Post-traumatic stress disorder: Findings from the Australian National Survey of Mental Health and Well-being

Background. We report on the epidemiology of post-traumatic stress disorder (PTSD) in the Australian community, including information on lifetime exposure to trauma, 12-month prevalence of PTSD, sociodemographic correlates and co-morbidity. Methods. Data were obtained from a stratified sample of 10641 participants as part of the Australian National Survey of Mental Health and Well-being. A modified version of the Composite International Diagnostic Interview was used to determine the presence of PTSD, as well as other DSM-IV anxiety, affective and substance use disorders. Results. The estimated 12-month prevalence of PTSD was 1.33%, which is considerably lower than that found in comparable North American studies. Although females were at greater risk than males within the subsample of those who had experienced trauma, the large gender differences noted in some recent epidemiological research were not replicated. Prevalence was elevated among the never married and previously married respondents, and was lower among those aged over 55. For both men and women, rape and sexual molestation were the traumatic events most likely to be associated with PTSD. A high level of Axis I co-morbidity was found among those persons with PTSD Conclusions. PTSD is a highly prevalent disorder in the Australian community and is routinely associated with high rates of anxiety, depression and substance disorders. Future research is needed to investigate rates among other populations outside the North American continent.

The relationship between cannabis use and other substance use in the general population

This study examined if (1) there is an association in the general population between cannabis use, DSM-IV abuse and dependence, and other substance use and DSM-IV substance abuse/dependence; (2) if so, is it explained by demographic characteristics or levels of neuroticism? It used data from the Australian National Survey of Mental Health and Well-Being (NSMHWB), a stratified, multistage probability sample of 10641 adults, representative of the general population. DSM-IV diagnoses of substance abuse and dependence were derived using the Composite International Diagnostic Interview (CIDI). There was a strong bivariate association between involvement with cannabis use in the past 12 months and other substance use, abuse and dependence. In particular, cannabis abuse and dependence were highly associated with increased risks of other substance dependence. These associations remained after including other variables in multiple regression. Cannabis use without disorder was strongly related to other drug use, an association that was not explained by other variables considered here. The high likelihood of other substance use and substance use disorders needs to be considered among persons seeking treatment for cannabis use problems. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

Patterns of co-morbidity between alcohol use and other substance use in the Australian population

The present study describes patterns of co-morbidity between alcohol use and other substance use problems in the Australian population using data from the 1997 National Survey of Mental Health and Well-Being. Multiple regression analyses examined whether the observed associations between alcohol and other drug use disorders were explained by other variables, including demographic characteristics and neuroticism. We also assessed whether the presence of co-morbid substance use disorders affected treatment seeking for a mental health problem. Alcohol use was related strongly to the use of other substances. Those who did not report alcohol use within the past 12 months were less likely to report using tobacco, cannabis, sedatives, stimulants or opiates. Higher rates again were observed among those with alcohol use disorders: half (51%) of those who were alcohol-dependent were regular tobacco smokers, one-third had used cannabis (32%); 15% reported other drug use; 15% met criteria for a cannabis use disorder and 7% met criteria for another drug use disorder. These associations were not accounted for by the demographic and other variables considered here. Co-morbid substance use disorders (sedatives, stimulants or opioids) predicted a high likelihood of seeking treatment for a mental health problem among alcohol-dependent people.

Impact of undergraduate and postgraduate rural training, and medical school entry criteria on rural practice among Australian general practitioners: national study of 2414 doctors

Objective To determine the association between rural undergraduate training, rural postgraduate training and medical school entry criteria favouring rural students, on likelihood of working in rural Australian general practice. Methods National case - control study of 2414 rural and urban general practitioners (GPs) sampled from the Health Insurance Commission database. Participants completed a questionnaire providing information on demographics, current practice location and rural undergraduate and postgraduate experience. Results Rural GPs were more likely to report having had any rural undergraduate training [ odds ratio ( OR) 1.61, 95% confidence interval (CI) 1.32 - 1.95] than were urban GPs. Rural GPs were much more likely to report having had rural postgraduate training ( OR 3.14, 95% CI 2.57 - 3.83). As the duration of rural postgraduate training increased so did the likelihood of working as a rural GP: those reporting that more than half their postgraduate training was rural were most likely to be rural GPs ( OR 10.52, 95% CI 5.39 - 20.51). South Australians whose final high school year was rural were more likely to be rural GPs ( OR 3.18, 95% CI 0.99 - 10.22). Conclusions Undergraduate rural training, postgraduate training and medical school entry criteria favouring rural students, all are associated with an increased likelihood of being a rural GP. Longer rural postgraduate training is more strongly associated with rural practice. These findings argue for continuation of rural undergraduate training opportunities and rural entry schemes, and an expansion in postgraduate training opportunities for GPs.

