bluuebunny/crossref_metadata_2025 huggingface dataset:
PORTUGUÊS PARA ESTRANGEIROS A DISTÂNCIA: UMA EXPERIÊNCIA DO CELIN/UFPR
Authors: SALTINI Lygia Maria Leite , MONTEIRO Sandra Lopes , LISBOA Maria Fernanda Araújo , COSTA Roberta Sotero
Published: September 2014

O curso de português para estrangeiros a distância do Celin/UFPR é uma proposta direcionada ao desenvolvimento e ampliação do conhecimento lingüístico-discursivo baseado na concepção bakhtiniana de língua como prática social. Seu principal objetivo é oportunizar ao estudante estrangeiro o acesso à produção de textos de diferentes gêneros para o qual devem ser abordados tópicos gramaticais, socioculturais e pragmáticos. A temática e as tarefas propostas no decorrer das unidades do curso consideram o aprendente como um ator social e procuram fornecer subsídios lingüísticos e culturais visando a competência comunicativa. Ao longo do curso, os alunos serão levados à reflexão sobre a sua língua nativa e sua(s) cultura(s) para que conheçam a cultura brasileira e percebam, com um novo olhar, a sua própria cultura. Durante o curso são propostos diversos gêneros textuais e a cada unidade o grau de complexidade gramatical e de textos orais e escritos aumenta gradativamente, partindo das necessidades básicas de comunicação e de interação social para, depois, falar de seu entorno, seu país e a cultura do outro.
O PROJETO “4 in 1” E O CELIN- UMA PROPOSTA SOCIOINTERACIONAL E MULTIMODAL
Authors: NODARI Janice Inês , De SANTANA Hélio Ribeiro , FERREIRA Márcia , LEYSER Michelle Patrícia
Published: September 2014

O projeto “4 in 1”, implementado no Celin – Centro de Línguas e Interculturalidade da UFPR – Universidade Federal do Paraná, do segundo semestre de 2009 ao primeiro semestre de 2011, objetivava criar um ambiente em que o aluno do Celin pudesse experimentar e vivenciar a língua alvo fora da sala de aula. O projeto recebeu o nome “Four in One” por se propor a trabalhar com esquetes, textos literários, música e filmes, ou seja, quatro ferramentas distintas, cujo elo era a língua inglesa, em uma atmosfera mais descontraída. Os alunos participantes eram dos níveis iniciante ao intermediário, e participavam sob a supervisão de três professores do Celin responsáveis pela proposta. O projeto “4 in 1” se propôs a ir além do material didático, apresentando situações e contextos variados cujo enfoque extrapolava os aspectos estruturais e de fluência da língua inglesa. A proposta encontrou suporte na perspectiva sociointeracional de aprendizagem de língua estrangeira, e buscou insumo teórico em autores como CHIMENTÃO (2006) e HALL (2001), e na visão multimodal de comunicação defendida por KRESS (2010).
HERMES E BONECAS RUSSAS: PARA COMPREENDER A FORMAÇÃO DOCENTE
Authors: MULIK KATIA BRUGINSKI
Published: September 2014

Em sua tese de doutoramento defendida no ano de 2006, Ana Larissa A. M. Oliveira, professora da Faculdade de Letras da Universidade Federal de Minas Gerais, propõe a discussão sobre a ação-colaborativa entre professores de língua inglesa em uma pesquisa-ação de caráter etnográfico. Pelo viés da linguagem, seu objetivo foi analisar os processos de construção e reconstrução do saber docente em uma situação de formação continuada com três professoras de escola pública.
REFLEXÕES SOBRE OS MULTILETRAMENTOS E AS TICS: CONTRIBUIÇÕES PARA A EDUCAÇÃO A DISTÂNCIA
Authors: Da Silva Edna Marta Oliveira , De Mattos Brahim Adriana Cristina Sambugaro
Published: September 2014

Resumo: O objetivo deste trabalho é apresentar algumas reflexões sobre as contribuições do conceito de multiletramentos e do uso das tecnologias de informação e comunicação (TICs) na modalidade de Educação a Distância (EAD). Para a apresentação dessas reflexões pretende-se considerar os pressupostos teóricos advindos das teorias de letramento, mais especificamente dos multiletramentos. A associação de imagens, áudio e vídeo, com ou sem textos escritos, especialmente com as TICs, passam a exigir novas formas de letramento dos  seus usuários, uma vez que a construção de significados  ocorre por meio de modos variados (multimodais). Em outras palavras, as TICs conduzem as reflexões sobre letramento, ampliando o conceito para os multiletramentos, considerados fundamentais para os processos de ensino e de aprendizagem na contemporaneidade em todos os níveis, justamente por considerar o impacto advindo da utilização dos recursos tecnológicos que têm desencadeado novos olhares para o espaço da educação a distância. PALAVRAS-CHAVE: educação a distância; multiletramentos; TICs; linguagem; comunicação. Abstract: This paper aims to present some reflections on the contributions of the multiliteracy concept and the use of information and communication technologies ( ICTs) in the distance education modality. For the presentation of these reflections, it is intended to consider the theoretical assumptions originated from literacy theories, more specifically from multiliteracies. The association of images, audio and video, with or without  written texts , especially with the ICTs,  new ways of literacy of  their  users are required, once the construction of meanings begins to happen by means of varied modes (multimodalities). In other words, the ICTs lead to reflections on literacy, expanding the concept to the multiliteracies regarded as fundamental to the teaching and learning processes in the contemporary world at all levels, precisely by considering the impact resulting from the use of technological resources that has triggered new visions for the distance education area. KEY WORDS: distance learning; multiliteracies; ICTs; language;communication.
TECNOLOGIAS DIGITAIS, LETRAMENTOS E A COLABORAÇÃO NA FORMAÇÃO DE PROFESSORES
Authors: Landim Denise Silva Paes , Ono Fabrício Tetsuya Parreira
Published: September 2014

