bluuebunny/crossref_metadata_2025 huggingface dataset:
Un nuevo enfoque para optimizar dosificaciones de hormigón autocompactante
Authors: Garcia-Taengua Emilio , Linden Benjamin
Published: March 2018

Todo procedimiento para diseñar hormigones autocompactantes comprende dos etapas: la aplicación de un método de dosificación, y el ajuste de la mezcla mediante amasadas de prueba. Ambas se centran en el comportamiento del hormigón en estado fresco, buscándose maximizar tres propiedades fundamentales: fluidez, capacidad de llenado, y estabilidad. Para su evaluación y control se pueden monitorizar multitud de parámetros obtenidos mediante distintos ensayos, pero raramente se recurre a más de dos o tres ensayos, que además varían de un caso a otro. Además, estos muestran un importante grado de correlación entre sí, y por tanto existe siempre cierto solape entre la información obtenida mediante cualesquiera dos ensayos. Este estudio propone formular matemáticamente el comportamiento en fresco del hormigón autocompactante como un fenómeno multivariado. Aunque sus tres propiedades fundamentales no son directamente medibles de forma independiente, se pueden obtener mediante transformación lineal a partir de las métricas que ofrece cada tipología de ensayo. Este nuevo enfoque posibilita una optimización más robusta de los hormigones autocompactantes. Con esta finalidad, se ha llevado a cabo un metanálisis de cerca de trescientas dosificaciones recogidas de distintas fuentes, abarcando: las propiedades de los materiales utilizados y sus cantidades relativas; los resultados de los ensayos de escurrimiento, embudo en V, anillo en J, caja en L, e índice visual de segregación; y la resistencia media a compresión simple. Se han estudiado las relaciones de codependencia entre los distintos parámetros medibles, y cómo estas relaciones se ven afectadas por cambios en la dosificación. Para ello se han aplicado las técnicas de reducción de información utilizadas en minería de datos y se han desarrollado modelos semiempíricos mediante regresión lineal múltiple. Las ecuaciones obtenidas se han utilizado para formular explícitamente el problema de optimización multiobjetivo para obtener altos niveles de autocompactabilidad a la vez que se minimiza el riesgo de segregación. Dicho problema se ha resuelto de forma gráfica en una serie de escenarios hipotéticos para ilustrar la aplicación de la nueva metodología desarrollada, que permite reducir el número de amasadas de prueba necesarias y por tanto conlleva un ahorro significativo en tiempo y recursos.DOI: http://dx.doi.org/10.4995/HAC2018.2018.5958
Estudo do volume de pasta em diferentes composições de agregados para concreto autoadensável
Authors: Gomes Paulo César , Melo Cassia , Monteiro Roberto
Published: March 2018

O artigo estuda a variação do volume de pasta nos concretos autoadensáveis (CAA) obtidos no estudo prévio de Monteiro et al. (2015), apresentado no HAC2015, verificando o atendimento às propriedades de autoadensabilidade. A garantia destas propriedades depende da composição dos agregados. Estudos têm obtido composições ótimas de agregados aplicando modelos de empacotamento de partículas, menor porosidade. Porém, a garantia da autoadensabilidade pode elevar o volume de pasta. Esta garante a mobilidade e é influenciada pela composição dos agregados. Neste contexto, o estudo utilizando as diferentes composições de agregados propostas por Monteiro et al. (2015), obtidas pelo critério do menor teor de vazios, avalia estas composições buscando-se um menor volume de pasta que atendesse a autoadensabilidade. As composições de agregados de cada combinação (binária, ternária e quaternária) foram avaliadas através do módulo de distribuição (q) do modelo de empacotamento de Alfred. O volume de pasta de 40%, inicialmente utilizado nos CAA por Monteiro et al. (2015), foi reduzido para 38% e 35%, nos CAAs que atenderam os parâmetros de autoadensabilidade. A composição da pasta manteve-se fixa. A autoadensabilidade foi avaliada nos ensaios de espalhamento (slump flow), Funil V e caixa L. Os resultados mostraram que as composições com maior volume de pasta (40%) nem sempre atenderam aos valores de q indicados na literatura para CAA. As composições selecionadas de cada combinação (binária, ternária e quaternária) com 38% de pasta atenderam a autoadensabilidade. Já as mesmas composições com 35% de pasta apenas a quaternária atendeu.DOI: http://dx.doi.org/10.4995/HAC2018.2018.6045
Diseño de mezclas de hormigones autocompactantes con alto contenido de adiciones minerales y áridos de diferentes naturaleza para desempeño en ambientes altamente agresivos
Authors: Puentes Mojica Javier , Calvo Jose Luis , Alonso Alonso M. Cruz
Published: March 2018

