Applying black hole perturbation theory to numerically generated spacetimes

Nonspherical perturbation theory has been necessary to understand the meaning of radiation in spacetimes generated through fully nonlinear numerical relativity. Recently, perturbation techniques have been found to be successful for the time evolution of initial data found by nonlinear methods. Anticipating that such an approach will prove useful in a variety of problems, we give here both the practical steps, and a discussion of the underlying theory, for taking numerically generated data on an initial hypersurface as initial value data and extracting data that can be considered to be nonspherical perturbations.Comment: 14 pages, revtex3.0, 5 figure

Toward an anisotropic atom-atom model for the crystalline phases of the molecular S8 compound

We analize two anisotropic atom-atom models used to describe the crystalline alpha,beta and gamma phases of S8 crystals, the most stable compound of elemental sulfur in solid phases, at ambient pressure and T<=400 K. The calculations are performed via a series of classical molecular dynamics (MD) simulations, with flexible molecular models and using a constant pressure-constant temperature algorithm for the numerical simulations. All intramolecular modes that mix with lattice modes, and are therefore relevant on the onset of structural phase transitions, are taken into account. Comparisons with experimental data and previous results obtained with an isotropic atom-atom molecular model are also performed.Comment: Major changes, new simulations and figures added, revtex4, to appear in J. Chem. Phy

Plasmonic Scaling of Superconducting Metamaterials

Superconducting metamaterials are utilized to study the approach to the plasmonic limit simply by tuning temperature to modify the superfluid density, and thus the superfluid plasma frequency. We examine the persistence of artificial magnetism in a metamaterial made with superconductors in the plasmonic limit, and compare to the electromagnetic behavior of normal metals as a function of frequency as the plasma frequency is approached from below. Spiral-shaped Nb thin film meta-atoms of scaled dimensions are employed to explore the plasmonic behavior in these superconducting metamaterials, and the scaling condition allows extraction of the temperature dependent superfluid density, which is found to be in good agreement with expectations.Comment: 5 pages, 3 figure

Black hole collisions from Brill-Lindquist initial data: predictions of perturbation theory

The Misner initial value solution for two momentarily stationary black holes has been the focus of much numerical study. We report here analytic results for an astrophysically similar initial solution, that of Brill and Lindquist (BL). Results are given from perturbation theory for initially close holes and are compared with available numerical results. A comparison is made of the radiation generated from the BL and the Misner initial values, and the physical meaning is discussed.Comment: 11 pages, revtex3.0, 5 figure

