28 resultados para real von Neumann measurement
Resumo:
In der vorliegenden Arbeit werden Entwicklung und Validierung eines Fragebogens zur umfassenden Erfassung der Achtsamkeit, des Comprehensive Inventory of Mindfulness Experiences (CHIME), beschrieben. An einer Allgemeinbevölkerungs-Stichprobe (N = 298) und einer Stichprobe von TeilnehmerInnen an MBSR-Kursen (N = 161) wurde die Faktorenstruktur des CHIME ermittelt und seine Reliabilität und Validität geprüft. Faktorenanalytische Verfahren ergaben eine achtfaktorielle Struktur. Die Struktur wurde in einer zusätzlichen konfirmatorischen Stichprobe (N = 202) überprüft. Der Fragebogen sowie seine Unterskalen weisen gute Reliabilitätswerte auf (interne Konsistenz und Retest-Reliabilität). Analysen zur Messinvarianz der einzelnen Items über Gruppen, die sich bezüglich Meditationserfahrung, Alter, Geschlecht und Symptombelastung unterschieden, zeigten keine systematischen Unterschiede im Verständnis der Items. Die Kennwerte zur Konstrukt-, Kriterium-, und inkrementellen Validität sowie zur Veränderungssensitivität waren alle mindestens zufriedenstellend. Mit dem CHIME steht somit ein Fragebogen mit guten psychometrischen Eigenschaften zur Selbsteinschätzung der Achtsamkeit zur Verfügung. Der CHIME basiert auf allen in den aktuellen Instrumenten enthaltenen Aspekten des Achtsamkeitskonstrukts.
Resumo:
BACKGROUND The majority of radiological reports are lacking a standard structure. Even within a specialized area of radiology, each report has its individual structure with regards to details and order, often containing too much of non-relevant information the referring physician is not interested in. For gathering relevant clinical key parameters in an efficient way or to support long-term therapy monitoring, structured reporting might be advantageous. OBJECTIVE Despite of new technologies in medical information systems, medical reporting is still not dynamic. To improve the quality of communication in radiology reports, a new structured reporting system was developed for abdominal aortic aneurysms (AAA), intended to enhance professional communication by providing the pertinent clinical information in a predefined standard. METHODS Actual state analysis was performed within the departments of radiology and vascular surgery by developing a Technology Acceptance Model. The SWOT (strengths, weaknesses, opportunities, and threats) analysis focused on optimization of the radiology reporting of patients with AAA. Definition of clinical parameters was achieved by interviewing experienced clinicians in radiology and vascular surgery. For evaluation, a focus group (4 radiologists) looked at the reports of 16 patients. The usability and reliability of the method was validated in a real-world test environment in the field of radiology. RESULTS A Web-based application for radiological "structured reporting" (SR) was successfully standardized for AAA. Its organization comprises three main categories: characteristics of pathology and adjacent anatomy, measurements, and additional findings. Using different graphical widgets (eg, drop-down menus) in each category facilitate predefined data entries. Measurement parameters shown in a diagram can be defined for clinical monitoring and be adducted for quick adjudications. Figures for optional use to guide and standardize the reporting are embedded. Analysis of variance shows decreased average time required with SR to obtain a radiological report compared to free-text reporting (P=.0001). Questionnaire responses confirm a high acceptance rate by the user. CONCLUSIONS The new SR system may support efficient radiological reporting for initial diagnosis and follow-up for AAA. Perceived advantages of our SR platform are ease of use, which may lead to more accurate decision support. The new system is open to communicate not only with clinical partners but also with Radiology Information and Hospital Information Systems.
Resumo:
Accurate measurement of abdominal aortic aneurysms is necessary to predict rupture risk and, more recently, to follow aneurysm sac behavior following endovascular repair. Up until this point, aneurysm diameter has been the most common measurement utilized for these purposes. Although aneurysm diameter is predictive of rupture, accurate measurement is hindered by such factors as aortic tortuosity and interobserver variability, and it does not account for variations in morphology such as saccular aneurysms. Additionally, decreases in aneurysm diameter do not completely describe the somewhat complex remodeling seen following endovascular repair of aortic aneurysms. Measurement of aneurysm volume has the advantage of describing aneurysm morphology in a multidimensional fashion, but it has not been readily available or easily measured until recently. This has changed with the introduction of commercially available software tools that permit quicker and easier to perform volume measurements. Whether it is time for volume to replace, or compliment, diameter is the subject of the current debate.
