The dynamism of salt crust patterns on playas

Playas are common in arid environments and can be major sources of mineral dust that can influence global climate. These landforms typically form crusts that limit evaporation and dust emission, modify surface erosivity and erodibility, and can lead to over prediction or under prediction of (1) dust-emission potential and (2) water and heat fluxes in energy balance modeling. Through terrestrial laser scanning measurements of part of the Makgadikgadi Pans of Botswana (a Southern Hemisphere playa that emits significant amounts of dust), we show that over weeks, months, and a year, the shapes of these surfaces change considerably (ridge thrusting of >30 mm/week) and can switch among continuous, ridged, and degraded patterns. Ridged pattern development changes the measured aerodynamic roughness of the surface (as much as 3 mm/week). The dynamic nature of these crusted surfaces must be accounted for in dust entrainment and moisture balance formulae to improve regional and global climate models

The Evolving Role of Youth Workers

In reviewing the field of youth development, of which youth workers are a part, it is clear it has had a long and complex history that is intertwined with other disciplines. More recently youth workers have experienced a transformation of sorts, with youth programs in the past being seen exclusively as a place to play and have fun, whereas today’s expectations include a much broader focus on the overall positive development of young people. This evolution has been heavily influenced by a number of societal changes that have placed increasing demands on youth programs. Today’s youth workers are faced with the responsibility to promote a young person’s development which often includes supporting academic success and graduation from high school, reducing risk-taking behaviors, increasing positive health attitudes, and more. Youth workers have seen their role change dramatically over the past 20 years with greater demands and increased accountability

The Evolving Role of Youth Workers

In reviewing the field of youth development, of which youth workers are a part, it is clear it has had a long and complex history that is intertwined with other disciplines. More recently youth workers have experienced a transformation of sorts, with youth programs in the past being seen exclusively as a place to play and have fun, whereas today’s expectations include a much broader focus on the overall positive development of young people. This evolution has been heavily influenced by a number of societal changes that have placed increasing demands on youth programs. Today’s youth workers are faced with the responsibility to promote a young person’s development which often includes supporting academic success and graduation from high school, reducing risk-taking behaviors, increasing positive health attitudes, and more. Youth workers have seen their role change dramatically over the past 20 years with greater demands and increased accountability

Attention-deficit/hyperactivity disorder medication and seizures

OBJECTIVE: Individuals with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of seizures, but there is uncertainty about whether ADHD medication treatment increases risk among patients with and without preexisting seizures. METHODS: We followed a sample of 801,838 patients with ADHD who had prescribed drug claims from the Truven Health MarketScan Commercial Claims and Encounters databases to examine whether ADHD medication increases the likelihood of seizures among ADHD patients with and without a history of seizures. First, we assessed overall risk of seizures among patients with ADHD. Second, within-individual concurrent analyses assessed odds of seizure events during months when a patient with ADHD received ADHD medication compared with when the same individual did not, while adjusting for antiepileptic medications. Third, within-individual long-term analyses examined odds of seizure events in relation to the duration of months over the previous 2 years patients received medication. RESULTS: Patients with ADHD were at higher odds for any seizure compared with non-ADHD controls (odds ratio [OR] = 2.33, 95% confidence interval [CI] = 2.24-2.42 males; OR = 2.31, 95% CI = 2.22-2.42 females). In adjusted within-individual comparisons, ADHD medication was associated with lower odds of seizures among patients with (OR = 0.71, 95% CI = 0.60-0.85) and without (OR = 0.71, 95% CI = 0.62-0.82) prior seizures. Long-term within-individual comparisons suggested no evidence of an association between medication use and seizures among individuals with (OR = 0.87, 95% CI = 0.59-1.30) and without (OR = 1.01, 95% CI = 0.80-1.28) a seizure history. CONCLUSIONS: Results reaffirm that patients with ADHD are at higher risk of seizures. However, ADHD medication was associated with lower risk of seizures within individuals while they were dispensed medication, which is not consistent with the hypothesis that ADHD medication increases risk of seizures

Decoupling the World Wide Web From Linked Lists in I/O Automata

E-business must work. After years of structured research into information retrieval systems, we argue the emulation of checksums. We propose new stable technology, which we call ILIUM

Early-stage aeolian protodunes: bedform development and sand transport dynamics

Early-stage aeolian bedforms, or protodunes, are elemental in the continuum of dune development and act as essential precursors to mature dunes. Despite this, we know very little about the processes and feedback mechanisms that shape these nascent bedforms. Whilst theory and conceptual models have offered some explanation for protodune existence and development, until now, we have lacked the technical capability to measure such small bedforms in aeolian settings. Here, we employ terrestrial laser scanning to measure morphological change at the high frequency and spatial resolution required to gain new insights into protodune behaviour. On a 0.06 m high protodune, we observe vertical growth of the crest by 0.005 m in two hours. Our direct measurements of sand transport on the protodune account for such growth, with a reduction in time-averaged sediment flux of 18% observed over the crestal region. Detailed measurements of form also establish key points of morphological change on the protodune. The position on the stoss slope where erosion switches to deposition is found at a point 0.07 m upwind of the crest. This finding supports recent models that explain vertical dune growth through an upwind shift of this switching point. Observations also show characteristic changes in the asymmetric cross section of the protodune. Flow-form feedbacks result in a steepening of the lee slope and a decline in lower stoss slope steepness (by 3°), constituting a reshaping of protodune form towards more mature dune morphology. The approaches and findings applied here, a) demonstrate an ability to quantify processes at requisite spatial and temporal scales for monitoring early-stage dune evolution, b) highlight the crucial role of form-flow feedbacks in enabling early-stage bedform growth, alluding to a fluctuation in feedbacks that require better representation in dune models, and c) provide a new stimulus for advancing understanding of aeolian bedforms

