Change point detection in time series data with random forests

A large class of monitoring problems can be cast as the detection of a change in the parameters of a static or dynamic system, based on the effects of these changes on one or more observed variables. In this paper, the use of random forest models to detect change points in dynamic systems is considered. The approach is based on the embedding of multivariate time series data associated with normal process conditions, followed by the extraction of features from the resulting lagged trajectory matrix. The features are extracted by recasting the data into a binary classification problem, which can be solved with a random forest model. A proximity matrix can be calculated from the model and from this matrix features can be extracted that represent the trajectory of the system in phase space. The results of the study suggest that the random forest approach may afford distinct advantages over a previously proposed linear equivalent, particularly when complex nonlinear systems need to be monitored.     

Constraints to wildlife harvesting among aboriginal communities in Alaska and Canada

A large body of research confirms that access to wildlife resources can reduce conditions of food insecurity and health related illness among Aboriginal peoples in Canada and Alaska. Yet the procurement of wildfoods depends on the ability of Aboriginal households to overcome a range of obstacles that impede such access. Utilizing a data set collected between 2007 and 2013, this paper identifies a range of barriers that Aboriginal households in Alaska (Gwich’in), Alberta (Cree), Nunavik (Inuit), and Nunatsiavut (Inuit) encounter in accessing wildfoods. The results demonstrate that the constraints experienced by Aboriginal peoples in Canada and Alaska in accessing wildfoods are experienced differently depending on region, community, age, gender, and the political environment in which wildlife harvesting occurs. These findings underscore the diversity of factors that can influence one’s access to wildlife resources, and one’s chance of being food insecure. It is hoped that the results of this research will lead to a more informed understanding of Aboriginal food security in the Arctic and Sub-Arctic Regions of North America, and can contribute to more flexible policies that can account for the social, economic and political diversity in which Aboriginal food insecurity is experienced.     

Simulated rain events on an urban roadway to understand the dynamics of mercury mobilization in stormwater runoff

This research focuses on mercury (Hg) mobilization in stormwater runoff from an urban roadway. The objectives were to determine: how the transport of surface-derived Hg changes during an event hydrograph; the influence of antecedent dry days on the runoff Hg load; the relationship between total suspended sediments (TSS) and Hg transport, and; the fate of new Hg input in rain and its relative importance to the runoff Hg load. Simulated rain events were used to control variables to elucidate transport processes and a Hg stable isotope was used to trace the fate of Hg inputs in rain. The results showed that Hg concentrations were highest at the beginning of the hydrograph and were predominately particulate bound (HgP). On average, almost 50% of the total Hg load was transported during the first minutes of runoff, underscoring the importance of the initial runoff on load calculations. Hg accumulated on the road surface during dry periods resulting in the Hg runoff load increasing with antecedent dry days. The Hg concentrations in runoff were significantly correlated with TSS concentrations (mean r² = 0.94 ± 0.09). The results from the isotope experiments showed that the new Hg inputs quickly become associated with the surface particles and that the majority of Hg in runoff is derived from non-event surface-derived sources.     

Validation of a dynamic model for wood pellet boilers and stoves

Optimising systems with wood pellet boilers or stoves using simulations requires realistic computer models. The objective of this work was to develop and verify a mathematical model for wood pellet boilers and stoves for use in system simulations with the dynamic simulation programme TRNSYS, calculating both the energy balance and the CO-emissions (carbon monoxide emissions). Laboratory measurements have been carried out and a mathematical two-node model was developed and implemented as a TRNSYS component. Parameters were identified and the model has been compared with measurements. The model shows in general good agreement with measured data, however there are details that could be improved. This involves improved modelling of the dynamic response for boilers with large water volumes and improved modelling of the air factor and the CO-emissions, especially during start and stop conditions. Further improved methodology and accuracy for measuring and parameter identification is recommended.     

Groundwater changes in the Wairakei–Tauhara geothermal system

Overlying most of the Wairakei–Tauhara geothermal system is a sequence of shallow aquifers. Some of these are groundwaters heated by fluids escaping from the deep geothermal reservoir, others are cold; some are extensive and confined, others are perched, unconfined and of limited extent. Water levels of some of the shallow aquifers have declined at various times throughout the history of geothermal development. One of the mechanisms causing the observed changes is an increase in groundwater downflow into depressurizing steam zones. This occurs through natural fractures that once channelled the ascent of two-phase fluids. Another important mechanism is internal downflow within boreholes connecting permeable aquifers that were otherwise hydrologically separated. These cool downflows have had a significant impact on the deeper reservoir, and also affect the discharge characteristics of surface thermal features. However, in the Southern Tauhara sector, outflows of dilute chloride fluid from shallow thermal aquifers have not been affected by the deep pressure drawdown. This could be attributed to liquid or two-phase upflow continuing to recharge the chloride component in the south, or to significant quantities of residual chloride in a large geothermally heated aquifer still masking recharge depletion that has occurred during the last 50 years.     

