Potential Buildup Research Articles

Uncertainty-based parameter estimation for urban pollutant buildup and washoff simulation using a multiple pattern inverse modeling approach

Reliable model parameter estimation for stormwater runoff water quality modeling has always been a challenge, especially in ungauged areas. Insufficient local observations can increase parameter uncertainty, leading to modeling outputs of limited credibility. This paper proposes an event-based multiple pattern inverse modeling approach to estimate regional-scale parameters characterizing the buildup and washoff processes in urban watersheds. The approach explicitly accounts for system uncertainties by simultaneously using a wide range of storm events. A genetic algorithm was employed to solve the inverse models. The solution populations that minimize the error between the observed and predicted values were then filtered into distinct parameter groups using a K-means clustering algorithm. Each identified parameter group may be used to represent the buildup and washoff processes.The proposed approach was applied for the New England region (United States) using two study sites with impervious land cover: Massachusetts and New Hampshire. Stormwater monitoring data of total nitrogen (TN) and total phosphorus (TP) in small to medium size rainfall events were used to identify representative parameter sets for the region. Of the 21 identified candidate parameter combinations, 13 were found to have acceptable Root Mean Square Error for both TN and TP.The 13 parameter sets were grouped into four distinct patterns to represent different potential buildup and washoff mechanisms. The results demonstrate that the approach is capable of estimating robust sets of buildup and washoff parameters at a regional scale. These can be used in a continuous simulation model to predict TN and TP loads in ungauged areas in the region.

A Mathematical Model Relating Pitocin Use during Labor with Offspring Autism Development in terms of Oxytocin Receptor Desensitization in the Fetal Brain.

This paper develops a mathematical model describing the potential buildup of high oxytocin concentrations in the maternal circulation during labor in terms of continuous Pitocin infusion rate, half-life, and maternal weight. Oxytocin override of the degradation of oxytocin by placental oxytocinase is introduced to model the potential transfer of oxytocin from the maternal circulation across the placenta into the fetal circulation and from there into the brain of the fetus. The desensitization unit D equal to 1.8E6 (pg·min)/ml is employed to establish a desensitization threshold and by extension, a downregulation threshold as a function of oxytocin override concentration and continuous Pitocin infusion time, that could be a factor in the subsequent development of autism among offspring. Epidemiological studies by Duke University [1], Yale University [2], and Harvard University [3] are discussed regarding Pitocin use and offspring autism development for an explanation of the weak correlations they identified. The findings of the Harvard epidemiological study are reinterpreted regarding Pitocin use and its conclusion questioned. Further evaluations of the findings of these three epidemiological studies are called for to incorporate medical information on quantity of Pitocin used, continuous Pitocin infusion rate, length of labor, and maternal weight to determine if a correlation can be established with offspring autism development above an empirically determined desensitization threshold for Pitocin use. Suggestions for research are discussed, including an alternative to continuous Pitocin infusion, pulsatile infusion of Pitocin during labor induction, which may mitigate possible offspring autism development.

Potential Profile Measurements Inside a Gridded Cathode at High Potential in a Spherical Inertial Electrostatic Confinement Device

This paper proposes a Langmuir probe–based diagnostics for plasma parameters inside gridded cathodes at high bias potentials in inertial electrostatic confinement devices. As the first step for the proof of concept, floating potential profiles were measured in deuterium and helium plasmas in a glow-discharge mode. The measurements with fusion-relevant cathode voltages up to 55 kV were carried out successfully. The results revealed that the positive potential buildup at the center ranges from 5% to 8% of the applied bias voltage to the gridded cathode, which is found to be much smaller than those in earlier works under cathode voltages lower than 5 kV. It was also shown that the floating potential profile is different significantly between deuterium and helium discharge plasmas.

