| 1. |
- Holm, Magnus, et al.
(författare)
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Non-Invasive Assessment of the Atrial Cycle Length during Atrial Fibrillation in Man: Introducing, Validating and Illustrating a New ECG Method
- 1998
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Ingår i: Cardiovascular Research. - 1755-3245. ; 38:1, s. 69-81
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Atrial fibrillation (AF) in man has previously been shown to include a wide variety of atrial activity. Assessment of the characteristics of this arrhythmia with a commonly applicable tool may therefore be important in the choice and evaluation of different therapeutic strategies. As the AF cycle length has been shown to correlate locally with atrial refractoriness and globally with the degree of atrial organization, with, in general, shorter cycle length during apparently random AF compared to more organized AF, we have developed a new method for non-invasive assessment of the AF cycle length using the surface and the esophagus (ESO) ECG. METHODS AND RESULTS: From the frequency spectrum of the residual ECG, created by suppression of the QRST complexes, the dominant atrial cycle length (DACL) was derived. By comparison with multiple intracardiac simultaneously acquired right and left AF cycle lengths in patients with paroxysmal AF, we found that the DACL in lead V1, ranging from 130 to 185 ms, well represented a spatial average of the right AF cycle lengths, whereas the DACL in the ESO ECG, ranging from 140 to 185 ms, reflected both the right and the left AF cycle length, where the influence from each structure depended on the atrial anatomy of the individual, as determined by MRI. In patients with chronic AF, the method was capable of following changes in the AF cycle length due to administration of D,L-sotalol and 5 min of ECG recording was sufficient for the DACL to be reproducible. CONCLUSIONS: We conclude that this new non-invasive method, named 'Frequency Analysis of Fibrillatory ECG' (FAF-ECG), is capable of assessing both the magnitude and the dynamics of the atrial fibrillation cycle length in man.
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| 2. |
- Bengtsson, Daniel, et al.
(författare)
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Zipper performance when mixing ADSL and VDSL in terms of reach and capacity
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this contribution we have examined how the maximum reach vary at different bit rates on a VDSL system, when different numbers of ADSL and VDSL systems share the same binder. In this context it is concluded that when using the Zipper duplex scheme, VDSL can coexist with ADSL in the same binder without a significant degradation in reach. Further, it is shown that the Zipper duplex scheme secure that ADSL is not disturbed by NEXT from VDSL The Zipper performance has also been compared with both a TDD proposal and a FDD proposal. The results from this comparison shows that Zipper outperforms FDD and TDD in terms of extended reach at all studied mixes of ADSL and VDSL sharing the same binder. For example with a moderate number (5) of ADSL disturbers, the Zipper reach is 150 meters longer than for TDD, and is 350 meters longer than for FDD when studying the medium range asymmetrical bit rate (26:3.2 Mbps).
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| 3. |
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| 4. |
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| 5. |
- Olsson, Mats, et al.
(författare)
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NORDJUST-audit.
- 1997
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Rapport (refereegranskat)
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| 6. |
- Seaquist, Jonathan, et al.
(författare)
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A simple method to account for off-nadir scattering in the NOAA/NASA Pathfinder AVHRR Land Data Set
- 1998
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Ingår i: International Joural of Remote Sensing. - : Informa UK Limited. - 1366-5901 .- 0143-1161. ; 19:7, s. 1425-1431
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Tidskriftsartikel (refereegranskat)abstract
- The radiometric distortion of reflected radiation received by the NOAA AVHRR sensor is brought on by the effects of viewing and solar illumination geometry, as well as atmospheric effects. This may lead to a gross underestimation of bioproductivity or crop yield from models which use high temporal resolution NOAA AVHRR data as an input. Accordingly, a simple angular correction method is presented using daily NDVI data over the Sudan from July, 1989 derived from the NOAA/NASA Pathfinder AVHRR Land Data Set. Its simplicity and expediency may render it suitable for operational monitoring programmes such as famine early warning.
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| 7. |
- Seaquist, Jonathan, et al.