RESUMO: O artigo buscar compartilhar reflexões acerca da formação de professores em tempos de práticas sociais mediadas pelas tecnologias digitais, que possibilitam não apenas novas formas de ensino e aprendizagem, trabalho, comunicação e relacionamento, mas também apontam para uma condição pós-humana do ser (SANTAELLA 2007). Tais reflexões são fruto de pesquisa realizada com estudantes em uma disciplina de pós-graduação em que se puderam experimentar questões da condição pós-humana em práticas de letramentos (LANKSHEAR e KNOBEL 2011) reveladoras de aprendizagens colaborativas, ubíquas, não-lineares e incertas e que expuseram a questão da diferença na relação com o Outro. PALAVRAS-CHAVE: letramentos; tecnologias digitais; formação de professores; aprendizagem colaborativa. ABSTRACT: This article aims at sharing thoughts on teacher education in times of social practices mediated by digital technologies, which can afford not only new ways of teaching and learning, work, communication and relationships, but also point to a post-human condition of being (SANTAELLA 2007). Such thoughts arise from research carried on with graduate students in which issues of the post-human condition in literacies practices (LANKSHEAR; KNOBEL 2011) revealed learnings that were collaborative, ubiquitous, non-linear and uncertain and that showed the topic of difference in the relation with the Other. KEY WORDS: literacies; digital technologies; teacher education; collaborative learning.
UM ENSAIO SOBRE A PROFISSIONALIZAÇÃO DOCENTE
Authors: Cabral Karina Melissa
Published: September 2014

A profissionalização da atividade docente é o foco de análise e discussão deste texto, a finalidade é tentar assinalar as tendências e as contradições relativas às dimensões pedagógicas e político-educacionais da profissão, levando em consideração os novos desafios da profissão.
ESCRITA E ORALIDADE  DUAS PROGRESSÕES PARALELAS PARA UM DESENVOLVIMENTO COMUM
Authors: Cherem Lúcia Peixoto
Published: September 2014

O ensino da leitura pode ter o mesmo peso que o ensino da opralidade no ensino de uma língua estrangeira. O artigo aborda a necessidade de uma progressão também para o estudo dos textos.
LEITURA EM LÍNGUA ESTRANGEIRA: AS DIFICULDADES DO LEITOR SOB O PONTO DE VISTA DA TEORIA DA EFICIÊNCIA VERBAL
Authors: Procailo Leonilda
Published: September 2014

O presente artigo tem como tópico a capacidade de leitura de textos de divulgação científica em língua estrangeira, por parte de leitores universitários, de nível de graduação e pós-graduação. A hipótese do estudo, baseada na teoria da eficiência verbal de Perfetti (1985, 1988, 2001) é que o vocabulário da língua alvo poderia ser um dos principais obstáculos na leitura. O estudo foi realizado com dez alunos-participantes de nível intermediário de língua inglesa em um instituto de línguas. O instrumento utilizado foi o protocolo verbal em que os participantes eram solicitados a relatar oralmente o que haviam entendido após cada parágrafo lido em silêncio. À medida que liam, deveriam sublinhar as palavras ou expressões que não conheciam ou cuja tradução não sabiam. Os resultados sugerem que grande parte da dificuldade de processamento da informação é gerada pelo desconhecimento do léxico, que, juntamente com outros fatores como o não conhecimento do tópico, da organização formal de um determinado gênero de texto e do esquema geral de pesquisa contribuem para uma leitura menos profunda. A dificuldade com o léxico pode ser visto como um elemento detonador da dificuldade em se acionar esquemas, pois demanda muito dos recursos do sistema da memória.
Take the lead: analise de uma proposta de empoderamento via atividade extra-curricular
Authors: Gamero Raquel
Published: September 2014

O principal objetivo deste trabalho é fazer uma análise do filme Take the leadsob uma perspectiva sócio-histórica de aprendizagem, além de valorizar o uso de ferramentas extra-curriculares para oferecer aos alunos conhecimentos valiosos em sua prática social diária. Nele são discutidos alguns conceitos de constituição do sujeito e como a perspectiva sócio- histórica o compreende (FREITAS, 2002), além de levantar o termo apprenticeship (LAVE, 1996), e sua importância para que se possa compreender  a aquisição de valores éticos e morais relevantes a comunidade de prática ao qual o sujeito está inserido.
O gênero identitário no ambiente escolar: preconceitos e estereótipos
Authors: Battistela Ivone Maria
Published: September 2014

Este trabalho tem por objetivo apresentar um estudo sobre a visão de gênero no ambiente escolar. Propõe mostrar como crianças e jovens veem a mulher e o homem por meio de atribuições  adjetivas e como no espaço escolar reitera-se certos estereótipos em relação ao gênero  feminino e masculino. O trabalho baseou-se na pesquisa qualitativa, na abordagem pós-estruturalista. Concluiu-se que o preconceito de  gênero está ainda muito presente na linguagem verbal e nas atitudes das pessoas.
LETRAMENTO CRÍTICO E INTERCULTURALIDADE NAS AULAS DE LÍNGUA INGLESA NA EDUCAÇÃO DE JOVENS E ADULTOS
Authors: Mulik Katia Bruginski
Published: September 2014

O objetivo deste texto é relatar uma proposta de trabalho realizada com os alunos do ensino médio da Educação de Jovens e Adultos acerca da temática alimentação. As atividades desenvolvidas deram ênfase ao letramento crítico e a interculturalidade. O trabalho foi de suma importância para o desenvolvimento da criticidade e para a reflexão sobre as relações entre cultura e alimentação.
Supervisão pedagógica em uma escola de idiomas: espaços de reflexão?
Authors: Fogaça Francisco Carlos , Gimenez Telma Nunes
Published: September 2014

