bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Expression Analysis for RNA-Seq: An Overview of Statistical Methods and Computational Software
Authors: Huang Huei-Chung , Niu Yi , Qin Li-Xuan
Published: December 2015

Deep sequencing has recently emerged as a powerful alternative to microarrays for the high-throughput profiling of gene expression. In order to account for the discrete nature of RNA sequencing data, new statistical methods and computational tools have been developed for the analysis of differential expression to identify genes that are relevant to a disease such as cancer. In this paper, it is thus timely to provide an overview of these analysis methods and tools. For readers with statistical background, we also review the parameter estimation algorithms and hypothesis testing strategies used in these methods.
Pursuing Excellence in Clinical Learning Environments
Authors: Wagner Robin , Weiss Kevin B. , Passiment Morgan L. , Nasca Thomas J.
Published: December 2015

The Accreditation Council for Graduate Medical Education (ACGME) has launched a new shared learning collaborative as part of its larger Clinical Learning Environment Review (CLER) initiative. The collaboration, called Pursuing Excellence in Clinical Learning Environments, aims to improve teaching practices and patient care in the hospitals, medical centers, and ambulatory care sites where residents and fellows pursue their formal clinical training in a specialty or subspecialty. The Pursuing Excellence Initiative (PEI) builds on the 2015 report of findings of the CLER program. These findings demonstrate variability across the nation's teaching hospitals in addressing 6 key focus areas.

PEI sets up a shared system of collaborative learning among participating sites of ACGME-accredited institutions, in which early participants share advances that will be disseminated through an expanding circle of other participants. The ACGME will award funding to encourage participation in the first major component of PEI. The goal is to stimulate high-leverage changes that will broadly improve patient care and clinical learning environments across the nation.
Soil moisture sensor calibration for organic soil surface layers
Authors: Bircher S. , Andreasen M. , Vuollet J. , Vehviläinen J. , Rautiainen K. , Jonard F. , Weihermüller L. , Zakharova E. , Wigneron J.-P. , Kerr Y. H.
Published: December 2015

Abstract. This paper's objective is to present generic calibration functions for organic surface layers derived for the soil moisture sensors Decagon ECH2O 5TE and Delta-T ThetaProbe ML2x, using material from northern regions, mainly from the Finish Meteorological Institute's Arctic Research Center in Sodankylä and the study area of the Danish Center for Hydrology HOBE. For the Decagon 5TE sensor such a function is currently not reported in literature. Data were compared with measurements from underlying mineral soils including laboratory and field measurements. Shrinkage and charring during drying were considered. For both sensors all field and lab data showed consistent trends. For mineral layers with low soil organic matter (SOM) content the validity of the manufacturer's calibrations was demonstrated. Deviating sensor outputs in organic and mineral horizons were identified: for the Decagon 5TE apparent relative permittivities at a given moisture content decreased for increased SOM content, which was attributed to an increase of bound water in organic materials with large surface areas compared to the studied mineral soils. ThetaProbe measurements from organic horizons showed stronger non-linearity in the sensor response and signal saturation in the high level data. The derived calibration fit functions between sensor response and volumetric water content hold for samples spanning a wide range of humus types with differing SOM characteristics. This strengthens confidence in their validity under various conditions, rendering them highly suitable for large-scale applications in remote sensing and land surface modeling studies. Agreement between independent Decagon 5TE and ThetaProbe time series from an organic surface layer at the Sodankylä site was significantly improved when the here proposed fit functions were used. Decagon 5TE data also well-reflected precipitation events. Thus, Decagon 5TE network data from organic surface layers at the Sodankylä and HOBE sites are based on the here proposed natural log fit. The newly derived ThetaProbe fit functions should be used for hand-held applications only, but in that case proof of value for the acquisition of instantaneous large-scale soil moisture estimates.
Habitat Suitability Analysis of Suaeda heteroptera in Wetlands of Laizhou West Bank Based on GIS
Authors: Shao Kai , Ji Jing , Zhou Bin
Published: December 2015

Along with the development of marine economy, west bank of Laizhou Bay, efficient and economical core area, suffered some degree of damage, and local habitats of Suaeda heteroptera were correspondingly affected. Using geographic information systerms (GIS) technology and HIS model, analysis on habitat suitability of S. heteroptera in tital wetlands of Lanzhou west bank. The results show that: Although high soil salinity in the study area, and serious petroleum and heavy metal pollution, the regional environmental conditions meet the basic survival and growth requirement of S. heteroptera, because its strong salt tolerance, as well as petroleum and heavy metal absorption and accumulation ability, consequently, S. heteroptera can be relatively normally grow in this habitat. Generally, Laizhou Bay is a highly or moderate suitable area for S. heteroptera growth.
Sources and Levels of Foreign Language Speaking Anxiety of English as a Foreign Language University Students with regard to Language Proficiency and Gender
Authors: Debreli Emre , Demirkan Seren
Published: December 2015

