Sequential Implementation of Monte Carlo Tests with Uniformly Bounded Resampling Risk

This paper introduces an open-ended sequential algorithm for computing the p-value of a test using Monte Carlo simulation. It guarantees that the resampling risk, the probability of a different decision than the one based on the theoretical p-value, is uniformly bounded by an arbitrarily small constant. Previously suggested sequential or non-sequential algorithms, using a bounded sample size, do not have this property. Although the algorithm is open-ended, the expected number of steps is finite, except when the p-value is on the threshold between rejecting and not rejecting. The algorithm is suitable as standard for implementing tests that require (re-)sampling. It can also be used in other situations: to check whether a test is conservative, iteratively to implement double bootstrap tests, and to determine the sample size required for a certain power.Comment: Major Revision 15 pages, 4 figure

Hydraulic residence time and iron removal in a wetland receiving ferruginous mine water over a 4 year period from commissioning.

Analysis of residence time distribution (RTD) has been conducted for the UK Coal Authority's mine water treatment wetland at Lambley, Northumberland, to determine the hydraulic performance of the wetland over a period of approximately 4 years since site commissioning. The wetland RTD was evaluated in accordance with moment analysis and modelled based on a tanks-in-series (TIS) model to yield the hydraulic characteristics of system performance. Greater hydraulic performance was seen during the second site monitoring after 21 months of site operation i.e. longer hydraulic residence time to reflect overall system hydraulic efficiency, compared to wetland performance during its early operation. Further monitoring of residence time during the third year of wetland operation indicated a slight reduction in hydraulic residence time, thus a lower system hydraulic efficiency. In contrast, performance during the fourth year of wetland operation exhibited an improved overall system hydraulic efficiency, suggesting the influence of reed growth over the lifetime of such systems on hydraulic performance. Interestingly, the same pattern was found for iron (which is the primary pollutant of concern in ferruginous mine waters) removal efficiency of the wetland system from the second to fourth year of wetland operation. This may therefore, reflect the maturity of reeds for maintaining efficient flow distribution across the wetland to retain a longer residence time and significant fractions of water involved to enhance the extent of treatment received for iron attenuation. Further monitoring will be conducted to establish whether such performance is maintained, or whether efficiency decreases over time due to accumulation of dead plant material within the wetland cells

Biodesalination: an emerging technology for targeted removal of Na+and Cl−from seawater by cyanobacteria

Although desalination by membrane processes is a possible solution to the problem of freshwater supply, related cost and energy demands prohibit its use on a global scale. Hence, there is an emerging necessity for alternative, energy and cost-efficient methods for water desalination. Cyanobacteria are oxygen-producing, photosynthetic bacteria that actively grow in vast blooms both in fresh and seawater bodies. Moreover, cyanobacteria can grow with minimal nutrient requirements and under natural sunlight. Taking these observations together, a consortium of five British Universities was formed to test the principle of using cyanobacteria as ion exchangers, for the specific removal of Na+ and Cl− from seawater. This project consisted of the isolation and characterisation of candidate strains, with central focus on their potential to be osmotically and ionically adaptable. The selection panel resulted in the identification of two Euryhaline strains, one of freshwater (Synechocystis sp. Strain PCC 6803) and one of marine origin (Synechococcus sp. Strain PCC 7002) (Robert Gordon University, Aberdeen). Other work packages were as follows. Genetic manipulations potentially allowed for the expression of a light-driven, Cl−-selective pump in both strains, therefore, enhancing the bioaccumulation of specific ions within the cell (University of Glasgow). Characterisation of surface properties under different salinities (University of Sheffield), ensured that cell–liquid separation efficiency would be maximised post-treatment, as well as monitoring the secretion of mucopolysaccharides in the medium during cell growth. Work at Newcastle University is focused on the social acceptance of this scenario, together with an assessment of the potential risks through the generation and application of a Hazard Analysis and Critical Control Points plan. Finally, researchers in Imperial College (London) designed the process, from biomass production to water treatment and generation of a model photobioreactor. This multimodal approach has produced promising first results, and further optimisation is expected to result in mass scaling of this process

The precautions of clinical waste: disposable medical sharps in the United Kingdom

