| 1. |
- Aharonian, Felix, et al.
(författare)
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Hitomi X-ray studies of giant radio pulses from the Crab pulsar
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2-300 keV band and the Kashima NICT radio telescope in the 1.4-1.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 sigma fluctuations of the X-ray fluxes at the pulse peaks, and the 3 sigma upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2-300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and 70-300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) x 10(-11) erg cm(-2), respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magneto-sphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a > 0.02% brightening of the pulse-peak flux under such conditions.
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| 2. |
- Hansen, Dan Witzner, et al.
(författare)
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Discussion and Future Directions for Eye Tracker Development
- 2012
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Ingår i: Gaze Interaction and Applications of Eye Tracking : Advances in Assistive Technologies - Advances in Assistive Technologies. - : IGI Global. - 9781613500989 - 161350098X ; , s. 359-363
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Bokkapitel (refereegranskat)abstract
- Eye and gaze tracking have a long history but there is still plenty of room for further development. In this concluding chapter for Section 6, we consider future perspectives for the development of eye and gaze tracking.
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| 3. |
- Hansen, Dan Witzner, et al.
(författare)
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Introduction to Eye and Gaze Trackers
- 2012
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Ingår i: Gaze Interaction and Applications of Eye Tracking. - : IGI Global. - 9781613500989 ; , s. 288-295
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Bokkapitel (refereegranskat)abstract
- In the previous chapters of the book, you will have seen multiple applications for using (and the benefits of using) a gaze tracker. In this chapter, you will be given more insight into how an eye tracker operates. Not only can this aid in understanding the eye tracker better, it also gives important information about how future applications might improve on current ones, by using more of the information available from the eye tracker: as we shall see, an eye tracker can often provide you with more information than just coordinates on a screen. This chapter gives an overview of the components of an eye tracker and introduces basics of gaze modelling. It helps in understanding the following chapters which each provide some details of how to build an eye tracker. This section has technical content, but it is our hope that also readers not particularly interested in the details of eye and gaze trackers will gain some useful insights.
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| 4. |
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| 5. |
- Zeichner, Sarah S., et al.
(författare)
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Polycyclic aromatic hydrocarbons in samples of Ryugu formed in the interstellar medium
- 2023
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 382:6677, s. 1411-1415
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Tidskriftsartikel (refereegranskat)abstract
- Polycyclic aromatic hydrocarbons (PAHs) contain less than or similar to 20% of the carbon in the interstellar medium. They are potentially produced in circumstellar environments (at temperatures greater than or similar to 1000 kelvin), by (similar to 10 kelvin) interstellar clouds, or by processing of carbon-rich dust grains. We report isotopic properties of PAHs extracted from samples of the asteroid Ryugu and the meteorite Murchison. The doubly-C-13 substituted compositions (Delta 2x(13)C values) of the PAHs naphthalene, fluoranthene, and pyrene are 9 to 51 parts per thousand higher than values expected for a stochastic distribution of isotopes. The Delta 2x(13)C values are higher than expected if the PAHs formed in a circumstellar environment, but consistent with formation in the interstellar medium. By contrast, the PAHs phenanthrene and anthracene in Ryugu samples have Delta 2x(13)C values consistent with formation by higher-temperature reactions.
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| 6. |
- Mulvey, Fiona, et al.
(författare)
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Eye Anatomy, Eye Movements and Vision
- 2012
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Ingår i: Gaze Interaction and Applications of Eye Tracking. - : IGI Global. - 9781613500989 ; , s. 10-20
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Bokkapitel (refereegranskat)abstract
- This chapter introduces the basics of eye anatomy, eye movements and vision. It will explain the concepts behind human vision sufficiently for the reader to understand later chapters in the book on human perception and attention, and their relationship to (and potential measurement with) eye movements. We will first describe the path of light from the environment through the structures of the eye and on to the brain, as an introduction to the physiology of vision. We will then describe the image registered by the eye, and the types of movements the eye makes in order to perceive the environment as a cogent whole. This chapter explains how eye movements can be thought of as the interface between the visual world and the brain, and why eye movement data can be analysed not only in terms of the environment, or what is looked at, but also in terms of the brain, or subjective cognitive and emotional states. These two aspects broadly define the scope and applicability of eye movements technology in research and in human computer interaction in later sections of the book.
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| 7. |
- Mulvey, Fiona, et al.
(författare)
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Eye Movements and Attention
- 2012
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Ingår i: Gaze Interaction and Applications of Eye Tracking. - : IGI Global. - 9781613500989 ; , s. 129-152
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Bokkapitel (refereegranskat)abstract
- When it comes to measuring attention, or quantifying it in any way, it is not easy to pin down what exactly we measure. Advances in technology have enabled the construction of complex models of certain aspects of attention and identified many of the structures and factors involved in the changing nature of attention. In this chapter, we will go with a working definition of attention as the concentration or focusing of mental effort on sensory or internal mental events. In terms of eye movements, we are mainly concerned with visual attention, pertaining to events and external stimuli in the environment, but not exclusively so. Eye movements may also offer an opportunity to measure internal or subjective events and states. This chapter will look at what might be possible beyond direct, point and click gaze control, in inferring subjective states. The aim is to identify and explain those measures from cognitive psychology which are most promising in terms of future technologies for gaze based human computer interaction.
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| 8. |
- Mulvey, Fiona, et al.
(författare)
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Safety Issues and Infrared Light
- 2012
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Ingår i: Gaze Interaction and Applications of Eye Tracking. - : IGI Global. - 9781613500989 ; , s. 336-358
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Bokkapitel (refereegranskat)abstract
- Infrared light is the most common choice for illumination of the eye in current eye trackers, usually produced via IR light-emitting diodes (LEDs). This chapter provides an overview of the potential hazards of over-exposure to infrared light, the safety standards currently in place, configurations and lighting conditions employed by various eye tracking systems, the basics of measurement of IR light sources in eye trackers, and special considerations associated with continuous exposure in the case of gaze control for communication and disabled users. It should be emphasised that any eye tracker intended for production should undergo testing by qualified professionals at a recognised test house, in a controlled laboratory setting. However, some knowledge of the measurement procedures and issues involved should be useful to designers and users of eye tracking systems.
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| 9. |
- Rhind, Nicholas, et al.
(författare)
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Comparative Functional Genomics of the Fission Yeasts
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 332:6032, s. 930-936
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Tidskriftsartikel (refereegranskat)abstract
- The fission yeast clade-comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus, and S. japonicus-occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, which suggests a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the budding yeast of Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade.
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| 10. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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