bluuebunny/crossref_metadata_2025 huggingface dataset:
Substance, Element, Quality, Mixture: Galen’s Physics and His Hippocratic Inheritance
Authors: Hankinson Robert James
Published: December 2017

Galen insists that Hippocrates, in Nature of Man, adopts and argues for a physics in which not only the four fundamental qualities, hot, cold, dry and wet, but also the four basic elements, are taken to be fundamental to the constitution of all material things. He does so because he thinks that such a physics is in fact the right one. The main purpose of this paper is to examine why Galen thinks that not only the fundamental qualities, and a material stuff for them to be instantiated in, is conceptually required for any adequate physics, but also why a commitment to actual elements, conceived of as those material bodies which most fully instantiated the causally basic qualities, is also required. I examine the sources of Galen’s views on material interaction as they derive from their Aristotelian (and to a lesser extent Stoic) forebears, and conclude, ultimately, that Galen’s claim that precise conceptual analysis demands the postulation of actual elements, conceived as the bodies which maximally instantiate the four fundamental qualities, even though no such pure element is ever actually distilled, is in fact unwarranted.
Galien et le visible dans le De elementis : l’usage des couleurs dans la connaissance du vivant
Authors: Luccioni Pascal
Published: December 2017

Galien recourt souvent, dans différents traités et en particulier dans le De elementis, à des exemples de couleurs. Il y a à cela sans doute des raisons d’efficacité rhétorique, ou la volonté de raviver une tradition philosophique antérieure ; mais il en va aussi, pour lui, de l’administration de la preuve. Car les couleurs, en nombre le plus souvent très restreint, correspondent aussi aux quatre humeurs qui constituent le corps humain. On ne peut voir les couleurs du corps que parce que le corps humain excrète, volontairement ou non, les humeurs dont il est constitué.
Τι κατὰ γένος ἕτερον. L’idée d’émergence dans le De elementis de Galien
Authors: Devinant Julien
Published: December 2017

La réponse de Galien au mécanisme épicurien repose sur l’altération qualitative, en charge, selon lui, de rendre compte de l’apparition de phénomènes naturels, notamment vitaux, d’ordre supérieur. Un rapprochement avec la notion contemporaine d’émergence est régulièrement avancé ; mais selon les interprétations, Galien aurait pressenti, adopté ou rejeté une telle position. Dans cet article, nous concentrons l’analyse sur le témoin principal du dossier (De elementis, 3, 7-24). Galien y défend l’idée que l’existence de « quelque chose de génériquement différent » (τι κατὰ γένος ἕτερον) comme la sensibilité suppose au moins l’altérabilité au niveau élémentaire ; mais en quel sens ? Pour le comprendre, nous élargissons l’enquête à l’exploration des relations entre sensation et altération dans d’autres passages du corpus. Nous montrons ensuite que le saut entre les niveaux de réalité est moins ontologique qu’épistémique, ce qui confère d’autant plus de pertinence à la suggestion d’un émergentisme galénique.
De la machine de la fête baroque à la performance urbaine : éphémère éternel
Authors: Cirafici Alessandra
Published: December 2017

L’article interroge l’origine historique du phénomène connu sous le nom d’« architecture éphémère » qui, ayant commencé à se développer à l’époque de la Rome baroque du Bernin, a modelé son expression caractéristique dans la culture et le langage qui ont fait la grandeur de la saison du baroque napolitain grâce à des personnalités telles que Cosimo Fanzago, Ferdinando Sanfelice, Domenico Antonio Vaccaro. Dans ce cadre, notre réflexion portant sur l’importance que la « machine de la fête baroque » a revêtu dans le développement urbain de la ville, la définition de l’espace collectif et la naissance de l’idée même de « place », nous amènera à élargir l’horizon de notre étude sur le spectre de l’architecture, pour réfléchir à la force de renouveau et de persuasion que le « provisoire » est en mesure d’engendrer dans la vie des villes ainsi qu’au rôle que l’« éphémère » – en tant que catégorie pour ainsi dire anthropologique – a joué et continue de jouer dans le développement et dans la définition de l’espace urbain. L’analyse du cas d’étude représenté par l’espace urbain du Largo di Palazzo offrira quelques clés de lecture à propos de la déclinaison du concept d’« éphémère » dans le développement urbain, transposables à partir de l’expérience de la ville de Naples toute entière.
Construction du secteur des hydrocarbures au Québec : entre inertie politique et adaptations instrumentales
Authors: Chailleux Sébastien
Published: December 2017

En analysant les mutations du secteur d’action publique sur les hydrocarbures au Québec, l’article vise à mettre en évidence différentes dimensions du changement. Les transformations et l’inertie institutionnelle sont analysées afin de montrer comment le secteur des hydrocarbures reste marqué par l’incrémentalisme. Toutefois, les ajustements en termes d’instruments et d’acteurs illustrent des dynamiques nouvelles qui ouvrent l’action publique à des enjeux nouveaux. Le changement n’est pas tant insufflé par un choc exogène que par les limites endogènes au secteur et la volonté de les dépasser pour maintenir le système en place.
La participation citoyenne au prisme de la gestion de l’eau. Quel rôle et quelle place pour les Parcs Naturels Régionaux français?
Authors: Ferraton Mélanie , Hobléa Fabien
Published: December 2017

