In this paper, we investigate global dynamics for a system of delay differential equations which describes a virus-immune interaction in vivo. The model has two distributed time delays describing time needed for infection of cell and virus replication. Our model admits three possible equilibria, an uninfected equilibrium and infected equilibrium with or without immune response depending on the ...

We present a novel approach to the nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) analysis of complex samples with a non-trivial distribution of longitudinal relaxation rates R1. The method, denominated PERFIDI, aims at separating signals arising from components with different R1's prior to actual data acquisition. Given any standard NMR / MRI pulse sequence, by itself in...

Different Drosophila photoreceptors (R cells) connect to neurons in different optic lobe layers. R1-R6 axons project to the lamina; R7 and R8 axons project to separate layers of the medulla. We show a receptor tyrosine phosphatase, PTP69D, is required for lamina target specificity. In Ptp69D mutants, R1-R6 project through the lamina, terminating in the medulla. Genetic mosaics, transgene rescue...

The class I E. coli ribonucleotide reductase, composed of homodimers of R1 and R2, catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. The reduction process involves the tyrosyl radical on R2 that generates a transient thiyl radical on R1 over a proposed distance of 35 A. A mechanism-based inhibitor, 2'-azido-2'-deoxyuridine-5'-diphosphate, that reduces the tyro...

ILIAS ANDRIKOPOULOS, AVRAAM POULIAKIS, AND IOANNIS MERTZANIS, SPACE HELLAS MERKOURIS KARALIOPOULOS, KANAGASABAPTHY NARENTHIRAN, AND BARRY EVANS, UNIVERSITY OF SURREY THIBAULT GALLET, MICHEL DURAND, AND MICHEL MAZZELLA, ALCATEL SPACE JURGEN VANDERMOT AND MICHAEL DIEUDONNÉ, AGILENT TECHNOLOGIES LAURENT ROULLET, UDCAST; ERIC BOURDIN, ERCOM; MICHAEL WOLF, DAIMLERCHRYSLER DEMONSTRATION WITH FIELD TR...

AN RFID BASED UBIQUITOUS FRAMEWORK FOR MOBILE OBJECT TRACKING

Workflows are characterized by multiple aspects: the functional aspect describes what has to be executed; the behavioral aspect tells when to execute a workflow; the organizational aspect determines agents that have to perform a workflow; the informational aspect defines data flow between workflows. In this paper we present a workflow model which follows this separation into various aspects. Th...

European vowels are mainly distinguished by the two lowest resonance frequencies (R1 and R2) of the vocal tract. Once the pitch frequency f(0) exceeds the value of R1 in normal speech, sopranos can deliberately "tune" R1 to match f(0). This increases loudness, uniformity of tone, and ease of singing, at some cost to intelligibility. Resonance tuning would be assisted if the pitch of the note wr...

(1) Let F , F1, F2 be finite sequences of elements of R and given r1, r2. If F1 = 〈r1〉 F or F1 = F a 〈r1〉 and if F2 = 〈r2〉 F or F2 = F a 〈r2〉, then ∑(F1−F2) = r1− r2. (2) Let F1, F2 be finite sequences of elements of R. If lenF1 = lenF2, then len(F1 +F2) = lenF1 and len(F1−F2) = lenF1 and ∑(F1 +F2) = ∑F1 +∑F2 and ∑(F1−F2) = ∑F1−∑F2. (3) Let F1, F2 be finite sequences of elements of R. If lenF1 ...

The neurotransmitter gamma-aminobutyric acid (GABA) mediates inhibitory signaling in the brain via stimulation of both GABA(A) receptors (GABA(A)R), which are chloride-permeant ion channels, and GABA(B) receptors (GABA(B)R), which signal through coupling to G proteins. Here we report physical interactions between these two different classes of GABA receptor. Association of the GABA(B) receptor ...