15,273 research outputs found
An Effect of Cathode Rays on Photographic Paper
When photographic printing out or developing out paper is exposed to cathode rays in air (Lenard rays) for a sufficient time, it undergoes a color change similar to but not quite like that produced by exposure to light. It has been noted that, when a sample of the photographic paper is exposed to Cathode rays, it is rendered relatively insensitive to subsequent exposure to light. This peculiar effect is not observed when developing agents are used on the developing out paper, nor is it observed on blue print paper. Investigation indicates that the desensitizing effect of the cathode ray exposure can be simulated by application of heat, although the temperature to which the emulsion must be raised is surprisingly high. Experiments with other materials indicate that local temperatures in the rayed object may be very high. The importance of this finding has not been appreciated by those working in biological fields
A Study of Some of the Modern Natural Color Photographic Processes
The following additive processes have been investigated: Agfacolor, Dufaycolor, and Finlay. Conclusions are based largely upon experience obtained in the practical use of the processes. The two subtractive processes investigated were Eastman Wash-Off Relief and Defender Chromatone. Here a systematic attempt has been made to analyze the factors which control the results and to eliminate difficulties by some method of control
Evaluation of the sleep project for unaccompanied asylum-seeking children in Kent
It has been a privilege to evaluate the Sleep Project intervention for unaccompanied asylum-seeking children (UASC). The opportunity to evaluate this project arose through discussions between the authors and Dr. Ana Draper, exploring the work of Ana, her team and colleagues across the various agencies in supporting newly-arrived migrant children in Kent.
From 2015, there was a rapid increase in the number of UASC arriving into the region and services were quickly adapted to meet the specific and immediate needs of these vulnerable children and young people, the Sleep Project being just one of the innovative interventions put in place.
Unaccompanied asylum-seeking children and young people have usually experienced harrowing journeys to the United Kingdom (UK) in seeking safety and refuge. Once in the UK, adapting to life within reception centres, foster families or supported housing, brings further challenges and within this context, practitioners and the young people identified sleep as a key problematic issue for which they required extra support. Through conversations with practitioners and young people, sleep difficulties were a recurring issue. Lack of sleep and disturbed sleep was preventing the young people from engaging in planned activities such as language classes. Tiredness was having negative health and social/educational impacts.
This evaluation studies the benefits and challenges of the creative support mechanisms that were developed to address the sleep issues.
This report presents our findings from the evaluation study of the Sleep Project intervention. The study comprised of 18 interviews with practitioners either working directly or indirectly with UASC, in paid and voluntary capacities. From the interviews, the qualitative data was thematically analysed to develop themes under which the benefits and challenges of the intervention could be explored.
Throughout the interviews with practitioners working either directly with UASC or indirectly in managerial roles, it became apparent that there was a high level of commitment from individuals to develop their understanding of UASCsâ needs and to develop appropriate social care practice and support. The interviews highlighted that practitioners were prepared to think and act creatively to improve and to tailor support for this group of children and young people.
The findings of the evaluation suggest that the Sleep Project was very well-received by young people and practitioners alike. It provided practical resources and support for good sleep, and it encouraged conversations to develop between the practitioners and the young people, and between the young people themselves, normalising the sleep issues that they were experiencing, and, according to interviewees, the young people were found to be encouraging other young people to use the good sleep packs. The intervention helped the practitioners feel more confident and equipped with skills to talk to the young people about sleep and, possibly, this led to deeper discussions about individual journeys and experiences, allowing care to become more empathetic, specific and person-centred. Significantly, interviewees reported that the project allowed them to âlook at the basicsâ, that is, practical help such as providing night lights and educating young people about factors that hamper a good nightâs sleep, whilst practitioners gained a greater understanding and responsiveness as to why the young people could struggle with sleep. This greater understanding has been important for shifting the perceptions of practitioners, particularly those in educational roles, helping them to be more patient and supportive to young people struggling to get to lessons on time and to concentrate.
Key messages from the findings of this evaluation study are encapsulated in the following quotes from interviewees:
âą âI think itâs thinking a bit more innovatively about the care we can provideâ
âą âA confidence to look at the basicsâ
âą âContext switched conceptsâ.
