570 research outputs found

    Priming and Conservation Between Spatial and Cognitive Search

    Get PDF
    Abstract There is compelling molecular and behavioral evidence that human goal-directed cognition is an evolutionary descendent of animal foraging behavior. A key observation is that similar dopaminergic processes are used to modulate between exploratory and exploitative foraging behaviors and control attention across animal species. Moreover, defects in these processes lead to predictable goal-directed cognitive pathologies in humans, such as attention-deficit/hyperactivity disorder and Parkinson's disease. However, the cognitive relationships between exploration in space and exploration in the mind have not been examined. Using a spatial foraging task with two treatment conditions (clumpy and diffuse), followed by a word search task involving patches of words to be found in letter sets, we show that individuals who experienced clumpy resource distributions in space behave as if resources are more densely clumped in the word search task, relative to those who experienced the diffuse spatial treatment. We show this is not a function of general arousal but is consistent with longer givingup times in the word search task, which is a qualitative prediction of optimal foraging theory. We also show that behavioral tendencies during search are conserved within individuals: Those who explore more of the physical space leave letter sets sooner. Along with the biological evidence, our results support a general search process underlying cognition, which operates both in external and internal environments

    Seismic Signature of a Swan Hills (Frasnian) Reef Reservoir, Snipe Lake, Alberta

    Get PDF
    Swan Hills formation (Frasnian stage) carbonate buildups of the Beaverhill Lake group are generally of low relief and considerable areal extent and are overlain by and encased within the relatively high-velocity shale of the Waterways formation, which thins but does not drape across the reefs. Consistent with this picture, prereef seismic events are not significantly pulled up beneath the reefs nor are postreef events draped across them. Indeed, the seismic images of these reefs are effectively masked by the high-amplitude reflections from the overlying top of the Beaverhill Lake group and underlying Gilwood member and cannot be distinguished from those of the basin fill. However, it is possible to identify the reefs indirectly on conventionally processed seismic sections because the image of the encompassing Beaverhill Lake/Gilwood interval varies significantly from onreef to offreef positions.One such Swan Hills formation field at Snipe Lake has an areal extent of about 90 km2 and typical reef relief of some 50 m above the platform facies. This reef is shown to be recognizable on three example seismic lines from interference phenomena that vary laterally in association with the lateral variations in thickness of the Swan Hills formation. These phenomena include an offreef peak that is one half-cycle below the Beaverhill Lake reflection trough and that dies out laterally going onreef, a tendency for the amplitude of the Gilwood event to decrease beneath the reef, and thinning of the order of 5 ms of the onreef section relative to the offreef section. Through seismic modeling, these seismic-image characteristics are seen to be predictable geophysical manifestations of the inherent geologic variations

    Alternative approaches to the legal, institutional and financial aspects of developing an inter-island electrical transmission cable system

    Get PDF
    This study (I) delineates three comprehensive alternative scenarios for the development, financing, construction, ownership, regulation and operation of an inter-island electric energy transmission cable systemDepartment of Planning and Economic Development, State of Hawai

    The PDK1 master kinase is over-expressed in acute myeloid leukemia and promotes PKC-mediated survival of leukemic blasts

    Get PDF
    PDK1 is a master kinase that activates at least six protein kinase groups including AKT, PKC and S6K and is a potential target in the treatment of a range of malignancies. Here we show overexpression of PDK1 in over 40% of myelomonocytic acute leukemia patients. Overexpression of PDK1 occurred uniformly throughout the leukemic population, including putative leukemia-initiating cells. Clinical outcome analysis revealed PDK1 overexpression was associated with poorer treatment outcome. Primary acute myeloid leukemia blasts over-expressing PDK1 showed improved in vitro survival and ectopic expression of PDK1 promoted the survival of myeloid cell lines. Analysis of PDK1 target kinases revealed that PDK1 overexpression was most closely associated with increased phosphorylation of PKC isoenzymes and inhibition of PKC strongly inhibited the survival advantage of PDK1 over-expressing cells. Membrane localization studies implicated PKCα as a major target for PDK1 in this disease. PDK1 over-expressing blasts showed differential sensitivity to PDK1 inhibition (in the low micromolar range) suggesting oncogene addiction, whilst normal bone marrow progenitors were refractory to PDK1 inhibition at effective inhibitor concentrations. PDK1 inhibition also targeted subpopulations of leukemic blasts with a putative leukemia-initiating cell phenotype. Together these data show that overexpression of PDK1 is common in acute myelomonocytic leukemia and is associated with poorer treatment outcome, probably arising from the cytoprotective function of PDK1. We also show that therapeutic targeting of PDK1 has the potential to be both an effective and selective treatment for these patients, and is also compatible with current treatment regimes

    Annealing of irradiated n+p InP buried homojunctions

    Get PDF
    At the last SPRAT conference, the Naval Research Laboratory (NRL) presented results from two experiments. One studied n+p diffused junction (DJ) InP solar cells, and the other studied n+p shallow homojunction (SHJ) InP mesa diodes grown by metalorganic chemical vapor deposition (MOCVD). The former work showed that a DJ solar cell in which the maximum power P(sub max) had been degraded by nearly 80 percent under irradiation recovered completely under short circuit illumination at 450K. The recovery was accompanied by the removal of all but one of the radiation-induced defect levels. The latter work, on the other hand, showed that the radiation-induced defects in the SHJ diodes did not anneal until the temperature reached 650K. These results suggest that an irradiated DJ solar cell, under illumination, will anneal at a temperature 200K lower than an irradiated SHJ cell. This is an unexpected result considering the similarity of the devices. The goal of the present research is to explain this different behavior. This paper investigates two points which arose from the previous studies. The first point is that the DJ cells were annealed under illumination while the SHJ diodes were annealed without bias. The second point investigated here is that the emitters of the DJ and SHJ devices were significantly different

    Prostanoid receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

    Get PDF
    Prostanoid receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Prostanoid Receptors [644]) are activated by the endogenous ligands prostaglandins PGD2, PGE1, PGE2 , PGF2α, PGH2, prostacyclin [PGI2] and thromboxane A2. Measurement of the potency of PGI2 and thromboxane A2 is hampered by their instability in physiological salt solution; they are often replaced by cicaprost and U46619, respectively, in receptor characterization studies

    Prostanoid receptors (version 2020.4) in the IUPHAR/BPS Guide to Pharmacology Database

    Get PDF
    Prostanoid receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Prostanoid Receptors [661]) are activated by the endogenous ligands prostaglandins PGD2, PGE1, PGE2 , PGF2α, PGH2, prostacyclin [PGI2] and thromboxane A2. Differences and similarities between human and rodent prostanoid receptor orthologues, and their specific roles in pathophysiologic conditions are reviewed in [423]. Measurement of the potency of PGI2 and thromboxane A2 is hampered by their instability in physiological salt solution; they are often replaced by cicaprost and U46619, respectively, in receptor characterization studies
    corecore