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Journal articles on the topic 'Earth divers'
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1
Tauveron, Albert. "Jeux Divers... impressions." Revue de géographie alpine 79, no. 3 (1991): 125–26. http://dx.doi.org/10.3406/rga.1991.3620.
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O'Mack, Scott. "Yacateuctli and Ehecatl-Quetzalcoatl: Earth-Divers in Aztec Central Mexico." Ethnohistory 38, no. 1 (1991): 1. http://dx.doi.org/10.2307/482789.
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Grządziel, Artur. "Results from Developments in the Use of a Scanning Sonar to Support Diving Operations from a Rescue Ship." Remote Sensing 12, no. 4 (February 20, 2020): 693. http://dx.doi.org/10.3390/rs12040693.
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In recent years, widespread use of scanning sonars for acoustic imaging of the seabed surface can be observed. These types of sonars are mainly used with tripods or special booms, or are mounted onboard remotely operated or unmanned vehicles. Typical scanning sonar applications include search and recovery operations, imaging of underwater infrastructure, and scour monitoring. The use of these sonars is often limited to shallow waters. Diver teams or underwater remotely operated vehicles (ROV) are commonly used to inspect shipwrecks, port wharfs, and ship hulls. However, reduced underwater visibility, submerged debris, and extreme water depths can limit divers’ capabilities. In this paper, a novel, nonstandard technique for use of a scanning sonar is proposed. The new application for scanning sonar technology is a practical solution developed on the Polish Navy’s search and rescue ship “Lech.” To verify the effectiveness of the proposed technique, the author took part in four different studies carried out in the southeastern Baltic Sea. The tests were performed using the MS 1000 scanning sonar. The results demonstrate that the proposed technique has the potential to provide detailed sonar images of the seabed and underwater objects before the descent of divers. The divers get acquainted with the underwater situation, which undoubtedly increases the safety of the entire operation. Scanning sonars are unlikely to completely replace the work of divers but may reduce the number and duration of dives. The sonar use technique turned out to be useful when rescuing a crew of a submarine that crashed and settled on the sea bottom as part of a naval exercise. The sonar data obtained during four experimental tests performed in the Baltic Sea prove the validity, usefulness, and significance of the proposed technique, especially from the standpoint of safety of underwater work.
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Mangeruga, Marino, Alessandro Casavola, Francesco Pupo, and Fabio Bruno. "An Underwater Pathfinding Algorithm for Optimised Planning of Survey Dives." Remote Sensing 12, no. 23 (December 4, 2020): 3974. http://dx.doi.org/10.3390/rs12233974.
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In scientific and technical diving, the survey of unknown or partially unexplored areas is a common task that requires an accurate planning for ensuring the optimal use of resources and the divers’ safety. In particular, in any kind of diving activity, it is essential to foresee the “dive profile” that represents the diver’s exposure to pressure over time, ensuring that the dive plan complies with the specific safety rules that have to be applied in accordance with the diver’s qualification and the environmental conditions. This paper presents a novel approach to dive planning based on an original underwater pathfinding algorithm that computes the best 3D path to follow during the dive in order to be able to maximise the number of points of interest (POIs) visited, while taking into account the safety limitations. The proposed approach, for the first time, considers the morphology of the 3D space in which the dive takes place to compute the best path, taking into account the decompression limits and avoiding the obstacles through the analysis of a 3D map of the site. Moreover, three different cost functions are proposed and evaluated to identify the one that could suit the divers’ needs better.
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Nocerino, Erica, Fabio Menna, Armin Gruen, Matthias Troyer, Alessandro Capra, Cristina Castagnetti, Paolo Rossi, Andrew J. Brooks, Russell J. Schmitt, and Sally J. Holbrook. "Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying." Remote Sensing 12, no. 18 (September 17, 2020): 3036. http://dx.doi.org/10.3390/rs12183036.
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Underwater photogrammetry is increasingly being used by marine ecologists because of its ability to produce accurate, spatially detailed, non-destructive measurements of benthic communities, coupled with affordability and ease of use. However, independent quality control, rigorous imaging system set-up, optimal geometry design and a strict modeling of the imaging process are essential to achieving a high degree of measurable accuracy and resolution. If a proper photogrammetric approach that enables the formal description of the propagation of measurement error and modeling uncertainties is not undertaken, statements regarding the statistical significance of the results are limited. In this paper, we tackle these critical topics, based on the experience gained in the Moorea Island Digital Ecosystem Avatar (IDEA) project, where we have developed a rigorous underwater photogrammetric pipeline for coral reef monitoring and change detection. Here, we discuss the need for a permanent, underwater geodetic network, which serves to define a temporally stable reference datum and a check for the time series of photogrammetrically derived three-dimensional (3D) models of the reef structure. We present a methodology to evaluate the suitability of several underwater camera systems for photogrammetric and multi-temporal monitoring purposes and stress the importance of camera network geometry to minimize the deformations of photogrammetrically derived 3D reef models. Finally, we incorporate the measurement and modeling uncertainties of the full photogrammetric process into a simple and flexible framework for detecting statistically significant changes among a time series of models.
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Lamers, Machiel, and Hans Gelter. "Diversification of Antarctic tourism: the case of a scuba diving expedition." Polar Record 48, no. 3 (July 12, 2011): 280–90. http://dx.doi.org/10.1017/s0032247411000246.
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ABSTRACTTourism in Antarctica has grown substantially over recent decades and has diversified into different activities and modes of transport. This paper presents a first attempt to explore the implications of this diversification trend for Antarctic tourist experiences, wildlife and onsite management. Evidence from a passenger survey, participatory observations and expert interviews using video elicitation has been collected during, and in the context of, a diving expedition cruise. The data suggests that significant differences can be detected in the way divers and non-divers experience aspects of the trip, most notably regarding guides. The results also indicate that diverse activities generate a broader variance in attitudes and behaviours, which may have repercussions for wildlife, site use and onsite management. Given the diversification trend it is timely and necessary to revisit and consistently enforce site guidelines and visitor guidelines with an eye on multi-activity trips. In addition, further studies on the implications of this trend are needed by means of case studies, surveys looking at a wider range of tourist trips, and monitoring programmes assessing wildlife behaviour and impacts.
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Lang, J., A. Pascal, and J. Salomon. "Petrographical study of continental Holocene carbonates in the French Jura (Artois, Chalain and Dortan)." Zeitschrift für Geomorphologie 36, no. 3 (October 2, 1992): 273–91. http://dx.doi.org/10.1127/zfg/36/1992/273.
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Gouin-Lévêque, Pascale. "Le Pays du Perche : pertinence et enjeux de divers espaces de références." Norois 181, no. 1 (1999): 91–99. http://dx.doi.org/10.3406/noroi.1999.6924.
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Simard, Myriam. "Environnement, conflits et tractations entre divers acteurs ruraux au Québec : une mobilisation inégale du capital environnemental ?" Norois, no. 243 (November 2, 2017): 111–26. http://dx.doi.org/10.4000/norois.6111.
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Goel, Rajeev, Binny Mahendru, and Tushar Saini. "Marine natural products: the new generation of pharmacotherapeutics." International Journal of Basic & Clinical Pharmacology 10, no. 7 (June 22, 2021): 876. http://dx.doi.org/10.18203/2319-2003.ijbcp20212389.
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The biomedical potential of the sea has gone largely unexplored so far, despite the fact that it covers three quarters of the planet surface and the fact that life on Earth originated from the sea. However, with the arrival of the professional deep sea divers, the marine researchers have gained access to all sorts of marine creatures like sponges, corals, sea urchins, sea squirts, hydroids, sea anemones, fishes and mollusks as well as to varied types of sea plants including algae and the other micro-organisms embedded in the sea bed. The biomedical scientists are exploiting these all to extract marine natural products (MNPs) having pharmacological properties that may one day cure long list of illnesses varying from bacterial infections to cancer, Alzheimer's and AIDS and was the focus of this review article.
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Ghaffarian, S., and S. Ghaffarian. "Automatic Building Detection based on Supervised Classification using High Resolution Google Earth Images." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3 (August 11, 2014): 101–6. http://dx.doi.org/10.5194/isprsarchives-xl-3-101-2014.
