bluuebunny/crossref_metadata_2025 huggingface dataset:
Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990–2013
Authors: Andersson Camilla , Alpfjord Heléne , Robertson Lennart , Karlsson Per Erik , Engardt Magnuz
Published: June 2017

Abstract. We have constructed two data sets of hourly resolution reanalyzed near-surface ozone (O3) concentrations for the period 1990–2013 for Sweden. Long-term simulations from a chemistry-transport model (CTM) covering Europe were combined with hourly ozone concentration observations at Swedish and Norwegian background measurement sites using data assimilation. The reanalysis data sets show improved performance than the original CTM when compared to independent observations. In one of the reanalyzes we included all available hourly near-surface O3 observations, whilst in the other we carefully selected time-consistent observations in order to avoid introducing artificial trends. Based on the second reanalysis we investigated statistical aspects of the near-surface O3 concentration, focusing on the linear trend over the 24 year period. We show that high near-surface O3 concentrations are decreasing and low O3 concentrations are increasing, which is mirrored by observed improvement of many health and vegetation indices (apart from those with a low threshold). Using the chemistry-transport model we also conducted sensitivity simulations to quantify the causes of the observed change, focusing on three processes: change in hemispheric background, meteorology and anthropogenic emissions (Swedish and other European). The rising low concentrations of near-surface O3 in Sweden are caused by a combination of all three processes, whilst the decrease in the highest O3 concentrations is caused by O3 precursor emissions reductions. While studying the relative impact of anthropogenic emissions changes, we identified systematic differences in the modelled trend compared to observations that must be caused by incorrect trends in the utilised emissions inventory or by too high sensitivity of our model to emissions changes.
Hygroscopicity of organic surrogate compounds from biomass burning and their effect on the efflorescence of ammonium sulfate in mixed aerosol particles
Authors: Lei Ting , Zuend Andreas , Cheng Yafang , Su Hang , Wang Weigang , Ge Maofa
Published: June 2017

Abstract. Hygroscopic growth factors of organic surrogate compounds representing biomass burning and mixed organic-inorganic aerosol particles exhibit variability during dehydration experiments depending on their chemical composition, which we observed using a hygroscopicity tandem differential mobility analyzer (HTDMA). We observed that levoglucosan and humic acid aerosol particles release water slightly in the range of 90–5 % relative humidity (RH). 4-Hydroxybenzoic acid aerosol particles, however, remain in the solid state without diameter growth and even slightly shrinking at higher RH compared to the dry size. The measurements were accompanied by RH-dependent thermodynamic equilibrium calculations using the AIOMFAC and the E-AIM models, the ZSR relation, and a fitted hygroscopicity expression. We observed several effects of organic components on the hygroscopicity behavior of mixtures containing ammonium sulfate (AS) in relation to the different mass fractions of organic compounds: (1) a shift of efflorescence relative humidity (ERH) of ammonium sulfate to higher RH due to the presence of 25 wt % levoglucosan in the mixture. (2) There is a distinct efflorescence transition at 25 % RH for mixtures consisting of 25 wt % of 4-hydroxybenzoic acid compared to the ERH at 35 % for organic-free AS particles. (3) There is indication for a liquid-to-solid phase transition of 4-hydroxybenzoic acid in the mixed particles during dehydration. (4) A humic acid component shows no significant effect on the efflorescence of AS in mixed aerosol particles. In addition, relatively good measurement-model agreement in the case of the AIOMFAC and E-AIM models is mainly due to composition-dependent consideration of crystallization of AS in the model prediction. The use of the ZSR relation leads to good agreement with measured diameter growth factors of aerosol particles containing humic acid and ammonium sulfate. A similarity of the hygroscopicity parameter ĸ for organic surrogate compounds mixed with ammonium sulfate for different mass fractions during the different seasonal periods in the Amazon is observed. The RH-dependent hygroscopicity parameter ĸ measured at sub-saturated is consistent with kappa values for observations in the central Amazon Basin at the same environment, which suggests the similar O : C ratios and ammonium sulfate mass fraction in the laboratory and field observation conditions.
The effect of light on N2 fixation and net nitrogen release of field
Trichodesmium
Authors: Lu Yangyang , Wen Zuozhu , Shi Dalin , Chen Mingming , Zhang Yao , Bonnet Sophie , Li Yuhang , Tian Jiwei , Kao Shuh-Ji
Published: June 2017

Abstract. Dinitrogen fixation (NF) by marine cyanobacteria is a crucial pathway to replenish the oceanic bioavailable nitrogen inventory. Light is the key to modulate NF, however, field studies regarding light response curve (NF-I curve) of NF rate and the effect of light on diazotroph derived nitrogen (DDN) net release are missing that may hamper an accurate nitrogen model prediction. Uncontaminated 15N2 gas dissolution method was applied to examine how the light change may influence the NF intensity and DDN net release in the oligotrophic ocean. Experiments were conducted at stations with diazotrophs dominated by filamentous cyanobacterium Trichodesmium spp. in the Western Pacific and the South China Sea. The light effect on carbon fixation (CF) was measured in parallel using the 13C labelling method specifically for a station characterized by Trichodesmium bloom. Both NF-I and CF-I curves showed Ik (light saturation coefficient) range of 328 to 509 μE m−2 s−1 with saturation light at around 600 μE m−2 s−1. The proportion of DDN net release ranged from ~6% to ~50% revealing an increasing trend as the light intensity decreased. At the Trichodesmium bloom station, we found CF/NF ratio was light-dependent and the ratio started to increase as light was lower than the carbon compensation point of 300 μE m−2 s−1. NF pathway was likely preferentially blocked under low light to conserve energy for photosynthesis, thus, there is a metabolism tradeoff between carbon and nitrogen fixation pathways under light stress. Results showed that short-term light change modulates the physiological state, which subsequently determined the C/N metabolism and DDN net release of field Trichodesmium. Energy reallocation associated with the variations of field light intensity would be helpful for model prediction of global biogeochemical cycle involved with Trichodesmium.
Regional scaling of annual mean precipitation and water availability
with global temperature change
Authors: Greve Peter , Gudmundsson Lukas , Seneviratne Sonia I.
Published: June 2017

