bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests
Authors: Zhu Q. , Riley W. J. , Tang J. , Koven C. D.
Published: March 2015

Abstract. Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate, and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3−, and POx (representing the sum of PO43−, HPO42−, and H2PO4−)) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers, and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus, and free NH4+ at a tropical forest site (Tapajos). The overall model posterior uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results imply that the competitiveness (from most to least competitive) followed this order: (1) for NH4+, nitrifiers ~ decomposing microbes > plant roots, (2) for NO3−, denitrifiers ~ decomposing microbes > plant roots, (3) for POx, mineral surfaces > decomposing microbes ~ plant roots. Although smaller, plant relative competitiveness is of the same order of magnitude as microbes. We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately replicated the experimentally observed competition among different nutrient consumers. Although we used as many observations as we could obtain, more nutrient addition experiments in tropical systems would greatly benefit model testing and calibration. In summary, the N-COM model provides an ecologically consistent representation of nutrient competition appropriate for land BGC models integrated in Earth System Models.
Comparing past accumulation rate reconstructions in East Antarctic ice cores using 10Be, water isotopes and CMIP5-PMIP3 models
Authors: Cauquoin A. , Landais A. , Raisbeck G. M. , Jouzel J. , Bazin L. , Kageyama M. , Peterschmitt J.-Y. , Werner M. , Bard E. , Team ASTER
Published: March 2015

Abstract. Ice cores are exceptional archives which allow us to reconstruct a wealth of climatic parameters as well as past atmospheric composition over the last 800 kyr in Antarctica. Inferring the variations in past accumulation rate in polar regions is essential both for documenting past climate and for ice core chronology. On the East Antarctic Plateau, the accumulation rate is so small that annual layers cannot be identified and accumulation rate is mainly deduced from the water isotopic composition assuming constant temporal relationships between temperature, water isotopic composition and accumulation rate. Such an assumption leads to large uncertainties on the reconstructed past accumulation rate. Here, we use high-resolution beryllium-10 (10Be) as an alternative tool for inferring past accumulation rate for the EPICA Dome C ice core, in East Antarctica. We present a high-resolution 10Be record covering a full climatic cycle over the period 269 to 355 ka from Marine Isotope Stage (MIS) 9 to 10, including a period warmer than pre-industrial (MIS 9.3 optimum). After correcting 10Be for the estimated effect of the palaeomagnetic field, we deduce that the 10Be reconstruction is in reasonably good agreement with EDC3 values for the full cycle except for the period warmer than present. For the latter, the accumulation is up to 13% larger (4.46 cm ie yr−1 instead of 3.95). This result is in agreement with the studies suggesting an underestimation of the deuterium-based accumulation for the optimum of the Holocene (Parrenin et al. 2007a). Using the relationship between accumulation rate and surface temperature from the saturation vapour relationship, the 10Be-based accumulation rate reconstruction suggests that the temperature increase between the MIS 9.3 optimum and present day may be 2.4 K warmer than estimated by the water isotopes reconstruction. We compare these reconstructions to the available model results from CMIP5-PMIP3 for a glacial and an interglacial state, i.e. for the Last Glacial Maximum and pre-industrial climates. While 3 out of 7 models show relatively good agreement with the reconstructions of the accumulation–temperature relationships based on 10Be and water isotopes, the other models either underestimate or overestimate it, resulting in a range of model results much larger than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East Antarctic Plateau during glacial–interglacial transition and need to be improved in the future.
Aggregate breakdown and surface seal development influenced by rain intensity, slope gradient and soil particle size
Authors: Arjmand Sajjadi S. , Mahmoodabadi M.
Published: March 2015

Abstract. Aggregate breakdown is an important process which controls infiltration rate (IR) and the availability of fine materials necessary for structural sealing under rainfall. The purpose of this study was to investigate the effects of different slope gradients, rain intensities and particle size distributions on aggregate breakdown and IR to describe the formation of surface seal. To address this issue, 60 experiments were carried out in a 35 × 30 × 10 cm detachment tray using a rainfall simulator. By sieving a sandy loam soil, two sub-samples with different maximum aggregate sizes of 2 mm (Dmax2 mm) and 4.75 mm (Dmax4.75 mm) were prepared. The soils were exposed to two different rain intensities (57 and 80 mm h−1) on several slopes (0.5, 2.5, 5, 10 and 20%) each at three replicates. The result showed that for all slope gradients and rain intensities, the most fraction percentages in soils Dmax2 and Dmax4.75 mm were in the finest size classes of 0.02 and 0.043 mm, respectively. The soil containing finer aggregates exhibited higher transportability of pre-detached material than the soil containing larger aggregates. Also, IR increased with increasing slope gradient, rain intensity and aggregate size under unsteady state conditions because of less development of surface seal. However, under steady state conditions, no significant relationship was found between slope and IR. The findings of this study revealed the importance of rain intensity, slope steepness and soil aggregate size on aggregate breakdown and seal formation, which can control infiltration rate and the consequent runoff and erosion rates.
Friend or faculty: Social networking sites, dual relationships, and context collapse in higher education
Authors: Sugimoto Cassidy , Hank Carolyn , Bowman Timothy , Pomerantz Jeffrey
Published: March 2015