Although foreign language anxiety is a widely explored subject in the area of English as a Foreign Language (EFL), studies that focus on the speaking anxiety in EFL, as well as the gender and language proficiency level–anxiety relationship, are rare. The present study investigates the phenomenon in an EFL context and analyzes the levels of EFL students’ speaking anxiety and the sources that make them anxious. It also explores whether there is any relationship between anxiety and students’ language proficiency level and gender. Data were gathered from 196 Turkish and Turkish Cypriot students through questionnaires (Foreign Language Classroom Anxiety Scale), as well as through semi-structured interviews with 10 students who participated in the questionnaires. The findings indicated that the students generally had low level of speaking anxiety, although students with a higher level of language proficiency had a higher level of anxiety compared with that for students with a lower level of language proficiency. No statistically meaningful difference was observed with regard to students’ gender and anxiety levels. Factors that caused anxiety—such as difficulty in pronunciation, being asked immediate questions by the teacher, not understanding the question asked by the teacher—not found in the current literature also emerged from the present study. Implications for teacher education are also discussed.
A Generic Algorithm to Determine Maximum Bottleneck Node Weight-based Data Gathering Trees for Wireless Sensor Networks
Authors: Meghanathan Natarajan
Published: December 2015

We propose a generic algorithm to determine maximum bottleneck node weight-based data gathering (MaxBNW-DG) trees for wireless sensor networks (WSNs) and compare the performance of the MaxBNW-DG trees with those of maximum and minimum link weight-based data gathering trees (MaxLW-DG and MinLW-DG trees). Assuming each node in a WSN graph has a weight, the bottleneck weight for the path from a node u to the root node of the DG tree is the minimum of the node weights on the path (inclusive of the weights of the end nodes). The MaxBNW-DG tree algorithm determines a DG tree such that each node has a path of the largest bottleneck weight to the root node. We observe the MaxBNW-DG trees to incur lower height, larger percentage of nodes as leaf nodes and a larger weight per intermediate node compared to the leaf node; the tradeoff being a larger a network-wide data aggregation delay due to larger number of child nodes per intermediate node. The MaxBNW-DG algorithm could be used to determine DG trees with larger trust score, larger energy (and other such criterion for node weight) per intermediate node compared to the leaf node.
A Robust and Energy Efficient Cooperative Spectrum Sensing Scheme in Cognitive Wireless Sensor Networks
Authors: Men Shaoyang , Chargé Pascal , Pillement Sébastien
Published: December 2015

Cooperative spectrum sensing (CSS) is able to effectively solve the hidden terminal, depth attenuation, multipath shadows and other issues which are not addressed by the single-user sensing. Therefore, it has attracted a large amount of interest and several CSS algorithms have been proposed. However, they are not specifically tailored for cognitive wireless sensor networks (CWSNs) where transmission reliability, power management and interference avoidance are critical issues. In this paper, we propose a robust and energy efficient CSS scheme in CWSNs. Firstly, taking into account the limited energy of sensor node, especially the mobile node, we introduce the nodes of the network into multiple clusters for the CSS in order to save energy consumed in reporting results and exchanging information and extend the lifetime of the network. Secondly, we consider that some cognitive nodes may not work as expected. Hence, facing the problem of faulty nodes in clusters, we propose an evaluation method which considers simultaneously the node reliability and the mutually supportive degree among different nodes to support adapted decisions. Finally, after removing the node of low credibility, the energy efficiency and reliability of each cluster are improved significantly. Simulation results allow to validate that the proposed method outperforms the state of the art in energy efficiency and detection reliability, even in presence of faulty nodes.
Impact of Learning Algorithms on Random Neural Network based Optimization for LTE-UL Systems
Authors: Adeel Ahsan , Larijani Hadi , Javed Abbas , Ahmadinia Ali
Published: December 2015

This paper presents an application of context-aware decision making to the problem of radio resource management (RRM) and inter-cell interference coordination (ICIC) in long-term evolution-uplink (LTE-UL) system. The limitations of existing analytical, artificial intelligence (AI), and machine learning (ML) based approaches are highlighted and a novel integration of random neural network (RNN) based learning with genetic algorithm (GA) based reasoning is presented. In first part of the implementation, three learning algorithms (gradient descent (GD), adaptive inertia weight particle swarm optimization (AIWPSO), and differential evolution (DE)) are applied to RNN and two learning algorithms (GD and levenberg-marquardt (LM)) are applied to artificial neural network (ANN). In second part of the implementation, the GA based reasoning is applied to the trained ANN and RNN models for performance optimization. Finally, the ANN and RNN based optimization results are compared with the state-of-the-art fractional power control (FPC) schemes in terms of user throughput and power consumption. The simulation results have revealed that an RNN-DE (RNN trained with DE algorithm) based cognitive engine (CE) can provide up to 14% more cell capacity along with 6dBm and 9dBm less user power consumption as compared to RNN-GD (RNN trained with GD algorithm) and FPC methods respectively.
“Running with the Hounds”: The Nazi Pygmalion
Authors: Conolly-Smith Peter
Published: December 2015

