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Experiments were performed within Sandia National Labs’ Multiphase Shock Tube to measure and quantify the shock-induced dispersal of a shock/dense particle curtain interaction. Following interaction with a planar travelling shock wave, schlieren imaging at 75 kHz was used to track the upstream and downstream edges of the curtain. Data were obtained for two particle diameter ranges (
) across Mach numbers ranging from 1.24 to 2.02. Using these data, along with data compiled from the literature, the dispersion of a dense curtain was studied for multiple Mach numbers (1.2–2.6), particle sizes (
) and volume fractions (9–32 %). Data were non-dimensionalized according to two different scaling methods found within the literature, with time scales defined based on either particle propagation time or pressure ratio across a reflected shock. The data show that spreading of the particle curtain is a function of the volume fraction, with the effectiveness of each time scale based on the proximity of a given curtain’s volume fraction to the dilute mixture regime. It is seen that volume fraction corrections applied to a traditional particle propagation time scale result in the best collapse of the data between the two time scales tested here. In addition, a constant-thickness regime has been identified, which has not been noted within previous literature.
The efficient and effective movement of research into practice is acknowledged as crucial to improving population health and assuring return on investment in healthcare research. The National Center for Advancing Translational Science which sponsors Clinical and Translational Science Awards (CTSA) recognizes that dissemination and implementation (D&I) sciences have matured over the last 15 years and are central to its goals to shift academic health institutions to better align with this reality. In 2016, the CTSA Collaboration and Engagement Domain Task Force chartered a D&I Science Workgroup to explore the role of D&I sciences across the translational research spectrum. This special communication discusses the conceptual distinctions and purposes of dissemination, implementation, and translational sciences. We propose an integrated framework and provide real-world examples for articulating the role of D&I sciences within and across all of the translational research spectrum. The framework’s major proposition is that it situates D&I sciences as targeted “sub-sciences” of translational science to be used by CTSAs, and others, to identify and investigate coherent strategies for more routinely and proactively accelerating research translation. The framework highlights the importance of D&I thought leaders in extending D&I principles to all research stages.
Proximal environments could facilitate smoking cessation among low-income smokers by making cessation appealing to strive for and tenable.
We sought to examine how home smoking rules and proximal environmental factors such as other household members' and peers' smoking behaviors and attitudes related to low-income smokers' past quit attempts, readiness, and self-efficacy to quit.
This analysis used data from Offering Proactive Treatment Intervention (OPT-IN) (randomized control trial of proactive tobacco cessation outreach) baseline survey, which was completed by 2,406 participants in 2011/12. We tested the associations between predictors (home smoking rules and proximal environmental factors) and outcomes (past-year quit attempts, readiness to quit, and quitting self-efficacy).
Smokers who lived in homes with more restrictive household smoking rules, and/or reported having ‘important others’ who would be supportive of their quitting, were more likely to report having made a quit attempt in the past year, had greater readiness to quit, and greater self-efficacy related to quitting.
Adjustments to proximal environments, including strengthening household smoking rules, might encourage cessation even if other household members are smokers.
We propose a cluster-based control strategy for feedback control of post-stall separated flows over an airfoil. The present approach partitions the flow trajectories (force measurements) into clusters, which correspond to characteristic coarse-grained phases in a low-dimensional feature space. A feedback control law (using blowing/suction actuation) is then sought for each cluster state through iterative evaluation and downhill simplex search to minimize power consumption in aerodynamic flight. The optimized control laws re-route the flow trajectories to the aerodynamically favourable regions in the feature space in a model-free manner. Utilizing a limited number of sensor measurements for both clustering and optimization, these feedback laws were determined in only
iterations. The objective of the present work is not necessarily to suppress flow separation but to minimize the desired cost function to achieve enhanced aerodynamic performance. The present approach is applied to the control of two- and three-dimensional separated flows over a NACA 0012 airfoil in large-eddy simulations at an angle of attack of
, Reynolds number
and free-stream Mach number
. The optimized control laws avoid the intermittent occurrence of long-period shedding associated with high-drag clusters, thus lowering the mean drag. The present work aims to address some of the challenges associated with feedback control design for turbulent separated flows at moderate Reynolds number.
What is the function of babbling in language learning? We examined the structure of parental speech as a function of contingency on infants’ non-cry prelinguistic vocalizations. We analyzed several acoustic and linguistic measures of caregivers’ speech. Contingent speech was less lexically diverse and shorter in utterance length than non-contingent speech. We also found that the lexical diversity of contingent parental speech only predicted infant vocal maturity. These findings illustrate a new form of influence infants have over their ambient language in everyday learning environments. By vocalizing, infants catalyze the production of simplified, more easily learnable language from caregivers.
