654 research outputs found
Critical dependence of morphodynamic models of fluvial and tidal systems on empirical downslope sediment transport
The morphological development of fluvial and tidal systems is forecast more and more frequently by models in scientific and engineering studies for decision making regarding climate change mitigation, flood control, navigation and engineering works. However, many existing morphodynamic models predict unrealistically high channel incision, which is often dampened by increased gravity-driven sediment transport on side-slopes by up to two orders of magnitude too high. Here we show that such arbitrary calibrations dramatically bias sediment dynamics, channel patterns, and rate of morphological change. For five different models bracketing a range of scales and environments, we found that it is impossible to calibrate a model on both sediment transport magnitude and morphology. Consequently, present calibration practice may cause an order magnitude error in either morphology or morphological change. We show how model design can be optimized for different applications. We discuss the major implications for model interpretation and a critical knowledge gap
The Duodenum harbors a Broad Untapped Therapeutic Potential
The gastroenterologist, when performing an esophagogastroduodenoscopy, is the only medical care provider with easy access to the duodenum (Figure 1A). This simple fact is pivotal in this article that discusses why the duodenum has become such an important anatomic region of interest. Recent insights have revealed the critical physiologic and pathophysiologic role of the small bowel in metabolic homeostasis and its potential role as a driver of obesity, insulin resistance, and subsequent type 2 diabetes mellitus (T2DM). Although the other parts of the small bowel cannot be ignored when describing the potential mechanisms involved in the development of metabolic diseases and T2DM, the excellent endoscopic accessibility of the duodenum makes it a prime target for disease-modifying intervention
Prevalence and Risk Factors for Delirium in Elderly Patients With Severe Burns: A Retrospective Cohort Study
Little is known about delirium in elderly burn center patients. The aim of this study is to provide information on the prevalence of delirium and risk factors contributing to the onset of delirium. All patients aged 70 years or older admitted with burn injuries to the Burn Center, Maasstad Hospital, in 2011 to 2017 were eligible for inclusion. We retrospectively collected data regarding the presence of delirium, potential risk factors contributing to the onset of delirium and outcome after delirium. We included elderly 90 patients in this study. The prevalence of delirium in our population was 13% (N = 12). Risk factors for delirium were advanced age, increased American Society for Anesthesiologists score, physical impairment and the use of anticholinergic drugs during admission. Patients with delirium had a poorer outcome, with prolonged hospital stay and increased mortality 6 and 12 months after discharge. Delirium is diagnosed in 13% of the elderly patients admitted to our burn center. Risk factors for delirium found in this study are advanced age, poor physical health status, physical impairment, and the use of anticholinergic drugs. Delirium is related to poor outcomes, including prolonged hospital stay and mortality after discharge
Observing mother-child interaction in a free-play vs. a structured task context and its relationship with preterm and term born toddlers' psychosocial outcomes
IntroductionHigh quality of mother-child interaction is associated with better psychosocial outcomes in children. However, this association might depend on the context in which mother-child interaction is observed as well as specific child characteristics. In this study, we examine differences in the assessment of mother-child interaction in a free-play and a structured task context. In addition, it will be investigated whether the behaviors per context are differently associated with preterm vs. term born toddlers' psychosocial outcomes.MethodsA total of 201 Dutch mother-child dyads participated in the study, of whom 108 children were moderate to late preterm (MLP) and 93 were born at term. Mother-child interaction was observed in a free-play and a structured task context when the child was 18 months of (corrected) age. Six subscales of mother-child interaction were assessed using the Coding Interactive Behavior scheme: maternal stimulation, maternal warmth, child's negative affect, active mother and child engagement, dyadic synchrony and tense interaction. Psychosocial outcomes were assessed at 24 months of (corrected) age using the Ages and Stages Questionnaire – Social Emotional and the Child Behavior Checklist.ResultsMother-child interaction was reliably assessed (α > .60) in each context, except for tense interaction during free-play (α = .41) and child's negative affect when averaged across contexts (α = 0.55). Compared to the free-play context, during the structured task, more child's negative affect, tense interaction and active mother and child engagement was observed in MLP and term born children, and less dyadic synchrony in MLP children (p's < .01). Only during a structured task and for term born children, active mother and child engagement was related to less social-emotional difficulties, internalizing and externalizing behaviors. Only during free-play and for MLP children, active mother and child engagement was related to less externalizing behaviors. Dyadic synchrony during a structured task was associated with less social-emotional difficulties in MLP and term born children, and dyadic synchrony during free-play was only associated with less social-emotional difficulties in term born children (all p's < .05).DiscussionMost mother-child interactive behaviors can be reliably assessed in both contexts. The structured task context elicited more varied behaviors than the free-play context. With the observations in the structured task context, more associations with children's psychosocial outcomes were found than with the observations in the free-play context. Mother-child interactions characterized by active, engaged and synchronous behaviors were associated with better psychosocial outcomes in toddlers, with some differences observed for MLP vs. term born children and for the free-play vs. the structured task context. Suggestions for future research as well as clinical practice are provided
Is maternal negative affectivity related to psychosocial behavior of preterm and term-born toddlers through mother–child interaction?
