Studies relating to the ß-disintegration of some heavy elements, using magnetic spectrometer of high collecting power.

In recent years the improved methods of nuclear spectroscopy have provided an increasing body of information about the modes of disintegration of both naturally occurring and artificially produced radio-elements. This has led to the development of nuclear models which are capable of interpreting the nuclear data in terms of the properties of the nuclear structure with some success. Spins and parities are assigned to nuclear energy levels, and selection rules have been formulated by which the observed decay properties can be explained fairly consistently. The properties of the nuclear levels can be established from a variety of measurements. In ß- and γ -ray spectroscopy these include the relative intensities and high energy end-points of the partial components of the ß-speetrum, determined by the method of Fermi analysis from the continuous spectrum produced in the (ß-decay of a parent nucleus, and the intensities, lifetimes and multipole nature of subsequent γ- transitions between higher and lower lying energy levels in the daughter nucleus. These γ-transitions give rise to internal conversion electrons which are superimposed as mono-energetic lines on the continuous ß-spectrum. The internal conversion electrons are formed through the interaction of a γ-ray of energy Eγ with an electron of the K, L, -shell of the product nucleus. The energy Eß of the electrons emitted from the shell is given by Eß = Eγ - Eₖ (or Eₗ ), where Eₖ' (or Eₗ', ) is the binding energy of the K, L, -shell electrons in the pro¬ duct atom. It is customary to speak of the conversion of the γ-rays although it is now recognised that the electron emission is a competitive decay process resulting from the mutual interaction of the overlapping nuclear and electronic wave functions. The relative conversion efficiencies for γ-rays in the different shells or sub-shells and the ratio of conversion electrons to photon de-excitations (the conversion coefficients) in an atom depend, along with their lifetimes, on the energy and multipole nature of the radiation. The absolute intensities of the conversion lines, together with theoretically or experimentally determined conversion coefficients, permit the total intensities of y-transitions to be calculated relative to the total number of ß-transitions. The energies and intensities of the ß- and γ-transitions in conjunction with γ-ray studies may then form the basis of a complete disintegration scheme, while measurements of the coincidence of ß- and γ-transitions may be made to decide conclusively between possible level schemes. The present investigations on the electron spectrum of heavy radio-elements were undertaken with a magnetic spectrometer and provide information on the energies and intensities of ß-transitions and internally converted γ-transitions. The spectrometer has recently been equipped with a γ-ray detector which, with the possibility of making ß-γ coincidence measurements, will extend its capabilities in future studies. The spectrometer was designed by Richardson (1, 2) and the performance has been investigated and described, by Braid and Richardson (3). A description of the spectrometer is given in Chapter 3 but those features that distinguish it from conventional ß-particle spectrometers will be mentioned here, together with those properties that determine the type of radio-element that can be most profitably investigated

Infertility problems and mental health symptoms in a community-based sample: depressive symptoms among infertile men, but not women

Most researchers agree that men’s and women’s experiences of infertility are fundamentally different, and impacts upon the nature of psychological distress encountered. However, design flaws, including non-random samples unrepresentative of the general population, compromise many existing studies. Data derived from a random general community sample provides prevalence of current infertility, and permits examination of longitudinal associations between mental health symptoms and infertility among 1,978 participants aged 28-32 years. In the previous 12-months, infertility was experienced by 2.1% and 5.4% partnered men and women. Infertility independently predicted depressive symptomatology in men, and anxiety symptoms among women. Gender differences were sustained, even controlling for prior depression and anxiety. Health professionals are encouraged to proactively enquire about affective symptoms experienced by both women and men with infertility problems

The Experience of Homecoming for U.K. Army Reservists, Following Prolonged Military Mobilisation: A Mixed Methods IPA & Q Sort Study

Background. There is a move towards increased use of Reservists for all aspects of U.K. military operations. The dominant research focus looks for the link between increased military service and negative outcomes and has suggested that Reservists are especially prone to problems of adjustment on homecoming. Research in to the effects of homecoming on Reservists was found to be a neglected topic in the literature. Research question. The aim of this research was to explore how members of the United Kingdom Army Reserve experience returning to civilian life (homecoming), following a period of prolonged military mobilization. Method. A mixed methods approach was utilized. Firstly, Interpretative Phenomenological Analysis (IPA) was conducted on six Reservists, in order to understand their personal experiences of homecoming. Q Methodology was then selected for the second phase, using the IPA themes as the primary source for the Q Set. A Q Sort was conducted with 20 Reservists, in order to deliver the shared subjective viewpoints pertaining to homecoming. Results. Six themes emerged from the IPA phase, describing homecoming in terms of; activities, adjustment, culture, emotions, reflection and values. The Q Sort phase distilled the six themes into four homecoming factors: reflection on personal growth; adjustment, not stress; sense making and personal circumstances. Conclusions. The experience of participating on military operations was generally found to be developmental, supporting the concept of post-traumatic growth. Minimal adjustment issues were reported on homecoming relating to experiences on operations. However, some participants reported partners and close family members could be adversely affected. Also, any homecoming issues were more as a consequence of other pre-existing factors

