Development of space stable thermal control coatings for use on large space vehicles

The evaluation and environmental testing of zinc orthotitanate pigments for use as space stable thermal control coatings on large space vehicles are discussed. Electron paramagnetic resonance spectra of the pigments and their precursor compounds are examined. A continuing study of the spectral intensity of mercury-argon and mercury-xenon sources in reported. Results of long term environmental testing of commercially available, strippable, protective coatings are discussed

Coupling techniques for nonlinear hyperbolic equations. III. The well-balanced approximation of thick interfaces

We continue our analysis of the coupling between nonlinear hyperbolic problems across possibly resonant interfaces. In the first two parts of this series, we introduced a new framework for coupling problems which is based on the so-called thin interface model and uses an augmented formulation and an additional unknown for the interface location; this framework has the advantage of avoiding any explicit modeling of the interface structure. In the present paper, we pursue our investigation of the augmented formulation and we introduce a new coupling framework which is now based on the so-called thick interface model. For scalar nonlinear hyperbolic equations in one space variable, we observe that the Cauchy problem is well-posed. Then, our main achievement in the present paper is the design of a new well-balanced finite volume scheme which is adapted to the thick interface model, together with a proof of its convergence toward the unique entropy solution (for a broad class of nonlinear hyperbolic equations). Due to the presence of a possibly resonant interface, the standard technique based on a total variation estimate does not apply, and DiPerna's uniqueness theorem must be used. Following a method proposed by Coquel and LeFloch, our proof relies on discrete entropy inequalities for the coupling problem and an estimate of the discrete entropy dissipation in the proposed scheme.Comment: 21 page

Beyond 2020: How General Education Archaeology Curricula Should Adapt to the COVID-19 Pandemic

Archaeology often justifies its existence by invoking the trope that we must learn about the past in order to create a better future. The COVID-19 pandemic is itself an event that will enter the historical record. Thus, the universality of this public health crisis is a unique opportunity to assess the relevance of university-level archaeology curricula to our present historical moment. We studied an upper division general education course on the archaeology of complex societies at a public liberal arts college in California. The instrument of data collection was a questionnaire administered at the end of the Fall 2020, Spring 2021, and Spring 2022 semesters. Students read an article about archaeological approaches to pandemics, then reflected on how it connected to course content and to their own experiences during the COVID-19 pandemic. Content analysis of student responses suggests that course themes of complex societies, the environment, archaeological evidence, the future, and social hierarchy resonated most with students on both intellectual and personal levels. We also identified emergent concerns with diseases (COVID-19 and others) and cultural responses to them, employment status, and psychological effects, suggesting that these themes are increasingly relevant to archaeology students during and beyond the COVID-19 pandemic

Atrazine contamination at the watershed scale and environmental factors affecting sampling rates of the polar organic chemical integrative sampler (POCIS)

AbstractPolar organic chemical integrative samplers (POCIS) were used to estimate atrazine contamination at 24 stream/river sites located across a watershed with land use ranging from 6.7 to 97.4% annual crops and surface water nitrate concentrations ranging from 3 to 5404 μg/L. A gradient of atrazine contamination spanning two orders of magnitude was observed over two POCIS deployments of 28 d and was positively correlated with measures of agricultural intensity. The metabolite desisopropyl atrazine was used as a performance reference compound in field calibration studies. Sampling rates were similar between field sites but differed seasonally. Temperature had a significant effect on sampling rates while other environmental variables, including water velocity, appeared to have no effect on sampling rates. A performance reference compound approach showed potential in evaluating spatial and temporal differences in field sampling rates and as a tool for further understanding processes governing uptake of polar compounds by POCIS

Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise

We observe measurement-induced qubit state mixing in a transmon qubit dispersively coupled to a planar readout cavity. Our results indicate that dephasing noise at the qubit-readout detuning frequency is up-converted by readout photons to cause spurious qubit state transitions, thus limiting the nondemolition character of the readout. Furthermore, we use the qubit transition rate as a tool to extract an equivalent flux noise spectral density at f ~ 1 GHz and find agreement with values extrapolated from a $1/f^\alpha$ fit to the measured flux noise spectral density below 1 Hz.Comment: 5 pages, 4 figures. Final journal versio

