| 1. |
- Glauser, A. M., et al.
(författare)
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Characterizing exoplanets in the visible and infrared: A spectrometer concept for the EChO space mission
- 2013
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Ingår i: Journal of Astronomical Instrumentation. - 2251-1725 .- 2251-1717. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Transit-spectroscopy of exoplanets is one of the key observational techniques used to characterize extrasolar planets and their atmospheres. The observational challenges of these measurements require dedicated instrumentation and only the space environment allows undisturbed access to earth-like atmospheric features such as water or carbon dioxide. Therefore, several exoplanet-specific space missions are currently being studied. One of them is EChO, the Exoplanet Characterization Observatory, which is part of ESA's Cosmic Vision 2015-2025 program, and which is one of four candidates for the M3 launch slot in 2024. In this paper we present the results of our assessment study of the EChO spectrometer, the only science instrument onboard this spacecraft. The instrument is a multi-channel all-reflective dispersive spectrometer, covering the wavelength range from 400 nm to 16μm simultaneously with a moderately low spectral resolution. We illustrate how the key technical challenge of the EChO mission - the high photometric stability - influences the choice of spectrometer concept and fundamentally drives the instrument design. First performance evaluations underline the suitability of the elaborated design solution for the needs of the EChO mission.
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| 2. |
- Gokeler, Alli, et al.
(författare)
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Proprioceptive deficits after ACL injury: are they clinically relevant?
- 2012
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Ingår i: British journal of sports medicine. - : BMJ. - 1473-0480 .- 0306-3674. ; 46:3, s. 180-192
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Forskningsöversikt (refereegranskat)abstract
- Objective To establish the clinical relevance of proprioceptive deficits reported after anterior cruciate ligament (ACL) injury. Material and methods A literature search was done in electronic databases from January 1990 to June 2009. Inclusion criteria for studies were ACL deficient (ACL-D) and ACL reconstruction (ACL-R) articles written in English, Dutch or German and calculation of correlation(s) between proprioception tests and clinical outcome measures. Clinical outcome measures were muscle strength, laxity, hop test, balance, patient-reported outcome, objective knee score rating, patient satisfaction or return to sports. Studies included in the review were assessed on their methodological quality. Results In total 1161 studies were identified of which 24 met the inclusion criteria. Pooling of all data was not possible due to substantial differences in measurement techniques and data analysis. Most studies failed to perform reliability measurements of the test device used. In general, the correlation between proprioception and laxity, balance, hop tests and patient outcome was low. Four studies reported a moderate correlation between proprioception, strength, balance or hop test. Conclusion There is limited evidence that proprioceptive deficits as detected by commonly used tests adversely affect function in ACL-D and ACL-R patients. Development of new tests to determine the relevant role of the sensorimotor system is needed. These tests should ideally be used as screening tests for primary and secondary prevention of ACL injury.
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| 3. |
- Lagerros, JSV, et al.
(författare)
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ISOPHOT polarization measurements of the asteroids (6) Hebe and (9) Metis at 25 mu m
- 1999
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Ingår i: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 142:2, s. 454-463
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Tidskriftsartikel (refereegranskat)abstract
- The subsurface thermal IR emission of asteroids becomes linearly polarized when scattered across the surface, The disk integrated mid-IR Stokes parameters are computed by extending the new thermophysical model by Lagerros (1996, Astron. Astrophys. 315, 62
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| 4. |
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| 5. |
- Muller, T., et al.
(författare)
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Herschel celestial calibration sources
- 2014
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 37:2, s. 253-330
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Tidskriftsartikel (refereegranskat)abstract
- Celestial standards play a major role in observational astrophysics. They are needed to characterise the performance of instruments and are paramount for photometric calibration. During the Herschel Calibration Asteroid Preparatory Programme approximately 50 asteroids have been established as far-IR/sub-mm/mm calibrators for Herschel. The selected asteroids fill the flux gap between the sub-mm/mm calibrators Mars, Uranus and Neptune, and the mid-IR bright calibration stars. All three Herschel instruments observed asteroids for various calibration purposes, including pointing tests, absolute flux calibration, relative spectral response function, observing mode validation, and cross-calibration aspects. Here we present newly established models for the four large and well characterized main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (21) Lutetia which can be considered as new prime flux calibrators. The relevant object-specific properties (size, shape, spin-properties, albedo, thermal properties) are well established. The seasonal (distance to Sun, distance to observer, phase angle, aspect angle) and daily variations (rotation) are included in a new thermophysical model setup for these targets. The thermophysical model predictions agree within 5 % with the available (and independently calibrated) Herschel measurements. The four objects cover the flux regime from just below 1,000 Jy (Ceres at mid-IR N-/Q-band) down to fluxes below 0.1 Jy (Lutetia at the longest wavelengths). Based on the comparison with PACS, SPIRE and HIFI measurements and pre-Herschel experience, the validity of these new prime calibrators ranges from mid-infrared to about 700 mu m, connecting nicely the absolute stellar reference system in the mid-IR with the planet-based calibration at sub-mm/mm wavelengths.
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| 6. |
- Speakman, John R., et al.
(författare)
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Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure
- 2023
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Ingår i: Nature Metabolism. - : NATURE PORTFOLIO. - 2522-5812. ; 5:4, s. 579-588
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is caused by a prolonged positive energy balance(1,2). Whether reduced energy expenditure stemming from reduced activity levels contributes is debated(3,4). Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.
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