bluuebunny/crossref_metadata_2025 huggingface dataset:
Form Accuracy of Optical Mould Inserts Made from Rapidly Solidified Aluminium Alloys
Authors: Abou-El-Hossein Khaled
Published: August 2015

Plastic optical components and lenses produced in mass quantities are usually manufactured using high-precision plastic injection technology. For that, high-precision plastic moulds with aluminium optical inserts made with extremely high dimension accuracy and high optical surface quality are used. Ultra-high precision single-point diamond turning have been successfully used in shaping optical mould inserts from various aluminium grades such as traditional 6061. However, extreme care should be taking when selecting machining parameters in order to produce optically valid surfaces before premature tool wear takes place especially when the machined optical materials has inadequate machining database. The current experimental study looks at the effect of cutting conditions on optical surfaces made from aluminium. The study embarks on helping establish some diamond machining database that helps engineers select the most favourable cutting parameters. The papers reports on the accuracy and surface finish quality received on an optical surface made on mould inserts from a newly developed aluminium alloy. Rapidly solidified aluminium (RSA) grades have been developed recently to address the various problems encountered when being cut by single-point diamond turning operation. The material is characterised by its extremely fine grained microstructure which helps extend the tool life and produce optical surfaces with nanometric surface finish. It is found the RSA grades can be successfully used to replace traditional optical aluminium grades when making optical surfaces. Surface finishes of as low as 10 nanometres and form accuracy of less than one micron can be achieved on RSA.
Growth of Solidification Grain of Aluminum Alloy Near a Mold
Authors: Esaka Hisao , Kataoka Yoshimasa , Shinozuka Kei
Published: August 2015

Surface quality as well as internal quality of cast products of aluminum alloys are strongly affected by the process of initial solidification. Control of solidified structure in this region is therefore quite important. In order to understand the growth of solidified grain, crystallographic characterization has been performed using EBSD (Electron Backscattered Diffraction) in this study. Al-6 mass%Si alloy was cast at 750°C on the chill plate. Longitudinal cross section of solidified shell was analyzed. In the region of initial solidification, many small crystals nucleated on the mold surface. The crystallographic orientations of these grains were random. It is normally found that an unfavorable grain was eliminated by a favorable grain. However, occasionally, we have found that an unfavorable grain enlarged its size. In this case, dendrite, the growth direction of which was far from the heat flow direction, gradually changed its crystallographic orientation from unfavorable one to favorable one. The grain enlarged its size by multiplication of dendrite arms. Crystallographic orientation of dendrite changed little by little when it branched. This kind of phenomena may take place in unsteady condition, such as initial solidification region.
Melt Refining Technology of Highly-Contaminated Magnesium Alloy Scraps via a Sequential Refining Process
Authors: Koh Ki Ho , Moon Byoung Gi , You Bong Sun , Shin Kwang Seon , Kim Nack J. , Sohn K.Y.
Published: August 2015

Steering wheel and headlamp housing scrap are chosen as targets for the development of a refining technology for highly contaminated magnesium melt, because they contain abundant foreign materials, which have high potential to form non-metallic inclusions and to deteriorate the corrosion resistance of recycled alloys. A sequential melt treatment technology has been investigated for refining old scrap. The headlamp housing scrap composed of AZ91D magnesium alloy covered with phosphating and Al-Si deposition layers was successfully refined by repeating gas bubbling without flux addition, whereas prefiltering and fluxing were necessary to refine the steering wheel scrap composed of AM50A magnesium alloy containing 1% polyurethane. However, the corrosion rates of the recovered ingots from the headlamp housing were relatively higher than those from the steering wheel, likely due to the greater concentration of iron with the increased amount of flux.
Casting Development with a High Strength Aluminium Alloy
Authors: Ji Shou Xun , Yan Feng , Fan Zhong Yun
Published: August 2015

In the present paper, we introduce the development of casting an industrial component with a newly developed high strength aluminium alloy for high pressure die casting, including the introduction of property requirement, and the simulation results of temperature distribution, air entrapment, air pressure and the porosity potential in the casting, overflows and gating system. The microstructure and mechanical properties of the casting with satisfied quality are described under as-cast and heat-treated conditions.
Baffin Island sandurs: a study of Arctic fluvial processes
Authors: Church M
Published: August 2015

