A framework for hierarchical, object-oriented simulation modeling of a steel manufacturing enterprise

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project is to combine detailed physical models of industrial processes with unit operations and business-level models. This would allow global and individual process control schemes to be implemented that would facilitate improved overall system performance. Intelligent decision support that employs expert system concepts (knowledge base and rules) could then also be incorporated. This project is innovative because it attempts to incorporate all levels of production-related activities from atoms to enterprise, and to integrate those activities into one comprehensive decision support tool. This project is an interdisciplinary effort requiring enterprise modeling and simulation model integration; process modeling and control; process control and optimization; chemical process modeling; and detailed molecular-level models. It represents the state of the art in enterprise modeling and simulation and incorporates cutting edge process modeling, process control, and system optimization techniques

Clinical correlates of vitamin D deficiency in established psychosis

Background Suboptimal vitamin D levels have been identified in populations with psychotic disorders. We sought to explore the relationship between vitamin D deficiency, clinical characteristics and cardiovascular disease risk factors among people with established psychosis. Methods Vitamin D levels were measured in 324 community dwelling individuals in England with established psychotic disorders, along with measures of mental health, cardiovascular risk and lifestyle choices. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25-OHD) levels below 10 ng/ml (equivalent to 50 nmol/L). Results The mean 25-OHD serum level was 12.4 (SD 7.3) ng/ml, (range 4.0-51.7 ng/ml). Forty nine percent (n = 158) were vitamin D deficient, with only 14 % (n = 45) meeting criteria for sufficiency. Accounting for age, gender, ethnicity and season of sampling, serum 25-OHD levels were negatively correlated with waist circumference (r = −0.220, p < 0.002), triglycerides (r = −0.160, p = 0.024), total cholesterol (r = −0.144, p = 0.043), fasting glucose (r = −0.191, p = 0.007), HbA1c (r = −0.183, p = 0.01), and serum CRP levels (r = −0.211, p = 0.003) and were linked to the presence of metabolic syndrome. Conclusions This is the largest cross sectional study of serum 25-OHD levels in community dwelling individuals with established psychosis, indicating a high level of vitamin D deficiency. Lower vitamin D levels are associated with increased cardiovascular disease risk factors and in particular metabolic syndrome. Further research is needed to define appropriate protocols for vitamin D testing and supplementation in practice to see if this can improve cardiovascular disease risk

Skeletal muscle ACC2 S212 phosphorylation is not required for the control of fatty acid oxidation during exercise

During submaximal exercise fatty acids are a predominant energy source for muscle contractions. An important regulator of fatty acid oxidation is acetyl‐CoA carboxylase (ACC), which exists as two isoforms (ACC1 and ACC2) with ACC2 predominating in skeletal muscle. Both ACC isoforms regulate malonyl‐CoA production, an allosteric inhibitor of carnitine palmitoyltransferase 1 (CPT‐1); the primary enzyme controlling fatty acyl‐CoA flux into mitochondria for oxidation. AMP‐activated protein kinase (AMPK) is a sensor of cellular energy status that is activated during exercise or by pharmacological agents such as metformin and AICAR. In resting muscle the activation of AMPK with AICAR leads to increased phosphorylation of ACC (S79 on ACC1 and S221 on ACC2), which reduces ACC activity and malonyl‐CoA; effects associated with increased fatty acid oxidation. However, whether this pathway is vital for regulating skeletal muscle fatty acid oxidation during conditions of increased metabolic flux such as exercise/muscle contractions remains unknown. To examine this we characterized mice lacking AMPK phosphorylation sites on ACC2 (S212 in mice/S221 in humans‐ACC2‐knock‐in [ACC2‐KI]) or both ACC1 (S79) and ACC2 (S212) (ACC double knock‐in [ACCD‐KI]) during submaximal treadmill exercise and/or ex vivo muscle contractions. We find that surprisingly, ACC2‐KI mice had normal exercise capacity and whole‐body fatty acid oxidation during treadmill running despite elevated muscle ACC2 activity and malonyl‐CoA. Similar results were observed in ACCD‐KI mice. Fatty acid oxidation was also maintained in muscles from ACC2‐KI mice contracted ex vivo. These findings indicate that pathways independent of ACC phosphorylation are important for regulating skeletal muscle fatty acid oxidation during exercise/muscle contractions

Diffusion tensor imaging and arterial tissue: establishing the influence of arterial tissue microstructure on fractional anisotropy, mean diffusivity and tractography

This study investigates diffusion tensor imaging (DTI) for providing microstructural insight into changes in arterial tissue by exploring how cell, collagen and elastin content effect fractional anisotropy (FA), mean diffusivity (MD) and tractography. Five ex vivo porcine carotid artery models (n = 6 each) were compared-native, fixed native, collagen degraded, elastin degraded and decellularised. Vessels were imaged at 7 T using a DTI protocol with b = 0 and 800 s/mm2 and 10 isotopically distributed directions. FA and MD were evaluated in the vessel media and compared across models. FA values measured in native (p < 0.0001), fixed native (p < 0.0001) and collagen degraded (p = 0.0018, p = 0.0016, respectively) were significantly higher than those in elastin degraded and decellularised arteries. Native and fixed native had significantly lower MD values than elastin degraded (p < 0.0001) and decellularised tissue (p = 0.0032, p = 0.0003, respectively). Significantly lower MD was measured in collagen degraded compared with the elastin degraded model (p = 0.0001). Tractography yielded helically arranged tracts for native and collagen degraded vessels only. FA, MD and tractography were found to be highly sensitive to changes in the microstructural composition of arterial tissue, specifically pointing to cell, not collagen, content as the dominant source of the measured anisotropy in the vessel wall

Miscellaneous Problems

Contains reports on five research projects

Miscellaneous Problems

Contains reports on eight research projects

Acceptability of a theory-based sedentary behaviour reduction intervention for older adults ('On Your Feet to Earn Your Seat').