Students and faculty have always interacted informally, on campus and off. Social networking sites (SNSs), like Facebook, introduce another space in which they interact, contributing to a blurring of boundaries between professional and personal personas. Communications on SNSs may be seen as simply an extension of on- and off-campus lives, and hence fall under the same policies governing institutional codes of conduct. The medium however, allowing for the capture and broadcast of events in academic and everyday lives, merits special considerations for contemporary faculty and administrators. The objective of this critical review is synthesize literature discussing dual relationships, context collapse, and digital persistence to contextualize and inform policy development regarding the use of SNSs in higher education. The review will contribute to discussions and decision-making on what should be done in response to these ubiquitous and novel channels for communication, connection and disclosure, and promote awareness of the implications for the connections fostered and the digital traces left behind in networked social spaces.
The Internet, social networking Web sites and political participation research: Assumptions and contradictory evidence
Authors: Casteltrione Isidoropaolo
Published: March 2015

Over the last decade there has been a proliferation of academic studies addressing the relationship between the Internet and politics, with an increasing number of publications focusing on the impact of such a medium on political participation. Within this specific sub-field research has produced contrasting evidence and generated an intense academic debate. Some scholars stressed the positive impact of the Internet on political participation (i.e., optimists), while others minimised its mobilising power, emphasising its tendency to reinforce existing participatory trends (i.e., normalisers) or highlighting its limited or even negative influence on political participation (i.e., pessimists). Similar findings also emerged in relation to social networking Web sites (SNSs), digital platforms that have been the subject of much research in recent years. This paper discusses how two assumptions characterising many studies focusing on the Internet, SNSs and political participation have contributed to the contradictory findings produced by optimists, pessimists and normalisers. The first assumption is the consideration of political participation as an activity aimed exclusively at affecting governments’ actions, either directly or indirectly. This conceptualisation has arguably prevented scholars from grasping the multidimensional nature of political participation and from assessing how the influence of the Internet on this phenomenon can vary according to the different types of political activity. The second assumption is the perception of the Internet as a homogeneous platform and an over-generalised notion of Internet usage. This, in turn, has led researchers to concentrate on the online/off-line distinction and to overlook the impact of different digital tools and various usage practices. This paper argues for a shift in the ways political participation, Internet and SNSs usage are conceptualised and operationalised in academia. It suggests moving away from the polarised debate between optimists, pessimists and normalisers, and adopting a more differential approach through which examining the effects of digital technologies on political participation.
Youth, privacy and online media: Framing the right to privacy in public policy-making
Authors: Lapenta Gry Hasselbalch , Jørgensen Rikke Frank
Published: March 2015

The right to privacy is a fundamental human right defined in international and regional human rights instruments. As such it has been included as a core component of key legislature and policy proceedings throughout the brief history of the World Wide Web. While it is generally recognized in public policy making that the right to privacy is challenged in new ways in a structurally transformed online public sphere, the way in which it has been framed does not seem to acknowledge this transformation. This paper therefore argues for a reformulation of “online privacy” in the current global policy debate. It presents the results of a qualitative study amongst 68 Danish high school students concerning how they perceive, negotiate and control their private sphere when using social media and builds a case for utilizing the results of studies as this to inform the ongoing policy discourses concerning online privacy.
50 years on: Galtung and Ruge's news value factors revisited in online audience building for independent films
Authors: Meissner Nico
Published: March 2015

In 1965, Galtung and Ruge published an influential list of news values. Fifty years later, my article takes this list to demonstrate how mass media principles still apply when building audiences for an independent film in the Internet age. The article builds on the constructivist approach that news values can be actively formulated and stressed. It uses the case study of independent film project 15Malaysia, illustrating how this project, though unknowingly, actively created news value to convince opinion leaders of its worth and, ultimately, build an audience of over two million viewers.
Women Participation in Politics: A Case Study of Afghan Women
Authors: Ibrahim Muhammad , Mussarat Razia
Published: March 2015

Women are awarded minimized role in politics. Political activities are considered the special domain for men. Women are stressed that home is predominant place. The major role related for women is reproduction of human race. The objectives of the study are to discuss concept of political participation and its objectives for women participation in politics. The central aim is to examine the empowerment of women particularly of Afghanistan. The paper focuses on present contribution of afghan women in presidential election of Afghanistan in 2014. The process includes the voice of Afghan women for successful outcome in election 2014. The empirical and analytical analyses have been adapted to forecasting the present status of afghan women by empowering their right not only by casting a vote rather by full political participation. The under discussion issue is voter turn-out after huge participation of women in presidential election. The study will analyse structural causes and customs which limit women opting to pursue elected offices and member of loyia Jirga. The future prospects for Afghan women participation in politics.
The Significance of Political Participation inPolitical Development: A Case Study of Pakistan
Authors: Ibrahim Muhammad , Mussarat Razia
Published: March 2015

