The role of plasma wave turbulence in the formation of shock waves in collisionless plasmas

A data set containing measurements for approximately 100 shock crossings was compiled, and plasma wave profiles were plotted in conjunction with magnetic field data. Three emissions analyzed include upstream electron plasma oscillations, ion acoustic noise, and low frequency electromagnetic noise. The data demonstrate that the observed waves are consistent with generation by the kinetic cross-field streaming instability. Reanalysis of shock overshoots prompted by the presence of plasma feet upstream of nominally subcritical shocks leads to the conclusion that no firm evidence exists for a sharp subcritical supercritical transition. Electron plasma oscillations persist up to the ramps of subcritical shocks and begin decaying at the front edge of the feet of supercritical shocks. Their intensity is anticorrelated with the amplitude of the foot ion acoustic noise. Wave measurements support the predicted predominance of lower hybrid-like modes over ion acoustic noise in the production of resistive (plasma) heating. Evidence for variable shock normal angles is seen upstream from nominally quasiparallel shocks. The first cases of very strong electron heating observed at the terrestrial bow shock were discovered

Space Station Freedom solar array panels plasma interaction test facility

The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements

Patient Ventilator Dyssynchrony: Types, Frequency and Patterns in Critically Ill Adults

Patient ventilator dyssynchrony (PVD) occurs frequently, but little is known about the types, frequency and patterns of PVD for longer than 30 minutes. Deeper levels of sedation are associated with PVD. Evaluation of ventilator graphics and the ability to identify PVD should assist clinicians to optimize patient ventilator interactions and promote earlier interventions. The purpose of this study was to identify the different types, frequency and patterns of PVD in critically ill adults and determine the effect of sedation level on PVD. Thirty medical and surgical ICU adult patients were enrolled; 27 were used for analysis. Pressure/time and flow/ time waveform data were collected using the Noninvasive Cardiac Output monitor for up to 90 minutes per subject. Blinded waveform analysis was performed. Sedation level was measured every 20 minutes. A Dyssynchrony Index (DI) and PVD Type Indices were used to describe PVD frequency. Lag analysis was used to detect associated patterns of PVD. PVD occurred during all phases of ventilated breaths and during each of the ventilatory modes used. Heretofore undocumented dyssynchrony in the form of patient gasp PVD, active triggers and combined PVDs were found. The most common type of PVD was Ineffective Trigger (63%), followed by Premature Termination-Flow (17%), Premature Termination (9%), Multiple Trigger (1%), Flow (0.87%) and Delayed Termination (0.09%). The overall frequency of dyssynchronous breaths in the sample was 23% of total breaths analyzed, however 93% of subjects experienced at least one incident of PVD. The overall median DI (Interquartile Range [IQR]) was 4% (1% - 9%) with Ineffective Trigger Index having the highest median index (1.78%). The high DI group (6 subjects, 22%) had a DI (IQR) of 61% (42% - 85%). Seventy seven percent of subjects experienced multiple types of PVD. Premature Termination was followed by Multiple Triggers starting at 3 seconds, but Delayed Termination was followed by Ineffective Triggers, starting at 30 seconds. Clinicians need to recognize PVD, since this is a critical step in evaluating patient ventilator interaction and providing subsequent intervention. PVD interpretation is complex requiring clinicians to clearly understand the operational function of ventilator modes and waveform alterations that occur

Excitatory and inhibitory projections in parallel pathways from the inferior colliculus to the auditory thalamus

Individual subdivisions of the medial geniculate body (MG) receive a majority of their ascending inputs from 1 or 2 subdivisions of the inferior colliculus (IC). This establishes parallel pathways that provide a model for understanding auditory projections from the IC through the MG and on to auditory cortex. A striking discovery about the tectothalamic circuit was identification of a substantial GABAergic component. Whether GABAergic projections match the parallel pathway organization has not been examined. We asked whether the parallel pathway concept is reflected in guinea pig tectothalamic pathways and to what degree GABAergic cells contribute to each pathway. We deposited retrograde tracers into individual MG subdivisions (ventral, MGv; medial, MGm; dorsal, MGd; suprageniculate, MGsg) to label tectothalamic cells and used immunochemistry to identify GABAergic cells. The MGv receives most of its IC input (~75%) from the IC central nucleus (ICc); MGd and MGsg receive most of their input (~70%) from IC dorsal cortex (ICd); and MGm receives substantial input from both ICc (~40%) and IC lateral cortex (~40%). Each MG subdivision receives additional input (up to 32%) from non-dominant IC subdivisions, suggesting cross-talk between the pathways. The proportion of GABAergic cells in each pathway depended on the MG subdivision. GABAergic cells formed ~20% of IC inputs to MGv or MGm, ~11% of inputs to MGd, and 4% of inputs to MGsg. Thus, non-GABAergic (i.e., glutamatergic) cells are most numerous in each pathway with GABAergic cells contributing to different extents. Despite smaller numbers of GABAergic cells, their distributions across IC subdivisions mimicked the parallel pathways. Projections outside the dominant pathways suggest opportunities for excitatory and inhibitory crosstalk. The results demonstrate parallel tectothalamic pathways in guinea pigs and suggest numerous opportunities for excitatory and inhibitory interactions within and between pathways