The 1941 Berlin-based Prussian State Theater production of Bernard Shaw's Pygmalion sheds light on the popularity of Shaw in Third Reich Germany, the playwright's conflicted politics, and the complex and often-contradictory forces at work in National Socialist cultural policy. Providing background on Pygmalion's long-standing popularity among German audiences, this essay's analysis of the lavish 1941 production draws on contemporary press coverage as well as on the director's hand-annotated script in order to examine Shaw's complicated relationship with the Third Reich.
Bowing a Knee to GBS: Augustus John on T. E. Lawrence
Authors: Weintraub Stanley
Published: December 2015

It would appear that British artist Augustus John slyly included the face of GBS in his pen portrait of T. E. Lawrence.
Financial Fragility and Central Bank: Are Minsky's Crisis and Austrian Business Cycle are Complementary?
Authors: Facchini François
Published: December 2015

This article explains why Minsky's post-keynesian explanation tells only one side of the crisis' story. Indeed, the financial fragility of markets explains mainly the activity of Central bank i.e. the lender of last resort which increases the moral hazard phenomena and the socialization of risks. The regulated capitalism is, in this perspective, the cause of market instability and financial fragility. Indeed, moral hazard encourages commercial banks to take risks. In that respect, the economic policies implemented to manage the crisis of 2008 are inadequate.
Target Capital Structure Determinants and Speed of Adjustment Analysis to Address the Keynes-Hayek Debate
Authors: Getzmann André , Sebastian Lang Sebastian Lang , Klaus Spremann Klaus Spremann
Published: December 2015

According to F. A. Hayek, Keynes' General Theory neglects an analysis of the production structure. As a contribution to this research gap, we look at companies' decisions to finance investments and at their agility to adjust their capital structure. We thus study the relationship between capital structure to finance corporate production and shifts in aggregate demand. Target capital structure determinants and speeds of adjustment to these target capital structures will be analyzed for a geographically comprehensive sample of 2,706 companies listed in Asia, Europe and the U.S.A. in the period 1995 â€“ 2009. Aggregate demand turns out to be the coordinating force which determines managers' choices of target capital structures. The speed of adjustments towards target capital structures indicate that firms are agile in adapting to their targets. Our results provide evidence on Keynes' General Theory from a firm level perspective: Firms respond quickly to shifts in aggregate demand by adjusting capital and production structure correspondingly.
Homoclinic Bifurcation and Endogenous Cycles in the Dynamic IS-LM Model
Authors: Bella Giovanni
Published: December 2015

This paper contributes to the new keynesian literature by showing that stable endogenous cycles can emerge as equilibrium solutions of the traditional IS-LM model. The application of the original Bogdanov-Takens theorem allows us to determine the regions of the parametric space where the model exhibits a global indeterminate solution, and a low-growth trapping region, characterized by a continuum of equilibrium trajectories in the proximity of a homoclinic bifurcation.
Incidencia de la Formación del Profesorado en sus creencias sobre el valor de las TIC en la enseñanza de la Música
Authors: Colás-Bravo Pilar , Hernández Portero Guadalupe
Published: December 2015

El profesorado de Música de Educación Secundaria cuenta con diversas vías de acceso a la docencia, que derivan en la presencia en las aulas de profesores con distinta formación inicial y, como consecuencia, diferentes maneras de entender la Educación Musical.
La presencia cada vez más acuciante de las Tecnologías de la Información y la Comunicación (TIC) en la sociedad y en las aulas provoca la necesidad de que el profesorado tenga que responder a esta nueva situación educativa a través de una adecuada formación. Por ello a través de esta investigación tratamos de conocer cuál es
la formación en TIC del profesorado de Música y su influencia en los factores que inciden en el uso de estas tecnologías. Para ello nos hemos valido del análisis de un cuestionario respondido por 53 profesores de Música de Institutos de Educación Secundaria de Andalucía, de cuyos resultados se deriva que el nivel de formación del profesorado en TIC incide en la conformación de sus creencias, percepciones y reacciones emocionales ante el
uso de las TIC. Por tanto, resulta fundamental abordar,
mejorar y ampliar la formación del profesorado en este ámbito para permitirle acercarse a una realidad social de la que forma parte, especialmente en el caso del profesorado de Música, pues esta materia cuenta con unos recursos tecnológicos específicos con una clara aplicación didáctica que posibilitaría un acercamiento de
los alumnos a la Música de una forma más atractiva y motivadora.
Investigación-acción para conseguir grupos colaborativos eficaces
Authors: Labrador-Piquer María José , Andreu-Andrés María Ángeles
Published: December 2015

Tras un breve recorrido por los orígenes de la investigación-acción, en línea con la práctica reflexiva del profesor investigador, este estudio plantea las dificultades encontradas en dos grupos de estudiantes que presentan unos resultados ineficaces de trabajo grupal y describe la técnica colaborativa empleada en la experiencia para lograr unos resultados satisfactorios, el puzle de Aronson. Tras su implementación se recogen los resultados y conclusiones obtenidas a través de un análisis cualitativo (para estudiar la percepción del alumno) y uno cuantitativo (para analizar el número de miembros de los grupos de trabajo que desarrollan sus tareas adecuadamente). Estos resultados pueden ayudar a los docentes a reflexionar y realizar los cambios necesarios en estas y en otras situaciones educativas.
Competencias básicas: el caso de la comunicación lingüística en alumnos de 4º de Primaria de la provincia de León
Authors: Cantón Mayo Isabel , Prieto Carnicero Luis Ángel
Published: December 2015

