scholarly journals Comparative osteohistology of Hesperornis with reference to pygoscelid penguins: the effects of climate and behaviour on avian bone microstructure

2014 ◽  
Vol 1 (3) ◽  
pp. 140245 ◽  
Author(s):  
Laura E. Wilson ◽  
Karen Chin
Keyword(s):  
Late Cretaceous ◽  
Bone Growth ◽  
Skeletal Maturity ◽  
Large Body ◽  
Bone Microstructure ◽  
The Arctic ◽  
Polar Climate ◽  
Show Evidence ◽  
Bone Deposition ◽  
Pygoscelid Penguins

The broad biogeographic distribution of Hesperornis fossils in Late Cretaceous Western Interior Seaway deposits has prompted questions about whether they endured polar winters or migrated between mid- and high latitudes. Here, we compare microstructures of hesperornithiform long bones from Kansas and the Arctic to investigate whether migration or Late Cretaceous polar climate affected bone growth. We also examine modern penguin bones to determine how migration and climate may influence bone growth in birds with known behaviours. Histological analysis of hesperornithiform samples reveals continuous bone deposition throughout the cortex, plus an outer circumferential layer in adults. No cyclic growth marks, zonation or differences in vasculature are apparent in the Hesperornis specimens. Comparatively, migratory Adélie and chinstrap penguin bones show no zonation or changes in microstructure, suggesting that migration is not necessarily recorded in avian bone microstructure. Non-migratory gentoos show evidence of rapid bone growth possibly associated with increased chick growth rates in high-latitude populations and large body size. The absence of histological evidence for migration in extinct Hesperornis and extant pygoscelid penguins may reflect that these birds reached skeletal maturity before migration or overwintering. This underscores the challenges of using bone microstructure to infer the effects of behaviour and climate on avian growth.

18F-sodium fluoride bone deposition quantitation with PET in Mice: Variation with age, sex, and circadian rhythm

2020 ◽  
Vol 59 (06) ◽  
pp. 428-437
Author(s):  
Viktoria Dorau-Rutke ◽  
Kai Huang ◽  
Mathias Lukas ◽  
Marc O. Schulze ◽  
Christian Rosner ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Sodium Fluoride ◽  
Bone Growth ◽  
Bone Volume ◽  
Sleep Phase ◽  
Median Percentage ◽  
Bone Uptake ◽  
Pooled Data ◽  
Uptake Studies ◽  
Bone Deposition

Abstract Aim The aim of this study was to establish a data base for normal 18F-sodium fluoride (18F-NaF) bone uptake as a function of age, sex and circadian rhythm in mice. Methods In 12 female (F) and 12 male (M) C57BL/6N mice PET images were acquired 90 min after intravenous injection of 20 MBq 18F-NaF for 30 minutes. Each mouse was imaged in follow-up studies at 1, 3, 6, 13 and 21 months of age. In order to assess for physiologic changes related to circadian rhythm, animals were imaged during light (sleep phase) as well as during night conditions (awake phase). Bone uptake is described as the median percentage of the injected activity (%IA) and in relation to bone volume (%IA/ml). Results A significant smaller bone volume was found in F (1.79 ml) compared to M (1.99 ml; p < 0.001). In sex-pooled data, highest bone uptake occurred at an age of 1 month (61.1 %IA, 44.5 %IA/ml) with a significant reduction (p < 0.001) at age 3 months (43.6 %IA, 23.6 %IA/ml), followed by an increase between 13 (47.3 %IA, 24.5 %IA/ml) and 21 months (52.2 %IA, 28.1 %IA/ml). F had a significantly higher total uptake (F 48.2 %IA, M 43.8 %IA; p = 0.026) as well as a higher uptake per ml bone tissue (F 27.0 %IA/ml; M 22.4 %IA/ml; p < 0.001). A significant impact of circadian rhythm was only found for F at ages of 3 and 6 months with a higher uptake during the sleep phase. Conclusion Circadian rhythm had a significant impact on uptake only in F of 3 and 6 months. Regarding sex, F showed generally higher uptake rates than M. The highest uptake values were observed during bone growth at age 1 month in both sexes, a second uptake peak occurred in elderly F. Designing future bone uptake studies with M, attention must be paid to age only, while in F circadian rhythm and age must be taken into account.

scholarly journals Environmental Sustainability and Economic Growth in Greenland: Testing the Environmental Kuznets Curve

2021 ◽  
Vol 13 (3) ◽  
pp. 1228
Author(s):  
Javier Arnaut ◽  
Johanna Lidman
Keyword(s):  
Environmental Sustainability ◽  
Environmental Kuznets Curve ◽  
Development Stage ◽  
The Arctic ◽  
Kuznets Curve ◽  
Distributed Lag ◽  
Show Evidence ◽  
Per Capita ◽  
Growing Economy ◽  
High Level

