Recent years have seen a global rise in the failure of tailings dams. Studies investigating the causes of slope failure often recognise high intensity rainfall events to significantly contribute to liquefaction, erosion and overtopping. This study aims to investigate the influence of alternative physical and geohydrological processes that, under tension saturation conditions, contribute to slope instability in tailings dams. It has been suggested that the generation of transient pressure wave mechanisms by high intensity rainfall events, surface ponding and wetting front advancement result in the formation of an induced pressure head that triggers the mobilization of pre-event water. In order to quantify these physical processes, this study included the analysis of rapid transmission conditions in a silica fines mix, with similar physical and hydraulic characteristics as platinum tailings. A tall leak-proof soil column, containing the soil sample compacted to in-situ dry bulk density, was fitted with seven observation ports. Each port consisted of a pore air pressure probe, a mini tensiometer and a time domain reflectometry probe. After set-up and initial stabilisation, three separate artificial high intensity rainfall events were applied to the surface. Monitoring of hydraulic state variables was recorded at thirty second intervals by automatic logging, thereby enabling the analysis of measured outcomes. Observations showed instant spikes in pore air pressure ahead of the wetting front, as well as a number of delayed responses. The interpretation of lab results led to the conclusion that pressure diffusion mechanisms throughout the porous medium, could result in the rapid release and mobilisation of previously stagnant antecedent moisture, thereby enabling phreatic levels to rising rapidly and in excess to the amount of surface infiltration. Also, since an increase in pore water pressure is likely to cause a reduction in shear strength, it is suggested that these physical and geohydrological processes could have an adverse impact on the stability of tailings dams.
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Accurate modeling of end-users’ decision-making behavior is crucial for validating demand response (DR) policies. However, existing models usually represent the decision-making behavior as an optimization problem, neglecting the impact of human psychology on decisions. In this paper, we propose a Belief-Desire-Intention (BDI) agent model to model end-users’ decision-making under DR. This model has the ability to perceive environmental information, generate different power scheduling plans, and make decisions that align with its own interests. The key modeling capabilities of the proposed model have been validated in a household end-user with flexible loads
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Limited evidence is available about (non)-representativeness of participants in health-promoting interventions. The Dutch Healthy Primary School of the Future (HPSF)-study is a school-based study aiming to improve health through altering physical activity and dietary behaviour, that started in 2015 (registered in ClinicalTrials.gov on14-06-2016, NCT02800616). The study has a response rate of 60%. A comprehensive non-responder analysis was carried out, and responders were compared with schoolchildren from the region and the Netherlands using a cross-sectional design. External sources were consulted to collect non-responder, regional, and national data regarding relevant characteristics including sex, demographics, health, and lifestyle. The Chi-square test, Mann-Whitney U test, or Student's t-test were used to analyse differences.
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Even though mango productivity in Ethiopia is low due to moisture stress, there is no report on how such constraint could alleviate using Cocoon water-saving technology. Cocoon is small water reservoir technology which uses for plant growth in dry season. The objectives of this study were to introduce and evaluate effectiveness of water-saving techniques on mango seedlings survival and growth in Mihitsab-Azmati watershed, northern Ethiopia. In this experiment, five treatments of water-saving techniques with mango seedlings were evaluated. These were: Cocoon sprayed by tricel (T1), Cocoon painted by used engine oil (T2), Cocoon without tricel and oil (T3), manually irrigated seedlings (T4) and mango seedlings planted during rainy season (T5). The survival and growth performance of mango seedlings were recorded at six months and one-year after transplanting. Data on plant survival, height, number of leaves per plant, shoot length, stem diameter and crown width were subjected to analysis of variance and t-test. There were significant differences in the treatment effects on mango seedlings transplanted survival, plant height, number of leaves per plant, shoot length, stem diameter and crown width measured at six months and one-year after transplanting. The lowest survival rate (20 %) was found during both data collection time in T5. Six months after transplanting, the highest growth parameters were measured from T1 whereas the lowest was from T5. However, one-year after transplanting, the highest growth parameters were measured from T3. Plant heights increments between the two measurement periods for T3, T2, T1, T4 and T5 were 45.1, 38.5, 24.8, 9.8 and 7.0 cm, respectively; indicating that T3 performed better than the other treatments. The t-test on mean differences between the same growth parameter measured at 12 and six months after transplanting also showed significant differences. The Cocoon water-saving technology was superior in improving mango seedlings survival and growth in the study area. This study generalized that Cocoon seems promising, sustainable and highly scalable with mango seedlings at large-scale in the study area conditions. However, this technology should not be assumed to perform uniformly well in all environmental conditions and with all tree species before demonstrated on a pilot study.
