Longitudinal validity of spirometers--a challenge in longitudinal studies.

Pulmonary function testing (PFT) in longitudinal studies involves the repeated use of spirometers over long time periods. We assess the comparability of PFT results taken under biologic field conditions using thirteen certified devices of various technology and age. Comparability of measurements across devices and over time is relevant both in clinical and epidemiological research. Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1) and Forced Expiratory Flow 50% (FEF50) were compared before and after the data collection of the Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) and the European Community Respiratory Health Survey (ECRHS) cohort studies. Three test series were conducted with 46, 50 and 56 volunteers using various combinations of spirometers to compare the eight flow-sensing spirometers (Sensormedics 2200) used in the SAPALDIA cross-sectional and follow-up, two new flow-sensing instruments (Sensormedics Vmax) and three volume displacement spirometers (two Biomedin/Baires and one Sensormedics 2400). The initial comparison (1999/2000) of eight Sensormedics 2200 and the follow-up comparison (2003) of the same devices revealed a maximal variation of up to 2.6% for FVC, 2.4% for FEV1 and 2.8% for FEF50 across devices with no indication of systematic differences between spirometers. Results were also reproducible between Biomedin, Sensormedics 2200 and 2400. The new generation of Sensormedics (Vmax) gave systematically lower results. The study demonstrates the need to conduct spirometer comparison tests with humans. For follow-up studies we strongly recommend the use of the same spirometers

The composite picture of the charge carriers in La2-xSrxCuO4 (0.063 < x < 0.11) superconductors

Through far-infrared studies of La2-xSrxCuO4 single crystals for x = 0.063, 0.07, 0.09, and 0.11, we found that only ~ 0.2 % of the total holes participated in the nearly dissipationless normal state charge transport and superconductivity. We have also observed characteristic collective modes at w ~ 18 cm-1 and 22 cm-1 due to the bound carriers in an electronic lattice (EL) state and the free carriers are massively screened by the EL. Our findings lead us to propose a composite picture of the charge system where the free carriers are coupled to and riding on the EL. This unique composite system of charge carriers may provide further insights into the understanding of the cuprate physics.Comment: 10 pages, 4 figure

Crystal-lattice coupling to the vortex-melting transition in YBa2Cu3O7-d

Distinct discontinuities in the thermal expansion of the crystal lattice are observed at the melting-transition of the vortex lattice in a naturally untwinned reversible YBa2Cu3O7-d-single crystal using high-resolution dilatometry. This coupling between the vortex transition and the crystal lattice demonstrates that the crystal lattice is more than a mere host for the vortices, and it is attributed to a strong pressure dependence of the superconducting transition temperature and thus to the condensation energy at the vortex melting temperature.Comment: 4 pages, 1 figure, 1 tabl

VISIONS: the VISTA Star Formation Atlas: I. Survey overview

Galaxie

Was Paare stark macht: Das Geheimnis einer glücklichen Partnerschaft

Einfühlsam und wissenschaftlich fundiert zeigt der Experte, wie Paare die Klippen des Beziehungsalltags heil umschiffen. Er beschreibt, was es für ein glückliches Miteinander braucht - die kleinen Gesten, die gegenseitige Unterstützung, das offene Gespräch und das Bekenntnis zueinander. Seine Ausführungen und Empfehlungen sind mit neusten wissenschaftlichen Erkenntnissen untermauert; seine Tipps machen Lust aufs Ausprobieren. Dieses Buch zeigt ganz konkret, wie Paare Ihr Liebesglück vor Stress, Abnützung und Gleichgültigkeit dauerhaft schützen können

Acute respiratory health effects of urban air pollutants in adults with different patterns of underlying respiratory disease

OBJECTIVE: Whether underlying chronic respiratory diseases are susceptible factors for symptomatic episodes, which lead to primary-level care, in association with air pollutant exposures is unknown. We evaluated and compared association lag structures between daily ambient levels of nitrogen dioxide (NO2) and total suspended particulates (TSP) and respiratory symptom-related doctor visits in adults with different patterns of underlying chronic respiratory disease.METHODS: In a time-stratified case-crossover analysis nested within a diary panel study, 459 Swiss adult participants with asthma, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and healthy participants recorded occurrence of respiratory-symptom related doctor visits (n = 1,048) in one to six four-week intervals over two years. For each disease subgroup, odds ratios (ORs) for doctor visit were estimated as a function of NO2 or TSP concentrations (per 10 micrograms per cubic meter [µg/m3]) lagged between 0-13 days in a polynomial distributed lag model.RESULTS: Higher ORs for NO2 in participants with COPD (OR: 1.17, 95%CI: 1.02-1.35) and asthma (OR: 1.15, 95%CI: 1.02-1.30) occurred at exposure lags of two and five days, respectively. Doctor visits increased by 9.1% (95%CI: 3.2-15.4%) and 4.2% (95%CI: 1.2-7.2%) over the first week following a 10 µg/m3 increase in NO2 concentration in the COPD and chronic bronchitis subgroups, respectively. The percent increase in the COPD subgroup was significantly greater (p >0.05) when compared with the healthy subgroup. Observed findings were similar for TSP.CONCLUSIONS: Respiratory problems leading to a doctor visit, associated with an increase in exposure to NO2 and TSP, may have a faster dynamic in individuals with COPD

Combinatorial material research : a supramolecular approach to novel polymers

Abstract onl