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This paper presents a novel approach to detect the buildings by automization of the training area collecting stage for supervised classification. The method based on the fact that a 3d building structure should cast a shadow under suitable imaging conditions. Therefore, the methodology begins with the detection and masking out the shadow areas using luminance component of the LAB color space, which indicates the lightness of the image, and a novel double thresholding technique. Further, the training areas for supervised classification are selected by automatically determining a buffer zone on each building whose shadow is detected by using the shadow shape and the sun illumination direction. Thereafter, by calculating the statistic values of each buffer zone which is collected from the building areas the Improved Parallelepiped Supervised Classification is executed to detect the buildings. Standard deviation thresholding applied to the Parallelepiped classification method to improve its accuracy. Finally, simple morphological operations conducted for releasing the noises and increasing the accuracy of the results. The experiments were performed on set of high resolution Google Earth images. The performance of the proposed approach was assessed by comparing the results of the proposed approach with the reference data by using well-known quality measurements (Precision, Recall and F1-score) to evaluate the pixel-based and object-based performances of the proposed approach. Evaluation of the results illustrates that buildings detected from dense and suburban districts with divers characteristics and color combinations using our proposed method have 88.4 % and 853 % overall pixel-based and object-based precision performances, respectively.
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Bork, Kennard. "Elie Bertrand (1713-1797) Sees God's Order in Nature's Record: The 1766 Recueil De Divers Traites Sur L'Historie Naturelle." Earth Sciences History 10, no. 1 (January 1, 1991): 73–88. http://dx.doi.org/10.17704/eshi.10.1.r57841j64602671r.
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Elie Bertrand (1713-1797) was a Swiss pastor/naturalist whose geological writings are illustrative of the growth of eighteenth-century natural history. Describing, cataloguing, and classifying formed the core of his work, but he also proposed theoretical analyses based on observations in the field. Bertrand's intellectual roots included Cartesian rationalism, British natural theology, and the Linnacan system of classification. Trained as a theologian. Bertrand viewed the physical world as a proving ground for showing God's Wise Design in nature. He was also committed to empiricism, and repeatedly called for expanding the base of geological knowledge.Several of the published products of Bertrand's attempts to understand the natural world were brought together in the 1766 Recueil de divers traités sur l'histoire naturelle. By briefly considering each of the incorporated papers, it is possible to recognize the topics which interested eighteenth-century naturalists and to develop insight into the methodologies they used. In the Recueil we see Bertrand's eclectic epistemology attempt to deal with such topics as the interior of the earth, earthquakes, fossils, and the origin and Providential use of mountains.Celebrated in his day, Bertrand was a correspondent of Voltaire, a counselor to the Polish court, and a member of numerous learned societies. He published articles in the French Encyclopédic, and his 1763 Dictionnaire universal des fossiles was among the most-read scientific books of the century. The obscurity which enveloped Elie Bertrand seems related in large part to the fact that he was an accumulator of data and a commentator about past theories, rather than an innovator of new concepts. As the natural theology that undergirded his writing became obsolete, the cogency of his arguments diminished. In the context of his time, however, Bertrand is an instructive example of how geoscience matured during what has been termed a sterile period in the development of natural history.
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Ferrero Carracedo, Luis. "Ecos derrideanos leyendo el "Ulises" de Joyce." Tropelías: Revista de Teoría de la Literatura y Literatura Comparada, no. 19 (May 27, 2013): 18. http://dx.doi.org/10.26754/ojs_tropelias/tropelias.201319712.
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La lectura del Ulises de Joyce hace resonar en la mente del lector ecos múltiples de las lecturas de Glas, de Circonfession, de Parages, entre otras obras de Derrida. La deconstrucción del cristianismo a partir de una teología de los restos nos introduce en temas nucleares tanto en Joyce como en Derrida (la ma(d)r(e), la relación cielo/tierra, padre/hijo, paternidad/maternidad), afirmando un entreser espectral en un mundo de postcreación. Reading of James Joyce’s Ulysses brings to reader’s mind a lot of divers echoes of Glas and Circonfession and Parages, among other Derrida’s works. The Christianity deconstruction through a remains theology introduce us into the nuclear matters both in Joyce and Derrida (the mother/sea, the relation between heaven and earth, father and son, maternity and paternity), that unveil a ghostly being-between within a post-creation world.
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Schmid, M. O., S. Gubler, J. Fiddes, and S. Gruber. "Inferring snow pack ripening and melt out from distributed ground surface temperature measurements." Cryosphere Discussions 6, no. 1 (February 10, 2012): 563–91. http://dx.doi.org/10.5194/tcd-6-563-2012.
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Abstract. The seasonal snow cover and its melting are heterogeneous both in space and time. Describing and modelling this variability are important because it affects divers phenomena such as runoff, ground temperatures or slope movements. This study investigates the derivation of melting characteristics based on spatial clusters of temperature measurements. Results are based on data from Switzerland where ground surface temperatures were measured with miniature loggers (iButtons) at 40 locations, referred to as footprints. At each footprint, ten iButtons have been distributed randomly few cm below the ground surface over an area of 10 m × 10 m. Footprints span elevations of 2100–3300 m a.s.l. and slope angles of 0–55°, as well as diverse slope expositions and types of surface cover and ground material. Based on two years of temperature data, the basal ripening date and the melt-out date are determined for each iButton, aggregated to the footprint level and further analysed. The date of melt out could be derived for nearly all iButtons, the ripening date could be extracted for only approximately half of them because it requires ground freezing below the snow pack. The variability within a footprint is often considerable and one to three weeks difference between melting or ripening of the points in one footprint is not uncommon. The correlation of mean annual ground surface temperatures, ripening date and melt-out date is moderate, making them useful intuitive complementary measured for model evaluation.
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Čejka, Jan, Fabio Bruno, Dimitrios Skarlatos, and Fotis Liarokapis. "Detecting Square Markers in Underwater Environments." Remote Sensing 11, no. 4 (February 23, 2019): 459. http://dx.doi.org/10.3390/rs11040459.
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Augmented reality can be deployed in various application domains, such as enhancing human vision, manufacturing, medicine, military, entertainment, and archeology. One of the least explored areas is the underwater environment. The main benefit of augmented reality in these environments is that it can help divers navigate to points of interest or present interesting information about archaeological and touristic sites (e.g., ruins of buildings, shipwrecks). However, the harsh sea environment affects computer vision algorithms and complicates the detection of objects, which is essential for augmented reality. This paper presents a new algorithm for the detection of fiducial markers that is tailored to underwater environments. It also proposes a method that generates synthetic images with such markers in these environments. This new detector is compared with existing solutions using synthetic images and images taken in the real world, showing that it performs better than other detectors: it finds more markers than faster algorithms and runs faster than robust algorithms that detect the same amount of markers.
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Torma, Franziska. "Frontiers of Visibility." Transfers 3, no. 2 (June 1, 2013): 24–46. http://dx.doi.org/10.3167/trans.2013.030203.
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This article deals with the history of underwater film and the role that increased mobility plays in the exploration of nature. Drawing on research on the exploration of the ocean, it analyzes the production of popular images of the sea. The entry of humans into the depths of the oceans in the twentieth century did not revitalize myths of mermaids but rather retold oceanic myths in a modern fashion. Three stages stand out in this evolution of diving mobility. In the 1920s and 1930s, scenes of divers walking under water were the dominant motif. From the 1940s to the 1960s, use of autonomous diving equipment led to a modern incarnation of the “mermen“ myth. From the 1950s to the 1970s, cinematic technology was able to create visions of entire oceanic ecosystems. Underwater films contributed to the period of machine-age exploration in a very particular way: they made virtual voyages of the ocean possible and thus helped to shape the current understanding of the oceans as part of Planet Earth.
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Allard, Maxime. "Passeurs de frontières (du) théologico-politique(s)." Sociologie et sociétés 42, no. 1 (June 15, 2010): 19–44. http://dx.doi.org/10.7202/039997ar.
