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Data-driven materials design informed by legacy data-sets can enable the education of a new workforce, promote openness of the scientific process in the community, and advance our physical understanding of complex material systems. The performance of structural materials, which are controlled by competing factors of composition, grain size, particle size/distribution, residual strain, cannot be modelled with single-mechanism physics. The design of optimal processing route must account for the coupled nature of the creation of such factors, and requires students to learn machine learning and statistical modelling principles not taught in the conventional undergraduate or graduate level Materials Science and Engineering curricula. Therefore, modified curricula with opportunities for experiential learning are paramount for workforce development. Projects with real-world data provide an opportunity for students to establish fluency in the iterative steps needed to solve relevant scientific and engineering process design questions.
The aim of this paper is to introduce a new stochastic order based on the residual lifetimes of two nonnegative dependent random variables and the stochastic precedence order. We develop some characterizations and preservation properties of this stochastic order. In addition, we study some of its reliability properties and its relation with other existing stochastic orders. One of the possible applications in reliability theory has also been discussed.
Velvetleaf is an economically important weed in popcorn production fields in Nebraska. Many PRE herbicides in popcorn have limited residual activity or provide partial velvetleaf control. There are a limited number of herbicides applied POST in popcorn compared to field corn, necessitating the evaluation of POST herbicides for control of velvetleaf. The objectives of this study were to (1) evaluate the efficacy and crop safety of labeled POST herbicides for controlling velvetleaf that survived S-metolachlor/atrazine applied PRE and (2) determine effect of velvetleaf height on POST herbicide efficacy, popcorn injury, and yield. Field experiments were conducted in 2018 and 2019 near Clay Center, Nebraska. The experiments were arranged in a split-plot design with four replications. The main plot treatments were velvetleaf heights (up to 15 cm and up to 30 cm) and sub-plot treatments included a no-POST herbicide control, and eleven POST herbicide programs. Fluthiacet-methyl, fluthiacet-methyl/mesotrione, carfentrazone-ethyl, dicamba, and dicamba/diflufenzopyr provided > 96% velvetleaf control 28 DAT, reduced velvetleaf density to < 7 plants m─2, achieved 99 to 100% biomass reduction, and no effect on popcorn yield. Herbicide programs tested in this study provided > 98% control of velvetleaf 28 DAT in 2019. Most POST herbicide programs in this study provided > 90% control of up to 15 cm and up to 30 cm velvetleaf and no differences between velvetleaf heights in density, biomass reduction, or popcorn yield were observed, except topramezone and nicosulfuron/mesotrione 28 d after treatment (DAT) in 2018. Based on contrast analysis, herbicide programs with fluthiacet-methyl or dicamba provided better control than herbicide programs without them at 28 DAT in 2018. It is concluded that POST herbicides are available for control of up to 30 cm tall velvetleaf in popcorn production fields.
In his 2018 presidential address to the Society of Business Ethics, Jeffery Smith claimed that political approaches to business ethics must be attentive to both the distinctive nature of commercial activity and, at the same time, the degree to which such commercial activity is structured by political decisions and choices. In what we take to be a friendly extension of the argument, we claim that Smith does not go far enough with this insight. Smith’s political approach to business ethics focuses solely on the outcomes of political choices. But if we think of politics in terms of processes—as in, ongoing disagreement and contest—and not merely a series of legal, administrative, or institutional outcomes, a different view of business ethics emerges. In particular, we argue that such an emphasis points us toward seeing business actors as having a normative duty to preserve the integrity and functioning of democracy.
This article presented a compact bandpass filter with wide-stopband performance. Two substrate integrated waveguide (SIW) cavities and a short-circuited coplanar line introduced between the two cavities are used to realize a compact third-order bandpass filter. The passband is generated by combining the resonant frequency of TE101 mode of the SIW cavities and the fundamental resonant frequency of the short-circuited coplanar line. The size of the proposed filter reduces significantly in comparison with conventional third-order SIW filters. Moreover, the center frequency (CF) and the bandwidth of the filter can be controlled by adjusting the structural parameters of the filter. In addition, the first higher-order mode TE102 of the SIW cavity is suppressed by minimizing the coupling of TE102 mode in order to obtain wide-stopband performance. The proposed filter is designed, fabricated, and measured, and the simulation and measurement results show a good agreement. The filter exhibits compact size, low loss, and a rejection higher than 20 dB up to 1.94f0.