Status of the left ventricle after arterial switch operation for transposition of the great arteries Hemodynamic and echocardiographic evaluation

AbstractBackground : The potential for improved preservation of systemic ventricular function represents an important reason for the increasing popularity of the arterial switch operation. In support of this expectation, prior studies in patients early after arterial switch operation have found normal ventricular contractility and function. This study was conducted to extend those observations to up to 10 years of follow-up and to directly examine the effects of a coexisting ventricular septal defect or short-term preparatory banding of the pulmonary artery before the arterial switch operation. Methods : Patients operated on from 1983 through 1991 were included. Echocardiographic and catheterization data were collected as part of a prospective evaluation of outcome in all patients who undergo the arterial switch operation at Boston Children's Hospital, with inclusion of data from the most recent catheterization only. Echocardiograms performed at least 6 months after the operation were included, with assessment of both the most recent status as well as serial trends. Whenever possible, echocardiographic evaluation included data necessary to perform analysis of ventricular mechanics including indices of afterload, preload, and contractility. Comparison was made to normal values and between subgroups defined on the basis of an arterial switch operation with or without ventricular septal defect and those who had a rapid two-stage arterial switch operation. Results : Invasive measures of left and right ventricular filling pressures, cardiac index, and pulmonary vascular resistance did not differ among the three groups. Overall, echocardiographic left ventricular end-diastolic dimension, wall thickness, mass, afterload (end-systolic wall stress), function (fractional shortening and rate-corrected velocity of fiber shortening), contractility (stress-velocity and stress-shortening relations), and preload were normal, and none of these variables was different between the groups with and without a ventricular septal defect. Serial evaluation indicated a slight but significant trend toward ventricular dilatation, perhaps related to a relatively high incidence of at least mild aortic regurgitation (30%). In contrast, in the rapid two-stage group the echocardiographic indices of left ventricular function (fractional shortening and velocity of fiber shortening) and contractility (stress-velocity and stress-shortening relations) were found to be mildly but significantly reduced compared with normal subjects and with the other arterial switch operation groups. Over the duration of follow-up encompased by this study, no tendency toward progressive depression of function was seen. Conclusions : As the length of observation after the arterial switch operation continues to increase, left ventricular size, mass, functional status, and contractility continues to be normal, with no evidence of time-related deterioration of function. As previously reported, the rapid two-stage arterial switch operation does represent a higher risk for mild impairment of myocardial mechanics. (J T horac C ardiovasc S urg 1995;109:311-21

Individual Characteristics That Promote or Prevent Psychological Safety and Error Reporting in Healthcare: A Systematic Review.

BACKGROUND: Healthcare errors continue to be a safety issue and an economic burden that causes death, increased length of stays, and emotional trauma to families and the person who commits the error.  Speaking up and error reporting within a safety culture can reduce the incidence of error; however, this is complex and multifaceted. AIM: This systematic review investigates individual characteristics that support or prevent speaking up behaviors when adverse events occur.  This study further explores how organizational interventions designed to promote error reporting correlate to individual characteristics and perceptions of psychological safety.  . METHODS: A systematic review of peer-reviewed articles in healthcare that contain characteristics of an individual that promote or prevent error reporting was conducted. The search yielded 1233 articles published from 2015 to 2021. From this set, 81 full-text articles were assessed for eligibility and ultimately extracted data from 28 articles evaluated for quality using Joanna Briggs Institute critical appraisal tools©. PRINCIPAL FINDINGS: The primary themes for individual character traits, values, and beliefs that influence a person\u27s decision to speak up/report an error include self-confidence and positive perceptions of self, the organization, and leadership. Education, experience and knowledge are sub themes that relate to confidence. The primary individual characteristics that serve as barriers are 1) self-preservation associated with fear and 2) negative perceptions of self, the organization, and leadership. CONCLUSION: The results show that an individual\u27s perception of their environment, whether or not it is psychologically safe, may be impacted by personal perceptions that stem from deep-seated personal values. This exposes a crucial need to explore cultural and diversity aspects of healthcare error reporting and how to individualize interventions to reduce fear and promote error reporting