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• 301.
Onsala Space Observatory, Onsala, Sweden.
mm VLBI1993In: VLBI Technology – Progress and Future Observational Possibilities: Proceedings of the International Symposium Held at Kyoto International Conference Hall on September 6-10, 1993 / [ed] Tetsuo Sasao, Seiji Manabe, Osamu Kameya & Makoto Inoue, Tokyo: Terra Scientific Publishing Company , 1993, p. 70-74Chapter in book (Refereed)

Very long Baseline Interferometry (VLBI) has now made its break-through into the mm wavelength regime. A global VLBI array has produced maps of radio sources at $\lambda$3 mm since 1988 and development is under way to improve the sensitivity for VLBI also at $\lambda$1 mm. This contribution discusses the present state of mm VLBI and the future developments.

• 302.
Tests of VLBI systems at Shanghai and Urumqi1996Report (Refereed)
• 303.
Haystack Observatory. NASA Goddard Space Flight Center. Haystack Observatory. NVI, Inc.lGoddard Space Flight Center. NASA Goddard Space Flight Center.
Team China report1998Report (Refereed)
• 304.
Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
Istituto di Radioastronomia del C.N.R., Bologna, Italy. Istituto di Radioastronomia del C.N.R., Bologna, Italy.
High resolution interferometry of the QSO 1422+2021997In: Astronomy and Astrophysics. Supplement Series, ISSN 1286-4846, Vol. 125, no 1, p. 453-458Article in journal (Refereed)

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.

• 305.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
A closer look at active galactic nuclei — the great engines of the universe1992In: Physica scripta. T, ISSN 0281-1847, Vol. T43, p. 57-66Article in journal (Refereed)

The intensive radio emission from powerful radio galaxies and quasars Make these attractive candidates to become "standard candles" to probe the Universe. This paper discusses this possibility and the physics of the radio sources.

• 306.
Onsala Space Observatory, Onsala, Sweden.
AGN Variability and VLBI1994In: Multi-Wavelength Continuum Emission of Agn: Proceedings of the 159th Symposium of the International Astronomical Union, Held in Geneva, Switzerland, August 30 – September 3, 1993 / [ed] T.J.-L. Courvoisier & A. Blecha, Dordrecht: Kluwer Academic Publishers, 1994, p. 181-186Chapter in book (Refereed)

This contribution discusses the connection between variability in radio and optical with structural variations observed with VLBI. Structural changes do not have to start in the core, and intensity variations may be caused by components in the jet outside the core. The scenario is probably more complicated than present day theories assume.

• 307.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Astrophysical global interferometry at Onsala Space Observatory1982In: Reports from the Observatory of Lund, ISSN 0349-4217, Vol. 18, p. 23-25Article in journal (Refereed)
• 308.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Global Fringe Fitting Applied to 100 GHZ VLBI Data1991In: Frontiers of VLBI: Proceedings of the International VSOP Symposium held at the Institute of Space and Astronautical Science on December 5-7, 1989, and Proceedings of the mm-Wave VLBI Workshop held at the Nobeyama Radio Observatory on December 8-9, 1989 / [ed] H. Hirabayashi, M. Inoue & H. Kobayashi, Tokyo: Universal Academy Press , 1991, p. 353-359Chapter in book (Refereed)

Earlier epoches of mm VLBI observations relied on single baseline fit of delays and rates to find the fringes. This approach does not, however, make use of all available information and therefore is less sensitive than is necessary. Global fringe fitting makes use of all simultaneous data to find station related clock offsets and rates over a certain period of time. © Universal Academy Press, Inc.

• 309.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Global fringe fitting applied to Mk3 VLBI data1991In: Radio Interferometry: Theory, Techniques, and Applications / [ed] T.J. Cornwell & R.A. Perley, San Francisco, USA: Astronomical Society of the Pacific , 1991, p. 321-325Conference paper (Refereed)

A system has been developed where data from a Mk3 VLBI processor can be read into the AIPS-package. Multiband and single-band delays can then be fitted globally by station. The technique has been used to phasereference a background to two radiogalaxies in the Abell cluster A2634.

• 310.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
High resolution images of Blazar cores1992In: Variability of Blazars: Proceedings of a conference in honour of the 100th anniversary of the birth of academician Yrjö Väisälä, held at Tuorla Observatory, University of Turku, Finland, January 6-10, 1991 / [ed] E. Valtaoja & M. Valtonen, Cambridge, UK: Cambridge University Press, 1992, p. 196-204Conference paper (Refereed)
• 311.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
High Resolution Observations of Low Frequency Variables at 932 MHz1987In: The Impact of VLBI on Astrophysics and Geophysics: Proceedings of the 129th Symposium of the International Astronomical Union held in Cambridge, Mass., U.S.A., May 10-15, 1987 / [ed] Reid, M. J. & Moran, J. M., Dordrecht: Kluwer Academic Publishers, 1987, p. 117-118Chapter in book (Refereed)

Fifteen sources known to be varying at low frequencies have been observed at six epochs during 1983–84 with a global VLBI array. Some of the sources show structural variations similar to the superluminals. Beaming effect may therefore play an important role at low as well as at higher frequencies.

• 312.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Mapping in Practice1989In: Very Long Baseline Interferometry: Techniques and Applications / [ed] Felli, Marcello & Spencer, Ralph E., Dordrecht: Kluwer Academic Publishers, 1989, p. 199-230Chapter in book (Refereed)

The purpose of this lecture is to introduce the VLBI user to the practical details of mapping radio sources. I will concentrate on data processing and mapping with the AIPS (Thompson and D’Addario, 1982)-package. Other data reduction systems do exist, e.g. the Caltech-package and OLAF. These differ from AIPS mostly in the strategy for reaching the final and “best” map. It is more important to know the method and to be careful than what reduction procedure is used.

