bluuebunny/crossref_metadata_2025 huggingface dataset:
A Numerical Simulation of Superplastic Double-Sided Roll Forming of Discal Parts
Authors: Jin Quan Lin
Published: March 2013

A numerical simulation of superplastic double-sided roll forming of aluminium alloy discal part is presented in this paper. The numerical results show strain and strain rate distribution, grain refinment, transformation from general hot forging to superplastic forming. The superplastic forming includes two stages: the small deformation stage is controlled by plastic deformation and grain refinment, and the large deformation stage superplastic deformation is main deformation mechanism.
Forging of Articles out of Aluminum Alloys under Superplastic Conditions – Difficulties and Methods of their Overcoming
Authors: Trifonov Vadim
Published: March 2013

The manuscript considers the possibility of using of superplastic deformation at hot forging of aluminum alloys. The analysis has been conducted concerning the use of different methods for imparting ultra-fine grain structure to aluminum alloys in terms of their workability. The deformation and heat processing for thermo-strengthened aluminum alloys has been proposed in which superplastic deformation is combined with hardening. The effect of such processing on mechanical and corrosion properties of aluminum alloys is shown. The model processing of a component is demonstrated at forging under superplasticity conditions often surpass the advantages obtained.
Microstructural Control of a Zn-22Al Alloy by Rolling Process
Authors: Manaka Toshiaki , Itoh Goroh , Loc Nguyen The , Motohashi Yoshinobu , Sakuma Takaaki
Published: March 2013

The Zn-22Al alloy with fine-equi-axed has been well known as a typical superplastic metallic material [1]. In the present study, The Zn-22Al alloy ingot of 20mm thickness was homogenized, either air-cooled or water-quenched, and then hot-rolled to a thickness of 2mm. Microstractural observation, showed that in the air-cooled specimens lammellar microstructure was formed after homogenization, and become fragmented to fine-grained microstructure as the hot rolling process proceeded. In the water-quenched specimens, equi-axed fine-grained microstructure with grain size under 2.1μm was attained and maintained throughout the hot rolling process.
Recent Application of Superformed 5083 Aluminum Alloy in the Aerospace Industry
Authors: Barnes Anthony J. , Raman Hari , Lowerson Andrew , Edwards David
Published: March 2013

Traditionally the Aerospace Industry has, most often, selected heat treatable aluminum alloys for its sheet metal fairings, panels and skins. With the introduction of superplastic forming (SPF) in the late 70’s and early 80’s the initial applications of SPF aluminum utilized the heat treatable superplastic alloys that were available then (ie. 2004 and 7475). When superplastic 5083 alloy sheet became commercially available in the late 1980’s applications were focused on the ‘high end’ automobile and the European rail markets. More recently, the qualification of SP5083 to aerospace standards, combined with appropriate design criteria, has enabled an increasing number and variety of aerospace components to be Superformed from this non-heat treatable medium strength alloy. This presentation examines a number of recent aerospace applications of Superformed 5083; from contemporary tool designs through to finished components. The important attributes of both SPF design; the ability to create complex geometry, and the excellent post-formed characteristics of SP5083 that have created cost effective solutions to specific Aerospace Industry needs are illustrated. Future prospects for stronger 5000 series superplastic alloys are also discussed.
Superplastic Forming and Pressure Welding of Multilayer Cellular Structures
Authors: Safiullin Rinat V.
Published: March 2013

The paper describes the results of long-term investigations on the development of the technology of superplastic forming and pressure welding (SPF/PW) conducted at the Institute for Metals Superplasticity Problems, Russian Academy of Sciences for producing standard articles of aero-space engineering, such as hollow blades, wing and shell panels. The process of solid state joint formation in titanium alloy sheets during SPF was studied. Different investigation techniques were developed. The results of the mechanical and fatigue testing as well as non-destructive inspection of hollow blades are presented. The prospects of the development of the SPF/PW technology are considered and the latest results are discussed.
Microstructural Evaluation of Friction Stir Processed D2 Tool Steel
Authors: Nagaoka Toru , Watanabe Hiroyuki , Fukusumi Masao , Kitamura Yusuke , Mizuno Tadashi , Abe Genryu , Morisada Yoshiaki , Fujii Hidetoshi
Published: March 2013

Modification of AISI D2 tool steel was conducted by friction stir processing (FSP). Effects of tool rotational speed on microstructural evolution and mechanical properties were investigated. Though coarse primary carbides in the size of 10-50 m were observed before FSP, fine carbides smaller than 20 m and martensitic matrix with fine grains were obtained after FSP. High hardness of over 900 HV, higher than the hardness in conventional D2 tool steel, was achieved under the condition of moderate rotational speed.
High-Temperature Deformation of Magnesium ElektronTM 43
Authors: Carpenter Alexander J. , Barnes Anthony J. , Taleff Eric M.
Published: March 2013

