bluuebunny/crossref_metadata_2025 huggingface dataset:
Ant Based Adaptive Directional Monitoring MAC Protocol Using Smart Antennas in MANET
Authors: Inamdar Sadanand , Babu B. Sathish , Yadahalli Ravi
Published: November 2017

In Mobile Ad Hoc Network (MAC), the existing MAC protocol based on the short busy advertisement is not an efficient method for data fragmentation. In addition, the data-fragment length adjustment according to the network environments is still an issue. In order to overcome this issue, in this article, the authors propose to design an Adaptive Directional Monitoring MAC (ADM-MAC) protocol for smart Antennas using Ant colony optimization (ACO) technique. In this technique, the network density and traffic intensity information is estimated using Ant Colony Optimization (ACO) technique and then passed on to the MAC protocol. Then data fragment transmission is performed by adaptively adjusting the directional monitoring period based on the packet size. By simulation results, the authors show that the proposed technique reduces the delay, packet drop due to collision and increases the throughput and packet delivery ratio.
Stakeholder Perceptions and Word-of-Mouth on CSR Dynamics
Authors: López-Fernández Andrée Marie , Silva Zamira Burgos
Published: November 2017

Corporate social responsibility is a strategy by which firms address social issues whilst tending to their profit enhancing objectives. However, is a socially responsible firm fulfilling its objectives if current and potential stakeholders perceive it to be unethical, engaging in poor and questionable practices? The article analyzes Big Data retrieved from Twitter related to five firms that have stated to be socially responsible but have yet to obtain stakeholders' legitimacy granted by the engagement in corporate social responsibility. The article contributes to the understanding and effects of firm dynamics in corporate social responsibility or lack thereof, on social networking sites by means of Big Data analysis.
Need of Algorithm Selection in Next Generation Optical Networks
Authors: Selvaraj P. , Nagarajan V.
Published: November 2017

The IP-based data networks and optical networks have been managed independently with layered protocol stack approach. Both of them were over-provisioned to manage any traffic anomalies and failures. The next generation optical network is expected to handle the needs of the emerging applications in a cost-effective way while satisfying the required QoT. In such scenario, the intents of the application layer must be accounted in the path computation. There is no single path computation algorithm exists which behave optimally under varying traffic conditions. Hence the need for the intent-driven automated algorithm selection was identified. The authors have phrased this intent specific lightpath provisioning problem as the path computation algorithm selection problem. An algorithm selection methodology was proposed with the study of the least congested path in ONOS based software defined controller environment. This approach is claimed as an amenable candidate for the next generation software-defined optical network.
Impact of density and sex-dependent larval competition on selected life history traits ofDrosophila melanogaster(Diptera: Drosophilidae)
Authors: Roy Sohini Singha , Aditya Gautam , Ghosh Sujay
Published: November 2017

An assessment of the effects of competitive behaviour and sex on seven selected life history traits ofDrosophila melanogasterMeigen (Diptera: Drosophilidae) was made under precisely regulated larval density. Contrary to the conditions of crowding, as considered in many previous studies, the low scale of density enabled assessment of the life history traits at the individual level with higher precision and low variations. The 0-day-old first instars were reared with the relative density of 1,2, 3, and 4 individuals with optimal food until the adults emerged. The life history traits like age at pupation, age at eclosion, adult body weight, adult body length, wing length, and adult survival were used as response variables. Both the density and sex of the competitors were considered as predictors of the life history traits and a stronger effect was evident in the female sex than in males, which is statistically significant. Result also revealed the effect of competitive behaviour was more intense in case of same sex competitors than of opposite sex. In all instances, the life history traits exhibited a trend of decreasing function with the increasing larval rearing density, in compliance with the norms of density-dependent effects on development ofDrosophilaFallén and similar insects.
Hijacking Subaltern’s history (broken bodies, broken voices): Decolonial critique of ‘Subaltern whiteness’ in South Africa
Authors: Kaunda Chammah J.
Published: November 2017

This article uses decolonial to critique the discourse of ‘subaltern whiteness’ by questioning some Afrikaner scholars’ morality of regarding ‘white Afrikaners as subaltern’. Subaltern designates submerged, subordinated, exploited or suppressed – those whose voices have been historically muted, their humanity stripped by those with sociopolitical and economic power. Within South Africa, this raises the question: to what extent can white Afrikaners be regarded as subaltern? The article proposes indivisibility of epistemic vulnerability and regenerative theological praxis both emerging within Afrikaner theological discussion as viable response to broken bodies of those who still bear the marks or scars of apartheid and rather not to seek to hijack their voice.
Twee bekroonde dramas deur Wessel Pretorius
Authors: Keuris Marisa
Published: November 2017

No abstract available.
Experiences of community service environmental health practitioners
Authors: Karamchand Anusha , Kistnasamy Emilie J.
Published: November 2017

