The identification and quantification of temperature-related mortality

The relationship between weather and mortality has been observed for centuries. Recently, studies on temperature-related mortality have become a popular topic as climate change continues. Most of the previous studies found that exposure to hot or cold temperature affects mortality. This study aims to address three research questions: 1. What is the overall effect of daily mean temperature variation on the elderly mortality in the published literature using a meta-analysis approach? 2. Does the association between temperature and mortality differ with age, sex, or socio-economic status in Brisbane? 3. How is the magnitude of the lag effects of the daily mean temperature on mortality varied by age and cause-of-death groups in Brisbane? In the meta-analysis, there was a 1-2 % increase in all-cause mortality for a 1ºC decrease during cold temperature intervals and a 2-5% increase for a 1ºC increment during hot temperature intervals among the elderly. Lags of up to 9 days in exposure to cold temperature intervals were statistically significantly associated with all-cause mortality, but no significant lag effects were observed for hot temperature intervals. In Brisbane, the harmful effect of high temperature (over 24ºC) on mortality appeared to be greater among the elderly than other age groups. The effect estimate among women was greater than among men. However, No evidence was found that socio-economic status modified the temperature-mortality relationship. The results of this research also show longer lag effects in cold days and shorter lag effects in hot days. For 3-day hot effects associated with 1°C increase above the threshold, the highest percent increases in mortality occurred among people aged 85 years or over (5.4% (95% CI: 1.4%, 9.5%)) compared with all age group (3.2% (95% CI: 0.9%, 5.6%)). The effect estimate among cardiovascular deaths was slightly higher than those among all-cause mortality. For overall 21-day cold effects associated with a 1°C decrease below the threshold, the percent estimates in mortality for people aged 85 years or over, and from cardiovascular diseases were 3.9% (95% CI: 1.9%, 6.0%) and 3.4% (95% CI: 0.9%, 6.0%), respectively compared with all age group (2.0% (95% CI: 0.7%, 3.3%)). Little research of this kind has been conducted in the Southern Hemisphere. This PhD research may contribute to the quantitative assessment of the overall impact, effect modification and lag effects of temperature variation on mortality in Australia and The findings may provide useful information for the development and implementation of public health policies to reduce and prevent temperature-related health problems.

Assessing the threshold temperatures among different age and cause-of-deaths

The relationship between temperature and mortality is non-linear and the effect estimates depend on the threshold temperatures selected. However, little is known about whether threshold temperatures differ with age or cause of deaths in the Southern Hemisphere. We conducted polynomial distributed lag non-linear models to assess the threshold temperatures for mortality from all ages (Dall), aged from 15 to 64 (D15-64), 65- 84(D65-84), ≥85 years (D85+), respiratory (RD) and cardiovascular diseases (CVD) in Brisbane, Australia, 1996–2004. We examined both hot and cold thresholds, and the lags of up to 15 days for cold effects and 3 days for hot effects. Results show that for the current day, the cold threshold was 20°C and the hot threshold was 28°C for the groups of Dall, D15-64 and D85+. The cold threshold was higher (23°C) for the group of D65-84 and lower (21°C) for the group of CVD. The hot threshold was higher (29°C) for the group of D65-84 and lower (27°C) for the group of RD. Compared to the current day, for the cold effects of up to 15-day lags, the threshold was lower for the group of D15-64, and the thresholds were higher for the groups of D65-84, D85+, RD and CVD; while for the hot effects of 3-day lags, the threshold was higher for the group of D15-64 and the thresholds were lower for the groups of D65-84 and RD. Temperature thresholds appeared to differ with age and death categories. The elderly and deaths from RD and CVD were more sensitive to temperature stress than the adult group. These findings may have implications in the assessment of temperature-related mortality and development of weather/health warning systems.

