The strength and permeability of fault zones must be quantified in order to accurately predict crustal strength and subsurface fluid migration. To this end, we performed experiments on mixtures of ...fine‐grained quartz and kaolinite incremented at 10 wt% intervals between the two end‐member components (analogues for natural fault gouge) in order to establish their strength and fluid flow properties during hydrostatic and shear loading. Hydrostatically compacted samples exhibited permeability reduction on increasing effective pressures from 5 MPa to 50 MPa, with the rate of reduction displaying strong dependency on the synthetic fault gouge composition. The permeability decreases continuously with increasing kaolinite content. Porosity exhibits a distinct minimum that evolves with increasing effective pressure according to the relative compaction of the quartz and kaolinite end‐members. Porosity evolution with increasing clay content is predicted satisfactorily by a simple ideal packing model. At the highest effective pressure (50 MPa), permeability reduced log‐linearly over 4 orders of magnitude with increasing clay content. Mechanically, sheared gouge samples showed a continuous reduction in frictional strength with increasing clay fraction. Permeability decreased further on shear loading after initial hydrostatic compaction to 50 MPa. This was most evident for the pure quartz end‐member, with two orders of magnitude additional reduction, whereas the clay‐rich samples were reduced only tenfold, mostly before a shear strain of 5. Variation of permeability with both clay content and shear deformation may be adequately described by previously published empirical predictors for fault zone permeability. Clay content has the largest effect on permeability, and shear deformation affects permeability of quartz‐rich gouges more than clay‐rich gouges.
To examine the impact of traffic on levels of walking and bicycling.
Review of the literature of medical, public health, city planning, public administration and traffic engineering.
The real and ...perceived danger and discomfort imposed by traffic discourage walking and bicycling. Accurately or not, pedestrians and bicyclists judge injury risk and respond accordingly. Although it can be difficult to measure these effects, observed behaviour provides good evidence for these effects, with the strongest association being an inverse correlation between volumes and speeds of traffic and levels of walking and cycling.
Interventions to reduce traffic speed and volume are likely to promote walking and bicycling and thus result in public health gains.
Purpose
Dietary behaviours may be influenced by perceptions of barriers to healthy eating. Using data from a large cross-European study (
N
= 5900), we explored associations between various ...perceived barriers to healthy eating and dietary behaviours among adults from urban regions in five European countries and examined whether associations differed across regions and socio-demographic backgrounds.
Methods
Frequency of consumption of fruit, vegetables, fish, fast food, sugar-sweetened beverages, sweets, breakfast and home-cooked meals were split by the median into higher and lower consumption. We tested associations between barriers (irregular working hours; giving up preferred foods; busy lifestyle; lack of willpower; price of healthy food; taste preferences of family and friends; lack of healthy options and unappealing foods) and dietary variables using multilevel logistic regression models. We explored whether associations differed by age, sex, education, urban region, weight status, household composition or employment.
Results
Respondents who perceived any barrier were less likely to report higher consumption of healthier foods and more likely to report higher consumption of fast food. ‘Lack of willpower’, ‘time constraints’ and ‘taste preferences’ were most consistently associated with consumption. For example, those perceiving lack of willpower ate less fruit odds ratio (OR) 0.57; 95% confidence interval (CI) 0.50–0.64, and those with a busy lifestyle ate less vegetables (OR 0.54; 95% CI 0.47–0.62). Many associations differed in size, but not in direction, by region, sex, age and household composition.
Conclusion
Perceived ‘lack of willpower’, ‘time constraints’ and ‘taste preferences’ were barriers most strongly related to dietary behaviours, but the association between various barriers and lower intake of fruit and vegetables was somewhat more pronounced among younger participants and women.
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DOBA, EMUNI, FIS, FSPLJ, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Summary
Too much sitting, and both short and long sleep duration are associated with obesity, but little is known on the nature of the relations between these behaviours. We therefore examined the ...associations between sleep duration and time spent sitting in adults across five urban regions in Europe.
We used cross‐sectional survey data from 6,037 adults (mean age 51.9 years (SD 16.4), 44.0% men) to assess the association between self‐reported short (<6 h per night), normal (6–8 h per night) and long (>8 h per night) sleep duration with self‐report total time spent sitting, time spent sitting at work, during transport, during leisure and while watching screens. The multivariable multilevel linear regression models were tested for moderation by urban region, age, gender, education and weight status. Because short sleepers have more awake time to be sedentary, we also used the percentage of awake time spent sedentary as an outcome.