Valley sandurs forin the major postglacial physiographic feature in much of the Canadian A retie. The conditions favourable for sandur development: presence of an abundant supply of detrital material and the occurrence of relatively frequent floods competent to
move the material, are characteristic of proglacial and some periglacial environments. Nival floods, summer icemelt floods, and summer storm runoff generate significant sediment transport events. Storm runoff is particularly effective in the Arctic since there is little vegetation and the substrate
is frozen, so that a high proportion of rainfall runs off immediately. The distribution of runoff events shows a disproportionate number of moderately high flows. Occasionally, extreme floods occur, produced by catastrophi c drainage of ponded water from ice margins. Sediment is transported mainly
as bedload, though solution and sus - pended load are significant. Transport is much greater than the rate of primary detritus production as large volumes of glacially derived material are being redistributed. Sandur streams are wide and shallow, a characteristic of channels in which most sediment
moves as bedload. The major hydrauli c adjustment to increasing discharge is made by stream velocity, indicating a change in bed form associated with the rapid increase of sediment transport that results in a sharp decline in flow resistance. The long profiles of the streams are approximately
paraboli c: this form is probably conditioned by the nature of the aggradation on the surface as a whole. The sequence of pools and riffles along the channels constitutes a fundamental feature of the river. It appears to function as a regulator of energy expenditure in the stream and concomitantly
influences flow resistance and the movement and storage of sediment. The sandur surface is an aggradational feature. Erosion and deposition occur over wide areas during major floods. Change of stage is rapid so that deposition is often chaotic, and little internal structure occurs in many sediments.
Significant pattern is found only in the mean size and variance of coarse materials (cobbles), indicating dep os ition under conditions of declining competence down sandur.
Drift prospecting; geochemistry of eskers and till in permanently frozen terrain: District of Keewatin, Northwest Territories
Authors: Shilts W W
Published: August 2015

Geochemical results are reported for a program that compared samples collected from eskers and adjacent till in permanently frozen terrain. Contrasting effects of disturbance on the well- and poorly sorted sediments within the active (seasonally thawed) zone are
discussed. Trace element geochemistry of several textural and mineralogical fractions of each sample is reported, compared and explained. A previously known area of copper-nickel mineralization is clearly outlined by anomalies in various fractions of both till and esker samples. Other anomalies,
possibly related to unknown sources, are also described.
It is concluded that some potentially interesting ore minerals (sulphides and carbonates) are removed from the active zone of eskers and till by intense chemical weathering. Clays and secondary oxides that can scavenge cations released by this weathering are preferentially removed by surface runoff
from mud boils on till, but are retained within the porous structure of the thawed zone of eskers. Thus, silt and clay (-250 mesh) is recommended for analysis in esker samples but must be used with caution when analyzing t ill. Heavy mineral separates from near-surface esker and till samples from
permanently frozen terrain are not recommended for routine analysis. Micas, magnetite, clay, and rock fragments can reflect economically interesting mineralization, suggesting that some mineral phases in rocks adjacent to mineralized zones may be enriched in the cations characteristic of those
zones. This implies that a target for drift prospecting may be larger than the mineralized zone its e lf.
Investigation of error sources in regional inverse estimates of greenhouse gas emissions in Canada
Authors: Chan E. , Chan D. , Ishizawa M. , Vogel F. , Brioude J. , Delcloo A. , Wu Y. , Jin B.
Published: August 2015

Abstract. Inversion models can use atmospheric concentration measurements to estimate surface fluxes. This study is an evaluation of the errors in a regional flux inversion model for different provinces of Canada, Alberta (AB), Saskatchewan (SK) and Ontario (ON). Using CarbonTracker model results as the target, the synthetic data experiment analyses examined the impacts of the errors from the Bayesian optimisation method, prior flux distribution and the atmospheric transport model, as well as their interactions. The scaling factors for different sub-regions were estimated by the Markov chain Monte Carlo (MCMC) simulation and cost function minimization (CFM) methods. The CFM method results are sensitive to the relative size of the assumed model-observation mismatch and prior flux error variances. Experiment results show that the estimation error increases with the number of sub-regions using the CFM method. For the region definitions that lead to realistic flux estimates, the numbers of sub-regions for the western region of AB/SK combined and the eastern region of ON are 11 and 4 respectively. The corresponding annual flux estimation errors for the western and eastern regions using the MCMC (CFM) method are -7 and -3 % (0 and 8 %) respectively, when there is only prior flux error. The estimation errors increase to 36 and 94 % (40 and 232 %) resulting from transport model error alone. When prior and transport model errors co-exist in the inversions, the estimation errors become 5 and 85 % (29 and 201 %). This result indicates that estimation errors are dominated by the transport model error and can in fact cancel each other and propagate to the flux estimates non-linearly. In addition, it is possible for the posterior flux estimates having larger differences than the prior compared to the target fluxes, and the posterior uncertainty estimates could be unrealistically small that do not cover the target. The systematic evaluation of the different components of the inversion model can help in the understanding of the posterior estimates and percentage errors. Stable and realistic sub-regional and monthly flux estimates for western region of AB/SK can be obtained, but not for the eastern region of ON. This indicates that it is likely a real observation-based inversion for the annual provincial emissions will work for the western region whereas; improvements are needed with the current inversion setup before real inversion is performed for the eastern region.
Evaluation of social vulnerability to floods in Huaihe River basin: a methodology based on catastrophe theory
Authors: You W. J. , Zhang Y. L.
Published: August 2015