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RésuméLe début de la modernité est marqué par l’érection de nouvelles frontières théologico-politiques et, du coup, par l’émergence d’une nouvelle figure du passeur (le « ministre ») qui en oblitère une plus ancienne (le « médiateur »). La mise en place de ces frontières est l’occasion de la prise en compte de « passions » qui interviennent aussi dans les transformations des figures du passeur. Pour présenter ces divers déplacements, constructions et émergences, l’article met en cause certaines catégories habituelles autour du « théologico-politique », configure heuristiquement des types de passeurs, et propose de déployer autrement ce qui se joue là. Des textes de Hobbes, Hume et Spinoza servent à ancrer historiquement la réflexion ; des catégories de Lyotard, Foucault, d’Agamben et de Margel contribuent à l’établir théoriquement.
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Dorais, Michel, and Simon Louis Lajeunesse. "Intimité à vendre : comment devient-on travailleur du sexe ?" Sociologie et sociétés 35, no. 2 (July 15, 2004): 121–38. http://dx.doi.org/10.7202/008526ar.
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RésuméÀ partir d’une recherche empirique effectuée auprès de40jeunes hommes travailleurs du sexe (prostitués de rue, danseurs nus et escortes), sont dégagés quatre profils ou scénarios de vie chez les répondants : la dérive, dans laquelle toxicomanie et prostitution vont de pair ; l’appoint, qui se manifeste chez des jeunes pour lesquels la prostitution représente un moyen provisoire ou occasionnel d’augmenter leurs revenus ; l’appartenance, que l’on rencontre chez des jeunes pour qui le milieu de la prostitution était déjà ou est devenu leur « famille » ; enfin, la libération, identifiée chez des jeunes pour lesquels les activités prostitutionnelles sont des plus gratifiantes puisqu’elles leur servent à se réaliser comme personne sur divers plans. Nous en concluons que la prostitution des garçons est un phénomène pluriel et que les interventions les concernant (notamment la prévention de la transmission demtset duvih) devraient en tenir compte.
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Szymak, Piotr, Paweł Piskur, and Krzysztof Naus. "The Effectiveness of Using a Pretrained Deep Learning Neural Networks for Object Classification in Underwater Video." Remote Sensing 12, no. 18 (September 16, 2020): 3020. http://dx.doi.org/10.3390/rs12183020.
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Video image processing and object classification using a Deep Learning Neural Network (DLNN) can significantly increase the autonomy of underwater vehicles. This paper describes the results of a project focused on using DLNN for Object Classification in Underwater Video (OCUV) implemented in a Biomimetic Underwater Vehicle (BUV). The BUV is intended to be used to detect underwater mines, explore shipwrecks or observe the process of corrosion of munitions abandoned on the seabed after World War II. Here, the pretrained DLNNs were used for classification of the following type of objects: fishes, underwater vehicles, divers and obstacles. The results of our research enabled us to estimate the effectiveness of using pretrained DLNNs for classification of different objects under the complex Baltic Sea environment. The Genetic Algorithm (GA) was used to establish tuning parameters of the DLNNs. Three different training methods were compared for AlexNet, then one training method was chosen for fifteen networks and the tests were provided with the description of the final results. The DLNNs were trained on servers with six medium class Graphics Processing Units (GPUs). Finally, the trained DLNN was implemented in the Nvidia JetsonTX2 platform installed on board of the BUV, and one of the network was verified in a real environment.
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Sousa, J. J., and L. Bastos. "Multi-temporal SAR interferometry reveals acceleration of bridge sinking before collapse." Natural Hazards and Earth System Sciences 13, no. 3 (March 18, 2013): 659–67. http://dx.doi.org/10.5194/nhess-13-659-2013.
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Abstract. On the night of 4 March 2001, at Entre-os-Rios (Northern Portugal), the Hintze Ribeiro centennial bridge collapsed killing 59 people traveling in a bus and three cars that were crossing the Douro River. According to the national authorities, the collapse was due to two decades of uncontrolled sand extraction which compromised the stability of the bridge's pillars, together with underestimating the warnings from divers and technicians. In this work we do not intend to corroborate or contradict the official version of the accident's causes, but only demonstrate the potential of Multi-Temporal Interferometric techniques for detection and monitoring of deformations in structures such as bridges, and consequently the usefulness of the derived information in some type of early warning system to help prevent new catastrophic events. Based on the analysis of 52 ERS-1/2 covering the period from May 1995 to the fatal occurrence, we were able to detect significant movements, reaching rates of 20 mm yr−1, in the section of the bridge that fell into the Douro River, which are obvious signs of the bridge's instability. These promising results demonstrate that with the new high-resolution synthetic aperture radar satellite scenes it is possible to develop interferometric based methodologies for structural health monitoring.
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Barr, William. "Discovery of the wreck of the Soviet steamer Chelyuskin on the bed of the Chukchi Sea." Polar Record 43, no. 1 (January 2007): 67–70. http://dx.doi.org/10.1017/s0032247406216061.
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In 1933, the steamer Chelyuskin sailed from Murmansk, east bound to attempt a transit of the Northern Sea Route to the Pacific, in order to demonstrate that such a transit could be achieved in one season. The vessel became beset in heavy ice in the Chukchi Sea, and after drifting with the ice for over two months, was crushed and sank on 13 February 1934. Apart from one fatality, her entire complement of 104 people was able to establish a camp on the sea ice. The Soviet government organised an impressive aerial evacuation, under which all were rescued. Following several unsuccessful attempts, the wreck was located on the bed of the Chukchi Sea by a Russian expedition, Chelyuskin-70, in mid-September 2006. Two small components of the ship's superstructure were recovered by divers and were sent to the ship's builders, Burmeister and Wein of Copenhagen, for identification.
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Deshayes, Fabien. "D’amour ou de raison ?" Sociologie et sociétés 48, no. 2 (October 24, 2016): 131–53. http://dx.doi.org/10.7202/1037718ar.
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Cet article narre un mariage mixte dans des familles pauvres, entre une femme française âgée de 60 ans et un homme algérien âgé de 44 ans, qui se sont connus quelques mois avant cette union. Des préparatifs à la cérémonie en passant par les conséquences de cette alliance sur le groupe familial, nous suivons chronologiquement les épreuves administratives que doit traverser le couple ainsi que les jugements des proches sur cet événement. En recueillant la parole des divers protagonistes concernés par ce mariage, ce texte souligne les bouleversements qu’il provoque. Cette union a des effets sur les équilibres antérieurs et modifie sensiblement la place des hébergés qui vivent dans l’appartement du couple ainsi que celle des proches. Ceux qu’il s’agissait d’épauler hier reculent dans la hiérarchie et se voient contraints d’envisager de nouvelles protections. Avec cette union, c’est tout le paysage des liens interpersonnels qui se recompose. L’étude ethnographique du mariage permet de lever le voile sur l’ampleur des liens d’interdépendance qui caractérisent les milieux pauvres, que ce soit par l’intermédiaire de transferts économiques, d’hébergements ou par tout un ensemble de services rendus.
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Welhan, J. A. "Methane and hydrogen in mid-ocean-ridge basalt glasses: analysis by vacuum crushing." Canadian Journal of Earth Sciences 25, no. 1 (January 1, 1988): 38–48. http://dx.doi.org/10.1139/e88-004.
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A comparative study of vacuum crushing methods for analyzing reactive gases in basaltic glasses shows that ball milling is an efficient means of releasing occluded gases but that blank production represents a potentially serious problem that must be accounted for when determining reactive-gas compositions. Production of H2 and CH4 in a stainless-steel ball mill in the absence of rock material increases with length of crushing time. However, test results presented here indicate that blank levels are reduced during the actual crushing process by the presence of rock powder, which may act as a cushion to reduce metal–metal contact. Crushing in copper tubes under a hydraulic press produces no blanks for these gases, but crushing efficiency and gas release are very low, and gas adsorption on rock powder becomes a significant problem. Experiments with methane adsorption on crushed basalt suggest that the loss of methane is a chemisorption process that is, for the most part, irreversible.Applying corrections for these effects, we find that H2/CH4 ratios (~3 – 30) in mid-ocean-ridge basalt glasses are similar to those seen in high-temperature mid-ocean-ridge hydrothermal fluids. These data, arguments based on the similarity of water/rock mass ratios calculated from basalt gas data, and the uniformity of methane/helium ratios in divers high-temperature mid-ocean-ridge hydrothermal fluids support the contention that dissolved CH4 and H2 in these fluids are predominantly derived from leaching of mid-ocean-ridge basalt.