Abstract. Changes in regional water availability belong to the most crucial potential impacts of anthropogenic climate change, but are highly uncertain. It is thus of key importance for stakeholders to assess the possible implications of different global temperature thresholds on these quantities. Using a large subset of climate model simulations from the 5th phase of the Coupled Modeling Intercomparison Project (CMIP5), we derive here the sensitivity of regional changes in precipitation and precipitation minus evapotranspiration to global temperature changes. The simulations span the full range of available emissions scenarios and the sensitivities are derived using a modified pattern scaling approach. The applied approach assumes linear dependencies on global temperature changes while thoroughly addressing associated uncertainties via resampling methods. This allows us to assess the full distribution of the simulations in a probabilistic sense. Northern high latitude regions display robust responses towards a wetting, while subtropical regions display a tendency towards drying but with a large range of responses. Even though both internal variability and the scenario choice play an important role in the overall spread of the simulations, the uncertainty stemming from the climate model choice usually accounts for about half of the total uncertainty in most regions. We additionally assess the implications of limiting global mean temperature warming to values below (i) 2K or (ii) 1.5K (as stated within the 2015 Paris Agreement). We show that opting for the 1.5K-target might just slightly influence the mean response, but could substantially reduce the risk of experiencing extreme changes in regional water availability.
A probabilistic framework for the cover effect in bedrock erosion
Authors: Turowski Jens M. , Hodge Rebecca
Published: June 2017

Abstract. The cover effect in fluvial bedrock erosion is a major control on bedrock channel morphology and long-term channel dynamics. Here, we suggest a probabilistic framework for the description of the cover effect that can be applied to field, laboratory, and modelling data and thus allows the comparison of results from different sources. The framework describes the formation of sediment cover as a function of the probability of sediment being deposited on already alluviated areas of the bed. We define benchmark cases and suggest physical interpretations of deviations from these benchmarks. Furthermore, we develop a reach-scale model for sediment transfer in a bedrock channel and use it to clarify the relations between the sediment mass residing on the bed, the exposed bedrock fraction, and the transport stage. We derive system timescales and investigate cover response to cyclic perturbations. The model predicts that bedrock channels can achieve grade in steady state by adjusting bed cover. Thus, bedrock channels have at least two characteristic timescales of response. Over short timescales, the degree of bed cover is adjusted such that the supplied sediment load can just be transported, while over long timescales, channel morphology evolves such that the bedrock incision rate matches the tectonic uplift or base-level lowering rate.
Assessing floods and droughts in the Mékrou River Basin (West
Africa): A combined household survey and climatic trends analysis approach
Authors: Markantonis Vasileios , Farinosi Fabio , Dondeynaz Celine , Ameztoy Iban , Pastori Marco , Marletta Luca , Ali Abdou , Carmona Moreno Cesar
Published: June 2017

Abstract. The assessment of natural hazards such as floods and droughts is a complex issue demanding integrated approaches and high quality data. Especially in African developing countries, where information is limited, the assessment of floods and droughts, though an overarching issue influencing economic and social development, is even more challenging. This paper presents an integrated approach to assess crucial aspects of floods and droughts in the transboundary Mekrou River basin (a portion of the Niger basin in West Africa) combining climatic trends analysis and the findings of a household survey. The multi-variables trend analysis estimates at the biophysical level the climate variability and the occurrence of floods and droughts. These results are coupled with the analysis of household survey data that reveal behaviors and opinions of the local residents regarding the observed climate variability and occurrence of flood and drought events, household mitigation measures and impacts of floods and droughts. Furthermore, two econometric models are set up to estimate the costs of floods and droughts of impacted households during a two years period (2014–2015) resulting into an average cost of approximately 495 euro per household for floods and 391 euro per household for droughts.
Assessing and analysing the impact of land take pressures on arable land
Authors: Aksoy Ece , Gregor Mirko , Schröder Christoph , Löhnertz Manuel , Louwagie Geertrui
Published: June 2017

Abstract. Land, and in particular soil, is a finite and essentially non-renewable resource. Across the European Union, land take, i.e. the increase of settlement area over time, annually consumes more than 1000 km2 of which half is actually sealed and hence lost under impermeable surfaces. Land take, and in particular soil sealing, has already been identified as one of the major soil threats in the 2006 European Commission Communication Towards a Thematic Strategy on Soil Protection and the Soil Thematic Strategy and has been confirmed as such in the report on the implementation of this strategy. The aim of this study is to relate the potential of land for a particular use in a given region with the actual land use. This allows evaluating whether land (especially the soil dimension) is used according to its (theoretical) potential. To this aim, the impact of several land cover flows related to urban development on soils with good, average, and poor production potentials were assessed and mapped. Thus, the amount and quality (potential for agricultural production) of arable land lost between the years 2000 and 2006 was identified. In addition, areas with high productivity potential around urban areas, indicating areas of potential future land use conflicts for Europe, were identified.
Wind inflow observation from load harmonics
Authors: Bertelè Marta , Bottasso Carlo L. , Cacciola Stefano , Daher Adegas Fabiano , Delport Sara
Published: June 2017