• 313.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Millimetre VLBI capability status1993In: Sub-arcsecond Radio Astronomy: Proceedings of the Nuffield Radio Astronomy Laboratories' conference, held in Manchester, July 20–24, 1992 / [ed] R. J. Davis & R. S. Booth, Cambridge: Cambridge University Press, 1993, p. 431-433Chapter in book (Refereed)

The development of new reveiver and data reduction techniques have now made VLBI at mm wavelengths possible. This contribution discusses the capability of the present and future VLBI networks at λ1 and 3mm and compares with radio interferometers at other wavelength regimes.

• 314.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
mm VLBI vs. VSOP1991In: Frontiers of VLBI: Proceedings of the International VSOP Symposium held at the Institute of Space and Astronautical Science on December 5-7, 1989, and Proceedings of the mm-Wave VLBI Workshop held at the Nobeyama Radio Observatory on December 8-9, 1989 / [ed] H. Hirabayashi, M. Inoue & H. Kobayashi, Tokyo: Universal Academy Press , 1991, p. 197-201Chapter in book (Refereed)

VSOP-to-ground VLBI and mm VLBI are both needed if we want to further increase our knowledge of quasars, radio galaxies and their radio jets, mm VLBI will be a better instrument to study the "central engine" while satellite VLBI will better show the structure of the jets. The two instruments complement each other, and it is important to have a close collaboration. © Universal Academy Press, Inc.

• 315.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
New millimetric VLBI results1992In: Extragalactic radio sources - from beams to jets: Proceedings of the 7th IAP Meeting held at the Institut d'Astrophysique de Paris, Paris, France 2-5 July 1991 / [ed] J. Roland, H. Sol and G. Pelletier, Cambridge: Cambridge University Press, 1992, p. 137-144Conference paper (Refereed)
• 316.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Radiogalaxer och kvasarer1990In: Astronomisk årsbok 1991, Johanneshov: Inova , 1990, p. 71-77Chapter in book (Refereed)
• 317.
Institutionen för astronomi, Lunds universitet, Lund, Sverige.
Radiospår i galaxhopar1973In: Astronomisk tidsskrift, ISSN 0004-6345, Vol. 6, no 1, p. 18-24Article in journal (Other academic)
• 318.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Results from 100 GHz VLBI1991In: Frontiers of VLBI: Proceedings of the International VSOP Symposium held at the Institute of Space and Astronautical Science on December 5-7, 1989, and Proceedings of the mm-Wave VLBI Workshop held at the Nobeyama Radio Observatory on December 8-9, 1989 / [ed] H. Hirabayashi, M. Inoue & H. Kobayashi, Tokyo: Universal Academy Press , 1991, p. 285-295Chapter in book (Refereed)

Development of receiver and data reduction techniques have now made it possible to produce hybrid maps from global VLBI experiments observing at 100 GHz. Maps are shown here of the compact radio sources 3C 273, 3C 345, 3C 84, BL Lac and OJ 287 with angular resolution of 50 μas. The component born during the 1988 outburst of 3C 273 is seen only 2 month after its birth. The jet of 3C 345 is seen to have a larger curvature than has previously been observed.A component is seen moving outwards from the core of 3C84 with a speed of ≈21000 km sec-1. © Universal Academy Press, Inc.

• 319.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Superluminal Motion in CTA 1021987In: Superluminal Radio Sources: Proceedings of a Workshop in honor of Professor Marshall H. Cohen, held at Big Bear Solar Observatory, California, October 28-30, 1986 / [ed] Zensus, J. Anton & Pearson, Timothy J., Cambridge: Cambridge University Press, 1987, p. 206-210Chapter in book (Refereed)
• 320.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
The Milliarcsecond Structure of some Extragalactic Objects1980Doctoral thesis, comprehensive summary (Other academic)
• 321.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Varying gamma in 3C2731992In: Variability of Blazars: Proceedings of a conference in honour of the 100th anniversary of the birth of academician Yrjö Väisälä, held at Tuorla Observatory, University of Turku, Finland, January 6-10, 1991 / [ed] E. Valtaoja & M. Valtonen, Cambridge: Cambridge University Press, 1992, p. 229-233Conference paper (Refereed)
• 322.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
VLBI monitoring of BL Lac objects1983In: Highlights of Astronomy: as presented at the ... General assembly of the IAU. Vol. 6, As presented at the XVIIIth General assembly of the IAU, 1982 [in Patras, Greece, 17-26 August] / [ed] Richard M. West, Dordrecht: D. Reidel Publishing Group, 1983, p. 742-742Chapter in book (Refereed)
• 323.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
VLBI Monitoring of Bl-Lacertae Objects1984In: VLBI and Compact Radio Sources: Symposium no. 110 held in Bologna, Italy, June 27-July 1, 1983 / [ed] R. Fanti, K. Kellermann & G. Setti, Dordrecht: D. Reidel Publishing Group, 1984, p. 127-130Conference paper (Refereed)

This is a report on an ongoing project designed to study structural variations on the milliarcsecond scale in four BL Lac-type objects. The observations are made at λ6 cm with a global VLBI network consisting of the combined US and European networks. Hybrid maps at three epochs are presented for each of the sources AO 0235+164,0735+178, Mk 421, and 1749+701.

