bluuebunny/crossref_metadata_2025 huggingface dataset:
De la lecture à l'usage de l'internet arabe
Authors: Stephan-Hachem Maud
Published: July 2013

Les ressources informationnelles en langue arabe disponibles sur la Toile peuvent elles répondre aux attentes des jeunes en matière d’information et de culture ? Pour décrire les pratiques culturelles des jeunes Libanais, notamment en matière de lecture et d’usage de l’internet, cette étude réalisée par Maud Stephan-Hachem se fonde sur les résultats d’une enquête auprès de jeunes étudiants. Elle se penche ensuite sur le type d’information, de sites, d’ouvrages numérisés dont disposent les jeunes qui ne lisent que l’arabe. Quels contenus leur propose-t-on et sous quelles formes ? L’offre numérique, tant scientifique que culturelle, est-elle facilement accessible, est-elle suffisamment attractive, dynamique, interactive, pour inciter à lire et s’informer en arabe ?
Filiations et affiliations entre génétique et clinique : la production de la différence
Authors: Giacobino Ariane , Ansermet François
Published: July 2013

Cet article aborde la problématique clinique de la filiation et de l’affiliation d’une part à partir de la détermination génétique et d’autre part à partir des processus de marquages environnementaux épigénétiques, en se centrant sur la question de la production de la variation interindividuelle et de sa transmission entre les générations. En effet, on peut voir la génétique comme nous réduisant à une entité codée, nous définissant comme issu de- et descendant de-, mais aussi, à la lumière des connaissances nouvelles sur les millions de variants de séquence ADN et leurs combinaisons, comme un imprédictible. Dans ce sens, les modulations chimiques du génome, par l’environnement, nous rapportent à être élément génétique instable, en constante évolution. De plus, ces modifications épigénétiques ont été démontrées transmissibles au travers de quelques générations, et font donc intervenir dans notre filiation, la transmission de ce que l’environnement nous fait devenir. Si à cela on ajoute la stochasticité, ou l’aléatoire de certains processus biologique, tous les éléments concordent pour nous penser comme fondamentalement, et génétiquement, imprévisibles.
La tyrannie du choix chez les jeunes aborigènes d'australie
Authors: Moïsseeff Marika
Published: July 2013

À partir d’un travail au long cours dans une communauté aborigène australienne, l’auteure tente de mettre en évidence la spécificité des problèmes auxquels sont confrontés les jeunes Aborigènes pour accéder à une identité d’adulte : dans un contexte de relations conflictuelles entre deux communautés posées comme ennemies, ils doivent démontrer clairement leur loyauté à la communauté la plus discriminée. Revendiquer haut et fort sa seule affiliation aborigène en endossant les stéréotypes véhiculés par les Blancs est une façon paradoxale de regagner du pouvoir dont les conséquences ne sont pas sans risques.
Repercusiones socioeconómicas y territoriales del modelo agroexportador argentino en la zona de Pigüé (Buenos Aires, Argentina) entre 1880 y 1930
Authors: Genchi Sibila A. , Fittipaldi Rosa A. , Rosell María Patricia
Published: July 2013

No disponible
Web Browsers Security Web-Lab
Authors: Serrhini Mohammed
Published: July 2013

One of the biggest created software is Web browser, today's almost is unique software used to access online for lot off electronic transactions services such as e-mail, e-banking, e-commerce, and e-learning etc... Hackers know that browsers are installed into all computers, smart phones, tablets , soon other devices such TV, Cars and others, they can be used to compromise all this devices, all browsers have enabled or disabled features that define theirs behaviors for executing good material and stopping malicious ones, unfortunately most of users are unwilling to setup this features correctly to enhance theirs safety, because many of them still do not understand even basic security concepts. This paper presents Web Browsers Security Web-Lab where student can practice and test online the real security threat that he was or could be exposed with his browser, we describe a two part for achieving this work, first an application launched at student side that will automatically detect all installed browsers and theirs features setting in his computer and based on the finding prepare to him an online tailored security awareness practicing work program and second Web-Lab platform where he can practice and test all security hole and risk if he browse the web with such enabled or disabled feature in his browser.
A Remote Engineering Lab for Collaborative Experimentation
Authors: Odeh Salaheddin , Ketaneh Eiman
Published: July 2013

Collaborative working is a fundamental feature of contemporary organizations and is increasingly being supported by technology. Its main goal is to enable each of the collaborating group members to bring and to contribute ideas and knowledge to the group and then to share it with them in order to combine it into a final result. In engineering education, concepts taught through lectures are often complemented by lab experimentation, through which students can observe phenomena that are often difficult to explain by written material. This contribution presents a collaborative working environment for remote experimentation, which allows two students or more to conduct remote experiments at the same time as a team. The lab can be accessed via Internet from any place and at any time, and enables the students to obtain an automated help by either a human tutor or a rule-based e-tutor.
BP-PID Control for Electro-hydraulic Proportional Position Servo System
Authors: Jianming Zheng , Min Xiao , Mingshun Yang , Yan Li , Lingfei Kong
Published: July 2013