Abstract. The wind field leaves its fingerprint on the rotor response. This fact can be exploited to use the rotor as a sensor: by looking at the rotor response, in the present case in terms of blade loads, one may infer the wind characteristics. This paper describes a wind state observer that estimates four wind parameters, namely the vertical and horizontal shears and the yaw and upflow misalignment angles, from out-of-plane and in-plane blade bending moments. The resulting observer provides on-rotor wind inflow characteristics that can be exploited for wind turbine and wind farm control. The proposed formulation is evaluated by extensive numerical simulations in turbulent and non-turbulent wind conditions using a high-fidelity aeroservoelastic model of a multi-MW wind turbine.
Habitar as fronteiras
Authors: De Oliveira Vera Lúcia
Published: June 2017

Este artigo apresenta uma reflexão sobre a escrita poética em duas línguas, no caso, o português e o italiano, e sobre dinâmicas e questões ligadas à posição da autora, que optou por habitar espaços de fronteiras linguísticas, geográficas e existenciais.
Marco contextual demografico la educación superior en la red educativa UNAH de la región occidental, CUROC
Authors: Castillo Bertrán Norma Adriana
Published: June 2017

El presente artículo está enmarcado en el proyecto de “Oferta y Demanda de la Educación Superior de Honduras” realizado por la Universidad Nacional Autónoma de Honduras (UNAH), a través del Instituto de Investigaciones Económicas y Sociales (IIES). Con este proyecto se pretende estudiar la educación superior en Honduras donde se propone crear un modelo sistémico que integra una cadena de valor y de suministro de educación superior que incluye las entradas y salidas de educación superior.La Red Educativa UNAH de la Región Occidente que aglutina los departamentos de Copán, Ocotepeque y Lempira, la cual esta constituida por el Centro Universitario Regional de Occidente (CUROC) con sede en Santa Rosa de Copán y el CASUED de La Entrada. Este estudio comprende el tamaño y ritmo de crecimiento de la población, la estructura por edad y sexo, el comportamiento de las principales variables demográficas como son la fecundidad, mortalidad y la migración (interna e internacional), la distribución espacial y varios aspectos de la población en edad de estudiar la educación terciaria y el mercado laboral de la región.La población total de la región en 2011 (según datos proyectados del censo 2001) es 3.5 veces más que la de 1950 y 1.3 veces que la existente en el 2001. La estructura de la población de esta zona es joven; actualmente, los menores de 15 años están representados por el 43.1%, los de 15-64 años están constituidos por el 53.1% y los mayores de 65 por el 3.8% el cambio suscitado en la estructura por edad ha sido producto del inicio en la reducción de la fecundidad; pero que aun sigue siendo alta.La población en edad terciaria de la región esta creciendo aceleradamente y seguirá creciendo en las próximas décadas por lo cual demandará mayores servicios de educación. En la población de 18-24 años la proporción de hombres es mayor que las mujeres, en vista que esta zona es eminentemente rural y las mujeres jóvenes prefieren migrar a las ciudades cercanas en busca de empleo.Los principales indicadores demográficos de la dinámica demográfica (fecundidad, mortalidad) presentan niveles altos comparados con los niveles nacionales para ambos periodos Con respecto a la migración la región no solo es expulsora a nivel interno sino que también al exterior. A nivel internacional, los inmigrantes que recibe esta zona provienen de los países centroamericanos, donde el 85.7% lo aportan los países vecinos de Guatemala y El Salvador; debido a su cercanía y a su fácil movilidad a dichos países.
Tecnología de procesos: Alcances y limitaciones
Authors: Flores Silva Jorge
Published: June 2017

La tecnología de procesos y su implementación es básica en los distintos sectores de la economía.- Su optimización para alcanzar las metas u objetivos de la empresa requiere que la tecnología no sólo sea la más novedosa, sino también que sea capaz de garantizar la sostenibilidad de la naturaleza en función de la vida. En la medida que las tecnologías se desechen rápidamente, sus sustituciones pueden volverse anti-ecológicas, sino existe un proceso de sostenibilidad que lo acompañe.Si el promedio de vida de la tecnología disminuye, también el promedio de vida del ser humano puede tender a disminuir debido a una posible disminución del promedio de vida de la naturaleza.-Si la tecnología de procesos solo toman en cuenta la máxima eficiencia para incrementar el rendimiento económico sin considerar los costos sociales y ambientales, sería una práctica irracional del uso de los recursos que desemboca en la autodestrucción.La tecnología de procesos para evitar al máximo los males que acarrea la racionalidad formal que termina en irracionalidad debe estar fundada en la investigación. Investigar para desarrollarse y no solo para crecer, desarrollo que debe estar fundado en la persona y en la naturaleza para la reproducción de la vida. En este caso, el conocimiento creado por la investigación no se agota, sino que queda acumulado y debe estimularse para la creación de ciencia y tecnología. Dicho conocimiento se va construyendo como parte de la práctica social.
¿Es la comunicación en la empresa una competencia que debe desarrollarse?
Authors: Argueta Moreno Jesus David , Martel Justa Rufina
Published: June 2017