Esta pesquisa teve por objetivo investigar possibilidades e limites da abordagem reflexiva de supervisão e de formação continuada em uma rede de franquias de ensino de inglês. A fundamentação teórica está centrada no estudo de modelos de formação de professores e de supervisão pedagógica e na abordagem reflexiva de formação docente. A pesquisa envolveu dois coordenadores pedagógicos e duas professoras, sendo analisadas oito sessões de feedback durante quatro meses. O modelo de supervisão predominante nas sessões teve características diretivas, com pouco espaço para reflexão. O estudo aponta para a necessidade de se considerar fatores institucionais na adoção da abordagem reflexiva de formação e de supervisão, para que esta não perca sua natureza transformadora.
AS DIMENSÕES DE VARIAÇÃO DAS LÍNGUAS NAS AULAS DE LÍNGUA ITALIANA EM CONTEXTO UNIVERSITÁRIO: DA GRAMÁTICA À PRAGMÁTICA
Authors: Maia Rocha Bruna , Santos Aflalo Bernardo
Published: September 2014

Este trabalho tem como objetivo verificar se, além da sintaxe, da semântica e de outros pontos gramaticais, os estudantes de duas disciplinas de língua italiana da Universidade de São Paulo refletem também sobre a produção de mensagens adequadas aos vários contextos aos quais são expostos em língua italiana. A partir de um esquema proposto por Berruto (1993) para o grau de formalidade/informalidade de uma série de expressões que designam o verbo “morire” (morrer em italiano), foi feito um estudo para verificar se além de conhecerem o significado das expressões os alunos conheciam também os contextos em que tais expressões deveriam ser usadas. A partir dos resultados, foram conduzidas análises estatísticas com a utilização do software R para a validação dos dados. Comparando diretamente as médias obtidas entre as duas turmas, foi notado um aumento substancial na quantidade de expressões em conformidade com a referência de Berruto da turma que havia estudado a língua italiana por 1 ano para a turma que a havia estudado por 3 anos. Tal aumento evidencia, para a amostra considerada, a melhora da competência pragmática dos estudantes com o aumento de anos de estudo da língua.
REPRESENTAÇÕES VISUAIS DE GRUPOS INDÍGENAS NO JORNAL FOLHA DE SÃO PAULO
Authors: Mizan Souzana
Published: September 2014

Este artigo estuda representações visuais de culturas e grupos sociais considerados subalternos feitas por instituições dominantes e sugere que analisar a maneira pela qual imagens fazem referência ao mundo que vivemos permite-nos compreender a ideologia subjacente a cada representação. A investigação é realizada à luz da abordagem pós-colonial e pós-formalista que parte do princípio que a linguagem (integrando imagem) e a construção do conhecimento do mundo são geradas tanto dentro de um contexto sócio-histórico-ideológico específico quanto dentro de relações socioeconômicas específicas entre os poderosos e os subalternos. O objetivo é propor que atividades de Letramento Crítico Visual (Rose, 2007) levem os alunos a desenvolver ferramentas/recursos para a expansão interpretativa e a análise crítica de imagens dentro da sala de aula, de forma a proporcionar-lhes oportunidades para produzir conhecimento que reconheça as nossas sociedades como multiculturais e resgate os pontos de vista dos subjugados.
A Extração do Ouro na Amazônia e Implicações para o meio ambiente
Authors: Caheté Frederico Silva
Published: September 2014

Para uma melhor compreensão do cenário deste setor produtivo caberia expor um resumo dos fatores que, de uma ou de outra forma, condicionam as suas atividades. Esta compreensão é, ao mesmo tempo, a da lógica das ações dos agentes diversos envolvidos na mineração. Um destes fatores seria de ordem ambiental, ou, especificamente, geoclimático. Nesta dimensão as florestas apresentam-se como um dos grandes limitantes ao acesso às jazidas. Outro fenômeno interferente é o regime das chuvas pois impõe um período de suspensão das atividades. Influenciada por este regime mas que, por sua vez, também impõe limites às atividades encontra-se a configuração da rede hidrográfica. Além da referida importância da distribuição dos cursos d’água, o seu volume também determina uma maior ou menor intimidade com os “veios” de ouro. Outros fatores condicionantes seriam de ordem econômico-financeira. No final da década de 70 e na década de 80 assistiu-se na Amazônia a uma nova corrida do ouro. Embora possa ser considerado um fenômeno multi-condicionado, seja por fatores regionais, nacionais e internacionais, ou, se preferir, conjunturais, há um fator considerado preponderante por diversos autores: a alta do preço do ouro no referido período no mercado internacional (Macmillan, 1993; Cleary, 1990).
Concise Review: The Coming of Age of Stem Cell Treatment for Corneal Surface Damage
Authors: Ramachandran Charanya , Basu Sayan , Sangwan Virender S. , Balasubramanian Dorairajan
Published: September 2014