The electro-hydraulic proportional position servo system is a kind of highly non-linear and time-varying system as well as parameter uncertainties. It is often difficult to achieve satisfactory control results with the traditional control methods. Considering that the adaptive neural network PID control method has the characteristics of online learning and adjustment PID control parameters adaptively, this paper puts forward to adopt BP-PID control method for the position servo control of electro-hydraulic proportional system. An online adaptive BP-PID controller is designed. The simulation model of the system is established based on Simulink platform. The step response and Sinusoidal tracking characteristics are researched for electro-hydraulic proportional position servo system by using traditional PID and BP-PID control algorithms through simulations and experiments. The results show that BP-PID has a strong ability of online learning and self-tuning PID parameters. Compared with the traditional PID control method, the BP-PID control has strong self-adaptability and robustness, and can significantly improve the step response speed and tracking control precision.
Design State Exploration applied to the development of a Remote Lab for Projectile Launch Experiments
Authors: Alves Gustavo R. , Marques Maria A. , Paiva Carlos , Nogueira Pedro , Guimarães Pedro , Couto Rubem , Cherem Laryssa , Borba Vitor , Ferreira Golberi S. , Koch Stefan , Pester Andreas
Published: July 2013

This paper describes the application of Design State Exploration techniques in the development of a remote lab for projectile motion experiments. The application was enabled by the existence of two independent teams: one composed of a series of internships that started first and another with two grantees that started a few months later. The paper presents evidence on how this approach provided gains in the development process conducted by the second team that benefited from design state exploration studies performed by the first team. This particular aspect is highlighted in relation to the work already presented in the 10th Remote Engineering and Virtual Instrumentation (REV) conference.
A Novel Algorithm of Fundamental Positive Sequence Voltage Detector under Unbalanced and Distorted Voltages
Authors: Zhiqiang Wang , Jing Bian , Yawei Wang , Guofeng Li
Published: July 2013

This paper presented a new algorithm for the performance improvement of fundamental positive sequence voltage extraction under unbalanced and distorted conditions. In this algorithm, an improved software phase-locked loop (SPLL) with a second order low-pass filter was proposed and analyzed, completely eliminating the phase detection errors of the unbalanced and distorted source voltages. The paper began with a description of the proposed fundamental positive sequence extraction method, and then a detailed analysis of the designed SPLL was introduced. The proposed algorithm improved the sinusoidal current control strategy of active power filter (APF) which was based on the classical power theories for obtaining an optimal extraction of the fundamental positive sequence current. To verify the feasibility of the algorithm in real-time applications, the simulation model was established in MATLAB-Simulink environment. Then, the algorithm was implemented in DSP using the TMS320F28335 development board. The results indicated that the proposed algorithm is feasible and effective, and it could be directly used in the practical applications.
Intelligent Control Strategy of Traffic Light at Urban Intersection
Authors: Han Qiang , Zhou Yong
Published: July 2013

Urban traffic is closely bound up with daily life, and traffic light is set to let vehicles pass an intersection periodically in certain way. With the sprawl of modern city, its traffic system is getting so complex that conventional way canâ??t improve its performance any more. So, based on system control theory, this paper makes traffic light control system optimized in three organic steps: first, adopts circular coloring method to determine the optimal phase number; then assigns proper green light time to each phase by fuzzy control rule; finally, improves current scheme on a 3-layered feedforward neural network. Simulation result demonstrates the effectiveness of this method.
Être reçu en audience chez le roi
Authors: Camus Alice
Published: July 2013

L’audience royale s’intègre dans le rituel quotidien de la vie de cour au temps de Louis XIV. Selon que l’audience est destinée à un courtisan ou à un représentant politique étranger, son rôle et son organisation diffèrent. Les courtisans qui obtiennent audience grâce à la faveur royale dont ils jouissent ou grâce à l’entremise d’influents intermédiaires sont reçus le plus souvent après le lever du roi ou après son dîner, dans son cabinet. Ce sont des entretiens assez brefs et relativement informels. En revanche, les audiences accordées aux représentants politiques étrangers sont bien plus codifiées. Elles sont de trois sortes : publiques, particulières ou secrètes. L’audience publique prend tout son sens dans son cérémonial, minutieux et imposant. Celui-ci est pensé comme le révélateur du rang et de l’importance accordés au ministre étranger reçu à la cour. Ainsi, il est nuancé par de multiples variations selon l’État du représentant politique et selon son caractère. Quant aux audiences particulières et secrètes, elles sont utiles à la politique royale. Elles sont l’occasion pour les ambassadeurs ou les envoyés présents à la cour de négocier la politique de leur souverain directement avec le roi.
Utiliser la polysémie de la résilience pour comprendre les différentes approches du risque et leur possible articulation
Authors: Reghezza-Zitt Magali
Published: July 2013

La résilience est un terme à la mode, qui souffre cependant de sa polysémie. Cet article propose de montrer deux choses. D’une part, cette polysémie est autant le fait de la construction pluridisciplinaire du concept que de la coexistence de deux paradigmes distincts au sein des sciences qui traitent du risque, les cindyniques. Le même mot de résilience relève ainsi deux conceptions du risque différentes, qui si elles ne sont pas exclusives l’une de l’autre, ne sont pas réductibles l’une à l’autre. D’autre part, il est possible de repositionner les différentes acceptions de la résilience en fonction des deux paradigmes pour lever les contradictions. La résilience devient alors un outil réflexif pour penser les cindyniques dans leur diversité et leurs complémentarités.
From resilience to viability: a case study of indigenous communities of the North Rupununi, Guyana
Authors: Berardi Andrea , Tschirhart Céline , Mistry Jayalaxshmi , Bignante Elisa , Haynes Lakeram , Albert Grace , Benjamin Ryan , Xavier Rebecca , Jafferally Deirdre
Published: July 2013

