413 research outputs found
ELECTRONIC COMMERCE SECURITY IN THE CONTEXT OF THE MEANS OF PAYMENT DEMATERIALIZATION
No full textSome items regarding electronic commerce, electronic vulnerabilities, electronic means of payment, digital money and electronic micropayments are presented below. Then is presented a method of assessing the quality of applications and e-commerce Web sites. This method is then adapted from the operational point of view, developed and implemented in the study of the electronic micropayment systems’ security, in the purpose of analyzing and evaluating their security in the context of the means of payment dematerialization.e-commerce, micropayment, security, encryption, digital economy, EWAM
A COMPARISON OF THE MOST POPULAR ELECTRONIC MICROPAYMENT SYSTEMS
No full textThe buying and selling of products or services over electronic systems such as the Internet and other computer networks is known as electronic commerce. In order to reduce the costs of electronic transactions, when one exchanges cheaper goods and services, specific payment protocols must be used. These protocols are actually the foundation for electronic micropayments, which implement simplified and cheaper schemes intended for small value transactions. In this paper we shall present and compare the main characteristics of the most popular micropayment systems used in both face-to-face and remote commerce.e-commerce, micropayment, security, encryption, Chipper, GeldKarte, Mondex, Proton, First Virtual, NetBill, KLELine, Odysseo, MicroMint
Dematerialized Monies – New Means of Payment
No full textIn this paper, we will outline the financial context in which the main means of payment dematerialization occurs. We will present the main characteristics of these new types of dematerialized monies: electronic money, virtual money, digital money, private money, purses and holders.means of payment, dematerialized monies: electronic, virtual, digital, private, purses and holders.
DEMATERIALIZED MONIES – NEW MEANS OF PAYMENT
No full textIn this paper, we will outline the financial context in which the main means of payment dematerialization occurs. We will present the main characteristics of these new types of dematerialized monies: electronic money, virtual money, digital money, private money, purses and holders.Means of payment, dematerialized monies: electronic, virtual, digital, private, purses and holders
"Christabel" and the politics of fragmentation
No full textThis thesis attempts to situate Coleridge's “Christabel” as a text that exists at the intersection of 19th century Queer discourse and post-structural theory. By looking at “Christabel” as both a queer text and a fragment poem, this thesis makes the case that one type of discourse informs the other and the fragmentary nature of the poem echoes and supports analysis of “Christabel” as a queer text. It relies on the work of prominent writers on Romantic Fragment Poems as well as Derridean post-structural discourse as a theoretical model to understand Christabel's relationship with Geraldine and the fragmentary nature of the poem that obfuscates their relationship.M.A.Includes bibliographical referencesby Calin Thomas Grajk
A Poet at the Fountain: Essays on the Narrative Verse of Guillaume de Machaut
No full textThis collection is the first full-length literary study on Machaut, France’s leading poet and musician of the 14th century. Machaut’s narrative poems, called dits, have only been lightly studied. Here, author William Calin examines the works for their intrinsic merit and for their historical importance in influencing many writers, most notably Chaucer.
William Calin is professor of Romance Languages at the University of Oregon.https://uknowledge.uky.edu/upk_french_and_francophone_literature/1002/thumbnail.jp
Introduction to Neuroscience - Neurophysiology
No full textThis is an early draft of a chapter from a new Introduction to Neuroscience textbook, an effort that is:
Open source, available free to students
Faculty created
Peer reviewed (in progress)
High quality, including professional illustrations and learning resources
This textbook is edited by
Elizabeth Kirby, PhD
Melissa J. Glenn, PhD
Noah J. Sandstrom, PhD and
Christina L. Williams, CL
and supported by funding from the National Science Foundation
This early preview of the book is posted by Bob Calin-Jageman, an author Chapter (2 on neurophysiology. The purpose of posting this early-stage chapter here is:
To make it available for Dr. Bob’s Introduction to Neuroscience students
To gather feedback from others interested in this chapter or project
If you have any feedback, find a typo, notice an inaccuracy, etc… please submit your comments to Bob Calin-Jageman via email or social media
Generalized two-field α-attractor models from geometrically finite hyperbolic surfaces
No full textWe consider four-dimensional gravity coupled to a non-linear sigma model whose scalar manifold is a non-compact geometrically finite surface Σ endowed with a Riemannian metric of constant negative curvature. When the space-time is an FLRW universe, such theories produce a very wide generalization of two-field α-attractor models, being parameterized by a positive constant α, by the choice of a finitely-generated surface group Γ⊂PSL(2,R) (which is isomorphic with the fundamental group of Σ) and by the choice of a scalar potential defined on Σ. The traditional two-field α-attractor models arise when Γ is the trivial group, in which case Σ is the Poincaré disk. We give a general prescription for the study of such models through uniformization in the so-called “non-elementary” case and discuss some of their qualitative features in the gradient flow approximation, which we relate to Morse theory. We also discuss some aspects of the SRST approximation in these models, showing that it is generally not well-suited for studying dynamics near cusp ends. When Σ is non-compact and the scalar potential is “well-behaved” at the ends, we show that, in the naive local one-field truncation, our generalized models have the same universal behavior as ordinary one-field α-attractors if inflation happens near any of the ends of Σ where the extended potential has a local maximum, for trajectories which are well approximated by non-canonically parameterized geodesics near the ends; we also discuss spiral trajectories near the ends. Generalized two field α-attractors illustrate interesting consequences of nonlinear sigma models whose scalar manifold is not simply connected. They provide a large class of tractable cosmological models with non-trivial topology of the scalar field space. © 2018 The Author(s)11Nsciescopu
Monitoring and controlling GABAergic interneuron subtypes during epileptiform activity
No full textInhibitory synaptic transmission is of paramount importance for maintaining the delicate balance between excitation and inhibition in the brain. If this balance is perturbed in favour of excitation, epilepsy is likely to develop. Fast synaptic inhibition is mediated by type A γ-aminobutyric acid ionotropic receptors (GABAARs), which are primarily permeable to Clâ. The strength of synaptic inhibition crucially depends on the release of GABA from different populations of presynaptic interneurons and the transmembrane electrochemical gradient for Clâ in postsynaptic cells. GABAAR-mediated inhibition has been shown to oppose epileptic seizures by establishing an inhibitory restraint against spreading excitation. Of the different subtypes of GABAergic interneurons, parvalbumin-expressing (PV) interneurons that target the somatic compartment of excitatory neurons have been strongly implicated in this process. In the context of an epileptic seizure, it is thought that the inhibitory restraint is overwhelmed by runaway excitation, and the seizure front is able to spread from the pathologic epileptic focus into adjacent healthy areas, referred to as the âpenumbraâ.
