Non-Equilibrium Modeling of the Fe XVII 3C/3D ratio for an Intense X-ray Free Electron Laser

We present a review of two methods used to model recent LCLS experimental results for the 3C/3D line intensity ratio of Fe XVII (Bernitt et al. 2012), the time-dependent collisional-radiative method and the density-matrix approach. These are described and applied to a two-level atomic system excited by an X-ray free electron laser. A range of pulse parameters is explored and the effects on the predicted Fe XVII 3C and 3D line intensity ratio are calculated. In order to investigate the behavior of the predicted line intensity ratio, a particular pair of A-values for the 3C and 3D transitions was chosen (2.22 $\times$ 10$^{13}$ s$^{-1}$ and 6.02 $\times$ 10$^{12}$ s$^{-1}$ for the 3C and 3D, respectively), but our conclusions are independent of the precise values. We also reaffirm the conclusions from Oreshkina et al.(2014, 2015): the non-linear effects in the density matrix are important and the reduction in the Fe XVII 3C/3D line intensity ratio is sensitive to the laser pulse parameters, namely pulse duration, pulse intensity, and laser bandwidth. It is also shown that for both models the lowering of the 3C/3D line intensity ratio below the expected time-independent oscillator strength ratio has a significant contribution due to the emission from the plasma after the laser pulse has left the plasma volume. Laser intensities above $\sim 1\times 10^{12}$ W/cm$^{2}$ are required for a reduction in the 3C/3D line intensity ratio below the expected time independent oscillator strength ratio

Product selling vs. pay-per-use service: a strategic analysis of competing business models

We present a model that suggests possible explanations for the observed proliferation of “pay-per-use" (PPU) business models over the last two decades. Delivering “fractions" of a product as a service offers a cost advantage to customers with lower usage but requires extra delivery costs. Previous research focused on information goods (with negligible production costs) and predicted that PPU, when arising as a differentiation to selling in equilibrium, fundamentally achieves lower profits than selling. We extend the theory by covering goods with any production cost, in duopolistic competition. We show that PPU business models can be more profitable than selling (especially at mid-range production costs), as long as their delivery costs are not too high, a requirement that is more easily fulfilled as new technologies reduce these costs. Moreover, if firms are imperfectly informed about their customers' usage profiles, PPU's effective pricing of customers' varying usage offers an additional advantage over selling. This requires companies to employ accounting methods that do not inappropriately allocate production costs over stochastic usage levels. If PPU service provision suffers from queueing inefficiencies, this does not fundamentally change the relative profitability of the PPU and selling models, provided that PPU providers can attract sufficiently high demand to benefit from pooling economies

Variation in enamel mechanical properties throughout the crown in catarrhine primates.

Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen primate lower molars representing fourteen taxa (catarrhine, n = 13; platyrrhine, n = 1) were sectioned in the lingual-buccal plane through the mesial cusps. Gradients of enamel mechanical properties, specifically hardness and elastic modulus, were quantified using nanoindentation from inner (near the enamel-dentine junction), through middle, to outer enamel (near the outer enamel surface) at five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral). Cuspal positions had higher mechanical property values than lateral positions. Middle enamel had higher mean hardness and elastic modulus values than inner and outer locations in all five crown positions. Functionally, the thicker-enameled buccal cusps of lower molars did not show evidence of increased resistance to failure; instead, lingual cusps-which show higher rates of fracture-had higher average mechanical property values, with no significant differences observed between sides. Preliminary phylogenetic results suggest there is relatively little phylogenetic signal in gradients of mechanical properties through the enamel or across the crown. There appears to be common mechanical property patterns across molar crowns in Catarrhini and potentially among primates more broadly. These results may allow more precise interpretations of dental biomechanics and processes resulting in mechanical failure of enamel in primates, such as wear and fracture. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Blister beetle management in alfalfa

"In Missouri, blister beetles are an infrequent pest of alfalfa. When present in sufficient numbers, however, the consequences can be serious. These insects cause only limited plant damage to alfalfa and soybeans. But when ingested by livestock, especially horses, the animals may become sick and even die. These insects produce a highly toxic drug called cantharidan."--First page.Wayne C. Bailey and Wilbur R. Enns (Department of Entomology), and Wayne E. Loch (Department of Animal Science, College of Agriculture)Revised 1/90/6

Tissue-specific cytokine release from human extra-placental membranes stimulated by lipopolysaccharide in a two-compartment tissue culture system