Le terme “résilience” a conquis une place importante dans le discours scientifique, et même à présent dans le langage courant. Or son utilisation reste souvent floue, puisqu’il peut être compris différemment : s’agit-il de résister ? De s’adapter ? De se transformer ? Cet article suggère l’utilisation d’un concept, la System Viability, ou la Viabilité des Systèmes. Ce concept permet d’appréhender six propriétés qui maximisent les chances d'un système de persister dans le temps, qu'il s'agisse d’écosystèmes ou de communautés. Dans cet article, nous appliquons et évaluons ce cadre conceptuel grâce à des méthodes visuelles participatives au sein de trois communautés indigènes du North Rupununi, au Guyana. Cet article tente de montrer que ce cadre conceptuel permet d’évaluer les stratégies de survie des communautés de manière cohérente et théoriquement corroborée, ce qui pourrait susciter l’intérêt de décideurs nationaux et internationaux en matière de résilience et durabilité.
De la vulnérabilité à la résilience : mutation ou bouleversement ?
Authors: Barroca Bruno , DiNardo Maryline , Mboumoua Irène
Published: July 2013

La vulnérabilité et la résilience sont deux concepts qui ont émergé dans des domaines différents et sont utilisés actuellement pour analyser et caractériser les risques. La notion de vulnérabilité constituait le paradigme dominant dans la caractérisation du risque et l’analyse des cyndiniques. Depuis les années 2000, la résilience est mobilisée plus fréquemment en géographie et en urbanisme notamment car le concept de vulnérabilité montre ses limites dans la compréhension des risques. Pour exister, la notion de résilience a évolué. Elle s’impose aujourd’hui comme une notion majeure dans l’analyse des risques. L’objectif de cet article est de comprendre comment le glissement sémantique s’est opéré entre vulnérabilité et résilience. A partir de l’analyse de bases de données, nous montrons que l’usage du terme de résilience est limité jusqu’au milieu des années 2000 puis se développe rapidement. Ensuite, nous tentons de proposer des hypothèses qui pourraient expliquer l’apparition et le développement rapide de la résilience. Enfin, nous essayerons de montrer le risque d’instrumentalisation du concept de résilience par les acteurs de l’aménagement.
La résilience face à la normativité et la solidarité des territoires
Authors: Daluzeau Julie , Gralepois Mathilde , Oger Clément
Published: July 2013

Le maintien et le développement des pôles urbains en zone inondable questionnent l’efficacité des politiques de prévention des risques basées sur la maîtrise de l’urbanisation. L’article analyse la résilience urbaine des représentations gestionnaires du risque dans les Plans de Prévention des Risques (PPR) du Val de Tours – Val de Luynes. Le concept de résilience révèle néanmoins les obstacles à son intégration dans la réglementation des zones inondables. D’une part, l’unicité de la norme dans l’application des PPR évacue toute possibilité de prise en compte de la résilience. D’autre part, la capacité d’adaptation et d’auto-organisation des habitants est une condition nécessaire afin d’assurer la pérennité d’une société face à une perturbation. Loin d’inciter à des pratiques de coopération et de solidarité, les changements de paradigme et d’échelle induits par la résilience se heurtent au manque de confiance entre les pouvoirs publics et la population.
Off the Paved Paths
Authors: Ryokai Kimiko , Agogino Alice
Published: July 2013

Mobile augmented reality (MAR) is an increasingly popular technology for enhancing how people interact with and learn about the environment and objects in the physical world. However, little is known about what aspects of a MAR interface can enhance student learning and engagement. Building on field observations and interviews with experts, and formative studies on how mobile learners navigate spaces using different interfaces, the authors have designed, built, and evaluated the GreenHat MAR application to help students learn about biodiversity and sustainability issues in their natural environment. The authors’ evaluation of the GreenHat MAR prototypes suggests that in comparison to a digital map on the same smartphone, MAR encouraged students to more carefully scrutinize physical field sites, and led them to make more personal discoveries to the subject matter being learned. They present the iterative design process, results from the authors’ studies, and discuss the implications for the design of mobile learning tools.
Modulation of Regulatory T Cell Function by Monocyte-Derived Dendritic Cells Matured through Electroporation with mRNA Encoding CD40 Ligand, Constitutively Active TLR4, and CD70
Authors: Pen Joeri J. , De Keersmaecker Brenda , Maenhout Sarah K. , Van Nuffel An M. T. , Heirman Carlo , Corthals Jurgen , Escors David , Bonehill Aude , Thielemans Kris , Breckpot Karine , Aerts Joeri L.
Published: July 2013

