Three--dimensional medical imaging: Algorithms and computer systems

This paper presents an introduction to the field of three-dimensional medical imaging It presents medical imaging terms and concepts, summarizes the basic operations performed in three-dimensional medical imaging, and describes sample algorithms for accomplishing these operations. The paper contains a synopsis of the architectures and algorithms used in eight machines to render three-dimensional medical images, with particular emphasis paid to their distinctive contributions. It compares the performance of the machines along several dimensions, including image resolution, elapsed time to form an image, imaging algorithms used in the machine, and the degree of parallelism used in the architecture. The paper concludes with general trends for future developments in this field and references on three-dimensional medical imaging

“They” are old but “I” feel younger: Age-group dissociation as a self-protective strategy in old age

Age becomes an important self-defining aspect particularly during advanced age. With increasing age, negative attributes related to age and aging become salient. Aging-related declines, losses, as well as the finitude of life seem to threaten older adults' sense of self. We hypothesize that older adults will try to avoid the negative consequences of their age group membership by distancing themselves from their age group. Study 1 (N = 544, 65% women; 18–85 years of age) examined the role of age-group identification for self-conception and self-image (subjective age and future time perspective) across the life span. Results show that weakly identified older adults feel younger than their chronological age and report a more expanded future time perspective relative to their same-age counterparts. A second experiment (N = 68, 69% women; 65–85 years of age) tested the impact of age stereotypes on older adults' level of age-group identification. Results suggest that older adults are more likely to psychologically dissociate themselves from their age group when negative age stereotypes are salient. Discussion focuses on (mal)adaptive consequences of age-group dissociation in later adulthood

Precise determination of the sigma pole location from a dispersive analysis

We review how the use of recent precise data on kaon decays together with forward dispersion relations (FDR) and Roy's equations allow us to determine the sigma resonance pole position very precisely, by using only experimental input. In addition, we present preliminary results for a modified set of Roy-like equations with only one subtraction, that show a remarkable improvement in the precision around the sigma resonance region. For practical applications, these results are shown to be very well approximated by a very simple conformal expansion.Comment: 5 pages, 2 figures. To appear in the proceedings of the Workshop on Scalar Mesons and Related Topics, Lisbon, Portugal, 11-16 Feb 200

NASTRAN Modeling of Flight Test Components for UH-60A Airloads Program Test Configuration

Based upon the recommendations of the UH-60A Airloads Program Review Committee, work towards a NASTRAN remodeling effort has been conducted. This effort modeled and added the necessary structural/mass components to the existing UH-60A baseline NASTRAN model to reflect the addition of flight test components currently in place on the UH-60A Airloads Program Test Configuration used in NASA-Ames Research Center's Modern Technology Rotor Airloads Program. These components include necessary flight hardware such as instrument booms, movable ballast cart, equipment mounting racks, etc. Recent modeling revisions have also been included in the analyses to reflect the inclusion of new and updated primary and secondary structural components (i.e., tail rotor shaft service cover, tail rotor pylon) and improvements to the existing finite element mesh (i.e., revisions of material property estimates). Mode frequency and shape results have shown that components such as the Trimmable Ballast System baseplate and its respective payload ballast have caused a significant frequency change in a limited number of modes while only small percent changes in mode frequency are brought about with the addition of the other MTRAP flight components. With the addition of the MTRAP flight components, update of the primary and secondary structural model, and imposition of the final MTRAP weight distribution, modal results are computed representative of the 'best' model presently available

Precise analysis of pion-pion scattering data from Roy equations and forward dispersion relations

We review our recent analysis of pion-pion scattering data in terms of Roy equations and Forward Dispersion Relations, and present some preliminary results in terms of a new set of once-subtracted coupled equations for partial waves. The first analysis consists of independent fits to the different pion-pion channels that satisfies rather well the dispersive representation. In the second analysis we constrain the fit with the dispersion relations. The latter provides a very precise and model independent description of data using just analyticity, causality and crossing.Comment: 6 pages, two figures. To appear in the proceedings of the Workshop on Scalar Mesons and Related Topics, Lisbon, Portugal, 11-16 Feb 200

Patientenverfügungen in Deutschland: empirische Evidenz für die Jahre 2005 bis 2007