Microstructural analysis and bulk dielectric property analysis (real and imaginary permittivity at 95 GHz) were performed at temperatures ranging from 25 to 550 °C for ceramic composites comprising a hot-pressed aluminum nitride matrix (containing yttria and trace carbon as sintering additives) with molybdenum powder as a millimeter-wave radiation-absorbing additive. Loading percentages in the range of 0.25 vol% to 4.0 vol% Mo were characterized. For the temperature regime evaluated, the temperature-related changes in real and imaginary components of permittivity were found to be relatively modest compared with those driven by Mo loading. Energy-dispersive X-ray spectroscopic analysis of Mo grains and surrounding regions showed the presence of a mixed-phase layer, containing Mo2C, at the AlN–Mo interface. The Mo2C-containing mixed-phase layer, typically a few micrometers thick, surrounded the Mo grains. Further characterization of this mixed-phase layer is required to determine its contribution to the dielectric properties of the composite.
The topology and unsteady behaviour of ventilated and natural cavity flows over a two-dimensional (2-D) wall-mounted fence are investigated for fixed length cavities with varying free-stream velocity using high-speed and still imaging, X-ray densitometry and dynamic surface pressure measurement in two experimental facilities. Cavities in both ventilated and natural flows were found to have a re-entrant jet closure, but not to exhibit large-scale oscillations, yet the irregular small-scale shedding at the cavity closure. Small-scale cavity break-up was associated with a high-frequency broadband peak in the wall pressure spectra, found to be governed by the overlying turbulent boundary layer characteristics, similar to observations from single-phase flow over a forward-facing step. A low-frequency peak reflecting the oscillations in size of the re-entrant jet region, analogous to ‘flapping’ motion in single-phase flow, was found to be modulated by gravity effects (i.e. a Froude number dependence). Likewise, a significant change in cavity behaviour was observed as the flow underwent transition analogous to the transition from sub- to super-critical regime in open-channel flow. Differences in wake topology were examined using shadowgraphy and proper orthogonal decomposition, from which it was found that the size and number of shed structures increased with an increase in free-stream velocity for the ventilated case, while remaining nominally constant in naturally cavitating flow due to condensation of vaporous structures.
Clinical Enterobacteriacae isolates with a colistin minimum inhibitory concentration (MIC) ≥4 mg/L from a United States hospital were screened for the mcr-1 gene using real-time polymerase chain reaction (RT-PCR) and confirmed by whole-genome sequencing. Four colistin-resistant Escherichia coli isolates contained mcr-1. Two isolates belonged to the same sequence type (ST-632). All subjects had prior international travel and antimicrobial exposure.
Angiostrongylus cantonensis is a pathogenic nematode and the cause of neuroangiostrongyliasis, an eosinophilic meningitis more commonly known as rat lungworm disease. Transmission is thought to be primarily due to ingestion of infective third stage larvae (L3) in gastropods, on produce, or in contaminated water. The gold standard to determine the effects of physical and chemical treatments on the infectivity of A. cantonensis L3 larvae is to infect rodents with treated L3 larvae and monitor for infection, but animal studies are laborious and expensive and also raise ethical concerns. This study demonstrates propidium iodide (PI) to be a reliable marker of parasite death and loss of infective potential without adversely affecting the development and future reproduction of live A. cantonensis larvae. PI staining allows evaluation of the efficacy of test substances in vitro, an improvement upon the use of lack of motility as an indicator of death. Some potential applications of this assay include determining the effectiveness of various anthelmintics, vegetable washes, electromagnetic radiation and other treatments intended to kill larvae in the prevention and treatment of neuroangiostrongyliasis.
We used multivariable analyses to assess whether meeting core elements was associated with antibiotic utilization. Compliance with 7 elements versus not doing so was associated with higher use of broad-spectrum agents for community-acquired infections [days of therapy per 1,000 patient days: 155 (39) vs 133 (29), P = .02] and anti-methicillin-resistant S. aureus agents [days of therapy per 1,000 patient days: 145 (37) vs 124 (30), P = .03].
The Strengths and Difficulties Questionnaire (SDQ) has been used in many epidemiological studies to assess adolescent mental health problems, but cross-country comparisons of the self-report SDQ are scarce and so far failed to find a good-fitting, common, invariant measurement model across countries. The present study aims to evaluate and establish a version of the self-report SDQ that allows for a valid cross-country comparison of adolescent self-reported mental health problems.
Using the Health Behaviour in School-aged Children study, the measurement model and measurement invariance of the 20 items of the self-report SDQ measuring adolescent mental health problems were evaluated. Nationally representative samples of 11-, 13- and 15-year old adolescents (n = 33 233) from seven countries of different regions in Europe (Bulgaria, Germany, Greece, the Netherlands, Poland, Romania, Slovenia) were used.
In order to establish a good-fitting and common measurement model, the five reverse worded items of the self-report SDQ had to be removed. Using this revised version of the self-report SDQ, the SDQ-R, partial measurement invariance was established, indicating that latent factor means assessing conduct problems, emotional symptoms, peer relationships problems and hyperactivity-inattention problems could be validly compared across the countries in this study. Results showed that adolescents in Greece scored relatively low on almost all problem subscales, whereas adolescents in Poland scored relatively high on almost all problem subscales. Adolescents in the Netherlands reported the most divergent profile of mental health problems with the lowest levels of conduct problems, low levels of emotional symptoms and peer relationship problems, but the highest levels of hyperactivity-inattention problems.
With six factor loadings being non-invariant, partial measurement invariance was established, indicating that the 15-item SDQ-R could be used in our cross-country comparison of adolescent mental health problems. To move the field of internationally comparative research on adolescent mental health forward, studies should test the applicability of the SDQ-R in other countries in- and outside Europe, continue to develop the SDQ-R as a cross-country invariant measure of adolescent mental health, and examine explanations for the found country differences in adolescent mental health problems.
We assessed the impact of an embedded electronic medical record decision-support matrix (Cerner software system) for the reduction of hospital-onset Clostridioides difficile. A critical review of 3,124 patients highlighted excessive testing frequency in an academic medical center and demonstrated the impact of decision support following a testing fidelity algorithm.
Content analysis is the process of turning text into data, with either automated or manual techniques, and it provides a feasible and attractive option for undergraduate students to develop and utilize original data. This article presents a cohesive framework for teaching computerized content analysis in undergraduate political science courses. The article discusses examples of how we have taught the techniques in our own classrooms and provides a framework for a content-analysis research assignment. We describe coding, sources of text data available to students, software recommendations appropriate for students, and write-up issues. In the process, we also discuss various learning opportunities that arise from both the strengths and weaknesses of computerized content analysis as a methodological strategy.
In order to begin to evaluate and model the suitability of high temperature ceramic composites, such as AlN:Mo, as susceptor materials for power beaming applications, the electromagnetic, thermal, and mechanical properties of the material must be known at elevated temperatures. Work reported here focuses on the development of thermal property datasets for AlN:Mo composites ranging from 0.25% to 4.0% Mo by volume. To calculate thermal conductivity of the AlN:Mo composite series, specific heat capacity, thermal diffusivity, and density data were acquired. The calculated specific heat capacity, Cp, of the set of AlN:Mo composites was, on average, found to be approximately 803 J/kgK at 100 °C and to increase to approximately 1133 J/kgK at 1000 °C, with all values to be within +/- 32 J/kgK of the average at a given temperature. These calculated specific heat capacity values matched values derived from DSC measurements to within the expected error of the measurements. Measured thermal diffusivity, α, of the set of AlN:Mo composites was, on average, found to be approximately 3.93 x 10-1 cm2/s at 100 °C and to increase to approximately 9.80 x 10-2 cm2/s at 1000 °C, with all values within +/- 1.84 x 10-2 cm2/s of the average at a given temperature. Thermal conductivity, k, for the set of AlN:Mo composites was found to be approximately 108 W/mK at 100 °C and to decrease to approximately 38 W/mK at 1000 °C, with all values within +/- 5.3 W/mK of the average at a given temperature. Data trends show that increasing Mo content correlates to lower values of of Cp, α, and k at a given temperature.
We have studied a series of laminated thin films by x-ray diffraction to correlate their structural and magnetic properties. Previous works have shown that the signal-to-noise characteristics of laminated magnetic films with non-magnetic interlayers can exceed that of single layer magnetic films. In the case where the magnetic layer is known to have low signal-to-noise performance, the signal has been observed to increase as the number of layers whereas the noise increases as the square root of the number of layers. This yields a net improvement of the signal-to-noise ratio, making the overall film more attractive as a magnetic recording medium. In this paper, we investigate films which are laminated layers of magnetic CoPtCr and non-magnetic Cr. The films were deposited with sputtering parameters that generally give low noise characteristics in single layer films. Up to four layers of CoPtCr films were made with Cr spacer layers of 2 nm. We observe some improvement in signal-to-noise characteristics and reduction in coercivity. X-ray diffraction analysis shows that the crystallographic c-axis, which corresponds to the magnetic easy axis, becomes more preferentially oriented perpendicular to the film plane with each additional layer. This change in preferred orientation is consistent with the reduced in-plane coercivity of the film. In the double CoPtCr layer with one Cr spacer layer experiment, we see that as the Cr spacer layer is increased from 0.5 to 8 nm, the c-axis of the CoPtCr again becomes more preferentially oriented out of the film plane, resulting in decreased in-plane coercivity. The media signal-to-noise improves once the Cr spacer layer is beyond 2 nm, consistent with previous observations.
Spray drying is shown to be an effective and rapid method for preparing samples for quantitative analysis by x-ray powder diffraction. Previously intractable problems like the simultaneous analysis of multiple phases in orientation prone systems can be carried out. Using this method, and a computer controlled diffractometer, five and six phase analyses of Devonian shales can be accomplished in approximately forty minutes. A rapid and convenient method for using the absorption diffraction technique for x-ray quantitative analysis is described.