Introduction to Principal Components Analysis

Understanding the inverse equivalent width - luminosity relationship (Baldwin Effect), the topic of this meeting, requires extracting information on continuum and emission line parameters from samples of AGN. We wish to discover whether, and how, different subsets of measured parameters may correlate with each other. This general problem is the domain of Principal Components Analysis (PCA). We discuss the purpose, principles, and the interpretation of PCA, using some examples from QSO spectroscopy. The hope is that identification of relationships among subsets of correlated variables may lead to new physical insight.Comment: Invited review to appear in ``Quasars and Cosmology'', A.S.P. Conference Series 1999. eds. G. J. Ferland, J. A. Baldwin, (San Francisco: ASP). 10 pages, 2 figure

Message Prioritization In Computer-mediated Communication: A Study Of Mobile Device Use In The Classroom

College students are using their mobile devices during class and this research investigates different aspects of why college students feel so inclined to use these devices during class as well as by what means are students using to participate in computer-mediated communication while simultaneously engaging in classes. This research surveyed 146 students on their perceived use of their own mobile device use during class. The study compared how often different types of devices, such as mobile phones, tablets, and laptops, and different types of social media outlets, like Facebook, Twitter, and other social media websites, were used during class. The study compares these devices and media outlets to students’ perception of the levels of incivility of using these various means of communication during class and their perceptions of how they impact their ability to focus on the class. Mobile phones, Facebook, and Twitter use were negatively associated with the perception of the incivility of use in the classroom. This research found phone use was viewed as more uncivil than tablets and tablet use was viewed as more uncivil than laptop use. In addition, students’ perceptions of instructors’ tolerance of mobile phone and laptop use was negatively associated with their perception of the incivility of using those devices during class. All three tested mobile devices and all three tested social media outlets were positively associated with students’ perception that its use affects their ability to focus on the class. This research found mobile phones use as more distracting than laptops and laptops use as more distracting than tablets

A pilot randomised controlled trial of an internet-based cognitive behavioural therapy self-management programme (MS Invigor8) for multiple sclerosis fatigue

The majority of people affected by Multiple Sclerosis (PaMS) experience severe and disabling fatigue. MS Fatigue is poorly understood and most existing treatments have limited effectiveness. However, a recent randomised controlled trial (RCT) showed that cognitive-behaviour therapy with a clinical psychologist was effective in reducing MS fatigue severity and impact. The current study developed an Internet-based version of this intervention to make it available to a wider group of PaMS and conducted preliminary investigations of its efficacy, feasibility and cost-effectiveness in a pilot RCT. The ‘MS Invigor8’ website was developed using agile design and substantial input from PaMS. The programme includes eight online tailored and interactive sessions along with homework tasks, intended to be accessed weekly. In the pilot trial, 40 patients were randomised to MS Invigor8 (n=23) or standard care (n=17). The MS Invigor8 group accessed sessions over 8-10 weeks and received up to three 30-50 minute telephone support sessions. Participants completed online questionnaires assessing fatigue, mood and quality of life at baseline and 10 weeks follow-up. Large between group treatment effects were found for the primary outcomes of fatigue severity (d=1.19) and impact (d =1.22). The MS Invigor8 group also reported significantly greater improvements in anxiety and depression. Analysis suggested that the intervention may be cost-effective. Qualitative feedback suggested that participants considered this treatment approach acceptable and helpful. Technical website problems negatively affected some users’ experiences and need to be resolved. Given the promising results a larger RCT with longer term follow-up is warranted. <br/

A cost benefit analysis of vocational rehabilitation services provided by CRS Australia

This paper analyses the costs and benefits of participation in vocational rehabilitation programs provided by CRS Australia, an Australian Government business unit . It presents estimates of cost data from CRS Australia databases and an analysis of benefits data on employment participation and the reduction in the receipt of Australian government benefits from surveys of CRS Australia clients. Non-participants who did not enter a CRS Australia program following an initial assessment interview were also examined to obtain a control group against which the outcomes from participation in CRS Australia programs can be measured

Empirical comparison of genotoxic potency estimations: the in vitro DNA-damage ToxTracker endpoints versus the in vivo micronucleus assay

Genetic toxicology is an essential component of compound safety assessment. In the face of a barrage of new compounds, higher throughput, less ethically divisive in vitro approaches capable of effective, human-relevant hazard identification and prioritisation are increasingly important. One such approach is the ToxTracker assay, which utilises murine stem cell lines equipped with green fluorescent protein (GFP)-reporter gene constructs that each inform on distinct aspects of cellular perturbation. Encouragingly, ToxTracker has shown improved sensitivity and specificity for the detection of known in vivo genotoxicants when compared to existing ‘standard battery’ in vitro tests. At the current time however, quantitative genotoxic potency correlations between ToxTracker and well-recognised in vivo tests are not yet available. Here we use dose–response data from the three DNA-damage-focused ToxTracker endpoints and from the in vivo micronucleus assay to carry out quantitative, genotoxic potency estimations for a range of aromatic amine and alkylating agents using the benchmark dose (BMD) approach. This strategy, using both the exponential and the Hill BMD model families, was found to produce robust, visually intuitive and similarly ordered genotoxic potency rankings for 17 compounds across the BSCL2-GFP, RTKN-GFP and BTG2-GFP ToxTracker endpoints. Eleven compounds were similarly assessed using data from the in vivo micronucleus assay. Cross-systems genotoxic potency correlations for the eight matched compounds demonstrated in vitro–in vivo correlation, albeit with marked scatter across compounds. No evidence for distinct differences in the sensitivity of the three ToxTracker endpoints was found. The presented analyses show that quantitative potency determinations from in vitro data enable more than just qualitative screening and hazard identification in genetic toxicology

Use of Ultrasound Imaging to Determine Sex of Shovelnose Sturgeon

During November 2002, 51 shovelnose sturgeon Scaphirhynchus platorynchus were sexed by ultrasound imaging using a portable ultrasonograph. We identified males with 96% accuracy (N = 25) and females with 80% accuracy (N = 25); one hermaphroditic individual was misidentified as a male. Overall, ultrasound imaging was 86% accurate. Sex in postspawned females was difficult to determine, 60% being misidentified as males (N = 5). Ultrasonography is an effective noninvasive method for sex determination that can be applied to other species of Acipenseriformes. Modern portable equipment expands its utility to field studies