En este artículo se analiza, por medio del estudio llevado a cabo entre el alumnado de 4º de Primaria de los centros escolares de la provincia de León, el nivel de competencia lingüística adquirido por estos alumnos en dicha provincia. La investigación se plantea a partir del cambio que la introducción de las competencias básicas han propiciado en los currículos escolares. Las categorías estudiadas son: influencia del profesor, gramática, hábito lector, diferencias por sexos, expresión oral, creatividad, influencia de las TIC, y tipo de centros. Los resultados son coincidentes con otras investigaciones en algunas categorías pero también hay discrepancias novedosas en otras.
El Aprendizaje Basado en la Resolución de Problemas y su efectividad en el Desarrollo de la Metacognición
Authors: Ley Fuentes Martha Georgina
Published: December 2015

Esta investigación tuvo como propósito determinar la efectividad del aprendizaje basado en la resolución de problemas, en el desarrollo de la metacognición de  estudiantes universitarios de una universidad virtual. Para determinar la efectividad de la estrategia de resolución de problemas en el desarrollo de la metacognición de los estudiantes, se implementó un diseño cuasi experimental, con pre y post test. En la investigación participaron 34 estudiantes, que recibieron un pretest para medir la metacognición y posteriormente fueron sometidos a un tratamiento instruccional. Después del tratamiento los participantes presentaron la postprueba metacognitiva, para determinar la efectividad del tratamiento en la metacognición. A partir del análisis de los resultados, se comprobó que los niveles de metacognición aumentaron después del tratamiento. De esta manera se comprobó la efectividad del aprendizaje basado en la resolución de problemas en el desarrollo de la metacognición de estudiantes universitarios de una universidad virtual mexicana.
Many-to-One Boundary Labeling
with Backbones
Authors: Bekos Michael , Cornelsen Sabine , Fink Martin , Hong Seok-Hee , Kaufmann Michael , Nöllenburg Martin , Rutter Ignaz , Symvonis Antonios
Published: December 2015

We study a boundary labeling problem, where multiple points may connect to the same label. In this new many-to-one model, a horizontal backbone reaches out of each label into the feature-enclosing rectangle. Feature points that need to be connected to this label are linked via vertical line segments to the backbone. We present dynamic programming algorithms for minimizing the total number of label occurrences and for minimizing the total leader length of crossing-free backbone labelings. When crossings are allowed, we aim at obtaining solutions with the minimum number of crossings. This can be achieved efficiently in the case of fixed label order; however, in the case of flexible label order we show that minimizing the number of leader crossings is NP-hard.
Frequency-selective control of cortical and subcortical networks by central thalamus
Authors: Liu Jia , Lee Hyun Joo , Weitz Andrew J , Fang Zhongnan , Lin Peter , Choy ManKin , Fisher Robert , Pinskiy Vadim , Tolpygo Alexander , Mitra Partha , Schiff Nicholas , Lee Jin Hyung
Published: December 2015

Central thalamus plays a critical role in forebrain arousal and organized behavior. However, network-level mechanisms that link its activity to brain state remain enigmatic. Here, we combined optogenetics, fMRI, electrophysiology, and video-EEG monitoring to characterize the central thalamus-driven global brain networks responsible for switching brain state. 40 and 100 Hz stimulations of central thalamus caused widespread activation of forebrain, including frontal cortex, sensorimotor cortex, and striatum, and transitioned the brain to a state of arousal in asleep rats. In contrast, 10 Hz stimulation evoked significantly less activation of forebrain, inhibition of sensory cortex, and behavioral arrest. To investigate possible mechanisms underlying the frequency-dependent cortical inhibition, we performed recordings in zona incerta, where 10, but not 40, Hz stimulation evoked spindle-like oscillations. Importantly, suppressing incertal activity during 10 Hz central thalamus stimulation reduced the evoked cortical inhibition. These findings identify key brain-wide dynamics underlying central thalamus arousal regulation.
How to Make Finance Scholarship More Creative and Equitable: An Author’s Suggestions to Editors and Referees *
Authors: Subrahmanyam Avanidhar
Published: December 2015

Editing high-quality finance journals is challenging, and it also requires careful thought on the optimal governance processes required to ensure equity, particularly given the large number of submissions to these journals. Enhancing and maintaining incentives for authors to be creative is also important. In this paper, I discuss issues arising from subjectivity in referees’ reports in finance journals and present a list of editorial suggestions that might improve authors’ experiences and enhance the quality of submissions to these journals.
Semantic UI: Automated Creation of Semantically Personalized User Interface
Authors: Khriyenko O.
Published: December 2015

