On the generation and characterisation of internal micro-architectures

Open cell micro-architectures are used in a large number of applications, ranging from medical, such as bone scaffolds, to industrial, such as heat transfer structures. Traditionally these structures are manufactured using foaming processes, however advances in additive manufacturing (AM) now allow such structures to be designed computationally and fabricated to a high degree of precision. In this thesis image-based methods are developed for the purpose of generating periodic micro-architectures based on implicit representations. The algorithms developed are shown to be efficient and robust, allowing for the creation of both surface and volume meshes. Methods are presented for the creation of functionally graded structures allowing for arbitrary variations in density between specifiable volume fractions. These algorithms are further extended for domain conforming applications as well as for internal structures in CAD models. By utilising a hybrid approach, imaging techniques can be exploited for the generation of internal structures in CAD models without de-featuring the original external geometry. The structures of interest are also shown to be manufacturable via selective laser melting (SLM). The issue of characterisation, for linear elastic properties, is addressed through the use of a novel homogenisation technique. Large multi-scale problems in irregular domains are divided into smaller sub-volumes using established tetrahedral volume meshing techniques. By performing a series of virtual tests on these macroelements their effective properties can be computed and subsequently used in macro-simulations. The technique is shown to yield results in excellent agreement with the often used kinematic uniform boundary conditions (KUBC). It is also shown how these properties may be used for visualising the distribution in properties over a domain.SimplewareEPSR

Simulation of the SMILE Soft X-ray Imager response to a southward interplanetary magnetic field turning

The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) Soft X-ray Imager (SXI) will shine a spotlight on magnetopause dynamics during magnetic reconnection. We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time. By making assumptions about the magnetopause shape, we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic (MHD) simulation. The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE (Earth radius) and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning

Decision-making capacity for treatment in psychiatric and medical in-patients: Cross-sectional, comparative study

BackgroundIs the nature of decision-making capacity (DMC) for treatment significantly different in medical and psychiatric patients?AimsTo compare the abilities relevant to DMC for treatment in medical and psychiatric patients who are able to communicate a treatment choice.MethodA secondary analysis of two cross-sectional studies of consecutive admissions: 125 to a psychiatric hospital and 164 to a medical hospital. The MacArthur Competence Assessment Tool – Treatment and a clinical interview were used to assess decision-making abilities (understanding, appreciating and reasoning) and judgements of DMC. We limited analysis to patients able to express a choice about treatment and stratified the analysis by low and high understanding ability.ResultsMost people scoring low on understanding were judged to lack DMC and there was no difference by hospital (P=0.14). In both hospitals there were patients who were able to understand yet lacked DMC (39% psychiatric v. 13% medical in-patients, P&lt;0.001). Appreciation was a better ‘test’ of DMC in the psychiatric hospital (where psychotic and severe affective disorders predominated) (P&lt;0.001), whereas reasoning was a better test of DMC in the medical hospital (where cognitive impairment was common) (P=0.02).ConclusionsAmong those with good understanding, the appreciation ability had more salience to DMC for treatment in a psychiatric setting and the reasoning ability had more salience in a medical setting.</jats:sec

Multi-Scale Characterisation for Micro-Architectures

Synthetic and natural micro-architectures (e.g. foams, bone, etc.) are becoming increasingly popular for applications requiring tailored material properties. The method developed by the authors enables the bulk response of large inhomogeneous domains with two distinct length-scales to be obtained through characterisation. The characteristics obtained from the process can also be visualised to highlight the variation of properties. By considering independent sub-volumes the characterisation technique provides a high degree of parallelism and considerably reduced memory requirements

Comparative Analysis and Variability of the Jovian X‐Ray Spectra Detected by the Chandra and XMM‐Newton Observatories

Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X‐ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM‐Newton by systematically varying the initial precipitating ion parameters to obtain the best fit model for the observed spectra. In addition to the oxygen and sulfur ions considered previously, carbon is included to discriminate between solar wind and Jovian magnetospheric ion origins, enabled by the use of extensive databases of both atomic collision cross sections and radiative transitions. On the basis of fits to all the Chandra observations, we find that carbon contributes negligibly to the observed polar X‐ray emission suggesting that the highly accelerated precipitating ions are of magnetospheric origin. Most of the XMM‐Newton fits also favor this conclusion with one exception that implies a possible carbon contribution. Comparison among all the spectra from these two observatories in light of the inferred initial energies and relative abundances of precipitating ions from the modeling show that they are significantly variable in time (observation date) and space (north and south polar X‐ray auroras).Astronom

Simulation of the SMILE Soft X-ray Imager response to a southward interplanetary magnetic field turning