Short sleepers had 26.5 min day−1 more sedentary screen time, compared with normal sleepers (CI 5.2; 47.8). No statistically significant associations were found with total or other domains of sedentary behaviour, and there was no evidence for effect modification. Long sleepers spent 3.2% higher proportion of their awake time sedentary compared with normal sleepers.
Shorter sleep was associated with increased screen time in a sample of European adults, irrespective of urban region, gender, age, educational level and weight status. Experimental studies are needed to assess the prospective relation between sedentary (screen) time and sleep duration.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The objective of this study was to explore individual and contextual-level characteristics associated with active (walking and cycling) and public transport as main travel modes for both ...non-commuting and commuting purposes, in residents of five European urban regions. We also described participant-reported motivations for modal choice for each journey purpose. The study used multilevel models to investigate cross-sectional associations of individual (i.e. age, gender, educational level) and contextual (defined by a combination of residential neighbourhood characteristics in typologies) characteristics with the choice of active and public transport as outcome. Based on an online survey of 6037 residents of Ghent and suburbs (Belgium), Paris and inner suburbs (France), Budapest and suburbs (Hungary), the Randstad (including the cities of Amsterdam, Rotterdam, The Hague and Utrecht in the Netherlands) and Greater London (United Kingdom), we observed associations with both individual and contextual characteristics.
Results of the multilevel modelling show that the probability of using active or public transport as main mode varies depending on both individual and contextual characteristics. At individual level, relations with gender, age, education, weight status and having at least one child varied according to main transport mode and/or purpose. For example, overweight participants reported lower level of cycling for commuting and non-commuting travels than normal-weight participants. In the context of non-commuting travels, participants with one or more child reported less public transport use and more walking (vs participants without children). Among contextual-level variables, urban characteristics of the residential neighbourhood defined by four clusters (according to food environment, recreational facilities and active mobility opportunities) were associated with public transport and walking but not with cycling. For active transport the most important reasons were “I like to travel (on foot or by bike)” and “I want to be physically active” for both travel purposes. “Public transport facilities nearby” was indicated as the most important reason for public transport (for both trip purposes) – the second was “Journey time”.
Our findings highlight the importance of exploring a combination of multiple correlates at individual and contextual level according to journey purposes and suggest that the role of health-related individual characteristics such as weight status need further exploration.
•Multilevel approach was used to assess individual/contextual correlates of active and public transport in European regions.•Both individual and contextual characteristics were identified as correlates.•The level of association differed according to trip purposes (commuting vs non-commuting).•For both commuting and non-commuting travels, similar main motivations were observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To explore the associations of absolute and relative measures of exposure to food retailers with dietary patterns, using simpler and more complex measures.
Cross-sectional survey.
Urban regions in ...Belgium, France, Hungary, the Netherlands and the UK.ParticipantsEuropean adults (n 4942). Supermarkets and local food shops were classified as 'food retailers providing healthier options'; fast-food/takeaway restaurants, cafés/bars and convenience/liquor stores as 'food retailers providing less healthy options'. Simpler exposure measures used were density of healthy and density of less healthy food retailers. More complex exposure measures used were: spatial access (combination of density and proximity) to healthy and less healthy food retailers; density of healthier food retailers relative to all food retailers; and a ratio of spatial access scores to healthier and less healthy food retailers. Outcome measures were a healthy or less healthy dietary pattern derived from a principal component analysis (based on consumption of fruits, vegetables, fish, fast foods, sweets and sweetened beverages).
Only the highest density of less healthy food retailers was significantly associated with the less healthy dietary pattern (β = -129·6; 95 % CI -224·3, -34·8). None of the other absolute density measures nor any of the relative measures of exposures were associated with dietary patterns.
More complex measures of exposure to food retailers did not produce stronger associations with dietary patterns. We had some indication that absolute and relative measures of exposure assess different aspects of the food environment. However, given the lack of significant findings, this needs to be further explored.
The National Child Measurement Programme (NCMP) records weight and height and assesses overweight-obesity patterns in English children using body mass index (BMI), which tends to underestimate body ...fatness in South Asian children and overestimate body fatness in Black children of presumed African ethnicity. Using BMI adjustments to ensure that adjusted BMI was similarly related to body fatness in South Asian, Black and White children, we reassessed population overweight and obesity patterns in these ethnic groups in NCMP.
Analyses were based on 2012-2013 NCMP data in 582 899 children aged 4-5 years and 485 362 children aged 10-11 years. Standard centile-based approaches defined weight status in each age group before and after applying BMI adjustments for English South Asian and Black children derived from previous studies using the deuterium dilution method.