• 324.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
VLBI observations at 100 GHz1990In: Parsec-Scale radio jets: proceedings of a Workshop held at the National Radio Astronomy Observatory, Socorro, New Mexico, October 17-18, 1989 / [ed] Zensus, J. Anton & Pearson, Timothy J., Cambridge: Cambridge University Press, 1990, p. 91-97Chapter in book (Refereed)

We present maps using VLBI at 100 GHz of three sources, 3C273, 3C345, and 3C84. The resolution is 50 μas, the highest yet achieved.

• 325.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
MmVLBI - High resolution imaging1991In: Radio Interferometry: Theory, Techniques, and Applications / [ed] T.J. Cornwell & R.A. Perley, San Francisco, USA: Astronomical Society of the Pacific , 1991, p. 326-329Conference paper (Refereed)

Hybrid maps at 100 GHz have been produced using VLBI data obtained at 100 GHz. The observations and global fringe fitting technique used to produce the maps are briefly described.

• 326.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Massachusetts Institute of Technology, Cambridge, MA, USA. Massachusetts Institute of Technology, Cambridge, MA, USA. Massachusetts Institute of Technology, Cambridge, MA, USA. Massachusetts Institute of Technology, Cambridge, MA, USA. Haystack Observatory, Westford, MA, USA. Haystack Observatory, Westford, MA, USA. Haystack Observatory, Westford, MA, USA. Haystack Observatory, Westford, MA, USA. Goddard Space Flight Center, Greenbelt, MD, USA. Goddard Space Flight Center, Greenbelt, MD, USA. Jet Propulsion Laboratory, Pasadena, CA, USA.
Time-Dependent Radio Fine Structure of the Compact Sources NRAO 150 and 4C 39.251980In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 86, no 3, p. 364-372Article in journal (Refereed)

Very long baseline interferometer observations at 7.85 GHz have been used to probe the milliarcsecond structure of the unidentified, very compact radio source NRAO 150 and QSO 4 C 39.25. NRAO 150 exhibited no structural variations from 1972 to the end of 1974. A model with two circular Gaussian components fits the data well. NRAO 150 had a flux density of 7.6 plus or minus 0.5 Jy in the compact component; 4 C 39.25 showed a two-component structure, the components having a separation of (2.02 plus or minus 0.05 arc sec) x 10 to the -3rd power. The upper bound on the speed of transverse separation is 0.0001 arc sec per year or less than 2.7 c. From the spectrum there are also indications of a third, larger component.

• 327.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden. Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Owens Valley Radio Observatory, Big Pine, CA, USA. Helsinki University of Technology, Radio Laboratory, Espoo, Finland. Netherlands Foundation for Radio Astronomy, Dwingenloo, The Netherlands.
The Radio Fine Structure of the BL Lacertae Objects AO0235+164, 0735+178, BL Lac, 1749+701, Mk 421 and 3C 66 A at 5 GHz1981In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 96, no 1-2, p. 316-324Article in journal (Refereed)

Very long baseline interferometer observations at 4997 MHz (lambda = 6 cm) on European and intercontinental baselines with lengths up to 1.35 108lambda have been used to probe the milliarc s structure of the BL Lacertae objects AO 0235+164, 0735+178, BL Lac, 1749+701, Mk 421, and 3C 66A. Two sets of observations are reported, made in November 1978 and March 1979. AO 0235+164 and 0735+178 both showed structures consisting of a very bright, unresolved core and a jet-like component extending ˜5".4 10-3 along position angle ˜20° and ˜4".2 10-3 along position angle ˜45°, respectively. AO 0235+164 contained more than 98% of the total flux density within a diameter of ≲ 36" 10-3. BL Lac, 1749+701 and Mk 421 all showed evidence for a complex structure of several components, including an unresolved core. 3 C 66A was elongated along position angle ˜ -45°.

• 328.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
EVN as a phase stable interferometer1991In: Radio Interferometry: Theory, Techniques, and Applications / [ed] T. J. Cornwell & R.A. Perley, San Francisco, USA: Astronomical Society of the Pacific Conference , 1991, p. 298-301Conference paper (Refereed)
• 329.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Owens Valley Observatory, Pasadena, CA, USA. Owens Valley Observatory, Pasadena, CA, USA. Northeast Radio Observatory Corp., Haystack Observatory, Westford, MA, USA. University of California, Berkeley, CA, USA. Owens Valley Observatory, Pasadena, CA, USA. Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden. University of California, Berkeley, CA, USA. Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden. University of California, Berkeley, CA, USA. UIniversity of Massachusetts, Amherst, MA, USA. NRAO, Tucson, AZ, USA. Nobeyama Radio Observatory, Minamimaki, Nagano, Japan. Owens Valley Observatory, Pasadena, CA, USA. Nobeyama Radio Observatory, Minamimaki, Nagano, Japan. Center for Astrophysics, Cambridge, MA, USA. Nobeyama Radio Observatory, Minamimaki, Nagano, Japan. NRAO, Tucson, AZ, USA. University of California, Berkeley, CA, USA. UIniversity of Massachusetts, Amherst, MA, USA. Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
The microarcsecond structure of 3C 273 at 3 MM1991In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 241, no 1, p. L1-L4Article in journal (Refereed)

Recent improvements in data analysis and receiver techniques have allowed us to produce a map of the 100GHz emission from the compact radio source 3C273 with the unsurpassed resolution of 50-mu-as (microarcseconds). Our map shows that the structure within 300-mu-as (approximately 1.5.10(18).h-1 cm) has a position angle significantly different from the position angle of the jet observed at lower frequencies. There are also indications in our map that the inner structure has a more pronounced wiggling structure than has been observed on larger scales. The observations were made about 60 days from the start of the outburst of 1988. Most of the flux from the outburst is concentrated in a component which is elongated approximately (56 x 5).10(16).h-1 cm perpendicular to the overall jet-axis. The distance between this component and the core is approximately 128-mu-as, which corresponds to the distance expected from an apparent velocity of approximately 800-mu-as year-1.

