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- Nygren, Martin, et al.
(författare)
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Identification of 2,3,7,8-substituted polychlorinated dioxins and dibenzofurans in environmental and human samples
- 1986. - 1
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Ingår i: Chlorinated dioxins and dibenzofurans in perspective. - Boca Raton : CRC Press. - 9781315891545 - 9781351070645 ; , s. 17-34
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are two series of tricyclic, almost planar aromatic compounds that exhibit very similar physical, chemical, and biological properties. The human exposure to PCDDs and PCDFs by milk consumption is not negligible. Detection levels in ecological and human samples should be orders of magnitude below the usual detection levels obtained in pesticide analyses. One objective of the study is to identify background levels of PCDDs and PCDFs in these samples, especially those of human origin. The spectrum of toxic effects is species dependent but for humans they include chloracne and porphyria cutane tarda and for other animals edema, thymic atrophy, teratogenicity, liver lesions and a slow wasting syndrome followed by death. It is evident that it is of particular importance to identify the ultimate source or sources of the toxic 2,3,7,8-substituted PCDDs and PCDFs found as background constituents in the environmental and human samples, especially the samples of mother's milk, which are of toxicological interest.
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| 7. |
- Bengtsson, Daniel, et al.
(författare)
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Zipper performance when mixing ADSL and VDSL in terms of reach and capacity
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this contribution we have examined how the maximum reach vary at different bit rates on a VDSL system, when different numbers of ADSL and VDSL systems share the same binder. In this context it is concluded that when using the Zipper duplex scheme, VDSL can coexist with ADSL in the same binder without a significant degradation in reach. Further, it is shown that the Zipper duplex scheme secure that ADSL is not disturbed by NEXT from VDSL The Zipper performance has also been compared with both a TDD proposal and a FDD proposal. The results from this comparison shows that Zipper outperforms FDD and TDD in terms of extended reach at all studied mixes of ADSL and VDSL sharing the same binder. For example with a moderate number (5) of ADSL disturbers, the Zipper reach is 150 meters longer than for TDD, and is 350 meters longer than for FDD when studying the medium range asymmetrical bit rate (26:3.2 Mbps).
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| 8. |
- Biermann, F., et al.
(författare)
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Navigating the Anthropocene: Improving Earth System Governance
- 2012
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 335:6074, s. 1306-1307
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The United Nations conference in Rio de Janeiro in June is an important opportunity to improve the institutional framework for sustainable development.
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- Boisvert, Catherine Anne, 1978-
(författare)
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The Origin of Tetrapod Limbs and Girdles: Fossil and Developmental Evidence
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Around 375 million years ago, the first tetrapods appeared, marking one of the most important events in vertebrate evolutionary history. The fin to limb transition saw the appearance of fingers and a weight bearing pelvic girdle. While very little research has been done on the evolution of the tetrapod pelvic girdle, a fair amount has been done on the origins of fingers but some aspects remained controversial. A combination of palaeontology, developmental biology and comparative morphology was therefore used in this thesis to better understand the fin to limb transition. The pectoral fin of Panderichthys, a sarcopterygian fish closely related to tetrapods was CT-scanned and modeled in three dimensions and its pelvic girdle and fin were examined with traditional techniques. This information from the fossil record was integrated with comparisons of the development of the Australian lungfish, Neoceratodus forsteri, our closest living fish relative and the axolotl (Ambystoma mexicanum), a salamander representing well the condition of early tetrapods. Development of bone and cartilage was studied through clearing and staining and development of skeletal muscles through immunostaining. In situ hybridizations were performed on the lungfish to study the expression of Hoxd13, associated with the formation of digits in tetrapods. This work shows that the late expression phase of Hoxd13 is present in Neoceratodus and is associated with the formation of radials. Redescription of the pectoral fin of Panderichthys reveals that distal radials are present, which, in addition to other information, lead us to conclude that digits are not novelties in tetrapods but rather have evolved from the distal radials present in the fins of all sarcopterygian fish. The earliest tetrapods lack a full set of wrist + carpals/ankle + tarsal bones. Here, we propose that this region of the limbs evolved after fingers and toes through an expansion of the region between the proximal limb bones and the digits. As for the pelvic girdle, it is very primitive in Panderichthys but comparison of its development in Neoceratodus and Ambystoma suggest that the ischium evolved through the posterior expansion of the pubis and the ilium, through an elongation of the iliac process already present in sarcopterygian fishes. The results of this thesis help to better understand the fin to limb transition and show that it is more gradual than previously believed.
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| 10. |
- Bryhn, Andreas, et al.
(författare)
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Fisk- och skaldjursbestånd i hav och sötvatten 2019 : Resursöversikt
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fisken i havet är en resurs som rör sig fritt över nationella gränser. EU har därför en gemensam fiskeripolitik (GFP). Många arter som är viktiga för Sverige regleras inte i GFP och förvaltas därför nationellt.Denna rapport syftar till att:beskriva utvecklingen av fiskeripolitikenförklara den nuvarande politikens mål och regelverk och dess relation till mål och regler på miljöområdetförklara politikens nationella genomförande och det nationella handlingsutrymmetexemplifiera hur Havs- och vattenmyndigheten arbetat med att reglera fisket.
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