Relevant bibliographies by topics / Front polaire

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  2. Dissertations / Theses
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Academic literature on the topic 'Front polaire'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 July 2024

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Journal articles on the topic "Front polaire"

1

Donguy, Patrick. "Novembre 1992 : Bande nuageuse du front polaire du front polaire." La Météorologie 8, no. 1 (1993): 124. http://dx.doi.org/10.4267/2042/53346.

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Thillet, Jean-Jacques. "Débat sur le front polaire." La Météorologie 8, no. 12 (1995): 58. http://dx.doi.org/10.4267/2042/52006.

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LEROUX, Marcel. "Commentaire sur « Débat sur le front polaire » de J.-J. Thillet et A. Joly (La Météorologie 8e série, n° 12, décembre 1995, 58-67)." La Météorologie 8, no. 16 (1996): 49. http://dx.doi.org/10.4267/2042/47004.

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Kerr, Bethany A. "Immunomodulation in the front, bone-binding in the back." Science Translational Medicine 12, no. 528 (January 29, 2020): eaba2917. http://dx.doi.org/10.1126/scitranslmed.aba2917.

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Lou, Sunny S., Alba Diz-Muñoz, Orion D. Weiner, Daniel A. Fletcher, and Julie A. Theriot. "Myosin light chain kinase regulates cell polarization independently of membrane tension or Rho kinase." Journal of Cell Biology 209, no. 2 (April 27, 2015): 275–88. http://dx.doi.org/10.1083/jcb.201409001.

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Cells polarize to a single front and rear to achieve rapid actin-based motility, but the mechanisms preventing the formation of multiple fronts are unclear. We developed embryonic zebrafish keratocytes as a model system for investigating establishment of a single axis. We observed that, although keratocytes from 2 d postfertilization (dpf) embryos resembled canonical fan-shaped keratocytes, keratocytes from 4 dpf embryos often formed multiple protrusions despite unchanged membrane tension. Using genomic, genetic, and pharmacological approaches, we determined that the multiple-protrusion phenotype was primarily due to increased myosin light chain kinase (MLCK) expression. MLCK activity influences cell polarity by increasing myosin accumulation in lamellipodia, which locally decreases protrusion lifetime, limiting lamellipodial size and allowing for multiple protrusions to coexist within the context of membrane tension limiting protrusion globally. In contrast, Rho kinase (ROCK) regulates myosin accumulation at the cell rear and does not determine protrusion size. These results suggest a novel MLCK-specific mechanism for controlling cell polarity via regulation of myosin activity in protrusions.
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PARR, HELEN. "The British Decision to Upgrade Polaris, 1970–4." Contemporary European History 22, no. 2 (April 4, 2013): 253–74. http://dx.doi.org/10.1017/s0960777313000076.

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AbstractThis article adopts a political approach to examine the reasons why Edward Heath's government wanted to upgrade Polaris and the reasons why they did so by way of a programme called Super Antelope, to improve the front-ends of the missiles against Soviet Anti-Ballistic Missile defence, as opposed to the alternatives on offer. It argues that the political contexts within which Heath took the decision have been insufficiently understood, and shows that the acceptance of the ‘Moscow criterion’ – the understanding that Britain had to have the capability to destroy Moscow – by central government represented continuity in Britain's cold war stance.
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Wong, Kit, Alexandra Van Keymeulen, and Henry R. Bourne. "PDZRhoGEF and myosin II localize RhoA activity to the back of polarizing neutrophil-like cells." Journal of Cell Biology 179, no. 6 (December 17, 2007): 1141–48. http://dx.doi.org/10.1083/jcb.200706167.

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Chemoattractants such as formyl-Met-Leu-Phe (fMLP) induce neutrophils to polarize by triggering divergent pathways that promote formation of a protrusive front and contracting back and sides. RhoA, a Rho GTPase, stimulates assembly of actomyosin contractile complexes at the sides and back. We show here, in differentiated HL60 cells, that PDZRhoGEF (PRG), a guanine nucleotide exchange factor (GEF) for RhoA, mediates RhoA-dependent responses and determines their spatial distribution. As with RNAi knock-down of PRG, a GEF-deleted PRG mutant blocks fMLP-dependent RhoA activation and causes neutrophils to exhibit multiple fronts and long tails. Similarly, inhibition of RhoA, a Rho-dependent protein kinase (ROCK), or myosin II produces the same morphologies. PRG inhibition reduces or mislocalizes monophosphorylated myosin light chains in fMLP-stimulated cells, and myosin II ATPase inhibition reciprocally disrupts normal localization of PRG. We propose a cooperative reinforcing mechanism at the back of cells, in which PRG, RhoA, ROCK, myosin II, and actomyosin spatially cooperate to consolidate attractant-induced contractility and ensure robust cell polarity.
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A. Davis, PharmD, BCOP, James, Abigail Shockley, PharmD, Amanda Herbst, PA-C, and Lindsey Hendrickson, DNP, APRN, FNP-C. "Polatuzumab Vedotin for the Front-Line Treatment of Diffuse Large B-Cell Lymphoma: A New Standard of Care?" Journal of the Advanced Practitioner in Oncology 14, no. 1 (January 1, 2023): 67–72. http://dx.doi.org/10.6004/jadpro.2023.14.1.6.

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Diffuse large B-cell lymphoma (DLBCL) is the most common type of aggressive non-Hodgkin lymphoma in the US. For nearly 2 decades, standard front-line treatment has consisted of chemoimmunotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Numerous trials have unsuccessfully attempted to achieve better outcomes in these patients. Recently, the results of the phase III POLARIX trial were published. This study randomized newly diagnosed DLBCL patients to receive polatuzumab vedotin in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (pola-R-CHP) or standard-of-care R-CHOP. The POLARIX trial demonstrated 2-year progression-free survival of 76.7% for pola-R-CHP compared with 70.2% for R-CHOP with comparable safety profiles between the two arms. Based on these results, a new standard of care may be emerging in patients with DLBCL. This article provides a practical approach to managing a newly diagnosed patient with DLBCL.
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Town, Jason P., and Orion D. Weiner. "Local negative feedback of Rac activity at the leading edge underlies a pilot pseudopod-like program for amoeboid cell guidance." PLOS Biology 21, no. 9 (September 25, 2023): e3002307. http://dx.doi.org/10.1371/journal.pbio.3002307.