The shared and common interweaved concept of public participation for democratization needed accentuate relationship between public and decision makers in democratic institutions. The complex and interwoven issues required more informed citizen. Then it got weighed with debate and discussion for potential decisions. The purpose of the study is to enhance the rate of mobilization high and equality of participation for political development. It also differentiated between modernization and political development. Fast escalations in mobilization and participation, the primary political aspects of modernization, undermine political institutions. The literature that provide is deliberative method for developing principles for public participation. It is art of making people civilized and becoming associated together. It improves the ration and quality of participation in democratization. It is a potential problem to discuss about voting and non-voting. The voting behavior depends upon the techniques of election campaign of political parties. The relation of democracy is linked with political culture has been emphasized. Many authors ponders that democracy rests on a civic culture. The western social scientists as Huntington and Fukuyama connected the religious culture to democratic progression. It is productive for perfection of organization which fortifies democratic institutions for democratization. Public participation decisions are popular decisions. The paper will focus for political development emphasizes on social mobilization and political participation that cause for growth of institutions. That leads to political development of political system of Pakistan.
On Transference:
Authors: Huang Yiju
Published: March 2015

This article draws on insights of trauma studies to intervene in the political realm of revolutionary politics. I analyze French intellectuals' reception of the Chinese Cultural Revolution and characterize it as a transformation from hope and admiration to trauma. The principal aim is to ascertain the historical perspective of Badiou's uninterrupted identification with Maoism and argue that his fidelity to the Cultural Revolution signifies not positivism but passivity of trauma and disavowal of loss.
La enseñanza de la gravitación universal de Newton orientada por la historia y filosofía de la ciencia: una propuesta didáctica con un enfoque en la argumentación
Authors: Teixeira Elder Sales , Freire Junior Olival , Greca Ileana Maria
Published: March 2015

Este trabajo presenta una propuesta didáctica para enseñar la gravitación universal de Newton (GU), orientada por la historia y la filosofía de la ciencia, para promover mejoras en la habilidad de argumentación de los alumnos. Esta propuesta es la culminación de un trabajo más amplio que ya produjo algunos resultados (Teixeira et al., 2010a; Teixeira et al., 2010b). La propuesta incluye algunos textos de referencia para su implementación, siendo uno de ellos presentado en la segunda sección de este trabajo que discute el layout de argumentación de Toulmin (1958/2006), la referencia sobre argumentación que subsidia nuestro trabajo. Presentamos finalmente una síntesis de la secuencia didáctica propuesta y los instrumentos de orientación y evaluación sugeridos para su implementación en la clase.
Redefinir y resignificar la historia de la alquimia: Marie Meurdrac
Authors: Solsona Pairó Núria
Published: March 2015

Los recientes trabajos en historia de la ciencia han permitido redefinir y repensar la historia de la alquimia en la temprana Edad Moderna. Hoy la alquimia ocupa un lugar importante en la historia de las ciencias. A partir del siglo XVI, la alquimia involucró a personas procedentes de diferentes niveles sociales y económicos, artesanos, príncipes, pastores y estudiosos, tanto hombres como mujeres. En la temprana Edad Moderna, muchos alquimistas compartían la inclinación a leer, escribir, producir y hacer, al mismo tiempo. Asimismo realizaron experimentos en el laboratorio de forma sistemática. Un enfoque didáctico que incluya la historia de la ciencia en la educación científica considera útil su introducción para adquirir conocimientos y motivar al alumnado.
Formas del discurso y razonamiento configural de estudiantes para maestros en la resolución de problemas de geometría
Authors: Clemente Francisco , Llinares Salvador
Published: March 2015

Este trabajo tiene como objetivo estudiar la relación entre las formas del discurso generado por los estudiantes para maestro al resolver problemas de geometría de probar y el razonamiento configural. Analizamos las respuestas de 97 estudiantes para maestro a dos problemas de probar para determinar cómo identificaban y relacionaban propiedades geométricas en la deducción de nuevos hechos y propiedades de las figuras. Los resultados muestran tres formas del discurso generado por los estudiantes para maestro para comunicar su resolución: gráfico, texto y una mezcla de los dos; y que las formas del discurso generado no influyen en el truncamiento del razonamiento configural que desencadena los procesos deductivos.
La medicalización de la sociedad, un contexto para promover el desarrollo y uso de conocimientos científicos sobre el cuerpo humano
Authors: Domènech Calvet Ana M. , Máquez Bargalló Conxita , Marbà- Tallada Anna , Roca Tort Montserrat
Published: March 2015