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Étienne, Samuel, and Marie-Françoise André. "La variabilité de la hiérarchie des processus de météorisation à travers les bilans météoriques de divers milieux périglaciaires nord-atlantiques (Islande, Labrador, Laponie, Spitsberg) / Variability in the hierarchy of weathering processes detected through weathering budgets of several North-Atlantic periglacial environments (Iceland, Labrador, Lapland, Spitsbergen)." Géomorphologie : relief, processus, environnement 9, no. 3 (2003): 177–89. http://dx.doi.org/10.3406/morfo.2003.1178.
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AL-Emami, Omar, Gabriela M Medero, Fernando A M Marinho, and Melis Sutman. "Analysis of the suction evolution during direct shear test in a silty sand soil." E3S Web of Conferences 195 (2020): 03031. http://dx.doi.org/10.1051/e3sconf/202019503031.
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Shear strength of soils is one of the essential parameters for analysing and solving divers geotechnical problems (e.g. the bearing capacity of shallow footings pile foundations, slope stability and earth embankments). In this study, a series of conventional large-scale (300 X 300 mm) direct shear tests were carried out on saturated and constant water content silty sand specimens at ei = 0.6 and 1.0 tested under applied vertical stresses of 100, 200, or 400 kPa to investigate the influence of matric suction on the shear strength characteristics of the tested material. A loading steel cap was modified to allow the direct measurements of the matric suction using two commercial available Equitensiometer suction probes (EQ3). The experimental program indicated that, for both studied void ratios, the obtained shear strength of specimens under constant water content is found to be distinctly greater than those obtained from saturated samples. The results showed that the samples compacted at ei = 1.0 exhibited collapse behaviour during saturation stage, whereas same samples did not show any volume change during stabilisation stage when tested under constant water content condition. The study results also showed that the matric suction reduction during consolidation stage depends on initial void ratio of the tested samples as well as the level of applied vertical stress. Moreover, the matric suction evolution during shearing process of both studied void ratios specimens decreased with increasing the level of applied vertical stress.
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Jakobsson, Martin, Matt O'Regan, Carl-Magnus Mörth, Christian Stranne, Elizabeth Weidner, Jim Hansson, Richard Gyllencreutz, et al. "Potential links between Baltic Sea submarine terraces and groundwater seeping." Earth Surface Dynamics 8, no. 1 (January 3, 2020): 1–15. http://dx.doi.org/10.5194/esurf-8-1-2020.
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Abstract. Submarine groundwater discharge (SGD) influences ocean chemistry, circulation, and the spreading of nutrients and pollutants; it also shapes sea floor morphology. In the Baltic Sea, SGD was linked to the development of terraces and semicircular depressions mapped in an area of the southern Stockholm archipelago, Sweden, in the 1990s. We mapped additional parts of the Stockholm archipelago, areas in Blekinge, southern Sweden, and southern Finland using high-resolution multibeam sonars and sub-bottom profilers to investigate if the sea floor morphological features discovered in the 1990s are widespread and to further address the hypothesis linking their formation to SGD. Sediment coring and sea floor photography conducted with a remotely operated vehicle (ROV) and divers add additional information to the geophysical mapping results. We find that terraces, with general bathymetric expressions of about 1 m and lateral extents of sometimes >100 m, are widespread in the surveyed areas of the Baltic Sea and are consistently formed in glacial clay. Semicircular depressions, however, are only found in a limited part of a surveyed area east of the island of Askö, southern Stockholm archipelago. While submarine terraces can be produced by several processes, we interpret our results to be in support of the basic hypothesis of terrace formation initially proposed in the 1990s; i.e. groundwater flows through siltier, more permeable layers in glacial clay to discharge at the sea floor, leading to the formation of a sharp terrace when the clay layers above seepage zones are undermined enough to collapse. By linking the terraces to a specific geologic setting, our study further refines the formation hypothesis and thereby forms the foundation for a future assessment of SGD in the Baltic Sea that may use marine geological mapping as a starting point. We propose that SGD through the submarine sea floor terraces is plausible and could be intermittent and linked to periods of higher groundwater levels, implying that to quantify the contribution of freshwater to the Baltic Sea through this potential mechanism, more complex hydrogeological studies are required.
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Furlani, Stefano, Valeria Vaccher, Vanja Macovaz, and Stefano Devoto. "A Cost-Effective Method to Reproduce the Morphology of the Nearshore and Intertidal Zone in Microtidal Environments." Remote Sensing 12, no. 11 (June 10, 2020): 1880. http://dx.doi.org/10.3390/rs12111880.
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The photogrammetric method is widely used in coastal areas and in submerged environments. Time-lapse images collected with unmanned aerial vehicles are used to reproduce the emerged areas, while images taken by divers are used to reproduce submerged ones. Conversely, 3D models of natural or human-made objects lying at the water level are severely affected by the difference in refractive index between air and seawater. For this reason, the matching of 3D models of emergent and submerged coasts has been very rarely tested and never used in Earth Sciences. The availability of a large number of time-lapse images, collected at the intertidal zone during previous snorkel surveys, encouraged us to test the merging of 3D models of emerged and submerged environments. Considering the rapid and effective nature of the aforementioned program of swim surveys, photogrammetric targets were not used during image acquisition. This forced us to test the matching of the independent models by recognizing prominent landforms along the waterline. Here we present the approach used to test the method, the instrumentation used for the field tests, and the setting of cameras fixed to a specially built aluminum support console and discuss both its advantages and its limits compared to UAVs. 3D models of sea cliffs were generated by applying structure-from-motion (SfM) photogrammetry. Horizontal time-lapse images, collected with action cameras while swimming parallel to the coastline at nearly constant velocity, were used for the tests. Subsequently, prominent coastal landforms were used to couple the independent models obtained from the emergent and submerged cliffs. The method was pilot tested in two coastal sites in the north-eastern Adriatic (part of the Mediterranean basin). The first site was a 25 m sea wall of sandstone set within a small harbor, while the second site was a 150 m route below plunging limestone cliffs. The data show that inexpensive action cameras provide a sufficient resolution to support and integrate geomorphological field surveys along rocky coastlines.
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Morris, David J., John K. Pinnegar, David L. Maxwell, Stephen R. Dye, Liam J. Fernand, Stephen Flatman, Oliver J. Williams, and Stuart I. Rogers. "Over 10 million seawater temperature records for the United Kingdom Continental Shelf between 1880 and 2014 from 17 Cefas (United Kingdom government) marine data systems." Earth System Science Data 10, no. 1 (January 9, 2018): 27–51. http://dx.doi.org/10.5194/essd-10-27-2018.
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Abstract. The datasets described here bring together quality-controlled seawater temperature measurements from over 130 years of departmental government-funded marine science investigations in the UK (United Kingdom). Since before the foundation of a Marine Biological Association fisheries laboratory in 1902 and through subsequent evolutions as the Directorate of Fisheries Research and the current Centre for Environment Fisheries & Aquaculture Science, UK government marine scientists and observers have been collecting seawater temperature data as part of oceanographic, chemical, biological, radiological, and other policy-driven research and observation programmes in UK waters. These datasets start with a few tens of records per year, rise to hundreds from the early 1900s, thousands by 1959, and hundreds of thousands by the 1980s, peaking with > 1 million for some years from 2000 onwards. The data source systems vary from time series at coastal monitoring stations or offshore platforms (buoys), through repeated research cruises or opportunistic sampling from ferry routes, to temperature extracts from CTD (conductivity, temperature, depth) profiles, oceanographic, fishery and plankton tows, and data collected from recreational scuba divers or electronic devices attached to marine animals. The datasets described have not been included in previous seawater temperature collation exercises (e.g. International Comprehensive Ocean–Atmosphere Data Set, Met Office Hadley Centre sea surface temperature data set, the centennial in situ observation-based estimates of sea surface temperatures), although some summary data reside in the British Oceanographic Data Centre (BODC) archive, the Marine Environment Monitoring and Assessment National (MERMAN) database and the International Council for the Exploration of the Sea (ICES) data centre. We envisage the data primarily providing a biologically and ecosystem-relevant context for regional assessments of changing hydrological conditions around the British Isles, although cross-matching with satellite-derived data for surface temperatures at specific times and in specific areas is another area in which the data could be of value (see e.g. Smit et al., 2013). Maps are provided indicating geographical coverage, which is generally within and around the UK Continental Shelf area, but occasionally extends north from Labrador and Greenland to east of Svalbard and southward to the Bay of Biscay. Example potential uses of the data are described using plots of data in four selected groups of four ICES rectangles covering areas of particular fisheries interest. The full dataset enables extensive data synthesis, for example in the southern North Sea where issues of spatial and numerical bias from a data source are explored. The full dataset also facilitates the construction of long-term temperature time series and an examination of changes in the phenology (seasonal timing) of ecosystem processes. This is done for a wide geographic area with an exploration of the limitations of data coverage over long periods. Throughout, we highlight and explore potential issues around the simple combination of data from the diverse and disparate sources collated here. The datasets are available on the Cefas Data Hub (https://www.cefas.co.uk/cefas-data-hub/). The referenced data sources are listed in Sect. 5.