This article deals with recent changes in UK guidance on clinical waste, in particular a shift to disposable, single-use instruments and sharps. I use interviews conducted with nurses from a GP practice and two clinical waste managers at alternative treatment and incineration sites as a springboard for reflection on the relationship between the legislation on clinical waste management and its implementation. Scrutinizing the UK guidance, European legislation and World Health Organization principles, I draw out interviewees’ concerns that the changed practices lead to an expansion of the hazardous waste category, with an increased volume going to incineration. This raises questions regarding the regulations’ environmental and health effects, and regarding the precautionary approach embedded in the regulations. Tracing the diverse reverberations of the term ‘waste’ in different points along the journeys made by sharps in particular, and locating these questions in relation to existing literature on waste, I emphasize that public health rationales for the new practices are not made clear in the guidance. I suggest that this relative silence on the subject conceals both the uncertainties regarding the necessity for these means of managing the risks of infectious waste, and the tensions between policies of precautionary public health and environmental sustainability

A comparison of drinking behavior using a harmonized methodology (Liq.In 7) in six countries

Purpose: To assess drinking occasions (volume and type) according to consumption with food in or outside meals, and location, for six countries. Methods: A total of 10, 521 participants aged 4–65 years from Argentina, Brazil, China, Indonesia, Mexico and Uruguay completed a validated 7-day fluid intake record. For each drinking event, the volume consumed, the fluid type, the location of intake, and whether the drink was accompanied by food (meal or snack) or not, was recorded. Results: Similar drinking behaviors were found in Mexico and Argentina; fluid intake during meals was 48 and 45% of total fluid intake (TFI), respectively. In Brazil (55%), Indonesia (58%) and China (66%) most fluid was consumed without food. In Uruguay, 34% of TFI was with a main meal, 31% with food between meals and 35% without food. Indonesia had the highest median (25–75th percentile) TFI; 2520 (1750–3347) mL/day, and China the lowest 1138 (818–3347) mL/day. Water was consumed with meals for 37% of Chinese and 87% of Indonesian participants, while the four Latin-American American countries showed a preference for sweet drinks; 54% in Mexico, 67% in Brazil, 55% in Argentina and 59% in Uruguay. Diversity in fluid type was noted when drinking with food between meals. Apart from China, most drinking occasions (> 75%) occurred at home. Conclusions: Three distinct drinking behaviors were identified, namely, drinking with meals, drinking as a stand-alone activity, and a type of ‘grazing’ (i.e., frequent drinks throughout the day) behavior. Most drinking occasions occurred at home

Fluid intake of children, adolescents and adults in Indonesia: results of the 2016 Liq.In7 national cross-sectional survey

Purpose: To report daily total fluid intake (TFI) and fluid types in Indonesia according to age, sex, socio-economic status (SES) and geographic region, and compare TFI with the Indonesian adequate fluid intake (AI) recommendations. Methods: Data were collected in 32 cities over nine regions from children (4–9 years, n = 388), adolescents, (10–17 years, n = 478) and adults (18–65 years, n = 2778) using a fluid intake 7-day record (Liq.In7); socio-economic status was also recorded. The 7-day mean TFIs were compared with the AI of water set by the Ministry of Health of the Republic of Indonesia. Results: Total median fluid intakes for all age groups exceeded 2000 mL/day. At population level, TFI was associated with household income (P < 0.001), education (P < 0.001) and Indonesian geographical regions (P < 0.001). More than 67% of participants met the AI of water from fluids. A higher percentage of children and adolescents met the AI (78 and 80%, respectively), compared with adults (72%). Drinking water was the main contributor to TFI in all age groups (76–81%). Sugar-sweetened beverages (SSB) were consumed by 62% children, 72% adolescents and 61% of adults. An SSB intake = 1 serving per day was observed for 24% children, 41% adolescents and 33% adults. Conclusions: A high percentage of the population drank enough to meet the AI of water from fluids. Water was the most frequently consumed drink; however, many participants consumed at least one serving of SSB per day. This study provides data to help direct targeted intervention programs

Fluid intake of Latin American children and adolescents: results of four 2016 LIQ.IN 7 National Cross-Sectional Surveys

Purpose: The primary aim of this survey was to report total fluid intake (TFI) and different fluid types for children (4–9 years) and adolescents (10–17 years) in Mexico, Brazil, Argentina and Uruguay. The second aim was to compare TFI with the adequate intake (AI) of water from fluids as recommended by the USA Institute of Medicine. Methods: Data were collected using a validated liquid intake 7-day record (Liq.In7). Participants’ characteristics, including age, sex and anthropometric measurements were recorded. Results: A total of 733 children and 933 adolescents were recruited. Over 75% of children in Uruguay met the IOM’s recommended intake. Fewer children in Argentina (64–72%) and Brazil (41–50%) obtained AI and the lowest values were recorded in Mexico (33–44%), where 16% of boys and 14% girls drank 50% or less of the AI. More adolescents in Argentina (42%) met the AIs than other countries; the lowest was in Mexico (28%). Children and adolescents in Mexico and Argentina drank more sugar sweetened beverages than water. Conclusions: Large numbers of children and adolescents did not meet AI recommendations for TFI, raising concerns about their hydration status and potential effects on mental and physical well-being. Given the negative effects on children’s health, the levels of SSB consumption are worrying