Survivors of natural disasters are at risk for mental health sequela, including deficits in neurocognitive functioning. This study explores links between hurricane exposure and resulting psychiatric symptoms and deficits in cognitive processing, attention, learning, and memory.
Relocated Katrina survivors and demographically matched controls completed neurocognitive tests assessing processing speed (Trail Making Test, Part A), mental flexibility (Trail Making Test, Part B), sustained attention (Conner’s Continuous Performance Test), and learning and memory (Rey Auditory-Verbal Learning Test). PTSD (Clinician-Administered PTSD Scale) and depressive symptoms (BDI- II) were also measured.
Survivors had more PTSD and depression symptoms and weaker performance in cognitive processing, mental flexibility, and sustained attention, but not memory and learning compared to controls. When controlling for depression and PTSD symptoms (analysis of covariances), only CPT-II response time remained significantly different for survivors, so that sustained attention deficits were independent of emotional symptoms.
Survivors had more psychiatric symptoms and neurocognitive dysfunctions than controls in most assessed measures. Our study had mixed results in identifying cognitive deficits related to psychopathology. Results suggest that disaster survivors, even those without psychopathology, should be assessed for cognitive issues that may affect their ability to process post-disaster instructions and access assistance in recovery efforts.
The scalp electroencephalogram (EEG) signals detect the extracellular electrical field generated by the columns underneath the electrodes closer to the cortical surface and represent near-synchronous summated potentials (excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP)) generated by these columns of the cerebral cortex.1–4
This work analyses the viscous flow and elastic deformation created by the forced axial motion of a rigid cylinder within an elastic liquid-filled tube. The examined configuration is relevant to various minimally invasive medical procedures in which slender devices are inserted into fluid-filled biological vessels, such as vascular interventions, interventional radiology, endoscopies and laparoscopies. By applying the lubrication approximation, thin shell elastic model, as well as scaling analysis and regular and singular asymptotic schemes, the problem is examined for small and large deformation limits (relative to the gap between the cylinder and the tube). At the limit of large deformations, forced insertion of the cylinder is shown to involve three distinct regimes and time scales: (i) initial shear dominant regime, (ii) intermediate regime of dominant fluidic pressure and a propagating viscous-peeling front, (iii) late-time quasi-steady flow regime of the fully peeled tube. A uniform solution for all regimes is presented for a suddenly applied constant force, showing initial deceleration and then acceleration of the inserted cylinder. For the case of forced extraction of the cylinder from the tube, the negative gauge pressure reduces the gap between the cylinder and the tube, increasing viscous resistance or creating friction due to contact of the tube and cylinder. Matched asymptotic schemes are used to calculate the dynamics of the near-contact and contact limits. We find that the cylinder exits the tube in a finite time for sufficiently small or large forces. However, for an intermediate range of forces, the radial contact creates a steady locking of the cylinder inside the tube.
Resistance to colistin, a last resort antibiotic, has emerged in India. We investigated colistin-resistant Klebsiella pneumoniae(ColR-KP) in a hospital in India to describe infections, characterize resistance of isolates, compare concordance of detection methods, and identify transmission events.
Retrospective observational study.
Case-patients were defined as individuals from whom ColR-KP was isolated from a clinical specimen between January 2016 and October 2017. Isolates resistant to colistin by Vitek 2 were confirmed by broth microdilution (BMD). Isolates underwent colistin susceptibility testing by disk diffusion and whole-genome sequencing. Medical records were reviewed.
Of 846 K. pneumoniae isolates, 34 (4%) were colistin resistant. In total, 22 case-patients were identified. Most (90%) were male; their median age was 33 years. Half were transferred from another hospital; 45% died. Case-patients were admitted for a median of 14 days before detection of ColR-KP. Also, 7 case-patients (32%) received colistin before detection of ColR-KP. All isolates were resistant to carbapenems and susceptible to tigecycline. Isolates resistant to colistin by Vitek 2 were also resistant by BMD; 2 ColR-KP isolates were resistant by disk diffusion. Moreover, 8 multilocus sequence types were identified. Isolates were negative for mobile colistin resistance (mcr) genes. Based on sequencing analysis, in-hospital transmission may have occurred with 8 case-patients (38%).
