On the use of electron-multiplying CCDs for astronomical spectroscopy

Conventional CCD detectors have two major disadvantages: they are slow to read out and they suffer from read noise. These problems combine to make high-speed spectroscopy of faint targets the most demanding of astronomical observations. It is possible to overcome these weaknesses by using electron-multiplying CCDs (EMCCDs). EMCCDs are conventional frame-transfer CCDs, but with an extended serial register containing high-voltage electrodes. An avalanche of secondary electrons is produced as the photon-generated electrons are clocked through this register, resulting in signal amplification that renders the read noise negligible. Using a combination of laboratory measurements with the QUCAM2 EMCCD camera and Monte Carlo modelling, we show that it is possible to significantly increase the signal-to-noise ratio of an observation by using an EMCCD, but only if it is optimised and utilised correctly. We also show that even greater gains are possible through the use of photon counting. We present a recipe for astronomers to follow when setting up a typical EMCCD observation which ensures that maximum signal-to-noise ratio is obtained. We also discuss the benefits that EMCCDs would bring if used with the next generation of extremely large telescopes. Although we mainly consider the spectroscopic use of EMCCDs, our conclusions are equally applicable to imaging.Comment: 18 figures, 3 tables, 18 page

Children’s Film as Design Fiction: Ethics, Data, and Technology in Big Hero 6 and Zootopia

This poster explores how technologies and information are represented in recent children’s cinema, seeing these works as diegetic prototypes. We assert that contemporary “kidult” film can serve as a kind of design fiction to explore the ethical and technical tensions of information systems. This approach is supported through close readings of two Disney films, Big Hero 6 and Zootopia, both of which offer uncritical assessments of data aggregation and use in the effort to resolve a crime-adventure story. We sound a note of caution regarding how these films reinforce contemporary cultural concerns about data, privacy, and role of information in society

Case studies to enhance online student evaluation: Bond University – Surveying students online to improve learning and teaching

One of the most sensible ways of improving learning and teaching is to ask the students for feedback. At the end of each teaching period (i.e. semester or term) all universities and many schools survey their students. Usually these surveys are managed online. Questions ask for student perceptions about teaching, assessment and workload. The survey administrators report four common problems

Bayesian photon counting with electron-multiplying charge coupled devices (EMCCDs)

The EMCCD is a CCD type that delivers fast readout and negligible detector noise, making it an ideal detector for high frame rate applications. Because of the very low detector noise, this detector can potentially count single photons. Considering that an EMCCD has a limited dynamical range and negligible detector noise, one would typically apply an EMCCD in such a way that multiple images of the same object are available, for instance, in so called lucky imaging. The problem of counting photons can then conveniently be viewed as statistical inference of flux or photon rates, based on a stack of images. A simple probabilistic model for the output of an EMCCD is developed. Based on this model and the prior knowledge that photons are Poisson distributed, we derive two methods for estimating the most probable flux per pixel, one based on thresholding, and another based on full Bayesian inference. We find that it is indeed possible to derive such expressions, and tests of these methods show that estimating fluxes with only shot noise is possible, up to fluxes of about one photon per pixel per readout.Comment: Fixed a few typos compared to the published versio

Tight constraints on the existence of additional planets around HD 189733

We report a transit timing study of the transiting exoplanetary system HD 189733. In total we observed ten transits in 2006 and 2008 with the 2.6-m Nordic Optical Telescope, and two transits in 2007 with the 4.2-m William Herschel Telescope. We used Markov-Chain Monte Carlo simulations to derive the system parameters and their uncertainties, and our results are in a good agreement with previously published values. We performed two independent analyses of transit timing residuals to place upper mass limits on putative perturbing planets. The results show no evidence for the presence of planets down to 1 Earth mass near the 1:2 and 2:1 resonance orbits, and planets down to 2.2 Earth masses near the 3:5 and 5:3 resonance orbits with HD 189733b. These are the strongest limits to date on the presence of other planets in this system.Comment: 10 pages, 4 figures, accepted by MNRA

Did the Student Engage in Academic Dishonesty on their Exam? Yes, No, and Shades of Grey in Decision Making