Information representation plays very important role for services and applications to be more attractive for end user. One design cannot fit varied preferences and be suitable for all users. User driven customization of user interface applied for particular application or service do not influence at overall satisfaction of a user and usability of other applications and services. Therefore, in the paper authors tackle challenges of UI personalization on semantic level; and present a framework for adaptive UI development, driven by personal semantic user profile and mashup of reusable adaptive visualization modules. Considering human as a powerful integrated part of IoT environment, UI adaptation and personalization framework has been extended with automated ontology-based UI creation (Semantic Scanner concept). Presented approach of on-the-fly semantically-driven adaptive UI creation facilitates a process of human integration into machine-oriented infrastructure.
Security Awarness Program for Customers Using Online Banking
Authors: Zaabi Khulood Al , Tubaishat Abdallah
Published: December 2015

Due to the increasing demand on electronic payments, fraud methods are also increasing which has resulted in the loss of millions of dollars worldwide each year in the banking sector. Several studies have been conducted to counter against fraud in the banking domain and to come up with ways to secure online payments. None of these studies, however, have resulted in a comprehensive awareness program which targets customer banking. The purpose of this research is to propose an awareness program, Information Security Awareness Program, dubbed ISAP. We believe that such a program is needed for the following reasons: a) in order to enhance the level of trust in online banking, b) to protect each customer’s personal information and c) to comply with the online bank requirements. We have identified several online frauds, and then we recommended some best practices for online protection in the following areas: online shopping, online protection, password protection, operating system protection, identity theft protection, and debit/credit card protection.
Drug delivery systems for ovarian cancer treatment: a systematic review and meta-analysis of animal studies
Authors: Raavé René , de Vries Rob B.M. , Massuger Leon F. , van Kuppevelt Toin H. , Daamen Willeke F.
Published: December 2015

Current ovarian cancer treatment involves chemotherapy that has serious limitations, such as rapid clearance, unfavorable biodistribution and severe side effects. To overcome these limitations, drug delivery systems (DDS) have been developed to encapsulate chemotherapeutics for delivery to tumor cells. However, no systematic assessment of the efficacy of chemotherapy by DDS compared to free chemotherapy (not in a DDS) has been performed for animal studies. Here, we assess the efficacy of chemotherapy in DDS on survival and tumor growth inhibition in animal studies. We searched PubMed and EMBASE (via OvidSP) to systematically identify studies evaluating chemotherapeutics encapsulated in DDS for ovarian cancer treatment in animal studies. Studies were assessed for quality and risk of bias. Study characteristics were collected and outcome data (survival/hazard ratio or tumor growth inhibition) were extracted and used for meta-analyses. Meta-analysis was performed to identify and explore which characteristics of DDS influenced treatment efficacy. A total of 44 studies were included after thorough literature screening (2,735 studies found after initial search). The risk of bias was difficult to assess, mainly because of incomplete reporting. A total of 17 studies (377 animals) and 16 studies (259 animals) could be included in the meta-analysis for survival and tumor growth inhibition, respectively. In the majority of the included studies chemotherapeutics entrapped in a DDS significantly improved efficacy over free chemotherapeutics regarding both survival and tumor growth inhibition. Subgroup analyses, however, revealed that cisplatin entrapped in a DDS did not result in additional tumor growth inhibition compared to free cisplatin, although it did result in improved survival. Micelles did not show a significant tumor growth inhibition compared to free chemotherapeutics, which indicates that micelles may not be a suitable DDS for ovarian cancer treatment. Other subgroup analyses, such as targeted versus non-targeted DDS or IV versus IP administration route, did not identify specific characteristics of DDS that affected treatment efficacy. This systematic review shows the potential, but also the limitations of chemotherapy by drug delivery systems for ovarian cancer treatment. For future animal research, we emphasize that data need to be reported with ample attention to detailed reporting.
Metagenomic and satellite analyses of red snow in the Russian Arctic
Authors: Hisakawa Nao , Quistad Steven D. , Hester Eric R. , Martynova Daria , Maughan Heather , Sala Enric , Gavrilo Maria V. , Rohwer Forest
Published: December 2015

Cryophilic algae thrive in liquid water within snow and ice in alpine and polar regions worldwide. Blooms of these algae lower albedo (reflection of sunlight), thereby altering melting patterns (Kohshima, Seko & Yoshimura, 1993; Lutz et al., 2014; Thomas & Duval, 1995). Here metagenomic DNA analysis and satellite imaging were used to investigate red snow in Franz Josef Land in the Russian Arctic. Franz Josef Land red snow metagenomes confirmed that the communities are composed of the autotrophChlamydomonas nivalisthat is supporting a complex viral and heterotrophic bacterial community. Comparisons with white snow communities from other sites suggest that white snow and ice are initially colonized by fungal-dominated communities and then succeeded by the more complexC. nivalis-heterotroph red snow. Satellite image analysis showed that red snow covers up to 80% of the surface of snow and ice fields in Franz Josef Land and globally. Together these results show thatC. nivalissupports a local food web that is on the rise as temperatures warm, with potential widespread impacts on alpine and polar environments worldwide.
Watch your language: Power words at the human–nature interface
Authors: Norgaard Richard B.
Published: December 2015