• 330.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
VLBI observations of active galactic nuclei at 3 MM1992In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 257, no 1, p. 31-46Article in journal (Refereed)

Recent improvements in data analysis and receiver techniques have allowed us to produce maps of the 100 GHz emission from the compact cores of active galactic nuclei with the unsurpassed resolution of 50-mu-as (microarcseconds). We present here hybrid maps of a set of compact radio sources observed at two epochs with a global VLBI array. The high resolution enables us to show details of active galactic nuclei on size scales of 10(16)-10(17) cm. Jets are shown to be more curved in these inner parts than further out in the areas mapped with VLBI at lower frequencies. Our maps of the quasar 3C345 show that the curvature seen with lower resolution instruments continues very close to the core. New components are seen separating from the cores of 3C84 and BL Lac. We observe a component in 3C84 separating from the core with an apparent speed approximately 21000 km sec-1. The radio source OJ287 is still unresolved with our array, having a core size of less-than-or-similar-to 10(17) cm. There is no indication of any compact component in 3C279 which would be associated with the outburst in integrated flux density which happened some months before our observation. The flux density of the most compact component we observe in 3C279 agrees well with that of the quiet core as extrapolated from its radio spectrum at lower frequencies. The inner part of the radio jet of the giant elliptical galaxy M87 also shows a continuation of the structure on a larger size scale, with a structure we interpret as parts of a helical pattern. No fringes were found for 4C39.25 or Sgr A.

• 331.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Max-Planck-Institut für Radioastronomie, Bonn, Germany. Space Research Institute, Moscow, USSR. Space Research Institute, Moscow, USSR. Space Research Institute, Moscow, USSR. Crimean Astrophysical Observatory, USSR Academy of Sciences, P/O Nauchny, Crimea, USSR. National Radio Astronomy Observatory, Goddard Space Flight Center, Greenbelt, MD, USA.
High Resolution Observations of the QSO 3C 345 at 1.3 centimeters1981In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 243, p. L123-L126Article in journal (Refereed)

High-resolution VLBI observations made at a frequency of 22.235 GHz of the quasar 3C 345 are discussed. Antennas located at the Crimean Astrophysical Observatory, USSR; Onsala, Sweden; Effelsberg, West Germany; and the Haystack Observatory, Massachusetts were employed at 4-min integration times to provide baselines ranging up to 5.5 x 10 to the 8th wavelengths. About 40% of the total flux density of 7.85 Jy, observed in November 1977, and 8.05 Jy, observed in October 1978, is found to originate in an unresolved component of the quasar core in a region less than 0.1 milliarcsec in diameter. The elongated jet-like component of the quasar is observed to contain several peaks of emission extending up to 6 milliarsec from the core which decreased in extent between the two observations.

• 332.
Onsala Space Observatory, Onsala, Sweden.
Shanghai Observatory, China.
IMAGES OF THE BL LACERTAE OBJECT 1749+701 AT 5 GHZ1992In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 262, no 1, p. 1-7Article in journal (Refereed)

This paper presents images of 1749+701 from data obtained between 1980 and 1983 as a part of our VLBI programme to monitor a subsample of BL Lac objects at 5GHz. Our images show that this source has a complex structure with a jet pointing towards the north-west at a position angle of about -65-degrees. The brightest component is growing in extension along this position angle. We suggest this to be the core and that the growing extension was caused by a shock generated during an outburst and moving out along the jet. From the extension rate, we obtain an angular separation speed of 0.18 mas yr-1, which corresponds to an apparent transverse speed of 5c. The distances and position angles of two outer components seem remarkably constant. The phenomenon can be understood through a model in which a relativistic jet bends such that its axis is very close to the line of sight in two points. We also deduce that the Lorentz factor must be 4.5 less-than-or-equal-to gamma less-than-or-equal-to 6.5 and that the viewing angle must be 5-degrees less-than-or-equal-to theta less-than-or-equal-to 10-degrees. In this paper, we also present two images obtained from 5GHz MERLIN and combined MERLIN-VLBI data respectively. These maps show that there is a weak component located at a distance of 0.42 arcsec from the core at p.a -155-degrees.

• 333.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire, United Kingdom. Purple Mountain Observatory, Nanjing, China.
0735+178: The cosmic conspiracy1991In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 250, no 1, p. 50-56Article in journal (Refereed)

This paper discusses a radio outburst in the BL Lac-object 0735+178 which started in early 1988, ended during 1990 and was succeeded by a new outburst which is still in progress. Our image obtained with a global VLBI network shows the source to mainly consist of a core-jet like structure ending in diffuse emission region of low surface brightness located to the east of the core. We identify two new components as having been produced during the late 1980's. They are moving out with apparent superluminal motion in a viewing angle of greater-than-or-similar-to 10-degrees at a distance of less-than-or-similar-to 2 mas from the core. The core includes another new component, but our resolution is just sufficient to resolve out this component from the core at our epoch of observation. We suggest that the weak emission region is caused by an older component reaching the point at which the Doppler boosting is at its maximum and that the long time scale flux variation are due to successive events when evolved components reach that point.