Regulatory T cells (Tregs) counteract anticancer immune responses through a number of mechanisms, limiting dendritic cell (DC)–based anticancer immunotherapy. In this study, we investigated the influence of various DC activation stimuli on the Treg functionality. We compared DCs activated by electroporation with mRNA encoding constitutively active TLR4 (caTLR4) and CD40 ligand (DiMix-DCs), or these factors together with mRNA encoding the costimulatory molecule CD70 (TriMix-DCs) with DCs maturated in the presence of a mixture of inflammatory cytokines (DCs maturated with a combination of the cytokines IL-1β, IL-6, TNF-α, and PGE2) for their ability to counteract Tregs on different levels. We first demonstrated that there was no difference in the extent of Treg induction starting from CD4+CD25− T cells under the influence of the different DC maturation stimuli. Second, we showed that both DiMix- and TriMix-DCs could partly alleviate Treg inhibition of CD8+ T cells. Third, we observed that CD8+ T cells that had been precultured with DiMix-DCs or TriMix-DCs were partially protected against subsequent Treg suppression. Finally, we showed that Tregs cocultured in the presence of TriMix-DCs, but not DiMix-DCs, partially lost their suppressive capacity. This was accompanied by a decrease in CD27 and CD25 expression on Tregs, as well as an increase in the expression of T-bet and secretion of IFN-γ, TNF-α, and IL-10, suggesting a shift of the Treg phenotype toward a Th1 phenotype. In conclusion, these data suggest that TriMix-DCs are not only able to suppress Treg functions, but moreover could be able to reprogram Tregs to Th1 cells under certain circumstances.
IL-17A Plays a Critical Role in the Pathogenesis of Liver Fibrosis through Hepatic Stellate Cell Activation
Authors: Tan Zhongming , Qian Xiaofeng , Jiang Runqiu , Liu Qianghui , Wang Youjing , Chen Chen , Wang Xuehao , Ryffel Bernhard , Sun Beicheng
Published: July 2013

Liver fibrosis is a severe, life-threatening clinical condition resulting from nonresolving hepatitis of different origins. IL-17A is critical in inflammation, but its relation to liver fibrosis remains elusive. We find increased IL-17A expression in fibrotic livers from HBV-infected patients undergoing partial hepatectomy because of cirrhosis-related early-stage hepatocellular carcinoma in comparison with control nonfibrotic livers from uninfected patients with hepatic hemangioma. In fibrotic livers, IL-17A immunoreactivity localizes to the inflammatory infiltrate. In experimental carbon tetrachloride–induced liver fibrosis of IL-17RA–deficient mice, we observe reduced neutrophil influx, proinflammatory cytokines, hepatocellular necrosis, inflammation, and fibrosis as compared with control C57BL/6 mice. IL-17A is produced by neutrophils and T lymphocytes expressing the Th17 lineage–specific transcription factor Retinoic acid receptor–related orphan receptor γt. Furthermore, hepatic stellate cells (HSCs) isolated from naive C57BL/6 mice respond to IL-17A with increased IL-6, α-smooth muscle actin, collagen, and TGF-β mRNA expression, suggesting an IL-17A–driven fibrotic process. Pharmacologic ERK1/2 or p38 inhibition significantly attenuated IL-17A–induced HSC activation and collagen expression. In conclusion, IL-17A+ Retinoic acid receptor–related orphan receptor γt+ neutrophils and T cells are recruited into the injured liver driving a chronic, fibrotic hepatitis. IL-17A–dependent HSC activation may be critical for liver fibrosis. Thus, blockade of IL-17A could potentially benefit patients with chronic hepatitis and liver fibrosis.
Functional Redundancy of MyD88-Dependent Signaling Pathways in a Murine Model of Histidyl-Transfer RNA Synthetase–Induced Myositis
Authors: Fernandez Irina , Harlow Lisa , Zang Yunjuan , Liu-Bryan Ru , Ridgway William M. , Clemens Paula R. , Ascherman Dana P.
Published: July 2013

We have previously shown that i.m. administration of bacterially expressed murine histidyl-tRNA synthetase (HRS) triggers florid muscle inflammation (relative to appropriate control proteins) in various congenic strains of mice. Because severe disease develops even in the absence of adaptive immune responses to HRS, we sought to identify innate immune signaling components contributing to our model of HRS-induced myositis. In vitro stimulation assays demonstrated HRS-mediated activation of HEK293 cells transfected with either TLR2 or TLR4, revealing an excitatory capacity exceeding that of other bacterially expressed fusion proteins. Corresponding to this apparent functional redundancy of TLR signaling pathways, HRS immunization of B6.TLR2−/− and B6.TLR4−/− single-knockout mice yielded significant lymphocytic infiltration of muscle tissue comparable to that produced in C57BL/6 wild-type mice. In contrast, concomitant elimination of TLR2 and TLR4 signaling in B6.TLR2−/−.TLR4−/− double-knockout mice markedly reduced the severity of HRS-induced muscle inflammation. Complementary subfragment analysis demonstrated that aa 60–90 of HRS were absolutely required for in vitro as well as in vivo signaling via these MyD88-dependent TLR pathways—effects mediated, in part, through preferential binding of exogenous ligands capable of activating specific TLRs. Collectively, these experiments indicate that multiple MyD88-dependent signaling cascades contribute to this model of HRS-induced myositis, underscoring the antigenic versatility of HRS and confirming the importance of innate immunity in this system.
TPL-2–ERK1/2 Signaling Promotes Host Resistance against Intracellular Bacterial Infection by Negative Regulation of Type I IFN Production
Authors: McNab Finlay W. , Ewbank John , Rajsbaum Ricardo , Stavropoulos Evangelos , Martirosyan Anna , Redford Paul S. , Wu Xuemei , Graham Christine M. , Saraiva Margarida , Tsichlis Philip , Chaussabel Damien , Ley Steven C. , O’Garra Anne
Published: July 2013