Introduction: Children born moderately to late preterm (MLP) are more prone to psychosocial difficulties than their term-born counterparts. Maternal negative affectivity (NA)–a relatively stable personality trait characterized by the tendency to experience negative thoughts, feelings and emotions–has been related to more psychosocial problems in their offspring, and to a lower quality of mother–child interactions. As MLP children seem more sensitive to their early caregiving environment, they might be more affected by maternal NA and interaction style than their term-born peers. The current study investigated whether maternal NA predicted child’s psychosocial outcomes through quality of mother–child interaction, and if these associations differed between MLP and term-born children. Methods: The sample consisted of 108 MLP and 92 term-born children and their mothers. At 18 months corrected age, maternal NA was measured using a self-report questionnaire and mother–child interaction was observed during two structured tasks. Five subscales of mother–child interaction were assessed: negative interaction, reciprocal engagement, emotional support, maternal stimulation and mother-led interaction. At 24 months corrected age, social–emotional difficulties, internalizing, and externalizing problems were assessed using mother-report. Results: For MLP children, maternal NA directly, positively, predicted social–emotional difficulties (b = 0.57) and internalizing problems (b = 0.45), but no mediation effect of mother–child interaction was found. For term-born children, no direct effect but a mediation effect of mother-led interaction was found. Higher levels of maternal NA predicted less mother-led interaction which in turn predicted more problems. Birth status did not moderate any of the relationships, showing that the differences in patterns of effects found within the MLP and term-born group did not reach statistical significance. Discussion: Maternal NA was found to be a risk factor for psychosocial outcomes in toddlers, either directly for MLP children or indirectly through mother-led interaction for term-born children. These findings suggest that the process through which maternal NA affects psychosocial outcomes may be different for MLP and term-born children. However, as the examined moderation effects of birth status did not reach statistical significance, more research using larger sample sizes is needed to study mother–child interaction in greater detail
Haptic Shared Control in Tele-Manipulation: Effects of Inaccuracies in Guidance on Task Execution
Haptic shared control is a promising approach to improve tele-manipulated task execution, by making safe and effective control actions tangible through guidance forces. In current research, these guidance forces are most often generated based on pre-generated, errorless models of the remote environment. Hence such guidance forces are exempt from the inaccuracies that can be expected in practical implementations. The goal of this research is to quantify the extent to which task execution is degraded by inaccuracies in the model on which haptic guidance forces are based. In a human-in-the-loop experiment, subjects (n = 14) performed a realistic tele-manipulated assembly task in a virtual environment. Operators were provided with various levels of haptic guidance, namely no haptic guidance (conventional tele-manipulation), haptic guidance without inaccuracies, and haptic guidance with translational inaccuracies (one large inaccuracy, in the order of magnitude of the task, and a second smaller inaccuracy). The quality of natural haptic feedback (i.e., haptic transparency) was varied between high and low to identify the operator\u27s ability to detect and cope with inaccuracies in haptic guidance. The results indicate that haptic guidance is beneficial for task execution when no inaccuracies are present in the guidance. When inaccuracies are present, this may degrade task execution, depending on the magnitude and the direction of the inaccuracy. The effect of inaccuracies on overall task performance is dominated by effects found for the Constrained Translational Movement, due to its potential for jamming. No evidence was found that a higher quality of haptic transparency helps operators to detect and cope with inaccuracies in the haptic guidance.</p
eCorrelates of prenatal and postnatal mother-to-infant bonding quality:A systematic review
