PCA-based lung motion model

Organ motion induced by respiration may cause clinically significant targeting errors and greatly degrade the effectiveness of conformal radiotherapy. It is therefore crucial to be able to model respiratory motion accurately. A recently proposed lung motion model based on principal component analysis (PCA) has been shown to be promising on a few patients. However, there is still a need to understand the underlying reason why it works. In this paper, we present a much deeper and detailed analysis of the PCA-based lung motion model. We provide the theoretical justification of the effectiveness of PCA in modeling lung motion. We also prove that under certain conditions, the PCA motion model is equivalent to 5D motion model, which is based on physiology and anatomy of the lung. The modeling power of PCA model was tested on clinical data and the average 3D error was found to be below 1 mm.Comment: 4 pages, 1 figure. submitted to International Conference on the use of Computers in Radiation Therapy 201

A COMPARISON BETWEEN 1.5µm PHOTOLUMINESCENCE FROM Er-DOPED Si-RICH SiO2 FILMS AND (Er,Ge) CO-DOPED SiO2 FILMS

photoluminescence, nanoclusters, erbium, Transmission electron microscopyWe have studied the 1.5 µm photoluminescence (PL) from Er ions after annealing two different sample sets in the temperature range 500 °C to 1100 °C. The different sample sets were made by magnetron sputtering from composite targets of Si+SiO2+Er and Ge+SiO2+Er respectively for the different sample sets. The annealing induces Si - and Ge-nanoclusters respectively in the different film sets. The PL peak reaches its maximum intensity after annealing at 700 °C for samples with Ge nanoclusters and after annealing at 800 °C for samples with Si. No luminescence from nanoclusters was detected in neither sample sets. This is interpreted as an energy transfer from the nanocluster to Er atoms. Transmission electron microscopy shows that after annealing to the respective temperature yielding the maximum PL intensity both the Ge and Si clusters are non-crystalline. Here we mainly compare the spectral shape of Er luminescence emitted in these different nanostructured matrixes. The PL spectral shapes are clearly different and witness a different local environment for the Er ions

Evaluating the Impacts of Subsidies on Innovation Activities in Germany

Innovations are a key factor to ensure the competitiveness of establishments as well as to enhance the growth and wealth of nations. But more than any other economic activity, decisions about innovations are plagued by failures of the market mechanism. As a response, public instruments have been implemented to stimulate private innovation activities. The effectiveness of these measures, however, is ambiguous and calls for an empirical evaluation. In this paper we make use of the IAB Establishment Panel and apply various microeconometric methods to estimate the effect of public measures on innovation activities of German establishments. We find that neglecting sample selection due to observable as well as to unobservable characteristics leads to an overestimation of the treatment effect and that there are considerable differences with regard to size class and betweenWest and East German establishments

Theory and practice in Finnish teacher education : a rhetorical analysis of changing values from the 1960s to the present day

Our aim in this article is to examine the relationship between theory and practice in Finnish teacher education from the 1960s to the present. We identify four different periods to represent this relationship based on our analysis of national committee and evaluation reports. Theory and practice gradually converged, culminating in a research-based agenda that reflects the current situation. This relationship between theory and practice also reflects the ideal teacher of different times and what a teacher's working orientation should be. We use rhetorical analysis and the concept of a 'philosophical pair' introduced by Perelman and Olbrechts-Tyteca to interpret this development.Peer reviewe

Digital image analysis of fingernail colour in cadavers comparing carbon monoxide poisoning to controls

The original publication is available at www.springerlink.comCarbon monoxide is a component of motor vehicle exhaust fumes, provided a functional catalytic converter is not present. This gas binds avidly to the hemoglobin molecule in red blood cells preventing its oxygen transport function, effectively poisoning the body by starving it of oxygen. In binding to hemoglobin, carbon monoxide forms carboxyhemoglobin, which has a characteristic bright pink color. It has been remarked that the fingernails of victims of carbon monoxide tend to exhibit pink color, otherwise fingernails of deceased bodies tend towards a dark red to blue color. This study sought to objectively determine by using digital image analysis if a color difference occurred between the fingernails of a group of cadavers with carbon monoxide poisoning compared to a group of controls. The fingernails of the carbon monoxide group did tend to be more red than the controls, but due to overlap between the two groups assessment of the fingernails cannot be recommended as a rapid screening test.Neil E. I. Langloi