Orientation: The community service initiative, a 1-year placement of health graduates, significantly improved human resource availability in the South African public health sector, even though the process was fraught with challenges. Although experiences in the curative health sector were assessed, the experiences of environmental health practitioners were yet to be studied.Research purpose: This study assessed the experiences of environmental health practitioners during their community service year.Motivation for the study: Anecdotal evidence suggested problems with the process. This study endeavoured to identify the challenges whilst taking cognisance of its effectiveness.Method: A total of n = 40 environmental health graduates from the Durban University of Technology who had concluded community service completed questionnaires in this crosssectional quantitative study. Descriptive statistics, means and standard deviations were used to analyse the data.Main findings: The timing of community service placements was critical as 58% of respondents had to repay study loans. The placement of married respondents (10%) outside KwaZuluNatal, however, could have had impacts on family structures. Only 68% felt stimulated by their job functions, and there arose challenges with accommodation and overtime duties. Respondents felt that their tertiary education did equip them and that engagement with senior personnel helped in their professional development. Even though most of the review of the community service year appeared to be positive, a majority of respondents did not intend to continue working or recommending their workplaces. Future career pathing showed that 79% would prefer to be employed outside the public sector.Practical and managerial implications: The process needs to be reviewed to strengthen human resource management and enhance retention in the often overloaded and under-resourced South African public health sector.Contribution: Relevant stakeholders can better plan, communicate and support affected parties through empowering management structures and providing logistical aid.
Mano y cerebro en el dibujo de arquitectura de Luis Moya (1904-1990)
Authors: Mosteiro Javier
Published: November 2017

La figura de Luis Moya Blanco (1904- 1990) constituye un caso singular –pero, a la vez, representativo– de lo que la práctica del dibujo puede llegar a ser en la conformación del pensamiento arquitectónico.

Esa singularidad de Moya reside en tres fundamentales aspectos: su intensa y muy particular correspondencia entre dibujar e idear arquitectura (con particular atención a la razón constructiva y geométrica); su ampliar exhaustivamente esa práctica a muy disímiles usos del dibujo de arquitectura, más allá de los estrictamente profesionales (paralelos y análisis gráficos, restituciones hipotéticas, fantasías, vistas…); y su profunda reflexión teórica sobre el papel del dibujo en relación al proceso de creación arquitectónica y a la formación de arquitectos.

Todo ello, mostrando la acción gráfica como lenguaje integrador de ideas en arquitectura, hace del caso de Moya uno de los capítulos más destacables de la historia del dibujo de arquitectura en la España del siglo xx.
Efectividad de un manual de autocuidado para el manejo de síntomas en personas colombianas que viven con VIH
Authors: Canaval-Erazo Gladys Eugenia , Valencia-Molina Claudia Patricia , Burgos-Dávila Delia Concepción , Cossio Alexandra
Published: November 2017

Estudio con resultados del nodo Cali, en colaboración con la Red Internacional de Enfermeras Investigadoras en VIH-Sida. Objetivo: medir la efectividad de un manual de autocuidado para el manejo de síntomas por VIH-Sida, comparando frecuencia de síntomas, calidad de vida, adherencia y utilidad del manual en personas con el virus del Sida que usaron el de autocuidado y las que usaron un manual de nutrición. Materiales y métodos: estudio cuasiexperimental con grupo experimental (manual de autocuidado para el manejo de síntomas) y control (manual de nutrición) con 51 personas; mediciones al inicio y a los dos meses. Resultados: los síntomas al inicio fueron 16, igual para los dos grupos. A los dos meses disminuyeron, la diferencia no fue significativa para la comparación entre grupos; se encontró aumento en el puntaje global de calidad de vida de 51 a 54 en el grupo experimental, y de 54 a 56 en el grupo control; la mayor utilidad fue para el manual de autocuidado con 88%, comparado con el de nutrición, 75%. Se reconoce la importancia de diseñar materiales educativos para responder a las necesidades de las personas que viven con el virus del Sida. Conclusión: el manual de autocuidado fue considerado útil por la mayoría de los participantes del grupo experimental.
UTILIZAÇÃO DOS DIFERENTES VERMICOMPOSTOS DE RESÍDUOS DA ETE COMO SUBSTRATO PARA PRODUÇÃO DE MUDAS DE ALFACE
Authors: Morales Deisy Arruda , Santana Natielo Almeida , Antoniolli Zaida Inês , Jacques Rodrigo Josemar , Kirst Gerusa Pauli , Steffen Ricardo Bemfica
Published: November 2017

The substrate used in the production of seedlings has a key role in early development of the plant. The objective of this study was to assess the potential of vermicompost as substrates for the production and development of seedlings of lettuce (L. sativa L.). The test was conducted in the greenhouse of the Department of Soils, Universidade Federal de Santa Maria, divided into 10 treatments and seven of ten repetitions. The treatments: T1-Red Residue (RVM), T2-Green Residue (RVD), T3-Residue Red: rice Husk “in nature” – 1: 1 (RVM: CAN 1: 1), T4-Residue Green: Rice husk “in nature” – 1: 1 (RVD: CAN 1: 1), T5-Residue Red: rice Husk Carbonized – 1: 1 (RVM: CAC 1: 1), T6 Residue Green: Rice husk Carbonized – 1: 1 (RVD: CAC 1: 1), T7-Residue Red: Residue green line – 1: 1 (RVM: RVD 1: 1), T8-Residue Green: Rice husk “in nature” – 3: 1 (RVD: CAN 3: 1), T9-Residue Red: rice Husk Carbonized – 3: 1 (RVM: CAC 3: 1) and T10 Fertile Turf (EB). Treatments that had better conditions on the number of leaves, height, fresh and dry biomass production of seedlings was treated with 50% residual red: 50% green waste - RVM: RVD. For the production of lettuce showed that the treatment is effective for plant height was RVM: RVD. For the other treatment variables RVM: CAC had better conditions when we compared the treatment that the CAC was in smaller proportions. It can be inferred that the RVM RVD and mixed with rice hulls and rice husk “fresh” can be used for the production of lettuce seedlings.
A PERCEPÇÃO E COGNIÇÃO CLIMÁTICA DOS AGRICULTORES E PESQUISADORES COMO SUBSÍDIO AO CULTIVO DE ROSEIRAS NO RIO GRANDE DO SUL
Authors: Wollmann Cássio Arthur , Galvani Emerson
Published: November 2017

