bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Outcomes of Staged Basilic Vein Transposition for Hemodialysis Access in Children
Authors: Kfoury Elias , Demaree Christopher J. , Poi Mun J. , Matos Jesus M. , Bechara Carlos F. , Lin Peter H.
Published: August 2017

Introduction

Children requiring long-term hemodialysis often face significant challenges due to their young age and small-vessel caliber for arteriovenous (AV) access creation. In this study, we report our experience of staged basilic vein transposition (BVT) in pediatric patients.

Methods

All patients undergoing staged BVT at a tertiary care pediatric hospital from 2003 to 2015 were reviewed. Indications for staged BVT included inadequate cephalic conduit or failed AV fistula using cephalic vein. Pertinent clinical variables were analyzed to determine treatment outcomes.

Results

Forty-two children (24 males, 57%) underwent 46 staged BVT during the study period. Median age was 12.8 ± 4.8 years (range 3-18). The mean weight was 47 ± 5.1 kg (range, 13-126 kg), with four children (10%) weighing ≤20 kg. Mean operative times for initial brachiobasilic AV fistula and staged BVT were 39 ± 12 minutes and 66 ± 17 minutes, respectively. Mean follow-up period was 5.4 ± 1.8 years. Functional maturation was achieved in 93% of BVTs. Early fistula thrombosis within 30 days following BVT occurred in four patients (10%). Late BVT thrombosis occurred in 13 patients (31%). Primary patency rates at 2 years and 4 years were 78% and 72%, respectively. Secondary patency rates at 2 years and 4 years were 86% and 82%, respectively.

Conclusions

Staged BVT is a durable and reliable autologous hemodialysis access in children who do not have adequate cephalic venous conduit.
Management of Hypertension in Patients during Percutaneous Dialysis Access Interventions
Authors: Gandhi Bhavika V. , Patel Tejas B. , Costanzo Eric J. , Masud Avais , Mehandru Sushil , Salman Loay
Published: August 2017

Not infrequently, interventionalists are faced with a patient with increased blood pressure who is about to undergo a dialysis access intervention such as tunneled hemodialysis catheter, percutaneous balloon angioplasty, or declotting procedure for a clotted arteriovenous access. This can frequently create a dilemma as functional dialysis access is needed to provide dialysis therapy and delaying treatment could result in a life-threatening situation, particularly in the presence of hyperkalemia. This article investigates hypertension in patients undergoing percutaneous dialysis access interventions and provides guidance to their management.
Quality, Rhetoric, and Choric Regression: Revisiting Zen and the Art of Motorcycle Maintenance
Authors: Frentz Thomas
Published: August 2017

In this article, I reexamine quality and rhetoric in Robert M. Pirsig's Zen and the Art of Motorcycle Maintenance through Julia Kristeva's semiotic chora. To that end, I review three analyses of Pirsig's novel, reinscribe quality as a prediscursive experience of undifferentiated wholeness, argue that regression back into Kristeva's chora is one way to recover this prediscursive experience, and hypothesize that the rhetoric of Zen is an unstable discourse in which prediscursive energies from the chora disrupt and realign the meanings of signifiers. I conclude by generalizing my work beyond Pirsig's novel to three concepts in rhetorical scholarship.
Logistics Research: What a Long, Strange Trip It's Been
Authors: Daugherty Patricia , Bolumole Yemisi , Schwieterman Matthew
Published: August 2017

This article reviews and reports on how academic logistics research has changed over the years, with particular emphasis on how these trends influence logistics educators and doctoral programs. Logistics‐related topics, the theories employed, and commonly used methods are examined. The article provides a juxtaposition of a historical perspective with recent research trends covering the period 2006–15. Implications for future logistics research and logistics doctoral programs are also discussed.
Order Crossover Research: A 60‐Year Retrospective to Highlight Future Research Opportunities
Authors: Saldanha John Patrick , Swan Peter
Published: August 2017

We review the literature spanning 60 years of efforts to model the phenomenon of order crossover. The importance of this research has increased due to today's longer ocean supply chains, with their greater inherent uncertainty. The incidence of order crossover is higher in these supply chains, and ignoring it will result in overestimation of safety stock. The literature is grouped into four areas, which are described separately, and is mapped to reveal gaps. Gaps exist for combinations of lead time distributions, demand distributions, and inventory policies where extant methods do not address order crossover. The effective lead time approach has proven flexible enough to be used in a wide range of periodic review situations. However, our results show that its accuracy is undermined by bimodal skewed lead‐time distributions, especially when lower bounds are nonzero. Future research needs to concentrate on exploring nonparametric methods or similar methods robust to different lead time distribution assumptions to provide a method of setting safety stock in “real world” situations where orders cross.
Applying Theories from Other Disciplines to Logistics and Supply Chain Management: A Systematic Literature Review
Authors: Swanson David , Goel Lakshmi , Francisco Kristoffer , Stock James
Published: August 2017