La participation des citoyens à la gestion de l’eau s’impose aujourd’hui non seulement en tant qu’injonction règlementaire, mais aussi comme une profonde aspiration sociale. La mise en œuvre de pratiques participatives, en vertu de la Gestion intégrée de la ressource en eau (GIRE), est désormais partie intégrante de la mission des gestionnaires, ce qui implique de nouveaux modes de gouvernance et de travail. En France, les législations en la matière fixent les lignes directrices de cette approche participative, mais restent très floues sur ses objectifs et les moyens de sa mise en œuvre. Cette ambiguïté laisse une marge de manœuvre considérable aux gestionnaires, mais génère également des incertitudes sur ses tenants et aboutissants. Ainsi, mettre en œuvre la GIRE suppose de composer avec une diversité d’acteurs et d’actions aux formes et objectifs variés. Dans cet article, en analysant le cas de la gestion de l’eau dans les Parcs naturels régionaux (PNR) du Sud-Est français, nous mettons en lumière la complexité de la mise en œuvre de la participation citoyenne. Nous posons alors notre regard sur les réponses des collectivités territoriales pour institutionnaliser la participation, afin de dégager les principaux défis et moyens pour optimiser l’efficience de l’approche participative de la GIRE, à partir du retour d’expérience des PNR.
Simulation of the hydrodynamic behaviour of a Mediterranean reservoir under different climate change and management scenarios
Authors: Prats Jordi , Salençon Marie-José , Gant Magali , Danis Pierre-Alain
Published: December 2017

One of the most important current issues in the management of lakes and reservoirs is the prediction of global climate change effects to determine appropriate mitigation and adaptation actions. In this paper we analyse whether management actions can limit the effects of climate change on water temperatures in a reservoir. For this, we used the model EOLE to simulate the hydrodynamic and thermal behaviour of the reservoir of Bimont (Provence region, France) in the medium term (2036-2065) and in the long term (2066-2095) using regionalised projections by the model CNRM-CERFACS-CNRM-CM5 under the emission scenarios RCP 4.5 and RCP 8.5. Water temperature projections were compared to simulations for the reference period 1993-2013, the longest period for which we had year-long data for both hydrology and meteorology. We calibrated the model using profile measurements for the period 2010-2011 and we carried an extensive validation and assessment of model performance. In fact, we validated the model using profile measurements for 2012-2014, obtaining a root mean square error of 1.08°C and mean bias of -0.11°C, and we assured the consistency of model simulations in the long term by comparing simulated surface temperature to satellite measurements for 1999-2013. We assessed the effect using synthetic input data instead of measured input data by comparing simulations made using both kinds of data for the reference period. Using synthetic data resulted in slightly lower (-0.3°C) average and maximum epilimnion temperatures, a somewhat deeper thermocline, and slightly higher evaporation (+7%). To investigate the effect of different management strategies, we considered three management scenarios: i) bottom outlet and present water level; ii) bottom outlet and elevated water level; and iii) surface outlet and elevated water level. According to the simulations, the reservoir of Bimont will have a low rate of warming of the epilimnion of 0.009-0.024 °C·yr-1, but a rapid hypolimnion warming of 0.013-0.028°C·yr-1. The increase in surface temperatures will augment evaporation. However, the length of the stratification period and the thermocline depth are not expected to change. Elevating the water level and using a surface outlet in the reservoir of Bimont, would result in reductions of surface temperature of a similar magnitude as the expected increase because of climate change.
Total organic carbon and its environmental significance for the surface sediments in groundwater recharged lakes from the Badain Jaran Desert, northwest China
Authors: Dong Shipei , Li Zhuolun , Chen Qiujie , Wei Zhiqiao
Published: December 2017

Total organic carbon (TOC) content in lake sediments is typically used for the reconstruction of paleoenvironments. It remains uncertain, however, whether these sediment variables in lakes supplied by groundwater in the hinterland of the Badain Jaran Desert are applicable. Moreover, it is still uncertain whether the TOC content in these lakes can be used as a proxy to identify past climatic change and environmental evolution studies. In this study, the spatial distributions of the TOC contents and C/N ratios were analyzed for 109 surface sediment samples collected from five lakes without runoff recharge. The results revealed that the TOC content of the lake surface sediments was extremely low (0.03% - 1.01%) and consisted of both allochthonous organic matter carried by wind, as well as autochthonous organic matter generated in the lakes. Within a lake, spatial differences in the amount of TOC found in surface sediments may be caused by several processes including bathymetry topography and wind-induced wave activity. In addition, wind-induced wave activity produces a higher TOC content, which is more pronounced in larger lakes (>0.21 km2) with longer fetches. By contrast, in smaller lakes, organic matter accumulates in the deeper waters, but can be affected by many factors. It is therefore necessary to consider lake area when applying the TOC content of lake sediments for the reconstruction of a paleolake evolution. Furthermore, because the TOC content of lake sediments in hyper-arid regions is extremely low, and the organic matter may have a multiple and varied sources, a single proxy (TOC) cannot be used to reconstruct lake evolution.
Seasonal quantitative dynamics and ecology of pelagic rotifers in an acidified boreal lake
Authors: Wærvågen Svein Birger , Andersen Tom
Published: December 2017