Multiple infections caused by highly resistant, mcr-negative ColR-KP with substantial mortality were identified. Disk diffusion correlated poorly with Vitek 2 and BMD for detection of ColR-KP. Sequencing indicated multiple importation and in-hospital transmission events. Enhanced detection for ColR-KP may be warranted in India.
Glyphosate-resistant (GR) horseweed is one of the most common and troublesome weeds in soybean production fields in several states in the United States, including Nebraska. The evolution of horseweed resistant to several herbicide sites of action has prioritized an integrated approach, including tillage, for effective management of this problem weed. The objectives of this study were to evaluate the effect of tillage or herbicide applied in fall or spring followed by a PRE, POST, and PRE followed by a POST herbicide program for GR horseweed control as well as GR soybean injury and yield in Nebraska. Field studies were established in the fall 2014–2015 and 2015–2016 growing seasons using a factorial randomized complete block design with shallow tillage or herbicide applied at different timings as two factors. Shallow tillage was accomplished using a 50-cm-wide rototiller operated at a depth of 10 cm. At soybean harvest, tillage applied the previous year in fall or spring without any follow-up herbicide treatment provided 79% to 88% horseweed control compared with 27% and 56% control with 2,4-D plus carfentrazone applied in fall and spring, respectively. Tillage or herbicide applied in fall or spring followed by a PRE, POST, or PRE and POST herbicide provided 82% to 99% GR horseweed control at soybean harvest. Soybean yield in this study was similar in most treatments. Tillage or herbicide applied in fall or spring provided similar horseweed control and soybean yield when followed by a PRE, POST, or PRE and POST herbicide; therefore, fall- or spring-applied herbicides can be rotated with shallow tillage for integrated season-long horseweed management.
Despite extensive research, symptom structure of posttraumatic stress disorder (PTSD) is highly debated. The network approach to psychopathology offers a novel method for understanding and conceptualizing PTSD. However, extant studies have mainly used small samples and self-report measures among sub-clinical populations, while also overlooking co-morbid depressive symptoms.
PTSD symptom network topology was estimated in a sample of 1489 treatment-seeking veteran patients based on a clinician-rated PTSD measure. Next, clinician-rated depressive symptoms were incorporated into the network to assess their influence on PTSD network structure. The PTSD-symptom network was then contrasted with the network of 306 trauma-exposed (TE) treatment-seeking patients not meeting full criteria for PTSD to assess corresponding network differences. Finally, a directed acyclic graph (DAG) was computed to estimate potential directionality among symptoms, including depressive symptoms and daily functioning.
The PTSD symptom network evidenced robust reliability. Flashbacks and getting emotionally upset by trauma reminders emerged as the most central nodes in the PTSD network, regardless of the inclusion of depressive symptoms. Distinct clustering emerged for PTSD and depressive symptoms within the comorbidity network. DAG analysis suggested a key triggering role for re-experiencing symptoms. Network topology in the PTSD sample was significantly distinct from that of the TE sample.
Flashbacks and psychological reactions to trauma reminders, along with their strong connections to other re-experiencing symptoms, have a pivotal role in the clinical presentation of combat-related PTSD among veterans. Depressive and posttraumatic symptoms constitute two separate diagnostic entities, but with meaningful between-disorder connections, suggesting two mutually-influential systems.
In the current research, the application and capability of electric discharge treatment (EDT) for enhancing the cytocompatibility and tribological properties of medical-grade Co–Cr alloy were investigated. The Co–Cr specimens were treated by copper tungsten (Cu–W) electrode in a deionized water tank (dielectric medium) at different spark energy levels. To examine the cytocompatibility of substrates, the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed to evaluate the substrate cell viability. Furthermore, the wear rate and coefficient of friction of the substrates were examined on a pin-on-disc tribometer. In vitro cytocompatibility results revealed that the % viability of the MG-63 cells on EDT sample was approximately two times improved compared with that on the untreated surface. The tribological results showed that the treated samples have better friction reducing properties and four times higher wear resistance compared with unmachined Co–Cr samples. The surface modification at 10 A current and 60 µs pulse on-time and 150 µs off-time were found as significant parameters in both assessments.