Abstract. Huaihe River is one of the seven largest rivers in China, in which floods occurred frequently. Disasters cause huge casualties and property losses to the basin, and also make it famous for high social vulnerability to floods. Based on the latest social-economic data, the index system of social vulnerability to floods was constructed, and Catastrophe theory method was used in the assessment process. The conclusion shows that social vulnerability as a basic attribute attached to urban environment, with significant changes from city to city across the Huaihe River basin. Different distribution characteristics are present in population, economy, flood prevention vulnerability. It is important to make further development of social vulnerability, which will play a positive role in disaster prevention, improvement of comprehensive ability to respond to disasters.
Using open building data in the development of exposure datasets for catastrophe risk modelling
Authors: Figueiredo R. , Martina M.
Published: August 2015

Abstract. One of the necessary components to perform catastrophe risk modelling is information on the buildings at risk, such as their spatial location, geometry, height, occupancy type and other characteristics. This is commonly referred to as the exposure model or dataset. When modelling large areas, developing exposure datasets with the relevant information about every individual building is not practicable. Thus, census data at coarse spatial resolutions are often used as the starting point for the creation of such datasets, after which disaggregation to finer resolutions is carried out using different methods, based on proxies such as the population distribution. While these methods can produce acceptable results, they cannot be considered ideal. Nowadays, the availability of open data is increasing and it is possible to obtain information about buildings for some regions. Although this type of information is usually limited and, therefore, insufficient to generate an exposure dataset, it can still be very useful in its elaboration. In this paper, we focus on how open building data can be used to develop a gridded exposure model by disaggregating existing census data at coarser resolutions. Furthermore, we analyse how the selection of the level of spatial resolution can impact the accuracy and precision of the model, and compare the results in terms of affected residential building areas, due to a flood event, between different models.
Efectividad de dos Formulaciones de Clethodim en el Control de Gramíneas y su Antagonismo con Bentazon
Authors: Espinoza Valdéz Elvis Erbuins , Pitty Abelino , Trabanino Rogelio
Published: August 2015

Los objetivos fueron evaluar la eficacia de las formulaciones Icasso 24 EC y Arrow 12 EC del herbicida Clethodim y determinar el antagonismo de ambas formulaciones con Bentazon. En dos experimentos se evaluó el control de malezas gramíneas y la fitotoxicidad al frijol, y en otro se evaluó el antagonismo al mezclar en el tanque el Clethodim (120 g de ingrediente activo por hectárea) con Bentazon (1,440 g de ingrediente activo por hectárea). En todos los experimentos se aplicó con una bomba de mochila de acero inoxidable modelo Tpresurizada con CO2 a una presión de 35 psi, un aguilón de 2 m de ancho con cuatro boquillas de abanico plano. En todos los ensayos se usó un diseño experimental de bloques completamente al azar y ninguno de los resultados de los testigos sin aplicación de herbicida, se usó en el análisis estadístico. La separación de medias fue con la prueba Duncan al 5%. En el primer ensayo, a las 2 semanas después de la aplicación, la formulación Icasso 24 EC tuvo 86% de control y para Arrow 12 EC fue 73%, ambas se aplicaron a 96 g del ingrediente activo por hectárea. En el segundo ensayo a las 3 semanas después de la aplicación, usando 96 g de ingrediente activo por hectárea, el control con  Icasso 24 EC fue 40% y con Arrow 12 EC 33%, al aumentar la dosis a 120 g el control fue 45% con Icasso 24 EC y 36% Arrow 12 EC. El control fue mayor  con Icasso 24 EC, que con Arrow 12 EC, por lo tanto, se atribuye la diferencia en el control de malezas a la formulación del herbicida, ya que los fabricantes añaden ingredientes inertes diferentes y algunos aumentan la eficacia del herbicida. En ninguna evaluación las formulaciones causaron fitotoxicidad al frijol. Esto indica que ninguna de las formulaciones ni los ingredientes inertes dañan al frijol. La evaluación del antagonismo fue un factorial y hubo diferencia estadística en el control entre las formulaciones y cuando las formulaciones se aplicaron solas o mezcladas con Bentazon. En ninguna evaluación hubo interacción, lo que indica que los factores (formulación y la mezcla con Bentazon) actúan independientemente. A las 3 semanas después de la aplicación, al mezclar Bentazon con Icasso 24 EC el control se redujo de 74 a 25%, una reducción de 66%. Al mezclar Bentazon con Arrow 12 EC el control se redujo de 60 a 11%, una reducción de 82%. El Bentazon es antagonista a las dos formulaciones, pero hubo mayor antagonismo o reducción en el control con Arrow 12 EC que con Icasso 24 EC.Ceiba, 2012. Volumen 53(1):57-64
ANÁLISE DA INFLUÊNCIA DO MERCADO FINANCEIRO SOBRE O MERCADO FUTURO AGROPECUÁRIO NO BRASIL
Authors: Araujo da Silva Viviane , Bornacki de Mattos Leonardo , Bragança Coelho Alexandre
Published: August 2015

