Balancing and model reduction for discrete-time nonlinear systems based on Hankel singular value analysis

This paper is concerned with balanced realization and model reduction for discrete-time nonlinear systems. Singular perturbation type balanced truncation method is proposed. In this procedure, the Hankel singular values and the related controllability and observability properties are preserved, which is a natural generalization of both the linear discrete-time case and the nonlinear continuous-time case.

Perceptions of Non-university Affiliated Dietetic Internship Program Directors Regarding Education Requirements to Obtain a Master’s Degree as an Entry-level Dietitian

Purpose: The Commission on Dietetic Registration announced that entry-level eligibility requirements to become a registered dietitian would increase to include obtaining a Master’s degree. The objective of this study was to explore perceptions of non-university affiliated dietetic internship program directors regarding proposed education requirements. Methods: Directors participated in a phone survey of structured questions related to the topic. The population of focus was non-university affiliated dietetic internship program directors. Results: Program directors expressed viewpoints of positive, negative, and mixed regarding the increase in education requirements. Diversity and autonomy were among concerns expressed by program directors. Conclusion: The research found that this subset of stake holders remains conflicted with the decision by the Commission on Dietetic Registration that a Master’s degree would be the entry-level requirement to become a registered dietitian

Correction to: protease-activated receptors (PARs): mechanisms of action and potential therapeutic modulators in PAR-driven inflammatory diseases

Following the publication of this article [1], the authors reported an incorrect citation in the following sentence in the “Metalloproteases” sub-section

The Isospin Distribution of Fragments in Reactions 96Ru+96Ru, 96Ru+96Zr, 96Zr+96Ru, and 96Zr+96Zr at Beam Energy 400 AMeV

The isospin distribution of particles and fragments in collisions 96Ru+96Ru, 96Ru+96Zr, 96Zr+96Ru, and 96Zr+96Zr at beam energy 400 AMeV is studied with isospin dependent QMD model. We find that the rapidity distribution of differential neutron-proton counting in neutron rich nucleus-nucleus collisions at intermediate energies is sensitive to the isospin dependent part of nuclear potential. The study of the N/Z ratio of nucleons, light charged particles (LCP) and intermediate mass fragments (IMF) shows that the isospin dependent part of nuclear potential drives IMF to be more isospin symmetric and emitted nucleons to be more neutron rich. From the study of the time evolution of the isospin distribution in emitted nucleons, LCP and IMF we find that neutrons diffuse much faster than protons at beginning and the final isospin distribution is a result of dynamical balance of symmetry potential and Coulomb force under the charge conservation.Comment: 10 pages, 5 figure

Dealing with doping. A plea for better science, governance and education.

The creation of WADA contributed to harmonization of anti-doping and changed doping behavior and prevalence in the past 22 years. However, the system has developed important deficiencies and limitations that are causing harm to sports, athletes and society. These issues are related to the lack of evidence for most substances on the Prohibited List for performance or negative health effects, a lack of transparency and accountability of governance and decision-making by WADA and the extension of anti-doping policies outside the field of professional sports. This article tries to identify these deficiencies and limitations and presents a plea for more science, better governance and more education. This should lead to a discussion for reform among stakeholders, which should cover support of a new Prohibited List by actual research and evidence and introduce better governance with accountable control bodies and regulation. Finally, comprehensive education for all stakeholders will be the basis of all future positive improvements

Weight Changes Post-Phentermine Use

Purpose: Evaluate weight maintenance in subjects who lost weight while taking phentermine (PTM). Methods: This study was conducted by utilizing a validated survey to collect self-reported data about weight changes post-PTM use. The survey was sent to 19,986 email addresses of current and former patients of a PTM-based outpatient clinic, located in Chicago, IL; 546 participants completed the survey. Results were analyzed using a variety of techniques. Results: At the time of the survey, 42% of responders maintained all the weight lost while on PTM, and 25.2% had maintained a weight loss of at least 10% of their body weight. The average weight lost and maintained at the time of the survey was 3.75% ± 13.8% of body weight or 8.74 lbs ± 27.45 lbs. Nineteen responders had no net weight change. Fifty-nine responders reported a net weight gain, ranging from 2 to 70 lbs with a mean net weight gain of 16.07 lbs ± 13.87 lbs. The duration of time since discontinuing PTM use had a significant correlation with weight maintenance: r = 0.340, p value = .000. There was no significant correlation between duration of time using PTM and weight maintenance. No correlations were identified between education, income, or ethnicity and weight maintenance. A correlation was identified between weight maintenance and current exercise level: r = 0.218, p value = .000. Conclusions: Although more research is needed, with the results of this study, the investigators suggest that post-PTM use, weight regain is not significantly higher than weight regain through other weight loss programs. In order to achieve long-term weight loss maintenance, it may behoove patients to receive professional guidance about behavior modifications to maintain weight lost, particularly related to exercise and dietary changes. The investigators of this study suggest greater emphasis on behavior modification in patients taking PTM is indicated