A study of high-speed milling characteristics of nitinol

High-speed milling (HSM) has many advantages over conventional machining. Among these advantages, the lower cutting force associated with the machining process is of particular significance for Nitinol alloys because their machined surfaces show less strain hardening. In this article, a systematic study has been carried out to investigate the machining characteristics of a Ni50.6Ti49.4 alloy in HSM. The effects of cutting speed, feed rate, and depth of cut on machined surface characteristics and tool wear are studied. It is found that an increase in cutting speed has resulted in a better surface finish and less work hardening. This is attributed to the reduction of chip cross-sectional area or chip thickness, which thus leads to a lower cutting force or load.

Impact of the Subprime Crisis in the Provision of Credit Risk of Major National Banks

Financial institutions are directly exposed to the credit risk, that is, the risk of the borrower not fulfill with their obligations, paying their debts in its stated periods established previously. The bank predict this type of risk, including them in their balance-sheets. In 2006/2007 there was the impact of a new financial crisis that spread around the world, known as the crisis of subprime. The objective of this study is to analyze if the provisions for credit risk or liquidation increased the sprouting of the crisis of subprime in ten major national banks, chosen accordant to their total assets. To answer this question, the balance-sheets of each one of these banks in the period of 2005 to 2007 were analyzed. This research is characterized, as for its objectives, as descriptive and as for the procedures as documentary research. It is also characterized as having a qualitative approach. The results show that the crisis of subprime has caused little impact in the credit risk provision of the analyzed institutions. It was noticed a slight increase in the provision indicators at the peak of the crisis in 2006. These percentages were reduced in, 2007, probably reflecting the economic stability of Brazil and the stagnation of the crisis Of subprime in that year, at least in relation to in our country.

Country risk, national cultural differences between partners and survival of international joint ventures in Brazil

This article aims to identify the main and interaction effects of two country-level variables, namely national distance and country risk, on the survival of international joint ventures in emerging markets. Research hypotheses predicting the negative impact of national distance and country risk on survival of international joint ventures are formulated in this article. These research hypotheses are examined in a sample of 234 international joint ventures formed in Brazil between 1973 and 2004. These international joint ventures were subjected to an event history analysis over a period of time ranging from 1973 to 2006. The empirical results show that large national cultural differences between local and foreign partners increase the instability of international joint ventures, whereas the survival of these alliances does not seem to be affected either by the economic and political uncertainty of Brazil. Furthermore, the national distance between local and foreign partners has effects on survival that are variable according to the life cycle of international joint ventures. (C) 2007 Elsevier Ltd. All rights reserved.

Thermal Characteristics of Polybia scutellaris Nests (Hymenoptera: Vespidae) Using Computational Fluid Dynamics: A Possible Adaptation to Tropical Climates

Polybia scutellaris constructs huge nests characterized by numerous spinal projections on the surface. We investigated the thermal characteristics of P scutellaris nests in order to determine whether their nest temperature is homeothermically maintained and whether the spines play a role in the thermoregulation of the nests. In order to examine these hypotheses, we measured the nest temperature in a active nest and in an abandoned nest. The temperature in the active nest was almost stable at 27 degrees C, whereas that of the abandoned nest varied with changes in the ambient temperature, suggesting that nest temperature was maintained by the thermogenesis of colony individuals. In order to predict the thermal properties of the spines, a numerical simulation was employed. To construct a 3D-model of a P scutellaris nest, the nest architecture was simplified into an outer envelope and the surface spines, for both of which the initial temperature was set at 27 degrees C. The physical properties of the simulated nest were regarded to be those of wood since the nest of this species is constructed from plant materials. When the model was exposed to cool air (12 degrees C), the temperature was lower in the models with more spines. On the other hand, when the nest was heated (42 degrees C), the temperature increase was smaller in models with more spines. It is suggested that the spines act as a heat radiator, not as an insulator, against the changes in ambient temperature.