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MacDonald, Mariah G., Rebekah I. Dawson, Sarah J. Morrison, Eve J. Lee, and Arjun Khandelwal. "Forming Diverse Super-Earth Systems In Situ." Astrophysical Journal 891, no. 1 (February 28, 2020): 20. http://dx.doi.org/10.3847/1538-4357/ab6f04.
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Kohler, F., T. G. Holland, J. S. Kotiaho, M. Desrousseaux, and M. D. Potts. "Embracing diverse worldviews to share planet Earth." Conservation Biology 33, no. 5 (April 25, 2019): 1014–22. http://dx.doi.org/10.1111/cobi.13304.
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Davoult, Nicole. "Fiscalité de crise ou crise de la fiscalité internationale ?" Gestion & Finances Publiques, no. 4 (July 2021): 43–50. http://dx.doi.org/10.3166/gfp.2021.4.007.
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Les règles fiscales internationales ont été adaptées à la pandémie dans l’urgence sans créer a priori de contraintes, afin de garantir la sécurité juridique. Les analyses de l’OCDE, ainsi que celles de l’administration et la jurisprudence, portent sur la localisation des contribuables, fondée sur le concept de résidence dont la portée serait peu modifiée pour les personnes physiques, contrairement aux entreprises, et sur la répartition du pouvoir d’imposer à travers l’établissement stable et les prix de transfert qui seraient plus fortement impactés. Le système international de répartition fait parallèlement l’objet d’une réforme par l’OCDE en 2020, initialement en réponse aux enjeux de la numérisation de l’économie. Le Pilier Un porte sur la répartition des droits d’imposition entre les pays et vise notamment à l’orienter davantage au profit des juridictions de marché, pour les activités reposant à des degrés divers sur des services numériques, avec un nouveau lien de nature économique (« nexus »). Le Pilier Deux prévoit que les sociétés multinationales paient un impôt minimum sur leurs bénéfices si leur taux effectif d’imposition est inférieur à ce plancher. Avec le soutien des États-Unis, cette proposition dont l’incidence budgétaire est limitée pourra être adoptée dans le contexte d’une crise qui renforce les demandes de solidarité internationale.
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Papakonstantinou, Apostolos, Chrysa Stamati, and Konstantinos Topouzelis. "Comparison of True-Color and Multispectral Unmanned Aerial Systems Imagery for Marine Habitat Mapping Using Object-Based Image Analysis." Remote Sensing 12, no. 3 (February 7, 2020): 554. http://dx.doi.org/10.3390/rs12030554.
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The use of unmanned aerial systems (UAS) over the past years has exploded due to their agility and ability to image an area with high-end products. UAS are a low-cost method for close remote sensing, giving scientists high-resolution data with limited deployment time, accessing even the most inaccessible areas. This study aims to produce marine habitat mapping by comparing the results produced from true-color RGB (tc-RGB) and multispectral high-resolution orthomosaics derived from UAS geodata using object-based image analysis (OBIA). The aerial data was acquired using two different types of sensors—one true-color RGB and one multispectral—both attached to a UAS, capturing images simultaneously. Additionally, divers’ underwater images and echo sounder measurements were collected as in situ data. The produced orthomosaics were processed using three scenarios by applying different classifiers for the marine habitat classification. In the first and second scenario, the k-nearest neighbor (k-NN) and fuzzy rules were applied as classifiers, respectively. In the third scenario, fuzzy rules were applied in the echo sounder data to create samples for the classification process, and then the k-NN algorithm was used as the classifier. The in situ data collected were used as reference and training data. Additionally, these data were used for the calculation of the overall accuracy of the OBIA process in all scenarios. The classification results of the three scenarios were compared. Using tc-RGB instead of multispectral data provides better accuracy in detecting and classifying marine habitats when applying the k-NN as the classifier. In this case, the overall accuracy was 79%, and the Kappa index of agreement (KIA) was equal to 0.71, which illustrates the effectiveness of the proposed approach. The results showed that sub-decimeter resolution UAS data revealed the sub-bottom complexity to a large extent in relatively shallow areas as they provide accurate information that permits the habitat mapping in extreme detail. The produced habitat datasets are ideal as reference data for studying complex coastal environments using satellite imagery.
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Corrêa, Diogo Silva, and André Ricardo do P. Magnelli. "L’apocalypse de Gaïa : la cosmopolitique pour l’Anthropocène de Bruno Latour." Natures Sciences Sociétés 28, no. 3-4 (July 2020): 314–22. http://dx.doi.org/10.1051/nss/2021013.
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Nous vivons dans une société qui, tel unTitanicà la rencontre de son iceberg, persiste à accélérer vers une catastrophe incontrôlable. Les différents signes de la « grande accélération » de l’ère de l’Anthropocène s’accumulent sans cesse. Aurions-nous enfin acquis, avec la pandémie, une (nouvelle) sensibilité aux avertissements constants qui, souvent par lanceurs d’alerte, résonnent avec l’émergence du « nouveau régime climatique » ? Face à la folie de notre temps, c’est d’abord de la perplexité qu’affiche l’anthropologue et philosophe Bruno Latour. On propose de réfléchir ici aux défis actuels en dialogue avec la pensée de Latour sur la mutation écologique, notamment avec ses arguments présents dans deux de ses ouvrages,Face à GaïaetOù atterrir ?. Nous présentons son diagnostic du temps et ses propositions scientifiques, esthétiques et politiques, en montrant comment il entrelace les fils les plus divers de savoirs − science, politique, religion, esthétique, guerre – pour recomposer le monde et rendre la paix possible.
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Jhan, Jyun-Ping, Jiann-Yeou Rau, and Chih-Ming Chou. "Underwater 3D Rigid Object Tracking and 6-DOF Estimation: A Case Study of Giant Steel Pipe Scale Model Underwater Installation." Remote Sensing 12, no. 16 (August 12, 2020): 2600. http://dx.doi.org/10.3390/rs12162600.
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The Zengwen desilting tunnel project installed an Elephant Trunk Steel Pipe (ETSP) at the bottom of the reservoir that is designed to connect the new bypass tunnel and reach downward to the sediment surface. Since ETSP is huge and its underwater installation is an unprecedented construction method, there are several uncertainties in its dynamic motion changes during installation. To assure construction safety, a 1:20 ETSP scale model was built to simulate the underwater installation procedure, and its six-degrees-of-freedom (6-DOF) motion parameters were monitored by offline underwater 3D rigid object tracking and photogrammetry. Three cameras were used to form a multicamera system, and several auxiliary devices—such as waterproof housing, tripods, and a waterproof LED—were adopted to protect the cameras and to obtain clear images in the underwater environment. However, since it is difficult for the divers to position the camera and ensure the camera field of view overlap, each camera can only observe the head, middle, and tail parts of ETSP, respectively, leading to a small overlap area among all images. Therefore, it is not possible to perform a traditional method via multiple images forward intersection, where the camera’s positions and orientations have to be calibrated and fixed in advance. Instead, by tracking the 3D coordinates of ETSP and obtaining the camera orientation information via space resection, we propose a multicamera coordinate transformation and adopted a single-camera relative orientation transformation to calculate the 6-DOF motion parameters. The offline procedure is to first acquire the 3D coordinates of ETSP by taking multiposition images with a precalibrated camera in the air and then use the 3D coordinates as control points to perform the space resection of the calibrated underwater cameras. Finally, we calculated the 6-DOF of ETSP by using the camera orientation information through both multi- and single-camera approaches. In this study, we show the results of camera calibration in the air and underwater environment, present the 6-DOF motion parameters of ETSP underwater installation and the reconstructed 4D animation, and compare the differences between the multi- and single-camera approaches.