En esta investigación se ha diseñado e implementado una unidad didáctica sobre la medicalización de la sociedad para favorecer el desarrollo de conocimientos científicos. Se analizan: a) las ideas previas de 283 alumnos de 1º de bachillerato y 164 de 3º ESO, b) la evolución de estas ideas, c) el tipo de información con el que justifican actuaciones relacionadas con la automedicación, y, d) las diferencias que se observan en función del curso. Los resultados muestran que, al final de la unidad, las explicaciones de los alumnos se ajustan más al modelo científico y que, aunque hacen referencia a estos conocimientos cuando responden preguntas enmarcadas en un contexto científico, también enfatizan creencias, experiencias y valores personales cuando el contexto pasa a ser cotidiano. Se comentan implicaciones educativas derivadas de los resultados.
Diseño de un cuestionario para evaluar conocimientos didáctico-matemáticos sobre razonamiento algebraico elemental
Authors: Godino Juan D. , Aké Lilia , Contreras Ángel , Estepa Antonio , Fernandez Teresa , Neto Teresa , Wilhelmi Miguel R. , Díaz Carmen , Oliveras María Luisa , Lacasta Eduardo , Lasa Aitzol
Published: March 2015

La promoción del pensamiento algebraico en alumnos de primaria requiere implementar acciones formativas específicas para los profesores, lo que a su vez implica elaborar instrumentos de evaluación del estado de sus conocimientos didáctico - matemáticos sobre el tema. En este trabajo presentamos resultados del estudio realizado para la construcción de un cuestionario de evaluación de los conocimientos didáctico - matemáticos de estudiantes de magisterio sobre razonamiento algebraico elemental. Describimos las categorías de conocimientos algebraicos tenidas en cuenta (estructuras, funciones y modelización) y las categorías de conocimientos didácticos (facetas epistémica, cognitiva, instruccional y ecológica). Así mismo se describen y analizan las tareas incluidas en el cuestionario informando de la validez de contenido del mismo.
Tendencias del profesorado de ciencias en formación inicial sobre las estrategias metodológicas en la enseñanza de las ciencias. Estudio de un caso en Málaga
Authors: Martin Gámez Carolina , Prieto Ruz Teresa , Jiménez López Mª Angeles
Published: March 2015

Fomentar la adquisición en el alumnado de capacidades y actitudes esenciales para ejercer una ciudadanía responsable, requiere de un profesorado de ciencias que aplique estrategias metodológicas con cierto carácter innovador. Por ello, en este trabajo hemos indagado sobre la disposición, que el profesorado de ciencias en formación inicial, tiene a incorporarlas en su enseñanza. Para ello, se diseñó y aplicó un cuestionario conformado por preguntas cerradas y abiertas, en el que participaron 30 estudiantes del Master de Profesorado de Educación Secundaria. Los resultados ponen de manifiesto 4 tendencias, estando la mayoría de los participantes ubicados en la caracterizada por otorgar poco espacio a actividades innovadoras, que permitan al alumnado adoptar un papel protagonista en su propio aprendizaje y desarrollar contenidos que van más allá del aprendizaje conceptual.
El cine de ciencia ficción en la enseñanza de las ciencias en secundaria
Authors: Petit Pérez Mª Francisca
Published: March 2015

Este trabajo se fundamenta en la necesidad de encontrar herramientas que faciliten la tarea del profesorado en la enseñanza de las ciencias en secundaria y que posibiliten una mejora tanto en el aprendizaje como en la motivación del alumnado en las aulas. Se plantea como base para las actuaciones en el aula el uso del cine de ciencia ficción. El trabajo se divide en dos partes. El primer problema de trabajo es la ciencia ficción que conocen los alumnos y los profesores y qué imagen y concepciones alternativas transmite y adquieren los alumnos. El segundo problema es el diseño y realización de actividades en el aula que fomenten la mejora conceptual, de imagen y la actitud hacia las ciencias del alumnado.
Editorial
Authors: Enseñanza de las Ciencias Revista
Published: March 2015

Editorial
Exploratory Assessment of In Situ Measurements of Radioactivity for Single Source
Authors: Saif Uddin Jilani  , Faisal A.K. Afridi  , M. Ayub K. Yousuf Zai  , Afaq Ahmed Siddiqui
Published: March 2015

Radioactive measurements in the decay process of any radioactive sample can be predicted by radioactive-decay law. This predication is based over its average behavior. In actual practice, the radioactive measurements show fluctuations about the average value. For any radioactive sample, there is an exact number which disintegrates in any given unit of time fluctuates around the average value. In counting applications, it is important to estimate this fluctuation because it indicates the repeatability of results of a measurement. This will identify it by using periodogram analysis that depicts the periodicity in the radioactive decay of the given sample of Americium-241. Statistical distributions that the given sample followed with goodness-of-fit tests are examined. Maximum-Likelihood Estimator (MLE) has been used to find the population parameters. The randomness in radioactive decay has been verified by non-parametric method. These statistical analyses are based over the amount of internal fluctuation in the given radioactive source that is consistent with the predictions obtained. These measurements are obtained by measuring the decay of 300 counts per 10 sec. of Americium-241 using a Geiger Muller (GM) Counter in the teaching laboratory, at the | department of Physics, University of Karachi, Karachi, Pakistan.
La distribution à l’heure du multi-canal Une redéfinition du rôle du vendeur
Authors: Vanheems Régine
Published: March 2015