Effect of Four-Way Coupling on the Turbulence Field in Multi-Phase Channel Flows

This paper investigates and compares the effect of a solid, spherical particle phase on surrounding carrier fluids (air and water) in a turbulent channel flow. The fluid phase properties are chosen to represent a flow typical of the nuclear waste industry, with the flow modelled using the direct numerical simulation (DNS) code, Nek5000, at a shear Reynolds number of 180. A Lagrangian particle tracker is developed and implemented to simulate the dispersed phase, capable of accommodating two-way coupling between the fluid and discrete phase and inter-particle collisions (four-way coupling). In order to investigate the effect that the four-way coupled particulate phase has on the turbulence field, mean fluid velocities and turbulence intensity statistics are recorded. The work demonstrates that the introduction of two-way coupling does indeed impact slightly on the turbulence field. Specifically, it reduces the mean velocity profile and increases the streamwise turbulence intensity in the near-wall region. Upon the introduction of inter-particle collisions, the flow statistics studied show a negligible response. Collision density distributions are studied and a temporal migration to the near-wall region is observed. Along-side this, to investigate particle density-ratio effects, water-based results are contrasted with simulations in air. The way in which the flow statistics are modified are shown to differ in air and water. Finally, a DLVO agglomeration model is demonstrated, whereby particles colliding with enough energy to overcome the potential barrier are considered bound. This is applied to the four-way coupled flow with temporal distributions of agglomerate counts presented

Particle concentration and stokes number effects in multi-phase turbulent channel flows

This investigation examines the effect that particle concentration has on the dynamics of two-phase turbulent channel flows at low and high density ratios. In the literature, little explanation is offered for the existence of high particle turbulence intensities in the buffer layer and viscous sublayer for particles with high Stokes number. The present study aims to explore particle dynamics in those regions. The spectral element method DNS solver, Nek5000, is used to model the fluid phase at a shear Reynolds number Re=, Particles are tracked using a Lagrangian approach with inter-phase momentum exchange (two-way coupling). Mean fluid and particle velocity statistics are gathered and analysed to determine the effect of increasing both Stokes number and concentration. Results indicate that the system with the greater Stokes number (air) has a much larger impact on the mean streamwise velocity and turbulence intensity profiles. As the concentration is increased, the mean flow velocity and turbulence intensity are reduced in the bulk and increased very close to the wall. For the low Stokes system, there is negligible effect on the flow statistics at low concentration. One-way coupled solid-phase statistics indicate that particles in water follow the flow very closely. At the higher densityratio, particles lag behind the flow in the bulk, but overtake the flow in the near-wall region, where the existence of increased streamwise turbulence intensities is also observed. To elucidate the dynamics, concentrations and fluxes are analysed. Particles are observed to be distributed more densely close to the wall in air, compared to a reasonably uniform distribution in water. Finally, contour plots indicate that particles in air tend to congregate in regions of low streamwise fluid velocity, and the extent to which this differs between the two systems is then quantitatively measured

Making the case for mobile cognition: EEG and sports performance

In the high stakes world of International sport even the smallest change in performance can make the difference between success and failure, leading sports professionals to become increasingly interested in the potential benefits of neuroimaging. Here we describe evidence from EEG studies that either identify neural signals associated with expertise in sport, or employ neurofeedback to improve performance. Evidence for the validity of neurofeedback as a technique for enhancing sports performance remains limited. By contrast, progress in characterizing the neural correlates of sporting behavior is clear: frequency domain studies link expert performance to changes in alpha rhythms, whilst time-domain studies link expertise in response evaluation and motor output with modulations of P300 effects and readiness potentials. Despite early promise, however, findings have had relatively little impact for sports professionals, at least in part because there has been a mismatch between lab tasks and real sporting activity. After selectively reviewing existing findings and outlining limitations, we highlight developments in mobile EEG technology that offer new opportunities for sports neuroscience

Effect of Particle Diameter on Agglomeration Dynamics in Multiphase Turbulent Channel Flows

