bluuebunny/crossref_metadata_2025 huggingface dataset:
Migración de los jóvenes españoles en redes sociales, de Tuenti a Facebook y de Facebook a Instagram. La segunda migración.
Authors: Marcelino Mercedes Georgina Victoria
Published: July 2015

Los Nativos digitales conviven de manera natural con las nuevas tecnologías y los fenómenos sociales que originan. Constituyen una comunidad virtual flexible y a la vez exigente, demandando redes sociales que presenten contenidos y usos adaptados a su personalidad e intereses, por ello, cuando consideran que una red deja de suplir sus necesidades de interacción, la abandonan. En España se ha suscitado uno de los casos más interesantes de movimiento de usuarios de redes sociales: jóvenes y adolescentes españoles mantuvieron durante algunos años una frecuencia de participación notable en la red social Tuenti, abandonándola progresivamente al trasladarse hacia Facebook, una red similar con notable carácter internacional. Examinando lo acontecido en esa primera situación, podremos obtener información que nos ayude a concretar si nos encontramos ante un segundo movimiento migratorio en el universo virtual de las redes sociales en España, que en esta ocasión parece partir desde Facebook hacia Instagram.--------The Digital Natives naturally coexist with new technologies and the social phenomena it brings. Digital natives are a virtual demanding community, they look for social networks that may contains tools and digital contents according to their personalities, interest and passions, youth and teenagers could leave a social network if the network does not have the features that they need. A interesting case of movement between social networks have happened in Spain; for some years young people actively involved in a national social network for teenagers named Tuenti, later, with the arrived of Facebook to Spain, they left Tuenti and moved to Facebook. We have evaluated this situation for extract information about what caused it, because we think something similar is happening at this time: it seems that Spanish young people are abandoning Facebook and moving to Instagram.
Audiencia social en España: Estrategias de éxito en la televisión nacional
Authors: Saavedra Llamas Marta , Rodríguez Fernández Leticia , Barón Dulce Gemma
Published: July 2015

El presente trabajo de investigación aborda el concepto de audiencia social, nuevo espacio narrativo nacido de la convergencia de la audiencia televisiva y las conversaciones de usuarios en Twitter, analizando las estrategias de los programas de la televisión española con mayor impacto social. Entender qué es exactamente la audiencia social, cómo funciona o qué tipo de mediciones se realizan de la misma se hace más necesario que nunca para ahondar en los usos y oportunidades que supone tanto para el medio televisivo como para los anunciantes, que deciden invertir en un espacio determinado. A través del estudio de casos exitosos ya implantados se pretende establecer fórmulas de éxito que logren una participación aún más activa de los usuarios, el trasvase de audiencia social a la audiencia tradicional y la inclusión ventajosa de las marcas en este nuevo escenario comunicacional cargado de posibilidades.
Solidaridad en la redes sociales: cuando el usuario abandona su zona de confort - el caso de Charlie Hebdo’
Authors: Herrera-Viedma Enrique , Bernabé-Moreno Juan , Porcel Gallego Carlos , Martínez Sánchez María de los Ángeles
Published: July 2015

Las nuevas generaciones se sienten como en casa en las redes sociales. El miedo a compartir información en estas plataformas brilla por su ausencia. El comportamiento de cada uno es muy homogéneo dentro de su propia comunidad, siguiento patrones muy claros y definidos. Cuando un evento trágico sacude los corazones de los usuarios, la necesidad de romper esos patrones para comunicar sus sentimientos a una audiencia mayor se impone. En este trabajo, analizamos este fenómeno, identificando los cambios en la comunicación en el transcurso del tiempo así como nuevos patrones. Para ilustrar nuestro análisis, nos basamos en un caso real, el atentado contra la redacción de Charlie Hebdo en París.
La mémoire de la tradition spectaculaire dans le théâtre québécois
Authors: Guay Hervé
Published: July 2015

L’auteur s’emploie dans cet article à appliquer à la scène québécoise le concept de ghosting, emprunté à Herbert Blau puis étendu par Marvin Carlson à l’ensemble de l’activité théâtrale, en repérant un peu partout dans cette tradition spectaculaire des traces du phénomène. Cette présence fantomatique de la tradition est d’abord décelable dans les textes, le plus souvent sur un mode parodique, ensuite dans le jeu des acteurs, avec tous les risques que cela comporte dans un petit marché comme le Québec, puis par la citation de productions célèbres ou de leurs propres spectacles par certains metteurs en scène. L’article se termine par un examen des lieux hantés par la présence fantomatique d’artistes de la scène, nouvelle preuve de la capacité du théâtre québécois de transmettre par des moyens proprement scéniques une mémoire de sa tradition.
Denis Marleau met en scène Othello : une oeuvre de répertoire dans le « contre-répertoire » d’UBU
Authors: Siaud Florent
Published: July 2015

Réputé pour son exploration des avant-gardes historiques, ses adaptations de récits ou son goût pour les créations, Denis Marleau a constitué au fil de l’histoire de sa compagnie de création Ubu un répertoire iconoclaste dans les marges du grand répertoire institutionnel. Durant l’automne 2007, il délaisse provisoirement les chemins inexplorés de la transposition générique ou des oeuvres rares pour aborder Othello de Shakespeare au Centre national des Arts d’Ottawa puis à l’Usine C de Montréal. Confrontation d’une pièce canonique avec un répertoire individuel à l’identité fortement marquée, cette rencontre a débouché sur un processus de mise à nu radical.
LXRs link metabolism to inflammation through Abca1-dependent regulation of membrane composition and TLR signaling
Authors: Ito Ayaka , Hong Cynthia , Rong Xin , Zhu Xuewei , Tarling Elizabeth J , Hedde Per Niklas , Gratton Enrico , Parks John , Tontonoz Peter
Published: July 2015

