bluuebunny/crossref_metadata_2025 huggingface dataset:
Brands, ‘weightless’ firms and global value chains: the organisational impact of trade mark law
Authors: Griffiths Andrew
Published: April 2019

The Rana Plaza disaster of April 2013 was the most prominent of several incidents that have highlighted poor standards of business behaviour in the supply chains of well-known brands. Analysis of these incidents has attributed these poor standards to an institutional structure in which lead firms with strategic power outsource production into global value chains and pursue business models that involve rapid product upgrading and require low costs and fast turnarounds in production such as the garment industry's ‘fast fashion’ business model. This paper aims to complement that analysis by showing how trade marks, as the main legal anchors of brands, have reinforced the strategic power of lead firms, enabled them to outsource production and encouraged them to adopt business models of this kind. The paper will also evaluate the claim that brands mitigate their harmful effects by transmitting countervailing pressure back onto their owners because they provide salient targets for bad publicity and blame, as coverage of the Rana Plaza disaster showed, which can threaten their owners with reputational damage. It will be argued that this countervailing pressure has a limited effect and cannot be relied on without more to address the issues that the Rana Plaza disaster revealed.
Profinite groups with restricted centralizers of commutators
Authors: Detomi Eloisa , Morigi Marta , Shumyatsky Pavel
Published: April 2019

A groupGhas restricted centralizers if for eachginGthe centralizer$C_G(g)$either is finite or has finite index inG. A theorem of Shalev states that a profinite group with restricted centralizers is abelian-by-finite. In the present paper we handle profinite groups with restricted centralizers of word-values. We show that ifwis a multilinear commutator word andGa profinite group with restricted centralizers ofw-values, then the verbal subgroupw(G) is abelian-by-finite.
Candidate traits in elections: when good news for selection is bad news for accountability
Authors: Schnakenberg Keith
Published: April 2019

We analyze a two-election political agency model with moral hazard and adverse selection in which candidates have observable traits such as job qualifications that help voters to imperfectly predict politicians' types. Candidate's traits can help voters select good types of politicians. However, selecting candidates with good traits can reduce accountability because the voter cannot commit to throw out politicians with good traits who produce bad outcomes. This result explains when and why voters may sometimes select candidates who they believe are less likely to be competent.
Dietary patterns modify the association between fat mass and obesity-associated genetic variants and changes in obesity phenotypes
Authors: Hosseini-Esfahani Firoozeh , Koochakpoor Glareh , Mirmiran Parvin , Daneshpour Maryam S. , Azizi Fereidoun
Published: April 2019

The present study investigated whether dietary patterns could interact with fat mass and obesity-associated (FTO) polymorphisms in relation to changes in BMI and waist circumference (WC) over 3⋅6 years of follow-up. Subjects were selected from participants of the Tehran Lipid and Glucose Study (n 4292, 43⋅2 % male). Dietary data were collected using a valid and reliable FFQ. Dietary patterns were determined using factor analysis. The genotypes of polymorphisms (rs1421085, rs1121980, rs17817449, rs8050136, rs9939973 and rs3751812) were determined. Genetic risk score (GRS) was calculated using the weighted method. Mean ages of men and women were 42·6 (sd 14) and 40⋅4 (sd 13) years, respectively. The healthy (e.g. vegetables and fruits) and the Western dietary patterns (WDP; e.g. soft drinks and fast foods) were extracted. In carriers of the risk alleles rs1121980, rs1421085, rs8050136, rs1781799 and rs3751812, BMI was approximately 2-fold higher in individuals in the higher quartile of WDP score, compared with the first quartile (P < 0⋅05). WC increased with increasing WDP score in carriers of the risk alleles rs1121980 and rs3751812, but not in individuals who did not carry any risk alleles. BMI and WC increased to a greater extent in the high GRS group while increasing quartiles of the WDP score, compared with the low GRS group (BMI change; Q1: 1⋅04 (se 0⋅34) v. Q4: 2⋅26 (se 0⋅36)) (WC change; Q1: 0⋅47 (se 0⋅32) v. Q4: 0⋅95 (se 0⋅34)) (P
interaction < 0⋅05). These results suggest that adults with higher genetic predisposition to obesity are more susceptible to the harmful effects of adherence to the WDP, which emphasised the need to reduce the consumption of unhealthy foods for the prevention of obesity.
The fishing behaviour of Metopograpsus messor (Decapoda: Grapsidae) and the use of pneumatophore-borne vibrations for prey-localizing in an arid mangrove setting
Authors: Giraldes Bruno Welter , Chatting Mark , Smyth David
Published: April 2019