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To migrate efficiently, neutrophils must polarize their cytoskeletal regulators along a single axis of motion. This polarization process is thought to be mediated through local positive feedback that amplifies leading edge signals and global negative feedback that enables sites of positive feedback to compete for dominance. Though this two-component model efficiently establishes cell polarity, it has potential limitations, including a tendency to “lock” onto a particular direction, limiting the ability of cells to reorient. We use spatially defined optogenetic control of a leading edge organizer (PI3K) to probe how neutrophil-like HL-60 cells balance “decisiveness” needed to polarize in a single direction with the flexibility needed to respond to new cues. Underlying this balancing act is a local Rac inhibition process that destabilizes the leading edge to promote exploration. We show that this local inhibition enables cells to process input signal dynamics, linking front stability and orientation to local temporal increases in input signals.
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Newell-Litwa, Karen A., Mathilde Badoual, Hannelore Asmussen, Heather Patel, Leanna Whitmore, and Alan Rick Horwitz. "ROCK1 and 2 differentially regulate actomyosin organization to drive cell and synaptic polarity." Journal of Cell Biology 210, no. 2 (July 13, 2015): 225–42. http://dx.doi.org/10.1083/jcb.201504046.

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RhoGTPases organize the actin cytoskeleton to generate diverse polarities, from front–back polarity in migrating cells to dendritic spine morphology in neurons. For example, RhoA through its effector kinase, RhoA kinase (ROCK), activates myosin II to form actomyosin filament bundles and large adhesions that locally inhibit and thereby polarize Rac1-driven actin polymerization to the protrusions of migratory fibroblasts and the head of dendritic spines. We have found that the two ROCK isoforms, ROCK1 and ROCK2, differentially regulate distinct molecular pathways downstream of RhoA, and their coordinated activities drive polarity in both cell migration and synapse formation. In particular, ROCK1 forms the stable actomyosin filament bundles that initiate front–back and dendritic spine polarity. In contrast, ROCK2 regulates contractile force and Rac1 activity at the leading edge of migratory cells and the spine head of neurons; it also specifically regulates cofilin-mediated actin remodeling that underlies the maturation of adhesions and the postsynaptic density of dendritic spines.
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Dissertations / Theses on the topic "Front polaire"

1

Oziel, Laurent. "Variabilité de la mer de Barents et son impact sur le phytoplancton." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066483/document.

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La mer de Barents possède un écosystème particulièrement riche. Elle est affectée par le changement climatique actuel, comme le reste de l'Arctique. L'effet le plus visible et le plus connu est la réduction spectaculaire de la banquise. On examine dans cette thèse les répercussions de ces changements sur l'hydrologie et le phytoplancton en mer de Barents. Pour cela, on s'appuie sur la création d'une base de données historiques comprenant les paramètres hydrologiques et bio-géochimiques. Un modèle 3D bio-géochimique spécifique à l'écosystème arctique est aussi utilisé quand les observations sont manquantes. Enfin, les données satellites fournissent des séries temporelles de concentration de glace, de Chlorophyle-a...La mer de Barents est caractérisée par un front polaire séparant les eaux atlantiques issues des mers Nordiques des eaux arctiques dont la position est connue à l'ouest de 35°E. Nous avons pu montrer que ce front se sépare en deux branches dans l'Est du bassin: le front du Nord et le front du Sud. Ces fronts enferment les eaux de la mer de Barents qui se forment en hiver. Un doublement du volume des eaux atlantiques (une " Atlantification " de la mer de Barents), a aussi été mise en évidence. Elle accompagne un déplacement des fronts Nord et Sud vers le Nord-est. Le volume des eaux de la mer de Barents reste inchangé.Ces changements, affectant l'hydrologie et la glace de Mer, ont un impact significatif sur le phytoplancton. Les deux efflorescences qui le caractérisent ont lieu plus au Nord et à l'Est. La biomasse totale annuelle a augmenté de 40% lors des deux dernières décennies. Ce travail montre que les conditions de glace de mer et la structure frontale sont les paramètres clefs dirigeant la variabilitéinter-annuelle du phytoplancton
The Barents Sea has a particularly rich ecosystem. This is an Arctic region subject to intense climate changes. The drastic decrease in sea ice cover is the most visible effect. What are the impacts of these climatic changes on the hydrology and phytoplankton? In order to answer these questions, this thesis relies on the creation of an extensive historical database of physical and bio-geochemical parameters. A 3D bio-geochemical model with an Arctic specific ecosystem is used when observations are lacking. At least, remote sensing data provides valuable time series of Ice concentration, Chlorophyll-a... The Polar Front, separating the Atlantic Water coming from the Nordic Sea from the Arctic Water, is the principal feature of the Barents Sea region. Its position is known west of 35°E, but we showed that the polar front splits into two branches in the East part of the Barents Sea: the "Southern Front" and the "Northern Front". They enclose the winter locally formed Barents Sea Water. An “Atlantification”, illustrating a doubling of the Atlantic Water volume, has been evidenced and goes along with a North-eastward shift of the fronts. These hydrological and sea ice changes have a significant impact on the phytoplankton development. The two blooms of the Barents Sea occur further North and East with a 40% total anual biomass increase for the last two decades. This study suggests that the winter sea ice conditions and the frontal structure are the key mechanisms driving the inter-annual phytoplankton variability
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Gendron-Badou, Aïcha. "Paléopositions du front polaire antarctique au cours du Pléistocène dans la région de Kerguelen (Océan Indien austral)." Paris, Muséum national d'histoire naturelle, 1996. http://www.theses.fr/1996MNHN0024.