La stratégie multi-canal s’impose désormais comme un impératif pour les enseignes de distribution. De nombreuses enseignes ont implanté un site Internet, en complément de leur(s) magasin(s) et sont devenues « click-and-mortar ». Loin d’être neutre pour les vendeurs, ce site engendre des attentes inédites de la part des clients à leur égard et transforme le contenu de l’échange entre les protagonistes. A partir d’une étude qualitative menée auprès de 35 vendeurs, cet article montre pourquoi il est urgent que les managers revisitent les piliers traditionnels du management de leur force de vente.
Les facettes identitaires de ia consommation. Le cas des cosmétiques chez les deuxièmes générations d’immigration
Authors: Silhouette-Dercourt Virginie , Darpy Denis , de Lassus Christel
Published: March 2015

Cette étude explore la relation des femmes de deuxième génération d’immigration aux marques et aux produits cosmétiques car la consommation de ceux-ci comporte des dimensions identitaires, culturelles, et sociales pour cette cible. Elle met en scène les sentiments d’appartenance culturelle. Cette recherche s’appuie sur deux phases de collecte de données auprès de 31 femmes sur leurs pratiques, les marques et les produits qu’elles utilisent. Le corpus est analysé avec un carré sémiotique. Les marques « d’ici », « de là-bas » et les marques mondiales peuvent travailler les ingrédients utilisés, les formes et couleurs du packaging ainsi que les codes graphiques des déclinaisons produits choisis pour améliorer la perception des dimensions culturelles et rechercher une rupture demandée par les consommatrices.
Right to Inclusive Education for Students with Disabilities in Kenya
Authors: Elder Brent C.
Published: March 2015

This article explores the current inclusive education system in Kenya, and how those practices relate to Article 24 of the United Nations' Convention on the Rights of Persons with Disabilities (CRPD). Local laws and international instruments are presented to shed light on the extent to which students with disabilities have a right to inclusive education in Kenya. Inclusive education is in its nascent stage in Kenya, and many barriers currently exist in the development of an inclusive education system. Such barriers include: poverty, child labor, natural disasters, HIV/AIDS, gender, ethnicity, access to healthcare, access to food, and availability of clean drinking water. In order for Kenya to develop an inclusive education system in accordance with the CRPD, the author proposes the following: development of a country/region-centered plan, implementation of inclusion reports, development of an inclusive network for schools throughout Kenya, and clarification of ambiguous language and terms within Article 24 of the CRPD, as applied to Kenyan laws and policies.
Early Childhood Intervention in China
Authors: Zheng Yuzhu , Maude Susan P. , Brotherson Mary Jane
Published: March 2015

With rapid economic development and increasing awareness of the importance of early childhood intervention (ECI), China is re-examining its social and educational practices for young children with disabilities. This re-examination may have a significant impact on young children with disabilities in China. It may also set an example for other developing nations. This article discusses ECI in China including relevant policies, laws, and practices. Currently, the current policies and laws related to ECI are rarely implemented in China and ECI is facing immense problems. In order to help promote the re-examination of ECI in China, the authors suggest areas of improvement for policies and practices in China in order to better support children, families, and service providers.
Recent glacier decline in the Kerguelen Islands (49°S, 69°E) derived from modeling, field observations, and satellite data
Authors: Verfaillie Deborah , Favier Vincent , Dumont Marie , Jomelli Vincent , Gilbert Adrien , Brunstein Daniel , Gallée Hubert , Rinterknecht Vincent , Menegoz Martin , Frenot Yves
Published: March 2015

The retreat of glaciers in the Kerguelen Islands (49°S, 69°E) and their associated climatic causes have been analyzed using field data and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images to validate a positive degree‐day (PDD) model forced by data from local meteorological stations. Mass balance measurements made during recent field campaigns on the largest glacier of the Cook Ice Cap were compared to data from the early 1970s, providing a 40 year view of the differences in the spatial distribution of surface mass balance (SMB). To obtain additional regional data for the validation of our models, we analyzed MODIS images (2000–2012) to determine if our model was capable of reproducing variations in the transient snow line. The PDD model correctly simulated the variations in the snow line, the spatial variations in the SMB, and its trend with elevation. Yet current SMB values diverge from their classic linear representation with elevation, and stake data at high altitudes now display more negative SMB values than expected. By analyzing MODIS albedo, we observed that these values are caused by the disappearance of snow and associated feedback on melt rates. In addition, certain parts of Ampere Glacier could not be reproduced by the surface energy balance model because of overaccumulation due to wind deposition. Finally, the MODIS data, field data, and our models suggest that the acceleration of glacier wastage in Kerguelen is due to reduced net accumulation and an associated rise in the snow line since the 1970s.
SWARM observations of equatorial electron densities and topside GPS track losses
Authors: Buchert Stephan , Zangerl Franz , Sust Manfred , André Mats , Eriksson Anders , Wahlund Jan‐Erik , Opgenoorth Hermann
Published: March 2015

