Journal articles: 'Bois fossile'

1

Giraud, Bernadette, and Annie Lejal-Nicol. "Cassinium dongolense n. sp. bois fossile de caesalpiniaceae du nubien du soudan septentrional." Review of Palaeobotany and Palynology 59, no. 1-4 (June 1989): 37–50. http://dx.doi.org/10.1016/0034-6667(89)90004-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Gros, Jean-Pierre. "Nouveau spécimen de bois fossile de l'Oligocène d'Autriche rapporté à l'espèce Metacacioxylon lemoignei Gros 1981 Emend." Nouvelles archives du Muséum d'histoire naturelle de Lyon 26, no. 1 (1988): 19–27. http://dx.doi.org/10.3406/mhnly.1988.1096.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Vaitilingom, Gilles, Zéphirin Mouloungui, Anthony Benoist, François Broust, Tizane Daho, and Bruno Piriou. "Vers une génération plus « verte » de biodiesels." OCL 28 (2021): 2. http://dx.doi.org/10.1051/ocl/2020067.

Full text

Abstract:

Dans le monde, le pétrole assure 96 % des besoins des transports, lesquels mobilisent 65 % du pétrole consommé et participent à hauteur de 20 % aux émissions de CO2. Afin de réduire la consommation de ressources fossiles, une des alternatives est notamment l’utilisation de « biocarburants ». Ces biocarburants sont classés en trois générations successives. Les biocarburants de première génération sont issus des parties alimentaires de plantes de grande culture : le bioéthanol et le biodiesel. Les biocarburants dits « avancés » de seconde génération sont issus de ressources lignocellulosiques (bois, résidus agricoles...) valorisées soit en bioéthanol soit en hydrocarbures de synthèse. Une troisième génération repose sur la culture de micro-algues productrices d’acides gras transformés en biodiesel. Les biodiesels de première génération, tout comme ceux de deuxième et troisième générations, sont sujets à certaines critiques notamment le CAS (changement d’affectation des sols) et la compétition alimentaire/énergétique. L’objectif de ce travail est d’examiner l’intérêt de deux filières prometteuses. Les biodiesels basés sur des cultures dédiées conduisent à des impacts environnementaux plus réduits mais jouent un rôle dans la problématique des CAS. Alors que celles basées sur les résidus n’y entrent pas et montrent des niveaux de réduction des émissions de gaz à effet de serre entre 83 et 90 % contre 60 à 80 % pour un biodiesel classique par rapport à un carburant diesel fossile. Les esters butyliques d’huiles alimentaires usagées et de graisses animales s’affichent comme des biodiesels « plus verts » et représentent une opportunité pour les biocarburants de deuxième génération et pour une oléochimie « plus verte ».

APA, Harvard, Vancouver, ISO, and other styles

4

Lortie, Guy, and Jean-Claude Dionne. "Analyse préliminaire des diatomées de la coupe de Montmagny, côte sud de l’estuaire du Saint-Laurent, Québec." Géographie physique et Quaternaire 44, no. 1 (December 18, 2007): 89–95. http://dx.doi.org/10.7202/032801ar.

Full text

Abstract:

RÉSUMÉ À Montmagny, sur la rive sud du moyen estuaire du Saint-Laurent, une coupe d'une dizaine de mètres de puissance et comprenant cinq unités stratigraphiques a été étudiée du point de vue de sa micro-flore fossile. Une analyse sommaire des diatomées a permis d'évaluer les conditions environnementales de la mise en place des divers dépôts composant la terrasse de 8-10m à cet endroit. À la base, l'unité I (argile pléni-marine glodthwaitienne, datée à environ 10 000 BP) contient une flore marine très pauvre. L'unité Il (limon argileux avec débris organiques et bois datés à environ 7300 BP dans sa partie supérieure) se caractérise par une flore littorale saumâtre incluant des formes planctoniques marines parfois très abondantes (Thalassiosira ssp. surtout), l'unité III (tourbe datée à environ 6500 BP) contraste par une flore acidophile dulcicole à Eunotia ssp. La flore de l'unité IV (limon sableux) diffère par une teneur en valves plus élevée que dans l'unité III et par des éléments dulcicoles d'eau neutre ou légèrement alcaline fréquents, en particulier à la base. La cinquième unité (tourbe datée à environ 4500 BP) contient une flore acidophile d'eau douce. Les diatomées des unités Il et III indiquent un milieu intertidal saumâtre à faible salinité, ayant évolué progressivement lors d'épisodes de transgression. Toutefois, les conditions du milieu (profondeur d'eau et salinité) semblent avoir varié légèrement selon les époques, avec une diminution de la salinité pour l'unité IV. L'étude des diatomées corrobore l'existence de fluctuations du niveau marin relatif dans l'estuaire du Saint-Laurent au cours de l'Holocène.

APA, Harvard, Vancouver, ISO, and other styles

5

Occhietti, Serge, Michel ChartierH, Claude Hillaire-Marcel, Mario Cournoyer, Stephen L. Cumbaa, and Richard Harington. "Paléoenvironnements de la mer de Champlain dans la région de Québec, entre 11 300 et 9750 bp : le site de Saint-Nicolas." Géographie physique et Quaternaire 55, no. 1 (October 2, 2002): 23–46. http://dx.doi.org/10.7202/005660ar.

Full text

Abstract:

Résumé À Saint-Nicolas, dans le détroit de Québec, des sables de courants de marée de la transition Pléistocène-Holocène contiennent une faune marine fossile exceptionnelle : 34 types d'invertébrés en plus des microfossiles, 3 de mammifères, 3 d'oiseaux et 5 de poissons, d'âge au 14 C compris entre 10 060 et 9810 BP (δ 13 C = 0 ‰). Ils sont recouverts par des tidalites qui marquent la phase ultime de la Mer de Champlain, jusque vers 9750 BP. L'ensemble des données lithologiques, géochimiques et paléontologiques évoque une sédimentation dans un archipel situé à l'entrée de la Mer de Champlain, soumis à des marées de l'ordre de 5 à 10 m d'amplitude. Les forts courants de marée montante ont favorisé le maintien tardif d'apports d'eaux salées. L'archipel a protégé les unités de l'érosion pendant le reflux des marées ainsi que de l'érosion fluviatile ultérieure liée au relèvement glacio-isostatique. La diversité faunique est associée à une forte productivité marine, liée au mélange des eaux douces et salées. La chaîne alimentaire allait de mollusques abondants à marée basse à des poissons, au morse, à des phoques et à des oiseaux qui nidifiaient sur les îlots rocheux. Le maintien de ce système sédimentaire et écologique implique une stabilisation du niveau marin relatif attribuée à la remontée eustatique du début de l'Holocène. La comparaison des âges au 14 C de coquilles marines et de bois permet d'évaluer l'effet du carbone inorganique dissous dans la Mer de Champlain. Les âges des coquilles marines (δ 13 C = 0 ‰) sont vieillis d'au moins 350 ans par rapport aux âges de matériel terrestre (δ 13 C=-25 ‰) en position stratigraphique équivalente.

APA, Harvard, Vancouver, ISO, and other styles

6

Gros, Jean Pierre. "Les bois fossiles d’Éthiopie. Inventaire systématique." Geobios 25, no. 1 (January 1992): 3–12. http://dx.doi.org/10.1016/s0016-6995(09)90033-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Gregory J. Retallack. "Ediacaran periglacial sedimentary structures." Journal of Palaeosciences 70, no. (1-2) (September 10, 2021): 5–30. http://dx.doi.org/10.54991/jop.2021.8.