This systematic literature review focuses on theory‐driven research in logistics and supply chain management (LSCM), giving particular attention to the originating disciplines of theories used. It is important to understand the origin of theory and how it has evolved within the LSCM discipline, because learning the past helps scholars understand the present and presage the future. To fulfill that objective, this research catalogs theories that have been used and also begins to identify how, when, and why borrowed theories have been adapted for LSCM research. The major results include theoretical insights such as trends in theory utilization and the methods and topics where theories are typically used or underused. The top five theories that have been used in LSCM research actually represent five different disciplines—management, economics, mathematics, psychology, and sociology—supporting the multidisciplinary nature of LSCM. To summarize this research, a forward‐looking perspective is taken to identify potential areas for the application of theory for future LSCM research. Comments are also provided on how researchers are employing more theory in the latest period of LSCM development (2011–2015).
Perspective and the future-in-the-past
Authors: Eckardt Regine
Published: August 2017

The paper investigates the future-in-the-past (FiP) as in Peter would (later) see the Fujiyama. FiP can convey an outlook on events that, as the speaker knows, took place later (“objective sense”). FiP can also convey a past utterance or thought of a protagonist. In this perspective-taking sense, FiP sentences share the uncertainty about the future of present tense will-sentences. Kaufmann’s (2005) semantic treatment of the future is extended to account for shifted senses of the future-in-the-past, leading to the insight that tense scopes differently in non-shifted and shifted future-in-the-past. A final outlook speculates about more radical changes in the analysis of tense and aspect in order to account for this observation. This article is part of the special collection: Perspective Taking
Constraints in contact: Animacy in English and Afrikaans genitive variation – a cross-linguistic perspective
Authors: Rosenbach Anette
Published: August 2017

This paper builds on the observation that the animacy effects we find in English genitive variation are part of a larger cross-linguistic pattern as reflected in possession splits based on animacy (Koptjevskaja-Tamm 2001, 2002; Stolz et al. 2008), which are an expression of harmonic alignment in the domain of possession (Aissen & Bresnan 2002; Rosenbach 2008). Focussing on English and Afrikaans, a contrastive corpus analysis of genitive variation reveals similar forms of animacy splits in these two languages, though they differ in the strength of the animacy constraint, with the Afrikaans prenominal possessive (the se-genitive) occurring more freely with inanimate possessors than the English s-genitive. In a follow-up experimental study it is then shown that the weaker animacy constraint in Afrikaans carries over to the L2 English of Afrikaans speakers in South Africa. This study emphasizes the importance of a cross-linguistic perspective when looking at genitive variation in English and its varieties (1) to recognize that Englishes form part of a typological continuum of possession splits, and (2) to enable us to identify the possible transfer of constraint strengths from one language to another one in a situation where these languages are in contact, as in the case of English and Afrikaans in South Africa.This article is part of the Special Collection: Probabilistic grammars: Syntactic variation in a comparative perspective
Yield, flesh parameters, and proximate and fatty acid composition in muscle tissue of wild and cultured Vieja Colorada (Cichlasoma festae) in tropical Ecuadorian river
Authors: González Martín A. , Angón Elena , Rodríguez Jorge , Moya Ángel , García Antón , Peña Francisco
Published: August 2017

This study was conducted to determine the composition of cultured and wild Cichlasoma festae in Ecuador. The mean slaughter yield and dress-out were similar for cultured and wild specimens and the average fillet fat content for cultured fish was significantly higher compared to the wild fish. The pH, fillet color, drip loss and coked loss were similar between populations. Significant differences were found in protein, lipid and ash content in both studied populations. This study showed that saturated fatty acid (SFA) was higher than sum of monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) in both populations. Palmitic, oleic and linoleic acids had the maximum percentage of SFA, MUFA and PUFA respectively. In cultured and wild fish was also found to differ in the PUFA/SFA, docosahexaenoic acid/eicosapentaenoic acid, n-3/n-6 ratios and atherogenicity and thrombogenicity indices. Minerals included Ca, P, K, Mg, Zn, Fe, Cu and Mn. There were significant differences in the first six ones. The production system (cultured or wild) influences significantly most of the analyzed characteristics of carcass and flesh of C. festae. These results provide valued nutritional information of native species to produce sources of food with low-fat and high-protein, and safety food for the consumers in Ecuadorian country.
A bio-economic model to improve profitability in a large national beef cattle population
Authors: López-Paredes Javier , Jiménez-Montero Jose-Antonio , Pérez-Cabal Maria-Angeles , González-Recio Oscar , Alenda Rafael
Published: August 2017