The cornea is a vital component of the eye because it provides approximately 70% of the refraction and focusing of incoming light. Being the outermost surface of the eye, it faces continuous stress from dryness, photodamage, infection, and injury; however, like the skin, the cornea regularly refreshes itself by shedding its epithelial cells, which are readily replaced, keeping the ocular surface stable and functional. This regular turnover of the corneal epithelial cells occurs through the stem cells in the limbus, an annular ring of a tissue surrounding the cornea, separating it from the sclera and the conjunctival membrane. The loss of this reserve of stem cells leads to a condition called limbal stem cell deficiency. Treatment for this disorder has evolved from transplanting whole limbal tissues to the affected eye to transplanting laboratory cultured limbal cells. This procedure is called cultivated limbal epithelial transplantation (CLET). Since its start in 1997, more than 1,000 CLET procedures have been reported from around the world, with varying degrees of success. In this paper, we compare the methods of cultivation and the outcomes and discuss some problem areas, use of other cells as substitutes for limbal epithelium, and various carrier materials used in transplantation. Our analysis suggests that CLET as a treatment for corneal surface damage has come of age. We also highlight a simpler procedure (simple limbal epithelial transplantation) that involves cultivation of limbal tissue in situ on the surface of the cornea in vivo and that has outcomes comparable to CLET.
Immunoevasive Pericytes From Human Pluripotent Stem Cells Preferentially Modulate Induction of Allogeneic Regulatory T Cells
Authors: Domev Hagit , Milkov Irina , Itskovitz-Eldor Joseph , Dar Ayelet
Published: September 2014

Isolated microvessel-residing pericytes and pericytes from human pluripotent stem cells (hPSCs) exhibit mesenchymal stem cell-like characteristics and therapeutic properties. Despite growing interest in pericyte-based stem cell therapy, their immunogenicity and immunomodulatory effects on nonactivated T cells are still poorly defined, in particular those of vasculogenic hPSC pericytes. We found that tissue-embedded and unstimulated cultured hPSC- or tissue-derived pericytes constitutively expressed major histocompatibility complex (MHC) class I and the inhibitory programmed cell death-ligand 1/2 (PD-L1/2) molecules but not MHC class II or CD80/CD86 costimulatory molecules. Pretreatment with inflammatory mediators failed to induce an antigen-presenting cell-like phenotype in stimulated pericytes. CD146+ pericytes from hPSCs did not induce activation and proliferation of allogeneic resting T cells independent of interferon (IFN)-γ prestimulation, similarly to pericytes from human brain or placenta. Instead, pericytes mediated a significant increase in the frequency of allogeneic CD25highFoxP3+ regulatory T cells when cocultured with nonactivated peripheral blood T cells. Furthermore, when peripheral blood CD25high regulatory T cells (Tregs) were depleted from isolated CD3+ T cells, pericytes preferentially induced de novo formation of CD4+CD25highFoxP3+CD127−, suppressive regulatory T cells. Constitutive expression of PD-L1/2 and secretion of transforming growth factor-β by hPSC pericytes directly regulated generation of pericyte-induced Tregs. Pericytes cotransplanted into immunodeficient mice with allogeneic CD25− T cells maintained a nonimmunogenic phenotype and mediated the development of functional regulatory T cells. Together, these findings reveal a novel feature of pericyte-mediated immunomodulation distinguished from immunosuppression, shared by native tissue pericytes and hPSC pericytes, and support the notion that pericytes can be applied for allogeneic cell therapy.
A Piece of Paper and a Pair of Scissors
Authors: Claudiu Mihai  , Christine Rakowski
Published: September 2014

In this paper we will discuss the problem of splitting a given geometrical figure in two regions of equal area by drawing a line through a given point in the interior of the figure. For some geometric figures we will further discuss the possibility of splitting the figure in regions with areas p% and (100-p) %.
The effect of keel fractures on egg-production parameters, mobility and behaviour in individual laying hens
Authors: Nasr MAF , Murrell J , Wilkins LJ , Nicol CJ
Published: September 2014

A majority of laying hens fracture their keel bones during the laying cycle. It is not easy for a farmer to identify hens with fractures and hen survival rate seems high. Thus, the effect of both recent and healed fractures on bird welfare is unclear. We aimed to investigate the impact of these keel-bone fractures on hens’ production and behaviour. The egg production, mobility and behaviour of Lohmann Brown hens without keel fractures were compared with that of hens with old healed fractures of varying severity. In addition, the keel-bone strength and body temperature around the fracture site was measured for each group. Hens with no fractures laid more eggs and had a higher egg-quality score (derived from measures of egg weight, egg surface area, shell weight, shell percentage and shell density). These hens had the highest keel area temperature, strongest keel bones, accessed perches more frequently and took a shorter time to negotiate a walkway obstacle test and to fly down from a raised perch. Hens without keel fractures were better in all investigated parameters than hens with keel fractures, indicating a detrimental effect of fractures on both welfare and economic return.
Current use of and attitudes towards identification in cats and dogs in veterinary clinics in Oklahoma City, USA
Authors: Slater MR , Weiss E , Lord LK
Published: September 2014

Personalised identification (ID) tags that contain the contact information of pet owners can help ensure a pet gets home quickly. Recent research found that even though ID tags can help get pets home, the majority of pet owners do not consistently provide ID tags. The objectives of this study were to identify the number of animals at our study site wearing an ID tag as well as the owners’ reasons for not having them do so and to evaluate the attitudes and perceptions of owners towards pet identification. Pet owners were surveyed when visiting one of five veterinary hospitals and a low cost spay/neuter clinic in Oklahoma City, USA. Out of the 291 pets in the survey, only 59 (20.3%) were currently wearing an ID tag with correct information. When asked how important it was for pets to wear identification, 79.6% of the surveyed pet owners reported it was very or extremely important with only 0.7% reporting that ID tags were not at all important. The most common reason for not placing a tag on their pet was that their pet was ‘indoor only’ (35.3%), with another 10% reporting their pet did not wear ID because the pet was uncomfortable wearing a collar. The results of this research suggest that a high percentage of pets do not have ID tags and that a programme to place ID tags directly onto the pets has a good potential for success, as there is a positive attitude toward tagging among pet owners.
Ces lieux où ingénieurs et musiciens convergent
Authors: Palacio-Quintin Cléo
Published: September 2014