Full text

Abstract:

Ediacaran fossils are sometimes reconstructed as colorful organisms of clear azure seas like tropical lagoons, or as ghostlike forms in deep, dark oceans. Alternatively, they can be envisaged as sessile organisms in frigid soils, to judge from associated Ediacaran periglacial paleosols and tillites. Additional evidence of cool Ediacaran paleoclimate now comes from reinterpretation of two supposed trace fossils: (1) grooves radiating from Ediacaran fossils interpreted as radular feeding traces (“Kimberichnus”) of supposed molluscs (Kimberella), and (2) chains of fossil impressions interpreted as feeding traces (“Epibaion”) of supposed worms or placozoans (Yorgia, Dickinsonia). The grooves are not curved with rounded ends like radular scratches, but with sharp or crudely bifid tips like frost flowers and frost needles extruded from plant debris. Fossil impressions in chains are not sequential feeding stations, but in polygonal arrays, like vagrant lichens and mosses displaced by wind gusts and periglacial frost boils. Thus, neither the taphomorph “Epibaion”, nor the ice crystal pseudomorphs “Kimberichnus” are valid ichnogenera. These newly recognized frost boils, needle ice, frost feathers, frost hair and frost shawls are additions to isotopic and glendonite evidence that the Ediacaran was another period in Earth history when even low paleolatitudes were cool.

APA, Harvard, Vancouver, ISO, and other styles

8

Gros, Jean Pierre. "Historique des taxons de bois fossiles de mimosaceae." Geobios 27, no. 1 (January 1994): 3–21. http://dx.doi.org/10.1016/s0016-6995(06)80208-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Dupéron, Jean. "Les bois fossiles de juglandaceae: Inventaire et révision." Review of Palaeobotany and Palynology 53, no. 3-4 (January 1988): 251–81. http://dx.doi.org/10.1016/0034-6667(88)90035-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Gros, Jean-Pierre. "La dénomination des bois fossiles identifiés à des Chênes." Bulletin mensuel de la Société linnéenne de Lyon 57, no. 8 (1988): 250–60. http://dx.doi.org/10.3406/linly.1988.10843.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Philippe, Marc, André Giret, and Jordan Gregory J. "Bois fossiles tertiaires et quaternaires de Kerguelen (océan Indien austral)." Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 326, no. 12 (June 1998): 901–6. http://dx.doi.org/10.1016/s1251-8050(98)80030-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Scanferla, Agustín, and Krister T. Smith. "Exquisitely Preserved Fossil Snakes of Messel: Insight into the Evolution, Biogeography, Habitat Preferences and Sensory Ecology of Early Boas." Diversity 12, no. 3 (March 13, 2020): 100. http://dx.doi.org/10.3390/d12030100.

Full text

Abstract:

Our knowledge of early evolution of snakes is improving, but all that we can infer about the evolution of modern clades of snakes such as boas (Booidea) is still based on isolated bones. Here, we resolve the phylogenetic relationships of Eoconstrictor fischeri comb. nov. and other booids from the early-middle Eocene of Messel (Germany), the best-known fossil snake assemblage yet discovered. Our combined analyses demonstrate an affinity of Eoconstrictor with Neotropical boas, thus entailing a South America-to-Europe dispersal event. Other booid species from Messel are related to different New World clades, reinforcing the cosmopolitan nature of the Messel booid fauna. Our analyses indicate that Eoconstrictor was a terrestrial, medium- to large-bodied snake that bore labial pit organs in the upper jaw, the earliest evidence that the visual system in snakes incorporated the infrared spectrum. Evaluation of the known palaeobiology of Eoconstrictor provides no evidence that pit organs played a role in the predator–prey relations of this stem boid. At the same time, the morphological diversity of Messel booids reflects the occupation of several terrestrial macrohabitats, and even in the earliest booid community the relation between pit organs and body size is similar to that seen in booids today.

APA, Harvard, Vancouver, ISO, and other styles

13

Leturcq, Philippe. "Empreinte carbone de la forêt et de l’utilisation de son bois." Revue forestière française 72, no. 6 (December 31, 2020): 525–37. http://dx.doi.org/10.20870/revforfr.2020.5348.

Full text

Abstract:

Une idée répandue est que le remplacement par du bois des combustibles fossiles et des matériaux énergivores est une meilleure stratégie pour atténuer le changement climatique que le stockage de carbone dans les forêts. Cette opinion découle de l’assertion de « neutralité carbone de la biomasse » à laquelle se réfèrent, à tort, les politiques forestière et énergétique d’un grand nombre de pays, notamment en Europe. Les objections de nombreux scientifiques sont restées jusqu’à présent sans effet, sans doute par manque d’une description suffisamment simple, compréhensible par tous, de la véritable empreinte carbone des produits ligneux récoltés. Cet article montre, à partir des fondamentaux, que l’augmentation de la récolte et des usages du bois est contre-productive pour les objectifs d’atténuation du changement climatique, notamment lorsque le bois est utilisé comme combustible.

APA, Harvard, Vancouver, ISO, and other styles

14

Biondi, Edoardo, Jean-Claude Koeniguer, and Catherine Privé-Gill. "Bois fossiles et végétations arborescentes des régions méditerranéennes durant le Tertiaire." Giornale botanico italiano 119, no. 3-4 (January 1985): 167–96. http://dx.doi.org/10.1080/11263508509428014.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Dupéron-Laudoueneix, Monique, and Jean Dupéron. "Bois fossiles de Lauraceae : nouvelle découverte au Cameroun, inventaire et discussion." Annales de Paléontologie 91, no. 2 (April 2005): 127–51. http://dx.doi.org/10.1016/j.annpal.2005.03.002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Legrand, Philippe, and Catherine Privé-Gill. "Oligocene fossil oak woods, Quercoxylon lecointrei Gazeau + Koeniguer, decayed by a pocket-rot fungus." Palaeontographica Abteilung B 289, no. 1-3 (December 7, 2012): 27–41. http://dx.doi.org/10.1127/palb/289/2012/27.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Koeniguer, J. C., and P. Louvet. "Sur la presence d'un bois de meliacees dans le tertiaire du fezzan oriental : Entandrophragmoxylon boureaui louvet." Journal of Palaeosciences 17, no. (1-3) (June 16, 2022): 33–35. http://dx.doi.org/10.54991/jop.1968.536.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Philippe, Marc. "Un déterminisme architectural pour les bois de conifères à ponctuation mixte (Protopinaceae Kraüsel, 1917)?" Canadian Journal of Botany 70, no. 9 (September 1, 1992): 1834–39. http://dx.doi.org/10.1139/b92-227.

Full text

Abstract:

The Mesozoic fossil wood assemblage, the Protopinaceae, have a type of pitting on the radial walls of their tracheids that is now almost extinct. Until now, the proposed explanations for this type of pitting were unsatisfactory. New observations show a connection with tree architecture, and a new hypothesis is proposed. Key words: Protopinaceae, Gymnosperms, Mesozoic, anatomy, architecture, morphology.

