257 research outputs found
Spin density matrix element extraction for the p°vector meson on hydrogen and deuterium targets at HERMES
The HERMES experiment in Hamburg, Germany, consists of a large forward spectrometer which studies various physics processes related to the nucleon and its internal structure. The main focus of the analysis presented in this thesis is based on the angular decay distributions of the decay products of the Ď0 vector meson. By examining the angular decay of the outgoing decay products the Spin Density Matrix Elements (SDMEs) for the Ď 0 can be determined. The extraction of the Ď0 data sample from the raw HERMES output data is explained and the method used to extract exclusive, diffractive Ď0s is given. The analysis procedure and the method used to analyse the data samples is then explained with consideration given to the description of the method used to extract the spin density matrix elements. In the autumn of 2005 a new detector known as the Recoil Detector will be commissioned in the front region of the HERMES experiment. The Recoil Detector will advance the analysis presented in this thesis in some regards, ie the improved t-resolution at low t which will improve exclusive measurements including vector meson production. Several contributions to the Recoil Detector are presented in detail. In particular the research of the HELIX128-3.0 readout chip and its development towards the final readout of the silicon detector and the integration of the Recoil Detector into the Hermes Monte Carlo
Impact of maternal psychological distress and parental bonding on mother-adolescent agreement about emotional problems
Objective. To explore the impact of parent psychological distress and
parental bonding on agreement between informants about adolescent
emotional functioning.
Methods. The study employed an observational design in which 87 pairs of
mothers and their adolescent sons or daughters aged 12-17 completed proxyand
self-report ratings on the Strengths and Difficulties Questionnaire.
Mothers also completed the Depression, Anxiety and Stress scale as a measure
of their own psychological distress, and adolescents completed the Parental
Bonding Instrument as a measure of their parenting experience. Moderation
analyses using multiple linear regression were used to assess whether the
association between maternal psychological distress and mother-adolescent
agreement changed as a factor of parental bonding.
Results. Kappa values indicated that mother-adolescent agreement was âfairâ
for emotional problems. Mothersâ psychological distress and sub-optimal
parenting were both associated with greater reporting discrepancies. Maternal
psychological distress and perceived maternal were unique and combined
predictors of reporting discrepancies. Perceived care moderated the
relationship between maternal distress and agreement such that when care was rated as low, higher levels of maternal distress predicted poor agreement,
but when care was rated as high no significant relationship was found between
distress and agreement.
Conclusions. Increased mother-adolescent agreement was associated with
lower maternal psychological distress and higher ratings of perceived care.
The effect of psychological distress on informant agreement varied as a factor
of perceived maternal care. Results of this study support the need for multiinformant
assessment and suggest that enquiry about mothersâ own
psychological functioning could facilitate accurate assessment and
intervention for adolescents who present at psychology services
Novel muon imaging techniques
Owing to the high penetrating power of high-energy cosmic ray muons, muon imaging techniques can be used to image large bulky objects, especially objects with heavy shielding. Muon imaging systems work just like CT scanners in the medical imaging fieldâthat is, they can reveal information inside of a target. There are two forms of muon imaging techniques: muon absorption imaging and muon multiple scattering imaging. The former is based on the flux attenuation of muons, and the latter is based on the multiple scattering of muons in matter. The muon absorption imaging technique is capable of imaging very large objects such as volcanoes and large buildings, and also smaller objects like spent fuel casks; the muon multiple scattering imaging technique is best suited to inspect smaller objects such as nuclear waste containers. Muon imaging techniques can be applied in a broad variety of fields, i.e. from measuring the magma thickness of volcanoes to searching for secret cavities in pyramids, and from monitoring the borders of countries checking for special nuclear materials to monitoring the spent fuel casks for nuclear safeguards applications. In this paper, the principles of muon imaging are reviewed. Image reconstruction algorithms such as Filtered Back Projection and Maximum Likelihood Expectation Maximization are discussed. The capability of muon imaging techniques is demonstrated through a Geant4 simulation study for imaging a nuclear spent fuel cask
Muography applied to nuclear waste storage sites