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Le front polaire antarctique (FPp) est la discontinuité la plus représentative du système hydrologique associé au continent antarctique. Elle lui est associée une sédimentation contrastée: schématiquement, boue biosiliceuse à diatomées au sud et boue carbonatée riche en nannofossiles au Nord. Cette sédimentation est sous le contrôle de la distribution des masses d'eau de surface, froides au Sud du front et plus chaudes au Nord. Deux référentiels fixes ont été choisis sur le plateau de Kerguelen (Océan Indien austral) de part et d'autre de la position actuelle du front polaire (vers 50°s) pour tenter de reconstituer ses paléopositions au cours du Pléistocène. La caractérisation des masses d'eaux de surface est obtenue par l'estimation de leurs paléotempératures par l'étude statistique de la flore siliceuse, en appliquant la fonction de transfert basée sur le modèle actuel de distribution des diatomées australes. La contribution des diatomées et du plancton calcaire à la sédimentation est mesurée par l'analyse quantitative globale du sédiment par spectroscopie infrarouge. La conjugaison de ces approches micropaléontologique et physique permet d'obtenir des données numériques exprimées en fonction du temps, au moins pour la carotte MD 80 308 (45°32'S). En dépit d'un contrôle stratigraphique insuffisant, les résultats obtenus pour la carotte MD 86 711 montrent de larges fluctuations des teneurs en silice biogénique (essentiellement diatomitique) qui peuvent atteindre 80%, alors que les carbonates ne constituent qu'un fond continu (aux alentours de 40%): ce qui caractérise le domaine antarctique. En revanche, pour le référentiel prélevé en domaine subantarctique (MD 80 308), c'est la courbe des carbonates qui montre les fluctuations les plus importantes, en particulier après 420 000 ans. On observe une corrélation entre les flux des constituants biogéniques (siliceux et carbonatés) et les températures d'été estimées pour la carotte MD 80 308: aux périodes de réchauffement correspondent une prédominance du flux des carbonates, et aux périodes les plus froides sont associées des élévations du flux de silice biogénique. En comparant ces données avec la répartition actuelle des températures des eaux de surface, on montre que le FP est remonté à plusieurs reprises au cours du Pléistocène au moins jusqu'à la latitude de 45°30'S. Il s'y serait maintenu pendant une longue période allant d'environ 1,178 Ma jusqu'à 420 000 ans (limite des stades isotopiques 11/12), date à partir de laquelle on observe une période de réchauffement correspondant à son recul vers le sud. On observe une forte instabilité du front depuis 420 000 ans avec plusieurs oscillations entre sa position actuelle (vers 49°30'S) et la latitude de la carotte MD 80 308 (45°32). On montre ainsi, que le FP se serait déplacé d'au moins 4 degrés de latitude (environ 450 km) vers le Nord , non seulement au cours des dernières périodes glaciaires, mais également avant 420 000 ans
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Krug, Jean. "Intéractions calottes polaires/océan : modélisation des processus de vêlage au front des glaciers émissaires." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU033/document.

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La contribution des calottes polaires à l'augmentation du niveau marin est un sujet de préoccupation majeure. Dans le cadre du réchauffement climatique, la dynamique de leurs glaciers émissaires évolue et ceux-ci accélèrent leur décharge de glace vers l'océan. En tant qu'exutoires des calottes polaires et régulateurs de leur perte de masse, la prise en compte de leur fonctionnement dans les prévisions d'augmentation du niveau marin est capitale. Cependant, les processus qui régissent leur dynamique sont mal contraints et il convient alors de réduire les incertitudes qui y sont liées. Les rétroactions entre la dynamique du front et la dynamique du glacier en sont un exemple représentatif. Dans ce cadre, cette thèse se concentre sur la modélisation de la dynamique du front de vêlage, et vise à proposer une nouvelle approche physique des mécanismes aboutissant au vêlage d'iceberg. Le travail réalisé ici couple la mécanique de l'endommagement et la mécanique de la rupture. Il intègre ainsi la dégradation progressive des propriétés rhéologiques de la glace aboutissant à la formation d'un champ de crevasses et modélise ensuite la propagation des fractures caractéristiques de l'évènement de vêlage. Ce modèle nouvellement créé est contraint sur une géométrie 2D en ligne d'écoulement du glacier Helheim, au Groenland, dont on parvient à reproduire un comportement cohérent de la partie terminale. Les tests de sensibilité menés sur chacun des paramètres introduits dans le modèle contraignent l'importance de chacun d'eux. On évalue ensuite l'impact sur la dynamique du front de deux forçages naturels couramment observés dans les fjords groenlandais : la fonte de la partie immergée du front et l'impact mécanique d'un mélange de glace (mélange de glace de mer et d'icebergs). Les résultats suggèrent que si la fonte affecte légèrement la dynamique du front, le mélange de glace provoque une réponse saisonnière d'une amplitude similaire aux variations observées dans la réalité. En frottant contre les parois du fjord, il empêche le vêlage et favorise l'avancée du glacier. On montre également que la fonte ne modifie pas le bilan de masse du glacier, mais que l'effet du mélange de glace est plus marqué. Enfin, nos résultats suggèrent que lorsque le glacier présente une extension flottante, un forçage élevé peut modifier l'équilibre du glacier et affecter plus considérablement son bilan de masse pluriannuel
Polar ice-sheets discharge and subsequent sea level rise is a major concern. Warming climate affects the behaviour of tidewater outlets glaciers and increases their ice discharge. As they drain the ice flow toward the ocean, it is pivotal to incorporate their dynamics when modelling the ice-sheet response to global warming. However, tidewater glacier dynamics is still complicated to understand, as they are believed to involve many feedbacks. The one between calving margin dynamics and glacier general dynamics is fundamental. This PhD thesis focuses on modelling the calving front of outlet glaciers, in order to enhance the representation of physical processes occurring at their margin. To do so, we build up a new framework for calving based on damage mechanics and fracture mechanics. This allows us to represent the slow degradation of the ice rheological properties from a virgin state to the appearance of a crevasse field, as well as the rapid fracture propagation associated with calving events. Our model is then constrained within a 2D flow-line representation of Helheim Glacier, Greenland. We find some parameters sets for which the glacier behaviour is coherent with its past evolution. Sensitivity tests are carried out and they reveal the significance of each model parameter. This new calving law is then employed to study the impact of submarine frontal melting and ice mélange (heterogeneous mixture of sea-ice and icebergs) on glacier dynamics. These two forcings are usually suspected to be responsible for the seasonal variations of the calving margin. Our results show that both forcings impact the front dynamics. The melting, however, only slightly changes the front position, when the ice mélange can force the glacier front to displace up to a few kilometers. Additionally, if the melting at the front is not sufficient to affect the inter-annual mass balance, this is not obvious when forced by ice mélange. At last, our model highlights a feature which is specific to floating glaciers: for the strongest forcings, the glacier equilibrium may be modified, as well as its pluri-annual mass balance.STAR
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4

Oziel, Laurent. "Variabilité de la mer de Barents et son impact sur le phytoplancton." Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066483.pdf.