APA, Harvard, Vancouver, ISO, and other styles

19

Pailler, Delphine, René Flicoteaux, Jean-Paul Ambrosi, and Jacques Médus. "Les bois fossiles mio-pliocènes de Nkondo (lac Albert, Ouganda), composition minéralogique et mode de formation." Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 331, no. 4 (August 2000): 279–86. http://dx.doi.org/10.1016/s1251-8050(00)01413-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Williams, Jim, Peter Andrews, Sara García-Morato, Paola Villa, and Yolanda Fernández-Jalvo. "Hyena as a predator of small mammals? Taphonomic analysis from the site of Bois Roche, France." Paleobiology 44, no. 3 (May 30, 2018): 511–29. http://dx.doi.org/10.1017/pab.2018.13.

Full text

Abstract:

AbstractFeeding behaviors may differ between past and current predators due to differences in the environments inhabited by these species at different times. We provide an example of this behavioral variability in spotted hyena (Crocuta crocuta), for which our analysis of a late Pleistocene micromammal assemblage indicates that hyenas preyed upon small rodents, a feeding habit that is rarely observed today among hyenas.The Bois Roche cave site is situated at the edge of a low bluff overlooking the floodplain of a small stream in Cherves-Richemont (Charente, France). The deposits are dated by electron spin resonance (ESR) to about 69.7 ± 4.1 Ka. Excavations at the site recovered fossil bones and teeth of large and small mammals, together with hyena coprolites. Water screening of the sediments produced large accumulations of rodent remains with low taxonomic diversity. Small mammal bones were recovered from hyena coprolites as well. Descriptions of small mammal bone modification, both from the sediments and coprolites, are reported here. The analysis yielded a distinct taphonomic pattern representative of large carnivores (over 30 kg), which differs from any other modern or fossil predator-accumulated microfaunal assemblage taphonomically analyzed to date. To our knowledge, previous studies of hyena diet have not recorded high concentrations of a single-rodent prey species. We conclude that the low species diversity of this small mammal assemblage most likely relates to a local abundance of the prey species due to an outbreak in the rodent population, rather than from specialist predator behavior and hunting technique.

APA, Harvard, Vancouver, ISO, and other styles

21

Murray, Alison M., and Stephen L. Cumbaa. "New information on two Late Cretaceous (Turonian) fishes from Lac des Bois, Northwest Territories, Canada." Vertebrate Anatomy Morphology Palaeontology 1 (February 6, 2015): 23. http://dx.doi.org/10.18435/b5wc7x.

Full text

Abstract:

Fishes from Turonian deposits at Lac des Bois, Northwest Territories, Canada, have previously been described based on material from calcareous mudstone concretions collected in 1969. A more recent collecting trip to the locality in 2010 led to the discovery of fossil fishes in a shale layer. These fishes, preserved in a different manner from the earlier collections, provide new information and allow reinterpretations on two previously described fishes, Aquilopiscis wilsoni (Pachyrhizodontidae) and Avitosmerus canadensis (Euteleostei). Although the new material allows a better understanding of these two fishes, it does not change our ideas about their relationships. Avitosmerus canadensis remains in the Euteleostei with relationships uncertain, and Aquilopiscis wilsoni is confirmed as a member of the Pachyrhizodontidae.

APA, Harvard, Vancouver, ISO, and other styles

22

Cui, Qiao-Yu, Marie-José Gaillard, Boris Vannière, Daniele Colombaroli, Geoffrey Lemdahl, Fredrik Olsson, Blas Benito, and Yan Zhao. "Evaluating fossil charcoal representation in small peat bogs: Detailed Holocene fire records from southern Sweden." Holocene 30, no. 11 (July 14, 2020): 1540–51. http://dx.doi.org/10.1177/0959683620941069.

Full text

Abstract:

In this study, we assess how representative a single charcoal record from a peat profile in small bogs (1.5–2 ha in area) is for the reconstruction of Holocene fire history. We use high-resolution macrocharcoal (>250 μm) analysis of continuous series of 2 cm3 samples from two small bogs in southern Sweden. We compare (1) duplicate charcoal records from the same core, (2) duplicate charcoal records from profiles in the same site (10 m apart), and (3) charcoal records from two sites within the same region (15 km apart). Comparisons are made for charcoal counts and area expressed as accumulation rates. The results suggest that (a) charcoal counts and area are highly correlated in all records; (b) duplicate charcoal records within the same core are very similar, although some charcoal peaks are found in only one of the two records; (c) although long-term trends in fire regimes are similar between duplicate charcoal records from nearby profiles within the same site and between charcoal records from sites within the same region, some individual charcoal peaks/fire events are asynchronous between records. The known historical fires of the town of Växjö (1570 and 1612 CE) are recorded at the two study sites, which indicates a macrocharcoal source area of minimum 15 km in diameter. The 2 cm3 peat samples contained relatively low amounts of macrocharcoal; we therefore recommend to analyse larger samples from small peat bogs with comparable peat accumulation rates. This will improve the reliability of the macrocharcoal record and its interpretation.

APA, Harvard, Vancouver, ISO, and other styles

23

Ferreira, Bruno Martins, Cláudia Valéria de Lima, and Carlos Roberto dos Anjos Candeiro. "Geodiversity geological and geomorphological of the municipality of Paraúna, central-southern Goiás state, Brazil." Sociedade & Natureza 32 (August 21, 2020): 586–600. http://dx.doi.org/10.14393/sn-v32-2020-47312.

Full text

Abstract:

The research area of the present study was the municipality of Paraúna, Goiás state, Brazil, in the mesoregion of Southern Goiás, Vale do Rio dos Bois microregion. Paraúna stands out for its great tourist potential, having various tourist attractions such as the geological structure Ponte de Pedra, the mountains Serra do Galés and Serra da Portaria, among others. The State Park of Paraúna, created by the law-decree Nº 5.568 of March 18th, 2002, is also part of this municipality. This study aimed to analyze and discuss the geodiversity based on geology and geomorphology of Paraúna. The term geodiversity consists of a variety of landscapes, geological environments, rocks, soils, fossils, minerals and other surface deposits that support life on Earth. We identified and mapped seven Geodiversity sites in the northern region of Paraúna municipality.

APA, Harvard, Vancouver, ISO, and other styles

24

Janssens, Jan A., and Paul H. Glaser. "The bryophyte flora and major peat-forming mosses at Red Lake peatland, Minnesota." Canadian Journal of Botany 64, no. 2 (February 1, 1986): 427–42. http://dx.doi.org/10.1139/b86-058.

Full text

Abstract:

Red Lake peatland, a vast mire complex in northern Minnesota, contains 21 Sphagnum species, 47 other mosses, and 17 liverwort taxa in its present flora, and several other species present only as fossils in the peat. Four broad vegetation types are recognized: (i) bogs, (ii) poor fens, (iii) forested rich fens, and (iv) rich-fen pools (flarks). These vegetation types are differentiated by water chemistry and bryophyte associations. Most of the major peat-forming moss species are common, circumboreally distributed taxa, and they are distinct in their ecology. Shifts in some of their habitat requirements, however, are evident among different geographic regions of the northern hemisphere. In bogs the major peat-formers are Sphagnum species, while on minerotrophic sites in Red Lake peatland they belong mainly to the family Amblystegiaceae.

APA, Harvard, Vancouver, ISO, and other styles

25

Ryanskaya, A. D., D. V. Kiseleva, O. P. Shilovsky, and E. S. Shagalov. "XRD study of the Permian fossil bone tissue." Powder Diffraction 34, S1 (March 15, 2019): S14—S17. http://dx.doi.org/10.1017/s0885715619000174.

