bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Performance Thin-Layer Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry for Identifying Neutral Lipids and Sphingolipids in Complex Samples
Authors: Jarne Carmen , Savirón María , Lapieza María Pilar , Membrado Luis , Orduna Jesús , Galbán Javier , Garriga Rosa , Morlock Gertrud Elisabeth , Cebolla Vicente Luis
Published: March 2018

High-performance thin-layer chromatography was directly combined with electrospray mass spectrometry (ESI-MS) for structural identification issues below the level of lipid classes in complex samples through a portable, automated, elution-based interface. For samples as diverse as biodiesel and human plasma, separation conditions using Automated Multiple Development were selected in each case to provide lipid classes as zones narrow enough to ensure a direct transfer of them to ESI-MS. The respective zone of interest can be selected at will. ESI+ spectra of neutral lipids and sphingolipids showed sodium adducts when recorded from the plate. By using the described technique and ion-trap technology, the respective sodium adducts were fragmented. Sodium remained as the charge of the fragment ions and, thus, was useful for their structural identification through MSn. In this way, composition profiles of each class by ESI+-MS, and further identification of individual lipids and the molecular species belonging to each of them, were obtained by MS/MS and/or high-resolution MS. Thus, mono and diacylglycerides in ESI+ and fatty acids (in ESI−) were identified as low-concentration impurities in a fatty acid methyl ester–based biodiesel sample. Likewise, molecular species of sphingomyelins and globotriaosylceramides were unequivocally identified in human plasma samples.
Hegel, the Struggle for Recognition, and Robots
Authors: Gertz Nolen ,   Philosophy Documentation Center
Published: March 2018

While the mediational theories of Don Ihde and Peter-Paul Verbeek have helped to uncover the role that technologies play in ethical life, the role that technologies play in political life has received far less attention. In order to fill in this gap, I turn to the mediational theory of Hegel. Hegel shows how understanding the mediated nature of experience is vital to understanding the development of political life. Through examples found in the military, in particular concerning the relationship between explosive ordnance detonation (EOD) soldiers and robots, I illustrate how Hegel’s analysis of the “struggle for recognition” can be used to understand human-technology relations from a political perspective. This political perspective can consequently help us to appreciate how technologies come to have a role in political life through our ability to experience solidarity with technology. Solidarity is experienced by users due to the recognition of technologies as serving roles in society that I describe as functionally equivalent to the social roles of the user. The realization of this functional equivalence allows users to learn how they are perceived and respected by society through the experience of how functionally equivalent technologies are perceived and respected. I conclude by focusing on the importance of understanding functional equivalence in design, as well as in the case of the Dallas Police Department having turned an EOD robot from a life-saving to a life-taking device. These examples show why Hegel is necessary for helping us to understand the political significance of recognizing and of misrecognizing technologies.
RELAÇÕES TEMPORAIS NA NARRATIVA INFANTIL EM DADOS DE FALA DE PORTUGUÊS BRASILEIRO
Authors: Soares Simone Mendonça , Silva Bibiana Cardoso da
Published: March 2018

Este estudo investiga o padrão de uso dos recursos linguísticos utilizados por crianças de 3 a 6 anos para expressar relações temporais em narrativas orais. As narrativas sob análise são provenientes de um banco de dados constituído pela produção oral de 60 crianças entre 3 e 6 anos de idade dos municípios de Novo Hamburgo e Porto Alegre no Rio Grande do Sul. Os dados utilizados são de 8 destas crianças, 4 na faixa de 3 a 4 anos de idade e 4 na faixa de 5 a 6 anos de idade. A análise dos dispositivos que compõem o sistema temporal nas narrativas mostrou que, de forma geral, as crianças menores estruturam mais a sequencialidade dos eventos, enquanto que as crianças maiores já dominam de forma qualificada, ou seja, com maior articulação de dispositivos gramaticais e lexicais, tanto a sequencialidade quanto a simultaneidade entre os eventos da narrativa.
“MURIÇOCA” OU “MARUIM”? DESIGNAÇÕES PARA “PERNILONGO” NO NORTE E NORDESTE DO BRASIL
Authors: Silva Jane Keli Almeida da , Souza Cemary Correia de
Published: March 2018

O presente estudo buscou investigar como os contatos linguísticos e culturais com outros povos, sobretudo os indígenas, contribuíram para a formação do léxico do Português Brasileiro. Para tal, o corpus foi constituído a partir dos resultados da aplicação do Questionário Semântico-Lexical (QSL-ALiB), relacionada à área temática da Fauna, decorrentes das respostas à questão de número 88, respectivamente: “... aquele inseto pequeno, de perninhas compridas, que canta no ouvido das pessoas de noite?”. Concentrou-se a pesquisa a três localidades do interior do estado de Alagoas – União dos Palmares, Santana do Ipanema e Arapiraca – e em igual número localidades do interior do Acre – Soure, Marabá e Itaituba –. Das 07 variantes registradas, 04 são oriundas do tupi (carapanã, maruim, muriçoca e muruanha) com maior produtividade no norte, confirmando a vitalidade do substrato tupi no léxico dos informantes. As outras 03 variantes (pernilongo/pernalonga e mosquito), de base portuguesa, concentram-se, sobretudo, na região nordeste.
OS MITOS DE UMA LÍNGUA (DES) CONHECIDA
Authors: Lussani Brendom Da Cunha , Santos Bruna Rafaela dos , Fonseca Camila Cristina Martins , Forneck Kári Lúcia
Published: March 2018

