bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonographic examination of joints, a revolution in equine locomotor pathology
Authors: Denoix Jean-Marie
Published: October 2014

L’échographie des articulations, une révolution en pathologie locomotrice équine.

D’abord utilisée pour le diagnostic et la documentation des lésions tendineuses, l'échographie est devenue depuis 1990 un complément indispensable à la radiologie dans le diagnostic des affections articulaires chez le cheval. Cette technique fournit des informations précises sur la membrane et le contenu synovial, le cartilage articulaire et l'os sous-chondral, les marges articulaires, les ligaments et les ménisques, ainsi que sur les formations impliquées lors d’épaississement péri-articulaire. L''amélioration des appareils et de la résolution de l''image, en régions superficielles comme en profondeur, permettent maintenant d'envisager l'examen de toutes les articulations des membres, y compris les plus proximales, et de la plupart des articulations axiales (colonne vertébrale, bassin et tête) du cheval. En 20 ans, un grand nombre d’entités pathologiques nouvelles ont été mises en lumière grâce à l’échographie ; ces connaissances ont profondément changé l’approche diagnostique et la compréhension des boiteries chez le cheval. Athlète professionnel, le cheval constitue un excellent modèle animal de pathologie locomotrice sportive spontanée ; la taille de ses formations anatomiques facilite et améliore la documentation lésionnelle par imagerie. L'échographie articulaire nécessite une codification stricte de l'abord technique de chaque formation et une connaissance précise de l'anatomie de l’appareil locomoteur du cheval, conditions indispensables pour garantir les performances de la technique en matière de sensibilité et de spécificité.
Atomic oxygen retrievals in the MLT region from SCIAMACHY nightglow limb measurements
Authors: Lednyts'kyy O. , von Savigny C. , Eichmann K.-U. , Mlynczak M. G.
Published: October 2014

Abstract. Vertical profiles of atomic oxygen concentration in the mesosphere and lower thermosphere (MLT) region were retrieved from sun-synchronous SCIAMACHY/Envisat limb observations of the oxygen 557.7 nm green line emission occurring in the terrestrial nightglow. A band pass filter with noise detection was applied to eliminate contributions from other emissions, the impact of noise and auroral activity. Assuming horizontal homogeneity of each atmospheric layer, and absence of absorption and scattering, vertical volume emission rate profiles were retrieved from integrated limb emission rate profiles. The radiative transfer problem was treated with a linear forward model and inverted using regularized total least squares minimization. Atomic oxygen concentration ([O]) profiles were retrieved at altitudes from 85 to 105 km with approximately 4 km vertical resolution for the period from August 2002 to April 2012 at a constant local time (LT) of approximately 22:00. The retrieval of [O] profiles was based on the generally accepted 2-step Barth transfer scheme including consideration of quenching processes and the use of different available sources of temperature and atmospheric density profiles. A sensitivity analysis was performed for the retrieved [O] profiles to estimate the maximum uncertainty, assuming independent contributions of uncertainty components. The retrieved [O] profiles were compared with reference [O] profiles measured by SABER/TIMED and modelled using NRLMSISE-00 and SD-WACCM4. A comparison of the retrieved [O] profiles with the reference [O] profiles enabled the selection of the most appropriate photochemical model accounting for quenching processes and the most appropriate source of temperature and density profiles for further application of our approach to the [O] profile retrieval. The obtained [O] profile time series show characteristic seasonal variations in agreement with atmospheric models and satellite observations based on analysis of OH Meinel band emissions. Furthermore, a pronounced 11 year solar cycle variation can be identified in the atomic oxygen concentration time series, which will be the subject of further studies.
Surface circulation and upwelling patterns around Sri Lanka
Authors: de Vos A. , Pattiaratchi C. B. , Wijeratne E. M. S.
Published: October 2014