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La mer de Barents possède un écosystème particulièrement riche. Elle est affectée par le changement climatique actuel, comme le reste de l'Arctique. L'effet le plus visible et le plus connu est la réduction spectaculaire de la banquise. On examine dans cette thèse les répercussions de ces changements sur l'hydrologie et le phytoplancton en mer de Barents. Pour cela, on s'appuie sur la création d'une base de données historiques comprenant les paramètres hydrologiques et bio-géochimiques. Un modèle 3D bio-géochimique spécifique à l'écosystème arctique est aussi utilisé quand les observations sont manquantes. Enfin, les données satellites fournissent des séries temporelles de concentration de glace, de Chlorophyle-a...La mer de Barents est caractérisée par un front polaire séparant les eaux atlantiques issues des mers Nordiques des eaux arctiques dont la position est connue à l'ouest de 35°E. Nous avons pu montrer que ce front se sépare en deux branches dans l'Est du bassin: le front du Nord et le front du Sud. Ces fronts enferment les eaux de la mer de Barents qui se forment en hiver. Un doublement du volume des eaux atlantiques (une " Atlantification " de la mer de Barents), a aussi été mise en évidence. Elle accompagne un déplacement des fronts Nord et Sud vers le Nord-est. Le volume des eaux de la mer de Barents reste inchangé.Ces changements, affectant l'hydrologie et la glace de Mer, ont un impact significatif sur le phytoplancton. Les deux efflorescences qui le caractérisent ont lieu plus au Nord et à l'Est. La biomasse totale annuelle a augmenté de 40% lors des deux dernières décennies. Ce travail montre que les conditions de glace de mer et la structure frontale sont les paramètres clefs dirigeant la variabilitéinter-annuelle du phytoplancton
The Barents Sea has a particularly rich ecosystem. This is an Arctic region subject to intense climate changes. The drastic decrease in sea ice cover is the most visible effect. What are the impacts of these climatic changes on the hydrology and phytoplankton? In order to answer these questions, this thesis relies on the creation of an extensive historical database of physical and bio-geochemical parameters. A 3D bio-geochemical model with an Arctic specific ecosystem is used when observations are lacking. At least, remote sensing data provides valuable time series of Ice concentration, Chlorophyll-a... The Polar Front, separating the Atlantic Water coming from the Nordic Sea from the Arctic Water, is the principal feature of the Barents Sea region. Its position is known west of 35°E, but we showed that the polar front splits into two branches in the East part of the Barents Sea: the "Southern Front" and the "Northern Front". They enclose the winter locally formed Barents Sea Water. An “Atlantification”, illustrating a doubling of the Atlantic Water volume, has been evidenced and goes along with a North-eastward shift of the fronts. These hydrological and sea ice changes have a significant impact on the phytoplankton development. The two blooms of the Barents Sea occur further North and East with a 40% total anual biomass increase for the last two decades. This study suggests that the winter sea ice conditions and the frontal structure are the key mechanisms driving the inter-annual phytoplankton variability
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Barton, Benjamin I. "Climate change in the Barents Sea : ice-ocean interactions, water mass formation and variability." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0053.

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L’étendue hivernale de la banquise en mer de Barents n’a cessé de diminuer, et un certain nombre d’études suggèrent que cette diminution pourrait coïncider avec des hivers très froids en Europe et Asie. L’eau Atlantique (AW) transportée vers la mer de Barents, se réchauffe. En mer de Barents, l’AW se transforme en Barents Sea Water (BSW), plus froide et moins salée. Etudier cette dernière nous permet d’en savoir plus sur l’influence de la saisonnalité de la banquise Arctique sur la stratification et la circulation de l’océan.Tout d’abord, nous utilisons des observations satellites pour localiser le Front Polaire (PF) qui matérialise la limite entre la BSW et l’eau Arctique. Nous établissons que l’étendue de la banquise était indépendante du PF jusqu’au milieu des années 2000, jusqu’à ce que le réchauffement de l’AW commence à limiter l’extension de la banquise hivernale au sud du front. Ensuite, en combinant données satellites et in situ, nous montrons que l’on peut surveiller ‘à distance’ les propriétés de la BSW : les variations de la température de surface de l’océan sont ainsi corrélées à celles du contenu en chaleur de la mer de Barents qui, associées à celles de la hauteur stérique, permettent également d’estimer son contenu en eau douce.Pour finir, nous utilisons un modèle à haute résolution pour calculer les bilans de volume, transport et flux des masses d’eau. Le volume de la BSW atteint un minimum en 1990 et 2004 : l’étendue de glace de mer hivernale ayant fondue l’été suivant était alors conséquente, résultant notamment d’une masse d’AW plus froide. L’événement de 2004 a permis une entrée massive d’AW, de plus en plus chaude, dans la mer de Barents
Winter sea ice has declined in the Barents Sea and there is growing evidence that the low sea ice here coincides with cold, winter surface air temperature in Europe and Asia. Atlantic Water (AW) transported into the Barents Sea is warming and its temperature variability is correlated with variability in sea ice extent. As AW extends into the Barents Sea it is modified into a cooler, fresher water mass called BarentsSea Water (BSW). There are limited observations of BSW despite its importance in the Arctic Ocean system, leading to the question, how does the seasonal sea ice impact ocean stratification and mean flow?First, satellite observations are used to find the Polar Front, a water mass boundary between BSW and fresher Arctic Water to the north. The sea ice extent was found to be independent of the Polar Front until the mid-2000s when warming AW prevented the extension of winter sea ice south of the front.Second, by combining satellite and in situ data, it is shown that sea surface temperature can approximate heat content in the Barents Sea. Using heat content with satellite steric height, freshwater content can also be estimated, showing the potential for remote monitoring of BSW properties.Third, a high-resolution model is used to calculate the volume, transport and flux budgets within the AW and BSW domain south of the Polar Front. The model shows BSW volume minimum years in 1990 and2004. Both events were preceded by extensive winter sea ice and substantial summer sea ice melt, a result of preceding, cool AW. The event in 2004 was more extreme and allowed warming AW a greater volume in the Barents Sea
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Massardier-Galatà, Lauriane. "Succès de la reproduction de prédateurs en contexte de changements climatiques et de la dynamique océanique – Application aux « central place foragers » des zones australes, approche par la modélisation individu centrée." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4050/document.