Lake Gjerstadvann is a dimictic, oligotrophic, slightly acidified boreal lake in southern Norway (northwest Europe). The planktonic rotifer community of this lake was studied quantitatively during one year in order to investigate the impacts of the local environment and biotic interactions on seasonal succession and habitat selection. Pure suspension feeders (mainly Keratella spp., Conochilus spp., and Kellicottia longispina) together with raptorial graspers or specialised feeders (mainly Polyarthra spp. and Collotheca spp.) dominated the rotifer community over prolonged periods, whereas carnivorous/omnivorous species (mainly Asplanchna priodonta) were extremely uncommon. Low bicarbonate buffering capacity resulted in a distinctive seasonal oscillating pH between 5.0 and 5.6, defining a special acid-transition lake category. The pH values were highest in the productive period during summer, and lowest during ice break-up coinciding with the peak reactive aluminium concentrations of 250-300 mg L-1. As in typical Norwegian boreal perch lakes, the most abundant cladoceran was Bosmina longispina due to perch predation on the genus Daphnia. Rotifer community structure was significantly related to temperature and oxygen (P=0.001 and P=0.022), illustrating the important effects of the seasonal cycle and vertical density stratification. The most significant competition indicator species were B. longispina and Eudiaptomus gracilis (both with P=0.001). A variance partitioning indicated that 14% of the total community composition variance could only be explained by biotic interactions, while 19% of the variance could be attributed to environmental gradients. Of the variance, 23% could not be resolved between biotic interactions and environmental gradients, while a residual of 44% was not explainable by any of the variables. Acid conditions alone cannot account for all the observed changes in the rotifer community of this lake with low humic content, since resource limitation and food competition are also important factors shaping rotifer population dynamics and the community structure.
Range expansion of the economically important Asiatic blue tick, Rhipicephalus microplus, in South Africa
Authors: Nyangiwe Nkululeko , Horak Ivan G. , Van der Mescht Luther , Matthee Sonja
Published: December 2017

The Asiatic blue tick, Rhipicephalus microplus, a known vector of bovine babesiosis and bovine anaplasmosis, is of great concern in the cattle industry. For this reason, detailed knowledge of the distribution of R. microplus is vital. Currently, R. microplus is believed to be associated mainly with the northern and eastern Savanna and Grassland vegetation in South Africa. The objective of the study was to record the distribution of R. microplus, and the related endemic Rhipicephalus decoloratus, in the central-western region of South Africa that comprises Albany Thicket, Fynbos and Savanna vegetation. In this survey, ticks were collected from 415 cattle in four provinces (Eastern Cape, Northern Cape and Western Cape and Free State provinces) and from the vegetation in the Eastern Cape province of South Africa between October 2013 and September 2015. More than 8000 ticks were collected from cattle at 80 localities of which R. microplus was present at 64 localities and R. decoloratus at 47 localities. A total of 7969 tick larvae were recorded from the vegetation at 20 localities of which 6593 were R. microplus and 1131 were R. decoloratus. Rhipicephalus microplus was recorded in each of the regions that were sampled. Rhipicephalus microplus is now present throughout the coastal region of the Eastern Cape province and at multiple localities in the north-eastern region of the Northern Cape province. It was also recorded in the western region of the Western Cape province and one record was made for the Free State province. The observed range changes may be facilitated by the combined effects of environmental adaptability by the tick and the movement of host animals.
Discrete Schrödinger operators with potentials defined by measurable sampling functions over Liouville torus rotations
Authors: Gordon Alexander Y.
Published: December 2017

We consider a one-dimensional discrete Schrödinger operator

H_\omega=\Delta+v_\omega

whose potential

v_\omega

has the form

v_\omega(j)=V(\omega+j\bar{\alpha}), j\in\mathbb{Z}

. Here

\omega\in\mathbb{T}^k=\mathbb{R}^k/\mathbb{Z}^k,\ \alpha\in\mathbb{R}^k,\ \ \bar{\alpha}

is the projection of

\alpha

on

\mathbb{T}^k

, and the function

V\colon \mathbb{T}^k\to\mathbb{C}

is Borel measurable. We show that if the frequency vector

\alpha

is Liouville (the sequence

\{\nu \bar{\alpha}\}_{\nu\in\mathbb N}

has a subsequence converging to

0

fast enough), then for Lebesgue almost every

\omega\in\mathbb T^k

the point spectrum of the operator

H_\omega

is empty.
Hausdorff dimension of asymptotic self-similar sets
Authors: Wu Daruhan , Yamaguchi Takao
Published: December 2017

In this paper, we introduce the notion of asymptotic self-similar sets on general doubling metric spaces by extending the notion of self-similar sets, and determine their Hausdorff dimensions, which gives an extension of Balogh and Rohner’s result. This is carried out by introducing the notions of almost similarity maps and asymptotic similarity systems. These notions have an advantage of making geometric constructions possible. Actually, as an application, we determined the Hausdorff dimension of general Sierpinski gaskets on complete surfaces constructed by a geometric way in a natural manner.
Предельный закон Пуассона для распределения числа компонент в обобщенной схеме размещения
Authors: Timashev Aleksandr Nikolaevich
Published: December 2017