La presente investigación de corte cualitativo, efectúa una reflexión sobre la relevancia del fortalecimiento de las competencias en el ámbito empresarial y de forma particular sobre las competencias comunicativas, al desarrollar un reconocimiento el sustento teórico que documenta y describe las bondades originadas por el acertado estímulo/apoyo de las Competencias en la Comunicación. Determinando así la trascendencia de este tipo de competencias, respecto a la adecuada gestión y coordinación de los esfuerzos colectivos e individuales.
El uso de las tecnologías de información como medio de alfabetización en las instituciones de educación de Honduras
Authors: Raudales García Nelson Roberto
Published: June 2017

La era de las Nuevas Tecnologías de la información y comunicación (NTIC´s) han influenciado de diversas formas en la vida de los seres humanos, hoy en día es inevitable su aplicación y uso de tales herramientas para el desarrollo de actividades médicas, científicas, investigación e innovación en las diversas áreas del saber. Por consiguiente el uso de tales herramientas en la transferencia de conocimientos no queda separado del desarrollo de actividades aplicables en las Instituciones de Educación Superior (IES) para lograr trascender en la vida económica de las personas y/o en la inclusión de medidas orientadas a mejorar las políticas públicas.Asimismo, a nivel operativo de IES se vuelve imperante el reto que involucre a su personal en desempeñar el proceso de transformación y actualización académico-curricular docente, para lograr aprovechar al máximo tales propósitos sin desestimar en la medida de lo posible el establecimiento y aplicación de medios/políticas educativas que permitan a las IES incursionar eficientemente en tales iniciativas.Además, el personal docente encargado de los procesos de enseñanza y/o transferencia de conocimientos debe disponer de las habilidades que les permitan trascender, o estar dispuestos a lograr la asimilación de tales herramientas para los fines requeridos  ello para adaptarse de manera progresiva y constante a los cambios que dicho fenómeno globalizante conlleva.
Analyzing Settlement Patterns of Bronze Age Sites at Bostan Abad, according Regional Archaeological Survey
Authors: Velayati Rahim , Khanali Hamid
Published: June 2017

Archaeological surveys always present deep information about history of any given geographical area to archaeologists. Archaeologists have surveyed many Iranian regional areas, however, Bostan Abad, Eastern Azerbaijan, is among regions rarely archaeologically investigated. Present paper involves in analyzing settlement patterns and typology of Bronze Age of Bostan Abad according archaeological surveys at 1391 and 1392. Accordingly, some 36 Bronze Age sites identified, with two sites of Early Bronze Age, while the other remains date to Middle and Late Bronze Ages. It should be noted that archaeological survey based on surficial collected data, which make distinguishing Middle and Late Bronze Age a hard task. Conclusions signify from two aspects: from one hand, one should point to a geographical key role in locating settlements, on the other hand, typology of Potteries indicate inter regional communications, and strategic location of Bostan Abad. This zone is one of the most important hallways between Central Plateau of Iran and Northwest of Iran; however, regional investigations and connective role of the region and expansion of various cultures could reveal significant implications.
STYLE RADZENIA SOBIE ZE STRESEM A STOSUNEK DO PRZYSZŁOŚCI
U RODZICÓW OSÓB Z NIEPEŁNOSPRAWNOŚCIĄ INTELEKTUALNĄ
Authors: Korpowicz Anna
Published: June 2017

Celem artykułu jest zwrócenie uwagi na zależności pomiędzy stylem radzenia sobie ze stresem a stosunkiem do przyszłości u rodziców wychowujących osoby z niepełnosprawnością intelektualną. Postawiono hipotezę, że rodzice stosujący zadaniowy styl radzenia sobie ze stresem najbardziej optymistycznie myślą o przyszłości swoich niepełnosprawnych dzieci. Hipoteza ta nie znalazła potwierdzenia w badaniach. Okazało się, że największym optymizmem cechują się osoby stosujące unikający styl radzenia sobie, co może mieć związek zarówno ze stosowaniem mechanizmów obronnych, takich jak zaprzeczanie, jak i z potencjalnie większą dostępną siecią wsparcia społecznego.
Quels déterminants de la prise de risque? Les réponses de l’économie expérimentale
Authors: Beaud Mickael , Willinger Marc
Published: June 2017

Nous passons en revue les méthodes d’élicitation des préférences pour le risque avec incitations réelles, afin de mettre en évidence les principaux déterminants de la prise de risque identifiés grâce à ces méthodes. Dans un premier temps nous présentons l’état des connaissances quant à ces déterminants (le genre, l’âge et la richesse), et dans un second temps, nous mettons en avant deux domaines qui affectent la prise de risque et pour lesquels l’état des connaissances reste insuffisant : la présence de risque inassurable et l’interaction entre les préférences temporelles et les préférences pour le risque.
La question du vote. Expérimentations en laboratoire et In Situ
Authors: Igersheim Herrade , Baujard Antoinette , Laslier Jean-François
Published: June 2017