The State of Rio Grande do Sul stands out, for decades, the national agricultural scenario, and even internationally for its high capacity anddiversity of agricultural production, among them, could not fail to highlight the flowers, the rose being the main flower grown and marketedin the state and national scenarios. In this sense, the climate being one of the main constraints to its cultivation, this study concerns to investigatethe perception of climate farmer roses, analyzing if the climatic conditions of Rio Grande do Sul have been favorable or unfavorableto the cultivation of roses. Were also interviewed technical people, whose purpose of crossing with the empirical scientific data collectedfrom the farmers. Were carried out fieldwork with questionnaires, and demonstrated the great knowledge by both technicians and farmers.What is striking is that both groups were asked the same questions of respondents, but in a different way, respecting your vocabulary, gettingin the end, similar responses, both in relation to the analysis of the plant and on the climate of Rio Grande do Sul. Overall, according tothe empirical view of farmers, the climate of Rio Grande do Sul, as well as its region of production, can be framed from regular to goodconditions for the cultivation of roses.
Proposition d’un modèle de maturité pour la gestion des risques : application au secteur industriel au Maroc
Authors: Nissoul Hakim , Riane Fouad , Mousrij Ahmed
Published: November 2017

Les statistiques sur les accidents liés aux risques industriels sont alarmantes. Les conséquences de ces accidents peuvent être très néfastes pour l’entreprise, ses biens, ses salariés, sa notoriété, son environnement et pour les populations avoisinantes. Pour réduire ces risques, l’entreprise doit avoir une politique de gestion des risques pertinente, clairement définie, correctement mise en oeuvre et inscrite dans une démarche globale d’amélioration continue. Dans cette perspective, nous proposons dans le présent papier un modèle de maturité en matière de gestion des risques pour les entreprises industrielles avec une approche de mesure et validation par l’étude de cas, appliquée à une quinzaine d’entreprises de droit marocain. Cet outil permettrait aux managers d’évaluer leur niveau de maîtrise des risques industriels, d’identifier les points faibles, et de prendre les décisions adéquates leur permettant de transformer leurs organisations en des organisations fiables.
Regulatory coiled-coil domains promote head-to-head assemblies of AAA+ chaperones essential for tunable activity control
Authors: Carroni Marta , Franke Kamila B , Maurer Michael , Jäger Jasmin , Hantke Ingo , Gloge Felix , Linder Daniela , Gremer Sebastian , Turgay Kürşad , Bukau Bernd , Mogk Axel
Published: November 2017

Ring-forming AAA+ chaperones exert ATP-fueled substrate unfolding by threading through a central pore. This activity is potentially harmful requiring mechanisms for tight repression and substrate-specific activation. The AAA+ chaperone ClpC with the peptidase ClpP forms a bacterial protease essential to virulence and stress resistance. The adaptor MecA activates ClpC by targeting substrates and stimulating ClpC ATPase activity. We show how ClpC is repressed in its ground state by determining ClpC cryo-EM structures with and without MecA. ClpC forms large two-helical assemblies that associate via head-to-head contacts between coiled-coil middle domains (MDs). MecA converts this resting state to an active planar ring structure by binding to MD interaction sites. Loss of ClpC repression in MD mutants causes constitutive activation and severe cellular toxicity. These findings unravel an unexpected regulatory concept executed by coiled-coil MDs to tightly control AAA+ chaperone activity.
Aalto open access fund pilot
Authors: Tiitinen Kalle
Published: November 2017

At the start of 2017, an Open Access Fund Pilot was launched to support Aalto University’s researchers with the OA article payments (APC-charges). The Open Access Fund Pilot is the first and one of a kind in Finland. This poster discusses current results and best practices learned from managing an Open Access fund in Finland’s context. The poster also presents the fund’s workflows including, e.g., departments’ personnel, publishers’ APC discount programs and the Learning Centre (previously the Library).Aalto University has reserved 120 000 euros for the pilot. Every department has its own quota for OA article payments. The quota depends on the publishing activity of the department during the past few years. The head of department makes final decisions for the use of the department quota. In order to get the funding, publications must meet certain criteria. The pilot funds only the open access publishing of journal and conference articles. Both Gold and Hybrid OA journals’ APC costs are accepted. Furthermore, Publication Forum, a classification of publication channels created by the Finnish scientific community, is used as a part of funding criteria. The Publication Forum’s levels are 1 = basic, 2 = leading, and 3 = top, and fully OA journals must be rated 1, 2 or 3 and Hybrid-model journals 2 or 3 in order to get the funding.The Learning Centre verifies that the publication meets the requirements of the OAF-pilot and checks if there are any discounts on APC-charges. If the publication meets all the requirements of the OAF-pilot, Learning Centre guides the researcher to apply for funding for APC-charges. The Learning Centre is also responsible for communications and informing of the OAF-pilot and for monitoring departments’ quotas. Currently, we have 34 applications from which most have met the requirements of AOF-pilot. So far, the total amount of funding granted is 29 796 €.
Oral 5-Hydroxytryptophan (5-HTP) Does not Affect Grooved Pegboard Test Performance
Authors: Gendle Mathew H. , Dowell Stanley W. , Paxton Rachel E. , O'Krent Rebecca H.
Published: November 2017