(författare)
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Rapid estimation of photosynthetically active radiation over the West African Sahel using the Pathfinder Land Data Set
- 1999
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Ingår i: International Journal of Applied Earth Observation and Geoinformation. - 1569-8432. ; 1:3-4, s. 205-213
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Tidskriftsartikel (refereegranskat)abstract
- Photosynthetically Active Radiation (PAR) is important for assessing both the impact of changing land cover on climate, and for modelling productivity on a regional scale, as well as its potential in areas that are vulnerable to food shortfalls. A relatively simple method that generates spatially comprehensive and representative values of PAR at time scales of 10-days (dekads) or longer is described, tested and implemented over a portion of West Africa. With simple equations to describe the geographical and temporal variation of global radiation receipt at the top of the atmosphere, daily cloud flags from the NOAA/NASA AVHRR Pathfinder Land Data Set (PAL) are used in conjunction with an empirical formula developed by Angstrom and constants tailored to West African conditions to estimate surface receipt of global radiation there. Ground observations of PAR from the HAPEX Sahel experiment (at 13°66' N and 2°53' E from 1992) are used to parameterise the relative sunshine duration variable in the Angstrom relation so as to minimise errors between observed and modelled PAR. Results indicate that PAR may be estimated to within 20 percent of observed values for 28 out of 36 10-day summation periods over a year. End-of-year accumulated PAR is estimated to within 1.96 percent. Normalised root mean square errors (NRMSEs) and normalised mean absolute errors (NMAEs) of 15.69 percent and 12.46 percent, respectively, were obtained for 10-day sums, with values of 10.96 percent and 8.74 percent, respectively, for monthly sums. The spatial variability of end-of-year PAR for 1992 is in accordance with what was expected. Though more accurate methods exist for achieving this, the technique is merited for its ease of application, using an accessible data set, over areas where solar irradiation measurements are lacking.
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| 8. |
- Snekkens, Vidar, et al.
(författare)
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Method for precipitating hemicellulose onto fibres for improved yield and beatability : Förfaringssätt för utfällning av hemicellulosa på fiber för förbättrat utbyte och malbarhet
- 1998
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Patent (populärvet., debatt m.m.)abstract
- A method for continuous cooking of lignocellulosic fibre material, comprising the steps of sequentially (a) in a first stage, impregnating the fibre material in an impregnation liquid comprising alkali metal hydroxide, and thereafter withdrawing (14, 514) a spent impregnation liquid; (b) in a second stage, cooking the fibre material in a cooking liquor comprising alkali metal hydroxide; and (c) in a third stage, adding (A), to said fibre material, a liquid which is rich in hemicellulose, said liquid preferably comprising at least a part (14a, 514a) of said withdrawn spent impregnation liquid. In a fourth stage (d), the fibre material is cooked in a cooking liquor comprising the liquid added in the third stage, whereby the fibre material is subjected to a retention time of at least 1 hour in said fourth stage.
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| 9. |
- Wahlqvist, Mattias, et al.
(författare)
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Description of Telias OFDM based proposal
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document gives an overview of Telias OFDM based proposal for UTRA and should be cinsidered as an input to the OFDM concept group within SMG 2. The document describes the fundamental frame structure, principles of the detection, modulation, coding and synchronization. Further, the channel structure, the resource management and handover principles are outlined
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| 10. |
- Werdelin, Lars, et al.
(författare)
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How the leopard got its spots: a phylogenetic view of the evolution of felid coat patterns
- 1997
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Ingår i: Biological Journal of the Linnean Society. - 0024-4066 .- 1095-8312. ; 62, s. 383-400
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Tidskriftsartikel (refereegranskat)abstract
- The current theory of felid coat pattern evolution proposes that the primitive pattern is one of relatively large spots that break down into smaller spots (here denoted flecks) and rosettes while at the same time leading to various striped patterns as sidelines. We have coded the coat patterns of felids into uniform, flecks, rosettes, vertical stripes, small blotches and blotches and show by mapping these character states onto phylogenies of the family that the current theory is flawed. Instead, the primitive pattern appears to be flecks and it is from this type that nearly all other types have developed. The robustness of this hypothesis is shown by the fact that it remains unchanged regardless of which of several quite different, competing phylogenies of the family is used. The pattern of transformations reconstructed is not predicted by current theories of pattern formation and we suggest that modellers pay closer attention to the phylogenetic histories of the features that they model.
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