bluuebunny/crossref_metadata_2025 huggingface dataset:
A disseminação da informação no Twitter: uma análise exploratória do fluxo informacional de retweets
Authors: Santana Júnior Célio Andrade , Albuquerque João Pedro Silva , Queiroz Fabiola Souza , Lima Steffane Ramires
Published: June 2015

Introdução: Apresenta o processo de disseminação da informação no serviço de microblog Twitter a partir dos retweets realizados por usuários, que assim disseminam mensagens criadas por perfis. O objetivo desta pesquisa é observar como se deu a disseminação de uma mensagem postada neste serviço de microblog em relação a aspectos teóricos da chamada Teoria de Redes. Método: Utilizou-se a ferramenta “Where Does My Tweet Goes” para avaliar um tweet do político norte-americano Al Gore postado originalmente no dia cinco de junho de 2013. Os dados utilizados nesta pesquisa foram coletados pela própria ferramenta que busca as informações sobre as postagens diretamente na base de dados do Twitter. A análise dos dados foi feita de forma quantitativa a partir da própria ferramenta que identificou os retweets promovidos pelos seguidores de Al Gore. Resultados: Foi observado que a disseminação da mensagem específica se deu de forma rápida, entretanto efêmera. O alcance da mensagem foi, de fato, potencializado pela rede atingindo mais do que o dobro dos seguidores originais de Al Gore sendo assim possível quantificar a “viralidade” de uma postagem. Conclusão: O resultado desta pesquisa, ressaltada sua característica exploratória, sugere que a disseminação da informação no Twitter segue a tendência das denominadas “novas ciências” em redes sociais caracterizadas pela dinâmica dos elementos redes na sua construção e crescimento.
Avaliação da eficácia da “política mandatória” em repositórios: um estudo de caso no Instituto Politécnico de Castelo Branco – Portugal
Authors: Rodrigues Maria Eduarda Pereira , Rodrigues António Moitinho
Published: June 2015

Introdução: Apresentam-se os resultados de um estudo sobre o efeito da aprovação e implantação da Política de Depósito de Documentos (PDD) no Repositório Científico do Instituto Politécnico de Castelo Branco - Portugal (RCIPCB). Método: O trabalho foi dividido em duas partes. A primeira parte diz respeito à posição dos docentes/investigadores sobre a PDD e sobre o arquivamento dos seus documentos científicos no Repositório; a segunda parte diz respeito ao desempenho do RCIPCB enquanto tal. O estudo foi realizado mediante a aplicação de um inquérito distribuído online aos docentes/investigadores do IPCB (n=505), sujeito a uma análise estatística descritiva. Resultados: 96,6% dos docentes/investigadores informaram conhecer o RCIPCB; 66,0% dos inquiridos respondeu conhecer a PDD; apenas 11,9% dos respondentes indicaram ter depositado de quatro a mais documentos da sua produção científica de 2011 no Repositório; e, 50,8% dos docentes/investigadores referiram não terem depositado qualquer documento relativo a 2011. As razões mais invocadas para este comportamento foram: a falta de tempo (43,5%); questões relacionadas com direitos de autor (21,7%); e o esquecimento (17,4%). Após a aprovação da PDD houve uma redução no número total de documentos depositados (10,3%) e do número de documentos autoarquivados (44,0%). Conclusões: Conclui-se que a PDD não produziu os resultados desejados nem ao nível do autoarquivo, nem ao nível do crescimento do Repositório pela via do arquivo mediado.  Considera-se ser necessária a adoção de medidas complementares de fomento do arquivo e do autoarquivo no RCIPCB.
Modelo conceitual para jogos educativos digitais
Authors: Jappur Rafael Feyh , Forcellini Fernando Antonio , Spanhol Fernando Jose
Published: June 2015

Introdução: Apresenta o desenvolvimento de uma proposta de modelo conceitual para jogos educativos digitais no contexto da sala de aula, tendo como foco de análise a aprendizagem para hábitos sustentáveis de consumo e produção no ambiente residencial. Os modelos conceituais existentes estão mais ligados à criação e recentemente à avaliação dos jogos. Já no contexto da aplicação, a maioria dos modelos foca primordialmente na descrição dos processos de validação dos jogos do que na mediação da prática pedagógica em si. Portanto, a questão de pesquisa versa sobre em como criar, aplicar e avaliar jogos educativos digitais para o processo de ensino e aprendizagem em sala de aula, tendo como foco de aprendizagem a cultura da sustentabilidade no ambiente residencial. Metodologia: Realizou-se pesquisa bibliográfica e de campo como parte prática para a coleta de dados. Ressalta-se o uso do Design Science Research Methodology como procedimento metodológico para o desenvolvimento do modelo conceitual. Resultados: O mesmo foi testado em um estudo piloto em duas turmas do programa jovem aprendiz do SENAC/SC para verificação de sua consistência. Conclusões: Conclui-se com base nos resultados apresentados pela aplicação do piloto que o modelo conceitual proposto contribui para o processo de ensino e aprendizagem em sala de aula.
VARIABILIDADE DAS CHUVAS NA VERTENTE PARANAENSE DA BACIA DO RIO PARANAPANEMA - 1999-2000 A 2009-2010
Authors: Carmello Vinicius , Sant'Anna Neto João Lima
Published: June 2015