A trajetória altista dos preços das commodities, iniciada em 2002, tem sido acompanhada pelo aumento do volume de negociações nos mercados futuros. Nesse contexto, a migração de investimentos dos mercados financeiros para os mercados futuros tem sido apontada como um dos fatores responsáveis pelo aumento dos preços e da volatilidade no mercado de alimentos. Isto posto, objetivou-se neste trabalho analisar a influência do mercado financeiro sobre o mercado futuro agropecuário no Brasil. Os resultados mostram ter ocorrido transmissão de volatilidade do mercado financeiro internacional para o mercado futuro de milho, café arábica e soja; e do mercado financeiro nacional para o mercado futuro de milho. Com exceção da relação Ibovespa-mercado futuro de boi gordo, não há relação de causalidade entre a volatilidade dos mercados, assim como não há relação linear causal partindo da variação de volume de contratos futuros negociados em direção aos retornos dos preços.
A REGULAÇÃO DO MERCADO DE SAÚDE E OS EFEITOS SOBRE A SELEÇÃO ADVERSA
Authors: Nunes Andre
Published: August 2015

O objetivo do artigo é verificar se após a adoção do novo marco regulatório para as operadoras de saúde no Brasil, com a proibição da seleção adversa, proibição da rescisão unilateral dos contratos e das limitações de carências, houve melhoria de bem-estar para os consumidores dos planos de saúde. Verificou-se que, embora ocorra seleção adversa nos dois períodos considerados, verifica-se um agravamento do problema após o advento da regulação.
TABAGISMO E EXTERNALIDADES DA ALFABETIZAÇÃO NO CEARÁ
Authors: Ribeiro Felipe Garcia , Carraro André
Published: August 2015

Este trabalho verifica se a presença de indivíduos alfabetizados em domicílios que residem indivíduos analfabetos é capaz de reduzir o hábito de tabagismo dos analfabetos no estado brasileiro do Ceará. Com informações da pesquisa especial da PNAD 2008 sobre tabagismo, a utilização do método de variáveis instrumentais encontrou evidências de que pessoas analfabetas que convivem com outras alfabetizadas tem em média uma menor probabilidade (variando de -9,5p.p a -7,0p.p) de ser fumante do que analfabetos que não convivem com pessoas alfabetizadas. Estes resultados são robustos às diferentes definições de alfabetização adotadas neste trabalho.
O IMPACTO DA PREFERÊNCIA PELA LIQUIDEZ NA DISPONIBILIDADE DE CRÉDITO DOS MUNICÍPIOS DO ESPÍRITO SANTO
Authors: Zambon Monte Edson , Almeida Viana Mirian
Published: August 2015

Eeste trabalho teve como objetivo geral identificar quais os impactos da preferência pela liquidez do público (PLP) e dos bancos (PLB) na disponibilidade de crédito nos municípios do Espírito Santo. Adotou-se a técnica econométrica de dados em painel pooled (empilhado). Os resultados obtidos para o período de 2005 a 2010 confirmaram que a PLB e a PLP afetam negativamente a oferta de crédito nos municípios do Espírito Santo, com maior influência da PLB do que da PLP. Além disso, verificou-se que a disponibilidade de crédito é maior nos municípios mais dinâmicos, ou seja, mais desenvolvidos. No mais, há evidências de que a preferência pela liquidez é um importante fator na explicação da tendência a concentração regional do crédito nos municípios capixabas.
Assessing the Condition of a Critical Supply Main
Authors: Byrne Kirstin , Cathcart James , Vanderschaaf Richard , Balotsky Yana
Published: August 2015

The city of San Diego retained an engineering firm to determine the condition and remaining useful life of the city's 75‐year old El Monte raw water transmission main. The pipeline was evaluated in phases, using both intrusive and nonintrusive methods.
Real‐Time Modeling Improves Operations
Authors: Smith Ron
Published: August 2015

Colorado Springs (Colo.) Utilities has begun transitioning from a traditional water model to a real‐time water model. Near the finish of a major pipeline installation, the utility sought better understanding of the new water source's effect on the distribution system. Real‐time modeling effectively depicts the pipeline in operation and provides additional benefits.
Enhancing Water Recovery Sustainably
Authors: Cappelle Malynda A. , Alspach Brent , Gilron Jack , Russell Caroline , Davis Thomas A.
Published: August 2015

Several US cities are turning to brackish groundwater and municipal wastewater to supplement their dwindling drinking water supplies. Desalination is a reliable technique for producing potable water but can be limited by a lack of suitable concentrate‐disposal options and land area. New technologies offer approaches for heightened recovery and evaporation to meet these challenges.
Clarification conceptuelle autour de la notion de culture dans le cadre d’une recherche inductive sur l’enseignant togolais
Authors: Hamelin Émilie
Published: August 2015

Cet article porte sur la pertinence d’utiliser, en amont d’une démarche de collecte de données, un cadre conceptuel dans une recherche adoptant une approche inductive. Les résultats présentés reposent sur l’expérience concrète d’une recherche réalisée sur le sol africain et qui porte sur les enseignants togolais en tant que passeurs culturels. L’objectif était d’explorer l’expérience des enseignants togolais oeuvrant dans des écoles primaires publiques du Togo, spécifiquement sur leur fonction de passeur culturel. Afin d’appréhender le phénomène tel qu’il est vécu par les enseignants togolais, nous avons dû opérer une clarification conceptuelle autour du concept de passeur culturel parce que nous avons eu besoin de bien cerner l’objet de recherche lui-même. Par la suite, nous avons pu analyser le vécu de la tâche de passeur culturel comme elle se traduit non seulement dans le discours de l’enseignant, mais aussi dans sa pratique en classe.
Tentative de renouvellement de l’approche méthodologique en marketing social : l’apport de la MTE dans un effort de sensibilisation des jeunes conducteurs québécois à la problématique de l’alcool au volant
Authors: Boivin1 Maxime
Published: August 2015