Studies in physiology

Abrahams, V. C., and Pickford, M. 1953. Simultaneous observations on urine flow and uterine activity in the conscious bitch. J. Physiol. 122: 56P. • • Abrahams, V. C., and Pickford, M. 1954. Simultaneous observations on the rate of urine flow and spontaneous uterine movements in the dog, and their relationship to posterior lobe activity. J. Physiol. 126: 329-346. • • Abrahams, V. C., and Pickford, M. 1955. Observations on the flow of fluid through the ureter of the dog. J. Physiol. 128: 82P. • • Abrahams, V. C., Durnin, J. V. G. A., Garry, R. C., Mahadeva, K., Passmore, R.,.Watt, J. A., and de V. Weir, J. B. 1955. Part I. The balance of energy. In: M.R.C. Special Report Series 289: 1-19. (Studies on expendi¬ ture of energy and consumption of food by miners and clerks. Fife, Scotland, 1952. Garry, R. C., Passmore, R., Warnock, G. M. , and Durnin, J. V. G. A.). • • Abrahams, V. C., and Pickford, M. 1956. The effect of 5-hydroxytryptamine on the excretion of water in conscious dogs. Brit. J. Pharmacol. 11: 35-43. • • Abrahams, V. C., and Pickford, M. 1956. The effect of 5-hydroxytryptamine on pressure of dogs; and of adrenaline, pituitary extracts on the ureter. Brit. J. Pharmacol. 11: 44-49. • • Abrahams, V. C., and Pickford, M. 1956. The effect of 5-hydroxytryptamine on the uterus of conscious and of anaesthetized dogs. Brit. J. Pharmacol. 11: 50-51. • • Abrahams, V. C., and Pickford, M. 1956. Observations on a central antagonism between adrenaline and acetylcholine. J. Physiol. 131: 712-718. • • the ureter and on the blood noradrenaline, and posterior Abrahams, V. C., and Pickford, M. 1956. The effect of anticholinesterases injected onto the supraoptic nuclei of chloralosed dogs on the release of the oxytocic factor of the posterior pituitary. J. Physiol. 133: 330-333. • • Abrahams, V. C., Koelle, G. B., and Smart, P. 1957. Histochemical demonstration of cholinesterases in the hypothalamus of the dog. J. Physiol. 139: 137-144. • • Abrahams, V. C., and Hilton, S. M. 1957. Active muscle vasodilatation and its relation to the 'Flight and Fight reactions' in the conscious animal. J. Physiol. jU+O: 16-17P. • • Abrahams, V. C., and Pickford, M. 1958. The effect of distension of the uterus on the composition of urine of conscious dogs. J. Physiol. 141: 527-534. • • Abrahams, V. C. 1958. Venous temperature registration, and its use as an index of muscle blood flow. J. Physiol. 145: 20P. • • Abrahams, V. C., Hilton, S. M., and Zbrozyna, A. 1959. Active muscle vasodilatation elicited by mesencephalic stimulation. J. Physiol. 148: 32-33P. • • Abrahams, V. C., Hilton, S. M., and Malcolm. J. L. 1959. Sensory input to hypothalamic and mesencephalic regions subserving the defence reaction. J, Physiol. 149: 45-46P. • • Abrahams, V. C., Hilton, S. M., and Zbrozyna, A. 1960. Reflex activation of vasodilator nerve fibres to skeletal muscle in decerebrate and intact cats. J. Physiol. 152: 54-55P. • • Abrahams, V. C., Hilton, S. M., and Zbrozyna, A. 1960. Active muscle vasodilatation produced by stimulation of the brain stem: its significance in the defence reaction. J. Physiol. 154: 491-513. • • Abraharns, V. C. , Hilton, S. M. , and Malcolm, J. L. 1961. The significance of afferent collaterals to the central greymatter, mid-brain tegmentum and hypothalamus in the reflex activation of the defence reaction. Exc. Medica., Int. Congr. Series, #37. Fifth Int. Congr. EEG and Clin. Neurophysiol. (September 1961). • • Abrahams, V. C., and Hilton, S. M. 1962. Blocking action of decamethonium at different sites in the auto¬ nomic nervous system of the cat. Brit. J. Pharmacol. S Chemother. 1_8: 194-203. • • Abrahams, V. C., Hilton, S. M., and Malcolm, J. L. 1962. Sensory connexions to the hypothalamus and mid-brain, and their role in the reflex activation of the defence reaction. J. Physiol. 164: 1-16. • • Abrahams, V. C., and Edery, H. 1962. Electrical activity in the brain stem of cats during eserine perfusion of the cerebral ventricles. J. Physiol. 163: 11P. • • Abrahams, V. C. 1962. Histochemical localization of cholinesterases in some brain stem regions of the cat. J. Physiol. 165: 55P. • • Abrahams, V. C., and Langworth, E. P. 1963. Interactions between evoked potentials and background electrical activity in the hypothalamus of the cat. J. Physiol. 