The subduction zone in northern Chile is a well‐identified seismic gap that last ruptured in 1877. On 1 April 2014, this region was struck by a large earthquake following a two week long series of ...foreshocks. This study combines a wide range of observations, including geodetic, tsunami, and seismic data, to produce a reliable kinematic slip model of the Mw=8.1 main shock and a static slip model of the Mw=7.7 aftershock. We use a novel Bayesian modeling approach that accounts for uncertainty in the Green's functions, both static and dynamic, while avoiding nonphysical regularization. The results reveal a sharp slip zone, more compact than previously thought, located downdip of the foreshock sequence and updip of high‐frequency sources inferred by back‐projection analysis. Both the main shock and the Mw=7.7 aftershock did not rupture to the trench and left most of the seismic gap unbroken, leaving the possibility of a future large earthquake in the region.
Key Points
A Bayesian ensemble of kinematic slip models is constructed using geodetic, tsunami and seismic data
The earthquake involved a sharp slip zone, more compact than previously thought
The main asperity is located downdip of the foreshock activity and updip of high‐frequency sources
Social interaction with friends is an important contributor to children’s well-being, but how transport affects this is rarely studied. For two or more children (not of the same household) to have ...social interaction where they are physically present (i.e. face-to-face), requires at least one of them to make a trip. Qualitative work has found that children mention the possibility to socialize with friends as a desirable attribute of independent travel, and independent travel is associated with knowing where to find friends. However, little is known quantitatively. Thus, the first objective of this article is to examine whether general travel patterns and licenses to travel independently relate to face-to-face interaction. Further, children in this era have new tools of communication that were not available widely in previous generations. Are those tools being used to replace face-to-face interaction? Thus, a second objective is to examine whether virtual social interaction affects face-to-face social interaction. Next, would it be more likely that replacement would occur if children’s independence was restricted? Which leads to this question, is there any influence of travel patterns and licences on virtual interaction? The findings suggest that virtual social interaction may be complementary to face-to-face interaction and that being allowed to travel independently increases those physically present social interactions.
Previous studies have indicated that factors such as the built environment, attitudes and past behaviour can influence travel behaviour. However, the possible effect of travel satisfaction on travel ...mode choice remains underexplored, despite many studies focusing on travel satisfaction over the past years. It is likely that individuals experiencing satisfying trips with a certain travel mode will use this mode (more) frequently for future trips. In this study—using data from 984 students from Laval University, Canada—we analyse how satisfaction with public transport and the frequency of public transport use affect the intention to use public transport in later life stages. Our results indicate that public transport frequency, public transport satisfaction and the interaction between these two factors (i.e., the frequency of (dis)satisfying public transport trips) significantly affect people’s intentions to use public transport in later life, although variations in effect sizes exist between different life stages. Making public transport more pleasant and increasing ridership of children and young adults (e.g., by giving them free public transport passes) may consequently result in a higher public transport frequency in later life stages. We argue that travel satisfaction can play an important role in the formation of habitual mode use, and that satisfying trips (if undertaken frequently) are likely to be repeated in the future.
Monitoring access to drinking water is complex, especially in settings where on premises water supply is not available. Although self-reported data are generally used to estimate coverage of access ...to drinking water, the relationship between self-reported time travelled and true time travelled is not well known in the context of water fetching. Further, water fetching is likely to impact the quantity and quality of water a household uses, but data and measures supporting this relationship are not well documented. The objective of this study was to appraise the validity and reliability of self-reported measurements used to estimate access coverage. A case study was conducted in Malawi to enhance understanding of the self-reported measures and alternatives available to assess and monitor access to drinking water in view of generating global estimates. Self-reported data were compared with objective observations and direct measurements of water quantity, quality and accessibility. Findings from this study highlight the variations between different measures such as self-reported and recorded collection time and raise awareness with regard to the use of self-reported data in the context of fetching water. Alternatives to self-reported indicators such as GPS-based or direct observations could be considered in surveys in view of improving data accuracy and global estimates.