Tuberculosis, caused by Mycobacterium tuberculosis, remains a leading cause of mortality and morbidity worldwide, causing ∼1.4 million deaths per year. Key immune components for host protection during tuberculosis include the cytokines IL-12, IL-1, and TNF-α, as well as IFN-γ and CD4+ Th1 cells. However, immune factors determining whether individuals control infection or progress to active tuberculosis are incompletely understood. Excess amounts of type I IFN have been linked to exacerbated disease during tuberculosis in mouse models and to active disease in patients, suggesting tight regulation of this family of cytokines is critical to host resistance. In addition, the immunosuppressive cytokine IL-10 is known to inhibit the immune response to M. tuberculosis in murine models through the negative regulation of key proinflammatory cytokines and the subsequent Th1 response. We show in this study, using a combination of transcriptomic analysis, genetics, and pharmacological inhibitors, that the TPL-2–ERK1/2 signaling pathway is important in mediating host resistance to tuberculosis through negative regulation of type I IFN production. The TPL-2–ERK1/2 signaling pathway regulated production by macrophages of several cytokines important in the immune response to M. tuberculosis as well as regulating induction of a large number of additional genes, many in a type I IFN-dependent manner. In the absence of TPL-2 in vivo, excess type I IFN promoted IL-10 production and exacerbated disease. These findings describe an important regulatory mechanism for controlling tuberculosis and reveal mechanisms by which type I IFN may promote susceptibility to this important disease.
Irgm1 (LRG-47), a Regulator of Cell-Autonomous Immunity, Does Not Localize to Mycobacterial or Listerial Phagosomes in IFN-γ–Induced Mouse Cells
Authors: Springer Helen M. , Schramm Michael , Taylor Gregory A. , Howard Jonathan C.
Published: July 2013

The IFN-inducible protein Irgm1 (LRG-47) belongs to the family of immunity-related GTPases that function in cell-autonomous resistance against intracellular pathogens in mice. Irgm1 deficiency is associated with a severe immunodeficiency syndrome. The protein has been variously interpreted as a direct effector molecule on bacterial phagosomes or on other organelles or as an inducer of autophagy. In this study, we re-examined one of these claims, namely that Irgm1 targets mycobacterial and listerial phagosomes. We found no colocalization of endogenous Irgm1, using two immunofluorescent staining techniques, either in fibroblasts or in macrophages. We demonstrated the predicted existence of two protein isoforms of Irgm1 derived from differential splicing and described immunological reagents for their detection. Both Irgm1 isoforms localize to the Golgi apparatus and weakly to mitochondria; however, only the long Irgm1 isoforms can be detected on endolysosomal membranes. Together with the previous observation that the general immunodeficiency phenotype of Irgm1−/− mice is reversed in Irgm1/Irgm3 double-deficient mice, our results argue against a direct effector function of Irgm1 at the bacterial phagosome. We discuss these findings in the context of evidence that Irgm1 functions as a negative regulator of other members of the immunity-related GTPase protein family.
Occupational therapy synergy between Comprehensive Community Based Rehabilitation Tanzania and Heifer International to reduce poverty
Authors: Hansen Anne Marie W. , Chaki Albert P. , Mlay Ruth
Published: July 2013

Background: This article describes a partnership between a community-based rehabilitation organisation and a non-governmental organisation (NGO) in Tanzania. The partnership focused on income-generating (IG) activities to tackle the problems of poverty faced by families with a child with a disability (CWD). Objectives: The aim of this case study was to describe the partnership between Comprehensive Community Based Rehabilitation Tanzania in Moshi (CCBRT-Moshi), a non-governmental organisation, and families to create an income-generating business, namely raising goats.Method: This was a team approach between CCBRT-Moshi and Heifer International, an organisation that focuses on IG activities to create a synergy or partnership between community-based rehabilitation and IG activities.Results: This partnership between occupational therapy rehabilitation services at CCBRT-Moshi and the NGO resulted in strengthening the effectiveness of occupational therapy services and leaving a more lasting impact on the people they served within the community by helping to reduce poverty in addition to providing rehabilitation and prevention interventions.Conclusion: This collaboration was successful as it provided a means for families to generate income from raising goats. Although the results have not been empirically verified, observational and anecdotal evidence suggests that families with CWDs have better quality of life and ultimately improved health through this synergistic partnership.
Symmetric Genuine Spherical Whittaker
Functions on
Authors: Szpruch Dani
Published: July 2013

Let F be a p-adic field of odd residual characteristic. Let and be the metaplectic double covers of the general symplectic group and the symplectic group attached to the 2n dimensional symplectic space over F, respectively. Let σ be a genuine, possibly reducible, unramified principal series representation of . In these notes we give an explicit formula for a spanning set for the space of Spherical Whittaker functions attached to σ. For odd n, and generically for even n, this spanning set is a basis. The significant property of this set is that each of its elements is unchanged under the action of the Weyl group of . If n is odd, then each element in the set has an equivariant property that generalizes a uniqueness result proved by Gelbart, Howe, and Piatetski-Shapiro.Using this symmetric set, we construct a family of reducible genuine unramified principal series representations that have more then one generic constituent. This family contains all the reducible genuine unramified principal series representations induced from a unitary data and exists only for n even.
Projected effects of declining aerosols in RCP4.5: unmasking global warming?
Authors: Rotstayn L. D. , Collier M. A. , Chrastansky A. , Jeffrey S. J. , Luo J.-J.
Published: July 2013