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Computer security incident response teams (CSIRTs) respond to a computer security incident when the need arises. Failure of these teams can have far-reaching effects for the economy and national security. CSIRTs often have to work on an ad hoc basis, in close cooperation with other teams, and in time constrained environments. It could be argued that under these working conditions CSIRTs would be likely to encounter problems. A needs assessment was done to see to which extent this argument holds true. We constructed an incident response needs model to assist in identifying areas that require improvement. We envisioned a model consisting of four assessment categories: Organization, Team, Individual and Instrumental. Central to this is the idea that both problems and needs can have an organizational, team, individual, or technical origin or a combination of these levels. To gather data we conducted a literature review. This resulted in a comprehensive list of challenges and needs that could hinder or improve, respectively, the performance of CSIRTs. Then, semi-structured in depth interviews were held with team coordinators and team members of five public and private sector Dutch CSIRTs to ground these findings in practice and to identify gaps between current and desired incident handling practices. This paper presents the findings of our needs assessment and ends with a discussion of potential solutions to problems with performance in incident response. https://doi.org/10.3389/fpsyg.2017.02179 LinkedIn: https://www.linkedin.com/in/rickvanderkleij1/
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Legislation in the Netherlands requires routine analysis of drinking water samples for cultivable Legionella species from high-priority installations. A field study was conducted to investigate the presence of Legionella species in thermostatic shower mixer taps. Water samples and the interior of ten thermostatic shower mixer taps were investigated for cultivable Legionella species. In seven cases, Legionella species was found in at least one of the samples. In four cases, Legionella species was detected in the biofilm on the thermostatic shower mixer taps interior, with the highest values on rubber parts, and in five cases in the cold supply water. These results show that thermostatic shower mixer taps can play a role in exceeding the threshold limit for cultivable Legionella species, but the cold supply water can also be responsible. Practical implications: This study showed that contamination of thermostatic shower mixer taps (TSMTs) with Legionella spp. was frequently observed in combination with contamination of the water system. Consequently, a combined focus is necessary to prevent the proliferation of cultivable Legionella spp. in TSMTs. In addition, the results also demonstrated that biofilms on rubbers inside the TSMT had high numbers of Legionella spp., probably because rubber contains relatively high concentrations of biodegradable substrates. Therefore, improvement of the rubber materials is necessary to reduce the proliferation of cultivable Legionella spp. in TSMTs.
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Aim and method: To examine in obese people the potential effectiveness of a six-week, two times weekly aquajogging program on body composition, fitness, health-related quality of life and exercise beliefs. Fifteen otherwise healthy obese persons participated in a pilot study. Results: Total fat mass and waist circumference decreased 1.4 kg (p = .03) and 3.1 cm (p = .005) respectively. The distance in the Six-Minute Walk Test increased 41 meters (p = .001). Three scales of the Impact of Weight on Quality of Life-Lite questionnaire improved: physical function (p = .008), self-esteem (p = .004), and public distress (p = .04). Increased perceived exercise benefits (p = .02) and decreased embarrassment (p = .03) were observed. Conclusions: Aquajogging was associated with reduced body fat and waist circumference, and improved aerobic fitness and quality of life. These findings suggest the usefulness of conducting a randomized controlled trial with long-term outcome assessments.
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Schepen in moeilijkheden op zee leveren vaak besluitvormingsproblemen op tussen de scheepseigenaar/kapitein en de kuststaat. Kuststaten en met name de lokale overheden willen een probleem schip graag zo ver mogelijk weg sturen van hun gebied terwijl de eigenaar/kapitein zijn schip graag zo snel mogelijk naar de kust, een beschutte locatie of haven wil brengen. Het onderzoek geeft onderbouwing voor de besluitvorming rond schepen in moeilijkheden, zowel voor de zeescheepvaart als de betrokken besluitvormers van oeverstaten. Het product van het project is: een, op uitgewerkte scenario’s per scheepstype en lading gebaseerde besluitvormingsprocedure voor zeeschepen in moeilijkheden
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Manure application can spread antimicrobial resistance (AMR) from manure to soil and surface water. This study evaluated the role of the soil texture on the dynamics of antimicrobial resistance genes (ARGs) in soils and surrounding surface waters. Six dairy farms with distinct soil textures (clay, sand, and peat) were sampled at different time points after the application of manure, and three representative ARGs sul1, erm(B), and tet(W) were quantified with qPCR. Manuring initially increased levels of erm(B) by 1.5 ± 0.5 log copies/kg of soil and tet(W) by 0.8 ± 0.4 log copies/kg across soil textures, after which levels gradually declined. In surface waters from clay environments, regardless of the ARG, the gene levels initially increased by 2.6 ± 1.6 log copies/L, after which levels gradually declined. The gene decay in soils was strongly dependent on the type of ARG (erm(B) < tet(W) < sul1; half-lives of 7, 11, and 75 days, respectively), while in water, the decay was primarily dependent on the soil texture adjacent to the sampled surface water (clay < peat < sand; half-lives of 2, 6, and 10 days, respectively). Finally, recovery of ARG levels was predicted after 29–42 days. The results thus showed that there was not a complete restoration of ARGs in soils between rounds of manure application. In conclusion, this study demonstrates that rather than showing similar dynamics of decay, factors such as the type of ARG and soil texture drive the ARG persistence in the environment.
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Since the early work on defining and analyzing resilience in domains such as engineering, ecology and psychology, the concept has gained significant traction in many fields of research and practice. It has also become a very powerful justification for various policy goals in the water sector, evident in terms like flood resilience, river resilience, and water resilience. At the same time, a substantial body of literature has developed that questions the resilience concept's systems ontology, natural science roots and alleged conservatism, and criticizes resilience thinking for not addressing power issues. In this study, we review these critiques with the aim to develop a framework for power-sensitive resilience analysis. We build on the three faces of power to conceptualize the power to define resilience. We structure our discussion of the relevant literature into five questions that need to be reflected upon when applying the resilience concept to social–hydrological systems. These questions address: (a) resilience of what, (b) resilience at what scale, (c) resilience to what, (d) resilience for what purpose, and (e) resilience for whom; and the implications of the political choices involved in defining these parameters for resilience building or analysis. Explicitly considering these questions enables making political choices explicit in order to support negotiation or contestation on how resilience is defined and used.
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