Cet article est une revue de la littérature sur les expérimentations de vote qui étudient les comportements des votants et les propriétés des modes de scrutin. Tout d’abord, nous décrivons les expérimentations menées en laboratoire autour de trois aspects principaux : résultats agrégés selon le mode de scrutin, vote stratégique, paradoxe du vote. Nous abordons ensuite les expérimentations In Situ, typiques de l’étude expérimentale du vote, consistant à tester en marge d’élections officielles d’envergure des méthodes de vote alternatives. Nous étudions le protocole expérimental, deux enseignements généraux – l’accueil et les réactions des électeurs – ainsi que deux enseignements spécifiques – la comparaison des résultats agrégés et la description de l’offre politique telle que perçue par les électeurs.
Le jeu de l’ultimatum, une méta-analyse de 30 années de recherches expérimentales
Authors: Tisserand Jean-Christian
Published: June 2017

Le jeu de l’ultimatum recense sans nul doute l’une des plus larges littératures expérimentales de ces trois dernières décennies. Dans cet article, nous nous intéressons aux décisions des joueurs dans le jeu de l’ultimatum ainsi qu’aux variables explicatives susceptibles d’influencer la somme offerte. Nous réalisons une méta-analyse portant sur un total de 97 observations du jeu simple de l’ultimatum recueillies à travers 42 articles publiés entre 1983 et 2012. Alors que la prédiction théorique annonce que les offres du jeu de l’ultimatum devraient être nulles, nos résultats mettent en évidence que ce choix procure un gain espéré de 7,69 % de la somme en jeu pour le proposant. Alors que le gain espéré du proposant est à son maximum lorsque ce dernier offre 40 % de la somme à partager, la moyenne pondérée des offres formulées par les proposants de notre échantillon d’études s’établit à 41,04 %. Parmi les variables explicatives étudiées, seul le fait d’être un étudiant en économie présente un impact significatif sur les sommes offertes. Ce résultat va dans le sens de l’étude menée par Carter et Irons (1991).
Représentativité et hétérogénéité des préférences dans les expériences de laboratoire
Authors: Attallah May
Published: June 2017

Ces dernières années, il y a eu un développement considérable de l’économie expérimentale. Conformément à la critique de Henrichet al.(2010), la majorité des données et des recherches en sciences comportementales est basée sur des échantillons tirés de populations occidentales, formées, industrialisées, riches et démocratiques. Néanmoins, malgré le caractère restreint de leurs échantillons, les chercheurs tirent souvent des conclusions concernant les préférences humaines en général. Dans cet article, nous proposons une synthèse et un point de vue sur la représentativité des résultats issus des expériences de laboratoire et de terrain qui visent à expliquer les préférences sociales, les préférences concernant le risque et le temps. Nous montrons qu’il existe effectivement des différences incontestables entre les populations d’étudiants et d’autres populations plus générales. Cependant, nous montrons que ce résultat n’est pas une généralité et que l’hétérogénéité reste également présente au sein d’une même population.
QUELLE CONVERGENCE POUR LES PRIMES DE RISQUE SUR LES MARCHÉS BOURSIERS? UNE ANALYSE SUR DES DONNéES INTERNATIONALES DE 1984 À 2007
Authors: ABDESSELAM Rafik , LECARPENTIER-MOYAL Sylvie , RENOU-MAISSANT Patricia
Published: June 2017

L’objet de cet article est d’étudier empiriquement la convergence internationale des marchés des actions, à partir de l’analyse temporelle des primes de risqueex postet, d’identifier dans quelle mesure les composantes des primes permettent d’expliquer ce mouvement de convergence observé sur 11 marchés boursiers durant la période 1984-2007. Pour ce faire, a été développée une approche originale combinant une analyse de la convergence des primes par le biais d’un modèle à coefficients variables et une analyse multidimensionnelle sur données évolutives des composantes des primes de risque. La première méthode permet d’identifier un phénomène de convergence internationale des primes de risque des actions vers le marché américain. Cependant, le processus n’est pas achevé et semble même interrompu pour la plupart des pays européens depuis le milieu des années 1990. En outre, la convergence européenne des primes est clairement établie entre cinq pays européens (Allemagne, Belgique, France, Italie et Pays-Bas). La seconde méthode met en exergue de fortes similitudes entre les marchés des actions européen, canadien et américain, alors que les marchés allemand et suisse se rapprochent davantage du marché japonais.
L’histoire du concept d’équilibre en sciences économiques
Authors: DÜPPE Till
Published: June 2017

Le concept d’équilibre permet d’identifier le domaine de théorie économique dans la recherche actuelle en économie. Cette place prépondérante a plusieurs origines historiques. Avant même que la notion d’équilibre fasse son apparition, les arguments d’équilibre se retrouvaient dans les écrits du XVIIe siècle sur le commerce. C’est à la fin du XVIIIe siècle qu’il entre dans le vocabulaire des économistes politiques. C’était un concept analogique et surtout normatif se rapportant à l’ordre naturel de l’économie. À la fin du XIXe siècle, il s’enrichit d’une signification analytique, principalement grâce à la différenciation entre équilibre statique et dynamique. Entre les années 1940 et 1960, le concept évolue en notion métathéorique, devenant la pierre angulaire de l’analyse axiomatique de l’équilibre général; cette dernière deviendra le fondement de la modélisation mathématique actuelle. On retrouve également le concept dans la théorie des jeux, où il est le principal outil d’analyse sans être restreint à l’étude des marchés concurrentiels; il permet la formalisation d’environnements institutionnels et d’interactions stratégiques au niveau d’un individu ou d’un groupe. Dans presque tout modèle macroéconomique, la théorie de l’équilibre général reste le point de référence principal.
L’évolution des Accords de Bâle : d’une approche microprudentielle à un cadre macroprudentiel
Authors: HENNANI Rachida
Published: June 2017