Abstract #27: Modeling the Physiological Effects of Burst Stimulation: Influence of Active vs. Passive Recharge Phases

Introduction: Burst stimulation patterns consist of packets of relatively high frequency stimulation pulses repeated over time at lower frequencies and have produced promising outcomes when used with spinal cord stimulation (SCS) to treat neuropathic pain. A recent hypothesis proposes that the passive or active nature of the burst waveform recharge phase may influence outcomes due to the “postsynaptic non-linear buildup of the super-action potential” by passive recharge burst (De Ridder, commentary in Neuromodulation, 2017), but this hypothesis has not been proven. The aim of this study is to use computational modeling to discern differences between physiological effects in the activation of dorsal columns (DC), such as axon activation threshold and action potential (AP) shape, produced by active vs. passive recharge burst stimulation to gain mechanistic insights that may drive waveform optimization.

Psoriatic Involvement of the Ear

Psoriatic Involvement of the Ear

Tethered Capacitor Charge Mitigation in Electron Beam Experiments

Energetic electron beams have been proposed for tracing magnetic field lines from the magnetosphere down to the ionosphere, in active experiments aimed at diagnosing mechanisms at play in the coupling between magnetosphere and ionosphere. It is recognized however that in the absence of an efficient mitigation technique, this approach would lead to unacceptably large spacecraft charging and positive potential buildup, which would result in environmental hazard for the spacecraft. This problem would be particularly acute in low density regions of the magnetosphere of interest in the study of magnetic field reconnection and substorm dynamics. A solution to this predicament could consist of creating a plasma contactor whereby a gas puff would be ionized, leading to the evacuation of positive charges and collection of cold electrons, thus compensating for the charges lost in the electron beam. A possible alternative is presented here, which consists of attaching a large passive conducting surface to the spacecraft, a “tethered capacitor”, from which negative charges would be drawn to compensate for those lost from the beam. This capacitor would then charge to a large positive potential, leaving the spacecraft and electron gun at a lower, acceptable positive potential. The tethered capacitor could have a relatively small mass; consisting only of a thin conducting surface that would be “inflated” as a result of repulsive electrostatic forces. This charge mitigation concept, as applied to active electron beam experiments, is explored using three dimensional particle-in-cell (PIC) simulations from which scaling laws can be inferred for the spacecraft and tethered capacitor potentials under proposed electron beam operations.

Multi-dimensional flow cytometry analysis reveals increasing changes in the systemic neutrophil compartment during seven consecutive days of endurance exercise.

Endurance exercise is associated with a transient increase in neutrophil counts in the peripheral blood. Here we investigate the impact of intensified endurance exercise on the neutrophil compartment. We hypothesized that intensified endurance exercise leads to mobilization of neutrophil subsets, which are normally absent in the blood. Furthermore, we followed the potential build-up of neutrophil activation and the impact on overnight recovery of the neutrophil compartment during a seven-day cycling tour. The neutrophil compartment was studied in 28 healthy amateur cyclists participating in an eight-day strenuous cycling tour. Blood samples were taken at baseline, after 4 days and after 7 days of cycling. The neutrophil compartment was analyzed in terms of numbers and its phenotype by deep phenotyping of flow cytometry data with the multi-dimensional analysis method FLOOD. Repeated endurance exercise led to a gradual increase in total neutrophil counts over the days leading to a 1.26 fold-increase (95%CI 1.01–1.51 p = 0.0431) in the morning of day 8. Flow cytometric measurements revealed the appearance of 2 additional neutrophil subsets: CD16brightCD62Ldim and CD16dimCD62Lbright. A complex change in neutrophil phenotypes was present characterized by decreased expression of both CD11b and CD62L and marked increased expression of LAIR-1, VLA-4 and CBRM1/5. The changes in expression were found on all neutrophils present in the blood. Strikingly, in strong contrast to our findings during acute inflammation evoked by LPS challenge, these neutrophils did not upregulate classical degranulation markers. In fact, our FLOOD analysis revealed that the exercise induced neutrophil phenotype did not overlap with the neutrophil subsets arising upon acute inflammation. In conclusion, during multiple days of endurance exercise the neutrophil compartment does not regain homeostasis overnight. Thereby our study supports the concept of a build-up of inflammatory cues during repeated endurance exercise training, causing a prolonged change of the systemic neutrophil compartment.

