Combining Open and Financial Data for Targeted Policy Solutions

Join Mike Spencer from Smart Data Foundry as he introduces a case study of open data in action

Order estimation and discrimination between stationary and time-varying (TVAR) autoregressive models

Copyright © 2007 IEEEFor a set of T independent observations of the same N-variate correlated Gaussian process, we derive a method of estimating the order of an autoregressive (AR) model of this process, regardless of its stationary or time-varying nature. We also derive a test to discriminate between stationary AR models of order m,AR(m), and time-varying autoregressive models of order m,TVAR(m). We demonstrate that within this technique the number T of independent identically distributed data samples required for order estimation and discrimination just exceeds the maximum possible order mmax, which in many cases is significantly fewer than the dimension of the problem NYuri I. Abramovich, Nicholas K. Spencer, and Michael D. E. Turle

Time-varying autoregressive (TVAR) models for multiple radar observations

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.We consider the adaptive radar problem where the properties of the (nonstationary) clutter signals can be estimated using multiple observations of radar returns from a number of sufficiently homogeneous range/azimuth resolution cells. We derive a method for approximating an arbitrary Hermitian covariance matrix by a time-varying autoregressive model of order m, TVAR(m), that is based on the Dym-Gohberg band-matrix extension technique which gives the unique TVAR(m) model for any nondegenerate covariance matrix. We demonstrate that the Dym-Gohberg transformation of the sample covariance matrix gives the maximum-likelihood (ML) estimate of the TVAR(m) covariance matrix. We introduce an example of TVAR(m) clutter modeling for high-frequency over-the-horizon radar that demonstrates its practical importanceYuri I. Abramovich, Nicholas K. Spencer, and Michael D. E. Turle

Grand County Agriculture Profile

This publication includes a report that gives agricultural facts and statistics pertaining to Grand County

Defining mangrove-fisheries: A typology from the Perancak Estuary, Bali, Indonesia.

This study develops a definition of what mangrove-fisheries can encompass, incorporating a broad range of their possible characteristics. A detailed case study was conducted to develop a typology of mangrove-fishing in the Perancak Estuary, Bali, Indonesia, using interview surveys to investigate the fishing activities associated with mangroves. This case study demonstrated the complexity that a mangrove-fishery can entail, where fishing is connected to the mangrove forest by fishers of multiple sectors, functions, locations and temporal scales. Through a comparison with other mangrove-fishing communities in Bali, it also highlighted that mangrove-fisheries are variable even when in close proximity. With particular reference to this case study, a framework was developed as a flexible tool for identifying the multiple dimensions of a mangrove-fishery in a local context. Following this framework should encourage researchers and managers to look outside of the groups of fishers traditionally expected to benefit from mangrove fishing. This will enable the development of a broader definition of mangrove-fisheries in a site specific way. Identifying the full scope of fishers that contribute to or benefit from a mangrove-fishery is the first step towards building management measures that reflect the interests of groups of fishers that may otherwise remain under-represented. This is in line with international efforts for sustainability, especially in promoting small-scale fishers' access to sustainable resources under the UN Sustainable Development Goals

The presence of psychological trauma symptoms in resuscitation providers and an exploration of debriefing practices

Introduction Witnessing traumatic experiences can cause post-traumatic stress disorder (PTSD). The true impact on healthcare staff of attending in-hospital cardiac arrests (IHCAs) has not been studied. This cross-sectional study examined cardiac arrest debriefing practices and the burden of attending IHCAs on nursing and medical staff. Methods A 33-item questionnaire-survey was sent to 517 doctors (of all grades), nurses and health-care assistants (HCAs) working in the emergency department, the acute medical unit and the intensive care unit of a district general hospital between April and August 2018. There were three sections: demographics; cardiac arrest and debriefing practices; trauma-screening questionnaire (TSQ). Results The response rate was 414/517 (80.1%); 312/414 (75.4%) were involved with IHCAs. Out of 1463 arrests, 258 (17.6%) were debriefed. Twenty-nine of 302 (9.6%) staff screened positively for PTSD. Healthcare assistants and Foundation Year 1 doctors had higher TSQ scores than nurses or more senior doctors (p = 0.02, p = 0.02, respectively). Debriefing was not associated with PTSD risk (p = 0.98). Only 8/67 (11.9%) of resuscitation leaders had prior debriefing training. Conclusions Nearly 10% of acute care staff screened positively for PTSD as a result of attending an IHCA, with junior staff being most at risk of developing trauma symptoms. Very few debriefs occurred, possibly because of a lack of debrief training amongst cardiac arrest team leaders. More support is required for acute care nursing and medical staff following an IHCA

Benchmarking multi-rate codon models

CITATION: Delport, W. et al. 2010. Benchmarking multi-rate codon models. PLoS ONE, 5(7): e11587, doi:10.1371/journal.pone.0011587.The original publication is available at http://journals.plos.org/plosoneThe single rate codon model of non-synonymous substitution is ubiquitous in phylogenetic modeling. Indeed, the use of a non-synonymous to synonymous substitution rate ratio parameter has facilitated the interpretation of selection pressure on genomes. Although the single rate model has achieved wide acceptance, we argue that the assumption of a single rate of non-synonymous substitution is biologically unreasonable, given observed differences in substitution rates evident from empirical amino acid models. Some have attempted to incorporate amino acid substitution biases into models of codon evolution and have shown improved model performance versus the single rate model. Here, we show that the single rate model of non-synonymous substitution is easily outperformed by a model with multiple non-synonymous rate classes, yet in which amino acid substitution pairs are assigned randomly to these classes. We argue that, since the single rate model is so easy to improve upon, new codon models should not be validated entirely on the basis of improved model fit over this model. Rather, we should strive to both improve on the single rate model and to approximate the general time-reversible model of codon substitution, with as few parameters as possible, so as to reduce model over-fitting. We hint at how this can be achieved with a Genetic Algorithm approach in which rate classes are assigned on the basis of sequence information content. © 2010 Delport et al.http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011587Publisher's versio

Modelling the Transition from Secondary to Tertiary Mathematics Education: Teacher and Lecturer Perspectives

The transition from school to tertiary study of mathematics is rightly coming under increasing scrutiny in research. This paper employs Tall’s model of the three worlds of mathematical thinking to examine key variables in teaching and learning as they relate to this transition. One key variable in the transition is clearly the teacher/lecturer and we consider the perspectives of both teachers and lecturers on teaching related matters relevant to upper secondary and first year tertiary calculus students. While this paper deals with a small part of the data from the project, which aims to model the transition, the results provide evidence of similarities and differences in the thinking of teachers and lecturers about the transition process. They also show that each group lacks a clear understanding of the issues involved in the transition from the other’s perspective, and there is a great need for improved communication between the two sectors