The liver X receptors (LXRs) are transcriptional regulators of lipid homeostasis that also have potent anti-inflammatory effects. The molecular basis for their anti-inflammatory effects is incompletely understood, but has been proposed to involve the indirect tethering of LXRs to inflammatory gene promoters. Here we demonstrate that the ability of LXRs to repress inflammatory gene expression in cells and mice derives primarily from their ability to regulate lipid metabolism through transcriptional activation and can occur in the absence of SUMOylation. Moreover, we identify the putative lipid transporter Abca1 as a critical mediator of LXR's anti-inflammatory effects. Activation of LXR inhibits signaling from TLRs 2, 4 and 9 to their downstream NF-κB and MAPK effectors through Abca1-dependent changes in membrane lipid organization that disrupt the recruitment of MyD88 and TRAF6. These data suggest that a common mechanism-direct transcriptional activation-underlies the dual biological functions of LXRs in metabolism and inflammation.
Performances de autopresentación a través de fotografías digitales. El caso de los adolescentes de sectores populares en Facebook
Authors:   Universidad de Buenos Aires, Buenos Aires, Argentina, Linne Joaquín , Basile Diego ,   Universidad de Buenos Aires, Buenos Aires, Argentina
Published: July 2015

Este artículo aborda el tema de las fotografías personales que producen y publican en la plataforma Facebook los adolescentes de sectores populares de la ciudad de Buenos Aires. La metodología es cualitativa y consiste en un análisis de contenido de perfiles de Facebook (n: 200). La hipótesis es que estos adolescentes utilizan cotidianamente estas herramientas comunicacionales comunicativas para autopresentarse en Facebook ante los otros. Entre los resultados, se destaca que las fotos que más importancia tienen para los adolescentes de esta población son las fotos de sí mismos y las que los muestran con sus grupos de pares. A su vez, se proponen tres categorías para clasificar las fotos personales que publican en red: “autofotos”, “foto-book” y “foto con grupo de pares”.
Análisis del uso e interacción con aplicaciones second screen en TV Social en España
Authors:   Universidad Pontificia de Salamanca. Salamanca, España, Galindo Rubio| Fernando , Fernández Blanco Elena ,   Universidad Pontificia de Salamanca. Salamanca, España, Alameda García David ,   Universidad Pontificia de Salamanca. Salamanca, España
Published: July 2015

En este artículo se aborda la situación actual de las aplicaciones second screen en España, fenómeno destinado a la interacción con la Televisión Social a través de smartphones. Para ello se realiza un mapa de dicha actividad con referencia a las tres formas de interacción principales: redes sociales convencionales, aplicaciones aglutinadoras de contenido y aplicaciones second screen. Valorar el conocimiento que de tales aplicaciones se tiene, y su eficacia, será el objetivo de este trabajo, el cual ha sido desarrollado a partir de una investigación con metodologías mixtas cuantitativas y cualitativas, centrada en el análisis de la forma en que los usuarios utilizan las aplicaciones second screen e interactúan con ellas. La incorrecta configuración del valor añadido que ofrecen las aplicaciones existentes se presenta como el principal de los resultados de la investigación, y lleva a que este trabajo sea redactado con la vocación de ser útil para una revisión de la configuración de dicho aporte añadido, y como apoyo en el diseño y estructuración de futuras aplicaciones.
Comunicación en el Plan Nacional de Educación en Brasil: un enfoque crítico
Authors:   FAPP-UEMG, Belo Horizonte, Brasil, Alvarenga Camila , de Aquino Rafael Luiz ,   FAPP-UEMG, Belo Horizonte, Brasil, Marcio Barros Jose ,   FAPP-UEMG e PUC Minas, Belo Horizonte, Brasil, Braga Ribeiro Núbia ,   FAPP-UEMG, Belo Horizonte, Brasil
Published: July 2015

Este trabalho busca refletir sobre o tratamento que o atual Plano Nacional de Educação no Brasil (PNE 2014-2024) dá à questão da comunicação. A partir dos conceitos de educomunicação e ecossistema comunicativo o texto, em sua primeira parte, busca estabelecer uma relação conceitual entre comunicação e educação. Na segunda parte são apresentados os dois últimos PNE brasileiros (2001-2010 e 2014- 2024), de modo a subsidiar a análise de como nas metas e estratégias de ambos a questão da comunicação é abordada. Foi possível perceber como a tradicional postura de negação da complexidade das transformações culturais da atualidade e a recusa das instituições em tratar o que efetivamente é vivido pelos diversos atores envolvidos no processo de educação contribuem para que a comunicação ainda seja vista como uma dimensão secundária e por um viés instrumental.
El radioteatro como herramienta educativa para promover el patrimonio inmaterial: hombres y mujeres del mar en el sur de Chile
Authors:   Universidad de Chile, Rodríguez Ortiz Raúl
Published: July 2015