This study presents the first documented observations of a brachyuran crab's proactive fishing behaviour in conjunction with mangrove pneumatophores which are employed as prey-localization devices. All ecological data were recorded in situ using simple behavioural observations, visual census and field experiments. Field experiments were based on stimulus-response and ecological surveys on random displacement. Assemblages of Metopograpsus messor were observed daily performing a foraging/predatory tide-related cyclic behaviour pattern in an arid mangrove ecosystem which experiences challenging environmental conditions. Prey-localizing behaviour was observed during the flood tide when pneumatophore-borne vibrations were used to identify potential prey. The prey simulation field experiment (where a single pneumatophore was stimulated by knocking) showed that in >93% of instances a crab approached the exact pneumatophore being stimulated. As water levels increased during the tidal cycle M. messor was observed climbing pneumatophores. The crabs anchored themselves to the pneumatophore just above the water level with their pereiopods. The chelipeds were positioned in a pincher-like trap, and remained in a ‘capture-position’ waiting for prey to move within striking range. This characteristic fishing behaviour was performed daily by a population of M. messor. Ecological observations suggest that both these predatory behaviours are associated with the fish Aphanius dispar dispar in a direct prey–predator relation. Evidence suggests that these fishing behaviours evolved due to characteristics within the M. messor phylogeny (foraging in intertidal zones; daily displacement following tidal levels; high sensitivity to vibrations; and an opportunist diet) and its associated environment (presence of pneumatophores and high availability of a fish resource).
Reflections on 100 years of IAU
Authors: Cesarsky Catherine
Published: April 2019

One hundred years ago, the International Astronomical Union was created, one of the very first Unions dedicated to the advancement of a discipline and the promotion of international collaboration and exchange. In 100 years, astronomy has made huge progress, and the IAU has greatly expanded in volume and purpose. In recent years, it has become more and more active in education, astronomy for development and dissemination of astronomy to a large public.
Jorge Sahade: First Latin American IAU President
Authors: Cidale Lydia S.
Published: April 2019

Prof. Jorge Sahade (1915–2012) was the first Latin American President of the International Astronomical Union (1985–1988). From then on, he had a very active participation as president, vice-president, and organizing committee member of several Commissions and Divisions of the IAU, related to stellar astrophysics and exchange of astronomers. Prof. J. Sahade was born in Argentina and was one of the first students graduated in astronomy at the National University of La Plata. He served as director of the Astronomical Observatory of Córdoba (1953–1955) and of the Observatory of La Plata (1968–1969). He was the first Dean of the Faculty of Exact Sciences of the National University of La Plata. He promoted the purchase of a 2.15-m diameter telescope, today located in the Complejo Astronómico El Leoncito, San Juan, Argentina. He founded the Institute of Astronomy and Physics of Space (IAFE) in Buenos Aires and was its first director (1971–1974). He was also director of the “Comisión Nacional de Actividades Espaciales” (the Argentina Space Activity Agency) and promoted the inclusion of Argentina as a partnership of the Gemini Observatory. Prof. Sahade also focused on the development of the astronomy in Latin America and this led to the creation of the “Liga Latinoamericana de Astronomía” (nowadays LIADA).

His research field was interacting binary systems and he published about 150 papers, among them is the well-known discovery of the “Struve-Sahade effect”. I met him when he was 70 years old; he was a very enthusiastic astronomer, who travellled everywhere to promote the astronomy in Latin America (Argentina, Perú, Honduras). Among his last dreams was the creation of a Latin American Institute to develop and enhance astrophysics in South and Central America, the revival of UV astronomy and many more impressive works that he would have liked to end and publish.
Patterns to scientific internationalism: What can a comparative history of IAU and IUPAP teach us?
Authors: Lalli Roberto
Published: April 2019

International scientific institutions are preferred settings to explore prominent topics in the transnational approaches to the recent history of science. These include: the dichotomy between universalism and contextualism in the historical evolution of exact sciences; the historical transformation of the ideals of scientific internationalism; the tensions between these historically changing ideals and scientists’ national allegiances; the balance between scientific and diplomatic activities of such institutions; and the issue of how the complex ideological, socio-political roles these institutions play affected the actual evolution of science.

Inspired by these overreaching themes, the paper presents a conceptual framework for pursuing a comparative analysis of IAU and IUPAP. A bird’s-eye view of the parallel historical developments of these two unions shows that, in spite of their common origins in the highly politicized context of the post-WWI reconstruction of international cooperation, IAU and IUPAP followed diverging trajectories in many respects. It is argued that a deeper study of these differences might give important insights to properly understand the relevance of specific disciplines’ scientific needs in the way the ideals and practices of scientific internationalism were actualized through the 20th century.
International cooperation in astronomy before the IAU
Authors: Trimble Virginia
Published: April 2019

I have written elsewhere from a (mostly) celebratory point of view about early international astronomical projects. This version looks at some of the same projects, but from a less cheerful point of view.
On the eve of the 100th anniversary of IAU Commission 19/A2 “Rotation of the Earth”
Authors: Malkin Zinovy , Gross Richard , McCarthy Dennis , Brzeziński Aleksander , Capitaine Nicole , Dehant Véronique , Huang Chengli , Schuh Harald , Vondrák Jan , Yatskiv Yaroslav
Published: April 2019