Рассматриваются вопросы, связанные со сходимостью к предельному закону Пуассона распределений числа компонент заданного объема и общего числа компонент в обобщенной схеме размещения. Найдены достаточные условия такой сходимости. Полученные результаты обобщают известные утверждения, дающие условия пуассоновской сходимости числа компонент (циклов, свободных и корневых деревьев, блоков и других структур) в соответствующих обобщенных схемах размещения.
Критерий совершенной уравновешенности сдвиг-композиции функций над конечным алфавитом
Authors: Logachev Oleg Aleksejevich
Published: December 2017

Доказан критерий совершенной уравновешенности скользящей суперпозиции функций над произвольным конечным алфавитом. Приводятся примеры использования этого результата для построения совершенно уравновешенных функций, не являющихся перестановочными по крайним переменным.
Оценка длины максимального цикла в графе полиномиального преобразования кольца Галуа-Эйзенштейна
Authors: Kozlitin Oleg Alekseevich
Published: December 2017

Исследуются полиномиальные преобразования конечного коммутативного локального кольца главных идеалов (конечного коммутативного цепного кольца, кольца Галуа-Эйзенштейна). Показано, что в классе колец Галуа-Эйзенштейна с равными мощностями и индексами нильпотентности над кольцами Галуа существуют полиномиальные генераторы с периодом выходной последовательности, превышающим периоды выходных последовательностей полиномиальных генераторов над остальными кольцами.
Denrées périssables, froid et qualité des aliments. Cas particulier de la viande
Authors: Rosset Roland
Published: December 2017

La conservation des aliments, notamment des viandes, ne peut se concevoir sans recourir à la réfrigération, mais les modes de vie et les habitudes alimentaires imposent aux denrées fraîches des durées de stockage de plus en plus longues, durées qui devraient logiquement s’accompagner du recours à une température voisine de 0 °C, ce qui dans la pratique n’est pas respecté (température souvent supérieure à 5 °C). Or la contamination par des microorganismes psychrotrophes dégradants ou pathogènes est actuellement inévitable, en sorte que les accidents graves déjà observés et dus aux Salmonella, Listeria, Yersinia,... risquent de se reproduire. Des mesures sévères doivent être prises le long de la chaîne alimentaire, depuis la production jusqu’à la distribution et la consommation. Tous les intervenants, le public y compris, doivent être sensibilisés aux problèmes d’hygiène et de prévention associée à une réfrigération continue à température voisine de 0 °C. Enfin des réfrigérateurs particulièrement performants doivent être proposés au choix des usagers qui veilleront à ne pas prolonger le stockage des denrées, à les soumettre autant que faire ce peut à une cuisson efficace et à pratiquer fréquemment le nettoyage et la désinfection de leurs appareils.
Neuroangiostrongyliasis: The “Subarachnoid Phase” and Its Implications for Anthelminthic Therapy
Authors: Prociv Paul , Turner Megan
Published: December 2017

Infection with the Rat Lungworm Angiostrongylus cantonensis is the leading cause of human eosinophilic meningoencephalitis worldwide. From its origins in southeastern Asia, the parasite was spread extensively throughout the twentieth century and is now established in many of the world’s warmer regions. Its clinical effects range from mild and transient symptoms, usually headache with peripheral nerve dysfunction, to severe and permanent central nervous system (CNS) damage, occasionally fatal. The severity and prognosis of disease are determined by the larval dose, acquired by ingesting infected intermediate hosts (slugs and snails) or, less often, paratenic hosts, such as crabs, shrimps, frogs, and monitor lizards. Early diagnosis is critical for treatment and depends on clinical suspicion, for laboratory confirmation from blood and cerebrospinal fluid can be delayed and unreliable. Treatment is fraught with difficulty, compounded by conflicting published results. Corticosteroids play a useful role in suppressing early CNS inflammation, but their duration for maintenance becomes problematic in severe infections. Because most of the pathogenesis results from host immuno-inflammatory responses to migrating and dead larvae in the CNS, anthelminthic therapy remains controversial: if effective, it kills viable larvae, arresting them in the CNS and so exacerbating the pathology. In human infections, it is now clear that many larvae do leave the CNS and reach the pulmonary arteries, sometimes with clinical consequences. Pioneering life-cycle studies in rats demonstrated a “subarachnoid phase” in larval development and migration; recent autopsy findings, outlined here, show it also occurs in humans and has some bearing on treatment. One new and four previously reported cases of human infection are analyzed here, with findings indicating that anthelminthic treatment is effective only when given early and should not be commenced beyond 3 weeks after exposure to infection. In endemic areas, treatment should start as soon as this infection is suspected, even without a clear history of exposure, given the unacceptable risks of waiting for diagnostic laboratory confirmation.
Neurocysticercosis among People Living Near Pigs Heavily Infected with Cysticercosis in Rural Endemic Peru
Authors: Garvey Brian T. , Moyano Luz M. , Ayvar Viterbo , Rodriguez Silvia , Gilman Robert H. , Gonzalez Armando E. , Garcia Hector H. , O’Neal Seth E. , _ _
Published: December 2017