A bio-economic model was developed for estimating economic values for use in improving profitability in a large national beef cattle population from birth to slaughter. Results were divided into fattening costs, production costs and income. Economic values were derived for 17 traits for two regions, mature weight (-0.43 € and -0.38 €/+1 kg of live weight), age at first calving (-0.13 € and -0.11 €/+1d), calving interval (-1.06 € and -1.02 €/+1d), age at last calving (0.03 € and 0.03 €/+1d), mortality 0-48 h (-5.86 € and -5.63 €/1% calves per cow and year), pre-weaning mortality (-5.96 € and -5.73 €/+1% calves per cow and year), fattening mortality (-8.23 € and -7.88 €/+1% calves per cow and year), adult mortality (-8.92 € and -7.34 €/+1% adult cows per cow and year), pre-weaning average daily gain (2.56 € and 2.84 €/+10g/d), fattening young animals average daily gain (2.65 € and 3.00 €/+10g/d), culled cow in fattening average daily gain (0.25 € and 0.16 €/+10g/d), culled cow dressing carcass percentage (3.09 € and 2.42 €/+1%), culled cow price (4.59 € and 3.59 €/+0.06 €/kg), carcass conformation score (16.39 € and 15.3 €/+1 SEUROP class), dressing carcass rate of calf (18.22 € and 18.23 €/+1%), carcass growth (9.00 € and 10.09 €/+10g of carcass weight/d) and age at slaughter (0.27 € and 0.44 €/+1d). Two sample herds were used to show the economic impact of calving interval and age at first calving shortening in the profit per slaughtered young animal, which was 178 € and 111 € for Herds A and B, respectively. The economic values of functional traits were reduced and production traits were enhanced when fertility traits were improved. The model could be applied in a Spanish national program.
Vantagens de citação do acesso aberto em periódicos selecionados da Ciência da Informação: uma análise ampliada aos indicadores altmétricos
Authors: Cintra Paulo Roberto , Furnival Ariadne Chloe , Milanez Douglas Henrique
Published: August 2017

Introdução: O acesso aberto diz respeito à literatura científica disponibilizada a qualquer usuário sem custos e livre das restrições de copyright e de licenciamento para seu reuso. Espera-se, de acordo com a hipótese do Open Access Citation Advantage, um aumento no número total de citações recebidas pelo artigos disponibilizados em acesso aberto com relação àqueles em acesso restrito.Objetivo: Analisar as possíveis vantagens de citações e menções na web social que o acesso aberto pode oferecer à área da Ciência da Informação.Metodologia: Foram analisados indicadores altmétricos e bibliométricos de citação de dois periódicos científicos: Journal of the American Society for Information Science e Scientometrics. A coleta dos dados foi realizada na Web of Science, Google Acadêmico, Altmetric.com e Mendeley.Resultados: Os resultados indicaram que o acesso aberto oferece vantagem quanto ao número de citações e de menções na web social recebidas pelos artigos em ambos as revistas. Verificou-se também que essa vantagem se mantém ao longo dos anos.Conclusões: A investigação confirma a hipótese do Open Access Citation Advantage para os periódicos selecionados da área da Ciência da Informação e demonstra que essa vantagem se estende aos dados altmétricos.
O perfil do gestor da informação: um estudo a partir dos egressos do curso de Gestão da Informação da UFPE
Authors: Cruz Tatyane Lucia , Silva Fábio Mascarenhas e , Bufrem Leilah Santiago , Sobral Natanael Vitor
Published: August 2017

Introdução: Com as recentes transformações sociais e econômicas surgiram novas possibilidades de atuação dos profissionais da informação. Neste contexto, insere-se o Gestor da informação, que pode contribuir na busca de soluções para os principais desafios relativos à coleta, processamento e uso da informação.Objetivo: Estudar as relações entre a formação acadêmica do Gestor da informação, egresso da UFPE, e a sua atuação profissional.Metodologia: a) revisão bibliográfica; b) mapeamento dos egressos; c) elaboração do questionário; d) disponibilização do questionário; e) tabulação e formatação dos dados; f) análise dos dados.Resultados: 54 dos 71 egressos responderam o questionário (76%), percentual considerado satisfatório. Destaca como resultados: 85% dos egressos estão desenvolvendo atividades profissionais; 56% dos ocupados estão atuando em atividades relacionadas à área de Gestão da Informação; os segmentos de atuação profissional são diversos, com destaque para o setor de serviços (34%). Na pirâmide organizacional, constatou-se que o nível de atuação mais representativo é o operacional (43%). No quesito disciplinas, chamou a atenção que os gestores têm uma maior necessidade de empregar os conhecimentos ligados a Tecnologia da Informação.Conclusões: Destaca-se a importância do Gestor da informação na atualidade, enfatizando a necessidade de aperfeiçoamento dessa profissão recente em relação às demandas da sociedade.
Aspectos da economia da informação: arquétipo conceitual econômico e social
Authors: Corrêa Fábio , Ribeiro Jurema Suely de Araújo Nery , Pinheiro Marta Macedo Kerr
Published: August 2017

Introdução: As empresas passaram por significativas mudanças advindas de paradigmas evolutivos amparados por aspectos tecnológicos e informacionais, que provocaram transformações diversas tornando o ambiente, interno e externo, das organizações complexo, devido ao intricado rompimento de padrões na evolução da sociedade, no qual a informação, competição e tecnologia possuem atuação determinante.Objetivo: Este estudo objetivou promover uma reflexão acerca dos aspectos da economia da informação que determinam esta nova sociedade, norteando-se pela problemática: Quais aspectos subvertedores fundamentam a economia da informação?Metodologia: Trata-se de uma pesquisa exploratória, por buscar uma ótica dilatada da economia da informação a fim de proporcionar compreensão e reflexão sobre seus aspectos subversores, e descritiva por objetivar elucidar, pela análise e interpretação dos fatos, as dimensões da economia da informação.Resultados: Com resultado foi proposto um arquétipo conceitual dos aspectos subvertedores da economia da informação, representados pelas dimensões produção, pessoas, finanças, organização, ciência e mercado.Conclusão: Conclui-se que este estudo tende a contribuir para a compreensão e reflexão dos aspectos relacionados a economia da informação, por meio da comparação com as eras da sociedade, oferecendo assim uma visão ampla desta economia.
Recomendações para certificação ou medição de confiabilidade de Repositórios Arquivísticos Digitas com ênfase no acesso à informação
Authors: Gonçalez Paula Regina Ventura Amorim
Published: August 2017