• 334.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
The radio fine structure of the BL Lacertae object 0735 + 1781991In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 243, no 2, p. 328-332Article in journal (Refereed)

The BL Lacertae object 0735 + 178 has been mapped with global VLBI arrays at four epochs from 1979 to 1983. The hybrid maps presented in this paper show a complex structure with a component separating from the core with an apparent transverse velocity of almost-equal-to 7.9 c. We suggest a model in which new components are born in the core during an outburst, initially move away towards northeast and then at a distance of almost-equal-to 4.2 mas turn towards the southeast. At this point, the component does not show any discernible motion away from the core. We suggest that the jet curls towards the south and towards the observer and at this point has its minimum viewing angle, with maximum boosting and minimum apparent velocity. We associate the outburst of 1989 with the event when a superluminally moving component reaches this point.

• 335.
Industrihampa -hinder och drivkrafter för en utökad och kommersiell odling i Sverige2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis

Klimatförändringarna är en av vår tids största miljöproblem. Kött är det livsmedel som ger störst klimatpåverkan då ca 70 procent av de grödor som odlas används som djurfoder och idisslande djur släpper ut metan. Nästan en femtedel av de globala utsläppen av växthusgaser kommer från animalieproduktion. Betesdjur är dock avgörande för att nå de nationella miljömålen ”Ett rikt odlingslandskap” och ”Ett rikt växt- och djurliv”. Industrihampa är en gröda som kan användas som proteinfodertillskott och för att minska metangasbildningen under matspjälkningsprocessen hos idisslare. Hampan har också stora möjligheter att bidra positivt till att nå ett flertal av de andra nationella miljömålen då den kan ersätta fossila råvaror inom energi, bygg- och tillverkningsindustrin samt minska behovet av mineralgödsel i jordbruket. Syftet med detta examensarbete är att undersöka vilka hinder och drivkrafter som finns för en utökad och kommersiell hampaproduktion i Sverige. Genom att även undersöka om odling och användning av industrihampa ur ett kretsloppsperspektiv kan vara en del av lösningen i att bromsa klimatförändringarna, avser arbetet att förmedla kunskap om hur industrihampa kan minska klimatpåverkan från köttdjursuppfödning i Sverige och bidra till uppfyllandet av flera nationella miljömål. En litteraturstudie har gjorts för att få en djupare kunskap om problematiken kring klimatförändringar kopplat till lantbruk och köttdjursuppfödning samt för att bättre förstå hur industrihampa skulle kunna motverka detta. Intervjuer har utförts med hampaodlare, andra lantbrukare, intresseorganisationer och myndigheter för att samla in data om orsakerna till att odlingen av hampa i Sverige är så begränsad. Resultaten visar att hinder för en utökad och kommersiell odling är låg kunskap om hampan och dess egenskaper, dyrt utsäde, brist på lämpliga maskiner och en lagstiftning som ger utrymme för bred tolkning som narkotika och läkemedelskopplade tolkningar. Drivkrafter för ökad hampaodling är bland annat att grödan är mycket intressant och har stor potential att användas som råvara inom ett brett användningsområde. Den har god konkurrens mot ogräs och den är bra för miljön då den kan sanera mark som är förorenad av tungmetaller samt kan ersätta fossila material i tillverkningsindustrin och bomull i textilindustrin. Studien drar genom litteraturstudien slutsatsen att odling och användning av hampa i teorin har goda förutsättningar att bidra till att nå elva av sexton nationella miljömål. Drivkrafter för en ökad odling är en nyfikenhet på grödan, hampans potential att ut ett miljöperspektiv ersätta sämre råvaror och material samt konkurrensförmågan mot ogräs och minskat behov av växtskyddsmedel. Dock framkommer det ett flertal aspekter i intervjustudien som visar att i praktiken finns hinder som påverkar och hämmar en utökad och kommersiell odling av hampa, och därmed även möjligheten att bidra till att nå miljömålen. Lagstiftningen behöver förtydligas både för odlare samt myndigheter för att undvika osäkerhet och tolkningsproblem kring industrihampa kontra droghampa. Kunskapen om odling och användning av hampan behöver öka samt spridas. Större efterfrågan på hampa som råvara behövs. Här ligger ett stort ansvar på Sveriges regering och tillverkningsindustrin att lyfta fram grödan som ett alternativ.

• 336.
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
Handover in IEEE 802.11p-based delay-sensitive vehicle-to-infrastructure communication2009Report (Other academic)

Based on communication and cooperation between vehicles and roadside infrastructure, Intelligent Transport Systems (ITS) safety applications offer great potential to avoid traffic accidents or at least reduce their impact. As these applications usually are delay-sensitive, the delay introduced by waiting for access to the wireless communication channel should both be reduced and provided with an upper bound. The proposed IEEE 802.11p standard for short to medium range vehicular communication does not offer these guarantees. In previous work, we presented a MAC (Medium Access Control) enhancement supporting delay-sensitive, safety-critical V2I (Vehicle-to-Infrastructure) applications. Since the proposed enhancement requires a deterministic and fast mechanism to associate a vehicle to a roadside unit (RSU) so that it can be integrated into the centralized polling schedule, we now target the handover and connection setup between a vehicle and an RSU. Although the first connection setup with an RSU still underlies the randomness of the original 802.11p MAC method, we provide a deterministic solution to further enhance the handover procedures by introducing a fast, proactive handover mechanism. We show that the overhead of our solution is limited and still allows our MAC protocol to support safety-critical V2I applications in a densely trafficked highway scenario.