IAU Commission 19 began in 1919 with the birth of the IAU at the Brussels Conference, where Standing Committee 19 on Latitude Variations was established as one of 32 standing committees. At the first IAU General Assembly in 1922, Standing Committee 19 became Commission 19 “Variation of Latitude”. In the beginning, the main topic of the Commission was the investigation of polar motion. Later, its activities included observations and theory of Earth rotation and connections between Earth orientation variations and geophysical phenomena. As a result, in 1964 at the XII IAU General Assembly, the Commission was renamed “Rotation of the Earth”. The investigation of Earth orientation variations is primarily based on observations of natural and artificial celestial objects. Therefore, maintenance of the international terrestrial and celestial reference frames, as well as the coordinate transformation between the frames and the improvement of the model of precession/nutation, have always been among the primary Commission topics. In 1987, the IAU through Commissions 19 and 31 “Time” established, jointly with the International Union of Geodesy and Geophysics, what is now known as the International Earth Rotation and Reference Systems Service. Commission 19 continued to work to develop methods to improve the accuracy and understanding of Earth orientation variations and related reference systems and frames as well as theoretical studies of Earth rotation. In 2015, Commission 19 was renewed as Commission A2 “Rotation of the Earth” continuing Commission 19’s functions and linking the astronomical community to other scientific organizations such as the International Association of Geodesy, International VLBI Service for Geodesy and Astrometry, International GNSS Service, International Laser Ranging Service and International DORIS Service. During its entire history, IAU Commission 19/A2 has always worked in close cooperation with these and other related services to improve the accuracy and consistency of the Earth orientation parameters and celestial and terrestrial reference frames.
IAU Commission 25, and the development of early photometric systems
Authors: Sterken Christiaan
Published: April 2019

The International Astronomical Union was conceived in 1918, and was formed one year later in Brussels. One of the 32 initial Commissions was the Committee on Stellar Photometry that later on became IAU Commission 25 Astronomical Photometry and Polarimetry, and since 2015 Commission B6 with the same name. The initial functions to be exercised by the Committee were

(a)

to advise in the matter of notation, nomenclature, definitions, conventions, etc., and

(b)

to plan and execute investigations requiring the cooperation of several observers or institutions.

The basic philosophy was that IAU Commission 25 was to be an advisory body, rather than a decision-making committee that imposes its regulations. This position was reconfirmed at the 10th IAU General Assembly in 1958.

From the early days on, the Commission members engaged in the teaching of the principles of photometric measurement – either via the Commission meetings and the ensuing reports, or via external means, such as lectures and publications. The topics of instruction dealt with absorption of light in the atmosphere, the modification imposed by the character of the receiving apparatus, the unequal response of different receivers to a same stimulus, and variations in the data-recorder response from one experiment to another.

From the 1930s on it was suggested that IAU Commission 25 takes responsibility in matters of standard stars, standard filters and standard calibration methods.

During the first half-century since its foundation, Commission 25 was an active forum for discussions on the basic principles of astronomical photometry, including the associated problems of transformability of magnitudes and colour indices from one instrumental configuration to another. During the second half-century of its existence, the Commission has served as a sort of news agency reporting on the developments in detector engineering, filter technology and data reduction. All along the Commission members were committed to accuracy and precision, a struggle that was primarily driven by the jumps forward in performance and sensitivity of every new detector that was introduced.

The development over one century shows that the Commission was continuously touching on the philosophy of precise measurement, where accurate measuring – for a select group of pioneers – was an end in itself.

This presentation looks back on the opinions of key players in the photometric standardisation debate, and briefly presents two case studies that illustrate the illusionary accuracy reached over a century in determining, as Commission member Ralph Allan Sampson put it, “a detail like magnitude”.
Urania as a 100-year old magazine, coeval with the IAU
Authors: Czart Krzysztof , Mikołajewski Maciej
Published: April 2019

“Urania” is a popular Polish astronomy magazine, one of the oldest in the world among present journals of this type. The first official issue was published in 1922, but the origins of “Urania” are even older, as in 1919 and 1920 there were published a few issues of a predecessor of “Urania” with the same title. So we can say that “Urania” and the IAU are of the same age. The role of “Urania” has been changing during these 100 years, but the magazine has been always a very important entity for the astronomical community in Poland, both professional and amateur. Thousands of pages contain an historical record of astronomy in Poland, as well as the progress of astronomy in the world, including IAU activities.
The future of the International Schools for Young Astronomers (ISYA)
Authors: Aretxaga Itziar
Published: April 2019

The 5-decade old ISYA program is evaluated in the context of the experience gathered in the field: 41 schools organized in 27 countries with a total of more than 1400 students to date. In the new era of fast internet connectivity, social media, virtual networks, big data and machine learning, the value of face-to-face graduate schools for regions with limited up-to-date astrophysics research is presented, together with the plan to develop the ISYA program into the next decade.
The Spectral Classification of Stars over the last 200, 100, 75 years and in the future
Authors: Corbally Christopher J. , Gray Richard O.
Published: April 2019