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Wallace, Laura M. "Slow Slip Events in New Zealand." Annual Review of Earth and Planetary Sciences 48, no. 1 (May 30, 2020): 175–203. http://dx.doi.org/10.1146/annurev-earth-071719-055104.
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Continuously operating global positioning system sites in the North Island of New Zealand have revealed a diverse range of slow motion earthquakes on the Hikurangi subduction zone. These slow slip events (SSEs) exhibit diverse characteristics, from shallow (<15 km), short (<1 month), frequent (every 1–2 years) events in the northern part of the subduction zone to deep (>30 km), long (>1 year), less frequent (approximately every 5 years) SSEs in the southern part of the subduction zone. Hikurangi SSEs show intriguing relationships to interseismic coupling, seismicity, and tectonic tremor, and they exhibit a diversity of interactions with large, regional earthquakes. Due to the marked along-strike variations in Hikurangi SSE characteristics, which coincide with changes in physical characteristics of the subduction margin, the Hikurangi subduction zone presents a globally unique natural laboratory to resolve outstanding questions regarding the origin of episodic, slow fault slip behavior. ▪ New Zealand's Hikurangi subduction zone hosts slow slip events with a diverse range of depth, size, duration, and recurrence characteristics. ▪ Hikurangi slow slip events show intriguing relationships with seismicity ranging from small earthquakes and tremor to larger earthquakes. ▪ Slow slip events play a major role in the accommodation of plate motion at the Hikurangi subduction zone. ▪ Many aspects of the Hikurangi subduction zone make it an ideal natural laboratory to resolve the physical processes controlling slow slip.
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Vellino, André. "Harmonizing the Metadata Among Diverse Climate Change Datasets." International Journal of Digital Curation 10, no. 1 (May 14, 2015): 268–79. http://dx.doi.org/10.2218/ijdc.v10i1.367.
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One of the critical problems in the curation of research data is the harmonization of its internal metadata schemata. The value of harmonizing such data is well illustrated by the Berkeley Earth project, which successfully integrated into one metadata schema the raw climate datasets from a wide variety geographical sources and time periods (250 years). Doing this enabled climate scientists to calculate a more accurate estimate of the recent changes in Earth’s average land surface temperatures and to ascertain the extent to which climate change is anthropogenic. This paper surveys some of the approaches that have been taken to the integration of data schemata in general and examines some of the specific metadata features of the source surface temperature datasets that were harmonized by Berkeley Earth. The conclusion drawn from this analysis is that the original source data and the Berkeley Earth common format provides a promising training set on which to apply machine learning methods for replicating the human data integration process. This paper describes research in progress on a domain-independent approach to the metadata harmonization problem that could be applied to other fields of study and be incorporated into a data portal to enhance the discoverability and reuse of data from a broad range of data sources.
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Bergström, B. I., G. Hempel, H. P. Marschall, A. North, V. Siegel, and J. O. Strömberg. "Spring distribution, size composition and behaviour of krill Euphausia superba in the western Weddell Sea." Polar Record 26, no. 157 (April 1990): 85–89. http://dx.doi.org/10.1017/s0032247400011128.
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AbstractDistribution, size composition and behaviour of Euphausia superba were investigated in the northwestern Weddell Sea (59–63°S, 45–52°W) in October-November 1988 using RMT trawling, SCUBA diving and visual examination of the ice undersurface using a remotely-operated vehicle (ROV). Amounts of krill washed onto the ice during ice-breaking along transects were noted. Juvenile and sub-adult krill were found, often in high numbers, in association with seasonal pack-ice, from the outer marginal ice zone to at least 200 nautical miles [3 50 km] into the closed pack-ice zone. Krill caught with the RMT or observed within or close to the ice usually had full guts. They were frequently seen feeding on ice algae, and seemed to concentrate in pressure zones, melting ice and infiltration layers, ie where ice provided both confining crevices and rich algal growth. During twilight numbers of krill increased in open water close to the ice, though ROV observations at night revealed even greater numbers remaining in ice cavities. Direct observations from deck, by divers and by ROV, confirmed that most of the krill population in the uppermost water layer was confined to ice habitats, though in three out of 20 RMT catches krill reached densities of 0.1 nr3 ie normal summer values. ‘Miniswarms’ forming in early November may indicate seasonal transition of at least part of the krill population from winter ice habitat and grazing on ice-algae, to summer pelagic life and filter-feeding on phytoplankton.
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Croft, Darin A., Javier N. Gelfo, and Guillermo M. López. "Splendid Innovation: The Extinct South American Native Ungulates." Annual Review of Earth and Planetary Sciences 48, no. 1 (May 30, 2020): 259–90. http://dx.doi.org/10.1146/annurev-earth-072619-060126.
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A remarkable diversity of plant-eating mammals known as South American native ungulates (SANUs) flourished in South America for most of the Cenozoic. Although some of these species likely filled ecological niches similar to those of modern hoofed mammals, others differed substantially from extant artiodactyls and perissodactyls in their skull and limb anatomy and probably also in their ecology. Notoungulates and litopterns were the longest-lived and most diverse SANU clades and survived into the Quaternary; astrapotheres went extinct in the late Miocene, whereas other SANU groups were restricted to the Paleogene. Neogene notoungulates were quite specialized in craniodental structure, but many were rather unspecialized postcranially; in contrast, litopterns evolved limb specializations early in their history while maintaining more conservative dentitions. In this article, we review the current understanding of SANU evolutionary relationships and paleoecology, provide an updated compilation of genus temporal ranges, and discuss possible directions for future research. ▪ South American native ungulates (SANUs) were a diverse, long-lived, and independent radiation of mammals into varied terrestrial plant-eater niches. ▪ We review origins, evolution, and paleoecology of the major SANU clades: Notoungulata, Litopterna, Astrapotheria, Xenungulata, and Pyrotheria. ▪ At their peak, during the Eocene and Oligocene, more than 40 genera of native ungulates inhabited South America at any one time. ▪ SANUs ranged from <1 kg to several tons and evolved many combinations of diet and locomotor adaptations not seen in living ungulates.
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Fagundes, Henrique Delevati, Rafael Gomes Dionello, Lauri Lourenço Radünz, and Francisco Wilson Reichert Júnior. "CONTROL OF MAIZE WEEVIL WITH APPLICATION OF DIATOMACEOUS EARTH IN CORN GRAINS STORED IN DIVERSE TEMPERATURES." REVISTA ENGENHARIA NA AGRICULTURA - REVENG 27, no. 5 (August 28, 2019): 400–411. http://dx.doi.org/10.13083/reveng.v27i5.948.
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The insect known as maize weevil (Sitophilus zeamais) is one of the most important pests of stored corn in Brazil. Among the various forms of control, one can highlight the use of inert powders, which has advantages of not providing risk to the environment or to human and animal health, besides not having reports of insect resistance. Thus, this work evaluated the effect of different doses of diatomaceous earth on the development of Sitophilus zeamais on two temperature conditions on corn grain storage. A completely randomized design was adopted in a factorial 4x2x4 (diatomaceous earth dose x storage temperature x storage time) dosage, with three replicates. The diatomaceous earth doses were: 0, 250, 500 and 1000 g t-1 and subsequently stored at temperatures of 22 and 30°C for 90 days. The bulk density decreased during the storage for all diatomaceous earth doses applied, but in inverse proportion to the dose increment. Diatomaceous earth has proven better efficiency in the control of S. zeamais, with increase in dose and storage temperature. Dry weight decrease was observed in all doses and storage temperatures evaluated, but it was more pronounced in those grains that have not received the application of diatomaceous earth.