There is limited knowledge of the neurocognitive effects of the serotonin precursor 5-hydroxytryptophan (5-HTP), which is sold over-the-counter as a nutritional supplement. Animal studies have demonstrated that exogenous 5-HTP promotes the production of ectopic serotonin in dopaminergic neurons—an effect that may reduce dopamine output in these cells. Behavioral studies in humans have demonstrated specific 5-HTP induced cognitive deficits on the Iowa Gambling Task and the Tower of London task that are likely the result of reduced forebrain dopamine. However, it remains unclear if 5-HTP induced performance decrements observed on the Tower of London task were the result of a motor or cognitive impairment. The objective of this double-blind, placebo-controlled study was to clarify this point by determining if oral administration of 150 mg of 5-HTP disrupts fine motor control, as measured by the Grooved Pegboard Test. Seventy five university undergraduates received either a placebo or 5-HTP and completed the Grooved Pegboard Test. The groups did not differ in the amount of time needed to complete the place (p = 0.67) and remove (p = 0.48) components of the Grooved Pegboard Test. Therefore, 5-HTP induced reductions in performance on the Tower of London task appear to be cognitive in nature, and are unlikely to be the result of fine motor impairment (as measured by the Grooved Pegboard Test). These results also provide important safety information for 5-HTP by demonstrating that a 150 mg oral dose does not generally alter fine motor function.
The ability of laying pullets to negotiate two ramp designs as measured by bird preference and behaviour
Authors: Pettersson Isabelle C. , Weeks Claire A. , Norman Kate I. , Nicol Christine J.
Published: November 2017

Background

Laying hens are often kept in barn or free-range systems where they must negotiate level changes in the house to access resources. However, collisions and resultant keel fractures are commonplace. Producers sometimes add ramps to make raised areas more accessible but designs vary and very little research has investigated bird preference or behaviour when using different ramp designs, or the effect of ramp design on falls and collisions.

Methods

Two ramp designs were studied in an experimental setting—a ramp made of plastic poultry slats (grid ramp, GR) and a ramp made of wooden rungs (ladder ramp, LR). Sixty-four young female hens were trained to move to a food reward and this was used to test their behavioural responses when first negotiating the two different ramps during individual tests. Both upward and downward transitions were studied. Ramp preference was also tested using a room that replicated a commercial single-tier system with both types of ramp available. Birds were placed in this room in groups of 16 for three days and their use of the ramps studied.

Results

A greater percentage of birds successfully completed (reached the reward bowl) on the GR than the LR during both upward (58% vs 37%) and downward (83% vs 73%) transitions, and a smaller percentage of birds made zero attempts to use the GR than the LR (upwards: 13% vs 56%, downwards: 8% vs 26%). When making a downward transition, more hesitation behaviours were seen (head orientations, stepping on the spot, moving away) for the LR. However, more head orientations were seen for the GR during the upward transition. Birds were more likely to abort attempts (an attempt began when a bird placed both feet on the ramp) to move up the GR than the LR. Birds took longer to negotiate the LR than the GR in both directions, and more pauses were seen during a successful upward transition on the LR. Birds were more likely to move down the GR by walking/running whereas birds tended to jump over the entire LR. More collisions with the food reward bowl were seen for the LR. In the group tests, birds preferred to use the GR, with more transitions seen at all timepoints. However, in these tests, birds preferred to rest on the LR with greater numbers of birds counted on this type of ramp during scan sampling at all timepoints.

Discussion

Behavioural results suggest that the GR was easier for the birds to use than the LR, particularly on the downward transition. The GR was also less likely to result in collisions. However, the upward transition may be more difficult on the GR for some birds, potentially because of the inability to pause on a level surface during the transition. The results suggest that the GR was preferred by pullets for moving between a raised area and the ground but the LR was preferred for resting.
O caso do Brasil: valores, códigos deontológicos y nuevas reglas para el periodismo en las redes sociales
Authors:   Universidade Federal de Santa Catarina (Brasil), CHRISTOFOLETTI ROGÉRIO
Published: November 2017

El potencial de los nuevos medios, la explosión de información en las redes y el surgimiento de un consumidor de información que no se contenta con absorber pasivamente contenidos, ha propiciado cambios en el periodismo, incluso agilizando un escenario crítico para su supervivencia. Estos impactos no ocurren solo en el aspecto técnico de la profesión. También es necesario evaluar cómo está cambiando la ética periodística. Para ello, evaluamos cuatro documentos deontológicos brasileños, con el objetivo de extraer sus valores básicos. En la secuencia, observamos tres ejemplos nacionales de cómo los medios han estado buscando nuevas reglas para la conducta periodística en los nuevos medios y redes sociales. Los resultados permiten identificar vectores para el reajuste del periodismo a los desafíos éticos contemporáneos
Estructura del discurso televisivo: hacia una teoría de los géneros
Authors:   Universidad Autónoma de Barcelona (España), MAS MANCHÓN LLUÍS
Published: November 2017