L’intégration de la méthodologie de la théorisation enracinée (MTE) à la recherche en marketing social, et plus particulièrement en sécurité routière, est une orientation méthodologique plutôt récente. Nous croyons pourtant que cette approche, qui est à l’antithèse de l’approche hypothético-déductive traditionnellement répandue dans ce domaine, est la plus appropriée pour nous permettre de répondre à la question suivante : comment sensibiliser et éduquer les jeunes conducteurs québécois de 18 à 24 ans aux problèmes de l’alcool au volant? L’approche de la MTE nous fera ainsi mieux comprendre les perceptions qu’ont les jeunes conducteurs de l’alcool au volant puis nous permettra d’identifier les variables et les facteurs d’influence à considérer lors de l’élaboration et de la mise en oeuvre d’interventions visant à sensibiliser et à éduquer ce public cible à la problématique de l’alcool au volant. Dans cet article, nous présenterons la démarche inductive adoptée dans le cadre de notre projet de recherche portant sur la sensibilisation à l’alcool au volant auprès des jeunes conducteurs québécois (en cours) ainsi que les arguments appuyant ce choix.
Community radio, democratic participation and the public sphere
Authors: Gaynor Niamh , O’Brien Anne
Published: August 2015

Community radio is unique when compared to its commercial and public service counterparts in that, as a non-profit activity, it is owned, managed and controlled by local communities, In theory therefore, community radio offers the potential for more broad-based participation in deliberation and debate within the public sphere engaging multiple voices and perspectives and contributing towards progressive social change. Drawing on a study of four community radio stations in Ireland within a framework drawn from the evolving work of Habermas and associated deliberative, social and media theorists, in this article we examine the extent to which this is the case in practice. We find that democratic participation is still not optimised within the four stations studied. We argue that the reasons for this lie in four main areas: a somewhat limited policy framework; a focus within training programmes on technical competencies over content; the weakness of linkages between stations and their local community groups; and the failure of the latter to understand the unique remit of community radio. The article draws lessons of specific interest to researchers and activists in these domains, as well as offering a framework to those interested in examining community media’s contribution to the re-animation of the public sphere more broadly.
The principle of recognition: the people, state universality and the Good Friday Agreement
Authors: Byrne Michael
Published: August 2015

The article contributes to debates on the relationship between the state and ‘the people’ in post-national contexts, specifically those characterised by intra-state conflicts. The article critically theorises the articulation of this relationship in the Good Friday Agreement as part of the Northern Irish peace process. It employs the concept of ‘state universality’ to examine the way in which the state-people relationship is constructed on the basis of the recognition of multiple peoples, establishing the universality of the state in a postnational fashion. The article also draws on the work of Claude Lefort to examine the implications of this form in terms of political representation, arguing that the recognition of multiple peoples at stake in the Good Friday Agreement is predicated on the particularisation of the two communities, thus divesting political representation of the dimension of universality.
Trends, frames and discourse networks: analysing the coverage of climate change in Irish newspapers
Authors: Wagner Paul , Payne Diane
Published: August 2015

This paper investigates how anthropogenic climate change is presented to the Irish public by three of Ireland’s most important national newspapers. We argue that Irish newspapers do not report climate change in an objective and unbiased way and illustrate how through the acts of agenda setting, news framing and in how they construct public discourse they present the issue in a narrow ideological form. Evidence is provided to support the argument that ecological modernisation is used by Irish newspapers to construct the issue of climate change. Our study uses three levels of analysis: (1) we calculate the trend in the coverage of climate change between 1997 and 2012 to uncover what events are correlated with peaks in coverage; (2) we conduct an in-depth frame analysis of a large sample of articles to determine how the issue is classified and categorised; and (3) we conduct a discourse network analysis to uncover which actors are given a voice, which policy measures they favour and with whom they share policy positions. The data we find support our theoretical arguments, leading us to the conclusion that Irish newspapers produce and reproduce a narrow ideological worldview that is articulated, shared and propagated by Ireland’s political and economic elites.
A etnocenologia e seu método: pesquisa contemporânea em artes cênicas
Authors: Santos Adailton
Published: August 2015

A obra integra a coleção Pesquisa em Arte e se insere num processo de estudos sobre formas e padrões de pesquisa em artes cênicas. Um dos temas centrais abordados corresponde ao conjunto de eventos em torno dos quais se deu a constituição de uma nova disciplina científica: a etnocenologia. O autor baseia-se em três constantes para analisá-la: a relação sujeito/ objeto; o aparato linguístico a que se refere essa relação e o quadro epistêmico geral.
Phase-amplitude coupling supports phase coding in human ECoG
Authors: Watrous Andrew J , Deuker Lorena , Fell Juergen , Axmacher Nikolai
Published: August 2015

