| 1. |
- Alberdi, A., et al.
(författare)
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The high-frequency compact radio structure of the peculiar quasar 4C 39.25
- 1997
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Ingår i: Astronomy and Astrophysics. - : Springer-Verlag. - 0004-6361 .- 1432-0746. ; 327:2, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtained from VLBI observations at λ1.3cm, λ7mm, and λ3mm wavelengths. These maps and Gaussian model-fits show that the milli-arcsecond to sub-milliarcsecond structure of 4C 39.25 consists of a complex bent core-jet structure with embedded moving and stationary VLBI components. Facilitated by the small observing beams and high angular resolutions obtained at mm-wavelengths, we measured the relative positions of the jet components with an accuracy of a few hundred micro-arcseconds. This allows the detailed followup of the ongoing merging process of a westward superluminally moving component (b_) with a stationary component a_, located at ~2.9 mas east of the putative core d_. In contrast to the other components of the structure with steeper spectra, the westernmost component d_ exhibits an inverted spectrum peaking between λ7mm and λ3mm, thus further supporting its identification as the VLBI core, self-absorbed at longer wavelengths. From two VLBI maps obtained nearly simultaneously at λ7mm and λ1.3cm, we made the first spectral index map of 4C 39.25 in this wavelength regime. The main characteristics of the spectral index distribution of the jet are pronounced changes of the spectral index between orientations parallel and transverse to the jet axis. Near the merging components a_ and b_ the spectral index steepens with increasing separation from d_. However, in the bridge of emission c_, which connects d_ with a_ and b_, the spectral index gradient has a direction transverse to the jet axis, suggesting a frequency dependent jet curvature and edge-brightening. A brief discussion of this behaviour within current jet models is presented.
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| 2. |
- Baerveldt, Albert-Jan, et al.
(författare)
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A low-cost and low-weight attitude estimation system for an autonomous helicopter
- 1997
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Ingår i: IEEE International Conference on Intelligent Engineering Systems, Proceedings, INES. - Piscataway, N.J. : IEEE Press. - 0780336275 ; , s. 391-395
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a low-cost and low-weight attitude estimation system for an autonomous helicopter is presented. The system is based on an inclinometer and a rate gyro. The data coming from the sensors is fused through a complementary filter. In this way the slow dynamics of the inclinometer can be effectively compensated. Tests have shown that we obtained a very effective attitude estimation system.
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| 3. |
- Bengtsson, Lars, 1958-, et al.
(författare)
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REMAP massively parallel computer platform for neural computations
- 1997
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Ingår i: Proceedings of the Third International Conference on Microelectronics for Neural Networks (MicroNeuro’93). ; , s. 47-62
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Konferensbidrag (refereegranskat)abstract
- The REMAP project addresses questions related to the use of massively parallel, distributed computing in embedded systems. Of specific interest is the execution of artificial neural network algorithms on multiple, cooperating processor arrays. This paper concentrates on the recently finished, and currently used, processor array prototype, REMAP-β, of SIMD (Single Instruction stream, Multiple Data streams) type. The architecture and implementation of the computer is described, both its overall structure and its constituent parts. Following this comes a discussion of its use as an architecture laboratory, which stems from the fact that it is implemented using FPGA (Field Programmable Gate Array) circuits. As an architecture laboratory the prototype can be used to implement and evaluate, e.g., various Processing Element (PE) designs. A couple of examples of PE architectures, including one with floating-point support, are given. The mapping of important neural network algorithms on processor arrays of this kind is shown, and possible tuning of the architecture to meet specific processing demands is discussed. Performance figures are given as well as implications for future VLSI implementations of the array.
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| 4. |
- Boström, Barbro, et al.
(författare)
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Survey of post-operative patients' pain management
- 1997
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Ingår i: Journal of Nursing Management. - : Blackwell Publishing Ltd.. - 0966-0429 .- 1365-2834. ; 5:6, s. 341-349
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Tidskriftsartikel (refereegranskat)abstract
- Although effective pain treatment is available for both cancer-related pain and acute post-operative pain, many patients suffer unnecessarily. The aim of this study was to evaluate post-operative patients' pain management. A descriptive survey study was conducted in a 460-bed acute hospital in the southwestern part of Sweden. One hundred post-operative inpatients, on their second post-operative day, took part in the study. They were consecutively selected from six surgical wards. Data were collected using an interview questionnaire designed by the American Pain Society and analysed by descriptive and inferential statistics. At the time of the interview, 29 of the patients reported moderate to severe pain. Regarding the patients' worst pain experienced during the last 24 h, 79 of them reported moderate to very severe pain. Significant correlations were found between reported poor pain relief after pain medication and high intensity of pain both within the last 24 h and at the time of the interview. Eighty-three patients were satisfied with the way nurses treated their pain, while 64 patients were satisfied with the way physicians treated their pain. However, the higher the pain intensity experienced by the patients the less satisfied they were. The fact that patients do not know what kinds of relief are available may be one reason for the patients expressing satisfaction despite being in pain, another that the patients judge the kindness of the staff rather than their way of treating the pain. The field of pain management is rapidly changing requiring professional knowledge and experience in order to ensure pain management of good quality.