Full text

Abstract:

This paper is devoted to the X-ray diffraction study of bone fragments of Permian parareptile Deltavjatia vjatkensis obtained from the Kotelnich vertebrate fossil site, one of the richest of the Permian period, which is characterized by the excellent preservation of fossil remains because of their burial in a silty anaerobic environment similar to modern bogs. The bone is well-preserved and consists of fluorapatite, calcite, quartz, and dolomite. The refined apatite unit-cell parameters of a and b-axis (9.3526 ± 0.0001 and 9.3587 ± 0.0001) Å and c-axis (6.8930 ± 0.0001 and 6.8968 ± 0.0001) Å correspond to F-apatite. Crystallinity index determined as the full width at half maximum of the 002 reflection in degrees 2θ is 0.266–0.250, which is typical for Mesozoic vertebrate bones. Apatite crystallite size (length 70.3–74.9 nm, width 30.7–30.3 nm) in fossil pareiasaur bone is larger than in subfossil and recent mammal bone and is in a good agreement with the values for seismosaurus bone. Both crystallite size and aspect ratio (2.3–2.5) are independent of the fossil pareiasaur bone length.

APA, Harvard, Vancouver, ISO, and other styles

26

Foddai, Donatella, and Alessandro Minelli. "Fossil Arthropods from a Full-Glacial Site in Northeastern Italy." Quaternary Research 41, no. 3 (May 1994): 336–42. http://dx.doi.org/10.1006/qres.1994.1038.

Full text

Abstract:

AbstractFossil remains of beetles and oribatid mites from a peat deposit dated 18,870 ± 300 yr B.P. near Verona, northeastern Italy, represent the first insect fauna of its kind from the last glacial maximum to be described from Italy. The assemblage includes the ground beetle Amara alpina, whose distribution today in Europe is restricted to mountains in Scandinavia and Scotland. Ecological requirements and geographic distribution of recent populations of the identified species suggest mesic habitats with standing water and peat bogs during the glacial maximum. The paleoenvironment was comparable to present-day lowland moors in Scandinavia or mesic environments above 1000 m altitude on the southern slopes of the Alps. The climate is inferred to have been colder and wetter than today. Mean July temperature may have been 8-9°C lower than at present.

APA, Harvard, Vancouver, ISO, and other styles

27

Shotyk, William, and Tommy Noernberg. "Sampling, handling, and preparation of peat cores from bogs: review of recent progress and perspectives for trace element research." Canadian Journal of Soil Science 100, no. 4 (December 1, 2020): 363–80. http://dx.doi.org/10.1139/cjss-2019-0160.

Full text

Abstract:

Peat bogs are valuable archives of environmental change, including climate history, landscape evolution, and atmospheric deposition of trace elements, fallout radionuclides, and organic contaminants. Maintaining the fidelity of peat samples during collection and handling can be challenging, given that bogs consist mainly of fossil plant materials that typically have a very low density and are easily compressed. The surface layers of bogs, which are dominated by living plants and poorly decomposed fibrous peats, are especially problematic. To extract peat monoliths, we use a Belarus corer for deep layers and a Wardenaar device for surface layers. Both corers are constructed using titanium alloys to improve strength, reduce weight, and minimize the risk of contamination by the trace metals of environmental relevance. In this review, we include detailed drawings of the Belarus corer and photographs of the modifications to the Wardenaar corer. Modifications to the motorized Noernberg corer for frozen peat are described, and a complete set of drawings provided. A summary is given of simple procedures to minimize the risk of metal contamination in the laboratory from slicing and subsampling the peat cores and milling the dried samples.

APA, Harvard, Vancouver, ISO, and other styles

28

SKARTVEIT, JOHN, and ANDRÉ NEL. "Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits." Zootaxa 4225, no. 1 (January 23, 2017): 1. http://dx.doi.org/10.11646/zootaxa.4225.1.1.

Full text

Abstract:

All available material of fossil Bibionidae from French Oligocene localities, including the German locality of Kleinkembs right next to the border with France, is revised, and the species redescribed. Several publications (notably Heer 1856, Oustalet 1870 and Théobald 1937) have dealt with this material but there is a large degree of duplication leading to numerous synonyms. In addition, many of the named species have been assigned to the wrong genus. We have found seven species of Penthetria, eleven species of Plecia, seven species of Bibio and a single species of Dilophus in the material of previously named species. Three new species, Penthetria luberonica sp. n., Bibio aquaesextiae sp. n. and Bibiodes provincialis sp. n. are described from French Oligocene localities. The following new combinations are proposed: Penthetria claripennis (Théobald, 1937), Penthetria gigantea (Théobald, 1937), Penthetria graciliventris (Théobald, 1937), Penthetria longiventris (Théobald, 1937), Penthetria nervisinuata (Théobald, 1937), Penthetria subterranea (Théobald, 1937), Plecia morio (Heer, 1849), Bibio major (Oustalet, 1870), Dilophus luteipennis (Théobald, 1937). Many of the species occur from several outcrops, and distinctive faunas can be recognized from Early Oligocene (e.g., Célas and Monteils), Middle Oligocene (e.g., Céreste and Bois d’Asson) and Late Oligocene (e.g. Aix-en-Provence and the German outcrop of Rott). The late Oligocene localities also share some species with the Early Miocene locality of Radoboj, Croatia, but none with the younger locality of Öhningen, Southern Germany. For a number of named species, the type material is poorly preserved and cannot be recognized at the species level, these are commented on and assigned to the lowest taxonomical level to which they can be identified with certainty. The type materials of a number of species appear to be lost; these are placed to genera to the extent that this is possible from the original descriptions and illustrations. Bibio nigripennis Théobald, 1937, nec Brunetti, 1913 is a primary junior homonym and the name must be replaced. The species is moved to the genus Plecia and renamed Plecia theobaldi nom.n.

APA, Harvard, Vancouver, ISO, and other styles

29

Ye, Zhencheng, Xiaoyan Mo, and Liang Zhao. "MINLP Model for Operational Optimization of LNG Terminals." Processes 9, no. 4 (March 30, 2021): 599. http://dx.doi.org/10.3390/pr9040599.

Full text

Abstract:

Liquefied natural gas (LNG) is a clear and promising fossil fuel which emits less greenhouse gas (GHG) and has almost no environmentally damaging sulfur dioxide compared with other fossil fuels. An LNG import terminal is a facility that regasifies LNG into natural gas, which is supplied to industrial and residential users. Modeling and optimization of the LNG terminals may reduce energy consumption and GHG emission. A mixed-integer nonlinear programming model of the LNG terminal is developed to minimize the energy consumption, where the numbers of boil-off gas (BOG) compressors and low-pressure (LP) pumps are considered as integer variables. A case study from an actual LNG terminal is carried out to verify the practicality of the proposed method. Results show that the proposed approach can decrease the operating energy consumption from 9.15% to 26.1% for different seasons.

APA, Harvard, Vancouver, ISO, and other styles

30

Kuder, Tomasz, and Michael A. Kruge. "Preservation of biomolecules in sub-fossil plants from raised peat bogs — a potential paleoenvironmental proxy." Organic Geochemistry 29, no. 5-7 (November 1998): 1355–68. http://dx.doi.org/10.1016/s0146-6380(98)00092-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Šīre, Jānis, Māris Kļaviņš, Oskars Purmalis, and Viesturs Melecis. "Experimental Study of Peat Humification Indicators." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 62, no. 1-2 (January 1, 2008): 18–26. http://dx.doi.org/10.2478/v10046-008-0009-y.