167: 24-25P. • • Abrahams, V. C., Langworth, E. P., and McDonald, M. 1962. Interactions between evoked potentials and background electrical activity in the brain stem of the cat. Its effect on 'computer averaging'. J. Physiol. 168: 12-13P. • • Abrahams, V. C., and Edery, H. 1964. Brain stem electrical activity and the release of acetylcholine. Progr. in Brain Res. 6_: 26-36. Bargmann, W. , and Schade, J. P., eds. Elsevier Publishing Co., Amsterdam, 1964. • • Abrahams, V. C., Hilton, S. M., and Zbrozyna, Z. 1964. The role of active muscle vasodilatation in the alerting stage of the defence reaction. J. Physiol. 171: 189-202. • • Abrahams, V. C., Langworth, E. P., and Theobald, G. W. 1964. Potentials evoked in the hypothalamus and cerebral cortex by electrical stimulation of the uterus. Nature 203: 654-656. • • Abrahams, V. C., and Langworth, E. P. 1965. A note on the use of computer averaging in the assessment of centrally acting drugs. Proc. 3rd Hungarian Conf. for Therapy & Pharm. Res., 204-209. • • Williams, R. L., and Abrahams, V. C. 1965. Patterns of circulatory change elicited by electrical stimulation of the medulla in chloralosed cats. Proc. Can. Fed. Biol. Soc. 8_: 21. • • Abrahams, V. C., and Mcintosh, J. 1965. Synchronous potentials evoked in widespread brain stem regions of conscious cats by visual, auditory and cutaneous stimuli. Proc. Can. Fed. Biol. Soc. 8:13. • • Abrahams, V. C., and Falchetto, S. 1966. The effect of stimulus modality and position on the discharge of units in the superior colliculus. Proc. Can. Fed. Biol. Soc. 9: 47. • • Abrahams, V. C. 1966. The form of averaged evoked potentials in the chloralosed cat and the effect of background activity. Proc. Can. Fed. Biol. Soc. 9: 47. • • Abrahams, V. C. 1966. Some factors affecting the form of averaged evoked potentials. J. Physiol. 185: 60-61P. • • Abrahams, V. C., and Falchetto, S. 1966. Patterns of unit response in the cat superior colliculi elicited by non-visual stimuli. The Physiologist 9: 128. • • Abrahams, V. C. , and Williams, R. L. 1967. Blood flow, heart rate, and blood pressure alterations elicited by direct electrical stimulation of lower brain stem. J. Physiol. 189: 58-59P. • • Abrahams, V. C. , and Langworth, E. P. 1967. The contribution of background electrical activity to the form of averaged evoked potentials in chloralose anaesthetized cats. Exp. Neurol. 18: 253-266. • • Abrahams, V. C. and Falchetto, S. 1967. Hind leg ataxia following section of a nerve to a neck extensor muscle. Proc. Can. Fed. Biol. Soc., 10: 145. • • Abrahams, V. C. 1968. Cervico-lumbar spinal interactions involving a brain pathway. Proc. Can. Fed. Biol. Soc., 11: 74. • • Abrahams, V. C., Butler, D. and Falchetto, S. 1968. A spinal-brain-spinal reflex and hind limb ataxia of cervical origin. Fed. Proc. , 27: #2. • • Abrahams, V. C., Milligan, J. V. and Falchetto, S. 1968. Determination of "significant" differences in unit discharge patterns. Proc. Can. Soc. Med. Biol. Eng. • • Abrahams, V. C. and Falchetto, S. 1968. Ataxia of the hind limbs of the cat following section of nerves to a neck extensor muscle and a possible reflex substrate. Proc. 24th Int. Congr. Physiol. Sci. • • Abrahams, V. C., Butler, D. and Daynes, J. 1969. A cortical relay site in cervico-lumbar interactions in cats. Proc. Can. Fed. Biol. Soc., 12: 55. • • Abrahams, V. C., Butler, D. and Daynes, J. 1969. Proprioceptive relays to the cerebral cortex and their significance in intraspinal organization. The Physiologist, 12: 154. • • Abrahams, V. C. 1969. Pathways involved in potentiation of lumbo-sacral reflexes by biventer cervicis nerve stimulation. Proc. Can. Physiol. Soc. • • Abrahams, V. C. and Falchetto, S. 1969. Hind leg ataxia of cervical origin and cervico-lumbar spinal interactions with a supratentorial pathway. J. Physiol. 