Complex sheet metal components can be formed from lightweight aluminum and magnesium sheet alloys using superplastic forming technologies. Superplastic forming typically takes advantage of the high strain-rate sensitivity characteristic of grain-boundary-sliding (GBS) creep to obtain significant ductility at high temperatures. However, GBS creep requires fine-grained materials, which can be expensive and difficult to manufacture. An alternative is provided by materials that exhibit solute-drag (SD) creep, a mechanism that also produces elevated values of strain-rate sensitivity. SD creep typically operates at lower temperatures and faster strain rates than does GBS creep. Unlike GBS creep, solute-drag creep does not require a fine, stable grain size. Previous work by Boissière et al. suggested that the Mg-Y-Nd alloy, essentially WE43, deforms by SD creep at temperatures near 400°C. The present investigation examines both tensile and biaxial deformation behavior of ElektronTM 43 sheet, which has a composition similar to WE43, at temperatures ranging from 400 to 500°C. Data are presented that provide additional evidence for SD creep in Elektron 43 and demonstrate the remarkable degree of biaxial strain possible under this regime (>1000%). These results indicate an excellent potential for producing complex 3-D parts, via superplastic forming, using this particular heat-treatable Mg alloy.
Antigen-Specific Memory Regulatory CD4+Foxp3+ T Cells Control Memory Responses to Influenza Virus Infection
Authors: Brincks Erik L. , Roberts Alan D. , Cookenham Tres , Sell Stewart , Kohlmeier Jacob E. , Blackman Marcia A. , Woodland David L.
Published: March 2013

Regulatory CD4+Foxp3+ T cells (Tregs) are key regulators of inflammatory responses and control the magnitude of cellular immune responses to viral infections. However, little is known about how Tregs contribute to immune regulation during memory responses to previously encountered pathogens. In this study, we used MHC class II tetramers specific for the 311–325 peptide from influenza nucleoprotein (NP311–325/IAb) to track the Ag-specific Treg response to primary and secondary influenza virus infections. During secondary infections, Ag-specific memory Tregs showed accelerated accumulation in the lung-draining lymph node and lung parenchyma relative to a primary infection. Memory Tregs effectively controlled the in vitro proliferation of memory CD8+ cells in an Ag-specific fashion that was MHC class II dependent. When memory Tregs were depleted before secondary infection, the magnitude of the Ag-specific memory CD8+ T cell response was increased, as was pulmonary inflammation and airway cytokine/chemokine expression. Replacement of memory Tregs with naive Tregs failed to restore the regulation of the memory CD8 T cell response during secondary infection. Together, these data demonstrate the existence of a previously undescribed population of Ag-specific memory Tregs that shape the cellular immune response to secondary influenza virus challenges and offer an additional parameter to consider when determining the efficacy of vaccinations.
Practical Theology as part of the landscape of Social Sciences and Humanities – A transversal perspective
Authors: Müller Julian C.
Published: March 2013

At the University of Pretoria the author, a practical theologian, experiences a fruitful soil for the development of an interdisciplinary process. He referred to concrete examples of cooperation, but used the article to reflect on best practices for the interdisciplinary dialogue. He came to the conclusion that it probably made more sense to talk of Practical-theological alternatives rather than to describe the subject in a single fixed manner of understanding and action. Our goal should rather be to open up the boundaries between Practical Theology, Human, Social and Natural Sciences.
An Early Warning System to Predict Speculative House Price Bubbles
Authors: Dreger Christian , Kholodilin Konstantin A.
Published: March 2013

In this paper, the authors construct country-specific chronologies of the house price bubbles for 12 OECD countries over the period 1969:Q1–2009:Q4. These chronologies are obtained using a combination of a fundamental approach and a filter approach. The resulting speculative bubble chronology is the one which provides the highest concordance between these two techniques. In addition, the authors suggest an early warning system based on three alternative approaches: A signalling approach, a logit model, and a probit model. It is shown that the latter two models allow much more accurate predictions of house price bubbles than the signalling approach. Furthermore, the predictive accuracy of the logit and probit models is high enough to make them useful in forecasting future speculative bubbles in housing market. Thus, this method can be used by the policymakers in their attempts to quickly detect house price bubbles and attenuate their devastating effects on the domestic and world economy.
Programa de Reducción del Estrés Basado en la Atención Plena: Un estudio exploratorio de su aplicación en un Hospital Público semi-rural del Sur de Chile
Authors: Brito Pons Gonzalo
Published: March 2013

La Meditación de Atención Plena proveniente de la tradición budista ha sido aplicada como herramienta preventiva y terapéutica en hospitales y clínicas por 30 años en occidente, siendo aun prácticamente desconocida en nuestro país. Este artículo presenta el Programa de Reducción del Estrés Basado en la Atención Plena como alternativa preventiva y terapéutica para el incremento del bienestar psicológico, alivio del estrés, y disminución de síntomas depresivos y ansiosos. Se describe la implementación de un programa piloto en el Hospital de Santa Bárbara (8va Región, Chile) y se presentarán los resultados de las evaluaciones pre-post de síntomas depresivos y ansiosos de los participantes. Finalmente se discuten las potencialidades de la réplica del programa en establecimientos de salud pública del país.
Sobre locura y emigración en el mundo globalizado
Authors: Cuestas Fedra
Published: March 2013