La crise financière des subprimes a conduit les autorités prudentielles à repenser le cadre normatif des Accords de Bâle pour y inclure un volet macroprudentiel. Cette vision plus générale des risques doit permettre de pallier les insuffisances des Accords dits Bâle I et Bâle II, qui s’inscrivent exclusivement dans une vision microprudentielle des risques. Cet article analyse l’ajustement des Accords de Bâle pour faire face aux défis présentés par la crise de 2008. La récente évolution vers un cadre macroprudentiel est liée aux failles générées par la généralisation fallacieuse de l’évaluation individualisée des risques financiers. Le nouvel Accord (Bâle III) inclut une exigence en fonds propres pour des risques globaux. Néanmoins, les défis auxquels sont confrontées les autorités de régulation restent nombreux.
Reflections on the intercultural politics of food, diet, and nutrition research in Canadian Inuit communities
Authors: Fletcher Christopher
Published: June 2017

This essay explores the intercultural dynamics of food and health research in Inuit communities over time. Multiple sources of information are used to explore Inuit subjectivity in research through different ways of conceptualizing and acting on food-related practice and knowledge. How people experience being the subject of research, how that research mobilizes knowledge and resources, and how these in turn feed back into the larger social field is an important part of an intercultural dynamic in the Inuit Nunangat. Scientific interest in the Inuit diet is among the oldest of preoccupations in the health field, stretching back to the earliest encounters of Europeans with Inuit. Today, diet-related health issues are still a major area of scientific investigation and public health intervention. A deeper consideration of both Inuit and researcher cultures in food and diet-related health research will lead to more effective health promotion activities in Inuit communities.
Microbiota regulates visceral pain in the mouse
Authors: Luczynski Pauline , Tramullas Monica , Viola Maria , Shanahan Fergus , Clarke Gerard , O'Mahony Siobhain , Dinan Timothy G , Cryan John F
Published: June 2017

The perception of visceral pain is a complex process involving the spinal cord and higher order brain structures. Increasing evidence implicates the gut microbiota as a key regulator of brain and behavior, yet it remains to be determined if gut bacteria play a role in visceral sensitivity. We used germ-free mice (GF) to assess visceral sensitivity, spinal cord gene expression and pain-related brain structures. GF mice displayed visceral hypersensitivity accompanied by increases in Toll-like receptor and cytokine gene expression in the spinal cord, which were normalized by postnatal colonization with microbiota from conventionally colonized (CC). In GF mice, the volumes of the anterior cingulate cortex (ACC) and periaqueductal grey, areas involved in pain processing, were decreased and enlarged, respectively, and dendritic changes in the ACC were evident. These findings indicate that the gut microbiota is required for the normal visceral pain sensation.
A large gene family in fission yeast encodes spore killers that subvert Mendel’s law
Authors: Hu Wen , Jiang Zhao-Di , Suo Fang , Zheng Jin-Xin , He Wan-Zhong , Du Li-Lin
Published: June 2017

Spore killers in fungi are selfish genetic elements that distort Mendelian segregation in their favor. It remains unclear how many species harbor them and how diverse their mechanisms are. Here, we discover two spore killers from a natural isolate of the fission yeast Schizosaccharomyces pombe. Both killers belong to the previously uncharacterized wtf gene family with 25 members in the reference genome. These two killers act in strain-background-independent and genome-location-independent manners to perturb the maturation of spores not inheriting them. Spores carrying one killer are protected from its killing effect but not that of the other killer. The killing and protecting activities can be uncoupled by mutation. The numbers and sequences of wtf genes vary considerably between S. pombe isolates, indicating rapid divergence. We propose that wtf genes contribute to the extensive intraspecific reproductive isolation in S. pombe, and represent ideal models for understanding how segregation-distorting elements act and evolve.
The Venice specimen ofOuranosaurus nigeriensis(Dinosauria, Ornithopoda)
Authors: Bertozzo Filippo , Dalla Vecchia Fabio Marco , Fabbri Matteo
Published: June 2017