Generation of three iPSC lines from two patients with heterozygous FOXF1 mutations associated to Alveolar Capillary Dysplasia with Misalignment of the Pulmonary Veins

Diagnosing Alveolar Capillary Dysplasia with Misalignment of the Pulmonary Veins (ACD/MPV) based on a genetic alteration in the FOXF1 gene, is complicated by the poor understanding of the causal relation between FOXF1 variants and the ACD/MPV phenotype. Here, we report the generation of human iPSC lines from two ACD/MPV patients, each carrying a different heterozygous FOXF1 mutation, which enables disease modeling for further research on the effect of FOXF1 variants in vitro. The iPSC lines were generated from skin fibroblasts using the non-integrating Sendai virus. The lines expressed pluripotency genes, retained the heterozygous mutation and were capable of trilineage differentiation

Maximizing the Mitigation Potential of Curtailed Wind: A Comparison Between Carbon Capture and Utilization, and Direct Air Capture Processes for the UK

Carbon capture and storage (CCS) with fossil fuel or biomass plants (BECCS) is considered a critical technology to meet mitigation targets set by the Paris Agreement1. However, several drawbacks including high upfront investment costs, significant energy penalty and long-term permanent storage challenges have limited the uptake of CCS on the required scale. Carbon capture and utilisation (CCU) provides an alternative route to recycle CO2 into chemical feedstock and/or synthetic transport fuels (e.g. methanol, DME) that can displace fossil-derived fuels. As the carbon is only transformed, CCU must be integrated with capture/storage to actually offset subsequent emissions from the vehicles consuming them. The mitigation of decentralised emissions poses significant challenges and necessitates the use of carbon dioxide removal technologies (CDR), one of which is direct capture of CO2 from the atmosphere (DAC). The last decade has seen increasing penetration of wind power in the UK electricity system to meet mitigation targets. Because of this, periods of surplus wind generation and low demand or limited/full storage capacity arise. Constraint payments then have to be made to wind farms to curtail generation. This work investigates two possible options to achieve mitigation with this curtailed electricity. In Process A, curtailed electricity is used to produce electrolytic hydrogen and operate methanol synthesis plants. It is then integrated with a direct air capture (DAC) plant to recapture and recycle emissions from the vehicles. Process B assumes curtailed electricity is used to run a DAC plant directly in order to capture decentralised carbon emissions and provide CO2 feedstock for CCU processes. The UK was used as a case study and the methanol synthesis process described by Rihko-Struckmann et al.2 was used as the reference. A range of energy requirements for DAC are cited in literature; the lower and upper bounds of 6.7 GJ/tCO2 and 12.6 GJ/tCO23, respectively, were used. This work has taken a base case curtailment level of 2.5% of the UK total electricity demand, which is equivalent to 390 GWh/y4. Both processes have been compared on the basis of mitigation potential, defined by the proportion of CO2 emissions from gasoline vehicles that are avoided, and mitigation costs per tonne of CO2 captured. Process A resulted in avoiding 0.12% of gasoline emissions (~0.05 MtCO2/y). Surplus energy (~64% of the curtailed electricity) was required to run the DAC plant and an associated air separation unit. The mitigation of potential of Process B was 0.10% or 0.18%, depending on energy requirement used. Therefore, the process that maximises mitigation potential depends on the DAC process considered; using the lower-bound energy requirement, surplus electricity for DAC only is preferable. Neither process is economically viable. CCU costs ($905/tCO2) were found to be double the DAC-only costs ($449/tCO2), mainly due to high H2 costs. It will remain financially-unattractive unless the methanol production becomes profitable. This is unlikely as it requires methanol price to almost double, a carbon price of $313/t to be in effect, or H2 price to reduce to a third of today’s price to$1800/t. References 1. IPCC. Climate Change 2014: Mitigation of Climate Change. Working Group III Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (2014). doi:10.1017/CBO9781107415416 2. Rihko-Struckmann, L. K., Peschel, A., Hanke-Rauschenbach, R. & Sundmacher, K. Assessment of methanol synthesis utilizing exhaust CO2 for chemical storage of electrical energy. Ind. Eng. Chem. Res. 49, 11073–11078 (2010). 3. Socolow, R. et al. Direct Air Capture of CO 2 with Chemicals Panel on Public Affairs. Am. Phys. Soc. - Panel Public Aff. 100 (2011). 4. Messiou, A. Centre for Environmental Policy Investigating the role of power storage in accommodating the future wind. (2012)