In the first part of this thesis I assess the potential of using chemogenetic strategies to suppress epileptiform activity by boosting the synaptic output from three major interneuron populations in the rodent hippocampus: PV, somatostatin (SST) and vasoactive intestinal peptide (VIP) expressing interneurons. Electrophysiological recordings in an in vitro model of epilepsy reveal that the interneuron populations exhibit different effects on epileptiform events. Recruiting VIP interneurons does not change the total duration of epileptiform activity. By contrast, recruiting SST or PV interneurons produces robust suppression of epileptiform synchronisation. PV interneurons exhibit the strongest effect per cell, eliciting at least a five-fold greater reduction in epileptiform activity than the other cell types. Consistent with this, I find that in vivo chemogenetic recruitment of PV interneurons suppresses convulsive behaviours by more than 80%.
In the second part of the thesis I use a genetically-encoded reporter to investigate activity-dependent intracellular pH and Clâ concentration transients in pyramidal neurons and PV, SST and VIP interneurons. I demonstrate that pyramidal neurons and interneurons have different pH and intracellular Clâ concentration steady states, and exhibit distinct dynamics during epileptiform events. Compared to the other cell types, PV interneurons maintain a relatively stable intracellular Clâ concentration, even when challenged with epileptiform activity. This suggests that PV interneurons may be more likely to maintain a balance in their excitatory and inhibitory synaptic inputs during seizures.
In the final part of the thesis I investigate the contribution of PV interneurons to inhibitory restraint in an in vitro model of the epileptic penumbra. Although PV interneurons are recruited in response to spreading excitation, they can be overwhelmed as they enter a state referred to as âdepolarising blockâ, which is characterized by a decrease in action potential firing. To investigate the impact of this process, I use a light-activated optogenetic tool to induce brief hyperpolarisations of the PV interneuron membrane potential. This successfully reduces depolarising block in PV interneurons, enhances their action potential firing, and reduces the spread of epileptiform activity.
In conclusion, this thesis demonstrates that selective enhancement of inhibitory synaptic pathways offers potential as an anti-seizure strategy, providing valuable insights into the development of therapeutic interventions.</p
Long non-coding RNAs and cancer: a new frontier of translational research?
No full textAuthor manuscriptTiling array and novel sequencing technologies have made available the transcription profile of the entire human genome. However, the extent of transcription and the function of genetic elements that occur outside of protein-coding genes, particularly those involved in disease, are still a matter of debate. In this review, we focus on long non-coding RNAs (lncRNAs) that are involved in cancer. We define lncRNAs and present a cancer-oriented list of lncRNAs, list some tools (for example, public databases) that classify lncRNAs or that scan genome spans of interest to find whether known lncRNAs reside there, and describe some of the functions of lncRNAs and the possible genetic mechanisms that underlie lncRNA expression changes in cancer, as well as current and potential future applications of lncRNA research in the treatment of cancer.RS is supported as a fellow of the TALENTS Programme (7th R&D Framework Programme, Specific Programme: PEOPLE—Marie Curie Actions—COFUND). MIA is supported as a PhD fellow of the FCT (Fundação para a Ciência e Tecnologia), Portugal. GAC is supported as a fellow by The University of Texas MD Anderson Cancer Center Research Trust, as a research scholar by The University of Texas System Regents, and by the Chronic Lymphocytic Leukemia Global Research Foundation. Work in GAC’s laboratory is supported in part by the NIH/ NCI (CA135444); a Department of Defense Breast Cancer Idea Award; Developmental Research Awards from the Breast Cancer, Ovarian Cancer, Brain Cancer, Multiple Myeloma and Leukemia Specialized Programs of Research Excellence (SPORE) grants from the National Institutes of Health; a 2009 Seena Magowitz–Pancreatic Cancer Action Network AACR Pilot Grant; the Laura and John Arnold Foundation and the RGK Foundation
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