Fluid intake of Latin American adults: results of four 2016 Liq.In7 national cross-sectional surveys

Purpose: To report total fluid intake (TFI) and the intake of different fluid types in adults (= 18 years old) from Mexico, Argentina, Brazil and Uruguay. To compare intakes between countries and with recommended adequate intake (AI) of water from fluids. Methods: Cross-sectional data were collected using a validated liquid intake 7-day record (Liq.In7) in populations from Argentina (n = 1089), Brazil (n = 477), Mexico (n = 1677) and Uruguay (n = 554). Population characteristics, including age, gender, body mass index and socioeconomic level were recorded. Mean TFI was compared with the AI of water from fluids set by the USA Institute of Medicine. Results: The lowest TFI was recorded in Mexican women (1748 mL/day) and the highest in Argentinean men (2318 mL/day). Median daily TFI was significantly different between countries; Uruguay and Argentina had higher values than Mexico and Brazil. In the former, plain water contributed to only 25% of TFI, the remainder being predominantly from hot beverages. Approximately, a third of adults did not drink enough fluid to meet the recommended AI. High SSB consumption was reported, which was significantly different between countries (p < 0.05), the highest being in Mexico (median 25–75th percentiles): 531 (300–895 mL/day. Conclusions: This survey highlights the need to increase water consumption and reduce SSB intake in this region to avoid potential associated health risks. These findings may be useful information in monitoring public health policy strategies

Fluid intake patterns of children and adolescents: results of six Liq.In7 national cross-sectional surveys

Purpose: This study aimed to identify and characterize patterns of fluid intake in children and adolescents from six countries: Argentina, Brazil, China, Indonesia, Mexico and Uruguay. Methods: Data on fluid intake volume and type amongst children (4–9 years; N = 1400) and adolescents (10–17 years; N = 1781) were collected using the validated 7-day fluid-specific record (Liq.In7 record). To identify relatively distinct clusters of subjects based on eight fluid types (water, milk and its derivatives, hot beverages, sugar-sweetened beverages (SSB), 100% fruit juices, artificial/non-nutritive sweetened beverages, alcoholic beverages, other beverages), a cluster analysis (partitioning around k-medoids algorithm) was used. Clusters were then characterized according to their socio-demographics and lifestyle indicators. Results: The six interpretable clusters identified were: low drinkers–SSB (n 523), low drinkers–water and milk (n 615), medium mixed drinkers (n 914), high drinkers–SSB (n 513), high drinkers–water (n 352) and very high drinkers–water (n 264). Country of residence was the dominant characteristic, followed by socioeconomic level, in all six patterns. Conclusions: This analysis showed that consumption of water and SSB were the primary drivers of the clusters. In addition to country, socio-demographic and lifestyle factors played a role in determining the characteristics of each cluster. This information highlights the need to target interventions in particular populations aimed at changing fluid intake behavior and improving health in children and adolescents

Fluid intake in urban China: results of the 2016 Liq.In 7 national cross-sectional surveys

Purpose: To describe total fluid intake (TFI) and types of fluid consumed in urban China by age, gender, regions and city socioeconomic status relative to the adequate intakes (AI) set by the Chinese Nutrition Society. Methods: In 2016, participants aged 4–9, 10–17 and 18–55 years were recruited via a door-to-door approach in 27 cities in China. In total, 2233 participants were included. The volumes and sources of TFI were collected using the Liq.In7 record, assisted by a photographic booklet of standard fluid containers. Results: The mean daily TFI among children, adolescents and adults were 966, 1177 and 1387 mL, respectively. In each age group, TFI was significantly higher in male vs female (981 vs 949, 1240 vs 1113, 1442 vs 1332; mL). Approximately 45, 36 and 28% of children, adolescents and adults reached the AI. Although plain water was the highest contributor to TFI, the contribution of sugar sweetened beverages (SSB) was ranked in the top three together with water and milk and derivatives. Approximately 27, 48 and 47% of children, adolescents and adults consumed more than one serving of SSB per day, respectively. Conclusions: A relatively large proportion of participants did not drink enough to meet the AI in urban China. Many children, adolescents and adults consumed more than one serving of SSB per day. A majority of children, adolescents and adults in the study population do not meet both quantitative and qualitative fluid intake requirements, and signal socioeconomic disparities