Abstract. All the Representative Concentration Pathways (RCPs) include declining aerosol emissions during the 21st century, but the effects of these declines on climate projections have had little attention. Here we assess the global and hemispheric-scale effects of declining anthropogenic aerosols in RCP4.5 in CSIRO-Mk3.6, a model from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Results from this model are then compared with those from other CMIP5 models. We calculate the aerosol effective radiative forcing (ERF, including indirect effects) in CSIRO-Mk3.6 relative to 1850, using a series of atmospheric simulations with prescribed sea-surface temperatures. Global-mean aerosol ERF at the top of the atmosphere is most negative in 2005 (−1.47 W m−2). Between 2005 and 2100 it increases by 1.46 W m−2, i.e., it approximately returns to 1850 levels. Although increasing greenhouse gases (GHGs) and declining aerosols both exert a positive ERF at the top of the atmosphere during the 21st century, they have opposing effects on radiative heating of the atmosphere: increasing GHGs warm the atmosphere, whereas declining aerosols cool the atmosphere due to reduced absorption of shortwave radiation by black carbon. We then compare two projections for 2006–2100, using the coupled atmosphere-ocean version of the model. One (RCP45) follows the usual RCP4.5; the other (RCP45A2005) has identical forcing, except that emissions of anthropogenic aerosols and precursors are fixed at 2005 levels. The global-mean surface warming in RCP45 is 2.3 °C per 95 yr, of which almost half (1.1 °C) is caused by declining aerosols. The warming due to declining aerosols is almost twice as strong in the Northern Hemisphere as in the Southern Hemisphere, whereas that due to increasing GHGs is similar in the two hemispheres. For precipitation changes, the effects of declining aerosols are larger than those of increasing GHGs due to decreasing atmospheric absorption by black carbon: 63% of the projected global-mean precipitation increase of 0.16 mm per day is caused by declining aerosols. In the Northern Hemisphere, precipitation increases by 0.29 mm per day, of which 72% is caused by declining aerosols. Using data from 13 CMIP5 models, we find that projected global-mean surface warming in RCP4.5 is systematically larger in models that have more negative aerosol ERF in the present climate (r = −0.54, p = 0.03). A similar correlation is found for global-mean precipitation changes (r = −0.56, p = 0.02). These results suggest that aerosol forcing substantially modulates projected climate response in RCP4.5. In some respects, the effects of declining aerosols are quite distinct from those of increasing GHGs. Systematic efforts are needed to better quantify the role of declining aerosols in climate projections.
Characterization of disdrometer uncertainties and impacts on estimates of snowfall rate and radar reflectivity
Authors: Wood N. B. , L'Ecuyer T. S. , Bliven F. L. , Stephens G. L.
Published: July 2013

Abstract. Estimates of snow microphysical properties obtained by analyzing collections of individual particles are often limited to short time scales and coarse time resolution. Retrievals using disdrometer observations coincident with bulk measurements such as radar reflectivity and snowfall amounts may overcome these limitations; however, retrieval techniques using such observations require uncertainty estimates not only for the bulk measurements themselves, but also for the simulated measurements modeled from the disdrometer observations. Disdrometer uncertainties arise due to sampling and analytic errors and to the discrete, potentially truncated form of the reported size distributions. Imaging disdrometers such as the Snowflake Video Imager and 2-D Video Disdrometer provide remarkably detailed representations of snow particles, but view limited projections of their three-dimensional shapes. Particle sizes determined by such instruments underestimate the true dimensions of the particles in a way that depends, in the mean, on particle shape, also contributing to uncertainties. An uncertainty model that accounts for these uncertainties is developed and used to establish their contributions to simulated radar reflectivity and snowfall rate. Viewing geometry effects are characterized by a parameter, φ, that relates disdrometer-observed particle size to the true maximum dimension of the particle. Values and uncertainties for φ are estimated using idealized ellipsoidal snow particles. The model is applied to observations from seven snow events from the Canadian CloudSat CALIPSO Validation Project (C3VP), a mid-latitude cold season cloud and precipitation field experiment. Typical total uncertainties are 4 dBZ for reflectivity and 40–60% for snowfall rate, are highly correlated, and are substantial compared to expected observational uncertainties. The dominant sources of errors are viewing geometry effects and the discrete, truncated form of the size distributions. While modeled Ze-S relationships are strongly affected by assumptions about snow particle mass properties, such relationships are only modestly sensitive to φ owing to partially compensating effects on both the reflectivity and snowfall rate.
Increased soil temperature and atmospheric N deposition have no effect on the N status and growth of a mature balsam fir forest
Authors: D'Orangeville L. , Houle D. , Côté B. , Duchesne L. , Morin H.
Published: July 2013