The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) Soft X-ray Imager (SXI) will shine a spotlight on magnetopause dynamics during magnetic reconnection. We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time. By making assumptions about the magnetopause shape, we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic (MHD) simulation. The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE (Earth radius) and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning

BDNF Polymorphism Predicts General Intelligence after Penetrating Traumatic Brain Injury

Neuronal plasticity is a fundamental factor in cognitive outcome following traumatic brain injury. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays an important role in this process. While there are many ways to measure cognitive outcome, general cognitive intelligence is a strong predictor of everyday decision-making, occupational attainment, social mobility and job performance. Thus it is an excellent measure of cognitive outcome following traumatic brain injury (TBI). Although the importance of the single-nucleotide polymorphisms polymorphism on cognitive function has been previously addressed, its role in recovery of general intelligence following TBI is unknown. We genotyped male Caucasian Vietnam combat veterans with focal penetrating TBI (pTBI) (n = 109) and non-head injured controls (n = 38) for 7 BDNF single-nucleotide polymorphisms. Subjects were administrated the Armed Forces Qualification Test (AFQT) at three different time periods: pre-injury on induction into the military, Phase II (10–15 years post-injury, and Phase III (30–35 years post-injury). Two single-nucleotide polymorphisms, rs7124442 and rs1519480, were significantly associated with post-injury recovery of general cognitive intelligence with the most pronounced effect at the Phase II time point, indicating lesion-induced plasticity. The genotypes accounted for 5% of the variance of the AFQT scores, independently of other significant predictors such as pre-injury intelligence and percentage of brain volume loss. These data indicate that genetic variations in BDNF play a significant role in lesion-induced recovery following pTBI. Identifying the underlying mechanism of this brain-derived neurotrophic factor effect could provide insight into an important aspect of post-traumatic cognitive recovery

The Origin of the Cosmic Soft X-Ray Background: Optical Identification of an Extremely Deep ROSAT Survey

We present the results of the deepest optically identified X-ray survey yet made. The X-ray survey was made with the ROSAT PSPC and reaches a flux limit of 1.6x10^-15 erg cm^-2 s^-1 (0.5--2.0 keV). Above a flux limit of 2x10^-15 erg cm^-2 s^-1 we define a complete sample of 70 sources of which 59 are identified. Some (5) other sources have tentative identifications and in a further 4 the X-ray error-boxes are blank to R=23 mag. At the brighter flux levels (>= 10^-14 erg cm^-2 s^-1) we confirm the results of previous less deep X-ray surveys with 84% of the sources begin QSOs. At fainter fluxes, however, the survey is dominated by a population of galaxies with narrow optical emission lines (NELGs). In addition, a number of groups and clusters of galaxies are found at intermediate fluxes. Most of these are poor systems of low X-ray luminosity and are generally found at redshifts of > 0.3. Their numbers are consistent with a zero evolutionary scenario, in contrast to the situation for high luminosity clusters at the same redshift. We discuss the significance of these results to the determination of the cosmic soft X-ray background (XRB) and show that at 2x10^-15 erg cm^-2 s^-1, we have resolved more than 50% of the background. We also briefly consider the probable importance of NELG objects to the residual background and look at some of the properties of these unusual objects.Comment: 28 pages, LaTeX, 17 figures from 32 postscript files. Uses mn.sty and epsf.sty. Accepted by MNRAS. Revised version now contains data table. For more information see http://www.astro.soton.ac.uk/~amn/UKdee

To Be Re-Bitten and to Re-Become: examining repeated embodied acts in ritual performance

Image courtesy of Wellcome Trust: http://catalogue.wellcomelibrary.org/record=b1465534This article will examine the use of repetition through two ritual performance contexts: the rimorso repetition of the ritual of tarantism in Salento, Southern Italy, and the deity yoga practice incorporating mudras, mantras and mandalas found in the Vajrayana tradition of Tibetan Buddhism. The two contexts will offer differing approaches to the practice and experience of repetition, whilst also demonstrating how repeating a movement, sound and image can be used to develop a greater bodymind connection that reinforces a sense of identity, belonging and devotion through the act of repeating. The use of repetition in these two ritual performance contexts will be explored through aspects of Buddhist philosophy, in particular how that repetition can create an altering effect on the ‘self’ of the practitioner through an understanding of the ways in which that ‘self’ is constructed. This will involve examining notions such as anatta (non-self) and the skhandas to show how the practice of repetition is a means to create a transformation of the ‘self’ through the action of repeating. This offers the potential for applying this understanding to actors, both at a somatic level of personal development, and also as a means for ‘be-coming’ a character through repeated actions that can alter the bodymind to align to that of the character. This all examines a paradox inherent in repetition in ritual performance: that it is through the action of repeating the same thing that leads to a process of transformation in the bodymind