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| 5. |
- Bååth, Lars, 1948-
(författare)
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A method to simultaneously measuring the position of more than one surface in metallurgical processes
- 1997
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Patent (populärvet., debatt m.m.)abstract
- A method for measuring the position of at least one surface in a metallurgical process which includes the steps of providing a metallurgical melt, the metallurgical melt including at least a metal portion and a slag layer, providing a signal generator for generating signals at a plurality of frequencies over a frequency band, and providing an antenna for receiving the signals generated by the signal generator and for transmitting circularly polarized radio waves at the plurality of frequencies over the frequency band. The invention further includes the steps of disposing the antenna adjacent the metallurgical melt, transmitting the circularly polarized radio waves from the antenna toward the metallurgical melt, the circularly polarized radio waves being transmitted by the antenna at the plurality of frequencies over the frequency band, receiving reflected images of the transmitted radio waves through the antenna, the received reflected images of the transmitted radio waves having a substantially opposite circular polarization from the transmitted circularly polarized radio waves, determining a phase displacement between the transmitted radio waves and the received reflected images of the transmitted radio waves, transforming the determined phase displacement from a frequency to a time plane, and determining from the time plane transform a position of at least one surface of at least one of the metal portion and the slag layer.
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| 6. |
- Bååth, Lars, 1948-, et al.
(författare)
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High resolution interferometry of the QSO 1422+202
- 1997
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Ingår i: Astronomy and Astrophysics. Supplement Series. - Berlin : Springer. - 1286-4846 .- 0365-0138. ; 125:1, s. 453-458
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Tidskriftsartikel (refereegranskat)abstract
- We present VLA A-array observations at 8.4 and 15GHz and European VLBI Network (EVN) observations at 1.6GHz of the radio source 1422+202. It is suggested that 1422+202 is a Medium-size Object in the evolutionary sequence from Compact Steep-spectrum Sources to larger sized radio sources. The VLBI data were analysed with the phase referencing technique and we show that the EVN can work as a phase stable instrument for separations between the calibrator source and the target source up to ~ 10 degrees. With the VLA and VLBI observations we investigate some of the issues about the nucleus of 1422+202 and we discuss the possible cause for the low frequency variability detected while monitoring the source.
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| 7. |
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| 8. |
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| 9. |
- Eriksson, Peder G., et al.
(författare)
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Nitrogen removal in a wastewater reservoir : The importance of denitrification by epiphytic biofilms on submersed vegetation
- 1997
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Ingår i: Journal of Environmental Quality. - Madison, United States : American Society of Agronomy. - 0047-2425 .- 1537-2537. ; 26:3, s. 905-910
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine the importance of epiphytic denitrifying bacteria on submersed vegetation in removing N from a shallow nutrient-enriched freshwater ecosystem. The investigation was conducted during the summer of 1994 in a surface now reservoir receiving municipal tertiary-treated wastewater. The submersed vegetation in the reservoir was dominated by Potamogeton pectinatus L. and filamentous green algae (FGA). The N loading was 2300 mg N h(-1) m(-2) and the N removal, calculated as the mean difference between influent and effluent N, was 190 mg N h(-1) m(-2) (8%). The majority of influent N consisted of NH4+, but the main part of the N removal was due to the removal of NO3- whereas no net retention of NH4+ was found. Mean total soluble solids and BOD7 retention was 69 and 38%, respectively, Denitrification measurements were conducted in darkness at in situ temperature in microcosms with P. pectinatus, FGA, or infect sediment cores. Epiphytic denitrification ranged between 0.21 to 7.0 mg N h(-1) m(-2) reservoir surface area depending on the abundance of the submersed vegetation (5-140 g DW m(-2)). Sediment denitrification was 4.7 mg N h(-1) m-L reservoir surface area. The mean assimilative N uptake of the submersed vegetation and epiphyton was 3.4 and 1.6 mg N h(-1) m(-2) reservoir surface area, respectively. Measured N removal rates through plant uptake and denitrification could only account for a minor part of the N removal observed by mass balance. However, microcosm denitrification measurements underestimate actual denitrification. Thus, the major part of the N removal was most likely due to denitrification. In conclusion, this study indicates that denitrification in epiphytic microbial communities on submersed vegetation can be of significant importance for the N removal in nutrient-enriched freshwater ecosystems.
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| 10. |
- Fridlund, Bengt
(författare)
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The case study as a research strategy
- 1997
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Ingår i: Scandinavian Journal of Caring Sciences. - Oxford : Blackwell Publishing. - 0283-9318 .- 1471-6712. ; 11:1, s. 3-4
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Tidskriftsartikel (refereegranskat)abstract
- A research strategy seldom used in the caring sciences is the case study. A case study is an empirical in-depth inquiry about an individual, family, group or organization. It is preferable when 'how' and 'why' questions are asked. The case study is mainly used to explain those causal links in real-life intervention that are too complex for either the survey or experimental strategies. Like other research strategies, its design includes questions or propositions, units of analysis, the logic linking the data to the questions or propositions, and the interpretations of the outcomes. A case study can be reported as a single case or as a compilation of a series of cases. In conclusion a case study is a simple and excellent way for a care professional to present him or herself to the scientific world.
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