Background Mother-to-infant bonding is defined as the emotional tie experienced by a mother towards her child, which is considered to be important for the socio-emotional development of the child. Numerous studies on the correlates of both prenatal and postnatal mother-to-infant bonding quality have been published over the last decades. An up-to-date systematic review of these correlates is lacking, however. Objective To systematically review correlates of prenatal and postnatal mother-to-infant bonding quality in the general population, in order to enable targeted interventions. Methods MEDLINE, Embase, CINAHL, and PsychINFO were searched through May 2018. Reference checks were performed. Case-control, cross-sectional or longitudinal cohort studies written in English, German, Swedish, Spanish, Norwegian, French or Dutch defining mother-to-infant bonding quality as stipulated in the protocol (PROSPERO CRD42016040183) were included. Two investigators independently reviewed abstracts, full-text articles and extracted data. Methodological quality was assessed using the National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-sectional studies and was rated accordingly as poor, fair or good. Clinical and methodological heterogeneity were examined. Main results 131 studies were included. Quality was fair for 20 studies, and poor for 111 studies. Among 123 correlates identified, 3 were consistently associated with mother-to-infant bonding quality: 1) duration of gestation at assessment was positively associated with prenatal bonding quality, 2) depressive symptoms were negatively associated with postnatal mother-to-infant bonding quality, and 3) mother-to-infant bonding quality earlier in pregnancy or postpartum was positively associated with mother-to-infant bonding quality later in time. Conclusion Our review suggests that professionals involved in maternal health care should consider monitoring mother-to-infant bonding already during pregnancy. Future research should evaluate whether interventions aimed at depressive symptoms help to promote mother-toinfant bonding quality. More high-quality research on correlates for which inconsistent results were found is needed
Morphological effects of vegetation on the tidal-fluvial transition in Holocene estuaries
Vegetation enhances bank stability and sedimentation to such an extent that it can modify river patterns, but how these processes manifest themselves in full-scale estuarine settings is poorly understood. On the one hand, tidal flats accrete faster in the presence of vegetation, reducing the flood storage and ebb dominance over time. On the other hand flow-focusing effects of a tidal floodplain elevated by mud and vegetation could lead to channel concentration and incision. Here we study isolated and combined effects of mud and tidal marsh vegetation on estuary dimensions. A 2-D hydromorphodynamic estuary model was developed, which was coupled to a vegetation model and used to simulate 100 years of morphological development. Vegetation settlement, growth and mortality were determined by the hydromorphodynamics. Eco-engineering effects of vegetation on the physical system are here limited to hydraulic resistance, which affects erosion and sedimentation pattern through the flow field. We investigated how vegetation, combined with mud, affects the average elevation of tidal flats and controls the system-scale planform. Modelling with vegetation only results in a pattern with the largest vegetation extent in the mixed-energy zone of the estuary, which is generally shallower. Here vegetation can cover more than 50 % of the estuary width while it remains below 10 %–20 % in the outer, tide-dominated zone. This modelled distribution of vegetation along the estuary shows general agreement with trends in natural estuaries observed by aerial image analysis. Without mud, the modelled vegetation has a limited effect on morphology, again peaking in the mixed-energy zone. Numerical modelling with mud only shows that the presence of mud leads to stabilisation and accretion of the intertidal area and a slight infill of the mixed-energy zone. Combined modelling of mud and vegetation leads to mutual enhancement with mud causing new colonisation areas and vegetation stabilising the mud. This occurs in particular in a zone previously described as the bedload convergence zone. While vegetation focusses the flow into the channels such that mud sedimentation in intertidal side channels is prevented on a timescale of decades, the filling of intertidal area and the resulting reduction in tidal prism may cause the infilling of estuaries over centuries
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