520 research outputs found
Two fast X-ray transients in archival Chandra data
We present the discovery of two new X-ray transients in archival Chandra
data. The first transient, XRT 110103, occurred in January 2011 and shows a
sharp rise of at least three orders of magnitude in count rate in less than 10
s, a flat peak for about 20 s and decays by two orders of magnitude in the next
60 s. We find no optical or infrared counterpart to this event in preexisting
survey data or in an observation taken by the SIRIUS instrument at the Infrared
Survey Facility 2.1 yr after the transient, providing limiting magnitudes of
J>18.1, H>17.6 and Ks>16.3. This event shows similarities to the transient
previously reported in Jonker et al. which was interpreted as the possible
tidal disruption of a white dwarf by an intermediate mass black hole. We
discuss the possibility that these transients originate from the same type of
event. If we assume these events are related a rough estimate of the rates
gives 1.4*10^5 per year over the whole sky with a peak 0.3-7 keV X-ray flux
greater than 2*10^-10 erg cm^-2 s^-1 . The second transient, XRT 120830,
occurred in August 2012 and shows a rise of at least three orders of magnitude
in count rate and a subsequent decay of around one order of magnitude all
within 10 s, followed by a slower quasi-exponential decay over the remaining 30
ks of the observation. We detect a likely infrared counterpart with magnitudes
J=16.70+/-0.06, H=15.92+/-0.04 and Ks=15.37+/-0.06 which shows an average
proper motion of 74+/-19 milliarcsec per year compared to archival 2MASS
observations. The JHKs magnitudes, proper motion and X-ray flux of XRT 120830
are consistent with a bright flare from a nearby late M or early L dwarf.Comment: Accepted for publication in MNRAS, 6 pages, 5 figure
Dynamic ductile to brittle transition in a one-dimensional model of viscoplasticity
We study two closely related, nonlinear models of a viscoplastic solid. These
models capture essential features of plasticity over a wide range of strain
rates and applied stresses. They exhibit inelastic strain relaxation and steady
flow above a well defined yield stress. In this paper, we describe a first step
in exploring the implications of these models for theories of fracture and
related phenomena. We consider a one dimensional problem of decohesion from a
substrate of a membrane that obeys the viscoplastic constitutive equations that
we have constructed. We find that, quite generally, when the yield stress
becomes smaller than some threshold value, the energy required for steady
decohesion becomes a non-monotonic function of the decohesion speed. As a
consequence, steady state decohesion at certain speeds becomes unstable. We
believe that these results are relevant to understanding the ductile to brittle
transition as well as fracture stability.Comment: 10 pages, REVTeX, 12 postscript figure
The effect of scleral search coil lens wear on the eye
BACKGROUND/AIM Scleral search coils are used to measure eye movements. A recent abstract suggests that the coil can affect the eye by decreasing visual acuity, increasing intraocular pressure, and damaging the corneal and conjunctival surface. Such findings, if repeated in all subjects, would cast doubt on the credibility of the search coil as a reliable investigative technique. The aim of this study was to reassess the effect of the scleral search coil on visual function.
METHODS Six volunteer subjects were selected to undergo coil wear and baseline measurements were taken of logMAR visual acuity, non-contact tonometry, keratometry, and slit lamp examination. Four drops of 0.4% benoxinate hydrochloride were instilled before insertion of the lens by an experienced clinician. The lens then remained on the eye for 30 minutes. Measurements of the four ocular health parameters were repeated after 15 and 30 minutes of lens wear. The lens was then removed and the health of the eye reassessed.
RESULTS No obvious pattern of change was found in logMAR visual acuity, keratometry, or intraocular pressure. The lens did produce changes to the conjunctival and corneal surfaces, but this was not considered clinically significant.
CONCLUSION Search coils do not appear to cause any significant effects on visual function. However, thorough prescreening of subjects and post-wear checks should be carried out on all coil wearers to ensure no adverse effects have been caused
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English individualism refuted - and reasserted: the land market of Earls Colne (Essex), 1550-1750
This is the author's post-print version of an article whose final and definitive form has been published in The Economic History Review. © 2003 Blackwell Publishing Ltd. The definitive version is available at: http://www3.interscience.wiley.com/journal/118509292/homeEarls Colne first came to the notice of historians through Macfarlane's study of its seventeenth-century vicar, Ralph Josselin, and then Macfarlane's use of evidence from the village in his The Origins of English Individualism (1978). This article presents preliminary results drawn from a computer-based reconstruction of the copyhold land market, 1546-1750, to contest Macfarlane's reading of the family-land bond in the manor. The familial possession of land over long periods is shown to be normal, and consistent with an active land market predominantly in smaller parcels. Little consolidation took place in the manor although some growth in holding size was achieved through subtenancy. Finally, the article asks whether the experience of copyholders is typical of the general.University of Central Lancashir
Short-term effects of corticosterone treatment on muscle protein synthesis in relation to the response to feeding
Sociologyâs missed opportunity: John Stuart-Glennieâs lost theory of the moral revolution, also known as the axial age
In 1873, 75 years before Karl Jaspers published his theory of the Axial Age in 1949, unknown to Jaspers and to contemporary scholars today, Scottish folklorist John Stuart Stuart-Glennie elaborated the first fully developed and nuanced theory of what he termed âthe Moral Revolutionâ to characterize the historical shift emerging roughly around 600 BCE in a variety of civilizations, most notably ancient China, India, Judaism, and Greece, as part of a broader critical philosophy of history. He continued to write on the idea over decades in books and articles and also presented his ideas to the fledgling Sociological Society of London in 1905, which were published the following year in the volume Sociological Papers, Volume 2. This article discusses Stuart-Glennieâs ideas on the moral revolution in the context of his philosophy of history, including what he termed âpanzooinismâ; ideas with implications for contemporary debates in theory, comparative history, and sociology of religion. It shows why he should be acknowledged as the originator of the theory now known as the axial age, and also now be included as a significant sociologist in the movement toward the establishment of sociology
A novel FAM83G variant from palmoplantar keratoderma patient disrupts WNT signalling via loss of FAM83G-CK1α interaction
Palmoplantar keratoderma (PPK) is a multi-faceted skin disorder characterized by the thickening of the epidermis and abrasions on the palms and soles of the feet. Among the genetic causes, biallelic pathogenic variants in the FAM83G gene have been associated with PPK in dogs and humans. Here, a novel homozygous variant (c.794G>C, p.Arg265Pro) in the FAM83G gene, identified by whole exome sequencing in a 60-year-old female patient with PPK, is reported. The patient exhibited alterations in the skin of both hands and feet, dystrophic nails, thin, curly and sparse hair, long upper eyelid eyelashes, and poor dental enamel. FAM83G activates WNT signalling through association with ser/thr protein kinase CK1α. When expressed in FAM83Gâ/â DLD1 colorectal cancer cells, the FAM83GR265P variant displayed poor stability, a loss of interaction with CK1α and attenuated WNT signalling response. These defects persisted in skin fibroblast cells derived from the patient. Our findings imply that the loss of FAM83G-CK1α interaction and subsequent attenuation of WNT signalling underlie the pathogenesis of PPK caused by the FAM83GR265P variant
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