An Injection-locked Diode Laser for Cold Rydberg Atom Experiments

A free-running, temperature stabilized diode laser has been injection-locked to an external cavity diode laser for use in cold Rydberg atom experiments. Cold rubidium atoms in a magneto-optical trap (MOT) are excited to Rydberg states using a 10 ns laser pulse. The Rydberg atoms spontaneously ionize due to dipole forces, and the collisional ionization dynamics are observed as a function of atom density and principal quantum number of the Rydberg state, n. The injection-locked diode laser will be used as a repumper in conjunction with a dark spontaneous-force optical trap (SPOT) to increase the Rydberg state density. We report on the design of the injection-locked laser system.

Cost-effectiveness analysis of screening for lung cancer with low dose spiral CT (computed tomography) in the Australian setting

Introduction:
Low dose spiral computed tomography (CT) is a sensitive screening tool for lung cancer that is currently being evaluated in both non-randomised studies and randomised controlled trials.
Methods:
We conducted a quantitative decision analysis using a Markov model to determine whether, in the Australian setting, offering spiral CT screening for lung cancer to high risk individuals would be cost-effective compared with current practice. This exploratory analysis was undertaken predominantly from the perspective of the government as third-party funder. In the base-case analysis, the costs and health outcomes (life-years saved and quality-adjusted life years) were calculated in a hypothetical cohort of 10,000 male current smokers for two alternatives: (1) screen for lung cancer with annual CT for 5 years starting at age 60 year and treat those diagnosed with cancer or (2) no screening and treat only those who present with symptomatic cancer.
Results:
For male smokers aged 60–64 years, with an annual incidence of lung cancer of 552 per 100,000, the incremental cost-effectiveness ratio was $57,325 per life-year saved and $105,090 per QALY saved. For females aged 60–64 years with the same annual incidence of lung cancer, the cost-effectiveness ratio was $51,001 per life-year saved and $88,583 per QALY saved. The model was used to examine the relationship between efficacy in terms of the expected reduction in lung cancer mortality at 7 years and cost-effectiveness. In the base-case analysis lung cancer mortality was reduced by 27% and all cause mortality by 2.1%. Changes in the estimated proportion of stage I cancers detected by screening had the greatest impact on the efficacy of the intervention and the cost-effectiveness. The results were also sensitive to assumptions about the test performance characteristics of CT scanning, the proportion of lung cancer cases overdiagnosed by screening, intervention rates for benign disease, the discount rate, the cost of CT, the quality of life in individuals with early stage screen-detected cancer and disutility associated with false positive diagnoses. Given current knowledge and practice, even under favourable assumptions, reductions in lung cancer mortality of less than 20% are unlikely to be cost-effective, using a value of $50,000 per life-year saved as the threshold to define a “cost-effective” intervention.
Conclusion:
The most feasible scenario under which CT screening for lung cancer could be cost-effective would be if very high-risk individuals are targeted and screening is either highly effective or CT screening costs fall substantially.

Peripheral quantitative computed tomography in children and adolescents : the 2007 ISCD pediatric official positions

Peripheral quantitative computed tomography (pQCT) has mainly been used as a research tool in children. To evaluate the clinical utility of pQCT and formulate recommendations for its use in children, the International Society
of Clinical Densitometry (ISCD) convened a task force to review the literature and propose areas of consensus and future research. The types of pQCT technology available, the clinical application of pQCT for bone health assessment in children, the important elements to be included in a pQCT report, and quality control monitoring techniques were evaluated. The review revealed a lack of standardization of pQCT techniques, and a paucity of data regarding differences between pQCT manufacturers, models and software versions and their impact in pediatric assessment. Measurement sites varied across studies. Adequate reference data, a critical element for interpretation of pQCT results, were entirely lacking, although some comparative data on healthy children were available. The elements of the
pQCT clinical report and quality control procedures are similar to those recommended for dual-energy X-ray absorptiometry. Future research is needed to establish evidence-based criteria for the selection of the measurement site, scan acquisition and analysis parameters, and outcome measures. Reference data that sufficiently characterize the normal range of variability in the population also need to be established.

3-dimensional characterization of membrane with nanoporous structure using TEM tomography and image analysis

The nanoporous structure of membrane varies in 3-dimensional (3-D) space and has remarkable influences on the filtration or desalination achieved, fouling potentials and therefore, the quality of yielded water. Knowledge of the 3-D nanoporous structure is thus vital to understanding and predicting its performance. A novel method by incorporating transmission electronic microtomography, image processing and 3-D reconstruction is introduced to characterize membranes with nano structures. The reconstruction algorithm allows for the visualization of 3-D nanoporous structure in a non-destructive way from any directions. This novel technique Ieads to in-depth understanding and accurate prediction of filtration performance.

Refractive index tomography of turbid media by bifocal optical coherence refractometry

We demonstrate tomographic imaging of the refractive index of turbid media using bifocal optical coherence refractometry (BOCR). The technique, which is a variant of optical coherence tomography, is based on the measurement of the optical pathlength difference between two foci simultaneously present in a medium of interest. We describe a new method to axially shift the bifocal optical pathlength that avoids the need to physically relocate the objective lens or the sample during an axial scan, and present an experimental realization based on an adaptive liquid-crystal lens. We present experimental results, including video clips, which demonstrate refractive index tomography of a range of turbid liquid phantoms, as well as of human skin in vivo.