Introdução:Considerando as diretrizes da Norma ISO 16363:2012 (Space data and information transfer systems -- Audit and certification of trustworthy digital repositories) e o texto da Resolução 39 do CONARQ para certificação de Repositório Arquivístico Digital Confiável (RDC-Arq), verificar quais as recomendações técnicas devem ser utilizadas como base para que um repositório arquivístico digital seja considerado confiável.Objetivo: Identificar requisitos para a criação de Repositórios Arquivísticos Digitais Confiáveis com ênfase no acesso à Informação a partir da Norma ISO 16363:2012 e da Resolução 39 do CONARQ Metodologia: Para o desenvolvimento do estudo, a metodologia consistiu em uma investigação teórica de nível exploratória, descritivo e documental visto que, está fundamentada na Norma ISO 16363:2012 e na Resolução 39 do CONARQ. Pela perspectiva da abordagem do problema o estudo é qualiquantitativo, pois, os dados foram coletados, tabulados, e analisados a partir da interpretação de seus conteúdos.Resultados: Apresenta-se um conjunto de Recomendações de Checklist para medição e/ou certificação de confiabilidade para RDC-Arq com um recorte focado na identificação de requisitos com ênfase no acesso à informação.Conclusões: O direito à informação bem como o acesso à informação confiável é uma premissa para Repositórios Arquivísticos Digitais, assim, o conjunto de recomendações é dirigido a arquivistas que atuam em Repositórios Digitais e desejam verificar os requisitos necessários para avaliação de confiabilidade do Repositório Digital ou ainda guiar o profissional da informação na coleta de requisitos para certificação de confiabilidade do repositório.
An Analysis of Factors Associated with 25-Hydroxyvitamin D Levels in White and Non-White Canadians
Authors: Brooks Stephen P J , Greene-Finestone Linda , Whiting Susan , Fioletov Vitali E , Laffey Patrick , Petronella Nicholas
Published: August 2017

Vitamin D status was assessed in 19–79 year old whites (8351 participants of European ancestry) and non-whites (1840 participants encompassing allother ancestries) from cycles 1 to 3 (years 2007–2013) of the Canadian Health Measures Survey. Status was assessed using the U.S. Institute of Medicine (IOM) 25-hydroxyvitamin D [25(OH)D] cut point values of 30 and 40 nmol/L. Overall, median 25(OH)D concentrations were significantly higher in whites [58.9 (28.6, 100.1) nmol/L; 5th and 95th percentile] compared with non-whites [43.5 (19.0, 83.2); P < 0.001]. Values were higher in females [58.5 (27.5, 101.3) nmol/L] when compared with males[53.5 (24.2, 92.7) nmol/L] and increased with age. Non-whites were more likely to have 25(OH)D values below IOM established cut points for optimum bone health with 20.1 (16.0, 24.2) and 42.2% (36.8, 47.7) of non-whites having serum 25(OH)D concentrations <30 and <40 nmol/L, respectively. The correspondingvalues for whites were 5.9 (4.6, 7.2) and 16.1% (14.0, 18.3). Values were lower during the first quarterwhen compared with the third quarter. Supplement intake was an important factor in determining 25(OH)D levels, but it did not alone account for the difference in status. Equivalent increases in 25(OH)D levelswere observed in whites and non-whites during the summer months, suggesting there was no functional difference in sun exposure response. It is apparent thata complex interaction of factors affect 25(OH)D values in free-living Canadians.
Avaliação institucional: socialização do estudo no município de Escada/PE
Authors: Silva Júnior Aldemir Lima da , Monte Valderês Conceição do
Published: August 2017

Este estudo se relaciona com o tema avaliação institucional, em especial com as ações desenvolvidas pelo gestor da Secretaria Municipal de Educação e pelos gestores escolares do município da Escada/PE frente aos resultados do Saepe 2014. Nossa hipótese é que a rede municipal de educação de Escada/PE, diante dos resultados do Saepe 2014, parece não promover ações sistemáticas e contínuas nas escolas. A abordagem é qualitativa, tipo descritiva e foi realizada na Secretaria Municipal de Educação e em duas escolas públicas. Os sujeitos foram dois gestores escolares, a gestora municipal e uma técnica educacional. Os instrumentos de coleta de dados foram análise documental e entrevista semi-estruturada. Os resultados apontaram que os gestores não têm ações frente ao resultado do Saepe, a maioria dos sujeitos não responde o que é avaliação institucional e desconhecem a estrutura organizacional da Secretaria Municipal de Educação.Palavras-chave: avaliação institucional, Saepe, gestão educacional.
A escolha do livro didático: um instrumento de apoio ao corpo docente do ensino fundamental
Authors: Vilarinho Lúcia Regina Goulart , Pimentel Sandra Regina Gonçalves
Published: August 2017