Neurocysticercosis causes substantial neurologic morbidity in endemic regions around the world. In this cross-sectional study, we describe the frequency of neurocysticercosis among a presumed high-risk group of people in an endemic community in northern Peru. Participants who screened positive on a nine-question seizure survey were evaluated clinically to diagnose epilepsy using International League Against Epilepsy criteria. Those with epilepsy were offered a noncontrast computerized tomography (CT) of the head. We also tested sera from all participants using the lentil lectin-bound glycoprotein enzyme-linked immunoelectrotransfer blot (EITB) to detect anti-cysticercus antibodies and enzyme-linked immunosorbent assay (ELISA) B60/B158 to detect cysticercosis antigens. Participants with strongly positive ELISA (ratio ≥ 3) were offered a noncontrast magnetic resonance imaging (MRI) of the brain. We diagnosed 16 cases of epilepsy among 527 people screened (lifetime prevalence 30 per 1,000). Twelve with epilepsy accepted CT scan and five (41.7%) had parenchymal calcifications. None had viable cysts. Of the 514 who provided a blood sample, 241 (46.9%) were seropositive by EITB and 12 (2.9%) were strongly positive by ELISA (ratio ≥ 3). Eleven accepted MRI and eight (72.3%) had neurocysticercosis, including five with extraparenchymal cysts, five with parenchymal vesicular cysts, and two with parenchymal granulomas. These findings show that clinically relevant forms of neurocysticercosis and epilepsy can be found by applying screening interventions in communities endemic to Taenia solium. Longitudinal controlled studies are needed to better understand which subgroups are at highest risk and which are most likely to have improved prognosis as a result of screening.
Congenital Transmission of Trypanosoma cruzi in Argentina, Honduras, and Mexico: An Observational Prospective Study
Authors: Buekens Pierre , Cafferata María Luisa , Alger Jackeline , Althabe Fernando , Belizán José M. , Bustamante Norma , Carlier Yves , Ciganda Alvaro , del Cid Jaime H. , Dumonteil Eric , Gamboa-León Rubí , García Jorge A. , Gibbons Luz , Graiff Olga , Maldonado Jesús Gurubel , Herrera Claudia , Howard Elizabeth , Lara Laura Susana , López Benjamín , Matute María Luisa , Ramírez-Sierra María Jesús , Robles María Cecilia , Sosa-Estani Sergio , Truyens Carine , Valladares Christian , Wesson Dawn M. , Zúniga Concepción , _ _
Published: December 2017

Compared with South America, there is a lack of epidemiologic studies about the risk of congenital transmission of Trypanosoma cruzi in Central America and Mexico. It has been suggested that T. cruzi genotypes might differ by region and that congenital transmission might vary according to the parasite’s genotype. Our objective was to compare T. cruzi congenital transmission rates in three countries. We performed an observational prospective study in 2011–2014 enrolling women at delivery in one hospital in Argentina, two hospitals in Honduras, and two hospitals in Mexico. Congenital T. cruzi infection was defined as the presence of one or more of the following criteria: presence of parasites in cord blood (direct parasitological microscopic examination) with positive polymerase chain reaction (PCR) in cord blood, presence of parasites in infant’s blood at 4–8 weeks (direct parasitological microscopic examination), and persistence of T. cruzi-specific antibodies at 10 months, as measured by at least two tests. Among 28,145 enrolled women, 347 had at least one antibody rapid test positive in cord blood and a positive enzyme-linked immunosorbent assay in maternal blood. PCR in maternal blood was positive in 73.2% of the cases, and genotyping identified a majority of non-TcI in the three countries. We found no (0.0%; 95% confidence interval [CI]: 0.0, 2.0) confirmed congenital case in Honduras. Congenital transmission was 6.6% (95% CI: 3.1, 12.2) in Argentina and 6.3% (95% CI: 0.8, 20.8) in Mexico. Trypanosoma cruzi non-TcI predominated and risks of congenital transmission were similar in Argentina and Mexico.
Potencial de las imágenes UAV como datos de verdad terreno para la clasificación de la severidad de quema de imágenes Landsat: aproximaciones a un producto útil para la gestión post incendio
Authors: Pla M. , Duane A. , Brotons L.
Published: December 2017

Mapping fire severity is determinant to understand landscape evolution after a wildfire and provides useful information for decision making during post fire management. Quantitative fire severity mapping from relative changes in Normalized Burn Ratio index (RdNBR) is not actually being incorporated into decision making processes, being more useful the categorization in severity levels (high, moderate and low). However, the most common mapping severity methodologies based on the definition of RdNBR thresholds from field information are not always possible due to lack of field data or because the published thresholds are unsatisfactory in new regions. The boom in the use of UAVs (Unmanned Aerial Vehicle) has raised these platforms as potential tools for validation of remote sensing data. This paper presents the potential of UAVs as ground truth information in forest fires. From the photointerpretation of high resolution RGB images, the Aerial Severity Proportion Index (ASPI) has been created. Non-linear regression models between RdNBR and ASPI allows to delimitate of thresholds for the classification of Landsat images and to obtain qualitative severity maps. Validation with random points presents a kappa index of 0,5 and a relative accuracy of 70,8%. Therefore, UAV images become a very useful tool for wildfire severity mapping and for fill the gap between remote sensing information and expensive field ground campaigns
Estimación de la severidad en incendios forestales a partir de datos LiDAR-PNOA y valores de Composite Burn Index
Authors: Montealegre A. L. , Lamelas M. T. , Tanase M. A. , De la Riva J.
Published: December 2017