3-dimensional characterization of membrane with nanoporous structure using TEM tomography and image analysis

The nanoporous structure of a membrane varies in a 3-dimensional (3-D) space and has remarkable influences on the filtration or desalination achieved, fouling potentials and therefore, the quality of yielded water. Knowledge of the 3-D nanoporous structure is thus vital to understanding and predicting its performance. A novel method by incorporating transmission electronic microtomography, image processing and 3-D reconstruction is introduced to characterize membranes with nano structures. The reconstruction algorithm allows for the visualization of 3-D nanoporous structure in a non-destructive way from any directions. This novel technique leads to in-depth understanding and accurate prediction of filtration performance.

Emotional habituation to filmed violence employing the startle probe response

This thesis reports on research examining the habituation of emotional variables to filmed violence. The following subjective emotional variables were assessed: positive feelings, anxiety, disgust, entertainment and anger. In addition, an objective measure of emotional response was recorded physiologically, using the startle eyeblink response. The mediating influence of personality, individual differences and contextual features on an individuals’ perception of and reaction to filmed violence were also explored. Study one was exploratory in nature served to identify and select the film stimuli to be employed in the subsequent studies. The primary aim of the study was to allow for the identification of violent stimuli considered to be most socially and culturally relevant. The present research builds on existing scientific literature which has began to appreciate that differences in the context of a portrayal holds important implications for its impact on viewers. Thus, a secondary and more specific desire of study one was to obtain an evaluation of the contextual features of the violent film segments. A sample of 30 participants viewed and rated the film stimuli on the variables of realism, fantasy and violence. From this exploratory study four violent film stimuli were subsequently employed. Study 2 used the eyeblink startle response proposed by Vrana, Spence and Lang (1988) to explore the habituation of emotional variables to a realistic depiction of filmed violence. Emotional response was assessed both objectively, using the eyeblink startle response and subjectively through individuals self-reports. In addition the study investigated the significance of individual differences as mediators of emotional response. Questionnaire and physiological data were obtained from 30 participants. Overall, repeated exposure to filmed violence resulted in a decline in both objective and subjective emotional response. Differences were identified in the manner in which men and women responded to the film. Women reacted initially and over time with more intense physiological and psychological reactions to the violent film than males. Specifically, men displayed more curiosity and reported greater entertainment and positive feelings in response to the film, whilst women found the violence more disgusting and reported higher levels of anger and anxiety. It was found that the eyeblink startle magnitude paralleled the subjective emotional processing of the violent film, thus providing further confirmatory evidence of its validity in the investigation of emotional reactions to a stimulus. Personality factors were found to mediate emotional response to filmed violence, with neuroticism most powerfully implicated. High levels of neuroticism were found to be associated with greater anger and anxiety and less positive feelings whilst viewing violent film. A high score on extraversion was correlated with higher levels of anger and lower levels of curiosity and entertainment. Whilst the aims of study 3 were identical to that of study 2, a variation in the contextual feature of the violent film stimuli under investigation was the distinguishing and pertinent feature. Study 2 provided data on the habituation of emotional response to a realistic depiction of filmed violence. Study 3 was concerned with emotional response over repeated exposure to a fantasized violent depiction. Therefore, allowing for a comparison regarding the effects of context on emotional response. The results of study 3, with respect to habituation of emotional response, personality and individual differences, were similar to that obtained in study 2. A comparison of the two studies, however, revealed that individuals responded significantly different to the contextual features of the violent portrayal. Compared to the fantasised portrayal the realistic film stimulus was reported to be more digusting, anxiety provoking and less entertaining. In addition, and not surprisingly respondents reported that the realistic portrayal resulted in the production of more anger and less positive feelings.

Cycles of genocide, stories of denial : Atom Egoyan's Ararat

This article focuses on Atom Egoyan's Ararat and explores how, through a convoluted narrative structure, Egoyan grapples with denial of the Armenian Genocide and the consequences of those denials for present generations—both Turkish and Armenian—illuminated in the film as an extension of the genocide. Egoyan uses a film-within-a-film to move beyond a popular definition of genocide as mass killing alone and links the understanding of stories, truths, and perspectives in everyday life to the dehumanizing acts of genocide. Employing the philosopher Emmanuel Levinas’ ethical theory of the Other (the ethical) and philosophical understandings of ontology (dehumanization) to illuminate the genocide and its ongoing denial, this article contends that Egoyan's focus on the generations of genocide survivors points to the ethical responsibility to one another that underlies everyday lives and sits at the heart of what is absent in the acts of genocide.

Concept design of a novel tactile probe tip for down scaled 3D CMMs

Although coordinate metrology has reached a very high state of development concerning versatility and accuracy for common engineering parts, a high precision capability with nano scale resolution and accuracy is often hard to achieve when it is required to measure very small parts and features. The limiting component is the bulky probing system of traditional CMMs (coordinate measuring machines). In order to satisfy increasing demand for highly accurate geometrical measurements on small parts and small structures, a new measuring probe of high sensitivity and small geometrical dimension with low contact forces needs to be developed. In this paper, a novel probing system, which combines a FBG (Fibre Bragg Grating) embedded optical fibre tactile probe with an optical sensing technique, has been proposed. With the sensor elements integrated into the probe tip directly, the system sensitivity can be increased significantly. A preliminary theoretical analysis of the sensitivity of the FBG fibre sensor under axial and lateral end point loading has been presented and the results show that this micro scale probe has great potential to realize a resolution of 1nanometer on geometrical measurement of small parts.

Automatic detection of lung nodule from computer tomography images

Lung nodule refers to lung tissue abnormalities that may become cancerous. An automated system that detects nodules of common sizes within lung images is developed. It consists of acquisition, pre-processing, background removal, nodule detection, and false positives reduction. The system can assist expert radiologists in their decision making.