Applications of a sugar-based surveillance system to track arboviruses in wild mosquito populations

Effective arbovirus surveillance is essential to ensure the implementation of control strategies, such as mosquito suppression, vaccination, or dissemination of public warnings. Traditional strategies employed for arbovirus surveillance, such as detection of virus or virus-specific antibodies in sentinel animals, or detection of virus in hematophagous arthropods, have limitations as an early-warning system. A system was recently developed that involves collecting mosquitoes in CO2-baited traps, where the insects expectorate virus on sugar-baited nucleic acid preservation cards. The cards are then submitted for virus detection using molecular assays. We report the application of this system for detecting flaviviruses and alphaviruses in wild mosquito populations in northern Australia. This study was the first to employ nonpowered passive box traps (PBTs) that were designed to house cards baited with honey as the sugar source. Overall, 20/144 (13.9%) of PBTs from different weeks contained at least one virus-positive card. West Nile virus Kunjin subtype (WNVKUN), Ross River virus (RRV), and Barmah Forest virus (BFV) were detected, being identified in 13/20, 5/20, and 2/20 of positive PBTs, respectively. Importantly, sentinel chickens deployed to detect flavivirus activity did not seroconvert at two Northern Territory sites where four PBTs yielded WNVKUN. Sufficient WNVKUN and RRV RNA was expectorated onto some of the honey-soaked cards to provide a template for gene sequencing, enhancing the utility of the sugar-bait surveillance system for investigating the ecology, emergence, and movement of arboviruses. © 2014, Mary Ann Liebert, Inc.

Efeitos adversos da poluição atmosférica em crianças e adolescentes devido a queimadas na Amazônia: uma abordagem de modelos mistos em estudos de painel

Esta tese investiga os efeitos agudos da poluição atmosférica no pico de fluxo expiratório (PFE) de escolares com idades entre 6 e 15 anos, residentes em municípios da Amazônia Brasileira. O primeiro artigo avaliou os efeitos do material particulado fino (PM2,5) no PFE de 309 escolares do município de Alta Floresta, Mato Grosso (MT), durante a estação seca de 2006. Modelos de efeitos mistos foram estimados para toda a amostra e estratificados por turno escolar e presença de sintomas de asma. O segundo artigo expõe as estratégias utilizadas para a determinação da função de variância do erro aleatório dos modelos de efeitos mistos. O terceiro artigo analisa os dados do estudo de painel com 234 escolares, realizado na estação seca de 2008 em Tangará da Serra, MT. Avaliou-se os efeitos lineares e com defasagem distribuída (PDLM) do material particulado inalável (PM10), do PM2,5 e do Black Carbon (BC) no PFE de todos os escolares e estratificados por grupos de idade. Nos três artigos, os modelos de efeitos mistos foram ajustados por tendência temporal, temperatura, umidade e características individuais. Os modelos também consideraram o ajuste da autocorrelação residual e da função de variância do erro aleatório. Quanto às exposições, foram avaliados os efeitos das exposições de 5hs, 6hs, 12hs e 24hs, no dia corrente, com defasagens de 1 a 5 dias e das médias móveis de 2 e 3 dias. No que se refere aos resultados de Alta Floresta, os modelos para todas as crianças indicaram reduções no PFE variando de 0,26 l/min (IC95%: 0,49; 0,04) a 0,38 l/min (IC95%: 0,71; 0,04), para cada aumento de 10g/m3 no PM2,5. Não foram observados efeitos significativos da poluição no grupo das crianças asmáticas. A exposição de 24hs apresentou efeito significativo no grupo de alunos da tarde e no grupo dos não asmáticos. A exposição de 0hs a 5:30hs foi significativa tanto para os alunos da manhã quanto para a tarde. Em Tangará da Serra, os resultados mostraram reduções significativas do PFE para aumentos de 10 unidades do poluente, principalmente para as defasagens de 3, 4 e 5 dias. Para o PM10, as reduções variaram de 0,15 (IC95%: 0,29; 0,01) a 0,25 l/min (IC95%: 0,40 ; 0,10). Para o PM2,5, as reduções estiveram entre 0,46 l/min (IC95%: 0,86 to 0,06 ) e 0,54 l/min (IC95%: 0,95; 0,14). E no BC, a redução foi de aproximadamente 0,014 l/min. Em relação ao PDLM, efeitos mais importantes foram observados nos modelos baseados na exposição do dia corrente até 5 dias passados. O efeito global foi significativo apenas para o PM10, com redução do PFE de 0,31 l/min (IC95%: 0,56; 0,05). Esta abordagem também indicou efeitos defasados significativos para todos os poluentes. Por fim, o estudo apontou as crianças de 6 a 8 anos como grupo mais sensível aos efeitos da poluição. Os achados da tese sugerem que a poluição atmosférica decorrente da queima de biomassa está associada a redução do PFE de crianças e adolescentes com idades entre 6 e 15 anos, residentes na Amazônia Brasileira.