Words are integral to thinking and communicating. Words also carry old baggage. The Anthropocene necessitates new thinking and communication at the human–nature interface. Words like progress, natural, and thresholds are pervasive in both scientific and policy discourse, but carry baggage that will likely slow understanding of the Anthropocene and appropriate adaptation. The dynamic systems thinking with emergent properties of ecology needs to replace the efficiency and growth framework of economics. Diversity and resilience are productive and less historically burdened words.
The role of fall season tropical plumes in enhancing Saharan rainfall during the African Humid Period
Authors: Skinner Christopher B. , Poulsen Christopher J.
Published: December 2015

The early Holocene to mid‐Holocene African Humid Period (AHP) is marked by widespread rainfall throughout the present‐day arid Sahara. Here we simulate early Holocene and mid‐Holocene climate with the Community Atmosphere Model version 5 to explore the role of fall season dynamics in driving Saharan rainfall during the AHP. An enhanced summer monsoon during the AHP results in abundant fall season moisture throughout tropical Africa, particularly during the mid‐Holocene. During the fall, extratropical troughs advect tropical moisture toward the Sahara in the form of concentrated plumes of water vapor and extend the Saharan rainy season into October. Fall season tropical plumes contribute up to 30% of annual Saharan rainfall during the mid‐Holocene. Our results suggest that tropical plumes serve as an important mechanism for enhancing Saharan rainfall during the late AHP and that further understanding of changes in tropical plumes through time may provide valuable insights into past African hydroclimate change.
Initial mapping of Mercury's crustal magnetic field: Relationship to the Caloris impact basin
Authors: Hood L. L.
Published: December 2015

Seventy‐eight low‐altitude passes of MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data from August to September of 2014 have been applied to produce an approximate map of the crustal magnetic field at a constant altitude of 80 km covering latitudes of 50°–80°N and longitudes of 160°–330°E. The strongest anomalies are located in the westernmost part of the mapped region just north and northeast of the Caloris impact basin. The strongest single anomaly group lies over a smooth plains unit that extends northward from Caloris. A second anomaly lies on the Odin Formation, interpreted as primary Caloris ejecta. A third broad anomaly also lies over a smooth plains unit, Suisei Planitia. Although many smooth plains on Mercury may have a volcanic origin, a subset of these plains is concentrated around Caloris and could have a dominantly impact origin. It is therefore proposed that many of the Mercurian anomaly sources consist of impact basin ejecta materials.
Modeling Europa's dust plumes
Authors: Southworth B. S. , Kempf S. , Schmidt J.
Published: December 2015

The discovery of Jupiter's moon Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we simulate possible Europa plume configurations, analyze particle number density and surface deposition results, and estimate the expected flux of ice grains on a spacecraft. Due to Europa's high escape speed, observing an active plume will require low‐altitude flybys, preferably at altitudes of 5–100 km. At higher altitudes a plume may escape detection. Our simulations provide an extensive library documenting the possible structure of Europa dust plumes, which can be quickly refined as more data on Europa dust plumes are collected.
A statistical model for seismic hazard assessment of hydraulic‐fracturing‐induced seismicity
Authors: Hajati T. , Langenbruch C. , Shapiro S. A.
Published: December 2015

We analyze the interevent time distribution of hydraulic‐fracturing‐induced seismicity collected during 18 stages at four different regions. We identify a universal statistical process describing the distribution of hydraulic‐fracturing‐induced events in time. The distribution of waiting times between subsequently occurring events is given by the exponential probability density function of the homogeneous Poisson process. Our findings suggest that hydraulic‐fracturing‐induced seismicity is directly triggered by the relaxation of stress and pore pressure perturbation initially created by the injection. Therefore, compared to this relaxation, the stress transfer caused by the occurrence of preceding seismic events is mainly insignificant for the seismogenesis of subsequently occurring events. We develop a statistical model to compute the occurrence probability of hydraulic‐fracturing‐induced seismicity. This model can be used to assess the seismic hazard associated with hydraulic fracturing operations. No aftershock triggering has to be included in the statistical model.
Air moisture control on ocean surface temperature, hidden key to the warm bias enigma
Authors: Hourdin Frédéric , Găinusă‐Bogdan Alina , Braconnot Pascale , Dufresne Jean‐Louis , Traore Aboul‐Khadre , Rio Catherine
Published: December 2015

The systematic overestimation by climate models of the surface temperature over the eastern tropical oceans is generally attributed to an insufficient oceanic cooling or to an underestimation of stratocumulus clouds. We show that surface evaporation contributes as much as clouds to the dispersion of the warm bias intensity in a multimodel simulations ensemble. The models with the largest warm biases are those with the highest surface heating by radiation and lowest evaporative cooling in atmospheric simulations with prescribed sea surface temperatures. Surface evaporation also controls the amplitude of the surface temperature response to this overestimated heating, when the atmosphere is coupled to an ocean. Evaporation increases with temperature both because of increasing saturation humidity and of an unexpected drying of the near‐surface air. Both the origin of the bias and this temperature adjustment point to the key role of near‐surface relative humidity and its control by the atmospheric model.
Recent Hadley cell expansion: The role of internal atmospheric variability in reconciling modeled and observed trends
Authors: Garfinkel Chaim I. , Waugh Darryn W. , Polvani Lorenzo M.
Published: December 2015