Os investimentos no campo vêm sendo ampliados ao longo das últimas décadas, sobretudo pela justificativa de se minimizar as repercussões, ditas “naturais”, no território agrícola ocupado. O objetivo deste artigo é analisar a variabilidade das chuvas na vertente paranaense da bacia do rio Paranapanema em período de safra de soja (outubro – abril). Para tanto, foram aplicadas duas técnicas estatísticas: Mann-Kendall e Percentil, com o intuito de estudar a tendência e a variabilidade dos totais anuais de chuva da série histórica entre os anos 1999-2000 a 2009-2010. Para isso utilizou-se dados de precipitação de 89 postos pluviométricos administrados pelo Instituto das Águas do Paraná. Ademais, definiram-se períodos extremamente secos, secos, habituais, chuvosos e extremamente chuvosos, representados em um painel tempo-espacial. Quanto ao teste de Mann-Kendall: 13 postos pluviométricos apresentaram tendência positiva de aumento das chuvas. No que se refere aos resultados mais expressivos relacionados à variabilidade da chuva anual acumulada, concluiu-se que o ano agrícola de 1999–2000 foi definido como padrão seco, em contraposição ao ano agrícola chuvoso de 2009–2010. Os valores de produtividade de soja utilizados para medir o impacto desses períodos extremos também evidenciam variações em resposta aos registros pluviométricos de cada ano.
ANÁLISE DIRECIONAL DA EXPANSÃO URBANA DE CIDADES DE PORTE MÉDIO: Uma aplicação da dimensão fractal
Authors: Trentin Gracieli , Ferreira Marcos César
Published: June 2015

A irregularidade das áreas urbanas traz a necessidade de novas formas de análise que considerem a morfologia urbana e não somente sua área ocupada. O objetivo deste trabalho foi identificar e caracterizar a forma de cidades de porte médio, utilizando a estimativa da dimensão fractal (D) pela densidade de ocupação a partir da análise setorial das formas urbanas em quatro datas de análise: 1938, 1985, 1995 e 2005. Adicionalmente, foram considerados os aspectos de topografia e as características de uso e ocupação do solo na borda urbana, os quais foram relacionados aos valores calculados de D. Para este estudo foram selecionadas as cidades de São José do Rio Preto e o aglomerado urbano de Jundiaí-Várzea Paulista, ambas no estado de São Paulo. As áreas urbanas foram identificadas por meio de mapas históricos e imagens do satélite LANDSAT TM 5. Círculos concêntricos com intervalos de 500m, posteriormente divididos em setores direcionais de 45o, foram sobrepostos às áreas urbanas, o que possibilitou a obtenção dos valores de D, considerando o afastamento em relação ao centro urbano. As assinaturas fractais mostraram o maior preenchimento urbano na área central de cada cidade e fragmentação em direção às bordas. Os valores de D para os setores direcionais apontaram a maior fragmentação urbana do aglomerado Jundiaí-Várzea Paulista, em vista de sua forma urbana alongada, da influência do sistema viário e da presença de impedâncias espaciais representadas por suas características topográficas e de sítio urbano.
Qué contenidos y qué habilidades cognitivo-lingüísticas emplea el profesorado de primaria y secundaria en la enseñanza de la astronomía
Authors: González Rodríguez Concepción , García Barros Susana , Martinez Losada Cristina
Published: June 2015

Se analizan 373 actividades de enseñanza y 103 cuestiones de evaluación dirigidas al estudio de la astronomía, aportadas por 14 profesores (7 de primaria y 7 de secundaria). Con este análisis se pretende conocer qué aspectos conceptuales y qué habilidades cognitivo-lingüísticas se incluyen en ellas. Los resultados muestran que el profesorado tiende a priorizar el estudio de los aspectos más complejos -la Tierra en el espacio- y en lo referente a las habilidades cognitivo-lingüísticas a solicitar la descripción de modelos teóricos. Además se detectan ciertas diferencias entre los dos colectivos de profesores, el de secundaria asocia más equilibradamente las habilidades a los distintos aspectos astronómicos que el de primaria. Finalmente se presentan recomendaciones didácticas de los resultados.
Espacios de trabajo geométrico sintético y analítico de profesores y su práctica en el aula
Authors: Henríquez Rivas Carolina Andrea , Montoya Delgadillo Elizabeth
Published: June 2015

En este trabajo mostramos los resultados de un estudio realizado sobre el trabajo matemático de dos profesores nóveles en su práctica en el aula, cuando las temáticas involucran los enfoques de geometría euclidiana sintéticos y analíticos. Presentamos el Espacio de Trabajo Matemático (ETM) idóneo de cada docente, específicamente las circulaciones entre las componentes de los planos epistemológico y cognitivo y, el paradigma geométrico privilegiado. Los resultados proporcionan datos empíricos respecto a la práctica docente al usar distintos métodos geométricos y sobre la posibilidad de complementarlos, además, el tema se presenta como una nueva dimensión de estudio para el ETM.
La resolución de problemas y el desarrollo de la flexibilidad del pensamiento matemático en la Educación Secundaria Básica
Authors: Díaz Lozada Jorge Antonio
Published: June 2015

En la tesis se propone una estrategia didáctica para el desarrollo de la flexibilidad del pensamiento matemático a través de la resolución de problemas en la Educación Secundaria Básica.Se estudian los fundamentos teóricos metodológicos de la resolución de problemas y su función desarrolladora; se analizan diferentes enfoques del tema y se reconoce que no ha sido abordado lo suficiente el desarrollo de la flexibilidad del pensamiento matemático en las investigaciones anteriores acerca del mismo.Como resultado de las relaciones esenciales que se revelan en el proceso investigativo se estructura la estrategia didáctica. Esta se validó mediante el criterio de expertos y un cuasiexperimento, para constatar su factibilidad.
Editorial
Authors: Enseñanza de las Ciencias Revista
Published: June 2015