Among White children, overweight-obesity prevalences (boys, girls) were 23% and 21%, respectively, in 4-5 year olds and 33% and 30%, respectively, in 10-11 year olds. Before adjustment, South Asian children had lower overweight-obesity prevalences at 4-5 years (19%, 19%) and slightly higher prevalences at 10-11 years (42%, 34%), whereas Black children had higher overweight-obesity prevalences both at 4-5 years (31%, 29%) and 10-11 years (42%, 45%). Following adjustment, overweight-obesity prevalences were markedly higher in South Asian children both at 4-5 years (39%, 35%) and at 10-11 years (52%, 44%), whereas Black children had lower prevalences at 4-5 years (11%, 12%); at 10-11 years, prevalences were slightly lower in boys (32%) but higher in girls (35%).
BMI adjustments revealed extremely high overweight-obesity prevalences among South Asian children in England, which were not apparent in unadjusted data. In contrast, after adjustment, Black children had lower overweight-obesity prevalences except among older girls.
British Heart Foundation, NIHR CLAHRC (South London), NIHR CLAHRC (North Thames).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We performed a systematic literature review on the use of free geospatial services as potential tools to assess built environmental characteristics related to dietary behaviour and physical activity. ...We included 13 studies, all published since 2010 and conducted in urban contexts, with Google Earth and Google Street View as the two main free geospatial services used. The agreement between virtual and field audit was higher for items related to objectively verifiable measures (e.g. presence of infrastructure and equipment) and lower for subjectively assessed items (e.g. aesthetics, street atmosphere, etc.). Free geospatial services appear as promising alternatives to field audit for assessment of objective dimensions of the built environment.
•Built environment has been associated with dietary behaviour and physical activity.•Free geospatial services offer possibilities to assess the built environment.•Our systematic review identified thirteen articles on the topic.•A majority of studies assessed feasibility of virtual audit with free geospatial tools.•Virtual audit offers a reliable method to assess objectively verifiable aspects of the built environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The MW 7.1 Darfield (Canterbury) earthquake, 4 September 2010, generated widespread hydrological effects in New Zealand ranging from instantaneous changes of piezometric levels, to more sustained ...postseismic changes in spring flow, river discharge and groundwater levels, and increased turbidity and declined yields of water ed from wells. Four years later, piezometric levels remained elevated in deeper (>40 m) aquifers along the north‐western (upper) side of the Canterbury Plains near the Greendale Fault, with changes in mean piezometric level reaching +13 m. Linear reservoir modeling (eigen modeling) suggests that sustained high groundwater was not the result of changes in ion or land surface recharge. Step‐drawdown tests at six wells within 15 km of Greendale Fault were carried out prior to the earthquake and were retested following fault rupture. Eden‐Hazel analysis of discharge/drawdown relationships discriminates potential sources of head losses, and how these changed (or otherwise) as a result of the earthquake. Objective application of Eden‐Hazel analysis provided confidence levels for the interpretation, including when step tests provide reliable/unreliable estimates of transmissivity change. Increases in both aquifer losses and well losses were observed in four wells, reflecting both a change in sediment transmissivity and decrease in well efficiency. At two locations, the data were unable to provide results that can be interpreted with confidence. As the majority of local groundwater flow occurs through high‐permeability open framework gravel lenses, we suggest that reduction in the permeability of these gravels, due to fine‐sediment incursion, is the cause of the reduction in transmissivity and increase in well losses.
Key Points:
Piezometric levels showed sustained changes as a result of a Mw 7.1 earthquake
Step testing confirmed a reduction in transmissivity in the region of sustained groundwater rise
It is proposed that pore space in high‐permeability open framework gravels is reduced by fine‐sediment incursion
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The Mam Tor landslide (Derbyshire, England) slips downhill at up to 0.5 m a-1, and offers an excellent opportunity to study time-dependent creep in mudstones under in situ conditions. Annual surveys ...show that creep rates increase following heavy rainfall, but to establish detailed correlation between creep and pore water pressure required spatially and temporally higher resolution monitoring. We acquired 3 years of such data, at 3 h intervals, from wire creep meters, borehole piezometers and rainfall monitoring, showing that creep is strongly focused into the winter months and correlates well with pore water pressure. Summer grass and fern growth strongly influence rainfall infiltration, recycling much of the rainfall back to the atmosphere, explaining the seasonal variability of creep. The dependence of creep rate on pore pressure can be recast as a rheological model relating shear strain rate to shear stress using the friction angle for the creeping mudstone to link effective normal stress to shear stress. The creep is very non-linear, following a power law with a stress exponent of 48. This flow law may apply also to shear failure in poorly consolidated mudrocks under high pore pressure conditions; for example, within some landslides, subglacial sediments, tectonic fault zones, tectonic melanges and accretionary complexes.
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