Abstract. Sri Lanka occupies a unique location within the equatorial belt in the northern Indian Ocean, with the Arabian Sea on its western side and the Bay of Bengal on its eastern side, and experiences bi-annually reversing monsoon winds. Aggregations of blue whale (Balaenoptera musculus) have been observed along the southern coast of Sri Lanka during the northeast (NE) monsoon, when satellite imagery indicates lower productivity in the surface waters. This study explored elements of the dynamics of the surface circulation and coastal upwelling in the waters around Sri Lanka using satellite imagery and numerical simulations using the Regional Ocean Modelling System (ROMS). The model was run for 3 years to examine the seasonal and shorter-term (~10 days) variability. The results reproduced correctly the reversing current system, between the Equator and Sri Lanka, in response to the changing wind field: the eastward flowing Southwest Monsoon Current (SMC) during the southwest (SW) monsoon transporting 11.5 Sv (mean over 2010–2012) and the westward flowing Northeast Monsoon Current (NMC) transporting 9.6 Sv during the NE monsoon, respectively. A recirculation feature located to the east of Sri Lanka during the SW monsoon, the Sri Lanka Dome, is shown to result from the interaction between the SMC and the island of Sri Lanka. Along the eastern and western coasts, during both monsoon periods, flow is southward converging along the southern coast. During the SW monsoon, the island deflects the eastward flowing SMC southward, whilst along the eastern coast, the southward flow results from the Sri Lanka Dome recirculation. The major upwelling region, during both monsoon periods, is located along the southern coast, resulting from southward flow converging along the southern coast and subsequent divergence associated with the offshore transport of water. Higher surface chlorophyll concentrations were observed during the SW monsoon. The location of the flow convergence and hence the upwelling centre was dependent on the relative strengths of wind-driven flow along the eastern and western coasts: during the SW (NE) monsoon, the flow along the western (eastern) coast was stronger, migrating the upwelling centre to the east (west).
Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean
Authors: Lasbleiz M. , Leblanc K. , Blain S. , Ras J. , Cornet-Barthaux V. , Hélias Nunige S. , Quéguiner B.
Published: October 2014

Abstract. The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October–November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m−2 for chlorophyll a 314 to 744 mmol m−2 for biogenic silica (BSi), 1106 to 2268 mmol m−2 for particulate organic carbon, 215 to 436 mmol m−2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m−2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the polar front zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size–fractionation and high performance liquid chromatography (HPLC) pigment signatures, whereas the iron-limited reference area was associated with a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from most previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9, respectively) in the iron-fertilized areas compared to the iron-limited reference station (0.13, 1.1, and 5.8, respectively). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From particulate organic carbon (POC), particulate organic nitrogen (PON), and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the phytoplankton community structure as well as major changes in the nutrient stocks progressively leading to silicic acid exhaustion at the end of the productive season. Our observations suggest that the specific response of phytoplankton communities under natural iron fertilization is much more diverse than what has been regularly observed in artificial iron fertilization experiments and that the elemental composition of the bulk particulate matter reflects phytoplankton taxonomic structure rather than being a direct consequence of iron availability.
Determining the focal mechanisms of the events in the Carpathian region of Ukraine
Authors: Pavlova A. , Hrytsai O. , Malytskyy D.
Published: October 2014

Abstract. The modification of the matrix method for constructing the displacement field on the free surface of an anisotropic layered medium is presented. The source of seismic waves is modelled by a randomly oriented force and seismic tensor. A trial and error method is presented for solving the inverse problem of determining parameters of the earthquake source. A number of analytical and numerical approaches to determining the earthquake source parameters, based on the direct problem solutions, are proposed. The focal mechanisms for the events in the Carpathian region of Ukraine are determined by the graphical method. The theory of determination of the angles of orientation of the fault plane and the earthquake's focal mechanism are presented. The focal mechanisms obtained by two different methods are compared.
Catalytic and thermal characterisations of nanosized PdPt / Al2O3 for hydrogen detection
Authors: Mazingue T. , Lomello-Tafin M. , Passard M. , Hernandez-Rodriguez C. , Goujon L. , Rousset J.-L. , Morfin F. , Laithier J.-F.
Published: October 2014

Abstract. Palladium platinum (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects. These remarkable properties have been studied by measuring the temperature variations of alumina (Al2O3) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterisations and catalytic activity of PdPt / Al2O3 systems synthesised by co-impregnation will be presented. Catalytic characterisations show that the system is already active at room temperature and that this activity sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process improves the activity, and very high conversion can be reached even at room temperature. The thermal response (about 3 °C) of only 1 mg of PdPt / Al2O3 is reversible, and the time response is about 5 s. The integration of PdPt / Al2O3 powder on a flat substrate has been realised by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.
A method to generate fully multi-scale optimal interpolation by combining efficient single process analyses, illustrated by a DINEOF analysis spiced with a local optimal interpolation
Authors: Beckers J.-M. , Barth A. , Tomazic I. , Alvera-Azcárate A.
Published: October 2014

Abstract. We present a method in which the optimal interpolation of multi-scale processes can be expanded into a succession of simpler interpolations. First, we prove how the optimal analysis of a superposition of two processes can be obtained by different mathematical formulations involving iterations and analysis focusing on a single process. From the different mathematical equivalent formulations, we then select the most efficient ones by analyzing the behavior of the different possibilities in a simple and well-controlled test case. The clear guidelines deduced from this experiment are then applied to a real situation in which we combine large-scale analysis of hourly Spinning Enhanced Visible and Infrared Imager (SEVIRI) satellite images using data interpolating empirical orthogonal functions (DINEOF) with a local optimal interpolation using a Gaussian covariance. It is shown that the optimal combination indeed provides the best reconstruction and can therefore be exploited to extract the maximum amount of useful information from the original data.
Effects of bottom topography on dynamics of river discharges in tidal regions: case study of twin plumes in Taiwan Strait
Authors: Korotenko K. A. , Osadchiev A. A. , Zavialov P. O. , Kao R.-C. , Ding C.-F.
Published: October 2014