En la actualidad, la televisión produce programas híbridos que combinan el discurso informativo, persuasivo y de entretenimiento. El peso específico de cada discurso varía en los tres niveles estructurales del mensaje de masas: nivel intencional (objetivos), estructural (contenido) y super-estructural (expresivo). Esto es fruto del proceso experimentado por la televisión a raíz de la revolución tecnológica y los cambios sociales. En este artículo se plantean los principios comunicativos por los que se organiza la información en los tres niveles estructurales de los programas para integrar los tres tipos discursivos. A diferencia de propuestas descriptivas y/o críticas, se apunta a una línea de investigación de los géneros televisivos desde el funcionalismo sistémico y el análisis textual. A través de ejemplos extremos de dominancia de diferentes discursos en los niveles estructurales, el modelo consigue explicar los procesos de hibridación, formula las preguntas de investigación adecuadas, y señala los principios estructurales para futuras variables de estudio.
Rol de los medios en la Convivencia social
Authors:   Pontificia Universidad Católica de Chile, DELPIANO MÁRIA OLGA
Published: November 2017

Cómo los medios –tanto los convencionales como los nuevos-contribuyen o no al encuentro y a la convivencia en estasociedad globalizada, flexible, multicultural es un tema que cruza esta número de Cuadernos de Información .
Nop5 interacts with the archaeal RNA exosome
Authors: Gauernack A. Susann , Lassek Christian , Hou Linlin , Dzieciolowski Julia , Evguenieva‐Hackenberg Elena , Klug Gabriele
Published: November 2017

The archaeal exosome, a protein complex responsible for phosphorolytic degradation and tailing of RNA, has an RNA‐binding platform containing Rrp4, Csl4, and DnaG. Aiming to detect novel interaction partners of the exosome, we copurified Nop5, which is a part of an rRNA methylating ribonucleoprotein complex, with the exosome of Sulfolobus solfataricus grown to a late stationary phase. We demonstrated the capability of Nop5 to bind to the exosome with a homotrimeric Rrp4‐cap and to increase the proportion of polyadenylated RNAin vitro, suggesting that Nop5 is a dual‐function protein. Since tailing of RNA probably serves to enhance RNA degradation, association of Nop5 with the archaeal exosome in the stationary phase may enhance tailing and degradation of RNA as survival strategy.
Enhanced Chlorophyll Concentrations Induced by Kuroshio Intrusion Fronts in the Northern South China Sea
Authors: Guo Lin , Xiu Peng , Chai Fei , Xue Huijie , Wang Dongxiao , Sun Jun
Published: November 2017

New evidences were provided that Kuroshio intrusion in winter is able to increase phytoplankton growth in the open ocean of the northern South China Sea (SCS) based on multiple data sources. Strong fronts due to Kuroshio intrusion and interactions with the SCS water are associated with intense upwelling, supplying high nutrients from the subsurface SCS water and increasing phytoplankton productivity in the frontal region. High chlorophyll is more dynamically related to these fronts than to the alongshore wind, wind stress curl, and eddy kinetic energy on interannual time scale. Further examinations suggest that fronts associated with Kuroshio intrusion into the SCS are linked with large‐scale climate variability. During El Niño years, stronger Kuroshio intrusion results in stronger fronts that generate intensified local upwelling and enhanced Luzon winter blooms.
Using Multitemporal and Multispectral Airborne Lidar to Assess Depth of Peat Loss and Correspondence With a New Active Normalized Burn Ratio for Wildfires
Authors: Chasmer L. E. , Hopkinson C. D. , Petrone R. M. , Sitar M.
Published: November 2017

Accuracy of depth of burn (an indicator of consumption) in peatland soils using prefire and postfire airborne light detection and ranging (lidar) data is determined within a wetland‐upland forest environment near Fort McMurray, Alberta, Canada. The relationship between peat soil burn depth and an “active” normalized burn ratio (ANBR) is also examined beneath partially and fully burned forest and understory canopies using state‐of‐the‐art active reflectance from a multispectral lidar compared with normalized burn ratio (NBR) derived from Landsat 7 ETM+. We find significant correspondence between depth of burn, lidar‐derived ANBR, and difference NBR (dNBR) from Landsat. However, low‐resolution optical imagery excludes peatland burn losses in transition zones, which are highly sensitive to peat loss via combustion. The findings presented here illustrate the utility of this new remote sensing technology for expanding an area of research where it has previously been challenging to spatially detect and quantify such wildfire burn losses.
Inflation Leading to a Slow Slip Event and Volcanic Unrest at Mount Etna in 2016: Insights From CGPS Data
Authors: Bruno V. , Mattia M. , Montgomery‐Brown E. , Rossi M. , Scandura D.
Published: November 2017

