Linear iterative solvers for implicit ODE methods

The numerical solution of stiff initial value problems, which lead to the problem of solving large systems of mildly nonlinear equations are considered. For many problems derived from engineering and science, a solution is possible only with methods derived from iterative linear equation solvers. A common approach to solving the nonlinear equations is to employ an approximate solution obtained from an explicit method. The error is examined to determine how it is distributed among the stiff and non-stiff components, which bears on the choice of an iterative method. The conclusion is that error is (roughly) uniformly distributed, a fact that suggests the Chebyshev method (and the accompanying Manteuffel adaptive parameter algorithm). This method is described, also commenting on Richardson's method and its advantages for large problems. Richardson's method and the Chebyshev method with the Mantueffel algorithm are applied to the solution of the nonlinear equations by Newton's method

The Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS): model description and application to a temperate deciduous forest canopy

Forest canopies are primary emission sources of biogenic volatile organic compounds (BVOCs) and have the potential to significantly influence the formation and distribution of secondary organic aerosol (SOA) mass. Biogenically-derived SOA formed as a result of emissions from the widespread forests across the globe may affect air quality in populated areas, degrade atmospheric visibility, and affect climate through direct and indirect forcings. In an effort to better understand the formation of SOA mass from forest emissions, a 1-D column model of the multiphase physical and chemical processes occurring within and just above a vegetative canopy is being developed. An initial, gas-phase-only version of this model, the Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS), includes processes accounting for the emission of BVOCs from the canopy, turbulent vertical transport within and above the canopy and throughout the height of the planetary boundary layer (PBL), near-explicit representation of chemical transformations, mixing with the background atmosphere and bi-directional exchange between the atmosphere and canopy and the atmosphere and forest floor. The model formulation of ACCESS is described in detail and results are presented for an initial application of the modeling system to Walker Branch Watershed, an isoprene-emission-dominated forest canopy in the southeastern United States which has been the focal point for previous chemical and micrometeorological studies. Model results of isoprene profiles and fluxes are found to be consistent with previous measurements made at the simulated site and with other measurements made in and above mixed deciduous forests in the southeastern United States. Sensitivity experiments are presented which explore how canopy concentrations and fluxes of gas-phase precursors of SOA are affected by background anthropogenic nitrogen oxides (NO<sub>x</sub>). Results from these experiments suggest that the level of ambient NO<sub>x</sub> influences the pathways by which SOA is formed by affecting the relative magnitudes and fluxes of isoprene oxidation products emitted from the canopy. Future versions of the ACCESS model are planned to be multiphase, including gas- and aerosol-phase chemical and physical processes, to more fully explore these preliminary results

Bridging the Gap: Three Strategies to Optimize Professional Relationships with Generation Y and Z

Millennials (Generation Y) and the Generation Z population comprise the majority of occupational therapy student cohorts and new graduates entering the workforce. While fieldwork education has historically prepared students for generalist, entry-level practice, there is still a gap between what students versus employers feel are career-ready skills and qualities to be successful in the workforce. This manuscript presents evidenced-based strategies for educators, occupational therapists, and managers to enhance the preparation and professional development of occupational therapy students and new graduates. Use of coaching philosophies, emphasizing practice-ready skills, and a growth mindset are methods to target the strengths of Generations Y and Z members and address areas of growth as they prepare to enter the workforce. Emphasizing human relationships over task completion or skill mastery helps uphold the values of millennials and the Generation Z population that they can make an impact in the workplace. Modeling practice-ready skills, explicit discussion of “soft” skills, and use of guided discovery supports these generations’ understanding of basic workplace etiquette and culture. Using a growth mindset philosophy can help foster initiative and self-awareness, which are potential areas of growth for these generations. These strategies can then promote healthy, productive collaboration in the workplace and, ultimately, enhance the client-provider relationship

Atmospheric circulation patterns, cloud-to-ground lightning, and locally intense convective rainfall associated with debris flow initiation in the Dolomite Alps of northeastern Italy

The Dolomite Alps of northeastern Italy experience debris flows with great frequency during the summer months. An ample supply of unconsolidated material on steep slopes and a summer season climate regime characterized by recurrent thunderstorms combine to produce an abundance of these destructive hydro-geologic events. In the past, debris flow events have been studied primarily in the context of their geologic and geomorphic characteristics. The atmospheric contribution to these mass-wasting events has been limited to recording rainfall and developing intensity thresholds for debris mobilization. This study aims to expand the examination of atmospheric processes that preceded both locally intense convective rainfall (LICR) and debris flows in the Dolomite region. 500 hPa pressure level plots of geopotential heights were constructed for a period of 3 days prior to debris flow events to gain insight into the synoptic-scale processes which provide an environment conducive to LICR in the Dolomites. Cloud-to-ground (CG) lightning flash data recorded at the meso-scale were incorporated to assess the convective environment proximal to debris flow source regions. Twelve events were analyzed and from this analysis three common synoptic-scale circulation patterns were identified. Evaluation of CG flashes at smaller spatial and temporal scales illustrated that convective processes vary in their production of CF flashes (total number) and the spatial distribution of flashes can also be quite different between events over longer periods. During the 60 min interval immediately preceding debris flow a majority of cases exhibited spatial and temporal colocation of LICR and CG flashes. Also a number of CG flash parameters were found to be significantly correlated to rainfall intensity prior to debris flow initiation

Protective Coating Program Final Report

This program consists of two primary segments: 1) installing an environmental monitoring station at the Toyota marshalling yard at Georgetown, Kentucky, and 2) conducting laboratory and field tests of paint and wax-coated painted specimens to assess the protection against acid rain damage afforded by a protective transient coating

Emotional expression during attention-deficit/hyperactivity disorders treatment: initial assessment of treatment effects.

OBJECTIVE: The purpose of this research was to provide an initial examination of the effects of atomoxetine and stimulants on emotional expression using a newly developed scale for assessing emotional expression in children with attention-deficit/hyperactivity disorder (ADHD). METHOD: The parent-rated Expression and Emotion Scale for Children (EESC) was collected during two studies. During a cross-sectional validation study, the EESC was completed to assess the child\u27s current treatment and retrospectively for previous medication. In a randomized, placebo-controlled trial of atomoxetine, the EESC was collected at baseline and endpoint. RESULTS: In the validation study, no statistically significant differences in EESC scores were found between groups taking atomoxetine (n = 74) and stimulants (n = 105). Patients who switched from a stimulant to atomoxetine (n = 40) had greater improvement in emotional expression than those switched to another stimulant (n = 21) (p = 0.008). In the clinical trial, no difference in rates of worsening of emotional expression were observed (atomoxetine 8.8%, placebo 12.3%; p = 0.440). CONCLUSION: No treatment differences in emotional expression were observed based on current medications. However, stimulant patients needing to switch medications may have greater improvements in emotional expression by switching to atomoxetine

Measurement of Unpolarized and Polarized Cross Sections for Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory with CLAS

This paper reports the measurement of polarized and unpolarized cross sections for the ep→e′p′γ reaction, which is composed of deeply virtual Compton scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 \u3c xB \u3c 0.58, 1.0 \u3c Q2 \u3c4.8 GeV2 and 0.09\u3c−t \u3c2.00 GeV2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models are approximately compatible with the experimental results over a large portion of the kinematic range of the data