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Les changements climatiques ont un impact certain sur les écosystèmes marins. Un déplacement vers le sud des principaux systèmes de front servant de sites de nourrissage pour de nombreuses espèces de prédateurs supérieurs est susceptible de se produire dans les zones subantarctiques. Les « central place foragers », tels que les pinnipèdes, sont susceptibles de faire face à une augmentation de la distance entre leurs lieux d'alimentation et leurs colonies d'élevage. Nous avons étudié l’impact des changements climatiques sur le succès d’élevage et la dynamique de population des otaries à fourrure (Arctocephalus gazella) des Îles Kerguelen par le biais du développement du modèle individu centré, MarCPFS (Marine Central Place Foragers Simulator) qui montre que la survie du couple femelle-jeune est particulièrement sensible à la répartition des proies (abondance et structure), à la capacité de mémorisation des meilleurs sites de nourrissages trouvés par la femelle pendant la période d'élevage, à la taille des femelles et à la distance qu'il faut parcourir pour trouver la ressource. Les résultats suggèrent qu’au cours des trois prochaines décennies un déplacement vers le sud supérieur à 2km an 1 pourrait compromettre la survie et la durabilité des populations. Un couplage avec un modèle de simulation de la dynamique océanique et de la ressource (SEAPODYM) a permis des projections jusqu’à la fin de ce siècle basées sur le scénarios RCP8.5 du GIEC (2014), confirmant les tendances mises à jour précédemment. Ces travaux montrent que les perspectives de maintien des populations sont pessimistes y compris en envisageant une adaptation de la taille des individus
Climate change has certain impact on the marine ecosystems. A southward shift in productive frontal systems serving as the main foraging sites for many top predator species is likely to occur in the Subantarctic areas. Central place foragers, as seabirds and pinnipeds, are thus likely to cope with an increase in the distance between foraging locations and their land-based breeding colonies. We studied the impact of climate change on the breeding success and population dynamics of Antarctic fur seals (Arctocephalus gazella) at Kerguelen Islands by means of an individual based model we developped, MarCPFS (Marine Central Place Foragers Simulator) which showed that the survival of the female-pup pair is particularly sensitive to the distribution of preys (abundance and structure), to the memorization abilities of the best resource sites found by the female during the rearing period, to the female size and to the foraging distance which it is necessary to cover at each trip. The results suggest that during the next three decades a southward shift greater than 2 km year-1 could compromise the survival and the sustainability of the populations. A coupling with a model of simulation of the oceanic dynamics and the resource (SEAPODYM) allowed projections till the end of this century based on scenarios RCP8.5 of the IPCC (2014), confirming the trends previously obtained. Globally, these works lead us to conclude with pessimistic perspectives about the sustainability of populations even when considering an evolution through time towards individuals of greater sizes
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Massardier-Galatà, Lauriane. "Succès de la reproduction de prédateurs en contexte de changements climatiques et de la dynamique océanique – Application aux « central place foragers » des zones australes, approche par la modélisation individu centrée." Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4050.

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Les changements climatiques ont un impact certain sur les écosystèmes marins. Un déplacement vers le sud des principaux systèmes de front servant de sites de nourrissage pour de nombreuses espèces de prédateurs supérieurs est susceptible de se produire dans les zones subantarctiques. Les « central place foragers », tels que les pinnipèdes, sont susceptibles de faire face à une augmentation de la distance entre leurs lieux d'alimentation et leurs colonies d'élevage. Nous avons étudié l’impact des changements climatiques sur le succès d’élevage et la dynamique de population des otaries à fourrure (Arctocephalus gazella) des Îles Kerguelen par le biais du développement du modèle individu centré, MarCPFS (Marine Central Place Foragers Simulator) qui montre que la survie du couple femelle-jeune est particulièrement sensible à la répartition des proies (abondance et structure), à la capacité de mémorisation des meilleurs sites de nourrissages trouvés par la femelle pendant la période d'élevage, à la taille des femelles et à la distance qu'il faut parcourir pour trouver la ressource. Les résultats suggèrent qu’au cours des trois prochaines décennies un déplacement vers le sud supérieur à 2km an 1 pourrait compromettre la survie et la durabilité des populations. Un couplage avec un modèle de simulation de la dynamique océanique et de la ressource (SEAPODYM) a permis des projections jusqu’à la fin de ce siècle basées sur le scénarios RCP8.5 du GIEC (2014), confirmant les tendances mises à jour précédemment. Ces travaux montrent que les perspectives de maintien des populations sont pessimistes y compris en envisageant une adaptation de la taille des individus
Climate change has certain impact on the marine ecosystems. A southward shift in productive frontal systems serving as the main foraging sites for many top predator species is likely to occur in the Subantarctic areas. Central place foragers, as seabirds and pinnipeds, are thus likely to cope with an increase in the distance between foraging locations and their land-based breeding colonies. We studied the impact of climate change on the breeding success and population dynamics of Antarctic fur seals (Arctocephalus gazella) at Kerguelen Islands by means of an individual based model we developped, MarCPFS (Marine Central Place Foragers Simulator) which showed that the survival of the female-pup pair is particularly sensitive to the distribution of preys (abundance and structure), to the memorization abilities of the best resource sites found by the female during the rearing period, to the female size and to the foraging distance which it is necessary to cover at each trip. The results suggest that during the next three decades a southward shift greater than 2 km year-1 could compromise the survival and the sustainability of the populations. A coupling with a model of simulation of the oceanic dynamics and the resource (SEAPODYM) allowed projections till the end of this century based on scenarios RCP8.5 of the IPCC (2014), confirming the trends previously obtained. Globally, these works lead us to conclude with pessimistic perspectives about the sustainability of populations even when considering an evolution through time towards individuals of greater sizes
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Donnadille, Jérôme. "Dynamique d'altitude dans un cas de cyclogenèse au Nord du courant-jet polaire pendant Fastex : étude diagnostique et numérique." Toulouse 3, 2000. http://www.theses.fr/2000TOU30164.