Mediterranean pine forests in Spain experience wildland fire events with different frequencies, intensities, and severities. An estimation of the fire severity as accurate as possible is required by forest managers to decide which strategy is most appropriate to mitigate the effect of fire. The aim of this research is to estimate the post-fire severity, relating a pool of independent variables derived from the LiDAR (Light Detection And Ranging) points clouds delivered by the National Plan for Aerial Orthophotography (PNOA) to field data based on Composite Burn Index collected in four fires located in Aragón (Spain). Logistic regression models were developed and statistically tested and validated to map fire severity with up to 85.5% accuracy. The canopy relief ratio and the percentage of all returns above one meter height were the most significant variables. In addition, the obtained results are compared to different spectral indices derived from Landsat Thematic Mapper.
Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols
Authors: Chim Man Mei , Cheng Chiu Tung , Davies James F. , Berkemeier Thomas , Shiraiwa Manabu , Zuend Andreas , Chan Man Nin
Published: December 2017

Abstract. Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C5H8O4) droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C5) hydroxyl functionalization product (C5H8O5) and a C4 fragmentation product (C4H6O3). These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon–carbon bond scission) of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model) coupled with the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from 0.362 to 0.424; however, the diameter of the droplets decreases by 6.1 %. This can be attributed to the formation of volatile fragmentation products that partition to the gas phase, leading to a net loss of organic species and associated particle-phase water, and thus a smaller droplet size. Overall, fragmentation and volatilization processes play a larger role than the functionalization process in determining the evolution of aerosol water content and droplet size at high-oxidation stages.
Spatial and Temporal Variability of Interhemispheric Transport Times
Authors: Wu Xiaokang , Yang Huang , Waugh Darryn W. , Orbe Clara , Tilmes Simone , Lamarque Jean-Francois
Published: December 2017

Abstract. The seasonal and interannual variability of transport times from the northern mid-latitude surface into the southern hemisphere is examined using simulations of three idealized age tracers: A ideal age tracer that yields the mean transit time from northern mid-latitudes and two tracers with uniform 50-day and 5-day decay. For all tracers the largest seasonal and interannual variability occurs near the surface within the tropics, and is generally closely coupled to movement of the intertropical convergence zones (ITCZ). There are, however, notable differences in variability between different tracers. The largest seasonal and interannual variability in the mean age is generally confined to latitudes spanning the ITCZ, with very weak variability in the southern extratropics. In contrast, for tracers subject to spatially uniform exponential loss the peak variability tends to be south of the ITCZ, and there is a smaller contrast between tropical and extratropical variability. These differences in variability occur because the distribution of transit time from northern mid-latitudes is very broad and tracers with more rapid loss are more sensitive to changes in fast time scales than the mean age tracer. These simulations suggest that the seasonal/interannual variability in the southern extratropics of trace gases, with predominantly NH mid-latitude sources, may differ depending on the gases' chemical lifetimes.
The atmospheric impacts of monoterpene ozonolysis on global stabilised Criegee intermediate budgets and SO2 oxidation: experiment, theory and modelling
Authors: Newland Mike J. , Rickard Andrew R. , Sherwen Tomás , Evans Mathew J. , Vereecken Luc , Muñoz Amalia , Ródenas Milagros , Bloss William J.
Published: December 2017

Abstract. The gas-phase reaction of alkenes with ozone is known to produce stabilised Criegee intermediates (SCIs). These biradical/zwitterionic species have the potential to act as atmospheric oxidants for trace pollutants such as SO2, enhancing the formation of sulfate aerosol with impacts on air quality and health, radiative transfer and climate. However, the importance of this chemistry is uncertain as a consequence of limited understanding of the abundance and atmospheric fate of SCIs. In this work we apply experimental, theoretical and numerical modelling methods to quantify the atmospheric impacts, abundance, and fate, of the structurally diverse SCIs derived from the ozonolysis of monoterpenes, the second most abundant group of unsaturated hydrocarbons in the atmosphere. We have investigated the removal of SO2 by SCI formed from the ozonolysis of three monoterpenes (-pinene, -pinene and limonene) in the presence of varying amounts of water vapour in large-scale simulation chamber experiments. The SO2 removal displays a clear dependence on water vapour concentration, but this dependence is not linear across the range of [H2O] explored. At low [H2O] a strong dependence of SO2 removal on [H2O] is observed, while at higher [H2O] this dependence becomes much weaker. This is interpreted as being caused by the production of a variety of structurally (and hence chemically) different SCI in each of the systems studied, each displaying different rates of reaction with water and of unimolecular rearrangement/decomposition. The determined rate constants, k(SCI+H2O), for those SCI that react primarily with H2O range from 4–310 × 10−15 cm3 s−1. For those SCI that predominantly react unimolecularly, determined rates range from 130–240 s−1. These values are in line with previous results for the (analogous) stereo-specific SCI system of syn/anti-CH3CHOO. The experimental results are interpreted through theoretical studies of the SCI unimolecular reactions and bimolecular reactions with H2O, characterised for -pinene and -pinene at the M06-2X/aug-cc-pVTZ level of theory. The theoretically derived rates agree with the experimental results within the uncertainties. A global modelling study, applying the experimental results within the GEOS-Chem chemical transport model, suggests that > 98 % of the total monoterpene derived global SCI burden is comprised of SCI whose structure determines that they react slowly with water, and whose atmospheric fate is dominated by unimolecular reactions. Seasonally averaged boundary layer concentrations of monoterpene-derived SCI reach up to 1.2 × 104 cm−3 in regions of elevated monoterpene emissions in the tropics. Reactions of monoterpene derived SCI with SO2 account for
Development and application of a backscatter lidar forward operator for quantitative validation of aerosol dispersion models and future data assimilation
Authors: Geisinger Armin , Behrendt Andreas , Wulfmeyer Volker , Strohbach Jens , Förstner Jochen , Potthast Roland
Published: December 2017