Resumo:
We consider a large quantum system with spins 12 whose dynamics is driven entirely by measurements of the total spin of spin pairs. This gives rise to a dissipative coupling to the environment. When one averages over the measurement results, the corresponding real-time path integral does not suffer from a sign problem. Using an efficient cluster algorithm, we study the real-time evolution from an initial antiferromagnetic state of the two-dimensional Heisenberg model, which is driven to a disordered phase, not by a Hamiltonian, but by sporadic measurements or by continuous Lindblad evolution.
Resumo:
In Untersuchungen zum Umweltbewusstsein und Umweltverhalten werden die zentralen Variablen in der Regel auf der Basis von Selbstauskünften und mittels Itembatterien erhoben. Fraglich ist dabei, ob die Items zur Messung ökologischen Handelns mehr als nur \"symbolisches Verhalten\" erfassen. Bodenstein, Spiller und Elbers (1997) haben kürzlich einen Index vorgeschlagen, der sich am tatsächlichen Energie- und Materialverbrauch eines Haushalts orientiert. Wir vergleichen dieses Konzept mit anderen Skalen und untersuchen empirisch anhand der Daten des Surveys \"Umweltbewusstsein in Deutschland 1998\", in welchem Ausmaß die Ergebnisse von Regressionsmodellen des Umwelthandelns von den jeweils zugrunde gelegten Skalen abhängen. Es zeigt sich, dass gerade bezüglich der zentralen Determinanten \"Umweltbewusstsein\" und \"Einkommen\" beträchtliche Unterschiede bestehen.
Resumo:
ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift field generated in-situ by a Greinacher voltage multiplier circuit. We present results on the measurement of the drift-field distribution inside ARGONTUBE using straight ionization tracks generated by an intense UV laser beam. Our analysis is based on a simplified model of the charging of a multi-stage Greinacher circuit to describe the voltages on the field cage rings.
Resumo:
A detailed characterization of air quality in the megacity of Paris (France) during two 1-month intensive campaigns and from additional 1-year observations revealed that about 70% of the urban background fine particulate matter (PM) is transported on average into the megacity from upwind regions. This dominant influence of regional sources was confirmed by in situ measurements during short intensive and longer-term campaigns, aerosol optical depth (AOD) measurements from ENVISAT, and modeling results from PMCAMx and CHIMERE chemistry transport models. While advection of sulfate is well documented for other megacities, there was surprisingly high contribution from long-range transport for both nitrate and organic aerosol. The origin of organic PM was investigated by comprehensive analysis of aerosol mass spectrometer (AMS), radiocarbon and tracer measurements during two intensive campaigns. Primary fossil fuel combustion emissions constituted less than 20%in winter and 40%in summer of carbonaceous fine PM, unexpectedly small for a megacity. Cooking activities and, during winter, residential wood burning are the major primary organic PM sources. This analysis suggests that the major part of secondary organic aerosol is of modern origin, i.e., from biogenic precursors and from wood burning. Black carbon concentrations are on the lower end of values encountered in megacities worldwide, but still represent an issue for air quality. These comparatively low air pollution levels are due to a combination of low emissions per inhabitant, flat terrain, and a meteorology that is in general not conducive to local pollution build-up. This revised picture of a megacity only being partially responsible for its own average and peak PM levels has important implications for air pollution regulation policies.
Resumo:
A fast and automatic method for radiocarbon analysis of aerosol samples is presented. This type of analysis requires high number of sample measurements of low carbon masses, but accepts precisions lower than for carbon dating analysis. The method is based on online Trapping CO2 and coupling an elemental analyzer with a MICADAS AMS by means of a gas interface. It gives similar results to a previously validated reference method for the same set of samples. This method is fast and automatic and typically provides uncertainties of 1.5–5% for representative aerosol samples. It proves to be robust and reliable and allows for overnight and unattended measurements. A constant and cross contamination correction is included, which indicates a constant contamination of 1.4 ± 0.2 μg C with 70 ± 7 pMC and a cross contamination of (0.2 ± 0.1)% from the previous sample. A Real-time online coupling version of the method was also investigated. It shows promising results for standard materials with slightly higher uncertainties than the Trapping online approach.
