A classical two-body Hamiltonian model and its mean field approximation

We extend a recent billiard model of the nuclear N-body Hamiltonian to consider a finite two-body interaction. This permits a treatment of the Hamiltonian by a mean field theory, and also allows the possibility to model reactions between nuclei. The density and the mean field potential can be accurately described by a scaling function which shows the qualitative features of the liquid drop picture of the nucleus.Comment: 9 pages, 2 PS-figures, uses psfig.st

Pancreatic phospholipase A2 activity in acute pancreatitis: A prognostic marker for early identification of patients at risk

Remarkably elevated levels of phospholipase A(2) (PLA(2)) are measurable in human blood samples in cases of acute pancreatitis. The source of the enzyme was first thought to be exclusively the pancreas, but now it is generally accepted that two isoenzymes the pancreatic PLA(2), group I, and the extrapancreatic PLA(2), group II contribute to the raised activity. In contrast to the group II-PLA(2), the pancreatic PLA(2) is heatresistant for 1 hour at 60 degreesC. The catalytically inactive proenzyme of the pancreatic PLA(2) can be activated by trypsin. The aim of our study was to evaluate the diagnostic value of PLA(2) isoenzyme activity measurements to identify patients with severe complications in acute pancreatitis. Blood samples from patients suffering from acute pancreatitis were analyzed for catalytically active pancreatic PLA(2) on day 1 and 2 of hospitalization with a modified radiometric Escherichia colibased PLA(2) assay. In 10 of 41 patients clearly elevated values of catalytically active, heatresistant pancreatic PLA(2) (7.2 to 81.2 U/l) were observed. This group of patients was characterized by severe complications (necrotizing pancreatitis, shock, sepsis, respiratory problems) of which two patients subsequently died. Patients with low or undetectable activity (<7 U/l) of pancreatic PLA(2) recovered rapidly. According to these results the presence of catalytically active pancreatic PLA(2) in serum is associated with severe complications of acute pancreatitis. In contrast to total serumPLA(2), the catalytic concentration of pancreatic PLA(2) can serve as a prognostic marker in acute pancreatitis

Drivers of people's preferences for spatial proximity to energy infrastructure technologies: a cross-country analysis. ESRI WP583, February 2018

Many countries plan to decarbonise their energy systems by increasing energy efficiency and expanding the use of renewable energy sources (RES). Such actions require significant investments in new energy infrastructures. While people are generally accepting of these infrastructures, opposition sometimes arises when these developments are sited at close proximity to people's residences. Therefore, it is important to understand what actually drives people's preferences for spatial proximity to different energy infrastructure technologies. This study examines the factors influencing people's proximity preferences to different energy technologies using a cross-country econometric analysis of the stated preference data from an unprecedented survey conducted on nationally representative samples of the population in Ireland, the US and Germany. The survey involved more than 4,500 participants in total. This paper presents the data and selected results from a generalised ordered logit model for each energy technology surveyed. These are; wind turbines, solar power technology, biomass power plant, coal-red power plant and natural gas power plant. The results show that, in general, German and Irish citizens are willing to accept energy infrastructures at smaller distances to their homes than their US counterparts. Moreover, attitudinal factors are found to shape people's preferences more consistently than any of the socio-demographic characteristics

Homocysteine in cerebrovascular disease: An independent risk factor for subcortical vascular encephalopathy

Hyperhomocysteinemia is a risk factor for obstructive large-vessel disease. Here, we studied plasma concentrations of homocysteine and vitamins in patients suffering from subcortical vascular encephalopathy (SVE), a cerebral small-vessel disease leading to dementia. These results were compared to the homocysteine and vitamin plasma concentrations from patients with cerebral large vessel disease and healthy control subjects. Plasma concentrations of homocysteine, vascular risk factors and vitamin status (B-6, B-12, folate) were determined in 82 patients with subcortical vascular encephalopathy, in 144 patients with cerebral large-vessel disease and in 102 control subjects. Patients with SVE, but not those with cerebral large-vessel disease, exhibited pathologically increased homocysteine concentrations in comparison with control subjects without cerebrovascular disease. Patients with SVE also showed lower vitamin B6 values in comparison to subjects without cerebrovascular disease. Logistic regression analysis showed that homocysteine is associated with the highest risk for SVE (odds ratio 5.7; CI 2.5-12.9) in comparison to other vascular risk factors such as hypertension, age and smoking. These observations indicate that hyperhomocysteinemia is a strong independent risk factor for SVE

Numeric and symbolic evaluation of the pfaffian of general skew-symmetric matrices

Evaluation of pfaffians arises in a number of physics applications, and for some of them a direct method is preferable to using the determinantal formula. We discuss two methods for the numerical evaluation of pfaffians. The first is tridiagonalization based on Householder transformations. The main advantage of this method is its numerical stability that makes unnecessary the implementation of a pivoting strategy. The second method considered is based on Aitken's block diagonalization formula. It yields to a kind of LU (similar to Cholesky's factorization) decomposition (under congruence) of arbitrary skew-symmetric matrices that is well suited both for the numeric and symbolic evaluations of the pfaffian. Fortran subroutines (FORTRAN 77 and 90) implementing both methods are given. We also provide simple implementations in Python and Mathematica for purpose of testing, or for exploratory studies of methods that make use of pfaffians.Comment: 13 pages, Download links: http://gamma.ft.uam.es/robledo/Downloads.html and http://www.phys.washington.edu/users/bertsch/computer.htm

High-sensitivity troponin assays in the evaluation of patients with acute chest pain in the emergency department

Evaluating patients with acute chest pain presenting to the emergency department remains an ongoing challenge. The spectrum of etiologies in acute chest pain ranges from minor disease entities to life-threatening diseases, such as pulmonary embolism, acute aortic dissection or acute myocardial infarction (MI). The diagnosis of acute MI is usually made integrating the triad of patient history and clinical presentation, readings of 12-lead ECG and measurement of cardiac troponins (cTn). Introduction of high-sensitivity cTn assays substantially increases sensitivity to identify patients with acute MI even at the time of presentation to the emergency department at the cost of specificity. However, the proportion of patients presenting with cTn positive, non-vascular cardiac chest pain triples with the implementation of new sensitive cTn assays increasing the difficulty for the emergency physician to identify those patients who are at need for invasive diagnostics. The main objectives of this mini-review are 1) to discuss elements of disposition decision made by the emergency physician for the evaluation of chest pain patients, 2) to summarize recent advances in assay technology and relate these findings into the clinical context, and 3) to discuss possible consequences for the clinical work and suggest an algorithm for the clinical evaluation of chest pain patients in the emergency departmen