A língua portuguesa, da mesma forma como o ser humano, evolui no curso da história, afinal, só existe uma língua porque existem falantes que a mantém em uso. Mas,há uma cultura muito forte da predominância da gramática normativa como única abordagem linguística válida, que confunde a concepção de língua e induz ao preconceito linguístico. A partir disso, criam-se mitos que disseminam ainda mais o preconceito, sem se darem conta disso. Nesse sentido, este artigo, baseando-se em uma pesquisa quantitativa, teve como objetivo analisar a percepção de língua que os participantes possuem, e verificar se esses mitos realmente fazem parte de suas percepções. Para tanto, foi aplicado um questionário no Google Formulários no qual 143 participantes avaliaram enunciados que reproduzem concepções de preconceito linguístico. A partir da análise dos dados, observou-se que existem muitos conceitos distorcidos sobre a língua portuguesa que contribuem para a propagação do chamado preconceito linguístico.
CONCEPÇÕES DE APRENDIZAGEM DO PROFESSOR DE LÍNGUAS: QUANDO O DISCURSO SE REFLETE NA PRÁTICA
Authors: Santos Andressa Dawwed dos , Cecchin Anidene Da Siqueira
Published: March 2018

Este trabalho visa reportar a análise das concepções de aprendizagem subjacentes no discurso de uma professora da disciplina de Estágio Supervisionado, do curso de Letras – Inglês da UFSM, ao descrever sua prática. Como aporte teórico, adotamos as teorias cognitivista (CHOMSKY, 1981; 1986; 1987; 1988; 1995; PIAGET, 1976, 1987, 1988) e sócio-histórico-cultural (VYGOTSKY, 1931; 1934, 2001). Analisamos a transcrição de uma entrevista semiestruturada com a professora. Para isso, recorremos à Análise Crítica do Discurso (ACD) (FAIRCLOUGH, 2003) e adaptamos de Ticks (2009) três categorias para discutir os dados: 1) identificação da perspectiva; 2) contexto nos quais a perspectiva é vivenciada pela participante em relação ao contexto escolar e 3) papéis sociais do aluno e do professor. Os resultados revelaram dois momentos: o primeiro, com foco na descrição da formação inicial da professora, evidenciando a perspectiva cognitivista; e o segundo com foco no seu relato como formadora, demonstrando a teoria sócio-histórico-cultural.
AS MEMÓRIAS DA FAVELA DE CONCEIÇÃO EVARISTO
Authors: Canto Daniela Schwarcke do , Alós Anselmo Peres
Published: March 2018

Não há (trata-se de resenha).
Inclusão de alunos com deficiências em escolas da rede estadual: acessibilidade e adaptações estruturais
Authors: Castro Gisélia Gonçalves de , Abrahão Cesar Augusto França , Nunes Ângela Xavier e , Nascimento Lilian Cristina Gomes do , Figueiredo Glória Lúcia Alves
Published: March 2018

Estima-se que existam no Brasil cerca de seis milhões de crianças e jovens com necessidades educacionais especiais, para um contingente oficial de matrículas em torno de 500 mil alunos, considerando o conjunto de matrículas em todos os tipos de recursos disponíveis, desde escolas especiais até escolas e classes comuns. Grande maioria dos alunos com necessidades educacionais especiais encontra-se hoje fora da escola, o que configura muito mais uma exclusão generalizada da escola, a despeito da anterior retórica da integração e/ou da recente proposta de inclusão escolar. O estudo teve como objetivo investigar a acessibilidade e adaptações estruturais em 14 escolas estaduais de um município mineiro e identificar a prevalência de alunos com deficiência. Estudo transversal, e descritivo através de um questionário e registro fotográfico. Do total de alunos matriculados, 111 possuem algum tipo de deficiência, com prevalência no sexo masculino, idade média de 13,84 ± 5,19, onde 65,77% com deficiência mental. Em relação às adaptações estruturais, 92,86% possuem rampas nas entradas das escolas, 50 % vaso sanitário adaptado com barras de segurança e acesso com corrimãos, 28,57% piso antiderrapante, 21,43% mobiliário adaptado e rampas na entrada das salas de aula. Apenas 14,29% constam com altura ideal da pia e da saboneteira, em nenhuma foi encontrado banheiros com espelhos inclinados.Conclui-se indubitavelmente que há necessidade de melhoria das condições de acessibilidade na rede educacional. Faz necessária implantação de medidas adaptativas com o intuito de tornar cada vez mais presente a inclusão e acessibilidade a pessoa com necessidades especiais.
Considerações preliminares sobre o ensino da natação para autistas
Authors: Lira Neto Joaquim Francisco
Published: March 2018