Legacy storage sites for nuclear waste can pose a serious environmental problem. In fact, since certain sites date from the middle of the last century when safety protocols had not been properly established and strict bookkeeping was not enforced, a situation has evolved where the content of storage silos is basically known only with a large uncertainty both on quantity and quality. At the same time maintenance work on old storage structures is becoming ever more urgent and yet this work requires exactly that information which is now lacking on the type of waste that was stored inside. Because of the difficulty in accessing the storage silos and the near impossibility of making visual inspections inside, techniques have to be developed which can determine the presence or absence of heavy elements (i.e. uranium) within the structures. Muography is a very promising technique which could allow the survey of previously inaccessible structures. We have begun an evaluation performing feasibility studies using simulations based on real case scenarios. This paper will outline the storage site scenarios and then present some of the results obtained from the Monte Carlo simulations
Time since fire and average fire interval are the best predictors of Phytophthora cinnamomi activity in heathlands of south-western Australia
Fires are features of ecological communities in much of Australia; however, very little is still known about the potential impact of fire on plant diseases in the natural environment. Phytophthora cinnamomi is an introduced soil-borne plant pathogen with a wide host range, affecting a large proportion of native plant species in Australia and other regions of the world, but its interaction with fire is poorly understood. An investigation of the effects of fire on P. cinnamomi activity was undertaken in the Stirling Range National Park of south-western Australia, where fire is used as a management tool to reduce the negative impact of wildfires and more than 60% of the park is infested with, and 48% of woody plant species are known to be susceptible to, P. cinnamomi. At eight sites confirmed to be infested with P. cinnamomi, the proportion of dead and dying susceptible species was used as a proxy for P. cinnamomi activity. Subset modelling was used to determine the interactive effects of latest fire interval, average fire interval, soil water-holding capacity and pH on P. cinnamomi activity. It was found that the latest and average fire interval were the variables that best explained the variation in the percentage of dead and dying susceptible species among sites, indicating that fire in P. cinnamomi-infested communities has the potential to increase both the severity and extent of disease in native plant communities
Characterising encapsulated nuclear waste using cosmic-ray muon tomography
Tomographic imaging techniques using the Coulomb scattering of cosmic-ray
muons have been shown previously to successfully identify and characterise low-
and high-Z materials within an air matrix using a prototype scintillating-fibre
tracker system. Those studies were performed as the first in a series to assess
the feasibility of this technology and image reconstruction techniques in
characterising the potential high-Z contents of legacy nuclear waste containers
for the UK Nuclear Industry. The present work continues the feasibility study
and presents the first images reconstructed from experimental data collected
using this small-scale prototype system of low- and high-Z materials
encapsulated within a concrete-filled stainless-steel container. Clear
discrimination is observed between the thick steel casing, the concrete matrix
and the sample materials assayed. These reconstructed objects are presented and
discussed in detail alongside the implications for future industrial scenarios.Comment: 6 pages, 4 figure
The Ursinus Weekly, February 11, 1963
President Emeritus McClure dies following recent illness: Dr. Yost pays tribute to his late colleague ⢠Dr. Donald Baker discusses US at Koffee Klatch ⢠Coed foursome discusses Summer with Indians ⢠President Helfferich quizzed in Controversy at midnight chat: Topics discussed include fraternities, government aid, college isolation, library ⢠Annual Lorelei dance scheduled for Friday evening at Sunnybrook ⢠Legal counselor slated to address PSEA ⢠Tennis coach displays art exhibit in Library ⢠Living under communism topic of Wednesday\u27s Forum speaker ⢠Bible Study film examines nature ⢠Powers & Fuges leave UC to enlist in Peace Corps ⢠Kachel, Berlinger elected 1964 Ruby business managers ⢠Chi Alpha hears talk on research ⢠Spring rushing periods begin for fraternities and sororities ⢠Editorial: End of an era; As youth should be spent ⢠Letters to the editor ⢠Silver scholarships offered to coeds ⢠Greek gleanings ⢠Spring Mountain ski slope offers fun for both beginners and experts ⢠Netmen downed by Haverford 80-66, eke out 65-63 win over Hopkins ⢠Tenacious play marks Hofmann ⢠Kratz versatile, solid, dependable ⢠Matmen stunned by E\u27towners in 17-11 upset ⢠Jayvee netwomen claim 46-38 win over Phila. Bible ⢠Intramural storyhttps://digitalcommons.ursinus.edu/weekly/1286/thumbnail.jp
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