Particulièrement au cours du xxe siècle, le développement des technologies d’enregistrement du son, puis de l’informatique, ont révolutionné la pratique musicale de nombreux créateurs. Le musicien, intéressé par les possibilités sonores inouïes qu’offrent ces nouveaux outils, deviendra de plus en plus « technicien », « ingénieur » voire « programmeur », afin de réaliser ses oeuvres. La nécessité d’avoir accès à des équipements de pointe (au départ rares et très coûteux) et aux connaissances techniques pour s’en servir et les développer donne naissance à des centres de recherche et de création où vont se réunir ingénieurs et compositeurs. Cet article présente les premières institutions ayant posé d’importants jalons pour la discipline, en examinant particulièrement deux figures phares du développement de la musique-technologie, soit Pierre Schaeffer (grm, France) et Max Mathews (Bell Labs, États-Unis), souvent respectivement qualifiés de « pères » de la musique électroacoustique et de la musique informatique. Les collaborateurs privilégiés de Mathews sont également présentés : Jean-Claude Risset et John Chowning (de l’Université de Stanford). Des parties thématiques soulignent l’historique des tout premiers studios fondés au sein de radios d’État, ainsi que plusieurs autres fondés au sein des universités nord-américaines à partir des années 1950. Ce survol se termine sur des institutions françaises fondées au cours des années 1960 et 1970. Ces lieux pionniers ont tous engagé des activités de recherche et de création significatives, qui ont permis le développement d’outils technologiques pour la création musicale.
Conserved mechanisms of microtubule-stimulated ADP release, ATP binding, and force generation in transport kinesins
Authors: Atherton Joseph , Farabella Irene , Yu I-Mei , Rosenfeld Steven S , Houdusse Anne , Topf Maya , Moores Carolyn A
Published: September 2014

Kinesins are a superfamily of microtubule-based ATP-powered motors, important for multiple, essential cellular functions. How microtubule binding stimulates their ATPase and controls force generation is not understood. To address this fundamental question, we visualized microtubule-bound kinesin-1 and kinesin-3 motor domains at multiple steps in their ATPase cycles—including their nucleotide-free states—at ∼7 Å resolution using cryo-electron microscopy. In both motors, microtubule binding promotes ordered conformations of conserved loops that stimulate ADP release, enhance microtubule affinity and prime the catalytic site for ATP binding. ATP binding causes only small shifts of these nucleotide-coordinating loops but induces large conformational changes elsewhere that allow force generation and neck linker docking towards the microtubule plus end. Family-specific differences across the kinesin–microtubule interface account for the distinctive properties of each motor. Our data thus provide evidence for a conserved ATP-driven mechanism for kinesins and reveal the critical mechanistic contribution of the microtubule interface.
Mesoscale dynamics in the Arabian Sea and a focus on the Great Whirl life cycle: A numerical investigation using ROMS
Authors: Vic C. , Roullet G. , Carton X. , Capet X.
Published: September 2014

The Great Whirl (GW) is a persistent anticyclonic mesoscale eddy that is observed seasonally in the Arabian Sea during a period embedding the 3 months of the southwest monsoon (June–July–August) at a quasi‐steady location. Its dynamics remain unclear despite it being one of the largest coherent vortices in the world ocean. Realistic regional numerical experiments using ROMS are performed to investigate the life cycle of the GW, which is not well resolved by sparse available in situ measurements in the region. Using a set of sensitivity experiments and an accurate temporal characterization of the eddy properties (including position, radius, depth, and vorticity) we (i) confirm the role of basin‐scale downwelling Rossby waves in the GW generation, (ii) clarify the role of the monsoonal strong anticyclonic wind in its maintenance and barotropization, and (iii) suggest a connection between basin‐scale Rossby wave dynamics and GW collapse.
Quantifying tidally driven benthic oxygen exchange across permeable sediments: An aquatic eddy correlation study
Authors: McGinnis Daniel F. , Sommer Stefan , Lorke Andreas , Glud Ronnie N. , Linke Peter
Published: September 2014

Continental shelves are predominately (∼70%) covered with permeable, sandy sediments. While identified as critical sites for intense oxygen, carbon, and nutrient turnover, constituent exchange across permeable sediments remains poorly quantified. The central North Sea largely consists of permeable sediments and has been identified as increasingly at risk for developing hypoxia. Therefore, we investigate the benthic O2exchange across the permeable North Sea sediments using a combination of in situ microprofiles, a benthic chamber, and aquatic eddy correlation. Tidal bottom currents drive the variable sediment O2penetration depth (from ∼3 to 8 mm) and the concurrent turbulence‐driven 25‐fold variation in the benthic sediment O2uptake. The O2flux and variability were reproduced using a simple 1‐D model linking the benthic turbulence to the sediment pore water exchange. The high O2flux variability results from deeper sediment O2penetration depths and increased O2storage during high velocities, which is then utilized during low‐flow periods. The study reveals that the benthic hydrodynamics, sediment permeability, and pore water redox oscillations are all intimately linked and crucial parameters determining the oxygen availability. These parameters must all be considered when evaluating mineralization pathways of organic matter and nutrients in permeable sediments.
Changes in the composition of the northern polar upper stratosphere in February 2009 after a sudden stratospheric warming
Authors: Damiani Alessandro , Funke Bernd , López Puertas Manuel , Gardini Angela , von Clarmann Thomas , Santee Michelle L. , Froidevaux Lucien , Cordero Raul R.
Published: September 2014