Este artículo presenta una discusión en torno a los desarrollos teóricos que sustentan la descripción de un nuevo Síndrome - el Síndrome de Ulises, también llamado Síndrome del Inmigrante con Estrés Crónico y Múltiple - detectado en inmigrantes de origen extracomunitario. Los criterios diagnósticos, que conducen al reconocimiento de este síndrome, han sido difundidos con el apoyo del Parlamento Europeo. La importancia dada por este Parlamento, a una problemática que afecta a ciudadanos no europeos, plantea una indagación sobre los fines que ella persigue.
Lo rural y la ruralidad en América Latina: categorías conceptuales en debate
Authors: Romero Cabrera Juan
Published: March 2013

Este artículo analiza la trayectoria conceptual rural - ruralidad, planteando el debate acerca del enfoque de la nueva ruralidad. La dinámica presente del mercado de empleo, de las cadenas agroalimentarias globales, los procesos demográficos impactando en la estructura de la familia rural, y la configuración de tejidos urbanos en los territorios rurales plantea nuevas interrelaciones entre lo urbano y lo rural. La complejización de la sociedad rural latinoamericana demanda una aplicación epistemológica cuidadosa del enfoque de la nueva ruralidad, dado que no tiene el mismo grado de validez para todas las regiones.
Propiedades psicométricas de la Escala de Bienestar Psicológico y estructura factorial en universitarios chilenos
Authors: Veliz-Burgos Alex
Published: March 2013

El estudio analiza las propiedades psicométricas y la estructura factorial de la Escala de Bienestar Psicológico de Ryff (1989) adaptada por van Dierendonck (2004). Se aplicó la escala a una muestra de 691 universitarios chilenos, con una media de 21.4 años (DT  2.6 años). La confiabilidad más alta de las subescalas es Autoaceptación (.79) y la más baja Propósito en la Vida (.54). El análisis factorial confirmatorio muestra un RMSEA de .068 considerado aceptable, un valor CFI igual a .95, un valor de NNFI .94 y un SRMR con un valor de .060. Se concluye que el modelo tendría un ajuste adecuado, lo que permitiría su uso en la población universitaria chilena.
El Laboratorio de los Conflictos de la Azienda Sanitaria Locale 3 Genovesa. Un servicio público a sostén de la parentalidad en la separación conyugal
Authors: Cavanna Donatella , Finzi Daria , Piermari Antonella , Spadacini Anna
Published: March 2013

La separación conyugal es una experiencia frecuente en la vida de muchas familias. Implica el fracaso de un proyecto de la vida en conjunto y una experiencia de pérdida que puede producir comportamientos sintomáticos y dinámicas relacionales disfuncionales. Estos efectos negativos, especialmente en niños, se atribuyen a la conflictividad entre  los padres y a su mayor o menor capacidad de interrogarse acerca del impacto de su desacuerdo sobre el estado emocional de los niños. El conocimiento de los posibles efectos de una separación matrimonial conflictiva respecto del bienestar psicológico de los niños ha aumentado la demanda de mediación familiar, facilitando que los padres vuelvan a asumir sus responsabilidades parentales. Este artículo  presenta la actividad de un servicio italiano de mediación familiar, que interviene con parejas con un nivel de conflicto intenso, con el fin de favorecer el volver a apropiarse de una modalidad de gestión conjunta de los niños. Se presenta un perfil de los usuarios, en relación al acuerdo, sea o no común, de contactarse con el servicio, y en relación a la tipología del enviante y a la tipología de separación, según la ley italiana.
La Dimensión Cualitativa en el Sistema de Postulación al Fondo Solidario de Vivienda I
Authors: Naranjo Carolina , Purcell Juan
Published: March 2013

La presente investigación participativa fue realizada por un equipo transdisciplinario de arquitectura y psicología, que se propuso crear un modelo habitacional de acuerdo a las necesidades y anhelos de un grupo de 30 familias, postulantes al Fondo Solidario de Vivienda I en la comuna de Valparaíso, Chile. La metodología cualitativa utilizada, permitió incorporar los hallazgos del estudio psicosocial, en el desarrollo del diseño del modelo habitacional. Los resultados muestran por una parte el anhelo de conservar la identidad familiar y pertenencia a la propia red de apoyo social y por otra parte, revelan la falta de límites familiares y espaciales, bajas expectativas de logro y dificultades para sostener la participación comunitaria.
Relación entre liderazgo educativo y desempeño escolar: Revisión de la investigación en Chile
Authors: Horn Kupfer Andrea , Marfán Sánchez Javiera
Published: March 2013