Diagnostics and Therapeutics in Targeting HER2 Breast Cancer: A Novel Approach

Breast cancer is one of the most commonly occurring cancers in women globally and is the primary cause of cancer mortality in females. BC is highly heterogeneous with various phenotypic expressions. The overexpression of HER2 is responsible for 15–30% of all invasive BC and is strongly associated with malignant behaviours, poor prognosis and decline in overall survival. Molecular imaging offers advantages over conventional imaging modalities, as it provides more sensitive and specific detection of tumours, as these techniques measure the biological and physiological processes at the cellular level to visualise the disease. Early detection and diagnosis of BC is crucial to improving clinical outcomes and prognosis. While HER2-specific antibodies and nanobodies may improve the sensitivity and specificity of molecular imaging, the radioisotope conjugation process may interfere with and may compromise their binding functionalities. Aptamers are single-stranded oligonucleotides capable of targeting biomarkers with remarkable binding specificity and affinity. Aptamers can be functionalised with radioisotopes without compromising target specificity. The attachment of different radioisotopes can determine the aptamer’s functionality in the treatment of HER2(+) BC. Several HER2 aptamers and investigations of them have been described and evaluated in this paper. We also provide recommendations for future studies with HER2 aptamers to target HER2(+) BC.     

Effects of eight weeks of an alleged aromatase inhibiting nutritional supplement 6-OXO (androst-4-ene-3,6,17-trione) on serum hormone profiles and clinical safety markers in resistance-trained, eugonadal males

The purpose of this study was to determine the effects of 6-OXO, a purported nutritional aromatase inhibitor, in a dose dependent manner on body composition, serum hormone levels, and clinical safety markers in resistance trained males. Sixteen males were supplemented with either 300 mg or 600 mg of 6-OXO in a double-blind manner for eight weeks. Blood and urine samples were obtained at weeks 0, 1, 3, 8, and 11 (after a 3-week washout period). Blood samples were analyzed for total testosterone (TT), free testosterone (FT), dihydrotestosterone (DHT), estradiol, estriol, estrone, SHBG, leutinizing hormone (LH), follicle stimulating hormone (FSH), growth hormone (GH), cortisol, FT/estradiol (T/E). Blood and urine were also analyzed for clinical chemistry markers. Data were analyzed with two-way MANOVA. For all of the serum hormones, there were no significant differences between groups (p > 0.05). Compared to baseline, free testosterone underwent overall increases of 90% for 300 mg 6-OXO and 84% for 600 mg, respectively (p < 0.05). DHT underwent significant overall increases (p < 0.05) of 192% and 265% with 300 mg and 600 mg, respectively. T/E increased 53% and 67% for 300 mg and 600 mg 6-OXO, respectively. For estrone, 300 mg produced an overall increase of 22%, whereas 600 mg caused a 52% increase (p < 0.05). Body composition did not change with supplementation (p > 0.05) and clinical safety markers were not adversely affected with ingestion of either supplement dose (p > 0.05). While neither of the 6-OXO dosages appears to have any negative effects on clinical chemistry markers, supplementation at a daily dosage of 300 mg and 600 mg for eight weeks did not completely inhibit aromatase activity, yet significantly increased FT, DHT, and T/E.     

If-then contingencies and the differential effects of the availability of an attractive alternative on relationship maintenance for men and women.

In 7 experiments, the causal effects of the availability of an attractive alternative (AA) relationship partner on current relationship thoughts and intentions were tested using confederates, mental simulations, and virtual reality. Men behaved consistent with traditional relationship-commitment theories, showing decreased willingness to tolerate their partner's transgressions after the availability of an AA was made salient. However, consistent with a motivated cognition approach to commitment and work on relational self-construals, women increased their tolerance when presented with the relationship threat of an alternative. Word-fragment and lexical decision data suggested that AAs may activate threat for women, and their ability to dampen threat accessibility is associated with prorelationship responses. Finally, this "if relationship is threatened, then defend the relationship" contingency was induced in men with an implementation intention induction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)