The environmental Kuznets curve (EKC) hypothesis assumes there is an inverted U-shape relationship between pollution and income per capita, implying an improvement in environmental quality when a growing economy reaches a high level of economic development. This study evaluated empirically the existence of the environmental Kuznets curve in Greenland for the period 1970–2018. Using an autoregressive distributed lag (ARDL) approach, the results show evidence of a U-shaped EKC in Greenland instead of the hypothesized inverted U-shape. The findings indicate that Greenland had initially experienced a decoupling transition during an early development stage associated with structural conditions of a small subsistence economy. However, once the country began to expand its industry, the trend began to reverse, creating a positive and significant relationship between CO2 emissions and GDP per capita that is potentially detrimental to the Arctic natural environment.

scholarly journals Geological evolution of the Chalk Group in the northern Dutch North Sea: inversion, sedimentation and redeposition

2018 ◽  
Vol 156 (07) ◽  
pp. 1265-1284
Author(s):  
EVA VAN DER VOET ◽  
LEONORA HEIJNEN ◽  
JOHN J. G. REIJMER
Keyword(s):  
North Sea ◽  
Late Cretaceous ◽  
Seismic Survey ◽  
Structural Elements ◽  
The North ◽  
Show Evidence ◽  
New Finding ◽  
The North Sea ◽  
Thickness Variations ◽  
Well Data

AbstractIn contrast to the Norwegian and Danish sectors, where significant hydrocarbon reserves were found in chalk reservoirs, limited studies exist analysing the chalk evolution in the Dutch part of the North Sea. To provide a better understanding of this evolution, a tectono-sedimentary study of the Late Cretaceous to Early Palaeogene Chalk Group in the northern Dutch North Sea was performed, facilitated by a relatively new 3D seismic survey. Integrating seismic and biostratigraphic well data, seven chronostratigraphic units were mapped, allowing a reconstruction of intra-chalk geological events.The southwestward thickening of the Turonian sequence is interpreted to result from tilting, and the absence of Coniacian and Santonian sediments in the western part of the study area is probably the result of non-deposition. Seismic truncations show evidence of a widespread inversion phase, the timing of which differs between the structural elements. It started at the end of the Campanian followed by a second pulse during the Maastrichtian, a new finding not reported before. After subsidence during the Maastrichtian and Danian, renewed inversion and erosion occurred at the end of the Danian. Halokinesis processes resulted in thickness variations of chalk units of different ages.In summary, variations in sedimentation patterns in the northern Dutch North Sea relate to the Sub-Hercynian inversion phase during the Campanian and Maastrichtian, the Laramide inversion phase at the end of the Danian, and halokinesis processes. Additionally, the Late Cretaceous sea floor was characterized by erosion through contour bottom currents at different scales and resedimentation by slope failures.

Nanotechnology Enabled In Situ Orthopaedic Sensors for Personalized Medicine

2012 ◽  
Vol 86 ◽  
pp. 40-50
Author(s):  
Sirinrath Sirivisoot ◽  
Thomas J. Webster
Keyword(s):  
Bone Growth ◽  
Electrochemical Sensors ◽  
Electrochemical Analysis ◽  
Matrix Proteins ◽  
Implant Design ◽  
Implant Surface ◽  
Cellular Events ◽  
Bone Deposition ◽  
Made In

Although improvements have been made in implant design to increase bone formation and promote successful osseointegration using nanotechnology, the clinical diagnosis of early bone growth surrounding implants remains problematic. The development of a device allowing doctors to monitor the healing cascade and to diagnose potential infection or inflammation is necessary. Biological detection can be examined by the electrochemical analysis of electron transfer (or redox) reactions of extracellular matrix proteins involved in bone deposition and resorption. The use of nanomaterials as signal amplifiers in electrochemical sensors has greatly improved the sensitivity of detection. Nanotechnology-enabled electrochemical sensors that can be placed on the implant surface itself show promise as self-diagnosing devices in situ, possibly to detect new bone growth surrounding the implant and other cellular events to ensure implant success.

scholarly journals Accelerated evolution and diversifying selection drove the adaptation of cetacean bone microstructure

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Di Sun ◽  
Xuming Zhou ◽  
Zhenpeng Yu ◽  
Shixia Xu ◽  
Inge Seim ◽  
...  
Keyword(s):  
Bone Development ◽  
Bone Microstructure ◽  
Divergent Evolution ◽  
Behavioral Adaptations ◽  
Accelerated Evolution ◽  
Genes Encoding ◽  
Show Evidence ◽  
Evolutionary Event ◽  
Osteoclast Function ◽  
Specialized Structure