The advances in the use of self-compacting concrete (SCC) increases its consumption in construction materials. The SCC has ease of placement and refinement of the microstructure due to the increase of the volume of paste and fines thus improving the resistance to the penetration of aggressive agents. Therefore, its use is not limited to usual scenarios but focusing also to environments with severe operating conditions as is the case of energy transport infrastructures, often located in remote and extreme places. These conditions of application and location restrict the type of materials to be used in the design of concrete: type of aggregates, type of cement, use of supplementary cementitious materials (SCM), etc. The development of SCC also must imply an increase in the sustainability of the construction process by promoting the use of binders with mineral additions and limestone filler , in order to reduce the total cement content (due to the reduction of CO2 emissions associated to cement production) thus decreasing their environmental footprint. However, the incorporation of SCM implies the need to ensure compatibility with the chemical additives, superplasticizers, while maintaining the fresh state properties. Another relevant factor is the type and characteristics of aggregates that significantly affect the workability of concrete. The aggregates provide an improvement in performance in a hardened state, but in some cases they modify the consistency losing the self-compactibility of the concrete.The aim of this study is to evaluate the influence of the composition of the mixture components on the fresh and hardened properties of the SCC: 1) Interaction of the additives with cements with high mineral addition content (50%) of slag and fly ash; 2) the effect of the use of mixtures of aggregates with different origin, shape and composition that provide the special properties required concentrated solar power plants. Mixtures of aggregates, limestone, basalt and crushed Clinker have been considered along with additives that promote flowability, water reducers and density enhancement. Robust SCCs can be developed with high stability suitable for CSP application.DOI: http://dx.doi.org/10.4995/HAC2018.2018.6324
Influencia de las variaciones en los materiales sobre la reología de hormigones autocompactantes reciclados
Authors: González Fonteboa Belen , González Taboada Iris , Martínez Abella Fernando , Rojo López Gemma
Published: March 2018

Este trabajo se centra en el análisis de la influencia de las variaciones de materiales en el comportamiento reológico de los hormigones autocompactantes fabricados con árido grueso reciclado. Se diseña un hormigón autocompactante patrón y tres reciclados con porcentajes de sustitución del 20%, 50% y 100% en volumen. Asimismo, en cada una de estas mezclas se efectúan variaciones en el contenido de agua, superplastificante y cemento para simular errores que se producen en las plantas de fabricación. Estas variaciones son de ± 3% en el agua, ± 5% en el superplastificante y ± 3% en el cemento. Todos los hormigones se estudian en estado fresco mediante ensayos reológicos: stress growth test y flow curve test.Con la utilización de reogramas de comportamiento, se evalúan los cambios reológicos que un incremento o decremento de agua, superplastificante o cemento pueden ocasionar. Los resultados permiten estudiar a qué variación de material es más sensible un hormigón autocompactante reciclado (HACR) y qué porcentajes de árido reciclado sería más recomendable utilizar para obtener un hormigón robusto.DOI: http://dx.doi.org/10.4995/HAC2018.2018.6361
UHPFRC for the cast-in place reinforcement of offshore maritime signalization structures
Authors: Denarié Emmanuel
Published: March 2018

Offshore lighthouses are a remarkable historical heritage often over 100 years old. The management of their aging is a challenge. The extremely low permeability of Ultra-High-Performance Fiber Reinforced Concretes (UHPFRC), combined with their outstanding mechanical properties (robust tensile Strain Hardening (SH) for specific mixes) are particularly suitable for the reinforcement of this type of structures and more generally offshore maritime signalization structures. These structures under the influence of tides and weather, exposed to a very aggressive environment, have very limited access. As for existing bridges, SH-UHPFRC provide in this case a robust, effective, and very durable reinforcement solution, making it possible to simplify and reduce the duration of interventions. In this context, an existing turret at sea, on the south coast of Brittany, was reinforced by the application of a 60 mm UHPFRC hull, cast in place by helicopter in a formwork around the existing masonry structure. This application paves the way for the reinforcement with the same materials of lighthouses at sea exposed to extreme weathering conditions, such as "La Jument" nearby the island of Ushant (Brittany, France).DOI: http://dx.doi.org/10.4995/HAC2018.2018.8261
The digital labor of queering feminist Web TV
Authors: Elerding Carolyn
Published: March 2018

Episodes in two queer and feminist Web TV programs, Orange Is the New Black and Her Story, feature ambivalent representations of labor and social reproduction. These narratives suggest implications for digital economy, particularly its algorithms and its connection with the disruption of conventional social and economic categories. This comparative analysis mobilizes theories from feminist media studies and cultural studies to present the viewing of queer and feminist Web TV as forming networks of care and, potentially, resistance in addition to producing economic value.
Impact of Accounting Data on Stock Prices: The Case of Vietnam
Authors: Viet Ha Hoang Thi , Hung Dang Ngoc , Dung Tran Manh
Published: March 2018

This research is conducted for evaluating the impact of accounting numbers on stock prices of listed firms on Vietnam Stock Exchange. Data were collected from 416 listed firms for the period from 2012 to 2016. By using models of OLS, FEM, REM and GLS for evaluating the relationship between earnings per share (EPS), book value of stock (BV) and stock prices, the results show that EPS, BV have positive relationships with stock prices with the level of 48.13% basing on the model of Ohlson (1995) and on the model of Ohlson adjusted to Aboody et al. (2002). Based on the findings, some implications for investors and stakeholders have been given in the context of Vietnam.
Los modelos basados en agentes y la ciencia de las consecuencias inintencionadas de la acción
Authors: Linares Francisco
Published: March 2018