Effects of quantitative easing on the USA economy: A test for policy effectiveness

The catastrophic disruption in the USA financial system in the wake of the financial crisis prompted the Federal Reserve to launch a Quantitative Easing (QE) programme in late 2008. In line with Pesaran and Smith (2014), I use a policy effectiveness test to assess whether this massive asset purchase programme was effective in stimulating the economic activity in the USA. Specifically, I employ an Autoregressive Distributed Lag Model (ARDL), in order to obtain a counterfactual for the USA real GDP growth rate. Using data from 1983Q1 to 2009Q4, the results show that the beneficial effects of QE appear to be weak and rather short-lived. The null hypothesis of policy ineffectiveness is not rejected, which suggests that QE did not have a meaningful impact on output growth.

Markovian Processes, Two-Sided Autoregressions and Finite-Sample Inference for Stationary and Nonstationary Autoregressive Processes.

In this paper, we develop finite-sample inference procedures for stationary and nonstationary autoregressive (AR) models. The method is based on special properties of Markov processes and a split-sample technique. The results on Markovian processes (intercalary independence and truncation) only require the existence of conditional densities. They are proved for possibly nonstationary and/or non-Gaussian multivariate Markov processes. In the context of a linear regression model with AR(1) errors, we show how these results can be used to simplify the distributional properties of the model by conditioning a subset of the data on the remaining observations. This transformation leads to a new model which has the form of a two-sided autoregression to which standard classical linear regression inference techniques can be applied. We show how to derive tests and confidence sets for the mean and/or autoregressive parameters of the model. We also develop a test on the order of an autoregression. We show that a combination of subsample-based inferences can improve the performance of the procedure. An application to U.S. domestic investment data illustrates the method.

Spatial and temporal definition of Ochlerotatus camptorhynchus (Thomson) (Diptera: Culicidae) in the Gippsland Lakes system of eastern Victoria

The confirmed vector of Ross River virus, Ochlerotatus camptorhynchus (Thomson), is the dominant mosquito species inhabiting saline marshes in coastal Victoria. This paper re-examines previously published data on Oc. camptorhynchus, plus additional data collected since that time, and provides greater spatial and temporal definition of Oc. camptorhynchus numbers at seven sites across the Gippsland Lakes system of eastern Victoria. A total of 357 672 Oc. camptorhynchus was captured from 1188 trap-nights across the seven trap sites during trapping seasons from 1990 to 2001. The  dominance of Oc. camptorhynchus across the seven sites averaged 75%, with significant differences in mean abundance of Oc. camptorhynchus found between all trap sites. Significant differences in monthly abundance of Oc. camptorhynchus were observed for Wellington Shire. Increase in populations of Oc. camptorhynchus was associated with increases in rainfall at all trap sites, higher minimum temperatures at two of the seven trap sites, and wind speed at one trap site. Prioritisation of mosquito control may be applied based on spatial and temporal factors according to the findings of this study.

Is devaluation expansionary or contractionary? empirical evidence from Fiji

Devaluation has been traditionally promoted as an effective tool for increasing exports and improving the external position of the devaluing country if a nominal devaluation results in expenditure switching. In this article, our aim is to model the relationship between currency devaluations and output for Fiji. Following the approach in Bahmani et al. (2002), we extend the traditional model by incorporating other monetary and fiscal policy variables. We achieve our goal by using the recently developed bounds testing approach to cointegration and the autoregressive distributed lag model and find that devaluation is expansionary in the case of Fiji.

Estimating impacts of consumer prices on house prices

Real estate is widely considered as a reliable hedge of inflation rate and there have been many literatures examining the inflation-hedging characteristics of the real estate.  The study described in the paper focuses on testing the significances of impacts of consumer price on house price in eight Australia's capital cities.  The Autoregressive Distributed Lag model is introduced to obtain  the estimates of the coefficient.  The significances of the impacts are defined as the accept probability of t statistics of the coefficients.  Analyses and comparisons of these significances suggested that the impacts of consumer prices on house prices depend on the inherent characteristics of cities. 

Examining the relationship between trade balance and exchange rate : the case of China's trade with the USA

In this paper, we investigate the nexus between China's trade balance and the real exchange rate vis-à-vis the USA. Using the bounds testing approach to cointegration, we find evidence that China's trade balance and real exchange rate vis-à-vis the USA are cointegrated, and using the autoregressive distributed lag model we find that in both the short run and the long run a real devaluation of the Chinese RMB improves the trade balance; as a result, there is no evidence of a J-curve type adjustment.