Full text

Abstract:

Experimental Study of Peat Humification Indicators An important parameter of organic matter in soils, peat, and fossil-carbon-containing deposits is their decomposition degree, which describes their transformation intensity—the humification degree of original living organic matter. In this article approaches to the analysis of humification degree are thoroughly described and14C dated peat columns extracted from several bogs in Latvia are investigated and compared. A new humification indicator is suggested: the ratio of the total amount of organic matter in peat in respect to the amount of humic substances.

APA, Harvard, Vancouver, ISO, and other styles

32

Payette, Serge, and Roxane Lajeunesse. "Les combes à neige de la rivière aux Feuilles (Nouveau-Québec) : indicateurs paléoclimatiques holocènes." Géographie physique et Quaternaire 34, no. 2 (January 28, 2011): 209–20. http://dx.doi.org/10.7202/1000398ar.

Full text

Abstract:

L’analyse des sols et de la végétation de ces milieux a permis de situer leur origine et leur évolution au cours du Néoglaciaire. La présence de macrorestes fossiles (charbons de bois, cônes calcinés d’épinette noire Picea mariana (Mill)) BSP et de mélèze Larix laricina (DuRoi) K. Koch, fragments de bois) indique que les combes à neige viennent de milieux anciennement boisés. La disparition du couvert forestier se serait produite à la suite de feux survenant au cours de périodes climatiques froides inhibant toute régénération forestière. Les combes à neige sont ainsi la réponse à des périodes de détérioration climatique qui se sont manifestées quelque temps après 2600, 2200, 1600-1400, 1000-900 et 500-300 ans BP. Quelques combes à neige apparues tôt au Néoglaciaire auraient connu une régression autour de 1300-1200 ans BP (sous réserve), grâce à un réchauffement climatique ayant favorisé une certaine réafforestation. L’apparition et l’expansion graduelles des combes à neige aux dépens du couvert forestier de 2600 ans BP jusqu’à nos jours suggèrent que le refroidissement climatique, bien que persistant, n’était pas de grande amplitude; les feux auraient servi la plupart du temps d’amorce à l’expansion du couvert de neige. Les combes à neige situées à proximité de formations arborescentes ont subi un envahissement de mélèzes entre 1940 et 1970, corrélé avec le réchauffement climatique du XXe siècle. Depuis 1970, un renversement de la tendance climatique est survenu et est caractérisé par la mortalité d’au moins 17 % de la population de mélèzes des combes à neige. Cette mortalité est étroitement reliée à l’intense reprise des processus périglaciaires dans les combes. Finalement, l’apparition toute récente de grandes coulées de gélifiluction sur les versants enneigés a eu pour conséquence de détruire la végétation des bas-versants et favoriser la formation de nouvelles combes à neige.

APA, Harvard, Vancouver, ISO, and other styles

33

Albright, L. Barry. "Lower vertebrates from an Arikareean (earliest Miocene) fauna near the Toledo Bend Dam, Newton County, Texas." Journal of Paleontology 68, no. 5 (September 1994): 1131–45. http://dx.doi.org/10.1017/s002233600002672x.

Full text

Abstract:

A recently discovered vertebrate fossil-bearing locality in the Fleming Formation of easternmost Texas has revealed a highly diverse fauna that contains a minimum of 44 early Miocene vertebrate taxa. At least 17 different species of lower vertebrates were recovered including five fish, two amphibians, one lizard, two snakes, at least five chelonians, and two crocodilians. A tiny boid that compares favorably with Anilioides nebraskensis is the first record in the Gulf Coastal Plain, and remains of a large aquatic turtle referred to the genus Dermatemys possibly represent its first fossil occurrence. Other rare genera represented include the largemouth bass Micropterus, possibly the snook Centropomus, and the crocodilian Gavialosuchus. In addition, temporal and spatial range extensions are recorded for Micropterus and Alligator olseni. These taxa, along with the mammalian component to be discussed elsewhere, document the rare preservation of a forested subtropical to tropical coastal lowland paleoenvironment and provide evidence to imply that separation into mid-continent and coastal plain paleobiogeographic provinces had not yet occurred.

APA, Harvard, Vancouver, ISO, and other styles

34

Fielitz, Christopher. "A new Late Cretaceous (Turonian) basal euteleostean fish from Lac des Bois of the Northwest Territories of Canada." Canadian Journal of Earth Sciences 39, no. 11 (November 1, 2002): 1579–90. http://dx.doi.org/10.1139/e02-061.

Full text

Abstract:

A new genus and species of Late Cretaceous euteleost, Avitosmerus canadensis, is described from an assemblage of fossil fishes found in a Late Cretaceous (Turonian) unnamed member (unit E) of the Great Bear Basin from Lac des Bois, Northwest Territories, Canada. It is a small fusiform fish characterized by a long slender supraorbital, the presence of a small suprapreopercle, branches of the preopercular sensory canal that reach the edge of the preopercle, and an anterior supraneural that is twice as large as those posterior to it. Additionally, elements of its caudal fin show a high degree of fusion. Avitosmerus is one of ten described Cretaceous basal euteleosts that are found worldwide (Avitosmerus, Barcarenichthys, Erichalcis, Gaudryella, Gharbouria, Humbertia, Kermichthys, Manchurichthys, Paravinciguerria, and Stompooria). Avitosmerus and Erichalcis are the only two basal euteleosts that have been described from the Cretaceous of North America. Placement of Avitosmerus into the Euteleostei is based on the presence of a free stegural, and the large first supraneural. Both of these characters are somewhat controversial and are in need of reexamination. Avitosmerus shares a number of characters with the other Cretaceous basal euteleosts, as well as Recent basal euteleosts, including a separate rostrodermethmoid and mesethmoid (Gaudryella, Erichalcis, Gharbouria, the Osmeridae, and the Coregonidae), lobate condyles of the hyomandibula (Avitosmerus, Gaudryella, and Gharbouria), leaf-shaped neural spine on the first preural centrum (Kermichthys), and the fusion of the parhypural, first, and second hypurals (Gaudryella).

APA, Harvard, Vancouver, ISO, and other styles

35

Moreau, Jean-David, Didier Néraudeau, and Vincent Perrichot. "Conifers from the Cenomanian amber of Fouras (Charente-Maritime, western France)." BSGF - Earth Sciences Bulletin 191 (2020): 16. http://dx.doi.org/10.1051/bsgf/2020017.

Full text

Abstract:

Fossil inclusions of arthropods and microorganisms are abundant in the Cretaceous amber from western France, but plant meso- or macroremains are scarce. Preserved remains are mostly tiny, very fragmented, and indeterminable. Only one amber locality in the Charente department has already provided conifer remains. Here, we report the first plant mesoremains ensnared in Cenomanian amber from Fouras – Bois Vert, in the Charente-Maritime department. They consist of three well-preserved leafy axes and one cone of Cheirolepidiacean conifers. Based on the helical arrangement of rhomboidal, longer than wide, and highly adpressed leaves, leafy axes are ascribed to the genus Pagiophyllum. The ovoid cone bears more than 15 imbricate, helically arranged, scale-like leaves and is ascribed to Classostrobus sp. Although Cretaceous flora is abundant in lignitic clay from the Charentes region, Pagiophyllum is reported for the first time in Albian-Cenomanian deposits from this area. Xerophytic features of Pagiophyllum further support a harsh and instable coastal environment seasonally exposed to hot, dry conditions during the mid-Cretaceous in the Charentes region.

