Incorporating scale dependence in disease burden estimates:the case of human African trypanosomiasis in Uganda

The WHO has established the disability-adjusted life year (DALY) as a metric for measuring the burden of human disease and injury globally. However, most DALY estimates have been calculated as national totals. We mapped spatial variation in the burden of human African trypanosomiasis (HAT) in Uganda for the years 2000-2009. This represents the first geographically delimited estimation of HAT disease burden at the sub-country scale.Disability-adjusted life-year (DALY) totals for HAT were estimated based on modelled age and mortality distributions, mapped using Geographic Information Systems (GIS) software, and summarised by parish and district. While the national total burden of HAT is low relative to other conditions, high-impact districts in Uganda had DALY rates comparable to the national burden rates for major infectious diseases. The calculated average national DALY rate for 2000-2009 was 486.3 DALYs/100 000 persons/year, whereas three districts afflicted by rhodesiense HAT in southeastern Uganda had burden rates above 5000 DALYs/100 000 persons/year, comparable to national GBD 2004 average burden rates for malaria and HIV/AIDS.These results provide updated and improved estimates of HAT burden across Uganda, taking into account sensitivity to under-reporting. Our results highlight the critical importance of spatial scale in disease burden analyses. National aggregations of disease burden have resulted in an implied bias against highly focal diseases for which geographically targeted interventions may be feasible and cost-effective. This has significant implications for the use of DALY estimates to prioritize disease interventions and inform cost-benefit analyses

QALYs, Person Trade-Offs, and the Pareto Principle.

A considerable literature seems to argue the use of person trade-offs to estimate the quality-adjustment factor in Quality-Adjusted Life Years (QALY) models. A similar practise is followed by the WHO to estimate the disability weights used in calculation of Disability-Adjusted Life Years (DALY) for assessment of region- and disease-specific burden of disease. In this note we show that QALY (and DALY) models based on person trade-off scores generally violate the Pareto principle.person trade-off; QALY; DALY; Pareto principle; social welfare

We’re So Bored With London, Wayne Daly in conversation with Russell Bestley, Parts 1 & 2

Interview discussion with Wayne Daly on the subject of UK punk singles

The Masterwork of the Cheese Orpheus

500 word story commissioned by Jeremy Akerman and Eileen Daly for their 'Flash500' online project of 32 artists' stories

Hierarchical elimination-by-aspects and nested logit models of stated preferences for alternative fuel vehicles

1. INTRODUCTION Since the late 1960s, transport demand analysis has been the context for significant developments in model forms for the representation of discrete choice behaviour. Such developments have adhered almost exclusively to the behavioural paradigm of Random Utility Maximisation (RUM), first proposed by Marschak (1960) and Block and Marschak (1960). A common argument for the allegiance to RUM is that it ensures consistency with the fundamental axioms of microeconomic consumer theory and, it follows, permits interface between the demand model and the concepts of welfare economics (e.g. Koppelman and Wen, 2001). The desire to better represent observed choice, which has driven developments in RUM models, has been somewhat at odds, however, with the frequent assault on the utility maximisation paradigm, and by implication RUM, from a range of literatures. This critique has challenged the empirical validity of the fundamental axioms (e.g. Kahneman and Tversky, 2000; Mclntosh and Ryan, 2002; Saelensmide, 1999) and, more generally, the realism of the notion of instrumental rationality inherent in utility maximisation (e.g. Hargreaves-Heap, 1992; McFadden, 1999; Camerer, 1998). Emanating from these literatures has been an alternative family of so-called non-RUM models, which seek to offer greater realism in the representation of how individuals actually process choice tasks. The workshop on Methodological Developments at the 2000 Conference of the International Association for Travel Behaviour Research concluded: 'Non-RUM models deserve to be evaluated side-by-side with RUM models to determine their practicality, ability to describe behaviour, and usefulness for transportation policy. The research agenda should include tests of these models' (Bolduc and McFadden, 2001 p326). The present paper, together with a companion paper, Batley and Daly (2003), offer a timely contribution to this research priority. Batley and Daly (2003) present a detailed account of the theoretical derivation of RUM, and consider the relationships of two specific RUM forms; nested logit [NL] (Ben-Akiva, 1974; Williams, 1977; Daly and Zachary, 1976; McFadden, 1978) and recursive nested extreme value [RNEV] (Daly, 2001 ; Bierlaire, 2002; Daly and Bierlaire, 2003); to two specific non-RUM forms; elimination-by-aspects [EBA] (Tversky, 1972a, 1972b) and hierarchical EBA [HEBA] (Tversky and Sattath, 1979). In particular, Batley and Daly (2003) establish conditions under which NL and RNEV derive equivalent choice probabilities to HEBA and EBA, respectively. These findings would seem to ameliorate the concern that the application of RUM models to data generated by non-RUM choice processes could introduce significant biases. That aside, substantive issues remain as to how non-RUM models can best be specified so as to yield useful and robust information in both estimation and forecasting contexts, and how their empirical performance compares with RUM models. Such issues are the focus of the present paper, which applies non-RUM models to a real empirical context

Cost-effectiveness of voluntary HIV-1 counseling and testing in reducing sexual transmission of HIV-1 in Kenya and Tanzania.