Variability in the chemistry of the upper stratosphere/lower mesosphere region has been analyzed focusing on high latitudes during the boreal winter in 2009 characterized by the strong sudden stratospheric warming (SSW) on 24 January. Data from Michelson Interferometer for Passive Atmospheric Sounding aboard Envisat and the Microwave Limb Sounder on Aura have been used to exemplify these changes. Record high (low) values of O3 and ClO (temperature and HCl) for the winters of 2005–2012, coupled with a simultaneous enhancement of ClONO2, have been observed in February 2009. This suggests that the very low temperatures favor a more effective ozone production and a greater O3/O ratio. The latter is the main factor controlling active chlorine partitioning. Increases of ClO lead to high ClONO2 concentrations in the upper stratosphere at high latitudes, where its photodissociation rate is smaller. Since this increase of ClONO2 happens at the expense of HCl, the region of high ClONO2 roughly coincides with the region of low HCl. Although this period was characterized by an elevated stratopause event, the investigated region was not influenced by the descent of mesospheric air rich in NOx. Some limited enhancements in NOx at ~1 hPa occurred at latitudes greater than 80°N after about 20 February, but they became consistent only in March. Intrusion of midlatitude air mostly occurred between the SSW and early February. Then, the sum of volume mixing ratios of ClONO2 + ClO + HCl remained approximately constant and close to the values of the other years. In contrast, it was up to 0.2 ppbv lower during the SSW period. These atypical chemical conditions occurred also in February 2006, but 2009 stands out for its long‐lasting effects, which persisted until late March.
Aircraft soot indirect effect on large‐scale cirrus clouds: Is the indirect forcing by aircraft soot positive or negative?
Authors: Zhou Cheng , Penner Joyce E.
Published: September 2014

The indirect effect of aircraft soot on cirrus clouds is subject to large uncertainties due to uncertainty in the effectiveness of aircraft soot acting as heterogeneous ice nuclei (IN) and the complexity caused by background ice nucleation, which introduces two major competing ice nucleation mechanisms: homogeneous freezing that generally produces more abundant ice particles and heterogeneous nucleation that generally produces fewer ice particles. In this paper, we used the coupled Community Atmosphere Model version 5.2 (CAM5)/IMPACT model to estimate the climate impacts of aircraft soot acting as IN in large‐scale cirrus clouds. We assume that only the aircraft soot particles that are preactivated in persistent contrail cirrus clouds are efficient IN. Further, we assume that these particles lose their ability to act as efficient IN when they become coated with three monolayers of sulfate. We varied the background number concentration of sulfate aerosols allowed to act as homogeneous ice nucleation sites as well as the dust concentrations that act as heterogeneous ice nuclei to examine the sensitivity of the forcing by aircraft soot to the background atmosphere. The global average effect can range from a high negative (cooling) rate, −0.35 W m−2, for the high sulfate/low dust case to a positive (warming) rate, +0.09 W m−2, for the low sulfate/low dust case (default CAM5 setup) when approximately 0.6% of total aviation soot acts as IN. The net negative forcing is caused by the addition of IN to a background atmosphere that is dominated by homogeneous nucleation (mainly in the tropic Indian Ocean, Central America, and North Atlantic Ocean). The forcings can be all positive, about +0.11 to +0.21 W m−2, when the background atmosphere is dominated by pure heterogeneous ice nucleation.
Drought in the U.S. Great Plains (1980–2012): A sensitivity study using different methods for estimating potential evapotranspiration in the Palmer Drought Severity Index
Authors: Yuan Shanshui , Quiring Steven M.
Published: September 2014

The Palmer Drought Severity Index (PDSI) has been widely used to evaluate drought conditions since it was developed in 1965. In the original formulation of the PDSI, potential evapotranspiration (PET) was estimated using the Thornthwaite equation. This study evaluates how using more physically based approaches for estimating PET influences the depiction of drought conditions over the U.S. Great Plains from 1980 to 2012. Both the Penman‐Monteith equation and the two‐source PET model are compared to the original Thornthwaite‐based PDSI. The differences in PET between the three methods are much larger than the resulting differences in the PDSI. Results show that the original PDSI has a stronger drying trend than versions of PDSI that use more physically based methods of estimating PET. Spatially, all three versions of the PDSI show similar distributions of drying and wetting trends; however, there are significant regional variations that appear to be associated with land cover. PDSI and observed soil moisture in the top 1 m are moderately correlated (correlation coefficient is ~0.5) over the U.S. Great Plains, except in Texas (correlation coefficient is ~0.3). Although all three approaches result in a similar area‐averaged PDSI for the U.S. Great Plains, there are large differences in the area affected by drought, especially during extreme drought events.
Investigating ice nucleation in cirrus clouds with an aerosol‐enabled Multiscale Modeling Framework
Authors: Zhang Chengzhu , Wang Minghuai , Morrison Hugh , Somerville Richard C. J. , Zhang Kai , Liu Xiaohong , Li Jui‐Lin F.
Published: September 2014