Thermal impact of adhesive-mounted rooftop PV on underlying roof shingles

Adhesive mounting of residential rooftop photovoltaics (PV) is an alternative to traditional rack mounting that reduces installation costs. Adhesive mounting is fast, simple and reduces the need for skilled labor. In our novel design that further reduces the installation costs, a lightweight (glassless and frameless) PV module is directly adhered to a shingled roof using an adhesive tape, creating a <5 mm air gap between the PV back-panel and the roof shingle surface. Although the gap is sufficient for moisture and rainwater transport under the PV panel, potential heat buildup under the module may adversely impact the long-term durability of the shingles. Heat buildup may also increase the heat flux through the roof, resulting in an overall increase in building cooling loads. This study investigates the thermal behavior of the roof under an adhered PV system. Two identical test huts with dark shingle-covered roofs were located in the hot, desert climate of Albuquerque, NM. Adhesively-mounted lightweight PV modules were installed on the south-facing roof of one of the test huts (PV hut), with the other one serving as a reference hut. During the summer season, the asphalt roof shingles under the PV modules experienced a 13 °C reduction in daytime peak temperature compared with the exposed shingles. No evidence of heat buildup under the PV module was observed. It was also found that the temperature of shingles underneath the adhesive was up to 6 °C higher than for shingles underneath the gap space at the daily peak time. Thin but ventilated air gap between the PV back-panel and the roof shingles helped remove the heat, while the adhesive pads (patches) served as thermal bridges between the PV module and the roof. Daily peak heat flow through the attic ceiling was almost 49% lower in the PV hut compared to the reference hut. These results show no evidence of an adverse thermal impact of the adhesive-mounted PV system on the roofing materials, while demonstrating a potential for a notable reduction in space conditioning energy requirements.

A Possible Tectonic Response Between the Qingchuan Faultand the Beichuan‐Yingxiu Fault of the Longmen Shan Fault Zone? Evidence From Geologic Observations by Paleoseismic Trenching and Radiocarbon Dating

AbstractThe Qingchuan fault is located along the eastern margin of the Tibetan Plateau and connects to the Beichuan‐Yingxiu fault of the Longmen Shan fault zone (LMSF), which produced the 2008 MW 7.9 Wenchuan earthquake and 2013 MW6.6 Lushan earthquake. After the two devastating earthquakes, whether the Qingchuan fault could produce a large earthquake or not and its tectonic activity is highly debated. Based on the detailed field investigations and paleoseismic trenching combined with multiple radiocarbon dating, we suggest that the Qingchuan fault might not show intense fault activity (or specific dextral strike‐slip deformation) since the late Quaternary. The deformation evidence revealed in the trench indicates a pattern of tensional deformation in the strata, which is inconsistent with the regional compressional tectonic stress field. Moreover, the timing of these deformation events coincides with that of paleoearthquakes that occurred on the Beichuan‐Yingxiu fault. Therefore, we speculate that the large earthquakes that occurred on the northern segment of the Beichuan‐Yingxiu fault highly likely contribute to the formation of the tensional structures observed along the Qingchuan fault. The uplift of the Minshan Mountain affects the tectonic deformation and seismic activity of the northern segment of the LMSF. However, considering that the LMSF shows forward‐thrust characteristics, the fault activity of the Qingchuan fault was possibly the most affected by the uplifting of the Minshan Mountain. In other words, this specific regional tectonic frame might constrain the buildup of tectonic stress and seismic potential for generating large earthquakes on the Qingchuan fault.

Anisotropic polarization-induced conductance at a ferroelectric-insulator interface.

