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- Andersson, Ki, 1975-
(författare)
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Aspects of locomotor evolution in the Carnivora (Mammalia)
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, the shape of the distal humerus trochlea is analysed using landmark-based morphometrics and multivariate methods, with the aim of exploring locomotor evolution in carnivorans. Elbow joint morphology is used together with body size and craniodental morphology to characterize past and present carnivorans. Evolutionary implications are studied at the ordinal, familial, and species levels, testing specific hypotheses about scaling, morphological constraints, evolutionary trajectories, and potential for social pack-hunting behaviour. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and appears to scale similarly throughout the order Carnivora. A general predictive model for carnivoran bodymass is presented (a=0.601; b= 2.552; r2=0.952, SEE=0.136, p<0001, n=92), which removes the need for the investigator to actively choose between the diverging estimates that different predictors and their equations often produce. At the elbow joint, manual manipulation and locomotion appear to be conflicting functions, thus suggesting mutually exclusive lifestyles involving either forelimb grappling or pursuit. At large body sizes, carnivorans are distributed over a strongly dichotomised pattern (grappling or locomotion), a pattern coinciding with the postulated threshold in predator-prey size ratio at 21.5-25 kg. This pattern is compared to that of two carnivoran faunas from the Tertiary. In the Oligocene (33.7-23.8 Myr BP), the overall pattern is remarkably similar to that observed for extant Carnivora. In the Miocene (23.8-11.2 Myr BP) carnivores show a similarly dichotomised pattern as the Oligocene and Recent, although the whole pattern is shifted towards larger body sizes. This difference is suggested to be a reflection of the extraordinary species richness of browsing ungulates in the early Miocene of North America. Such an increase in prey spectrum would create a unique situation, in which large carnivores need not commit to a cursorial habitus in order to fill their nutritional requirements. Finally, the elbow joints and craniodental morphology (14 measurements) of fossil canids were examined with the aim of assessing the potential for pack-hunting in fossil canids. It is clear that small and large members of the Recent Caninae share similar craniodental morphologies. However, this pattern is not present in Borophaginae and Hesperocyoninae. In the latter, large representatives are characterized by being short-faced, with reduced anterior premolars and enlarged posterior premolars, thus approaching a “pantherine-like” craniodental configuration. These traits are interpreted as an adaptation for killing prey with canine bites. It is similarly determined that, unlike recent Caninae, all analyzed species of borophagines and hesperocyonines have retained the ability to supinate their forearms. It is therefore likely that manual manipulation was part of their hunting behaviour, thus removing an essential part of the argument for social pack-hunting in these forms, as the benefits of such a strategy become less obvious.
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- Betts, Marissa J, et al.
(författare)
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Integrated chronostratigraphy of the lower Cambrian Byrd Group, Transantarctic Mountains
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Antarctica and Australia were sutured together straddling the equator during the major pulse of animal biodiversification associated with the Cambrian radiation. However, lack of detailed systematic sampling of lower Cambrian sedimentary packages from Antarctica has significantly impeded precise age determination and correlation with other Cambrian paleocontinents, especially with other parts of East Gondwana. Here were present new, integrated biostratigraphic and chemostratigraphic (δ13C isotopes) data from three stratigraphic sections measured through autochthonous shallow water carbonates (including archaeocyath-microbial bioherms) from the lower Cambrian Byrd Group in the Transantarctic Mountains. Recovered shelly fossil assemblages (brachiopods, tommotiids, molluscs, trilobites) from the Holyoake and Churchill Ranges include conspecific taxa previously described from Hawker Group rocks in the Arrowie Basin of South Australia facilitating direct correlation with the upper Dailyatia odyssei biozone. Synchronous chemostratigraphic data capture a distinctive positive ?13C excursion in the Churchill Range interpreted as the global Mingxinsi Carbon Isotope Excursion (MICE) peak. A succeeding gradual negative ?13C excursion captured in the Churchill and Holyoake sections is interpreted as the global Archaeocyathid Extinction Carbon Isotope Excursion (AECE) event. There is no chemostratigraphic evidence for the large Redlichiid-Olenellid Extinction Carbon Isotope Excursion (ROECE) negative event that straddles and defines the Cambrian Stage 4 – Miaolingian boundary. Hence, the integrated faunal and new chemostratigraphic data presented herein strongly support a Cambrian Stage 4 age for the upper Shackleton Limestone – Holyoake Formation – Starshot Formation succession of the Byrd Group.
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- Bohgard, Mats, et al.
(författare)
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Fysikaliska faktorer
- 2008
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Ingår i: Arbete och teknik på människans villkor. - 9789173650373 ; , s. 191-307
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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- Bohgard, Mats, et al.
(författare)
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Physical Factors
- 2009
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Ingår i: Work and Technology on Human Terms. - 9789173650588 ; , s. 191-306
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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- Holmér, Gunnel, 1955-
(författare)
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Kosta glasbruk - en etnisk smältdegel? : Arbete och arbetskraftsinvandring 1943-1973
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingen fokuserar på arbetskraftsinvandringen till Kosta glasbruk under perioden 1943-1973. Den övergripande frågan är om svenskar och invandrare tilldelades likvärdiga arbetsuppgifter eller om diskriminering kopplad till arbetet förekommit. Vidare undersöks varför företaget rekryterade utländsk arbetskraft, vilka nationaliteter som var representerade, orsakerna bakom migrationen, invandrarnas kvalifikationer samt den lokala fackföreningens inställning till immigranterna. Studien bygger på arkivmaterial kompletterat med ett 40-tal intervjuer med såväl svenska som invandrade glasarbetare samt med tjänstemän.
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- Holmer, Helene, et al.