Abstract. The Princeton Ocean Model (POM) is used to investigate the intratidal variability of currents and turbulent mixing and their impact on the characteristics and evolution of the plumes of two neighbouring rivers, the Zhuoshui River and the Wu River, at the central eastern coast of Taiwan Strait. The two estuaries are located close to each other and their conditions are similar in many respects, and yet the two plumes exhibit significantly different behaviour. We explain this through differences of the bottom topography in the areas adjacent to the two river mouths. The Zhuoshui River runs into a shallow area that is permanently exposed to strong tidal mixing, while the Wu River mouth is located in a deeper, stratified area outside the region of intense mixing. This destruction of the plume by tidal mixing is confirmed by the results of numerical modeling with POM. The spatial and temporal variability of turbulent kinetic energy, the rates of its production by shear and destruction rate by buoyancy in the study, as well as the horizontal diffusivity, are analysed with the emphasis given to the dependence of the turbulence parameters on the bottom topography on the one hand and their influence on the river plumes on the other. The results of the study support the central hypothesis of this paper: the dynamic behaviours of the Zhuoshui and Wu plumes are different because their evolution occurs under different regimes of bottom-generated turbulent mixing. Further, we use a Lagrangian particle tracking model in combination with POM to investigate the effect of the tidal wetting-and-drying (WAD) near the Zhuoshui River estuary, and demonstrate that WAD leads to significant reduction of the plume extent and surface salinity deficit near the river mouth. We use observational data from a short field campaign in the study area to tune and validate the model experiments.
Permafrost soils and carbon cycling
Authors: Ping C. L. , Jastrow J. D. , Jorgenson M. T. , Michaelson G. J. , Shur Y. L.
Published: October 2014

Abstract. Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon (OC) stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous OC stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global C cycle and the potential vulnerability of the region's soil OC stocks to changing climatic conditions. In this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of OC stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this OC to permafrost thaw under a warming climate.
The 1562 Head Injury of Don Carlos: A Conflict of Medicine and Religion in Sixteenth-Century Spain
Authors: Villalon Andrew
Published: October 2014

This article deals with one of the best documented medical cases of the sixteenth century—a near fatal head injury suffered in 1562 by Don Carlos (1545–68), son of Philip II and heir to the Spanish throne. It examines the highly detailed contemporary sources that shed light on the injury and its treatment and then explores the relationship between them. It also explores the conflicting claims of medicine and religion to explain the prince's seemingly miraculous cure and the canonization of the first Counter-Reformation saint, San Diego de Alcalá, that resulted directly from this healing.
Stable isotopes in arid and semi-arid forest systems
Authors: Ferrio J. P. , Resco V. , Williams D. G. , Serrano L. , Voltas J.
Published: October 2014

The use of stable isotope techniques in forest ecology research has grown steadily over the last two decades. This trend will continue, as stable isotopes can serve as valuable integrators of how plants have interacted, today and in the past, with their physical environment or with other organisms. This is particularly relevant in dry areas due to the strong limitation of resources. After a brief introduction about the theoretical background of stable isotopes in plant physiology, this review highlights recent advances in forest ecology that have embraced this methodology, at different spatial and temporal scales, and with special emphasis on arid and semi-arid systems.
Forest dynamics: a broad view of the evolution of the topic, including some recent regional contributions
Authors: Terradas Jaume
Published: October 2014

During the last two centuries, social perception of forest roles has suffered deep changes. New environmental roles, i.e. CO2 storage and biodiversity, have been added to erosion control and watershed regulation. These changes require new knowledge and tools to develop a new understanding of forest dynamics. Some come from studies on past vegetation responses to climate changes. I recall here some old ideas on plant communities and their dynamics in ecology and forestry and the trend to use quantitative and modelling approaches under a new community concept based on environmental constraints, life-histories of available species and disturbances. New succession mechanisms have been added to the Clementsian facilitation, legacy after disturbance is now considered essential and succession has been described as a cycle by including the phases of community decline and resources and space liberation. I summarize some ideas related to Mediterranean ecosystems and to the relation between forest dynamics and global change and I review some main types of models used in forest dynamics studies. Finally, I consider fire ecology and some advances made in our institute on this topic.
Political Jurisprudence or Institutional Normativism? Maintaining the Difference Between Arendt and Fuller
Authors: Wilkinson Michael
Published: October 2014

Political Jurisprudence or Institutional Normativism? Maintaining the Difference Between Arendt and Fuller