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Hepburn, Laura. "Hydrothermal sediment geochemistry south of the Antarctic Polar Front." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/384574/.

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This thesis uses a novel, combined mineralogical, geochemical (including stable S iso- topes), and microbiological approach to semi-quantitatively determine Scotia Sea sedi- ment formation processes. The factors that control the localisation of chemosynthetic, microbial consortia in metalliferous sediment beneath Southern Ocean vent fields is investigated along with the impact of hydrothermal venting on sediment composition. Circum-Antarctic ridges represent nearly 40 % of the Earth’s ∼58,000 km ridge crest, but remain severely understudied. In the austral summer of 2009–2010, the Royal Research Ship James Cook expedition JC42 explored the northernmost (E2) and southernmost (E9) bare-rock segments of the East Scotia Ridge, and the sedimented Kemp Caldera (a southern feature of the South Sandwich Arc), and collected >20 co-registered vent fluid, chimney sulfide and hydrothermally-influenced sediment samples using the ISIS remotely-operated vehicle. The hydrothermal materials from E9 and the Kemp Caldera are the focus of this thesis. E9 sediment composition is controlled by the simple mix- ing of >90 % local basalt that is affected by subduction-related and enriched mantle components, <10 % particulate plume fallout, which is dominated by an Fe-, Cu-, Zn-, Ba-, and Pb-rich, near-plume phase, and <1 % collapsed chimney material. The ma- jor, minor, trace, and rare earth element sediment content at E9 is largely determined by proximity to active venting. The thin sediment cover throughout E9, indicates an early stage of sediment formation and the recent onset of venting at this site. Kemp Caldera sediment components include 55–60 % phreatomagmatic shards of local basalt that were most likely deposited by a recent, volcanic event, 30–45 % crystalline elemental S derived from the magmatic disproportionation of SO2 (identified by a δ34S signature of +4.8 ‰ to +5.9 ‰), and 0–10 % buoyant plume particles (rich in P, K, Mn, Fe, and the rare earth elements). Biogeochemical Fe, Mn, and S cycling is investigated in two very different sediment systems of the Kemp Caldera: Toxic Castle and Tubeworm Field. Toxic Castle sediments are compiled from the episodic deposition of magmatic and hydrothermal components, while pore fluid composition is strongly influenced by diffuse, upwelling hydrothermal fluid. The original magmatic-hydrothermal signature is diagenetically altered in the solid phase Tubeworm Field sediments, likely initiated by dissimilatory sulfate reduction. Pore fluid Fe and Mn redox zonation in the surface sediments at Tubeworm Field is typical of biogeochemical cycling in stratified marine sediments. Microbial cell counts (identified by 4’,6-diamidino-2-phenylindole staining and fluorescent in situ hybridisation microscopy) are relatively consistent across the ma- jor Tubeworm Field redox boundaries, although there is a significant downcore shift in the microbial community structure. A dominant presence of δ-, E-, and γ-proteobacteria (which host known S metabolisers), confirms active, microbial S cycling in the deeper Tubeworm Field sediments. Sediment descriptions from modern hydrothermal (partic- ularly back-arc basin-associated) systems are relatively scarce, in comparison to those of vent fluid and chimney material, which is surprising given the potential economic im- portance of hydrothermally-derived, metalliferous, rare earth-enriched sediments. This thesis increases our knowledge of sediment formation processes and subsequent biogeo- chemical cycling, in a range of back-arc-associated bare-rock and sedimented systems, along poorly-surveyed circum-Antarctic ridges, and accentuates the requirement for continued, interdisciplinary hydrothermal surveys of the global, submarine ridge system. We must fully understand the complex interaction of geological, chemical, and biologi- cal components that constitute the complete hydrothermal system, before we allow the commercial exploitation of unique ecosystems that have forever changed our perception of life in the deep sea.
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Garabato, Alberto Carlos Naveira. "On the physical controls of the biological uptake of CO←2 in the Antarctic circumpolar current." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367259.

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Books on the topic "Front polaire"

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Paquette, Robert G. The East Greenland Polar Front in autumn. Monterey, Calif: Naval Postgraduate School, 1985.

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F, Twitchell Paul, Rasmussen Erik A, Davidson Kenneth L, and International Conference on Polar/Arctic Lows (4th : 1988 : Madison, Wis.), eds. Polar and Arctic lows. Hampton, Va., USA: A. Deepak Pub., 1989.

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Lasky, Kathryn. The den of forever frost. New York, NY: Scholastic, Incorporated, 2018.

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Institution, Woods Hole Oceanographic, ed. Collection and processing of shipboard ADCP velocities from the Barents Sea Polar Front Experiment. Woods Hole, Mass: Woods Hole Oceanographic Institution, 1995.

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1987), Expedition Arktis (4th. Data report of RV "Polarstern" Cruise ARK IV/1, 1987 to the Arctic and Polar fronts. Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 1987.

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U, S. FROST Workshop (1993 Byrd Polar Research Center Ohio State University). U.S. FROST: Data and science plan : report from the U.S. FROST Workshop, August 2-3, 1993, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio, U.S.A. Columbus, Ohio: Byrd Polar Research Center, 1993.