This year 2018 has great historical and current significance for stellar spectral classification. Two hundred years ago in Reggio Emilia, Italy, was born Angelo Secchi, a pioneer of observing and classifying the spectra of stars. At the beginning of the IAU, almost a hundred years ago, one of its original Commissions was entitled the Spectral Classification of Stars, from which was generated Commission 45, Spectral Classification and Multi-band Colour Indices. And seventy-five years ago, was published the system-changing MKK, An Atlas of Stellar Spectra. Through this necessarily brief, historical view we shall recall how spectral classification, supported internationally by the IAU, continually updated its techniques, while remaining anchored to standards. This has ensured that the MK classification process stays very relevant to the initial characterizing of stars in the 21st century era of large spectral surveys.
The Argentinean attempts to prove the Theory of General Relativity: the total solar eclipses of 1912, 1914 and 1919
Authors: Paolantonio Santiago , Pelliza Leonardo , Mallamaci Claudio C. , Camino Néstor , Orellana Mariana , Garca Beatriz
Published: April 2019

The aim of this work is to provide new information about the history of astronomical science and the efforts of the people that have enriched our discipline, often coming from anonymity. Here we compile the attempts made in our country to prove the theory of General Relativity through experiments that, as they were without success, fell into oblivion.
Astronomy and the IAU in the next century
Authors: van Dishoeck Ewine F.
Published: April 2019

The first hundred years of the IAU have witnessed scientific and technological progress in astronomy beyond anything imagined at the time the IAU was founded in 1919. What will the next hundred years bring? How do we engage with other sciences, now that our field is becoming more multidisciplinary? How do we convince governments to continue funding our field, in particular the ever more powerful telescopes? And how do we continue to inspire and involve people worldwide in our exciting adventure through space? A brief forward look into the next decade and beyond is presented, with some challenges highlighted.
Reducing mental health-related stigma among medical and nursing students in low- and middle-income countries: a systematic review
Authors: Heim E. , Henderson C. , Kohrt B. A. , Koschorke M. , Milenova M. , Thornicroft G.
Published: April 2019

Aims

This systematic review compiled evidence on interventions to reduce mental health-related stigma among medical and nursing students in low- and middle-income countries (LMICs). Primary outcomes were stigmatising attitudes and discriminatory behaviours.

Methods

Data collection included two strategies. First, previous systematic reviews were searched for studies that met the inclusion criteria of the current review. Second, a new search was done, covering the time since the previous reviews, i.e. January 2013 to May 2017. Five search concepts were combined in order to capture relevant literature: stigma, mental health, intervention, professional students in medicine and nursing, and LMICs. A qualitative analysis of all included full texts was done with the software MAXQDA. Full texts were analysed with regard to the content of interventions, didactic methods, mental disorders, cultural adaptation, type of outcome measure and primary outcomes. Furthermore, a methodological quality assessment was undertaken.

Results

A total of nine studies from six countries (Brazil, China, Malaysia, Nigeria, Somaliland and Turkey) were included. All studies reported significant results in at least one outcome measure. However, from the available literature, it is difficult to draw conclusions on the most effective interventions. No meta-analysis could be calculated due to the large heterogeneity of intervention content, evaluation design and outcome measures. Studies with contact interventions (either face-to-face or video) demonstrated attitudinal change. There was a clear lack of studies focusing on discriminatory behaviours. Accordingly, training of specific communication and clinical skills was lacking in most studies, with the exception of one study that showed a positive effect of training interview skills on attitudes. Methods for cultural adaptation of interventions were rarely documented. The methodological quality of most studies was relatively low, with the exception of two studies.

Conclusions

There is an increase in studies on anti-stigma interventions among professional students in LMICs. Some of these studies used contact interventions and showed positive effects. A stronger focus on clinical and communication skills and behaviour-related outcomes is needed in future studies.
Transnational Localism: Empowerment through Standard Setting in Small-Scale Fisheries
Authors: Penca Jerneja
Published: April 2019

In order to advance both the mapping and theorizing of transnational law, this article considers a range of tactics used by small-scale fisheries (SSFs) in Europe and North America to improve market access, political influence, and legal recognition. Transnational law enables the framing of initiatives not only as implementation practices that occur as a result of international law, but also as transnational regulation in support of SSFs. The article uses the case study of SSFs to draw attention to the rise of ‘transnational localism’. This is defined as the reinforcement of local-specific approaches (reflecting local ecologies, values, and socio-economic specificities) within a transnational structure that provides support and recognition. It offers an alternative to the view that globalization necessitates global, uniform regulatory solutions. Transnational localism challenges the fascination with large certification schemes such as that administered by the Marine Stewardship Council (MSC) in fisheries governance. It implies a need to reconcile transnational challenges with heterogeneous values and community approaches. To capture the simultaneous demand for the local and transnational within transnational law, this article proposes treating the described empowerment tactics within the scope of transnational standards. This requires a rethinking of standards away from fixed technical rules that are uniformly applicable across the globe.
Resveratrol does not affect leptin while it has regulatory effects on liver glycogen levels in exercised and non-exercised rats
Authors: Baltaci Abdulkerim Kasim , Duran Mursel Oguzhan , Mogulkoc Rasim , Oltulu Pembe , Avunduk Mustafa Cihat
Published: April 2019