Can jurisprudence fruitfully pursue a synthesis of Arendt’s political theory and Fuller’s normative legal philosophy? Might their ideas of the juridical person and the legal subject be aligned as a result of a shared concern for the value of legality, specifically of an institutional complex which is structured through the stability and predictability of the rule of law? It is doubtful that Arendt's concern for the phenomena of plurality, political freedom and action can usefully be brought into line with Fuller's normativist focus on legality, subjectivity and the inner morality of law. This doubt is explored by juxtaposing Arendt's theory of action and her remarks on the revolution, foundation and augmentation of power and authority with Fuller's philosophy that, however critical of its positivist adversaries, remains ultimately tied to a Hobbesian tradition which views authority and power in abstract, hierarchical and individualist terms.
Analysis of Addenda in Anatomic Pathology as a Quality Monitoring Initiative
Authors: Babwah Jesse Paul , Khalifa Mahmoud , Rowsell Corwyn
Published: October 2014

Context

Along with the integration of immunohistochemical markers and molecular techniques into routine practice, addenda in surgical pathology reporting have not only increased in frequency but also evolved to include prognostic and therapeutic information. Because of the lack of uniform practice with respect to issuing addenda, information that can significantly change the diagnosis, prognosis, or treatment plan may be issued as an addendum as opposed to an amendment.

Objective

To audit addenda and identify instances of amendments masquerading as addenda.

Design

All addenda during a 36-month period were reviewed. Each addendum report was classified by accession class, issuing pathologist, subspecialty category, indication for addendum, whether the addendum constituted a change in diagnostic meaning, whether a change in prognosis occurred, and if a change in treatment plan was necessary.

Results

All cytology and autopsy addenda were deemed appropriate. Thirty-three of 5028 (6.5 of 1000) surgical pathology addenda were deemed to have changes: Among the 33 faux addenda, 30 (91%) contained supplemental diagnostic information that would alter patient management and 31 (94%) contained additional information that would change the prognosis from that entailed by the original diagnosis.

Conclusions

Our study demonstrates that not infrequently, surgical pathology addenda contain information that significantly alters the report and thus merit an amendment. Quality monitoring initiatives that evaluate pathologist and departmental performance should assess both addenda and amendments.
Concise Review: Different Mesenchymal Stromal/Stem Cell Populations Reside in the Adult Kidney
Authors: Bruno Stefania , Chiabotto Giulia , Camussi Giovanni
Published: October 2014

During fetal life, mesenchymal stromal/stem cells (MSCs) surround glomeruli and tubules and contribute to the development of the renal interstitium by secretion of growth factors that drive nephron differentiation. In the adult, an MSC-like population has been demonstrated in different compartments of human and murine nephrons. After injury, these cells might provide support for kidney regeneration by recapitulating the role they have in embryonic life. In this short review, we discuss the evidence of an MSC presence within the adult kidney and their potential contribution to the turnover of renal cells and injury repair.
Proceedings: Consideration of Genetics in the Design of Induced Pluripotent Stem Cell-Based Models of Complex Disease
Authors: Grieshammer Uta , Shepard Kelly A.
Published: October 2014

The goal of exploiting induced pluripotent stem cell (iPSC) technology for the discovery of new mechanisms and treatments of disease is being pursued by many laboratories, and analyses of rare monogenic diseases have already provided ample evidence that this approach has merit. Considering the enormous medical burden imposed by common chronic diseases, successful implementation of iPSC-based models has the potential for major impact on these diseases as well. Since common diseases represent complex traits with varying genetic and environmental contributions to disease manifestation, the use of iPSC technology poses unique challenges. In this perspective, we will consider how the genetics of complex disease and mechanisms underlying phenotypic variation affect experimental design.
Les perceptions des enseignants-chercheurs de l’Université libre de Bruxelles à propos de l’évaluation des enseignements
Authors: Salcin Alice , Wéry France , Emplit Philippe , Robert Frédéric
Published: October 2014

Cet article présente une partie des résultats d’une enquête menée en 2010 auprès des enseignants-chercheurs nommés à titre définitif de l’Université libre de Bruxelles (ULB). Cette étude avait pour objectif de mieux connaître la mission d’enseignement de cette population et de permettre, tant aux autorités de l’université qu’aux acteurs concernés par l’aide aux étudiants et aux enseignants, de mieux connaître les besoins et la réalité du métier de professeur d’université, à travers l’identification des représentations des enseignants-chercheurs concernant leur mission d’enseignement. Dans cette contribution, les auteurs tentent de répondre plus précisément à deux questions relatives à l’évaluation des enseignements: d’une part, quels seraient les meilleurs procédés pour acquérir des compétences pédagogiques (les feedbacks des étudiants en étant un possible) et, d’autre part, quelles sont les perceptions des enseignants universitaires quant à la valorisation de leur mission d’enseignement dans leur progression de carrière.
Le savoir-évaluer comme politique éducative
Authors: Tochon François Victor
Published: October 2014