Background Access to HIV-1 voluntary counseling and testing (VCT) is severely limited in less-developed countries. We undertook a multisite trial of HIV-1 VCT to assess its impact, cost, and cost-effectiveness in less-developed country settings.\ud Methods\ud The cost-effectiveness of HIV-1 VCT was estimated for a hypothetical cohort of 10 000 people seeking VCT in urban east Africa. Outcomes were modelled based on results from a randomised controlled trial of HIV-1 VCT in Tanzania and Kenya. Our main outcome measures included programme cost, number of HIV-1 infections averted, cost per HIV-1 infection averted, and cost per disability-adjusted life-year (DALY) saved. We also modelled the impact of targeting VCT by HIV-1 prevalence of the client population, and the proportion of clients who receive VCT as a couple compared with as individuals. Sensitivity analysis was done on all model parameters.\ud Findings\ud HIV-1 VCT was estimated to avert 1104 HIV-1 infections in Kenya and 895 in Tanzania during the subsequent year. The cost per HIV-1 infection averted was US$249 and$346, respectively, and the cost per DALY saved was $12·77 and$17·78. The intervention was most cost-effective for HIV-1-infected people and those who received VCT as a couple. The cost-effectiveness of VCT was robust, with a range for the average cost per DALY saved of $5·16-27·36 in Kenya, and$6·58-45·03 in Tanzania. Analysis of targeting showed that increasing the proportion of couples to 70% reduces the cost per DALY saved to $10·71 in Kenya and$13·39 in Tanzania, and that targeting a population with HIV-1 prevalence of 45% decreased the cost per DALY saved to $8·36 in Kenya and$11·74 in Tanzania.\ud Interpretation\ud HIV-1 VCT is highly cost-effective in urban east African settings, but slightly less so than interventions such as improvement of sexually transmitted disease services and universal provision of nevirapine to pregnant women in high-prevalence settings. With the targeting of VCT to populations with high HIV-1 prevalence and couples the cost-effectiveness of VCT is improved significantly

The Relationship Between Beam Power and Radio Power for Classical Double Radio Sources

Beam power is a fundamental parameter that describes, in part, the state of a supermassive black hole system. Determining the beam powers of powerful classical double radio sources requires substantial observing time, so it would be useful to determine the relationship between beam power and radio power so that radio power could be used as a proxy for beam power. A sample of 31 powerful classical double radio sources with previously determined beam and radio powers are studied; the sources have redshifts between about 0.056 and 1.8. It is found that the relationship between beam power, Lj, and radio power, P, is well described by Log(Lj) = 0.84 Log(P) + 2.15, where both L_j and P are in units of 10^(44) erg/s. This indicates that beam power is converted to radio power with an efficiency of about 0.7%. The ratio of beam power to radio power is studied as a function of redshift; there is no significant evidence for redshift evolution of this ratio over the redshift range studied. The relationship is consistent with empirical results obtained by Cavagnolo et al. (2010) for radio sources in gas rich environments, which are primarily FRI sources, and with the theoretical predictions of Willott et al. (1999).Comment: 6 pages, 2 figures, 2 tables; accepted for publication in MNRA

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic): Bay anchovy

The bay anchovy occurs along the Atlantic and Gulf of Mexico coasts, from Cape Cod, Massachusetts, to Yucatan, Mexico (Hildebrand 1963), except for the Florida Keys where it is apparently absent (Daly 1970). (PDF contains 22 pages

Cost-eff ectiveness of surgery and its policy implications for global health: a systematic review and analysis

Background The perception of surgery as expensive and complex might be a barrier to its widespread acceptance in global health eff orts. We did a systematic review and analysis of cost-eff ectiveness studies that assess surgical interventions in low-income and middle-income countries to help quantify the potential value of surgery. Methods We searched Medline for all relevant articles published between Jan 1, 1996 and Jan 31, 2013, and searched the reference lists of retrieved articles. We converted all results to 2012 US$. We extracted cost-eff ectiveness ratios (CERs) and appraised economic assessments for their methodological quality using the 10-point Drummond checklist. Findings Of the 584 identifi ed studies, 26 met full inclusion criteria. Together, these studies gave 121 independent CERs in seven categories of surgical interventions. The median CER of circumcision ($13·78 per disability-adjusted life year [DALY]) was similar to that of standard vaccinations ($12·96–25·93 per DALY) and bednets for malaria prevention ($6·48–22·04 per DALY). Median CERs of cleft lip or palate repair ($47·74 per DALY), general surgery ($82·32 per DALY), hydrocephalus surgery ($108·74 per DALY), and ophthalmic surgery ($136 per DALY) were similar to that of the BCG vaccine ($51·86–220·39 per DALY). Median CERs of caesarean sections ($315·12 per DALY) and orthopaedic surgery ($381·15 per DALY) are more favourable than those of medical treatment for ischaemic heart disease ($500·41–706·54 per DALY) and HIV treatment with multidrug antiretroviral therapy ($453·74–648·20 per DALY). Interpretation Our fi ndings suggest that many essential surgical interventions are cost-eff ective or very cost-eff ective in resource-poor countries. Quantifi cation of the economic value of surgery provides a strong argument for the expansion of global surgery’s role in the global health movement. However, economic value should not be the only argument for resource allocation—other organisational, ethical, and political arguments can also be made for its inclusion

Enumeration of nilpotent loops up to isotopy

We modify tools introduced by Daniel Daly and Petr Vojtechovsky in order to count, for any odd prime q, the number of nilpotent loops of order 2q up to isotopy, instead of isomorphy.Comment: 20 pages; important typos corrected (section 6