Nuclear tools for characterising radiological dispersion in complex terrain: evaluation of regulatory and emergency response models

Routine operations of a nuclear research reactor and its facilities offer opportunities for collection of rare environmental tracer datasets which can be used for atmospheric dispersion model evaluation studies. The HIFAR reactor near Sydney, Australia, routinely emits the radioactive noble gas Ar-41, and other radionuclides such as Xe-133 and Xe-135 are also emitted from nearby radiopharmaceutical production facilities. Despite extremely low emission levels of these gases, they are nevertheless detectable using state-of-the-art technology, and sensitive detectors have been placed at four locations in the surrounding region which features complex terrain. The high research potential of this unique dataset is illustrated in the current study, in which predictions from two atmospheric dispersion models used for emergency response are compared with Ar-41 peak observations from the detector network under a range of stability conditions, and long-term integrated data is also compared with a routine impact assessment model. © 2005, Inderscience Enterprises Ltd

Changing the Environment Based on Empowerment as Intrinsic Motivation

This is an open access article distributed under the Creative Commons Attribution License CC BY 3.0 which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.One aspect of intelligence is the ability to restructure your own environment so that the world you live in becomes more beneficial to you. In this paper we investigate how the information-theoretic measure of agent empowerment can provide a task-independent, intrinsic motivation to restructure the world. We show how changes in embodiment and in the environment change the resulting behaviour of the agent and the artefacts left in the world. For this purpose, we introduce an approximation of the established empowerment formalism based on sparse sampling, which is simpler and significantly faster to compute for deterministic dynamics. Sparse sampling also introduces a degree of randomness into the decision making process, which turns out to beneficial for some cases. We then utilize the measure to generate agent behaviour for different agent embodiments in a Minecraft-inspired three dimensional block world. The paradigmatic results demonstrate that empowerment can be used as a suitable generic intrinsic motivation to not only generate actions in given static environments, as shown in the past, but also to modify existing environmental conditions. In doing so, the emerging strategies to modify an agent’s environment turn out to be meaningful to the specific agent capabilities, i.e., de facto to its embodiment.Peer reviewedFinal Published versio

Locating farmer-based knowledge and vested interests in natural resource management: the interface of ethnopedology, land tenure and gender in soil erosion management in the Manupali watershed, Philippines

This paper examines local soil knowledge and management in the Manupali watershed in the Philippines

Differential adherence and expression of virulence traits by Candida albicans and Candida parapsilosis in mono- and dual-species cultures in artificial saliva

AIMS: To evaluate specific virulence factors of Candida albicans and Candida parapsilosis clinical oral isolates in mono- and dual-species culture in the presence of artificial saliva. METHODS AND RESULTS: Two of the strains used in this study were isolated from co-infection (C. albicans AM and C. parapsilosis AM2), and the other two were isolated from single infection (C. albicans AC and C. parapsilosis AD). The number of adhered yeast cells was measured and their enzymatic activity was determined simultaneously. In mono-species culture, C. parapsilosis strains adhered to a higher extent to the surface in comparison with the C. albicans strains. In dual-species culture, the C. parapsilosis strains adhered more in the presence of C. albicans AM. Interestingly, C. albicans AM and C. parapsilosis AD adhered to a higher extent when compared with all other co-cultures. In dual-species culture, the enzymatic activity of C. parapsilosis strains in the presence of C. albicans AC was higher than in the presence of C. albicans AM. CONCLUSIONS: The virulence factors of C. albicans and C. parapsilosis differ from strain to strain and are influenced by the presence of other species in culture. SIGNIFICANCE AND IMPACT OF THE STUDY: To understand the expression of virulence factors in Candida dual-species systems.This work was supported by Portuguese Foundation for Science and Technology (FCT) through the grant SFRH/BPD/20987/2004 attributed to Claudia Botelho

The impact on neonatal mortality of shifting childbirth services among levels of hospitals: Taiwan's experience

<p>Abstract</p> <p>Background</p> <p>There is considerable discussion surrounding whether advanced hospitals provide better childbirth care than local community hospitals. This study examines the effect of shifting childbirth services from advanced hospitals (i.e., medical centers and regional hospitals) to local community hospitals (i.e., clinics and district hospitals). The sample population was tracked over a seven-year period, which includes the four months of the 2003 severe acute respiratory syndrome (SARS) epidemic in Taiwan. During the SARS epidemic, pregnant women avoided using maternity services in advanced hospitals. Concerns have been raised about maintaining the quality of maternity care with increased demands on childbirth services in local community hospitals. In this study, we analyzed the impact of shifting maternity services among hospitals of different levels on neonatal mortality and maternal deaths.</p> <p>Methods</p> <p>A population-based study was conducted using data from Taiwan's National Health Insurance annual statistics of monthly county neonatal morality rates. Based on a pre-SARS sample from January 1998 to December 2002, we estimated a linear regression model which included "trend," a continuous variable representing the effect of yearly changes, and two binary variables, "month" and "county," controlling for seasonal and county-specific effects. With the estimated coefficients, we obtained predicted neonatal mortality rates for each county-month. We compared the differences between observed mortality rates of the SARS period and predicted rates to examine whether the shifting in maternity services during the SARS epidemic significantly affected neonatal mortality rates.</p> <p>Results</p> <p>With an analysis of a total of 1,848 observations between 1998 and 2004, an insignificantly negative mean of standardized predicted errors during the SARS period was found. The result of a sub-sample containing areas with advanced hospitals showed a significant negative mean of standardized predicted errors during the SARS period. These findings indicate that despite increased use of local community hospitals, neonatal mortality during the SARS epidemic did not increase, and even decreased in areas with advanced hospitals.</p> <p>Conclusion</p> <p>An increased use of maternity services in local community hospitals occurred during the SARS epidemic in Taiwan. However, we observed no increase in neonatal and maternity mortality associated with these increased demands on local community hospitals.</p

Freezing of spin and charge in La_(2-x)Sr_xCuO_4

Zero- and longitudinal-field muon-spin relaxation μ+SR measurements have been performed on La_(2-x)Sr_xCuO_4 alloys in both single-crystal and sintered powder forms above and below their magnetic transition temperatures, T_f. The μ+ precession frequency v depends only weakly on x and T_f, an observation which together with resistivity data implies classical freezing of magnetic moments in the regime where the carriers are localized. For x=0.05, critical dynamics are observed near T_f. The μ^+SR technique is shown to be very sensitive to ferromagnetically aligned pairs of Cu^(2+) moments; the population of such pairs increases greatly with x

Ultrasonic Monitoring of Recrystallization Textures in Aluminum

The present paper is an attempt to use ultrasonic velocity measurements to characterize the texture of an aluminum-magnesium alloy (Al 5xxx) and to compare the results with orientation imaging microscopy (OIM) results. The results are characterized in terms of three orientation distribution coefficients (ODC’s), W400, W420, and W440, each of which describes a particular forming anisotropy, and each of which has significant impact on the final products

Cross-sectional associations between sleep duration, sedentary time, physical activity, and adiposity indicators among Canadian preschool-aged children using compositional analyses

Abstract Background Sleep duration, sedentary behaviour, and physical activity are three co-dependent behaviours that fall on the movement/non-movement intensity continuum. Compositional data analyses provide an appropriate method for analyzing the association between co-dependent movement behaviour data and health indicators. The objectives of this study were to examine: (1) the combined associations of the composition of time spent in sleep, sedentary behaviour, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) with adiposity indicators; and (2) the association of the time spent in sleep, sedentary behaviour, LPA, or MVPA with adiposity indicators relative to the time spent in the other behaviours in a representative sample of Canadian preschool-aged children. Methods Participants were 552 children aged 3 to 4 years from cycles 2 and 3 of the Canadian Health Measures Survey. Sedentary time, LPA, and MVPA were measured with Actical accelerometers (Philips Respironics, Bend, OR USA), and sleep duration was parental reported. Adiposity indicators included waist circumference (WC) and body mass index (BMI) z-scores based on World Health Organization growth standards. Compositional data analyses were used to examine the cross-sectional associations. Results The composition of movement behaviours was significantly associated with BMI z-scores (p = 0.006) but not with WC (p = 0.718). Further, the time spent in sleep (BMI z-score: γ sleep  = −0.72; p = 0.138; WC: γ sleep  = −1.95; p = 0.285), sedentary behaviour (BMI z-score: γ SB  = 0.19; p = 0.624; WC: γ SB  = 0.87; p = 0.614), LPA (BMI z-score: γ LPA  = 0.62; p = 0.213, WC: γ LPA  = 0.23; p = 0.902), or MVPA (BMI z-score: γ MVPA  = −0.09; p = 0.733, WC: γ MVPA  = 0.08; p = 0.288) relative to the other behaviours was not significantly associated with the adiposity indicators. Conclusions This study is the first to use compositional analyses when examining associations of co-dependent sleep duration, sedentary time, and physical activity behaviours with adiposity indicators in preschool-aged children. The overall composition of movement behaviours appears important for healthy BMI z-scores in preschool-aged children. Future research is needed to determine the optimal movement behaviour composition that should be promoted in this age group