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•Easily replicable measures are available to monitor access to drinking water.•Household perception is a reliable indicator for microbial quality at the water source.•Euclidean distance is more reliable than self-reported collection time.•Queue time is an ambiguous measure that should be integrated with caution.•Alternatives to self-reported measures could improve global estimates.
The COVID-19 pandemic disrupted travel behaviours for very large numbers of people including those who shifted to teleworking and those without the option to work from home. While there is much ...valuable transport research that has examined the former category, it is still unknown how certain people such as health sector employees and delivery drivers changed their physical commuting in transport contexts that were radically different from those existing normally in urban areas. Based on a systematic review of 36 scientific publications on commuting during pandemic, this study pursues a dual objective. First, by examining the interrelated institutional, physical, and socio-psychological processes that supported or hindered low-carbon transport the study revealed that (A) public transport (PT) reduced service levels and concerns related to COVID were positively associated with substantial shifts away from PT towards car and active travel; (B) this positive association was found to be even stronger in the existence of pre-pandemic habit of car use for commute and strong negative emotions like fear triggered by environmental changes and health risks. Second, by synthesising the key findings from the literature, this study provides significant implications for how mode choice is modelled through the Theory of Planned Behavior and Norm Activation Model. By questioning whether the pandemic commuters had a "normal" set of travel mode alternatives to choose from, the study draws attention to the nuances of mode "choice" versus mode "use" and moves beyond the assumption that commuting always results from individuals making choices. It also argues that the role of (negative) emotions along with the importance of proximity to, or separation from, other bodies on how people commute should be considered in future research. Finally, the crucial role of COVID-19 in changing travel-related norms and the resulting long-term implications for policy interventions require further investigation by future research.
Abstract
We present a simple model for low-mass planet formation and subsequent evolution within ‘transition’ discs. We demonstrate quantitatively that the predicted and observed structures of such ...discs are prime birthsites of planets. Planet formation is likely to proceed through pebble accretion, should a planetary embryo (M ≳ 10−4 M⊕) form. Efficient pebble accretion is likely to be unavoidable in transition disc dust traps, as the dust particles required for pebble accretion are those which are most efficiently trapped in the transition disc dust trap. Rapid pebble accretion within the dust trap gives rise not only to low-mass planets, but also to a large accretion luminosity. This accretion luminosity is sufficient to heat the disc outside the gravitational influence of the planet and makes the disc locally baroclinic, and a source of vorticity. Using numerical simulations, we demonstrate that this source of vorticity can lead to the growth of a single large-scale vortex in ∼100 orbits, which is capable of trapping particles. Finally, we suggest an evolutionary cycle: Planet formation proceeds through pebble accretion, followed by vortex formation and particle trapping in the vortex quenching the planetary accretion and thus removing the vorticity source. After the vortex is destroyed, the process can begin anew. This means transition discs should present with large-scale vortices for a significant fraction of their lifetimes, and remnant planets at large 10 au radii should be a common outcome of this cycle.
•Self-reported emotional states during the pandemic, among Canadian children and youth, were explored.•Latent Class Analysis shows 49.4% sample displayed patterns of low subjective well-being.•Having ...access to friends, and indoor and outdoor spaces/places to play and exercise, were important.•Decreased physical activity and increased screen time were associated with a low SWB during the pandemic.