Coupling leeside grainfall to avalanche characteristics in aeolian dune dynamics

Avalanche (grainflow) processes are fundamental drivers of dune morphodynamics and are typically initiated by grainfall accumulations. In sedimentary systems, however, the dynamism between grainfall and grainflow remains unspecified because simple measurements are hampered by the inherent instability of lee slopes. Here, for the first time, terrestrial laser scanning is used to quantify key aspects of the grainfall process on the lee (slip face) of a barchan sand dune. We determine grainfall zone extent and flux and show their variability under differing wind speeds. The increase in the downwind distance from the brink of peak grainfall under stronger winds provides a mechanism that explains the competence of large avalanches to descend the entire lee slope. These findings highlight important interactions between wind speed, grainfall, and subsequent grainflow that influence dune migration rates and are important for correct interpretation of dune stratigraphy

Engaging Youth in Evaluation: Using Clickers for Data Collection

Now, more than ever, evaluation is an essential component for all programs. Although the need for outcome data is clear, collecting data from youth populations is often difficult, particularly among youth who are vulnerable and/or disenfranchised. While the use of paper-and-pencil (PAP) surveys is a commonly used method of data collection, different technological methods, such as online surveys, text messaging, and personal digital assistants (PDA’s), are increasingly employed in data collection efforts. This article explores the use of audience response systems (“clickers”) as an innovative data collection method that is especially suited for use with youth. In this paper we examine qualitative findings from key informant interviews regarding data collected from youth participants on a youth program quality measure using clicker technology. Findings from the study indicate that the use of clickers may increase youth engagement in and improve the efficiency of the data collection process

Maternal mind-mindedness: stability over time and consistency across relationships

Maternal mind-mindedness has been described both as a cognitive-behavioural trait and as a relational construct. This study assessed stability over time and consistency across relationships of maternal mind-mindedness in relation to preschool and primary school siblings and compared representational and interactional mind-mindedness. Mothers with two children between 2½ and 10 years were assessed twice, nine months apart (N = 32 at Time 1; N = 30 at Time 2). Representational mind-mindedness for a partner/friend was also assessed twice. Mothers’ representational mind-mindedness showed temporal stability but was inconsistent across relationships with two children and a partner/friend. Conversely, mothers’ interactional mind-mindedness was stable and highly consistent across relationships with two children. This supports the possibility that mothers’ interactional mind-mindedness is trait-like, while findings are equivocal for representational mind-mindedness. Representational mind-mindedness and interactional mind-mindedness were unrelated in this preliminary study, suggesting that these measures of maternal mind-mindedness were not equivalent for this age group

Parent Report and Actigraphically Defined Sleep in Children with and without Developmental Coordination Disorder; Links with Fatigue and Sleepiness

Background: Impaired sleep is associated with negative effects on quality of life and daytime functioning. Higher rates of sleep disturbance are reported in children with various developmental disorders. However, little is known about sleep in children with developmental coordination disorder (DCD), a condition characterized by everyday movement difficulties. Previously, in a preliminary study, we found higher rates of parent-reported sleep disturbance in children with DCD compared to controls. Aims: To examine sleep in DCD using objective measures and to examine links with daytime fatigue and sleepiness. Methods: Two groups (primary and secondary school-aged) of 15 children with DCD, plus matched controls, participated. Parent-reported child sleep was assessed using the Children’s Sleep Habits Questionnaire and actigraphy provided an objective measure of sleep–wake patterns over 1 week (including weekdays and weekend). Pediatric restless legs syndrome (RLS) semi-structured diagnostic interview was conducted with each child and parent to capture symptoms of RLS. Aspects of self-rated child functioning were assessed with questionnaires (Pre-sleep Arousal Scale, Pediatric Daytime Sleepiness Scale, PedsQL Multidimensional Fatigue Scale) and mothers’ reported thoughts about child sleep with the Maternal Cognitions about Infant Sleep Questionnaire. Results: The DCD groups had greater parent-reported sleep disturbance. Actigraphy results suggested that for secondary aged children with DCD their sleep quality was impaired and there were differences in the timing of sleep compared to controls (including some differences in the variation between weekday and weekend sleep times). The actigraphy of the primary age group with DCD was unremarkable compared to controls. No child in the study met the criteria for RLS. Exploratory analyses suggested that daytime fatigue, aspects of pre-sleep arousal, and daytime sleepiness were reported as greater in the DCD groups and were particularly related to objective sleep parameters in the DCD groups. Maternal thoughts about sleep did not differ between the DCD and control groups. Conclusion: The nature and underlying cause of sleep disturbance and how it might be linked with aspects of daytime functioning in adolescents with DCD requires further research. Meanwhile, clinical awareness of the risk of atypical sleep patterns/sleep problems in DCD is important to ensure early identification and implementation of appropriate support