APA, Harvard, Vancouver, ISO, and other styles

36

Sass-Klaassen, U., I. Poole, T. Wils, G. Helle, G. H. Schleser, and P. F. van Bergen. "Carbon and Oxygen Isotope Dendrochronology in Sub-Fossil Bog Oak Tree Rings - A Preliminary Study." IAWA Journal 26, no. 1 (2005): 121–36. http://dx.doi.org/10.1163/22941932-90001607.

Full text

Abstract:

Isotope dendroclimatology is a relatively new field investigating environmental factors that control the radial growth of trees. Tree-ring series of sub-fossil bog oaks can be dated from sites across northwest Europe indicating that the environmental change(s) were regional rather than local. Bog oaks show characteristic periods of suppressed growth thought to have resulted from changes in the hydrological status of bogs towards either wetter or drier conditions. This study investigates relative changes in stable carbon (δ13C) and oxygen (δ18O) isotope content in phases of suppressed and normal growth in three bog oaks dated as c. 200 BC to 150 AD from Zwolle, eastem Netherlands. Bog oaks show no clear relationship between tree-ring width and isotopic composition although one tree exhibited relatively depleted values of l3C and 18O with suppressed growth. Suppressed ring growth is characterised by the formation of earlywood only, possibly as a result ofhydrologic alterations that limited the formation of latewood, which would otherwise have locked up a detectable signal in stable isotopic shift.

APA, Harvard, Vancouver, ISO, and other styles

37

Nordlund, Christer. "Peat bogs as geological archives: Lennart Von Post et al., and the development of quantitative pollen analysis during World War I." Earth Sciences History 33, no. 2 (January 1, 2014): 187–200. http://dx.doi.org/10.17704/eshi.33.2.b9058l3153638715.

Full text

Abstract:

In 1916, at the 16th Convention of Scandinavian Naturalists in Kristiania (Oslo), a novel quantitative method for the analysis of postglacial vegetation and climate history was presented. The idea behind the method, later known as pollen analysis, was to utilize peat bogs as geological archives and fossil tree pollen stored in such archives as data. In the historiography of palynology, this lecture by the Swedish geologist Lennart von Post (1884-1951) remains a classic. Pollen from postglacial deposits had indeed been used before, but the approach represented a breakthrough through the launch of the so-called pollen diagram, by which it was possible to summarize and visualize a large amount of data. In the present essay, certain aspects of the intellectual, social and material context of von Post's work are explored. I argue that the aim of the pollen analytical method was to solve Quaternary geological problems rather than biological, and that the method's empirical foundation was connected to an extensive survey of peat bogs, conducted in order to secure energy supply during the First World War. Furthermore, although the method soon won adherents within the scientific community, it is demonstrated in the essay that it did not receive unanimous approval.

APA, Harvard, Vancouver, ISO, and other styles

38

Vargot, E. V., O. G. Grishutkin, and O. N. Artaev. "RESULTS OF INVESTIGATIONS OF WETLANDS KRYACHEK LAKE AND NEIGHBORHOOD (ULYANOVSK REGION)." Samara Journal of Science 4, no. 2 (June 15, 2015): 41–45. http://dx.doi.org/10.17816/snv20152111.

Full text

Abstract:

Paper presents materials of comprehensive research (physical-geographical characteristics, plant cover, ichtyofauna) of Kryachek (Kryazh) Lake and of three worked-out bogs (Stanovoe, Lebyazhye and unnamed in 2 km to east of the Lyakhovka village) located near this lake. At present, all investigated water bodies are lakes with a more or less developed sphagnum-sedge, serge-calamagrostis-sphagnum quaking mires. Physiographic characteristics (surface of bottom for Kryachek Lake, pH of water, depth of lakes), plant cover and ichthyofauna of lakes were studied during researches. It was revealed that Kryachek Lake and depleted peatlands have a high floristic diversity relatively to other similar ecosystem (lakes, raised bogs and transition mires). Altogether 77 species of vascular plants from 48 genera and 32 families were revealed within studied objects. Among the studied flora, species of ferns, raised bogs, transition mires and, also, aquatic andlittoral-aquatic plant species are presented due to the presence of various microecotopes (young and formed quaking mires of raised bogs and transitional mires, fens, ditches, backwaters, shallow waters, deep areas). Studied wetlands are places of location many rare plants in forest-steppe-Potamogeton obtusifolius Mert. et Koch, P. praelongus Wulf., Scheuchzeria palustris L., Eriophorum gracile Koch, Carex chordorrhiza Ehrh., C. limosa L., Hammarbya paludosa (L.) O. Kuntze, Salix lapponum L., S. myrtilloides L., Drosera rotundifolia L., Oxycoccus palustris Pers., Utricularia intermedia Hayne, U. minor L. Ichthyofauna of studied water bodies with sphagnum quaking mire is very poor. Altogether, four limnophilic fish species were registered (Leucaspius delineatus (Heckel, 1843), Carassius auratus (Linnaeus, 1758), C. carassius (Linnaeus, 1758), Misgurnus fossilis (Linnaeus, 1758)). This is explained by the peculiarities of physical-chemical environment settings (in particular, it is the dynamics of pH in the range of 4,3-6,4 within a water body) and a considerable distance from the rivers which are the main source of resettlement of different fish species.

APA, Harvard, Vancouver, ISO, and other styles

39

Maurel, Lionel. "Des communs positifs aux communs négatifs." Multitudes 93, no. 4 (December 14, 2023): 56–61. http://dx.doi.org/10.3917/mult.093.0056.

Full text

Abstract:

La notion de Communs s’est dans une grande mesure diffusée dans la littérature académique en France à partir des travaux de l’économiste Elinor Ostrom autour des Commons Pool Resources . Dans cette conception, les Communs sont toujours des éléments intrinsèquement marqués positivement, en tant qu’ils constituent des biens pourvus d’utilités venant satisfaire des besoins humains (réserves en eau, bois, ressources halieutiques, etc.). Cette vision a permis un temps une meilleure prise en compte des questions écologiques dans le champ de l’économie, en mettant en lumière des pratiques de gestion partagée pouvant contribuer, dans certaines conditions, à la durabilité des ressources. Mais elle est aussi fortement marquée par une perspective « environnementaliste » et « développementiste » peu adaptée à la situation ouverte par l’Anthropocène et les défis qui la caractérisent. Dans un monde marqué par l’urgence climatique, il importe sans doute de rompre avec l’approche « bucolique » des communs positifs pour envisager en tant que Communs négatifs non plus les choses suscitant un désir d’appropriation, mais celles que plus personne au contraire ne souhaite posséder (déchets, ruines industrielles). Penser les Communs au-delà de la ressource et de l’usage permet aussi de penser comme Communs négatifs des éléments dont l’abandon ou la limitation devient critique (énergies fossiles, plastique, viande, trafic aérien, etc.).

APA, Harvard, Vancouver, ISO, and other styles

40

Stamatakis, Michael E., Erofili E. Stamataki, Anastasios P. Stamelos, and Maria G. Ioannides. "Energy Management in a Super-Tanker Powered by Solar, Wind, Hydrogen and Boil-Off Gas for Saving CO2 Emissions." Electronics 13, no. 8 (April 19, 2024): 1567. http://dx.doi.org/10.3390/electronics13081567.