Editorial
Seeing through New Eyes: An Experimental Investigation of the Benefits of Photography
Authors: Jaime L. Kurtz
Published: June 2015

This study examined the affective and cognitive benefits of taking photographs of one’s everyday surroundings. Thirty-eight undergraduate participants were randomly assigned to either take photographs in a mindful, creative way; take photographs in a neutral, factual way; or do a count-your-blessings writing exercise, an activity that is known to reliably increase mood [1]. Planned contrasts revealed that those taking mindful, creative photographs were, on average, in a significantly better mood and were significantly more appreciative and motivated than those taking neutral photographs. There were no significant differences between either photography condition and the writing activity. These results suggest that, when done thoughtfully, photography can be an effective way of improving mood and appreciation of everyday life.
« Le narrateur se lève » : narration indécidable et fondation illégitime dans Les particules élémentaires de Michel Houellebecq
Authors: Thériault Patrick
Published: June 2015

Le lecteur des Particules élémentaires ne peut qu’être déconcerté par l’apparition, vers la fin du roman et dans le cadre même de la représentation, d’un personnage identifié (au) « narrateur » : « Le narrateur se lève ». En faisant « se lever » ce narrateur-personnage, le texte de Michel Houellebecq soulève une question d’ordre référentiel qu’on ne peut, en toute rigueur, ignorer : qui (quelle instance, quelle voix, quelle figure), en venant comme le dédoubler, s’énonce ainsi à la place du narrateur-personnage ? Le roman n’offre aucune réponse certaine à cette question ; il engramme en cela une forme d’énigme narratologique qu’on peut qualifier d’indécidable. Pour autant, cette énigme n’en est pas moins un index critique et un levier heuristique de première importance, à travers lesquels, comme j’en ferai l’hypothèse, il est possible d’entrapercevoir la richesse épistémologique des Particules élémentaires. De manière plus précise, je m’attacherai à montrer comment, en posant la question du métalangage et en confinant en dernière analyse à ce que Jean-François Lyotard appelle l’« aporie logique de l’autorisation », cette énigme narratologique fait dialoguer le roman de Houellebecq avec le discours philosophique sur la postmodernité et la fin de l’Histoire.
Genre, géographie et héritage : lecture éthique du style du narrateur dans L’annonce de Marie-Hélène Lafon
Authors: Langevin Francis
Published: June 2015

Cet article propose une lecture du roman L’annonce (2009) de Marie-Hélène Lafon et illustre un parcours qui va du style vers l’individualité et l’intentionnalité, afin de montrer une partie de l’activité interprétative à laquelle donne lieu une indécidabilité quant à la source (pragmatique) du style de la narration, des évaluations et, partant, des valeurs. Il présente pour ce faire un état des lieux critique entre la construction énonciative des valeurs (Hamon, Korthals Altes, Jouve) et la construction énonciative du point de vue (Rabatel). Il affirme en outre que la lecture ne se satisfait que momentanément de l’indécidabilité quand il est nécessaire d’attribuer des valeurs, et que ce mode de lecture est aussi sensible aux positions énonciatives qu’aux positions éthiques que lui propose le texte. Plus précisément, l’auteur s’intéresse aux effets éthiques du style et observe comment se construisent des ponts entre le style, garantie de littérarité, et l’idéologie, référent extratextuel. Dans le roman L’annonce, ce sont en particulier le genre sexuel, l’origine géographique et l’héritage paysan qui semblent être l’enjeu des évaluations et du style de la narration.
Small steps and giant leaps
Authors: Prevo Bram , Peterman Erwin JG
Published: June 2015

A study of kinesin-1 has shed new light on how motor proteins are able to move along microtubules inside cells.
Modified 1-Layer Duct-to-Mucosa Pancreaticojejunostomy Reduces Pancreatic Fistula After Pancreaticoduodenectomy
Authors: Wei Jishu , Liu Xinchun , Wu Junli , Xu Wenbin , Zhou Jia , Lu Zipeng , Chen Jianmin , Guo Feng , Gao Wentao , Li Qiang , Jiang Kuirong , Dai Cuncai , Miao Yi
Published: June 2015

Postoperative pancreatic fistula (POPF) is a major source of morbidity after pancreaticoduodenectomy (PD). The purpose of this retrospective study comparing 1-layer pancreaticojejunostomy (PJ) with 2-layer PJ after PD was to evaluate whether the 1-layer duct-to-mucosa PJ after PD can reduce the incidence of POPF. A total of 194 consecutive patients who underwent PD by one group of surgeons (led by Y.M.) from January 2011 to February 2014 were included in this study. Among those patients, 104 underwent 1-layer PJ (1-layer group), and 90 patients underwent 2-layer PJ (2-layer group). Preoperative clinicopathologic features, intraoperative parameters, and postoperative morbidity with a focus on POPF were compared between the 2 groups. The overall incidence of POPF was 19.6% (38 of 194 patients), and clinically relevant grade B and C POPF rates were 8.6% (16 of 194 patients) and 3.1% (6 of 194 patients), respectively. There were no differences in patient demographics and operation-related factors between the 2 groups. However, the incidence of POPF in the 1-layer group was significantly lower than in the 2-layer group [13.5% (14 of 104) of patients and 26.7% (24 of 90) of patients, respectively; P = 0.021]. The median postoperative hospital stay was also significantly shorter in the 1-layer group compared with the 2-layer group (13 versus 15 days, P = 0.035). One patient in the 2-layer group died of postoperative hemorrhage. One-layer duct-to-mucosa PJ is a simple and easy technique for pancreaticojejunal anastomosis after PD, and it can reduce the POPF rate in comparison with the 2-layer technique.
How sensitive are aerosol‐precipitation interactions to the warm rain representation?
Authors: Hill A. A. , Shipway B. J. , Boutle I. A.
Published: June 2015