O objetivo deste estudo foi construir e validar um instrumento para ser utilizado por docentes dos anos iniciais do ensino fundamental em suas análises de livros didáticos. Tomou-se como referência posicionamentos do corpo docente do Colégio Pedro II, situados como especialistas dessa avaliação. Os subsídios das categorias de avaliação e seus indicadores foram retirados do projeto político-pedagógico do colégio e da literatura específica. Na análise das respostas dadas no questionário, que avaliou o instrumento, verificou-se uma ampla aceitação do instrumento como apoio à tarefa de escolher o livro didático.Palavras-chave: avaliação, livro didático, instrumento de avaliação, ensino fundamental.
Feasibility of CO2-EOR in Shale-Oil Reservoirs: Numerical Simulation Study and Pilot Tests
Authors: Alfarge Dheiaa , Wei Mingzhen , Bai Baojun
Published: August 2017

Shale oil reservoirs such as Bakken, Niobrara, and Eagle Ford have become the main target for oil and gas investors as conventional formations started to be depleted and diminished in number. These unconventional plays have a huge oil potential; however, the predicted primary oil recovery is still low as an average of 7.5 %. Injecting carbon dioxide (CO2) to enhance oil recovery in these poor-quality formations is still a debatable issue among investigators. In this study, three steps of research have been integrated to investigate the parameters which control the success of CO2 huff-n-puff process in the field scale of shale oil reservoirs. Firstly, a numerical simulation study was conducted to upscale the reported experimental studies outcomes to the field conditions. The second step was to validate these numerical models with the field data from some of CO2-EOR pilots which were performed in Bakken formation, in North Dakota and Montana regions. Finally, statistical methods for Design of Experiments (DOE) have been used to rank the most important parameters affecting CO2-EOR performance in these unconventional reservoirs.

The Design of Experiments approved that the intensity of natural fractures (the number of natural fractures per length unit in each direction, I-direction, J direction, and K direction) and the conductivity of oil pathways (the average conductivity for the entire oil molecules path, from its storage (matrix) to the wellbore) are the two main factors controlling CO2-EOR success in shale oil reservoirs. However, the fracture intensity has a positive effect on CO2-EOR while the later has a negative effect. Furthermore, this study found that the porosity and the permeability of natural fractures in shale reservoirs are clearly changeable with the production time, which in turn, led to a clear gap between CO2 performances in the lab conditions versus to what happened in the field pilots. This work reported that the molecular diffusion mechanism is the key mechanism for CO2 to enhance oil recovery in shale oil reservoirs. However, the conditions of the candidate field and the production well criteria can enhance or downgrade this mechanism in the field scale. Accordingly, the operating parameters for managing CO2-EOR huff-n-puff process should be tuned according to the candidate reservoir and well conditions. Moreover, general guidelines have been provided from this work to perform successful CO2 projects in these complex plays.
Applicability of CO2-EOR in Shale-Oil Reservoirs Using Diagnostic Plots
Authors: Alfarge Dheiaa , Wei Mingzhen , Bai Baojun
Published: August 2017

Unconventional resources have played a significant role in changing oil industry plans recently. Shale formations in North America such as Bakken, Niobrara, and Eagle Ford have huge oil in place, 100–900 Billion barrels of recoverable oil in Bakken only. However, the predicted primary recovery is still below 10%. Therefore, seeking for techniques to enhance oil recovery in these complex plays is inevitable. In this paper, two engineering-reversed approaches have been integrated to investigate the feasibility of CO2 huff-n-puff process in shale oil reservoirs. Firstly, a numerical simulation study was conducted to upscale the reported experimental-studies outcomes to the field conditions. As a result, different forward diagnostic plots have been generated from different combinations of CO2 physical mechanisms with different shale-reservoirs conditions. Secondly, different backward diagnostic plots have been produced from the history match with CO2 performances in fields' pilots which were performed in Bakken formation of North Dakota and Montana. Finally, fitting the backward with the forward diagnostic plots was used to report and diagnose some findings regarding the injected-CO2 performance in field scale.

This study found that the porosity and permeability of natural fractures in shale reservoirs are significantly changed with production time, which in turn, led to a clear gap between CO2 performances in lab-conditions versus to what happened in field pilots. As a result, although experimental studies reported that CO2 molecular-diffusion mechanism has a significant impact on CO2 performance to extract oils from shale cores, pilot tests performances indicated a poor role for this mechanism in field conditions. Therefore, the bare upscaling process for the oil recovery improvement and the CO2-molecualr diffusion rate, which are obtained from CO2 injection in lab-cores, to the field scale via numerical simulations needs to be reconsidered. In addition, this study found that kinetics of oil recovery process in productive areas and CO2-diffusivity level are the keys to perform a successful CO2-EOR project. Furthermore, general guidelines have been produced from this work to perform successful CO2 projects in these complex plays. Finally, this paper provides a thorough idea about how CO2 performance is different in field scale of shale oil reservoirs as in lab-scale conditions.
A spiral attractor network drives rhythmic locomotion
Authors: Bruno Angela M , Frost William N , Humphries Mark D
Published: August 2017