Coupling between different degrees of freedom, that is, charge, spin, orbital and lattice, is responsible for emergent phenomena in complex oxide heterostrutures1,2. One example is the formation of a two-dimensional electron gas (2DEG) at the polar/non-polar LaAlO3/SrTiO3 (LAO/STO)3-7 interface. This is caused by the polar discontinuity and counteracts the electrostatic potential build-up across the LAO film3. The ferroelectric polarization at a ferroelectric/insulator interface can also give rise to a polar discontinuity8-10. Depending on the polarization orientation, either electrons or holes are transferred to the interface, to form either a 2DEG or two-dimensional hole gas (2DHG)11-13. While recent first-principles modelling predicts the formation of 2DEGs at the ferroelectric/insulator interfaces9,10,12-14, experimental evidence of a ferroelectrically induced interfacial 2DEG remains elusive. Here, we report the emergence of strongly anisotropic polarization-induced conductivity at a ferroelectric/insulator interface, which shows a strong dependence on the polarization orientation. By probing the local conductance and ferroelectric polarization over a cross-section of a BiFeO3-TbScO3 (BFO/TSO) (001) heterostructure, we demonstrate that this interface is conducting along the 109° domain stripes in BFO, whereas it is insulating in the direction perpendicular to these domain stripes. Electron energy-loss spectroscopy and theoretical modelling suggest that the anisotropy of the interfacial conduction is caused by an alternating polarization associated with the ferroelectric domains, producing either electron or hole doping of the BFO/TSO interface.

Countering hybrid warfare as ontological security management: the emerging practices of the EU and NATO

ABSTRACTWhat are the ethical pitfalls of countering hybrid warfare? This article proposes an ontological security-inspired reading of the EU and NATO’s engagement with hybrid threats. It illustrates how hybrid threat management collapses their daily security struggles into ontological security management exercise. This has major consequences for defining the threshold of an Article 5 attack and the related response for NATO, and the maintenance of a particular symbolic order and identity narrative for the EU. The institutionalisation of hybrid threat counteraction emerges as a routinisation strategy to cope with the “known unknowns”. Fostering resilience points at the problematic prospect of compromising the fuzzy distinction between politics and war: the logic of hybrid conflicts presumes that all politics could be reduced to a potential build-up phase for a full-blown confrontation. Efficient hybrid threat management faces the central paradox of militant democracy whereby the very attempt to defend democracy might harm it.

Mark-to-Market Accounting and Systemic Risk in the Financial Sector

One of the most contentious issues raised during the recent crisis has been the potentially exacerbating role played by mark-to-market accounting. Many have proposed the use of historical cost accounting, promoting its ability to avoid the amplification of systemic risk. We caution against focusing on the accounting rule in isolation, and instead emphasize the interaction between accounting and the regulatory framework. First, historical cost accounting, through incentives that arise via interactions with complex capital adequacy regulation, does generate market distortions of its own. Second, while mark-to-market accounting may indeed generate fire sales during a crisis, forward-looking institutions that rationally internalize the probability of fire sales are incentivized to adopt a more prudent investment strategy during normal times which leads to a safer portfolio entering the crisis. Using detailed, position- and transaction-level data from the U.S. insurance industry, we show that (a) market prices do serve as ‘early warning signals’, (b) insurers that employed historical cost accounting engaged in greater degrees of regulatory arbitrage before the crisis and limited loss recognition during the crisis, and (c) insurers facing mark-to-market accounting tend to be more prudent in their portfolio allocations. Our identification relies on the sharp difference in statutory accounting rules between life and P&C companies as well as the heterogeneity in implementation of these rules within each insurance type across U.S. states. Rather than promoting a shift away from market-based information, our results indicate that regulatory simplicity may be preferred to the complexity of risk-weighted capital ratios that gives rise, through interactions with accounting rules, to distorted risk-taking incentives and potential build-up of systemic risk.

Derivation of the threshold condition for the ion temperature gradient mode with an inverted density profile from a simple physics picture

We show that the threshold condition for the toroidal ion temperature gradient (ITG) mode with an inverted density profile can be derived from a simple physics argument. The key in this picture is that the density inversion reduces the ion compression due to the ITG mode and the electron drift motion mitigates the poloidal potential build-up. This condition reproduces the same result that has been reported from a linear gyrokinetic calculation [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. The destabilizing role of trapped electrons in toroidal geometry is easily captured in this picture.