It is widely acknowledged that aerosol‐cloud interactions are a major uncertainty in climate and numerical weather prediction. One of the sources of uncertainty is the sensitivity of the cloud microphysics parameterization to changes in aerosol, in particular the response of precipitation. In this work, we conduct an idealized, dynamically consistent, intercomparison of warm rain microphysics schemes to understand this source of uncertainty. The aims of this investigation are: (i) investigate how sensitive precipitation susceptibility (S0) is to cloud microphysics representation and (ii) use S0 to determine the minimum complexity of microphysics required to produce a consistent precipitation response to changes in cloud drop number concentration (Nd). The main results from this work are: (i) over a large range of liquid water path and Nd, all the bulk schemes, but particularly the single moment schemes, artificially produce rain too rapidly. Relative to a reference bin microphysics scheme, this leads to a low in‐cloud S0 and impacts the evolution of S0 over time. (ii) Rain evaporation causes surface S0 from all schemes to be larger than the cloud base S0. The magnitude of the change in S0 with altitude is dependent on the scheme and the representation of the rain drop size distribution. Overall, we show that single‐moment schemes produce the largest range in the sensitivity of precipitation to changes in Nd. Modifying rain production parameterization alone does not reduce this spread. Instead, increasing the complexity of the rain representation to double‐moment significantly improves this behavior and the overall consistency between schemes.
Biogeochemical drivers of the fate of riverine mercury discharged to the global and Arctic oceans
Authors: Zhang Yanxu , Jacob Daniel J. , Dutkiewicz Stephanie , Amos Helen M. , Long Michael S. , Sunderland Elsie M.
Published: June 2015

Rivers discharge 28 ± 13 Mmol yr−1 of mercury (Hg) to ocean margins, an amount comparable to atmospheric deposition to the global oceans. Most of the Hg discharged by rivers is sequestered by burial of benthic sediment in estuaries or the coastal zone, but some is evaded to the atmosphere and some is exported to the open ocean. We investigate the fate of riverine Hg by developing a new global 3‐D simulation for Hg in the Massachusetts Institute of Technology ocean general circulation model. The model includes plankton dynamics and carbon respiration (DARWIN project model) coupled to inorganic Hg chemistry. Results are consistent with observed spatial patterns and magnitudes of surface ocean Hg concentrations. We use observational constraints on seawater Hg concentrations and evasion to infer that most Hg from rivers is sorbed to refractory organic carbon and preferentially buried. Only 6% of Hg discharged by rivers (1.8 Mmol yr−1) is transported to the open ocean on a global basis. This fraction varies from a low of 2.6% in East Asia due to the barrier imposed by the Korean Peninsula and Japanese archipelago, up to 25% in eastern North America facilitated by the Gulf Stream. In the Arctic Ocean, low tributary particle loads and efficient degradation of particulate organic carbon by deltaic microbial communities favor a more labile riverine Hg pool. Evasion of Hg to the Arctic atmosphere is indirectly enhanced by heat transport during spring freshet that accelerates sea ice melt and ice rafting. Discharges of 0.23 Mmol Hg yr−1 from Arctic rivers can explain the observed summer maximum in the Arctic atmosphere, and this magnitude of releases is consistent with recent observations. Our work indicates that rivers are major contributors to Hg loads in the Arctic Ocean.
Magmatic water contents determined through clinopyroxene: Examples from the Western Canary Islands, Spain
Authors: Weis Franz A. , Skogby Henrik , Troll Valentin R. , Deegan Frances M. , Dahren Börje
Published: June 2015

Water is a key parameter in magma genesis, magma evolution, and resulting eruption styles, because it controls the density, the viscosity, as well as the melting and crystallization behavior of a melt. The parental water content of a magma is usually measured through melt inclusions in minerals such as olivine, a method which may be hampered, however, by the lack of melt inclusions suitable for analysis, or postentrapment changes in their water content. An alternative way to reconstruct the water content of a magma is to use nominally anhydrous minerals (NAMs), such as pyroxene, which take up low concentrations of hydrogen as a function of the magma's water content. During magma degassing and eruption, however, NAMs may dehydrate. We therefore tested a method to reconstruct the water contents of dehydrated clinopyroxene phenocrysts from the Western Canary islands (n = 28) through rehydration experiments followed by infrared and Mössbauer spectroscopy. Employing currently available crystal/melt partitioning data, the results of the experiments were used to calculate parental water contents of 0.71 ± 0.07 to 1.49 ± 0.15 wt % H2O for Western Canary magmas during clinopyroxene crystallization at upper mantle conditions. This H2O range is in agreement with calculated water contents using plagioclase‐liquid‐hygrometry, and with previously published data for mafic lavas from the Canary Islands and comparable ocean island systems elsewhere. Utilizing NAMs in combination with hydrogen treatment can therefore serve as a proxy for pre‐eruptive H2O contents, which we anticipate becoming a useful method applicable to mafic rocks where pyroxene is the main phenocryst phase.
Shorter intervals between great earthquakes near Sendai: Scour ponds and a sand layer attributable to A.D. 1454 overwash
Authors: Sawai Yuki , Namegaya Yuichi , Tamura Toru , Nakashima Rei , Tanigawa Koichiro
Published: June 2015