The joint activity of neural populations is high dimensional and complex. One strategy for reaching a tractable understanding of circuit function is to seek the simplest dynamical system that can account for the population activity. By imaging Aplysia’s pedal ganglion during fictive locomotion, here we show that its population-wide activity arises from a low-dimensional spiral attractor. Evoking locomotion moved the population into a low-dimensional, periodic, decaying orbit - a spiral - in which it behaved as a true attractor, converging to the same orbit when evoked, and returning to that orbit after transient perturbation. We found the same attractor in every preparation, and could predict motor output directly from its orbit, yet individual neurons’ participation changed across consecutive locomotion bouts. From these results, we propose that only the low-dimensional dynamics for movement control, and not the high-dimensional population activity, are consistent within and between nervous systems.
Tissue-specific regulation of BMP signaling by Drosophila N-glycanase 1
Authors: Galeone Antonio , Han Seung Yeop , Huang Chengcheng , Hosomi Akira , Suzuki Tadashi , Jafar-Nejad Hamed
Published: August 2017

Mutations in the human N-glycanase 1 (NGLY1) cause a rare, multisystem congenital disorder with global developmental delay. However, the mechanisms by which NGLY1 and its homologs regulate embryonic development are not known. Here we show that Drosophila Pngl encodes an N-glycanase and exhibits a high degree of functional conservation with human NGLY1. Loss of Pngl results in developmental midgut defects reminiscent of midgut-specific loss of BMP signaling. Pngl mutant larvae also exhibit a severe midgut clearance defect, which cannot be fully explained by impaired BMP signaling. Genetic experiments indicate that Pngl is primarily required in the mesoderm during Drosophila development. Loss of Pngl results in a severe decrease in the level of Dpp homodimers and abolishes BMP autoregulation in the visceral mesoderm mediated by Dpp and Tkv homodimers. Thus, our studies uncover a novel mechanism for the tissue-specific regulation of an evolutionarily conserved signaling pathway by an N-glycanase enzyme.
Remote sensing techniques for determining landcover features: applications for a species at risk
Authors: Fauvelle Catherine , Diepstraten Rianne
Published: August 2017

Remote sensing techniques are becoming more advanced and commonplace in conservation biology, and are used to study spatial patterns of various taxa. The main objective of this study was to determine whether supervised classification of landcover types within Landsat imagery could be accurately used to find or locate islands on lakes that may have been overlooked during ground transects in central Saskatchewan. Additionally, we used telemetry data from collared female caribou to determine which islands were used and in which season(s), and to determine island char­acteristics that make caribou more likely to select them. We were able to successfully identify all islands within bodies of water relevant to collared caribou using a supervised classification method, which suggests that our methods were adequate. We also determined that none of the island characteristics significantly influenced caribou selection accord­ing to an occupancy model, however females tended to choose islands with a higher vegetation cover (NDVI) during the summer months and a proportionally lower snow cover during the winter months, likely as forage and predator avoidance strategies respectively. Finally, we suggest directions for future studies as well as implications for both wildlife managers and land-use planners in Saskatchewan, Canada.
North Atlantic Deep Water formation inhibits high Arctic contamination by continental perfluorooctane sulfonate discharges
Authors: Zhang Xianming , Zhang Yanxu , Dassuncao Clifton , Lohmann Rainer , Sunderland Elsie M.
Published: August 2017

Perfluorooctane sulfonate (PFOS) is an aliphatic fluorinated compound with eight carbon atoms that is extremely persistent in the environment and can adversely affect human and ecological health. The stability, low reactivity, and high water solubility of PFOS combined with the North American phaseout in production around the year 2000 make it a potentially useful new tracer for ocean circulation. Here we characterize processes affecting the lifetime and accumulation of PFOS in the North Atlantic Ocean and transport to sensitive Arctic regions by developing a 3‐D simulation within the MITgcm. The model captures variability in measurements across biogeographical provinces (R2 = 0.90, p = 0.01). In 2015, the North Atlantic PFOS reservoir was equivalent to 60% of cumulative inputs from the North American and European continents (1400 Mg). Cumulative inputs to the Arctic accounted for 30% of continental discharges, while the remaining 10% was transported to the tropical Atlantic and other regions. PFOS concentrations declined rapidly after 2002 in the surface mixed layer (half‐life: 1–2 years) but are still increasing below 1000 m depth. During peak production years (1980–2000), plumes of PFOS‐enriched seawater were transported to the sub‐Arctic in energetic surface ocean currents. However, Atlantic Meridional Overturning Circulation (AMOC) and deep ocean transport returned a substantial fraction of this northward transport (20%, 530 Mg) to southern latitudes and reduced cumulative inputs to the Arctic (730 Mg) by 70%. Weakened AMOC due to climate change is thus likely to increase the magnitude of persistent bioaccumulative pollutants entering the Arctic Ocean.
Seismically invisible fault zones: Laboratory insights into imaging faults in anisotropic rocks
Authors: Kelly C. M. , Faulkner D. R. , Rietbrock A.
Published: August 2017