Global Positioning System (CGPS) data from Mount Etna between May 2015 and September 2016 show intense inflation and a concurrent Slow Slip Event (SSE) from 11 December 2015 to 17 May 2016. In May 2016, an eruptive phase started from the summit craters, temporarily stopping the ongoing inflation. The CGPS data presented here give us the opportunity to determine (1) the source of the inflating body, (2) the strain rate parameters highlighting shear strain rate accumulating along NE Rift and S Rift, (3) the magnitude of the SSE, and (4) possible interaction between modeled sources and other flank structures through stress calculations. By analytical inversion, we find an inflating source 5.5 km under the summit (4.4 km below sea level) and flank slip in a fragmented shallow structure accommodating displacements equivalent to a magnitude Mw6.1 earthquake. These large displacements reflect a complex mechanism of rotations indicated by the inversion of CGPS data for strain rate parameters. At the scale of the volcano, these processes can be considered precursors of seismic activity in the eastern flank of the volcano but concentrated mainly on the northern boundary of the mobile eastern flank along the Pernicana Fault and in the area of the Timpe Fault System.
Diverse Soil Carbon Dynamics Expressed at the Molecular Level
Authors: van der Voort T. S. , Zell C. I. , Hagedorn F. , Feng X. , McIntyre C. P. , Haghipour N. , Graf Pannatier E. , Eglinton T. I.
Published: November 2017

The stability and potential vulnerability of soil organic matter (SOM) to global change remain incompletely understood due to the complex processes involved in its formation and turnover. Here we combine compound‐specific radiocarbon analysis with fraction‐specific and bulk‐level radiocarbon measurements in order to further elucidate controls on SOM dynamics in a temperate and subalpine forested ecosystem. Radiocarbon contents of individual organic compounds isolated from the same soil interval generally exhibit greater variation than those among corresponding operationally defined fractions. Notably, markedly older ages of long‐chain plant leaf wax lipids (n‐alkanoic acids) imply that they reflect a highly stable carbon pool. Furthermore, marked 14C variations among shorter‐ and longer‐chain n‐alkanoic acid homologues suggest that they track different SOM pools. Extremes in SOM dynamics thus manifest themselves within a single compound class. This exploratory study highlights the potential of compound‐specific radiocarbon analysis for understanding SOM dynamics in ecosystems potentially vulnerable to global change.
Influence of Auroral Streamers on Rapid Evolution of Ionospheric SAPS Flows
Authors: Gallardo‐Lacourt Bea , Nishimura Y. , Lyons L. R. , Mishin E. V. , Ruohoniemi J. M. , Donovan E. F. , Angelopoulos V. , Nishitani N.
Published: November 2017

Subauroral polarization streams (SAPS) often show large, rapid enhancements above their slowly varying component. We present simultaneous observations from ground‐based all‐sky imagers and flows from the Super Dual Auroral Radar Network radars to investigate the relationship between auroral phenomena and flow enhancement. We first identified auroral streamers approaching the equatorward boundary of the auroral oval to examine how often the subauroral flow increased. We also performed the reverse query starting with subauroral flow enhancements and then evaluated the auroral conditions. In the forward study, 98% of the streamers approaching the equatorward boundary were associated with SAPS flow enhancements reaching ~700 m/s and typically hundreds of m/s above background speeds. The reverse study reveals that flow enhancements associated with streamers (60%) and enhanced larger‐scale convection (37%) contribute to SAPS flow enhancements. The strong correlation of auroral streamers with rapid evolution (approximately minutes) of SAPS flows suggests that transient fast earthward plasma sheet flows can often lead to westward SAPS flow enhancements in the subauroral region and that such enhancements are far more common than only during substorms because of the much more frequent occurrences of streamers under various geomagnetic conditions. We also found a strong correlation between flow duration and streamer duration and a weak correlation between SAPS flow velocity and streamer intensity. This result suggests that intense flow bursts in the plasma sheet (which correlate with intense streamers) are associated with intense SAPS ionospheric flows perhaps by enhancing the ring current pressure and localized pressure gradients when they are able to penetrate close enough to Earth.
Elastic Dispersion and Attenuation in Fully Saturated Sandstones: Role of Mineral Content, Porosity, and Pressures
Authors: Pimienta Lucas , Borgomano Jan V. M. , Fortin Jérôme , Guéguen Yves
Published: November 2017

Because measuring the frequency dependence of elastic properties in the laboratory is a technical challenge, not enough experimental data exist to test the existing theories. We report measurements of three fluid‐saturated sandstones over a broad frequency band: Wilkenson, Berea, and Bentheim sandstones. Those sandstones samples, chosen for their variable porosities and mineral content, are saturated by fluids of varying viscosities. The samples elastic response (Young's modulus and Poisson's ratio) and hydraulic response (fluid flow out of the sample) are measured as a function of frequency. Large dispersion and attenuation phenomena are observed over the investigated frequency range. For all samples, the variation at lowest frequency relates to a large fluid flow directly measured out of the rock samples. These are the cause (i.e., fluid flow) and consequence (i.e., dispersion/attenuation) of the transition between drained and undrained regimes. Consistently, the characteristic frequency correlates with permeability for each sandstone. Beyond this frequency, a second variation is observed for all samples, but the rocks behave differently. For Berea sandstone, an onset of dispersion/attenuation is expected from both Young's modulus and Poisson's ratio at highest frequency. For Bentheim and Wilkenson sandstones, however, only Young's modulus shows dispersion/attenuation phenomena. For Wilkenson sandstone, the viscoelastic‐like dispersion/attenuation response is interpreted as squirt flow. For Bentheim sandstone, the second effect does not fully follow such response, which could be due to a lower accuracy in the measured attenuation or to the occurence of another physical effect in this rock sample.
Oxidative Alteration of Ferrous Smectites and Implications for the Redox Evolution of Early Mars
Authors: Chemtob Steven M. , Nickerson Ryan D. , Morris Richard V. , Agresti David G. , Catalano Jeffrey G.
Published: November 2017