203: 435-447. • • Abrahams, V. C. 1969. Proprioceptive projection areas of the cerebral cortex and their relation to cervico-lumbar spinal interactions. J. Physiol., 204: 82-83. • • Abrahams, V. C. and Teare, J. L. 1969. Peripheral pathways and properties of uterine afferents in the cat. Can. J. Physiol, and Pharmacol., 47: 576-577. • • Jagannthan, T., Foote, J., Abrahams, V. C., Bruce, A. W., Hetherington, R. F., Lywood, D. W. and English, C. J. 1969. A new approach to bladder evacuation: Studies in dogs. Inv. Urol., 7: 15-22. • • Abrahams, V. C. 1969. Intraspinal mechanisms in cortically mediated descending cervicolumbar reflex interactions. Can. Physiol., 1: 37. • • Abrahams, V. C. 1970. Computers in Medical Diagnosis. IEEE, Student J., 8: 35-38. • • Abrahams, V. C. 1970. Cervico-lumbar reflex interactions involving a proprioceptive receiving area of the cerebral cortex. J. Physiol., 209: 45-56. • • Abrahams, V. C. 1970. Intraspinal excitability changes during cortically mediated descending cervico-lumbar reflex interactions. Fed. Proc. 29_: #824, p.391. • • Abrahams, V. C. 1970. Individual mechanisms activated in descending spino-spinal activity in the chloralose anaesthetized cat. J. Physiol., 210: 175-176. • • Abrahams, V. C. 1971. Spino-spinal mechanisms in the chloralose anaesthetized cat. J. Physiol., 215: 755-768. • • Abrahams, V. C. 1971. Some effects on vestibulo-spinal outflow at lumbosacral levels from neck muscle afferents. J. Physiol., 215: 49-50. • • Rose, P. K. and Abrahams, V. C. 1972. Some characteristics of the neck muscle proprioceptive input to the superior colliculus of the cat. Can. Fed. Biol. Soc., 15: #732. • • Abrahams, V. C. 1972. Site of fixation in the spinal cord of the cat. Can. Fed. Biol. Soc., 1_5: #693. • • Abrahams, V. C. and Rose, P. K. 1972. Proprioceptive connections to the superior colliculi of the cat. Fed. Proc., 31: 383, #929. • • Abrahams, V. C. 1972. Neck muscle proprioceptors and a role of the cerebral cortex in postural reflexes in subprimates. Rev. Can. Biol., 31_: suppl., 115-130. • • Abrahams, V. C. 1972. Neck muscle proprioceptives and vestibulospinal outflow at lumbosacral levels. Can. J. Physiol, and Pharmacol., 50: 17-21. • • Abrahams, V. C. and Daynes, J. 1972. Fixation of inhibition of a spinal reflex by electrical stimulation of the medulla.' Soc. Neurosc., 2nd Ann. Meeting, p. 204. • • Abrahams, V. C. and Rancier, F. 1973. ATPase distribution in dorsal neck muscles of the cat. Can. J. Physiol, and Pharmacol. 51: 549-552. • • Rose, P. K. and Abrahams, V. C. 1973. An electrophysiological demonstration of extraocular muscle receptor projections to the superior colliclus in the cat. Can. Physiol., 4: 47. • • Rose, P. K. and Abrahams, V. C. 1973. Extraocular muscle proprioceptive projections to the superior colliculus in the cat. Fed. Proc. 32: 340, #698. • • Abrahams, V. C. and Rose, P. K. 1973. Afferent connections of cells in the superior colliculus of the cat giving rise to the tectospinal tract. Soc. Neurosc., 3rd Ann. Meeting, p. 336. • • Abrahams, V. C. 1974. On the induction of prolonged change in the functional state of the spinal cord. Advances in Neurology, Vol. 4, Pain. Raven Press, New York, pp. 243-251. • • Abrahams, V. C., Rancier, F., and Rose P. K. 1974. Neck muscle and extraocular receptors and their relationship to the tectospinal tract. Advances in Behavioural Biology, 7: 191. Plenum Publishing Corporation. • • Richmond, F. J. and Abrahams, V. C. 1974. Muscle spindles in the dorsal neck muscles of the cat. Can. Physiol. 4: 204. Rose, P. K. and Abrahams, V. C. 1974. Afferent connections to systems descending to neck motoneurons. Can. Physiol. 4: 205. • • Abrahams, V. C., Richmond, F. J. and Rose, P. K. 1974. Proprioceptive and retinal afferent connections to the superior colliculus of the cat and their connections to the tectospinal tract. J. Physiol. 244: 101. • • Abrahams, V. C., Richmond, F. J. and Rose, P. K. 1974. Basic physiology of the head-eye movement system. Wenner-Gren Symposium Series: Basic Mechanisms of Ocular Motility and Their Clinical Implications. Eds. G. Lennerstrand and P. Bach-y-rita. Pergamon Press, Oxford, 1975. • • Richmond, F. J. and Abrahams, V. C. 1974. Enzyme distribution in extrafusal fibres of cat dorsal neck muscles. Fed. Proc., 33: 103. • • Abrahams, V. C. and Rose, P. K. 1974. Fore and hind-limb muscle afferent projections to the superior colliculus of the cat. J. Physiol. 244: 45. • • Abrahams, V. C. and Rose, P. K. 1974. Medullary projections of Gp I and II afferents from neck muscle in the cat. Soc. Neurosc., 4th Ann. Meeting, p. 111. • • Abrahams, V. C. and Rose, P. K. 1975. Projections of extraocular, neck muscle, and retinal afferents to superior colliculus in the cat: their connections to the cells of origin of the tectospinal tract. J. Neurophysiol. 38: 10-18. • • Abrahams, V. C. and Rose, P. K. 1975. The spinal course and distribution of fore and hind-limb muscle afferent projections to the superior colliculus of the cat. J. Physiol. 