El propósito de este artículo es defender la tesis de que los modelos basados en agentes (ABMs) permiten abordar solventemente el problema del vínculo micro-macro en las ciencias sociales. El argumento se desarrolla en cuatro etapas: en primer lugar, se sostiene que las CC.SS. requieren una teoría de la acción construida sobre un mecanismo explicativo concreto, denominado «principio de acción». Seguidamente se expone cómo, en el ámbito de la sociología, el vínculo micro-macro se ha teorizado, en buena medida, siguiendo un modelo que puede denominarse «transición interaccionista». En tercer lugar se muestra que los ABMs se ajustan a las propiedades del modelo de transición interaccionista, a la vez que le aportan mecanismos explicativos específicos. Finalmente, el argumento se ilustra mediante el caso del análisis de la reproducción social de las desigualdades educativas.
Cambio y continuidad en tres generaciones de mujeres un análisis longitudinal cualitativo de las formas de trabajo
Authors: Martín-Palomo M. Teresa , Tobío Soler Constanza
Published: March 2018

Este artículo indaga en la relación entre la transmisión de pautas laborales a través de generaciones de mujeres y la generalización del empleo femenino. Se trata de ver cómo un fenómeno macro, la incorporación de las mujeres al mercado laboral, opera a escala micro y en qué medida hay continuidades entre abuelas, madres e hijas que retrasan o adelantan la tendencia a la inserción laboral de todas las personas adultas. En este sentido podría hablarse de path dependency,concepto que puede ser de utilidad para comprender la transmisión entre generaciones de mujeres de la relación con la actividad. Utiliza metodología cualitativa longitudinal a partir de los relatos de diez tríadas femeninas que representan diferentes combinaciones de trabajo monetarizado y no monetarizado caracterizadas como tradicionales, de transición, regresivas y modernas.
Effectiveness of Poverty Reduction Program with Value Added Creation in Agribusiness Sector and Formulation of Strategic Plan and Policies
Authors: Yustini Tien
Published: March 2018

The purpose of this study is to formulate value creation models for agribusiness development to address rural poverty issues and analyze and design a Strategic (policy) model that should be developed for poverty alleviation in South Sumatra.The object of this study was conducted in Palembang City and Ogan Ilir Regency which identified the poor still relatively big. To measure the effectiveness of poverty alleviation programs that have been done by the government, conducted descriptive qualitative and quantitative analysis. Qualitative analysis is done by describing poverty alleviation programs that have been done, continued and will be done by the government together with other stakeholders. Further analyzed the problems or obstacles encountered in the implementation, formulation and develop a model of community empowerment that is considered effective enough to overcome poverty. The effectiveness analysis is calculated by comparing the planned targets with the results achieved.From the model formulated and built it is expected to obtain strategies and policies that can be taken by the government to overcome the problems of poverty both in the city and in the countryside.
Potential of Spring Barley, Oat and Triticale Intercrops with Field Peas for Forage Production, Nutrition Quality and Beef Cattle Diet
Authors: Gill Kabal S. , Omokanye Akim T.
Published: March 2018

Spring barley (Hordeum vulgare L.), oat (Avena sativa L.) and triticale (x Triticosecale Wittmack) monocrops and their intercrops with two forage varieties (40-10 and Tucker) and one seed variety (Cooper) peas (Pisum sativum L.) were evaluated for forage production, nutrition quality and suitability in the beef cattle diet. Pea + cereal intercrops were compared to respective cereal monocrops in 2009, 2010 and 2011. Plant height of cereals tended to be reduced in intercrops compared to respective monocrops. Taller 40-10 forage type pea tended to cause lodging in 2009 and 2011, not observed with other pea varieties. Fresh forage of pea + cereal intercrops had higher moisture than respective cereal monocrops. Fourteen of the 18 intercrops had less dry matter yield (DMY) than respective cereal monocrops. Shorter Tucker pea had less negative impact on DMY than taller 40-10 pea. Treatments with barley had lower DMY than respective oat and triticale systems. Intercrops improved forage crude protein (CP) content over the respective monocrops, which was enough to overcome the DMY penalty and produce more CP yield than their monocrops. The forage Ca and Mg contents were improved by intercrops over their monocrops, and they were greater with 40-10 pea than other pea varieties and with barley than oat or triticale. The forage P content also tended to be higher in intercrops than corresponding monocrops, without a consistent effect of cereal type or pea variety. The forage K and S contents were not consistently influenced by the cereal types, pea varieties or intercrops. Forage Na content was greater from oat than respective barley and triticale treatments. The monocrops and intercrops had similar forage Cu content, and treatments with barley had more Cu than with oat or triticale. Forage Zn content tended to be intercrops > monocrops; and barley > triticale > oat. Treatments had no influence on the forage Fe and Mn contents. Levels of acid (ADF) and neutral (NDF) detergent fibres in the forage were similar for the corresponding intercrops and monocrops, and greater for oat than barley or triticale treatments. Some of the intercrops improved total digestible nutrients (TDN) content in forage over their monocrops. Monocrop of oat had less TDN than barley or triticale. Drought reduced the ADF, NDF and TDN contents. The forage NEL, NEM and NEG as well as RFV and NFC showed similar trend as the TDN. Overall, the tested pea + cereal intercrops did not increase DMY over the respective monocrops, but they indicated several nutritional quality benefits. These improvements present opportunities to substitute some grain or supplements in the beef cattle diet with better quality forage by intercrops.
Possibilities of Using Industrial Waste Heat for Heating Greenhouses in Northern Greece
Authors: Vourdoubas John
Published: March 2018