Onset of phase separation in the double perovskite oxide La2MnNiO6

Identification of kinetic and thermodynamic factors that control crystal nucleation and growth represents a central challenge in materials synthesis. Here we report that apparently defect-free growth of ${\mathrm{La}}_{2}{\mathrm{MnNiO}}_{6}$ (LMNO) thin films supported on ${\mathrm{SrTiO}}_{3}$ (STO) proceeds up to 1--5 nm, after which it is disrupted by precipitation of NiO phases. Local geometric phase analysis and ensemble-averaged x-ray reciprocal space mapping show no change in the film strain away from the interface, indicating that mechanisms other than strain relaxation induce the formation of the NiO phases. Ab initio simulations suggest that the electrostatic potential build-up associated with the polarity mismatch at the film-substrate interface promotes the formation of oxygen vacancies with increasing thickness. In turn, oxygen deficiency promotes the formation of Ni-rich regions, which points to the built-in potential as an additional factor that contributes to the NiO precipitation mechanisms. These results suggest that the precipitate-free region could be extended further by either incorporating dopants that suppress the built-in potential or by increasing the oxygen fugacity in order to suppress the formation of oxygen vacancies.

Seismic Hazard in Syria Based on Completeness Analysis and Assessment

An important criterion for conducting an accurate seismic hazard analysis and assessment is the compiling of a representative and completehistorical seismic catalog for the region of interest. This paper describes the procedure to assemble a full earthquake events catalog for Syria from the years 37 AD to 2011 AD. The procedure starts with improving the quality of the compiled full catalog by eliminating manmade events by choosing a cutoff magnitude of 2.5; and by eliminating the potential aftershocks and afforeshcks using an appropriate declustering method. To examine the quality of the resultant seismic catalog (after eliminating artificial, aftershock and afforeshok earthquake) the magnitude of completeness (MC) was calculated and the distribution of MC with time showed an overall good quality of the adopted complete catalog. The adopted complete seismic catalog is then used to generate peak ground acceleration hazard maps for 475, 1000 and 2475 years return periods. The study also concludes that to accommodate for the quiescence of the DSFS and potential undetected buildup and release of seismic energy it is important to introduce 1000 and 2475 years return periods seismic hazard maps especially in the design of important structures.

Molecular simulations of the piezoionic effect.

We present a molecular dynamics study of two polyelectrolyte gels with different degrees of ionization coupled in a slab geometry. Our simulations show that a pressure gradient emerges between the two gels that results in the buildup of a Nernst-Donnan potential. This methodology is reverse to experiments of the piezoionic or mechanoelectric effect, in which an electric potential gradient appears upon application of a pressure gradient to a hydrogel. The Nernst-Donnan potential at the interface is found to scale linearly with temperature with the coefficient of proportionality given by the fraction of concentrations of the uncondensed counterions. We show that the potential difference can also be expressed as a linear function of the lateral pressure, thus providing a molecular interpretation of the piezoionic effect.

Precursor processes of human self-initiated action

A gradual buildup of electrical potential over motor areas precedes self-initiated movements. Recently, such “readiness potentials” (RPs) were attributed to stochastic fluctuations in neural activity. We developed a new experimental paradigm that operationalized self-initiated actions as endogenous ‘skip’ responses while waiting for target stimuli in a perceptual decision task. We compared these to a block of trials where participants could not choose when to skip, but were instead instructed to skip. Frequency and timing of motor action were therefore balanced across blocks, so that conditions differed only in how the timing of skip decisions was generated. We reasoned that across-trial variability of EEG could carry as much information about the source of skip decisions as the mean RP. EEG variability decreased more markedly prior to self-initiated compared to externally-triggered skip actions. This convergence suggests a consistent preparatory process prior to self-initiated action. A leaky stochastic accumulator model could reproduce this convergence given the additional assumption of a systematic decrease in input noise prior to self-initiated actions. Our results may provide a novel neurophysiological perspective on the topical debate regarding whether self-initiated actions arise from a deterministic neurocognitive process, or from neural stochasticity. We suggest that the key precursor of self-initiated action may manifest as a reduction in neural noise.

