The Spatial and Temporal Variability of Airborne Pollutants in Stormwater Runoff

Atmospheric deposition is increasingly being recognised as a significant source of total suspended solids (TSS) and heavy metals in urban runoff. However, many uncertainties and challenges remain with measuring and managing these pollutants in runoff. Impermeable concrete boards were deployed in a residential, industrial, and airside land-use area in Christchurch for almost one year in 2013 to determine the spatial and temporal variability of airborne pollutant loads (principally TSS, Cu, Pb, and Zn) in runoff. Results showed that each land-use area displayed similar trends of increasing/decreasing pollutant loads throughout the monitoring period, suggesting that the pollutants originated from a similar source. Consistently higher pollutant loads were found for the industrial area, which was attributed to local topographic conditions rather than land-use activity. All pollutants had a statistically significant relationship with antecedent dry days, illustrating its importance on pollutant build-up. Pollutants dominated by their particulate-phase were influenced by peak rainfall intensity, which was explained by the energy from an intense rainfall event dislodging more particulate pollutants; however, this relationship was weak. Dissolved-phased pollutants displayed a greater relationship to rain depth showing that the quantity of rain influences the dissolution of pollutants from a surface

Beta-amyloid peptide blocks the fast-inactivating K+ current in rat hippocampal neurons

Deposition of beta-amyloid peptide (A beta) in senile plaques is a hallmark of Alzheimer disease neuropathology. Chronic exposure of neuronal cultures to synthetic A beta is directly toxic, or enhances neuronal susceptibility to excitotoxins. Exposure to A beta may cause a loss of cellular calcium homeostasis, but the mechanism by which this occurs is uncertain. In this work, the acute response of rat hippocampal neurons to applications of synthetic A beta was measured using whole-cell voltage-clamp techniques. Pulse application of A beta caused a reversible voltage-dependent decrease in membrane conductance. A beta selectively blocked the voltage-gated fast-inactivating K+ current, with an estimated KI < 10 microM. A beta also blocked the delayed rectifying current, but only at the highest concentration tested. The response was independent of aggregation state or peptide length. The dynamic response of the fast-inactivating current to a voltage jump was consistent with a model whereby A beta binds reversibly to closed channels and prevents their opening. Blockage of fast-inactivating K+ channels by A beta could lead to prolonged cell depolarization, thereby increasing Ca2+ influx

The contribution of wet deposition and particulate matter to total copper, lead and zinc in stormwater runoff

Wet deposition is an important process in the removal of heavy metal particulates from the atmosphere. However, the contribution of wet deposition to the total heavy metal deposition flux can vary widely between different airsheds. Understanding the contribution of wet deposition to the total metal deposition flux is important for accurate knowledge of local atmospheric deposition processes, which will subsequently help in the selection of appropriate stormwater treatment and management options. This research monitored Cu, Zn and Pb loads in wet deposition samples and in bulk deposition samples from modular concrete paving slab systems. In conjunction, ambient particulate matter (PM) concentrations were monitored to determine their contribution to the wet deposition flux. All research was conducted in an industrial land-use area in Christchurch, New Zealand. Results showed that wet deposition efficiently removed PM from the atmosphere, but after 1–2.5 antecedent dry days, PM concentrations recovered. Subsequent antecedent dry days, i.e > 1–2.5 d, did not influence PM concentrations. Pb loads in wet deposition were dependent on coarse PM (size range between 2.5 μm and 10 μm) concentrations. This suggested that there was a local source emitting coarse Pb particles into the atmosphere. Wet deposition was an important contributor of dissolved Zn to bulk deposition. However, dry deposition was the greatest source of total Cu, Zn, and Pb loads in bulk deposition. This is principally due to the low annual rainfall in Christchurch, which limits pollutant removal via wet deposition unlike dry deposition, which is continually occurring