• 337.
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
Position-based data traffic prioritization in safety-critical, real-time vehicle-to-infrastructure communication2009In: IEEE International Conference on Communications Workshops, 2009. ICC Workshops 2009 / [ed] IEEE, Piscataway, N.J.: IEEE Press, 2009, p. 205-210Conference paper (Refereed)

Future active-safety applications in vehicular networks rely heavily on the support for real-time inter-vehicle communication. The Medium Access Control (MAC) mechanism proposed for the upcoming IEEE 802.11p standard intended for Intelligent Transport Systems (ITS) applications does not offer deterministic real-time support, i.e., the channel access delay is not upper bounded. We therefore propose a vehicle-to-infrastructure (V2I) communication solution extending IEEE 802.11p, by introducing a collision-free MAC phase with an enhanced prioritization mechanism based on vehicle positions and the overall road traffic density. A road side unit using a polling mechanism is then able to provide real-time support such that it can guarantee collision-free channel access within its transmission range. Part of the bandwidth remains unchanged such that best-effort services like ongoing vehicle-to-vehicle (V2V) applications may continue. Our solution guarantees that all communication deadlines of the V2I applications are met, while minimizing the required length of the collision-free phase. This in turn maximizes the amount of bandwidth available for best-effort services and ongoing V2V applications. The position-based prioritization mechanism further improves the throughput of both real-time and best-effort data traffic by focusing the communication resources to the most hazardous areas. The concept is evaluated analytically based on a realistic task set from a V2I merge assistance scenario.

• 338.
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
A fibre-optic AWG-based real-time network for high-performance embedded computing2004Conference paper (Refereed)

In this paper, an architecture and a Medium Access Control (MAC) protocol for a multiwavelength optical communication network, applicable in short range communication systems like System Area Networks (SANs), are proposed. The main focus lies on guaranteed support for hard and soft real-time traffic. The network is based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its center. Traffic scheduling is centralized in one node (residing together with the AWG in a hub), which communicates through a physical control channel. The AWG’s property of spatial wavelength reuse and the combination of fixedtuned and tunable transceivers in the nodes enable simultaneous control and data transmission. A case study with defined real-time communication requirements in the field of Radar Signal Processing (RSP) was carried out and indicates that the proposed system is very suitable for this kind of application.

• 339.
Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
Data age based MAC scheme for fast and reliable communication within and between platoons of vehicles2016In: International Conference on Wireless and Mobile Computing, Networking and Communications, Piscataway: IEEE, 2016Conference paper (Refereed)

Heavy vehicles driving as platoon with highly reduced inter-vehicle gaps has shown considerable fuel saving potential, but put high timing and reliability requirements on the underlying control data exchange. The recently standardized IEEE 802.11p protocol suite for Vehicular Ad-Hoc Networks (VANETs) and its message types do neither support the demands of a platooning application nor take advantage of its properties. We therefore propose a framework for centralized channel access with retransmission capabilities for safety critical control data exchange based on the data age of earlier received messages, DA-RE (Data Age based REtransmission scheme). A simulation comparison to the 802.11p random access Medium Access Control (MAC) protocol shows that the intelligent assignment of retransmission opportunities considerably improves the reliability of platooning control data. We also propose a power control based scheme for early platoon detection allowing several platoons to temporarily share a channel and show that the safe and reliable operation of their vehicles is not compromised. © 2016 IEEE.

• 340.
Halmstad University, School of Education, Humanities and Social Science.
Halmstad University, School of Education, Humanities and Social Science.
En litteraturstudie av elevers lärande inom geometri i grundskolan med stöd av digitala verktyg2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis

Based on our experiences, literature and research literature, some teachers experience that certain parts of the subject geometry are difficult to teach about. They also experience that the teaching aids are not sufficient enough for developing their teaching. The research we mentioned is that some students do not get enough teaching to be able to conduct mathematical conversations about geometric objects, to relate the objects to each other and insert them into different contexts. Some students also have difficulties in problematizing and constructing geometric objects. With dynamic geometry and the use of digital tools, students can have more time to develop their understanding of geometric objects being constructed. The aim of this literature study is to compile how research describes teaching the subject geometry with the support of digital tools, and more specifically, to answer the question: How can teaching in geometry, according to research, be developed by using digital tools? To answer the question and achieve the aim of the study, we have systematically presented, analyzed and compiled scientific studies on the use of digital tools in the teaching of geometry. Our results show that digital tools enable exploratory working methods, social interaction and increase some students' motivation and commitment, and that some students van Hiele-level in geometric thinking increase while using digital tools. Finally, we discuss didactic implications such as that digital tools contribute to an exploratory approach and increase students' involvement and motivation. Another implication is that all schools do not have access to digital tools and that technical problems can arise when using these, which can lead to a reduction of teaching time. As a proposal for further research, we see an opportunity to look at how the creation and display of video clips affect pupils' learning in geometry.

• 341.
University of Konstanz, Konstanz, Germany.
University of Konstanz, Konstanz, Germany. Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
(De-)Composing Causality in Labeled Transition Systems2016In: 1st Workshop on Causal Reasoning for Embedded and safety-critical Systems Technologies (CREST’16) / [ed] Gregor Gössler & Oleg Sokolsky, Open Publishing Association , 2016, Vol. 224, p. 10-24Conference paper (Refereed)

In this paper we introduce a notion of counterfactual causality in the Halpern and Pearl sense that is compositional with respect to the interleaving of transition systems. The formal framework for reasoning on what caused the violation of a safety property is established in the context of labeled transition systems and Hennessy Milner logic. The compositionality results are devised for non-communicating systems.