The possibility of using the rejected heat from lignite-fired power plants for heating greenhouses in northern Greece has been examined. Although currently industrial waste heat is used for district heating in a few towns in Greece, its use in agriculture has not been reported so far. Due to many environmental and economic benefits symbiosis of industrial and agricultural activities is promoted in many countries. Greenhouses in northern Greece utilize mainly natural gas as heating fuel. However heat recovery from the existing power plants and its use in greenhouses could increase their energy efficiency and reduce the thermal pollution. It will also decrease the use of fossil fuels in greenhouses and the resulting carbon emissions as well. Their heating requirements have been estimated at 170 W/m2 and the required hot water temperatures are 50-60 oC below the required water temperature in district heating systems, at 120 oC. Currently the price of heat sold in the district heating system in the town of Kozani is 0.0435 €/KWh, which is very attractive for heating greenhouses compared with other existing methods or fuels. It has been estimated that the heat recovery from the power plants at 70 MWth could cover the heating needs of 41.2 ha of modern agricultural greenhouses in northern Greece. Recycling of industrial waste heat in greenhouses in northern Greece, apart from the resulting environmental benefits, will offer a competitive advantage, increasing the profitability of those enterprises.
Doses of Phosphorus in Monoammonium Phosphate form Incorporated in Biodegradable Polymers for Corn
Authors: Martins Mayara M. , Teixeira Filho Marcelo C. M. , Galindo Fernando S. , Buzetti Salatiér , Malmonge José A. , Malmonge Luiz F.
Published: March 2018

The use of monoammonium phosphate (MAP) dissolved in organic polymers can reduce the fixation of phosphorus in the soil, and thus provide greater availability of this nutrient for long-term crops. The objective of this study was to evaluate the effect of doses of phosphorus in conventional form and incorporated MAP in biodegradable polymers, evaluating nutritional status, production components and corn grain yield, as well as the residual effect of P and N. The experiment was conducted in a no- tillage system consolidated for more than 10 years in a Latossolo Vermelho distrófico (Oxisol) with a clay texture located in Selvíria, MS, Brazil. The experimental design was a randomized block design with four replicates, arranged in a 4 × 4 factorial scheme, four forms of MAP (conventional, P1 = polymers with 30% MAP + water, P2 = polymers with 70% MAP + water and P3 = polymers with 30% of MAP), and four doses of P2O5 (0, 60, 120 and 180 kg ha-1), applied soon after emergence of the seedlings in the corn sowing line. Polymer P1 released higher amounts of P to the soil up to the R1 stage of corn, also provided the highest grain yield, indicating to be the most promising for use in Brazilian Cerrado soil.
Nutritional Requirement of Sugarcane Cultivars
Authors: Silva Vinicius S. G. da , Oliveira Mauro W. de , Ferreira Vilma M. , Oliveira Terezinha B. A. , Galvão Elaine R. , Silva Aleksandro F. da , Machado Polyana A. S.
Published: March 2018

Sugarcane produces a large amount of biomass, extracts and accumulates high amounts of nutrients. In the literature the nutritional requirements for most cultivated varieties in the past are found, however there is little information on the new varieties currently planted. The objective of this study was to evaluate the nutritional requirement of four sugarcane varieties, currently very planted, in the cycles of plant-cane, first and second ratoon. The study was installed in a Yellow Oxisol. The experimental design was a randomized block design, with five replications, and four treatments: RB867515, RB92579, SP813250 and VAT90212. During maturation of the cane, in the three evaluation cycles, the productivity of natural biomass and the nutritional requirement of macronutrients of the varieties were determined. It was evidenced that the cultivars of sugarcane are of high productive potential and resemble the accumulation of biomass, observing a yield of 158, 128 and 107 t ha-1 in the cycles of plant-cane, first and second ratoon. Regarding the nutritional requirement, the varieties did not differ among them and expressed the following order of need in the plant-cane K > N > Ca > Mg > S > P, in the first and second ratoon, the sequence observed was K > N > Ca > S > Mg > P.
An Online Professional Development Model to Support Teachers' Abilities to Examine Student Work and Thinking
Authors: Fukawa-Connelly Tim , Klein Valerie , Silverman Jason , Shumar Wesley
Published: March 2018

At the heart of the National Council of Teachers of Mathematics' (NCTM) Principles to Actions: Ensuring Mathematical Success for All (2014) is the development of professional practices such as eliciting and using evidence of student thinking, supporting productive struggle in learning mathematics, and posing purposeful questions. In this article, we share our emerging work in online professional development for teachers, which provides potentially cost-effective ways of scaling high-quality, effective professional development for mathematics teachers by employing the collaborative features of the Internet to mediate professional conversations and interactions. Specifically, we detail the characteristics of our model for online professional development and present cases to illustrate its potential impact on teachers' ability to analyze student work and provide productive feedback.
En/countering Inclusive Mathematics Education: A Case of Professional Learning
Authors: Tan Paulo , King Thorius Kathleen
Published: March 2018

Despite the push for inclusive mathematics education, students with disabilities continue to lack access to, and achievement in, rich mathematics learning opportunities. We assert that mathematics teacher educators have a central role in addressing these contradictions. This role includes enacting facilitative moves during mathematics teacher professional learning to encounter and counter social forces, which we denote in this article as en/counters. As part of a larger study, we explored the extent to which the use of an inclusive education-oriented tool, developed and introduced during a teacher learning program, elicited en/counters that mediated participants' learning toward inclusive mathematics education. We discuss shifts in participants' conversational content and focus on surrounding practices that involved students with disabilities and features of the tool and processes that supported these shifts, including specific facilitative moves that helped redirect deficit-focused conversations.
Use of seaweed Ulva lactuca for water bioremediation and as feed additive for white shrimp Litopenaeus vannamei
Authors: Elizondo-González Regina , Quiroz-Guzmán Eduardo , Escobedo-Fregoso Cristina , Magallón-Servín Paola , Peña-Rodríguez Alberto
Published: March 2018