A sparsely documented tsunami in 1454 may subdivide the recurrence interval between the 869 and 2011 tsunamis near Sendai, as judged from geomorphic, stratigraphic, and archival evidence. Pond‐filled breaches cut across beach ridges on century‐old topographic maps. The basal pond deposit in one of these breaches postdates 1454. Stratigraphy on Sendai Plain includes a sand sheet that contains marine and brackish diatoms. Radiocarbon ages suggest that the sheet dates to 1406–1615 (2σ), and written records for this interval in Tohoku mention a tsunami in 1454. The inferred inundation extended 1.0–2.5 km inland from an approximate medieval shoreline. Simulated tsunamis that best account for the sand sheet require a thrust earthquake of moment magnitude 8.4 or larger. If the sand sheet represents the 1454 tsunami, the two most recent intervals between great thrust earthquakes in Sendai region spanned 585 and 557 years.
Acoustic source inversion to estimate volume flux from volcanic explosions
Authors: Kim Keehoon , Fee David , Yokoo Akihiko , Lees Jonathan M.
Published: June 2015

We present an acoustic waveform inversion technique for infrasound data to estimate volume fluxes from volcanic eruptions. Previous inversion techniques have been limited by the use of a 1‐D Green's function in a free space or half space, which depends only on the source‐receiver distance and neglects volcanic topography. Our method exploits full 3‐D Green's functions computed by a numerical method that takes into account realistic topographic scattering. We apply this method to vulcanian eruptions at Sakurajima Volcano, Japan. Our inversion results produce excellent waveform fits to field observations and demonstrate that full 3‐D Green's functions are necessary for accurate volume flux inversion. Conventional inversions without consideration of topographic propagation effects may lead to large errors in the source parameter estimate. The presented inversion technique will substantially improve the accuracy of eruption source parameter estimation (cf. mass eruption rate) during volcanic eruptions and provide critical constraints for volcanic eruption dynamics and ash dispersal forecasting for aviation safety. Application of this approach to chemical and nuclear explosions will also provide valuable source information (e.g., the amount of energy released) previously unavailable.
Roles of wind shear at different vertical levels: Cloud system organization and properties
Authors: Chen Qian , Fan Jiwen , Hagos Samson , Gustafson William I. , Berg Larry K.
Published: June 2015

Understanding critical processes that contribute to the organization of mesoscale convective systems (MCSs) is important for accurate weather forecasts and climate predictions. In this study, we investigate the effects of wind shear at different vertical levels on the organization and properties of convective systems using the Weather Research and Forecasting model with spectral bin microphysics. Based on a control run for a MCS with weak wind shear (Ctrl), we find that increasing wind shear at the lower troposphere (L‐shear) leads to a more organized quasi‐line convective system. Strong wind shear in the middle troposphere (M‐shear) tends to produce large vorticity and form a mesocyclone circulation and an isolated strong storm that leans toward supercellular structure. By increasing wind shear at the upper vertical levels only (U‐shear), the organization of the convection is not changed much, but the convective intensity is weakened. Increasing wind shear in the middle troposphere for the selected case results in a significant drying, and the drying is more significant when conserving moisture advection at the lateral boundaries, contributing to the suppressed convective strength and precipitation relative to Ctrl. Precipitation in the L‐shear and U‐shear does not change much from Ctrl. Evident changes of cloud macrophysical and microphysical properties in the strong wind shear cases are mainly due to large changes in convective organization and water vapor. The insights obtained from this study help us better understand the major factors contributing to convective organization and precipitation.
The role of blocking in the summer 2014 collapse of Etesians over the eastern Mediterranean
Authors: Tyrlis Evangelos , Tymvios Filippos S. , Giannakopoulos Christos , Lelieveld Jos
Published: June 2015

We investigate the dynamical harbingers leading to the remarkable summer 2014 decline of the northerly flow (Etesians) over the eastern Mediterranean. From mid‐July to mid‐August four distinct episodes of unseasonal southerly flow were identified and associated with upper level troughs over central Europe and the Balkans. These features developed as repeated episodes of wave breaking, leading to blocking over Europe in July, and triggered equatorward streamers of high potential vorticity. During July a twofold increase in blocking occurrence against climatology was identified over parts of Europe and was part of a five‐wave hemispheric pattern featuring abundant high‐latitude blocking also over central Asia, the central Pacific, and western Atlantic. Overall, the frequent European blocking resulted in the southward displacement of the midlatitude storm track toward the Balkans and the relaxation of the traditional sharp east‐west pressure gradient that triggered the collapse of Etesians. The bifurcation of the midlatitude jet caused by blocking led to the intensification of the westerly flow over the Mediterranean, accompanying the passing disturbances farther to the north, which combined with the weak Etesians resulting in a dramatic modification of the large‐scale circulation over the Mediterranean Basin.
Analysis of the radiative budget of the Venusian atmosphere based on infrared Net Exchange Rate formalism
Authors: Lebonnois Sébastien , Eymet Vincent , Lee Christopher , Vatant d'Ollone Jan
Published: June 2015