Full text

Abstract:

In terms of energy generation and consumption, ships are autonomous isolated systems, with power demands varying according to the type of ship: passenger or commercial. The power supply in modern ships is based on thermal engines-generators, which use fossil fuels, marine diesel oil (MDO) and liquefied natural gas (LNG). The continuous operation of thermal engines on ships during cruises results in increased emissions of polluting gases, mainly CO/CO2. The combination of renewable energy sources (REs) and triple-fuel diesel engines (TFDEs) can reduce CO/CO2 emissions, resulting in a “greener” interaction between ships and the ecosystem. This work presents a new control method for balancing the power generation and the load demands of a ship equipped with TFDEs, fuel cells (FCs), and REs, based on a real and accurate model of a super-tanker and simulation of its operation in real cruise conditions. The new TFDE technology engines are capable of using different fuels (marine diesel oil, heavy fuel oil and liquified natural gas), producing the power required for ship operation, as well as using compositions of other fuels based on diesel, aiming to reduce the polluting gases produced. The energy management system (EMS) of a ship is designed and implemented in the structure of a finite state machine (FSM), using the logical design of transitions from state to state. The results demonstrate that further reductions in fossil fuel consumption as well as CO2 emissions are possible if ship power generation is combined with FC units that consume hydrogen as fuel. The hydrogen is produced locally on the ship through electrolysis using the electric power generated by the on-board renewable energy sources (REs) using photovoltaic systems (PVs) and wind energy conversion turbines (WECs).

APA, Harvard, Vancouver, ISO, and other styles

41

Head, Jason J. "The Neogene Fossil Record of Rubber Boas (Serpentes: Boidae: Charina) Tests Hypotheses of Ecological Niche Conservation and Relationship to Climate." Paleontological Society Special Publications 13 (2014): 58–59. http://dx.doi.org/10.1017/s2475262200011254.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Néraudeau, Didier, Ronan Allain, Vincent Perrichot, Blaise Videt, France de Lapparent de Broin, François Guillocheau, Marc Philippe, Jean-Claude Rage, and Romain Vullo. "Découverte d’un dépôt paralique à bois fossiles, ambre insectifère et restes d’Iguanodontidae (Dinosauria, Ornithopoda) dans le Cénomanien inférieur de Fouras (Charente-Maritime, Sud-Ouest de la France)." Comptes Rendus Palevol 2, no. 3 (April 2003): 221–30. http://dx.doi.org/10.1016/s1631-0683(03)00032-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Zin, Nurul Aisyah Mohd, and Shaharin Anwar Sulaiman. "Operating Characteristics of Gasifier Cookstove Using Different Biomass Materials." Applied Mechanics and Materials 393 (September 2013): 516–21. http://dx.doi.org/10.4028/www.scientific.net/amm.393.516.

Full text

Abstract:

Biomass energy technology such as gasifier is increasingly receiving attention as a promising renewable energy source because of the ever rising costs of fossils fuels especially diesel and kerosene. Gaseous products of gasifier based cookstove are relatively clean and environmental friendly than direct combustion cookstove. The objective of this workwas to characterize the basic operating properties of a gasifier-based biomass cookstove using different types of biomass fuels. The main characteristics evaluated were the efficiencyof the stove. The biomass considered were oil palm fronds, dry leaves and pressed sugarcane. The efficiency of the stove was tested using water boiling tests.Other characteristics such as its ignition duration and the time required to boil 2.5 kg of water were also observed. The performance of each fuel was studied by analyzing the parameters involved during water boiling tests. It was found that oil palm frond has the highest thermal efficiency among all the fuels tested.

APA, Harvard, Vancouver, ISO, and other styles

44

Yu, Peng, Yuanchao Yin, Qianjin Yue, and Shanghua Wu. "Experimental Study of Ship Motion Effect on Pressurization and Holding Time of Tank Containers during Marine Transportation." Sustainability 14, no. 6 (March 18, 2022): 3595. http://dx.doi.org/10.3390/su14063595.

Full text

Abstract:

Liquefied natural gas (LNG) is the cleanest fossil fuel available, producing less carbon emissions and fewer pollutants than other fossil fuels. Marine transportation is a key process in the LNG supply chain. The use of tank containers, which are portable equipment, can effectively facilitate multi-mode transportation. LNG evaporation causes pressurization, which is a safety concern during transportation. Ship motion and environmental temperature are the main factors affecting pressure variations. In this study, the effect of ship motion on pressurization and holding time was investigated through three types of experiments, namely, prototype, field, and self-pressurization experiments. The results showed that while increased boil-off gas was generated due to ship motion, this evaporation remained stable in dynamic cases. Higher evaporation rates were obtained under more severe dynamic conditions, and the holding time was shortened. The two different effects of ship motion on pressure development discussed here are the facilitation of pressurization due to the enhancement of heat transfer and the prevention of pressurization due to gas condensation at the vapor–liquid interface. These two effects show varied levels of predominance over the pressure variations depending on different stages of transportation. The holding time in the experiments was able to reach 87 days under the most severe condition, which is long enough for long-term shipping; the safety of transporting LNG in tank containers is further discussed based on the experimental results herein.

APA, Harvard, Vancouver, ISO, and other styles

45

Azuara, Julien, Florence Mazier, Vincent Lebreton, Shinya Sugita, Nicolas Viovy, and Nathalie Combourieu-Nebout. "Extending the applicability of the REVEALS model for pollen-based vegetation reconstructions to coastal lagoons." Holocene 29, no. 7 (April 15, 2019): 1109–12. http://dx.doi.org/10.1177/0959683619838024.

Full text

Abstract:

Quantitative reconstruction of past plant abundance from fossil pollen data is still a challenging task for palynologists. During the last decades, mechanistic methods have been developed to convert pollen assemblages from peat and lake deposits into vegetation abundance at regional and local scale. Coastal areas are particularly sensitive to climate and environmental hazards. Thus, quantitative estimates of past vegetation are important to better understand their history and address potential effects of future environmental changes. However, assumptions of the mechanistic models of pollen dispersal and deposition originally designed for near-circular lakes and bogs located inland are violated when applied to coastal sites because of different basin shape and wind direction distribution. This study investigates how to adapt a model of pollen dispersal and deposition developed for lakes to coastal lagoons. A new geometry is defined, and it is demonstrated how some of the major formulas from previous models can be used without any modification in this singular context.

APA, Harvard, Vancouver, ISO, and other styles

46

Jankovská, Vlasta, Milena Roszkowska, and Łukasz Kaczmarek. "Remains of non-pollen-palynomorphs – tardigrades from Spitsbergen found during pollen analyses." Polar Record 52, no. 4 (March 7, 2016): 450–63. http://dx.doi.org/10.1017/s0032247416000127.

Full text

Abstract:

ABSTRACTPollen- and non-pollen-palynomorphs (NPP) analytical studies of the northwestern part of Spitsbergen were conducted between 1988 and 1991. As well as pollen from local native flora and more dispersed species, some well preserved remains of tardigrada exuvia, buccal tubes and eggs were found. This study reviewed the remains of at least six tardigrade taxa reported:Dactylobiotus ambiguous, Paramacrobiotus richtersigroup,Richtersius coronifer, Macrobiotus hufelandigroup,Macrobiotus peterseniandMinibiotuscf.intermedius, which are reassessed and determined more accurately. These findings provide some new insights into the past environmental conditions and changes for Spitsbergen. Based on the present research it can be concluded that tardigrade remains are frequent NPP elements of pollen analyses from lake, peat bogs and detritus sub-fossil sediment cores, at least in polar regions. It can also be stated that tardigrades can be considered indicators in further palaeontological studies helping to reconstruct past environmental conditions (for example humidity) for some regions. However, the knowledge of tardigrades in these types of analyses is still rather poor.