Prior studies have shown that high-frequency activity (HFA) is modulated by the phase of low-frequency activity. This phenomenon of phase-amplitude coupling (PAC) is often interpreted as reflecting phase coding of neural representations, although evidence for this link is still lacking in humans. Here, we show that PAC indeed supports phase-dependent stimulus representations for categories. Six patients with medication-resistant epilepsy viewed images of faces, tools, houses, and scenes during simultaneous acquisition of intracranial recordings. Analyzing 167 electrodes, we observed PAC at 43% of electrodes. Further inspection of PAC revealed that category specific HFA modulations occurred at different phases and frequencies of the underlying low-frequency rhythm, permitting decoding of categorical information using the phase at which HFA events occurred. These results provide evidence for categorical phase-coded neural representations and are the first to show that PAC coincides with phase-dependent coding in the human brain.
Rapid learning in visual cortical networks
Authors: Wang Ye , Dragoi Valentin
Published: August 2015

Although changes in brain activity during learning have been extensively examined at the single neuron level, the coding strategies employed by cell populations remain mysterious. We examined cell populations in macaque area V4 during a rapid form of perceptual learning that emerges within tens of minutes. Multiple single units and LFP responses were recorded as monkeys improved their performance in an image discrimination task. We show that the increase in behavioral performance during learning is predicted by a tight coordination of spike timing with local population activity. More spike-LFP theta synchronization is correlated with higher learning performance, while high-frequency synchronization is unrelated with changes in performance, but these changes were absent once learning had stabilized and stimuli became familiar, or in the absence of learning. These findings reveal a novel mechanism of plasticity in visual cortex by which elevated low-frequency synchronization between individual neurons and local population activity accompanies the improvement in performance during learning.
Nemo-like kinase is a novel regulator of spinal and bulbar muscular atrophy
Authors: Todd Tiffany W , Kokubu Hiroshi , Miranda Helen C , Cortes Constanza J , La Spada Albert R , Lim Janghoo
Published: August 2015

Spinal and bulbar muscular atrophy (SBMA) is a progressive neuromuscular disease caused by polyglutamine expansion in the androgen receptor (AR) protein. Despite extensive research, the exact pathogenic mechanisms underlying SBMA remain elusive. In this study, we present evidence that Nemo-like kinase (NLK) promotes disease pathogenesis across multiple SBMA model systems. Most remarkably, loss of one copy of Nlk rescues SBMA phenotypes in mice, including extending lifespan. We also investigated the molecular mechanisms by which NLK exerts its effects in SBMA. Specifically, we have found that NLK can phosphorylate the mutant polyglutamine-expanded AR, enhance its aggregation, and promote AR-dependent gene transcription by regulating AR-cofactor interactions. Furthermore, NLK modulates the toxicity of a mutant AR fragment via a mechanism that is independent of AR-mediated gene transcription. Our findings uncover a crucial role for NLK in controlling SBMA toxicity and reveal a novel avenue for therapy development in SBMA.
Distinct regulation of dopamine D2S and D2L autoreceptor signaling by calcium
Authors: Gantz Stephanie C , Robinson Brooks G , Buck David C , Bunzow James R , Neve Rachael L , Williams John T , Neve Kim A
Published: August 2015

D2 autoreceptors regulate dopamine release throughout the brain. Two isoforms of the D2 receptor, D2S and D2L, are expressed in midbrain dopamine neurons. Differential roles of these isoforms as autoreceptors are poorly understood. By virally expressing the isoforms in dopamine neurons of D2 receptor knockout mice, this study assessed the calcium-dependence and drug-induced plasticity of D2S and D2L receptor-dependent G protein-coupled inwardly rectifying potassium (GIRK) currents. The results reveal that D2S, but not D2L receptors, exhibited calcium-dependent desensitization similar to that exhibited by endogenous autoreceptors. Two pathways of calcium signaling that regulated D2 autoreceptor-dependent GIRK signaling were identified, which distinctly affected desensitization and the magnitude of D2S and D2L receptor-dependent GIRK currents. Previous in vivo cocaine exposure removed calcium-dependent D2 autoreceptor desensitization in wild type, but not D2S-only mice. Thus, expression of D2S as the exclusive autoreceptor was insufficient for cocaine-induced plasticity, implying a functional role for the co-expression of D2S and D2L autoreceptors.
Unified pre- and postsynaptic long-term plasticity enables reliable and flexible learning
Authors: Costa Rui Ponte , Froemke Robert C , Sjöström P Jesper , van Rossum Mark CW
Published: August 2015

Although it is well known that long-term synaptic plasticity can be expressed both pre- and postsynaptically, the functional consequences of this arrangement have remained elusive. We show that spike-timing-dependent plasticity with both pre- and postsynaptic expression develops receptive fields with reduced variability and improved discriminability compared to postsynaptic plasticity alone. These long-term modifications in receptive field statistics match recent sensory perception experiments. Moreover, learning with this form of plasticity leaves a hidden postsynaptic memory trace that enables fast relearning of previously stored information, providing a cellular substrate for memory savings. Our results reveal essential roles for presynaptic plasticity that are missed when only postsynaptic expression of long-term plasticity is considered, and suggest an experience-dependent distribution of pre- and postsynaptic strength changes.
Avaliação de biótipos de leiteiro com suspeita de resistência a herbicidas inibidores da ALS e Protox
Authors: Prigol Alana , Galon Leandro , Forte César Tiago , Kujawiski Renato , Concenço Germani , Trezzi Michelangelo Muzell , Trevisol Ricardo , Radünz André Luiz , Perin Gismael Francisco
Published: August 2015

Objetivou-se com o presente trabalho avaliar a confirmação da ocorrência de resistência de biótipos de leiteiro, oriundos de Rondônia e do Rio Grandes do Sul a herbicidas com diferentes mecanismos de ação, bem como determinar a dose dos herbicidas necessária para redução de 50% na massa seca das plantas (GR50) e para o controle de 50% das plantas de cada unidade experimental (C50). Para tanto foi instalado um experimento em casa de vegetação, em blocos casualizados, com quatro repetições. Os herbicidas utilizados foram: imazethapyr, chlorimuron-ethyl, cloransulam-methyl, saflufenacil, fomesafen e carfentrazone-ethyl. As doses utilizadas foram: 0; 0,5; 2; 8; 16; 32 e 64 vezes a dose comercial. As variáveis avaliadas foram controle do leiteiro aos 07, 14, 21 e 28 dias após a aplicação dos tratamentos (DAT) e também, aos 28 DAT determinou-se a massa seca das plantas. O biótipo do Rio Grande do Sul mostrou sensibilidade aos herbicidas testados, já o de Rondônia apresentou resistência cruzada aos inibidores de ALS (imazethapyr, chlorimuron e cloransulam) e suscetível aos inibidores de PROTOX (carfentrazone, fomesafen e saflufenacil).
Coronal Axis Measurement of the Optic Nerve Sheath Diameter Using a Linear Transducer
Authors: Amini Richard , Stolz Lori A. , Patanwala Asad E. , Adhikari Srikar
Published: August 2015

Objectives

The true optic nerve sheath diameter cutoff value for detecting elevated intracranial pressure is variable. The variability may stem from the technique used to acquire sonographic measurements of the optic nerve sheath diameter as well as sonographic artifacts inherent to the technique. The purpose of this study was to compare the traditional visual axis technique to an infraorbital coronal axis technique for assessing the optic nerve sheath diameter using a high‐frequency linear array transducer.

Methods

We conducted a cross‐sectional study at an academic medical center. Timed optic nerve sheath diameter measurements were obtained on both eyes of healthy adult volunteers with a 10–5‐MHz broadband linear array transducer using both traditional visual axis and coronal axis techniques. Optic nerve sheath diameter measurements were obtained by 2 sonologists who graded the difficulty of each technique and were blinded to each other's measurements for each participant.

Results

A total of 42 volunteers were enrolled, yielding 84 optic nerve sheath diameter measurements. There were no significant differences in the measurements between the techniques on either eye (P = .23 [right]; P = .99 [left]). Additionally, there was no difference in the degree of difficulty obtaining the measurements between the techniques (P = .16). There was a statistically significant difference in the time required to obtain the measurements between the traditional and coronal techniques (P < .05).

Conclusions

Infraorbital coronal axis measurements are similar to measurements obtained in the traditional visual axis. The infraorbital coronal axis technique is slightly faster to perform and is not technically challenging.
Obstetric and Gynecologic Resident Ultrasound Education Project
Authors: Green Jessica , Kahan Meldon , Wong Suzanne
Published: August 2015

Objectives

Ultrasound is a critical diagnostic imaging tool in obstetrics and gynecology (Ob/Gyn). Obstetric ultrasound is taught during residency, but we suspected a gap in Gyn ultrasound education. Proficiency in Gyn ultrasound allows real‐time interpretation and management of pelvic disease and facilitates technical skill development for trainees learning blinded procedures. This study sought to evaluate ultrasound education in Canada's Ob/Gyn residency programs and assess whether residents and physicians perceived a need for a formalized Gyn ultrasound curriculum.

Methods

We distributed a needs assessment survey to residents enrolled in Canadian Ob/Gyn residency programs and to all obstetrician/gynecologists registered as members of the Society of Obstetricians and Gynaecologists of Canada. Residents were asked to specify their current training in ultrasound and to rate the adequacy of their curriculum. All respondents rated the importance of proficiency in pelvic ultrasound for practicing obstetrician/gynecologists as well as the perceived need for formalized ultrasound training in Ob/Gyn residency programs.

Results

Eighty‐two residents and 233 physicians completed the survey. Extents and types of ultrasound training varied across residency programs. Most residents reported inadequate exposure to Gyn ultrasound, and most residents and physicians agreed that it is important for obstetrician/gynecologists to be proficient in Gyn ultrasound and that the development of a standardized Gyn ultrasound curriculum for residency programs is important.

Conclusions

Current ultrasound education in Ob/Gyn varies across Canadian residency programs. Training in Gyn ultrasound is lacking, and both trainees and physicians confirmed the need for a standardized Gyn ultrasound curriculum for residency programs in Canada.
Local Recurrent Phyllodes Tumors of the Breast
Authors: Xiao Mengsu , Zhu Qingli , Jiang Yuxin , Li Jianchu , Wang Hongyan , Zhang Jing , You Shanshan , Liu He
Published: August 2015

Objectives

The purpose of this study was to investigate the clinical, pathologic, and sonographic features of local recurrent phyllodes tumors of the breast and provide evidence for diagnosing tumor recurrence.

Methods

A total of 127 patients with phyllodes tumors who underwent surgery from 1993 to 2012 were followed. The clinical, pathologic, and sonographic features of local recurrent tumors were analyzed.

Results

Of the 127 patients, pathologic diagnoses were benign, borderline, and malignant in 75 (59.1%), 41 (32.3%), and 11 (8.7%) patients, respectively. The patients were followed for a mean duration ± SD of 50.9 ± 42.1 months (range, 2–225 months). Twenty‐one patients had local recurrence, for a recurrence rate of 16.5%. The benign, borderline, and malignant recurrence rates were 14.7%, 17.1%, and 27.3%. The local recurrence in the 21 patients occurred after a mean interval of 19.4 ± 13.4 months. The mean times to local recurrence were 20.2 ± 12.1, 16.9 ± 10.8, and 20.3 ± 19.0 months for benign, borderline, and malignant tumors. The histologic characteristics of the recurrent tumors were similar to those of the initial tumors in 14 patients (66.7%), whereas the characteristics changed in 7 (33.3%). The sonographic features of the recurrent tumors were as follows: 69.4% were lobulated; 88.9% appeared as well‐defined lesions; 41.7% had posterior acoustic enhancement; 11.1% had intramural cystic areas; and 83.4% had moderate or marked blood flow.

Conclusions

The recurrence rate for phyllodes tumors is high. One to 2 years after surgery is the key time for follow‐up. The sonographic features contribute to recurrence diagnosis.
Increased influence of nitrogen limitation on CO2 emissions from future land use and land use change
Authors: Meiyappan Prasanth , Jain Atul K. , House Joanna I.
Published: August 2015

In the latest projections of future greenhouse gas emissions for the Intergovernmental Panel on Climate Change (IPCC), few Earth System Models included the effect of nitrogen limitation, a key process limiting forest regrowth. Few included forest management (wood harvest). We estimate the impacts of nitrogen limitation on the CO2 emissions from land use and land use change (LULUC), including wood harvest, for the period 1900–2100. We use a land surface model that includes a fully coupled carbon and nitrogen cycle and accounts for forest regrowth processes following agricultural abandonment and wood harvest. Future projections are based on the four Representation Concentration Pathways used in the IPCC Fifth Assessment Report, and we account for uncertainty in future climate for each scenario based on ensembles of climate model outputs. Results show that excluding nitrogen limitation will underestimate global LULUC emissions by 34–52 PgC (20–30%) during the 20th century (range across three different historical LULUC reconstructions) and by 128–187 PgC (90–150%) during the 21st century (range across the four IPCC scenarios). The full range for estimated LULUC emissions during the 21st century including climate model uncertainty is 91 to 227 PgC (with nitrogen limitation included). The underestimation increases with time because (1) projected annual wood harvest rates from forests summed over the 21st century are 380–1080% higher compared to those of the 20th century, resulting in more regrowing secondary forests; (2) nitrogen limitation reduces the CO2 fertilization effect on net primary production of regrowing secondary forests following wood harvest and agricultural abandonment; and (3) nitrogen limitation effect is aggravated by the gradual loss of soil nitrogen from LULUC disturbance. Our study implies that (1) nitrogen limitation of CO2 uptake is substantial and sensitive to nitrogen inputs; (2) if LULUC emissions are larger than previously estimated in studies without nitrogen limitation, then meeting the same climate mitigation target would require an equivalent additional reduction of fossil fuel emissions; (3) the effectiveness of land‐based mitigation strategies will critically depend on the interactions between nutrient limitations and secondary forests resulting from LULUC; and (4) it is important for terrestrial biosphere models to consider nitrogen constraint in estimates of the strength of future land carbon uptake.
Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary
Authors: Nowacki Daniel J. , Ogston Andrea S. , Nittrouer Charles A. , Fricke Aaron T. , Van Pham Dang Tri
Published: August 2015

A better understanding of flow and sediment dynamics in the lowermost portions of large‐tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended‐sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal and low‐seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s−1during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s−1during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr−1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high‐flow sediment export. Exchange‐flow and tidal processes, including local resuspension, were principally responsible for the low‐flow import. The resulting bed‐sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid‐channel islands.