River Invertebrate Classification Tool

Background to research The Regulatory Agencies in the UK (the Environment Agency; Scottish Environment Protection Agency; and the Environment & Heritage Service) currently use RIVPACS III+ software to classify the ecological quality of rivers. However, because RIVPACS III+ pre-dates the WFD, there has been a requirement to ensure that the RIVPACS reference sites are fully WFD compliant, to add new biotic indices to the RIVPACS models, and to improve the robustness of the RIVPACS software to fully meet the needs of the Agencies in their delivery of WFD monitoring. These issues have been addressed in this project and have led to the development of new RIVPACS IV predictive models that will be programmed into a new River Invertebrate Classification Tool being built by SEPA. This new system will be based on a modern software programming language, be compatible with the agencies’ computer systems and include the ability to predict new biological indices, produce biological status assessments based on these new indices and be able to estimate the errors involved in using these new indices. Because access to the new system will be essential for the UK Agencies to be able to implementation the WFD, the new tool will be readily and freely available to anyone who might seek to use it. Objectives of research • The overall objective of the project was to produce a new set of RIVPACS predictive models for use within a new River Invertebrate Classification Tool that will be used to classify the ecological status of rivers for Water Framework Directive compliance monitoring • The new RIVPACS models constructed with this project required considerably enhanced functionality compared to RIVPACS III+ to properly address the monitoring requirements of the UK Agencies in their implementation of the Water Framework Directive. Key findings and recommendations This project has produced new RIVPACS IV models with considerably enhanced functionality compared to RIVPACS III+. These models incorporate: • A full revision of the taxonomic framework of RIVPACS to bring the taxonomy up-to-date and enable compatiability across the revised Miatland, Furse code and National Biodiversity Network taxon coding systems used across the UK Agencies and beyond • Predictions that fully satisfy the WFD definition of ‘reference condition’ by adjusting predictions for certain stream types and by removal of sites that were not in reference condition when sampled • Allocation of actual abundance values to family level records in the RIVPACS reference data set. Lack of actual abundance data, especially at family level, has affected all versions of RIVPACS and has constrained the types of biotic indices that RIVPACS can predict • Extension to the suite of biotic indices so that the new system can predict a wider range of reference state “expected” index values. This enables full WFD quality reporting capabilities as well as providing the system with the general functionality to predict a much wider range of indices e.g. intercalibration indices (e.g. ICMi), stress-specific indices, and ecological and functional trait indices • Extension of the uncertainty/errors module to estimate and assess uncertainty in (i) assignment to status class and (ii) comparison of samples for temporal change in quality and status. This needs to be done for a wider range of biotic indices (including those incorporating abundance data) These new RIVPACS IV models can be used by the UK Agencies across Great Britain and Northern Ireland in their WFD compliance monitoring. All of the algorithms, variables and data necessary to build these models have been provided to SEPA for programming into a new River Invertebrate Classification Tool that will be disseminated made free of charge to all interested user

Design and development of a high precision, high payload telescope dual drive system

A high precision, dual drive system has been designed and developed for the Wide Field Upgrade to the Hobby-Eberly Telescope* at McDonald Observatory in support of the Hobby-Eberly Telescope Dark Energy Experiment‡. Analysis,design and controls details will be of interest to designers of large scale, high precision robotic motion devices. The drive system positions the 19,000 kg star tracker to a precision of less than 5 microns along its 4-meter travel. While positioning requirements remain essentially equal to the existing HET, tracker mass increases by a factor greater than 5. The 10.5-meter long tracker is driven at each end by planetary roller screws, each having two distinct drive sources dictated by the desired operation: one slowly rotates the screw when tracking celestial objects and the second rotates the nut for rapid displacements. Key results of the roller screw rotordynamics analysis are presented. A description of the complex bearing arrangement providing required degrees of freedom as well as the impact of a detailed Failure Modes and Effects Analysis addressing necessary safety systems is also presented. Finite element analysis results demonstrate how mechanical springs increase the telescope's natural frequency response by 22 percent. The critical analysis and resulting design is provided.Center for Electromechanic

Effects of comorbid cardiovascular disease and diabetes on hand osteoarthritis, pain, and functional state transitions: The Johnston county osteoarthritis project

Objective. The purpose of this study is to examine the course of hand osteoarthritis (HOA) and its relationship with cardiovascular disease (CVD) and diabetes (DM). Methods. Data were collected at 3 timepoints from 845 Johnston County Osteoarthritis Project participants (two-thirds women, one-third African Americans, mean age 60 yrs) with and without HOA, CVD, or DM. A diagnosis of radiographic HOA (rHOA) required a Kellgren-Lawrence severity grade of ≥ 2 in at least 3 joints in each hand. A 4-state progressive model included transitions based on rHOA and pain or function as defined using the Australian/Canadian HOA Index (AUSCAN). Markov multistate models estimated HR (aHR) and 95% CI for associations between DM or CVD and specific state transitions, adjusting for baseline and time-varying covariates. Results. Participants with DM (vs those without DM) were more likely to experience worsening pain with rHOA. Individuals who had or developed CVD (vs those who did not) were significantly less likely to experience symptomatic improvement, regardless of rHOA status. Those with DM or CVD (vs those without these comorbidities) were less likely to experience improvement in function, although this was statistically significant only for those with DM and no rHOA. Conclusion. Overall, having or developing DM and/or CVD reduced the likelihood of symptomatic and functional improvement over time, suggesting an effect of comorbid CVD and DM on the clinical and radiographic course of HOA. Additional studies are needed to confirm these findings

Crucial Physical Dependencies of the Core-Collapse Supernova Mechanism

We explore with self-consistent 2D F{\sc{ornax}} simulations the dependence of the outcome of collapse on many-body corrections to neutrino-nucleon cross sections, the nucleon-nucleon bremsstrahlung rate, electron capture on heavy nuclei, pre-collapse seed perturbations, and inelastic neutrino-electron and neutrino-nucleon scattering. Importantly, proximity to criticality amplifies the role of even small changes in the neutrino-matter couplings, and such changes can together add to produce outsized effects. When close to the critical condition the cumulative result of a few small effects (including seeds) that individually have only modest consequence can convert an anemic into a robust explosion, or even a dud into a blast. Such sensitivity is not seen in one dimension and may explain the apparent heterogeneity in the outcomes of detailed simulations performed internationally. A natural conclusion is that the different groups collectively are closer to a realistic understanding of the mechanism of core-collapse supernovae than might have seemed apparent.Comment: 25 pages; 10 figure

