The East Greenland Current North of Denmark Strait: Part II

Deals primarily with data from cruises of the Edisto, summers 1964-65, and 1965 drift of Arlis II; supported by the Office of Naval Research through the Arctic Institute of North America. Pt 2 gives more detailed data on the temperature/salinity distributions and movements of the polar water, which represents only a minor part of the total flow, but constitutes the upper layer of the East Greenland Current and mainly controls the ice distribution; the Atlantic intermediate water, the major component of the total transport, warmer than the other waters, whose westward movement from the West Spitsbergen current begins just north of 75 N, occurs over a wide range of latitude, probably to 80 N, with the depth of the layer decreasing westward. At about 73 N, warm water moves eastward in a cyclonic movement presumably associated with that of the polar water in the Jan Mayen Polar Current; warm water not involved in this movement continues southward near the continental slope at >200 m depths. The deep water (below 1500 m) underlying the Norwegian Sea gyre (S and SE of Jan Mayen) and Greenland Sea gyre (NE of Jan Mayen) can be differentiated by temperature, the one always warmer than -1C, the other always colder. The deep water along the Greenland slope is either the Norwegian Sea or the transitional type; that of the Polar basin comes primarily from the Norwegian Sea.Le courant de l'est du Groenland, au nord du Détroit de Danemark. Deuxième partie. Des mesures directes de courant et des études de distribution des températures dans la mer du Groenland indiquent que, si les eaux polaires du courant de l'Est du Groenland tirent leur origine de l'océan Arctique, la masse des eaux intermédiaires et profondes circule de façon cyclonique. Il y a des changements saisonniers systématiques dans la température et la salinité des eaux polaires. Ces changements sont liés au cycle annuel de formation et de fonte de la glace, et sont conditionnés par l'advection horizontale, la diffusion turbulente verticale et, en hiver, par la convection pénétrative. En été, il existe une tendance baroclinique prononcée qui devrait se manifester par une réduction de la vitesse du courant en fonction de la profondeur. Cependant, des mesures directes de courant au cours de l'hiver montrent que cette variation n'existe pas. La cause le plus probable de cette anomalie est que l'importance relative de la contribution baroclinique au gradient de pression varie selon la saison. On a observé à toutes les profondeurs du courant de l'Est du Groenland des déplacements latéraux des masses d'eau de 70 km ou plus en quelques jours, ce qui suggère comme cause première une perturbation barotropique à grande échelle

The East Greenland Current North of Denmark Strait: Part I

Deals primarily with data from cruises of the Edisto, summers 1964-65, and 1965 drift of Arlis II; supported by the Office of Naval Research through the Arctic Institute of North America. Pt 1 summarizes previously published papers on the East Greenland Current, notes some bathymetric features of the western Greenland Sea and its water masses, and discusses general features of the velocity field, mean velocities and volume transports of the current.Le courant du Groenland oriental au nord du détroit de Danemark. Au cours de l'hiver de 1965, des mesures effectuées dans le courant du Groenland oriental ont montré que sur le talus continental, la circulation comporte d'importantes composantes dirigées vers le rivage, ce qui représente probablement un flux vers l'ouest selon le mouvement d'Ekman. La vitesse ne diminue pas beaucoup avec la profondeur, ce qui indique que le mode barotropique domine la circulation. Les vitesses typiques du courant sont de 10 à 15 cm/s‾¹.Au cours de l'hiver, le débit du courant dépasse 35 x 10⁶ m³/s‾¹. Cet ordre de grandeur dépasse les anciennes estimations et, malgré les fluctuations saisonnières possibles, il semble que le courant du Groenland oriental correspond surtout à une circulation interne des mers du Groenland et de Norvège, plutôt qu'à un émissaire du bassin polaire central

The search rate of the African weaver ant in cashew

Oecophylla longinoda is a species of eusocial colony living ants that prey upon other insects to feed their larva. Many of these insects are considered pests. An ecosystem model of the interactions between an O. longinoda colony and its potential prey is under construction by the team behind this article, and it is unknown which functional response equations are useful for eusocial insect colonies. We investigated the search rate of O. longinoda using artificial feeding experiments in a Tanzanian cashew (Anacardium occidentale L.) orchard to determine the search efficiency of the ants, and to assess which functional response equation can be used for eusocial insects. Artificial feeding experiments consisted of providing each of ten colonies 50 pieces of sardine (175 mg dry weight in average) in cashew trees at time 0 and counting the remaining food items at four intervals of 45 minutes during a seven day period. The equations of Gutierrez-Baumgärtner, Lotka-Volterra, and Nicholson-Bailey were assessed and the Nicholson-Bailey equation was found to be most suitable. The Gutierrez-Baumgärtner equation is useful if the demand for storage can be assessed. A large variation in search rates was found between the observed colonies and this problem is discussed in relation to Oecophylla sp. efficacy as a biological control agent

Anomalous sea-ice reduction in the Eurasian Basin of the Arctic Ocean during summer 2010

Special Issue: The Second International Symposium on the Arctic Research (ISAR - 2

In utero exposure to a maternal high-fat diet alters the epigenetic histone code in a murine model

OBJECTIVE: Data from animal models show that in utero exposure to a maternal high-fat diet (HFD) renders susceptibility of these offspring to the adult onset of metabolic syndrome. We and others have previously shown that epigenetic modifications to histones may serve as a molecular memory of the in utero exposure, rendering the risk of adult disease. Because mice heterozygous for the Glut4 gene (insulin sensitive glucose transporter) born to wild-type (WT) mothers demonstrate exacterbated metabolic syndrome when exposed to an HFD in utero, we sought to analyze the genome-wide epigenetic changes that occur in the fetal liver in susceptible offspring. STUDY DESIGN: WT and Glut4(+/-) (G4(+/-)) offspring of WT mothers that were exposed either to a control or an HFD in utero were studied. Immunoblotting was used to measure hepatic histone modifications of fetal and 5-week animals. Chromatin immunoprecipitation (ChIP) followed by hybridization to chip arrays (ChIP-on-chip) was used to detect genome-wide changes of histone modifications with HFD exposure. RESULTS: We found that levels of hepatic H3K14ac and H3K9me3 significantly increased with HFD exposure in WT and G4(+/-) fetal and 5-week offspring. Pathway analysis of our ChIP-on-chip data revealed differential H3K14ac and H3K9me3 enrichment along pathways that regulate lipid metabolism, specifically in the promoter regions of Pparg, Ppara, Rxra, and Rora. CONCLUSION: We conclude that HFD exposure in utero is associated with functional alterations to fetal hepatic histone modifications in both WT and G4(+/-) offspring, some of which persist up to 5 weeks of age