A detailed one‐dimensional analysis of the energy balance in Venus atmosphere is proposed in this work, based on the Net Exchange Rate formalism that allows the identification in each altitude region of the dominant energy exchanges controlling the temperature. Well‐known parameters that control the temperature profile are the solar flux deposition and the cloud particle distribution. Balance between solar heating and infrared energy exchanges is analyzed for each region: upper atmosphere (from cloud top to 100 km), upper cloud, middle cloud, cloud base, and deep atmosphere (cloud base to surface). The energy accumulated below the clouds is transferred to the cloud base through infrared windows, mostly at 3–4 μm and 5–7 μm. The continuum opacity in these spectral regions is not well known for the hot temperatures and large pressures of Venus's deep atmosphere but strongly affects the temperature profile from cloud base to surface. From cloud base, upward transport of energy goes through convection and short‐range radiative exchanges up to the middle cloud where the atmosphere is thin enough in the 20–30 μm window to cool directly to space. Total opacity in this spectral window between the 15 μm CO2 band and the CO2 collision‐induced absorption has a strong impact on the temperature in the cloud convective layer. Improving our knowledge of the gas opacities in these different windows through new laboratory measurements or ab initio computations, as well as improving the constraints on cloud opacities would help to separate gas and cloud contributions and secure a better understanding of Venus's atmosphere energy balance.
Multi‐PLL with two‐stage fusion to mitigate ionospheric scintillation effects on GPS receivers
Authors: Xu Rui , Liu Zhizhao , Chen Wu
Published: June 2015

Ionospheric scintillation poses a great threat to the reliability and accuracy of Global Positioning System (GPS) in various applications. It can increase tracking errors of the phase‐locked loop (PLL) in a GPS receiver and even cause the PLL loss of lock under severe scintillations. To mitigate the effect of scintillation on GPS receivers, especially to reduce the occurrence of loss of lock, a multi‐PLL with two‐stage fusion (i.e., tracking fusion and output fusion) is proposed in this paper. This algorithm integrates several parallel sub‐PLLs with different loop parameters into one channel to track one GPS satellite's signal. Every sub‐PLL has its own discriminator, loop filter, carrier numerical controlled oscillator, and a tracking fusion (i.e., the first stage fusion). The tracking fusion of each sub‐PLL integrates the Doppler frequency measurements from all other sub‐PLLs to detect the state of its own sub‐PLL and feeds back reliable Doppler frequency measurements. Simultaneously, the tracking fusion outputs the Doppler frequency measurements to the second stage fusion (i.e., output fusion), which integrates the outputs from all tracking fusions to provide continuous and accurate Doppler frequency measurements for the following positioning/navigation estimator. Performances of the proposed algorithm are tested using real‐world GPS data with different levels of scintillations and compared with results from single‐PLLs. For three real‐world scintillation cases (S4 = 0.26–1.1, σϕ = 0.05–1.49 rad, and average C/N0 = 41.2–45.7 dB Hz), the multi‐PLL algorithm performs more robustly than the single‐PLLs and is able to keep tracking in all scintillation cases.
Internal Magnetic Structure of Nanoparticles Dominates Time‐Dependent Relaxation Processes in a Magnetic Field
Authors: Dennis Cindi L. , Krycka Kathryn L. , Borchers Julie A. , Desautels Ryan D. , van Lierop Johan , Huls Natalie F. , Jackson Andrew J. , Gruettner Cordula , Ivkov Robert
Published: June 2015

Magnetic nanoparticles provide a unique combination of small size and responsiveness to magnetic fields making them attractive for applications in electronics, biology, and medicine. When exposed to alternating magnetic fields, magnetic nanoparticles can generate heat through loss power mechanisms that continue to challenge a complete physical description. The influence of internal nanoparticle (intracore) magnetic domain structure on relaxation remains unexplored. Within the context of potential biomedical applications, this study focuses on the dramatic differences observed among the specific loss power of three magnetic iron oxide nanoparticle constructs having comparable size and chemical composition. Analysis of polarization analyzed small angle neutron scattering data reveals unexpected and complex coupling among magnetic domains within the nanoparticle cores that influences their interactions with external magnetic fields. These results challenge the prevailing concepts in hyperthermia which limit consideration to size and shape of magnetic single domain nanoparticles.
Graphene‐Based Materials in Regenerative Medicine
Authors: Ding Xili , Liu Haifeng , Fan Yubo
Published: June 2015

Graphene possesses many unique properties such as two‐dimensional planar structure, super conductivity, chemical and mechanical stability, large surface area, and good biocompatibility. In the past few years, graphene‐based materials have risen as a shining star on the path of researchers seeking new materials for future regenerative medicine. Herein, the recent research advances made in graphene‐based materials mostly utilizing the mechanical and electrical properties of graphene are described. The most exciting findings addressing the impact of graphene‐based materials on regenerative medicine are highlighted, with particular emphasis on their applications including nerve, bone, cartilage, skeletal muscle, cardiac, skin, adipose tissue regeneration, and their effects on the induced pluripotent stem cells. Future perspectives and emerging challenges are also addressed in this Review article.
Organocatalytic Enantioselective Michael Reaction of Malononitrile with β,β‐Disubstituted Nitroalkenes
Authors: Chen Shengwei , Lou Qinxin , Ding Yuyang , Zhang Shasha , Hu Wenhui , Zhao Junling
Published: June 2015

We have developed and optimized an enantioselective Michael reaction of malononitrile with β,β‐disubstituted nitroalkenes. This reaction was catalyzed by a cinchona alkaloid derived thiourea catalyst, producing products of high yields (up to 98 %) and stereoselectivities (up to 93 % ee). One of the adducts was used as an intermediate for the synthesis of dihydropyrrole derivative bearing a synthetically valuable quaternary chiral center.