Abstract. A new backscatter lidar forward operator was developed which is based on the distinct calculation of the aerosols' backscatter and extinction properties. The forward operator was adapted to the COSMO-ART ash dispersion simulation of the Eyjafjallajökull eruption in 2010. While the particle number concentration was provided as a model output variable, the scattering properties of each individual particle type were determined by dedicated scattering calculations. Sensitivity studies were performed to estimate the uncertainties related to the assumed particle properties. Scattering calculations for several types of non-spherical particles required the usage of T-matrix routines. Due to the distinct calculation of the backscatter and extinction properties of the models' volcanic ash size classes, the sensitivity studies could be made for each size class individually, which is not the case for forward models based on a fixed lidar ratio. Finally, the forward-modeled lidar profiles have been compared to automated ceilometer lidar (ACL) measurements both qualitatively and quantitatively while the attenuated backscatter coefficient was chosen as a suitable physical quantity. As the ACL measurements were not calibrated automatically, their calibration had to be performed using satellite lidar and ground-based Raman lidar measurements. A slight overestimation of the model-predicted volcanic ash number density was observed. Major requirements for future data assimilation of data from ACL have been identified, namely, the availability of calibrated lidar measurement data, a scattering database for atmospheric aerosols, a better representation and coverage of aerosols by the ash dispersion model, and more investigation in backscatter lidar forward operators which calculate the backscatter coefficient directly for each individual aerosol type. The introduced forward operator offers the flexibility to be adapted to a multitude of model systems and measurement setups.
The water vapor self-continuum absorption in the infrared atmospheric windows:
New laser measurements near 3.3 μm and 2.0 μm
Authors: Lechevallier Loic , Vasilchenko Semen , Grilli Roberto , Mondelain Didier , Romanini Daniele , Campargue Alain
Published: December 2017

Abstract. The amplitude, the temperature dependence and the physical origin of the water vapor absorption continuum are a long standing issue in molecular spectroscopy with direct impact in atmospheric and planetary sciences. In the recent years, we have determined the self-continuum absorption of water vapor at different spectral points of the atmospheric windows at 4.0, 2.1, 1.6 and 1.25 μm, by highly sensitive cavity enhanced laser techniques. These accurate experimental constraints have been used to adjust the last version (V3.2) of the semi-empirical MT_CKD model (Mlawer–Tobin_Clough–Kneizys–Davies) widely incorporated in atmospheric radiative transfer codes. In the present work, the self-continuum cross-sections, CS, are newly determined at 3.3 μm (3007 cm−1) and 2.0 μm (5000 cm−1) by optical-feedback-cavity enhanced absorption spectroscopy (OFCEAS) and cavity ring-down spectroscopy (CRDS), respectively. These new data allow completing the spectral coverage of the 4.0 and 2.1 μm windows, respectively, and testing the recently released V3.2 version of the MT_CKD3 continuum. By complementing high temperature literature data to the present data, the temperature dependence of the self continuum is presented. 1 Institute of Engineering Univ. Grenoble Alpes
Response of hydrology and CO2 flux to experimentally-altered rainfall frequency in a temperate poor fen, southern Ontario, Canada
Authors: Radu Danielle D. , Duval Tim P.
Published: December 2017