Determinants of female fertility in Taiwan, 1966–2001 : empirical evidence from cointegration and variance decomposition analysis

This study investigates the determinants of the fertility rate in Taiwan over the period 1966–2001. Consistent with theory, the key explanatory variables in Taiwan's fertility model are real income, infant mortality rate, female education and female labor force participation rate. The test for cointegration is based on the recently developed bounds testing procedure while the long-run and short-run elasticities are based on the autoregressive distributed lag model. Among our key results, female education and female labor force participation rate are found to be the key determinants of fertility in Taiwan in the long run. The variance decom-position analysis indicates that in the long run approximately 45percent of the variation in fertility is explained by the combined impact of female labor force participation, mortality and income, implying that socioeconomic development played an important role in the fertility transition in Taiwan. This result is consistent with the traditional structural hypothesis.

Savings behaviour in Fiji : an empirical assessment using the ARDL approach to cointegration

Purpose – This paper aims to delineate the short- and long-run relationships between savings, real interest rate, income, current account deficits (CADs) and age dependency ratio in Fiji using cointegration and error correction models over the period 1968-2000.

Design/methodology/approach – The recently developed bounds testing approach to cointegration is used, which is applicable irrespective of whether the underlying variables are integrated of order one or order zero. Given the small sample size in this study, appropriate critical values were extracted from Narayan. To estimate the short- and long-run elasticities, the autoregressive distributed-lag model is used.

Findings – In the short- and long-run: a 1 per cent increase in growth rate increases savings by over 0.07 and 0.5 per cent, respectively; a 1 per cent increase in the CAD reduces savings rate by 0.01 and 0.02 per cent, respectively; and the negative coefficient on the real interest rate implies that the income effect dominates the substitution effect, while in the short-run the total effect of the real interest rate is positive, implying that the substitution effect dominates the income effect.

Originality/value – This paper makes the first attempt at estimating the savings function for the Fiji Islands. Given that Fiji's capital market is poorly developed, the empirical findings here have direct policy relevance.

Why do Australians, New Zealanders and Americans travel to Fiji? Evidence from cointegration, unit roots and parameter stability tests

The aim of this study was to estimate the demand for Fiji’s tourism from its three main source markets—Australia, New Zealand, and the US—using the bounds testing approach to cointegration. Our main finding was that visitor arrivals to Fiji and its key determinants are cointegrated over the 1970–2000 period. We then used the autoregressive distributed lag model to estimate short-run and long-run elasticities and found that income in origin countries, transport costs, and prices were significant determinants of Fiji’s tourism demand. We also found that coups negatively impact visitor arrivals from all markets. In testing for parameter stability, we established that the series were integrated of order one in the presence of a structural break. We then used the Hansen test for parameter stability and found that the parameters of our long-run model are stable over time.

An empirical analysis of Fiji’s import demand function

Purpose – This paper aims to estimate a disaggregated import demand model for Fiji using relative prices, total consumption, investment expenditure and export expenditure variables for the period 1970 to 2000.

Design/methodology/approach – The recently developed bounds testing approach to cointegration to test for a long run relationship is used, while the autoregressive distributed lag model is used to estimate short run and long run elasticities. These methodologies are shown to perform well in small sample sizes, particularly given that the bounds F-test critical values for small sample sizes generated by Narayan in 2004 and 2005 are used.

Findings – Amongst the key results it is found: a long run cointegration relationship among the variables when import demand is the dependent variable; and import demand to be inelastic and statistically significant at the 1 per cent level with respect to all the explanatory variables in both the long-run and the short-run.

Originality/value – The disaggregated import demand model estimated here provides a complete picture of the determinants of Fiji's imports. This model can be used by Fijian policy makers to draw pertinent policies and forecast import demand for Fiji.

Ecology and control of the southern saltmarsh mosquito, Ochlerotatus Camptorhynchus(Thomson), in Victoria

This study has revealed important ecological attributes of the southern saltmarsh mosquito in Victoria, resulting in an increased understanding of population peaks and their relation to Ross River virus disease and meteorological factors. Together with new information on its larval development, these results have further increased options for its control by local governments and public health authorities.