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Zhan, Zhongwen. "Mechanisms and Implications of Deep Earthquakes." Annual Review of Earth and Planetary Sciences 48, no. 1 (May 30, 2020): 147–74. http://dx.doi.org/10.1146/annurev-earth-053018-060314.
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Deep earthquakes behave like shallow earthquakes but must have fundamentally different physical processes. Their rupture behaviors, magnitude-frequency statistics, and aftershocks are diverse and imperfectly dependent on various factors, such as slab temperature, depth, and magnitude. The three leading mechanisms for deep earthquakes (i.e., transformational faulting, dehydration embrittlement, and thermal runaway) can each explain portions of the observations but have potentially fundamental difficulties explaining the rest. This situation calls for more serious consideration of hypotheses that involve more than one mechanism. For example, deep earthquakes may initiate by one mechanism, but the ruptures may propagate via another mechanism once triggered. To make further progress, it is critical to evaluate the hypotheses, both single- or dual-mechanism, under conditions as close to those of real slabs as possible to make accurate and specific predictions that are testable using seismic or other geophysical observations. Any new understanding of deep earthquakes promises new constraints on subduction zone structure and dynamics. ▪ Deep earthquakes display the complex structure and dynamics of subduction zones in terms of geometry, stress state, rheology, hydration, and phase changes. ▪ Phase transformation, dehydration, and thermal runaway are the leading mechanisms for deep earthquakes, but all have major gaps or fundamental difficulties. ▪ Deep earthquakes may involve dual-mechanism processes, as hinted at by the diverse rupture and statistic properties and the break of self-similarity. ▪ Further progresses would benefit from specific and testable predictions that consider realistic slab conditions with insights from geodynamics, petrology, and mineral physics.
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Keller, Klaus, Casey Helgeson, and Vivek Srikrishnan. "Climate Risk Management." Annual Review of Earth and Planetary Sciences 49, no. 1 (May 30, 2021): 95–116. http://dx.doi.org/10.1146/annurev-earth-080320-055847.
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Accelerating global climate change drives new climate risks. People around the world are researching, designing, and implementing strategies to manage these risks. Identifying and implementing sound climate risk management strategies poses nontrivial challenges including ( a) linking the required disciplines, ( b) identifying relevant values and objectives, ( c) identifying and quantifying important uncertainties, ( d) resolving interactions between decision levers and the system dynamics, ( e) quantifying the trade-offs between diverse values under deep and dynamic uncertainties, ( f) communicating to inform decisions, and ( g) learning from the decision-making needs to inform research design. Here we review these challenges and avenues to overcome them. ▪ People and institutions are confronted with emerging and dynamic climate risks. ▪ Stakeholder values are central to defining the decision problem. ▪ Mission-oriented basic research helps to improve the design of climate risk management strategies.
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Shellnutt, J. Gregory. "Igneous Rock Associations 21. The Early Permian Panjal Traps of the Western Himalaya." Geoscience Canada 43, no. 4 (December 15, 2016): 251. http://dx.doi.org/10.12789/geocanj.2016.43.104.
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The Early Permian (290 Ma) Panjal Traps are the largest contiguous outcropping of volcanic rocks associated with the Himalayan Magmatic Province (HMP). The eruptions of HMP-related lava were contemporaneous with the initial break-up of Pangea. The Panjal Traps are primarily basalt but volumetrically minor intermediate and felsic volcanic rocks also occur. The basaltic rocks range in composition from continental tholeiite to ocean-floor basalt and nearly all have experienced, to varying extent, crustal contamination. Uncontaminated basaltic rocks have Sr–Nd isotopes similar to a chondritic source (ISr = 0.7043 to 0.7073; eNd(t) = 0 ± 1), whereas the remaining basaltic rocks have a wide range of Nd (eNd(t) = –6.1 to +4.3) and Sr (ISr = 0.7051 to 0.7185) isotopic values. The calculated primary melt compositions of basalt are picritic and their mantle potential temperatures (TP ≤ 1450°C) are similar to ambient mantle rather than anomalously hot mantle. The silicic volcanic rocks were likely derived by partial melting of the crust whereas the andesitic rocks were derived by mixing between crustal and mantle melts. The Traps erupted within a continental rift setting that developed into a shallow sea. Sustained rifting created a nascent ocean basin that led to sea-floor spreading and the rifting of microcontinents from Gondwana to form the ribbon-like continent Cimmeria and the Neotethys Ocean.RÉSUMÉLes Panjal Traps du début Permien (290 Ma) constituent le plus grand affleurement contigu de roches volcaniques associées à la province magmatique de himalayienne (HMP). Les éruptions de lave de type HMP étaient contemporaines de la rupture initiale de la Pangée. Les Panjal Traps sont essentiellement des basaltes, mais on y trouve aussi des roches volcaniques intermédiaires et felsiques en quantités mineures. La composition de ces roches basaltiques varie de tholéiite continentale à basalte de plancher océanique, et presque toutes ont subi, à des degrés divers, une contamination de matériaux crustaux. Les roches basaltiques non contaminées ont des contenus isotopiques Sr–Nd similaires à une source chondritique (Isr = 0,7043 à 0,7073; eNd (t) = 0 ± 1), alors que les roches basaltiques autres montrent une large gamme de valeurs isotopiques en Nd (eNd (t) = –6,1 à +4,3) et Sr (Isr = de 0,7051 à 0,7185). Les compositions de fusion primaire calculées des basaltes sont picritiques et leurs températures potentielles mantelliques (TP de ≤ 1450°C) sont similaires à la température ambiante du manteau plutôt que celle d’un manteau anormalement chaud. Les roches volcaniques siliciques dérivent probablement de la fusion partielle de la croûte alors que les roches andésitiques proviennent du mélange entre des matériaux de fusion crustaux et mantelliques. Les Traps ont fait irruption dans un contexte de rift continental qui s’est développé dans une mer peu profonde. Un rifting soutenu a créé un début de bassin océanique lequel conduit à une expansion du fond océanique et au rifting de microcontinents tirés du Gondwana pour former le continent rubané de Cimméria et l'océan Néotéthys.
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Pyung Rae Lee. "A Study on Earth-diver Myth of Mongolian Ethnic Group." Korean Journal of Folk Studies ll, no. 34 (June 2014): 5–27. http://dx.doi.org/10.35638/kjfs..34.201406.001.
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Berta, Annalisa, Morgan Churchill, and Robert W. Boessenecker. "The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses." Annual Review of Earth and Planetary Sciences 46, no. 1 (May 30, 2018): 203–28. http://dx.doi.org/10.1146/annurev-earth-082517-010009.
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The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.
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Casey, Kerry C., Alexander M. Brown, and Jerome R. Robinson. "Yttrium and lanthanum bis(phosphine-oxide)methanides: structurally diverse, dynamic, and reactive." Inorganic Chemistry Frontiers 8, no. 6 (2021): 1539–52. http://dx.doi.org/10.1039/d0qi01438a.
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Homoleptic yttrium and lanthanum complexes of bis(phosphineoxide) methanides, RE(HPhL)3 and RE2(HMeL)6, promote the first rare-earth mediated Horner-Wittig and acid-base chemistry consistent with multifunctional reactivity (Lewis-acid/Brønstedbase).
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Ozansoy, Cagil, and Douglas Pinto Sampaio Gomes. "Electrical and physical characterization of earth faults for diverse bush species." Engineering Science and Technology, an International Journal 23, no. 5 (October 2020): 1109–17. http://dx.doi.org/10.1016/j.jestch.2020.03.002.
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Quigley, Mark C., Wendy Saunders, Chris Massey, Russ Van Dissen, Pilar Villamor, Helen Jack, and Nicola Litchfield. "The utility of earth science information in post-earthquake land-use decision-making: the 2010–2011 Canterbury earthquake sequence in Aotearoa New Zealand." Natural Hazards and Earth System Sciences 20, no. 12 (December 11, 2020): 3361–85. http://dx.doi.org/10.5194/nhess-20-3361-2020.