Two experimental feeding trials were conducted during four weeks to evaluate the use of Ulva lactuca in shrimp culture: (1) for wastewater bioremediation, and (2) using different inclusion levels of U. lactuca meal in shrimp feed. In feeding trial 1, shrimp reared under seaweed U. lactuca water exchange in a re-circulation system (SWE) resulted in similar growth and feed utilization as shrimp reared with clean water exchange (CWE). Shrimp under no water exchange (NWE) resulted in significant lower growth and higher feed conversion rate (FCR) compared to the other treatments (p < 0.05). Nitrogen compounds and phosphate in water from SWE and CWE treatments did not present significant differences during the experimental trial (p > 0.05). In feeding trial 2, U. lactuca biomass produced by wastewater bioremediation in SWE treatment were dried and ground to formulate diets containing 0, 1, 2, and 3% U. lactuca meal (0UL, 1UL, 2UL, and 3UL). Shrimp fed the 3 UL diet resulted in a significant (p < 0.05) improvement of growth and FCR, and enhanced whole shrimp lipid and carotenoid content by 30 and 60%, respectively, compared to control diet. Seaweed U. lactuca is suggested as a desirable species for wastewater bioremediation in integrated aquaculture systems, and its meal as a good feed additive for farmed shrimp.
Evidence for Gravity Wave Seeding of Convective Ionospheric Storms Possibly Initiated by Thunderstorms
Authors: Kelley M. C. , Dao E. V.
Published: March 2018

With the increase in solar activity, the Communication/Outage Forecast System satellite decayed on orbit to below the F peak. As such, we can study the development of convective ionospheric storms and, most importantly, study large‐scale seeding of the responsible instability. For decades, gravity has been suggested as being responsible for the long wavelengths in the range of 200 to 1,000 km, as are commonly observed using airglow and satellite data. Here we suggest that convective thunderstorms are a likely source of gravity waves and point out that recent theoretical analysis has shown this connection to be quite possible.
Diurnal Variations in Global Joule Heating Morphology and Magnitude Due To Neutral Winds
Authors: Billett D. D. , Grocott A. , Wild J. A. , Walach M.‐T. , Kosch M. J.
Published: March 2018

In the polar ionosphere, variations in Joule heating are significantly controlled by changes in plasma convection, such as that brought about by changes in the interplanetary magnetic field. However, another important consideration when calculating Joule heating is the velocity difference between this plasma and the neutral thermosphere colocated with the ionosphere. Neutral wind data are often difficult to obtain on a global scale; thus, Joule heating has often previously been calculated assuming that neutral velocities are small and can therefore be neglected. Previous work has shown the effect of neutral winds on Joule heating estimations to be more significant than originally thought; however, the diurnal variations of the neutrals due to changes in solar pressure gradients and Coriolis forces have yet to have their impact on Joule heating assessed. We show this universal time effect to be significant in calculating Joule heating and thus can differ significantly from that calculated by neglecting the neutrals. In this study, we use empirical models for the neutral wind, conductivities, and magnetic field to create Northern Hemispheric patterns of Joule heating for approximately 800,000 individual plasma convection patterns generated using data from the Super Dual Auroral Radar Network. From this, a statistical analysis of how Joule heating varies in morphology and magnitude with universal time is shown for differing seasons and levels of geomagnetic activity. We find that neutral winds do play a significant role in the morphology and total energy output of Joule heating.
QBO‐MJO Connection
Authors: Zhang Chidong , Zhang Bosong
Published: March 2018

Activities of the Madden‐Julian Oscillation (MJO) in boreal winter has recently been found to be stronger in easterly phases of the stratospheric quasi‐biennial oscillation (QBO) than its westerly phases. This QBO‐MJO connection was investigated in this study using a method that identifies individual MJO events by tracking their eastward propagating signals in precipitation. Stronger MJO activities in QBO easterly phases are a consequence of more MJO days, not larger amplitudes of individual MJO events as previously thought. More MJO days come from more MJO events initiated over the Indian Ocean and their longer duration because of a weaker barrier effect of the Maritime Continent on MJO propagation. Zonal heterogeneity exists in the connection between QBO, MJO, and tropical total precipitation in general. This poses a challenge to our current understanding of the MJO dynamics, which has yet to fully include upper‐tropospheric and stratospheric processes.
Iodine(III) Reagent‐Mediated Intramolecular Amination of 2‐Alkenylanilines to Prepare Indoles
Authors: Zhao Chun‐Yang , Li Kun , Pang Yu , Li Jia‐Qing , Liang Cui , Su Gui‐Fa , Mo Dong‐Liang
Published: March 2018

A variety of 3‐substituted and 2,3‐disubstituted indoles were synthesized efficiently in good yields through the intramolecular amination of 2‐alkenylanilines promoted by readily available iodine(III) reagents in a short reaction time. Mechanistic studies showed that the reaction pathway went through a nitrenium ion and that 3‐acetoxy indoline was the key intermediate in the indole formation. The indole product was easily prepared on a gram scale and amination also proceeded smoothly using catalytic 3,5‐dimethylphenyl iodine in the presence of mCPBA. Furthermore, the indolo[3,2‐a]carbazole scaffold was prepared in good yield in six steps from commercial ortho‐iodoaniline.