Phyllosilicate‐rich rocks which commonly occur within fault zones cause seismic velocity anisotropy. However, anisotropy is not always taken into account in seismic imaging and the extent of the anisotropy is often unknown. Laboratory measurements of the velocity anisotropy of fault zone rocks and gouge from the Carboneras fault zone in SE Spain indicate 10–15% velocity anisotropy in the gouge and 35–50% anisotropy in the mica‐schist protolith. Greater differences in velocity are observed between the fast and slow directions in the mica‐schist rock than between the gouge and the slow direction of the rock. This implies that the orientation of the anisotropy with respect to the fault is key in imaging the fault seismically. For example, for fault‐parallel anisotropy, a significantly greater velocity contrast between fault gouge and rock will occur along the fault than across it, highlighting the importance of considering the foliation orientation in design of seismic experiments.
The characteristics and generation mechanism of small‐amplitude and large‐amplitude ESF irregularities observed by the C/NOFS satellite
Authors: Huang Chao‐Song
Published: August 2017

It is well understood that equatorial plasma bubbles are initiated in the bottomside F region and grow into the topside F region, producing equatorial spread F (ESF) irregularities in both bottomside and topside F regions. However, it is not known whether small‐amplitude and large‐amplitude irregularities have the same occurrence pattern and how the generation of small‐amplitude and large‐amplitude irregularities is related to the postsunset vertical plasma drift and potential seeding processes. In this study, we use ion density and velocity data measured by the Communications/Navigation Outage Forecasting System satellite during May 2008 to July 2014 to derive the longitude‐month distributions of the occurrence probability of ESF irregularities at different amplitudes. It is found that the occurrence probability of large‐amplitude irregularities is well correlated with the postsunset vertical plasma drift and that small‐amplitude irregularities do not show a clear pattern at low solar activity but is anticorrelated with that of large‐amplitude irregularities at moderate solar activity. That is, the months and longitudes with high occurrence probability of large‐amplitude irregularities are exactly those with low occurrence probability of small‐amplitude irregularities, and vice versa. ESF irregularities are mostly limited below 500 km during low solar activity in 2008–2010, but large‐amplitude irregularities can reach 700–800 km in altitude during moderate solar activity in 2011–2014. The generation of large‐amplitude ESF irregularities is controlled by the postsunset vertical plasma drift at both low and moderate solar activities. In contrast, small‐amplitude ESF irregularities at moderate solar activity occur more frequently in the areas where the postsunset vertical plasma drift is small.
The dependence of magnetospheric plasma mass loading on geomagnetic activity using Cluster
Authors: Sandhu J. K. , Yeoman T. K. , Rae I. J. , Fear R. C. , Dandouras I.
Published: August 2017

Understanding changes in the magnetospheric mass density during disturbed geomagnetic conditions provides valuable insight into the dynamics and structure of the environment. The mass density plays a significant role in a variety of magnetospheric processes, such as wave propagation, magnetic reconnection rates, and radiation belt dynamics. In this study, the spatial variations of total plasma mass density are explored through the analysis of Cluster observations. Data from the WHISPER (Waves of High frequency and Sounder for Probing of Electron density by Relaxation) and CODIF (ion Composition and Distribution Function analyzer) instruments, on board the four Cluster spacecraft for a time interval spanning 2001–2012, are used to determine empirical models describing the distribution of the total plasma mass density along closed geomagnetic field lines. The region considered covers field lines within 5.9≤L< 9.5, corresponding to the outer plasmasphere, plasmatrough, and near‐Earth plasma sheet. This study extends previous work to examine and quantify spatial variations in the electron density, average ion mass, and total plasma mass density withDstindex. The results indicate that during periods of enhanced ring current strength, electron density is observed to decrease and average ion mass is observed to increase, compared with quiet geomagnetic conditions. The combination of these variations shows that although heavy ion concentration is enhanced, the decrease in plasma number density results in a general decrease in total plasma mass density during disturbed geomagnetic conditions. The observed decrease in mass density is in contrast to prevailing understanding and, due to the dependence of the Alfvén speed on mass density, has important implications for a range of plasma processes during storm time conditions (e.g., propagation of wave modes).
Detailed characteristics of radiation belt electrons revealed by CSSWE/REPTile measurements: Geomagnetic activity response and precipitation observation
Authors: Zhang K. , Li X. , Schiller Q. , Gerhardt D. , Zhao H. , Millan R.
Published: August 2017

Earth's outer radiation belt electrons are highly dynamic. We study the detailed characteristics of relativistic electrons in the outer belt using measurements from the Colorado Student Space Weather Experiment (CSSWE) mission, a low Earth orbit (LEO) CubeSat, which traverses the radiation belt four times in one orbit (~1.5 h) and has the advantage of measuring the dynamic activities of the electrons including their rapid precipitation. We focus on the measured electron response to geomagnetic activity for different energies to show that there are abundant sub‐MeV electrons in the inner belt and slot region. These electrons are further enhanced during active times, while there is a lack of >1.63 MeV electrons in these regions. We also show that the variation of measured electron flux at LEO is strongly dependent on the local magnetic field strength, which is far from a dipole approximation. Moreover, a specific precipitation band, which happened on 19 January 2013, is investigated based on the conjunctive measurement of CSSWE, the Balloon Array for Radiation belt Relativistic Electron Losses, and one of the Polar Operational Environmental Satellites. In this precipitation band event, the net loss of the 0.58–1.63 MeV electrons (L = 3.5–6) is estimated to account for 6.8% of the total electron content.
Revisiting the structure of low‐Mach number, low‐beta, quasi‐perpendicular shocks
Authors: Wilson III L. B. , Koval A. , Szabo A. , Stevens M. L. , Kasper J. C. , Cattell C. A. , Krasnoselskikh V. V.
Published: August 2017