Proposed recommendations involve: sustaining the work so far, looking at how the project could/should have a legacy, and building on the developed knowledge and networks. At the time of the publication of this report, young people are being transferred to other receiving local authorities outside Kent â a national dispersal scheme that was agreed by the Home Office in June 2016 to ease the pressure on Kent - therefore good practice from this project should be widely disseminated to service providers and policy makers at regional and national levels
Pricing and hedging of Asian options: Quasi-explicit solutions via Malliavin calculus
We use Malliavin calculus and the Clark-Ocone formula to derive the hedging strategy of an arithmetic Asian Call option in general terms. Furthermore we derive an expression for the density of the integral over time of a geometric Brownian motion, which allows us to express hedging strategy and price of the Asian option as an analytic expression. Numerical computations which are based on this expression are provided
Microwave Spectroscopy
Contains reports on two research projects.United States Army Signal Corps (Contract DA36-039-sc-74895
Effect of Piezo Electric Oscillations on X-Ray Patterns of Quartz
Experiments have been made to determine the amplitude of vibration of the atoms in a quartz lattice due to piezo electric oscillations. A series of Laue X-ray patterns have been made of quartz plates cut at various angles to the electric axes. Very marked intensity differences are apparent between the patterns made with the plates oscillating and not oscillating
Effect of Primordial Black Holes on the Cosmic Microwave Background and Cosmological Parameter Estimates
We investigate the effect of non-evaporating primordial black holes (PBHs) on
the ionization and thermal history of the universe. X-rays emitted by gas
accretion onto PBHs modify the cosmic recombination history, producing
measurable effects on the spectrum and anisotropies of the Cosmic Microwave
Background (CMB). Using the third-year WMAP data and FIRAS data we improve
existing upper limits on the abundance of PBHs with masses >0.1 Msun by several
orders of magnitude. Fitting WMAP3 data with cosmological models that do not
allow for non-standard recombination histories, as produced by PBHs or other
early energy sources, may lead to an underestimate of the best-fit values of
the amplitude of linear density fluctuations (sigma_8) and the scalar spectral
index (n_s). Cosmological parameter estimates are affected because models with
PBHs allow for larger values of the Thomson scattering optical depth, whose
correlation with other parameters may not be correctly taken into account when
PBHs are ignored. Values of tau_e=0.2, n_s=1 and sigma_8=0.9 are allowed at 95%
CF. This result that may relieve recent tension between WMAP3 data and clusters
data on the value of sigma_8. PBHs may increase the primordial molecular
hydrogen abundance by up to two orders of magnitude, this promoting cooling and
star formation. The suppression of galaxy formation due to X-ray heating is
negligible for models consistent with the CMB data. Thus, the formation rate of
the first galaxies and stars would be enhanced by a population of PBHs.Comment: 17 pages (Apj style), 9 figures, submitted to Ap
Self-Similar Collapse of Scalar Field in Higher Dimensions
This paper constructs continuously self-similar solution of a spherically
symmetric gravitational collapse of a scalar field in n dimensions. The
qualitative behavior of these solutions is explained, and closed-form answers
are provided where possible. Equivalence of scalar field couplings is used to
show a way to generalize minimally coupled scalar field solutions to the model
with general coupling.Comment: RevTex 3.1, 15 pages, 3 figures; references adde
Functional co-monotony of processes with applications to peacocks and barrier options
We show that several general classes of stochastic processes satisfy a
functional co-monotony principle, including processes with independent
increments, Brownian diffusions, Liouville processes. As a first application,
we recover some recent results about peacock processes obtained by Hirsch et
al. which were themselves motivated by a former work of Carr et al. about the
sensitivity of Asian Call options with respect to their volatility and residual
maturity (seniority). We also derive semi-universal bounds for various barrier
options.Comment: 27 page
Stability criterion for self-similar solutions with a scalar field and those with a stiff fluid in general relativity
A stability criterion is derived in general relativity for self-similar
solutions with a scalar field and those with a stiff fluid, which is a perfect
fluid with the equation of state . A wide class of self-similar
solutions turn out to be unstable against kink mode perturbation. According to
the criterion, the Evans-Coleman stiff-fluid solution is unstable and cannot be
a critical solution for the spherical collapse of a stiff fluid if we allow
sufficiently small discontinuity in the density gradient field in the initial
data sets. The self-similar scalar-field solution, which was recently found
numerically by Brady {\it et al.} (2002 {\it Class. Quantum. Grav.} {\bf 19}
6359), is also unstable. Both the flat Friedmann universe with a scalar field
and that with a stiff fluid suffer from kink instability at the particle
horizon scale.Comment: 15 pages, accepted for publication in Classical and Quantum Gravity,
typos correcte
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