Abstract. Predicted changes to the precipitation regime in many parts of the world include intensifying the distribution into lower frequency, large magnitude events. The corresponding alterations to the soil moisture regime may affect plant growth and soil respiration, particularly in peatlands, where large stores of organic carbon are due to gross ecosystem productivity (GEP) exceeding ecosystem respiration (ER). This study uses a combined lab and field approach to examine the effect of changing rainfall frequency on peatland moisture controls on CO2 uptake in an undisturbed cool temperate poor fen. Lab monoliths and field plots containing mosses, sedges, or shrubs received either 2.3, 1, or 0.5 events per week, with total rainfall held constant. Decreasing rain frequency led to lower near-surface volumetric moisture content (VMC), water table (WT), and soil tension for all vegetation types, with minimal effect on evapotranspiration. The presence of sedges in particular led to soil tensions > −100 cm of water of a sizeable duration (37 %) of the experiment. Altered rainfall frequencies affected GEP but had little effect on ER: overall low-frequency rain led to reduced net CO2 uptake for all three vegetation types. VMC had a strong control on GEP and net ecosystem exchange (NEE) of the Sphagnum capillifolium monoliths, and decreasing rainfall frequency influenced these relationships. Overall, communities dominated by mosses became net sources of CO2 after three days without rain, whereas sedge communities remained net sinks for up to 14 days without rain. Results of this study demonstrate the hydrological controls of peatland CO2 exchange dynamics influenced by changing precipitation frequency and suggest these predicted changes in frequency will lead to increased vascular plant growth and limit the carbon-sink function of peatlands.
Oligocene–Miocene paleoceanography off the Wilkes Land Margin (East Antarctica) based on organic-walled dinoflagellate cysts
Authors: Bijl Peter K. , Houben Alexander J. P. , Hartman Julian D. , Pross Jörg , Salabarnada Ariadna , Escutia Carlota , Sangiorgi Francesca
Published: December 2017

Abstract. Next to atmospheric CO2 concentrations, oceanographic conditions are a critical factor determining the stability of Antarctic marine-terminating ice sheets. The Oligocene and Miocene epochs (~ 34–5 Ma) were time intervals with atmospheric CO2 concentrations between those of present-day and those expected for the near future. As such, these time intervals may bear information to resolve the uncertainties that still exist in the projection of future ice-sheet volume decline. We present organic-walled dinoflagellate cyst (dinocyst) assemblages from chronostratigraphically well-constrained Oligocene to mid-Miocene sediments from Integrated Ocean Drilling Program Expedition (IODP) Site U1356. Situated offshore the Wilkes Land continental margin, East Antarctica, the sediment core has archived past dynamics of an ice sheet that is today mostly grounded below sea level. We interpret dinocyst assemblages in terms of paleoceanographic change on different time scales, i.e., on glacial-interglacial and long-term variability. Sea-ice indicators occur only for the first 1.5 Ma following the full Antarctic continental glaciation during the early Oligocene, and after the Middle Miocene Climatic Optimum. During the remainder of the Oligocene and Miocene dinocysts suggest a weaker-than-modern sea-ice season. The assemblages generally bear strong similarity to present-day open-ocean, high-nutrient settings north of the sea ice edge, with episodic dominance of temperate species similar to the present-day subtropical front. Oligotrophic and temperate surface waters prevailed over the site notably during interglacial time intervals, suggesting that the position of the (subpolar) oceanic frontal systems have varied in concordance with Oligocene-Miocene glacial-interglacial climate variability.
Late Oligocene obliquity-paced contourite sedimentation in the Wilkes Land
margin of East Antarctica: implications for paleoceanographic and ice sheet
configurations
Authors: Salabarnada Ariadna , Escutia Carlota , Röhl Ursula , Nelson C. Hans , McKay Robert , Jiménez-Espejo Francisco F. , Bijl Peter K. , Hartman Julian D. , Ikehara Minoru , Strother Stephanie L. , Salzmann Ulrich , Evangelinos Dimitris , López-Quirós Adrián , Flores José Abel , Sangiorgi Francesca , Brinkhuis Henk
Published: December 2017

Abstract. The late Oligocene experienced atmospheric concentrations of CO2 between 400 and 750 ppm, which are within the IPCC projections for this century, assuming unabated CO2 emissions. However, Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved, but are important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under such CO2 scenarios. Here, we present late Oligocene (26–25 Ma) ice sheet and paleoceanographic reconstructions recorded in sediments recovered by IODP Site U1356, offshore of the Wilkes Land margin in East Antarctica. Our study, based on a combination of sediment facies analysis, physical properties, and geochemical parameters, shows that glacial and interglacial sediments are continuously reworked by bottom-currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted to represent a northward shift of westerly winds and surface oceanic fronts. During interglacial times, more oxygenated and ventilated conditions prevailed, which suggests enhanced mixing of the water masses with enhanced current velocities. Micritic limestone intervals within some of the interglacial facies represent warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g. North Atlantic sourced deep water) had a greater influence on the site. The lack of iceberg rafted debris (IRD) throughout the studied interval contrasts with early Oligocene and post-Oligocene sections from Site U1356 and with late Oligocene strata from the Ross Sea (CRP and DSDP 270), which contain IRD and evidence for coastal sea ice and glaciers. These observations, supported by elevated paleotemperatures and the absence of sea-ice, suggest that between 26 and 25 Ma reduced glaciers or ice caps occupied the terrestrial lowlands of the Wilkes Land margin. Unlike today, the continental shelf was not over-deepened, and thus marine-based ice sheet expansion was likely limited to coastal regions. Combined, these data suggest that ice sheets in the Wilkes Subglacial Basin were largely land-based, and therefore retreated as a consequence of surface melt during late Oligocene, rather than direct ocean forcing and marine ice sheet instability processes as it did in younger past warm intervals. Spectral analysis on late Oligocene sediments from the eastern Wilkes Land margin show that the glacial-interglacial cyclicity and resulting displacements of the Southern Ocean frontal systems between 26–25 Ma were forced by obliquity.