L’évaluation vécue dans les écoles américaines a changé de rôle. De l’évaluation à dimension humaine, nous sommes passés, dans de nombreux pays, à une évaluation de performance standardisée et quantitative dont la fonction est politique, que cet essai analyse de façon critique au vu des recherches sur la validité des tests standardisés. Dans leur évaluation de terrain, les enseignants tendent à tenir compte des facteurs humains, au contraire des mesures standardisées qui contribuent à refaçonner l’enseignement selon les prescriptions des législateurs. La tendance actuelle en matière d’évaluation scolaire porte la raison instrumentale à son extrême, comme si les machines et les critères bureaucratiques pouvaient remplacer les agents humains. Elle peut porter un large préjudice aux minorités linguistiques. L’évaluation est toujours relative car elle dépend d’une interprétation conceptuelle et du contexte d’application. Une approche plus humaine est proposée.
Un modèle en pistes causales pour appréhender la complexité du phénomène d’accrochage scolaire lors de la transition primaire-secondaire
Authors: Poncelet Débora , Lafontaine Dominique
Published: October 2014

Tous les élèves sont affectés d’une manière ou d’une autre par le passage du primaire au secondaire. La recherche suggère que l’échec scolaire constitue un des explicateurs les plus puissants du décrochage scolaire. Le décrochage scolaire est un phénomène multidimensionnel dont les différents facteurs explicatifs sont interdépendants. En plus des facteurs individuels, différentes études ont mis en évidence la relation qui existe entre certaines caractéristiques familiales et le risque de décrochage scolaire : niveau socio-économique, soutien parental, engagement, supervision, valeurs et attentes scolaires sont autant d’éléments issus du monde familial susceptibles d’apporter un éclairage dans la compréhension du décrochage scolaire. Le présent article s’intéresse plus particulièrement à l’étude des perceptions des élèves à l’égard de différents aspects inhérents au milieu familial, à l’école ainsi qu’à différents facteurs de risque associés au jeune durant la période de la transition primaire-secondaire. Il s’agit également de voir comment ces différents facteurs s’influencent mutuellement pour une période scolaire donnée mais aussi de façon longitudinale sur trois années scolaires. Nous recourons à un modèle en pistes causales pour prédire le risque de décrochage scolaire au départ des différents facteurs mesurés. Nos résultats mettent en évidence le rôle central joué par trois variables individuelles dans l’explication directe et indirecte de nos critères : le sentiment du jeune par rapport à l’école et à sa scolarité ainsi que les résultats scolaires. Au vu de nos résultats, il ressort que le comportement social, les méthodes de travail et l’intégration sociale interviennent de façon significative dans le processus d’accrochage scolaire.
Fine‐suspended sediment and water budgets for a large, seasonally dry tropical catchment: Burdekin River catchment, Queensland, Australia
Authors: Bainbridge Zoë T. , Lewis Stephen E. , Smithers Scott G. , Kuhnert Petra M. , Henderson Brent L. , Brodie Jon E.
Published: October 2014

The Burdekin River catchment (∼130,400 km2) is a seasonally dry tropical catchment located in north‐east Queensland, Australia. It is the single largest source of suspended sediment to the Great Barrier Reef (GBR). Fine sediments are a threat to ecosystems on the GBR where they contribute to elevated turbidity (reduced light), sedimentation stress, and potential impacts from the associated nutrients. Suspended sediment data collected over a 5 year period were used to construct a catchment‐wide sediment source and transport budget. The Bowen River tributary was identified as the major source of end‐of‐river suspended sediment export, yielding an average of 530 t km−2 yr−1 during the study period. Sediment trapping within a large reservoir (1.86 million ML) and the preferential transport of clays and fine silts downstream of the structure were also examined. The data reveal that the highest clay and fine silt loads—which are of most interest to environmental managers of the GBR—are not always sourced from areas that yield the largest total suspended sediment load (i.e., all size fractions). Our results demonstrate the importance of incorporating particle size into catchment sediment budget studies undertaken to inform management decisions to reduce downstream turbidity and sedimentation. Our data on sediment source, reservoir influence, and subcatchment and catchment yields will improve understandings of sediment dynamics in other tropical catchments, particularly those located in seasonally wet‐dry tropical savannah/semiarid climates. The influence of climatic variability (e.g., drought/wetter periods) on annual sediment loads within large seasonally dry tropical catchments is also demonstrated by our data.
Subsurface lateral preferential flow network revealed by time‐lapse ground‐penetrating radar in a hillslope
Authors: Guo Li , Chen Jin , Lin Henry
Published: October 2014