The current COVID-19 pandemic has disrupted daily behaviours of children and youth. Yet, little is known about how they are mentally coping with the pandemic-time changes to their lives. This study explores children and youths’ self-reported subjective well-being (SWB) during the pandemic, and provides novel insights into the correlates of potential decrease, using data from a pan-Canadian online survey of 932 children/youth and their parents. SWB was measured based on perceived changes in 12 affective/emotional states. The results indicate that in spring 2020, at the height of the first wave of the pandemic, many children and youth were more bored (37.6%) and worried (31%) compared to pre-pandemic time. At the same time, many self-reported that they felt calmer (31.9%) and more rested (30%). A latent class analysis revealed that nearly half (49.4%) of surveyed children and youth reported patterns in changes in their emotional state that may contribute to lower SWB. Results from binomial logistic regression suggest that socio-demographic characteristics and size of the municipality were not associated with low pandemic-time SWB. Instead, other potentially modifiable factors such as having access to friends, indoor and outdoor spaces/places to play and exercise, and healthy movement behaviours during the pandemic, were correlated with a lower likelihood of reporting low SWB. The findings can inform pandemic-time public health policy relating to physical distancing, and in the longer term, mental and physical health promotion. The results will also help improve urban planning and design practices in creating healthier, more resilient and equitable communities.
Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on ...hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ~0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R sub(+ in circle). Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ~0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M sub(+ in circle) and the majority of them should have core masses of a few Earth masses.
•Post collection contamination poses greater risk in the rainy season than the dry season.•Water sources that are initially free from contamination are subject to further degradation.•Use of distinct ...containers for collection and storage reduced the level of risk of contamination.•Households are more likely to over-report what they consider good practices in accessing water.•Self-reported or observed data are complementary methods to identify household practices.
Lack of access to safe drinking water on premises remains widespread in low- and middle-income countries. Interventions to improve access to safe water at the point of collection are essential, but water safety at the point of consumption is also an important consideration. This research aimed to 1) improve understanding of household practices in collecting water with respect to seasonality, and 2) to further assess risk associated with post-collection contamination from the point of collection to the point of consumption. A seasonal cohort study, including 115 households, was conducted in Malawi. Along with household surveys and observations, samples of water were tested for microbial water quality at four different stages of water collection: water source, collection container, storage container, cup of drinking water. Using E. coli as an indicator of contamination (cfu/100 ml), the risk of post-collection contamination was assessed. The results indicate that most water sources were free from contamination; contamination was proportionally lower in the dry season when more sources were found to be classified as having a very low risk of contamination. However, the level of risk of contamination was more likely to increase following collection in water sources that were initially free from contamination. Results show that the degradation in water quality from the point of collection to the point of consumption was more important in the rainy season, which is likely to be driven by the effect of seasonality on the household environment. Filling the collection container at the point of collection and storage at the point of consumption were found to be critical stages for an increased risk of E. coli contamination. Understanding household practices in accessing and handling water during both rainy and dry season is necessary to target appropriate interventions to reduce post-collection contamination.
Congenital cytomegalovirus (cCMV) infection remains a leading cause of childhood hearing loss. Currently universal CMV screening at birth does not exist in the United States. An alternative approach ...could be testing infants who do not pass their newborn hearing screening (NHS) for cCMV. This study was undertaken to evaluate whether a targeted approach will identify infants with CMV-related sensorineural hearing loss (SNHL).
Infants born at 7 US medical centers received NHS and were also screened for cCMV while in the newborn nursery. Infants who tested positive for CMV received further diagnostic audiologic evaluations to identify or confirm hearing loss.
Between 2007 and 2012, 99 945 newborns were screened for both hearing impairment and cCMV. Overall, 7.0% of CMV-positive infants did not pass NHS compared with 0.9% of CMV-negative infants (P < .0001). Among the cCMV infants who failed NHS, diagnostic testing confirmed that 65% had SNHL. In addition, 3.6% of CMV-infected infants who passed their NHS had SNHL confirmed by further evaluation during early infancy. NHS in this cohort identified 57% of all CMV-related SNHL that occurred in the neonatal period.
A targeted CMV approach that tests newborns who fail their NHS identified the majority of infants with CMV-related SNHL at birth. However, 43% of the infants with CMV-related SNHL in the neonatal period and cCMV infants who are at risk for late onset SNHL were not identified by NHS.
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