In academia, there are guidelines as to what constitutes academic dishonesty, and how to report it. This leads to the assumption that when instances arise, there are clear yes or no answers to the questions: (a) did the student engage in academic dishonesty, and (b) how should the student be disciplined? Previous research has been conducted examining the behaviours students engage in and the repercussions, but less research has examined the cognitions and actions of the people who discover the instances of academic dishonesty. Therefore, the purpose of this study was to examine how participants make sense of potential academic dishonesty scenarios and the resulting actions they would take. We presented 201 preservice teachers with three scenarios: (a) sneaking answers into an exam, (b) having someone tell you the answers and (c) peeking at someone else’s answers. For each scenario, they had to respond to the items (1) to what extent do you consider the student’s behaviour as academic dishonesty, (2) What in the story helped you decide on your response? and (3) What do you think is an appropriate form of discipline? Overall, participants strongly agreed the behaviours were academically dishonest, however, when asked to indicate what in the story helped them decide, the majority made embellishments to the story, and close to half of the participants provided their opinions related to academic dishonesty more broadly. Moreover, participants indicated a wide range of disciplines for the same scenarios. The results will be utilized to create discussion around decision-making and academic dishonesty

Challenges That Hinder Parturients to Deliver in Health Facilities: a Qualitative Analysis in Two Districts of Indonesia

Background: There are many challenges women face to be able to give birth in health facilities in many parts of Indonesia. This study explores the roles and observations of close-to-community maternal health providers and other community members on potential barriers faced by women to deliver in health facilities in two districts within The Archipelago. Methods: Employing an explorative qualitative approach, 110 semi-structured interviews and 7 focus group discussions were conducted in 8 villages in Southwest Sumba, in the East Nusa Tenggara province, and in 8 villages in Cianjur, in the West Java province. The participants included village midwives, Posyandu volunteer (village health volunteers), traditional birth attendants (TBAs), mothers, men, village heads and district health officials. Results: The main findings were mostly similar in the two study areas. However, there were some key differences. Preference for TBA care, traditional beliefs, a lack of responsiveness of health providers to local traditions, distance, cost of travel and indirect costs of accompanying family members were all barriers to patients attending health facilities for the birth of their child. TBAs were the preferred health providers in most cases due to their close proximity at the time of childbirth and their adherence to traditional practices during pregnancy and delivery. Conclusions: Improving collaborations between midwives and TBAs, collaboration, and responsiveness to traditional practices within health facilities and effective health promotion campaigns about the benefits of giving birth in health facilities may increase the use of health facilities in both study areas.&nbsp

Diversionary feeding: an effective management strategy for conservation conflict?

Human population growth has led to increased contact between people and wildlife, with adverse impacts for both, such as damage to economic crops and wildlife persecution. Diversionary feeding, where food is used to draw animals away from problem activities or locations, is sometimes proposed as a socially acceptable conservation action, but little information exists on its success or what influences its efficacy. Here, we review literature on diversionary feeding and evaluate factors contributing to its success or failure. Success varied greatly among studies and successful uptake of diversionary food did not consistently produce outcomes that met stakeholder objectives. Studies often failed to report results in sufficient detail to allow a quantitative evaluation of efficiency. Of 30 trials presented in 21 studies, 13 enabled assessment of outcomes related to the ultimate objective of reducing conflict (related to threatened prey density, crop yield or nuisance reports) and only five of these were considered successful by the researchers conducting the study. A grand mean increase of 15% in respective measures of success at the outcome stage was found across all studies. Although diversionary feeding is considered expensive, cost-effectiveness analyses were rarely conducted. Only a third of studies reported information on costs and benefits that could be used to inform future management actions. We propose a decision-making framework that incorporates ecological knowledge, financial costs and evidence from previous studies to aid the planning and implementation of diversionary feeding in an adaptive format. Future studies of diversionary feeding should clearly report objectives, results, costsand effort to allow the return-on-investment to be calculated for different levels of management effort

Using routine clinical and administrative data to produce a dataset of attendances at Emergency Departments following self-harm

Background: Self-harm is a significant public health concern in the UK. This is reflected in the recent addition to the English Public Health Outcomes Framework of rates of attendance at Emergency Departments (EDs) following self-harm. However there is currently no source of data to measure this outcome. Routinely available data for inpatient admissions following self-harm miss the majority of cases presenting to services. Methods: Using the Clinical Record Interactive Search system, the electronic health records (EHRs) used in four EDs were linked to Hospital Episode Statistics to create a dataset of attendances following self-harm. This dataset was compared with an audit dataset of ED attendances created by manual searching of ED records. The proportion of total cases detected by each dataset was compared. Results: There were 1932 attendances detected by the EHR dataset and 1906 by the audit. The EHR and audit datasets detected 77 and 76 of all attendances respectively and both detected 82 of individual patients. There were no differences in terms of age, sex, ethnicity or marital status between those detected and those missed using the EHR method. Both datasets revealed more than double the number of self-harm incidents than could be identified from inpatient admission records. Conclusions: It was possible to use routinely collected EHR data to create a dataset of attendances at EDs following self-harm. The dataset detected the same proportion of attendances and individuals as the audit dataset, proved more comprehensive than the use of inpatient admission records, and did not show a systematic bias in those cases it missed. © 2015 Polling et al