Surface conditions on early Mars were likely anoxic, similar to early Earth, but the timing of the evolution to oxic conditions characteristic of contemporary Mars is unresolved. Ferrous trioctahedral smectites are the thermodynamically predicted products of anoxic basalt weathering, but orbital analyses of Noachian‐aged terrains find primarily Fe3+‐bearing clay minerals. Rover‐based detection of Fe2+‐bearing trioctahedral smectites at Gale Crater suggests that ferrous smectites are the unoxidized progenitors of orbitally detected ferric smectites. To assess this pathway, we conducted ambient‐temperature oxidative alteration experiments on four synthetic ferrous smectites having molar Fe/(Mg + Fe) from 1.00 to 0.33. Smectite suspension in air‐saturated solutions produced incomplete oxidation (24–38% Fe3+/ΣFe). Additional smectite oxidation occurred upon reexposure to air‐saturated solutions after anoxic hydrothermal recrystallization, which accelerated cation and charge redistribution in the octahedral sheet. Oxidation was accompanied by contraction of the octahedral sheet (d(060) decreased from 1.53–1.56 Å to 1.52 Å), consistent with a shift toward dioctahedral structure. Ferrous smectite oxidation by aqueous hydrogen peroxide solutions resulted in nearly complete Fe2+ oxidation but also led to partial Fe3+ ejection from the structure, producing nanoparticulate hematite. Reflectance spectra of oxidized smectites were characterized by (Fe3+,Mg)2‐OH bands at 2.28–2.30 μm, consistent with oxidative formation of dioctahedral nontronite. Accordingly, ferrous smectites are plausible precursors to observed ferric smectites on Mars, and their presence in late‐Noachian sedimentary units suggests that anoxic conditions may have persisted on Mars beyond the Noachian.
Electrical Investigation of Metal‐Olivine Systems and Application to the Deep Interior of Mercury
Authors: Zhang Zhou , Pommier Anne
Published: November 2017

We report electrical conductivity measurements on metal‐olivine systems at about 5 and 6 GPa and up to 1,675°C in order to investigate the electrical properties of core‐mantle boundary (CMB) systems. Electrical experiments were conducted in the multianvil apparatus using the impedance spectroscopy technique. The samples are composed of one metal layer (Fe, FeS, FeSi2, or Fe‐Ni‐S‐Si) and one polycrystalline olivine layer, with the metal:olivine ratio ranging from 1:0.7 to 1:9.2. For all samples, we observe that the bulk electrical conductivity increases with temperature from 10−2.5 to 101.8 S/m, which is higher than the conductivity of polycrystalline olivine but lower than the conductivity of the pure metal phase at similar conditions. In some experiments, a conductivity jump is observed at the temperature corresponding to the melting temperature of the metallic phase. Both the metal:olivine ratio and the metal phase geometry control the electrical conductivity of the two‐layer samples. By combining electrical results, textural analyses of the samples, and previous studies of the structure and composition of Mercury's interior, we propose an electrical profile of the deep interior of the planet that accounts for a layered CMB‐outer core structure. The electrical model agrees with existing conductivity estimates of Mercury's lower mantle and CMB using magnetic observations and thermodynamic calculations, and thus, supports the hypothesis of a layered CMB‐outermost core structure in the present‐day interior of Mercury. We propose that the layered CMB‐outer core structure is possibly electrically insulating, which may influence the planet's structure and cooling history.
The Role of Three‐Dimensional Boundary Stresses in Limiting the Occurrence and Size of Experimental Landslides
Authors: Prancevic Jeffrey P. , Lamb Michael P. , Palucis Marisa C. , Venditti Jeremy G.
Published: November 2017

The occurrence of seepage‐induced shallow landslides on hillslopes and steep channel beds is important for landscape evolution and natural hazards. Infinite‐slope stability models have been applied for seven decades, but sediment beds generally require higher water saturation levels than predicted for failure, and controlled experiments are needed to test models. We initiated 90 landslides in a 5 m long laboratory flume with a range in sediment sizes (D = 0.7, 2, 5, and 15 mm) and hillslope angles (θ = 20° to 43°), resulting in subsurface flow that spanned the Darcian and turbulent regimes, and failures that occurred with subsaturated and supersaturated sediment beds. Near complete saturation was required for failure in most experiments, with water levels far greater than predicted by infinite‐slope stability models. Although 3‐D force balance models predict that larger landslides are less stable, observed downslope landslide lengths were typically only several decimeters, not the entire flume length. Boundary stresses associated with short landslides can explain the increased water levels required for failure, and we suggest that short failures are tied to heterogeneities in granular properties. Boundary stresses also limited landslide thicknesses, and landslides progressively thinned on lower gradient hillslopes until they were one grain diameter thick, corresponding to a change from near‐saturated to supersaturated sediment beds. Thus, landslides are expected to be thick on steep hillslopes with large frictional stresses acting on the boundaries, whereas landslides should be thin on low‐gradient hillslopes or in channel beds with a critical saturation level that is determined by sediment size.
The Response of Equatorial Ionization Anomaly in 120°E to the Geomagnetic Storm of 18 August 2003 at Different Altitudes From Multiple Satellite Observations
Authors: Luo Weihua , Zhu Zhengping , Xiong Chao , Chang Shanshan
Published: November 2017

