396 research outputs found
Verifying timestamps of occultation observation systems
We describe an image timestamp verification system to determine the exposure
timing characteristics and continuity of images made by an imaging camera and
recorder, with reference to Coordinated Universal Time (UTC). The original use
was to verify the timestamps of stellar occultation recording systems, but the
system is applicable to lunar flashes, planetary transits, sprite recording, or
any area where reliable timestamps are required. The system offers good
temporal resolution (down to 2 msec, referred to UTC) and provides exposure
duration and interframe dead time information. The system uses inexpensive,
off-the- shelf components, requires minimal assembly and requires no
high-voltage components or connections. We also describe an application to load
FITS (and other format) image files, which can decode the verification image
timestamp. Source code, wiring diagrams and built applications are provided to
aid the construction and use of the device.Comment: 10 pages, 7 figures, accepted to Publications of the Astronomical
Society of Australia (PASA
Differentiable Programming for Earth System Modeling
Earth System Models (ESMs) are the primary tools for investigating future
Earth system states at time scales from decades to centuries, especially in
response to anthropogenic greenhouse gas release. State-of-the-art ESMs can
reproduce the observational global mean temperature anomalies of the last 150
years. Nevertheless, ESMs need further improvements, most importantly regarding
(i) the large spread in their estimates of climate sensitivity, i.e., the
temperature response to increases in atmospheric greenhouse gases, (ii) the
modeled spatial patterns of key variables such as temperature and
precipitation, (iii) their representation of extreme weather events, and (iv)
their representation of multistable Earth system components and their ability
to predict associated abrupt transitions. Here, we argue that making ESMs
automatically differentiable has huge potential to advance ESMs, especially
with respect to these key shortcomings. First, automatic differentiability
would allow objective calibration of ESMs, i.e., the selection of optimal
values with respect to a cost function for a large number of free parameters,
which are currently tuned mostly manually. Second, recent advances in Machine
Learning (ML) and in the amount, accuracy, and resolution of observational data
promise to be helpful with at least some of the above aspects because ML may be
used to incorporate additional information from observations into ESMs.
Automatic differentiability is an essential ingredient in the construction of
such hybrid models, combining process-based ESMs with ML components. We
document recent work showcasing the potential of automatic differentiation for
a new generation of substantially improved, data-informed ESMs.Comment: 17 pages, 2 figure
Stabilized Neural Differential Equations for Learning Dynamics with Explicit Constraints
Many successful methods to learn dynamical systems from data have recently
been introduced. However, ensuring that the inferred dynamics preserve known
constraints, such as conservation laws or restrictions on the allowed system
states, remains challenging. We propose stabilized neural differential
equations (SNDEs), a method to enforce arbitrary manifold constraints for
neural differential equations. Our approach is based on a stabilization term
that, when added to the original dynamics, renders the constraint manifold
provably asymptotically stable. Due to its simplicity, our method is compatible
with all common neural differential equation (NDE) models and broadly
applicable. In extensive empirical evaluations, we demonstrate that SNDEs
outperform existing methods while broadening the types of constraints that can
be incorporated into NDE training.Comment: 22 pages, 8 figures. Accepted at NeurIPS 202
Integrating quantitative and qualitative data in assessing the cost-effectiveness of biodiversity conservation programmes
Globally, most biodiversity conservation programmes are not currently evaluated in terms of their costs and benefits, or their rate of return on the original investment. Assessing the cost-effectiveness of such schemes is challenging as the relationship between spending and the effectiveness of conservation is dependent on many biological and socio-economic factors. Here, we evaluate the cost-effectiveness of a selection of species and habitat conservation schemes undertaken through the Scotland Rural Development Programme. We use a combination of quantitative and qualitative data, based on expert knowledge, to estimate effectiveness and cost-effectiveness of different schemes and understand variations in the results. Our findings highlight a lack of geographical targeting in terms of where the funding might achieve the most conservation benefit, which may be contributing to high costs per unit of effectiveness. Recommendations include the need for improved advice on appropriate management and monitoring programmes that are linked closely to objectives. Conservation schemes within Scotland were used as the focus of the study, but the approaches used, interpretations drawn and improvements identified could be applied to any regional, national or international biodiversity conservation programmes. Cost and effectiveness data can be subject to a high degree of uncertainty and hence any cost-effectiveness estimate is subject to a number of caveats. There is therefore a need to focus not only on improving the cost-effectiveness of biodiversity conservation programmes, but also to improve the robustness of cost-effectiveness assessments, in terms of data availability and accuracy and improved monitoring of the outcomes of interventions
Baywide anchovy study sub-program : milestone report no. 4 (2011)
ii If you would like to receive this information/publication in an accessible format (such as large print or audio) please call the Customer Service Centre on
Prepared to teach : an investigation into the preparation of teachers to teach literacy and numeracy
Teacher education in Australia is a large and diverse enterprise. There are more than 400 programs in 36 universities, enrolling a total of about 35,000 preservice teachers (DEST, 2003).
The labour market for newly graduating teachers, pattern of entry to teacher education, the range of courses offered, the place of literacy and numeracy in those courses, and the provision of school experience influence the quality of beginning teachers\u27 literacy and numeracy teaching
Depression and anxiety in adolescents and adults with cystic fibrosis in the UK: A cross-sectional study
Background
The International Depression/anxiety Epidemiological Study (TIDES) in the UK aimed: (i) to establish the prevalence of anxiety and depression amongst people with CF compared to a normative sample; (ii) to establish the association between mood, demographic and clinical variables; and (iii) to provide guidance for specialist-referral decision-making.
Methods
Patients (≥ 12 years) completed the Hospital Anxiety and Depression Scale (HADS). CF-HADS scores, expressed as percentiles, were compared with a normative sample. Multiple-regression analysis explored associations between demographic, clinical and mood variables.
Results
Thirty-nine CF centres recruited 2065 patients. Adults with CF were similar in terms of anxiety and depression to the general population. Adolescents with CF were less anxious and depressed. For adult patients, older age, unemployment for health reasons and poor lung function were associated with disordered mood. Gender-specific CF-percentile scores were calculated.
Conclusion
Surveillance, with attention to gender and risk factors is advocated. This work provides unique benchmark scores to aid referral decision-making
- …