El radioteatro es un género apropiado para aportar a la memoria sonora, a la promoción y a la transmisión del patrimonio inmaterial. De allí la importancia de indagar sobre la relación entre la radio, la educación y la cultura. En esa línea, este artículo da cuenta de dos experiencias de radioteatro, con textos basados en el saber ancestral de los constructores de lancha tradicional y de las mariscadoras del sur de Chile, ambos de la comuna de Hualaihué, región de Los Lagos. A partir de una metodología cualitativa, se recogieron testimonios de estos hombres y mujeres del mar, y se registraron sonidos naturales de sus oficios y de la localidad, como base para la elaboración de las dos piezas de radioteatro, cuya transmisión fue hecha para la región por la emisora con mayor sintonía local. De esta forma se combinaron ficción y realidad para recrear historias populares, formas de vida y sonoridad del pueblo. La iniciativa permitió así a las comunidades apropiarse de estos bienes culturales a través de una experiencia de enseñanza no tradicional.
Un estudio de la homogeneidad entre las posturas editoriales y de las fuentes informativas en la prensa de referencia chilena
Authors:   Pontificia Universidad Católica de Chile, Gronemeyer María Elena , Porath William ,   Pontificia Universidad Católica de Chile
Published: July 2015

Se espera del periodismo que nutra la democracia a través de la aportación de contenidos públicos relevantes. La capacidad de la ciudadanía para discutir asuntos de importancia social depende de la disponibilidad de ideas, opiniones y antecedentes factuales que contribuyan a conocer y dar sentido a la contingencia desde las más variadas perspectivas posibles. Teniendo en cuenta que se califica a la concentración de la propiedad de la prensa en Chile de emblemática, el objetivo de este trabajo es analizar sistemáticamente diarios de referencia chilenos, para establecer si las empresas de El Mercurio SAP y Copesa SA constituyen un duopolio ideológico que atenta contra el objetivo democrático del periodismo. Metodológicamente, se trata de un análisis de contenido comparativo de posturas adoptadas en editoriales y noticias en cinco periódicos para determinar si estos medios tienden a seleccionar fuentes informativas que coincidan con sus puntos de vista. Este revela que en Chile no se puede sostener de manera general o sistemática la hipótesis de una homogeneidad intra-medios. Sin embargo, los diarios analizados tendían hacia un comportamiento similar en términos de homogeneidad intra-medios, por cuanto tienden a comportarse de una manera parecida.
Derribando el autoestigma: medios de comunicación en prisiones como aliados de la inclusión social
Authors:   Universidad de Huelva, Huelva, España, Contreras Pulido Paloma , Martín Pena Daniel ,   Universidad de Extremadura, Badajoz, España, Aguaded Gómez José Ignacio ,   Universidad de Huelva, Huelva, España
Published: July 2015

La producción de medios de comunicación dentro de prisiones puede llegar a ser una aliada importante para la inclusión social de los presos. Este estudio indaga sobre estas iniciativas en España. A pesar de que los esfuerzos de alfabetización mediática como herramientas de intervención en las prisiones siguen siendo invisibles para la gran mayoría de la sociedad, e incluso para las propias instituciones penitenciarias, se han contabilizado 39 experiencias diferentes en el contexto español. A través de una metodología cualitativa basada en entrevistas en profundidad con 29 presos y 6 educadores que participan en estos proyectos en cárceles españolas, se concluye que este tipo de actividades ayuda a derribar estigmas y –aún más importante– autoestigmas. Sin pretender ser representativos, los resultados demuestran que estas actividades pueden llegar a ser una valiosa herramienta de inserción socioeducativa y de transformación personal.
Triplemente marcadas: desconexiones comunicativas en la Amazonía sur ecuatoriana
Authors:   Universidad de Cuenca, Cuenca, Ecuador, Martínez Suárez Yolanda , de Salvador Agra Saleta ,   Universidad de Cuenca, Cuenca, Ecuador, de Salvador González Xabier ,   Universidad de la Coruña, La Coruña, España
Published: July 2015

En el siglo XXI, en la era móvil, cabe revisitar la tesis del aislamiento exclusivo de las zonas remotas, o “de acceso particularmente difícil” enunciada en el Informe MacBride en los ochenta. El objetivo de la presente investigación es ofrecer una radiografía de las desconexiones y desigualdades sufridas en un contexto tecnológicamente remoto, en la Amazonía sur ecuatoriana. Para llevar a cabo tal estudio usamos una metodología cuantitativa. Considerando las variables de género, etnia indígena (shuar y kichwa-saraguro) y no indígena, y edad, emprendimos un análisis de la penetración de la tecnología móvil (desde la brecha de acceso, desglosada en la propiedad de los dispositivos, el acceso mediante préstamo y la cobertura), del consumo cultural de los medios tradicionales (TV, radio, periódicos y revistas), hasta Internet. Los resultados apuntan no solo a una discriminación sumativa, sino a una clara interacción o efecto multiplicativo entre las variables de estudio (género, etnia y generación).
Professional development in teacher digital competence and improving school quality from the teachers’ perspective: a case study
Authors: Gisbert Cervera Mercè , Lázaro Cantabrana José L.
Published: July 2015