Subsurface lateral preferential flow (LPF) has been observed to contribute substantially to hillslope and catchment runoff. However, the complex nature of LPF and the lack of an appropriate investigation method have hindered direct LPF observation in the field. Thus, the initiation, persistence, and dynamics of LPF networks remain poorly understood. This study explored the application of time‐lapse ground‐penetrating radar (GPR) together with an artificial infiltration to shed light on the nature of LPF and its dynamics in a hillslope. Based on our enhanced field experimental setup and carefully refined GPR data postprocessing algorithms, we developed a new protocol to reconstruct LPF networks with centimeter resolution. This is the first time that a detailed LPF network and its dynamics have been revealed noninvasively along a hillslope. Real‐time soil water monitoring and field soil investigation confirmed the locations of LPF mapped by time‐lapse GPR surveys. Our results indicated the following: (1) Increased spatial variations of radar signals after infiltration suggested heterogeneous soil water changes within the studied soil, which reflected the generation and dynamics of LPF; (2) Two types of LPF networks were identified, the network at the location of soil permeability contrasts and that formed via a series of connected preferential flow paths; and (3) The formation and distribution of LPF networks were influenced by antecedent soil water condition. Overall, this study demonstrates clearly that carefully designed time‐lapse GPR surveys with enhanced data postprocessing offer a practical and nondestructive way of mapping LPF networks in the field, thereby providing a potentially significant enhancement in our ability to study complex subsurface flow processes across the landscape.
Observed interannual variability of zonal currents in the equatorial Indian Ocean thermocline and their relation to Indian Ocean Dipole
Authors: Zhang Dongxiao , McPhaden Michael J. , Lee Tong
Published: October 2014

Interannual variability of zonal currents in the eastern equatorial Indian Ocean thermocline is significantly correlated with sea surface temperature (SST) in the eastern pole of the Indian Ocean Dipole (IOD). This relationship is more significant than for zonal currents and the Dipole Mode Index, the latter of which measures zonal SST anomaly gradient. The variability of zonal currents in the thermocline is consistent with the variations of eastward pressure gradient force in the thermocline and the equatorward geostrophic thermocline flows associated with the shallow meridional overturning circulations in the eastern tropical Indian Ocean. Our analysis suggests a positive feedback between zonal currents in the thermocline and SST in the eastern pole of IOD. The combination of equatorial wind and off‐equatorial wind stress curls associated with SST anomalies in the eastern pole of the IOD drives interannual variability in equatorial zonal thermocline flows and its covariability with the shallow meridional overturning cells.
Charge balance and ionospheric potential dynamics in time‐dependent global electric circuit model
Authors: Jánský Jaroslav , Pasko Victor P.
Published: October 2014

We have developed a time‐dependent model of global electric circuit (GEC) in spherical coordinates. The model solves time‐dependent charge continuity equation coupled with Poisson's equation. An implicit time stepping is used to avoid a strict dielectric relaxation time step condition, and boundary conditions for Poisson's equation are implemented to allow accurate description of time evolution of the ionospheric potential. The concept of impulse response of GEC is introduced that allows effective representation of complex time dynamics of various physical quantities in the circuit using model results obtained for instantaneous deposition of a point charge. The more complex problems are then reconstructed using convolution and linearity principles. For a point charge instantaneously deposited at a typical thundercloud altitude the impulse response of the charge density shows induction of the same value and polarity charge at the ionospheric boundary, while charge of the same value but opposite sign is moving down logarithmically with time and neutralizes the source point charge on time scale corresponding to the dielectric relaxation time at altitude of the source point charge. The ionospheric potential is modified immediately with input of the source point charge based on free space solution of Poisson's equation. Then the ionospheric potential relaxes. It is shown that during formation of two main charge centers of the thundercloud, typically represented by a current dipole, the ionospheric potential can be determined from the difference of time integrals of two ionospheric potential impulse responses corresponding to charge locations at the opposite ends of the current dipole. For latitude‐ and longitude‐independent conductivity model, the total charge on the Earth is exactly zero at all times. During cloud‐to‐ground lightning discharge, the ionospheric potential changes instantaneously by a value proportional to the charge moment change produced by lightning and then relaxes to zero. For a typical charge moment change of 35Ckm and lightning frequency 10s−1, the ionospheric potential changes by 9.3kV; this value agrees well with the results presented by Rycroft et al. () and Rycroft and Odzimek ().
Wave normal angles of whistler mode chorus rising and falling tones
Authors: Taubenschuss Ulrich , Khotyaintsev Yuri V. , Santolík Ondrej , Vaivads Andris , Cully Christopher M. , Contel Olivier Le , Angelopoulos Vassilis
Published: October 2014