El presente trabajo da cuenta de 14 estudios realizados en Chile con base empírica que rescatan la importancia del liderazgo educativo en el logro de buenos resultados escolares. Estos estu- dios son producto de una revisión bibliográfica de publicaciones del año 2000 en adelante. El objetivo del artículo es presentar los alcances de la investigación empírica que se ha desarrolla- do, sobre la relación entre liderazgo escolar y resultados de aprendizaje en el sistema escolar chileno. De manera sintética se expone la evidencia que se ha ido desarrollando durante los últimos 10 años de investigación, paralelamente, se presentan las metodologías utilizadas por los investigadores para poder plantear sus resultados y conclusiones. Finalmente, se ponen en conversación los avances y falencias que muestra la investigación desarrollada hasta la fecha en el tema, así como su sintonía con los avances de la investigación a nivel internacional.
Convective cells of internal gravity waves in the earth's atmosphere with finite temperature gradient
Authors: Onishchenko O. , Pokhotelov O. , Fedun V.
Published: March 2013

Abstract. In this paper, we have investigated vortex structures (e.g. convective cells) of internal gravity waves (IGWs) in the earth's atmosphere with a finite vertical temperature gradient. A closed system of nonlinear equations for these waves and the condition for existence of solitary convective cells are obtained. In the atmosphere layers where the temperature decreases with height, the presence of IGW convective cells is shown. The typical parameters of such structures in the earth's atmosphere are discussed.
Inferring past land use-induced changes in surface albedo from satellite observations: a useful tool to evaluate model simulations
Authors: Boisier J. P. , de Noblet-Ducoudré N. , Ciais P.
Published: March 2013

Abstract. Regional cooling resulting from increases in surface albedo has been identified in several studies as the main biogeophysical effect of past land use-induced land cover changes (LCC) on climate. However, the amplitude of this effect remains quite uncertain due to, among other factors, (a) uncertainties in the extent of historical LCC and, (b) differences in the way various models simulate surface albedo and more specifically its dependency on vegetation type and snow cover. We derived monthly albedo climatologies for croplands and four other land cover types from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. We then reconstructed the changes in surface albedo between preindustrial times and present-day by combining these climatologies with the land cover maps of 1870 and 1992 used by seven land surface models (LSMs) in the context of the LUCID ("Land Use and Climate: identification of robust Impacts") intercomparison project. These reconstructions show surface albedo increases larger than 10% (absolute) in winter, and larger than 2% in summer between 1870 and 1992 over areas that experienced intense deforestation in the northern temperate regions. The historical surface albedo changes estimated with MODIS data were then compared to those simulated by the various climate models participating in LUCID. The inter-model mean albedo response to LCC shows a similar spatial and seasonal pattern to the one resulting from the MODIS-based reconstructions, that is, larger albedo increases in winter than in summer, driven by the presence of snow. However, individual models show significant differences between the simulated albedo changes and the corresponding reconstructions, despite the fact that land cover change maps are the same. Our analyses suggest that the primary reason for those discrepancies is how LSMs parameterize albedo. Another reason, of secondary importance, results from differences in their simulated snow extent. Our methodology is a useful tool not only to infer observations-based historical changes in land surface variables impacted by LCC, but also to point out deficiencies of the models. We therefore suggest that it could be more widely developed and used in conjunction with other tools in order to evaluate LSMs.
A high-resolution and harmonized model approach for reconstructing and analysing historic land changes in Europe
Authors: Fuchs R. , Herold M. , Verburg P. H. , Clevers J. G. P. W.
Published: March 2013

Abstract. Human-induced land use changes are nowadays the second largest contributor to atmospheric carbon dioxide after fossil fuel combustion. Existing historic land change reconstructions on the European scale do not sufficiently meet the requirements of greenhouse gas (GHG) and climate assessments, due to insufficient spatial and thematic detail and the consideration of various land change types. This paper investigates if the combination of different data sources, more detailed modelling techniques, and the integration of land conversion types allow us to create accurate, high-resolution historic land change data for Europe suited for the needs of GHG and climate assessments. We validated our reconstruction with historic aerial photographs from 1950 and 1990 for 73 sample sites across Europe and compared it with other land reconstructions like Klein Goldewijk et al. (2010, 2011), Ramankutty and Foley (1999), Pongratz et al. (2008) and Hurtt et al. (2006). The results indicate that almost 700 000 km2 (15.5%) of land cover in Europe has changed over the period 1950–2010, an area similar to France. In Southern Europe the relative amount was almost 3.5% higher than average (19%). Based on the results the specific types of conversion, hot-spots of change and their relation to political decisions and socio-economic transitions were studied. The analysis indicates that the main drivers of land change over the studied period were urbanization, the reforestation program resulting from the timber shortage after the Second World War, the fall of the Iron Curtain, the Common Agricultural Policy and accompanying afforestation actions of the EU. Compared to existing land cover reconstructions, the new method considers the harmonization of different datasets by achieving a high spatial resolution and regional detail with a full coverage of different land categories. These characteristics allow the data to be used to support and improve ongoing GHG inventories and climate research.
Trace metal/Ca ratios in benthic foraminifera: the potential to reconstruct past variations in temperature and hypoxia in shelf regions
Authors: Groeneveld J. , Filipsson H. L.
Published: March 2013