Abstract. Resveratrol (RES) is a well-known phytocompound and food component which has antioxidative and multifunctional bioactivities. The present study aims to examine how resveratrol administration affects plasma leptin and liver glycogen levels in rats subjected to an acute swimming exercise bout. The study was carried out on Wistar-Albino type adult male rats, each group include 7 rats. Group 1, Control Group. Group 2, Control Swimming Group: The group fed on a standard diet and subjected to an acute swimming exercise bout for 30 minutes at the end of the study. Group 3, Resveratrol Group: The group fed on a standard diet and given (10 mg/kg) resveratrol in drinking water for four weeks. Group 4, Resveratrol + Swimming Group: The group fed on a standard diet, given (10 mg/kg) resveratrol in drinking water for four weeks and subjected to a 30-minute acute swimming exercise at the end of the study. Plasma leptin levels using ELISA method (ng/l) and liver glycogen levels were determined by using histochemical method (number/0.1 mm2). Four weeks resveratrol administration to exercised and not-exercised rats did not cause a change in plasma leptin levels. Liver glycogen levels were 17.00 ± 3.16; 14.12 ± 2.98; 20.82 ± 1.97; 16.38 ± 1.27 (mean ± sd); respectively in groups 1, 2, 3, 4. Resveratrol administration to rats subjected to a bout of acute swimming exercise produced an effect that prevented the decrease in liver glycogen (p < 0.05). The study highlights that resveratrol supplementation may have regulatory effects on liver glycogen levels in exercised and non-exercised rats.
Sorbitol enhances the physicochemical stability of B12 vitamers
Authors: Hadinata Lie Andrew , V Chandra-Hioe Maria , Arcot Jayashree
Published: April 2019

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.
Individuelle Entwicklungsverläufe beim Lesen
Authors: Berendes Karin , Becker Michael , Jacoby Johann , Flunger Barbara , Nagengast Benjamin , Trautwein Ulrich
Published: April 2019

Zusammenfassung. Es ist ein vielfach replizierter Befund, dass Jungen im Durchschnitt über geringere Lesekompetenzen verfügen als Mädchen. Bezogen auf die Entwicklung von Leseleistungen stellt sich allerdings die Frage, ob und wie Unterschiede zwischen den Geschlechtern im Laufe der Sekundarstufe zunehmen, abnehmen oder eher stabil bleiben. Vor allem aus dem englischsprachigen Raum liegen Hinweise dafür vor, dass eine Zunahme der Leistungsunterschiede zwischen Jungen und Mädchen auf Schülerinnen und Schülern mit niedrigem sozioökonomischen Status zurückgeht. Auch der Migrationsstatus und die besuchte Schulform werden als Moderatoren diskutiert. In der vorliegenden Studie wurde den genannten Fragestellungen mit Daten von 2.505 Schülerinnen und Schülern aus Baden-Württemberg nachgegangen. Auf Basis von Daten von vier Testzeitpunkten (5. – 8. Schuljahresstufe) wurden latente Wachstumskurvenmodelle für die Kompetenzbereiche Lesegeschwindigkeit und -verständnis modelliert. Die Ergebnisse zeigen, dass ein Schereneffekt zu Ungunsten der Jungen sowohl in der Lesegeschwindigkeit als auch im Leseverständnis auftrat. Für den sozioökonomischen Status und den Migrationsstatus zeigten sich hingegen keine Schereneffekte der Leseleistungen. Des Weiteren ergaben die Analysen, dass der geschlechterbezogene Schereneffekt nicht durch den sozioökonomischen Status oder den Migrationshintergrund moderiert wird. Die besuchte Schulform stellte sich nicht als bedeutsamer Moderator heraus.
Fluid and Melt Pathways in the Central Chilean Subduction Zone Near the 2010 Maule Earthquake (35–36°S) as Inferred From Magnetotelluric Data
Authors: Cordell Darcy , Unsworth Martyn J. , Diaz Daniel , Reyes‐Wagner Valentina , Currie Claire A. , Hicks Stephen P.
Published: April 2019

The subduction zone of central Chile (36°S) has produced some of the world's largest earthquakes and significant volcanic eruptions. Understanding the fluid fluxes and structure of the subducting slab and overriding plate can provide insight into the tectonic processes responsible for both seismicity and magmatism. Broadband and long‐period magnetotelluric data were collected along a 350‐km profile in central Chile and Argentina and show a regional geoelectric strike of 15 ± 19° east of north. The preferred two‐dimensional inversion model included the geometry of the subducting Nazca plate as a constraint. On the upper surface of the Nazca plate, conductors were interpreted as fluids expelled from the downgoing slab via compaction at shallow depth (C1) and metamorphic reactions at depths of 40–90 km (C2 and C3). At greater depths (130 km), a conductor (C7) is interpreted as a region of partial melt related to deserpentinization in the backarc. A resistor on the slab interface (R1) is coincident with a high‐velocity anomaly which was interpreted as a strong asperity which may affect the coseismic slip behavior of large megathrust earthquakes at this latitude. Correlations with seismicity suggest slab fluids alter the forearc mantle and define the downdip limit of the seismogenic zone. Beneath the volcanic arc, several upper crustal conductors (C4 and C5) represent partial melt beneath the Tatara‐San Pedro Volcano and the Laguna del Maule Volcanic Field. A deeper lower crustal conductor (C6) underlies both volcanoes and suggests a connected network of melt in a thermally mature lower crust.
Nucleation and Kinematic Rupture of the 2017 Mw 8.2 Tehuantepec Earthquake
Authors: Meng Lingsen , Huang Hui , Xie Yuqing , Bao Han , Dominguez Luis A.
Published: April 2019

Integrated observations from the 2017 Mw 8.2 Tehuantepec, Mexico, earthquake probe one of the largest normal‐faulting events inside a subducting slab. In this study, we utilize a template matching approach to detect possible missing earthquakes within a 2‐month period before the mainshock. The seismicity rate shows an abrupt increase in the last day around the mainshock hypocenter. The large distance between most of the foreshocks and the mainshock is not consistent with static stress triggering but suggests alternative mechanisms such as delayed dynamic triggering or aseismic transients. Back‐projection using the USArray network reveals that the rupture propagated northwestward unilaterally at a speed of 3.6 km/s and terminated north of the Tehuantepec Ridge. Towards the end of the rupture, a wide step‐over occurred onto an adjacent fault parallel to the main fault plane. The mainshock is likely a reactivation of subducted outer‐rise faults, supported by the similarity of fault‐strike angles. The surprisingly large magnitude is consistent with exceedingly large dimensions of outer‐rise faulting in this segment of the central Mexican trench.
Fast 4‐D Imaging of Fluid Flow in Rock by High‐Speed Neutron Tomography
Authors: Tudisco E. , Etxegarai M. , Hall S. A. , Charalampidou E.‐M. , Couples G. D. , Lewis H. , Tengattini A. , Kardjilov N.
Published: April 2019

High‐speed neutron tomographies (1‐min acquisition) have been acquired during water invasion into air‐filled samples of both intact and deformed (ex situ) Vosges sandstone. Three‐dimensional volume images have been processed to detect and track the evolution of the waterfront and to calculate full‐field measurement of its speed of advance. The flow process correlates well with known rock properties and is especially sensitive to the distribution of the altered properties associated with observed localized deformation, which is independently characterized by Digital Volume Correlation of X‐ray tomographies acquired before and after the mechanical test. The successful results presented herein open the possibility of in situ analysis of the local evolution of hydraulic properties of rocks due to mechanical deformation.
Weak B‐Type Olivine Fabric Induced by Fast Compaction of Crystal Mush in a Crustal Magma Reservoir
Authors: Yao Zhuosen , Qin Kezhang , Wang Qin , Xue Shengchao
Published: April 2019

Understanding the deformation mechanisms of olivine has been considered as the crucial factor in tracing the dynamic processes from seismic anisotropy. Due to extensive overprinting of deformation and alteration, natural examples of original magmatic fabric of olivine are scarce. In this study we selected one wehrlite and three dunite samples from a deep borehole in the Poyi mafic‐ultramafic intrusion in the Tarim Craton. The fresh samples show adcumulate texture and plastic deformation of dry olivine (≤10 ppm H2O). Thermobarometer calculations yield crystallization conditions at 200–400 MPa and >1,124–1,275 °C. Olivine developed a B‐type fabric characterized by a concentration of [001] axes parallel to the interpreted lineation and that of [010] axes normal to the interpreted foliation. Activation of [001] and [100] dislocations is confirmed by microstructural observations. Simulation of gravity‐driven compaction process reveals extremely rapid compaction of kilometer‐scale crystal mush in the Poyi magmatic system. During the early compaction with high porosity, crystallographic habit of olivine may produce shape‐preferred orientation and the related B‐type fabric. In the final stage of compaction and crystallization, the initial shape‐preferred orientation was gradually overprinted, whereas the weak B‐type fabric has remained with dislocation creep and dislocation‐accommodated grain boundary sliding. Calculated seismic velocities of peridotite samples show low P and S wave anisotropies, with the fastest S wave polarization direction normal to the foliation. Hence, a mush‐dominated ultramafic intrusion exhibits weak seismic anisotropy, which has potential to better understand seismic anisotropy in the transcrustal magmatic systems.
Offshore Landslide Hazard Curves From Mapped Landslide Size Distributions
Authors: Geist Eric L. , ten Brink Uri S.
Published: April 2019

We present a method to calculate landslide hazard curves along offshore margins based on size distributions of submarine landslides. The method utilizes 10 different continental margins that were mapped by high‐resolution multibeam sonar with landslide scar areas measured by a consistent Geographic Information System procedure. Statistical tests of several different probability distribution models indicate that the lognormal model is most appropriate for these siliciclastic environments, consistent with an earlier study of the U.S. Atlantic margin (Chaytor et al., 2009,https://doi.org/10.1016/j.margeo.2008.08.007). Parameter estimation is performed using the maximum likelihood technique, and confidence intervals are determined using likelihood profiles. Pairwise comparison of size distributions for the 10 margins indicates that the U.S. Atlantic and Queen Charlotte margins are different than most other margins. These margins represent end‐members, with the U.S. Atlantic margin having the highest mean scar area and the Queen Charlotte margin the lowest. We demonstrate that empirical, offshore landslide hazard curves can be developed from the landslide size distributions, if the duration of mapped landslide activity is known. This study indicates that the shape parameter of the size distribution is similar among all 10 margins, and thus, the shape of the hazard curves is also similar. Significant differences in hazard curves among the margins are therefore related to differences in mean sizes and, potentially, differences in the duration of landslide activity.
U.S. IOOS Coastal and Ocean Modeling Testbed: Hurricane‐Induced Winds, Waves, and Surge for Deep Ocean, Reef‐Fringed Islands in the Caribbean
Authors: Joyce B. R. , Gonzalez‐Lopez J. , Van der Westhuysen A. J. , Yang D. , Pringle W. J. , Westerink J. J. , Cox A. T.
Published: April 2019

As part of a U.S. Integrated Ocean Observing System (IOOS) funded Coastal and Ocean Modeling Testbed (COMT), hindcasts of waves and storm surge for 2017 Hurricanes Irma and Maria are examined and compared to wave and water level gauge data in the vicinity of Puerto Rico and the U.S. Virgin Islands. The region is characterized by adjacent deep ocean water, narrow shelves, and coral reef systems providing coastal protection. The storm physics are analyzed using an unstructured grid third‐generation wave circulation coupled modeling system (ADCIRC+SWAN) with respect to tides, winds, atmospheric pressure, waves, and wave radiation stress‐induced setup. The water level response is generally dominated by the pressure deficit of the hurricanes. Wind‐driven surge is important over the shallow shelf to the east of Puerto Rico and wave‐induced setup becomes significant at locations in close proximity to the coastline. Contrary to conditions along the Gulf of Mexico shelf, geostrophically induced setup is negligible. Characteristics from a range of meteorological forcing models are assessed, and the associated errors in the hydrodynamic response are quantified. A data‐assimilated tropical planetary boundary model leads to the smallest atmospheric pressure, water level and wave property errors across both storms. Through comparisons between ADCIRC+SWAN and SLOSH‐FW (a structured grid first‐generation wave circulation coupled model), it is shown that the response to atmospheric forcing is similar; however, nearshore wave setup is smaller in SLOSH‐FW due to its coarser resolution here. Further, in addition to erroneous wind‐driven surge through depth limiting over the open ocean, numerical oscillations in the water level time series develop in SLOSH‐FW likely due to its small domain size.
Sensitivity of Midlatitude Heavy Precipitation to SST: A Case Study in the Sea of Japan Area on 9 August 2013
Authors: Iizuka Satoshi , Nakamura Hisashi
Published: April 2019

This study investigates the influence of sea surface temperature (SST) over the Sea of Japan on a heavy precipitation event that occurred over the northern part (Northern Tohoku region) of Japan's largest island on 9 August 2013. Sensitivity experiments with the Weather Research and Forecasting model show that warmer (cooler) SSTs prescribed over the Sea of Japan in the simulations lead to an increase (decrease) in 24‐hr precipitation averaged within the Northern Tohoku region, especially on the Sea of Japan (i.e., windward) side. Though no significant relationship is found between the local maxima and SSTs over the Sea of Japan, those SST values over the Sea of Japan affect the evolution of the intense convective precipitation; higher (lower) SSTs act to shift the location of intense precipitation on the upwind (downwind) side in the present event. The different evolution results in a different interaction with the downstream orography, leading to no significant relationship between the local maxima of intense precipitation and SSTs. The differences arise from the sensitivity of convective updraft to SSTs. The simulations thus suggest that uncertainties in currently available SST products may alter both the area‐averaged precipitation and the geographical locations of intense precipitation, which can potentially impact flash flood and landslide warnings.
Characterizing the Representativity Error of Cloud Profiling Observations for Data Assimilation
Authors: Fielding M. D. , Stiller O.
Published: April 2019