Abstract Background The transition from land to sea by the ancestor of cetaceans approximately 50 million years ago was an incredible evolutionary event that led to a series of morphological, physiological, and behavioral adaptations. During this transition, bone microstructure evolved from the typical terrestrial form to the specialized structure found in modern cetaceans. While the bone microstructure of mammals has been documented before, investigations of its genetic basis lag behind. The increasing number of cetaceans with whole-genome sequences available may shed light on the mechanism underlying bone microstructure evolution as a result of land to water transitions. Results Cetacean bone microstructure is consistent with their diverse ecological behaviors. Molecular evolution was assessed by correlating bone microstructure and gene substitution rates in terrestrial and aquatic species, and by detecting genes under positive selection along ancestral branches of cetaceans. We found that: 1) Genes involved in osteoclast function are under accelerated evolution in cetaceans, suggestive of important roles in bone remodeling during the adaptation to an aquatic environment; 2) Genes in the Wnt pathway critical for bone development and homeostasis show evidence of divergent evolution in cetaceans; 3) Several genes encoding bone collagens are under selective pressure in cetaceans. Conclusions Our results suggest that evolutionary pressures have shaped the bone microstructure of cetaceans, to facilitate life in diverse aquatic environments.

scholarly journals Cretaceous vegetational change: a biomal perspective

1992 ◽  
Vol 6 ◽  
pp. 295-295
Author(s):  
Garland R. Upchurch
Keyword(s):  
Species Diversity ◽  
North America ◽  
Late Cretaceous ◽  
High Latitude ◽  
Deciduous Forest ◽  
Terrestrial Ecosystems ◽  
High Latitudes ◽  
Coastal Regions ◽  
Show Evidence ◽  
Angiosperm Pollen

The Cretaceous rise of flowering plants marked an important transition in the modernization of terrestrial ecosystems. Well documented is the diversification of angiosperm pollen during the mid-Cretaceous and the migration of angiosperms from low latitudes to middle and high latitudes during the Barremian to Cenomanian. Global compilations of “species” diversity indicate a rapid rise in angiosperm diversity during the Albian to Cenomanian. This rise parallels a decline in the species diversity of archaic pteridophytes and the gymnosperm orders Cycadales, Bennettitales, Ginkgoales, Czekanowskiales, and Caytoniales. Late Cretaceous floras show more gradual trends in species diversity than mid-Cretaceous floras.Megafloral reconstructions of vegetation and climate for North America and other continents indicate warm temperatures in coastal regions of middle to high latitudes. Cretaceous biomes, however, often cannot be compared closely with Recent biomes. During much of the Cretaceous, conifers and other gymnosperms shared dominance with angiosperms in tropical and subtropical vegetation, unlike the Recent. During the Late Cretaceous, tropical rainforest was areally restricted. The few known leaf megafloras from equatorial regions indicate subhumid, rather than rainforest, conditions. Desert and semi-desert were widespread at lower latitudes and are documented by the occurrence of evaporite minerals in China, Africa, Spain, Mexico, and South America. Mid-latitude vegetation consisted of open-canopy broadleaved and coniferous evergreen woodlands that existed under subhumid conditions and low seasonality. High-latitude vegetation of the Northern Hemisphere consisted of coniferous and broadleaved deciduous forest, rather than boreal forest and tundra. High-latitude vegetation from coastal regions of the Southern Hemisphere consisted of evergreen conifers and angiosperms. Rainforest conditions appear to have been largely restricted to polar latitudes.Data on relative abundance, though often incomplete, indicate that angiosperms became ecologically important in tropical to warm subtropical broadleaved evergreen forests and woodlands by the Cenomanian. However, their rise to dominance took longer in other biomes. Conifers formed an important component of many Late Cretaceous biomes, and the persistence of archaic gymnosperms was strongly influenced by climate. Deciduous Ginkgoales, Czekanowskiales, Bennettitales, and Caytoniales are rare to absent in Late Cretaceous megafloras from warm subtropical to tropical climates, but they persist in megafloras from cooler climates. Archaic conifers such as Frenelopsis occur in megafloras representing low-latitude desert and semi-desert, but they are generally absent in more humid assemblages. Within mid-latitude broadleaved and coniferous evergreen woodland from North America, conifers show evidence for co-dominance with angiosperms into the early Maastrichtian. However, this co-dominance appears to have ended by latest Maastrichtian, which implies that vegetational reorganization occurred during the last few million years of the Cretaceous in North America.