Abstract. Shelf and coastal regions are exceptionally important for many countries as they provide the main habitat for many economically important fish and shellfish species. With ongoing global warming and human-induced eutrophication the shelf regions are especially affected, resulting in increased temperatures and stratification as well as oxygen depletion of the bottom waters. In order to be able to predict the magnitude of these changes in the future it is necessary to study how they varied in the past. Commonly used foraminiferal climate and environmental proxies, e.g. stable isotopes and trace metal/Ca ratios, which are applied in open-ocean settings are not necessarily applicable in shelf regions, either as faunas are completely different or as conditions change a-typical compared to the open-ocean. In this study we explore the use of Mg/Ca as paleothermometer and Mn/Ca as a potential proxy for changing dissolved oxygen conditions on the benthic foraminifera Bulimina marginata and Globobulimina turgida. Living specimens were collected from the Skagerrak and the Gullmar Fjord (SW-Sweden); the latter is hypoxic for several months a year. As the specimens were alive when collected it can be excluded that any diagenetic coatings have affected the trace metal/Ca ratios. The Mg/Ca ratios are similar to previously published values from the literature but display much larger variation than would be expected from the annual temperature change of less than 2 °C. An additional impact of the difference in the carbonate ion saturation state between the Skagerrak and the Gullmar Fjord could explain the results. Mn/Ca ratios on Globobulimina turgida potentially record variations in dissolved oxygen of the habitat where the foraminifera calcify. Samples from the Skagerrak display increased Mn/Ca in specimens which lived deeper in the sediment than those that lived near the surface. Globobulimina turgida samples from the lower oxygen Gullmar Fjord showed significantly increased Mn/Ca, being highest when dissolved oxygen was at a minimum. Our study suggests that trace metal/Ca ratios in benthic foraminifera from shelf regions have the potential to record past variations in bottom water temperature and dissolved oxygen concentrations but care needs to be taken to constrain the carbonate system.
Technical Note: Highly precise quantitative measurements of total dissolved inorganic carbon from small amounts of seawater using a common gas chromatographic system: an alternative method compared to established detection systems
Authors: Hansen T. , Gardeler B. , Matthiessen B.
Published: March 2013

Abstract. Total dissolved inorganic carbon (CT) is one of the most frequently measured parameters in order to calculate the partial pressure of carbon dioxide in seawater. Its measurement has become increasingly important because of the rising interest in the biological effects of acidification. The coulometric- and infrared detection methods are favoured to precisely quantify CT. However, these methods were not validated for CT samples from acidification experiments investigating biological responses to manipulated partial pressure of carbon dioxide (pCO2), which need an extended CT measurement range (~1250–2400 μmol kg−1) compared to natural open ocean seawater samples (~1950–2200 μmol kg−1). Additionally, the requirement of total sample amounts between 0.25–1 L seawater in the coulometric- and infrared detection methods exclude their use for experiments working with smaller volumes. Precise CT analytics also become difficult with high amounts of biomass (e.g. phytoplankton cultures) or even impossible in the presence of planktonic calcifiers without sample pre-filtration. However, filtration can alter CT concentration through gas exchange. Addressing these problems, we present precise quantification of CT using a small, basic and inexpensive gas chromatograph as a highly sensitive CT-analyzer. Our technique is able to provide a measurement precision of ± 3.7 μmol kg−1 and an accuracy of ± 1.2 μmol kg−1 in a CT range typically applied in acidification experiments. It requires sample sizes of only 200 μL taken from 10 mL pre-filtered samples or from a 10 mL sub-sampled seawater reference (Dickson standard). Our method is simple, reliable and with low cumulative analytical costs. Hence, it is potentially attractive for all scientists experimentally manipulating the seawater carbonate system.
A new automatic method for estimating the peak auroral emission height from all-sky camera images
Authors: Whiter D. K. , Gustavsson B. , Partamies N. , Sangalli L.
Published: March 2013

Abstract. This paper presents a new fully automatic method for quickly finding the average peak emission height of a single auroral structure from a pair of all-sky camera images with overlapping fields of view. The peak emission height of the aurora must be estimated in order to calculate several other important parameters, such as horizontal spatial scales, optical flow velocities, and ionospheric electric fields. In most cases the height is not measured, but a value is assumed, often about 110 km. It is unclear how accurate this assumption is. A future statistical study of the auroral height in which the method presented here will be applied to many years of observations will lead to more accurate assumptions of the height with quantitative error estimates, and therefore more accurate estimates of parameters derived using these assumed auroral heights. In the present work the performance of the new method is compared to another recent automatic method. It is found that the new method measures the peak emission height regardless of the shape of the volume emission rate profile, unlike the other recent method. However, the new method is less suitable than the other method for analysis of very wide auroral arcs (>30 km) or for aurora in the magnetic zenith of one of the images.
Geomorphology-based index for detecting minimal flood stages in arid alluvial streams
Authors: Shamir E. , Ben-Moshe L. , Ronen A. , Grodek T. , Enzel Y. , Georgakakos K. P. , Morin E.
Published: March 2013

