co-ordinates circadian behaviour and physiology in mammals. Its cell-autonomous circadian oscillations pivot around a well characterised transcriptional/translational feedback loop (TTFL), whilst the SCN circuit as a whole is synchronised to solar time by its retinorecipient cells that express and release vasoactive intestinal peptide (VIP). The cell-autonomous and circuit-level mechanisms whereby VIP synchronises the SCN are poorly understood. We show that SCN slices in organotypic culture demonstrate rapid and sustained circuit-level circadian responses to VIP that are mediated at a cell-autonomous level. This is accompanied by changes across a broad transcriptional network and by significant VIP-directed plasticity in the internal phasing of the cell-autonomous TTFL. Signalling via ERK1/2 and tuning by its negative regulator DUSP4 are critical elements of the VIP-directed circadian re-programming. In summary, we provide detailed mechanistic insight into VIP signal transduction in the SCN at the level of genes, cells and neural circuit.
Smart scanning for low-illumination and fast RESOLFT nanoscopy in vivo
Authors: Dreier Jes , Castello Marco , Coceano Giovanna , Cáceres Rodrigo , Plastino Julie , Vicidomini Giuseppe , Testa Ilaria
Published: February 2019

RESOLFT fluorescence nanoscopy can nowadays image details far beyond the diffraction limit. However, signal to noise ratio (SNR) and temporal resolution are still a concern, especially deep inside living cells and organisms. In this work, we developed a non-deterministic scanning approach based on a real-time feedback system which speeds up the acquisition up to 6-fold and decreases the light dose by 70–90% for in vivo imaging. Also, we extended the information content of the images by acquiring the complete temporal evolution of the fluorescence generated by reversible switchable fluorescent proteins. This generates a series of images with different spatial resolution and SNR, from conventional to RESOLFT images, which combined through a multi-image deconvolution algorithm further enhances the effective resolution. We reported nanoscale imaging of organelles up to 35 Hz and actin dynamics during an invasion process at a depth of 20–30 µm inside a living Caenorhabditis elegans worm.
Magnetization reversal driven by low dimensional chaos in a nanoscale ferromagnet
Authors: Montoya Eric Arturo , Perna Salvatore , Chen Yu-Jin , Katine Jordan A. , d’Aquino Massimiliano , Serpico Claudio , Krivorotov Ilya N.
Published: February 2019

Energy-efficient switching of magnetization is a central problem in nonvolatile magnetic storage and magnetic neuromorphic computing. In the past two decades, several efficient methods of magnetic switching were demonstrated including spin torque, magneto-electric, and microwave-assisted switching mechanisms. Here we experimentally show that low-dimensional magnetic chaos induced by alternating spin torque can strongly increase the rate of thermally-activated magnetic switching in a nanoscale ferromagnet. This mechanism exhibits a well-pronounced threshold character in spin torque amplitude and its efficiency increases with decreasing spin torque frequency. We present analytical and numerical calculations that quantitatively explain these experimental findings and reveal the key role played by low-dimensional magnetic chaos near saddle equilibria in enhancement of the switching rate. Our work unveils an important interplay between chaos and stochasticity in the energy assisted switching of magnetic nanosystems and paves the way towards improved energy efficiency of spin torque memory and logic.
Enhanced flexoelectricity at reduced dimensions revealed by mechanically tunable quantum tunnelling
Authors: Das Saikat , Wang Bo , Paudel Tula R. , Park Sung Min , Tsymbal Evgeny Y. , Chen Long-Qing , Lee Daesu , Noh Tae Won
Published: February 2019

Flexoelectricity is a universal electromechanical coupling effect whereby all dielectric materials polarise in response to strain gradients. In particular, nanoscale flexoelectricity promises exotic phenomena and functions, but reliable characterisation methods are required to unlock its potential. Here, we report anomalous mechanical control of quantum tunnelling that allows for characterising nanoscale flexoelectricity. By applying strain gradients with an atomic force microscope tip, we systematically polarise an ultrathin film of otherwise nonpolar SrTiO3, and simultaneously measure tunnel current across it. The measured tunnel current exhibits critical behaviour as a function of strain gradients, which manifests large modification of tunnel barrier profiles via flexoelectricity. Further analysis of this critical behaviour reveals significantly enhanced flexocoupling strength in ultrathin SrTiO3, compared to that in bulk, rendering flexoelectricity more potent at the nanoscale. Our study not only suggests possible applications exploiting dynamic mechanical control of quantum effect, but also paves the way to characterise nanoscale flexoelectricity.
Capturing chemical intuition in synthesis of metal-organic frameworks
Authors: Moosavi Seyed Mohamad , Chidambaram Arunraj , Talirz Leopold , Haranczyk Maciej , Stylianou Kyriakos C. , Smit Berend
Published: February 2019

We report a methodology using machine learning to capture chemical intuition from a set of (partially) failed attempts to synthesize a metal-organic framework. We define chemical intuition as the collection of unwritten guidelines used by synthetic chemists to find the right synthesis conditions. As (partially) failed experiments usually remain unreported, we have reconstructed a typical track of failed experiments in a successful search for finding the optimal synthesis conditions that yields HKUST-1 with the highest surface area reported to date. We illustrate the importance of quantifying this chemical intuition for the synthesis of novel materials.