CRETACEOUS VERTEBRATES FROM THE ANDERSON RIVER N.W.T.

1967 ◽  
Vol 4 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Dale A. Russell
Keyword(s):  
Arctic Ocean ◽  
Late Cretaceous ◽  
The Arctic ◽  
Lower Horizon ◽  
The Arctic Ocean

Vertebrate remains have been recovered from two horizons in late Cretaceous strata along the east bank of the Anderson River at latitude 69 °N. The lower horizon has produced a fauna very similar to that of the Niobrara Chalk in western Kansas, including mosasaurs, plesiosaurs, and abundant toothed birds. The upper horizon has yielded a moderately short-necked plesiosaur of cimoliasaurian affinities. These vertebrates lived in or near a strait linking the Arctic Ocean with the interior sea in very late Cretaceous time.

scholarly journals Effect of sex steroids on plasma C-type natriuretic peptide forms: stimulation by oestradiol in lambs and adult sheep

2008 ◽  
Vol 199 (3) ◽  
pp. 481-487 ◽  
Author(s):  
Timothy C R Prickett ◽  
Graham K Barrell ◽  
Martin Wellby ◽  
Timothy G Yandle ◽  
A Mark Richards ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Bone Growth ◽  
Skeletal Maturity ◽  
Live Weight ◽  
Surgical Removal ◽  
Adult Sheep ◽  
Amino Terminal ◽  
Reproductive Tissues ◽  
Ewe Lambs ◽  
Exogenous Oestrogen

Although C-type natriuretic peptide (CNP) is crucial to post-natal endochondral growth, roles for the hormone in pubertal bone growth and the physiological effects of sex steroid substitution on CNP synthesis are not known. Using a plasma marker of CNP tissue synthesis (amino-terminal proCNP, NTproCNP), we have studied the effect of exogenous oestrogen (E2) or testosterone (T) on plasma CNP forms and bone alkaline phosphatase (bALP) in pre-pubertal lambs. Responses to E2 in non-cycling adult ewes were also studied. In 15-week-old intact ewe lambs, E2 promptly increased plasma NTproCNP and CNP (P<0.001) to peak on day 2, and bALP (P<0.001 peaking on day 7), whereas no significant stimulation in response to T was observed in male lambs. Linear bone growth and live weight were unaffected. In adult anoestrous ewes, basal concentrations of CNP forms and bALP were lower than in ewe lambs, in keeping with skeletal maturity, but adults responded similarly to E2. Prompt and sustained increases in NTproCNP and CNP, and a later threefold rise in bALP (all P<0.001), were induced by E2. Possible contributions to these increases in plasma CNP forms by reproductive tissues (a known site of E2-induced CNP expression) were excluded by showing similar E2-induced CNP responses in adult ewes after surgical removal of reproductive tissues. These results are the first to show that E2 stimulates plasma CNP forms and bALP in lambs and adult sheep and raise the possibility that CNP also participates in bone formation in the mature skeleton.

scholarly journals Histological variability in the limb bones of the Asiatic wild ass and its significance for life history inferences

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2580 ◽  
Author(s):  
Carmen Nacarino-Meneses ◽  
Xavier Jordana ◽  
Meike Köhler
Keyword(s):  
Life History ◽  
Bone Tissue ◽  
Bone Growth ◽  
Skeletal Maturity ◽  
Life History Strategy ◽  
Conservation Strategies ◽  
Limb Bones ◽  
Equus Hemionus ◽  
Wild Ass ◽  
Asiatic Wild Ass

The study of bone growth marks (BGMs) and other histological traits of bone tissue provides insights into the life history of present and past organisms. Important life history traits like longevity or age at maturity, which could be inferred from the analysis of these features, form the basis for estimations of demographic parameters that are essential in ecological and evolutionary studies of vertebrates. Here, we study the intraskeletal histological variability in an ontogenetic series of Asiatic wild ass (Equus hemionus) in order to assess the suitability of several skeletal elements to reconstruct the life history strategy of the species. Bone tissue types, vascular canal orientation and BGMs have been analyzed in 35 cross-sections of femur, tibia and metapodial bones of 9 individuals of different sexes, ages and habitats. Our results show that the number of BGMs recorded by the different limb bones varies within the same specimen. Our study supports that the femur is the most reliable bone for skeletochronology, as already suggested. Our findings also challenge traditional beliefs with regard to the meaning of deposition of the external fundamental system (EFS). In the Asiatic wild ass, this bone tissue is deposited some time after skeletal maturity and, in the case of the femora, coinciding with the reproductive maturity of the species. The results obtained from this research are not only relevant for future studies in fossilEquus, but could also contribute to improve the conservation strategies of threatened equid species.

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