In this paper, the variations of equatorial ionization anomaly (EIA) in 120°E region during the 17–20 August 2003 storm are investigated from measurements of satellites at different altitudes from Challenging Minisatellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE), scientific satellite of the Republic of China (ROCSAT‐1), and Defense Meteorological Satellite Program missions. The results showed that (1) at CHAMP and GRACE altitudes, the EIA was inhibited before the storm sudden commencement (SSC) and also during the storm recovery phase, but it was enhanced significantly during the storm main phase of the storm. (2) The variations of EIA strength and interhemispheric density asymmetry of the two crests were similar at CHAMP and GRACE altitudes, while the location asymmetry of the two crests was different at CHAMP and GRACE altitudes. (3) The irregularities and long‐duration scintillation were recorded before the SSC of the storm, when the EIA was inhibited. The irregularities at different altitudes and short‐duration scintillation were observed during the main phase of the storm, when the EIA was enhanced significantly. (4) The EIA enhancement can be attributed to the enhanced electric field due to prompt penetration interplanetary electric fields and the storm time neutral wind, while the suppression of EIA on 17 August can be attributed to the absence of the equatorward neutral wind, which varied with the altitudes. The EIA inhibition during the recovery phase may be caused mainly by the neutral wind. Our results suggest that the neutral wind is the crucial factor causing the variations in EIA and the occurrence of scintillation.
Multinational Qualitative Research Study Exploring the Patient Experience of Raynaud's Phenomenon in Systemic Sclerosis
Authors: Pauling John D. , Domsic Robyn T. , Saketkoo Lesley A. , Almeida Celia , Withey Jane , Jay Hilary , Frech Tracy M. , Ingegnoli Francesca , Dures Emma , Robson Joanna , McHugh Neil J. , Herrick Ariane L. , Matucci‐Cerinic Marco , Khanna Dinesh , Hewlett Sarah
Published: November 2017

Objective

Raynaud's phenomenon (RP) is the most common manifestation of systemic sclerosis (SSc). RP is an episodic phenomenon, not easily assessed in the clinic, leading to reliance on self‐report. A thorough understanding of the patient experience of SSc‐RP is essential to ensuring that patient‐reported outcome (PRO) instruments capture domains important to the target patient population. We report the findings of an international qualitative research study investigating the patient experience of SSc‐RP.

Methods

Focus groups of SSc patients were conducted across 3 scleroderma centers in the US and UK, using a topic guide and a priori purposive sampling framework devised by qualitative researchers, SSc patients, and SSc experts. Focus groups were audio recorded, transcribed, anonymized, and analyzed using inductive thematic analysis. Focus groups were conducted until thematic saturation was achieved.

Results

Forty SSc patients participated in 6 focus groups conducted in Bath (UK), New Orleans (Louisiana), and Pittsburgh (Pennsylvania). Seven major themes were identified that encapsulate the patient experience of SSc‐RP: physical symptoms, emotional impact, triggers and exacerbating factors, constant vigilance and self‐management, impact on daily life, uncertainty, and adaptation. The interrelationship of the 7 constituent themes can be arranged within a conceptual map of SSc‐RP.

Conclusion

We have explored the patient experience of SSc‐RP in a diverse and representative SSc cohort and identified a complex interplay of experiences that result in significant impact. Work to develop a novel PRO instrument for assessing the severity and impact of SSc‐RP, comprising domains/items grounded in the patient experiences of SSc‐RP identified in this study, is underway.
Upregulation of epidermal gap junctional proteins in patients with venous disease
Authors: Kanapathy M , Simpson R , Madden L , Thrasivoulou C , Mosahebi A , Becker D L , Richards T
Published: November 2017

Background

Leg ulceration is a feared complication of venous insufficiency. It is not known whether varicose veins predispose skin to poor wound healing. The expression pattern of gap junctional protein connexin, a known marker of poor wound healing, was investigated across various stages of venous disease.

Methods

Patients undergoing intervention for varicose veins were assessed according to the Clinical Etiologic Anatomic Pathophysiologic (CEAP) classification of varicose veins. Paired 4-mm punch biopsies were taken from above the ankle (pathological) and above the knee (control). Tissues were stained with haematoxylin and eosin, and for connexin 43, connexin 30 and connexin 26.

Results

Forty-eight paired biopsies were taken (12 each for CEAP class C0, C2, C4 and C6). The pathological skin showed progressive epithelial hyperthickening, an increase in the number and depth of rete ridges, increased inflammation and loss of dermal architecture with disease progression from C4 onwards. The overall absolute connexin expression and mean connexin expression per cell in the pathological skin similarly increased across the CEAP classes from as early as C2. Increasing levels of connexin in control skin were also noted, indicating progression of the disease proximally. Connexin 43 expression showed the strongest positive correlation between pathological and control skin.

Conclusion

Connexins were overexpressed in patients with simple varicose veins, with a stepwise increased expression through venous eczema to ulceration. Connexin 43 is a potential biomarker for venous disease. This finding suggests that varicose veins predispose skin to poor wound healing. Surgical relevanceThe overexpression of connexins, a family of gap junctional proteins, is known to cause poor healing in venous leg ulceration. It is not known whether there is any association with superficial venous disease. Here, connexin proteins were overexpressed in patients with uncomplicated varicose veins, before histological skin changes. Connexin could be a biomarker of venous disease progression.