Comorbid conditions and the transition among states of hip osteoarthritis and symptoms in a community-based study: A multi-state time-to-event model approach

Background: We examined the association of three common chronic conditions (obesity, diabetes mellitus [DM], and cardiovascular disease [CVD]) with transitions among states of hip osteoarthritis (HOA). Methods: This longitudinal analysis used data from the Johnston County Osteoarthritis Project (JoCo OA, n = 3857), a community-based study in North Carolina, USA, with 18.4 ± 1.5 years of follow-up. Transitions across the following states were modeled: development of radiographic HOA (rHOA; Kellgren-Lawrence grade [KLG] of&lt; 2); development of hip symptoms (self-reported hip pain, aching, or stiffness on most days) or symptomatic HOA (sxHOA; rHOA and symptoms in the same hip), and resolution of symptoms. Obesity (body mass index ≥ 30 kg/m2) and self-reported DM and CVD were the time-dependent comorbid conditions of interest. Markov multi-state models were used to estimate adjusted hazard ratios and 95% confidence intervals to describe the associations between the conditions and HOA states. Results: The sample included 33% African Americans, 39% men, with a mean (SD) age of 62.2 (9.8) years; the frequencies of the comorbidities increased substantially over time. When considered individually, obesity was associated with incident hip symptoms, while CVD and DM were associated with reduced symptom resolution. For those with &gt; 1 comorbidity, the likelihood of incident sxHOA increased, while that of symptom resolution significantly decreased. When stratified by sex, the association between obesity and incident symptoms was only seen in women; among men with DM versus men without, there was a significant (~ 75%) reduction in symptom resolution in those with rHOA. When stratified by race, African Americans with DM, versus those without, were much more likely to develop sxHOA. Conclusions: Comorbid chronic conditions are common in individuals with OA, and these conditions have a significant impact on the persistence and progression of HOA. OA management decisions, both pharmacologic and non-pharmacologic, should include considerations of the inter-relationships between OA and common comorbidities such as DM and CVD

Learning to collaborate: Can young children develop better communication strategies through collaboration with a more popular peer

Unpopular children are known to have poor communication skills and experience difficulty in collaborative situations. This study investigated whether pairing unpopular, 5 to 6 year-old, children with a more popular peer would promote more effective collaboration. The study also investigated differences in popular and unpopular children's verbal and non-verbal communication. Thirty-six girls and 36 boys were placed in one of 12 popular, 12 unpopular or 12 mixed pairs. There were no mixed gender pairs. Children were filmed playing a collaborative game. Collaboration in popular pairs was more successful and less disputational than in unpopular pairs. Boys in unpopular pairs broke the rules of the game more often, argued more and did not monitoring their partners' facial expressions effectively. With popular partners they argued less, were more likely to elaborate disagreements, looked at their partner for longer, smiled more and were more likely to offer him a small toy. Unpopular girls' interactions were not markedly disruptive but they clearly benefited from being paired with a child with good communication skills. Popular girls modified their behaviour to take into account an unpopular partner's need for support. These findings suggest that pairing popular and unpopular children may be a useful classroom organisation strategy

Time resolved photoluminescence study of magnetic CdSe/CdMnS/CdS core/multi-shell nanoplatelets

Colloidal semiconductor nanoplatelets (NPLs) are quasi 2D-nanostructures that are grown and processed inexpensively using a solution based method and thus have recently attracted considerable attention. We observe two features in the photoluminescence spectrum, suggesting two possible recombination channels. Their intensity ratio varies with temperature and two distinct temperature regions are identified; a low temperature region (10K &lt; T &lt; 90K) and a high temperature region (90K &lt; T &lt; 200K). This ratio increases with increasing temperature, suggesting that one recombination channel involves holes that are weakly localized with a localization energy of 0.043meV. A possible origin of these localized states are energy-variations in the xy-plane of the nanoplatelet. The presence of positive photoluminescence circular polarization in the magnetically-doped core/multi-shell NPLs indicates a hole-dopant exchange interaction and therefore the incorporated magnetic Manganese ions act as a marker that determines the location of the localized hole states.1 Time-resolved measurements show two distinct timescales (τfast and τslow) that can be modeled using a rate equation model. We identify these timescales as closely related to the corresponding recombination times for the channels. The stronger hole localization of one of these channels leads to a decreased electron-hole wave function overlap and thus a decreased oscillator strength and an increased lifetime. We show that we can model and understand the magnetic interaction of doped 2D-colloidal nanoplatelets which opens a pathway to solution processable spin controllable light sources. Copyright © 2017 SPIE