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Azimuthally oscillating membrane emulsification for controlled droplet production
Authors: Silva Pedro S. , Dragosavac Marijana M. , Vladisavljević Goran T. , Bandulasena Hemaka C. H. , Holdich Richard G. , Stillwell Mike , Williams Bruce
Published: June 2015

A novel membrane emulsification (ME) system is reported consisting of a tubular metal membrane, periodically azimuthally (tangentially) oscillated with frequencies up to 50 Hz and 7 mm displacement in a gently cross flowing continuous phase. A computational fluid dynamics (CFD) analysis showed consistent axial shear at the membrane surface, which became negligible at distances from the membrane surface greater than 0.5 mm. For comparison, CFD analysis of a fully rotating ME system showed local vortices in the continuous phase leading to a variable shear along the axis of the membrane. Using an azimuthally oscillating membrane, oil‐in‐water emulsions were experimentally produced with a median diameter of 20–120 μm, and a coefficient of variation of droplet size of 8%. The drop size was correlated with shear stress at the membrane surface using a force balance. In a single pass of continuous phase, it was possible to achieve high dispersed phase concentrations of 40% v/v. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3607–3615, 2015
Nucleation curves of model natural gas hydrates on a quasi‐free water droplet
Authors: Maeda Nobuo
Published: June 2015

Heterogeneous nucleation probability distributions of gas hydrates on a water droplet that was supported by inert and immiscible perfluorocarbon oil, perfluorodecalin is studied. The guest gas used was a mixture of 90 mol % methane and 10 mol % propane. The probability distribution was measured using a high pressure automated lag time apparatus under the guest gas pressure range of 6.7–12.5 MPa and the cooling rate range of 0.002–0.02 K/s. Nucleation curves were derived for unit area of water surface. The nucleation rate per unit area of water surface that was contained in a glass sample cell, which differed significantly from that on a quasi‐free water droplet, is also derived. It is concluded that the nucleation curves in the presence of a solid wall should be normalized to the unit length of the three‐phase line at which water, guest gas, and the solid wall meet. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2611–2617, 2015
Isotope‐Filtered 4D NMR Spectroscopy for Structure Determination of Humic Substances
Authors: Bell Nicholle G. A. , Michalchuk Adam A. L. , Blackburn John W. T. , Graham Margaret C. , Uhrín Dušan
Published: June 2015

Humic substances, the main component of soil organic matter, could form an integral part of green and sustainable solutions to the soil fertility problem. However, their global‐scale application is hindered from both scientific and regulatory perspectives by the lack of understanding of the molecular make‐up of these chromatographically inseparable mixtures containing thousands of molecules. Here we show how multidimensional NMR spectroscopy of isotopically tagged molecules enables structure characterization of humic compounds. We illustrate this approach by identifying major substitution patterns of phenolic aromatic moieties of a peat soil fulvic acid, an operational fraction of humic substances. Our methodology represents a paradigm shift in the use of NMR active tags in structure determination of small molecules in complex mixtures. Unlike previous tagging methodologies that focused on the signals of the tags, we utilize tags to directly probe the identity of the molecules they are attached to.
Solution‐Phase Conversion of Bulk Metal Oxides to Metal Chalcogenides Using a Simple Thiol–Amine Solvent Mixture
Authors: McCarthy Carrie L. , Webber David H. , Schueller Emily C. , Brutchey Richard L.
Published: June 2015

A thiol–amine solvent mixture is used to dissolve ten inexpensive bulk oxides (Cu2O, ZnO, GeO2, As2O3, Ag2O, CdO, SnO, Sb2O3, PbO, and Bi2O3) under ambient conditions. Dissolved oxides can be converted to the corresponding sulfides using the thiol as the sulfur source, while selenides and tellurides can be accessed upon mixing with a stoichiometric amount of dissolved selenium or tellurium. The practicality of this method is illustrated by solution depositing Sb2Se3 thin films from compound inks of dissolved Sb2O3 and selenium that give high photoelectrochemical current response. The direct band gap of the resulting material can be tuned from 1.2–1.6 eV by modulating the ink formulation to give compositionally controlled Sb2Se3−xSx alloys.
The structure–activity relationship of some hexacoordinated dimethyltin(IV) complexes of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones
Authors: Sharma Arti , Jain Asha , Saxena Sanjiv
Published: June 2015

The study was focused on the structure–activity relationship of some newly synthesized hexacoordinated dimethyltin(IV) complexes of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones. These complexes were screened for their antibacterial activity against a Gram‐negative bacterium (Pseudomonas aeruginosa) and Gram‐positive bacteria (Streptomyces griseus, Staphylococcus aureus, Bacillus subtilis) and the results were compared with those of a standard antibacterial drug. Some of the complexes were also screened for their antifungal activity against various fungi (Aspergillus niger, A. flavus, Trichoderma viride, Fusarium oxysporum) and were found to be active. These new hexacoordinated complexes of dimethyltin(IV) were generated by reactions of dimethyltin(IV) dichloride and sodium salts of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones in 1:1:1 molar ratio in refluxing dry benzene. Plausible structures of these complexes were suggested with the aid of physicochemical and spectroscopic studies. 119Sn NMR spectral data revealed the presence of a hexacoordinated tin centre in these dimethyltin(IV) complexes. Copyright © 2015 John Wiley & Sons, Ltd.
Media studies research in the data‐driven age: How research questions evolve
Authors: Bron Marc , Van Gorp Jasmijn , de Rijke Maarten
Published: June 2015