(författare)
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Fracture incidence in GH-deficient patients on complete hormone replacement including GH
- 2007
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431 .- 1523-4681. ; 22:12, s. 1842-1850
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Tidskriftsartikel (refereegranskat)abstract
- Fracture risk in GHD patients is not definitely established. Studying fracture incidence in 832 patients on GH therapy and 2581 matched population controls, we recorded a doubled fracture risk in CO GHD women, but a significantly lower fracture risk in AO GHD men. Introduction: The objective of this study was to evaluate fracture incidence in patients wilh confirmed growth hormone deficiency (GHD) on replacement therapy (including growth hormone [GH]) compared with population controls, while also taking potential confounders and effect modifiers into account. Materials and Methods: Eight hundred thirty-two patients with GHD and 2581 matched population controls answered a questionnaire about fractures and other background information. Incidence rate ratio (IRR) and 95% CI for first fracture were estimated. The median time on GH therapy for childhood onset (CO) GHD men and women was 15 and 12 yr, respectively, and 6 and 5 yr for adult onset (AO) GHD men and women, respectively. Results: A more than doubled risk (IRR, 2.29; 95% CI, 1.23-4.28) for nonosteoporotic fractures was recorded in women with CO GHD, whereas no risk increase was observed among CO GHD men (IRR. 0.61) and AO GHD women (IRR, 1.08). A significantly decreased incidence of fractures (IRR, 0.54; 95% CI 0.34-0.86) was recorded in AO GHD men. Conclusions: Increased fracture risk in CO GHD women can most likely be explained by interaction between oral estrogen and the GH-IGF-I axis. The adequate substitution rate of testosterone (90%) and GH (94%) may have resulted in significantly lower fracture risk in AO GHD men.
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- Holmer, Helene, et al.
(författare)
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Nonfatal stroke, cardiac disease, and diabetes mellitus in hypopituitary patients on hormone replacement including growth hormone
- 2007
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 92:9, s. 3560-3567
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Tidskriftsartikel (refereegranskat)abstract
- Context: The impact of long-term GH replacement on cerebrovascular and cardiovascular diseases and diabetes mellitus in hypopituitary patients is unknown. Objective: The incidence of nonfatal stroke and cardiac events, and prevalence of type 2 diabetes mellitus ( T2D) and cardioprotective medication were compared between cohorts of GH-deficient (GHD) patients and population controls. Design and Participants: The incidence of nonfatal stroke and cardiac events was estimated retrospectively from questionnaires in 750 GHD patients and 2314 matched population controls. A prevalence of T2D and cardioprotective medication was recorded at the distribution of questionnaires. Time since first pituitary deficiency to start of GH therapy was 4 and 2 yr, and time on GH therapy was 6 yr for GHD women and men, respectively. Results: Lifelong incidence of nonfatal stroke was tripled in GHD women and doubled in GHD men, but a decline was seen in both genders during periods after first pituitary hormone deficiency and GHD, during which most patients had GH therapy. The lifelong incidence of nonfatal cardiac events declined in GHD men during first pituitary hormone deficiency and GHD periods. GHD women had a higher prevalence of T2D and lipid-lowering medication, whereas GHD men had a higher prevalence of antihypertensive medication. Conclusions: The declined risks of nonfatal stroke in both genders and of nonfatal cardiac events in GHD men during periods on GH replacement may be caused by prescription of cardioprotective drugs and 6-yr GH replacement. GHD women had an increased prevalence of T2D, partly attributed to higher body mass index and lower physical activity.
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- Wang, Haizhou, et al.
(författare)
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Peduncular attached secondary tiering acrotretoid brachiopods from the Chengjiang fauna : Implications for the ecological expansion of brachiopods during the Cambrian explosion
- 2012
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 323-325, s. 60-67
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Tidskriftsartikel (refereegranskat)abstract
- Brachiopods are usually thought to contribute little to the tiering complexity from the Paleozoic to the Recent, mainly due to the fact that their recent representatives live primarily in lower tiers directly above or below the water-sediment interface. Here we present the first and oldest record of varied levels of secondary tiering in minute brachiopods attached by exceptionally preserved thread-like pedicles around the branched fronds of the algae-like Malongitubus kuangshanensis Hu, 2005. The specimens illustrated herein were recovered from the Chengjiang fauna (Series 2, Stage 3) in the Lower Cambrian Heilinpu Formation at the Kuangshan section in Malong County, Yunnan Province, southern China. The micro-morphology and oval outline of the attached brachiopods demonstrate that they can be assigned to acrotretoid brachiopods (Linguliformea, Lingulata, Acrotretoidea), described here as Kuangshanotreta malungensis gen. et sp. nov. This is the first report on the occurrence of acrotretoid brachiopods in the Lower Cambrian muddy deposits from southern China. The posterior margins of the Kuangshanotreta shells are invariably either in direct contact with, or directed towards, and then in situ attached to the algal frond of M. kuangshanensis, indicating a secondary tiering in the ecological structure of Early Cambrian brachiopods. The acrotretoid Kuangshanotreta/algae malongitubus association represents both the first and oldest evidence into the enigmatic paleoecology of the diverse acrotretoid linguliformean stock that comprises an important component of the Cambrian evolutionary fauna, and sheds light on medium-high levels of secondary tiering (+5 to +10 cm) Cambrian soft substrate suspension-feeding communities. When compared to other Chengjiang brachiopods, the miniature morphology and concomitant weight reduction of the shell of K. malungensis may be a good adaption to a suspended epifaunal tiering life style. We infer that the diversification of micromorphic and miniaturized acrotretoids that occurred from the Middle Cambrian to Early Ordovician may be the result of the increased availability of habitable surfaces provided by high levels of tiering in new types of ecological spaces.
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