Thermal Characteristics of the Mud Nests of the Social Wasp Polybia spinifex (Hymenoptera; Vespidae)

The thermal characteristics of mud nests of Polybia spinifex were investigated by measuring internal and surface temperatures of the nests. The nests had a layer of mud envelope and consisted of mud with fine sand particles. The envelope had a vertically long slit-like entrance hole. The mud nests had high thermal conductivities (0.51-0.67 W/(m degrees C)) comparable to brick, rather than insulation materials of wasps` nests such as paper and wood. It was revealed that the long entrance radiated more heat from the thereto-image. The rate of thermal radiation (emissivity) of the nest surface was 0.80, and the value was similar to that of sand. The internal temperatures of the nests were high from top (T(n1), temperature difference between ambient temperature (T(a)) was 10 degrees C) to bottom (T(n3), difference, 5 degrees C) at noon. On the other hand, the temperature distributions were reversed during the night. Temperature T(n1) was lower by 1 degrees C than T(a), possibly from nightly dew on the top surface, whereas, at the middle point (T(n2),) and T(n3), temperatures were higher by 1 degrees C compared to T(a). Temperature fluctuations (ranges between maximum and minimum temperature) at T(n2) and T(n3) were similar to that of T(a), whereas the values at T(n1) and T(s) were higher than that of T(a).

Aquisition and extinction of two characteristics consistent with fear relevance

Fear relevance, the potential of a stimulus to become quickly associated with fear, is a characteristic assumed to have an evolutionary basis and to result in preferential processing. Previous research has shown that fear relevant stimuli share a number of characteristics, negative valence and preferential identification in a visual search task, for instance. The present research examined whether these two characteristics can be acquired by non-fear relevant stimuli (geometric shapes) as a result of Pavlovian fear conditioning. Two experiments employed an aversive learning paradigm with geometric shape CSs and a shock US, with stimulus ratings, affective priming and visual search performance assessed before and after acquisition and after extinction. Differential electrodermal responses, larger during CS1 than CS, were present during acquisition but not during extinction. Affective priming results suggest that the CS1 acquired negative valence during acquisition, which was lost during extinction. However, negative valence as indexed by more negative ratings for CS1 than for CS shapes seemed to survive extinction. Preferential attentional processing as indexed by faster detection of CS1 among CS shapes than vice versa on the visual search task also remained. The current research confirmed that characteristics of fear relevant stimuli can be acquired in an aversive learning episode and that they may be extinguished. This supports the proposal that fear relevance may be malleable through learning.

Maturation temperature and rainfall influence seed dormancy characteristics of annual ryegrass (Lolium rigidum)

The role of temperature and rainfall during seed development in modulating subsequent seed dormancy status was studied for Lolium rigidum Gaud. (annual ryegrass). Climatic parameters relating to geographic origin were compared with annual ryegrass seed dormancy characteristics for seeds collected from 12 sites across the southern Western Australian cropping region. Seed germination was tested soon after collection and periodically during subsequent after-ripening. Temperature in the year of seed development and long-term rainfall patterns showed correlations with aspects of seed dormancy, particularly the proportion of seeds remaining dormant following 5 months of after-ripening. Consequently, for one population the temperature (warm/cool) and water supply (adequate/reduced) during seed development were manipulated to investigate the role of maternal environment in the quantity and dormancy characteristics of seeds produced. Seeds from plants grown at warm temperatures were fewer in number, weighed less, and were less dormant than those from plants grown at cool temperature. Seeds that developed under both cool temperature and reduced moisture conditions lost dormancy faster than seeds from well-watered plants. Seed maturation environment, particularly temperature, can have a significant effect on annual ryegrass seed numbers and seed dormancy characteristics.