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Chiral Ion‐Pair Organocatalyst‐Promoted Efficient Enantio‐selective Reduction of α‐Hydroxy Ketones
Authors: Zhang Yiliang , He Li , Shi Lei
Published: March 2018

The enantioselective reduction of α‐hydroxy ketones with catecholborane has been developed employing 5 mol% of an 1,1′‐bi‐2‐naphthol (BINOL)‐derived ion‐pair organocatalyst. This methodology provides a straightforward access to the corresponding aromatic 1,2‐diols in high yields (up to 90%) with excellent enantioselectivities (up to 97%). Furthermore, the α‐amino ketones also could be reduced with moderate ee values under mild reaction condition.

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Can we build it? Yes we can, but should we use it? Assessing the quality and value of a very large phylogeny of campanulid angiosperms
Authors: Beaulieu Jeremy M. , O'Meara Brian C.
Published: March 2018

Premise of the Study

The study of very large and very old clades holds the promise of greater insights into evolution across the tree of life. However, there has been a fair amount of criticism regarding the interpretations and quality of studies to date, with some suggesting that detailed studies carried out on smaller, tractable scales should be preferred over the increasingly grand syntheses of these data.

Methods

We provided in detail our trials and tribulations of compiling a large, sparsely sampled matrix from GenBank data and inferring a well‐supported, time‐calibrated phylogeny of Campanulidae. We also used a simulation approach to assess tree quality and to study the value of using very large, comprehensive phylogenies in a comparative context.

Key Results

A robust and well‐supported phylogeny can be produced as long as automated procedures are supplemented with some human intervention. In the case of campanulids, the overall topology may be driven not only by particular genes, but also particular sequences for a gene. We also determined that estimates of divergence times should be fairly robust to issues related to clade‐specific heterogeneity. Finally, we demonstrated how relying on results from smaller, younger clades are prone to produce biased interpretations of tropical to temperate evolution across campanulids as a whole.

Conclusions

While we were both surprised and encouraged by the robust and fairly well‐resolved, comprehensive phylogeny of campanulids, challenges still remain. Nevertheless, large phylogenies are inherently valuable in a comparative context if only to attenuate the issue of ascertainment bias.
N‐Alkylation of Aqueous Ammonia with Alcohols Leading to Primary Amines Catalyzed by Water‐Soluble N‐Heterocyclic Carbene Complexes of Iridium
Authors: Fujita Ken‐ichi , Furukawa Shohichi , Morishima Namino , Shimizu Mineyuki , Yamaguchi Ryohei
Published: March 2018

A new catalytic system for the N‐monoalkylation of aqueous ammonia with a variety of alcohols was developed. Water‐soluble dicationic complexes of iridium bearing N‐heterocyclic carbene and diammine ligands exhibited high catalytic activity for this type of reaction on the basis of hydrogen‐transfer processes without generating harmful or wasteful byproducts. Various primary amines were efficiently synthesized by using safe, inexpensive, and easily handled aqueous ammonia as a nitrogen source. For example, the reaction of 1‐(4‐methylphenyl)ethanol with aqueous ammonia in the presence of a water‐soluble N‐heterocyclic carbene complex of iridium at 150 °C for 40 h gave 1‐(4‐methylphenyl)ethylamine in 83 % yield.
Green Organocatalytic Oxidative Methods using Activated Ketones
Authors: Triandafillidi Ierasia , Tzaras Dimitrios Ioannis , Kokotos Christoforos G.
Published: March 2018

Alkenes are very important moieties in organic chemistry and have been employed as starting materials for the synthesis of important organic compounds. In this review, we present organocatalytic reactions in which alkenes play a central role, especially their organocatalytic oxidation to epoxides. This topic plays a pivotal role in our recent research, for which we utilize H2O2 as a green oxidant and a ketone as the catalyst. Extension to other oxidative transformations is also presented.
Computing Crystal Size Distribution by Focused‐Beam Reflectance Measurement when Aspect Ratio Varies
Authors: Unno Joi , Umeda Ryuta , Hirasawa Izumi
Published: March 2018

Chord length distribution (CLD) can be determined by an in‐line measuring system with focused‐beam reflectance measurement, but it can differ from crystal size distribution (CSD). However, expected values of CLD can be calculated from CSD by statistical methods and vice versa. In this study, a correlation equation between crystal size and aspect ratio during cooling crystallization was obtained and a mapping matrix was calculated based on the correlation equation. Then, the suspension obtained in cooling crystallization was sampled and CSDs were measured by microscopy at the same time that CLDs were measured with FBRM. As a result of error evaluation, transformation of CLD into CSD reduced the errors between CLDs and CSDs except in the early stage of crystallization.
Antisolvent Crystallization of Polymorphs of L‐Histidine
Authors: Punmalee Neeranuch , Wantha Lek , Flood Adrian E.
Published: March 2018