The SWARM satellites have both upward looking GPS receivers and Langmuir probes. The receivers repeatedly lost track of the L1 band signal in January–February 2014 at postsunset hours, when SWARM was at nearly 500 km altitude. This indicates that the signal was disturbed by ionospheric irregularities at this height and above. The track losses occurred right at density gradients associated with equatorial plasma bubbles and predominantly where the measured background density was highest. The signal showed strong phase scintillations rather than in amplitude, indicating that SWARM might be in the near field of an ionospheric phase screen. Density biteouts, depletions between steep gradients, were up to almost 3 orders of magnitude deep in the background of a more shallow trough centered at the magnetic equator. Comparison between satellites shows that the biteout structure strongly varied in longitude over ∼100 km and has in north‐south steep walls.
Fast and Efficient Synthesis of Z‐Enol‐γ‐Lactones through a Cycloisomerization Reaction of β‐Hydroxy‐γ‐Alkynoic Acids Catalyzed by Copper(I) under Microwave Heating in Water
Authors: López‐Reyes Morelia E. , Toscano R. Alfredo , López‐Cortés José G. , Alvarez‐Toledano Cecilio
Published: March 2015

A diastereo‐ and regioselective method for accessing a variety of highly functionalized Z‐enol‐γ‐lactones in good yields through the cycloisomerization of β‐hydroxy‐γ‐alkynoic acids catalyzed by CuBr (5 mol %) in water under microwave heating in a short time is described.
Phase morphology, thermomechanical, and crystallization behavior of uncompatibilized and PP‐g‐MAH compatibilized polypropylene/polystyrene blends
Authors: Parameswaranpillai Jyotishkumar , Joseph George , Jose Seno , Hameed Nishar
Published: March 2015

In this article, we discuss the phase morphology, thermal, mechanical, and crystallization properties of uncompatibilized and compatibilized polypropylene/polystyrene (PP/PS) blends. It is observed that the Young's modulus increases, but other mechanical properties such as tensile strength, flexural strength, elongation at break, and impact strength decrease by blending PS to PP. The tensile strength and Young's modulus of PP/PS blends were compared with various theoretical models. The thermal stability, melting, and crystallization temperatures and percentage crystallinity of semicrystalline PP in the blends were marginally decreased by the addition of amorphous PS. The presence of maleic anhydride‐grafted polypropylene (compatibilizer) increases the phase stability of 90/10 and 80/20 blends by preventing the coalescence. Hence, finer and more uniform droplets of PS dispersed phases are observed. The compatibilizer induced some improvement in impact strength for the blends with PP matrix phase, however fluctuations in modulus, strength and ductility were observed with respect to the uncompatibilized blend. The thermal stability was not much affected by the addition of the compatibilizer for the PP rich blends but shows some decrease in the thermal stability of the blends, where PS forms the matrix. On the other hand, the % crystallinity was increased by the addition of compatibilizer, irrespective of the blend concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42100.
Is there a clubbing effect underlying Chinese research citation Increases?
Authors: Tang Li , Shapira Philip , Youtie Jan
Published: March 2015

There is increasing evidence that citations to Chinese research publications are rising sharply. A series of reasons have been highlighted in previous studies. This research explores another possibility—whether there is a “clubbing” effect in China's surge in research citations, in which a higher rate of internal citing takes place among influential Chinese researchers. Focusing on the most highly cited research articles in nanotechnology, we find that a larger proportion of Chinese nanotechnology research citations are localized within individual, institutional, and national networks within China. Both descriptive and statistical tests suggest that highly cited Chinese papers are more likely than similar U.S. papers to receive internal and localized citations. Tentative explanations and policy implications are discussed.
Convergence Analysis of Wireless Remote Iterative Learning Control Systems with Channel Noise
Authors: Huang Lixun , Fang Yong , Wang Tao
Published: March 2015

Channel noise, including sensor‐to‐controller(SC) noise and controller‐to‐actuator(CA) noise, impacts the convergence of wireless remote iterative learning control (ILC) system significantly. In this paper, the relationship between output error, SC noise and CA noise is obtained firstly by super‐vector formulation, and then the norm of output error vector covariance matrix is employed to analyze the convergence of the system in presence of SC noise and CA noise. Upper bound of the norm at any sample time reveals that the SC noise is accumulated only in iteration domain, while the CA noise is accumulated not only in iteration domain but also in time domain. Furthermore, the accumulated effect of the CA noise in time domain is ruled by system matrices, so the values of which determine the effect of the CA noise is greater or less than that of the SC noise on convergence of the system. Finally, some simulation results are given to illustrate correctness of the result.
A regularized nonnegative canonical polyadic decomposition algorithm with preprocessing for 3D fluorescence spectroscopy
Authors: Royer Jean‐Philip , Thirion‐Moreau Nadège , Comon Pierre , Redon Roland , Mounier Stéphane
Published: March 2015