Several studies have reported that global climate models underestimate the observed trend in tropical expansion, with the implication that such models are missing key processes of the climate system. We show here that integrations of a chemistry‐climate model forced with observed sea surface temperatures (SSTs), greenhouse gases, and ozone‐depleting substances can produce 1980 to 2009 expansion trends comparable to those found in most reanalyses data products. Correct representation of the SSTs changes is important for the Northern Hemisphere, while correct representation of stratospheric ozone changes is important for the Southern Hemisphere. The ensemble mean trend (which captures only the forced response) is nearly always much weaker than trends in reanalyses. This suggests that a large fraction of the recently observed changes may, in fact, be a consequence of internal atmospheric variability and not a response of the climate system to anthropogenic forcings.
Local finite‐amplitude wave activity as an objective diagnostic of midlatitude extreme weather
Authors: Chen Gang , Lu Jian , Burrows D. Alex , Leung L. Ruby
Published: December 2015

Midlatitude extreme weather events are responsible for a large part of climate‐related damage, yet our understanding of these extreme events is limited, partly due to the lack of a theoretical basis for midlatitude extreme weather. In this letter, the local finite‐amplitude wave activity (LWA) of Huang and Nakamura (2015) is introduced as a diagnostic of the 500 hPa geopotential height for characterizing midlatitude weather events. It is found that the LWA climatology and its variability associated with the Arctic Oscillation agree broadly with the previously reported blocking frequency in the literature. There is a strong seasonal and spatial dependence in the trends of LWA in recent decades. While there is no observational evidence for a hemispheric‐scale increase in wave amplitude, robust trends in wave activity can be identified at the regional scales, with important implications for regional climate change.
In situ observations of flux rope at the separatrix region of magnetic reconnection
Authors: Huang S. Y. , Retino A. , Phan T. D. , Daughton W. , Vaivads A. , Karimabadi H. , Zhou M. , Sahraoui F. , Li G. L. , Yuan Z. G. , Deng X. H. , Fu H. S. , Fu S. , Pang Y. , Wang D. D.
Published: December 2015

We present the first in situ observations of a small‐scale flux rope locally formed at the separatrix region of magnetic reconnection without large guide field. Bidirectional electron beams (cold and hot beams) and density cavity accompanied by intense wave activity substantiate the crossing of the separatrix region. Density compression and one parallel electron beam are detected inside the flux rope. We suggest that this flux rope is locally generated at the separatrix region due to the tearing instability within the separatrix current layer. This observation sheds new light on the 3‐D picture of magnetic reconnection in space plasma.
Enhanced N2 and O2 densities inferred from EISCAT observations of Pc5 waves and associated electron precipitation
Authors: Sydorenko D. , Rankin R. , Yau A. W.
Published: December 2015

An advanced two‐dimensional numerical model of the coupled ionosphere and magnetosphere is used to analyze EISCAT observations of ULF waves that are accompanied by electron precipitation with a wide energy spectrum. The observations show columns of significantly enhanced electron density produced by pulsating precipitation at altitudes between 150 km and 300 km. After each precipitation pulse, the plasma density returns to its initial value within 2 min. Simulations reveal that such a high‐density decay rate cannot be reproduced with the composition of neutrals corresponding to a quiet time provided by the Mass Spectrometer Incoherent Scatter model. To explain the rapid density decay rate using the model of the coupled ionosphere and magnetosphere, the density of nitrogen and oxygen molecules was increased, while the density of oxygen atoms was decreased. The modified neutral densities improved not only the decay rate but also the altitude profile of plasma density which had no F2 layer maximum before the wave and the pulsating precipitation started.
Emission of hydrogen energetic neutral atoms from the Martian subsolar magnetosheath
Authors: Wang X.‐D. , Alho M. , Jarvinen R. , Kallio E. , Barabash S. , Futaana Y.
Published: December 2015

We have simulated the hydrogen energetic neutral atom (ENA) emissions from the subsolar magnetosheath of Mars using a hybrid model of the proton plasma charge exchanging with the Martian exosphere to study statistical features revealed from the observations of the Neutral Particle Detectors on Mars Express. The simulations reproduce well the observed enhancement of the hydrogen ENA emissions from the dayside magnetosheath in directions perpendicular to the Sun‐Mars line. Our results show that the neutralized protons from the shocked solar wind are the dominant ENA population rather than those originating from the pickup planetary ions. The simulation also suggests that the observed stronger ENA emissions in the direction opposite to the solar wind convective electric field result from a stronger proton flux in the same direction at the lower magnetosheath; i.e., the proton fluxes in the magnetosheath are not cylindrically symmetric. We also confirm the observed increasing of the ENA fluxes with the solar wind dynamical pressure in the simulations. This feature is associated with a low altitude of the induced magnetic boundary when the dynamic pressure is high and the magnetosheath protons can reach to a denser exosphere, and thus, the charge exchange rate becomes higher. Overall, the analysis suggests that kinetic effects play an important and pronounced role in the morphology of the hydrogen ENA distribution and the plasma environment at Mars, in general.
Coincidence of heliospheric current sheet and stream interface: Implications for the origin and evolution of the solar wind
Authors: Huang Jia , Liu Yong C.‐M. , Klecker Berndt , Chen Yao
Published: December 2015