Antisolvent crystallization is the most common method to study solvent effects on polymorphic crystallization. L‐Histidine (L‐his) served as a model substance. Acetonitrile, acetone, and methanol were selected as antisolvents, with water as solvent. The formation of L‐his polymorphs in antisolvent crystallization as a function of supersaturation, antisolvent volume fraction, and temperature was studied. The solubility of polymorph A of L‐his decreased with increasing volume fraction of antisolvent and increased with higher temperature. The metastable polymorph B of L‐his was obtained at higher antisolvent volume fraction and supersaturation. At lower antisolvent volume fraction and supersaturation, a mixture of polymorphs A and B was detected.
The role of imaging in women with ischemic heart disease
Authors: Aggarwal Niti R. , Bond Rachel M. , Mieres Jennifer H.
Published: March 2018

Substantial advances and insights in medical technology and treatment strategies, and the focus on sex‐specific research have contributed to a reduction in cardiovascular mortality in women. Despite these advances, ischemic heart disease (IHD) remains the leading cause of cardiovascular morbidity and mortality of women in the Western world. Advances in cardiovascular imaging, over the past 4 decades, have significantly improved the evaluation and management of the full spectrum of coronary atherosclerosis, which contributes to ischemic heart disease. The development of contemporary and novel diagnostic imaging techniques and tools have assumed an expanded role in the evaluation of symptomatic women to detect not only flow‐limiting epicardial coronary stenosis and nonobstructive atherosclerosis, but also ischemia resulting from microvascular dysfunction. IHD is now diagnosed early and with greater accuracy, leading to improved risk assessment and timely therapies in women. In this article, we review the available evidence on the role of contemporary diagnostic imaging techniques in the evaluation of women with suspected IHD.
Long‐term record of Argentine ant invasions reveals enduring ecological impacts
Authors: Menke Sean B. , Ward Philip S. , Holway David A.
Published: March 2018

The ecological effects of species introductions can change in magnitude over time, but an understanding of how and why they do so remains incompletely understood. Clarifying this issue requires consideration of how temporal variation in invader traits affects invasion impacts (e.g., through differential effects on the diversity and composition of native species assemblages). We examine the temporal dynamics of Argentine ant invasions in northern California by resurveying 202 sites first sampled 30–40 yr ago. To test how invasion impacts change over time, we estimated native ant richness and species composition at 20 riparian woodland sites that span a 30‐yr invasion chronosequence. We then use these data to test how variation in two invader traits (aggression and relative abundance) is related to time since invasion and invasion impact. Native ant assemblages along the chronosequence exhibited reduced native ant richness and altered species composition (compared to uninvaded control sites), but the magnitude of these impacts was independent of time since invasion. These results are corroborated by additional temporal comparisons of native ant assemblages at riparian sites sampled 20–30 yr ago. Our findings together illustrate that the impacts of invasions can persist undiminished over at least a 30‐yr time frame and remain evident at regional scales. Although neither invader trait varied with time since invasion, native ant richness declined as the relative abundance of the Argentine ant increased. This latter result supports the hypothesis that factors reducing invader abundance at particular sites can decrease invasion impacts, but also that such changes may be due to site‐specific factors (e.g., abiotic conditions) that affect invader abundance rather than time since invasion per se. Future studies should attempt to differentiate factors that are intrinsic to the process of invasion (e.g., changes in invader populations) from long‐term environmental changes (e.g., climate change) that represent extrinsic influences on the dynamics of invasion.
The volume and type of unhealthy bus shelter advertising around schools in Perth, Western Australia: Results from an explorative study
Authors: Parnell Ashleigh , Edmunds Melinda , Pierce Hannah , Stoneham Melissa J.
Published: March 2018

Issue addressed

Exposure to advertising for unhealthy food, alcohol and gambling has been shown to influence children and adolescents’ behaviours and attitudes. This exploratory study aimed to assess the volume and type of unhealthy bus shelter advertisements near schools in five local government areas in Perth, Western Australia and to monitor whether the volume of unhealthy advertisements varied seasonally.

Methods

The 29 local governments in the Perth metropolitan region were contacted seeking information regarding the locations of bus shelters featuring advertisements in their local government area. Five local governments provided sufficient information for an audit of the bus shelter advertisements in their area to be conducted.

Every bus shelter within 500 m of a school was photographed and the type of advertisement recorded. The advertisements in the food, non‐alcoholic beverage, alcohol, or gambling categories were then classified as being healthy, moderate, or unhealthy. This process was carried out in June, September, December 2016, and March 2017 to ascertain whether the type of advertisements displayed changed depending on the season.

Results

Of the 293 advertisements recorded over the four audits, 31% featured unhealthy products, 3% moderate, and <1% healthy. Only two of the 293 advertisements were classified as being healthy. Seasonal variation in the volume of unhealthy advertisements was not identified.

So what?