We present a study of wave normal angles (θk) of whistler mode chorus emission as observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) during the year 2008. The three inner THEMIS satellites THA, THD, and THE usually orbit Earth close to the dipole magnetic equator (±20°), covering a large range of L shells from the plasmasphere out to the magnetopause. Waveform measurements of electric and magnetic fields enable a detailed polarization analysis of chorus below 4 kHz. When displayed in a frequency‐θk histogram, four characteristic regions of occurrence are evident. They are separated by gaps at f/fc,e≈0.5 (f is the chorus frequency, fc,e is the local electron cyclotron frequency) and at θk∼40°. Below θk∼40°, the average value for θk is predominantly field aligned, but slightly increasing with frequency toward half of fc,e (θk up to 20°). Above half of fc,e, the average θk is again decreasing with frequency. Above θk∼40°, wave normal angles are usually close to the resonance cone angle. Furthermore, we present a detailed comparison of electric and magnetic fields of chorus rising and falling tones. Falling tones exhibit peaks in occurrence solely for θk>40° and are propagating close to the resonance cone angle. Nevertheless, when comparing rising tones to falling tones at θk>40°, the ratio of magnetic to electric field shows no significant differences. Thus, we conclude that falling tones are generated under similar conditions as rising tones, with common source regions close to the magnetic equatorial plane.
Deep crustal structure of an arc‐continent collision: Constraints from seismic traveltimes in central Taiwan and the Philippine Sea
Authors: Van Avendonk H. J. A. , Kuo‐Chen H. , McIntosh K. D. , Lavier L. L. , Okaya D. A. , Wu F. T. , Wang C. Y. , Lee C. S. , Liu C. S.
Published: October 2014

The collision of continental crust of the Eurasian Plate with the overriding Luzon Arc in central Taiwan has led to compression, uplift, and exhumation of rocks that were originally part of the Chinese rifted margin. Though the kinematics of the fold‐thrust belt on the west side of the orogen has been described in detail, the style of deformation in the lower crust beneath Taiwan is still not well understood. In addition, the fate of the Luzon Arc and Forearc in the collision is also not clear. Compressional wave arrival times from active‐source and earthquake seismic data from the Taiwan Integrated Geodynamic Research program constrain the seismic velocity structure of the lithosphere along transect T5, an east‐west corridor in central Taiwan. The results of our analysis indicate that the continental crust of the Eurasian margin forms a broad crustal root beneath central Taiwan, possibly with a thickness of 55 km. Compressional seismic velocities beneath the Central Range of Taiwan are as low as 5.5 km/s at 25 km depth, whereas P wave seismic velocities in the middle crust on the eastern flank of the Taiwan mountain belt average 6.5–7.0 km/s. This suggests that the incoming sediments and upper crust of the Eurasian Plate are buried to midcrustal depth in the western flank of the orogen before they are exhumed in the Central Range. To the east, the Luzon Arc and Forearc are deformed beneath the Coastal Range of central Taiwan. Fragments of the rifted margin of the South China Sea that were accreted in the early stages of the collision form a new backstop that controls the exhumation of Eurasian strata to the west in this evolving mountain belt.
Comparisons of emissivity observations from satellites and the ground at the CRCS Dunhuang Gobi site
Authors: Zhang Yong , Li Zhenglong , Li Jun
Published: October 2014

Two sets of field‐measured hyperspectral resolution infrared (IR) emissivity spectra were taken from the China Radiometric Calibration Sites (CRCS) Dunhuang site in China, with one representing daytime and the other representing nighttime. Comparisons of the two sets show that the daytime emissivity is smaller than the nighttime emissivity in almost the entire spectrum between 7.5 and 14 µm, strong field evidence to support emissivity diurnal variations, which have been reported in previous studies using satellite observations. These emissivities are used as a reference to evaluate three different emissivity products from the same site: the Atmospheric Infrared Sounder (AIRS) operational emissivity products, the Moderate Resolution Imaging Spectroradiometer (MODIS) operational emissivity products, and the University of Wisconsin‐Madison Hyperspectral Resolution IR emissivity (UWIREMIS) database. The AIRS emissivity does not agree as well with the field measurements when compared to that from MODIS and the UWIREMIS despite the fact that AIRS is hyperspectral; the likely cause for the disagreement is cloud contamination due to AIRS' large footprint. MODIS has the advantage of high spatial resolution and visible/near‐infrared channels to help the cloud mask and is therefore less affected by cloud contamination. The V4.1 MODIS emissivity agrees better with the field measurement than the UWIREMIS, while the V5 does not do as well. The UWIREMIS emissivity, on the other hand, has the advantage of hyperspectral resolution, which makes it more useful for applications. The temporal analysis of the three satellite‐based emissivity products is also presented.
Statistical emulation of streamflow projections from a distributed hydrological model: Application to CMIP3 and CMIP5 climate projections for British Columbia, Canada
Authors: Schnorbus Markus A. , Cannon Alex J.
Published: October 2014