In this study, an aerosol‐dependent ice nucleation scheme has been implemented in an aerosol‐enabled Multiscale Modeling Framework (PNNL MMF) to study ice formation in upper troposphere cirrus clouds through both homogeneous and heterogeneous nucleation. The MMF model represents cloud scale processes by embedding a cloud‐resolving model (CRM) within each vertical column of a GCM grid. By explicitly linking ice nucleation to aerosol number concentration, CRM‐scale temperature, relative humidity and vertical velocity, the new MMF model simulates the persistent high ice supersaturation and low ice number concentration (10–100/L) at cirrus temperatures. The new model simulates the observed shift of the ice supersaturation PDF toward higher values at low temperatures following the homogeneous nucleation threshold. The MMF model predicts a higher frequency of midlatitude supersaturation in the Southern Hemisphere and winter hemisphere, which is consistent with previous satellite and in situ observations. It is shown that compared to a conventional GCM, the MMF is a more powerful model to simulate parameters that evolve over short time scales such as supersaturation. Sensitivity tests suggest that the simulated global distribution of ice clouds is sensitive to the ice nucleation scheme and the distribution of sulfate and dust aerosols. Simulations are also performed to test empirical parameters related to auto‐conversion of ice crystals to snow. Results show that with a value of 250 μm for the critical diameter, Dcs, that distinguishes ice crystals from snow, the model can produce good agreement with the satellite‐retrieved products in terms of cloud ice water path and ice water content, while the total ice water is not sensitive to the specification of Dcs value.
Fabrication and Characterization of Organic Single Crystal‐Based Light‐Emitting Devices with Improved Contact Between the Metallic Electrodes and Crystal
Authors: Ding Ran , Feng Jing , Zhang Xu‐Lin , Zhou Wei , Fang Hong‐Hua , Liu Yue‐Feng , Chen Qi‐Dai , Wang Hai‐Yu , Sun Hong‐Bo
Published: September 2014

Organic single crystals have attracted great attention because of their advantages of high charge‐carrier mobility, high chemical purity, and potential for flexible optoelectronic devices. However, their intrinsic properties of sensitive to organic solvent and fragile result in a difficulty in the fabrication of the organic crystal‐based devices. In this work, a simple and non‐destructive technique of template stripping is employed to fabricate single‐crystal‐based organic light‐emitting devices (OLEDs). Efficient and uniform carrier injection induced by an improved contact between crystals and both top and bottom electrodes is realized, so that a homogeneous and bright electroluminescence (EL) are obtained. Highly polarized EL and even white emission is also observed. Moreover, the crystal‐based OLEDs exhibit good flexibility, and keep stable EL under a small bending radius and after repeated bending. It is expectable that this technique would support broad applications of the organic single crystals in the crystal‐based optoelectronic devices.
Delivery of iPS‐NPCs to the Stroke Cavity within a Hyaluronic Acid Matrix Promotes the Differentiation of Transplanted Cells
Authors: Lam Jonathan , Lowry William E. , Carmichael S. Thomas , Segura Tatiana
Published: September 2014

Stroke is the leading cause of adult disability with ≈80% being ischemic. Stem cell transplantation has been shown to improve functional recovery. However, the overall survival and differentiation of these cells is still low. The infarct cavity is an ideal location for transplantation as it is directly adjacent to the highly plastic peri‐infarct region. Direct transplantation of cells near the infarct cavity has resulted in low cell viability. Here, neural progenitor cells derived from induce pluripotent stem cells (iPS‐NPC) are delivered to the infarct cavity of stroked mice encapsulated in a hyaluronic acid hydrogel matrix to protect the cells. To improve the overall viability of transplanted cells, each step of the transplantation process is optimized. Hydrogel mechanics and cell injection parameters are investigated to determine their effects on the inflammatory response of the brain and cell viability, respectively. Using parameters that balanced the desire to keep surgery invasiveness minimal and cell viability high, iPS‐NPCs are transplanted to the stroke cavity of mice encapsulated in buffer or the hydrogel. While the hydrogel does not promote stem cell survival one week post‐transplantation, it does promote differentiation of the neural progenitor cells to neuroblasts.
Profile Control in Block Copolymer Nanostructures using Bilayer Thin Films for Enhanced Pattern Transfer Processes
Authors: He Chunlin , Stoykovich Mark P.
Published: September 2014

Although control over the domain orientation and long‐range order of block copolymer nanostructures self‐assembled in thin films has been achieved using various directed self‐assembly techniques, more challenging but equally important for many lithographic applications is the ability to precisely control the shape of the interface between domains. Here, a novel layer‐by‐layer approach is reported for controlling the interface profile of block copolymer nanostructures and the application of an undercut sidewall profile for an enhanced metal lift‐off process for pattern transfer is demonstrated. Bilayer films of lamellar‐forming poly(styrene‐block‐methyl methacrylate) are assembled and thermally cross‐linked on wafer substrates in a layer‐by‐layer process. The top layer, while being directed to self‐assemble on the lamellae of the underlying layer, has a tunable composition and polystyrene domain width independent of that of the bottom layer. Undercut or negative sidewall profiles in the PS nanostructures are proven to provide better templates for the lift‐off of Au nanowires by achieving complete and defect‐free pattern transfer more than three times faster than comparable systems with vertical sidewall profiles. More broadly, the layer‐by‐layer approach presented here provides a pathway to achieving sophisticated interface profiles and user‐defined 3D block copolymer nanostructures in thin films.
Elongation of Fibers from Highly Viscous Dextran Solutions Enables Fabrication of Rapidly Dissolving Drug Carrying Fabrics
Authors: Frampton John P. , Lai David , Lounds Maxwell , Chung Kyeongwoon , Kim Jinsang , Mansfield John F. , Takayama Shuichi
Published: September 2014

A simple method is presented for forming thread‐like fibers from highly viscous dextran solutions. Based on the cohesive and adhesive forces between a dextran solution and the substrate to which it is applied, multiple fibers of approximately 10 μm in diameter can be elongated simultaneously. These fibers can be woven into multiple layers to produce fabrics of varying fiber orientations and mechanical properties. Various bioactive agents can be incorporated into the dextran solution prior to fiber formation, including hemostatic and antibiotic agents. Fabrics containing thrombin are capable of coagulating human platelet poor plasma in vitro. Fabrics containing antibiotics are capable of suppressing bacterial growth in a disk diffusion assay. These data suggest that this new material composed entirely of dextran has promise as a drug delivery component in wound dressings.
Low Temperature Partial Oxidation of Methane over Bimetallic Nickel‐f Block Element Oxide Nanocatalysts
Authors: Branco Joaquim B. , Ferreira Ana C. , Gasche T. Almeida , Pimenta Gervásio , Leal João P.
Published: September 2014