Background: Adults aged 60 years and over spend most time sedentary and are the least physically active of all age groups. This early-phase study explored acceptability of a theory-based intervention to reduce sitting time and increase activity in older adults, as part of the intervention development process. Methods: An 8-week uncontrolled trial was run among two independent samples of UK adults aged 60–75 years. Sample 1, recruited from sheltered housing on the assumption that they were sedentary and insufficiently active, participated between December 2013 and March 2014. Sample 2, recruited through community and faith centres and a newsletter, on the basis of self-reported inactivity (<150 weekly minutes of moderate-to-vigorous activity) and sedentary behaviour (≥6 h mean daily sitting), participated between March and August 2014. Participants received a booklet offering 16 tips for displacing sitting with light-intensity activity and forming activity habits, and self-monitoring ‘tick-sheets’. At baseline, 4-week, and 8-week follow-ups, quantitative measures were taken of physical activity, sedentary behaviour, and habit. At 8 weeks, tick-sheets were collected and a semi-structured interview conducted. Acceptability was assessed for each sample separately, through attrition and adherence to tips, ANOVAs for behaviour and habit changes, and, for both samples combined, thematic analysis of interviews. Results: In Sample 1, 12 of 16 intervention recipients completed the study (25 % attrition), mean adherence was 40 % (per-tip range: 15–61 %), and there were no clear patterns of changes in sedentary or physical activity behaviour or habit. In Sample 2, 23 of 27 intervention recipients completed (15 % attrition), and mean adherence was 58 % (per-tip range: 39–82 %). Sample 2 decreased mean sitting time and sitting habit, and increased walking, moderate activity, and activity habit. Qualitative data indicated that both samples viewed the intervention positively, found the tips easy to follow, and reported health and wellbeing gains. Conclusions: Low attrition, moderate adherence, and favourability in both samples, and positive changes in Sample 2, indicate the intervention was acceptable. Higher attrition, lower adherence, and no apparent behavioural impact among Sample 1 could perhaps be attributable to seasonal influences. The intervention has been refined to address emergent acceptability problems. An exploratory controlled trial is underway

GRB 180418A:A Possibly Short Gamma-Ray Burst with a Wide-angle Outflow in a Faint Host Galaxy

We present X-ray and multiband optical observations of the afterglow and host galaxy of GRB 180418A, discovered by Swift/BAT and Fermi/GBM. We present a reanalysis of the GBM and BAT data deriving durations of the prompt emission of T 90 ≈ 2.56 and 1.90 s, respectively. Modeling the Fermi/GBM catalog of 1405 bursts (2008-2014) in the hardness-T 90 plane, we obtain a probability of ≈60% that GRB 180418A is a short-hard burst. From a combination of Swift/XRT and Chandra observations, the X-ray afterglow is detected to ≈38.5 days after the burst and exhibits a single power-law decline with F X ∝ t -0.98. Late-time Gemini observations reveal a faint r ≈ 25.69 mag host galaxy at an angular offset of ≈0.″16. At the likely redshift range of z ≈ 1-2.25, we find that the X-ray afterglow luminosity of GRB 180418A is intermediate between short and long gamma-ray bursts (GRBs) at all epochs during which there are contemporaneous data and that GRB 180418A lies closer to the E γ,peak-E γ,iso correlation for short GRBs. Modeling the multiwavelength afterglow with the standard synchrotron model, we derive the burst explosion properties and find a jet opening angle of θ j 9°-14°. If GRB 180418A is a short GRB that originated from a neutron star merger, it has one of the brightest and longest-lived afterglows along with an extremely faint host galaxy. If, instead, the event is a long GRB that originated from a massive star collapse, it has among the lowest-luminosity afterglows and lies in a peculiar space in terms of the hardness-T 90 and E γ,peak-E γ,iso planes. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Peer norm guesses and self-reported attitudes towards performance-related pay

Due to a variety of reasons, people see themselves differently from how they see others. This basic asymmetry has broad consequences. It leads people to judge themselves and their own behavior differently from how they judge others and others’ behavior. This research, first, studies the perceptions and attitudes of Greek Public Sector employees towards the introduction of Performance-Related Pay (PRP) systems trying to reveal whether there is a divergence between individual attitudes and guesses on peers’ attitudes. Secondly, it is investigated whether divergence between own self-reported and peer norm guesses could mediate the acceptance of the aforementioned implementation once job status has been controlled for. This study uses a unique questionnaire of 520 observations which was designed to address the questions outlined in the preceding lines. Our econometric results indicate that workers have heterogeneous attitudes and hold heterogeneous beliefs on others’ expectations regarding a successful implementation of PRP. Specifically, individual perceptions are less skeptical towards PRP than are beliefs on others’ attitudes. Additionally, we found that managers are significantly more optimistic than lower rank employees regarding the expected success of PRP systems in their jobs. However, they both expect their peers to be more negative than they themselves are