Efficiency of energy transfer, but not external work, is maximized in stunned myocardium

There is no evidence regarding the effect of stunning on maximization of regional myocardial external work (EW) or efficiency of energy transfer (EET) in relation to regional afterload (end-systolic stress, sigma(es)). To that end, we studied these relationships in both the left anterior descending coronary artery (LADCA) and left circumflex coronary artery regions in anesthetized, open-chest pigs before and after LADCA stunning. In normal myocardium, EET vs. sigma(es) was maximal at 75.4 (69.7-81.0)%, whereas EW vs. sigma(es) was submaximal at 12.0 (6.61-17.3) x 10(2) J/m(3). Increasing sigma(es) increased EW by 18 (10-27)%. Regional myocardial stunning decreased EET (27%) and EW (36%) and caused the myocardium to operate both at maximal EW (EW(max)) and at maximal EET (EET(max)). EET and EW became also more sensitive to changes in sigma(es). In the nonstunned region the situation remained unchanged. Combining the data from before and after stunning, both EW(max) and EET(max) displayed a positive relationship with contractility. In conclusion, the normal regional myocardium operated at maximal EET rather than at maximal EW. Therefore, additional EW could be recruited by increasing regional afterload. After myocardial stunning, the myocardium operated at both maximal EW and maximal EET, at the cost of increased afterload sensitivity. Contractility was a major determinant of this shift

Solving the Klein-Gordon equation using Fourier spectral methods: A benchmark test for computer performance

The cubic Klein-Gordon equation is a simple but non-trivial partial differential equation whose numerical solution has the main building blocks required for the solution of many other partial differential equations. In this study, the library 2DECOMP&FFT is used in a Fourier spectral scheme to solve the Klein-Gordon equation and strong scaling of the code is examined on thirteen different machines for a problem size of 512^3. The results are useful in assessing likely performance of other parallel fast Fourier transform based programs for solving partial differential equations. The problem is chosen to be large enough to solve on a workstation, yet also of interest to solve quickly on a supercomputer, in particular for parametric studies. Unlike other high performance computing benchmarks, for this problem size, the time to solution will not be improved by simply building a bigger supercomputer.Comment: 10 page

A United States Air Force Site Selection Methodology in a Contested Agile Combat Employment Environment

The United States Air Force’s (USAF) Agile Combat Employment (ACE) strategy relies on host country access and underlying local infrastructure to facilitate airpower. However, numerous factors, including peer-to-peer threats, complex geopolitics, and intricate supply chain management, often complicate site access and thwart site selection decisions. When shaping the battlespace for future conflict, strategists and planners face the difficult task of identifying optimal locations to conduct adaptive basing operations given these complicating factors. Multi-Criteria Decision Analysis (MCDA) can help strategists appropriately account for competing objectives and maintain a competitive advantage with theater adversaries. This thesis presents an MCDA model that evaluates ACE site selection alternatives within the Pacific Air Forces (PACAF) Area of Responsibility (AOR) using a geographic information system (GIS) enabled analytic hierarchy process (AHP) methodology and open-source data pertinent to the theater. The model analyzed 576 airports in 26 countries and compared alternative locations based on runway length, the Fragile States Index (FSI), the population center of the People’s Republic of China, construction equipment dealers, and natural water resources. The results demonstrate the framework’s efficacy and utility in identifying existing airports best suited for the deployment of USAF combat and support assets. The methodology is expected to provide invaluable support to Combatant Commanders as they optimize ACE infrastructure, preserve resources, and minimize risk to United States Armed Forces

Atheïstische religiositeit

AtheismAtheïsme en religiositeit lijken elkaars absolute tegenpolen. Filosoof Wim Van Moer stelt deze intuïtieve, ook onder atheïsten wijdverspreide overtuiging ter discussie. Deze analyse onthult dat de religieuze ervaring niet verbonden hoeft te zijn met een geloof in een bovennatuurlijke entiteit of realiteit. Geïnspireerd door Leo Apostel en in de voetsporen van William James en Erich Fromm, betoogt de auteur dat deze tegenstrijdigheid, zelfs binnen een radicaal atheïstisch vertoog, niet automatisch geldig is. Van Moer staaft deze stelling met een meeslepende fenomenologische analyse van de religieuze ervaring, die uitmondt in een theoretisch model waarmee hij religieuze ervaringen binnen een atheïstische context kan onderzoeken

Pairwise forward trading and bilateral oligopoly

This paper investigates pairwise efficient forward trading followed by spot market competition. The model finds that forward trading rules out a “bilateral oligopoly” spot market where at least one net seller under-supplies and least one net buyer under-procures. If not, both firms, by exercising market power, would hurt each other, a negative externality problem which can be mitigated by pairwise forward trading. Next, a configuration is analyzed where firms’ marginal costs increase linearly with slopes inversely related to their capacities. It is shown that assuming market shares equal capacity shares overstates the Hirschman-Herfindahl Index, a result useful for merger evaluation

Horizontal agreements about the use of a natural resource

I study a class of agreements between product market rivals to restrict their usage of a natural resource. The natural resource serves as an input for production and can imperfectly be replaced by a basket of other resources. The class of permissible agreements includes various quantitative and pricing instruments that fall short of pure price fixing. Under baseline conditions, namely that firms and consumers do not take into account external effects, I characterize the types of restrictions that succeed in breaking the status quo and the types that do not. Agreements that break the status quo reduce the usage of the natural resource but induce firms to set higher prices in the product market. The effect on prices is what motivates firms to make the agreement. Firms prefer the type of restriction that requires as little reduction in usage of the natural resource as possible in order to induce a given price increase. Implications for competition policy are discussed