A study of the structure of 145 low‐Mach number (M≤3), low‐beta (β≤1), quasi‐perpendicular interplanetary collisionless shock waves observed by the Wind spacecraft has provided strong evidence that these shocks have large‐amplitude whistler precursors. The common occurrence and large amplitudes of the precursors raise doubts about the standard assumption that such shocks can be classified as laminar structures. This directly contradicts standard models. In 113 of the 145 shocks (∼78%), we observe clear evidence of magnetosonic‐whistler precursor fluctuations with frequencies ∼0.1–7 Hz. We find no dependence on the upstream plasma beta, or any other shock parameter, for the presence or absence of precursors. The majority (∼66%) of the precursors propagate at ≤45° with respect to the upstream average magnetic field and most (∼87%) propagate ≥30° from the shock normal vector. Further, most (∼79%) of the waves propagate at least 20° from the coplanarity plane. The peak‐to‐peak wave amplitudes (δBpk‐pk) are large with a range of maximum values for the 113 precursors of ∼0.4–13 nT with an average of ∼2 nT. When we normalize the wave amplitudes to the upstream averaged magnetic field and the shock ramp amplitude, we find average values of ∼40% and ∼220%, respectively.
A fluid‐rich layer along the Nankai trough megathrust fault off the Kii Peninsula inferred from receiver function inversion
Authors: Akuhara Takeshi , Mochizuki Kimihiro , Kawakatsu Hitoshi , Takeuchi Nozomu
Published: August 2017

Investigation of fluid distribution along megathrust faults is an important issue, since the fluid affects frictional properties and thus slip behavior on faults. Scattered teleseismic phases, or receiver functions (RFs), have made significant contributions to understanding the fluid content of subducting plates beneath the onshore regions but have been rarely applied in offshore settings. In this study, we conducted receiver function inversion analysis to investigate detailed seismic properties near the megathrust fault using ocean bottom seismometers deployed off the Kii Peninsula, southwest Japan. RFs were calculated at high frequencies (up to 4 Hz), removing the effect of water reverberations from vertical component records. Our inversion was performed in two steps: first, we modeled sediment layer by a simple stacking method and then solved for deeper structure by a waveform inversion. The results indicate the presence of a thin low‐velocity zone (LVZ) of a thickness of 0.2–1.2 km with a S wave velocity of 0.7–2.4 km/s along the plate interface. We interpret this LVZ as thin fluid‐rich sediment layer between the overriding and subducting plates that acts as a pathway of fluid migration.
Estimating network effect in geocenter motion: Theory
Authors: Zannat Umma Jamila , Tregoning Paul
Published: August 2017

Geophysical models and their interpretations of several processes of interest, such as sea level rise, postseismic relaxation, and glacial isostatic adjustment, are intertwined with the need to realize the International Terrestrial Reference Frame. However, this realization needs to take into account the geocenter motion, that is, the motion of the center of figure of the Earth surface, due to, for example, deformation of the surface by earthquakes or hydrological loading effects. Usually, there is also a discrepancy, known as the network effect, between the theoretically convenient center of figure and the physically accessible center of network frames, because of unavoidable factors such as uneven station distribution, lack of stations in the oceans, disparity in the coverage between the two hemispheres, and the existence of tectonically deforming zones. Here we develop a method to estimate the magnitude of the network effect, that is, the error introduced by the incomplete sampling of the Earth surface, in measuring the geocenter motion, for a network of space geodetic stations of a fixed size N. For this purpose, we use, as our proposed estimate, the standard deviations of the changes in Helmert parameters measured by a random network of the same size N. We show that our estimate scales as
and give an explicit formula for it in terms of the vector spherical harmonics expansion of the displacement field. In a complementary paper we apply this formalism to coseismic displacements and elastic deformations due to surface water movements.
Estimating network effect in geocenter motion: Applications
Authors: Zannat Umma Jamila , Tregoning Paul
Published: August 2017

The network effect is the error associated with the subsampling of the Earth surface by space geodetic networks. It is an obstacle toward the precise measurement of geocenter motion, that is, the relative motion between the center of mass of the Earth system and the center of figure of the Earth surface. In a complementary paper, we proposed a theoretical approach to estimate the magnitude of this effect from the displacement fields predicted by geophysical models. Here we evaluate the effectiveness of our estimate for two illustrative physical processes: coseismic displacements inducing instantaneous changes in the Helmert parameters and elastic deformation due to surface water movements causing secular drifts in those parameters. For the first, we consider simplified models of the 2004 Sumatra‐Andaman and the 2011 Tōhoku‐Oki earthquakes, and for the second, we use the observations of the Gravity Recovery and Climate Experiment, complemented by an ocean model. In both case studies, it is found that the magnitude of the network effect, even for a large global network, is often as large as the magnitude of the changes in the Helmert parameters themselves. However, we also show that our proposed modification to the definition of the center of network frame to include weights proportional to the area of the Earth surface that the stations represent can significantly reduce the network effect in most cases.