Development of a TDC to equip a Liquid Xenon PET prototype

A Time to Digital Converter was designed (CMOS 0.35 $\mum) in order to be used in Liquid Xenon PET prototype. The circuit proved to be able to work at -120 degrees C, while showing a resolution of 250 ps. The circuit enables a low readout dead time (<90 ns) and provides a fully synchronous digital interface for easy data retrieval.Comment: 4 pages, submitted to IEEE Transactions on Nuclear Scienc

Improving the CPI’s Age-Bias Adjustment: Leverage, Disaggregation and Model Averaging

As a rental unit ages, its quality typically falls; a failure to correct for this would result in downward bias in the CPI. We investigate the BLS age bias imputation and explore two potential categories of error: approximations related to the construction of the age bias factor, and model mis-specification. We find that, as long as one stays within the context of the current official regression specification, the approximation errors are innocuous. On the other hand, we find that the official regression specification – which is more or less of the form commonly used in the hedonic rent literature – is severely deficient in its ability to match the conditional log-rent vs. age relationship in the data, and performs poorly in out-of-sample tests. It is straightforward to improve the specification in order to address these deficiencies. However, basing estimates upon a single regression model is risky. Age-bias adjustment inherently suffers from a general problem facing some types of hedonic-based adjustments, which is related to model uncertainty. In particular, age-bias adjustment relies upon specific coefficient estimates, but there is no guarantee that the true marginal influence of a regressor is being estimated in any given model, since one cannot guarantee that the Gauss-Markov conditions hold. To address this problem, we advocate the use of model averaging, which is a method that minimizes downside risks related to model misspecification and generates more reliable coefficient estimates. Thus, after selecting several appropriate models, we estimate age-bias factors by taking a trimmed average over the factors derived from each model. We argue that similar methods may be readily implemented by statistical agencies (even very small ones) with little additional effort. We find that, in 2004 data, BLS age-bias factors were too small, on average, by nearly 40%. Since the age bias term itself is rather small, the implied downward-bias of the aggregate indexes is modest. On the other hand, errors in particular metropolitan areas were much larger, with annual downward-bias as large as 0.6%.Depreciation, Hedonics, Model Averaging, Inflation, CPI Bias

An Asset To Society

The majority of the good American doctors today are in the armed services. These doctors have become accustomed to working together and they have had good equipment. Many of them have closed their offices completely, and a large number of these will have no desire to go to great expense to reopen their offices and buy up-to-date equipment (for that, too, is constantly changing). These men have stated preferences for state medicine or, at least, for group work. If it is what the physicians wish and if it will benefit society as much as I believe it will, state medicine is something which we all must consider a necessary part of our future

What Does it Mean to be an Assistant Principal in Catholic Primary Schools in Western Australia? An Exploratory Instrumental Case Study

This research aimed to explore the role of assistant principal in Catholic primary schools in Western Australia and is the first empirical study of assistant principals in this context. This research was predominantly qualitative and used interpretivism, specifically symbolic interactionism, as its theoretical perspective. An exploratory instrumental case study methodology was used to gain an in-depth understanding of the viewpoints of assistant principals regarding their role. Data collection methods included an online survey and semi-structured interviews as the primary sources, with a document search and researcher field notes adding further information. Miles et al.’s (2020) interactive data management and analysis model was employed for data condensation, data display and to draw and verify conclusions. The review of literature highlighted three themes that formed the conceptual framework for this inquiry and led to the development of five specific research questions. These questions focused on exploring the breadth of the role of assistant principal, the aspects of their work that assistant principals felt were most important, their sources of professional fulfilment and challenge and how the Catholic education system of Western Australia could best support them in their work. The research suggested that assistant principals in Catholic primary schools in Western Australia undertake a wide range of tasks. They are generally satisfied in their work and derive professional fulfilment from many aspects of their role. However, assistant principals also experience challenges in their work, primarily due to their expanding workload and lack of time to complete their tasks. Concerns were raised about the sustainability of the role in its present form due to the negative impact on the wellbeing of assistant principals. Assistant principals also felt conflict between their administrative and leadership responsibilities. As a result of this research, a framework summarising the leadership of assistant principals in Catholic primary schools in Western Australia was proposed. The model highlights their servant, instructional and transactional leadership, as well as their contribution to the Catholic identity of schools. The research culminated in recommendations for the role of assistant principal in Catholic primary schools in Western Australia, several suggestions for further research and the identification of additions to the body of published literature relating to the role of assistant principal

Dialogic learning: from an educational concept to daily classroom teaching

This article presents the genesis and the main elements that compose the cycle of the dialogic learning. The development of the concept of self-controlled and sustainable learning is based on a personal encounter between two teachers of entirely different subjects: Mathematics and German. Two examples show how uncomplicated teaching mathematics in the classroom can be, once the teacher has gained the courage to trust in the capabilities of the children. The three German textbooks “Ich-Du-Wir” (“I-You-We”) for mother tongue and mathematics in the first six years of elementary school provide support