We consider blind source separation in chemical analysis focussing on the 3D fluorescence spectroscopy framework. We present an alternative method to process the Fluorescence Excitation‐Emission Matrices (FEEM): first, a preprocessing is applied to eliminate the Raman and Rayleigh scattering peaks that clutter the FEEM. To improve its robustness versus possible improper settings, we suggest to associate the classical Zepp's method with a morphological image filtering technique. Then, in the second stage, the Canonical Polyadic (CP or Candecomp/Parafac) decomposition of a nonnegative three‐way array has to be computed. In the fluorescence spectroscopy context, the constituent vectors of the loading matrices should be nonnegative (since standing for spectra and concentrations). Thus, we suggest a new nonnegative third order CP decomposition algorithm (NNCP) based on a nonlinear conjugate gradient optimization algorithm with regularization terms and periodic restarts. Computer simulations performed on real experimental data are provided to enlighten the effectiveness and robustness of the whole processing chain and to validate the approach. Copyright © 2015 John Wiley & Sons, Ltd.
Synthesis of Onion‐Peel Nanodendritic Structures with Sequential Functional Phosphorus Diversity
Authors: Katir Nadia , El Brahmi Nabil , El Kadib Abdelkrim , Mignani Serge , Caminade Anne‐Marie , Bousmina Mosto , Majoral Jean Pierre
Published: March 2015

The preparation of novel families of phosphorus‐based macromolecular architectures called “onion peel” phosphorus nanodendritic systems is reported. This construct is based on the versatility of methods of synthesis using several building blocks and on the capability of these systems to undergo regioselective reactions within the cascade structure. Sustainable metal‐free routes such as the Staudinger reaction or Schiff‐base condensation, involving only water and nitrogen as byproducts, allow access to several dendritic macromolecules bearing up to seven different phosphorus units in their backbone, each of them featuring specific reactivity. The presence of the highly aurophilic PNPS fragment enables selective ligation of AuI within the dendritic framework.
ChemInform Abstract: Diastereo‐ and Enantioselective Valorization of Cyclic Organic Carbonates
Authors: Kleij Arjan W. , Whiteoak Christopher J.
Published: March 2015

Review: 14 refs.
ChemInform Abstract: Time‐Resolved Resonance Raman Spectroscopic Studies of Aryl Nitrenium Ions and Their Chemical Reactions
Authors: Phillips David Lee
Published: March 2015

Review: 93 refs.
Die wirtschaftliche Nutzung von Power‐to‐Heat‐Anlagen im Regelenergiemarkt
Authors: Pieper Christoph , Sykora Nancy , Beckmann Michael , Böhning Dorith , Hack Nina , Bachmann Tobias
Published: March 2015

Die Energiewende stellt in Deutschland einen gewaltigen Umbruch dar und somit alle Marktteilnehmer vor neue Herausforderungen. Durch den zunehmenden Einfluss der fluktuierenden Energiequellen steigt der Bedarf an flexiblen Leistungseinheiten zur Sicherung der Netzstabilität. Daraus ergeben sich im wandelnden Markt neue Chancen zur Erwirtschaftung von Gewinnen, da die heute diskutierten Speichertechnologien nur zum Teil großtechnisch verfügbar und zugleich wirtschaftlich sind. Dieser Artikel diskutiert Möglichkeiten der Wandlung von Strom in Wärme (Power‐to‐Heat) und zeigt, dass durch die Bereitstellung von Regelenergie eine ökonomische Bewirtschaftung möglich ist.
Weiterentwicklung und Charakterisierung eines Spinning‐Disc‐Reaktors nach dem Rotor‐Stator‐Prinzip
Authors: Haseidl Franz , Schuh Patrick , Hinrichsen Kai‐Olaf
Published: March 2015

Ein vielversprechendes Reaktorkonzept zur Prozessintensivierung stellt der Spinning‐Disc‐Reaktor (SDR) dar. Im Rahmen dieser Arbeit wurde der Reaktor zu einem SDR nach dem Rotor‐Stator‐Prinzip weiterentwickelt, wobei die rotierende Scheibe von einem zylindrischen Stator umgeben ist. Zum besseren Verständnis der Vorgänge in dem dünnen, stark gescherten Flüssigkeitsfilm wird die Mikrovermischung mithilfe der Villermaux‐Dushman‐Reaktion untersucht. Darüber hinaus erfolgt eine systematische Untersuchung der Einflussparameter auf die Stoffübergangsvorgänge bei der heterogen katalysierten Glucose‐Oxidation. Hierzu wird ein Pt/C‐Katalysator auf der Scheibe immobilisiert.
Formation of longitudinal aggregation of inclusions in bulk sapphire and yttrium‐aluminum garnet grown by horizontal directed crystallization method
Authors: Nizhankovskyi S. V. , Tan'ko A. V. , Sidelnikova N. S. , Adonkin G. T.
Published: March 2015

