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Search Results: 1 - 10 of 2520 matches for " Joan Farran "
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4-(Dimethylamino)phenyl ethynyl telluride
Joan Farran,Angel Alvarez-Larena,Joan F. Piniella,Mario V. Capparelli
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809009404
Abstract: The title compound, C10H11NTe, is the first organyl ethynyl telluride, R—Te—C[triple-bond]C—H, to be structurally characterized. In the L-shaped molecule, the aryl moiety, viz. Me2NC6H4Te, is almost perpendicular to the Te—C[triple-bond]C—H fragment. The Te—Csp2 bond [2.115 (3) ] is significantly longer than the Te—Csp bond [2.041 (4) ]. The Te—C[triple-bond]C group is approximately linear [Te—C—C = 178.5 (4)° and C[triple-bond]C = 1.161 (5) ], while the coordination at the Te atom is angular [C—Te—C = 95.92 (14)°]. In the crystal structure, there are Csp—H...N hydrogen bonds which are perpendicular to the CNMe2 group; the N atom displays some degree of pyramidalization. Centrosymmetrically related pairs of molecules are linked by Te...π(aryl) interactions, with Te...Cg = 3.683 (4) and Csp—Te...Cg = 159.1 (2)° (Cg is the centroid of the benzene ring). These interactions lead to the formation of zigzag ribbons which run along c and are approximately parallel to (110).
The Coastal Zone of Islands: Comparative Reflections from the North and South
Susan Farran
Island Studies Journal , 2006,
Abstract: Islanders tend to develop rules and methods for regulating the use of the marine environment and its accessible resources. Where islands have been subject to the influence or domination of external political forces, and such resources have become the subject of increased demand, then differences of approach, of understanding and of patterns of use can come into conflict. This is especially so where there is increased emphasis on coastal development, pressures to privatize and register coastal land and to regulate the commercial exploitation of marine resources. This article considers the Shetland & Orkney Islands from the north and Fiji, Vanuatu and the Solomon Islands from the south, drawing out similarities and differences of legal approaches to key issues relevant to the foreshore and the coastal zone.
A Direct Numerical Simulation-Based Analysis of Entropy Generation in Turbulent Premixed Flames
Richard Farran,Nilanjan Chakraborty
Entropy , 2013, DOI: 10.3390/e15051540
Abstract: A compressible single step chemistry Direct Numerical Simulation (DNS) database of freely propagating premixed flames has been used to analyze different entropy generation mechanisms. The entropy generation due to viscous dissipation within the flames remains negligible in comparison to the other mechanisms of entropy generation. It has been found that the entropy generation increases significantly due to turbulence and the relative magnitudes of the augmentation of entropy generation and burning rates under turbulent conditions ultimately determine the value of turbulent second law efficiency in comparison to the corresponding laminar values. It has been found that the entropy generation mechanisms due to chemical reaction, thermal conduction and mass diffusion in turbulent flames strengthen with decreasing global Lewis number in comparison to the corresponding values in laminar flames. The ratio of second law efficiency under turbulent conditions to its corresponding laminar value has been found to decrease with increasing global Lewis number. An increase in heat release parameter significantly augments the entropy generation due to thermal conduction, whereas other mechanisms of entropy generation are marginally affected. However, the effects of augmented entropy generation due to thermal conduction at high values of heat release parameter are eclipsed by the increased change in availability due to chemical reaction, which leads to an increase in the second law efficiency with increasing heat release parameter for identical flow conditions. The combustion regime does not have any major influence on the augmentation of entropy generation due to chemical reaction, thermal conduction and mass diffusion in turbulent flames in comparison to corresponding laminar flames, whereas the extent of augmentation of entropy generation due to viscous dissipation in turbulent conditions in comparison to corresponding laminar flames, is more significant in the thin reaction zones regime than in the corrugated flamelets regime. However, the ratio of second law efficiency under turbulent conditions to its corresponding laminar value does not get significantly affected by the regime of combustion, as viscous dissipation plays a marginal role in the overall entropy generation in premixed flames.