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Abstract. Earth science information (data, knowledge, advice) can enhance the evidence base for land-use decision-making. The utility of this information depends on factors including the context and objectives of land-use decisions, the timeliness and efficiency with which earth science information is delivered, and the strength, relevance, uncertainties, and risks assigned to earth science information relative to other inputs. We investigate land-use decision-making practices in Christchurch, New Zealand, and the surrounding region in response to mass movement (e.g., rockfall, cliff collapses) and ground-surface fault rupture hazards incurred during the 2010–2011 Canterbury earthquake sequence (CES). Rockfall fatality risk models combining hazard, exposure, and vulnerability data were co-produced by earth scientists and decision makers and formed primary evidence for risk-based land-use decision-making with adaptive capacity. A public consultation and submission process enabled consideration of additional earth science information primarily via stakeholder requests. For fault rupture hazards, pre-disaster geotechnical guidelines and collaboration networks enhanced the ability of earth scientists to rapidly acquire relevant observational data to meet the demands of decision makers. Expeditious decision-making granted permissive consent for rebuilding in the fault rupture zone based on preliminary scientific advice that was subsequently supported by more comprehensive geological investigations. Rapidly fluctuating and diverse demands for post-disaster earth science information may be best met through the prior establishment of (i) land-use policies and technical guidelines tailored for a variety of diverse disaster scenarios, (ii) hazard and risk analyses in land-use plans, including acquisition of geospatial and other earth science data, and (iii) coordinated scientific networks that may comprise subgroups with diverse goals, operational perspectives, and protocols which allow the many facets of scientific information acquisition and delivery to be successfully addressed. Despite the collective knowledge shared here, some recent land-use practices in New Zealand continue to prioritize other (e.g., socioeconomic) factors above earth science information, even in areas of extreme disaster risk.
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Uchida, Naoki, and Roland Bürgmann. "Repeating Earthquakes." Annual Review of Earth and Planetary Sciences 47, no. 1 (May 30, 2019): 305–32. http://dx.doi.org/10.1146/annurev-earth-053018-060119.
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Repeating earthquakes, or repeaters, are identical in location and geometry but occur at different times. They appear to represent recurring seismic energy release from distinct structures such as slip on a fault patch. Repeaters are most commonly found on creeping plate boundary faults, where seismic patches are loaded by surrounding slow slip, and they can be used to track fault creep at depth. Their hosting environments also include volcanoes, subducted slabs, mining-induced fault structures, glaciers, and landslides. While true repeaters should have identical seismic waveforms, small differences in their seismograms can be used to examine subtle changes in source properties or in material properties of the rocks through which the waves propagate. Source studies have documented the presence of smaller slip patches within the rupture areas of larger repeaters, illuminated earthquake triggering mechanisms, and revealed systematic changes in rupture characteristics as a function of loading rate. ▪ Repeating earthquakes are observed in diverse tectonic and nontectonic settings. ▪ Their occurrence patterns provide quantitative information about fault creep, earthquake cycle dynamics, triggering, and predictability. ▪ Their seismic waveform characteristics provide important insights on earthquake source variability and temporal Earth structure changes.
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Prevec, Stephen A. "Igneous Rock Associations 23. The Bushveld Complex, South Africa: New Insights and Paradigms." Geoscience Canada 45, no. 3-4 (January 28, 2019): 117–35. http://dx.doi.org/10.12789/geocanj.2018.45.138.
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SUMMARYThe Bushveld Complex has continued to serve as the basis for study into the fundamental nature of petrological processes for layered intrusion formation and for oxide and sulphide hosted Platinum Group Element (PGE)–Cu–Ni ore deposits. These studies have included discoveries in terms of the physical extent of Bushveld magmatism, both laterally and internally. Lateral variations in the mafic to ultramafic Rustenburg Layered Suite of the Northern Lobe of the complex have also revealed petrologically distinctive Upper Critical Zone equivalent rocks (the so-called Flatreef) with enhanced contamination and mineralization traits that reflect a transition between Eastern and Western Lobe equivalent stratigraphy and Platreef-style complexity. Traditional magma mixing models have been re-examined in light of radiogenic isotopic evidence for crustal involvement early in the chromite precipitation or formation process, combined with evidence for associated heterogeneous fluid contents, cryptic layering profiles, and textural evidence. A wide variety of alternative ore-genesis models have been proposed as a consequence. The fundamental mechanics of magma chamber processes and the existence of the magma chamber as an entity have been called into question through various lines of evidence which have promoted the concept of progressive emplacement of the complex as a stack of not-necessarily-quite-sequentially intruded sills (with or without significant quantities of transported phenocrysts), emplaced into variably crystallized and compacted crystal-liquid mush mixtures, modified by compaction-driven late magmatic fluid (silicate and aqueous) activity. Alternatively, petrological and geochemical observations have been used to discount these interpretations in favour of more conventional cooling and gravity-driven accumulation of silicate and ore minerals in a large, liquid-dominated system.RÉSUMÉLe complexe de Bushveld a demeuré à la base d’études sur la nature fondamentale des processus pétrologiques de formation d’intrusions litées et des gîtes des éléments du groupe platine (ÉGP)-Cu-Ni hébergés dans les oxydes et les sulfures. Ces études ont comporté des découvertes sur l’étendue physique, à la fois latérale et interne, du magmatisme de Bushveld. Les variations latérales de la suite stratifiée et mafique à ultramafique Rustenburg du lobe nord du complexe ont également révélé des roches équivalentes pétrologiquement distinctes de la zone critique supérieure (le communément désigné Flatreef) avec des traits de contamination et de minéralisation accrus qui reflètent une transition entre la stratigraphie équivalente des lobes est et ouest et la complexité de type Platreef. Les modèles traditionnels de mélanges magmatiques ont été réexaminés à la lumière de preuves isotopiques radiogéniques indiquant une implication de la croûte au début du processus de précipitation ou de formation de la chromite, combinées à des preuves de contenu fluide hétérogène associé, de profils de litage cryptique et de preuves texturales. Ainsi, une grande variété de modèles alternatifs de genèse de minerai a été proposée. La mécanique fondamentale des processus de la chambre magmatique et l'existence de la chambre magmatique en tant qu'entité ont été remises en question au moyen de divers éléments de preuve qui ont mis en avant le concept de mise en place progressive du complexe sous forme d'un empilement non-nécessairement séquentiel de sills injectés (avec ou sans quantités significatives de phénocristaux transportés) mis en place dans des mélanges de bouillie cristaux/liquide à cristallisation et compaction variable, modifiés par une activité tardive de fluide magmatique (silicaté et aqueux) induite par la compaction. Alternativement, des observations pétrologiques et géochimiques ont été utilisées pour écarter ces interprétations en faveur d'un processus plus conventionnel de refroidissement et d’accumulation de minérais silicatés et minéralisés induite par la gravité dans un vaste système à dominance liquide.
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Jontof-Hutter, Daniel. "The Compositional Diversity of Low-Mass Exoplanets." Annual Review of Earth and Planetary Sciences 47, no. 1 (May 30, 2019): 141–71. http://dx.doi.org/10.1146/annurev-earth-053018-060352.
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Low-mass planets have an extraordinarily diverse range of bulk compositions, from primarily rocky worlds to those with deep gaseous atmospheres. As techniques for measuring the masses of exoplanets advance the field toward the regime of rocky planets, from ultrashort orbital periods to Venus-like distances, we identify the bounds on planet compositions, where sizes and incident fluxes inform bulk planet properties. In some cases, the precision of measurement of planet masses and sizes is approaching the theoretical uncertainties in planet models. An emerging picture explains aspects of the diversity of low-mass planets, although some problems remain: Do extreme low-density, low-mass planets challenge models of atmospheric mass loss? Are planet sizes strictly separated by bulk composition? Why do some stellar characterizations differ between observational techniques? With the Transiting Exoplanet Survey Satellite ( TESS) mission, low-mass exoplanets around the nearest stars will soon be discovered and characterized with unprecedented precision, permitting more detailed planetary modeling and atmospheric characterization of low-mass exoplanets than ever before. ▪ Following the Kepler mission, studies of exoplanetary compositions have entered the terrestrial regime. ▪ Low-mass planets have an extraordinary range of compositions, from Earth-like mixtures of rock and metal to mostly tenuous gas. ▪ The TESS mission will discover low-mass planets that can be studied in more detail than ever before.