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U.S. FROST Workshop (1993 Byrd Polar Research Center, Ohio State University). U.S. FROST: Data and science plan : report from the U.S. FROST Workshop, August 2-3, 1993, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio, U.S.A. Columbus, Ohio: Byrd Polar Research Center, 1993.

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Delaforce, Patrick. The Polar Bears: From Normandy to the relief of Holland with the 49th Division. Phoenix Mill, U.K: A. Sutton Pub., 1995.

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Delaforce, Patrick. The Polar Bears: Monty's left flank : from Normandy to the relief of Holland with the 49th Division. Stroud, Gloucestershire: Sutton Pub., 2003.

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Pierce, Stephen D. Acoustic doppler current profiler observations during the JGOFS AESOPS Antarctic polar front surveys I and II: R/V Revelle cruises from 20-Oct to 23-Nov 1997 and 9-Jan to 7-Feb 1998. Corvallis, Or: College of Oceanic & Atmospheric Sciences, Oregon State University, 1999.

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Book chapters on the topic "Front polaire"

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Moissoglu, Konstadinos, Stephen J. Lockett, and Stavroula Mili. "Visualizing and Quantifying mRNA Localization at the Invasive Front of 3D Cancer Spheroids." In Cell Migration in Three Dimensions, 263–80. New York, NY: Springer US, 2023. http://dx.doi.org/10.1007/978-1-0716-2887-4_16.

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AbstractLocalization of mRNAs at the front of migrating cells is a widely used mechanism that functionally supports efficient cell movement. It is observed in single cells on two-dimensional surfaces, as well as in multicellular three-dimensional (3D) structures and in tissue in vivo. 3D multicellular cultures can reveal how the topology of the extracellular matrix and cell-cell contacts influence subcellular mRNA distributions. Here we describe a method for mRNA imaging in an inducible system of collective cancer cell invasion. MDA-MB-231 cancer cell spheroids are embedded in Matrigel, induced to invade, and processed to image mRNAs with single-molecule sensitivity. An analysis algorithm is used to quantify and compare mRNA distributions at the front of invasive leader cells. The approach can be easily adapted and applied to analyze RNA distributions in additional settings where cells polarize along a linear axis.
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Friedman, Robert Marc. "Constituting the Polar Front, 1919–1920." In The Life Cycles of Extratropical Cyclones, 29–39. Boston, MA: American Meteorological Society, 1999. http://dx.doi.org/10.1007/978-1-935704-09-6_4.

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Eargle, John M. "Front-Back Ratio Versus Polar Pattern." In Electroacoustical Reference Data, 160–61. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2027-6_78.

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Eargle, John M. "Front-to-Total Ratio as a Function of Polar Pattern." In Electroacoustical Reference Data, 158–59. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2027-6_77.

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Westall, F., and J. Fenner. "Polar front Fluctuations and the Upper Gauss to Brunhes Paleooceanographic Record in the Southeast Atlantic Ocean." In Geological History of the Polar Oceans: Arctic versus Antarctic, 761–82. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2029-3_38.

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Domning, Daryl P. "The Terrestrial Posture of Desmostylians." In Smithsonian Contributions to Paleobiology, 99–111. Washington, D.C.: Smithsonian Institution Press, 2002. http://dx.doi.org/10.5479/si.00810266.93.99.

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An attempt to reconstruct a skeleton of <i>Paleoparadoxia </i>Reinhart, 1959 (Mammalia, Desmostylia), suggests that desmostylian terrestrial posture deviated from that of typical ungulates much less than has been supposed by other authors. Desmostylians probably had a quadrupedal stance, with the body welt off the ground and the limbs more or less under the body; a strongly arched spine and steeply inclined pelvis; slightly abducted elbows and more strongly abducted knees; and a digitigrade foot posture with an extended but not hyperextended wrist and hyperextended toes, the front toes pointing anterolaterad and the hind toes pointing forward. Most peculiarities of the skeleton have parallels in certain large, slow-moving terrestrial mammals, such as ground sloths and chalicotheres. The desmostylian skeleton was apparently well suited to supporting the body’s weight on the hindquarters, perhaps while the animal clambered slowly over very uneven ground. This most likely occurred while it foraged for marine algae or sea grasses in rocky intertidal areas of the North Pacific shoreline, and while it crossed these areas en route to and from the water. Locomotion in the water probably resembled that of polar bears, with alternate pectoral paddling as the principal means of propulsion and the hind limbs used for steering. Surprisingly, desmostylian-like features of the tibia and ankle also are found in many other primitive ungulates and deserve closer study.
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Van Der Loeff, Michiel M. Rutgers. "The Interaction between Hydrography and the Scavenging of 230Th and 231Pa Around the Polar Front, Antarctica." In Radionuclides in the Study of Marine Processes, 129. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3686-0_13.

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"Front Matter." In Polaris, i—viii. University of Calgary Press, 2016. http://dx.doi.org/10.1515/9781552388778-fm.

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"Front Matter." In Gestion de projet et expéditions polaires, I—VI. Presses de l'Université du Québec, 2011. http://dx.doi.org/10.2307/j.ctv18ph3ht.1.

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"Front Matter." In Gestion de projet et expéditions polaires, III—VI. Presses de l'Université du Québec, 2011. http://dx.doi.org/10.1515/9782760526839-fm.

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Conference papers on the topic "Front polaire"

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Pakkan, Meric, David Heng, and Ove Tobias Gudmestad. "Polar Lows and Their Implications on Marine Operations: Survivability Criteria." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10140.