Professional development in ICT for teachers, in addition to being necessary given the dynamic nature of technology, also improves the institutional quality of schools. This work, based on action research, provides evidence that the school itself is capable of organising and designing a training plan as part of a broader process to improve quality based on the incorporation of ICT. In turn, it addresses the pivotal elements of a training strategy that facilitates the transfer of that strategy to classroom activities and increases the quality of the school as an institution.
Introducing Shared Mental Health Care in Northwestern Ontario: An Analysis of Changing Referral Patterns of Primary Care Providers
Authors: Gaylord Graham , Bailey S. Kathleen , Haggarty John M.
Published: July 2015

This study describes a shared mental health care (SMHC) model introduced in Northern Ontario and examines how its introduction affected primary care provider (PCP) mental health referral patterns. A chart review examined referrals (N = 4,600) from 5 PCP sites to 5 outpatient community mental health services from January 2001 to December 2005. PCPs with access to SMHC made significantly more mental health referrals (p < 0.001). Two demographically similar PCPs were then compared, one co-located with SMHC. Referrals for depression to non-SMHC mental health services were 1.69 times more likely to be from the PCP not co-located with SMHC (p < 0.001). Findings suggest SMHC increases access to care and decreases demand on existing mental health services.
Windows of opportunity for salt marsh vegetation establishment on bare tidal flats: The importance of temporal and spatial variability in hydrodynamic forcing
Authors: Hu Zhan , van Belzen Jim , van der Wal Daphne , Balke Thorsten , Wang Zheng Bing , Stive Marcel , Bouma Tjeerd J.
Published: July 2015

Understanding the mechanisms limiting and facilitating salt marsh vegetation initial establishment is of widespread importance due to the many valuable services salt marsh ecosystems offer. Salt marsh dynamics have been investigated by many previous studies, but the mechanisms that enable or disable salt marsh initial establishment are still understudied. Recently, the “windows of opportunity” (WoO) concept has been proposed as a framework providing an explanation for the initial establishment of biogeomorphic ecosystems and the role of physical disturbance herein. A WoO is a sufficiently long disturbance‐free period following seedling dispersal, which enables successful establishment. By quantifying the occurrence of WoO, vegetation establishment pattern can be predicted. For simplicity sake and as prove of concept, the original WoO framework considers tidal inundation as the only physical disturbance to salt marsh establishment, whereas the known disturbance from tidal currents and wind waves is ignored. In this study, we incorporate hydrodynamic forcing in the WoO framework. Its spatial and temporal variability is considered explicitly in a salt marsh establishment model. We used this model to explain the observed episodic salt marsh recruitment in the Westerschelde Estuary, Netherlands. Our results reveal that this model can significantly increase the spatial prediction accuracy of salt marsh establishment compared to a model that excludes the hydrodynamic disturbance. Using the better performing model, we further illustrate how tidal flat morphology determines salt marsh establishing elevation and width via hydrodynamic force distribution. Our model thus offers a valuable tool to understand and predict bottlenecks of salt marsh restoration and consequences of changing environmental conditions due to climate change.
Profiling planktonic foraminiferal crust formation
Authors: Steinhardt Juliane , de Nooijer Lennart L. J. , Brummer Geert‐Jan , Reichart Gert‐Jan
Published: July 2015

Planktonic foraminifera migrate vertically through the water column during their life, thereby growing and calcifying over a range of depth‐associated conditions. Some species form a calcite veneer, crust, or cortex at the end of their lifecycle. This additional calcite layer may vary in structure, composition, and thickness, potentially accounting for most of their total shell mass and thereby dominating the element and isotope signature of the whole shell. Here we apply laser ablation ICP‐MS depth profiling to assess variability in thickness and Mg/Ca composition of shell walls of three encrusting species derived from sediment traps. Compositionally, Mg/Ca is significantly lower in the crusts of Neogloboquadrina dutertrei and Globorotalia scitula, as well as in the cortex of Pulleniatina obliquiloculata, independent of the species‐specific Mg/Ca of their lamellar calcite shell. Wall thickness accounts for nearly half of the total thickness in both crustal species and nearly a third in cortical P. obliquiloculata, regardless of their initial shell wall thickness. Crust thickness and crustal Mg/Ca decreases toward the younger chambers in N. dutertrei and to a lesser extent, also in G. scitula. In contrast, the cortex of P. obliquiloculata shows a nearly constant thickness and uniform Mg/Ca through the complete chamber wall. Patterns in thickness and Mg/Ca of the crust indicate that temperature is not the dominant factor controlling crust formation. Instead, we present a depth‐resolved model explaining compositional differences within individuals and between successive chambers as well as compositional heterogeneity of the crust and lamellar calcite in all three species studied here.
Effects of chemical composition, water and temperature on physical properties of continental crust
Authors: Guerri Mattia , Cammarano Fabio , Connolly James A. D.
Published: July 2015

We explore the influence of major elements chemistry and H2O‐content on the density and seismic velocity of crustal rocks by computing stable and metastable crustal mineralogy and elastic properties as a function of pressure and temperature (P‐T). Proposed average compositions of continental crust result in significantly different properties, for example a difference in computed density of ∼ 4 % is obtained at a given P‐T. Phase transformations affect crustal properties at the point that crustal seismic discontinuities can be explained with mineral reactions rather than chemical stratification. H2O, even if introduced in small amount in the chemical system, has an effect on physical properties comparable to that attributed to variations in major elements composition. Thermodynamical relationships between physical properties differ significantly from commonly used empirical relationships. Density models obtained by inverting CRUST 1.0 compressional wave velocity are different from CRUST 1.0 density and translate into variations in isostatic topography and gravitational field that ranges ±600 m and ±150 mGal respectively. Inferred temperatures are higher than reference geotherms in the upper crust and in the deeper portions of thick orogenic crust, consistently with presence of metastable rocks. Our results highlight interconnections/dependencies among chemistry, pressure, temperature, seismic velocities and density that need to be addressed to better understand the crustal thermo‐chemical state.
The Manihiki Plateau—A multistage volcanic emplacement history
Authors: Pietsch Ricarda , Uenzelmann‐Neben Gabriele
Published: July 2015

The formation history of the Manihiki Plateau, a Large Igneous Province, is poorly understood. New high‐resolution seismic reflection data across the High Plateau, the largest edifice of the Manihiki Plateau, provide evidence for multistage magmatic emplacement. Improved data quality allows for an identification of an earlier volcanic phase, the initial formation phase (>125 Ma), in addition to the previously known volcanic formation phases: the expansion phase (125–116) formerly called main‐phase, and the secondary volcanic phase (100–65 Ma). This enhances the understanding of the emplacement scenario. An intrabasement reflection band IB1 reveals the end of initial volcanic formation and forms the nucleus of the High Plateau. This feature provides indications that it continued beyond the Manihiki Scarp and thus supports the hypothesis of an extension of the Manihiki Plateau to the East during the initial formation and expansion phases. The expansion phase is characterized by massive volcanic outpourings leveling and extending the basement throughout the High Plateau and the neighboring Western Plateaus, which in contrast shows massive tectonic alteration. Extrusion centers formed within the secondary volcanic phase (ending ∼65 Ma) are mainly concentrated along the margins of the High Plateau, suggesting the magmatic sources shifted from those being related to the initial emplacement and expansion phases of the High Plateau to induced volcanism at the tectonically altered margins.
Tsunamis from the 29 March and 5 May 2015 Papua New Guinea earthquake doublet (Mw7.5) and tsunamigenic potential of the New Britain trench
Authors: Heidarzadeh Mohammad , Gusman Aditya Riadi , Harada Tomoya , Satake Kenji
Published: July 2015

We characterized tsunamis from the 29 March and 5 May 2015 Kokopo, Papua New Guinea,Mw7.5 earthquake doublet. Teleseismic body wave inversions using various rupture velocities (Vr) showed similar source‐time functions and waveform agreements, but the spatial distributions of the slips were different. The rupture durations were ~45 and ~55 s for the March and May events, with their peaks at ~25 and at ~17 s, respectively. Tsunami simulations favored source models withVr = 1.75 and 1.50 km/s for the March and May earthquakes. The largest slip on the fault was similar (2.1 and 1.7 m), but the different depths and locations yielded maximum seafloor uplift of ~0.4 and ~0.2 m. Tsunami simulation from hypothetical great earthquakes (M8.4 and 8.5) on the New Britain trench showed that tsunami amplitudes may reach up to 10 m in Rabaul, but most tsunami energy was confined within the Solomon Sea.
The 2013 Balochistan earthquake: An extraordinary or completely ordinary event?
Authors: Zhou Yu , Elliott John R. , Parsons Barry , Walker Richard T.
Published: July 2015

The 2013 Balochistan earthquake, a predominantly strike‐slip event, occurred on the arcuate Hoshab fault in the eastern Makran linking an area of mainly left‐lateral shear in the east to one of shortening in the west. The difficulty of reconciling predominantly strike‐slip motion with this shortening has led to a wide range of unconventional kinematic and dynamic models. Here we determine the vertical component of motion on the fault using a 1 m resolution elevation model derived from postearthquake Pleiades satellite imagery. We find a constant local ratio of vertical to horizontal slip through multiple past earthquakes, suggesting the kinematic style of the Hoshab fault has remained constant throughout the late Quaternary. We also find evidence for active faulting on a series of nearby, subparallel faults, showing that failure in large, distributed and rare earthquakes is the likely method of faulting across the eastern Makran, reconciling geodetic and long‐term records of strain accumulation.
Tail shortening with developing eddies in a rough‐walled rock fracture
Authors: Lee Seung Hyun , Yeo In Wook , Lee Kang‐Kun , Detwiler Russell L.
Published: July 2015

Understanding fluid flow and solute transport in rough‐walled fractures is important in many problems such as geological storage of CO2 and siting of radioactive waste repositories. The first microscopic observation of fluid flow and solute transport through a rough‐walled fracture was made to assess the evolution of eddies and their effect on non‐Fickian tailing. A noteworthy phenomenon was observed that as the eddy grew, the particles were initially caught in and swirled around within eddies, and then cast back into main flow channel, which reduced tailing. This differs from the conventional conceptual model, which presumes a distinct separation between mobile and immobile zones. Fluid flow and solute transport modeling within the 3‐D fracture confirmed tail shortening due to mass transfer by advective paths between the eddies and the main flow channel, as opposed to previous 2‐D numerical studies that showed increased tailing with growing eddies.
Statistical characteristics of slow earthward and tailward flows in the plasma sheet
Authors: Zhang L. Q. , Baumjohann W. , Wang J. Y. , Rème H. , Dunlop M. W. , Chen T.
Published: July 2015

In this paper, we statistically analyzed and compared the earthward flow (EF) and the tailward flow (TF) in the plasma sheet. It is found that the properties of the EF/TF in the central plasma sheet (CPS) of β > 1 and the outer plasma sheet (OPS) of 0.1 < β < 1 are distinctly different. The main conclusions include that (1) the EFs occur in both the CPS and the OPS while the TFs mainly occur in the OPS, (2) both flows are dominantly convective in the CPS and parallel in the OPS, (3) in the CPS, the EF and the TF have similar characteristics, including their bulk velocities and ion densities and Ey components. Both flows tend to have isotropic temperatures; (4) in the OPS, the EFs tend to have higher ion velocity, density, and Ey than the TF. The EFs tend to have anisotropic temperatures, while the TFs tend to have more isotropic temperatures. As a whole, combined characteristics of the EF and the TF are consistent with (1) reflection at the “magnetic mirror point” near the Earth for parallel flows in the OPS and (2) bouncing off/back from the dipolar field closer to the Earth for convective flows in the CPS.
Slow and Go: Pulsing slip rates on the creeping section of the San Andreas Fault
Authors: Turner Ryan C. , Shirzaei Manoochehr , Nadeau Robert M. , Bürgmann Roland
Published: July 2015

Rising and falling slip rates on the creeping section of the San Andreas Fault have been inferred from variations of recurrence intervals of characteristically repeating microearthquakes, but this observation has not previously been confirmed using modern geodetic data. Here we report on observations of this “pulsing” slip obtained from advanced multitemporal interferometric synthetic aperture radar (InSAR) data, confirmed using continuous GPS sites of the Plate Boundary Observatory. The surface deformation time series show a strong correlation to the previously documented slip rate variations derived from repeating earthquakes on the fault interface, at various spatial and temporal scales. Time series and spectral analyses of repeating earthquake and InSAR data reveal a quasiperiodic pulsing with a roughly 2 year period along some sections of the fault, with the earthquakes on the fault interface lagging behind the far‐field deformation by about 6 months. This suggests a temporal delay between the pulsing crustal strain generated by deep‐seated shear and the time‐variable slip on the shallow fault interface, and that at least in some places this process may be cyclical. There exist potential impacts for time‐dependent seismic hazard forecasting in California and, as it becomes better validated in the richly instrumented natural laboratory of the central San Andreas Fault, the process used here will be even more helpful in characterizing hazard and fault zone rheology in areas without California's geodetic infrastructure.
Some aspects of the Coriolis‐Stokes forcing in the oceanic momentum and energy budgets
Authors: Weber Jan Erik H. , Drivdal Magnus , Christensen Kai H. , Broström Göran
Published: July 2015

The Coriolis‐Stokes (CS) force is a wave‐induced forcing of the Eulerian mean motion in a rotating ocean. For idealized conditions, it is demonstrated by comparison with Lagrangian results that the appropriate surface boundary condition for the Eulerian mean wave‐induced flow is that of vanishing vertical shear. The Eulerian mean current derived by applying this condition plus the inviscid Stokes drift yield the Lagrangian wave‐induced drift velocity, apart from a small boundary‐layer correction. Appreciation of the importance of the CS force in the momentum balance has led to investigations of the role of the CS force in the energy budget. The present study shows that the CS force is not a source for the rate of change of the total average energy density in the fluid, when the vertical integration is performed to the moving material surface. However, results to fourth order in wave steepness confirm earlier findings that the CS force acts to change the vertically integrated Eulerian kinetic energy of the mean flow. A new interpretation relates this effect to the fact that the mean Eulerian Coriolis force performs work in acting along the motion of the Lagrangian wave‐induced mass (caused by the divergence effect) at the surface.
Winter‐to‐summer precipitation phasing in southwestern North America: A multicentury perspective from paleoclimatic model‐data comparisons
Authors: Coats Sloan , Smerdon Jason E. , Seager Richard , Griffin Daniel , Cook Benjamin I.
Published: July 2015

The phasing of winter‐to‐summer precipitation anomalies in the North American monsoon (NAM) region 2 (113.25°W–107.75°W, 30°N–35.25°N—NAM2) of southwestern North America is analyzed in fully coupled simulations of the Last Millennium and compared to tree ring reconstructed winter and summer precipitation variability. The models simulate periods with in‐phase seasonal precipitation anomalies, but the strength of this relationship is variable on multidecadal time scales, behavior that is also exhibited by the reconstructions. The models, however, are unable to simulate periods with consistently out‐of‐phase winter‐to‐summer precipitation anomalies as observed in the latter part of the instrumental interval. The periods with predominantly in‐phase winter‐to‐summer precipitation anomalies in the models are significant against randomness, and while this result is suggestive of a potential for dual‐season drought on interannual and longer time scales, models do not consistently exhibit the persistent dual‐season drought seen in the dendroclimatic reconstructions. These collective findings indicate that model‐derived drought risk assessments may underestimate the potential for dual‐season drought in 21st century projections of hydroclimate in the American Southwest and parts of Mexico.
Observations of positive narrow bipolar pulses
Authors: Karunarathne Sumedhe , Marshall Thomas C. , Stolzenburg Maribeth , Karunarathna Nadeeka
Published: July 2015

Waveforms of 226 positive narrow bipolar pulses (NBPs) were obtained with five to eight stations of E‐change meters covering an area of 70 × 100 km2. The NBPs had typical average parameters: 10–90% rise time of 2.6 μs, full width at half maximum time of 2.8 μs, zero cross time of 9.9 μs, and range‐normalized amplitude at 100 km of 11.0 V/m. Four main types of positive NBP waveforms were identified: Type A had a simple bipolar waveform with a positive peak and a negative overshoot peak (1% of NBPs), Type B had extra peak(s) superimposed on the overshoot peak (67%), Type C had extra peak(s) on or just after the main positive peak (13%), and Type D had extra peak(s) before the main positive peak (19%). Regardless of type, each NBP waveform maintained its basic shape across a range of 10 to 130 km from its origin. NBP locations, obtained with a time of arrival technique, seemed unrestricted in their horizontal distribution (except for Type C), while NBP altitudes ranged from 7 to 19 km with an average of 13 km. Estimated peak currents were 2–126 kA with an average of 30 kA. Isolation of NBPs from other lightning events was determined for both temporal (660 ms) and spatial (>10 km) quantities; 37% of NBPs were isolated, 38% occurred within 660 ms before a flash, 19% occurred within flashes, and 11% occurred within 660 ms after a flash. The total RMS power radiated by NBPs within 1 kHz–2.5 MHz bandwidth had a range of 5.0 × 106–6.1 × 108 W with an average of 7.8 × 107 W.
Increasing evaporation amounts seen in the Arctic between 2003 and 2013 from AIRS data
Authors: Boisvert L. N. , Wu D. L. , Shie C.‐L.
Published: July 2015

The vertical moisture flux (i.e., evaporation) plays an important role in the Arctic energy budget, the water vapor feedback, and Arctic amplification. It is one of the most uncertain variables, especially in this “new Arctic” climate system, which is dominated by large ice‐free ocean areas for a longer portion of the year. Moisture flux rates, produced using Atmospheric Infrared Sounder (AIRS) data, from the Arctic Ocean and surrounding seas were found to have increased between 2003 and 2013 by 7.2 × 10−4 g m−2 s−1 per year (equivalent to 1.79 W m−2 per year in latent heat). This is a 7% increase in the average moisture flux each year and a 0.12% increase in the yearly global ocean latent heat flux, with some months increasing more than others. The largest increases seen are in the Arctic coastal seas during the spring and fall where there has been a reduction in sea ice cover and an increase in sea surface temperatures. Increases in the moisture flux from the surface also correspond to increases in total atmospheric column water vapor and low‐level clouds, especially in the central Arctic regions. Changes in the atmospheric water vapor in the surrounding seas (e.g., East Greenland) are most likely due to lower latitude transport of moisture rather than from the surface. Yearly, the moisture flux from the surface supplies about 10% of the total column atmosphere water vapor.
Cold air incursions, δ18O variability, and monsoon dynamics associated with snow days at Quelccaya Ice Cap, Peru
Authors: Hurley John V. , Vuille Mathias , Hardy Douglas R. , Burns Stephen J. , Thompson Lonnie G.
Published: July 2015

Quelccaya Ice Cap in the Andes of Peru contains an annually resolved δ18O record covering the past 1800 years; yet atmospheric dynamics associated with snow deposition and δ18O variability at this site are poorly understood. Here we make use of 10 years of snow pit and short core δ18O data and hourly snow‐height measurements obtained by an automated weather station deployed at the ice cap's summit to analyze linkages between snowfall, δ18O, and the South American summer monsoon (SASM). Snow accumulation peaks in December and is negative May–September. Snow δ18O values decrease gradually through austral summer from about −17 to −24‰. Surface snow δ18O is altered after deposition during austral winter from about −24 to −15‰. More than 70% of the total snow accumulation is tied to convection along the leading edge of cold air incursions of midlatitude air advected equatorward from southern South America. Snowfall amplitude at Quelccaya Ice Cap varies systematically with regional precipitation, atmospheric dynamics, midtroposphere humidity, and water vapor δD. Strongest snowfall gains correspond with positive precipitation anomalies over the western Amazon Basin, increased humidity, and lowered water vapor δD values, consistent with the “amount effect.” We discuss ventilation of the monsoon, modulated by midlatitude cold air advection, as potentially diagnostic of the relationship between SASM dynamics and Quelccaya snowfall. Results will serve as a basis for development of a comprehensive isotopic forward model to reconstruct past monsoon dynamics using the ice core δ18O record.
Vibrational‐vibrational and vibrational‐thermal energy transfers of CO2 with N2 from MIPAS high‐resolution limb spectra
Authors: Jurado‐Navarro Á. A. , López‐Puertas M. , Funke B. , García‐Comas M. , Gardini A. , Stiller G. P. , Clarmann T. von
Published: July 2015