Rational points, genus and asymptotic behaviour in reduced algebraic curves over finite fields
J. I. Farran
Mathematics , 1999,
Abstract: The number A(q) shows the asymptotic behaviour of the quotient of the number of rational points over the genus of non-singular absolutely irreducible curves over a finite field Fq. Research on bounds for A(q) is closely connected with the so-called asymptotic main problem in Coding Theory. In this paper, we study some generalizations of this number for non-irreducible curves, their connection with A(q) and its application in Coding Theory.
Decoding Algebraic Geometry codes by a key equation
J. I. Farran
Mathematics , 1999,
Abstract: A new effective decoding algorithm is presented for arbitrary algebraic-geometric codes on the basis of solving a generalized key equation with the majority coset scheme of Duursma. It is an improvement of Ehrhard's algorithm, since the method corrects up to the half of the Goppa distance with complexity order O(n**2.81), and with no further assumption on the degree of the divisor G.
The Effects of Perceptual Grouping and Category Boundary Salience on Location Memory  [PDF]
Emily K. Farran, Sarah C. Connell, Bhupinderjit K. Pharwaha
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.311143
Abstract: The type of information used to process spatial layouts was assessed by observing the effect of spatial category salience and perceptual grouping (a non-spatial category), on a location memory task. Participants (N = 64) learnt the pairings between twenty objects and twenty marked locations within a “house”. They then placed the objects in the remembered locations, without the aid of location markers. Spatial category salience was manipulated by presenting the house as an open space (no boundary condition) or by dividing the space into quadrants (boundary condition). Perceptual grouping was manipulated by using identical shapes (control condition) or sets of shapes which identified triads of objects (perceptual grouping condition). Both non-spatial and spatial categories improved location memory accuracy. The non- spatial category produced a prototype effect and the spatial category produced a subdivision effect. Different patterns of category dominance (spatial vs. non-spatial) were observed for level of accuracy compared to distortion effects.
Randers manifolds of positive constant curvature
Aurel Bejancu,Hani Reda Farran
International Journal of Mathematics and Mathematical Sciences , 2003, DOI: 10.1155/s0161171203111301
Abstract: We prove that any simply connected and complete Riemannian manifold, on which a Randers metric of positive constant flag curvature exists, must be diffeomorphic to an odd-dimensional sphere, provided a certain 1-form vanishes on it.
A Geometric characterization of Finsler manifolds of constant curvature
A. Bejancu,H. R. Farran
International Journal of Mathematics and Mathematical Sciences , 2000, DOI: 10.1155/s0161171200002179
Abstract: We prove that a Finsler manifold 𝔽m is of constant curvature K=1 if and only if the unit horizontal Liouville vector field is a Killing vector field on the indicatrix bundle IM of 𝔽m.
On the vertical bundle of a pseudo-Finsler manifold
Aurel Bejancu,Hani Reda Farran
International Journal of Mathematics and Mathematical Sciences , 1999, DOI: 10.1155/s0161171299226373
Abstract: We define the Liouville distribution on the tangent bundle of a pseudo-Finsler manifold and prove that it is integrable. Also, we find geometric properties of both leaves of Liouville distribution and the vertical distribution.
Cortical activity influences geniculocortical spike efficacy in the macaque monkey
Farran Briggs,W. Martin Usrey
Frontiers in Integrative Neuroscience , 2007, DOI: 10.3389/neuro.07.003.2007
Abstract: Thalamocortical communication is a dynamic process influenced by both presynaptic and postsynaptic mechanisms. In this study, we recorded single-unit responses from cortical neurons that received direct input from the lateral geniculate nucleus (LGN) to address the question of whether prior patterns of cortical activity affect the ability of LGN inputs to drive cortical responses. By examining the ongoing activity that preceded the arrival of electrically evoked spikes from the LGN, we identified a number of activity patterns that were predictive of suprathreshold communication. Namely, cortical neurons were more likely to respond to LGN stimulation when their activity levels increased to 30-40Hz and∕or their activity displayed rhythmic patterns (30 ms intervals) with increased power in the gamma frequency band. Cortical neurons were also more likely to respond to LGN stimulation when their activity increased 30-40 ms prior to stimulation, suggesting that the phase of gamma activity also contributes to geniculocortical communication. Based on these results, we conclude that ongoing activity in the cortex is not random, but rather organized in a manner that can influence the dynamics of thalamocortical communication.
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