247: 117-130. • • Abrahams, V. C. and Rose, P. K. 1975. The effect of passive eye movement on unit discharge in the superior colliculus of the cat. Brain Research, 974 95-106. • • Abrahams, V. C. and Rose, P. K. 1975. Velocity and displacement characteristics of passive eye movements which initiate unit discharge in the superior colliculus. J. Physiol. 246: 101. • • Abrahams, V. C., Richmond, F. J. and Rose. P. K. 1975. Absence of monosynaptic reflex in dorsal neck muscles of the cat. Brain Research 92: 130-131. • • Rose, P. K. and Abrahams, V. C. 1975. Spinal and medullary projections of afferents from dorsal neck muscles. Can. Physiol. 6: 50. • • Richmond, F. J. and Abrahams, V. C. 1975. Muscle spindle complexes in the dorsal muscles of the cat neck. Can. Physiol. 6: 48. • • Richmond, F. J. and Abrahams, V. C. 1975. The distribution and morphology of muscle spindles in dorsal neck muscles of the cat. Fed. Proc., 34: 388. • • Richmond, F. J. and Abrahams, V. C. 1975. Morphology and Enzyme Histochemistry of dorsal muscles of the cat neck. J. Neurophysiol., 38: 1312-1321. • • Richmond, F. J. and Abrahams, V. C. 1975. Morphology and distribution of muscle spindles in dorsal muscles of the cat neck. J. Neurophysiol., 38: 1322-1339. • • Rose, P. K. and Abrahams, V. C. 1975. Unit response in the superior colliculus and its relationship to activation of receptors in extraocular muscle. Proc. Fed. Biol. Soc., 18: 147. • • Abrahams, V. C. 1975. Proprioceptive projections to the spinal nucleus of the Vth nerve in the cat. Proceedings of First World Congress of the International Association for the Study of Pain. • • Abrahams, V. C. and Richmond, F. J. 1975. The organization of muscle afferent and cutaneous input to the upper cervical cord in the cat. 5th Annual Meeting, Society for Neuroscience, Neuroscience Abstract 1_, #248, p. 160. • • Richmond, F. J. and Abrahams, V. C. 1976. Physiological properties of dorsal muscles of the cat neck. Fed. Proc., 3_5: 291. • • Abrahams, V. C. and Rose, P. K. 1976. Tectospinal and tectoreticular cells their distribution and afferent connections. Fed. Proc., 35: 484. • • Abrahams, V. C., Anstee, G. and Richmond, F. J. 1976. Further studies on the organization of the upper cervical cord. Proc. Can. Fed. Biol. Soc., 19th Ann. Meeting, 1976. Richmond, F. J. and Abrahams, V. C. 1976. Physiological properties of dorsal muscles of the cat neck. Can. Physiol., 7: 50. • • Anstee, G. C. B., Richmond, F. J. and Abrahams, V. C. 1976. Sensory and motor fibre spectra of neck muscle nerves in the cat. Can. Physiol., 7: 16. • • Richmond, F. J., Anstee, G. B. C., Sherwin, L., and Abrahams, V. C. 1976. Motor and sensory fibres of neck muscle nerves in the cat. Can. J. Physiol, and Pharmacol., 54: 294-304. • • Abrahams, V. C., Richmond, F. J. and Rose, P. K. 1977. Spinal and medullary projections from neck muscle afferents in the cat. J. Neurophysiol. - manuscript for submission. • • Abrahams, V. C. 1977. The motor system of the head. A short review. In press. • • Rose, P. K. and Abrahams, V. C. 1977. Tectospinal and tectoreticular cells. A comparison of their distribution within the superior colliculus and their afferent connections. J. Neurophysiol., - manuscript for submission

Waveform propagation in black hole spacetimes: evaluating the quality of numerical solutions

We compute the propagation and scattering of linear gravitational waves off a Schwarzschild black hole using a numerical code which solves a generalization of the Zerilli equation to a three dimensional cartesian coordinate system. Since the solution to this problem is well understood it represents a very good testbed for evaluating our ability to perform three dimensional computations of gravitational waves in spacetimes in which a black hole event horizon is present.Comment: 13 pages, RevTeX, to appear in Phys. Rev.

Do we need more evidence-based survey guidance?

As ecologists and environmental managers, we rely on good quality baseline information. However, the survey methods we currently employ are often unsupported by scientific testing and are not proven to provide high quality outputs. As a community of practitioners, we should seek to change this, taking on board new research and technological developments – and building more evidence explicitly into our survey guidance

Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in Phys. Rev. Let