Evaluating the health risks of potentially toxic elements through wheat consumption in multi-industrial metropolis of Faisalabad, Pakistan.

Potentially toxic elements (PTEs) pollution is the fastest growing concern around the entire globe especially in developing countries. Rapid industrialization and urbanization are the dominant sources of anthropogenic soil-food chain contamination with PTEs. The intent of current study was to investigate the interactive levels of Cu, Fe, Mn, Ni, Pb, and Zn in soil and their accumulation in wheat (Triticum aestivum L.) samples collected from 96 sites including industrial, urban, and peri-urban areas of a leading multi-industrialized center (Faisalabad) of Pakistan. According to results obtained from present study, non-carcinogenic (HQ) and life-time carcinogenic risks (CR) of the PTEs to the local inhabitants were estimated following the risk assessment modals proposed by the US-EPA. With respect to estimated HQ for chronic non-carcinogenic risk of Mn, Ni, and Pb, higher potential hazards were observed as compared to Cu, Fe, and Zn. Meanwhile, the carcinogenic risk of Ni marginally exceeded the limit described by US-EPA for adults. Overall, the health risks of PTEs with the consumption of wheat were lower than the limits described by US-EPA except for Ni. However, continuous consumption of this PTEs contaminated food may result the potential buildup of poisonousness and various disorders in humans. Therefore, long-term monitoring and gastrointestinal bio-accessibility studies are requisite for the safety of humans under such conditions.

Wind characteristics of CzeCOS’s ecosystem station Bílý Kříž

Eddy-covariance is a direct and accurate method to measure exchanges of greenhouse gases and energy between ecosystems and the atmosphere under good turbulent mixing conditions. Calm conditions can affect the accuracy of the eddy-covariance measurements by potential gas buildup below the measurement height. This study characterizes wind patterns and calm periods at Bílý Kříž Ecosystem Research Station, using four-year (2010-2013) wind data measured on an eddy-covariance tower at the site, located in Beskids Mountains, Czech Republic. The site is covered by young, dense Norway spruce forest on a 12.5° slope facing South. The results show that the prevailing wind direction was from S to SW direction (55 % frequency of occurrence), and to a much lesser extent from N, NE and NW but including the strongest winds above 12 m s-1, possibly during gale or storm events. Calm condition (u &lt; 1 m s-1) accounted for 34 % of year time. Summer and Spring were the calmest seasons. Occurrence frequencies of calm conditions for the six-month periods from May to October (plant growing season) were higher than those for the remaining parts of the year (on average 39 % vs 28 % respectively). One should be aware of the calm periods in May-October when processing eddy-covariance data, since it is the time period of most contribution of forest ecosystem as a sink of CO2.

Mutual Information and Parameter Estimation in the Generalized Inverse Gaussian Diffusion Model of Cortical Neurons

We propose a novel model of postsynaptic potential buildup and action potential upswing of cortical neurons using the generalized inverse Gaussian (GIG) diffusion of Barndorff-Nielsen, Blaesild, and Halgreen. A certain subset of GIG diffusions exhibit attraction to a threshold, a phenomenon widely observed in biological neurons. The parameters in this model control the variance, components of the drift, and the height of threshold. These parameters can be estimated from a sample path of the GIG diffusion using a modification of the maximum likelihood estimator from the Euler method approximation. The input intensity of the cortical neuron is also estimated using similar methods. We use Monte Carlo simulations to evaluate the effectiveness of the estimators. Of interest to information theorists and neuroscientists is the mutual information between the input intensity of a cortical neuron and the time of firing of its output spike in response to that input intensity. We determine said mutual information for the GIG diffusion model of the neuron.