4,538 research outputs found
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
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.
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
Recommended from our members
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
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