Abstract. Identification of a geomorphic index to represent lower thresholds for minor flows in ephemeral, alluvial streams in arid environments is an essential step as a precursor for reliable flash flood hazard estimations and establishing flood warning systems. An index, termed Alluvial wadi Flood Incipient Geomorphologic Index (AFIG), is presented. Analysis of data from an extensive field survey in the arid ephemeral streams in southern and eastern Israel was conducted to investigate the AFIG and the control over its value across the region. During the survey we identified distinguishable flow marks in the lower parts of streams' banks, such as niches, vegetation line, and change in bank material, which are indicative of low flows. The cross-sectional characteristics of the AFIG were studied in relationship with contributing drainage basin characteristics such as lithology, topography, and precipitation. Drainage area and hardness of the exposed lithology (presented as a basin-wide index) are the preferred descriptors to be used in estimating a specific AFIG in unsurveyed sites. Analyses of discharge records from seven hydrometric stations indicate that the recurrence interval of the determined AFIG is equal to or more frequent than 0.5 yr.
Evaluation of seismo-electric anomalies using magnetic data in Taiwan
Authors: Chen C. H. , Hsu H. L. , Wen S. , Yeh T. K. , Chang F. Y. , Wang C. H. , Liu J. Y. , Sun Y. Y. , Hattori K. , Yen H. Y. , Han P.
Published: March 2013

Abstract. The Parkinson vectors derived from 3-component geomagnetic data via the magnetic transfer function are discussed with respect to epicentre locations and hypocentre depths of 16 earthquakes (M ≥ 5.5) in Taiwan during a period of 2002–2005. To find out whether electric conductivity changes would happen particularly in the seismoactive depth ranges, i.e. in the vicinity of the earthquake foci, the frequency dependent penetration depth of the electromagnetic waves (skin effect) is taken into account. The background distributions involving the general conductivity structure and the coast effect at 20 particular depths are constructed using the Parkinson vectors during the entire study period. The background distributions are subtracted from the time-varying monitor distributions, which are computed using the Parkinson vectors within the 15-day moving window, to remove responses of the coast effect and underlying conductivity structure. Anomalous depth sections are identified by deviating distributions and agree with the hypocentre depths of 15 thrust and/or strike-slip earthquakes with only one exception of a normal fault event.
Towards an integrated forecasting system for fisheries on habitat-bound stocks
Authors: Christensen A. , Butenschön M. , Gürkan Z. , Allen I. J.
Published: March 2013

Abstract. First results of a coupled modelling and forecasting system for fisheries on habitat-bound stocks are being presented. The system consists currently of three mathematically, fundamentally different model subsystems coupled offline: POLCOMS providing the physical environment implemented in the domain of the north-west European shelf, the SPAM model which describes sandeel stocks in the North Sea, and the third component, the SLAM model, which connects POLCOMS and SPAM by computing the physical–biological interaction. Our major experience by the coupling model subsystems is that well-defined and generic model interfaces are very important for a successful and extendable coupled model framework. The integrated approach, simulating ecosystem dynamics from physics to fish, allows for analysis of the pathways in the ecosystem to investigate the propagation of changes in the ocean climate and to quantify the impacts on the higher trophic level, in this case the sandeel population, demonstrated here on the basis of hindcast data. The coupled forecasting system is tested for some typical scientific questions appearing in spatial fish stock management and marine spatial planning, including determination of local and basin-scale maximum sustainable yield, stock connectivity and source/sink structure. Our presented simulations indicate that sandeel stocks are currently exploited close to the maximum sustainable yield, even though periodic overfishing seems to have occurred, but large uncertainty is associated with determining stock maximum sustainable yield due to stock inherent dynamics and climatic variability. Our statistical ensemble simulations indicates that the predictive horizon set by climate interannual variability is 2–6 yr, after which only an asymptotic probability distribution of stock properties, like biomass, are predictable.
Post-processing scheme for modelling the lithospheric magnetic field
Authors: Lesur V. , Rother M. , Vervelidou F. , Hamoudi M. , Thébault E.
Published: March 2013

Abstract. We investigated how the noise in satellite magnetic data affects magnetic lithospheric field models derived from these data in the special case where this noise is correlated along satellite orbit tracks. For this we describe the satellite data noise as a perturbation magnetic field scaled independently for each orbit, where the scaling factor is a random variable, normally distributed with zero mean. Under this assumption, we have been able to derive a model for errors in lithospheric models generated by the correlated satellite data noise. Unless the perturbation field is known, estimating the noise in the lithospheric field model is a non-linear inverse problem. We therefore proposed an iterative post-processing technique to estimate both the lithospheric field model and its associated noise model. The technique has been successfully applied to derive a lithospheric field model from CHAMP satellite data up to spherical harmonic degree 120. The model is in agreement with other existing models. The technique can, in principle, be extended to all sorts of potential field data with "along-track" correlated errors.
Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011
Authors: Gardelle J. , Berthier E. , Arnaud Y. , Kääb A.
Published: March 2013