Nursing faculty\u27s competency to teach patient safety to their students

Does your faculty really have the knowledge and competency to teach patient safety to your students? You will learn about one College of Nursing\u27s identified need for more patient safety faculty competency and the developed action plan designed to improve their competency

DEPLOYED ELECTRONIC MEDICAL RECORD POLICY COMPLIANCE: AN INTRA-DEPARTMENT PRINCIPAL-AGENT PERSPECTIVE

To understand problems related to a policy of implementing a lifelong longitudinal electronic health record (EHR) more fully, this dissertation examines compliance with changes in policy over time. We analyze drivers of compliance with a required electronic medical record (EMR) by hospital clinicians completing the records for deployed service members. This study examines compliance as an outcome of principal-agent (PA) relationships, with the EMR modeled as the measure of success between one level of bureaucratic principal (i.e. medical command) with control over the necessary mechanisms in order to ensure compliance of agents (i.e., medical professionals). Policy compliance is operationalized in three ways: 1) the total number of inpatient EMRs completed; 2) the date on which new records are started; 3) the average number of days to close an inpatient EMR. For each of these dimensions, \u27EMR\u27 refers to what clinicians categorize as treatment for a disease non-battle injury or battle injury. The first independent variable concept for this study is change in the level of information asymmetry between principal and agent, operationalized as the time a superordinate medical command (MEDCOM) is directly in control over hospitals. The second concept is the alignment of goals in order to reduce goal conflict. This is operationalized as a technology upgrade allowing hospital EMR to be used for both implementing the larger EHR as well as in providing real-time clinical notes necessary for the care of patients being evacuated to the next level of medical care. Finally, the concept of principal control mechanisms are operationalized in this study as the introduction of increased monitoring policy and sanctions at the clinician level during hospital transition periods. We use quantitative data in the form of completed electronic medical records and utilize a quasi-experimental research design. The specific design chosen for the study is the interrupted time-series. The population for this study is all United States military service members seen as inpatients in deployed military hospitals directly supporting Operation Iraqi Freedom. The study period is 105 weeks. Overall, this research meets the objectives outlined in Chapter 1 (Introduction). The study examined two important questions regarding clinician compliance with completing EMRs for deployed service members. First, this study addressed if there was a change in policy compliance over time. By conducting an analysis of policy interventions, we established changes in policy compliance. Compliance was defined as the fluctuation in inpatient records started, records completed, and changes in the average time to complete records. Secondly, this study examined what factors influenced the performance of hospital clinicians and how significant these drivers\u27 impact was on record completion. The analysis consisted of graphing the changes over time and examining changes that were most likely due to policy interventions. We further analyzed the changes over time utilizing ANOVA and least squares regression. The results supported many of the hypotheses. Technology upgrades not only led to greater completion rates but also reduced the amount of variation in records completed week to week. The introduction of the monitoring policy also increased both record completions and records started. Finally, sanctioning showed the greatest impact on completing records. This research is important for four reasons. First, this study provides a method to analyze policy implementation at different levels within one federal department. Second, this research enhances the body of knowledge in the inter-disciplinary evaluation of policy implementation. Third, this dissertation examines the role of specific control mechanisms, namely monitoring and sanction, not previously reported in the EHR implementation literature. Finally, this study provides real-world implications for implementing EHR policies in deployed environments. This study determines that the time a MEDCOM is in charge, technology upgrades, monitoring, and sanctions do have an effect on policy compliance but are reliant on the measurement of compliance. As an example, technology upgrades significantly increase the number of EMR completed at hospitals, but they are not statistically significant in increasing or decreasing the number of new encounters started at the hospital. In addition, patient categories influence the significance between the independent and dependent variables

Dependence of CMI Growth Rates on Electron Velocity Distributions and Perturbation by Solitary Waves

We calculate growth rates and corresponding gains for RX and LO mode radiation associated with the cyclotron maser instability for parameterized horseshoe electron velocity distributions. The velocity distribution function was modeled to closely fit the electron distribution functions observed in the auroral cavity. We systematically varied the model parameters as well as the propagation direction to study the dependence of growth rates on model parameters. The growth rate depends strongly on loss cone opening angle, which must be less than $90^{o}$ for significant CMI growth. The growth rate is sharply peaked for perpendicular radiation ($k_{\parallel} = 0$), with a full-width at half-maximum $1.7^{o}$, in good agreement with observed k-vector orientations and numerical simulations. The fractional bandwidth varied between 10$^{-4}$ and 10$^{-2}$, depending most strongly on propagation direction. This range encompasses nearly all observed fractional AKR burst bandwidths. We find excellent agreement between the computed RX mode emergent intensities and observed AKR intensities assuming convective growth length $L_c\approx$20-40 km and group speed 0.15$c$. The only computed LO mode growth rates compatible observed LO mode radiation levels occurred for number densities more than 100 times the average energetic electron densities measured in auroral cavities. This implies that LO mode radiation is not produced directly by the CMI mechanism but more likely results from mode conversion of RX mode radiation. We find that perturbation of the model velocity distribution by large ion solitary waves (ion holes) can enhance the growth rate by a factor of 2-4. This will result in a gain enhancement more than 40 dB depending on the convective growth length within the structure. Similar enhancements may be caused by EMIC waves.Comment: 21 pages, 11 figures. J. Geophys. Res. 2007 (accepted