Abstract. Nitrogen (N) is a major growth-limiting factor in boreal forest ecosystems. Increases of temperature and atmospheric N deposition are expected to affect forest growth directly and indirectly by increasing N availability due to higher rates of N mineralization. In order to understand the potential impacts of these changes, a mature balsam fir stand in Québec, Canada, was subjected during three consecutive growing seasons (2009–2011) to (i) experimentally increased soil temperature (4 °C) and earlier snowmelt (2–3 weeks) as well as (ii) increased inorganic N concentration in artificial precipitation (3 × current N concentrations using 15NH4-15NO3). Soil inorganic N was measured using buried ion-exchange membranes (PRS™ probes) and standard soil extractions. Dendrometers were used to monitor the variations in diameter growth and needles were analyzed annually for N to assess the nutritional response of trees. Results from the second (2010) and third (2011) year of treatment are reported. After three years of treatment, there was no significant increase in soil nitrate (NO3) or ammonium (NH4) availability either in the organic or in the mineral soil as measured with standard soil extractions. Similar results were obtained with ion-exchange membranes, except for NH4 in the forest floor, which increased by an average of 54% over the two years. No effect of treatments were observed on needle N or diameter growth, but an 8-day earlier peak in diameter growth was measured in heated plots in 2010. We attributed the limited effects of our treatments to the acute soil competition for available N at the site. As a result, the projected modifications of the forest N cycle and concomitant increased forest growth due to an earlier snowmelt, increased soil temperature and N deposition should be considered with caution in similar cold N-poor ecosystems.
Multi-decadal to-century NAO-like marine climate oscillations across the Denmark Strait (~66° N) over the last 2000 cal yr BP
Authors: Andrews J. T. , Jennings A. E.
Published: July 2013

Abstract. In the area of Denmark Strait (~66° N) the two modes of the North Atlantic Oscillation (NAO) are expressed in changes of the northward flux of Atlantic Water and the southward advection of Polar Water in the East Iceland Current. Proxies from marine cores along an environmental gradient from extensive to little or no drift ice, capture low frequency NAO-like variations over the last 2000 cal yr BP. Key proxies are the weight% of calcite, a measure of surface water stratification and nutrient supply, the weight% of quartz, a measure of drift ice transport, and grain-size. Records from Nansen and Kangerlussuaq fjords show variable ice-rafted debris (IRD) records but have distinct mineralogy associated with differences in the fjord catchment bedrock. High-resolution detrended records from Kangerlussuaq Trough show abrupt, significant multi-decadal changes (72 and 56 yr for calcite, and 94 and 65 yr for quartz), and parallel the 2000 yr Arctic summer temperature reconstructions. The calcite minimum occurred ca. 1550 AD whereas the quartz maxima occurred 200 yr earlier. Changes in calcite wt% from N and SW Iceland show similar abrupt changes to those in Kangerlussuaq Trough with an abrupt calcite peak ~1320 AD. Quartz values increased at two N Iceland sites in the last 500 yr whereas values declined in the East Greenland site.
Persistent millennial-scale link between Greenland climate and northern Pacific Oxygen Minimum Zone under interglacial conditions
Authors: Cartapanis O. , Tachikawa K. , Romero O. E. , Bard E.
Published: July 2013

Abstract. The intensity and/or extent of the northeastern Pacific Oxygen Minimum Zone (OMZ) varied in-phase with the Northern Hemisphere high latitude climate on millennial timescales during the last glacial period, indicating the presence of atmospheric and oceanic connections under glacial conditions. While millennial variability was observed for both the Greenland ice core and the northern Atlantic during the last interglacial period, the relationship with the northeastern Pacific OMZ has not yet been observed under warm interglacial conditions. Here we present a~new geochemical dataset, spanning the past 120 kyr, for major components (terrigenous fraction, marine organic matter, biogenic opal, and carbonates) by X-ray fluorescence scanning alongside with biological productivity and redox sensitive trace element content (Mo, Ni, Cd) of sediment core MD02-2508 at 23° N, retrieved from the northern limit of the modern OMZ. We evidenced high biological productivity from opal based on Si/Ti, and from Cd/Al, and Ni/Al ratios during last interglacial period. Highly resolved opal reconstruction presents millennial variability corresponding to all the Dansgaard–Oeschger interstadial events over the last interglacial, while the Mo/Al ratio indicates reduced oxygenation during these intervals. Extremely high opal content during warm interstadials suggests high diatom productivity. Despite the different climatic and oceanic background between glacial and interglacial periods, rapid variability in the northeastern Pacific OMZ seems to be tightly related to Northern Hemisphere high latitude climate mainly via atmospheric processes.
Potential surface temperature and shallow groundwater temperature response to climate change: an example from a small forested catchment in east-central New Brunswick (Canada)
Authors: Kurylyk B. L. , Bourque C. P.-A. , MacQuarrie K. T. B.
Published: July 2013

Abstract. Global climate models project significant changes to air temperature and precipitation regimes in many regions of the Northern Hemisphere. These meteorological changes will have associated impacts to surface and shallow subsurface thermal regimes, which are of interest to practitioners and researchers in many disciplines of the natural sciences. For example, groundwater temperature is critical for providing and sustaining suitable thermal habitat for cold-water salmonids. To investigate the surface and subsurface thermal effects of atmospheric climate change, seven downscaled climate scenarios (2046–2065) for a small forested catchment in New Brunswick, Canada were employed to drive the surface energy and moisture flux model, ForHyM2. Results from these seven simulations indicate that climate change-induced increases in air temperature and changes in snow cover could increase summer surface temperatures (range −0.30 to +3.49 °C, mean +1.49 °C), but decrease winter surface temperatures (range −1.12 to +0.08 °C, mean −0.53 °C) compared to the reference period simulation. Thus, changes to the timing and duration of snow cover will likely decouple changes in mean annual air temperature (mean +2.11 °C) and mean annual ground surface temperature (mean +1.06 °C). Projected surface temperature data were then used to drive an empirical surface to groundwater temperature transfer function developed from measured surface and groundwater temperature. Results from the empirical transfer function suggest that changes in groundwater temperature will exhibit seasonality at shallow depths (1.5 m), but be seasonally constant and approximately equivalent to the change in the mean annual surface temperature at deeper depths (8.75 m). The simulated increases in future groundwater temperature suggest that the thermal sensitivity of baseflow-dominated streams to decadal climate change may be greater than previous studies have indicated.
Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France
Authors: Barbu A. L. , Calvet J.-C. , Mahfouf J.-F. , Lafont S.
Published: July 2013

