| 631. |
- Persson, Anders
(författare)
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Lektioner i 7F
- 1986
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Ingår i: Helsingborgs Dagblad. - 1103-9388. ; :1986-10-20
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Recension (populärvet., debatt m.m.)abstract
- Allan Friis tecknar bilden av en absurd institution som hos många elever förmår skapa motvilja till och med mot något så positivt som kunskap.
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| 632. |
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| 633. |
- Persson, Anders, et al.
(författare)
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Linking patch-use behavior, resource density, and growth expectations in fish
- 2006
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Ingår i: Ecology. - 0012-9658. ; 87:8, s. 1953-1959
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Tidskriftsartikel (refereegranskat)abstract
- Optimality theory rests on the assumptions that short-term foraging decisions are driven by variation in environmental quality, and that these decisions have important implications for long-term fitness. These assumptions, however, are rarely tested in a field setting. We linked behavioral foraging decisions in food patches with measures of environmental quality covering larger spatial (resource density) or temporal (growth parameters) scales. In 10 lakes, we measured the food density at which benthic fish give up foraging in experimental food patches (giving-up density, GUD), quantified the biomass of benthic invertebrates, and calculated the maximum individual size (L-infinity) of bream (Abramis brama L.), a typical benthivore in these lakes. We found positive relationships between resource density and both GUD and L-infinity, and a positive relationship between L-infinity and GUD. Prey characterized as vulnerable to predation contributed most to the relationships between resource density and either GUD or L-infinity. A path analysis showed that resource density and L-infinity directly explained 54% and 28%, respectively, of the variation in GUD, whereas 86% of the variation in L-infinity was explained by resource density, with mostly indirect contribution from GUD. We conclude that the short-term foraging behavior of benthivores matched our expectations based on optimality theory by being positively linked to variables on environmental quality operating at both a larger spatial scale and a longer temporal scale.
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| 634. |
- Persson, Anders, 1982-, et al.
(författare)
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Low-frequency noise in planar Hall effect bridge sensors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a knee frequency of around 400 Hz. The 1/f-like excess noise can be described by the phenomenological Hooge equation with a Hooge parameter of gH=0.016. The detectivity is shown to depend on the total length, width and thickness of the bridge branches. Increasing the total length by a factor of 10 improves the detectivity by a factor of 101/2. Moreover, the detectivity is shown to depend on the amplitude of the applied magnetic field, revealing a magnetic origin to part of the 1/f noise.
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| 635. |
- Persson, Anders, 1982-, et al.
(författare)
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Low-frequency noise in planar Hall effect bridge sensors
- 2011
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Ingår i: Sensors and Actuators A-Physical. - : Elsevier. - 0924-4247 .- 1873-3069. ; 171:2, s. 212-218
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Tidskriftsartikel (refereegranskat)abstract
- The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a knee frequency of around 400 Hz. The 1/f-like excess noise can be described by the phenomenological Hooge equation with a Hooge parameter of γH = 0.016. The detectivity is shown to depend on the total length, width and thickness of the bridge branches. The detectivity is improved by the square root of the length increase. Moreover, the detectivity is shown to depend on the amplitude of the applied magnetic field, revealing a magnetic origin to part of the 1/f noise.
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| 636. |
- Persson, Anders, 1982-, et al.
(författare)
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Low-frequency picotesla field detection with planar Hall effect bridge sensors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The applicability of miniaturized magnetic field sensors are being explored in several fields of magnetic field detection, due to their integratability, low mass, and potentially low cost. In this respect, different thin-film technologies, especially those employing magnetoresistance, show great potential, being compatible with micro- and nanotechnology batch processing. For low-frequency magnetic field detection, sensors based on the planar Hall effect, especially planar Hall effect bridge (PHEB) sensors, show promising performance given their inherent low-field linearity, limited hysteresis and moderate noise figure. In this work, the applicability of such PHEB sensors to different areas is investigated. An analytical model was constructed, to estimate the performance of an arbitrary PHEB in terms of e.g. sensitivity and detectivity. The model incorporates a number of approximations and, to validate the results, modelled data is compared to measurements on actual PHEBs. It is concluded that the model slightly underestimated the detectivity, especially at low frequencies and when demagnetizing effects becomes apparent. The model is also sensitive to fabrication process induced variations of the material parameters of the sensors. Nevertheless, accounting for these discrepancies, the modelled data is typically within 10% from the experimental data and the model can be used to estimate the performance of a particular PHEB design. The model is also used to establish a design process for optimizing a PHEB to a particular set of requirements on the bandwidth, detectivity, compliance voltage and amplified signal-to-noise ratio. By applying this design process, the size, sensitivity, resistance, bias current and power consumption of the PHEB can be calculated. The model shows that PHEBs are applicable to several different science areas including archaeological surveying, satellite attitude determination, scientific space missions, and magnetic bead detection in lab-on-a-chip applications.
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| 637. |
- Persson, Anders, 1958-
(författare)
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Lucky Strike - cancerlobbyistens guldkalv
- 2002
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Ingår i: Dagens forskning: : tidning för vetenskap och kultur, teknik och samhälle. ; , s. 14-14
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 638. |
- Persson, Anders, et al.
(författare)
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Lyssnande på offentliga platser
- 2011
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Ingår i: Många möjliga metoder. - 9789144074221 ; , s. 237-251
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Bokkapitel (refereegranskat)
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| 639. |
- Persson, Anders, et al.
(författare)
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Lytting på offentlig sted
- 2011
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Ingår i: Mange ulike metoder. - 9788205413917 ; , s. 235-250
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Bokkapitel (refereegranskat)
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| 640. |
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