Abstract. The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To overcome the lack of region-wide mass balance data, we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo-imagery for 8 sites spread from Pamir to eastern Himalaya. The region-wide glacier mass balances were contrasted during the last decade, with moderate mass losses in eastern and central Himalaya (−0.21 ± 0.10 m yr−1 w.e. to −0.29 ± 0.09 m yr−1 w.e.) and larger losses in western Himalaya (−0.41 ± 0.11 m yr−1 w.e.). Recently reported slight mass gain of glaciers in central Karakoram is confirmed for a larger area (+0.10 ± 0.19 m yr−1 w.e.) and, new, also observed for glaciers in western Pamir (+0.14 ± 0.10 m yr−1 w.e.). We propose that the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers is estimated at −0.12 ± 0.06 m yr−1 w.e. In contrast to Indus, the relative glacier imbalance contribution to Brahmaputra and Ganges discharges is higher than previously modeled glacier seasonal contribution.
Assessment of Corneal Topography Indices after Collagen Crosslinking for Keratoconus
Authors: Hassan Ziad , Szalai Eszter , Módis László , Berta András , Németh Gábor
Published: March 2013

Purpose

Riboflavin UVA (collagen crosslinking [CXL]) treatment for keratoconus is a method for stabilizing or improving corneal properties. Our aim was to evaluate changes in corneal topography indices after CXL.

Methods

A total of 38 eyes of 25 patients (mean age 29.36 ± 9.7 years) were treated with CXL technique. The follow-up period was 36 months. Slit-lamp examination, visual acuity tests, and pachymetry measurements were performed; in order to obtain the following numerical data, corneal topography (TMS-4; Tomey) was used: simulated keratometry (K1, K2), CYL (cylinder value), SAI (surface asymmetry index), IAI (irregular astigmatism index), SRI (surface regulatory index), ACP (average corneal power), and CEI (corneal eccentricity index). Treatments were performed with In-Pro CCL-Lix (Germany) equipment.

Results

The values of mean K1 (p = 0.82), cylinder (p = 0.73), SAI (p = 0.99), IAI (p = 0.82), SRI (p = 0.73), ACP (p = 0.73), K2 (p = 0.8), and CEI (p = 0.99) showed no significant changes at the end of the examination period. Uncorrected visual acuity remained unchanged (p = 0.32). However, best-corrected visual acuity changed from 0.21 ± 0.17 to 0.12 ± 0.11 in logMAR scale, but this deviation was not considered significant (p = 0.08). No change was observed in intraocular pressure (p = 0.79). Cornea remained clear and during follow-up period no corneal thinning was observed (p = 0.78).

Conclusions

Our results suggest that corneal collagen CXL can be a successful treatment at certain stages of keratoconus, offering a way to stop progression in keratometric indices.
Preservative-free Treatment in Glaucoma: Who, when, and why?
Authors: Stalmans Ingeborg , Mégevand Gordana Sunaric , Cordeiro M. Francesca , Hommer Anton , Rossetti Luca , Goñi Francisco , Heijl Anders , Bron Alain
Published: March 2013

Purpose

To review and summarize the available literature on the effect of preservatives on the eye, to provide practical guidance for the clinical assessment of the ocular surface in glaucoma patients, and to define patient populations that might benefit from preservative-free topical intraocular pressure (IOP)–lowering agents.

Methods

This manuscript is based on a combination of a literature review on preservatives and the eye and expert opinion from glaucoma specialists with an interest in ocular surface disease.

Results

There is an increasingly recognized association between eyedrop preservatives and ocular surface disease. Preservative-free therapy is now available for a wide range of active compounds, although there are still some misconceptions regarding their appropriate use. For patients treated topically for glaucoma or ocular hypertension, a rough estimate could be that 20% may need treatment with topical IOP-reducing agents that are free from preservatives.

Conclusions

This review provides an up-to-date account of the literature regarding preservatives and the eye, as well as suggestions and recommendations on to when to use preservative-free antiglaucoma treatment.
Indications and Efficacy of Fiberoptic Bronchoscopy in the ICU: Have They Changed Since Its Introduction in Clinical Practice?
Authors: Álvarez-Maldonado Pablo , Núñez-Pérez Redondo Carlos , Casillas-Enríquez José D. , Navarro-Reynoso Francisco , Cicero-Sabido Raúl
Published: March 2013

Purpose. We describe characteristics, utility, and safety of fiberoptic bronchoscopy (FOB) in an intensive care unit (ICU). Methods. Prospective and descriptive cohort of patients admitted to a respiratory ICU from March 2010 to June 2012. Results. A total of 102 FOBs were performed in 84 patients among 580 patients that were admitted to the ICU. Mean age was 48±17 years. FOB was useful in 65% of diagnostic procedures and 83% of therapeutic procedures, with an overall utility of 75%. Indications and utility according to indication were pneumonia in 31 cases, utility of 52%; percutaneous tracheostomy guidance in 26 cases, utility of 100%; atelectasis in 25 cases, utility of 76%; airway exploration in 16 cases, utility of 75%; hemoptysis in two cases, utility of 100%; and difficult airway intubation in two cases, utility of 100%. A decrease in oxygen saturation (SpO2) of >5% during FOB was present in 65% of cases, and other minor complications were present in 3.9% of cases. Conclusions. Reasons for performing FOB in the ICU have remained relatively stable over time with the exception of the addition of percutaneous tracheostomy guidance. Our series documents current indications and also the utility and safety of this procedure.
Optimal Positioning for ERCP: Efficacy and Safety of ERCP in Prone versus Left Lateral Decubitus Position
Authors: Batheja Mashal , Harrison M. Edwyn , Das Ananya , Engel Rodney , Crowell Michael
Published: March 2013