A recent hydrological impacts study in British Columbia, Canada, used an ensemble of 23 climate change simulations to assess potential future changes in streamflow. These Coupled Model Intercomparison Project Phase 3 (CMIP3) simulations were statistically downscaled and used to drive the Variable Infiltration Capacity (VIC) hydrology model over several watersheds. Due to computational restrictions, the 23 member VIC ensemble is a subset of the full 136 member CMIP3 archive. Extending the VIC ensemble to cover the full range of uncertainty represented by CMIP3, and incorporating the latest generation CMIP5 ensembles, poses a considerable computing challenge. Thus, we extend the VIC ensemble using a computationally efficient statistical emulation model, which approximates the combined output of the two‐step process of statistical downscaling and hydrologic modeling, trained with the 23 member VIC ensemble. Regularized multiple linear regression links projected changes in monthly temperature and precipitation with projected changes in monthly streamflow over the Fraser and Peace River watersheds. Following validation, the statistical emulator is forced with the full suite of CMIP3 and CMIP5 climate change projections. The 23 member VIC ensemble has a smaller spread than the full ensemble; however, both ensembles provide the same consensus estimate of monthly streamflow change. Qualitatively, CMIP5 shows a similar streamflow response as CMIP3 for snow‐dominated hydrologic regimes. However, by end‐century, the CMIP5 worst‐case RCP8.5 has a larger impact than CMIP3 A2. This work also underscores the advantage of using emulation to rapidly identify those future extreme projections that may merit further study using more computationally demanding process‐based methods.
Regional patterns of interannual variability of catchment water balances across the continental U.S.: A Budyko framework
Authors: Carmona Alejandra M. , Sivapalan Murugesu , Yaeger Mary A. , Poveda Germán
Published: October 2014

Patterns of interannual variability of the annual water balance are explored using data from 190 MOPEX catchments across the continental U.S. This analysis has led to the derivation of a quantitative, dimensionless, Budyko‐type framework to characterize the observed interannual variability of annual water balances. The resulting model is expressed in terms of a humidity index that measures the competition between water and energy availability at the annual time scale, and a similarity parameter (α) that captures the net effects of other short‐term climate features and local landscape characteristics. This application of the model to the 190 study catchments revealed the existence of space‐time symmetry between spatial (between‐catchment) variability and general trends in the temporal (between‐year) variability of the annual water balances. The MOPEX study catchments were classified into eight similar catchment groups on the basis of magnitudes of the similarity parameter α. Interesting regional trends of α across the continental U.S. were brought out through identification of similarities between the spatial positions of the catchment groups with the mapping of distinctive ecoregions that implicitly take into account common climatic and vegetation characteristics. In this context, this study has introduced a deep sense of similarity that is evident in observed space‐time variability of water balances that also reflect the codependence and coevolution of climate and landscape properties.
Comparison of Two D−A Type Polymers with Each Being Fluorinated on D and A Unit for High Performance Solar Cells
Authors: Jo Jea Woong , Bae Seunghwan , Liu Feng , Russell Thomas P. , Jo Won Ho
Published: October 2014

For the purpose of investigating the effect of fluorination position on D−A type conjugated polymer on photophysical and photovoltaic properties, two types of fluorinated polymere are synthesized, HF with fluorination on electron‐donating unit and FH with fluorination on electron‐accepting unit. Compared to non‐fluorinated polymer, fluorinated polymers exhibit deeper HOMO energy levels without change of bandgap and stronger vibronic shoulder in UV−visible absorption, indicating that fluorination enhances intermolecular interaction. HF with fluorinated D unit exhibits well‐developed fibril network, low bimolecular recombination and high hole mobility, which lead a high PCE of 7.10% in conventional single‐junction solar cells, which is higher than the PCE (6.41%) of FH with fluorinated A unit. Therefore, this result demonstrates that fluorination on electron‐donating unit in D−A polymers could be a promising strategy for achieving high performance polymer solar cells.
The Effect of Large Compositional Inhomogeneities on the Performance of Organic Solar Cells: A Numerical Study
Authors: Bartesaghi Davide , Koster L. Jan Anton
Published: October 2014

The power conversion efficiency of solar cells based on a conjugated polymer (donor) and a fullerene derivative (acceptor) is very sensitive to the morphology of the active layer. One detrimental feature, which is often encountered in non‐optimal morphologies, is the occurrence of fullerene blobs in a finely mixed matrix containing both donor and acceptor material. Here, the effects of such fullerene blobs are studied in detail with a three‐dimensional drift‐diffusion model. It includes the effects of exciton diffusion and quenching; space‐charge; recombination, generation, drift and diffusion of charge carriers; and the injection/extraction of carriers at the contacts. The influence of blob size and shape, and matrix composition are quantified. The latter has the strongest effect on the overall efficiency, as most of the current is transported through the mixed phase. The total current flowing out of the solar cell can be split up in a part which comes from the interfacial region between the acceptor phase and the mixed phase, and a part that stems from the mixed phase itself. Depending on the bias voltage and the morphology, one or the other contribution is dominant. Finally, it is shown how both contributions can be computed with a simple one‐dimensional drift–diffusion simulator.