1,607 research outputs found

    Temporal and spatial distribution and abundance of flathead sole (Hippoglossoides elassodon) eggs and larvae in the western Gulf of Alaska

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    Data from ichthyoplankton surveys conducted in 1972 and from 1977 to 1999 (no data were collected in 1980) by the Alaska Fisheries Science Center (NOAA, NMFS) in the western Gulf of Alaska were used to examine the timing of spawning, geographic distribution and abundance, and the vertical distribution of eggs and larvae of flathead sole (Hippoglossoides elassodon). In the western Gulf of Alaska, flathead sole spawning began in early April and peaked from early to mid-May on the continental shelf. It progressed in a southwesterly direction along the Alaska Peninsula where three main areas of flathead sole spawning were indentified: near the Kenai Peninsula, in Shelikof Strait, and between the Shumagin Islands and Unimak Island. Flathead sole eggs are pelagic, and their depth distribution may be a function of their developmental stage. Data from MOCNESS tows indicated that eggs sink near time of hatching and the larvae rise to the surface to feed. The geographic distribution of larvae followed a pattern similar to the distribution of eggs, only it shifted about one month later. Larval abundance peaked from early to mid-June in the southern portion of Shelikof Strait. Biological and environmental factors may help to retain flathead sole larvae on the continental shelf near their juvenile nursery areas

    Ketamine and remote hyperalgesia

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    One-particle and few-particle billiards

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    We study the dynamics of one-particle and few-particle billiard systems in containers of various shapes. In few-particle systems, the particles collide elastically both against the boundary and against each other. In the one-particle case, we investigate the formation and destruction of resonance islands in (generalized) mushroom billiards, which are a recently discovered class of Hamiltonian systems with mixed regular-chaotic dynamics. In the few-particle case, we compare the dynamics in container geometries whose counterpart one-particle billiards are integrable, chaotic, and mixed. One of our findings is that two-, three-, and four-particle billiards confined to containers with integrable one-particle counterparts inherit some integrals of motion and exhibit a regular partition of phase space into ergodic components of positive measure. Therefore, the shape of a container matters not only for noninteracting particles but also for interacting particles

    Split histidine kinases enable ultrasensitivity and bistability in two-component signaling networks

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    Bacteria sense and respond to their environment through signaling cascades generally referred to as two-component signaling networks. These networks comprise histidine kinases and their cognate response regulators. Histidine kinases have a number of biochemical activities: ATP binding, autophosphorylation, the ability to act as a phosphodonor for their response regulators, and in many cases the ability to catalyze the hydrolytic dephosphorylation of their response regulator. Here, we explore the functional role of β€œsplit kinases” where the ATP binding and phosphotransfer activities of a conventional histidine kinase are split onto two distinct proteins that form a complex. We find that this unusual configuration can enable ultrasensitivity and bistability in the signal-response relationship of the resulting system. These dynamics are displayed under a wide parameter range but only when specific biochemical requirements are met. We experimentally show that one of these requirements, namely segregation of the phosphatase activity predominantly onto the free form of one of the proteins making up the split kinase, is met in Rhodobacter sphaeroides. These findings indicate split kinases as a bacterial alternative for enabling ultrasensitivity and bistability in signaling networks. Genomic analyses reveal that up 1.7% of all identified histidine kinases have the potential to be split and bifunctional

    Swinburnian Atonement and the Doctrine of Penal Substitution

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    This paper is a philosophical defense of the doctrine of penal substitution. I begin with a delineation of Richard Swinburne’s satisfaction-type theory of the atonement, exposing a weakness of it which motivates a renewed look at the theory of penal substitution. In explicating a theory of penal substitution, I contend that: (i) the execution of retributive punishment is morally justified in certain cases of deliberate wrongdoing; (ii) deliberate human sin against God constitutes such a case; and (iii) the transfer of the retributive punishment due sinners to Christ is morally coherent. Whatever else might be said for and against such a conception of the doctrine of the atonement, the plausibility of the theory presented here should give us pause in the often hasty rejection of the doctrine of penal substitutio

    Becoming Honest: Why We Lie and What Can Be Done About It

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    Information Effects in Multi-Unit Dutch Auctions

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    We design a multi-unit descending-price (Dutch) auction mechanism that has applications for resource allocation and pricing problems. We address specific auction design choices by theoretically and experimentally determining optimal information disclosure along two dimensions. Bidders are either informed of the number of bidders in the auction, or know that it is one of two possible sizes; they also either know the number of units remaining for sale or are unaware of how many units have been taken by other bidders. We find that revealing group size decreases bids, and therefore revenue, if units remaining are not shown. When group size is unknown the price also falls if the number of units remaining is revealed. The most efficient and largest revenue outcome occurs when bidders are not provided information on either group size or units remaining. These laboratory results conform to some directional predictions from our theory, although overbidding is common

    In Vitro Maturation of a Humanized Shark VNAR Domain to Improve Its Biophysical Properties to Facilitate Clinical Development

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    Acknowledgments: The authors would like to acknowledge the funding support for this work from Scottish Enterprise [VNAR_001(2012)] and the Biotechnology and Biological Sciences Research Council (BB/K010905/1).Peer reviewedPublisher PD
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