It is shown that the formation of longitudinal aggregation of inclusions in bulk sapphire and yttrium‐aluminum garnet (YAG) grown by the method of HDC is caused by local accumulation of impurities, disturbance of morphological stability of the crystallization front and capture of inclusions and impurities in the nodal region of the melt two‐vortex convection. Studied is the influence of thermal and geometrical parameters of the melt and the shape of the crystallization front on the conditions of the formation of the capture of inclusions.
Bridgman growth and characterization of birefringent crystal NaNO3
Authors: Xiong Wei , Chen Liang , Huang Lingxiong , Guo Feiyun , Zhou Yao , Yuan Hui
Published: March 2015

With a bigger birefringence than calcite, sodium nitrate (NaNO3) single crystal might have potential applications in fiber‐optic polarizer, opto‐isolators and polarizing prisms. However, it is difficult to grow large‐size NaNO3 crystals for their thermal conductivity anisotropy and phase transition at 275°C. In this paper, crack‐free NaNO3 crystals with size of Φ20×100 mm3 were prepared by Bridgman method with lower growth rate and lower interface temperature gradient. The dependence of the transmittance on the sample exposure time was measured and studied. The principal refractive indices of NaNO3 crystal at the wavelengths 0.4730, 0.5320, 0.6328, 1.064 and 1.338 μm were measured by auto‐collimation method. From which, we calculated and obtained the Sellmeier's equation of NaNO3 crystal. Moreover, the photoluminescence spectra were detected under the excitation at 240 nm, and NaNO3 crystal presented its fluorescence around 416 nm.
MicroRNA signatures differentiate preserved from reduced ejection fraction heart failure
Authors: Watson Chris J. , Gupta Shashi K. , O'Connell Eoin , Thum Sabrina , Glezeva Nadezhda , Fendrich Jasmin , Gallagher Joe , Ledwidge Mark , Grote‐Levi Lea , McDonald Kenneth , Thum Thomas
Published: March 2015

Aims

Differentiation of heart failure with reduced (HFrEF) or preserved (HFpEF) ejection fraction independent of echocardiography is challenging in the community. Diagnostic strategies based on monitoring circulating microRNA (miRNA) levels may prove to be of clinical value in the near future. The aim of this study was to identify a novel miRNA signature that could be a useful HF diagnostic tool and provide valuable clinical information on whether a patient has HFrEF or HFpEF.

Methods and results

MiRNA biomarker discovery was carried out on three patient cohorts, no heart failure (no‐HF), HFrEF, and HFpEF, using Taqman miRNA arrays. The top five miRNA candidates were selected based on differential expression in HFpEF and HFrEF (miR‐30c, −146a, −221, −328, and −375), and their expression levels were also different between HF and no‐HF. These selected miRNAs were further verified and validated in an independent cohort consisting of 225 patients. The discriminative value of BNP as a HF diagnostic could be improved by use in combination with any of the miRNA candidates alone or in a panel. Combinations of two or more miRNA candidates with BNP had the ability to improve significantly predictive models to distinguish HFpEF from HFrEF compared with using BNP alone (area under the receiver operating characteristic curve >0.82).

Conclusion

This study has shown for the first time that various miRNA combinations are useful biomarkers for HF, and also in the differentiation of HFpEF from HFrEF. The utility of these biomarker combinations can be altered by inclusion of natriuretic peptide. MiRNA biomarkers may support diagnostic strategies in subpopulations of patients with HF.
Partial coalescence in emulsions: The impact of solid fat content and fatty acid composition
Authors: Munk Merete B. , Andersen Mogens L.
Published: March 2015

Oil‐in‐water emulsions were made with five different triglyceride fats ranging from completely liquid oil to solid. Regardless of the type of dispersed fat, all emulsions were non‐aggregated and low viscous when stabilized only by caseinate. Presence of lactic acid ester of monoglyceride (LACTEM) and unsaturated monoglyceride (GMU) caused solidification of emulsions made with fat with intermediate solid fat content (SFC), due to fat globule aggregation. The hardest and most compact fat globule network was obtained for emulsions based on hydrogenated palm kernel oil (HPKO). Although palm kernel oil (PKO) and palm oil (PO) resembled HPKO in terms of fatty acid (FA) composition and SFC, a lower strength of the fat globule network was obtained for emulsions based on PKO and PO. The dispersed fat phase should have intermediate SFC (simultaneous presence of liquid and solid fat) in order to induce fat globule aggregation in emulsions. This was demonstrated by emulsions made with either rapeseed oil (RO) and fully hydrogenated palm oil (FHPO), which remained stable and pourable despite the presence of LACTEM and GMU.

Practical applications: This study emphasizes the important role of fat on the texture of O/W‐emulsions. This knowledge is vital for the industry in order to control or avoid fat globule aggregation. For manufacturers striving for partial coalescence of emulsions to occur, it is necessary to use low‐molecular‐weight emulsifiers and fat with intermediate solid fat content.

Emulsions stabilized by sodium caseinate remained stable and non‐aggregated independent of the type of dispersed fat. When emulsions were stabilized by a combination of sodium caseinate, LACTEM, and GMU, partial coalescence occurred for fat globules with intermediate solid fat content while globules of either solid fat or liquid oil remained stable.