Informationen zur Verbreitung von Patientenverfügungen in der Gesamtbevölkerung beruhen in Deutschland meist auf nicht-repräsentativen kleinen klinischen Stichproben und anekdotischer Evidenz. Aus wissenschaftlicher Sicht sind repräsentative Untersuchungen bedeutsam, die es neben der Deskription erlauben die Bedingungen zu untersuchen, unter denen Menschen, noch ehe sie persönlich betroffen sind, also im präklinischen Kontext, bereit sind - oder aber für sich selbst ablehnen - eine Patientenverfügung zu hinterlegen. In vier Erhebungen ergeben sich ähnliche Größenordnungen von rund 10 % (Bereich: 7-14%) der Erwachsenen, die eine Patientenverfügung hinterlegt haben. Die aktuellste Erhebung ist eine Sondererhebung der Längsschnittstudie "Sozio-oekonomisches Panel" (SOEP) bei 1000 Erwachsenen im Jahr 2007. Danach hat nur jeder zehnte Erwachsene eine Patientenverfügung erstellt. Kompatibel damit ist der Anteil von 7 %, der in dieser Erhebung für nahe stehende Verstorbene angegeben wird. In einer SOEP Sondererhebung im Sommer 2006 gaben etwa 11 % von 400 Befragten an, eine Patientenverfügung erstellt zu haben. In einer Umfrage der Infratest-Finanzforschung im Auftrag der Deutschen Hospizstiftung gaben dies Ende 2005 14 % an. Wir erläutern, warum dieser Wert vermutlich eine Überschätzung darstellt. Weitere Analysen zeigen die sozialen, biografischen und bildungsbezogenen Bedingungen, die zwischen den Menschen differenzieren, die eine Patientenverfügung erstellt haben oder aber für sich explizit ablehnen, eine Patientenverfügung zu erstellen. Die Befunde zeigen, dass neben dem Alter und schlechterem Gesundheitsstatus vor allem die persönliche Erfahrungen mit dem Tod von Angehörige begünstigt, dass eine Patientenverfügungen erstelltund hinterlegt wurde.

D^+ \to K^- \p^+ \p^+ : the low-energy sector

An effective $SU(3)\times SU(3)$ chiral lagrangian, which includes scalar resonances, is used to describe the process D^+ \rar K^- \p^+ \p^+ at low-energies. Our main result is a set of five $S$-wave amplitudes, suited to be used in analyses of production data.Comment: Talk given at SCADRON 70 - Workshop on Scalar Mesons and Related Topics - Lisbon - February 200

Erfassung kognitiver Leistungspotentiale Erwachsener im Sozio-oekonomischen Panel (SOEP)

Im Erhebungsjahr 2006 wurden erstmals in einer Teilstichprobe des SOEP kognitive Kurztests durchgeführt. Ziel war es, ein robustes, von geschulten Interviewern leicht zu administrierendes Instrumentarium einzusetzen, das innerhalb weniger Minuten durchführbar ist. Annähernd 80 % aller zur Durchführung des Kognitionstests ausgewählten Befragungspersonen haben gültige Angeben gemacht. Somit stehen für mehr als 5.500 Personen erstmals neben vielfältigen zertifikatsbasierten Bildungsinformationen auch Indikatoren für kognitive Potentiale zur Verfügung. Neben der Dokumentation der Daten werden in diesem Bericht erste Verteilungen der Maße vorgestellt und Selektionsanalysen präsentiert. Die erste Wiederholungsmessung der Tests ist für das Erhebungsjahr 2010 vorgesehen

Novel population pharmacokinetic approach to explain the differences between cystic fibrosis patients and healthy volunteers via protein binding

The pharmacokinetics in patients with cystic fibrosis (CF) has long been thought to differ considerably from that in healthy volunteers. For highly protein bound beta -lactams, profound pharmacokinetic differences were observed between comparatively morbid patients with CF and healthy volunteers. These differences could be explained by body weight and body composition for beta -lactams with low protein binding. This study aimed to develop a novel population modeling approach to describe the pharmacokinetic differences between both subject groups by estimating protein binding. Eight patients with CF (lean body mass [LBM]: 39.8 +/- 5.4kg) and six healthy volunteers (LBM: 53.1 +/- 9.5kg) received 1027.5 mg cefotiam intravenously. Plasma concentrations and amounts in urine were simultaneously modelled. Unscaled total clearance and volume of distribution were 3% smaller in patients with CF compared to those in healthy volunteers. After allometric scaling by LBM to account for body size and composition, the remaining pharmacokinetic differences were explained by estimating the unbound fraction of cefotiam in plasma. The latter was fixed to 50% in male and estimated as 54.5% in female healthy volunteers as well as 56.3% in male and 74.4% in female patients with CF. This novel approach holds promise for characterizing the pharmacokinetics in special patient populations with altered protein binding