Optimal Topology Design for Disturbance Minimization in Power Grids

The transient response of power grids to external disturbances influences their stable operation. This paper studies the effect of topology in linear time-invariant dynamics of different power grids. For a variety of objective functions, a unified framework based on $H_2$ norm is presented to analyze the robustness to ambient fluctuations. Such objectives include loss reduction, weighted consensus of phase angle deviations, oscillations in nodal frequency, and other graphical metrics. The framework is then used to study the problem of optimal topology design for robust control goals of different grids. For radial grids, the problem is shown as equivalent to the hard "optimum communication spanning tree" problem in graph theory and a combinatorial topology construction is presented with bounded approximation gap. Extended to loopy (meshed) grids, a greedy topology design algorithm is discussed. The performance of the topology design algorithms under multiple control objectives are presented on both loopy and radial test grids. Overall, this paper analyzes topology design algorithms on a broad class of control problems in power grid by exploring their combinatorial and graphical properties.Comment: 6 pages, 3 figures, a version of this work will appear in ACC 201

Elevated PAI-1 is associated with poor clinical outcomes in pediatric patients with acute lung injury.

PurposeDeposition of fibrin in the alveolar space is a hallmark of acute lung injury (ALI). Plasminogen activator inhibitor-1 (PAI-1) is an antifibrinolytic agent that is activated during inflammation. Increased plasma and pulmonary edema fluid levels of PAI-1 are associated with increased mortality in adults with ALI. This relationship has not been examined in children. The objective of this study was to test whether increased plasma PAI-1 levels are associated with worse clinical outcomes in pediatric patients with ALI.Design/methodsWe measured plasma PAI-1 levels on the first day of ALI among 94 pediatric patients enrolled in two separate prospective, multicenter investigations and followed them for clinical outcomes. All patients met American European Consensus Conference criteria for ALI.ResultsA total of 94 patients were included. The median age was 3.2 years (range 16 days-18 years), the PaO(2)/F(i)O(2) was 141 +/- 72 (mean +/- SD), and overall mortality was 14/94 (15%). PAI-1 levels were significantly higher in nonsurvivors compared to survivors (P < 0.01). The adjusted odds of mortality doubled for every log increase in the level of plasma PAI-1 after adjustment for age and severity of illness.ConclusionsHigher PAI-1 levels are associated with increased mortality and fewer ventilator-free days among pediatric patients with ALI. These findings suggest that impaired fibrinolysis may play a role in the pathogenesis of ALI in pediatric patients and suggest that PAI-1 may serve as a useful biomarker of prognosis in patients with ALI

The Eternal Unprovability Filter – Part I

I prove both the mathematical conjectures P ≠ NP and the Continuum Hypothesis are eternally unprovable using the same fundamental idea. Starting with the Saunders Maclane idea that a proof is eternal or it is not a proof, I use the indeterminacy of human biological capabilities in the eternal future to show that since both conjectures are independent of Axioms and have definitions connected with human biological capabilities, it would be impossible to prove them eternally without the creation and widespread acceptance of new axioms. I also show that the same fundamental concepts cannot be used to demonstrate the eternal unprovability of many other mathematical theorems and open conjectures. Finally I investigate the idea’s implications for the foundations of mathematics including its relation to Godel’s Incompleteness Theorem and Tarsky’s Undefinability Theorem

Optimal Source Tracking and Beaming of LISA

We revisit the directionally optimal data streams of LISA first introduced in Nayak etal. It was shown that by using appropriate choice of Time delay interferometric (TDI) combinations, a monochromatic fixed source in the barycentric frame can be optimally tracked in the LISA frame. In this work, we study the beaming properties of these optimal streams. We show that all the three streams V+, Vx and Vo with maximum, minimum and zero directional SNR respectively are highly beamed. We study in detail the frequency dependence of the beaming.Comment: 8 pages, 9 figures. To appear in the proceedings of Sixth International LISA Symposiu

Local generation of hydrogen for enhanced photothermal therapy.

By delivering the concept of clean hydrogen energy and green catalysis to the biomedical field, engineering of hydrogen-generating nanomaterials for treatment of major diseases holds great promise. Leveraging virtue of versatile abilities of Pd hydride nanomaterials in high/stable hydrogen storage, self-catalytic hydrogenation, near-infrared (NIR) light absorption and photothermal conversion, here we utilize the cubic PdH0.2 nanocrystals for tumour-targeted and photoacoustic imaging (PAI)-guided hydrogenothermal therapy of cancer. The synthesized PdH0.2 nanocrystals have exhibited high intratumoural accumulation capability, clear NIR-controlled hydrogen release behaviours, NIR-enhanced self-catalysis bio-reductivity, high NIR-photothermal effect and PAI performance. With these unique properties of PdH0.2 nanocrystals, synergetic hydrogenothermal therapy with limited systematic toxicity has been achieved by tumour-targeted delivery and PAI-guided NIR-controlled release of bio-reductive hydrogen as well as generation of heat. This hydrogenothermal approach has presented a cancer-selective strategy for synergistic cancer treatment

Pre-hospital management of acute Addison’s Disease – Audit of patients attending a referral hospital in a regional area

Context: Adrenal crises (AC) cause morbidity and mortality in patients with Addison’s disease [primary adrenal insufficiency (PAI)]. Patient-initiated oral stress dosing, with parenteral hydrocortisone, is recommended to avert ACs. While these should be effective, the continued incidence of ACs remains largely unexplained. Methods: Audit of all attendances between 2000 and 2017 by adult patients with treated PAI to one large regional referral centre in New South Wales, Australia. Measurements were those taken on arrival at hospital. Results: There were 252 attendances by 56 patients with treated PAI during the study period. Women comprised 60.7% (n=34) of the patients. The mean age of attendees was 53.7 (19.6) years. Nearly half (45.2%, n=114) the patients had an infection. There were 61 (24.2%) ACs diagnosed by the treating clinician. Only 17.9% (n=45) of the hospital presentations followed any form of stress dosing. IM hydrocortisone was used before 7 (2.8%) attendances only. Among patients with a clinician diagnosed AC, only 32.8% (n=20) had used stress dosing before presentation. Vomiting was reported by 47.6% (n=120) of the patients but only 33 (27.5%) of these attempted stress dosing and 5 patients with vomiting used IM hydrocortisone. The number of prior presentations was a significant independent predictor of use of stress doses [1.05 (1.01,1.09)]. Conclusion: Dose escalation strategies are not used universally or correctly by unwell patients with PAI, many patients do not use IM or SC hydrocortisone injections. Previous hospital treatment increases the likelihood of stress dosing and offers the opportunity for reinforcement of prevention strategies