Resumo:
Einstellungen und Emotionen im Kontext der Schule spielen für das Lernen eine zentrale Rolle. Dennoch gibt es bisher eher wenige empirische Studien zu Wahrnehmungen und Bewertungen von Grundschulkindern. Insbesondere fehlen domänenspezifische Zügänge, d. h. Untersuchungen, in denen die Einstellungen der Kinder gegenüber einem bestimmten Fach analysiert werden. Im Zuge unserer Studie wurde versucht, die Einstellungen von N=165 österreichischen Grundschulkindern der Schulstufen 1-4 zum Fach Mathematik über ein Schuljahr hinweg und bis zu Beginn der nachfolgenden Schulstufen nachzuzeichnen und Veränderungen aufzuzeigen (vier Messzeitpunkte). Die Kinder wurden dabei zu ihren Fachpräferenzen in der Schule und zu ihren Bewertungen des Fachs Mathematik schriftlich befragt. Als Referenzfach diente das Fach Zeichnen, um die Ergebnisse zum Mathematikunterricht besser einzuschätzen zu können. Die Einstellungen gegenüber dem Mathematikunterricht wurden zudem mit Leistungen der Kinder (Mathematikzeugnisnoten und Rechentest) in Beziehung gesetzt. Die Ergebnisse verdeutlichen überwiegend positive Einstellungen zum Fach Mathematik, verweisen aber auch auf deren Rückgang im Verlauf des Schuljahrs, der sich weitgehend unabhängig vom Geschlecht und der Leistungen der Kinder vollzieht.
Resumo:
In situ and simultaneous measurement of the three most abundant isotopologues of methane using mid-infrared laser absorption spectroscopy is demonstrated. A field-deployable, autonomous platform is realized by coupling a compact quantum cascade laser absorption spectrometer (QCLAS) to a preconcentration unit, called trace gas extractor (TREX). This unit enhances CH4 mole fractions by a factor of up to 500 above ambient levels and quantitatively separates interfering trace gases such as N2O and CO2. The analytical precision of the QCLAS isotope measurement on the preconcentrated (750 ppm, parts-per-million, µmole mole−1) methane is 0.1 and 0.5 ‰ for δ13C- and δD-CH4 at 10 min averaging time. Based on repeated measurements of compressed air during a 2-week intercomparison campaign, the repeatability of the TREX–QCLAS was determined to be 0.19 and 1.9 ‰ for δ13C and δD-CH4, respectively. In this intercomparison campaign the new in situ technique is compared to isotope-ratio mass spectrometry (IRMS) based on glass flask and bag sampling and real time CH4 isotope analysis by two commercially available laser spectrometers. Both laser-based analyzers were limited to methane mole fraction and δ13C-CH4 analysis, and only one of them, a cavity ring down spectrometer, was capable to deliver meaningful data for the isotopic composition. After correcting for scale offsets, the average difference between TREX–QCLAS data and bag/flask sampling–IRMS values are within the extended WMO compatibility goals of 0.2 and 5 ‰ for δ13C- and δD-CH4, respectively. This also displays the potential to improve the interlaboratory compatibility based on the analysis of a reference air sample with accurately determined isotopic composition.
Resumo:
Measuring the ratio of heterophils and lymphocytes (H/L) in response to different stressors is a standard tool for assessing long-term stress in laying hens but detailed information on the reliability of measurements, measurement techniques and methods, and absolute cell counts is often lacking. Laying hens offered different sites of the nest boxes at different ages were compared in a two-treatment crossover experiment to provide detailed information on the procedure for measuring and the difficulties in the interpretation of H/L ratios in commercial conditions. H/L ratios were pen-specific and depended on the age and aviary system. There was no effect for the position of the nest. Heterophiles and lymphocytes were not correlated within individuals. Absolute cell counts differed in the number of heterophiles and lymphocytes and H/L ratios, whereas absolute leucocyte counts between individuals were similar. The reliability of the method using relative cell counts was good, yielding a correlation coefficient between double counts of r > 0.9. It was concluded that population-based reference values may not be sensitive enough to detect individual stress reactions and that the H/L ratio as an indicator of stress under commercial conditions may not be useful because of confounding factors and that other, non-invasive, measurements should be adopted.