Abstract. The land monitoring service of the European Copernicus programme has developed a set of satellite-based biogeophysical products, including surface soil moisture (SSM) and leaf area index (LAI). This study investigates the impact of joint assimilation of remotely sensed SSM derived from ASCAT backscatter data and the GEOV1 satellite-based LAI into the ISBA-A-gs land surface model within the SURFEX modelling platform of Meteo-France. The ASCAT data were bias corrected with respect to the model climatology by using a seasonal-based CDF (Cumulative Distribution Function) matching technique. A multivariate multi-scale land data assimilation system (LDAS) based on the Extended Kalman Filter (EKF) is used for monitoring the soil moisture, terrestrial vegetation, surface carbon and energy fluxes across the France domain at a spatial resolution of 8 km. Each model grid box is divided in a number of land covers, each having its own set of prognostic variables. The filter algorithm is designed to provide a distinct analysis for each land cover while using one observation per grid box. The updated values are aggregated by computing a weighted average. In this study, it is demonstrated that the assimilation scheme works effectively within the ISBA-A-gs model over a four-year period (2008–2011). The EKF is able to extract useful information from the data signal at the grid scale and to distribute the root-zone soil moisture and LAI increments among the mosaic structure of the model. The impact of the assimilation on the vegetation phenology and on the water and carbon fluxes varies from one season to another. The spring drought of 2011 is an interesting case study showing the potential of the assimilation to improve drought monitoring. A comparison between simulated and in situ soil moisture gathered at the twelve SMOSMANIA stations shows improved anomaly correlations for eight stations.
Rogue waves in a wave tank: experiments and modeling
Authors: Lechuga A.
Published: July 2013

Abstract. In past decades theoretical studies have been carried out with the double aim of improving the knowledge of rogue wave main characteristics and of attempting to predict its sudden appearance. As an effort on this topic we tried the generation of rogue waves in a water wave tank using a symmetric spectrum (Akhmediev et al., 2011a) as input on the wave maker. To go on further the next step has been to apply a theoretical model to the envelope of these waves. After some considerations the best model has been an analogue of the Ginzburg–Landau equation.
Intermittency and multifractional Brownian character of geomagnetic time series
Authors: Consolini G. , De Marco R. , De Michelis P.
Published: July 2013

Abstract. The Earth's magnetosphere exhibits a complex behavior in response to the solar wind conditions. This behavior, which is described in terms of mutifractional Brownian motions, could be the consequence of the occurrence of dynamical phase transitions. On the other hand, it has been shown that the dynamics of the geomagnetic signals is also characterized by intermittency at the smallest temporal scales. Here, we focus on the existence of a possible relationship in the geomagnetic time series between the multifractional Brownian motion character and the occurrence of intermittency. In detail, we investigate the multifractional nature of two long time series of the horizontal intensity of the Earth's magnetic field as measured at L'Aquila Geomagnetic Observatory during two years (2001 and 2008), which correspond to different conditions of solar activity. We propose a possible double origin of the intermittent character of the small-scale magnetic field fluctuations, which is related to both the multifractional nature of the geomagnetic field and the intermittent character of the disturbance level. Our results suggest a more complex nature of the geomagnetic response to solar wind changes than previously thought.
A subglacial hydrological model dedicated to glacier sliding
Authors: de Fleurian B. , Gagliardini O. , Zwinger T. , Durand G. , Le Meur E. , Mair D. , Råback P.
Published: July 2013

Abstract. The flow of glaciers and ice-streams is strongly influenced by the presence of water at the interface between ice and bedrock. In this paper, a hydrological model evaluating the subglacial water pressure is developed with the final aim of estimating the sliding velocities of glaciers. The global model fully couples the subglacial hydrology and the ice dynamics through a water-dependent friction law. The hydrological part of the model follows a double continuum approach which relies on the use of porous layers to compute water heads in inefficient and efficient drainage systems. This method has the advantage of a relatively low computational cost that would allow its application to large ice bodies such as Greenland or Antarctica ice-streams. The hydrological model has been implemented in the finite element code Elmer/Ice, which simultaneously computes the ice flow. Herein, we present an application to the Haut Glacier d'Arolla for which we have a large number of observations, making it well suited to the purpose of validating both the hydrology and ice flow model components. The selection of hydrological, under-determined parameters from a wide range of values is guided by comparison of the model results with available glacier observations. Once this selection has been performed, the coupling between subglacial hydrology and ice dynamics is undertaken throughout a melt season. Results indicate that this new modelling approach for subglacial hydrology is able to reproduce the broad temporal and spatial patterns of the observed subglacial hydrological system. Furthermore, the coupling with the ice dynamics shows good agreement with the observed spring speed-up.