We present a retrieval of several vibrational‐vibrational (V V) and vibrational‐thermal (V‐T) collisional rate coefficients affecting the populations of the CO2 levels emitting at 10, 4.3 and 2.7 μm from high‐resolution limb atmospheric spectra taken by Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). This instrument has a high spectral resolution (0.0625 cm−1) and a wide spectral coverage (from 685 to 2410 cm−1) that allow measuring and discriminating among the many bands originating the atmospheric 4.3 μm radiance. Also its high sensitivity allows measuring the atmospheric limb emission in a wide altitude range, from 20 to 170 km in its middle and upper atmosphere modes, and hence obtain information on the temperature dependence of the collisional rates. In particular, we retrieve the rate coefficients and their temperature dependence in the 130–250 K range of the following processes: with vd=2v1+v2=2,3, and 4; with and Δl = 0; and with Δvd=0 and Δl ≠ 0. In addition we have also retrieved the thermal relaxation of CO2(v3) into the v1 and v2 modes, e.g., with Δvd=2–4 and Δv3=−1 and the efficiency of the excitation of N2(1) by O(1D). All of them were retrieved with a much better accuracy than were known before. The new rates have very important effects on the atmospheric limb radiance in the 10, 4.3 and 2.7 μm spectral regions (5–8% at 4.3 μm) and allow a more accurate inversion of the CO2 volume mixing ratio in the mesosphere and lower thermosphere from measurements taken in those spectral regions.
Reconstructing a sediment pulse: Modeling the effect of placer mining on Fraser River, Canada
Authors: Ferguson R. I. , Church M. , Rennie C. D. , Venditti J. G.
Published: July 2015

Gold mining along 525 km of the Fraser River between 1858 and 1909 added an estimated 1.1 × 108 t of tailings, half gravel and the rest finer, to the river's natural sediment load. We simulate the response using a 1‐D multigrain size morphodynamic model. Since premining conditions are unknown and modern data are insufficient for tuning the process representation, we devised a novel modeling strategy which may be useful in other data‐poor applications. We start the model from a smoothed version of the modern longitudinal profile with bed grain size distributions optimized to match alternative assumptions about natural sediment supply and compare runs that include mining with control runs that can be used to quantify the effects of deficiencies in process representation and initialization. Simulations with an appropriate choice of natural supply rate closely match the best available test data, which consist of a detailed 1952–1999 gravel budget for the distal part of the model domain. The simulations suggest that the main response to mining was rapid bed fining, which allowed a major increase in bed load transport rate with only slight (~0.1 m) mean aggradation within the mining region and most of the excess sediment exported well beyond the mountain front within the mining period or soon afterward. We compare this pattern of response by a large, powerful river with previous case studies of river adjustment to sediment supply change.
Variability of rock erodibility in bedrock‐floored stream channels based on abrasion mill experiments
Authors: Small Eric E. , Blom Tevis , Hancock Gregory S. , Hynek Brian M. , Wobus Cameron W.
Published: July 2015

We quantify variations in rock erodibility, Kr, within channel cross sections using laboratory abrasion mill experiments on bedrock surfaces extracted from streams with sandstone bedrock in Utah and basaltic bedrock in the Hawaiian Islands. Samples were taken from the thalweg and channel margins, the latter at a height that is inundated annually. For each sample, a sequence of abrasion mill experiments was completed to quantify variations in erosion rate with erosion depth. Erosion rate data from these experiments shows two things. First, the erosion rate from channel margin samples is greater than for thalweg samples, with the greatest difference observed for the rock surface that was exposed in the stream channel. Second, erosion rate decreases with depth beneath the original rock surface, by an order of magnitude in most cases. The erosion rate becomes steady at depths of 1–3 mm for channel margin samples and 0.1–0.4 mm for thalweg samples. Because only rock properties and microtopography vary throughout the sequence of mill experiments, these results suggest that Kr of the bedrock surface exposed in stream channels is higher at the margins than near the channel center and that Kr decreases over depths of ~1 mm. The simplest explanation for these patterns is that Kr is enhanced, at the bedrock surface and along the channel margins, due to the effects of weathering on rock strength and surface roughness. We hypothesize that a balance exists between weathering‐enhanced erodibility and episodic incision to allow channel margins to lower at rates similar to the thalweg.
The relative influence of land cover, hydrology, and in‐stream processing on the composition of dissolved organic matter in boreal streams
Authors: Kothawala Dolly N. , Ji Xing , Laudon Hjalmar , Ågren Anneli M. , Futter Martyn N. , Köhler Stephan J. , Tranvik Lars J.
Published: July 2015

Low‐order boreal streams are particularly sensitive interfaces where dissolved organic matter (DOM) is transported from soils to inland waters. Disentangling the relative influence of key environmental factors suspected to influence stream water DOM composition is highly relevant to predicting the reactivity and fate of terrestrial DOM entering inland waters. Here we examined changes to DOM composition using absorbance and fluorescence, from 17 boreal streams ranging from first to fourth orders, over 14 months, including the rarely studied winter season, and two snowmelt periods (n = 836). We also analyzed soil pore water samples from three forest soil lysimeters to a depth of 70 cm (n = 60). Of five identified fluorescing parallel factor analysis components, two (C4 and C5) expressed a clear mire wetland or forest signature, providing distinct molecular markers of dominant land cover. In fact, land cover alone explained 49% of the variability in DOM composition. In contrast, seasonal fluctuations in hydrology only contributed to minor shifts (8%) in the composition of stream water DOM, while in‐stream transformations to DOM composition were undetectable. These findings suggest that low‐order boreal streams act as a passive pipe, since in‐stream processing of DOM is restricted by short water residence times (6 h to 2 days). In addition, we demonstrated the sensitivity of optical approaches to distinguish between key terrestrial sources of DOM in the boreal landscape. By distinguishing the proportional leverage of key environmental controls on headwater stream DOM composition, we are better equipped to predict where and when key DOM transformations occur in the aquatic conduit.