The present work uses a fully coupled direct numerical simulation-Lagrangian particle tracking solver in conjunction with an interaction energy-based deterministic agglomeration algorithm to determine the effect of particle diameter on the aggregation properties of a wall-bounded, particle-laden channel flow at shear Reynolds number, = 180. Three primary particle diameters are considered of relevance to the nuclear industry resembling 200µm - 400µm calcite particles dispersed in water, with a Hamaker constant of 3.8×10-20 J. The simulations are initialized with randomly dispersed particles of numbers calculated to ensure a constant volume fraction ΦP = 10-3. Analysis is focused on elucidating the collision and agglomeration behaviour throughout the channel flow over time. A statistically steady state for collision and agglomeration rate is observed 10 non-dimensional time units after the particles have been injected which persists until at least ∗=50. Results indicate a decrease in particle agglomeration efficiency as diameter is increased, which provides for a reduction in agglomeration rate at large time scales as the particles begin to aggregate and the mean agglomerate diameter increases. Further to this, the normalized number of collisions is similar in all simulations, with the smallest particles showing a slightly increased collision rate. Arguments associated with energy dispersed in collisions are presented to substantiate these findings. Collision rates across the channel are approximately constant with an increase close to the walls which, when normalized by the total number of primary particles, are actually favoured by smaller particles. Finally, agglomeration outcomes after a collision are shown to be more likely towards the channel centreline, since the particle dynamics in this region favour collisions with low relative velocity

Visitors’ and locals’ views of environmental management in Christchurch, New Zealand

The objective of the research presented in this report was to develop an understanding of visitors' and locals' views of environmental management in Christchurch. A total of 63 people were selected in a diverse, non-random sample with roughly equal proportions of men and women, and including 21 overseas visitors, 33 domestic visitors and 22 local people. Each subject sorted a pre selected set of structured photographs into nine piles, ranging from those that represented good environmental management to those that represented poor environmental management, to create their own Q sort. All Q sorts were factor analysed to identify three factors or views on environmental management. Subjects' attitudes, beliefs and expectations in making their selections were recorded in interviews and provide an additional basis for interpreting the three different factors. The themes distinctive to the factors, and the themes that are common to the factors, are discussed to develop some theoretical implications. Finally, a number of implications for policy are considered, in particular the need to retain a breadth of approaches to environmental management

Effect of CO2 Dilution on the Structure and Emissions from Turbulent, Non-premixed Methane-Air Jet Flames

This investigation gives a comparison of the variation of temperature and gas compositions in lifted, turbulent non-premixed methane–air jet flames firing vertically into still air with different carbon dioxide diluent concentrations in the fuel jet. The carbon dioxide mole fraction ranged from 0 to 0.22 and was varied with a fixed jet velocity so that dilution-induced extinction was achieved. The effect of the changes due to this dilution on the post-flame emissions was investigated. Similarly, visual observation of the changes in the flame structure in mixture fraction space at different diluent mole fraction has been studied. An examination of the changes in the flame length, lift-off height, flame temperature, composition, and on the emission indices of the species in the post-flame region were made. They showed an increase in the flame's lift-off height, a decrease in the overall flame length, a reduction in the flame temperature and a reduction in the NOx concentration at various levels of dilution of carbon dioxide in the fuel

Adult triclabendazole-resistant Fasciola hepatica: morphological changes in the tegument and gut following in vivo treatment with artemether in the rat model

A study has been carried out to determine the morphological changes to the adult liver fluke, Fasciola hepatica after treatment in vivo with artemether. Rats were infected with the triclabendazole-resistant Sligo isolate of F. hepatica, dosed orally with artemether at a concentration of 200mg/kg and flukes recovered at 24, 48 and 72h post-treatment (p.t.). Surface changes were monitored by scanning electron microscopy and fine structural changes to the tegument and gut by transmission electron microscopy. Twenty-four hours p.t., the external surface showed minor disruption, in the form of mild swelling of the tegument. The tegumental syncytium and sub-tegumental tissues appeared relatively normal. Forty-eight and seventy-two hours p.t., disruption to the tegumental system increased, with isolated patches of surface blebbing and reduced production of secretory bodies by the tegumental cells being the main changes seen. The gastrodermal cells showed a relatively normal morphology 24h p.t. By 48h, large numbers of autophagic vacuoles and lipid droplets were present. Autophagy increased in magnitude by 72h p.t. and substantial disruption to the granular endoplasmic reticulum was observed. Results from this study show that flukes treated in vivo with artemether display progressive and time-dependent alterations to the tegument and gut. Disruption to the gut was consistently and substantially more severe than that to the tegument, suggesting that an oral route of uptake for this compound predominates. This is the first study providing ultrastructural information on the effect of an artemisinin compound against liver fluk