APA, Harvard, Vancouver, ISO, and other styles

47

Williams, Frank L’Engle, Katherine M. Lane, and William G. Anderson. "Comparison of maxillary first molar occlusal outlines of Neandertals from the Meuse River Basin of Belgium using elliptical Fourier analysis." Anthropological Review 80, no. 3 (September 1, 2017): 273–86. http://dx.doi.org/10.1515/anre-2017-0018.

Full text

Abstract:

AbstractSeveral Neandertals derive from the karstic caves of the Meuse river tributaries of Belgium, including Engis 2, Scladina 4A-4 and Spy 1. These may form a group that is distinct in maxillary first molar occlusal outlines compared to La Quina 5 from Southwest France. Alternatively, chronological differences may separate individuals given that Scladina 4A-4 from MIS 5 is older than the others from MIS 3. Neolithic samples (n = 42) from Belgium (Maurenne Caverne de la Cave, Hastière Caverne M, Hastière Trou Garçon, Sclaigneaux and Bois Madame) dated to 4.6–3.9 kyr provide a context for the Neandertals. Dental casts were prepared from dental impressions of the original maxillary molars. Crown and occlusal areas as well as mesiodistal lengths were measured by calibrated Motic 3.0 microscope cameras. Occlusal outlines of the casts were captured through photostereomicroscopy and non-landmark smooth tracing methods. Occlusal outlines were processed using elliptical Fourier analysis within SHAPE v1.3 which reduced amplitudes of the harmonics into principal components (PC) axes. The first two PC axes group the Neandertals, although Scladina 4A-4 falls nearly outside the convex hull for the Neolithic sample. Neandertals are imperfectly separated from the Neolithic sample on PC3 and PC4, and completely distinct on PC5 and PC6. Scladina 4A-4 differs from the other Neandertals on most PC axes. Chronology may best explain the separation of Scladina 4A-4 from the more recent fossils, and particularly Spy 1 and La Quina 5 which are the most similar in maxillary first molar occlusal outline shape.

APA, Harvard, Vancouver, ISO, and other styles

48

Linganiso, Ella Cebisa, Boitumelo Tlhaole, Lindokuhle Precious Magagula, Silas Dziike, Linda Zikhona Linganiso, Tshwafo Elias Motaung, Nosipho Moloto, and Zikhona Nobuntu Tetana. "Biodiesel Production from Waste Oils: A South African Outlook." Sustainability 14, no. 4 (February 10, 2022): 1983. http://dx.doi.org/10.3390/su14041983.

Full text

Abstract:

The viability of large-scale biodiesel production ultimately boils down to its cost of commercialisation despite other very important factors such as the negative environmental and health effects caused by the direct combustion of fossil diesel. How much each country’s economy will be influenced by the production of biodiesel will be determined by the commitment of various stakeholders to the much-needed transition from petroleum-based resources to renewable resources. Biodiesel production is largely determined by the cost of the feedstock (>70%) and this review focuses on the use of waste oil resources as biodiesel feedstock with a special focus on waste cooking oil (WCO). Generating value from waste oil provides an alternative waste management route as well as a positive environmental and economic contribution. The transesterification process for biodiesel production, its catalysis and some important technical and economic aspects are covered in this communication with a special focus on the South African framework. An overview of the current research and its implications going forward is discussed.

APA, Harvard, Vancouver, ISO, and other styles

49

Väliranta, Minna, Niina Salojärvi, Annina Vuorsalo, Sari Juutinen, Atte Korhola, Miska Luoto, and Eeva-Stiina Tuittila. "Holocene fen–bog transitions, current status in Finland and future perspectives." Holocene 27, no. 5 (October 5, 2016): 752–64. http://dx.doi.org/10.1177/0959683616670471.

Full text

Abstract:

Minerotrophic fens and ombrotrophic bogs differ in their nutrient status, hydrology, vegetation and carbon dynamics, and their geographical distribution is linked to various climate parameters. Currently, bogs dominate the northern temperate and southern boreal zones but climate warming may cause a northwards shift in the distribution of the bog zone. To more profoundly understand the sensitivity of peatlands to changes in climate, we first used the plant macrofossil method to identify plant communities that are characteristic of past fen–bog transitions. These transitions were radiocarbon dated, to be linked to Holocene climate phases. Subsequently, palaeoecological data were combined with an extensive vegetation survey dataset collected along the current fen–bog ecotone in Finland where we studied how the distribution of the key plant species identified from peat records is currently related to the most important environmental variables. The fossil plant records revealed clear successional phases: an initial Carex-dominated fen phase, an Eriophorum vaginatum–dominated oligotrophic fen phase followed by an early bog phase with wet bog Sphagna. This was occasionally followed by a dry ombrotrophic bog phase. Timing of initiation and phase transitions, and duration of succession phases varied between three sites studied. However, the final ombrotrophication occurred during 2000–3000 cal. BP corresponding to the neoglacial cooling phase. Dry mid-Holocene seems to have facilitated initiation of Eriophorum fens. The peatlands surveyed in the fen–bog ecotone were classified into succession phases based on the key species distribution. In 33% of the studied peatlands, Sphagnum had taken over and we interpret they are going through a final transition from fen to bog. In addition to autogenic processes and direct climate impact, our results showed that ecosystem shifts are also driven by allogenic disturbances, such as fires, suggesting that climate change can indirectly assist the ombrotrophication process in the southern border of the fen–bog ecotone.

APA, Harvard, Vancouver, ISO, and other styles

50

ÁBRAHÁM, Beáta, Ildikó MIKLÓSSY, Erika KOVÁCS, Éva TAMÁS, Ildikó MÉSZÁROS, Szabolcs SZILVESZTER, Aurelia BREZEANU, and Szabolcs LÁNYI. "Genetic Analysis of Pinus sylvestris L. and Pinus sylvestris forma turfosa L. Using RAPD Markers." Notulae Scientia Biologicae 2, no. 1 (March 9, 2010): 129–32. http://dx.doi.org/10.15835/nsb213611.

Full text

Abstract:

The purpose of the present study was to determine the level of genetic diversity within and among Ciuc basin, Romania (populations from Mohos and Luci raised bogs in Harghita Mountain and Sumuleu in Ciuc Mountain) Pinus sylvestris populations using molecular markers. Two of populations (Mohos and Luci) seems to be the descendants that survived the continental glaciation. Genetic diversity was analyzed by RAPD (Random Amplified Polymorphic DNA). Nine primers were selected for analysis, which generated reproducible bands. On base of presence or absence of homologues bands Nei’s gene diversity, the percentage of polymorphic loci and Nei’s unbiased genetic distance were calculated. The level of genetic variation among populations was found to be low. For both populations the variation values among populations were higher than within populations. The fossil records and geological historical data explain the extremely low genetic diversity of this species. Pinus sylvestris experienced strong bottlenecks during its evolutionary history, which caused the loss of genetic variation. Genetic drift and breeding in post-bottlenecked small populations may be the major forces that contribute to low genetic diversity and genetic differentiation of populations. Human activities may have accelerated the loss of genetic diversity in Pinus sylvestris.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Bois fossile'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles