Search

Microbial diversity in the cystic fibrosis (CF) lung decreases over decades as pathogenic bacteria such as Pseudomonas aeruginosa take over. The dynamics of the CF microbiome and metabolome over shorter time frames, however, remain poorly studied. Here, we analyze paired microbiome and metabolome data from 594 sputum samples collected over 401 days from six adult CF subjects (subject mean = 179 days) through periods of clinical stability and 11 CF pulmonary exacerbations (CFPE). While microbiome profiles were personalized (permutational multivariate analysis of variance [PERMANOVA] r 2 = 0.79, P

Using data from the 2021 Iowa Narrow Cost Analysis of child care, the current study examines business practices of family home child care providers. Family home child care providers make up a sizeable portion of the available child care in Iowa; however, their sustainability is threatened by providers making a low income and lacking access to benefits. The current study describes the enrollment of family home child care, cost drivers of providing care, and participation in business practices such as paying oneself a salary, providing for one's health insurance, accepting state child care subsidy, and participating in the state quality rating system (QRS), as well as relationships among these business practices. Chi-square analyses indicate that providers who accept child care assistance (CCA) are more likely to contribute to their health insurance and provide themselves with paid time off; however, their participation rates in QRS are similar to those who do not accept CCA. Directions for future research and potential points of intervention to support family home childcare (FHCC) providers as small business owners are discussed. [ABSTRACT FROM AUTHOR]

The two-dimensional particle image velocimetry (PIV) data are inevitably contaminated by noise due to various imperfections in instrumentation or algorithm, based on which the well-established vortex identification methods often yield noise or incomplete vortex structure with a jagged boundary. To make up this deficiency, a novel method was proposed in this paper and the efficiency of the new method was demonstrated by its applications in extracting the two-dimensional spanwise vortex structures from 2D PIV data in open-channel flows. The new method takes up a single vortex structure by combining model matching and vorticity filtering, and successfully locates the vortex core and draws a streamlined vortex boundary. The new method shows promise as being more effective than commonly used schemes in open-channel flow applications.

The globus pallidus is a major output station for the basal ganglia, a subcortical region of the brain that is heavilyimplicated in action selection and decision making. A subpopulation of neurons in the internal segment (GPi) projects tothe laternal habenula (LHb), often associated with the limbic system and known to encode for negative motivational value.Dysfunction in these structures have been implicated in neurological diseases, such as depression and schizophrenia,which are ultimately disruptions in the ability to evaluate environmental cues and regulate motor output. In order togain more information about the neurons which encode for this behavior, we conducted extracellular recordings whilethe mice are carrying out a set of reward learning tasks and analyzed the collected spike trains. We detail here themethods of information extraction from the neuronal populations that we have classified. We also present preliminaryresults of their activity profile for various outcomes as well as for reward history and prediction error. With collection ofinformation from a larger set of cells, we might be able to more definitively gain an understanding of the methods bywhich these neurons encode motivation, action selection and outcome evaluation.

Effective management of reservoir sedimentation necessitates the characterization of flood events, especially in relation to the propagation of the flow peak (Qpeak) and the suspended sediment concentration peak (SSCpeak). This study, based on a one‐dimensional river network hydro‐sediment model together with field data, presents an exploration of the flood events in the Three Gorges Reservoir (TGR) with focus on the propagating characteristics of Qpeak and SSCpeak. The findings reveal that the main flood season (from July to September) contributed over 80% of the annual sediment load into the TGR, with the mainstream Yangtze and its tributary, the Jialing River, being the primary sediment sources. After the impoundment of the TGR, the propagation time of Qpeak decreases with the raise of the water level in front of dam (WLdam). The increases in Qpeak discharge extends the range of river reach dominated by kinematic wave, resulting in an increase trend in Qpeak propagation time. The propagating speed of SSCpeak is closely related to the ratio of sediment concentration to flow discharge and WLdam. Finally, the propagating durations of Qpeak and SSCpeak in the TGR are compared, and empirical formulas are proposed for quantifying their difference. [ABSTRACT FROM AUTHOR]

Direct numerical simulations at two friction Reynolds numbers (550 and 1000) have been performed to explore the statistical behaviors of wall-attached motions (WAMs) in open- and closed-channel flows (OCFs and CCFs). To fully capture the largest energetic WAMs, superlarge domain sizes are employed (24–48 π h along streamwise direction with h being the height of OCFs). Based on the analysis of linear coherence spectrum, both geometric and kinematic characteristics of WAMs are investigated. Results revealed that obvious peaks could be found in spanwise coherence spectra of u (streamwise velocity) and w (spanwise velocity) at a wavelength close to 2h. Both the coherence and energy spectra density value of OCFs are greater than those of CCFs at large wavelengths, indicating that OCFs are more wall-attached. Within y/h = 0.2–0.7, the diagnosed streamwise and spanwise wavelengths of WAMs increase roughly linearly with increasing vertical position y. In the upper region (y / h > 0.7), the diagnosed wavelengths in OCFs are smaller than those in CCFs. In addition, the inclination angle of u fluctuates around 14° within y / h = 0.4–0.6, and angles of CCFs are slightly larger than those in OCFs when y / h > 0.6. Regarding kinematic behavior, contribution fractions of WAMs to total turbulent intensity in OCFs are always larger than those in CCFs. Additionally, the wall-attached behaviors of u were found to be more sensitive to Reynolds number than w. [ABSTRACT FROM AUTHOR]

A new image feature tracking velocimetry is presented and tested on airborne video data available from a previous study at Murg Creek (Canton Thurgau, Switzerland). Here, the seeded flow scenery had been recorded by an off-the-shelf action camera mounted to a low-cost quadcopter, and video frames were ortho-rectified to sizes of 4482×2240 px2 at a scale of 64 px/m. The new velocimetry approach is as follows: An adaptive Gaussian mixture model is used for video background subtraction. Then, scale-invariant keypoints on each remaining binary foreground image frame are determined by a feature detection algorithm, and corresponding feature points in subsequent frame pairs are matched using the iterative random sample consensus method. The related feature shifts in metric space divided by the video frame rate finally give the velocity vectors. The obtained velocimetry fields are compared with findings from both a particle image velocimetry and particle tracking velocimetry analysis in terms of accuracy and needed computational power. Indication is given that the feature tracking algorithm presents slightly less precise results, but clearly outperforms the other two in relation to computational power. Therefore, the new simplified method provides a high potential tool that may enable a future way to real time surface velocity measurements obtained from unmanned airborne vehicles.

Time-resolved particle image velocimetry measurements with sufficient spatial resolutions combined with coherence spectrum analysis were adopted to investigate the geometric and kinematic features of wall-attached motions in open channel flows. Results indicate that the diagnosed streamwise wavelength of wall-attached motions λxWA based on a given near zero coherence spectrum threshold exhibits a constant streamwise wavelength/wall-normal distance ratio accompanied with a roughly constant inclination angle within y+ > ∼100 and y/h ≤ 0.7 [y+ is the inner-scale normalized distance to the wall y with y+ = y/(ν/uτ) (ν is the kinematic viscosity and uτ is the friction velocity) and h is the water depth], meaning that they are geometrically self-similar. However, in the free-surface region, where y/h > 0.7, the diagnosed wall-attached motions are non-self-similar with λxWA increasing more dramatically and reaching up to ∼20h at the free surface, which is comparable to the typical scales of very-large-scale motions therein. The wall-attached motions are demonstrated to be both energetic and stress active. Within y/h < 0.7, the wall-attached motions with the streamwise wavelength greater than λxWA (including both the self-similar and non-self-similar wavelength range portions) carry more than 40% of the streamwise turbulent kinetic energy (TKE) and 30% of Reynolds shear stress. Beyond y/h = 0.7, where the self-similar portions vanish, all the wall-attached motions are non-self-similar wall-attached motions, which themselves still maintain considerable strength even at the free surface and contribute to 25% of the streamwise TKE and 10% of the Reynolds shear stress therein. [ABSTRACT FROM AUTHOR]

This study experimentally examined the turbulent characteristics of decelerating open-channel flow based on particle imaging velocimetry measurement. The decelerating flow shows a similar velocity profile to that in uniform flow, but it exhibits greater turbulence intensity and Reynolds stress. Statistical evidence of the presence of very-large-scale motions (VLSMs) in decelerating open-channel flows was presented for the first time. The results indicate that VLSMs in decelerating flows can survive further away from the wall when compared to other wall-turbulence flows. The contribution rate of the VLSMs to the turbulent kinetic energy and the Reynolds stress in the decelerating open-channel flow is slightly lower than that in channels, boundary layers, and pipe flows. [ABSTRACT FROM AUTHOR]