Background. ERCP is customarily performed with the patient in prone position. For patients intolerant of prone positioning, ERCP in left lateral decubitus (LLD) position offers a potential alternative. Aims. To compare efficacy and safety of ERCP in the LLD position versus prone position. Methods. Consecutive ERCP reports from August 2009 to October 2010 at Mayo Clinic Arizona were reviewed. Inclusion criteria. Age > 18 years, native papilla, and biliary indication. Primary outcome measure. Bile duct cannulation rate. Secondary outcomes. Times to ampullary localization and bile duct cannulation and complication rate. Results. ERCPs reviewed from 59 patients in two positions: 39 prone and 20 LLD. Cannulation Rate. 100% prone versus 90% in LLD (P=0.11). Median (IRQ) times. (1) Ampullary localization: 90 sec (70–110) prone versus 100 sec (80–118) (P=0.16); (2) bile duct cannulation: 140 sec (45–350) prone versus 165 sec (55–418) LLD (P=0.54). Complications. No periprocedure; postprocedure 4 (10%) prone versus 3 (15%) LLD (P=0.65). Conclusion. ERCP performed in LLD position allowed deep bile duct cannulation in 90% of patients without significantly increased procedural times or rate of complications as compared to prone position.
Perceptions of hospital admission in patients with cystic fibrosis
Authors: Visse Merel , Abma Tineke , Van den Oever Hetty , Prins Yvonne , Gulmans Vincent
Published: March 2013

Aims and objectives: This paper is a report of a study of experiences of people with Cystic Fibrosis (CF) with their hospital admission. It evaluates how they perceive their treatment and care and the impact on their social life (school or work). Background: In The Netherlands, people with CF are hospitalized in seven CF centers. In general, hospitalization may raise several challenges concerning the patient’s psychosocial well-being, before, during and after the admission. The admission of people with CF is complicated, because of segregated treatment and care that aims to prevent hospital-based cross-infection. Design: This article reports on a qualitative study. Methods: Data were collected during 2009 and 2010. Nineteen people with CF admitted for more than 5 days in one of the seven Dutch CF-centres participated. Results and conclusions: The findings are organized into five contexts with subthemes: Before admission & Arrival (1); Treatment & Care (2); Room & Stay (3); Discharge (4); Social & Societal context (5). The findings show that patients express a need for enhancing the quality of some treatments, like intravenous injections and patients express normative expectations of professionals that directly relate to their psychosocial well-being, e.g. they want to be ‘seen’ and treated as human beings and not solely as patients. They desire segregation policies to be consistent, whilst simultaneously they prefer flexible segregation guidelines. In general, respondents are satisfied with hospital facilities. The study reports on challenges concerning continuation of school and work during the admission. The paper is relevant to every hospital where people are being nursed in isolation.
Authentic Argumentation With Prospective Secondary Teachers: The Case of 0.999…
Authors: Conner AnnaMarie
Published: March 2013

Engaging prospective secondary teachers in mathematical argumentation is important, so that they can begin to learn to engage their own students in creating and critiquing arguments. Often, when we attempt to engage prospective secondary teachers in argumentation around topics from secondary mathematics classes, the argumentation is not authentic, as they believe they already know the answers. I suggest that there are problems related to the secondary curriculum around which we can engage students in authentic argumentation, and I propose one of them is whether 0.999… = 1. Purposefully engaging and supporting students in discussing this problem, and others like it, can lead to productive discussions that go beyond the answer to the question, including, for instance, what counts as evidence in mathematics.
A Feedback Linearization Based Nonlinear Control Approach for Variable Speed Wind Turbines
Authors: Fekih Afef , Shehri Abdullah Al
Published: March 2013

This paper describes the design and implementation of a nonlinear control strategy for the control of the shaft speed of wind turbine systems. The proposed approach is based on input-output linearization techniques. Because wind turbine systems are highly nonlinear, feedback linearization constitutes a suitable optimal control design for those systems. Further, Electromechanical systems in general are good candidates for nonlinear control applications because the nonlinearities, being modeled on the basis of physical principles, are often significant and exactly known.
The underlying design objective is to endow the wind turbine with high performance dynamics while maximizing power extraction when the wind turbine operates in the partial load regime. In addition to fulfilling the aforementioned control objectives, our control design aims to reduce the complexity of the control scheme, saving thereby the computation time of the control algorithm, which is an improvement over previous work found in the technical literature.
Application of the proposed approach to an induction generator based variable speed wind turbine has led to optimum operations and maximization of power extraction when the wind turbine operates in the partial load regime.