<p>Abstract</p> <p>Background</p> <p>The extra-placental gestational membranes secrete cytokines in response to bacteria and other infectious agents, with potentially adverse consequences for pregnancy. The present study used lipopolysaccharide (LPS) as a prototype endotoxin to investigate the pattern of stimulated cytokine release from the amniotic and choriodecidual sides of full-thickness human gestational membranes in a two-compartment tissue culture system.</p> <p>Methods</p> <p>Gestational membranes were collected from healthy non-laboring caesarean deliveries at term. Full-thickness membranes from each placenta were cut into pieces, mounted on Transwell frames, and placed in culture wells to create a two-compartment culture with the gestational membranes serving as the barrier between compartments. The LPS (100 ng/ml) was added to the amniotic, choriodecidual or both chambers of the culture, and cytokines were assayed in the medium of the amniotic and choriodecidual chambers after 8 h of LPS exposure. Cytokine concentrations were analyzed by two-way analysis of variance for effects of treatment and side specificity of cytokine release from the membranes.</p> <p>Results</p> <p>LPS exposure on the choriodecidual side of the membranes significantly increased TNF-alpha, IL-6, IL-10 and IL-8 in the choriodecidual compartment, whereas TNF-alpha was the only cytokine observed to increase in the amniotic compartment. When LPS treatment was to the amniotic side of the membranes, there were significant increases in TNF-alpha and IL-6 in the amniotic compartment as well as increased concentrations of TNF-alpha, IL-6 and IL-8 in the choriodecidual compartment; however, there were no statistically significant differences for IL-10 in either compartment. No statistically significant differences were observed for IL-1beta, TGF-beta or IL-4 concentrations in response to LPS, regardless of the exposure modality.</p> <p>Conclusion</p> <p>The amnion and choriodecidua exhibited distinct patterns of response to LPS with evidence of inflammatory signaling across the layers of the gestational membranes. These results suggest a complicated network of signaling within the gestational membranes, in which cytokine- and tissue-specific responses to inflammatory stimulation may have important implications for maintaining pregnancy in the challenge of microbial invasion of the uterine compartment.</p

Updating "small world representations" in strategic decision-making under extreme uncertainty

The behavioral strategy literature investigates how decision makers might use Small World Representations (SWRs) to guide their actions in situations of extreme uncertainty, but says little about how such representations should be updated during the implementation phase. In this paper, we provide a framework to capture the relationship between SWRs, unknowns and Black Swans, and, drawing on the psychology of reasoning literature, explore different heuristic methods of inquiry that decision makers might use to update their SWRs. We compare the performance of two such methods⎯disconfirmation and counterfactual reasoning⎯in highly uncertain situations characterized by ambiguous and non-definite information. We find that counterfactual reasoning is superior to disconfirmation with respect to (1) counteracting the confirmation bias, (2) promoting the exploration of the scenario space, and (3) favoring the adoption of actions able to mitigate or exploit the consequences of Black Swans

Use of laboratory-scale rill and interill erodibility measurements for the prediction of hillslope-scale erosion on rehabilitated coal mine soils and overburdens

Prediction of hillslope-scale soil erosion traditionally involves extensive data collection from field plots under natural rainfall, or from field rainfall simulation programs. Recognising the high costs and inconvenience associated with field-based studies, a method was developed and tested for predicting hillslope-scale soil erosion from laboratory-scale measurements of erodibility. A laboratory tilting flume and rainfall simulator were used to determine rill and interill erodibility coefficients for 32 soils and overburdens from Queensland open-cut coal mines. Predicted sediment delivery rates based on laboratory determinations of erodibility were tested against field measurements of erosion from 12-m-long plots under simulated rainfall at 100 mm/h on slopes ranging from 5% to 30%. Regression analysis demonstrated a strong relationship between predicted and measured sediment delivery rates, giving an r2 value of up to 0.74, depending on the particular modeling approach used. These results demonstrate that soil losses due to the combined processes of rill and interill erosion at the hillslope scale can successfully be predicted from laboratory-scale measurements of erodibility, provided a suitable methodology and modelling approach is adopted. The success of this approach will greatly reduce the cost and effort required for prediction of hillslope scale soil erosion

Study Abroad as an Education Experience: Challenges, Realizations, and Lessons Learned

Study abroad programs can represent an important component of an Information Systems (IS) education. This article presents the views of five scholars on study abroad education. These views are based on their experiences leading such programs, and were presented during a panel session at the America’s Conference on Information Systems (AMCIS) 2010 in Lima, Peru. The panel discussed short-term (seven to fourteen days), medium-term (fourteen to thirty days), and long-term study abroad experiences. In addition, the panelists touched on the logistical issues related to leading a study abroad trip, and on lessons learned by the panelists

Management succession and success in a professional soccer team

Research into sports team performance has shown that across many sports and league competitions, teams that change their coaches after a decline in performance do rebound, but fare no better on average than teams that have not changed their coach in a similar situation. A similar lack of succession benefits has been reported in studies of manager and CEO succession: it has not been established that changing a team's leader improves a declining team's performance. We study the effect of a change of coach on the performance of a professional soccer team. Based on rarely obtained access to a whole season (one year) of daily close observation of the team and coaching staff in practice and matches, this study uses quantitative and qualitative data to go beyond the "average" pattern reported in the literature. We document in detail how, in a single team case study over an entire season, the processes in leadership behavior changed with a change of coach, the effect this had on the state of mind of the team, how the match behaviors of the players changed, and how these changes translated into improved performance. The process effects of a leadership change on the performance of a sports team may hold insights for leader succession in management: in addition to the aggregate organizational and experience fit of the new team leader, the specific leadership processes introduced by the new leader are critical for performance effects