The partial oxidation of methane (POM) was studied over bimetallic nickel‐f block element oxide nanocatalysts prepared by a modified sol‐gel method. They proved to be active (conversion of methane, 50–70%) at a relatively low temperatures (550 and 650 °C) and highly selective towards synthesis gas production (selectivity, H2 60–90% and CO 50–80%). The activity and selectivity depend on the surface basicity and size of the bimetallic oxide nanoparticles: lower particle size and higher basicity, enhanced activity and selectivity to synthesis gas. Catalysts reducibility seems as well to promote their activity and selectivity. The bimetallic nickel‐gadolinium and nickel‐thorium oxide nanocatalysts proved to be more active and selective towards synthesis gas production than a commercial platinum supported catalyst (5 wt% Pt/Al2O3) or other bimetallic nickel oxide catalysts obtained by a different high temperature preparation route, which stresses the advantage of the preparation method. The bimetallic nickel‐f block element oxide nanocatalysts present also remarkable long‐term stability and an unusual low deposition of carbon, which is a major advantage, especially when compared to other nickel‐based catalysts reported for POM. Such a behavior was attributed to the lanthanide or actinide oxide phases that appear to play an important role on the catalysts stability.

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Copper‐Catalyzed Regioselective Oxytrifluoromethylation of Allenes Using a CF3‐Transfer Reagent
Authors: Wang Yanan , Jiang Min , Liu Jin‐Tao
Published: September 2014

A mild and efficient copper‐catalyzed oxytrifluoromethylation of allenes is demonstrated. The reaction tolerates a range of substrates to give a series of trifluoromethylated derivatives in moderate to good yields. Two possible pathways were proposed based on the reaction results and control experiments.

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Synthesis of Isoquinolin‐4‐ols by Palladium‐Catalysed Intramolecular Nucleophilic Addition of Aryl Iodides to Aldehydes
Authors: Solé Daniel , Mariani Francesco , Fernández Israel
Published: September 2014

A palladium‐catalysed intramolecular nucleophilic addition of aryl iodides to aldehydes leading to tetrahydroisoquinolin‐4‐ols is reported. A variety of products were isolated in good to excellent yields. The joint experimental‐computational study shows that although two competitive reaction pathways can be promoted by Pd(0) starting from α‐(2‐iodobenzylamino)‐aldehydes, the selectivity of the process can be controlled by the proper selection of the base. While the nucleophilic addition of the aryl‐Pd(II) intermediate to the carbonyl group is selectively promoted by using the base triethylamine (Et3N), the CH bond activation at the formyl group competes with the nucleophilic addition only when the base is replaced by cesium carbonate (Cs2CO3).

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Chiral Bicyclic Imidazole Nucleophilic Catalysts: Design, Synthesis, and Application to the Kinetic Resolution of Arylalkylcarbinols
Authors: Zhang Zhenfeng , Wang Mo , Xie Fang , Sun Huai , Zhang Wanbin
Published: September 2014

A new type of chiral 5‐aminoimidazole nucleophilic catalyst, designated as Alkyl‐PDPI (PDPI=3‐pyrrolidinyl‐6,7‐dihydro‐5H‐pyrrolo[1,2‐a]imidazole), was rationally designed, synthesized and applied to the kinetic resolution of various arylalkylcarbinols with good to excellent enantioselectivities. In particular, for phenyl(tert‐butyl)methanol and 1‐mesitylethanol, the s factors are as high as 45 and 67, respectively. Additionally, this new kind of chiral imidazole catalyst also showed good enantioselectivity for heteroarylalkylcarbinols.

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Direct Synthesis of Pyrrolo[3,4‐c]quinolines from the Domino Reaction of Tosylmethyl Isocyanides and Aminochalcones
Authors: Hu Zhongyan , Li Yifei , Pan Ling , Xu Xianxiu
Published: September 2014

A tandem formal [3+2] cycloaddition/cyclization reaction of aminochalcones with tosylmethyl isocyanide derivatives was developed for the practical and convenient synthesis of diverse tricyclic pyrrolo[3,4‐c]quinolines in high to excellent yields. In this domino process, three new bonds and two rings are successively formed at ambient conditions.

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Minutes Synthesis of 1,4,5‐Trisubstituted 5‐Dialkylamino‐1,2,3‐triazoles by 1‐Copper(I)‐Alkyne Controlled Tandem Process
Authors: Wang Bo , Liu Nan , Chen Wenwen , Huang Dayun , Wang Xinyan , Hu Yuefei
Published: September 2014

In existing CuAAC methods, the 1,4,5‐trisubstituted 1,2,3‐triazole unit usually was synthesized by trapping the 5‐metal‐1,2,3‐triazole intermediate (M=Cu, Bi or Al) with an electrophile. But, no 1,4,5‐trisubstituted 5‐dialkylamino‐1,2,3‐triazole has yet been synthesized for unknown reasons. We found that this problem may be caused by the strong oxidizing property of the amine electrophile (R2N+) or by the low reactivity of the MC bond in the intermediate. However, when a polymeric complex 1‐copper(I)‐alkyne was used as a substrate, the highly reactive 5‐copper(I)‐1,2,3‐triazole intermediate formed smoothly in the presence of the amine electrophile (R2N+). Finally, the first general synthesis of 1,4,5‐trisubstituted 5‐dialkylamino‐1,2,3‐triazoles was developed via the tandem reaction of 1‐copper(I)‐alkynes with azides and then with O‐benzoyl hydroxylamines at room temperature which occurred within five minutes.

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