• 342.
DiLab i Lund AB.
AstraZeneca R and D. Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
A biometric approach to laboratory rodent identification2007In: Lab animal, ISSN 0093-7355, E-ISSN 1548-4475, Vol. 36, no 3, p. 36-40Article in journal (Refereed)

Individual identification of laboratory rodents typically involves invasive methods, such as tattoos, ear clips, and implanted transponders. Beyond the ethical dilemmas they may present, these methods may cause pain or distress that confounds research results. The authors describe a prototype device for biometric identification of laboratory rodents that would allow researchers to identify rodents without the complications of other methods. The device, which uses the rodent's ear blood vessel pattern as the identifier, is fast, automatic, noninvasive, and painless.

• 343.
Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden.
Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden.
Raising the superconducting Tc of gallium: In situ characterization of the transformation of α -Ga into β -Ga2018In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, no 18, article id 184517Article in journal (Refereed)

Gallium (Ga) displays several metastable phases. Superconductivity is strongly enhanced in the metastable β-Ga with a critical temperature Tc=6.04(5)K, while stable α-Ga has a much lower Tc<1.2K. Here we use a membrane-based nanocalorimeter to initiate the transition from α-Ga to β-Ga on demand, as well as study the specific heat of the two phases on one and the same sample. The in situ transformation is initiated by bringing the temperature to about 10K above the melting temperature of α-Ga. After such treatment, the liquid supercools down to 232K, where β-Ga solidifies. We find that β-Ga is a strong-coupling type-I superconductor with Δ(0)/kBTc=2.00(5) and a Sommerfeld coefficient γn=1.53(4)mJ/molK2, 2.55 times higher than that in the α phase. The results allow a detailed comparison of fundamental thermodynamic properties between the two phases. © 2018 American Physical Society.

• 344.
Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Biomechanics and Biomedicine.
Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Biomechanics and Biomedicine.
Examining muscle activation for Hang Clean and three different TRX Power Exercises: A validation study2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

Background: Resistance training has proven to increase athletic performance, traditionally barbell training and Olympic Lifting have been used for this purpose. Sling training has recently been developed as a complement or substitution to traditional resistance training. Research has shown an increase in sport specific athletic performance and core stability with sling training. TRX Suspension Trainer is a newly developed sling training tool and to date no independent research has been done with the TRX. Purpose: To examine and compare muscle activation using TRX and the Olympic Lifting movement Hang Clean. Methods: 32 senior high school male soccer players participated in the study. Surface electromyographic (sEMG) data were collected on mm.erector spinae (back), m.gluteus maximus (glutes), m.vastus lateralis (quadriceps), m.semitendinosus (hamstrings) and m.gastrocnemius caput laterale (calf). Surface EMG data was collected when the subjects performed five different exercises, Hang Clean, TRX Squat Jump, TRX Front Squat and TRX Power Pull. In addition a Squat Jump was used as reference. Results: A similar muscle activation was found between Hang Clean (674 µV), TRX Squat Jump (684 µV) and TRX Front Squat (691 µV). TRX Power Pull showed the highest activation for mm.erector spinae and m.gluteus maximus but the lowest when comparing total muscle activation for all measured muscles. Conclusion: The similar amount of muscular activation for Hang Clean, TRX Squat Jump and TRX Front Squat indicates that the TRX Suspension Trainer can be used as a complement, for experienced athletes, or a substitution, for novice athletes, to traditional strength training. Coaches and athletic trainers should acknowledge the need and the importance of resistance training for athletic performance.

• 345.
Genetics of Microorganisms, University of Liège, Liège, Belgium.
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba. Campus de Rabanalles, Edif. Severo Ochoa, Córdoba, Spain. Genetics of Microorganisms, University of Liège, Liège, Belgium. Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Plant Cell Biology: Energy transduction in plant cells. Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Colonia Copilco-Universidad, Delegación Coyoacán, México D.F., Mexico.
Oxidative Phosphorylation: Building blocks and related components2009In: The Chlamydomonas Sourcebook: Organellar and Metabolic Processes, Volume 2, Second Edition / [ed] Elizabeth H. Harris, David B. Stern & George B. Witman, Oxford: Academic Press, 2009, p. 469-502Chapter in book (Other academic)

This chapter summarizes the knowledge of the oxidative phosphorylation (OXPHOS) constituents of Chlamydomonas and of the components involved in their biogenesis and addresses alternate dehydrogenases and oxidases which are particular to photosynthetic organisms, and several other mitochondrial components related to OXPHOS. Reference to the components of Polytomella sp., a colorless alga closely related to Chlamydomonas is clearly made. The main complexes involved in electron transport seem to share a similar number of subunits, and many of the algal polypeptides have plant homologues. Some differences are apparent, such as the presence of a fragmented COX2 subunit, which seems to be unique to chlorophyte algae. OXPHOS is defined as an electron transfer chain driven by substrate oxidation that is coupled to the synthesis of ATP through an electrochemical transmembrane gradient. The characterization of Arabidopsis mitochondrial components through proteomic approaches has advanced significantly. As a unicellular organism, Chlamydomonas offers the unique opportunity to study organelle-organelle interactions, particularly between mitochondria and chloroplasts. It has become evident that crosstalk between these organelles takes place, mainly through intracellular metabolite pools. © 2009 Elsevier Inc. All rights reserved.