O presente trabalho tem a intenção de delinear diretrizes preliminares a partir das quais pode ser elaborado um plano de ensino de natação voltado especificamente para autistas. Embora já existam publicações que tomam como objeto de estudo a prática da modalidade esportiva em questão por autistas, ainda são poucos os estudos que buscam superar os parâmetros do que pode ser considerado como o ensino tradicional da natação, visando atender às características próprias deste público. Tal superação pode ocorrer através das contribuições de métodos já consagrados, como o Método Halliwick, conhecido pelo ensino da natação para deficientes, e o Método ABA, amplamente utilizado nos casos de Transtornos do Espectro Autista (TEA). Após a análise aqui empreendida, é possível considerar que os métodos abordados fornecem subsídios para um ensino de natação que, além de aceitar autistas, esteja voltado para a compreensão e para o atendimento de suas necessidades, como é esperado de uma prática inclusiva.
O Atendimento Pedagógico Domiciliar de alunos que não podem frequentar fisicamente a escola por motivos de saúde: Revisão Sistemática das investigações realizadas entre 2002 e 2015
Authors: Moreira Geraldo Eustáquio , Salla Helma
Published: March 2018

Esta investigação se relaciona ao atendimento pedagógico domiciliar (APD) no Brasil. Analisou-se as publicações existentes nas bases de dados nacionais sobre o APD, de 2002 a 2015. Especificamente, foram analisados os dados referentes às pesquisas, como o ano de publicação, a modalidade de texto científico, a unidade da federação, o foco das pesquisas e as metodologias utilizadas, observando as categorias e as subcategorias relacionadas ao contexto do APD. Utilizou-se as palavras-chaves dos resumos para a construção de uma lista de descritores presentes nos textos relacionados ao APD, mediante a busca de dados sobre as citações e o fator h. A pesquisa bibliográfica com abordagem quantiqualitativa de investigação foi utilizada para a análise dos trabalhos publicados no portal CAPES e no site Google Acadêmico. O uso da frase “atendimento pedagógico domiciliar” foi utilizado como parâmetro e foram selecionadas 277 pesquisas, quando encontraram-se 10 trabalhos relacionados ao APD. Foram utilizados o software Harzing’s Publish, o Mendeley, o OringinPro8 e o Word clud art para as análises e, para os resultados mais significativos, foram feitas as nuvens de tags. Os resultados demostraram que existe, no Brasil, poucos pesquisadores preocupados com os contextos e a efetivação do APD; que existe formação inicial e continuada na área do APD, mesmo que de forma pontual, sendo a maioria na região Sul; que o índice h de muitos trabalhos era inexistente ou zero, sendo 2 o maior, o que demonstra uma pesquisa científica ainda pouco significativa na área do APD. Neste sentido, existe uma área de investigação crescente relacionada ao APD, que possibilita o crescimento da formação e informação de uma sociedade preocupada com o esse tipo de atendimento pedagógico.
Editorial – Revista Educação Especial
Authors: Schmidt Carlo , Menezes Eliana Pereira de , Berni Clenio Perlin
Published: March 2018

Editorial
Edge Bounds and Degeneracy of Triangle-Free Penny Graphs and Squaregraphs
Authors: Eppstein David
Published: March 2018

We show that triangle-free penny graphs have degeneracy at most two, and that both triangle-free penny graphs and squaregraphs have at most $\min\bigl(2n-\Omega(\sqrt n),2n-D-2\bigr)$ edges, where $n$ is the number of vertices and $D$ is the diameter of the graph.
A Comparative Study of Wordsworth and Sepehri`s Poetry in the Light of Ibn Arabi`s Philosophy
Authors: Matin Parsa Laiya
Published: March 2018

Sohrab Sepehri and William Wordsworth’s poems, have repeatedly been compared as they both reflect Pantheism and Emerson’s Over-Soul, yet they have never been studied in the light of Ibn Arabi’s Philosophy. The theory of Constant Immanence or renewal of creation expressed by Ibn Arabi can be regarded as an umbrella term to read the selected poems of Sepehri and Wordsworth and detect the similarities between these poets of two distinct milieu. Ibn Arabi’s innovative ideas of constantly renewing creation of the cosmos, the relationship between Man and Nature, Perfect Man and the love of religion have been depicted impressively centuries later in Sepehri’s and Wordsworth’s works. There is a wide tendency to compare the poems of these two poets of different milieu due to their special outlook to nature and their very individualistic worlds and their wide acceptance by both elite and common readers of poetry.
Pauses by Student and Professional Translators in Translation Process
Authors: Noor Rosa Rusdi , Sinar T. Silvana , Ibrahim-Bell Zubaidah , Setia Eddy
Published: March 2018

Translation as a process of meaning making activity requires a cognitive process one of which is realized in a pause, a temporary stop or a break indicating doing other than typing activities in a certain period of translation process. Scholars agree that pauses are an indicator of cognitive process without which there will never be any translation practices. Despite such agreement, pauses are debatable as well, either in terms of their length or in terms of the activities managed by a translator while taking pauses. This study, in particular, aims at finding out how student translators and professional translators managed the pauses in a translation process. This was a descriptive research taking two student translators and two professional translators as the participants who were asked to translate a text from English into bahasa Indonesia. The source text (ST) was a historical recount text entitled ‘Early History of Yellowstone National Park’ downloaded from http://www.nezperce.com/yelpark9.html composed of 230-word long from English into bahasa Indonesia. The data were collected using Translog protocols, think aloud protocols (TAPs) and screen recording. Based on the data analysis, it was found that student translators took the longest pauses in the drafting phase spent to solve the problems related to finding out the right equivalent for the ST words or terms and to solve the difficulties encountered in encoding their ST understanding in the TL; meanwhile, professional translators took the longest pauses in the pos-drafting phase spent to ensure whether their TT had been natural and whether their TT had corresponded to the prevailing grammatical rules of the TL.
The Mythopoetics of Chinua Achebe’s Anthills of the Savannah
Authors: Aning John , Gbolo Sanka Confidence , Elsbend Kofigah Francis
Published: March 2018

The objective of this paper is to investigate how Chinua Achebe uses myth making as an attempt to address the leadership problem of his country, Nigeria. Many writers have identified leadership as the greatest problem of many countries in Africa. Consequently, Achebe uses symbolism and a language full of violence to portray the levels of corruption and abuse of power in the novel.  In this paper, we present a myth criticism of Achebe’s Anthills of the Savannah by looking at how the novelist deconstructs Biblical and traditional stories to show that women should be given a greater political role alongside men to chart a new course of development. Achebe’s novel is dominated by the myth of the Pillar of Fire which he takes from the Bible and the Idemili myth which he takes from the traditions of his people. At the end of the deconstruction of these two myths, the only viable alternative left is the all-inclusive group led by the priestess of Idemili and hope is finally enshrined in the baby girl Amaechina.
Omission in Possible: the Forensic Linguistics Autopsy of the Court Interpreting Praxis
Authors: Jati Murtaya Taufiq , Triyono Sulis
Published: March 2018

To have a proportional rendition, an interpreter has to deal with the dilemmatic decision of technique employment. In fact, in a case of court interpreting there are a bunch of oppressive moments, since its impact is exclusively stroke on the hearings’ route; and generally in the law enforcement constitution. For that fundamental circumstance, this article links the perspectives to achieve the goal how the court interpreting should be held from the notion of one of the interpreting strategies, namely the omission and the conceptual perspective of forensic linguistics. Here, this article reviews some points of view from both sides; and scrutinizes what lies beneath so the findings are beneficial for the court interpreting practices and studies. This article articulates that the omissions are taken for the sake of the prosecution flawless systemic process. Thus, the interpreter should be aware of the nuance of the two main conditions of the witness examination session i.e. the examination-in-chief and the cross-examination. More importantly, the forensic linguistics considers this as the effort in a working condition of the court interpreter to keep the most proportional judicial atmosphere in balance in terms of symmetrical and asymmetrical relation. This article then proposes the significance of having more knowledge on forensic linguistics for a court interpreter in doing and learning court interpreting.
Narratives of Displacement: The Challenges of Motherhood and Mothering in semi-fictional works by Laura Pariani, Mary Melfi, and Donatella Di Pierantonio
Authors: Rorato Laura
Published: March 2018

This article analyses the representation of the impact of migration on family dynamics in three autobiographical works: Laura Pariani’s Il piatto dell’angelo (2013), Mary Melfi’s Italy Revisited. Conversations with my Mother (2009), and Antonella Di Pietrantonio’s Mia madre è un fiume (2011). All three authors were directly or indirectly affected by the wave of emigration that took place in Italy between the end of the 19th century and the first half of the 20th century. Pariani extends her observations to the present by focusing also on those South American women who are currently moving to Italy to work as cares for old people, often leaving their families behind. Motherhood and mothering are central themes in all three books. These works problematise the patriarchal notion of motherhood and highlight the need to move towards alternative concepts of motherhood that do not imply the subordination of women. Additionally, this article offers a reflection on the role that creative writing can play in challenging some of the most engrained stereotypes, such as those of the good mother versus the bad mother, partially related to our Christian tradition. Building on Podnieks and O’Reilly’s notion of “maternal texts” (1-2), this article argues that through fiction women are less inhibited in exploring the thornier aspects of motherhood as a social construction than they seem to be in everyday life.
Breast cancer identification via modeling of peripherally circulating miRNAs
Authors: Cui Xiaomeng , Li Zhangming , Zhao Yilei , Song Anqi , Shi Yunbo , Hai Xin , Zhu Wenliang
Published: March 2018

Prolonged life expectancy in humans has been accompanied by an increase in the prevalence of cancers. Breast cancer (BC) is the leading cause of cancer-related deaths. It accounts for one-fourth of all diagnosed cancers and affects one in eight females worldwide. Given the high BC prevalence, there is a practical need for demographic screening of the disease. In the present study, we re-analyzed a large microRNA (miRNA) expression dataset (GSE73002), with the goal of optimizing miRNA biomarker selection using neural network cascade (NNC) modeling. Our results identified numerous candidate miRNA biomarkers that are technically suitable for BC detection. We combined three miRNAs (miR-1246, miR-6756-5p, and miR-8073) into a single panel to generate an NNC model, which successfully detected BC with 97.1% accuracy in an independent validation cohort comprising 429 BC patients and 895 healthy controls. In contrast, at least seven miRNAs were merged in a multiple linear regression model to obtain equivalent diagnostic performance (96.4% accuracy in the independent validation set). Our findings suggested that suitable modeling can effectively reduce the number of miRNAs required in a biomarker panel without compromising prediction accuracy, thereby increasing the technical possibility of early detection of BC.
FGFR2 amplification is predictive of sensitivity to regorafenib in gastric and colorectal cancers in vitro
Authors: Cha Yongjun , Kim Hwang‐Phill , Lim Yoojoo , Han Sae‐Won , Song Sang‐Hyun , Kim Tae‐You
Published: March 2018

Although regorafenib has demonstrated survival benefits in patients with metastatic colorectal and gastrointestinal stromal tumors, no proven biomarker has been identified for predicting sensitivity to regorafenib. Here, we investigated preclinical activity of regorafenib in gastric and colorectal cancer cells to identify genetic alterations associated with sensitivity to regorafenib. Mutation profiles and copy number assays of regorafenib target molecules indicated that amplification of fibroblast growth factor receptor 2 (FGFR2) was the only genetic alteration associated with in vitro sensitivity to regorafenib. Regorafenib effectively inhibited phosphorylation of FGFR2 and its downstream signaling molecules in a dose‐dependent manner and selectively in FGFR2‐amplified cells. Regorafenib induced G1 arrest (SNU‐16, KATO‐III) and apoptosis (NCI‐H716); however, no significant changes were seen in cell lines without FGFR2 amplification. In SNU‐16 mice xenografts, regorafenib significantly inhibited tumor growth, proliferation, and FGFR signaling compared to treatment with control vehicle. Regorafenib effectively abrogates activated FGFR2 signaling in FGFR2‐amplified gastric and colorectal cancer and, therefore, might be considered for integration into treatment in patients with FGFR2‐amplified gastric and colorectal cancers.
The Impact of Variable Phytoplankton Stoichiometry on Projections of Primary Production, Food Quality, and Carbon Uptake in the Global Ocean
Authors: Kwiatkowski Lester , Aumont Olivier , Bopp Laurent , Ciais Philippe
Published: March 2018

Ocean biogeochemical models are integral components of Earth system models used to project the evolution of the ocean carbon sink, as well as potential changes in the physical and chemical environment of marine ecosystems. In such models the stoichiometry of phytoplankton C:N:P is typically fixed at the Redfield ratio. The observed stoichiometry of phytoplankton, however, has been shown to considerably vary from Redfield values due to plasticity in the expression of phytoplankton cell structures with different elemental compositions. The intrinsic structure of fixed C:N:P models therefore has the potential to bias projections of the marine response to climate change. We assess the importance of variable stoichiometry on 21st century projections of net primary production, food quality, and ocean carbon uptake using the recently developed Pelagic Interactions Scheme for Carbon and Ecosystem Studies Quota (PISCES‐QUOTA) ocean biogeochemistry model. The model simulates variable phytoplankton C:N:P stoichiometry and was run under historical and business‐as‐usual scenario forcing from 1850 to 2100. PISCES‐QUOTA projects similar 21st century global net primary production decline (7.7%) to current generation fixed stoichiometry models. Global phytoplankton N and P content or food quality is projected to decline by 1.2% and 6.4% over the 21st century, respectively. The largest reductions in food quality are in the oligotrophic subtropical gyres and Arctic Ocean where declines by the end of the century can exceed 20%. Using the change in the carbon export efficiency in PISCES‐QUOTA, we estimate that fixed stoichiometry models may be underestimating 21st century cumulative ocean carbon uptake by 0.5–3.5% (2.0–15.1 PgC).
Regional Variation in Gravel Riverbed Mobility, Controlled by Hydrologic Regime and Sediment Supply
Authors: Pfeiffer Allison M. , Finnegan Noah J.
Published: March 2018

The frequency and intensity of riverbed mobility are of paramount importance to the inhabitants of river ecosystems as well as to the evolution of bed surface structure. Because sediment supply varies by orders of magnitude across North America, the intensity of bedload transport varies by over an order of magnitude. Climate also varies widely across the continent, yielding a range of flood timing, duration, and intermittency. Together, the differences in sediment supply and hydroclimate result in diverse regimes of bed surface stability. To quantitatively characterize this regional variation, we calculate multidecadal time series of estimated bed surface mobility for 29 rivers using sediment transport equations. We use these data to compare predicted bed mobility between rivers and regions. There are statistically significant regional differences in the (a) exceedance probability of bed‐mobilizing flows (W* > 0.002), (b) maximum bed mobility, and (c) number of discrete bed‐mobilizing events in a year.
ISR Spectra Simulations With Electron‐Ion Coulomb Collisions
Authors: Longley William J. , Oppenheim Meers M. , Fletcher Alex C. , Dimant Yakov S.
Published: March 2018

Incoherent scatter radars (ISR) rely on Thomson scattering of very high frequency or ultrahigh frequency radio waves off electrons in the ionosphere and measure the backscattered power spectra in order to estimate altitude profiles of plasma density, electron temperature, ion temperature, and ion drift speed. These spectra result from the collective behavior of coupled ion and electron dynamics, and, for most cases, existing theories predict these well. However, when the radar points nearly perpendicular to the Earth's magnetic field, the motion of the plasma across the field lines becomes complex and Coulomb collisions between electrons and ions become important in interpreting ISR measurements. This paper presents the first fully kinetic, self‐consistent, particle‐in‐cell simulations of ISR spectra with electron‐ion Coulomb collisions. We implement a grid‐based Coulomb collision algorithm in the Electrostatic Parallel Particle‐in‐Cell simulator and obtain ISR spectra from simulations both with and without collisions. For radar directions greater than 5° away from perpendicular to the magnetic field, both sets of simulations match collisionless ISR theory well. For angles between 3° and 5°, the collisional simulation is well described by a simplified Brownian motion collision process. At angles less than 3° away from perpendicular the Brownian motion model fails, and the collisional simulation qualitatively agrees with previous single particle simulations. For radar directions exactly perpendicular to the magnetic field the simulated collisional spectra match those from the Brownian motion collision theory, in agreement with previous single particle simulations.
Depressurization‐Induced Fines Migration in Sediments Containing Methane Hydrate: X‐Ray Computed Tomography Imaging Experiments
Authors: Han Gyeol , Kwon Tae‐Hyuk , Lee Joo Yong , Kneafsey Timothy J.
Published: March 2018

Depressurization of hydrate‐bearing sediments (HBS) can cause the movement of fine particles, and in turn, such fines migration affects fluid flow and mechanical behavior of sediments, ultimately affecting long‐term hydrocarbon production and wellbore stability. This study investigated how and to what extent depressurization of HBS causes fines migration using X‐ray computed tomography (CT) imaging. Methane hydrate was synthesized in sediments with 10% fines content (FC), composed of sands with silt and/or clay, and the hydrate‐bearing samples were stepwisely depressurized while acquiring CT images. The CT images were analyzed to quantify the spatial changes in FC in the host sediment and thus to capture the fines migration during depressurization. It was found that the FC changes began occurring from the hydrate dissociation regions. This confirms that the multiphase flow caused by depressurization accompanies fines migration. Depressurization of HBS with a hydrate saturation of ~20–40% caused FC reduction from ~10% to ~6–9%, and the extent of fines migration differed with the particle sizes of the host sands and the types of fines. It was found that fines migration was more pronounced with coarse sands and with silty fines. Such observed level of FC reduction is estimated to increase sediment permeability by several factors based on the Kozeny‐type permeability model. Our results support the notion that the extent of fines migration and its effect on fluid flow behavior need to be assessed in consideration of physical properties of host sediment and fine particles to identify optimum depressurization strategies.
Active Seafloor Seepage Along Hydraulic Fractures Connected to Lateral Stress From Salt‐Related Rafting: Regab Pockmark, Congo Fan
Authors: Wenau S. , Spiess V.
Published: March 2018

Seafloor seepage is a widespread phenomenon within salt‐influenced basins as the deformation provides pathways for hydrocarbons to reach the seafloor. However, only minor attention has been given to the distal parts of such systems where the impact of salt tectonic deformation is relatively unpronounced. The stress put on the sedimentary column by moving salt on a continental margin may influence fluid flow systems even outside of the salt province. This stress may lead to overpressure formation within reservoirs and determine the orientation of overpressure‐induced fractures. Seepage in the Congo Fan has been discovered in such a distal position at the Regab pockmark, about 35 km west of the salt front, and its geology and biology have been studied extensively in recent years. We present high‐resolution multichannel seismic data from the Regab pockmark that reveal the underlying migration pathways from a buried channel flank 300 m below seafloor to the seafloor via hydraulic fractures in the sealing overburden. Local doming of the reservoir and the remobilization and uplift of sedimentary strata along the migration pathways are interpreted as the result of overpressure within the reservoir. The orientation of the hydraulic fractures is WSW‐ENE, and the fracture outline corresponds to the area of most intense seepage activity within the seafloor pockmark. Along with a similar orientation of other fractures in the vicinity, we propose that this alignment is due to the stress imposed on the sedimentary column in the fan by the seaward moving salt and rafting sedimentary packages of the salt province further east.
Hydrologically Induced Karst Deformation: Insights From GPS Measurements in the Adria‐Eurasia Plate Boundary Zone
Authors: Serpelloni E. , Pintori F. , Gualandi A. , Scoccimarro E. , Cavaliere A. , Anderlini L. , Belardinelli M. E. , Todesco M.
Published: March 2018

We apply a blind source separation algorithm to the ground displacement time series recorded at continuous Global Positioning System (GPS) stations in the European Eastern Alps and Northern Dinarides. As a result, we characterize the temporal and spatial features of several deformation signals. Seasonal displacements are well described by loading effects caused by Earth surface mass redistributions. More interestingly, we highlight a horizontal, nonseasonal, transient deformation signal, with spatially variable amplitudes and directions. The stations affected by this signal reverse the sense of movement with time, implying a sequence of dilatational and compressional deformation that is oriented normal to rock fractures in karst areas. The temporal evolution of this deformation signal is correlated with the history of cumulated precipitations at monthly time scales. This transient horizontal deformation can be explained by pressure changes associated with variable water levels within vertical fractures in the vadose zones of karst systems. The water level changes required to open or close these fractures are consistent with the fluctuations of precipitation and with the dynamics of karst systems.
Effects of Melt Percolation on Zn Isotope Heterogeneity in the Mantle: Constraints From Peridotite Massifs in Ivrea‐Verbano Zone, Italian Alps
Authors: Huang Jian , Chen Sha , Zhang Xing‐Chao , Huang Fang
Published: March 2018

We determined Zn isotopic compositions of 21 orogenic peridotites from the Baldissero and Balmuccia peridotite massifs in Ivrea‐Verbano Zone, Italian Alps, to investigate Zn isotope behaviors during partial melting and melt percolation in the mantle. The samples include lherzolites, harzburgites, and dunites. Lherzolites are strongly depleted in light rare earth element relative to middle and heavy rare earth element with (La/Sm)PM from 0.009 to 0.265 and (La/Yb)PM from 0.003 to 0.125, which can be explained by 5–15% fractional melting of a primitive mantle source. Harzburgites and dunites with nearly identical Mg# (molar 100 * Mg/(Mg + Fe) = 90.2–91.0) have (La/Sm)PM and (La/Yb)PM higher than but Zn contents similar to or lower than those of the parental lherzolites, suggesting that they were influenced by Zn‐depleted silicate melt percolation. Lherzolites have δ66Zn from 0.13 to 0.27‰ showing no correlations with indicators of melt extraction (e.g., Al2O3, Mg#, and La/Yb) and Zn contents. Three sulfide melt‐affected lherzolites show similar δ66Zn to the other normal ones. These observations indicate that 5–15% partial melting and sulfide melt percolation cause limited Zn isotope variations in the mantle. The metasomatic harzburgites and dunites display high δ66Zn (up to 0.46‰) negatively correlated with Zn contents. Such correlations are attributed to kinetic effect during silicate melt percolation, whereby 64Zn preferentially diffuses out from mantle minerals (e.g., olivine) to the percolating silicate melts. A diffusion model suggests that the negative correlation between δ66Zn and Zn contents in dunites can be explained by an empirical βZn (i.e., βZn‐exponent in D66Zn/D64Zn = (m64Zn/m66Zn)βZn) of 0.05–0.06 in olivine.
The Microphysical Properties of Convective Precipitation Over the Tibetan Plateau by a Subkilometer Resolution Cloud‐Resolving Simulation
Authors: Gao Wenhua , Liu Liping , Li Jian , Lu Chunsong
Published: March 2018

The microphysical properties of convective precipitation over the Tibetan Plateau are unique because of the extremely high topography and special atmospheric conditions. In this study, the ground‐based cloud radar and disdrometer observations as well as high‐resolution Weather Research and Forecasting simulations with the Chinese Academy of Meteorological Sciences microphysics and four other microphysical schemes are used to investigate the microphysics and precipitation mechanisms of a convection event on 24 July 2014. The Weather Research and Forecasting‐Chinese Academy of Meteorological Sciences simulation reasonably reproduces the spatial distribution of 24‐hr accumulated rainfall, yet the temporal evolution of rain rate has a delay of 1–3 hr. The model reflectivity shares the common features with the cloud radar observations. The simulated raindrop size distributions demonstrate more of small‐ and large‐size raindrops produced with the increase of rain rate, suggesting that changeable shape parameter should be used in size distribution. Results show that abundant supercooled water exists through condensation of water vapor above the freezing layer. The prevailing ice crystal microphysical processes are depositional growth and autoconversion of ice crystal to snow. The dominant source term of snow/graupel is riming of supercooled water. Sedimentation of graupel can play a vital role in the formation of precipitation, but melting of snow is rather small and quite different from that in other regions. Furthermore, water vapor budgets suggest that surface moisture flux be the principal source of water vapor and self‐circulation of moisture happen at the beginning of convection, while total moisture flux convergence determine condensation and precipitation during the convective process over the Tibetan Plateau.
A Simple Ensemble Simulation Technique for Assessment of Future Variations in Specific High‐Impact Weather Events
Authors: Taniguchi Kenji
Published: March 2018

To investigate future variations in high‐impact weather events, numerous samples are required. For the detailed assessment in a specific region, a high spatial resolution is also required. A simple ensemble simulation technique is proposed in this paper. In the proposed technique, new ensemble members were generated from one basic state vector and two perturbation vectors, which were obtained by lagged average forecasting simulations. Sensitivity experiments with different numbers of ensemble members, different simulation lengths, and different perturbation magnitudes were performed. Experimental application to a global warming study was also implemented for a typhoon event. Ensemble‐mean results and ensemble spreads of total precipitation, atmospheric conditions showed similar characteristics across the sensitivity experiments. The frequencies of the maximum total and hourly precipitation also showed similar distributions. These results indicate the robustness of the proposed technique. On the other hand, considerable ensemble spread was found in each ensemble experiment. In addition, the results of the application to a global warming study showed possible variations in the future. These results indicate that the proposed technique is useful for investigating various meteorological phenomena and the impacts of global warming. The results of the ensemble simulations also enable the stochastic evaluation of differences in high‐impact weather events. In addition, the impacts of a spectral nudging technique were also examined. The tracks of a typhoon were quite different between cases with and without spectral nudging; however, the ranges of the tracks among ensemble members were comparable. It indicates that spectral nudging does not necessarily suppress ensemble spread.
Observed Responses of Mesospheric Water Vapor to Solar Cycle and Dynamical Forcings
Authors: Remsberg Ellis , Damadeo Robert , Natarajan Murali , Bhatt Praful
Published: March 2018

This study focuses on responses of mesospheric water vapor (H2O) to the solar cycle flux at Lyman‐α wavelength and to dynamical forcings according to the multivariate El‐Nino/Southern Oscillation (ENSO) index. The zonal‐averaged responses are for latitudes from 60°S to 60°N and pressure‐altitudes from 0.01 to 1.0 hPa, as obtained from multiple linear regression analyses of time series of H2O from the Halogen Occultation Experiment for July 1992 to November 2005. The results compare very well with those from a separate simultaneous temporal and spatial (STS) method that also confirms that there are no significant sampling biases affecting both sets of results. Distributions of the seasonal amplitudes for temperature and H2O are in accord with the seasonal net circulation. In general, the responses of H2O to ENSO are anticorrelated with those of temperature. H2O responses to multivariate ENSO index are negative in the upper mesosphere and largest in the Northern Hemisphere; responses in the lower mesosphere are more symmetric with latitude. H2O responses to the Lyman‐α flux (Lya) vary from strong negative values in the uppermost mesosphere to very weak, positive values in the tropical lowermost mesosphere. However, the effects of those H2O responses to the solar activity extend to the rest of the mesosphere via dynamical processes. Profiles of the responses to ENSO and Lya also agree reasonably with published results for H2O at the low latitudes from the Microwave Limb Sounder.
Lower Ionosphere Effects on Narrowband Very Low Frequency Transmission Propagation: Fast Variabilities and Frequency Dependence
Authors: Koh Kuang Liang , Liu Zhongjian , Füllekrug Martin
Published: March 2018

The man‐made narrowband very low frequency transmission from Rhauderfehn, Germany, is studied using high accuracy, microsecond time resolution measurements in Bath, UK. The high time resolution enables a novel comparison of the measurements with a detailed simulation of the transmitted signal. It is found that the wave propagation frequency response exhibits nonlinear amplitude and phase changes with frequency over the narrow transmission bandwidth during the time of the measurements (13 May 2011 15:00:03–15:00:09 UTC). The high time resolution also enables measurements of fast variabilities in the wave propagation <5 ms. The fast propagation variabilities are likely to originate from integrated ionospheric variability over the propagation path or fast ionospheric processes. The wave propagation frequency response measurement has potential benefits in the study of the lower ionosphere, in particular during highly variable perturbations such as those caused by lightning.
Optimization of Large‐Scale Daily Hydrothermal System Operations With Multiple Objectives
Authors: Wang Jian , Cheng Chuntian , Shen Jianjian , Cao Rui , Yeh William W.‐G.
Published: March 2018

This paper proposes a practical procedure for optimizing the daily operation of a large‐scale hydrothermal system. The overall procedure optimizes a monthly model over a period of 1 year and a daily model over a period of up to 1 month. The outputs from the monthly model are used as inputs and boundary conditions for the daily model. The models iterate and update when new information becomes available. The monthly hydrothermal model uses nonlinear programing (NLP) to minimize fuel costs, while maximizing hydropower production. The daily model consists of a hydro model, a thermal model, and a combined hydrothermal model. The hydro model and thermal model generate the initial feasible solutions for the hydrothermal model. The two competing objectives considered in the daily hydrothermal model are minimizing fuel costs and minimizing thermal emissions. We use the constraint method to develop the trade‐off curve (Pareto front) between these two objectives. We apply the proposed methodology on the Yunnan hydrothermal system in China. The system consists of 163 individual hydropower plants with an installed capacity of 48,477 MW and 11 individual thermal plants with an installed capacity of 12,400 MW. We use historical operational records to verify the correctness of the model and to test the robustness of the methodology. The results demonstrate the practicability and validity of the proposed procedure.
Approximate Solutions for Ideal Dam‐Break Sediment‐Laden Flows on Uniform Slopes
Authors: Ni Yufang , Cao Zhixian , Borthwick Alistair , Liu Qingquan
Published: March 2018

Shallow water hydro‐sediment‐morphodynamic (SHSM) models have been applied increasingly widely in hydraulic engineering and geomorphological studies over the past few decades. Analytical and approximate solutions are usually sought to verify such models and therefore confirm their credibility. Dam‐break flows are often evoked because such flows normally feature shock waves and contact discontinuities that warrant refined numerical schemes to solve. While analytical and approximate solutions to clear‐water dam‐break flows have been available for some time, such solutions are rare for sediment transport in dam‐break flows. Here we aim to derive approximate solutions for ideal dam‐break sediment‐laden flows resulting from the sudden release of a finite volume of frictionless, incompressible water‐sediment mixture on a uniform slope. The approximate solutions are presented for three typical sediment transport scenarios, i.e., pure advection, pure sedimentation, and concurrent entrainment and deposition. Although the cases considered in this paper are not real, the approximate solutions derived facilitate suitable benchmark tests for evaluating SHSM models, especially presently when shock waves can be numerically resolved accurately with a suite of finite volume methods, while the accuracy of the numerical solutions of contact discontinuities in sediment transport remains generally poorer.
The Role of Narratives in Sociohydrological Models of Flood Behaviors
Authors: Leong Ching
Published: March 2018

While current efforts to model sociohydrologic phenomena provide crucial insight, critics argue that these do not fully reflect the complexity one observes empirically in the real world. The policy sciences, with its focus on the interaction between human agency and the institutions that constrain public choice, can complement such efforts by providing a narrative approach. This paper demonstrates this complementarity by investigating the idea of resilience in a community response to floods. Using the quantitative Q methodology, we trace the dynamics of a common sociohydrologic hypothesis—the “memory effect” and how it decreases vulnerability and, more crucially, the instances when such memory effects do not obtain. Our analysis of a floodprone maladaptive community in Assam, India, finds four distinct narrative types: the Hardened Preparer, the Engineer, Discontent, and the Pessimist. This paper put forward an explicitly sociohydrological conception of resilience which takes into account the role of sociological indicators such as narrative types and perceptions. Such contextual understandings and narrative types can form the basis of generic resilience indicators which complement the anticipated outcomes of sociohydrologic models generally.