In general, the heliospheric current sheet (HCS), which defines the boundary of sunward and antisunward magnetic field, is encased by the slow solar wind. The stream interface (SI) represents the boundary between the solar wind plasmas of different origin and/or characteristics. According to earlier studies using data of low time resolution, the SI and HCS get closer further away from the Sun, and the two structures coincide with each other around 5 AU. In this study, we use STEREO data of a much higher time resolution to reveal an unusual case where the SI and HCS are coincident near 1 AU and separated from the so‐called true sector boundary (TSB) at which the suprathermal electrons change their relative propagation directions. Preliminary analysis suggests that the closed loops in pseudostreamers continually have interchange reconnection with the open‐field lines that lead them, resulting not only in the coincidence of HCS and SI but also in the separation of the TSB from the HCS/SI. We therefore conclude that the interchange reconnection plays an important role in the evolution of slow solar wind.
Effects of solar and geomagnetic activities on the zonal drift of equatorial plasma bubbles
Authors: Huang Chao‐Song , Roddy Patrick A.
Published: December 2015

Equatorial plasma bubbles are mostly generated in the postsunset sector and then move in the zonal direction. Plasma bubbles can last for several hours and move over hundreds of kilometers (even more than 1000 km). In this study, we use measurements of ion density by the Communication/Navigation Outage Forecasting System satellite to determine the orbit‐averaged drift velocity of plasma bubbles. The objective of the study is to identify the dependence of the bubble drift on the solar radio flux and geomagnetic activities. In total, 5463 drift velocities are derived over May 2008 to April 2014, and a statistical analysis is performed. The average pattern of the bubble drift is in good agreement with the zonal drift of the equatorial F region plasma. The zonal drift velocity of plasma bubbles increases with the solar radio flux. However, the increase shows different features at different local times. Geomagnetic activities cause a decrease of the eastward drift velocity of plasma bubbles, equivalent to the occurrence of a westward drift, through disturbance dynamo process. In particular, the decrease of the eastward drift velocity appears to become accelerated when the Dst index is smaller than −60 nT or Kp is larger than 4.
Generation of shear Alfvén waves by repetitive electron heating
Authors: Wang Y. , Gekelman W. , Pribyl P. , Van Compernolle B. , Papadopoulos K.
Published: December 2015

ELF/ULF waves are powerful tools for submarine communication, geophysical mapping, and radiation belt remediation. However, due to their large wavelength (on the order of 102–104 km or 0.1–10 RE) it is difficult to launch them using ground‐based antennas. Alternatively, these waves can be generated by modulating the temperature of the ionosphere using ground‐based HF transmitters. The paper reports a detailed laboratory study on the generation of shear Alfvén waves by repetitive electron heating. The experiments were conducted on the large plasma device at University of California, Los Angeles. In the experiment, 10 pulses of high‐power microwaves (250 kW, 1 µs each) near the plasma frequency modulated at a variable fraction between 0.1 and 1.0 of fci are launched transverse to the background field. In addition to bulk electron heating the interaction generates a population of fast electrons in the tail of the distribution function. The field‐aligned current carried by the fast electrons acts as an antenna that radiates shear Alfvén waves. It is demonstrated that a shear Alfvén wave at a controllable, arbitrary frequency (f < fci) can be coherently driven by the repetitive microwave pulses. The radiation pattern and power dependence of the virtual antenna are also presented. The experiments provide a novel virtual antenna concept relevant to the equatorial region where the Earth's magnetic field is horizontal and the field‐aligned plasma density gradient is small. The results are important to design of new mobile ionospheric heaters for equatorial and middle latitude locations.
Evolution of the rheological and microstructural properties of olivine aggregates during dislocation creep under hydrous conditions
Authors: Tasaka Miki , Zimmerman Mark E. , Kohlstedt David L.
Published: December 2015

Since hydrogen plays an important role in dynamic processes in Earth's mantle, we conducted torsion experiments to shear strains of 0.6 to 5.0 on Fe‐bearing olivine aggregates [(Mg0.5Fe0.5)2SiO4: Fo50] under hydrous conditions at T = 1200°C and P = 300 MPa. We deformed samples to high enough strains that a steady state microstructures were achieved, which allowed us to investigate the evolution of both the rheological and microstructural properties. The stress exponent of n ≈ 5.0 and the grain size exponent of p ≈ 0 determined by fitting the strain rate, stress, and grain size data indicate that our samples deformed by dislocation creep. Fourier transform infrared spectroscopy measurements on embedded olivine single crystals demonstrated that our samples were saturated with hydrogen during the deformation experiments. The lattice preferred orientation (LPO) of olivine changes as a function of strain due to competition among three slip systems: (010)[100], (100)[001], and (001)[100]. Observed strain weakening can be attributed to geometrical softening associated with development of LPO, which reduces the stress by ~1/3 from its peak value in constant strain rate experiments. The geometrical softening coefficient determined in this study is an important constraint for modeling and understanding dynamical processes in the upper mantle under hydrous conditions.