• 346.
Correlation between upper body strength and sprint performance in the four competitive strokes of swimming2015Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis

BACKGROUND: There are four different strokes in competitive swimming; butterfly (BU), backstroke (BA), breaststroke (BR) and freestyle (FR), all strokes demanding different skills from the athlete. Numerous studies have examined the relationship between upper body strength and FR swimming performance while the other strokes are scarcely investigated. AIM: The aim of this study was to investigate the strength of the correlation between absolute upper body maximum strength, examined by the latpull, and swimming velocity, evaluated by swim sprint performance time, in the four different strokes in sprint swimming. METHODS: Fifteen elite male swimmers, age 14- 29 years, were included in the study. The study had an experimental design where the subjects performed a swim test including 50 meters of each swimming stroke in an indoor 25-meter pool. A maximum strength test was performed 12-72 hours after the swim test, using the latpull as an upper body strength measure. The Pearson correlation coefficient was used to analyse the strength of the correlation between swimming performance in the four different strokes and absolute upper body maximum strength. RESULTS: The strokes displaying the strongest correlations between swimming performance and maximum strength were FR (r=0.49, p=0.065), BU (r=0.48, p=0.073) and BA (r=0.46, p=0.081). BR presented the weakest correlation (r=0.11, p=0.69). CONCLUSIONS: There is a moderate correlation between upper body maximum strength and FR, BA and BU swimming performance and a weak correlation between upper body maximum strength and BR swimming performance. The transferability to other groups can be questioned since the results were not statistically significant. Further research is emphasized examining a larger number of subjects specialized in a certain stroke to develop the understanding of resistance training’s influence on swimming performance in the four competitive strokes of swimming.

• 347.
Animaliskt matsvinn från tre olika steg i livsmedelskedjan2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

• 348.
Halmstad University, School of Teacher Education (LUT).
Halmstad University, School of Teacher Education (LUT).
Hållbar utveckling inom ekologi: Fyra verksamma förskolepedagogers uppfattningar2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

Hållbar utveckling inom ekologi, en studie gjord utifrån två kvalitativa gruppintervjuer på två slumpmässigt utvalda förskolor, där syftet är att belysa variationen av de fyra deltagande pedagogernas uppfattningar kring hållbar utveckling inom ekologi. Ett problem är att det enligt forskningen finns en osäkerhet i att undervisa naturvetenskap bland pedagoger. De är frågetecken i vad och hur pedagogerna ska undervisa. Det som studien resulterat i är exempel på vad pedagoger i förskolan har för uppfattningar om vad hållbar utveckling inom ekologi är och hur de ser på sitt arbete i ämnet.

Eftersom studien fokuserar på pedagogernas uppfattningar är den fenomenografisk, men tar även avstamp i hermeneutiken eftersom den utgår från vår förförståelse och tidigare erfarenhet om problemet med ämnet.

Resultatet av studien visar vad de deltagande pedagogerna har för uppfattningar om vad hållbar utveckling inom ekologi är. Enligt pedagogerna är hållbar utveckling inom ekologi ett prioriterat och viktigt ämne, som barnen ska få ta del av redan i tidig ålder. De handlar om att värna om vår jord och att ge barnen möjligheter att vistas i och uppleva naturen.

• 349.
Extreme weather affects the peregrine falcon’s (Falco peregrinus tundrius) breeding success on South Greenland2017Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis

In order to understand the effects of climate change on the peregrine’s future prospects, we investigated the relationship between weather variables (extreme weather) and breeding success parameters for the peregrine in South Greenland.

We defined two variables for comparison with weather data: young per known territory and nest success, i.e. proportion of known sites producing young, for each monitored year (N = 33). Weather data were obtained from two weather stations in the study area. From the weather data four extreme predictor variables were calculated: extreme low temperature, extreme precipitation, consecutive rainy days and total days with extreme weather. Peregrine breeding success (both parameters) was correlated negatively with number of days with extreme weather; the strongest correlation found was between total days in the season with extreme weather and breeding success. Low temperature and total days with extreme weather during the pre-laying and incubation period were also significantly negatively correlated with breeding success. Thereby, extreme weather is an important factor in explaining the peregrine’s breeding success. However, other factors also influence the breeding success, in the last few years there has been a strong downward trend but not an increase of extreme weather events during the same period.

• 350.
Halmstad University, School of Business, Engineering and Science. www.vandrefalk.dk, Stockholm, Sweden. Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Roskilde University Library, Roskilde, Denmark.
Extreme weather affects Peregrine Falcon (Falco peregrinus tundrius) breeding success in South Greenland2018In: Ornis Hungarica, ISSN 1215-1610, Vol. 26, no 2, p. 38-50Article in journal (Refereed)

In order to better understand the potential effects of climate change on the Peregrine Falcon, we investigated the relationship between extreme weather events and Peregrines’ breeding success in South Greenland. We defined three variables – number of days with extremely low temperatures, extreme precipitation, consecutive rainy days – and an additive variable, total days with extreme weather, and tested their relationship with Peregrines’ breeding success (measured as young per site and nest success) over a 33 year study period. Breeding success was negatively influenced by the number of days with extreme weather and extremely low temperature. The strongest relationship found was total days with extreme weather in the entire breeding season, which explained 22% and 27% of the variation in nest success and young per site, respectively. The number of days with extreme weather in our study related to fluctuations in the North Atlantic Oscillation (NAO). Thus, with a strengthening of the NAO, linked to climate change, more extreme weather may occur in the Arctic and induce increased variation in Peregrines’ breeding success. Our data did not allow us to pinpoint when in the breeding cycle inclement weather was particularly harmful, and we recommend finer-scale research (e.g. automated nest cameras) to better monitor the species-specific effects of rapidly changing climate.

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