Ouranosaurus nigeriensisis an iconic African dinosaur taxon that has been described on the basis of two nearly complete skeletons from the Lower Cretaceous Gadoufaoua locality of the Ténéré desert in Niger. The entire holotype and a few bones attributed to the paratype formed the basis of the original description by Taquet (1976). A mounted skeleton that appears to correspond toO. nigeriensishas been on public display since 1975, exhibited at the Natural History Museum of Venice. It was never explicitly reported whether the Venice specimen represents a paratype and therefore, the second nearly complete skeleton reported in literature or a third unreported skeleton. The purpose of this paper is to disentangle the complex history of the various skeletal remains that have been attributed toOuranosaurus nigeriensis(aided by an unpublished field map of the paratype) and to describe in detail the osteology of the Venice skeleton. The latter includes the paratype material (found in 1970 and collected in 1972), with the exception of the left femur, the right coracoid and one manus ungual phalanx I, which were replaced with plaster copies, and (possibly) other manus phalanges. Some other elements (e.g., the first two chevrons, the right femur, the right tibia, two dorsal vertebrae and some pelvic bones) were likely added from other individual/s. The vertebral column of the paratype was articulated and provides a better reference for the vertebral count of this taxon than the holotype. Several anatomical differences are observed between the holotype and the Venice specimen. Most of them can be ascribed to intraspecific variability (individual or ontogenetic), but some are probably caused by mistakes in the preparation or assemblage of the skeletal elements in both specimens. The body length of the Venice skeleton is about 90% the linear size of the holotype. Osteohistological analysis (the first for this taxon) of some long bones, a rib and a dorsal neural spine reveals that the Venice specimen is a sub-adult; this conclusion is supported by somatic evidence of immaturity. The dorsal ‘sail’ formed by the elongated neural spines of the dorsal, sacral and proximal caudal vertebrae characterizes this taxon among ornithopods; a display role is considered to be the most probable function for this bizarre structure. Compared to the mid-1970s, new information from the Venice specimen and many iguanodontian taxa known today allowed for an improved diagnosis ofO. nigeriensis.
Focus expansion and stability of the spread parameter estimate of the power law model for dispersal gradients
Authors: Ojiambo Peter S. , Gent David H. , Mehra Lucky K. , Christie David , Magarey Roger
Published: June 2017

Empirical and mechanistic modeling indicate that pathogens transmitted via aerially dispersed inoculum follow a power law, resulting in dispersive epidemic waves. The spread parameter (b) of the power law model, which is an indicator of the distance of the epidemic wave front from an initial focus per unit time, has been found to be approximately 2 for several animal and plant diseases over a wide range of spatial scales under conditions favorable for disease spread. Although disease spread and epidemic expansion can be influenced by several factors, the stability of the parameter b over multiple epidemic years has not been determined. Additionally, the size of the initial epidemic area is expected to be strongly related to the final epidemic extent for epidemics, but the stability of this relationship is also not well established. Here, empirical data of cucurbit downy mildew epidemics collected from 2008 to 2014 were analyzed using a spatio-temporal model of disease spread that incorporates logistic growth in time with a power law function for dispersal. Final epidemic extent ranged from 4.16 ×108 km2 in 2012 to 6.44 ×108 km2 in 2009. Current epidemic extent became significantly associated (P < 0.0332; 0.56 < R2 < 0.99) with final epidemic area beginning near the end of April, with the association increasing monotonically to 1.0 by the end of the epidemic season in July. The position of the epidemic wave-front became exponentially more distant with time, and epidemic velocity increased linearly with distance. Slopes from the temporal and spatial regression models varied with about a 2.5-fold range across epidemic years. Estimates of b varied substantially ranging from 1.51 to 4.16 across epidemic years. We observed a significant b ×time (or distance) interaction (P < 0.05) for epidemic years where data were well described by the power law model. These results suggest that the spread parameter b may not be stable over multiple epidemic years. However, b ≈ 2 may be considered the lower limit of the distance traveled by epidemic wave-fronts for aerially transmitted pathogens that follow a power law dispersal function.
Non‐Equilibrium Assembly of Light‐Activated Colloidal Mixtures
Authors: Singh Dhruv P. , Choudhury Udit , Fischer Peer , Mark Andrew G.
Published: June 2017

The collective phenomena exhibited by artificial active matter systems present novel routes to fabricating out‐of‐equilibrium microscale assemblies. Here, the crystallization of passive silica colloids into well‐controlled 2D assemblies is shown, which is directed by a small number of self‐propelled active colloids. The active colloids are titania–silica Janus particles that are propelled when illuminated by UV light. The strength of the attractive interaction and thus the extent of the assembled clusters can be regulated by the light intensity. A remarkably small number of the active colloids is sufficient to induce the assembly of the dynamic crystals. The approach produces rationally designed colloidal clusters and crystals with controllable sizes, shapes, and symmetries. This multicomponent active matter system offers the possibility of obtaining structures and assemblies that cannot be found in equilibrium systems.
Quantum Mechanics/Molecular Mechanics Study on the Photoreactions of Dark‐ and Light‐Adapted States of a Blue‐Light YtvA LOV Photoreceptor
Authors: Chang Xue‐Ping , Gao Yuan‐Jun , Fang Wei‐Hai , Cui Ganglong , Thiel Walter
Published: June 2017

The dark‐ and light‐adapted states of YtvA LOV domains exhibit distinct excited‐state behavior. We have employed high‐level QM(MS‐CASPT2)/MM calculations to study the photochemical reactions of the dark‐ and light‐adapted states. The photoreaction from the dark‐adapted state starts with an S1→T1 intersystem crossing followed by a triplet‐state hydrogen transfer from the thiol to the flavin moiety that produces a diradical intermediate, and a subsequent internal conversion that triggers a barrierless C−S bond formation in the S0 state. The energy profiles for these transformations are different for the four conformers of the dark‐adapted state considered. The photochemistry of the light‐adapted state does not involve the triplet state: photoexcitation to the S1 state triggers C−S bond cleavage followed by recombination in the S0 state; both these processes are essentially barrierless and thus ultrafast. The present work offers new mechanistic insights into the photoresponse of flavin‐containing blue‐light photoreceptors.
An Intrinsically Stretchable and Compressible Supercapacitor Containing a Polyacrylamide Hydrogel Electrolyte
Authors: Huang Yan , Zhong Ming , Shi Fukuan , Liu Xiaoying , Tang Zijie , Wang Yukun , Huang Yang , Hou Haoqing , Xie Xuming , Zhi Chunyi
Published: June 2017

