10,535 research outputs found

    Polar Amplification Due to Enhanced Heat Flux Across the Halocline

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    Abstract Polar amplification is a widely discussed phenomenon, and a range of mechanisms have been proposed to contribute to it, many of which involve atmospheric and surface processes. However, substantial questions remain regarding the role of ocean heat transport. Previous studies have found that ocean heat transport into the Arctic increases under global warming, but the reasons behind this remain unresolved. Here, we investigate changes in oceanic heat fluxes and associated impacts on polar amplification using an idealized ocean‐sea ice‐climate model of the Northern Hemisphere. We show that beneath the sea ice, vertical temperature gradients across the halocline increase as the ocean warms, since the surface mixed layer temperatures in ice‐covered regions are fixed near the freezing point. These enhanced vertical temperature gradients drive enhanced horizontal heat transport into the polar region and can contribute substantially to polar amplification

    The hyaluronan-binding serine protease from human plasma cleaves HMW and LMW kininogen and releases bradykinin

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    The influence of the hyaluronanbinding protease (PHBSP), a plasma enzyme with FVII- and pro-urokinase-activating potency, on components of the contact phase (kallikrein/kinin) system was investigated. No activation or cleavage of the proenzymes involved in the contact phase system was observed. The procofactor high molecular weight kininogen (HK), however, was cleaved in vitro by PHBSP in the absence of any charged surface, releasing the activated cofactor and the vasoactive nonapeptide bradykinin. Glycosoaminoglycans strongly enhanced the reaction. The cleavage was comparable to that of plasma kallikrein, but clearly different from that of coagulation factor FXIa. Upon extended incubation with PHBSP, the light chain was further processed, partially removing about 60 amino acid residues from the Nterminus of domain D5 of the light chain. These cleavage site(s) were distinct from plasma kallikrein or FXIa cleavage sites. PHBSP and, more interestingly, also plasma kallikrein could cleave low molecular weight kininogen in vitro, indicating that domains D5(H) and D6(H) are no prerequisite for kininogen cleavage. PHBSP was also able to release bradykinin from HK in plasma where the pro-cofactor circulates predominantly in complex with plasma kallikrein or FXI. In conclusion, PHBSP represents a novel kininogen-cleaving and bradykinin-releasing enzyme in plasma that shares significant catalytic similarities with plasma kallikrein. Since they are structurally unrelated in their heavy chains (propeptide), their similar in vivo catalytic activities might be directed at distinct sites where PHBSP could induce processes that are related to the kallikrein/kinin system

    Qualitative Music

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    Qualitative research has provided a home for innovative approaches to collecting, analyzing, and representing data (Hesse - Biber & Leavy, 2006; Janesick, 2011; Ketelle, 2010). Reflexive journaling, photography and photo elicitation, poetry, video representations, dramatic enactments, visual presentations, and play - writing are but a few of the creative techniques embraced by qualitative researchers in search of ways to help their audiences move beyond reading and into experiencing the data (Collier, 2001; Deacon, 2006). These formats have opened doors to re - inventions of traditional thick, rich descriptions and provided living, intentional metaphors through which a reader can filter data via their own emotional, cognitive, spiritual, and scholarly lenses. Music, however, is one area that has been minimally used as an approach to mining and re/presenting data. This piece explores the use of music in a qualitative research project. My intention is to initiate a conversation on how music can capture both participant and researcher experiences in a way that naturally challenges words, thoughts, reactions, and assumption

    The U.S.A. Answers; a Guide to Understanding

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    Wildlife Road Mortality Patterns in South Texas and Survey Methodology Improvement

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    Mortalities of wildlife caused by collisions with vehicles along roads are increasing in prevalence, threatening the existence of various species and populations. A better understanding of how mortalities change in response to natural and anthropogenic variables and efficient methods of obtaining mortality data are essential to mitigating such mortalities. This thesis investigates several key elements to improving road mortality surveys in south Texas. First, it was found that road mortality survey counts did not change under a pandemic-related lockdown and that 2 mortality survey observers detect more mortalities than 1. Analysis of brown pelican groundings on Texas State Highway 48 showed increased groundings with higher wind speed, lower air temperature, and lower air pressure. A pelican mortality mitigation effort was determined to have succeeded and use of an extensive citizen science dataset was validated. Lastly, road mortality video survey methodology was improved using more advanced cameras and optimized camera positions

    Attractor Metadynamics in Adapting Neural Networks

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    Slow adaption processes, like synaptic and intrinsic plasticity, abound in the brain and shape the landscape for the neural dynamics occurring on substantially faster timescales. At any given time the network is characterized by a set of internal parameters, which are adapting continuously, albeit slowly. This set of parameters defines the number and the location of the respective adiabatic attractors. The slow evolution of network parameters hence induces an evolving attractor landscape, a process which we term attractor metadynamics. We study the nature of the metadynamics of the attractor landscape for several continuous-time autonomous model networks. We find both first- and second-order changes in the location of adiabatic attractors and argue that the study of the continuously evolving attractor landscape constitutes a powerful tool for understanding the overall development of the neural dynamics

    Negative Friction and Lateral Loading on Piles

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    An example is first given of a structure founded on piles and having suffered damages caused by negative friction and passive lateral loading on the supporting piles. It appears that the effects of negative friction are in general less disastrous than should be expected from a simplified theoretical approach. The described case shows that, at the contrary, the passive lateral loadings, when not accounted for, become rapidly detrimental. Both influences are time delayed, with the consequence that the critical situation does mostly not occur during construction, but a certain time after completion. The design of a second structure, in which the passive lateral loading and negative friction on the piles were taken into account, and whose construction was successful, illustrated that the passive lateral loading is usually a much more determining factor than the negative friction and even every now and then than the dead and live loads

    Numerical solution and spectrum of boundary-domain integral equation for the Neumann BVP with variable coefficient

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 Taylor & Francis.In this paper, a numerical implementation of a direct united boundary-domain integral equation (BDIE) related to the Neumann boundary value problem for a scalar elliptic partial differential equation with a variable coefficient is discussed. The BDIE is reduced to a uniquely solvable one by adding an appropriate perturbation operator. The mesh-based discretization of the BDIEs with quadrilateral domain elements leads to a system of linear algebraic equations (discretized BDIE). Then, the system is solved by LU decomposition and Neumann iterations. Convergence of the iterative method is discussed in relation to the distribution of eigenvalues of the corresponding discrete operators calculated numerically.The work was supported by the grant EP/H020497/1 "Mathematical analysis of localised boundary-domain integral equations for BVPs with variable coefficients" of the EPSRC, UK
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