Western Australian school students are regularly exposed to unhealthy bus shelter advertisements. Stricter regulation of outdoor advertising is needed to ensure that young people are protected from the influence of unhealthy industries.
A network visualization approach and global stock market integration
Authors: Tong Chen , Chen Jing , Buckle Mike J.
Published: March 2018

This paper applies a visualized network approach to analyse the degree of integration or comovement among global equity markets. We utilize daily prices of stock market indices of 57 countries from January 1997 to August 2012 to establish both a minimum spanning tree network and graph network. We examine network features including connectivity and centrality through a variety of indicators. Our results clearly show that there has been a tendency over time for markets to become more integrated globally even during periods of market stress. The centrality results suggest that the U.S. and Hong Kong markets have been the most dominant markets in their geographic region. For Europe, we find 3 dominant centres, the United Kingdom, France, and Germany in contrast to previous literature suggesting that the United Kingdom was the dominant country. We further identify that Japan and Australia, instead of acting as dominant countries in their region, serve as bridging countries between the region and the rest of the world. Finally, we find that Africa does not form a cluster, and individual African countries tend to connect to other developed markets.
The Effect of Internal Locus of Control on Career Adaptability: The Mediating Role of Career Decision‐Making Self‐Efficacy and Occupational Engagement
Authors: Kim Na‐Rae , Lee Ki‐Hak
Published: March 2018

This study examined the mediating roles of career decision‐making self‐efficacy (a domain‐specific motivational variable) and occupational engagement (a behavioral variable) on the relationship between internal locus of control (a general motivational variable) and career adaptability among college students in South Korea (N= 310). The findings extend past research on career adaptability by identifying a relationship among the variables.
Growth and Characteristics of C8‐BTBT Layer on C‐Sapphire Substrate by Thermal Evaporation
Authors: Moh Aye M. , Khoo Pei Loon , Sasaki Kimihiro , Watase Seiji , Shinagawa Tsutomu , Izaki Masanobu
Published: March 2018

The organic semiconductor 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT) is deposited on a single crystal (0001) Al2O3 (C‐sapphire) by a vacuum thermal evaporation, and effects of the layer thickness and preparation temperature on structural, morphological, optical, and electrical characteristics are investigated with X‐ray diffraction, atomic force microscopy observation, optical absorption measurement, and resistivity measurement with and without light irradiation. The C8‐BTBT layers possess the (001) out‐of‐plane orientation irrespective of the layer thickness and preparation temperature. The C8‐BTBT grains are growing up in direction parallel to the substrate surface keeping almost constant height, and the continuous layer is formed by the coalescence of the C8‐BTBT grains. The grain size of the continuous C8‐BTBT layer increases with raise in preparation temperature. The optical band gap energy could be estimated to be 3.32–3.35 eV regardless of the layer thickness and preparation temperature. The electrical resistivity decreases from 2.1 × 106 to 1.2 × 102 Ω cm with increase in the preparation temperature due to the increase in the grain size, and the light irradiation induce the drastical decrease to 42–28 Ω cm.
Characterization of d and f Electronic States in RSn1.1Ge0.9 (R = Gd, Tb) Compounds by Optical Spectroscopy and Electronic‐Structure Calculations
Authors: Knyazev Yury V. , Lukoyanov Alexey V. , Kuz'min Yury I. , Gupta Sachin , Suresh Krishna G.
Published: March 2018

This paper presents the results of investigations of the electronic structure and optical properties of the GdSn1.1Ge0.9 and TbSn1.1Ge0.9 compounds. Employing the local spin density approximation accounting for strong electronic correlations in the 4f‐shell of rare‐earth ions, that is the LSDA + U method, we carry out the spin‐polarized calculations of band structure. In a broad range of wavelengths the optical constants of the compounds are measured by an ellipsometry method. A number of spectral and electronic characteristics are calculated. Based on the calculated density of states the structural features of optical conductivity for the investigated intermetallic compounds are interpreted in the region of interband absorption.
Transition‐Metal‐Doped α‐MnO2 Nanorods as Bifunctional Catalysts for Efficient Oxygen Reduction and Evolution Reactions
Authors: Lübke Mechthild , Sumboja Afriyanti , McCafferty Liam , Armer Ceilidh F. , Handoko Albertus D. , Du Yonghua , McColl Kit , Cora Furio , Brett Dan , Liu Zhaolin , Darr Jawwad A.
Published: March 2018

Nano‐sized α‐MnO2 nanorods doped with Co or Ru were directly synthesized using a continuous hydrothermal synthesis process (production rate 10 g h−1) and investigated as relatively inexpensive (due to the small Ru content) bifunctional catalysts for both the Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). The materials were extensively characterized using a range of analytical methods; these including Extended X‐Ray Absorption Fine Structure (EXAFS) spectroscopy measurements, which was accompanied by density functional theory studies, in order to elucidate the role of dopants in α‐MnO2 structure. Electrochemical ORR and OER investigations of the as‐prepared doped α‐MnO2 nanomaterials were compared to more expensive Pt/C or RuO2 catalysts. The doped manganese oxide nanomaterials were used as bifunctional catalysts in the positive electrode of zinc air batteries (with oversized zinc metal negative electrode and limited density of discharge window) and displayed excellent performance (the overpotential was 0.77 and 0.68 V for α‐MnO2 modified with 7.6 at% Co and 9.4 at% Ru, respectively). Overall, as a result of doping, this study achieved improved bifunctional catalytic activities of metal oxide catalysts, which was comparable to more expensive alternatives.
Chiral Amino‐Acid‐Amide Based Ionic Liquids as a Stereoselective Organocatalyst in Asymmetric Transfer Hydrogenation of Acetophenone at Room‐Temperature
Authors: Javle Balasaheb R. , Kinage Anil K.
Published: March 2018

Chiral Ionic Liquids (CILs) of amino acid amide were synthesized and used as novel organo catalyst for Asymmetric Transfer Hydrogenation (ATH) of acetophenone at room temperature. The developed CILs show very high yield and excellent enantio‐selectivity in transfer hydrogenation of acetophenone.