Stretchability and compressibility of supercapacitors is an essential element of modern electronics, such as flexible, wearable devices. Widely used polyvinyl alcohol‐based electrolytes are neither very stretchable nor compressible, which fundamentally limits the realization of supercapacitors with high stretchability and compressibility. A new electrolyte that is intrinsically super‐stretchable and compressible is presented. Vinyl hybrid silica nanoparticle cross‐linkers were introduced into polyacrylamide hydrogel backbones to promote dynamic cross‐linking of the polymer networks. These cross‐linkers serve as stress buffers to dissipate energy when strain is applied, providing a solution to the intrinsically low stretchability and compressibility shortcomings of conventional supercapacitors. The newly developed supercapacitor and electrolyte can be stretched up to an unprecedented 1000 % strain with enhanced performance, and compressed to 50 % strain with good retention of the initial performance.
The Covalent Functionalization of Layered Black Phosphorus by Nucleophilic Reagents
Authors: Sofer Zdeněk , Luxa Jan , Bouša Daniel , Sedmidubský David , Lazar Petr , Hartman Tomáš , Hardtdegen Hilde , Pumera Martin
Published: June 2017

Layered black phosphorus has been attracting great attention due to its interesting material properties which lead to a plethora of proposed applications. Several approaches are demonstrated here for covalent chemical modifications of layered black phosphorus in order to form P−C and P‐O‐C bonds. Nucleophilic reagents are highly effective for chemical modification of black phosphorus. Further derivatization approaches investigated were based on radical reactions. These reagents are not as effective as nucleophilic reagents for the surface covalent modification of black phosphorus. The influence of covalent modification on the electronic structure of black phosphorus was investigated using ab initio calculations. Covalent modification exerts a strong effect on the electronic structure including the change of band‐gap width and spin polarization.
Tuning the Surface Polarity of Microporous Organic Polymers for CO2 Capture
Authors: Chen Jian , Li He , Zhong Mingmei , Yang Qihua
Published: June 2017

CO2 capture is very important to reduce the CO2 concentration in atmosphere. Herein, we report the preparation of microporous polymers with tunable surface polarity for CO2 capture. Porous polymers functionalized with ‐NH2, ‐SO3H, and ‐SO3Li have been successfully prepared by using a post‐synthesis modification of microporous polymers (P‐PhPh3 prepared with 1,3,5‐triphenylbenzene as the monomer and AlCl3 as the catalyst) by chemical transformations, such as nitration–reduction, sulfonation, and cationic exchange. The CO2 adsorption selectivity (CO2/N2 and CO2/H2) and isosteric heats of the microporous polymers increase markedly after modification, P‐PhPh3‐NH2 and P‐PhPh3‐SO3Li afford higher CO2 uptake capacity than P‐PhPh3 at pressures of less than 0.15 bar due to the enhanced interaction between CO2 and the ‐NH2 and ‐SO3Li functional groups. Moreover, functionalized porous polymers could be stably used for CO2 capture. Surface modification is an efficient approach to tune the CO2 capture properties of porous polymers.
Non‐Fragile Simultaneous Actuator and Sensor Fault‐Tolerant Control Design for Markovian Jump Systems Based on Adaptive Observer
Authors: Lu Dunke , Zeng Guohui , Liu Jin
Published: June 2017

In this paper, a non‐fragile fault‐tolerant control strategy is developed for a class of Markovian jump systems against actuator and sensor faults. By taking the sensor fault as an augmented state, the original system is transformed into a descriptor one. Then, an adaptive observer is designed for the descriptor system to simultaneously estimate the states, actuator fault and sensor fault. Moreover, a non‐fragile fault‐tolerant controller is designed to stabilize the resulting closed‐loop system, by using the information of the actuator fault reconstruction. Owing to the non‐fragile property, this controller proves to be highly stable against its intrinsic perturbations. Sufficient conditions of the existence of the designed observer and fault‐tolerant controller are given in terms of linear matrix inequalities. Finally, a practical example of F‐404 aircraft is provided to demonstrate the effectiveness of the proposed method.
Microscale disruption of microorganisms for parallelized process development
Authors: Walther Cornelia , Dürauer Astrid
Published: June 2017

Escherichia coli, Saccharomyces cerevisiae, and Pichia pastoris are the standard platforms for biopharmaceutical production with 40% of all between 2010 to 2014 approved protein drugs produced in those microbial hosts. Typically, products overexpressed E. coli and S. cerevisiae remain in the cytosol or are secreted into the periplasm. Consequently, efficient cell disruption is essential for high product recovery during microbial production. Process development platforms at microscale are essential to shorten time to market. While high‐pressure homogenization is the industry standard for cell disruption at large scale this method is not practicable for experiments in microscale. This review describes microscale methods for cell disruption at scales as low as 200 µL. Strategies for automation, parallelization and miniaturization, as well as comparability of the results at this scale to high pressure homogenization are considered as those criteria decide which methods are most suited for scale down. Those aspects are discussed in detail for protein overexpression in E. coli and yeast but also the relevance for alternative products and host such as microalgae are taken into account. The authors conclude that bead milling is the best comparable microscale method to large scale high‐pressure homogenization and therefore the most suitable technique for automated process development of microbial hosts with the exception of pDNA production.