3,969 research outputs found
The Age of the Woolly Rhino from Dream Cave, Derbyshire, UK
The Dream Cave woolly rhinoceros, Coelodonta antiquitatis, is a classic specimen of a cold-stage fossil fauna from central England. The find was illustrated and described by Dean William Buckland in his seminal tome Reliquiae Diluvianae (1823) during the first half of the 19th century, and made a significant contribution to the development of Buckland\u27s views on the origin of extinct and extirpated fossil vertebrates. The report presents the first, albeit indirect, radiometric dates on the specimen, and argues that the animal fell into the cave just before 37,000 years BP, during the middle of Marine Isotope Stage 3 Interstadial (41 - 39 ka BP)
Bomb-pulse radiocarbon dating of modern paintings on canvas
Radiocarbon (14C) dating has previously been applied to modern paintings on canvas from the 20th century to identify potential modern forgeries, and dates indicate a time lag of several years between the harvesting of plant fibers for making canvas, and completion of a painting. This study investigated both the length of this time lag and the potential of 14C dating to inform about an individual artist’s mode of working (for example long-term storage or reuse of canvases, or extended reworking on a single canvas) and/or to establish a chronology for a corpus of work. Two pre-bomb and 16 post-bomb artworks by 17 mid-20th-century Scandinavian artists were 14C dated. The majority of post-bomb samples indicated a time lag of 2–5 years between the harvesting of the plants and completion of a painting, but some samples recorded lags of up to 10 years, and others produced much earlier results, potentially indicating the use of much older canvases or challenges removing contamination prior to dating. The importance of thorough pre-screening of canvas samples for both synthetic fibers and contaminants prior to dating, and selection of the most suitable calibration curve, are highlighted
A Theoretical Approach to Financial Therapy: The Development of the Ford Financial Empowerment Model
The purpose of this paper is to introduce an integrative approach to working with clients experiencing problems related to financial disempowerment. The multi-phase model integrates three theoretically-driven psychotherapy approaches, including cognitive behavioral, narrative, and Virginia Satir’s experiential therapies, and financial counseling techniques to increase one’s sense of financial empowerment. A case study is included to demonstrate the applicability and effectiveness of the model
Quintessence, Supersymmetry and Inflation
Recent data point in the direction of a dominated universe. We
briefly review ``Quintessence'' as a model for a dynamical cosmological term
and analyse the role of Susy QCD as a possible particle physics candidate. The
multiscalar content of the theory is fully taken into account and interaction
with other cosmological fields is discussed. Finally, the possibility of
constructing a unified scheme for quintessence and inflation is mentioned.Comment: 5 LaTex pages, no figures; Talk given at the International Workshop
on "Particles in Astrophysics and Cosmology: from Theory to Observations"
(Valencia99), 3-8 May 1999, Valencia, Spain. To appear on Nucl. Phys. B,
Proc. Supp
Curvaton reheating mechanism in inflation on warped Dvali-Gabadadze-Porrati brane
An impressed feature of inflation on warped Dvali-Gabadadze-Porrati (DGP)
brane is that the inflationary phase exits spontaneously for a scalar inflaton
field with exponential potential, which presents a graceful exit mechanism for
the inflation. But its reheating mechanism leaves open. We investigate the
curvaton reheating in inflation on warped DGP brane model. The reheating may
occur in effctively 5 dimensional or 4 dimensional stage. We study the
permitted parameter space of the curvaton field in detail. We demonstrate how
the inflation model of the warped DGP brane is improved by the curvaton
mechanism.Comment: 10 pages, 7 figures, references adde
Extending mechanical thrombectomy service provision to 24/7: a break-even analysis
Background: Comprehensive stroke centres across England have developed investment proposals, showing the estimated increases in mechanical thrombectomy (MT) treatment volume that would justify extending the standard hours to a 24/7 service provision. These investment proposals have been developed taking a financial accounting perspective, that is by considering the financial revenues from tariff income. However, given the pressure put on local health authorities to provide value for money services, an affordability question emerges. That is, at what additional MT treatment volume the additional treatment costs are offset by the additional health economic benefits, that is quality-adjusted life years (QALYs) and societal cost savings, generated by administering MT compared to standard care. Methods: A break-even analysis was conducted to identify the additional MT treatment volume required. The incremental hospital-related costs associated with the 24/7 MT extension were estimated using information and parameters from four relevant business cases. The additional societal cost savings and health benefits were estimated by adapting a previously developed Markov chain-based model. Results: The additional hospital-related annual costs for extending MT to a 24/7 service were estimated at a mean of ÂŁ3,756,818 (range ÂŁ1,847,387 to ÂŁ5,092,788). On average, 750 (range 246 to 1,571) additional eligible stroke patients are required to be treated with MT yearly for the proposed 24/7 service extension to be affordable from a health economic perspective. Overall, the additional facility and equipment costs associated with the 24/7 extension would affect this estimate by 20%. Conclusions: These findings support the ongoing debate regarding the optimal levels of MT treatment required for a 24/7 extension and respective changes in hospital organisational activities. They also highlight a need for a regional-level coordination between local authorities and hospital administrations to ensure equity provision in that stroke patients can benefit from MT and that the optimal MT treatment volume is reached. Future studies should contemplate reproducing the presented analysis for different health service provision settings and decision making contexts
Quintessential inflation
We present an explicit observationally acceptable model for evolution from
inflation to the present epoch under the assumption that the entropy and matter
of the familiar universe are from gravitational particle production at the end
of inflation. This eliminates the problem of finding a satisfactory coupling of
the inflaton and matter fields. Since the inflaton potential may be a
monotonic function of the inflaton , the inflaton energy could produce an
observationally significant effective cosmological constant, as in
quintessence.Comment: 6 pages, REVTeX, 1 figur
Curvaton Reheating in Non-oscillatory Inflationary Models
In non-oscillatory (NO) inflationary models, the reheating mechanism was
usually based on gravitational particle production or the mechanism of instant
preheating. In this paper we introduce the curvaton mechanism into NO models to
reheat the universe and generate the curvature perturbation. Specifically we
consider the Peebles-Vilenkin quintessential inflation model, where the
reheating temperature can be extended from 1MeV to GeV.Comment: 4 pages, 1 figur
Curvaton reheating: an application to braneworld inflation
The curvaton was introduced recently as a distinct inflationary mechanism for
generating adiabatic density perturbations. Implicit in that scenario is that
the curvaton offers a new mechanism for reheating after inflation, as it is a
form of energy density not diluted by the inflationary expansion. We consider
curvaton reheating in the context of a braneworld inflation model, {\em steep
inflation}, which features a novel use of the braneworld to give a new
mechanism for ending inflation. The original steep inflation model featured
reheating by gravitational particle production, but the inefficiency of that
process brings observational difficulties. We demonstrate here that the
phenomenology of steep inflation is much improved by curvaton reheating.Comment: 8 pages RevTeX4 file with two figures incorporated. Improved
referencing, matches PRD accepted versio
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