Active observations from profiling instruments such as cloud radar or lidar have proved invaluable in improving our understanding of clouds and their interaction with the atmosphere. However, while they undoubtedly contain a wealth of information about the atmospheric state, the assimilation of such observations into NWP models has so far had mixed success. One reason is the mismatch of scales between the relatively coarse model resolution and the narrow beam‐width of the instruments. To obtain an optimal analysis, this representativity error due to this mismatch in scales must be included within the observation error covariance matrix. In this paper, we demonstrate how a relatively straightforward approach that uses the local variance of the measurement combined with a global estimate of correlation provides a useful estimate of the representativity error. We also show how the method can be used to estimate the correlation in representativity error between observations in both the horizontal and vertical, potentially removing the need to thin the observations, or inflate their observation error. The method is evaluated using 2‐D and 3‐D fields of simulated and observed radar reflectivity before an example application to profiling observations is shown using Cloudsat data.
The Geomorphic Impact of Outburst Floods: Integrating Observations and Numerical Simulations of the 2000 Yigong Flood, Eastern Himalaya
Authors: Turzewski Michael D. , Huntington Katharine W. , LeVeque Randall J.
Published: April 2019

Outburst floods in mountainous landscapes traverse complex topography and interact with the channel and valley walls, producing intense flow hydraulics that drive geomorphic change and impact people and infrastructure. Evidence of modern and ancient outburst floods is scattered around the eastern Himalaya, but hydraulics related to these geomorphic features are uncharacterized, limiting our understanding of the role of large floods in long‐term evolution of the region. Here we combine remote and field observations of the 2000 Yigong River landslide‐dam outburst flood with 2‐D numerical flood simulations using the software GeoClaw. Modeling results agree with field evidence to the extent that we judge the simulated hydraulics to be relevant to flood hazard and geomorphic investigations. Results show that the hydraulics of outburst floods through rugged topography differ from those expected for nonflood flows, in magnitude and in the spatial patterns of flow speed, direction, and shear stress. The flood produced sustained high bed shear stresses capable of plucking meter‐scale blocks immediately downstream of breach, in the steep Tsangpo Gorge, and in isolated locations associated with valley constrictions. Simulated shear stresses suggest that outburst floods deposited numerous kilometer‐scale boulder bars observed along the flood pathway, armoring the bed, increasing channel roughness, and inhibiting incision in locations that would not be predicted for nonflood flows. Our findings highlight the potential for different magnitude flows to promote not only different amounts, but also different patterns of bedrock erosion, with implications for the role of prehistoric megafloods in the topographic evolution of the eastern Himalaya.
A Cloud Top Radiative Cooling Model Coupled With CLUBB in the Community Atmosphere Model: Description and Simulation of Low Clouds
Authors: Guo Zhun , Wang Minghuai , Larson Vincent E. , Zhou Tianjun
Published: April 2019

In this study, a higher‐order closure scheme known as Cloud Layers Unified By Binormals (CLUBB) is coupled with a cloud top radiative cooling scheme (RAD). The cloud top radiative cooling scheme treats the buoyancy flux generated near the top of the boundary layer which helps the CLUBB scheme to better represent the radiation‐turbulence interaction on the condition of coarse vertical resolution. CLUBB with RAD is found to improve subtropical low‐cloud simulations, and the improvement is particularly evident for nocturnal stratocumulus. The improvements are caused by the stronger and more symmetric vertical turbulent mixing in the boundary layer, as CLUBB with RAD increases the variance of vertical velocity and vertical turbulent transports and reduces the skewness of vertical velocity by enhancing the radiative cooling effects and buoyancy fluxes at the cloud layer. The pumping effect related to the stronger vertical turbulent transports further cools and dries the lower boundary layer, which increases the local surface heating fluxes and further improves the low‐cloud simulations.
Reanalysis of Ring Current Electron Phase Space Densities Using Van Allen Probe Observations, Convection Model, and Log‐Normal Kalman Filter
Authors: Aseev N. A. , Shprits Y. Y.
Published: April 2019

Models of ring current electron dynamics unavoidably contain uncertainties in boundary conditions, electric and magnetic fields, electron scattering rates, and plasmapause location. Model errors can accumulate with time and result in significant deviations of model predictions from observations. Data assimilation offers useful tools which can combine physics‐based models and measurements to improve model predictions. In this study, we systematically analyze performance of the Kalman filter applied to a log‐transformed convection model of ring current electrons and Van Allen Probe data. We consider long‐term dynamics of μ = 2.3 MeV/G and K = 0.3 G1/2RE electrons from 1 February 2013 to 16 June 2013. By using synthetic data, we show that the Kalman filter is capable of correcting errors in model predictions associated with uncertainties in electron lifetimes, boundary conditions, and convection electric fields. We demonstrate that reanalysis retains features which cannot be fully reproduced by the convection model such as storm‐time earthward propagation of the electrons down to 2.5 RE. The Kalman filter can adjust model predictions to satellite measurements even in regions where data are not available. We show that the Kalman filter can adjust model predictions in accordance with observations for μ = 0.1, 2.3, and 9.9 MeV/G and constant K = 0.3 G1/2RE electrons. The results of this study demonstrate that data assimilation can improve performance of ring current models, better quantify model uncertainties, and help deeper understand the physics of the ring current particles.