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The oil resource potential in the Arctic/sub-Arctic regions is estimated to be as high as that 25% of the world’s yet-to-be-found. Nevertheless, operating in above-mentioned regions is more complicated and expensive than the ones in the North Sea. One of the most important aspects to consider in operating in these Arctic regions is the presence of polar lows and arctic fronts and storms. These extreme events and implications of them on the marine operations were the main focus of this study. While the maximum polar low-sourced wind speeds for 10-, 20- and 100-year return periods are estimated to be 55.37, 60.93 and 73.52 knots, the maximum polar low-sourced wave heights for 10-, 20- and 100-year return periods are calculated as 5.71, 6.66 and 8.82 meters, respectively. It is found out that polar lows weather conditions do not normally represent design values (survival conditions); however, they represent operational limitations. • We conclude that operations lasting longer than 72 hours shall be designed for a rougher weather than the polar lows lead to (survival mode). • For operations of duration less than 72 hours, the weather forecast is crucial and it must also be possible to abort the operation within a short period if one is close to a polar weather front as a polar low may appear very quickly.
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Cabral, P. M., L. Cabria, J. A. Garcia, and J. C. Pedro. "Polar transmitter architecture used in a Software Defined Radio context." In 2010 IEEE International Microwave Workshop Series on "RF Front-ends for Software Defined and Cognitive Radio Solutions" (IMWS). IEEE, 2010. http://dx.doi.org/10.1109/imws.2010.5440965.

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"POLAR Front-End Electronics: Concept, performance and qualification tests." In 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC). IEEE, 2013. http://dx.doi.org/10.1109/nssmic.2013.6829446.

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Real, Gaultier, Léo Buatois, G. Bazile Kinda, Lucie Bordois, Dag Tollefsen, Paul van Walree, and Pierre-Marie Poulain. "NARVAL2019: Ocean Acoustic Measurements in the Barents Sea Polar Front." In 6th Underwater Acoustics Conference and Exhibition. ASA, 2021. http://dx.doi.org/10.1121/2.0001486.

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Ran Ren, Taotao Yan, Peichen Jiang, Hao Hu, and Jianjun Zhou. "A 1.8V CMOS polar transmitter front-end for 900MHz EDGE system." In 2009 IEEE 8th International Conference on ASIC (ASICON). IEEE, 2009. http://dx.doi.org/10.1109/asicon.2009.5351410.

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Li, Ai-jun, and Yong Liu. "Water Wave Diffraction and Radiation by a Submerged Horizontal Circular Cylinder in Front a Vertical Wall." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18438.

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Abstract This article studies water wave diffraction and radiation by a submerged horizontal circular cylinder in front of a vertical wall under the assumption of linear potential flow theory. Based on the image principle, the hydrodynamic problem of a horizontal cylinder in front of a vertical wall is transformed into an equivalent problem involving symmetrical cylinders in a horizontally unbounded fluid domain. Then, analytical solutions for the present physical problem are developed using the method of multipole expansions combined with the shift of polar coordinate systems. The wave exciting forces on the cylinder as well as the added mass and radiation damping due to the cylinder oscillation are calculated. The analytical solutions converge very rapidly with the increasing truncated number of multipoles. Calculation examples are presented to examine the effects of different parameters on the hydrodynamic quantities of the cylinder. Results indicate that the hydrodynamic quantities of the cylinder in front of a vertical wall greatly differ from those in a horizontally unbounded fluid domain.
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Danner, Florian, and Christofer Kendall-Torry. "Effect of Blade Tip Modifications for Unducted Propulsors on Tip Vortex-Rotor Interaction Noise." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-27134.

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Front rotor tip vortices impinging on a downstream blade row of an unducted propulsor induce distinct unsteadiness to blade loads with associated sound emissions. Since the region of unsteadiness is concentrated near the blade tips, reducing the rear rotor tip diameter represents a potential means for minimising interaction noise. A survey on the aeroacoustic effects resulting from a cropped rear rotor in combination with a front rotor blade tip modification is therefore presented. Analyses are based on data from computational fluid dynamics solutions with the Reynolds-averaged Navier-Stokes equations and direct acoustic predictions. The evaluation of polar directivities, blade surface pressure disturbances and details of the unsteady flow field provide insight into the underlying phenomena. Results show that an arbitrary reduction of the rear rotor tip diameter does not necessarily decrease noise radiation and that winglet-like structures applied to the front rotor blade tips are capable of reducing acoustic emissions due to tip vortex-rotor interactions.
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Hernandez, Carlos Cilla, Viktor Krozer, Jens Vidkjaer, and Jorgen Dall. "POLARIS: ESA's airborne ice sounding radar front-end design, performance assessment and first results." In 2009 IEEE MTT-S International Microwave Symposium Digest (MTT). IEEE, 2009. http://dx.doi.org/10.1109/mwsym.2009.5165716.

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Chen, Y. N., U. Seidel, J. Chen, U. Haupt, and M. Rautenberg. "Experimental Investigation of the Flow Field of Deep Rotating Stall in a Centrifugal Compressor." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-160.

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The pressure field of deep rotating stall of a centrifugal compressor with two stall cells is analysed by means of the two-dimensional pressure pattern in the impeller determined by Chen et al. (1993). These authors transferred the pressure pattern measured on the shroud surface (i.e. in the absolute frame) to that related to the rotating blade channels. The transferred pressure pattern is thus a two-dimensional one. The existence of the low and high pressure vortices according to the Rossby wave theory is confirmed by this experiment. The development stages of the two vortices, in combination with the Rossby wave that steers the rotating stall, can be evaluated very well. The vortex low is developed from the front between the reverse flow (with high temperature and entropy) and the forward flow (with low temperature and entropy) due to baroclinic instability. Its center is situated within the channel of the splitter blade. This front is accompanied by a squall line of small-scaled eddies. This is the same phenomenon as can be observed on the meteorological polar front. The vortex high is induced by the vortex low. Its embryo starts on the pressure surface. Its center is situated behind the inlet edge of the splitter blade. It can be further verified that the stall cell is caused by the backflows of the induction fields of the two vortices (low and high).
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Huang, Yanxiang, Chunshu Li, Khaled Khalaf, Andre Bourdoux, Julien Verschueren, Qixian Shi, Piet Wambacq, Sofie Polling, Wim Dehaene, and Liesbet Van der Perre. "A 28 nm CMOS 7.04 Gsps polar digital front-end processor for 60 GHz transmitter." In 2016 IEEE Asian Solid-State Circuits Conference (A-SSCC). IEEE, 2016. http://dx.doi.org/10.1109/asscc.2016.7844203.

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