The introduction of new technologies and access to new information channels continue to change the way media studies researchers work and the questions they seek to answer. We investigate the current practices of media studies researchers and how these practices affect their research questions. Through the analysis of 27 interviews about the research practices of media studies researchers during a research project we developed a model of the activities in their research cycle. We find that information gathering and analysis activities are dominating the research cycle. These activities influence the research outcomes as they determine how research questions asked by media studies researchers evolve. Specifically, we show how research questions are related to the availability and accessibility of data as well as new information sources for contextualization of the research topic. Our contribution is a comprehensive account of the overall research cycle of media studies researchers as well as specific aspects of the research cycle, i.e., information sources, information seeking challenges, and the development of research questions. This work confirms findings of previous work in this area using a previously unstudied group of researchers, as well as providing new details about how research questions evolve.
The sharing economy: Why people participate in collaborative consumption
Authors: Hamari Juho , Sjöklint Mimmi , Ukkonen Antti
Published: June 2015

Information and communications technologies (ICTs) have enabled the rise of so‐called “Collaborative Consumption” (CC):the peer‐to‐peer‐based activity of obtaining, giving, or sharing the access to goods and services, coordinated through community‐based online services.CChas been expected to alleviate societal problems such as hyper‐consumption, pollution, and poverty by lowering the cost of economic coordination within communities. However, beyond anecdotal evidence, there is a dearth of understanding why people participate inCC. Therefore, in this article we investigate people's motivations to participate inCC. The study employs survey data (N = 168) gathered from people registered onto aCCsite. The results show that participation inCCis motivated by many factors such as its sustainability, enjoyment of the activity as well as economic gains. An interesting detail in the result is that sustainability is not directly associated with participation unless it is at the same time also associated with positive attitudes towardsCC. This suggests that sustainability might only be an important factor for those people for whom ecological consumption is important. Furthermore, the results suggest that inCCan attitude‐behavior gap might exist; people perceive the activity positively and say good things about it, but this good attitude does not necessary translate into action.
Systematic assessment of triticale‐based biorefinery strategies: a biomass procurement strategy for economic success
Authors: Melendez Jose , Stuart Paul R
Published: June 2015

An economical supply of biomass feedstock is an essential part of any biorefinery project. With procurement costs accounting for nearly 50% of operating costs, current biomass supply chain and procurement operations must be continuously improved to reduce procurement costs. Strategic negotiations between the farmer (the producer) and the end user (the biorefinery), in which both parties benefit, should also take place. This study examines procurement supply chains for triticale, for a biorefinery, and proposes a financial model that will satisfy both producer and end user. A biomass cost model was developed to determine the procurement costs of triticale biomass. Several biomass procurement supply chain alternatives were evaluated. Results from the study determined that a biorefinery would pay $225 per tonne of biomass for the delivery of 250 002 tonnes of triticale grain and 265 791 tonnes of triticale straw per year. In addition, the study shows that increased yields of triticale and its similarities in growing and harvesting methods with currently produced agricultural crops will rapidly enable it to become a viable feedstock source for biorefineries. The biomass procurement strategy described appears to be an attractive alternative for producers and provides a good basis for furnishing a long‐term cost‐competitive supply of feedstock to the triticale biorefinery. This financial model is based on the premise that the risk and cost of developing increasingly engineered triticale crops will be borne by the biorefinery owner. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd
Prenatal diagnosis of the VACTERL association using routine ultrasound examination
Authors: Debost‐Legrand Anne , Goumy Carole , Laurichesse‐Delmas Hélène , Déchelotte Pierre , Perthus Isabelle , Francannet Christine , Lémery Didier , Gallot Denis
Published: June 2015

Background

The prognosis and early neonatal management of the VACTERL association depend mainly on the severity of malformations ascertained prenatally.

Methods

Here we reviewed the spectrum of clinical features observed in cases of VACTERL association ascertained prenatally through ultrasound examination but examined at birth and compared them with cases ascertained postnatally.

Results

From 1995 to 2011, a total of 19 cases of VACTERL association were observed in our center; 10 were ascertained prenatally and confirmed after birth whereas 9 were ascertained only after birth. The types and frequencies of malformations observed prenatally were as follows: renal malformations (45%), tracheoesophageal fistula (44%), cardiac malformations (20%), vertebral (13%), and limb (11%) defects. Anal atresia was never detected using routine prenatal ultrasound examination.

Conclusion

Further studies of fetuses with the VACTERL association are necessary to better delineate the malformations spectrum observed prenatally to improve the early recognition of the VACTERL association. Birth Defects Research (Part A) 103:880–886, 2015. © 2015 Wiley Periodicals, Inc.
Lego‐bike: A challenging robotic lab project to illustrate rapid prototyping in the mindstorms/simulink integrated platform
Authors: Basso Michele , Innocenti Giacomo
Published: June 2015

LEGO© Mindstorms is a widely spread affordable education robotic platform, that has recently gained native support from the Mathworks© simulation environment Simulink. The pros and cons of the integrated Mindstorms/Simulink framework are actually illustrated through a complex model based control design project featuring a self‐stabilized bicycle, that represents a proper example of the rapid prototyping capability of the platform. The importance of such an integration is discussed taking into account the history and the results of the LEGO‐based learning activities held at the Control Systems Laboratory of the University of Florence for graduate and undergraduate courses. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:947–958, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21666